Re: glibc 2.1.1pre2 breaks libstdc++-v3 build

[Neil Booth <neil at daikokuya dot demon dot co dot uk>]

Joseph S. Myers wrote:-

> As this variadic macro is defined in a
> system header, I don't think -pedantic should complain about its uses.
> 
> #  define printf(fmt, args...) fprintf (stdout, fmt, ##args)
> 
> ...
> 
> printf("foo");

No.  I'm not playing games with where macros are defined - this has
been suggested before.  In a general macro expansion, it's extremely
non-trivial to know whether a token you're looking at comes from

a) another macro's expansion [recurse this]
b) macro arguments [recurse this]
c) the source file

and whether, for each of those above, it comes from

1) a system header
2) a non-system-header

Non-performance-degrading patches are welcome, though :-)

Neil.