/* ignore a function return without a compiler warning
- Copyright (C) 2008-2010 Free Software Foundation, Inc.
+ Copyright (C) 2008-2012 Free Software Foundation, Inc.
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
-/* Written by Jim Meyering. */
+/* Written by Jim Meyering, Eric Blake and Pádraig Brady. */
-/* Use these functions to avoid a warning when using a function declared with
+/* Use "ignore_value" to avoid a warning when using a function declared with
gcc's warn_unused_result attribute, but for which you really do want to
ignore the result. Traditionally, people have used a "(void)" cast to
indicate that a function's return value is deliberately unused. However,
"copy.c:233: warning: ignoring return value of 'fchown',
declared with attribute warn_unused_result". */
-static inline void ignore_value (int i) { (void) i; }
-static inline void ignore_ptr (void* p) { (void) p; }
-/* FIXME: what about aggregate types? */
+#ifndef _GL_IGNORE_VALUE_H
+# define _GL_IGNORE_VALUE_H
+
+/* The __attribute__((__warn_unused_result__)) feature
+ is available in gcc versions 3.4 and newer,
+ while the typeof feature has been available since 2.7 at least. */
+# if __GNUC__ < 3 || (__GNUC__ == 3 && __GNUC_MINOR__ < 4)
+# define ignore_value(x) ((void) (x))
+# else
+# define ignore_value(x) (({ __typeof__ (x) __x = (x); (void) __x; }))
+# endif
+
+#endif