From f9679d8ae7199b2aba04614d7927a3dcd57c2bf3 Mon Sep 17 00:00:00 2001 From: Paolo Carlini Date: Fri, 11 Dec 2009 17:23:09 +0000 Subject: [PATCH] lwg-active.html: Update to Revision R68. 2009-12-11 Paolo Carlini * doc/html/ext/lwg-active.html: Update to Revision R68. * doc/html/ext/lwg-closed.html: Likewise. * doc/html/ext/lwg-defects.html: Likewise. * doc/xml/manual/intro.xml: Update status of issues 431, 630, and 696. From-SVN: r155170 --- libstdc++-v3/ChangeLog | 7 + libstdc++-v3/doc/html/ext/lwg-active.html | 24359 ++++++++----------- libstdc++-v3/doc/html/ext/lwg-closed.html | 13278 +++++++++- libstdc++-v3/doc/html/ext/lwg-defects.html | 5227 +++- libstdc++-v3/doc/xml/manual/intro.xml | 6 +- 5 files changed, 27878 insertions(+), 14999 deletions(-) diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog index cab2d6bb875..31224f32367 100644 --- a/libstdc++-v3/ChangeLog +++ b/libstdc++-v3/ChangeLog @@ -1,3 +1,10 @@ +2009-12-11 Paolo Carlini + + * doc/html/ext/lwg-active.html: Update to Revision R68. + * doc/html/ext/lwg-closed.html: Likewise. + * doc/html/ext/lwg-defects.html: Likewise. + * doc/xml/manual/intro.xml: Update status of issues 431, 630, and 696. + 2009-12-10 Jakub Jelinek PR c++/42317 diff --git a/libstdc++-v3/doc/html/ext/lwg-active.html b/libstdc++-v3/doc/html/ext/lwg-active.html index 74e43ef277c..15281f31ff8 100644 --- a/libstdc++-v3/doc/html/ext/lwg-active.html +++ b/libstdc++-v3/doc/html/ext/lwg-active.html @@ -7,6 +7,14 @@ @@ -14,11 +22,11 @@ del {background-color:#FFA0A0} - + - + @@ -29,7 +37,7 @@ del {background-color:#FFA0A0}
Doc. no.N2940=09-0130N3011=09-0201
Date:2009-08-022009-11-08
Project:Howard Hinnant <howard.hinnant@gmail.com>
-

C++ Standard Library Active Issues List (Revision R66)

+

C++ Standard Library Active Issues List (Revision R68)

Reference ISO/IEC IS 14882:2003(E)

Also see:

@@ -82,9 +90,139 @@ del {background-color:#FFA0A0} can be found in the comp.std.c++ FAQ.

+

How to submit an issue

+ +
    +
  1. +Mail your issue to the author of this list. +
    2. +
  2. +Specify a short descriptive title. If you fail to do so, the subject line of your +mail will be used as the issue title. +
    3. +
  3. +If the "From" on your email is not the name you wish to appear as issue submitter, +then specify issue submitter. +
    4. +
  4. +Provide a brief discussion of the problem you wish to correct. Refer to the latest +working draft or standard using [section.tag] and paragraph numbers where appropriate. +
    5. +
  5. +Provide proposed wording. This should indicate exactly how you want the standard +to be changed. General solution statements belong in the discussion area. This +area contains very clear and specific directions on how to modify the current +draft. If you are not sure how to word a solution, you may omit this part. +But your chances of a successful issue greatly increase if you attempt wording. +
    6. +
  6. +It is not necessary for you to use html markup. However, if you want to, you can +<ins>insert text like this</ins> and <del>delete text like +this</del>. The only strict requirement is to communicate clearly to +the list maintainer exactly how you want your issue to look. +
    7. +
  7. +It is not necessary for you to specify other html font/formatting +mark-up, but if you do the list maintainer will attempt to respect your +formatting wishes (as described by html markup, or other common idioms). +
    8. +
  8. +It is not necessary for you to specify open date or last modified date (the date +of your mail will be used). +
    9. +
  9. +It is not necessary for you to cross reference other issues, but you can if you +like. You do not need to form the hyperlinks when you do, the list maintainer will +take care of that. +
    10. +
  10. +One issue per email is best. +
    11. +
  11. +Between the time you submit the issue, and the next mailing deadline +(date at the top of the Revision History), you own this issue. +You control the content, the stuff that is right, the stuff that is +wrong, the format, the misspellings, etc. You can even make the issue +disappear if you want. Just let the list maintainer know how you want +it to look, and he will try his best to accommodate you. After the +issue appears in an official mailing, you no longer enjoy exclusive +ownership of it. +
    12. +
+

Revision History

@@ -146,24 +284,24 @@ del {background-color:#FFA0A0}
  • 1143 issues total, up by 32.
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    • @@ -176,7 +314,7 @@ del {background-color:#FFA0A0}
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    • @@ -253,28 +391,28 @@ del {background-color:#FFA0A0}
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  • Details:
  • Details:
    • Added the following New issues: 755, 756, 757, 758, 759, 760, 761, 762, 763, 764.
      • -
    • Changed the following issues from NAD to Open: 463.
      • +
    • Changed the following issues from NAD to Open: 463.
    • Changed the following issues from Pending WP to WP: 607, 608, 654, 655, 677, 682.
    • @@ -436,7 +574,7 @@ del {background-color:#FFA0A0}
  • Changed the following issues from NAD Future to Dup: 77, 350.
  • Changed the following issues from New to NAD: 639, 657, 663.
  • Changed the following issues from Open to NAD: 548.
    • -
  • Changed the following issues from New to Open: 546, 550, 564, 565, 573, 585, 588, 627, 629, 630, 632, 635, 653, 659, 667, 668, 669, 670, 671, 673, 686, 704, 707, 708.
    • +
  • Changed the following issues from New to Open: 546, 550, 564, 565, 573, 585, 588, 627, 629, 630, 632, 635, 653, 659, 667, 668, 669, 670, 671, 673, 686, 704, 707, 708.
  • Changed the following issues from New to Pending NAD Editorial: 393, 592.
  • Changed the following issues from New to Pending WP: 607, 608, 654, 655, 677, 682.
  • Changed the following issues from New to Ready: 561, 562, 563, 567, 581, 595, 620, 621, 622, 623, 624, 661, 664, 665, 666, 674, 675, 676, 679, 687, 688, 689, 693, 694, 695, 700, 703, 705, 706.
    • @@ -457,7 +595,7 @@ del {background-color:#FFA0A0}
  • 723 issues total, up by 15.
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  • 696 issues total, up by 20.
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  • 619 issues total, up by 10.
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  • 592 issues total, up by 5.
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  • 535 issues total.
  • Details:
    • @@ -661,7 +799,7 @@ del {background-color:#FFA0A0} Added new issues 526-528. Moved issues 280, 461, 464, 465, 467, 468, 474, 496 from Ready to WP as per the vote from Mont Tremblant. Moved issues 247, 294, 342, 362, 369, 371, 376, 384, 475, 478, 495, 497 from Review to Ready. -Moved issues 498, 504, 506, 509, 510, 511, 512, 513, 514 from New to Open. +Moved issues 498, 504, 506, 509, 510, 511, 512, 513, 514 from New to Open. Moved issues 505, 507, 508, 519 from New to Ready. Moved issue 500 from New to NAD. Moved issue 518 from New to Review. @@ -673,7 +811,7 @@ Added new issues 498-503. +Added new issues 498-503.
  • R36: 2005-04 post-Lillehammer mailing. All issues in "ready" status except @@ -697,7 +835,7 @@ new issues 463-478. +new issues 463-478.
  • R30: Post-Sydney mailing: reflects decisions made at the Sydney meeting. @@ -712,7 +850,7 @@ Post-Kona mailing: reflects decisions made at the Kona meeting. Added new issues 432-440.
  • R27: -Pre-Kona mailing. Added new issues 404-431. +Pre-Kona mailing. Added new issues 404-431.
  • R26: Post-Oxford mailing: reflects decisions made at the Oxford meeting. @@ -1007,614 +1145,184 @@ format, 96. Vector<bool> is not a container -

    Section: 23.3.6 [vector] Status: Open - Submitter: AFNOR Opened: 1998-10-07 Last modified: 2009-07-29

    -

    View other active issues in [vector].

    -

    View all other issues in [vector].

    -

    View all issues with Open status.

    -

    Discussion:

    -

    vector<bool> is not a container as its reference and -pointer types are not references and pointers.

    - -

    Also it forces everyone to have a space optimization instead of a -speed one.

    - -

    See also: 99-0008 == N1185 Vector<bool> is -Nonconforming, Forces Optimization Choice.

    - -

    [In Santa Cruz the LWG felt that this was Not A Defect.]

    - - -

    [In Dublin many present felt that failure to meet Container -requirements was a defect. There was disagreement as to whether -or not the optimization requirements constituted a defect.]

    - - -

    [The LWG looked at the following resolutions in some detail: -
    -     * Not A Defect.
    -     * Add a note explaining that vector<bool> does not meet -Container requirements.
    -     * Remove vector<bool>.
    -     * Add a new category of container requirements which -vector<bool> would meet.
    -     * Rename vector<bool>.
    -
    -No alternative had strong, wide-spread, support and every alternative -had at least one "over my dead body" response.
    -
    -There was also mention of a transition scheme something like (1) add -vector_bool and deprecate vector<bool> in the next standard. (2) -Remove vector<bool> in the following standard.]

    - - -

    [Modifying container requirements to permit returning proxies -(thus allowing container requirements conforming vector<bool>) -was also discussed.]

    - - -

    [It was also noted that there is a partial but ugly workaround in -that vector<bool> may be further specialized with a customer -allocator.]

    - - -

    [Kona: Herb Sutter presented his paper J16/99-0035==WG21/N1211, -vector<bool>: More Problems, Better Solutions. Much discussion -of a two step approach: a) deprecate, b) provide replacement under a -new name. LWG straw vote on that: 1-favor, 11-could live with, 2-over -my dead body. This resolution was mentioned in the LWG report to the -full committee, where several additional committee members indicated -over-my-dead-body positions.]

    - - -

    Discussed at Lillehammer. General agreement that we should - deprecate vector<bool> and introduce this functionality under - a different name, e.g. bit_vector. This might make it possible to - remove the vector<bool> specialization in the standard that comes - after C++0x. There was also a suggestion that - in C++0x we could additional say that it's implementation defined - whether vector<bool> refers to the specialization or to the - primary template, but there wasn't general agreement that this was a - good idea.

    - -

    We need a paper for the new bit_vector class.

    - -

    [ -Batavia: -]

    - -
    -The LWG feels we need something closer to SGI's bitvector to ease migration -from vector<bool>. Although some of the funcitonality from -N2050 -could well be used in such a template. The concern is easing the API migration for those -users who want to continue using a bit-packed container. Alan and Beman to work. -
    - -

    [ -Post Summit Alisdair adds: -]

    - - -
    -

    -vector<bool> is now a conforming container under the revised terms of C++0x, -which supports containers of proxies. -

    -

    -Recommend NAD. -

    -

    -Two issues remain: -

    -

    -i/ premature optimization in the specification. -There is still some sentiment that deprecation is the correct way to go, -although it is still not clear what it would mean to deprecate a single -specialization of a template. -

    -

    -Recommend: Create a new issue for the discussion, leave as Open. -

    -

    -ii/ Request for a new bitvector class to guarantee the optimization, perhaps -with a better tuned interface. -

    -

    -This is a clear extension request that may be handled via a future TR. -

    -
    - -

    [ -Batavia (2009-05): -]

    - -
    -We note that most of this issue has become moot over time, -and agree with Alisdair's recommendations. -Move to NAD Future for reconsideration of part (ii). -
    - -

    [ -2009-07-29 Alisdair reopens: -]

    - - -
    -

    -This infamous issue was closed as NAD Future when concepts introduced -support for proxy iterators, so the only remaining requirement was to -provide a better type to support bitsets of dynamic length. I fear we -must re-open this issue until the post-concept form of iterators is -available, and hopefully will support the necessary proxy functionality -to allow us to close this issue as NAD. -

    - -

    -I recommend we spawn a separate issue (1184) requesting a dynamic length bitset -and pre-emptively file it as NAD Future. It is difficult to resolve #96 -when it effectively contains two separate sub-issues. -

    -
    - - -

    Proposed resolution:

    -

    -We now have: -N2050 -and -N2160. -

    - - - - - - -
    -

    149. Insert should return iterator to first element inserted

    -

    Section: 23.2.3 [sequence.reqmts] Status: Ready - Submitter: Andrew Koenig Opened: 1999-06-28 Last modified: 2009-07-15

    -

    View all other issues in [sequence.reqmts].

    +

    296. Missing descriptions and requirements of pair operators

    +

    Section: 20.3.4 [pairs] Status: Ready + Submitter: Martin Sebor Opened: 2001-01-14 Last modified: 2009-10-26

    +

    View other active issues in [pairs].

    +

    View all other issues in [pairs].

    View all issues with Ready status.

    Discussion:

    -

    Suppose that c and c1 are sequential containers and i is an -iterator that refers to an element of c. Then I can insert a copy of -c1's elements into c ahead of element i by executing

    - -
    - -
    c.insert(i, c1.begin(), c1.end());
    - -
    - -

    If c is a vector, it is fairly easy for me to find out where the -newly inserted elements are, even though i is now invalid:

    - -
    - -
    size_t i_loc = i - c.begin();
-c.insert(i, c1.begin(), c1.end());
    - -
    - -

    and now the first inserted element is at c.begin()+i_loc and one -past the last is at c.begin()+i_loc+c1.size().
    -
    -But what if c is a list? I can still find the location of one past the -last inserted element, because i is still valid. To find the location -of the first inserted element, though, I must execute something like

    - -
    - -
    for (size_t n = c1.size(); n; --n)
-   --i;
    - -
    - -

    because i is now no longer a random-access iterator.
    -
    -Alternatively, I might write something like

    - -
    - -
    bool first = i == c.begin();
-list<T>::iterator j = i;
-if (!first) --j;
-c.insert(i, c1.begin(), c1.end());
-if (first)
-   j = c.begin();
-else
-   ++j;
    - -
    - -

    which, although wretched, requires less overhead.
    -
    -But I think the right solution is to change the definition of insert -so that instead of returning void, it returns an iterator that refers -to the first element inserted, if any, and otherwise is a copy of its -first argument. 

    +

    The synopsis of the header <utility> in 20.3 [utility] +lists the complete set of equality and relational operators for pair +but the section describing the template and the operators only describes +operator==() and operator<(), and it fails to mention +any requirements on the template arguments. The remaining operators are +not mentioned at all. +

    [ -Summit: -]

    - - -
    -Reopened by Alisdair. -
    - -

    [ -Post Summit Alisdair adds: +2009-09-27 Alisdair reopens. ]

    -In addition to the original rationale for C++03, this change also gives a -consistent interface for all container insert operations i.e. they all -return an iterator to the (first) inserted item. +The issue is a lack of wording specifying the semantics of std::pair +relational operators. The rationale is that this is covered by +catch-all wording in the relops component, and that as relops directly +precedes pair in the document this is an easy connection to make.

    -Proposed wording provided. +Reading the current working paper I make two observations:

    + +
      +
    1. +relops no longer immediately precedes pair in the order of +specification. However, even if it did, there is a lot of pair +specification itself between the (apparently) unrelated relops and the +relational operators for pair. (The catch-all still requires +operator== and operator< to be specified +explicitly) +
      2. + +
    2. +No other library component relies on the catch-all clause. The following +all explicitly document all six relational operators, usually in a +manner that could have deferred to the relops clause. +
      3. +
    + +
    tuple
+unique_ptr
+duration
+time_point
+basic_string
+queue
+stack
+move_iterator
+reverse_iterator 
+regex submatch
+thread::id
+
    + +

    +The container components provide their own (equivalent) definition in +23.2.1 [container.requirements.general] Table 90 -- Container +requirements and do so do not defer to relops. +

    + +

    +Shared_ptr explicitly documents operator!= and does +not supply the other 3 missing operators +(>,>=,<=) so does not meet the +reqirements of the relops clause. +

    + +

    +Weak_ptr only supports operator< so would not be +covered by relops. +

    + +

    +At the very least I would request a note pointing to the relops clause +we rely on to provide this definition. If this route is taken, I would +recommend reducing many of the above listed clauses to a similar note +rather than providing redundant specification. +

    + +

    +My preference would be to supply the 4 missing specifications consistent +with the rest of the library. +

    +

    [ -2009-07 Frankfurt +2009-10-11 Daniel opens 1233 which deals with the same issue as +it pertains to unique_ptr. +]

    + + +

    [ +2009-10 Santa Cruz: ]

    -

    -Q: why isn't this change also proposed for associative containers? -

    - -

    -A: The returned iterator wouldn't necessarily point to a contiguous range. -

    - -

    -Moved to Ready. -

    +Move to Ready

    Proposed resolution:

    - Table 83 -change return type from void to iterator for the following rows: -

    +After p20 20.3.4 [pairs] add: +

    + +
    template <class T1, class T2>
+bool operator!=(const pair<T1,T2>& x, const pair<T1,T2>& y);
+
    - - - - - - - - - - - - - - - - - - - - - - - - -
    Table 83 -- Sequence container requirements (in addition to container)
    ExpressionReturn typeAssertion/note pre-/post-condition
    -a.insert(p,n,t) - -void iterator - -Inserts n copies of t before p. -
    -a.insert(p,i,j) - -void iterator - -Each iterator in the range [i,j) shall be -dereferenced exactly once. -pre: i and j are not iterators into a. -Inserts copies of elements in [i, j) before p -
    -a.insert(p,il) - -void iterator - -a.insert(p, il.begin(), il.end()). -
    +Returns: !(x==y)
    -

    -Add after p6 23.2.3 [sequence.reqmts]: -

    +
    template <class T1, class T2>
+bool operator> (const pair<T1,T2>& x, const pair<T1,T2>& y);
+
    -

    -6- ...

    - -

    -The iterator returned from a.insert(p,n,t) points to the copy of the -first element inserted into a, or p if n == 0. -

    - -

    -The iterator returned from a.insert(p,i,j) points to the copy of the -first element inserted into a, or p if i == j. -

    - -

    -The iterator returned from a.insert(p,il) points to the copy of the -first element inserted into a, or p if il is empty. -

    - +Returns: y < x
    -

    -p2 23.3.2 [deque] Update class definition, change return type -from void to iterator: -

    - -
    void iterator insert(const_iterator position, size_type n, const T& x);
-template <class InputIterator>
-  void iterator insert(const_iterator position, InputIterator first, InputIterator last);
-  void iterator insert(const_iterator position, initializer_list<T>);
-
    - -

    -23.3.2.3 [deque.modifiers] change return type from void to iterator on following declarations: -

    - -
      void iterator insert(const_iterator position, size_type n, const T& x);
-template <class InputIterator>
-  void iterator insert(const_iterator position, InputIterator first, InputIterator last);
-
    - -

    -Add the following (missing) declaration -

    - -
    iterator insert(const_iterator position, initializer_list<T>);
-
    - -

    -23.3.3 [forwardlist] Update class definition, change return type -from void to iterator: -

    - -
    void iterator insert_after(const_iterator position, initializer_list<T> il);
-void iterator insert_after(const_iterator position, size_type n, const T& x);
-template <class InputIterator>
-  void iterator insert_after(const_iterator position, InputIterator first, InputIterator last);
-
    - -

    -p8 23.3.3.4 [forwardlist.modifiers] change return type from void to iterator: -

    - -
    void iterator insert_after(const_iterator position, size_type n, const T& x);
-
    - -

    -Add paragraph: -

    +
    template <class T1, class T2>
+bool operator>=(const pair<T1,T2>& x, const pair<T1,T2>& y);
+
    -Returns: position. +Returns: !(x < y)
    -

    -p10 23.3.3.4 [forwardlist.modifiers] change return type from void to iterator: -

    - -
    template <class InputIterator>
-  void iterator insert_after(const_iterator position, InputIterator first, InputIterator last);
-
    - -

    -Add paragraph: -

    +
    template <class T1, class T2>
+bool operator<=(const pair<T1,T2>& x, const pair<T1,T2>& y);
+
    -Returns: position. +Returns: !(y < x)
    - -

    -p12 23.3.3.4 [forwardlist.modifiers] change return type from void to iterator on following declarations: -

    - -
    void iterator insert_after(const_iterator position, initializer_list<T> il);
-
    - -

    -change return type from void to iterator on following declarations: -

    - -

    -p2 23.3.4 [list] Update class definition, change return type from void to iterator: -

    - -
    void iterator insert(const_iterator position, size_type n, const T& x);
-
-template <class InputIterator>
-void iterator insert(const_iterator position, InputIterator first, InputIterator last);
-
-void iterator insert(const_iterator position, initializer_list<T>);
-
    - -

    -23.3.4.3 [list.modifiers] change return type from void to iterator on following declarations: -

    - -
    void iterator insert(const_iterator position, size_type n, const T& x);
-
-template <class InputIterator>
-  void iterator insert(const_iterator position, InputIterator first, InputIterator last);
-
    - -

    -Add the following (missing) declaration -

    - -
    iterator insert(const_iterator position, initializer_list<T>);
-
    - -

    -p2 23.3.6 [vector] -

    - -

    -Update class definition, change return type from void to iterator: -

    - -
    void iterator insert(const_iterator position, T&& x);
-
-void iterator insert(const_iterator position, size_type n, const T& x);
-
-template <class InputIterator>
-  void iterator insert(const_iterator position, InputIterator first, InputIterator last);
-
-void iterator insert(const_iterator position, initializer_list<T>);
-
    - -

    -23.3.6.4 [vector.modifiers] change return type from void to iterator on following declarations: -

    - -
    void iterator insert(const_iterator position, size_type n, const T& x);
-
-template <class InputIterator>
-  void iterator insert(const_iterator position, InputIterator first, InputIterator last);
-
    - -

    -Add the following (missing) declaration -

    - -
    iterator insert(const_iterator position, initializer_list<T>);
-
    - - -

    -p1 23.3.7 [vector.bool] Update class definition, change return type from void to iterator: -

    - -
    void iterator insert (const_iterator position, size_type n, const bool& x);
-
-template <class InputIterator>
-  void iterator insert(const_iterator position, InputIterator first, InputIterator last);
-
-  void iterator insert(const_iterator position, initializer_list<bool> il);
-
    - -

    -p5 21.4 [basic.string] Update class definition, change return type from void to iterator: -

    - -
    void iterator insert(const_iterator p, size_type n, charT c);
-
-template<class InputIterator>
-  void iterator insert(const_iterator p, InputIterator first, InputIterator last);
-
-void iterator insert(const_iterator p, initializer_list<charT>);
-
    - -

    -p13 21.4.6.4 [string::insert] change return type from void to iterator: -

    - -
    void iterator insert(const_iterator p, size_type n, charT c);
-
    - -

    -Add paragraph: -

    - -
    -Returns: an iterator which refers to the copy of the first inserted -character, or p if n == 0.
    -

    -p15 21.4.6.4 [string::insert] change return type from void to iterator: -

    - -
    template<class InputIterator>
-  void iterator insert(const_iterator p, InputIterator first, InputIterator last);
-
    - -

    -Add paragraph: -

    - -
    -Returns: an iterator which refers to the copy of the first inserted -character, or p if first == last. -
    - -

    -p17 21.4.6.4 [string::insert] change return type from void to iterator: -

    - -
    void iterator insert(const_iterator p, initializer_list<charT> il);
-
    - -

    -Add paragraph: -

    - -
    -Returns: an iterator which refers to the copy of the first inserted -character, or p if il is empty. -
    - -

    Rationale:

    +

    20.3.1 [operators] paragraph 10 already specifies the semantics. +That paragraph says that, if declarations of operator!=, operator>, +operator<=, and operator>= appear without definitions, they are +defined as specified in 20.3.1 [operators]. There should be no user +confusion, since that paragraph happens to immediately precede the +specification of pair.

    -

    [ -The following was the C++98/03 rationale and does not necessarily apply to the -proposed resolution in the C++0X time frame: -]

    - - -
    -

    The LWG believes this was an intentional design decision and so is -not a defect. It may be worth revisiting for the next standard.

    -

    299. Incorrect return types for iterator dereference

    -

    Section: 24.2.5 [bidirectional.iterators], 24.2.6 [random.access.iterators] Status: Open - Submitter: John Potter Opened: 2001-01-22 Last modified: 2009-07-28

    +

    Section: 24.2.4 [bidirectional.iterators], 24.2.5 [random.access.iterators] Status: Open + Submitter: John Potter Opened: 2001-01-22 Last modified: 2009-10-26

    View all other issues in [bidirectional.iterators].

    View all issues with Open status.

    Discussion:

    -In section 24.2.5 [bidirectional.iterators], +In section 24.2.4 [bidirectional.iterators], Table 75 gives the return type of *r-- as convertible to T. This is not consistent with Table 74 which gives the return type of *r++ as T&. *r++ = t is valid while *r-- = t is invalid.

    -In section 24.2.6 [random.access.iterators], +In section 24.2.5 [random.access.iterators], Table 76 gives the return type of a[n] as convertible to T. This is not consistent with the semantics of *(a + n) which returns T& by Table 74. *(a + n) = t is valid while a[n] = t is invalid. @@ -1692,6 +1400,40 @@ operational semantics as *(a + n) = t. ]

    +

    [ +2009-09-18 Alisdair adds: +]

    + + +
    +

    +Why can't we write through the reference returned from operator[] on a +random access iterator? +

    + +

    +Recommended solution: +

    + +

    +In table Table 104 -- Random access iterator requirements, replace +

    + +
    +a[n] : convertible to const T & +T& if X is mutable, otherwise convertible to const T& +
    +
    + +

    [ +2009-10 Santa Cruz: +]

    + + +
    +Leave Open. Alisdair to spearhead a paper on revivification. +
    +

    Proposed resolution:

    @@ -1725,7 +1467,7 @@ San Francisco:
    Solved by -N2758. +N2758.
    @@ -1736,10 +1478,10 @@ Solved by

    397. ostream::sentry dtor throws exceptions

    -

    Section: 27.7.2.4 [ostream::sentry] Status: Review - Submitter: Martin Sebor Opened: 2003-01-05 Last modified: 2009-07-14

    +

    Section: 27.7.2.4 [ostream::sentry] Status: Open + Submitter: Martin Sebor Opened: 2003-01-05 Last modified: 2009-10-20

    View all other issues in [ostream::sentry].

    -

    View all issues with Review status.

    +

    View all issues with Open status.

    Discussion:

    17.4.4.8, p3 prohibits library dtors from throwing exceptions. @@ -1788,6 +1530,25 @@ Move to Review. Add "Throws: nothing" to the specification of ostream::sentry::~

    +

    [ +2009-10-13 Daniel adds: +]

    + + +
    +The proposed resolution of 835 is written to match the outcome +of this issue. +
    + +

    [ +2009 Santa Cruz: +]

    + + +
    +Move to Open. Our intent is to solve this issue with 835. +
    +

    Proposed resolution:

    @@ -1816,11 +1577,11 @@ is true, calls os.flush().

    408. Is vector<reverse_iterator<char*> > forbidden?

    -

    Section: 24.2 [iterator.concepts] Status: Review - Submitter: Nathan Myers Opened: 2003-06-03 Last modified: 2009-07-31

    -

    View other active issues in [iterator.concepts].

    -

    View all other issues in [iterator.concepts].

    -

    View all issues with Review status.

    +

    Section: 24.2 [iterator.requirements] Status: Open + Submitter: Nathan Myers Opened: 2003-06-03 Last modified: 2009-11-03

    +

    View other active issues in [iterator.requirements].

    +

    View all other issues in [iterator.requirements].

    +

    View all issues with Open status.

    Discussion:

    I've been discussing iterator semantics with Dave Abrahams, and a @@ -1828,7 +1589,7 @@ surprise has popped up. I don't think this has been discussed before.

    -24.2 [iterator.concepts] says that the only operation that can be performed on "singular" +X [iterator.concepts] says that the only operation that can be performed on "singular" iterator values is to assign a non-singular value to them. (It doesn't say they can be destroyed, and that's probably a defect.) Some implementations have taken this to imply that there is no need @@ -1926,7 +1687,7 @@ are default-initialized, and it should explicitly allow destroying any iterator value, singular or not, default-initialized or not.

    -

    Related issues: 407, 1012

    +

    Related issues: 407, 1012

    [ We don't want to require all singular iterators to be copyable, because that is not the case for pointers. However, default @@ -1955,18 +1716,18 @@ resolved. That just leaves copying (with moving implied).

    -This is related to LWG 1012. +This is related to LWG 1012.

    -Note that there is a bug in the proposed resolution to LWG 1012. The +Note that there is a bug in the proposed resolution to LWG 1012. The change to [reverse.iter.con] should be modified so that the word "default" in the second sentence of the Effects clause is replaced by "value."

    -We believe that the proposed fix to LWG 1012 (now corrected) is +We believe that the proposed fix to LWG 1012 (now corrected) is sufficient to solve the problem for reverse_iterator. However, Alisdair -pointed out that LWG 1012 does not solve the general problem for authors +pointed out that LWG 1012 does not solve the general problem for authors of iterator adaptors.

    @@ -1984,12 +1745,38 @@ Move to Review after Alisdair updates the wording. ]

    +

    [ +2009-08-17 Alisdair and Daniel collaborate on slightly revised wording. +This issue depends upon 724 +]

    + + +

    [ +2009-10-14 Daniel adds: +]

    + + +
    +There is a clear dependency on 1213, because the term "singular", +which is used as part of the resolution, is not properly defined yet. +
    + +

    [ +2009-10 Santa Cruz: +]

    + + +
    +Moved to Open. Alisdair will provide improved wording to make +this have "value semantics" and otherwise behave like a valid iterator. +
    +

    Proposed resolution:

    -Add a new paragrpah to Iterator concepts 24.2 [iterator.concepts] after para 5 (the one -describing singular iterators) +Add a new paragrpah to Iterator concepts 24.2 [iterator.requirements] after para 5 (the one describing +singular iterators)

    @@ -2011,8 +1798,9 @@ Dereferenceable values are always non-singular.

    After value-initialization, any iterator that satisfies the -DefaultConstructible concept shall not introduce undefined behaviour -when used the source of a copy or move operation, even if it would +DefaultConstructible requirements ([defaultconstructible]) shall not introduce undefined behaviour +when used as the +source of a copy or move operation, even if it would otherwise be singular. [Note: This guarantee is not offered for default-initialization (8.5 [dcl.init]), although the distinction only matters for types with trivial default constructors such as pointers. — @@ -2027,128 +1815,10 @@ matters for types with trivial default constructors such as pointers. — -

    -

    419. istream extractors not setting failbit if eofbit is already set

    -

    Section: 27.7.1.1.3 [istream::sentry] Status: Ready - Submitter: Martin Sebor Opened: 2003-09-18 Last modified: 2009-07-14

    -

    View all other issues in [istream::sentry].

    -

    View all issues with Ready status.

    -

    Discussion:

    -

    - -27.7.1.1.3 [istream::sentry], p2 says that istream::sentry ctor prepares for input if is.good() -is true. p4 then goes on to say that the ctor sets the sentry::ok_ member to -true if the stream state is good after any preparation. 27.7.1.2.1 [istream.formatted.reqmts], p1 then -says that a formatted input function endeavors to obtain the requested input -if the sentry's operator bool() returns true. - -Given these requirements, no formatted extractor should ever set failbit if -the initial stream rdstate() == eofbit. That is contrary to the behavior of -all implementations I tested. The program below prints out - -eof = 1, fail = 0 -eof = 1, fail = 1 - -on all of them. -

    -
    -#include <sstream>
-#include <cstdio>
-
-int main()
-{
-    std::istringstream strm ("1");
-
-    int i = 0;
-
-    strm >> i;
-
-    std::printf ("eof = %d, fail = %d\n",
-                 !!strm.eof (), !!strm.fail ());
-
-    strm >> i;
-
-    std::printf ("eof = %d, fail = %d\n",
-                 !!strm.eof (), !!strm.fail ());
-}
-
-
    -

    -
    - -Comments from Jerry Schwarz (c++std-lib-11373): -
    - -Jerry Schwarz wrote: -
    - -I don't know where (if anywhere) it says it in the standard, but the -formatted extractors are supposed to set failbit if they don't extract -any characters. If they didn't then simple loops like -
    - -while (cin >> x); -
    - -would loop forever. -
    - -Further comments from Martin Sebor: -
    - -The question is which part of the extraction should prevent this from happening -by setting failbit when eofbit is already set. It could either be the sentry -object or the extractor. It seems that most implementations have chosen to -set failbit in the sentry [...] so that's the text that will need to be -corrected. - -

    -

    -Pre Berlin: This issue is related to 342. If the sentry -sets failbit when it finds eofbit already set, then -you can never seek away from the end of stream. -

    -

    Kona: Possibly NAD. If eofbit is set then good() will return false. We - then set ok to false. We believe that the sentry's - constructor should always set failbit when ok is false, and - we also think the standard already says that. Possibly it could be - clearer.

    - - -

    [ -2009-07 Frankfurt -]

    - - -
    -Moved to Ready. -
    - - - -

    Proposed resolution:

    -

    -Change 27.7.1.1.3 [istream::sentry], p2 to: -

    - -
    -
    explicit sentry(basic_istream<charT,traits>& is , bool noskipws = false);
    -

    --2- Effects: If is.good() is true -false, calls is.setstate(failbit). -Otherwise prepares for formatted or unformatted input. ... -

    -
    - - - - - -

    427. stage 2 and rationale of DR 221

    Section: 22.4.2.1.2 [facet.num.get.virtuals] Status: Open - Submitter: Martin Sebor Opened: 2003-09-18 Last modified: 2009-07-14

    + Submitter: Martin Sebor Opened: 2003-09-18 Last modified: 2009-10-26

    View other active issues in [facet.num.get.virtuals].

    View all other issues in [facet.num.get.virtuals].

    View all issues with Open status.

    @@ -2233,18 +1903,311 @@ Daniel volunteered to provide wording.

    +

    [ +2009-09-19 Daniel provided wording. +]

    + + +

    [ +2009-10 Santa Cruz: +]

    + + +
    +Leave as Open. Alisdair and/or Tom will provide wording based on discussions. +We want to clearly state that streams and locales work just on char +and wchar_t (except where otherwise specified). +
    +

    Proposed resolution:

    +
      +
    1. +

      +Change 22.3.1.1.1 [locale.category]/6: +

      + +
      +[..] A template formal parameter with name C represents the set of all possible +specializations on a char or wchar_t parameter that satisfies +the requirements for a character on which any of the iostream components +can be instantiated. [..] +
      +
      2. + +
    2. +

      +Add the following sentence to the end of 22.4.2 [category.numeric]/2: +

      + +
      +[..] These specializations refer to [..], and also for the ctype<> facet to +perform character classification. Implementations are encouraged +but not required to use the char_traits<charT> functions for all +comparisons and assignments of characters of type charT that do +not belong to the set of required specializations. +
      +
      3. + +
    3. +

      +Change 22.4.2.1.2 [facet.num.get.virtuals]/3: +

      + +
      +

      +Stage 2: If in==end then stage 2 terminates. Otherwise a charT is taken +from in and local variables are initialized as if by +

      + +
      char_type ct = *in;
+using tr = char_traits<char_type>;
+const char_type* pos = tr::find(atoms, sizeof(src) - 1, ct);
+char c = src[find(atoms, atoms + sizeof(src) - 1, ct) - atoms
+             pos ? pos - atoms : sizeof(src) - 1];
+if (tr::eq(ct, ct == use_facet<numpunct<charT>(loc).decimal_point()))
+    c = '.';
+bool discard =
+    tr::eq(ct, ct == use_facet<numpunct<charT>(loc).thousands_sep())
+    && use_facet<numpunct<charT> >(loc).grouping().length() != 0;
+
      + +

      +where the values src and atoms are defined as if by: [..] +

      +
      + +

      +[Remark of the author: I considered to replace the initialization +"char_type ct = *in;" +by the sequence "char_type ct; tr::assign(ct, *in);", but decided +against it, because +it is a copy-initialization context, not an assignment] +

      +
      4. + +
    4. +

      +Add the following sentence to the end of 22.4.5 [category.time]/1: +

      + +
      +[..] Their members use [..] , to determine formatting details. +Implementations are encouraged but not required to use the +char_traits<charT> functions for all comparisons and assignments +of characters of type charT that do +not belong to the set of required specializations. +
      +
      5. + +
    5. +

      +Change 22.4.5.1.1 [locale.time.get.members]/8 bullet 4: +

      + +
        +
      • +The next element of fmt is equal to '%' For the next element c +of fmt char_traits<char_type>::eq(c, use_facet<ctype<char_type>>(f.getloc()).widen('%')) == true, +[..] +
        • +
      +
      6. + +
    6. +

      +Add the following sentence to the end of 22.4.6 [category.monetary]/2: +

      + +
      +Their members use [..] to determine formatting details. +Implementations are encouraged but not required to use the +char_traits<charT> functions for all comparisons and assignments +of characters of type charT that do +not belong to the set of required specializations. +
      +
      7. + +
    7. +

      +Change 22.4.6.1.2 [locale.money.get.virtuals]/4: +

      + +
      +

      +[..] The value units is produced as if by: +

      + +
      for (int i = 0; i < n; ++i)
+  buf2[i] = src[char_traits<charT>::find(atoms, atoms+sizeof(src), buf1[i]) - atoms];
+buf2[n] = 0;
+sscanf(buf2, "%Lf", &units);
+
      +
      +
      8. + +
    8. +

      +Change 22.4.6.2.2 [locale.money.put.virtuals]/1: +

      + +
      +[..] for character buffers buf1 and buf2. If for the first +character c +in digits or buf2 is equal to +ct.widen('-')char_traits<charT>::eq(c, +ct.widen('-')) == true, [..] +
      +
      9. + +
    9. +

      +Add a footnote to the first sentence of 27.7.1.2.2 [istream.formatted.arithmetic]/1: +

      + +
      +

      +As in the case of the inserters, these extractors depend on the locale's +num_get<> (22.4.2.1) object to perform parsing the input stream +data.(footnote) [..] +

      + +

      + +footnote) If the traits of the input stream has different semantics for lt(), +eq(), and assign() than char_traits<char_type>, this may give surprising +results. + +

      +
      +
      10. + +
    10. +

      +Add a footnote to the second sentence of 27.7.2.6.2 [ostream.inserters.arithmetic]/1: +

      + +
      +

      +Effects: The classes num_get<> and +num_put<> handle locale-dependent numeric formatting and +parsing. These inserter functions use the imbued locale value to perform +numeric formatting.(footnote) [..] +

      + +

      + +footnote) If the traits of the output stream has different semantics for lt(), +eq(), and assign() than char_traits<char_type>, this may give surprising +results. + +

      +
      +
      11. + +
    11. +

      +Add a footnote after the first sentence of 27.7.4 [ext.manip]/4: +

      + +
      +

      +Returns: An object of unspecified type such that if in is an object of type +basic_istream<charT, traits> then the expression in >> get_money(mon, intl) +behaves as if it called f(in, mon, intl), where the function f is defined +as:(footnote) [..] +

      + +

      + +footnote) If the traits of the input stream has different semantics for lt(), +eq(), and assign() than char_traits<char_type>, this may give surprising +results. + +

      +
      +
      12. + +
    12. +

      +Add a footnote after the first sentence of 27.7.4 [ext.manip]/5: +

      + +
      +

      +Returns: An object of unspecified type such that if out is an object of type +basic_ostream<charT, traits> then the expression out << put_money(mon, intl) +behaves as a formatted input function that calls f(out, mon, intl), where the +function f is defined as:(footnote) [..] +

      + +

      + +footnote) If the traits of the output stream has different semantics for lt(), +eq(), and assign() than char_traits<char_type>, this may give surprising +results. + +

      +
      +
      13. + +
    13. +

      +13) Add a footnote after the first sentence of 27.7.4 [ext.manip]/8: +

      + +
      +

      +Returns: An object of unspecified type such that if in is an +object of type basic_istream<charT, traits> then the expression +in >>get_time(tmb, fmt) behaves as if it called f(in, tmb, fmt), +where the function f is defined as:(footnote) [..] +

      + +

      + +footnote) If the traits of the input stream has different semantics for lt(), +eq(), and assign() than char_traits<char_type>, this may give surprising +results. + +

      +
      +
      14. + +
    14. +

      +Add a footnote after the first sentence of 27.7.4 [ext.manip]/10: +

      + +
      +

      +Returns: An object of unspecified type such that if out is an object of type +basic_ostream<charT, traits> then the expression out <<put_time(tmb, fmt) +behaves as if it called f(out, tmb, fmt), where the function f is defined +as:(footnote) [..] +

      + +

      + +footnote) If the traits of the output stream has different semantics for lt(), +eq(), and assign() than char_traits<char_type>, this may give surprising +results. + +

      +
      +
      15. +
    +

    430. valarray subset operations

    -

    Section: 26.6.2.4 [valarray.sub] Status: Ready - Submitter: Martin Sebor Opened: 2003-09-18 Last modified: 2009-07-14

    -

    View all issues with Ready status.

    +

    Section: 26.6.2.4 [valarray.sub] Status: Open + Submitter: Martin Sebor Opened: 2003-09-18 Last modified: 2009-11-04

    +

    View all issues with Open status.

    Discussion:

    The standard fails to specify the behavior of valarray::operator[](slice) @@ -2286,6 +2249,16 @@ Move to Ready.

    +

    [ +2009-11-04 Pete opens: +]

    + + +
    +The resolution to LWG issue 430 has not been applied --- there have been +changes to the underlying text, and the resolution needs to be reworked. +
    +

    Proposed resolution:

    @@ -2424,112 +2397,12 @@ const size_t vi[] = {7, 5, 2, 3, 8}; -
    -

    431. Swapping containers with unequal allocators

    -

    Section: X [allocator.requirements], 25 [algorithms] Status: Open - Submitter: Matt Austern Opened: 2003-09-20 Last modified: 2009-07-17

    -

    View other active issues in [allocator.requirements].

    -

    View all other issues in [allocator.requirements].

    -

    View all issues with Open status.

    -

    Discussion:

    -

    Clause X [allocator.requirements] paragraph 4 says that implementations - are permitted to supply containers that are unable to cope with - allocator instances and that container implementations may assume - that all instances of an allocator type compare equal. We gave - implementers this latitude as a temporary hack, and eventually we - want to get rid of it. What happens when we're dealing with - allocators that don't compare equal? -

    - -

    In particular: suppose that v1 and v2 are both - objects of type vector<int, my_alloc> and that - v1.get_allocator() != v2.get_allocator(). What happens if - we write v1.swap(v2)? Informally, three possibilities:

    - -

    1. This operation is illegal. Perhaps we could say that an - implementation is required to check and to throw an exception, or - perhaps we could say it's undefined behavior.

    -

    2. The operation performs a slow swap (i.e. using three - invocations of operator=, leaving each allocator with its - original container. This would be an O(N) operation.

    -

    3. The operation swaps both the vectors' contents and their - allocators. This would be an O(1) operation. That is:

    -
    - 
        my_alloc a1(...);
-    my_alloc a2(...);
-    assert(a1 != a2);
-
-    vector<int, my_alloc> v1(a1);
-    vector<int, my_alloc> v2(a2);
-    assert(a1 == v1.get_allocator());
-    assert(a2 == v2.get_allocator());
-
-    v1.swap(v2);
-    assert(a1 == v2.get_allocator());
-    assert(a2 == v1.get_allocator());
-
    -
    - -

    [Kona: This is part of a general problem. We need a paper - saying how to deal with unequal allocators in general.]

    - - -

    [pre-Sydney: Howard argues for option 3 in -N1599. -]

    - - -

    [ -2007-01-12, Howard: This issue will now tend to come up more often with move constructors -and move assignment operators. For containers, these members transfer resources (i.e. -the allocated memory) just like swap. -]

    - - -

    [ -Batavia: There is agreement to overload the container swap on the allocator's Swappable -requirement using concepts. If the allocator supports Swappable, then container's swap will -swap allocators, else it will perform a "slow swap" using copy construction and copy assignment. -]

    - - -

    [ -2009-04-28 Pablo adds: -]

    - -
    -Fixed in -N2525. -I argued for marking this Tentatively-Ready right after Bellevue, -but there was a concern that -N2525 -would break in the presence of the RVO. (That breakage had nothing to do with -swap, but never-the-less). I addressed that breakage in in -N2840 -(Summit) by means of a non-normative reference: - -
    -[Note: in situations where the copy constructor for a container is elided, -this function is not called. The behavior in these cases is as if -select_on_container_copy_construction returned x — end note] -
    - -
    - - - -

    Proposed resolution:

    - - - - -

    446. Iterator equality between different containers

    -

    Section: 24.2 [iterator.concepts], 23.2 [container.requirements] Status: Open - Submitter: Andy Koenig Opened: 2003-12-16 Last modified: 2009-07-14

    -

    View other active issues in [iterator.concepts].

    -

    View all other issues in [iterator.concepts].

    +

    Section: 24.2 [iterator.requirements], 23.2 [container.requirements] Status: Open + Submitter: Andy Koenig Opened: 2003-12-16 Last modified: 2009-11-03

    +

    View other active issues in [iterator.requirements].

    +

    View all other issues in [iterator.requirements].

    View all issues with Open status.

    Discussion:

    @@ -2562,509 +2435,41 @@ reachability. Daniel volunteered to work on this. - - -

    Proposed resolution:

    - - - - - - -
    -

    458. 24.1.5 contains unintended limitation for operator-

    -

    Section: 24.2.6 [random.access.iterators] Status: Open - Submitter: Daniel Frey Opened: 2004-02-27 Last modified: 2009-07-17

    -

    View other active issues in [random.access.iterators].

    -

    View all other issues in [random.access.iterators].

    -

    View all issues with Open status.

    -

    Discussion:

    -

    -In 24.1.5 [lib.random.access.iterators], table 76 the operational -semantics for the expression "r -= n" are defined as "return r += -n". -This means, that the expression -n must be valid, which is not the case -for unsigned types. -

    -

    [ -Sydney: Possibly not a real problem, since difference type is required -to be a signed integer type. However, the wording in the standard may -be less clear than we would like. +2009-09-20 Daniel provided wording. ]

    [ -Post Summit Alisdair adds: +2009-10 Santa Cruz: ]

    -

    -This issue refers to a requirements table we have removed. -

    -

    -The issue might now relate to 24.2.6 [random.access.iterators] p5. -However, the rationale in the issue already recognises that the -difference_type must be signed, so this really looks NAD. -

    -
    - -

    [ -Batavia (2009-05): -]

    - -
    -

    -We agree with Alisdair's observations. -

    -

    -Move to NAD. -

    -
    - -

    [ -2009-07 Frankfurt: -]

    - - -
    -

    -Need to look at again without concepts. -

    -

    -There was a question about this phrase in the discussion: "the -expression -n must be valid, which is not the case for unsigned types." -If n is an object ofthe iterator difference_type (eg ptrdiff_t), then it -is never unsigned. -

    +Leave as Open. Alisdair has volunteered to refine the wording.

    Proposed resolution:

    -To remove this limitation, I suggest to change the -operational semantics for this column to: -

    -
        { Distance m = n;
-      if (m >= 0)
-        while (m--) --r;
-      else
-        while (m++) ++r;
-      return r; }
-
    - - - - - - -
    -

    463. auto_ptr usability issues

    -

    Section: D.9.1 [auto.ptr] Status: Open - Submitter: Rani Sharoni Opened: 2003-12-07 Last modified: 2009-07-14

    -

    View all other issues in [auto.ptr].

    -

    View all issues with Open status.

    -

    Discussion:

    - -

    -TC1 CWG DR #84 effectively made the template<class Y> operator auto_ptr<Y>() -member of auto_ptr (20.4.5.3/4) obsolete. -

    - -

    -The sole purpose of this obsolete conversion member is to enable copy -initialization base from r-value derived (or any convertible types like -cv-types) case: -

    -
    #include <memory>
-using std::auto_ptr;
-
-struct B {};
-struct D : B {};
-
-auto_ptr<D> source();
-int sink(auto_ptr<B>);
-int x1 = sink( source() ); // #1 EDG - no suitable copy constructor
-
    - -

    -The excellent analysis of conversion operations that was given in the final -auto_ptr proposal -(http://anubis.dkuug.dk/jtc1/sc22/wg21/docs/papers/1997/N1128.pdf) -explicitly specifies this case analysis (case 4). DR #84 makes the analysis -wrong and actually comes to forbid the loophole that was exploited by the -auto_ptr designers. -

    - -

    -I didn't encounter any compliant compiler (e.g. EDG, GCC, BCC and VC) that -ever allowed this case. This is probably because it requires 3 user defined -conversions and in fact current compilers conform to DR #84. -

    - -

    -I was surprised to discover that the obsolete conversion member actually has -negative impact of the copy initialization base from l-value derived -case:

    -
    auto_ptr<D> dp;
-int x2 = sink(dp); // #2 EDG - more than one user-defined conversion applies
-
    - -

    -I'm sure that the original intention was allowing this initialization using -the template<class Y> auto_ptr(auto_ptr<Y>& a) constructor (20.4.5.1/4) but -since in this copy initialization it's merely user defined conversion (UDC) -and the obsolete conversion member is UDC with the same rank (for the early -overloading stage) there is an ambiguity between them. -

    - -

    -Removing the obsolete member will have impact on code that explicitly -invokes it: -

    -
    int y = sink(source().operator auto_ptr<B>());
-
    - -

    -IMHO no one ever wrote such awkward code and the reasonable workaround for -#1 is: -

    -
    int y = sink( auto_ptr<B>(source()) );
-
    - -

    -I was even more surprised to find out that after removing the obsolete -conversion member the initialization was still ill-formed: -int x3 = sink(dp); // #3 EDG - no suitable copy constructor -

    - -

    -This copy initialization semantically requires copy constructor which means -that both template conversion constructor and the auto_ptr_ref conversion -member (20.4.5.3/3) are required which is what was explicitly forbidden in -DR #84. This is a bit amusing case in which removing ambiguity results with -no candidates. -

    - -

    -I also found exception safety issue with auto_ptr related to auto_ptr_ref: -

    -
    int f(auto_ptr<B>, std::string);
-auto_ptr<B> source2();
-
-// string constructor throws while auto_ptr_ref
-// "holds" the pointer
-int x4 = f(source2(), "xyz"); // #4
-
    - -

    -The theoretic execution sequence that will cause a leak: -

    -
      -
    1. call auto_ptr<B>::operator auto_ptr_ref<B>()
      2. -
    2. call string::string(char const*) and throw
      3. -
    - -

    -According to 20.4.5.3/3 and 20.4.5/2 the auto_ptr_ref conversion member -returns auto_ptr_ref<Y> that holds *this and this is another defect since -the type of *this is auto_ptr<X> where X might be different from Y. Several -library vendors (e.g. SGI) implement auto_ptr_ref<Y> with Y* as member which -is much more reasonable. Other vendor implemented auto_ptr_ref as -defectively required and it results with awkward and catastrophic code: -int oops = sink(auto_ptr<B>(source())); // warning recursive on all control -paths -

    - -

    -Dave Abrahams noticed that there is no specification saying that -auto_ptr_ref copy constructor can't throw. -

    - -

    -My proposal comes to solve all the above issues and significantly simplify -auto_ptr implementation. One of the fundamental requirements from auto_ptr -is that it can be constructed in an intuitive manner (i.e. like ordinary -pointers) but with strict ownership semantics which yield that source -auto_ptr in initialization must be non-const. My idea is to add additional -constructor template with sole propose to generate ill-formed, diagnostic -required, instance for const auto_ptr arguments during instantiation of -declaration. This special constructor will not be instantiated for other -types which is achievable using 14.8.2/2 (SFINAE). Having this constructor -in hand makes the constructor template<class Y> auto_ptr(auto_ptr<Y> const&) -legitimate since the actual argument can't be const yet non const r-value -are acceptable. -

    - -

    -This implementation technique makes the "private auxiliary class" -auto_ptr_ref obsolete and I found out that modern C++ compilers (e.g. EDG, -GCC and VC) consume the new implementation as expected and allow all -intuitive initialization and assignment cases while rejecting illegal cases -that involve const auto_ptr arguments. -

    - -

    The proposed auto_ptr interface:

    - -
    namespace std {
-    template<class X> class auto_ptr {
-    public:
-        typedef X element_type;
-
-        // 20.4.5.1 construct/copy/destroy:
-        explicit auto_ptr(X* p=0) throw();
-        auto_ptr(auto_ptr&) throw();
-        template<class Y> auto_ptr(auto_ptr<Y> const&) throw();
-        auto_ptr& operator=(auto_ptr&) throw();
-        template<class Y> auto_ptr& operator=(auto_ptr<Y>) throw();
-        ~auto_ptr() throw();
-
-        // 20.4.5.2 members:
-        X& operator*() const throw();
-        X* operator->() const throw();
-        X* get() const throw();
-        X* release() throw();
-        void reset(X* p=0) throw();
-
-    private:
-        template<class U>
-        auto_ptr(U& rhs, typename
-unspecified_error_on_const_auto_ptr<U>::type = 0);
-    };
-}
-
    - -

    -One compliant technique to implement the unspecified_error_on_const_auto_ptr -helper class is using additional private auto_ptr member class template like -the following: -

    -
    template<typename T> struct unspecified_error_on_const_auto_ptr;
-
-template<typename T>
-struct unspecified_error_on_const_auto_ptr<auto_ptr<T> const>
-{ typedef typename auto_ptr<T>::const_auto_ptr_is_not_allowed type; };
-
    - -

    -There are other techniques to implement this helper class that might work -better for different compliers (i.e. better diagnostics) and therefore I -suggest defining its semantic behavior without mandating any specific -implementation. IMO, and I didn't found any compiler that thinks otherwise, -14.7.1/5 doesn't theoretically defeat the suggested technique but I suggest -verifying this with core language experts. -

    - -

    Further changes in standard text:

    -

    Remove section 20.4.5.3

    - -

    Change 20.4.5/2 to read something like: -Initializing auto_ptr<X> from const auto_ptr<Y> will result with unspecified -ill-formed declaration that will require unspecified diagnostic.

    - -

    Change 20.4.5.1/4,5,6 to read:

    - -
    template<class Y> auto_ptr(auto_ptr<Y> const& a) throw();
    -

    4 Requires: Y* can be implicitly converted to X*.

    -

    5 Effects: Calls const_cast<auto_ptr<Y>&>(a).release().

    -

    6 Postconditions: *this holds the pointer returned from a.release().

    - -

    Change 20.4.5.1/10

    -
    template<class Y> auto_ptr& operator=(auto_ptr<Y> a) throw();
-
    -

    -10 Requires: Y* can be implicitly converted to X*. The expression delete -get() is well formed. -

    - -

    LWG TC DR #127 is obsolete.

    - -

    -Notice that the copy constructor and copy assignment operator should remain -as before and accept non-const auto_ptr& since they have effect on the form -of the implicitly declared copy constructor and copy assignment operator of -class that contains auto_ptr as member per 12.8/5,10: -

    -
    struct X {
-    // implicit X(X&)
-    // implicit X& operator=(X&)
-    auto_ptr<D> aptr_;
-};
-
    - -

    -In most cases this indicates about sloppy programming but preserves the -current auto_ptr behavior. -

    - -

    -Dave Abrahams encouraged me to suggest fallback implementation in case that -my suggestion that involves removing of auto_ptr_ref will not be accepted. -In this case removing the obsolete conversion member to auto_ptr<Y> and -20.4.5.3/4,5 is still required in order to eliminate ambiguity in legal -cases. The two constructors that I suggested will co exist with the current -members but will make auto_ptr_ref obsolete in initialization contexts. -auto_ptr_ref will be effective in assignment contexts as suggested in DR -#127 and I can't see any serious exception safety issues in those cases -(although it's possible to synthesize such). auto_ptr_ref<X> semantics will -have to be revised to say that it strictly holds pointer of type X and not -reference to an auto_ptr for the favor of cases in which auto_ptr_ref<Y> is -constructed from auto_ptr<X> in which X is different from Y (i.e. assignment -from r-value derived to base). -

    - -

    [Redmond: punt for the moment. We haven't decided yet whether we - want to fix auto_ptr for C++-0x, or remove it and replace it with - move_ptr and unique_ptr.]

    - - -

    [ -Oxford 2007: Recommend NAD. We're just going to deprecate it. It still works for simple use cases -and people know how to deal with it. Going forward unique_ptr is the recommended -tool. -]

    - - -

    [ -2007-11-09: Reopened at the request of David Abrahams, Alisdair Meredith and Gabriel Dos Reis. -]

    - - -

    [ -2009-07 Frankfurt -]

    - - -
    -This is a complicated issue, so we agreed to defer discussion until -later in the week so that interested parties can read up on it. -
    - - - -

    Proposed resolution:

    -

    -Change the synopsis in D.9.1 [auto.ptr]: -

    - -
    namespace std { 
-  template <class Y> struct auto_ptr_ref {};
-
-  // exposition only
-  template <class T> struct constant_object;
-
-  // exposition only
-  template <class T>
-  struct cannot_transfer_ownership_from
-    : constant_object<T> {};
-
-  template <class X> class auto_ptr { 
-  public: 
-    typedef X element_type; 
-
-    // D.9.1.1 construct/copy/destroy: 
-    explicit auto_ptr(X* p =0) throw(); 
-    auto_ptr(auto_ptr&) throw(); 
-    template<class Y> auto_ptr(auto_ptr<Y> const&) throw(); 
-    auto_ptr& operator=(auto_ptr&) throw(); 
-    template<class Y> auto_ptr& operator=(auto_ptr<Y>&) throw();
-    auto_ptr& operator=(auto_ptr_ref<X> r) throw();
-    ~auto_ptr() throw(); 
-
-    // D.9.1.2 members: 
-    X& operator*() const throw();
-    X* operator->() const throw();
-    X* get() const throw();
-    X* release() throw();
-    void reset(X* p =0) throw();
-
-    // D.9.1.3 conversions:
-    auto_ptr(auto_ptr_ref<X>) throw();
-    template<class Y> operator auto_ptr_ref<Y>() throw();
-    template<class Y> operator auto_ptr<Y>() throw();
-
-    // exposition only
-    template<class U>
-    auto_ptr(U& rhs, typename cannot_transfer_ownership_from<U>::error = 0);
-  }; 
-
-  template <> class auto_ptr<void> 
-  { 
-  public: 
-    typedef void element_type; 
-  }; 
-
-}
-
    - -

    -Remove D.9.1.3 [auto.ptr.conv]. -

    - -

    -Change D.9.1 [auto.ptr], p3: +Insert a new paragraph between 24.2 [iterator.requirements]/7+8:

    -The auto_ptr provides a semantics of strict ownership. An -auto_ptr owns the object it holds a pointer to. Copying an -auto_ptr copies the pointer and transfers ownership to the -destination. If more than one auto_ptr owns the same object at -the same time the behavior of the program is undefined. Templates -constant_object and cannot_transfer_ownership_from, -and the final constructor of auto_ptr are for exposition only. -For any types X and Y, initializing -auto_ptr<X> from const auto_ptr<Y> is -ill-formed, diagnostic required. [Note: The uses of -auto_ptr include providing temporary exception-safety for -dynamically allocated memory, passing ownership of dynamically allocated -memory to a function, and returning dynamically allocated memory from a -function. auto_ptr does not meet the CopyConstructible -and Assignable requirements for Standard Library container -elements and thus instantiating a Standard Library container with an -auto_ptr results in undefined behavior. -- end note] -
    -

    -Change D.9.1.1 [auto.ptr.cons], p5: +[..] The result of the application of functions in the library to invalid +ranges is undefined.

    -
    -
    template<class Y> auto_ptr(auto_ptr<Y> const& a) throw();
-
    -
    -

    -Requires: Y* can be implicitly converted to X*. -

    -

    -Effects: Calls const_cast<auto_ptr<Y>&>(a).release(). -

    -

    -Postconditions: *this holds the pointer returned from a.release(). -

    -
    -
    - -

    -Change D.9.1.1 [auto.ptr.cons], p10: +

    The result of directly or indirectly evaluating any comparison function +or the binary - operator with two iterator values as arguments that +were obtained +from two different ranges r1 and r2 (including their past-the-end values) which +are not subranges of one common range is undefined, unless explicitly +described otherwise.

    -
    -
    template<class Y> auto_ptr& operator=(auto_ptr<Y>& a) throw();
-
    -
    -

    -Requires: Y* can be implicitly converted to X*. -The expression delete get() is well formed. -

    -

    -Effects: Calls reset(a.release()). -

    -

    -Returns: *this. -

    -
    @@ -3074,9 +2479,9 @@ The expression delete get() is well formed.

    471. result of what() implementation-defined

    -

    Section: 18.8.1 [exception] Status: Open - Submitter: Martin Sebor Opened: 2004-06-28 Last modified: 2009-07-30

    -

    View all issues with Open status.

    +

    Section: 18.8.1 [exception] Status: Ready + Submitter: Martin Sebor Opened: 2004-06-28 Last modified: 2009-10-26

    +

    View all issues with Ready status.

    Discussion:

    [lib.exception] specifies the following:

    @@ -3189,6 +2594,38 @@ Pete asks what "the same NTBS" means. Further discussion in the thread starting with c++std-lib-24512. +

    [ +2009-09-24 Niels provided updated wording: +]

    + + +
    +

    +I think the resolution should at least guarantee +that the result of what() is independent of whether the compiler does +copy-elision. And for any class derived from std::excepion that has a +constructor that allows specifying a what_arg, it should make sure that +the text of a user-provided what_arg is preserved, when the object is +copied. Note that all the implementations I've tested already appear to +satisfy the proposed resolution, including MSVC 2008 SP1, Apache +stdcxx-4.2.1, GCC 4.1.2, GCC 4.3.2, and CodeGear C++ 6.13. +

    +

    +The proposed resolution was updated with help from Daniel Krügler; +the update aims to clarify that the proposed postcondition only +applies to homogeneous copying. +

    +
    + +

    [ +2009-10 Santa Cruz: +]

    + + +
    +Moved to Ready after inserting "publicly accessible" in two places. +
    +

    Proposed resolution:

    @@ -3198,35 +2635,55 @@ Change 18.8.1 [exception] to:

    -
    exception(const exception& e) throw();
-exception& operator=(const exception& e) throw();
    +

    +-1- The class exception defines the base class for the types of +objects thrown as exceptions by C++ standard library components, and +certain expressions, to report errors detected during program execution. +

    +

    +Each standard library class T that derives from class +exception shall have a publicly accessible copy constructor and a publicly accessible copy assignment +operator that do not exit with an exception. These member functions +shall preserve the following postcondition: If two objects lhs +and rhs both have dynamic type T, and lhs is a +copy of rhs, then strcmp(lhs.what(), +rhs.what()) == 0. +

    +

    + ... +

    + +
    exception(const exception& rhs) throw();
+exception& operator=(const exception& rhs) throw();
    +

    -4- Effects: Copies an exception object.

    - -5- Remarks: The effects of calling what() after assignment are implementation-defined. + -5- Remarks: The effects of calling what() after assignment +are implementation-defined.

    --5- Throws: Nothing. This also applies -to all standard library-defined classes that derive from exception. -

    -

    --7- Postcondition: strcmp(what(), e.what()) == 0. This also applies -to all standard library-defined classes that derive from exception. +-5- Postcondition: + If *this + and rhs both have dynamic type exception + then strcmp(what(), rhs.what()) == 0.

    +
    +

    473. underspecified ctype calls

    -

    Section: 22.4.1.1 [locale.ctype] Status: Review - Submitter: Martin Sebor Opened: 2004-07-01 Last modified: 2009-07-17

    -

    View all issues with Review status.

    +

    Section: 22.4.1.1 [locale.ctype] Status: Ready + Submitter: Martin Sebor Opened: 2004-07-01 Last modified: 2009-10-21

    +

    View all issues with Ready status.

    Discussion:

    Most ctype member functions come in two forms: one that operates @@ -3305,6 +2762,15 @@ provide wording.

    ]

    +

    [ +2009-10 Santa Cruz: +]

    + + +
    +Move to Ready. +
    +

    Proposed resolution:

    @@ -3319,91 +2785,22 @@ virtual function. - - -
    -

    484. Convertible to T

    -

    Section: 24.2.2 [input.iterators] Status: Open - Submitter: Chris Jefferson Opened: 2004-09-16 Last modified: 2009-07-28

    -

    View all other issues in [input.iterators].

    -

    View all issues with Open status.

    -

    Discussion:

    -

    From comp.std.c++:

    - -

    -I note that given an input iterator a for type T, -then *a only has to be "convertable to T", not actually of type T. -

    - -

    Firstly, I can't seem to find an exact definition of "convertable to T". -While I assume it is the obvious definition (an implicit conversion), I -can't find an exact definition. Is there one?

    - -

    Slightly more worryingly, there doesn't seem to be any restriction on -the this type, other than it is "convertable to T". Consider two input -iterators a and b. I would personally assume that most people would -expect *a==*b would perform T(*a)==T(*b), however it doesn't seem that -the standard requires that, and that whatever type *a is (call it U) -could have == defined on it with totally different symantics and still -be a valid inputer iterator.

    - -

    Is this a correct reading? When using input iterators should I write -T(*a) all over the place to be sure that the object i'm using is the -class I expect?

    - -

    This is especially a nuisance for operations that are defined to be - "convertible to bool". (This is probably allowed so that - implementations could return say an int and avoid an unnessary - conversion. However all implementations I have seen simply return a - bool anyway. Typical implemtations of STL algorithms just write - things like while(a!=b && *a!=0). But strictly - speaking, there are lots of types that are convertible to T but - that also overload the appropriate operators so this doesn't behave - as expected.

    - -

    If we want to make code like this legal (which most people seem to - expect), then we'll need to tighten up what we mean by "convertible - to T".

    - -

    [Lillehammer: The first part is NAD, since "convertible" is - well-defined in core. The second part is basically about pathological - overloads. It's a minor problem but a real one. So leave open for - now, hope we solve it as part of iterator redesign.]

    - - -

    [ -2009-07-28 Reopened by Alisdair. No longer solved by concepts. -]

    - - - - -

    Proposed resolution:

    - -

    Rationale:

    -

    [ -San Francisco: -]

    - - -
    -Solved by -N2758. -
    - - - +

    +We are explicitly not addressing bullet +item #2, thus giving implementors more latitude. Users will have to +override both virtual functions, not just one. +

    485. output iterator insufficiently constrained

    -

    Section: 24.2.3 [output.iterators] Status: Open - Submitter: Chris Jefferson Opened: 2004-10-13 Last modified: 2009-07-21

    +

    Section: 24.2.2 [output.iterators] Status: Ready + Submitter: Chris Jefferson Opened: 2004-10-13 Last modified: 2009-10-26

    View all other issues in [output.iterators].

    -

    View all issues with Open status.

    +

    View all issues with Ready status.

    Discussion:

    The note on 24.1.2 Output iterators insufficiently limits what can be @@ -3446,16 +2843,34 @@ Bill provided wording according to consensus.

    [ -2009-07-21 Alsidair requests change from Review to Open. See thread starting +2009-07-21 Alisdair requests change from Review to Open. See thread starting with c++std-lib-24459 for discussion. ]

    +

    [ +2009-10 Santa Cruz: +]

    + + +
    +Modified wording. Set to Review. +
    + +

    [ +2009-10 Santa Cruz: +]

    + + +
    +Move to Ready after looking at again in a larger group in Santa Cruz. +
    +

    Proposed resolution:

    -Change Table 101 — Output iterator requirements in 24.2.3 [output.iterators]: +Change Table 101 — Output iterator requirements in 24.2.2 [output.iterators]:

    @@ -3499,62 +2914,69 @@ Change Table 101 — Output iterator requirements in 24.2.3 [output.iterator - - + + - - + + - + +Post: r is dereferenceable, unless otherwise specified. r is not required to be incrementable. + + - - - + + + @@ -3565,249 +2987,11 @@ result is not usedusable -
    -

    498. Requirements for partition() and stable_partition() too strong

    -

    Section: 25.4.13 [alg.partitions] Status: Ready - Submitter: Sean Parent, Joe Gottman Opened: 2005-05-04 Last modified: 2009-07-15

    -

    View all issues with Ready status.

    -

    Discussion:

    -

    -Problem: -The iterator requirements for partition() and stable_partition() [25.2.12] -are listed as BidirectionalIterator, however, there are efficient algorithms -for these functions that only require ForwardIterator that have been known -since before the standard existed. The SGI implementation includes these (see -http://www.sgi.com/tech/stl/partition.html -and -http://www.sgi.com/tech/stl/stable_partition.html). -

    - -

    [ -2009-04-30 Alisdair adds: -]

    - - -
    -

    -Now we have concepts this is easier to express! -

    -

    -Proposed resolution: -

    -

    -Add the following signature to: -

    -

    -Header <algorithm> synopsis 25.2 [algorithms.syn]
    -p3 Partitions 25.4.13 [alg.partitions] -

    -
     template<ForwardIterator Iter, Predicate<auto, Iter::value_type> Pred>
-   requires ShuffleIterator<Iter>
-         && CopyConstructible<Pred>
-   Iter partition(Iter first, Iter last, Pred pred);
-
    - -

    -Update p3 Partitions 25.4.13 [alg.partitions]: -

    - -
    -

    -Complexity: At most (last - first)/2 swaps. Exactly last - first -applications of the predicate -are done. - -If Iter satisfies BidirectionalIterator, at most (last - -first)/2 swaps. Exactly last - first applications of the predicate -are done. - -

    -

    -If Iter merely satisfied ForwardIterator at most (last - first) swaps -are done. Exactly (last - first) applications of the predicate are done. -

    -
    - -

    -[Editorial note: I looked for existing precedent in how we might call out -distinct overloads overloads from a set of constrained templates, but there -is not much existing practice to lean on. advance/distance were the only -algorithms I could find, and that wording is no clearer.] -

    - -
    - -

    [ -2009-07 Frankfurt -]

    - - -
    -

    -Hinnant: if you want to partition your std::forward_list, you'll need -partition() to accept ForwardIterators. -

    -

    -No objection to Ready. -

    -

    -Move to Ready. -

    -
    - - - -

    Proposed resolution:

    -

    -Change 25.2.12 from

    -
    template<class BidirectionalIterator, class Predicate> 
-BidirectionalIterator partition(BidirectionalIterato r first, 
-                                BidirectionalIterator last, 
-                                Predicate pred); 
-
    -

    to

    -
    template<class ForwardIterator, class Predicate> 
-ForwardIterator partition(ForwardIterator first, 
-                          ForwardIterator last, 
-                          Predicate pred); 
-
    -

    Change the complexity from

    - -

    -At most (last - first)/2 swaps are done. Exactly (last - first) -applications of the predicate are done. -

    - -

    to

    - -

    -If ForwardIterator is a bidirectional_iterator, at most (last - first)/2 -swaps are done; otherwise at most (last - first) swaps are done. Exactly -(last - first) applications of the predicate are done. -

    - - - -

    Rationale:

    -

    -Partition is a "foundation" algorithm useful in many contexts (like sorting -as just one example) - my motivation for extending it to include forward -iterators is foward_list - without this extension you can't partition an foward_list -(without writing your own partition). Holes like this in the standard -library weaken the argument for generic programming (ideally I'd be able -to provide a library that would refine std::partition() to other concepts -without fear of conflicting with other libraries doing the same - but -that is a digression). I consider the fact that partition isn't defined -to work for ForwardIterator a minor embarrassment. -

    - -

    [Mont Tremblant: Moved to Open, request motivation and use cases -by next meeting. Sean provided further rationale by post-meeting -mailing.]

    - - - - - - - -
    -

    532. Tuple comparison

    -

    Section: 20.5.2.5 [tuple.rel], TR1 6.1.3.5 [tr.tuple.rel] Status: Open - Submitter: David Abrahams Opened: 2005-11-29 Last modified: 2009-07-28

    -

    View all other issues in [tuple.rel].

    -

    View all issues with Open status.

    -

    Duplicate of: 348

    -

    Discussion:

    -

    -Where possible, tuple comparison operators <,<=,=>, and > ought to be -defined in terms of std::less rather than operator<, in order to -support comparison of tuples of pointers. -

    - -

    [ -2009-07-28 Reopened by Alisdair. No longer solved by concepts. -]

    - - - - -

    Proposed resolution:

    -

    -change 6.1.3.5/5 from: -

    - -

    - Returns: The result of a lexicographical comparison between t and - u. The result is defined as: (bool)(get<0>(t) < get<0>(u)) || - (!(bool)(get<0>(u) < get<0>(t)) && ttail < utail), where rtail for - some tuple r is a tuple containing all but the first element of - r. For any two zero-length tuples e and f, e < f returns false. -

    - -

    -to: -

    - -
    -

    - Returns: The result of a lexicographical comparison between t and - u. For any two zero-length tuples e and f, e < f returns false. - Otherwise, the result is defined as: cmp( get<0>(t), get<0>(u)) || - (!cmp(get<0>(u), get<0>(t)) && ttail < utail), where rtail for some - tuple r is a tuple containing all but the first element of r, and - cmp(x,y) is an unspecified function template defined as follows. -

    -

    - Where T is the type of x and U is the type of y: -

    - -

    - if T and U are pointer types and T is convertible to U, returns - less<U>()(x,y) -

    - -

    - otherwise, if T and U are pointer types, returns less<T>()(x,y) -

    - -

    - otherwise, returns (bool)(x < y) -

    -
    - -

    [ -Berlin: This issue is much bigger than just tuple (pair, containers, -algorithms). Dietmar will survey and work up proposed wording. -]

    - - - - -

    Rationale:

    -

    -Recommend NAD. This will be fixed with the next revision of concepts. -

    - -

    [ -San Francisco: -]

    - - -
    -Solved by -N2770. -
    - - - - -

    539. partial_sum and adjacent_difference should mention requirements

    -

    Section: 26.7.3 [partial.sum] Status: Open - Submitter: Marc Schoolderman Opened: 2006-02-06 Last modified: 2009-07-30

    -

    View all issues with Open status.

    +

    Section: 26.7.3 [partial.sum] Status: Ready + Submitter: Marc Schoolderman Opened: 2006-02-06 Last modified: 2009-10-24

    +

    View all issues with Ready status.

    Discussion:

    There are some problems in the definition of partial_sum and @@ -4020,6 +3204,16 @@ volunteered to correct the wording. ]

    +

    [ +2009-10 Santa Cruz: +]

    + + +
    +Move to Ready. +
    + +

    Proposed resolution:

    @@ -4159,10 +3353,10 @@ of binary_opthe binary operation.

    556. is Compare a BinaryPredicate?

    -

    Section: 25.5 [alg.sorting] Status: Open - Submitter: Martin Sebor Opened: 2006-02-05 Last modified: 2009-07-28

    +

    Section: 25.4 [alg.sorting] Status: Review + Submitter: Martin Sebor Opened: 2006-02-05 Last modified: 2009-10-25

    View all other issues in [alg.sorting].

    -

    View all issues with Open status.

    +

    View all issues with Review status.

    Discussion:

    In 25, p8 we allow BinaryPredicates to return a type that's convertible @@ -4192,14 +3386,44 @@ is here: argument is less than the second, and false otherwise...

    +

    [ +Portland: Jack to define "convertible to bool" such that short circuiting isn't +destroyed. +]

    + +

    [ 2009-07-28 Reopened by Alisdair. No longer solved by concepts. ]

    +

    [ +2009-10 Santa Cruz: +]

    -

    Proposed resolution:

    +
    +Move to Review once wording received. Stefanus to send proposed wording. +
    + +

    [ +2009-10 Santa Cruz: +]

    + + +
    +Move to Review once wording received. Stefanus to send proposed wording. +
    + +

    [ +2009-10-24 Stefanus supplied wording. +]

    + + +
    +Move to Review once wording received. Stefanus to send proposed wording. +Current proposed wording proposed here: +

    I think we could fix this by rewording 25.3, p2 to read somthing like:

    @@ -4213,12 +3437,25 @@ if the first argument of the call is less than the second, and algorithms assuming an ordering relation. It is assumed that comp will not apply any non-constant function through the dereferenced iterator.

    +
    + -

    [ -Portland: Jack to define "convertible to bool" such that short circuiting isn't -destroyed. -]

    + +

    Proposed resolution:

    +

    +Change 25.4 [alg.sorting] p2: +

    +
    +Compare is used as a function object. The return value of +the function call operator applied to an object of type Compare, when +converted to type bool, yields true if the first argument of the +call which returns true if the first argument +is less than the second, and false otherwise. Compare +comp is used throughout for algorithms assuming an ordering +relation. It is assumed that comp will not apply any +non-constant function through the dereferenced iterator. +

    Rationale:

    @@ -4237,529 +3474,10 @@ Solved by -
    -

    564. stringbuf seekpos underspecified

    -

    Section: 27.8.1.4 [stringbuf.virtuals] Status: Ready - Submitter: Martin Sebor Opened: 2006-02-23 Last modified: 2009-07-15

    -

    View all other issues in [stringbuf.virtuals].

    -

    View all issues with Ready status.

    -

    Discussion:

    -

    -The effects of the seekpos() member function of -basic_stringbuf simply say that the function positions -the input and/or output sequences but fail to spell out exactly -how. This is in contrast to the detail in which seekoff() -is described. -

    - -

    [ -2009-07 Frankfurt -]

    - - -
    -Move to Ready. -
    - - - -

    Proposed resolution:

    -

    - -Change 27.7.1.3, p13 to read: - -

    -
    -

    --13- Effects: Equivalent to seekoff(off_type(sp), ios_base::beg, -which). Alters the stream position within the controlled sequences, -if possible, to correspond to the stream position stored in sp -(as described below). -

    -
      -
    • If (which & ios_base::in) != 0, positions the input sequence.
      • -
    • If (which & ios_base::out) != 0, positions the output sequence.
      • -
    • If sp is an invalid stream position, or if the function -positions neither sequence, the positioning operation fails. If sp -has not been obtained by a previous successful call to one of the positioning -functions (seekoff, seekpos, tellg, tellp) -the effect is undefined.
      • -
    -
    - - -

    [ -Kona (2007): A pos_type is a position in a stream by -definition, so there is no ambiguity as to what it means. Proposed -Disposition: NAD -]

    - - -

    [ -Post-Kona Martin adds: -I'm afraid I disagree -with the Kona '07 rationale for marking it NAD. The only text -that describes precisely what it means to position the input -or output sequence is in seekoff(). The seekpos() Effects -clause is inadequate in comparison and the proposed resolution -plugs the hole by specifying seekpos() in terms of seekoff(). -]

    - - - - - -
    -

    565. xsputn inefficient

    -

    Section: 27.6.2.4.5 [streambuf.virt.put] Status: Ready - Submitter: Martin Sebor Opened: 2006-02-23 Last modified: 2009-07-15

    -

    View all issues with Ready status.

    -

    Discussion:

    -

    - -streambuf::xsputn() is specified to have the effect of -"writing up to n characters to the output sequence as if by -repeated calls to sputc(c)." - -

    -

    - -Since sputc() is required to call overflow() when -(pptr() == epptr()) is true, strictly speaking -xsputn() should do the same. However, doing so would be -suboptimal in some interesting cases, such as in unbuffered mode or -when the buffer is basic_stringbuf. - -

    -

    - -Assuming calling overflow() is not really intended to be -required and the wording is simply meant to describe the general -effect of appending to the end of the sequence it would be worthwhile -to mention in xsputn() that the function is not actually -required to cause a call to overflow(). - -

    - -

    [ -2009-07 Frankfurt -]

    - - -
    -Move to Ready. -
    - - - -

    Proposed resolution:

    -

    - -Add the following sentence to the xsputn() Effects clause in -27.5.2.4.5, p1 (N1804): - -

    -
    -

    --1- Effects: Writes up to n characters to the output -sequence as if by repeated calls to sputc(c). The characters -written are obtained from successive elements of the array whose first element -is designated by s. Writing stops when either n -characters have been written or a call to sputc(c) would return -traits::eof(). It is uspecified whether the function calls -overflow() when (pptr() == epptr()) becomes true or whether -it achieves the same effects by other means. -

    -
    -

    - -In addition, I suggest to add a footnote to this function with the -same text as Footnote 292 to make it extra clear that derived classes -are permitted to override xsputn() for efficiency. - -

    - - -

    [ -Kona (2007): We want to permit a streambuf that streams output directly -to a device without making calls to sputc or overflow. We believe that -has always been the intention of the committee. We believe that the -proposed wording doesn't accomplish that. Proposed Disposition: Open -]

    - - - - - -
    -

    580. unused allocator members

    -

    Section: 23.2.1 [container.requirements.general] Status: Open - Submitter: Martin Sebor Opened: 2006-06-14 Last modified: 2009-07-15

    -

    View other active issues in [container.requirements.general].

    -

    View all other issues in [container.requirements.general].

    -

    View all issues with Open status.

    -

    Duplicate of: 479

    -

    Discussion:

    -

    - -C++ Standard Library templates that take an allocator as an argument -are required to call the allocate() and -deallocate() members of the allocator object to obtain -storage. However, they do not appear to be required to call any other -allocator members such as construct(), -destroy(), address(), and -max_size(). This makes these allocator members less than -useful in portable programs. - -

    -

    - -It's unclear to me whether the absence of the requirement to use these -allocator members is an unintentional omission or a deliberate -choice. However, since the functions exist in the standard allocator -and since they are required to be provided by any user-defined -allocator I believe the standard ought to be clarified to explictly -specify whether programs should or should not be able to rely on -standard containers calling the functions. - -

    -

    - -I propose that all containers be required to make use of these -functions. - -

    -

    [ -Batavia: We support this resolution. Martin to provide wording. -]

    - -

    [ -pre-Oxford: Martin provided wording. -]

    - - -

    [ -2009-04-28 Pablo adds: -]

    - - -
    -N2554 -(scoped allocators), -N2768 -(allocator concepts), and -N2810 -(allocator defects), address all of these points EXCEPT max_size(). -So, I would add a note to that affect and re-class the defect as belonging -to section 23.2.1 [container.requirements.general]. -
    - -

    [ -2009-07 Frankfurt -]

    - - -
    -The comment in the description of this issue that this "would be" -rendered editorial by the adoption of N2257 is confusing. It appears -that N2257 was never adopted. -
    - - - -

    Proposed resolution:

    -

    - -Specifically, I propose to change 23.2 [container.requirements], -p9 as follows: - -

    -
    -

    --9- Copy constructors for all container types defined in this clause -that are parametrized on Allocator copy -anthe allocator argument from their respective -first parameters. - -All other constructors for these container types take an -const Allocator& argument (20.1.6), an -allocator whose value_type is the same as the container's -value_type. - -A copy of this argument isshall be used for any -memory allocation and deallocation performed, -by these constructors and by all member functions, during -the lifetime of each container object. Allocation shall be -performed "as if" by calling the allocate() member -function on a copy of the allocator object of the appropriate type -New Footnote), and deallocation "as if" by calling -deallocate() on a copy of the same allocator object of -the corresponding type. - -A copy of this argument shall also be used to construct and -destroy objects whose lifetime is managed by the container, including -but not limited to those of the container's value_type, -and to obtain their address. All objects residing in storage -allocated by a container's allocator shall be constructed "as if" by -calling the construct() member function on a copy of the -allocator object of the appropriate type. The same objects shall be -destroyed "as if" by calling destroy() on a copy of the -same allocator object of the same type. The address of such objects -shall be obtained "as if" by calling the address() member -function on a copy of the allocator object of the appropriate -type. - -Finally, a copy of this argument shall be used by its container -object to determine the maximum number of objects of the container's -value_type the container may store at the same time. The -container member function max_size() obtains this number -from the value returned by a call to -get_allocator().max_size(). - -In all container types defined in this clause that are -parametrized on Allocator, the member -get_allocator() returns a copy of the -Allocator object used to construct the -container.258) -

    -

    -New Footnote: This type may be different from Allocator: -it may be derived from Allocator via -Allocator::rebind<U>::other for the appropriate -type U. -

    -
    -

    - -The proposed wording seems cumbersome but I couldn't think of a better -way to describe the requirement that containers use their -Allocator to manage only objects (regardless of their -type) that persist over their lifetimes and not, for example, -temporaries created on the stack. That is, containers shouldn't be -required to call Allocator::construct(Allocator::allocate(1), -elem) just to construct a temporary copy of an element, or -Allocator::destroy(Allocator::address(temp), 1) to -destroy temporaries. - -

    - - -

    [ -Howard: This same paragraph will need some work to accommodate 431. -]

    - - -

    [ -post Oxford: This would be rendered NAD Editorial by acceptance of -N2257. -]

    - - - - - -
    -

    588. requirements on zero sized tr1::arrays and other details

    -

    Section: 23.3.1 [array] Status: Tentatively NAD - Submitter: Gennaro Prota Opened: 2006-07-18 Last modified: 2009-07-15

    -

    View other active issues in [array].

    -

    View all other issues in [array].

    -

    View all issues with Tentatively NAD status.

    -

    Discussion:

    -

    -The wording used for section 23.2.1 [lib.array] seems to be subtly -ambiguous about zero sized arrays (N==0). Specifically: -

    -

    -* "An instance of array<T, N> stores N elements of type T, so that -[...]" -

    -

    -Does this imply that a zero sized array object stores 0 elements, i.e. -that it cannot store any element of type T? The next point clarifies -the rationale behind this question, basically how to implement begin() -and end(): -

    -

    -* 23.2.1.5 [lib.array.zero], p2: "In the case that N == 0, begin() == -end() == unique value." -

    -

    -What does "unique" mean in this context? Let's consider the following -possible implementations, all relying on a partial specialization: -

    -
    a)
-    template< typename T >
-    class array< T, 0 > {
-    
-        ....
-
-        iterator begin()
-        { return iterator( reinterpret_cast< T * >( this ) ); }
-        ....
-
-    };
-
    -

    -This has been used in boost, probably intending that the return value -had to be unique to the specific array object and that array couldn't -store any T. Note that, besides relying on a reinterpret_cast, has -(more than potential) alignment problems. -

    -
    b)
-    template< typename T >
-    class array< T, 0 > {
-    
-        T t;
-
-        iterator begin()
-        { return iterator( &t ); }
-        ....
-
-    };
-
    -

    -This provides a value which is unique to the object and to the type of -the array, but requires storing a T. Also, it would allow the user to -mistakenly provide an initializer list with one element. -

    -

    -A slight variant could be returning *the* null pointer of type T -

    -
        return static_cast<T*>(0);
-
    -

    -In this case the value would be unique to the type array<T, 0> but not -to the objects (all objects of type array<T, 0> with the same value -for T would yield the same pointer value). -

    -

    -Furthermore this is inconsistent with what the standard requires from -allocation functions (see library issue 9). -

    -

    -c) same as above but with t being a static data member; again, the -value would be unique to the type, not to the object. -

    -

    -d) to avoid storing a T *directly* while disallowing the possibility -to use a one-element initializer list a non-aggregate nested class -could be defined -

    -
        struct holder { holder() {} T t; } h;
-
    -

    -and then begin be defined as -

    -
     iterator begin() { return &h.t; }
-
    -

    -But then, it's arguable whether the array stores a T or not. -Indirectly it does. -

    -

    ------------------------------------------------------ -

    -

    -Now, on different issues: -

    -

    -* what's the effect of calling assign(T&) on a zero-sized array? There -seems to be only mention of front() and back(), in 23.2.1 [lib.array] -p4 (I would also suggest to move that bullet to section 23.2.1.5 -[lib.array.zero], for locality of reference) -

    -

    -* (minor) the opening paragraph of 23.2.1 [lib.array] wording is a bit -inconsistent with that of other sequences: that's not a problem in -itself, but compare it for instance with "A vector is a kind of -sequence that supports random access iterators"; though the intent is -obvious one might argue that the wording used for arrays doesn't tell -what an array is, and relies on the reader to infer that it is what -the <array> header defines. -

    -

    -* it would be desiderable to have a static const data member of type -std::size_t, with value N, for usage as integral constant expression -

    -

    -* section 23.1 [lib.container.requirements] seem not to consider -fixed-size containers at all, as it says: "[containers] control -allocation and deallocation of these objects [the contained objects] -through constructors, destructors, *insert and erase* operations" -

    -

    -* max_size() isn't specified: the result is obvious but, technically, -it relies on table 80: "size() of the largest possible container" -which, again, doesn't seem to consider fixed size containers -

    - -

    [ -2009-05-29 Daniel adds: -]

    - - -
    -
      -
    1. -

      -star bullet 1 ("what's the effect of calling assign(T&) on a -zero-sized array?[..]"); -

      -
      -assign has been renamed to fill and the semantic of fill is now -defined in terms of -the free algorithm fill_n, which is well-defined for this situation. -
      -
      2. -
    2. -

      -star bullet 3 ("it would be desiderable to have a static const data -member..."): -

      -
      -It seems that tuple_size<array<T, N> >::value as of 23.3.1.7 [array.tuple] does -provide this functionality now. -
      -
      3. -
    -
    - -

    [ -2009-07 Frankfurt -]

    - - -
    -

    -Alisdair to address by the next meeting, or declare NAD. -

    -

    -Moved to Tentatively NAD. -

    -
    - - - -

    Proposed resolution:

    -

    -

    - - -

    [ -Kona (2007): requirements on zero sized tr1::arrays and other details -Issue 617: std::array is a sequence that doesn't satisfy the sequence -requirements? Alisdair will prepare a paper. Proposed Disposition: Open -]

    - - - - -

    594. Disadvantages of defining Swappable in terms of CopyConstructible and Assignable

    -

    Section: X [utility.arg.requirements] Status: Open - Submitter: Niels Dekker Opened: 2006-11-02 Last modified: 2009-07-26

    +

    Section: 20.2.1 [utility.arg.requirements] Status: Open + Submitter: Niels Dekker Opened: 2006-11-02 Last modified: 2009-11-08

    View other active issues in [utility.arg.requirements].

    View all other issues in [utility.arg.requirements].

    View all issues with Open status.

    @@ -4792,13 +3510,17 @@ swap(t,u) is valid and has the semantics described in Table 33. +

    I can think of three disadvantages of this definition: +

    1. +

      If a client's type T satisfies the first condition (T is both CopyConstructible and Assignable), the client cannot stop T from satisfying the Swappable requirement without stopping T from satisfying the first condition. +

      A client might want to stop T from satisfying the Swappable requirement, because swapping by means of copy construction and @@ -4815,8 +3537,10 @@ stopping T from satisfying the Swappable requirement.

    2. +

      A client's type T that does not satisfy the first condition can not be made Swappable by providing a specialization of std::swap for T. +

      While I'm aware about the fact that people have mixed feelings about providing a specialization of std::swap, it is well-defined to do so. @@ -4827,11 +3551,13 @@ effect as satisfying the Swappable requirement.

    3. +

      For a client's type T that satisfies both conditions of the Swappable requirement, it is not specified which of the two conditions prevails. After reading section 20.1.4 [lib.swappable], one might wonder whether objects of T will be swapped by doing copy construction and assignments, or by calling the swap function of T. +

      I'm aware that the intention of the Draft is to prefer calling the swap function of T over doing copy construction and assignments. Still @@ -4878,6 +3604,15 @@ Recommend NAD. Solved by Moved to Open. Waiting for non-concepts draft. +

      [ +2009-11-08 Howard adds: +]

      + + +
      +This issue is very closely related to 742. +
      +

      Proposed resolution:

      @@ -4909,132 +3644,13 @@ within the namespace std, and has the semantics described in Table 33. -

      -

      617. std::array is a sequence that doesn't satisfy the sequence requirements?

      -

      Section: 23.3.1 [array] Status: Tentatively NAD - Submitter: Bo Persson Opened: 2006-12-30 Last modified: 2009-07-16

      -

      View other active issues in [array].

      -

      View all other issues in [array].

      -

      View all issues with Tentatively NAD status.

      -

      Discussion:

      -

      -The <array> header is given under 23.3 [sequences]. -23.3.1 [array]/paragraph 3 says: -

      -

      -"Unless otherwise specified, all array operations are as described in -23.2 [container.requirements]". -

      -

      -However, array isn't mentioned at all in section 23.2 [container.requirements]. -In particular, Table 82 "Sequence requirements" lists several operations (insert, erase, clear) -that std::array does not have in 23.3.1 [array]. -

      -

      -Also, Table 83 "Optional sequence operations" lists several operations that -std::array does have, but array isn't mentioned. -

      - -

      [ -2009-07 Frankfurt -]

      - - -
      -

      -The real issue seems to be different than what is described here. -Non-normative text says that std::array is a sequence container, but -there is disagreement about what that really means. There are two -possible interpretations: -

      -
        -
      1. -a sequence container is one that satisfies all sequence container requirements -
        2. -
      2. -a sequence container is one that satisfies some of the sequence -container requirements. Any operation that the container supports is -specified by one or more sequence container requirements, unless that -operation is specifically singled out and defined alongside the -description of the container itself. -
        3. -
      -

      -Move to Tentatively NAD. -

      -
      - -

      [ -2009-07-15 Loďc Joly adds: -]

      - - -
      -

      -The section 23.2.3 [sequence.reqmts]/1 states that array is a sequence. 23.2.3 [sequence.reqmts]/3 -introduces table 83, named Sequence container requirements. This seems -to me to be defining the requirements for all sequences. However, array -does not follow all of this requirements (this can be read in the array -specific section, for the standard is currently inconsistent). -

      - -

      -Proposed resolution 1 (minimal change): -

      -
      -

      -Say that array is a container, that in addition follows only some of the -sequence requirements, as described in the array section: -

      - -
      -The library provides five three basic kinds of sequence containers: array, -vector, -forward_list, list, and deque. In addition, array -and forward_list follows some of the requirements -of sequences, as described in their respective sections. -
      - -
      - -

      -Proposed resolution 2 (most descriptive description, no full wording provided): -

      -
      -Introduce the notion of a Fixed Size Sequence, with it requirement table -that would be a subset of the current Sequence container. array would be -the only Fixed Size Sequence (but dynarray is in the queue for TR2). -Sequence requirements would now be requirements in addition to Fixed -Size Sequence requirements (it is currently in addition to container). -
      -
      - -

      [ -2009-07 Frankfurt: -]

      - - -
      -Move to NAD Editorial -
      - - - -

      Proposed resolution:

      -

      -

      - - - - -

      625. mixed up Effects and Returns clauses

      -

      Section: 17 [library] Status: Tentatively NAD - Submitter: Martin Sebor Opened: 2007-01-20 Last modified: 2009-07-15

      +

      Section: 17 [library] Status: Open + Submitter: Martin Sebor Opened: 2007-01-20 Last modified: 2009-10-20

      View other active issues in [library].

      View all other issues in [library].

      -

      View all issues with Tentatively NAD status.

      +

      View all issues with Open status.

      Duplicate of: 895

      Discussion:

      @@ -5167,187 +3783,20 @@ is confusing, especially now that requires is a new keyword. Move to Tentatively NAD. - - -

      Proposed resolution:

      -

      -

      - - - - - -
      -

      630. arrays of valarray

      -

      Section: 26.6.2.1 [valarray.cons] Status: Ready - Submitter: Martin Sebor Opened: 2007-01-28 Last modified: 2009-07-15

      -

      View all other issues in [valarray.cons].

      -

      View all issues with Ready status.

      -

      Discussion:

      -

      - -Section 26.2 [numeric.requirements], p1 suggests that a -valarray specialization on a type T that -satisfies the requirements enumerated in the paragraph is itself a -valid type on which valarray may be instantiated -(Footnote 269 makes this clear). I.e., -valarray<valarray<T> > is valid as long as -T is valid. However, since implementations of -valarray are permitted to initialize storage allocated by -the class by invoking the default ctor of T followed by -the copy assignment operator, such implementations of -valarray wouldn't work with (perhaps user-defined) -specializations of valarray whose assignment operator had -undefined behavior when the size of its argument didn't match the size -of *this. By "wouldn't work" I mean that it would -be impossible to resize such an array of arrays by calling the -resize() member function on it if the function used the -copy assignment operator after constructing all elements using the -default ctor (e.g., by invoking new value_type[N]) to -obtain default-initialized storage) as it's permitted to do. - -

      -

      - -Stated more generally, the problem is that -valarray<valarray<T> >::resize(size_t) isn't -required or guaranteed to have well-defined semantics for every type -T that satisfies all requirements in -26.2 [numeric.requirements]. - -

      -

      - -I believe this problem was introduced by the adoption of the -resolution outlined in N0857, -Assignment of valarrays, from 1996. The copy assignment -operator of the original numerical array classes proposed in N0280, -as well as the one proposed in N0308 -(both from 1993), had well-defined semantics for arrays of unequal -size (the latter explicitly only when *this was empty; -assignment of non empty arrays of unequal size was a runtime error). - -

      -

      - -The justification for the change given in N0857 was the "loss of -performance [deemed] only significant for very simple operations on -small arrays or for architectures with very few registers." - -

      -

      - -Since tiny arrays on a limited subset of hardware architectures are -likely to be an exceedingly rare case (despite the continued -popularity of x86) I propose to revert the resolution and make the -behavior of all valarray assignment operators -well-defined even for non-conformal arrays (i.e., arrays of unequal -size). I have implemented this change and measured no significant -degradation in performance in the common case (non-empty arrays of -equal size). I have measured a 50% (and in some cases even greater) -speedup in the case of assignments to empty arrays versus calling -resize() first followed by an invocation of the copy -assignment operator. - -

      -

      [ -Bellevue: +2009 Santa Cruz: ]

      -If no proposed wording by June meeting, this issue should be closed NAD. -
      - -

      [ -2009-07 Frankfurt -]

      - - -
      -

      -Move resolution 1 to Ready. -

      -

      -Howard: second resolution has been commented out (made invisible). -Can be brought back on demand. -

      +Move to Open. Martin will work on proposed wording.

      Proposed resolution:

      -

      - -Change 26.6.2.2 [valarray.assign], p1 as follows: - -

      -
      -

      - - -valarray<T>& operator=(const valarray<T>& x); - - -

      -

      - --1- Each element of the *this array is assigned the value -of the corresponding element of the argument array. The -resulting behavior is undefined if When the length of -the argument array is not equal to the length of the *this -array. resizes *this to make the two -arrays the same length, as if by calling -resize(x.size()), before performing the assignment. - -

      -
      -

      - -And add a new paragraph just below paragraph 1 with the following -text: - -

      -
      -

      - --2- Postcondition: size() == x.size(). - -

      -
      -

      - -Also add the following paragraph to 26.6.2.2 [valarray.assign], immediately after p4: - -

      -
      -

      - --?- When the length, N of the array referred -to by the argument is not equal to the length of *this, -the operator resizes *this to make the two arrays the -same length, as if by calling resize(N), before -performing the assignment. - -

      -
      - -

      [ -pre-Sophia Antipolis, Martin adds the following compromise wording, but -prefers the original proposed resolution: -]

      - - - - - - -

      [ -Kona (2007): Gaby to propose wording for an alternative resolution in -which you can assign to a valarray of size 0, but not to any other -valarray whose size is unequal to the right hand side of the assignment. -]

      +

      +

      @@ -5355,11 +3804,11 @@ which you can assign to a valarray of size 0, but not to any other

      631. conflicting requirements for BinaryPredicate

      -

      Section: 25 [algorithms] Status: Open - Submitter: James Kanze Opened: 2007-01-31 Last modified: 2009-07-28

      +

      Section: 25 [algorithms] Status: Review + Submitter: James Kanze Opened: 2007-01-31 Last modified: 2009-10-24

      View other active issues in [algorithms].

      View all other issues in [algorithms].

      -

      View all issues with Open status.

      +

      View all issues with Review status.

      Discussion:

      The general requirements for BinaryPredicate (in 25 [algorithms]/8) contradict the implied specific requirements for @@ -5378,7 +3827,7 @@ part of the signature, it should work correctly in the context of if

      -In the description of upper_bound (25.5.3.2 [upper.bound]/2), however, the use is described as +In the description of upper_bound (25.4.3.2 [upper.bound]/2), however, the use is described as "!comp(value, e)", where e is an element of the sequence (a result of dereferencing *first). @@ -5403,6 +3852,19 @@ and upper_bound to work withoutt these changes. ]

      +

      [ +2009-10 Santa Cruz: +]

      + + +
      +Move to Review. The small problem with the "iterator type" +will be fixed. The cited functions (lower_bound, uppwer_bound, +equal_range) don't actually use BinaryPredicate , and where it is used, +it is consistent with [algorithm]/8, so the main complaint of the issue +is moot. +
      +

      Proposed resolution:

      @@ -5450,7 +3912,7 @@ post San Francisco:
      Solved by -N2759. +N2759.
      @@ -5458,533 +3920,13 @@ Solved by -
      -

      635. domain of allocator::address

      -

      Section: X [allocator.requirements] Status: Open - Submitter: Howard Hinnant Opened: 2007-02-08 Last modified: 2009-07-28

      -

      View other active issues in [allocator.requirements].

      -

      View all other issues in [allocator.requirements].

      -

      View all issues with Open status.

      -

      Discussion:

      -

      -The table of allocator requirements in X [allocator.requirements] describes -allocator::address as: -

      -
      a.address(r)
-a.address(s)
-
      -

      -where r and s are described as: -

      -

      -a value of type X::reference obtained by the expression *p. -

      - -

      -and p is -

      - -

      -a value of type X::pointer, obtained by calling a1.allocate, -where a1 == a -

      - -

      -This all implies that to get the address of some value of type T that -value must have been allocated by this allocator or a copy of it. -

      - -

      -However sometimes container code needs to compare the address of an external value of -type T with an internal value. For example list::remove(const T& t) -may want to compare the address of the external value t with that of a value -stored within the list. Similarly vector or deque insert may -want to make similar comparisons (to check for self-referencing calls). -

      - -

      -Mandating that allocator::address can only be called for values which the -allocator allocated seems overly restrictive. -

      - -

      [ -post San Francisco: -]

      - - -
      -Pablo recommends NAD Editorial, solved by -N2768. -
      - -

      [ -2009-04-28 Pablo adds: -]

      - - -
      -Tentatively-ready NAD Editorial as fixed by -N2768. -
      - -

      [ -2009-07 Frankfurt -]

      - - -
      -Fixed by N2768. -
      - -

      [ -2009-07-28 Reopened by Alisdair. No longer solved by concepts. -]

      - - - - -

      Proposed resolution:

      -

      -Change X [allocator.requirements]: -

      - -
      -

      -r : a value of type X::reference obtained by the expression *p. -

      -

      -s : a value of type X::const_reference obtained by the -expression *q or by conversion from a value r. -

      -
      - -

      [ -post Oxford: This would be rendered NAD Editorial by acceptance of -N2257. -]

      - - -

      [ -Kona (2007): This issue is section 8 of N2387. There was some discussion of it but -no resolution to this issue was recorded. Moved to Open. -]

      - - - - - - - -
      -

      659. istreambuf_iterator should have an operator->()

      -

      Section: 24.6.3 [istreambuf.iterator] Status: Ready - Submitter: Niels Dekker Opened: 2007-03-25 Last modified: 2009-07-15

      -

      View all other issues in [istreambuf.iterator].

      -

      View all issues with Ready status.

      -

      Discussion:

      -

      -Greg Herlihy has clearly demonstrated that a user defined input -iterator should have an operator->(), even if its -value type is a built-in type (comp.std.c++, "Re: Should any iterator -have an operator->() in C++0x?", March 2007). And as Howard -Hinnant remarked in the same thread that the input iterator -istreambuf_iterator doesn't have one, this must be a -defect! -

      -

      -Based on Greg's example, the following code demonstrates the issue: -

       #include <iostream> 
- #include <fstream>
- #include <streambuf> 
-
- typedef char C;
- int main ()
- {
-   std::ifstream s("filename", std::ios::in);
-   std::istreambuf_iterator<char> i(s);
-
-   (*i).~C();  // This is well-formed...
-   i->~C();  // ... so this should be supported!
- }
-
      - -

      -Of course, operator-> is also needed when the value_type of -istreambuf_iterator is a class. -

      -

      -The operator-> could be implemented in various ways. For instance, -by storing the current value inside the iterator, and returning its -address. Or by returning a proxy, like operator_arrow_proxy, from -http://www.boost.org/boost/iterator/iterator_facade.hpp -

      -

      -I hope that the resolution of this issue will contribute to getting a -clear and consistent definition of iterator concepts. -

      - -

      [ -Kona (2007): The proposed resolution is inconsistent because the return -type of istreambuf_iterator::operator->() is specified to be pointer, -but the proposed text also states that "operator-> may return a proxy." -]

      - - -

      [ -Niels Dekker (mailed to Howard Hinnant): -]

      - -
      -

      -The proposed resolution does -not seem inconsistent to me. istreambuf_iterator::operator->() should -have istreambuf_iterator::pointer as return type, and this return type -may in fact be a proxy. -

      -

      -AFAIK, the resolution of 445 ("iterator_traits::reference -unspecified for some iterator categories") implies that for any iterator -class Iter, the return type of operator->() is Iter::pointer, by -definition. I don't think Iter::pointer needs to be a raw pointer. -

      -

      -Still I wouldn't mind if the text "operator-> may return a proxy" would -be removed from the resolution. I think it's up to the library -implementation, how to implement istreambuf_iterator::operator->(). As -longs as it behaves as expected: i->m should have the same effect as -(*i).m. Even for an explicit destructor call, i->~C(). The main issue -is just: istreambuf_iterator should have an operator->()! -

      -
      - -

      [ -2009-04-30 Alisdair adds: -]

      - - -
      -Note that operator-> is now a requirement in the InputIterator concept, so -this issue cannot be ignored or existing valid programs will break when -compiled with an 0x library. -
      - -

      [ -2009-05-29 Alisdair adds: -]

      - - -
      -

      -I agree with the observation that in principle the type 'pointer' may be a -proxy, and the words highlighting this are redundant. -

      -

      -However, in the current draught pointer is required to be exactly 'charT *' -by the derivation from std::iterator. At a minimum, the 4th parameter of -this base class template should become unspecified. That permits the -introduction of a proxy as a nested class in some further undocumented (not -even exposition-only) base. -

      -

      -It also permits the istream_iterator approach where the cached value is -stored in the iterator itself, and the iterator serves as its own proxy for -post-increment operator++ - removing the need for the existing -exposition-only nested class proxy. -

      -

      -Note that the current proxy class also has exactly the right properties to -serve as the pointer proxy too. This is likely to be a common case where an -InputIterator does not hold internal state but delegates to another class. -

      -

      -Proposed Resolution: -

      -

      -In addition to the current proposal: -

      -

      -24.6.3 [istreambuf.iterator] -

      -
      template<class charT, class traits = char_traits<charT> >
-class istreambuf_iterator
-  : public iterator<input_iterator_tag, charT,
-                    typename traits::off_type, charT* unspecified, charT> {
-
      -
      - -

      [ -2009-07 Frankfurt -]

      - - -
      -

      -Move the additional part into the proposed resolution, and wrap the -descriptive text in a Note. -

      -

      [Howard: done.]

      - -

      -Move to Ready. -

      -
      - - - -

      Proposed resolution:

      -

      -Add to the synopsis in 24.6.3 [istreambuf.iterator]: -

      - -
      charT operator*() const;
-pointer operator->() const;
-istreambuf_iterator<charT,traits>& operator++();
-
      - -

      -24.6.3 [istreambuf.iterator] -

      - -
      template<class charT, class traits = char_traits<charT> >
-class istreambuf_iterator
-  : public iterator<input_iterator_tag, charT,
-                    typename traits::off_type, charT* unspecified, charT> {
-
      - -

      -Change 24.6.3 [istreambuf.iterator], p1: -

      - -

      -The class template istreambuf_iterator reads successive -characters from the streambuf for which it was constructed. -operator* provides access to the current input character, if -any. [Note: operator-> may return a proxy. — -end note] Each time -operator++ is evaluated, the iterator advances to the next -input character. If the end of stream is reached -(streambuf_type::sgetc() returns traits::eof()), the -iterator becomes equal to the end of stream iterator value. The default -constructor istreambuf_iterator() and the constructor -istreambuf_iterator(0) both construct an end of stream iterator -object suitable for use as an end-of-range. -

      - - - - - - - -
      -

      668. money_get's empty minus sign

      -

      Section: 22.4.6.1.2 [locale.money.get.virtuals] Status: Review - Submitter: Thomas Plum Opened: 2007-04-16 Last modified: 2009-07-20

      -

      View other active issues in [locale.money.get.virtuals].

      -

      View all other issues in [locale.money.get.virtuals].

      -

      View all issues with Review status.

      -

      Discussion:

      -

      -22.4.6.1.2 [locale.money.get.virtuals], para 3 says: -

      - -

      -If pos or neg is empty, the sign component is -optional, and if no sign is detected, the result is given the sign -that corresponds to the source of the empty string. -

      - -

      -The following objection has been raised: -

      - -

      -A negative_sign of "" means "there is no -way to write a negative sign" not "any null sequence is a negative -sign, so it's always there when you look for it". -

      - -

      -[Plum ref _222612Y32] -

      - -

      [ -Kona (2007): Bill to provide proposed wording and interpretation of existing wording. -]

      - - -

      -Related to 669. -

      - -

      [ -2009-05-17 Howard adds: -]

      - - -
      -

      -I disagree that a negative_sign of "" means "there is no -way to -write a negative sign". The meaning requires the sentences of -22.4.6.1.2 [locale.money.get.virtuals] p3 following that quoted above -to be -taken into account: -

      - -
      --3- ... If pos or neg is empty, the sign component is -optional, and if no sign is detected, the result is given the sign that -corresponds to the source of the empty string. Otherwise, the character -in the indicated position must match the first character of pos -or neg, and the result is given the corresponding sign. If the -first character of pos is equal to the first character of -neg, or if both strings are empty, the result is given a -positive sign. -
      - -

      -So a negative_sign of "" means "there is no way to write a -negative sign" only when positive_sign is also "". However -when negative_sign is "" and postive_sign.size() > -0, then one writes a negative value by not writing the -postive_sign in the position indicated by -money_base::sign. -For example: -

      - -
      pattern = {symbol, sign, value, none}
-positive_sign = "+"
-negative_sign = ""
-$123   // a negative value, using optional sign
-$+123  // a positive value
-$-123  // a parse error
-
      - -

      -And: -

      - -
      pattern = {symbol, sign, value, none}
-positive_sign = ""
-negative_sign = ""
-$123   // a positive value, no sign possible
-$+123  // a parse error
-$-123  // a parse error
-
      - - -

      -And (regarding 669): -

      - -
      pattern = {symbol, sign, value, none}
-positive_sign = "-"
-negative_sign = "-"
-$123   // a parse error, sign is mandatory
-$+123  // a parse error
-$-123  // a positive value
-
      - - -

      -The text seems both unambiguous and clear to me. I recommend NAD for -both this issue and 669. However I would have no -objection to adding examples such as those above. -

      -
      - -

      [ -Batavia (2009-05): -]

      - -
      -

      -This discussion applies equally to issue 669 (q.v.). -Howard has added examples above, -and recommends either NAD or a resolution that adds his (or similar) examples -to the Working Paper. -

      -

      -Alan would like to rewrite paragraph 3. -

      -

      -We recommend moving to NAD. -Anyone who feels strongly about adding the examples -is invited to submit corresponding wording. -We further recommend issue 669 be handled identically. -

      -
      - -

      [ -2009-07-14 Alan reopens with improved wording. -]

      - - -

      [ -2009-07 Frankfurt -]

      - - -
      -No consensus for closing as NAD. Leave in Review. -
      - - - -

      Proposed resolution:

      -

      -Change 22.4.6.1.2 [locale.money.get.virtuals] p3: -

      - -
      --3- If the first character (if any) in the string pos returned by -mp.positive_sign() or the string neg returned by -mp.negative_sign() is recognized in the position indicated by -sign in the format pattern, it is consumed and any remaining characters -in the string are required after all the other format components. -[Example: If showbase is off�, then for a neg -value of "()" and a currency symbol of "L", in "(100 L)" the "L" is -consumed; but if neg is "-", the "L" in "-100 L" is not -consumed. -- end example] If pos or neg is -empty, the sign component is optional, and if no sign is detected, the -result is given the sign that corresponds to the source of the empty -string. Otherwise, the character in the indicated position must match -the first character of pos or neg, and the result is -given the corresponding sign. If the first character of pos is -equal to the first character of neg, or if both strings are -empty, the result is given a positive sign. - -The sign pattern strings pos and neg are returned by -mp.positive_sign() and mp.negative_sign() respectively. A sign pattern -is matched if its first character is recognized in s in the position -indicated by sign in the format pattern, or if the pattern is empty and -there is no sign recognized in s. A match is required to occur. If both -patterns are matched, the result is given a positive sign, otherwise the -result is given the sign corresponding to the matched pattern. -If the pattern contains more than one character, the characters after the first -must be matched in s after all other format components. -If any sign -characters are matched, s is consumed up to and including those characters. -[Example: If showbase is off, then for a neg -value of "()" and a currency symbol of "L", in -"(100 L)" the entire string is consumed; but for a neg -value of "-", in "-100 L", the string is consumed -through the second "0" (the space and "L" are not consumed). — end -example] -
      - - - - -

      671. precision of hexfloat

      -

      Section: 22.4.2.2.2 [facet.num.put.virtuals] Status: Review - Submitter: John Salmon Opened: 2007-04-20 Last modified: 2009-07-26

      +

      Section: 22.4.2.2.2 [facet.num.put.virtuals] Status: Ready + Submitter: John Salmon Opened: 2007-04-20 Last modified: 2009-10-21

      View other active issues in [facet.num.put.virtuals].

      View all other issues in [facet.num.put.virtuals].

      -

      View all issues with Review status.

      +

      View all issues with Ready status.

      Discussion:

      I am trying to understand how TR1 supports hex float (%a) output. @@ -6066,6 +4008,15 @@ Daniel and Robert have direction to write up wording for the "always %a" solutio +

      [ +2009-10 Santa Cruz: +]

      + + +
      +Move to Ready. +
      +

      Proposed resolution:

      @@ -6093,10 +4044,10 @@ Kona (2007): Robert volunteers to propose wording.

      676. Moving the unordered containers

      -

      Section: 23.5 [unord] Status: Open - Submitter: Howard Hinnant Opened: 2007-05-05 Last modified: 2009-07-28

      +

      Section: 23.5 [unord] Status: Review + Submitter: Howard Hinnant Opened: 2007-05-05 Last modified: 2009-10-29

      View all other issues in [unord].

      -

      View all issues with Open status.

      +

      View all issues with Review status.

      Discussion:

      Move semantics are missing from the unordered containers. The proposed @@ -6118,65 +4069,29 @@ on getting the unordered containers "moved". ]

      +

      [ +2009-10-17 Removed rvalue-swaps from wording. +]

      + + +

      [ +2009-10 Santa Cruz: +]

      + + +
      +Move to Review. Alisdair will review proposed wording. +
      + +

      [ +2009-10-29 Daniel updates wording. +]

      + +

      Proposed resolution:

      -

      -Add to 23.5 [unord]: -

      - -
      template <class Key, class T, class Hash, class Pred, class Alloc> 
-  void swap(unordered_map<Key, T, Hash, Pred, Alloc>& x, 
-            unordered_map<Key, T, Hash, Pred, Alloc>& y); 
-
-template <class Key, class T, class Hash, class Pred, class Alloc> 
-  void swap(unordered_map<Key, T, Hash, Pred, Alloc>& x, 
-            unordered_map<Key, T, Hash, Pred, Alloc>&& y);
-
-template <class Key, class T, class Hash, class Pred, class Alloc> 
-  void swap(unordered_map<Key, T, Hash, Pred, Alloc>&& x, 
-            unordered_map<Key, T, Hash, Pred, Alloc>& y);
-
-template <class Key, class T, class Hash, class Pred, class Alloc> 
-  void swap(unordered_multimap<Key, T, Hash, Pred, Alloc>& x, 
-            unordered_multimap<Key, T, Hash, Pred, Alloc>& y);
-
-template <class Key, class T, class Hash, class Pred, class Alloc> 
-  void swap(unordered_multimap<Key, T, Hash, Pred, Alloc>& x, 
-            unordered_multimap<Key, T, Hash, Pred, Alloc>&& y);
-
-template <class Key, class T, class Hash, class Pred, class Alloc> 
-  void swap(unordered_multimap<Key, T, Hash, Pred, Alloc>&& x, 
-            unordered_multimap<Key, T, Hash, Pred, Alloc>& y);
-
-...
-
-template <class Value, class Hash, class Pred, class Alloc> 
-  void swap(unordered_set<Value, Hash, Pred, Alloc>& x, 
-            unordered_set<Value, Hash, Pred, Alloc>& y); 
-
-template <class Value, class Hash, class Pred, class Alloc> 
-  void swap(unordered_set<Value, Hash, Pred, Alloc>& x, 
-            unordered_set<Value, Hash, Pred, Alloc>&& y);
-
-template <class Value, class Hash, class Pred, class Alloc> 
-  void swap(unordered_set<Value, Hash, Pred, Alloc>&& x, 
-            unordered_set<Value, Hash, Pred, Alloc>& y);
-
-template <class Value, class Hash, class Pred, class Alloc> 
-  void swap(unordered_multiset<Value, Hash, Pred, Alloc>& x, 
-            unordered_multiset<Value, Hash, Pred, Alloc>& y);
-
-template <class Value, class Hash, class Pred, class Alloc> 
-  void swap(unordered_multiset<Value, Hash, Pred, Alloc>& x, 
-            unordered_multiset<Value, Hash, Pred, Alloc>&& y);
-
-template <class Value, class Hash, class Pred, class Alloc> 
-  void swap(unordered_multiset<Value, Hash, Pred, Alloc>&& x, 
-            unordered_multiset<Value, Hash, Pred, Alloc>& y);
-
      -

      unordered_map

      @@ -6195,29 +4110,14 @@ Change 23.5.1 [unord.map]: // modifiers std::pair<iterator, bool> insert(const value_type& obj); template <class P> pair<iterator, bool> insert(P&& obj); - iterator insert(iterator hint, const value_type& obj); - template <class P> iterator insert(iterator hint, P&& obj); - const_iterator insert(const_iterator hint, const value_type& obj); - template <class P> const_iterator insert(const_iterator hint, P&& obj); - ... - void swap(unordered_map&&); + iterator insert(const_iterator hint, const value_type& obj); + template <class P> iterator insert(const_iterator hint, P&& obj); ... mapped_type& operator[](const key_type& k); mapped_type& operator[](key_type&& k); ... }; -template <class Key, class T, class Hash, class Pred, class Alloc> - void swap(unordered_map<Key, T, Hash, Pred, Alloc>& x, - unordered_map<Key, T, Hash, Pred, Alloc>& y); - -template <class Key, class T, class Hash, class Pred, class Alloc> - void swap(unordered_map<Key, T, Hash, Pred, Alloc>& x, - unordered_map<Key, T, Hash, Pred, Alloc>&& y); - -template <class Key, class T, class Hash, class Pred, class Alloc> - void swap(unordered_map<Key, T, Hash, Pred, Alloc>&& x, - unordered_map<Key, T, Hash, Pred, Alloc>& y);

      @@ -6288,10 +4188,8 @@ Add new section [unord.map.modifiers]: 

      pair<iterator, bool> insert(const value_type& x);
 template <class P> pair<iterator, bool> insert(P&& x);
-iterator       insert(iterator hint, const value_type& x);
-template <class P> iterator       insert(iterator hint, P&& x);
-const_iterator insert(const_iterator hint, const value_type& x);
-template <class P> const_iterator insert(const_iterator hint, P&& x);
+iterator       insert(const_iterator hint, const value_type& x);
+template <class P> iterator       insert(const_iterator hint, P&& x);
 template <class InputIterator>
   void insert(InputIterator first, InputIterator last);
      @@ -6301,15 +4199,11 @@ Add new section [unord.map.modifiers]: Requires: Those signatures taking a const value_type& parameter requires both the key_type and the mapped_type to be CopyConstructible. -

      - -

      -P shall be convertible to value_type. If P is instantiated as a reference type, then the argument x is copied from. Otherwise x is considered to be an rvalue as it is converted to value_type and inserted into the unordered_map. Specifically, in such -cases CopyConstructible is not required of key_type or +cases CopyConstructible is not required for key_type or mapped_type unless the conversion from P specifically requires it (e.g. if P is a tuple<const key_type, mapped_type>, then key_type must be @@ -6328,23 +4222,6 @@ parameters requires CopyConstructible of both

      -

      -Add to 23.5.1.3 [unord.map.swap]: -

      - -
      -
      template <class Key, class T, class Hash, class Pred, class Alloc> 
-  void swap(unordered_map<Key, T, Hash, Pred, Alloc>& x, 
-            unordered_map<Key, T, Hash, Pred, Alloc>& y);
-template <class Key, class T, class Hash, class Pred, class Alloc> 
-  void swap(unordered_map<Key, T, Hash, Pred, Alloc>& x, 
-            unordered_map<Key, T, Hash, Pred, Alloc>&& y);
-template <class Key, class T, class Hash, class Pred, class Alloc> 
-  void swap(unordered_map<Key, T, Hash, Pred, Alloc>&& x, 
-            unordered_map<Key, T, Hash, Pred, Alloc>& y);
-
      -
      -

      unordered_multimap

      @@ -6363,26 +4240,11 @@ Change 23.5.2 [unord.multimap]: // modifiers iterator insert(const value_type& obj); template <class P> iterator insert(P&& obj); - iterator insert(iterator hint, const value_type& obj); - template <class P> iterator insert(iterator hint, P&& obj); - const_iterator insert(const_iterator hint, const value_type& obj); - template <class P> const_iterator insert(const_iterator hint, P&& obj); - ... - void swap(unordered_multimap&&); + iterator insert(const_iterator hint, const value_type& obj); + template <class P> iterator insert(const_iterator hint, P&& obj); ... }; -template <class Key, class T, class Hash, class Pred, class Alloc> - void swap(unordered_multimap<Key, T, Hash, Pred, Alloc>& x, - unordered_multimap<Key, T, Hash, Pred, Alloc>& y); - -template <class Key, class T, class Hash, class Pred, class Alloc> - void swap(unordered_multimap<Key, T, Hash, Pred, Alloc>& x, - unordered_multimap<Key, T, Hash, Pred, Alloc>&& y); - -template <class Key, class T, class Hash, class Pred, class Alloc> - void swap(unordered_multimap<Key, T, Hash, Pred, Alloc>&& x, - unordered_multimap<Key, T, Hash, Pred, Alloc>& y);

      @@ -6415,10 +4277,8 @@ Add new section [unord.multimap.modifiers]: 

      iterator insert(const value_type& x);
 template <class P> iterator       insert(P&& x);
-iterator       insert(iterator hint, const value_type& x);
-template <class P> iterator       insert(iterator hint, P&& x);
-const_iterator insert(const_iterator hint, const value_type& x);
-template <class P> const_iterator insert(const_iterator hint, P&& x);
+iterator       insert(const_iterator hint, const value_type& x);
+template <class P> iterator       insert(const_iterator hint, P&& x);
 template <class InputIterator>
   void insert(InputIterator first, InputIterator last);
      @@ -6428,15 +4288,11 @@ Add new section [unord.multimap.modifiers]: Requires: Those signatures taking a const value_type& parameter requires both the key_type and the mapped_type to be CopyConstructible. -

      - -

      -P shall be convertible to value_type. - If P is instantiated as a reference +If P is instantiated as a reference type, then the argument x is copied from. Otherwise x is considered to be an rvalue as it is converted to value_type and inserted into the unordered_multimap. Specifically, in such -cases CopyConstructible is not required of key_type or +cases CopyConstructible is not required for key_type or mapped_type unless the conversion from P specifically requires it (e.g. if P is a tuple<const key_type, mapped_type>, then key_type must be @@ -6454,23 +4310,6 @@ parameters requires CopyConstructible of both

      -

      -Add to 23.5.2.2 [unord.multimap.swap]: -

      - -
      -
      template <class Key, class T, class Hash, class Pred, class Alloc> 
-  void swap(unordered_multimap<Key, T, Hash, Pred, Alloc>& x, 
-            unordered_multimap<Key, T, Hash, Pred, Alloc>& y);
-template <class Key, class T, class Hash, class Pred, class Alloc> 
-  void swap(unordered_multimap<Key, T, Hash, Pred, Alloc>& x, 
-            unordered_multimap<Key, T, Hash, Pred, Alloc>&& y);
-template <class Key, class T, class Hash, class Pred, class Alloc> 
-  void swap(unordered_multimap<Key, T, Hash, Pred, Alloc>&& x, 
-            unordered_multimap<Key, T, Hash, Pred, Alloc>& y);
-
      -
      -

      unordered_set

      @@ -6489,26 +4328,10 @@ Change 23.5.3 [unord.set]: // modifiers std::pair<iterator, bool> insert(const value_type& obj); pair<iterator, bool> insert(value_type&& obj); - iterator insert(iterator hint, const value_type& obj); - iterator insert(iterator hint, value_type&& obj); - const_iterator insert(const_iterator hint, const value_type& obj); - const_iterator insert(const_iterator hint, value_type&& obj); - ... - void swap(unordered_set&&); + iterator insert(const_iterator hint, const value_type& obj); + iterator insert(const_iterator hint, value_type&& obj); ... }; - -template <class Key, class T, class Hash, class Pred, class Alloc> - void swap(unordered_set<Key, T, Hash, Pred, Alloc>& x, - unordered_set<Key, T, Hash, Pred, Alloc>& y); - -template <class Key, class T, class Hash, class Pred, class Alloc> - void swap(unordered_set<Key, T, Hash, Pred, Alloc>& x, - unordered_set<Key, T, Hash, Pred, Alloc>&& y); - -template <class Key, class T, class Hash, class Pred, class Alloc> - void swap(unordered_set<Key, T, Hash, Pred, Alloc>&& x, - unordered_set<Key, T, Hash, Pred, Alloc>& y);

      @@ -6540,10 +4363,8 @@ Add new section [unord.set.modifiers]: 

      pair<iterator, bool> insert(const value_type& x);
 pair<iterator, bool> insert(value_type&& x);
-iterator       insert(iterator hint, const value_type& x);
-iterator       insert(iterator hint, value_type&& x);
-const_iterator insert(const_iterator hint, const value_type& x);
-const_iterator insert(const_iterator hint, value_type&& x);
+iterator       insert(const_iterator hint, const value_type& x);
+iterator       insert(const_iterator hint, value_type&& x);
 template <class InputIterator>
   void insert(InputIterator first, InputIterator last);
      @@ -6567,23 +4388,6 @@ The signature taking InputIterator parameters requires
      -

      -Add to 23.5.3.2 [unord.set.swap]: -

      - -
      -
      template <class Key, class T, class Hash, class Pred, class Alloc> 
-  void swap(unordered_set<Key, T, Hash, Pred, Alloc>& x, 
-            unordered_set<Key, T, Hash, Pred, Alloc>& y);
-template <class Key, class T, class Hash, class Pred, class Alloc> 
-  void swap(unordered_set<Key, T, Hash, Pred, Alloc>& x, 
-            unordered_set<Key, T, Hash, Pred, Alloc>&& y);
-template <class Key, class T, class Hash, class Pred, class Alloc> 
-  void swap(unordered_set<Key, T, Hash, Pred, Alloc>&& x, 
-            unordered_set<Key, T, Hash, Pred, Alloc>& y);
-
      -
      -

      unordered_multiset

      @@ -6602,26 +4406,11 @@ Change 23.5.4 [unord.multiset]: // modifiers iterator insert(const value_type& obj); iterator insert(value_type&& obj); - iterator insert(iterator hint, const value_type& obj); - iterator insert(iterator hint, value_type&& obj); - const_iterator insert(const_iterator hint, const value_type& obj); - const_iterator insert(const_iterator hint, value_type&& obj); - ... - void swap(unordered_multiset&&); + iterator insert(const_iterator hint, const value_type& obj); + iterator insert(const_iterator hint, value_type&& obj); ... }; -template <class Key, class T, class Hash, class Pred, class Alloc> - void swap(unordered_multiset<Key, T, Hash, Pred, Alloc>& x, - unordered_multiset<Key, T, Hash, Pred, Alloc>& y); - -template <class Key, class T, class Hash, class Pred, class Alloc> - void swap(unordered_multiset<Key, T, Hash, Pred, Alloc>& x, - unordered_multiset<Key, T, Hash, Pred, Alloc>&& y); - -template <class Key, class T, class Hash, class Pred, class Alloc> - void swap(unordered_multiset<Key, T, Hash, Pred, Alloc>&& x, - unordered_multiset<Key, T, Hash, Pred, Alloc>& y);

      @@ -6653,10 +4442,8 @@ Add new section [unord.multiset.modifiers]: 

      iterator insert(const value_type& x);
 iterator insert(value_type&& x);
-iterator       insert(iterator hint, const value_type& x);
-iterator       insert(iterator hint, value_type&& x);
-const_iterator insert(const_iterator hint, const value_type& x);
-const_iterator insert(const_iterator hint, value_type&& x);
+iterator       insert(const_iterator hint, const value_type& x);
+iterator       insert(const_iterator hint, value_type&& x);
 template <class InputIterator>
   void insert(InputIterator first, InputIterator last);
      @@ -6680,23 +4467,6 @@ The signature taking InputIterator parameters requires
      -

      -Add to 23.5.4.2 [unord.multiset.swap]: -

      - -
      -
      template <class Key, class T, class Hash, class Pred, class Alloc> 
-  void swap(unordered_multiset<Key, T, Hash, Pred, Alloc>& x, 
-            unordered_multiset<Key, T, Hash, Pred, Alloc>& y);
-template <class Key, class T, class Hash, class Pred, class Alloc> 
-  void swap(unordered_multiset<Key, T, Hash, Pred, Alloc>& x, 
-            unordered_multiset<Key, T, Hash, Pred, Alloc>&& y);
-template <class Key, class T, class Hash, class Pred, class Alloc> 
-  void swap(unordered_multiset<Key, T, Hash, Pred, Alloc>&& x, 
-            unordered_multiset<Key, T, Hash, Pred, Alloc>& y);
-
      -
      -

      [ @@ -6746,231 +4516,10 @@ Solved by -

      -

      696. istream::operator>>(int&) broken

      -

      Section: 27.7.1.2.2 [istream.formatted.arithmetic] Status: Ready - Submitter: Martin Sebor Opened: 2007-06-23 Last modified: 2009-07-15

      -

      View all other issues in [istream.formatted.arithmetic].

      -

      View all issues with Ready status.

      -

      Discussion:

      -

      -From message c++std-lib-17897: -

      -

      -The code shown in 27.7.1.2.2 [istream.formatted.arithmetic] as the "as if" -implementation of the two arithmetic extractors that don't have a -corresponding num_get interface (i.e., the -short and int overloads) is subtly buggy in -how it deals with EOF, overflow, and other similar -conditions (in addition to containing a few typos). -

      -

      -One problem is that if num_get::get() reaches the EOF -after reading in an otherwise valid value that exceeds the limits of -the narrower type (but not LONG_MIN or -LONG_MAX), it will set err to -eofbit. Because of the if condition testing for -(err == 0), the extractor won't set -failbit (and presumably, return a bogus value to the -caller). -

      -

      -Another problem with the code is that it never actually sets the -argument to the extracted value. It can't happen after the call to -setstate() since the function may throw, so we need to -show when and how it's done (we can't just punt as say: "it happens -afterwards"). However, it turns out that showing how it's done isn't -quite so easy since the argument is normally left unchanged by the -facet on error except when the error is due to a misplaced thousands -separator, which causes failbit to be set but doesn't -prevent the facet from storing the value. -

      - -

      [ -Batavia (2009-05): -]

      - -
      -

      -We believe this part of the Standard has been recently adjusted -and that this issue was addressed during that rewrite. -

      -

      -Move to NAD. -

      -
      - -

      [ -2009-05-28 Howard adds: -]

      - - -
      -

      -I've moved this issue from Tentatively NAD to Open. -

      - -

      -The current wording of -N2857 -in 22.4.2.1.2 [facet.num.get.virtuals] p3, stage 3 appears to indicate that -in parsing arithmetic types, the value is always set, but sometimes in addition -to setting failbit. -

      - -
        -
      • -If there is a range error, the value is set to min or max, else -
        • -
      • -if there is a conversion error, the value is set to 0, else -
        • -
      • -if there is a grouping error, the value is set to whatever it would be if grouping were ignored, else -
        • -
      • -the value is set to its error-free result. -
        • -
      - -

      -However there is a contradictory sentence in 22.4.2.1.2 [facet.num.get.virtuals] p1. -

      - -

      -27.7.1.2.2 [istream.formatted.arithmetic] should mimic the behavior of 22.4.2.1.2 [facet.num.get.virtuals] -(whatever we decide that behavior is) for -int and short, and currently does not. I believe that the -correct code fragment should look like: -

      - -
      typedef num_get<charT,istreambuf_iterator<charT,traits> > numget;
-iostate err = ios_base::goodbit;
-long lval;
-use_facet<numget>(loc).get(*this, 0, *this, err, lval);
-if (lval < numeric_limits<int>::min())
-{
-  err |= ios_base::failbit;
-  val = numeric_limits<int>::min();
-}
-else if (lval > numeric_limits<int>::max())
-{
-  err |= ios_base::failbit;
-  val = numeric_limits<int>::max();
-}
-else
-  val = static_cast<int>(lval);
-setstate(err);
-
      -
      - -

      [ -2009-07 Frankfurt -]

      - - -
      -Move to Ready. -
      - - - -

      Proposed resolution:

      -

      -Change 22.4.2.1.2 [facet.num.get.virtuals], p1: -

      - -
      --1- Effects: Reads characters from in, interpreting them -according to str.flags(), use_facet<ctype<charT> ->(loc), and use_facet< numpunct<charT> ->(loc), where loc is str.getloc(). If an error -occurs, val is unchanged; otherwise it is set to the resulting value. -
      - -

      -Change 27.7.1.2.2 [istream.formatted.arithmetic], p2 and p3: -

      - -
      -
      operator>>(short& val);
-
      -
      -

      --2- The conversion occurs as if performed by the following code fragment (using the same notation as for -the preceding code fragment): -

      - -
      typedef num_get<charT,istreambuf_iterator<charT,traits> > numget;
-iostate err = iostate_base::goodbit;
-long lval;
-use_facet<numget>(loc).get(*this, 0, *this, err, lval);
-if (err != 0)
-  ;
-else if (lval < numeric_limits<short>::min()
-  || numeric_limits<short>::max() < lval)
-     err = ios_base::failbit;
-if (lval < numeric_limits<short>::min())
-{
-  err |= ios_base::failbit;
-  val = numeric_limits<short>::min();
-}
-else if (lval > numeric_limits<short>::max())
-{
-  err |= ios_base::failbit;
-  val = numeric_limits<short>::max();
-}
-else
-  val = static_cast<short>(lval);
-setstate(err);
-
      - -
      - -
      operator>>(int& val);
-
      -
      -

      --3- The conversion occurs as if performed by the following code fragment (using the same notation as for -the preceding code fragment): -

      - -
      typedef num_get<charT,istreambuf_iterator<charT,traits> > numget;
-iostate err = iostate_base::goodbit;
-long lval;
-use_facet<numget>(loc).get(*this, 0, *this, err, lval);
-if (err != 0)
-  ;
-else if (lval < numeric_limits<int>::min()
-  || numeric_limits<int>::max() < lval)
-     err = ios_base::failbit;
-if (lval < numeric_limits<int>::min())
-{
-  err |= ios_base::failbit;
-  val = numeric_limits<int>::min();
-}
-else if (lval > numeric_limits<int>::max())
-{
-  err |= ios_base::failbit;
-  val = numeric_limits<int>::max();
-}
-else
-  val = static_cast<int>(lval);
-setstate(err);
-
      - -
      - -
      - - - - -

      704. MoveAssignable requirement for container value type overly strict

      Section: 23.2 [container.requirements] Status: Open - Submitter: Howard Hinnant Opened: 2007-05-20 Last modified: 2009-07-20

      + Submitter: Howard Hinnant Opened: 2007-05-20 Last modified: 2009-10-20

      View other active issues in [container.requirements].

      View all other issues in [container.requirements].

      View all issues with Open status.

      @@ -7139,6 +4688,15 @@ MoveConstructible, etc.

      +

      [ +2009-10 Santa Cruz: +]

      + + +
      +Leave open. Howard to provide wording. +
      +

      Proposed resolution:

      @@ -7161,481 +4719,10 @@ Solved by -
      -

      711. Contradiction in empty shared_ptr

      -

      Section: 20.8.10.2.5 [util.smartptr.shared.obs] Status: Ready - Submitter: Peter Dimov Opened: 2007-08-24 Last modified: 2009-07-17

      -

      View all other issues in [util.smartptr.shared.obs].

      -

      View all issues with Ready status.

      -

      Discussion:

      -

      -A discussion on -comp.std.c++ -has identified a contradiction in the shared_ptr specification. -The note: -

      - -

      -[ Note: this constructor allows creation of an empty shared_ptr instance with a non-NULL stored pointer. --end note ] -

      - -

      -after the aliasing constructor -

      - -
      template<class Y> shared_ptr(shared_ptr<Y> const& r, T *p);
-
      - -

      -reflects the intent of -N2351 -to, well, allow the creation of an empty shared_ptr -with a non-NULL stored pointer. -

      - -

      -This is contradicted by the second sentence in the Returns clause of 20.8.10.2.5 [util.smartptr.shared.obs]: -

      - -
      -
      T* get() const;
-
      -

      -Returns: the stored pointer. Returns a null pointer if *this is empty. -

      -
      - -

      [ -Bellevue: -]

      - - -
      -

      -Adopt option 1 and move to review, not ready. -

      -

      -There was a lot of confusion about what an empty shared_ptr is (the term -isn't defined anywhere), and whether we have a good mental model for how -one behaves. We think it might be possible to deduce what the definition -should be, but the words just aren't there. We need to open an issue on -the use of this undefined term. (The resolution of that issue might -affect the resolution of issue 711.) -

      -

      -The LWG is getting more uncomfortable with the aliasing proposal (N2351) -now that we realize some of its implications, and we need to keep an eye -on it, but there isn't support for removing this feature at this time. -

      -
      - -

      [ -Sophia Antipolis: -]

      - - -
      -

      -We heard from Peter Dimov, who explained his reason for preferring solution 1. -

      -

      -Because it doesn't seem to add anything. It simply makes the behavior -for p = 0 undefined. For programmers who don't create empty pointers -with p = 0, there is no difference. Those who do insist on creating them -presumably have a good reason, and it costs nothing for us to define the -behavior in this case. -

      -

      -The aliasing constructor is sharp enough as it is, so "protecting" users -doesn't make much sense in this particular case. -

      -

      -> Do you have a use case for r being empty and r being non-null? -

      -

      -I have received a few requests for it from "performance-conscious" -people (you should be familiar with this mindset) who don't like the -overhead of allocating and maintaining a control block when a null -deleter is used to approximate a raw pointer. It is obviously an "at -your own risk", low-level feature; essentially a raw pointer behind a -shared_ptr facade. -

      -

      -We could not agree upon a resolution to the issue; some of us thought -that Peter's description above is supporting an undesirable behavior. -

      -
      - -

      [ -2009-07 Frankfurt: -]

      - - -
      -

      -We favor option 1, move to Ready. -

      -

      [ -Howard: Option 2 commented out for clarity, and can be brought back. -]

      - -
      - - - -

      Proposed resolution:

      -

      -In keeping the N2351 spirit and obviously my preference, change 20.8.10.2.5 [util.smartptr.shared.obs]: -

      - -
      -
      T* get() const;
-
      -

      -Returns: the stored pointer. Returns a null pointer if *this is empty. -

      -
      - - - - - - - - -
      -

      716. Production in [re.grammar] not actually modified

      -

      Section: 28.13 [re.grammar] Status: Ready - Submitter: Stephan T. Lavavej Opened: 2007-08-31 Last modified: 2009-07-16

      -

      View all issues with Ready status.

      -

      Discussion:

      -

      -TR1 7.13 [tr.re.grammar]/3 and C++0x WP 28.13 [re.grammar]/3 say: -

      - -
      -

      -The following productions within the ECMAScript grammar are modified as follows: -

      - -
      CharacterClass ::
-[ [lookahead ∉ {^}] ClassRanges ]
-[ ^ ClassRanges ]
-
      - -
      - -

      -This definition for CharacterClass appears to be exactly identical to that in ECMA-262. -

      - -

      -Was an actual modification intended here and accidentally omitted, or was this production accidentally included? -

      - -

      [ -Batavia (2009-05): -]

      - -
      -

      -We agree that what is specified is identical to what ECMA-262 specifies. -Pete would like to take a bit of time to assess whether we had intended, -but failed, to make a change. -It would also be useful to hear from John Maddock on the issue. -

      -

      -Move to Open. -

      -
      - -

      [ -2009-07 Frankfurt: -]

      - - -
      -Move to Ready. -
      - - - -

      Proposed resolution:

      -

      -Remove this mention of the CharacterClass production. -

      - -
      CharacterClass ::
-[ [lookahead ∉ {^}] ClassRanges ]
-[ ^ ClassRanges ]
-
      - - - - - - -
      -

      719. std::is_literal type traits should be provided

      -

      Section: 20.6 [meta] Status: Open - Submitter: Daniel Krügler Opened: 2007-08-25 Last modified: 2009-07-16

      -

      View other active issues in [meta].

      -

      View all other issues in [meta].

      -

      View all issues with Open status.

      -

      Duplicate of: 750

      -

      Discussion:

      -

      -Since the inclusion of constexpr in the standard draft N2369 we have -a new type category "literal", which is defined in 3.9 [basic.types]/p.11: -

      - -
      -

      --11- A type is a literal type if it is: -

      -
        -
      • a scalar type; or
        • -

      • a class type (clause 9) with

        -
          -
        • a trivial copy constructor,
          • -
        • a trivial destructor,
          • -
        • at least one constexpr constructor other than the copy constructor,
          • -
        • no virtual base classes, and
          • -
        • all non-static data members and base classes of literal types; or
          • -
        -
        • -
      • an array of literal type.
        • -
      -
      - -

      -I strongly suggest that the standard provides a type traits for -literal types in 20.6.4.3 [meta.unary.prop] for several reasons: -

      - -
        -
      1. To keep the traits in sync with existing types.
        2. -
      2. I see many reasons for programmers to use this trait in template - code to provide optimized template definitions for these types, - see below.
        3. -
      3. A user-provided definition of this trait is practically impossible -to write portably.
        4. -
      - -

      -The special problem of reason (c) is that I don't see currently a -way to portably test the condition for literal class types: -

      - -
      -
        -
      • at least one constexpr constructor other than the copy constructor,
        • -
      -
      - - - -

      [ -Alisdair is considering preparing a paper listing a number of missing -type traits, and feels that it might be useful to handle them all -together rather than piecemeal. This would affect issue 719 and 750. -These two issues should move to OPEN pending AM paper on type traits. -]

      - - -

      [ -2009-07 Frankfurt: -]

      - - -
      -Beman, Daniel, and Alisdair will work on a paper proposing new type traits. -
      - - -

      Proposed resolution:

      -

      -In 20.6.2 [meta.type.synop] in the group "type properties", -just below the line -

      - -
      template <class T> struct is_pod;
-
      - -

      -add a new one: -

      - -
      template <class T> struct is_literal;
-
      - -

      -In 20.6.4.3 [meta.unary.prop], table Type Property Predicates, just -below the line for the is_pod property add a new line: -

      - -
    + *r = o - + result is not used -   -  + +Post: r is not required to be dereferenceable. r is incrementable. +
    + ++r - + X& -   + &r == &++r -
    + r++ - -convertible to const X& - -{X tmp = r;
    ++r;
    return tmp;}     -    		 -  +convertible to const X& + +{X tmp = r;
    ++r;
    return tmp;}     +    		 + +Post: r is dereferenceable, unless otherwise specified. r is not required to be incrementable. +
    -*r++ = o
    *r = o, ++r
    *r = o, r++     +*r++ = o;     		-result is not used usable +result is not used   -Note: only these forms permitted +
    - - - - - - - - -
    TemplateConditionPreconditions
    template <class T> struct is_literal;T is a literal type (3.9)T shall be a complete type, an -array of unknown bound, or -(possibly cv-qualified) void.
    - - - - - - -
    -

    723. basic_regex should be moveable

    -

    Section: 28.8 [re.regex] Status: Ready - Submitter: Daniel Krügler Opened: 2007-08-29 Last modified: 2009-07-16

    -

    View all other issues in [re.regex].

    -

    View all issues with Ready status.

    -

    Discussion:

    - -

    Addresses UK 316

    - -

    -According to the current state of the standard draft, the class -template basic_regex, as described in 28.8 [re.regex]/3, is -neither MoveConstructible nor MoveAssignable. -IMO it should be, because typical regex state machines tend -to have a rather large data quantum and I have seen several -use cases, where a factory function returns regex values, -which would take advantage of moveabilities. -

    - -

    [ -Sophia Antipolis: -]

    - - -
    -Needs wording for the semantics, the idea is agreed upon. -
    - -

    [ -Post Summit Daniel updated wording to reflect new "swap rules". -]

    - - -

    [ -2009-07 Frankfurt: -]

    - - -
    -Move to Ready. -
    - - - -

    Proposed resolution:

    -

    -In the class definition of basic_regex, just below 28.8 [re.regex]/3, -perform the following changes: -

    - -
      -
    1. -

      -Just after basic_regex(const basic_regex&); insert: -

      - -
      basic_regex(basic_regex&&);
-
      -
      2. -
    2. -

      -Just after basic_regex& operator=(const basic_regex&); insert: -

      -
      basic_regex& operator=(basic_regex&&);
-
      -
      3. -
    3. -

      -Just after basic_regex& assign(const basic_regex& that); insert: -

      -
      basic_regex& assign(basic_regex&& that);
-
      -
      4. -
    4. -

      -In 28.8.2 [re.regex.construct], just after p.11 add the following -new member definition: -

      -
      basic_regex(basic_regex&& e);
-
      -
      -

      -Effects: Move-constructs a basic_regex instance from e. -

      -

      -Postconditions: flags() and mark_count() return e.flags() and -e.mark_count(), respectively, -that e had before construction, leaving -e in a valid state with an unspecified value. -

      -

      -Throws: nothing. -

      -
      -
      -
      5. -
    5. -

      -Also in 28.8.2 [re.regex.construct], just after p.18 add the -following new member definition: -

      - -
      basic_regex& operator=(basic_regex&& e);
-
      -
      -Effects: Returns the result of assign(std::move(e)). -
      -
      -
      6. -
    6. -

      -In 28.8.3 [re.regex.assign], just after p. 2 add the following new -member definition: -

      -
      basic_regex& assign(basic_regex&& rhs);
-
      -
      -

      -Effects: Move-assigns a basic_regex instance from rhs and returns *this. -

      -

      -Postconditions: flags() and mark_count() return rhs.flags() -and rhs.mark_count(), respectively, that -rhs had before assignment, leaving rhs -in a valid state with an unspecified value. -

      -

      -Throws: nothing. -

      -
      -
      -
      7. -
    - - - - -

    724. DefaultConstructible is not defined

    -

    Section: X [utility.arg.requirements] Status: Open - Submitter: Pablo Halpern Opened: 2007-09-12 Last modified: 2009-07-28

    +

    Section: 20.2.1 [utility.arg.requirements] Status: Open + Submitter: Pablo Halpern Opened: 2007-09-12 Last modified: 2009-10-23

    View other active issues in [utility.arg.requirements].

    View all other issues in [utility.arg.requirements].

    View all issues with Open status.

    @@ -7689,15 +4776,91 @@ Move to open, as no-one happy to produce wording on the fly. ]

    +

    [ +2009-08-17 Daniel adds "[defaultconstructible]" to table title. 408 +depends upon this issue. +]

    + + +

    [ +2009-08-18 Alisdair adds: +]

    + + +
    +

    +Looking at the proposed table in this issue, it really needs two rows: +

    + +
    + + + + + + + + + + + + + +
    Table 33: DefaultConstructible requirements [defaultconstructible]
    expressionpost-condition
    T t;t is default-initialized.
    T{}Object of type T is value-initialized.
    +
    + +

    +Note I am using the new brace-initialization syntax that is unambiguous +in all use cases (no most vexing parse.) +

    +
    + +

    [ +2009-10-03 Daniel adds: +]

    + + +
    +

    +The suggested definition T{} describing it as +value-initialization is wrong, because it belongs to list-initialization +which would - as the current rules are - always prefer a +initializer-list constructor over a default-constructor. I don't +consider this as an appropriate definition of +DefaultConstructible. My primary suggestion is to ask core, +whether the special case T{} (which also easily leads to +ambiguity situations for more than one initializer-list in a class) +would always prefer a default-constructor - if any - before considering +an initializer-list constructor or to provide another syntax form to +prefer value-initialization over list-initialization. If that fails I +would fall back to suggest to use the expression T() instead of +T{} with all it's disadvantages for the meaning of the +expression +

    + +
    T t();
+
    +
    + +

    [ +2009-10 Santa Cruz: +]

    + + +
    +Leave Open. Core is looking to make Alisdair's proposed +resolution correct. +
    +

    Proposed resolution:

    -In section X [utility.arg.requirements], before table 33, add the +In section 20.2.1 [utility.arg.requirements], before table 33, add the following table:

    -

    Table 33: DefaultConstructible requirements

    +

    Table 33: DefaultConstructible requirements [defaultconstructible]

    @@ -7744,7 +4907,7 @@ We believe concepts will solve this problem

    726. Missing regex_replace() overloads

    Section: 28.11.4 [re.alg.replace] Status: Open - Submitter: Stephan T. Lavavej Opened: 2007-09-22 Last modified: 2009-07-25

    + Submitter: Stephan T. Lavavej Opened: 2007-09-22 Last modified: 2009-10-23

    View other active issues in [re.alg.replace].

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    @@ -7851,6 +5014,16 @@ This is solved by the proposed resolution of 727. +
    +

    Proposed resolution:

    @@ -7926,11 +5099,11 @@ charT* str     and const charT* fmt). 28.11.4 [re.alg.replace]:

    727. regex_replace() doesn't accept basic_strings with custom traits and allocators

    -

    Section: 28.11.4 [re.alg.replace] Status: Open - Submitter: Stephan T. Lavavej Opened: 2007-09-22 Last modified: 2009-07-31

    +

    Section: 28.11.4 [re.alg.replace] Status: Review + Submitter: Stephan T. Lavavej Opened: 2007-09-22 Last modified: 2009-10-23

    View other active issues in [re.alg.replace].

    View all other issues in [re.alg.replace].

    -

    View all issues with Open status.

    +

    View all issues with Review status.

    Discussion:

    regex_match() and regex_search() take const basic_string<charT, ST, @@ -8014,6 +5187,15 @@ in the Proposed Resolution. ]

    +

    [ +2009-10 Santa Cruz: +]

    + + +
    +Move to Review. Chair is anxious to move this to Ready in Pittsburgh. +
    +

    Proposed resolution:

    @@ -8143,7 +5325,7 @@ template <class OutputIter>

    1 Requires: The type OutputIter shall satisfy the requirements for an -Output Iterator (24.2.3 [output.iterators]). +Output Iterator (24.2.2 [output.iterators]).

    @@ -8223,7 +5405,7 @@ in fmt with either the character(s) it represents or the sequence of characters within *this to which it refers. The bitmasks specified in flags determines what format specifiers and escape sequences are -recognized. Constructs an empty string result of type +recognized. Constructs an empty string result of type basic_string<char_type, ST, SA>, and calls format(back_inserter(result), fmt, flags).

    @@ -8249,7 +5431,7 @@ string_type

    -Effects: Constructs an empty string result of type string_type, and calls +Effects: Constructs an empty string result of type string_type, and calls format(back_inserter(result), fmt, fmt + char_traits<char_type>::length(fmt), flags).

    @@ -8326,7 +5508,7 @@ template <class traits, class charT, class ST, class SA>
    -Effects: Constructs an empty string result of type basic_string<charT, +Effects: Constructs an empty string result of type basic_string<charT, ST, SA>, calls regex_replace(back_inserter(result), s.begin(), s.end(), e, fmt, flags), and then returns result.
    @@ -8360,7 +5542,7 @@ template <class traits, class charT>
    -Effects: Constructs an empty string result of type basic_string<charT>, +Effects: Constructs an empty string result of type basic_string<charT>, calls regex_replace(back_inserter(result), s, s + char_traits<charT>::length(s), e, fmt, flags), and then returns result. @@ -8379,8 +5561,8 @@ e, fmt, flags), and then returns result.

    742. Enabling swap for proxy iterators

    -

    Section: X [utility.arg.requirements] Status: Open - Submitter: Howard Hinnant Opened: 2007-10-10 Last modified: 2009-07-28

    +

    Section: 20.2.1 [utility.arg.requirements] Status: Open + Submitter: Howard Hinnant Opened: 2007-10-10 Last modified: 2009-11-08

    View other active issues in [utility.arg.requirements].

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    @@ -8482,11 +5664,31 @@ satisfies the semantics of swapping? ]

    +

    [ +2009-10 Santa Cruz: +]

    + + +
    +Leave as Open. Dave to provide wording. +
    + +

    [ +2009-11-08 Howard adds: +]

    + + +
    +Updated wording to sync with +N3000. +Also this issue is very closely related to 594. +
    +

    Proposed resolution:

    -Change X [utility.arg.requirements]: +Change 20.2.1 [utility.arg.requirements]:

    @@ -8504,7 +5706,7 @@ rvalue of type T; w is a value of type T; and Table 37: Swappable requirements [swappable] -expressionreturn typepost-condition +expressionReturn typePost-condition swap(sw,tv)void tw has the value originally held by uv, and @@ -8518,19 +5720,22 @@ The Swappable requirement is met by satisfying one or more of the follo
  • T is Swappable if T and V are the same type and T satisfies the -CopyConstructible -MoveConstructible requirements (Table 34 -33) and the CopyAssignable -MoveAssignable requirements (Table 36 -35); +MoveConstructible requirements (Table +33) and the +MoveAssignable requirements (Table +35);
  • T is Swappable with V if a namespace scope function named swap exists in the same namespace as the definition of T or V, such that the expression -swap(tw,u v) is valid and has the +swap(sw,t v) is valid and has the semantics described in this table.
    • +
  • +T is Swappable if T is an array type whose +element type is Swappable. +
    • @@ -8546,7 +5751,7 @@ post San Francisco:
    Solved by -N2758. +N2758.
    @@ -8557,7 +5762,7 @@ Solved by

    774. Member swap undefined for most containers

    Section: 23 [containers] Status: Open - Submitter: Alisdair Meredith Opened: 2008-01-14 Last modified: 2009-07-30

    + Submitter: Alisdair Meredith Opened: 2008-01-14 Last modified: 2009-10-31

    View other active issues in [containers].

    View all other issues in [containers].

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    @@ -8643,7 +5848,7 @@ is no longer applicable.
    1. -It assumes that the proposed resolution for 883 is applied, +It assumes that the proposed resolution for 883 is applied, which breaks the circularity of definition between member swap and free swap.
      2. @@ -8662,8 +5867,44 @@ hash functions in containers are swapped via unqualified free
    +

    [ +2009-09-30 Daniel adds: +]

    -

    Proposed resolution:

    + +
    +The outcome of this issue should be considered with the outcome of 1198 both in style and in content (e.g. bullet 9 suggests to +define the semantic of void +priority_queue::swap(priority_queue&) in terms of the member +swap of the container). +
    + +

    [ +2009-10 Santa Cruz: +]

    + + +
    +Looked at, but took no action on as it overlaps too much with +N2982. +Waiting for a new draft WP. +
    + +

    [ +2009-10 Santa Cruz: +]

    + + +
    +Leave as open. Pablo to provide wording. +
    + +

    [ +2009-10-26 Pablo updated wording. Here is the wording he replaced: +]

    + + +

    1. @@ -8730,7 +5971,7 @@ Insert a new paragraph just after 23.3 [sequences]/1:

      In addition to being available via inclusion of the <algorithm> header, -the swap function templates in 25.4.3 [alg.swap] are also available when the +the swap function templates in 25.3.3 [alg.swap] are also available when the header <queue> is included.
      @@ -8926,7 +6167,7 @@ Insert a new paragraph just before 23.4 [associative]/1:
      In addition to being available via inclusion of the <algorithm> header, -the swap function templates in 25.4.3 [alg.swap] are also available when any of the +the swap function templates in 25.3.3 [alg.swap] are also available when any of the headers <map> or <set> are included.
      2. @@ -9106,7 +6347,7 @@ Insert a new paragraph just before 23.5 [unord]/1:
      In addition to being available via inclusion of the <algorithm> header, -the swap function templates in 25.4.3 [alg.swap] are also available when any of the +the swap function templates in 25.3.3 [alg.swap] are also available when any of the headers <unordered_map> or <unordered_set> are included.
      @@ -9238,6 +6479,188 @@ and an unqualified swap of the Hash objects of *this
    +
    + +

    [ +2009-10-30 Pablo and Daniel updated wording. +]

    + + + + +

    Proposed resolution:

    + +

    [ +This resolution is based on the September 2009 WP, +N2960, +except that it +assumes that +N2982 +and issues 883 and 1232 have already been applied. Note in +particular that Table 91 in +N2960 +is refered to as Table 90 because +N2982 +removed the old Table 90. This resolution also addresses issue 431. +]

    + +

    +In 23.2.1 [container.requirements.general], replace the a.swap(b) row in table 90, +"container requirements" (was table 91 before the application of N2982 to the +WP): +

    +
    + + + + + + + + + + + + + + + +
    a.swap(b)void   swap(a,b)Exchange the contents of a and b.(Note A)
    swap(a,b)void   a.swap(b)(Note A)
    +
    +

    +Modify the notes immediately following Table 90 in +23.2.1 [container.requirements.general] as follows (The wording below is after the +application of N2982 to N2960. The editor might also want to combine Notes +A and B into one.): +

    +

    +Notes: the algorithms swap(), equal() and lexicographical_compare() +are defined in Clause 25. Those entries marked "(Note A)" or "(Note B)" +should have linear complexity for array and constant +complexity for all other standard containers. +

    +

    +In 23.2.1 [container.requirements.general], after paragraph 9, add: +

    +

    +The expression a.swap(b), for containers a +and b of a standard container type other than array, +exchanges the values of a and b without invoking any +move, copy, or swap operations on the individual container elements. +Any Compare, Pred, or Hash function +objects belonging to a and b shall satisfy +the Swappable requirements and are exchanged by unqualified calls +to non-member swap. If +allocator_traits<allocator_type>::propagate_on_container_swap::value +== true, then the allocators of a and b are +also exchanged using an unqualified call to non-member swap. +Otherwise, the behavior is undefined unless a.get_allocator() == +b.get_allocator(). Each iterator refering to an element in one +container before the swap shall refer to the same element in the other +container after the swap. It is unspecified whether an iterator with +value a.end() before the swap will have +value b.end() after the swap. In addition to being available via +inclusion of the <utility> header, the swap +function template in 25.3.3 [alg.swap] is also available within the definition of +every standard container's swap function. +

    +

    [ +Note to the editor: Paragraph 2 starts with a sentence fragment, +clearly from an editing or source-control error. +]

    + +

    +Modify 23.2.4.1 [associative.reqmts.except] as follows: +

    +
    +

    +23.2.4.1 Exception safety guarantees 23.2.4.1 [associative.reqmts.except] +

    +

    +For associative containers, no clear() function throws an +exception. erase(k) does not throw an exception unless that +exception is thrown by the +container's PredCompare object (if any). +

    +

    +For associative containers, if an exception is thrown by any operation from +within an insert() function inserting a single element, +the insert() function has no effect. +

    +

    +For associative containers, no swap function throws an exception +unless that exception is thrown by the copy constructor +or copy assignment operatorswap of the +container's PredCompare object (if any). +

    +

    +Modify 23.2.5.1 [unord.req.except], paragraph 3 as follows: +

    +

    +For unordered associative containers, no swap function throws an +exception unless that exception is thrown by the copy constructor or copy +assignment operatorswap of the container's Hash +or Pred object (if any). +

    +

    +Modify section 23.3.1.2 [array.special]: +

    +
    +

    +array specialized algorithms 23.3.1.2 [array.special] +

    +

    +template <class T, size_t N> void swap(array<T,N>& x,array<T,N>& y); +

    +
    +

    +Effects: swap_ranges(x.begin(), x.end(), y.begin() );x.swap(y); +

    +
    +
    +

    +Add a new section after 23.3.1.5 [array.fill] (Note to the editor: array::fill make use +of a concept requirement that must be removed or changed to text.): +

    +
    +

    +array::swap [array.swap] +

    +

    +void swap(array& y); +

    +
    +

    +Effects: swap_ranges(this->begin(), this->end(), y.begin() ); +

    +

    +Throws: Nothing unless one of the element-wise swap calls throws an +exception. +

    +

    +[Note: Unlike other containers' swap functions, +array::swap takes linear, not constant, time, may exit via an +exception, and does not cause iterators to become associated with the other +container. — end note] +

    +
    +
    + +

    +Insert a new paragraph just after 23.3.5 [container.adaptors]/1: +

    +

    +For container adaptors, no swap function throws an exception +unless that exception is thrown by the swap of the +adaptor's Container or Compare object (if any). +

    + + + + + + + @@ -9245,16 +6668,16 @@ and an unqualified swap of the Hash objects of *this

    780. std::merge() specification incorrect/insufficient

    -

    Section: 25.5.4 [alg.merge] Status: Ready - Submitter: Daniel Krügler Opened: 2008-01-25 Last modified: 2009-07-16

    -

    View all issues with Ready status.

    +

    Section: 25.4.4 [alg.merge] Status: Review + Submitter: Daniel Krügler Opened: 2008-01-25 Last modified: 2009-10-22

    +

    View all issues with Review status.

    Discussion:

    Though issue 283 has fixed many open issues, it seems that some are still open:

    -Both 25.3.4 [lib.alg.merge] in 14882:2003 and 25.5.4 [alg.merge] in N2461 +Both 25.3.4 [lib.alg.merge] in 14882:2003 and 25.4.4 [alg.merge] in N2461 have no Requires element and the Effects element contains some requirements, which is probably editorial. Worse is that:

    @@ -9344,161 +6767,100 @@ Move to Review. Move to Ready.
    - - -

    Proposed resolution:

    -

    -In 25.5.4 [alg.merge] replace p.1+ 2: -

    - -
    -

    -Effects: Merges Copies all the elements of the two sorted ranges [first1,last1) and -[first2,last2) into the range -[result,result + (last1 - first1) + (last2 - first2)) -[result, last) (where last is equal to result + (last1 -- first1) + (last2 - first2)), such that resulting range will be -sorted in non-decreasing order; that is, for every iterator i in -[result,last) other than result, the condition *i < *(i - 1) or, -respectively, comp(*i, *(i - 1)) will be false. -

    - -

    -Requires: The resulting range shall not overlap with either of the original ranges. The list will be sorted in non-decreasing -order according to the ordering defined by comp; that is, for every iterator i in -[first,last) other than first, the condition *i < *(i - 1) or -comp(*i, *(i - 1)) will be false. -

    -
    - -

    -[N.B.: I attempted to reuse the wording style of inplace_merge, -therefore proposing to -insert ", respectively," between both predicate tests. This is no -strictly necessary as -other parts of <algorithm> show, just a matter of consistency] -

    - - - - - - -
    -

    788. ambiguity in [istream.iterator]

    -

    Section: 24.6.1 [istream.iterator] Status: Ready - Submitter: Martin Sebor Opened: 2008-02-06 Last modified: 2009-07-16

    -

    View other active issues in [istream.iterator].

    -

    View all other issues in [istream.iterator].

    -

    View all issues with Ready status.

    -

    Discussion:

    - -

    Addresses UK 287

    - -
    -

    -It is not clear what the initial state of an istream_iterator should be. Is -_value_ initialized by reading the stream, or default/value initialized? If -it is initialized by reading the stream, what happens if the initialization -is deferred until first dereference, when ideally the iterator value should -have been that of an end-of-stream iterator which is not safely -dereferencable? -

    - -

    -Recommendation: Specify _value_ is initialized by reading the stream, or -the iterator takes on the end-of-stream value if the stream is empty. -

    -
    - -

    -The description of how an istream_iterator object becomes an -end-of-stream iterator is a) ambiguous and b) out of date WRT -issue 468: -

    - -
    -istream_iterator reads (using operator>>) successive elements from the -input stream for which it was constructed. After it is constructed, and -every time ++ is used, the iterator reads and stores a value of T. If -the end of stream is reached (operator void*() on the stream returns -false), the iterator becomes equal to the end-of-stream iterator value. -The constructor with no arguments istream_iterator() always constructs -an end of stream input iterator object, which is the only legitimate -iterator to be used for the end condition. The result of operator* on an -end of stream is not defined. For any other iterator value a const T& is -returned. The result of operator-> on an end of stream is not defined. -For any other iterator value a const T* is returned. It is impossible to -store things into istream iterators. The main peculiarity of the istream -iterators is the fact that ++ operators are not equality preserving, -that is, i == j does not guarantee at all that ++i == ++j. Every time ++ -is used a new value is read. -
    - -

    -istream::operator void*() returns null if istream::fail() is true, -otherwise non-null. istream::fail() returns true if failbit or -badbit is set in rdstate(). Reaching the end of stream doesn't -necessarily imply that failbit or badbit is set (e.g., after -extracting an int from stringstream("123") the stream object will -have reached the end of stream but fail() is false and operator -void*() will return a non-null value). -

    - -

    -Also I would prefer to be explicit about calling fail() here -(there is no operator void*() anymore.) -

    -

    [ -Summit: -]

    - - -
    -Moved from Ready to Open for the purposes of using this issue to address NB UK 287. -Martin to handle. -
    - -

    [ -2009-07 Frankfurt: +2009-08-23 Daniel reopens: ]

    -This improves the wording. +The proposed wording must be rephrased, because the part

    + +
    +for every iterator i in [result,last) other than result, the condition +*i < *(i - 1) or, respectively, comp(*i, *(i - 1)) will be false" +
    +

    -Move to Ready. +isn't meaningful, because the range [result,last) is that of a pure +OutputIterator, which is not readable in general.

    + +

    [Howard: Proposed wording updated by Daniel, status moved from Ready to Review.]

    + +
    + +

    [ +2009-10 Santa Cruz: +]

    + + +
    +

    +Matt has some different words to propose. Those words have been moved into +the proposed wording section, and the original proposed wording now appears +here: +

    +
    +

    +In 25.4.4 [alg.merge] replace p.1+ 2: +

    + +
    +

    +Effects: MergesCopies all the elements of the +two sorted ranges +[first1,last1) and [first2,last2) into the range [result,result + +(last1 - first1) + (last2 - first2)) +, such that resulting range will be sorted in non-decreasing +order; that is for every +pair of iterators i and j of either input ranges, where *i was copied +to the output range +before *j was copied to the output range, the condition *j < *i or, +respectively, comp(*j, *i) +will be false. +

    + +

    +Requires:The resulting range shall not overlap with either +of the original ranges. +The list will be sorted in non-decreasing order according to the +ordering defined by +comp; that is, for every iterator i in [first,last) other than first, +the condition *i < *(i - 1) or +comp(*i, *(i - 1)) will be false. +

    +
    +

    Proposed resolution:

    +

    +Effects: Merges two sorted ranges [first1,last1) and +[first2,last2) into the range [result, result + (last1 - +first1) + (last2 - first2)). +

    +

    +Effects: Copies all the elements of the two sorted ranges +[first1,last1) and [first2,last2) into the range +[result, result_last), where result_last is result ++ (last1 - first1) + (last2 - first2), such that the resulting +range satisfies is_sorted(result, result_last) or +is_sorted(result, result_last, comp), respectively. +

    +

    -Change 24.6.1 [istream.iterator]/1: +Requires: The resulting range shall not overlap with +either of the original ranges. The list will be sorted in +non-decreasing order according to the ordering defined by comp; +that is, for every iterator i in [first,last) other +than first, the condition *i < *(i - 1) or +comp(*i, *(i - 1)) will be false.

    -
    -istream_iterator reads (using operator>>) successive elements from the -input stream for which it was constructed. After it is constructed, and -every time ++ is used, the iterator reads and stores a value of T. If -the end of stream is reached the iterator fails to read and store a value of T -(operator void*() fail() on the stream returns -false true), the iterator becomes equal to the end-of-stream iterator value. -The constructor with no arguments istream_iterator() always constructs -an end of stream input iterator object, which is the only legitimate -iterator to be used for the end condition. The result of operator* on an -end of stream is not defined. For any other iterator value a const T& is -returned. The result of operator-> on an end of stream is not defined. -For any other iterator value a const T* is returned. It is impossible to -store things into istream iterators. The main peculiarity of the istream -iterators is the fact that ++ operators are not equality preserving, -that is, i == j does not guarantee at all that ++i == ++j. Every time ++ -is used a new value is read. -
    @@ -9507,7 +6869,7 @@ is used a new value is read.

    801. tuple and pair trivial members

    Section: 20.5 [tuple] Status: Open - Submitter: Lawrence Crowl Opened: 2008-02-18 Last modified: 2009-07-20

    + Submitter: Lawrence Crowl Opened: 2008-02-18 Last modified: 2009-10-23

    View all other issues in [tuple].

    View all issues with Open status.

    Discussion:

    @@ -9607,7 +6969,7 @@ tabled until Alisdair's proposals are disposed of.
    -This is partly solved by 1117. +This is partly solved by 1117.

    [ @@ -9650,6 +7012,15 @@ implied in the process (even if elided).

    +

    [ +2009-10 Santa Cruz: +]

    + + +
    +Leave as open. Alisdair to provide wording. +
    +

    Proposed resolution:

    @@ -9662,8 +7033,8 @@ implied in the process (even if elided).

    811. pair of pointers no longer works with literal 0

    -

    Section: 20.3.3 [pairs] Status: Open - Submitter: Doug Gregor Opened: 2008-03-14 Last modified: 2009-07-28

    +

    Section: 20.3.4 [pairs] Status: Open + Submitter: Doug Gregor Opened: 2008-03-14 Last modified: 2009-10-23

    View other active issues in [pairs].

    View all other issues in [pairs].

    View all issues with Open status.

    @@ -9724,6 +7095,15 @@ Related to 815. std::function and reference_closure do not use perfect forwarding -

    Section: 20.7.16.2.4 [func.wrap.func.inv] Status: Open - Submitter: Alisdair Meredith Opened: 2008-03-16 Last modified: 2009-07-16

    +

    Section: 20.7.15.2.4 [func.wrap.func.inv] Status: Open + Submitter: Alisdair Meredith Opened: 2008-03-16 Last modified: 2009-10-23

    View all issues with Open status.

    Discussion:

    @@ -9928,6 +7308,15 @@ Draft so that we know how to write the proposed resolution in terms of diffs to otherwise stable text.

    +

    [ +2009-10 Santa Cruz: +]

    + + +
    +Leave as open. Howard to provide wording. Howard welcomes any help. +
    +

    Proposed resolution:

    @@ -9940,11 +7329,11 @@ diffs to otherwise stable text.

    816. Should bind()'s returned functor have a nofail copy ctor when bind() is nofail?

    -

    Section: 20.7.12.1.3 [func.bind.bind] Status: Open - Submitter: Stephan T. Lavavej Opened: 2008-02-08 Last modified: 2009-07-16

    +

    Section: 20.7.11.1.3 [func.bind.bind] Status: Ready + Submitter: Stephan T. Lavavej Opened: 2008-02-08 Last modified: 2009-11-07

    View other active issues in [func.bind.bind].

    View all other issues in [func.bind.bind].

    -

    View all issues with Open status.

    +

    View all issues with Ready status.

    Discussion:

    Library Issue 527 notes that bind(f, t1, ..., tN) @@ -10010,11 +7399,20 @@ Move to Open, and likewise for issue 817 (see below). Leave Open. +

    [ +2009-10 Santa Cruz: +]

    + + +
    +Move to Ready. Decoupling from issue 817. +
    +

    Proposed resolution:

    -Add a new sentence to the end of paragraphs 2 and 4 of 20.7.12.1.3 [func.bind.bind]: +Add a new sentence to the end of paragraphs 2 and 4 of 20.7.11.1.3 [func.bind.bind]:

    @@ -10029,7 +7427,7 @@ in BoundArgs... throw an exception.

    ...

    --4- Returns: A forwarding call wrapper g with a nested type result_type defined as a synonym +-5- Returns: A forwarding call wrapper g with a nested type result_type defined as a synonym for R. The effect of g(u1, u2, ..., uM) shall be INVOKE(f, v1, v2, ..., vN, R), where the values and types of the bound arguments v1, v2, ..., vN are determined as specified below. The copy constructor and move constructor of the forwarding call wrapper shall throw an @@ -10045,8 +7443,8 @@ in BoundArgs... throw an exception.

    817. bind needs to be moved

    -

    Section: 20.7.12.1.3 [func.bind.bind] Status: Open - Submitter: Howard Hinnant Opened: 2008-03-17 Last modified: 2009-07-16

    +

    Section: 20.7.11.1.3 [func.bind.bind] Status: Open + Submitter: Howard Hinnant Opened: 2008-03-17 Last modified: 2009-11-08

    View other active issues in [func.bind.bind].

    View all other issues in [func.bind.bind].

    View all issues with Open status.

    @@ -10140,7 +7538,7 @@ a place to see the complete solution in one place. bind needs to be "moved".
  • -20.7.12.1.3 [func.bind.bind]/p3, p6 and p7 were accidently removed from N2798. +20.7.11.1.3 [func.bind.bind]/p3, p6 and p7 were accidently removed from N2798.
  • Issue 929 argues for a way to pass by && for @@ -10175,6 +7573,20 @@ and recommend both issues be considered together The proposed resolution uses concepts. Leave Open. +

    [ +2009-10 Santa Cruz: +]

    + + +
    +Leave as Open. Howard to provide deconceptified wording. +
    + +

    [ +2009-11-07 Howard updates wording. +]

    + +

    Proposed resolution:

    @@ -10182,92 +7594,173 @@ The proposed resolution uses concepts. Leave Open. Change 20.7 [function.objects] p2:

    -
    template<CopyConstructible MoveConstructible Fn, CopyConstructible MoveConstructible... Types>
-  unspecified bind(Fn&&, Types&&...);
-template<Returnable R, CopyConstructible MoveConstructible Fn, CopyConstructible MoveConstructible... Types>
-  unspecified bind(Fn&&, Types&&...);
+
    template<class Fn, class... Types BoundArgs>
+  unspecified bind(Fn&&, Types BoundArgs&&...);
+template<class R, class Fn, class... Types BoundArgs>
+  unspecified bind(Fn&&, Types BoundArgs&&...);
 
    
 
 
    
-Change 20.7.12.1.3 [func.bind.bind]:
+Change 20.7.11.1.3 [func.bind.bind]:
 
    
 
-
    template<CopyConstructible MoveConstructible F, CopyConstructible MoveConstructible... BoundArgs>
-  unspecified bind(F&& f, BoundArgs&&... bound_args);
-
    
-
 
    
-
    
-Requires: unspecified return type shall be MoveConstructible.
-
    
-
    
--1- Requires: INVOKE(f, w1, w2, ..., wN) (20.6.2) shall be a valid expression for some values
-w1, w2, ..., wN, where N == sizeof...(bound_args).
-
    
-
    
--2- Returns: A forwarding call wrapper g with a weak result type (20.6.2). The effect of g(u1, u2,
-..., uM) shall be INVOKE(f, v1, v2, ..., vN, Callable<F cv,V1, V2, ..., VN>::result_type), where cv
-represents the cv-qualifiers of g and the values and types of the bound arguments
-v1, v2, ..., vN are determined as specified below.
-
    
 
    
-Throws: Nothing unless the constructor of F or of one of the types in the BoundArgs... pack expansion
-throws an exception.
-
    
-
    
-
-
    template<Returnable R, CopyConstructible MoveConstructible F, CopyConstructible MoveConstructible... BoundArgs>
-  unspecified bind(F&& f, BoundArgs&&... bound_args);
-
    
-
-
    
-
    
-Requires: unspecified return type shall be MoveConstructible.
-
    
-
    
--3- Requires: INVOKE(f, w1, w2, ..., wN) shall be a valid expression for some values w1, w2, ...,
-wN, where N == sizeof...(bound_args).
-
    
-
    
--4- Returns: A forwarding call wrapper g with a nested type result_type defined as a synonym
-for R. The effect of g(u1, u2, ..., uM) shall be INVOKE(f, v1, v2, ..., vN, R), where the
-values and types of the bound arguments v1, v2, ..., vN are determined as specified below.
-
    
-
    
-
    
-Throws: Nothing unless the constructor of F or of one of the types in the BoundArgs... pack expansion
-throws an exception.
-
    
-
-
    
-
-
    
-Let the values of bound arguments v1, v2, ..., vN and
-their corresponding types V1, V2, ..., VN depend on the type of
-the corresponding argument ti in bound_args in the
-call to bind and the cv-qualifiers cv of the call
-wrapper g as follows. Let Ti be an alias for the ith
-element of the pack expansion decay<BoundArgs>::type...,
-and let ti be an alias for the ith element in the function
-parameter pack expansion bound_args...:
+Within this clause:
 
    
 
 
      
 
    • 
-if ti is of type reference_wrapper<T> the argument is
-ti.get() and its type Vi is T&;
+Let FD be a synonym for the type decay<F>::type.
 
      • 
 
    • 
-if the value of std::is_bind_expression<Ti>::value is true the argument is ti(u1, u2, ..., uM) and
-its type Vi is result_of<Ti cv (U1&, U2&, ..., UM&)>::type;
+Let fd be an lvalue of type FD constructed from
+std::forward<F>(f).
 
      • 
 
    • 
-if the value j of std::is_placeholder<Ti>::value is not zero the argument is std::forward<Uj>(uj) and
-its type Vi is Uj&&;
+Let Ti be a synonym for the ith type in the
+parameter pack BoundArgs.
 
      • 
 
    • 
-otherwise the value is ti and its type Vi is Ti cv &.
+Let TiD be a synonym for the type decay<Ti>::type.
 
