diff --git a/acinclude.m4 b/acinclude.m4 index f228cd71fd..861ca2261a 100644 --- a/acinclude.m4 +++ b/acinclude.m4 @@ -3,6 +3,7 @@ m4_include([m4.include/ax_path_lib_pcre.m4]) m4_include([m4.include/dx_doxygen.m4]) m4_include([m4.include/mc-cflags.m4]) m4_include([m4.include/mc-check-search-type.m4]) +m4_include([m4.include/mode_t.m4]) m4_include([m4.include/ls-mntd-fs.m4]) m4_include([m4.include/fstypename.m4]) m4_include([m4.include/fsusage.m4]) diff --git a/configure.ac b/configure.ac index 4962f03ae1..d0d8358cc5 100644 --- a/configure.ac +++ b/configure.ac @@ -177,6 +177,7 @@ AC_CHECK_SIZEOF(uintmax_t) AC_TYPE_OFF_T AC_CHECK_SIZEOF(off_t) AC_TYPE_MODE_T +gl_PROMOTED_TYPE_MODE_T AC_TYPE_PID_T AC_TYPE_UID_T diff --git a/lib/vfs/interface.c b/lib/vfs/interface.c index 64acb96283..53934c0352 100644 --- a/lib/vfs/interface.c +++ b/lib/vfs/interface.c @@ -200,7 +200,10 @@ mc_open (const vfs_path_t * vpath, int flags, ...) { va_list ap; va_start (ap, flags); - mode = va_arg (ap, mode_t); + /* We have to use PROMOTED_MODE_T instead of mode_t. Doing 'va_arg (ap, mode_t)' + * fails on systems where 'mode_t' is smaller than 'int' because of C's "default + * argument promotions". */ + mode = va_arg (ap, PROMOTED_MODE_T); va_end (ap); } diff --git a/m4.include/mode_t.m4 b/m4.include/mode_t.m4 new file mode 100644 index 0000000000..0cd40dba49 --- /dev/null +++ b/m4.include/mode_t.m4 @@ -0,0 +1,26 @@ +# mode_t.m4 serial 2 +dnl Copyright (C) 2009-2016 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 . + +# 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 ]], + [[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.]) +])