1# mode_t.m4 serial 2
2dnl Copyright (C) 2009-2020 Free Software Foundation, Inc.
3dnl This file is free software; the Free Software Foundation
4dnl gives unlimited permission to copy and/or distribute it,
5dnl with or without modifications, as long as this notice is preserved.
6
7# For using mode_t, it's sufficient to use AC_TYPE_MODE_T and
8# include <sys/types.h>.
9
10# Define PROMOTED_MODE_T to the type that is the result of "default argument
11# promotion" (ISO C 6.5.2.2.(6)) of the type mode_t.
12AC_DEFUN([gl_PROMOTED_TYPE_MODE_T],
13[
14  AC_REQUIRE([AC_TYPE_MODE_T])
15  AC_CACHE_CHECK([for promoted mode_t type], [gl_cv_promoted_mode_t], [
16    dnl Assume mode_t promotes to 'int' if and only if it is smaller than 'int',
17    dnl and to itself otherwise. This assumption is not guaranteed by the ISO C
18    dnl standard, but we don't know of any real-world counterexamples.
19    AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <sys/types.h>]],
20      [[typedef int array[2 * (sizeof (mode_t) < sizeof (int)) - 1];]])],
21      [gl_cv_promoted_mode_t='int'],
22      [gl_cv_promoted_mode_t='mode_t'])
23  ])
24  AC_DEFINE_UNQUOTED([PROMOTED_MODE_T], [$gl_cv_promoted_mode_t],
25    [Define to the type that is the result of default argument promotions of type mode_t.])
26])
27