| # Check for stdnoreturn.h that conforms to C11. |
| |
| dnl Copyright 2012-2020 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. |
| |
| # Prepare for substituting <stdnoreturn.h> if it is not supported. |
| |
| AC_DEFUN([gl_STDNORETURN_H], |
| [ |
| AC_REQUIRE([AC_CANONICAL_HOST]) |
| case "$host_os" in |
| cygwin*) |
| dnl Regardless whether a working <stdnoreturn.h> exists or not, |
| dnl we need our own <stdnoreturn.h>, because of the definition |
| dnl of _Noreturn done by gnulib-common.m4. |
| STDNORETURN_H='stdnoreturn.h' |
| ;; |
| *) |
| AC_CACHE_CHECK([for working stdnoreturn.h], |
| [gl_cv_header_working_stdnoreturn_h], |
| [AC_COMPILE_IFELSE( |
| [AC_LANG_PROGRAM( |
| [[#include <stdlib.h> |
| #include <stdnoreturn.h> |
| /* Do not check for 'noreturn' after the return type. |
| C11 allows it, but it's rarely done that way |
| and circa-2012 bleeding-edge GCC rejects it when given |
| -Werror=old-style-declaration. */ |
| noreturn void foo1 (void) { exit (0); } |
| _Noreturn void foo2 (void) { exit (0); } |
| int testit (int argc, char **argv) |
| { |
| if (argc & 1) |
| return 0; |
| (argv[0][0] ? foo1 : foo2) (); |
| } |
| ]])], |
| [gl_cv_header_working_stdnoreturn_h=yes], |
| [gl_cv_header_working_stdnoreturn_h=no])]) |
| if test $gl_cv_header_working_stdnoreturn_h = yes; then |
| STDNORETURN_H='' |
| else |
| STDNORETURN_H='stdnoreturn.h' |
| fi |
| ;; |
| esac |
| AC_SUBST([STDNORETURN_H]) |
| AM_CONDITIONAL([GL_GENERATE_STDNORETURN_H], [test -n "$STDNORETURN_H"]) |
| ]) |
