include/attribute.h

   1 /* attribute.h - portability hacks for __attribute__ usage in other header files
   2
   3    Copyright (C) 2001  Russell Kroll <rkroll@exploits.org>
   4         2005    Arnaud Quette <arnaud.quette@free.fr>
   5         2020    Jim Klimov <jimklimov@gmail.com>
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 2 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program; if not, write to the Free Software
  19    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  20 */
  21
  22 #ifndef NUT_ATTRIBUTE_H_SEEN
  23 #define NUT_ATTRIBUTE_H_SEEN 1
  24
  25 /* To complicate matters, compilers with native support
  26  * for the keyword may expose or not expose it as a macro...
  27  * but for those that perform such courtesy, or are known
  28  * supporters, we can put up the flag. For others, someone
  29  * with those compilers should check and file PRs to NUT.
  30  */
  31 #if (!defined HAVE___ATTRIBUTE__) || (HAVE___ATTRIBUTE__ == 0)
  32 # if ( defined(__GNUC__) && ( __GNUC__ < 2 || (__GNUC__ == 2 && __GNUC_MINOR__ < 8) ) ) || ( defined(__STRICT_ANSI__) && __STRICT_ANSI__ )
  33 #  ifndef __attribute__
  34 #   define __attribute__(x)
  35 #  endif
  36 #  ifndef HAVE___ATTRIBUTE__
  37 #   define HAVE___ATTRIBUTE__ 0
  38 #  endif
  39 # else
  40 #  if defined(__clang__) || defined(__GNUC__) || defined(__SUNPRO_C)
  41 #   ifndef HAVE___ATTRIBUTE__
  42 #    define HAVE___ATTRIBUTE__ 1
  43 #   endif
  44 #  else
  45 #   ifndef HAVE___ATTRIBUTE__
  46 #    define HAVE___ATTRIBUTE__ 0
  47 #   endif
  48 #  endif
  49 # endif
  50 #endif
  51
  52 #if (!defined HAVE___ATTRIBUTE__) || (HAVE___ATTRIBUTE__ == 0)
  53 # ifdef HAVE___ATTRIBUTE__UNUSED_ARG
  54 #  undef HAVE___ATTRIBUTE__UNUSED_ARG
  55 # endif
  56 # ifdef HAVE___ATTRIBUTE__UNUSED_FUNC
  57 #  undef HAVE___ATTRIBUTE__UNUSED_FUNC
  58 # endif
  59 # ifdef HAVE___ATTRIBUTE__NORETURN
  60 #  undef HAVE___ATTRIBUTE__NORETURN
  61 # endif
  62 # ifdef HAVE___ATTRIBUTE__
  63 #  undef HAVE___ATTRIBUTE__
  64 # endif
  65 #endif
  66
  67 /* Other source files now can simply check for `ifdef HAVE___ATTRIBUTE__*`
  68  * as usual, and not bother about 0/1 values of the macro as well.
  69  */
  70
  71 #endif /* NUT_ATTRIBUTE_H_SEEN */