      • 
+
    • 
+Let ti be the ith argument in bound_args.
+
      • 
+
    • 
+Let tid be an lvalue of type TiD constructed from
+std::forward<Ti>(ti).
+
      • 
+
    
+
+
    template<class F, class... BoundArgs>
+  unspecified bind(F&& f, BoundArgs&&... bound_args);
+
    
+
+
    
+
    
+-1- Requires:
+is_constructible<FD, F>::value
+shall be true.
+is_constructible<TiD, Ti>::value
+shall be true.
+F and each Ti in
+BoundArgs shall be CopyConstructible.
+INVOKE(fd, w1, w2, ..., wN) (20.7.2 [func.require]) shall be a valid expression for some values
+w1, w2, ..., wN, where N == sizeof...(bound_args).
+
    
+
    
+-2- Returns: A forwarding call wrapper g with a weak
+result type (20.7.2 [func.require]). The effect of g(u1, u2,
+..., uM) shall be INVOKE(fd, v1, v2, ..., vN,
+result_of<FD cv (V1, V2, ..., VN)>::type), where
+cv represents the cv-qualifiers of g and the
+values and types of the bound arguments v1, v2, ..., vN are
+determined as specified below.
+The copy constructor and move constructor of the forwarding call wrapper shall throw an
+exception if and only if the corresponding constructor of FD or any of the types
+TiD throw an exception.
+
    
+
    
+-3- Throws: Nothing unless the copy
+constructionor of
+Ffd or of one of the values
+tid types in the BoundArgs... pack
+expansion throws an exception.
+
    
+
    
+
+Remarks: The unspecified return type shall be
+MoveConstructible.  If all of FD and TiD are
+CopyConstructible then the unspecified return type shall
+be CopyConstructible. [Note: This implies that all of
+FD and TiD shall be MoveConstructible —
+end note]
+
+
    
+
    
+
+
    template<class R, class F, class... BoundArgs>
+  unspecified bind(F&& f, BoundArgs&&... bound_args);
+
    
+
+
    
+
    
+-4- Requires:
+is_constructible<FD, F>::value
+shall be true.
+is_constructible<TiD, Ti>::value
+shall be true.
+F and each Ti in
+BoundArgs shall be CopyConstructible.
+INVOKE(fd, w1,
+w2, ..., wN) shall be a valid expression for some values w1, w2,
+..., wN, where N == sizeof...(bound_args).
+
    
+
    
+-5- Returns: A forwarding call wrapper g with a nested
+type result_type defined as a synonym for R. The
+effect of g(u1, u2, ..., uM) shall be INVOKE(fd, v1,
+v2, ..., vN, R), where the values and types of the bound arguments
+v1, v2, ..., vN are determined as specified below.
+The copy constructor and move constructor of the forwarding call wrapper shall throw an
+exception if and only if the corresponding constructor of FD or any of the types
+TiD throw an exception.
+
    
+
    
+-6- Throws: Nothing unless the copy
+constructionor of
+Ffd or of one of the values
+tid types in the BoundArgs... pack
+expansion throws an exception.
+
    
+
    
+
+Remarks: The unspecified return type shall be
+MoveConstructible.  If all of FD and TiD are
+CopyConstructible then the unspecified return type shall
+be CopyConstructible. [Note: This implies that all of
+FD and TiD shall be MoveConstructible —
+end note]
+
+
    
+
    
+
+
    
+-7- The values of the bound arguments v1, v2, ..., vN and
+their corresponding types V1, V2, ..., VN depend on the types
+TiD derived from
+of the corresponding argument ti in bound_args of type
+Ti in BoundArgs in
+the call to bind and the
+cv-qualifiers cv of the call wrapper g as
+follows:
+
    
+
+
      
+
    • 
+if ti TiD is of has
+type reference_wrapper<T> the argument is
+tid.get() and its type Vi is
+T&;
+
      • 
+
    • 
+if the value of
+std::is_bind_expression<TiD>::value is
+true the argument is tid(u1, u2, ..., uM)
+and its type Vi is result_of<TiD cv
+(U1&, U2&, ..., UM&)>::type;
+
      • 
+
    • 
+if the value j of
+std::is_placeholder<TiD>::value is not zero
+the argument is std::forward<Uj>(uj) and its type
+Vi is Uj&&;
+
      • 
+
    • 
+otherwise the value is tid and its type Vi
+is TiD cv &.
+
      • 
 
    
 
 
    
@@ -10280,7 +7773,7 @@ otherwise the value is ti and its type Vi is Ti cv &
 
    819. rethrow_if_nested
    
 
    Section: 18.8.6 [except.nested] Status: Open
- Submitter: Alisdair Meredith Opened: 2008-03-25  Last modified: 2008-09-17
    
+ Submitter: Alisdair Meredith Opened: 2008-03-25  Last modified: 2009-10-23
    
 
    View other active issues in [except.nested].
    
 
    View all other issues in [except.nested].
    
 
    View all issues with Open status.
    
@@ -10321,470 +7814,18 @@ San Francisco:
 Alisdair was volunteered to provide wording.
    - -

    Proposed resolution:

    - - - - - -
    -

    822. Object with explicit copy constructor no longer CopyConstructible

    -

    Section: X [utility.arg.requirements] Status: Ready - Submitter: James Kanze Opened: 2008-04-01 Last modified: 2009-07-26

    -

    View other active issues in [utility.arg.requirements].

    -

    View all other issues in [utility.arg.requirements].

    -

    View all issues with Ready status.

    -

    Discussion:

    -

    -I just noticed that the following program is legal in C++03, but -is forbidden in the current draft: -

    - -
    #include <vector>
-#include <iostream>
-
-class Toto
-{
-public:
-    Toto() {}
-    explicit Toto( Toto const& ) {}
-} ;
-
-int
-main()
-{
-    std::vector< Toto > v( 10 ) ;
-    return 0 ;
-}
-
    - -

    -Is this change intentional? (And if so, what is the -justification? I wouldn't call such code good, but I don't see -any reason to break it unless we get something else in return.) -

    -

    [ -San Francisco: +2009-10 Santa Cruz: ]

    -The subgroup that looked at this felt this was a good change, but it may -already be handled by incoming concepts (we're not sure). -
    - -

    [ -Post Summit: -]

    - - -
    -

    -Alisdair: Proposed resolution kinda funky as these tables no longer -exist. Move from direct init to copy init. Clarify with Doug, recommends -NAD. -

    -

    -Walter: Suggest NAD via introduction of concepts. -

    -

    -Recommend close as NAD. -

    -
    - -

    [ -2009-07 Frankfurt: -]

    - - -
    -Need to look at again without concepts. -
    - -

    [ -2009-07 Frankfurt: -]

    - - -
    -

    -Move to Ready with original proposed resolution. -

    -

    [Howard: Original proposed resolution restored.]

    - +Leave as Open. Alisdair to provide wording.

    Proposed resolution:

    -

    -In X [utility.arg.requirements] change Table 33: MoveConstructible requirements [moveconstructible]: -

    - -
    - - - - - - - - - - -
    expressionpost-condition
    T t(rv) = rvt is equivalent to the value of rv before the construction
    ...
    -
    - -

    -In X [utility.arg.requirements] change Table 34: CopyConstructible requirements [copyconstructible]: -

    - -
    - - - - - - - - - - -
    expressionpost-condition
    T t(u) = uthe value of u is unchanged and is equivalent to t
    ...
    -
    - - - - - -
    -

    823. identity<void> seems broken

    -

    Section: 20.3.2 [forward] Status: Open - Submitter: Walter Brown Opened: 2008-04-09 Last modified: 2009-07-30

    -

    View other active issues in [forward].

    -

    View all other issues in [forward].

    -

    View all issues with Open status.

    -

    Discussion:

    -

    -N2588 seems to have added an operator() member function to the -identity<> helper in 20.3.2 [forward]. I believe this change makes it no -longer possible to instantiate identity<void>, as it would require -forming a reference-to-void type as this operator()'s parameter type. -

    - -

    -Suggested resolution: Specialize identity<void> so as not to require -the member function's presence. -

    - -

    [ -Sophia Antipolis: -]

    - - -
    -

    -Jens: suggests to add a requires clause to avoid specializing on void. -

    -

    -Alisdair: also consider cv-qualified void. -

    -

    -Alberto provided proposed wording. -

    -
    - -

    [ -2009-07-30 Daniel reopens: -]

    - - -
    -

    -This issue became closed, because the ReferentType requirement -fixed the problem - this is no longer the case. In retrospective it seems -to be that the root of current issues around std::identity (823, 700, -939) -is that it was standardized as something very different (an unconditional -type mapper) than traditional usage indicated (a function object that should -derive from std::unary_function), as the SGI definition does. This issue could -be solved, if std::identity is removed (one proposal of 939), but until this -has been decided, this issue should remain open. An alternative for -removing it, would be, to do the following: -

    - -
      -
    1. -

      -Let identity stay as a real function object, which would -now properly -derive from unary_function: -

      - -
      template <class T> struct identity : unary_function<T, T> {
-  const T& operator()(const T&) const;
-};
-
      -
      2. - -
    2. -

      -Invent (if needed) a generic type wrapper (corresponding to concept -IdentityOf), -e.g. identity_of, and move it's prototype description back to 20.3.2 [forward]: -

      - -
      template <class T> struct identity_of {
-  typedef T type;
-};
-
      - -

      -and adapt the std::forward signature to use identity_of -instead of identity. -

      -
      3. -
    -
    - - -

    Proposed resolution:

    -

    -Change definition of identity in 20.3.2 [forward], paragraph 2, to: -

    - -
    template <class T>  struct identity {
-    typedef T type;
-
-    requires ReferentType<T>
-      const T& operator()(const T& x) const;
-  };
-
    -

    ...

    -
      requires ReferentType<T>
-    const T& operator()(const T& x) const;
-
    - - -

    Rationale:

    -

    -The point here is to able to write T& given T and ReferentType is -precisely the concept that guarantees so, according to N2677 -(Foundational concepts). Because of this, it seems preferable than an -explicit check for cv void using SameType/remove_cv as it was suggested -in Sophia. In particular, Daniel remarked that there may be types other -than cv void which aren't referent types (int[], perhaps?). -

    - - - - - -
    -

    827. constexpr shared_ptr::shared_ptr()?

    -

    Section: 20.8.10.2.1 [util.smartptr.shared.const] Status: Open - Submitter: Peter Dimov Opened: 2008-04-11 Last modified: 2009-07-21

    -

    View other active issues in [util.smartptr.shared.const].

    -

    View all other issues in [util.smartptr.shared.const].

    -

    View all issues with Open status.

    -

    Discussion:

    -

    -Would anyone object to making the default constructor of shared_ptr (and -weak_ptr and enable_shared_from_this) constexpr? This would enable -static initialization for shared_ptr variables, eliminating another -unfair advantage of raw pointers. -

    - -

    [ -San Francisco: -]

    - - -
    -

    -It's not clear to us that you can initialize a pointer with the literal -0 in a constant expression. We need to ask CWG to make sure this works. -Bjarne has been appointed to do this. -

    -

    -Core got back to us and assured as that nullptr would do the job -nicely here. -

    -
    - -

    [ -2009-05-01 Alisdair adds: -]

    - - -
    -

    -I don't believe that constexpr will buy anything in this case. -shared_ptr/weak_ptr/enable_shared_from_this cannot be literal types as they -have a non-trivial copy constructor. As they do not produce literal types, -then the constexpr default constructor will not guarantee constant -initialization, and so not buy the hoped for optimization. -

    -

    -I recommend referring this back to Core to see if we can get static -initialization for types with constexpr constructors, even if they are not -literal types. Otherwise this should be closed as NAD. -

    -
    - -

    [ -2009-05-26 Daniel adds: -]

    - - -
    -If Alisdair's 2009-05-01 comment is correct, wouldn't that also make -constexpr mutex() useless, because this class has a non-trivial -destructor? (828) -
    - -

    [ -2009-07-21 Alisdair adds: -]

    - - -
    -

    -The feedback from core is that this and similar uses of constexpr -constructors to force static initialization should be supported. If -there are any problems with this in the working draught, we should file -core issues. -

    - -

    -Recommend we declare the default constructor constexpr as the issue suggests -(proposed wording added). -

    -
    - - - -

    Proposed resolution:

    -

    -Change 20.8.10.2 [util.smartptr.shared] and 20.8.10.2.1 [util.smartptr.shared.const]: -

    - -
    consexpr shared_ptr();
-
    - -

    -Change 20.8.10.3 [util.smartptr.weak] and 20.8.10.3.1 [util.smartptr.weak.const]: -

    - -
    consexpr weak_ptr();
-
    - -

    -Change 20.8.10.5 [util.smartptr.enab] (2 places): -

    - -
    consexpr enable_shared_from_this();
-
    - - - - - - -
    -

    828. Static initialization for std::mutex?

    -

    Section: 30.4.1.1 [thread.mutex.class] Status: Review - Submitter: Peter Dimov Opened: 2008-04-18 Last modified: 2009-05-30

    -

    View other active issues in [thread.mutex.class].

    -

    View all other issues in [thread.mutex.class].

    -

    View all issues with Review status.

    -

    Discussion:

    -

    -[Note: I'm assuming here that 3.6.2 [basic.start.init]/1 will be fixed.] -

    -

    -Currently std::mutex doesn't support static initialization. This is a -regression with respect to pthread_mutex_t, which does. I believe that -we should strive to eliminate such regressions in expressive power where -possible, both to ease migration and to not provide incentives to (or -force) people to forego the C++ primitives in favor of pthreads. -

    - -

    [ -Sophia Antipolis: -]

    - - -
    -

    -We believe this is implementable on POSIX, because the initializer-list -feature and the constexpr feature make this work. Double-check core -language about static initialization for this case. Ask core for a core -issue about order of destruction of statically-initialized objects wrt. -dynamically-initialized objects (should come afterwards). Check -non-POSIX systems for implementability. -

    -

    -If ubiquitous implementability cannot be assured, plan B is to introduce -another constructor, make this constexpr, which is -conditionally-supported. To avoid ambiguities, this new constructor needs -to have an additional parameter. -

    -
    - -

    [ -Post Summit: -]

    - - -
    -

    -Jens: constant initialization seems to be ok core-language wise -

    -

    -Consensus: Defer to threading experts, in particular a Microsoft platform expert. -

    -

    -Lawrence to send e-mail to Herb Sutter, Jonathan Caves, Anthony Wiliams, -Paul McKenney, Martin Tasker, Hans Boehm, Bill Plauger, Pete Becker, -Peter Dimov to alert them of this issue. -

    -

    -Lawrence: What about header file shared with C? The initialization -syntax is different in C and C++. -

    -

    -Recommend Keep in Review -

    -
    - -

    [ -Batavia (2009-05): -]

    - -
    -Keep in Review status pending feedback from members of the Concurrency subgroup. -
    - -

    [ -See related comments from Alisdiar and Daniel in 827. -]

    - - - - -

    Proposed resolution:

    -

    -Change 30.4.1.1 [thread.mutex.class]: -

    - -
    class mutex {
-public:
-  constexpr mutex();
-  ...
-
    @@ -10792,11 +7833,11 @@ public:

    834. Unique_ptr::pointer requirements underspecified

    -

    Section: 20.8.9.2 [unique.ptr.single] Status: Ready - Submitter: Daniel Krügler Opened: 2008-05-14 Last modified: 2009-07-16

    +

    Section: 20.8.14.2 [unique.ptr.single] Status: Open + Submitter: Daniel Krügler Opened: 2008-05-14 Last modified: 2009-10-26

    View other active issues in [unique.ptr.single].

    View all other issues in [unique.ptr.single].

    -

    View all issues with Ready status.

    +

    View all issues with Open status.

    Discussion:

    Issue 673 (including recent updates by 821) proposes a useful @@ -10855,12 +7896,67 @@ Howard will go through and enumerate the individual requirements wrt. pointe Move to Ready. +

    [ +2009-10-15 Alisdair pulls from Ready: +]

    + + +
    +

    +I hate to pull an issue out of Ready status, but I don't think 834 is +fully baked yet. +

    + +

    +For reference the proposed resolution is to add the following words: +

    + +
    +unique_ptr<T, D>::pointer's operations shall be +well-formed, shall have well defined behavior, and shall not throw +exceptions. +
    + +

    +This leaves me with a big question : which operations? +

    + +

    +Are all pointer operations required to be nothrow, including operations +that have nothing to do with interactions with unique_ptr? This was +much simpler with concepts where we could point to operations within a +certain concept, and so nail down the interactions. +

    +
    + +

    [ +2009-10-15 Daniel adds: +]

    + + +
    +I volunteer to prepare a more fine-grained solution, but I would like +to ask for feedback that helps me doing so. If this question is asked +early in the meeting I might be able to fix it within the week, but I +cannot promise that now. +
    + +

    [ +2009-10 Santa Cruz: +]

    + + +
    +Leave in open. Daniel to provide wording as already suggested. +
    + +

    Proposed resolution:

    Add the following sentence just at the end of the newly proposed -20.8.9.2 [unique.ptr.single]/p. 3: +20.8.14.2 [unique.ptr.single]/p. 3:

    @@ -10874,11 +7970,11 @@ defined behavior, and shall not throw exceptions.

    835. tying two streams together (correction to DR 581)

    -

    Section: 27.5.4.2 [basic.ios.members] Status: Review - Submitter: Martin Sebor Opened: 2008-05-17 Last modified: 2009-07-27

    +

    Section: 27.5.4.2 [basic.ios.members] Status: Open + Submitter: Martin Sebor Opened: 2008-05-17 Last modified: 2009-10-20

    View other active issues in [basic.ios.members].

    View all other issues in [basic.ios.members].

    -

    View all issues with Review status.

    +

    View all issues with Open status.

    Discussion:

    @@ -10992,12 +8088,32 @@ Move back to Open. ]

    +

    [ +2009-10-13 Daniel adds: +]

    + + +
    +This proposed wording is written to match the outcome +of 397. +
    + +

    [ +2009 Santa Cruz: +]

    + + +
    +Move to Open. Martin to propose updated wording that will also resolve +issue 397 consistently. +
    +

    Proposed resolution:

    [ based on -N2914 +N2960 numbering ]

    @@ -11040,11 +8156,10 @@ os.good())     is true, calls os.flush() effects of money_base::space and money_base::none on money_get -

    Section: 22.4.6.1.2 [locale.money.get.virtuals] Status: Review - Submitter: Martin Sebor Opened: 2008-05-17 Last modified: 2009-07-16

    -

    View other active issues in [locale.money.get.virtuals].

    +

    Section: 22.4.6.1.2 [locale.money.get.virtuals] Status: Ready + Submitter: Martin Sebor Opened: 2008-05-17 Last modified: 2009-10-21

    View all other issues in [locale.money.get.virtuals].

    -

    View all issues with Review status.

    +

    View all issues with Ready status.

    Duplicate of: 670

    Discussion:

    @@ -11120,6 +8235,20 @@ In either case, any required MISSINGWORD followed by all optional whitespace (as

    Strike this sentence and move to Review.

    + +

    [ +Howard: done. +]

    + +
    + +

    [ +2009-10 Santa Cruz: +]

    + + +
    +Move to Ready.
    @@ -11152,650 +8281,11 @@ If (str.flags() & str.showbase) is false, ... -
    -

    838. - can an end-of-stream iterator become a non-end-of-stream one? -

    -

    Section: 24.6.1 [istream.iterator] Status: Ready - Submitter: Martin Sebor Opened: 2008-05-17 Last modified: 2009-07-16

    -

    View other active issues in [istream.iterator].

    -

    View all other issues in [istream.iterator].

    -

    View all issues with Ready status.

    -

    Discussion:

    -

    - -From message c++std-lib-20003... - -

    -

    - -The description of istream_iterator in -24.6.1 [istream.iterator], p1 specifies that objects of the -class become the end-of-stream (EOS) iterators under the -following condition (see also issue 788 another problem -with this paragraph): - -

    -
    - -If the end of stream is reached (operator void*() on the -stream returns false), the iterator becomes equal to -the end-of-stream iterator value. - -
    -

    - -One possible implementation approach that has been used in practice is -for the iterator to set its in_stream pointer to 0 when -it reaches the end of the stream, just like the default ctor does on -initialization. The problem with this approach is that -the Effects clause for operator++() says the -iterator unconditionally extracts the next value from the stream by -evaluating *in_stream >> value, without checking -for (in_stream == 0). - -

    -

    - -Conformance to the requirement outlined in the Effects clause -can easily be verified in programs by setting eofbit -or failbit in exceptions() of the associated -stream and attempting to iterate past the end of the stream: each -past-the-end access should trigger an exception. This suggests that -some other, more elaborate technique might be intended. - -

    -

    - -Another approach, one that allows operator++() to attempt -to extract the value even for EOS iterators (just as long -as in_stream is non-0) is for the iterator to maintain a -flag indicating whether it has reached the end of the stream. This -technique would satisfy the presumed requirement implied by -the Effects clause mentioned above, but it isn't supported by -the exposition-only members of the class (no such flag is shown). This -approach is also found in existing practice. - -

    -

    - -The inconsistency between existing implementations raises the question -of whether the intent of the specification is that a non-EOS iterator -that has reached the EOS become a non-EOS one again after the -stream's eofbit flag has been cleared? That is, are the -assertions in the program below expected to pass? - -

    -
    - 
       sstream strm ("1 ");
-   istream_iterator eos;
-   istream_iterator it (strm);
-   int i;
-   i = *it++
-   assert (it == eos);
-   strm.clear ();
-   strm << "2 3 ";
-   assert (it != eos);
-   i = *++it;
-   assert (3 == i);
-
    -
    -

    - -Or is it intended that once an iterator becomes EOS it stays EOS until -the end of its lifetime? - -

    - -

    [ -San Francisco: -]

    - - -
    -

    -We like the direction of the proposed resolution. We're not sure about -the wording, and we need more time to reflect on it, -

    -

    -Move to Open. Detlef to rewrite the proposed resolution in such a way -that no reference is made to exposition only members of -istream_iterator. -

    -
    - -

    [ -2009-07 Frankfurt: -]

    - - -
    -Move to Ready. -
    - - - -

    Proposed resolution:

    -

    - -The discussion of this issue on the reflector suggests that the intent -of the standard is for an istreambuf_iterator that has -reached the EOS to remain in the EOS state until the end of its -lifetime. Implementations that permit EOS iterators to return to a -non-EOS state may only do so as an extension, and only as a result of -calling istream_iterator member functions on EOS -iterators whose behavior is in this case undefined. - -

    -

    - -To this end we propose to change 24.6.1 [istream.iterator], p1, -as follows: - -

    -
    - -The result of operator-> on an end-of-stream -is not defined. For any other iterator value a const T* -is returned. Invoking operator++() on -an end-of-stream iterator is undefined. It is impossible -to store things into istream iterators... - -
    -

    - -Add pre/postconditions to the member function descriptions of istream_iterator like so: - -

    -
    - -
    istream_iterator();
    - -Effects: Constructs the end-of-stream iterator.
    -Postcondition: in_stream == 0. - -
    istream_iterator(istream_type &s);
    - -Effects: Initializes in_stream with &s. value -may be initialized during construction or the first time it is -referenced.
    -Postcondition: in_stream == &s. - -
    istream_iterator(const istream_iterator &x);
    - -Effects: Constructs a copy of x.
    -Postcondition: in_stream == x.in_stream. - -
    istream_iterator& operator++();
    - -Requires: in_stream != 0.
    -Effects: *in_stream >> value. - -
    istream_iterator& operator++(int);
    - -Requires: in_stream != 0.
    -Effects: - 
    istream_iterator tmp (*this);
-*in_stream >> value;
-return tmp;
-
    -
    -
    - - - - -
    -

    847. string exception safety guarantees

    -

    Section: 21.4.1 [string.require] Status: Ready - Submitter: Hervé Brönnimann Opened: 2008-06-05 Last modified: 2009-07-16

    -

    View all other issues in [string.require].

    -

    View all issues with Ready status.

    -

    Discussion:

    -

    -In March, on comp.lang.c++.moderated, I asked what were the -string exception safety guarantees are, because I cannot see -*any* in the working paper, and any implementation I know offers -the strong exception safety guarantee (string unchanged if a -member throws exception). The closest the current draft comes to -offering any guarantees is 21.4 [basic.string], para 3: -

    - -
    -The class template basic_string conforms to the requirements -for a Sequence Container (23.1.1), for a Reversible Container (23.1), -and for an Allocator-aware container (91). The iterators supported by -basic_string are random access iterators (24.1.5). -
    - -

    -However, the chapter 23 only says, on the topic of exceptions: 23.2 [container.requirements], -para 10: -

    - -
    -

    -Unless otherwise specified (see 23.2.2.3 and 23.2.6.4) all container types defined in this clause meet the following -additional requirements: -

    - -
      -
    • if an exception is thrown by...
      • -
    -
    - -

    -I take it as saying that this paragraph has *no* implication on -std::basic_string, as basic_string isn't defined in Clause 23 and -this paragraph does not define a *requirement* of Sequence -nor Reversible Container, just of the models defined in Clause 23. -In addition, LWG Issue 718 proposes to remove 23.2 [container.requirements], para 3. -

    - -

    -Finally, the fact that no operation on Traits should throw -exceptions has no bearing, except to suggest (since the only -other throws should be allocation, out_of_range, or length_error) -that the strong exception guarantee can be achieved. -

    - -

    -The reaction in that group by Niels Dekker, Martin Sebor, and -Bo Persson, was all that this would be worth an LWG issue. -

    - -

    -A related issue is that erase() does not throw. This should be -stated somewhere (and again, I don't think that the 23.2 [container.requirements], para 1 -applies here). -

    - -

    [ -San Francisco: -]

    - - -
    -Implementors will study this to confirm that it is actually possible. -
    - -

    [ -Daniel adds 2009-02-14: -]

    - - -
    -The proposed resolution of paper -N2815 -interacts with this issue (the paper does not refer to this issue). -
    - -

    [ -2009-07 Frankfurt: -]

    - - -
    -Move to Ready. -
    - - - -

    Proposed resolution:

    -

    -Add a blanket statement in 21.4.1 [string.require]: -

    - -
    -

    -- if any member function or operator of basic_string<charT, traits, Allocator> -throws, that function or operator has no effect. -

    -

    -- no erase() or pop_back() function throws. -

    -
    - -

    -As far as I can tell, this is achieved by any implementation. If I made a -mistake and it is not possible to offer this guarantee, then -either state all the functions for which this is possible -(certainly at least operator+=, append, assign, and insert), -or add paragraphs to Effects clauses wherever appropriate. -

    - - - - - -
    -

    851. simplified array construction

    -

    Section: 23.3.1 [array] Status: Open - Submitter: Benjamin Kosnik Opened: 2008-06-05 Last modified: 2009-07-25

    -

    View other active issues in [array].

    -

    View all other issues in [array].

    -

    View all issues with Open status.

    -

    Discussion:

    -

    -This is an issue that came up on the libstdc++ list, where a -discrepancy between "C" arrays and C++0x's std::array was pointed -out. -

    - -

    -In "C," this array usage is possible: -

    - -
    int ar[] = {1, 4, 6};
-
    - -

    -But for C++, -

    - -
    std::array<int> a = { 1, 4, 6 }; // error
-
    - -

    -Instead, the second parameter of the array template must be -explicit, like so: -

    - -
    std::array<int, 3> a = { 1, 4, 6 };
-
    - -

    -Doug Gregor proposes the following solution, that assumes -generalized initializer lists. -

    - -
    template<typename T, typename... Args>
-inline array<T, sizeof...(Args)> 
-make_array(Args&&... args) 
-{ return { std::forward<Args>(args)... };  }
-
    - -

    -Then, the way to build an array from a list of unknown size is: -

    - -
    auto a = make_array<T>(1, 4, 6);
-
    - -

    [ -San Francisco: -]

    - - -
    -

    -Benjamin: Move to Ready? -

    -

    -Bjarne: I'm not convinced this is useful enough to add, so I'd like us -to have time to reflect on it. -

    -

    -Alisdair: the constraints are wrong, they should be -

    -
    template<ValueType T, ValueType... Args>
-requires Convertible<Args, T>...
-array<T, sizeof...(Args)> make_array(Args&&... args);
-
    -

    -Alidair: this would be useful if we had a constexpr version. -

    -

    -Bjarne: this is probably useful for arrays with a small number of -elements, but it's not clearly useful otherwise. -

    -

    -Consensus is to move to Open. -

    -
    - -

    [ -2009-06-07 Daniel adds: -]

    - - -
    -

    -I suggest a fix and a simplification of the current proposal: Recent -prototyping by -Howard showed, that a fix is required because narrowing conversion -8.5.4 [dcl.init.list]/6 b.3 -would severely limit the possible distribution of argument types, e.g. -the expression -make_array<double>(1, 2.0) is ill-formed, because the narrowing -happens inside the -function body where no constant expressions exist anymore. Furthermore -given e.g. -

    -
    int f();
-double g();
-
    -

    -we probably want to support -

    -
    make_array<double>(f(), g());
-
    - -

    -as well. To make this feasible, the currently suggested expansion -

    - -
    { std::forward<Args>(args)... }
-
    - -

    -needs to be replaced by -

    - -
    { static_cast<T>(std::forward<Args>(args))... }
-
    - -

    -which is safe, because we already ensure convertibility via the -element-wise Convertible<Args, T> requirement. Some other fixes are -necessary: The ValueType requirement for the function parameters -is invalid, because all lvalue arguments will deduce to an lvalue-reference, -thereby no longer satisfying this requirement. -

    - -

    -The suggested simplification is to provide a default-computed effective -type for the result array based on common_type and decay, in -unconstrained form: -

    - -
    template<typename... Args>
-array<typename decay<typename common_type<Args...>::type>::type,
-sizeof...(Args)>
-make_array(Args&&... args);
-
    - -

    -The approach used below is similar to that of make_pair and make_tuple -using a symbol C to represent the decayed common type [Note: Special -handling of reference_wrapper types is intentionally not provided, because -our target has so satisfy ValueType, thus under the revised proposal only -an all-reference_wrapper-arguments would be well-formed and an array of -reference_wrapper will be constructed]. I do currently not suggest to -add new concepts reflecting decay and common_type, but an implementor will -need something like this to succeed. Note that we use a similar fuzziness for -make_pair and make_tuple currently. This fuzziness is not related to -the currently -missing Constructible<Vi, Ti&&> requirement for those functions. The following -proposal fixes that miss for make_array. If the corresponding C type -deduction is -explicitly wanted for standardization, here the implementation -

    - -
    auto concept DC<typename... T> {
-  typename type = typename decay<typename common_type<T...>::type>::type;
-}
-
    - -

    -where C is identical to DC<Args...>::type in the proposed resolution below. -

    -

    -I intentionally added no further type relation between type and the concept -template parameters, but instead added this requirement below to make -the specification as transparent as possible. As written this concept is -satisfied, if the corresponding associated type exists. -

    - -

    Suggested Resolution:

    - -
      -
    1. -

      -Add to the array synopsis in 23.3 [sequences]: -

      -
      
-template<ReferentType... Args>
-requires ValueType<C> && IdentityOf<Args> && Constructible<C, Args&&>...
-array<C, sizeof...(Args)>
-make_array(Args&&... args);
-
-
      -
      2. - -
    2. -

      -Append after 23.3.1.7 [array.tuple] Tuple interface to class template array -the following new section: -

      -
      -

      -23.4.1.7 Array creation functions [array.creation] -

      - -
      
-template<ReferentType... Args>
-requires ValueType<C> && IdentityOf<Args> && Constructible<C, Args&&>...
-array<C, sizeof...(Args)>
-make_array(Args&&... args);
-
      - -
      -

      -Let C be decay<common_type<Args...>::type>::type. -

      -

      -Returns: an array<C, sizeof...(Args)> initialized with -{ static_cast<C>(std::forward<Args>(args))... }. -

      -
      -
      - -
      3. - -
    - -
    - -

    [ -2009-07 Frankfurt: -]

    - - -
    -

    -The proposed resolution uses concepts. -

    -

    -Daniel to rewrite the proposed resolution. -

    -

    -Leave Open. -

    -
    - -

    [ -2009-07-25 Daniel provides rewritten proposed resolution. -]

    - - - - -

    Proposed resolution:

    - -
      -
    1. -

      -Add to the array synopsis in 23.3 [sequences]: -

      - -
      template<class... Args>
-  array<CT, sizeof...(Args)>
-  make_array(Args&&... args);
-
      -
      2. - -
    2. -

      -Append after 23.3.1.7 [array.tuple] "Tuple interface to class template array" the -following new section: -

      - -
      -

      -XX.X.X.X Array creation functions [array.creation] -

      - -
      
-template<class... Args>
-array<CT, sizeof...(Args)>
-make_array(Args&&... args)
-
      - -
      -

      -Let CT be decay<common_type<Args...>::type>::type. -

      -

      -Returns: An array<CT, sizeof...(Args)> initialized with { -static_cast<CT>(std::forward<Args>(args))... }. -

      - -

      -[Example: -

      -
      
-int i = 0; int& ri = i;
-make_array(42u, i, 2.78, ri);
-
      -

      -returns an array of type -

      -
      
-array<double, 4>
-
      - -

      -—end example] -

      -
      -
      -
      3. - -
    - - - - - - - -

    854. default_delete converting constructor underspecified

    -

    Section: 20.8.9.1.1 [unique.ptr.dltr.dflt] Status: Review - Submitter: Howard Hinnant Opened: 2008-06-18 Last modified: 2009-07-26

    -

    View all issues with Review status.

    +

    Section: 20.8.14.1.1 [unique.ptr.dltr.dflt] Status: Ready + Submitter: Howard Hinnant Opened: 2008-06-18 Last modified: 2009-10-21

    +

    View all issues with Ready status.

    Discussion:

    No relationship between U and T in the converting constructor for default_delete template. @@ -11888,10 +8378,20 @@ Move back to Open. ]

    +

    [ +2009-10 Santa Cruz: +]

    + + +
    +Move to Ready. +
    + +

    Proposed resolution:

    -Add after 20.8.9.1.1 [unique.ptr.dltr.dflt], p1: +Add after 20.8.14.1.1 [unique.ptr.dltr.dflt], p1: 

    template <class U> default_delete(const default_delete<U>& other);
@@ -11912,843 +8412,12 @@ if and only if U* is implicitly convertible to T*.
 
 
 
-
    
-
    857. condition_variable::time_wait return bool error prone
    
-
    Section: 30.5.1 [thread.condition.condvar] Status: Ready
- Submitter: Beman Dawes Opened: 2008-06-13  Last modified: 2009-07-16
    
-
    View other active issues in [thread.condition.condvar].
    
-
    View all other issues in [thread.condition.condvar].
    
-
    View all issues with Ready status.
    
-
    Discussion:
    
-
    
-The meaning of the bool returned by condition_variable::timed_wait is so
-obscure that even the class' designer can't deduce it correctly. Several
-people have independently stumbled on this issue.
-
    
-
    
-It might be simpler to change the return type to a scoped enum:
-
    
-
    enum class timeout { not_reached, reached };
-
    
-
-
    
-That's the same cost as returning a bool, but not subject to mistakes. Your example below would be:
-
    
-
-
    if (cv.wait_until(lk, time_limit) == timeout::reached )
-  throw time_out();
-
    
-
-
    [
-Beman to supply exact wording.
-]
    
-
-
-
    [
-San Francisco:
-]
    
-
-
-
    
-
    
-There is concern that the enumeration names are just as confusing, if
-not more so, as the bool. You might have awoken because of a signal or a
-spurious wakeup, for example.
-
    
-
    
-Group feels that this is a defect that needs fixing.
-
    
-
    
-Group prefers returning an enum over a void return.
-
    
-
    
-Howard to provide wording.
-
    
-
    
-
-
    [
-2009-06-14 Beman provided wording.
-]
    
-
-
-
    [
-2009-07 Frankfurt:
-]
    
-
-
-
    
-Move to Ready.
-
    
-
-
-
-
    Proposed resolution:
    
-
    
-Change Condition variables 30.5 [thread.condition], Header
-condition_variable synopsis, as indicated:
-
    
-
-
    namespace std {
-  class condition_variable;
-  class condition_variable_any;
-
-  enum class cv_status { no_timeout, timeout };
-}
-
    
-
-
    
-Change Class condition_variable 30.5.1 [thread.condition.condvar] as indicated:
-
    
-
-
    class condition_variable { 
-public:
-  ...
-  template <class Clock, class Duration>
-    bool cv_status wait_until(unique_lock<mutex>& lock,
-                    const chrono::time_point<Clock, Duration>& abs_time);
-  template <class Clock, class Duration, class Predicate>
-    bool wait_until(unique_lock<mutex>& lock,
-                    const chrono::time_point<Clock, Duration>& abs_time,
-                    Predicate pred);
-
-  template <class Rep, class Period>
-    bool cv_status wait_for(unique_lock<mutex>& lock,
-                  const chrono::duration<Rep, Period>& rel_time);
-  template <class Rep, class Period, class Predicate>
-    bool wait_for(unique_lock<mutex>& lock,
-                  const chrono::duration<Rep, Period>& rel_time,
-                  Predicate pred);
-  ...
-};
-
-...
-
-template <class Clock, class Duration>
-  bool cv_status wait_until(unique_lock<mutex>& lock,
-                  const chrono::time_point<Clock, Duration>& abs_time);
-
    
-
    
-
    
--15- Precondition: lock is locked by the calling thread, and either
-
    
-
      
-
    • 
-no other thread is waiting on this condition_variable object or
-
      • 
-
    • 
-lock.mutex() returns the same value for each of the lock
-arguments supplied by all concurrently waiting threads (via wait,
-wait_for or wait_until.).
-
      • 
-
    
-
-
    
--16- Effects:
-
    
-
-
      
-
    • 
-Atomically calls lock.unlock() and blocks on *this.
-
      • 
-
    • 
-When unblocked, calls lock.lock() (possibly blocking on the lock) and returns.
-
      • 
-
    • 
-The function will unblock when signaled by a call to notify_one(),
-a call to notify_all(), by 
-the current time exceeding abs_time if Clock::now() >= abs_time,
-or spuriously.
-
      • 
-
    • 
-If the function exits via an exception, lock.unlock() shall be called prior
-to exiting the function scope.
-
      • 
-
    
-
-
    
--17- Postcondition: lock is locked by the calling thread.
-
    
-
-
    
--18- Returns: Clock::now() < abs_time
-cv_status::timeout if the function unblocked because abs_time
-was reached, otherwise cv_status::no_timeout.
-
    
-
-
    
--19- Throws: std::system_error when the effects or postcondition
-cannot be achieved.
-
    
-
-
    
--20- Error conditions:
-
    
-
-
      
-
    • 
-operation_not_permitted — if the thread does not own the lock.
-
      • 
-
    • 
-equivalent error condition from lock.lock() or lock.unlock().
-
      • 
-
    
-
    
-
-
    template <class Rep, class Period>
-  bool cv_status wait_for(unique_lock<mutex>& lock,
-                const chrono::duration<Rep, Period>& rel_time);
-
-
    
-
    
-
    
--21- Effects Returns:
-
    
-
    wait_until(lock, chrono::monotonic_clock::now() + rel_time)
-
    
-
    
--22- Returns: false if the call is returning because the time
-duration specified by rel_time has elapsed, 
-otherwise true.
-
    
-
-
    [
-This part of the wording may conflict with 859 in detail, but does
-not do so in spirit.  If both issues are accepted, there is a logical merge.
-]
    
-
-
    
-
-
    template <class Clock, class Duration, class Predicate> 
-  bool wait_until(unique_lock<mutex>& lock, 
-                  const chrono::time_point<Clock, Duration>& abs_time, 
-                  Predicate pred);
-
    
-
-
    
-
    
--23- Effects:
-
    
-
    while (!pred()) 
-  if (!wait_until(lock, abs_time) == cv_status::timeout) 
-    return pred(); 
-return true;
-
    
-
-
    
--24- Returns: pred().
-
    
-
-
    
--25- [Note:
-The returned value indicates whether the predicate evaluates to
-true regardless of whether the timeout was triggered.
-— end note].
-
    
-
    
-
    
-
-
    
-Change Class condition_variable_any 30.5.2 [thread.condition.condvarany] as indicated:
-
    
-
-
    class condition_variable_any {
-public:
-  ...
-  template <class Lock, class Clock, class Duration>
-    bool cv_status wait_until(Lock& lock,
-                    const chrono::time_point<Clock, Duration>& abs_time);
-  template <class Lock, class Clock, class Duration, class Predicate>
-    bool wait_until(Lock& lock,
-                    const chrono::time_point<Clock, Duration>& abs_time,
-                    Predicate pred);
-
-  template <class Lock, class Rep, class Period>
-    bool cv_status wait_for(Lock& lock,
-                  const chrono::duration<Rep, Period>& rel_time);
-  template <class Lock, class Rep, class Period, class Predicate>
-    bool wait_for(Lock& lock,
-                  const chrono::duration<Rep, Period>& rel_time,
-                  Predicate pred);
-  ...
-};
-
-...
-
-template <class Lock, class Clock, class Duration>
-  bool cv_status wait_until(Lock& lock,
-                  const chrono::time_point<Clock, Duration>& abs_time);
-
    
-
-
    
-
-
    
--13- Effects:
-
    
-
-
      
-
    • 
-Atomically calls lock.unlock() and blocks on *this.
-
      • 
-
    • 
-When unblocked, calls lock.lock() (possibly blocking on the lock) and returns.
-
      • 
-
    • 
-The function will unblock when signaled by a call to notify_one(),
-a call to notify_all(), by 
-the current time exceeding abs_time if Clock::now() >= abs_time,
-or spuriously.
-
      • 
-
    • 
-If the function exits via an exception, lock.unlock() shall be called prior
-to exiting the function scope.
-
      • 
-
    
-
-
    
--14- Postcondition: lock is locked by the calling thread.
-
    
-
-
    
--15- Returns: Clock::now() < abs_time
-cv_status::timeout if the function unblocked because abs_time
-was reached, otherwise cv_status::no_timeout.
-
    
-
-
    
--16- Throws: std::system_error when the effects or postcondition
-cannot be achieved.
-
    
-
-
    
--17- Error conditions:
-
    
-
-
      
-
    • 
-equivalent error condition from lock.lock() or lock.unlock().
-
      • 
-
    
-
    
-
-
    template <class Lock, class Rep, class Period>
-  bool cv_status wait_for(Lock& lock,
-                const chrono::duration<Rep, Period>& rel_time);
-
-
    
-
-
    
-
    
--18- Effects Returns:
-
    
-
    wait_until(lock, chrono::monotonic_clock::now() + rel_time)
-
    
-
-
    
--19- Returns: false if the call is returning because the time
-duration specified by rel_time has elapsed, 
-otherwise true.
-
    
-
-
    [
-This part of the wording may conflict with 859 in detail, but does
-not do so in spirit.  If both issues are accepted, there is a logical merge.
-]
    
-
-
-
    
-
-
    template <class Lock, class Clock, class Duration, class Predicate> 
-  bool wait_until(Lock& lock, 
-                  const chrono::time_point<Clock, Duration>& rel_time abs_time, 
-                  Predicate pred);
-
    
-
-
    
-
    
--20- Effects:
-
    
-
    while (!pred()) 
-  if (!wait_until(lock, abs_time) == cv_status::timeout) 
-    return pred(); 
-return true;
-
    
-
-
    
--21- Returns: pred().
-
    
-
-
    
--22- [Note:
-The returned value indicates whether the predicate evaluates to
-true regardless of whether the timeout was triggered.
-— end note].
-
    
-
    
-
-
    
-
-
-
-
-
-
-
    
-
    859. Monotonic Clock is Conditionally Supported?
    
-
    Section: 30.5 [thread.condition] Status: Ready
- Submitter: Pete Becker Opened: 2008-06-23  Last modified: 2009-07-21
    
-
    View all issues with Ready status.
    
-
    Discussion:
    
-
-
    Related to 958, 959.
    
-
-
    
-N2661
-says that there is a class named monotonic_clock. It also says that this
-name may be a synonym for system_clock, and that it's conditionally
-supported. So the actual requirement is that it can be monotonic or not,
-and you can tell by looking at is_monotonic, or it might not exist at
-all (since it's conditionally supported). Okay, maybe too much
-flexibility, but so be it.
-
    
-
    
-A problem comes up in the threading specification, where several
-variants of wait_for explicitly use monotonic_clock::now(). What is the
-meaning of an effects clause that says
-
    
-
-
    wait_until(lock, chrono::monotonic_clock::now() + rel_time)
-
    
-
-
    
-when monotonic_clock is not required to exist?
-
    
-
-
    [
-San Francisco:
-]
    
-
-
-
    
-
    
-Nick: maybe instead of saying that chrono::monotonic_clock is
-conditionally supported, we could say that it's always there, but not
-necessarily supported..
-
    
-
    
-Beman: I'd prefer a typedef that identifies the best clock to use for
-wait_for locks.
-
    
-
    
-Tom: combine the two concepts; create a duration clock type, but keep
-the is_monotonic test.
-
    
-
    
-Howard: if we create a duration_clock type, is it a typedef or an
-entirely true type?
-
    
-
    
-There was broad preference for a typedef.
-
    
-
    
-Move to Open. Howard to provide wording to add a typedef for
-duration_clock and to replace all uses of monotonic_clock in function
-calls and signatures with duration_clock.
-
    
-
    
-
-
    [
-Howard notes post-San Francisco:
-]
    
-
-
-
    
-
    
-After further thought I do not believe that creating a duration_clock typedef
-is the best way to proceed.  An implementation may not need to use a
-time_point to implement the wait_for functions.
-
    
-
-
    
-For example, on POSIX systems sleep_for can be implemented in terms of
-nanosleep which takes only a duration in terms of nanoseconds.  The current
-working paper does not describe sleep_for in terms of sleep_until.
-And paragraph 2 of 30.2.4 [thread.req.timing] has the words strongly encouraging
-implementations to use monotonic clocks for sleep_for:
-
    
-
-
    
-2 The member functions whose names end in _for take an argument that
-specifies a relative time. Implementations should use a monotonic clock to
-measure time for these functions.
-
    
-
-
    
-I believe the approach taken in describing the effects of sleep_for
-and try_lock_for is also appropriate for wait_for.  I.e. these
-are not described in terms of their _until variants.
-
    
-
-
    
-
-
    [
-2009-07 Frankfurt:
-]
    
-
-
-
    
-
    
-Beman will send some suggested wording changes to Howard.
-
    
-
    
-Move to Ready.
-
    
-
    
-
-
    [
-2009-07-21 Beman added the requested wording changes to 962.
-]
    
-
-
-
-
-
    Proposed resolution:
    
-
    
-Change 30.5.1 [thread.condition.condvar], p21-22:
-
    
-
-
    
-
    template <class Rep, class Period> 
-  bool wait_for(unique_lock<mutex>& lock, 
-                const chrono::duration<Rep, Period>& rel_time);
-
    
-
    
-
    
-Precondition: lock is locked by the calling thread, and either
-
    
-
      
-
    • no other thread is waiting on this condition_variable object or
      • 
-
    • lock.mutex() returns the same value for each of the lock
-arguments supplied by all concurrently waiting threads (via wait,
-wait_for or wait_until).
      • 
-
    
-
    
-21 Effects:
-
    
-
    wait_until(lock, chrono::monotonic_clock::now() + rel_time)
-
    
-
      
-
    • 
-Atomically calls lock.unlock() and blocks on *this.
-
      • 
-
-
    • 
-When unblocked, calls lock.lock() (possibly blocking on the lock) and returns.
-
      • 
-
-
    • 
-The function will unblock when signaled by a call to notify_one(), a call
-to notify_all(), by 
-the elapsed time rel_time passing (30.2.4 [thread.req.timing]),
-or spuriously.
-
      • 
-
-
    • 
-If the function exits via an exception, lock.unlock() shall be called 
-prior to exiting the function scope.
-
      • 
-
    
-
-
    
-Postcondition: lock is locked by the calling thread.
-
    
-
-
-
    
-22 Returns: false if the call is returning because the time
-duration specified by rel_time has elapsed, otherwise true.
-
    
-
-
    [
-This part of the wording may conflict with 857 in detail, but does
-not do so in spirit.  If both issues are accepted, there is a logical merge.
-]
    
-
-
-
    
-Throws: std::system_error when the effects or postcondition cannot be achieved.
-
    
-
-
    
-Error conditions:
-
    
-
-
      
-
    • 
-operation_not_permitted -- if the thread does not own the lock.
-
      • 
-
    • 
-equivalent error condition from lock.lock() or lock.unlock().
-
      • 
-
    
-
-
    
-
    
-
-
    
-Change 30.5.1 [thread.condition.condvar], p26-p29:
-
    
-
-
    
-
    template <class Rep, class Period, class Predicate> 
-  bool wait_for(unique_lock<mutex>& lock, 
-                const chrono::duration<Rep, Period>& rel_time, 
-                Predicate pred);
-
    
-
    
-
    
-Precondition: lock is locked by the calling thread, and either
-
    
-
      
-
    • no other thread is waiting on this condition_variable object or
      • 
-
    • lock.mutex() returns the same value for each of the lock
-arguments supplied by all concurrently waiting threads (via wait,
-wait_for or wait_until).
      • 
-
    
-
    
-26 Effects:
-
    
-
    wait_until(lock, chrono::monotonic_clock::now() + rel_time, std::move(pred))
-
    
-
      
-
    • 
-Executes a loop:  Within the loop the function first evaluates pred()
-and exits the loop if the result of pred() is true.
-
      • 
-
    • 
-Atomically calls lock.unlock()
-and blocks on *this.
-
      • 
-
    • 
-When unblocked, calls lock.lock() (possibly blocking on the lock).
-
      • 
-
    • 
-The function will unblock when signaled by a call to notify_one(), a
-call to notify_all(), by the elapsed time rel_time passing (30.1.4
-[thread.req.timing]), or spuriously.
-
      • 
-
    • 
-If the function exits via an exception, lock.unlock() shall be called
-prior to exiting the function scope.
-
      • 
-
    • 
-The loop terminates when pred() returns true or when the time
-duration specified by rel_time has elapsed.
-
      • 
-
    
-
    
-
-
    
-27 [Note: There is no blocking if pred() is initially true,
-even if the timeout has already expired. -- end note]
-
    
-
-
    
-Postcondition: lock is locked by the calling thread.
-
    
-
-
    
-28 Returns: pred()
-
    
-
-
    
-29 [Note: The returned value indicates whether the predicate evaluates to
-true regardless of whether the timeout was triggered. -- end note]
-
    
-
-
    
-Throws: std::system_error when the effects or postcondition cannot be achieved.
-
    
-
-
    
-Error conditions:
-
    
-
-
      
-
    • 
-operation_not_permitted -- if the thread does not own the lock.
-
      • 
-
    • 
-equivalent error condition from lock.lock() or lock.unlock().
-
      • 
-
    
-
-
    
-
    
-
-
    
-Change 30.5.2 [thread.condition.condvarany], p18-19:
-
    
-
-
    
-
    template <class Lock, class Rep, class Period> 
-  bool wait_for(Lock& lock, const chrono::duration<Rep, Period>& rel_time);
-
    
-
    
-
    
-18 Effects:
-
    
-
    wait_until(lock, chrono::monotonic_clock::now() + rel_time)
-
    
-
-
      
-
    • 
-Atomically calls lock.unlock() and blocks on *this.
-
      • 
-
-
    • 
-When unblocked, calls lock.lock() (possibly blocking on the lock) and returns.
-
      • 
-
-
    • 
-The function will unblock when signaled by a call to notify_one(), a call to
-notify_all(), by
-the elapsed time rel_time passing (30.2.4 [thread.req.timing]),
-or spuriously.
-
      • 
-
-
    • 
-If the function exits via an exception, lock.unlock() shall be called
-prior to exiting the function scope.
-
      • 
-
    
-
-
    
-Postcondition: lock is locked by the calling thread.
-
    
-
-
    
-19 Returns: false if the call is returning because the time duration
-specified by rel_time has elapsed, otherwise true.
-
    
-
-
    
-Throws: std::system_error when the returned value, effects,
-or postcondition cannot be achieved.
-
    
-
-
    
-Error conditions:
-
    
-
-
      
-
    • 
-equivalent error condition from lock.lock() or lock.unlock().
-
      • 
-
    
-
    
-
    
-
-
    
-Change 30.5.2 [thread.condition.condvarany], p23-p26:
-
    
-
-
    
-
    template <class Lock, class Rep, class Period, class Predicate> 
-  bool wait_for(Lock& lock, const chrono::duration<Rep, Period>& rel_time, Predicate pred);
-
    
-
    
-
    
-Precondition: lock is locked by the calling thread, and either
-
    
-
      
-
    • no other thread is waiting on this condition_variable object or
      • 
-
    • lock.mutex() returns the same value for each of the lock
-arguments supplied by all concurrently waiting threads (via wait,
-wait_for or wait_until).
      • 
-
    
-
    
-23 Effects:
-
    
-
    wait_until(lock, chrono::monotonic_clock::now() + rel_time, std::move(pred))
-
    
-
      
-
    • 
-Executes a loop:  Within the loop the function first evaluates pred()
-and exits the loop if the result of pred() is true.
-
      • 
-
    • 
-Atomically calls lock.unlock()
-and blocks on *this.
-
      • 
-
    • 
-When unblocked, calls lock.lock() (possibly blocking on the lock).
-
      • 
-
    • 
-The function will unblock when signaled by a call to notify_one(), a
-call to notify_all(), by the elapsed time rel_time passing (30.1.4
-[thread.req.timing]), or spuriously.
-
      • 
-
    • 
-If the function exits via an exception, lock.unlock() shall be called
-prior to exiting the function scope.
-
      • 
-
    • 
-The loop terminates when pred() returns true or when the time
-duration specified by rel_time has elapsed.
-
      • 
-
    
-
    
-
-
    
-24 [Note: There is no blocking if pred() is initially true,
-even if the timeout has already expired. -- end note]
-
    
-
-
    
-Postcondition: lock is locked by the calling thread.
-
    
-
-
    
-25 Returns: pred()
-
    
-
-
    
-26 [Note: The returned value indicates whether the predicate evaluates to
-true regardless of whether the timeout was triggered. -- end note]
-
    
-
-
    
-Throws: std::system_error when the effects or postcondition cannot be achieved.
-
    
-
-
    
-Error conditions:
-
    
-
-
      
-
    • 
-operation_not_permitted -- if the thread does not own the lock.
-
      • 
-
    • 
-equivalent error condition from lock.lock() or lock.unlock().
-
      • 
-
    
-
-
    
-
    
-
-
-
-
-
-
-
 
    
 
    860. Floating-Point State
    
-
    Section: 26 [numerics] Status: Open
- Submitter: Lawrence Crowl Opened: 2008-06-23  Last modified: 2009-03-09
    
+
    Section: 26 [numerics] Status: Ready
+ Submitter: Lawrence Crowl Opened: 2008-06-23  Last modified: 2009-10-23
    
 
    View all other issues in [numerics].
    
-
    View all issues with Open status.
    
+
    View all issues with Ready status.
    
 
    Discussion:
    
 
    
 There are a number of functions that affect the floating point state.
@@ -12825,11 +8494,49 @@ commentary.
    +

    [ +2009-09-23 Hans provided wording. +]

    + + +
    +If I understand the history correctly, Nick, as the Posix liaison, +should probably get a veto on this, since I think it came from Posix (?) +via WG14 and should probably really be addressed there (?). But I think +we are basically in agreement that there is no other sane way to do +this, and hence we don't have to worry too much about stepping on toes. +As far as I can tell, this same issue also exists in the latest Posix +standard (?). +
    + +

    [ +2009-10 Santa Cruz: +]

    + + +
    +Moved to Ready. +
    + +

    Proposed resolution:

    +Add at the end of 26.3.1 [cfenv.syn]:

    +
    +

    +2 The header defines all functions, types, and macros the same as C99 7.6. +

    + +

    +A separate floating point environment shall be maintained for each +thread. Each function accesses the environment corresponding to its +calling thread. +

    +
    + @@ -12837,7 +8544,7 @@ commentary.

    861. Incomplete specification of EqualityComparable for std::forward_list

    Section: 23.2 [container.requirements] Status: Open - Submitter: Daniel Krügler Opened: 2008-06-24 Last modified: 2009-07-26

    + Submitter: Daniel Krügler Opened: 2008-06-24 Last modified: 2009-10-24

    View other active issues in [container.requirements].

    View all other issues in [container.requirements].

    View all issues with Open status.

    @@ -12932,6 +8639,27 @@ Howard: Commented out options A and B. ]

    +

    [ +2009-10 Santa Cruz: +]

    + + +
    +Mark NAD Editorial. Addressed by +N2986. +
    + +

    [ +2009-10 Santa Cruz: +]

    + + +
    +Reopened. +N2986 +was rejected in full committee on procedural grounds. +
    +

    Proposed resolution:

    @@ -13219,9 +8947,9 @@ Change the text in the Assertion/note column in the row for

    865. More algorithms that throw away information

    -

    Section: 25.4.6 [alg.fill], 25.4.7 [alg.generate] Status: Open - Submitter: Daniel Krügler Opened: 2008-07-13 Last modified: 2009-07-25

    -

    View all issues with Open status.

    +

    Section: 25.3.6 [alg.fill], 25.3.7 [alg.generate] Status: Ready + Submitter: Daniel Krügler Opened: 2008-07-13 Last modified: 2009-10-23

    +

    View all issues with Ready status.

    Discussion:

    In regard to library defect 488 I found some more algorithms which @@ -13242,7 +8970,7 @@ void generate_n(OutputIterator first, Size n, Generator gen);

    • In both cases the minimum requirements on the iterator are OutputIterator, which means according to the requirements of -24.2.3 [output.iterators]/2 that only single-pass iterations are guaranteed. +24.2.2 [output.iterators]/2 that only single-pass iterations are guaranteed. So, if users of fill_n and generate_n have *only* an OutputIterator available, they have no chance to continue pushing further values into it, which seems to be a severe limitation to me. @@ -13288,6 +9016,15 @@ to deconceptify it. ]

    +

    [ +2009-10 Santa Cruz: +]

    + + +
    +Moved to Ready. +
    +

    Proposed resolution:

    @@ -13296,7 +9033,7 @@ to deconceptify it.

  • Replace the current declaration of fill_n in 25 [algorithms]/2, header -<algorithm> synopsis and in 25.4.6 [alg.fill] by +<algorithm> synopsis and in 25.3.6 [alg.fill] by 

    template<class OutputIterator, class Size, class T>
@@ -13316,7 +9053,7 @@ returns first for fill_n.
 
  • 
 
    
 Replace the current declaration of generate_n in 25 [algorithms]/2,
-header <algorithm> synopsis and in 25.4.7 [alg.generate] by
+header <algorithm> synopsis and in 25.3.7 [alg.generate] by
 
    
 
 
    template<class OutputIterator, class Size, class Generator>
@@ -13342,11 +9079,11 @@ returns first for generate_n.
 
 
    
 
    868. default construction and value-initialization
    
-
    Section: 23 [containers] Status: Review
- Submitter: Alberto Ganesh Barbati Opened: 2008-07-22  Last modified: 2009-07-19
    
+
    Section: 23 [containers] Status: Ready
+ Submitter: Alberto Ganesh Barbati Opened: 2008-07-22  Last modified: 2009-10-20
    
 
    View other active issues in [containers].
    
 
    View all other issues in [containers].
    
-
    View all issues with Review status.
    
+
    View all issues with Ready status.
    
 
    Discussion:
    
 
    
 The term "default constructed" is often used in wording that predates
@@ -13374,7 +9111,7 @@ Dennett will review the library and provide a complete list and will
 double-check the vocabulary.
 
    
 
    
-This issue relates to Issue 886 tuple construction
+This issue relates to Issue 886 tuple construction
 
    
 
    
 
@@ -13400,7 +9137,7 @@ If wording is forthcoming, Howard will move it back to Review.
 
 
    
 
    
-Howard:  Moved back to Review.  Note that X [utility.arg.requirements]
+Howard:  Moved back to Review.  Note that 20.2.1 [utility.arg.requirements]
 refers to a section that is not in the current working paper, but does refer to
 a section that we expect to reappear after the de-concepts merge.  This was a
 point of confusion we did not recognize when we reviewed this issue in Frankfurt.
@@ -13418,33 +9155,144 @@ proposed
 
    
 In the following paragraphs, we are not proposing changes because
 it's not clear whether we actually prefer value-initialization over
-default-initialization (now partially covered by 1012):
+default-initialization (now partially covered by 1012):
 
    
 
      
-	
    • 20.8.9.2.1 [unique.ptr.single.ctor] para 3 e 7
      • 
-	
    • 24.5.1.2.1 [reverse.iter.cons] para 1
      • 
-	
    • 24.5.2.2.1 [move.iter.op.const] para 1
      • 
+    
    • 20.8.14.2.1 [unique.ptr.single.ctor] para 3 e 7
      • 
+    
    • 24.5.1.3.1 [reverse.iter.cons] para 1
      • 
+    
    • 24.5.3.3.1 [move.iter.op.const] para 1
      • 
 
    
 
    In the following paragraphs, the expression "default
 constructed" need not be changed, because the relevant type does
 not depend on a template parameter and has a user-provided
 constructor:
    
 
      
-	
    •  [func.referenceclosure.invoke] para 12, type:
-	reference_closure
      • 
-	
    • 30.3.1.2 [thread.thread.constr] para 30, type: thread
      • 
-	
    • 30.3.1.5 [thread.thread.member] para 52, type: thread_id
      • 
-	
    • 30.3.2 [thread.thread.this], para 1, type: thread_id
      • 
+    
    •  [func.referenceclosure.invoke] para 12, type:
+    reference_closure
      • 
+    
    • 30.3.1.2 [thread.thread.constr] para 30, type: thread
      • 
+    
    • 30.3.1.5 [thread.thread.member] para 52, type: thread_id
      • 
+    
    • 30.3.2 [thread.thread.this], para 1, type: thread_id
      •
    • +

    [ +2009-08-18 Daniel adds: +]

    + + +
    +

    +I have no objections against the currently suggested changes, but I +also cross-checked +with the list regarding intentionally excluded changes, and from this +I miss the discussion +of +

    + +
      +
    1. +

      +21.4.1 [string.require]/2: +

      + +
      +"[..] The Allocator object used shall be a copy of the Allocator> +object passed to the basic_string object's +constructor or, if the constructor does not take an Allocator +argument, a copy of a default-constructed +Allocator object." +
      +
      2. + +
    2. +

      +N2723, +X [rand.req.eng], Table 109, expression "T()": +

      +
      +Pre-/post-condition: "Creates an engine with the same initial state as +all other default-constructed engines of type X." +
      + +

      +as well as in 26.5.5 [rand.predef]/1-9 (N2914), 26.5.7.1 [rand.util.seedseq]/3, 27.7.1.1.1 [istream.cons]/3, 27.7.2.2 [ostream.cons]/9 (N2914), 28.13 [re.grammar]/2, 30.3.1.4 [thread.thread.assign]/1 (N2914), +

      +

      [ +Candidates for the "the expression "default constructed" need not be +changed" list +]

      + + +

      +I'm fine, if these would be added to the intentionally exclusion list, +but mentioning them makes it +easier for other potential reviewers to decide on the relevance or +not-relevance of them for this issue. +

      +
      3. + +
    3. +

      +I suggest to remove the reference of [func.referenceclosure.invoke] +in the "it's not clear" list, because +this component does no longer exist. +

      +
      4. + +
    4. +

      +I also suggest to add a short comment that all paragraphs in the +resolution whether they refer to N2723 or to N2914 numbering, because e.g. "Change 23.3.2.1 [deque.cons] para 5" is an N2723 coordinate, while "Change 23.3.2.2 [deque.capacity] para 1" is an N2914 coordinate. Even better would be to use one default document +for the numbering (probably N2914) and mention special cases (e.g. "Change 20.2.1 [utility.arg.requirements] para 2" as referring to N2723 numbering). +

      +
      5. +
    + +
    + +

    [ +2009-08-18 Alisdair adds: +]

    + + +
    +

    +I strongly believe the term "default constructed" should not appear in +the library clauses unless we very clearly define a meaning for it, and +I am not sure what that would be. +

    + +

    +In those cases where we do not want to replace "default constructed" +with "vale initialized" we should be using "default initialized". If we +have a term that could mean either, we reduce portability of programs. +

    + +

    +I have not done an exhaustive review to clarify if that is a vendor +freedom we have reason to support (e.g. value-init in debug, +default-init in release) so I may yet be convinced that LWG has reason +to define this new term of art, but generally C++ initialization is +confusing enough without supporting further ill-defined terms. +

    +
    + +

    [ +2009-10 Santa Cruz: +]

    + + +
    +Move to Ready. +
    +

    Proposed resolution:

    -Change X [utility.arg.requirements] para 2: +Change 20.2.1 [utility.arg.requirements] para 2:

    @@ -13551,7 +9399,7 @@ elements to the sequence.

    870. Do unordered containers not support function pointers for predicate/hasher?

    Section: 23.2.5 [unord.req] Status: Open - Submitter: Daniel Krügler Opened: 2008-08-17 Last modified: 2009-07-28

    + Submitter: Daniel Krügler Opened: 2008-08-17 Last modified: 2009-10-20

    View other active issues in [unord.req].

    View all other issues in [unord.req].

    View all issues with Open status.

    @@ -13625,6 +9473,21 @@ the following ]

    +

    [ +2009-10 Santa Cruz: +]

    + + +
    +Ask Daniel to provide proposed wording that: makes it explicit that +function pointers are function objects at the beginning of 20.7 [function.objects]; fixes the "requirements" for typedefs in +20.7.5 [refwrap] to instead state that the function objects +defined in that clause have these typedefs, but not that these typedefs +are requirements on function objects; remove the wording that explicitly +calls out that associative container comparators may be function +pointers. +
    +

    Proposed resolution:

    @@ -13682,9 +9545,9 @@ This is fixed by

    871. Iota's requirements on T are too strong

    -

    Section: 26.7.5 [numeric.iota] Status: Review - Submitter: Daniel Krügler Opened: 2008-08-20 Last modified: 2009-07-30

    -

    View all issues with Review status.

    +

    Section: 26.7.5 [numeric.iota] Status: Ready + Submitter: Daniel Krügler Opened: 2008-08-20 Last modified: 2009-10-22

    +

    View all issues with Ready status.

    Discussion:

    According to the recent WP @@ -13732,6 +9595,15 @@ suggest to reopen it. I also revised by proposed resolution based on N2723 wording:

    +

    [ +2009-10 Santa Cruz: +]

    + + +
    +Change 'convertible' to 'assignable', Move To Ready. +
    +

    Proposed resolution:

    @@ -13742,7 +9614,7 @@ Change the first sentence of 26.7.5 [numeric.iota]/1:
    Requires: T shall meet the requirements of CopyConstructible and Assignable types, and shall be -convertible to ForwardIterator's value type. [..] +assignable to ForwardIterator's value type. [..]
    @@ -13754,9 +9626,9 @@ convertible to ForwardIterator's value type. [..]

    872. move_iterator::operator[] has wrong return type

    -

    Section: 24.5.2.2.12 [move.iter.op.index] Status: Open - Submitter: Doug Gregor Opened: 2008-08-21 Last modified: 2009-07-28

    -

    View all issues with Open status.

    +

    Section: 24.5.3.3.12 [move.iter.op.index] Status: Ready + Submitter: Doug Gregor Opened: 2008-08-21 Last modified: 2009-10-23

    +

    View all issues with Ready status.

    Discussion:

    move_iterator's operator[] is declared as: @@ -13778,11 +9650,31 @@ we dealt with for reverse_iterator in DR 1051 which addresses +this issue for both move_iterator and reverse_iterator. + + +

    [ +2009-10 Santa Cruz: +]

    + + +
    +Move to Ready. Note that if 1051 is reopened, it may yield a +better resolution, but 1051 is currently marked NAD. +
    +

    Proposed resolution:

    -In 24.5.2.1 [move.iterator] and 24.5.2.2.12 [move.iter.op.index], change the declaration of +In 24.5.3.1 [move.iterator] and 24.5.3.3.12 [move.iter.op.index], change the declaration of move_iterator's operator[] to:

    @@ -13805,483 +9697,9 @@ NAD Editorial, see -
    -

    876. basic_string access operations should give stronger guarantees

    -

    Section: 21.4 [basic.string] Status: Ready - Submitter: Daniel Krügler Opened: 2008-08-22 Last modified: 2009-07-17

    -

    View all other issues in [basic.string].

    -

    View all issues with Ready status.

    -

    Discussion:

    -

    -During the Sophia Antipolis meeting it was decided to split-off some -parts of the -n2647 -("Concurrency modifications for basic_string") -proposal into a separate issue, because these weren't actually -concurrency-related. The here proposed changes refer to the recent -update document -n2668 -and attempt to take advantage of the -stricter structural requirements. -

    -

    -Indeed there exists some leeway for more guarantees that would be -very useful for programmers, especially if interaction with transactionary -or exception-unaware C API code is important. This would also allow -compilers to take advantage of more performance optimizations, because -more functions can have throw() specifications. This proposal uses the -form of "Throws: Nothing" clauses to reach the same effect, because -there already exists a different issue in progress to clean-up the current -existing "schizophrenia" of the standard in this regard. -

    -

    -Due to earlier support for copy-on-write, we find the following -unnecessary limitations for C++0x: -

    - -
      -
    1. -Missing no-throw guarantees: data() and c_str() simply return -a pointer to their guts, which is a non-failure operation. This should -be spelled out. It is also noteworthy to mention that the same -guarantees should also be given by the size query functions, -because the combination of pointer to content and the length is -typically needed during interaction with low-level API. -
      2. -
    2. -Missing complexity guarantees: data() and c_str() simply return -a pointer to their guts, which is guaranteed O(1). This should be -spelled out. -
      3. -
    3. -Missing reading access to the terminating character: Only the -const overload of operator[] allows reading access to the terminator -char. For more intuitive usage of strings, reading access to this -position should be extended to the non-const case. In contrast -to C++03 this reading access should now be homogeneously -an lvalue access. -
      4. -
    - -

    -The proposed resolution is split into a main part (A) and a -secondary part (B) (earlier called "Adjunct Adjunct Proposal"). -(B) extends (A) by also making access to index position -size() of the at() overloads a no-throw operation. This was -separated, because this part is theoretically observable in -specifically designed test programs. -

    - -

    [ -San Francisco: -]

    - - -
    -

    -We oppose part 1 of the issue but hope to address size() in -issue 877. -

    -

    -We do not support part B. 4 of the issue because of the breaking API change. -

    -

    -We support part A. 2 of the issue. -

    -

    -On support part A. 3 of the issue: -

    -
    -Pete's broader comment: now that we know that basic_string will be a -block of contiguous memory, we should just rewrite its specification -with that in mind. The expression of the specification will be simpler -and probably more correct as a result. -
    -
    - -

    [ -2009-07 Frankfurt -]

    - - -
    -

    -Move proposed resolution A to Ready. -

    -

    [ -Howard: Commented out part B. -]

    - -
    - - - -

    Proposed resolution:

    -
      -
    1. -
        -
      1. -

        In 21.4.4 [string.capacity], just after p. 1 add a new paragraph: -

        -
        -Throws: Nothing. -
        - -
        2. -
      2. -

        -In 21.4.5 [string.access] replace p. 1 by the following 4 paragraghs: -

        - -
        -

        -Requires: pos ≤ size(). -

        -

        -Returns: If pos < size(), returns *(begin() + pos). Otherwise, returns -a reference to a charT() that shall not be modified. -

        -

        -Throws: Nothing. -

        -

        -Complexity: Constant time. -

        -
        - -
        3. -
      3. -

        -In 21.4.7.1 [string.accessors] replace the now common returns -clause of c_str() and data() by the following three paragraphs: -

        -
        -

        -Returns: A pointer p such that p+i == &operator[](i) for each i -in [0, size()]. -

        -

        -Throws: Nothing. -

        -

        -Complexity: Constant time. -

        -
        -
        4. -
      -
      2. - -
    - - - - - - -
    -

    879. Atomic load const qualification

    -

    Section: 29 [atomics] Status: Open - Submitter: Alexander Chemeris Opened: 2008-08-24 Last modified: 2009-07-17

    -

    View other active issues in [atomics].

    -

    View all other issues in [atomics].

    -

    View all issues with Open status.

    -

    Discussion:

    -

    -The atomic_address type and atomic<T*> specialization provide atomic -updates to pointers. However, the current specification requires -that the types pointer be to non-const objects. This restriction -is unnecessary and unintended. -

    - -

    [ -Summit: -]

    - -
    -Move to review. Lawrence will first check with Peter whether the -current examples are sufficient, or whether they need to be expanded to -include all cases. -
    - -

    [ -2009-07 Frankfurt -]

    - - -
    -

    -Lawrence will handle all issues relating to atomics in a single paper. -

    -

    -LWG will defer discussion on atomics until that paper appears. -

    -

    -Move to Open. -

    -
    - - - -

    Proposed resolution:

    -

    -Add const qualification to the pointer values of the atomic_address -and atomic<T*> specializations. E.g. -

    - -
    typedef struct atomic_address {
-   void store(const void*, memory_order = memory_order_seq_cst) volatile;
-   void* exchange( const void*, memory_order = memory_order_seq_cst) volatile;
-   bool compare_exchange( const void*&, const void*,
-                          memory_order, memory_order) volatile;
-   bool compare_exchange( const void*&, const void*,
-                          memory_order = memory_order_seq_cst ) volatile;
-   void* operator=(const void*) volatile;
-} atomic_address;
-
-void atomic_store(volatile atomic_address*, const void*);
-void atomic_store_explicit(volatile atomic_address*, const void*,
-                          memory_order);
-void* atomic_exchange(volatile atomic_address*, const void*);
-void* atomic_exchange_explicit(volatile atomic_address*, const void*,
-                              memory_order);
-bool atomic_compare_exchange(volatile atomic_address*,
-                            const void**, const void*);
-bool atomic_compare_exchange_explicit(volatile atomic_address*,
-                                     const void**, const void*,
-                                     memory_order, memory_order);
-
    - - - - - -
    -

    880. Missing atomic exchange parameter

    -

    Section: 29 [atomics] Status: Open - Submitter: Lawrence Crowl Opened: 2008-08-24 Last modified: 2009-07-17

    -

    View other active issues in [atomics].

    -

    View all other issues in [atomics].

    -

    View all issues with Open status.

    -

    Duplicate of: 942

    -

    Discussion:

    -

    -The atomic_exchange and atomic_exchange_explicit functions seem to -be inconsistently missing parameters. -

    - -

    [ -Post Summit: -]

    - - -
    -

    -Lawrence: Need to write up a list for Pete with details. -

    -

    -Detlef: Should not be New, we already talked about in Concurrency group. -

    -

    -Recommend Open. -

    -
    - -

    [ -2009-07 Frankfurt -]

    - - -
    -

    -Lawrence will handle all issues relating to atomics in a single paper. -

    -

    -LWG will defer discussion on atomics until that paper appears. -

    -

    -Move to Open. -

    -
    - - - -

    Proposed resolution:

    -

    -Add the appropriate parameters. For example, -

    - -
    bool atomic_exchange(volatile atomic_bool*, bool);
-bool atomic_exchange_explicit(volatile atomic_bool*, bool, memory_order);
-
    - - - - - -
    -

    881. shared_ptr conversion issue

    -

    Section: 20.8.10.2.1 [util.smartptr.shared.const] Status: Ready - Submitter: Peter Dimov Opened: 2008-08-30 Last modified: 2009-07-17

    -

    View other active issues in [util.smartptr.shared.const].

    -

    View all other issues in [util.smartptr.shared.const].

    -

    View all issues with Ready status.

    -

    Discussion:

    -

    -We've changed shared_ptr<Y> to not convert to shared_ptr<T> when Y* -doesn't convert to T* by resolving issue 687. This only fixed the -converting copy constructor though. -N2351 -later added move support, and -the converting move constructor is not constrained. -

    - -

    [ -San Francisco: -]

    - - -
    -We might be able to move this to NAD, Editorial once shared_ptr is -conceptualized, but we want to revisit this issue to make sure. -
    - -

    [ -2009-07 Frankfurt -]

    - - -
    -

    -Moved to Ready. -

    -

    -This issue now represents the favored format for specifying constrained templates. -

    -
    - - - -

    Proposed resolution:

    -

    -We need to change the Requires clause of the move constructor: -

    - -
    shared_ptr(shared_ptr&& r); 
-template<class Y> shared_ptr(shared_ptr<Y>&& r); 
-
    -
    -Requires Remarks: For the second constructor Y* shall be -convertible to T*. - -The second constructor shall not participate in overload resolution -unless Y* is convertible to T*. - -
    -
    - -

    -in order to actually make the example in 687 compile -(it now resolves to the move constructor). -

    - - - - - - -
    -

    883. swap circular definition

    -

    Section: 23 [containers] Status: Ready - Submitter: Alisdair Meredith Opened: 2008-09-10 Last modified: 2009-07-17

    -

    View other active issues in [containers].

    -

    View all other issues in [containers].

    -

    View all issues with Ready status.

    -

    Discussion:

    - -

    -Note in particular that Table 90 "Container Requirements" gives -semantics of a.swap(b) as swap(a,b), yet for all -containers we define swap(a,b) to call a.swap(b) - a -circular definition. -

    - -

    [ -San Francisco: -]

    - - -
    -Robert to propose a resolution along the lines of "Postcondition: "a = -b, b = a" This will be a little tricky for the hash containers, since -they don't have operator==. -
    - -

    [ -Post Summit Anthony Williams provided proposed wording. -]

    - - -

    [ -2009-07 Frankfurt -]

    - - -
    -Moved to Ready with minor edits (which have been made). -
    - - - -

    Proposed resolution:

    -

    -In table 80 in section 23.2.1 [container.requirements.general], -replace the postcondition of a.swap(b) with the following: -

    - -
    - - - - - - - - - - - - - - - - - - - - - - - -
    Table 80 -- Container requirements
    ExpressionReturn typeOperational semanticsAssertion/note pre-/post-conidtionComplexity
    ...............
    a.swap(b);void swap(a,b) -Exchange the contents of a and b.(Note A)
    -
    - -

    -Remove the reference to swap from the paragraph following the table. -

    - -
    -Notes: the algorithms swap(), equal() and -lexicographical_compare() are defined in Clause 25. ... -
    - - - - -

    885. pair assignment

    -

    Section: 20.3.3 [pairs] Status: Open +

    Section: 20.3.4 [pairs] Status: Open Submitter: Alisdair Meredith Opened: 2008-09-15 Last modified: 2009-07-17

    View other active issues in [pairs].

    View all other issues in [pairs].

    @@ -14362,113 +9780,10 @@ We agree with the intent, but we need to wait for the dust to settle on concepts -
    -

    886. tuple construction

    -

    Section: 20.5.2.1 [tuple.cnstr] Status: Ready - Submitter: Alisdair Meredith Opened: 2008-09-15 Last modified: 2009-07-17

    -

    View other active issues in [tuple.cnstr].

    -

    View all other issues in [tuple.cnstr].

    -

    View all issues with Ready status.

    -

    Discussion:

    -

    -20.5.2.1 [tuple.cnstr]: -

    -
    -Effects: Default initializes each element. -
    - -

    -Could be clarified to state each "non-trivial" element. Otherwise -we have a conflict with Core deinfition of default initialization - -trivial types do not get initialized (rather than initialization -having no effect) -

    - -

    -I'm going to punt on this one, because it's not an issue that's -related to concepts. I suggest bringing it to Howard's attention on -the reflector. -

    - -

    [ -San Francisco: -]

    - - -
    -

    -Text in draft doesn't mean anything, changing to "non-trivial" makes it -meaningful. -

    -

    -We prefer "value initializes". Present implementations use -value-initialization. Users who don't want value initialization have -alternatives. -

    -

    -Request resolution text from Alisdair. -

    - -

    -This issue relates to Issue 868 default construction and value-initialization. -

    -
    - -

    [ -2009-05-04 Alisdair provided wording and adds: -]

    - - -
    -

    -Note: This IS a change of semantic from TR1, although one the room agreed -with during the discussion. To preserve TR1 semantics, this would have been -worded: -

    -
    requires DefaultConstructible<Types>... tuple();
-
    -
    --2- Effects: Default-initializes each non-trivial element. -
    -
    - - -
    - -

    [ -2009-07 Frankfurt -]

    - - -
    -Move to Ready. -
    - - - -

    Proposed resolution:

    -

    -Change p2 in Construction 20.5.2.1 [tuple.cnstr]: -

    - -
    requires DefaultConstructible<Types>... tuple();
-
    -
    -

    --2- Effects: Default Value-initializes each element. -

    -
    -
    - - - - - -

    887. issue with condition::wait_...

    Section: 30.5.1 [thread.condition.condvar] Status: Open - Submitter: Lawrence Crowl Opened: 2008-09-15 Last modified: 2009-07-26

    + Submitter: Lawrence Crowl Opened: 2008-09-15 Last modified: 2009-10-26

    View other active issues in [thread.condition.condvar].

    View all other issues in [thread.condition.condvar].

    View all issues with Open status.

    @@ -14515,8 +9830,8 @@ condition_variable::wait_until(unique_lock<mutex>& lock, const chrono::time_point<Clock, Duration>& abs_time) { using namespace chrono; - typename Clock::time_point c_entry = Clock::now(); system_clock::time_point s_entry = system_clock::now(); + typename Clock::time_point c_entry = Clock::now(); nanoseconds dn = __round_up<nanoseconds>(abs_time.time_since_epoch() - c_entry.time_since_epoch()); __do_timed_wait(lock.mutex()->native_handle(), s_entry + dn); @@ -14718,6 +10033,22 @@ not have good wording for such a note, but welcome suggestions. +

    [ +2009-09-30: See N2969. +]

    + + +

    [ +2009-10 Santa Cruz: +]

    + + +
    +The LWG is in favor of Detlef to supply revision which adopts Option 2 from +N2969 +but is modified by saying that system_clock must be available for wait_until. +
    +

    Proposed resolution:

    @@ -14730,10 +10061,10 @@ not have good wording for such a note, but welcome suggestions.

    889. thread::id comparisons

    -

    Section: 30.3.1.1 [thread.thread.id] Status: Review - Submitter: Lawrence Crowl Opened: 2008-09-15 Last modified: 2009-07-28

    +

    Section: 30.3.1.1 [thread.thread.id] Status: Ready + Submitter: Lawrence Crowl Opened: 2008-09-15 Last modified: 2009-10-22

    View all other issues in [thread.thread.id].

    -

    View all issues with Review status.

    +

    View all issues with Ready status.

    Discussion:

    Addresses UK 324

    @@ -14770,7 +10101,7 @@ post San Francisco: Howard: It turns out the current working paper N2723 already has hash<thread::id> -(20.7 [function.objects], 20.7.17 [unord.hash]). We simply +(20.7 [function.objects], 20.7.16 [unord.hash]). We simply overlooked it in the meeting. It is a good thing we voted in favor of it (again). :-)

    @@ -14805,7 +10136,7 @@ It is not clear to me that the specification is complete.

    In particular, the synopsis of <functional> in 20.7 [function.objects] does not mention hash< thread::id > nor hash< error_code >, although their -existence is implied by 20.7.17 [unord.hash], p1. +existence is implied by 20.7.16 [unord.hash], p1.

    I am fairly uncomfortable putting the declaration for the @@ -14868,9 +10199,28 @@ header. Alisdair to provide wording. ]

    +

    [ +2009-10 Santa Cruz: +]

    + + +
    +Add a strike for hash<thread::id>. Move to Ready +
    +

    Proposed resolution:

    + +

    +Remove the following prototype from the synopsis in +20.7 [function.objects]: +

    + +
    
+template <> struct hash<std::thread::id>;
+
    +

    Add to 30.3 [thread.threads], p1 Header <thread> synopsis:

    @@ -14908,7 +10258,7 @@ Add new paragraph to end of 30.3.1.1 [thread.thread.id] 
    template <> struct hash<thread::id>;
    -An explicit specializations of the class template hash (20.7.17 [unord.hash]) +An explicit specializations of the class template hash (20.7.16 [unord.hash]) shall be provided for the values of type thread::id suitable for use as keys in unordered associative containers (23.5 [unord]).
    @@ -14921,7 +10271,7 @@ suitable for use as keys in unordered associative containers (23.5 [unord]).

    891. std::thread, std::call_once issue

    Section: 30.3.1.2 [thread.thread.constr], 30.4.5.2 [thread.once.callonce] Status: Open - Submitter: Peter Dimov Opened: 2008-09-15 Last modified: 2009-07-17

    + Submitter: Peter Dimov Opened: 2008-09-15 Last modified: 2009-10-24

    View other active issues in [thread.thread.constr].

    View all other issues in [thread.thread.constr].

    View all issues with Open status.

    @@ -14986,6 +10336,18 @@ Post Summit Anthony provided proposed wording. Leave Open. Await decision for thread variadic constructor.
    +

    [ +2009-10 Santa Cruz: +]

    + + +
    +See proposed wording for 929 for this, for the formulation +on how to solve this. 929 modifies the thread constructor to +have "pass by value" behavior with pass by reference efficiency through the use +of the decay trait. This same formula would be useful for call_once. +
    +

    Proposed resolution:

    @@ -15029,11 +10391,10 @@ valid expression for some values w1, w2, ..., wN, where

    893. std::mutex issue

    -

    Section: 30.4.1.1 [thread.mutex.class] Status: Review - Submitter: Peter Dimov Opened: 2008-09-15 Last modified: 2009-07-31

    -

    View other active issues in [thread.mutex.class].

    +

    Section: 30.4.1.1 [thread.mutex.class] Status: Ready + Submitter: Peter Dimov Opened: 2008-09-15 Last modified: 2009-10-22

    View all other issues in [thread.mutex.class].

    -

    View all issues with Review status.

    +

    View all issues with Ready status.

    Duplicate of: 905

    Discussion:

    @@ -15095,6 +10456,16 @@ Move to Review. Alisdair to provide note. ]

    +

    [ +2009-10 Santa Cruz: +]

    + + +
    +Moved to Ready. +
    + +

    Proposed resolution:

    @@ -15146,9 +10517,8 @@ be observed. — end note]

    896. Library thread safety issue

    -

    Section: 20.8.10.2 [util.smartptr.shared] Status: Open - Submitter: Hans Boehm Opened: 2008-09-16 Last modified: 2009-07-17

    -

    View other active issues in [util.smartptr.shared].

    +

    Section: 20.8.15.2 [util.smartptr.shared] Status: Open + Submitter: Hans Boehm Opened: 2008-09-16 Last modified: 2009-10-25

    View all other issues in [util.smartptr.shared].

    View all issues with Open status.

    Discussion:

    @@ -15262,6 +10632,54 @@ Hans to improve wording in consultation with Pete. Leave Open.

    +

    [ +2009-10 Santa Cruz: +]

    + + +
    +Move to Ready. Ask Editor to clear up wording a little when integrating to +make it clear that the portion after the first comma only applies for +the presence of data races. +
    + +

    [ +2009-10-24 Hans adds: +]

    + + +
    +

    +I think we need to pull 896 back from ready, unfortunately. My wording +doesn't say the right thing. +

    + +

    +I suspect we really want to say something along the lines of: +

    + +
    +For purposes of determining the presence of a data race, member +functions access and modify only the shared_ptr and +weak_ptr objects themselves and not objects they refer to. +Changes in use_count() do not reflect modifications that can +introduce data races. +
    + +

    +But I think this needs further discussion by experts to make sure this +is right. +

    + +

    +Detlef and I agree continue to disagree on the resolution, but I think +we agree that it would be good to try to expedite this so that it can be +in CD2, since it's likely to generate NB comments no matter what we do. +And lack of clarity of intent is probably the worst option. I think it +would be good to look at this between meetings. +

    +
    +

    Proposed resolution:

    @@ -15269,7 +10687,7 @@ Hans to improve wording in consultation with Pete. Leave Open. Make it explicitly thread-safe, in this weak sense, as I believe was intended:

    -Insert in 20.8.10.2 [util.smartptr.shared], before p5: +Insert in 20.8.15.2 [util.smartptr.shared], before p5:

    @@ -15290,330 +10708,10 @@ anywhere else, since nothing else has the problem with the modified -

    -

    897. Forward_list issues... Part 2

    -

    Section: 23.3.3.4 [forwardlist.modifiers] Status: Review - Submitter: Howard Hinnant Opened: 2008-09-22 Last modified: 2009-07-18

    -

    View all issues with Review status.

    -

    Discussion:

    -

    -This issue was split off from 892 at the request of the LWG. -

    - -

    [ -San Francisco: -]

    - - -
    -

    -This issue is more complicated than it looks. -

    -

    -paragraph 47: replace each (first, last) with (first, last] -

    -

    -add a statement after paragraph 48 that complexity is O(1) -

    -

    -remove the complexity statement from the first overload of splice_after -

    -

    -We may have the same problems with other modifiers, like erase_after. -Should it require that all iterators in the range (position, last] be -dereferenceable? -

    -
    - -

    -There are actually 3 issues here: -

    - -
      -
    1. -

      -What value should erase_after return? With list, code often -looks like: -

      -
      for (auto i = l.begin(); i != l.end();)
-{
-    // inspect *i and decide if you want to erase it
-    // ...
-    if (I want to erase *i)
-        i = l.erase(i);
-    else
-        ++i;
-}
-
      -

      -I.e. the iterator returned from erase is useful for setting up the -logic for operating on the next element. For forward_list this might -look something like: -

      -
      auto i = fl.before_begin();
-auto ip1 = i;
-for (++ip1; ip1 != fl.end(); ++ip1)
-{
-    // inspect *(i+1) and decide if you want to erase it
-    // ...
-    if (I want to erase *(i+1))
-        i = fl.erase_after(i);
-    else
-        ++i;
-    ip1 = i;
-}
-
      -

      -In the above example code, it is convenient if erase_after returns -the element prior to the erased element (range) instead of the element -after the erase element (range). -

      -

      -Existing practice: -

      -
        -
      • SGI slist returns an iterator referencing the element after the erased range.
        • -
      • CodeWarrior slist returns an iterator referencing the element before the erased range.
        • -
      -

      -There is not a strong technical argument for either solution over the other. -

      -
      2. - -
    2. -

      -With all other containers, operations always work on the range -[first, last) and/or prior to the given position. -

      -

      -With forward_list, operations sometimes work on the range -(first, last] and/or after the given position. -

      -

      -This is simply due to the fact that in order to operate on -*first (with forward_list) one needs access to -*(first-1). And that's not practical with -forward_list. So the operating range needs to start with (first, -not [first (as the current working paper says). -

      -

      -Additionally, if one is interested in splicing the range (first, last), -then (with forward_list), one needs practical (constant time) access to -*(last-1) so that one can set the next field in this node to -the proper value. As this is not possible with forward_list, one must -specify the last element of interest instead of one past the last element of -interest. The syntax for doing this is to pass (first, last] instead -of (first, last). -

      -

      -With erase_after we have a choice of either erasing the range -(first, last] or (first, last). Choosing the latter -enables: -

      -
      x.erase_after(pos, x.end());
-
      - -

      -With the former, the above statement is inconvenient or expensive due to the lack -of constant time access to x.end()-1. However we could introduce: -

      - -
      iterator erase_to_end(const_iterator position);
-
      - -

      -to compensate. -

      - -

      -The advantage of the former ((first, last]) for erase_after -is a consistency with splice_after which uses (first, last] -as the specified range. But this either requires the addition of erase_to_end -or giving up such functionality. -

      - -
      3. - -
    3. -As stated in the discussion of 892, and reienforced by point 2 above, -a splice_after should work on the source range (first, last] -if the operation is to be Ο(1). When splicing an entire list x the -algorithm needs (x.before_begin(), x.end()-1]. Unfortunately x.end()-1 -is not available in constant time unless we specify that it must be. In order to -make x.end()-1 available in constant time, the implementation would have -to dedicate a pointer to it. I believe the design of -N2543 -intended a nominal overhead of foward_list of 1 pointer. Thus splicing -one entire forward_list into another can not be Ο(1). -
      4. -
    - -

    [ -Batavia (2009-05): -]

    - -
    -

    -We agree with the proposed resolution. -

    -

    -Move to Review. -

    -
    - -

    [ -2009-07 Frankfurt -]

    - - -
    -

    -We may need a new issue to correct splice_after, because it may no -longer be correct to accept an rvalues as an argument. Merge may be -affected, too. This might be issue 1133. (Howard: confirmed) -

    -

    -Move this to Ready, but the Requires clause of the second form of -splice_after should say "(first, last)," not "(first, last]" (there are -three occurrences). There was considerable discussion on this. (Howard: fixed) -

    -

    -Alan suggested removing the "foward_last<T. Alloc>&& x" -parameter from the second form of splice_after, because it is redundant. -PJP wanted to keep it, because it allows him to check for bad ranges -(i.e. "Granny knots"). -

    -

    -We prefer to keep x. -

    -

    -Beman. Whenever we deviate from the customary half-open range in the -specification, we should add a non-normative comment to the standard -explaining the deviation. This clarifies the intention and spares the -committee much confusion in the future. -

    -

    -Alan to write a non-normative comment to explain the use of fully-closed ranges. -

    -

    -Move to Ready, with the changes described above. (Howard: awaiting note from Alan) -

    -
    - - - -

    Proposed resolution:

    -

    -Wording below assumes issue 878 is accepted, but this issue is -independent of that issue. -

    - -

    -Change 23.3.3.4 [forwardlist.modifiers]: -

    - -
    -
    iterator erase_after(const_iterator position);
-
    -
    -

    -Requires: The iterator following position is dereferenceable. -

    -

    -Effects: Erases the element pointed to by the iterator following position. -

    -

    -Returns: An iterator pointing to the element following the one that was erased, or end() if no such -element exists -An iterator equal to position. -

    -
    - - -
    iterator erase_after(const_iterator position, const_iterator last);
-
    -
    -

    -Requires: All iterators in the range -[(position,last) -are dereferenceable. -

    -

    -Effects: Erases the elements in the range -[(position,last). -

    -

    -Returns: An iterator equal to position last -

    -
    -
    - -

    -Change 23.3.3.5 [forwardlist.ops]: -

    - -
    -
    void splice_after(const_iterator position, forward_list<T,Allocator>&& x);
-
    -
    -

    -Requires: position is before_begin() or a -dereferenceable iterator in the range [begin(), end)). &x != this. -

    -

    -Effects: Inserts the contents of x after position, and -x becomes empty. Pointers and references to -the moved elements of x now refer to those same elements but as members of *this. -Iterators referring to the moved elements will continue to refer to their elements, -but they now behave as iterators into *this, not into x. -

    -

    -Throws: Nothing. -

    -

    -Complexity: Ο(1) Ο(distance(x.begin(), x.end())) -

    -
    - -

    ...

    - -
    void splice_after(const_iterator position, forward_list<T,Allocator>&& x, 
-                  const_iterator first, const_iterator last);
-
    -
    -

    -Requires: position is before_begin() or a -dereferenceable iterator in the range [begin(), end)). -(first,last) is a valid range in -x, and all iterators in the range -(first,last) are dereferenceable. -position is not an iterator in the range (first,last). -

    -

    -Effects: Inserts elements in the range (first,last) -after position and removes the elements from x. -Pointers and references to the moved elements of x now refer to -those same elements but as members of *this. Iterators -referring to the moved elements will continue to refer to their -elements, but they now behave as iterators into *this, not into -x. -

    -

    -Complexity: Ο(1). -

    -
    - -
    - - - - - -

    900. stream move-assignment

    Section: 27.9.1.8 [ifstream.assign] Status: Open - Submitter: Niels Dekker Opened: 2008-09-20 Last modified: 2009-07-26

    + Submitter: Niels Dekker Opened: 2008-09-20 Last modified: 2009-10-20

    View all issues with Open status.

    Discussion:

    @@ -15672,6 +10770,26 @@ Howard is going to write wording. ]

    +

    [ +2009-09-13 Niels adds: +]

    + + +
    +Note: The proposed change of 27.9.1.3 [filebuf.assign]/1 depends on the +resolution of LWG 1204, which allows implementations to assume that +*this and rhs refer to different objects. +
    + +

    [ +2009 Santa Cruz: +]

    + + +
    +Leave as Open. Too closely related to 911 to move on at this time. +
    +

    Proposed resolution:

    @@ -15793,81 +10911,12 @@ base and members of rhs. -
    -

    908. Deleted assignment operators for atomic types must be volatile

    -

    Section: 29.5 [atomics.types] Status: Open - Submitter: Anthony Williams Opened: 2008-09-26 Last modified: 2009-03-22

    -

    View all other issues in [atomics.types].

    -

    View all issues with Open status.

    -

    Discussion:

    - -

    Addresses US 90

    - -

    -The deleted copy-assignment operators for the atomic types are not -marked as volatile in N2723, whereas the assignment operators from the -associated non-atomic types are. e.g. -

    -
    atomic_bool& operator=(atomic_bool const&) = delete;
-atomic_bool& operator=(bool) volatile;
-
    - -

    -This leads to ambiguity when assigning a non-atomic value to a -non-volatile instance of an atomic type: -

    -
    atomic_bool b;
-b=false;
-
    - -

    -Both assignment operators require a standard conversions: the -copy-assignment operator can use the implicit atomic_bool(bool) -conversion constructor to convert false to an instance of -atomic_bool, or b can undergo a qualification conversion in order to -use the assignment from a plain bool. -

    - -

    -This is only a problem once issue 845 is applied. -

    - -

    [ -Summit: -]

    - -
    -Move to open. Assign to Lawrence. Related to US 90 comment. -
    - - -

    Proposed resolution:

    -

    -Add volatile qualification to the deleted copy-assignment operator of -all the atomic types: -

    - -
    atomic_bool& operator=(atomic_bool const&) volatile = delete;
-atomic_itype& operator=(atomic_itype const&) volatile = delete;
-
    - -

    -etc. -

    -

    -This will mean that the deleted copy-assignment operator will require -two conversions in the above example, and thus be a worse match than -the assignment from plain bool. -

    - - - - -

    910. Effects of MoveAssignable

    -

    Section: 20.2.9 [concept.copymove] Status: Open - Submitter: Alberto Ganesh Barbati Opened: 2008-09-29 Last modified: 2009-07-18

    +

    Section: 20.2.1 [utility.arg.requirements] Status: Open + Submitter: Alberto Ganesh Barbati Opened: 2008-09-29 Last modified: 2009-11-03

    +

    View other active issues in [utility.arg.requirements].

    +

    View all other issues in [utility.arg.requirements].

    View all issues with Open status.

    Discussion:

    Addresses UK 150

    @@ -16005,11 +11054,21 @@ Need to look at again without concepts. Walter will consult with Dave and Doug.
    +

    [ +2009-10 Santa Cruz: +]

    + + +
    +We believe this is handled by the resolution to issue 1204, +but there is to much going on in this area to be sure. Defer for now. +
    +

    Proposed resolution:

    -In 20.2.9 [concept.copymove], replace the postcondition in paragraph 7 with: +In [concept.copymove], replace the postcondition in paragraph 7 with:

    @@ -16028,7 +11087,7 @@ by *this are released instead of transferred to rv. -- end

    911. I/O streams and move/swap semantic

    Section: 27.7.1 [input.streams], 27.7.2 [output.streams] Status: Open - Submitter: Alberto Ganesh Barbati Opened: 2008-09-29 Last modified: 2009-07-27

    + Submitter: Alberto Ganesh Barbati Opened: 2008-09-29 Last modified: 2009-10-20

    View all issues with Open status.

    Discussion:

    @@ -16169,6 +11228,17 @@ I've implemented this proposal and am living with it day to day.

    +

    [ +2009 Santa Cruz: +]

    + + +
    +Leave Open. Pablo expected to propose alternative wording which would rename +move construction, move assignment and swap, and may or may not make them +protected. This will impact issue 900. +
    +

    Proposed resolution:

    @@ -16269,8 +11339,8 @@ template <class charT, class traits>

    915. minmax with initializer_list should return pair of T, not pair of const T&

    -

    Section: 25.5.7 [alg.min.max] Status: Open - Submitter: Daniel Krügler Opened: 2008-10-04 Last modified: 2009-07-14

    +

    Section: 25.4.7 [alg.min.max] Status: Open + Submitter: Daniel Krügler Opened: 2008-10-04 Last modified: 2009-10-23

    View all other issues in [alg.min.max].

    View all issues with Open status.

    Discussion:

    @@ -16282,7 +11352,7 @@ this point:

    -25.5.7 [alg.min.max], before p.23 + p.24 + before p. 27 + p. 28 say that the return +25.4.7 [alg.min.max], before p.23 + p.24 + before p. 27 + p. 28 say that the return type of the minmax overloads with an initializer_list is pair<const T&, const T&>, which is inconsistent with the decision for the other min/max overloads which take @@ -16310,6 +11380,29 @@ Moved from Tentatively Ready to Open only because the wording needs to be tweaked for concepts removal.
    +

    [ +2009-08-18 Daniel adds: +]

    + + +
    +Recommend NAD since the proposed changes have already been performed +as part of editorial work of +N2914. +
    + +

    [ +2009-10 Santa Cruz: +]

    + + +
    +Can't find initializer_list form of minmax anymore, only variadic +version. Seems like we had an editing clash with concepts. Leave Open, +at least until editorial issues resolved. Bring this to Editor's +attention. +
    +

    Proposed resolution:

    @@ -16332,7 +11425,7 @@ minmax(initializer_list<T> t, Compare comp);

  • -In 25.5.7 [alg.min.max] change as indicated (Begin: Just before p.20): +In 25.4.7 [alg.min.max] change as indicated (Begin: Just before p.20): 

    template<classLessThanComparable T>
   requires CopyConstructible<T>
@@ -16377,269 +11470,13 @@ smallest value and y largest value in the initializer_list.
 
 
 
-
    
-
    916. Redundant move-assignment operator of pair should be removed
    
-
    Section: 20.3.3 [pairs] Status: Open
- Submitter: Daniel Krügler Opened: 2008-10-04  Last modified: 2009-07-18
    
-
    View other active issues in [pairs].
    
-
    View all other issues in [pairs].
    
-
    View all issues with Open status.
    
-
    Discussion:
    
-
    see also 917.
    
-
-
    
-The current WP provides the following assignment operators for pair
-in 20.3.3 [pairs]/1:
-
    
-
-
      
-
    1. 
-
      template<class U , class V>
-requires HasAssign<T1, const U&> && HasAssign<T2, const V&>
-pair& operator=(const pair<U , V>& p);
-
      
-
      2. 
-
    2. 
-
      requires MoveAssignable<T1> && MoveAssignable<T2> pair& operator=(pair&& p );
-
      
-
      3. 
-
    3. 
-
      template<class U , class V>
-requires HasAssign<T1, RvalueOf<U>::type> && HasAssign<T2, RvalueOf<V>::type>
-pair& operator=(pair<U , V>&& p);
-
      
-
      4. 
-
    
-
-
    
-It seems that the functionality of (2) is completely covered by (3), therefore
-(2) should be removed.
-
    
-
-
    [
-Batavia (2009-05):
-]
    
-
-
    
-
    
-Bill believes the extra assignment operators are necessary for resolving
-ambiguities, but that does not mean it needs to be part of the specification.
-
    
-
    
-Move to Open.
-We recommend this be looked at in the context of the ongoing work
-related to the pair templates.
-
    
-
    
-
-
    [
-2009-07 Frankfurt:
-]
    
-
-
-
    
-Leave this open pending the removal of concepts from the WD.
-
    
-
-
-
-
    Proposed resolution:
    
-
      
-
    1. 
-
      
-In 20.3.3 [pairs] p. 1, class pair and just before p. 13 remove the declaration:
-
      
-
-
      requires MoveAssignable<T1> && MoveAssignable<T2> pair& operator=(pair&& p );
-
      
-
      2. 
-
-
    2. 
-Remove p.13+p.14
-
      3. 
-
-
    
-
-
-
-
-
-
    
-
    917. Redundant move-assignment operator of tuple should be removed
    
-
    Section: 20.5.2.1 [tuple.cnstr] Status: Open
- Submitter: Daniel Krügler Opened: 2008-10-04  Last modified: 2009-07-18
    
-
    View other active issues in [tuple.cnstr].
    
-
    View all other issues in [tuple.cnstr].
    
-
    View all issues with Open status.
    
-
    Discussion:
    
-
    see also 916.
    
-
    
-N2770 (and thus now the WP) removed the
-non-template move-assignment operator from tuple's class definition,
-but the latter individual member description does still provide this
-operator. Is this (a) an oversight and can it (b) be solved as part of an
-editorial process?
-
    
-
-
    [
-Post Summit Daniel provided wording.
-]
    
-
-
-
    [
-Batavia (2009-05):
-]
    
-
-
    
-
    
-We believe that the proposed resolution's part 1 is editorial.
-
    
-
    
-Regarding part 2, we either remove the specification as proposed,
-or else add back the declaration to which the specification refers.
-Alisdair and Bill prefer the latter.
-It is not immediately obvious whether the function is intended to be present.
-
    
-
    
-We recommend that the Project Editor restore the missing declaration
-and that we keep part 2 of the issue alive.
-
    
-
    
-Move to Open.
-
    
-
    
-
-
    [
-2009-07 Frankfurt:
-]
    
-
-
-
    
-Leave this open pending the removal of concepts from the WD.
-
    
-
-
-
-
    Proposed resolution:
    
-
      
-
    1. 
-
      
-In 20.5.2 [tuple.tuple], class tuple just before member swap please
-change as indicated:
-
      
-
      [
-This fixes an editorial loss between N2798 to N2800
-]
      
-
-
      template <class... UTypes>
-requires HasAssign<Types, const UTypes&>...
-tuple& operator=(const pair<UTypes...>&);
-
-template <class... UTypes>
-requires HasAssign<Types, RvalueOf<UTypes>::type>...
-tuple& operator=(pair<UTypes...>&&);
-
      
-
      2. 
-
    2. 
-
      
-In 20.5.2.1 [tuple.cnstr], starting just before p. 11 please remove
-as indicated:
-
      
-
-
      requires MoveAssignable<Types>... tuple& operator=(tuple&& u);
-
      
-
      
-
      
--11- Effects: Move-assigns each element of u to the corresponding
-element of *this.
-
      
-
      
--12- Returns: *this.
-
      
-
      
-
      
-
      3. 
-
    
-
-
-
-
-
-
    
-
    919. (forward_)list specialized remove algorithms are over constrained
    
-
    Section: 23.3.3.5 [forwardlist.ops], 23.3.4.4 [list.ops] Status: Open
- Submitter: Daniel Krügler Opened: 2008-10-06  Last modified: 2009-07-21
    
-
    View other active issues in [forwardlist.ops].
    
-
    View all other issues in [forwardlist.ops].
    
-
    View all issues with Open status.
    
-
    Discussion:
    
-
    
-The signatures of forwardlist::remove and list::remove
-defined in 23.3.3.5 [forwardlist.ops] before 11 + 23.3.4.4 [list.ops] before 15:
-
    
-
-
    requires EqualityComparable<T> void remove(const T& value);
-
    
-
-
    
-are asymmetric to their predicate variants (which only require
-Predicate, not EquivalenceRelation) and with the free algorithm
-remove (which only require HasEqualTo). Also, nothing in the
-pre-concept WP
-N2723
-implies that EqualityComparable should
-be the intended requirement.
-
    
-
-
    [
-Batavia (2009-05):
-]
    
-
-
    
-
    
-We agree with the proposed resolution,
-but would like additional input from concepts experts.
-
    
-
    
-Move to Review.
-
    
-
    
-
-
    [
-2009-07-21 Alisdair adds:
-]
    
-
-
-
    
-Current rationale and wording for this issue is built around concepts. I
-suggest the issue reverts to Open status.  I believe there is enough of
-an issue to review after concepts are removed from the WP to re-examine
-the issue in Santa Cruz, rather than resolve as NAD Concepts.
-
    
-
-
-
    Proposed resolution:
    
-
      
-
    1. 
-
      
-Replace in 23.3.3.5 [forwardlist.ops] before 11 and in 23.3.4.4 [list.ops] before 15
-
      
-
-
      requires EqualityComparable<T> HasEqualTo<T, T> void remove(const T& value);
-
      
-
      2. 
-
    
-
-
-
-
-
-
 
    
 
    920. Ref-qualification support in the library
    
-
    Section: 20.7.15 [func.memfn] Status: Open
- Submitter: Bronek Kozicki Opened: 2008-10-06  Last modified: 2009-05-23
    
-
    View all issues with Open status.
    
+
    Section: 20.7.14 [func.memfn] Status: Ready
+ Submitter: Bronek Kozicki Opened: 2008-10-06  Last modified: 2009-10-23
    
+
    View all other issues in [func.memfn].
    
+
    View all issues with Ready status.
    
+
    Duplicate of: 1230
    
 
    Discussion:
    
 
    
 Daniel Krügler wrote:
@@ -16700,74 +11537,105 @@ Committee Draft has been issued.
    +

    [ +2009-10-10 Daniel updated wording to post-concepts. +]

    + + +
    +1230 has a similar proposed resolution +
    + +

    [ +2009-10 Santa Cruz: +]

    + + +
    +Move to Ready. +
    + +

    Proposed resolution:

    1. -In 20.7 [function.objects]/2, header <functional> synopsis, just after -the section "// 20.6.15, member function adaptors::" add the following -declarations to the existing list: +Change 20.7 [function.objects]/2, header +<functional> synopsis as follows:

      -
      template<Returnable R, class T, CopyConstructible... Args>
-  unspecified mem_fn(R (T::* pm)(Args...) &);
-template<Returnable R, class T, CopyConstructible... Args>
-  unspecified mem_fn(R (T::* pm)(Args...) const &);
-template<Returnable R, class T, CopyConstructible... Args>
-  unspecified mem_fn(R (T::* pm)(Args...) volatile &);
-template<Returnable R, class T, CopyConstructible... Args>
-  unspecified mem_fn(R (T::* pm)(Args...) const volatile &);
-template<Returnable R, class T, CopyConstructible... Args>
-  unspecified mem_fn(R (T::* pm)(Args...) &&);
-template<Returnable R, class T, CopyConstructible... Args>
-  unspecified mem_fn(R (T::* pm)(Args...) const &&);
-template<Returnable R, class T, CopyConstructible... Args>
-  unspecified mem_fn(R (T::* pm)(Args...) volatile &&);
-template<Returnable R, class T, CopyConstructible... Args>
-  unspecified mem_fn(R (T::* pm)(Args...) const volatile &&);
+
+
      // 20.7.14, member function adaptors:
+template<class R, class T> unspecified mem_fn(R T::*);
+
+template<class R, class T, class ...Args> unspecified mem_fn(R (T::*)(Args...));
+template<class R, class T, class ...Args> unspecified mem_fn(R (T::*)(Args...) const);
+template<class R, class T, class ...Args> unspecified mem_fn(R (T::*)(Args...) volatile);
+template<class R, class T, class ...Args> unspecified mem_fn(R (T::*)(Args...) const volatile);
+
+template<class R, class T, class ...Args> unspecified mem_fn(R (T::*)(Args...) &);
+template<class R, class T, class ...Args> unspecified mem_fn(R (T::*)(Args...) const &);
+template<class R, class T, class ...Args> unspecified mem_fn(R (T::*)(Args...) volatile &);
+template<class R, class T, class ...Args> unspecified mem_fn(R (T::*)(Args...) const volatile &);
+
+template<class R, class T, class ...Args> unspecified mem_fn(R (T::*)(Args...) &&);
+template<class R, class T, class ...Args> unspecified mem_fn(R (T::*)(Args...) const &&);
+template<class R, class T, class ...Args> unspecified mem_fn(R (T::*)(Args...) volatile &&);
+template<class R, class T, class ...Args> unspecified mem_fn(R (T::*)(Args...) const volatile &&);
      2. +

    2. -In 20.7.15 [func.memfn] add the following declarations to the existing -list: +Change the prototype list of 20.7.14 [func.memfn] as follows [NB: The +following text, most notably p.2 and p.3 which +discuss influence of the cv-qualification on the definition of the +base class's first template parameter remains +unchanged. ]:

      -
      template<Returnable R, class T, CopyConstructible... Args>
-  unspecified mem_fn(R (T::* pm)(Args...) &);
-template<Returnable R, class T, CopyConstructible... Args>
-  unspecified mem_fn(R (T::* pm)(Args...) const &);
-template<Returnable R, class T, CopyConstructible... Args>
-  unspecified mem_fn(R (T::* pm)(Args...) volatile &);
-template<Returnable R, class T, CopyConstructible... Args>
-  unspecified mem_fn(R (T::* pm)(Args...) const volatile &);
-template<Returnable R, class T, CopyConstructible... Args>
-  unspecified mem_fn(R (T::* pm)(Args...) &&);
-template<Returnable R, class T, CopyConstructible... Args>
-  unspecified mem_fn(R (T::* pm)(Args...) const &&);
-template<Returnable R, class T, CopyConstructible... Args>
-  unspecified mem_fn(R (T::* pm)(Args...) volatile &&);
-template<Returnable R, class T, CopyConstructible... Args>
-  unspecified mem_fn(R (T::* pm)(Args...) const volatile &&);
+
+
      template<class R, class T> unspecified mem_fn(R T::* pm);
+
+template<class R, class T, class ...Args> unspecified mem_fn(R (T::* pm)(Args...));
+template<class R, class T, class ...Args> unspecified mem_fn(R (T::* pm)(Args...) const);
+template<class R, class T, class ...Args> unspecified mem_fn(R (T::* pm)(Args...) volatile);
+template<class R, class T, class ...Args> unspecified mem_fn(R (T::* pm)(Args...) const volatile);
+
+template<class R, class T, class ...Args> unspecified mem_fn(R (T::* pm)(Args...) &);
+template<class R, class T, class ...Args> unspecified mem_fn(R (T::* pm)(Args...) const &);
+template<class R, class T, class ...Args> unspecified mem_fn(R (T::* pm)(Args...) volatile &);
+template<class R, class T, class ...Args> unspecified mem_fn(R (T::* pm)(Args...) const volatile &);
+
+template<class R, class T, class ...Args> unspecified mem_fn(R (T::* pm)(Args...) &&);
+template<class R, class T, class ...Args> unspecified mem_fn(R (T::* pm)(Args...) const &&);
+template<class R, class T, class ...Args> unspecified mem_fn(R (T::* pm)(Args...) volatile &&);
+template<class R, class T, class ...Args> unspecified mem_fn(R (T::* pm)(Args...) const volatile &&);
      3. -
    + +

  • -The following text, most notably p.2 and p.3 which discuss influence -of the cv-qualification on the definition of the base class's first template -parameter remains unchanged. +Remove 20.7.14 [func.memfn]/5:

    +
    +Remarks: Implementations may implement mem_fn as a set of +overloaded function templates. +
    +
    • + + +

    921. Rational Arithmetic should use template aliases

    -

    Section: 20.4.1 [ratio.ratio] Status: Review - Submitter: Pablo Halpern Opened: 2008-10-07 Last modified: 2009-07-21

    -

    View other active issues in [ratio.ratio].

    +

    Section: 20.4.1 [ratio.ratio] Status: Ready + Submitter: Pablo Halpern Opened: 2008-10-07 Last modified: 2009-10-21

    View all other issues in [ratio.ratio].

    -

    View all issues with Review status.

    +

    View all issues with Ready status.

    Discussion:

    The compile-time functions that operate on ratio<N,D> require the @@ -16865,6 +11733,16 @@ to allow time to improve the discussion if needed. See 1121 for a potentially incompatible proposal. +

    [ +2009-10 Santa Cruz: +]

    + + +
    +Move to Ready. +
    + +

    Proposed resolution:

    @@ -16982,377 +11860,13 @@ ToDuration::period>::type    , and [..] -
    -

    923. atomics with floating-point

    -

    Section: 29 [atomics] Status: Open - Submitter: Herb Sutter Opened: 2008-10-17 Last modified: 2009-05-01

    -

    View other active issues in [atomics].

    -

    View all other issues in [atomics].

    -

    View all issues with Open status.

    -

    Discussion:

    -

    -Right now, C++0x doesn't have atomic<float>. We're thinking of adding -the words to support it for TR2 (note: that would be slightly -post-C++0x). If we need it, we could probably add the words. -

    -

    -Proposed resolutions: Using atomic<FP>::compare_exchange (weak or -strong) should be either: -

    - -
      -
    1. -ill-formed, or -
      2. -
    2. -well-defined. -
      3. -
    - -

    -I propose Option 1 for C++0x for expediency. If someone wants to argue -for Option 2, they need to say what exactly they want compare_exchange -to mean in this case (IIRC, C++0x doesn't even assume IEEE 754). -

    - -

    [ -Summit: -]

    - - -
    -Move to open. Blocked until concepts for atomics are addressed. -
    - -

    [ -Post Summit Anthony adds: -]

    - - -
    -

    -Recommend NAD. C++0x does have std::atomic<float>, and both -compare_exchange_weak and compare_exchange_strong are well-defined in -this case. Maybe change the note in 29.6 [atomics.types.operations] paragraph 20 to: -

    - -
    -

    -[Note: The effect of the compare-and-exchange operations is -

    -
    if (!memcmp(object,expected,sizeof(*object)))
-    *object = desired;
-else
-    *expected = *object;
-
    - -

    -This may result in failed comparisons for values that compare equal if -the underlying type has padding bits or alternate representations of -the same value. -- end note] -

    -
    - -
    - - - -

    Proposed resolution:

    -

    -Change the note in 29.6 [atomics.types.operations] paragraph 20 to: -

    - -
    -

    -[Note: The effect of the compare-and-exchange operations is -

    -
    if (*object == *expected !memcmp(object,expected,sizeof(*object)))
-    *object = desired;
-else
-    *expected = *object;
-
    - -

    -This may result in failed comparisons for values that compare equal if -the underlying type has padding bits or alternate representations of -the same value. -- end note] -

    -
    - - - - - - -
    -

    924. structs with internal padding

    -

    Section: 29 [atomics] Status: Open - Submitter: Herb Sutter Opened: 2008-10-17 Last modified: 2009-03-22

    -

    View other active issues in [atomics].

    -

    View all other issues in [atomics].

    -

    View all issues with Open status.

    -

    Discussion:

    -

    -Right now, the compare_exchange_weak loop should rapidly converge on the -padding contents. But compare_exchange_strong will require a bit more -compiler work to ignore padding for comparison purposes. -

    -

    -Note that this isn't a problem for structs with no padding, and we do -already have one portable way to ensure that there is no padding that -covers the key use cases: Have elements be the same type. I suspect that -the greatest need is for a structure of two pointers, which has no -padding problem. I suspect the second need is a structure of a pointer -and some form of an integer. If that integer is intptr_t, there will be -no padding. -

    -

    -Related but separable issue: For unused bitfields, or other unused -fields for that matter, we should probably say it's the programmer's -responsibility to set them to zero or otherwise ensure they'll be -ignored by memcmp. -

    - -

    -Proposed resolutions: Using -atomic<struct-with-padding>::compare_exchange_strong should be either: -

    - -
      -
    1. -ill-formed, or -
      2. -
    2. -well-defined. -
      3. -
    - -

    -I propose Option 1 for C++0x for expediency, though I'm not sure how to -say it. I would be happy with Option 2, which I believe would mean that -compare_exchange_strong would be implemented to avoid comparing padding -bytes, or something equivalent such as always zeroing out padding when -loading/storing/comparing. (Either implementation might require compiler -support.) -

    - -

    [ -Summit: -]

    - - -
    -Move to open. Blocked until concepts for atomics are addressed. -
    - -

    [ -Post Summit Anthony adds: -]

    - - -
    -The resoultion of LWG 923 should resolve this issue as well. -
    - - - -

    Proposed resolution:

    -

    -

    - - - - - -
    -

    926. Sequentially consistent fences, relaxed operations and modification order

    -

    Section: 29.3 [atomics.order] Status: Open - Submitter: Anthony Williams Opened: 2008-10-19 Last modified: 2009-03-22

    -

    View all other issues in [atomics.order].

    -

    View all issues with Open status.

    -

    Discussion:

    -

    Addresses UK 313

    - -

    -There was an interesting issue raised over on comp.programming.threads -today regarding the following example -

    - -
    // Thread 1:
-x.store(1, memory_order_relaxed);           // SX
-atomic_thread_fence(memory_order_seq_cst);  // F1
-y.store(1, memory_order_relaxed);           // SY1
-atomic_thread_fence(memory_order_seq_cst);  // F2
-r1 = y.load(memory_order_relaxed);          // RY
-
-// Thread 2:
-y.store(0, memory_order_relaxed);          // SY2
-atomic_thread_fence(memory_order_seq_cst); // F3
-r2 = x.load(memory_order_relaxed);         // RX
-
    - -

    -is the outcome r1 == 0 and r2 == 0 possible? -

    -

    -I think the intent is that this is not possible, but I am not sure the -wording guarantees that. Here is my analysis: -

    -

    -Since all the fences are SC, there must be a total order between them. -F1 must be before F2 in that order since they are in -the same thread. Therefore F3 is either before F1, -between F1 and F2 or after F2. -

    -

    -If F3 is after F2, then we can apply 29.3 [atomics.order]p5 from -N2798: -

    - -
    -For atomic operations A and B on an atomic object -M, where A modifies M and B takes -its value, if there are memory_order_seq_cst fences X -and Y such that A is sequenced before X, -Y is sequenced before B, and X precedes -Y in S, then B observes either the effects of -A or a later modification of M in its modification -order. -
    - -

    -In this case, A is SX, B is RX, the -fence X is F2 and the fence Y is F3, -so RX must see 1. -

    -

    -If F3 is before F2, this doesn't apply, but -F3 can therefore be before or after F1. -

    -

    -If F3 is after F1, the same logic applies, but this -time the fence X is F1. Therefore again, RX -must see 1. -

    -

    -Finally we have the case that F3 is before F1 -in the SC ordering. There are now no guarantees about RX, and -RX can see r2==0. -

    -

    -We can apply 29.3 [atomics.order]p5 again. This time, -A is SY2, B is RY, X is -F3 and Y is F1. Thus RY must observe -the effects of SY2 or a later modification of y in its -modification order. -

    -

    -Since SY1 is sequenced before RY, RY must -observe the effects of SY1 or a later modification of -y in its modification order. -

    -

    -In order to ensure that RY sees (r1==1), we must see -that SY1 is later in the modification order of y than -SY2. -

    -

    -We're now skating on thin ice. Conceptually, SY2 happens-before -F3, F3 is SC-ordered before F1, F1 -happens-before SY1, so SY1 is later in the -modification order M of y, and RY must see -the result of SY1 (r1==1). However, I don't think the -words are clear on that. -

    - -

    [ -Post Summit Hans adds: -]

    - - -
    -

    -In my (Hans') view, our definition of fences will always be weaker than -what particular hardware will guarantee. Memory_order_seq_cst fences -inherently don't guarantee sequential consistency anyway, for good -reasons (e.g. because they can't enforce a total order on stores). - Hence I don't think the issue demonstrates a gross failure to achieve -what we intended to achieve. The example in question is a bit esoteric. - Hence, in my view, living with the status quo certainly wouldn't be a -disaster either. -

    -

    -In any case, we should probably add text along the lines of the -following between p5 and p6 in 29.3 [atomics.order]: -

    -
    -[Note: Memory_order_seq_cst only ensures sequential consistency for a -data-race-free program that uses exclusively memory_order_seq_cst -operations. Any use of weaker ordering will invalidate this guarantee -unless extreme care is used. In particular, memory_order_seq_cst fences -only ensure a total order for the fences themselves. They cannot, in -general, be used to restore sequential consistency for atomic operations -with weaker ordering specifications.] -
    - -

    -Also see thread beginning at c++std-lib-23271. -

    - -
    - -

    [ -Herve's correction: -]

    - -
    -

    -Minor point, and sorry for the knee jerk reaction: I admit to having -no knowledge of Memory_order_seq_cst, but my former boss (John Lakos) -has ingrained an automatic introspection on the use of "only". I -think you meant: -

    - -
    -[Note: Memory_order_seq_cst ensures sequential consistency only -for . . . . In particular, memory_order_seq_cst fences ensure a -total order only for . . . -
    -

    -Unless, of course, Memory_order_seq_cst really do nothing but ensure -sequential consistency for a data-race-free program that uses -exclusively memory_order_seq_cst operations. -

    -
    - - - -

    Proposed resolution:

    -

    -Add a new paragraph after 29.3 [atomics.order]p5 that says -

    - -
    -For atomic operations A and B on an atomic object -M, where A and B modify M, if there -are memory_order_seq_cst fences X and Y such -that A is sequenced before X, Y is sequenced -before B, and X precedes Y in S, -then B occurs later than A in the modifiction order of -M. -
    - - - - -

    929. Thread constructor

    -

    Section: 30.3.1.2 [thread.thread.constr] Status: Open - Submitter: Anthony Williams Opened: 2008-10-23 Last modified: 2009-07-18

    +

    Section: 30.3.1.2 [thread.thread.constr] Status: Review + Submitter: Anthony Williams Opened: 2008-10-23 Last modified: 2009-10-25

    View other active issues in [thread.thread.constr].

    View all other issues in [thread.thread.constr].

    -

    View all issues with Open status.

    +

    View all issues with Review status.

    Discussion:

    Addresses UK 323

    @@ -17418,7 +11932,7 @@ removes a move when passing in an lvalue.

    -This circumstance is very analogous to make_pair (20.3.3 [pairs]) +This circumstance is very analogous to make_pair (20.3.4 [pairs]) where we started with passing by const reference, changed to pass by value to get pointer decay, and then changed to pass by rvalue reference, but modified with decay<T> to retain the pass-by-value behavior. If we were to @@ -17495,9 +12009,26 @@ In Frankfurt there is no consensus for removing the variadic constructor.

    +

    [ +2009-10 Santa Cruz: +]

    -

    Proposed resolution:

    +
    +We want to move forward with this issue. If we later take it out via 1176 +then that's ok too. Needs small group to improve wording. +
    + +

    [ +2009-10 Santa Cruz: +]

    + + +
    +

    +Stefanus provided revised wording. Moved to Review Here is the original wording: +

    +

    Modify the class definition of std::thread in 30.3.1 [thread.thread.class] to remove the following signature: @@ -17547,356 +12078,63 @@ invocation of f g.

    - - - - - -
    -

    930. Access to std::array data as built-in array type

    -

    Section: 23.3.1 [array] Status: Review - Submitter: Niels Dekker Opened: 2008-11-17 Last modified: 2009-07-31

    -

    View other active issues in [array].

    -

    View all other issues in [array].

    -

    View all issues with Review status.

    -

    Discussion:

    - -

    -The Working Draft (N2798) allows access to the elements of -std::array by its data() member function: -

    - -
    - -
    23.2.1.4 array::data [array.data]
    -
     T *data();
- const T *data() const;
-
    -
    1. - Returns: elems. -
    - -

    -Unfortunately, the result of std::array::data() cannot be bound -to a reference to a built-in array of the type of array::elems. -And std::array provides no other way to get a reference to -array::elems. -This hampers the use of std::array, for example when trying to -pass its data to a C style API function: -

    - -
     // Some C style API function. 
- void set_path( char (*)[MAX_PATH] );
-
- std::array<char,MAX_PATH> path;
- set_path( path.data() );  // error
- set_path( &(path.data()) );  // error
-
    - -

    -Another example, trying to pass the array data to an instance of another -C++ class: -

    - -
     // Represents a 3-D point in space.
- class three_d_point {
- public:
-   explicit three_d_point(const double (&)[3]); 
- };
-
- const std::array<double,3> coordinates = { 0, 1, 2 };
- three_d_point point1( coordinates.data() );  // error.
- three_d_point point2( *(coordinates.data()) );  // error.
-
    - -

    -A user might be tempted to use std::array::elems instead, but -doing so isn't recommended, because std::array::elems is "for -exposition only". Note that Boost.Array users might already use -boost::array::elems, as its documentation doesn't explicitly -state that boost::array::elems is for exposition only: -http://www.boost.org/doc/libs/1_36_0/doc/html/boost/array.html -

    -

    -I can think of three options to solve this issue: -

    -
    1. -Remove the words "exposition only" from the definition of -std::array::elems, as well as the note saying that "elems is -shown for exposition only." -
    2. -Change the signature of std::array::data(), so that it would -return a reference to the built-in array, instead of a pointer to its -first element. -
    3. -Add extra member functions, returning a reference to the built-in array. -
    -

    -Lawrence Crowl wrote me that it might be better to leave -std::array::elems "for exposition only", to allow alternate -representations to allocate the array data dynamically. This might be -of interest to the embedded community, having to deal with very limited -stack sizes. -

    -

    -The second option, changing the return type of -std::array::data(), would break backward compatible to current -Boost and TR1 implementations, as well as to the other contiguous -container (vector and string) in a very subtle way. -For example, the following call to std::swap currently swap two -locally declared pointers (data1, data2), for any container -type T that has a data() member function. When -std::array::data() is changed to return a reference, the -std::swap call may swap the container elements instead. -

    - -
     template <typename T>
- void func(T& container1, T& container2)
- {
-   // Are data1 and data2 pointers or references?
-   auto data1 = container1.data();
-   auto data2 = container2.data();
-
-   // Will this swap two local pointers, or all container elements?
-   std::swap(data1, data2);
- }
-
    - -

    -The following concept is currently satisfied by all contiguous -containers, but it no longer is for std::array, when -array::data() -is changed to return a reference (tested on ConceptGCC Alpha 7): -

    - -
     auto concept ContiguousContainerConcept<typename T>
- {
-   typename value_type = typename T::value_type;
-   const value_type * T::data() const;
- }
-
    - -

    -Still it's worth considering having std::array::data() return a -reference, because it might be the most intuitive option, from a user's -point of view. Nicolai Josuttis (who wrote boost::array) -mailed me that he very much prefers this option. -

    -

    -Note that for this option, the definition of data() would also -need to be revised for zero-sized arrays, as its return type cannot be a -reference to a zero-sized built-in array. Regarding zero-sized array, -data() could throw an exception. Or there could be a partial -specialization of std::array where data() returns -T* or gets removed. -

    -

    -Personally I prefer the third option, adding a new member function to -std::array, overloaded for const and non-const access, -returning a reference to the built-in array, to avoid those compatible -issues. I'd propose naming the function std::array::c_array(), -which sounds intuitive to me. Note that boost::array already -has a c_array() member, returning a pointer, but Nicolai told -me that this one is only there for historical reasons. (Otherwise a name -like std::array::native_array() or -std::array::builtin_array() would also be fine with me.) -According to my proposed resolution, a zero-sized std::array does not need -to have c_array(), while it is still required to have -data() functions. -

    - -

    [ -Post Summit: -]

    - - -
    - -

    -Alisdair: Don't like p4 suggesting implementation-defined behaviour. -

    -

    -Walter: What about an explicit conversion operator, instead of adding -the new member function? -

    -

    -Alisdair: Noodling about: -

    -
    template<size_t N, ValueType T>
-struct array
-{
-  T elems[N];
-
-// fantasy code starts here
-
-// crazy decltype version for grins only
-//requires True<(N>0)>
-//explict operator decltype(elems) & () { return elems; }
-
-// conversion to lvalue ref
-requires True<(N>0)>
-explict operator T(&)[N] () & { return elems; }
-
-// conversion to const lvalue ref
-requires True<(N>0)>
-explict operator const T(&)[N] () const & { return elems; }
-
-// conversion to rvalue ref using ref qualifiers
-requires True<(N>0)>
-explict operator T(&&)[N] () && { return elems; }
-
-// fantasy code ends here
-
-explicit operator bool() { return true; }
-};
-
    - -

    -This seems legal but odd. Jason Merrill says currently a CWG issue 613 -on the non-static data member that fixes the error that current G++ -gives for the non-explicit, non-conceptualized version of this. Verdict -from human compiler: seems legal. -

    -

    -Some grumbling about zero-sized arrays being allowed and supported. -

    -

    -Walter: Would this address the issue? Are we inclined to go this route? -

    -

    -Alan: What would usage look like? -

    -
    // 3-d point in space
-struct three_d_point
-{
-  explicit three_d_point(const double (&)[3]);
-};
-
-void sink(double*);
-
-const std::array<double, 3> coordinates = { 0, 1, 2 };
-three_d_point point1( coordinates.data() ); //error
-three_d_point point2( *(coordinates.data()) ); // error
-three_d_point point3( coordinates ); // yay!
-
-sink(cooridinates); // error, no conversion
-
    - -

    -Recommended Open with new wording. Take the required clause and add the -explicit conversion operators, not have a typedef. At issue still is use -decltype or use T[N]. In favour of using T[N], even though use of -decltype is specially clever. -

    - -
    - -

    [ -Post Summit, further discussion in the thread starting with c++std-lib-23215. -]

    - - -

    [ -2009-07 post-Frankfurt (Saturday afternoon group): -]

    - - -
    -

    -The idea to resolve the issue by adding explicit conversion operators -was abandoned, because it would be inconvenient to use, especially when -passing the array to a template function, as mentioned by Daniel. So we -reconsidered the original proposed resolution, which appeared -acceptable, except for its proposed changes to 23.3.1.6 [array.zero], which -allowed c_array_type and c_array() to be absent for a zero-sized array. -Alisdair argued that such wording would disallow certain generic use -cases. New wording for 23.3.1.6 [array.zero] was agreed upon (Howard: and -is reflected in the proposed resolution). -

    -

    -Move to Review -

    -
    - -

    [ -2009-07-31 Alisdair adds: -]

    - - -
    -

    -I will be unhappy voting the proposed resolution for 930 past review -until we have implementation experience with reference qualifiers. -Specifically, I want to understand the impact of the missing overload -for const && (if any.) -

    - -

    -If we think the issue is important enough it might be worthwhile -stripping the ref qualifiers for easy progress next meeting, and opening -yet another issue to put them back with experience. -

    - -

    -Recommend deferring any decision on splitting the issue until we get LWG -feedback next meeting - I may be the lone dissenting voice if others are -prepared to proceed without it. -

    Proposed resolution:

    -Add to the template definition of array, 23.3.1 [array]/3: +Modify the class definition of std::thread in 30.3.1 [thread.thread.class] to remove the +following signature:

    -
    -
    
-typedef T c_array_type[N];
-c_array_type & c_array() &;
-c_array_type && c_array() &&;
-const c_array_type & c_array() const &;
-
-
    -
    +
    template<class F> explicit thread(F f);
+template<class F, class ... Args> explicit thread(F&& f, Args&& ... args);
+

    -Add the following subsection to 23.3.1 [array], after 23.3.1.4 [array.data]: +Modify 30.3.1.2 [thread.thread.constr] to replace the constructors prior to paragraph 4 with +the single constructor as above. Replace paragraph 4 - 6 with the +following:

    -
    -
    23.2.1.5 array::c_array [array.c_array]
    - 
    
-c_array_type & c_array() &;
-c_array_type && c_array() &&;
-const c_array_type & c_array() const &;
-

    -Returns: elems. +-4- Requires: F and each Ti in Args +shall be CopyConstructible if an lvalue and +otherwise MoveConstructible. INVOKE(f, w1, w2, +..., wN) (20.7.2 [func.require]) shall be a valid expression +for some values w1, w2, ... , wN, where N == +sizeof...(Args).

    -
    - -
    - -

    -Change Zero sized arrays 23.3.1.6 [array.zero]: +-5- Effects: Constructs an object of type thread and executes +INVOKE(f, t1, t2, ..., tN) in a new thread of execution, where +t1, t2, ..., tN are the values in args.... +Given a function as follows: +Any return +value from f is ignored. If f terminates with an +uncaught exception, std::terminate() shall be called.

    -
    - -

    -2- ...

    +
    
+template<typename T> typename decay<T>::type decay_copy(T&& v)
+    { return std::forward<T>(v); }
+

    -The type c_array_type is unspecified for a zero-sized array. +The new thread of execution executes INVOKE(decay_copy(f), +decay_copy(args)...) with the calls to decay_copy() being evaluated in +the constructing thread. Any return value from this invocation is +ignored. [Note: this implies any exceptions not thrown from the +invocation of the copy of f will be thrown in the constructing thread, +not the new thread. — end note].

    --3- The effect of calling c_array(), front(), or -back() for a zero-sized array is implementation defined. +-6- Synchronization: The invocation of the constructor happens before the +invocation of copy of f.

    @@ -17907,17 +12145,17 @@ The type c_array_type is unspecified for a zero-sized array.

    932. unique_ptr(pointer p) for pointer deleter types

    -

    Section: 20.8.9.2.1 [unique.ptr.single.ctor] Status: Open - Submitter: Howard Hinnant Opened: 2008-11-26 Last modified: 2009-07-27

    +

    Section: 20.8.14.2.1 [unique.ptr.single.ctor] Status: Ready + Submitter: Howard Hinnant Opened: 2008-11-26 Last modified: 2009-10-22

    View other active issues in [unique.ptr.single.ctor].

    View all other issues in [unique.ptr.single.ctor].

    -

    View all issues with Open status.

    +

    View all issues with Ready status.

    Discussion:

    Addresses US 79

    -20.8.9.2.1 [unique.ptr.single.ctor]/5 no longer requires for D +20.8.14.2.1 [unique.ptr.single.ctor]/5 no longer requires for D not to be a pointer type. I believe this restriction was accidently removed when we relaxed the completeness reuqirements on T. The restriction needs to be put back in. Otherwise we have a run time failure that could @@ -18016,11 +12254,47 @@ the implementation from the Requires paragraph to a Remarks paragraph.

    +

    [ +2009-08-17 Daniel adds: +]

    + + +
    +

    +It is insufficient to require a diagnostic. This doesn't imply an +ill-formed program +as of 1.3.3 [defns.diagnostic] (a typical alternative would be a compiler +warning), but +exactly that seems to be the intend. I suggest to use the following +remark instead: +

    + +
    +Remarks: The program shall be ill-formed if this constructor is +instantiated when D is a pointer type or reference type. +
    + +

    +Via the general standard rules of 1.4 [intro.compliance] the "diagnostic +required" is implied. +

    + +
    + +

    [ +2009-10 Santa Cruz: +]

    + + +
    +Moved to Ready. +
    +

    Proposed resolution:

    -Change the description of the default constructor in 20.8.9.2.1 [unique.ptr.single.ctor]: +Change the description of the default constructor in 20.8.14.2.1 [unique.ptr.single.ctor]: 

    unique_ptr();
@@ -18032,21 +12306,27 @@ shall not throw an exception. D shall
 not be a reference type or pointer type (diagnostic required).
 
    
 
    ...
    
-Remarks: A diagnostic shall be emitted if this constructor is instantiated
-when D is a pointer type or reference type.
+
    
+Remarks: The program shall be ill-formed if this constructor is
+instantiated when D is a pointer type or reference type.
+
+

    -Add after 20.8.9.2.1 [unique.ptr.single.ctor]/8: +Add after 20.8.14.2.1 [unique.ptr.single.ctor]/8: 

    unique_ptr(pointer p);

    ...

    -Remarks: A diagnostic shall be emitted if this constructor is instantiated -when D is a pointer type or reference type. +

    +Remarks: The program shall be ill-formed if this constructor is +instantiated when D is a pointer type or reference type. + +

    @@ -18054,475 +12334,12 @@ when D is a pointer type or reference type. -
    -

    933. Unique_ptr defect

    -

    Section: 20.8.9.2.5 [unique.ptr.single.modifiers] Status: Open - Submitter: Alisdair Meredith Opened: 2008-11-27 Last modified: 2009-05-23

    -

    View all other issues in [unique.ptr.single.modifiers].

    -

    View all issues with Open status.

    -

    Discussion:

    -

    -If we are supporting stateful deleters, we need an overload for -reset that -takes a deleter as well. -

    - -
    void reset( pointer p, deleter_type d);
-
    - -

    -We probably need two overloads to support move-only deleters, and -this -sounds uncomfortably like the two constructors I have been ignoring -for -now... -

    - -

    [ -Batavia (2009-05): -]

    - -
    -

    -Howard comments that we have the functionality via move-assigment. -

    -

    -Move to Open. -

    -
    - - -

    Proposed resolution:

    -

    -

    - - - - - -
    -

    934. duration is missing operator%

    -

    Section: 20.9.3 [time.duration] Status: Ready - Submitter: Terry Golubiewski Opened: 2008-11-30 Last modified: 2009-07-27

    -

    View other active issues in [time.duration].

    -

    View all other issues in [time.duration].

    -

    View all issues with Ready status.

    -

    Discussion:

    - -

    Addresses US 81

    - -

    -duration is missing operator%. This operator is convenient -for computing where in a time frame a given duration lies. A -motivating example is converting a duration into a "broken-down" -time duration such as hours::minutes::seconds: -

    - -
    class ClockTime
-{
-    typedef std::chrono::hours hours;
-    typedef std::chrono::minutes minutes;
-    typedef std::chrono::seconds seconds;
-public:
-    hours hours_;
-    minutes minutes_;
-    seconds seconds_;
-
-    template <class Rep, class Period>
-      explicit ClockTime(const std::chrono::duration<Rep, Period>& d)
-        : hours_  (std::chrono::duration_cast<hours>  (d)),
-          minutes_(std::chrono::duration_cast<minutes>(d % hours(1))),
-          seconds_(std::chrono::duration_cast<seconds>(d % minutes(1)))
-          {}
-};
-
    - -

    [ -Summit: -]

    - - -
    -Agree except that there is a typo in the proposed resolution. The member -operators should be operator%=. -
    - -

    [ -Batavia (2009-05): -]

    - -
    -We agree with the proposed resolution. -Move to Tentatively Ready. -
    - -

    [ -2009-07 Frankfurt -]

    - - -
    -Moved from Tentatively Ready to Open only because the wording needs to be -improved for enable_if type constraining, possibly following Robert's -formula. -
    - -

    [ -2009-07 Frankfurt: -]

    - - -
    -

    -Howard to open a separate issue (1177) to handle the removal of member -functions from overload sets, provide wording, and possibly demonstrate -how this can be implemented using enable_if (see 947). -

    -

    -Move to Ready. -

    -
    - - - -

    Proposed resolution:

    -

    -Add to the synopsis in 20.9 [time]: -

    - -
    template <class Rep1, class Period, class Rep2>
-  duration<typename common_type<Rep1, Rep2>::type, Period>
-  operator%(const duration<Rep1, Period>& d, const Rep2& s);
-template <class Rep1, class Period1, class Rep2, class Period2>
-  typename common_type<duration<Rep1, Period1>, duration<Rep2, Period2>>::type
-  operator%(const duration<Rep1, Period1>& lhs, const duration<Rep2, Period2>& rhs);
-
    - -

    -Add to the synopsis of duration in 20.9.3 [time.duration]: -

    - -
    template <class Rep, class Period = ratio<1>>
-class duration {
-public:
-  ...
-  duration& operator%=(const rep& rhs);
-  duration& operator%=(const duration& d);
-  ...
-};
-
    - -

    -Add to 20.9.3.3 [time.duration.arithmetic]: -

    - -
    -
    duration& operator%=(const rep& rhs);
-
    -
    -

    -Effects: rep_ %= rhs. -

    -

    -Returns: *this. -

    -
    - -
    duration& operator%=(const duration& d);
-
    -
    -

    -Effects: rep_ %= d.count(). -

    -

    -Returns: *this. -

    -
    -
    - -

    -Add to 20.9.3.5 [time.duration.nonmember]: -

    - -
    - -
    template <class Rep1, class Period, class Rep2>
-  duration<typename common_type<Rep1, Rep2>::type, Period>
-  operator%(const duration<Rep1, Period>& d, const Rep2& s);
-
    -
    -

    -Requires: Rep2 shall be implicitly convertible to CR(Rep1, Rep2) and -Rep2 shall not be an instantiation of duration. Diagnostic required. -

    -

    -Returns: duration<CR, Period>(d) %= s. -

    -
    - -
    template <class Rep1, class Period1, class Rep2, class Period2>
-  typename common_type<duration<Rep1, Period1>, duration<Rep2, Period2>>::type
-  operator%(const duration<Rep1, Period1>& lhs, const duration<Rep2, Period2>& rhs);
-
    -
    -

    -Returns: common_type<duration<Rep1, Period1>, duration<Rep2, Period2>>::type(lhs) %= rhs. -

    -
    - -
    - - - - - - -
    -

    935. clock error handling needs to be specified

    -

    Section: 20.9.5 [time.clock] Status: Open - Submitter: Beman Dawes Opened: 2008-11-24 Last modified: 2009-05-23

    -

    View all issues with Open status.

    -

    Discussion:

    -

    -Each of the three clocks specified in Clocks 20.9.5 [time.clock] -provides the member function: -

    - -
    static time_point now();
-
    - -

    -The semantics specified by Clock requirements 20.9.1 [time.clock.req] -make no mention of error handling. Thus the function may throw bad_alloc -or an implementation-defined exception (17.6.4.10 [res.on.exception.handling] -paragraph 4). -

    - -

    -Some implementations of these functions on POSIX, Windows, and -presumably on other operating systems, may fail in ways only detectable -at runtime. Some failures on Windows are due to supporting chipset -errata and can even occur after successful calls to a clock's now() -function. -

    - -

    -These functions are used in cases where exceptions are not appropriate -or where the specifics of the exception or cause of error need to be -available to the user. See -N2828, -Library Support for hybrid error -handling (Rev 1), for more specific discussion of use cases. Thus some change in -the interface of now is required. -

    - -

    -The proposed resolution has been implemented in the Boost version of the -chrono library. No problems were encountered. -

    - -

    [ -Batavia (2009-05): -]

    - -
    -

    -We recommend this issue be deferred until the next Committee Draft -has been issued and the prerequisite paper has been accepted. -

    -

    -Move to Open. -

    -
    - - -

    Proposed resolution:

    -

    -Accept the proposed wording of -N2828, -Library Support for hybrid error handling (Rev 1). -

    - -

    -Change Clock requirements 20.9.1 [time.clock.req] as indicated: -

    - -
    -

    --2- In Table 55 C1 and C2 denote clock types. t1 and -t2 are values returned by C1::now() where the call -returning t1 happens before (1.10) the call returning t2 and -both of these calls happen before C1::time_point::max(). -ec denotes an object of type error_code -(19.5.2.2 [syserr.errcode.overview]). -

    - - - - - - - - - - - - - - - - - - - - - - - - -
    Table 55 -- Clock requirements
    ExpressionReturn typeOperational semantics
    .........
    C1::now()C1::time_pointReturns a time_point object representing the current point in time. -
    C1::now(ec)C1::time_pointReturns a time_point object representing the current point in time. -
    -
    - -

    -Change Class system_clock 20.9.5.1 [time.clock.system] as indicated: -

    - -
    static time_point now(error_code& ec=throws());
-
    - -

    -Change Class monotonic_clock 20.9.5.2 [time.clock.monotonic] as indicated: -

    - -
    static time_point now(error_code& ec=throws());
-
    - -

    -Change Class high_resolution_clock 20.9.5.3 [time.clock.hires] as indicated: -

    - -
    static time_point now(error_code& ec=throws());
-
    - - - - - - -
    -

    936. Mutex type overspecified

    -

    Section: 30.4.1 [thread.mutex.requirements] Status: Open - Submitter: Pete Becker Opened: 2008-12-05 Last modified: 2009-03-22

    -

    View other active issues in [thread.mutex.requirements].

    -

    View all other issues in [thread.mutex.requirements].

    -

    View all issues with Open status.

    -

    Discussion:

    -

    -30.4.1 [thread.mutex.requirements] describes the requirements for a type to be -a "Mutex type". A Mutex type can be used as the template argument for -the Lock type that's passed to condition_variable_any::wait (although -Lock seems like the wrong name here, since Lock is given a different -formal meaning in 30.4.3 [thread.lock]) and, although the WD doesn't quite say -so, as the template argument for lock_guard and unique_lock. -

    - -

    -The requirements for a Mutex type include: -

    - -
      -
    • -m.lock() shall be well-formed and have [described] semantics, including a return type of void. -
      • -
    • -m.try_lock() shall be well-formed and have [described] semantics, including a return type of bool. -
      • -
    • -m.unlock() shall be well-formed and have [described] semantics, including a return type of void. -
      • -
    - -

    -Also, a Mutex type "shall not be copyable nor movable". -

    - -

    -The latter requirement seems completely irrelevant, and the three -requirements on return types are tighter than they need to be. For -example, there's no reason that lock_guard can't be instantiated with a -type that's copyable. The rule is, in fact, that lock_guard, etc. won't -try to copy objects of that type. That's a constraint on locks, not on -mutexes. Similarly, the requirements for void return types are -unnecessary; the rule is, in fact, that lock_guard, etc. won't use any -returned value. And with the return type of bool, the requirement should -be that the return type is convertible to bool. -

    - -

    [ -Summit: -]

    - - -
    -

    -Move to open. Related to conceptualization and should probably be tackled as part of that. -

    -
      -
    • -The intention is not only to place a constraint on what types such as -lock_guard may do with mutex types, but on what any code, including user -code, may do with mutex types. Thus the constraints as they are apply to -the mutex types themselves, not the current users of mutex types in the -standard. -
      • -
    • -This is a low priority issue; the wording as it is may be overly -restrictive but this may not be a real issue. -
      • -
    -
    - -

    [ -Post Summit Anthony adds: -]

    - - -
    -

    -Section 30.4.1 [thread.mutex.requirements] conflates the -requirements on a generic Mutex type (including user-supplied mutexes) -with the requirements placed on the standard-supplied mutex types in an -attempt to group everything together and save space. -

    -

    -When applying concepts to chapter 30, I suggest that the concepts -Lockable and TimedLockable embody the requirements for -*use* of a mutex type as required by -unique_lock/lock_guard/condition_variable_any. These should be -relaxed as Pete describes in the issue. The existing words in 30.4.1 [thread.mutex.requirements] are requirements on all of -std::mutex, std::timed_mutex, -std::recursive_mutex and std::recursive_timed_mutex, -and should be rephrased as such. -

    -
    - - - -

    Proposed resolution:

    -

    -

    - - - - -

    939. Problem with std::identity and reference-to-temporaries

    -

    Section: 20.7.6 [identity.operation] Status: Open - Submitter: Alisdair Meredith Opened: 2008-12-11 Last modified: 2009-07-30

    -

    View all issues with Open status.

    +

    Section: 20.3.3 [forward] Status: Ready + Submitter: Alisdair Meredith Opened: 2008-12-11 Last modified: 2009-10-29

    +

    View all other issues in [forward].

    +

    View all issues with Ready status.

    Discussion:

    std::identity takes an argument of type T const & @@ -18644,7 +12461,7 @@ forward(U&& t)

    [ -The above code assumes acceptance of 1120 for the definition of +The above code assumes acceptance of 1120 for the definition of remove_all. This is just to make the syntax a little more palatable. Without this trait the above is still very implementable. ]

    @@ -18658,45 +12475,44 @@ Paper with rationale is on the way ... really, I promise this time! ;-)

    [ -2009-07-30 Daniel adds: See 823 for an alternative resolution. +2009-07-30 Daniel adds: See 823 for an alternative resolution. ]

    +

    [ +2009-10 Santa Cruz: +]

    + + +
    +Move to Ready. Howard will update proposed wording to reflect current draft. +
    + +

    Proposed resolution:

    -Strike 20.2.1 [concept.transform] p3: +Strike from 20.3 [utility]:

    -
    --4- Note: concept form of the identity type metafunction (20.7.6). -
    - -

    -Strike from 20.7 [function.objects] p2: -

    - -
    // 20.7.6, identity operation:
-template <IdentityOf T> struct identity;
+
    template <class T> struct identity;
 
    
 
 
    
-Remove 20.7.6 [identity.operation] (whole subclause):
+Remove from 20.3.3 [forward]:
 
    
 
 
    
-
    template <IdentityOf T> struct identity {
+
    template <class T> struct identity {
   typedef T type;
 
-  requires ReferentType<T>
-     const T& operator()(const T& x) const;
+  const T& operator()(const T& x) const;
 };
 
-requires ReferentType<T>
-  const T& operator()(const T& x) const;
+const T& operator()(const T& x) const;
 
    
 
    
--1-  Returns: x
+-2-  Returns: x
 
    
 
    
 
@@ -18707,17 +12523,17 @@ Remove 20.7.6 [identity.operation] (whole subclause):
 
 
    
 
    940. std::distance
    
-
    Section: 24.4 [iterator.operations] Status: Open
- Submitter: Thomas Opened: 2008-12-14  Last modified: 2009-07-18
    
+
    Section: 24.4.4 [iterator.operations] Status: Ready
+ Submitter: Thomas Opened: 2008-12-14  Last modified: 2009-10-22
    
 
    View other active issues in [iterator.operations].
    
 
    View all other issues in [iterator.operations].
    
-
    View all issues with Open status.
    
+
    View all issues with Ready status.
    
 
    Discussion:
    
 
 
    Addresses UK 270
    
 
 
    
-Regarding the std::distance - function, 24.4 [iterator.operations]
+Regarding the std::distance - function, 24.4.4 [iterator.operations]
 / 4 says:
 
    
 
    
@@ -18726,7 +12542,7 @@ number of increments or decrements needed to get from first to last.
 
    
 
    
 This sentence is completely silent about the sign of the return value.
-24.4 [iterator.operations] / 1 gives more information about the
+24.4.4 [iterator.operations] / 1 gives more information about the
 underlying operations, but
 again no inferences about the sign can be made.
 Strictly speaking, that is taking that sentence literally, I think this
@@ -18770,7 +12586,7 @@ contradiction to that resolution:
 
    
 Referring to
 N2798,
-24.4 [iterator.operations]/ p.4 says:
+24.4.4 [iterator.operations]/ p.4 says:
 
    
 
 
    
@@ -18787,7 +12603,7 @@ IMO the part " or decrements" is in contradiction to p. 5 which says
 
    
 
 
    
-because "reachable" is defined in 24.2 [iterator.concepts]/7 as
+because "reachable" is defined in X [iterator.concepts]/7 as
 
    
 
 
    
@@ -18801,7 +12617,7 @@ Here is wording that would be consistent with this definition of "reachable":
 
    
 
 
    
-Change 24.4 [iterator.operations] p4 as follows:
+Change 24.4.4 [iterator.operations] p4 as follows:
 
    
 
 
    
@@ -18859,228 +12675,72 @@ tweaked for concepts removal.
 Leave Open pending arrival of a post-Concepts WD.
 
    
 
+
    [
+2009-10-14 Daniel provided de-conceptified wording.
+]
    
 
 
-
    Proposed resolution:
    
-
    
-Change 24.4 [iterator.operations]:
-
    
-
-
    
-
    template <InputIterator Iter>
-  Iter::difference_type
-  distance(Iter first, Iter last);
-template <RandomAccessIterator Iter>
-  Iter::difference_type distance(Iter first, Iter last);
-
    
-
-
    
-
    
--4- Effects: Returns the number of increments or decrements
-needed to get from first to last.
-
    
-
    
--5- Requires: last shall be reachable from first.
-
    
-
    
-
-
    template <RandomAccessIterator Iter>
-  Iter::difference_type distance(Iter first, Iter last);
-
    
-
-
    
-
    
--6- Effects: Returns the number of increments or decrements
-needed to get from first to last.
-
    
-
    
--7- Requires: last shall be reachable from first
-or first shall be reachable from last.
-
    
-
    
-
-
-
    
-
-
-
-
-
-
-
    
-
    944. atomic<bool> derive from atomic_bool?
    
-
    Section: 29.5.3 [atomics.types.generic] Status: Open
- Submitter: Holger Grund Opened: 2008-12-19  Last modified: 2009-03-22
    
-
    View all other issues in [atomics.types.generic].
    
-
    View all issues with Open status.
    
-
    Discussion:
    
-
    
-I think it's fairly obvious that atomic<bool> is supposed to be derived
-from atomic_bool (and otherwise follow the atomic<integral> interface),
-though I think the current wording doesn't support this. I raised this
-point along with atomic<floating-point> privately with Herb and I seem
-to recall it came up in the resulting discussion on this list. However,
-I don't see anything on the current libs issue list mentioning this
-problem.
-
    
-
-
    
-29.5.3 [atomics.types.generic]/3 reads
-
    
-
-
    
-There are full specializations over the integral types on the atomic
-class template. For each integral type integral in the second column of
-table 121 or table 122, the specialization atomic<integral> shall be
-publicly derived from the corresponding atomic integral type in the
-first column of the table. These specializations shall have trivial
-default constructors and trivial destructors.
-
    
-
-
    
-Table 121 does not include (atomic_bool, bool),
-so that this should probably be mentioned explicitly in the quoted paragraph.
-
    
-
 
    [
-Summit:
+2009-10 Santa Cruz:
 ]
    
 
 
 
    
-Move to open. Lawrence will draft a proposed resolution. Also, ask
-Howard to fix the title.
+Move to Ready, replacing the Effects clause in the proposed wording with
+"If InputIterator meets the requirements of random access iterator then
+returns (last - first), otherwise returns the number of increments
+needed to get from first to list.".
 
    
 
-
    [
-Post Summit Anthony provided proposed wording.
-]
    
-
 
 
 
    Proposed resolution:
    
+
      
+
    1. 
 
      
-Replace paragraph 3 in 29.5.3 [atomics.types.generic] with
+Change 24.2.5 [random.access.iterators], Table 105 as indicated [This change is not
+essential but it simplifies the specification] for the row with
+expression "b - a"
+and the column Operational semantics:
 
      
 
-
      
--3- There are full specializations over the integral types on the atomic
-class template. For each integral type integral in the second column of
-table 121 or table 122, the specialization atomic<integral> shall be
-publicly derived from the corresponding atomic integral type in the first
-column of the table.
-In addition, the specialization atomic<bool>
-shall be publicly derived from atomic_bool.
-These specializations shall have trivial default
-constructors and trivial destructors.
-
      
-
-
-
-
-
-
      
-
      947. duration arithmetic: contradictory requirements
      
-
      Section: 20.9.3.5 [time.duration.nonmember] Status: Open
- Submitter: Pete Becker Opened: 2008-12-20  Last modified: 2009-07-27
      
-
      View all other issues in [time.duration.nonmember].
      
-
      View all issues with Open status.
      
-
      Discussion:
      
-
      
-In 20.9.3.5 [time.duration.nonmember], paragraph 8 says that calling
-dur / rep
-when rep is an instantiation of duration requires a diagnostic.
-That's followed by an operator/ that takes two durations.
-So dur1 / dur2 is legal under the second version,
-but requires a diagnostic under the first.
-
      
-
-
      [
-Howard adds:
-]
      
-
-
-
      
-Please see the thread starting with c++std-lib-22980 for more information.
-
      
-
-
      [
-Batavia (2009-05):
-]
      
-
-
      
-Move to Open, pending proposed wording (and preferably an implementation).
-
      
-
-
      [
-2009-07-27 Howard adds:
-]
      
-
-
-
      
-
      
-I've addressed this issue under the proposed wording for 1177 which
-cleans up several places under 20.9.3 [time.duration] which used the
-phrase "diagnostic required".
-
      
-
      
-For clarity's sake, here is an example implementation of the constrained operator/:
-
      
-
-
      template <class _Duration, class _Rep, bool = __is_duration<_Rep>::value>
-struct __duration_divide_result
-{
-};
-
-template <class _Duration, class _Rep2,
-    bool = is_convertible<_Rep2,
-                          typename common_type<typename _Duration::rep, _Rep2>::type>::value>
-struct __duration_divide_imp
-{
-};
-
-template <class _Rep1, class _Period, class _Rep2>
-struct __duration_divide_imp<duration<_Rep1, _Period>, _Rep2, true>
-{
-    typedef duration<typename common_type<_Rep1, _Rep2>::type, _Period> type;
-};
-
-template <class _Rep1, class _Period, class _Rep2>
-struct __duration_divide_result<duration<_Rep1, _Period>, _Rep2, false>
-    : __duration_divide_imp<duration<_Rep1, _Period>, _Rep2>
-{
-};
-
-template <class _Rep1, class _Period, class _Rep2>
-inline
-typename __duration_divide_result<duration<_Rep1, _Period>, _Rep2>::type
-operator/(const duration<_Rep1, _Period>& __d, const _Rep2& __s)
-{
-    typedef typename common_type<_Rep1, _Rep2>::type _Cr;
-    duration<_Cr, _Period> __r = __d;
-    __r /= static_cast<_Cr>(__s);
-    return __r;
-}
+
      (a < b) ? distance(a,b)
+: -distance(b,a)
 
      
+
      2. 
 
+
    2. 
 
      
-__duration_divide_result is basically a custom-built enable_if
-that will contain type only if Rep2 is not a duration
-and if Rep2 is implicitly convertible to
-common_type<typename Duration::rep, Rep2>::type. __is_duration
-is simply a private trait that answers false, but is specialized for
-duration to answer true.
+Change 24.4.4 [iterator.operations]/4+5 as indicated:
+
      
+
+
      template<class InputIterator>
+  typename iterator_traits<InputIterator>::difference_type
+    distance(InputIterator first, InputIterator last);
+
      
+
      
+
      
+4 Effects: If InputIterator meets the requirements
+of random access iterator then returns (last - first),
+otherwise Rreturns the number of increments
+or decrements needed to get from first to
+last.
 
      
 
 
      
-The constrained operator% works identically.
+5 Requires: If InputIterator meets the requirements
+of random access iterator then last shall be reachable from
+first or first shall be reachable from last,
+otherwise last shall be reachable from first.
 
      
 
      
+
      
+
      3. 
+
    
+
+
 
 
-
    Proposed resolution:
    
-
    
-
    
 
 
 
@@ -19088,11 +12748,11 @@ The constrained operator% works identically.
 
 
    
 
    950. unique_ptr converting ctor shouldn't accept array form
    
-
    Section: 20.8.9.2.1 [unique.ptr.single.ctor] Status: Review
- Submitter: Howard Hinnant Opened: 2009-01-07  Last modified: 2009-08-01
    
+
    Section: 20.8.14.2.1 [unique.ptr.single.ctor] Status: Ready
+ Submitter: Howard Hinnant Opened: 2009-01-07  Last modified: 2009-10-21
    
 
    View other active issues in [unique.ptr.single.ctor].
    
 
    View all other issues in [unique.ptr.single.ctor].
    
-
    View all issues with Review status.
    
+
    View all issues with Ready status.
    
 
    Discussion:
    
 
    
 unique_ptr's of array type should not convert to
@@ -19157,11 +12817,20 @@ formula.
 ]
    
 
 
+
    [
+2009-10 Santa Cruz:
+]
    
+
+
+
    
+Move to Ready.
+
    
+
 
 
 
    Proposed resolution:
    
 
    
-Change 20.8.9.2.1 [unique.ptr.single.ctor]:
+Change 20.8.14.2.1 [unique.ptr.single.ctor]:
 
    
 
 
    
@@ -19193,7 +12862,7 @@ imply that T and U are complete types. — end note
 
    
 
 
    
-Change 20.8.9.2.3 [unique.ptr.single.asgn]:
+Change 20.8.14.2.3 [unique.ptr.single.asgn]:
 
    
 
 
    
@@ -19229,7 +12898,7 @@ are complete types. — end note]
 
    
 
    951. Various threading bugs #1
    
 
    Section: 20.9.2.1 [time.traits.is_fp] Status: Open
- Submitter: Pete Becker Opened: 2009-01-07  Last modified: 2009-08-01
    
+ Submitter: Pete Becker Opened: 2009-01-07  Last modified: 2009-10-23
    
 
    View all issues with Open status.
    
 
    Discussion:
    
 
@@ -19334,7 +13003,7 @@ but none has been pointed out).
 
    
 
 
    
-I am amenable to improved wording of this paragraph (and any others), but to not have any
+I am amenable to improved wording of this paragraph (and any others), but do not have any
 suggestions for improved wording at this time.  I am strongly opposed to
 changes which would significantly alter the semantics of the
 specification under 20.9 [time] without firmly grounded and
@@ -19347,6 +13016,16 @@ I recommend NAD unless someone wants to produce some clarifying wording.
 
    
 
    
 
+
    [
+2009-10 Santa Cruz:
+]
    
+
+
+
    
+Stefanus to provide wording to turn this into a note.
+
    
+
+
 
 
    Proposed resolution:
    
 
    
@@ -19359,7 +13038,7 @@ I recommend NAD unless someone wants to produce some clarifying wording.
 
    
 
    953. Various threading bugs #3
    
 
    Section: 20.9.1 [time.clock.req] Status: Open
- Submitter: Pete Becker Opened: 2009-01-07  Last modified: 2009-08-01
    
+ Submitter: Pete Becker Opened: 2009-01-07  Last modified: 2009-10-23
    
 
    View other active issues in [time.clock.req].
    
 
    View all other issues in [time.clock.req].
    
 
    View all issues with Open status.
    
@@ -19415,6 +13094,16 @@ We look forward to proposed wording.  Move to Open.
 See commented dated 2009-08-01 in 951.
 
    
 
+
    [
+2009-10 Santa Cruz:
+]
    
+
+
+
    
+Stefanus to provide wording to turn this into a note.
+
    
+
+
 
 
    Proposed resolution:
    
 
    
@@ -19426,11 +13115,11 @@ See commented dated 2009-08-01 in 954. Various threading bugs #4
-
    Section: 20.9.1 [time.clock.req] Status: Review
- Submitter: Pete Becker Opened: 2009-01-07  Last modified: 2009-08-01
    
+
    Section: 20.9.1 [time.clock.req] Status: Ready
+ Submitter: Pete Becker Opened: 2009-01-07  Last modified: 2009-10-21
    
 
    View other active issues in [time.clock.req].
    
 
    View all other issues in [time.clock.req].
    
-
    View all issues with Review status.
    
+
    View all issues with Ready status.
    
 
    Discussion:
    
 
    
 Table 55 -- Clock Requirements (in 20.9.1 [time.clock.req])
@@ -19570,6 +13259,15 @@ which is part of ISO/IEC 18026 "Information technology -- Spatial Reference Mode
 ]
    
 
 
+
    [
+2009-10 Santa Cruz:
+]
    
+
+
+
    
+Move to Ready.
+
    
+
 
 
 
    Proposed resolution:
    
@@ -19634,352 +13332,10 @@ The tick period of the clock in seconds.
 
 
 
-
    
-
    955. Various threading bugs #5
    
-
    Section: 20.9.1 [time.clock.req] Status: Open
- Submitter: Pete Becker Opened: 2009-01-07  Last modified: 2009-06-07
    
-
    View other active issues in [time.clock.req].
    
-
    View all other issues in [time.clock.req].
    
-
    View all issues with Open status.
    
-
    Discussion:
    
-
    
-20.9.1 [time.clock.req] requires that a clock type have a member
-typedef named time_point that names an instantiation of the
-template time_point, and a member named duration that
-names an instantiation of the template duration. This mixing of
-levels is confusing. The typedef names should be different from the
-template names.
-
    
-
-
    [
-Post Summit, Anthony provided proposed wording.
-]
    
-
-
-
    [
-2009-05-04 Howard adds:
-]
    
-
-
-
    
-
    
-The reason that the typedef names were given the same name as the class templates
-was so that clients would not have to stop and think about whether they were
-using the clock's native time_point / duration or the class
-template directly.  In this case, one person's confusion is another person's
-encapsulation.  The detail that sometimes one is referring to the clock's
-native types, and sometimes one is referring to an independent type is
-purposefully "hidden" because it is supposed to be an unimportant
-detail.  It can be confusing to have to remember when to type duration
-and when to type duration_type, and there is no need to require the
-client to remember something like that.
-
    
-
-
    
-For example, here is code that I once wrote in testing out the usability of
-this facility:
-
    
-
-
    template <class Clock, class Duration>
-void do_until(const std::chrono::time_point<Clock, Duration>& t)
-{
-    typename Clock::time_point now = Clock::now();
-    if (t > now)
-    {
-        typedef typename std::common_type
-        <
-            Duration,
-            typename std::chrono::system_clock::duration
-        >::type CD;
-        typedef std::chrono::duration<double, std::nano> ID;
-
-        CD d = t - now;
-        ID us = duration_cast<ID>(d);
-        if (us < d)
-            ++us;
-        ...
-    }
-}
-
    
-
-
    
-I see no rationale to require the client to append _type to some
-of those declarations.  It seems overly burdensome on the author of do_until:
-
    
-
-
    template <class Clock, class Duration>
-void do_until(const std::chrono::time_point<Clock, Duration>& t)
-{
-    typename Clock::time_point_type now = Clock::now();
-    if (t > now)
-    {
-        typedef typename std::common_type
-        <
-            Duration,
-            typename std::chrono::system_clock::duration_type
-        >::type CD;
-        typedef std::chrono::duration<double, std::nano> ID;
-
-        CD d = t - now;
-        ID us = duration_cast<ID>(d);
-        if (us < d)
-            ++us;
-        ...
-    }
-}
-
    
-
-
    
-Additionally I'm fairly certain that this suggestion hasn't been implemented.
-If it had, it would have been discovered that it is incomplete.  time_point
-also has a nested type (purposefully) named duration.
-
    
-
    
-That is, the current proposed wording would put the WP into an inconsistent state.
-
    
-
    
-In contrast,
-the current WP has been implemented and I've received very favorable feedback
-from people using this interface in real-world code.
-
    
-
-
    
-
-
    [
-Batavia (2009-05):
-]
    
-
-
    
-
    
-Bill agrees that distinct names should be used for distinct kinds of entities.
-
    
-
    
-Walter would prefer not to suffix type names,
-especially for such well-understood terms as "duration".
-
    
-
    
-Howard reminds us that the proposed resolution is incomplete, per his comment
-in the issue.
-
    
-
    
-Move to Open.
-
    
-
    
-
-
    [
-2009-06-07 Howard adds:
-]
    
-
-
-
    
-
    
-Not meaning to be argumentative, but we have a decade of positive experience
-with the precedent of using the same name for the nested type as an external
-class representing an identical concept.
-
    
-
-
    template<class Category, class T, class Distance = ptrdiff_t,
-         class Pointer = T*, class Reference = T&>
-struct iterator
-{
-    ...
-};
-
-template <BidirectionalIterator Iter>
-class reverse_iterator
-{
-    ...
-};
-
-template <ValueType T, Allocator Alloc = allocator<T> >
-    requires NothrowDestructible<T>
-class list
-{
-public:
-    typedef implementation-defined     iterator;
-    ...
-    typedef reverse_iterator<iterator> reverse_iterator;
-    ...
-};
-
    
-
-
    
-I am aware of zero complaints regarding the use of iterator
-and reverse_iterator as nested types of the containers despite these
-names also having related meaning at namespace std scope.
-
    
-
-
    
-Would we really be doing programmers a favor by renaming these nested types?
-
    
-
-
    template <ValueType T, Allocator Alloc = allocator<T> >
-    requires NothrowDestructible<T>
-class list
-{
-public:
-    typedef implementation-defined     iterator_type;
-    ...
-    typedef reverse_iterator<iterator> reverse_iterator_type;
-    ...
-};
-
    
-
-
    
-I submit that such design contributes to needless verbosity which ends up
-reducing readability.
-
    
-
    
-
-
-
-
    Proposed resolution:
    
-
    
-Change 20.9 [time]:
-
    
-
-
    ...
-template <class Clock, class Duration = typename Clock::duration_type> class time_point;
-...
-
    
-
-
    
-Change 20.9.1 [time.clock.req]:
-
    
-
-
    
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
    Table 45 -- Clock requirements
    ExpressionReturn typeOperational semantics
    .........
    C1::duration_typechrono::duration<C1::rep, C1::period>The native duration type of the clock.
    C1::time_point_typechrono::time_point<C1> or chrono::time_point<C2, C1::duration_type<The native time_point type of the clock.   Different clocks may  share a time_point_type
-definition if it is valid to 
-compare their time_point_types by 
-comparing their respective 
-duration_types. C1 and C2 shall 
-refer to the same epoch.
    .........
    C1::now()C1::time_point_typeReturns a time_point_type object 
-representing the current point 
-in time.
-
    
-
    
-
-
    
-Change 20.9.5.1 [time.clock.system]:
-
    
-
-
    
-
    
--1- Objects of class system_clock represent wall clock time from the system-wide realtime clock.
-
    
-
-
    class system_clock { 
-public: 
-  typedef see below rep; 
-  typedef ratio<unspecified, unspecified> period; 
-  typedef chrono::duration<rep, period> duration_type; 
-  typedef chrono::time_point<system_clock> time_point_type; 
-  static const bool is_monotonic = unspecified ; 
-
-  static time_point_type now(); 
-
-  // Map to C API 
-  static time_t to_time_t (const time_point_type& t); 
-  static time_point_type from_time_t(time_t t); 
-};
-
    
-
-
    
--2- system_clock::duration_type::min() < system_clock::duration_type::zero() shall be true.
-
    
-
-
    time_t to_time_t(const time_point_type& t);
-
    
-
-
    
--3- Returns: A time_t object that represents the same
-point in time as t when both values are truncated to the
-coarser of the precisions of time_t and time_point_type.
-
    
-
-
    time_point_type from_time_t(time_t t);
-
    
-
-
    
--4- Returns: A time_point_type object that represents the same point
-in time as t when both values are truncated to the coarser of the
-precisions of time_t and time_point_type.
-
    
-
    
-
-
    
-Change 20.9.5.2 [time.clock.monotonic]:
-
    
-
-
    class monotonic_clock { 
-public: 
-  typedef unspecified                                rep; 
-  typedef ratio<unspecified , unspecified>           period; 
-  typedef chrono::duration<rep, period>              duration_type; 
-  typedef chrono::time_point<unspecified , duration_type> time_point_type; 
-  static const bool is_monotonic =                   true; 
-
-  static time_point_type now();
-};
-
    
-
-
    
-Change 20.9.5.3 [time.clock.hires]:
-
    
-
-
    class high_resolution_clock { 
-public: 
-  typedef unspecified                                rep; 
-  typedef ratio<unspecified , unspecified>           period; 
-  typedef chrono::duration<rep, period>              duration_type; 
-  typedef chrono::time_point<unspecified , duration_type> time_point_type; 
-  static const bool is_monotonic =                   true; 
-
-  static time_point_type now();
-};
-
    
-
-
-
-
-
-
 
    
 
    956. Various threading bugs #6
    
 
    Section: 20.9.1 [time.clock.req] Status: Open
- Submitter: Pete Becker Opened: 2009-01-07  Last modified: 2009-05-23
    
+ Submitter: Pete Becker Opened: 2009-01-07  Last modified: 2009-10-24
    
 
    View other active issues in [time.clock.req].
    
 
    View all other issues in [time.clock.req].
    
 
    View all issues with Open status.
    
@@ -20010,21 +13366,39 @@ Batavia (2009-05):
 Move to Open pending proposed wording from Pete.
    +

    [ +2009-10-23 Pete provides wording: +]

    + +

    Proposed resolution:

    +Remove every occurrence of "native" in 20.9.1 [time.clock.req].

    +

    +Add the following sentence at the end of 20.9.1 [time.clock.req]/1: +

    + +
    +A clock is a bundle consisting of a native duration, a native +time_point, and a function now() to get the current time_point. A clock +shall meet the requirements in Table 55. +The duration and time_point types have the natural size and resolution +suggested by the architecture of the execution environment. +
    +

    957. Various threading bugs #7

    -

    Section: 20.9.5.1 [time.clock.system] Status: Review - Submitter: Pete Becker Opened: 2009-01-07 Last modified: 2009-05-23

    +

    Section: 20.9.5.1 [time.clock.system] Status: Ready + Submitter: Pete Becker Opened: 2009-01-07 Last modified: 2009-10-21

    View all other issues in [time.clock.system].

    -

    View all issues with Review status.

    +

    View all issues with Ready status.

    Discussion:

    20.9.5.1 [time.clock.system]: to_time_t is overspecified. It @@ -20058,6 +13432,16 @@ Move to Review pending input from Howard. and other stakeholders. I am in favor of the wording provided by Anthony. +

    [ +2009-10 Santa Cruz: +]

    + + +
    +Move to Ready. +
    + +

    Proposed resolution:

    @@ -20092,58 +13476,10 @@ rounded or truncated to the required precision. -

    -

    958. Various threading bugs #8

    -

    Section: 30.5.1 [thread.condition.condvar] Status: Open - Submitter: Pete Becker Opened: 2009-01-07 Last modified: 2009-08-01

    -

    View other active issues in [thread.condition.condvar].

    -

    View all other issues in [thread.condition.condvar].

    -

    View all issues with Open status.

    -

    Discussion:

    -

    -30.5.1 [thread.condition.condvar]: the specification for wait_for -with no predicate has an effects clause that says it calls wait_until, -and a returns clause that sets out in words how to determine the return -value. Is this description of the return value subtly different from the -description of the value returned by wait_until? Or should the effects -clause and the returns clause be merged? -

    - -

    [ -Summit: -]

    - - -
    -Move to open. Associate with LWG 859 and any other monotonic-clock -related issues. -
    - -

    [ -2009-08-01 Howard adds: -]

    - - -
    -I believe that 859 (currently Ready) addresses this issue, and -that this issue should be marked NAD, solved by 859 (assuming -it moves to WP). -
    - - - -

    Proposed resolution:

    -

    -

    - - - - -

    959. Various threading bugs #9

    Section: 30.5.1 [thread.condition.condvar] Status: Open - Submitter: Pete Becker Opened: 2009-01-07 Last modified: 2009-08-01

    + Submitter: Pete Becker Opened: 2009-01-07 Last modified: 2009-10-26

    View other active issues in [thread.condition.condvar].

    View all other issues in [thread.condition.condvar].

    View all issues with Open status.

    @@ -20161,7 +13497,7 @@ Summit:
    -Move to open. Associate with LWG 859 and any other monotonic-clock +Move to open. Associate with LWG 859 and any other monotonic-clock related issues.
    @@ -20171,11 +13507,20 @@ related issues.
    -I believe that 859 (currently Ready) addresses this issue, and -that this issue should be marked NAD, solved by 859 (assuming +I believe that 859 (currently Ready) addresses this issue, and +that this issue should be marked NAD, solved by 859 (assuming it moves to WP).
    +

    [ +2009-10 Santa Cruz: +]

    + + +
    +Leave open, but expect to be fixed by N2969 revision that Detlef is writing. +
    +

    Proposed resolution:

    @@ -20188,11 +13533,11 @@ it moves to WP).

