[Bug libstdc++/6257] C-library symbols enter global namespace

["neroden at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>]

------- Comment #15 from neroden at gcc dot gnu dot org  2005-10-03 03:42 -------
So there's a problem with the multiple-include-protection in glibc!
We actually want to include the headers twice, potentially -- once when
included via <cstdio> et al, with everything in namespaces, and once when
included directly via <stdio.h> et al, with everything outside them.  They
actually shouldn't conflict because that's the whole *point* of putting stuff
in a namespace.

But we can't do this in any manner because they have multiple-include
protection which can't tell the difference.

I think this should be solved in glibc.  Feel free to forward this suggestion
and this code (which I donate to the public domain) to somewhere appropriate.

At the beginning of stdio.h, instead of:
#ifndef _STDIO_H
#define _STDIO_H
we would have:
#if   ( ( defined __cplusplus && defined _GLIBCPP_USE_NAMESPACES ) \
        && ! defined _STDIO_H_WITH_NAMESPACES ) \
   || ( (! defined __cplusplus || ! defined _GLIBCPP_USE_NAMESPACES )\
        && ! defined _STDIO_H )
#if defined __cplusplus && defined _GLIBCPP_USE_NAMESPACES
#  define _STDIO_H_WITH_NAMESPACES
#else
#  define _STDIO_H
#endif

For glibc, _GLIPCPP_USE_NAMESPACES could be defined in <cstdio> before the
inclusion of stdio.h and undefined afterwards.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=6257