+2002-11-28 Jonathan Wakely <redi@gcc.gnu.org>
+ * docs/html/faq/index.html: Add tip about a namespace for extensions.
+
2002-11-28 Paolo Carlini <pcarlini@unitus.it>
Nathan Myers <ncm@cantrip.org>
that of other headers whose directories are not searched directly,
e.g., <code><sys/stat.h></code>, <code><X11/Xlib.h></code>.
</p>
+
+ <p>The extensions are no longer in the global or <code>std</code>
+ namespaces, instead they are declared in the <code>__gnu_cxx</code>
+ namespace. For maximum portability, consider defining a namespace
+ alias to use to talk about extensions, e.g.:
+ </p>
+ <pre>
+ #ifdef __GNUC__
+ #if __GNUC__ < 3
+ #include <hash_map.h>
+ namespace Sgi { using ::hash_map; }; // inherit globals
+ #else
+ #include <ext/hash_map>
+ #if __GNUC_MINOR__ == 0
+ namespace Sgi = std; // GCC 3.0
+ #else
+ namespace Sgi = ::__gnu_cxx; // GCC 3.1 and later
+ #endif
+ #endif
+ #else // ... there are other compilers, right?
+ namespace Sgi = std;
+ #endif
+
+ Sgi::hash_map<int,int> my_map; </pre>
+ <p>This is a bit cleaner than defining typedefs for all the
+ instantiations you might need.
+ </p>
+
<p>Extensions to the library have
<a href="../ext/howto.html">their own page</a>.
</p>