bc225f98dd
2003-11-18 Jonathan Wakely <redi@gcc.gnu.org> * docs/html/configopts.html, docs/html/debug.html, docs/html/documentation.html, docs/html/explanations.html, docs/html/install.html, docs/html/17_intro/contribute.html, docs/html/17_intro/howto.html, docs/html/17_intro/license.html, docs/html/18_support/howto.html, docs/html/19_diagnostics/howto.html, docs/html/20_util/howto.html, docs/html/21_strings/howto.html, docs/html/22_locale/codecvt.html, docs/html/22_locale/ctype.html, docs/html/22_locale/howto.html, docs/html/22_locale/locale.html, docs/html/22_locale/messages.html, docs/html/23_containers/howto.html, docs/html/24_iterators/howto.html, docs/html/25_algorithms/howto.html, docs/html/26_numerics/howto.html, docs/html/27_io/howto.html, docs/html/ext/howto.html, docs/html/ext/sgiexts.html: Add <link> tags. From-SVN: r73712
254 lines
11 KiB
HTML
254 lines
11 KiB
HTML
<?xml version="1.0" encoding="ISO-8859-1"?>
|
|
<!DOCTYPE html
|
|
PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
|
|
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
|
|
|
|
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
|
|
<head>
|
|
<meta name="AUTHOR" content="pme@gcc.gnu.org (Phil Edwards)" />
|
|
<meta name="KEYWORDS" content="libstdc++, libstdc++-v3, GCC, g++, STL, SGI" />
|
|
<meta name="DESCRIPTION" content="SGI extensions preserved in libstdc++-v3." />
|
|
<meta name="GENERATOR" content="vi and eight fingers" />
|
|
<title>SGI extensions to the library in libstdc++-v3</title>
|
|
<link rel="StyleSheet" href="../lib3styles.css" type="text/css" />
|
|
<link rel="Start" href="../documentation.html" type="text/html"
|
|
title="GNU C++ Standard Library" />
|
|
<link rel="Subsection" href="sgiexts.html" type="text/html" title="Extensions" />
|
|
<link rel="Bookmark" href="howto.html" type="text/html" title="Extensions" />
|
|
<link rel="Copyright" href="../17_intro/license.html" type="text/html" />
|
|
</head>
|
|
<body>
|
|
|
|
<h1 class="centered"><a name="top">SGI extensions to the library in
|
|
libstdc++-v3</a></h1>
|
|
|
|
<p>This page describes the extensions that SGI made to their version of the
|
|
STL subset of the Standard C++ Library. For a time we
|
|
<a href="../faq/index.html#5_3">tracked and imported changes and updates
|
|
from most of the SGI STL</a>, up through their (apparently) final release.
|
|
Their extensions were mostly preserved.
|
|
</p>
|
|
|
|
<p>They are listed according to the chapters of the library that they
|
|
extend (see <a href="../documentation.html#3">the chapter-specific notes</a>
|
|
for a description). Not every chapter may have extensions, and the
|
|
extensions may come and go. Also, this page is incomplete because the
|
|
author is pressed for time. Check back often; the latest change was on
|
|
$Date: 2003/04/16 17:02:47 $ (UTC).
|
|
</p>
|
|
|
|
<p>Descriptions range from the scanty to the verbose. You should also check
|
|
the <a href="../documentation.html#4">generated documentation</a> for notes
|
|
and comments, especially for entries marked with '*'. For more complete
|
|
doumentation, see the SGI website. For <em>really</em> complete
|
|
documentation, buy a copy of Matt Austern's book. *grin*
|
|
</p>
|
|
|
|
<p>Back to the <a href="howto.html">libstdc++-v3 extensions</a>.
|
|
</p>
|
|
|
|
|
|
<!-- ####################################################### -->
|
|
<hr />
|
|
<h3><a name="ch20">Chapter 20</a></h3>
|
|
<p>The <functional> header contains many additional functors and
|
|
helper functions, extending section 20.3. They are implemented in the
|
|
file stl_function.h:
|
|
</p>
|
|
<ul>
|
|
<li><code>identity_element</code> for addition and multiplication. * </li>
|
|
<li>The functor <code>identity</code>, whose <code>operator()</code>
|
|
returns the argument unchanged. * </li>
|
|
<li>Composition functors <code>unary_function</code> and
|
|
<code>binary_function</code>, and their helpers <code>compose1</code>
|
|
and <code>compose2</code>. * </li>
|
|
<li><code>select1st</code> and <code>select2nd</code>, to strip pairs. * </li>
|
|
<li><code>project1st</code> and <code>project2nd</code>. * </li>
|
|
<li>A set of functors/functions which always return the same result. They
|
|
are <code>constant_void_fun</code>, <code>constant_binary_fun</code>,
|
|
<code>constant_unary_fun</code>, <code>constant0</code>,
|
|
<code>constant1</code>, and <code>constant2</code>. * </li>
|
|
<li>The class <code>subtractive_rng</code>. * </li>
|
|
<li>mem_fun adaptor helpers <code>mem_fun1</code> and
|
|
<code>mem_fun1_ref</code> are provided for backwards compatibility. </li>
|
|
</ul>
|
|
<p>20.4.1 can use several different allocators; they are described on the
|
|
main extensions page.