    960. Various threading bugs #10

    -

    Section: 30.4.1 [thread.mutex.requirements] Status: Open - Submitter: Pete Becker Opened: 2009-01-07 Last modified: 2009-03-27

    +

    Section: 30.4.1 [thread.mutex.requirements] Status: Ready + Submitter: Pete Becker Opened: 2009-01-07 Last modified: 2009-10-26

    View other active issues in [thread.mutex.requirements].

    View all other issues in [thread.mutex.requirements].

    -

    View all issues with Open status.

    +

    View all issues with Ready status.

    Discussion:

    30.4.1 [thread.mutex.requirements]: paragraph 4 is entitled @@ -20216,6 +13561,17 @@ Beman provided proposed wording. ]

    +

    [ +2009-10 Santa Cruz: +]

    + + +
    +Move to Ready. Fix the proposed wording with "functions of type Mutex" +-> "functions of Mutex type" +
    + +

    Proposed resolution:

    @@ -20227,7 +13583,7 @@ paragraph 4 as indicated:

    -4- Error conditions: The error conditions for error codes, if any, reported by member -functions of type Mutex shall be: +functions of Mutex type shall be:

    • @@ -20257,47 +13613,13 @@ part of mutex construction is incorrect. -
      -

      961. Various threading bugs #11

      -

      Section: 30.4.1 [thread.mutex.requirements] Status: Open - Submitter: Pete Becker Opened: 2009-01-07 Last modified: 2009-03-22

      -

      View other active issues in [thread.mutex.requirements].

      -

      View all other issues in [thread.mutex.requirements].

      -

      View all issues with Open status.

      -

      Discussion:

      -

      -30.4.1 [thread.mutex.requirements] describes required member -functions of mutex types, and requires that they throw exceptions under -certain circumstances. This is overspecified. User-defined types can -abort on such errors without affecting the operation of templates -supplied by standard-library. -

      - -

      [ -Summit: -]

      - -
      -Move to open. Related to conceptualization and should probably be -tackled as part of that. -
      - - -

      Proposed resolution:

      -

      -

      - - - - -

      962. Various threading bugs #12

      -

      Section: 30.4.3.2.2 [thread.lock.unique.locking] Status: Review - Submitter: Pete Becker Opened: 2009-01-07 Last modified: 2009-07-21

      +

      Section: 30.4.3.2.2 [thread.lock.unique.locking] Status: Ready + Submitter: Pete Becker Opened: 2009-01-07 Last modified: 2009-10-22

      View other active issues in [thread.lock.unique.locking].

      View all other issues in [thread.lock.unique.locking].

      -

      View all issues with Review status.

      +

      View all issues with Ready status.

      Discussion:

      30.4.3.2.2 [thread.lock.unique.locking]: unique_lock::lock is @@ -20322,10 +13644,24 @@ Beman has volunteered to provide proposed wording.

      [ 2009-07-21 Beman added wording to address 30.2.2 [thread.req.exception] -in response to the Frankfurt notes in 859. +in response to the Frankfurt notes in 859. ]

      +

      [ +2009-09-25 Beman: minor update to wording. +]

      + + +

      [ +2009-10 Santa Cruz: +]

      + + +
      +Move to Ready. +
      +

      Proposed resolution:

      @@ -20337,18 +13673,19 @@ type system_error (19.5.5). Such exceptions shall be thrown if Error conditions are detected or a call to an operating system or other underlying API results in an error that prevents the library function from satisfying its postconditions or from returning a meaningful -value meeting its specifications. Nevertheless, failure to -allocate storage shall be reported as described in [res.on.exception.handling].

      +value meeting its specifications. Failure to +allocate storage shall be reported as described in +17.6.4.11 [res.on.exception.handling].

      -

      Change thread assignment 30.3.1.4 [thread.thread.assign], join(), +

      Change thread assignment 30.3.1.5 [thread.thread.member], join(), paragraph 8 as indicated:

      Throws: std::system_error when the postconditions cannot be achieved an exception is required (30.2.2 [thread.req.exception]).

      -

      Change thread assignment 30.3.1.4 [thread.thread.assign], detach(), paragraph +

      Change thread assignment 30.3.1.5 [thread.thread.member], detach(), paragraph 13 as indicated:

      @@ -20429,7 +13766,7 @@ paragraph 16, as indicated:

      postcondition cannot be achieved an exception is required (30.2.2 [thread.req.exception]).

      -

      Assuming issue 859, Monotonic Clock is Conditionally Supported?, has been +

      Assuming issue 859, Monotonic Clock is Conditionally Supported?, has been applied to the working paper, change Change 30.5.1 [thread.condition.condvar] as indicated:

      @@ -20442,7 +13779,7 @@ bool wait_for(unique_lock<mutex>& lock, postcondition cannot be achieved an exception is required ([thread.req.exception]).

      -

      Assuming issue 859, Monotonic Clock is Conditionally Supported?, has been +

      Assuming issue 859, Monotonic Clock is Conditionally Supported?, has been applied to the working paper, change Change 30.5.1 [thread.condition.condvar] as indicated:

      @@ -20456,7 +13793,7 @@ indicated:

      postcondition cannot be achieved an exception is required (30.2.2 [thread.req.exception]).

      -

      Assuming issue 859, Monotonic Clock is Conditionally Supported?, has been +

      Assuming issue 859, Monotonic Clock is Conditionally Supported?, has been applied to the working paper, change 30.5.2 [thread.condition.condvarany] as indicated:

      @@ -20468,7 +13805,7 @@ indicated:

      postcondition cannot be achieved an exception is required (30.2.2 [thread.req.exception]).

      -

      Assuming issue 859, Monotonic Clock is Conditionally Supported?, has been +

      Assuming issue 859, Monotonic Clock is Conditionally Supported?, has been applied to the working paper, change 30.5.2 [thread.condition.condvarany] as indicated:

      @@ -20487,11 +13824,11 @@ postcondition cannot be achieved an exception is required (30.2.2 [th

      963. Various threading bugs #13

      -

      Section: 30.3.1.5 [thread.thread.member] Status: Open - Submitter: Pete Becker Opened: 2009-01-07 Last modified: 2009-03-22

      +

      Section: 30.3.1.5 [thread.thread.member] Status: Ready + Submitter: Pete Becker Opened: 2009-01-07 Last modified: 2009-10-26

      View other active issues in [thread.thread.member].

      View all other issues in [thread.thread.member].

      -

      View all issues with Open status.

      +

      View all issues with Ready status.

      Discussion:

      30.3.1.5 [thread.thread.member]: thread::detach is required to @@ -20610,10 +13947,37 @@ In 30.3.1.5 [thread.thread.member] change:

      +

      [ +2009-10 Santa Cruz: +]

      + + +
      +Mark as Ready with proposed resolution from Summit. +
      +

      Proposed resolution:

      +

      +In 30.3.1.5 [thread.thread.member] change: +

      + +
      void detach();
+
      +
      +

      ...

      +

      -14- Error conditions:

      +
        +
      • no_such_process -- if the thread is not a valid thread.
        • +
      • invalid_argument -- if the thread is not a detachable joinable thread.
        • +
      +
      + +
      + + @@ -20621,7 +13985,9 @@ In 30.3.1.5 [thread.thread.member] change:

      964. Various threading bugs #14

      Section: 30.5.2 [thread.condition.condvarany] Status: Open - Submitter: Pete Becker Opened: 2009-01-07 Last modified: 2009-03-22

      + Submitter: Pete Becker Opened: 2009-01-07 Last modified: 2009-10-26

      +

      View other active issues in [thread.condition.condvarany].

      +

      View all other issues in [thread.condition.condvarany].

      View all issues with Open status.

      Discussion:

      @@ -20656,6 +14022,16 @@ received any complaints about specific error conditions from vendors on non-POSIX platforms, but such complaints would not surprise me if they surfaced. +

      [ +2009-10 Santa Cruz: +]

      + + +
      +Leave open. Benjamin to provide wording. +
      + +

      Proposed resolution:

      @@ -20666,17 +14042,19 @@ non-POSIX platforms, but such complaints would not surprise me if they surfaced.

      966. Various threading bugs #16

      Section: 30.5.1 [thread.condition.condvar] Status: Open - Submitter: Pete Becker Opened: 2009-01-07 Last modified: 2009-08-01

      + Submitter: Pete Becker Opened: 2009-01-07 Last modified: 2009-10-26

      View other active issues in [thread.condition.condvar].

      View all other issues in [thread.condition.condvar].

      View all issues with Open status.

      Discussion:

      -30.5.1 [thread.condition.condvar]: condition_variable::wait and -condition_variable::wait_until both have a postcondition that lock is -locked by the calling thread, and a throws clause that requires throwing -an exception if this postcondition cannot be achieved. How can the -implementation detect that this lock can never be obtained? +30.5.1 [thread.condition.condvar]: +condition_variable::wait and +condition_variable::wait_until both have a postcondition that +lock is locked by the calling thread, and a throws clause that +requires throwing an exception if this postcondition cannot be achieved. +How can the implementation detect that this lock can never be +obtained?

      [ @@ -20716,9 +14094,25 @@ OS's are POSIX.

      +

      [ +2009-10 Santa Cruz: +]

      -

      Proposed resolution:

      +
      +Leave open, Detlef to provide improved wording. +
      + +

      [ +2009-10-23 Detlef Provided wording. +]

      + + +
      +

      +Detlef's wording put in Proposed resolution. Original wording here: +

      +

      Change 30.5.1 [thread.condition.condvar] p12, p19 and 30.5.2 [thread.condition.condvarany] p10, p16: @@ -20732,6 +14126,47 @@ if a precondition is not met. when the effects or postcondition cannot be achieved.

      +
      + + +

      [ +2009-10 Santa Cruz: +]

      + + +
      +Leave open, Detlef to provide improved wording. +
      + + + +

      Proposed resolution:

      +

      +Replace 30.5.1 [thread.condition.condvar] p12, p19 and +30.5.2 [thread.condition.condvarany] p10, p16: +

      + +
      +

      +Throws: std::system_error when the effects or +postcondition cannot be achieved. +

      +

      +Error conditions: +

      +
        +
      • +equivalent error condition from lock.lock() or lock.unlock(). +
        • +
      + +

      +Throws: It's implementation-defined whether a std::system_error +with implementation-defined error condition is thrown if the +precondition is not met. +

      +
      + @@ -20739,11 +14174,11 @@ cannot be achieved.

      967. Various threading bugs #17

      -

      Section: 30.3.1.2 [thread.thread.constr] Status: Review - Submitter: Pete Becker Opened: 2009-01-07 Last modified: 2009-06-27

      +

      Section: 30.3.1.2 [thread.thread.constr] Status: Ready + Submitter: Pete Becker Opened: 2009-01-07 Last modified: 2009-10-22

      View other active issues in [thread.thread.constr].

      View all other issues in [thread.thread.constr].

      -

      View all issues with Review status.

      +

      View all issues with Ready status.

      Discussion:

      the error handling for the constructor for condition_variable @@ -20757,19 +14192,29 @@ Beman has volunteered to provide proposed wording. ]

      +

      [ +2009-09-25 Beman provided proposed wording. +]

      + + +
      +The proposed resolution assumes 962 has been accepted and +its proposed resolution applied to the working paper. +
      + +

      [ +2009-10 Santa Cruz: +]

      + + +
      +Move to Ready. +
      + +

      Proposed resolution:

      -

      Change Exceptions 30.2.2 [thread.req.exception] as indicated:

      -
      -

      Some functions described in this Clause are -specified to throw exceptions of type system_error (19.5.5). Such exceptions -shall be thrown if any of the Error conditions are detected or a call to an operating system or other underlying API -results in an error that prevents the library function from meeting its specifications. -[Note: See 17.6.4.10 [res.on.exception.handling] for exceptions thrown to report -storage allocation failures. --end -note]

      -

      Change Mutex requirements 30.4.1 [thread.mutex.requirements], paragraph 4, as indicated:

      @@ -20807,11 +14252,11 @@ default constructor, as indicated:

      Error conditions:

        -
      • not_enough_memory &msash; if a memory limitation prevents +
      • not_enough_memory — if a memory limitation prevents initialization.
        • -
      • resource_unavailable_try_again &msash; if some non-memory +
      • resource_unavailable_try_again — if some non-memory resource limitation prevents initialization.
        • -
      • device_or_resource_busy &msash; if attempting to initialize a +
      • device_or_resource_busy — if attempting to initialize a previously-initialized but as of yet undestroyed condition_variable.
      @@ -20824,11 +14269,11 @@ default constructor, as indicated:

      968. Various threading bugs #18

      -

      Section: 30.4.1 [thread.mutex.requirements] Status: Review - Submitter: Pete Becker Opened: 2009-01-07 Last modified: 2009-06-27

      +

      Section: 30.4.1 [thread.mutex.requirements] Status: Ready + Submitter: Pete Becker Opened: 2009-01-07 Last modified: 2009-10-22

      View other active issues in [thread.mutex.requirements].

      View all other issues in [thread.mutex.requirements].

      -

      View all issues with Review status.

      +

      View all issues with Ready status.

      Discussion:

      30.4.1 [thread.mutex.requirements]: several functions are @@ -20850,6 +14295,16 @@ Beman has volunteered to provide proposed wording. ]

      +

      [ +2009-10 Santa Cruz: +]

      + + +
      +Moved to Ready with minor word-smithing in the example. +
      + +

      Proposed resolution:

      @@ -20860,7 +14315,7 @@ Beman has volunteered to provide proposed wording. specified to throw exceptions of type system_error (19.5.5). Such exceptions shall be thrown if any of the Error conditions are detected or a call to an operating system or other underlying API results in an error that prevents the library function from meeting its specifications. -[Note: See 17.6.4.10 [res.on.exception.handling] for exceptions thrown to report +[Note: See 17.6.4.11 [res.on.exception.handling] for exceptions thrown to report storage allocation failures. —end note]

      @@ -20868,10 +14323,10 @@ note]

      -

      A function in this clause that is specified to throw exceptions of type +

      Consider a function in this clause that is specified to throw exceptions of type system_error and specifies Error conditions that include operation_not_permitted for a thread that does not have the privilege to -perform the operation. During the execution of this function, an errno +perform the operation. Assume that, during the execution of this function, an errno of EPERM is reported by a POSIX API call used by the implementation. Since POSIX specifies an errno of EPERM when "the caller does not have the privilege to perform the operation", @@ -20915,114 +14370,11 @@ paragraph 12, as indicated:

      -
      -

      971. Spurious diagnostic conversion function

      -

      Section: 19.5.2.6 [syserr.errcode.nonmembers] Status: Tentatively NAD - Submitter: Beman Dawes Opened: 2009-01-19 Last modified: 2009-07-22

      -

      View all issues with Tentatively NAD status.

      -

      Discussion:

      -

      -Anthony Williams raised the question in c++std-lib-22987 "why is there -std::make_error_code(std::errc)? What purpose does this serve?" -

      -

      -The function make_error_code(errc e) is not required, since -make_error_condition(errc e) is the function that is needed for errc -conversions. make_error_code(errc e) appears to be a holdover from my -initial confusion over the distinction between POSIX and operating -systems that conform to the POSIX spec. -

      - -

      [ -Post Summit: -]

      - - -
      -Recommend Review. -
      - -

      [ -Batavia (2009-05): -]

      - -
      -The designer of the facility (Christopher Kohlhoff) -strongly disagrees that there is an issue here, -and especially disagrees with the proposed resolution. -Bill would prefer to be conservative and not apply this proposed resolution. -Move to Open, and recommend strong consideration for NAD status. -
      - -

      [ -2009-05-21 Beman adds: -]

      - - -
      -My mistake. Christopher and Bill are correct and the issue should be -NAD. The function is needed by users. -
      - -

      [ -2009-07-21 Christopher Kohlhoff adds rationale for make_error_code: -]

      - - -
      -

      -Users (and indeed library implementers) may need to use the -errc codes in portable code. For example: -

      - -
      void do_foo(error_code& ec)
-{
-#if defined(_WIN32)
-  // Windows implementation ...
-#elif defined(linux)
-  // Linux implementation ...
-#else
-  // do_foo not supported on this platform
-  ec = make_error_code(errc::not_supported);
-#endif
-}
-
      -
      - - -

      Proposed resolution:

      -

      -Change System error support 19.5 [syserr], Header <system_error> -synopsis, as indicated: -

      - -
      error_code make_error_code(errc e);
-error_condition make_error_condition(errc e);
-
      - -

      -Delete from Class error_code non-member functions -19.5.2.6 [syserr.errcode.nonmembers]: -

      - -
      error_code make_error_code(errc e);
-
      -
      -Returns: error_code(static_cast<int>(e), -generic_category). -
      -
      - - - - - -

      974. duration<double> should not implicitly convert to duration<int>

      -

      Section: 20.9.3.1 [time.duration.cons] Status: Open - Submitter: Howard Hinnant Opened: 2009-01-21 Last modified: 2009-08-01

      -

      View all issues with Open status.

      +

      Section: 20.9.3.1 [time.duration.cons] Status: Ready + Submitter: Howard Hinnant Opened: 2009-01-21 Last modified: 2009-10-26

      +

      View all issues with Ready status.

      Discussion:

      The following code should not compile because it involves implicit truncation @@ -21072,6 +14424,15 @@ formula. Addressed by 1177.

      +

      [ +2009-10 Santa Cruz: +]

      + + +
      +Not completely addressed by 1177. Move to Ready. +
      +

      Proposed resolution:

      @@ -21101,389 +14462,15 @@ construction could easily lead to confusion about the value of the -
      -

      976. Class template std::stack should be movable

      -

      Section: 23.3.5.3.1 [stack.defn] Status: Open - Submitter: Daniel Krügler Opened: 2009-02-01 Last modified: 2009-07-14

      -

      View all issues with Open status.

      -

      Discussion:

      -

      -The synopsis given in 23.3.5.3.1 [stack.defn] does not show up -

      - -
      requires MoveConstructible<Cont> stack(stack&&);
-requires MoveAssignable<Cont> stack& operator=(stack&&);
-
      - -

      -although the other container adaptors do provide corresponding -members. -

      - -

      [ -Batavia (2009-05): -]

      - -
      -

      -We agree with the proposed resolution. -

      -

      -Move to Tentatively Ready. -

      -
      - -

      [ -2009-07 Frankfurt -]

      - - -
      -Moved from Tentatively Ready to Open only because the wording needs to be -tweaked for concepts removal. -
      - - - -

      Proposed resolution:

      -

      -In the class stack synopsis of 23.3.5.3.1 [stack.defn] insert: -

      - -
      template <ObjectType T, StackLikeContainer Cont = deque<T> > 
-  requires SameType<Cont::value_type, T> 
-        && NothrowDestructible<Cont> 
-class stack { 
-public: 
-   ...
-   requires CopyConstructible<Cont> explicit stack(const Cont&); 
-   requires MoveConstructible<Cont> explicit stack(Cont&& = Cont()); 
-   requires MoveConstructible<Cont> stack(stack&&);
-   requires MoveAssignable<Cont> stack& operator=(stack&&);
-   template <class Alloc> 
-     requires Constructible<Cont, const Alloc&> 
-     explicit stack(const Alloc&);
-   ...
-};
-
      - -

      -[Remark: This change should be done in sync with the resolution of -paper -N2819] -

      - - - - - - -
      -

      977. insert iterators inefficient for expensive to move types

      -

      Section: 24.7 [insert.iterators] Status: Open - Submitter: Howard Hinnant Opened: 2009-02-02 Last modified: 2009-05-23

      -

      View other active issues in [insert.iterators].

      -

      View all other issues in [insert.iterators].

      -

      View all issues with Open status.

      -

      Discussion:

      -

      -The new concepts for the insert iterators mandate an extra copy when -inserting an lvalue: -

      - -
      requires CopyConstructible<Cont::value_type>
-  back_insert_iterator<Cont>& 
-  operator=(const Cont::value_type& value);
-
      -
      --1- Effects: push_back(*container, Cont::value_type(value)); -
      -
      - -

      -The reason is to convert value into an rvalue because the current -BackInsertionContainer concept only handles push_back-ing -rvalues: -

      - -
      concept BackInsertionContainer<typename C> : Container<C> { 
-  void push_back(C&, value_type&&); 
-}
-
      - -

      -Without the conversion of value to an rvalue, the assignment operator -fails to concept check. -

      - -

      -A solution is to modify the BackInsertionContainer concept so that -the client can pass in the parameter type for push_back similar to -what is already done for the OutputIterator concept: -

      - -
      concept BackInsertionContainer<typename C, typename Value = C::value_type&&>
-  : Container<C> { 
-     void push_back(C&, Value); 
-}
-
      - -

      -This allows the assignment operator to be adjusted appropriately: -

      - -
      requires BackInsertionContainer<Cont, Cont::value_type const&> &&
-         CopyConstructible<Cont::value_type>
-  back_insert_iterator<Cont>& 
-  operator=(const Cont::value_type& value);
-
      -
      --1- Effects: push_back(*container, value); -
      -
      - -

      [ -We may want to propagate this fix to other concepts such as StackLikeContainer. -]

      - - -

      [ -Solution and wording collaborated on by Doug and Howard. -]

      - - -

      [ -Batavia (2009-05): -]

      - -
      -

      -Howard notes that "these operations behaved efficiently until concepts were added." -

      -

      -Alisdair is uncertain that the proposed resolution is syntactically correct. -

      -

      -Move to Open, and recommend the issue be deferred until after the next -Committee Draft is issued. -

      -
      - - -

      Proposed resolution:

      -

      -Change 23.2.6.1 [container.concepts.free]: -

      - -
      -
      concept FrontInsertionContainer<typename C, typename Value = C::value_type&&>
-    : Container<C> { 
-  void push_front(C&, value_type&& Value); 
-
-  axiom FrontInsertion(C c, value_type Value x) { 
-    x == (push_front(c, x), front(c)); 
-  } 
-}
-
      - -

      ...

      - -
      concept BackInsertionContainer<typename C, typename Value = C::value_type&&>
-    : Container<C> { 
-  void push_back(C&, value_type&& Value); 
-}
-
      - -

      ...

      - -
      concept InsertionContainer<typename C, typename Value = C::value_type&&>
-    : Container<C> { 
-  iterator insert(C&, const_iterator, value_type&& Value); 
-
-  axiom Insertion(C c, const_iterator position, value_type Value v) { 
-    v == *insert(c, position, v); 
-  } 
-}
-
      - -
      - -

      -Change 23.2.6.2 [container.concepts.member]: -

      - -
      -
      auto concept MemberFrontInsertionContainer<typename C, typename Value = C::value_type&&>
-    : MemberContainer<C> { 
-  void C::push_front(value_type&& Value); 
-
-  axiom MemberFrontInsertion(C c, value_type Value x) { 
-    x == (c.push_front(x), c.front()); 
-  } 
-}
-
      - -

      ...

      - -
      auto concept MemberBackInsertionContainer<typename C, typename Value = C::value_type&&>
-    : MemberContainer<C> { 
-  void C::push_back(value_type&& Value); 
-}
-
      - -

      ...

      - -
      auto concept MemberInsertionContainer<typename C, typename Value = C::value_type&&>
-    : MemberContainer<C> { 
-  iterator C::insert(const_iterator, value_type&& Value); 
-
-  axiom MemberInsertion(C c, const_iterator position, value_type Value v) { 
-    v == *c.insert(position, v); 
-  } 
-}
-
      -
      - -

      -Change 23.2.6.3 [container.concepts.maps]: -

      - -
      -
      template <MemberFrontInsertionContainer C, typename Value = C::value_type&&> 
-concept_map FrontInsertionContainer<C, Value> { 
-  typedef Container<C>::value_type value_type;
-
-  void push_front(C& c, value_type&& Value v) { c.push_front(static_cast<value_type&& Value>(v)); } 
-}
-
      - -

      ...

      - -
      template <MemberBackInsertionContainer C, typename Value = C::value_type&&> 
-concept_map BackInsertionContainer<C, Value> { 
-  typedef Container<C>::value_type value_type;
-
-  void push_back(C& c, value_type&& Value v) { c.push_back(static_cast<value_type&& Value>(v)); } 
-}
-
      - -

      ...

      - -
      template <MemberInsertionContainer C, typename Value = C::value_type&&> 
-concept_map InsertionContainer<C, Value> { 
-  typedef Container<C>::value_type value_type;
-  Container<C>::iterator insert(C& c, Container<C>::const_iterator i, value_type&& Value v) 
-  { return c.insert(i, static_cast<value_type&& Value>(v)); } 
-}
-
      - -
      - -

      -Change 24.7.1 [back.insert.iterator]: -

      - -
      template <BackInsertionContainer Cont> 
-class back_insert_iterator {
-  ...
-  requires BackInsertionContainer<Cont, const Cont::value_type&>
-           CopyConstructible<Cont::value_type>
-    back_insert_iterator<Cont>& 
-      operator=(const Cont::value_type& value);
-  ...
-
      - -

      -Change 24.7.2.2 [back.insert.iter.op=]: -

      - -
      -
      requires BackInsertionContainer<Cont, const Cont::value_type&>
-         CopyConstructible<Cont::value_type>
-  back_insert_iterator<Cont>& 
-    operator=(const Cont::value_type& value);
-
      -
      --1- Effects: push_back(*container, Cont::value_type(value)); -
      -
      - -

      -Change 24.7.3 [front.insert.iterator]: -

      - -
      template <FrontInsertionContainer Cont> 
-class front_insert_iterator {
-  ...
-  requires FrontInsertionContainer<Cont, const Cont::value_type&>
-           CopyConstructible<Cont::value_type>
-    front_insert_iterator<Cont>& 
-      operator=(const Cont::value_type& value);
-  ...
-
      - -

      -Change 24.7.4.2 [front.insert.iter.op=]: -

      - -
      -
      requires FrontInsertionContainer<Cont, const Cont::value_type&>
-         CopyConstructible<Cont::value_type>
-  front_insert_iterator<Cont>& 
-    operator=(const Cont::value_type& value);
-
      -
      --1- Effects: push_front(*container, Cont::value_type(value)); -
      -
      - -

      -Change 24.7.5 [insert.iterator]: -

      - -
      template <InsertionContainer Cont> 
-class insert_iterator {
-  ...
-  requires InsertionContainer<Cont, const Cont::value_type&>
-           CopyConstructible<Cont::value_type>
-    insert_iterator<Cont>& 
-      operator=(const Cont::value_type& value);
-  ...
-
      - -

      -Change 24.7.6.2 [insert.iter.op=]: -

      - -
      -
      requires InsertionContainer<Cont, const Cont::value_type&>
-         CopyConstructible<Cont::value_type>
-  insert_iterator<Cont>& 
-    operator=(const Cont::value_type& value);
-
      -
      -

      --1- Effects: -

      -
      iter = insert(*container, iter, Cont::value_type(value)); 
-++iter;
-
      -
      -
      - - - - - -

      978. Hashing smart pointers

      -

      Section: 20.7.17 [unord.hash] Status: Open - Submitter: Alisdair Meredith Opened: 2009-02-02 Last modified: 2009-07-28

      +

      Section: 20.7.16 [unord.hash] Status: Ready + Submitter: Alisdair Meredith Opened: 2009-02-02 Last modified: 2009-10-27

      View other active issues in [unord.hash].

      View all other issues in [unord.hash].

      -

      View all issues with Open status.

      +

      View all issues with Ready status.

      Discussion:

      +

      Addresses UK 208

      I don't see an open issue on supporting std::hash for smart pointers (unique_ptr and shared_ptr at least). @@ -21548,6 +14535,15 @@ This hash function makes sense in certain situations for shared_ptr ]

      +

      [ +2009-10 Santa Cruz: +]

      + + +
      +Move to Ready. +
      +

      Proposed resolution:

      @@ -21575,7 +14571,7 @@ Add a new subclause 20.8.10.X hash support
      -A partial specialization of the class template hash (20.7.17 [unord.hash]) shall be provided for instances of the +A partial specialization of the class template hash (20.7.16 [unord.hash]) shall be provided for instances of the unique_ptr template suitable for use as a key in unordered associative containers (23.5 [unord]) if and only if there is a hash specialization available for the type D::pointer. @@ -21588,7 +14584,7 @@ D::pointer>{}(p.get()).
      -A partial specialization of the class template hash (20.7.17 [unord.hash]) +A partial specialization of the class template hash (20.7.16 [unord.hash]) shall be provided for instances of the shared_ptr template suitable for use as a key in unordered associative containers (23.5 [unord]). For an object p of type shared_ptr<T> @@ -21603,11 +14599,11 @@ to the same value as hash<T*>{}(p.get()).

      983. unique_ptr reference deleters should not be moved from

      -

      Section: 20.8.9.2 [unique.ptr.single] Status: Review - Submitter: Howard Hinnant Opened: 2009-02-10 Last modified: 2009-05-23

      +

      Section: 20.8.14.2 [unique.ptr.single] Status: Ready + Submitter: Howard Hinnant Opened: 2009-02-10 Last modified: 2009-10-21

      View other active issues in [unique.ptr.single].

      View all other issues in [unique.ptr.single].

      -

      View all issues with Review status.

      +

      View all issues with Ready status.

      Discussion:

      Dave brought to my attention that when a unique_ptr has a non-const reference @@ -21639,10 +14635,20 @@ Batavia (2009-05): Seems correct, but complicated enough that we recommend moving to Review.

      +

      [ +2009-10 Santa Cruz: +]

      + + +
      +Move to Ready. +
      + +

      Proposed resolution:

      -Change 20.8.9.2.1 [unique.ptr.single.ctor], p20-21 +Change 20.8.14.2.1 [unique.ptr.single.ctor], p20-21

      @@ -21684,7 +14690,7 @@ note]

      -Change 20.8.9.2.3 [unique.ptr.single.asgn], p1-3 +Change 20.8.14.2.3 [unique.ptr.single.asgn], p1-3

      @@ -21716,7 +14722,7 @@ move assigned. -- end note]

      -Change 20.8.9.2.3 [unique.ptr.single.asgn], p6-7 +Change 20.8.14.2.3 [unique.ptr.single.asgn], p6-7

      @@ -21756,7 +14762,7 @@ deleter participates in the move assignment.

      985. Allowing throwing move

      Section: 23.2.1 [container.requirements.general] Status: Open - Submitter: Rani Sharoni Opened: 2009-02-12 Last modified: 2009-05-23

      + Submitter: Rani Sharoni Opened: 2009-02-12 Last modified: 2009-10-20

      View other active issues in [container.requirements.general].

      View all other issues in [container.requirements.general].

      View all issues with Open status.

      @@ -21887,6 +14893,17 @@ Committee Draft is issued.

      +

      [ +2009-10 Santa Cruz: +]

      + + +
      +Should wait to get direction from Dave/Rani +(N2983). +
      + +

      Proposed resolution:

      @@ -22034,10 +15051,10 @@ constructor, move constructor or assignment operator of T.

      987. reference_wrapper and function types

      -

      Section: 20.7.5 [refwrap] Status: Open - Submitter: Howard Hinnant Opened: 2009-02-18 Last modified: 2009-07-14

      +

      Section: 20.7.5 [refwrap] Status: Tentatively Ready + Submitter: Howard Hinnant Opened: 2009-02-18 Last modified: 2009-10-26

      View all other issues in [refwrap].

      -

      View all issues with Open status.

      +

      View all issues with Tentatively Ready status.

      Discussion:

      The synopsis in 20.7.5 [refwrap] says: @@ -22196,56 +15213,34 @@ Moved from Review to Open only because the wording needs to be tweaked for concepts removal.

      +

      [ +2009-10-14 Daniel provided de-conceptified wording. +]

      + + +

      [ +2009-10 post-Santa Cruz: +]

      + + +
      +Move to Tentatively Ready. +
      +

      Proposed resolution:

      -Change the synopsis in 20.7 [function.objects]: +Change 20.7.5 [refwrap]/1 as indicated:

      -
      // 20.6.5, reference_wrapper:
-template <ObjectType ReferentType T>
-  requires PointeeType<T>
-  class reference_wrapper;
+
      
+reference_wrapper<T> is a CopyConstructible and
+CopyAssignable wrapper around a
+reference to an object or function of type T.
+
      
 
-template <ObjectType PointeeType T>
-  reference_wrapper<T> ref(T&);
 
-template <ObjectType PointeeType T>
-  reference_wrapper<const T> cref(const T&);
-
-template <ObjectType PointeeType T>
-  reference_wrapper<T> ref(reference_wrapper<T>);
-template <ObjectType PointeeType T>
-  reference_wrapper<const T> cref(reference_wrapper<T>);
-
      - -

      -Change the synopsis in 20.7.5 [refwrap]: -

      - -
      template <ObjectType ReferentType T>
-  requires PointeeType<T>
-  class reference_wrapper
-   ...
-
      - -

      -Change the prototypes in 20.7.5.5 [refwrap.helpers]: -

      - -
      template <ObjectType PointeeType T>
-  reference_wrapper<T> ref(T&);
-...
-template <ObjectType PointeeType T>
-  reference_wrapper<const T> cref(const T&);
-...
-template <ObjectType PointeeType T>
-  reference_wrapper<T> ref(reference_wrapper<T>);
-...
-template <ObjectType PointeeType T>
-  reference_wrapper<const T> cref(reference_wrapper<T>);
-
      @@ -22253,12 +15248,12 @@ template <ObjectType PointeeType T>

      a) The occurrence of T& in the function signature auto-implies std::ReferentType, -this is due to 14.11.1.2 [temp.req.impl]/4 bullet 4 +this is due to [temp.req.impl]/4 bullet 4

      b) The occurrence of the constrained template reference_wrapper<T> in the remaining -signatures lets kick in 14.11.1.2 [temp.req.impl]/4 bullet 1 and adds *all* requirements of +signatures lets kick in [temp.req.impl]/4 bullet 1 and adds *all* requirements of this template. But we need to add at least *one* requirement (and it was an arbitrary, but natural decision to require std::PointeeType here) to *activate* @@ -22307,10 +15302,10 @@ review.

      999. Taking the address of a function

      -

      Section: 20.8.8.1 [object.addressof] Status: Open - Submitter: Peter Dimov Opened: 2009-03-09 Last modified: 2009-07-14

      -

      View all other issues in [object.addressof].

      -

      View all issues with Open status.

      +

      Section: 20.8.13 [specialized.algorithms] Status: Tentatively Ready + Submitter: Peter Dimov Opened: 2009-03-09 Last modified: 2009-10-26

      +

      View all other issues in [specialized.algorithms].

      +

      View all issues with Tentatively Ready status.

      Discussion:

      The same fix (reference 987) may be applied to addressof, which is also constrained to @@ -22344,100 +15339,60 @@ Moved from Tentatively Ready to Open only because the wording needs to be tweaked for concepts removal. +

      [ +2009-10-10 Daniel updates wording to concept-free. +]

      + + +

      [ +2009-10 post-Santa Cruz: +]

      + + +
      +Move to Tentatively Ready. +
      +

      Proposed resolution:

      -

      -Change the synopsis in 20.8 [memory]: -

      +

      [ +The resolution assumes that addressof is reintroduced as described in +n2946 +]

      -
      template <ObjectType PointeeType T>
-  T* addressof(T& r);
-

      -Change 20.8.8.1 [object.addressof]: +In 20.8.13 [specialized.algorithms] change as described:

      -
      template <ObjectType PointeeType T>
-  T* addressof(T& r);
-
      +
      template <class T> T* addressof(T& r);
+
      +
      +Returns: The actual address of the object or function +referenced by r, even in the +presence of an overloaded operator&. +
      +
      + +

      Rationale:

      a) The occurrence of T& in the function signature auto-implies std::ReferentType, -this is due to 14.11.1.2 [temp.req.impl]/4 bullet 4 +this is due to [temp.req.impl]/4 bullet 4

      -
      -

      1004. Response to UK 179

      -

      Section: 17.6.3.8 [res.on.functions] Status: Ready - Submitter: Alisdair Meredith Opened: 2009-03-11 Last modified: 2009-07-18

      -

      View all other issues in [res.on.functions].

      -

      View all issues with Ready status.

      -

      Discussion:

      - -

      Addresses UK 179

      - -

      -According to the 4th bullet there is a problem if "if any replacement -function or handler function or destructor operation throws an -exception". There should be no problem throwing exceptions so long as -they are caught within the function. -

      - -

      [ -Batavia (2009-05): -]

      - -
      -The phrasing "throws an exception" is commonly used elsewhere -to mean "throws or propagates an exception." -Move to Open pending a possible more general resolution. -
      - -

      [ -2009-07 Frankfurt: -]

      - - -
      -Replace "propagates" in the proposed resolution with the phrase "exits -via" and move to Ready. -
      - - - -

      Proposed resolution:

      -

      -Change the 4th bullet of 17.6.3.8 [res.on.functions], p2: -

      - -
      -
        -
      • -if any replacement function or handler function or destructor operation -throws exits via an exception, unless specifically -allowed in the applicable Required behavior: paragraph. -
        • -
      -
      - - - - - -

      1008. nested_exception wording unclear

      Section: 18.8.6 [except.nested] Status: Open - Submitter: Alisdair Meredith Opened: 2009-03-11 Last modified: 2009-07-04

      + Submitter: Alisdair Meredith Opened: 2009-03-11 Last modified: 2009-10-22

      View other active issues in [except.nested].

      View all other issues in [except.nested].

      View all issues with Open status.

      @@ -22459,157 +15414,18 @@ Alisdair will add an example in an update to N2619. - - -

      Proposed resolution:

      - - - - - -
      -

      1009. InputIterator post-increment dangerous

      -

      Section: 24.2.1 [iterator.iterators] Status: Open - Submitter: Alisdair Meredith Opened: 2009-03-11 Last modified: 2009-07-28

      -

      View all issues with Open status.

      -

      Discussion:

      - -

      Addresses UK 251

      - -

      -The post-increment operator is dangerous for a general InputIterator. -The multi-pass guarantees that make it meaningful are defined as part of -the ForwardIterator refinement. Any change will affect only constrained -templates that have not yet been written, so should not break existing -user iterators which remain free to add these operations. This change -will also affect the generalised OutputIterator, although there is no -percieved need for the post-increment operator in this case either. -

      -

      [ -2009-07-28 Alisdair adds: +2009-10 Santa Cruz: ]

      -We still think the issue is relevant, but needs totally rewording in -non-concept language. We would like to see the issue retained as Open, -rather than deferred as NAD Concepts. Review status is no longer -appropriate. +It doesn't appear that N2619 really addresses this. Alisdair to propose wording.

      Proposed resolution:

      -

      -Change 24.2.1 [iterator.iterators]: -

      - -
      concept Iterator<typename X> : Semiregular<X> { 
-  MoveConstructible reference = typename X::reference; 
-  MoveConstructible postincrement_result;
-
-  requires HasDereference<postincrement_result>;
-
-  reference operator*(X&&); 
-  X& operator++(X&); 
-  postincrement_result operator++(X&, int);
-}
-
      - -

      ...

      -
      postincrement_result operator++(X& r, int);
-
      - -
      --3- Effects: equivalent to { X tmp = r; ++r; return tmp; }. -
      - -
      - -

      -Change 24.2.2 [input.iterators]: -

      - -
      -
      concept InputIterator<typename X> : Iterator<X>, EqualityComparable<X> { 
-  ObjectType value_type = typename X::value_type; 
-  MoveConstructible pointer = typename X::pointer; 
-
-  SignedIntegralLike difference_type = typename X::difference_type; 
-
-  requires IntegralType<difference_type> 
-        && Convertible<reference, const value_type &>; 
-        && Convertible<pointer, const value_type*>; 
-
-  requires Convertible<HasDereference<postincrement_result>::result_type, const value_type&>;
-
-  pointer operator->(const X&); 
-}
-
      -
      - -

      -Change 24.2.3 [output.iterators]: -

      - -
      -
      auto concept OutputIterator<typename X, typename Value> { 
-  requires Iterator<X>; 
-
-  typename reference = Iterator<X>::reference; 
-  typename postincrement_result = Iterator<X>::postincrement_result;
-  requires SameType<reference, Iterator<X>::reference> 
-        && SameType<postincrement_result, Iterator<X>::postincrement_result>
-        && Convertible<postincrement_result, const X&>
-        && HasAssign<reference, Value> 
-        && HasAssign<HasDereference<postincrement_result>::result_type, Value>;
-}
-
      -
      - -

      -Change 24.2.4 [forward.iterators]: -

      - -

      [ -See 1084 which is attempting to change this same area in a compatible -way. -]

      - - -
      -
      concept ForwardIterator<typename X> : InputIterator<X>, Regular<X> { 
-  requires Convertible<postincrement_result, const X&>;
-
-  MoveConstructible postincrement_result;
-  requires HasDereference<postincrement_result>
-        && Convertible<HasDereference<postincrement_result>::result_type, const value_type&>;
-
-  postincrement_result operator++(X&, int);
-
-  axiom MultiPass(X a, X b) { 
-    if (a == b) *a == *b; 
-    if (a == b) ++a == ++b; 
-  } 
-}
-
      - -
      -

      -4- ...

      -
      - -
      postincrement_result operator++(X& r, int);
-
      - -
      -

      --5- Effects: equivalent to { X tmp = r; ++r; return tmp; }. -

      -
      - -
      - @@ -22617,11 +15433,11 @@ way.

      1011. next/prev wrong iterator type

      -

      Section: 24.4 [iterator.operations] Status: Open - Submitter: Alisdair Meredith Opened: 2009-03-11 Last modified: 2009-07-14

      +

      Section: 24.4.4 [iterator.operations] Status: Ready + Submitter: Alisdair Meredith Opened: 2009-03-11 Last modified: 2009-10-22

      View other active issues in [iterator.operations].

      View all other issues in [iterator.operations].

      -

      View all issues with Open status.

      +

      View all issues with Ready status.

      Discussion:

      Addresses UK 271

      @@ -22652,288 +15468,61 @@ Moved from Tentatively Ready to Open only because the wording needs to be tweaked for concepts removal. +

      [ +2009-10-14 Daniel provided de-conceptified wording. +]

      -

      Proposed resolution:

      -

      -Change [iterator.synopsis]: -

      - -
      template <InputIterator ForwardIterator Iter> 
-  Iter next(Iter x, 
-    Iter::difference_type n = 1);
-
      - -

      -Change 24.4 [iterator.operations], p6: -

      - -
      template <InputIterator ForwardIterator Iter> 
-  Iter next(Iter x, 
-    Iter::difference_type n = 1);
-
      - - - - - - -
      -

      1012. reverse_iterator default ctor should value initialize

      -

      Section: 24.5.1.2.1 [reverse.iter.cons] Status: Tentatively Ready - Submitter: Alisdair Meredith Opened: 2009-03-11 Last modified: 2009-07-18

      -

      View all issues with Tentatively Ready status.

      -

      Discussion:

      - -

      Addresses UK 277

      - -

      -The default constructor default-initializes current, rather than -value-initializes. This means that when Iterator corresponds to a -trivial type, the current member is left un-initialized, even when the -user explictly requests value intialization! At this point, it is not -safe to perform any operations on the reverse_iterator other than assign -it a new value or destroy it. Note that this does correspond to the -basic definition of a singular iterator. -

      -

      [ -Summit: +2009-10 Santa Cruz: ]

      -Agree with option i. -
      - -

      -Related issue: 408 -

      - -

      [ -Batavia (2009-05): -]

      - -
      -We believe this should be revisited -in conjunction with issue 408, -which nearly duplicates this issue. -Move to Open. -
      - -

      [ -2009-07 post-Frankfurt: -]

      - - -
      -

      -Change "constructed" to "initialized" in two places in the proposed resolution. -

      -

      -Move to Tentatively Ready. -

      +Moved to Ready.

      Proposed resolution:

      + + +
        +

      1. -Change [reverse.iter.con]: +Change header <iterator> synopsis 24.3 [iterator.synopsis] as indicated:

        -
        reverse_iterator();
-
        -
        --1- Effects: Default Value initializes current. Iterator -operations applied to the resulting iterator have defined behavior if and -only if the corresponding operations are defined on a default constructed -value initialized -iterator of type Iterator. -
        -
        - -

        -Change 24.5.2.2.1 [move.iter.op.const]: -

        - -
        move_iterator();
-
        -
        --1- Effects: Constructs a move_iterator, default value -initializing current. -Iterator -operations applied to the resulting iterator have defined behavior if and -only if the corresponding operations are defined on a -value initialized -iterator of type Iterator. -
        -
        - - - - - - -
        -

        1019. Response to UK 205

        -

        Section: 20.6.3 [meta.help] Status: Tentatively Ready - Submitter: Alisdair Meredith Opened: 2009-03-11 Last modified: 2009-07-18

        -

        View all other issues in [meta.help].

        -

        View all issues with Tentatively Ready status.

        -

        Discussion:

        - -

        Addresses UK 205

        - -

        -integral_constant objects should be usable in integral-constant-expressions. -The addition to the language of literal types and the enhanced rules for -constant expressions make this possible. -

        - -

        [ -Batavia (2009-05): -]

        - -
        -We agree that the static data member -ought be declared constexpr, -but do not see a need for the proposed operator value_type(). -(A use case would be helpful.) -Move to Open. -
        - -

        [ -2009-05-23 Alisdair adds: -]

        - - -
        -

        -The motivating case in my mind is that we can then use -true_type and false_type as integral Boolean expressions, for example inside -a static_assert declaration. In that sense it is purely a matter of style. -

        -

        -Note that Boost has applied the non-explicit conversion operator for many -years as it has valuable properties for extension into other metaprogramming -libraries, such as MPL. If additional rationale is desired I will poll the -Boost lists for why this extension was originally applied. I would argue -that explicit conversion is more appropriate for 0x though. -

        -
        - -

        [ -2009-07-04 Howard adds: -]

        - - -
        -

        -Here's a use case which demonstrates the syntactic niceness which Alisdair describes: -

        - -
        #define requires(...) class = typename std::enable_if<(__VA_ARGS__)>::type
-
-template <class T, class U,
-    requires(!is_lvalue_reference<T>() ||
-              is_lvalue_reference<T>() && is_lvalue_reference<U>()),
-    requires(is_same<typename base_type<T>::type,
-                     typename base_type<U>::type>)>
-inline
-T&&
-forward(U&& t)
-{
-    return static_cast<T&&>(t);
-}
+
        // 24.4.4, iterator operations:
+...
+template <class InputForwardIterator>
+  InputForwardIterator
+  next(InputForwardIterator x, typename std::iterator_traits<InputForwardIterator>::difference_type n = 1);
 
        
-
        +
        2. -

        [ -2009-07 post-Frankfurt: -]

        - - -
        -Move to Tentatively Ready. -
        - - - -

        Proposed resolution:

        +

      2. -Add to the integral_constant struct definition in 20.6.3 [meta.help]: +Change 24.4.4 [iterator.operations] before p.6 as indicated:

        -
        template <class T, T v>
-struct integral_constant {
-  static constexpr T value = v;
-  typedef T value_type;
-  typedef integral_constant<T,v> type;
-  constexpr operator value_type() { return value; }
-};
+
        template <class InputForwardIterator>
+  InputForwardIterator
+  next(InputForwardIterator x, typename std::iterator_traits<InputForwardIterator>::difference_type n = 1);
 
        
+
        3. +
      -
      -

      1020. Response to UK 204

      -

      Section: 20.6.7 [meta.trans.other] Status: Open - Submitter: Alisdair Meredith Opened: 2009-03-11 Last modified: 2009-03-12

      -

      View other active issues in [meta.trans.other].

      -

      View all other issues in [meta.trans.other].

      -

      View all issues with Open status.

      -

      Discussion:

      - -

      Addresses UK 204

      - -

      -It is not possible to create a variant union based on a parameter pack -expansion, e.g. to implement a classic discriminated union template. -

      - -

      Original proposed resolutuion:

      - -

      -Restore aligned_union template that was removed by LWG issue 856. -

      - -

      [ -Summit: -]

      - - -
      -Agree. The need for aligned_union is compelling enough to reinstate. -
      - -

      [ -Post Summit, Alisdair adds: -]

      - - -
      -paper -N2843 -proposes an extension to the [[align]] attribute -that further diminishes the need for this template. Recommend NAD. -
      - - - -

      Proposed resolution:

      - - - -

      1030. Response to JP 44

      -

      Section: 20.8.10.6 [util.smartptr.shared.atomic] Status: Open - Submitter: Alisdair Meredith Opened: 2009-03-11 Last modified: 2009-07-18

      -

      View all issues with Open status.

      +

      Section: 20.8.15.5 [util.smartptr.shared.atomic] Status: Ready + Submitter: Alisdair Meredith Opened: 2009-03-11 Last modified: 2009-10-23

      +

      View all issues with Ready status.

      Discussion:

      Addresses JP 44

      @@ -22976,121 +15565,46 @@ Lawrence to write wording that requires that the pointers not be null.

      - - -

      Proposed resolution:

      - - - - - -
      -

      1031. Response to US 78

      -

      Section: 20.8.10.2 [util.smartptr.shared] Status: Tentatively NAD Future - Submitter: Alisdair Meredith Opened: 2009-03-11 Last modified: 2009-07-26

      -

      View other active issues in [util.smartptr.shared].

      -

      View all other issues in [util.smartptr.shared].

      -

      View all issues with Tentatively NAD Future status.

      -

      Discussion:

      - -

      Addresses US 78

      - -

      -There is presently no way to convert directly from a shared_ptr to a -unique_ptr. Add an interface that performs the conversion. -

      -

      [ -Summit: -]

      - - -
      -We look forward to a paper on this topic. We recommend no action until a -paper is available. We believe that the shared pointer must use the default -deleter for the conversion to succeed. -
      - -

      [ -Peter Dimov adds: -]

      - - -
      -This is basically a request for shared_ptr<>::release in -disguise, with all the associated problems. Not a good idea. -
      - -

      [ -2009-07 post-Frankfurt: +2009-09-20 Lawrence provided wording: ]

      -The rationale for the omission of a release() member function from shared_ptr is given in: -http://www.boost.org/doc/libs/1_39_0/libs/smart_ptr/shared_ptr.htm +The parameter types for atomic shared pointer access +were deliberately chosen to be pointers +to match the corresponding parameters of the atomics chapter. +Those in turn were deliberately chosen +to match C functions, +which do not have reference parameters.

      -The implementation of such a member is non-trivial (and maybe -impossible), because it would need to account for the deleter. +We adopt the second suggestion, +to require that such pointers not be null.

      [ -2009-07-26 Howard sets to Tentatively NAD Future. +2009-10 Santa Cruz: ]

      -

      -I took an online poll and got 3 votes for NAD and 3 for NAD Future. Personally -I prefer NAD Future as this does refer to an extension that could conceivably be -considered beyond C++0X. -

      - -

      -However such an extension would need to solve a couple of problems: -

      - -
        -
      1. What is the interface for such a conversion when the shared_ptr does -not have unique ownership? Throw an exception? Create a null unique_ptr? -Undefined behavior? -
        2. - -
      2. -

        -How does one handle custom deleters given to the shared_ptr constructor? -

        -

        -I do not believe it is possible to implement a general answer to this question. -The shared_ptr deleter is a run time (or construction time) characteristic. -The unique_ptr deleter is a compile time characteristic. In general one -can not know to what type of unqiue_ptr you are converting to. -

        -

        -One answer is for the user of the conversion to specify the deleter type and perhaps -throw an exception if the specification turns out to be incorrect. -

        -

        -Another answer is for the conversion to only be valid when the underlying deleter -is default_delete. We would probalby need to specify that this is indeed the -underlying deleter of a shared_ptr when a custom deleter is not given in -the constructor. -

        -
        3. -
      - -

      -At any rate, there are non-trivial design issues which would need to be implemented -and tested in the field for usability prior to standardization. -

      +Moved to Ready.

      Proposed resolution:

      +

      +In section "shared_ptr atomic access" +20.8.15.5 [util.smartptr.shared.atomic], add to each function the +following clause. +

      +

      +Requires: p shall not be null. +

      @@ -23188,7 +15702,7 @@ Move to Open.

      1034. Response to UK 222

      Section: 23.2.1 [container.requirements.general] Status: Open - Submitter: Alisdair Meredith Opened: 2009-03-12 Last modified: 2009-07-18

      + Submitter: Alisdair Meredith Opened: 2009-03-12 Last modified: 2009-10-20

      View other active issues in [container.requirements.general].

      View all other issues in [container.requirements.general].

      View all issues with Open status.

      @@ -23244,1037 +15758,14 @@ the issue should be closed as NAD unless a proposed resolution is submitted prior to the March 2010 meeting. - - -

      Proposed resolution:

      - - - - - -
      -

      1035. Response to UK 226

      -

      Section: 23.2.1 [container.requirements.general] Status: Open - Submitter: Alisdair Meredith Opened: 2009-03-12 Last modified: 2009-08-01

      -

      View other active issues in [container.requirements.general].

      -

      View all other issues in [container.requirements.general].

      -

      View all issues with Open status.

      -

      Discussion:

      - -

      Addresses UK 226

      - -

      -<array> must be added to this list. In particular it -doesn't satisfy: - no swap() function invalidates any -references, pointers, or iterators referring to the elements of the -containers being swapped. and probably doesn't satisfy: - no -swap() function throws an exception. -

      -

      -If <array> remains a container, this will have to also -reference array, which will then have to say which of these -points it satisfies. -

      -

      [ -Summit: +2009-10 Santa Cruz: ]

      -Agree. The proposed resolution is incomplete. Further work required. -
      - -

      [ -2009-05-01 Daniel adds: -]

      - - -
      -Issue 1099 also suggests -adding move constructor to this. -
      - -

      [ -2009-07 post-Frankfurt: -]

      - - -
      -Howard is to draft a note that explains what happens to references. -
      - - - -

      [ -2009-08-01 Howard provided wording. -]

      - - -

      Proposed resolution:

      -

      -Add a paragraph to 23.3.1.2 [array.special]: -

      - -
      template <Swappable T, size_t N> void swap(array<T,N>& x, array<T,N>& y);
-
      -
      -

      -Effects: -

      -
      swap_ranges(x.begin(), x.end(), y.begin());
-
      - -

      -[Note: -Outstanding iterators, references and pointers may be invalidated. -— end note] -

      -
      -
      - - - - - -
      -

      1041. Response to UK 239

      -

      Section: 23.2.4 [associative.reqmts] Status: Open - Submitter: Alisdair Meredith Opened: 2009-03-12 Last modified: 2009-07-18

      -

      View all other issues in [associative.reqmts].

      -

      View all issues with Open status.

      -

      Discussion:

      - -

      Addresses UK 239

      - -

      -It is not possible to take a move-only key out of an unordered -container, such as (multi)set or -(multi)map, or the new unordered containers. -

      - -

      -Add below a.erase(q), a.extract(q), with the following notation: -

      -

      -a.extract(q)>, Return type pair<key, iterator> -Extracts the element pointed to by q and erases it from the -set. Returns a pair containing the value pointed to by -q and an iterator pointing to the element immediately -following q prior to the element being erased. If no such -element exists,returns a.end(). -

      - -

      [ -Summit: -]

      - - -
      -We look forward to a paper on this topic. We recommend no action until a -paper is available. The paper would need to address exception safety. -
      - -

      [ -Post Summit Alisdair adds: -]

      - - -
      -Would value_type be a better return type than key_type? -
      - -

      [ -2009-07 post-Frankfurt: -]

      - - -
      -Leave Open. Alisdair to contact Chris Jefferson about this. -
      - - - -

      Proposed resolution:

      -

      -In 23.2.4 [associative.reqmts] Table 85, add: -

      - -
      - - - - - - - - - - - - - - - - - - -
      Table 85 -- Associative container requirements (in addition to container)
      ExpressionReturn typeAssertion/note
      pre-/post-condition      		Complexity
      a.erase(q).........
      a.extract(q)pair<key_type, iterator>Extracts the element pointed to by q and erases it from the set. -Returns a pair containing the value pointed to by q and an iterator -pointing to the element immediately following q prior to the element being -erased. If no such element -exists, returns a.end().amortized constant
      -
      - -

      -In 23.2.5 [unord.req] Table 87, add: -

      - -
      - - - - - - - - - - - - - - - - - - -
      Table 87 -- Unordered associative container requirements (in addition to container)
      ExpressionReturn typeAssertion/note
      pre-/post-condition      		Complexity
      a.erase(q).........
      a.extract(q)pair<key_type, iterator>Extracts the element pointed to by q and erases it from the set. -Returns a pair containing the value pointed to by q and an iterator -pointing to the element immediately following q prior to the element being -erased. If no such element -exists, returns a.end().amortized constant
      -
      - - - - - -
      -

      1042. Response to UK 244

      -

      Section: 23.3 [sequences] Status: Open - Submitter: Alisdair Meredith Opened: 2009-03-12 Last modified: 2009-07-18

      -

      View all other issues in [sequences].

      -

      View all issues with Open status.

      -

      Discussion:

      - -

      Addresses UK 244

      - -

      -The validity of the expression &a[n] == &a[0] + n is contingent on -operator& doing the "right thing" (as captured by the CopyConstructible -requirements in table 30 in C++2003). However this constraint has been -lost in the Concepts of C++0x. This applies to vector and array (it -actually applies to string also, but that's a different chapter, so I'll -file a separate comment there and cross-reference). -

      - -

      -Suggested solution: -

      - -

      -Define a ContiguousStrorage and apply it to -vector, array and string. -

      - -

      [ -Summit: -]

      - - -
      -Agree with the issue but not the details of the proposed solution. Walter to -provide wording for the new concept. -
      - -

      [ -Post Summit Alisdair adds: -]

      - - -
      -Another LWG subgroup wondered if this concept -should extend to complex<T>, and so not be built on the container concept at -all? -
      - -

      [ -2009-07 post-Frankfurt: -]

      - - -
      -Leave Open, pending a post-Concepts Working Draft. -
      - - - -

      Proposed resolution:

      -

      -Add to <container_concepts> synopsis in 23.2.6 [container.concepts] -

      - -
      concept< typename C > ContiguousStorageContainer see below;
-
      - -

      -Add a new section to the end of 23.2.6 [container.concepts] -

      - -
      -

      -23.1.6.x ContiguousStorageContainer concept [container.concepts.contiguous] -

      - -
      concept ContiguousStorageContainer< typename C >
-  : Container<C>
-{
-  value_type* data(C&);
-
-  axiom Contiguity(C& c, size_type i) {
-    if( i < size(c) ) {
-         addressof( * (data(c) + i) )
-      == addressof( * advance(data(c), i) );
-    }
-  }
-}
-
      - -

      -The ContiguousStorageContainer concept describes a container whose elements -are allocated in a single region of memory, and are stored sequentially -without intervening padding other than to meet alignment requirements. -For example, the elements may be stored in a -single array of suitable length. -

      - -
      value_type * data( C& );
-
      - -
      -Returns: a pointer to the first element in the region of storage. -Result is unspecified for an empty container. -
      - -
      - -

      -Change 23.3.1 [array] p1: -

      - -
      --1- The header <array> defines a class template for -storing fixed-size sequences of objects. An array supports -random access iterators. An instance of array<T, N> -stores N elements of type T, so that size() == -N is an invariant. The elements of an array are stored -contiguously, meaning that if a is an -array<T, N> then it obeys the identity &a[n] -== &a[0] + n for all 0 <= n < N -satisfies the concept ContiguousStorageContainer< array<T, -N>>. -
      - -

      -Add to the synopsis in 23.3.1 [array]: -

      - -
          ...
-    T * data(); 
-    const T * data() const; 
-  };
-
-  template< typename T, size_t N >
-    concept_map ContiguousStorageContainer< array<T, N>> {};
-} 
-
      - -

      -Change 23.3.6 [vector] p1: -

      - -
      -A vector is a sequence container that supports random access -iterators. In addition, it supports (amortized) constant time insert and -erase operations at the end; insert and erase in the middle take linear -time. Storage management is handled automatically, though hints can be -given to improve efficiency. The elements of a vector are stored -contiguously, meaning that if v is a -vector<T, Alloc> (where T is some -type other than bool), then it obeys the -identity &v[n] == &v[0] + n for all 0 <= n < -v.size() satisfies the concept ContiguousStorageContainer< -vector< T, Alloc>>. -
      - -

      -Add at the end of the synopsis in 23.3.6 [vector] p2: -

      - -
      template< typename T, typename A >
-  requires !SameType< T, bool >
-  concept_map ContiguousStorageContainer< vector<T, A>> {};
-
      - - - - - - -
      -

      1043. Response to US 91

      -

      Section: 29.6 [atomics.types.operations] Status: Review - Submitter: Alisdair Meredith Opened: 2009-03-12 Last modified: 2009-07-18

      -

      View other active issues in [atomics.types.operations].

      -

      View all other issues in [atomics.types.operations].

      -

      View all issues with Review status.

      -

      Discussion:

      - -

      Addresses US 91

      - -

      -It is unclear whether or not a failed compare_exchange is a RMW operation -(as used in 1.10 [intro.multithread]). -

      - -

      -Suggested solution: -

      - -

      -Make failing compare_exchange operations not be RMW. -

      - -

      [ -Anthony Williams adds: -]

      - - -
      -In 29.6 [atomics.types.operations] p18 it says that "These -operations are atomic read-modify-write operations" (final sentence). -This is overly restrictive on the implementations of -compare_exchange_weak and compare_exchange_strong on platforms without a -native CAS instruction. -
      - - -

      [ -Summit: -]

      - - -
      -Group agrees with the resolution as proposed by Anthony Williams in the attached note. -
      - -

      [ -Batavia (2009-05): -]

      - -
      -We recommend the proposed resolution be reviewed -by members of the Concurrency Subgroup. -
      - -

      [ -2009-07 post-Frankfurt: -]

      - - -
      -This is likely to be addressed by Lawrence's upcoming paper. He will -adopt the proposed resolution. -
      - - - -

      Proposed resolution:

      -

      -Change 29.6 [atomics.types.operations] p18: -

      - -
      --18- Effects: Atomically, compares the value pointed to by -object or by this for equality with that in -expected, and if true, replaces the value pointed to by -object or by this with desired, and if false, updates -the value in expected with the value pointed to by -object or by this. Further, if the comparison is true, -memory is affected according to the value of success, and if the -comparison is false, memory is affected according to the value of -failure. When only one memory_order argument is -supplied, the value of success is order, and the value -of failure is order except that a value of -memory_order_acq_rel shall be replaced by the value -memory_order_acquire and a value of -memory_order_release shall be replaced by the value -memory_order_relaxed. If the comparison is true, -Tthese operations are atomic -read-modify-write operations (1.10). -If the comparison is false, these -operations are atomic load operations. -
      - - - - - - -
      -

      1046. Response to UK 329

      -

      Section: 30.6 [futures] Status: Open - Submitter: Alisdair Meredith Opened: 2009-03-12 Last modified: 2009-03-13

      -

      View all issues with Open status.

      -

      Discussion:

      - -

      Addresses UK 329

      - -

      -future, promise and packaged_task provide a -framework for creating future values, but a simple function to tie all -three components together is missing. Note that we only need a *simple* -facility for C++0x. Advanced thread pools are to be left for TR2. -

      - -

      -Simple Proposal: -

      - -

      -Provide a simple function along the lines of: -

      -
      template< typename F, typename ... Args >
-  requires Callable< F, Args... >
-    future< Callable::result_type > async( F&& f, Args && ... ); 
-
      - -

      -Semantics are similar to creating a thread object with a packaged_task -invoking f with forward<Args>(args...) -but details are left unspecified to allow different scheduling and thread -spawning implementations. -

      -

      -It is unspecified whether a task submitted to async is run on its own thread -or a thread previously used for another async task. If a call to async -succeeds, it shall be safe to wait for it from any thread. -

      -

      -The state of thread_local variables shall be preserved during async calls. -

      -

      -No two incomplete async tasks shall see the same value of -this_thread::get_id(). -

      -

      -[Note: this effectively forces new tasks to be run on a new thread, or a -fixed-size pool with no queue. If the -library is unable to spawn a new thread or there are no free worker threads -then the async call should fail. --end note] -

      - -

      [ -Summit: -]

      - - -
      -

      -The concurrency subgroup has revisited this issue and decided that it -could be considered a defect according to the Kona compromise. A task -group was formed lead by Lawrence Crowl and Bjarne Stroustrup to write a -paper for Frankfort proposing a simple asynchronous launch facility -returning a future. It was agreed that the callable must be run on a -separate thread from the caller, but not necessarily a brand-new thread. -The proposal might or might not allow for an implementation that uses -fixed-size or unlimited thread pools. -

      -

      -Bjarne in c++std-lib-23121: I think that what we agreed was that to -avoid deadlock async() would almost certainly be specified to launch in -a different thread from the thread that executed async(), but I don't -think it was a specific design constraint. -

      -
      - - - -

      Proposed resolution:

      - - - - - -
      -

      1047. Response to UK 334

      -

      Section: 30.6.5 [futures.unique_future] Status: Review - Submitter: Alisdair Meredith Opened: 2009-03-12 Last modified: 2009-05-23

      -

      View other active issues in [futures.unique_future].

      -

      View all other issues in [futures.unique_future].

      -

      View all issues with Review status.

      -

      Discussion:

      - -

      Addresses UK 334

      - -

      -Behaviour of get() is undefined if calling get() while -not is_ready(). The intent is that get() is a blocking -call, and will wait for the future to become ready. -

      - -

      [ -Summit: -]

      - - -
      -

      -Agree, move to Review. -

      -
      - -

      [ -2009-04-03 Thomas J. Gritzan adds: -]

      - - -
      -

      -This issue also applies to shared_future::get(). -

      - -

      -Suggested wording: -

      - -

      -Add a paragraph to [futures.shared_future]: -

      - -
      void shared_future<void>::get() const;
-
      -
      -Effects: If is_ready() would return false, block on the asynchronous -result associated with *this. -
      -
      -
      - -

      [ -Batavia (2009-05): -]

      - -
      -It is not clear to us that this is an issue, -because the proposed resolution's Effects clause seems to duplicate -information already present in the Synchronization clause. -Keep in Review status. -
      - - -

      Proposed resolution:

      -

      -Add a paragraph to 30.6.5 [futures.unique_future]: -

      - -
      R&& unique_future::get(); 
-R& unique_future<R&>::get(); 
-void unique_future<void>::get();
-
      -
      -

      Note:...

      -

      -Effects: If is_ready() would return false, -block on the asynchronous result associated with *this. -

      -

      -Synchronization: if *this is associated with a -promise object, the completion of set_value() or -set_exception() to that promise happens before (1.10) -get() returns. -

      -
      -
      - - - - - -
      -

      1048. Response to UK 335

      -

      Section: 30.6.5 [futures.unique_future] Status: Open - Submitter: Alisdair Meredith Opened: 2009-03-12 Last modified: 2009-03-13

      -

      View other active issues in [futures.unique_future].

      -

      View all other issues in [futures.unique_future].

      -

      View all issues with Open status.

      -

      Discussion:

      - -

      Addresses UK 335

      - -

      -std::unique_future is MoveConstructible, so you can transfer the -association with an asynchronous result from one instance to another. -However, there is no way to determine whether or not an instance has -been moved from, and therefore whether or not it is safe to wait for it. -

      - -
      std::promise<int> p;
-std::unique_future<int> uf(p.get_future());
-std::unique_future<int> uf2(std::move(uf));
-uf.wait(); // oops, uf has no result to wait for. 
-
      - -

      -Suggest we add a waitable() function to unique_future -(and shared_future) akin to std::thread::joinable(), -which returns true if there is an associated result to wait for -(whether or not it is ready). -

      - -

      -Then we can say: -

      - -
      if(uf.waitable()) uf.wait();
-
      - -

      [ -Summit: -]

      - - -
      -

      -Create an issue. Requires input from Howard. Probably NAD. -

      -
      - -

      [ -Post Summit, Howard thows in his two cents: -]

      - - -
      -

      -Here is a copy/paste of my last prototype of unique_future which was -several years ago. At that time I was calling unique_future future: -

      - -
      template <class R>
-class future
-{
-public:
-    typedef R result_type;
-private:
-    future(const future&);// = delete;
-    future& operator=(const future&);// = delete;
-
-    template <class R1, class F1> friend class prommise;
-public:
-    future();
-    ~future();
-
-    future(future&& f);
-    future& operator=(future&& f);
-
-    void swap(future&& f);
-
-    bool joinable() const;
-    bool is_normal() const;
-    bool is_exceptional() const;
-    bool is_ready() const;
-
-    R get();
-
-    void join();
-    template <class ElapsedTime>
-        bool timed_join(const ElapsedTime&);
-};
-
      - -

      -shared_future had a similar interface. I intentionally reused -the thread interface where possible to lessen the learning -curve std::lib clients will be faced with. -

      -
      - - - -

      Proposed resolution:

      - - - - - -
      -

      1049. Response to UK 339

      -

      Section: 30.6.4 [futures.promise] Status: Review - Submitter: Alisdair Meredith Opened: 2009-03-12 Last modified: 2009-05-23

      -

      View other active issues in [futures.promise].

      -

      View all other issues in [futures.promise].

      -

      View all issues with Review status.

      -

      Discussion:

      - -

      Addresses UK 339

      - -

      -Move assignment is goiing in the wrong direction, assigning from -*this to the passed rvalue, and then returning a reference to -an unusable *this. -

      - -

      [ -Summit: -]

      - - -
      -

      -Agree, move to Review. -

      -
      - -

      [ -Batavia (2009-05): -]

      - -
      -We recommend deferring this issue until after Detlef's paper (on futures) -has been issued. -
      - - -

      Proposed resolution:

      -

      -Strike 30.6.4 [futures.promise] p6 and change p7: -

      - -
      promise& operator=(promise&& rhs);
-
      -
      -

      --6- Effects: move assigns its associated state to rhs. -

      -

      --7- Postcondition: *this has no associated -state. associated state of *this is the same as the -associated state of rhs before the call. rhs has no -associated state. -

      -
      -
      - - - - - - -
      -

      1050. Response to UK 340

      -

      Section: 30.6.4 [futures.promise] Status: Review - Submitter: Alisdair Meredith Opened: 2009-03-12 Last modified: 2009-05-23

      -

      View other active issues in [futures.promise].

      -

      View all other issues in [futures.promise].

      -

      View all issues with Review status.

      -

      Discussion:

      - -

      Addresses UK 340

      - -

      -There is an implied postcondition for get_future() that the state of the -promise is transferred into the future leaving the promise with no -associated state. It should be spelled out. -

      - -

      [ -Summit: -]

      - - -
      -

      -Agree, move to Review. -

      -
      - -

      [ -2009-04-03 Thomas J. Gritzan adds: -]

      - - -
      -

      -promise::get_future() must not invalidate the state of the promise object. -

      -

      -A promise is used like this: -

      -
      promise<int> p; 
-unique_future<int> f = p.get_future(); 
-// post 'p' to a thread that calculates a value 
-// use 'f' to retrieve the value. 
-
      -

      -So get_future() must return an object that shares the same associated -state with *this. -

      -

      -But still, this function should throw an future_already_retrieved error -when it is called twice. -

      -

      -packaged_task::get_future() throws std::bad_function_call if its future -was already retrieved. It should throw -future_error(future_already_retrieved), too. -

      -

      -Suggested resolution: -

      -

      -Replace p12/p13 30.6.4 [futures.promise]: -

      -
      -

      --12- Throws: future_error if *this has no associated state -the future has already been retrieved. -

      -

      --13- Error conditions: future_already_retrieved if *this -has no associated state -the future associated with -the associated state has already been retrieved. -

      -

      -Postcondition: The returned object and *this share the associated state. -

      -
      -

      -Replace p14 30.6.7 [futures.task]: -

      -
      -

      --14- Throws: std::bad_function_call future_error if the future associated with -the task has already been retrieved. -

      - -

      -Error conditions: future_already_retrieved if the future associated with -the task has already been retrieved. -

      -

      -Postcondition: The returned object and *this share the associated task. -

      -
      -
      - -

      [ -Batavia (2009-05): -]

      - -
      -Keep in Review status -pending Detlef's forthcoming paper on futures. -
      - - -

      Proposed resolution:

      -

      -Add after p13 30.6.4 [futures.promise]: -

      - -
      unique_future<R> get_future();
-
      -
      -

      --13- ... -

      -

      -Postcondition: *this has no associated state. -

      -
      -
      - - - - - - -
      -

      1051. Response to UK 279

      -

      Section: 24.5.1.2.12 [reverse.iter.opindex], 24.5.2.2.12 [move.iter.op.index] Status: Open - Submitter: Alisdair Meredith Opened: 2009-03-12 Last modified: 2009-07-27

      -

      View all issues with Open status.

      -

      Discussion:

      - -

      Addresses UK 279

      - -

      -The reason the return type became unspecified is LWG issue 386. This -reasoning no longer applies as there are at least two ways to get the right -return type with the new language facilities added since the previous -standard. -

      - -

      -Proposal: Specify the return type using either decltype or the Iter concept_map. -

      - -

      [ -Summit: -]

      - - -
      -

      -Under discussion. This is a general question about all iterator -adapters. -

      -
      - -

      [ -Howard adds post Summit: -]

      - - -
      -I am requesting test cases to demonstrate a position. -
      - -

      [ -2009-07-24 Daniel adds: -]

      - - -
      -

      -I recommend NAD. Without concepts we can no longer -restrict this member in a trivial way. Using decltype the -declaration would be along the lines of -

      -
      static const Iter& __base(); // not defined
-auto operator[](difference_type n) const -> decltype(__base()[-n-1]);
-
      - -

      -but once reverse_iterator is instantiated for some given type -Iter which cannot form a well-formed expression __base()[-n-1] -this would cause an ill-formed function declaration, diagnostic -required, and no silent SFINAE elimination. -

      - +Looked at this and still intend to close as NAD in March +2010 unless there is proposed wording that we like.
      @@ -24287,9 +15778,9 @@ required, and no silent SFINAE elimination.

      1052. Response to UK 281

      -

      Section: 24.5.1.2.5 [reverse.iter.opref] Status: Open - Submitter: Alisdair Meredith Opened: 2009-03-12 Last modified: 2009-08-01

      -

      View all issues with Open status.

      +

      Section: 24.5.1.3.5 [reverse.iter.opref] Status: Ready + Submitter: Alisdair Meredith Opened: 2009-03-12 Last modified: 2009-10-22

      +

      View all issues with Ready status.

      Discussion:

      Addresses UK 281

      @@ -24333,13 +15824,20 @@ Howard to deconceptize. Move to Review after that happens.
      +

      [ +2009-10 Santa Cruz: +]

      -

      Proposed resolution:

      +

      -Change synopsis in 24.5.1.1 [reverse.iterator]: +We can't think of any reason we can't just define reverse +iterator's pointer types to be the same as the underlying iterator's +pointer type, and get it by calling the right arrow directly. +

      +

      +Here is the proposed wording that was replaced:

      - 
      template <class Iterator> 
 class reverse_iterator { 
   ...
@@ -24347,7 +15845,7 @@ class reverse_iterator {

      -Change 24.5.1.2.5 [reverse.iter.opref]: +Change 24.5.1.3.5 [reverse.iter.opref]: 

      pointer operator->() const;
@@ -24361,324 +15859,41 @@ Change 24.5.1.2.5 [reverse.iter.opref]:
      - - - - - - -
      -

      1053. Response to UK 295

      -

      Section: 25 [algorithms] Status: Open - Submitter: Alisdair Meredith Opened: 2009-03-12 Last modified: 2009-03-13

      -

      View other active issues in [algorithms].

      -

      View all other issues in [algorithms].

      -

      View all issues with Open status.

      -

      Discussion:

      - -

      Addresses UK 295

      - -

      -There is a level of redundancy in the library specification for many -algorithms that can be eliminated with the combination of concepts and -default parameters for function templates. Eliminating redundancy simplified -specification and reduces the risk of introducing accidental -inconsistencies. -

      -

      -Proposed resolution: Adopt -N2743. -

      - -

      [ -Summit: -]

      - - -
      -

      -NAD, this change would break code that takes the address of an -algorithm. -

      -
      - -

      [ -Post Summit Alisdair adds: -]

      - - -
      -

      -Request 'Open'. The issues in the paper go beyond just reducing -the number of signatures, but cover unifying the idea of the ordering -operation used by algorithms, containers and other library components. At -least, it takes a first pass at the problem. -

      - -

      -For me (personally) that was the more important part of the paper, and not -clearly addressed by the Summit resolution. -

      Proposed resolution:

      - - - - - -
      -

      1054. forward broken

      -

      Section: 20.3.2 [forward] Status: Open - Submitter: Howard Hinnant Opened: 2009-03-13 Last modified: 2009-08-02

      -

      View other active issues in [forward].

      -

      View all other issues in [forward].

      -

      View all issues with Open status.

      -

      Discussion:

      -

      -This is a placeholder issue to track the fact that we (well I) put the standard -into an inconsistent state by requesting that we accept -N2844 -except for the proposed changes to [forward]. +Change 24.5.1.3.5 [reverse.iter.opref]:

      -

      -There will exist in the post meeting mailing -N2835 -which in its current state reflects the state of affairs prior to the Summit -meeting. I hope to update it in time for the post Summit mailing, but as I write -this issue I have not done so yet. -

      - -

      [ -Batavia (2009-05): -]

      - +
      pointer operator->() const;
+
      -Move to Open, awaiting the promised paper. -
      - -

      [ -2009-08-02 Howard adds: -]

      - - -
      -

      -My current preferred solution is: -

      - -
      template <class T>
-struct __base_type
-{
-   typedef typename remove_cv<typename remove_reference<T>::type>::type type;
-};
-
-template <class T, class U,
-   class = typename enable_if<
-       !is_lvalue_reference<T>::value ||
-        is_lvalue_reference<T>::value &&
-        is_lvalue_reference<U>::value>::type,
-   class = typename enable_if<
-        is_same<typename __base_type<T>::type,
-                typename __base_type<U>::type>::value>::type>
-inline
-T&&
-forward(U&& t)
-{
-   return static_cast<T&&>(t);
-}
+Returns:
+
      &(operator*());
+deref_tmp = current;
+--deref_tmp;
+return deref_tmp::operator->();
 
      
-
-
      
-This has been tested by Bill, Jason and myself.
-
      
-
-
      
-It allows the following lvalue/rvalue casts:
-
      
-
-
        
-
      1. 
-Cast an lvalue t to an lvalue T (identity).
-
        2. 
-
      2. 
-Cast an lvalue t to an rvalue T.
-
        3. 
-
      3. 
-Cast an rvalue t to an rvalue T (identity).
-
        4. 
-
      
-
-
      
-It disallows:
-
      
-
-
        
-
      1. 
-Cast an rvalue t to an lvalue T.
-
        2. 
-
      2. 
-Cast one type t to another type T (such as int to double).
-
        3. 
-
      
-
-
      
-"a." is disallowed as it can easily lead to dangling references.
-"b." is disallowed as this function is meant to only change the lvalue/rvalue
-characteristic of an expression.
-
      
-
-
      
-Jason has expressed concern that "b." is not dangerous and is useful in contexts
-where you want to "forward" a derived type as a base type.  I find this use case
-neither dangerous, nor compelling.  I.e. I could live with or without the "b."
-constraint.  Without it, forward would look like:
-
      
-
-
      template <class T, class U,
-   class = typename enable_if<
-       !is_lvalue_reference<T>::value ||
-        is_lvalue_reference<T>::value &&
-        is_lvalue_reference<U>::value>::type>
-inline
-T&&
-forward(U&& t)
-{
-   return static_cast<T&&>(t);
-}
-
      
-
-
      
-Or possibly:
-
      
-
-
      template <class T, class U,
-   class = typename enable_if<
-       !is_lvalue_reference<T>::value ||
-        is_lvalue_reference<T>::value &&
-        is_lvalue_reference<U>::value>::type,
-   class = typename enable_if<
-        is_base_of<typename __base_type<U>::type,
-                   typename __base_type<T>::type>::value>::type>
-inline
-T&&
-forward(U&& t)
-{
-   return static_cast<T&&>(t);
-}
-
      
-
-
-
      
-The "promised paper" is not in the post-Frankfurt mailing only because I'm waiting
-for the non-concepts draft.  But I'm hoping that by adding this information here
-I can keep people up to date.
-
      
+
      -

      Proposed resolution:

      -
      -

      1055. Response to UK 98

      -

      Section: 20.6.7 [meta.trans.other] Status: Open - Submitter: Alisdair Meredith Opened: 2009-03-12 Last modified: 2009-05-23

      -

      View other active issues in [meta.trans.other].

      -

      View all other issues in [meta.trans.other].

      -

      View all issues with Open status.

      -

      Discussion:

      - -

      Addresses UK 98

      - -

      -It would be useful to be able to determine the underlying -type of an arbitrary enumeration type. This would allow -safe casting to an integral type (especially needed for -scoped enums, which do not promote), and would allow -use of numeric_limits. In general it makes generic -programming with enumerations easier. -

      - -

      [ -Batavia (2009-05): -]

      - -
      -Pete observes (and Tom concurs) -that the proposed resolution seems to require compiler support -for its implementation, -as it seems necessary to look at the range of values -of the enumerated type. -To a first approximation, -a library solution could give an answer based on the size of the type. -If the user has specialized numeric_limits for the enumerated type, -then the library might be able to do better, -but there is no such requirement. -Keep status as Open -and solicit input from CWG. -
      - -

      [ -2009-05-23 Alisdair adds: -]

      - - -
      -Just to confirm that the BSI originator of this comment assumed it did -indeed imply a compiler intrinsic. Rather than request a Core extension, it -seemed in keeping with that the type traits interface provides a library API -to unspecified compiler features - where we require several other traits -(e.g. has_trivial_*) to get the 'right' answer now, unlike in TR1. -
      - - -

      Proposed resolution:

      -

      -Add a new row to the table in 20.6.7 [meta.trans.other]: -

      - -
      - - - - - - - - - - - - -
      Table 41 -- Other transformations
      TemplateConditionComments
      -template< class T > struct enum_base; - -T shall be an enumeration type (7.2 [dcl.enum]) - -The member typedef type shall name the underlying type -of the enum T. -
      -
      - - - -

      1056. Must all Engines and Distributions be Streamable?

      -

      Section: 26.5 [rand] Status: Open - Submitter: Alisdair Meredith Opened: 2009-03-12 Last modified: 2009-05-31

      +

      Section: 26.5 [rand] Status: Tentatively NAD + Submitter: Alisdair Meredith Opened: 2009-03-12 Last modified: 2009-11-03

      View all other issues in [rand].

      -

      View all issues with Open status.

      +

      View all issues with Tentatively NAD status.

      Discussion:

      @@ -24742,91 +15957,48 @@ today.

      - -

      Proposed resolution:

      - - - - - -
      -

      1062. Missing insert_iterator for stacks/queues

      -

      Section: 24.7 [insert.iterators] Status: Tentatively NAD Future - Submitter: Alisdair Meredith Opened: 2009-03-13 Last modified: 2009-07-29

      -

      View other active issues in [insert.iterators].

      -

      View all other issues in [insert.iterators].

      -

      View all issues with Tentatively NAD Future status.

      -

      Discussion:

      - -

      -It is odd that we have an iterator to insert into a vector, but not an -iterator to insert into a vector that is adapted as a stack. The standard -container adapters all have a common interface to push and pop so it should -be simple to create an iterator adapter to complete the library support. -

      - -

      -We should provide an AdaptedContainer concept supporting push and pop -operations. Create a new insert iterator and factory function that inserts -values into the container by calling push. -

      -

      [ -Batavia (2009-05): +2009-11-03 Alisdair adds: ]

      +

      -Walter recommends NAD Future. +I can't find the record in the wiki minutes, but it was agreed at both +Frankfurt and Santa Cruz that this issue is NAD.

      -Move to Open, and recommend deferring the issue until after the next -Committee Draft is issued. +The agreement in SC was that I would provide you with the rationale (see +below) to include when moving to NAD.

      [ -2009-07-29 Howard moves to Tentatively NAD Future. +2009-11-03 Howard adds: ]

      -A poll on the LWG reflector voted unanimously to move this issue to Tentatively NAD Future. +Moved to Tentatively NAD after 5 positive votes on c++std-lib.

      Proposed resolution:

      - - - -
      -

      1064. Response to UK 152

      -

      Section: 17.3.15 [defns.obj.state] Status: Open - Submitter: Howard Hinnant Opened: 2009-03-15 Last modified: 2009-03-15

      -

      View all issues with Open status.

      -

      Discussion:

      - -

      Addresses UK 152

      - +

      Rationale:

      -Object state is using a definition of object (instance of a class) from -outside the standard, rather than the 'region of storage' definiton in -1.8 [intro.object]p1 +The issue suggests a more refined concept should be used if we want to +require streaming, to separate concerns from the basic +RandomNumberEngine behaviour. In Frankfurt it was observed +that RandomNumberEngine is that more refined concept, +and the basic concept used in the framework is +UniformRandomNumberGenerator, which it refines.

      -

      [ -Summit: -]

      - -
      -We think we're removing this; See X [func.referenceclosure.cons]. -
      - - -

      Proposed resolution:

      +We concur, and expect this to have no repurcussions re-writing this +clause now concepts are removed.

      @@ -24836,7 +16008,7 @@ We think we're removing this; See X [func.referenceclosure.cons].

      1068. class random_device should be movable

      Section: 26.5.6 [rand.device] Status: Open - Submitter: Alisdair Meredith Opened: 2009-03-18 Last modified: 2009-05-23

      + Submitter: Alisdair Meredith Opened: 2009-03-18 Last modified: 2009-10-26

      View all other issues in [rand.device].

      View all issues with Open status.

      Discussion:

      @@ -24854,6 +16026,16 @@ Move to Open, and recommend this issue be deferred until after the next Committee Draft is issued. +

      [ +2009-10 post-Santa Cruz: +]

      + + +
      +Leave open. Walter to provide drafting as part of his planned paper. +
      + +

      Proposed resolution:

      @@ -24864,7 +16046,7 @@ Committee Draft is issued.

      1069. class seed_seq should support efficient move operations

      Section: 26.5.7.1 [rand.util.seedseq] Status: Open - Submitter: Alisdair Meredith Opened: 2009-03-18 Last modified: 2009-05-23

      + Submitter: Alisdair Meredith Opened: 2009-03-18 Last modified: 2009-10-26

      View all other issues in [rand.util.seedseq].

      View all issues with Open status.

      Discussion:

      @@ -24882,6 +16064,16 @@ Move to Open, and recommend this issue be deferred until after the next Committee Draft is issued. +

      [ +2009-10 post-Santa Cruz: +]

      + + +
      +Leave open. Walter to provide drafting as part of his planned paper. +
      + +

      Proposed resolution:

      @@ -24891,13 +16083,13 @@ Committee Draft is issued.

      1071. is_bind_expression should derive from integral_constant<bool>

      -

      Section: 20.7.12.1.1 [func.bind.isbind] Status: Open - Submitter: Alisdair Meredith Opened: 2009-03-19 Last modified: 2009-05-31

      -

      View all issues with Open status.

      +

      Section: 20.7.11.1.1 [func.bind.isbind] Status: Tentatively Ready + Submitter: Alisdair Meredith Opened: 2009-03-19 Last modified: 2009-10-26

      +

      View all issues with Tentatively Ready status.

      Discussion:

      -Class template is_bind_expression 20.7.12.1.1 [func.bind.isbind]: +Class template is_bind_expression 20.7.11.1.1 [func.bind.isbind]: 

      namespace std {
@@ -24964,13 +16156,23 @@ alone.
      +

      [ +2009-10 post-Santa Cruz: +]

      + + +
      +Move to Tentatively Ready. We are comfortable with requiring user specializations +to derive from integral_constant. +
      +

      Proposed resolution:

      1. -In 20.7.12.1.1 [func.bind.isbind] change as indicated: +In 20.7.11.1.1 [func.bind.isbind] change as indicated: 

        namespace std {
  template<class T> struct is_bind_expression : integral_constant<bool, see below> { };{
@@ -24981,7 +16183,7 @@ In 20.7.12.1.1 [func.bind.isbind] change as indicated:

      2. -In 20.7.12.1.1 [func.bind.isbind]/2 change as indicated: +In 20.7.11.1.1 [func.bind.isbind]/2 change as indicated: 

        static const bool value;
        @@ -24997,7 +16199,7 @@ publicly derived from

      3. -In 20.7.12.1.2 [func.bind.isplace] change as indicated: +In 20.7.11.1.2 [func.bind.isplace] change as indicated: 

        namespace std {
  template<class T> struct is_placeholder : integral_constant<int, see below> { };{
@@ -25008,7 +16210,7 @@ In 20.7.12.1.2 [func.bind.isplace] change as indicated:

      4. -In 20.7.12.1.2 [func.bind.isplace]/2 change as indicated: +In 20.7.11.1.2 [func.bind.isplace]/2 change as indicated: 

        static const int value;
        @@ -25028,250 +16230,10 @@ be publicly derived -
        -

        1075. Response to US 65, US 74.1

        -

        Section: 20 [utilities], 23 [containers] Status: Open - Submitter: Alan Talbot Opened: 2009-03-20 Last modified: 2009-06-10

        -

        View all other issues in [utilities].

        -

        View all issues with Open status.

        -

        Discussion:

        -

        Addresses US 65 and US 74.1

        - -

        US 65:

        - -
        -Scoped allocators and allocator propagation traits add a small amount of -utility at the cost of a great deal of machinery. The machinery is user -visible, and it extends to library components that don't have any -obvious connection to allocators, including basic concepts and simple -components like pair and tuple. - -

        Suggested resolution:

        - -

        -Sketch of proposed resolution: Eliminate scoped allocators, replace -allocator propagation traits with a simple uniform rule (e.g. always -propagate on copy and move), remove all mention of allocators from -components that don't explicitly allocate memory (e.g. pair), and adjust -container interfaces to reflect this simplification. -

        -

        -Components that I propose eliminating include HasAllocatorType, -is_scoped_allocator, allocator_propagation_map, scoped_allocator_adaptor, -and ConstructibleAsElement. -

        -
        - -

        US 74.1:

        - -
        -

        -Scoped allocators represent a poor trade-off for standardization, since -(1) scoped-allocator--aware containers can be implemented outside the -C++ standard library but used with its algorithms, (2) scoped -allocators only benefit a tiny proportion of the C++ community -(since few C++ programmers even use today's allocators), and (3) all C++ -users, especially the vast majority of the C++ community that won't ever -use scoped allocators are forced to cope with the interface complexity -introduced by scoped allocators. -

        -

        -In essence, the larger community will suffer to support a very small -subset of the community who can already implement their own -data structures outside of the standard library. Therefore, scoped -allocators should be removed from the working paper. -

        -

        -Some evidence of the complexity introduced by scoped allocators: -

        -
        -

        -20.3.3 [pairs], 20.5 [tuple]: Large increase in the -number of pair and tuple constructors. -

        -

        -23 [containers]: Confusing "AllocatableElement" requirements throughout. -

        -
        -

        Suggested resolution:

        - -

        -Remove support for scoped allocators from the working paper. This -includes at least the following changes: -

        - -
        -

        -Remove 20.8.3 [allocator.element.concepts] -

        -

        -Remove 20.8.5 [allocator.adaptor] -

        -

        -Remove [construct.element] -

        -

        -In Clause 23 [containers]: replace requirements naming the -AllocatableElement concept with requirements naming CopyConstructible, -MoveConstructible, DefaultConstructible, or Constructible, as -appropriate. -

        -
        - -
        - -

        [ -Post Summit Alan moved from NAD to Open. -]

        - - -

        [ -2009-05-15 Ganesh adds: -]

        - - -
        -

        -The requirement AllocatableElement should not be replaced with -Constructible on the emplace_xxx() functions as suggested. In the -one-parameter case the Constructible requirement is not satisfied when -the constructor is explicit (as per 14.10.2.1 [concept.map.fct], twelfth -bullet) but we do want to allow explicit constructors in emplace, as the -following example shows: -

        - -
        vector<shared_ptr<int>> v;
-v.emplace_back(new int); // should be allowed
-
        - -

        -If the issue is accepted and scoped allocators are removed, I suggest to -add a new pair of concepts to 20.2.7 [concept.construct], namely: -

        - -
        auto concept HasExplicitConstructor<typename T, typename... Args> {
- explicit T::T(Args...);
-}
-
-auto concept ExplicitConstructible<typename T, typename... Args>
- : HasExplicitConstructor<T, Args...>, NothrowDestructible<T>
-{ }
-
        - -

        -We should then use ExplicitConstructible as the requirement for all -emplace_xxx() member functions. -

        -

        -For coherence and consistency with the similar concepts -Convertible/ExplicitlyConvertible, we might also consider changing -Constructible to: -

        - -
        auto concept Constructible<typename T, typename... Args>
- : HasConstructor<T, Args...>, ExplicitConstructible<T, Args...>
-{ }
-
        - -

        -Moreover, all emplace-related concepts in 23.2.6 [container.concepts] -should also use ExplicitConstructible instead of Constructible in the -definitions of their axioms. In fact the concepts in 23.2.6 [container.concepts] should be -corrected even if the issue is not accepted. -

        -

        -On the other hand, if the issue is not accepted, the scoped allocator -adaptors should be fixed because the following code: -

        - -
        template <typename T> using scoped_allocator = scoped_allocator_adaptor<allocator<T>>;
-
-vector<shared_ptr<int>, scoped_allocator<shared_ptr<int>>> v;
-v.emplace_back(new int); // ops! doesn't compile
-
        - -

        -doesn't compile, as the member function construct() of the scoped -allocator requires non-explicit constructors through concept -ConstructibleWithAllocator. Fixing that is not difficult but probably -more work than it's worth and is therefore, IMHO, one more reason in -support of the complete removal of scoped allocators. -

        -
        - -

        [ -2009-06-09 Alan adds: -]

        - - -
        -

        -I reopened this issue because I did not think that these National Body -comments were adequately addressed by marking them NAD. My understanding -is that something can be marked NAD if it is clearly a misunderstanding -or trivial, but a substantive issue that has any technical merit -requires a disposition that addresses the concerns. -

        -

        -The notes in the NB comment list (US 65 & US 74.1) say that: -

        -
          -
        1. -this issue has not introduced any new arguments not previously discussed, -
          2. -
        2. -the vote (4-9-3) was not a consensus for removing scoped allocators, -
          3. -
        3. -the issue is resolved by -N2840. -
          4. -
        -

        -My opinion is: -

        -
          -
        1. -there are new arguments in both comments regarding concepts (which were -not present in the library when the scoped allocator proposal was voted -in), -
          2. -
        2. -the vote was clearly not a consensus for removal, but just saying there -was a vote does not provide a rationale, -
          3. -
        3. -I do not believe that N2840 addresses these comments (although it does -many other things and was voted in with strong approval). -
          4. -
        - -

        -My motivation to open the issue was to ensure that the NB comments were -adequately addressed in a way that would not risk a "no" vote on our -FCD. If there are responses to the technical concerns raised, then -perhaps they should be recorded. If the members of the NB who authored -the comments are satisfied with N2840 and the other disposition remarks -in the comment list, then I am sure they will say so. In either case, -this issue can be closed very quickly in Frankfurt, and hopefully will -have helped make us more confident of approval with little effort. If in -fact there is controversy, my thought is that it is better to know now -rather than later so there is more time to deal with it. -

        -
        - - - -

        Proposed resolution:

        - - - - -

        1076. unary/binary_negate need constraining and move support

        -

        Section: 20.7.11 [negators] Status: Open - Submitter: Alisdair Meredith Opened: 2009-03-20 Last modified: 2009-05-23

        +

        Section: 20.7.10 [negators] Status: Open + Submitter: Alisdair Meredith Opened: 2009-03-20 Last modified: 2009-10-26

        View all issues with Open status.

        Discussion:

        @@ -25431,6 +16393,17 @@ Move to Open.

        +

        [ +2009-10 post-Santa Cruz: +]

        + + +
        +Leave open pending the potential move constructor paper. Note that +we consider the "constraining" part NAD Concepts. +
        + +

        Proposed resolution:

        @@ -25479,7 +16452,7 @@ argument and result types:

        -Negators 20.7.11 [negators]: +Negators 20.7.10 [negators]:

        @@ -25557,11 +16530,10 @@ respectively, and return their complements (5.3.1).

        1079. UK-265: RandomAccessIterator's operator- has nonsensical effects clause

        -

        Section: 24.2.6 [random.access.iterators] Status: Open - Submitter: Doug Gregor Opened: 2009-03-20 Last modified: 2009-03-22

        -

        View other active issues in [random.access.iterators].

        +

        Section: 24.2.5 [random.access.iterators] Status: Ready + Submitter: Doug Gregor Opened: 2009-03-20 Last modified: 2009-10-23

        View all other issues in [random.access.iterators].

        -

        View all issues with Open status.

        +

        View all issues with Ready status.

        Discussion:

        Addresses UK 265

        @@ -25572,11 +16544,41 @@ equivalence, and certainly an effects clause cannot change the state of two arguments passed by const reference

        +

        [ +2009-09-18 Alisdair adds: +]

        + + +
        +

        +For random access iterators, the definitions of (b-a) and +(a<b) are circular: +

        + +

        +From table Table 104 -- Random access iterator requirements: +

        + +
        b - a :==>  (a < b) ? distance(a,b) : -distance(b,a)
+
+a < b :==>  b - a > 0
+
        +
        + +

        [ +2009-10 Santa Cruz: +]

        + + +
        +Moved to Ready. +
        +

        Proposed resolution:

        -

        Modify 24.2.6 [random.access.iterators]p7-9 as follows:

        +

        Modify 24.2.5 [random.access.iterators]p7-9 as follows:

        difference_type operator-(const X& a, const X& b);
        @@ -25593,98 +16595,10 @@ two arguments passed by const reference -
        -

        1088. Response to UK 342

        -

        Section: 30.6.4 [futures.promise] Status: Open - Submitter: Howard Hinnant Opened: 2009-03-22 Last modified: 2009-03-22

        -

        View other active issues in [futures.promise].

        -

        View all other issues in [futures.promise].

        -

        View all issues with Open status.

        -

        Discussion:

        -

        Addresses UK 342

        - -

        -std::promise is missing a non-member overload of swap. This is -inconsistent with other types that provide a swap member function. -

        - -

        -Add a non-member overload void swap(promise&& x,promise&& y){ x.swap(y); } -

        - -

        [ -Summit: -]

        - -
        -Create an issue. Move to review, attention: Howard. Detlef will also -look into it. -
        - -

        [ -Post Summit Daniel provided wording. -]

        - - - -

        Proposed resolution:

        -
          -
        1. -

          -In 30.6.4 [futures.promise], before p.1, immediately after class template -promise add: -

          -
          
-template <class R>
-void swap(promise<R>& x, promise<R>& y);
-
-
          -
          2. -
        2. -

          -Change 30.6.4 [futures.promise]/10 as indicated (to fix a circular definition): -

          -
          -

          --10- Effects: swap(*this, other)Swaps the associated state -of *this and other -

          -

          -Throws: Nothing. -

          -
          -
          3. -
        3. -

          -After the last paragraph in 30.6.4 [futures.promise] add the following -prototype description: -

          -
          
-template <class R>
-void swap(promise<R>& x, promise<R>& y);
-
          -
          -

          -Effects: x.swap(y) -

          -

          -Throws: Nothing. -

          -
          -
          -
          4. - -
        - - - - - -

        1089. Response to JP 76

        Section: 30 [thread] Status: Open - Submitter: Howard Hinnant Opened: 2009-03-22 Last modified: 2009-08-02

        + Submitter: Howard Hinnant Opened: 2009-03-22 Last modified: 2009-10-23

        View all other issues in [thread].

        View all issues with Open status.

        Discussion:

        @@ -25881,8 +16795,15 @@ Add a paragraph under 30.5.2 [thread.condition.condvarany] p19, p21 and p25:
        +

        [ +2009-10 Santa Cruz: +]

        +
        +Defer pending further developments with exception restriction annotations. +
        +

        Proposed resolution:

        @@ -25910,7 +16831,7 @@ that would cause the exception

        A "Throws: Nothing." element indicates that the function shall -return ordinarily, and not via an exception. This element also +return ordinarily, and not exit via an exception. This element also indicates that the function shall return. [Note: This differs from an empty throw specification which may cause a function to call unexpected and subsequently terminate. — @@ -26009,12 +16930,12 @@ Add a paragraph under 30.5.2 [thread.condition.condvarany] p6 and p7:

        1090. Missing description of packaged_task member swap, missing non-member swap

        -

        Section: 30.6.7 [futures.task] Status: Open - Submitter: Daniel Krügler Opened: 2009-03-22 Last modified: 2009-05-24

        -

        View all issues with Open status.

        +

        Section: 30.6.10 [futures.task] Status: Tentatively Ready + Submitter: Daniel Krügler Opened: 2009-03-22 Last modified: 2009-10-26

        +

        View all issues with Tentatively Ready status.

        Discussion:

        -Class template packaged_task in 30.6.7 [futures.task] shows a member swap +Class template packaged_task in 30.6.10 [futures.task] shows a member swap declaration, but misses to document it's effects (No prototype provided). Further on this class misses to provide a non-member @@ -26044,12 +16965,23 @@ Move to Open. ]

        +

        [ +2009-10 post-Santa Cruz: +]

        + + +
        +Move to Tentatively Ready, removing bullet 3 from the proposed +resolution but keeping the other two bullets. +
        + +

        Proposed resolution:

        1. -In 30.6.7 [futures.task], immediately after the definition of class +In 30.6.10 [futures.task], immediately after the definition of class template packaged_task add: 

          
@@ -26060,27 +16992,11 @@ void swap(packaged_task<R(ArgTypes...)>&, packaged_task<R(ArgTypes.
        -
          +
            +

          1. -In 30.6.7 [futures.task], immediately after operator= prototype -description (After p. 8) add: -

            -
            void swap(packaged_task& other);
-
            -
            -

            -Effects: Swaps the associated state of *this and other. -

            -

            -Throws: Nothing. -

            -
            -
            -
            2. -
          2. -

            -At the end of 30.6.7 [futures.task] (after p. 20), add add the following +At the end of 30.6.10 [futures.task] (after p. 20), add add the following prototype description:

            @@ -26104,60 +17020,10 @@ void swap(packaged_task<R(ArgTypes...)>& x, packaged_task<R(ArgType -
            -

            1091. Multimap description confusing

            -

            Section: 23.4.2.2 [multimap.modifiers] Status: Review - Submitter: LWG Opened: 2009-03-22 Last modified: 2009-07-04

            -

            View all issues with Review status.

            -

            Discussion:

            - -

            Addresses UK 246

            -

            -The content of this sub-clause is purely trying to describe in words the -effect of the requires clauses on these operations, now that we have -Concepts. As such, the description is more confusing than the signature -itself. The semantic for these functions is adequately covered in the -requirements tables in 23.2.4 [associative.reqmts]. -

            - -

            [ -Beman adds: -]

            - - -
            -Pete is clearly right that -this one is technical rather than editorial. -
            - -

            [ -Batavia (2009-05): -]

            - -
            -

            -We agree with the proposed resolution. -

            -

            -Move to Review. -

            -
            - - -

            Proposed resolution:

            -

            -Strike 23.4.2.2 [multimap.modifiers] entirely -(but do NOT strike these signatures from the class template definition!). -

            - - - - -

            1093. Multiple definitions for random_shuffle algorithm

            -

            Section: 25.4.12 [alg.random.shuffle] Status: Open - Submitter: Alisdair Meredith Opened: 2009-03-22 Last modified: 2009-07-28

            +

            Section: 25.3.12 [alg.random.shuffle] Status: Open + Submitter: Alisdair Meredith Opened: 2009-03-22 Last modified: 2009-10-26

            View all other issues in [alg.random.shuffle].

            View all issues with Open status.

            Discussion:

            @@ -26220,9 +17086,9 @@ To realize it's designated task, the algorithm has to invoke the Callable aspect of g and needs to perform some algebra involving it's min()/max() limits to compute another index value that at this point is converted into Iter::difference_type. This is so, -because 24.2.6 [random.access.iterators] uses this type as argument +because 24.2.5 [random.access.iterators] uses this type as argument of it's algebraic operators. Alternatively consider the equivalent -iterator algorithms in 24.4 [iterator.operations] with the same result. +iterator algorithms in 24.4.4 [iterator.operations] with the same result.

            This argument leads us to the conclusion that we also need @@ -26264,10 +17130,20 @@ Revert to Open, with a note there is consensus on direction but the wording needs updating to reflect removal of concepts.

        +

        [ +2009-10 post-Santa Cruz: +]

        + + +
        +Leave Open, Walter to work on it. +
        + +

        Proposed resolution:

        -Change in 25.2 [algorithms.syn] and 25.4.12 [alg.random.shuffle]: +Change in [algorithms.syn] and 25.3.12 [alg.random.shuffle]: 

        concept UniformRandomNumberGenerator<typename Rand> { }
@@ -26284,10 +17160,10 @@ template<RandomAccessIterator Iter, UniformRandomNumberGenerator Rand>
 
 
        
 
        1094. Response to JP 65 and JP 66
        
-
        Section: 27.5.4.3 [iostate.flags] Status: Review
- Submitter: P.J. Plauger Opened: 2009-03-24  Last modified: 2009-05-23
        
+
        Section: 27.5.4.3 [iostate.flags] Status: Ready
+ Submitter: P.J. Plauger Opened: 2009-03-24  Last modified: 2009-10-20
        
 
        View all other issues in [iostate.flags].
        
-
        View all issues with Review status.
        
+
        View all issues with Ready status.
        
 
        Discussion:
        
 
        Addresses JP 65 and JP 66
        
 
@@ -26308,6 +17184,16 @@ We agree with the proposed resolution.
 Move to Review.
        +

        [ +2009 Santa Cruz: +]

        + + +
        +Moved to Ready. +
        + +

        Proposed resolution:

        @@ -26349,9 +17235,9 @@ choice for this type is pointer-to-member. -- end note]

        1095. Shared objects and the library wording unclear

        -

        Section: 17.6.3.10 [res.on.objects] Status: Review - Submitter: Beman Dawes Opened: 2009-03-27 Last modified: 2009-05-23

        -

        View all issues with Review status.

        +

        Section: 17.6.3.10 [res.on.objects] Status: Ready + Submitter: Beman Dawes Opened: 2009-03-27 Last modified: 2009-10-21

        +

        View all issues with Ready status.

        Discussion:

        N2775, @@ -26367,7 +17253,7 @@ without using a locking mechanism may result in a data race. --end note.]

        That resulted in wording which is technically correct but can only be -understood by reading the lengthy and complex 17.6.4.7 [res.on.data.races] +understood by reading the lengthy and complex 17.6.4.8 [res.on.data.races] Data race avoidance. This has the effect of making 17.6.3.10 [res.on.objects] unclear, and has already resulted in a query to the LWG reflector. See c++std-lib-23194. @@ -26391,6 +17277,16 @@ move to Review status.

        +

        [ +2009-10 Santa Cruz: +]

        + + +
        +Note: Change to read: "Modifying...", Delete 'thus', move to Ready +
        + +

        Proposed resolution:

        @@ -26404,7 +17300,7 @@ functions from different threads may introduce a data race. The conditions under which this may occur are specified in 17.6.4.7.

        -[Note: Thus modifying an object of a standard library type shared between +[Note: Modifying an object of a standard library type shared between threads risks undefined behavior unless objects of the type are explicitly specified as being sharable without data races or the user supplies a locking mechanism. --end note] @@ -26417,10 +17313,10 @@ locking mechanism. --end note]

        1097. #define __STDCPP_THREADS

        -

        Section: 18.2 [support.types] Status: Review - Submitter: Jens Maurer Opened: 2009-04-03 Last modified: 2009-05-23

        +

        Section: 18.2 [support.types] Status: Ready + Submitter: Jens Maurer Opened: 2009-04-03 Last modified: 2009-10-21

        View all other issues in [support.types].

        -

        View all issues with Review status.

        +

        View all issues with Ready status.

        Discussion:

        Addresses DE 18

        @@ -26468,6 +17364,16 @@ Move to Review.

        +

        [ +2009-10 Santa Cruz: +]

        + + +
        +Move to Ready. +
        + +

        Proposed resolution:

        @@ -26499,15 +17405,15 @@ If the macro is defined, it shall have the same

        1098. definition of get_pointer_safety()

        -

        Section: 20.8.10.7 [util.dynamic.safety] Status: Open - Submitter: Jens Maurer Opened: 2009-04-03 Last modified: 2009-05-23

        +

        Section: 20.8.15.6 [util.dynamic.safety] Status: Ready + Submitter: Jens Maurer Opened: 2009-04-03 Last modified: 2009-10-23

        View all other issues in [util.dynamic.safety].

        -

        View all issues with Open status.

        +

        View all issues with Ready status.

        Discussion:

        Addresses DE 18

        - In 20.8.10.7 [util.dynamic.safety], get_pointer_safety() purports + In 20.8.15.6 [util.dynamic.safety], get_pointer_safety() purports to define behavior for non-safely derived pointers (3.7.4.3 [basic.stc.dynamic.safety]). However, the cited core-language section in paragraph 4 specifies undefined behavior @@ -26541,11 +17447,20 @@ Move to Open.

        +

        [ +2009-10 Santa Cruz: +]

        + + +
        +The core issue is 853 and is in Ready status. +
        +

        Proposed resolution:

        -In 20.8.10.7 [util.dynamic.safety] p16, replace the description of +In 20.8.15.6 [util.dynamic.safety] p16, replace the description of get_pointer_safety() with:

        @@ -26598,11 +17513,11 @@ Footnote) pointer_safety::preferred might be returned to indicate to th

        1099. Various issues

        -

        Section: 17 [library] Status: Open - Submitter: David Abrahams Opened: 2009-03-21 Last modified: 2009-05-23

        +

        Section: 17 [library] Status: Tentatively NAD + Submitter: David Abrahams Opened: 2009-03-21 Last modified: 2009-10-26

        View other active issues in [library].

        View all other issues in [library].

        -

        View all issues with Open status.

        +

        View all issues with Tentatively NAD status.

        Discussion:

        Notes @@ -26613,6 +17528,26 @@ Notes MoveConstructible V2 (where V1,V2 are defined on 539). Also make_tuple on 550

        + +
        +

        +CD-1 reads: +

        + +
        template <MoveConstructible T1, MoveConstructible T2> 
+pair<V1, V2> make_pair(T1&&, T2&&); 
+
        + +

        +Actually I'm guessing we need something like MoveConstructible<V1,T1>, +i.e. "V1 can be constructed from an rvalue of type T1." +

        + +

        +Ditto for make_tuple +

        +
        +

        [2009-03-21 Sat] p1183 thread ctor, and in general, we need a way to talk about "copiable from generalized rvalue ref argument" for cases @@ -26623,6 +17558,22 @@ where we're going to forward and copy. This issue may well be quite large. Language in para 4 about "if an lvalue" is wrong because types aren't expressions.

        + +
        +

        +Maybe we should define the term "move" so we can just say in the +effects, "f is moved into the newly-created thread" or something, and +agree (and ideally document) that saying "f is moved" implies +

        + +
        F x(move(f))
+
        + +

        +is required to work. That would cover both ctors at once. +

        +
        +

        p1199, call_once has all the same issues.

        @@ -26632,6 +17583,11 @@ where we're going to forward and copy. to be convertible to const value_type*, rather it needs to have a operator-> of its own that can be used for the value type.

        + +
        +This one is serious and unrelated to the move issue. +
        +

        [2009-03-21 Sat] p818 stack has the same problem with default ctor.

        @@ -26666,7 +17622,7 @@ operator-> of its own that can be used for the value type.
        -This could be done as part of 1035, which already handles +This could be done as part of 1035, which already handles deviation of std::array from container tables.
        @@ -26748,6 +17704,17 @@ Batavia (2009-05): Move to Open, pending proposed wording from Dave for further review. +

        [ +2009-10 post-Santa Cruz: +]

        + + +
        +Tentatively NAD. We are not sure what has been addressed and what hasn't. +Recommend closing unless someone sorts this out into something more readable. +
        + +

        Proposed resolution:

        @@ -26759,11 +17726,11 @@ Move to Open, pending proposed wording from Dave for further review.

        1100. auto_ptr to unique_ptr conversion

        -

        Section: 20.8.9.2.1 [unique.ptr.single.ctor] Status: Review - Submitter: Howard Hinnant Opened: 2009-04-25 Last modified: 2009-08-01

        +

        Section: 20.8.14.2.1 [unique.ptr.single.ctor] Status: Ready + Submitter: Howard Hinnant Opened: 2009-04-25 Last modified: 2009-10-21

        View other active issues in [unique.ptr.single.ctor].

        View all other issues in [unique.ptr.single.ctor].

        -

        View all issues with Review status.

        +

        View all issues with Ready status.

        Discussion:

        Message c++std-lib-23182 led to a discussion in which several people @@ -26811,17 +17778,26 @@ tweaked for concepts removal.

        -I also moved the change from D.9 [depr.auto.ptr] -to 20.8.9.2 [unique.ptr.single] per the Editor's request +I also moved the change from D.10 [depr.auto.ptr] +to 20.8.14.2 [unique.ptr.single] per the Editor's request in Batavia (as long as I was making changes anyway). Set back to Review.
        +

        [ +2009-10 Santa Cruz: +]

        + + +
        +Move to Ready. +
        +

        Proposed resolution:

        -Add to 20.8.9.2 [unique.ptr.single]: +Add to 20.8.14.2 [unique.ptr.single]: 

        template <class T, class D>
@@ -26836,7 +17812,7 @@ public:

        -Add to 20.8.9.2.1 [unique.ptr.single.ctor]: +Add to 20.8.14.2.1 [unique.ptr.single.ctor]: 

        template <class U>
@@ -26872,139 +17848,13 @@ constructors shall not participate in overload resolution.
 
 
 
-
        
-
        1102. std::vector's reallocation policy still unclear
        
-
        Section: 23.3.6.2 [vector.capacity] Status: Review
- Submitter: Daniel Krügler Opened: 2009-04-20  Last modified: 2009-05-23
        
-
        View all other issues in [vector.capacity].
        
-
        View all issues with Review status.
        
-
        Discussion:
        
-
        
-I have the impression that even the wording of current draft
-N2857
-does insufficiently express the intent of vector's
-reallocation strategy. This has produced not too old library
-implementations which release memory in the clear() function
-and even modern articles about C++ programming cultivate
-the belief that clear is allowed to do exactly this. A typical
-example is something like this:
-
        
-
-
        const int buf_size = ...;
-std::vector<T> buf(buf_size);
-for (int i = 0; i < some_condition; ++i) {
-  buf.resize(buf_size);
-  write_or_read_data(buf.data());
-  buf.clear(); // Ensure that the next round get's 'zeroed' elements
-}
-
        
-
        
-where still the myth is ubiquitous that buf might be
-allowed to reallocate it's memory *inside* the for loop.
-
        
-
        
-IMO the problem is due to the fact, that
-
        
-
-
          
-
        1. 
-the actual memory-reallocation stability of std::vector
-is explained in 23.3.6.2 [vector.capacity]/3 and /6 which
-are describing just the effects of the reserve
-function, but in many examples (like above) there
-is no explicit call to reserve involved. Further-more
-23.3.6.2 [vector.capacity]/6 does only mention insertions
-and never mentions the consequences of erasing
-elements.
-
          2. 
-
        2. 
-
          
-the effects clause of std::vector's erase overloads in
-23.3.6.4 [vector.modifiers]/4 is silent about capacity changes. This
-easily causes a misunderstanding, because the counter
-parting insert functions described in 23.3.6.4 [vector.modifiers]/2
-explicitly say, that
-
          
-
          
-Causes reallocation if the new size is greater than the
-old capacity. If no reallocation happens, all the iterators
-and references before the insertion point remain valid.
-
          
-
          
-It requires a complex argumentation chain about four
-different places in the standard to provide the - possibly
-weak - proof that calling clear() also does never change
-the capacity of the std::vector container. Since std::vector
-is the de-facto replacement of C99's dynamic arrays this
-type is near to a built-in type and it's specification should
-be clear enough that usual programmers can trust their
-own reading.
-
          
-
          3. 
-
        
-
-
        [
-Batavia (2009-05):
-]
        
-
-
        
-
        
-Bill believes paragraph 1 of the proposed resolution is unnecessary
-because it is already implied (even if tortuously) by the current wording.
-
        
-
        
-Move to Review.
-
        
-
        
-
-
-
        Proposed resolution:
        
-
        [
-This is a minimum version. I also
-suggest that the wording explaining the allocation strategy
-of std::vector in 23.3.6.2 [vector.capacity]/3 and /6 is moved into
-a separate sub paragraph of 23.3.6.2 [vector.capacity] before
-any of the prototype's are discussed, but I cannot provide
-reasonable wording changes now
-]
        
-
-
-
          
-
        1. 
-
          
-Change 23.3.6.2 [vector.capacity]/6 as follows:
-
          
-
          
-It is guaranteed that no reallocation takes place during
-insertions or erasures that happen after a call
-to reserve() until the time when an insertion would make
-the size of the vector greater than the value of capacity().
-
          
-
          2. 
-
        2. 
-
          
-Change 23.3.6.4 [vector.modifiers]/4 as follows:
-
          
-
          
-Effects: The capacity shall remain unchanged and no reallocation shall
-happen.
-Invalidates iterators and references at or after the point
-of the erase.
-
          
-
          3. 
-
        
-
-
-
-
-
 
        
 
        1104. basic_ios::move should accept lvalues
        
-
        Section: 27.5.4.2 [basic.ios.members] Status: Review
- Submitter: Howard Hinnant Opened: 2009-04-25  Last modified: 2009-05-23
        
+
        Section: 27.5.4.2 [basic.ios.members] Status: Ready
+ Submitter: Howard Hinnant Opened: 2009-04-25  Last modified: 2009-10-20
        
 
        View other active issues in [basic.ios.members].
        
 
        View all other issues in [basic.ios.members].
        
-
        View all issues with Review status.
        
+
        View all issues with Ready status.
        
 
        Discussion:
        
 
        
 With the rvalue reference changes in
@@ -27050,6 +17900,15 @@ Move to Open.
 Added overload, moved to Review.
        +

        [ +2009 Santa Cruz: +]

        + + +
        +Move to Ready. +
        +

        Proposed resolution:

        @@ -27068,9 +17927,8 @@ void move(basic_ios&& rhs);

        1106. Multiple exceptions from connected shared_future::get()?

        -

        Section: 30.6.6 [future.shared_future] Status: Open +

        Section: 30.6.7 [future.shared_future] Status: Open Submitter: Thomas J. Gritzan Opened: 2009-04-03 Last modified: 2009-05-23

        -

        View other active issues in [future.shared_future].

        View all other issues in [future.shared_future].

        View all issues with Open status.

        Discussion:

        @@ -27120,7 +17978,7 @@ Move to Open.

        Proposed resolution:

        -Change 30.6.6 [future.shared_future]: +Change 30.6.7 [future.shared_future]: 

        const R& shared_future::get() const; 
@@ -27147,9 +18005,9 @@ stored. — end note]
 
 
        
 
        1108. thread.req.exception overly constrains implementations
        
-
        Section: 30.2.2 [thread.req.exception] Status: Open
- Submitter: Christopher Kohlhoff Opened: 2009-04-25  Last modified: 2009-05-23
        
-
        View all issues with Open status.
        
+
        Section: 30.2.2 [thread.req.exception] Status: Tentatively Ready
+ Submitter: Christopher Kohlhoff Opened: 2009-04-25  Last modified: 2009-10-26
        
+
        View all issues with Tentatively Ready status.
        
 
        Discussion:
        
 
        
 The current formulation of 30.2.2 [thread.req.exception]/2 reads:
@@ -27218,6 +18076,16 @@ Move to Open, and recommend the issue be deferred until after the next
 Committee Draft is issued.
        +

        [ +2009-10 post-Santa Cruz: +]

        + + +
        +Move to Tentatively Ready. +
        + +

        Proposed resolution:

        @@ -27254,13 +18122,13 @@ ec == errc::resource_unavailable_try_again // holds true

        1110. Is for_each overconstrained?

        -

        Section: 25.3.4 [alg.foreach] Status: Open - Submitter: Alisdair Meredith Opened: 2009-04-29 Last modified: 2009-05-23

        +

        Section: 25.2.4 [alg.foreach] Status: Open + Submitter: Alisdair Meredith Opened: 2009-04-29 Last modified: 2009-10-27

        View all other issues in [alg.foreach].

        View all issues with Open status.

        Discussion:

        -Quoting working paper for reference (25.3.4 [alg.foreach]): +Quoting working paper for reference (25.2.4 [alg.foreach]):

        @@ -27314,16 +18182,137 @@ Committee Draft is issued.

        +

        [ +2009-10-14 Daniel de-conceptified the proposed resolution. +]

        -

        Proposed resolution:

        + +

        -Change 25.2 [algorithms.syn] and 25.3.4 [alg.foreach]: +The note in 25.1 [algorithms.general]/9 already says the right thing: +

        +
        +Unless otherwise specified, algorithms that take function objects +as arguments are permitted to copy those function objects freely. +
        +

        +So we only need to ensure that the wording for for_each is sufficiently +clear, which is the intend of the following rewording. +

        +
        + +

        [ +2009-10-15 Daniel proposes: +]

        + + +
        +
          +
        • +

          +Add a new Requires clause just after the prototype declaration (25.2.4 [alg.foreach]): +

          +
          +

          +Requires: Function shall be MoveConstructible +( [moveconstructible]), CopyConstructible is not required. +

          +
          +
          • +
        • +

          +Change 25.2.4 [alg.foreach]/2 as indicated:

          -
          template<InputIterator Iter, Callable<auto, Iter::reference> Function>
-  requires CopyConstructible MoveConstructible<Function>
-  Function for_each(Iter first, Iter last, Function f);
-
          +
          +Returns: std::move(f). +
          +
          • +
        +
        + +

        [ +2009-10 post-Santa Cruz: +]

        + + +
        +Move to Tentatively Ready, using Daniel's wording without the portion +saying "CopyConstructible is not required". +
        + +

        [ +2009-10-27 Daniel adds: +]

        + + +
        +

        +I see that during the Santa Cruz meeting the originally proposed addition +

        + +
        +, CopyConstructible is not required. +
        + +

        +was removed. I don't think that this removal was a good idea. The combination +of 25.1 [algorithms.general]/9 +

        + +
        +[Note: Unless otherwise specified, algorithms that take function objects +as arguments are permitted to copy those function objects freely.[..] +
        + +

        +with the fact that CopyConstructible is a refinement MoveConstructible +makes it necessary that such an explicit statement is given. Even the +existence of the usage of std::move in the Returns clause doesn't +help much, because this would still be well-formed for a CopyConstructible +without move constructor. Let me add that the originally proposed +addition reflects current practice in the standard, e.g. 25.3.9 [alg.unique]/5 +usages a similar terminology. +

        + +

        +For similar wording need in case for auto_ptr see 973. +

        + +

        [ +Howard: Moved from Tentatively Ready to Open. +]

        + +
        + + + +

        Proposed resolution:

        +
          +
        • +

          +Add a new Requires clause just after the prototype declaration (25.2.4 [alg.foreach]): +

          +
          +

          +Requires: Function shall be MoveConstructible +( [moveconstructible]). +

          +
          +
          • +
        • +

          +Change 25.2.4 [alg.foreach]/2 as indicated: +

          + +
          +Returns: std::move(f). +
          +
          • +
        + + + @@ -27331,11 +18320,11 @@ Change 25.2 [algorithms.syn] and 25.3.4 [alg.foreach]:

        1112. bitsets and new style for loop

        -

        Section: 20.3.6 [template.bitset] Status: Open - Submitter: Alisdair Meredith Opened: 2009-05-06 Last modified: 2009-07-25

        +

        Section: 20.3.7 [template.bitset] Status: Tentatively NAD Future + Submitter: Alisdair Meredith Opened: 2009-05-06 Last modified: 2009-10-26

        View other active issues in [template.bitset].

        View all other issues in [template.bitset].

        -

        View all issues with Open status.

        +

        View all issues with Tentatively NAD Future status.

        Discussion:

        Std::bitset is a homogeneous container-like sequence of bits, yet it does @@ -27413,13 +18402,22 @@ Howard: I've replaced the proposed wording with Alisdair's suggestion. ]

        +

        [ +2009-10 post-Santa Cruz: +]

        + + +
        +Mark as Tentatively NAD Future due to the loss of concepts. +
        +

        Proposed resolution:

        1. -Modify the section 20.3.6 [template.bitset] <bitset> synopsis by adding +Modify the section 20.3.7 [template.bitset] <bitset> synopsis by adding the following at the end of the synopsis: 

          
@@ -27434,7 +18432,7 @@ template<size_t N> unspecified-2 end(const bitset<N>&);
 
        2. 
 
          
 Add a new section "bitset range access" [bitset.range]
-after the current section 20.3.6.3 [bitset.operators] with the following series of
+after the current section 20.3.7.3 [bitset.operators] with the following series of
 paragraphs:
 
          
 
          
@@ -27442,10 +18440,10 @@ paragraphs:
 
 1.  In the begin and end function templates that follow, unspecified-1
 is a type that meets the requirements of a mutable random access
-iterator (24.2.6 [random.access.iterators]) whose value_type is bool and
+iterator (24.2.5 [random.access.iterators]) whose value_type is bool and
 whose reference type is bitset<N>::reference.
 unspecified-2 is a type that meets the requirements of a constant
-random access iterator (24.2.6 [random.access.iterators]) whose value_type
+random access iterator (24.2.5 [random.access.iterators]) whose value_type
 is bool and whose reference type is bool.
 
 
          
@@ -27484,11 +18482,11 @@ bitset.
 
 
          
 
          1113. bitset::to_string could be simplified
          
-
          Section: 20.3.6 [template.bitset] Status: Open
- Submitter: Alisdair Meredith Opened: 2009-05-09  Last modified: 2009-05-23
          
+
          Section: 20.3.7 [template.bitset] Status: Tentatively Ready
+ Submitter: Alisdair Meredith Opened: 2009-05-09  Last modified: 2009-10-26
          
 
          View other active issues in [template.bitset].
          
 
          View all other issues in [template.bitset].
          
-
          View all issues with Open status.
          
+
          View all issues with Tentatively Ready status.
          
 
          Discussion:
          
 
          
 In 853 our resolution is changing the signature by adding two
@@ -27512,13 +18510,23 @@ and look at the issue again after 
 
        3. 
 
          
-In 20.3.6 [template.bitset]/1 (class bitset) ammend:
+In 20.3.7 [template.bitset]/1 (class bitset) ammend:
 
          
 
          template <class charT = char,
             class traits = char_traits<charT>,
@@ -27534,7 +18542,7 @@ basic_string<char, char_traits<char>, allocator<char> > to_str
 
          4. 
 
        4. 
 
          
-In 20.3.6.2 [bitset.members] prior to p35 ammend:
+In 20.3.7.2 [bitset.members] prior to p35 ammend:
 
          
 
          template <class charT = char,
             class traits = char_traits<charT>,
@@ -27544,7 +18552,7 @@ In 20.3.6.2 [bitset.members] prior to p35 ammend:
 
          
 
          5. 
 
        5. 
-Strike 20.3.6.2 [bitset.members] paragraphs 37 -> 39 (including signature
+Strike 20.3.7.2 [bitset.members] paragraphs 37 -> 39 (including signature
 above 37)
 
          6.
        @@ -27556,11 +18564,10 @@ above 37)

        1114. Type traits underspecified

        -

        Section: 20.6 [meta] Status: Open - Submitter: Daniel Krügler Opened: 2009-05-12 Last modified: 2009-05-23

        -

        View other active issues in [meta].

        +

        Section: 20.6 [meta] Status: Tentatively Ready + Submitter: Daniel Krügler Opened: 2009-05-12 Last modified: 2009-10-26

        View all other issues in [meta].

        -

        View all issues with Open status.

        +

        View all issues with Tentatively Ready status.

        Discussion:

        @@ -27608,13 +18615,23 @@ Move to Open.

        +

        [ +2009-10 post-Santa Cruz: +]

        + + +
        +Move to Tentatively Ready. +
        + +

        Proposed resolution:

        [ The usage of the notion of a BaseCharacteristic below might be useful in other places - e.g. to define the base class relation in -20.7.5 [refwrap], 20.7.15 [func.memfn], or 20.7.16.2 [func.wrap.func]. +20.7.5 [refwrap], 20.7.14 [func.memfn], or 20.7.15.2 [func.wrap.func]. In this case it's definition should probably be moved to Clause 17 ]

        @@ -27685,11 +18702,10 @@ corresponding condition is true, otherwise false_type.

        1115. va_copy missing from Standard macros table

        -

        Section: C.2 [diff.library] Status: New - Submitter: Miles Zhao Opened: 2009-05-23 Last modified: 2009-05-23

        -

        View other active issues in [diff.library].

        +

        Section: C.2 [diff.library] Status: Tentatively NAD Editorial + Submitter: Miles Zhao Opened: 2009-05-23 Last modified: 2009-10-26

        View all other issues in [diff.library].

        -

        View all issues with New status.

        +

        View all issues with Tentatively NAD Editorial status.

        Discussion:

        In "Table 122 -- Standard macros" of C.2 [diff.library], which lists the 56 macros @@ -27697,6 +18713,17 @@ inherited from C library, va_copy seems to be missing. But in "Table 21 -- Header <cstdarg> synopsis" (18.10 [support.runtime]), there is.

        +

        [ +2009-10 post-Santa Cruz: +]

        + + +
        +Mark as Tentatively NAD Editorial, if Pete disagrees, Howard +will move to Tentatively Ready +
        + +

        Proposed resolution:

        @@ -27707,140 +18734,13 @@ Add va_copy to Table 122 -- Standard macros in C.2 [diff.library]. -

        -

        1116. Literal constructors for tuple

        -

        Section: 20.5.2 [tuple.tuple] Status: New - Submitter: Alisdair Meredith Opened: 2009-05-23 Last modified: 2009-05-24

        -

        View all other issues in [tuple.tuple].

        -

        View all issues with New status.

        -

        Discussion:

        -

        -It is not currently possible to construct tuple literal values, -even if the elements are all literal types. This is because parameters -are passed to constructor by reference. -

        -

        -An alternative would be to pass all constructor arguments by value, where it -is known that *all* elements are literal types. This can be determined with -concepts, although note that the negative constraint really requires -factoring out a separate concept, as there is no way to provide an 'any of -these fails' constraint inline. -

        -

        -Note that we will have similar issues with pair (and -tuple constructors from pair) although I am steering -clear of that class while other constructor-related issues settle. -

        - - -

        Proposed resolution:

        -

        -Ammend the tuple class template declaration in 20.5.2 [tuple.tuple] as -follows -

        - -
        -

        -Add the following concept: -

        - -
        auto concept AllLiteral< typename ... Types > {
-  requires LiteralType<Types>...;
-}
-
        - -

        -ammend the constructor -

        - -
        template <class... UTypes>
-  requires AllLiteral<Types...>
-        && Constructible<Types, UTypes>...
-  explicit tuple(UTypes...);
-
-template <class... UTypes>
-  requires !AllLiteral<Types...>
-        && Constructible<Types, UTypes&&>...
-  explicit tuple(UTypes&&...);
-
        - -

        -ammend the constructor -

        - -
        template <class... UTypes>
-  requires AllLiteral<Types...>
-        && Constructible<Types, UTypes>...
-  tuple(tuple<UTypes...>);
-
-template <class... UTypes>
-  requires !AllLiteral<Types...>
-        && Constructible<Types, const UTypes&>...
-  tuple(const tuple<UTypes...>&);
-
        - -
        - -

        -Update the same signatures in 20.5.2.1 [tuple.cnstr], paras 3 and 5. -

        - - - - - -
        -

        1117. tuple copy constructor

        -

        Section: 20.5.2.1 [tuple.cnstr] Status: New - Submitter: Alisdair Meredith Opened: 2009-05-23 Last modified: 2009-05-30

        -

        View other active issues in [tuple.cnstr].

        -

        View all other issues in [tuple.cnstr].

        -

        View all issues with New status.

        -

        Discussion:

        -

        -The copy constructor for the tuple template is constrained. This seems an -unusual strategy, as the copy constructor will be implicitly deleted if the -constraints are not met. This is exactly the same effect as requesting an -=default; constructor. The advantage of the latter is that it retains -triviality, and provides support for tuples as literal types if issue -1116 is also accepted. -

        -

        -Actually, it might be worth checking with core if a constrained copy -constructor is treated as a constructor template, and as such does not -suppress the implicit generation of the copy constructor which would hide -the template in this case. -

        - -

        [ -2009-05-27 Daniel adds: -]

        - - -
        -This would solve one half of the suggested changes in 801. -
        - - -

        Proposed resolution:

        -

        -Change 20.5.2 [tuple.tuple] and 20.5.2.1 [tuple.cnstr] p4: -

        - -
        requires CopyConstructible<Types>... tuple(const tuple&) = default;
-
        - - - - -

        1118. tuple query APIs do not support cv-qualification

        -

        Section: 20.5.2.3 [tuple.helper] Status: New - Submitter: Alisdair Meredith Opened: 2009-05-23 Last modified: 2009-05-25

        +

        Section: 20.5.2.5 [tuple.helper] Status: Open + Submitter: Alisdair Meredith Opened: 2009-05-23 Last modified: 2009-10-26

        View other active issues in [tuple.helper].

        View all other issues in [tuple.helper].

        -

        View all issues with New status.

        +

        View all issues with Open status.

        Discussion:

        The APIs tuple_size and tuple_element do not support @@ -27915,6 +18815,16 @@ though.

        +

        [ +2009-10 post-Santa Cruz: +]

        + + +
        +Move to Open, Alisdair to provide wording. Once wording is +provided, Howard will move to Review. +
        +

        Proposed resolution:

        @@ -27940,7 +18850,7 @@ template <size_t I, VariableType... Types>

        -Add to 20.5.2.3 [tuple.helper] +Add to 20.5.2.5 [tuple.helper]

        [ (note that this solution relies on 'metafunction forwarding' to inherit the @@ -27975,11 +18885,11 @@ public:

        1119. tuple query APIs do not support references

        -

        Section: 20.5.2.3 [tuple.helper] Status: New - Submitter: Alisdair Meredith Opened: 2009-05-23 Last modified: 2009-05-24

        +

        Section: 20.5.2.5 [tuple.helper] Status: Open + Submitter: Alisdair Meredith Opened: 2009-05-23 Last modified: 2009-10-26

        View other active issues in [tuple.helper].

        View all other issues in [tuple.helper].

        -

        View all issues with New status.

        +

        View all issues with Open status.

        Discussion:

        The tuple query APIs tuple_size and @@ -27999,40 +18909,17 @@ Core/Evolution. Note that we have the same problem in numeric_limits.

        - -

        Proposed resolution:

        +

        [ +2009-10 post-Santa Cruz: +]

        +
        +Move to Open. Alisdair to provide wording. +
        -
        -

        1120. New type trait - remove_all

        -

        Section: 20.6 [meta] Status: New - Submitter: Alisdair Meredith Opened: 2009-05-23 Last modified: 2009-05-24

        -

        View other active issues in [meta].

        -

        View all other issues in [meta].

        -

        View all issues with New status.

        -

        Discussion:

        -

        -Sometimes it is necessary to remove all qualifiers from a type before -passing on to a further API. A good example would be calling the -tuple query APIs tuple_size or tuple_element -with a deduced type inside a function template. If the deduced type is -cv-qualified or a reference then the call will fail. The solution is to -chain calls to -remove_cv<remove_reference<T>::type>::type, and -note that the order matters. -

        -

        -Suggest it would be helpful to add a new type trait, -remove_all, that removes all top-level qualifiers from a type -i.e. cv-qualification and any references. Define the term in such a way -that if additional qualifiers are added to the language, then -remove_all is defined as stripping those as well. -

        - -

        Proposed resolution:

        @@ -28041,10 +18928,10 @@ that if additional qualifiers are added to the language, then

        1121. Support for multiple arguments

        -

        Section: 20.4.2 [ratio.arithmetic] Status: New - Submitter: Alisdair Meredith Opened: 2009-05-25 Last modified: 2009-05-25

        +

        Section: 20.4.2 [ratio.arithmetic] Status: Tentatively NAD Future + Submitter: Alisdair Meredith Opened: 2009-05-25 Last modified: 2009-11-02

        View all other issues in [ratio.arithmetic].

        -

        View all issues with New status.

        +

        View all issues with Tentatively NAD Future status.

        Discussion:

        Both add and multiply could sensibly be called with more than two arguments. @@ -28064,86 +18951,117 @@ proposed for 921 would proceed to Ready as planned, and the +multi-paramater add/multiply templates should be renamed as +ratio_sum and ratio_product to avoid the problem +mixing template aliases with partial specializations.

        -
        // ratio arithmetic
-template <class R1, class R2, class ... RList> struct ratio_add;
-template <class R1, class R2> struct ratio_subtract;
-template <class R1, class R2, class ... RList> struct ratio_multiply;
-template <class R1, class R2> struct ratio_divide;
-
        -

        -20.4.2 [ratio.arithmetic] p1: change +It was also suggested to close this issue as NAD Future as it does not +correspond directly to any NB comment. NBs are free to submit a +specific comment (and re-open) in CD2 though.

        -
        template <class R1, class R2, class ... RList> struct ratio_add
-  : ratio_add< R1, ratio_add<R2, RList...>> {
-};
-
-template <class R1, class R2> struct ratio_add<R1, R2> {
-  typedef see below type;
-};
-
        - -

        -20.4.2 [ratio.arithmetic] p3: change +Walter Brown also had concerns on better directing the order of +evaluation to avoid overflows if we do proceed for 0x rather than TR1, +so wording may not be complete yet.

        -
        template <class R1, class R2, class ... RList> struct ratio_multiply
-  : ratio_multiply< R1, ratio_ multiply <R2, RList...>> {
-};
-
-template <class R1, class R2> struct ratio_ multiply<R1, R2> {
-  typedef see below type;
-};
-
        +

        [ +Alisdair updates wording. +]

        + + +

        [ +2009-10-30 Howard: +]

        +
        +Moved to Tentatively NAD Future after 5 positive votes on c++std-lib. +
        -
        -

        1122. Ratio values should be constexpr

        -

        Section: 20.4.1 [ratio.ratio] Status: New - Submitter: Alisdair Meredith Opened: 2009-05-25 Last modified: 2009-05-25

        -

        View other active issues in [ratio.ratio].

        -

        View all other issues in [ratio.ratio].

        -

        View all issues with New status.

        -

        Discussion:

        -

        -The values num and den in the ratio template -should be declared constexpr. -

        -

        Proposed resolution:

        +

        -20.4.1 [ratio.ratio] +Add the following type traits to p3 20.4 [ratio]

        -
        namespace std {
-  template <intmax_t N, intmax_t D = 1>
-  class ratio {
-  public:
-    static constexpr intmax_t num;
-    static constexpr intmax_t den;
-  };
-}
+
        // ratio arithmetic
+template <class R1, class R2> struct ratio_add;
+template <class R1, class R2> struct ratio_subtract;
+template <class R1, class R2> struct ratio_multiply;
+template <class R1, class R2> struct ratio_divide;
+template <class R1, class ... RList> struct ratio_sum;
+template <class R1, class ... RList> struct ratio_product;
 
        
 
+
        
+after 20.4.2 [ratio.arithmetic] p1: add
+
        
+
+
        template <class R1, class ... RList> struct ratio_sum; // declared, never defined
+
+template <class R1> struct ratio_sum<R1> : R1 {};
+
        
+
+
        
+Requires: R1 is a specialization of class template ratio
+
        
+
+
        template <class R1, class R2, class ... RList> 
+ struct ratio_sum<R1, R2, RList...>
+   : ratio_add< R1, ratio_sum<R2, RList...>> {
+};
+
        
+
+
        
+Requires: R1 and each element in parmater pack
+RList is a specialization of class template ratio
+
        
+
        
+
+
        
+after 20.4.2 [ratio.arithmetic] p3: add
+
        
+
+
        template <class R1, class ... RList> struct ratio_product; // declared, never defined
+
+template <class R1> struct ratio_product<R1> : R1 {};
+
        
+
+
        
+Requires: R1 is a specialization of class template ratio
+
        
+
+
        template <class R1, class R2, class ... RList> 
+ struct ratio_sum<R1, R2, RList...>
+   : ratio_add< R1, ratio_product<R2, RList...>> {
+};
+
        
+
+
        
+Requires: R1 and each element in parmater pack
+RList is a specialization of class template ratio
+
        
+
        
+
+
+
 
 
 
@@ -28151,10 +19069,10 @@ should be declared constexpr.
 
 
        
 
        1123. no requirement that standard streams be flushed
        
-
        Section: 27.5.2.1.6 [ios::Init] Status: New
- Submitter: James Kanze Opened: 2009-05-14  Last modified: 2009-05-30
        
+
        Section: 27.5.2.1.6 [ios::Init] Status: Ready
+ Submitter: James Kanze Opened: 2009-05-14  Last modified: 2009-10-20
        
 
        View all other issues in [ios::Init].
        
-
        View all issues with New status.
        
+
        View all issues with Ready status.
        
 
        Discussion:
        
 
        
 As currently formulated, the standard doesn't require that there 
@@ -28220,6 +19138,17 @@ Perhaps some words somewhere to the effect that all
 would be in order. 
 
        
 
+
        [
+2009 Santa Cruz:
+]
        
+
+
+
        
+Moved to Ready.  Some editorial changes are expected (in addition to the
+proposed wording) to remove init_cnt from Init.
+
        
+
+
 
 
        Proposed resolution:
        
 
        
@@ -28340,10 +19269,10 @@ return (*this);
 
 
        
 
        1126. istreambuff_iterator::equal needs a const & parameter
        
-
        Section: 24.6.3.5 [istreambuf.iterator::equal] Status: New
- Submitter: Alisdair Meredith Opened: 2009-05-28  Last modified: 2009-05-30
        
+
        Section: 24.6.3.5 [istreambuf.iterator::equal] Status: Tentatively Ready
+ Submitter: Alisdair Meredith Opened: 2009-05-28  Last modified: 2009-11-02
        
 
        View all other issues in [istreambuf.iterator::equal].
        
-
        View all issues with New status.
        
+
        View all issues with Tentatively Ready status.
        
 
        Discussion:
        
 
        
 The equal member function of istreambuf_iterator is
@@ -28360,6 +19289,15 @@ The proposed wording is consistent with 1129. istream(buf)_iterator should support literal sentinel value
-
        Section: 24.6.1.1 [istream.iterator.cons], 24.6.3 [istreambuf.iterator] Status: New
- Submitter: Alisdair Meredith Opened: 2009-05-30  Last modified: 2009-06-09
        
-
        View all issues with New status.
        
-
        Discussion:
        
-
        
-istream_iterator and istreambuf_iterator should support literal sentinel
-values.  The default constructor is frequently used to terminate ranges, and
-could easily be a literal value for istreambuf_iterator, and
-istream_iterator when iterating value types.  A little more work using a
-suitably sized/aligned char-array for storage (or an updated component like
-boost::optional proposed for TR2) would allow istream_iterator to support
-constexpr default constructor in all cases, although we might leave this
-tweak as a QoI issue.  Note that requiring constexpr be supported also
-allows us to place no-throw guarantees on this constructor too.
-
        
-
-
        [
-2009-06-02 Daniel adds:
-]
        
-
-
-
        
-
        
-I agree with the usefulness of the issue suggestion, but we need
-to ensure that istream_iterator can satisfy be literal if needed.
-Currently this is not clear, because 24.6.1 [istream.iterator]/3 declares
-a copy constructor and a destructor and explains their semantic in
-24.6.1.1 [istream.iterator.cons]/3+4.
-
        
-
        
-The prototype semantic specification is ok (although it seems
-somewhat redundant to me, because the semantic doesn't say
-anything interesting in both cases), but for support of trivial class
-types we also need a trivial copy constructor and destructor as of
-9 [class]/6. The current non-informative specification of these
-two special members suggests to remove their explicit declaration
-in the class and add explicit wording that says that if T is
-trivial a default constructed iterator is also literal, alternatively it
-would be possible to mark both as defaulted and add explicit
-(memberwise) wording that guarantees that they are trivial.
-
        
-
        
-Btw.: I'm quite sure that the istreambuf_iterator additions to
-ensure triviality are not sufficient as suggested, because the
-library does not yet give general guarantees that a defaulted
-special member declaration makes this member also trivial.
-Note that e.g. the atomic types do give a general statement!
-
        
-
        
-Finally there is a wording issue: There does not exist something
-like a "literal constructor". The core language uses the term
-"constexpr constructor" for this.
-
        
-
        
-Suggestion:
-
        
-
          
-
        1. 
-
          
-Change 24.6.1 [istream.iterator]/3 as indicated:
-
          
-
          constexpr istream_iterator();
-istream_iterator(istream_type& s);
-istream_iterator(const istream_iterator<T,charT,traits,Distance>& x) = default;
-~istream_iterator() = default;
-
          
-
          2. 
-
        2. 
-
          
-Change 24.6.1.1 [istream.iterator.cons]/1 as indicated:
-
          
-
          constexpr istream_iterator();
-
          
-
          
--1- Effects: Constructs the end-of-stream iterator. If T is a literal type,
-then this constructor shall be a constexpr constructor.
-
          
-
          
-
          3. 
-
        3. 
-
          
-Change 24.6.1.1 [istream.iterator.cons]/3 as indicated:
-
          
-
          istream_iterator(const istream_iterator<T,charT,traits,Distance>& x) = default;
-
          
-
          
--3- Effects: Constructs a copy of x. If T is a literal type, then
-this constructor shall be a trivial copy constructor.
-
          
-
          
-
          4. 
-
        4. 
-
          
-Change 24.6.1.1 [istream.iterator.cons]/4 as indicated:
-
          
-
-
          ~istream_iterator() = default;
-
          
-
          
--4- Effects: The iterator is destroyed. If T is a literal type, then
-this destructor shall be a trivial
-destructor.
-
          
-
          
-
          5. 
-
        5. 
-
          
-Change 24.6.3 [istreambuf.iterator] before p. 1 as indicated:
-
          
-
-
          constexpr istreambuf_iterator() throw();
-istreambuf_iterator(const istreambuf_iterator&)  throw() = default;
-~istreambuf_iterator()  throw() = default;
-
          
-
          6. 
-
        6. 
-
          
-Change 24.6.3 [istreambuf.iterator]/1 as indicated:
-
          
-
          
-[..] The default constructor istreambuf_iterator() and the constructor
-istreambuf_iterator(0) both
-construct an end of stream iterator object suitable for use as an
-end-of-range. All
-specializations of istreambuf_iterator shall have a trivial copy
-constructor, a constexpr default
-constructor and a trivial destructor.
-
          
-
          7. 
-
        
-
        
-
-
-
        Proposed resolution:
        
-
        
-24.6.1 [istream.iterator] para 3
-
        
-
-
        constexpr istream_iterator();
-
        
-
-
        
-24.6.1.1 [istream.iterator.cons]
-
        
-
-
        constexpr istream_iterator();
-
        
-
        
--1- Effects: Constructs the end-of-stream iterator.
-If T is a literal type, then this constructor shall
-be a literal constructor.
-
        
-
        
-
-
        
-24.6.3 [istreambuf.iterator]
-
        
-
-
        constexpr istreambuf_iterator() throw();
-
        
-
-
-
-
-
-
 
        
 
        1130. copy_exception name misleading
        
-
        Section: 18.8.5 [propagation] Status: New
- Submitter: Peter Dimov Opened: 2009-05-13  Last modified: 2009-06-02
        
+
        Section: 18.8.5 [propagation] Status: Review
+ Submitter: Peter Dimov Opened: 2009-05-13  Last modified: 2009-10-20
        
 
        View other active issues in [propagation].
        
 
        View all other issues in [propagation].
        
-
        View all issues with New status.
        
+
        View all issues with Review status.
        
 
        Discussion:
        
 
        
 The naming of std::copy_exception misleads almost everyone
@@ -28645,6 +19415,18 @@ exception_ptr make_exception_ptr<exception_ptr>(exception_ptr e) = delete;
        +

        [ +2009 Santa Cruz: +]

        + + +
        +Move to Review for the time being. The subgroup thinks this is a good +idea, but doesn't want to break compatibility unnecessarily if someone +is already shipping this. Let's talk to Benjamin and PJP tomorrow to +make sure neither objects. +
        +

        Proposed resolution:

        @@ -28754,216 +19536,10 @@ transformations 20.6.7 [meta.trans.other], as follows: -
        -

        1132. JP-30: nested exceptions

        -

        Section: 18.8.6 [except.nested] Status: New - Submitter: Seiji Hayashida Opened: 2009-06-01 Last modified: 2009-06-02

        -

        View other active issues in [except.nested].

        -

        View all other issues in [except.nested].

        -

        View all issues with New status.

        -

        Discussion:

        -

        Addresses JP 30

        - -

        -C++0x nested_exception cannot handle a structured exception well. The -following codes show two types of tree structured exception handling. -

        -

        -The first one is based on nested_exception in C++0x, -while the second one is based on my library trickerr.h (in Japanese). -http://tricklib.com/cxx/dagger/trickerr.h -

        -

        -Assume that Function A() calls two sub functions A_a() and A_b(), both might -throw tree structured exceptions, and A_b() must be called even if A_a() -throws an exception. -

        -

        -List A (code of tree structured exception handling based on nested_exception -in C++0x) -

        - -
        void A()
-{
-    try
-    {
-        std::vector<exception_ptr> exception_list;
-        try
-        {
-            // A_a() does a similar processing as A().
-            A_a();
-        }
-        catch(...)
-        {
-            exception_list.push_back(current_exception());
-        }
-
-        // ***The processing A() has to do even when A_a() fails. ***
-        try
-        {
-            // A_b() does a similar processing as A().
-            A_b();
-        }
-        catch(...)
-        {
-            exception_list.push_back(current_exception());
-        }
-        if (!exception_list.empty())
-        {
-            throw exception_list;
-        }
-    }
-    catch(...)
-    {
-        throw_with_nested(A_exception("someone error"));
-    }
-}
-void print_tree_exception(exception_ptr e, const std::string & indent ="")
-{
-    const char * indent_unit = " ";
-    const char * mark = "- ";
-    try
-    {
-        rethow_exception(e);
-    }
-    catch(const std::vector<exception_ptr> e)
-    {
-        for(std::vector<exception_ptr>::const_iterator i = e.begin(); i!=e.end(); ++i)
-        {
-            print_tree_exception(i, indent);
-        }
-    }
-    catch(const std::nested_exception  e)
-    {
-        print_tree_exception(evil_i(e), indent +indent_unit);
-    }
-    catch(const std::exception e)
-    {
-        std::cout << indent << mark << e.what() << std::endl;
-    }
-    catch(...)
-    {
-        std::cout << indent << mark << "unknown exception" << std::endl;
-    }
-}
-int main(int, char * [])
-{
-    try
-    {
-        A();
-    }
-    catch()
-    {
-        print_tree_exception(current_exception());
-    }
-    return EXIT_SUCCESS;
-}
-
        - -

        -List B ( code of tree structured exception handling based on trickerr.h. ) -"trickerr.h" (in Japanese), refer to: -http://tricklib.com/cxx/dagger/trickerr.h. -

        - -
        void A()
-{
-    tricklib::error_listener_type error_listener;
-    // A_a() is like A(). A_a() can throw tree structured exception.
-    A_a();
-
-    // *** It must do process so that A_a() throws exception in A(). ***
-    // A_b() is like A(). A_b() can throw tree structured exception.
-    A_b();
-
-    if (error_listener.has_error()) // You can write this "if block" in destructor
-                                    //  of class derived from error_listener_type.
-    {
-        throw_error(new A_error("someone error",error_listener.listener_off().extract_pending_error()));
-    }
-}
-void print_tree_error(const tricklib::error_type &a_error, const std::string & indent = "")
-{
-    const char * indent_unit = " ";
-    const char * mark = "- ";
-
-    tricklib::error_type error = a_error;
-    while(error)
-    {
-        std::cout << indent << mark << error->message << std::endl;
-        if (error->children)
-        {
-            print_tree_error(error->children, indent +indent_unit);
-        }
-        error = error->next;
-    }
-}
-int main(int, char * [])
-{
-    tricklib::error_thread_power error_thread_power_on; // This object is necessary per thread.
-
-    try
-    {
-        A();
-    }
-    catch(error_type error)
-    {
-        print_tree_error(error);
-    }
-    catch(...)
-    {
-        std::cout << "- unknown exception" << std::endl;
-    }
-    return EXIT_SUCCESS;
-}
-
        - -

        -Prospect -

        -

        -We will focus on the method A() since the other methods, also main(), occur -only once respectively. -

        - -
          -
        • - In the List A above (of the nested exception handling), it is hard to - find out an active reason to use the nested exception handling at this - scene. Rather, we can take a simpler description by throwing the entire - exception_list directly to the top level. -
          • -
        • - The code in the same example gives us a kind of redundant impression, - which might have come from the fact that the try-throw-catch framework does - not assume a tree structured exception handling. -
          • -
        - -

        -According to the above observation, we cannot help concluding that it is not -so easy to use the nested_exception handling as a tree structured exception -handling mechanism in a practical sense. -

        -

        -This text is based on the web page below (in Japanese). -http://d.hatena.ne.jp/wraith13/20081231/1230715424 -

        - - -

        Proposed resolution:

        -

        -

        - - - - -

        1133. Does N2844 break current specification of list::splice?

        Section: 23.3.3.5 [forwardlist.ops], 23.3.4.4 [list.ops] Status: New - Submitter: Alisdair Meredith Opened: 2009-05-09 Last modified: 2009-06-09

        -

        View other active issues in [forwardlist.ops].

        + Submitter: Alisdair Meredith Opened: 2009-05-09 Last modified: 2009-10-27

        View all other issues in [forwardlist.ops].

        View all issues with New status.

        Discussion:

        @@ -29001,15 +19577,15 @@ void splice(const_iterator position, list<T,Alloc>&& x, Possible resolutions:

        -Option A. Add an additional (non-const) lvalue-reference +Option A. Add an additional (non-const) lvalue-reference overload in each case

        -Option B. Change rvalue reference back to (non-const) +Option B. Change rvalue reference back to (non-const) lvalue-reference overload in each case

        -Option C. Add an additional (non-const) lvalue-reference +Option C. Add an additional (non-const) lvalue-reference overload in just the std::list cases

        @@ -29025,8 +19601,60 @@ is a more explicit interface. I don't think that will fly though! See the thread starting with c++std-lib-23725 for more discussion.

        +

        [ +2009-10-27 Christopher Jefferson provides proposed wording for Option C. +]

        + +

        Proposed resolution:

        +

        +In 23.3.4 [list] +

        + +

        +Add lvalue overloads before rvalue ones: +

        + +
        void splice(const_iterator position, list<T,Allocator>& x);
+void splice(const_iterator position, list<T,Allocator>&& x);
+void splice(const_iterator position, list<T,Allocator>& x, const_iterator i);
+void splice(const_iterator position, list<T,Allocator>&& x, const_iterator i);
+void splice(const_iterator position, list<T,Allocator>& x,
+            const_iterator first, const_iterator last);
+void splice(const_iterator position, list<T,Allocator>&& x,
+            const_iterator first, const_iterator last);
+
        + +

        +In 23.3.4.4 [list.ops], similarly add lvalue overload before each rvalue one: +

        +

        +(After paragraph 2) +

        + +
        void splice(const_iterator position, list<T,Allocator>& x);
+void splice(const_iterator position, list<T,Allocator>&& x);
+
        + +

        +(After paragraph 6) +

        + +
        void splice(const_iterator position, list<T,Allocator>& x, const_iterator i);
+void splice(const_iterator position, list<T,Allocator>&& x, const_iterator i);
+
        + +

        +(After paragraph 10) +

        + +
        void splice(const_iterator position, list<T,Allocator>& x,
+            const_iterator first, const_iterator last);
+void splice(const_iterator position, list<T,Allocator>&& x,
+            const_iterator first, const_iterator last);
+
        + @@ -29034,9 +19662,9 @@ See the thread starting with c++std-lib-23725 for more discussion.

        1134. Redundant specification of stdint.h, fenv.h, tgmath.h, and maybe complex.h

        -

        Section: 18.4.2 [stdinth], 26.3.2 [fenv], 26.8 [c.math], 26.4.11 [cmplxh] Status: New - Submitter: Robert Klarer Opened: 2009-05-26 Last modified: 2009-06-14

        -

        View all issues with New status.

        +

        Section: 18.4.2 [stdinth], 26.3.2 [fenv], 26.8 [c.math], 26.4.11 [cmplxh] Status: Ready + Submitter: Robert Klarer Opened: 2009-05-26 Last modified: 2009-10-20

        +

        View all issues with Ready status.

        Discussion:

        This is probably editorial. @@ -29070,6 +19698,16 @@ mentioned in 3.9.1 [basic.fundamental] /5. It guess it should refer to <cstdint> instead. +

        [ +2009 Santa Cruz: +]

        + + +
        +Real issue. Maybe just editorial, maybe not. Move to Ready. +
        + +

        Proposed resolution:

        @@ -29096,11 +19734,11 @@ Remove the section 26.4.11 [cmplxh].

        1135. exception_ptr should support contextual conversion to bool

        -

        Section: 18.8.5 [propagation] Status: New - Submitter: Daniel Krügler Opened: 2007-06-06 Last modified: 2009-06-09

        +

        Section: 18.8.5 [propagation] Status: Ready + Submitter: Daniel Krügler Opened: 2007-06-06 Last modified: 2009-10-20

        View other active issues in [propagation].

        View all other issues in [propagation].

        -

        View all issues with New status.

        +

        View all issues with Ready status.

        Discussion:

        As of @@ -29127,6 +19765,18 @@ context like so: } +

        [ +2009 Santa Cruz: +]

        + + +
        +Move to Ready. Note to editor: considering putting in a cross-reference +to 4 [conv], paragraph 3, which defines the phrase +"contextually converted to bool". +
        + +

        Proposed resolution:

        @@ -29148,11 +19798,11 @@ enumeration type or to pointer type.

        1136. Incomplete specification of nested_exception::rethrow_nested()

        -

        Section: 18.8.6 [except.nested] Status: New - Submitter: Daniel Krügler Opened: 2007-06-06 Last modified: 2009-06-09

        +

        Section: 18.8.6 [except.nested] Status: Ready + Submitter: Daniel Krügler Opened: 2007-06-06 Last modified: 2009-10-20

        View other active issues in [except.nested].

        View all other issues in [except.nested].

        -

        View all issues with New status.

        +

        View all issues with Ready status.

        Discussion:

        It was recently mentioned in a newsgroup article @@ -29192,6 +19842,16 @@ be consistent to the behavior of a throw; statement when no exception is being handled.

        +

        [ +2009 Santa Cruz: +]

        + + +
        +Move to Ready. +
        + +

        Proposed resolution:

        @@ -29304,10 +19964,10 @@ the effectively promoted arguments.

        -

        1138. unusal return value for operator+

        -

        Section: 21.4.8.1 [string::op+] Status: New - Submitter: Alisdair Meredith Opened: 2009-06-12 Last modified: 2009-06-15

        -

        View all issues with New status.

        +

        1138. unusual return value for operator+

        +

        Section: 21.4.8.1 [string::op+] Status: Tentatively Ready + Submitter: Alisdair Meredith Opened: 2009-06-12 Last modified: 2009-11-05

        +

        View all issues with Tentatively Ready status.

        Discussion:

        Many of the basic_string operator+ overloads return an rvalue-reference. Is @@ -29329,6 +19989,20 @@ and I'm not sure about: 

        auto s = string{"x"} + string{y};
        +

        [ +2009-10-11 Howard updated Returns: clause for each of these. +]

        + + +

        [ +2009-11-05 Howard adds: +]

        + + +
        +Moved to Tentatively Ready after 5 positive votes on c++std-lib. +
        +

        Proposed resolution:

        @@ -29384,36 +20058,58 @@ template<class charT, class traits, class Allocator> basic_string<charT,traits,Allocator>&& operator+(basic_string<charT,traits,Allocator>&& lhs, const basic_string<charT,traits,Allocator>& rhs); - -template<class charT, class traits, class Allocator> + +

        +Returns: std::move(lhs.append(rhs)) +
        +
        template<class charT, class traits, class Allocator>
   basic_string<charT,traits,Allocator>&&
     operator+(const basic_string<charT,traits,Allocator>& lhs,
               basic_string<charT,traits,Allocator>&& rhs);
-
-template<class charT, class traits, class Allocator>
+
        +
        +Returns: std::move(rhs.insert(0, lhs)) +
        +
        template<class charT, class traits, class Allocator>
   basic_string<charT,traits,Allocator>&&
     operator+(basic_string<charT,traits,Allocator>&& lhs,
               basic_string<charT,traits,Allocator>&& rhs);
-
-
-template<class charT, class traits, class Allocator>
+
        +
        +Returns: std::move(lhs.append(rhs)) [Note: Or equivalently +std::move(rhs.insert(0, lhs)) — end note] +
        +
        template<class charT, class traits, class Allocator>
   basic_string<charT,traits,Allocator>&&
     operator+(const charT* lhs,
               basic_string<charT,traits,Allocator>&& rhs);
-
-template<class charT, class traits, class Allocator>
+
        +
        +Returns: std::move(rhs.insert(0, lhs)). +
        +
        template<class charT, class traits, class Allocator>
   basic_string<charT,traits,Allocator>&&
     operator+(charT lhs, basic_string<charT,traits,Allocator>&& rhs);
-
-template<class charT, class traits, class Allocator>
+
        +
        +Returns: std::move(rhs.insert(0, 1, lhs)). +
        +
        template<class charT, class traits, class Allocator>
   basic_string<charT,traits,Allocator>&&
     operator+(basic_string<charT,traits,Allocator>&& lhs,
               const charT* rhs);
-
-template<class charT, class traits, class Allocator>
+
        +
        +Returns: std::move(lhs.append(rhs)). +
        +
        template<class charT, class traits, class Allocator>
   basic_string<charT,traits,Allocator>&&
     operator+(basic_string<charT,traits,Allocator>&& lhs, charT rhs);
-
        + +
        +Returns: std::move(lhs.append(1, rhs)). +
        + @@ -29424,10 +20120,10 @@ template<class charT, class traits, class Allocator>

        1144. "thread safe" is undefined

        -

        Section: 18.5 [support.start.term] Status: New - Submitter: LWG Opened: 2009-06-16 Last modified: 2009-07-04

        +

        Section: 18.5 [support.start.term] Status: Ready + Submitter: LWG Opened: 2009-06-16 Last modified: 2009-10-20

        View all other issues in [support.start.term].

        -

        View all issues with New status.

        +

        View all issues with Ready status.

        Discussion:

        Addresses UK 187

        @@ -29442,356 +20138,103 @@ anywhere else in the standard. Clarify the meaning of "thread safe".

        - -

        Proposed resolution:

        - - - - - -
        -

        1145. inappropriate headers for atomics

        -

        Section: 29 [atomics] Status: New - Submitter: LWG Opened: 2009-06-16 Last modified: 2009-07-04

        -

        View other active issues in [atomics].

        -

        View all other issues in [atomics].

        -

        View all issues with New status.

        -

        Discussion:

        - -

        Addresses UK 312

        - -

        -The contents of the <stdatomic.h> header are not listed anywhere, -and <cstdatomic> is listed as a C99 header in chapter 17. -If we intend to use these for compatibility with a future C standard, -we should not use them now. -

        - - -

        Proposed resolution:

        -

        -Remove <cstdatomic> from the C99 headers in table 14. -Add a new header <atomic> to the headers in table 13. -Update chapter 29 to remove reference to <stdatomic.h> -and replace the use of <cstdatomic> with <atomic>. -

        [ -If and when WG14 adds atomic operations to C -we can add corresponding headers to table 14 with a TR. -]

        - - - - - - -
        -

        1146. "lockfree" does not say enough

        -

        Section: 29.4 [atomics.lockfree] Status: New - Submitter: Jeffrey Yasskin Opened: 2009-06-16 Last modified: 2009-07-04

        -

        View all issues with New status.

        -

        Discussion:

        - -

        Addresses US 88

        - -

        -The "lockfree" facilities do not tell the programmer enough. -

        - -

        -There are 2 problems here. -First, at least on x86, -it's less important to me whether some integral types are lock free -than what is the largest type I can pass to atomic and have it be lock-free. -For example, if long longs are not lock-free, -ATOMIC_INTEGRAL_LOCK_FREE is probably 1, -but I'd still be interested in knowing whether longs are always lock-free. -Or if long longs at any address are lock-free, -I'd expect ATOMIC_INTEGRAL_LOCK_FREE to be 2, -but I may actually care whether I have access to -the cmpxchg16b instruction. -None of the support here helps with that question. -(There are really 2 related questions here: -what alignment requirements are there for lock-free access; -and what processor is the program actually running on, -as opposed to what it was compiled for?) -

        - -

        -Second, having atomic_is_lock_free only apply to individual objects -is pretty useless -(except, as Lawrence Crowl points out, -for throwing an exception when an object is unexpectedly not lock-free). -I'm likely to want to use its result to decide what algorithm to use, -and that algorithm is probably going to allocate new memory -containing atomic objects and then try to act on them. -If I can't predict the lock-freedom of the new object -by checking the lock-freedom of an existing object, -I may discover after starting the algorithm that I can't continue. -

        - -

        [ -2009-06-16 Jeffrey Yasskin adds: +2009 Santa Cruz: ]

        -To solve the first problem, I think 2 macros would help: -MAX_POSSIBLE_LOCK_FREE_SIZE and MAX_GUARANTEED_LOCK_FREE_SIZE, -which expand to the maximum value of sizeof(T) for which atomic may -(or will, respectively) use lock-free operations. -Lawrence points out that this -"relies heavily on implementations -using word-size compare-swap on sub-word-size types, -which in turn requires address modulation." -He expects that to be the end state anyway, so it doesn't bother him much. +The "thread safe" language has already been change in the WP. It was +changed to "happen before", but the current WP text is still a little +incomplete: "happen before" is binary, but the current WP text only +mentions one thing.

        -

        -To solve the second, -I think one could specify that equally aligned objects of the same type -will return the same value from atomic_is_lock_free(). -I don't know how to specify "equal alignment". -Lawrence suggests an additional function, atomic_is_always_lock_free(). +Move to Ready.

        Proposed resolution:

        - - - - - -
        -

        1147. non-volatile atomic functions

        -

        Section: 29.6 [atomics.types.operations] Status: New - Submitter: Jeffrey Yasskin Opened: 2009-06-16 Last modified: 2009-07-04

        -

        View other active issues in [atomics.types.operations].

        -

        View all other issues in [atomics.types.operations].

        -

        View all issues with New status.

        -

        Discussion:

        - -

        Addresses US 90

        +

        +For the following functions in 18.5 [support.start.term]. +

        +
        
+extern "C" int at_quick_exit(void (*f)(void));
+extern "C++" int at_quick_exit(void (*f)(void));
+

        -The C++0X draft -declares all of the functions dealing with atomics (section 29.6 [atomics.types.operations]) -to take volatile arguments. -Yet it also says (29.4-3), +Edit paragraph 10 as follows. +The intent is +to provide the other half of the happens before relation; +to note indeterminate ordering; +and to clean up some formatting.

        - -
        -

        -[ Note: Many operations are volatile-qualified. -The "volatile as device register" semantics have not changed in the standard. -This qualification means that volatility is preserved -when applying these operations to volatile objects. -It does not mean that operations on non-volatile objects become volatile. -Thus, volatile qualified operations on non-volatile objects -may be merged under some conditions. —end note ] -

        -
        +

        +Effects: +The at_quick_exit() functions +register the function pointed to by f +to be called without arguments when quick_exit is called. +It is unspecified whether a call to at_quick_exit() +that does not happen-before happen before (1.10) +all calls to quick_exit +will succeed. +[Note: +the at_quick_exit() functions +shall not introduce a data race (17.6.4.7). +exitnote +—end note] + +[Note: +The order of registration may be indeterminate +if at_quick_exit was called from more than one thread. +—end note] + +[Note: The at_quick_exit registrations +are distinct from the atexit registrations, +and applications may need to call both registration functions +with the same argument. +—end note] +

        -I was thinking about how to implement this in gcc, -and I believe that we'll want to overload most of the functions -on volatile and non-volatile. -Here's why: +For the following function.

        +
        
+void quick_exit [[noreturn]] (int status)
+

        -To let the compiler take advantage of the permission -to merge non-volatile atomic operations and reorder atomics in certain, -we'll need to tell the compiler backend -about exactly which atomic operation was used. -So I expect most of the functions of the form atomic_<op>_explicit() -(e.g. atomic_load_explicit, atomic_exchange_explicit, -atomic_fetch_add_explicit, etc.) -to become compiler builtins. -A builtin can tell whether its argument was volatile or not, -so those functions don't really need extra explicit overloads. -However, I don't expect that we'll want to add builtins -for every function in chapter 29, -since most can be implemented in terms of the _explicit free functions: +Edit paragraph 13 as follows. +The intent is to note that thread-local variables may be different.

        - -
        class atomic_int {
-  __atomic_int_storage value;
- public:
-  int fetch_add(int increment, memory_order order = memory_order_seq_cst) volatile {
-    // &value has type "volatile __atomic_int_storage*".
-    atomic_fetch_add_explicit(&value, increment, order);
-  }
-  ...
-};
-
        - -

        -But now this always calls -the volatile builtin version of atomic_fetch_add_explicit(), -even if the atomic_int wasn't declared volatile. -To preserve volatility and the compiler's permission to optimize, -I'd need to write: -

        - -
        class atomic_int {
-  __atomic_int_storage value;
- public:
-  int fetch_add(int increment, memory_order order = memory_order_seq_cst) volatile {
-    atomic_fetch_add_explicit(&value, increment, order);
-  }
-  int fetch_add(int increment, memory_order order = memory_order_seq_cst) {
-    atomic_fetch_add_explicit(&value, increment, order);
-  }
-  ...
-};
-
        - -

        -But this is visibly different from the declarations in the standard -because it's now overloaded. -(Consider passing &atomic_int::fetch_add as a template parameter.) -

        - -

        -The implementation may already have permission to add overloads -to the member functions: -

        - -
        -

        -17.6.4.5 [member.functions] An implementation may declare additional non-virtual -member function signatures within a class:
        -... -

        -
          -
        • by adding a member function signature for a member function name.
          • -
        -
        - -

        -but I don't see an equivalent permission to add overloads to the free functions. -

        - -

        [ -2009-06-16 Lawrence adds: -]

        - - -
        -

        -I recommend allowing non-volatile overloads. -

        -
        - - - -

        Proposed resolution:

        - - - - - -
        -

        1148. Wrong argument type of I/O stream manipulators setprecision() -and setw()

        -

        Section: 27.7 [iostream.format] Status: New - Submitter: Marc Steinbach Opened: 2009-06-20 Last modified: 2009-07-30

        -

        View all other issues in [iostream.format].

        -

        View all issues with New status.

        -

        Discussion:

        -

        -The header <iomanip> synopsis in 27.7 [iostream.format] specifies -

        -
        T5 setprecision(int n);
-T6 setw(int n);
-
        - -

        -The argument types should be streamsize, as in class ios_base -(see 27.5.2 [ios.base]): -

        -
        streamsize precision() const;
-streamsize precision(streamsize prec);
-streamsize width() const;
-streamsize width(streamsize wide);
-
        - -

        -(Editorial: 'wide' should probably be renamed as 'width', or maybe just 'w'.) -

        - -

        [ -2009-07-29 Daniel clarified wording. -]

        - - - -

        Proposed resolution:

        -
          -
        1. -

          -In 27.7 [iostream.format], header <iomanip> synopsis change as indicated: -

          - -
          T5 setprecision(intstreamsize n);
-T6 setw(intstreamsize n);
-
          -
          2. - -
        2. -

          -In 27.7.3 [std.manip], just before p. 6 change as indicated: -

          - -
          unspecified setprecision(intstreamsize n);
-
          -
          3. - -
        3. -

          -In 27.7.3 [std.manip], just before p. 7 change as indicated: -

          - -
          unspecified setw(intstreamsize n);
-
          -
          4. -
        - - - - - - - - -
        -

        1150. wchar_t, char16_t and char32_t filenames

        -

        Section: 27.9.1.14 [fstream] Status: New - Submitter: LWG Opened: 2009-06-28 Last modified: 2009-07-04

        -

        View all issues with New status.

        -

        Discussion:

        -

        Addresses JP 73

        - -

        Description

        -

        It is a problem - from C++98, fstream cannot appoint a filename of wide - character string(const wchar_t and const wstring&).

        -

        Suggestion

        -

        Add - interface corresponding to wchar_t, char16_t and char32_t.

        - -

        [ -2009-07-01 Alisdair notes that this is a duplicate of 454 which has more -in-depth rationale. -]

        - - - -

        Proposed resolution:

        +

        +Effects: +Functions registered by calls to at_quick_exit +are called in the reverse order of their registration, +except that a function shall be called +after any previously registered functions +that had already been called at the time it was registered. +Objects shall not be destroyed as a result of calling quick_exit. +If control leaves a registered function called by quick_exit +because the function does not provide a handler for a thrown exception, +terminate() shall be called. + +[Note: +Functions registered by one thread may be called by any thread, +and hence should not rely on the identity of thread-storage-duration objects. +—end note] + +After calling registered functions, +quick_exit shall call _Exit(status). +[Note: +The standard file buffers are not flushed. +See: ISO C 7.20.4.4. +—end note] +

        @@ -29799,11 +20242,11 @@ in-depth rationale.

        1151. Behavior of the library in the presence of threads is incompletely specified

        -

        Section: 17 [library] Status: New - Submitter: LWG Opened: 2009-06-28 Last modified: 2009-06-28

        +

        Section: 17 [library] Status: Open + Submitter: LWG Opened: 2009-06-28 Last modified: 2009-10-20

        View other active issues in [library].

        View all other issues in [library].

        -

        View all issues with New status.

        +

        View all issues with Open status.

        Discussion:

        Addresses US 63

        @@ -29824,6 +20267,18 @@ in-depth rationale.

        Concurrency SG: Create an issue. Hans will look into it.

        +

        [ +2009 Santa Cruz: +]

        + + +
        +Move to "Open". Hans and the rest of the concurrency working group will +study this. We can't make progress without a thorough review and a +paper. +
        + +

        Proposed resolution:

        @@ -29833,11 +20288,11 @@ in-depth rationale.

        1152. expressions parsed differently than intended

        -

        Section: 22.4.2.2.2 [facet.num.put.virtuals] Status: New - Submitter: Seungbeom Kim Opened: 2009-06-27 Last modified: 2009-07-24

        +

        Section: 22.4.2.2.2 [facet.num.put.virtuals] Status: Tentatively Ready + Submitter: Seungbeom Kim Opened: 2009-06-27 Last modified: 2009-10-28

        View other active issues in [facet.num.put.virtuals].

        View all other issues in [facet.num.put.virtuals].

        -

        View all issues with New status.

        +

        View all issues with Tentatively Ready status.

        Discussion:

        In Table 73 -- Floating-point conversions, 22.4.2.2.2 [facet.num.put.virtuals], @@ -29878,14 +20333,24 @@ but technically parsed as: and should be corrected with additional parentheses, as shown above.

        +

        [ +2009-10-28 Howard: +]

        + + +
        +Moved to Tentatively Ready after 5 positive votes on c++std-lib. +
        + +

        Proposed resolution:

        -Change Table 73 — Floating-point conversions in 22.4.2.2.2 [facet.num.put.virtuals]: +Change Table 83 — Floating-point conversions in 22.4.2.2.2 [facet.num.put.virtuals]:

        - + @@ -29907,11 +20372,11 @@ Change Table 73 — Floating-point conversions in 22.4.2.2.2 [facet.num.put

        1153. Standard library needs review for constructors to be explicit to avoid treatment as initializer-list constructor

        -

        Section: 17 [library], 30 [thread], D [depr] Status: New - Submitter: LWG Opened: 2009-06-28 Last modified: 2009-07-04

        +

        Section: 17 [library], 30 [thread], D [depr] Status: Open + Submitter: LWG Opened: 2009-06-28 Last modified: 2009-10-20

        View other active issues in [library].

        View all other issues in [library].

        -

        View all issues with New status.

        +

        View all issues with Open status.

        Discussion:

        Addresses DE 2

        @@ -29932,6 +20397,15 @@ explicit to avoid treatment as initializer-list constructor

        Notes

        Robert Klarer to address this one.

        +

        [ +2009 Santa Cruz: +]

        + + +
        +Move to "Open". Robert Klarer has promised to provide wording. +
        +

        Proposed resolution:

        @@ -29943,7 +20417,7 @@ explicit to avoid treatment as initializer-list constructor

        1154. complex should accept integral types

        Section: 26.4 [complex.numbers] Status: New - Submitter: LWG Opened: 2009-06-28 Last modified: 2009-07-04

        + Submitter: LWG Opened: 2009-06-28 Last modified: 2009-10-26

        View all other issues in [complex.numbers].

        View all issues with New status.

        Discussion:

        @@ -29958,44 +20432,17 @@ explicit to avoid treatment as initializer-list constructor

        Suggestion

        +

        [ +2009-10-26 Proposed wording in +N3002. +]

        -

        Proposed resolution:

        - - - - - -
        -

        1155. Reference should be to C99

        -

        Section: C.2 [diff.library] Status: New - Submitter: LWG Opened: 2009-06-28 Last modified: 2009-07-25

        -

        View other active issues in [diff.library].

        -

        View all other issues in [diff.library].

        -

        View all issues with New status.

        -

        Discussion:

        - -

        Addresses FR 38

        - -

        Description

        -

        What is ISO/IEC 1990:9899/DAM - 1? My guess is that's a typo for ISO/IEC - 9899/Amd.1:1995 which I'd - have expected to be referenced here (the tables - make reference to things - which were introduced by Amd.1).

        -

        Suggestion

        -

        One need probably a reference - to the document which introduce char16_t and - char32_t in C (ISO/IEC TR 19769:2004?).

        -

        Notes

        -

        Create issue. Document in question should be C99, not C90+amendment1. The - rest of the section requires careful review for completeness. Example <cstdint> - 18.4.1 [cstdint.syn]. Assign to C liasons.

