Use Gnulib ACL implementation, for benefit of Solaris etc.

[bpt/emacs.git] / m4 / extern-inline.m4

dnl 'extern inline' a la ISO C99.

dnl Copyright 2012-2013 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
dnl with or without modifications, as long as this notice is preserved.

AC_DEFUN([gl_EXTERN_INLINE],
[
  AH_VERBATIM([extern_inline],
[/* _GL_INLINE is a portable alternative to ISO C99 plain 'inline'.
   _GL_EXTERN_INLINE is a portable alternative to 'extern inline'.
   _GL_INLINE_HEADER_BEGIN contains useful stuff to put
     in an include file, before uses of _GL_INLINE.
     It suppresses GCC's bogus "no previous prototype for 'FOO'" diagnostic,
     when FOO is an inline function in the header; see
     <http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54113>.
   _GL_INLINE_HEADER_END contains useful stuff to put
     in the same include file, after uses of _GL_INLINE.

   Suppress extern inline with HP-UX cc, as it appears to be broken; see
   <http://lists.gnu.org/archive/html/bug-texinfo/2013-02/msg00030.html>.

   Suppress extern inline with Sun C in standards-conformance mode, as it
   mishandles inline functions that call each other.  E.g., for 'inline void f
   (void) { } inline void g (void) { f (); }', c99 incorrectly complains
   'reference to static identifier "f" in extern inline function'.
   This bug was observed with Sun C 5.12 SunOS_i386 2011/11/16.

   Suppress the use of extern inline on Apple's platforms, as Libc at least
   through Libc-825.26 (2013-04-09) is incompatible with it; see, e.g.,
   <http://lists.gnu.org/archive/html/bug-gnulib/2012-12/msg00023.html>.
   Perhaps Apple will fix this some day.  */
#if ((__GNUC__ \
      ? defined __GNUC_STDC_INLINE__ && __GNUC_STDC_INLINE__ \
      : (199901L <= __STDC_VERSION__ \
         && !defined __HP_cc \
         && !(defined __SUNPRO_C && __STDC__))) \
     && !defined __APPLE__)
# define _GL_INLINE inline
# define _GL_EXTERN_INLINE extern inline
#elif 2 < __GNUC__ + (7 <= __GNUC_MINOR__) && !defined __APPLE__
# if __GNUC_GNU_INLINE__
   /* __gnu_inline__ suppresses a GCC 4.2 diagnostic.  */
#  define _GL_INLINE extern inline __attribute__ ((__gnu_inline__))
# else
#  define _GL_INLINE extern inline
# endif
# define _GL_EXTERN_INLINE extern
#else
# define _GL_INLINE static _GL_UNUSED
# define _GL_EXTERN_INLINE static _GL_UNUSED
#endif

#if 4 < __GNUC__ + (6 <= __GNUC_MINOR__)
# if defined __GNUC_STDC_INLINE__ && __GNUC_STDC_INLINE__
#  define _GL_INLINE_HEADER_CONST_PRAGMA
# else
#  define _GL_INLINE_HEADER_CONST_PRAGMA \
     _Pragma ("GCC diagnostic ignored \"-Wsuggest-attribute=const\"")
# endif
# define _GL_INLINE_HEADER_BEGIN \
    _Pragma ("GCC diagnostic push") \
    _Pragma ("GCC diagnostic ignored \"-Wmissing-prototypes\"") \
    _Pragma ("GCC diagnostic ignored \"-Wmissing-declarations\"") \
    _GL_INLINE_HEADER_CONST_PRAGMA
# define _GL_INLINE_HEADER_END \
    _Pragma ("GCC diagnostic pop")
#else
# define _GL_INLINE_HEADER_BEGIN
# define _GL_INLINE_HEADER_END
#endif])
])