http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54130
--- Comment #7 from joseph at codesourcery dot com <joseph at codesourcery dot com> 2012-07-31 22:12:51 UTC --- On Tue, 31 Jul 2012, glisse at gcc dot gnu.org wrote: > http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54130 > > --- Comment #6 from Marc Glisse <glisse at gcc dot gnu.org> 2012-07-31 > 20:13:38 UTC --- > (In reply to comment #5) > > If your system headers declare isnan with bool return type I advise making > > fixincludes fix them. > > But the C++ standard requires a bool return type, using fixinclude to replace > a > standard prototype with a non-standard one is strange... C++ may also require functions rather than macros in various cases. It's the job of the libstdc++ headers, provided by GCC, to provide a (probably inline) isnan function meeting the C++ requirements, replacing the C library's macro when building for C++. Likewise all the other cases where C++ and C requirements for standard headers differ: the fix is in headers in one form or another rather than built in to the compiler.
