3 dnl Copyright (C) 2009-2024 Free Software Foundation, Inc.
4 dnl This file is free software; the Free Software Foundation
5 dnl gives unlimited permission to copy and/or distribute it,
6 dnl with or without modifications, as long as this notice is preserved.
8 # For using mode_t, it's sufficient to use AC_TYPE_MODE_T and
9 # include <sys/types.h>.
11 # Define PROMOTED_MODE_T to the type that is the result of "default argument
12 # promotion" (ISO C 6.5.2.2.(6)) of the type mode_t.
13 AC_DEFUN([gl_PROMOTED_TYPE_MODE_T],
15 AC_REQUIRE([AC_TYPE_MODE_T])
16 AC_CACHE_CHECK([for promoted mode_t type], [gl_cv_promoted_mode_t], [
17 dnl Assume mode_t promotes to 'int' if and only if it is smaller than 'int',
18 dnl and to itself otherwise. This assumption is not guaranteed by the ISO C
19 dnl standard, but we don't know of any real-world counterexamples.
20 AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <sys/types.h>]],
21 [[typedef int array[2 * (sizeof (mode_t) < sizeof (int)) - 1];]])],
22 [gl_cv_promoted_mode_t='int'],
23 [gl_cv_promoted_mode_t='mode_t'])
25 AC_DEFINE_UNQUOTED([PROMOTED_MODE_T], [$gl_cv_promoted_mode_t],
26 [Define to the type that is the result of default argument promotions of type mode_t.])