diff options
Diffstat (limited to 'lib/ignore-value.h')
| -rw-r--r-- | lib/ignore-value.h | 25 |
1 files changed, 14 insertions, 11 deletions
diff --git a/lib/ignore-value.h b/lib/ignore-value.h index 63ecde85..4dd0946d 100644 --- a/lib/ignore-value.h +++ b/lib/ignore-value.h @@ -1,6 +1,6 @@ /* ignore a function return without a compiler warning - Copyright (C) 2008-2013 Free Software Foundation, Inc. + Copyright (C) 2008-2014 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 @@ -33,15 +33,18 @@ declared with attribute warn_unused_result". */ #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 +#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 |