        -

        Proposed resolution:

        +Adopt +N3002. @@ -30003,9 +20450,9 @@ explicit to avoid treatment as initializer-list constructor

        1156. Constraints on bitmask and enumeration types to be tightened

        -

        Section: 17.5.2.1.2 [enumerated.types], 17.5.2.1.3 [bitmask.types] Status: New - Submitter: LWG Opened: 2009-06-28 Last modified: 2009-07-25

        -

        View all issues with New status.

        +

        Section: 17.5.2.1.2 [enumerated.types], 17.5.2.1.3 [bitmask.types] Status: Open + Submitter: LWG Opened: 2009-06-28 Last modified: 2009-10-27

        +

        View all issues with Open status.

        Discussion:

        Addresses UK 165

        @@ -30024,6 +20471,16 @@ explicit to avoid treatment as initializer-list constructor

        Notes

        Robert Klarer to review

        +

        [ +2009 Santa Cruz: +]

        + + +
        +Move to Open. Ping Robert Klarer to provide wording, using N2235 as +guidance. +
        +

        Proposed resolution:

        @@ -30034,9 +20491,9 @@ explicit to avoid treatment as initializer-list constructor

        1157. Local types can now instantiate templates

        -

        Section: 17.6.3.2.1 [namespace.std] Status: Review - Submitter: LWG Opened: 2009-06-28 Last modified: 2009-07-28

        -

        View all issues with Review status.

        +

        Section: 17.6.3.2.1 [namespace.std] Status: Ready + Submitter: LWG Opened: 2009-06-28 Last modified: 2009-10-21

        +

        View all issues with Ready status.

        Discussion:

        Addresses UK 175

        @@ -30056,6 +20513,15 @@ explicit to avoid treatment as initializer-list constructor ]

        +

        [ +2009-10 Santa Cruz: +]

        + + +
        +Moved to Ready. +
        +

        Proposed resolution:

        @@ -30110,9 +20576,9 @@ library requirements for the original template.

        1158. Encouragement to use monotonic clock

        -

        Section: 30.2.4 [thread.req.timing] Status: New - Submitter: LWG Opened: 2009-06-28 Last modified: 2009-07-05

        -

        View all issues with New status.

        +

        Section: 30.2.4 [thread.req.timing] Status: Tentatively Ready + Submitter: LWG Opened: 2009-06-28 Last modified: 2009-10-31

        +

        View all issues with Tentatively Ready status.

        Discussion:

        Addresses UK 322, US 96

        @@ -30132,7 +20598,16 @@ library requirements for the original template. meaning clear.

        [ 2009-06-29 Beman provided a proposed resolution. ]

        - + +

        [ +2009-10-31 Howard adds: +]

        + + +
        +Set to Tentatively Ready after 5 positive votes on c++std-lib. +
        +

        Proposed resolution:

        @@ -30209,278 +20684,6 @@ monotonic clock to measure time for these functions.

        -
        -

        1160. future_error public constructor is 'exposition only'

        -

        Section: 30.6.3 [futures.future_error] Status: Open - Submitter: LWG Opened: 2009-06-28 Last modified: 2009-07-17

        -

        View all issues with Open status.

        -

        Discussion:

        - -

        Addresses UK 331

        - -

        Description

        -

        Not clear what - it means for a public constructor to be 'exposition only'. - If the intent is purely to support the library calling this - constructor then it can be made private and accessed - through friendship. Otherwise it should be documented for - public consumption.

        -

        Suggestion

        -

        Declare the constructor as private with a - note about intended friendship, or remove the - exposition-only comment and document the semantics.

        -

        Notes

        -

        Create an issue. Assigned to Detlef. Suggested resolution probably makes - sense.

        - -

        [ -2009-07 Frankfurt -]

        - - -
        -Pending a paper from Anthony Williams / Detleff Volleman. -
        - - - -

        Proposed resolution:

        - - - - - -
        -

        1161. Unnecessary unique_future limitations

        -

        Section: 30.6.5 [futures.unique_future] Status: Open - Submitter: LWG Opened: 2009-06-28 Last modified: 2009-07-17

        -

        View other active issues in [futures.unique_future].

        -

        View all other issues in [futures.unique_future].

        -

        View all issues with Open status.

        -

        Discussion:

        - -

        Addresses UK 336

        - -

        Description

        - -

        It is possible - to transfer ownership of the asynchronous result from one - unique_future instance to another via the move-constructor. - However, it is not possible to transfer it back, and nor is - it possible to create a default-constructed unique_future - instance to use as a later move target. This unduly limits - the use of unique_future in code. Also, the lack of a - move-assignment operator restricts the use of unique_future - in containers such as std::vector - vector::insert requires - move-assignable for example.

        -

        Suggestion

        -

        Add a default constructor with the - semantics that it creates a unique_future with no - associated asynchronous result. Add a move-assignment - operator which transfers ownership.

        -

        Notes

        -

        Create an issue. Detlef will look into it.

        - -

        [ -2009-07 Frankfurt -]

        - - -
        -Pending a paper from Anthony Williams / Detleff Volleman. -
        - - - -

        Proposed resolution:

        - - - - - -
        -

        1162. shared_future should support an efficient move constructor

        -

        Section: 30.6.6 [future.shared_future] Status: Open - Submitter: LWG Opened: 2009-06-28 Last modified: 2009-07-17

        -

        View other active issues in [future.shared_future].

        -

        View all other issues in [future.shared_future].

        -

        View all issues with Open status.

        -

        Discussion:

        - -

        Addresses UK 337

        - -

        Description

        -

        shared_future - should support an efficient move constructor that can avoid - unnecessary manipulation of a reference count, much like - shared_ptr

        -

        Suggestion

        -

        Add a move constructor

        -

        Notes

        -

        Create an issue. Detlef will look into it.

        - -

        [ -2009-07 Frankfurt -]

        - - -
        -Pending a paper from Anthony Williams / Detleff Volleman. -
        - - - -

        Proposed resolution:

        - - - - - -
        -

        1163. shared_future is inconsistent with shared_ptr

        -

        Section: 30.6.6 [future.shared_future] Status: Open - Submitter: LWG Opened: 2009-06-28 Last modified: 2009-07-17

        -

        View other active issues in [future.shared_future].

        -

        View all other issues in [future.shared_future].

        -

        View all issues with Open status.

        -

        Discussion:

        - -

        Addresses UK 338

        - -

        Description

        - -

        shared_future is currently - CopyConstructible, but not CopyAssignable. This is - inconsistent with shared_ptr, and will surprise users. - Users will then write work-arounds to provide this - behaviour. We should provide it simply and efficiently as - part of shared_future. Note that since the shared_future - member functions for accessing the state are all declared - const, the original usage of an immutable shared_future - value that can be freely copied by multiple threads can be - retained by declaring such an instance as "const - shared_future".

        -

        Suggestion

        -

        Remove "=delete" - from the copy-assignment operator of shared_future. Add a - move-constructor shared_future(shared_future&& - rhs), and a move-assignment operator shared_future& - operator=(shared_future&& rhs). The postcondition - for the copy-assignment operator is that *this has the same - associated state as rhs. The postcondition for the - move-constructor and move assignment is that *this has the - same associated as rhs had before the - constructor/assignment call and that rhs has no associated - state.

        -

        Notes

        -

        Create an issue. Detlef will look into it.

        - -

        [ -2009-07 Frankfurt -]

        - - -
        -Pending a paper from Anthony Williams / Detleff Volleman. -
        - - - -

        Proposed resolution:

        - - - - - -
        -

        1165. Unneeded promise move constructor

        -

        Section: 30.6.4 [futures.promise] Status: Open - Submitter: LWG Opened: 2009-06-28 Last modified: 2009-07-17

        -

        View other active issues in [futures.promise].

        -

        View all other issues in [futures.promise].

        -

        View all issues with Open status.

        -

        Discussion:

        - -

        Addresses UK 343

        - -

        Description

        -

        The move constructor of a std::promise - object does not need to allocate any memory, so the - move-construct-with-allocator overload of the constructor - is superfluous.

        -

        Suggestion

        -

        Remove the - constructor with the signature template <class - Allocator> promise(allocator_arg_t, const Allocator& - a, promise& rhs);

        -

        Notes

        -

        Create an issue. Detlef will look into it. Will solicit feedback from Pablo. - Note that “rhs” argument should also be an rvalue reference in any case.

        - -

        [ -2009-07 Frankfurt -]

        - - -
        -Pending a paper from Anthony Williams / Detleff Volleman. -
        - - - -

        Proposed resolution:

        - - - - - -
        -

        1166. Allocator-specific move/copy break model of move-constructor and - move-assignment

        -

        Section: X [allocator.propagation], X [allocator.propagation.map], 23 [containers] Status: New - Submitter: LWG Opened: 2009-06-28 Last modified: 2009-07-04

        -

        View all issues with New status.

        -

        Discussion:

        - -

        Addresses US 77

        - -

        Description

        -

        Allocator-specific move and copy behavior for containers - (N2525) complicates a little-used and already-complicated - portion of the standard library (allocators), and breaks - the conceptual model of move-constructor and - move-assignment operations on standard containers being - efficient operations. The extensions for allocator-specific - move and copy behavior should be removed from the working - paper.

        -

        With the - introduction of rvalue references, we are teaching - programmers that moving from a standard container (e.g., a - vector<string>) is an efficient, constant-time - operation. The introduction of N2525 removed that - guarantee; depending on the behavior of four different - traits (20.8.4), the complexity of copy and move operations - can be constant or linear time. This level of customization - greatly increases the complexity of standard containers, - and benefits only a tiny fraction of the C++ community.

        -

        Suggestion

        - -

        Remove 20.8.4.

        - -

        Remove 20.8.5.

        - -

        Remove all references to the facilities in - 20.8.4 and 20.8.5 from clause 23.

        - - - - -

        Proposed resolution:

        - - - - -

        1169. num_get not fully compatible with strto*

        Section: 22.4.2.1.2 [facet.num.get.virtuals] Status: New @@ -30596,10 +20799,12 @@ field represents a value outside the range of representable values,

        1170. String char-like types no longer PODs

        Section: 21.1 [strings.general] Status: New - Submitter: Beman Dawes Opened: 2009-06-22 Last modified: 2009-07-28

        + Submitter: Beman Dawes Opened: 2009-06-22 Last modified: 2009-11-04

        View all issues with New status.

        Discussion:

        +

        Addresses UK 218

        +

        Prior to the introduction of constant expressions into the library, basic_string elements had to be POD types, and thus had to be both trivially copyable and standard-layout. This ensured that they could be memcpy'ed and @@ -30646,16 +20851,23 @@ believe the current wording offers the right guarantees for either of the above designs. +

        [ +2009-11-04 Howard modifies proposed wording to disallow array types as +char-like types. +]

        + +

        Proposed resolution:

        Change General 21.1 [strings.general] as indicated:

        -

        This Clause describes components for manipulating sequences of any literal POD -(3.9) type. In this Clause -such types are called char-like types, and objects of char-like types are -called char-like objects or simply characters.

        +

        This Clause describes components for manipulating sequences of any +literal non-array POD (3.9) type. In this Clause +such types are called char-like types, and objects of char-like +types are called char-like objects or simply +characters.

        @@ -30664,12 +20876,12 @@ called char-like objects or simply characters.

        -

        1171. duration types shoud be literal

        -

        Section: 20.9.3 [time.duration] Status: New - Submitter: Alisdair Meredith Opened: 2009-07-06 Last modified: 2009-07-07

        +

        1171. duration types should be literal

        +

        Section: 20.9.3 [time.duration] Status: Open + Submitter: Alisdair Meredith Opened: 2009-07-06 Last modified: 2009-10-31

        View other active issues in [time.duration].

        View all other issues in [time.duration].

        -

        View all issues with New status.

        +

        View all issues with Open status.

        Discussion:

        The duration types in 20.9.3 [time.duration] are exactly the sort of type @@ -30677,6 +20889,42 @@ that should be "literal types" in the new standard. Likewise, arithmetic operations on durations should be declared constexpr.

        +

        [ +2009-09-21 Daniel adds: +]

        + + +
        +An alternative (and possibly preferable solution for potentially +heap-allocating big_int representation types) would be to ask the core +language to allow references to const literal types as feasible +arguments for constexpr functions. +
        + +

        [ +2009-10-30 Alisdair adds: +]

        + + +
        +

        +I suggest this issue moves from New to Open. +

        + +

        +Half of this issue was dealt with in paper +n2994 +on constexpr constructors. +

        + +

        +The other half (duration arithmetic) is on hold pending Core support for +const & in constexpr functions. +

        + +
        + +

        Proposed resolution:

        @@ -30772,85 +21020,13 @@ They cannot meaningfully be constexpr without this change. -

        -

        1172. select_on_container_(copy|move)_construction over-constrained

        -

        Section: 20.8.2.4 [allocator.concepts.members] Status: New - Submitter: Alberto Ganesh Barbati Opened: 2009-07-08 Last modified: 2009-07-14

        -

        View all issues with New status.

        -

        Discussion:

        -

        -I believe the two functions -select_on_container_(copy|move)_construction() are over-constrained. For -example, the return value of the "copy" version is (see -20.8.2.4 [allocator.concepts.members]/21): -

        -
        -Returns: x if the allocator should propagate from the existing -container to the new container on copy construction, otherwise X(). -
        -

        -Consider the case where a user decides to provide an explicit concept -map for Allocator to adapt some legacy allocator class, as he wishes to -provide customizations that the LegacyAllocator concept map template -does not provide. Now, although it's true that the legacy class is -required to have a default constructor, the user might have reasons to -prefer a different constructor to implement -select_on_container_copy_construction(). However, the current wording -requires the use of the default constructor. -

        -

        -Moreover, it's not said explicitly that x is supposed to be the -allocator of the existing container. A clarification would do no harm. -

        - - -

        Proposed resolution:

        -

        -Replace 20.8.2.4 [allocator.concepts.members]/21 with: -

        - -
        X select_on_container_copy_construction(const X& x);
-
        -

        --21- Returns: x if the allocator should propagate from the existing -container to the new container on copy construction, otherwise X(). -an allocator object to be used by the new container on copy -construction. [Note: x is the allocator of the existing container that -is being copied. The most obvious choices for the return value are x, if -the allocator should propagate from the existing container, and X(). -— end note] -

        -
        - -

        -Replace 20.8.2.4 [allocator.concepts.members]/25 with: -

        - -
        X select_on_container_move_construction(X&& x);
-
        -

        --25- Returns: move(x) if the allocator should propagate from the existing -container to the new container on move construction, otherwise X(). -an allocator object to be used by the new container on move -construction. [Note: x is the allocator of the existing container that -is being moved. The most obvious choices for the return value are move(x), if -the allocator should propagate from the existing container, and X(). -— end note] -

        -
        - - - - - -

        1173. "Equivalence" wishy-washiness

        -

        Section: 17 [library] Status: New - Submitter: David Abrahams Opened: 2009-07-14 Last modified: 2009-07-14

        +

        Section: 17 [library] Status: Open + Submitter: David Abrahams Opened: 2009-07-14 Last modified: 2009-10-20

        View other active issues in [library].

        View all other issues in [library].

        -

        View all issues with New status.

        +

        View all issues with Open status.

        Discussion:

        Issue: The CopyConstructible requirements are wishy-washy. It requires @@ -30874,53 +21050,21 @@ require the elements to be EqualityComparable, so that table is actuall referring to some ill-defined notion of equivalence when it uses ==.

        - -

        Proposed resolution:

        - - - - - -
        -

        1174. type property predicates

        -

        Section: 20.6.4.3 [meta.unary.prop] Status: New - Submitter: Jason Merrill Opened: 2009-07-16 Last modified: 2009-07-17

        -

        View other active issues in [meta.unary.prop].

        -

        View all other issues in [meta.unary.prop].

        -

        View all issues with New status.

        -

        Discussion:

        -

        -I've been implementing compiler support for is_standard_layout, and -noticed a few nits about 20.6.4.3 [meta.unary.prop]: -

        - -
          -
        1. -There's no trait for "trivially copyable type", which is now the -property that lets you do bitwise copying of a type, and therefore seems -useful to be able to query. has_trivial_assign && -has_trivial_copy_constructor && has_trivial_destructor -is similar, but -not identical, specifically with respect to const types. -
          2. -
        2. -has_trivial_copy_constructor and has_trivial_assign lack the "or an -array of such a class type" language that most other traits in that -section, including has_nothrow_copy_constructor and has_nothrow_assign, -have; this seems like an oversight. -
          3. -
        -

        [ -See the thread starting with c++std-lib-24420 for further discussion. +2009 Santa Cruz: ]

        +
        +Move to "Open". Dave is right that this is a big issue. Paper D2987 +("Defining Move Special Member Functions", Bjarne Stroustrup and +Lawrence Crowl) touches on this but does not solve it. This issue is +discussed in Elements of Programming. +
        +

        Proposed resolution:

        -

        -

        @@ -30999,11 +21143,11 @@ with "decay behavior", but using variadics.

        1177. Improve "diagnostic required" wording

        -

        Section: 20.9.3 [time.duration] Status: New - Submitter: Howard Hinnant Opened: 2009-07-18 Last modified: 2009-08-01

        +

        Section: 20.9.3 [time.duration] Status: Ready + Submitter: Howard Hinnant Opened: 2009-07-18 Last modified: 2009-10-26

        View other active issues in [time.duration].

        View all other issues in [time.duration].

        -

        View all issues with New status.

        +

        View all issues with Ready status.

        Discussion:

        "diagnostic required" has been used (by me) for code words meaning "use @@ -31012,14 +21156,25 @@ improved by referring to the function signature as not participating in the overload set, and moving this wording to a Remarks paragraph.

        +

        [ +2009-10 Santa Cruz: +]

        + + +
        +Moved to Ready. +
        +

        Proposed resolution:

        [ -This proposed resolution addresses 947 and 974. +This proposed resolution addresses 947 and 974. ]

        +
          +

        1. Change 20.9.3.1 [time.duration.cons]:

          @@ -31087,7 +21242,7 @@ duration<int, milli> ms2 = us; // error

          -Eff�ects: Constructs an object of type duration, constructing +Effects: Constructs an object of type duration, constructing rep_ from duration_cast<duration>(d).count().

          @@ -31096,7 +21251,9 @@ duration<int, milli> ms2 = us; // error +
          2. +

        2. Change the following paragraphs in 20.9.3.5 [time.duration.nonmember]:

          @@ -31145,129 +21302,43 @@ overload resolution. Diagnostic required. +
          3. - - - - - -
          -

          1178. Header dependencies

          -

          Section: 17.6.4.2 [res.on.headers] Status: Ready - Submitter: Beman Dawes Opened: 2009-07-18 Last modified: 2009-07-18

          -

          View all issues with Ready status.

          -

          Discussion:

          +

        3. -See Frankfurt notes of 1001. +Change the following paragraphs in 20.9.3.7 [time.duration.cast]:

          - -

          Proposed resolution:

          -

          Change 17.6.4.2 [res.on.headers], Headers, paragraph 1, as indicated:

          +
          template <class ToDuration, class Rep, class Period> 
+  ToDuration duration_cast(const duration<Rep, Period>& d);
+
          - -

          -A C++ header may include other C++ -headers.[footnote] A C++ header shall provide -the declarations and definitions that appear in its synopsis -(3.2 [basic.def.odr]). A C++ header shown in its synopsis as including -other C++ headers shall provide the declarations and definitions that appear in -the synopses of those other headers. -

          - -

          [footnote] C++ headers must include a C++ header that contains - any needed definition (3.2).

          +Requires Remarks: ToDuration shall be an instantiation of +duration, else this signature shall not participate in +overload resolution. Diagnostic required.
          +
          +
          4. - - - - - -
          -

          1179. Probably editorial in [structure.specifications]

          -

          Section: 17.5.1.4 [structure.specifications] Status: New - Submitter: Robert Klarer Opened: 2009-07-21 Last modified: 2009-07-22

          -

          View all other issues in [structure.specifications].

          -

          View all issues with New status.

          -

          Discussion:

          +

        4. -While reviewing 971 I noted that 17.5.1.4 [structure.specifications]/7 says: +Change the following paragraphs in 20.9.4.7 [time.point.cast]:

          +
          template <class ToDuration, class Clock, class Duration> 
+  time_point<Clock, ToDuration> time_point_cast(const time_point<Clock, Duration>& t);
+
          +
          --7- Error conditions specify conditions where a function may fail. The -conditions are listed, together with a suitable explanation, as the enum -class errc constants (19.5) that could be used as an argument to -function make_error_condition (19.5.3.6). +Requires Remarks: ToDuration shall be an instantiation of +duration, else this signature shall not participate in +overload resolution. Diagnostic required.
          - -

          -This paragraph should mention make_error_code or the text "that -could be used as an argument to function make_error_condition -(19.5.3.6)" should be deleted. I believe this is editorial. -

          - -

          [ -2009-07-21 Chris adds: -]

          - - -
          -

          -I'm not convinced there's a problem there, because as far as the "Error -conditions" clauses are concerned, make_error_condition() is used by a -user to test for the condition, whereas make_error_code is not. For -example: -

          - -
          void foobar(error_code& ec = throws());
-
          - -

          - Error conditions: -

          -
          -permission_denied - Insufficient privilege to perform operation.
          +
          5. +
        -

        -When a user writes: -

        - -
        error_code ec;
-foobar(ec);
-if (ec == errc::permission_denied)
-   ...
-
        - -

        -the implicit conversion errc->error_condition makes the if-test -equivalent to: -

        - -
        if (ec == make_error_condition(errc::permission_denied))
-
        - -

        -On the other hand, if the user had written: -

        - -
        if (ec == make_error_code(errc::permission_denied))
-
        - -

        -the test is now checking for a specific error code. The test may -evaluate to false even though foobar() failed due to the documented -error condition "Insufficient privilege". -

        - - - -

        Proposed resolution:

        -

        -

        @@ -31744,8 +21815,8 @@ sub_match<BiIter>::value_type>(rhs.begin(), rhs.end()).

        1182. Unfortunate hash dependencies

        -

        Section: 20.7.17 [unord.hash] Status: New - Submitter: Alisdair Meredith Opened: 2009-07-28 Last modified: 2009-07-30

        +

        Section: 20.7.16 [unord.hash] Status: New + Submitter: Alisdair Meredith Opened: 2009-07-28 Last modified: 2009-09-21

        View other active issues in [unord.hash].

        View all other issues in [unord.hash].

        View all issues with New status.

        @@ -31764,9 +21835,111 @@ template in order to access the necessary bits.

        Note that the proposed resolution purely involves moving the declarations of a few specializations, it specifically does not make any -changes to 20.7.17 [unord.hash]. +changes to 20.7.16 [unord.hash].

        +

        [ +2009-09-15 Daniel adds: +]

        + + +
        +
        +

        +I suggest to add to the current existing +proposed resolution the following items. +

        + +
          +
        • +

          +Add to the very first strike-list of the currently suggested resolution +the following lines: +

          + +
          template <> struct hash<std::error_code>;
+template <> struct hash<std::thread::id>;
+
          +
          • + +
        • +

          +Add the following declarations to 19.5 [syserr], header +<system_error> synopsis after // 19.5.4: +

          + +
          
+// 19.5.x hash support
+template <class T> struct hash;
+template <> struct hash<error_code>;
+
+
          +
          • + +
        • +

          +Add a new clause 19.5.X (probably after 19.5.4): +

          + +
          +

          +19.5.X Hash support [syserr.hash] +

          + +
          
+template <> struct hash<error_code>;
+
          + +
          +An explicit specialization of the class template hash (20.7.16 [unord.hash]) +shall be provided +for the type error_code suitable for using this type as key in +unordered associative +containers (23.5 [unord]). +
          +
          +
          • + +
        • +

          +Add the following declarations to 30.3.1.1 [thread.thread.id] just after the +declaration of +the comparison operators: +

          + +
          
+template <class T> struct hash;
+template <> struct hash<thread::id>;
+
          +
          • + +
        • +

          +Add a new paragraph at the end of 30.3.1.1 [thread.thread.id]: +

          + +
          +
          
+template <> struct hash<thread::id>;
+
          + +
          +An explicit specialization of the class template hash (20.7.16 [unord.hash]) +shall be provided +for the type thread::id suitable for using this type as key in +unordered associative +containers (23.5 [unord]). +
          +
          +
          • + +
        • +Issue 889 independently suggests moving the specialization +std::hash<std::thread::id> to header <thread>. +
          • +
        + +

        Proposed resolution:

        @@ -31812,7 +21985,7 @@ template <> struct hash<wstring>;

        -Explicit specializations of the class template hash (20.7.17 [unord.hash]) +Explicit specializations of the class template hash (20.7.16 [unord.hash]) shall be provided for the types string, u16string, u32string and wstring suitable for using these types as keys in unordered associative containers (23.5 [unord]). @@ -31837,7 +22010,7 @@ Add a new paragraph to the end of 23.3.7 [vector.bool] 
        template <class Allocator> struct hash<vector<bool, Allocator>>;
        -A partial specialization of the class template hash (20.7.17 [unord.hash]) +A partial specialization of the class template hash (20.7.16 [unord.hash]) shall be provided for vectors of boolean values suitable for use as a key in unordered associative containers (23.5 [unord]).
        @@ -31845,7 +22018,7 @@ in unordered associative containers (23.5 [unord]).

        Add the following declarations to the synopsis of <bitset> -in 20.3.6 [template.bitset] +in 20.3.7 [template.bitset] 

        
@@ -31868,7 +22041,7 @@ Add a new subclause 20.3.6.X [bitset.hash]
 
 
        
 A partial specialization of the class template hash
-(20.7.17 [unord.hash]) shall be provided for bitsets suitable for use as a key in
+(20.7.16 [unord.hash]) shall be provided for bitsets suitable for use as a key in
 unordered associative containers (23.5 [unord]).
        @@ -31880,11 +22053,11 @@ unordered associative containers (23.5 [unord]).

        1183. basic_ios::set_rdbuf may break class invariants

        -

        Section: 27.5.4.2 [basic.ios.members] Status: New - Submitter: Daniel Krügler Opened: 2009-07-28 Last modified: 2009-07-28

        +

        Section: 27.5.4.2 [basic.ios.members] Status: Open + Submitter: Daniel Krügler Opened: 2009-07-28 Last modified: 2009-10-22

        View other active issues in [basic.ios.members].

        View all other issues in [basic.ios.members].

        -

        View all issues with New status.

        +

        View all issues with Open status.

        Discussion:

        The protected member function set_rdbuf had been added during the @@ -31926,31 +22099,51 @@ I therefore suggest that a requirement is added for callers of set_rdbuf +

        [ +2009-10 Santa Cruz: +]

        + + +
        +Moved to Open. Martin volunteers to provide new wording, where +set_rdbuf() sets the badbit but does not cause an +exception to be thrown like a call to clear() would. +
        + +

        [ +2009-10-20 Martin provides wording: +]

        + + +

        Proposed resolution:

        -Change 27.5.4.2 [basic.ios.members] around p. 19 as indicated (The proposed -resolution fixes also two editorial problems: Some wrong letters in "clear()" -and moving the post conditions into a separate paragraph): +Change 27.5.4.2 [basic.ios.members] around p. 19 as indicated: 

        void set_rdbuf(basic_streambuf<charT, traits>* sb);
        -

        -Requires: sb != nullptr. -

        +

        +Effects: Associates the basic_streambuf object pointed +to by sb with this stream without calling clear(). +Postconditions: rdbuf() == sb. +

        -

        -Effects: Associates the basic_streambuf object pointed to by sb with -this stream without -calling clear(). Postconditions: rdbuf() == sb. -

        +

        +Effects: As if: +

        -

        -Postconditions: rdbuf() == sb. -

        +
        
+iostate state = rdstate();
+try { rdbuf(sb); }
+catch(ios_base::failure) {
+   if (0 == (state & ios_base::badbit))
+       unsetf(badbit);
+}
+

        Throws: Nothing. @@ -31960,24 +22153,13 @@ calling clear(). Postconditions: rdbuf() == sb.

        - - - -
        -

        1184. Feature request: dynamic bitset

        -

        Section: 23.3.6 [vector] Status: New - Submitter: Alisdair Meredith Opened: 2009-07-29 Last modified: 2009-07-29

        -

        View other active issues in [vector].

        -

        View all other issues in [vector].

        -

        View all issues with New status.

        -

        Discussion:

        -

        -Opened at Alisdair's request, steming from 96. -Alisdair recommends NAD Future. -

        - - -

        Proposed resolution:

        +

        Rationale:

        +We need to be able to call set_rdbuf() on stream objects +for which (rdbuf() == 0) holds without causing ios_base::failure to +be thrown. We also don't want badbit to be set as a result of +setting rdbuf() to 0 if it wasn't set before the call. This changed +Effects clause maintains the current behavior (as of N2914) without +requiring that sb be non-null. @@ -31985,8 +22167,10 @@ Alisdair recommends NAD Future.

        1185. iterator categories and output iterators

        -

        Section: X [iterator.requirements] Status: New +

        Section: 24.2 [iterator.requirements] Status: New Submitter: Alisdair Meredith Opened: 2009-07-31 Last modified: 2009-07-31

        +

        View other active issues in [iterator.requirements].

        +

        View all other issues in [iterator.requirements].

        View all issues with New status.

        Discussion:

        @@ -31996,7 +22180,7 @@ pending new working paper)

        -According to p3 X [iterator.requirements], Forward iterators, +According to p3 24.2 [iterator.requirements], Forward iterators, Bidirectional iterators and Random Access iterators all satisfy the requirements for an Output iterator:

        @@ -32043,9 +22227,8 @@ requires clauses for the appropriate algorithms and operations.

        1186. Forward list could model a stack

        -

        Section: 23.3.5.3 [stack] Status: New - Submitter: Alisdair Meredith Opened: 2009-07-31 Last modified: 2009-08-01

        -

        View all issues with New status.

        +

        Section: 23.3.5.3 [stack] Status: Tentatively NAD Concepts + Submitter: Alisdair Meredith Opened: 2009-07-31 Last modified: 2009-11-02

        Discussion:

        The library template forward_list could easily model the idea of a @@ -32071,6 +22254,15 @@ not so compelling it must be supported ahead of the concepts-based library.

        +

        [ +2009-11-02 Howard adds: +]

        + + +
        +Moved to Tentatively NAD Concepts after 5 positive votes on c++std-lib. +
        +

        Proposed resolution:

        @@ -32078,4 +22270,6005 @@ library. +
        +

        1187. std::decay

        +

        Section: 20.6.7 [meta.trans.other] Status: New + Submitter: Jason Merrill Opened: 2009-08-07 Last modified: 2009-08-22

        +

        View all other issues in [meta.trans.other].

        +

        View all issues with New status.

        +

        Discussion:

        +

        +I notice that std::decay is specified to strip the cv-quals from +anything but an array or pointer. This seems incorrect for values of +class type, since class rvalues can have cv-qualified type (3.10 [basic.lval]/9). +

        + +

        [ +2009-08-09 Howard adds: +]

        + + +
        +See the thread starting with c++std-lib-24568 for further discussion. And +here is a convenience link to the +original proposal. +Also see the closely related issue 705. +
        + + +

        Proposed resolution:

        + +

        +Add a note to decay in 20.6.7 [meta.trans.other]: +

        + +
        +[Note: This behavior is similar to the lvalue-to-rvalue (4.1), +array-to-pointer (4.2), and function-to-pointer (4.3) conversions +applied when an lvalue expression is used as an rvalue, but also strips +cv-qualifiers from class types in order to more closely model by-value +argument passing. — end note] +
        + + + + + + + + +
        +

        1188. Unordered containers should have a minimum load factor as well as a maximum

        +

        Section: 23.2.5 [unord.req], 23.5 [unord] Status: New + Submitter: Matt Austern Opened: 2009-08-10 Last modified: 2009-08-11

        +

        View other active issues in [unord.req].

        +

        View all other issues in [unord.req].

        +

        View all issues with New status.

        +

        Discussion:

        +

        +Unordered associative containers have a notion of a maximum load factor: +when the number of elements grows large enough, the containers +automatically perform a rehash so that the number of elements per bucket +stays below a user-specified bound. This ensures that the hash table's +performance characteristics don't change dramatically as the size +increases. +

        + +

        +For similar reasons, Google has found it useful to specify a minimum +load factor: when the number of elements shrinks by a large enough, the +containers automatically perform a rehash so that the number of elements +per bucket stays above a user-specified bound. This is useful for two +reasons. First, it prevents wasting a lot of memory when an unordered +associative container grows temporarily. Second, it prevents amortized +iteration time from being arbitrarily large; consider the case of a hash +table with a billion buckets and only one element. (This was discussed +even before TR1 was published; it was TR issue 6.13, which the LWG +closed as NAD on the grounds that it was a known design feature. +However, the LWG did not consider the approach of a minimum load +factor.) +

        + +

        +The only interesting question is when shrinking is allowed. In principle +the cleanest solution would be shrinking on erase, just as we grow on +insert. However, that would be a usability problem; it would break a +number of common idioms involving erase. Instead, Google's hash tables +only shrink on insert and rehash. +

        + +

        +The proposed resolution allows, but does not require, shrinking in +rehash, mostly because a postcondition for rehash that involves the +minimum load factor would be fairly complicated. (It would probably have +to involve a number of special cases and it would probably have to +mention yet another parameter, a minimum bucket count.) +

        + +

        +The current behavior is equivalent to a minimum load factor of 0. If we +specify that 0 is the default, this change will have no impact on +backward compatibility. +

        + + +

        Proposed resolution:

        +

        +Add two new rows, and change rehash's postcondition in the unordered +associative container requirements table in 23.2.5 [unord.req]: +

        + +
        +
        Table 73 — Floating-point conversionsTable 83 — Floating-point conversions
        State stdio equivalent
        + + + + + + + + + + + + + + + + + + + + + + + + + +
        Table 87 — Unordered associative container requirements +(in addition to container)
        ExpressionReturn typeAssertion/note pre-/post-conditionComplexity
        +a.min_load_factor() + +float + +Returns a non-negative number that the container attempts to keep the +load factor greater than or equal to. The container automatically +decreases the number of buckets as necessary to keep the load factor +above this number. + +constant +
        a.min_load_factor(z)voidPre: z shall be non-negative. Changes the container's minimum +load factor, using z as a hint. [Footnote: the minimum +load factor should be significantly smaller than the maximum. +If z is too large, the implementation may reduce it to a more sensible value.] + +constant +
        a.rehash(n)void +Post: a.bucket_count() >= n, and a.size() <= a.bucket_count() +* a.max_load_factor(). [Footnote: It is intentional that the +postcondition does not mention the minimum load factor. +This member function is primarily intended for cases where the user knows +that the container's size will increase soon, in which case the container's +load factor will temporarily fall below a.min_load_factor().] + +a.bucket_cout > a.size() / a.max_load_factor() and a.bucket_count() +>= n. + + +Average case linear in a.size(), worst case quadratic. +
        + + +

        +Add a footnote to 23.2.5 [unord.req] p12: +

        + +
        +

        +The insert members shall not affect the validity of references to +container elements, but may invalidate all iterators to the container. +The erase members shall invalidate only iterators and references to the +erased elements. +

        + +
        +[A consequence of these requirements is that while insert may change the +number of buckets, erase may not. The number of buckets may be reduced +on calls to insert or rehash.] +
        +
        + +

        +Change paragraph 13: +

        + +
        +The insert members shall not affect the validity of iterators if +(N+n) < z * B zmin * B <= (N+n) <= zmax * B, +where N is the number of elements in +the container prior to the insert operation, n is the number of +elements inserted, B is the container's bucket count, +zmin is the container's minimum load factor, +and zmax is the container's maximum load factor. +
        + +

        +Add to the unordered_map class synopsis in section 23.5.1 [unord.map], +the unordered_multimap class synopsis +in 23.5.2 [unord.multimap], the unordered_set class synopsis in +23.5.3 [unord.set], and the unordered_multiset class synopsis +in 23.5.4 [unord.multiset]: +

        + +
        
+float min_load_factor() const;
+void min_load_factor(float z);
+
        + +

        +In 23.5.1.1 [unord.map.cnstr], 23.5.2.1 [unord.multimap.cnstr], 23.5.3.1 [unord.set.cnstr], and +23.5.4.1 [unord.multiset.cnstr], change: +

        + +
        +... max_load_factor() returns 1.0 and +min_load_factor() returns 0. +
        + + + + + +
        +

        1189. Awkward interface for changing the number of buckets in an unordered associative container

        +

        Section: 23.2.5 [unord.req], 23.5 [unord] Status: Tentatively Ready + Submitter: Matt Austern Opened: 2009-08-10 Last modified: 2009-10-28

        +

        View other active issues in [unord.req].

        +

        View all other issues in [unord.req].

        +

        View all issues with Tentatively Ready status.

        +

        Discussion:

        +

        +Consider a typical use case: I create an unordered_map and then start +adding elements to it one at a time. I know that it will eventually need +to store a few million elements, so, for performance reasons, I would +like to reserve enough capacity that none of the calls to insert will +trigger a rehash. +

        + +

        +Unfortunately, the existing interface makes this awkward. The user +naturally sees the problem in terms of the number of elements, but the +interface presents it as buckets. If m is the map and n is the expected +number of elements, this operation is written m.rehash(n / +m.max_load_factor()) — not very novice friendly. +

        + +

        [ +2009-09-30 Daniel adds: +]

        + + +
        +I recommend to replace "resize" by a different name like +"reserve", because that would better match the intended +use-case. Rational: Any existing resize function has the on-success +post-condition that the provided size is equal to size(), which +is not satisfied for the proposal. Reserve seems to fit the purpose of +the actual renaming suggestion. +
        + +

        [ +2009-10-28 Ganesh summarizes alternative resolutions and expresses a +strong preference for the second (and opposition to the first): +]

        + + +
        +
          +
        1. +

          +In the unordered associative container requirements (23.2.5 [unord.req]), +remove the row for +rehash and replace it with: +

          + +
          + + + + + + + + + + + + + +
          Table 87 — Unordered associative container requirements +(in addition to container)
          ExpressionReturn typeAssertion/note pre-/post-conditionComplexity
          a.rehashreserve(n)void +Post: a.bucket_count > max(a.size(), n) +/ a.max_load_factor() and a.bucket_count() +>= n. + +Average case linear in a.size(), worst case quadratic. +
          +
          + +

          +Make the corresponding change in the class synopses in 23.5.1 +[unord.map], 23.5.2 [unord.multimap], 23.5.3 [unord.set], and 23.5.4 +[unord.multiset]. +

          +
          2. +
        2. + +

          +In 23.2.5 [unord.req]/9, table 98, append a new row after the last one: +

          + +
          + + + + + + + + + + + + + + + + + + + +
          Table 87 — Unordered associative container requirements +(in addition to container)
          ExpressionReturn typeAssertion/note pre-/post-conditionComplexity
          a.rehash(n)void +Post: a.bucket_count > a.size() +/ a.max_load_factor() and a.bucket_count() +>= n. + +Average case linear in a.size(), worst case quadratic. +
          +a.reserve(n) + +void + +Same as a.rehash(ceil(n / a.max_load_factor())) + +Average case linear in a.size(), worst case quadratic. +
          +
          + +

          +In 23.5.1 [unord.map]/3 in the definition of class template unordered_map, in +23.5.2 [unord.multimap]/3 in the definition of class template unordered_multimap, in +23.5.3 [unord.set]/3 in the definition of class template unordered_set and in +23.5.4 [unord.multiset]/3 in the definition of class template unordered_multiset, add the +following line after member function rehash(): +

          + +
          void reserve(size_type n);
+
          + +
          3. +
        +
        + +

        [ +2009-10-28 Howard: +]

        + + +
        +

        +Moved to Tentatively Ready after 5 votes in favor of Ganesh's option 2 above. +The original proposed wording now appears here: +

        + +
        +

        +Informally: instead of providing rehash(n) provide resize(n), with the +semantics "make the container a good size for n elements". +

        + +

        +In the unordered associative container requirements (23.2.5 [unord.req]), +remove the row for +rehash and replace it with: +

        + +
        + + + + + + + + + + + + + +
        Table 87 — Unordered associative container requirements +(in addition to container)
        ExpressionReturn typeAssertion/note pre-/post-conditionComplexity
        a.rehashresize(n)void +Post: a.bucket_count > max(a.size(), n) +/ a.max_load_factor() and a.bucket_count() +>= n. + +Average case linear in a.size(), worst case quadratic. +
        +
        + +

        Make the corresponding change in the class synopses in 23.5.1 +[unord.map], 23.5.2 [unord.multimap], 23.5.3 [unord.set], and 23.5.4 +[unord.multiset]. +

        + +
        +
        + + +

        Proposed resolution:

        +

        +In 23.2.5 [unord.req]/9, table 98, append a new row after the last one: +

        + +
        + + + + + + + + + + + + + + + + + + + +
        Table 87 — Unordered associative container requirements +(in addition to container)
        ExpressionReturn typeAssertion/note pre-/post-conditionComplexity
        a.rehash(n)void +Post: a.bucket_count > a.size() +/ a.max_load_factor() and a.bucket_count() +>= n. + +Average case linear in a.size(), worst case quadratic. +
        +a.reserve(n) + +void + +Same as a.rehash(ceil(n / a.max_load_factor())) + +Average case linear in a.size(), worst case quadratic. +
        +
        + +

        +In 23.5.1 [unord.map]/3 in the definition of class template unordered_map, in +23.5.2 [unord.multimap]/3 in the definition of class template unordered_multimap, in +23.5.3 [unord.set]/3 in the definition of class template unordered_set and in +23.5.4 [unord.multiset]/3 in the definition of class template unordered_multiset, add the +following line after member function rehash(): +

        + +
        void reserve(size_type n);
+
        + + + + + +
        +

        1190. Setting the maximum load factor should return the previous value

        +

        Section: 23.2.5 [unord.req], 23.5 [unord] Status: New + Submitter: Matt Austern Opened: 2009-08-10 Last modified: 2009-08-11

        +

        View other active issues in [unord.req].

        +

        View all other issues in [unord.req].

        +

        View all issues with New status.

        +

        Discussion:

        +

        +The unordered associative container requirements table specifies that +a.set_max_load_factor(z) has return type void. However, there is a +useful piece of information to return: the previous value. Users who +don't need it can always ignore it. +

        + + +

        Proposed resolution:

        +

        +In the unordered associative container requirements table, change: +

        + +
        + + + + + + + + + + + + + + + +
        Table 87 — Unordered associative container requirements +(in addition to container)
        ExpressionReturn typeAssertion/note pre-/post-conditionComplexity
        a.max_load_factor(z)void floatPre: z shall be positive. Changes the container's maximum +load load factor, using z as a hint. +Returns: the previous value of +a.max_load_factor(). + +constant +
        +
        + +

        +Change the return type of set_max_load_factor +in the class synopses in 23.5.1 [unord.map], 23.5.2 [unord.multimap], 23.5.3 [unord.set], +and 23.5.4 [unord.multiset]. +

        + +

        +If issue 1188 is also accepted, make the same changes for +min_load_factor. +

        + + + + + +
        +

        1191. tuple get API should respect rvalues

        +

        Section: 20.5.2.6 [tuple.elem] Status: Open + Submitter: Alisdair Meredith Opened: 2009-08-18 Last modified: 2009-10-31

        +

        View all issues with Open status.

        +

        Discussion:

        +

        +The tuple get API should respect rvalues. This would allow for moving a +single element out of a tuple-like type. +

        + +

        [ +2009-10-30 Alisdair adds: +]

        + + +
        +

        +The issue of rvalue overloads of get for tuple-like types was briefly +discussed in Santa Cruz. +

        + +

        +The feedback was this would be welcome, but we need full wording for the +other types (pair and array) before advancing. +

        + +

        +I suggest the issue moves to Open from New as it has been considered, +feedback given, and it has not (yet) been rejected as NAD. +

        +
        + + + +

        Proposed resolution:

        +

        +Add the following signature to p2 20.5.1 [tuple.general] +

        + +
        
+template <size_t I, class ... Types>
+typename tuple_element<I, tuple<Types...> >::type&& get(tuple<Types...> &&);
+
        + +

        +And again to 20.5.2.6 [tuple.elem]. +

        + +
        
+template <size_t I, class ... Types>
+typename tuple_element<I, tuple<Types...> >::type&& get(tuple<Types...>&& t);
+
        + +
        +

        +Effects: Equivalent to return std::forward<typename tuple_element<I, tuple<Types...> >::type&&>(get<I>(t)); +

        + + +

        +[Note: If a T in Types is some reference type X&, +the return type is X&, not X&&. +However, if the element type is non-reference type T, +the return type is T&&. — end note] +

        + +
        +
        + +

        +Add the following signature to p1 20.3 [utility] +

        + +
        
+template <size_t I, class T1, class T2>
+typename tuple_element<I, pair<T1,T2> >::type&& get(pair<T1, T2>&&);
+
        + +

        +And to p5 20.3.5 [pair.astuple] +

        + +
        
+template <size_t I, class T1, class T2>
+typename tuple_element<I, pair<T1,T2> >::type&& get(pair<T1, T2>&& p);
+
        + +
        +

        +Returns: If I == 0 returns std::forward<T1&&>(p.first); +if I == 1 +returns std::forward<T2&&>(p.second); otherwise the program is ill-formed. +

        + +

        +Throws: Nothing. +

        + +
        + +
        + +

        +Add the following signature to 23.3 [sequences] <array> synopsis +

        + +
        template <size_t I, class T, size_t N>
+T&& get(array<T,N> &&);
+
        + +

        +And after p8 23.3.1.7 [array.tuple] +

        + +
        template <size_t I, class T, size_t N>
+T&& get(array<T,N> && a);
+
        + +
        +Effects: Equivalent to return std::move(get<I>(a)); +
        +
        + + + + + + +
        +

        1192. basic_string missing definitions for cbegin / cend / crbegin / crend

        +

        Section: 21.4.3 [string.iterators] Status: Tentatively Ready + Submitter: Jonathan Wakely Opened: 2009-08-14 Last modified: 2009-10-29

        +

        View all issues with Tentatively Ready status.

        +

        Discussion:

        +

        +Unlike the containers in clause 23, basic_string has definitions for +begin() and end(), but these have not been updated to include cbegin, +cend, crbegin and crend. +

        + +

        [ +2009-10-28 Howard: +]

        + + +
        +Moved to Tentatively NAD after 5 positive votes on c++std-lib. Added +rationale. +
        + +

        [ +2009-10-28 Alisdair disagrees: +]

        + + +
        +

        +I'm going to have to speak up as the dissenting voice. +

        + +

        +I agree the issue could be handled editorially, and that would be my +preference if Pete feels this is appropriate. Failing that, I really +think this issue should be accepted and moved to ready. The other +begin/end functions all have a semantic definition for this template, +and it is confusing if a small few are missing. +

        + +

        +I agree that an alternative would be to strike all the definitions for +begin/end/rbegin/rend and defer completely to the requirements tables in +clause 23. I think that might be confusing without a forward reference +though, as those tables are defined in a *later* clause than the +basic_string template itself. If someone wants to pursue this I would +support it, but recommend it as a separate issue. +

        + +

        +So my preference is strongly to move Ready over NAD, and a stronger +preference for NAD Editorial if Pete is happy to make these changes. +

        + +
        + +

        [ +2009-10-29 Howard: +]

        + + +
        +Moved to Tentatively Ready after 5 positive votes on c++std-lib. Removed +rationale to mark it NAD. :-) +
        + + + +

        Proposed resolution:

        +

        +Add to 21.4.3 [string.iterators] +

        + +
        iterator       begin();
+const_iterator begin() const;
+const_iterator cbegin() const;
+
        + +

        ...

        + +
        iterator       end();
+const_iterator end() const;
+const_iterator cend() const;
+
        + +

        ...

        + +
        reverse_iterator       rbegin();
+const_reverse_iterator rbegin() const;
+const_reverse_iterator crbegin() const;
+
        + +

        ...

        + +
        reverse_iterator       rend();
+const_reverse_iterator rend() const;
+const_reverse_iterator crend() const;
+
        + +
        + + + + + +
        +

        1193. default_delete cannot be instantiated with incomplete types

        +

        Section: 20.8.14.1 [unique.ptr.dltr] Status: New + Submitter: Daniel Krügler Opened: 2009-08-18 Last modified: 2009-08-22

        +

        View all issues with New status.

        +

        Discussion:

        +

        +According to the general rules of 17.6.3.8 [res.on.functions]/2 b 5 the effects +are undefined, if an incomplete type is used to instantiate a library template. But neither in +20.8.14.1 [unique.ptr.dltr] nor +in any other place of the standard such explicit allowance is given. +Since this template is intended to be instantiated with incomplete +types, this must +be fixed. +

        + + +

        Proposed resolution:

        +

        +Add two new paragraphs directly to 20.8.14.1 [unique.ptr.dltr] (before +20.8.14.1.1 [unique.ptr.dltr.dflt]) with the following +content: +

        + +
        +

        +The class template default_delete serves as the default deleter (destruction policy) for +the class template unique_ptr. +

        + +

        +The template parameter T of default_delete may be an incomplete type. +

        +
        + + + + + +
        +

        1194. Unintended queue constructor

        +

        Section: 23.3.5 [container.adaptors] Status: Ready + Submitter: Howard Hinnant Opened: 2009-08-20 Last modified: 2009-10-20

        +

        View other active issues in [container.adaptors].

        +

        View all other issues in [container.adaptors].

        +

        View all issues with Ready status.

        +

        Discussion:

        +

        +23.3.5.1.1 [queue.defn] has the following queue constructor: +

        + +
        template <class Alloc> explicit queue(const Alloc&);
+
        + +

        +This will be implemented like so: +

        + +
        template <class Alloc> explicit queue(const Alloc& a) : c(a) {}
+
        + +

        +The issue is that Alloc can be anything that a container will construct +from, for example an int. Is this intended to compile? +

        + +
        queue<int> q(5);
+
        + +

        +Before the addition of this constructor, queue<int>(5) would not compile. +I ask, not because this crashes, but because it is new and appears to be +unintended. We do not want to be in a position of accidently introducing this +"feature" in C++0X and later attempting to remove it. +

        + +

        +I've picked on queue. priority_queue and stack have +the same issue. Is it useful to create a priority_queue of 5 +identical elements? +

        + +

        [ +Daniel, Howard and Pablo collaborated on the proposed wording. +]

        + + +

        [ +2009-10 Santa Cruz: +]

        + + +
        +Move to Ready. +
        + + + +

        Proposed resolution:

        + +

        [ +This resolution includes a semi-editorial clean up, giving definitions to members +which in some cases weren't defined since C++98. +This resolution also offers editorially different wording for 976, +and it also provides wording for 1196. +]

        + + +

        +Change container.adaptors, p1: +

        + +
        +The container adaptors each take a Container template parameter, and +each constructor takes a Container reference argument. This container is +copied into the Container member of each adaptor. If the container takes +an allocator, then a compatible allocator may be passed in to the +adaptor's constructor. Otherwise, normal copy or move construction is +used for the container argument. [Note: it is not necessary for an +implementation to distinguish between the one-argument constructor that +takes a Container and the one- argument constructor that takes an +allocator_type. Both forms use their argument to construct an instance +of the container. — end note] +
        + +

        +Change queue.defn, p1: +

        + +
        template <class T, class Container = deque<T> >
+class queue {
+public:
+  typedef typename Container::value_type      value_type;
+  typedef typename Container::reference       reference;
+  typedef typename Container::const_reference const_reference;
+  typedef typename Container::size_type       size_type;
+  typedef Container                           container_type;
+protected:
+  Container c;
+
+public:
+  explicit queue(const Container&);
+  explicit queue(Container&& = Container());
+  queue(queue&& q); : c(std::move(q.c)) {}
+  template <class Alloc> explicit queue(const Alloc&);
+  template <class Alloc> queue(const Container&, const Alloc&);
+  template <class Alloc> queue(Container&&, const Alloc&);
+  template <class Alloc> queue(queue&&, const Alloc&);
+  queue& operator=(queue&& q); { c = std::move(q.c); return *this; }
+
+  bool empty() const          { return c.empty(); }
+  ...
+};
+
        + +

        +Add a new section after 23.3.5.1.1 [queue.defn], [queue.cons]: +

        + +
        +

        queue constructors [queue.cons]

        + +
        explicit queue(const Container& cont);
+
        + +
        + +

        +Effects: Initializes c with cont. +

        + +
        + +
        explicit queue(Container&& cont = Container());
+
        + +
        + +

        +Effects: Initializes c with std::move(cont). +

        + +
        + +
        queue(queue&& q)
+
        + +
        + +

        +Effects: Initializes c with std::move(q.c). +

        + +
        + +

        +For each of the following constructors, +if uses_allocator<container_type, Alloc>::value is false, +then the constructor shall not participate in overload resolution. +

        + +
        template <class Alloc> 
+  explicit queue(const Alloc& a);
+
        + +
        + +

        +Effects: Initializes c with a. +

        + +
        + +
        template <class Alloc> 
+  queue(const container_type& cont, const Alloc& a);
+
        + +
        + +

        +Effects: Initializes c with cont as the first +argument and a as the second argument. +

        + +
        + +
        template <class Alloc> 
+  queue(container_type&& cont, const Alloc& a);
+
        + +
        + +

        +Effects: Initializes c with std::move(cont) as the +first argument and a as the second argument. +

        + +
        + +
        template <class Alloc> 
+  queue(queue&& q, const Alloc& a);
+
        + +
        + +

        +Effects: Initializes c with std::move(q.c) as the +first argument and a as the second argument. +

        + +
        + +
        queue& operator=(queue&& q);
+
        + +
        + +

        +Effects: Assigns c with std::move(q.c). +

        + +

        +Returns: *this. +

        + +
        + + + +
        + +

        +Add to 23.3.5.2.1 [priqueue.cons]: +

        + +
        + +
        priority_queue(priority_queue&& q);
+
        + +
        + +

        +Effects: Initializes c with std::move(q.c) and +initializes comp with std::move(q.comp). +

        + +
        + +

        +For each of the following constructors, +if uses_allocator<container_type, Alloc>::value is false, +then the constructor shall not participate in overload resolution. +

        + +
        template <class Alloc>
+  explicit priority_queue(const Alloc& a);
+
        + +
        + +

        +Effects: Initializes c with a and value-initializes comp. +

        + +
        + +
        template <class Alloc>
+  priority_queue(const Compare& compare, const Alloc& a);
+
        + +
        + +

        +Effects: Initializes c with a and initializes comp +with compare. +

        + +
        + +
        template <class Alloc>
+  priority_queue(const Compare& compare, const Container& cont, const Alloc& a);
+
        + +
        + +

        +Effects: Initializes c with cont as the first argument +and a as the second argument, +and initializes comp with compare. +

        + +
        + +
        template <class Alloc>
+  priority_queue(const Compare& compare, Container&& cont, const Alloc& a);
+
        + +
        + +

        +Effects: Initializes c with std::move(cont) as +the first argument and a as the second argument, +and initializes comp with compare. +

        + +
        + +
        template <class Alloc>
+  priority_queue(priority_queue&& q, const Alloc& a);
+
        + +
        + +

        +Effects: Initializes c with std::move(q.c) as the +first argument and a as the second argument, +and initializes comp with std::move(q.comp). +

        + +
        + +
        priority_queue& operator=(priority_queue&& q);
+
        + +
        + +

        +Effects: Assigns c with std::move(q.c) and +assigns comp with std::move(q.comp). +

        + +

        +Returns: *this. +

        + +
        + +
        + + + + +

        +Change 23.3.5.3.1 [stack.defn]: +

        + +
        template <class T, class Container = deque<T> >
+class stack {
+public:
+  typedef typename Container::value_type      value_type;
+  typedef typename Container::reference       reference;
+  typedef typename Container::const_reference const_reference;
+  typedef typename Container::size_type       size_type;
+  typedef Container                           container_type;
+protected:
+  Container c;
+
+public:
+  explicit stack(const Container&);
+  explicit stack(Container&& = Container());
+  stack(stack&& s);
+  template <class Alloc> explicit stack(const Alloc&);
+  template <class Alloc> stack(const Container&, const Alloc&);
+  template <class Alloc> stack(Container&&, const Alloc&);
+  template <class Alloc> stack(stack&&, const Alloc&);
+  stack& operator=(stack&& s);
+
+  bool empty() const          { return c.empty(); }
+  ...
+};
+
        + +

        +Add a new section after 23.3.5.3.1 [stack.defn], [stack.cons]: +

        + +
        +

        stack constructors [stack.cons]

        + +
        stack(stack&& s);
+
        + +
        + +

        +Effects: Initializes c with std::move(s.c). +

        + +
        + +

        +For each of the following constructors, +if uses_allocator<container_type, Alloc>::value is false, +then the constructor shall not participate in overload resolution. +

        + +
        template <class Alloc> 
+  explicit stack(const Alloc& a);
+
        + +
        + +

        +Effects: Initializes c with a. +

        + +
        + +
        template <class Alloc> 
+  stack(const container_type& cont, const Alloc& a);
+
        + +
        + +

        +Effects: Initializes c with cont as the +first argument and a as the second argument. +

        + +
        + +
        template <class Alloc> 
+  stack(container_type&& cont, const Alloc& a);
+
        + +
        + +

        +Effects: Initializes c with std::move(cont) as the +first argument and a as the second argument. +

        + +
        + +
        template <class Alloc> 
+  stack(stack&& s, const Alloc& a);
+
        + +
        + +

        +Effects: Initializes c with std::move(s.c) as the +first argument and a as the second argument. +

        + +
        + +
        stack& operator=(stack&& s);
+
        + +
        + +

        +Effects: Assigns c with std::move(s.c). +

        + +

        +Returns: *this. +

        + +
        + +
        + + + + + + +
        +

        1197. Can unordered containers have bucket_count() == 0?

        +

        Section: 23.2.5 [unord.req] Status: New + Submitter: Howard Hinnant Opened: 2009-08-24 Last modified: 2009-09-03

        +

        View other active issues in [unord.req].

        +

        View all other issues in [unord.req].

        +

        View all issues with New status.

        +

        Discussion:

        +

        +Table 97 "Unordered associative container requirements" in +23.2.5 [unord.req] says: +

        + +
        + + + + + + + + + + + + + + + + + +
        Table 97 — Unordered associative container requirements +(in addition to container)
        ExpressionReturn typeAssertion/note pre-/post-conditionComplexity
        b.bucket(k)size_typeReturns the index of the bucket in which elements with keys +equivalent to k would be found, +if any such element existed. +Post: the return value shall be +in the range [0, +b.bucket_count()).Constant
        +
        + +

        +What should b.bucket(k) return if b.bucket_count() == 0? +

        + +

        +I believe allowing b.bucket_count() == 0 is important. It is a +very reasonable post-condition of the default constructor, or of a moved-from +container. +

        + +

        +I can think of several reasonable results from b.bucket(k) when +b.bucket_count() == 0: +

        + +
          +
        1. +Return 0. +
          2. +
        2. +Return numeric_limits<size_type>::max(). +
          3. +
        3. +Throw a domain_error. +
          4. +
        4. +Precondition: b.bucket_count() != 0. +
          5. +
        + +

        [ +2009-08-26 Daniel adds: +]

        + + +
        +

        +A forth choice would be to add the pre-condition "b.bucket_count() != 0" +and thus imply undefined behavior if this is violated. +

        + +

        [ +Howard: I like this option too, added to the list. +]

        + + +

        +Further on here my own favorite solution (rationale see below): +

        + +

        Suggested resolution:

        + +

        +[Rationale: I suggest to follow choice (1). The main reason is +that all associative container functions which take a key argument, +are basically free of pre-conditions and non-disrupting, therefore +excluding choices (3) and (4). Option (2) seems a bit unexpected +to me. It would be more natural, if several similar functions +would exist which would also justify the existence of a symbolic +constant like npos for this situation. The value 0 is both simple +and consistent, it has exactly the same role as a past-the-end +iterator value. A typical use-case is: +

        + +
        size_type pos = m.bucket(key);
+if (pos != m.bucket_count()) {
+ ...
+} else {
+ ...
+}
+
        + +

        — end Rationale]

        + +

        +- Change Table 97 in 23.2.5 [unord.req] as follows (Row b.bucket(k), Column "Assertion/..."): +

        + +
        + + + + + + + + + + + + + + + + + +
        Table 97 — Unordered associative container requirements +(in addition to container)
        ExpressionReturn typeAssertion/note pre-/post-conditionComplexity
        b.bucket(k)size_typeReturns the index of the bucket in which elements with keys +equivalent to k would be found, +if any such element existed. +Post: if b.bucket_count() != 0, the return value shall be +in the range [0, +b.bucket_count()), otherwise 0.Constant
        +
        + +
        + + + +

        Proposed resolution:

        +

        +

        + + + + + +
        +

        1198. Container adaptor swap: member or non-member?

        +

        Section: 23.3.5 [container.adaptors] Status: New + Submitter: Pablo Halpern Opened: 2009-08-26 Last modified: 2009-09-30

        +

        View other active issues in [container.adaptors].

        +

        View all other issues in [container.adaptors].

        +

        View all issues with New status.

        +

        Discussion:

        +

        +Under 23.3.5 [container.adaptors] of +N2914 +the member function of swap of queue and stack call: +

        + +
        swap(c, q.c);
+
        + +

        +But under 23.3.5 [container.adaptors] of +N2723 +these members are specified to call: +

        + +
        c.swap(q.c);
+
        + +

        +Neither draft specifies the semantics of member swap for +priority_queue though it is declared. +

        + +

        +Although the distinction between member swap and non-member +swap is not important when these adaptors are adapting standard +containers, it may be important for user-defined containers. +

        +

        +We (Pablo and Howard) feel that +it is more likely for a user-defined container to support a namespace scope +swap than a member swap, and therefore these adaptors +should use the container's namespace scope swap. +

        + +

        [ +2009-09-30 Daniel adds: +]

        + + +
        +The outcome of this issue should be considered with the outcome of 774 both in style and in content (e.g. 774 bullet 9 +suggests to define the semantic of void +priority_queue::swap(priority_queue&) in terms of the member +swap of the container). +
        + + + +

        Proposed resolution:

        +

        [ +Changes written with respect to +N2723. +]

        + + +

        +Change 23.3.5.1.1 [queue.defn]: +

        + +
        template <class T, class Container = deque<T> > 
+class queue {
+   ...
+   void swap(queue&& q) { using std::swap;
+                          c.swap(c, q.c); }
+   ...
+};
+
        + +

        +Change 23.3.5.2 [priority.queue]: +

        + +
        template <class T, class Container = vector<T>, 
+          class Compare = less<typename Container::value_type> > 
+class priority_queue { 
+    ...
+    void swap(priority_queue&& q); { using std::swap;
+                                     swap(c, q.c);
+                                     swap(comp, q.comp); }
+    ...
+};
+
        + +

        +Change 23.3.5.3.1 [stack.defn]: +

        + +
        template <class T, class Container = deque<T> > 
+class stack {
+   ...
+   void swap(stack&& s) { using std::swap;
+                          c.swap(c, s.c); }
+   ...
+};
+
        + + + + + + +
        +

        1199. Missing extended copy constructor in container adaptors

        +

        Section: 23.3.5 [container.adaptors] Status: New + Submitter: Pablo Halpern Opened: 2009-08-26 Last modified: 2009-08-31

        +

        View other active issues in [container.adaptors].

        +

        View all other issues in [container.adaptors].

        +

        View all issues with New status.

        +

        Discussion:

        +

        +queue has a constructor: +

        + +
        template <class Alloc>
+  queue(queue&&, const Alloc&);
+
        + +

        +but it is missing a corresponding constructor: +

        + +
        template <class Alloc>
+  queue(const queue&, const Alloc&);
+
        + +

        +The same is true of priority_queue, and stack. This +"extended copy constructor" is needed for consistency and to ensure that the +user of a container adaptor can always specify the allocator for his adaptor. +

        + + + +

        Proposed resolution:

        +

        [ +This resolution has been harmonized with the proposed resolution to issue +1194 +]

        + + +

        Change 23.3.5.1.1 [queue.defn], p1:

        + +
        template <class T, class Container = deque<T> >
+class queue {
+public:
+  typedef typename Container::value_type      value_type;
+  typedef typename Container::reference       reference;
+  typedef typename Container::const_reference const_reference;
+  typedef typename Container::size_type       size_type;
+  typedef Container                           container_type;
+protected:
+  Container c;
+
+public:
+  explicit queue(const Container&);
+  explicit queue(Container&& = Container());
+  queue(queue&& q);
+
+  template <class Alloc> explicit queue(const Alloc&);
+  template <class Alloc> queue(const Container&, const Alloc&);
+  template <class Alloc> queue(Container&&, const Alloc&);
+  template <class Alloc> queue(const queue&, const Alloc&);
+  template <class Alloc> queue(queue&&, const Alloc&);
+  queue& operator=(queue&& q);
+
+  bool empty() const          { return c.empty(); }
+  ...
+};
+
        + +

        +To the new section [queue.cons], introduced +in 1194, add: +

        + +
        + +
        template <class Alloc> 
+  queue(const queue& q, const Alloc& a);
+
        + +

        +Effects: Initializes c with q.c as the +first argument and a as the second argument. +

        + +
        + +

        Change 23.3.5.2 [priority.queue] as follows (I've an included an editorial change to + move the poorly-placed move-assignment operator):

        + +
        template <class T, class Container = vector<T>,
+          class Compare = less<typename Container::value_type> >
+class priority_queue {
+public:
+  typedef typename Container::value_type      value_type;
+  typedef typename Container::reference       reference;
+  typedef typename Container::const_reference const_reference;
+  typedef typename Container::size_type       size_type;
+  typedef          Container                  container_type;
+protected:
+  Container c;
+  Compare comp;
+
+public:
+  priority_queue(const Compare& x, const Container&);
+  explicit priority_queue(const Compare& x = Compare(), Container&& = Container());
+  template <class InputIterator>
+    priority_queue(InputIterator first, InputIterator last,
+                   const Compare& x, const Container&);
+  template <class InputIterator>
+    priority_queue(InputIterator first, InputIterator last,
+                   const Compare& x = Compare(), Container&& = Container());
+  priority_queue(priority_queue&&);
+  priority_queue& operator=(priority_queue&&);
+  template <class Alloc> explicit priority_queue(const Alloc&);
+  template <class Alloc> priority_queue(const Compare&, const Alloc&);
+  template <class Alloc> priority_queue(const Compare&,
+                                        const Container&, const Alloc&);
+  template <class Alloc> priority_queue(const Compare&,
+                                        Container&&, const Alloc&);
+  template <class Alloc> priority_queue(const priority_queue&, const Alloc&);
+  template <class Alloc> priority_queue(priority_queue&&, const Alloc&);
+
+  priority_queue& operator=(priority_queue&&);
+  ...
+};
+
        + +

        +Add to 23.3.5.2.1 [priqueue.cons]: +

        + +
        + +
        template <class Alloc>
+  explicit priority_queue(const priority_queue& q, const Alloc& a);
+
        + +

        +Effects: Initializes c with q.c as the +first argument and a as the second argument, +and initializes comp with q.comp. +

        + +
        + +

        +Change 23.3.5.3.1 [stack.defn]: +

        + +
        template <class T, class Container = deque<T> >
+class stack {
+public:
+  typedef typename Container::value_type      value_type;
+  typedef typename Container::reference       reference;
+  typedef typename Container::const_reference const_reference;
+  typedef typename Container::size_type       size_type;
+  typedef Container                           container_type;
+protected:
+  Container c;
+
+public:
+  explicit stack(const Container&);
+  explicit stack(Container&& = Container());
+  stack(stack&& s);
+
+  template <class Alloc> explicit stack(const Alloc&);
+  template <class Alloc> stack(const Container&, const Alloc&);
+  template <class Alloc> stack(Container&&, const Alloc&);
+  template <class Alloc> stack(const stack&, const Alloc&);
+  template <class Alloc> stack(stack&&, const Alloc&);
+  stack& operator=(stack&& s);
+
+  bool empty() const          { return c.empty(); }
+  ...
+};
+
        + +

        +To the new section [stack.cons], introduced +in 1194, add: +

        + +
        + +
        template <class Alloc> 
+  stack(const stack& s, const Alloc& a);
+
        + +

        +Effects: Initializes c with s.c as the +first argument and a as the second argument. +

        +
        + + + + + + +
        +

        1200. "surprising" char_traits<T>::int_type requirements

        +

        Section: 21.2.2 [char.traits.typedefs] Status: New + Submitter: Sean Hunt Opened: 2009-09-03 Last modified: 2009-10-28

        +

        View all other issues in [char.traits.typedefs].

        +

        View all issues with New status.

        +

        Discussion:

        +

        +The footnote for int_type in 21.2.2 [char.traits.typedefs] says that +

        + +
        +If eof() +can be held in char_type then some iostreams implementations may give +surprising results. +
        + +

        +This implies that int_type should be a superset of +char_type. However, the requirements for char16_t and char32_t define +int_type to be equal to int_least16_t and int_least32_t respectively. +int_least16_t is likely to be the same size as char_16_t, which may lead +to surprising behavior, even if eof() is not a valid UTF-16 code unit. +The standard should not prescribe surprising behavior, especially +without saying what it is (it's apparently not undefined, just +surprising). The same applies for 32-bit types. +

        + +

        +I personally recommend that behavior be undefined if eof() is a member +of char_type, and another type be chosen for int_type (my personal +favorite has always been a struct {bool eof; char_type c;}). +Alternatively, the exact results of such a situation should be defined, +at least so far that I/O could be conducted on these types as long as +the code units remain valid. Note that the argument that no one streams +char16_t or char32_t is not really valid as it would be perfectly +reasonable to use a basic_stringstream in conjunction with UTF character +types. +

        + +

        [ +2009-10-28 Ganesh provides two possible resolutions and expresses a preference +for the second: +]

        + + +
        +
          +
        1. +

          +Replace 21.2.3.2 [char.traits.specializations.char16_t] para 3 with: +

          + +
          +The member eof() shall return an implementation-defined +constant that cannot appear as a valid UTF-16 code unit +UINT_LEAST16_MAX [Note: this value is guaranteed to +be a permanently reserved UCS-2 code position if UINT_LEAST16_MAX == +0xFFFF and it's not a UCS-2 code position otherwise — end +note]. +
          + +

          +Replace 21.2.3.3 [char.traits.specializations.char32_t] para 3 with: +

          + +
          +The member eof() shall return an implementation-defined constant that +cannot appear as a Unicode code point + +UINT_LEAST32_MAX [Note: this value is guaranteed to be a +permanently reserved UCS-4 code position if UINT_LEAST32_MAX == +0xFFFFFFFF and it's not a UCS-4 code position otherwise — end +note]. +
          +
          2. +
        2. +

          +In 21.2.3.2 [char.traits.specializations.char16_t], in the +definition of char_traits<char16_t> replace the definition of nested +typedef int_type with: +

          + +
          namespace std {
+  template<> struct char_traits<char16_t> {
+    typedef char16_t         char_type;
+    typedef uint_least16_t uint_fast16_t int_type;
+     ...
+
          + +

          +Replace 21.2.3.2 [char.traits.specializations.char16_t] para 3 with: +

          + +
          +The member eof() shall return an implementation-defined +constant that cannot appear as a valid UTF-16 code unit +UINT_FAST16_MAX [Note: this value is guaranteed to +be a permanently reserved UCS-2 code position if UINT_FAST16_MAX == +0xFFFF and it's not a UCS-2 code position otherwise — end +note]. +
          + +

          +In 21.2.3.3 [char.traits.specializations.char32_t], in the +definition of char_traits<char32_t> replace the definition of nested +typedef int_type with: +

          + +
          namespace std {
+  template<> struct char_traits<char32_t> {
+    typedef char32_t         char_type;
+    typedef uint_least32_t uint_fast32_t int_type;
+     ...
+
          + +

          +Replace 21.2.3.3 [char.traits.specializations.char32_t] para 3 with: +

          + +
          +The member eof() shall return an implementation-defined constant that +cannot appear as a Unicode code point + +UINT_FAST32_MAX [Note: this value is guaranteed to be a +permanently reserved UCS-4 code position if UINT_FAST32_MAX == +0xFFFFFFFF and it's not a UCS-4 code position otherwise — end +note]. +
          +
          3. +
        +
        + + + +

        Proposed resolution:

        +

        +

        + + + + + +
        +

        1201. Do we always want to unwrap ref-wrappers in make_tuple

        +

        Section: 20.5.2.4 [tuple.creation], 20.3.4 [pairs] Status: Tentatively NAD Future + Submitter: Alisdair Meredith Opened: 2009-09-05 Last modified: 2009-10-26

        +

        View all issues with Tentatively NAD Future status.

        +

        Discussion:

        +

        +Spotting a recent thread on the boost lists regarding collapsing +optional representations in optional<optional<T>> instances, I wonder if +we have some of the same issues with make_tuple, and now make_pair? +

        + +

        +Essentially, if my generic code in my own library is handed a +reference_wrapper by a user, and my library in turn delegates some logic +to make_pair or make_tuple, then I am going to end up with a pair/tuple +holding a real reference rather than the intended reference wrapper. +

        + +

        +There are two things as a library author I can do at this point: +

        + +
          +
        1. +document my library also has the same reference-wrapper behaviour as +std::make_tuple +
          2. +
        2. +roll my own make_tuple that does not unwrap rereferences, a lost +opportunity to re-use the standard library. +
          3. +
        + +

        +(There may be some metaprogramming approaches my library can use to wrap +the make_tuple call, but all will be significantly more complex than +simply implementing a simplified make_tuple.) +

        + +

        +Now I don't propose we lose this library facility, I think unwrapping +references will be the common behaviour. However, we might want to +consider adding another overload that does nothing special with +ref-wrappers. Note that we already have a second overload of make_tuple +in the library, called tie. +

        + +

        [ +2009-09-30 Daniel adds: +]

        + + +
        +

        +I suggest to change the currently proposed paragraph for +make_simple_pair +

        + +
        template<typename... Types>
+  pair<typename decay<Types>::type...> make_simple_pair(Types&&... t);
+
        +
        +

        +Type requirements: sizeof...(Types) == 2. +Remarks: The program shall be ill-formed, if +sizeof...(Types) != 2. +

        +

        +... +

        +
        +
        + +

        +or alternatively (but with a slightly different semantic): +

        + +
        +
        +Remarks: If sizeof...(Types) != 2, this function shall not +participate in overload resolution. +
        +
        + +

        +to follow a currently introduced style and because the library does +not have yet a specific "Type requirements" element. If such thing +would be considered as useful this should be done as a separate +issue. Given the increasing complexity of either of these wordings +it might be preferable to use the normal two-argument-declaration +style again in either of the following ways: +

        + +
          +
        1. +
          template<class T1, class T2>
+pair<typename decay<T1>::type, typename decay<T2>::type>
+make_simple_pair(T1&& t1, T2&& t2);
+
          +
          2. +
        2. +
          template<class T1, class T2>
+pair<V1, V2> make_simple_pair(T1&& t1, T2&& t2);
+
          +
          +Let V1 be typename decay<T1>::type and V2 be +typename decay<T2>::type. +
          +
          3. +
        + +
        + +

        [ +2009-10 post-Santa Cruz: +]

        + + +
        +Mark as Tentatively NAD Future. +
        + + + +

        Proposed resolution:

        +

        +Add the following function to 20.3.4 [pairs] and signature in +appropriate synopses: +

        + +
        template<typename... Types>
+  pair<typename decay<Types>::type...> make_simple_pair(Types&&... t);
+
        +
        +

        +Type requirements: sizeof...(Types) == 2. +

        +

        +Returns: pair<typename decay<Types>::type...>(std::forward<Types>(t)...). +

        +
        +
        + +

        [ +Draughting note: I chose a variadic representation similar to make_tuple +rather than naming both types as it is easier to read through the +clutter of metaprogramming this way. Given there are exactly two +elements, the committee may prefer to draught with two explicit template +type parameters instead +]

        + + +

        +Add the following function to 20.5.2.4 [tuple.creation] and +signature in appropriate synopses: +

        + +
        template<typename... Types>
+  tuple<typename decay<Types>::type...> make_simple_tuple(Types&&... t);
+
        +
        +

        +Returns: tuple<typename decay<Types>::type...>(std::forward<Types>(t)...). +

        +
        +
        + + + + + +
        +

        1202. integral_constant needs a spring clean

        +

        Section: 20.6.3 [meta.help] Status: New + Submitter: Alisdair Meredith Opened: 2009-09-05 Last modified: 2009-09-06

        +

        View all other issues in [meta.help].

        +

        View all issues with New status.

        +

        Discussion:

        +

        +The specification of integral_constant has been inherited +essentially unchanged from TR1: +

        + +
        template <class T, T v>
+struct integral_constant {
+  static const T value = v;
+  typedef T value_type;
+  typedef integral_constant<T,v> type;
+};
+
        + +

        +In light of 0x language changes there are several things we might +consider changing, notably the form of specification for value. +

        + +

        +The current form requires a static data member have storage allocated +for it, where we could now implement without this using the new enum +syntax: +

        + +
        template <class T, T v>
+struct integral_constant {
+  enum : T { value = v };
+  typedef T value_type;
+  typedef integral_constant type;
+};
+
        + +

        +The effective difference between these two implementation is: +

        + +
          +
        1. +No requirement to allocate storage for data member (which we hope but do +not guarantee compilers strip today) +
          2. + +
        2. +You can no longer take the address of the constant as +&integral_constant<T,v>::value; +
          3. +
        + +

        +Also note the editorial change to drop the explicit qualification of +integral_constant in the typedef type. This makes it quite clear we +mean the current instantiation, and cannot be mistaken for a recursive +metaprogram. +

        + +

        +Even if we don't mandate this implementation, it would be nice to give +vendors freedom under QoI to choose their preferred representation. +

        + +

        +The other side of this issue is if we choose to retain the static +constant form. In that case we should go further and insist on +constexpr, much like we did throughout numeric_limits: +

        + +
        template <class T, T v>
+struct integral_constant {
+  static constexpr T value = v;
+  typedef T value_type;
+  typedef integral_constant type;
+};
+
        + +

        +[Footnote] It turns out constexpr is part of the Tentatively Ready +resolution for 1019. I don't want to interfere with that issue, but +would like a new issue to consider if the fixed-base enum implementation +should be allowed. +

        + +

        [ +2009-09-05 Daniel adds: +]

        + + +
        +

        +I think that the suggested resolution is incomplete and +may have some possible unwanted side-effects. To understand +why, note that integral_constant is completely specified +by code in 20.6.3 [meta.help]. While this is usually considered +as a good thing, let me give a possible user-defined +specialization that would break given the suggested changes: +

        + +
        enum NodeColor { Red, Black };
+
+std::integral_constant<NodeColor, Red> red;
+
        + +

        +The reason why that breaks is due to the fact that +current core language rules does only allow integral +types as enum-bases, see 7.2 [dcl.enum]/2. +

        + +

        +So, I think that we cannot leave the implementation the +freedom to decide which way they would like to provide +the implementation, because that is easily user-visible +(I don't speak of addresses, but of instantiation errors), +therefore if applied, this should be either specified or +wording must be added that gives a note about this +freedom of implementation. +

        + +

        +Another possible disadvantage seems to me that user-expectations +are easy to disappoint if they see a failure +of the test +

        + +
        assert(typeid(std::integral_constant<int, 0>::value) == typeid(int));
+
        + +

        +or of +

        + +
        static_assert(std::is_same<decltype(std::integral_constant<int, 0>::value), const int>::value, "Bad library");
+
        + +
        + + + +

        Proposed resolution:

        + + + + + +
        +

        1204. Global permission to move

        +

        Section: 17.6.3.9 [res.on.arguments] Status: Ready + Submitter: Howard Hinnant Opened: 2009-09-12 Last modified: 2009-10-20

        +

        View all issues with Ready status.

        +

        Discussion:

        +

        +When a library function binds an rvalue reference parameter to an argument, the +library must be able to assume that the bound argument is a temporary, and not +a moved-from lvalue. The reason for this is that the library function must be +able to modify that argument without concern that such modifications will corrupt +the logic of the calling code. For example: +

        + +
        template <class T, class A>
+void
+vector<T, A>::push_back(value_type&& v)
+{
+    // This function should move from v, potentially modifying
+    //   the object v is bound to.
+}
+
        + +

        +If v is truly bound to a temporary, then push_back has the +only reference to this temporary in the entire program. Thus any +modifications will be invisible to the rest of the program. +

        + +

        +If the client supplies std::move(x) to push_back, the onus is +on the client to ensure that the value of x is no longer important to +the logic of his program after this statement. I.e. the client is making a statement +that push_back may treat x as a temporary. +

        + +
        +The above statement is the very foundation upon which move semantics is based. +
        + +

        +The standard is currently lacking a global statement to this effect. I propose +the following addition to 17.6.3.9 [res.on.arguments]: +

        + +
        +

        +Each of the following statements applies to all arguments to functions +defined in the C++ standard library, unless explicitly stated otherwise. +

        +
          +
        • +If an argument to a function has an invalid value (such as a value +outside the domain of the function, or a pointer invalid for its +intended use), the behavior is undefined. +
          • +
        • +If a function argument is described as being an array, the pointer +actually passed to the function shall have a value such that all address +computations and accesses to objects (that would be valid if the pointer +did point to the first element of such an array) are in fact valid. +
          • +
        • +If a function argument binds to an rvalue reference parameter, the C++ +standard library may assume that this parameter is a unique reference +to this argument. If the parameter is a generic parameter of the +form T&&, and an lvalue of type A is bound, +then the binding is considered to be to an lvalue reference +(14.9.2.1 [temp.deduct.call]) and thus not covered by this clause. +[Note: +If a program casts an lvalue to an rvalue while passing that lvalue to +a library function (e.g. move(x)), then the program is effectively +asking the library to treat that lvalue as a temporary. The library is at +liberty to optimize away aliasing checks which might be needed if the argument +were an lvalue. +— end note] +
          • +
        + +
        + +

        +Such a global statement will eliminate the need for piecemeal statements such as +23.2.1 [container.requirements.general]/13: +

        + +
        +An object bound to an rvalue reference parameter of a member function of +a container shall not be an element of that container; no diagnostic +required. +
        + +

        +Additionally this clarifies that move assignment operators need not perform the +traditional if (this != &rhs) test commonly found (and needed) in +copy assignment operators. +

        + +

        [ +2009-09-13 Niels adds: +]

        + + +
        +Note: This resolution supports the change of 27.9.1.3 [filebuf.assign]/1, +proposed by LWG 900. +
        + +

        [ +2009 Santa Cruz: +]

        + + +
        +Move to Ready. +
        + + + +

        Proposed resolution:

        +

        +Add a bullet to 17.6.3.9 [res.on.arguments]: +

        + +
        +

        +Each of the following statements applies to all arguments to functions +defined in the C++ standard library, unless explicitly stated otherwise. +

        +
          +
        • +If an argument to a function has an invalid value (such as a value +outside the domain of the function, or a pointer invalid for its +intended use), the behavior is undefined. +
          • +
        • +If a function argument is described as being an array, the pointer +actually passed to the function shall have a value such that all address +computations and accesses to objects (that would be valid if the pointer +did point to the first element of such an array) are in fact valid. +
          • +
        • +If a function argument binds to an rvalue reference parameter, the C++ +standard library may assume that this parameter is a unique reference +to this argument. If the parameter is a generic parameter of the +form T&&, and an lvalue of type A is bound, +then the binding is considered to be to an lvalue reference +(14.9.2.1 [temp.deduct.call]) and thus not covered by this clause. +[Note: +If a program casts an lvalue to an rvalue while passing that lvalue to +a library function (e.g. move(x)), then the program is effectively +asking the library to treat that lvalue as a temporary. The library is at +liberty to optimize away aliasing checks which might be needed if the argument +were an lvalue. +— end note] +
          • +
        +
        + +

        +Delete 23.2.1 [container.requirements.general]/13: +

        + +
        +An object bound to an rvalue reference parameter of a member function of +a container shall not be an element of that container; no diagnostic +required. +
        + + + + + + +
        +

        1205. Some algorithms could more clearly document their handling of empty ranges

        +

        Section: 25 [algorithms] Status: New + Submitter: Alisdair Meredith Opened: 2009-09-13 Last modified: 2009-09-13

        +

        View other active issues in [algorithms].

        +

        View all other issues in [algorithms].

        +

        View all issues with New status.

        +

        Discussion:

        +

        +There are a number of algorithms whose result might depend on the +handling of an empty range. In some cases the result is not clear, +while in others it would help readers to clearly mention the result +rather than require some subtle intuition of the supplied wording. +

        + +

        +25.2.1 [alg.all_of] +

        + +
        +Returns: true if pred(*i) is true for every +iterator i in the range [first,last), ... +
        + +

        +What does this mean if the range is empty? +

        + +

        +I believe that we intend this to be true and suggest a +non-normative note to clarify: +

        + +

        +Add to p1 25.2.1 [alg.all_of]: +

        + +
        +[Note: Returns true if [first,last) is empty. +— end note] +
        + +

        +25.2.3 [alg.none_of] +

        + +
        +Returns: true if pred(*i) is false for every +iterator i in the range [first,last), ... +
        + +

        +What does this mean if the range empty? +

        + +

        +I believe that we intend this to be true and suggest a +non-normative note to clarify: +

        + +

        +Add to p1 25.2.3 [alg.none_of]: +

        + +
        +[Note: Returns true if [first,last) is empty. +— end note] +
        + +

        +25.2.2 [alg.any_of] +

        + +

        +The specification for an empty range is actually fairly clear in this +case, but a note wouldn't hurt and would be consistent with proposals +for all_of/none_of algorithms. +

        + +

        +Add to p1 25.2.2 [alg.any_of]: +

        + +
        +[Note: Returns false if [first,last) is empty. +— end note] +
        + +

        +25.2.6 [alg.find.end] +

        + +

        +what does this mean if [first2,last2) is empty? +

        + +

        +I believe the wording suggests the algorithm should return +last1 in this case, but am not 100% sure. Is this in fact the +correct result anyway? Surely an empty range should always match and the +naive expected result would be first1? +

        + +

        +My proposed wording is a note to clarify the current semantic: +

        + +

        +Add to p2 25.2.6 [alg.find.end]: +

        + +
        +[Note: Returns last1 if [first2,last2) is +empty. — end note] +
        + +

        +I would prefer a normative wording treating empty ranges specially, but +do not believe we can change semantics at this point in the process, +unless existing implementations actually yield this result: +

        + +

        +Alternative wording: (NOT a note) +

        +

        +Add to p2 25.2.6 [alg.find.end]: +

        +
        +Returns first1 if [first2,last2) is empty. +
        + +

        +25.2.7 [alg.find.first.of] +

        + +

        +The phrasing seems precise when [first2, last2) is empty, but a small +note to confirm the reader's understanding might still help. +

        + +

        +Add to p2 25.2.7 [alg.find.first.of] +

        +
        +[Note: Returns last1 if [first2,last2) is +empty. — end note] +
        + +

        +25.2.12 [alg.search] +

        + +

        +What is the expected result if [first2, last2) is empty? +

        + +

        +I believe the wording suggests the algorithm should return last1 in this +case, but am not 100% sure. Is this in fact the correct result anyway? +Surely an empty range should always match and the naive expected result +would be first1? +

        + +

        +My proposed wording is a note to clarify the current semantic: +

        + +

        +Add to p2 25.2.12 [alg.search]: +

        + +
        +[Note: Returns last1 if [first2,last2) is +empty. — end note] +
        + +

        +Again, I would prefer a normative wording treating empty ranges +specially, but do not believe we can change semantics at this point in +the process, unless existing implementations actually yield this result: +

        + +

        +Alternative wording: (NOT a note) +

        +

        +Add to p2 25.2.12 [alg.search]: +

        + +
        +Returns first1 if [first2,last2) is empty. +
        + +

        +25.3.13 [alg.partitions] +

        + +

        +Is an empty range partitioned or not? +

        + +

        +Proposed wording: +

        + +

        +Add to p1 25.3.13 [alg.partitions]: +

        + +
        +[Note: Returns true if [first,last) is empty. +— end note] +
        + +

        +25.4.5.1 [includes] +

        + +
        +Returns: true if every element in the range +[first2,last2) is contained in the range +[first1,last1). ... +
        + +

        +I really don't know what this means if [first2,last2) is empty. +I could loosely guess that this implies empty ranges always match, and +my proposed wording is to clarify exactly that: +

        + +

        +Add to p1 25.4.5.1 [includes]: +

        + +
        +[Note: Returns true if [first2,last2) is empty. +— end note] +
        + +

        +25.4.6.2 [pop.heap] +

        + +

        +The effects clause is invalid if the range [first,last) is empty, unlike +all the other heap alogorithms. The should be called out in the +requirements. +

        + +

        +Proposed wording: +

        +

        +Revise p2 25.4.6.2 [pop.heap] +

        + +
        +Requires: The range [first,last) shall be a valid +non-empty heap. +
        + +

        +[Editorial] Reverse order of 25.4.6.2 [pop.heap] p1 and p2. +

        + +

        +25.4.7 [alg.min.max] +

        + +

        +minmax_element does not clearly specify behaviour for an empty +range in the same way that min_element and max_element do. +

        + +

        +Add to p31 25.4.7 [alg.min.max]: +

        + +
        +Returns make_pair(first, first) if first == last. +
        + +

        +25.4.8 [alg.lex.comparison] +

        + +

        +The wording here seems quite clear, especially with the sample algorithm +implementation. A note is recommended purely for consistency with the +rest of these issue resolutions: +

        + +

        +Add to p1 25.4.8 [alg.lex.comparison]: +

        + +
        +[Note: An empty sequence is lexicographically less than any other +non-empty sequence, but not to another empty sequence. — end note] +
        + + +

        Proposed resolution:

        +

        +Add to p1 25.2.1 [alg.all_of]: +

        +
        +[Note: Returns true if [first,last) is empty. +— end note] +
        + +

        +Add to p1 25.2.2 [alg.any_of]: +

        +
        +[Note: Returns false if [first,last) is empty. +— end note] +
        + +

        +Add to p1 25.2.3 [alg.none_of]: +

        +
        +[Note: Returns true if [first,last) is empty. +— end note] +
        + +

        +Add to p2 25.2.6 [alg.find.end]: +

        +
        +[Note: Returns last1 if [first2,last2) is +empty. — end note] +
        + +

        +Add to p2 25.2.7 [alg.find.first.of] +

        +
        +[Note: Returns last1 if [first2,last2) is +empty. — end note] +
        + +

        +Add to p2 25.2.12 [alg.search]: +

        +
        +[Note: Returns last1 if [first2,last2) is +empty. — end note] +
        + +

        +Add to p1 25.3.13 [alg.partitions]: +

        +
        +[Note: Returns true if [first,last) is empty. +— end note] +
        + +

        +Add to p1 25.4.5.1 [includes]: +

        +
        +[Note: Returns true if [first2,last2) is empty. +— end note] +
        + +

        +Revise p2 25.4.6.2 [pop.heap] +

        +
        +Requires: The range [first,last) shall be a valid +non-empty heap. +
        + +

        +[Editorial] +

        +
        +Reverse order of 25.4.6.2 [pop.heap] p1 and p2. +
        + +

        +Add to p31 25.4.7 [alg.min.max]: +

        +
        +Returns make_pair(first, first) if first == last. +
        + +

        +Add to p1 25.4.8 [alg.lex.comparison]: +

        +
        +[Note: An empty sequence is lexicographically less than any other +non-empty sequence, but not less than another empty sequence. — +end note] +
        + + + + + + +
        +

        1206. Incorrect requires for move_backward and copy_backward

        +

        Section: 25.3.2 [alg.move] Status: New + Submitter: Howard Hinnant Opened: 2009-09-13 Last modified: 2009-09-13

        +

        View all issues with New status.

        +

        Discussion:

        +

        +25.3.2 [alg.move], p6 says: +

        + +
        +
        template<class BidirectionalIterator1, class BidirectionalIterator2>
+  BidirectionalIterator2
+    move_backward(BidirectionalIterator1 first,
+                  BidirectionalIterator1 last,
+                  BidirectionalIterator2 result);
+
        +
        +

        ...

        +

        +Requires: result shall not be in the range +[first,last). +

        +
        +
        + +

        +This is essentially an "off-by-one" error. +

        + +

        +When result == last, which +is allowed by this specification, then the range [first, last) +is being move assigned into the range [first, last). The move +(forward) algorithm doesn't allow self move assignment, and neither should +move_backward. So last should be included in the range which +result can not be in. +

        + +

        +Conversely, when result == first, which is not allowed by this +specification, then the range [first, last) +is being move assigned into the range [first - (last-first), first). +I.e. into a non-overlapping range. Therefore first should +not be included in the range which result can not be in. +

        + +

        +The same argument applies to copy_backward though copy assigning elements +to themselves (result == last) should be harmless (though is disallowed +by copy). +

        + + + +

        Proposed resolution:

        +

        +Change 25.3.2 [alg.move], p6: +

        + +
        +
        template<class BidirectionalIterator1, class BidirectionalIterator2>
+  BidirectionalIterator2
+    move_backward(BidirectionalIterator1 first,
+                  BidirectionalIterator1 last,
+                  BidirectionalIterator2 result);
+
        +
        +

        ...

        +

        +Requires: result shall not be in the range +[(first,last]). +

        +
        +
        + +

        +Change 25.3.1 [alg.copy], p13: +

        + +
        +
        template<class BidirectionalIterator1, class BidirectionalIterator2>
+  BidirectionalIterator2
+    copy_backward(BidirectionalIterator1 first,
+                  BidirectionalIterator1 last,
+                  BidirectionalIterator2 result);
+
        +
        +

        ...

        +

        +Requires: result shall not be in the range +[(first,last]). +

        +
        +
        + + + + + +
        +

        1207. Underspecified std::list operations?

        +

        Section: 23.3.4.4 [list.ops] Status: New + Submitter: Loďc Joly Opened: 2009-09-13 Last modified: 2009-09-19

        +

        View other active issues in [list.ops].

        +

        View all other issues in [list.ops].

        +

        View all issues with New status.

        +

        Discussion:

        +

        +It looks to me like some operations of std::list +(sort, reverse, remove, unique & +merge) do not specify the validity of iterators, pointers & +references to elements of the list after those operations. Is it implied +by some other text in the standard? +

        + +

        +I believe sort & reverse do not invalidating +anything, remove & unique only invalidates what +refers to erased elements, merge does not invalidate anything +(with the same precision as splice for elements who changed of +container). Are those assumptions correct ? +

        + + +

        Proposed resolution:

        + + + + + +
        +

        1208. valarray initializer_list constructor has incorrect effects

        +

        Section: 26.6.2.1 [valarray.cons] Status: Tentatively Ready + Submitter: Howard Hinnant Opened: 2009-09-23 Last modified: 2009-10-29

        +

        View all other issues in [valarray.cons].

        +

        View all issues with Tentatively Ready status.

        +

        Discussion:

        +

        +26.6.2.1 [valarray.cons] says: +

        + +
        +
        valarray(initializer_list<T> il);
+
        +
        +Effects: Same as valarray(il.begin(), il.end()). +
        +
        + +

        +But there is no valarray constructor taking two const T*. +

        + +

        [ +2009-10-29 Howard: +]

        + + +
        +Moved to Tentatively Ready after 6 positive votes on c++std-lib. +
        + + +

        Proposed resolution:

        +

        +Change 26.6.2.1 [valarray.cons]: +

        + +
        +
        valarray(initializer_list<T> il);
+
        +
        +Effects: Same as valarray(il.begin(), il.endsize()). +
        +
        + + + + + +
        +

        1209. match_results should be moveable

        +

        Section: 28.10.1 [re.results.const] Status: New + Submitter: Stephan T. Lavavej Opened: 2009-09-15 Last modified: 2009-09-21

        +

        View all issues with New status.

        +

        Discussion:

        +

        +In Working Draft +N2914, +match_results lacks a move constructor and move +assignment operator. Because it owns dynamically allocated memory, it +should be moveable. +

        + +

        +As far as I can tell, this isn't tracked by an active issue yet; Library +Issue 723 doesn't talk about match_results. +

        + +

        [ +2009-09-21 Daniel provided wording. +]

        + + + +

        Proposed resolution:

        +
          +
        1. +

          +Add the following member declarations to 28.10 [re.results]/3: +

          + +
          // 28.10.1, construct/copy/destroy:
+explicit match_results(const Allocator& a = Allocator());
+match_results(const match_results& m);
+match_results(match_results&& m);
+match_results& operator=(const match_results& m);
+match_results& operator=(match_results&& m);
+~match_results();
+
          +
          2. + +
        2. +

          +Add the following new prototype descriptions to 28.10.1 [re.results.const] +using the table numbering of +N2723: +

          + +
          +
          match_results(const match_results& m);
+
          + +
          +4 Effects: Constructs an object of class match_results, as a +copy of m. +
          + +
          match_results(match_results&& m);
+
          + +
          +

          +5 Effects: Move-constructs an object of class match_results +from m satisfying the same postconditions as Table 132. Additionally +the stored Allocator value is move constructed from m.get_allocator(). +After the initialization of *this sets m to an unspecified but valid +state. +

          + +

          +6 Throws: Nothing if the allocator's move constructor throws nothing. +

          +
          + +
          match_results& operator=(const match_results& m);
+
          + +
          +7 Effects: Assigns m to *this. The postconditions of this function are +indicated in Table 132. +
          + +
          match_results& operator=(match_results&& m);
+
          + +
          +

          +8 Effects: Move-assigns m to *this. The postconditions of this +function are indicated in Table 132. After the assignment, m is in +a valid but unspecified state. +

          + +

          +9 Throws: Nothing. +

          +
          +
          +
          3. + +
        + + + + + +
        +

        1210. iterator reachability should not require a container

        +

        Section: 24.2 [iterator.requirements] Status: New + Submitter: Alisdair Meredith Opened: 2009-09-18 Last modified: 2009-09-19

        +

        View other active issues in [iterator.requirements].

        +

        View all other issues in [iterator.requirements].

        +

        View all issues with New status.

        +

        Discussion:

        +

        +p6 Iterator requirements 24.2 [iterator.requirements] +

        + +
        +An iterator j is called reachable from an iterator i if and only if +there is a finite sequence of applications of the expression ++i that +makes i == j. If j is reachable from i, they refer to the same +container. +
        + +

        +A good example would be stream iterators, which do not refer to a +container. Typically, the end iterator from a range of stream iterators +will compare equal for many such ranges. I suggest striking the second +sentence. +

        + +

        +An alternative wording might be: +

        + +
        +If j is reachable from i, and both i and +j are dereferencable iterators, then they refer to the same +range. +
        + + +

        Proposed resolution:

        +

        +Change 24.2 [iterator.requirements], p6: +

        + +
        +An iterator j is called reachable from an iterator +i if and only if there is a finite sequence of applications of +the expression ++i that makes i == j. If +j is reachable from i, they refer to the same +container. +
        + + + + + +
        +

        1211. move iterators should be restricted as input iterators

        +

        Section: 24.5.3.1 [move.iterator] Status: Open + Submitter: Alisdair Meredith Opened: 2009-09-18 Last modified: 2009-10-26

        +

        View all other issues in [move.iterator].

        +

        View all issues with Open status.

        +

        Discussion:

        +

        +I contend that while we can support both bidirectional and random access +traversal, the category of a move iterator should never be better than +input_iterator_tag. +

        + +

        +The contentious point is that you cannot truly have a multipass property +when values are moved from a range. This is contentious if you view a +moved-from object as still holding a valid value within the range. +

        + +

        +The second reason comes from the Forward Iterator requirements table: +

        + +
        +

        +Forward iterators 24.2.3 [forward.iterators] +

        + +

        +Table 102 -- Forward iterator requirements +

        + +
        +For expression *a the return type is: +"T& if X is mutable, otherwise const T&" +
        +
        + +

        +There is a similar constraint on a->m. +

        + +

        +There is no support for rvalue references, nor do I believe their should +be. Again, opinions may vary but either this table or the definition of +move_iterator need updating. +

        + +

        +Note: this requirement probably need updating anyway if we wish to +support proxy iterators but I am waiting to see a new working paper +before filing that issue. +

        + +

        [ +2009-10 post-Santa Cruz: +]

        + + +
        +Move to Open. Howard to put his rationale mentioned above into the issue +as a note. +
        + +

        [ +2009-10-26 Howard adds: +]

        + + +
        +

        +vector::insert(pos, iter, iter) is significantly more effcient when +iter is a random access iterator, as compared to when it is an +input iterator. +

        + +

        +When iter is an input iterator, the best algorithm +is to append the inserted range to the end of the vector using +push_back. This may involve several reallocations before the input +range is exhausted. After the append, then one can use std::rotate +to place the inserted range into the correct position in the vector. +

        + +

        +But when iter is a random access iterator, the best algorithm +is to first compute the size of the range to be inserted (last - first), +do a buffer reallocation if necessary, scoot existing elements in the vector +down to make the "hole", and then insert the new elements directly to their correct +place. +

        + +
        +The insert-with-random-access-iterators algorithm is considerably more efficient +than the insert-with-input-iterators algorithm +
        + +

        +Now consider: +

        + +
        vector<A> v;
+//  ... build up a large vector of A ...
+vector<A> temp;
+//  ... build up a large temporary vector of A to later be inserted ...
+typedef move_iterator<vector<A>::iterator> MI;
+//  Now insert the temporary elements:
+v.insert(v.begin() + N, MI(temp.begin()), MI(temp.end()));
+
        + +

        +A major motivation for using move_iterator in the above example is the +expectation that A is cheap to move but expensive to copy. I.e. the +customer is looking for high performance. If we allow vector::insert +to subtract two MI's to get the distance between them, the customer enjoys +substantially better performance, compared to if we say that vector::insert +can not subtract two MI's. +

        + +

        +I can find no rationale for not giving this performance boost to our customers. +Therefore I am strongly against restricting move_iterator to the +input_iterator_tag category. +

        + +

        +I believe that the requirement that forward +iterators have a dereference that returns an lvalue reference to cause unacceptable +pessimization. For example vector<bool>::iterator also does not return +a bool& on dereference. Yet I am not aware of a single vendor that +is willing to ship vector<bool>::iterator as an input iterator. +Everyone classifies it as a random access iterator. Not only does this not +cause any problems, it prevents significant performance problems. +

        + +
        + + + +

        Proposed resolution:

        +

        +Class template move_iterator 24.5.3.1 [move.iterator] +

        + +
        namespace std {
+template <class Iterator>
+class move_iterator {
+public:
+ ...
+ typedef typename iterator_traits<Iterator>::iterator_category input_iterator_tag iterator_category;
+
        + + + + + +
        +

        1212. result of post-increment/decrement operator

        +

        Section: 24.2 [iterator.requirements] Status: New + Submitter: Alisdair Meredith Opened: 2009-09-18 Last modified: 2009-09-19

        +

        View other active issues in [iterator.requirements].

        +

        View all other issues in [iterator.requirements].

        +

        View all issues with New status.

        +

        Discussion:

        +

        Forward iterator and bidirectional iterator place different +requirements on the result of post-increment/decrement operator. The +same form should be used in each case. +

        + +

        +Merging row from: +

        + +
        Table 102 -- Forward iterator requirements
+Table 103 -- Bidirectional iterator requirements
+
+    r++ : convertible to const X&
+    r-- : convertible to const X&
+    
+    *r++ : T& if X is mutable, otherwise const T&
+    *r-- : convertible to T
+
        + + +

        Proposed resolution:

        + + + + + +
        +

        1213. Meaning of valid and singular iterator underspecified

        +

        Section: 24.2 [iterator.requirements] Status: New + Submitter: Daniel Krügler Opened: 2009-09-19 Last modified: 2009-09-19

        +

        View other active issues in [iterator.requirements].

        +

        View all other issues in [iterator.requirements].

        +

        View all issues with New status.

        +

        Discussion:

        +

        +The terms valid iterator and singular aren't +properly defined. The fuzziness of those terms became even worse +after the resolution of 208 (including further updates by 278). In +24.2 [iterator.requirements] as of +N2723 +the standard says now: +

        + +
        +

        +5 - These values are called past-the-end values. Values of an iterator i for +which the expression *i is defined are called dereferenceable. The library +never assumes that past-the-end values are dereferenceable. Iterators +can also have singular values that are not associated with any +container. [...] Results of most expressions are undefined for singular +values; the only exceptions are destroying an iterator that holds a +singular value and the assignment of a non-singular value to an iterator +that holds a singular value. [...] Dereferenceable values are always +non-singular. +

        + +

        +10 - An invalid iterator is an iterator that may be singular. +

        +
        + +

        +First, issue 208 intentionally removed the earlier constraint that past-the-end +values are always non-singular. The reason for this was to support null +pointers as past-the-end iterators of e.g. empty sequences. But there +seem to exist different views on what a singular (iterator) value is. E.g. +according to the SGI definition +a null pointer is not a singular value: +

        + +
        +Dereferenceable iterators are always nonsingular, but the converse is +not true. +For example, a null pointer is nonsingular (there are well defined operations +involving null pointers) even thought it is not dereferenceable. +
        + +

        +and proceeds: +

        + +
        +An iterator is valid if it is dereferenceable or past-the-end. +
        + +

        +Even if the standard prefers a different meaning of singular here, the +change was +incomplete, because by restricting feasible expressions of singular +iterators to +destruction and assignment isn't sufficient for a past-the-end +iterator: Of-course +it must still be equality-comparable and in general be a readable value. +

        + +

        +Second, the standard doesn't clearly say whether a past-the-end value is +a valid iterator or not. E.g. 20.8.13 [specialized.algorithms]/1 says: +

        + +
        +In all of the following algorithms, the formal template parameter +ForwardIterator +is required to satisfy the requirements of a forward iterator (24.1.3) +[..], and is +required to have the property that no exceptions are thrown from [..], or +dereference of valid iterators. +
        + +

        +The standard should make better clear what "singular pointer" and "valid +iterator" means. The fact that the meaning of a valid value +has a core language meaning doesn't imply that for an iterator concept +the term "valid iterator" has the same meaning. +

        + +

        +Let me add a final example: In X [allocator.concepts.members] of +N2914 +we find: +

        + +
        pointer X::allocate(size_type n);
+
        + +
        +11 Returns: a pointer to the allocated memory. [Note: if n == 0, the return +value is unspecified. —end note] +
        + +

        +[..] +

        + +
        void X::deallocate(pointer p, size_type n);
+
        + +
        +Preconditions: p shall be a non-singular pointer value obtained from a call +to allocate() on this allocator or one that compares equal to it. +
        +
        + +

        +If singular pointer value would include null pointers this make the +preconditions +unclear if the pointer value is a result of allocate(0): Since the return value +is unspecified, it could be a null pointer. Does that mean that programmers +need to check the pointer value for a null value before calling deallocate? +

        + + +

        Proposed resolution:

        + + + + + +
        +

        1214. Insufficient/inconsistent key immutability requirements for associative containers

        +

        Section: 23.2.4 [associative.reqmts] Status: New + Submitter: Daniel Krügler Opened: 2009-09-20 Last modified: 2009-09-20

        +

        View other active issues in [associative.reqmts].

        +

        View all other issues in [associative.reqmts].

        +

        View all issues with New status.

        +

        Discussion:

        +

        +Scott Meyers' mentions on a recent posting on c.s.c++ +some arguments that point to an incomplete resolution +of 103 and to an inconsistency of requirements on keys in ordered and +unordered associative +containers: +

        + +
        +

        +1) 103 introduced the term immutable without defining it in a unique manner in +23.2.4 [associative.reqmts]/5: +

        + +
        +[..] Keys in an associative container are immutable. +
        + +

        +According to conventional dictionaries immutable is an unconditional way of +saying that something cannot be changed. So without any further explicit +allowance a user always runs into undefined behavior if (s)he attempts +to modify such a key. IMO this was not the intend of the committee to resolve +103 in that way because the comments suggest an interpretation that +should give any user the freedom to modify the key in an explicit way +provided it would not affect the sort order in that container. +

        + +

        +2) Another observation was that surprisingly no similar 'safety guards' +exists against unintentional key changes for the unordered associative +containers, specifically there is no such requirement as in +23.2.4 [associative.reqmts]/6 that "both iterator and const_iterator are constant +iterators". But the need for such protection against unintentional +changes as well as the constraints in which manner any explicit +changes may be performed are both missing and necessary, because +such changes could potentially change the equivalence of keys that +is measured by the hasher and key_equal. +

        + +

        +I suggest to fix the unconditional wording involved with "immutable keys" +by at least adding a hint for the reader that users may perform such +changes in an explicit manner and to perform similar wording changes +as 103 did for the ordered associative containers also for the unordered +containers. +

        +
        + + +

        Proposed resolution:

        + + + + + +
        +

        1215. list::merge with unequal allocators

        +

        Section: 23.3.4.4 [list.ops] Status: New + Submitter: Pablo Halpern Opened: 2009-09-24 Last modified: 2009-09-24

        +

        View other active issues in [list.ops].

        +

        View all other issues in [list.ops].

        +

        View all issues with New status.

        +

        Discussion:

        +

        +In Bellevue (I think), we passed +N2525, +which, among other things, specifies that the behavior of +list::splice is undefined if the allocators of the two lists +being spliced do not compare equal. The same rationale should apply to +list::merge. The intent of list::merge (AFAIK) is to +move nodes from one sorted list into another sorted +list without copying the elements. This is possible only if the +allocators compare equal. +

        + + +

        Proposed resolution:

        +

        +Relative to the August 2009 WP, +N2857, +change 23.3.4.4 [list.ops], +paragraphs 22-25 as follows: +

        + +
        +
        void merge(list&& x);
+template <class Compare> void merge(list&& x, Compare comp);
+
        +
        +

        +Requires: both the list and the argument list shall be sorted +according to operator< or comp. +

        +

        +Effects: If (&x == this) does nothing; otherwise, merges the +two sorted ranges [begin(), end()) and [x.begin(), +x.end()). The result is a range in which the elements will be +sorted in non-decreasing order according to the ordering defined by +comp; that is, for every iterator i, in the range other than the +first, the condition comp(*i, *(i - 1)) will be +false. +

        +

        +Remarks: Stable. If (&x != this) the range [x.begin(), x.end()) is +empty after the merge. No elements are copied by this operation. +The behavior is undefined if this->get_allocator() != +x.get_allocator(). +

        +

        +Complexity: At most size() + x.size() - 1 applications of comp +if (&x != this); otherwise, no applications of comp are performed. If an +exception is thrown other than by a comparison there are no effects. +

        +
        +
        + + + + + +
        +

        1216. LWG 1066 Incomplete?

        +

        Section: 18.8.6 [except.nested] Status: Ready + Submitter: Pete Becker Opened: 2009-09-25 Last modified: 2009-10-20

        +

        View other active issues in [except.nested].

        +

        View all other issues in [except.nested].

        +

        View all issues with Ready status.

        +

        Discussion:

        +

        +LWG 1066 adds [[noreturn]] to a bunch of things. +It doesn't add it to rethrow_nested(), which seems like an obvious +candidate. I've made the changes indicated in the issue, and haven't +changed rethrow_nested(). +

        + +

        [ +2009 Santa Cruz: +]

        + + +
        +Move to Ready. +
        + + + +

        Proposed resolution:

        +

        +Add [[noreturn]] to rethrow_nested() in 18.8.6 [except.nested]. +

        + + + + + +
        +

        1218. mutex destructor synchronization

        +

        Section: 30.4.1 [thread.mutex.requirements] Status: New + Submitter: Jeffrey Yasskin Opened: 2009-09-30 Last modified: 2009-09-30

        +

        View other active issues in [thread.mutex.requirements].

        +

        View all other issues in [thread.mutex.requirements].

        +

        View all issues with New status.

        +

        Discussion:

        +

        +If an object *o contains a mutex mu and a +correctly-maintained reference count c, is the following code +safe? +

        + +
        o->mu.lock();
+bool del = (--(o->c) == 0);
+o->mu.unlock();
+if (del) { delete o; }
+
        + +

        +If the implementation of mutex::unlock() can touch the mutex's +memory after the moment it becomes free, this wouldn't be safe, and +"Construction and destruction of an object of a Mutex type need not be +thread-safe" 30.4.1 [thread.mutex.requirements] may imply that +it's not safe. Still, it's useful to allow mutexes to guard reference +counts, and if it's not allowed, users are likely to write bugs. +

        + + +

        Proposed resolution:

        +

        +

        + + + + + +
        +

        1219. unique_lock::lock and resource_deadlock_would_occur

        +

        Section: 30.4.3.2.2 [thread.lock.unique.locking] Status: New + Submitter: Jeffrey Yasskin Opened: 2009-09-30 Last modified: 2009-09-30

        +

        View other active issues in [thread.lock.unique.locking].

        +

        View all other issues in [thread.lock.unique.locking].

        +

        View all issues with New status.

        +

        Discussion:

        +

        +unique_lock::lock and friends raise +"resource_deadlock_would_occur -- if the current thread already +owns the mutex (i.e., on entry, owns is true)." 1) +The current thread owning a mutex is not the same as any particular +unique_lock::owns being true. 2) There's no need to +raise this exception for a recursive_mutex if owns is +false. 3) If owns is true, we need to raise some +exception or the unique_lock will lose track of whether to unlock itself +on destruction, but "deadlock" isn't it. For (3), s/bool owns/int +ownership_level/ would fix it. +

        + + +

        Proposed resolution:

        + + + + + +
        +

        1220. What does condition_variable wait on?

        +

        Section: 30.5 [thread.condition] Status: Tentatively Ready + Submitter: Jeffrey Yasskin Opened: 2009-09-30 Last modified: 2009-11-06

        +

        View other active issues in [thread.condition].

        +

        View all other issues in [thread.condition].

        +

        View all issues with Tentatively Ready status.

        +

        Discussion:

        +

        +"Class condition_variable provides a condition variable that can only +wait on an object of type unique_lock" should say "...object of type +unique_lock<mutex>" +

        + +

        [ +2009-11-06 Howard adds: +]

        + + +
        +Moved to Tentatively Ready after 5 positive votes on c++std-lib. +
        + + + +

        Proposed resolution:

        +

        +Change 30.5 [thread.condition], p1: +

        + +
        +Condition variables provide synchronization primitives used to block a +thread until notified by some other thread that some condition is met or +until a system time is reached. Class condition_variable +provides a condition variable that can only wait on an object of type +unique_lock<mutex>, allowing maximum +efficiency on some platforms. Class condition_variable_any +provides a general condition variable that can wait on objects of +user-supplied lock types. +
        + + + + + +
        +

        1221. condition_variable wording

        +

        Section: 30.5.1 [thread.condition.condvar] Status: New + Submitter: Jeffrey Yasskin Opened: 2009-09-30 Last modified: 2009-09-30

        +

        View other active issues in [thread.condition.condvar].

        +

        View all other issues in [thread.condition.condvar].

        +

        View all issues with New status.

        +

        Discussion:

        +

        +30.5.1 [thread.condition.condvar] says: +

        + +
        +
        ~condition_variable();
+
        +
        +Precondition: There shall be no thread blocked on *this. +[Note: That is, all threads shall have been notified; they may +subsequently block on the lock specified in the wait. Beware that +destroying a condition_variable object while the corresponding +predicate is false is likely to lead to undefined behavior. +— end note] +
        +
        + +

        +The text hasn't introduced the notion of a "corresponding predicate" +yet. +

        + + +

        Proposed resolution:

        + + + + + +
        +

        1222. condition_variable incorrect effects for exception safety

        +

        Section: 30.5 [thread.condition] Status: New + Submitter: Jeffrey Yasskin Opened: 2009-09-30 Last modified: 2009-09-30

        +

        View other active issues in [thread.condition].

        +

        View all other issues in [thread.condition].

        +

        View all issues with New status.

        +

        Discussion:

        +

        +30.5.1 [thread.condition.condvar] says: +

        + +
        +
        void wait(unique_lock<mutex>& lock);
+
        +
        +

        ...

        +

        +Effects: +

        +
          +
        • ...
          • +
        • +If the function exits via an exception, lock.unlock() shall be +called prior to exiting the function scope. +
          • +
        +
        +
        + +

        +Should that be lock.lock()? +

        + + +

        Proposed resolution:

        + +

        +Change 30.5.1 [thread.condition.condvar] p10: +

        + +
        +
        void wait(unique_lock<mutex>& lock);
+
        +
        +

        ...

        +

        +Effects: +

        +
          +
        • ...
          • +
        • +If the function exits via an exception, lock.unlock() shall be +called prior to exiting the function scope. +
          • +
        +
        +
        + +

        +And make a similar change in p16, and in 30.5.2 [thread.condition.condvarany], +p8 and p13. +

        + + + + + + +
        +

        1223. condition_variable_any lock matching?

        +

        Section: 30.5.2 [thread.condition.condvarany] Status: New + Submitter: Jeffrey Yasskin Opened: 2009-09-30 Last modified: 2009-09-30

        +

        View other active issues in [thread.condition.condvarany].

        +

        View all other issues in [thread.condition.condvarany].

        +

        View all issues with New status.

        +

        Discussion:

        +

        +For condition_variable_any, must all lock arguments to concurrent wait calls +"match" in some way, similar to the requirement in +30.5.1 [thread.condition.condvar] that lock.mutex() returns the same +value for each of the lock arguments supplied by all concurrently +waiting threads (via wait or timed_wait)? +

        + + + +

        Proposed resolution:

        + + + + + +
        +

        1224. condition_variable_any support for recursive mutexes?

        +

        Section: 30.5.2 [thread.condition.condvarany] Status: New + Submitter: Jeffrey Yasskin Opened: 2009-09-30 Last modified: 2009-09-30

        +

        View other active issues in [thread.condition.condvarany].

        +

        View all other issues in [thread.condition.condvarany].

        +

        View all issues with New status.

        +

        Discussion:

        +

        +For condition_variable_any, are recursive mutexes allowed? (I think "no") +

        + + + +

        Proposed resolution:

        + + + + + +
        +

        1225. C++0x result_of issue

        +

        Section: 20.7.4 [func.ret] Status: New + Submitter: Sebastian Gesemann Opened: 2009-10-05 Last modified: 2009-10-17

        +

        View all other issues in [func.ret].

        +

        View all issues with New status.

        +

        Discussion:

        +

        +I think the text about std::result_of could be a little more precise. +Quoting from +N2960... +

        + +
        +

        +20.7.4 [func.ret] Function object return types +

        + +
        template<class> class result_of;
+
+template<class Fn, class... ArgTypes>
+class result_of<Fn(ArgTypes...)> {
+public:
+  typedef see below type;
+};
+
        + +

        +Given an rvalue fn of type Fn and values t1, t2, +..., tN of types T1, T2, ... TN in ArgTypes +respectivly, the type member is the result type of the +expression fn(t1,t2,...,tN). the values ti are lvalues +when the corresponding type Ti is an lvalue-reference type, and +rvalues otherwise. +

        +
        + +

        +This text doesn't seem to consider lvalue reference types for Fn. +Also, it's not clear whether this class template can be used for +"SFINAE" like std::enable_if. Example: +

        + +
        template<typename Fn, typename... Args>
+typename std::result_of<Fn(Args...)>::type
+apply(Fn && fn, Args && ...args)
+{
+  // Fn may be an lvalue reference, too
+  return std::forward<Fn>(fn)(std::forward<Args>(args)...);
+}
+
        + +

        +Either std::result_of<...> can be instantiated and simply may not have +a typedef "type" (-->SFINAE) or instantiating the class template for +some type combinations will be a "hard" compile-time error. +

        + + +

        Proposed resolution:

        + +

        [ +These changes will require compiler support +]

        + + +

        +Change 20.7.4 [func.ret]: +

        + +
        template<class> class result_of; // undefined
+
+template<class Fn, class... ArgTypes>
+class result_of<Fn(ArgTypes...)> {
+public:
+  typedef see below type;
+};
+
        + +

        +Given an rvalue fn of type Fn and values t1, t2, +..., tN of types T1, T2, ... TN in ArgTypes +respectivly, the type member is the result type of the +expression fn(t1,t2,...,tN). the values ti are lvalues +when the corresponding type Ti is an lvalue-reference type, and +rvalues otherwise. +

        + +

        +The class template result_of shall meet the requirements of a +TransformationTrait: Given the types Fn, T1, T2, ..., TN every +template specialization result_of<Fn(T1,T2,...,TN)> shall define the +member typedef type equivalent to decltype(RE) if and only if +the expression RE +

        + +
        
+value<Fn>() ( value<T1>(), value<T2>(), ... value<TN>()  )
+
        + +

        +would be well-formed. Otherwise, there shall be no member typedef +type defined. +

        + +
        + +

        [ +The value<> helper function is a utility Daniel Krügler +proposed in +N2958. +]

        + + + + + + +
        +

        1226. Incomplete changes of #890

        +

        Section: 30.6.2 [futures.errors] Status: Tentatively Ready + Submitter: Daniel Krügler Opened: 2009-10-05 Last modified: 2009-10-27

        +

        View all issues with Tentatively Ready status.

        +

        Discussion:

        +

        +Defect issue 890 overlooked to adapt the future_category from +30.6.1 [futures.overview] and 30.6.2 [futures.errors]: +

        + +
        extern const error_category* const future_category;
+
        + +

        +which should be similarly transformed into function form. +

        + +

        [ +2009-10-27 Howard: +]

        + + +
        +Moved to Tentatively Ready after 5 positive votes on c++std-lib. +
        + + + +

        Proposed resolution:

        +
          +
        1. +

          +Change in 30.6.1 [futures.overview], header <future> synopsis: +

          + +
          extern const error_category&* const future_category();
+
          +
          2. + +
        2. +

          +Change in 30.6.2 [futures.errors]: +

          + +
          extern const error_category&* const future_category();
+
          + +
          +

          +1- future_category shall point to a statically initialized object +of a type derived from class error_category. +

          +

          +1- Returns: A reference to an object of a type +derived from class error_category. +

          +
          + +
          constexpr error_code make_error_code(future_errc e);
+
          + +
          +3 Returns: error_code(static_cast<int>(e), +*future_category()). +
          + +
          constexpr error_code make_error_condition(future_errc e);
+
          + +
          +4 Returns: error_condition(static_cast<int>(e), +*future_category()). +
          +
          +
          3. +
        + + + + + +
        +

        1227. <bitset> synopsis overspecified

        +

        Section: 20.3.7 [template.bitset] Status: Ready + Submitter: Bo Persson Opened: 2009-10-05 Last modified: 2009-10-26

        +

        View other active issues in [template.bitset].

        +

        View all other issues in [template.bitset].

        +

        View all issues with Ready status.

        +

        Discussion:

        +

        +The resolutions to some library defect reports, like 1178 +requires that #includes in each synopsis should be taken +literally. This means that the <bitset> header now +must include <stdexcept>, even though none of the +exceptions are mentioned in the <bitset> header. +

        +

        +Many other classes are required to throw exceptions like +invalid_argument and out_of_range, without explicitly +including <stdexcept> in their synopsis. It is totally +possible for implementations to throw the needed exceptions from utility +functions, whose implementations are not visible in the headers. +

        +

        +I propose that <stdexcept> is removed from the +<bitset> header. +

        + +

        [ +2009-10 Santa Cruz: +]

        + + +
        +Moved to Ready. +
        + + + +

        Proposed resolution:

        +

        +Change 20.3.7 [template.bitset]: +

        + +
        #include <cstddef>        // for size_t
+#include <string>
+#include <stdexcept>      // for invalid_argument,
+                          // out_of_range, overflow_error
+#include <iosfwd>         // for istream, ostream
+namespace std {
+...
+
        + + + + + +
        +

        1228. User-specialized nothrow type traits

        +

        Section: 20.6.4.3 [meta.unary.prop] Status: Open + Submitter: Alisdair Meredith Opened: 2009-10-07 Last modified: 2009-10-26

        +

        View other active issues in [meta.unary.prop].

        +

        View all other issues in [meta.unary.prop].

        +

        View all issues with Open status.

        +

        Discussion:

        +

        +According to p1 20.6.2 [meta.type.synop]: +

        + +
        +The behavior of a program that adds specializations for any of the class +templates defined in this subclause is undefined unless otherwise +specified. +
        + +

        +I believe we should 'otherwise specify' for the nothrow traits, are +these are exactly the use cases where the end user actually has more +information than the compiler. +

        + +

        [ +2009-10 Santa Cruz: +]

        + + +
        +Moved to Open. Definitely need to give the users the ability to ensure +that the traits give the right answers. Unsure we want to give them the +ability to say this in more than one way. Believes the noexcept proposal +already gives this. +
        + + + +

        Proposed resolution:

        +

        +Add the following comment: +

        + +
        +user specialization permitted to derive from std::true_type when the +operation is known not to throw. +
        + +

        +to the following traits in 20.6.4.3 [meta.unary.prop] Table 43 Type +property predicates. +

        + +

        [ +This may require a new Comments column +]

        + + +
        has_nothrow_default_constructor
+has_nothrow_copy_constructor
+has_nothrow_assign
+
        + + + + + +
        +

        1231. weak_ptr comparisons incompletely resolved

        +

        Section: 20.8.15.3.5 [util.smartptr.weak.obs] Status: Tentatively Ready + Submitter: Daniel Krügler Opened: 2009-10-10 Last modified: 2009-11-06

        +

        View all issues with Tentatively Ready status.

        +

        Discussion:

        +

        +The +n2637 +paper suggested several updates of the ordering semantics of +shared_ptr +and weak_ptr, among those the explicit comparison operators of weak_ptr were +removed/deleted, instead a corresponding functor owner_less was added. +The problem +is that +n2637 +did not clearly enough specify, how the previous wording +parts describing +the comparison semantics of weak_ptr should be removed. +

        + +

        [ +2009-11-06 Howard adds: +]

        + + +
        +Moved to Tentatively Ready after 5 positive votes on c++std-lib. +
        + + + +

        Proposed resolution:

        +
          +
        1. +

          +Change 20.8.15.3 [util.smartptr.weak]/2 as described, the intention is to fix +the now no longer valid +requirement that weak_ptr is LessComparable [Note the deleted comma]: +

          + +
          +Specializations of weak_ptr shall be CopyConstructible, +and CopyAssignable, +and LessThanComparable, allowing their use in standard containers. +
          +
          2. + +
        2. +

          +In 20.8.15.3.5 [util.smartptr.weak.obs] remove the paragraphs 9-11 including prototype: +

          + +
          +template<class T, class U> bool operator<(const weak_ptr<T>& a, const weak_ptr<U>& b); + +

          +Returns: an unspecified value such that +

          +
            +
          • +operator< is a strict weak ordering as described in 25.4; +
            • +
          • +under the equivalence relation defined by operator<, !(a +< b) && !(b < a), two weak_ptr instances are +equivalent if and only if they share ownership or are both empty. +
            • +
          + +

          +Throws: nothing. +

          + +

          +[Note: Allows weak_ptr objects to be used as keys in associative +containers. — end note] +

          +
          +
          3. +
        + + + + + +
        +

        1233. Missing unique_ptr signatures in synopsis

        +

        Section: 20.8 [memory] Status: Tentatively NAD Editorial + Submitter: Daniel Krügler Opened: 2009-10-11 Last modified: 2009-11-04

        +

        View all other issues in [memory].

        +

        View all issues with Tentatively NAD Editorial status.

        +

        Discussion:

        +

        +Related to 296. Some unique_ptr signatures are missing +from the synopsis in 20.8 [memory]. +

        + +

        [ +2009-11-04 Howard adds: +]

        + + +
        +Moved to Tentatively NAD Editorial. The editor has adopted the fix. +
        + + +

        Proposed resolution:

        +

        +Add in 20.8 [memory], Header <memory> synopsis +missing declarations as shown below: +

        + +
        // 20.8.11 Class unique_ptr:
+template <class X> class default_delete;
+template<class T> struct default_delete<T[]>;
+template <class X, class D = default_delete<T>> class unique_ptr;
+template<class T, class D> class unique_ptr<T[], D>;
+
+template<class T, class D> void swap(unique_ptr<T, D>& x, unique_ptr<T, D>& y);
+
+template<class T1, class D1, class T2, class D2>
+bool operator==(const unique_ptr<T1, D1>& x, const unique_ptr<T2, D2>& y);
+template<class T1, class D1, class T2, class D2>
+bool operator!=(const unique_ptr<T1, D1>& x, const unique_ptr<T2, D2>& y);
+template<class T1, class D1, class T2, class D2>
+bool operator<(const unique_ptr<T1, D1>& x, const unique_ptr<T2, D2>& y);
+template<class T1, class D1, class T2, class D2>
+bool operator<=(const unique_ptr<T1, D1>& x, const unique_ptr<T2, D2>& y);
+template<class T1, class D1, class T2, class D2>
+bool operator>(const unique_ptr<T1, D1>& x, const unique_ptr<T2, D2>& y);
+template<class T1, class D1, class T2, class D2>
+bool operator>=(const unique_ptr<T1, D1>& x, const unique_ptr<T2, D2>& y);
+
        + + + + + +
        +

        1234. "Do the right thing" and NULL

        +

        Section: 23.2.3 [sequence.reqmts] Status: New + Submitter: Matt Austern Opened: 2009-10-09 Last modified: 2009-10-13

        +

        View other active issues in [sequence.reqmts].

        +

        View all other issues in [sequence.reqmts].

        +

        View all issues with New status.

        +

        Discussion:

        +

        +On g++ 4.2.4 (x86_64-linux-gnu), the following file gives a compile +error: +

        + +
        #include <vector>
+void foo() { std::vector<int*> v(500l, NULL); }
+
        + +

        +Is this supposed to work? +

        + +

        +The issue: if NULL happens to be defined as 0l, this is an invocation of +the constructor with two arguments of the same integral type. +23.2.3 [sequence.reqmts]/11 says that this will behave as if the the +overloaded constructor +

        + +
        X(size_type, const value_type& = value_type(),
+  const allocator_type& = allocator_type())
+
        + +

        +were called instead, with the arguments +static_cast<size_type>(first), last and +alloc, respectively. However, it does not say whether this +actually means invoking that constructor with the exact textual form of +the arguments as supplied by the user, or whether the standard permits +an implementation to invoke that constructor with variables of the same +type and value as what the user passed in. In most cases this is a +distinction without a difference. In this particular case it does make a +difference, since one of those things is a null pointer constant and the +other is not. +

        + +

        +Note that an implementation based on forwarding functions will use the +latter interpretation. +

        + + +

        Proposed resolution:

        + + + + + +
        +

        1237. Constrained error_code/error_condition members

        +

        Section: 19.5 [syserr] Status: Ready + Submitter: Daniel Krügler Opened: 2009-10-14 Last modified: 2009-10-26

        +

        View all other issues in [syserr].

        +

        View all issues with Ready status.

        +

        Discussion:

        +

        +I'm just reflecting on the now SFINAE-constrained constructors +and assignment operators of error_code and error_condition: +

        +

        +These are the only library components that are pro-actively +announcing that they are using std::enable_if as constraining tool, +which has IMO several disadvantages: +

        + +
          +
        1. +

          +With the availability of template default arguments and +decltype, using enable_if in C++0x standard library, seems +unnecessary restricting implementation freedom. E.g. there +should be not need for a useless specification of a dummy +default function argument, which only confuses the reader. +A more reasonable implementation could e.g. be +

          + +
          template <class ErrorCodeEnum
+ class = typename enable_if<is_error_code_enum<ErrorCodeEnum>::value>::type>
+error_code(ErrorCodeEnum e);
+
          + +

          +As currently specified, the function signatures are so unreadable, +that errors quite easily happen, see e.g. 1229. +

          +
          2. + +
        2. +

          +We have a lot of constrained functions in other places, that +now have a standard phrase that is easily understandable: +

          + +
          +Remarks: This constructor/function shall participate in overload +resolution if and only if X. +
          + +

          +where X describes the condition. Why should these components deviate? +

          +
          3. + +
        3. +

          +If enable_if would not be explicitly specified, the standard library +is much better prepared for the future. It would also be possible, that +libraries with partial support for not-yet-standard-concepts could provide +a much better diagnostic as is possible with enable_if. This again +would allow for experimental concept implementations in the wild, +which as a result would make concept standardization a much more +natural thing, similar to the way as templates were standardized +in C++. +

          + +

          +In summary: I consider it as a library defect that error_code and +error_condition explicitly require a dependency to enable_if and +do limit implementation freedom and I volunteer to prepare a +corresponding resolution. +

          +
          4. +
        + +

        [ +2009-10-18 Beman adds: +]

        + + +
        +I support this proposed resolution, and thank Daniel for writing it up. +
        + +

        [ +2009-10 Santa Cruz: +]

        + + +
        +Moved to Ready. +
        + + + +

        Proposed resolution:

        +

        [ +Should this resolution be accepted, I recommend to resolve 1229 as NAD +]

        + + +
          +
        1. +

          +In 19.5.2.1 [syserr.errcode.overview]/1, class error_code, +change as indicated: +

          + +
          // 19.5.2.2 constructors:
+error_code();
+error_code(int val, const error_category& cat);
+template <class ErrorCodeEnum>
+  error_code(ErrorCodeEnum e,
+    typename enable_if<is_error_code_enum<ErrorCodeEnum>::value>::type * = 0);
+
+// 19.5.2.3 modifiers:
+void assign(int val, const error_category& cat);
+template <class ErrorCodeEnum>
+  typename enable_if<is_error_code_enum<ErrorCodeEnum>::value>::typeerror_code&
+    operator=(ErrorCodeEnum e);
+void clear();
+
          +
          2. + +
        2. +

          +Change 19.5.2.2 [syserr.errcode.constructors] around the prototype before p. 7: +

          + +
          template <class ErrorCodeEnum>
+error_code(ErrorCodeEnum e,
+  typename enable_if<is_error_code_enum<ErrorCodeEnum>::value>::type * = 0);
+
          +
          +

          +Remarks: This constructor shall not participate in overload +resolution, unless +is_error_code_enum<ErrorCodeEnum>::value == true. +

          +
          +
          +
          3. + +
        3. +

          +Change 19.5.2.3 [syserr.errcode.modifiers] around the prototype before p. 3: +

          + +
          template <class ErrorCodeEnum>
+  typename enable_if<is_error_code_enum<ErrorCodeEnum>::value>::typeerror_code&
+    operator=(ErrorCodeEnum e);
+
          + +
          +Remarks: This operator shall not participate in overload resolution, unless +is_error_code_enum<ErrorCodeEnum>::value == true. +
          +
          +
          4. + +
        4. +

          +In 19.5.3.1 [syserr.errcondition.overview]/1, class error_condition, change +as indicated: +

          + +
          // 19.5.3.2 constructors:
+error_condition();
+error_condition(int val, const error_category& cat);
+template <class ErrorConditionEnum>
+  error_condition(ErrorConditionEnum e,
+    typename enable_if<is_error_condition_enum<ErrorConditionEnum>::type* = 0);
+
+// 19.5.3.3 modifiers:
+void assign(int val, const error_category& cat);
+template<typenameclass ErrorConditionEnum>
+  typename enable_if<is_error_condition_enum<ErrorConditionEnum>, error_code>::typeerror_condition &
+    operator=( ErrorConditionEnum e );
+void clear();
+
          +
          5. + +
        5. +

          +Change 19.5.3.2 [syserr.errcondition.constructors] around the +prototype before p. 7: +

          + +
          template <class ErrorConditionEnum>
+  error_condition(ErrorConditionEnum e,
+    typename enable_if<is_error_condition_enum<ErrorConditionEnum>::value>::type* = 0);
+
          +
          +Remarks: This constructor shall not participate in overload +resolution, unless +is_error_condition_enum<ErrorConditionEnum>::value == true. +
          +
          +
          6. + +
        6. +

          +Change 19.5.3.3 [syserr.errcondition.modifiers] around the +prototype before p. 3: +

          + +
          template <class ErrorConditionEnum>
+  typename enable_if<is_error_condition_enum<ErrorConditionEnum>::value>::typeerror_condition&
+    operator=(ErrorConditionEnum e);
+
          + +
          +

          +Remarks: This operator shall not participate in overload resolution, unless +is_error_condition_enum<ErrorConditionEnum>::value == true. +

          + +

          +Postcondition: *this == make_error_condition(e). +

          + +

          +Returns: *this +

          +
          +
          + +
          7. +
        + + + + + + +
        +

        1238. defining algorithms taking iterator for range

        +

        Section: 25 [algorithms] Status: Tentatively NAD Future + Submitter: Alisdair Meredith Opened: 2009-10-15 Last modified: 2009-11-03

        +

        View other active issues in [algorithms].

        +

        View all other issues in [algorithms].

        +

        View all issues with Tentatively NAD Future status.

        +

        Discussion:

        +

        +The library has many algorithms that take a source range represented by +a pair of iterators, and the start of some second sequence given by a +single iterator. Internally, these algorithms will produce undefined +behaviour if the second 'range' is not as large as the input range, but +none of the algorithms spell this out in Requires clauses, and there is +no catch-all wording to cover this in clause 17 or the front matter of +25. +

        + +

        +There was an attempt to provide such wording in paper +n2944 +but this +seems incidental to the focus of the paper, and getting the wording of +this issue right seems substantially more difficult than the simple +approach taken in that paper. Such wording will be removed from an +updated paper, and hopefully tracked via the LWG issues list instead. +

        + +

        +It seems there are several classes of problems here and finding wording +to solve all in one paragraph could be too much. I suspect we need +several overlapping requirements that should cover the desired range of +behaviours. +

        + +

        +Motivating examples: +

        + +

        +A good initial example is the swap_ranges algorithm. Here there is a +clear requirement that first2 refers to the start of a valid range at +least as long as the range [first1, last1). n2944 tries to solve this +by positing a hypothetical last2 iterator that is implied by the +signature, and requires distance(first2,last2) < distance(first1,last1). + This mostly works, although I am uncomfortable assuming that last2 is +clearly defined and well known without any description of how to obtain +it (and I have no idea how to write that). +

        + +

        +A second motivating example might be the copy algorithm. Specifically, +let us image a call like: +

        + +
        copy(istream_iterator<int>(is),istream_iterator(),ostream_iterator<int>(os));
+
        + +

        +In this case, our input iterators are literally simple InputIterators, +and the destination is a simple OutputIterator. In neither case am I +happy referring to std::distance, in fact it is not possible for the +ostream_iterator at all as it does not meet the requirements. However, +any wording we provide must cover both cases. Perhaps we might deduce +last2 == ostream_iterator<int>{}, but that might not always be valid for +user-defined iterator types. I can well imagine an 'infinite range' +that writes to /dev/null and has no meaningful last2. +

        + +

        +The motivating example in n2944 is std::equal, and that seems to fall somewhere between the +two. +

        + +

        +Outlying examples might be partition_copy that takes two output +iterators, and the _n algorithms where a range is specified by a +specific number of iterations, rather than traditional iterator pair. +We should also not accidentally apply inappropriate constraints to +std::rotate which takes a third iterator that is not intended to be a +separate range at all. +

        + +

        +I suspect we want some wording similar to: +

        + +
        +For algorithms that operate on ranges where the end iterator of the +second range is not specified, the second range shall contain at least +as many elements as the first. +
        + +

        +I don't think this quite captures the intent yet though. I am not sure +if 'range' is the right term here rather than sequence. More awkwardly, +I am not convinced we can describe an Output sequence such as produce by +an ostream_iterator as "containing elements", at least not as a +precondition to the call before they have been written. +

        + +

        +Another idea was to describe require that the trailing iterator support +at least distance(input range) applications of operator++ and may be +written through the same number of times if a mutable/output iterator. +

        + +

        +We might also consider handling the case of an output range vs. an input +range in separate paragraphs, if that simplifies how we describe some of +these constraints. +

        + +

        [ +2009-11-03 Howard adds: +]

        + + +
        +Moved to Tentatively NAD Future after 5 positive votes on c++std-lib. +
        + + +

        Proposed resolution:

        + + + + + +
        +

        1239. Defect report

        +

        Section: 20.6.4.3 [meta.unary.prop] Status: Tentatively NAD Editorial + Submitter: David Abrahams Opened: 2009-10-16 Last modified: 2009-10-26

        +

        View other active issues in [meta.unary.prop].

        +

        View all other issues in [meta.unary.prop].

        +

        View all issues with Tentatively NAD Editorial status.

        +

        Discussion:

        +

        +Table 43 defines a number of traits that yield true for arrays of class +types with the trait's property, but not arrays of other types with that +property. For example, has_trivial_default_constructor: +

        + +
        +T is a trivial type (3.9) or a class type with a trivial default +constructor (12.1) or an array of such a class type. +
        + +

        [ +2009-10 post-Santa Cruz: +]

        + + +
        +

        +An array of a trivial type is a trivial type. +

        +

        +Mark as Tentatively NAD Editorial. The wording is OK as is, +since an array of a trivial type is a trivial type, but the wording as +proposed might be clearer. +

        +
        + + + +

        Proposed resolution:

        +

        +Change all the traits in question following this pattern: +

        + +
        +T is a trivial type (3.9) or a class type with a trivial default + constructor (12.1), or an array of such a class type. +
        + +

        +i.e., add a comma and delete a "class." +

        + + + + + +
        +

        1240. Deleted comparison functions of std::function not needed

        +

        Section: 20.7.15.2 [func.wrap.func] Status: New + Submitter: Daniel Krügler Opened: 2009-10-18 Last modified: 2009-10-19

        +

        View all other issues in [func.wrap.func].

        +

        View all issues with New status.

        +

        Discussion:

        +

        +The class template std::function contains the following member +declarations: +

        + +
        // deleted overloads close possible hole in the type system
+template<class R2, class... ArgTypes2>
+  bool operator==(const function<R2(ArgTypes2...)>&) = delete;
+template<class R2, class... ArgTypes2>
+  bool operator!=(const function<R2(ArgTypes2...)>&) = delete;
+
        + +

        +The leading comment here is part of the history of std::function, which +was introduced with N1402. +During that time no explicit conversion functions existed, and the +"safe-bool" idiom (based on pointers-to-member) was a popular +technique. The only disadvantage of this idiom was that given two +objects f1 and f2 of type std::function the expression +

        + +
        f1 == f2;
+
        + +

        +was well-formed, just because the built-in operator== for pointer to member +was considered after a single user-defined conversion. To fix this, an +overload set of undefined comparison functions was added, +such that overload resolution would prefer those ending up in a linkage error. +The new language facility of deleted functions provided a much better +diagnostic mechanism to fix this issue. +

        + +

        +The central point of this issue is, that with the replacement of the +safe-bool idiom by explicit conversion to bool the original "hole in the +type system" does no longer exist and therefore the comment is wrong and +the superfluous function definitions should be removed as well. An +explicit conversion function is considered in direct-initialization +situations only, which indirectly contain the so-called "contextual +conversion to bool" (4 [conv]/3). These conversions are not considered for +== or != as defined by the core language. +

        + + +

        Proposed resolution:

        +

        +In 20.7.15.2 [func.wrap.func]/1, class function change as indicated: +

        + +
        // 20.7.15.2.3, function capacity:
+explicit operator bool() const;
+
+// deleted overloads close possible hole in the type system
+template<class R2, class... ArgTypes2>
+  bool operator==(const function<R2(ArgTypes2...)>&) = delete;
+template<class R2, class... ArgTypes2>
+  bool operator!=(const function<R2(ArgTypes2...)>&) = delete;
+
        + + + + + +
        +

        1241. unique_copy needs to require EquivalenceRelation

        +

        Section: 25.3.9 [alg.unique] Status: Tentatively Ready + Submitter: Daniel Krügler Opened: 2009-10-17 Last modified: 2009-10-31

        +

        View all other issues in [alg.unique].

        +

        View all issues with Tentatively Ready status.

        +

        Discussion:

        +

        +A lot of fixes were silently applied during concept-time and we should +not lose them again. The Requires clause of 25.3.9 [alg.unique]/5 +doesn't mention that == and the predicate need to satisfy an +EquivalenceRelation, as it is correctly said for +unique. This was intentionally fixed during conceptification, +were we had: +

        + +
        template<InputIterator InIter, class OutIter>
+  requires OutputIterator<OutIter, RvalueOf<InIter::value_type>::type>
+        && EqualityComparable<InIter::value_type>
+        && HasAssign<InIter::value_type, InIter::reference>
+        && Constructible<InIter::value_type, InIter::reference>
+  OutIter unique_copy(InIter first, InIter last, OutIter result);
+
+template<InputIterator InIter, class OutIter,
+         EquivalenceRelation<auto, InIter::value_type> Pred>
+  requires OutputIterator<OutIter, RvalueOf<InIter::value_type>::type>
+        && HasAssign<InIter::value_type, InIter::reference>
+        && Constructible<InIter::value_type, InIter::reference>
+        && CopyConstructible<Pred>
+  OutIter unique_copy(InIter first, InIter last, OutIter result, Pred pred);
+
        + +

        +Note that EqualityComparable implied an equivalence relation. +

        + +

        [ +N.B. adjacent_find was also specified to require +EquivalenceRelation, but that was considered as a defect in +concepts, see 1000 +]

        + + +

        [ +2009-10-31 Howard adds: +]

        + + +
        +Moved to Tentatively Ready after 5 positive votes on c++std-lib. +
        + + + +

        Proposed resolution:

        +

        +Change 25.3.9 [alg.unique]/5 as indicated: +

        + +
        template<class InputIterator, class OutputIterator>
+  OutputIterator
+    unique_copy(InputIterator first, InputIterator last, OutputIterator result);
+
+template<class InputIterator, class OutputIterator, class BinaryPredicate>
+  OutputIterator
+    unique_copy(InputIterator first, InputIterator last,
+                OutputIterator result, BinaryPredicate pred);
+
        +
        +Requires: The comparison function shall be an equivalence +relation. The ranges [first,last) and +[result,result+(last-first)) shall not overlap. The expression +*result = *first shall be valid. If neither +InputIterator nor OutputIterator meets the +requirements of forward iterator then the value type of +InputIterator shall be CopyConstructible (34) and +CopyAssignable (table 36). Otherwise CopyConstructible +is not required. +
        +
        + + + + + +
        +

        1244. wait_*() in *future for synchronous functions

        +

        Section: 30.6 [futures] Status: New + Submitter: Detlef Vollmann Opened: 2009-10-22 Last modified: 2009-10-23

        +

        View all other issues in [futures].

        +

        View all issues with New status.

        +

        Discussion:

        +

        +With the addition of async(), a future might be +associated with a function that is not running in a different thread but +is stored to by run synchronously on the get() call. It's not +clear what the wait() functions should do in this case. +

        + +

        +Suggested resolution: +

        + +

        +Throw an exception. +

        + + +

        Proposed resolution:

        + + + + + +
        +

        1245. std::hash<string> & co

        +

        Section: 20.7.16 [unord.hash] Status: New + Submitter: Paolo Carlini Opened: 2009-10-22 Last modified: 2009-10-25

        +

        View other active issues in [unord.hash].

        +

        View all other issues in [unord.hash].

        +

        View all issues with New status.

        +

        Discussion:

        +

        +In 20.7.16 [unord.hash], operator() is specified as +taking the argument by value. Moreover, it is said that operator() shall +not throw exceptions. +

        + +

        +However, for the specializations for class types, like string, wstring, +etc, the former requirement seems suboptimal from the performance point +of view (a specific PR has been filed about this in the GCC Bugzilla) +and, together with the latter requirement, hard if not impossible to +fulfill. It looks like pass by const reference should be allowed in such +cases. +

        + + +

        Proposed resolution:

        +

        +Add to 20.7.16 [unord.hash]/2: +

        + +
        +
        namespace std {
+  template <class T>
+  struct hash : public std::unary_function<T, std::size_t> {
+    std::size_t operator()(T val) const;
+  };
+}
+
        + +

        +The return value of operator() is unspecified, except that +equal arguments shall yield the same result. operator() shall +not throw exceptions. It is also unspecified whether +operator() of std::hash specializations for class +types takes its argument by value or const reference. +

        +
        + + + + + +
        +

        1246. vector::resize() missing efficiency guarantee

        +

        Section: 23.3.6.2 [vector.capacity] Status: New + Submitter: David Abrahams Opened: 2009-10-24 Last modified: 2009-10-25

        +

        View all other issues in [vector.capacity].

        +

        View all issues with New status.

        +

        Discussion:

        +

        +If v is a vector, I think repeated calls to +v.resize( v.size() + 1 ) should be amortized O(1), but it's not +clear that's true from the text of the standard: +

        + +
        void resize(size_type sz);
+
        +
        +Effects: If sz < size(), equivalent to erase(begin() + sz, end());. If +size() < sz, appends sz - size() default constructed elements to the +sequence. +
        +
        + +

        +Seems to me if we used push_back instead of appends, we might be giving +the guarantee I'd like. Thoughts? +

        + + +

        Proposed resolution:

        +

        +In 23.3.6.2 [vector.capacity]/10, change +

        + +
        void resize(size_type sz);
+
        +
        +Effects: If sz < size(), equivalent to erase(begin() + sz, end());. If +size() < sz, appends sz - size() default constructed elements to the +sequence +equivalent to sz - size() consecutive evaluations of push_back(T()). +
        +
        + + + + + + +
        +

        1247. auto_ptr is overspecified

        +

        Section: D.10.1 [auto.ptr] Status: Review + Submitter: Alisdair Meredith Opened: 2009-10-24 Last modified: 2009-11-06

        +

        View all other issues in [auto.ptr].

        +

        View all issues with Review status.

        +

        Discussion:

        +

        +This issue is extracted as the ongoing point-of-interest from earlier +issue 463. +

        + +

        +auto_ptr is overspecified as the auto_ptr_ref +implementation detail is formally specified, and the technique is +observable so workarounds for compiler defects can cause a working +implementation of the primary auto_ptr template become +non-conforming. +

        + +

        +auto_ptr_ref is a documentation aid to describe a possible +mechanism to implement the class. It should be marked exposition only, +as per similar classes, e.g., istreambuf_iterator::proxy +

        + +

        [ +2009-10-25 Daniel adds: +]

        + + +
        +

        +I wonder, whether the revised wording shouldn't be as straight as +for istream_buf by adding one further sentence: +

        + +
        +An implementation is permitted to provide equivalent functionality without +providing a class with this name. +
        +
        + +

        [ +2009-11-06 Alisdair adds Daniel's suggestion to the proposed wording. +]

        + + +

        [ +2009-11-06 Howard moves issue to Review. +]

        + + + + +

        Proposed resolution:

        +

        +Add the term "exposition only" in the following two places: +

        + +

        +Ammend D.10.1 [auto.ptr]p2: +

        + +
        +

        +The exposition only class Ttemplate auto_ptr_ref +holds a reference to an auto_ptr. It is used by the +auto_ptr conversions to allow auto_ptr objects to be +passed to and returned from functions. +An implementation is permitted to provide equivalent functionality +without providing a class with this name. +

        + +
        namespace std {
+ template <class Y> struct auto_ptr_ref { }; // exposition only
+
        +
        + + + + + +
        +

        1249. basic_ios default ctor

        +

        Section: 27.5.4.1 [basic.ios.cons] Status: New + Submitter: Martin Sebor Opened: 2009-10-25 Last modified: 2009-10-26

        +

        View all other issues in [basic.ios.cons].

        +

        View all issues with New status.

        +

        Discussion:

        +

        +The basic_ios default ctor is required to leave the objects members +uninitialized (see below). The paragraph says the object must be +initialized by calling basic_ios::init() before it's destroyed by +I can't find a requirement that it be initialized before calling +any of the class other member functions. Am I not looking in the +right place or that an issue? +

        + +

        [ +2009-10-25 Daniel adds: +]

        + + +
        +

        +I agree, that your wording makes that clearer, but suggest to write +

        + +
        +... calling basic_ios::init() before ... +
        + +

        +Doing so, I recommend to adapt that of ios_base(); as well, where +we have: +

        + +
        +Effects: Each ios_base member has an indeterminate value +after construction. These members shall be initialized by calling +basic_ios::init. If an ios_base object is destroyed +before these initializations have taken place, the behavior is +undefined. +
        +
        + + + +

        Proposed resolution:

        +

        +Change 27.5.2.7 [ios.base.cons] p1: +

        + +
        ios_base();
+
        +
        +Effects: Each ios_base member has an indeterminate value +after construction. These The object's members shall be initialized by calling +basic_ios::init before the object's first use or before + it is destroyed, whichever comes first; otherwise the behavior + is undefined.. If an ios_base object is destroyed +before these initializations have taken place, the behavior is +undefined. +
        +
        + +

        +Change 27.5.4.1 [basic.ios.cons] p2: +

        + +
        basic_ios();
+
        +
        +Effects: Constructs an object of class basic_ios +(27.5.2.7) leaving its member objects uninitialized. The object shall be +initialized by calling its +basic_ios::init before its first +use or before it is destroyed, whichever comes first; otherwise the +behavior is undefined. member function. If it is destroyed +before it has been initialized the behavior is undefined. +
        +
        + + + + + +
        +

        1250. <bitset> still overspecified

        +

        Section: 20.3.7 [template.bitset] Status: New + Submitter: Martin Sebor Opened: 2009-10-29 Last modified: 2009-10-29

        +

        View other active issues in [template.bitset].

        +

        View all other issues in [template.bitset].

        +

        View all issues with New status.

        +

        Discussion:

        +

        +Issue 1227 — <bitset> synopsis overspecified makes the observation +that std::bitset, and in fact the whole library, may be implemented +without needing to #include <stdexcept> in any library header. The +proposed resolution removes the #include <stdexcept> directive from +the header. +

        + +

        +I'd like to add that the <bitset> header (as well as the rest of +the library) has also been implemented without #including the +<cstddef> header in any library header. In the case of std::bitset, +the template is fully usable (i.e., it may be instantiated and all +its member functions may be used) without ever mentioning size_t. +In addition, just like no library header except for <bitset> +#includes <stdexcept> in its synopsis, no header but <bitset> +#includes <cstddef> either. +

        + +

        +Thus I suggest that the #include <cstddef> directive be similarly +removed from the synopsis of <bitset>. +

        + + +

        Proposed resolution:

        +

        +Change 20.3.7 [template.bitset]: +

        + +
        #include <cstddef>        // for size_t
+#include <string>
+#include <iosfwd>         // for istream, ostream
+namespace std {
+...
+
        + + + + + +
        +

        1251. move constructing basic_stringbuf

        +

        Section: 27.8.1.1 [stringbuf.cons] Status: New + Submitter: Martin Sebor Opened: 2009-10-29 Last modified: 2009-10-29

        +

        View all other issues in [stringbuf.cons].

        +

        View all issues with New status.

        +

        Discussion:

        +

        +I just came across issue 1204 -- Global permission to move, which +seems to address the concern raised by the example in c++std-lib-25030. +

        +

        +IIUC, the example violates the permission to assume that arguments +bound to rvalue references are unnamed temporaries granted to +implementations by the resolution of issue 1204 - Global permission +to move. +

        + +

        +I.e., the ostringstream(ostringstream &&rhs) ctor can leave the rhs +pointers pointing to the newly constructed object's buffer just as +long as the dtor doesn't change or invalidate the buffer. The caller +may not make any assumptions about rhs after the move beyond it being +safe to destroy or reassign. +

        + +

        +So unless I misunderstood something, I still think the basic_stringbuf +move ctor is overspecified. Specifically, I think the third sentence +in the Effects clause and the last 6 bullets in the Postconditions +clause can, and IMO should, be stricken. +

        + + +

        Proposed resolution:

        +

        +Strike from 27.8.1.1 [stringbuf.cons]: +

        + +
        basic_stringbuf(basic_stringbuf&& rhs);
+
        +
        +

        +Effects: Move constructs from the rvalue rhs. It is +implementation-defined whether the sequence pointers in *this +(eback(), gptr(), egptr(), pbase(), +pptr(), epptr()) obtain the values which rhs +had. Whether they do or not, *this and rhs reference +separate buffers (if any at all) after the construction. The openmode, +locale and any other state of rhs is also copied. +

        + +

        +Postconditions: Let rhs_p refer to the state of +rhs just prior to this construction and let rhs_a +referto the state of rhs just after this construction. +

        +
          +
        • +str() == rhs_p.str() +
          • +
        • +gptr() - eback() == rhs_p.gptr() - rhs_p.eback() +
          • +
        • +egptr() - eback() == rhs_p.egptr() - rhs_p.eback() +
          • +
        • +pptr() - pbase() == rhs_p.pptr() - rhs_p.pbase() +
          • +
        • +epptr() - pbase() == rhs_p.epptr() - rhs_p.pbase() +
          • +
        • +if (eback()) eback() != rhs_a.eback() +
          • +
        • +if (gptr()) gptr() != rhs_a.gptr() +
          • +
        • +if (egptr()) egptr() != rhs_a.egptr() +
          • +
        • +if (pbase()) pbase() != rhs_a.pbase() +
          • +
        • +if (pptr()) pptr() != rhs_a.pptr() +
          • +
        • +if (epptr()) epptr() != rhs_a.epptr() +
          • +
        +
        +
        + + + + + + +
        +

        1252. wbuffer_convert::state_type inconsistency

        +

        Section: 22.3.3.2.3 [conversions.buffer] Status: New + Submitter: Bo Persson Opened: 2009-10-21 Last modified: 2009-10-31

        +

        View all issues with New status.

        +

        Discussion:

        +

        +The synopisis for wbuffer_convert 22.3.3.2.3 [conversions.buffer]/2 contains +

        + +
        typedef typename Tr::state_type   state_type; 
+
        + +

        +making state_type a synonym for (possibly) some +char_traits<x>::state_type. +

        + +

        +However, in paragraph 9 of the same section, we have +

        + +
        typedef typename Codecvt::state_type state_type;
+
        + +
        +The type shall be a synonym for Codecvt::state_type. +
        +
        + +

        +From what I can see, it might be hard to implement +wbuffer_convert if the types were not both +std::mbstate_t, but I cannot find a requirement that they must +be the same type. +

        + + +

        Proposed resolution:

        + + + + + +
        +

        1253. invalidation of iterators and emplace vs. insert inconsistence in assoc. containers

        +

        Section: 23.2.4 [associative.reqmts] Status: New + Submitter: Boris Dušek Opened: 2009-10-24 Last modified: 2009-10-31

        +

        View other active issues in [associative.reqmts].

        +

        View all other issues in [associative.reqmts].

        +

        View all issues with New status.

        +

        Discussion:

        +

        +In the latest published draft +N2960, +section 23.2.4 [associative.reqmts], paragraph 8, it is specifies +that that insert does not invalidate any iterators. As per +23.2.1 [container.requirements.general], paragraph 12, this holds +true not only for insert, but emplace as well. This +gives the insert member a special treatment w.r.t. +emplace member in 23.2.4 [associative.reqmts], par. 8, +since both modify the container. For the sake of consistency, in 23.2.4 [associative.reqmts], par. 8: either reference to +insert should be removed (i.e. count on 23.2.1 [container.requirements.general], par. 12), or reference to +emplace be added (i.e. mention all members of assoc. containers +that modify it). +

        + + +

        Proposed resolution:

        +

        +

        + + + + + +
        +

        1254. Misleading sentence in vector<bool>::flip

        +

        Section: 23.3.7 [vector.bool] Status: New + Submitter: Christopher Jefferson Opened: 2009-11-01 Last modified: 2009-11-01

        +

        View all other issues in [vector.bool].

        +

        View all issues with New status.

        +

        Discussion:

        +

        +The effects of vector<bool>::flip has the line: +

        + +
        +It is unspecified whether the function has any effect on allocated but +unused bits. +
        + +

        +While this is technically true, it is misleading, as any member function +in any standard container may change unused but allocated memory. Users +can never observe such changes as it would also be undefined behaviour +to read such memory. +

        + + +

        Proposed resolution:

        +

        +Strike second sentence from the definition of vector<bool>::flip(), +23.3.7 [vector.bool], paragraph 5. +

        + +
        +Effects: Replaces each element in the container with its complement. +It is unspecified whether the function has any effect on allocated +but unused bits. +
        + + + + + +
        +

        1255. declval should be added to the library

        +

        Section: 20.3 [utility] Status: New + Submitter: Daniel Krügler Opened: 2009-11-03 Last modified: 2009-11-04

        +

        View all issues with New status.

        +

        Discussion:

        +

        +During the Santa Cruz meeting it was decided to split off the provision +of the library utility value() proposed in N2979 +from the concrete request of the +UK 300 +comment. +The provision of a new library component that allows the production of +values in unevaluated expressions is considered as important +to realize constrained templates in C++0x where concepts are not +available. +

        + +

        +The following proposed resolution is an improvement over that suggested in +N2958, +because the proposed component can now be defined without loss of +general usefulness and any use by user-code will make the program ill-formed. +A possible prototype implementation that satisfies the core language +requirements +can be written as: +

        + +
        template<class T>
+  struct declval_protector {
+    static const bool stop = false;
+    static typename std::add_rvalue_reference<T>::type delegate(); // undefined
+  };
+
+template<class T>
+typename std::add_rvalue_reference<T>::type declval() {
+  static_assert(declval_protector<T>::stop, "declval() must not be used!");
+  return declval_protector<T>::delegate();
+}
+
        + +

        +Further-on the earlier suggested name value() has been changed to declval() +after discussions with committee members. +

        + +

        +Finally the suggestion shown below demonstrates that it can simplify +existing standard wording by directly using it in the library +specification, and that it also improves an overlooked corner case for +common_type by adding support for cv void. +

        + + +

        Proposed resolution:

        +

        [ +The following edit assumes that the earlier component identity +has been removed as part of applying the solution of 939, +N2951, +and +N2984. +Note that the proposal does not depend on this application, +but it just simplifies the editorial representation +]

        + + +
          +
        1. +

          +Change 20.3 [utility], header <utility> synopsis +as indicated: +

          + +
          // 20.3.2, forward/move:
+template <class T, class U> T&& forward(U&& u);;
+template <class T> typename remove_reference<T>::type&& move(T&&);
+
+// 20.3.3, declval:
+template <class T> typename add_rvalue_reference<T>::type declval(); // for unused context
+
          +
          2. + +
        2. +

          +Immediately after the current section 20.3.3 [forward] insert a +new section: +

          +

          +20.3.3 Function template declval [declval] +

          +

          +The library provides the function template declval to simplify +the definition of expressions in +unevaluated and unused contexts (3.2 [basic.def.odr], 5 [expr]). The +template parameter T of declval may +be an incomplete type. +

          + +
          template <class T> typename add_rvalue_reference<T>::type declval(); // for unused context
+
          + +
          +

          +Remarks: If this function is used according to 3.2 [basic.def.odr], +the program shall be ill-formed. +

          + +

          +[Example: +

          + +
          
+template<class To, class From>
+decltype(static_cast<To>(declval<From>())) convert(From&&);
+
          + +

          + +declares a function template convert, which does only participate in +overloading, if the type From can be +explicitly casted to type To — end example] +

          +
          + +
          3. + +
        3. +

          +This bullet just makes clear that after applying N2984, the changes in 20.6.4.3 [meta.unary.prop], before +table Type property queries should not use declval, +because the well-formedness requirement of the specification of +is_constructible would become more complicated, because we +would need to make sure that the expression CE is checked in an +unevaluated context. +

          +
          4. + +
        4. +

          +Also 20.6.5 [meta.rel]/4 is not modified similar to the previous bullet, +because with +the stricter requirements of not using declval() the well-formedness condition +would be harder to specify. The following changes are only editorial ones (e.g. +the removal of the duplicate declaration of create()): +

          + +
          +

          +Given the following function prototype: +

          + +
          template <class T>
+  typename add_rvalue_reference<T>::type create();
+
          + +

          +the predicate condition for a template specialization +is_convertible<From, To> shall be satisfied if and only +if the return expression in the following code would be well-formed, +including any +immplicit conversions to the return type of the function: +

          + +
          template <class T>
+typename add_rvalue_reference<T>::type create();
+To test() {
+  return create<From>();
+}
+
          +
          +
          5. + +
        5. +

          +Change the entry in column "Comments" for common_type in Table 51 — +Other transformations (20.6.7 [meta.trans.other]): +

          + +

          [ +NB: This wording change extends the type domain of common_type for cv +void => cv void transformations and thus makes common_type usable for +all binary type combinations that are supported by is_convertible +]

          + + +
          +The member typedef type shall be defined as set out below. All +types in the parameter pack T shall be complete or +(possibly cv-qualified) void. A program may specialize +this trait if at least one template parameter in the specialization is a +user-defined type. [Note: Such specializations are needed when +only explicit conversions are desired among the template arguments. +— end note] +
          +
          6. + +
        6. +

          +Change 20.6.7 [meta.trans.other]/3 as indicated: +

          + +

          [ +NB: This wording change is more than an editorial simplification of +the definition of common_type: It also extends its usefulness for cv +void types as outlined above +]

          + + +
          +

          +The nested typedef common_type::type shall be defined as follows: +

          + +
          +

          +[..] +

          +
          template <class T, class U>
+struct common_type<T, U> {
+private:
+  static T&& __t();
+  static U&& __u();
+public:
+  typedef decltype(true ? __tdeclval<T>() : __udeclval<U>()) type;
+};
+
          +
          +
          +
          7. +
        + + + + + + +
        +

        1256. weak_ptr comparison functions should be removed

        +

        Section: 20.8.15.3 [util.smartptr.weak] Status: New + Submitter: Daniel Krügler Opened: 2009-11-04 Last modified: 2009-11-04

        +

        View all issues with New status.

        +

        Discussion:

        +

        +Additional to the necessary cleanup of the description of the the +weak_ptr component from 20.8.15.3 [util.smartptr.weak] +described in 1231 it turns out that the currently deleted +comparison functions of weak_ptr are not needed at all: There +is no safe-bool conversion from weak_ptr, and it won't silently +chose a conversion to shared_ptr. +

        + + +

        Proposed resolution:

        +

        +Change 20.8.15.3 [util.smartptr.weak]/1 as indicated: +

        + +
        namespace std {
+template<class T> class weak_ptr {
+public:
+...
+  // comparisons
+  template<class Y> bool operator<(weak_ptr<Y> const&) const = delete;
+  template<class Y> bool operator<=(weak_ptr<Y> const&) const = delete;
+  template<class Y> bool operator>(weak_ptr<Y> const&) const = delete;
+  template<class Y> bool operator>=(weak_ptr<Y> const&) const = delete;
+};
+...
+
        + + + + + +
        +

        1257. Header <ios> still contains a concept_map

        +

        Section: 27.5 [iostreams.base] Status: New + Submitter: Beman Dawes Opened: 2009-11-04 Last modified: 2009-11-04

        +

        View all other issues in [iostreams.base].

        +

        View all issues with New status.

        +

        Discussion:

        +

        +The current WP still contains a concept_map. +

        + + +

        Proposed resolution:

        +

        +Change Iostreams base classes 27.5 [iostreams.base], Header <ios> synopsis, +as indicated: +

        + +
        concept_map ErrorCodeEnum<io_errc> { };
+template <> struct is_error_code_enum<io_errc> : true_type { }
+error_code make_error_code(io_errc e);
+error_condition make_error_condition(io_errc e);
+const error_category& iostream_category();
+
        + + + + + + +
        +

        1258. std::function Effects clause impossible to satisfy

        +

        Section: 20.7.15.2.2 [func.wrap.func.mod] Status: New + Submitter: Daniel Krügler Opened: 2009-11-05 Last modified: 2009-11-05

        +

        View all issues with New status.

        +

        Discussion:

        +

        +As of 20.7.15.2.2 [func.wrap.func.mod]/2+ we have the following +prototype description: +

        + +
        template<class F, Allocator Alloc>
+  requires Callable<F, ArgTypes...>
+    && Convertible<Callable<F, ArgTypes...>::result_type, R>
+  void assign(F, const Alloc&);
+
        +
        +Effects: function(f, a).swap(*this) +
        +
        + +

        +Two things: First the concept debris needs to be removed, second and +much more importantly, the effects clause is now impossible to satisfy, +because there is no constructor that would match the parameter sequence +(FunctionObject, Allocator) [plus the fact that no +f and no a is part of the signature]. The most +probable candidate is +

        + +
        template<class F, class A> function(allocator_arg_t, const A&, F);
+
        + +

        +and the effects clause needs to be adapted to use this signature. +

        + + +

        Proposed resolution:

        +

        +Change in 20.7.15.2.2 [func.wrap.func.mod] the complete prototype description as +indicated +

        +

        [ +Question to +the editor: Shouldn't there a paragraph number in front of the Effects clause? +]

        + + +
        template<class F, Allocator Alloc>
+  requires Callable<F, ArgTypes...>
+    && Convertible<Callable<F, ArgTypes...>::result_type, R>
+  void assign(F, const Alloc&);
+template<class F, class A> void assign(F f, const A& a);
+
        +
        +3 Effects: function(f, aallocator_arg, a, +f).swap(*this) +
        +
        + + + + + +
        +

        1259. Should initializer-list constructors move elements?

        +

        Section: 23.2.3 [sequence.reqmts] Status: New + Submitter: Sean Hunt Opened: 2009-11-05 Last modified: 2009-11-06

        +

        View other active issues in [sequence.reqmts].

        +

        View all other issues in [sequence.reqmts].

        +

        View all issues with New status.

        +

        Discussion:

        +

        +According to 23.2.3 [sequence.reqmts], X(il) is +equivalent to X(il.begin(), il.end()). Should it instead be +equivalent to X(move_iterator(il.begin()), +move_iterator(il.end())) so that needless copies are not made? This +doesn't seem ideal either - it may make more sense to provide two +overloads for the constructor, one for move and one for copy. +

        + + +

        Proposed resolution:

        +

        +

        + + + + + +
        +

        1260. is_constructible<int*,void*> reports true

        +

        Section: 20.6.4.3 [meta.unary.prop] Status: New + Submitter: Peter Dimov Opened: 2009-11-07 Last modified: 2009-11-08

        +

        View other active issues in [meta.unary.prop].

        +

        View all other issues in [meta.unary.prop].

        +

        View all issues with New status.

        +

        Discussion:

        +

        +The specification of is_constructible<T,Args...> in +N3000 +uses +

        + +
        static_cast<T>(create<Args>()...)
+
        + +

        +for the one-argument case, but static_cast also permits +unwanted conversions such as void* to T* and +Base* to Derived*. +

        + + +

        Proposed resolution:

        +

        +Change 20.6.4.3 [meta.unary.prop], p6: +

        + +
        +

        +the predicate condition for a template specialization +is_constructible<T, Args> shall be satisfied, if and only +if the following expression CE variable +definition would be well-formed: +

        + +
          +
        • +

          +if sizeof...(Args) == 0 1, the expression: +

          +
          static_cast<T>(create<Args>()...)
+T t;
+
          +
          • +
        • +

          +otherwise the expression: +

          +
          T t(create<Args>()...);
+
          +
          • +
        +
        + + + + + \ No newline at end of file diff --git a/libstdc++-v3/doc/html/ext/lwg-closed.html b/libstdc++-v3/doc/html/ext/lwg-closed.html index ce7faf5fccc..7839575d728 100644 --- a/libstdc++-v3/doc/html/ext/lwg-closed.html +++ b/libstdc++-v3/doc/html/ext/lwg-closed.html @@ -7,6 +7,14 @@ @@ -14,11 +22,11 @@ del {background-color:#FFA0A0} - + - + @@ -29,7 +37,7 @@ del {background-color:#FFA0A0}
        Doc. no.N2942=09-0132N3013=09-0203
        Date:2009-08-022009-11-08
        Project:Howard Hinnant <howard.hinnant@gmail.com>
        -

        C++ Standard Library Closed Issues List (Revision R66)

        +

        C++ Standard Library Closed Issues List (Revision R68)

        Reference ISO/IEC IS 14882:2003(E)

        Also see:

        @@ -51,6 +59,76 @@ del {background-color:#FFA0A0}

        Revision History

        @@ -112,24 +190,24 @@ del {background-color:#FFA0A0}
      5. 1143 issues total, up by 32.
  • Details:
    • @@ -142,7 +220,7 @@ del {background-color:#FFA0A0}
  • 1111 issues total, up by 19.
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    • @@ -159,9 +237,9 @@ del {background-color:#FFA0A0}
  • Details:
    • @@ -192,7 +270,7 @@ del {background-color:#FFA0A0}
  • 982 issues total, up by 44.
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    • @@ -205,7 +283,7 @@ del {background-color:#FFA0A0}
  • 938 issues total, up by 20.
  • Details:
    • @@ -219,28 +297,28 @@ del {background-color:#FFA0A0}
  • Details:
    • @@ -254,7 +332,7 @@ del {background-color:#FFA0A0}
  • 878 issues total, up by 9.
  • Details:
    • @@ -285,21 +363,21 @@ del {background-color:#FFA0A0}
  • Details:
  • Details:
    • @@ -331,7 +409,7 @@ del {background-color:#FFA0A0}
  • Details:
  • Details:
    • Added the following New issues: 755, 756, 757, 758, 759, 760, 761, 762, 763, 764.
      • -
    • Changed the following issues from NAD to Open: 463.
      • +
    • Changed the following issues from NAD to Open: 463.
    • Changed the following issues from Pending WP to WP: 607, 608, 654, 655, 677, 682.
    • @@ -402,7 +480,7 @@ del {background-color:#FFA0A0}
  • Changed the following issues from NAD Future to Dup: 77, 350.
  • Changed the following issues from New to NAD: 639, 657, 663.
  • Changed the following issues from Open to NAD: 548.
    • -
  • Changed the following issues from New to Open: 546, 550, 564, 565, 573, 585, 588, 627, 629, 630, 632, 635, 653, 659, 667, 668, 669, 670, 671, 673, 686, 704, 707, 708.
    • +
  • Changed the following issues from New to Open: 546, 550, 564, 565, 573, 585, 588, 627, 629, 630, 632, 635, 653, 659, 667, 668, 669, 670, 671, 673, 686, 704, 707, 708.
  • Changed the following issues from New to Pending NAD Editorial: 393, 592.
  • Changed the following issues from New to Pending WP: 607, 608, 654, 655, 677, 682.
  • Changed the following issues from New to Ready: 561, 562, 563, 567, 581, 595, 620, 621, 622, 623, 624, 661, 664, 665, 666, 674, 675, 676, 679, 687, 688, 689, 693, 694, 695, 700, 703, 705, 706.
    • @@ -423,7 +501,7 @@ del {background-color:#FFA0A0}
  • 723 issues total, up by 15.
  • Details:
    • @@ -463,7 +541,7 @@ del {background-color:#FFA0A0}
  • 696 issues total, up by 20.
  • Details:
  • Details:
  • Details:
    • @@ -525,7 +603,7 @@ del {background-color:#FFA0A0}
  • 619 issues total, up by 10.
  • Details:
    • @@ -557,7 +635,7 @@ del {background-color:#FFA0A0}
  • 592 issues total, up by 5.
  • Details:
    • @@ -570,7 +648,7 @@ del {background-color:#FFA0A0}
  • 587 issues total, up by 13.
  • Details:
    • @@ -587,7 +665,7 @@ del {background-color:#FFA0A0}
  • Details:
  • Details:
    • @@ -618,7 +696,7 @@ del {background-color:#FFA0A0}
  • 535 issues total.
  • Details:
    • @@ -627,7 +705,7 @@ del {background-color:#FFA0A0} Added new issues 526-528. Moved issues 280, 461, 464, 465, 467, 468, 474, 496 from Ready to WP as per the vote from Mont Tremblant. Moved issues 247, 294, 342, 362, 369, 371, 376, 384, 475, 478, 495, 497 from Review to Ready. -Moved issues 498, 504, 506, 509, 510, 511, 512, 513, 514 from New to Open. +Moved issues 498, 504, 506, 509, 510, 511, 512, 513, 514 from New to Open. Moved issues 505, 507, 508, 519 from New to Ready. Moved issue 500 from New to NAD. Moved issue 518 from New to Review. @@ -639,7 +717,7 @@ Added new issues 498-503. +Added new issues 498-503.
  • R36: 2005-04 post-Lillehammer mailing. All issues in "ready" status except @@ -663,7 +741,7 @@ new issues 463-478. +new issues 463-478.
  • R30: Post-Sydney mailing: reflects decisions made at the Sydney meeting. @@ -678,7 +756,7 @@ Post-Kona mailing: reflects decisions made at the Kona meeting. Added new issues 432-440.
  • R27: -Pre-Kona mailing. Added new issues 404-431. +Pre-Kona mailing. Added new issues 404-431.
  • R26: Post-Oxford mailing: reflects decisions made at the Oxford meeting. @@ -862,7 +940,7 @@ format, 2. Auto_ptr conversions effects incorrect -

    Section: D.9.1.3 [auto.ptr.conv] Status: NAD +

    Section: D.10.1.3 [auto.ptr.conv] Status: NAD Submitter: Nathan Myers Opened: 1997-12-04 Last modified: 2006-12-29

    View all issues with NAD status.

    Discussion:

    @@ -962,9 +1040,8 @@ intended here.

    12. Way objects hold allocators unclear

    -

    Section: X [allocator.requirements] Status: NAD +

    Section: 20.2.2 [allocator.requirements] Status: NAD Submitter: Angelika Langer Opened: 1998-02-23 Last modified: 2006-12-30

    -

    View other active issues in [allocator.requirements].

    View all other issues in [allocator.requirements].

    View all issues with NAD status.

    Discussion:

    @@ -1065,7 +1142,7 @@ this is the intent of the LWG.

    65. Underspecification of strstreambuf::seekoff

    -

    Section: D.7.1.3 [depr.strstreambuf.virtuals] Status: NAD +

    Section: D.8.1.3 [depr.strstreambuf.virtuals] Status: NAD Submitter: Matt Austern Opened: 1998-08-18 Last modified: 2006-12-27

    View all other issues in [depr.strstreambuf.virtuals].

    View all issues with NAD status.

    @@ -1238,6 +1315,7 @@ otherwise possible.

    82. Missing constant for set elements

    Section: 23.2.4 [associative.reqmts] Status: NAD Submitter: Nico Josuttis Opened: 1998-09-29 Last modified: 2007-01-15

    +

    View other active issues in [associative.reqmts].

    View all other issues in [associative.reqmts].

    View all issues with NAD status.

    Discussion:

    @@ -1468,7 +1546,7 @@ may be provided by a non-Standard implementation class:

    Proposed resolution:

    -

    Add a new subclause [presumably 17.4.4.9] following 17.6.4.10 [res.on.exception.handling]:

    +

    Add a new subclause [presumably 17.4.4.9] following 17.6.4.11 [res.on.exception.handling]:

    17.4.4.9 Template Parameters

    A specialization of a @@ -1549,6 +1627,196 @@ illegal.  See 17.6.4.5 [member.functions] paragraph 2.

