[gcc r13-7164] libstdc++: Document libstdc++exp.a library for -fcontracts

[gcc r13-7164] libstdc++: Document libstdc++exp.a library for -fcontracts

[Jonathan Wakely]

https://gcc.gnu.org/g:adda0e288727eab5635d8df153f104021e0121d6

commit r13-7164-gadda0e288727eab5635d8df153f104021e0121d6
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Wed Apr 12 23:23:47 2023 +0100

    libstdc++: Document libstdc++exp.a library for -fcontracts
    
    libstdc++-v3/ChangeLog:
    
            * doc/xml/manual/using.xml: Document libstdc++exp.a library.
            * doc/html/*: Regenerate.

Diff:
---
 libstdc++-v3/doc/html/manual/using.html            |  3 +++
 .../doc/html/manual/using_dynamic_or_shared.html   | 17 ++++++++++----
 libstdc++-v3/doc/xml/manual/using.xml              | 27 ++++++++++++++++++----
 3 files changed, 39 insertions(+), 8 deletions(-)

diff --git a/libstdc++-v3/doc/html/manual/using.html b/libstdc++-v3/doc/html/manual/using.html
index f23325ebe97..eebb35da279 100644
--- a/libstdc++-v3/doc/html/manual/using.html
+++ b/libstdc++-v3/doc/html/manual/using.html
@@ -31,6 +31,9 @@
       </td></tr><tr><td align="left"><code class="literal">-lstdc++fs</code></td><td align="left">Linking to <code class="filename">libstdc++fs</code>
         is required for use of the Filesystem library extensions in
         <code class="filename">&lt;experimental/filesystem&gt;</code>.
+      </td></tr><tr><td align="left"><code class="literal">-lstdc++exp</code></td><td align="left">Linking to <code class="filename">libstdc++exp</code>
+        is required for use of the C++ Contracts extensions enabled by
+        <code class="literal">-fcontracts</code>.
       </td></tr><tr><td align="left"><code class="literal">-lstdc++_libbacktrace</code></td><td align="left">Until C++23 support is non-experimental, linking to
 	<code class="filename">libstdc++_libbacktrace.a</code>
 	is required for use of the C++23 type
diff --git a/libstdc++-v3/doc/html/manual/using_dynamic_or_shared.html b/libstdc++-v3/doc/html/manual/using_dynamic_or_shared.html
index 73d1f18485f..46ccbc55c33 100644
--- a/libstdc++-v3/doc/html/manual/using_dynamic_or_shared.html
+++ b/libstdc++-v3/doc/html/manual/using_dynamic_or_shared.html
@@ -136,12 +136,21 @@ A quick read of the relevant part of the GCC
       no shared library for it. To use the library you should include
       <code class="filename">&lt;experimental/filesystem&gt;</code>
       and link with <code class="option">-lstdc++fs</code>. The library implementation
-      is incomplete on non-POSIX platforms, specifically Windows support is
-      rudimentary.
+      is incomplete on non-POSIX platforms, specifically Windows is only
+      partially supported.
     </p><p>
-      Due to the experimental nature of the Filesystem library the usual
+      GCC 13 includes an implementation of the C++ Contracts library defined by
+      <a class="link" href="https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2019/p1429r3.pdf" target="_top">P1429R3</a>.
+      Because this is an experimental extension, not part of the C++ standard,
+      it is implemented in a separate library,
+      <code class="filename">libstdc++exp.a</code>, and there is
+      no shared library for it. To use the library you should include
+      <code class="filename">&lt;experimental/contract&gt;</code>
+      and link with <code class="option">-lstdc++exp</code>.
+    </p><p>
+      Due to the experimental nature of these libraries the usual
       guarantees about ABI stability and backwards compatibility do not apply
-      to it. There is no guarantee that the components in any
+      to them. There is no guarantee that the components in any
       <code class="filename">&lt;experimental/xxx&gt;</code>
       header will remain compatible between different GCC releases.
     </p></div></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="using_namespaces.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="using.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="using_concurrency.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">Namespaces </td><td width="20%" align="center"><a accesskey="h" href="../index.html">Home</a></td><td width="40%" align="right" valign="top"> Concurrency</td></tr></table></div></body></html>
\ No newline at end of file
diff --git a/libstdc++-v3/doc/xml/manual/using.xml b/libstdc++-v3/doc/xml/manual/using.xml
index 7f011a6d931..3a507fc1671 100644
--- a/libstdc++-v3/doc/xml/manual/using.xml
+++ b/libstdc++-v3/doc/xml/manual/using.xml
@@ -108,6 +108,14 @@
       </entry>
     </row>
 
+    <row>
+      <entry><literal>-lstdc++exp</literal></entry>
+      <entry>Linking to <filename class="libraryfile">libstdc++exp</filename>
+        is required for use of the C++ Contracts extensions enabled by
+        <literal>-fcontracts</literal>.
+      </entry>
+    </row>
+
     <row>
       <entry><literal>-lstdc++_libbacktrace</literal></entry>
       <entry>Until C++23 support is non-experimental, linking to
@@ -1700,14 +1708,25 @@ A quick read of the relevant part of the GCC
       no shared library for it. To use the library you should include
       <filename class="headerfile">&lt;experimental/filesystem&gt;</filename>
       and link with <option>-lstdc++fs</option>. The library implementation
-      is incomplete on non-POSIX platforms, specifically Windows support is
-      rudimentary.
+      is incomplete on non-POSIX platforms, specifically Windows is only
+      partially supported.
+    </para>
+
+    <para>
+      GCC 13 includes an implementation of the C++ Contracts library defined by
+      <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2019/p1429r3.pdf">P1429R3</link>.
+      Because this is an experimental extension, not part of the C++ standard,
+      it is implemented in a separate library,
+      <filename class="libraryfile">libstdc++exp.a</filename>, and there is
+      no shared library for it. To use the library you should include
+      <filename class="headerfile">&lt;experimental/contract&gt;</filename>
+      and link with <option>-lstdc++exp</option>.
     </para>
 
     <para>
-      Due to the experimental nature of the Filesystem library the usual
+      Due to the experimental nature of these libraries the usual
       guarantees about ABI stability and backwards compatibility do not apply
-      to it. There is no guarantee that the components in any
+      to them. There is no guarantee that the components in any
       <filename class="headerfile">&lt;experimental/xxx&gt;</filename>
       header will remain compatible between different GCC releases.
     </para>