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# assert-h.m4
dnl Copyright (C) 2011-2022 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.
dnl From Paul Eggert.
AC_DEFUN([gl_ASSERT_H],
[
AC_CACHE_CHECK([for static_assert], [gl_cv_static_assert],
[gl_save_CFLAGS=$CFLAGS
for gl_working in "yes, a keyword" "yes, an <assert.h> macro"; do
AS_CASE([$gl_working],
[*assert.h*], [CFLAGS="$gl_save_CFLAGS -DINCLUDE_ASSERT_H"])
AC_COMPILE_IFELSE(
[AC_LANG_PROGRAM(
[[#if defined __clang__ && __STDC_VERSION__ < 202311
#pragma clang diagnostic error "-Wc2x-extensions"
#pragma clang diagnostic error "-Wc++17-extensions"
#endif
#ifdef INCLUDE_ASSERT_H
#include <assert.h>
#endif
static_assert (2 + 2 == 4, "arithmetic does not work");
static_assert (2 + 2 == 4);
]],
[[
static_assert (sizeof (char) == 1, "sizeof does not work");
static_assert (sizeof (char) == 1);
]])],
[gl_cv_static_assert=$gl_working],
[gl_cv_static_assert=no])
CFLAGS=$gl_save_CFLAGS
test "$gl_cv_static_assert" != no && break
done])
GL_GENERATE_ASSERT_H=false
AS_CASE([$gl_cv_static_assert],
[yes*keyword*],
[AC_DEFINE([HAVE_C_STATIC_ASSERT], [1],
[Define to 1 if the static_assert keyword works.])],
[no],
[GL_GENERATE_ASSERT_H=true
gl_NEXT_HEADERS([assert.h])])
dnl The "zz" puts this toward config.h's end, to avoid potential
dnl collisions with other definitions. #undef assert so that
dnl programs are not tempted to use it without specifically
dnl including assert.h. Break the #undef apart with a comment
dnl so that 'configure' does not comment it out.
AH_VERBATIM([zzstatic_assert],
[#if (!defined HAVE_C_STATIC_ASSERT && !defined assert \
&& (!defined __cplusplus \
|| (__cpp_static_assert < 201411 \
&& __GNUG__ < 6 && __clang_major__ < 6)))
#include <assert.h>
#undef/**/assert
#endif])
])
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