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PR69699 document why __GLIBCXX__ macro is useless

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PR libstdc++/69699
	* doc/xml/manual/abi.xml (abi.versioning.history): Explain why the
	_GLIBCXX__ macro is not useful. Remove redundant date information
	and link to the GCC release timeline.
	(abi.versioning.active): Move partial sentence into the previous
	paragraph.
	* doc/html/*: Regenerate.

From-SVN: r244532
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Jonathan Wakely 2017-01-17 15:26:11 +00:00 committed by Jonathan Wakely
parent 04c872aae4
commit c6b8b5e4d3
3 changed files with 66 additions and 46 deletions
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8
libstdc++-v3/ChangeLog
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@ -1,5 +1,13 @@
2017-01-17 Jonathan Wakely <jwakely@redhat.com>
PR libstdc++/69699
* doc/xml/manual/abi.xml (abi.versioning.history): Explain why the
_GLIBCXX__ macro is not useful. Remove redundant date information
and link to the GCC release timeline.
(abi.versioning.active): Move partial sentence into the previous
paragraph.
* doc/html/*: Regenerate.
PR libstdc++/79114
* libsupc++/nested_exception.h (throw_with_nested): Use decay instead
of remove_reference.

32
libstdc++-v3/doc/html/manual/abi.html
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@ -153,12 +153,33 @@ compatible.
was released, in compressed ISO date format, as an unsigned long.
</p><p>
This macro is defined in the file "c++config" in the
"libstdc++-v3/include/bits" directory. (Up to GCC 4.1.0, it was
changed every night by an automated script. Since GCC 4.1.0, it is
the same value as gcc/DATESTAMP.)
"libstdc++-v3/include/bits" directory. Up to GCC 4.1.0, it was
changed every night by an automated script. Since GCC 4.1.0 it is set
during configuration to the same value as
<code class="filename">gcc/DATESTAMP</code>, so for an official release its value
is the same as the date of the release, which is given in the <a class="link" href="https://gcc.gnu.org/develop.html#timeline" target="_top">GCC Release
Timeline</a>.
</p><p>
This macro is not useful for determining whether a particular feature is
supported by the version of libstdc++ you are using. The date of a release
might be after a feature was added to the development trunk, but the
release could be from an older branch. For example, in the 5.4.0 release
the macro has the value 20160603 which is greater than the 20160427 value
of the macro in the 6.1.0 release, but there are features supported in the
6.1.0 release that are not supported in 5.4.0 release.
You also can't test for the the exact values listed below to try and
identify a release, because a snapshot taken from the gcc-5-branch on
2016-04-27 would have the same value for the macro as the 6.1.0 release
despite being a different version.
Many GNU/Linux distributions build their GCC packages from snapshots, so
the macro can have dates that doesn't correspond to official releases.
</p><p>
It is versioned as follows:
</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>GCC 3.0.0: 20010615</p></li><li class="listitem"><p>GCC 3.0.1: 20010819</p></li><li class="listitem"><p>GCC 3.0.2: 20011023</p></li><li class="listitem"><p>GCC 3.0.3: 20011220</p></li><li class="listitem"><p>GCC 3.0.4: 20020220</p></li><li class="listitem"><p>GCC 3.1.0: 20020514</p></li><li class="listitem"><p>GCC 3.1.1: 20020725</p></li><li class="listitem"><p>GCC 3.2.0: 20020814</p></li><li class="listitem"><p>GCC 3.2.1: 20021119</p></li><li class="listitem"><p>GCC 3.2.2: 20030205</p></li><li class="listitem"><p>GCC 3.2.3: 20030422</p></li><li class="listitem"><p>GCC 3.3.0: 20030513</p></li><li class="listitem"><p>GCC 3.3.1: 20030804</p></li><li class="listitem"><p>GCC 3.3.2: 20031016</p></li><li class="listitem"><p>GCC 3.3.3: 20040214</p></li><li class="listitem"><p>GCC 3.4.0: 20040419</p></li><li class="listitem"><p>GCC 3.4.1: 20040701</p></li><li class="listitem"><p>GCC 3.4.2: 20040906</p></li><li class="listitem"><p>GCC 3.4.3: 20041105</p></li><li class="listitem"><p>GCC 3.4.4: 20050519</p></li><li class="listitem"><p>GCC 3.4.5: 20051201</p></li><li class="listitem"><p>GCC 3.4.6: 20060306</p></li><li class="listitem"><p>GCC 4.0.0: 20050421</p></li><li class="listitem"><p>GCC 4.0.1: 20050707</p></li><li class="listitem"><p>GCC 4.0.2: 20050921</p></li><li