|
|
</p>
|
|
<p>20.4.3 is extended with a special version of
|
|
<code>get_temporary_buffer</code> taking a second argument. The argument
|
|
is a pointer, which is ignored, but can be used to specify the template
|
|
type (instead of using explicit function template arguments like the
|
|
standard version does). That is, in addition to
|
|
</p>
|
|
<pre>
|
|
get_temporary_buffer<int>(5);</pre>
|
|
you can also use
|
|
<pre>
|
|
get_temporary_buffer(5, (int*)0);</pre>
|
|
<p>A class <code>temporary_buffer</code> is given in stl_tempbuf.h. *
|
|
</p>
|
|
<p>The specialized algorithms of section 20.4.4 are extended with
|
|
<code>uninitialized_copy_n</code>. *
|
|
</p>
|
|
<p>Return <a href="howto.html">to the main extensions page</a> or
|
|
<a href="http://gcc.gnu.org/libstdc++/">to the homepage</a>.
|
|
</p>
|
|
|
|
|
|
<hr />
|
|
<h3><a name="ch23">Chapter 23</a></h3>
|
|
<p>A few extensions and nods to backwards-compatibility have been made with
|
|
containers. Those dealing with older SGI-style allocators are dealt with
|
|
elsewhere. The remaining ones all deal with bits:
|
|
</p>
|
|
<p>The old pre-standard <code>bit_vector</code> class is present for
|
|
backwards compatibility. It is simply a typedef for the
|
|
<code>vector<bool></code> specialization.
|
|
</p>
|
|
<p>The <code>bitset</code> class has a number of extensions, described in the
|
|
rest of this item. First, we'll mention that this implementation of
|
|
<code>bitset<N></code> is specialized for cases where N number of
|
|
bits will fit into a single word of storage. If your choice of N is
|
|
within that range (<=32 on i686-pc-linux-gnu, for example), then all
|
|
of the operations will be faster.
|
|
</p>
|
|
<p>There are
|
|
versions of single-bit test, set, reset, and flip member functions which
|
|
do no range-checking. If we call them member functions of an instantiation
|
|
of "bitset<N>," then their names and signatures are:
|
|
</p>
|
|
<pre>
|
|
bitset<N>& _Unchecked_set (size_t pos);
|
|
bitset<N>& _Unchecked_set (size_t pos, int val);
|
|
bitset<N>& _Unchecked_reset (size_t pos);
|
|
bitset<N>& _Unchecked_flip (size_t pos);
|
|
bool _Unchecked_test (size_t pos);</pre>
|
|
<p>Note that these may in fact be removed in the future, although we have
|
|
no present plans to do so (and there doesn't seem to be any immediate
|
|
reason to).
|
|
</p>
|
|
<p>The semantics of member function <code>operator[]</code> are not specified
|
|
in the C++ standard. A long-standing defect report calls for sensible
|
|
obvious semantics, which are already implemented here: <code>op[]</code>
|
|
on a const bitset returns a bool, and for a non-const bitset returns a
|
|
<code>reference</code> (a nested type). However, this implementation does
|
|
no range-checking on the index argument, which is in keeping with other
|
|
containers' <code>op[]</code> requirements. The defect report's proposed
|
|
resolution calls for range-checking to be done. We'll just wait and see...
|
|
</p>
|
|
<p>Finally, two additional searching functions have been added. They return
|
|
the index of the first "on" bit, and the index of the first
|
|
"on" bit that is after <code>prev</code>, respectively:
|
|
</p>
|
|
<pre>
|
|
size_t _Find_first() const;
|
|
size_t _Find_next (size_t prev) const;</pre>
|
|
<p>The same caveat given for the _Unchecked_* functions applies here also.
|
|
</p>
|
|
<p>Return <a href="howto.html">to the main extensions page</a> or
|
|
<a href="http://gcc.gnu.org/libstdc++/">to the homepage</a>.
