m4/stdbool.m4

   1 # Check for stdbool.h that conforms to C99.
   2
   3 dnl Copyright (C) 2002-2006, 2009-2014 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 5
   9
  10 # Prepare for substituting <stdbool.h> if it is not supported.
  11
  12 AC_DEFUN([AM_STDBOOL_H],
  13 [
  14   AC_REQUIRE([AC_CHECK_HEADER_STDBOOL])
  15
  16   # Define two additional variables used in the Makefile substitution.
  17
  18   if test "$ac_cv_header_stdbool_h" = yes; then
  19     STDBOOL_H=''
  20   else
  21     STDBOOL_H='stdbool.h'
  22   fi
  23   AC_SUBST([STDBOOL_H])
  24   AM_CONDITIONAL([GL_GENERATE_STDBOOL_H], [test -n "$STDBOOL_H"])
  25
  26   if test "$ac_cv_type__Bool" = yes; then
  27     HAVE__BOOL=1
  28   else
  29     HAVE__BOOL=0
  30   fi
  31   AC_SUBST([HAVE__BOOL])
  32 ])
  33
  34 # AM_STDBOOL_H will be renamed to gl_STDBOOL_H in the future.
  35 AC_DEFUN([gl_STDBOOL_H], [AM_STDBOOL_H])
  36
  37 # This version of the macro is needed in autoconf <= 2.68.
  38
  39 AC_DEFUN([AC_CHECK_HEADER_STDBOOL],
  40   [AC_CACHE_CHECK([for stdbool.h that conforms to C99],
  41      [ac_cv_header_stdbool_h],
  42      [AC_COMPILE_IFELSE(
  43         [AC_LANG_PROGRAM(
  44            [[
  45              #include <stdbool.h>
  46              #ifndef bool
  47               "error: bool is not defined"
  48              #endif
  49              #ifndef false
  50               "error: false is not defined"
  51              #endif
  52              #if false
  53               "error: false is not 0"
  54              #endif
  55              #ifndef true
  56               "error: true is not defined"
  57              #endif
  58              #if true != 1
  59               "error: true is not 1"
  60              #endif
  61              #ifndef __bool_true_false_are_defined
  62               "error: __bool_true_false_are_defined is not defined"
  63              #endif
  64
  65              struct s { _Bool s: 1; _Bool t; } s;
  66
  67              char a[true == 1 ? 1 : -1];
  68              char b[false == 0 ? 1 : -1];
  69              char c[__bool_true_false_are_defined == 1 ? 1 : -1];
  70              char d[(bool) 0.5 == true ? 1 : -1];
  71              /* See body of main program for 'e'.  */
  72              char f[(_Bool) 0.0 == false ? 1 : -1];
  73              char g[true];
  74              char h[sizeof (_Bool)];
  75              char i[sizeof s.t];
  76              enum { j = false, k = true, l = false * true, m = true * 256 };
  77              /* The following fails for
  78                 HP aC++/ANSI C B3910B A.05.55 [Dec 04 2003]. */
  79              _Bool n[m];
  80              char o[sizeof n == m * sizeof n[0] ? 1 : -1];
  81              char p[-1 - (_Bool) 0 < 0 && -1 - (bool) 0 < 0 ? 1 : -1];
  82              /* Catch a bug in an HP-UX C compiler.  See
  83                 http://gcc.gnu.org/ml/gcc-patches/2003-12/msg02303.html
  84                 http://lists.gnu.org/archive/html/bug-coreutils/2005-11/msg00161.html
  85               */
  86              _Bool q = true;
  87              _Bool *pq = &q;
  88            ]],
  89            [[
  90              bool e = &s;
  91              *pq |= q;
  92              *pq |= ! q;
  93              /* Refer to every declared value, to avoid compiler optimizations.  */
  94              return (!a + !b + !c + !d + !e + !f + !g + !h + !i + !!j + !k + !!l
  95                      + !m + !n + !o + !p + !q + !pq);
  96            ]])],
  97         [ac_cv_header_stdbool_h=yes],
  98         [ac_cv_header_stdbool_h=no])])
  99    AC_CHECK_TYPES([_Bool])
 100 ])