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dnl Copyright (C) 2011-2025 Free Software Foundation, Inc. |
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dnl This file is free software; the Free Software Foundation |
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dnl gives unlimited permission to copy and/or distribute it, |
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dnl with or without modifications, as long as this notice is preserved. |
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dnl This file is offered as-is, without any warranty. |
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dnl From Paul Eggert. |
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AC_DEFUN([gl_ASSERT_H], |
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[ |
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AC_CACHE_CHECK([for static_assert], [gl_cv_static_assert], |
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[gl_saved_CFLAGS=$CFLAGS |
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for gl_working in "yes, a keyword" "yes, an <assert.h> macro"; do |
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AS_CASE([$gl_working], |
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[*assert.h*], [CFLAGS="$gl_saved_CFLAGS -DINCLUDE_ASSERT_H"]) |
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AC_COMPILE_IFELSE( |
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[AC_LANG_PROGRAM( |
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[[#if defined __clang__ && __STDC_VERSION__ < 202311 |
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#pragma clang diagnostic error "-Wc2x-extensions" |
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#pragma clang diagnostic error "-Wc++1z-extensions" |
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#endif |
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#ifdef INCLUDE_ASSERT_H |
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#include <assert.h> |
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#endif |
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static_assert (2 + 2 == 4, "arithmetic does not work"); |
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static_assert (2 + 2 == 4); |
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]], |
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[[ |
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static_assert (sizeof (char) == 1, "sizeof does not work"); |
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static_assert (sizeof (char) == 1); |
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]]) |
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], |
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[gl_cv_static_assert=$gl_working], |
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[gl_cv_static_assert=no]) |
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CFLAGS=$gl_saved_CFLAGS |
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test "$gl_cv_static_assert" != no && break |
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done |
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]) |
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GL_GENERATE_ASSERT_H=false |
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AS_CASE([$gl_cv_static_assert], |
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[yes*keyword*], |
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[AC_DEFINE([HAVE_C_STATIC_ASSERT], [1], |
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[Define to 1 if the static_assert keyword works.])], |
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[no], |
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[GL_GENERATE_ASSERT_H=true |
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gl_NEXT_HEADERS([assert.h])]) |
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dnl The "zz" puts this toward config.h's end, to avoid potential |
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dnl collisions with other definitions. |
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dnl Hardcode the known configuration results for GCC and clang, so that |
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dnl a configuration made with the C compiler works also with the C++ compiler |
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dnl and vice versa. |
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dnl The seemingly redundant parentheses are necessary for MSVC 14. |
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dnl #undef assert so that programs are not tempted to use it without |
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dnl specifically including assert.h. |
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dnl Break the #undef_s apart with a comment so that 'configure' does |
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dnl not comment them out. |
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AH_VERBATIM([zzstatic_assert], |
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[#if (!(defined __clang__ \ |
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? (defined __cplusplus \ |
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? __cplusplus >= 201703L \ |
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: __STDC_VERSION__ >= 202000L && __clang_major__ >= 16 \ |
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&& !defined __sun) \ |
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: (defined __GNUC__ \ |
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? (defined __cplusplus \ |
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? __cplusplus >= 201103L && __GNUG__ >= 6 \ |
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: __STDC_VERSION__ >= 202000L && __GNUC__ >= 13 \ |
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&& !defined __sun) \ |
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: defined HAVE_C_STATIC_ASSERT)) \ |
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&& !defined assert \ |
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&& (!defined __cplusplus \ |
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|| (__cpp_static_assert < 201411 \ |
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&& __GNUG__ < 6 && __clang_major__ < 6))) |
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#include <assert.h> |
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#undef/**/assert |
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/* Solaris 11.4 <assert.h> defines static_assert as a macro with 2 arguments. |
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We need it also to be invocable with a single argument. |
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Haiku 2022 <assert.h> does not define static_assert at all. */ |
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#if (__STDC_VERSION__ - 0 >= 201112L) && !defined __cplusplus |
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#undef/**/static_assert |
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#define static_assert _Static_assert |
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#endif |
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#endif]) |
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]) |
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