| # Check for bool that conforms to C2023. | |
| dnl Copyright 2022-2023 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. | |
| AC_DEFUN([gl_C_BOOL], | |
| [ | |
| AC_CACHE_CHECK([for bool, true, false], [gl_cv_c_bool], | |
| [AC_COMPILE_IFELSE( | |
| [AC_LANG_SOURCE([[ | |
| #if true == false | |
| #error "true == false" | |
| #endif | |
| extern bool b; | |
| bool b = true == false;]])], | |
| [gl_cv_c_bool=yes], | |
| [gl_cv_c_bool=no])]) | |
| if test "$gl_cv_c_bool" = yes; then | |
| AC_DEFINE([HAVE_C_BOOL], [1], | |
| [Define to 1 if bool, true and false work as per C2023.]) | |
| fi | |
| AC_CHECK_HEADERS_ONCE([stdbool.h]) | |
| dnl The "zz" puts this toward config.h's end, to avoid potential | |
| dnl collisions with other definitions. | |
| dnl If 'bool', 'true' and 'false' do not work, arrange for them to work. | |
| dnl In C, this means including <stdbool.h> if it is not already included. | |
| dnl However, if the preprocessor mistakenly treats 'true' as 0, | |
| dnl define it to a bool expression equal to 1; this is needed in | |
| dnl Sun C++ 5.11 (Oracle Solaris Studio 12.2, 2010) and older. | |
| AH_VERBATIM([zzbool], | |
| [#ifndef HAVE_C_BOOL | |
| # if !defined __cplusplus && !defined __bool_true_false_are_defined | |
| # if HAVE_STDBOOL_H | |
| # include <stdbool.h> | |
| # else | |
| # if defined __SUNPRO_C | |
| # error "<stdbool.h> is not usable with this configuration. To make it usable, add -D_STDC_C99= to $CC." | |
| # else | |
| # error "<stdbool.h> does not exist on this platform. Use gnulib module 'stdbool-c99' instead of gnulib module 'stdbool'." | |
| # endif | |
| # endif | |
| # endif | |
| # if !true | |
| # define true (!false) | |
| # endif | |
| #endif]) | |
| ]) | |