dnl Date: Sun, 26 Feb 2012 11:31:50 -0800

dnl From: Paul Eggert <eggert@cs.ucla.edu>

dnl To: arnold@skeeve.com

dnl CC: bug-grep@gnu.org

dnl Subject: Re: avoid gcc 4.6.2 'may be used before set' warnings in dfa.c

dnl 

dnl On 02/26/2012 01:18 AM, arnold@skeeve.com wrote:

dnl > It looks like I can just use the code as it is now in grep. I have asked

dnl > for compile failures and haven't gotten any.

dnl 

dnl Sure, but the gnulib support for this is better

dnl than what's in the dfa code.  It could be that

dnl your correspondents aren't using the less-common hosts

dnl or compiler warning options that gnulib is ported to.

dnl 

dnl In the long run stdnoreturn.h or _Noreturn is the way to go,

dnl since they're part of the C standard.

dnl 

dnl If you'd rather not create a separate file, how about if

dnl we change the dfa code to use _Noreturn instead of

dnl <stdnoreturn.h> and noreturn, and you can put the

dnl following into your configure.ac so that config.h

dnl defines _Noreturn the same way gnulib does:

AC_DEFUN([GAWK_AC_NORETURN],[

AH_VERBATIM([_Noreturn],

[/* The _Noreturn keyword of C11.  */

#ifndef _Noreturn

# if (3 <= __GNUC__ || (__GNUC__ == 2 && 8 <= __GNUC_MINOR__) \

      || 0x5110 <= __SUNPRO_C)

#  define _Noreturn __attribute__ ((__noreturn__))

# elif defined _MSC_VER && 1200 <= _MSC_VER

#  define _Noreturn __declspec (noreturn)

# else

#  define _Noreturn

# endif

#endif

])])