1# Check for stdbool.h that conforms to C99.
2
3dnl Copyright (C) 2002-2006, 2009-2022 Free Software Foundation, Inc.
4dnl This file is free software; the Free Software Foundation
5dnl gives unlimited permission to copy and/or distribute it,
6dnl with or without modifications, as long as this notice is preserved.
7
8#serial 9
9
10# Prepare for substituting <stdbool.h> if it is not supported.
11
12AC_DEFUN([gl_STDBOOL_H],
13[
14  AC_REQUIRE([AC_CHECK_HEADER_STDBOOL])
15  AC_REQUIRE([AC_CANONICAL_HOST])
16
17  dnl On some platforms, <stdbool.h> does not exist or does not conform to C99.
18  dnl On Solaris 10 with CC=cc CXX=CC, <stdbool.h> exists but is not usable
19  dnl in C++ mode (and no <cstdbool> exists). In this case, we use our
20  dnl replacement, also in C mode (for binary compatibility between C and C++).
21  if test "$ac_cv_header_stdbool_h" = yes; then
22    case "$host_os" in
23      solaris*)
24        if test -z "$GCC"; then
25          GL_GENERATE_STDBOOL_H=true
26        else
27          GL_GENERATE_STDBOOL_H=false
28        fi
29        ;;
30      *)
31        GL_GENERATE_STDBOOL_H=false
32        ;;
33    esac
34  else
35    GL_GENERATE_STDBOOL_H=true
36  fi
37
38  if test "$ac_cv_type__Bool" = yes; then
39    HAVE__BOOL=1
40  else
41    HAVE__BOOL=0
42  fi
43  AC_SUBST([HAVE__BOOL])
44])
45
46# This version of the macro is needed in autoconf <= 2.68.
47
48AC_DEFUN([AC_CHECK_HEADER_STDBOOL],
49  [AC_CACHE_CHECK([for stdbool.h that conforms to C99],
50     [ac_cv_header_stdbool_h],
51     [AC_COMPILE_IFELSE(
52        [AC_LANG_PROGRAM(
53           [[
54             #include <stdbool.h>
55
56             #ifdef __cplusplus
57              typedef bool Bool;
58             #else
59              typedef _Bool Bool;
60              #ifndef bool
61               "error: bool is not defined"
62              #endif
63              #ifndef false
64               "error: false is not defined"
65              #endif
66              #if false
67               "error: false is not 0"
68              #endif
69              #ifndef true
70               "error: true is not defined"
71              #endif
72              #if true != 1
73               "error: true is not 1"
74              #endif
75             #endif
76
77             #ifndef __bool_true_false_are_defined
78              "error: __bool_true_false_are_defined is not defined"
79             #endif
80
81             struct s { Bool s: 1; Bool t; bool u: 1; bool v; } s;
82
83             char a[true == 1 ? 1 : -1];
84             char b[false == 0 ? 1 : -1];
85             char c[__bool_true_false_are_defined == 1 ? 1 : -1];
86             char d[(bool) 0.5 == true ? 1 : -1];
87             /* See body of main program for 'e'.  */
88             char f[(Bool) 0.0 == false ? 1 : -1];
89             char g[true];
90             char h[sizeof (Bool)];
91             char i[sizeof s.t];
92             enum { j = false, k = true, l = false * true, m = true * 256 };
93             /* The following fails for
94                HP aC++/ANSI C B3910B A.05.55 [Dec 04 2003]. */
95             Bool n[m];
96             char o[sizeof n == m * sizeof n[0] ? 1 : -1];
97             char p[-1 - (Bool) 0 < 0 && -1 - (bool) 0 < 0 ? 1 : -1];
98             /* Catch a bug in an HP-UX C compiler.  See
99                https://gcc.gnu.org/ml/gcc-patches/2003-12/msg02303.html
100                https://lists.gnu.org/r/bug-coreutils/2005-11/msg00161.html
101              */
102             Bool q = true;
103             Bool *pq = &q;
104             bool *qq = &q;
105           ]],
106           [[
107             bool e = &s;
108             *pq |= q; *pq |= ! q;
109             *qq |= q; *qq |= ! q;
110             /* Refer to every declared value, to avoid compiler optimizations.  */
111             return (!a + !b + !c + !d + !e + !f + !g + !h + !i + !!j + !k + !!l
112                     + !m + !n + !o + !p + !q + !pq + !qq);
113           ]])],
114        [ac_cv_header_stdbool_h=yes],
115        [ac_cv_header_stdbool_h=no])])
116   AC_CHECK_TYPES([_Bool])
117])
118