class="listitem"><p>GCC 4.0.3: 20060309</p></li><li class="listitem"><p>GCC 4.1.0: 20060228</p></li><li class="listitem"><p>GCC 4.1.1: 20060524</p></li><li class="listitem"><p>GCC 4.1.2: 20070214</p></li><li class="listitem"><p>GCC 4.2.0: 20070514</p></li><li class="listitem"><p>GCC 4.2.1: 20070719</p></li><li class="listitem"><p>GCC 4.2.2: 20071007</p></li><li class="listitem"><p>GCC 4.2.3: 20080201</p></li><li class="listitem"><p>GCC 4.2.4: 20080519</p></li><li class="listitem"><p>GCC 4.3.0: 20080306</p></li><li class="listitem"><p>GCC 4.3.1: 20080606</p></li><li class="listitem"><p>GCC 4.3.2: 20080827</p></li><li class="listitem"><p>GCC 4.3.3: 20090124</p></li><li class="listitem"><p>GCC 4.3.4: 20090804</p></li><li class="listitem"><p>GCC 4.3.5: 20100522</p></li><li class="listitem"><p>GCC 4.3.6: 20110627</p></li><li class="listitem"><p>GCC 4.4.0: 20090421</p></li><li class="listitem"><p>GCC 4.4.1: 20090722</p></li><li class="listitem"><p>GCC 4.4.2: 20091015</p></li><li class="listitem"><p>GCC 4.4.3: 20100121</p></li><li class="listitem"><p>GCC 4.4.4: 20100429</p></li><li class="listitem"><p>GCC 4.4.5: 20101001</p></li><li class="listitem"><p>GCC 4.4.6: 20110416</p></li><li class="listitem"><p>GCC 4.4.7: 20120313</p></li><li class="listitem"><p>GCC 4.5.0: 20100414</p></li><li class="listitem"><p>GCC 4.5.1: 20100731</p></li><li class="listitem"><p>GCC 4.5.2: 20101216</p></li><li class="listitem"><p>GCC 4.5.3: 20110428</p></li><li class="listitem"><p>GCC 4.5.4: 20120702</p></li><li class="listitem"><p>GCC 4.6.0: 20110325</p></li><li class="listitem"><p>GCC 4.6.1: 20110627</p></li><li class="listitem"><p>GCC 4.6.2: 20111026</p></li><li class="listitem"><p>GCC 4.6.3: 20120301</p></li><li class="listitem"><p>GCC 4.7.0: 20120322</p></li><li class="listitem"><p>GCC 4.7.1: 20120614</p></li><li class="listitem"><p>GCC 4.7.2: 20120920</p></li></ul></div><p></p></li><li class="listitem"><p>
</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>GCC 3.0.0: 20010615</p></li><li class="listitem"><p>GCC 3.0.1: 20010819</p></li><li class="listitem"><p>GCC 3.0.2: 20011023</p></li><li class="listitem"><p>GCC 3.0.3: 20011220</p></li><li class="listitem"><p>GCC 3.0.4: 20020220</p></li><li class="listitem"><p>GCC 3.1.0: 20020514</p></li><li class="listitem"><p>GCC 3.1.1: 20020725</p></li><li class="listitem"><p>GCC 3.2.0: 20020814</p></li><li class="listitem"><p>GCC 3.2.1: 20021119</p></li><li class="listitem"><p>GCC 3.2.2: 20030205</p></li><li class="listitem"><p>GCC 3.2.3: 20030422</p></li><li class="listitem"><p>GCC 3.3.0: 20030513</p></li><li class="listitem"><p>GCC 3.3.1: 20030804</p></li><li class="listitem"><p>GCC 3.3.2: 20031016</p></li><li class="listitem"><p>GCC 3.3.3: 20040214</p></li><li class="listitem"><p>GCC 3.4.0: 20040419</p></li><li class="listitem"><p>GCC 3.4.1: 20040701</p></li><li class="listitem"><p>GCC 3.4.2: 20040906</p></li><li class="listitem"><p>GCC 3.4.3: 20041105</p></li><li class="listitem"><p>GCC 3.4.4: 20050519</p></li><li class="listitem"><p>GCC 3.4.5: 20051201</p></li><li class="listitem"><p>GCC 3.4.6: 20060306</p></li><li class="listitem"><p>GCC 4.0.0: 20050421</p></li><li class="listitem"><p>GCC 4.0.1: 20050707</p></li><li class="listitem"><p>GCC 4.0.2: 20050921</p></li><li class="listitem"><p>GCC 4.0.3: 20060309</p></li><li class="listitem"><p>
GCC 4.1.0 and later: the GCC release date, as shown in the
<a class="link" href="https://gcc.gnu.org/develop.html#timeline" target="_top">GCC
Release Timeline</a>
</p></li></ul></div><p></p></li><li class="listitem"><p>
Incremental bumping of a library pre-defined macro,
_GLIBCPP_VERSION. This macro is defined as the released version of
the library, as a string literal. This is only implemented in
@ -226,13 +247,12 @@ compatible.
</p></div><div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="abi.versioning.active"></a>Checking Active</h4></div></div></div><p>
When the GNU C++ library is being built with symbol versioning
on, you should see the following at configure time for
libstdc++:
libstdc++ (showing either 'gnu' or another of the supported styles):
</p><pre class="screen">
<code class="computeroutput">
checking versioning on shared library symbols... gnu
</code>
</pre><p>
or another of the supported styles.
If you don't see this line in the configure output, or if this line
appears but the last word is 'no', then you are out of luck.
</p><p>