    +
    +

    96. Vector<bool> is not a container

    +

    Section: 23.3.6 [vector] Status: NAD + Submitter: AFNOR Opened: 1998-10-07 Last modified: 2009-10-26

    +

    View all other issues in [vector].

    +

    View all issues with NAD status.

    +

    Discussion:

    +

    vector<bool> is not a container as its reference and +pointer types are not references and pointers.

    + +

    Also it forces everyone to have a space optimization instead of a +speed one.

    + +

    See also: 99-0008 == N1185 Vector<bool> is +Nonconforming, Forces Optimization Choice.

    + +

    [In Santa Cruz the LWG felt that this was Not A Defect.]

    + + +

    [In Dublin many present felt that failure to meet Container +requirements was a defect. There was disagreement as to whether +or not the optimization requirements constituted a defect.]

    + + +

    [The LWG looked at the following resolutions in some detail: +
    +     * Not A Defect.
    +     * Add a note explaining that vector<bool> does not meet +Container requirements.
    +     * Remove vector<bool>.
    +     * Add a new category of container requirements which +vector<bool> would meet.
    +     * Rename vector<bool>.
    +
    +No alternative had strong, wide-spread, support and every alternative +had at least one "over my dead body" response.
    +
    +There was also mention of a transition scheme something like (1) add +vector_bool and deprecate vector<bool> in the next standard. (2) +Remove vector<bool> in the following standard.]

    + + +

    [Modifying container requirements to permit returning proxies +(thus allowing container requirements conforming vector<bool>) +was also discussed.]

    + + +

    [It was also noted that there is a partial but ugly workaround in +that vector<bool> may be further specialized with a customer +allocator.]

    + + +

    [Kona: Herb Sutter presented his paper J16/99-0035==WG21/N1211, +vector<bool>: More Problems, Better Solutions. Much discussion +of a two step approach: a) deprecate, b) provide replacement under a +new name. LWG straw vote on that: 1-favor, 11-could live with, 2-over +my dead body. This resolution was mentioned in the LWG report to the +full committee, where several additional committee members indicated +over-my-dead-body positions.]

    + + +

    Discussed at Lillehammer. General agreement that we should + deprecate vector<bool> and introduce this functionality under + a different name, e.g. bit_vector. This might make it possible to + remove the vector<bool> specialization in the standard that comes + after C++0x. There was also a suggestion that + in C++0x we could additional say that it's implementation defined + whether vector<bool> refers to the specialization or to the + primary template, but there wasn't general agreement that this was a + good idea.

    + +

    We need a paper for the new bit_vector class.

    + +

    [ +Batavia: +]

    + +
    +The LWG feels we need something closer to SGI's bitvector to ease migration +from vector<bool>. Although some of the funcitonality from +N2050 +could well be used in such a template. The concern is easing the API migration for those +users who want to continue using a bit-packed container. Alan and Beman to work. +
    + +

    [ +Post Summit Alisdair adds: +]

    + + +
    +

    +vector<bool> is now a conforming container under the revised terms of C++0x, +which supports containers of proxies. +

    +

    +Recommend NAD. +

    +

    +Two issues remain: +

    +

    +i/ premature optimization in the specification. +There is still some sentiment that deprecation is the correct way to go, +although it is still not clear what it would mean to deprecate a single +specialization of a template. +

    +

    +Recommend: Create a new issue for the discussion, leave as Open. +

    +

    +ii/ Request for a new bitvector class to guarantee the optimization, perhaps +with a better tuned interface. +

    +

    +This is a clear extension request that may be handled via a future TR. +

    +
    + +

    [ +Batavia (2009-05): +]

    + +
    +We note that most of this issue has become moot over time, +and agree with Alisdair's recommendations. +Move to NAD Future for reconsideration of part (ii). +
    + +

    [ +2009-07-29 Alisdair reopens: +]

    + + +
    +

    +This infamous issue was closed as NAD Future when concepts introduced +support for proxy iterators, so the only remaining requirement was to +provide a better type to support bitsets of dynamic length. I fear we +must re-open this issue until the post-concept form of iterators is +available, and hopefully will support the necessary proxy functionality +to allow us to close this issue as NAD. +

    + +

    +I recommend we spawn a separate issue (1184) requesting a dynamic length bitset +and pre-emptively file it as NAD Future. It is difficult to resolve #96 +when it effectively contains two separate sub-issues. +

    +
    + +

    [ +2009-10 Santa Cruz: +]

    + + +
    +Mark as NAD, and give rationale. +
    + + + +

    Proposed resolution:

    +

    +We now have: +N2050 +and +N2160. +

    + + + +

    Rationale:

    +

    +We want to support proxy iterators but that is going to be separate +work. Don't want to see this issue come back in these kinds of terms. +We're interested in a separate container, and proxy iterators, but both +of those are separate issues. +

    +

    +We've looked at a lot of ways to fix this that would be close to this, +but those things would break existing code. Attempts to fix this +directly have not been tractable, and removing it has not been +tractable. Therefore we are closing. +

    + + + + +

    97. Insert inconsistent definition

    Section: 23 [containers] Status: NAD @@ -1572,7 +1840,7 @@ the design, for better or for worse.

    99. Reverse_iterator comparisons completely wrong

    -

    Section: 24.5.1.2.13 [reverse.iter.op==] Status: NAD +

    Section: 24.5.1.3.13 [reverse.iter.op==] Status: NAD Submitter: AFNOR Opened: 1998-10-07 Last modified: 2006-12-27

    View all issues with NAD status.

    Discussion:

    @@ -1594,9 +1862,8 @@ exactly what the Standard says.

    100. Insert iterators/ostream_iterators overconstrained

    -

    Section: 24.7 [insert.iterators], 24.6.4 [ostreambuf.iterator] Status: NAD +

    Section: 24.5.2 [insert.iterators], 24.6.4 [ostreambuf.iterator] Status: NAD Submitter: AFNOR Opened: 1998-10-07 Last modified: 2006-12-27

    -

    View other active issues in [insert.iterators].

    View all other issues in [insert.iterators].

    View all issues with NAD status.

    Discussion:

    @@ -1619,7 +1886,6 @@ incorrect code to work, rather than the other way around.

    101. No way to free storage for vector and deque

    Section: 23.3.6 [vector], 23.3.1 [array] Status: NAD Submitter: AFNOR Opened: 1998-10-07 Last modified: 2007-02-19

    -

    View other active issues in [vector].

    View all other issues in [vector].

    View all issues with NAD status.

    Discussion:

    @@ -1646,6 +1912,7 @@ expressed in a single line of code (where v is

    102. Bug in insert range in associative containers

    Section: 23.2.4 [associative.reqmts] Status: Dup Submitter: AFNOR Opened: 1998-10-07 Last modified: 2006-12-30

    +

    View other active issues in [associative.reqmts].

    View all other issues in [associative.reqmts].

    View all issues with Dup status.

    Duplicate of: 264

    @@ -1783,7 +2050,7 @@ Post Summit Daniel adds: Recommend NAD. The proposed wording would violate the axioms of concept requirement EqualityComparable axioms as part of concept InputIterator and more specifically it would violate the explicit wording of -24.2.2 [input.iterators]/7: +24.2.1 [input.iterators]/7:

    @@ -1875,7 +2142,7 @@ desired functionality.

    116. bitset cannot be constructed with a const char*

    -

    Section: 20.3.6 [template.bitset] Status: Dup +

    Section: 20.3.7 [template.bitset] Status: Dup Submitter: Judy Ward Opened: 1998-11-06 Last modified: 2008-03-14

    View other active issues in [template.bitset].

    View all other issues in [template.bitset].

    @@ -1921,13 +2188,13 @@ longer work.

    Proposed resolution:

    -

    Add to 20.3.6 [template.bitset] a bitset constructor declaration

    +

    Add to 20.3.7 [template.bitset] a bitset constructor declaration

    explicit bitset(const char*);
    -

    and in Section 20.3.6.1 [bitset.cons] add:

    +

    and in Section 20.3.7.1 [bitset.cons] add:

    explicit bitset(const char* str);
    @@ -2060,6 +2327,7 @@ retained for future reference.

    131. list::splice throws nothing

    Section: 23.3.4.4 [list.ops] Status: NAD Submitter: Howard Hinnant Opened: 1999-03-06 Last modified: 2007-02-19

    +

    View other active issues in [list.ops].

    View all other issues in [list.ops].

    View all issues with NAD status.

    Discussion:

    @@ -2207,7 +2475,7 @@ reconsider for the next standard.

    143. C .h header wording unclear

    -

    Section: D.5 [depr.c.headers] Status: NAD +

    Section: D.6 [depr.c.headers] Status: NAD Submitter: Christophe de Dinechin Opened: 1999-05-04 Last modified: 2006-12-27

    View all issues with NAD status.

    Discussion:

    @@ -2293,7 +2561,7 @@ int main() {

    Proposed resolution:

    -

    Replace D.5 [depr.c.headers] paragraph 2 with:

    +

    Replace D.6 [depr.c.headers] paragraph 2 with:

    @@ -2555,6 +2823,7 @@ ios_base::init to basic_ios::init().)

    188. valarray helpers missing augmented assignment operators

    Section: 26.6.2.6 [valarray.cassign] Status: NAD Submitter: Gabriel Dos Reis Opened: 1999-08-15 Last modified: 2008-03-11

    +

    View all other issues in [valarray.cassign].

    View all issues with NAD status.

    Discussion:

    26.5.2.6 defines augmented assignment operators @@ -2590,7 +2859,7 @@ operators.

    190. min() and max() functions should be std::binary_functions

    -

    Section: 25.5.7 [alg.min.max] Status: NAD +

    Section: 25.4.7 [alg.min.max] Status: NAD Submitter: Mark Rintoul Opened: 1999-08-26 Last modified: 2009-07-14

    View all other issues in [alg.min.max].

    View all issues with NAD status.

    @@ -2634,7 +2903,7 @@ function objects.

    191. Unclear complexity for algorithms such as binary search

    -

    Section: 25.5.3 [alg.binary.search] Status: NAD +

    Section: 25.4.3 [alg.binary.search] Status: NAD Submitter: Nico Josuttis Opened: 1999-10-10 Last modified: 2006-12-27

    View all other issues in [alg.binary.search].

    View all issues with NAD status.

    @@ -2665,6 +2934,7 @@ iterators.

    192. a.insert(p,t) is inefficient and overconstrained

    Section: 23.2.4 [associative.reqmts] Status: NAD Submitter: Ed Brey Opened: 1999-06-06 Last modified: 2006-12-30

    +

    View other active issues in [associative.reqmts].

    View all other issues in [associative.reqmts].

    View all issues with NAD status.

    Duplicate of: 233

    @@ -2833,9 +3103,8 @@ class rdbuf() always returns the original streambuf, whereas the base

    197. max_size() underspecified

    -

    Section: X [allocator.requirements], 23.2 [container.requirements] Status: NAD +

    Section: 20.2.2 [allocator.requirements], 23.2 [container.requirements] Status: NAD Submitter: Andy Sawyer Opened: 1999-10-21 Last modified: 2006-12-30

    -

    View other active issues in [allocator.requirements].

    View all other issues in [allocator.requirements].

    View all issues with NAD status.

    Discussion:

    @@ -2949,7 +3218,7 @@ and is not a defect.

    204. distance(first, last) when "last" is before "first"

    -

    Section: 24.4 [iterator.operations] Status: NAD +

    Section: 24.4.4 [iterator.operations] Status: NAD Submitter: Rintala Matti Opened: 2000-01-28 Last modified: 2008-09-30

    View other active issues in [iterator.operations].

    View all other issues in [iterator.operations].

    @@ -2985,7 +3254,7 @@ category?

    Rationale:

    -

    "Reachable" is defined in the standard in 24.2 [iterator.concepts] paragraph 6. +

    "Reachable" is defined in the standard in X [iterator.concepts] paragraph 6. The definition is only in terms of operator++(). The LWG sees no defect in the standard.

    @@ -3097,6 +3366,7 @@ or write floating point expressions as arguments.

    215. Can a map's key_type be const?

    Section: 23.2.4 [associative.reqmts] Status: NAD Submitter: Judy Ward Opened: 2000-02-29 Last modified: 2006-12-27

    +

    View other active issues in [associative.reqmts].

    View all other issues in [associative.reqmts].

    View all issues with NAD status.

    Discussion:

    @@ -3178,7 +3448,7 @@ occurs additional places in the section, all requiring fixes.]

    218. Algorithms do not use binary predicate objects for default comparisons

    -

    Section: 25.5 [alg.sorting] Status: NAD +

    Section: 25.4 [alg.sorting] Status: NAD Submitter: Pablo Halpern Opened: 2000-03-06 Last modified: 2006-12-27

    View all other issues in [alg.sorting].

    View all issues with NAD status.

    @@ -3214,7 +3484,7 @@ operator<.

    219. find algorithm missing version that takes a binary predicate argument

    -

    Section: 25.3.5 [alg.find] Status: NAD +

    Section: 25.2.5 [alg.find] Status: NAD Submitter: Pablo Halpern Opened: 2000-03-06 Last modified: 2009-07-14

    View all other issues in [alg.find].

    View all issues with NAD status.

    @@ -3254,7 +3524,7 @@ Moved to NAD.

    Proposed resolution:

    -

    In section 25.3.5 [alg.find], add a second prototype for find +

    In section 25.2.5 [alg.find], add a second prototype for find (between the existing prototype and the prototype for find_if), as follows:

        template<class InputIterator, class T, class BinaryPredicate>
@@ -3319,7 +3589,7 @@ ie. the do_is() method as described in 22.4.1.1.2 [locale.ctype.virtual
 
 
    
 
    244. Must find's third argument be CopyConstructible?
    
-
    Section: 25.3.5 [alg.find] Status: NAD
+
    Section: 25.2.5 [alg.find] Status: NAD
  Submitter: Andrew Koenig Opened: 2000-05-02  Last modified: 2006-12-27
    
 
    View all other issues in [alg.find].
    
 
    View all issues with NAD status.
    
@@ -3362,7 +3632,6 @@ might reasonably pass an argument that is not Copy Constructible.
    
 
    245. Which operations on istream_iterator trigger input operations?
    
 
    Section: 24.6.1 [istream.iterator] Status: NAD
  Submitter: Andrew Koenig Opened: 2000-05-02  Last modified: 2006-12-27
    
-
    View other active issues in [istream.iterator].
    
 
    View all other issues in [istream.iterator].
    
 
    View all issues with NAD status.
    
 
    Discussion:
    
@@ -3396,6 +3665,7 @@ how many times find may invoke operator++.
    
 
    246. a.insert(p,t) is incorrectly specified
    
 
    Section: 23.2.4 [associative.reqmts] Status: Dup
  Submitter: Mark Rodgers Opened: 2000-05-19  Last modified: 2007-01-15
    
+
    View other active issues in [associative.reqmts].
    
 
    View all other issues in [associative.reqmts].
    
 
    View all issues with Dup status.
    
 
    Duplicate of: 233
    
@@ -3482,7 +3752,7 @@ Change the words "right after" to "immediately before".
    
 
 
    
 
    249. Return Type of auto_ptr::operator=
    
-
    Section: D.9.1 [auto.ptr] Status: NAD
+
    Section: D.10.1 [auto.ptr] Status: NAD
  Submitter: Joseph Gottman Opened: 2000-06-30  Last modified: 2006-12-29
    
 
    View all other issues in [auto.ptr].
    
 
    View all issues with NAD status.
    
@@ -3629,7 +3899,7 @@ signature.
    
 
 
    
 
    257. STL functional object and iterator inheritance.
    
-
    Section: 20.7.3 [base], D.10.2 [iterator.basic] Status: NAD
+
    Section: 20.7.3 [base], 24.4.2 [iterator.basic] Status: NAD
  Submitter: Robert Dick  Opened: 2000-08-17  Last modified: 2006-12-29
    
 
    View all other issues in [base].
    
 
    View all issues with NAD status.
    
@@ -3713,7 +3983,7 @@ want to pass temporaries as traits or tag types in generic code.
 
 
    
 
    267. interaction of strstreambuf::overflow() and seekoff()
    
-
    Section: D.7.1.3 [depr.strstreambuf.virtuals] Status: NAD
+
    Section: D.8.1.3 [depr.strstreambuf.virtuals] Status: NAD
  Submitter: Martin Sebor Opened: 2000-10-05  Last modified: 2007-01-15
    
 
    View all other issues in [depr.strstreambuf.virtuals].
    
 
    View all issues with NAD status.
    
@@ -3777,7 +4047,7 @@ behavior of the program is undefined.
 
    Proposed resolution:
    
 
 
-   
    Change the last sentence of D.7.1 [depr.strstreambuf] paragraph 4 from
    
+   
    Change the last sentence of D.8.1 [depr.strstreambuf] paragraph 4 from
    
 
       
    
       Otherwise, seeklow equals gbeg and seekhigh is either pend, if
@@ -3878,9 +4148,8 @@ necessary.
 
 
    
 
    277. Normative encouragement in allocator requirements unclear
    
-
    Section: X [allocator.requirements] Status: NAD
+
    Section: 20.2.2 [allocator.requirements] Status: NAD
  Submitter: Matt Austern Opened: 2000-11-07  Last modified: 2006-12-30
    
-
    View other active issues in [allocator.requirements].
    
 
    View all other issues in [allocator.requirements].
    
 
    View all issues with NAD status.
    
 
    Discussion:
    
@@ -4123,7 +4392,7 @@ never referred to by the C++ standard.
    
 
 
    
 
    290. Requirements to for_each and its function object
    
-
    Section: 25.3.4 [alg.foreach] Status: NAD
+
    Section: 25.2.4 [alg.foreach] Status: NAD
  Submitter: Angelika Langer Opened: 2001-01-03  Last modified: 2009-07-14
    
 
    View all other issues in [alg.foreach].
    
 
    View all issues with NAD status.
    
@@ -4186,7 +4455,7 @@ of the library.
 
 
    
 
    293. Order of execution in transform algorithm
    
-
    Section: 25.4.4 [alg.transform] Status: NAD
+
    Section: 25.3.4 [alg.transform] Status: NAD
  Submitter: Angelika Langer Opened: 2001-01-04  Last modified: 2007-01-15
    
 
    View all other issues in [alg.transform].
    
 
    View all issues with NAD status.
    
@@ -4253,35 +4522,6 @@ wrapping it in an Input Iterator adaptor.
    
 
 
 
-
    
-
    296. Missing descriptions and requirements of pair operators
    
-
    Section: 20.3.3 [pairs] Status: NAD
- Submitter: Martin Sebor Opened: 2001-01-14  Last modified: 2006-12-27
    
-
    View other active issues in [pairs].
    
-
    View all other issues in [pairs].
    
-
    View all issues with NAD status.
    
-
    Discussion:
    
-
    The synopsis of the header <utility> in 20.3 [utility]
-lists the complete set of equality and relational operators for pair
-but the section describing the template and the operators only describes
-operator==() and operator<(), and it fails to mention
-any requirements on the template arguments. The remaining operators are
-not mentioned at all.
-
     
-
-
-
    Rationale:
    
-
    20.3.1 [operators] paragraph 10 already specifies the semantics.
-That paragraph says that, if declarations of operator!=, operator>,
-operator<=, and operator>= appear without definitions, they are
-defined as specified in 20.3.1 [operators].  There should be no user
-confusion, since that paragraph happens to immediately precede the
-specification of pair.
    
-
-
-
-
-
 
    
 
    302. Need error indication from codecvt<>::do_length
    
 
    Section: 22.4.1.5 [locale.codecvt.byname] Status: NAD
@@ -4355,9 +4595,8 @@ external characters, it stops.
    
 
 
    
 
    304. Must *a return an lvalue when a is an input iterator?
    
-
    Section: 24.2 [iterator.concepts] Status: NAD
+
    Section: X [iterator.concepts] Status: NAD
  Submitter: Dave Abrahams Opened: 2001-02-05  Last modified: 2008-09-30
    
-
    View other active issues in [iterator.concepts].
    
 
    View all other issues in [iterator.concepts].
    
 
    View all issues with NAD status.
    
 
    Discussion:
    
@@ -5093,7 +5332,7 @@ Ready state:
 
  • It should apply to both overloads of seekg.
    • 
 
  • tellg has similar issues, except that it should not call clear().
    • 
 
  • The point about clear() seems to apply to seekp().
    • 
-
  • Depending on the outcome of 419
+
  • Depending on the outcome of 419
 if the sentry
 sets failbit when it finds eofbit already set, then
 you can never seek away from the end of stream.
    • 
@@ -5289,7 +5528,7 @@ author.
 
 
 
    
-NAD. Handled by LWG 1178.
+NAD. Handled by LWG 1178.
 
    
 
 
@@ -5438,12 +5677,12 @@ consensus in the LWG for action.
 
 
    
 
    348. Minor issue with std::pair operator<
    
-
    Section: 20.3.3 [pairs] Status: Dup
+
    Section: 20.3.4 [pairs] Status: Dup
  Submitter: Andy Sawyer Opened: 2001-10-23  Last modified: 2008-01-05
    
 
    View other active issues in [pairs].
    
 
    View all other issues in [pairs].
    
 
    View all issues with Dup status.
    
-
    Duplicate of: 532
    
+
    Duplicate of: 532
    
 
    Discussion:
    
 
 
@@ -5454,7 +5693,7 @@ operator< on any pair type which contains a pointer.
 
 
 
    Proposed resolution:
    
-
    In 20.3.3 [pairs] paragraph 6, replace:
    
+
    In 20.3.4 [pairs] paragraph 6, replace:
    
 
        Returns: x.first < y.first || (!(y.first < x.first) && x.second <
         y.second).
 
    
@@ -5487,7 +5726,7 @@ operator< on any pair type which contains a pointer.
 
 
    
 
    350. allocator<>::address
    
-
    Section: 20.8.4.1 [allocator.members], X [allocator.requirements], 17.6.1.1 [contents] Status: Dup
+
    Section: 20.8.8.1 [allocator.members], 20.2.2 [allocator.requirements], 17.6.1.1 [contents] Status: Dup
  Submitter: Nathan Myers Opened: 2001-10-25  Last modified: 2007-10-11
    
 
    View all other issues in [allocator.members].
    
 
    View all issues with Dup status.
    
@@ -5552,7 +5791,7 @@ a.address(s) lines, respectively:
 
 
    Rationale:
    
 
    The LWG believes both examples are ill-formed.  The contained type
-is required to be CopyConstructible (X [utility.arg.requirements]), and that
+is required to be CopyConstructible (20.2.1 [utility.arg.requirements]), and that
 includes the requirement that &t return the usual types and
 values. Since allocators are intended to be used in conjunction with
 containers, and since the CopyConstructible requirements appear to
@@ -5580,7 +5819,7 @@ exhibiting a problem.
    
 
    
 In 20.7 [function.objects] the header <functional> synopsis declares
 the unary_negate and binary_negate function objects as struct.
-However in 20.7.11 [negators] the unary_negate and binary_negate
+However in 20.7.10 [negators] the unary_negate and binary_negate
 function objects are defined as class.  Given the context, they are
 not "basic function objects" like negate, so this is either a typo or
 an editorial oversight.
@@ -5591,7 +5830,7 @@ an editorial oversight.
 
 
 
    Proposed resolution:
    
-
    Change the synopsis to reflect the useage in 20.7.11 [negators]
    
+
    Change the synopsis to reflect the useage in 20.7.10 [negators]
    
 
 
    [Curaçao: Since the language permits "struct", the LWG
 views this as NAD. They suggest, however, that the Project Editor
@@ -5605,7 +5844,7 @@ might wish to make the change as editorial.]
    
 
 
    
 
    353. std::pair missing template assignment
    
-
    Section: 20.3.3 [pairs] Status: NAD Editorial
+
    Section: 20.3.4 [pairs] Status: NAD Editorial
  Submitter: Martin Sebor Opened: 2001-12-02  Last modified: 2008-01-05
    
 
    View other active issues in [pairs].
    
 
    View all other issues in [pairs].
    
@@ -6056,13 +6295,13 @@ those terms, does not appear in the standard.]
    
 
 
    
 
    367. remove_copy/remove_copy_if and Input Iterators
    
-
    Section: 25.4.8 [alg.remove] Status: NAD
+
    Section: 25.3.8 [alg.remove] Status: NAD
  Submitter: Anthony Williams Opened: 2002-05-13  Last modified: 2006-12-27
    
 
    View all other issues in [alg.remove].
    
 
    View all issues with NAD status.
    
 
    Discussion:
    
 
    
-remove_copy and remove_copy_if (25.4.8 [alg.remove]) permit their
+remove_copy and remove_copy_if (25.3.8 [alg.remove]) permit their
 input range to be marked with Input Iterators. However, since two
 operations are required against the elements to copy (comparison and
 assigment), when the input range uses Input Iterators, a temporary
@@ -6079,7 +6318,7 @@ result maintained, so the temporary is not required.
 Add "If InputIterator does not meet the requirements of forward
 iterator, then the value type of InputIterator must be copy
 constructible. Otherwise copy constructible is not required." to
-25.4.8 [alg.remove] paragraph 6.
+25.3.8 [alg.remove] paragraph 6.
 
    
 
 
@@ -6125,13 +6364,13 @@ part of the "Effects" paragraph.
 
 
    
 
    372. Inconsistent description of stdlib exceptions
    
-
    Section: 17.6.4.10 [res.on.exception.handling], 18.7.1 [type.info] Status: NAD
+
    Section: 17.6.4.11 [res.on.exception.handling], 18.7.1 [type.info] Status: NAD
  Submitter: Randy Maddox Opened: 2002-07-22  Last modified: 2006-12-27
    
 
    View all other issues in [res.on.exception.handling].
    
 
    View all issues with NAD status.
    
 
    Discussion:
    
 
-
    Paragraph 3 under clause 17.6.4.10 [res.on.exception.handling], Restrictions on
+
    Paragraph 3 under clause 17.6.4.11 [res.on.exception.handling], Restrictions on
 Exception Handling, states that "Any other functions defined in the
 C++ Standard Library that do not have an exception-specification may
 throw implementation-defined exceptions unless otherwise specified."
@@ -6422,7 +6661,7 @@ NAD without prejudice. Will reopen if proposed resolution is supplied.
 
    
 Many function templates have parameters that are passed by value;
 a typical example is find_if's pred parameter in
-25.3.5 [alg.find].  Are the corresponding template parameters
+25.2.5 [alg.find].  Are the corresponding template parameters
 (Predicate in this case) implicitly required to be
 CopyConstructible, or does that need to be spelled out explicitly?
 
    
@@ -6564,7 +6803,7 @@ provide their own comparison function object.
    
 
 
    
 
    390. CopyConstructible requirements too strict
    
-
    Section: X [utility.arg.requirements] Status: NAD Editorial
+
    Section: 20.2.1 [utility.arg.requirements] Status: NAD Editorial
  Submitter: Doug Gregor Opened: 2002-10-24  Last modified: 2008-03-14
    
 
    View other active issues in [utility.arg.requirements].
    
 
    View all other issues in [utility.arg.requirements].
    
@@ -6632,14 +6871,14 @@ that &t and &u return the address of t and u, respectively.
 
 
    
 
    392. 'equivalence' for input iterators
    
-
    Section: 24.2.2 [input.iterators] Status: NAD
+
    Section: 24.2.1 [input.iterators] Status: NAD
  Submitter: Corwin Joy Opened: 2002-12-11  Last modified: 2006-12-27
    
 
    View all other issues in [input.iterators].
    
 
    View all issues with NAD status.
    
 
    Discussion:
    
 
 
    
-In section 24.2.2 [input.iterators] table 72 -
+In section 24.2.1 [input.iterators] table 72 -
 'Input Iterator Requirements' we have as a postcondition of *a:
 "If a==b and (a, b) is in the domain of == then *a is equivalent to *b".
 
    
@@ -7419,12 +7658,12 @@ is not so clear (see list 3).
 List 1 -- Examples of (presumably) normative Notes:
 
    
 
-20.8.4.1 [allocator.members], p3,
    
-20.8.4.1 [allocator.members], p10,
    
+20.8.8.1 [allocator.members], p3,
    
+20.8.8.1 [allocator.members], p10,
    
 21.4.2 [string.cons], p11,
    
 22.3.1.2 [locale.cons], p11,
    
 23.3.2.3 [deque.modifiers], p2,
    
-25.5.7 [alg.min.max], p3,
    
+25.4.7 [alg.min.max], p3,
    
 26.4.6 [complex.ops], p15,
    
 27.6.2.4.3 [streambuf.virt.get], p7.
    
 
    
@@ -7435,7 +7674,7 @@ List 2 -- Examples of (presumably) informative Notes:
 18.6.1.3 [new.delete.placement], p3,
    
 21.4.6.6 [string::replace], p14,
    
 22.4.1.4.2 [locale.codecvt.virtuals], p3,
    
-25.3.4 [alg.foreach], p4,
    
+25.2.4 [alg.foreach], p4,
    
 26.4.5 [complex.member.ops], p1,
    
 27.5.2.5 [ios.base.storage], p6.
    
 
    
@@ -7548,6 +7787,115 @@ to
 
 
 
+
    
+
    431. Swapping containers with unequal allocators
    
+
    Section: 20.2.2 [allocator.requirements], 25 [algorithms] Status: NAD Editorial
+ Submitter: Matt Austern Opened: 2003-09-20  Last modified: 2009-10-26
    
+
    View all other issues in [allocator.requirements].
    
+
    View all issues with NAD Editorial status.
    
+
    Discussion:
    
+
    Clause 20.2.2 [allocator.requirements] paragraph 4 says that implementations
+  are permitted to supply containers that are unable to cope with
+  allocator instances and that container implementations may assume
+  that all instances of an allocator type compare equal.  We gave
+  implementers this latitude as a temporary hack, and eventually we
+  want to get rid of it.  What happens when we're dealing with
+  allocators that don't compare equal?
+
    
+
+
    In particular: suppose that v1 and v2 are both
+  objects of type vector<int, my_alloc> and that
+  v1.get_allocator() != v2.get_allocator().  What happens if
+  we write v1.swap(v2)?  Informally, three possibilities:
    
+
+
    1. This operation is illegal.  Perhaps we could say that an
+  implementation is required to check and to throw an exception, or
+  perhaps we could say it's undefined behavior.
    
+
    2. The operation performs a slow swap (i.e. using three
+  invocations of operator=, leaving each allocator with its
+  original container.  This would be an O(N) operation.
    
+
    3. The operation swaps both the vectors' contents and their
+  allocators.  This would be an O(1) operation. That is:
    
+  
    
+  
        my_alloc a1(...);
+    my_alloc a2(...);
+    assert(a1 != a2);
+
+    vector<int, my_alloc> v1(a1);
+    vector<int, my_alloc> v2(a2);
+    assert(a1 == v1.get_allocator());
+    assert(a2 == v2.get_allocator());
+
+    v1.swap(v2);
+    assert(a1 == v2.get_allocator());
+    assert(a2 == v1.get_allocator());
+  
    
+  
    
+
+
    [Kona: This is part of a general problem.  We need a paper
+  saying how to deal with unequal allocators in general.]
    
+
+
+
    [pre-Sydney: Howard argues for option 3 in
+N1599.
+]
    
+
+
+
    [
+2007-01-12, Howard:  This issue will now tend to come up more often with move constructors
+and move assignment operators.  For containers, these members transfer resources (i.e.
+the allocated memory) just like swap.
+]
    
+
+
+
    [
+Batavia:  There is agreement to overload the container swap on the allocator's Swappable
+requirement using concepts.  If the allocator supports Swappable, then container's swap will
+swap allocators, else it will perform a "slow swap" using copy construction and copy assignment.
+]
    
+
+
+
    [
+2009-04-28 Pablo adds:
+]
    
+
+
    
+Fixed in
+N2525.
+I argued for marking this Tentatively-Ready right after Bellevue,
+but there was a concern that
+N2525
+would break in the presence of the RVO. (That breakage had nothing to do with
+swap, but never-the-less). I addressed that breakage in in
+N2840
+(Summit) by means of a non-normative reference:
+
+
    
+[Note: in situations where the copy constructor for a container is elided,
+this function is not called. The behavior in these cases is as if
+select_on_container_copy_construction returned x — end note]
+
    
+
+
    
+
+
    [
+2009-10 Santa Cruz:
+]
    
+
+
+
    
+NAD Editorial.  Addressed by
+N2982.
+
    
+
+
+
+
    Proposed resolution:
    
+
+
+
+
+
 
    
 
    433. Contradiction in specification of unexpected()
    
 
    Section: 18.8.2.4 [unexpected] Status: NAD
@@ -7800,6 +8148,7 @@ table, in this regard.
 
    451. Associative erase should return an iterator
    
 
    Section: 23.2.4 [associative.reqmts], 23.4 [associative] Status: Dup
  Submitter: Bill Plauger Opened: 2004-01-30  Last modified: 2009-05-01
    
+
    View other active issues in [associative.reqmts].
    
 
    View all other issues in [associative.reqmts].
    
 
    View all issues with Dup status.
    
 
    Duplicate of: 130
    
@@ -8065,6 +8414,104 @@ NAD.
 
 
 
+
    
+
    458. 24.1.5 contains unintended limitation for operator-
    
+
    Section: 24.2.5 [random.access.iterators] Status: NAD
+ Submitter: Daniel Frey Opened: 2004-02-27  Last modified: 2009-10-26
    
+
    View all other issues in [random.access.iterators].
    
+
    View all issues with NAD status.
    
+
    Discussion:
    
+
    
+In 24.1.5 [lib.random.access.iterators], table 76 the operational
+semantics for the expression "r -= n" are defined as "return r += -n".
+This means, that the expression -n must be valid, which is not the case
+for unsigned types.
+
    
+
+
    [
+Sydney: Possibly not a real problem, since difference type is required
+to be a signed integer type. However, the wording in the standard may
+be less clear than we would like.
+]
    
+
+
+
    [
+Post Summit Alisdair adds:
+]
    
+
+
+
    
+
    
+This issue refers to a requirements table we have removed.
+
    
+
    
+The issue might now relate to 24.2.5 [random.access.iterators] p5.
+However, the rationale in the issue already recognises that the
+difference_type must be signed, so this really looks NAD.
+
    
+
    
+
+
    [
+Batavia (2009-05):
+]
    
+
+
    
+
    
+We agree with Alisdair's observations.
+
    
+
    
+Move to NAD.
+
    
+
    
+
+
    [
+2009-07 Frankfurt:
+]
    
+
+
+
    
+
    
+Need to look at again without concepts.
+
    
+
    
+There was a question about this phrase in the discussion: "the
+expression -n must be valid, which is not the case for unsigned types."
+If n is an object ofthe iterator difference_type (eg ptrdiff_t), then it
+is never unsigned.
+
    
+
    
+
+
    [
+2009-10 Santa Cruz:
+]
    
+
+
+
    
+The group reviewed the wording in the draft and agreed that n is of
+difference type, the difference type is signed, and the current wording
+is correct.  Moved to NAD.
+
    
+
+
+
+
    Proposed resolution:
    
+
    
+To remove this limitation, I suggest to change the
+operational semantics for this column to:
+
    
+
        { Distance m = n;
+      if (m >= 0)
+        while (m--) --r;
+      else
+        while (m++) ++r;
+      return r; }
+
    
+
+
+
+
+
+
 
    
 
    459. Requirement for widening in stage 2 is overspecification
    
 
    Section: 22.4.2.1.2 [facet.num.get.virtuals] Status: NAD
@@ -8321,6 +8768,458 @@ Bill agrees issue is no longer serious, and accepts NAD.
 
 
 
+
    
+
    463. auto_ptr usability issues
    
+
    Section: D.10.1 [auto.ptr] Status: NAD
+ Submitter: Rani Sharoni Opened: 2003-12-07  Last modified: 2009-10-26
    
+
    View all other issues in [auto.ptr].
    
+
    View all issues with NAD status.
    
+
    Discussion:
    
+
+
    
+TC1 CWG DR #84 effectively made the template<class Y> operator auto_ptr<Y>()
+member of auto_ptr (20.4.5.3/4) obsolete.
+
    
+
+
    
+The sole purpose of this obsolete conversion member is to enable copy
+initialization base from r-value derived (or any convertible types like
+cv-types) case:
+
    
+
    #include <memory>
+using std::auto_ptr;
+
+struct B {};
+struct D : B {};
+
+auto_ptr<D> source();
+int sink(auto_ptr<B>);
+int x1 = sink( source() ); // #1 EDG - no suitable copy constructor
+
    
+
+
    
+The excellent analysis of conversion operations that was given in the final
+auto_ptr proposal
+(http://anubis.dkuug.dk/jtc1/sc22/wg21/docs/papers/1997/N1128.pdf)
+explicitly specifies this case analysis (case 4). DR #84 makes the analysis
+wrong and actually comes to forbid the loophole that was exploited by the
+auto_ptr designers.
+
    
+
+
    
+I didn't encounter any compliant compiler (e.g. EDG, GCC, BCC and VC) that
+ever allowed this case. This is probably because it requires 3 user defined
+conversions and in fact current compilers conform to DR #84.
+
    
+
+
    
+I was surprised to discover that the obsolete conversion member actually has
+negative impact of the copy initialization base from l-value derived
+case:
    
+
    auto_ptr<D> dp;
+int x2 = sink(dp); // #2 EDG - more than one user-defined conversion applies
+
    
+
+
    
+I'm sure that the original intention was allowing this initialization using
+the template<class Y> auto_ptr(auto_ptr<Y>& a) constructor (20.4.5.1/4) but
+since in this copy initialization it's merely user defined conversion (UDC)
+and the obsolete conversion member is UDC with the same rank (for the early
+overloading stage) there is an ambiguity between them.
+
    
+
+
    
+Removing the obsolete member will have impact on code that explicitly
+invokes it:
+
    
+
    int y = sink(source().operator auto_ptr<B>());
+
    
+
+
    
+IMHO no one ever wrote such awkward code and the reasonable workaround for
+#1 is:
+
    
+
    int y = sink( auto_ptr<B>(source()) );
+
    
+
+
    
+I was even more surprised to find out that after removing the obsolete
+conversion member the initialization was still ill-formed:
+int x3 = sink(dp); // #3 EDG - no suitable copy constructor
+
    
+
+
    
+This copy initialization semantically requires copy constructor which means
+that both template conversion constructor and the auto_ptr_ref conversion
+member (20.4.5.3/3) are required which is what was explicitly forbidden in
+DR #84. This is a bit amusing case in which removing ambiguity results with
+no candidates.
+
    
+
+
    
+I also found exception safety issue with auto_ptr related to auto_ptr_ref:
+
    
+
    int f(auto_ptr<B>, std::string);
+auto_ptr<B> source2();
+
+// string constructor throws while auto_ptr_ref
+// "holds" the pointer
+int x4 = f(source2(), "xyz"); // #4
+
    
+
+
    
+The theoretic execution sequence that will cause a leak:
+
    
+
      
+
    1. call auto_ptr<B>::operator auto_ptr_ref<B>()
      2. 
+
    2. call string::string(char const*) and throw
      3. 
+
    
+
+
    
+According to 20.4.5.3/3 and 20.4.5/2 the auto_ptr_ref conversion member
+returns auto_ptr_ref<Y> that holds *this and this is another defect since
+the type of *this is auto_ptr<X> where X might be different from Y. Several
+library vendors (e.g. SGI) implement auto_ptr_ref<Y> with Y* as member which
+is much more reasonable. Other vendor implemented auto_ptr_ref as
+defectively required and it results with awkward and catastrophic code:
+int oops = sink(auto_ptr<B>(source())); // warning recursive on all control
+paths
+
    
+
+
    
+Dave Abrahams noticed that there is no specification saying that
+auto_ptr_ref copy constructor can't throw.
+
    
+
+
    
+My proposal comes to solve all the above issues and significantly simplify
+auto_ptr implementation. One of the fundamental requirements from auto_ptr
+is that it can be constructed in an intuitive manner (i.e. like ordinary
+pointers) but with strict ownership semantics which yield that source
+auto_ptr in initialization must be non-const. My idea is to add additional
+constructor template with sole propose to generate ill-formed, diagnostic
+required, instance for const auto_ptr arguments during instantiation of
+declaration. This special constructor will not be instantiated for other
+types which is achievable using 14.8.2/2 (SFINAE). Having this constructor
+in hand makes the constructor template<class Y> auto_ptr(auto_ptr<Y> const&)
+legitimate since the actual argument can't be const yet non const r-value
+are acceptable.
+
    
+
+
    
+This implementation technique makes the "private auxiliary class"
+auto_ptr_ref obsolete and I found out that modern C++ compilers (e.g. EDG,
+GCC and VC) consume the new implementation as expected and allow all
+intuitive initialization and assignment cases while rejecting illegal cases
+that involve const auto_ptr arguments.
+
    
+
+
    The proposed auto_ptr interface:
    
+
+
    namespace std {
+    template<class X> class auto_ptr {
+    public:
+        typedef X element_type;
+
+        // 20.4.5.1 construct/copy/destroy:
+        explicit auto_ptr(X* p=0) throw();
+        auto_ptr(auto_ptr&) throw();
+        template<class Y> auto_ptr(auto_ptr<Y> const&) throw();
+        auto_ptr& operator=(auto_ptr&) throw();
+        template<class Y> auto_ptr& operator=(auto_ptr<Y>) throw();
+        ~auto_ptr() throw();
+
+        // 20.4.5.2 members:
+        X& operator*() const throw();
+        X* operator->() const throw();
+        X* get() const throw();
+        X* release() throw();
+        void reset(X* p=0) throw();
+
+    private:
+        template<class U>
+        auto_ptr(U& rhs, typename
+unspecified_error_on_const_auto_ptr<U>::type = 0);
+    };
+}
+
    
+
+
    
+One compliant technique to implement the unspecified_error_on_const_auto_ptr
+helper class is using additional private auto_ptr member class template like
+the following:
+
    
+
    template<typename T> struct unspecified_error_on_const_auto_ptr;
+
+template<typename T>
+struct unspecified_error_on_const_auto_ptr<auto_ptr<T> const>
+{ typedef typename auto_ptr<T>::const_auto_ptr_is_not_allowed type; };
+
    
+
+
    
+There are other techniques to implement this helper class that might work
+better for different compliers (i.e. better diagnostics) and therefore I
+suggest defining its semantic behavior without mandating any specific
+implementation. IMO, and I didn't found any compiler that thinks otherwise,
+14.7.1/5 doesn't theoretically defeat the suggested technique but I suggest
+verifying this with core language experts.
+
    
+
+
    Further changes in standard text:
    
+
    Remove section 20.4.5.3
    
+
+
    Change 20.4.5/2 to read something like:
+Initializing auto_ptr<X> from const auto_ptr<Y> will result with unspecified
+ill-formed declaration that will require unspecified diagnostic.
    
+
+
    Change 20.4.5.1/4,5,6 to read:
    
+
+
    template<class Y> auto_ptr(auto_ptr<Y> const& a) throw();
    
+
     4 Requires: Y* can be implicitly converted to X*.
    
+
     5 Effects: Calls const_cast<auto_ptr<Y>&>(a).release().
    
+
     6 Postconditions: *this holds the pointer returned from a.release().
    
+
+
    Change 20.4.5.1/10
    
+
    template<class Y> auto_ptr& operator=(auto_ptr<Y> a) throw();
+
    
+
    
+10 Requires: Y* can be implicitly converted to X*. The expression delete
+get() is well formed.
+
    
+
+
    LWG TC DR #127 is obsolete.
    
+
+
    
+Notice that the copy constructor and copy assignment operator should remain
+as before and accept non-const auto_ptr& since they have effect on the form
+of the implicitly declared copy constructor and copy assignment operator of
+class that contains auto_ptr as member per 12.8/5,10:
+
    
+
    struct X {
+    // implicit X(X&)
+    // implicit X& operator=(X&)
+    auto_ptr<D> aptr_;
+};
+
    
+
+
    
+In most cases this indicates about sloppy programming but preserves the
+current auto_ptr behavior.
+
    
+
+
    
+Dave Abrahams encouraged me to suggest fallback implementation in case that
+my suggestion that involves removing of auto_ptr_ref will not be accepted.
+In this case removing the obsolete conversion member to auto_ptr<Y> and
+20.4.5.3/4,5 is still required in order to eliminate ambiguity in legal
+cases. The two constructors that I suggested will co exist with the current
+members but will make auto_ptr_ref obsolete in initialization contexts.
+auto_ptr_ref will be effective in assignment contexts as suggested in DR
+#127 and I can't see any serious exception safety issues in those cases
+(although it's possible to synthesize such). auto_ptr_ref<X> semantics will
+have to be revised to say that it strictly holds pointer of type X and not
+reference to an auto_ptr for the favor of cases in which auto_ptr_ref<Y> is
+constructed from auto_ptr<X> in which X is different from Y (i.e. assignment
+from r-value derived to base).
+
    
+
+
    [Redmond: punt for the moment. We haven't decided yet whether we
+  want to fix auto_ptr for C++-0x, or remove it and replace it with
+  move_ptr and unique_ptr.]
    
+
+
+
    [
+Oxford 2007: Recommend NAD.  We're just going to deprecate it.  It still works for simple use cases
+and people know how to deal with it.  Going forward unique_ptr is the recommended
+tool.
+]
    
+
+
+
    [
+2007-11-09: Reopened at the request of David Abrahams, Alisdair Meredith and Gabriel Dos Reis.
+]
    
+
+
+
    [
+2009-07 Frankfurt
+]
    
+
+
+
    
+This is a complicated issue, so we agreed to defer discussion until
+later in the week so that interested parties can read up on it.
+
    
+
+
    [
+209-10-04 Daniel adds:
+]
    
+
+
+
    
+
    
+I suggest to close this issue as NAD. The reasons are two-fold: First, the
+suggested proposed resolution uses no longer appropriate language means
+to solve this issue, which has the effect that the recommended resolution is
+another - but better - form of hack. Second, either following the suggested
+resolution or the now more natural alternative via the added member set
+
    
+
+
    template<class Y> auto_ptr(auto_ptr<Y>&&) throw();
+template<class Y> auto_ptr& operator=(auto_ptr<Y>&&) throw();
+
    
+
+
    
+would still have a non-zero probability to break user-code that actively
+references auto_ptr_ref. This risk seems to indicate that a
+decision which would not touch the current spec of auto_ptr at
+all (but deprecating it) and instead recommending to use
+unique_ptr for new code instead might have the best
+cost-benefit ratio. IMO the current solution of 1100 can
+be considered as an active user-support for this transition.
+
    
+
    
+
+
    [
+2009-10 Santa Cruz:
+]
    
+
+
+
    
+Mark as NAD. Alisdair will open a new issue (1247) with
+proposed wording to handle auto_ptr_ref.
+
    
+
+
+
+
    Proposed resolution:
    
+
    
+Change the synopsis in D.10.1 [auto.ptr]:
+
    
+
+
    namespace std { 
+  template <class Y> struct auto_ptr_ref {};
+
+  // exposition only
+  template <class T> struct constant_object;
+
+  // exposition only
+  template <class T>
+  struct cannot_transfer_ownership_from
+    : constant_object<T> {};
+
+  template <class X> class auto_ptr { 
+  public: 
+    typedef X element_type; 
+
+    // D.9.1.1 construct/copy/destroy: 
+    explicit auto_ptr(X* p =0) throw(); 
+    auto_ptr(auto_ptr&) throw(); 
+    template<class Y> auto_ptr(auto_ptr<Y> const&) throw(); 
+    auto_ptr& operator=(auto_ptr&) throw(); 
+    template<class Y> auto_ptr& operator=(auto_ptr<Y>&) throw();
+    auto_ptr& operator=(auto_ptr_ref<X> r) throw();
+    ~auto_ptr() throw(); 
+
+    // D.9.1.2 members: 
+    X& operator*() const throw();
+    X* operator->() const throw();
+    X* get() const throw();
+    X* release() throw();
+    void reset(X* p =0) throw();
+
+    // D.9.1.3 conversions:
+    auto_ptr(auto_ptr_ref<X>) throw();
+    template<class Y> operator auto_ptr_ref<Y>() throw();
+    template<class Y> operator auto_ptr<Y>() throw();
+
+    // exposition only
+    template<class U>
+    auto_ptr(U& rhs, typename cannot_transfer_ownership_from<U>::error = 0);
+  }; 
+
+  template <> class auto_ptr<void> 
+  { 
+  public: 
+    typedef void element_type; 
+  }; 
+
+}
+
    
+
+
    
+Remove D.10.1.3 [auto.ptr.conv].
+
    
+
+
    
+Change D.10.1 [auto.ptr], p3:
+
    
+
+
    
+The auto_ptr provides a semantics of strict ownership. An
+auto_ptr owns the object it holds a pointer to. Copying an
+auto_ptr copies the pointer and transfers ownership to the
+destination. If more than one auto_ptr owns the same object at
+the same time the behavior of the program is undefined. Templates
+constant_object and cannot_transfer_ownership_from,
+and the final constructor of auto_ptr are for exposition only.
+For any types X and Y, initializing
+auto_ptr<X> from const auto_ptr<Y> is
+ill-formed, diagnostic required. [Note: The uses of
+auto_ptr include providing temporary exception-safety for
+dynamically allocated memory, passing ownership of dynamically allocated
+memory to a function, and returning dynamically allocated memory from a
+function. auto_ptr does not meet the CopyConstructible
+and Assignable requirements for Standard Library container
+elements and thus instantiating a Standard Library container with an
+auto_ptr results in undefined behavior. -- end note]
+
    
+
+
    
+Change D.10.1.1 [auto.ptr.cons], p5:
+
    
+
+
    
+
    template<class Y> auto_ptr(auto_ptr<Y> const& a) throw();
+
    
+
    
+
    
+Requires: Y* can be implicitly converted to X*.
+
    
+
    
+Effects: Calls const_cast<auto_ptr<Y>&>(a).release().
+
    
+
    
+Postconditions: *this holds the pointer returned from a.release().
+
    
+
    
+
    
+
+
    
+Change D.10.1.1 [auto.ptr.cons], p10:
+
    
+
+
    
+
    template<class Y> auto_ptr& operator=(auto_ptr<Y>& a) throw();
+
    
+
    
+
    
+Requires: Y* can be implicitly converted to X*.
+The expression delete get() is well formed.
+
    
+
    
+Effects: Calls reset(a.release()).
+
    
+
    
+Returns: *this.
+
    
+
    
+
    
+
+
+
+
+
+
 
    
 
    466. basic_string ctor should prevent null pointer error
    
 
    Section: 21.4.1 [string.require] Status: NAD
@@ -8465,7 +9364,7 @@ corner cases.
 
 
    
 
    472. Missing "Returns" clause in std::equal_range
    
-
    Section: 25.5.3.3 [equal.range] Status: Dup
+
    Section: 25.4.3.3 [equal.range] Status: Dup
  Submitter: Prateek R Karandikar Opened: 2004-06-30  Last modified: 2006-12-30
    
 
    View all other issues in [equal.range].
    
 
    View all issues with Dup status.
    
@@ -8489,7 +9388,7 @@ There is no "Returns:" clause for std::equal_range, which returns non-void.
 
 
    
 
    476. Forward Iterator implied mutability
    
-
    Section: 24.2.4 [forward.iterators] Status: NAD
+
    Section: 24.2.3 [forward.iterators] Status: NAD
  Submitter: Dave Abrahams Opened: 2004-07-09  Last modified: 2007-01-15
    
 
    View all other issues in [forward.iterators].
    
 
    View all issues with NAD status.
    
@@ -8529,7 +9428,7 @@ overhaul.)
    
 
 
    
 
    477. Operator-> for const forward iterators
    
-
    Section: 24.2.4 [forward.iterators] Status: Dup
+
    Section: 24.2.3 [forward.iterators] Status: Dup
  Submitter: Dave Abrahams Opened: 2004-07-11  Last modified: 2007-01-15
    
 
    View all other issues in [forward.iterators].
    
 
    View all issues with Dup status.
    
@@ -8587,7 +9486,7 @@ as the first line.
    
 
    View other active issues in [container.requirements].
    
 
    View all other issues in [container.requirements].
    
 
    View all issues with Dup status.
    
-
    Duplicate of: 580
    
+
    Duplicate of: 580
    
 
    Discussion:
    
 
    Nothing in the standard appears to make this program ill-formed:
    
 
@@ -8696,7 +9595,7 @@ nonvirtual destructors.
    
 
 
    
 
    481. unique's effects on the range [result, last)
    
-
    Section: 25.4.9 [alg.unique] Status: NAD
+
    Section: 25.3.9 [alg.unique] Status: NAD
  Submitter: Andrew Koenig Opened: 2004-08-30  Last modified: 2006-12-27
    
 
    View all other issues in [alg.unique].
    
 
    View all issues with NAD status.
    
@@ -8733,7 +9632,7 @@ explicit, but it's hard to think that's a major problem.
    
 
 
    
 
    482. Swapping pairs
    
-
    Section: 20.3.3 [pairs], 20.5 [tuple] Status: NAD Editorial
+
    Section: 20.3.4 [pairs], 20.5 [tuple] Status: NAD Editorial
  Submitter: Andrew Koenig Opened: 2004-09-14  Last modified: 2007-05-06
    
 
    View other active issues in [pairs].
    
 
    View all other issues in [pairs].
    
@@ -8776,7 +9675,7 @@ Recommend NAD, fixed by
 
 
    
 
    483. Heterogeneous equality and EqualityComparable
    
-
    Section: 25.3 [alg.nonmodifying], 25.4 [alg.modifying.operations] Status: Dup
+
    Section: 25.2 [alg.nonmodifying], 25.3 [alg.modifying.operations] Status: Dup
  Submitter: Peter Dimov Opened: 2004-09-20  Last modified: 2007-01-15
    
 
    View all issues with Dup status.
    
 
    Duplicate of: 283
    
@@ -8879,9 +9778,97 @@ operator that takes a T, or a T may be convertible to the type of *i.
 
 
 
+
    
+
    484. Convertible to T
    
+
    Section: 24.2.1 [input.iterators] Status: NAD Future
+ Submitter: Chris Jefferson Opened: 2004-09-16  Last modified: 2009-10-26
    
+
    View all other issues in [input.iterators].
    
+
    View all issues with NAD Future status.
    
+
    Discussion:
    
+
    From comp.std.c++:
    
+
+
    
+I note that given an input iterator a for type T, 
+then *a only has to be "convertable to T", not actually of type T.
+
    
+
+
    Firstly, I can't seem to find an exact definition of "convertable to T". 
+While I assume it is the obvious definition (an implicit conversion), I 
+can't find an exact definition. Is there one?
    
+
+
    Slightly more worryingly, there doesn't seem to be any restriction on 
+the this type, other than it is "convertable to T". Consider two input 
+iterators a and b. I would personally assume that most people would 
+expect *a==*b would perform T(*a)==T(*b), however it doesn't seem that 
+the standard requires that, and that whatever type *a is (call it U) 
+could have == defined on it with totally different symantics and still 
+be a valid inputer iterator.
    
+
+
    Is this a correct reading? When using input iterators should I write 
+T(*a) all over the place to be sure that the object i'm using is the 
+class I expect?
    
+
+
    This is especially a nuisance for operations that are defined to be
+  "convertible to bool".  (This is probably allowed so that
+  implementations could return say an int and avoid an unnessary
+  conversion. However all implementations I have seen simply return a
+  bool anyway.  Typical implemtations of STL algorithms just write
+  things like while(a!=b && *a!=0).  But strictly
+  speaking, there are lots of types that are convertible to T but
+  that also overload the appropriate operators so this doesn't behave
+  as expected.
    
+
+
    If we want to make code like this legal (which most people seem to
+  expect), then we'll need to tighten up what we mean by "convertible
+  to T".
    
+
+
    [Lillehammer: The first part is NAD, since "convertible" is
+ well-defined in core. The second part is basically about pathological
+ overloads. It's a minor problem but a real one. So leave open for
+ now, hope we solve it as part of iterator redesign.]
    
+
+
+
    [
+2009-07-28 Reopened by Alisdair.  No longer solved by concepts.
+]
    
+
+
+
    [
+2009-10 Santa Cruz:
+]
    
+
+
+
    
+Mark as NAD Future. We agree there's an issue, but there is no
+proposed solution at this time and this will be solved by concepts in
+the future.
+
    
+
+
+
+
    Proposed resolution:
    
+
+
+
    Rationale:
    
+
    [
+San Francisco:
+]
    
+
+
+
    
+Solved by
+N2758.
+
    
+
+
+
+
+
+
+
 
    
 
    486. min/max CopyConstructible requirement is too strict
    
-
    Section: 25.5.7 [alg.min.max] Status: Dup
+
    Section: 25.4.7 [alg.min.max] Status: Dup
  Submitter: Dave Abrahams Opened: 2004-10-13  Last modified: 2006-12-30
    
 
    View all other issues in [alg.min.max].
    
 
    View all issues with Dup status.
    
@@ -8904,9 +9891,8 @@ copy T.
    
 
 
    
 
    487. Allocator::construct is too limiting
    
-
    Section: X [allocator.requirements] Status: NAD
+
    Section: 20.2.2 [allocator.requirements] Status: NAD
  Submitter: Dhruv Matani Opened: 2004-10-17  Last modified: 2006-12-30
    
-
    View other active issues in [allocator.requirements].
    
 
    View all other issues in [allocator.requirements].
    
 
    View all issues with NAD status.
    
 
    Discussion:
    
@@ -8949,7 +9935,7 @@ be called! Doesn't that sound great?
 
 
    
 
    489. std::remove / std::remove_if wrongly specified
    
-
    Section: 25.4.8 [alg.remove] Status: NAD
+
    Section: 25.3.8 [alg.remove] Status: NAD
  Submitter: Thomas Mang Opened: 2004-12-12  Last modified: 2006-12-27
    
 
    View all other issues in [alg.remove].
    
 
    View all issues with NAD status.
    
@@ -9148,7 +10134,7 @@ ISO/IEC 14882:2003.
 
 
    
 
    490. std::unique wrongly specified
    
-
    Section: 25.4.9 [alg.unique] Status: NAD
+
    Section: 25.3.9 [alg.unique] Status: NAD
  Submitter: Thomas Mang Opened: 2004-12-12  Last modified: 2006-12-27
    
 
    View all other issues in [alg.unique].
    
 
    View all issues with NAD status.
    
@@ -9401,6 +10387,7 @@ change, so there is no real-world harm here.
    
 
    491. std::list<>::unique incorrectly specified
    
 
    Section: 23.3.4.4 [list.ops] Status: NAD
  Submitter: Thomas Mang Opened: 2004-12-12  Last modified: 2007-02-19
    
+
    View other active issues in [list.ops].
    
 
    View all other issues in [list.ops].
    
 
    View all issues with NAD status.
    
 
    Discussion:
    
@@ -9818,7 +10805,7 @@ it doesn't cover. Bill will provide wording.]
    
 
 
    
 
    493. Undefined Expression in Input Iterator Note Title
    
-
    Section: 24.2.2 [input.iterators] Status: NAD
+
    Section: 24.2.1 [input.iterators] Status: NAD
  Submitter: Chris Jefferson Opened: 2004-12-13  Last modified: 2006-12-27
    
 
    View all other issues in [input.iterators].
    
 
    View all issues with NAD status.
    
@@ -9860,6 +10847,7 @@ not guarantee the substitution property or referential transparency).
    
 
    494. Wrong runtime complexity for associative container's insert and delete
    
 
    Section: 23.2.4 [associative.reqmts] Status: NAD
  Submitter: Hans B os Opened: 2004-12-19  Last modified: 2006-12-27
    
+
    View other active issues in [associative.reqmts].
    
 
    View all other issues in [associative.reqmts].
    
 
    View all issues with NAD status.
    
 
    Discussion:
    
@@ -9916,7 +10904,7 @@ last) and insert(first, last).
    
 
 
    
 
    499. Std. doesn't seem to require stable_sort() to be stable!
    
-
    Section: 25.5.1.2 [stable.sort] Status: NAD Editorial
+
    Section: 25.4.1.2 [stable.sort] Status: NAD Editorial
  Submitter: Prateek Karandikar Opened: 2005-04-12  Last modified: 2008-03-13
    
 
    View all issues with NAD Editorial status.
    
 
    Discussion:
    
@@ -11071,6 +12059,7 @@ in the WP.
 
    526. Is it undefined if a function in the standard changes in parameters?
    
 
    Section: 23.2.3 [sequence.reqmts] Status: NAD
  Submitter: Chris Jefferson Opened: 2005-09-14  Last modified: 2008-03-13
    
+
    View other active issues in [sequence.reqmts].
    
 
    View all other issues in [sequence.reqmts].
    
 
    View all issues with NAD status.
    
 
    Discussion:
    
@@ -11205,7 +12194,7 @@ doesn't give permission for it not to work.
    • doesn't give permission for it not to work.
  • vector::insert(iter, iter, iter) is not required to work because 23.2.3 [sequence.reqmts], p4 says so.
    • -
  • copy has to work, except where 25.4.1 [alg.copy] says +
  • copy has to work, except where 25.3.1 [alg.copy] says it doesn't have to work. While a language lawyer can tear this wording apart, it is felt that the wording is not prone to accidental interpretation.
  • The current working draft provide exceptions for the unordered associative @@ -11387,6 +12376,110 @@ Alan provided the survey +
    +

    532. Tuple comparison

    +

    Section: 20.5.2.7 [tuple.rel], TR1 6.1.3.5 [tr.tuple.rel] Status: NAD Future + Submitter: David Abrahams Opened: 2005-11-29 Last modified: 2009-10-24

    +

    View all other issues in [tuple.rel].

    +

    View all issues with NAD Future status.

    +

    Duplicate of: 348

    +

    Discussion:

    +

    +Where possible, tuple comparison operators <,<=,=>, and > ought to be +defined in terms of std::less rather than operator<, in order to +support comparison of tuples of pointers. +

    + +

    [ +2009-07-28 Reopened by Alisdair. No longer solved by concepts. +]

    + + +

    [ +2009-10 Santa Cruz: +]

    + + +
    +

    +If we solve this for tuple we would have to solve it for pair +algorithms, etc. It is too late to do that at this time. Move to NAD Future. +

    +
    + + + +

    Proposed resolution:

    +

    +change 6.1.3.5/5 from: +

    + +

    + Returns: The result of a lexicographical comparison between t and + u. The result is defined as: (bool)(get<0>(t) < get<0>(u)) || + (!(bool)(get<0>(u) < get<0>(t)) && ttail < utail), where rtail for + some tuple r is a tuple containing all but the first element of + r. For any two zero-length tuples e and f, e < f returns false. +

    + +

    +to: +

    + +
    +

    + Returns: The result of a lexicographical comparison between t and + u. For any two zero-length tuples e and f, e < f returns false. + Otherwise, the result is defined as: cmp( get<0>(t), get<0>(u)) || + (!cmp(get<0>(u), get<0>(t)) && ttail < utail), where rtail for some + tuple r is a tuple containing all but the first element of r, and + cmp(x,y) is an unspecified function template defined as follows. +

    +

    + Where T is the type of x and U is the type of y: +

    + +

    + if T and U are pointer types and T is convertible to U, returns + less<U>()(x,y) +

    + +

    + otherwise, if T and U are pointer types, returns less<T>()(x,y) +

    + +

    + otherwise, returns (bool)(x < y) +

    +
    + +

    [ +Berlin: This issue is much bigger than just tuple (pair, containers, +algorithms). Dietmar will survey and work up proposed wording. +]

    + + + + +

    Rationale:

    +

    +Recommend NAD. This will be fixed with the next revision of concepts. +

    + +

    [ +San Francisco: +]

    + + +
    +Solved by +N2770. +
    + + + + +

    536. Container iterator constructor and explicit convertibility

    Section: 23.2 [container.requirements] Status: Dup @@ -11463,7 +12556,6 @@ Berlin: Some support, not universal, for respecting the explicit qualifier.

    544. minor NULL problems in C.2

    Section: C.2 [diff.library] Status: NAD Editorial Submitter: Martin Sebor Opened: 2005-11-25 Last modified: 2007-04-24

    -

    View other active issues in [diff.library].

    View all other issues in [diff.library].

    View all issues with NAD Editorial status.

    Discussion:

    @@ -11884,7 +12976,7 @@ may not be unique if intmax_t==_longlong.

    558. lib.input.iterators Defect

    -

    Section: 24.2.2 [input.iterators] Status: NAD Editorial +

    Section: 24.2.1 [input.iterators] Status: NAD Editorial Submitter: David Abrahams Opened: 2006-02-09 Last modified: 2007-04-24

    View all other issues in [input.iterators].

    View all issues with NAD Editorial status.

    @@ -11932,9 +13024,8 @@ Portland: Editorial.

    560. User-defined allocators without default constructor

    -

    Section: X [allocator.requirements] Status: NAD +

    Section: 20.2.2 [allocator.requirements] Status: NAD Submitter: Sergey P. Derevyago Opened: 2006-02-17 Last modified: 2007-04-18

    -

    View other active issues in [allocator.requirements].

    View all other issues in [allocator.requirements].

    View all issues with NAD status.

    Discussion:

    @@ -12440,9 +13531,186 @@ uses depend on the iterator being returned. +
    +

    580. unused allocator members

    +

    Section: 23.2.1 [container.requirements.general] Status: NAD Editorial + Submitter: Martin Sebor Opened: 2006-06-14 Last modified: 2009-10-26

    +

    View other active issues in [container.requirements.general].

    +

    View all other issues in [container.requirements.general].

    +

    View all issues with NAD Editorial status.

    +

    Duplicate of: 479

    +

    Discussion:

    +

    + +C++ Standard Library templates that take an allocator as an argument +are required to call the allocate() and +deallocate() members of the allocator object to obtain +storage. However, they do not appear to be required to call any other +allocator members such as construct(), +destroy(), address(), and +max_size(). This makes these allocator members less than +useful in portable programs. + +

    +

    + +It's unclear to me whether the absence of the requirement to use these +allocator members is an unintentional omission or a deliberate +choice. However, since the functions exist in the standard allocator +and since they are required to be provided by any user-defined +allocator I believe the standard ought to be clarified to explictly +specify whether programs should or should not be able to rely on +standard containers calling the functions. + +

    +

    + +I propose that all containers be required to make use of these +functions. + +

    +

    [ +Batavia: We support this resolution. Martin to provide wording. +]

    + +

    [ +pre-Oxford: Martin provided wording. +]

    + + +

    [ +2009-04-28 Pablo adds: +]

    + + +
    +N2554 +(scoped allocators), +N2768 +(allocator concepts), and +N2810 +(allocator defects), address all of these points EXCEPT max_size(). +So, I would add a note to that affect and re-class the defect as belonging +to section 23.2.1 [container.requirements.general]. +
    + +

    [ +2009-07 Frankfurt +]

    + + +
    +The comment in the description of this issue that this "would be" +rendered editorial by the adoption of N2257 is confusing. It appears +that N2257 was never adopted. +
    + +

    [ +2009-10 Santa Cruz: +]

    + + +
    +NAD Editorial. Addressed by +N2982. +
    + + + +

    Proposed resolution:

    +

    + +Specifically, I propose to change 23.2 [container.requirements], +p9 as follows: + +

    +
    +

    +-9- Copy constructors for all container types defined in this clause +that are parametrized on Allocator copy +anthe allocator argument from their respective +first parameters. + +All other constructors for these container types take an +const Allocator& argument (20.1.6), an +allocator whose value_type is the same as the container's +value_type. + +A copy of this argument isshall be used for any +memory allocation and deallocation performed, +by these constructors and by all member functions, during +the lifetime of each container object. Allocation shall be +performed "as if" by calling the allocate() member +function on a copy of the allocator object of the appropriate type +New Footnote), and deallocation "as if" by calling +deallocate() on a copy of the same allocator object of +the corresponding type. + +A copy of this argument shall also be used to construct and +destroy objects whose lifetime is managed by the container, including +but not limited to those of the container's value_type, +and to obtain their address. All objects residing in storage +allocated by a container's allocator shall be constructed "as if" by +calling the construct() member function on a copy of the +allocator object of the appropriate type. The same objects shall be +destroyed "as if" by calling destroy() on a copy of the +same allocator object of the same type. The address of such objects +shall be obtained "as if" by calling the address() member +function on a copy of the allocator object of the appropriate +type. + +Finally, a copy of this argument shall be used by its container +object to determine the maximum number of objects of the container's +value_type the container may store at the same time. The +container member function max_size() obtains this number +from the value returned by a call to +get_allocator().max_size(). + +In all container types defined in this clause that are +parametrized on Allocator, the member +get_allocator() returns a copy of the +Allocator object used to construct the +container.258) +

    +

    +New Footnote: This type may be different from Allocator: +it may be derived from Allocator via +Allocator::rebind<U>::other for the appropriate +type U. +

    +
    +

    + +The proposed wording seems cumbersome but I couldn't think of a better +way to describe the requirement that containers use their +Allocator to manage only objects (regardless of their +type) that persist over their lifetimes and not, for example, +temporaries created on the stack. That is, containers shouldn't be +required to call Allocator::construct(Allocator::allocate(1), +elem) just to construct a temporary copy of an element, or +Allocator::destroy(Allocator::address(temp), 1) to +destroy temporaries. + +

    + + +

    [ +Howard: This same paragraph will need some work to accommodate 431. +]

    + + +

    [ +post Oxford: This would be rendered NAD Editorial by acceptance of +N2257. +]

    + + + + +

    582. specialized algorithms and volatile storage

    -

    Section: 20.8.8.2 [uninitialized.copy] Status: NAD +

    Section: 20.8.13.2 [uninitialized.copy] Status: NAD Submitter: Martin Sebor Opened: 2006-06-14 Last modified: 2009-07-15

    View all other issues in [uninitialized.copy].

    View all issues with NAD status.

    @@ -12494,7 +13762,7 @@ possible editorial change would be to put my previous sentence into a non-normative note.

    -Note that the three sections starting with 20.8.8.2 [uninitialized.copy] do not +Note that the three sections starting with 20.8.13.2 [uninitialized.copy] do not yet have concepts. Here's a first crack at the first one: 

    template <InputIterator InIter, OutputIterator OutIter>
@@ -12863,7 +14131,7 @@ Proposed Disposition: Open
 
 
    
 
    587. iststream ctor missing description
    
-
    Section: D.7.2.1 [depr.istrstream.cons] Status: NAD Editorial
+
    Section: D.8.2.1 [depr.istrstream.cons] Status: NAD Editorial
  Submitter: Martin Sebor Opened: 2006-06-22  Last modified: 2007-05-11
    
 
    View all issues with NAD Editorial status.
    
 
    Discussion:
    
@@ -12894,11 +14162,216 @@ post Oxford: Noted that it is already fixed in
 
 
 
+
    
+
    588. requirements on zero sized tr1::arrays and other details
    
+
    Section: 23.3.1 [array] Status: NAD
+ Submitter: Gennaro Prota Opened: 2006-07-18  Last modified: 2009-10-20
    
+
    View all other issues in [array].
    
+
    View all issues with NAD status.
    
+
    Discussion:
    
+
    
+The wording used for section 23.2.1 [lib.array] seems to be subtly
+ambiguous about zero sized arrays (N==0). Specifically:
+
    
+
    
+* "An instance of array<T, N> stores N elements of type T, so that
+[...]"
+
    
+
    
+Does this imply that a zero sized array object stores 0 elements, i.e.
+that it cannot store any element of type T? The next point clarifies
+the rationale behind this question, basically how to implement begin()
+and end():
+
    
+
    
+* 23.2.1.5 [lib.array.zero], p2: "In the case that N == 0, begin() ==
+end() == unique value."
+
    
+
    
+What does "unique" mean in this context? Let's consider the following
+possible implementations, all relying on a partial specialization:
+
    
+
    a)
+    template< typename T >
+    class array< T, 0 > {
+    
+        ....
+
+        iterator begin()
+        { return iterator( reinterpret_cast< T * >( this ) ); }
+        ....
+
+    };
+
    
+
    
+This has been used in boost, probably intending that the return value
+had to be unique to the specific array object and that array couldn't
+store any T. Note that, besides relying on a reinterpret_cast, has
+(more than potential) alignment problems.
+
    
+
    b)
+    template< typename T >
+    class array< T, 0 > {
+    
+        T t;
+
+        iterator begin()
+        { return iterator( &t ); }
+        ....
+
+    };
+
    
+
    
+This provides a value which is unique to the object and to the type of
+the array, but requires storing a T. Also, it would allow the user to
+mistakenly provide an initializer list with one element.
+
    
+
    
+A slight variant could be returning *the* null pointer of type T
+
    
+
        return static_cast<T*>(0);
+
    
+
    
+In this case the value would be unique to the type array<T, 0> but not
+to the objects (all objects of type array<T, 0> with the same value
+for T would yield the same pointer value).
+
    
+
    
+Furthermore this is inconsistent with what the standard requires from
+allocation functions (see library issue 9).
+
    
+
    
+c) same as above but with t being a static data member; again, the
+value would be unique to the type, not to the object.
+
    
+
    
+d) to avoid storing a T *directly* while disallowing the possibility
+to use a one-element initializer list a non-aggregate nested class
+could be defined
+
    
+
        struct holder { holder() {} T t; } h;
+
    
+
    
+and then begin be defined as
+
    
+
     iterator begin() { return &h.t; }
+
    
+
    
+But then, it's arguable whether the array stores a T or not.
+Indirectly it does.
+
    
+
    
+-----------------------------------------------------
+
    
+
    
+Now, on different issues:
+
    
+
    
+* what's the effect of calling assign(T&) on a zero-sized array? There
+seems to be only mention of front() and back(), in 23.2.1 [lib.array]
+p4 (I would also suggest to move that bullet to section 23.2.1.5
+[lib.array.zero], for locality of reference)
+
    
+
    
+* (minor) the opening paragraph of 23.2.1 [lib.array] wording is a bit
+inconsistent with that of other sequences: that's not a problem in
+itself, but compare it for instance with "A vector is a kind of
+sequence that supports random access iterators"; though the intent is
+obvious one might argue that the wording used for arrays doesn't tell
+what an array is, and relies on the reader to infer that it is what
+the <array> header defines.
+
    
+
    
+* it would be desiderable to have a static const data member of type
+std::size_t, with value N, for usage as integral constant expression
+
    
+
    
+* section 23.1 [lib.container.requirements] seem not to consider
+fixed-size containers at all, as it says: "[containers] control
+allocation and deallocation of these objects [the contained objects]
+through constructors, destructors, *insert and erase* operations"
+
    
+
    
+* max_size() isn't specified: the result is obvious but, technically,
+it relies on table 80: "size() of the largest possible container"
+which, again, doesn't seem to consider fixed size containers
+
    
+
+
    [
+2009-05-29 Daniel adds:
+]
    
+
+
+
    
+
      
+
    1. 
+
      
+star bullet 1 ("what's the effect of calling assign(T&) on a
+zero-sized array?[..]");
+
      
+
      
+assign has been renamed to fill and the semantic of fill is now
+defined in terms of
+the free algorithm fill_n, which is well-defined for this situation.
+
      
+
      2. 
+
    2. 
+
      
+star bullet 3 ("it would be desiderable to have a static const data
+member..."):
+
      
+
      
+It seems that tuple_size<array<T, N> >::value as of 23.3.1.7 [array.tuple] does
+provide this functionality now.
+
      
+
      3. 
+
    
+
    
+
+
    [
+2009-07 Frankfurt
+]
    
+
+
+
    
+
    
+Alisdair to address by the next meeting, or declare NAD.
+
    
+
    
+Moved to Tentatively NAD.
+
    
+
    
+
+
    [
+2009 Santa Cruz:
+]
    
+
+
+
    
+Moved to NAD.
+
    
+
+
+
+
    Proposed resolution:
    
+
    
+
    
+
+
+
    [
+Kona (2007): requirements on zero sized tr1::arrays and other details
+Issue 617: std::array is a sequence that doesn't satisfy the sequence
+requirements? Alisdair will prepare a paper. Proposed Disposition: Open
+]
    
+
+
+
+
+
 
    
 
    590. Type traits implementation latitude should be removed for C++0x
    
 
    Section: 20.6 [meta], TR1 4.9 [tr.meta.req] Status: NAD Editorial
  Submitter: Beman Dawes Opened: 2006-08-10  Last modified: 2007-05-11
    
-
    View other active issues in [meta].
    
 
    View all other issues in [meta].
    
 
    View all issues with NAD Editorial status.
    
 
    Discussion:
    
@@ -13364,6 +14837,135 @@ Recommend NAD, editorial.  Send to Pete.
 
 
 
+
    
+
    617. std::array is a sequence that doesn't satisfy the sequence requirements?
    
+
    Section: 23.3.1 [array] Status: NAD
+ Submitter: Bo Persson Opened: 2006-12-30  Last modified: 2009-10-20
    
+
    View all other issues in [array].
    
+
    View all issues with NAD status.
    
+
    Discussion:
    
+
    
+The <array> header is given under 23.3 [sequences].
+23.3.1 [array]/paragraph 3 says:
+
    
+
    
+"Unless otherwise specified, all array operations are as described in
+23.2 [container.requirements]".
+
    
+
    
+However, array isn't mentioned at all in section 23.2 [container.requirements].
+In particular, Table 82 "Sequence requirements" lists several operations (insert, erase, clear) 
+that std::array does not have in 23.3.1 [array].
+
    
+
    
+Also, Table 83 "Optional sequence operations" lists several operations that 
+std::array does have, but array isn't mentioned.
+
    
+
+
    [
+2009-07 Frankfurt
+]
    
+
+
+
    
+
    
+The real issue seems to be different than what is described here.
+Non-normative text says that std::array is a sequence container, but
+there is disagreement about what that really means. There are two
+possible interpretations:
+
    
+
      
+
    1. 
+a sequence container is one that satisfies all sequence container requirements
+
      2. 
+
    2. 
+a sequence container is one that satisfies some of the sequence
+container requirements. Any operation that the container supports is
+specified by one or more sequence container requirements, unless that
+operation is specifically singled out and defined alongside the
+description of the container itself.
+
      3. 
+
    
+
    
+Move to Tentatively NAD.
+
    
+
    
+
+
    [
+2009-07-15 Loďc Joly adds:
+]
    
+
+
+
    
+
    
+The section 23.2.3 [sequence.reqmts]/1 states that array is a sequence. 23.2.3 [sequence.reqmts]/3
+introduces table 83, named Sequence container requirements. This seems
+to me to be defining the requirements for all sequences. However, array
+does not follow all of this requirements (this can be read in the array
+specific section, for the standard is currently inconsistent).
+
    
+
+
    
+Proposed resolution 1 (minimal change): 
+
    
+
    
+
    
+Say that array is a container, that in addition follows only some of the
+sequence requirements, as described in the array section:
+
    
+
+
    
+The library provides five three basic kinds of sequence containers: array,
+vector, 
+forward_list, list, and deque. In addition, array
+and forward_list follows some of the requirements 
+of sequences, as described in their respective sections.
+
    
+
+
    
+
+
    
+Proposed resolution 2 (most descriptive description, no full wording provided): 
+
    
+
    
+Introduce the notion of a Fixed Size Sequence, with it requirement table
+that would be a subset of the current Sequence container. array would be
+the only Fixed Size Sequence (but dynarray is in the queue for TR2).
+Sequence requirements would now be requirements in addition to Fixed
+Size Sequence requirements (it is currently in addition to container).
+
    
+
    
+
+
    [
+2009-07 Frankfurt:
+]
    
+
+
+
    
+Move to NAD Editorial
+
    
+
+
    [
+2009 Santa Cruz:
+]
    
+
+
+
    
+This will require a lot of reorganization. Editor doesn't think this is really
+an issue, since the description of array can be considered as overriding
+what's specified about sequences. Move to NAD.
+
    
+
+
+
+
    Proposed resolution:
    
+
    
+
    
+
+
+
+
+
 
    
 
    626. new Remark clauses not documented
    
 
    Section: 17.5.1.4 [structure.specifications] Status: NAD Editorial
@@ -13539,12 +15141,12 @@ Fixed by paper N2923.
 
 
    
 
    633. Return clause mentions undefined "type()"
    
-
    Section: 20.7.16.2.5 [func.wrap.func.targ] Status: NAD Editorial
+
    Section: 20.7.15.2.5 [func.wrap.func.targ] Status: NAD Editorial
  Submitter: Daniel Krügler Opened: 2007-02-03  Last modified: 2007-07-02
    
 
    View all issues with NAD Editorial status.
    
 
    Discussion:
    
 
    
-20.7.16.2.5 [func.wrap.func.targ], p4 says:
+20.7.15.2.5 [func.wrap.func.targ], p4 says:
 
    
 
    
 Returns: If type() == typeid(T), a pointer to the stored
@@ -13560,7 +15162,7 @@ function type() in class template function nor in the global or
 
  • 
 Assuming that type should have been target_type(),
 this description would lead to false results, if T = cv
-void due to returns clause 20.7.16.2.5 [func.wrap.func.targ], p1.
+void due to returns clause 20.7.15.2.5 [func.wrap.func.targ], p1.
 
    • 
 
 
@@ -13568,7 +15170,7 @@ void due to returns clause 20.7.16.2.5 [func.wrap.func.targ], p1.
 
 
    Proposed resolution:
    
 
    
-Change 20.7.16.2.5 [func.wrap.func.targ], p4:
+Change 20.7.15.2.5 [func.wrap.func.targ], p4:
 
    
 
 
    
@@ -13587,6 +15189,132 @@ Pete: Agreed. It's editorial, so I'll fix it.
 
 
 
+
    
+
    635. domain of allocator::address
    
+
    Section: 20.2.2 [allocator.requirements] Status: NAD Editorial
+ Submitter: Howard Hinnant Opened: 2007-02-08  Last modified: 2009-10-26
    
+
    View all other issues in [allocator.requirements].
    
+
    View all issues with NAD Editorial status.
    
+
    Discussion:
    
+
    
+The table of allocator requirements in 20.2.2 [allocator.requirements] describes
+allocator::address as:
+
    
+
    a.address(r)
+a.address(s)
+
    
+
    
+where r and s are described as:
+
    
+
    
+a value of type X::reference obtained by the expression *p. 
+
    
+
+
    
+and p is 
+
    
+
+
    
+a value of type X::pointer, obtained by calling a1.allocate, 
+where a1 == a
+
    
+
+
    
+This all implies that to get the address of some value of type T that
+value must have been allocated by this allocator or a copy of it.
+
    
+
+
    
+However sometimes container code needs to compare the address of an external value of
+type T with an internal value.  For example list::remove(const T& t)
+may want to compare the address of the external value t with that of a value
+stored within the list.  Similarly vector or deque insert may
+want to make similar comparisons (to check for self-referencing calls).
+
    
+
+
    
+Mandating that allocator::address can only be called for values which the
+allocator allocated seems overly restrictive.
+
    
+
+
    [
+post San Francisco:
+]
    
+
+
+
    
+Pablo recommends NAD Editorial, solved by
+N2768.
+
    
+
+
    [
+2009-04-28 Pablo adds:
+]
    
+
+
+
    
+Tentatively-ready NAD Editorial as fixed by
+N2768.
+
    
+
+
    [
+2009-07 Frankfurt
+]
    
+
+
+
    
+Fixed by N2768.
+
    
+
+
    [
+2009-07-28 Reopened by Alisdair.  No longer solved by concepts.
+]
    
+
+
+
    [
+2009-10 Santa Cruz:
+]
    
+
+
+
    
+NAD Editorial.  Addressed by
+N2982.
+
    
+
+
+
+
    Proposed resolution:
    
+
    
+Change 20.2.2 [allocator.requirements]:
+
    
+
+
    
+
    
+r : a value of type X::reference obtained by the expression *p.
+
    
+
    
+s : a value of type X::const_reference obtained by the 
+expression *q or by conversion from a value r.
+
    
+
    
+
+
    [
+post Oxford:  This would be rendered NAD Editorial by acceptance of
+N2257.
+]
    
+
+
+
    [
+Kona (2007):  This issue is section 8 of N2387.  There was some discussion of it but
+no resolution to this issue was recorded.  Moved to Open.
+]
    
+
+
+
+
+
+
+
 
    
 
    636. 26.5.2.3 valarray::operator[]
    
 
    Section: 26.6.2.3 [valarray.access] Status: NAD Editorial
@@ -13903,13 +15631,13 @@ In 27.9.1.13 [ofstream.members], remove footnote:
 
 
    
 
    644. Possible typos in 'function' description
    
-
    Section: 20.7.16.2 [func.wrap.func] Status: NAD
+
    Section: 20.7.15.2 [func.wrap.func] Status: NAD
  Submitter: Bo Persson Opened: 2007-02-25  Last modified: 2009-07-13
    
 
    View all other issues in [func.wrap.func].
    
 
    View all issues with NAD status.
    
 
    Discussion:
    
 
    
-20.7.16.2 [func.wrap.func]
+20.7.15.2 [func.wrap.func]
 
    
 
    
 The note in paragraph 2 refers to 'undefined void operators', while the
@@ -13935,7 +15663,7 @@ type of these deleted functions to be?
 
    
 
    
 I suggest harmonizing this issue with similar classes. E.g. in
-20.8.10.3 [util.smartptr.weak] bool return values for
+20.8.15.3 [util.smartptr.weak] bool return values for
 
    
 
    template <class Y> bool operator<(weak_ptr<Y> const&) const = delete;
 template <class Y> bool operator<=(weak_ptr<Y> const&) const = delete;
@@ -13973,19 +15701,19 @@ Move to NAD.
 
 
    Proposed resolution:
    
 
    
-Change 20.7.16.2 [func.wrap.func]
+Change 20.7.15.2 [func.wrap.func]
 
    
 
 
    ...
 private:
-   // 20.7.16.2 [func.wrap.func], undefined operators:
+   // 20.7.15.2 [func.wrap.func], undefined operators:
    template<class Function2> bool void operator==(const function<Function2>&);
    template<class Function2> bool void operator!=(const function<Function2>&);
 };
 
    
 
 
    
-Change 20.7.16.2 [func.wrap.func]
+Change 20.7.15.2 [func.wrap.func]
 
    
 
 
    template<class Function2> bool void operator==(const function<Function2>&);
@@ -14555,7 +16283,7 @@ void operator!=(const function<Function1>&, const function<Function
 
    
 which are nowhere described. I assume that they are relicts before the
 corresponding two private and undefined member templates in the function
-template (see 20.7.16.2 [func.wrap.func] and  [func.wrap.func.undef]) have been introduced. The original free
+template (see 20.7.15.2 [func.wrap.func] and  [func.wrap.func.undef]) have been introduced. The original free
 function templates should be removed, because using an undefined entity
 would lead to an ODR violation of the user.
 
    
@@ -14766,7 +16494,6 @@ identified, and big-O notation always involves constant factors.
 
    667. money_get's widened minus sign
    
 
    Section: 22.4.6.1.2 [locale.money.get.virtuals] Status: NAD
  Submitter: Thomas Plum Opened: 2007-04-16  Last modified: 2009-07-13
    
-
    View other active issues in [locale.money.get.virtuals].
    
 
    View all other issues in [locale.money.get.virtuals].
    
 
    View all issues with NAD status.
    
 
    Discussion:
    
@@ -14841,11 +16568,220 @@ Move to NAD.
 
 
 
+
    
+
    668. money_get's empty minus sign
    
+
    Section: 22.4.6.1.2 [locale.money.get.virtuals] Status: NAD
+ Submitter: Thomas Plum Opened: 2007-04-16  Last modified: 2009-10-21
    
+
    View all other issues in [locale.money.get.virtuals].
    
+
    View all issues with NAD status.
    
+
    Discussion:
    
+
    
+22.4.6.1.2 [locale.money.get.virtuals], para 3 says:
+
    
+
+
    
+If pos or neg is empty, the sign component is
+optional, and if no sign is detected, the result is given the sign
+that corresponds to the source of the empty string.
+
    
+
+
    
+The following objection has been raised:
+
    
+
+
    
+A negative_sign of "" means "there is no
+way to write a negative sign" not "any null sequence is a negative
+sign, so it's always there when you look for it".
+
    
+
+
    
+[Plum ref _222612Y32]
+
    
+
+
    [
+Kona (2007): Bill to provide proposed wording and interpretation of existing wording.
+]
    
+
+
+
    
+Related to 669.
+
    
+
+
    [
+2009-05-17 Howard adds:
+]
    
+
+
+
    
+
    
+I disagree that a negative_sign of "" means "there is no
+way to
+write a negative sign". The meaning requires the sentences of
+22.4.6.1.2 [locale.money.get.virtuals] p3 following that quoted above
+to be
+taken into account:
+
    
+
+
    
+-3- ... If pos or neg is empty, the sign component is
+optional, and if no sign is detected, the result is given the sign that
+corresponds to the source of the empty string. Otherwise, the character
+in the indicated position must match the first character of pos
+or neg, and the result is given the corresponding sign. If the
+first character of pos is equal to the first character of
+neg, or if both strings are empty, the result is given a
+positive sign.
+
    
+
+
    
+So a negative_sign of "" means "there is no way to write a
+negative sign" only when positive_sign is also "".  However
+when negative_sign is "" and postive_sign.size() >
+0, then one writes a negative value by not writing the
+postive_sign in the position indicated by
+money_base::sign.
+For example:
+
    
+
+
    pattern = {symbol, sign, value, none}
+positive_sign = "+"
+negative_sign = ""
+$123   // a negative value, using optional sign
+$+123  // a positive value
+$-123  // a parse error
+
    
+
+
    
+And:
+
    
+
+
    pattern = {symbol, sign, value, none}
+positive_sign = ""
+negative_sign = ""
+$123   // a positive value, no sign possible
+$+123  // a parse error
+$-123  // a parse error
+
    
+
+
+
    
+And (regarding 669):
+
    
+
+
    pattern = {symbol, sign, value, none}
+positive_sign = "-"
+negative_sign = "-"
+$123   // a parse error, sign is mandatory
+$+123  // a parse error
+$-123  // a positive value
+
    
+
+
+
    
+The text seems both unambiguous and clear to me.  I recommend NAD for
+both this issue and 669.  However I would have no
+objection to adding examples such as those above.
+
    
+
    
+
+
    [
+Batavia (2009-05):
+]
    
+
+
    
+
    
+This discussion applies equally to issue 669 (q.v.).
+Howard has added examples above,
+and recommends either NAD or a resolution that adds his (or similar) examples
+to the Working Paper.
+
    
+
    
+Alan would like to rewrite paragraph 3.
+
    
+
    
+We recommend moving to NAD.
+Anyone who feels strongly about adding the examples
+is invited to submit corresponding wording.
+We further recommend issue 669 be handled identically.
+
    
+
    
+
+
    [
+2009-07-14 Alan reopens with improved wording.
+]
    
+
+
+
    [
+2009-07 Frankfurt
+]
    
+
+
+
    
+No consensus for closing as NAD.  Leave in Review.
+
    
+
+
    [
+2009-10 Santa Cruz:
+]
    
+
+
+
    
+NAD.  Agreed that the original assessment as NAD was correct.
+
    
+
+
+
+
    Proposed resolution:
    
+
    
+Change 22.4.6.1.2 [locale.money.get.virtuals] p3:
+
    
+
+
    
+-3- If the first character (if any) in the string pos returned by
+mp.positive_sign() or the string neg returned by
+mp.negative_sign() is recognized in the position indicated by
+sign in the format pattern, it is consumed and any remaining characters
+in the string are required after all the other format components.
+[Example: If showbase is off, then for a neg
+value of "()" and a currency symbol of "L", in "(100 L)" the "L" is
+consumed; but if neg is "-", the "L" in "-100 L" is not
+consumed. -- end example] If pos or neg is
+empty, the sign component is optional, and if no sign is detected, the
+result is given the sign that corresponds to the source of the empty
+string. Otherwise, the character in the indicated position must match
+the first character of pos or neg, and the result is
+given the corresponding sign. If the first character of pos is
+equal to the first character of neg, or if both strings are
+empty, the result is given a positive sign.
+
+The sign pattern strings pos and neg are returned by
+mp.positive_sign() and mp.negative_sign() respectively. A sign pattern
+is matched if its first character is recognized in s in the position
+indicated by sign in the format pattern, or if the pattern is empty and
+there is no sign recognized in s. A match is required to occur. If both
+patterns are matched, the result is given a positive sign, otherwise the
+result is given the sign corresponding to the matched pattern. 
+If the pattern contains more than one character, the characters after the first 
+must be matched in s after all other format components. 
+If any sign
+characters are matched, s is consumed up to and including those characters.
+[Example: If showbase is off, then for a neg
+value of "()" and a currency symbol of "L", in
+"(100 L)" the entire string is consumed; but for a neg
+value of "-", in "-100 L", the string is consumed
+through the second "0" (the space and "L" are not consumed). — end
+example] 
+
    
+
+
+
+
+
 
    
 
    669. Equivalent postive and negative signs in money_get
    
 
    Section: 22.4.6.1.2 [locale.money.get.virtuals] Status: NAD
  Submitter: Thomas Plum Opened: 2007-04-16  Last modified: 2009-07-13
    
-
    View other active issues in [locale.money.get.virtuals].
    
 
    View all other issues in [locale.money.get.virtuals].
    
 
    View all issues with NAD status.
    
 
    Discussion:
    
@@ -14879,7 +16815,7 @@ Bill to provide proposed wording and interpretation of existing wording.
 
 
 
    [
-2009-05-17 See Howard's comments in related issue 668.
+2009-05-17 See Howard's comments in related issue 668.
 ]
    
 
 
@@ -14889,7 +16825,7 @@ Batavia (2009-05):
 
 
    
 
    
-This discussion applies equally to issue 668 (q.v.).
+This discussion applies equally to issue 668 (q.v.).
 Howard has added examples there,
 and recommends either NAD or a resolution that adds his (or similar) examples
 to the Working Paper.
@@ -14898,7 +16834,7 @@ to the Working Paper.
 We recommend moving to NAD.
 Anyone who feels strongly about adding the examples
 is invited to submit corresponding wording.
-We further recommend issue 668 be handled identically.
+We further recommend issue 668 be handled identically.
 
    
 
    
 
@@ -15106,13 +17042,13 @@ Bellevue:  Proposed wording now in WP.
 
 
    
 
    686. Unique_ptr and shared_ptr fail to specify non-convertibility to int for unspecified-bool-type
    
-
    Section: 20.8.9.2.4 [unique.ptr.single.observers], 20.8.10.2.5 [util.smartptr.shared.obs] Status: NAD
+
    Section: 20.8.14.2.4 [unique.ptr.single.observers], 20.8.15.2.5 [util.smartptr.shared.obs] Status: NAD
  Submitter: Beman Dawes Opened: 2007-06-14  Last modified: 2008-02-27
    
 
    View all issues with NAD status.
    
 
    Discussion:
    
 
    
 The standard library uses the operator unspecified-bool-type() const idiom in
-five places. In three of those places (20.7.16.2.3 [func.wrap.func.cap], function capacity 
+five places. In three of those places (20.7.15.2.3 [func.wrap.func.cap], function capacity 
 for example) the returned value is constrained to disallow
 unintended conversions to int. The standardese is
 
    
@@ -15140,8 +17076,8 @@ makes it irrelevant.
 
    
 To the Returns paragraph for operator unspecified-bool-type()
 const
-of 20.8.9.2.4 [unique.ptr.single.observers] paragraph 11 and
-20.8.10.2.5 [util.smartptr.shared.obs] paragraph 16, add the sentence:
+of 20.8.14.2.4 [unique.ptr.single.observers] paragraph 11 and
+20.8.15.2.5 [util.smartptr.shared.obs] paragraph 16, add the sentence:
 
    
 
    
 The return type shall not be convertible to int.
@@ -15605,6 +17541,138 @@ different, a string abstraction in its own right.
 
 
 
+
    
+
    719. std::is_literal type traits should be provided
    
+
    Section: 20.6 [meta] Status: NAD Editorial
+ Submitter: Daniel Krügler Opened: 2007-08-25  Last modified: 2009-10-26
    
+
    View all other issues in [meta].
    
+
    View all issues with NAD Editorial status.
    
+
    Duplicate of: 750
    
+
    Discussion:
    
+
    
+Since the inclusion of constexpr in the standard draft N2369 we have
+a new type category "literal", which is defined in 3.9 [basic.types]/p.11:
+
    
+
+
    
+
    
+-11- A type is a literal type if it is:
+
    
+
      
+
    • a scalar type; or
      • 
+
    • a class type (clause 9) with
      
+
        
+
      • a trivial copy constructor,
        • 
+
      • a trivial destructor,
        • 
+
      • at least one constexpr constructor other than the copy constructor,
        • 
+
      • no virtual base classes, and
        • 
+
      • all non-static data members and base classes of literal types; or
        • 
+
      
+
      • 
+
    • an array of literal type.
      • 
+
    
+
    
+
+
    
+I strongly suggest that the standard provides a type traits for
+literal types in 20.6.4.3 [meta.unary.prop] for several reasons:
+
    
+
+
      
+
    1. To keep the traits in sync with existing types.
      2. 
+
    2. I see many reasons for programmers to use this trait in template
+   code to provide optimized template definitions for these types,
+   see below.
      3. 
+
    3. A user-provided definition of this trait is practically impossible
+to write portably.
      4. 
+
    
+
+
    
+The special problem of reason (c) is that I don't see currently a
+way to portably test the condition for literal class types:
+
    
+
+
    
+
      
+
    • at least one constexpr constructor other than the copy constructor,
      • 
+
    
+
    
+
+
+
+
    [
+Alisdair is considering preparing a paper listing a number of missing
+type traits, and feels that it might be useful to handle them all
+together rather than piecemeal. This would affect issue 719 and 750.
+These two issues should move to OPEN pending AM paper on type traits.
+]
    
+
+
+
    [
+2009-07 Frankfurt:
+]
    
+
+
+
    
+Beman, Daniel, and Alisdair will work on a paper proposing new type traits.
+
    
+
+
    [
+Addressed in N2947.
+]
    
+
+
+
    [
+2009-10 Santa Cruz:
+]
    
+
+
+
    
+NAD Editorial.  Solved by
+N2984.
+
    
+
+
+
+
    Proposed resolution:
    
+
    
+In 20.6.2 [meta.type.synop] in the group "type properties",
+just below the line
+
    
+
+
    template <class T> struct is_pod;
+
    
+
+
    
+add a new one:
+
    
+
+
    template <class T> struct is_literal;
+
    
+
+
    
+In 20.6.4.3 [meta.unary.prop], table Type Property Predicates, just
+below the line for the is_pod property add a new line:
+
    
+
+
+
+
+
+
+
+
+
+
+
    TemplateConditionPreconditions
    template <class T> struct is_literal;T is a literal type (3.9)T shall be a complete type, an
+array of unknown bound, or
+(possibly cv-qualified) void.
    
+
+
+
+
+
+
 
    
 
    721. wstring_convert inconsistensies
    
 
    Section: 22.3.3.2.2 [conversions.string] Status: NAD
@@ -15674,6 +17742,7 @@ Move to NAD.
 
    725. Optional sequence container requirements column label
    
 
    Section: 23.2.3 [sequence.reqmts] Status: NAD Editorial
  Submitter: David Abrahams Opened: 2007-09-16  Last modified: 2008-09-22
    
+
    View other active issues in [sequence.reqmts].
    
 
    View all other issues in [sequence.reqmts].
    
 
    View all issues with NAD Editorial status.
    
 
    Discussion:
    
@@ -16458,7 +18527,7 @@ for the proposed resolution.
 
 
    
 
    741. Const-incorrect get_deleter function for shared_ptr
    
-
    Section: 20.8.10.2.11 [util.smartptr.getdeleter] Status: NAD
+
    Section: 20.8.15.2.11 [util.smartptr.getdeleter] Status: NAD
  Submitter: Daniel Krügler Opened: 2007-09-27  Last modified: 2008-02-27
    
 
    View all other issues in [util.smartptr.getdeleter].
    
 
    View all issues with NAD status.
    
@@ -16469,7 +18538,7 @@ The following issue was raised by Alf P. Steinbach in c.l.c++.mod:
 
 
    
 According to the recent draft N2369, both the header memory synopsis
-of 20.8 [memory] and 20.8.10.2.11 [util.smartptr.getdeleter] declare:
+of 20.8 [memory] and 20.8.15.2.11 [util.smartptr.getdeleter] declare:
 
    
 
 
    template<class D, class T> D* get_deleter(shared_ptr<T> const& p);
@@ -16484,7 +18553,7 @@ the mutability of the owner (as seen for the both overloads of
 unique_ptr::get_deleter).
 Even the next similar counter-part of get_deleter - the two
 overloads of function::target in the class template function
-synopsis 20.7.16.2 [func.wrap.func] or in 20.7.16.2.5 [func.wrap.func.targ] - do
+synopsis 20.7.15.2 [func.wrap.func] or in 20.7.15.2.5 [func.wrap.func.targ] - do
 properly mirror the const-state of the owner.
 
    
 
@@ -16492,7 +18561,7 @@ properly mirror the const-state of the owner.
 
 
    
 Replace the declarations of get_deleter in the header <memory>
-synopsis of 20.8 [memory] and in 20.8.10.2.11 [util.smartptr.getdeleter] by one of the
+synopsis of 20.8 [memory] and in 20.8.15.2.11 [util.smartptr.getdeleter] by one of the
 following alternatives (A) or (B):
 
    
 
@@ -16733,10 +18802,10 @@ Core has clarified that the definition abstract is adequate. Issue withdrawn by
 
    750. The current definition for is_convertible requires that the type be
 implicitly convertible, so explicit constructors are ignored.
    
 
    Section: 20.6.5 [meta.rel] Status: Dup
- Submitter: Alisdair Meredith Opened: 2007-10-10  Last modified: 2009-07-16
    
+ Submitter: Alisdair Meredith Opened: 2007-10-10  Last modified: 2009-09-13
    
 
    View all other issues in [meta.rel].
    
 
    View all issues with Dup status.
    
-
    Duplicate of: 719
    
+
    Duplicate of: 719
    
 
    Discussion:
    
 
    
 With the pending arrival of explicit conversion functions though, I'm
@@ -16761,9 +18830,15 @@ These two issues should move to OPEN pending AM paper on type traits.
 
 
 
    
-Duplicate of 719 (for our purposes).
+Duplicate of 719 (for our purposes).
 
    
 
+
    [
+Addressed in N2947.
+]
    
+
+
+
 
 
    Proposed resolution:
    
 
@@ -16856,7 +18931,7 @@ NAD.  Insufficient motivation to make any changes.
 
 
    
 
    754. Ambiguous return clause for std::uninitialized_copy
    
-
    Section: 20.8.8.2 [uninitialized.copy] Status: NAD Editorial
+
    Section: 20.8.13.2 [uninitialized.copy] Status: NAD Editorial
  Submitter: Daniel Krügler Opened: 2007-10-15  Last modified: 2008-07-02
    
 
    View all other issues in [uninitialized.copy].
    
 
    View all issues with NAD Editorial status.
    
@@ -16886,7 +18961,7 @@ NAD.  Insufficient motivation to make any changes.
 
 
    
 similarily for N2369, and its corresponding section
-20.8.8.2 [uninitialized.copy].
+20.8.13.2 [uninitialized.copy].
 
    
 
 
    
@@ -16934,7 +19009,7 @@ for std::copy.
 
 
    Proposed resolution:
    
 
    
-Change the wording of the return clause to say (20.8.8.2 [uninitialized.copy]):
+Change the wording of the return clause to say (20.8.13.2 [uninitialized.copy]):
 
    
 
 
    
@@ -16962,6 +19037,8 @@ occur.
 
    756. Container adaptors push
    
 
    Section: 23.3.5 [container.adaptors] Status: NAD Editorial
  Submitter: Paolo Carlini Opened: 2007-10-31  Last modified: 2008-06-18
    
+
    View other active issues in [container.adaptors].
    
+
    View all other issues in [container.adaptors].
    
 
    View all issues with NAD Editorial status.
    
 
    Discussion:
    
 
    
@@ -17058,7 +19135,6 @@ Addressed by
 
    757. Typo in the synopsis of vector
    
 
    Section: 23.3.6 [vector] Status: NAD Editorial
  Submitter: Paolo Carlini Opened: 2007-11-04  Last modified: 2008-07-02
    
-
    View other active issues in [vector].
    
 
    View all other issues in [vector].
    
 
    View all issues with NAD Editorial status.
    
 
    Discussion:
    
@@ -17186,6 +19262,7 @@ elements of the container. No diagnostic required.
 
    763. Renaming emplace() overloads
    
 
    Section: 23.2.4 [associative.reqmts] Status: NAD
  Submitter: Sylvain Pion Opened: 2007-12-04  Last modified: 2008-03-12
    
+
    View other active issues in [associative.reqmts].
    
 
    View all other issues in [associative.reqmts].
    
 
    View all issues with NAD status.
    
 
    Discussion:
    
@@ -19123,7 +21200,7 @@ Addressed by
 
 
    
 
    812. unsolicited multithreading considered harmful?
    
-
    Section: 25.5.1 [alg.sort] Status: NAD Editorial
+
    Section: 25.4.1 [alg.sort] Status: NAD Editorial
  Submitter: Paul McKenney Opened: 2008-02-27  Last modified: 2008-09-17
    
 
    View all issues with NAD Editorial status.
    
 
    Discussion:
    
@@ -19165,24 +21242,158 @@ This is already covered by 17.6.5.6/20 in N2723.
 
 
 
    
-
    825. Missing rvalues reference stream insert/extract operators?
    
-
    Section: 19.5.2.2 [syserr.errcode.overview], 20.8.10.2.8
-[util.smartptr.shared.io], 22.4.8 [facets.examples], 20.3.6.3
-[bitset.operators], 26.4.6 [complex.ops], 27.6 [stream.buffers], 28.9
-[re.submatch] Status: NAD Editorial
- Submitter: Alisdair Meredith Opened: 2008-04-10  Last modified: 2009-07-13
    
+
    823. identity<void> seems broken
    
+
    Section: 20.3.3 [forward] Status: NAD Editorial
+ Submitter: Walter Brown Opened: 2008-04-09  Last modified: 2009-10-23
    
+
    View all other issues in [forward].
    
 
    View all issues with NAD Editorial status.
    
 
    Discussion:
    
+
    
+N2588 seems to have added an operator() member function to the
+identity<> helper in 20.3.3 [forward].  I believe this change makes it no
+longer possible to instantiate identity<void>, as it would require
+forming a reference-to-void type as this operator()'s parameter type.
+
    
+
+
    
+Suggested resolution:  Specialize identity<void> so as not to require
+the member function's presence.
+
    
+
+
    [
+Sophia Antipolis:
+]
    
+
+
+
    
+
    
+Jens: suggests to add a requires clause to avoid specializing on void.
+
    
+
    
+Alisdair: also consider cv-qualified void.
+
    
+
    
+Alberto provided proposed wording.
+
    
+
    
+
+
    [
+2009-07-30 Daniel reopens:
+]
    
+
+
+
    
+
    
+This issue became closed, because the ReferentType requirement
+fixed the problem - this is no longer the case. In retrospective it seems
+to be that the root of current issues around std::identity (823, 700,
+939)
+is that it was standardized as something very different (an unconditional
+type mapper) than traditional usage indicated (a function object that should
+derive from std::unary_function), as the SGI definition does. This issue could
+be solved, if std::identity is removed (one proposal of 939), but until this
+has been decided, this issue should remain open. An alternative for
+removing it, would be, to do the following:
+
    
+
+
      
+
    1. 
+
      
+Let identity stay as a real function object, which would
+now properly
+derive from unary_function:
+
      
+
+
      template <class T> struct identity : unary_function<T, T> {
+  const T& operator()(const T&) const;
+};
+
      
+
      2. 
+
+
    2. 
+
      
+Invent (if needed) a generic type wrapper (corresponding to concept
+IdentityOf),
+e.g. identity_of, and move it's prototype description back to 20.3.3 [forward]:
+
      
+
+
      template <class T> struct identity_of {
+  typedef T type;
+};
+
      
+
+
      
+and adapt the std::forward signature to use identity_of
+instead of identity.
+
      
+
      3. 
+
    
+
    
+
+
    [
+2009-10 Santa Cruz:
+]
    
+
+
+
    
+Mark as NAD Editorial, fixed by 939.
+
    
+
+
+
+
    Proposed resolution:
    
+
    
+Change definition of identity in 20.3.3 [forward], paragraph 2, to:
+
    
+
+
    template <class T>  struct identity {
+    typedef T type;
+
+    requires ReferentType<T>
+      const T& operator()(const T& x) const;
+  };
+
    
+
    ...
    
+
      requires ReferentType<T>
+    const T& operator()(const T& x) const;
+
    
+
+
+
    Rationale:
    
+
    
+The point here is to able to write T& given T and ReferentType is
+precisely the concept that guarantees so, according to N2677
+(Foundational concepts). Because of this, it seems preferable than an
+explicit check for cv void using SameType/remove_cv as it was suggested
+in Sophia. In particular, Daniel remarked that there may be types other
+than cv void which aren't referent types (int[], perhaps?).
+
    
+
+
+
+
+
+
    
+
    825. Missing rvalues reference stream insert/extract operators?
    
+
    Section: 19.5.2.1 [syserr.errcode.overview], 20.8.15.2.8
+[util.smartptr.shared.io], 22.4.8 [facets.examples], 20.3.7.3
+[bitset.operators], 26.4.6 [complex.ops], 27.6 [stream.buffers], 28.9
+[re.submatch] Status: NAD Editorial
+ Submitter: Alisdair Meredith Opened: 2008-04-10  Last modified: 2009-10-26
    
+
    View all issues with NAD Editorial status.
    
+
    Discussion:
    
+
    Addresses UK 220
    
+
 
    
 Should the following use rvalues references to stream in insert/extract
 operators?
 
    
 
 
      
-
    • 19.5.2.2 [syserr.errcode.overview]
      • 
-
    • 20.8.10.2.8 [util.smartptr.shared.io]
      • 
+
    • 19.5.2.1 [syserr.errcode.overview]
      • 
+
    • 20.8.15.2.8 [util.smartptr.shared.io]
      • 
 
    • 22.4.8 [facets.examples]
      • 
-
    • 20.3.6.3 [bitset.operators]
      • 
+
    • 20.3.7.3 [bitset.operators]
      • 
 
    • 26.4.6 [complex.ops]
      • 
 
    • Doubled signatures in 27.6 [stream.buffers] for character inserters
 (ref 27.7.2.6.4 [ostream.inserters.character])
@@ -19298,6 +21509,231 @@ This is not a part of C99. LWG suggests submitting a paper may be appropriate.
 
 
 
+
      
+
      827. constexpr shared_ptr::shared_ptr()?
      
+
      Section: 20.8.15.2.1 [util.smartptr.shared.const] Status: NAD Editorial
+ Submitter: Peter Dimov Opened: 2008-04-11  Last modified: 2009-10-26
      
+
      View all other issues in [util.smartptr.shared.const].
      
+
      View all issues with NAD Editorial status.
      
+
      Discussion:
      
+
      
+Would anyone object to making the default constructor of shared_ptr (and
+weak_ptr and enable_shared_from_this) constexpr? This would enable
+static initialization for shared_ptr variables, eliminating another
+unfair advantage of raw pointers.
+
      
+
+
      [
+San Francisco:
+]
      
+
+
+
      
+
      
+It's not clear to us that you can initialize a pointer with the literal
+0 in a constant expression. We need to ask CWG to make sure this works.
+Bjarne has been appointed to do this.
+
      
+
      
+Core got back to us and assured as that nullptr would do the job
+nicely here.
+
      
+
      
+
+
      [
+2009-05-01 Alisdair adds:
+]
      
+
+
+
      
+
      
+I don't believe that constexpr will buy anything in this case.
+shared_ptr/weak_ptr/enable_shared_from_this cannot be literal types as they
+have a non-trivial copy constructor.  As they do not produce literal types,
+then the constexpr default constructor will not guarantee constant
+initialization, and so not buy the hoped for optimization.
+
      
+
      
+I recommend referring this back to Core to see if we can get static
+initialization for types with constexpr constructors, even if they are not
+literal types.  Otherwise this should be closed as NAD.
+
      
+
      
+
+
      [
+2009-05-26 Daniel adds:
+]
      
+
+
+
      
+If Alisdair's 2009-05-01 comment is correct, wouldn't that also make
+constexpr mutex() useless, because this class has a non-trivial
+destructor? (828)
+
      
+
+
      [
+2009-07-21 Alisdair adds:
+]
      
+
+
+
      
+
      
+The feedback from core is that this and similar uses of constexpr
+constructors to force static initialization should be supported.  If
+there are any problems with this in the working draught, we should file
+core issues.
+
      
+
+
      
+Recommend we declare the default constructor constexpr as the issue suggests
+(proposed wording added).
+
      
+
      
+
+
      [
+2009-10 Santa Cruz:
+]
      
+
+
+
      
+NAD Editorial.  Solved by
+N2994.
+
      
+
+
+
      Proposed resolution:
      
+
      
+Change 20.8.15.2 [util.smartptr.shared] and 20.8.15.2.1 [util.smartptr.shared.const]:
+
      
+
+
      consexpr shared_ptr();
+
      
+
+
      
+Change 20.8.15.3 [util.smartptr.weak] and 20.8.15.3.1 [util.smartptr.weak.const]:
+
      
+
+
      consexpr weak_ptr();
+
      
+
+
      
+Change 20.8.15.4 [util.smartptr.enab] (2 places):
+
      
+
+
      consexpr enable_shared_from_this();
+
      
+
+
+
+
+
+
+
      
+
      828. Static initialization for std::mutex?
      
+
      Section: 30.4.1.1 [thread.mutex.class] Status: NAD Editorial
+ Submitter: Peter Dimov Opened: 2008-04-18  Last modified: 2009-10-26
      
+
      View all other issues in [thread.mutex.class].
      
+
      View all issues with NAD Editorial status.
      
+
      Discussion:
      
+
      
+[Note: I'm assuming here that 3.6.2 [basic.start.init]/1 will be fixed.]
+
      
+
      
+Currently std::mutex doesn't support static initialization. This is a
+regression with respect to pthread_mutex_t, which does. I believe that
+we should strive to eliminate such regressions in expressive power where
+possible, both to ease migration and to not provide incentives to (or
+force) people to forego the C++ primitives in favor of pthreads.
+
      
+
+
      [
+Sophia Antipolis:
+]
      
+
+
+
      
+
      
+We believe this is implementable on POSIX, because the initializer-list
+feature and the constexpr feature make this work. Double-check core
+language about static initialization for this case. Ask core for a core
+issue about order of destruction of statically-initialized objects wrt.
+dynamically-initialized objects (should come afterwards). Check
+non-POSIX systems for implementability.
+
      
+
      
+If ubiquitous implementability cannot be assured, plan B is to introduce
+another constructor, make this constexpr, which is
+conditionally-supported. To avoid ambiguities, this new constructor needs
+to have an additional parameter.
+
      
+
      
+
+
      [
+Post Summit:
+]
      
+
+
+
      
+
      
+Jens: constant initialization seems to be ok core-language wise
+
      
+
      
+Consensus: Defer to threading experts, in particular a Microsoft platform expert.
+
      
+
      
+Lawrence to send e-mail to Herb Sutter, Jonathan Caves, Anthony Wiliams,
+Paul McKenney, Martin Tasker, Hans Boehm, Bill Plauger, Pete Becker,
+Peter Dimov to alert them of this issue.
+
      
+
      
+Lawrence: What about header file shared with C? The initialization
+syntax is different in C and C++.
+
      
+
      
+Recommend Keep in Review
+
      
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+Keep in Review status pending feedback from members of the Concurrency subgroup.
+
      
+
+
      [
+See related comments from Alisdiar and Daniel in 827.
+]
      
+
+
+
      [
+2009-10 Santa Cruz:
+]
      
+
+
+
      
+NAD Editorial.  Solved by
+N2994.
+
      
+
+
+
+
      Proposed resolution:
      
+
      
+Change 30.4.1.1 [thread.mutex.class]:
+
      
+
+
      class mutex {
+public:
+  constexpr mutex();
+  ...
+
      
+
+
+
+
+
 
      
 
      830. Incomplete list of char_traits specializations
      
 
      Section: 21.2 [char.traits] Status: NAD Editorial
@@ -19604,7 +22040,7 @@ Thus implementations are given latitude in determining correspondence.
 
    
 
 
    
-Change 19.5.2.2 [syserr.errcode.overview] Class error_code overview as indicated:
+Change 19.5.2.1 [syserr.errcode.overview] Class error_code overview as indicated:
 
    
 
 
    class error_code {
@@ -19622,7 +22058,7 @@ private:
 
    
 
 
    
-Change 19.5.2.3 [syserr.errcode.constructors] Class error_code constructors as indicated:
+Change 19.5.2.2 [syserr.errcode.constructors] Class error_code constructors as indicated:
 
    
 
 
    
@@ -19640,7 +22076,7 @@ Change 19.5.2.3 [syserr.errcode.constructors] Class error_code construc
 
    
 
 
    
-Change 19.5.2.4 [syserr.errcode.modifiers] Class error_code modifiers  as indicated:
+Change 19.5.2.3 [syserr.errcode.modifiers] Class error_code modifiers  as indicated:
 
    
 
 
    
@@ -19655,7 +22091,7 @@ Change 19.5.2.4 [syserr.errcode.modifiers] Class error_code modifiers
 
    
 
 
    
-Change 19.5.2.5 [syserr.errcode.observers] Class error_code observers  as indicated:
+Change 19.5.2.4 [syserr.errcode.observers] Class error_code observers  as indicated:
 
    
 
 
    
@@ -19671,7 +22107,7 @@ Change 19.5.2.5 [syserr.errcode.observers] Class error_code observers
 
    
 
 
    
-Change 19.5.3.2 [syserr.errcondition.overview] Class error_condition overview   as indicated:
+Change 19.5.3.1 [syserr.errcondition.overview] Class error_condition overview   as indicated:
 
    
 
 
    
@@ -19691,7 +22127,7 @@ private:
 
    
 
 
    
-Change 19.5.3.3 [syserr.errcondition.constructors] Class error_condition constructors as indicated:
+Change 19.5.3.2 [syserr.errcondition.constructors] Class error_condition constructors as indicated:
 
    
 
 
    
@@ -19709,7 +22145,7 @@ Change 19.5.3.3 [syserr.errcondition.constructors] Class error_condition
 
 
    
-Change 19.5.3.4 [syserr.errcondition.modifiers] Class error_condition modifiers as indicated:
+Change 19.5.3.3 [syserr.errcondition.modifiers] Class error_condition modifiers as indicated:
 
    
 
 
    
@@ -19724,7 +22160,7 @@ Change 19.5.3.4 [syserr.errcondition.modifiers] Class error_condition m
 
    
 
 
    
-Change 19.5.3.5 [syserr.errcondition.observers] Class error_condition observers as indicated:
+Change 19.5.3.4 [syserr.errcondition.observers] Class error_condition observers as indicated:
 
    
 
 
    
@@ -20029,7 +22465,7 @@ already there.
 
    
 
    839. Maps and sets missing splice operation
    
 
    Section: 23.4 [associative], 23.5 [unord] Status: NAD Future
- Submitter: Alan Talbot Opened: 2008-05-18  Last modified: 2009-07-16
    
+ Submitter: Alan Talbot Opened: 2008-05-18  Last modified: 2009-09-20
    
 
    View all other issues in [associative].
    
 
    View all issues with NAD Future status.
    
 
    Discussion:
    
@@ -20141,6 +22577,177 @@ that demonstrates that it works.
 NAD Future.
 
    
 
+
    [
+2009-09-19 Howard adds:
+]
    
+
+
+
    
+
    
+I'm not disagreeing with the NAD Future resolution.  But when the future gets
+here, here is a possibility worth exploring:
+
    
+
+
    
+
    
+Add to the "unique" associative containers:
+
    
+
+
    typedef details      node_ptr;
+
+node_ptr             remove(const_iterator p);
+pair<iterator, bool> insert(node_ptr&& nd);
+iterator             insert(const_iterator p, node_ptr&& nd);
+
    
+
+
    
+And add to the "multi" associative containers:
+
    
+
+
    typedef details node_ptr;
+
+node_ptr remove(const_iterator p);
+iterator insert(node_ptr&& nd);
+iterator insert(const_iterator p, node_ptr&& nd);
+
    
+
+
    
+Container::node_ptr is a smart pointer much like unique_ptr.
+It owns a node obtained from the container it was removed from.  It maintains a
+reference to the allocator in the container so that it can properly deallocate
+the node if asked to, even if the allocator is stateful.  This being said, the
+node_ptr can not outlive the container for this reason.
+
    
+
+
    
+The node_ptr offers "const-free" access to the node's
+value_type.
+
    
+
+
    
+With this interface, clients have a great deal of flexibility:
+
    
+
+
      
+
    • 
+A client can remove a node from one container, and insert it into another
+(without any heap allocation).  This is the splice functionality this issue
+asks for.
+
      • 
+
    • 
+A client can remove a node from a container, change its key or value, and insert
+it back into the same container, or another container, all without the cost of
+allocating a node.
+
      • 
+
    • 
+If the Compare function is nothrow (which is very common), then this functionality
+is nothrow unless modifying the value throws.  And if this does throw, it does
+so outside of the containers involved.
+
      • 
+
    • 
+If the Compare function does throw, the insert function will have the
+argument nd retain ownership of the node.
+
      • 
+
    • 
+The node_ptr should be independent of the Compare parameter
+so that a node can be transferred from set<T, C1, A>
+to set<T, C2, A> (for example).
+
      • 
+
    
+
+
    
+Here is how the customer might use this functionality:
+
    
+
+
      
+
    • 
+
      
+Splice a node from one container to another:
+
      
+
      m2.insert(m1.remove(i));
+
      
+
      • 
+
+
    • 
+
      
+Change the "key" in a std::map without the cost of node reallocation:
+
      
+
      auto p = m.remove(i);
+p->first = new_key;
+m.insert(std::move(p));
+
      
+
      • 
+
+
    • 
+
      
+Change the "value" in a std::set without the cost of node reallocation:
+
      
+
      auto p = s.remove(i);
+*p = new_value;
+s.insert(std::move(p));
+
      
+
      • 
+
+
    • 
+
      
+Move a move-only or heavy object out of an associative container (as opposed to
+the proposal in 1041):
+
      
+
      MoveOnly x = std::move(*s.remove(i));
+
      
+
        
+
      1. 
+remove(i) transfers ownership of the node from the set to a temporary
+node_ptr.
+
        2. 
+
      2. 
+The node_ptr is dereferenced, and that non-const reference is sent to
+move to cast it to an rvalue.
+
        3. 
+
      3. 
+The rvalue MoveOnly is move constructed into x from
+the node_ptr.
+
        4. 
+
      4. 
+~node_ptr() destructs the moved-from MoveOnly and deallocates
+the node.
+
        5. 
+
      
+
+
      
+Contrast this with the 1041 solution:
+
      
+
      MoveOnly x = std::move(s.extract(i).first);
+
      
+
+
      
+The former requires one move construction for x while the latter
+requires two (one into the pair and then one into x).  Either
+of these constructions can throw (say if there is only a copy constructor for
+x).  With the former, the point of throw is outside of the container
+s, after the element has been removed from the container.  With the latter,
+one throwing construction takes place prior to the removal of the element, and
+the second takes place after the element is removed.
+
      
+
+
      • 
+
    
+
+
    
+The "node insertion" API maintains the API associated with inserting value_types
+so the customer can use familiar techniques for getting an iterator to the 
+inserted node, or finding out whether it was inserted or not for the "unique"
+containers.
+
    
+
+
    
+Lightly prototyped.  No implementation problems.  Appears to work great
+for the client.
+
    
+
+
    
+
    
+
 
 
 
    Proposed resolution:
    
@@ -20151,7 +22758,7 @@ NAD Future.
 
 
    
 
    840. pair default template argument
    
-
    Section: 20.3.3 [pairs] Status: NAD
+
    Section: 20.3.4 [pairs] Status: NAD
  Submitter: Thorsten Ottosen Opened: 2008-05-23  Last modified: 2008-06-18
    
 
    View other active issues in [pairs].
    
 
    View all other issues in [pairs].
    
@@ -20175,7 +22782,7 @@ Change the synopsis in 20.3 [utility] to read:
 
    
 
 
    
-Change 20.3.3 [pairs] to read:
+Change 20.3.4 [pairs] to read:
 
    
 
 
    namespace std {
@@ -20438,7 +23045,6 @@ and macros are required.
 
    849. missing type traits to compute root class and derived class of types in a class hierachy
    
 
    Section: 20.6.7 [meta.trans.other] Status: NAD
  Submitter: Thorsten Ottosen Opened: 2008-06-05  Last modified: 2008-09-16
    
-
    View other active issues in [meta.trans.other].
    
 
    View all other issues in [meta.trans.other].
    
 
    View all issues with NAD status.
    
 
    Discussion:
    
@@ -20520,6 +23126,338 @@ as an accessible unambiguous direct base class. If no such type exists, the memb
 
 
 
+
    
+
    851. simplified array construction
    
+
    Section: 23.3.1 [array] Status: NAD Future
+ Submitter: Benjamin Kosnik Opened: 2008-06-05  Last modified: 2009-10-23
    
+
    View all other issues in [array].
    
+
    View all issues with NAD Future status.
    
+
    Discussion:
    
+
    
+This is an issue that came up on the libstdc++ list, where a
+discrepancy between "C" arrays and C++0x's std::array was pointed
+out.
+
    
+
+
    
+In "C," this array usage is possible:
+
    
+
+
    int ar[] = {1, 4, 6};
+
    
+
+
    
+But for C++, 
+
    
+
+
    std::array<int> a = { 1, 4, 6 }; // error
+
    
+
+
    
+Instead, the second parameter of the array template must be
+explicit, like so:
+
    
+
+
    std::array<int, 3> a = { 1, 4, 6 };
+
    
+
+
    
+Doug Gregor proposes the following solution, that assumes
+generalized initializer lists.
+
    
+
+
    template<typename T, typename... Args>
+inline array<T, sizeof...(Args)> 
+make_array(Args&&... args) 
+{ return { std::forward<Args>(args)... };  }
+
    
+
+
    
+Then, the way to build an array from a list of unknown size is:
+
    
+
+
    auto a = make_array<T>(1, 4, 6);
+
    
+
+
    [
+San Francisco:
+]
    
+
+
+
    
+
    
+Benjamin: Move to Ready?
+
    
+
    
+Bjarne: I'm not convinced this is useful enough to add, so I'd like us
+to have time to reflect on it.
+
    
+
    
+Alisdair: the constraints are wrong, they should be
+
    
+
    template<ValueType T, ValueType... Args>
+requires Convertible<Args, T>...
+array<T, sizeof...(Args)> make_array(Args&&... args);
+
    
+
    
+Alidair: this would be useful if we had a constexpr version.
+
    
+
    
+Bjarne: this is probably useful for arrays with a small number of
+elements, but it's not clearly useful otherwise.
+
    
+
    
+Consensus is to move to Open.
+
    
+
    
+
+
    [
+2009-06-07 Daniel adds:
+]
    
+
+
+
    
+
    
+I suggest a fix and a simplification of the current proposal: Recent
+prototyping by
+Howard showed, that a fix is required because narrowing conversion
+8.5.4 [dcl.init.list]/6 b.3
+would severely limit the possible distribution of argument types, e.g.
+the expression
+make_array<double>(1, 2.0) is ill-formed, because the narrowing
+happens inside the
+function body where no constant expressions exist anymore. Furthermore
+given e.g.
+
    
+
    int f();
+double g();
+
    
+
    
+we probably want to support
+
    
+
    make_array<double>(f(), g());
+
    
+
+
    
+as well. To make this feasible, the currently suggested expansion
+
    
+
+
    { std::forward<Args>(args)... }
+
    
+
+
    
+needs to be replaced by
+
    
+
+
    { static_cast<T>(std::forward<Args>(args))... }
+
    
+
+
    
+which is safe, because we already ensure convertibility via the
+element-wise Convertible<Args, T> requirement. Some other fixes are
+necessary: The ValueType requirement for the function parameters
+is invalid, because all lvalue arguments will deduce to an lvalue-reference,
+thereby no longer satisfying this requirement.
+
    
+
+
    
+The suggested simplification is to provide a default-computed effective
+type for the result array based on common_type and decay, in
+unconstrained form:
+
    
+
+
    template<typename... Args>
+array<typename decay<typename common_type<Args...>::type>::type,
+sizeof...(Args)>
+make_array(Args&&... args);
+
    
+
+
    
+The approach used below is similar to that of make_pair and make_tuple
+using a symbol C to represent the decayed common type [Note: Special
+handling of reference_wrapper types is intentionally not provided, because
+our target has so satisfy ValueType, thus under the revised proposal only
+an all-reference_wrapper-arguments would be well-formed and an array of
+reference_wrapper will be constructed]. I do currently not suggest to
+add new concepts reflecting decay and common_type, but an implementor will
+need something like this to succeed. Note that we use a similar fuzziness for
+make_pair and make_tuple currently. This fuzziness is not related to
+the currently
+missing Constructible<Vi, Ti&&> requirement for those functions. The following
+proposal fixes that miss for make_array. If the corresponding C type
+deduction is
+explicitly wanted for standardization, here the implementation
+
    
+
+
    auto concept DC<typename... T> {
+  typename type = typename decay<typename common_type<T...>::type>::type;
+}
+
    
+
+
    
+where C is identical to DC<Args...>::type in the proposed resolution below.
+
    
+
    
+I intentionally added no further type relation between type and the concept
+template parameters, but instead added this requirement below to make
+the specification as transparent as possible. As written this concept is
+satisfied, if the corresponding associated type exists.
+
    
+
+
    Suggested Resolution:
    
+
+
      
+
    1. 
+
      
+Add to the array synopsis in 23.3 [sequences]:
+
      
+
      
+template<ReferentType... Args>
+requires ValueType<C> && IdentityOf<Args> && Constructible<C, Args&&>...
+array<C, sizeof...(Args)>
+make_array(Args&&... args);
+
+
      
+
      2. 
+
+
    2. 
+
      
+Append after 23.3.1.7 [array.tuple] Tuple interface to class template array
+the following new section:
+
      
+
      
+
      
+23.4.1.7 Array creation functions [array.creation]
+
      
+
+
      
+template<ReferentType... Args>
+requires ValueType<C> && IdentityOf<Args> && Constructible<C, Args&&>...
+array<C, sizeof...(Args)>
+make_array(Args&&... args);
+
      
+
+
      
+
      
+Let C be decay<common_type<Args...>::type>::type.
+
      
+
      
+Returns: an array<C, sizeof...(Args)> initialized with
+{ static_cast<C>(std::forward<Args>(args))... }.
+
      
+
      
+
      
+
+
      3. 
+
+
    
+
+
    
+
+
    [
+2009-07 Frankfurt:
+]
    
+
+
+
    
+
    
+The proposed resolution uses concepts.
+
    
+
    
+Daniel to rewrite the proposed resolution.
+
    
+
    
+Leave Open.
+
    
+
    
+
+
    [
+2009-07-25 Daniel provides rewritten proposed resolution.
+]
    
+
+
+
    [
+2009-10 Santa Cruz:
+]
    
+
+
+
    
+Argument for NAD future: everything about this could be added on. This
+does not require changes to the existing text.
+
    
+
+
+
+
    Proposed resolution:
    
+
+
      
+
    1. 
+
      
+Add to the array synopsis in 23.3 [sequences]:
+
      
+
+
      template<class... Args>
+  array<CT, sizeof...(Args)>
+  make_array(Args&&... args);
+
      
+
      2. 
+
+
    2. 
+
      
+Append after 23.3.1.7 [array.tuple] "Tuple interface to class template array" the
+following new section:
+
      
+
+
      
+
      
+XX.X.X.X Array creation functions [array.creation]
+
      
+
+
      
+template<class... Args>
+array<CT, sizeof...(Args)>
+make_array(Args&&... args)
+
      
+
+
      
+
      
+Let CT be decay<common_type<Args...>::type>::type.
+
      
+
      
+Returns: An array<CT, sizeof...(Args)> initialized with {
+static_cast<CT>(std::forward<Args>(args))... }.
+
      
+
+
      
+[Example:
+
      
+
      
+int i = 0; int& ri = i;
+make_array(42u, i, 2.78, ri);
+
      
+
      
+returns an array of type
+
      
+
      
+array<double, 4>
+
      
+
+
      
+—end example]
+
      
+
      
+
      
+
      3. 
+
+
    
+
+
+
+
+
+
+
+
 
    
 
    855. capacity() and reserve() for deque?
    
 
    Section: 23.3.2.2 [deque.capacity] Status: NAD
@@ -20692,13 +23630,13 @@ Complication outweighs the benefit.
 
 
    
 
    862. Impossible complexity for 'includes'
    
-
    Section: 25.5.5.1 [includes] Status: NAD Editorial
+
    Section: 25.4.5.1 [includes] Status: NAD Editorial
  Submitter: Alisdair Meredith Opened: 2008-07-02  Last modified: 2009-07-13
    
 
    View all other issues in [includes].
    
 
    View all issues with NAD Editorial status.
    
 
    Discussion:
    
 
    
-In 25.5.5.1 [includes] the complexity is "at most -1 comparisons" if passed
+In 25.4.5.1 [includes] the complexity is "at most -1 comparisons" if passed
 two empty ranges.  I don't know how to perform a negative number of
 comparisions!
 
    
@@ -20722,7 +23660,7 @@ This same issue also applies to:
 
 
    
 Suggest NAD. The complexity of empty ranges is -1 in other places in the
-standard. See 25.5.4 [alg.merge] merge and
+standard. See 25.4.4 [alg.merge] merge and
 inplace_merge, and forward_list merge, for example.
 The time and effort to find and fix all places in the standard where
 empty range[s] result in negative complexity isn't worth the very
@@ -20821,7 +23759,6 @@ Move to NAD.
 
    864. Defect in atomic wording
    
 
    Section: 29.6 [atomics.types.operations] Status: NAD Editorial
  Submitter: Anthony Williams Opened: 2008-07-10  Last modified: 2008-09-17
    
-
    View other active issues in [atomics.types.operations].
    
 
    View all other issues in [atomics.types.operations].
    
 
    View all issues with NAD Editorial status.
    
 
    Discussion:
    
@@ -21041,7 +23978,7 @@ Post Summit Daniel adds:
 
 
    
 The proposed resolution needs to be "conceptualized". Currently we have
-in 14.10.4 [concept.support] only concept IntegralType
+in  [concept.support] only concept IntegralType
 for all "integral types", thus indeed the current Container
 concept and Iterator concepts are sufficiently satisfied with "integral
 types". If the changes are applied, we might ask core for concept
@@ -21085,7 +24022,7 @@ concepts.
       X::difference_type cannot be char or
       wchar_t, but could be one of the signed or unsigned integer
       types as appropriate.
-      X [allocator.requirements] table 40...
+      20.2.2 [allocator.requirements] table 40...
     
    
     
    
       Table 40: Allocator requirements
@@ -21319,7 +24256,7 @@ concepts.
     
    
 
     
    
-      24.2 [iterator.concepts] paragraph 1...
+      X [iterator.concepts] paragraph 1...
     
    
     
    
       Iterators are a generalization of pointers that allow a C++ program to
@@ -22051,9 +24988,179 @@ specification with a "Throws: Nothing." clause.
 
 
 
+
    
+
    879. Atomic load const qualification
    
+
    Section: 29 [atomics] Status: NAD Editorial
+ Submitter: Alexander Chemeris Opened: 2008-08-24  Last modified: 2009-10-26
    
+
    View all other issues in [atomics].
    
+
    View all issues with NAD Editorial status.
    
+
    Discussion:
    
+
    
+The atomic_address type and atomic<T*> specialization provide atomic
+updates to pointers.  However, the current specification requires
+that the types pointer be to non-const objects.  This restriction
+is unnecessary and unintended.
+
    
+
+
    [
+Summit:
+]
    
+
+
    
+Move to review.  Lawrence will first check with Peter whether the
+current examples are sufficient, or whether they need to be expanded to
+include all cases.
+
    
+
+
    [
+2009-07 Frankfurt
+]
    
+
+
+
    
+
    
+Lawrence will handle all issues relating to atomics in a single paper.
+
    
+
    
+LWG will defer discussion on atomics until that paper appears.
+
    
+
    
+Move to Open.
+
    
+
    
+
+
    [
+2009-08-17 Handled by
+N2925.
+]
    
+
+
+
    [
+2009-10 Santa Cruz:
+]
    
+
+
+
    
+NAD Editorial.  Solved by
+N2992.
+
    
+
+
+
+
    Proposed resolution:
    
+
    
+Add const qualification to the pointer values of the atomic_address
+and atomic<T*> specializations.  E.g.
+
    
+
+
    typedef struct atomic_address {
+   void store(const void*, memory_order = memory_order_seq_cst) volatile;
+   void* exchange( const void*, memory_order = memory_order_seq_cst) volatile;
+   bool compare_exchange( const void*&, const void*,
+                          memory_order, memory_order) volatile;
+   bool compare_exchange( const void*&, const void*,
+                          memory_order = memory_order_seq_cst ) volatile;
+   void* operator=(const void*) volatile;
+} atomic_address;
+
+void atomic_store(volatile atomic_address*, const void*);
+void atomic_store_explicit(volatile atomic_address*, const void*,
+                          memory_order);
+void* atomic_exchange(volatile atomic_address*, const void*);
+void* atomic_exchange_explicit(volatile atomic_address*, const void*,
+                              memory_order);
+bool atomic_compare_exchange(volatile atomic_address*,
+                            const void**, const void*);
+bool atomic_compare_exchange_explicit(volatile atomic_address*,
+                                     const void**, const void*,
+                                     memory_order, memory_order);
+
    
+
+
+
+
+
+
    
+
    880. Missing atomic exchange parameter
    
+
    Section: 29 [atomics] Status: NAD Editorial
+ Submitter: Lawrence Crowl Opened: 2008-08-24  Last modified: 2009-10-26
    
+
    View all other issues in [atomics].
    
+
    View all issues with NAD Editorial status.
    
+
    Duplicate of: 942
    
+
    Discussion:
    
+
    
+The atomic_exchange and atomic_exchange_explicit functions seem to
+be inconsistently missing parameters.
+
    
+
+
    [
+Post Summit:
+]
    
+
+
+
    
+
    
+Lawrence: Need to write up a list for Pete with details.
+
    
+
    
+Detlef: Should not be New, we already talked about in Concurrency group.
+
    
+
    
+Recommend Open.
+
    
+
    
+
+
    [
+2009-07 Frankfurt
+]
    
+
+
+
    
+
    
+Lawrence will handle all issues relating to atomics in a single paper.
+
    
+
    
+LWG will defer discussion on atomics until that paper appears.
+
    
+
    
+Move to Open.
+
    
+
    
+
+
    [
+2009-08-17 Handled by
+N2925.
+]
    
+
+
+
    [
+2009-10 Santa Cruz:
+]
    
+
+
+
    
+NAD Editorial.  Solved by
+N2992.
+
    
+
+
+
+
    Proposed resolution:
    
+
    
+Add the appropriate parameters.  For example,
+
    
+
+
    bool atomic_exchange(volatile atomic_bool*, bool);
+bool atomic_exchange_explicit(volatile atomic_bool*, bool, memory_order);
+
    
+
+
+
+
+
 
    
 
    884. shared_ptr swap
    
-
    Section: 20.8.10.2.4 [util.smartptr.shared.mod] Status: NAD Editorial
+
    Section: 20.8.15.2.4 [util.smartptr.shared.mod] Status: NAD Editorial
  Submitter: Jonathan Wakely Opened: 2008-09-15  Last modified: 2009-07-13
    
 
    View all issues with NAD Editorial status.
    
 
    Discussion:
    
@@ -22134,7 +25241,6 @@ Recommend NAD Editorial, fixed by
 
    892. Forward_list issues...
    
 
    Section: 23.3.3.5 [forwardlist.ops] Status: NAD Editorial
  Submitter: Ed Smith-Rowland Opened: 2008-09-15  Last modified: 2009-03-09
    
-
    View other active issues in [forwardlist.ops].
    
 
    View all other issues in [forwardlist.ops].
    
 
    View all issues with NAD Editorial status.
    
 
    Discussion:
    
@@ -22199,7 +25305,7 @@ Move to NAD Editorial, Pending. Howard to open a new issue to handle the
 problems with the complexity requirements.
 
    
 
    
-Opened 897.
+Opened 897.
 
    
 
    
 
@@ -22250,9 +25356,339 @@ clauses which are not constraints on user code, such as that on
 
 
 
+
    
+
    897. Forward_list issues... Part 2
    
+
    Section: 23.3.3.4 [forwardlist.modifiers] Status: NAD Editorial
+ Submitter: Howard Hinnant Opened: 2008-09-22  Last modified: 2009-10-20
    
+
    View all issues with NAD Editorial status.
    
+
    Discussion:
    
+
    
+This issue was split off from 892 at the request of the LWG.
+
    
+
+
    [
+San Francisco:
+]
    
+
+
+
    
+
    
+This issue is more complicated than it looks.
+
    
+
    
+paragraph 47: replace each (first, last) with (first, last]
+
    
+
    
+add a statement after paragraph 48 that complexity is O(1)
+
    
+
    
+remove the complexity statement from the first overload of splice_after
+
    
+
    
+We may have the same problems with other modifiers, like erase_after.
+Should it require that all iterators in the range (position, last] be
+dereferenceable?
+
    
+
    
+
+
    
+There are actually 3 issues here:
+
    
+
+
      
+
    1. 
+
      
+What value should erase_after return?  With list, code often
+looks like:
+
      
+
      for (auto i = l.begin(); i != l.end();)
+{
+    // inspect *i and decide if you want to erase it
+    // ...
+    if (I want to erase *i)
+        i = l.erase(i);
+    else
+        ++i;
+}
+
      
+
      
+I.e. the iterator returned from erase is useful for setting up the
+logic for operating on the next element.  For forward_list this might
+look something like:
+
      
+
      auto i = fl.before_begin();
+auto ip1 = i;
+for (++ip1; ip1 != fl.end(); ++ip1)
+{
+    // inspect *(i+1) and decide if you want to erase it
+    // ...
+    if (I want to erase *(i+1))
+        i = fl.erase_after(i);
+    else
+        ++i;
+    ip1 = i;
+}
+
      
+
      
+In the above example code, it is convenient if erase_after returns
+the element prior to the erased element (range) instead of the element
+after the erase element (range).
+
      
+
      
+Existing practice:
+
      
+
        
+
      • SGI slist returns an iterator referencing the element after the erased range.
        • 
+
      • CodeWarrior slist returns an iterator referencing the element before the erased range.
        • 
+
      
+
      
+There is not a strong technical argument for either solution over the other.
+
      
+
      2. 
+
+
    2. 
+
      
+With all other containers, operations always work on the range
+[first, last) and/or prior to the given position.
+
      
+
      
+With forward_list, operations sometimes work on the range
+(first, last] and/or after the given position.
+
      
+
      
+This is simply due to the fact that in order to operate on
+*first (with forward_list) one needs access to
+*(first-1).  And that's not practical with
+forward_list.  So the operating range needs to start with (first,
+not [first (as the current working paper says). 
+
      
+
      
+Additionally, if one is interested in  splicing the range (first, last),
+then (with forward_list), one needs practical (constant time) access to
+*(last-1) so that one can set the next field in this node to
+the proper value.  As this is not possible with forward_list, one must
+specify the last element of interest instead of one past the last element of
+interest.  The syntax for doing this is to pass (first, last] instead
+of (first, last).
+
      
+
      
+With erase_after we have a choice of either erasing the range
+(first, last] or (first, last).  Choosing the latter
+enables:
+
      
+
      x.erase_after(pos, x.end());
+
      
+
+
      
+With the former, the above statement is inconvenient or expensive due to the lack
+of constant time access to x.end()-1.  However we could introduce:
+
      
+
+
      iterator erase_to_end(const_iterator position);
+
      
+
+
      
+to compensate.
+
      
+
+
      
+The advantage of the former ((first, last]) for erase_after
+is a consistency with splice_after which uses (first, last]
+as the specified range.  But this either requires the addition of erase_to_end
+or giving up such functionality.
+
      
+
+
      3. 
+
+
    3. 
+As stated in the discussion of 892, and reienforced by point 2 above,
+a splice_after should work on the source range (first, last]
+if the operation is to be Ο(1).  When splicing an entire list x the
+algorithm needs (x.before_begin(), x.end()-1].  Unfortunately x.end()-1
+is not available in constant time unless we specify that it must be.  In order to
+make x.end()-1 available in constant time, the implementation would have
+to dedicate a pointer to it.  I believe the design of
+N2543
+intended a nominal overhead of foward_list of 1 pointer.  Thus splicing
+one entire forward_list into another can not be Ο(1).
+
      4. 
+
    
+
+
    [
+Batavia (2009-05):
+]
    
+
+
    
+
    
+We agree with the proposed resolution.
+
    
+
    
+Move to Review.
+
    
+
    
+
+
    [
+2009-07 Frankfurt
+]
    
+
+
+
    
+
    
+We may need a new issue to correct splice_after, because it may no
+longer be correct to accept an rvalues as an argument. Merge may be
+affected, too. This might be issue 1133. (Howard: confirmed)
+
    
+
    
+Move this to Ready, but the Requires clause of the second form of
+splice_after should say "(first, last)," not "(first, last]" (there are
+three occurrences). There was considerable discussion on this. (Howard: fixed)
+
    
+
    
+Alan suggested removing the "foward_last<T. Alloc>&& x"
+parameter from the second form of splice_after, because it is redundant.
+PJP wanted to keep it, because it allows him to check for bad ranges
+(i.e. "Granny knots").
+
    
+
    
+We prefer to keep x.
+
    
+
    
+Beman. Whenever we deviate from the customary half-open range in the
+specification, we should add a non-normative comment to the standard
+explaining the deviation. This clarifies the intention and spares the
+committee much confusion in the future.
+
    
+
    
+Alan to write a non-normative comment to explain the use of fully-closed ranges.
+
    
+
    
+Move to Ready, with the changes described above. (Howard: awaiting note from Alan)
+
    
+
    
+
+
    [
+2009-10 Santa Cruz:
+]
    
+
+
+
    
+NAD Editorial, addressed by
+N2988.
+
    
+
+
+
+
    Proposed resolution:
    
+
    
+Wording below assumes issue 878 is accepted, but this issue is
+independent of that issue.
+
    
+
+
    
+Change 23.3.3.4 [forwardlist.modifiers]:
+
    
+
+
    
+
    iterator erase_after(const_iterator position);
+
    
+
    
+
    
+Requires: The iterator following position is dereferenceable.
+
    
+
    
+Effects: Erases the element pointed to by the iterator following position.
+
    
+
    
+Returns: An iterator pointing to the element following the one that was erased, or end() if no such 
+element exists
+An iterator equal to position.
+
    
+
    
+
+
+
    iterator erase_after(const_iterator position, const_iterator last);
+
    
+
    
+
    
+Requires: All iterators in the range
+[(position,last)
+are dereferenceable.
+
    
+
    
+Effects: Erases the elements in the range
+[(position,last).
+
    
+
    
+Returns:  An iterator equal to position last
+
    
+
    
+
    
+
+
    
+Change 23.3.3.5 [forwardlist.ops]:
+
    
+
+
    
+
    void splice_after(const_iterator position, forward_list<T,Allocator>&& x);
+
    
+
    
+
    
+Requires: position is before_begin() or a
+dereferenceable iterator in the range [begin(), end)). &x != this.
+
    
+
    
+Effects: Inserts the contents of x after position, and
+x becomes empty. Pointers and references to 
+the moved elements of x now refer to those same elements but as members of *this.
+Iterators referring to the moved elements will continue to refer to their elements,
+but they now behave as iterators into *this, not into x. 
+
    
+
    
+Throws: Nothing. 
+
    
+
    
+Complexity: Ο(1) Ο(distance(x.begin(), x.end()))
+
    
+
    
+
+
    ...
    
+
+
    void splice_after(const_iterator position, forward_list<T,Allocator>&& x, 
+                  const_iterator first, const_iterator last);
+
    
+
    
+
    
+Requires: position is before_begin() or a
+dereferenceable iterator in the range [begin(), end)).
+(first,last) is a valid range in
+x, and all iterators in the range
+(first,last) are dereferenceable.
+position is not an iterator in the range (first,last).
+
    
+
    
+Effects: Inserts elements in the range (first,last)
+after position and removes the elements from x.
+Pointers and references to the moved elements of x now refer to
+those same elements but as members of *this. Iterators
+referring to the moved elements will continue to refer to their
+elements, but they now behave as iterators into *this, not into
+x.
+
    
+
    
+Complexity: Ο(1).
+
    
+
    
+
+
    
+
+
+
+
+
+
 
    
 
    901. insert iterators can move from lvalues
    
-
    Section: 24.7.5 [insert.iterator] Status: NAD
+
    Section: 24.5.2.5 [insert.iterator] Status: NAD
  Submitter: Alisdair Meredith Opened: 2008-09-24  Last modified: 2009-07-13
    
 
    View all issues with NAD status.
    
 
    Discussion:
    
@@ -22378,7 +25814,7 @@ treatment of axioms in clause 14.
 
 
    
 
    903. back_insert_iterator issue
    
-
    Section: 24.7.1 [back.insert.iterator] Status: NAD
+
    Section: 24.5.2.1 [back.insert.iterator] Status: NAD
  Submitter: Dave Abrahams Opened: 2008-09-19  Last modified: 2009-07-16
    
 
    View all issues with NAD status.
    
 
    Discussion:
    
@@ -22422,7 +25858,7 @@ Move to NAD.
 
 
      
 
    1. 
-If 1009 is accepted, OutputIterator does no longer support post increment.
+If 1009 is accepted, OutputIterator does no longer support post increment.
 
      2. 
 
    2. 
 To support backward compatibility a second overload of operator*
@@ -22446,7 +25882,6 @@ to properly reflect the dual nature of built-in operator* as of
 
      905. Mutex specification questions
      
 
      Section: 30.4.1.1 [thread.mutex.class] Status: Dup
  Submitter: Herb Sutter Opened: 2008-09-18  Last modified: 2009-03-22
      
-
      View other active issues in [thread.mutex.class].
      
 
      View all other issues in [thread.mutex.class].
      
 
      View all issues with Dup status.
      
 
      Duplicate of: 893
      
@@ -22662,9 +26097,97 @@ constraint "ValueType".
 
 
 
+
      
+
      908. Deleted assignment operators for atomic types must be volatile
      
+
      Section: 29.5 [atomics.types] Status: NAD Editorial
+ Submitter: Anthony Williams Opened: 2008-09-26  Last modified: 2009-10-26
      
+
      View all other issues in [atomics.types].
      
+
      View all issues with NAD Editorial status.
      
+
      Discussion:
      
+
+
      Addresses US 90
      
+
+
      
+The deleted copy-assignment operators for the atomic types are not
+marked as volatile in N2723, whereas the assignment operators from the
+associated non-atomic types are. e.g.
+
      
+
      atomic_bool& operator=(atomic_bool const&) = delete;
+atomic_bool& operator=(bool) volatile;
+
      
+
+
      
+This leads to ambiguity when assigning a non-atomic value to a
+non-volatile instance of an atomic type:
+
      
+
      atomic_bool b;
+b=false;
+
      
+
+
      
+Both assignment operators require a standard conversions: the
+copy-assignment operator can use the implicit atomic_bool(bool)
+conversion constructor to convert false to an instance of
+atomic_bool, or b can undergo a qualification conversion in order to
+use the assignment from a plain bool.
+
      
+
+
      
+This is only a problem once issue 845 is applied.
+
      
+
+
      [
+Summit:
+]
      
+
+
      
+Move to open. Assign to Lawrence. Related to US 90 comment.
+
      
+
+
      [
+2009-08-17 Handled by
+N2925.
+]
      
+
+
+
      [
+2009-10 Santa Cruz:
+]
      
+
+
+
      
+NAD Editorial.  Solved by
+N2992.
+
      
+
+
+
+
      Proposed resolution:
      
+
      
+Add volatile qualification to the deleted copy-assignment operator of
+all the atomic types:
+
      
+
+
      atomic_bool& operator=(atomic_bool const&) volatile = delete;
+atomic_itype& operator=(atomic_itype const&) volatile = delete;
+
      
+
+
      
+etc.
+
      
+
      
+This will mean that the deleted copy-assignment operator will require
+two conversions in the above example, and thus be a worse match than
+the assignment from plain bool.
+
      
+
+
+
+
+
 
      
 
      912. Array swap needs to be conceptualized
      
-
      Section: 25.4.3 [alg.swap] Status: NAD Concepts
+
      Section: 25.3.3 [alg.swap] Status: NAD Concepts
  Submitter: Daniel Krügler Opened: 2008-10-01  Last modified: 2009-07-13
      
 
      View all other issues in [alg.swap].
      
 
      View all issues with NAD Concepts status.
      
@@ -22695,7 +26218,7 @@ Move to NAD; the changes have already been made.
 
 
      Proposed resolution:
      
 
      
-Replace in 25.4.3 [alg.swap] before p. 3 until p. 4 by
+Replace in 25.3.3 [alg.swap] before p. 3 until p. 4 by
 
      
 
 
      template <class ValueType T, size_t N>
@@ -22719,13 +26242,13 @@ void swap(T (&a)[N], T (&b)[N]);
 
 
      
 
      913. Superfluous requirements for replace algorithms
      
-
      Section: 25.4.5 [alg.replace] Status: NAD Concepts
+
      Section: 25.3.5 [alg.replace] Status: NAD Concepts
  Submitter: Daniel Krügler Opened: 2008-10-03  Last modified: 2009-07-14
      
 
      View all other issues in [alg.replace].
      
 
      View all issues with NAD Concepts status.
      
 
      Discussion:
      
 
      
-(A) 25.4.5 [alg.replace]/1:
+(A) 25.3.5 [alg.replace]/1:
 
      
 
 
      
@@ -22733,7 +26256,7 @@ void swap(T (&a)[N], T (&b)[N]);
 
      
 
 
      
-(B) 25.4.5 [alg.replace]/4:
+(B) 25.3.5 [alg.replace]/4:
 
      
 
 
      
@@ -22780,7 +26303,7 @@ Move to Tentatively Ready.
 
        
 
      1. 
 
        
-Remove 25.4.5 [alg.replace]/1.
+Remove 25.3.5 [alg.replace]/1.
 
        
 
        template<ForwardIterator Iter, class T> 
   requires OutputIterator<Iter, Iter::reference> 
@@ -22803,7 +26326,7 @@ template<ForwardIterator Iter, Predicate<auto, Iter::value_type> Pred,
 
        2. 
 
      2. 
 
        
-25.4.5 [alg.replace]/4: Remove the sentence "The results of the
+25.3.5 [alg.replace]/4: Remove the sentence "The results of the
 expressions *first and
 new_value shall be writable to the result output iterator.".
 
        
@@ -22840,13 +26363,13 @@ iterator. The ranges [first,last) and [result,result +
 
 
        
 
        914. Superfluous requirement for unique
        
-
        Section: 25.4.9 [alg.unique] Status: NAD Concepts
+
        Section: 25.3.9 [alg.unique] Status: NAD Concepts
  Submitter: Daniel Krügler Opened: 2008-10-03  Last modified: 2009-07-14
        
 
        View all other issues in [alg.unique].
        
 
        View all issues with NAD Concepts status.
        
 
        Discussion:
        
 
        
-25.4.9 [alg.unique]/2: "Requires: The comparison function shall be an
+25.3.9 [alg.unique]/2: "Requires: The comparison function shall be an
 equivalence relation."
 
        
 
@@ -22873,7 +26396,7 @@ Move to Tentatively Ready.
 
 
        Proposed resolution:
        
 
        
-Remove 25.4.9 [alg.unique]/2
+Remove 25.3.9 [alg.unique]/2
 
        
 
 
        template<ForwardIterator Iter>
@@ -22901,9 +26424,214 @@ template<ForwardIterator Iter, EquivalenceRelation<auto, Iter::value_type&
 
 
 
+
        
+
        916. Redundant move-assignment operator of pair should be removed
        
+
        Section: 20.3.4 [pairs] Status: NAD
+ Submitter: Daniel Krügler Opened: 2008-10-04  Last modified: 2009-10-23
        
+
        View other active issues in [pairs].
        
+
        View all other issues in [pairs].
        
+
        View all issues with NAD status.
        
+
        Discussion:
        
+
        see also 917.
        
+
+
        
+The current WP provides the following assignment operators for pair
+in 20.3.4 [pairs]/1:
+
        
+
+
          
+
        1. 
+
          template<class U , class V>
+requires HasAssign<T1, const U&> && HasAssign<T2, const V&>
+pair& operator=(const pair<U , V>& p);
+
          
+
          2. 
+
        2. 
+
          requires MoveAssignable<T1> && MoveAssignable<T2> pair& operator=(pair&& p );
+
          
+
          3. 
+
        3. 
+
          template<class U , class V>
+requires HasAssign<T1, RvalueOf<U>::type> && HasAssign<T2, RvalueOf<V>::type>
+pair& operator=(pair<U , V>&& p);
+
          
+
          4. 
+
        
+
+
        
+It seems that the functionality of (2) is completely covered by (3), therefore
+(2) should be removed.
+
        
+
+
        [
+Batavia (2009-05):
+]
        
+
+
        
+
        
+Bill believes the extra assignment operators are necessary for resolving
+ambiguities, but that does not mean it needs to be part of the specification.
+
        
+
        
+Move to Open.
+We recommend this be looked at in the context of the ongoing work
+related to the pair templates.
+
        
+
        
+
+
        [
+2009-07 Frankfurt:
+]
        
+
+
+
        
+Leave this open pending the removal of concepts from the WD.
+
        
+
+
        [
+2009-10 Santa Cruz:
+]
        
+
+
+
        
+Mark as NAD, see issue 801.
+
        
+
+
+
+
        Proposed resolution:
        
+
          
+
        1. 
+
          
+In 20.3.4 [pairs] p. 1, class pair and just before p. 13 remove the declaration:
+
          
+
+
          requires MoveAssignable<T1> && MoveAssignable<T2> pair& operator=(pair&& p );
+
          
+
          2. 
+
+
        2. 
+Remove p.13+p.14
+
          3. 
+
+
        
+
+
+
+
+
+
        
+
        917. Redundant move-assignment operator of tuple should be removed
        
+
        Section: 20.5.2.1 [tuple.cnstr] Status: NAD
+ Submitter: Daniel Krügler Opened: 2008-10-04  Last modified: 2009-10-23
        
+
        View all other issues in [tuple.cnstr].
        
+
        View all issues with NAD status.
        
+
        Discussion:
        
+
        see also 916.
        
+
        
+N2770 (and thus now the WP) removed the
+non-template move-assignment operator from tuple's class definition,
+but the latter individual member description does still provide this
+operator. Is this (a) an oversight and can it (b) be solved as part of an
+editorial process?
+
        
+
+
        [
+Post Summit Daniel provided wording.
+]
        
+
+
+
        [
+Batavia (2009-05):
+]
        
+
+
        
+
        
+We believe that the proposed resolution's part 1 is editorial.
+
        
+
        
+Regarding part 2, we either remove the specification as proposed,
+or else add back the declaration to which the specification refers.
+Alisdair and Bill prefer the latter.
+It is not immediately obvious whether the function is intended to be present.
+
        
+
        
+We recommend that the Project Editor restore the missing declaration
+and that we keep part 2 of the issue alive.
+
        
+
        
+Move to Open.
+
        
+
        
+
+
        [
+2009-07 Frankfurt:
+]
        
+
+
+
        
+Leave this open pending the removal of concepts from the WD.
+
        
+
+
        [
+2009-10 Santa Cruz:
+]
        
+
+
+
        
+Mark as NAD, see issue 801.
+
        
+
+
+
+
        Proposed resolution:
        
+
          
+
        1. 
+
          
+In 20.5.2 [tuple.tuple], class tuple just before member swap please
+change as indicated:
+
          
+
          [
+This fixes an editorial loss between N2798 to N2800
+]
          
+
+
          template <class... UTypes>
+requires HasAssign<Types, const UTypes&>...
+tuple& operator=(const pair<UTypes...>&);
+
+template <class... UTypes>
+requires HasAssign<Types, RvalueOf<UTypes>::type>...
+tuple& operator=(pair<UTypes...>&&);
+
          
+
          2. 
+
        2. 
+
          
+In 20.5.2.1 [tuple.cnstr], starting just before p. 11 please remove
+as indicated:
+
          
+
+
          requires MoveAssignable<Types>... tuple& operator=(tuple&& u);
+
          
+
          
+
          
+-11- Effects: Move-assigns each element of u to the corresponding
+element of *this.
+
          
+
          
+-12- Returns: *this.
+
          
+
          
+
          
+
          3. 
+
        
+
+
+
+
+
 
        
 
        918. Swap for tuple needs to be conceptualized
        
-
        Section: 20.5.2.6 [tuple.swap] Status: NAD Concepts
+
        Section: 20.5.2.3 [tuple.swap] Status: NAD Concepts
  Submitter: Daniel Krügler Opened: 2008-10-04  Last modified: 2009-07-13
        
 
        View all issues with NAD Concepts status.
        
 
        Discussion:
        
@@ -22956,7 +26684,7 @@ Move to NAD.
 
          
 
        1. 
 
          
-In both 20.5.1 [tuple.general]/2 and 20.5.2.7 [tuple.special] change
+In both 20.5.1 [tuple.general]/2 and 20.5.2.9 [tuple.special] change
 
          
 
 
          template <class Swappable... Types>
@@ -22968,7 +26696,7 @@ void swap(tuple<Types...>& x, tuple<Types...>& y);
 
        2. 
 
          
 In 20.5.2 [tuple.tuple], class tuple definition and in
-20.5.2.6 [tuple.swap], change
+20.5.2.3 [tuple.swap], change
 
          
 
 
          requires Swappable<Types>...void swap(tuple&);
@@ -22978,7 +26706,7 @@ In 20.5.2 [tuple.tuple], class tuple definition and in
 
 
        3. 
 
          
-In 20.5.2.6 [tuple.swap] remove the current requires-clause, which says:
+In 20.5.2.3 [tuple.swap] remove the current requires-clause, which says:
 
          
 
 
          
@@ -22993,14 +26721,501 @@ In 20.5.2.6 [tuple.swap] remove the current requires-clause, which says:
 
 
 
+
          
+
          919. (forward_)list specialized remove algorithms are over constrained
          
+
          Section: 23.3.3.5 [forwardlist.ops], 23.3.4.4 [list.ops] Status: NAD
+ Submitter: Daniel Krügler Opened: 2008-10-06  Last modified: 2009-10-23
          
+
          View all other issues in [forwardlist.ops].
          
+
          View all issues with NAD status.
          
+
          Discussion:
          
+
          
+The signatures of forwardlist::remove and list::remove
+defined in 23.3.3.5 [forwardlist.ops] before 11 + 23.3.4.4 [list.ops] before 15:
+
          
+
+
          requires EqualityComparable<T> void remove(const T& value);
+
          
+
+
          
+are asymmetric to their predicate variants (which only require
+Predicate, not EquivalenceRelation) and with the free algorithm
+remove (which only require HasEqualTo). Also, nothing in the
+pre-concept WP
+N2723
+implies that EqualityComparable should
+be the intended requirement.
+
          
+
+
          [
+Batavia (2009-05):
+]
          
+
+
          
+
          
+We agree with the proposed resolution,
+but would like additional input from concepts experts.
+
          
+
          
+Move to Review.
+
          
+
          
+
+
          [
+2009-07-21 Alisdair adds:
+]
          
+
+
+
          
+Current rationale and wording for this issue is built around concepts. I
+suggest the issue reverts to Open status. I believe there is enough of
+an issue to review after concepts are removed from the WP to re-examine
+the issue in Santa Cruz, rather than resolve as NAD Concepts.
+
          
+
+
          [
+2009-10-10 Daniel adds:
+]
          
+
+
+
          
+Recommend NAD: The concept-free wording as of
+N2960
+has no longer the
+over-specified requirement
+EqualityComparable for the remove function that uses ==. In fact, now
+the same test conditions exists
+as for the free algorithm remove (25.3.8 [alg.remove]). The error was
+introduced in the process of conceptifying.
+
          
+
+
          [
+2009-10 Santa Cruz:
+]
          
+
+
+
          
+NAD, solved by the removal of concepts.
+
          
+
+
+
+
          Proposed resolution:
          
+
            
+
          1. 
+
            
+Replace in 23.3.3.5 [forwardlist.ops] before 11 and in 23.3.4.4 [list.ops] before 15
+
            
+
+
            requires EqualityComparable<T> HasEqualTo<T, T> void remove(const T& value);
+
            
+
            2. 
+
          
+
+
+
+
+
+
+
          
+
          923. atomics with floating-point 
          
+
          Section: 29 [atomics] Status: NAD Editorial
+ Submitter: Herb Sutter Opened: 2008-10-17  Last modified: 2009-10-26
          
+
          View all other issues in [atomics].
          
+
          View all issues with NAD Editorial status.
          
+
          Discussion:
          
+
          
+Right now, C++0x doesn't have atomic<float>. We're thinking of adding
+the words to support it for TR2 (note: that would be slightly
+post-C++0x). If we need it, we could probably add the words.
+
          
+
          
+Proposed resolutions: Using atomic<FP>::compare_exchange (weak or
+strong) should be either:
+
          
+
+
            
+
          1. 
+ill-formed, or
+
            2. 
+
          2. 
+well-defined.
+
            3. 
+
          
+
+
          
+I propose Option 1 for C++0x for expediency. If someone wants to argue
+for Option 2, they need to say what exactly they want compare_exchange
+to mean in this case (IIRC, C++0x doesn't even assume IEEE 754).
+
          
+
+
          [
+Summit:
+]
          
+
+
+
          
+Move to open. Blocked until concepts for atomics are addressed.
+
          
+
+
          [
+Post Summit Anthony adds:
+]
          
+
+
+
          
+
          
+Recommend NAD. C++0x does have std::atomic<float>, and both
+compare_exchange_weak and compare_exchange_strong are well-defined in
+this case. Maybe change the note in 29.6 [atomics.types.operations] paragraph 20 to:
+
          
+
+
          
+
          
+[Note: The effect of the compare-and-exchange operations is
+
          
+
          if (!memcmp(object,expected,sizeof(*object)))
+    *object = desired;
+else
+    *expected = *object;
+
          
+
+
          
+This may result in failed comparisons for values that compare equal if
+the underlying type has padding bits or alternate representations of
+the same value. -- end note]
+
          
+
          
+
+
          
+
+
          [
+2009-10 Santa Cruz:
+]
          
+
+
+
          
+NAD Editorial.  Solved by
+N2992.
+
          
+
+
+
+
          Proposed resolution:
          
+
          
+Change the note in 29.6 [atomics.types.operations] paragraph 20 to:
+
          
+
+
          
+
          
+[Note: The effect of the compare-and-exchange operations is
+
          
+
          if (*object == *expected !memcmp(object,expected,sizeof(*object)))
+    *object = desired;
+else
+    *expected = *object;
+
          
+
+
          
+This may result in failed comparisons for values that compare equal if
+the underlying type has padding bits or alternate representations of
+the same value. -- end note]
+
          
+
          
+
+
+
+
+
+
+
          
+
          924. structs with internal padding
          
+
          Section: 29 [atomics] Status: NAD Editorial
+ Submitter: Herb Sutter Opened: 2008-10-17  Last modified: 2009-10-26
          
+
          View all other issues in [atomics].
          
+
          View all issues with NAD Editorial status.
          
+
          Discussion:
          
+
          
+Right now, the compare_exchange_weak loop should rapidly converge on the
+padding contents. But compare_exchange_strong will require a bit more
+compiler work to ignore padding for comparison purposes.
+
          
+
          
+Note that this isn't a problem for structs with no padding, and we do
+already have one portable way to ensure that there is no padding that
+covers the key use cases: Have elements be the same type. I suspect that
+the greatest need is for a structure of two pointers, which has no
+padding problem. I suspect the second need is a structure of a pointer
+and some form of an integer. If that integer is intptr_t, there will be
+no padding.
+
          
+
          
+Related but separable issue: For unused bitfields, or other unused
+fields for that matter, we should probably say it's the programmer's
+responsibility to set them to zero or otherwise ensure they'll be
+ignored by memcmp.
+
          
+
+
          
+Proposed resolutions: Using
+atomic<struct-with-padding>::compare_exchange_strong should be either:
+
          
+
+
            
+
          1. 
+ill-formed, or
+
            2. 
+
          2. 
+well-defined.
+
            3. 
+
          
+
+
          
+I propose Option 1 for C++0x for expediency, though I'm not sure how to
+say it. I would be happy with Option 2, which I believe would mean that
+compare_exchange_strong would be implemented to avoid comparing padding
+bytes, or something equivalent such as always zeroing out padding when
+loading/storing/comparing. (Either implementation might require compiler
+support.)
+
          
+
+
          [
+Summit:
+]
          
+
+
+
          
+Move to open. Blocked until concepts for atomics are addressed.
+
          
+
+
          [
+Post Summit Anthony adds:
+]
          
+
+
+
          
+The resoultion of LWG 923 should resolve this issue as well.
+
          
+
+
          [
+2009-10 Santa Cruz:
+]
          
+
+
+
          
+NAD Editorial.  Solved by
+N2992.
+
          
+
+
+
+
          Proposed resolution:
          
+
          
+
          
+
+
+
+
+
+
          
+
          926. Sequentially consistent fences, relaxed operations and modification order
          
+
          Section: 29.3 [atomics.order] Status: NAD Editorial
+ Submitter: Anthony Williams Opened: 2008-10-19  Last modified: 2009-10-26
          
+
          View all other issues in [atomics.order].
          
+
          View all issues with NAD Editorial status.
          
+
          Discussion:
          
+
          Addresses UK 313
          
+
+
          
+There was an interesting issue raised over on comp.programming.threads
+today regarding the following example
+
          
+
+
          // Thread 1:
+x.store(1, memory_order_relaxed);           // SX
+atomic_thread_fence(memory_order_seq_cst);  // F1
+y.store(1, memory_order_relaxed);           // SY1
+atomic_thread_fence(memory_order_seq_cst);  // F2
+r1 = y.load(memory_order_relaxed);          // RY
+
+// Thread 2:
+y.store(0, memory_order_relaxed);          // SY2
+atomic_thread_fence(memory_order_seq_cst); // F3
+r2 = x.load(memory_order_relaxed);         // RX
+
          
+
+
          
+is the outcome r1 == 0 and r2 == 0 possible?
+
          
+
          
+I think the intent is that this is not possible, but I am not sure the
+wording guarantees that. Here is my analysis:
+
          
+
          
+Since all the fences are SC, there must be a total order between them.
+F1 must be before F2 in that order since they are in
+the same thread. Therefore F3 is either before F1,
+between F1 and F2 or after F2.
+
          
+
          
+If F3 is after F2, then we can apply 29.3 [atomics.order]p5 from
+N2798:
+
          
+
+
          
+For atomic operations A and B on an atomic object
+M, where A modifies M and B takes
+its value, if there are memory_order_seq_cst fences X
+and Y such that A is sequenced before X,
+Y is sequenced before B, and X precedes
+Y in S, then B observes either the effects of
+A or a later modification of M in its modification
+order.
+
          
+
+
          
+In this case, A is SX, B is RX, the
+fence X is F2 and the fence Y is F3,
+so RX must see 1.
+
          
+
          
+If F3 is before F2, this doesn't apply, but
+F3 can therefore be before or after F1.
+
          
+
          
+If F3 is after F1, the same logic applies, but this
+time the fence X is F1. Therefore again, RX
+must see 1.
+
          
+
          
+Finally we have the case that F3 is before F1
+in the SC ordering. There are now no guarantees about RX, and
+RX can see r2==0.
+
          
+
          
+We can apply 29.3 [atomics.order]p5 again. This time,
+A is SY2, B is RY, X is
+F3 and Y is F1. Thus RY must observe
+the effects of SY2 or a later modification of y in its
+modification order.
+
          
+
          
+Since SY1 is sequenced before RY, RY must
+observe the effects of SY1 or a later modification of
+y in its modification order.
+
          
+
          
+In order to ensure that RY sees (r1==1), we must see
+that SY1 is later in the modification order of y than
+SY2.
+
          
+
          
+We're now skating on thin ice. Conceptually, SY2 happens-before
+F3, F3 is SC-ordered before F1, F1
+happens-before SY1, so SY1 is later in the
+modification order M of y, and RY must see
+the result of SY1 (r1==1). However, I don't think the
+words are clear on that.
+
          
+
+
          [
+Post Summit Hans adds:
+]
          
+
+
+
          
+
          
+In my (Hans') view, our definition of fences will always be weaker than
+what particular hardware will guarantee.  Memory_order_seq_cst fences
+inherently don't guarantee sequential consistency anyway, for good
+reasons (e.g. because they can't enforce a total order on stores).
+ Hence I don't think the issue demonstrates a gross failure to achieve
+what we intended to achieve.  The example in question is a bit esoteric.
+ Hence, in my view, living with the status quo certainly wouldn't be a
+disaster either.
+
          
+
          
+In any case, we should probably add text along the lines of the
+following between p5 and p6 in 29.3 [atomics.order]:
+
          
+
          
+[Note: Memory_order_seq_cst only ensures sequential consistency for a
+data-race-free program that uses exclusively memory_order_seq_cst
+operations.  Any use of weaker ordering will invalidate this guarantee
+unless extreme care is used.  In particular, memory_order_seq_cst fences
+only ensure a total order for the fences themselves.  They cannot, in
+general, be used to restore sequential consistency for atomic operations
+with weaker ordering specifications.]
+
          
+
+
          
+Also see thread beginning at c++std-lib-23271.
+
          
+
+
          
+
+
          [
+Herve's correction:
+]
          
+
+
          
+
          
+Minor point, and sorry for the knee jerk reaction: I admit to having
+no knowledge of Memory_order_seq_cst, but my former boss (John Lakos)
+has ingrained an automatic introspection on the use of "only".   I
+think you meant:
+
          
+
+
          
+[Note: Memory_order_seq_cst ensures sequential consistency only
+for . . . .  In particular, memory_order_seq_cst fences ensure a
+total order only for . . .
+
          
+
          
+Unless, of course, Memory_order_seq_cst really do nothing but ensure
+sequential consistency for a data-race-free program that uses
+exclusively memory_order_seq_cst operations.
+
          
+
          
+
+
          [
+2009-10 Santa Cruz:
+]
          
+
+
+
          
+NAD Editorial.  Solved by
+N2992.
+
          
+
+
+
+
          Proposed resolution:
          
+
          
+Add a new paragraph after 29.3 [atomics.order]p5 that says
+
          
+
+
          
+For atomic operations A and B on an atomic object
+M, where A and B modify M, if there
+are memory_order_seq_cst fences X and Y such
+that A is sequenced before X, Y is sequenced
+before B, and X precedes Y in S,
+then B occurs later than A in the modifiction order of
+M.
+
          
+
+
+
+
+
 
          
 
          927. Dereferenceable  should be HasDereference
          
-
          Section: 20.8.2.2 [allocator.concepts] Status: NAD Concepts
+
          Section: X [allocator.concepts] Status: NAD Concepts
  Submitter: Pablo Halpern Opened: 2008-10-23  Last modified: 2009-07-13
          
 
          View all issues with NAD Concepts status.
          
 
          Discussion:
          
 
          
-20.8.2.2 [allocator.concepts] contains a reference to a concept named
+X [allocator.concepts] contains a reference to a concept named
 Dereferenceable. No such concept exists.
 
          
 
@@ -23035,7 +27250,7 @@ Move to NAD Editorial.
 
          Proposed resolution:
          
 
          
 Change all uses of the concept Dereferenceable to
-HasDereference in 20.8.2.2 [allocator.concepts].
+HasDereference in X [allocator.concepts].
 
          
 
 
@@ -23044,7 +27259,7 @@ Change all uses of the concept Dereferenceable to
 
 
          
 
          928. Wrong concepts used for tuple's comparison operators
          
-
          Section: 20.5.2.5 [tuple.rel] Status: NAD Concepts
+
          Section: 20.5.2.7 [tuple.rel] Status: NAD Concepts
  Submitter: Joe Gottman Opened: 2008-10-28  Last modified: 2009-07-13
          
 
          View all other issues in [tuple.rel].
          
 
          View all issues with NAD Concepts status.
          
@@ -23106,7 +27321,7 @@ Recommend Tentatively Ready.
 
 
          Proposed resolution:
          
 
          
-In 20.5.1 [tuple.general] and 20.5.2.5 [tuple.rel] change:
+In 20.5.1 [tuple.general] and 20.5.2.7 [tuple.rel] change:
 
          
 
 
          template<class... TTypes, class... UTypes>
@@ -23138,11 +27353,686 @@ template<class... TTypes, class... UTypes>
 
 
 
+
          
+
          930. Access to std::array data as built-in array type
          
+
          Section: 23.3.1 [array] Status: NAD
+ Submitter: Niels Dekker Opened: 2008-11-17  Last modified: 2009-10-20
          
+
          View all other issues in [array].
          
+
          View all issues with NAD status.
          