|
|
</p>
|
|
|
|
|
|
<hr />
|
|
<h3><a name="ch24">Chapter 24</a></h3>
|
|
<p>24.3.2 describes <code>struct iterator</code>, which didn't exist in the
|
|
original HP STL implementation (the language wasn't rich enough at the
|
|
time). For backwards compatibility, base classes are provided which
|
|
declare the same nested typedefs:
|
|
</p>
|
|
<ul>
|
|
<li>input_iterator</li>
|
|
<li>output_iterator</li>
|
|
<li>forward_iterator</li>
|
|
<li>bidirectional_iterator</li>
|
|
<li>random_access_iterator</li>
|
|
</ul>
|
|
<p>24.3.4 describes iterator operation <code>distance</code>, which takes
|
|
two iterators and returns a result. It is extended by another signature
|
|
which takes two iterators and a reference to a result. The result is
|
|
modified, and the function returns nothing.
|
|
</p>
|
|
<p>Return <a href="howto.html">to the main extensions page</a> or
|
|
<a href="http://gcc.gnu.org/libstdc++/">to the homepage</a>.
|
|
</p>
|
|
|
|
|
|
<hr />
|
|
<h3><a name="ch25">Chapter 25</a></h3>
|
|
<p>25.1.6 (count, count_if) is extended with two more versions of count
|
|
and count_if. The standard versions return their results. The
|
|
additional signatures return void, but take a final parameter by
|
|
reference to which they assign their results, e.g.,
|
|
</p>
|
|
<pre>
|
|
void count (first, last, value, n);</pre>
|
|
<p>25.2 (mutating algorithms) is extended with two families of signatures,
|
|
random_sample and random_sample_n.
|
|
</p>
|
|
<p>25.2.1 (copy) is extended with
|
|
</p>
|
|
<pre>
|
|
copy_n (_InputIter first, _Size count, _OutputIter result);</pre>
|
|
<p>which copies the first 'count' elements at 'first' into 'result'.
|
|
</p>
|
|
<p>25.3 (sorting 'n' heaps 'n' stuff) is extended with some helper
|
|
predicates. Look in the doxygen-generated pages for notes on these.
|
|
</p>
|
|
<ul>
|
|
<li><code>is_heap</code> tests whether or not a range is a heap.</li>
|
|
<li><code>is_sorted</code> tests whether or not a range is sorted in
|
|
nondescending order.</li>
|
|
</ul>
|
|
<p>25.3.8 (lexigraphical_compare) is extended with
|
|
</p>
|
|
<pre>
|
|
lexicographical_compare_3way(_InputIter1 first1, _InputIter1 last1,
|
|
_InputIter2 first2, _InputIter2 last2)</pre>
|
|
<p>which does... what?
|
|
</p>
|
|
<p>Return <a href="howto.html">to the main extensions page</a> or
|
|
<a href="http://gcc.gnu.org/libstdc++/">to the homepage</a>.
|
|
</p>
|
|
|
|
|
|
<hr />
|
|
<h3><a name="ch26">Chapter 26</a></h3>
|
|
<p>26.4, the generalized numeric operations such as accumulate, are extended
|
|
with the following functions:
|
|
</p>
|
|
<pre>
|
|
power (x, n);
|
|
power (x, n, moniod_operation);</pre>
|
|
<p>Returns, in FORTRAN syntax, "x ** n" where n>=0. In the
|
|
case of n == 0, returns the <a href="#ch20">identity element</a> for the
|
|
monoid operation. The two-argument signature uses multiplication (for
|
|
a true "power" implementation), but addition is supported as well.
|
|
The operation functor must be associative.
|
|
</p>
|
|
<p>The <code>iota</code> function wins the award for Extension With the
|
|
Coolest Name. It "assigns sequentially increasing values to a range.
|
|
That is, it assigns value to *first, value + 1 to *(first + 1) and so
|
|
on." Quoted from SGI documentation.
|
|
</p>
|
|
<pre>
|
|
void iota(_ForwardIter first, _ForwardIter last, _Tp value);</pre>
|
|
<p>Return <a href="howto.html">to the main extensions page</a> or
|
|
<a href="http://gcc.gnu.org/libstdc++/">to the homepage</a>.
|
|
</p>
|
|
|
|
|
|
<!-- ####################################################### -->
|
|
|
|
<hr />
|
|
<p class="fineprint"><em>
|
|
See <a href="../17_intro/license.html">license.html</a> for copying conditions.
|
|
Comments and suggestions are welcome, and may be sent to
|
|
<a href="mailto:libstdc++@gcc.gnu.org">the libstdc++ mailing list</a>.
|
|
</em></p>
|
|
|
|
|
|
</body>
|
|
</html>
|