[gcc r14-55] libstdc++: Adjust uses of null pointer constants in docs

[Jonathan Wakely]

https://gcc.gnu.org/g:b153f4e4caeae05a6bcb74c200031f9060139d08

commit r14-55-gb153f4e4caeae05a6bcb74c200031f9060139d08
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Wed Apr 19 00:07:36 2023 +0100

    libstdc++: Adjust uses of null pointer constants in docs
    
    libstdc++-v3/ChangeLog:
    
            * doc/xml/manual/extensions.xml: Fix example to declare and
            qualify std::free, and use NULL instead of 0.
            * doc/html/manual/ext_demangling.html: Regenerate.
            * libsupc++/cxxabi.h: Adjust doxygen comments.

Diff:
---
 libstdc++-v3/doc/html/manual/ext_demangling.html | 8 +++-----
 libstdc++-v3/doc/xml/manual/extensions.xml       | 8 +++-----
 libstdc++-v3/libsupc++/cxxabi.h                  | 4 ++--
 3 files changed, 8 insertions(+), 12 deletions(-)

diff --git a/libstdc++-v3/doc/html/manual/ext_demangling.html b/libstdc++-v3/doc/html/manual/ext_demangling.html
index 028ec71d8c8..1e7cdda8326 100644
--- a/libstdc++-v3/doc/html/manual/ext_demangling.html
+++ b/libstdc++-v3/doc/html/manual/ext_demangling.html
@@ -26,6 +26,7 @@
   </p><pre class="programlisting">
 #include <exception>
 #include <iostream>
+#include <cstdlib>
 #include <cxxabi.h>
 
 struct empty { };
@@ -33,7 +34,6 @@ struct empty { };
 template <typename T, int N>
   struct bar { };
 
-
 int main()
 {
   int     status;
@@ -43,11 +43,9 @@ int main()
   bar<empty,17>          u;
   const std::type_info  &ti = typeid(u);
 
-  realname = abi::__cxa_demangle(ti.name(), 0, 0, &status);
+  realname = abi::__cxa_demangle(ti.name(), NULL, NULL, &status);
   std::cout << ti.name() << "\t=> " << realname << "\t: " << status << '\n';
-  free(realname);
-
-  return 0;
+  std::free(realname);
 }
    </pre><p>
      This prints
diff --git a/libstdc++-v3/doc/xml/manual/extensions.xml b/libstdc++-v3/doc/xml/manual/extensions.xml
index 196b55d8347..daa98f5cba7 100644
--- a/libstdc++-v3/doc/xml/manual/extensions.xml
+++ b/libstdc++-v3/doc/xml/manual/extensions.xml
@@ -521,6 +521,7 @@ get_temporary_buffer(5, (int*)0);
    <programlisting>
 #include <exception>
 #include <iostream>
+#include <cstdlib>
 #include <cxxabi.h>
 
 struct empty { };
@@ -528,7 +529,6 @@ struct empty { };
 template <typename T, int N>
   struct bar { };
 
-
 int main()
 {
   int     status;
@@ -538,11 +538,9 @@ int main()
   bar<empty,17>          u;
   const std::type_info  &ti = typeid(u);
 
-  realname = abi::__cxa_demangle(ti.name(), 0, 0, &status);
+  realname = abi::__cxa_demangle(ti.name(), NULL, NULL, &status);
   std::cout << ti.name() << "\t=> " << realname << "\t: " << status << '\n';
-  free(realname);
-
-  return 0;
+  std::free(realname);
 }
    </programlisting>
    <para>
diff --git a/libstdc++-v3/libsupc++/cxxabi.h b/libstdc++-v3/libsupc++/cxxabi.h
index 10179bc0a0d..ac0637b0343 100644
--- a/libstdc++-v3/libsupc++/cxxabi.h
+++ b/libstdc++-v3/libsupc++/cxxabi.h
@@ -169,7 +169,7 @@ namespace __cxxabiv1
    *  @param __output_buffer A region of memory, allocated with
    *  malloc, of @a *__length bytes, into which the demangled name is
    *  stored.  If @a __output_buffer is not long enough, it is
-   *  expanded using realloc.  @a __output_buffer may instead be NULL;
+   *  expanded using realloc.  @a __output_buffer may instead be null;
    *  in that case, the demangled name is placed in a region of memory
    *  allocated with malloc.
    *
@@ -184,7 +184,7 @@ namespace __cxxabiv1
    *  -3: One of the arguments is invalid.
    *
    *  @return A pointer to the start of the NUL-terminated demangled
-   *  name, or NULL if the demangling fails.  The caller is
+   *  name, or a null pointer if the demangling fails.  The caller is
    *  responsible for deallocating this memory using @c free.
    *
    *  The demangling is performed using the C++ ABI mangling rules,