+
          Discussion:
          
+
+
          
+The Working Draft (N2798) allows access to the elements of
+std::array by its data() member function:
+
          
+
+
          
+
+
          23.2.1.4 array::data [array.data]
          
+
           T *data();
+ const T *data() const;
+
          
+
          1. 
+ Returns: elems.
+
          
+
          
+
+
          
+Unfortunately, the result of std::array::data() cannot be bound
+to a reference to a built-in array of the type of array::elems.
+And std::array provides no other way to get a reference to
+array::elems. 
+This hampers the use of std::array, for example when trying to
+pass its data to a C style API function:
+
          
+
+
           // Some C style API function. 
+ void set_path( char (*)[MAX_PATH] );
+
+ std::array<char,MAX_PATH> path;
+ set_path( path.data() );  // error
+ set_path( &(path.data()) );  // error
+
          
+
+ 
          
+Another example, trying to pass the array data to an instance of another
+C++ class:
+
          
+
+
           // Represents a 3-D point in space.
+ class three_d_point {
+ public:
+   explicit three_d_point(const double (&)[3]); 
+ };
+
+ const std::array<double,3> coordinates = { 0, 1, 2 };
+ three_d_point point1( coordinates.data() );  // error.
+ three_d_point point2( *(coordinates.data()) );  // error.
+
          
+
+
          
+A user might be tempted to use std::array::elems instead, but
+doing so isn't recommended, because std::array::elems is "for
+exposition only".  Note that Boost.Array users might already use
+boost::array::elems, as its documentation doesn't explicitly
+state that boost::array::elems is for exposition only:
+http://www.boost.org/doc/libs/1_36_0/doc/html/boost/array.html
+
          
+
          
+I can think of three options to solve this issue:
+
          
+
          1. 
+Remove the words "exposition only" from the definition of
+std::array::elems, as well as the note saying that "elems is
+shown for exposition only."
+
          2. 
+Change the signature of std::array::data(), so that it would
+return a reference to the built-in array, instead of a pointer to its
+first element.
+
          3. 
+Add extra member functions, returning a reference to the built-in array.
+
          
+
          
+Lawrence Crowl wrote me that it might be better to leave
+std::array::elems "for exposition only", to allow alternate
+representations to allocate the array data dynamically.  This might be
+of interest to the embedded community, having to deal with very limited
+stack sizes.
+
          
+
          
+The second option, changing the return type of
+std::array::data(), would break backward compatible to current
+Boost and TR1 implementations, as well as to the other contiguous
+container (vector and string) in a very subtle way.
+For example, the following call to std::swap currently swap two
+locally declared pointers (data1, data2), for any container
+type T that has a data() member function. When
+std::array::data() is changed to return a reference, the
+std::swap call may swap the container elements instead.
+
          
+
+
           template <typename T>
+ void func(T& container1, T& container2)
+ {
+   // Are data1 and data2 pointers or references?
+   auto data1 = container1.data();
+   auto data2 = container2.data();
+
+   // Will this swap two local pointers, or all container elements?
+   std::swap(data1, data2);
+ }
+
          
+
+
          
+The following concept is currently satisfied by all contiguous
+containers, but it no longer is for std::array, when
+array::data()
+is changed to return a reference (tested on ConceptGCC Alpha 7):
+
          
+
+
           auto concept ContiguousContainerConcept<typename T>
+ {
+   typename value_type = typename T::value_type;
+   const value_type * T::data() const;
+ }
+
          
+
+
          
+Still it's worth considering having std::array::data() return a
+reference, because it might be the most intuitive option, from a user's
+point of view.  Nicolai Josuttis (who wrote boost::array)
+mailed me that he very much prefers this option.
+
          
+
          
+Note that for this option, the definition of data() would also
+need to be revised for zero-sized arrays, as its return type cannot be a
+reference to a zero-sized built-in array.  Regarding zero-sized array,
+data() could throw an exception.  Or there could be a partial
+specialization of std::array where data() returns
+T* or gets removed.
+
          
+
          
+Personally I prefer the third option, adding a new member function to
+std::array, overloaded for const and non-const access,
+returning a reference to the built-in array, to avoid those compatible
+issues. I'd propose naming the function std::array::c_array(),
+which sounds intuitive to me. Note that boost::array already
+has a c_array() member, returning a pointer, but Nicolai told
+me that this one is only there for historical reasons. (Otherwise a name
+like std::array::native_array() or
+std::array::builtin_array() would also be fine with me.) 
+According to my proposed resolution, a zero-sized std::array does not need
+to have c_array(), while it is still required to have
+data() functions.
+
          
+
+
          [
+Post Summit:
+]
          
+
+
+
          
+
+
          
+Alisdair: Don't like p4 suggesting implementation-defined behaviour.
+
          
+
          
+Walter: What about an explicit conversion operator, instead of adding
+the new member function?
+
          
+
          
+Alisdair: Noodling about:
+
          
+
          template<size_t N, ValueType T>
+struct array
+{
+  T elems[N];
+
+// fantasy code starts here
+
+// crazy decltype version for grins only
+//requires True<(N>0)>
+//explict operator decltype(elems) & () { return elems; }
+
+// conversion to lvalue ref
+requires True<(N>0)>
+explict operator T(&)[N] () & { return elems; }
+
+// conversion to const lvalue ref
+requires True<(N>0)>
+explict operator const T(&)[N] () const & { return elems; }
+
+// conversion to rvalue ref using ref qualifiers
+requires True<(N>0)>
+explict operator T(&&)[N] () && { return elems; }
+
+// fantasy code ends here
+
+explicit operator bool() { return true; }
+};
+
          
+
+
          
+This seems legal but odd. Jason Merrill says currently a CWG issue 613
+on the non-static data member that fixes the error that current G++
+gives for the non-explicit, non-conceptualized version of this. Verdict
+from human compiler: seems legal.
+
          
+
          
+Some grumbling about zero-sized arrays being allowed and supported.
+
          
+
          
+Walter: Would this address the issue? Are we inclined to go this route?
+
          
+
          
+Alan: What would usage look like?
+
          
+
          // 3-d point in space
+struct three_d_point
+{
+  explicit three_d_point(const double (&)[3]);
+};
+
+void sink(double*);
+
+const std::array<double, 3> coordinates = { 0, 1, 2 };
+three_d_point point1( coordinates.data() ); //error
+three_d_point point2( *(coordinates.data()) ); // error
+three_d_point point3( coordinates ); // yay!
+
+sink(cooridinates); // error, no conversion
+
          
+
+
          
+Recommended Open with new wording. Take the required clause and add the
+explicit conversion operators, not have a typedef. At issue still is use
+decltype or use T[N]. In favour of using T[N], even though use of
+decltype is specially clever.
+
          
+
+
          
+
+
          [
+Post Summit, further discussion in the thread starting with c++std-lib-23215.
+]
          
+
+
+
          [
+2009-07 post-Frankfurt (Saturday afternoon group):
+]
          
+
+
+
          
+
          
+The idea to resolve the issue by adding explicit conversion operators
+was abandoned, because it would be inconvenient to use, especially when
+passing the array to a template function, as mentioned by Daniel. So we
+reconsidered the original proposed resolution, which appeared
+acceptable, except for its proposed changes to 23.3.1.6 [array.zero], which
+allowed c_array_type and c_array() to be absent for a zero-sized array.
+Alisdair argued that such wording would disallow certain generic use
+cases. New wording for 23.3.1.6 [array.zero] was agreed upon (Howard: and
+is reflected in the proposed resolution).
+
          
+
          
+Move to Review
+
          
+
          
+
+
          [
+2009-07-31 Alisdair adds:
+]
          
+
+
+
          
+
          
+I will be unhappy voting the proposed resolution for 930 past review
+until we have implementation experience with reference qualifiers. 
+Specifically, I want to understand the impact of the missing overload
+for const && (if any.)
+
          
+
+
          
+If we think the issue is important enough it might be worthwhile
+stripping the ref qualifiers for easy progress next meeting, and opening
+yet another issue to put them back with experience.
+
          
+
+
          
+Recommend deferring any decision on splitting the issue until we get LWG
+feedback next meeting - I may be the lone dissenting voice if others are
+prepared to proceed without it.
+
          
+
          
+
+
          [
+2009-10 Santa Cruz:
+]
          
+
+
+
          
+Mark as NAD. There was not enough consensus that this was sufficiently
+useful. There are known other ways to do this, such as small inline
+conversion functions.
+
          
+
+
+
+
          Proposed resolution:
          
+
          
+Add to the template definition of array, 23.3.1 [array]/3:
+
          
+
+
          
+
          
+typedef T c_array_type[N];
+c_array_type & c_array() &;
+c_array_type && c_array() &&;
+const c_array_type & c_array() const &;
+
+
          
+
          
+
+
          
+Add the following subsection to 23.3.1 [array], after 23.3.1.4 [array.data]:
+
          
+
+
          
+
          23.2.1.5 array::c_array [array.c_array]
          
+    
          
+c_array_type & c_array() &;
+c_array_type && c_array() &&;
+const c_array_type & c_array() const &;
+
          
+
          
+
          
+Returns: elems.
+
          
+
          
+
+
          
+
+
+
+
          
+Change Zero sized arrays 23.3.1.6 [array.zero]:
+
          
+
+
          
+
+
          -2- ...
          
+
+
          
+The type c_array_type is unspecified for a zero-sized array.
+
          
+
+
          
+-3- The effect of calling c_array(), front(), or
+back() for a zero-sized array is implementation defined.
+
          
+
          
+
+
+
+
+
+
+
          
+
          933. Unique_ptr defect
          
+
          Section: 20.8.14.2.5 [unique.ptr.single.modifiers] Status: NAD Future
+ Submitter: Alisdair Meredith Opened: 2008-11-27  Last modified: 2009-10-23
          
+
          View all other issues in [unique.ptr.single.modifiers].
          
+
          View all issues with NAD Future status.
          
+
          Discussion:
          
+
          
+If we are supporting stateful deleters, we need an overload for
+reset that
+takes a deleter as well.
+
          
+
+
          void reset( pointer p, deleter_type d);
+
          
+
+
          
+We probably need two overloads to support move-only deleters, and
+this
+sounds uncomfortably like the two constructors I have been ignoring
+for
+now...
+
          
+
+
          [
+Batavia (2009-05):
+]
          
+
+
          
+
          
+Howard comments that we have the functionality via move-assigment.
+
          
+
          
+Move to Open.
+
          
+
          
+
+
          [
+2009-10 Santa Cruz:
+]
          
+
+
+
          
+Mark as NAD Future.
+
          
+
+
+
+
          Proposed resolution:
          
+
          
+
          
+
+
+
+
+
+
          
+
          935. clock error handling needs to be specified
          
+
          Section: 20.9.5 [time.clock] Status: NAD Future
+ Submitter: Beman Dawes Opened: 2008-11-24  Last modified: 2009-10-23
          
+
          View all issues with NAD Future status.
          
+
          Discussion:
          
+
          
+Each of the three clocks specified in Clocks 20.9.5 [time.clock]
+provides the member function:
+
          
+
+
          static time_point now();
+
          
+
+
          
+The semantics specified by Clock requirements 20.9.1 [time.clock.req]
+make no mention of error handling. Thus the function may throw bad_alloc
+or an implementation-defined exception (17.6.4.11 [res.on.exception.handling]
+paragraph 4).
+
          
+
+
          
+Some implementations of these functions on POSIX, Windows, and
+presumably on other operating systems, may fail in ways only detectable
+at runtime. Some failures on Windows are due to supporting chipset
+errata and can even occur after successful calls to a clock's now()
+function.
+
          
+
+
          
+These functions are used in cases where exceptions are not appropriate
+or where the specifics of the exception or cause of error need to be
+available to the user. See
+N2828,
+Library Support for hybrid error
+handling (Rev 1), for more specific discussion of use cases. Thus some change in
+the interface of now is required.
+
          
+
+
          
+The proposed resolution has been implemented in the Boost version of the
+chrono library. No problems were encountered.
+
          
+
+
          [
+Batavia (2009-05):
+]
          
+
+
          
+
          
+We recommend this issue be deferred until the next Committee Draft
+has been issued and the prerequisite paper has been accepted.
+
          
+
          
+Move to Open.
+
          
+
          
+
+
          [
+2009-10 Santa Cruz:
+]
          
+
+
+
          
+Mark as NAD future. Too late to make this change without having already
+accepted the hybrid error handling proposal.
+
          
+
+
+
+
          Proposed resolution:
          
+
          
+Accept the proposed wording of
+N2828,
+Library Support for hybrid error handling (Rev 1).
+
          
+
+
          
+Change Clock requirements 20.9.1 [time.clock.req] as indicated:
+
          
+
+
          
+
          
+-2- In Table 55 C1 and C2 denote clock types. t1 and
+t2 are values returned by C1::now() where the call 
+returning t1 happens before (1.10) the call returning t2 and
+both of these calls happen before C1::time_point::max().
+ec denotes an object of type error_code 
+(19.5.2.1 [syserr.errcode.overview]).
+
          
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
          Table 55 -- Clock requirements
          ExpressionReturn typeOperational semantics
          .........
          C1::now()C1::time_pointReturns a time_point object representing the current point in time.
+
          C1::now(ec)C1::time_pointReturns a time_point object representing the current point in time.
+
          
+
          
+
+
          
+Change Class system_clock 20.9.5.1 [time.clock.system] as indicated:
+
          
+
+
          static time_point now(error_code& ec=throws());
+
          
+
+
          
+Change Class monotonic_clock 20.9.5.2 [time.clock.monotonic] as indicated:
+
          
+
+
          static time_point now(error_code& ec=throws());
+
          
+
+
          
+Change Class high_resolution_clock 20.9.5.3 [time.clock.hires] as indicated:
+
          
+
+
          static time_point now(error_code& ec=throws());
+
          
+
+
+
+
+
+
+
          
+
          936. Mutex type overspecified
          
+
          Section: 30.4.1 [thread.mutex.requirements] Status: NAD Future
+ Submitter: Pete Becker Opened: 2008-12-05  Last modified: 2009-10-23
          
+
          View other active issues in [thread.mutex.requirements].
          
+
          View all other issues in [thread.mutex.requirements].
          
+
          View all issues with NAD Future status.
          
+
          Duplicate of: 961
          
+
          Discussion:
          
+
+
+
+
          
+30.4.1 [thread.mutex.requirements] describes the requirements for a type to be
+a "Mutex type". A Mutex type can be used as the template argument for
+the Lock type that's passed to condition_variable_any::wait (although
+Lock seems like the wrong name here, since Lock is given a different
+formal meaning in 30.4.3 [thread.lock]) and, although the WD doesn't quite say
+so, as the template argument for lock_guard and unique_lock.
+
          
+
+
          
+The requirements for a Mutex type include:
+
          
+
+
            
+
          • 
+m.lock() shall be well-formed and have [described] semantics, including a return type of void.
+
            • 
+
          • 
+m.try_lock() shall be well-formed and have [described] semantics, including a return type of bool.
+
            • 
+
          • 
+m.unlock() shall be well-formed and have [described] semantics, including a return type of void.
+
            • 
+
          
+
+
          
+Also, a Mutex type "shall not be copyable nor movable".
+
          
+
+
          
+The latter requirement seems completely irrelevant, and the three
+requirements on return types are tighter than they need to be. For
+example, there's no reason that lock_guard can't be instantiated with a
+type that's copyable. The rule is, in fact, that lock_guard, etc. won't
+try to copy objects of that type. That's a constraint on locks, not on
+mutexes. Similarly, the requirements for void return types are
+unnecessary; the rule is, in fact, that lock_guard, etc. won't use any
+returned value. And with the return type of bool, the requirement should
+be that the return type is convertible to bool.
+
          
+
+
          [
+Summit:
+]
          
+
+
+
          
+
          
+Move to open. Related to conceptualization and should probably be tackled as part of that.
+
          
+
            
+
          • 
+The intention is not only to place a constraint on what types such as
+lock_guard may do with mutex types, but on what any code, including user
+code, may do with mutex types. Thus the constraints as they are apply to
+the mutex types themselves, not the current users of mutex types in the
+standard.
+
            • 
+
          • 
+This is a low priority issue; the wording as it is may be overly
+restrictive but this may not be a real issue.
+
            • 
+
          
+
          
+
+
          [
+Post Summit Anthony adds:
+]
          
+
+
+
          
+
          
+Section 30.4.1 [thread.mutex.requirements] conflates the
+requirements on a generic Mutex type (including user-supplied mutexes)
+with the requirements placed on the standard-supplied mutex types in an
+attempt to group everything together and save space.
+
          
+
          
+When applying concepts to chapter 30, I suggest that the concepts
+Lockable and TimedLockable embody the requirements for
+*use* of a mutex type as required by
+unique_lock/lock_guard/condition_variable_any. These should be
+relaxed as Pete describes in the issue. The existing words in 30.4.1 [thread.mutex.requirements] are requirements on all of
+std::mutex, std::timed_mutex,
+std::recursive_mutex and std::recursive_timed_mutex,
+and should be rephrased as such.
+
          
+
          
+
+
+
+
          Proposed resolution:
          
+
          
+
          
+
+
+
+
+
 
          
 
          937. Atomics for standard typedef types
          
 
          Section: 29 [atomics] Status: NAD Editorial
  Submitter: Clark Nelson Opened: 2008-12-05  Last modified: 2009-05-23
          
-
          View other active issues in [atomics].
          
 
          View all other issues in [atomics].
          
 
          View all issues with NAD Editorial status.
          
 
          Discussion:
          
@@ -23289,10 +28179,9 @@ A proposed resolution is provided by the paper on this subject,
 
          942. Atomics synopsis typo
          
 
          Section: 29 [atomics] Status: Dup
  Submitter: Holger Grund Opened: 2008-12-19  Last modified: 2009-03-22
          
-
          View other active issues in [atomics].
          
 
          View all other issues in [atomics].
          
 
          View all issues with Dup status.
          
-
          Duplicate of: 880
          
+
          Duplicate of: 880
          
 
          Discussion:
          
 
 
@@ -23321,7 +28210,7 @@ should be
 
          
 
 
          
-Note, that this is not covered by 880 "Missing atomic exchange parameter",
+Note, that this is not covered by 880 "Missing atomic exchange parameter",
 which only talks about the atomic_bool.
 
          
 
          
@@ -23341,6 +28230,89 @@ Change the synopsis in 29 [atomics]/2:
 
 
 
+
          
+
          944. atomic<bool> derive from atomic_bool?
          
+
          Section: 29.5.3 [atomics.types.generic] Status: NAD Editorial
+ Submitter: Holger Grund Opened: 2008-12-19  Last modified: 2009-10-26
          
+
          View all other issues in [atomics.types.generic].
          
+
          View all issues with NAD Editorial status.
          
+
          Discussion:
          
+
          
+I think it's fairly obvious that atomic<bool> is supposed to be derived
+from atomic_bool (and otherwise follow the atomic<integral> interface),
+though I think the current wording doesn't support this. I raised this
+point along with atomic<floating-point> privately with Herb and I seem
+to recall it came up in the resulting discussion on this list. However,
+I don't see anything on the current libs issue list mentioning this
+problem.
+
          
+
+
          
+29.5.3 [atomics.types.generic]/3 reads
+
          
+
+
          
+There are full specializations over the integral types on the atomic
+class template. For each integral type integral in the second column of
+table 121 or table 122, the specialization atomic<integral> shall be
+publicly derived from the corresponding atomic integral type in the
+first column of the table. These specializations shall have trivial
+default constructors and trivial destructors.
+
          
+
+
          
+Table 121 does not include (atomic_bool, bool),
+so that this should probably be mentioned explicitly in the quoted paragraph.
+
          
+
+
          [
+Summit:
+]
          
+
+
+
          
+Move to open. Lawrence will draft a proposed resolution. Also, ask
+Howard to fix the title.
+
          
+
+
          [
+Post Summit Anthony provided proposed wording.
+]
          
+
+
+
          [
+2009-10 Santa Cruz:
+]
          
+
+
+
          
+NAD Editorial.  Solved by
+N2992.
+
          
+
+
+
+
          Proposed resolution:
          
+
          
+Replace paragraph 3 in 29.5.3 [atomics.types.generic] with
+
          
+
+
          
+-3- There are full specializations over the integral types on the atomic
+class template. For each integral type integral in the second column of
+table 121 or table 122, the specialization atomic<integral> shall be
+publicly derived from the corresponding atomic integral type in the first
+column of the table.
+In addition, the specialization atomic<bool>
+shall be publicly derived from atomic_bool.
+These specializations shall have trivial default
+constructors and trivial destructors.
+
          
+
+
+
+
+
 
          
 
          945. system_clock::rep not specified
          
 
          Section: 20.9.5.1 [time.clock.system] Status: NAD Editorial
@@ -23478,6 +28450,123 @@ Move to NAD.
 
 
 
+
          
+
          947. duration arithmetic: contradictory requirements
          
+
          Section: 20.9.3.5 [time.duration.nonmember] Status: NAD Editorial
+ Submitter: Pete Becker Opened: 2008-12-20  Last modified: 2009-10-26
          
+
          View all other issues in [time.duration.nonmember].
          
+
          View all issues with NAD Editorial status.
          
+
          Discussion:
          
+
          
+In 20.9.3.5 [time.duration.nonmember], paragraph 8 says that calling
+dur / rep
+when rep is an instantiation of duration requires a diagnostic.
+That's followed by an operator/ that takes two durations.
+So dur1 / dur2 is legal under the second version,
+but requires a diagnostic under the first.
+
          
+
+
          [
+Howard adds:
+]
          
+
+
+
          
+Please see the thread starting with c++std-lib-22980 for more information.
+
          
+
+
          [
+Batavia (2009-05):
+]
          
+
+
          
+Move to Open, pending proposed wording (and preferably an implementation).
+
          
+
+
          [
+2009-07-27 Howard adds:
+]
          
+
+
+
          
+
          
+I've addressed this issue under the proposed wording for 1177 which
+cleans up several places under 20.9.3 [time.duration] which used the
+phrase "diagnostic required".
+
          
+
          
+For clarity's sake, here is an example implementation of the constrained operator/:
+
          
+
+
          template <class _Duration, class _Rep, bool = __is_duration<_Rep>::value>
+struct __duration_divide_result
+{
+};
+
+template <class _Duration, class _Rep2,
+    bool = is_convertible<_Rep2,
+                          typename common_type<typename _Duration::rep, _Rep2>::type>::value>
+struct __duration_divide_imp
+{
+};
+
+template <class _Rep1, class _Period, class _Rep2>
+struct __duration_divide_imp<duration<_Rep1, _Period>, _Rep2, true>
+{
+    typedef duration<typename common_type<_Rep1, _Rep2>::type, _Period> type;
+};
+
+template <class _Rep1, class _Period, class _Rep2>
+struct __duration_divide_result<duration<_Rep1, _Period>, _Rep2, false>
+    : __duration_divide_imp<duration<_Rep1, _Period>, _Rep2>
+{
+};
+
+template <class _Rep1, class _Period, class _Rep2>
+inline
+typename __duration_divide_result<duration<_Rep1, _Period>, _Rep2>::type
+operator/(const duration<_Rep1, _Period>& __d, const _Rep2& __s)
+{
+    typedef typename common_type<_Rep1, _Rep2>::type _Cr;
+    duration<_Cr, _Period> __r = __d;
+    __r /= static_cast<_Cr>(__s);
+    return __r;
+}
+
          
+
+
          
+__duration_divide_result is basically a custom-built enable_if
+that will contain type only if Rep2 is not a duration
+and if Rep2 is implicitly convertible to
+common_type<typename Duration::rep, Rep2>::type. __is_duration
+is simply a private trait that answers false, but is specialized for
+duration to answer true.
+
          
+
+
          
+The constrained operator% works identically.
+
          
+
          
+
+
          [
+2009-10 Santa Cruz:
+]
          
+
+
+
          
+Mark NAD Editorial, fixed by 1177.
+
          
+
+
+
+
          Proposed resolution:
          
+
          
+
          
+
+
+
+
+
 
          
 
          952. Various threading bugs #2
          
 
          Section: 20.9.3.7 [time.duration.cast] Status: NAD Editorial
@@ -23532,9 +28621,468 @@ Move to NAD Editorial.
 
 
 
+
          
+
          955. Various threading bugs #5
          
+
          Section: 20.9.1 [time.clock.req] Status: NAD
+ Submitter: Pete Becker Opened: 2009-01-07  Last modified: 2009-10-26
          
+
          View other active issues in [time.clock.req].
          
+
          View all other issues in [time.clock.req].
          
+
          View all issues with NAD status.
          
+
          Discussion:
          
+
          
+20.9.1 [time.clock.req] requires that a clock type have a member
+typedef named time_point that names an instantiation of the
+template time_point, and a member named duration that
+names an instantiation of the template duration. This mixing of
+levels is confusing. The typedef names should be different from the
+template names.
+
          
+
+
          [
+Post Summit, Anthony provided proposed wording.
+]
          
+
+
+
          [
+2009-05-04 Howard adds:
+]
          
+
+
+
          
+
          
+The reason that the typedef names were given the same name as the class templates
+was so that clients would not have to stop and think about whether they were
+using the clock's native time_point / duration or the class
+template directly.  In this case, one person's confusion is another person's
+encapsulation.  The detail that sometimes one is referring to the clock's
+native types, and sometimes one is referring to an independent type is
+purposefully "hidden" because it is supposed to be an unimportant
+detail.  It can be confusing to have to remember when to type duration
+and when to type duration_type, and there is no need to require the
+client to remember something like that.
+
          
+
+
          
+For example, here is code that I once wrote in testing out the usability of
+this facility:
+
          
+
+
          template <class Clock, class Duration>
+void do_until(const std::chrono::time_point<Clock, Duration>& t)
+{
+    typename Clock::time_point now = Clock::now();
+    if (t > now)
+    {
+        typedef typename std::common_type
+        <
+            Duration,
+            typename std::chrono::system_clock::duration
+        >::type CD;
+        typedef std::chrono::duration<double, std::nano> ID;
+
+        CD d = t - now;
+        ID us = duration_cast<ID>(d);
+        if (us < d)
+            ++us;
+        ...
+    }
+}
+
          
+
+
          
+I see no rationale to require the client to append _type to some
+of those declarations.  It seems overly burdensome on the author of do_until:
+
          
+
+
          template <class Clock, class Duration>
+void do_until(const std::chrono::time_point<Clock, Duration>& t)
+{
+    typename Clock::time_point_type now = Clock::now();
+    if (t > now)
+    {
+        typedef typename std::common_type
+        <
+            Duration,
+            typename std::chrono::system_clock::duration_type
+        >::type CD;
+        typedef std::chrono::duration<double, std::nano> ID;
+
+        CD d = t - now;
+        ID us = duration_cast<ID>(d);
+        if (us < d)
+            ++us;
+        ...
+    }
+}
+
          
+
+
          
+Additionally I'm fairly certain that this suggestion hasn't been implemented.
+If it had, it would have been discovered that it is incomplete.  time_point
+also has a nested type (purposefully) named duration.
+
          
+
          
+That is, the current proposed wording would put the WP into an inconsistent state.
+
          
+
          
+In contrast,
+the current WP has been implemented and I've received very favorable feedback
+from people using this interface in real-world code.
+
          
+
+
          
+
+
          [
+Batavia (2009-05):
+]
          
+
+
          
+
          
+Bill agrees that distinct names should be used for distinct kinds of entities.
+
          
+
          
+Walter would prefer not to suffix type names,
+especially for such well-understood terms as "duration".
+
          
+
          
+Howard reminds us that the proposed resolution is incomplete, per his comment
+in the issue.
+
          
+
          
+Move to Open.
+
          
+
          
+
+
          [
+2009-06-07 Howard adds:
+]
          
+
+
+
          
+
          
+Not meaning to be argumentative, but we have a decade of positive experience
+with the precedent of using the same name for the nested type as an external
+class representing an identical concept.
+
          
+
+
          template<class Category, class T, class Distance = ptrdiff_t,
+         class Pointer = T*, class Reference = T&>
+struct iterator
+{
+    ...
+};
+
+template <BidirectionalIterator Iter>
+class reverse_iterator
+{
+    ...
+};
+
+template <ValueType T, Allocator Alloc = allocator<T> >
+    requires NothrowDestructible<T>
+class list
+{
+public:
+    typedef implementation-defined     iterator;
+    ...
+    typedef reverse_iterator<iterator> reverse_iterator;
+    ...
+};
+
          
+
+
          
+I am aware of zero complaints regarding the use of iterator
+and reverse_iterator as nested types of the containers despite these
+names also having related meaning at namespace std scope.
+
          
+
+
          
+Would we really be doing programmers a favor by renaming these nested types?
+
          
+
+
          template <ValueType T, Allocator Alloc = allocator<T> >
+    requires NothrowDestructible<T>
+class list
+{
+public:
+    typedef implementation-defined     iterator_type;
+    ...
+    typedef reverse_iterator<iterator> reverse_iterator_type;
+    ...
+};
+
          
+
+
          
+I submit that such design contributes to needless verbosity which ends up
+reducing readability.
+
          
+
          
+
+
          [
+2009-10 Santa Cruz:
+]
          
+
+
+
          
+Mark as NAD.  No concensus for changing the WP.
+
          
+
+
+
+
          Proposed resolution:
          
+
          
+Change 20.9 [time]:
+
          
+
+
          ...
+template <class Clock, class Duration = typename Clock::duration_type> class time_point;
+...
+
          
+
+
          
+Change 20.9.1 [time.clock.req]:
+
          
+
+
          
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
          Table 45 -- Clock requirements
          ExpressionReturn typeOperational semantics
          .........
          C1::duration_typechrono::duration<C1::rep, C1::period>The native duration type of the clock.
          C1::time_point_typechrono::time_point<C1> or chrono::time_point<C2, C1::duration_type<The native time_point type of the clock.   Different clocks may  share a time_point_type
+definition if it is valid to 
+compare their time_point_types by 
+comparing their respective 
+duration_types. C1 and C2 shall 
+refer to the same epoch.
          .........
          C1::now()C1::time_point_typeReturns a time_point_type object 
+representing the current point 
+in time.
+
          
+
          
+
+
          
+Change 20.9.5.1 [time.clock.system]:
+
          
+
+
          
+
          
+-1- Objects of class system_clock represent wall clock time from the system-wide realtime clock.
+
          
+
+
          class system_clock { 
+public: 
+  typedef see below rep; 
+  typedef ratio<unspecified, unspecified> period; 
+  typedef chrono::duration<rep, period> duration_type; 
+  typedef chrono::time_point<system_clock> time_point_type; 
+  static const bool is_monotonic = unspecified ; 
+
+  static time_point_type now(); 
+
+  // Map to C API 
+  static time_t to_time_t (const time_point_type& t); 
+  static time_point_type from_time_t(time_t t); 
+};
+
          
+
+
          
+-2- system_clock::duration_type::min() < system_clock::duration_type::zero() shall be true.
+
          
+
+
          time_t to_time_t(const time_point_type& t);
+
          
+
+
          
+-3- Returns: A time_t object that represents the same
+point in time as t when both values are truncated to the
+coarser of the precisions of time_t and time_point_type.
+
          
+
+
          time_point_type from_time_t(time_t t);
+
          
+
+
          
+-4- Returns: A time_point_type object that represents the same point
+in time as t when both values are truncated to the coarser of the
+precisions of time_t and time_point_type.
+
          
+
          
+
+
          
+Change 20.9.5.2 [time.clock.monotonic]:
+
          
+
+
          class monotonic_clock { 
+public: 
+  typedef unspecified                                rep; 
+  typedef ratio<unspecified , unspecified>           period; 
+  typedef chrono::duration<rep, period>              duration_type; 
+  typedef chrono::time_point<unspecified , duration_type> time_point_type; 
+  static const bool is_monotonic =                   true; 
+
+  static time_point_type now();
+};
+
          
+
+
          
+Change 20.9.5.3 [time.clock.hires]:
+
          
+
+
          class high_resolution_clock { 
+public: 
+  typedef unspecified                                rep; 
+  typedef ratio<unspecified , unspecified>           period; 
+  typedef chrono::duration<rep, period>              duration_type; 
+  typedef chrono::time_point<unspecified , duration_type> time_point_type; 
+  static const bool is_monotonic =                   true; 
+
+  static time_point_type now();
+};
+
          
+
+
+
+
+
+
+
          
+
          958. Various threading bugs #8
          
+
          Section: 30.5.1 [thread.condition.condvar] Status: NAD Editorial
+ Submitter: Pete Becker Opened: 2009-01-07  Last modified: 2009-10-23
          
+
          View other active issues in [thread.condition.condvar].
          
+
          View all other issues in [thread.condition.condvar].
          
+
          View all issues with NAD Editorial status.
          
+
          Discussion:
          
+
          
+30.5.1 [thread.condition.condvar]: the specification for wait_for
+with no predicate has an effects clause that says it calls wait_until,
+and a returns clause that sets out in words how to determine the return
+value. Is this description of the return value subtly different from the
+description of the value returned by wait_until? Or should the effects
+clause and the returns clause be merged?
+
          
+
+
          [
+Summit:
+]
          
+
+
+
          
+Move to open. Associate with LWG 859 and any other monotonic-clock
+related issues.
+
          
+
+
          [
+2009-08-01 Howard adds:
+]
          
+
+
+
          
+I believe that 859 (currently Ready) addresses this issue, and
+that this issue should be marked NAD, solved by 859 (assuming
+it moves to WP).
+
          
+
+
          [
+2009-10 Santa Cruz:
+]
          
+
+
+
          
+Mark as NAD Editorial, solved by resolution of Issue 859.
+
          
+
+
+
+
          Proposed resolution:
          
+
          
+
          
+
+
+
+
+
+
          
+
          961. Various threading bugs #11
          
+
          Section: 30.4.1 [thread.mutex.requirements] Status: NAD Future
+ Submitter: Pete Becker Opened: 2009-01-07  Last modified: 2009-10-26
          
+
          View other active issues in [thread.mutex.requirements].
          
+
          View all other issues in [thread.mutex.requirements].
          
+
          View all issues with NAD Future status.
          
+
          Duplicate of: 936
          
+
          Discussion:
          
+
          
+30.4.1 [thread.mutex.requirements] describes required member
+functions of mutex types, and requires that they throw exceptions under
+certain circumstances. This is overspecified. User-defined types can
+abort on such errors without affecting the operation of templates
+supplied by standard-library.
+
          
+
+
          [
+Summit:
+]
          
+
+
          
+Move to open. Related to conceptualization and should probably be
+tackled as part of that.
+
          
+
+
          [
+2009-10 Santa Cruz:
+]
          
+
+
+
          
+
          
+Would be OK to leave it as is for time constraints, could loosen later.
+
          
+
+
          
+Mark as NAD Future.
+
          
+
          
+
+
+
+
          Proposed resolution:
          
+
          
+
          
+
+
+
+
+
 
          
 
          969. What happened to Library Issue 475?
          
-
          Section: 25.3.4 [alg.foreach] Status: NAD Editorial
+
          Section: 25.2.4 [alg.foreach] Status: NAD Editorial
  Submitter: Stephan T. Lavavej Opened: 2009-01-12  Last modified: 2009-07-13
          
 
          View all other issues in [alg.foreach].
          
 
          View all issues with NAD Editorial status.
          
@@ -23544,7 +29092,7 @@ Library Issue N2723
 was removed in
 N2798
-(25.3.4 [alg.foreach] in both drafts).
+(25.2.4 [alg.foreach] in both drafts).
 
          
 
 
          [
@@ -23565,6 +29113,119 @@ Restore the non-normative note. It might need to be expressed in terms of concep
 
 
 
+
          
+
          971. Spurious diagnostic conversion function
          
+
          Section: 19.5.2.5 [syserr.errcode.nonmembers] Status: NAD
+ Submitter: Beman Dawes Opened: 2009-01-19  Last modified: 2009-10-20
          
+
          View all issues with NAD status.
          
+
          Discussion:
          
+
          
+Anthony Williams raised the question in c++std-lib-22987 "why is there
+std::make_error_code(std::errc)? What purpose does this serve?"
+
          
+
          
+The function make_error_code(errc e) is not required, since
+make_error_condition(errc e) is the function that is needed for errc
+conversions. make_error_code(errc e) appears to be a holdover from my
+initial confusion over the distinction between POSIX and operating
+systems that conform to the POSIX spec.
+
          
+
+
          [
+Post Summit:
+]
          
+
+
+
          
+Recommend Review.
+
          
+
+
          [
+Batavia (2009-05):
+]
          
+
+
          
+The designer of the facility (Christopher Kohlhoff)
+strongly disagrees that there is an issue here,
+and especially disagrees with the proposed resolution.
+Bill would prefer to be conservative and not apply this proposed resolution.
+Move to Open, and recommend strong consideration for NAD status.
+
          
+
+
          [
+2009-05-21 Beman adds:
+]
          
+
+
+
          
+My mistake. Christopher and Bill are correct and the issue should be
+NAD. The function is needed by users.
+
          
+
+
          [
+2009-07-21 Christopher Kohlhoff adds rationale for make_error_code:
+]
          
+
+
+
          
+
          
+Users (and indeed library implementers) may need to use the
+errc codes in portable code. For example:
+
          
+
+
          void do_foo(error_code& ec)
+{
+#if defined(_WIN32)
+  // Windows implementation ...
+#elif defined(linux)
+  // Linux implementation ...
+#else
+  // do_foo not supported on this platform
+  ec = make_error_code(errc::not_supported);
+#endif
+}
+
          
+
          
+
+
          [
+2009 Santa Cruz:
+]
          
+
+
+
          
+Moved to NAD.
+
          
+
+
+
+
          Proposed resolution:
          
+
          
+Change System error support 19.5 [syserr], Header <system_error>
+synopsis, as indicated:
+
          
+
+
          error_code make_error_code(errc e);
+error_condition make_error_condition(errc e);
+
          
+
+
          
+Delete from Class error_code non-member functions
+19.5.2.5 [syserr.errcode.nonmembers]:
+
          
+
+
          error_code make_error_code(errc e);
+
          
+
          
+Returns: error_code(static_cast<int>(e),
+generic_category).
+
          
+
          
+
+
+
+
+
+
 
          
 
          972. The term "Assignable" undefined but still in use
          
 
          Section: 17 [library] Status: NAD Editorial
@@ -23616,19 +29277,19 @@ Change Class template reference_wrapper 20.7.5 [refwrap]:
 reference_wrapper<T> is a CopyConstructible and CopyAssignable wrapper around a reference to an object of type T.
 
          4. 
 
          
-Change Placeholders 20.7.12.1.4 [func.bind.place]:
+Change Placeholders 20.7.11.1.4 [func.bind.place]:
 
          
 
          
 It is implementation defined whether placeholder types are CopyAssignable. CopyAssignable placeholders' copy assignment operators shall not throw exceptions.
 
          
 
          
-Change Class template shared_ptr 20.8.10.2 [util.smartptr.shared]:
+Change Class template shared_ptr 20.8.15.2 [util.smartptr.shared]:
 
          
 
          
 Specializations of shared_ptr shall be CopyConstructible, CopyAssignable, and LessThanComparable...
 
          
 
          
-Change Class template weak_ptr 20.8.10.3 [util.smartptr.weak]:
+Change Class template weak_ptr 20.8.15.3 [util.smartptr.weak]:
 
          
 
          
 Specializations of weak_ptr shall be CopyConstructible, CopyAssignable, and LessThanComparable...
@@ -23649,7 +29310,7 @@ In addition to the requirements set forth below, instances of
 
 
          
 Note: The proposed resolution of this issue does not deal with the
-instance of the term "Assignable" in D.9.1 [auto.ptr], as this is dealt
+instance of the term "Assignable" in D.10.1 [auto.ptr], as this is dealt
 with more specifically by LWG 973, "auto_ptr characteristics", submitted
 by Maarten Hilferink.
 
          
@@ -23661,13 +29322,13 @@ by Maarten Hilferink.
 
 
          
 
          973. auto_ptr characteristics
          
-
          Section: D.9.1 [auto.ptr] Status: NAD Editorial
+
          Section: D.10.1 [auto.ptr] Status: NAD Editorial
  Submitter: Maarten Hilferink Opened: 2009-01-21  Last modified: 2009-07-13
          
 
          View all other issues in [auto.ptr].
          
 
          View all issues with NAD Editorial status.
          
 
          Discussion:
          
 
          
-I think that the Note of D.9.1 [auto.ptr], paragraph 3 needs a rewrite 
+I think that the Note of D.10.1 [auto.ptr], paragraph 3 needs a rewrite 
 since "Assignable" is no longer defined as a concept. 
 The relationship of auto_ptr with the new CopyAssignable, MoveAssignable,
  and MoveConstructible concepts should be clarified.
@@ -23687,7 +29348,7 @@ Move to NAD Editorial.
 
 
          Proposed resolution:
          
 
          
-Change D.9.1 [auto.ptr], paragraph 3:
+Change D.10.1 [auto.ptr], paragraph 3:
 
          
 
 
          
@@ -23717,14 +29378,412 @@ requirements, but do not meet the CopyConstructible and
 
 
 
+
          
+
          976. Class template std::stack should be movable
          
+
          Section: 23.3.5.3.1 [stack.defn] Status: NAD Editorial
+ Submitter: Daniel Krügler Opened: 2009-02-01  Last modified: 2009-10-20
          
+
          View all issues with NAD Editorial status.
          
+
          Discussion:
          
+
          
+The synopsis given in 23.3.5.3.1 [stack.defn] does not show up
+
          
+
+
          requires MoveConstructible<Cont> stack(stack&&);
+requires MoveAssignable<Cont> stack& operator=(stack&&);
+
          
+
+
          
+although the other container adaptors do provide corresponding
+members.
+
          
+
+
          [
+Batavia (2009-05):
+]
          
+
+
          
+
          
+We agree with the proposed resolution.
+
          
+
          
+Move to Tentatively Ready.
+
          
+
          
+
+
          [
+2009-07 Frankfurt
+]
          
+
+
+
          
+Moved from Tentatively Ready to Open only because the wording needs to be
+tweaked for concepts removal.
+
          
+
+
          [
+2009-08-18 Daniel updates the wording and Howard sets to Review.
+]
          
+
+
+
          [
+2009-08-23 Howard adds:
+]
          
+
+
+
          
+1194 also adds these move members using an editorially different
+style.
+
          
+
+
          [
+2009-10 Santa Cruz:
+]
          
+
+
+
          
+Mark NAD Editorial, solved by issue 1194.
+
          
+
+
+
+
          Proposed resolution:
          
+
          
+In the class stack synopsis of 23.3.5.3.1 [stack.defn] insert:
+
          
+
+
          template <class T, class Container = deque<T> >
+class stack {
+  [..]
+  explicit stack(const Container&);
+  explicit stack(Container&& = Container());
+  stack(stack&& s) : c(std::move(s.c)) {}
+  stack& operator=(stack&& s) { c = std::move(s.c); return *this; }
+  [..]
+};
+
          
+
+
+
+
+
+
+
+
+
          
+
          977. insert iterators inefficient for expensive to move types
          
+
          Section: 24.5.2 [insert.iterators] Status: NAD
+ Submitter: Howard Hinnant Opened: 2009-02-02  Last modified: 2009-10-26
          
+
          View all other issues in [insert.iterators].
          
+
          View all issues with NAD status.
          
+
          Discussion:
          
+
          
+The new concepts for the insert iterators mandate an extra copy when
+inserting an lvalue:
+
          
+
+
          requires CopyConstructible<Cont::value_type>
+  back_insert_iterator<Cont>& 
+  operator=(const Cont::value_type& value);
+
          
+
          
+-1- Effects: push_back(*container, Cont::value_type(value));
+
          
+
          
+
+
          
+The reason is to convert value into an rvalue because the current
+BackInsertionContainer concept only handles push_back-ing
+rvalues:
+
          
+
+
          concept BackInsertionContainer<typename C> : Container<C> { 
+  void push_back(C&, value_type&&); 
+}
+
          
+
+
          
+Without the conversion of value to an rvalue, the assignment operator
+fails to concept check.
+
          
+
+
          
+A solution is to modify the BackInsertionContainer concept so that
+the client can pass in the parameter type for push_back similar to
+what is already done for the OutputIterator concept:
+
          
+
+
          concept BackInsertionContainer<typename C, typename Value = C::value_type&&>
+  : Container<C> { 
+     void push_back(C&, Value); 
+}
+
          
+
+
          
+This allows the assignment operator to be adjusted appropriately:
+
          
+
+
          requires BackInsertionContainer<Cont, Cont::value_type const&> &&
+         CopyConstructible<Cont::value_type>
+  back_insert_iterator<Cont>& 
+  operator=(const Cont::value_type& value);
+
          
+
          
+-1- Effects: push_back(*container, value);
+
          
+
          
+
+
          [
+We may want to propagate this fix to other concepts such as StackLikeContainer.
+]
          
+
+
+
          [
+Solution and wording collaborated on by Doug and Howard.
+]
          
+
+
+
          [
+Batavia (2009-05):
+]
          
+
+
          
+
          
+Howard notes that "these operations behaved efficiently until concepts were added."
+
          
+
          
+Alisdair is uncertain that the proposed resolution is syntactically correct.
+
          
+
          
+Move to Open, and recommend the issue be deferred until after the next
+Committee Draft is issued.
+
          
+
          
+
+
          [
+2009-10 Santa Cruz:
+]
          
+
+
+
          
+NAD, solved by the removal of concepts.
+
          
+
+
+
+
          Proposed resolution:
          
+
          
+Change  [container.concepts.free]:
+
          
+
+
          
+
          concept FrontInsertionContainer<typename C, typename Value = C::value_type&&>
+    : Container<C> { 
+  void push_front(C&, value_type&& Value); 
+
+  axiom FrontInsertion(C c, value_type Value x) { 
+    x == (push_front(c, x), front(c)); 
+  } 
+}
+
          
+
+
          ...
          
+
+
          concept BackInsertionContainer<typename C, typename Value = C::value_type&&>
+    : Container<C> { 
+  void push_back(C&, value_type&& Value); 
+}
+
          
+
+
          ...
          
+
+
          concept InsertionContainer<typename C, typename Value = C::value_type&&>
+    : Container<C> { 
+  iterator insert(C&, const_iterator, value_type&& Value); 
+
+  axiom Insertion(C c, const_iterator position, value_type Value v) { 
+    v == *insert(c, position, v); 
+  } 
+}
+
          
+
+
          
+
+
          
+Change  [container.concepts.member]:
+
          
+
+
          
+
          auto concept MemberFrontInsertionContainer<typename C, typename Value = C::value_type&&>
+    : MemberContainer<C> { 
+  void C::push_front(value_type&& Value); 
+
+  axiom MemberFrontInsertion(C c, value_type Value x) { 
+    x == (c.push_front(x), c.front()); 
+  } 
+}
+
          
+
+
          ...
          
+
+
          auto concept MemberBackInsertionContainer<typename C, typename Value = C::value_type&&>
+    : MemberContainer<C> { 
+  void C::push_back(value_type&& Value); 
+}
+
          
+
+
          ...
          
+
+
          auto concept MemberInsertionContainer<typename C, typename Value = C::value_type&&>
+    : MemberContainer<C> { 
+  iterator C::insert(const_iterator, value_type&& Value); 
+
+  axiom MemberInsertion(C c, const_iterator position, value_type Value v) { 
+    v == *c.insert(position, v); 
+  } 
+}
+
          
+
          
+
+
          
+Change  [container.concepts.maps]:
+
          
+
+
          
+
          template <MemberFrontInsertionContainer C, typename Value = C::value_type&&> 
+concept_map FrontInsertionContainer<C, Value> { 
+  typedef Container<C>::value_type value_type;
+
+  void push_front(C& c, value_type&& Value v) { c.push_front(static_cast<value_type&& Value>(v)); } 
+}
+
          
+
+
          ...
          
+
+
          template <MemberBackInsertionContainer C, typename Value = C::value_type&&> 
+concept_map BackInsertionContainer<C, Value> { 
+  typedef Container<C>::value_type value_type;
+
+  void push_back(C& c, value_type&& Value v) { c.push_back(static_cast<value_type&& Value>(v)); } 
+}
+
          
+
+
          ...
          
+
+
          template <MemberInsertionContainer C, typename Value = C::value_type&&> 
+concept_map InsertionContainer<C, Value> { 
+  typedef Container<C>::value_type value_type;
+  Container<C>::iterator insert(C& c, Container<C>::const_iterator i, value_type&& Value v) 
+  { return c.insert(i, static_cast<value_type&& Value>(v)); } 
+}
+
          
+
+
          
+
+
          
+Change 24.5.2.1 [back.insert.iterator]:
+
          
+
+
          template <BackInsertionContainer Cont> 
+class back_insert_iterator {
+  ...
+  requires BackInsertionContainer<Cont, const Cont::value_type&>
+           CopyConstructible<Cont::value_type>
+    back_insert_iterator<Cont>& 
+      operator=(const Cont::value_type& value);
+  ...
+
          
+
+
          
+Change 24.5.2.2.2 [back.insert.iter.op=]:
+
          
+
+
          
+
          requires BackInsertionContainer<Cont, const Cont::value_type&>
+         CopyConstructible<Cont::value_type>
+  back_insert_iterator<Cont>& 
+    operator=(const Cont::value_type& value);
+
          
+
          
+-1- Effects: push_back(*container, Cont::value_type(value));
+
          
+
          
+
+
          
+Change 24.5.2.3 [front.insert.iterator]:
+
          
+
+
          template <FrontInsertionContainer Cont> 
+class front_insert_iterator {
+  ...
+  requires FrontInsertionContainer<Cont, const Cont::value_type&>
+           CopyConstructible<Cont::value_type>
+    front_insert_iterator<Cont>& 
+      operator=(const Cont::value_type& value);
+  ...
+
          
+
+
          
+Change 24.5.2.4.2 [front.insert.iter.op=]:
+
          
+
+
          
+
          requires FrontInsertionContainer<Cont, const Cont::value_type&>
+         CopyConstructible<Cont::value_type>
+  front_insert_iterator<Cont>& 
+    operator=(const Cont::value_type& value);
+
          
+
          
+-1- Effects: push_front(*container, Cont::value_type(value));
+
          
+
          
+
+
          
+Change 24.5.2.5 [insert.iterator]:
+
          
+
+
          template <InsertionContainer Cont> 
+class insert_iterator {
+  ...
+  requires InsertionContainer<Cont, const Cont::value_type&>
+           CopyConstructible<Cont::value_type>
+    insert_iterator<Cont>& 
+      operator=(const Cont::value_type& value);
+  ...
+
          
+
+
          
+Change 24.5.2.6.2 [insert.iter.op=]:
+
          
+
+
          
+
          requires InsertionContainer<Cont, const Cont::value_type&>
+         CopyConstructible<Cont::value_type>
+  insert_iterator<Cont>& 
+    operator=(const Cont::value_type& value);
+
          
+
          
+
          
+-1- Effects:
+
          
+
          iter = insert(*container, iter, Cont::value_type(value)); 
+++iter;
+
          
+
          
+
          
+
+
+
+
+
+
 
          
 
          979. Bad example
          
-
          Section: 24.5.2 [move.iterators] Status: NAD Editorial
+
          Section: 24.5.3 [move.iterators] Status: NAD Editorial
  Submitter: Howard Hinnant Opened: 2009-02-03  Last modified: 2009-07-13
          
 
          View all issues with NAD Editorial status.
          
 
          Discussion:
          
 
          
-24.5.2 [move.iterators] has an incorrect example:
+24.5.3 [move.iterators] has an incorrect example:
 
          
 
 
          
@@ -23761,7 +29820,7 @@ We agree with the proposed resolution. Move to NAD Editorial.
 
 
          Proposed resolution:
          
 
          
-Change 24.5.2 [move.iterators]/2:
+Change 24.5.3 [move.iterators]/2:
 
          
 
 
          
@@ -23878,13 +29937,13 @@ to detect it.
 
 
          
 
          988. Reflexivity meaningless?
          
-
          Section: 20.2.6 [concept.comparison] Status: NAD
+
          Section: X [concept.comparison] Status: NAD
  Submitter: Alisdair Meredith Opened: 2009-02-24  Last modified: 2009-07-16
          
 
          View all other issues in [concept.comparison].
          
 
          View all issues with NAD status.
          
 
          Discussion:
          
 
          
-20.2.6 [concept.comparison] p2:
+X [concept.comparison] p2:
 
          
 
          
 Due to the subtle meaning of == inside axioms, the Reflexivity axiom does
@@ -23897,7 +29956,7 @@ Original proposed resolution:
 
 
 
          
-Change the definition of Reflexivity in 20.2.6 [concept.comparison]:
+Change the definition of Reflexivity in X [concept.comparison]:
 
          
 
 
          axiom Reflexivity(T a) { (a == a) == true; }
@@ -24039,7 +30098,7 @@ nested within namespace std*.
 
          
 
 
          
-*The C standard library headers D.5 [depr.c.headers] also define
+*The C standard library headers D.6 [depr.c.headers] also define
 names within the global namespace, while the C++ headers for
 C library facilities 17.6.1.2 [headers] may also define names within
 the global namespace.
@@ -24085,7 +30144,7 @@ perfectly clear.
 
 
          
 
          1000. adjacent_find is over-constrained
          
-
          Section: 25.3.8 [alg.adjacent.find] Status: NAD Concepts
+
          Section: 25.2.8 [alg.adjacent.find] Status: NAD Concepts
  Submitter: Chris Jefferson Opened: 2009-03-09  Last modified: 2009-07-15
          
 
          View all other issues in [alg.adjacent.find].
          
 
          View all issues with NAD Concepts status.
          
@@ -24140,7 +30199,7 @@ does not appear to open up any possibility for a more optimised algorithm.
 
          Proposed resolution:
          
 
          
 Change the definition of adjacent_find in the synopsis of 25 [algorithms]
-and 25.3.8 [alg.adjacent.find] to:
+and 25.2.8 [alg.adjacent.find] to:
 
          
 
 
          template<ForwardIterator Iter> 
@@ -24354,7 +30413,7 @@ Alisdair: I'd prefer to see this closed as NAD and have this resolution
 be the subject of some other, new issue.
 
          
 
          
-Move to NAD Concepts. Howard to open a new issue (1178) in Ready state with the
+Move to NAD Concepts. Howard to open a new issue (1178) in Ready state with the
 Proposed Resolution above. Beman will write up a discussion for the new
 issue.
 
          
@@ -24678,11 +30737,168 @@ review.
 
 
 
+
          
+
          1009. InputIterator post-increment dangerous
          
+
          Section: X [iterator.iterators] Status: NAD
+ Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-10-22
          
+
          View all issues with NAD status.
          
+
          Discussion:
          
+
+
          Addresses UK 251
          
+
+
          
+The post-increment operator is dangerous for a general InputIterator.
+The multi-pass guarantees that make it meaningful are defined as part of
+the ForwardIterator refinement. Any change will affect only constrained
+templates that have not yet been written, so should not break existing
+user iterators which remain free to add these operations. This change
+will also affect the generalised OutputIterator, although there is no
+percieved need for the post-increment operator in this case either.
+
          
+
+
          [
+2009-07-28 Alisdair adds:
+]
          
+
+
+
          
+We still think the issue is relevant, but needs totally rewording in
+non-concept language.  We would like to see the issue retained as Open,
+rather than deferred as NAD Concepts.  Review status is no longer
+appropriate.
+
          
+
+
          [
+2009-10 Santa Cruz:
+]
          
+
+
+
          
+NAD.  Without concepts we do not feel that input iterator post increment
+is broken.
+
          
+
+
+
+
          Proposed resolution:
          
+
          
+Change X [iterator.iterators]:
+
          
+
+
          concept Iterator<typename X> : Semiregular<X> { 
+  MoveConstructible reference = typename X::reference; 
+  MoveConstructible postincrement_result;
+
+  requires HasDereference<postincrement_result>;
+
+  reference operator*(X&&); 
+  X& operator++(X&); 
+  postincrement_result operator++(X&, int);
+}
+
          
+
+
          ...
          
+
          postincrement_result operator++(X& r, int);
+
          
+
+
          
+-3- Effects: equivalent to { X tmp = r; ++r; return tmp; }.
+
          
+
+
          
+
+
          
+Change 24.2.1 [input.iterators]:
+
          
+
+
          
+
          concept InputIterator<typename X> : Iterator<X>, EqualityComparable<X> { 
+  ObjectType value_type = typename X::value_type; 
+  MoveConstructible pointer = typename X::pointer; 
+
+  SignedIntegralLike difference_type = typename X::difference_type; 
+
+  requires IntegralType<difference_type> 
+        && Convertible<reference, const value_type &>; 
+        && Convertible<pointer, const value_type*>; 
+
+  requires Convertible<HasDereference<postincrement_result>::result_type, const value_type&>;
+
+  pointer operator->(const X&); 
+}
+
          
+
          
+
+
          
+Change 24.2.2 [output.iterators]:
+
          
+
+
          
+
          auto concept OutputIterator<typename X, typename Value> { 
+  requires Iterator<X>; 
+
+  typename reference = Iterator<X>::reference; 
+  typename postincrement_result = Iterator<X>::postincrement_result;
+  requires SameType<reference, Iterator<X>::reference> 
+        && SameType<postincrement_result, Iterator<X>::postincrement_result>
+        && Convertible<postincrement_result, const X&>
+        && HasAssign<reference, Value> 
+        && HasAssign<HasDereference<postincrement_result>::result_type, Value>;
+}
+
          
+
          
+
+
          
+Change 24.2.3 [forward.iterators]:
+
          
+
+
          [
+See 1084 which is attempting to change this same area in a compatible
+way.
+]
          
+
+
+
          
+
          concept ForwardIterator<typename X> : InputIterator<X>, Regular<X> { 
+  requires Convertible<postincrement_result, const X&>;
+
+  MoveConstructible postincrement_result;
+  requires HasDereference<postincrement_result>
+        && Convertible<HasDereference<postincrement_result>::result_type, const value_type&>;
+
+  postincrement_result operator++(X&, int);
+
+  axiom MultiPass(X a, X b) { 
+    if (a == b) *a == *b; 
+    if (a == b) ++a == ++b; 
+  } 
+}
+
          
+
+
          
+
          -4- ...
          
+
          
+
+
          postincrement_result operator++(X& r, int);
+
          
+
+
          
+
          
+-5- Effects: equivalent to { X tmp = r; ++r; return tmp; }.
+
          
+
          
+
+
          
+
+
+
+
+
+
 
          
 
          1010. operator-= should use default in concept
          
-
          Section: 24.2.6 [random.access.iterators] Status: NAD Concepts
+
          Section: 24.2.5 [random.access.iterators] Status: NAD Concepts
  Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-07-16
          
-
          View other active issues in [random.access.iterators].
          
 
          View all other issues in [random.access.iterators].
          
 
          View all issues with NAD Concepts status.
          
 
          Discussion:
          
@@ -24710,7 +30926,7 @@ Move to Open.
 
 
          Proposed resolution:
          
 
          
-Change 24.2.6 [random.access.iterators]:
+Change 24.2.5 [random.access.iterators]:
 
          
 
 
          concept RandomAccessIterator<typename X> : BidirectionalIterator<X>, LessThanComparable<X> {
@@ -24727,7 +30943,7 @@ Change 24.2.6 [random.access.iterators]:
 
 
          
 
          1013. Response to UK 305
          
-
          Section: 25.5.7 [alg.min.max] Status: NAD Editorial
+
          Section: 25.4.7 [alg.min.max] Status: NAD Editorial
  Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-07-16
          
 
          View all other issues in [alg.min.max].
          
 
          View all issues with NAD Editorial status.
          
@@ -24781,7 +30997,7 @@ template<class T, StrictWeakOrder<auto, T> Compare>
 
          
 
 
          
-Change 25.5.7 [alg.min.max], p1, p9 and p17:
+Change 25.4.7 [alg.min.max], p1, p9 and p17:
 
          
 
 
          template<class T, StrictWeakOrder<auto, T> Compare>
@@ -24804,7 +31020,7 @@ template<class T, StrictWeakOrder<auto, T> Compare>
 
 
          
 
          1015. Response to UK 199
          
-
          Section: 20.2.1 [concept.transform] Status: NAD Concepts
+
          Section: X [concept.transform] Status: NAD Concepts
  Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-07-15
          
 
          View all other issues in [concept.transform].
          
 
          View all issues with NAD Concepts status.
          
@@ -24836,7 +31052,7 @@ The same problem is present in the words added for the
 With three subsections requiring the same constraint, I'm wondering if there
 is a better way to organise this section.
 Possible 20.2.1 -> 20.2.3 belong in the fundamental concepts clause in
-14.10.4 [concept.support]?  While they can be implemented purely as a
+ [concept.support]?  While they can be implemented purely as a
 library feature without additional compiler support, they are pretty
 fundamental and we want the same restriction on user-concept maps as is
 mandated there.
@@ -24858,7 +31074,7 @@ Move to Open pending the recommended investigation.
 
 
          Proposed resolution:
          
 
          
-Change 20.2.1 [concept.transform] p2:
+Change X [concept.transform] p2:
 
          
 
 
          
@@ -24867,7 +31083,7 @@ any concept in 20.1.1.
 
          
 
 
          
-Change 20.2.2 [concept.true] p2:
+Change  [concept.true] p2:
 
          
 
 
          
@@ -24876,7 +31092,7 @@ provide a concept map for the True concept.
 
          
 
 
          
-Change 20.2.3 [concept.classify] p2:
+Change  [concept.classify] p2:
 
          
 
 
          
@@ -24891,7 +31107,7 @@ maps for any concept in this section.
 
 
          
 
          1016. Response to JP 33
          
-
          Section: 20.2.6 [concept.comparison] Status: NAD Concepts
+
          Section: X [concept.comparison] Status: NAD Concepts
  Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-07-15
          
 
          View all other issues in [concept.comparison].
          
 
          View all issues with NAD Concepts status.
          
@@ -24939,7 +31155,7 @@ Recommend NAD.
 
 
          
 
          1017. Response to US 66
          
-
          Section: 20.2.11 [concept.regular] Status: NAD Concepts
+
          Section: X [concept.regular] Status: NAD Concepts
  Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-07-15
          
 
          View all issues with NAD Concepts status.
          
 
          Discussion:
          
@@ -24992,7 +31208,6 @@ feature.
 
          1018. Response to US 70
          
 
          Section: 20.6 [meta] Status: NAD Concepts
  Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-07-15
          
-
          View other active issues in [meta].
          
 
          View all other issues in [meta].
          
 
          View all issues with NAD Concepts status.
          
 
          Discussion:
          
@@ -25032,9 +31247,68 @@ at the next meeting.
 
 
 
+
          
+
          1020. Response to UK 204
          
+
          Section: 20.6.7 [meta.trans.other] Status: NAD
+ Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-10-23
          
+
          View all other issues in [meta.trans.other].
          
+
          View all issues with NAD status.
          
+
          Discussion:
          
+
+
          Addresses UK 204
          
+
+
          
+It is not possible to create a variant union based on a parameter pack
+expansion, e.g. to implement a classic discriminated union template. 
+
          
+
+
          Original proposed resolutuion:
          
+
+
          
+Restore aligned_union template that was removed by LWG issue 856. 
+
          
+
+
          [
+Summit:
+]
          
+
+
+
          
+Agree. The need for aligned_union is compelling enough to reinstate.
+
          
+
+
          [
+Post Summit, Alisdair adds:
+]
          
+
+
+
          
+paper
+N2843
+proposes an extension to the [[align]] attribute
+that further diminishes the need for this template.  Recommend NAD.
+
          
+
+
          [
+2009-10 Santa Cruz:
+]
          
+
+
+
          
+Mark NAD as suggested.
+
          
+
+
+
+
          Proposed resolution:
          
+
+
+
+
+
 
          
 
          1022. Response to UK 212
          
-
          Section: 20.8.10.7 [util.dynamic.safety] Status: NAD Editorial
+
          Section: 20.8.15.6 [util.dynamic.safety] Status: NAD Editorial
  Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-03-12
          
 
          View all other issues in [util.dynamic.safety].
          
 
          View all issues with NAD Editorial status.
          
@@ -25044,7 +31318,7 @@ at the next meeting.
 
 
          
 The pointer-safety API is nothing to do with smart pointers, so does not
-belong in 20.8.10 [util.smartptr]. In fact it is a set of language
+belong in 20.8.15 [util.smartptr]. In fact it is a set of language
 support features are really belongs in clause 18 [language.support], with the contents declared in a header that
 deals with language-support of memory management.
 
          
@@ -25072,7 +31346,7 @@ declaration should stay in
 
 
          
 
          1023. Response to DE 22
          
-
          Section: 20.7.16.2 [func.wrap.func] Status: NAD Editorial
+
          Section: 20.7.15.2 [func.wrap.func] Status: NAD Editorial
  Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-07-13
          
 
          View all other issues in [func.wrap.func].
          
 
          View all issues with NAD Editorial status.
          
@@ -25127,7 +31401,7 @@ Move to NAD Editorial.
 
          
 
 
          
-Change synopsis in Class template function 20.7.16.2 [func.wrap.func]:
+Change synopsis in Class template function 20.7.15.2 [func.wrap.func]:
 
          
 
 
          template<Returnable R, CopyConstructible... ArgTypes> 
@@ -25141,7 +31415,7 @@ class function<R(ArgTypes...)>
 
          
 
 
          
-Add new p1/p2 before 20.7.16.2.1 [func.wrap.func.con]:
+Add new p1/p2 before 20.7.15.2.1 [func.wrap.func.con]:
 
          
 
 
          
@@ -25171,7 +31445,7 @@ returning R.
 
 
          
 
          1024. Response to JP 39
          
-
          Section: 20.7.16.2 [func.wrap.func] Status: NAD Concepts
+
          Section: 20.7.15.2 [func.wrap.func] Status: NAD Concepts
  Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-07-16
          
 
          View all other issues in [func.wrap.func].
          
 
          View all issues with NAD Concepts status.
          
@@ -25217,7 +31491,7 @@ Constructors have no definition.
 
 
          Proposed resolution:
          
 
          
-Correct as follows in 20.7.16.2 [func.wrap.func] (class definition)
+Correct as follows in 20.7.15.2 [func.wrap.func] (class definition)
 
          
 
 
           template<class F, Allocator Alloc>
@@ -25239,7 +31513,7 @@ Correct as follows in 20.7.16.2 [func.wrap.func] (class definition)
 
 
          
 
          1025. Response to UK 208
          
-
          Section: 20.7.17 [unord.hash] Status: NAD Future
+
          Section: 20.7.16 [unord.hash] Status: NAD Future
  Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-03-12
          
 
          View other active issues in [unord.hash].
          
 
          View all other issues in [unord.hash].
          
@@ -25309,7 +31583,7 @@ possibly enable_shared_from_this.
 
 
          
 
          1027. Response to UK 213
          
-
          Section: 20.8.4 [default.allocator] Status: NAD Concepts
+
          Section: 20.8.8 [default.allocator] Status: NAD Concepts
  Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-07-15
          
 
          View all issues with NAD Concepts status.
          
 
          Discussion:
          
@@ -25354,7 +31628,7 @@ Agree as stated. A future paper will address additional related issues.
 
 
          
 
          1028. Response to UK 214
          
-
          Section: 20.8.6 [storage.iterator] Status: NAD Concepts
+
          Section: 20.8.10 [storage.iterator] Status: NAD Concepts
  Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-07-16
          
 
          View all issues with NAD Concepts status.
          
 
          Discussion:
          
@@ -25402,7 +31676,7 @@ template <class ForwardIterator OutputIter
-20.8.6 [storage.iterator] p1
+20.8.10 [storage.iterator] p1
 
          
 
          
 Replace class template definition with:
@@ -25452,7 +31726,7 @@ require some kind of proxy formulation to support generalised InputIterators.
 
 
          
 
          1029. Response to UK 210
          
-
          Section: 20.8.8 [specialized.algorithms] Status: NAD Concepts
+
          Section: 20.8.13 [specialized.algorithms] Status: NAD Concepts
  Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-07-16
          
 
          View all other issues in [specialized.algorithms].
          
 
          View all issues with NAD Concepts status.
          
@@ -25566,7 +31840,7 @@ Update as follows:
 
          
 
 
          
-uninitialized_copy 20.8.8.2 [uninitialized.copy]
+uninitialized_copy 20.8.13.2 [uninitialized.copy]
 
          
 
 
          template <class InputIterator InIter,
@@ -25620,7 +31894,7 @@ uninitialized_copy 20.8.8.2 [uninitialized.copy]
 
 
 
          
-uninitialized_fill 20.8.8.3 [uninitialized.fill]
+uninitialized_fill 20.8.13.3 [uninitialized.fill]
 
          
 
 
          template <class ForwardIterator Iter, class ObjectType T>
@@ -25643,7 +31917,7 @@ uninitialized_fill 20.8.8.3 [uninitialized.fill]
 
 
 
          
-uninitialized_fill_n 20.8.8.4 [uninitialized.fill.n]
+uninitialized_fill_n 20.8.13.4 [uninitialized.fill.n]
 
          
 
 
          template <class ForwardIterator Iter, class IntegralLike Size, class ObjectType T> 
@@ -25669,6 +31943,126 @@ uninitialized_fill_n 20.8.8.4 [uninitialized.fill.n]
 
 
 
+
          
+
          1031. Response to US 78
          
+
          Section: 20.8.15.2 [util.smartptr.shared] Status: NAD Future
+ Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-10-20
          
+
          View all other issues in [util.smartptr.shared].
          
+
          View all issues with NAD Future status.
          
+
          Discussion:
          
+
+
          Addresses US 78
          
+
+
          
+There is presently no way to convert directly from a shared_ptr to a
+unique_ptr. Add an interface that performs the conversion. 
+
          
+
+
          [
+Summit:
+]
          
+
+
+
          
+We look forward to a paper on this topic. We recommend no action until a
+paper is available. We believe that the shared pointer must use the default
+deleter for the conversion to succeed.
+
          
+
+
          [
+Peter Dimov adds:
+]
          
+
+
+
          
+This is basically a request for shared_ptr<>::release in
+disguise, with all the associated problems. Not a good idea.
+
          
+
+
          [
+2009-07 post-Frankfurt:
+]
          
+
+
+
          
+
          
+The rationale for the omission of a release() member function from shared_ptr is given in:
+http://www.boost.org/doc/libs/1_39_0/libs/smart_ptr/shared_ptr.htm
+
          
+
          
+The implementation of such a member is non-trivial (and maybe
+impossible), because it would need to account for the deleter.
+
          
+
          
+
+
          [
+2009-07-26 Howard sets to Tentatively NAD Future.
+]
          
+
+
+
          
+
          
+I took an online poll and got 3 votes for NAD and 3 for NAD Future.  Personally
+I prefer NAD Future as this does refer to an extension that could conceivably be
+considered beyond C++0X.
+
          
+
+
          
+However such an extension would need to solve a couple of problems:
+
          
+
+
            
+
          1. What is the interface for such a conversion when the shared_ptr does
+not have unique ownership?  Throw an exception?  Create a null unique_ptr?
+Undefined behavior?
+
            2. 
+
+
          2. 
+
            
+How does one handle custom deleters given to the shared_ptr constructor?
+
            
+
            
+I do not believe it is possible to implement a general answer to this question.
+The shared_ptr deleter is a run time (or construction time) characteristic.
+The unique_ptr deleter is a compile time characteristic.  In general one
+can not know to what type of unqiue_ptr you are converting to.
+
            
+
            
+One answer is for the user of the conversion to specify the deleter type and perhaps
+throw an exception if the specification turns out to be incorrect.
+
            
+
            
+Another answer is for the conversion to only be valid when the underlying deleter
+is default_delete.  We would probalby need to specify that this is indeed the
+underlying deleter of a shared_ptr when a custom deleter is not given in
+the constructor.
+
            
+
            3. 
+
          
+
+
          
+At any rate, there are non-trivial design issues which would need to be implemented
+and tested in the field for usability prior to standardization.
+
          
+
          
+
+
          [
+2009 Santa Cruz:
+]
          
+
+
+
          
+Moved to NAD Future.
+
          
+
+
+
+
          Proposed resolution:
          
+
+
+
+
+
 
          
 
          1032. Response to JP 45
          
 
          Section: 20.9 [time] Status: NAD Concepts
@@ -25710,10 +32104,105 @@ this topic. We recommend no action until a paper is available.
 
 
 
+
          
+
          1035. Response to UK 226
          
+
          Section: 23.2.1 [container.requirements.general] Status: NAD
+ Submitter: Alisdair Meredith Opened: 2009-03-12  Last modified: 2009-10-20
          
+
          View other active issues in [container.requirements.general].
          
+
          View all other issues in [container.requirements.general].
          
+
          View all issues with NAD status.
          
+
          Discussion:
          
+
+
          Addresses UK 226
          
+
+
          
+<array> must be added to this list. In particular it
+doesn't satisfy: - no swap() function invalidates any
+references, pointers, or iterators referring to the elements of the
+containers being swapped. and probably doesn't satisfy: - no
+swap() function throws an exception.
+
          
+
          
+If <array> remains a container, this will have to also
+reference array, which will then have to say which of these
+points it satisfies.
+
          
+
+
          [
+Summit:
+]
          
+
+
+
          
+Agree. The proposed resolution is incomplete. Further work required.
+
          
+
+
          [
+2009-05-01 Daniel adds:
+]
          
+
+
+
          
+Issue 1099 also suggests
+adding move constructor to this.
+
          
+
+
          [
+2009-07 post-Frankfurt:
+]
          
+
+
+
          
+Howard is to draft a note that explains what happens to references.
+
          
+
+
          [
+2009-10 Santa Cruz:
+]
          
+
+
+
          
+Mark as NAD.  No consensus for change.
+
          
+
+
+
+
          [
+2009-08-01 Howard provided wording.
+]
          
+
+
+
          Proposed resolution:
          
+
          
+Add a paragraph to 23.3.1.2 [array.special]:
+
          
+
+
          template <Swappable T, size_t N> void swap(array<T,N>& x, array<T,N>& y);
+
          
+
          
+
          
+Effects:
+
          
+
          swap_ranges(x.begin(), x.end(), y.begin());
+
          
+
+
          
+[Note:
+Outstanding iterators, references and pointers may be invalidated.
+— end note]
+
          
+
          
+
          
+
+
+
+
+
 
          
 
          1036. Response to UK 231
          
 
          Section: 23.2.3 [sequence.reqmts] Status: NAD Concepts
  Submitter: Alisdair Meredith Opened: 2009-03-12  Last modified: 2009-07-15
          
+
          View other active issues in [sequence.reqmts].
          
 
          View all other issues in [sequence.reqmts].
          
 
          View all issues with NAD Concepts status.
          
 
          Discussion:
          
@@ -25749,6 +32238,1565 @@ has constraints similar to
 
 
 
+
          
+
          1041. Response to UK 239
          
+
          Section: 23.2.4 [associative.reqmts] Status: NAD Future
+ Submitter: Alisdair Meredith Opened: 2009-03-12  Last modified: 2009-10-20
          
+
          View other active issues in [associative.reqmts].
          
+
          View all other issues in [associative.reqmts].
          
+
          View all issues with NAD Future status.
          
+
          Discussion:
          
+
+
          Addresses UK 239
          
+
+
          
+It is not possible to take a move-only key out of an unordered
+container, such as (multi)set or
+(multi)map, or the new unordered containers.
+
          
+
+
          
+Add below a.erase(q), a.extract(q), with the following notation:
+
          
+
          
+a.extract(q)>, Return type pair<key, iterator>
+Extracts the element pointed to by q and erases it from the
+set. Returns a pair containing the value pointed to by
+q and an iterator pointing to the element immediately
+following q prior to the element being erased. If no such
+element exists,returns a.end().
+
          
+
+
          [
+Summit:
+]
          
+
+
+
          
+We look forward to a paper on this topic. We recommend no action until a
+paper is available. The paper would need to address exception safety.
+
          
+
+
          [
+Post Summit Alisdair adds:
+]
          
+
+
+
          
+Would value_type be a better return type than key_type?
+
          
+
+
          [
+2009-07 post-Frankfurt:
+]
          
+
+
+
          
+Leave Open. Alisdair to contact Chris Jefferson about this.
+
          
+
+
          [
+2009-09-20 Howard adds:
+]
          
+
+
+
          
+See the 2009-09-19 comment of 839 for an API which
+accomplishes this functionality and also addresses several other use
+cases which this proposal does not.
+
          
+
+
          [
+2009-10 Santa Cruz:
+]
          
+
+
+
          
+Mark as NAD Future. No consensus to make the change at this time.
+
          
+
+
+
+
          Proposed resolution:
          
+
          
+In 23.2.4 [associative.reqmts] Table 85, add:
+
          
+
+
          
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
          Table 85 --  Associative container requirements (in addition to container)
          ExpressionReturn typeAssertion/note
          pre-/post-condition          		Complexity
          a.erase(q).........
          a.extract(q)pair<key_type, iterator>Extracts the element pointed to by q and erases it from the set. 
+Returns a pair containing the value pointed to by q and an iterator
+pointing to the element immediately following q prior to the element being
+erased. If no such element 
+exists, returns a.end().amortized constant
          
+
          
+
+
          
+In 23.2.5 [unord.req] Table 87, add:
+
          
+
+
          
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
          Table 87 -- Unordered associative container requirements (in addition to container)
          ExpressionReturn typeAssertion/note
          pre-/post-condition          		Complexity
          a.erase(q).........
          a.extract(q)pair<key_type, iterator>Extracts the element pointed to by q and erases it from the set. 
+Returns a pair containing the value pointed to by q and an iterator
+pointing to the element immediately following q prior to the element being
+erased. If no such element 
+exists, returns a.end().amortized constant
          
+
          
+
+
+
+
+
+
          
+
          1042. Response to UK 244
          
+
          Section: 23.3 [sequences] Status: NAD
+ Submitter: Alisdair Meredith Opened: 2009-03-12  Last modified: 2009-10-23
          
+
          View all other issues in [sequences].
          
+
          View all issues with NAD status.
          
+
          Discussion:
          
+
+
          Addresses UK 244
          
+
+
          
+The validity of the expression &a[n] == &a[0] + n is contingent on
+operator& doing the "right thing" (as captured by the CopyConstructible
+requirements in table 30 in C++2003). However this constraint has been
+lost in the Concepts of C++0x. This applies to vector and array (it
+actually applies to string also, but that's a different chapter, so I'll
+file a separate comment there and cross-reference).
+
          
+
+
          
+Suggested solution:
+
          
+
+
          
+Define a ContiguousStrorage and apply it to
+vector, array and string.
+
          
+
+
          [
+Summit:
+]
          
+
+
+
          
+Agree with the issue but not the details of the proposed solution. Walter to
+provide wording for the new concept.
+
          
+
+
          [
+Post Summit Alisdair adds:
+]
          
+
+
+
          
+Another LWG subgroup wondered if this concept
+should extend to complex<T>, and so not be built on the container concept at
+all?
+
          
+
+
          [
+2009-07 post-Frankfurt:
+]
          
+
+
+
          
+Leave Open, pending a post-Concepts Working Draft.
+
          
+
+
          [
+2009-10 Santa Cruz:
+]
          
+
+
+
          
+Mark issue 1042 as NAD, in rationale state that this was solved by removal of concepts.
+
          
+
+
+
+
          Proposed resolution:
          
+
          
+Add to <container_concepts> synopsis in  [container.concepts]
+
          
+
+
          concept< typename C > ContiguousStorageContainer see below;
+
          
+
+
          
+Add a new section to the end of  [container.concepts]
+
          
+
+
          
+
          
+23.1.6.x ContiguousStorageContainer concept [container.concepts.contiguous]
+
          
+
+
          concept ContiguousStorageContainer< typename C >
+  : Container<C>
+{
+  value_type* data(C&);
+
+  axiom Contiguity(C& c, size_type i) {
+    if( i < size(c) ) {
+         addressof( * (data(c) + i) )
+      == addressof( * advance(data(c), i) );
+    }
+  }
+}
+
          
+
+
          
+The ContiguousStorageContainer concept describes a container whose elements
+are allocated in a single region of memory, and are stored sequentially
+without intervening padding other than to meet alignment requirements.
+For example, the elements may be stored in a
+single array of suitable length.
+
          
+
+
          value_type * data( C& );
+
          
+
+
          
+Returns: a pointer to the first element in the region of storage.
+Result is unspecified for an empty container.
+
          
+
+
          
+
+
          
+Change 23.3.1 [array] p1:
+
          
+
+
          
+-1- The header <array> defines a class template for
+storing fixed-size sequences of objects. An array supports
+random access iterators. An instance of array<T, N>
+stores N elements of type T, so that size() ==
+N is an invariant. The elements of an array are stored
+contiguously, meaning that if a is an
+array<T, N> then it obeys the identity &a[n]
+== &a[0] + n for all 0 <= n < N
+satisfies the concept ContiguousStorageContainer< array<T,
+N>>.
+
          
+
+
          
+Add to the synopsis in 23.3.1 [array]:
+
          
+
+
              ...
+    T * data(); 
+    const T * data() const; 
+  };
+
+  template< typename T, size_t N >
+    concept_map ContiguousStorageContainer< array<T, N>> {};
+} 
+
          
+
+
          
+Change 23.3.6 [vector] p1:
+
          
+
+
          
+A vector is a sequence container that supports random access
+iterators. In addition, it supports (amortized) constant time insert and
+erase operations at the end; insert and erase in the middle take linear
+time. Storage management is handled automatically, though hints can be
+given to improve efficiency. The elements of a vector are stored
+contiguously, meaning that if v is a
+vector<T, Alloc> (where T is some
+type other than bool), then it obeys the
+identity &v[n] == &v[0] + n for all 0 <= n <
+v.size() satisfies the concept ContiguousStorageContainer<
+vector< T, Alloc>>.
+
          
+
+
          
+Add at the end of the synopsis in 23.3.6 [vector] p2:
+
          
+
+
          template< typename T, typename A >
+  requires !SameType< T, bool >
+  concept_map ContiguousStorageContainer< vector<T, A>> {};
+
          
+
+
+
+
          Rationale:
          
+Solved by removal of concepts.
+
+
+
+
+
+
          
+
          1043. Response to US 91
          
+
          Section: 29.6 [atomics.types.operations] Status: NAD Editorial
+ Submitter: Alisdair Meredith Opened: 2009-03-12  Last modified: 2009-10-26
          
+
          View all other issues in [atomics.types.operations].
          
+
          View all issues with NAD Editorial status.
          
+
          Discussion:
          
+
+
          Addresses US 91
          
+
+
          
+It is unclear whether or not a failed compare_exchange is a RMW operation
+(as used in 1.10 [intro.multithread]).
+
          
+
+
          
+Suggested solution:
+
          
+
+
          
+Make failing compare_exchange operations not be RMW.
+
          
+
+
          [
+Anthony Williams adds:
+]
          
+
+
+
          
+In 29.6 [atomics.types.operations] p18 it says that "These
+operations are atomic read-modify-write operations" (final sentence).
+This is overly restrictive on the implementations of
+compare_exchange_weak and compare_exchange_strong on platforms without a
+native CAS instruction.
+
          
+
+
+
          [
+Summit:
+]
          
+
+
+
          
+Group agrees with the resolution as proposed by Anthony Williams in the attached note.
+
          
+
+
          [
+Batavia (2009-05):
+]
          
+
+
          
+We recommend the proposed resolution be reviewed
+by members of the Concurrency Subgroup.
+
          
+
+
          [
+2009-07 post-Frankfurt:
+]
          
+
+
+
          
+This is likely to be addressed by Lawrence's upcoming paper. He will
+adopt the proposed resolution.
+
          
+
+
          [
+2009-08-17 Handled by
+N2925.
+]
          
+
+
+
          [
+2009-10 Santa Cruz:
+]
          
+
+
+
          
+NAD Editorial.  Solved by
+N2992.
+
          
+
+
+
+
          Proposed resolution:
          
+
          
+Change 29.6 [atomics.types.operations] p18:
+
          
+
+
          
+-18- Effects: Atomically, compares the value pointed to by
+object or by this for equality with that in
+expected, and if true, replaces the value pointed to by
+object or by this with desired, and if false, updates
+the value in expected with the value pointed to by
+object or by this. Further, if the comparison is true,
+memory is affected according to the value of success, and if the
+comparison is false, memory is affected according to the value of
+failure. When only one memory_order argument is
+supplied, the value of success is order, and the value
+of failure is order except that a value of
+memory_order_acq_rel shall be replaced by the value
+memory_order_acquire and a value of
+memory_order_release shall be replaced by the value
+memory_order_relaxed. If the comparison is true, 
+Tthese operations are atomic
+read-modify-write operations (1.10). 
+If the comparison is false, these
+operations are atomic load operations.
+
          
+
+
+
+
+
+
+
          
+
          1046. Response to UK 329
          
+
          Section: 30.6 [futures] Status: NAD Editorial
+ Submitter: Alisdair Meredith Opened: 2009-03-12  Last modified: 2009-10-26
          
+
          View all other issues in [futures].
          
+
          View all issues with NAD Editorial status.
          
+
          Discussion:
          
+
+
          Addresses UK 329
          
+
+
          
+future, promise and packaged_task provide a
+framework for creating future values, but a simple function to tie all
+three components together is missing. Note that we only need a *simple*
+facility for C++0x. Advanced thread pools are to be left for TR2.
+
          
+
+
          
+Simple Proposal:
+
          
+
+
          
+Provide a simple function along the lines of: 
+
          
+
          template< typename F, typename ... Args >
+  requires Callable< F, Args... >
+    future< Callable::result_type > async( F&& f, Args && ... ); 
+
          
+
+
          
+Semantics are similar to creating a thread object with a packaged_task
+invoking f with forward<Args>(args...)
+but details are left unspecified to allow different scheduling and thread
+spawning implementations. 
+
          
+
          
+It is unspecified whether a task submitted to async is run on its own thread
+or a thread previously used for another async task. If a call to async
+succeeds, it shall be safe to wait for it from any thread. 
+
          
+
          
+The state of thread_local variables shall be preserved during async calls. 
+
          
+
          
+No two incomplete async tasks shall see the same value of
+this_thread::get_id(). 
+
          
+
          
+[Note: this effectively forces new tasks to be run on a new thread, or a
+fixed-size pool with no queue. If the 
+library is unable to spawn a new thread or there are no free worker threads
+then the async call should fail. --end note] 
+
          
+
+
          [
+Summit:
+]
          
+
+
+
          
+
          
+The concurrency subgroup has revisited this issue and decided that it
+could be considered a defect according to the Kona compromise. A task
+group was formed lead by Lawrence Crowl and Bjarne Stroustrup to write a
+paper for Frankfort proposing a simple asynchronous launch facility
+returning a future. It was agreed that the callable must be run on a
+separate thread from the caller, but not necessarily a brand-new thread.
+The proposal might or might not allow for an implementation that uses
+fixed-size or unlimited thread pools.
+
          
+
          
+Bjarne in c++std-lib-23121: I think that what we agreed was that to
+avoid deadlock async() would almost certainly be specified to  launch in
+a different thread from the thread that executed async(), but I don't
+think it was a specific design constraint.
+
          
+
          
+
+
          [
+2009-10 Santa Cruz:
+]
          
+
+
+
          
+Proposed resolution: see
+N2996
+(Herb's and Lawrence's paper on Async). Move state to NAD editorial.
+
          
+
+
+
+
          Proposed resolution:
          
+
+
+
+
+
+
          
+
          1047. Response to UK 334
          
+
          Section: 30.6.6 [futures.unique_future] Status: NAD Editorial
+ Submitter: Alisdair Meredith Opened: 2009-03-12  Last modified: 2009-10-26
          
+
          View all other issues in [futures.unique_future].
          
+
          View all issues with NAD Editorial status.
          
+
          Discussion:
          
+
+
          Addresses UK 334
          
+
+
          
+Behaviour of get() is undefined if calling get() while
+not is_ready(). The intent is that get() is a blocking
+call, and will wait for the future to become ready.
+
          
+
+
          [
+Summit:
+]
          
+
+
+
          
+
          
+Agree, move to Review.
+
          
+
          
+
+
          [
+2009-04-03 Thomas J. Gritzan adds:
+]
          
+
+
+
          
+
          
+This issue also applies to shared_future::get().
+
          
+
+
          
+Suggested wording:
+
          
+
+
          
+Add a paragraph to  [futures.shared_future]:
+
          
+
+
          void shared_future<void>::get() const;
+
          
+
          
+Effects: If is_ready() would return false, block on the asynchronous 
+result associated with *this.
+
          
+
          
+
          
+
+
          [
+Batavia (2009-05):
+]
          
+
+
          
+It is not clear to us that this is an issue,
+because the proposed resolution's Effects clause seems to duplicate
+information already present in the Synchronization clause.
+Keep in Review status.
+
          
+
+
          [
+2009-10 Santa Cruz:
+]
          
+
+
+
          
+NAD Editorial.  Solved by
+N2997.
+
          
+
+
+
+
          Proposed resolution:
          
+
          
+Add a paragraph to 30.6.6 [futures.unique_future]:
+
          
+
+
          R&& unique_future::get(); 
+R& unique_future<R&>::get(); 
+void unique_future<void>::get();
+
          
+
          
+
          Note:...
          
+
          
+Effects: If is_ready() would return false,
+block on the asynchronous result associated with *this.
+
          
+
          
+Synchronization: if *this is associated with a
+promise object, the completion of set_value() or
+set_exception() to that promise happens before (1.10)
+get() returns.
+
          
+
          
+
          
+
+
+
+
+
+
          
+
          1048. Response to UK 335
          
+
          Section: 30.6.6 [futures.unique_future] Status: NAD Editorial
+ Submitter: Alisdair Meredith Opened: 2009-03-12  Last modified: 2009-10-26
          
+
          View all other issues in [futures.unique_future].
          
+
          View all issues with NAD Editorial status.
          
+
          Discussion:
          
+
+
          Addresses UK 335
          
+
+
          
+std::unique_future is MoveConstructible, so you can transfer the
+association with an asynchronous result from one instance to another.
+However, there is no way to determine whether or not an instance has
+been moved from, and therefore whether or not it is safe to wait for it.
+
          
+
+
          std::promise<int> p;
+std::unique_future<int> uf(p.get_future());
+std::unique_future<int> uf2(std::move(uf));
+uf.wait(); // oops, uf has no result to wait for. 
+
          
+
+
          
+Suggest we add a waitable() function to unique_future
+(and shared_future) akin to std::thread::joinable(),
+which returns true if there is an associated result to wait for
+(whether or not it is ready).
+
          
+
+
          
+Then we can say:
+
          
+
+
          if(uf.waitable()) uf.wait();
+
          
+
+
          [
+Summit:
+]
          
+
+
+
          
+
          
+Create an issue. Requires input from Howard. Probably NAD.
+
          
+
          
+
+
          [
+Post Summit, Howard thows in his two cents:
+]
          
+
+
+
          
+
          
+Here is a copy/paste of my last prototype of unique_future which was
+several years ago.  At that time I was calling unique_future future:
+
          
+
+
          template <class R>
+class future
+{
+public:
+    typedef R result_type;
+private:
+    future(const future&);// = delete;
+    future& operator=(const future&);// = delete;
+
+    template <class R1, class F1> friend class prommise;
+public:
+    future();
+    ~future();
+
+    future(future&& f);
+    future& operator=(future&& f);
+
+    void swap(future&& f);
+
+    bool joinable() const;
+    bool is_normal() const;
+    bool is_exceptional() const;
+    bool is_ready() const;
+
+    R get();
+
+    void join();
+    template <class ElapsedTime>
+        bool timed_join(const ElapsedTime&);
+};
+
          
+
+
          
+shared_future had a similar interface.  I intentionally reused
+the thread interface where possible to lessen the learning
+curve std::lib clients will be faced with.
+
          
+
          
+
+
          [
+2009-10 Santa Cruz:
+]
          
+
+
+
          
+NAD Editorial.  Solved by
+N2997.
+
          
+
+
+
+
          Proposed resolution:
          
+
+
+
+
+
+
          
+
          1049. Response to UK 339
          
+
          Section: 30.6.5 [futures.promise] Status: NAD Editorial
+ Submitter: Alisdair Meredith Opened: 2009-03-12  Last modified: 2009-10-26
          
+
          View all other issues in [futures.promise].
          
+
          View all issues with NAD Editorial status.
          
+
          Discussion:
          
+
+
          Addresses UK 339
          
+
+
          
+Move assignment is goiing in the wrong direction, assigning from
+*this to the passed rvalue, and then returning a reference to
+an unusable *this.
+
          
+
+
          [
+Summit:
+]
          
+
+
+
          
+
          
+Agree, move to Review.
+
          
+
          
+
+
          [
+Batavia (2009-05):
+]
          
+
+
          
+We recommend deferring this issue until after Detlef's paper (on futures)
+has been issued.
+
          
+
+
          [
+2009-10 Santa Cruz:
+]
          
+
+
+
          
+NAD Editorial.  Solved by
+N2997.
+
          
+
+
+
+
          Proposed resolution:
          
+
          
+Strike 30.6.5 [futures.promise] p6 and change p7:
+
          
+
+
          promise& operator=(promise&& rhs);
+
          
+
          
+
          
+-6- Effects: move assigns its associated state to rhs.
+
          
+
          
+-7- Postcondition: *this has no associated
+state. associated state of *this is the same as the
+associated state of rhs before the call. rhs has no
+associated state.
+
          
+
          
+
          
+
+
+
+
+
+
+
          
+
          1050. Response to UK 340
          
+
          Section: 30.6.5 [futures.promise] Status: NAD Editorial
+ Submitter: Alisdair Meredith Opened: 2009-03-12  Last modified: 2009-10-26
          
+
          View all other issues in [futures.promise].
          
+
          View all issues with NAD Editorial status.
          
+
          Discussion:
          
+
+
          Addresses UK 340
          
+
+
          
+There is an implied postcondition for get_future() that the state of the
+promise is transferred into the future leaving the promise with no
+associated state. It should be spelled out.
+
          
+
+
          [
+Summit:
+]
          
+
+
+
          
+
          
+Agree, move to Review.
+
          
+
          
+
+
          [
+2009-04-03 Thomas J. Gritzan adds:
+]
          
+
+
+
          
+
          
+promise::get_future() must not invalidate the state of the promise object. 
+
          
+
          
+A promise is used like this: 
+
          
+
          promise<int> p; 
+unique_future<int> f = p.get_future(); 
+// post 'p' to a thread that calculates a value 
+// use 'f' to retrieve the value. 
+
          
+
          
+So get_future() must return an object that shares the same associated 
+state with *this. 
+
          
+
          
+But still, this function should throw an future_already_retrieved error 
+when it is called twice. 
+
          
+
          
+packaged_task::get_future() throws std::bad_function_call if its future
+was already retrieved. It should throw 
+future_error(future_already_retrieved), too. 
+
          
+
          
+Suggested resolution: 
+
          
+
          
+Replace p12/p13 30.6.5 [futures.promise]: 
+
          
+
          
+
          
+-12- Throws: future_error if *this has no associated state
+the future has already been retrieved.
+
          
+
          
+-13- Error conditions: future_already_retrieved if *this
+has no associated state
+the future associated with 
+the associated state has already been retrieved.
+
          
+
          
+Postcondition: The returned object and *this share the associated state.
+
          
+
          
+
          
+Replace p14 30.6.10 [futures.task]: 
+
          
+
          
+
          
+-14- Throws: std::bad_function_call future_error if the future associated with
+the task has already been retrieved.
+
          
+
+
          
+Error conditions: future_already_retrieved if the future associated with 
+the task has already been retrieved. 
+
          
+
          
+Postcondition: The returned object and *this share the associated task.
+
          
+
          
+
          
+
+
          [
+Batavia (2009-05):
+]
          
+
+
          
+Keep in Review status
+pending Detlef's forthcoming paper on futures.
+
          
+
+
          [
+2009-10 Santa Cruz:
+]
          
+
+
+
          
+NAD Editorial.  Solved by
+N2997.
+
          
+
+
+
+
          Proposed resolution:
          
+
          
+Add after p13 30.6.5 [futures.promise]:
+
          
+
+
          unique_future<R> get_future();
+
          
+
          
+
          
+-13- ...
+
          
+
          
+Postcondition: *this has no associated state.
+
          
+
          
+
          
+
+
+
+
+
+
+
          
+
          1051. Response to UK 279
          
+
          Section: 24.5.1.3.12 [reverse.iter.opindex], 24.5.3.3.12 [move.iter.op.index] Status: NAD
+ Submitter: Alisdair Meredith Opened: 2009-03-12  Last modified: 2009-10-24
          
+
          View all issues with NAD status.
          
+
          Discussion:
          
+
+
          Addresses UK 279
          
+
+
          
+The reason the return type became unspecified is LWG issue 386. This
+reasoning no longer applies as there are at least two ways to get the right
+return type with the new language facilities added since the previous
+standard. 
+
          
+
+
          
+Proposal: Specify the return type using either decltype or the Iter concept_map.
+
          
+
+
          [
+Summit:
+]
          
+
+
+
          
+
          
+Under discussion. This is a general question about all iterator
+adapters.
+
          
+
          
+
+
          [
+Howard adds post Summit:
+]
          
+
+
+
          
+I am requesting test cases to demonstrate a position.
+
          
+
+
          [
+2009-07-24 Daniel adds:
+]
          
+
+
+
          
+
          
+I recommend NAD. Without concepts we can no longer
+restrict this member in a trivial way. Using decltype the
+declaration would be along the lines of
+
          
+
          static const Iter& __base(); // not defined
+auto operator[](difference_type n) const -> decltype(__base()[-n-1]);
+
          
+
+
          
+but once reverse_iterator is instantiated for some given type
+Iter which cannot form a well-formed expression __base()[-n-1]
+this would cause an ill-formed function declaration, diagnostic
+required, and no silent SFINAE elimination.
+
          
+
+
          
+
+
          [
+2009-10 Santa Cruz:
+]
          
+
+
+
          
+Moved to NAD.
+
          
+
+
          [
+2009-10-22 Daniel adds:
+]
          
+
+
+
          
+
          
+IMO, my original comment regarding ill-formedness of the described
+construction is still correct, but I must add that I should weaken my
+assertion "Without concepts we can no longer restrict this member in
+a trivial way".
+
          
+
+
          
+In fact with the existence of default template arguments for function
+templates it is not too hard to implement this like as follows, which
+shows that we can indeed simulate to some sense constrained
+member functions in C++0x.
+
          
+
+
          
+My example does not really proof that the specification is easy, but
+it should be possible. I assume that the implementation would not
+be ABI compatible, though.
+
          
+
+
          
+It is now your own decision how to proceed ;-)
+
          
+
+
          #include <type_traits>
+#include <cstddef>
+
+template<class T>
+typename std::add_rvalue_reference<T>::type declval();
+
+template<class It>
+struct reverse_iterator {
+    It base;
+    
+    typedef std::ptrdiff_t difference_type;
+    
+    template<class U = It, class Res =
+     decltype(declval<const U&>()[declval<difference_type>()])
+    >
+    Res operator[](difference_type n) const  {
+        return base[-n-1];
+    }    
+};
+
+struct MyIter {
+};
+
+int main() {
+    reverse_iterator<int*> ri;
+    ri[0] = 2;
+    reverse_iterator<MyIter> ri2;
+}
+
          
+
+
          
+The above declaration could be simplified, but the ideal solution
+
          
+
+
          template<class U = It>
+  decltype(declval<const U&>()[declval<difference_type>()])
+     operator[](difference_type n) const;
+
          
+
+
          
+does not work yet on gcc 4.4.1.
+
          
+
+
          
+
+
+
+
+
          Proposed resolution:
          
+
+
+
+
+
+
          
+
          1053. Response to UK 295
          
+
          Section: 25 [algorithms] Status: NAD Future
+ Submitter: Alisdair Meredith Opened: 2009-03-12  Last modified: 2009-10-23
          
+
          View other active issues in [algorithms].
          
+
          View all other issues in [algorithms].
          
+
          View all issues with NAD Future status.
          
+
          Discussion:
          
+
+
          Addresses UK 295
          
+
+
          
+There is a level of redundancy in the library specification for many
+algorithms that can be eliminated with the combination of concepts and
+default parameters for function templates. Eliminating redundancy simplified
+specification and reduces the risk of introducing accidental
+inconsistencies.
+
          
+
          
+Proposed resolution: Adopt
+N2743.
+
          
+
+
          [
+Summit:
+]
          
+
+
+
          
+
          
+NAD, this change would break code that takes the address of an
+algorithm.
+
          
+
          
+
+
          [
+Post Summit Alisdair adds:
+]
          
+
+
+
          
+
          
+Request 'Open'.  The issues in the paper go beyond just reducing
+the number of signatures, but cover unifying the idea of the ordering
+operation used by algorithms, containers and other library components.  At
+least, it takes a first pass at the problem.
+
          
+
+
          
+For me (personally) that was the more important part of the paper, and not
+clearly addressed by the Summit resolution.
+
          
+
          
+
+
          [
+2009-10 Santa Cruz:
+]
          
+
+
+
          
+Too inventive, too late, would really need a paper. Moved to NAD Future.
+
          
+
+
+
+
          Proposed resolution:
          
+
+
+
+
+
+
          
+
          1054. forward broken
          
+
          Section: 20.3.3 [forward] Status: NAD Editorial
+ Submitter: Howard Hinnant Opened: 2009-03-13  Last modified: 2009-10-26
          
+
          View all other issues in [forward].
          
+
          View all issues with NAD Editorial status.
          
+
          Discussion:
          
+
+
          
+This is a placeholder issue to track the fact that we (well I) put the standard
+into an inconsistent state by requesting that we accept
+N2844
+except for the proposed changes to [forward].
+
          
+
+
          
+There will exist in the post meeting mailing
+N2835
+which in its current state reflects the state of affairs prior to the Summit
+meeting.  I hope to update it in time for the post Summit mailing, but as I write
+this issue I have not done so yet.
+
          
+
+
          [
+Batavia (2009-05):
+]
          
+
+
          
+Move to Open, awaiting the promised paper.
+
          
+
+
          [
+2009-08-02 Howard adds:
+]
          
+
+
+
          
+
          
+My current preferred solution is:
+
          
+
+
          template <class T>
+struct __base_type
+{
+   typedef typename remove_cv<typename remove_reference<T>::type>::type type;
+};
+
+template <class T, class U,
+   class = typename enable_if<
+       !is_lvalue_reference<T>::value ||
+        is_lvalue_reference<T>::value &&
+        is_lvalue_reference<U>::value>::type,
+   class = typename enable_if<
+        is_same<typename __base_type<T>::type,
+                typename __base_type<U>::type>::value>::type>
+inline
+T&&
+forward(U&& t)
+{
+   return static_cast<T&&>(t);
+}
+
          
+
+
          
+This has been tested by Bill, Jason and myself.
+
          
+
+
          
+It allows the following lvalue/rvalue casts:
+
          
+
+
            
+
          1. 
+Cast an lvalue t to an lvalue T (identity).
+
            2. 
+
          2. 
+Cast an lvalue t to an rvalue T.
+
            3. 
+
          3. 
+Cast an rvalue t to an rvalue T (identity).
+
            4. 
+
          
+
+
          
+It disallows:
+
          
+
+
            
+
          1. 
+Cast an rvalue t to an lvalue T.
+
            2. 
+
          2. 
+Cast one type t to another type T (such as int to double).
+
            3. 
+
          
+
+
          
+"a." is disallowed as it can easily lead to dangling references.
+"b." is disallowed as this function is meant to only change the lvalue/rvalue
+characteristic of an expression.
+
          
+
+
          
+Jason has expressed concern that "b." is not dangerous and is useful in contexts
+where you want to "forward" a derived type as a base type.  I find this use case
+neither dangerous, nor compelling.  I.e. I could live with or without the "b."
+constraint.  Without it, forward would look like:
+
          
+
+
          template <class T, class U,
+   class = typename enable_if<
+       !is_lvalue_reference<T>::value ||
+        is_lvalue_reference<T>::value &&
+        is_lvalue_reference<U>::value>::type>
+inline
+T&&
+forward(U&& t)
+{
+   return static_cast<T&&>(t);
+}
+
          
+
+
          
+Or possibly:
+
          
+
+
          template <class T, class U,
+   class = typename enable_if<
+       !is_lvalue_reference<T>::value ||
+        is_lvalue_reference<T>::value &&
+        is_lvalue_reference<U>::value>::type,
+   class = typename enable_if<
+        is_base_of<typename __base_type<U>::type,
+                   typename __base_type<T>::type>::value>::type>
+inline
+T&&
+forward(U&& t)
+{
+   return static_cast<T&&>(t);
+}
+
          
+
+
+
          
+The "promised paper" is not in the post-Frankfurt mailing only because I'm waiting
+for the non-concepts draft.  But I'm hoping that by adding this information here
+I can keep people up to date.
+
          
+
          
+
+
          [
+2009-08-02 David adds:
+]
          
+
+
+
          
+
          
+forward was originally designed to do one thing: perfect forwarding.
+That is, inside a function template whose actual argument can be a const
+or non-const lvalue or rvalue, restore the original "rvalue-ness" of the
+actual argument:
+
          
+
+
          template <class T>
+void f(T&& x)
+{
+    // x is an lvalue here.  If the actual argument to f was an
+    // rvalue, pass static_cast<T&&>(x) to g; otherwise, pass x.
+    g( forward<T>(x) );
+}
+
          
+
+
          
+Attempting to engineer forward to accomodate uses other than perfect
+forwarding dilutes its idiomatic meaning.  The solution proposed here
+declares that forward<T>(x) means nothing more than static_cast<T&&>(x),
+with a patchwork of restrictions on what T and x can be that can't be
+expressed in simple English.
+
          
+
+
          
+I would be happy with either of two approaches, whose code I hope (but
+can't guarantee) I got right.
+
          
+
+
            
+
          1. 
+
            
+Use a simple definition of forward that accomplishes its original
+purpose without complications to accomodate other uses:
+
            
+
+
            template <class T, class U>
+T&& forward(U& x)
+{
+    return static_cast<T&&>(x);
+}
+
            
+
            2. 
+
+
          2. 
+
            
+Use a definition of forward that protects the user from as many
+potential mistakes as possible, by actively preventing all other
+uses:
+
            
+
+
            template <class T, class U>
+boost::enable_if_c<
+    // in forward<T>(x), x is a parameter of the caller, thus an lvalue
+    is_lvalue_reference<U>::value
+    // in caller's deduced T&& argument, T can only be non-ref or lvalue ref
+    && !is_rvalue_reference<T>::value
+    // Must not cast cv-qualifications or do any type conversions
+    && is_same<T&,U&>::value
+    , T&&>::type forward(U&& a)
+{
+    return static_cast<T&&>(a);
+}
+
            
+
            3. 
+
          
+
+
          
+
+
          [
+2009-09-27 Howard adds:
+]
          
+
+
+
          
+A paper,
+N2951,
+is available which compares several implementations (including David's) with respect to several
+use cases (including Jason's) and provides wording for one implementation.
+
          
+
+
          [
+2009-10 Santa Cruz:
+]
          
+
+
+
          
+NAD Editorial.  Solved by
+N2951.
+
          
+
+
+
+
          Proposed resolution:
          
+
+
+
+
+
+
          
+
          1055. Response to UK 98
          
+
          Section: 20.6.7 [meta.trans.other] Status: NAD Editorial
+ Submitter: Alisdair Meredith Opened: 2009-03-12  Last modified: 2009-10-26
          
+
          View all other issues in [meta.trans.other].
          
+
          View all issues with NAD Editorial status.
          
+
          Discussion:
          
+
+
          Addresses UK 98
          
+
+
          
+It would be useful to be able to determine the underlying
+type of an arbitrary enumeration type. This would allow
+safe casting to an integral type (especially needed for
+scoped enums, which do not promote), and would allow
+use of numeric_limits. In general it makes generic
+programming with enumerations easier.
+
          
+
+
          [
+Batavia (2009-05):
+]
          
+
+
          
+Pete observes (and Tom concurs)
+that the proposed resolution seems to require compiler support
+for its implementation,
+as it seems necessary to look at the range of values
+of the enumerated type.
+To a first approximation,
+a library solution could give an answer based on the size of the type.
+If the user has specialized numeric_limits for the enumerated type,
+then the library might be able to do better,
+but there is no such requirement.
+Keep status as Open
+and solicit input from CWG.
+
          
+
+
          [
+2009-05-23 Alisdair adds:
+]
          
+
+
+
          
+Just to confirm that the BSI originator of this comment assumed it did
+indeed imply a compiler intrinsic.  Rather than request a Core extension, it
+seemed in keeping with that the type traits interface provides a library API
+to unspecified compiler features - where we require several other traits
+(e.g. has_trivial_*) to get the 'right' answer now, unlike in TR1.
+
          
+
+
          [
+Addressed in N2947.
+]
          
+
+
+
          [
+2009-10 Santa Cruz:
+]
          
+
+
+
          
+NAD Editorial.  Solved by
+N2984.
+
          
+
+
+
+
          Proposed resolution:
          
+
          
+Add a new row to the table in 20.6.7 [meta.trans.other]:
+
          
+
+
          
+
+
+
+
+
+
+
+
+
+
+
+
+
          Table 41 -- Other transformations
          TemplateConditionComments
          
+template< class T > struct enum_base;
+
+T shall be an enumeration type (7.2 [dcl.enum])
+
+The member typedef type shall name the underlying type
+of the enum T.
+
          
+
          
+
+
+
+
+
 
          
 
          1057. RandomNumberEngineAdaptor
          
 
          Section: 26.5 [rand] Status: NAD Concepts
@@ -25815,6 +33863,7 @@ Move to Open.
 
          1058. New container issue
          
 
          Section: 23.2.3 [sequence.reqmts] Status: NAD Editorial
  Submitter: Alisdair Meredith Opened: 2009-03-12  Last modified: 2009-07-13
          
+
          View other active issues in [sequence.reqmts].
          
 
          View all other issues in [sequence.reqmts].
          
 
          View all issues with NAD Editorial status.
          
 
          Discussion:
          
@@ -25866,7 +33915,7 @@ element constructed from args inserted into a.
 
 
          
 
          1059. Usage of no longer existing FunctionType concept
          
-
          Section: 20.7.16.2 [func.wrap.func] Status: NAD Concepts
+
          Section: 20.7.15.2 [func.wrap.func] Status: NAD Concepts
  Submitter: Daniel Krügler Opened: 2009-03-13  Last modified: 2009-07-16
          
 
          View all other issues in [func.wrap.func].
          
 
          View all issues with NAD Concepts status.
          
@@ -25882,7 +33931,7 @@ had been
 prepared. This caused a break of the library, which already used this
 concept in the adapted definition of std::function
 (20.7 [function.objects]/2, header <functional> synopsis and
-20.7.16.2 [func.wrap.func]).
+20.7.15.2 [func.wrap.func]).
 
          
 
          
 A simple fix would be to either (a) make std::function's primary template
@@ -25968,7 +34017,7 @@ class function; // undefined
 
          4. 
 
        4. 
 
          
-Change in 20.7.16.2 [func.wrap.func]:
+Change in 20.7.15.2 [func.wrap.func]:
 
          
 
          namespace std {
 template<FunctionTypeReferentType F>
@@ -26013,7 +34062,7 @@ Move to NAD Editorial.
 
 
          
 
          1061. Bad indexing for tuple access to pair (Editorial?)
          
-
          Section: 20.3.4 [pair.astuple] Status: NAD Editorial
+
          Section: 20.3.5 [pair.astuple] Status: NAD Editorial
  Submitter: Alisdair Meredith Opened: 2009-03-13  Last modified: 2009-07-13
          
 
          View all issues with NAD Editorial status.
          
 
          Discussion:
          
@@ -26035,7 +34084,7 @@ Move to NAD Editorial.
 
 
          Proposed resolution:
          
 
          
-20.3.4 [pair.astuple] p5:
+20.3.5 [pair.astuple] p5:
 
          
 
 
          template<int size_t I, class T1, class T2> 
@@ -26049,9 +34098,70 @@ Move to NAD Editorial.
 
 
 
+
          
+
          1062. Missing insert_iterator for stacks/queues
          
+
          Section: 24.5.2 [insert.iterators] Status: NAD
+ Submitter: Alisdair Meredith Opened: 2009-03-13  Last modified: 2009-10-20
          
+
          View all other issues in [insert.iterators].
          
+
          View all issues with NAD status.
          
+
          Discussion:
          
+
+
          
+It is odd that we have an iterator to insert into a vector, but not an
+iterator to insert into a vector that is adapted as a stack. The standard
+container adapters all have a common interface to push and pop so it should
+be simple to create an iterator adapter to complete the library support.
+
          
+
+
          
+We should provide an AdaptedContainer concept supporting push and pop
+operations. Create a new insert iterator and factory function that inserts
+values into the container by calling push.
+
          
+
+
          [
+Batavia (2009-05):
+]
          
+
+
          
+
          
+Walter recommends NAD Future.
+
          
+
          
+Move to Open, and recommend deferring the issue until after the next
+Committee Draft is issued.
+
          
+
          
+
+
          [
+2009-07-29 Howard moves to Tentatively NAD Future.
+]
          
+
+
+
          
+A poll on the LWG reflector voted unanimously to move this issue to Tentatively NAD Future.
+
          
+
+
          [
+2009 Santa Cruz:
+]
          
+
+
+
          
+Moved to NAD.  The intent of these adapters are to restrict the interfaces.
+
          
+
+
+
+
          Proposed resolution:
          
+
+
+
+
+
 
          
 
          1063. 03 iterator compatibilty
          
-
          Section: D.10.4 [iterator.backward] Status: NAD Concepts
+
          Section: X [iterator.backward] Status: NAD Concepts
  Submitter: Alisdair Meredith Opened: 2009-03-15  Last modified: 2009-07-16
          
 
          View all issues with NAD Concepts status.
          
 
          Discussion:
          
@@ -26089,7 +34199,7 @@ post-remove-concepts draft.
 
 
 
          Proposed resolution:
          
-
          Change D.10 [depr.lib.iterator.primitives], Iterator primitives, as
+
          Change  [depr.lib.iterator.primitives], Iterator primitives, as
 indicated:
          
 
 
          
@@ -26098,7 +34208,7 @@ indicated:
          
   the library provides several classes and functions. Unless otherwise
   specified, these classes and functions shall be defined in header <iterator>.
          
 
          
-
          Change D.10.4 [iterator.backward], Iterator backward compatibility, as
+
          Change X [iterator.backward], Iterator backward compatibility, as
 indicated:
          
 
          
   
          The library provides concept maps that allow iterators specified with
@@ -26111,6 +34221,48 @@ indicated:
          
 
 
 
+
          
+
          1064. Response to UK 152
          
+
          Section: 17.3.15 [defns.obj.state] Status: NAD
+ Submitter: Howard Hinnant Opened: 2009-03-15  Last modified: 2009-10-23
          
+
          View all issues with NAD status.
          
+
          Discussion:
          
+
+
          Addresses UK 152
          
+
+
          
+Object state is using a definition of object (instance of a class) from
+outside the standard, rather than the 'region of storage' definiton in
+1.8 [intro.object]p1
+
          
+
+
          [
+Summit:
+]
          
+
+
          
+We think we're removing this; See X [func.referenceclosure.cons].
+
          
+
+
          [
+2009-10 Santa Cruz:
+]
          
+
+
+
          
+Mark as NAD.  This will not affect user or implementer code
+
          
+
+
+
+
          Proposed resolution:
          
+
          
+
          
+
+
+
+
+
 
          
 
          1067. simplified wording for inner_product
          
 
          Section: 26.7 [numeric.ops] Status: NAD Concepts
@@ -26178,7 +34330,7 @@ Move to Tentatively Ready.
 
 
          Proposed resolution:
          
 
          
-Change in 26.7 [numeric.ops] and  [accumulate]:
+Change in 26.7 [numeric.ops] and 26.7.1 [accumulate]:
 
          
 
 
          template <InputIterator Iter, MoveConstructible T>
@@ -26232,7 +34384,7 @@ Change in 26.7 [numeric.ops] and 26.7.4 [adjacent.difference]:
 
 
          
 
          1072. Is std::hash a constrained template or not?
          
-
          Section: 20.7.17 [unord.hash] Status: NAD Concepts
+
          Section: 20.7.16 [unord.hash] Status: NAD Concepts
  Submitter: Alisdair Meredith Opened: 2009-03-19  Last modified: 2009-07-16
          
 
          View other active issues in [unord.hash].
          
 
          View all other issues in [unord.hash].
          
@@ -26243,7 +34395,7 @@ Change in 26.7 [numeric.ops] and 26.7.4 [adjacent.difference]:
 Is std::hash a constrained template or not?
 
          
 
          
-According to Class template hash 20.7.17 [unord.hash], the definition is:
+According to Class template hash 20.7.16 [unord.hash], the definition is:
 
          
 
 
          template <class T>
@@ -26311,7 +34463,7 @@ template <ReferentType T> struct hash; // undefined
 
          5. 
 
        5. 
 
          
-In 20.7.17 [unord.hash]/1 change as indicated:
+In 20.7.16 [unord.hash]/1 change as indicated:
 
          
 
          namespace std {
  template <class T>
@@ -26324,7 +34476,7 @@ In 20.7.17 [unord.hash]/1 change as indicated:
 
          6. 
 
        6. 
 
          
-In 20.7.17 [unord.hash]/2 change as indicated:
+In 20.7.16 [unord.hash]/2 change as indicated:
 
          
 
 
          
@@ -26359,13 +34511,13 @@ In 18.7 [support.rtti]/1, header <typeinfo> synopsis change as in
 
 
          
 
          1074. concept map broken by N2840
          
-
          Section: 20.8.3 [allocator.element.concepts] Status: NAD Concepts
+
          Section: X [allocator.element.concepts] Status: NAD Concepts
  Submitter: Alisdair Meredith Opened: 2009-03-19  Last modified: 2009-07-13
          
 
          View all issues with NAD Concepts status.
          
 
          Discussion:
          
 
 
          
-p7 Allocator-related element concepts 20.8.3 [allocator.element.concepts]
+p7 Allocator-related element concepts X [allocator.element.concepts]
 
          
 
 
          
@@ -26391,7 +34543,7 @@ specialization no longer matches the original concept:
 Actually, this is incorrect,
 N2840
 says. "In section 
-20.8.3 [allocator.element.concepts] paragraph 8, modify the definition of the
+X [allocator.element.concepts] paragraph 8, modify the definition of the
 AllocatableElement concept and eliminate the related concept map:" but
 then neglects to include the red-lined text of the concept map that was
 to be eliminated. Pete also missed this, but I caught it he asked me to
@@ -26415,7 +34567,7 @@ restrictive allocator (like the scoped allocators).
 it seems to me that #1074 should be resolved as a NAD, because the
 current WP has already removed the previous AllocatableElement concept map.
 It introduced auto concept AllocatableElement instead, but as of
-20.8.3 [allocator.element.concepts]/7 this guy contains now
+X [allocator.element.concepts]/7 this guy contains now
 
          
 
          requires FreeStoreAllocatable<T>;
 void Alloc::construct(T*, Args&&...);
@@ -26438,7 +34590,7 @@ Move to NAD.
 
 
          Proposed resolution:
          
 
          
-Change 20.8.3 [allocator.element.concepts]:
+Change X [allocator.element.concepts]:
 
          
 
 
          template <Allocator Alloc, class T, class ... Args>
@@ -26455,6 +34607,260 @@ Change 20.8.3 [allocator.element.concepts]:
 
 
 
+
          
+
          1075. Response to US 65, US 74.1
          
+
          Section: 20 [utilities], 23 [containers] Status: NAD Editorial
+ Submitter: Alan Talbot Opened: 2009-03-20  Last modified: 2009-10-26
          
+
          View all other issues in [utilities].
          
+
          View all issues with NAD Editorial status.
          
+
          Discussion:
          
+
          Addresses US 65 and US 74.1
          
+
+
          US 65:
          
+
+
          
+Scoped allocators and allocator propagation traits add a small amount of
+utility at the cost of a great deal of machinery. The machinery is user
+visible, and it extends to library components that don't have any
+obvious connection to allocators, including basic concepts and simple
+components like pair and tuple.
+
+
          Suggested resolution:
          
+
+
          
+Sketch of proposed resolution: Eliminate scoped allocators, replace
+allocator propagation traits with a simple uniform rule (e.g. always
+propagate on copy and move), remove all mention of allocators from
+components that don't explicitly allocate memory (e.g. pair), and adjust
+container interfaces to reflect this simplification.
+
          
+
          
+Components that I propose eliminating include HasAllocatorType,
+is_scoped_allocator, allocator_propagation_map, scoped_allocator_adaptor,
+and ConstructibleAsElement.
+
          
+
          
+
+
          US 74.1:
          
+
+
          
+
          
+Scoped allocators represent a poor trade-off for standardization, since
+(1) scoped-allocator--aware containers can be implemented outside the
+C++ standard library but used with its algorithms, (2) scoped
+allocators only benefit a tiny proportion of the C++ community
+(since few C++ programmers even use today's allocators), and (3) all C++
+users, especially the vast majority of the C++ community that won't ever
+use scoped allocators are forced to cope with the interface complexity
+introduced by scoped allocators.
+
          
+
          
+In essence, the larger community will suffer to support a very small
+subset of the community who can already implement their own
+data structures outside of the standard library. Therefore, scoped
+allocators should be removed from the working paper.
+
          
+
          
+Some evidence of the complexity introduced by scoped allocators:
+
          
+
          
+
          
+20.3.4 [pairs], 20.5 [tuple]: Large increase in the
+number of pair and tuple constructors.
+
          
+
          
+23 [containers]: Confusing "AllocatableElement" requirements throughout.
+
          
+
          
+
          Suggested resolution:
          
+
+
          
+Remove support for scoped allocators from the working paper. This
+includes at least the following changes:
+
          
+
+
          
+
          
+Remove X [allocator.element.concepts]
+
          
+
          
+Remove 20.8.9 [allocator.adaptor]
+
          
+
          
+Remove 20.8.12 [construct.element]
+
          
+
          
+In Clause 23 [containers]: replace requirements naming the
+AllocatableElement concept with requirements naming CopyConstructible,
+MoveConstructible, DefaultConstructible, or Constructible, as
+appropriate.
+
          
+
          
+
+
          
+
+
          [
+Post Summit Alan moved from NAD to Open.
+]
          
+
+
+
          [
+2009-05-15 Ganesh adds:
+]
          
+
+
+
          
+
          
+The requirement AllocatableElement should not be replaced with
+Constructible on the emplace_xxx() functions as suggested. In the
+one-parameter case the Constructible requirement is not satisfied when
+the constructor is explicit (as per  [concept.map.fct], twelfth
+bullet) but we do want to allow explicit constructors in emplace, as the
+following example shows:
+
          
+
+
          vector<shared_ptr<int>> v;
+v.emplace_back(new int); // should be allowed
+
          
+
+
          
+If the issue is accepted and scoped allocators are removed, I suggest to
+add a new pair of concepts to  [concept.construct], namely:
+
          
+
+
          auto concept HasExplicitConstructor<typename T, typename... Args> {
+ explicit T::T(Args...);
+}
+
+auto concept ExplicitConstructible<typename T, typename... Args>
+ : HasExplicitConstructor<T, Args...>, NothrowDestructible<T>
+{ }
+
          
+
+
          
+We should then use ExplicitConstructible as the requirement for all
+emplace_xxx() member functions.
+
          
+
          
+For coherence and consistency with the similar concepts
+Convertible/ExplicitlyConvertible, we might also consider changing
+Constructible to:
+
          
+
+
          auto concept Constructible<typename T, typename... Args>
+ : HasConstructor<T, Args...>, ExplicitConstructible<T, Args...>
+{ }
+
          
+
+
          
+Moreover, all emplace-related concepts in  [container.concepts]
+should also use ExplicitConstructible instead of Constructible in the
+definitions of their axioms. In fact the concepts in  [container.concepts] should be
+corrected even if the issue is not accepted.
+
          
+
          
+On the other hand, if the issue is not accepted, the scoped allocator
+adaptors should be fixed because the following code:
+
          
+
+
          template <typename T> using scoped_allocator = scoped_allocator_adaptor<allocator<T>>;
+
+vector<shared_ptr<int>, scoped_allocator<shared_ptr<int>>> v;
+v.emplace_back(new int); // ops! doesn't compile
+
          
+
+
          
+doesn't compile, as the member function construct() of the scoped
+allocator requires non-explicit constructors through concept
+ConstructibleWithAllocator. Fixing that is not difficult but probably
+more work than it's worth and is therefore, IMHO, one more reason in
+support of the complete removal of scoped allocators.
+
          
+
          
+
+
          [
+2009-06-09 Alan adds:
+]
          
+
+
+
          
+
          
+I reopened this issue because I did not think that these National Body
+comments were adequately addressed by marking them NAD. My understanding
+is that something can be marked NAD if it is clearly a misunderstanding
+or trivial, but a substantive issue that has any technical merit
+requires a disposition that addresses the concerns.
+
          
+
          
+The notes in the NB comment list (US 65 & US 74.1) say that:
+
          
+
            
+
          1. 
+this issue has not introduced any new arguments not previously discussed,
+
            2. 
+
          2. 
+the vote (4-9-3) was not a consensus for removing scoped allocators,
+
            3. 
+
          3. 
+the issue is resolved by
+N2840.
+
            4. 
+
          
+
          
+My opinion is:
+
          
+
            
+
          1. 
+there are new arguments in both comments regarding concepts (which were
+not present in the library when the scoped allocator proposal was voted
+in),
+
            2. 
+
          2. 
+the vote was clearly not a consensus for removal, but just saying there
+was a vote does not provide a rationale,
+
            3. 
+
          3. 
+I do not believe that N2840 addresses these comments (although it does
+many other things and was voted in with strong approval).
+
            4. 
+
          
+
+
          
+My motivation to open the issue was to ensure that the NB comments were
+adequately addressed in a way that would not risk a "no" vote on our
+FCD. If there are responses to the technical concerns raised, then
+perhaps they should be recorded. If the members of the NB who authored
+the comments are satisfied with N2840 and the other disposition remarks
+in the comment list, then I am sure they will say so. In either case,
+this issue can be closed very quickly in Frankfurt, and hopefully will
+have helped make us more confident of approval with little effort. If in
+fact there is controversy, my thought is that it is better to know now
+rather than later so there is more time to deal with it.
+
          
+
          
+
+
          [
+2009-10 Santa Cruz:
+]
          
+
+
+
          
+NAD Editorial.  Addressed by
+N2982.
+
          
+
+
+
+
          Proposed resolution:
          
+
+
+
          Rationale:
          
+Scoped allocators have been revised significantly.
+
+
+
+
+
 
          
 
          1077. Nonesense tuple declarations
          
 
          Section: 20.5.2 [tuple.tuple] Status: NAD Editorial
@@ -26513,7 +34919,7 @@ template <class... UTypes>
 
 
          
 
          1078. DE-17: Remove class type_index
          
-
          Section: 18.7.2 [type.index] Status: NAD Concepts
+
          Section: 20.11 [type.index] Status: NAD Concepts
  Submitter: Doug Gregor Opened: 2009-03-20  Last modified: 2009-07-16
          
 
          View all issues with NAD Concepts status.
          
 
          Discussion:
          
@@ -26599,7 +35005,7 @@ needed for name() and before() to work.
 
        
 
        
 
-
        Remove section 18.7.2 [type.index]
        
+
        Remove section 20.11 [type.index]
        
 
 
 
@@ -26607,13 +35013,13 @@ needed for name() and before() to work.
 
 
        
 
        1080. Concept ArithmeticLike should provide explicit boolean  conversion
        
-
        Section: 20.2.13 [concept.arithmetic] Status: NAD Concepts
+
        Section: X [concept.arithmetic] Status: NAD Concepts
  Submitter: Daniel Krügler Opened: 2009-03-21  Last modified: 2009-07-15
        
 
        View all issues with NAD Concepts status.
        
 
        Discussion:
        
 
        
 Astonishingly, the current concept ArithmeticLike as specified in
-20.2.13 [concept.arithmetic] does not provide explicit conversion
+X [concept.arithmetic] does not provide explicit conversion
 to bool although this is a common property of arithmetic types
 (4.12 [conv.bool]). Recent proposals that introduced such types
 (integers of arbitrary precision,
@@ -26626,7 +35032,7 @@ via conversion to long long) also took care of such a feature.
 
        
 Adding such an explicit conversion associated function would also
 partly solve a currently invalid effects clause in library, which bases
-on this property, 24.2.6 [random.access.iterators]/2:
+on this property, 24.2.5 [random.access.iterators]/2:
 
        
 
        { difference_type m = n;
  if (m >= 0) while (m--) ++r;
@@ -26644,7 +35050,7 @@ longer supported existing implicit conversion from int to IntegralL
 
          
 
        1. 
 
          
-In 20.2.13 [concept.arithmetic], add to the list of less refined
+In X [concept.arithmetic], add to the list of less refined
 concepts one further concept:
 
          
 
@@ -26660,7 +35066,7 @@ concepts one further concept:
 
          2. 
 
        2. 
 
          
-In 24.2.6 [random.access.iterators]/2 change the current effects clause
+In 24.2.5 [random.access.iterators]/2 change the current effects clause
 as indicated [The proposed insertion fixes the problem that the previous
 implicit construction from integrals has been changed to an explicit
 constructor]:
@@ -26695,7 +35101,7 @@ Move to Review, pending input from concepts experts.
 
 
          Proposed resolution:
          
 
          
-In 20.2.13 [concept.arithmetic], add to the list of less refined
+In X [concept.arithmetic], add to the list of less refined
 concepts one further concept:
 
          
 
@@ -26819,7 +35225,7 @@ To be handled by Howard Hinnant, Dave Abrahams, Martin Sebor, PJ Plauger.
 
 
          
 
          1084. Response to UK 250
          
-
          Section: 24.2.4 [forward.iterators] Status: NAD Concepts
+
          Section: 24.2.3 [forward.iterators] Status: NAD Concepts
  Submitter: Howard Hinnant Opened: 2009-03-22  Last modified: 2009-07-16
          
 
          View all other issues in [forward.iterators].
          
 
          View all issues with NAD Concepts status.
          
@@ -26852,7 +35258,7 @@ Howard will open an issue.
 
          
 This issue cannot currently be resolved as suggested, because
 that would render auto-detection of the return type
-postincrement_result invalid, see 14.10.2.2 [concept.map.assoc]/4+5. The
+postincrement_result invalid, see  [concept.map.assoc]/4+5. The
 best fix would be to add a default type to that associated type, but
 unfortunately any default type will prevent auto-deduction of types of
 associated functions as quoted above. A corresponding core issue
@@ -26862,13 +35268,13 @@ is in preparation.
 
 
          Proposed resolution:
          
 
          [
-This wording assumes the acceptance of UK 251 / 1009.  Both
+This wording assumes the acceptance of UK 251 / 1009.  Both
 wordings change the same paragraphs.
 ]
          
 
 
 
          
-Change 24.2.4 [forward.iterators]:
+Change 24.2.3 [forward.iterators]:
 
          
 
 
          
@@ -26898,7 +35304,7 @@ Change 24.2.4 [forward.iterators]:
 
 
          
 
          1085. Response to UK 258
          
-
          Section: 24.2.5 [bidirectional.iterators] Status: NAD Concepts
+
          Section: 24.2.4 [bidirectional.iterators] Status: NAD Concepts
  Submitter: Howard Hinnant Opened: 2009-03-22  Last modified: 2009-07-16
          
 
          View all other issues in [bidirectional.iterators].
          
 
          View all issues with NAD Concepts status.
          
@@ -26938,7 +35344,7 @@ that would render auto-detection of the return type
 
          Proposed resolution:
          
 
 
          
-Change 24.2.5 [bidirectional.iterators]:
+Change 24.2.4 [bidirectional.iterators]:
 
          
 
 
          
@@ -26990,7 +35396,7 @@ We agree. To be handled by Howard, Martin and PJ.
 
 
          
 
          1087. Response to UK 301
          
-
          Section: 25.4.5 [alg.replace] Status: NAD Concepts
+
          Section: 25.3.5 [alg.replace] Status: NAD Concepts
  Submitter: Howard Hinnant Opened: 2009-03-22  Last modified: 2009-07-15
          
 
          View all other issues in [alg.replace].
          
 
          View all issues with NAD Concepts status.
          
@@ -27021,7 +35427,7 @@ We agree. To be handled by Howard.
 
 
          Proposed resolution:
          
 
          
-Change in 25.2 [algorithms.syn] and 25.4.5 [alg.replace]:
+Change in  [algorithms.syn] and 25.3.5 [alg.replace]:
 
          
 
 
          template<ForwardIterator Iter, class T> 
@@ -27043,6 +35449,164 @@ template<ForwardIterator Iter, Predicate<auto, Iter::value_type> Pred,
 
 
 
+
          
+
          1088. Response to UK 342
          
+
          Section: 30.6.5 [futures.promise] Status: NAD Editorial
+ Submitter: Howard Hinnant Opened: 2009-03-22  Last modified: 2009-10-26
          
+
          View all other issues in [futures.promise].
          
+
          View all issues with NAD Editorial status.
          
+
          Discussion:
          
+
          Addresses UK 342
          
+
+
          
+std::promise is missing a non-member overload of swap. This is
+inconsistent with other types that provide a swap member function.
+
          
+
+
          
+Add a non-member overload void swap(promise&& x,promise&& y){ x.swap(y); }
+
          
+
+
          [
+Summit:
+]
          
+
+
          
+Create an issue. Move to review, attention: Howard. Detlef will also
+look into it.
+
          
+
+
          [
+Post Summit Daniel provided wording.
+]
          
+
+
+
          [
+2009-10 Santa Cruz:
+]
          
+
+
+
          
+NAD Editorial.  Solved by
+N2997.
+
          
+
+
+
+
          Proposed resolution:
          
+
            
+
          1. 
+
            
+In 30.6.5 [futures.promise], before p.1, immediately after class template
+promise add:
+
            
+
            
+template <class R>
+void swap(promise<R>& x, promise<R>& y);
+
+
            
+
            2. 
+
          2. 
+
            
+Change 30.6.5 [futures.promise]/10 as indicated (to fix a circular definition):
+
            
+
            
+
            
+-10- Effects: swap(*this, other)Swaps the associated state
+of *this and other
+
            
+
            
+Throws: Nothing.
+
            
+
            
+
            3. 
+
          3. 
+
            
+After the last paragraph in 30.6.5 [futures.promise] add the following
+prototype description:
+
            
+
            
+template <class R>
+void swap(promise<R>& x, promise<R>& y);
+
            
+
            
+
            
+Effects: x.swap(y)
+
            
+
            
+Throws: Nothing.
+
            
+
            
+
            
+
            4. 
+
+
          
+
+
+
+
+
+
+
          
+
          1091. Multimap description confusing
          
+
          Section: 23.4.2.2 [multimap.modifiers] Status: NAD
+ Submitter: LWG Opened: 2009-03-22  Last modified: 2009-10-20
          
+
          View all issues with NAD status.
          
+
          Discussion:
          
+
+
          Addresses UK 246
          
+
          
+The content of this sub-clause is purely trying to describe in words the
+effect of the requires clauses on these operations, now that we have
+Concepts. As such, the description is more confusing than the signature
+itself. The semantic for these functions is adequately covered in the
+requirements tables in 23.2.4 [associative.reqmts].
+
          
+
+
          [
+Beman adds:
+]
          
+
+
+
          
+Pete is clearly right that
+this one is technical rather than editorial.
+
          
+
+
          [
+Batavia (2009-05):
+]
          
+
+
          
+
          
+We agree with the proposed resolution.
+
          
+
          
+Move to Review.
+
          
+
          
+
+
          [
+2009-10 Santa Cruz:
+]
          
+
+
+
          
+Mark as NAD, solved by removing concepts.
+
          
+
+
+
+
          Proposed resolution:
          
+
          
+Strike 23.4.2.2 [multimap.modifiers] entirely
+(but do NOT strike these signatures from the class template definition!).
+
          
+
+
+
+
+
 
          
 
          1092. Class template integral_constant should be a  constrained template
          
 
          Section: 20.6.3 [meta.help] Status: NAD Concepts
@@ -27056,7 +35620,7 @@ constrain their common base template integral_constant. This can be don
 without enforcing depending classes to be constrained as well, but not
 vice versa
 without brute force late_check usages. The following proposed resolution depends
-on the resolution of LWG issue 1019.
+on the resolution of LWG issue 1019.
 
          
 
 
          [
@@ -27141,7 +35705,7 @@ Move to Open, pending proposed wording from Dave for further review.
 
 
          
 
          1101. unique requirements
          
-
          Section: 25.4.9 [alg.unique] Status: NAD Editorial
+
          Section: 25.3.9 [alg.unique] Status: NAD Editorial
  Submitter: Howard Hinnant Opened: 2009-04-25  Last modified: 2009-07-13
          
 
          View all other issues in [alg.unique].
          
 
          View all issues with NAD Editorial status.
          
@@ -27187,7 +35751,7 @@ Move to NAD Editorial.
 
 
          Proposed resolution:
          
 
          
-Change 25.4.9 [alg.unique]:
+Change 25.3.9 [alg.unique]:
 
          
 
 
          template<ForwardIterator Iter> 
@@ -27202,7 +35766,7 @@ template<ForwardIterator Iter, EquivalenceRelation<auto, Iter::value_type&
 
          
 
 
          
-Note that the synopsis in 25.2 [algorithms.syn] is already correct.
+Note that the synopsis in  [algorithms.syn] is already correct.
 
          
 
 
@@ -27210,9 +35774,146 @@ Note that the synopsis in 25.2 [algorithms.syn] is already correct.
 
 
 
+
          
+
          1102. std::vector's reallocation policy still unclear
          
+
          Section: 23.3.6.2 [vector.capacity] Status: NAD
+ Submitter: Daniel Krügler Opened: 2009-04-20  Last modified: 2009-10-20
          
+
          View all other issues in [vector.capacity].
          
+
          View all issues with NAD status.
          
+
          Discussion:
          
+
          
+I have the impression that even the wording of current draft
+N2857
+does insufficiently express the intent of vector's
+reallocation strategy. This has produced not too old library
+implementations which release memory in the clear() function
+and even modern articles about C++ programming cultivate
+the belief that clear is allowed to do exactly this. A typical
+example is something like this:
+
          
+
+
          const int buf_size = ...;
+std::vector<T> buf(buf_size);
+for (int i = 0; i < some_condition; ++i) {
+  buf.resize(buf_size);
+  write_or_read_data(buf.data());
+  buf.clear(); // Ensure that the next round get's 'zeroed' elements
+}
+
          
+
          
+where still the myth is ubiquitous that buf might be
+allowed to reallocate it's memory *inside* the for loop.
+
          
+
          
+IMO the problem is due to the fact, that
+
          
+
+
            
+
          1. 
+the actual memory-reallocation stability of std::vector
+is explained in 23.3.6.2 [vector.capacity]/3 and /6 which
+are describing just the effects of the reserve
+function, but in many examples (like above) there
+is no explicit call to reserve involved. Further-more
+23.3.6.2 [vector.capacity]/6 does only mention insertions
+and never mentions the consequences of erasing
+elements.
+
            2. 
+
          2. 
+
            
+the effects clause of std::vector's erase overloads in
+23.3.6.4 [vector.modifiers]/4 is silent about capacity changes. This
+easily causes a misunderstanding, because the counter
+parting insert functions described in 23.3.6.4 [vector.modifiers]/2
+explicitly say, that
+
            
+
            
+Causes reallocation if the new size is greater than the
+old capacity. If no reallocation happens, all the iterators
+and references before the insertion point remain valid.
+
            
+
            
+It requires a complex argumentation chain about four
+different places in the standard to provide the - possibly
+weak - proof that calling clear() also does never change
+the capacity of the std::vector container. Since std::vector
+is the de-facto replacement of C99's dynamic arrays this
+type is near to a built-in type and it's specification should
+be clear enough that usual programmers can trust their
+own reading.
+
            
+
            3. 
+
          
+
+
          [
+Batavia (2009-05):
+]
          
+
+
          
+
          
+Bill believes paragraph 1 of the proposed resolution is unnecessary
+because it is already implied (even if tortuously) by the current wording.
+
          
+
          
+Move to Review.
+
          
+
          
+
+
          [
+2009-10 Santa Cruz:
+]
          
+
+
+
          
+Mark as NAD. Rationale: there is no consensus to clarify the standard,
+general consensus that the standard is correct as written.
+
          
+
+
+
+
          Proposed resolution:
          
+
          [
+This is a minimum version. I also
+suggest that the wording explaining the allocation strategy
+of std::vector in 23.3.6.2 [vector.capacity]/3 and /6 is moved into
+a separate sub paragraph of 23.3.6.2 [vector.capacity] before
+any of the prototype's are discussed, but I cannot provide
+reasonable wording changes now
+]
          
+
+
+
            
+
          1. 
+
            
+Change 23.3.6.2 [vector.capacity]/6 as follows:
+
            
+
            
+It is guaranteed that no reallocation takes place during
+insertions or erasures that happen after a call
+to reserve() until the time when an insertion would make
+the size of the vector greater than the value of capacity().
+
            
+
            2. 
+
          2. 
+
            
+Change 23.3.6.4 [vector.modifiers]/4 as follows:
+
            
+
            
+Effects: The capacity shall remain unchanged and no reallocation shall
+happen.
+Invalidates iterators and references at or after the point
+of the erase.
+
            
+
            3. 
+
          
+
+
+
+
+
 
          
 
          1105. Shouldn't Range be an auto concept
          
-
          Section: 24.2.8 [iterator.concepts.range] Status: NAD Concepts
+
          Section: X [iterator.concepts.range] Status: NAD Concepts
  Submitter: David Abrahams Opened: 2009-04-23  Last modified: 2009-07-15
          
 
          View all issues with NAD Concepts status.
          
 
          Discussion:
          
@@ -27319,14 +36020,13 @@ Committee Draft is issued.
 
 
          
 
          1107. constructor shared_future(unique_future) by value?
          
-
          Section: 30.6.6 [future.shared_future] Status: NAD Editorial
+
          Section: 30.6.7 [future.shared_future] Status: NAD Editorial
  Submitter: Thomas J. Gritzan Opened: 2009-04-03  Last modified: 2009-07-13
          
-
          View other active issues in [future.shared_future].
          
 
          View all other issues in [future.shared_future].
          
 
          View all issues with NAD Editorial status.
          
 
          Discussion:
          
 
          
-In the shared_future class definition in 30.6.6 [future.shared_future]
+In the shared_future class definition in 30.6.7 [future.shared_future]
 the move constructor 
 that constructs a shared_future from an unique_future receives the 
 parameter by value. In paragraph 3, the same constructor receives it as 
@@ -27367,14 +36067,14 @@ The proposed change has already been incorported into the current working draft
 
 
          Proposed resolution:
          
 
          
-Change the synopsis in 30.6.6 [future.shared_future]:
+Change the synopsis in 30.6.7 [future.shared_future]:
 
          
 
 
          shared_future(unique_future<R>&& rhs);
 
          
 
 
          
-Change the definition of the constructor in 30.6.6 [future.shared_future]:
+Change the definition of the constructor in 30.6.7 [future.shared_future]:
 
          
 
 
          shared_future(const unique_future<R>&& rhs);
@@ -27387,7 +36087,7 @@ Change the definition of the constructor in 30.6.6 [future.shared_future]:
 
 
          
 
          1109. std::includes should require CopyConstructible predicate
          
-
          Section: 25.5.5.1 [includes] Status: NAD Concepts
+
          Section: 25.4.5.1 [includes] Status: NAD Concepts
  Submitter: Alisdair Meredith Opened: 2009-04-28  Last modified: 2009-07-13
          
 
          View all other issues in [includes].
          
 
          View all issues with NAD Concepts status.
          
@@ -27411,7 +36111,7 @@ Move to NAD Editorial.
 
 
          Proposed resolution:
          
 
          
-Change 25.2 [algorithms.syn] and 25.5.5.1 [includes]:
+Change  [algorithms.syn] and 25.4.5.1 [includes]:
 
          
 
 
          template<InputIterator Iter1, InputIterator Iter2,
@@ -27789,9 +36489,256 @@ Associative containers 23.4 [associative]
 
 
 
+
          
+
          1116. Literal constructors for tuple
          
+
          Section: 20.5.2 [tuple.tuple] Status: NAD Editorial
+ Submitter: Alisdair Meredith Opened: 2009-05-23  Last modified: 2009-10-26
          
+
          View all other issues in [tuple.tuple].
          
+
          View all issues with NAD Editorial status.
          
+
          Discussion:
          
+
          
+It is not currently possible to construct tuple literal values,
+even if the elements are all literal types.  This is because parameters
+are passed to constructor by reference.
+
          
+
          
+An alternative would be to pass all constructor arguments by value, where it
+is known that *all* elements are literal types.  This can be determined with
+concepts, although note that the negative constraint really requires
+factoring out a separate concept, as there is no way to provide an 'any of
+these fails' constraint inline.
+
          
+
          
+Note that we will have similar issues with pair (and
+tuple constructors from pair) although I am steering
+clear of that class while other constructor-related issues settle.
+
          
+
+
          [
+2009-10 Santa Cruz:
+]
          
+
+
+
          
+NAD Editorial.  Solved by
+N2994.
+
          
+
+
+
          Proposed resolution:
          
+
          
+Ammend the tuple class template declaration in 20.5.2 [tuple.tuple] as
+follows
+
          
+
+
          
+
          
+Add the following concept:
+
          
+
+
          auto concept AllLiteral< typename ... Types > {
+  requires LiteralType<Types>...;
+}
+
          
+
+
          
+ammend the constructor 
+
          
+
+
          template <class... UTypes>
+  requires AllLiteral<Types...>
+        && Constructible<Types, UTypes>...
+  explicit tuple(UTypes...);
+
+template <class... UTypes>
+  requires !AllLiteral<Types...>
+        && Constructible<Types, UTypes&&>...
+  explicit tuple(UTypes&&...);
+
          
+
+
          
+ammend the constructor
+
          
+
+
          template <class... UTypes>
+  requires AllLiteral<Types...>
+        && Constructible<Types, UTypes>...
+  tuple(tuple<UTypes...>);
+
+template <class... UTypes>
+  requires !AllLiteral<Types...>
+        && Constructible<Types, const UTypes&>...
+  tuple(const tuple<UTypes...>&);
+
          
+
+
          
+
+
          
+Update the same signatures in 20.5.2.1 [tuple.cnstr], paras 3 and 5.
+
          
+
+
+
+
+
+
          
+
          1117. tuple copy constructor
          
+
          Section: 20.5.2.1 [tuple.cnstr] Status: NAD Editorial
+ Submitter: Alisdair Meredith Opened: 2009-05-23  Last modified: 2009-10-26
          
+
          View all other issues in [tuple.cnstr].
          
+
          View all issues with NAD Editorial status.
          
+
          Discussion:
          
+
          
+The copy constructor for the tuple template is constrained.  This seems an
+unusual strategy, as the copy constructor will be implicitly deleted if the
+constraints are not met.  This is exactly the same effect as requesting an
+=default; constructor.  The advantage of the latter is that it retains
+triviality, and provides support for tuples as literal types if issue
+1116 is also accepted.
+
          
+
          
+Actually, it might be worth checking with core if a constrained copy
+constructor is treated as a constructor template, and as such does not
+suppress the implicit generation of the copy constructor which would hide
+the template in this case.
+
          
+
+
          [
+2009-05-27 Daniel adds:
+]
          
+
+
+
          
+This would solve one half of the suggested changes in 801.
+
          
+
+
          [
+2009-10 Santa Cruz:
+]
          
+
+
+
          
+NAD Editorial.  Solved by
+N2994.
+
          
+
+
+
          Proposed resolution:
          
+
          
+Change 20.5.2 [tuple.tuple] and 20.5.2.1 [tuple.cnstr] p4:
+
          
+
+
          requires CopyConstructible<Types>... tuple(const tuple&) = default;
+
          
+
+
+
+
+
+
          
+
          1120. New type trait - remove_all
          
+
          Section: 20.6 [meta] Status: NAD Future
+ Submitter: Alisdair Meredith Opened: 2009-05-23  Last modified: 2009-10-26
          
+
          View all other issues in [meta].
          
+
          View all issues with NAD Future status.
          
+
          Discussion:
          
+
          
+Sometimes it is necessary to remove all qualifiers from a type before
+passing on to a further API.  A good example would be calling the
+tuple query APIs tuple_size or tuple_element
+with a deduced type inside a function template.  If the deduced type is
+cv-qualified or a reference then the call will fail.  The solution is to
+chain calls to
+remove_cv<remove_reference<T>::type>::type, and
+note that the order matters.
+
          
+
          
+Suggest it would be helpful to add a new type trait,
+remove_all, that removes all top-level qualifiers from a type
+i.e. cv-qualification and any references.  Define the term in such a way
+that if additional qualifiers are added to the language, then
+remove_all is defined as stripping those as well.
+
          
+
+
          [
+2009-10-14 Daniel adds:
+]
          
+
+
+
          
+remove_all seems too generic, a possible alternative matching
+the current naming style could be remove_cv_reference or
+remove_reference_cv. It should also be considered whether this
+trait should also remove 'extents', or pointer 'decorations'. Especially
+if the latter situations are considered as well, it might be easier to
+chose the name not in terms of what it removes (which might be
+a lot), but in terms of it creates. In this case I could think
+of e.g. extract_value_type.
+
          
+
+
          [
+2009-10 Santa Cruz:
+]
          
+
+
+
          
+NAD Future.
+
          
+
+
+
+
          Proposed resolution:
          
+
+
+
+
+
+
          
+
          1122. Ratio values should be constexpr
          
+
          Section: 20.4.1 [ratio.ratio] Status: NAD Editorial
+ Submitter: Alisdair Meredith Opened: 2009-05-25  Last modified: 2009-10-26
          
+
          View all other issues in [ratio.ratio].
          
+
          View all issues with NAD Editorial status.
          
+
          Discussion:
          
+
          
+The values num and den in the ratio template
+should be declared constexpr.
+
          
+
+
          [
+2009-10 Santa Cruz:
+]
          
+
+
+
          
+NAD Editorial.  Solved by
+N2994.
+
          
+
+
+
          Proposed resolution:
          
+
          
+20.4.1 [ratio.ratio]
+
          
+
+
          namespace std {
+  template <intmax_t N, intmax_t D = 1>
+  class ratio {
+  public:
+    static constexpr intmax_t num;
+    static constexpr intmax_t den;
+  };
+}
+
          
+
+
+
+
+
+
 
          
 
          1124.  Invalid definition of concept RvalueOf
          
-
          Section: 20.2.1 [concept.transform] Status: NAD Concepts
+
          Section: X [concept.transform] Status: NAD Concepts
  Submitter: Daniel Krügler Opened: 2009-05-28  Last modified: 2009-07-15
          
 
          View all other issues in [concept.transform].
          
 
          View all issues with NAD Concepts status.
          
@@ -27804,7 +36751,7 @@ specification of reference-related concepts.
 
          
 
          
 One problem of the concept RvalueOf as currently defined in
-20.2.1 [concept.transform]:
+X [concept.transform]:
 
          
 
 
          concept RvalueOf<typename T> {
@@ -27832,7 +36779,7 @@ type requirement.
 
 
          Proposed resolution:
          
 
          
-In 20.2.1 [concept.transform] before p. 4 change as indicated:
+In X [concept.transform] before p. 4 change as indicated:
 
          
 
 
          auto concept RvalueOf<typename T> {
@@ -27847,7 +36794,7 @@ In 20.2.1 [concept.transform] before p. 4 change as indicated:
 
 
          
 
          1127. rvalue references and iterator traits
          
-
          Section: D.10.1 [iterator.traits] Status: NAD Concepts
+
          Section: 24.4.1 [iterator.traits] Status: NAD Concepts
  Submitter: Alisdair Meredith Opened: 2009-05-28  Last modified: 2009-07-15
          
 
          View all other issues in [iterator.traits].
          
 
          View all issues with NAD Concepts status.
          
@@ -27878,7 +36825,7 @@ fuller investigation of type_trait/concept unification though.
 
 
          Proposed resolution:
          
 
          
-In Iterator traits D.10.1 [iterator.traits] para 4 add:
+In Iterator traits 24.4.1 [iterator.traits] para 4 add:
 
          
 
 
          concept IsReference<typename T> { } // exposition only
@@ -27893,13 +36840,13 @@ template<typename T> concept_map IsReference<T&> { }
 
 
          
 
          1128. Missing definition of iterator_traits<T*>
          
-
          Section: 24.3 [iterator.syn] Status: NAD Concepts
+
          Section: X [iterator.syn] Status: NAD Concepts
  Submitter: Alisdair Meredith Opened: 2009-05-28  Last modified: 2009-07-16
          
 
          View all issues with NAD Concepts status.
          
 
          Discussion:
          
 
          
 The <iterator> header synopsis declares a partial specialization of
-iterator_traits to support pointers, 24.3 [iterator.syn].  The implication
+iterator_traits to support pointers, X [iterator.syn].  The implication
 is that specialization will be described in D10, yet it did not follow the
 rest of the deprecated material into this clause.
 
          
@@ -27935,7 +36882,7 @@ standards.  This is probably a matter best left to the Editor though.
 
 
          Proposed resolution:
          
 
          
-In 24.3 [iterator.syn] strike:
+In X [iterator.syn] strike:
 
          
 
 
          template<class T> struct iterator_traits<T*>;
@@ -27946,6 +36893,402 @@ In 24.3 [iterator.syn] strike:
 
 
 
+
          
+
          1129. istream(buf)_iterator should support literal sentinel value
          
+
          Section: 24.6.1.1 [istream.iterator.cons], 24.6.3 [istreambuf.iterator] Status: NAD Editorial
+ Submitter: Alisdair Meredith Opened: 2009-05-30  Last modified: 2009-10-26
          
+
          View all issues with NAD Editorial status.
          
+
          Discussion:
          
+
          
+istream_iterator and istreambuf_iterator should support literal sentinel
+values.  The default constructor is frequently used to terminate ranges, and
+could easily be a literal value for istreambuf_iterator, and
+istream_iterator when iterating value types.  A little more work using a
+suitably sized/aligned char-array for storage (or an updated component like
+boost::optional proposed for TR2) would allow istream_iterator to support
+constexpr default constructor in all cases, although we might leave this
+tweak as a QoI issue.  Note that requiring constexpr be supported also
+allows us to place no-throw guarantees on this constructor too.
+
          
+
+
          [
+2009-06-02 Daniel adds:
+]
          
+
+
+
          
+
          
+I agree with the usefulness of the issue suggestion, but we need
+to ensure that istream_iterator can satisfy be literal if needed.
+Currently this is not clear, because 24.6.1 [istream.iterator]/3 declares
+a copy constructor and a destructor and explains their semantic in
+24.6.1.1 [istream.iterator.cons]/3+4.
+
          
+
          
+The prototype semantic specification is ok (although it seems
+somewhat redundant to me, because the semantic doesn't say
+anything interesting in both cases), but for support of trivial class
+types we also need a trivial copy constructor and destructor as of
+9 [class]/6. The current non-informative specification of these
+two special members suggests to remove their explicit declaration
+in the class and add explicit wording that says that if T is
+trivial a default constructed iterator is also literal, alternatively it
+would be possible to mark both as defaulted and add explicit
+(memberwise) wording that guarantees that they are trivial.
+
          
+
          
+Btw.: I'm quite sure that the istreambuf_iterator additions to
+ensure triviality are not sufficient as suggested, because the
+library does not yet give general guarantees that a defaulted
+special member declaration makes this member also trivial.
+Note that e.g. the atomic types do give a general statement!
+
          
+
          
+Finally there is a wording issue: There does not exist something
+like a "literal constructor". The core language uses the term
+"constexpr constructor" for this.
+
          
+
          
+Suggestion:
+
          
+
            
+
          1. 
+
            
+Change 24.6.1 [istream.iterator]/3 as indicated:
+
            
+
            constexpr istream_iterator();
+istream_iterator(istream_type& s);
+istream_iterator(const istream_iterator<T,charT,traits,Distance>& x) = default;
+~istream_iterator() = default;
+
            
+
            2. 
+
          2. 
+
            
+Change 24.6.1.1 [istream.iterator.cons]/1 as indicated:
+
            
+
            constexpr istream_iterator();
+
            
+
            
+-1- Effects: Constructs the end-of-stream iterator. If T is a literal type,
+then this constructor shall be a constexpr constructor.
+
            
+
            
+
            3. 
+
          3. 
+
            
+Change 24.6.1.1 [istream.iterator.cons]/3 as indicated:
+
            
+
            istream_iterator(const istream_iterator<T,charT,traits,Distance>& x) = default;
+
            
+
            
+-3- Effects: Constructs a copy of x. If T is a literal type, then
+this constructor shall be a trivial copy constructor.
+
            
+
            
+
            4. 
+
          4. 
+
            
+Change 24.6.1.1 [istream.iterator.cons]/4 as indicated:
+
            
+
+
            ~istream_iterator() = default;
+
            
+
            
+-4- Effects: The iterator is destroyed. If T is a literal type, then
+this destructor shall be a trivial
+destructor.
+
            
+
            
+
            5. 
+
          5. 
+
            
+Change 24.6.3 [istreambuf.iterator] before p. 1 as indicated:
+
            
+
+
            constexpr istreambuf_iterator() throw();
+istreambuf_iterator(const istreambuf_iterator&)  throw() = default;
+~istreambuf_iterator()  throw() = default;
+
            
+
            6. 
+
          6. 
+
            
+Change 24.6.3 [istreambuf.iterator]/1 as indicated:
+
            
+
            
+[..] The default constructor istreambuf_iterator() and the constructor
+istreambuf_iterator(0) both
+construct an end of stream iterator object suitable for use as an
+end-of-range. All
+specializations of istreambuf_iterator shall have a trivial copy
+constructor, a constexpr default
+constructor and a trivial destructor.
+
            
+
            7. 
+
          
+
          
+
+
          [
+2009-10 Santa Cruz:
+]
          
+
+
+
          
+NAD Editorial.  Solved by
+N2994.
+
          
+
+
+
+
          Proposed resolution:
          
+
          
+24.6.1 [istream.iterator] para 3
+
          
+
+
          constexpr istream_iterator();
+
          
+
+
          
+24.6.1.1 [istream.iterator.cons]
+
          
+
+
          constexpr istream_iterator();
+
          
+
          
+-1- Effects: Constructs the end-of-stream iterator.
+If T is a literal type, then this constructor shall
+be a literal constructor.
+
          
+
          
+
+
          
+24.6.3 [istreambuf.iterator]
+
          
+
+
          constexpr istreambuf_iterator() throw();
+
          
+
+
+
+
+
+
+
          
+
          1132. JP-30: nested exceptions
          
+
          Section: 18.8.6 [except.nested] Status: NAD
+ Submitter: Seiji Hayashida Opened: 2009-06-01  Last modified: 2009-10-23
          
+
          View other active issues in [except.nested].
          
+
          View all other issues in [except.nested].
          
+
          View all issues with NAD status.
          
+
          Discussion:
          
+
          Addresses JP 30
          
+
+
          
+C++0x nested_exception cannot handle a structured exception well. The
+following codes show two types of tree structured exception handling.
+
          
+
          
+The first one is based on nested_exception in C++0x,
+while the second one is based on my library trickerr.h (in Japanese).
+http://tricklib.com/cxx/dagger/trickerr.h
+
          
+
          
+Assume that Function A() calls two sub functions A_a() and A_b(), both might
+throw tree structured exceptions, and A_b() must be called even if A_a()
+throws an exception.
+
          
+
          
+List A (code of tree structured exception handling based on nested_exception
+in C++0x)
+
          
+
+
          void A()
+{
+    try
+    {
+        std::vector<exception_ptr> exception_list;
+        try
+        {
+            // A_a() does a similar processing as A().
+            A_a();
+        }
+        catch(...)
+        {
+            exception_list.push_back(current_exception());
+        }
+
+        // ***The processing A() has to do even when A_a() fails. ***
+        try
+        {
+            // A_b() does a similar processing as A().
+            A_b();
+        }
+        catch(...)
+        {
+            exception_list.push_back(current_exception());
+        }
+        if (!exception_list.empty())
+        {
+            throw exception_list;
+        }
+    }
+    catch(...)
+    {
+        throw_with_nested(A_exception("someone error"));
+    }
+}
+void print_tree_exception(exception_ptr e, const std::string & indent ="")
+{
+    const char * indent_unit = " ";
+    const char * mark = "- ";
+    try
+    {
+        rethow_exception(e);
+    }
+    catch(const std::vector<exception_ptr> e)
+    {
+        for(std::vector<exception_ptr>::const_iterator i = e.begin(); i!=e.end(); ++i)
+        {
+            print_tree_exception(i, indent);
+        }
+    }
+    catch(const std::nested_exception  e)
+    {
+        print_tree_exception(evil_i(e), indent +indent_unit);
+    }
+    catch(const std::exception e)
+    {
+        std::cout << indent << mark << e.what() << std::endl;
+    }
+    catch(...)
+    {
+        std::cout << indent << mark << "unknown exception" << std::endl;
+    }
+}
+int main(int, char * [])
+{
+    try
+    {
+        A();
+    }
+    catch()
+    {
+        print_tree_exception(current_exception());
+    }
+    return EXIT_SUCCESS;
+}
+
          
+
+
          
+List B ( code of tree structured exception handling based on trickerr.h. )
+"trickerr.h" (in Japanese), refer to:
+http://tricklib.com/cxx/dagger/trickerr.h.
+
          
+
+
          void A()
+{
+    tricklib::error_listener_type error_listener;
+    // A_a() is like A(). A_a() can throw tree structured exception.
+    A_a();
+
+    // *** It must do process so that A_a() throws exception in A(). ***
+    // A_b() is like A(). A_b() can throw tree structured exception.
+    A_b();
+
+    if (error_listener.has_error()) // You can write this "if block" in destructor
+                                    //  of class derived from error_listener_type.
+    {
+        throw_error(new A_error("someone error",error_listener.listener_off().extract_pending_error()));
+    }
+}
+void print_tree_error(const tricklib::error_type &a_error, const std::string & indent = "")
+{
+    const char * indent_unit = " ";
+    const char * mark = "- ";
+
+    tricklib::error_type error = a_error;
+    while(error)
+    {
+        std::cout << indent << mark << error->message << std::endl;
+        if (error->children)
+        {
+            print_tree_error(error->children, indent +indent_unit);
+        }
+        error = error->next;
+    }
+}
+int main(int, char * [])
+{
+    tricklib::error_thread_power error_thread_power_on; // This object is necessary per thread.
+
+    try
+    {
+        A();
+    }
+    catch(error_type error)
+    {
+        print_tree_error(error);
+    }
+    catch(...)
+    {
+        std::cout << "- unknown exception" << std::endl;
+    }
+    return EXIT_SUCCESS;
+}
+
          
+
+
          
+Prospect
+
          
+
          
+We will focus on the method A() since the other methods, also main(), occur
+only once respectively.
+
          
+
+
            
+
          • 
+ In the List A above (of the nested exception handling), it is hard to
+ find out an active reason to use the nested exception handling at this
+ scene. Rather, we can take a simpler description by throwing the entire
+ exception_list directly to the top level.
+
            • 
+
          • 
+ The code in the same example gives us a kind of redundant impression,
+ which might have come from the fact that the try-throw-catch framework does
+ not assume a tree structured exception handling.
+
            • 
+
          
+
+
          
+According to the above observation, we cannot help concluding that it is not
+so easy to use the nested_exception handling as a tree structured exception
+handling mechanism in a practical sense.
+
          
+
          
+This text is based on the web page below (in Japanese).
+http://d.hatena.ne.jp/wraith13/20081231/1230715424
+
          
+
+
          [
+2009-10 Santa Cruz:
+]
          
+
+
+
          
+Mark as NAD. The committee agrees that nested_exception is not a good
+match for this usage model. The committee did not see a way of improving
+this within the timeframe allowed.
+
          
+
+
+
+
          Proposed resolution:
          
+
          
+
          
+
+
+
+
+
 
          
 
          1139. Thread support library not concept enabled
          
 
          Section: 30 [thread] Status: NAD Concepts
@@ -28042,11 +37385,10 @@ The regular expressions chapter is not concept enabled.
 
 
          
 
          1143. Atomic operations library not concept enabled
          
-
          Section: 29 [atomics] Status: NAD Concepts
- Submitter: LWG Opened: 2009-06-15  Last modified: 2009-07-15
          
-
          View other active issues in [atomics].
          
+
          Section: 29 [atomics] Status: NAD Editorial
+ Submitter: LWG Opened: 2009-06-15  Last modified: 2009-10-26
          
 
          View all other issues in [atomics].
          
-
          View all issues with NAD Concepts status.
          
+
          View all issues with NAD Editorial status.
          
 
          Discussion:
          
 
 
          Addresses US 87, UK 311
          
@@ -28056,9 +37398,19 @@ The atomics chapter is not concept enabled.
 
          
 
 
          
-Needs to also consider issues 923 and 924.
+Needs to also consider issues 923 and 924.
 
          
 
+
          [
+2009-10 Santa Cruz:
+]
          
+
+
+
          
+NAD Editorial.  Solved by
+N2992.
+
          
+
 
 
 
          Proposed resolution:
          
@@ -28067,6 +37419,511 @@ Needs to also consider issues 1145. inappropriate headers for atomics
+
          Section: 29 [atomics] Status: NAD Editorial
+ Submitter: LWG Opened: 2009-06-16  Last modified: 2009-10-26
          
+
          View all other issues in [atomics].
          
+
          View all issues with NAD Editorial status.
          
+
          Discussion:
          
+
+
          Addresses UK 312
          
+
+
          
+The contents of the <stdatomic.h> header are not listed anywhere,
+and <cstdatomic> is listed as a C99 header in chapter 17.
+If we intend to use these for compatibility with a future C standard,
+we should not use them now.
+
          
+
+
          [
+2009-10 Santa Cruz:
+]
          
+
+
+
          
+NAD Editorial.  Solved by
+N2992.
+
          
+
+
+
+
          Proposed resolution:
          
+
          
+Remove <cstdatomic> from the C99 headers in table 14.
+Add a new header <atomic> to the headers in table 13.
+Update chapter 29 to remove reference to <stdatomic.h>
+and replace the use of <cstdatomic> with <atomic>.
+
          
+
          [
+If and when WG14 adds atomic operations to C
+we can add corresponding headers to table 14 with a TR.
+]
          
+
+
+
+
+
+
+
          
+
          1146. "lockfree" does not say enough
          
+
          Section: 29.4 [atomics.lockfree] Status: NAD Editorial
+ Submitter: Jeffrey Yasskin Opened: 2009-06-16  Last modified: 2009-10-26
          
+
          View all issues with NAD Editorial status.
          
+
          Discussion:
          
+
+
          Addresses US 88
          
+
+
          
+The "lockfree" facilities do not tell the programmer enough.
+
          
+
+
          
+There are 2 problems here.
+First, at least on x86,
+it's less important to me whether some integral types are lock free
+than what is the largest type I can pass to atomic and have it be lock-free.
+For example, if long longs are not lock-free,
+ATOMIC_INTEGRAL_LOCK_FREE is probably 1,
+but I'd still be interested in knowing whether longs are always lock-free.
+Or if long longs at any address are lock-free,
+I'd expect ATOMIC_INTEGRAL_LOCK_FREE to be 2,
+but I may actually care whether I have access to
+the cmpxchg16b instruction.
+None of the support here helps with that question.
+(There are really 2 related questions here:
+what alignment requirements are there for lock-free access;
+and what processor is the program actually running on,
+as opposed to what it was compiled for?)
+
          
+
+
          
+Second, having atomic_is_lock_free only apply to individual objects
+is pretty useless
+(except, as Lawrence Crowl points out,
+for throwing an exception when an object is unexpectedly not lock-free).
+I'm likely to want to use its result to decide what algorithm to use,
+and that algorithm is probably going to allocate new memory
+containing atomic objects and then try to act on them.
+If I can't predict the lock-freedom of the new object
+by checking the lock-freedom of an existing object,
+I may discover after starting the algorithm that I can't continue.
+
          
+
+
          [
+2009-06-16 Jeffrey Yasskin adds:
+]
          
+
+
+
          
+
          
+To solve the first problem, I think 2 macros would help:
+MAX_POSSIBLE_LOCK_FREE_SIZE and MAX_GUARANTEED_LOCK_FREE_SIZE,
+which expand to the maximum value of sizeof(T) for which atomic may
+(or will, respectively) use lock-free operations.
+Lawrence points out that this
+"relies heavily on implementations
+using word-size compare-swap on sub-word-size types,
+which in turn requires address modulation."
+He expects that to be the end state anyway, so it doesn't bother him much.
+
          
+
+
          
+To solve the second,
+I think one could specify that equally aligned objects of the same type
+will return the same value from atomic_is_lock_free().
+I don't know how to specify "equal alignment".
+Lawrence suggests an additional function, atomic_is_always_lock_free().
+
          
+
          
+
+
          [
+2009-10-22 Benjamin Kosnik:
+]
          
+
+
+
          
+
          
+In the evolution discussion of N2925, "More Collected Issues with
+Atomics," there is an action item with respect to
+LWG 1146, US 88
+
          
+
+
          
+This is stated in the paper as:
+
          
+
          
+Relatedly, Mike Sperts will create an issue to propose adding a traits
+mechanism to check the compile-time properties through a template
+mechanism rather than macros
+
          
+
+
          
+Here is my attempt to do this. I don't believe that a separate trait is
+necessary for this, and that instead atomic_integral::is_lock_free can
+be re-purposed with minimal work as follows.
+
          
+
+
          [
+Howard: Put Benjamin's wording in the proposed wording section.
+]
          
+
+
+
          
+
+
          [
+2009-10-22 Alberto Ganesh Barbati:
+]
          
+
+
+
          
+
          
+Just a thought... wouldn't it be better to use a scoped enum instead of
+plain integers? For example:
+
          
+
+
          enum class is_lock_free
+{
+    never = 0, sometimes = 1, always = 2;
+};
+
          
+
+
          
+if compatibility with C is deemed important, we could use an unscoped
+enum with suitably chosen names.  It would still be more descriptive
+than 0, 1 and 2.
+
          
+
+
          
+
+
          [
+2009-10 Santa Cruz:
+]
          
+
+
+
          
+NAD Editorial.  Solved by
+N2992.
+
          
+
+
+
+
          Proposed resolution:
          
+
          
+Header <cstdatomic> synopsis  [atomics.synopsis]
+
          
+
+
          
+Edit  as follows:
+
          
+
+
          namespace std {
+...
+// 29.4, lock-free property
+#define ATOMIC_INTEGRAL_LOCK_FREE unspecified
+#define ATOMIC_CHAR_LOCK_FREE unspecified
+#define ATOMIC_CHAR16_T_LOCK_FREE unspecified
+#define ATOMIC_CHAR32_T_LOCK_FREE unspecified
+#define ATOMIC_WCHAR_T_LOCK_FREE unspecified
+#define ATOMIC_SHORT_LOCK_FREE unspecified
+#define ATOMIC_INT_LOCK_FREE unspecified
+#define ATOMIC_LONG_LOCK_FREE unspecified
+#define ATOMIC_LLONG_LOCK_FREE unspecified
+#define ATOMIC_ADDRESS_LOCK_FREE unspecified
+
          
+
+
          
+Lock-free Property 29.4 [atomics.lockfree]
+
          
+
+
          
+Edit the synopsis as follows.
+
          
+
+
          namespace std {
+   #define ATOMIC_INTEGRAL_LOCK_FREE unspecified
+   #define ATOMIC_CHAR_LOCK_FREE unspecified
+   #define ATOMIC_CHAR16_T_LOCK_FREE unspecified
+   #define ATOMIC_CHAR32_T_LOCK_FREE unspecified
+   #define ATOMIC_WCHAR_T_LOCK_FREE unspecified
+   #define ATOMIC_SHORT_LOCK_FREE unspecified
+   #define ATOMIC_INT_LOCK_FREE unspecified
+   #define ATOMIC_LONG_LOCK_FREE unspecified
+   #define ATOMIC_LLONG_LOCK_FREE unspecified
+   #define ATOMIC_ADDRESS_LOCK_FREE unspecified
+}
+
          
+
+
          
+Edit paragraph 1 as follows.
+
          
+
+
          
+The ATOMIC_...._LOCK_FREE macros ATOMIC_INTEGRAL_LOCK_FREE and ATOMIC_ADDRESS_LOCK_FREE indicate the general lock-free
+property of integral and address atomic the corresponding atomic integral types, with the
+signed and unsigned variants grouped together.
+The properties also apply to the corresponding specializations of the atomic template.
+A value of 0
+indicates that the types are never lock-free. A value of 1
+indicates that the types are sometimes lock-free. A value of 2
+indicates that the types are always lock-free.
+
          
+
+
          
+Operations on Atomic Types 29.6 [atomics.types.operations]
+
          
+
+
          
+Edit as follows.
+
          
+
+
          void static constexpr bool A::is_lock_free() const volatile;
+
          
+
          
+Returns: True if the object's types's operations are lock-free, false
+otherwise.
+
+[Note: In the same way that <limits>
+std::numeric_limits<short>::max() is related to
+<limits.h> __LONG_LONG_MAX__, <atomic>
+std::atomic_short::is_lock_free is related to
+<stdatomic.h> and ATOMIC_SHORT_LOCK_FREE —
+end note]
+
+
          
+
          
+
+
+
+
+
+
+
          
+
          1147. non-volatile atomic functions
          
+
          Section: 29.6 [atomics.types.operations] Status: NAD Editorial
+ Submitter: Jeffrey Yasskin Opened: 2009-06-16  Last modified: 2009-10-26
          
+
          View all other issues in [atomics.types.operations].
          
+
          View all issues with NAD Editorial status.
          
+
          Discussion:
          
+
+
          Addresses US 90
          
+
+
          
+The C++0X draft
+declares all of the functions dealing with atomics (section 29.6 [atomics.types.operations])
+to take volatile arguments.
+Yet it also says (29.4-3),
+
          
+
+
          
+
          
+[ Note: Many operations are volatile-qualified.
+The "volatile as device register" semantics have not changed in the standard.
+This qualification means that volatility is preserved
+when applying these operations to volatile objects.
+It does not mean that operations on non-volatile objects become volatile.
+Thus, volatile qualified operations on non-volatile objects
+may be merged under some conditions. —end note ]
+
          
+
          
+
+
          
+I was thinking about how to implement this in gcc,
+and I believe that we'll want to overload most of the functions
+on volatile and non-volatile.
+Here's why:
+
          
+
+
          
+To let the compiler take advantage of the permission
+to merge non-volatile atomic operations and reorder atomics in certain,
+we'll need to tell the compiler backend
+about exactly which atomic operation was used.
+So I expect most of the functions of the form atomic_<op>_explicit()
+(e.g. atomic_load_explicit, atomic_exchange_explicit,
+atomic_fetch_add_explicit, etc.)
+to become compiler builtins.
+A builtin can tell whether its argument was volatile or not,
+so those functions don't really need extra explicit overloads.
+However, I don't expect that we'll want to add builtins
+for every function in chapter 29,
+since most can be implemented in terms of the _explicit free functions:
+
          
+
+
          class atomic_int {
+  __atomic_int_storage value;
+ public:
+  int fetch_add(int increment, memory_order order = memory_order_seq_cst) volatile {
+    // &value has type "volatile __atomic_int_storage*".
+    atomic_fetch_add_explicit(&value, increment, order);
+  }
+  ...
+};
+
          
+
+
          
+But now this always calls
+the volatile builtin version of atomic_fetch_add_explicit(),
+even if the atomic_int wasn't declared volatile.
+To preserve volatility and the compiler's permission to optimize,
+I'd need to write:
+
          
+
+
          class atomic_int {
+  __atomic_int_storage value;
+ public:
+  int fetch_add(int increment, memory_order order = memory_order_seq_cst) volatile {
+    atomic_fetch_add_explicit(&value, increment, order);
+  }
+  int fetch_add(int increment, memory_order order = memory_order_seq_cst) {
+    atomic_fetch_add_explicit(&value, increment, order);
+  }
+  ...
+};
+
          
+
+
          
+But this is visibly different from the declarations in the standard
+because it's now overloaded.
+(Consider passing &atomic_int::fetch_add as a template parameter.)
+
          
+
+
          
+The implementation may already have permission to add overloads
+to the member functions:
+
          
+
+
          
+
          
+17.6.4.5 [member.functions] An implementation may declare additional non-virtual
+member function signatures within a class:
          
+...
+
          
+
            
+
          • by adding a member function signature for a member function name.
            • 
+
          
+
          
+
+
          
+but I don't see an equivalent permission to add overloads to the free functions.
+
          
+
+
          [
+2009-06-16 Lawrence adds:
+]
          
+
+
+
          
+
          
+I recommend allowing non-volatile overloads.
+
          
+
          
+
+
          [
+2009-10 Santa Cruz:
+]
          
+
+
+
          
+NAD Editorial.  Solved by
+N2992.
+
          
+
+
+
+
          Proposed resolution:
          
+
+
+
+
+
+
          
+
          1148. Wrong argument type of I/O stream manipulators setprecision()
+and setw()
          
+
          Section: 27.7 [iostream.format] Status: NAD
+ Submitter: Marc Steinbach Opened: 2009-06-20  Last modified: 2009-10-20
          
+
          View all other issues in [iostream.format].
          
+
          View all issues with NAD status.
          
+
          Discussion:
          
+
          
+The header <iomanip> synopsis in 27.7 [iostream.format] specifies
+
          
+
          T5 setprecision(int n);
+T6 setw(int n);
+
          
+
+
          
+The argument types should be streamsize, as in class ios_base
+(see 27.5.2 [ios.base]):
+
          
+
          streamsize precision() const;
+streamsize precision(streamsize prec);
+streamsize width() const;
+streamsize width(streamsize wide);
+
          
+
+
          
+(Editorial: 'wide' should probably be renamed as 'width', or maybe just 'w'.)
+
          
+
+
          [
+2009-07-29 Daniel clarified wording.
+]
          
+
+
+
          [
+2009 Santa Cruz:
+]
          
+
+
+
          
+
          
+No concensus for this change.  There was some interest in doing the opposite
+fix:  Change the streamsize in <ios> to int.
+But ultimately there was no concensus for that change either.
+
          
+
          
+
+
+
+
          Proposed resolution:
          
+
            
+
          1. 
+
            
+In 27.7 [iostream.format], header <iomanip> synopsis change as indicated:
+
            
+
+
            T5 setprecision(intstreamsize n);
+T6 setw(intstreamsize n);
+
            
+
            2. 
+
+
          2. 
+
            
+In 27.7.3 [std.manip], just before p. 6 change as indicated:
+
            
+
+
            unspecified setprecision(intstreamsize n);
+
            
+
            3. 
+
+
          3. 
+
            
+In 27.7.3 [std.manip], just before p. 7 change as indicated:
+
            
+
+
            unspecified setw(intstreamsize n);
+
            
+
            4. 
+
          
+
+
+
+
+
+
+
+
 
          
 
          1149. Reformulating NonemptyRange axiom
          
 
          Section: 26.5.2.2 [rand.concept.urng] Status: NAD Concepts
@@ -28125,11 +37982,347 @@ In 26.5.2.2 [rand.concept.urng], replace the NonemptyRange axiom by:
 
 
 
+
          
+
          1150. wchar_t, char16_t and char32_t filenames
          
+
          Section: 27.9.1.14 [fstream] Status: NAD Future
+ Submitter: LWG Opened: 2009-06-28  Last modified: 2009-10-20
          
+
          View all issues with NAD Future status.
          
