[Bug c/51437] GCC should warn on the use of reserved identifier/macro names

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

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51437

--- Comment #13 from Josh Triplett <josh at joshtriplett dot org> 2012-02-19 18:56:28 UTC ---
(In reply to comment #11)
> (In reply to comment #10)
> > (In reply to comment #9)
> > > (Some of the other reserved identifier categories, such as E[A-Z0-9].*,
> > > is[a-z].*, to[a-z].*, and mem[a-z].* should go under some separate, more
> > > pedantic warning option.)
> > 
> > I don't see why this should happen at all. There's nothing special about these
> > general names?
> 
> See comment #3, they are reserved in C99 Â7.26 "Future library directions"
> (although those patterns aren't quite right).

I wrote those patterns based on C11 section 7.30 "Future library directions". 
7.30.3 says "Macros that begin with E and a digit or E and an uppercase letter
may be added to the declarations in the <errno.h> header.".  7.30.2 says
"Function names that begin with either is or to, and a lowercase letter may be
added to the declarations in the <ctype.h> header."; 7.30.12 also reserves
those two for <wctype.h>.  7.30.11 says "Function names that begin with str,
mem, or wcs and a lowercase letter may be added to the declarations in the
<string.h> header."  AFAICT, those reservations match the regexes I gave.