c_cpp/etc/calc/have_unused.c

   1 /*
   2  * have_unused - Determine if we want or can support the unused attribute
   3  *
   4  * Copyright (C) 2004  Landon Curt Noll
   5  *
   6  * Calc is open software; you can redistribute it and/or modify it under
   7  * the terms of the version 2.1 of the GNU Lesser General Public License
   8  * as published by the Free Software Foundation.
   9  *
  10  * Calc is distributed in the hope that it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  12  * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General
  13  * Public License for more details.
  14  *
  15  * A copy of version 2.1 of the GNU Lesser General Public License is
  16  * distributed with calc under the filename COPYING-LGPL.  You should have
  17  * received a copy with calc; if not, write to Free Software Foundation, Inc.
  18  * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  19  *
  20  * @(#) $Revision: 30.1 $
  21  * @(#) $Id: have_unused.c,v 30.1 2007/03/16 11:09:46 chongo Exp $
  22  * @(#) $Source: /usr/local/src/bin/calc/RCS/have_unused.c,v $
  23  *
  24  * Under source code control:   2004/02/22 22:36:10
  25  * File existed as early as:    2004
  26  *
  27  * chongo <was here> /\oo/\     http://www.isthe.com/chongo/
  28  * Share and enjoy!  :-)        http://www.isthe.com/chongo/tech/comp/calc/
  29  */
  30
  31 /*
  32  * usage:
  33  *      have_unused
  34  *
  35  * Not all compilers support the unused attribute, so this may not compile
  36  * on your system.
  37  *
  38  * This prog outputs several defines:
  39  *
  40  *      HAVE_UNUSED
  41  *              defined ==> ok to use unused
  42  *              undefined ==> do not use unused
  43  *
  44  *      UNUSED
  45  *              unused ==> use unused
  46  *              (nothing) ==> unused not used
  47  */
  48
  49
  50 #include <stdio.h>
  51
  52 #if !defined(HAVE_NO_UNUSED)
  53
  54 /* make sure that we can use the __attribute__((unused)) in #define's */
  55 #undef UNUSED
  56 #define UNUSED __attribute__((unused))
  57
  58 /*
  59  * unused_str - a function with an unused argument
  60  */
  61 static char *
  62 unused_str(char UNUSED *str)
  63 {
  64     return "__attribute__((unused))";
  65 }
  66
  67 #endif /* !HAVE_NO_UNUSED */
  68
  69
  70 int
  71 main(void)
  72 {
  73 #if defined(HAVE_NO_UNUSED)
  74
  75         printf("#undef HAVE_UNUSED /* no */\n");
  76         printf("#undef UNUSED\n");
  77         printf("#define UNUSED /* no */\n");
  78
  79 #else /* HAVE_NO_UNUSED */
  80
  81         printf("#define HAVE_UNUSED /* yes */\n");
  82         printf("#undef UNUSED\n");
  83         printf("#define UNUSED %s /* yes */\n", unused_str(NULL));
  84
  85 #endif /* HAVE_NO_UNUSED */
  86
  87         /* exit(0); */
  88         return 0;
  89 }