72
libstdc++-v3/doc/xml/manual/abi.xml
View File

@ -393,10 +393,32 @@ compatible.
<para>
This macro is defined in the file "c++config" in the
"libstdc++-v3/include/bits" directory. (Up to GCC 4.1.0, it was
changed every night by an automated script. Since GCC 4.1.0, it is
the same value as gcc/DATESTAMP.)
"libstdc++-v3/include/bits" directory. Up to GCC 4.1.0, it was
changed every night by an automated script. Since GCC 4.1.0 it is set
during configuration to the same value as
<filename>gcc/DATESTAMP</filename>, so for an official release its value
is the same as the date of the release, which is given in the <link
xmlns:xlink="http://www.w3.org/1999/xlink"
xlink:href="https://gcc.gnu.org/develop.html#timeline">GCC Release
Timeline</link>.
</para>
<para>
This macro is not useful for determining whether a particular feature is
supported by the version of libstdc++ you are using. The date of a release
might be after a feature was added to the development trunk, but the
release could be from an older branch. For example, in the 5.4.0 release
the macro has the value 20160603 which is greater than the 20160427 value
of the macro in the 6.1.0 release, but there are features supported in the
6.1.0 release that are not supported in 5.4.0 release.
You also can't test for the the exact values listed below to try and
identify a release, because a snapshot taken from the gcc-5-branch on
2016-04-27 would have the same value for the macro as the 6.1.0 release
despite being a different version.
Many GNU/Linux distributions build their GCC packages from snapshots, so
the macro can have dates that doesn't correspond to official releases.
</para>
<para>
It is versioned as follows:
</para>
@ -427,41 +449,12 @@ compatible.
<listitem><para>GCC 4.0.1: 20050707</para></listitem>
<listitem><para>GCC 4.0.2: 20050921</para></listitem>
<listitem><para>GCC 4.0.3: 20060309</para></listitem>
<listitem><para>GCC 4.1.0: 20060228</para></listitem>
<listitem><para>GCC 4.1.1: 20060524</para></listitem>
<listitem><para>GCC 4.1.2: 20070214</para></listitem>
<listitem><para>GCC 4.2.0: 20070514</para></listitem>
<listitem><para>GCC 4.2.1: 20070719</para></listitem>
<listitem><para>GCC 4.2.2: 20071007</para></listitem>
<listitem><para>GCC 4.2.3: 20080201</para></listitem>
<listitem><para>GCC 4.2.4: 20080519</para></listitem>
<listitem><para>GCC 4.3.0: 20080306</para></listitem>
<listitem><para>GCC 4.3.1: 20080606</para></listitem>
<listitem><para>GCC 4.3.2: 20080827</para></listitem>
<listitem><para>GCC 4.3.3: 20090124</para></listitem>
<listitem><para>GCC 4.3.4: 20090804</para></listitem>
<listitem><para>GCC 4.3.5: 20100522</para></listitem>
<listitem><para>GCC 4.3.6: 20110627</para></listitem>
<listitem><para>GCC 4.4.0: 20090421</para></listitem>
<listitem><para>GCC 4.4.1: 20090722</para></listitem>
<listitem><para>GCC 4.4.2: 20091015</para></listitem>
<listitem><para>GCC 4.4.3: 20100121</para></listitem>
<listitem><para>GCC 4.4.4: 20100429</para></listitem>
<listitem><para>GCC 4.4.5: 20101001</para></listitem>
<listitem><para>GCC 4.4.6: 20110416</para></listitem>
<listitem><para>GCC 4.4.7: 20120313</para></listitem>
<listitem><para>GCC 4.5.0: 20100414</para></listitem>
<listitem><para>GCC 4.5.1: 20100731</para></listitem>
<listitem><para>GCC 4.5.2: 20101216</para></listitem>
<listitem><para>GCC 4.5.3: 20110428</para></listitem>
<listitem><para>GCC 4.5.4: 20120702</para></listitem>
<listitem><para>GCC 4.6.0: 20110325</para></listitem>
<listitem><para>GCC 4.6.1: 20110627</para></listitem>
<listitem><para>GCC 4.6.2: 20111026</para></listitem>
<listitem><para>GCC 4.6.3: 20120301</para></listitem>
<listitem><para>GCC 4.7.0: 20120322</para></listitem>
<listitem><para>GCC 4.7.1: 20120614</para></listitem>
<listitem><para>GCC 4.7.2: 20120920</para></listitem>
<listitem><para>
GCC 4.1.0 and later: the GCC release date, as shown in the
<link xmlns:xlink="http://www.w3.org/1999/xlink"
xlink:href="https://gcc.gnu.org/develop.html#timeline">GCC
Release Timeline</link>
</para></listitem>
</itemizedlist>
<para/>
</listitem>
@ -619,7 +612,7 @@ compatible.
<para>
When the GNU C++ library is being built with symbol versioning
on, you should see the following at configure time for
libstdc++:
libstdc++ (showing either 'gnu' or another of the supported styles):
</para>
<screen>
@ -629,7 +622,6 @@ compatible.
</screen>
<para>
or another of the supported styles.
If you don't see this line in the configure output, or if this line
appears but the last word is 'no', then you are out of luck.
</para>