ignore-value: revert previous code change

[gnulib.git] / lib / ignore-value.h

diff --git a/lib/ignore-value.h b/lib/ignore-value.h
index 52804dc..633c44a 100644 (file)
--- a/lib/ignore-value.h
+++ b/lib/ignore-value.h
@@ -1,6 +1,6 @@
 /* ignore a function return without a compiler warning
 
-   Copyright (C) 2008-2011 Free Software Foundation, Inc.
+   Copyright (C) 2008-2013 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
@@ -15,7 +15,7 @@
    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 and Pádraig Brady.  */
+/* Written by Jim Meyering, Eric Blake and Pádraig Brady.  */
 
 /* 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
@@ -33,28 +33,18 @@
    declared with attribute warn_unused_result".  */
 
 #ifndef _GL_IGNORE_VALUE_H
-# define _GL_IGNORE_VALUE_H
-
-# include <stdint.h>
-
-# ifndef ATTRIBUTE_DEPRECATED
-/* The __attribute__((__deprecated__)) feature
-   is available in gcc versions 3.1 and newer.  */
-#  if __GNUC__ < 3 || (__GNUC__ == 3 && __GNUC_MINOR__ < 1)
-#   define ATTRIBUTE_DEPRECATED /* empty */
-#  else
-#   define ATTRIBUTE_DEPRECATED __attribute__ ((__deprecated__))
-#  endif
-# endif
-
-# if __GNUC__ < 3 || (__GNUC__ == 3 && __GNUC_MINOR__ < 1)
-#  define ignore_value(x) ((void) (x))
-# else
-#  define ignore_value(x) (({ __typeof__ (x) __x = (x); (void) __x; }))
-# endif
-
-/* ignore_value works for both scalars and pointers; deprecate ignore_ptr.  */
-static inline void ATTRIBUTE_DEPRECATED
-ignore_ptr (void *p) { (void) p; } /* deprecated: use ignore_value */
+#define _GL_IGNORE_VALUE_H
+
+/* Normally casting an expression to void discards its value, but GCC
+   versions 3.4 and newer have __attribute__ ((__warn_unused_result__))
+   which may cause unwanted diagnostics in that case.  Use __typeof__
+   and __extension__ to work around the problem, if the workaround is
+   known to be needed.  */
+#if 3 < __GNUC__ + (4 <= __GNUC_MINOR__)
+# define ignore_value(x) \
+    (__extension__ ({ __typeof__ (x) __x = (x); (void) __x; }))
+#else
+# define ignore_value(x) ((void) (x))
+#endif
 
 #endif