stdbool.m4

一个C语言写的快速贝叶斯垃圾邮件过滤工具

dnl -*- Autoconf -*-
dnl The AC_HEADER_STDBOOL code was taken from autoconf 2.57.
dnl
dnl It was modified to only define the AC_HEADER_STDBOOL test,
dnl which is not present in autoconf 2.54 and older, because
dnl many distributions (Red Hat Linux 8.0, SuSE Linux 8.1) still ship
dnl autoconf 2.53.
dnl -- Matthias Andree

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# Written by David MacKenzie, with help from
# Fran鏾is Pinard, Karl Berry, Richard Pixley, Ian Lance Taylor,
# Roland McGrath, Noah Friedman, david d zuhn, and many others.

AC_DEFUN([AC_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];
        bool e = &s;
        char f[(_Bool) -0.0 == false ? 1 : -1];
        char g[true];
        char h[sizeof (_Bool)];
        char i[sizeof s.t];
      ]],
      [[ return !a + !b + !c + !d + !e + !f + !g + !h + !i; ]])],
      [ac_cv_header_stdbool_h=yes],
      [ac_cv_header_stdbool_h=no])])
AC_CHECK_TYPES([_Bool])
if test $ac_cv_header_stdbool_h = yes; then
  AC_DEFINE(HAVE_STDBOOL_H, 1, [Define to 1 if stdbool.h conforms to C99.])
fi
])# AC_HEADER_STDBOOL