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Diffstat (limited to 'm4/mode_t.m4')
| -rw-r--r-- | m4/mode_t.m4 | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/m4/mode_t.m4 b/m4/mode_t.m4 new file mode 100644 index 00000000000..75d372a4a8a --- /dev/null +++ b/m4/mode_t.m4 @@ -0,0 +1,26 @@ +# mode_t.m4 serial 2 +dnl Copyright (C) 2009-2017 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 6.5.2.2.(6)) of the type mode_t. +AC_DEFUN([gl_PROMOTED_TYPE_MODE_T], +[ + AC_REQUIRE([AC_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];]])], + [gl_cv_promoted_mode_t='int'], + [gl_cv_promoted_mode_t='mode_t']) + ]) + 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.]) +]) |