m4/stdbool.m4

   1 # Check for stdbool.h that conforms to C99.
   2
   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.
   7
   8 #serial 3
   9
  10 # Prepare for substituting <stdbool.h> if it is not supported.
  11
  12 AC_DEFUN([AM_STDBOOL_H],
  13 [
  14   AC_REQUIRE([AC_HEADER_STDBOOL])
  15
  16   # Define two additional variables used in the Makefile substitution.
  17
  18   if test "$ac_cv_header_stdbool_h" = yes; then
  19     STDBOOL_H=''
  20   else
  21     STDBOOL_H='stdbool.h'
  22   fi
  23   AC_SUBST([STDBOOL_H])
  24
  25   if test "$ac_cv_type__Bool" = yes; then
  26     HAVE__BOOL=1
  27   else
  28     HAVE__BOOL=0
  29   fi
  30   AC_SUBST([HAVE__BOOL])
  31 ])
  32
  33 # AM_STDBOOL_H will be renamed to gl_STDBOOL_H in the future.
  34 AC_DEFUN([gl_STDBOOL_H], [AM_STDBOOL_H])
  35
  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 xlc and clang due to relying on extensions.
  39
  40 AC_DEFUN([AC_HEADER_STDBOOL],
  41   [AC_CACHE_CHECK([for stdbool.h that conforms to C99],
  42      [ac_cv_header_stdbool_h],
  43      [AC_COMPILE_IFELSE(
  44         [AC_LANG_PROGRAM(
  45            [[
  46              #include <stdbool.h>
  47              #ifndef bool
  48               "error: bool is not defined"
  49              #endif
  50              #ifndef false
  51               "error: false is not defined"
  52              #endif
  53              #if false
  54               "error: false is not 0"
  55              #endif
  56              #ifndef true
  57               "error: true is not defined"
  58              #endif
  59              #if true != 1
  60               "error: true is not 1"
  61              #endif
  62              #ifndef __bool_true_false_are_defined
  63               "error: __bool_true_false_are_defined is not defined"
  64              #endif
  65
  66              struct s { _Bool s: 1; _Bool t; } s;
  67
  68              char a[true == 1 ? 1 : -1];
  69              char b[false == 0 ? 1 : -1];
  70              char c[__bool_true_false_are_defined == 1 ? 1 : -1];
  71              char d[(bool) 0.5 == true ? 1 : -1];
  72              /* See body of main program for 'e'.  */
  73              char f[(_Bool) 0.0 == false ? 1 : -1];
  74              char g[true];
  75              char h[sizeof (_Bool)];
  76              char i[sizeof s.t];
  77              enum { j = false, k = true, l = false * true, m = true * 256 };
  78              /* The following fails for
  79                 HP aC++/ANSI C B3910B A.05.55 [Dec 04 2003]. */
  80              _Bool n[m];
  81              char o[sizeof n == m * sizeof n[0] ? 1 : -1];
  82              char p[-1 - (_Bool) 0 < 0 && -1 - (bool) 0 < 0 ? 1 : -1];
  83              /* Catch a bug in an HP-UX C compiler.  See
  84                 http://gcc.gnu.org/ml/gcc-patches/2003-12/msg02303.html
  85                 http://lists.gnu.org/archive/html/bug-coreutils/2005-11/msg00161.html
  86               */
  87              _Bool q = true;
  88              _Bool *pq = &q;
  89            ]],
  90            [[
  91              bool e = &s;
  92              *pq |= q;
  93              *pq |= ! q;
  94              /* Refer to every declared value, to avoid compiler optimizations.  */
  95              return (!a + !b + !c + !d + !e + !f + !g + !h + !i + !!j + !k + !!l
  96                      + !m + !n + !o + !p + !q + !pq);
  97            ]])],
  98         [ac_cv_header_stdbool_h=yes],
  99         [ac_cv_header_stdbool_h=no])])
 100    AC_CHECK_TYPES([_Bool])
 101    if test $ac_cv_header_stdbool_h = yes; then
 102      AC_DEFINE([HAVE_STDBOOL_H], [1], [Define to 1 if stdbool.h conforms to C99.])
 103    fi])