+
          Discussion:
          
+
          Addresses JP 73
          
+
+   
          Description
          
+        
          It is a problem
+        from C++98, fstream cannot appoint a filename of wide
+        character string(const wchar_t and const wstring&).
          
+
          Suggestion
          
+        
          Add
+        interface corresponding to wchar_t, char16_t and char32_t.
          
+
+
          [
+2009-07-01 Alisdair notes that this is a duplicate of 454 which has more
+in-depth rationale.
+]
          
+
+
+
          [
+2009-09-21 Daniel adds:
+]
          
+
+
+
          
+I suggest to mark this issue as NAD Future with the intend to
+solve the issue with a single file path c'tor template assuming
+a provision of a TR2 filesystem library.
+
          
+
+
          [
+2009 Santa Cruz:
+]
          
+
+
+
          
+NAD Future.  This is a duplicate of 454.
+
          
+
+
+
+
          Proposed resolution:
          
+
+
+
+
+
+
          
+
          1155. Reference should be to C99
          
+
          Section: C.2 [diff.library] Status: NAD Editorial
+ Submitter: LWG Opened: 2009-06-28  Last modified: 2009-10-23
          
+
          View all other issues in [diff.library].
          
+
          View all issues with NAD Editorial status.
          
+
          Discussion:
          
+
+
          Addresses FR 38
          
+
+
          Description
          
+        
          What is ISO/IEC 1990:9899/DAM
+        1? My guess is that's a typo for ISO/IEC
+        9899/Amd.1:1995 which I'd
+        have expected to be referenced here (the tables
+        make reference to things
+        which were introduced by Amd.1).
          
+
          Suggestion
          
+        
          One need probably a reference
+        to the document which introduce char16_t and
+        char32_t in C (ISO/IEC TR 19769:2004?).
          
+
          Notes
          
+
          Create issue. Document in question should be C99, not C90+amendment1. The 
+    rest of the section requires careful review for completeness. Example <cstdint> 
+    18.4.1 [cstdint.syn]. Assign to C liasons.
          
+
+
          [
+2009-10 Santa Cruz:
+]
          
+
+
+
          
+NAD Editorial. Already fixed.
+
          
+
+
+
+
          Proposed resolution:
          
+
+
+
+
+
+
          
+
          1160. future_error public constructor is 'exposition only'
          
+
          Section: 30.6.3 [futures.future_error] Status: NAD Editorial
+ Submitter: LWG Opened: 2009-06-28  Last modified: 2009-10-26
          
+
          View all issues with NAD Editorial status.
          
+
          Discussion:
          
+
+
          Addresses UK 331
          
+
+
          Description
          
+        
          Not clear what
+        it means for a public constructor to be 'exposition only'.
+        If the intent is purely to support the library calling this
+        constructor then it can be made private and accessed
+        through friendship. Otherwise it should be documented for
+        public consumption.
          
+
          Suggestion
          
+        
          Declare the constructor as private with a
+        note about intended friendship, or remove the
+        exposition-only comment and document the semantics.
          
+
          Notes
          
+
          Create an issue. Assigned to Detlef. Suggested resolution probably makes 
+    sense.
          
+
+
          [
+2009-07 Frankfurt
+]
          
+
+
+
          
+Pending a paper from Anthony Williams / Detleff Volleman.
+
          
+
+
          [
+2009-10-14 Pending paper:
+N2967.
+]
          
+
+
+
          [
+2009-10 Santa Cruz:
+]
          
+
+
+
          
+NAD Editorial.  Solved by
+N2997.
+
          
+
+
+
+
          Proposed resolution:
          
+
+
+
+
+
+
          
+
          1161. Unnecessary unique_future limitations
          
+
          Section: 30.6.6 [futures.unique_future] Status: NAD Editorial
+ Submitter: LWG Opened: 2009-06-28  Last modified: 2009-10-26
          
+
          View all other issues in [futures.unique_future].
          
+
          View all issues with NAD Editorial status.
          
+
          Discussion:
          
+
+
          Addresses UK 336
          
+
+
          Description
          
+
+        
          It is possible
+        to transfer ownership of the asynchronous result from one
+        unique_future instance to another via the move-constructor.
+        However, it is not possible to transfer it back, and nor is
+        it possible to create a default-constructed unique_future
+        instance to use as a later move target. This unduly limits
+        the use of unique_future in code. Also, the lack of a
+        move-assignment operator restricts the use of unique_future
+        in containers such as std::vector - vector::insert requires
+        move-assignable for example.
          
+
          Suggestion
          
+        
          Add a default constructor with the
+        semantics that it creates a unique_future with no
+        associated asynchronous result. Add a move-assignment
+        operator which transfers ownership.
          
+
          Notes
          
+
          Create an issue. Detlef will look into it.
          
+
+
          [
+2009-07 Frankfurt
+]
          
+
+
+
          
+Pending a paper from Anthony Williams / Detleff Volleman.
+
          
+
+
          [
+2009-10-14 Pending paper:
+N2967.
+]
          
+
+
+
          [
+2009-10 Santa Cruz:
+]
          
+
+
+
          
+NAD Editorial.  Solved by
+N2997.
+
          
+
+
+
+
          Proposed resolution:
          
+
+
+
+
+
+
          
+
          1162. shared_future should support an efficient move constructor
          
+
          Section: 30.6.7 [future.shared_future] Status: NAD Editorial
+ Submitter: LWG Opened: 2009-06-28  Last modified: 2009-10-26
          
+
          View all other issues in [future.shared_future].
          
+
          View all issues with NAD Editorial status.
          
+
          Discussion:
          
+
+
          Addresses UK 337
          
+
+
          Description
          
+        
          shared_future
+        should support an efficient move constructor that can avoid
+        unnecessary manipulation of a reference count, much like
+        shared_ptr
          
+
          Suggestion
          
+        
          Add a move constructor
          
+
          Notes
          
+
          Create an issue. Detlef will look into it.
          
+
+
          [
+2009-07 Frankfurt
+]
          
+
+
+
          
+Pending a paper from Anthony Williams / Detleff Volleman.
+
          
+
+
          [
+2009-10-14 Pending paper:
+N2967.
+]
          
+
+
+
          [
+2009-10 Santa Cruz:
+]
          
+
+
+
          
+NAD Editorial.  Solved by
+N2997.
+
          
+
+
+
+
          Proposed resolution:
          
+
+
+
+
+
+
          
+
          1163. shared_future is inconsistent with shared_ptr
          
+
          Section: 30.6.7 [future.shared_future] Status: NAD Editorial
+ Submitter: LWG Opened: 2009-06-28  Last modified: 2009-10-26
          
+
          View all other issues in [future.shared_future].
          
+
          View all issues with NAD Editorial status.
          
+
          Discussion:
          
+
+
          Addresses UK 338
          
+
+
          Description
          
+
+        
          shared_future is currently
+        CopyConstructible, but not CopyAssignable. This is
+        inconsistent with shared_ptr, and will surprise users.
+        Users will then write work-arounds to provide this
+        behaviour. We should provide it simply and efficiently as
+        part of shared_future. Note that since the shared_future
+        member functions for accessing the state are all declared
+        const, the original usage of an immutable shared_future
+        value that can be freely copied by multiple threads can be
+        retained by declaring such an instance as "const
+        shared_future".
          
+
          Suggestion
          
+        
          Remove "=delete"
+        from the copy-assignment operator of shared_future. Add a
+        move-constructor shared_future(shared_future&&
+        rhs), and a move-assignment operator shared_future&
+        operator=(shared_future&& rhs). The postcondition
+        for the copy-assignment operator is that *this has the same
+        associated state as rhs. The postcondition for the
+        move-constructor and move assignment is that *this has the
+        same associated as rhs had before the
+        constructor/assignment call and that rhs has no associated
+        state.
          
+
          Notes
          
+
          Create an issue. Detlef will look into it.
          
+
+
          [
+2009-07 Frankfurt
+]
          
+
+
+
          
+Pending a paper from Anthony Williams / Detleff Volleman.
+
          
+
+
          [
+2009-10-14 Pending paper:
+N2967.
+]
          
+
+
+
          [
+2009-10 Santa Cruz:
+]
          
+
+
+
          
+NAD Editorial.  Solved by
+N2997.
+
          
+
+
+
+
          Proposed resolution:
          
+
+
+
+
+
 
          
 
          1164. promise::swap should pass by rvalue reference
          
-
          Section: 30.6.4 [futures.promise] Status: NAD
+
          Section: 30.6.5 [futures.promise] Status: NAD
  Submitter: LWG Opened: 2009-06-28  Last modified: 2009-07-17
          
-
          View other active issues in [futures.promise].
          
 
          View all other issues in [futures.promise].
          
 
          View all issues with NAD status.
          
 
          Discussion:
          
@@ -28164,10 +38357,118 @@ NAD, by virtue of the changed rvalue rules and swap signatures from Summit.
 
 
 
+
          
+
          1165. Unneeded promise move constructor
          
+
          Section: 30.6.5 [futures.promise] Status: NAD Editorial
+ Submitter: LWG Opened: 2009-06-28  Last modified: 2009-10-26
          
+
          View all other issues in [futures.promise].
          
+
          View all issues with NAD Editorial status.
          
+
          Discussion:
          
+
+
          Addresses UK 343
          
+
+
          Description
          
+        
          The move constructor of a std::promise
+        object does not need to allocate any memory, so the
+        move-construct-with-allocator overload of the constructor
+        is superfluous.
          
+
          Suggestion
          
+        
          Remove the
+        constructor with the signature template <class
+        Allocator> promise(allocator_arg_t, const Allocator&
+        a, promise& rhs);
          
+
          Notes
          
+
          Create an issue. Detlef will look into it. Will solicit feedback from Pablo. 
+    Note that “rhs” argument should also be an rvalue reference in any case.
          
+
+
          [
+2009-07 Frankfurt
+]
          
+
+
+
          
+Pending a paper from Anthony Williams / Detleff Volleman.
+
          
+
+
          [
+2009-10 Santa Cruz:
+]
          
+
+
+
          
+NAD Editorial.  Solved by
+N2997.
+
          
+
+
+
+
          Proposed resolution:
          
+
+
+
+
+
+
          
+
          1166. Allocator-specific move/copy break model of move-constructor and
+        move-assignment
          
+
          Section: X [allocator.propagation], X [allocator.propagation.map], 23 [containers] Status: NAD Editorial
+ Submitter: LWG Opened: 2009-06-28  Last modified: 2009-10-26
          
+
          View all issues with NAD Editorial status.
          
+
          Discussion:
          
+
+
          Addresses US 77
          
+
+
          Description
          
+        
          Allocator-specific move and copy behavior for containers
+        (N2525) complicates a little-used and already-complicated
+        portion of the standard library (allocators), and breaks
+        the conceptual model of move-constructor and
+        move-assignment operations on standard containers being
+        efficient operations. The extensions for allocator-specific
+        move and copy behavior should be removed from the working
+        paper.
          
+        
          With the
+        introduction of rvalue references, we are teaching
+        programmers that moving from a standard container (e.g., a
+        vector<string>) is an efficient, constant-time
+        operation. The introduction of N2525 removed that
+        guarantee; depending on the behavior of four different
+        traits (20.8.4), the complexity of copy and move operations
+        can be constant or linear time. This level of customization
+        greatly increases the complexity of standard containers,
+        and benefits only a tiny fraction of the C++ community.
          
+
          Suggestion
          
+
+        
          Remove 20.8.4.
          
+        
+        
          Remove 20.8.5.
          
+        
+        
          Remove all references to the facilities in
+        20.8.4 and 20.8.5 from clause 23.
          
+
+
+
          [
+2009-10 Santa Cruz:
+]
          
+
+
+
          
+NAD Editorial.  Addressed by
+N2982.
+
          
+
+
+
+
          Proposed resolution:
          
+
+
+
+
+
 
          
 
          1167. pair<T,U> doesn't model LessThanComparable in unconstrained code even if
       T and U do.
          
-
          Section: 20.3.3 [pairs] Status: NAD Concepts
+
          Section: 20.3.4 [pairs] Status: NAD Concepts
  Submitter: Dave Abrahams Opened: 2009-07-01  Last modified: 2009-07-16
          
 
          View other active issues in [pairs].
          
 
          View all other issues in [pairs].
          
@@ -28233,7 +38534,7 @@ Alternative Resolution: keep the ugly, complex specification and add the
 
 
          
 
          1168. Odd wording for bitset equality operators
          
-
          Section: 20.3.6.2 [bitset.members] Status: NAD Editorial
+
          Section: 20.3.7.2 [bitset.members] Status: NAD Editorial
  Submitter: Alisdair Meredith Opened: 2009-07-02  Last modified: 2009-07-27
          
 
          View all other issues in [bitset.members].
          
 
          View all issues with NAD Editorial status.
          
@@ -28242,7 +38543,7 @@ Alternative Resolution: keep the ugly, complex specification and add the
 The following wording seems a little unusual to me:
 
          
 
          
-p42/43 20.3.6.2 [bitset.members]
+p42/43 20.3.7.2 [bitset.members]
 
          
 
 
          
@@ -28289,7 +38590,7 @@ It's obviously editorial. There's no need for further discussion.
 
 
          Proposed resolution:
          
 
          
-Change 20.3.6.2 [bitset.members] p42-43:
+Change 20.3.7.2 [bitset.members] p42-43:
 
          
 
 
          
@@ -28312,4 +38613,2195 @@ Change 20.3.6.2 [bitset.members] p42-43:
 
 
 
+
          
+
          1172. select_on_container_(copy|move)_construction over-constrained
          
+
          Section: X [allocator.concepts.members] Status: NAD Editorial
+ Submitter: Alberto Ganesh Barbati Opened: 2009-07-08  Last modified: 2009-10-26
          
+
          View all issues with NAD Editorial status.
          
+
          Discussion:
          
+
          
+I believe the two functions
+select_on_container_(copy|move)_construction() are over-constrained. For
+example, the return value of the "copy" version is (see
+X [allocator.concepts.members]/21):
+
          
+
          
+Returns: x if the allocator should propagate from the existing
+container to the new container on copy construction, otherwise X().
+
          
+
          
+Consider the case where a user decides to provide an explicit concept
+map for Allocator to adapt some legacy allocator class, as he wishes to
+provide customizations that the LegacyAllocator concept map template
+does not provide.  Now, although it's true that the legacy class is
+required to have a default constructor, the user might have reasons to
+prefer a different constructor to implement
+select_on_container_copy_construction(). However, the current wording
+requires the use of the default constructor.
+
          
+
          
+Moreover, it's not said explicitly that x is supposed to be the
+allocator of the existing container. A clarification would do no harm.
+
          
+
+
          [
+2009-10 Santa Cruz:
+]
          
+
+
+
          
+NAD Editorial.  Addressed by
+N2982.
+
          
+
+
+
+
          Proposed resolution:
          
+
          
+Replace X [allocator.concepts.members]/21 with:
+
          
+
+
          X select_on_container_copy_construction(const X& x);
+
          
+
          
+-21- Returns: x if the allocator should propagate from the existing
+container to the new container on copy construction, otherwise X().
+an allocator object to be used by the new container on copy
+construction. [Note: x is the allocator of the existing container that
+is being copied. The most obvious choices for the return value are x, if
+the allocator should propagate from the existing container, and X().
+— end note]
+
          
+
          
+
+
          
+Replace X [allocator.concepts.members]/25 with:
+
          
+
+
          X select_on_container_move_construction(X&& x);
+
          
+
          
+-25- Returns: move(x) if the allocator should propagate from the existing
+container to the new container on move construction, otherwise X().
+an allocator object to be used by the new container on move
+construction. [Note: x is the allocator of the existing container that
+is being moved. The most obvious choices for the return value are move(x), if
+the allocator should propagate from the existing container, and X().
+— end note]
+
          
+
          
+
+
+
+
+
+
+
          
+
          1174. type property predicates
          
+
          Section: 20.6.4.3 [meta.unary.prop] Status: NAD Editorial
+ Submitter: Jason Merrill Opened: 2009-07-16  Last modified: 2009-10-26
          
+
          View other active issues in [meta.unary.prop].
          
+
          View all other issues in [meta.unary.prop].
          
+
          View all issues with NAD Editorial status.
          
+
          Discussion:
          
+
          
+I've been implementing compiler support for is_standard_layout, and
+noticed a few nits about 20.6.4.3 [meta.unary.prop]:
+
          
+
+
            
+
          1. 
+There's no trait for "trivially copyable type", which is now the
+property that lets you do bitwise copying of a type, and therefore seems
+useful to be able to query.  has_trivial_assign &&
+has_trivial_copy_constructor && has_trivial_destructor
+is similar, but
+not identical, specifically with respect to const types.
+
            2. 
+
          2. 
+has_trivial_copy_constructor and has_trivial_assign lack the "or an
+array of such a class type" language that most other traits in that
+section, including has_nothrow_copy_constructor and has_nothrow_assign,
+have; this seems like an oversight.
+
            3. 
+
          
+
+
          [
+See the thread starting with c++std-lib-24420 for further discussion.
+]
          
+
+
+
          [
+Addressed in N2947.
+]
          
+
+
+
          [
+2009-10 Santa Cruz:
+]
          
+
+
+
          
+NAD Editorial.  Solved by
+N2984.
+
          
+
+
+
+
          Proposed resolution:
          
+
          
+
          
+
+
+
+
+
+
          
+
          1179. Probably editorial in [structure.specifications]
          
+
          Section: 17.5.1.4 [structure.specifications] Status: NAD Editorial
+ Submitter: Robert Klarer Opened: 2009-07-21  Last modified: 2009-10-20
          
+
          View all other issues in [structure.specifications].
          
+
          View all issues with NAD Editorial status.
          
+
          Discussion:
          
+
          
+While reviewing 971 I noted that 17.5.1.4 [structure.specifications]/7 says:
+
          
+
+
          
+-7- Error conditions specify conditions where a function may fail. The
+conditions are listed, together with a suitable explanation, as the enum
+class errc constants (19.5) that could be used as an argument to
+function make_error_condition (19.5.3.6).
+
          
+
+
          
+This paragraph should mention make_error_code or the text "that
+could be used as an argument to function make_error_condition
+(19.5.3.6)" should be deleted.  I believe this is editorial.
+
          
+
+
          [
+2009-07-21 Chris adds:
+]
          
+
+
+
          
+
          
+I'm not convinced there's a problem there, because as far as the "Error
+conditions" clauses are concerned, make_error_condition() is used by a
+user to test for the condition, whereas make_error_code is not. For
+example:
+
          
+
+
          void foobar(error_code& ec = throws());
+
          
+
+
          
+ Error conditions:
+
          
+
          
+permission_denied - Insufficient privilege to perform operation.
+
          
+
+
          
+When a user writes:
+
          
+
+
          error_code ec;
+foobar(ec);
+if (ec == errc::permission_denied)
+   ...
+
          
+
+
          
+the implicit conversion errc->error_condition makes the if-test
+equivalent to:
+
          
+
+
          if (ec == make_error_condition(errc::permission_denied))
+
          
+
+
          
+On the other hand, if the user had written:
+
          
+
+
          if (ec == make_error_code(errc::permission_denied))
+
          
+
+
          
+the test is now checking for a specific error code. The test may
+evaluate to false even though foobar() failed due to the documented
+error condition "Insufficient privilege".
+
          
+
          
+
+
          [
+2009 Santa Cruz:
+]
          
+
+
+
          
+
          
+NAD Editorial.
+
          
+
          
+What the WP says right now is literally true: these codes can be used as
+an argument to make_error_condition. (It is also true that they can be
+used as an argument to make_error_code, which the WP doesn't say.) Maybe
+it would be clearer to just delete "that could be used as an argument to
+function make_error_condition", since that fact is already implied by
+other things that we say. We believe that this is editorial.
+
          
+
          
+
+
+
+
          Proposed resolution:
          
+
          
+
          
+
+
+
+
+
+
          
+
          1184. Feature request: dynamic bitset
          
+
          Section: 23.3.6 [vector] Status: NAD Future
+ Submitter: Alisdair Meredith Opened: 2009-07-29  Last modified: 2009-10-26
          
+
          View all other issues in [vector].
          
+
          View all issues with NAD Future status.
          
+
          Discussion:
          
+
          
+Opened at Alisdair's request, steming from 96.
+Alisdair recommends NAD Future.
+
          
+
+
          [
+2009-10 Santa Cruz:
+]
          
+
+
+
          
+NAD Future.  We want a heap allocated bitset, but we don't have one today and
+don't have time to add one.
+
          
+
+
+
+
          Proposed resolution:
          
+
+
+
+
+
+
          
+
          1195. "Diagnostic required" wording is insufficient to  prevent UB
          
+
          Section: 17 [library] Status: NAD Editorial
+ Submitter: Daniel Krügler Opened: 2009-08-18  Last modified: 2009-10-20
          
+
          View other active issues in [library].
          
+
          View all other issues in [library].
          
+
          View all issues with NAD Editorial status.
          
+
          Discussion:
          
+
          
+Several parts of the library use the notion of "Diagnostic required"
+to indicate that
+in the corresponding situation an error diagnostic should occur, e.g.
+20.8.14.1.1 [unique.ptr.dltr.dflt]/2
+
          
+
          void operator()(T *ptr) const;
+
          
+
+
          
+Effects: calls delete on ptr. A diagnostic is required if T is an
+incomplete type.
+
          
+
          
+
+
          
+The problem with this approach is that such a requirement is
+insufficient to prevent
+undefined behavior, if this situation occurs. According to 1.3.3 [defns.diagnostic]
+a diagnostic message is defined as
+
          
+
+
          
+a message belonging to an implementation-defined subset of the
+implementation's output messages.
+
          
+
+
          
+which doesn't indicate any relation to an ill-formed program. In fact,
+"compiler warnings"
+are a typical expression of such diagnostics. This means that above
+wording can be interpreted
+by compiler writers that they satisfy the requirements of the standard
+if they just produce
+such a "warning", if the compiler happens to compile code like this:
+
          
+
+
          #include <memory>
+
+struct Ukn; // defined somewhere else
+Ukn* create_ukn(); // defined somewhere else
+
+int main() {
+ std::default_delete<Ukn>()(create_ukn());
+}
+
          
+
+
          
+In this and other examples discussed here it was the authors intent to
+guarantee that the
+program is ill-formed with a required diagnostic, therefore such
+wording should be used instead.
+According to the general rules outlined in 1.4 [intro.compliance] it
+should be sufficient
+to require that these situations produce an ill-formed program and the
+"diagnostic
+required" part should be implied. The proposed resolution also
+suggests to remove
+several redundant wording of "Diagnostics required" to ensure that
+the absence of
+such saying does not cause a misleading interpretation.
+
          
+
+
          [
+2009 Santa Cruz:
+]
          
+
+
+
          
+
          
+Move to NAD.
+
          
+
          It's not clear that there's any important difference between
+"ill-formed" and "diagnostic required". From 1.4 [intro.compliance],
+1.3.5 [defns.ill.formed], and 1.3.15 [defns.well.formed] it appears
+that an ill-formed program is one
+that is not correctly constructed according to the syntax rules and
+diagnosable semantic rules, which means that... "a conforming
+implementation shall issue at least one diagnostic message." The
+author's intent seems to be that we should be requiring a fatal error
+instead of a mere warning, but the standard just doesn't have language
+to express that distinction. The strongest thing we can ever require is
+a "diagnostic".
+
          
+
          
+The proposed rewording may be a clearer way of expressing the same thing
+that the WP already says, but such a rewording is editorial.
+
          
+
          
+
+
          [
+2009 Santa Cruz:
+]
          
+
+
+
          
+Considered again.  Group disagrees that the change is technical, but likes
+it editorially.  Moved to NAD Editorial.
+
          
+
+
+
+
          Proposed resolution:
          
+
            
+
          1. 
+
            
+Change 20.4 [ratio]/2 as indicated:
+
            
+
+
+
+
            
+Throughout this subclause, the template argument types R1 and R2 shall
+be specializations of the ratio
+template, else the program is ill-formed. Diagnostic required.
+
            
+
            2. 
+
+
          2. 
+
            
+Change 20.4.1 [ratio.ratio]/1 as indicated:
+
            
+
+
            
+The template argument D shall not be zero, and the absolute values of
+the template arguments N and D shall
+be representable by type intmax_t, else the program is ill-formed. Diagnostic required. [..]
+
            
+
+
+
            3. 
+
+
          3. 
+
            
+Change 20.4.2 [ratio.arithmetic]/1 as indicated:
+
            
+
+
            
+Implementations may use other algorithms to compute these values.
+If overflow would occurs, a diagnostic shall
+be issuedthe program shall be ill-formed.
+
            
+
+
            4. 
+
+
          4. 
+
            
+Change 20.4.3 [ratio.comparison]/2 as indicated:
+
            
+
+
            
+[...] Implementations may use other algorithms to compute this relationship
+to avoid overflow. If
+overflow occurs, a diagnostic is required would occur,
+the program shall be
+ill-formed.
+
            
+
+
+
            5. 
+
+
          5. 
+
            
+Change 20.8.14.1.1 [unique.ptr.dltr.dflt]/2 as indicated:
+
            
+
+
            
+
            
+Effects: calls delete on ptr. A diagnostic is required if T is an
+incomplete type.
+
            
+
+
            
+Remarks: The program shall be ill-formed, if T is an incomplete type.
+
            
+
            
+
+
+
            6. 
+
+
          6. 
+
            
+Change 20.8.14.1.2 [unique.ptr.dltr.dflt1]/1 as indicated:
+
            
+
+
            
+
            
+operator() calls delete[] on ptr. A diagnostic is required if T
+is an incomplete type.
+
            
+
+
            
+Remarks: The program shall be ill-formed, if T is an incomplete type.
+
            
+
            
+
            7. 
+
+
          7. 
+
            
+Accept 932.
+
            
+
+
            [This is a bullet here to confirm that this list is
+an exhaustive review of this issue.]
            
+
+
            8. 
+
+
          8. 
+
            
+Accept 950.
+
            
+
+
            [This is a bullet here to confirm that this list is
+an exhaustive review of this issue.]
            
+
+
            9. 
+
+
          9. 
+
            
+Change 20.8.14.3 [unique.ptr.runtime]/1 as indicated:
+
            
+
+
            
+[..]
+-- Conversions among different types of unique_ptr<T[], D> or to or
+from the non-array forms of
+unique_ptr are disallowed (diagnostic required)
+produce an ill-formed program.
+[..]
+
            
+
+
+
            10. 
+
+
          10. 
+
            
+Change 20.9.3 [time.duration]/2 as indicated:
+
            
+
+
            
+Requires: Rep shall be an arithmetic type or a class emulating an
+arithmetic type. If a program
+instantiates duration with a duration type for the template argument
+Rep a diagnostic is required.
+Remarks: The program shall be ill-formed, if duration is
+instantiated with a duration type for the template argument Rep.
+
+
            
+
+
+
            11. 
+
+
          11. 
+
            
+Change 20.9.3 [time.duration]/3+4 as indicated:
+
            
+
+
            
+
            
+3 RequiresRemarks: Period shall be a
+specialization of ratio, diagnostic
+requiredelse the program shall be ill-formed.
+
            
+
+
            
+4 RequiresRemarks: Period::num shall be
+positive,  diagnostic
+requiredelse the program shall be ill-formed.
+
            
+
            
+
+
+
            12. 
+
+
          12. 
+
            
+Accept 1177 bullet 1.
+
            
+
+
            [This is a bullet here to confirm that this list is
+an exhaustive review of this issue.]
            
+
+
+
            13. 
+
+
          13. 
+
            
+Accept 1177 bullet 2.
+
            
+
+
            [This is a bullet here to confirm that this list is
+an exhaustive review of this issue.]
            
+
+
+
            14. 
+
+
          14. 
+
            
+Accept 1177 bullet 3.
+
            
+
+
            [This is a bullet here to confirm that this list is
+an exhaustive review of this issue.]
            
+
+
+
            15. 
+
+
          15. 
+
            
+Change 20.9.4 [time.point]/2 as indicated:
+
            
+
+
            
+Duration shall be an instance of duration, else the
+program shall be ill-formed. Diagnostic required.
+
            
+
            16. 
+
+
          16. 
+
            
+Change 20.9.4.1 [time.point.cons]/3 as indicated:
+
            
+
+
            
+
            
+Requires: Duration2 shall be implicitly convertible to duration.
+Diagnostic required.
+
            
+
+
            
+Remarks: Duration2 shall be implicitly convertible to duration,
+else this constructor shall
+not participate in overload resolution.
+
            
+
            
+
+
            [This suggestion seems more in sync to the several suggested changes
+of 1177, 950, etc.]
            
+
+
            17. 
+
+
          17. 
+
            
+Accept 1177 bullet 4.
+
            
+
+
            [This is a bullet here to confirm that this list is
+an exhaustive review of this issue.]
            
+
+
+
            18. 
+
+
          
+
+
+
+
+
+
+
          
+
          1196. move semantics undefined for priority_queue
          
+
          Section: 23.3.5.2.1 [priqueue.cons] Status: NAD Editorial
+ Submitter: Alisdair Meredith Opened: 2009-08-19  Last modified: 2009-10-20
          
+
          View all issues with NAD Editorial status.
          
+
          Discussion:
          
+
          
+The class template priority_queue declares signatures for a move
+constructor and move assignment operator in its class definition.
+However, it does not provide a definition (unlike std::queue, and
+proposed resolution for std::stack.) Nor does it provide a text clause
+specifying their behaviour.
+
          
+
+
          [
+2009-08-23 Daniel adds:
+]
          
+
+
+
          
+1194 provides wording that solves this issue.
+
          
+
+
          [
+2009-10 Santa Cruz:
+]
          
+
+
+
          
+Mark NAD Editorial, solved by issue 1194.
+
          
+
+
+
+
          Proposed resolution:
          
+
+
+
+
+
+
          
+
          1203. More useful rvalue stream insertion
          
+
          Section: 27.7.2.9 [ostream.rvalue], 27.7.1.6 [istream.rvalue] Status: NAD Future
+ Submitter: Howard Hinnant Opened: 2009-09-06  Last modified: 2009-10-20
          
+
          View all issues with NAD Future status.
          
+
          Discussion:
          
+
          
+27.7.2.9 [ostream.rvalue] was created to preserve the ability to insert
+into (and extract from 27.7.1.6 [istream.rvalue]) rvalue streams:
+
          
+
+
          template <class charT, class traits, class T>
+  basic_ostream<charT, traits>&
+  operator<<(basic_ostream<charT, traits>&& os, const T& x);
+
          
+
          
+
          
+1 Effects: os << x
+
          
+
          
+2 Returns: os
+
          
+
          
+
          
+
+
          
+This is good as it allows code that wants to (for example) open, write to, and
+close an ofstream all in one statement:
+
          
+
+
          std::ofstream("log file") << "Some message\n";
+
          
+
+
          
+However, I think we can easily make this "rvalue stream helper" even easier to
+use.  Consider trying to quickly create a formatted string.  With the current
+spec you have to write:
+
          
+
+
          std::string s = static_cast<std::ostringstream&>(std::ostringstream() << "i = " << i).str();
+
          
+
+
          
+This will store "i = 10" (for example) in the string s.  Note
+the need to cast the stream back to ostringstream& prior to using
+the member .str().  This is necessary because the inserter has cast
+the ostringstream down to a more generic ostream during the
+insertion process.
+
          
+
+
          
+I believe we can re-specify the rvalue-inserter so that this cast is unnecessary.
+Thus our customer now has to only type:
+
          
+
+
          std::string s = (std::ostringstream() << "i = " << i).str();
+
          
+
+
          
+This is accomplished by having the rvalue stream inserter return an rvalue of
+the same type, instead of casting it down to the base class.  This is done by
+making the stream generic, and constraining it to be an rvalue of a type derived
+from ios_base.
+
          
+
+
          
+The same argument and solution also applies to the inserter.  This code has been
+implemented and tested.
+
          
+
+
          [
+2009 Santa Cruz:
+]
          
+
+
+
          
+NAD Future.  No concensus for change.
+
          
+
+
+
+
          Proposed resolution:
          
+
          
+Change 27.7.1.6 [istream.rvalue]:
+
          
+
+
          template <class charT, class traits Istream, class T>
+  basic_istream<charT, traits>& Istream&&
+  operator>>(basic_istream<charT, traits> Istream&& is, T& x);
+
          
+
          
+
          
+1 Effects: is >> x
+
          
+
          
+2 Returns: std::move(is)
+
          
+
          
+3 Remarks: This signature shall participate in overload resolution if
+and only if Istream is not an lvalue reference type and is derived from
+ios_base.
+
          
+
          
+
          
+
+
          
+Change 27.7.2.9 [ostream.rvalue]:
+
          
+
+
          template <class charT, class traits Ostream, class T>
+  basic_ostream<charT, traits>& Ostream&&
+  operator<<(basic_ostream<charT, traits> Ostream&& os, const T& x);
+
          
+
          
+
          
+1 Effects: os << x
+
          
+
          
+2 Returns: std::move(os)
+
          
+
          
+3 Remarks: This signature shall participate in overload resolution if
+and only if Ostream is not an lvalue reference type and is derived from
+ios_base.
+
          
+
          
+
          
+
+
+
+
+
+
+
          
+
          1217. Quaternion support
          
+
          Section: 26.4 [complex.numbers] Status: NAD Future
+ Submitter: Ted Shaneyfelt Opened: 2009-09-26  Last modified: 2009-10-26
          
+
          View all other issues in [complex.numbers].
          
+
          View all issues with NAD Future status.
          
+
          Discussion:
          
+
          
+Concerning mathematically proper operation of the type:
+
          
+
+
          complex<complex<T> >
+
          
+
+
          
+Generally accepted mathematical semantics of such a construct correspond
+to quaternions through Cayly-Dickson construct
+
          
+
+
          (w+xi) + (y+zi) j
+
          
+
+
          
+The proper implementation seems straightforward by adding a few
+declarations like those below. I have included operator definition for
+combining real scalars and complex types, as well, which seems
+appropriate, as algebra of complex numbers allows mixing complex and
+real numbers with operators. It also allows for constructs such as
+complex<double> i=(0,1),  x = 12.34 + 5*i;
+
          
+
+
          
+Quaternions are often used in areas such as computer graphics, where,
+for example, they avoid the problem of Gimbal lock when rotating objects
+in 3D space, and can be more efficient than matrix multiplications,
+although I am applying them to a different field.
+
          
+
+
          /////////////////////////ALLOW OPERATORS TO COMBINE REAL SCALARS AND COMPLEX VALUES /////////////////////////
+template<typename T,typename S> complex<T> operator+(const complex<T> x,const S a) {
+    complex<T> result(x.real()+a, x.imag());
+    return result;
+}
+template<typename T,typename S> complex<T> operator+(const S a,const complex<T> x) {
+    complex<T> result(a+x.real(), x.imag());
+    return result;
+}
+template<typename T,typename S> complex<T> operator-(const complex<T> x,const S a) {
+    complex<T> result(x.real()-a, x.imag());
+    return result;
+}
+template<typename T,typename S> complex<T> operator-(const S a,const complex<T> x) {
+    complex<T> result(a-x.real(), x.imag());
+    return result;
+}
+template<typename T,typename S> complex<T> operator*(const complex<T> x,const S a) {
+    complex<T> result(x.real()*a, x.imag()*a);
+    return result;
+}
+template<typename T,typename S> complex<T> operator*(const S a,const complex<T> x) {
+    complex<T> result(a*x.real(), a*x.imag());
+    return result;
+}
+
+/////////////////////////PROPERLY IMPLEMENT QUATERNION SEMANTICS/////////////////////////
+template<typename T> double normSq(const complex<complex<T> >q) {
+    return q.real().real()*q.real().real()
+         + q.real().imag()*q.real().imag()
+         + q.imag().real()*q.imag().real()
+         + q.imag().imag()*q.imag().imag();
+}
+template<typename T> double norm(const complex<complex<T> >q) {
+    return sqrt(normSq(q));
+}
+/////// Cayley-Dickson Construction
+template<typename T> complex<complex<T> > conj(const complex<complex<T> > x) {
+    complex<complex<T> > result(conj(x.real()),-x.imag());
+    return result;
+}
+template<typename T> complex<complex<T> > operator*(const complex<complex<T> > ab,const complex<complex<T> > cd) {
+    complex<T> re(ab.real()*cd.real()-conj(cd.imag())*ab.imag());
+    complex<T> im(cd.imag()*ab.real()+ab.imag()*conj(cd.real()));
+    complex<complex<double> > q(re,im);
+    return q;
+}
+//// Quaternion division
+template<typename S,typename T> complex<complex<T> > operator/(const complex<complex<T> > q,const S a) {
+    return q * (1/a);
+}
+template<typename S,typename T> complex<complex<T> > operator/(const S a,const complex<complex<T> > q) {
+    return a*conj(q)/normSq(q);
+}
+template<typename T> complex<complex<T> > operator/(const complex<complex<T> > n, const complex<complex<T> > d) {
+    return n * (conj(d)/normSq(d));
+}
+
          
+
+
          [
+2009-10 Santa Cruz:
+]
          
+
+
+
          
+NAD Future.  There is no consensus or time to move this into C++0X.
+
          
+
+
+
+
          Proposed resolution:
          
+
+
+
+
+
+
          
+
          1229. error_code operator= typo
          
+
          Section: 19.5.2.3 [syserr.errcode.modifiers] Status: NAD
+ Submitter: Stephan T. Lavavej Opened: 2009-10-08  Last modified: 2009-10-26
          
+
          View all issues with NAD status.
          
+
          Discussion:
          
+
          
+N2960
+19.5.2.1 [syserr.errcode.overview] and 19.5.2.3 [syserr.errcode.modifiers] say:
+
          
+
+
           
+template <class ErrorCodeEnum>
+  typename enable_if<is_error_code_enum<ErrorCodeEnum>::value>::type&
+    operator=(ErrorCodeEnum e);
+
          
+
+
          
+They should say:
+
          
+
+
           
+template <class ErrorCodeEnum>
+  typename enable_if<is_error_code_enum<ErrorCodeEnum>::value, error_code>::type&
+    operator=(ErrorCodeEnum e);
+
          
+
+
          
+Or (I prefer this form):
+
          
+ 
+
           
+template <class ErrorCodeEnum>
+  typename enable_if<is_error_code_enum<ErrorCodeEnum>::value, error_code&>::type
+    operator=(ErrorCodeEnum e);
+
          
+
+
          
+This is because enable_if is declared as (20.6.7 [meta.trans.other]):
+
          
+ 
+
           
+template <bool B, class T = void> struct enable_if;
+
          
+
+
          
+So, the current wording makes operator= return
+void&, which is not good.
+
          
+
+
           
+19.5.2.3 [syserr.errcode.modifiers]/4 says
+
          
+
+
          
+Returns: *this.
+
          
+
          
+which is correct.
+
          
+
+
          
+Additionally,
+
          
+
+
          
+19.5.3.1 [syserr.errcondition.overview]/1 says:
+
          
+ 
+
           
+template<typename ErrorConditionEnum>
+  typename enable_if<is_error_condition_enum<ErrorConditionEnum>, error_code>::type &
+    operator=( ErrorConditionEnum e );
+
          
+
+
          
+Which contains several problems (typename versus class
+inconsistency, lack of ::value, error_code instead of
+error_condition), while 19.5.3.3 [syserr.errcondition.modifiers] says:
+
          
+ 
+
           
+template <class ErrorConditionEnum>
+  typename enable_if<is_error_condition_enum<ErrorConditionEnum>::value>::type&
+    operator=(ErrorConditionEnum e);
+
          
+
+
          
+Which returns void&.  They should both say:
+
          
+ 
+
           
+template <class ErrorConditionEnum>
+  typename enable_if<is_error_condition_enum<ErrorConditionEnum>::value, error_condition>::type&
+    operator=(ErrorConditionEnum e);
+
          
+
+
          
+Or (again, I prefer this form):
+
          
+
+
           
+template <class ErrorConditionEnum>
+  typename enable_if<is_error_condition_enum<ErrorConditionEnum>::value, error_condition&>::type
+    operator=(ErrorConditionEnum e);
+
          
+
+
          
+Additionally, 19.5.3.3 [syserr.errcondition.modifiers] lacks a
+"Returns: *this." paragraph, which is presumably
+necessary.
+
          
+
+
          [
+2009-10-18 Beman adds:
+]
          
+
+
+
          
+The proposed resolution for issue 1237 makes this issue
+moot, so it should become NAD.
+
          
+
+
          [
+2009-10 Santa Cruz:
+]
          
+
+
+
          
+NAD, solved by 1237.
+
          
+
+
+
+
          Proposed resolution:
          
+
+
          
+Change 19.5.2.1 [syserr.errcode.overview] and 19.5.2.3 [syserr.errcode.modifiers]:
+
          
+
+
          template <class ErrorCodeEnum>
+  typename enable_if<is_error_code_enum<ErrorCodeEnum>::value, error_code&>::type&
+    operator=(ErrorCodeEnum e);
+
          
+
+
          
+Change 19.5.3.1 [syserr.errcondition.overview]:
+
          
+
+
          template<typename class ErrorConditionEnum>
+  typename enable_if<is_error_condition_enum<ErrorConditionEnum>::value, error_conditionde&>::type &
+    operator=( ErrorConditionEnum e );
+
          
+
+
          
+Change 19.5.3.3 [syserr.errcondition.modifiers]:
+
          
+
+
          template <class ErrorConditionEnum>
+  typename enable_if<is_error_condition_enum<ErrorConditionEnum>::value, error_condition&>::type&
+    operator=(ErrorConditionEnum e);
+
          
+
          
+
          
+Postcondition: *this == make_error_condition(e).
+
          
+
          
+Returns: *this.
+
          
+
          
+Throws: Nothing.
+
          
+
          
+
          
+
+
+
+
+
+
+
          
+
          1230. mem_fn and variadic templates
          
+
          Section: 20.7.14 [func.memfn] Status: Dup
+ Submitter: Alisdair Meredith Opened: 2009-10-09  Last modified: 2009-10-23
          
+
          View all other issues in [func.memfn].
          
+
          View all issues with Dup status.
          
+
          Duplicate of: 920
          
+
          Discussion:
          
+
+
+
+
          
+Since we have removed the entry in B [implimits] for the
+library-specific limit for number of arguments passed to
+function/tuple/etc. I believe we need to update the
+spec for mem_fn to reflect this.
+
          
+
+
          
+The "Remarks: Implementations may implement mem_fn as a set of
+overloaded function templates." no longer holds, as we cannot create an
+arbitrary number of such overloads.  I believe we should strike the
+remark and add a second signature:
+
          
+
+
          template<class R, class T, typename ... ArgTypes>
+  unspecified mem_fn(R (T::*pm)(ArgTypes...));
+
          
+
+
          
+I believe we need two signatures as pointer-to-data-member and
+pointer-to-member-function-taking-no-args appear to use subtly different
+syntax.
+
          
+
+
          [
+920 as a similar proposed resolution.
+]
          
+
+
+
+
          Proposed resolution:
          
+Add to 20.7 [function.objects] and 20.7.14 [func.memfn]:
+
+
+
          template<class R, class T> unspecified mem_fn(R T::* pm)
+
+template<class R, class T, class ...Args> unspecified mem_fn(R (T::* pm)(Args...));
+template<class R, class T, class ...Args> unspecified mem_fn(R (T::* pm)(Args...) const);
+template<class R, class T, class ...Args> unspecified mem_fn(R (T::* pm)(Args...) volatile);
+template<class R, class T, class ...Args> unspecified mem_fn(R (T::* pm)(Args...) const volatile);
+
+template<class R, class T, class ...Args> unspecified mem_fn(R (T::* pm)(Args...)&);
+template<class R, class T, class ...Args> unspecified mem_fn(R (T::* pm)(Args...) const&);
+template<class R, class T, class ...Args> unspecified mem_fn(R (T::* pm)(Args...) volatile&);
+template<class R, class T, class ...Args> unspecified mem_fn(R (T::* pm)(Args...) const volatile&);
+
+template<class R, class T, class ...Args> unspecified mem_fn(R (T::* pm)(Args...)&&);
+template<class R, class T, class ...Args> unspecified mem_fn(R (T::* pm)(Args...) const&&);
+template<class R, class T, class ...Args> unspecified mem_fn(R (T::* pm)(Args...) volatile&&);
+template<class R, class T, class ...Args> unspecified mem_fn(R (T::* pm)(Args...) const volatile&&);
+
          
+
+
          
+Strike 20.7.14 [func.memfn], p5:
+
          
+
+
          
+Remarks: Implementations may implement mem_fn as a set
+of overloaded function templates.
+
          
+
+
+
+
+
          
+
          1232. Still swap's with rvalue-references
          
+
          Section: 17 [library] Status: NAD Editorial
+ Submitter: Daniel Krügler Opened: 2009-10-11  Last modified: 2009-10-29
          
+
          View other active issues in [library].
          
+
          View all other issues in [library].
          
+
          View all issues with NAD Editorial status.
          
+
          Discussion:
          
+
          
+The current library contains still rvalue reference-swaps that seem to be
+overlooked in the process of switching back to lvalue-ref swaps.
+
          
+
+
          [
+2009-10 Santa Cruz:
+]
          
+
+
+
          
+Editor accepts as NAD Editorial.
+
          
+
+
+
+
          Proposed resolution:
          
+
            
+
          1. 
+
            
+Change 20.3.4 [pairs]/1 as indicated:
+
            
+
+
            template <class T1, class T2>
+struct pair {
+  ...
+  void swap(pair&& p);
+};
+
            
+
            2. 
+
+
          2. 
+
            
+Change 20.3.4 [pairs] before p. 17 as indicated:
+
            
+
+
            void swap(pair&& p);
+
            
+
+
            3. 
+
+
          3. 
+
+
            
+Change 20.3.4 [pairs] before p. 21 as indicated:
+
            
+
+
            template<class T1, class T2> void swap(pair<T1, T2>& x, pair<T1, T2>& y);
+template<class T1, class T2> void swap(pair<T1, T2>&& x, pair<T1, T2>& y);
+template<class T1, class T2> void swap(pair<T1, T2>& x, pair<T1, T2>&& y);
+
            
+
+
            4. 
+
+
          4. 
+
            
+Change 20.5.1 [tuple.general]/2, header <tuple> synopsis, as indicated:
+
            
+
+
            // 20.5.2.9, specialized algorithms:
+template <class... Types>
+void swap(tuple<Types...>& x, tuple<Types...>& y);
+template <class... Types>
+void swap(tuple<Types...>&& x, tuple<Types...>& y);
+template <class... Types>
+void swap(tuple<Types...>& x, tuple<Types...>&& y);
+
            
+
+
            5. 
+
+
          5. 
+
            
+Change 20.5.2 [tuple.tuple] as indicated:
+
            
+
+
            // 20.5.2.3, tuple swap
+void swap(tuple&&)
+
            
+
+
            6. 
+
+
          6. 
+
            
+Change 20.5.2.3 [tuple.swap] before 1 as indicated:
+
            
+
+
            void swap(tuple&& rhs);
+
            
+
+
            7. 
+
+
          7. 
+
            
+Change 20.7 [function.objects]/2, header <functional> synopsis, as indicated:
+
            
+
+
            template<class R, class... ArgTypes>
+void swap(function<R(ArgTypes...)>&, function<R(ArgTypes...)>&);
+template<class R, class... ArgTypes>
+void swap(function<R(ArgTypes...)>&&, function<R(ArgTypes...)>&);
+template<class R, class... ArgTypes>
+void swap(function<R(ArgTypes...)>&, function<R(ArgTypes...)&&);
+
            
+
+
            8. 
+
+
          8. 
+
            
+Change 20.7.15.2 [func.wrap.func], as indicated:
+
            
+
+
            // 20.7.15.2.2, function modifiers:
+void swap(function&&);
+template<class F, class A> void assign(F, const A&);
+
+[..]
+
+// 20.7.15.2.7, specialized algorithms:
+template <class R, class... ArgTypes>
+void swap(function<R(ArgTypes...)>&, function<R(ArgTypes...)>&);
+template <class R, class... ArgTypes>
+void swap(function<R(ArgTypes...)>&&, function<R(ArgTypes...)>&);
+template <class R, class... ArgTypes>
+void swap(function<R(ArgTypes...)>&, function<R(ArgTypes...)>&&);
+
            
+
+
            9. 
+
+
          9. 
+
            
+Change 20.7.15.2.7 [func.wrap.func.alg] before 1 as indicated:
+
            
+
+
            template<class R, class... ArgTypes>
+void swap(function<R(ArgTypes...)>& f1, function<R(ArgTypes...)>& f2);
+template<class R, class... ArgTypes>
+void swap(function<R(ArgTypes...)>&& f1, function<R(ArgTypes...)>& f2);
+template<class R, class... ArgTypes>
+void swap(function<R(ArgTypes...)>& f1, function<R(ArgTypes...)>&& f2);
+
            
+
+
            10. 
+
+
          10. 
+
            
+Change 20.8.15.2 [util.smartptr.shared]/1 as indicated:
+
            
+
+
            // 20.8.12.2.4, modifiers:
+void swap(shared_ptr&& r);
+
+[..]
+
+// 20.8.12.2.9, shared_ptr specialized algorithms:
+template<class T> void swap(shared_ptr<T>& a, shared_ptr<T>& b);
+template<class T> void swap(shared_ptr<T>&& a, shared_ptr<T>& b);
+template<class T> void swap(shared_ptr<T>& a, shared_ptr<T>&& b);
+
            
+
+
            11. 
+
+
          11. 
+
            
+Change 21.3 [string.classes]/1, header <string> synopsis, as indicated:
+
            
+
+
            // 21.4.8.8: swap
+template<class charT, class traits, class Allocator>
+void swap(basic_string<charT,traits,Allocator>& lhs, basic_string<charT,traits,Allocator>& rhs);
+template<class charT, class traits, class Allocator>
+void swap(basic_string<charT,traits,Allocator>&& lhs, basic_string<charT,traits,Allocator>& rhs);
+template<class charT, class traits, class Allocator>
+void swap(basic_string<charT,traits,Allocator>& lhs, basic_string<charT,traits,Allocator>&& rhs);
+
            
+
+
            12. 
+
+
          12. 
+
            
+Change 23.3 [sequences]/1, header <deque> synopsis, as indicated:
+
            
+
+
            template <class T, class Allocator>
+void swap(deque<T,Allocator>& x, deque<T,Allocator>& y);
+template <class T, class Allocator>
+void swap(deque<T,Allocator>&& x, deque<T,Allocator>& y);
+template <class T, class Allocator>
+void swap(deque<T,Allocator>& x, deque<T,Allocator>&& y);
+
            
+
+
            13. 
+
+
          13. 
+
            
+Change 23.3 [sequences]/1, header <list> synopsis, as indicated:
+
            
+
+
            template <class T, class Allocator>
+void swap(list<T,Allocator>& x, list<T,Allocator>& y);
+template <class T, class Allocator>
+void swap(list<T,Allocator>&& x, list<T,Allocator>& y);
+template <class T, class Allocator>
+void swap(list<T,Allocator>& x, list<T,Allocator>&& y);
+
            
+
+
            14. 
+
+
          14. 
+
            
+Change 23.3 [sequences]/1, header <queue> synopsis, as indicated:
+
            
+
+
            template <class T, class Allocator>
+void swap(queue<T, Container>& x, queue<T, Container>& y);
+template <class T, class Container>
+void swap(queue<T, Container>&& x, queue<T, Container>& y);
+template <class T, class Container>
+void swap(queue<T, Container>& x, queue<T, Container>&& y);
+
+template <class T, class Container = vector<T>, class Compare = less<typename Container::value_type> >
+class priority_queue;
+template <class T, class Container, class Compare>
+void swap(priority_queue<T, Container, Compare>& x, priority_queue<T, Container, Compare>& y);
+template <class T, class Container, class Compare>
+void swap(priority_queue<T, Container, Compare>&& x, priority_queue<T, Container, Compare>& y);
+template <class T, class Container, class Compare>
+void swap(priority_queue<T, Container, Compare>& x, priority_queue<T, Container, Compare>&& y);
+
            
+
+
            15. 
+
+
          15. 
+
            
+Change 23.3 [sequences]/1, header <stack> synopsis, as indicated:
+
            
+
+
            template <class T, class Container>
+void swap(stack<T, Container>& x, stack<T, Container>& y);
+template <class T, class Container>
+void swap(stack<T, Container>&& x, stack<T, Container>& y);
+template <class T, class Container>
+void swap(stack<T, Container>& x, stack<T, Container>&& y);
+
            
+
+
            16. 
+
+
          16. 
+
            
+Change 23.3 [sequences]/1, header <vector> synopsis, as indicated:
+
            
+
+
            template <class T, class Allocator>
+void swap(vector<T,Allocator>& x, vector<T,Allocator>& y);
+template <class T, class Allocator>
+void swap(vector<T,Allocator>&& x, vector<T,Allocator>& y);
+template <class T, class Allocator>
+void swap(vector<T,Allocator>& x, vector<T,Allocator>&& y);
+
            
+
+
            17. 
+
+
          17. 
+
            
+Change 23.3.2 [deque]/2 as indicated:
+
            
+
+
            iterator erase(const_iterator position);
+iterator erase(const_iterator first, const_iterator last);
+void swap(deque<T,Allocator>&&);
+void clear();
+
+[..]
+
+// specialized algorithms:
+template <class T, class Allocator>
+void swap(deque<T,Allocator>& x, deque<T,Allocator>& y);
+template <class T, class Allocator>
+void swap(deque<T,Allocator>&& x, deque<T,Allocator>& y);
+template <class T, class Allocator>
+void swap(deque<T,Allocator>& x, deque<T,Allocator>&& y);
+
            
+
+
            18. 
+
+
          18. 
+
            
+Change 23.3.2.4 [deque.special] as indicated:
+
            
+
+
            template <class T, class Allocator>
+void swap(deque<T,Allocator>& x, deque<T,Allocator>& y);
+template <class T, class Allocator>
+void swap(deque<T,Allocator>&& x, deque<T,Allocator>& y);
+template <class T, class Allocator>
+void swap(deque<T,Allocator>& x, deque<T,Allocator>&& y);
+
            
+
+
            19. 
+
+
          19. 
+
            
+Change 23.3.3 [forwardlist]/2 as indicated:
+
            
+
+
            iterator erase_after(const_iterator position);
+iterator erase_after(const_iterator position, iterator last);
+void swap(forward_list<T,Allocator>&&);
+
+[..]
+
+// 23.3.3.6 specialized algorithms:
+template <class T, class Allocator>
+void swap(forward_list<T,Allocator>& x, forward_list<T,Allocator>& y);
+template <class T, class Allocator>
+void swap(forward_list<T,Allocator>&& x, forward_list<T,Allocator>& y);
+template <class T, class Allocator>
+void swap(forward_list<T,Allocator>& x, forward_list<T,Allocator>&& y);
+
            
+
+
            20. 
+
+
          20. 
+
            
+Change 23.3.3.6 [forwardlist.spec] as indicated:
+
            
+
+
            template <class T, class Allocator>
+void swap(forward_list<T,Allocator>& x, forward_list<T,Allocator>& y);
+template <class T, class Allocator>
+void swap(forward_list<T,Allocator>&& x, forward_list<T,Allocator>& y);
+template <class T, class Allocator>
+void swap(forward_list<T,Allocator>& x, forward_list<T,Allocator>&& y);
+
            
+
+
            21. 
+
+
          21. 
+
            
+Change 23.3.4 [list]/2 as indicated:
+
            
+
+
            iterator erase(const_iterator position);
+iterator erase(const_iterator position, const_iterator last);
+void swap(list<T,Allocator>&&);
+void clear();
+
+[..]
+
+// specialized algorithms:
+template <class T, class Allocator>
+void swap(list<T,Allocator>& x, list<T,Allocator>& y);
+template <class T, class Allocator>
+void swap(list<T,Allocator>&& x, list<T,Allocator>& y);
+template <class T, class Allocator>
+void swap(list<T,Allocator>& x, list<T,Allocator>&& y);
+
            
+
+
            22. 
+
+
          22. 
+
            
+Change 23.3.4.5 [list.special] as indicated:
+
            
+
+
            template <class T, class Allocator>
+void swap(list<T,Allocator>& x, list<T,Allocator>& y);
+template <class T, class Allocator>
+void swap(list<T,Allocator>&& x, list<T,Allocator>& y);
+template <class T, class Allocator>
+void swap(list<T,Allocator>& x, list<T,Allocator>&& y);
+
            
+
+
            23. 
+
+
          23. 
+
            
+Change 23.3.5.1.1 [queue.defn] as indicated:
+
            
+
+
            void swap(queue&& q) { c.swap(q.c); }
+
+[..]
+
+template <class T, class Container>
+void swap(queue<T, Container>& x, queue<T, Container>& y);
+template <class T, class Container>
+void swap(queue<T, Container>&& x, queue<T, Container>& y);
+template <class T, class Container>
+void swap(queue<T, Container>& x, queue<T, Container>&& y);
+
            
+
+
            24. 
+
+
          24. 
+
            
+Change 23.3.5.1.3 [queue.special] as indicated:
+
            
+
+
            template <class T, class Container>
+void swap(queue<T, Container>& x, queue<T, Container>& y);
+template <class T, class Container>
+void swap(queue<T, Container>&& x, queue<T, Container>& y);
+template <class T, class Container>
+void swap(queue<T, Container>& x, queue<T, Container>&& y);
+
            
+
+
            25. 
+
+
          25. 
+
            
+Change 23.3.5.2 [priority.queue]/1 as indicated:
+
            
+
+
            void swap(priority_queue&&);
+
+// no equality is provided
+template <class T, class Container, class Compare>
+void swap(priority_queue<T, Container, Compare>& x, priority_queue<T, Container, Compare>& y);
+template <class T, class Container, class Compare>
+void swap(priority_queue<T, Container, Compare>&& x, priority_queue<T, Container, Compare>& y);
+template <class T, class Container, class Compare>
+void swap(priority_queue<T, Container, Compare>& x, priority_queue<T, Container, Compare>&& y);
+
            
+
+
            26. 
+
+
          26. 
+
            
+Change 23.3.5.2.3 [priqueue.special] as indicated:
+
            
+
+
            template <class T, class Container, Compare>
+void swap(priority_queue<T, Container, Compare>& x, priority_queue<T, Container, Compare>& y);
+template <class T, class Container, Compare>
+void swap(priority_queue<T, Container, Compare>&& x, priority_queue<T, Container, Compare>& y);
+template <class T, class Container, Compare>
+void swap(priority_queue<T, Container, Compare>& x, priority_queue<T, Container, Compare>&& y);
+
            
+
+
            27. 
+
+
          27. 
+
            
+Change 23.3.5.3.1 [stack.defn] as indicated:
+
            
+
+
            void swap(stack&& s) { c.swap(s.c); }
+
+[..]
+
+template <class T, class Allocator>
+void swap(stack<T,Allocator>& x, stack<T,Allocator>& y);
+template <class T, class Allocator>
+void swap(stack<T,Allocator>&& x, stack<T,Allocator>& y);
+template <class T, class Allocator>
+void swap(stack<T,Allocator>& x, stack<T,Allocator>&& y);
+
            
+
+
+
            28. 
+
+
          28. 
+
            
+Change 23.3.5.3.3 [stack.special] as indicated:
+
            
+
+
            template <class T, class Container>
+void swap(stack<T, Container>& x, stack<T, Container>& y);
+template <class T, class Container>
+void swap(stack<T, Container>&& x, stack<T, Container>& y);
+template <class T, class Container>
+void swap(stack<T, Container>& x, stack<T, Container>&& y);
+
            
+
+
            29. 
+
+
          29. 
+
            
+Change 23.3.6 [vector]/2 as indicated:
+
            
+
+
            void swap(vector<T,Allocator>&&);
+void clear();
+
+[..]
+
+// specialized algorithms:
+template <class T, class Allocator>
+void swap(vector<T,Allocator>& x, vector<T,Allocator>& y);
+template <class T, class Allocator>
+void swap(vector<T,Allocator>&& x, vector<T,Allocator>& y);
+template <class T, class Allocator>
+void swap(vector<T,Allocator>& x, vector<T,Allocator>&& y);
+
            
+
+
            30. 
+
+
          30. 
+
            
+Change 23.3.6.2 [vector.capacity] before p. 8 as indicated:
+
            
+
+
            void swap(vector<T,Allocator>&& x);
+
            
+
+
            31. 
+
+
          31. 
+
            
+Change 23.3.6.5 [vector.special] as indicated:
+
            
+
+
            template <class T, class Allocator>
+void swap(vector<T,Allocator>& x, vector<T,Allocator>& y);
+template <class T, class Allocator>
+void swap(vector<T,Allocator>&& x, vector<T,Allocator>& y);
+template <class T, class Allocator>
+void swap(vector<T,Allocator>& x, vector<T,Allocator>&& y);
+
            
+
+
            32. 
+
+
          32. 
+
            
+Change 23.3.7 [vector.bool]/1 as indicated:
+
            
+
+
            iterator erase(const_iterator first, const_iterator last);
+void swap(vector<bool,Allocator>&&);
+static void swap(reference x, reference y);
+
            
+
+
            33. 
+
+
          33. 
+
            
+Change 23.4 [associative]/1, header <map> synopsis as indicated:
+
            
+
+
            template <class Key, class T, class Compare, class Allocator>
+void swap(map<Key,T,Compare,Allocator>& x, map<Key,T,Compare,Allocator>& y);
+template <class Key, class T, class Compare, class Allocator>
+void swap(map<Key,T,Compare,Allocator&& x, map<Key,T,Compare,Allocator>& y);
+template <class Key, class T, class Compare, class Allocator>
+void swap(map<Key,T,Compare,Allocator& x, map<Key,T,Compare,Allocator>&& y);
+
+[..]
+
+template <class Key, class T, class Compare, class Allocator>
+void swap(multimap<Key,T,Compare,Allocator>& x, multimap<Key,T,Compare,Allocator>& y);
+template <class Key, class T, class Compare, class Allocator>
+void swap(multimap<Key,T,Compare,Allocator&& x, multimap<Key,T,Compare,Allocator>& y);
+template <class Key, class T, class Compare, class Allocator>
+void swap(multimap<Key,T,Compare,Allocator& x, multimap<Key,T,Compare,Allocator>&& y);
+
            
+
+
            34. 
+
+
          34. 
+
            
+Change 23.4 [associative]/1, header <set> synopsis as indicated:
+
            
+
+
            template <class Key, class Compare, class Allocator>
+void swap(set<Key,Compare,Allocator>& x, set<Key,Compare,Allocator>& y);
+template <class Key, class T, class Compare, class Allocator>
+void swap(set<Key,T,Compare,Allocator&& x, set<Key,T,Compare,Allocator>& y);
+template <class Key, class T, class Compare, class Allocator>
+void swap(set<Key,T,Compare,Allocator& x, set<Key,T,Compare,Allocator>&& y);
+
+[..]
+
+template <class Key, class Compare, class Allocator>
+void swap(multiset<Key,Compare,Allocator>& x, multiset<Key,Compare,Allocator>& y);
+template <class Key, class T, class Compare, class Allocator>
+void swap(multiset<Key,T,Compare,Allocator&& x, multiset<Key,T,Compare,Allocator>& y);
+template <class Key, class T, class Compare, class Allocator>
+void swap(multiset<Key,T,Compare,Allocator& x, multiset<Key,T,Compare,Allocator>&& y);
+
            
+
+
            35. 
+
+
          35. 
+
            
+Change 23.4.1 [map]/2 as indicated:
+
            
+
+
            iterator erase(const_iterator first, const_iterator last);
+void swap(map<Key,T,Compare,Allocator>&&);
+void clear();
+
+[..]
+
+// specialized algorithms:
+template <class Key, class T, class Compare, class Allocator>
+void swap(map<Key,T,Compare,Allocator>& x, map<Key,T,Compare,Allocator>& y);
+template <class Key, class T, class Compare, class Allocator>
+void swap(map<Key,T,Compare,Allocator&& x, map<Key,T,Compare,Allocator>& y);
+template <class Key, class T, class Compare, class Allocator>
+void swap(map<Key,T,Compare,Allocator& x, map<Key,T,Compare,Allocator>&& y);
+
            
+
+
            36. 
+
+
          36. 
+
            
+Change 23.4.1.5 [map.special] as indicated:
+
            
+
+
            template <class Key, class T, class Compare, class Allocator>
+void swap(map<Key,T,Compare,Allocator>& x, map<Key,T,Compare,Allocator>& y);
+template <class Key, class T, class Compare, class Allocator>
+void swap(map<Key,T,Compare,Allocator>&& x, map<Key,T,Compare,Allocator>& y);
+template <class Key, class T, class Compare, class Allocator>
+void swap(map<Key,T,Compare,Allocator>& x, map<Key,T,Compare,Allocator>&& y);
+
            
+
+
            37. 
+
+
          37. 
+
            
+Change 23.4.2 [multimap]/2 as indicated:
+
            
+
+
            iterator erase(const_iterator first, const_iterator last);
+void swap(multimap<Key,T,Compare,Allocator>&&);
+void clear();
+
+[..]
+
+// specialized algorithms:
+template <class Key, class T, class Compare, class Allocator>
+void swap(multimap<Key,T,Compare,Allocator>& x, multimap<Key,T,Compare,Allocator>& y);
+template <class Key, class T, class Compare, class Allocator>
+void swap(multimap<Key,T,Compare,Allocator&& x, multimap<Key,T,Compare,Allocator>& y);
+template <class Key, class T, class Compare, class Allocator>
+void swap(multimap<Key,T,Compare,Allocator& x, multimap<Key,T,Compare,Allocator>&& y);
+
            
+
+
            38. 
+
+
          38. 
+
            
+Change 23.4.2.4 [multimap.special] as indicated:
+
            
+
+
            template <class Key, class T, class Compare, class Allocator>
+void swap(multimap<Key,T,Compare,Allocator>& x, multimap<Key,T,Compare,Allocator>& y);
+template <class Key, class T, class Compare, class Allocator>
+void swap(multimap<Key,T,Compare,Allocator>&& x, multimap<Key,T,Compare,Allocator>& y);
+template <class Key, class T, class Compare, class Allocator>
+void swap(multimap<Key,T,Compare,Allocator>& x, multimap<Key,T,Compare,Allocator>&& y);
+
            
+
+
            39. 
+
+
          39. 
+
            
+Change 23.4.3 [set]/2 and 23.4.3.2 [set.special] as indicated: (twice!)
+
            
+
+
            // specialized algorithms:
+template <class Key, class Compare, class Allocator>
+void swap(set<Key,Compare,Allocator>& x, set<Key,Compare,Allocator>& y);
+template <class Key, class Compare, class Allocator>
+void swap(set<Key,Compare,Allocator&& x, set<Key,Compare,Allocator>& y);
+template <class Key, class Compare, class Allocator>
+void swap(set<Key,Compare,Allocator& x, set<Key,Compare,Allocator>&& y);
+
            
+
+
            40. 
+
+
          40. 
+
            
+Change 23.4.4 [multiset]/2 as indicated:
+
            
+
+
            iterator erase(const_iterator first, const_iterator last);
+void swap(multiset<Key,Compare,Allocator>&&);
+void clear();
+
+[..]
+
+// specialized algorithms:
+template <class Key, class Compare, class Allocator>
+void swap(multiset<Key,Compare,Allocator>& x, multiset<Key,Compare,Allocator>& y);
+template <class Key, class Compare, class Allocator>
+void swap(multiset<Key,Compare,Allocator&& x, multiset<Key,Compare,Allocator>& y);
+template <class Key, class Compare, class Allocator>
+void swap(multiset<Key,Compare,Allocator& x, multiset<Key,Compare,Allocator>&& y);
+
            
+
+
            41. 
+
+
          41. 
+
            
+Change 23.4.4.2 [multiset.special] as indicated:
+
            
+
+
            template <class Key, class Compare, class Allocator>
+void swap(multiset<Key,Compare,Allocator>& x, multiset<Key,Compare,Allocator>& y);
+template <class Key, class Compare, class Allocator>
+void swap(multiset<Key,Compare,Allocator>&& x, multiset<Key,Compare,Allocator>& y);
+template <class Key, class Compare, class Allocator>
+void swap(multiset<Key,Compare,Allocator>& x, multiset<Key,Compare,Allocator>&& y);
+
            
+
+
            42. 
+
          
+
+
+
+
+
+
          
+
          1235. Issue with C++0x random number proposal
          
+
          Section: 26.5.2.5 [rand.concept.dist] Status: NAD Future
+ Submitter: Matthias Troyer Opened: 2009-10-12  Last modified: 2009-10-26
          
+
          View all issues with NAD Future status.
          
+
          Discussion:
          
+
          
+There exist optimized, vectorized vendor libraries for the creation of
+random number generators, such as Intel's MKL [1] and AMD's ACML [2]. In
+timing tests we have seen a performance gain of a factor of up to 80
+(eighty) compared to a pure C++ implementation (in Boost.Random) when
+using these generator to generate a sequence of normally distributed
+random numbers. In codes dominated by the generation of random numbers
+(we have application codes where random number generation is more than
+50% of the CPU time) this factor 80 is very significant.
+
          
+
+
          
+To make use of these vectorized generators, we use a C++ class modeling
+the RandomNumberEngine concept and forwarding the generation of random
+numbers to those optimized generators. For example:
+
          
+
+
          namespace mkl {
+ class mt19937 {.... };
+}
+
          
+
+
          
+For the generation of random variates we also want to dispatch to
+optimized vectorized functions in the MKL or ACML libraries. See this
+example:
+
          
+
+
          mkl::mt19937 eng;
+std::normal_distribution<double> dist;
+
+double n = dist(eng);
+
          
+
+
          
+Since the variate generation is done through the operator() of the
+distribution there is no customization point to dispatch to Intel's or
+AMD's optimized functions to generate normally distributed numbers based
+on the mt19937 generator. Hence, the performance gain of 80 cannot be
+achieved.
+
          
+
+
          
+Contrast this with TR1:
+
          
+
+
          mkl::mt19937 eng;
+std::tr1::normal_distribution<double> dist;
+std::tr1::variate_generator<mkl::mt19937,std::tr1::normal_distribution<double> > rng(eng,dist);
+double n = rng();
+
          
+
+
          
+This - admittedly much uglier from an aestethic point of view - design
+allowed optimization by specializing the variate_generator template for
+mkl::mt19937:
+
          
+
+
          namespace std { namespace tr1 {
+
+template<>
+class variate_generator<mkl::mt19937,std::tr1::normal_distribution<double> > { .... };
+
+} }
+
          
+
+
          
+A similar customization point is missing in the C++0x design and
+prevents the optimized vectorized version to be used.
+
          
+
+
          
+Suggested resolution:
+
          
+
+
          
+Add a customization point to the distribution concept. Instead of the
+variate_generator template this can be done through a call to a
+free function generate_variate found by ADL instead of
+operator() of the distribution:
+
          
+
+
          template <RandomNumberDistribution, class RandomNumberEngine>
+typename RandomNumberDistribution ::result_type
+generate_variate(RandomNumberDistribution const& dist, RandomNumberEngine& eng);
+
          
+
+
          
+This function can be overloaded for optimized enginges like
+mkl::mt19937.
+
          
+
+
          [
+2009-10 Santa Cruz:
+]
          
+
+
+
          
+NAD Future.  No time to add this feature for C++0X.
+
          
+
+
+
+
          Proposed resolution:
          
+
+
+
+
+
+
          
+
          1236. reserved identifiers in programs not using the library
          
+
          Section: 17 [library] Status: NAD
+ Submitter: Sean Hunt Opened: 2009-10-13  Last modified: 2009-10-20
          
+
          View other active issues in [library].
          
+
          View all other issues in [library].
          
+
          View all issues with NAD status.
          
+
          Discussion:
          
+
          
+I wasn't sure whether to consider this a library or a language issue,
+because the issue is I think it's incorrectly categorized as being part
+of the library, so I thought I'd send a message to both of you and let
+you sort it out.
+
          
+
+
          
+Most reserved identifiers are treated as unilaterally available to the
+implementation, such as to implement language extensions, or provide
+macros documenting its functionality. However, the requirements for
+reserved identifers are in 17.6.3.3 [reserved.names], which are a
+subsection of 17.6.3 [constraints]. 17.6.3.1 [constraints.overview] appears only to apply to "C++ programs
+that use the facilities of the C++ standard library", meaning that, in
+theory, all implementations are erroneous in having any non-standard
+identifiers predefined for programs that do not, at some point, include
+a standard library header.
+
          
+
+
          Furthermore, it's unclear whether the use of certain identifiers is
+UB
+or results in an ill-formed program. In particular, 17.6.3.3.1
+[macro.names] uses a "shall not", where 17.6.3.3.2 [global.names] says
+that names are "reserved to the
+implementation". 17.6.3.3 [reserved.names] seems only to cover the
+instance of a name being described as "reserved", so are
+implementations
+required to diagnose a program that performs, as an example, "#undef
+get"?
+
          
+
+
          [
+2009 Santa Cruz:
+]
          
+
+
+
          
+Move to NAD. There may in theory be multiple interpretations possible,
+but there's no evidence that this causes any genuine problems or
+uncertainty about what implementations are allowed to do. We do not
+believe this rises to the level of a defect.
+
          
+
+
+
+
          Proposed resolution:
          
+
+
+
+
+
+
          
+
          1242. Enable SCARY iterators
          
+
          Section: 23 [containers] Status: NAD Future
+ Submitter: Herb Sutter Opened: 2009-10-21  Last modified: 2009-10-21
          
+
          View other active issues in [containers].
          
+
          View all other issues in [containers].
          
+
          View all issues with NAD Future status.
          
+
          Discussion:
          
+
          
+See
+N2980.
+
          
+
+
+
          Proposed resolution:
          
+
+
+
+
+
+
          
+
          1243. Missing operator+= (initializer_list<T>) for valarray
          
+
          Section: 26.6.2.6 [valarray.cassign] Status: NAD
+ Submitter: Daniel Krügler Opened: 2009-10-22  Last modified: 2009-10-26
          
+
          View all other issues in [valarray.cassign].
          
+
          View all issues with NAD status.
          
+
          Discussion:
          
+
          Addresses JP 64
          
+
+
          
+During the additions of initializer_list overloads
+basic_string added
+
          
+
+
          basic_string& operator+=(initializer_list<charT>);
+
          
+
+
          
+but
+
          
+
+
          valarray<T>& operator+= (initializer_list<T>);
+
          
+
+
          
+was not defined.
+
          
+
+
          [
+Daniel adds on opening:
+]
          
+
+
+
          
+Recommend NAD. The operator+= overload of basic_string
+behaves as-if calling append, which is completely different in
+meaning as the existing operator+= overloads in
+valarray which just sum the value or values to the existing
+elements. The suggestion to add a corresponding append function to
+valarray was not considered as appropriate and the request was
+withdrawn (c++std-lib-24968).
+
          
+
+
          [
+2009-10 Santa Cruz:
+]
          
+
+
+
          
+Mark as NAD.  Request has been withdrawn by NB.
+
          
+
+
+
+
          Proposed resolution:
          
+
          
+Add to 26.6.2.6 [valarray.cassign]:
+
          
+
+
          valarray<T>& operator+= (initializer_list<T>);
+
          
+
+
+
+
+
+
          
+
          1248. Equality comparison for unordered containers
          
+
          Section: 23.5 [unord] Status: NAD Future
+ Submitter: Herb Sutter Opened: 2009-10-25  Last modified: 2009-10-25
          
+
          View all other issues in [unord].
          
+
          View all issues with NAD Future status.
          
+
          Discussion:
          
+
          
+See
+N2986.
+
          
+
+
+
          Proposed resolution:
          
+
+
+
+
+
 
\ No newline at end of file
diff --git a/libstdc++-v3/doc/html/ext/lwg-defects.html b/libstdc++-v3/doc/html/ext/lwg-defects.html
index 17eb1ecfa8f..0201cfbd739 100644
--- a/libstdc++-v3/doc/html/ext/lwg-defects.html
+++ b/libstdc++-v3/doc/html/ext/lwg-defects.html
@@ -7,6 +7,14 @@
 
@@ -14,11 +22,11 @@ del {background-color:#FFA0A0}
 
-
+
-
+
@@ -29,7 +37,7 @@ del {background-color:#FFA0A0}
 
          
 
          
 Doc. no.N2941=09-0131N3012=09-0202
 
          
 
          
 Date:2009-08-022009-11-08
 
          
 
          
 Project:Howard Hinnant <howard.hinnant@gmail.com>
 
          
 
          
-
          C++ Standard Library Defect Report List (Revision R66)
          
+
          C++ Standard Library Defect Report List (Revision R68)
          
 
   
          Reference ISO/IEC IS 14882:2003(E)
          
   
          Also see:
          
@@ -51,6 +59,76 @@ del {background-color:#FFA0A0}
 
 
          Revision History
          
 
@@ -112,24 +190,24 @@ del {background-color:#FFA0A0}
 
        3. 1143 issues total, up by 32.
          4. 
 
          4. 
 
        4. Details:
          5. 
 
 
@@ -142,7 +220,7 @@ del {background-color:#FFA0A0}
 
        5. 1111 issues total, up by 19.
          6. 
 
 
        6. Details:
          7. 
@@ -159,9 +237,9 @@ del {background-color:#FFA0A0}
 
        7. Details:
          8. 
 
@@ -192,7 +270,7 @@ del {background-color:#FFA0A0}
 
        8. 982 issues total, up by 44.
          9. 
 
 
        9. Details:
          10. 
 
 
@@ -205,7 +283,7 @@ del {background-color:#FFA0A0}
 
        10. 938 issues total, up by 20.
          11. 
 
 
        11. Details:
          12. 
 
 
@@ -219,28 +297,28 @@ del {background-color:#FFA0A0}
 
 
        12. Details:
          13. 
 
@@ -254,7 +332,7 @@ del {background-color:#FFA0A0}
 
        13. 878 issues total, up by 9.
          14. 
 
 
        14. Details:
          15. 
 
 
@@ -285,21 +363,21 @@ del {background-color:#FFA0A0}
 
 
        15. Details:
          16. 
 
        16. Details:
          17. 
 
@@ -331,7 +409,7 @@ del {background-color:#FFA0A0}
 
        17. Details:
          18. 
 
        18. Details:
            
 
          • Added the following New issues: 755, 756, 757, 758, 759, 760, 761, 762, 763, 764.
            • 
-
          • Changed the following issues from NAD to Open: 463.
            • 
+
          • Changed the following issues from NAD to Open: 463.
            • 
 
          • Changed the following issues from Pending WP to WP: 607, 608, 654, 655, 677, 682.
            • 
 
          19. 
 
@@ -402,7 +480,7 @@ del {background-color:#FFA0A0}
 
        19. Changed the following issues from NAD Future to Dup: 77, 350.
          20. 
 
        20. Changed the following issues from New to NAD: 639, 657, 663.
          21. 
 
        21. Changed the following issues from Open to NAD: 548.
          22. 
-
        22. Changed the following issues from New to Open: 546, 550, 564, 565, 573, 585, 588, 627, 629, 630, 632, 635, 653, 659, 667, 668, 669, 670, 671, 673, 686, 704, 707, 708.
          23. 
+
        23. Changed the following issues from New to Open: 546, 550, 564, 565, 573, 585, 588, 627, 629, 630, 632, 635, 653, 659, 667, 668, 669, 670, 671, 673, 686, 704, 707, 708.
          24. 
 
        24. Changed the following issues from New to Pending NAD Editorial: 393, 592.
          25. 
 
        25. Changed the following issues from New to Pending WP: 607, 608, 654, 655, 677, 682.
          26. 
 
        26. Changed the following issues from New to Ready: 561, 562, 563, 567, 581, 595, 620, 621, 622, 623, 624, 661, 664, 665, 666, 674, 675, 676, 679, 687, 688, 689, 693, 694, 695, 700, 703, 705, 706.
          27. 
@@ -423,7 +501,7 @@ del {background-color:#FFA0A0}
 
        27. 723 issues total, up by 15.
          28. 
 
 
        28. Details:
          29. 
 
 
@@ -463,7 +541,7 @@ del {background-color:#FFA0A0}
 
        29. 696 issues total, up by 20.
          30. 
 
 
        30. Details:
          31. 
 
        31. Details:
          32. 
 
        32. Details:
          33. 
 
@@ -525,7 +603,7 @@ del {background-color:#FFA0A0}
 
        33. 619 issues total, up by 10.
          34. 
 
 
        34. Details:
          35. 
 
 
@@ -557,7 +635,7 @@ del {background-color:#FFA0A0}
 
        35. 592 issues total, up by 5.
          36. 
 
 
        36. Details:
          37. 
 
 
@@ -570,7 +648,7 @@ del {background-color:#FFA0A0}
 
        37. 587 issues total, up by 13.
          38. 
 
 
        38. Details:
          39. 
@@ -587,7 +665,7 @@ del {background-color:#FFA0A0}
 
        39. Details:
          40. 
 
        40. Details:
          41. 
@@ -618,7 +696,7 @@ del {background-color:#FFA0A0}
 
        41. 535 issues total.
          42. 
 
 
        42. Details:
          43. 
 
 
@@ -627,7 +705,7 @@ del {background-color:#FFA0A0}
 Added new issues 526-528.
 Moved issues 280, 461, 464, 465, 467, 468, 474, 496 from Ready to WP as per the vote from Mont Tremblant.
 Moved issues 247, 294, 342, 362, 369, 371, 376, 384, 475, 478, 495, 497 from Review to Ready.
-Moved issues 498, 504, 506, 509, 510, 511, 512, 513, 514 from New to Open.
+Moved issues 498, 504, 506, 509, 510, 511, 512, 513, 514 from New to Open.
 Moved issues 505, 507, 508, 519 from New to Ready.
 Moved issue 500 from New to NAD.
 Moved issue 518 from New to Review.
@@ -639,7 +717,7 @@ Added new issues 498-503.
+Added new issues 498-503.
 
 
        43. R36: 
 2005-04 post-Lillehammer mailing. All issues in "ready" status except
@@ -663,7 +741,7 @@ new issues 463-478.
+new issues 463-478.
 
          44. 
 
        44. R30: 
 Post-Sydney mailing: reflects decisions made at the Sydney meeting.
@@ -678,7 +756,7 @@ Post-Kona mailing: reflects decisions made at the Kona meeting.
 Added new issues 432-440.
 
          45. 
 
        45. R27: 
-Pre-Kona mailing.  Added new issues 404-431.
+Pre-Kona mailing.  Added new issues 404-431.
 
          46. 
 
        46. R26: 
 Post-Oxford mailing: reflects decisions made at the Oxford meeting.
@@ -1302,7 +1380,7 @@ supporting to the proposed resolution.
          
 
 
          
 
          11. Bitset minor problems
          
-
          Section: 20.3.6 [template.bitset] Status: TC1
+
          Section: 20.3.7 [template.bitset] Status: TC1
  Submitter: Matt Austern Opened: 1998-01-22  Last modified: 2008-09-26
          
 
          View other active issues in [template.bitset].
          
 
          View all other issues in [template.bitset].
          
@@ -1323,7 +1401,7 @@ go in the Effects clause.
          
 
          Proposed resolution:
          
 
          ITEMS 1 AND 2:
          
 
          
-In the bitset synopsis (20.3.6 [template.bitset]), 
+In the bitset synopsis (20.3.7 [template.bitset]), 
 replace the member function 
          
 
          
     reference operator[](size_t pos);
          
@@ -1333,7 +1411,7 @@ with the two member functions
          
     bool operator[](size_t pos) const; 
          
     reference operator[](size_t pos); 
          
 
          
-Add the following text at the end of 20.3.6.2 [bitset.members], 
+Add the following text at the end of 20.3.7.2 [bitset.members], 
 immediately after paragraph 45:
          
 
 
          
@@ -2251,6 +2329,7 @@ string_type s = val ? np.truename() : np.falsename(); 
        
 
        35. No manipulator unitbuf in synopsis
        
 
        Section: 27.5 [iostreams.base] Status: TC1
  Submitter: Nathan Myers Opened: 1998-08-06  Last modified: 2008-09-26
        
+
        View all other issues in [iostreams.base].
        
 
        View all issues with TC1 status.
        
 
        Discussion:
        
 
        In 27.5.5.1 [fmtflags.manip], we have a definition for a manipulator
@@ -2811,13 +2890,13 @@ change uses of == and != to use the traits members instead. 
        
 
 
        
 
        46. Minor Annex D errors
        
-
        Section: D.7 [depr.str.strstreams] Status: TC1
+
        Section: D.8 [depr.str.strstreams] Status: TC1
  Submitter: Brendan Kehoe Opened: 1998-06-01  Last modified: 2008-09-26
        
 
        View all issues with TC1 status.
        
 
        Discussion:
        See lib-6522 and edit-814.
        
 
 
        Proposed resolution:
        
-
        Change D.7.1 [depr.strstreambuf] (since streambuf is a typedef of
+
        Change D.8.1 [depr.strstreambuf] (since streambuf is a typedef of
 basic_streambuf<char>) from:
        
 
 
                 virtual streambuf<char>* setbuf(char* s, streamsize n);
        
@@ -2826,7 +2905,7 @@ basic_streambuf<char>) from:
        
 
 
                 virtual streambuf* setbuf(char* s, streamsize n);
        
 
-
        In D.7.4 [depr.strstream] insert the semicolon now missing after
+
        In D.8.4 [depr.strstream] insert the semicolon now missing after
 int_type:
        
 
 
             namespace std {
@@ -3199,7 +3278,7 @@ stream position" should not be changed:
        
 
        
   
        27.8.1.4 [stringbuf.virtuals], paragraph 14
        
   27.9.1.5 [filebuf.virtuals], paragraph 14
        
-  D.7.1.3 [depr.strstreambuf.virtuals], paragraph 17
+  D.8.1.3 [depr.strstreambuf.virtuals], paragraph 17
   
        
 
        
 
@@ -3228,11 +3307,11 @@ returns an invalid stream position (_lib.iostreams.definitions_)"
 to "Otherwise returns pos_type(off_type(-1))"
 
        
 
-
        In D.7.1.3 [depr.strstreambuf.virtuals], paragraph 15, change "the object
+
        In D.8.1.3 [depr.strstreambuf.virtuals], paragraph 15, change "the object
 stores an invalid stream position" to "the return value is
 pos_type(off_type(-1))" 
        
 
-
        In D.7.1.3 [depr.strstreambuf.virtuals], paragraph 18, change "the object
+
        In D.8.1.3 [depr.strstreambuf.virtuals], paragraph 18, change "the object
 stores an invalid stream position" to "the return value is
 pos_type(off_type(-1))"
        
 
@@ -3788,7 +3867,7 @@ elaboration of the first. 
        
 
 
        
 
        66. Strstreambuf::setbuf
        
-
        Section: D.7.1.3 [depr.strstreambuf.virtuals] Status: TC1
+
        Section: D.8.1.3 [depr.strstreambuf.virtuals] Status: TC1
  Submitter: Matt Austern Opened: 1998-08-18  Last modified: 2008-09-26
        
 
        View all other issues in [depr.strstreambuf.virtuals].
        
 
        View all issues with TC1 status.
        
@@ -3801,7 +3880,7 @@ strstreambuf. 
        
 
 
 
        Proposed resolution:
        
-
        D.7.1.3 [depr.strstreambuf.virtuals], paragraph 19, replace the setbuf effects
+
        D.8.1.3 [depr.strstreambuf.virtuals], paragraph 19, replace the setbuf effects
 clause which currently says "Performs an operation that is
 defined separately for each class derived from strstreambuf"
 with:
        
@@ -3857,7 +3936,6 @@ item from:
        
 
        69. Must elements of a vector be contiguous?
        
 
        Section: 23.3.6 [vector] Status: TC1
  Submitter: Andrew Koenig Opened: 1998-07-29  Last modified: 2008-09-26
        
-
        View other active issues in [vector].
        
 
        View all other issues in [vector].
        
 
        View all issues with TC1 status.
        
 
        Discussion:
        
@@ -3892,7 +3970,7 @@ directly defined in the standard.  Discussion included:
        
     already used for valarray (26.6.2.3 [valarray.access]).
        3. 
   
      3. There is no need to explicitly consider a user-defined operator& 
     because elements must be copyconstructible (23.2 [container.requirements] para 3) 
-    and copyconstructible (X [utility.arg.requirements]) specifies
+    and copyconstructible (20.2.1 [utility.arg.requirements]) specifies
     requirements for operator&.
        4. 
   
      4. There is no issue of one-past-the-end because of language rules.
        5. 
 
@@ -4498,12 +4576,12 @@ objects by algorithms is unspecified".  Consider placing in
 
 
        
 
        98. Input iterator requirements are badly written
        
-
        Section: 24.2.2 [input.iterators] Status: CD1
+
        Section: 24.2.1 [input.iterators] Status: CD1
  Submitter: AFNOR Opened: 1998-10-07  Last modified: 2008-09-26
        
 
        View all other issues in [input.iterators].
        
 
        View all issues with CD1 status.
        
 
        Discussion:
        
-
        Table 72 in 24.2.2 [input.iterators] specifies semantics for
+
        Table 72 in 24.2.1 [input.iterators] specifies semantics for
 *r++ of:
        
 
 
           { T tmp = *r; ++r; return tmp; }
        
@@ -4522,7 +4600,7 @@ problem.
        
 
 
 
        Proposed resolution:
        
-
        In Table 72 in 24.2.2 [input.iterators], change the return type
+
        In Table 72 in 24.2.1 [input.iterators], change the return type
 for *r++ from T to "convertible to T".
        
 
 
@@ -4554,6 +4632,7 @@ for *r++ from T to "convertible to T".
        
 
        103. set::iterator is required to be modifiable, but this allows modification of keys
        
 
        Section: 23.2.4 [associative.reqmts] Status: CD1
  Submitter: AFNOR Opened: 1998-10-07  Last modified: 2008-09-26
        
+
        View other active issues in [associative.reqmts].
        
 
        View all other issues in [associative.reqmts].
        
 
        View all issues with CD1 status.
        
 
        Discussion:
        
@@ -4736,7 +4815,7 @@ returned by what().
 
 
        
 
        109. Missing binders for non-const sequence elements
        
-
        Section: D.8 [depr.lib.binders] Status: CD1
+
        Section: D.9 [depr.lib.binders] Status: CD1
  Submitter: Bjarne Stroustrup Opened: 1998-10-07  Last modified: 2008-09-26
        
 
        View all other issues in [depr.lib.binders].
        
 
        View all issues with CD1 status.
        
@@ -4817,7 +4896,7 @@ public:
 
        Howard believes there is a flaw in this resolution.
 See c++std-lib-9127.  We may need to reopen this issue.
        
 
-
        In D.8 [depr.lib.binders] in the declaration of binder1st after:
        
+
        In D.9 [depr.lib.binders] in the declaration of binder1st after:
        
 
        
   
        typename Operation::result_type
        
    operator()(const typename Operation::second_argument_type& x) const;
        
@@ -4827,7 +4906,7 @@ See c++std-lib-9127.  We may need to reopen this issue.
        
   
        typename Operation::result_type
        
    operator()(typename Operation::second_argument_type& x) const;
        
 
        
-
        In D.8 [depr.lib.binders] in the declaration of binder2nd after:
        
+
        In D.9 [depr.lib.binders] in the declaration of binder2nd after:
        
 
        
   
        typename Operation::result_type
        
    operator()(const typename Operation::first_argument_type& x) const;
        
@@ -4953,7 +5032,7 @@ likely to fail.
        
 
 
        
 
        115. Typo in strstream constructors
        
-
        Section: D.7.4.1 [depr.strstream.cons] Status: TC1
+
        Section: D.8.4.1 [depr.strstream.cons] Status: TC1
  Submitter: Steve Clamage Opened: 1998-11-02  Last modified: 2008-09-26
        
 
        View all issues with TC1 status.
        
 
        Discussion:
        
@@ -4975,7 +5054,7 @@ the append bit is set.
        
 
 
 
        Proposed resolution:
        
-
        In D.7.3.1 [depr.ostrstream.cons] paragraph 2 and D.7.4.1 [depr.strstream.cons]
+
        In D.8.3.1 [depr.ostrstream.cons] paragraph 2 and D.8.4.1 [depr.strstream.cons]
 paragraph 2, change the first condition to (mode&app)==0
 and the second condition to (mode&app)!=0.
        
 
@@ -5176,12 +5255,12 @@ operator>>(int& val);
      
 
 
      
 
      119. Should virtual functions be allowed to strengthen the exception specification?
      
-
      Section: 17.6.4.10 [res.on.exception.handling] Status: TC1
+
      Section: 17.6.4.11 [res.on.exception.handling] Status: TC1
  Submitter: Judy Ward Opened: 1998-12-15  Last modified: 2008-09-26
      
 
      View all other issues in [res.on.exception.handling].
      
 
      View all issues with TC1 status.
      
 
      Discussion:
      
-
      Section 17.6.4.10 [res.on.exception.handling] states: 
      
+
      Section 17.6.4.11 [res.on.exception.handling] states: 
      
 
 
      "An implementation may strengthen the exception-specification
 for a function by removing listed exceptions." 
      
@@ -5205,7 +5284,7 @@ public:
 
 
 
      Proposed resolution:
      
-
      Change Section 17.6.4.10 [res.on.exception.handling] from:
      
+
      Change Section 17.6.4.11 [res.on.exception.handling] from:
      
 
 
           "may strengthen the
 exception-specification for a function"
      
@@ -5574,7 +5653,7 @@ latter appears to be correct. 
      
 
 
      
 
      127. auto_ptr<> conversion issues
      
-
      Section: D.9.1 [auto.ptr] Status: TC1
+
      Section: D.10.1 [auto.ptr] Status: TC1
  Submitter: Greg Colvin Opened: 1999-02-17  Last modified: 2008-09-26
      
 
      View all other issues in [auto.ptr].
      
 
      View all issues with TC1 status.
      
@@ -5688,6 +5767,7 @@ stream state in case of failure.
      
 
      130. Return type of container::erase(iterator) differs for associative containers
      
 
      Section: 23.2.4 [associative.reqmts], 23.2.3 [sequence.reqmts] Status: CD1
  Submitter: Andrew Koenig Opened: 1999-03-02  Last modified: 2009-05-01
      
+
      View other active issues in [associative.reqmts].
      
 
      View all other issues in [associative.reqmts].
      
 
      View all issues with CD1 status.
      
 
      Duplicate of: 451
      
@@ -5979,6 +6059,7 @@ in the standard.
      
 
      139. Optional sequence operation table description unclear
      
 
      Section: 23.2.3 [sequence.reqmts] Status: TC1
  Submitter: Andrew Koenig Opened: 1999-03-30  Last modified: 2008-09-26
      
+
      View other active issues in [sequence.reqmts].
      
 
      View all other issues in [sequence.reqmts].
      
 
      View all issues with TC1 status.
      
 
      Discussion:
      
@@ -6042,7 +6123,7 @@ proposed resolution.]
      
 
 
      
 
      142. lexicographical_compare complexity wrong
      
-
      Section: 25.5.8 [alg.lex.comparison] Status: TC1
+
      Section: 25.4.8 [alg.lex.comparison] Status: TC1
  Submitter: Howard Hinnant Opened: 1999-06-20  Last modified: 2008-09-26
      
 
      View all issues with TC1 status.
      
 
      Discussion:
      
@@ -6060,7 +6141,7 @@ right! (and Matt states this complexity in his book)
      
 
 
 
      Proposed resolution:
      
-
      Change 25.5.8 [alg.lex.comparison] complexity to:
      
+
      Change 25.4.8 [alg.lex.comparison] complexity to:
      
     
      
     At most 2*min((last1 - first1), (last2 - first2))
     applications of the corresponding comparison.
@@ -6312,9 +6393,437 @@ two places:
      
 
 
 
+
      
+
      149. Insert should return iterator to first element inserted
      
+
      Section: 23.2.3 [sequence.reqmts] Status: WP
+ Submitter: Andrew Koenig Opened: 1999-06-28  Last modified: 2009-10-26
      
+
      View other active issues in [sequence.reqmts].
      
+
      View all other issues in [sequence.reqmts].
      
+
      View all issues with WP status.
      
+
      Discussion:
      
+
      Suppose that c and c1 are sequential containers and i is an
+iterator that refers to an element of c.  Then I can insert a copy of
+c1's elements into c ahead of element i by executing 
      
+
+
      
+
+
      c.insert(i, c1.begin(), c1.end());
      
+
+
      
+
+
      If c is a vector, it is fairly easy for me to find out where the
+newly inserted elements are, even though i is now invalid: 
      
+
+
      
+
+
      size_t i_loc = i - c.begin();
+c.insert(i, c1.begin(), c1.end());
      
+
+
      
+
+
      and now the first inserted element is at c.begin()+i_loc and one
+past the last is at c.begin()+i_loc+c1.size().
      
+
      
+But what if c is a list? I can still find the location of one past the
+last inserted element, because i is still valid. To find the location
+of the first inserted element, though, I must execute something like 
      
+
+
      
+
+
      for (size_t n = c1.size(); n; --n)
+   --i;
      
+
+
      
+
+
      because i is now no longer a random-access iterator.
      
+
      
+Alternatively, I might write something like 
      
+
+
      
+
+
      bool first = i == c.begin();
+list<T>::iterator j = i;
+if (!first) --j;
+c.insert(i, c1.begin(), c1.end());
+if (first)
+   j = c.begin();
+else
+   ++j;
      
+
+
      
+
+
      which, although wretched, requires less overhead.
      
+
      
+But I think the right solution is to change the definition of insert
+so that instead of returning void, it returns an iterator that refers
+to the first element inserted, if any, and otherwise is a copy of its
+first argument.  
      
+
+
      [
+Summit:
+]
      
+
+
+
      
+Reopened by Alisdair.
+
      
+
+
      [
+Post Summit Alisdair adds:
+]
      
+
+
+
      
+
      
+In addition to the original rationale for C++03, this change also gives a
+consistent interface for all container insert operations i.e. they all
+return an iterator to the (first) inserted item.
+
      
+
+
      
+Proposed wording provided.
+
      
+
      
+
+
      [
+2009-07 Frankfurt
+]
      
+
+
+
      
+
      
+Q: why isn't this change also proposed for associative containers?
+
      
+
+
      
+A: The returned iterator wouldn't necessarily point to a contiguous range.
+
      
+
+
      
+Moved to Ready.
+
      
+
      
+
+
+
+
      Proposed resolution:
      
+
      
+ Table 83
+change return type from void to iterator for the following rows:
+
      
+
+
      
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
      Table 83 -- Sequence container requirements (in addition to container)
      ExpressionReturn typeAssertion/note pre-/post-condition
      
+a.insert(p,n,t)
+
+void iterator
+
+Inserts n copies of t before p.
+
      
+a.insert(p,i,j)
+
+void iterator
+
+Each iterator in the range [i,j) shall be 
+dereferenced exactly once. 
+pre: i and j are not iterators into a. 
+Inserts copies of elements in [i, j) before p
+
      
+a.insert(p,il)
+
+void iterator
+
+a.insert(p, il.begin(), il.end()).
+
      
+
      
+
+
      
+Add after p6 23.2.3 [sequence.reqmts]:
+
      
+
+
      
+
      -6- ...
      
+
+
      
+The iterator returned from a.insert(p,n,t) points to the copy of the
+first element inserted into a, or p if n == 0.
+
      
+
+
      
+The iterator returned from a.insert(p,i,j) points to the copy of the
+first element inserted into a, or p if i == j.
+
      
+
+
      
+The iterator returned from a.insert(p,il) points to the copy of the
+first element inserted into a, or p if il is empty.
+
      
+
+
      
+
+
      
+p2 23.3.2 [deque] Update class definition, change return type
+from void to iterator:
+
      
+
+
      void iterator insert(const_iterator position, size_type n, const T& x);
+template <class InputIterator>
+  void iterator insert(const_iterator position, InputIterator first, InputIterator last);
+  void iterator insert(const_iterator position, initializer_list<T>);
+
      
+
+
      
+23.3.2.3 [deque.modifiers] change return type from void to iterator on following declarations:
+
      
+
+
        void iterator insert(const_iterator position, size_type n, const T& x);
+template <class InputIterator>
+  void iterator insert(const_iterator position, InputIterator first, InputIterator last);
+
      
+
+
      
+Add the following (missing) declaration
+
      
+
+
      iterator insert(const_iterator position, initializer_list<T>);
+
      
+
+
      
+23.3.3 [forwardlist] Update class definition, change return type
+from void to iterator:
+
      
+
+
      void iterator insert_after(const_iterator position, initializer_list<T> il);
+void iterator insert_after(const_iterator position, size_type n, const T& x);
+template <class InputIterator>
+  void iterator insert_after(const_iterator position, InputIterator first, InputIterator last);
+
      
+
+
      
+p8 23.3.3.4 [forwardlist.modifiers] change return type from void to iterator:
+
      
+
+
      void iterator insert_after(const_iterator position, size_type n, const T& x);
+
      
+
+
      
+Add paragraph:
+
      
+
+
      
+Returns: position.
+
      
+
+
      
+p10 23.3.3.4 [forwardlist.modifiers] change return type from void to iterator:
+
      
+
+
      template <class InputIterator>
+  void iterator insert_after(const_iterator position, InputIterator first, InputIterator last);
+
      
+
+
      
+Add paragraph:
+
      
+
+
      
+Returns: position.
+
      
+
+
      
+p12 23.3.3.4 [forwardlist.modifiers] change return type from void to iterator on following declarations:
+
      
+
+
      void iterator insert_after(const_iterator position, initializer_list<T> il);
+
      
+
+
      
+change return type from void to iterator on following declarations:
+
      
+
+
      
+p2 23.3.4 [list] Update class definition, change return type from void to iterator:
+
      
+
+
      void iterator insert(const_iterator position, size_type n, const T& x);
+
+template <class InputIterator>
+void iterator insert(const_iterator position, InputIterator first, InputIterator last);
+
+void iterator insert(const_iterator position, initializer_list<T>);
+
      
+
+
      
+23.3.4.3 [list.modifiers] change return type from void to iterator on following declarations:
+
      
+
+
      void iterator insert(const_iterator position, size_type n, const T& x);
+
+template <class InputIterator>
+  void iterator insert(const_iterator position, InputIterator first, InputIterator last);
+
      
+
+
      
+Add the following (missing) declaration
+
      
+
+
      iterator insert(const_iterator position, initializer_list<T>);
+
      
+
+
      
+p2 23.3.6 [vector]
+
      
+
+
      
+Update class definition, change return type from void to iterator:
+
      
+
+
      void iterator insert(const_iterator position, T&& x);
+
+void iterator insert(const_iterator position, size_type n, const T& x);
+
+template <class InputIterator>
+  void iterator insert(const_iterator position, InputIterator first, InputIterator last);
+
+void iterator insert(const_iterator position, initializer_list<T>);
+
      
+
+
      
+23.3.6.4 [vector.modifiers] change return type from void to iterator on following declarations:
+
      
+
+
      void iterator insert(const_iterator position, size_type n, const T& x);
+
+template <class InputIterator>
+  void iterator insert(const_iterator position, InputIterator first, InputIterator last);
+
      
+
+
      
+Add the following (missing) declaration
+
      
+
+
      iterator insert(const_iterator position, initializer_list<T>);
+
      
+
+
+
      
+p1 23.3.7 [vector.bool] Update class definition, change return type from void to iterator:
+
      
+
+
      void iterator insert (const_iterator position, size_type n, const bool& x);
+
+template <class InputIterator>
+  void iterator insert(const_iterator position, InputIterator first, InputIterator last);
+
+  void iterator insert(const_iterator position, initializer_list<bool> il);
+
      
+
+
      
+p5 21.4 [basic.string] Update class definition, change return type from void to iterator:
+
      
+
+
      void iterator insert(const_iterator p, size_type n, charT c);
+
+template<class InputIterator>
+  void iterator insert(const_iterator p, InputIterator first, InputIterator last);
+
+void iterator insert(const_iterator p, initializer_list<charT>);
+
      
+
+
      
+p13 21.4.6.4 [string::insert] change return type from void to iterator:
+
      
+
+
      void iterator insert(const_iterator p, size_type n, charT c);
+
      
+
+
      
+Add paragraph:
+
      
+
+
      
+Returns: an iterator which refers to the copy of the first inserted
+character, or p if n == 0.
+
      
+
+
      
+p15 21.4.6.4 [string::insert] change return type from void to iterator:
+
      
+
+
      template<class InputIterator>
+  void iterator insert(const_iterator p, InputIterator first, InputIterator last);
+
      
+
+
      
+Add paragraph:
+
      
+
+
      
+Returns: an iterator which refers to the copy of the first inserted
+character, or p if first == last.
+
      
+
+
      
+p17 21.4.6.4 [string::insert] change return type from void to iterator:
+
      
+
+
      void iterator insert(const_iterator p, initializer_list<charT> il);
+
      
+
+
      
+Add paragraph:
+
      
+
+
      
+Returns: an iterator which refers to the copy of the first inserted
+character, or p if il is empty.
+
      
+
+
+
+
      Rationale:
      
+
+
      [
+The following was the C++98/03 rationale and does not necessarily apply to the
+proposed resolution in the C++0X time frame:
+]
      
+
+
+
      
+
      The LWG believes this was an intentional design decision and so is
+not a defect. It may be worth revisiting for the next standard.
      
+
      
+
+
+
+
 
      
 
      150. Find_first_of says integer instead of iterator 
      
-
      Section: 25.3.7 [alg.find.first.of] Status: TC1
+
      Section: 25.2.7 [alg.find.first.of] Status: TC1
  Submitter: Matt McClure Opened: 1999-06-30  Last modified: 2008-09-26
      
 
      View all other issues in [alg.find.first.of].
      
 
      View all issues with TC1 status.
      
@@ -6322,7 +6831,7 @@ two places:
      
 
 
 
      Proposed resolution:
      
-
      Change 25.3.7 [alg.find.first.of] paragraph 2 from:
      
+
      Change 25.2.7 [alg.find.first.of] paragraph 2 from:
      
 
 
      
 
      Returns: The first iterator i in the range [first1, last1) such
@@ -6343,6 +6852,7 @@ that for some iterator j in the range [first2, last2) ...
      
 
      151. Can't currently clear() empty container
      
 
      Section: 23.2.3 [sequence.reqmts] Status: TC1
  Submitter: Ed Brey Opened: 1999-06-21  Last modified: 2008-09-26
      
+
      View other active issues in [sequence.reqmts].
      
 
      View all other issues in [sequence.reqmts].
      
 
      View all issues with TC1 status.
      
 
      Discussion:
      
@@ -7036,7 +7546,7 @@ as described in issue 174. Typo: OFF_T vs. POS_T
-
      Section: D.6 [depr.ios.members] Status: TC1
+
      Section: D.7 [depr.ios.members] Status: TC1
  Submitter: Dietmar Kühl Opened: 1999-07-23  Last modified: 2008-09-26
      
 
      View all other issues in [depr.ios.members].
      
 
      View all issues with TC1 status.
      
@@ -7047,7 +7557,7 @@ paragraph 6 the streampos gets the type POS_T
      
 
 
 
      Proposed resolution:
      
-
      Change D.6 [depr.ios.members] paragraph 1 from "typedef
+
      Change D.7 [depr.ios.members] paragraph 1 from "typedef
 OFF_T streampos;" to "typedef POS_T
 streampos;"
      
 
@@ -7056,7 +7566,7 @@ streampos;"
      
 
 
      
 
      175. Ambiguity for basic_streambuf::pubseekpos() and a few other functions.
      
-
      Section: D.6 [depr.ios.members] Status: TC1
+
      Section: D.7 [depr.ios.members] Status: TC1
  Submitter: Dietmar Kühl Opened: 1999-07-23  Last modified: 2008-09-26
      
 
      View all other issues in [depr.ios.members].
      
 
      View all issues with TC1 status.
      
@@ -7075,7 +7585,7 @@ argument is not specified.
      
 
 
 
      Proposed resolution:
      
-
      In D.6 [depr.ios.members] paragraph 8, remove the default arguments for
+
      In D.7 [depr.ios.members] paragraph 8, remove the default arguments for
 basic_streambuf::pubseekpos(),
 basic_ifstream::open(), and
 basic_ofstream::open().
      
@@ -7085,7 +7595,7 @@ argument is not specified.
      
 
 
      
 
      176. exceptions() in ios_base...?
      
-
      Section: D.6 [depr.ios.members] Status: TC1
+
      Section: D.7 [depr.ios.members] Status: TC1
  Submitter: Dietmar Kühl Opened: 1999-07-23  Last modified: 2008-09-26
      
 
      View all other issues in [depr.ios.members].
      
 
      View all issues with TC1 status.
      
@@ -7099,7 +7609,7 @@ in clause 27 [input.output]."
      
 
 
 
      Proposed resolution:
      
-
      In D.6 [depr.ios.members] paragraph 8, move the declaration of the
+
      In D.7 [depr.ios.members] paragraph 8, move the declaration of the
 function exceptions()into class basic_ios.
      
 
 
@@ -7365,7 +7875,7 @@ standard. Also see issue 181. make_pair() unintended behavior
-
      Section: 20.3.3 [pairs] Status: TC1
+
      Section: 20.3.4 [pairs] Status: TC1
  Submitter: Andrew Koenig Opened: 1999-08-03  Last modified: 2008-09-26
      
 
      View other active issues in [pairs].
      
 
      View all other issues in [pairs].
      
@@ -7392,7 +7902,7 @@ declaration of make_pair():
      
 
      
   
      template <class T1, class T2> pair<T1,T2> make_pair(T1, T2);
      
 
      
-
        In 20.3.3 [pairs] paragraph 7 and the line before, change:
      
+
        In 20.3.4 [pairs] paragraph 7 and the line before, change:
      
 
      
 
      template <class T1, class T2>
 pair<T1, T2> make_pair(const T1& x, const T2& y);
      
@@ -7918,12 +8428,12 @@ not required elsewhere.
      
 
 
      
 
      186. bitset::set() second parameter should be bool
      
-
      Section: 20.3.6.2 [bitset.members] Status: CD1
+
      Section: 20.3.7.2 [bitset.members] Status: CD1
  Submitter: Darin Adler Opened: 1999-08-13  Last modified: 2008-09-26
      
 
      View all other issues in [bitset.members].
      
 
      View all issues with CD1 status.
      
 
      Discussion:
      
-
      In section 20.3.6.2 [bitset.members], paragraph 13 defines the
+
      In section 20.3.7.2 [bitset.members], paragraph 13 defines the
 bitset::set operation to take a second parameter of type int. The
 function tests whether this value is non-zero to determine whether to
 set the bit to true or false. The type of this second parameter should
@@ -7935,7 +8445,7 @@ translating 0 to false and any non-zero value to true.
      
 
 
 
      Proposed resolution:
      
-
      In 20.3.6 [template.bitset] Para 1 Replace:
      
+
      In 20.3.7 [template.bitset] Para 1 Replace:
      
 
      
 
      bitset<N>& set(size_t pos, int val = true ); 
      
 
      
@@ -7943,7 +8453,7 @@ translating 0 to false and any non-zero value to true.
      
 
      
   
      bitset<N>& set(size_t pos, bool val = true );
      
 
      
-
      In 20.3.6.2 [bitset.members] Para 12(.5) Replace:
      
+
      In 20.3.7.2 [bitset.members] Para 12(.5) Replace:
      
 
      
   
      bitset<N>& set(size_t pos, int val = 1 );
      
 
      
@@ -7972,7 +8482,7 @@ nonvirtual member of a standard library class.
      
 
 
      
 
      187. iter_swap underspecified
      
-
      Section: 25.4.3 [alg.swap] Status: CD1
+
      Section: 25.3.3 [alg.swap] Status: CD1
  Submitter: Andrew Koenig Opened: 1999-08-14  Last modified: 2008-09-26
      
 
      View all other issues in [alg.swap].
      
 
      View all issues with CD1 status.
      
@@ -8070,7 +8580,7 @@ correct the statement in 27.4.2.2
      
 
 
      
 
      193. Heap operations description incorrect
      
-
      Section: 25.5.6 [alg.heap.operations] Status: TC1
+
      Section: 25.4.6 [alg.heap.operations] Status: TC1
  Submitter: Markus Mauhart Opened: 1999-09-24  Last modified: 2008-09-26
      
 
      View all issues with TC1 status.
      
 
      Duplicate of: 216
      
@@ -8095,7 +8605,7 @@ priority AND time).
      
 
 
 
      Proposed resolution:
      
-
      Change 25.5.6 [alg.heap.operations] property (1) from:
      
+
      Change 25.4.6 [alg.heap.operations] property (1) from:
      
 
      
   
      (1) *a is the largest element
      
 
      
@@ -8169,9 +8679,8 @@ returns traits::eof(), the function calls
 
 
      
 
      198. Validity of pointers and references unspecified after iterator destruction
      
-
      Section: 24.2 [iterator.concepts] Status: CD1
+
      Section: X [iterator.concepts] Status: CD1
  Submitter: Beman Dawes Opened: 1999-11-03  Last modified: 2008-09-30
      
-
      View other active issues in [iterator.concepts].
      
 
      View all other issues in [iterator.concepts].
      
 
      View all issues with CD1 status.
      
 
      Discussion:
      
@@ -8221,14 +8730,14 @@ elements of containers.
      
 
 
      The standard itself assumes that pointers and references obtained
 from an iterator are still valid after iterator destruction or
-change. The definition of reverse_iterator::operator*(), 24.5.1.2.3 [reverse.iter.conv], which returns a reference, defines
+change. The definition of reverse_iterator::operator*(), 24.5.1.3.3 [reverse.iter.conv], which returns a reference, defines
 effects:
      
 
 
      
   
      Iterator tmp = current;
 return *--tmp;
      
 
      
-
      The definition of reverse_iterator::operator->(), 24.5.1.2.4
+
      The definition of reverse_iterator::operator->(), 24.5.1.3.4
 [reverse.iter.op.star], which returns a pointer, defines effects:
      
 
      
   
      return &(operator*());
      
@@ -8242,13 +8751,13 @@ implementation.
      
 
 
 
      Proposed resolution:
      
-
      Add a new paragraph to 24.2 [iterator.concepts]:
      
+
      Add a new paragraph to X [iterator.concepts]:
      
 
      
 Destruction of an iterator may invalidate pointers and references
 previously obtained from that iterator.
 
      
 
-
      Replace paragraph 1 of 24.5.1.2.3 [reverse.iter.conv] with:
      
+
      Replace paragraph 1 of 24.5.1.3.3 [reverse.iter.conv] with:
      
 
 
      
 
      Effects:
      
@@ -8261,7 +8770,7 @@ previously obtained from that iterator.
 [Note: This operation must use an auxiliary member variable,
 rather than a temporary variable, to avoid returning a reference that
 persists beyond the lifetime of its associated iterator.  (See
-24.2 [iterator.concepts].)  The name of this member variable is shown for
+X [iterator.concepts].)  The name of this member variable is shown for
 exposition only.  --end note]
 
      
 
      
@@ -8311,9 +8820,8 @@ predefined iterators are as strong as users expect.
      
 
 
      
 
      199. What does allocate(0) return?
      
-
      Section: X [allocator.requirements] Status: TC1
+
      Section: 20.2.2 [allocator.requirements] Status: TC1
  Submitter: Matt Austern Opened: 1999-11-19  Last modified: 2008-09-26
      
-
      View other active issues in [allocator.requirements].
      
 
      View all other issues in [allocator.requirements].
      
 
      View all issues with TC1 status.
      
 
      Discussion:
      
@@ -8347,7 +8855,7 @@ would be over-specification to mandate the return value.
 
 
      
 
      200. Forward iterator requirements don't allow constant iterators
      
-
      Section: 24.2.4 [forward.iterators] Status: CD1
+
      Section: 24.2.3 [forward.iterators] Status: CD1
  Submitter: Matt Austern Opened: 1999-11-19  Last modified: 2008-09-26
      
 
      View all other issues in [forward.iterators].
      
 
      View all issues with CD1 status.
      
@@ -8469,7 +8977,7 @@ which do not.
 
 
      
 
      202. unique() effects unclear when predicate not an equivalence relation
      
-
      Section: 25.4.9 [alg.unique] Status: CD1
+
      Section: 25.3.9 [alg.unique] Status: CD1
  Submitter: Andrew Koenig Opened: 2000-01-13  Last modified: 2008-09-26
      
 
      View all other issues in [alg.unique].
      
 
      View all issues with CD1 status.
      
@@ -8542,7 +9050,7 @@ In fact, the SGI implementation of unique() does neither: It yields 1,
 
 
 
      Proposed resolution:
      
-
      Change 25.4.9 [alg.unique] paragraph 1 to:
      
+
      Change 25.3.9 [alg.unique] paragraph 1 to:
      
 
      
 For a nonempty range, eliminates all but the first element from every
 consecutive group of equivalent elements referred to by the iterator
@@ -8577,7 +9085,7 @@ require another round of review.]
      
 
 
      Rationale:
      
 
      The LWG also considered an alternative resolution: change 
-25.4.9 [alg.unique] paragraph 1 to:
      
+25.3.9 [alg.unique] paragraph 1 to:
      
 
 
      
 For a nonempty range, eliminates all but the first element from every
@@ -8903,9 +9411,8 @@ his customers.
 
 
      
 
      208. Unnecessary restriction on past-the-end iterators
      
-
      Section: 24.2 [iterator.concepts] Status: TC1
+
      Section: X [iterator.concepts] Status: TC1
  Submitter: Stephen Cleary Opened: 2000-02-02  Last modified: 2008-09-30
      
-
      View other active issues in [iterator.concepts].
      
 
      View all other issues in [iterator.concepts].
      
 
      View all issues with TC1 status.
      
 
      Discussion:
      
@@ -8922,7 +9429,7 @@ iterators obtained from different (generic) containers being not equal.
      
 
 
 
      Proposed resolution:
      
-
      Change 24.2 [iterator.concepts] paragraph 5, the last sentence, from:
      
+
      Change X [iterator.concepts] paragraph 5, the last sentence, from:
      
 
      
 
      Dereferenceable and past-the-end values are always non-singular.
      
 
      
@@ -9055,7 +9562,7 @@ is.setstate(ios::failbit) which may throw ios_base::failure
 
 
      
 
      212. Empty range behavior unclear for several algorithms
      
-
      Section: 25.5.7 [alg.min.max] Status: TC1
+
      Section: 25.4.7 [alg.min.max] Status: TC1
  Submitter: Nico Josuttis Opened: 2000-02-26  Last modified: 2008-09-26
      
 
      View all other issues in [alg.min.max].
      
 
      View all issues with TC1 status.
      
@@ -9067,7 +9574,7 @@ next_permutation(), and prev_permutation().
      
 
 
 
      Proposed resolution:
      
-
      In 25.5.7 [alg.min.max] - Minimum and maximum, paragraphs 7 and
+
      In 25.4.7 [alg.min.max] - Minimum and maximum, paragraphs 7 and
 9, append: Returns last if first==last.
      
 
 
@@ -9331,7 +9838,7 @@ footnote.
      
 
 
      
 
      223. reverse algorithm should use iter_swap rather than swap
      
-
      Section: 25.4.10 [alg.reverse] Status: TC1
+
      Section: 25.3.10 [alg.reverse] Status: TC1
  Submitter: Dave Abrahams Opened: 2000-03-21  Last modified: 2008-09-26
      
 
      View all issues with TC1 status.
      
 
      Discussion:
      
@@ -9339,7 +9846,7 @@ footnote.
      
 
 
 
      Proposed resolution:
      
-
      In 25.4.10 [alg.reverse], replace:
      
+
      In 25.3.10 [alg.reverse], replace:
      
   
      
   Effects: For each non-negative integer i <= (last - first)/2, 
   applies swap to all pairs of iterators first + i, (last - i) - 1.
@@ -9357,6 +9864,7 @@ footnote.
      
 
      224. clear() complexity for associative containers refers to undefined N
      
 
      Section: 23.2.4 [associative.reqmts] Status: TC1
  Submitter: Ed Brey Opened: 2000-03-23  Last modified: 2008-09-26
      
+
      View other active issues in [associative.reqmts].
      
 
      View all other issues in [associative.reqmts].
      
 
      View all issues with TC1 status.
      
 
      Discussion:
      
@@ -9705,7 +10213,7 @@ resolution is the one proposed by Howard.]
      
 
 
      
 
      227. std::swap() should require CopyConstructible or DefaultConstructible arguments
      
-
      Section: 25.4.3 [alg.swap] Status: TC1
+
      Section: 25.3.3 [alg.swap] Status: TC1
  Submitter: Dave Abrahams Opened: 2000-04-09  Last modified: 2008-09-26
      
 
      View all other issues in [alg.swap].
      
 
      View all issues with TC1 status.
      
@@ -10002,7 +10510,7 @@ Assignable"
 CopyConstructible and Assignable"
      
 
      
 
-
      In 24.2.3 [output.iterators] paragraph 1, change:
+
      In 24.2.2 [output.iterators] paragraph 1, change:
 
      
 
      
 
       A class or a built-in type X satisfies the requirements of an
@@ -10021,7 +10529,7 @@ Table 73:
 
      
 
 
      [Post-Tokyo: Beman Dawes submitted this issue at the request of
-the LWG.  He asks that the 25.4.5 [alg.replace] and 25.4.6 [alg.fill] changes be studied carefully, as it is not clear that
+the LWG.  He asks that the 25.3.5 [alg.replace] and 25.3.6 [alg.fill] changes be studied carefully, as it is not clear that
 CopyConstructible is really a requirement and may be
 overspecification.]
      
 
@@ -10184,6 +10692,7 @@ rationale.]
      
 
      233. Insertion hints in associative containers
      
 
      Section: 23.2.4 [associative.reqmts] Status: CD1
  Submitter: Andrew Koenig Opened: 2000-04-30  Last modified: 2008-09-26
      
+
      View other active issues in [associative.reqmts].
      
 
      View all other issues in [associative.reqmts].
      
 
      View all issues with CD1 status.
      
 
      Duplicate of: 192, 246
      
@@ -10333,7 +10842,7 @@ logarithmic in general, but amortized constant if t is inserted right <
 
 
      
 
      234. Typos in allocator definition
      
-
      Section: 20.8.4.1 [allocator.members] Status: CD1
+
      Section: 20.8.8.1 [allocator.members] Status: CD1
  Submitter: Dietmar Kühl Opened: 2000-04-24  Last modified: 2008-09-26
      
 
      View all other issues in [allocator.members].
      
 
      View all issues with CD1 status.
      
@@ -10361,7 +10870,7 @@ should do.
      
 
 
 
      Proposed resolution:
      
-  
      In section 24.5.1.2.1 [reverse.iter.cons] add the following
+  
      In section 24.5.1.3.1 [reverse.iter.cons] add the following
   paragraph:
      
       
      
       
      reverse_iterator()
      
@@ -10405,6 +10914,7 @@ would have to be last - first.
      
 
      238. Contradictory results of stringbuf initialization.
      
 
      Section: 27.8.1.1 [stringbuf.cons] Status: CD1
  Submitter: Dietmar Kühl Opened: 2000-05-11  Last modified: 2008-09-26
      
+
      View all other issues in [stringbuf.cons].
      
 
      View all issues with CD1 status.
      
 
      Discussion:
      
 
      In 27.7.1.1 paragraph 4 the results of calling the constructor of
@@ -10440,7 +10950,7 @@ in the standard.
      
 
 
      
 
      239. Complexity of unique() and/or unique_copy incorrect
      
-
      Section: 25.4.9 [alg.unique] Status: CD1
+
      Section: 25.3.9 [alg.unique] Status: CD1
  Submitter: Angelika Langer Opened: 2000-05-15  Last modified: 2008-09-26
      
 
      View all other issues in [alg.unique].
      
 
      View all issues with CD1 status.
      
@@ -10473,7 +10983,7 @@ twice.
      
 
 
 
      Proposed resolution:
      
-
      Change both complexity sections in 25.4.9 [alg.unique] to:
      
+
      Change both complexity sections in 25.3.9 [alg.unique] to:
      
 
 
      Complexity: For nonempty ranges, exactly last - first - 1
 applications of the corresponding predicate.
      
@@ -10485,7 +10995,7 @@ applications of the corresponding predicate.
      
 
 
      
 
      240. Complexity of adjacent_find() is meaningless
      
-
      Section: 25.3.8 [alg.adjacent.find] Status: CD1
+
      Section: 25.2.8 [alg.adjacent.find] Status: CD1
  Submitter: Angelika Langer Opened: 2000-05-15  Last modified: 2008-09-26
      
 
      View all other issues in [alg.adjacent.find].
      
 
      View all issues with CD1 status.
      
@@ -10526,7 +11036,7 @@ an "as-if" specification.
      
 
 
 
      Proposed resolution:
      
-
      Change the complexity section in 25.3.8 [alg.adjacent.find] to:
      
+
      Change the complexity section in 25.2.8 [alg.adjacent.find] to:
      
 
      
 For a nonempty range, exactly min((i - first) + 1,
 (last - first) - 1) applications of the
@@ -10545,7 +11055,7 @@ bound.  The LWG preferred an exact count.]
      
 
 
      
 
      241. Does unique_copy() require CopyConstructible and Assignable?
      
-
      Section: 25.4.9 [alg.unique] Status: CD1
+
      Section: 25.3.9 [alg.unique] Status: CD1
  Submitter: Angelika Langer Opened: 2000-05-15  Last modified: 2008-09-26
      
 
      View all other issues in [alg.unique].
      
 
      View all issues with CD1 status.
      
@@ -10614,7 +11124,7 @@ minor as not to require re-review.
 
 
      
 
      242. Side effects of function objects
      
-
      Section: 25.4.4 [alg.transform], 26.5 [rand] Status: CD1
+
      Section: 25.3.4 [alg.transform], 26.5 [rand] Status: CD1
  Submitter: Angelika Langer Opened: 2000-05-15  Last modified: 2008-09-26
      
 
      View all other issues in [alg.transform].
      
 
      View all issues with CD1 status.
      
@@ -10972,6 +11482,7 @@ input facets.
      
 
      250. splicing invalidates iterators
      
 
      Section: 23.3.4.4 [list.ops] Status: CD1
  Submitter: Brian Parker  Opened: 2000-07-14  Last modified: 2008-09-26
      
+
      View other active issues in [list.ops].
      
 
      View all other issues in [list.ops].
      
 
      View all issues with CD1 status.
      
 
      Discussion:
      
@@ -11749,9 +12260,8 @@ copyfmt_event.
 
 
      
 
      258. Missing allocator requirement
      
-
      Section: X [allocator.requirements] Status: CD1
+
      Section: 20.2.2 [allocator.requirements] Status: CD1
  Submitter: Matt Austern Opened: 2000-08-22  Last modified: 2008-09-26
      
-
      View other active issues in [allocator.requirements].
      
 
      View all other issues in [allocator.requirements].
      
 
      View all issues with CD1 status.
      
 
      Discussion:
      
@@ -12070,6 +12580,7 @@ Change the following sentence in 21.3 paragraph 5 from
 
      264. Associative container insert(i, j) complexity requirements are not feasible.
      
 
      Section: 23.2.4 [associative.reqmts] Status: CD1
  Submitter: John Potter Opened: 2000-09-07  Last modified: 2008-09-26
      
+
      View other active issues in [associative.reqmts].
      
 
      View all other issues in [associative.reqmts].
      
 
      View all issues with CD1 status.
      
 
      Duplicate of: 102
      
@@ -12122,7 +12633,7 @@ linear in some special cases.
 
 
      
 
      265. std::pair::pair() effects overly restrictive
      
-
      Section: 20.3.3 [pairs] Status: CD1
+
      Section: 20.3.4 [pairs] Status: CD1
  Submitter: Martin Sebor Opened: 2000-09-11  Last modified: 2008-09-26
      
 
      View other active issues in [pairs].
      
 
      View all other issues in [pairs].
      
@@ -12188,8 +12699,8 @@ clause is missing).
 
      
 Remove the destructor from the class synopses of 
 bad_alloc (18.6.2.1 [bad.alloc]),
-bad_cast (18.7.3 [bad.cast]),
-bad_typeid (18.7.4 [bad.typeid]),
+bad_cast (18.7.2 [bad.cast]),
+bad_typeid (18.7.3 [bad.typeid]),
 and bad_exception (18.8.2.1 [bad.exception]).
 
      
 
@@ -12239,7 +12750,7 @@ are missing.
      
 
 
      
 
      270. Binary search requirements overly strict
      
-
      Section: 25.5.3 [alg.binary.search] Status: CD1
+
      Section: 25.4.3 [alg.binary.search] Status: CD1
  Submitter: Matt Austern Opened: 2000-10-18  Last modified: 2008-09-26
      
 
      View all other issues in [alg.binary.search].
      
 
      View all issues with CD1 status.
      
@@ -12584,9 +13095,8 @@ members, i.e., ios_base.
      
 
 
      
 
      274. a missing/impossible allocator requirement
      
-
      Section: X [allocator.requirements] Status: CD1
+
      Section: 20.2.2 [allocator.requirements] Status: CD1
  Submitter: Martin Sebor Opened: 2000-11-02  Last modified: 2008-09-26
      
-
      View other active issues in [allocator.requirements].
      
 
      View all other issues in [allocator.requirements].
      
 
      View all issues with CD1 status.
      
 
      Discussion:
      
@@ -12873,6 +13383,7 @@ implement vector::push_back in terms of
 
      278. What does iterator validity mean?
      
 
      Section: 23.3.4.4 [list.ops] Status: CD1
  Submitter: P.J. Plauger Opened: 2000-11-27  Last modified: 2008-09-30
      
+
      View other active issues in [list.ops].
      
 
      View all other issues in [list.ops].
      
 
      View all issues with CD1 status.
      
 
      Discussion:
      
@@ -12905,7 +13416,7 @@ introduce separate terms for the two kinds of "validity."
 
 
 
      Proposed resolution:
      
-
      Add the following text to the end of section 24.2 [iterator.concepts],
+
      Add the following text to the end of section X [iterator.concepts],
 after paragraph 5:
      
 
      
 An invalid iterator is an iterator that may be
@@ -12996,7 +13507,7 @@ add/change the following declarations:
      
 
    
 
    
 Also make the addition/changes for these signatures in 
-24.5.1.2 [reverse.iter.ops].
+24.5.1.3 [reverse.iter.ops].
 
    
 
 
    [
@@ -13021,7 +13532,7 @@ this solution is safe and correct.
 
 
    
 
    281. std::min() and max() requirements overly restrictive
    
-
    Section: 25.5.7 [alg.min.max] Status: CD1
+
    Section: 25.4.7 [alg.min.max] Status: CD1
  Submitter: Martin Sebor Opened: 2000-12-02  Last modified: 2008-09-26
    
 
    View all other issues in [alg.min.max].
    
 
    View all issues with CD1 status.
    
@@ -13029,7 +13540,7 @@ this solution is safe and correct.
 
    Discussion:
    
 
    The requirements in 25.3.7, p1 and 4 call for T to satisfy the
 requirements of LessThanComparable ( [lessthancomparable])
-and CopyConstructible (X [utility.arg.requirements]).
+and CopyConstructible (20.2.1 [utility.arg.requirements]).
 Since the functions take and return their arguments and result by
 const reference, I believe the CopyConstructible requirement
 is unnecessary.
@@ -13111,7 +13622,7 @@ Howard, Bill, Pete, Benjamin, Nathan, Dietmar, Boris, and Martin.]
    
 
 
    
 
    283. std::replace() requirement incorrect/insufficient
    
-
    Section: 25.4.5 [alg.replace] Status: CD1
+
    Section: 25.3.5 [alg.replace] Status: CD1
  Submitter: Martin Sebor Opened: 2000-12-15  Last modified: 2008-09-26
    
 
    View all other issues in [alg.replace].
    
 
    View all issues with CD1 status.
    
@@ -13273,11 +13784,11 @@ imposing a greater restriction that what the standard currently says
 
 
    
 
    284. unportable example in 20.3.7, p6
    
-
    Section: 20.7.8 [comparisons] Status: CD1
+
    Section: 20.7.7 [comparisons] Status: CD1
  Submitter: Martin Sebor Opened: 2000-12-26  Last modified: 2008-09-26
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
-
    The example in 20.7.8 [comparisons], p6 shows how to use the C
+
    The example in 20.7.7 [comparisons], p6 shows how to use the C
 library function strcmp() with the function pointer adapter
 ptr_fun(). But since it's unspecified whether the C library
 functions have extern "C" or extern
@@ -13289,7 +13800,7 @@ well-formed is unspecified.
 
 
 
    Proposed resolution:
    
-
    Change 20.7.8 [comparisons] paragraph 6 from:
    
+
    Change 20.7.7 [comparisons] paragraph 6 from:
    
 
    
   
    [Example:
    
   
        replace_if(v.begin(), v.end(), not1(bind2nd(ptr_fun(strcmp), "C")), "C++");
@@ -13357,7 +13868,7 @@ paragraphs mentioned above.
 
 
    
 
    286. <cstdlib> requirements missing size_t typedef
    
-
    Section: 25.6 [alg.c.library] Status: CD1
+
    Section: 25.5 [alg.c.library] Status: CD1
  Submitter: Judy Ward Opened: 2000-12-30  Last modified: 2008-09-26
    
 
    View all other issues in [alg.c.library].
    
 
    View all issues with CD1 status.
    
@@ -13416,7 +13927,7 @@ and Table 95 (section C.2) "Standard Macros" to include EILSEQ.
 
 
    
 
    291. Underspecification of set algorithms
    
-
    Section: 25.5.5 [alg.set.operations] Status: CD1
+
    Section: 25.4.5 [alg.set.operations] Status: CD1
  Submitter: Matt Austern Opened: 2001-01-03  Last modified: 2008-09-26
    
 
    View all other issues in [alg.set.operations].
    
 
    View all issues with CD1 status.
    
@@ -13473,7 +13984,7 @@ same way.
 
 
    Proposed resolution:
    
 
-
    Add the following to the end of 25.5.5.2 [set.union] paragraph 5:
    
+
    Add the following to the end of 25.4.5.2 [set.union] paragraph 5:
    
 
    
 If [first1, last1) contains m elements that are equivalent to
 each other and [first2, last2) contains n elements that are
@@ -13483,7 +13994,7 @@ from [first1, last1), and the last max(n-m, 0) of them from
 [first2, last2), in that order.
 
    
 
-
    Add the following to the end of 25.5.5.3 [set.intersection] paragraph 5:
    
+
    Add the following to the end of 25.4.5.3 [set.intersection] paragraph 5:
    
 
    
 If [first1, last1) contains m elements that are equivalent to each
 other and [first2, last2) contains n elements that are
@@ -13491,7 +14002,7 @@ equivalent to them, the first min(m, n) of those
 elements from [first1, last1) are copied to the output range.
 
    
 
-
    Add a new paragraph, Notes, after 25.5.5.4 [set.difference]
+
    Add a new paragraph, Notes, after 25.4.5.4 [set.difference]
 paragraph 4:
    
 
    
 If [first1, last1) contains m elements that are equivalent to each
@@ -13500,7 +14011,7 @@ equivalent to them, the last max(m-n, 0) elements from
 [first1, last1) are copied to the output range.
 
    
 
-
    Add a new paragraph, Notes, after 25.5.5.5 [set.symmetric.difference]
+
    Add a new paragraph, Notes, after 25.4.5.5 [set.symmetric.difference]
 paragraph 4:
    
 
    
 If [first1, last1) contains m elements that are equivalent to
@@ -13669,7 +14180,7 @@ putting in <cstdlib>.  That's issue 297. const_mem_fun_t<>::argument_type should be const T*
-
    Section: 20.7.9 [logical.operations] Status: CD1
+
    Section: 20.7.8 [logical.operations] Status: CD1
  Submitter: Martin Sebor Opened: 2001-01-06  Last modified: 2008-09-26
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
@@ -13804,6 +14315,7 @@ or operator delete(ptr, std::nothrow) respectively.
 
    300. list::merge() specification incomplete
    
 
    Section: 23.3.4.4 [list.ops] Status: CD1
  Submitter: John Pedretti Opened: 2001-01-23  Last modified: 2008-09-26
    
+
    View other active issues in [list.ops].
    
 
    View all other issues in [list.ops].
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
@@ -13901,7 +14413,7 @@ a mistake.
 
 
    
 
    303. Bitset input operator underspecified
    
-
    Section: 20.3.6.3 [bitset.operators] Status: CD1
+
    Section: 20.3.7.3 [bitset.operators] Status: CD1
  Submitter: Matt Austern Opened: 2001-02-05  Last modified: 2008-09-26
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
@@ -14221,7 +14733,7 @@ container's reference type.
    
 
 
    
 I propose 3.  This does not preclude option 2 if we choose to do it
-later (see issue 96); the issues are independent.  Option
+later (see issue 96); the issues are independent.  Option
 3 offers a small step towards support for proxied containers.  This
 small step fixes a current contradiction, is easy for vendors to
 implement, is already implemented in at least one popular lib, and
@@ -14657,6 +15169,7 @@ as <memory>.
    
 
    315. Bad "range" in list::unique complexity
    
 
    Section: 23.3.4.4 [list.ops] Status: CD1
  Submitter: Andy Sawyer Opened: 2001-05-01  Last modified: 2008-09-26
    
+
    View other active issues in [list.ops].
    
 
    View all other issues in [list.ops].
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
@@ -14684,6 +15197,7 @@ Change the "range" from (last - first) to [first, last).
 
    316. Vague text in Table 69
    
 
    Section: 23.2.4 [associative.reqmts] Status: CD1
  Submitter: Martin Sebor Opened: 2001-05-04  Last modified: 2008-09-26
    
+
    View other active issues in [associative.reqmts].
    
 
    View all other issues in [associative.reqmts].
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
@@ -15031,7 +15545,7 @@ requires that iterator_traits<const int*>::value_type is int.
 
 
    
 
    324. Do output iterators have value types?
    
-
    Section: 24.2.3 [output.iterators] Status: CD1
+
    Section: 24.2.2 [output.iterators] Status: CD1
  Submitter: Dave Abrahams Opened: 2001-06-07  Last modified: 2008-09-26
    
 
    View all other issues in [output.iterators].
    
 
    View all issues with CD1 status.
    
@@ -15389,7 +15903,7 @@ reallocation guarantees was inadvertant.
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
 
    
-With the change in 17.6.4.10 [res.on.exception.handling] to state
+With the change in 17.6.4.11 [res.on.exception.handling] to state
    "An implementation may strengthen the exception-specification for a 
     non-virtual function by removing listed exceptions."
 (issue 119)
@@ -15692,7 +16206,7 @@ library (though a deprecated one).
    
 
  • 17.6.1.2 [headers] Headers/4
    • 
 
  • 17.6.3.6 [replacement.functions] Replacement functions/1
    • 
 
  • 17.6.4.4 [global.functions] Global or non-member functions/2
    • 
-
  • 17.6.4.8 [protection.within.classes] Protection within classes/1
    • 
+
  • 17.6.4.9 [protection.within.classes] Protection within classes/1
    • 
 
 
 
@@ -15703,7 +16217,7 @@ library (though a deprecated one).
    
 
 
    
 
    337. replace_copy_if's template parameter should be InputIterator
    
-
    Section: 25.4.5 [alg.replace] Status: CD1
+
    Section: 25.3.5 [alg.replace] Status: CD1
  Submitter: Detlef Vollmann Opened: 2001-09-07  Last modified: 2008-09-26
    
 
    View all other issues in [alg.replace].
    
 
    View all issues with CD1 status.
    
@@ -15711,7 +16225,7 @@ library (though a deprecated one).
    
 
    From c++std-edit-876:
    
 
 
    
-In section 25.4.5 [alg.replace] before p4: The name of the first
+In section 25.3.5 [alg.replace] before p4: The name of the first
 parameter of template replace_copy_if should be "InputIterator"
 instead of "Iterator".  According to 17.5.2.1 [type.descriptions] p1 the
 parameter name conveys real normative meaning.
@@ -15820,7 +16334,7 @@ clause 27, making the reference in 22.2.1 somewhat dubious.
     
    
     Several types defined in clause 27 are bitmask types. Each bitmask type
     can be implemented as an enumerated type that overloads certain operators,
-    as an integer type, or as a bitset (20.3.6 [template.bitset]).
+    as an integer type, or as a bitset (20.3.7 [template.bitset]).
     
    
 
    to read
    
     
    
@@ -16044,9 +16558,8 @@ declares struct tm as an incomplete type. However, table 48 in 21.6
 
 
    
 
    346. Some iterator member functions should be const
    
-
    Section: 24.2 [iterator.concepts] Status: CD1
+
    Section: X [iterator.concepts] Status: CD1
  Submitter: Jeremy Siek Opened: 2001-10-20  Last modified: 2008-09-30
    
-
    View other active issues in [iterator.concepts].
    
 
    View all other issues in [iterator.concepts].
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
@@ -16063,7 +16576,7 @@ make this more explicit and also fix a couple problems.
    
 
 
 
    Proposed resolution:
    
-
    In 24.2 [iterator.concepts] Change the first section of p9 from
+
    In X [iterator.concepts] Change the first section of p9 from
 "In the following sections, a and b denote values of X..." to
 "In the following sections, a and b denote values of type const X...".
    
 
@@ -16231,6 +16744,7 @@ In 24.6.2 [ostream.iterator], replace const char* delim with
 
    352. missing fpos requirements
    
 
    Section: 21.2.2 [char.traits.typedefs] Status: CD1
  Submitter: Martin Sebor Opened: 2001-12-02  Last modified: 2008-09-26
    
+
    View all other issues in [char.traits.typedefs].
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
 
    
@@ -16287,6 +16801,7 @@ be considered NAD.
    
 
    354. Associative container lower/upper bound requirements
    
 
    Section: 23.2.4 [associative.reqmts] Status: CD1
  Submitter: Hans Aberg Opened: 2001-12-17  Last modified: 2008-09-26
    
+
    View other active issues in [associative.reqmts].
    
 
    View all other issues in [associative.reqmts].
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
@@ -16353,6 +16868,7 @@ key greater than k, or a.end() if such an element is not found.
 
    355. Operational semantics for a.back()
    
 
    Section: 23.2.3 [sequence.reqmts] Status: CD1
  Submitter: Yaroslav Mironov Opened: 2002-01-23  Last modified: 2008-09-26
    
+
    View other active issues in [sequence.reqmts].
    
 
    View all other issues in [sequence.reqmts].
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
@@ -16640,13 +17156,13 @@ prevents locale from being implemented efficiently.
 
 
    
 
    362. bind1st/bind2nd type safety
    
-
    Section: D.8 [depr.lib.binders] Status: CD1
+
    Section: D.9 [depr.lib.binders] Status: CD1
  Submitter: Andrew Demkin Opened: 2002-04-26  Last modified: 2008-09-26
    
 
    View all other issues in [depr.lib.binders].
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
 
    
-The definition of bind1st() (D.8 [depr.lib.binders]) can result in
+The definition of bind1st() (D.9 [depr.lib.binders]) can result in
 the construction of an unsafe binding between incompatible pointer
 types. For example, given a function whose first parameter type is
 'pointer to T', it's possible without error to bind an argument of
@@ -16673,19 +17189,19 @@ map its argument to the expected argument type of the bound function
 
      typename Operation::first_argument_type(x)
 
    
 
-
    A functional-style conversion (D.8 [depr.lib.binders]) is defined to
+
    A functional-style conversion (D.9 [depr.lib.binders]) is defined to
 be
-semantically equivalent to an explicit cast expression (D.8
+semantically equivalent to an explicit cast expression (D.9
 [depr.lib.binders]), which may (according to 5.4, paragraph 5) be
 interpreted
 as a reinterpret_cast, thus masking the error.
 
    
 
-
    The problem and proposed change also apply to D.8 [depr.lib.binders].
    
+
    The problem and proposed change also apply to D.9 [depr.lib.binders].
    
 
 
 
    Proposed resolution:
    
-
    Add this sentence to the end of D.8 [depr.lib.binders]/1:
+
    Add this sentence to the end of D.9 [depr.lib.binders]/1:
   "Binders bind1st and bind2nd are deprecated in
   favor of std::tr1::bind."
    
 
@@ -17347,7 +17863,7 @@ values, or that choose to detect any other kind of error, may return
 
 
    
 
    383. Bidirectional iterator assertion typo
    
-
    Section: 24.2.5 [bidirectional.iterators] Status: CD1
+
    Section: 24.2.4 [bidirectional.iterators] Status: CD1
  Submitter: ysapir (submitted via comp.std.c++) Opened: 2002-10-17  Last modified: 2008-09-26
    
 
    View all other issues in [bidirectional.iterators].
    
 
    View all issues with CD1 status.
    
@@ -17416,13 +17932,13 @@ Change the guarantee to "postcondition: r is dereferenceable."
 
 
    
 
    384. equal_range has unimplementable runtime complexity
    
-
    Section: 25.5.3.3 [equal.range] Status: CD1
+
    Section: 25.4.3.3 [equal.range] Status: CD1
  Submitter: Hans Bos Opened: 2002-10-18  Last modified: 2008-09-26
    
 
    View all other issues in [equal.range].
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
 
    
-Section 25.5.3.3 [equal.range]
+Section 25.4.3.3 [equal.range]
 states that at most 2 * log(last - first) + 1
 comparisons are allowed for equal_range.
 
    
@@ -17461,13 +17977,13 @@ but 2log(distance) + 4 for the worst case).
 
 
 
    Proposed resolution:
    
-
    In 25.5.3.1 [lower.bound]/4, change log(last - first) + 1
+
    In 25.4.3.1 [lower.bound]/4, change log(last - first) + 1
 to log2(last - first) + O(1).
    
 
-
    In 25.5.3.2 [upper.bound]/4, change log(last - first) + 1
+
    In 25.4.3.2 [upper.bound]/4, change log(last - first) + 1
 to log2(last - first) + O(1).
    
 
-
    In 25.5.3.3 [equal.range]/4, change 2*log(last - first) + 1
+
    In 25.4.3.3 [equal.range]/4, change 2*log(last - first) + 1
 to 2*log2(last - first) + O(1).
    
 
 
    [Matt provided wording]
    
@@ -17488,11 +18004,11 @@ to 2*log2(last - first) + O(1).
    
 
 
    
 
    386. Reverse iterator's operator[] has impossible return type
    
-
    Section: 24.5.1.2.11 [reverse.iter.op-=] Status: CD1
+
    Section: 24.5.1.3.11 [reverse.iter.op-=] Status: CD1
  Submitter: Matt Austern Opened: 2002-10-23  Last modified: 2009-05-01
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
-
    In 24.5.1.2.11 [reverse.iter.op-=], reverse_iterator<>::operator[] 
+
    In 24.5.1.3.11 [reverse.iter.op-=], reverse_iterator<>::operator[] 
 is specified as having a return type of reverse_iterator::reference,
 which is the same as iterator_traits<Iterator>::reference.
 (Where Iterator is the underlying iterator type.)
    
@@ -17518,7 +18034,7 @@ which is the same as iterator_traits<Iterator>::reference.
 
 
    Proposed resolution:
    
 
-
    In  [reverse.iter.requirements] change:
    
+
    In 24.5.1.2 [reverse.iter.requirements] change:
    
 
 
    
 
    reference operator[](difference_type n) const;
@@ -17528,7 +18044,7 @@ which is the same as iterator_traits<Iterator>::reference.
 
    to:
    
 
 
    
-
    unspecified operator[](difference_type n) const; // see 24.2.6 [random.access.iterators]
+
    unspecified operator[](difference_type n) const; // see 24.2.5 [random.access.iterators]
 
    
 
    
 
@@ -17818,7 +18334,7 @@ function."
 
    
 
 
    
-In 25.4.12 [alg.random.shuffle], there is no specification as to
+In 25.3.12 [alg.random.shuffle], there is no specification as to
 how the two parameter version of the function generates its random
 value.  I believe that all current implementations in fact call rand()
 (in contradiction with the requirement avove); if an implementation does
@@ -17859,7 +18375,7 @@ implementation is permitted to use rand.]
 
 
    
 
    396. what are characters zero and one
    
-
    Section: 20.3.6.1 [bitset.cons] Status: CD1
+
    Section: 20.3.7.1 [bitset.cons] Status: CD1
  Submitter: Martin Sebor Opened: 2003-01-05  Last modified: 2008-09-26
    
 
    View all other issues in [bitset.cons].
    
 
    View all issues with CD1 status.
    
@@ -17918,7 +18434,7 @@ We request that Howard submit a separate issue regarding the three to_string ove
 
 
    Proposed resolution:
    
 
    Change the constructor's function declaration immediately before 
-20.3.6.1 [bitset.cons] p3 to:
    
+20.3.7.1 [bitset.cons] p3 to:
    
 
        template <class charT, class traits, class Allocator>
     explicit
     bitset(const basic_string<charT, traits, Allocator>& str,
@@ -17927,7 +18443,7 @@ We request that Howard submit a separate issue regarding the three to_string ove
              basic_string<charT, traits, Allocator>::npos,
            charT zero = charT('0'), charT one = charT('1'))
 
    
-
    Change the first two sentences of 20.3.6.1 [bitset.cons] p6 to: "An
+
    Change the first two sentences of 20.3.7.1 [bitset.cons] p6 to: "An
 element of the constructed string has value 0 if the corresponding
 character in str, beginning at position pos,
 is zero. Otherwise, the element has the value 1.
    
@@ -17940,15 +18456,15 @@ is zero. Otherwise, the element has the value 1.
    
 
    
 
 
    Change the declaration of the to_string member function
-  immediately before 20.3.6.2 [bitset.members] p33 to:
    
+  immediately before 20.3.7.2 [bitset.members] p33 to:
    
 
        template <class charT, class traits, class Allocator>
     basic_string<charT, traits, Allocator> 
     to_string(charT zero = charT('0'), charT one = charT('1')) const;
 
    
-
    Change the last sentence of 20.3.6.2 [bitset.members] p33 to: "Bit
+
    Change the last sentence of 20.3.7.2 [bitset.members] p33 to: "Bit
   value 0 becomes the character zero, bit value 1 becomes the
   character one.
    
-
    Change 20.3.6.3 [bitset.operators] p8 to:
    
+
    Change 20.3.7.3 [bitset.operators] p8 to:
    
 
    Returns:
     
 
      os << x.template to_string<charT,traits,allocator<charT> >(
       use_facet<ctype<charT> >(os.getloc()).widen('0'),
@@ -17993,13 +18509,13 @@ The proposed wording neglects the 3 newer to_string overloads.
 
 
    
 
    400. redundant type cast in lib.allocator.members
    
-
    Section: 20.8.4.1 [allocator.members] Status: CD1
+
    Section: 20.8.8.1 [allocator.members] Status: CD1
  Submitter: Markus Mauhart Opened: 2003-02-27  Last modified: 2008-09-26
    
 
    View all other issues in [allocator.members].
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
 
    
-20.8.4.1 [allocator.members] allocator members, contains
+20.8.8.1 [allocator.members] allocator members, contains
 the following 3 lines:
 
    
 
@@ -18027,9 +18543,8 @@ Replace "((T*) p)" with "p".
 
 
    
 
    401.  incorrect type casts in table 32 in lib.allocator.requirements
    
-
    Section: X [allocator.requirements] Status: CD1
+
    Section: 20.2.2 [allocator.requirements] Status: CD1
  Submitter: Markus Mauhart Opened: 2003-02-27  Last modified: 2008-09-26
    
-
    View other active issues in [allocator.requirements].
    
 
    View all other issues in [allocator.requirements].
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
@@ -18111,21 +18626,20 @@ issue to Ready status to be voted into the WP at Kona.
 
 
    
 
    402. wrong new expression in [some_]allocator::construct
    
-
    Section: X [allocator.requirements], 20.8.4.1 [allocator.members] Status: CD1
+
    Section: 20.2.2 [allocator.requirements], 20.8.8.1 [allocator.members] Status: CD1
  Submitter: Markus Mauhart Opened: 2003-02-27  Last modified: 2008-09-26
    
-
    View other active issues in [allocator.requirements].
    
 
    View all other issues in [allocator.requirements].
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
 
    
 This applies to the new expression that is contained in both par12 of
-20.8.4.1 [allocator.members] and in par2 (table 32) of  [default.con.req].
+20.8.8.1 [allocator.members] and in par2 (table 32) of  [default.con.req].
 I think this new expression is wrong, involving unintended side
 effects.
 
    
 
 
-
    20.8.4.1 [allocator.members]  contains the following 3 lines:
    
+
    20.8.8.1 [allocator.members]  contains the following 3 lines:
    
 
 
      11 Returns: the largest value N for which the call allocate(N,0) might succeed.
      void construct(pointer p, const_reference val);
@@ -18303,13 +18817,13 @@ believed to be of limited value.
 
 
    
 
    405. qsort and POD
    
-
    Section: 25.6 [alg.c.library] Status: CD1
+
    Section: 25.5 [alg.c.library] Status: CD1
  Submitter: Ray Lischner Opened: 2003-04-08  Last modified: 2008-09-26
    
 
    View all other issues in [alg.c.library].
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
 
    
-Section 25.6 [alg.c.library] describes bsearch and qsort, from the C
+Section 25.5 [alg.c.library] describes bsearch and qsort, from the C
 standard library. Paragraph 4 does not list any restrictions on qsort,
 but it should limit the base parameter to point to POD.  Presumably,
 qsort sorts the array by copying bytes, which requires POD.
@@ -18318,7 +18832,7 @@ qsort sorts the array by copying bytes, which requires POD.
 
 
    Proposed resolution:
    
 
    
-In 25.6 [alg.c.library] paragraph 4, just after the declarations and
+In 25.5 [alg.c.library] paragraph 4, just after the declarations and
 before the nonnormative note, add these words: "both of which have the
 same behavior as the original declaration.  The behavior is undefined
 unless the objects in the array pointed to by base are of POD
@@ -18371,14 +18885,13 @@ existing implementation.
 
 
    
 
    407. Can singular iterators be destroyed?
    
-
    Section: 24.2 [iterator.concepts] Status: CD1
+
    Section: X [iterator.concepts] Status: CD1
  Submitter: Nathan Myers Opened: 2003-06-03  Last modified: 2008-09-30
    
-
    View other active issues in [iterator.concepts].
    
 
    View all other issues in [iterator.concepts].
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
 
    
-Clause 24.2 [iterator.concepts], paragraph 5, says that the only expression
+Clause X [iterator.concepts], paragraph 5, says that the only expression
 that is defined for a singular iterator is "an assignment of a
 non-singular value to an iterator that holds a singular value".  This 
 means that destroying a singular iterator (e.g. letting an automatic
@@ -18574,13 +19087,13 @@ supposed to do, but we ought to spell it out.
    
 
 
    
 
    411. Wrong names of set member functions
    
-
    Section: 25.5.5 [alg.set.operations] Status: CD1
+
    Section: 25.4.5 [alg.set.operations] Status: CD1
  Submitter: Daniel Frey Opened: 2003-07-09  Last modified: 2008-09-26
    
 
    View all other issues in [alg.set.operations].
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
 
    
-25.5.5 [alg.set.operations] paragraph 1 reads:
+25.4.5 [alg.set.operations] paragraph 1 reads:
 "The semantics of the set operations are generalized to multisets in a 
 standard way by defining union() to contain the maximum number of 
 occurrences of every element, intersection() to contain the minimum, and 
@@ -18878,6 +19391,124 @@ to match the type to which they refer.--end note]
 
 
 
+
    
+
    419. istream extractors not setting failbit if eofbit is already set
    
+
    Section: 27.7.1.1.3 [istream::sentry] Status: WP
+ Submitter: Martin Sebor Opened: 2003-09-18  Last modified: 2009-10-26
    
+
    View all other issues in [istream::sentry].
    
+
    View all issues with WP status.
    
+
    Discussion:
    
+        
    
+
+27.7.1.1.3 [istream::sentry], p2 says that istream::sentry ctor prepares for input if is.good()
+is true. p4 then goes on to say that the ctor sets the sentry::ok_ member to
+true if the stream state is good after any preparation. 27.7.1.2.1 [istream.formatted.reqmts], p1 then
+says that a formatted input function endeavors to obtain the requested input
+if the sentry's operator bool() returns true.
+
+Given these requirements, no formatted extractor should ever set failbit if
+the initial stream rdstate() == eofbit. That is contrary to the behavior of
+all implementations I tested. The program below prints out
+
+eof = 1, fail = 0
+eof = 1, fail = 1
+
+on all of them.
+        
    
+
    +#include <sstream>
+#include <cstdio>
+
+int main()
+{
+    std::istringstream strm ("1");
+
+    int i = 0;
+
+    strm >> i;
+
+    std::printf ("eof = %d, fail = %d\n",
+                 !!strm.eof (), !!strm.fail ());
+
+    strm >> i;
+
+    std::printf ("eof = %d, fail = %d\n",
+                 !!strm.eof (), !!strm.fail ());
+}
+
+
    
+        
    
+
    
+
+Comments from Jerry Schwarz (c++std-lib-11373):
+
    
+
+Jerry Schwarz wrote:
+
    
+
+I don't know where (if anywhere) it says it in the standard, but the
+formatted extractors are supposed to set failbit if they don't extract
+any characters. If they didn't then simple loops like
+
    
+
+while (cin >> x);
+
    
+
+would loop forever.
+
    
+
+Further comments from Martin Sebor:
+
    
+
+The question is which part of the extraction should prevent this from happening
+by setting failbit when eofbit is already set. It could either be the sentry
+object or the extractor. It seems that most implementations have chosen to
+set failbit in the sentry [...] so that's the text that will need to be
+corrected. 
+
+        
    
+
    
+Pre Berlin:  This issue is related to 342.  If the sentry
+sets failbit when it finds eofbit already set, then
+you can never seek away from the end of stream.
+
    
+
    Kona: Possibly NAD.  If eofbit is set then good() will return false.  We
+  then set ok to false.  We believe that the sentry's
+  constructor should always set failbit when ok is false, and
+  we also think the standard already says that.  Possibly it could be
+  clearer.
     
+
+
+
    [
+2009-07 Frankfurt
+]
    
+
+
+
    
+Moved to Ready.
+
    
+
+    
+
+
    Proposed resolution:
    
+
    
+Change 27.7.1.1.3 [istream::sentry], p2 to:
+
    
+
+
    
+
    explicit sentry(basic_istream<charT,traits>& is , bool noskipws = false);
    
+
    
+-2- Effects: If is.good() is true
+false, calls is.setstate(failbit). 
+Otherwise prepares for formatted or unformatted input. ...
+
    
+
    
+
+
+
+
+
+
 
    
 
    420. is std::FILE a complete type?
    
 
    Section: 27.9.1 [fstreams] Status: CD1
@@ -18982,7 +19613,7 @@ use the right wording.]
    
 
 
    
 
    425. return value of std::get_temporary_buffer
    
-
    Section: 20.8.7 [temporary.buffer] Status: CD1
+
    Section: 20.8.11 [temporary.buffer] Status: CD1
  Submitter: Martin Sebor Opened: 2003-09-18  Last modified: 2008-09-26
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
@@ -19008,7 +19639,7 @@ no storage can be obtained or if n <= 0."
    
 
 
    
 
    426. search_n(), fill_n(), and generate_n() with negative n
    
-
    Section: 25.3.12 [alg.search], 25.4.6 [alg.fill], 25.4.7 [alg.generate] Status: CD1
+
    Section: 25.2.12 [alg.search], 25.3.6 [alg.fill], 25.3.7 [alg.generate] Status: CD1
  Submitter: Martin Sebor Opened: 2003-09-18  Last modified: 2008-09-26
    
 
    View all other issues in [alg.search].
    
 
    View all issues with CD1 status.
    
@@ -19412,7 +20043,7 @@ initialized range.
    
 
 
    
 
    434. bitset::to_string() hard to use
    
-
    Section: 20.3.6.2 [bitset.members] Status: CD1
+
    Section: 20.3.7.2 [bitset.members] Status: CD1
  Submitter: Martin Sebor Opened: 2003-10-15  Last modified: 2009-05-01
    
 
    View all other issues in [bitset.members].
    
 
    View all issues with CD1 status.
    
@@ -19567,6 +20198,7 @@ text.]
    
 
    438. Ambiguity in the "do the right thing" clause
    
 
    Section: 23.2.3 [sequence.reqmts] Status: CD1
  Submitter: Howard Hinnant Opened: 2003-10-20  Last modified: 2009-05-01
    
+
    View other active issues in [sequence.reqmts].
    
 
    View all other issues in [sequence.reqmts].
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
@@ -20035,7 +20667,7 @@ LWG issue
 
 
    
 
    445. iterator_traits::reference unspecified for some iterator categories
    
-
    Section: D.10.1 [iterator.traits] Status: CD1
+
    Section: 24.4.1 [iterator.traits] Status: CD1
  Submitter: Dave Abrahams Opened: 2003-12-09  Last modified: 2009-05-01
    
 
    View all other issues in [iterator.traits].
    
 
    View all issues with CD1 status.
    
@@ -20133,7 +20765,7 @@ so I've changed the wording to say that those types may be
 
 
    Proposed resolution:
    
 
-
    In D.10.1 [iterator.traits], after:
    
+
    In 24.4.1 [iterator.traits], after:
    
 
 
    
 be defined as the iterator's difference type, value type and iterator
@@ -20152,7 +20784,7 @@ is, the same type as the type of *a and a->,
 respectively.
    
 
    
 
-
    In D.10.1 [iterator.traits], change:
    
+
    In 24.4.1 [iterator.traits], change:
    
 
 
    
 In the case of an output iterator, the types
    
@@ -20201,9 +20833,8 @@ needed to be changed.
 
 
    
 
    448. Random Access Iterators over abstract classes
    
-
    Section: 24.2.6 [random.access.iterators] Status: CD1
+
    Section: 24.2.5 [random.access.iterators] Status: CD1
  Submitter: Dave Abrahams Opened: 2004-01-07  Last modified: 2008-09-26
    
-
    View other active issues in [random.access.iterators].
    
 
    View all other issues in [random.access.iterators].
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
@@ -20461,7 +21092,7 @@ using-declarations (7.3.3 [namespace.udecl]).
 
    
 
 
    
-Change D.5 [depr.c.headers], para. 2-3:
+Change D.6 [depr.c.headers], para. 2-3:
 
    
 
 
    
@@ -20493,7 +21124,7 @@ names within the namespace std. -- end example]
 
 
    
 
    457. bitset constructor: incorrect number of initialized bits
    
-
    Section: 20.3.6.1 [bitset.cons] Status: CD1
+
    Section: 20.3.7.1 [bitset.cons] Status: CD1
  Submitter: Dag Henriksson Opened: 2004-01-30  Last modified: 2009-05-01
    
 
    View all other issues in [bitset.cons].
    
 
    View all issues with CD1 status.
    
@@ -20513,7 +21144,7 @@ guaranteed to have any corresponding bit values in val.
 
 
 
    Proposed resolution:
    
-
    In 20.3.6.1 [bitset.cons] paragraph 2, change "M is the smaller of
+
    In 20.3.7.1 [bitset.cons] paragraph 2, change "M is the smaller of
   N and the value CHAR_BIT * sizeof (unsigned long). (249)" to
   "M is the smaller of N and the number of bits in
   the value representation (section 3.9 [basic.types]) of unsigned
@@ -20671,7 +21302,6 @@ An implementation may also accept additional implementation-defined formats.
 
    464. Suggestion for new member functions in standard containers
    
 
    Section: 23.3.6 [vector], 23.4.1 [map] Status: CD1
  Submitter: Thorsten Ottosen Opened: 2004-05-12  Last modified: 2008-09-26
    
-
    View other active issues in [vector].
    
 
    View all other issues in [vector].
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
@@ -20923,7 +21553,6 @@ the value need not be valid.
 
    469. vector<bool> ill-formed relational operators
    
 
    Section: 23.3.6 [vector] Status: CD1
  Submitter: Martin Sebor Opened: 2004-06-28  Last modified: 2009-05-01
    
-
    View other active issues in [vector].
    
 
    View all other issues in [vector].
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
@@ -20973,7 +21602,7 @@ I propose to strike the Footnote.
 
 
    
 
    475. May the function object passed to for_each modify the elements of the iterated sequence?
    
-
    Section: 25.3.4 [alg.foreach] Status: CD1
+
    Section: 25.2.4 [alg.foreach] Status: CD1
  Submitter: Stephan T. Lavavej, Jaakko Jarvi Opened: 2004-07-09  Last modified: 2008-09-26
    
 
    View all other issues in [alg.foreach].
    
 
    View all issues with CD1 status.
    
@@ -21038,7 +21667,7 @@ passed to for_each modify its argument.
    
 
 
 
    Proposed resolution:
    
-
    Add a nonnormative note to the Effects in 25.3.4 [alg.foreach]: If
+
    Add a nonnormative note to the Effects in 25.2.4 [alg.foreach]: If
 the type of 'first' satisfies the requirements of a mutable iterator,
 'f' may apply nonconstant functions through the dereferenced iterators
 passed to it.
@@ -21058,7 +21687,7 @@ passed to it.
 
 
    
 
    478. Should forward iterator requirements table have a line for r->m?
    
-
    Section: 24.2.4 [forward.iterators] Status: CD1
+
    Section: 24.2.3 [forward.iterators] Status: CD1
  Submitter: Dave Abrahams Opened: 2004-07-11  Last modified: 2008-09-26
    
 
    View all other issues in [forward.iterators].
    
 
    View all issues with CD1 status.
    
@@ -21127,7 +21756,7 @@ This is a defect because it constrains an lvalue to returning a modifiable lvalu
 
 
    
 
    488. rotate throws away useful information
    
-
    Section: 25.4.11 [alg.rotate] Status: CD1
+
    Section: 25.3.11 [alg.rotate] Status: CD1
  Submitter: Howard Hinnant Opened: 2004-11-22  Last modified: 2008-09-26
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
@@ -21176,14 +21805,14 @@ a significant benefit to the change.
                 ForwardIterator last);
 
    
 
-
    In 25.4.11 [alg.rotate], change:
    
+
    In 25.3.11 [alg.rotate], change:
    
 
 
      template<class ForwardIterator>
     void ForwardIterator rotate(ForwardIterator first, ForwardIterator middle,
                 ForwardIterator last);
 
    
 
-
    In 25.4.11 [alg.rotate] insert a new paragraph after p1:
    
+
    In 25.3.11 [alg.rotate] insert a new paragraph after p1:
    
 
 
    
 
    Returns: first + (last - middle).
    
@@ -21291,7 +21920,6 @@ requirements of charT (described in 21 [strings]).
 
    496. Illegal use of "T" in vector<bool>
    
 
    Section: 23.3.6 [vector] Status: CD1
  Submitter: richard@ex-parrot.com Opened: 2005-02-10  Last modified: 2008-09-26
    
-
    View other active issues in [vector].
    
 
    View all other issues in [vector].
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
@@ -21375,6 +22003,152 @@ at runtime.
 
 
 
+
    
+
    498. Requirements for partition() and stable_partition() too strong
    
+
    Section: 25.3.13 [alg.partitions] Status: WP
+ Submitter: Sean Parent, Joe Gottman Opened: 2005-05-04  Last modified: 2009-10-26
    
+
    View all issues with WP status.
    
+
    Discussion:
    
+
    
+Problem:
+The iterator requirements for partition() and stable_partition() [25.2.12]
+are listed as BidirectionalIterator, however, there are efficient algorithms
+for these functions that only require ForwardIterator that have been known
+since before the standard existed. The SGI implementation includes these (see
+http://www.sgi.com/tech/stl/partition.html
+and
+http://www.sgi.com/tech/stl/stable_partition.html).
+
    
+
+
    [
+2009-04-30 Alisdair adds:
+]
    
+
+
+
    
+
    
+Now we have concepts this is easier to express!
+
    
+
    
+Proposed resolution:
+
    
+
    
+Add the following signature to:
+
    
+
    
+Header <algorithm> synopsis  [algorithms.syn]
    
+p3 Partitions 25.3.13 [alg.partitions]
+
    
+
     template<ForwardIterator Iter, Predicate<auto, Iter::value_type> Pred>
+   requires ShuffleIterator<Iter>
+         && CopyConstructible<Pred>
+   Iter partition(Iter first, Iter last, Pred pred);
+
    
+
+
    
+Update p3 Partitions 25.3.13 [alg.partitions]:
+
    
+
+
    
+
    
+Complexity: At most (last - first)/2 swaps. Exactly last - first
+applications of the predicate
+are done.
+
+If Iter satisfies BidirectionalIterator, at most (last -
+first)/2 swaps. Exactly last - first applications of the predicate
+are done.
+
+
    
+
    
+If Iter merely satisfied ForwardIterator at most (last - first) swaps
+are done. Exactly (last - first) applications of the predicate are done.
+
    
+
    
+
+
    
+[Editorial note: I looked for existing precedent in how we might call out
+distinct overloads overloads from a set of constrained templates, but there
+is not much existing practice to lean on.   advance/distance were the only
+algorithms I could find, and that wording is no clearer.]
+
    
+
+
    
+
+
    [
+2009-07 Frankfurt
+]
    
+
+
+
    
+
    
+Hinnant: if you want to partition your std::forward_list, you'll need
+partition() to accept ForwardIterators.
+
    
+
    
+No objection to Ready.
+
    
+
    
+Move to Ready.
+
    
+
    
+
+
+
+
    Proposed resolution:
    
+
    
+Change 25.2.12 from 
    
+
    template<class BidirectionalIterator, class Predicate> 
+BidirectionalIterator partition(BidirectionalIterato r first, 
+                                BidirectionalIterator last, 
+                                Predicate pred); 
+
    
+
    to 
    
+
    template<class ForwardIterator, class Predicate> 
+ForwardIterator partition(ForwardIterator first, 
+                          ForwardIterator last, 
+                          Predicate pred); 
+
    
+
    Change the complexity from 
    
+
+
    
+At most (last - first)/2 swaps are done. Exactly (last - first) 
+applications of the predicate are done. 
+
    
+
+
    to 
    
+
+
    
+If ForwardIterator is a bidirectional_iterator, at most (last - first)/2 
+swaps are done; otherwise at most (last - first) swaps are done. Exactly 
+(last - first) applications of the predicate are done. 
+
    
+
+
+
+
    Rationale:
    
+
    
+Partition is a "foundation" algorithm useful in many contexts (like sorting
+as just one example) - my motivation for extending it to include forward
+iterators is foward_list - without this extension you can't partition an foward_list
+(without writing your own partition). Holes like this in the standard
+library weaken the argument for generic programming (ideally I'd be able
+to provide a library that would refine std::partition() to other concepts
+without fear of conflicting with other libraries doing the same - but
+that is a digression). I consider the fact that partition isn't defined
+to work for ForwardIterator a minor embarrassment.
+
    
+
+
    [Mont Tremblant: Moved to Open, request motivation and use cases
+by next meeting. Sean provided further rationale by post-meeting
+mailing.]
    
+
+
+
+
+
+
+
 
    
 
    505. Result_type in random distribution requirements
    
 
    Section: X [rand.req], TR1 5.1.1 [tr.rand.req] Status: CD1
@@ -21615,7 +22389,6 @@ preserves the relative ordering of equivalent elements.
    
 
    519. Data() undocumented
    
 
    Section: 23.3.1 [array], TR1 6.2.2 [tr.array.array] Status: CD1
  Submitter: Pete Becker Opened: 2005-07-03  Last modified: 2008-09-26
    
-
    View other active issues in [array].
    
 
    View all other issues in [array].
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
@@ -21648,7 +22421,7 @@ of data() is unspecified.
 
 
    
 
    520. Result_of and pointers to data members
    
-
    Section: 20.7.12.1 [func.bind], TR1 3.6 [tr.func.bind] Status: CD1
+
    Section: 20.7.11.1 [func.bind], TR1 3.6 [tr.func.bind] Status: CD1
  Submitter: Pete Becker Opened: 2005-07-03  Last modified: 2008-09-26
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
@@ -21942,7 +22715,7 @@ The LWG voted to accelerate this issue to Ready status to be voted into the WP a
 
 
    
 
    527. tr1::bind has lost its Throws clause
    
-
    Section: 20.7.12.1.3 [func.bind.bind], TR1 3.6.3 [tr.func.bind.bind] Status: CD1
+
    Section: 20.7.11.1.3 [func.bind.bind], TR1 3.6.3 [tr.func.bind.bind] Status: CD1
  Submitter: Peter Dimov Opened: 2005-10-01  Last modified: 2008-09-26
    
 
    View other active issues in [func.bind.bind].
    
 
    View all other issues in [func.bind.bind].
    
@@ -22010,7 +22783,7 @@ throws an exception.
 
 
    Proposed resolution:
    
 
    
-In 20.7.12.1.3 [func.bind.bind], add a new paragraph after p2:
+In 20.7.11.1.3 [func.bind.bind], add a new paragraph after p2:
 
    
 
 
    
@@ -22019,7 +22792,7 @@ in the BoundArgs... pack expansion throws an exception.
 
    
 
 
    
-In 20.7.12.1.3 [func.bind.bind], add a new paragraph after p4:
+In 20.7.11.1.3 [func.bind.bind], add a new paragraph after p4:
 
    
 
 
    
@@ -22163,7 +22936,7 @@ writing to out of bounds memory when n == 0.  Martin provided fix.
 
 
    
 
    533. typo in 2.2.3.10/1
    
-
    Section: 20.8.10.2.11 [util.smartptr.getdeleter], TR1 2.2.3.10 [tr.util.smartptr.getdeleter] Status: CD1
+
    Section: 20.8.15.2.11 [util.smartptr.getdeleter], TR1 2.2.3.10 [tr.util.smartptr.getdeleter] Status: CD1
  Submitter: Paolo Carlini Opened: 2005-11-09  Last modified: 2009-05-01
    
 
    View all other issues in [util.smartptr.getdeleter].
    
 
    View all issues with CD1 status.
    
@@ -22429,7 +23202,7 @@ After 27.6.2.4p3 change:
 
 
    
 
    538. 241 again: Does unique_copy() require CopyConstructible and Assignable?
    
-
    Section: 25.4.9 [alg.unique] Status: CD1
+
    Section: 25.3.9 [alg.unique] Status: CD1
  Submitter: Howard Hinnant Opened: 2006-02-09  Last modified: 2008-09-26
    
 
    View all other issues in [alg.unique].
    
 
    View all issues with CD1 status.
    
@@ -22487,7 +23260,7 @@ Otherwise CopyConstructible is not required.
 
 
    
 
    540. shared_ptr<void>::operator*()
    
-
    Section: 20.8.10.2.5 [util.smartptr.shared.obs], TR1 2.2.3.5 [tr.util.smartptr.shared.obs] Status: CD1
+
    Section: 20.8.15.2.5 [util.smartptr.shared.obs], TR1 2.2.3.5 [tr.util.smartptr.shared.obs] Status: CD1
  Submitter: Martin Sebor Opened: 2005-10-15  Last modified: 2008-09-26
    
 
    View all other issues in [util.smartptr.shared.obs].
    
 
    View all issues with CD1 status.
    
@@ -22545,9 +23318,8 @@ definition) of the function shall be well-formed.
 
 
    
 
    541. shared_ptr template assignment and void
    
-
    Section: 20.8.10.2 [util.smartptr.shared], TR1 2.2.3 [tr.util.smartptr.shared] Status: CD1
+
    Section: 20.8.15.2 [util.smartptr.shared], TR1 2.2.3 [tr.util.smartptr.shared] Status: CD1
  Submitter: Martin Sebor Opened: 2005-10-16  Last modified: 2008-09-26
    
-
    View other active issues in [util.smartptr.shared].
    
 
    View all other issues in [util.smartptr.shared].
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
@@ -22626,7 +23398,7 @@ public:
 
 
    
 
    542. shared_ptr observers
    
-
    Section: 20.8.10.2.5 [util.smartptr.shared.obs], TR1 2.2.3.5 [tr.util.smartptr.shared.obs] Status: CD1
+
    Section: 20.8.15.2.5 [util.smartptr.shared.obs], TR1 2.2.3.5 [tr.util.smartptr.shared.obs] Status: CD1
  Submitter: Martin Sebor Opened: 2005-10-18  Last modified: 2008-09-26
    
 
    View all other issues in [util.smartptr.shared.obs].
    
 
    View all issues with CD1 status.
    
@@ -22666,7 +23438,7 @@ capture the intent.
 
 
    Proposed resolution:
    
 
    
-Change 20.8.10.2.5 [util.smartptr.shared.obs] p12:
+Change 20.8.15.2.5 [util.smartptr.shared.obs] p12:
 
    
 
    
 [Note: use_count() is not necessarily efficient. Use only for
@@ -22674,7 +23446,7 @@ debugging and testing purposes, not for production code. --end note
 
    
 
 
    
-Change 20.8.10.3.5 [util.smartptr.weak.obs] p3:
+Change 20.8.15.3.5 [util.smartptr.weak.obs] p3:
 
    
 
    
 [Note: use_count() is not necessarily efficient. Use only for
@@ -22763,7 +23535,7 @@ lengths, and strides, as explained in the previous section.
 
 
    
 
    545. When is a deleter deleted?
    
-
    Section: 20.8.10.2.11 [util.smartptr.getdeleter], TR1 2.2.3.2 [tr.util.smartptr.shared.dest] Status: CD1
+
    Section: 20.8.15.2.11 [util.smartptr.getdeleter], TR1 2.2.3.2 [tr.util.smartptr.shared.dest] Status: CD1
  Submitter: Matt Austern Opened: 2006-01-10  Last modified: 2008-09-26
    
 
    View all other issues in [util.smartptr.getdeleter].
    
 
    View all issues with CD1 status.
    
@@ -22781,7 +23553,7 @@ instances). We should say which it is.
 
 
    Proposed resolution:
    
 
    
-Add after the first sentence of 20.8.10.2.11 [util.smartptr.getdeleter]/1:
+Add after the first sentence of 20.8.15.2.11 [util.smartptr.getdeleter]/1:
 
    
 
    
 
    
@@ -23000,7 +23772,7 @@ note]
 
 
    
 
    552. random_shuffle and its generator
    
-
    Section: 25.4.12 [alg.random.shuffle] Status: CD1
+
    Section: 25.3.12 [alg.random.shuffle] Status: CD1
  Submitter: Martin Sebor Opened: 2006-01-25  Last modified: 2008-09-26
    
 
    View all other issues in [alg.random.shuffle].
    
