Diffstat (limited to 'm4')
1 files changed, 26 insertions, 0 deletions
diff --git a/m4/mode_t.m4 b/m4/mode_t.m4
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+# mode_t.m4 serial 2
+dnl Copyright (C) 2009-2012 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.
+# For using mode_t, it's sufficient to use AC_TYPE_MODE_T and
+# include <sys/types.h>.
+# Define PROMOTED_MODE_T to the type that is the result of "default argument
+# promotion" (ISO C 18.104.22.168.(6)) of the type mode_t.
+ AC_CACHE_CHECK([for promoted mode_t type], [gl_cv_promoted_mode_t], [
+ dnl Assume mode_t promotes to 'int' if and only if it is smaller than 'int',
+ dnl and to itself otherwise. This assumption is not guaranteed by the ISO C
+ dnl standard, but we don't know of any real-world counterexamples.
+ AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <sys/types.h>]],
+ [[typedef int array[2 * (sizeof (mode_t) < sizeof (int)) - 1];]])],
+ AC_DEFINE_UNQUOTED([PROMOTED_MODE_T], [$gl_cv_promoted_mode_t],
+ [Define to the type that is the result of default argument promotions of type mode_t.])