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guile/m4/stdbool.m4
Josselin Poiret edfca3b7e5 Update gnulib to 0.1.5414-8204d and add posix_spawn, posix_spawnp.
Signed-off-by: Ludovic Courtès <ludo@gnu.org>
2023-01-12 16:41:29 +01:00

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# Check for stdbool.h that conforms to C99.
dnl Copyright (C) 2002-2006, 2009-2022 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
dnl with or without modifications, as long as this notice is preserved.
#serial 9
# Prepare for substituting <stdbool.h> if it is not supported.
AC_DEFUN([gl_STDBOOL_H],
[
AC_REQUIRE([AC_CHECK_HEADER_STDBOOL])
AC_REQUIRE([AC_CANONICAL_HOST])
dnl On some platforms, <stdbool.h> does not exist or does not conform to C99.
dnl On Solaris 10 with CC=cc CXX=CC, <stdbool.h> exists but is not usable
dnl in C++ mode (and no <cstdbool> exists). In this case, we use our
dnl replacement, also in C mode (for binary compatibility between C and C++).
if test "$ac_cv_header_stdbool_h" = yes; then
case "$host_os" in
solaris*)
if test -z "$GCC"; then
GL_GENERATE_STDBOOL_H=true
else
GL_GENERATE_STDBOOL_H=false
fi
;;
*)
GL_GENERATE_STDBOOL_H=false
;;
esac
else
GL_GENERATE_STDBOOL_H=true
fi
if test "$ac_cv_type__Bool" = yes; then
HAVE__BOOL=1
else
HAVE__BOOL=0
fi
AC_SUBST([HAVE__BOOL])
])
m4_version_prereq([2.72], [], [
AC_DEFUN([AC_CHECK_HEADER_STDBOOL],
[AC_CHECK_TYPES([_Bool])
AC_CACHE_CHECK([for stdbool.h that conforms to C99 or later],
[ac_cv_header_stdbool_h],
[AC_COMPILE_IFELSE(
[AC_LANG_PROGRAM(
[[#include <stdbool.h>
/* "true" and "false" should be usable in #if expressions and
integer constant expressions, and "bool" should be a valid
type name.
Although C 1999 requires bool, true, and false to be macros,
C 2023 and C++ 2011 overrule that, so do not test for that.
Although C 1999 requires __bool_true_false_are_defined and
_Bool, C 2023 says they are obsolescent, so do not require
them. */
#if !true
#error "'true' is not true"
#endif
#if true != 1
#error "'true' is not equal to 1"
#endif
char b[true == 1 ? 1 : -1];
char c[true];
#if false
#error "'false' is not false"
#endif
#if false != 0
#error "'false' is not equal to 0"
#endif
char d[false == 0 ? 1 : -1];
enum { e = false, f = true, g = false * true, h = true * 256 };
char i[(bool) 0.5 == true ? 1 : -1];
char j[(bool) 0.0 == false ? 1 : -1];
char k[sizeof (bool) > 0 ? 1 : -1];
struct sb { bool s: 1; bool t; } s;
char l[sizeof s.t > 0 ? 1 : -1];
/* The following fails for
HP aC++/ANSI C B3910B A.05.55 [Dec 04 2003]. */
bool m[h];
char n[sizeof m == h * sizeof m[0] ? 1 : -1];
char o[-1 - (bool) 0 < 0 ? 1 : -1];
/* Catch a bug in an HP-UX C compiler. See
https://gcc.gnu.org/ml/gcc-patches/2003-12/msg02303.html
https://lists.gnu.org/r/bug-coreutils/2005-11/msg00161.html
*/
bool p = true;
bool *pp = &p;
]],
[[
bool ps = &s;
*pp |= p;
*pp |= ! p;
/* Refer to every declared value, so they cannot be
discarded as unused. */
return (!a + !b + !c + !d + !e + !f + !g + !h + !i + !j + !k
+ !l + !m + !n + !o + !p + !pp + !ps);
]])],
[ac_cv_header_stdbool_h=yes],
[ac_cv_header_stdbool_h=no])])
])# AC_CHECK_HEADER_STDBOOL
]) # m4_version_prereq 2.72