1 # Check for stdbool.h that conforms to C99.
3 dnl Copyright (C) 2002-2006, 2009-2010 Free Software Foundation, Inc.
4 dnl This file is free software; the Free Software Foundation
5 dnl gives unlimited permission to copy and/or distribute it,
6 dnl with or without modifications, as long as this notice is preserved.
10 # Prepare for substituting <stdbool.h> if it is not supported.
12 AC_DEFUN([AM_STDBOOL_H],
14 AC_REQUIRE([AC_HEADER_STDBOOL])
16 # Define two additional variables used in the Makefile substitution.
18 if test "$ac_cv_header_stdbool_h" = yes; then
25 if test "$ac_cv_type__Bool" = yes; then
30 AC_SUBST([HAVE__BOOL])
33 # AM_STDBOOL_H will be renamed to gl_STDBOOL_H in the future.
34 AC_DEFUN([gl_STDBOOL_H], [AM_STDBOOL_H])
36 # This version of the macro is needed in autoconf <= 2.67. Autoconf has
37 # it built in since 2.60, but we want the tweaks from the 2.68 version
38 # to avoid rejecting clang due to relying on extensions.
40 AC_DEFUN([AC_HEADER_STDBOOL],
41 [AC_CACHE_CHECK([for stdbool.h that conforms to C99],
42 [ac_cv_header_stdbool_h],
47 "error: bool is not defined"
50 "error: false is not defined"
53 "error: false is not 0"
56 "error: true is not defined"
59 "error: true is not 1"
61 #ifndef __bool_true_false_are_defined
62 "error: __bool_true_false_are_defined is not defined"
65 struct s { _Bool s: 1; _Bool t; } s;
67 char a[true == 1 ? 1 : -1];
68 char b[false == 0 ? 1 : -1];
69 char c[__bool_true_false_are_defined == 1 ? 1 : -1];
70 char d[(bool) 0.5 == true ? 1 : -1];
72 char f[(_Bool) 0.0 == false ? 1 : -1];
74 char h[sizeof (_Bool)];
76 enum { j = false, k = true, l = false * true, m = true * 256 };
78 char o[sizeof n == m * sizeof n[0] ? 1 : -1];
79 char p[-1 - (_Bool) 0 < 0 && -1 - (bool) 0 < 0 ? 1 : -1];
81 /* Catch a bug in IBM AIX xlc compiler version 6.0.0.0
82 reported by James Lemley on 2005-10-05; see
83 http://lists.gnu.org/archive/html/bug-coreutils/2005-10/msg00086.html
84 This test is not quite right, since xlc is allowed to
85 reject this program, as the initializer for xlcbug is
86 not one of the forms that C requires support for.
87 However, doing the test right would require a run-time
88 test, and that would make cross-compilation harder.
89 Let us hope that IBM fixes the xlc bug, and also adds
90 support for this kind of constant expression. In the
91 meantime, this test will reject xlc, which is OK, since
92 our stdbool.h substitute should suffice. We also test
93 in test-stdbool.c to ensure nothing else messes up. */
94 char digs[] = "0123456789";
95 int xlcbug = 1 / (&(digs + 5)[-2 + (bool) 1] == &digs[4] ? 1 : 0);
97 /* Catch a bug in an HP-UX C compiler. See
98 http://gcc.gnu.org/ml/gcc-patches/2003-12/msg02303.html
99 http://lists.gnu.org/archive/html/bug-coreutils/2005-11/msg00161.html
107 /* Refer to every declared value, to avoid compiler optimizations. */
108 return (!a + !b + !c + !d + !e + !f + !g + !h + !i + !!j + !k + !!l
109 + !m + !n + !o + !p + !q + !pq);
111 [ac_cv_header_stdbool_h=yes],
112 [ac_cv_header_stdbool_h=no])])
113 AC_CHECK_TYPES([_Bool])
114 if test $ac_cv_header_stdbool_h = yes; then
115 AC_DEFINE([HAVE_STDBOOL_H], [1], [Define to 1 if stdbool.h conforms to C99.])