1# Check for stdbool.h that conforms to C99.
2
3dnl Copyright (C) 2002-2006, 2009-2021 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 8
9
10# Prepare for substituting <stdbool.h> if it is not supported.
11
12AC_DEFUN([AM_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 "$GCC"; then
25          STDBOOL_H='stdbool.h'
26        else
27          STDBOOL_H=''
28        fi
29        ;;
30      *)
31        STDBOOL_H=''
32        ;;
33    esac
34  else
35    STDBOOL_H='stdbool.h'
36  fi
37  AC_SUBST([STDBOOL_H])
38  AM_CONDITIONAL([GL_GENERATE_STDBOOL_H], [test -n "$STDBOOL_H"])
39
40  if test "$ac_cv_type__Bool" = yes; then
41    HAVE__BOOL=1
42  else
43    HAVE__BOOL=0
44  fi
45  AC_SUBST([HAVE__BOOL])
46])
47
48# AM_STDBOOL_H will be renamed to gl_STDBOOL_H in the future.
49AC_DEFUN([gl_STDBOOL_H], [AM_STDBOOL_H])
50
51# This version of the macro is needed in autoconf <= 2.68.
52
53AC_DEFUN([AC_CHECK_HEADER_STDBOOL],
54  [AC_CACHE_CHECK([for stdbool.h that conforms to C99],
55     [ac_cv_header_stdbool_h],
56     [AC_COMPILE_IFELSE(
57        [AC_LANG_PROGRAM(
58           [[
59             #include <stdbool.h>
60
61             #ifdef __cplusplus
62              typedef bool Bool;
63             #else
64              typedef _Bool Bool;
65              #ifndef bool
66               "error: bool is not defined"
67              #endif
68              #ifndef false
69               "error: false is not defined"
70              #endif
71              #if false
72               "error: false is not 0"
73              #endif
74              #ifndef true
75               "error: true is not defined"
76              #endif
77              #if true != 1
78               "error: true is not 1"
79              #endif
80             #endif
81
82             #ifndef __bool_true_false_are_defined
83              "error: __bool_true_false_are_defined is not defined"
84             #endif
85
86             struct s { Bool s: 1; Bool t; bool u: 1; bool v; } s;
87
88             char a[true == 1 ? 1 : -1];
89             char b[false == 0 ? 1 : -1];
90             char c[__bool_true_false_are_defined == 1 ? 1 : -1];
91             char d[(bool) 0.5 == true ? 1 : -1];
92             /* See body of main program for 'e'.  */
93             char f[(Bool) 0.0 == false ? 1 : -1];
94             char g[true];
95             char h[sizeof (Bool)];
96             char i[sizeof s.t];
97             enum { j = false, k = true, l = false * true, m = true * 256 };
98             /* The following fails for
99                HP aC++/ANSI C B3910B A.05.55 [Dec 04 2003]. */
100             Bool n[m];
101             char o[sizeof n == m * sizeof n[0] ? 1 : -1];
102             char p[-1 - (Bool) 0 < 0 && -1 - (bool) 0 < 0 ? 1 : -1];
103             /* Catch a bug in an HP-UX C compiler.  See
104                https://gcc.gnu.org/ml/gcc-patches/2003-12/msg02303.html
105                https://lists.gnu.org/r/bug-coreutils/2005-11/msg00161.html
106              */
107             Bool q = true;
108             Bool *pq = &q;
109             bool *qq = &q;
110           ]],
111           [[
112             bool e = &s;
113             *pq |= q; *pq |= ! q;
114             *qq |= q; *qq |= ! q;
115             /* Refer to every declared value, to avoid compiler optimizations.  */
116             return (!a + !b + !c + !d + !e + !f + !g + !h + !i + !!j + !k + !!l
117                     + !m + !n + !o + !p + !q + !pq + !qq);
118           ]])],
119        [ac_cv_header_stdbool_h=yes],
120        [ac_cv_header_stdbool_h=no])])
121   AC_CHECK_TYPES([_Bool])
122])
123