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emacs/m4/stdbool.m4
2011-02-04 21:07:22 -08:00

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# Check for stdbool.h that conforms to C99.
dnl Copyright (C) 2002-2006, 2009-2011 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 4
# Prepare for substituting <stdbool.h> if it is not supported.
AC_DEFUN([AM_STDBOOL_H],
[
AC_REQUIRE([AC_CHECK_HEADER_STDBOOL])
# Define two additional variables used in the Makefile substitution.
if test "$ac_cv_header_stdbool_h" = yes; then
STDBOOL_H=''
else
STDBOOL_H='stdbool.h'
fi
AC_SUBST([STDBOOL_H])
if test "$ac_cv_type__Bool" = yes; then
HAVE__BOOL=1
else
HAVE__BOOL=0
fi
AC_SUBST([HAVE__BOOL])
])
# AM_STDBOOL_H will be renamed to gl_STDBOOL_H in the future.
AC_DEFUN([gl_STDBOOL_H], [AM_STDBOOL_H])
# This version of the macro is needed in autoconf <= 2.68.
AC_DEFUN([AC_CHECK_HEADER_STDBOOL],
[AC_CACHE_CHECK([for stdbool.h that conforms to C99],
[ac_cv_header_stdbool_h],
[AC_COMPILE_IFELSE(
[AC_LANG_PROGRAM(
[[
#include <stdbool.h>
#ifndef bool
"error: bool is not defined"
#endif
#ifndef false
"error: false is not defined"
#endif
#if false
"error: false is not 0"
#endif
#ifndef true
"error: true is not defined"
#endif
#if true != 1
"error: true is not 1"
#endif
#ifndef __bool_true_false_are_defined
"error: __bool_true_false_are_defined is not defined"
#endif
struct s { _Bool s: 1; _Bool t; } s;
char a[true == 1 ? 1 : -1];
char b[false == 0 ? 1 : -1];
char c[__bool_true_false_are_defined == 1 ? 1 : -1];
char d[(bool) 0.5 == true ? 1 : -1];
/* See body of main program for 'e'. */
char f[(_Bool) 0.0 == false ? 1 : -1];
char g[true];
char h[sizeof (_Bool)];
char i[sizeof s.t];
enum { j = false, k = true, l = false * true, m = true * 256 };
/* The following fails for
HP aC++/ANSI C B3910B A.05.55 [Dec 04 2003]. */
_Bool n[m];
char o[sizeof n == m * sizeof n[0] ? 1 : -1];
char p[-1 - (_Bool) 0 < 0 && -1 - (bool) 0 < 0 ? 1 : -1];
/* Catch a bug in an HP-UX C compiler. See
http://gcc.gnu.org/ml/gcc-patches/2003-12/msg02303.html
http://lists.gnu.org/archive/html/bug-coreutils/2005-11/msg00161.html
*/
_Bool q = true;
_Bool *pq = &q;
]],
[[
bool e = &s;
*pq |= q;
*pq |= ! q;
/* Refer to every declared value, to avoid compiler optimizations. */
return (!a + !b + !c + !d + !e + !f + !g + !h + !i + !!j + !k + !!l
+ !m + !n + !o + !p + !q + !pq);
]])],
[ac_cv_header_stdbool_h=yes],
[ac_cv_header_stdbool_h=no])])
AC_CHECK_TYPES([_Bool])
])