preprocessor/7263: __extension__ keyword doesn't suppress warning on LL or ULL constants

[Christian Ehrhardt]

The following reply was made to PR preprocessor/7263; it has been noted by GNATS.

From: "Christian Ehrhardt" <ehrhardt@mathematik.uni-ulm.de>
To: Neil Booth <neil@daikokuya.co.uk>
Cc: andrew@andypo.net, gcc-bugs@gcc.gnu.org, gcc-prs@gcc.gnu.org,
  nobody@gcc.gnu.org, gcc-gnats@gcc.gnu.org
Subject: Re: preprocessor/7263: __extension__ keyword doesn't suppress warning on LL or ULL constants
Date: Tue, 10 Dec 2002 11:36:37 +0100

 On Tue, Dec 10, 2002 at 12:22:56AM +0000, Neil Booth wrote:
 > ehrhardt@mathematik.uni-ulm.de wrote:-
 > 
 > >     I can confirm this on recent 3.3. The warning is from the preprocessor
 > >     where we don't know about __extension__. Maybe the fix is to just
 > >     document this. Anyway: Category changed to preprocessor and priority
 > >     raised to medium because this is technically a regression.
 > 
 > I think we just document __extension__ as only applying to non-CPP issues;
 > we can't reasonably expect CPP to interact with a parser in all situations
 > and under all future code changes.  I imagine we could enhance existing
 > code so that we don't have this problem in cases where it is the C front
 > end requesting the number interpretation, since it could easily pass a
 > "don't warn about foo" flag to cpplib.  However expecting cpplib to get
 > it right for #if is not reasonable, seeing as #if can occur between any
 > two tokens.
 
 The real problem seems to be that cpplib has its own copy of warning options
 in pfile->cpp_opts. The C parser disables the global pedantic flag while
 __extension__ is in effect. However, this change is not propagated into
 cpp_opts. If this was done we could just add the pedantic check in
 cppexp.c. However, neither do I see a clean way to propagate the global
 pedantic flag into cpp_opts nor to check the global flag from cpplib.
 
      regards   Christian
 
 -- 
 THAT'S ALL FOLKS!