xref: /netbsd-src/external/gpl2/diffutils/dist/m4/stdbool.m4 (revision 75f6d617e282811cb173c2ccfbf5df0dd71f7045)
1# Check for stdbool.h that conforms to C99.
2
3# Copyright (C) 2002 Free Software Foundation, Inc.
4
5# This program is free software; you can redistribute it and/or modify
6# it under the terms of the GNU General Public License as published by
7# the Free Software Foundation; either version 2, or (at your option)
8# any later version.
9
10# This program is distributed in the hope that it will be useful,
11# but WITHOUT ANY WARRANTY; without even the implied warranty of
12# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13# GNU General Public License for more details.
14
15# You should have received a copy of the GNU General Public License
16# along with this program; if not, write to the Free Software
17# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
18# 02111-1307, USA.
19
20AC_DEFUN([AC_HEADER_STDBOOL],
21  [AC_CACHE_CHECK([for stdbool.h that conforms to C99],
22     [ac_cv_header_stdbool_h],
23     [AC_TRY_COMPILE(
24	[
25	  #include <stdbool.h>
26	  #ifndef bool
27	   "error: bool is not defined"
28	  #endif
29	  #ifndef false
30	   "error: false is not defined"
31	  #endif
32	  #ifndef true
33	   "error: false is not defined"
34	  #endif
35	  #ifndef __bool_true_false_are_defined
36	   "error: __bool_true_false_are_defined is not defined"
37	  #endif
38
39	  struct s { _Bool s: 1; _Bool t; } s;
40
41	  char a[true == 1 ? 1 : -1];
42	  char b[false == 0 ? 1 : -1];
43	  char c[__bool_true_false_are_defined == 1 ? 1 : -1];
44	  char d[(bool) -0.5 == true ? 1 : -1];
45	  char e[(bool) &s == true ? 1 : -1];
46	  char f[(_Bool) -0.0 == false ? 1 : -1];
47	  char g[true];
48	  char h[sizeof (_Bool)];
49	  char i[sizeof s.t];
50	],
51	[ return !a + !b + !c + !d + !e + !f + !g + !h + !i; ],
52	[ac_cv_header_stdbool_h=yes],
53	[ac_cv_header_stdbool_h=no])])
54   if test $ac_cv_header_stdbool_h = yes; then
55     AC_DEFINE(HAVE_STDBOOL_H, 1, [Define to 1 if stdbool.h conforms to C99.])
56   fi])
57