 
    View all issues with CD1 status.
    
@@ -23117,7 +23889,7 @@ automatically.
 
 
    
 
    561. inserter overly generic
    
-
    Section: 24.7.6.5 [inserter] Status: CD1
+
    Section: 24.5.2.6.5 [inserter] Status: CD1
  Submitter: Howard Hinnant Opened: 2006-02-21  Last modified: 2008-09-26
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
@@ -23434,6 +24206,160 @@ Kona (2007) Moved to Ready.
 
 
 
+
    
+
    564. stringbuf seekpos underspecified
    
+
    Section: 27.8.1.4 [stringbuf.virtuals] Status: WP
+ Submitter: Martin Sebor Opened: 2006-02-23  Last modified: 2009-10-26
    
+
    View all other issues in [stringbuf.virtuals].
    
+
    View all issues with WP status.
    
+
    Discussion:
    
+
    
+The   effects  of  the   seekpos()  member   function  of
+basic_stringbuf  simply say  that the  function positions
+the  input and/or  output  sequences  but fail  to  spell out  exactly
+how. This is in contrast  to the detail in which seekoff()
+is described.
+
    
+
+
    [
+2009-07 Frankfurt
+]
    
+
+
+
    
+Move to Ready.
+
    
+
+
+
+
    Proposed resolution:
    
+        
    
+
+Change 27.7.1.3, p13 to read:
+
+        
    
+
    
+
    
+-13- Effects: Equivalent to seekoff(off_type(sp), ios_base::beg,
+which). Alters the stream position within the controlled sequences,
+if possible, to correspond to the stream position stored in sp
+(as described below).
+
    
+
      
+
    • If (which & ios_base::in) != 0, positions the input sequence.
      • 
+
    • If (which & ios_base::out) != 0, positions the output sequence.
      • 
+
    • If sp is an invalid stream position, or if the function
+positions neither sequence, the positioning operation fails. If sp
+has not been obtained by a previous successful call to one of the positioning
+functions (seekoff, seekpos, tellg, tellp)
+the effect is undefined.
      • 
+
    
+
    
+
+
+
    [
+Kona (2007): A pos_type is a position in a stream by
+definition, so there is no ambiguity as to what it means. Proposed
+Disposition: NAD
+]
    
+
+
+
    [
+Post-Kona Martin adds:
+I'm afraid I disagree
+with the Kona '07 rationale for marking it NAD. The only text
+that describes precisely what it means to position the input
+or output sequence is in seekoff(). The seekpos() Effects
+clause is inadequate in comparison and the proposed resolution
+plugs the hole by specifying seekpos() in terms of seekoff().
+]
    
+
+
+
+
+
+
    
+
    565. xsputn inefficient
    
+
    Section: 27.6.2.4.5 [streambuf.virt.put] Status: WP
+ Submitter: Martin Sebor Opened: 2006-02-23  Last modified: 2009-10-26
    
+
    View all issues with WP status.
    
+
    Discussion:
    
+        
    
+
+streambuf::xsputn()  is  specified  to  have  the  effect  of
+"writing up to  n characters to the output  sequence as if by
+repeated calls to sputc(c)."
+
+        
    
+        
    
+
+Since  sputc() is required  to call  overflow() when
+(pptr()    ==   epptr())    is   true,    strictly   speaking
+xsputn()  should do  the same.   However, doing  so  would be
+suboptimal in  some interesting cases,  such as in unbuffered  mode or
+when the buffer is basic_stringbuf.
+
+        
    
+        
    
+
+Assuming  calling overflow()  is  not really  intended to  be
+required  and the  wording is  simply  meant to  describe the  general
+effect of appending to the end  of the sequence it would be worthwhile
+to  mention in  xsputn() that  the function  is  not actually
+required to cause a call to overflow().
+
+        
    
+
+
    [
+2009-07 Frankfurt
+]
    
+
+
+
    
+Move to Ready.
+
    
+
+
+
+
    Proposed resolution:
    
+        
    
+
+Add the following sentence  to the xsputn() Effects clause in
+27.5.2.4.5, p1 (N1804):
+
+        
    
+        
        
+            
    
+-1- Effects: Writes up to n characters to the output
+sequence as if by repeated calls to sputc(c). The characters 
+written are obtained from successive elements of the array whose first element
+is designated by s. Writing stops when either n
+characters have been written or a call to sputc(c) would return
+traits::eof(). It is  uspecified whether the function  calls
+overflow() when (pptr() ==  epptr()) becomes true or whether
+it achieves the same effects by other means.
+            
    
+        
        
+        
    
+
+In addition,  I suggest to  add a footnote  to this function  with the
+same text as Footnote 292 to  make it extra clear that derived classes
+are permitted to override xsputn() for efficiency.
+
+        
    
+
+
+
    [
+Kona (2007): We want to permit a streambuf that streams output directly
+to a device without making calls to sputc or overflow. We believe that
+has always been the intention of the committee. We believe that the
+proposed wording doesn't accomplish that. Proposed Disposition: Open
+]
    
+
+
+
+
+
 
    
 
    566. array forms of unformatted input function undefined for zero-element arrays
    
 
    Section: 27.7.1.3 [istream.unformatted] Status: CD1
@@ -23627,7 +24553,7 @@ Disposition: Review
 
 
    
 
    575. the specification of ~shared_ptr is MT-unfriendly, makes implementation assumptions
    
-
    Section: 20.8.10.2.2 [util.smartptr.shared.dest], TR1 2.2.3.2 [tr.util.smartptr.shared.dest] Status: CD1
+
    Section: 20.8.15.2.2 [util.smartptr.shared.dest], TR1 2.2.3.2 [tr.util.smartptr.shared.dest] Status: CD1
  Submitter: Peter Dimov Opened: 2006-04-23  Last modified: 2008-09-26
    
 
    View all other issues in [util.smartptr.shared.dest].
    
 
    View all issues with CD1 status.
    
@@ -23706,7 +24632,7 @@ after *this is destroyed. --end note]
 
 
    
 
    576. find_first_of is overconstrained
    
-
    Section: 25.3.7 [alg.find.first.of] Status: CD1
+
    Section: 25.2.7 [alg.find.first.of] Status: CD1
  Submitter: Doug Gregor Opened: 2006-04-25  Last modified: 2008-09-26
    
 
    View all other issues in [alg.find.first.of].
    
 
    View all issues with CD1 status.
    
@@ -23759,7 +24685,7 @@ template<class ForwardIterator1InputIterator1, class Fo
 
 
    
 
    577. upper_bound(first, last, ...) cannot return last
    
-
    Section: 25.5.3.2 [upper.bound] Status: CD1
+
    Section: 25.4.3.2 [upper.bound] Status: CD1
  Submitter: Seungbeom Kim Opened: 2006-05-03  Last modified: 2008-09-26
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
@@ -23809,7 +24735,7 @@ conditions hold: !(value < *j) or comp(value, *j)
 
 
    
 
    578. purpose of hint to allocator::allocate()
    
-
    Section: 20.8.4.1 [allocator.members] Status: CD1
+
    Section: 20.8.8.1 [allocator.members] Status: CD1
  Submitter: Martin Sebor Opened: 2006-05-17  Last modified: 2008-09-26
    
 
    View all other issues in [allocator.members].
    
 
    View all issues with CD1 status.
    
@@ -25068,7 +25994,7 @@ and accept my apologies for the oversight.
 
 
    
 
    610. Suggested non-normative note for C++0x
    
-
    Section: 20.7.16.2.1 [func.wrap.func.con], TR1 3.7.2.1 [tr.func.wrap.func.con] Status: CD1
+
    Section: 20.7.15.2.1 [func.wrap.func.con], TR1 3.7.2.1 [tr.func.wrap.func.con] Status: CD1
  Submitter: Scott Meyers Opened: 2006-11-02  Last modified: 2008-09-26
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
@@ -25705,7 +26631,7 @@ dtor? Should the  dtor catch and swallow it or  should it propagate it
 to the caller?  The text doesn't  seem to provide any guidance in this
 regard  other  than  the  general  restriction on  throwing  (but  not
 propagating)  exceptions  from   destructors  of  library  classes  in
-17.6.4.10 [res.on.exception.handling].
+17.6.4.11 [res.on.exception.handling].
 
         
    
         
    
@@ -25820,7 +26746,7 @@ And to make the following edits in 27.9.1.2 [filebuf.cons].
 close().    If  an   exception  occurs   during  the
 destruction of the object, including the call to close(),
 the     exception    is     caught    but     not     rethrown    (see
-17.6.4.10 [res.on.exception.handling]).
+17.6.4.11 [res.on.exception.handling]).
 
             
    
         
    
@@ -26123,9 +27049,185 @@ will extract unambiguously.]
 
 
 
+
    
+
    630. arrays of valarray
    
+
    Section: 26.6.2.1 [valarray.cons] Status: WP
+ Submitter: Martin Sebor Opened: 2007-01-28  Last modified: 2009-10-26
    
+
    View all other issues in [valarray.cons].
    
+
    View all issues with WP status.
    
+
    Discussion:
    
+        
    
+
+Section 26.2 [numeric.requirements], p1     suggests     that     a
+valarray  specialization on  a  type T  that
+satisfies  the requirements enumerated  in the  paragraph is  itself a
+valid  type   on  which  valarray   may  be  instantiated
+(Footnote       269        makes       this       clear).        I.e.,
+valarray<valarray<T>  > is  valid as  long as
+T   is   valid.    However,  since   implementations   of
+valarray are permitted to initialize storage allocated by
+the class by  invoking the default ctor of  T followed by
+the    copy    assignment    operator,   such    implementations    of
+valarray   wouldn't  work  with   (perhaps  user-defined)
+specializations of valarray whose assignment operator had
+undefined behavior when the size of its argument didn't match the size
+of *this.  By "wouldn't work" I mean that it would
+be  impossible  to resize  such  an array  of  arrays  by calling  the
+resize() member  function on it if the  function used the
+copy  assignment operator  after constructing  all elements  using the
+default  ctor (e.g.,  by invoking  new  value_type[N]) to
+obtain default-initialized storage) as it's permitted to do.
+
+        
    
+        
    
+
+Stated      more     generally,      the      problem     is      that
+valarray<valarray<T>  >::resize(size_t) isn't
+required or  guaranteed to have well-defined semantics  for every type
+T     that      satisfies     all     requirements     in
+26.2 [numeric.requirements].
+
+        
    
+        
    
+
+I  believe  this  problem  was  introduced  by  the  adoption  of  the
+resolution                outlined                in                N0857,
+Assignment  of  valarrays,  from  1996.   The  copy  assignment
+operator  of  the original  numerical  array  classes  proposed in  N0280,
+as      well       as      the      one       proposed      in      N0308
+(both  from 1993), had  well-defined semantics  for arrays  of unequal
+size (the  latter explicitly  only when *this  was empty;
+assignment of non empty arrays of unequal size was a runtime error).
+
+        
    
+        
    
+
+The  justification for  the  change given  in  N0857 was the "loss  of
+performance [deemed]  only significant  for very simple  operations on
+small arrays or for architectures with very few registers."
+
+        
    
+        
    
+
+Since tiny  arrays on a  limited subset of hardware  architectures are
+likely  to  be  an   exceedingly  rare  case  (despite  the  continued
+popularity of  x86) I  propose to revert  the resolution and  make the
+behavior    of   all   valarray    assignment   operators
+well-defined even  for non-conformal  arrays (i.e., arrays  of unequal
+size).   I have implemented  this change  and measured  no significant
+degradation  in performance in  the common  case (non-empty  arrays of
+equal size).  I  have measured a 50% (and in  some cases even greater)
+speedup  in the  case of  assignments to  empty arrays  versus calling
+resize()  first followed  by  an invocation  of the  copy
+assignment operator.
+
+        
    
+
+
    [
+Bellevue:
+]
    
+
+
+
    
+If no proposed wording by June meeting, this issue should be closed NAD.
+
    
+
+
    [
+2009-07 Frankfurt
+]
    
+
+
+
    
+
    
+Move resolution 1 to Ready.
+
    
+
    
+Howard: second resolution has been commented out (made invisible).
+Can be brought back on demand.
+
    
+
    
+
+
+
+
    Proposed resolution:
    
+        
    
+
+Change 26.6.2.2 [valarray.assign], p1 as follows:
+
+        
    
+        
    
+            
    
+                
+
+valarray<T>& operator=(const valarray<T>& x);
+
+                
+            
    
+            
    
+
+-1- Each element of the *this array is assigned the value
+of  the  corresponding  element   of  the  argument  array.   The
+resulting behavior is undefined if When the length of
+the  argument  array  is  not   equal  to  the  length  of  the  *this
+array.  resizes  *this  to make  the  two
+arrays     the      same     length,     as      if     by     calling
+resize(x.size()), before performing the assignment.
+
+            
    
+        
    
+        
    
+
+And  add a new  paragraph just  below paragraph  1 with  the following
+text:
+
+        
    
+        
    
+            
    
+
+-2- Postcondition: size() == x.size().
+
+            
    
+        
    
+        
    
+
+Also add the following paragraph to 26.6.2.2 [valarray.assign], immediately after p4:
+
+        
    
+        
    
+            
    
+
+-?- When the length,  N of the array referred
+to by the  argument is not equal to  the length of *this,
+the  operator resizes *this  to make  the two  arrays the
+same  length, as if  by calling  resize(N), before
+performing the assignment.
+
+            
    
+        
    
+
+
    [
+pre-Sophia Antipolis, Martin adds the following compromise wording, but
+prefers the original proposed resolution:
+]
    
+
+
+
+
+
+
+
    [
+Kona (2007): Gaby to propose wording for an alternative resolution in
+which you can assign to a valarray of size 0, but not to any other
+valarray whose size is unequal to the right hand side of the assignment.
+]
    
+
+
+
+
+
 
    
 
    634. allocator.address() doesn't work for types overloading operator&
    
-
    Section: 20.8.4.1 [allocator.members] Status: CD1
+
    Section: 20.8.8.1 [allocator.members] Status: CD1
  Submitter: Howard Hinnant Opened: 2007-02-07  Last modified: 2008-09-26
    
 
    View all other issues in [allocator.members].
    
 
    View all issues with CD1 status.
    
@@ -26133,7 +27235,7 @@ will extract unambiguously.]
 
    Discussion:
    
 
 
    
-20.8.4.1 [allocator.members] says:
+20.8.8.1 [allocator.members] says:
 
    
 
    
 
    pointer address(reference x) const;
    
@@ -26145,7 +27247,7 @@ will extract unambiguously.]
 
    
 
 
    
-20.8.4.1 [allocator.members] defines CopyConstructible which currently not
+20.8.8.1 [allocator.members] defines CopyConstructible which currently not
 only defines the semantics of copy construction, but also restricts what an overloaded
 operator& may do.  I believe proposals are in the works (such as concepts
 and rvalue reference) to decouple these two requirements.  Indeed it is not evident
@@ -26168,7 +27270,7 @@ On the other hand, some code truly needs the address of an object, and not a pro
 boost::addressof.
 It appears to me that this would be useful functionality for the default allocator.  Adopting
 this definition for allocator::address would free the standard of requiring
-anything special from types which overload operator&.  Issue 580
+anything special from types which overload operator&.  Issue 580
 is expected to make use of allocator::address mandatory for containers.
 
    
 
@@ -26176,7 +27278,7 @@ is expected to make use of allocator::address mandatory for containers.
 
 
    Proposed resolution:
    
 
    
-Change 20.8.4.1 [allocator.members]:
+Change 20.8.8.1 [allocator.members]:
 
    
 
 
    
@@ -26786,6 +27888,207 @@ The LWG voted to accelerate this issue to Ready status to be voted into the WP a
 
 
 
+
    
+
    659. istreambuf_iterator should have an operator->()
    
+
    Section: 24.6.3 [istreambuf.iterator] Status: WP
+ Submitter: Niels Dekker Opened: 2007-03-25  Last modified: 2009-10-26
    
+
    View all other issues in [istreambuf.iterator].
    
+
    View all issues with WP status.
    
+
    Discussion:
    
+
    
+Greg Herlihy has clearly demonstrated that a user defined input
+iterator should have an operator->(), even if its
+value type is a built-in type (comp.std.c++, "Re: Should any iterator
+have an operator->() in C++0x?", March 2007).  And as Howard
+Hinnant remarked in the same thread that the input iterator
+istreambuf_iterator doesn't have one, this must be a
+defect!
+
    
+
    
+Based on Greg's example, the following code demonstrates the issue:
+
     #include <iostream> 
+ #include <fstream>
+ #include <streambuf> 
+
+ typedef char C;
+ int main ()
+ {
+   std::ifstream s("filename", std::ios::in);
+   std::istreambuf_iterator<char> i(s);
+
+   (*i).~C();  // This is well-formed...
+   i->~C();  // ... so this should be supported!
+ }
+
    
+
+
    
+Of course, operator-> is also needed when the value_type of
+istreambuf_iterator is a class.
+
    
+
    
+The operator-> could be implemented in various ways.  For instance,
+by storing the current value inside the iterator, and returning its
+address.  Or by returning a proxy, like operator_arrow_proxy, from
+http://www.boost.org/boost/iterator/iterator_facade.hpp
+
    
+
    
+I hope that the resolution of this issue will contribute to getting a
+clear and consistent definition of iterator concepts.
+
    
+
+
    [
+Kona (2007): The proposed resolution is inconsistent because the return
+type of istreambuf_iterator::operator->() is specified to be pointer,
+but the proposed text also states that "operator-> may return a proxy."
+]
    
+
+
+
    [
+Niels Dekker (mailed to Howard Hinnant):
+]
    
+
+
    
+
    
+The proposed resolution does
+not seem inconsistent to me. istreambuf_iterator::operator->() should
+have istreambuf_iterator::pointer as return type, and this return type
+may in fact be a proxy.
+
    
+
    
+AFAIK, the resolution of 445 ("iterator_traits::reference
+unspecified for some iterator categories") implies that for any iterator
+class Iter, the return type of operator->() is Iter::pointer, by
+definition.  I don't think Iter::pointer needs to be a raw pointer.
+
    
+
    
+Still I wouldn't mind if the text "operator-> may return a proxy" would
+be removed from the resolution. I think it's up to the library
+implementation, how to implement istreambuf_iterator::operator->().  As
+longs as it behaves as expected: i->m should have the same effect as
+(*i).m. Even for an explicit destructor call, i->~C().  The main issue
+is just: istreambuf_iterator should have an operator->()!
+
    
+
    
+
+
    [
+2009-04-30 Alisdair adds:
+]
    
+
+
+
    
+Note that operator-> is now a requirement in the InputIterator concept, so
+this issue cannot be ignored or existing valid programs will break when
+compiled with an 0x library.
+
    
+
+
    [
+2009-05-29 Alisdair adds:
+]
    
+
+
+
    
+
    
+I agree with the observation that in principle the type 'pointer' may be a
+proxy, and the words highlighting this are redundant.
+
    
+
    
+However, in the current draught pointer is required to be exactly 'charT *'
+by the derivation from std::iterator.  At a minimum, the 4th parameter of
+this base class template should become unspecified.  That permits the
+introduction of a proxy as a nested class in some further undocumented (not
+even exposition-only) base.
+
    
+
    
+It also permits the istream_iterator approach where the cached value is
+stored in the iterator itself, and the iterator serves as its own proxy for
+post-increment operator++ - removing the need for the existing
+exposition-only nested class proxy.
+
    
+
    
+Note that the current proxy class also has exactly the right properties to
+serve as the pointer proxy too.  This is likely to be a common case where an
+InputIterator does not hold internal state but delegates to another class.
+
    
+
    
+Proposed Resolution:
+
    
+
    
+In addition to the current proposal:
+
    
+
    
+24.6.3 [istreambuf.iterator]
+
    
+
    template<class charT, class traits = char_traits<charT> >
+class istreambuf_iterator
+  : public iterator<input_iterator_tag, charT,
+                    typename traits::off_type, charT* unspecified, charT> {
+
    
+
    
+
+
    [
+2009-07 Frankfurt
+]
    
+
+
+
    
+
    
+Move the additional part into the proposed resolution, and wrap the
+descriptive text in a Note.
+
    
+
    [Howard: done.]
    
+
+
    
+Move to Ready.
+
    
+
    
+
+
+
+
    Proposed resolution:
    
+
    
+Add to the synopsis in 24.6.3 [istreambuf.iterator]:
+
    
+
+
    charT operator*() const;
+pointer operator->() const;
+istreambuf_iterator<charT,traits>& operator++();
+
    
+
+
    
+24.6.3 [istreambuf.iterator]
+
    
+
+
    template<class charT, class traits = char_traits<charT> >
+class istreambuf_iterator
+  : public iterator<input_iterator_tag, charT,
+                    typename traits::off_type, charT* unspecified, charT> {
+
    
+
+
    
+Change 24.6.3 [istreambuf.iterator], p1:
+
    
+
+
    
+The class template istreambuf_iterator reads successive
+characters from the streambuf for which it was constructed.
+operator* provides access to the current input character, if
+any. [Note: operator-> may return a proxy. —
+end note] Each time
+operator++ is evaluated, the iterator advances to the next
+input character. If the end of stream is reached
+(streambuf_type::sgetc() returns traits::eof()), the
+iterator becomes equal to the end of stream iterator value. The default
+constructor istreambuf_iterator() and the constructor
+istreambuf_iterator(0) both construct an end of stream iterator
+object suitable for use as an end-of-range.
+
    
+
+
+
+
+
+
+
 
    
 
    660. Missing Bitwise Operations
    
 
    Section: 20.7 [function.objects] Status: CD1
@@ -27088,7 +28391,7 @@ four characters long, usually three letters and a space.
 
 
    
 
    672. Swappable requirements need updating
    
-
    Section: X [utility.arg.requirements] Status: CD1
+
    Section: 20.2.1 [utility.arg.requirements] Status: CD1
  Submitter: Howard Hinnant Opened: 2007-05-04  Last modified: 2008-09-26
    
 
    View other active issues in [utility.arg.requirements].
    
 
    View all other issues in [utility.arg.requirements].
    
@@ -27179,7 +28482,7 @@ between two different types for the case that one is binding to a user-defined <
 
    Proposed resolution:
    
 
 
    
-Change X [utility.arg.requirements]:
+Change 20.2.1 [utility.arg.requirements]:
 
    
 
 
    
@@ -27248,7 +28551,7 @@ swap to be rvalues).
 
 
    
 
    673. unique_ptr update
    
-
    Section: 20.8.9 [unique.ptr] Status: CD1
+
    Section: 20.8.14 [unique.ptr] Status: CD1
  Submitter: Howard Hinnant Opened: 2007-05-04  Last modified: 2008-09-26
    
 
    View all other issues in [unique.ptr].
    
 
    View all issues with CD1 status.
    
@@ -27370,7 +28673,7 @@ the proposed resolutions below.
 
  • 
 
 
    
-Change 20.8.9.2 [unique.ptr.single]:
+Change 20.8.14.2 [unique.ptr.single]:
 
    
 
 
    template <class T, class D = default_delete<T>> class unique_ptr {
@@ -27381,7 +28684,7 @@ Change 20.8.9.2 [unique.ptr.single]:
 
    
 
 
    
-Change 20.8.9.2.4 [unique.ptr.single.observers]:
+Change 20.8.14.2.4 [unique.ptr.single.observers]:
 
    
 
 
    T& typename add_lvalue_reference<T>::type operator*() const;
@@ -27391,7 +28694,7 @@ Change 20.8.9.2.4 [unique.ptr.single.observers]:
 
 
  • 
 
    
-Change 20.8.9.2 [unique.ptr.single]:
+Change 20.8.14.2 [unique.ptr.single]:
 
    
 
 
    template <class T, class D = default_delete<T>> class unique_ptr {
@@ -27423,7 +28726,7 @@ and CopyAssignable.
 
    
 
 
    
-Change 20.8.9.2.1 [unique.ptr.single.ctor]:
+Change 20.8.14.2.1 [unique.ptr.single.ctor]:
 
    
 
 
    unique_ptr(T* pointer p);
@@ -27463,7 +28766,7 @@ internally stored deleter which was constructed from
 
    
 
 
    
-Change 20.8.9.2.3 [unique.ptr.single.asgn]:
+Change 20.8.14.2.3 [unique.ptr.single.asgn]:
 
    
 
 
    
@@ -27476,7 +28779,7 @@ convertible to T* pointer.
 
    
 
 
    
-Change 20.8.9.2.4 [unique.ptr.single.observers]:
+Change 20.8.14.2.4 [unique.ptr.single.observers]:
 
    
 
 
    
@@ -27486,7 +28789,7 @@ Change 20.8.9.2.4 [unique.ptr.single.observers]:
 
    
 
 
    
-Change 20.8.9.2.5 [unique.ptr.single.modifiers]:
+Change 20.8.14.2.5 [unique.ptr.single.modifiers]:
 
    
 
 
    
@@ -27496,7 +28799,7 @@ Change 20.8.9.2.5 [unique.ptr.single.modifiers]:
 
    
 
 
    
-Change 20.8.9.3 [unique.ptr.runtime]:
+Change 20.8.14.3 [unique.ptr.runtime]:
 
    
 
 
    template <class T, class D> class unique_ptr<T[], D> {
@@ -27516,7 +28819,7 @@ public:
 
    
 
 
    
-Change 20.8.9.3.1 [unique.ptr.runtime.ctor]:
+Change 20.8.14.3.1 [unique.ptr.runtime.ctor]:
 
    
 
 
    
@@ -27535,7 +28838,7 @@ these members. -- end note]
 
    
 
 
    
-Change 20.8.9.3.3 [unique.ptr.runtime.modifiers]:
+Change 20.8.14.3.3 [unique.ptr.runtime.modifiers]:
 
    
 
 
    
@@ -27555,7 +28858,7 @@ templated overload. -- end note]
 
  • 
 
 
    
-Change 20.8.9.2.1 [unique.ptr.single.ctor]:
+Change 20.8.14.2.1 [unique.ptr.single.ctor]:
 
    
 
 
    
@@ -27589,9 +28892,8 @@ required).
 
 
    
 
    674. shared_ptr interface changes for consistency with N1856
    
-
    Section: 20.8.10.2 [util.smartptr.shared] Status: CD1
+
    Section: 20.8.15.2 [util.smartptr.shared] Status: CD1
  Submitter: Peter Dimov Opened: 2007-05-05  Last modified: 2008-09-26
    
-
    View other active issues in [util.smartptr.shared].
    
 
    View all other issues in [util.smartptr.shared].
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
@@ -27605,7 +28907,7 @@ and to interoperate with unique_ptr as it does with auto_ptr.
 
    Proposed resolution:
    
 
 
    
-Change 20.8.10.2 [util.smartptr.shared] as follows:
+Change 20.8.15.2 [util.smartptr.shared] as follows:
 
    
 
 
    
@@ -27619,7 +28921,7 @@ template<class Y, class D> shared_ptr& operator=(unique_ptr<Y,D>
 
    
 
 
    
-Change 20.8.10.2.1 [util.smartptr.shared.const] as follows:
+Change 20.8.15.2.1 [util.smartptr.shared.const] as follows:
 
    
 
 
    
@@ -27627,7 +28929,7 @@ Change 20.8.10.2.1 [util.smartptr.shared.const] as follows:
 
    
 
 
    
-Add to 20.8.10.2.1 [util.smartptr.shared.const]:
+Add to 20.8.15.2.1 [util.smartptr.shared.const]:
 
    
 
 
    
@@ -27648,7 +28950,7 @@ Add to 20.8.10.2.1 [util.smartptr.shared.const]:
 
    
 
 
    
-Change 20.8.10.2.3 [util.smartptr.shared.assign] as follows:
+Change 20.8.15.2.3 [util.smartptr.shared.assign] as follows:
 
    
 
 
    
@@ -27656,7 +28958,7 @@ Change 20.8.10.2.3 [util.smartptr.shared.assign] as follows:
 
    
 
 
    
-Add to 20.8.10.2.3 [util.smartptr.shared.assign]:
+Add to 20.8.15.2.3 [util.smartptr.shared.assign]:
 
    
 
 
    
@@ -28092,14 +29394,15 @@ Change 23.3.6.2 [vector.capacity], p11:
 
 
    
 
    680. move_iterator operator-> return
    
-
    Section: 24.5.2.1 [move.iterator] Status: CD1
+
    Section: 24.5.3.1 [move.iterator] Status: CD1
  Submitter: Howard Hinnant Opened: 2007-06-11  Last modified: 2008-09-26
    
+
    View all other issues in [move.iterator].
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
 
    
 move_iterator's operator-> return type pointer
 does not consistently match the type which is returned in the description
-in 24.5.2.2.5 [move.iter.op.ref].
+in 24.5.3.3.5 [move.iter.op.ref].
 
    
 
 
    template <class Iterator>
@@ -28143,7 +29446,7 @@ finds a non-class type, the second solution avoids the issue of an overloaded
 
 
    Proposed resolution:
    
 
    
-Change the synopsis in 24.5.2.1 [move.iterator]:
+Change the synopsis in 24.5.3.1 [move.iterator]:
 
    
 
 
    typedef typename iterator_traits<Iterator>::pointer pointer;
@@ -28267,7 +29570,7 @@ The LWG voted to accelerate this issue to Ready status to be voted into the WP a
 
 
    
 
    685. reverse_iterator/move_iterator difference has invalid signatures
    
-
    Section: 24.5.1.2.19 [reverse.iter.opdiff], 24.5.2.2.14 [move.iter.nonmember] Status: CD1
+
    Section: 24.5.1.3.19 [reverse.iter.opdiff], 24.5.3.3.14 [move.iter.nonmember] Status: CD1
  Submitter: Bo Persson Opened: 2007-06-10  Last modified: 2008-09-26
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
@@ -28281,7 +29584,7 @@ is possible to compute only if both iterators have the same base
 iterator. The result type is the difference_type of the base iterator. 
 
    
 
    
-In the current draft, the operator is defined as 24.5.1.2.19 [reverse.iter.opdiff] 
+In the current draft, the operator is defined as 24.5.1.3.19 [reverse.iter.opdiff] 
 
    
 
    template<class Iterator1, class Iterator2> 
 typename reverse_iterator<Iterator>::difference_type 
@@ -28299,7 +29602,7 @@ implementation choose one of them? Which one?
 
    
 
    
 The same problem now also appears in operator-() for move_iterator
-24.5.2.2.14 [move.iter.nonmember]. 
+24.5.3.3.14 [move.iter.nonmember]. 
 
    
 
 
@@ -28317,7 +29620,7 @@ Change the synopsis in 24.5.1.1 [reverse.iterator]:
 
    
 
 
    
-Change 24.5.1.2.19 [reverse.iter.opdiff]:
+Change 24.5.1.3.19 [reverse.iter.opdiff]:
 
    
 
 
    
@@ -28335,7 +29638,7 @@ Change 24.5.1.2.19 [reverse.iter.opdiff]:
 
 
 
    
-Change the synopsis in 24.5.2.1 [move.iterator]:
+Change the synopsis in 24.5.3.1 [move.iterator]:
 
    
 
 
    
@@ -28347,7 +29650,7 @@ Change the synopsis in 24.5.2.1 [move.iterator]:
 
    
 
 
    
-Change 24.5.2.2.14 [move.iter.nonmember]:
+Change 24.5.3.3.14 [move.iter.nonmember]:
 
    
 
 
    
@@ -28376,9 +29679,8 @@ goes in.
 
 
    
 
    687. shared_ptr conversion constructor not constrained
    
-
    Section: 20.8.10.2.1 [util.smartptr.shared.const], 20.8.10.3.1 [util.smartptr.weak.const] Status: CD1
+
    Section: 20.8.15.2.1 [util.smartptr.shared.const], 20.8.15.3.1 [util.smartptr.weak.const] Status: CD1
  Submitter: Peter Dimov Opened: 2007-05-10  Last modified: 2009-02-02
    
-
    View other active issues in [util.smartptr.shared.const].
    
 
    View all other issues in [util.smartptr.shared.const].
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
@@ -28406,7 +29708,7 @@ overload resolution when the pointer types are compatible.
 
 
    Proposed resolution:
    
 
    
-In 20.8.10.2.1 [util.smartptr.shared.const], change:
+In 20.8.15.2.1 [util.smartptr.shared.const], change:
 
    
 
 
    
@@ -28417,7 +29719,7 @@ to T*.
 
    
 
 
    
-In 20.8.10.3.1 [util.smartptr.weak.const], change:
+In 20.8.15.3.1 [util.smartptr.weak.const], change:
 
    
 
 
    
@@ -28774,7 +30076,7 @@ Ready.
 
 
    
 
    693. std::bitset::all() missing
    
-
    Section: 20.3.6 [template.bitset] Status: CD1
+
    Section: 20.3.7 [template.bitset] Status: CD1
  Submitter: Martin Sebor Opened: 2007-06-22  Last modified: 2008-09-26
    
 
    View other active issues in [template.bitset].
    
 
    View all other issues in [template.bitset].
    
@@ -28801,7 +30103,7 @@ the first word with a zero bit).
 
    Proposed resolution:
    
 
    
 Add  a declaration of the new  member function all() to the
-defintion of the bitset template in 20.3.6 [template.bitset], p1,
+defintion of the bitset template in 20.3.7 [template.bitset], p1,
 right above the declaration of any() as shown below:
 
    
 
@@ -28813,7 +30115,7 @@ bool none() const;
 
    
 
 
    
-Add a description of the new member function to the end of 20.3.6.2 [bitset.members] with the following text:
+Add a description of the new member function to the end of 20.3.7.2 [bitset.members] with the following text:
 
    
 
    
 bool all() const;
@@ -28854,7 +30156,7 @@ is onecount() == 0.
 
 
    
 
    694. std::bitset and long long
    
-
    Section: 20.3.6 [template.bitset] Status: CD1
+
    Section: 20.3.7 [template.bitset] Status: CD1
  Submitter: Martin Sebor Opened: 2007-06-22  Last modified: 2008-09-26
    
 
    View other active issues in [template.bitset].
    
 
    View all other issues in [template.bitset].
    
@@ -28895,7 +30197,7 @@ explicit bitset(
 
    
 
    
 
    
-Make a corresponding change in 20.3.6.1 [bitset.cons], p2:
+Make a corresponding change in 20.3.7.1 [bitset.cons], p2:
 
    
 
    
 
    
@@ -28918,7 +30220,7 @@ Additionally, introduce a new member function to_ullong()
 to make  it possible to  convert bitset to values  of the
 new  type. Add  the following  declaration  to the  definition of  the
 template, immediate  after the declaration  of to_ulong()
-in 20.3.6 [template.bitset], p1, as shown below:
+in 20.3.7 [template.bitset], p1, as shown below:
 
    
 
    
 
    // element access:
@@ -28931,7 +30233,7 @@ basic_string<charT, traits, Allocator> to_string() const;
 
    
 
    
 
    
-And add a description of  the new member function to 20.3.6.2 [bitset.members],
+And add a description of  the new member function to 20.3.7.2 [bitset.members],
 below  the  description of  the  existing to_ulong()  (if
 possible), with the following text:
 
    
@@ -29013,6 +30315,227 @@ virtual char do_toupper(char c) const;
 
 
 
+
    
+
    696. istream::operator>>(int&) broken
    
+
    Section: 27.7.1.2.2 [istream.formatted.arithmetic] Status: WP
+ Submitter: Martin Sebor Opened: 2007-06-23  Last modified: 2009-10-26
    
+
    View all other issues in [istream.formatted.arithmetic].
    
+
    View all issues with WP status.
    
+
    Discussion:
    
+
    
+From message c++std-lib-17897:
+
    
+
    
+The code shown in 27.7.1.2.2 [istream.formatted.arithmetic] as the "as if"
+implementation of the two arithmetic extractors that don't have a
+corresponding num_get interface (i.e., the
+short and int overloads) is subtly buggy in
+how it deals with EOF, overflow, and other similar
+conditions (in addition to containing a few typos).
+
    
+
    
+One problem is that if num_get::get() reaches the EOF
+after reading in an otherwise valid value that exceeds the limits of
+the narrower type (but not LONG_MIN or
+LONG_MAX), it will set err to
+eofbit. Because of the if condition testing for
+(err == 0), the extractor won't set
+failbit (and presumably, return a bogus value to the
+caller).
+
    
+
    
+Another problem with the code is that it never actually sets the
+argument to the extracted value. It can't happen after the call to
+setstate() since the function may throw, so we need to
+show when and how it's done (we can't just punt as say: "it happens
+afterwards"). However, it turns out that showing how it's done isn't
+quite so easy since the argument is normally left unchanged by the
+facet on error except when the error is due to a misplaced thousands
+separator, which causes failbit to be set but doesn't
+prevent the facet from storing the value.
+
    
+
+
    [
+Batavia (2009-05):
+]
    
+
+
    
+
    
+We believe this part of the Standard has been recently adjusted
+and that this issue was addressed during that rewrite.
+
    
+
    
+Move to NAD.
+
    
+
    
+
+
    [
+2009-05-28 Howard adds:
+]
    
+
+
+
    
+
    
+I've moved this issue from Tentatively NAD to Open.
+
    
+
+
    
+The current wording of
+N2857
+in 22.4.2.1.2 [facet.num.get.virtuals] p3, stage 3 appears to indicate that
+in parsing arithmetic types, the value is always set, but sometimes in addition
+to setting failbit.
+
    
+
+
      
+
    • 
+If there is a range error, the value is set to min or max, else
+
      • 
+
    • 
+if there is a conversion error, the value is set to 0, else
+
      • 
+
    • 
+if there is a grouping error, the value is set to whatever it would be if grouping were ignored, else
+
      • 
+
    • 
+the value is set to its error-free result.
+
      • 
+
    
+
+
    
+However there is a contradictory sentence in 22.4.2.1.2 [facet.num.get.virtuals] p1.
+
    
+
+
    
+27.7.1.2.2 [istream.formatted.arithmetic] should mimic the behavior of 22.4.2.1.2 [facet.num.get.virtuals]
+(whatever we decide that behavior is) for
+int and short, and currently does not.  I believe that the
+correct code fragment should look like:
+
    
+
+
    typedef num_get<charT,istreambuf_iterator<charT,traits> > numget;
+iostate err = ios_base::goodbit;
+long lval;
+use_facet<numget>(loc).get(*this, 0, *this, err, lval);
+if (lval < numeric_limits<int>::min())
+{
+  err |= ios_base::failbit;
+  val = numeric_limits<int>::min();
+}
+else if (lval > numeric_limits<int>::max())
+{
+  err |= ios_base::failbit;
+  val = numeric_limits<int>::max();
+}
+else
+  val = static_cast<int>(lval);
+setstate(err);
+
    
+
    
+
+
    [
+2009-07 Frankfurt
+]
    
+
+
+
    
+Move to Ready.
+
    
+
+
+
+
    Proposed resolution:
    
+
    
+Change 22.4.2.1.2 [facet.num.get.virtuals], p1:
+
    
+
+
    
+-1- Effects: Reads characters from in, interpreting them
+according to str.flags(), use_facet<ctype<charT>
+>(loc), and use_facet< numpunct<charT>
+>(loc), where loc is str.getloc(). If an error
+occurs, val is unchanged; otherwise it is set to the resulting value.
+
    
+
+
    
+Change 27.7.1.2.2 [istream.formatted.arithmetic], p2 and p3:
+
    
+
+
    
+
    operator>>(short& val);
+
    
+
    
+
    
+-2- The conversion occurs as if performed by the following code fragment (using the same notation as for 
+the preceding code fragment):
+
    
+
+
    typedef num_get<charT,istreambuf_iterator<charT,traits> > numget;
+iostate err = iostate_base::goodbit;
+long lval;
+use_facet<numget>(loc).get(*this, 0, *this, err, lval);
+if (err != 0)
+  ;
+else if (lval < numeric_limits<short>::min()
+  || numeric_limits<short>::max() < lval)
+     err = ios_base::failbit;
+if (lval < numeric_limits<short>::min())
+{
+  err |= ios_base::failbit;
+  val = numeric_limits<short>::min();
+}
+else if (lval > numeric_limits<short>::max())
+{
+  err |= ios_base::failbit;
+  val = numeric_limits<short>::max();
+}
+else
+  val = static_cast<short>(lval);
+setstate(err);
+
    
+
+
    
+
+
    operator>>(int& val);
+
    
+
    
+
    
+-3- The conversion occurs as if performed by the following code fragment (using the same notation as for 
+the preceding code fragment):
+
    
+
+
    typedef num_get<charT,istreambuf_iterator<charT,traits> > numget;
+iostate err = iostate_base::goodbit;
+long lval;
+use_facet<numget>(loc).get(*this, 0, *this, err, lval);
+if (err != 0)
+  ;
+else if (lval < numeric_limits<int>::min()
+  || numeric_limits<int>::max() < lval)
+     err = ios_base::failbit;
+if (lval < numeric_limits<int>::min())
+{
+  err |= ios_base::failbit;
+  val = numeric_limits<int>::min();
+}
+else if (lval > numeric_limits<int>::max())
+{
+  err |= ios_base::failbit;
+  val = numeric_limits<int>::max();
+}
+else
+  val = static_cast<int>(lval);
+setstate(err);
+
    
+
+
    
+
+
    
+
+
+
+
+
 
    
 
    698. system_error needs const char* constructors
    
 
    Section: 19.5.5.1 [syserr.syserr.overview] Status: CD1
@@ -29132,9 +30655,8 @@ The LWG voted to accelerate this issue to Ready status to be voted into the WP a
 
 
    
 
    700. N1856 defines struct identity
    
-
    Section: 20.3.2 [forward] Status: CD1
+
    Section: 20.3.3 [forward] Status: CD1
  Submitter: P.J. Plauger Opened: 2007-07-01  Last modified: 2008-09-26
    
-
    View other active issues in [forward].
    
 
    View all other issues in [forward].
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
@@ -29149,7 +30671,7 @@ if we could avoid this name clash for backward compatibility.
 
 
    Proposed resolution:
    
 
    
-Change 20.3.2 [forward]:
+Change 20.3.3 [forward]:
 
    
 
 
    
@@ -29206,7 +30728,6 @@ Add the following to the specification of map::at(), 23.4.1.2 [map.acce
 
    705. type-trait decay incompletely specified
    
 
    Section: 20.6.7 [meta.trans.other] Status: CD1
  Submitter: Thorsten Ottosen Opened: 2007-07-08  Last modified: 2008-09-26
    
-
    View other active issues in [meta.trans.other].
    
 
    View all other issues in [meta.trans.other].
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
@@ -29233,7 +30754,7 @@ Otherwise the  member typedef type equals remove_cv<U
 
    
 
 
    
-In 20.5.2.2 [tuple.creation]/1 change:
+In 20.5.2.4 [tuple.creation]/1 change:
 
    
 
 
    
@@ -29256,15 +30777,15 @@ is X& if Ui equals
 
 
    
 
    706. make_pair() should behave as make_tuple() wrt. reference_wrapper()
    
-
    Section: 20.3.3 [pairs] Status: CD1
+
    Section: 20.3.4 [pairs] Status: CD1
  Submitter: Thorsten Ottosen Opened: 2007-07-08  Last modified: 2008-09-26
    
 
    View other active issues in [pairs].
    
 
    View all other issues in [pairs].
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
 
    
-The current draft has make_pair() in 20.3.3 [pairs]/16
-and make_tuple() in 20.5.2.2 [tuple.creation].
+The current draft has make_pair() in 20.3.4 [pairs]/16
+and make_tuple() in 20.5.2.4 [tuple.creation].
 make_tuple() detects the presence of
 reference_wrapper<X> arguments and "unwraps" the reference in
 such cases. make_pair() would OTOH create a
@@ -29284,8 +30805,8 @@ In 20.3 [utility] change the synopsis for make_pair() to read
 
    • 
 
 
    
-In 20.3.3 [pairs]/16 change the declaration to match the above synopsis.
-Then change the 20.3.3 [pairs]/17 to:
+In 20.3.4 [pairs]/16 change the declaration to match the above synopsis.
+Then change the 20.3.4 [pairs]/17 to:
 
    
 
 
    
@@ -29372,9 +30893,8 @@ Moved from Pending NAD Editorial to Review.  The proposed wording appears to be
 
 
    
 
    710. Missing postconditions
    
-
    Section: 20.8.10.2 [util.smartptr.shared] Status: CD1
+
    Section: 20.8.15.2 [util.smartptr.shared] Status: CD1
  Submitter: Peter Dimov Opened: 2007-08-24  Last modified: 2008-09-26
    
-
    View other active issues in [util.smartptr.shared].
    
 
    View all other issues in [util.smartptr.shared].
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
@@ -29406,7 +30926,7 @@ editor should consider rewording "If w is the return value...", e. g. as
 
 
    Proposed resolution:
    
 
    
-Add to 20.8.10.2.1 [util.smartptr.shared.const]:
+Add to 20.8.15.2.1 [util.smartptr.shared.const]:
 
    
 
 
    
@@ -29422,7 +30942,7 @@ shall be empty. r.get() == 0.
 
    
 
 
    
-Add to 20.8.10.2.10 [util.smartptr.shared.cast]:
+Add to 20.8.15.2.10 [util.smartptr.shared.cast]:
 
    
 
 
    
@@ -29465,7 +30985,7 @@ the aliasing constructor as follows:
 
    
 
 
    
-Change 20.8.10.2.10 [util.smartptr.shared.cast]:
+Change 20.8.15.2.10 [util.smartptr.shared.cast]:
 
    
 
 
    
@@ -29510,6 +31030,149 @@ in the aliasing constructor postcondition "by reference".
 
 
 
+
    
+
    711. Contradiction in empty shared_ptr
    
+
    Section: 20.8.15.2.5 [util.smartptr.shared.obs] Status: WP
+ Submitter: Peter Dimov Opened: 2007-08-24  Last modified: 2009-10-26
    
+
    View all other issues in [util.smartptr.shared.obs].
    
+
    View all issues with WP status.
    
+
    Discussion:
    
+
    
+A discussion on
+comp.std.c++
+has identified a contradiction in the shared_ptr specification.
+The note:
+
    
+
+
    
+[ Note: this constructor allows creation of an empty shared_ptr instance with a non-NULL stored pointer.
+-end note ]
+
    
+
+
    
+after the aliasing constructor
+
    
+
+
    template<class Y> shared_ptr(shared_ptr<Y> const& r, T *p);
+
    
+
+
    
+reflects the intent of
+N2351
+to, well, allow the creation of an empty shared_ptr
+with a non-NULL stored pointer.
+
    
+
+
    
+This is contradicted by the second sentence in the Returns clause of 20.8.15.2.5 [util.smartptr.shared.obs]:
+
    
+
+
    
+
    T* get() const;
+
    
+
    
+Returns: the stored pointer. Returns a null pointer if *this is empty.
+
    
+
    
+
+
    [
+Bellevue:
+]
    
+
+
+
    
+
    
+Adopt option 1 and move to review, not ready.
+
    
+
    
+There was a lot of confusion about what an empty shared_ptr is (the term
+isn't defined anywhere), and whether we have a good mental model for how
+one behaves. We think it might be possible to deduce what the definition
+should be, but the words just aren't there. We need to open an issue on
+the use of this undefined term. (The resolution of that issue might
+affect the resolution of issue 711.)
+
    
+
    
+The LWG is getting more uncomfortable with the aliasing proposal (N2351)
+now that we realize some of its implications, and we need to keep an eye
+on it, but there isn't support for removing this feature at this time.
+
    
+
    
+
+
    [
+Sophia Antipolis:
+]
    
+
+
+
    
+
    
+We heard from Peter Dimov, who explained his reason for preferring solution 1.
+
    
+
    
+Because it doesn't seem to add anything. It simply makes the behavior
+for p = 0 undefined. For programmers who don't create empty pointers
+with p = 0, there is no difference. Those who do insist on creating them
+presumably have a good reason, and it costs nothing for us to define the
+behavior in this case.
+
    
+
    
+The aliasing constructor is sharp enough as it is, so "protecting" users
+doesn't make much sense in this particular case.
+
    
+
    
+> Do you have a use case for r being empty and r being non-null? 
+
    
+
    
+I have received a few requests for it from "performance-conscious"
+people (you should be familiar with this mindset) who don't like the
+overhead of allocating and maintaining a control block when a null
+deleter is used to approximate a raw pointer. It is obviously an "at
+your own risk", low-level feature; essentially a raw pointer behind a
+shared_ptr facade.
+
    
+
    
+We could not agree upon a resolution to the issue; some of us thought
+that Peter's description above is supporting an undesirable behavior.
+
    
+
    
+
+
    [
+2009-07 Frankfurt:
+]
    
+
+
+
    
+
    
+We favor option 1, move to Ready.
+
    
+
    [
+Howard:  Option 2 commented out for clarity, and can be brought back.
+]
    
+
+
    
+
+
+
+
    Proposed resolution:
    
+
    
+In keeping the N2351 spirit and obviously my preference, change 20.8.15.2.5 [util.smartptr.shared.obs]:
+
    
+
+
    
+
    T* get() const;
+
    
+
    
+Returns: the stored pointer. Returns a null pointer if *this is empty.
+
    
+
    
+
+
+
+
+
+
+
+
 
    
 
    712. seed_seq::size no longer useful
    
 
    Section: 26.5.7.1 [rand.util.seedseq] Status: CD1
@@ -29555,7 +31218,7 @@ The LWG voted to accelerate this issue to Ready status to be voted into the WP a
 
 
    
 
    713. sort() complexity is too lax
    
-
    Section: 25.5.1.1 [sort] Status: CD1
+
    Section: 25.4.1.1 [sort] Status: CD1
  Submitter: Matt Austern Opened: 2007-08-30  Last modified: 2008-09-26
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
@@ -29577,7 +31240,7 @@ is no reason not to guarantee it in the standard.
 
 
    Proposed resolution:
    
 
    
-In 25.5.1.1 [sort], change the complexity to "O(N log N)", and remove footnote 266:
+In 25.4.1.1 [sort], change the complexity to "O(N log N)", and remove footnote 266:
 
    
 
 
    
@@ -29599,13 +31262,13 @@ If the worst case behavior is important stable_sort() (25.3.1.2) or 
 
    714. search_n complexity is too lax
    
-
    Section: 25.3.12 [alg.search] Status: CD1
+
    Section: 25.2.12 [alg.search] Status: CD1
  Submitter: Matt Austern Opened: 2007-08-30  Last modified: 2008-09-26
    
 
    View all other issues in [alg.search].
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
 
    
-The complexity for search_n (25.3.12 [alg.search] par 7) is specified as "At most
+The complexity for search_n (25.2.12 [alg.search] par 7) is specified as "At most
 (last - first ) * count applications of the corresponding predicate if
 count is positive, or 0 otherwise." This is unnecessarily pessimistic.
 Regardless of the value of count, there is no reason to examine any
@@ -29645,13 +31308,13 @@ template<class ForwardIterator, class Size, class T,
 
 
    
 
    715. minmax_element complexity is too lax
    
-
    Section: 25.5.7 [alg.min.max] Status: CD1
+
    Section: 25.4.7 [alg.min.max] Status: CD1
  Submitter: Matt Austern Opened: 2007-08-30  Last modified: 2008-09-26
    
 
    View all other issues in [alg.min.max].
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
 
    
-The complexity for minmax_element (25.5.7 [alg.min.max] par 16) says "At most max(2 *
+The complexity for minmax_element (25.4.7 [alg.min.max] par 16) says "At most max(2 *
 (last - first ) - 2, 0) applications of the corresponding comparisons",
 i.e. the worst case complexity is no better than calling min_element and
 max_element separately. This is gratuitously inefficient. There is a
@@ -29662,7 +31325,7 @@ well known technique that does better: see section 9.1 of CLRS
 
 
    Proposed resolution:
    
 
    
-Change 25.5.7 [alg.min.max] to:
+Change 25.4.7 [alg.min.max] to:
 
    
 
 
    
@@ -29696,11 +31359,82 @@ corresponding comparisons predicate, where N is dis
 
 
 
+
    
+
    716. Production in [re.grammar] not actually modified
    
+
    Section: 28.13 [re.grammar] Status: WP
+ Submitter: Stephan T. Lavavej Opened: 2007-08-31  Last modified: 2009-10-26
    
+
    View all issues with WP status.
    
+
    Discussion:
    
+
    
+TR1 7.13 [tr.re.grammar]/3 and C++0x WP 28.13 [re.grammar]/3 say:
+
    
+
+
    
+
    
+The following productions within the ECMAScript grammar are modified as follows:
+
    
+
+
    CharacterClass ::
+[ [lookahead ∉ {^}] ClassRanges ]
+[ ^ ClassRanges ]
+
    
+
+
    
+
+
    
+This definition for CharacterClass appears to be exactly identical to that in ECMA-262.
+
    
+
+
    
+Was an actual modification intended here and accidentally omitted, or was this production accidentally included?
+
    
+
+
    [
+Batavia (2009-05):
+]
    
+
+
    
+
    
+We agree that what is specified is identical to what ECMA-262 specifies.
+Pete would like to take a bit of time to assess whether we had intended,
+but failed, to make a change.
+It would also be useful to hear from John Maddock on the issue.
+
    
+
    
+Move to Open.
+
    
+
    
+
+
    [
+2009-07 Frankfurt:
+]
    
+
+
+
    
+Move to Ready.
+
    
+
+
+
+
    Proposed resolution:
    
+
    
+Remove this mention of the CharacterClass production.
+
    
+
+
    CharacterClass ::
+[ [lookahead ∉ {^}] ClassRanges ]
+[ ^ ClassRanges ]
+
    
+
+
+
+
+
+
 
    
 
    720. Omissions in constexpr usages
    
-
    Section: 23.3.1 [array], 20.3.6 [template.bitset] Status: CD1
+
    Section: 23.3.1 [array], 20.3.7 [template.bitset] Status: CD1
  Submitter: Daniel Krügler Opened: 2007-08-25  Last modified: 2008-09-26
    
-
    View other active issues in [array].
    
 
    View all other issues in [array].
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
@@ -29761,12 +31495,12 @@ In order to have a consistent working paper, Alisdair and Daniel produced a new
 
    • 
 
 
  • 
-
    In the class template definition of 20.3.6 [template.bitset]/p. 1 change
    
+
    In the class template definition of 20.3.7 [template.bitset]/p. 1 change
    
 
    constexpr bool test(size_t pos ) const;
 
    
 
 
    
-and in 20.3.6.2 [bitset.members] change
+and in 20.3.7.2 [bitset.members] change
 
    
 
 
    constexpr bool test(size_t pos ) const;
@@ -29811,6 +31545,145 @@ just after the existing entry nan.
 
 
 
+
    
+
    723. basic_regex should be moveable
    
+
    Section: 28.8 [re.regex] Status: WP
+ Submitter: Daniel Krügler Opened: 2007-08-29  Last modified: 2009-10-26
    
+
    View all other issues in [re.regex].
    
+
    View all issues with WP status.
    
+
    Discussion:
    
+
+
    Addresses UK 316
    
+
+
    
+According to the current state of the standard draft, the class
+template basic_regex, as described in 28.8 [re.regex]/3, is
+neither MoveConstructible nor MoveAssignable.
+IMO it should be, because typical regex state machines tend
+to have a rather large data quantum and I have seen several
+use cases, where a factory function returns regex values,
+which would take advantage of moveabilities.
+
    
+
+
    [
+Sophia Antipolis:
+]
    
+
+
+
    
+Needs wording for the semantics, the idea is agreed upon.
+
    
+
+
    [
+Post Summit Daniel updated wording to reflect new "swap rules".
+]
    
+
+
+
    [
+2009-07 Frankfurt:
+]
    
+
+
+
    
+Move to Ready.
+
    
+
+
+
+
    Proposed resolution:
    
+
    
+In the class definition of basic_regex, just below 28.8 [re.regex]/3,
+perform the following changes:
+
    
+
+
      
+
    1. 
+
      
+Just after basic_regex(const basic_regex&); insert:
+
      
+
+
      basic_regex(basic_regex&&);
+
      
+
      2. 
+
    2. 
+
      
+Just after basic_regex& operator=(const basic_regex&); insert:
+
      
+
      basic_regex& operator=(basic_regex&&);
+
      
+
      3. 
+
    3. 
+
      
+Just after basic_regex& assign(const basic_regex& that); insert:
+
      
+
      basic_regex& assign(basic_regex&& that);
+
      
+
      4. 
+
    4. 
+
      
+In 28.8.2 [re.regex.construct], just after p.11 add the following
+new member definition:
+
      
+
      basic_regex(basic_regex&& e);
+
      
+
      
+
      
+Effects: Move-constructs a basic_regex instance from e.
+
      
+
      
+Postconditions: flags() and mark_count() return e.flags() and
+e.mark_count(), respectively,
+that e had before construction, leaving
+e in a valid state with an unspecified value.
+
      
+
      
+Throws: nothing.
+
      
+
      
+
      
+
      5. 
+
    5. 
+
      
+Also in 28.8.2 [re.regex.construct], just after p.18 add the
+following new member definition:
+
      
+
+
      basic_regex& operator=(basic_regex&& e);
+
      
+
      
+Effects: Returns the result of assign(std::move(e)).
+
      
+
      
+
      6. 
+
    6. 
+
      
+In 28.8.3 [re.regex.assign], just after p. 2 add the following new
+member definition:
+
      
+
      basic_regex& assign(basic_regex&& rhs);
+
      
+
      
+
      
+Effects: Move-assigns a basic_regex instance from rhs and returns *this.
+
      
+
      
+Postconditions: flags() and mark_count() return rhs.flags()
+and rhs.mark_count(), respectively, that
+rhs had before assignment, leaving rhs
+in a valid state with an unspecified value.
+
      
+
      
+Throws: nothing.
+
      
+
      
+
      
+
      7. 
+
    
+
+
+
+
+
 
    
 
    728. Problem in [rand.eng.mers]/6
    
 
    Section: 26.5.3.2 [rand.eng.mers] Status: CD1
@@ -30120,7 +31993,7 @@ straw poll unanimous move to Ready.
 
 
    Proposed resolution:
    
 
    
-Change the synopsis under 20.8.9 [unique.ptr] p2:
+Change the synopsis under 20.8.14 [unique.ptr] p2:
 
    
 
 
    ...
@@ -30151,7 +32024,7 @@ and its subsections:  [unique.ptr.compiletime.dtor],  [unique.ptr.compiletime.ob
 
 
    
 
    743. rvalue swap for shared_ptr
    
-
    Section: 20.8.10.2.9 [util.smartptr.shared.spec] Status: CD1
+
    Section: 20.8.15.2.9 [util.smartptr.shared.spec] Status: CD1
  Submitter: Howard Hinnant Opened: 2007-10-10  Last modified: 2008-09-26
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
@@ -30193,7 +32066,7 @@ Adopt issue as written.
 
 
    Proposed resolution:
    
 
    
-Change the synopsis in 20.8.10.2 [util.smartptr.shared]:
+Change the synopsis in 20.8.15.2 [util.smartptr.shared]:
 
    
 
 
    void swap(shared_ptr&& r);
@@ -30204,14 +32077,14 @@ template<class T> void swap(shared_ptr<T>& a, shared_ptr<T>
 
    
 
 
    
-Change 20.8.10.2.4 [util.smartptr.shared.mod]:
+Change 20.8.15.2.4 [util.smartptr.shared.mod]:
 
    
 
 
    void swap(shared_ptr&& r);
 
    
 
 
    
-Change 20.8.10.2.9 [util.smartptr.shared.spec]:
+Change 20.8.15.2.9 [util.smartptr.shared.spec]:
 
    
 
 
    template<class T> void swap(shared_ptr<T>& a, shared_ptr<T>& b);
@@ -30350,7 +32223,7 @@ Accept the broad view and move to ready
 
 
    Proposed resolution:
    
 
    
-Add the following exemption clause to 17.6.4.10 [res.on.exception.handling]:
+Add the following exemption clause to 17.6.4.11 [res.on.exception.handling]:
 
    
 
 
    
@@ -30436,14 +32309,13 @@ throw any exceptions or T is an array of such a class type.
 
 
    
 
    752. Allocator complexity requirement
    
-
    Section: X [allocator.requirements] Status: WP
+
    Section: 20.2.2 [allocator.requirements] Status: WP
  Submitter: Hans Boehm Opened: 2007-10-11  Last modified: 2009-03-09
    
-
    View other active issues in [allocator.requirements].
    
 
    View all other issues in [allocator.requirements].
    
 
    View all issues with WP status.
    
 
    Discussion:
    
 
    
-Did LWG recently discuss X [allocator.requirements]-2, which states that "All the operations
+Did LWG recently discuss 20.2.2 [allocator.requirements]-2, which states that "All the operations
 on the allocators are expected to be amortized constant time."?
 
    
 
    
@@ -30466,7 +32338,7 @@ the constants, not the asymptotic complexity.
 
 
    Proposed resolution:
    
 
    
-Change X [allocator.requirements]/2:
+Change 20.2.2 [allocator.requirements]/2:
 
    
 
 
    
@@ -30484,7 +32356,7 @@ requirements on allocator types.
 
 
    
 
    753. Move constructor in draft
    
-
    Section: X [utility.arg.requirements] Status: WP
+
    Section: 20.2.1 [utility.arg.requirements] Status: WP
  Submitter: Yechezkel Mett Opened: 2007-10-14  Last modified: 2009-03-09
    
 
    View other active issues in [utility.arg.requirements].
    
 
    View all other issues in [utility.arg.requirements].
    
@@ -30496,7 +32368,7 @@ places, but doesn't seem to define it.
 
    
 
 
    
-MoveConstructible requirements are defined in Table 33 in X [utility.arg.requirements] as
+MoveConstructible requirements are defined in Table 33 in 20.2.1 [utility.arg.requirements] as
 follows:
 
    
 
@@ -30704,9 +32576,8 @@ allow latitude for implementation-specific optimizations.
 
 
    
 
    758. shared_ptr and nullptr
    
-
    Section: 20.8.10.2 [util.smartptr.shared] Status: WP
+
    Section: 20.8.15.2 [util.smartptr.shared] Status: WP
  Submitter: Joe Gottman Opened: 2007-10-31  Last modified: 2009-03-09
    
-
    View other active issues in [util.smartptr.shared].
    
 
    View all other issues in [util.smartptr.shared].
    
 
    View all issues with WP status.
    
 
    Discussion:
    
@@ -30803,7 +32674,7 @@ The following wording changes are less intrusive:
 
    
 
 
    
-In 20.8.10.2.1 [util.smartptr.shared.const], add:
+In 20.8.15.2.1 [util.smartptr.shared.const], add:
 
    
 
 
    shared_ptr(nullptr_t);
@@ -30882,7 +32753,7 @@ Disposition: move to review. The review should check the wording in the then-cur
 
 
    Proposed resolution:
    
 
    
-In 20.8.10.2 [util.smartptr.shared] p4, add to the definition/synopsis
+In 20.8.15.2 [util.smartptr.shared] p4, add to the definition/synopsis
 of shared_ptr:
 
    
 
@@ -30899,7 +32770,7 @@ template<class Y, class D, class A> shared_ptr(Y* p, D d, A a);
 
    
 
 
    
-In 20.8.10.2.1 [util.smartptr.shared.const] add:
+In 20.8.15.2.1 [util.smartptr.shared.const] add:
 
    
 
 
    template<class D> shared_ptr(nullptr_t p, D d);
@@ -30915,11 +32786,11 @@ template<class Y, class D, class A> shared_ptr(Y* p, D d, A a);
 
    
 
 
    
-(reusing the following paragraphs 20.8.10.2.1 [util.smartptr.shared.const]/9-13 that speak of p.)
+(reusing the following paragraphs 20.8.15.2.1 [util.smartptr.shared.const]/9-13 that speak of p.)
 
    
 
 
    
-In 20.8.10.2.1 [util.smartptr.shared.const]/10,  change
+In 20.8.15.2.1 [util.smartptr.shared.const]/10,  change
 
    
 
 
    
@@ -31053,7 +32924,7 @@ Bellevue:  Editorial note: the "(unique)" differs from map.
 
 
    
 
    762. std::unique_ptr requires complete type?
    
-
    Section: 20.8.9 [unique.ptr] Status: CD1
+
    Section: 20.8.14 [unique.ptr] Status: CD1
  Submitter: Daniel Krügler Opened: 2007-11-30  Last modified: 2008-09-26
    
 
    View all other issues in [unique.ptr].
    
 
    View all issues with CD1 status.
    
@@ -31099,7 +32970,7 @@ The specialization unique_ptr<T[]> has some more restrictive cons
 type-completeness on T than unique_ptr<T>. The following proposed wordings
 try to cope with that. If the committee sees less usefulness on relaxed
 constraints on unique_ptr<T[]>, the alternative would be to stop this relaxation
-e.g. by adding one further bullet to 20.8.9.3 [unique.ptr.runtime]/1:
+e.g. by adding one further bullet to 20.8.14.3 [unique.ptr.runtime]/1:
 "T shall be a complete type, if used as template argument of
 unique_ptr<T[], D>
 
    
@@ -31118,7 +32989,7 @@ current specification of unique_ptr.
 
      
 
    1. 
 
      
-In 20.8.9 [unique.ptr]/2 add as the last sentence to the existing para:
+In 20.8.14 [unique.ptr]/2 add as the last sentence to the existing para:
 
      
 
 
      
@@ -31137,7 +33008,7 @@ function. -- end note ]
 
 
    2. 
 
      
-20.8.9.2.1 [unique.ptr.single.ctor]/1: No changes necessary.
+20.8.14.2.1 [unique.ptr.single.ctor]/1: No changes necessary.
 
      
 
 
      
@@ -31151,7 +33022,7 @@ The current wording says just this.
 
 
    3. 
 
      
-In 20.8.9.2.1 [unique.ptr.single.ctor]/5 change the requires clause to say:
+In 20.8.14.2.1 [unique.ptr.single.ctor]/5 change the requires clause to say:
 
      
 
 
      
@@ -31188,7 +33059,7 @@ again requires Completeness of Y, if !SameType<X, Y>
 
 
    4. 
 
      
-Merge 20.8.9.2.1 [unique.ptr.single.ctor]/12+13 thereby removing the sentence
+Merge 20.8.14.2.1 [unique.ptr.single.ctor]/12+13 thereby removing the sentence
 of 12, but transferring the "requires" to 13:
 
      
 
@@ -31207,10 +33078,10 @@ pointer and the D deleter are well-formed and well-defined.
 
      5. 
 
 
    5. 
-20.8.9.2.1 [unique.ptr.single.ctor]/17: No changes necessary.
+20.8.14.2.1 [unique.ptr.single.ctor]/17: No changes necessary.
 
      6. 
 
    6. 
-
      20.8.9.2.1 [unique.ptr.single.ctor]/21:
      
+
      20.8.14.2.1 [unique.ptr.single.ctor]/21:
      
 
 
      
 Requires: If D is not a reference type, construction of
@@ -31233,7 +33104,7 @@ e.g. "U shall be a complete type."
 
 
    7. 
 
      
-20.8.9.2.2 [unique.ptr.single.dtor]: Just before p1 add a new paragraph:
+20.8.14.2.2 [unique.ptr.single.dtor]: Just before p1 add a new paragraph:
 
      
 
      
 
      
@@ -31252,7 +33123,7 @@ type-completeness of T is delegated to this expression.
 
 
    8. 
 
      
-20.8.9.2.3 [unique.ptr.single.asgn]/1: No changes necessary, except the
+20.8.14.2.3 [unique.ptr.single.asgn]/1: No changes necessary, except the
 current editorial issue, that "must shall" has to be changed to
 "shall", but this change is not a special part of this resolution.
 
      
@@ -31266,7 +33137,7 @@ further requirements on the requirements of the effects clause
 
 
    9. 
 
      
-20.8.9.2.3 [unique.ptr.single.asgn]/6:
+20.8.14.2.3 [unique.ptr.single.asgn]/6:
 
      
 
 
      
@@ -31287,7 +33158,7 @@ is true, see (6)+(8).
 
 
    10. 
 
      
-20.8.9.2.3 [unique.ptr.single.asgn]/11: No changes necessary.
+20.8.14.2.3 [unique.ptr.single.asgn]/11: No changes necessary.
 
      
 
      [
 N.B.: Delegation to requirements of effects clause is sufficient.
@@ -31296,7 +33167,7 @@ N.B.: Delegation to requirements of effects clause is sufficient.
 
      11. 
 
 
    11. 
-20.8.9.2.4 [unique.ptr.single.observers]/1+4+7+9+11:
+20.8.14.2.4 [unique.ptr.single.observers]/1+4+7+9+11:
 
      12. 
 
 
      
@@ -31307,12 +33178,12 @@ N.B.: Delegation to requirements of effects clause is sufficient.
 
      
 
 
    12. 
-20.8.9.2.5 [unique.ptr.single.modifiers]/1: No changes necessary.
+20.8.14.2.5 [unique.ptr.single.modifiers]/1: No changes necessary.
 
      13. 
 
 
    13. 
 
      
-20.8.9.2.5 [unique.ptr.single.modifiers]/4: Just before p. 4 add a new paragraph:
+20.8.14.2.5 [unique.ptr.single.modifiers]/4: Just before p. 4 add a new paragraph:
 
      
 
      
 Requires: The expression get_deleter()(get()) shall be well-formed,
@@ -31321,12 +33192,12 @@ shall have well-defined behavior, and shall not throw exceptions.
 
      14. 
 
 
    14. 
-20.8.9.2.5 [unique.ptr.single.modifiers]/7: No changes necessary.
+20.8.14.2.5 [unique.ptr.single.modifiers]/7: No changes necessary.
 
      15. 
 
 
    15. 
 
      
-20.8.9.3 [unique.ptr.runtime]: Add one additional bullet on paragraph 1:
+20.8.14.3 [unique.ptr.runtime]: Add one additional bullet on paragraph 1:
 
      
 
 
      
@@ -31358,9 +33229,8 @@ post Bellevue: Daniel provided revised wording.
 
 
      
 
      765. more on iterator validity
      
-
      Section: 24.2 [iterator.concepts] Status: WP
+
      Section: X [iterator.concepts] Status: WP
  Submitter: Martin Sebor Opened: 2007-12-14  Last modified: 2009-07-18
      
-
      View other active issues in [iterator.concepts].
      
 
      View all other issues in [iterator.concepts].
      
 
      View all issues with WP status.
      
 
      Discussion:
      
@@ -31794,13 +33664,13 @@ Change the synopsis in 29.5.3 [atomics.types.generic]:
 
 
      
 
      769. std::function should use nullptr_t instead of "unspecified-null-pointer-type"
      
-
      Section: 20.7.16.2 [func.wrap.func] Status: CD1
+
      Section: 20.7.15.2 [func.wrap.func] Status: CD1
  Submitter: Daniel Krügler Opened: 2008-01-10  Last modified: 2008-09-26
      
 
      View all other issues in [func.wrap.func].
      
 
      View all issues with CD1 status.
      
 
      Discussion:
      
 
      
-N2461 already replaced in 20.7.16.2 [func.wrap.func] it's originally proposed
+N2461 already replaced in 20.7.15.2 [func.wrap.func] it's originally proposed
 (implicit) conversion operator to "unspecified-bool-type" by the new
 explicit bool conversion, but the inverse conversion should also
 use the new std::nullptr_t type instead of "unspecified-null-pointer-
@@ -31825,7 +33695,7 @@ template<class R, class... ArgTypes>
 
    
 
 
    
-In the class function synopsis of 20.7.16.2 [func.wrap.func] replace
+In the class function synopsis of 20.7.15.2 [func.wrap.func] replace
 
    
 
 
    function(unspecified-null-pointer-type nullptr_t);
@@ -31834,7 +33704,7 @@ function& operator=(unspecified-null-pointer-type nullptr_t<
 
    
 
 
    
-In 20.7.16.2 [func.wrap.func], "Null pointer comparisons" replace:
+In 20.7.15.2 [func.wrap.func], "Null pointer comparisons" replace:
 
    
 
 
    template <class R, class... ArgTypes>
@@ -31848,7 +33718,7 @@ template <class R, class... ArgTypes>
 
    
 
 
    
-In 20.7.16.2.1 [func.wrap.func.con], replace
+In 20.7.15.2.1 [func.wrap.func.con], replace
 
    
 
 
    function(unspecified-null-pointer-type nullptr_t);
@@ -31857,7 +33727,7 @@ function& operator=(unspecified-null-pointer-type nullptr_t<
 
    
 
 
    
-In 20.7.16.2.6 [func.wrap.func.nullptr], replace
+In 20.7.15.2.6 [func.wrap.func.nullptr], replace
 
    
 
 
    template <class R, class... ArgTypes>
@@ -31883,7 +33753,7 @@ template <class R, class... ArgTypes>
 
 
    
 
    770. std::function should use rvalue swap
    
-
    Section: 20.7.16 [func.wrap] Status: CD1
+
    Section: 20.7.15 [func.wrap] Status: CD1
  Submitter: Daniel Krügler Opened: 2008-01-10  Last modified: 2008-09-26
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
@@ -31909,14 +33779,14 @@ template<class R, class... ArgTypes>
 
    
 
 
    
-In 20.7.16.2 [func.wrap.func] class function definition, change
+In 20.7.15.2 [func.wrap.func] class function definition, change
 
    
 
 
    void swap(function&&);
 
    
 
 
    
-In 20.7.16.2 [func.wrap.func], just below of
+In 20.7.15.2 [func.wrap.func], just below of
 
    
 
 
    template <class R, class... ArgTypes>
@@ -31928,14 +33798,14 @@ template <class R, class... ArgTypes>
 
    
 
 
    
-In 20.7.16.2.2 [func.wrap.func.mod] change
+In 20.7.15.2.2 [func.wrap.func.mod] change
 
    
 
 
    void swap(function&& other);
 
    
 
 
    
-In 20.7.16.2.7 [func.wrap.func.alg] add the two overloads
+In 20.7.15.2.7 [func.wrap.func.alg] add the two overloads
 
    
 
 
    template<class R, class... ArgTypes>
@@ -32096,7 +33966,7 @@ character buffer of sufficient size.
 
 
    
 
    775. Tuple indexing should be unsigned?
    
-
    Section: 20.5.2.3 [tuple.helper] Status: CD1
+
    Section: 20.5.2.5 [tuple.helper] Status: CD1
  Submitter: Alisdair Meredith Opened: 2008-01-16  Last modified: 2008-09-26
    
 
    View other active issues in [tuple.helper].
    
 
    View all other issues in [tuple.helper].
    
@@ -32152,7 +34022,7 @@ template<intsize_t I, class T1, class T2>
   const Ptypename tuple_element<I, std::pair<T1, T2> >::type & get(const std::pair<T1, T2>&);
 
    
 
    
-Update 20.3.3 [pairs] Pairs
+Update 20.3.4 [pairs] Pairs
 
    
 
    template<intsize_t I, class T1, class T2>
   Ptypename tuple_element<I, std::pair<T1, T2> >::type & get(pair<T1, T2>&);
@@ -32184,7 +34054,7 @@ template <intsize_t I, class ... types>
 
    
 
 
    
-Update 20.5.2.3 [tuple.helper] Tuple helper classes
+Update 20.5.2.5 [tuple.helper] Tuple helper classes
 
    
 
    template <intsize_t I, class... Types>
 class tuple_element<I, tuple<Types...> > {
@@ -32198,7 +34068,7 @@ public:
 2 Type: TI is the type of the Ith element of Types, where indexing is zero-based.
 
    
 
    
-Update 20.5.2.4 [tuple.elem] Element access
+Update 20.5.2.6 [tuple.elem] Element access
 
    
 
    template <intsize_t I, class... types >
 typename tuple_element<I, tuple<Types...> >::type& get(tuple<Types...>& t);
@@ -32286,7 +34156,6 @@ for pair is also unnecessary.
 
    776. Undescribed assign function of std::array
    
 
    Section: 23.3.1 [array] Status: CD1
  Submitter: Daniel Krügler Opened: 2008-01-20  Last modified: 2008-09-26
    
-
    View other active issues in [array].
    
 
    View all other issues in [array].
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
@@ -32306,7 +34175,7 @@ be derived by those.
 
 
    
 I found only one reference to this function in the issue list,
-588 where the question is raised:
+588 where the question is raised:
 
    
 
 
    
@@ -32380,7 +34249,6 @@ Set state to Review given substitution of "fill" for "assign".
 
    777. Atomics Library Issue
    
 
    Section: 29.6 [atomics.types.operations] Status: CD1
  Submitter: Lawrence Crowl Opened: 2008-01-21  Last modified: 2008-09-26
    
-
    View other active issues in [atomics.types.operations].
    
 
    View all other issues in [atomics.types.operations].
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
@@ -32453,7 +34321,7 @@ C A::load(memory_order order = memory_order_seq_cst) const volatile;
 
 
    
 
    778. std::bitset does not have any constructor taking a string literal
    
-
    Section: 20.3.6.1 [bitset.cons] Status: CD1
+
    Section: 20.3.7.1 [bitset.cons] Status: CD1
  Submitter: Thorsten Ottosen Opened: 2008-01-24  Last modified: 2008-09-26
    
 
    View all other issues in [bitset.cons].
    
 
    View all issues with CD1 status.
    
@@ -32479,14 +34347,14 @@ to std::bitset.
 
 
    Proposed resolution:
    
 
    
-Add to synopsis in 20.3.6 [template.bitset]
+Add to synopsis in 20.3.7 [template.bitset]
 
    
 
 
    explicit bitset( const char* str );
 
    
 
 
    
-Add to synopsis in 20.3.6.1 [bitset.cons]
+Add to synopsis in 20.3.7.1 [bitset.cons]
 
    
 
 
    explicit bitset( const char* str );
@@ -32503,7 +34371,7 @@ Add to synopsis in 20.3.6.1 [bitset.cons]
 
 
    
 
    779. Resolution of #283 incomplete
    
-
    Section: 25.4.8 [alg.remove] Status: CD1
+
    Section: 25.3.8 [alg.remove] Status: CD1
  Submitter: Daniel Krügler Opened: 2008-01-25  Last modified: 2008-09-26
    
 
    View all other issues in [alg.remove].
    
 
    View all issues with CD1 status.
    
@@ -32517,7 +34385,7 @@ which seems to be an oversight.
 
 
    Proposed resolution:
    
 
    
-In 25.4.8 [alg.remove]/p.6, replace the N2461 requires clause with:
+In 25.3.8 [alg.remove]/p.6, replace the N2461 requires clause with:
 
    
 
 
    
@@ -32862,12 +34730,12 @@ terminated thread that can no longer be joined.
 
 
    
 
    787. complexity of binary_search
    
-
    Section: 25.5.3.4 [binary.search] Status: CD1
+
    Section: 25.4.3.4 [binary.search] Status: CD1
  Submitter: Daniel Krügler Opened: 2007-09-08  Last modified: 2008-09-26
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
 
    
-In 25.5.3.4 [binary.search]/3 the complexity of binary_search is described as
+In 25.4.3.4 [binary.search]/3 the complexity of binary_search is described as
 
    
 
 
    
@@ -32903,7 +34771,7 @@ cares about it, he'll send an issue to Howard.
 
 
    Proposed resolution:
    
 
    
-Change 25.5.3.4 [binary.search]/3
+Change 25.4.3.4 [binary.search]/3
 
    
 
 
    
@@ -32914,6 +34782,125 @@ Change 25.5.3.4 [binary.search]/3
 
 
 
+
    
+
    788. ambiguity in [istream.iterator]
    
+
    Section: 24.6.1 [istream.iterator] Status: WP
+ Submitter: Martin Sebor Opened: 2008-02-06  Last modified: 2009-10-26
    
+
    View all other issues in [istream.iterator].
    
+
    View all issues with WP status.
    
+
    Discussion:
    
+
+
    Addresses UK 287
    
+
+
    
+
    
+It is not clear what the initial state of an istream_iterator should be. Is
+_value_ initialized by reading the stream, or default/value initialized? If
+it is initialized by reading the stream, what happens if the initialization
+is deferred until first dereference, when ideally the iterator value should
+have been that of an end-of-stream iterator which is not safely
+dereferencable?
+
    
+
+
    
+Recommendation: Specify _value_ is initialized by reading the stream, or
+the iterator takes on the end-of-stream value if the stream is empty.
+
    
+
    
+
+
    
+The description of how an istream_iterator object becomes an
+end-of-stream iterator is a) ambiguous and b) out of date WRT
+issue 468:
+
    
+
+
    
+istream_iterator reads (using operator>>) successive elements from the
+input stream for which it was constructed. After it is constructed, and
+every time ++ is used, the iterator reads and stores a value of T. If
+the end of stream is reached (operator void*() on the stream returns
+false), the iterator becomes equal to the end-of-stream iterator value.
+The constructor with no arguments istream_iterator() always constructs
+an end of stream input iterator object, which is the only legitimate
+iterator to be used for the end condition. The result of operator* on an
+end of stream is not defined. For any other iterator value a const T& is
+returned. The result of operator-> on an end of stream is not defined.
+For any other iterator value a const T* is returned. It is impossible to
+store things into istream iterators. The main peculiarity of the istream
+iterators is the fact that ++ operators are not equality preserving,
+that is, i == j does not guarantee at all that ++i == ++j. Every time ++
+is used a new value is read.
+
    
+
+
    
+istream::operator void*() returns null if istream::fail() is true,
+otherwise non-null. istream::fail() returns true if failbit or
+badbit is set in rdstate(). Reaching the end of stream doesn't
+necessarily imply that failbit or badbit is set (e.g., after
+extracting an int from stringstream("123") the stream object will
+have reached the end of stream but fail() is false and operator
+void*() will return a non-null value).
+
    
+
+
    
+Also I would prefer to be explicit about calling fail() here
+(there is no operator void*() anymore.)
+
    
+
+
    [
+Summit:
+]
    
+
+
+
    
+Moved from Ready to Open for the purposes of using this issue to address NB UK 287.
+Martin to handle.
+
    
+
+
    [
+2009-07 Frankfurt:
+]
    
+
+
+
    
+
    
+This improves the wording.
+
    
+
    
+Move to Ready.
+
    
+
    
+
+
+
+
    Proposed resolution:
    
+
    
+Change 24.6.1 [istream.iterator]/1:
+
    
+
+
    
+istream_iterator reads (using operator>>) successive elements from the
+input stream for which it was constructed. After it is constructed, and
+every time ++ is used, the iterator reads and stores a value of T. If
+the end of stream is reached the iterator fails to read and store a value of T
+(operator void*() fail() on the stream returns
+false true), the iterator becomes equal to the end-of-stream iterator value.
+The constructor with no arguments istream_iterator() always constructs
+an end of stream input iterator object, which is the only legitimate
+iterator to be used for the end condition. The result of operator* on an
+end of stream is not defined. For any other iterator value a const T& is
+returned. The result of operator-> on an end of stream is not defined.
+For any other iterator value a const T* is returned. It is impossible to
+store things into istream iterators. The main peculiarity of the istream
+iterators is the fact that ++ operators are not equality preserving,
+that is, i == j does not guarantee at all that ++i == ++j. Every time ++
+is used a new value is read.
+
    
+
+
+
+
+
 
    
 
    789. xor_combine_engine(result_type) should be explicit
    
 
    Section: X [rand.adapt.xor] Status: CD1
@@ -32980,7 +34967,7 @@ b) If firstB == lastB or the sequence w has the length ze
 
 
    
 
    798. Refactoring of binders lead to interface breakage
    
-
    Section: D.8 [depr.lib.binders] Status: CD1
+
    Section: D.9 [depr.lib.binders] Status: CD1
  Submitter: Daniel Krügler Opened: 2008-02-14  Last modified: 2008-09-26
    
 
    View all other issues in [depr.lib.binders].
    
 
    View all issues with CD1 status.
    
@@ -32988,7 +34975,7 @@ b) If firstB == lastB or the sequence w has the length ze
 
    
 N2521
 and its earlier predecessors have moved the old binders from
-[lib.binders] to D.8 [depr.lib.binders] thereby introducing some renaming
+[lib.binders] to D.9 [depr.lib.binders] thereby introducing some renaming
 of the template parameter names (Operation -> Fn). During this
 renaming process the protected data member op was also renamed to
 fn, which seems as an unnecessary interface breakage to me - even if
@@ -32998,7 +34985,7 @@ this user access point is probably rarely used.
 
 
    Proposed resolution:
    
 
    
-Change D.8.1 [depr.lib.binder.1st]:
+Change D.9.1 [depr.lib.binder.1st]:
 
    
 
 
    
@@ -33030,7 +35017,7 @@ public:
 
    
 
 
    
-Change D.8.3 [depr.lib.binder.2nd]:
+Change D.9.3 [depr.lib.binder.2nd]:
 
    
 
 
    
@@ -33076,8 +35063,8 @@ public:
 
      
 
    1. 
 
      
-19.5.2.2 [syserr.errcode.overview]/1, class error_code and
-19.5.3.2 [syserr.errcondition.overview]/, class error_condition synopses
+19.5.2.1 [syserr.errcode.overview]/1, class error_code and
+19.5.3.1 [syserr.errcondition.overview]/, class error_condition synopses
 declare an expository data member cat_:
 
      
 
      const error_category& cat_; // exposition only
@@ -33092,7 +35079,7 @@ The classes are not (Copy)Assignable, which is probably not the intent.
 
      2. 
 
    2. 
 The post conditions of all modifiers from
-19.5.2.4 [syserr.errcode.modifiers] and 19.5.3.4 [syserr.errcondition.modifiers], resp.,
+19.5.2.3 [syserr.errcode.modifiers] and 19.5.3.3 [syserr.errcondition.modifiers], resp.,
 cannot be fulfilled.
 
      3. 
 
    
@@ -33114,8 +35101,8 @@ type).
 
 
  • 
 The member function message throws clauses (
-19.5.1.2 [syserr.errcat.virtuals]/10, 19.5.2.5 [syserr.errcode.observers]/8, and
-19.5.3.5 [syserr.errcondition.observers]/6) guarantee "throws nothing",
+19.5.1.2 [syserr.errcat.virtuals]/10, 19.5.2.4 [syserr.errcode.observers]/8, and
+19.5.3.4 [syserr.errcondition.observers]/6) guarantee "throws nothing",
 although
 they return a std::string by value, which might throw in out-of-memory
 conditions (see related issue 771).
@@ -33158,7 +35145,7 @@ Resolution of part A:
 
    
 
    
 
    
-Change 19.5.2.2 [syserr.errcode.overview] Class error_code overview synopsis as indicated:
+Change 19.5.2.1 [syserr.errcode.overview] Class error_code overview synopsis as indicated:
 
    
 
 
    private:
@@ -33167,7 +35154,7 @@ Change 19.5.2.2 [syserr.errcode.overview] Class error_code overview synopsis as
 
    
 
 
    
-Change 19.5.2.3 [syserr.errcode.constructors] Class error_code constructors as indicated:
+Change 19.5.2.2 [syserr.errcode.constructors] Class error_code constructors as indicated:
 
    
 
 
    
@@ -33200,7 +35187,7 @@ Change 19.5.2.3 [syserr.errcode.constructors] Class error_code constructors as i
 
    
 
 
    
-Change 19.5.2.4 [syserr.errcode.modifiers] Class error_code modifiers as indicated:
+Change 19.5.2.3 [syserr.errcode.modifiers] Class error_code modifiers as indicated:
 
    
 
 
    
@@ -33217,7 +35204,7 @@ Change 19.5.2.4 [syserr.errcode.modifiers] Class error_code modifiers as indicat
 
    
 
 
    
-Change 19.5.2.5 [syserr.errcode.observers] Class error_code observers as indicated:
+Change 19.5.2.4 [syserr.errcode.observers] Class error_code observers as indicated:
 
    
 
 
    
@@ -33233,7 +35220,7 @@ const error_category& category() const;
 
    
 
 
    
-Change 19.5.3.2 [syserr.errcondition.overview] Class error_condition overview synopsis as indicated:
+Change 19.5.3.1 [syserr.errcondition.overview] Class error_condition overview synopsis as indicated:
 
    
 
 
    private:
@@ -33242,7 +35229,7 @@ Change 19.5.3.2 [syserr.errcondition.overview] Class error_condition overview sy
 
    
 
 
    
-Change 19.5.3.3 [syserr.errcondition.constructors] Class error_condition constructors as indicated:
+Change 19.5.3.2 [syserr.errcondition.constructors] Class error_condition constructors as indicated:
 
    
 
    [
 (If the proposed resolution of issue 805 has already been applied, the
@@ -33281,7 +35268,7 @@ no effect on this resolution.)
 
    
 
 
    
-Change 19.5.3.4 [syserr.errcondition.modifiers] Class error_condition modifiers as indicated:
+Change 19.5.3.3 [syserr.errcondition.modifiers] Class error_condition modifiers as indicated:
 
    
 
 
    
@@ -33297,7 +35284,7 @@ void assign(int val, const error_category& cat);
 
    
 
 
    
-Change 19.5.3.5 [syserr.errcondition.observers] Class error_condition observers as indicated:
+Change 19.5.3.4 [syserr.errcondition.observers] Class error_condition observers as indicated:
 
    
 
 
    
@@ -33338,7 +35325,7 @@ In 19.5.1.2 [syserr.errcat.virtuals], remove the throws clause p. 10.
 
    
 
 
    
-In 19.5.2.5 [syserr.errcode.observers], remove the throws clause p. 8.
+In 19.5.2.4 [syserr.errcode.observers], remove the throws clause p. 8.
 
    
 
 
    
@@ -33355,7 +35342,7 @@ In 19.5.2.5 [syserr.errcode.observers], remove the throws clause p. 8.
 
    
 
 
    
-In 19.5.3.5 [syserr.errcondition.observers], remove the throws clause p. 6.
+In 19.5.3.4 [syserr.errcondition.observers], remove the throws clause p. 6.
 
    
 
 
    
@@ -33489,7 +35476,7 @@ object's name virtual function shall return a pointer to the string
 
    
 
 
    
-Change 19.5.2.6 [syserr.errcode.nonmembers] Class error_code non-member functions as indicated:
+Change 19.5.2.5 [syserr.errcode.nonmembers] Class error_code non-member functions as indicated:
 
    
 
 
    
@@ -33502,7 +35489,7 @@ Change 19.5.2.6 [syserr.errcode.nonmembers] Class error_code non-member
 
    
 
 
    
-Change 19.5.3.6 [syserr.errcondition.nonmembers] Class error_condition non-member functions as indicated:
+Change 19.5.3.5 [syserr.errcondition.nonmembers] Class error_condition non-member functions as indicated:
 
    
 
 
    
@@ -33632,7 +35619,7 @@ intuitive. There are no uses of errc in the current C++ standard.
 
 
    
 
    806. unique_ptr::reset effects incorrect, too permissive
    
-
    Section: 20.8.9.2.5 [unique.ptr.single.modifiers] Status: CD1
+
    Section: 20.8.14.2.5 [unique.ptr.single.modifiers] Status: CD1
  Submitter: Peter Dimov Opened: 2008-03-13  Last modified: 2008-09-26
    
 
    View all other issues in [unique.ptr.single.modifiers].
    
 
    View all issues with CD1 status.
    
@@ -33685,7 +35672,7 @@ scenario, as it definitely doesn't when p and q are separate.
 
    Proposed resolution:
    
 
 
    
-Change 20.8.9.2.5 [unique.ptr.single.modifiers]:
+Change 20.8.14.2.5 [unique.ptr.single.modifiers]:
 
    
 
 
    
@@ -33697,7 +35684,7 @@ Change 20.8.9.2.5 [unique.ptr.single.modifiers]:
 
    
 
 
    
-Change 20.8.9.3.3 [unique.ptr.runtime.modifiers]:
+Change 20.8.14.3.3 [unique.ptr.runtime.modifiers]:
 
    
 
 
    
@@ -33720,7 +35707,6 @@ Change 20.8.9.3.3 [unique.ptr.runtime.modifiers]:
 
    807. tuple construction should not fail unless its element's construction fails
    
 
    Section: 20.5.2.1 [tuple.cnstr] Status: CD1
  Submitter: Howard Hinnant Opened: 2008-03-13  Last modified: 2008-09-26
    
-
    View other active issues in [tuple.cnstr].
    
 
    View all other issues in [tuple.cnstr].
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
@@ -33748,9 +35734,8 @@ or assignment of one of the types in Types throws an exception.
 
 
    
 
    808. [forward] incorrect redundant specification
    
-
    Section: 20.3.2 [forward] Status: CD1
+
    Section: 20.3.3 [forward] Status: CD1
  Submitter: Jens Maurer Opened: 2008-03-13  Last modified: 2008-09-26
    
-
    View other active issues in [forward].
    
 
    View all other issues in [forward].
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
@@ -33788,7 +35773,7 @@ is just wrong and also redundant.
 
 
    Proposed resolution:
    
 
    
-Change 20.3.2 [forward] as indicated:
+Change 20.3.3 [forward] as indicated:
 
    
 
 
    
@@ -33829,7 +35814,7 @@ In both cases, A2 is deduced as double, so 1.414 is forwarded to A<
 
 
    
 
    809. std::swap should be overloaded for array types
    
-
    Section: 25.4.3 [alg.swap] Status: CD1
+
    Section: 25.3.3 [alg.swap] Status: CD1
  Submitter: Niels Dekker Opened: 2008-02-28  Last modified: 2008-09-26
    
 
    View all other issues in [alg.swap].
    
 
    View all issues with CD1 status.
    
@@ -33896,13 +35881,13 @@ Library] Shouldn't std::swap be overloaded for C-style arrays?
 
 
    Proposed resolution:
    
 
    
-Add an extra condition to the definition of Swappable requirements [swappable] in X [utility.arg.requirements]:
+Add an extra condition to the definition of Swappable requirements [swappable] in 20.2.1 [utility.arg.requirements]:
 
    
 
    
 - T is Swappable if T is an array type whose element type is Swappable.
 
    
 
    
-Add the following to 25.4.3 [alg.swap]:
+Add the following to 25.3.3 [alg.swap]:
 
    
 
    
 
    template<class T, size_t N> void swap(T (&a)[N], T (&b)[N]);
@@ -34031,14 +36016,13 @@ In 27.7 [iostream.format], Header <iomanip> synopsis change:
 
 
    
 
    813. "empty" undefined for shared_ptr
    
-
    Section: 20.8.10.2 [util.smartptr.shared] Status: CD1
+
    Section: 20.8.15.2 [util.smartptr.shared] Status: CD1
  Submitter: Matt Austern Opened: 2008-02-26  Last modified: 2008-09-26
    
-
    View other active issues in [util.smartptr.shared].
    
 
    View all other issues in [util.smartptr.shared].
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
 
    
-Several places in 20.8.10.2 [util.smartptr.shared] refer to an "empty" shared_ptr.
+Several places in 20.8.15.2 [util.smartptr.shared] refer to an "empty" shared_ptr.
 However, that term is nowhere defined. The closest thing we have to a
 definition is that the default constructor creates an empty shared_ptr
 and that a copy of a default-constructed shared_ptr is empty. Are any
@@ -34050,7 +36034,7 @@ term or stop using it.
 One reason it's not good enough to leave this term up to the reader's
 intuition is that, in light of
 N2351
-and issue 711, most readers'
+and issue 711, most readers'
 intuitive understanding is likely to be wrong. Intuitively one might
 expect that an empty shared_ptr is one that doesn't store a pointer,
 but, whatever the definition is, that isn't it.
@@ -34160,7 +36144,7 @@ Alisdair's wording is fine.
 
 
    Proposed resolution:
    
 
    
-Append the following sentance to 20.8.10.2 [util.smartptr.shared]
+Append the following sentance to 20.8.15.2 [util.smartptr.shared]
 
    
 
    
 The shared_ptr class template stores a pointer, usually obtained
@@ -34591,7 +36575,7 @@ Pete will make the required editorial tweaks to rectify this.
 
 
    
 
    821. Minor cleanup : unique_ptr
    
-
    Section: 20.8.9.3.3 [unique.ptr.runtime.modifiers] Status: WP
+
    Section: 20.8.14.3.3 [unique.ptr.runtime.modifiers] Status: WP
  Submitter: Alisdair Meredith Opened: 2008-03-30  Last modified: 2009-03-09
    
 
    View all issues with WP status.
    
 
    Discussion:
    
@@ -34620,7 +36604,7 @@ to be a stronger match than the deleted overload. Words...
 
 
    Proposed resolution:
    
 
    
-Add to class template definition in 20.8.9.3 [unique.ptr.runtime]
+Add to class template definition in 20.8.14.3 [unique.ptr.runtime]
 
    
 
 
    
@@ -34634,7 +36618,7 @@ void swap(unique_ptr&& u);
 
    
 
 
    
-Update 20.8.9.3.3 [unique.ptr.runtime.modifiers]
+Update 20.8.14.3.3 [unique.ptr.runtime.modifiers]
 
    
 
 
    
@@ -34663,6 +36647,137 @@ Note this wording incorporates resolutions for 822. Object with explicit copy constructor no longer CopyConstructible
+
    Section: 20.2.1 [utility.arg.requirements] Status: WP
+ Submitter: James Kanze Opened: 2008-04-01  Last modified: 2009-10-26
    
+
    View other active issues in [utility.arg.requirements].
    
+
    View all other issues in [utility.arg.requirements].
    
+
    View all issues with WP status.
    
+
    Discussion:
    
+
    
+I just noticed that the following program is legal in C++03, but
+is forbidden in the current draft:
+
    
+
+
    #include <vector>
+#include <iostream>
+
+class Toto
+{
+public:
+    Toto() {}
+    explicit Toto( Toto const& ) {}
+} ;
+
+int
+main()
+{
+    std::vector< Toto > v( 10 ) ;
+    return 0 ;
+}
+
    
+
+
    
+Is this change intentional?  (And if so, what is the
+justification?  I wouldn't call such code good, but I don't see
+any reason to break it unless we get something else in return.)
+
    
+
+
    [
+San Francisco:
+]
    
+
+
+
    
+The subgroup that looked at this felt this was a good change, but it may
+already be handled by incoming concepts (we're not sure).
+
    
+
+
    [
+Post Summit:
+]
    
+
+
+
    
+
    
+Alisdair: Proposed resolution kinda funky as these tables no longer
+exist. Move from direct init to copy init. Clarify with Doug, recommends
+NAD.
+
    
+
    
+Walter: Suggest NAD via introduction of concepts.
+
    
+
    
+Recommend close as NAD.
+
    
+
    
+
+
    [
+2009-07 Frankfurt:
+]
    
+
+
+
    
+Need to look at again without concepts.
+
    
+
+
    [
+2009-07 Frankfurt:
+]
    
+
+
+
    
+
    
+Move to Ready with original proposed resolution.
+
    
+
    [Howard:  Original proposed resolution restored.]
    
+
+
    
+
+
+
+
    Proposed resolution:
    
+
    
+In 20.2.1 [utility.arg.requirements] change Table 33: MoveConstructible requirements [moveconstructible]:
+
    
+
+
    
+
+
+
+
+
+
+
+
+
+
+
    expressionpost-condition
    T t(rv) = rvt is equivalent to the value of rv before the construction
    ...
    
+
    
+
+
    
+In 20.2.1 [utility.arg.requirements] change Table 34: CopyConstructible requirements [copyconstructible]:
+
    
+
+
    
+
+
+
+
+
+
+
+
+
+
+
    expressionpost-condition
    T t(u) = uthe value of u is unchanged and is equivalent to t
    ...
    
+
    
+
+
+
+
+
 
    
 
    824. rvalue ref issue with basic_string inserter
    
 
    Section: 21.4.8.9 [string.io] Status: CD1
@@ -34820,9 +36935,201 @@ creates a new copy each time it is called.
 
 
 
+
    
+
    838. 
+   can an end-of-stream iterator become a non-end-of-stream one?
+ 
    
+
    Section: 24.6.1 [istream.iterator] Status: WP
+ Submitter: Martin Sebor Opened: 2008-05-17  Last modified: 2009-10-26
    
+
    View all other issues in [istream.iterator].
    
+
    View all issues with WP status.
    
+
    Discussion:
    
+   
    
+
+From message c++std-lib-20003...
+
+   
    
+   
    
+
+The description of istream_iterator in
+24.6.1 [istream.iterator], p1 specifies that objects of the
+class become the end-of-stream (EOS) iterators under the
+following condition (see also issue 788 another problem
+with this paragraph):
+
+   
    
+   
    
+
+If the end of stream is reached (operator void*() on the
+stream returns false), the iterator becomes equal to
+the end-of-stream iterator value.
+
+   
    
+   
    
+
+One possible implementation approach that has been used in practice is
+for the iterator to set its in_stream pointer to 0 when
+it reaches the end of the stream, just like the default ctor does on
+initialization. The problem with this approach is that
+the Effects clause for operator++() says the
+iterator unconditionally extracts the next value from the stream by
+evaluating *in_stream >> value, without checking
+for (in_stream == 0).
+
+   
    
+   
    
+
+Conformance to the requirement outlined in the Effects clause
+can easily be verified in programs by setting eofbit
+or failbit in exceptions() of the associated
+stream and attempting to iterate past the end of the stream: each
+past-the-end access should trigger an exception. This suggests that
+some other, more elaborate technique might be intended.
+
+   
    
+   
    
+
+Another approach, one that allows operator++() to attempt
+to extract the value even for EOS iterators (just as long
+as in_stream is non-0) is for the iterator to maintain a
+flag indicating whether it has reached the end of the stream. This
+technique would satisfy the presumed requirement implied by
+the Effects clause mentioned above, but it isn't supported by
+the exposition-only members of the class (no such flag is shown). This
+approach is also found in existing practice.
+
+   
    
+   
    
+
+The inconsistency between existing implementations raises the question
+of whether the intent of the specification is that a non-EOS iterator
+that has reached the EOS become a non-EOS one again after the
+stream's eofbit flag has been cleared? That is, are the
+assertions in the program below expected to pass?
+
+   
    
+   
    
+     
       sstream strm ("1 ");
+   istream_iterator eos;
+   istream_iterator it (strm);
+   int i;
+   i = *it++
+   assert (it == eos);
+   strm.clear ();
+   strm << "2 3 ";
+   assert (it != eos);
+   i = *++it;
+   assert (3 == i);
+     
    
+   
    
+   
    
+
+Or is it intended that once an iterator becomes EOS it stays EOS until
+the end of its lifetime?
+
+   
    
+ 
+ 
    [
+San Francisco:
+]
    
+
+
+
    
+
    
+We like the direction of the proposed resolution. We're not sure about
+the wording, and we need more time to reflect on it,
+
    
+
    
+Move to Open. Detlef to rewrite the proposed resolution in such a way
+that no reference is made to exposition only members of
+istream_iterator.
+
    
+
    
+
+
    [
+2009-07 Frankfurt:
+]
    
+
+
+
    
+Move to Ready.
+
    
+
+
+
+ 
    Proposed resolution:
    
+   
    
+
+The discussion of this issue on the reflector suggests that the intent
+of the standard is for an istreambuf_iterator that has
+reached the EOS to remain in the EOS state until the end of its
+lifetime. Implementations that permit EOS iterators to return to a
+non-EOS state may only do so as an extension, and only as a result of
+calling istream_iterator member functions on EOS
+iterators whose behavior is in this case undefined.
+
+   
    
+   
    
+
+To this end we propose to change 24.6.1 [istream.iterator], p1,
+as follows:
+
+   
    
+   
    
+
+The result of operator-> on an end-of-stream
+is not defined. For any other iterator value a const T*
+is returned. Invoking operator++() on
+an end-of-stream iterator is undefined. It is impossible
+to store things into istream iterators...
+
+   
    
+   
    
+
+Add pre/postconditions to the member function descriptions of istream_iterator like so:
+
+   
    
+   
    
+
+
    istream_iterator();
    
+
+Effects: Constructs the end-of-stream iterator.
    
+Postcondition: in_stream == 0.
+
+
    istream_iterator(istream_type &s);
    
+
+Effects: Initializes in_stream with &s. value
+may be initialized during construction or the first time it is
+referenced.
    
+Postcondition: in_stream == &s.
+
+
    istream_iterator(const istream_iterator &x);
    
+
+Effects: Constructs a copy of x.
    
+Postcondition: in_stream == x.in_stream.
+
+
    istream_iterator& operator++();
    
+
+Requires: in_stream != 0.
    
+Effects: *in_stream >> value.
+
+
    istream_iterator& operator++(int);
    
+
+Requires: in_stream != 0.
    
+Effects:
+   
    istream_iterator tmp (*this);
+*in_stream >> value;
+return tmp;
+     
    
+     
    
+   
    
+ 
+
+
+
 
    
 
    842. ConstructibleAsElement and bit containers
    
-
    Section: 23.2 [container.requirements], 23.3.7 [vector.bool], 20.3.6 [template.bitset] Status: CD1
+
    Section: 23.2 [container.requirements], 23.3.7 [vector.bool], 20.3.7 [template.bitset] Status: CD1
  Submitter: Howard Hinnant Opened: 2008-06-03  Last modified: 2008-09-26
    
 
    View other active issues in [container.requirements].
    
 
    View all other issues in [container.requirements].
    
@@ -34847,7 +37154,7 @@ with a scoped allocator of type A (i.e., an allocator for which
 
 
    
 However vector<bool, A> (23.3.7 [vector.bool]) and bitset<N> 
-(20.3.6 [template.bitset]) store bits, not bools, and bitset<N>
+(20.3.7 [template.bitset]) store bits, not bools, and bitset<N>
 does not even have an allocator.  But these containers are governed by this clause.  Clearly this
 is not implementable.
 
    
@@ -34883,7 +37190,7 @@ and construct_element (23.2 [container.requirements]) is not used to co
 
    
 
 
    
-Move 20.3.6 [template.bitset] to clause 20.
+Move 20.3.7 [template.bitset] to clause 20.
 
    
 
 
@@ -35243,9 +37550,132 @@ Construction is not atomic.
 
 
 
+
    
+
    847. string exception safety guarantees
    
+
    Section: 21.4.1 [string.require] Status: WP
+ Submitter: Hervé Brönnimann Opened: 2008-06-05  Last modified: 2009-10-26
    
+
    View all other issues in [string.require].
    
+
    View all issues with WP status.
    
+
    Discussion:
    
+
    
+In March, on comp.lang.c++.moderated, I asked what were the
+string exception safety guarantees are, because I cannot see
+*any* in the working paper, and any implementation I know offers
+the strong exception safety guarantee (string unchanged if a
+member throws exception). The closest the current draft comes to
+offering any guarantees is 21.4 [basic.string], para 3:
+
    
+
+
    
+The class template basic_string conforms to the requirements
+for a Sequence Container (23.1.1), for a Reversible Container (23.1),
+and for an Allocator-aware container (91). The iterators supported by
+basic_string are random access iterators (24.1.5).
+
    
+
+
    
+However, the chapter 23 only says, on the topic of exceptions:  23.2 [container.requirements],
+para 10:
+
    
+
+
    
+
    
+Unless otherwise specified (see 23.2.2.3 and 23.2.6.4) all container types defined in this clause meet the following 
+additional requirements:
+
    
+
+
      
+
    • if an exception is thrown by...
      • 
+
    
+
    
+
+
    
+I take it  as saying that this paragraph has *no* implication on
+std::basic_string, as basic_string isn't defined in Clause 23 and
+this paragraph does not define a *requirement* of Sequence
+nor Reversible Container, just of the models defined in Clause 23.
+In addition, LWG Issue 718 proposes to remove 23.2 [container.requirements], para 3.
+
    
+
+
    
+Finally, the fact that no operation on Traits should throw
+exceptions has no bearing, except to suggest (since the only
+other throws should be allocation, out_of_range, or length_error)
+that the strong exception guarantee can be achieved.
+
    
+
+
    
+The reaction in that group by Niels Dekker, Martin Sebor, and
+Bo Persson, was all that this would be worth an LWG issue.
+
    
+
+
    
+A related issue is that erase() does not throw.  This should be
+stated somewhere (and again, I don't think that the 23.2 [container.requirements], para 1
+applies here).
+
    
+
+
    [
+San Francisco:
+]
    
+
+
+
    
+Implementors will study this to confirm that it is actually possible.
+
    
+
+
    [
+Daniel adds 2009-02-14:
+]
    
+
+
+
    
+The proposed resolution of paper
+N2815
+interacts with this issue (the paper does not refer to this issue).
+
    
+
+
    [
+2009-07 Frankfurt:
+]
    
+
+
+
    
+Move to Ready.
+
    
+
+
+
+
    Proposed resolution:
    
+
    
+Add a blanket statement in 21.4.1 [string.require]:
+
    
+
+
    
+
    
+- if any member function or operator of basic_string<charT, traits, Allocator>
+throws, that function or operator has no effect.
+
    
+
    
+- no erase() or pop_back() function throws.
+
    
+
    
+
+
    
+As far as I can tell, this is achieved by any implementation.  If I made a
+mistake and it is not possible to offer this guarantee, then
+either state all the functions for which this is possible
+(certainly at least operator+=, append, assign, and insert),
+or add paragraphs to Effects clauses wherever appropriate.
+
    
+
+
+
+
+
 
    
 
    848. missing std::hash specializations for std::bitset/std::vector<bool>
    
-
    Section: 20.7.17 [unord.hash] Status: CD1
+
    Section: 20.7.16 [unord.hash] Status: CD1
  Submitter: Thorsten Ottosen Opened: 2008-06-05  Last modified: 2008-09-26
    
 
    View other active issues in [unord.hash].
    
 
    View all other issues in [unord.hash].
    
@@ -35271,7 +37701,7 @@ template<size_t N> struct hash<std::bitset<N>>;
 
    
 
 
    
-Modify the last sentence of 20.7.17 [unord.hash]/1 to end with:
+Modify the last sentence of 20.7.16 [unord.hash]/1 to end with:
 
    
 
 
    
@@ -35382,7 +37812,7 @@ Change the synopsis in 23.5.1 [unord.map], 23.5.2 [unord.multimap], and 23.5.4 [
 
 
    
 
    853. to_string needs updating with zero and one
    
-
    Section: 20.3.6 [template.bitset] Status: WP
+
    Section: 20.3.7 [template.bitset] Status: WP
  Submitter: Howard Hinnant Opened: 2008-06-18  Last modified: 2009-07-18
    
 
    View other active issues in [template.bitset].
    
 
    View all other issues in [template.bitset].
    
@@ -35435,7 +37865,7 @@ Recommend Tentatively Ready.
 
    Proposed resolution:
    
 
      
 
    1. 
-
      replace in 20.3.6 [template.bitset]/1 (class bitset)
+
      replace in 20.3.7 [template.bitset]/1 (class bitset)
 
      
 
      template <class charT, class traits>
   basic_string<charT, traits, allocator<charT> >
@@ -35449,7 +37879,7 @@ basic_string<char, char_traits<char>, allocator<char> >
 
      2. 
 
    2. 
 
      
-replace in 20.3.6.2 [bitset.members]/37
+replace in 20.3.7.2 [bitset.members]/37
 
      
 
      template <class charT, class traits>
   basic_string<charT, traits, allocator<charT> >
@@ -35462,7 +37892,7 @@ replace in 20.3.6.2 [bitset.members]/37
 
      3. 
 
    3. 
 
      
-replace in 20.3.6.2 [bitset.members]/38
+replace in 20.3.7.2 [bitset.members]/38
 
      
 
 
      template <class charT>
@@ -35477,7 +37907,7 @@ replace in 20.3.6.2 [bitset.members]/38
 
 
    4. 
 
      
-replace in 20.3.6.2 [bitset.members]/39
+replace in 20.3.7.2 [bitset.members]/39
 
      
 
 
      basic_string<char, char_traits<char>, allocator<char> >
@@ -35500,7 +37930,6 @@ replace in 20.3.6.2 [bitset.members]/39
 
      856. Removal of aligned_union
      
 
      Section: 20.6.7 [meta.trans.other] Status: CD1
  Submitter: Jens Maurer Opened: 2008-06-12  Last modified: 2008-09-26
      
-
      View other active issues in [meta.trans.other].
      
 
      View all other issues in [meta.trans.other].
      
 
      View all issues with CD1 status.
      
 
      Discussion:
      
@@ -35534,9 +37963,389 @@ struct aligned_union;
 
 
 
+
      
+
      857. condition_variable::time_wait return bool error prone
      
+
      Section: 30.5.1 [thread.condition.condvar] Status: WP
+ Submitter: Beman Dawes Opened: 2008-06-13  Last modified: 2009-10-26
      
+
      View other active issues in [thread.condition.condvar].
      
+
      View all other issues in [thread.condition.condvar].
      
+
      View all issues with WP status.
      
+
      Discussion:
      
+
      
+The meaning of the bool returned by condition_variable::timed_wait is so
+obscure that even the class' designer can't deduce it correctly. Several
+people have independently stumbled on this issue.
+
      
+
      
+It might be simpler to change the return type to a scoped enum:
+
      
+
      enum class timeout { not_reached, reached };
+
      
+
+
      
+That's the same cost as returning a bool, but not subject to mistakes. Your example below would be:
+
      
+
+
      if (cv.wait_until(lk, time_limit) == timeout::reached )
+  throw time_out();
+
      
+
+
      [
+Beman to supply exact wording.
+]
      
+
+
+
      [
+San Francisco:
+]
      
+
+
+
      
+
      
+There is concern that the enumeration names are just as confusing, if
+not more so, as the bool. You might have awoken because of a signal or a
+spurious wakeup, for example.
+
      
+
      
+Group feels that this is a defect that needs fixing.
+
      
+
      
+Group prefers returning an enum over a void return.
+
      
+
      
+Howard to provide wording.
+
      
+
      
+
+
      [
+2009-06-14 Beman provided wording.
+]
      
+
+
+
      [
+2009-07 Frankfurt:
+]
      
+
+
+
      
+Move to Ready.
+
      
+
+
+
+
      Proposed resolution:
      
+
      
+Change Condition variables 30.5 [thread.condition], Header
+condition_variable synopsis, as indicated:
+
      
+
+
      namespace std {
+  class condition_variable;
+  class condition_variable_any;
+
+  enum class cv_status { no_timeout, timeout };
+}
+
      
+
+
      
+Change Class condition_variable 30.5.1 [thread.condition.condvar] as indicated:
+
      
+
+
      class condition_variable { 
+public:
+  ...
+  template <class Clock, class Duration>
+    bool cv_status wait_until(unique_lock<mutex>& lock,
+                    const chrono::time_point<Clock, Duration>& abs_time);
+  template <class Clock, class Duration, class Predicate>
+    bool wait_until(unique_lock<mutex>& lock,
+                    const chrono::time_point<Clock, Duration>& abs_time,
+                    Predicate pred);
+
+  template <class Rep, class Period>
+    bool cv_status wait_for(unique_lock<mutex>& lock,
+                  const chrono::duration<Rep, Period>& rel_time);
+  template <class Rep, class Period, class Predicate>
+    bool wait_for(unique_lock<mutex>& lock,
+                  const chrono::duration<Rep, Period>& rel_time,
+                  Predicate pred);
+  ...
+};
+
+...
+
+template <class Clock, class Duration>
+  bool cv_status wait_until(unique_lock<mutex>& lock,
+                  const chrono::time_point<Clock, Duration>& abs_time);
+
      
+
      
+
      
+-15- Precondition: lock is locked by the calling thread, and either
+
      
+
        
+
      • 
+no other thread is waiting on this condition_variable object or
+
        • 
+
      • 
+lock.mutex() returns the same value for each of the lock
+arguments supplied by all concurrently waiting threads (via wait,
+wait_for or wait_until.).
+
        • 
+
      
+
+
      
+-16- Effects:
+
      
+
+
        
+
      • 
+Atomically calls lock.unlock() and blocks on *this.
+
        • 
+
      • 
+When unblocked, calls lock.lock() (possibly blocking on the lock) and returns.
+
        • 
+
      • 
+The function will unblock when signaled by a call to notify_one(),
+a call to notify_all(), by 
+the current time exceeding abs_time if Clock::now() >= abs_time,
+or spuriously.
+
        • 
+
      • 
+If the function exits via an exception, lock.unlock() shall be called prior
+to exiting the function scope.
+
        • 
+
      
+
+
      
+-17- Postcondition: lock is locked by the calling thread.
+
      
+
+
      
+-18- Returns: Clock::now() < abs_time
+cv_status::timeout if the function unblocked because abs_time
+was reached, otherwise cv_status::no_timeout.
+
      
+
+
      
+-19- Throws: std::system_error when the effects or postcondition
+cannot be achieved.
+
      
+
+
      
+-20- Error conditions:
+
      
+
+
        
+
      • 
+operation_not_permitted — if the thread does not own the lock.
+
        • 
+
      • 
+equivalent error condition from lock.lock() or lock.unlock().
+
        • 
+
      
+
      
+
+
      template <class Rep, class Period>
+  bool cv_status wait_for(unique_lock<mutex>& lock,
+                const chrono::duration<Rep, Period>& rel_time);
+
+
      
+
      
+
      
+-21- Effects Returns:
+
      
+
      wait_until(lock, chrono::monotonic_clock::now() + rel_time)
+
      
+
      
+-22- Returns: false if the call is returning because the time
+duration specified by rel_time has elapsed, 
+otherwise true.
+
      
+
+
      [
+This part of the wording may conflict with 859 in detail, but does
+not do so in spirit.  If both issues are accepted, there is a logical merge.
+]
      
+
+
      
+
+
      template <class Clock, class Duration, class Predicate> 
+  bool wait_until(unique_lock<mutex>& lock, 
+                  const chrono::time_point<Clock, Duration>& abs_time, 
+                  Predicate pred);
+
      
+
+
      
+
      
+-23- Effects:
+
      
+
      while (!pred()) 
+  if (!wait_until(lock, abs_time) == cv_status::timeout) 
+    return pred(); 
+return true;
+
      
+
+
      
+-24- Returns: pred().
+
      
+
+
      
+-25- [Note:
+The returned value indicates whether the predicate evaluates to
+true regardless of whether the timeout was triggered.
+— end note].
+
      
+
      
+
      
+
+
      
+Change Class condition_variable_any 30.5.2 [thread.condition.condvarany] as indicated:
+
      
+
+
      class condition_variable_any {
+public:
+  ...
+  template <class Lock, class Clock, class Duration>
+    bool cv_status wait_until(Lock& lock,
+                    const chrono::time_point<Clock, Duration>& abs_time);
+  template <class Lock, class Clock, class Duration, class Predicate>
+    bool wait_until(Lock& lock,
+                    const chrono::time_point<Clock, Duration>& abs_time,
+                    Predicate pred);
+
+  template <class Lock, class Rep, class Period>
+    bool cv_status wait_for(Lock& lock,
+                  const chrono::duration<Rep, Period>& rel_time);
+  template <class Lock, class Rep, class Period, class Predicate>
+    bool wait_for(Lock& lock,
+                  const chrono::duration<Rep, Period>& rel_time,
+                  Predicate pred);
+  ...
+};
+
+...
+
+template <class Lock, class Clock, class Duration>
+  bool cv_status wait_until(Lock& lock,
+                  const chrono::time_point<Clock, Duration>& abs_time);
+
      
+
+
      
+
+
      
+-13- Effects:
+
      
+
+
        
+
      • 
+Atomically calls lock.unlock() and blocks on *this.
+
        • 
+
      • 
+When unblocked, calls lock.lock() (possibly blocking on the lock) and returns.
+
        • 
+
      • 
+The function will unblock when signaled by a call to notify_one(),
+a call to notify_all(), by 
+the current time exceeding abs_time if Clock::now() >= abs_time,
+or spuriously.
+
        • 
+
      • 
+If the function exits via an exception, lock.unlock() shall be called prior
+to exiting the function scope.
+
        • 
+
      
+
+
      
+-14- Postcondition: lock is locked by the calling thread.
+
      
+
+
      
+-15- Returns: Clock::now() < abs_time
+cv_status::timeout if the function unblocked because abs_time
+was reached, otherwise cv_status::no_timeout.
+
      
+
+
      
+-16- Throws: std::system_error when the effects or postcondition
+cannot be achieved.
+
      
+
+
      
+-17- Error conditions:
+
      
+
+
        
+
      • 
+equivalent error condition from lock.lock() or lock.unlock().
+
        • 
+
      
+
      
+
+
      template <class Lock, class Rep, class Period>
+  bool cv_status wait_for(Lock& lock,
+                const chrono::duration<Rep, Period>& rel_time);
+
+
      
+
+
      
+
      
+-18- Effects Returns:
+
      
+
      wait_until(lock, chrono::monotonic_clock::now() + rel_time)
+
      
+
+
      
+-19- Returns: false if the call is returning because the time
+duration specified by rel_time has elapsed, 
+otherwise true.
+
      
+
+
      [
+This part of the wording may conflict with 859 in detail, but does
+not do so in spirit.  If both issues are accepted, there is a logical merge.
+]
      
+
+
+
      
+
+
      template <class Lock, class Clock, class Duration, class Predicate> 
+  bool wait_until(Lock& lock, 
+                  const chrono::time_point<Clock, Duration>& rel_time abs_time, 
+                  Predicate pred);
+
      
+
+
      
+
      
+-20- Effects:
+
      
+
      while (!pred()) 
+  if (!wait_until(lock, abs_time) == cv_status::timeout) 
+    return pred(); 
+return true;
+
      
+
+
      
+-21- Returns: pred().
+
      
+
+
      
+-22- [Note:
+The returned value indicates whether the predicate evaluates to
+true regardless of whether the timeout was triggered.
+— end note].
+
      
+
      
+
+
      
+
+
+
+
+
+
 
      
 
      858. Wording for Minimal Support for Garbage Collection
      
-
      Section: 20.8.10.7 [util.dynamic.safety] Status: CD1
+
      Section: 20.8.15.6 [util.dynamic.safety] Status: CD1
  Submitter: Pete Becker  Opened: 2008-06-21  Last modified: 2008-09-26
      
 
      View all other issues in [util.dynamic.safety].
      
 
      View all issues with CD1 status.
      
@@ -35587,7 +38396,7 @@ to clarify the intent.
 
 
      Proposed resolution:
      
 
      
-In 20.8.10.7 [util.dynamic.safety]
+In 20.8.15.6 [util.dynamic.safety]
 (N2670,
 Minimal Support for Garbage Collection)
 
      
@@ -35656,22 +38465,475 @@ note]
 
 
 
+
      
+
      859. Monotonic Clock is Conditionally Supported?
      
+
      Section: 30.5 [thread.condition] Status: WP
+ Submitter: Pete Becker Opened: 2008-06-23  Last modified: 2009-10-26
      
+
      View other active issues in [thread.condition].
      
+
      View all other issues in [thread.condition].
      
+
      View all issues with WP status.
      
+
      Discussion:
      
+
+
      Related to 958, 959.
      
+
+
      
+N2661
+says that there is a class named monotonic_clock. It also says that this
+name may be a synonym for system_clock, and that it's conditionally
+supported. So the actual requirement is that it can be monotonic or not,
+and you can tell by looking at is_monotonic, or it might not exist at
+all (since it's conditionally supported). Okay, maybe too much
+flexibility, but so be it.
+
      
+
      
+A problem comes up in the threading specification, where several
+variants of wait_for explicitly use monotonic_clock::now(). What is the
+meaning of an effects clause that says
+
      
+
+
      wait_until(lock, chrono::monotonic_clock::now() + rel_time)
+
      
+
+
      
+when monotonic_clock is not required to exist?
+
      
+
+
      [
+San Francisco:
+]
      
+
+
+
      
+
      
+Nick: maybe instead of saying that chrono::monotonic_clock is
+conditionally supported, we could say that it's always there, but not
+necessarily supported..
+
      
+
      
+Beman: I'd prefer a typedef that identifies the best clock to use for
+wait_for locks.
+
      
+
      
+Tom: combine the two concepts; create a duration clock type, but keep
+the is_monotonic test.
+
      
+
      
+Howard: if we create a duration_clock type, is it a typedef or an
+entirely true type?
+
      
+
      
+There was broad preference for a typedef.
+
      
+
      
+Move to Open. Howard to provide wording to add a typedef for
+duration_clock and to replace all uses of monotonic_clock in function
+calls and signatures with duration_clock.
+
      
+
      
+
+
      [
+Howard notes post-San Francisco:
+]
      
+
+
+
      
+
      
+After further thought I do not believe that creating a duration_clock typedef
+is the best way to proceed.  An implementation may not need to use a
+time_point to implement the wait_for functions.
+
      
+
+
      
+For example, on POSIX systems sleep_for can be implemented in terms of
+nanosleep which takes only a duration in terms of nanoseconds.  The current
+working paper does not describe sleep_for in terms of sleep_until.
+And paragraph 2 of 30.2.4 [thread.req.timing] has the words strongly encouraging
+implementations to use monotonic clocks for sleep_for:
+
      
+
+
      
+2 The member functions whose names end in _for take an argument that
+specifies a relative time. Implementations should use a monotonic clock to
+measure time for these functions.
+
      
+
+
      
+I believe the approach taken in describing the effects of sleep_for
+and try_lock_for is also appropriate for wait_for.  I.e. these
+are not described in terms of their _until variants.
+
      
+
+
      
+
+
      [
+2009-07 Frankfurt:
+]
      
+
+
+
      
+
      
+Beman will send some suggested wording changes to Howard.
+
      
+
      
+Move to Ready.
+
      
+
      
+
+
      [
+2009-07-21 Beman added the requested wording changes to 962.
+]
      
+
+
+
+
+
      Proposed resolution:
      
+
      
+Change 30.5.1 [thread.condition.condvar], p21-22:
+
      
+
+
      
+
      template <class Rep, class Period> 
+  bool wait_for(unique_lock<mutex>& lock, 
+                const chrono::duration<Rep, Period>& rel_time);
+
      
+
      
+
      
+Precondition: lock is locked by the calling thread, and either
+
      
+
        
+
      • no other thread is waiting on this condition_variable object or
        • 
+
      • lock.mutex() returns the same value for each of the lock
+arguments supplied by all concurrently waiting threads (via wait,
+wait_for or wait_until).
        • 
+
      
+
      
+21 Effects:
+
      
+
      wait_until(lock, chrono::monotonic_clock::now() + rel_time)
+
      
+
        
+
      • 
+Atomically calls lock.unlock() and blocks on *this.
+
        • 
+
+
      • 
+When unblocked, calls lock.lock() (possibly blocking on the lock) and returns.
+
        • 
+
+
      • 
+The function will unblock when signaled by a call to notify_one(), a call
+to notify_all(), by 
+the elapsed time rel_time passing (30.2.4 [thread.req.timing]),
+or spuriously.
+
        • 
+
+
      • 
+If the function exits via an exception, lock.unlock() shall be called 
+prior to exiting the function scope.
+
        • 
+
      
+
+
      
+Postcondition: lock is locked by the calling thread.
+
      
+
+
+
      
+22 Returns: false if the call is returning because the time
+duration specified by rel_time has elapsed, otherwise true.
+
      
+
+
      [
+This part of the wording may conflict with 857 in detail, but does
+not do so in spirit.  If both issues are accepted, there is a logical merge.
+]
      
+
+
+
      
+Throws: std::system_error when the effects or postcondition cannot be achieved.
+
      
+
+
      
+Error conditions:
+
      
+
+
        
+
      • 
+operation_not_permitted -- if the thread does not own the lock.
+
        • 
+
      • 
+equivalent error condition from lock.lock() or lock.unlock().
+
        • 
+
      
+
+
      
+
      
+
+
      
+Change 30.5.1 [thread.condition.condvar], p26-p29:
+
      
+
+
      
+
      template <class Rep, class Period, class Predicate> 
+  bool wait_for(unique_lock<mutex>& lock, 
+                const chrono::duration<Rep, Period>& rel_time, 
+                Predicate pred);
+
      
+
      
+
      
+Precondition: lock is locked by the calling thread, and either
+
      
+
        
+
      • no other thread is waiting on this condition_variable object or
        • 
+
      • lock.mutex() returns the same value for each of the lock
+arguments supplied by all concurrently waiting threads (via wait,
+wait_for or wait_until).
        • 
+
      
+
      
+26 Effects:
+
      
+
      wait_until(lock, chrono::monotonic_clock::now() + rel_time, std::move(pred))
+
      
+
        
+
      • 
+Executes a loop:  Within the loop the function first evaluates pred()
+and exits the loop if the result of pred() is true.
+
        • 
+
      • 
+Atomically calls lock.unlock()
+and blocks on *this.
+
        • 
+
      • 
+When unblocked, calls lock.lock() (possibly blocking on the lock).
+
        • 
+
      • 
+The function will unblock when signaled by a call to notify_one(), a
+call to notify_all(), by the elapsed time rel_time passing (30.1.4
+[thread.req.timing]), or spuriously.
+
        • 
+
      • 
+If the function exits via an exception, lock.unlock() shall be called
+prior to exiting the function scope.
+
        • 
+
      • 
+The loop terminates when pred() returns true or when the time
+duration specified by rel_time has elapsed.
+
        • 
+
      
+
      
+
+
      
+27 [Note: There is no blocking if pred() is initially true,
+even if the timeout has already expired. -- end note]
+
      
+
+
      
+Postcondition: lock is locked by the calling thread.
+
      
+
+
      
+28 Returns: pred()
+
      
+
+
      
+29 [Note: The returned value indicates whether the predicate evaluates to
+true regardless of whether the timeout was triggered. -- end note]
+
      
+
+
      
+Throws: std::system_error when the effects or postcondition cannot be achieved.
+
      
+
+
      
+Error conditions:
+
      
+
+
        
+
      • 
+operation_not_permitted -- if the thread does not own the lock.
+
        • 
+
      • 
+equivalent error condition from lock.lock() or lock.unlock().
+
        • 
+
      
+
+
      
+
      
+
+
      
+Change 30.5.2 [thread.condition.condvarany], p18-19:
+
      
+
+
      
+
      template <class Lock, class Rep, class Period> 
+  bool wait_for(Lock& lock, const chrono::duration<Rep, Period>& rel_time);
+
      
+
      
+
      
+18 Effects:
+
      
+
      wait_until(lock, chrono::monotonic_clock::now() + rel_time)
+
      
+
+
        
+
      • 
+Atomically calls lock.unlock() and blocks on *this.
+
        • 
+
+
      • 
+When unblocked, calls lock.lock() (possibly blocking on the lock) and returns.
+
        • 
+
+
      • 
+The function will unblock when signaled by a call to notify_one(), a call to
+notify_all(), by
+the elapsed time rel_time passing (30.2.4 [thread.req.timing]),
+or spuriously.
+
        • 
+
+
      • 
+If the function exits via an exception, lock.unlock() shall be called
+prior to exiting the function scope.
+
        • 
+
      
+
+
      
+Postcondition: lock is locked by the calling thread.
+
      
+
+
      
+19 Returns: false if the call is returning because the time duration
+specified by rel_time has elapsed, otherwise true.
+
      
+
+
      
+Throws: std::system_error when the returned value, effects,
+or postcondition cannot be achieved.
+
      
+
+
      
+Error conditions:
+
      
+
+
        
+
      • 
+equivalent error condition from lock.lock() or lock.unlock().
+
        • 
+
      
+
      
+
      
+
+
      
+Change 30.5.2 [thread.condition.condvarany], p23-p26:
+
      
+
+
      
+
      template <class Lock, class Rep, class Period, class Predicate> 
+  bool wait_for(Lock& lock, const chrono::duration<Rep, Period>& rel_time, Predicate pred);
+
      
+
      
+
      
+Precondition: lock is locked by the calling thread, and either
+
      
+
        
+
      • no other thread is waiting on this condition_variable object or
        • 
+
      • lock.mutex() returns the same value for each of the lock
+arguments supplied by all concurrently waiting threads (via wait,
+wait_for or wait_until).
        • 
+
      
+
      
+23 Effects:
+
      
+
      wait_until(lock, chrono::monotonic_clock::now() + rel_time, std::move(pred))
+
      
+
        
+
      • 
+Executes a loop:  Within the loop the function first evaluates pred()
+and exits the loop if the result of pred() is true.
+
        • 
+
      • 
+Atomically calls lock.unlock()
+and blocks on *this.
+
        • 
+
      • 
+When unblocked, calls lock.lock() (possibly blocking on the lock).
+
        • 
+
      • 
+The function will unblock when signaled by a call to notify_one(), a
+call to notify_all(), by the elapsed time rel_time passing (30.1.4
+[thread.req.timing]), or spuriously.
+
        • 
+
      • 
+If the function exits via an exception, lock.unlock() shall be called
+prior to exiting the function scope.
+
        • 
+
      • 
+The loop terminates when pred() returns true or when the time
+duration specified by rel_time has elapsed.
+
        • 
+
      
+
      
+
+
      
+24 [Note: There is no blocking if pred() is initially true,
+even if the timeout has already expired. -- end note]
+
      
+
+
      
+Postcondition: lock is locked by the calling thread.
+
      
+
+
      
+25 Returns: pred()
+
      
+
+
      
+26 [Note: The returned value indicates whether the predicate evaluates to
+true regardless of whether the timeout was triggered. -- end note]
+
      
+
+
      
+Throws: std::system_error when the effects or postcondition cannot be achieved.
+
      
+
+
      
+Error conditions:
+
      
+
+
        
+
      • 
+operation_not_permitted -- if the thread does not own the lock.
+
        • 
+
      • 
+equivalent error condition from lock.lock() or lock.unlock().
+
        • 
+
      
+
+
      
+
      
+
+
+
+
+
+
+
 
      
 
      866. Qualification of placement new-expressions
      
-
      Section: 20.8.8 [specialized.algorithms], 20.8.10.2.6 [util.smartptr.shared.create] Status: WP
+
      Section: 20.8.13 [specialized.algorithms], 20.8.15.2.6 [util.smartptr.shared.create] Status: WP
  Submitter: Alberto Ganesh Barbati Opened: 2008-07-14  Last modified: 2009-03-09
      
 
      View all other issues in [specialized.algorithms].
      
 
      View all issues with WP status.
      
 
      Discussion:
      
 
      
 LWG issue 402 replaced "new" with "::new" in the placement
-new-expression in 20.8.4.1 [allocator.members]. I believe the rationale
+new-expression in 20.8.8.1 [allocator.members]. I believe the rationale
 given in 402 applies also to the following other contexts:
 
      
 
        
 
      • 
 
        
-in 20.8.8 [specialized.algorithms], all four algorithms unitialized_copy,
+in 20.8.13 [specialized.algorithms], all four algorithms unitialized_copy,
 unitialized_copy_n, unitialized_fill and unitialized_fill_n use
 the unqualified placement new-expression in some variation of the form:
 
        
@@ -35680,7 +38942,7 @@ the unqualified placement new-expression in some variation of the form:
 
        • 
 
      • 
 
        
-in 20.8.10.2.6 [util.smartptr.shared.create] there is a reference to the unqualified placement new-expression:
+in 20.8.15.2.6 [util.smartptr.shared.create] there is a reference to the unqualified placement new-expression:
 
        
 
        new  (pv)  T(std::forward<Args>(args)...),
 
        
@@ -35729,16 +38991,16 @@ Replace "new" with "::new" in:
 
        
 
          
 
        • 
-20.8.8.2 [uninitialized.copy], paragraphs 1 and 3
+20.8.13.2 [uninitialized.copy], paragraphs 1 and 3
 
          • 
 
        • 
-20.8.8.3 [uninitialized.fill]  paragraph 1
+20.8.13.3 [uninitialized.fill]  paragraph 1
 
          • 
 
        • 
-20.8.8.4 [uninitialized.fill.n] paragraph 1
+20.8.13.4 [uninitialized.fill.n] paragraph 1
 
          • 
 
        • 
-20.8.10.2.6 [util.smartptr.shared.create] once in paragraph 1 and twice in paragraph 2.
+20.8.15.2.6 [util.smartptr.shared.create] once in paragraph 1 and twice in paragraph 2.
 
          • 
 
        
 
@@ -35827,6 +39089,179 @@ If the bucket is empty, then b.begin(n) == b.end(n).
 
 
 
+
        
+
        876. basic_string access operations should give stronger guarantees
        
+
        Section: 21.4 [basic.string] Status: WP
+ Submitter: Daniel Krügler Opened: 2008-08-22  Last modified: 2009-10-26
        
+
        View all other issues in [basic.string].
        
+
        View all issues with WP status.
        
+
        Discussion:
        
+
        
+During the Sophia Antipolis meeting it was decided to split-off some
+parts of the
+n2647
+("Concurrency modifications for basic_string")
+proposal into a separate issue, because these weren't actually
+concurrency-related. The here proposed changes refer to the recent
+update document
+n2668
+and attempt to take advantage of the
+stricter structural requirements.
+
        
+
        
+Indeed there exists some leeway for more guarantees that would be
+very useful for programmers, especially if interaction with transactionary
+or exception-unaware C API code is important. This would also allow
+compilers to take advantage of more performance optimizations, because
+more functions can have throw() specifications. This proposal uses the
+form of "Throws: Nothing" clauses to reach the same effect, because
+there already exists a different issue in progress to clean-up the current
+existing "schizophrenia" of the standard in this regard.
+
        
+
        
+Due to earlier support for copy-on-write, we find the following
+unnecessary limitations for C++0x:
+
        
+
+
          
+
        1. 
+Missing no-throw guarantees: data() and c_str() simply return
+a pointer to their guts, which is a non-failure operation. This should
+be spelled out. It is also noteworthy to mention that the same
+guarantees should also be given by the size query functions,
+because the combination of pointer to content and the length is
+typically needed during interaction with low-level API.
+
          2. 
+
        2. 
+Missing complexity guarantees: data() and c_str() simply return
+a pointer to their guts, which is guaranteed O(1). This should be
+spelled out.
+
          3. 
+
        3. 
+Missing reading access to the terminating character: Only the
+const overload of operator[] allows reading access to the terminator
+char. For more intuitive usage of strings, reading access to this
+position should be extended to the non-const case. In contrast
+to C++03 this reading access should now be homogeneously
+an lvalue access.
+
          4. 
+
        
+
+
        
+The proposed resolution is split into a main part (A) and a
+secondary part (B) (earlier called "Adjunct Adjunct Proposal").
+(B) extends (A) by also making access to index position
+size() of the at() overloads a no-throw operation. This was
+separated, because this part is theoretically observable in
+specifically designed test programs.
+
        
+
+
        [
+San Francisco:
+]
        
+
+
+
        
+
        
+We oppose part 1 of the issue but hope to address size() in
+issue 877.
+
        
+
        
+We do not support part B. 4 of the issue because of the breaking API change.
+
        
+
        
+We support part A. 2 of the issue.
+
        
+
        
+On support part A. 3 of the issue:
+
        
+
        
+Pete's broader comment: now that we know that basic_string will be a
+block of contiguous memory, we should just rewrite its specification
+with that in mind. The expression of the specification will be simpler
+and probably more correct as a result.
+
        
+
        
+
+
        [
+2009-07 Frankfurt
+]
        
+
+
+
        
+
        
+Move proposed resolution A to Ready.
+
        
+
        [
+Howard: Commented out part B.
+]
        
+
+
        
+
+
+
+
        Proposed resolution:
        
+
          
+
        1. 
+
            
+
          1. 
+
            In 21.4.4 [string.capacity], just after p. 1 add a new paragraph:
+
            
+
            
+Throws: Nothing.
+
            
+
+
            2. 
+
          2. 
+
            
+In 21.4.5 [string.access] replace p. 1 by the following 4 paragraghs:
+
            
+
+
            
+
            
+Requires: pos ≤ size().
+
            
+
            
+Returns: If pos < size(), returns *(begin() + pos). Otherwise, returns
+a reference to a charT() that shall not be modified.
+
            
+
            
+Throws: Nothing.
+
            
+
            
+Complexity: Constant time.
+
            
+
            
+
+
            3. 
+
          3. 
+
            
+In 21.4.7.1 [string.accessors] replace the now common returns
+clause of c_str() and data() by the following three paragraphs:
+
            
+
            
+
            
+Returns: A pointer p such that p+i == &operator[](i) for each i
+in [0, size()].
+
            
+
            
+Throws: Nothing.
+
            
+
            
+Complexity: Constant time.
+
            
+
            
+
            4. 
+
          
+
          2. 
+
+
        
+
+
+
+
+
+
 
        
 
        878. forward_list preconditions
        
 
        Section: 23.3.3 [forwardlist] Status: WP
@@ -35910,6 +39345,76 @@ dereferenceable
 
 
 
+
        
+
        881. shared_ptr conversion issue
        
+
        Section: 20.8.15.2.1 [util.smartptr.shared.const] Status: WP
+ Submitter: Peter Dimov Opened: 2008-08-30  Last modified: 2009-10-26
        
+
        View all other issues in [util.smartptr.shared.const].
        
+
        View all issues with WP status.
        
+
        Discussion:
        
+
        
+We've changed shared_ptr<Y> to not convert to shared_ptr<T> when Y*
+doesn't convert to T* by resolving issue 687. This only fixed the
+converting copy constructor though.
+N2351
+later added move support, and
+the converting move constructor is not constrained.
+
        
+
+
        [
+San Francisco:
+]
        
+
+
+
        
+We might be able to move this to NAD, Editorial once shared_ptr is
+conceptualized, but we want to revisit this issue to make sure.
+
        
+
+
        [
+2009-07 Frankfurt
+]
        
+
+
+
        
+
        
+Moved to Ready.
+
        
+
        
+This issue now represents the favored format for specifying constrained templates.
+
        
+
        
+
+
+
+
        Proposed resolution:
        
+
        
+We need to change the Requires clause of the move constructor:
+
        
+
+
        shared_ptr(shared_ptr&& r); 
+template<class Y> shared_ptr(shared_ptr<Y>&& r); 
+
        
+
        
+Requires Remarks: For the second constructor Y* shall be
+convertible to T*.
+
+The second constructor shall not participate in overload resolution
+unless Y* is convertible to T*.
+
+
        
+
        
+
+
        
+in order to actually make the example in 687 compile
+(it now resolves to the move constructor).
+
        
+
+
+
+
+
+
 
        
 
        882. duration non-member arithmetic requirements
        
 
        Section: 20.9.3.5 [time.duration.nonmember] Status: CD1
@@ -36112,6 +39617,198 @@ be an instantiation of duration. Diagnostic required.
 
 
 
+
        
+
        883. swap circular definition
        
+
        Section: 23 [containers] Status: WP
+ Submitter: Alisdair Meredith Opened: 2008-09-10  Last modified: 2009-10-26
        
+
        View other active issues in [containers].
        
+
        View all other issues in [containers].
        
+
        View all issues with WP status.
        
+
        Discussion:
        
+
+
        
+Note in particular that Table 90 "Container Requirements" gives
+semantics of a.swap(b) as swap(a,b), yet for all
+containers we define swap(a,b) to call a.swap(b) - a
+circular definition.
+
        
+
+
        [
+San Francisco:
+]
        
+
+
+
        
+Robert to propose a resolution along the lines of "Postcondition: "a =
+b, b = a" This will be a little tricky for the hash containers, since
+they don't have operator==.
+
        
+
+
        [
+Post Summit Anthony Williams provided proposed wording.
+]
        
+
+
+
        [
+2009-07 Frankfurt
+]
        
+
+
+
        
+Moved to Ready with minor edits (which have been made).
+
        
+
+
+
+
        Proposed resolution:
        
+
        
+In table 80 in section 23.2.1 [container.requirements.general],
+replace the postcondition of a.swap(b) with the following:
+
        
+
+
        
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
        Table 80 -- Container requirements
        ExpressionReturn typeOperational semanticsAssertion/note pre-/post-conidtionComplexity
        ...............
        a.swap(b);void swap(a,b)
+Exchange the contents of a and b.(Note A)
        
+
        
+
+
        
+Remove the reference to swap from the paragraph following the table.
+
        
+
+
        
+Notes: the algorithms swap(), equal() and
+lexicographical_compare() are defined in Clause 25. ...
+
        
+
+
+
+
+
+
        
+
        886. tuple construction
        
+
        Section: 20.5.2.1 [tuple.cnstr] Status: WP
+ Submitter: Alisdair Meredith Opened: 2008-09-15  Last modified: 2009-10-26
        
+
        View all other issues in [tuple.cnstr].
        
+
        View all issues with WP status.
        
+
        Discussion:
        
+
        
+20.5.2.1 [tuple.cnstr]:
+
        
+
        
+Effects: Default initializes each element.
+
        
+
+
        
+Could be clarified to state each "non-trivial" element.  Otherwise
+we have a conflict with Core deinfition of default initialization -
+trivial types do not get initialized (rather than initialization
+having no effect)
+
        
+
+
        
+I'm going to punt on this one, because it's not an issue that's
+related to concepts. I suggest bringing it to Howard's attention on
+the reflector.
+
        
+
+
        [
+San Francisco:
+]
        
+
+
+
        
+
        
+Text in draft doesn't mean anything, changing to "non-trivial" makes it
+meaningful.
+
        
+
        
+We prefer "value initializes". Present implementations use
+value-initialization. Users who don't want value initialization have
+alternatives.
+
        
+
        
+Request resolution text from Alisdair.
+
        
+
+
        
+This issue relates to Issue 868 default construction and value-initialization.
+
        
+
        
+
+
        [
+2009-05-04 Alisdair provided wording and adds:
+]
        
+
+
+
        
+
        
+Note: This IS a change of semantic from TR1, although one the room agreed
+with during the discussion.  To preserve TR1 semantics, this would have been
+worded:
+
        
+
        requires DefaultConstructible<Types>... tuple();
+
        
+
        
+-2-   Effects: Default-initializes each non-trivial element.
+
        
+
        
+
+
+
        
+
+
        [
+2009-07 Frankfurt
+]
        
+
+
+
        
+Move to Ready.
+
        
+
+
+
+
        Proposed resolution:
        
+
        
+Change p2 in Construction 20.5.2.1 [tuple.cnstr]:
+
        
+
+
        requires DefaultConstructible<Types>... tuple();
+
        
+
        
+
        
+-2- Effects: Default Value-initializes each element.
+
        
+
        
+
        
+
+
+
+
+
+
 
        
 
        888. this_thread::yield too strong
        
 
        Section: 30.3.2 [thread.thread.this] Status: WP
@@ -36285,7 +39982,7 @@ been implemented. Seems to be widespread consensus. Move to Tentative Ready.
 
 
        Proposed resolution:
        
 
-
        Change 17.6.4.12 [value.error.codes] Value of error codes as indicated:
        
+
        Change 17.6.4.13 [value.error.codes] Value of error codes as indicated:
        
 
        
  
        Certain functions in the C++ standard library report errors via a 
  std::error_code (19.4.2.2) object. That object's category() member shall 
@@ -36366,7 +40063,7 @@ Thus implementations are given latitude in determining correspondence.
 
 
        
 
-
        Change 19.5.2.3 [syserr.errcode.constructors] Class error_code constructors 
+
        Change 19.5.2.2 [syserr.errcode.constructors] Class error_code constructors 
 as indicated:
        
 
        
  
        error_code();
        
@@ -36375,7 +40072,7 @@ as indicated:
        
  
        Postconditions: val_ == 0 and cat_ == &system_category().
        
  
        
 
      
-
      Change 19.5.2.4 [syserr.errcode.modifiers] Class error_code modifiers as 
+
      Change 19.5.2.3 [syserr.errcode.modifiers] Class error_code modifiers as 
 indicated:
      
 
      
  
      void clear();
      
@@ -36384,7 +40081,7 @@ indicated:
      
  system_category().
      
  
      
 
      5. 
-
      Change 19.5.2.6 [syserr.errcode.nonmembers] Class error_code non-member 
+
      Change 19.5.2.5 [syserr.errcode.nonmembers] Class error_code non-member 
 functions as indicated:
      
 
      
  
      error_code make_error_code(errc e);
      
@@ -36392,7 +40089,7 @@ functions as indicated:
      
  
      Returns: error_code(static_cast<int>(e), generic_category()).
      
  
      
 
    
-
    Change 19.5.3.3 [syserr.errcondition.constructors] Class error_condition 
+
    Change 19.5.3.2 [syserr.errcondition.constructors] Class error_condition 
 constructors as indicated:
    
 
    
  
    error_condition();
    
@@ -36401,7 +40098,7 @@ constructors as indicated:
    
  
    Postconditions: val_ == 0 and cat_ == &generic_category().
    
  
    
 
    
-
    Change 19.5.3.4 [syserr.errcondition.modifiers] Class error_condition 
+
    Change 19.5.3.3 [syserr.errcondition.modifiers] Class error_condition 
 modifiers as indicated:
    
 
    
  
    void clear();
    
@@ -36410,7 +40107,7 @@ modifiers as indicated:
    
  generic_category().
    
  
    
 
    
-
    Change 19.5.3.6 [syserr.errcondition.nonmembers] Class error_condition 
+
    Change 19.5.3.5 [syserr.errcondition.nonmembers] Class error_condition 
 non-member functions as indicated:
    
 
    
  
    error_condition make_error_condition(errc e);
    
@@ -36506,7 +40203,6 @@ any automatic objects.
 
    898. Small contradiction in n2723 to forward to committee
    
 
    Section: 23.3.3.5 [forwardlist.ops] Status: WP
  Submitter: Arch Robison Opened: 2008-09-08  Last modified: 2009-07-18
    
-
    View other active issues in [forwardlist.ops].
    
 
    View all other issues in [forwardlist.ops].
    
 
    View all issues with WP status.
    
 
    Discussion:
    
@@ -36563,7 +40259,7 @@ comparisons.
 
 
    
 
    899. Adjusting shared_ptr for nullptr_t
    
-
    Section: 20.8.10.2.2 [util.smartptr.shared.dest] Status: WP
+
    Section: 20.8.15.2.2 [util.smartptr.shared.dest] Status: WP
  Submitter: Peter Dimov Opened: 2008-09-18  Last modified: 2009-07-18
    
 
    View all other issues in [util.smartptr.shared.dest].
    
 
    View all issues with WP status.
    
@@ -36574,13 +40270,13 @@ James Dennett, message c++std-lib-22442:
 
    
 The wording below addresses one case of this, but opening an
 issue to address the need to sanity check uses of the term "pointer"
-in 20.8.10.2 [util.smartptr.shared] would be a good thing.
+in 20.8.15.2 [util.smartptr.shared] would be a good thing.
 
    
 
    
 There's one more reference, in ~shared_ptr; we can apply your suggested change to it, too. That is:
 
    
 
    
-Change 20.8.10.2.2 [util.smartptr.shared.dest]/1 second bullet from:
+Change 20.8.15.2.2 [util.smartptr.shared.dest]/1 second bullet from:
 
    
 
    
 Otherwise, if *this owns a pointer p and a deleter d, d(p) is called.
@@ -36609,7 +40305,7 @@ Batavia (2009-05):
 
    
 Peter Dimov notes the analogous change has already been made
 to "the new nullptr_t taking constructors
-in 20.8.10.2.1 [util.smartptr.shared.const] p9-13."
+in 20.8.15.2.1 [util.smartptr.shared.const] p9-13."
 
    
 
    
 We agree with the proposed resolution.
@@ -36620,7 +40316,7 @@ Move to Tentatively Ready.
 
 
    Proposed resolution:
    
 
    
-Change 20.8.10.2.2 [util.smartptr.shared.dest]/1 second bullet:
+Change 20.8.15.2.2 [util.smartptr.shared.dest]/1 second bullet:
 
    
 
    
 
      
@@ -36641,6 +40337,7 @@ deleter d, d(p) is called.
 
      904. result_of argument types
      
 
      Section: 20.7.4 [func.ret] Status: WP
  Submitter: Jonathan Wakely Opened: 2008-09-10  Last modified: 2009-07-18
      
+
      View all other issues in [func.ret].
      
 
      View all issues with WP status.
      
 
      Discussion:
      
 
      
@@ -36707,7 +40404,7 @@ and rvalues otherwise.
 
 
      
 
      907. Bitset's immutable element retrieval is inconsistently defined
      
-
      Section: 20.3.6.2 [bitset.members] Status: WP
+
      Section: 20.3.7.2 [bitset.members] Status: WP
  Submitter: Daniel Krügler Opened: 2008-09-26  Last modified: 2009-07-18
      
 
      View all other issues in [bitset.members].
      
 
      View all issues with WP status.
      
@@ -36716,8 +40413,8 @@ and rvalues otherwise.
 The current standard 14882::2003(E) as well as the current draft
 N2723
 have in common a contradiction of the operational semantics
-of member function test 20.3.6.2 [bitset.members]/56-58 and the immutable
-member operator[] overload 20.3.6.2 [bitset.members]/64-66 (all references
+of member function test 20.3.7.2 [bitset.members]/56-58 and the immutable
+member operator[] overload 20.3.7.2 [bitset.members]/64-66 (all references
 are defined in terms of
 N2723):
 
      
@@ -36799,8 +40496,8 @@ Proposed alternatives:
 
      
 Remove the constexpr specifier in front of operator[] overload and
 undo that of member test (assuming 720 is accepted) in both the
-class declaration 20.3.6 [template.bitset]/1 and in the member description
-before 20.3.6.2 [bitset.members]/56 and before /64 to read:
+class declaration 20.3.7 [template.bitset]/1 and in the member description
+before 20.3.7.2 [bitset.members]/56 and before /64 to read:
 
      
 
      constexpr bool test(size_t pos) const;
 ..
@@ -36830,8 +40527,8 @@ position nothing.
 
    • 
 
      
 Undo the addition of the constexpr specifier to the test member
-function in both class declaration 20.3.6 [template.bitset]/1 and in the
-member description before 20.3.6.2 [bitset.members]/56, assuming that 720
+function in both class declaration 20.3.7 [template.bitset]/1 and in the
+member description before 20.3.7.2 [bitset.members]/56, assuming that 720
 was applied.
 
      
 
@@ -36879,8 +40576,8 @@ Move to Tentatively Ready.
 
    • 
 
      
 Undo the addition of the constexpr specifier to the test member
-function in both class declaration 20.3.6 [template.bitset]/1 and in the
-member description before 20.3.6.2 [bitset.members]/56, assuming that 720
+function in both class declaration 20.3.7 [template.bitset]/1 and in the
+member description before 20.3.7.2 [bitset.members]/56, assuming that 720
 was applied.
 
      
 
@@ -37057,7 +40754,7 @@ by the iterator range [&submatches,&submatches + N)
 
      Addresses DE 24
      
 
 
      
-With respect to the section 20.7.12.1.4 [func.bind.place]:
+With respect to the section 20.7.11.1.4 [func.bind.place]:
 
      
 
      
 TR1 dropped some suggested implementation quantities for the number of
@@ -37082,7 +40779,7 @@ Tentatively Ready.
 Original proposed resolution:
 
 
      
-Add 20.7.12.1.4 [func.bind.place]/2:
+Add 20.7.11.1.4 [func.bind.place]/2:
 
      
 
 
      
@@ -37100,7 +40797,7 @@ Add to B [implimits]:
 
 
        
 
      • 
-Number of placeholders (20.7.12.1.4 [func.bind.place]) [10].
+Number of placeholders (20.7.11.1.4 [func.bind.place]) [10].
 
        • 
 
      
 
@@ -37111,16 +40808,15 @@ Number of placeholders (20.7.12.1.4 [func.bind.place]) [10].
 
 
      
 
      925. shared_ptr's explicit conversion from unique_ptr
      
-
      Section: 20.8.10.2.1 [util.smartptr.shared.const] Status: WP
+
      Section: 20.8.15.2.1 [util.smartptr.shared.const] Status: WP
  Submitter: Rodolfo Lima Opened: 2008-10-12  Last modified: 2009-07-18
      
-
      View other active issues in [util.smartptr.shared.const].
      
 
      View all other issues in [util.smartptr.shared.const].
      
 
      View all issues with WP status.
      
 
      Discussion:
      
 
      
 The current working draft
 (N2798),
-section 20.8.10.2.1 [util.smartptr.shared.const] declares
+section 20.8.15.2.1 [util.smartptr.shared.const] declares
 shared_ptr's constructor that takes a rvalue reference to unique_ptr and
 auto_ptr as being explicit, affecting several valid smart pointer use
 cases that would take advantage of this conversion being implicit, for
@@ -37181,8 +40877,8 @@ Move to Tentatively Ready.
 
 
      Proposed resolution:
      
 
      
-In both 20.8.10.2 [util.smartptr.shared] paragraph 1 and 
-20.8.10.2.1 [util.smartptr.shared.const] change:
+In both 20.8.15.2 [util.smartptr.shared] paragraph 1 and 
+20.8.15.2.1 [util.smartptr.shared.const] change:
 
      
 
 
      template <class Y> explicit shared_ptr(auto_ptr<Y> &&r);
@@ -37291,9 +40987,186 @@ Wording supplied by Daniel.
 
 
 
+
      
+
      934. duration is missing operator%
      
+
      Section: 20.9.3 [time.duration] Status: WP
+ Submitter: Terry Golubiewski Opened: 2008-11-30  Last modified: 2009-10-26
      
+
      View other active issues in [time.duration].
      
+
      View all other issues in [time.duration].
      
+
      View all issues with WP status.
      
+
      Discussion:
      
+
+
      Addresses US 81
      
+
+
      
+duration is missing operator%.  This operator is convenient
+for computing where in a time frame a given duration lies.  A
+motivating example is converting a duration into a "broken-down"
+time duration such as hours::minutes::seconds:
+
      
+
+
      class ClockTime
+{
+    typedef std::chrono::hours hours;
+    typedef std::chrono::minutes minutes;
+    typedef std::chrono::seconds seconds;
+public:
+    hours hours_;
+    minutes minutes_;
+    seconds seconds_;
+
+    template <class Rep, class Period>
+      explicit ClockTime(const std::chrono::duration<Rep, Period>& d)
+        : hours_  (std::chrono::duration_cast<hours>  (d)),
+          minutes_(std::chrono::duration_cast<minutes>(d % hours(1))),
+          seconds_(std::chrono::duration_cast<seconds>(d % minutes(1)))
+          {}
+};
+
      
+
+
      [
+Summit:
+]
      
+
+
+
      
+Agree except that there is a typo in the proposed resolution. The member
+operators should be operator%=.
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+We agree with the proposed resolution.
+Move to Tentatively Ready.
+
      
+
+
      [
+2009-07 Frankfurt
+]
      
+
+
+
      
+Moved from Tentatively Ready to Open only because the wording needs to be
+improved for enable_if type constraining, possibly following Robert's
+formula.
+
      
+
+
      [
+2009-07 Frankfurt:
+]
      
+
+
+
      
+
      
+Howard to open a separate issue (1177) to handle the removal of member
+functions from overload sets, provide wording, and possibly demonstrate
+how this can be implemented using enable_if (see 947).
+
      
+
      
+Move to Ready.
+
      
+
      
+
+
+
+
      Proposed resolution:
      
+
      
+Add to the synopsis in 20.9 [time]:
+
      
+
+
      template <class Rep1, class Period, class Rep2>
+  duration<typename common_type<Rep1, Rep2>::type, Period>
+  operator%(const duration<Rep1, Period>& d, const Rep2& s);
+template <class Rep1, class Period1, class Rep2, class Period2>
+  typename common_type<duration<Rep1, Period1>, duration<Rep2, Period2>>::type
+  operator%(const duration<Rep1, Period1>& lhs, const duration<Rep2, Period2>& rhs);
+
      
+
+
      
+Add to the synopsis of duration in 20.9.3 [time.duration]:
+
      
+
+
      template <class Rep, class Period = ratio<1>>
+class duration {
+public:
+  ...
+  duration& operator%=(const rep& rhs);
+  duration& operator%=(const duration& d);
+  ...
+};
+
      
+
+
      
+Add to 20.9.3.3 [time.duration.arithmetic]:
+
      
+
+
      
+
      duration& operator%=(const rep& rhs);
+
      
+
      
+
      
+Effects: rep_ %= rhs.
+
      
+
      
+Returns: *this.
+
      
+
      
+
+
      duration& operator%=(const duration& d);
+
      
+
      
+
      
+Effects: rep_ %= d.count().
+
      
+
      
+Returns: *this.
+
      
+
      
+
      
+
+
      
+Add to 20.9.3.5 [time.duration.nonmember]:
+
      
+
+
      
+
+
      template <class Rep1, class Period, class Rep2>
+  duration<typename common_type<Rep1, Rep2>::type, Period>
+  operator%(const duration<Rep1, Period>& d, const Rep2& s);
+
      
+
      
+
      
+Requires: Rep2 shall be implicitly convertible to CR(Rep1, Rep2) and
+Rep2 shall not be an instantiation of duration. Diagnostic required.
+
      
+
      
+Returns: duration<CR, Period>(d) %= s.
+
      
+
      
+
+
      template <class Rep1, class Period1, class Rep2, class Period2>
+  typename common_type<duration<Rep1, Period1>, duration<Rep2, Period2>>::type
+  operator%(const duration<Rep1, Period1>& lhs, const duration<Rep2, Period2>& rhs);
+
      
+
      
+
      
+Returns: common_type<duration<Rep1, Period1>, duration<Rep2, Period2>>::type(lhs) %= rhs.
+
      
+
      
+
+
      
+
+
+
+
+
+
 
      
 
      938. default_delete<T[]>::operator() should only accept T*
      
-
      Section: 20.8.9.1.2 [unique.ptr.dltr.dflt1] Status: WP
+
      Section: 20.8.14.1.2 [unique.ptr.dltr.dflt1] Status: WP
  Submitter: Howard Hinnant Opened: 2008-12-07  Last modified: 2009-07-18
      
 
      View all issues with WP status.
      
 
      Discussion:
      
@@ -37332,7 +41205,7 @@ Move to Tentatively Ready.
 
 
      Proposed resolution:
      
 
      
-Add to 20.8.9.1.2 [unique.ptr.dltr.dflt1]:
+Add to 20.8.14.1.2 [unique.ptr.dltr.dflt1]:
 
      
 
 
      namespace std {
@@ -37508,12 +41381,12 @@ If overflow occurs, a diagnostic shall be issued.
 
 
      
 
      949. owner_less
      
-
      Section: 20.8.10.4 [util.smartptr.ownerless] Status: WP
+
      Section: 20.8.15.3.7 [util.smartptr.ownerless] Status: WP
  Submitter: Thomas Plum Opened: 2008-12-30  Last modified: 2009-07-18
      
 
      View all issues with WP status.
      
 
      Discussion:
      
 
      
-20.8.10.4 [util.smartptr.ownerless] (class template owner_less) says that 
+20.8.15.3.7 [util.smartptr.ownerless] (class template owner_less) says that 
 operator()(x,y) shall return x.before(y).
 
      
 
      
@@ -37547,7 +41420,7 @@ Recommend Tentatively Ready.
 
 
      Proposed resolution:
      
 
      
-Change 20.8.10.4 [util.smartptr.ownerless] p2:
+Change 20.8.15.3.7 [util.smartptr.ownerless] p2:
 
      
 
 
      
@@ -37624,13 +41497,11 @@ previously-initialized but as of yet undestroyed
 
 
      
 
      970. addressof overload unneeded
      
-
      Section: 20.8.8.1 [object.addressof] Status: WP
- Submitter: Howard Hinnant Opened: 2009-01-16  Last modified: 2009-07-18
      
-
      View all other issues in [object.addressof].
      
-
      View all issues with WP status.
      
+
      Section: X [object.addressof] Status: Pending WP
+ Submitter: Howard Hinnant Opened: 2009-01-16  Last modified: 2009-09-25
      
 
      Discussion:
      
 
      
-20.8.8.1 [object.addressof] specifies:
+X [object.addressof] specifies:
 
      
 
 
      template <ObjectType T> T* addressof(T& r);
@@ -37664,7 +41535,7 @@ Move to Tentatively Ready.
 
 
      Proposed resolution:
      
 
      
-Change 20.8.8.1 [object.addressof]:
+Change X [object.addressof]:
 
      
 
 
      template <ObjectType T> T* addressof(T& r);
@@ -38056,6 +41927,7 @@ In 23.2.5 [unord.req], Table 87 insert:
 
      982. Wrong complexity for initializer_list assignment in  Table 85
      
 
      Section: 23.2.4 [associative.reqmts] Status: WP
  Submitter: Daniel Krügler Opened: 2009-02-08  Last modified: 2009-07-18
      
+
      View other active issues in [associative.reqmts].
      
 
      View all other issues in [associative.reqmts].
      
 
      View all issues with WP status.
      
 
      Discussion:
      
@@ -38431,7 +42303,7 @@ functions passed to atexit() (3.6.3 [basic.start.term]).
 
 
      
 
      994. Response to UK 193
      
-
      Section: 18.6.2.2 [new.handler] Status: WP
+
      Section: 18.6.2.3 [new.handler] Status: WP
  Submitter: P.J. Plauger Opened: 2009-03-03  Last modified: 2009-07-18
      
 
      View all issues with WP status.
      
 
      Discussion:
      
@@ -38452,7 +42324,7 @@ Move to Tentatively Ready.
 
 
      Proposed resolution:
      
 
      
-Change 18.6.2.2 [new.handler], p2:
+Change 18.6.2.3 [new.handler], p2:
 
      
 
 
      
@@ -38596,7 +42468,7 @@ supersedes any occurrences of that element in the code-sequence.
 
 
      
 
      998. Smart pointer referencing its owner
      
-
      Section: 20.8.9.2.5 [unique.ptr.single.modifiers] Status: WP
+
      Section: 20.8.14.2.5 [unique.ptr.single.modifiers] Status: WP
  Submitter: Pavel Minaev Opened: 2009-02-26  Last modified: 2009-07-18
      
 
      View all other issues in [unique.ptr.single.modifiers].
      
 
      View all issues with WP status.
      
@@ -38723,7 +42595,7 @@ Move to Tentatively Ready.
 
 
      Proposed resolution:
      
 
      
-Change 20.8.9.2.5 [unique.ptr.single.modifiers], p5 (Effects clause for reset), and p6:
+Change 20.8.14.2.5 [unique.ptr.single.modifiers], p5 (Effects clause for reset), and p6:
 
      
 
 
      
@@ -38747,6 +42619,65 @@ expression. -- end note]
 
 
 
+
      
+
      1004. Response to UK 179
      
+
      Section: 17.6.3.8 [res.on.functions] Status: WP
+ Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-10-26
      
+
      View all other issues in [res.on.functions].
      
+
      View all issues with WP status.
      
+
      Discussion:
      
+
+
      Addresses UK 179
      
+
+
      
+According to the 4th bullet there is a problem if "if any replacement
+function or handler function or destructor operation throws an
+exception". There should be no problem throwing exceptions so long as
+they are caught within the function.
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+The phrasing "throws an exception" is commonly used elsewhere
+to mean "throws or propagates an exception."
+Move to Open pending a possible more general resolution.
+
      
+
+
      [
+2009-07 Frankfurt:
+]
      
+
+
+
      
+Replace "propagates" in the proposed resolution with the phrase "exits
+via" and move to Ready.
+
      
+
+
+
+
      Proposed resolution:
      
+
      
+Change the 4th bullet of 17.6.3.8 [res.on.functions], p2:
+
      
+
+
      
+
        
+
      • 
+if any replacement function or handler function or destructor operation
+throws exits via an exception, unless specifically
+allowed in the applicable Required behavior: paragraph.
+
        • 
+
      
+
      
+
+
+
+
+
+
 
      
 
      1006. operator delete in garbage collected implementation
      
 
      Section: 18.6.1 [new.delete] Status: WP
@@ -38913,6 +42844,112 @@ be a safely-derived pointer.
 
 
 
+
      
+
      1012. reverse_iterator default ctor should value initialize
      
+
      Section: 24.5.1.3.1 [reverse.iter.cons] Status: WP
+ Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-10-26
      
+
      View all issues with WP status.
      
+
      Discussion:
      
+
+
      Addresses UK 277
      
+
+
      
+The default constructor default-initializes current, rather than
+value-initializes. This means that when Iterator corresponds to a
+trivial type, the current member is left un-initialized, even when the
+user explictly requests value intialization! At this point, it is not
+safe to perform any operations on the reverse_iterator other than assign
+it a new value or destroy it. Note that this does correspond to the
+basic definition of a singular iterator.
+
      
+
+
      [
+Summit:
+]
      
+
+
+
      
+Agree with option i.
+
      
+
+
      
+Related issue: 408
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+We believe this should be revisited
+in conjunction with issue 408,
+which nearly duplicates this issue.
+Move to Open.
+
      
+
+
      [
+2009-07 post-Frankfurt:
+]
      
+
+
+
      
+
      
+Change "constructed" to "initialized" in two places in the proposed resolution.
+
      
+
      
+Move to Tentatively Ready.
+
      
+
      
+
+
      [
+2009 Santa Cruz:
+]
      
+
+
+
      
+Moved to Ready for this meeting.
+
      
+
+
+
+
      Proposed resolution:
      
+
      
+Change  [reverse.iter.con]:
+
      
+
+
      reverse_iterator();
+
      
+
      
+-1- Effects: Default Value initializes current. Iterator
+operations applied to the resulting iterator have defined behavior if and
+only if the corresponding operations are defined on a default constructed
+value initialized
+iterator of type Iterator.
+
      
+
      
+
+
      
+Change 24.5.3.3.1 [move.iter.op.const]:
+
      
+
+
      move_iterator();
+
      
+
      
+-1- Effects: Constructs a move_iterator, default value
+initializing current.
+Iterator
+operations applied to the resulting iterator have defined behavior if and
+only if the corresponding operations are defined on a
+value initialized
+iterator of type Iterator.
+
      
+
      
+
+
+
+
+
+
 
      
 
      1014. Response to UK 317 and JP 74
      
 
      Section: 28.8.2 [re.regex.construct] Status: WP
@@ -38989,9 +43026,121 @@ Add in  28.8.2 [re.regex.construct]:
 
 
 
+
      
+
      1019. Response to UK 205
      
+
      Section: 20.6.3 [meta.help] Status: WP
+ Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-10-26
      
+
      View all other issues in [meta.help].
      
+
      View all issues with WP status.
      
+
      Discussion:
      
+
+
      Addresses UK 205
      
+
+
      
+integral_constant objects should be usable in integral-constant-expressions.
+The addition to the language of literal types and the enhanced rules for
+constant expressions make this possible.
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+We agree that the static data member
+ought be declared constexpr,
+but do not see a need for the proposed operator value_type().
+(A use case would be helpful.)
+Move to Open.
+
      
+
+
      [
+2009-05-23 Alisdair adds:
+]
      
+
+
+
      
+
      
+The motivating case in my mind is that we can then use
+true_type and false_type as integral Boolean expressions, for example inside
+a static_assert declaration.  In that sense it is purely a matter of style.
+
      
+
      
+Note that Boost has applied the non-explicit conversion operator for many
+years as it has valuable properties for extension into other metaprogramming
+libraries, such as MPL.  If additional rationale is desired I will poll the
+Boost lists for why this extension was originally applied.  I would argue
+that explicit conversion is more appropriate for 0x though.
+
      
+
      
+
+
      [
+2009-07-04 Howard adds:
+]
      
+
+
+
      
+
      
+Here's a use case which demonstrates the syntactic niceness which Alisdair describes:
+
      
+
+
      #define requires(...) class = typename std::enable_if<(__VA_ARGS__)>::type
+
+template <class T, class U,
+    requires(!is_lvalue_reference<T>() ||
+              is_lvalue_reference<T>() && is_lvalue_reference<U>()),
+    requires(is_same<typename base_type<T>::type,
+                     typename base_type<U>::type>)>
+inline
+T&&
+forward(U&& t)
+{
+    return static_cast<T&&>(t);
+}
+
      
+
      
+
+
      [
+2009-07 post-Frankfurt:
+]
      
+
+
+
      
+Move to Tentatively Ready.
+
      
+
+
      [
+2009 Santa Cruz:
+]
      
+
+
+
      
+Moved to Ready for this meeting.
+
      
+
+
+
+
      Proposed resolution:
      
+
      
+Add to the integral_constant struct definition in 20.6.3 [meta.help]:
+
      
+
+
      template <class T, T v>
+struct integral_constant {
+  static constexpr T value = v;
+  typedef T value_type;
+  typedef integral_constant<T,v> type;
+  constexpr operator value_type() { return value; }
+};
+
      
+
+
+
+
+
 
      
 
      1021. Response to UK 211
      
-
      Section: 20.8.9.2.3 [unique.ptr.single.asgn] Status: WP
+
      Section: 20.8.14.2.3 [unique.ptr.single.asgn] Status: WP
  Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-07-18
      
 
      View all issues with WP status.
      
 
      Discussion:
      
@@ -39016,14 +43165,14 @@ Move to Tentatively Ready.
 
 
      Proposed resolution:
      
 
      
-Change the synopsis in 20.8.9.2 [unique.ptr.single]:
+Change the synopsis in 20.8.14.2 [unique.ptr.single]:
 
      
 
 
      unique_ptr& operator=(unspecified-pointer-type nullptr_t);
 
      
 
 
      
-Change 20.8.9.2.3 [unique.ptr.single.asgn]:
+Change 20.8.14.2.3 [unique.ptr.single.asgn]:
 
      
 
 
      unique_ptr& operator=(unspecified-pointer-type nullptr_t);
@@ -39044,6 +43193,7 @@ private data member, avoiding many of the implicit conversion pitfalls.
 
      1037. Response to UK 232
      
 
      Section: 23.2.3 [sequence.reqmts] Status: WP
  Submitter: Alisdair Meredith Opened: 2009-03-12  Last modified: 2009-07-18
      
+
      View other active issues in [sequence.reqmts].
      
 
      View all other issues in [sequence.reqmts].
      
 
      View all issues with WP status.
      
 
      Discussion:
      
@@ -39092,6 +43242,7 @@ In 23.2.3 [sequence.reqmts] Table 84, remove reference to
 
      1038. Response to UK 233
      
 
      Section: 23.2.3 [sequence.reqmts] Status: WP
  Submitter: Alisdair Meredith Opened: 2009-03-12  Last modified: 2009-07-18
      
+
      View other active issues in [sequence.reqmts].
      
 
      View all other issues in [sequence.reqmts].
      
 
      View all issues with WP status.
      
 
      Discussion:
      
@@ -39195,6 +43346,7 @@ containers to the following rows:
 
      1039. Response to UK 234
      
 
      Section: 23.2.3 [sequence.reqmts] Status: WP
  Submitter: Alisdair Meredith Opened: 2009-03-12  Last modified: 2009-07-18
      
+
      View other active issues in [sequence.reqmts].
      
 
      View all other issues in [sequence.reqmts].
      
 
      View all issues with WP status.
      
 
      Discussion:
      
@@ -39258,6 +43410,7 @@ In 23.2.3 [sequence.reqmts] Table 84, replace iterator with auto in semantics fo
 
      1040. Response to UK 238
      
 
      Section: 23.2.4 [associative.reqmts] Status: WP
  Submitter: Alisdair Meredith Opened: 2009-03-12  Last modified: 2009-07-18
      
+
      View other active issues in [associative.reqmts].
      
 
      View all other issues in [associative.reqmts].
      
 
      View all issues with WP status.
      
 
      Discussion:
      
@@ -39603,13 +43756,13 @@ In the synopsis of 18.8.6 [except.nested] and the definition area change:
 
 
      
 
      1070. Ambiguous move overloads in function
      
-
      Section: 20.7.16.2 [func.wrap.func] Status: WP
+
      Section: 20.7.15.2 [func.wrap.func] Status: WP
  Submitter: Howard Hinnant Opened: 2009-03-19  Last modified: 2009-07-18
      
 
      View all other issues in [func.wrap.func].
      
 
      View all issues with WP status.
      
 
      Discussion:
      
 
      
-The synopsis in 20.7.16.2 [func.wrap.func] says:
+The synopsis in 20.7.15.2 [func.wrap.func] says:
 
      
 
 
      template<Returnable R, CopyConstructible... ArgTypes> 
@@ -39673,8 +43826,8 @@ Move to Tentatively Ready.
 
 
      Proposed resolution:
      
 
      
-Change the synopsis of 20.7.16.2 [func.wrap.func], and remove the associated definitions in
-20.7.16.2.1 [func.wrap.func.con]:
+Change the synopsis of 20.7.15.2 [func.wrap.func], and remove the associated definitions in
+20.7.15.2.1 [func.wrap.func.con]:
 
      
 
 
      template<Returnable R, CopyConstructible... ArgTypes> 
@@ -39997,4 +44150,38 @@ need not be repeated here).
 
 
 
+
      
+
      1178. Header dependencies
      
+
      Section: 17.6.4.2 [res.on.headers] Status: WP
+ Submitter: Beman Dawes Opened: 2009-07-18  Last modified: 2009-10-26
      
+
      View all issues with WP status.
      
+
      Discussion:
      
+
      
+See Frankfurt notes of 1001.
+
      
+
+
+
      Proposed resolution:
      
+
      Change 17.6.4.2 [res.on.headers], Headers, paragraph 1, as indicated:
      
+
+
      
+
+
      
+A C++ header may include other C++
+headers.[footnote] A C++ header shall provide
+the declarations and definitions that appear in its synopsis
+(3.2 [basic.def.odr]). A C++ header shown in its synopsis as including 
+other C++ headers shall provide the declarations and definitions that appear in
+the synopses of those other headers.
+
      
+
+  
      [footnote] C++ headers must include a C++ header that contains 
+  any needed definition (3.2).
      
+
      
+
+
+
+
+
+
 
\ No newline at end of file
diff --git a/libstdc++-v3/doc/xml/manual/intro.xml b/libstdc++-v3/doc/xml/manual/intro.xml
index 33bacae60b0..da06cd90525 100644
--- a/libstdc++-v3/doc/xml/manual/intro.xml
+++ b/libstdc++-v3/doc/xml/manual/intro.xml
@@ -628,7 +628,7 @@ requirements of the license of GCC.
     Have open clear the error flags.
     
 
-    431:
+    431:
         Swapping containers with unequal allocators
     
     Implement Option 3, as per N1599.
@@ -729,7 +729,7 @@ requirements of the license of GCC.
     Add the missing modes to fopen_mode.
     
 
-    630:
+    630:
         arrays of valarray
     
     Implement the simple resolution.
@@ -760,7 +760,7 @@ requirements of the license of GCC.
     Make the member functions table and classic_table public.
     
 
-    696:
+    696:
         istream::operator>>(int&) broken
     
     Implement the straightforward resolution.