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author | Paul Eggert <eggert@cs.ucla.edu> | 2010-05-05 13:57:26 -0700 |
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committer | Paul Eggert <eggert@cs.ucla.edu> | 2010-05-05 13:57:26 -0700 |
commit | 8a11db185bb84ee7d2be080ffc71214e14824767 (patch) | |
tree | 5e66987780188c51b2081802a34bd3a146dcba9b /lib/verify.h | |
parent | 8465329af7e7da7e9e8c61a3c0f71d4cee89ccd5 (diff) | |
download | gnulib-8a11db185bb84ee7d2be080ffc71214e14824767.tar.gz |
Further improvements to verify.h, suggested by Eric Blake.
* lib/verify.h (_GL_CONCAT, _GL_CONCAT0, _GL_GENSYM): Renamed from
the GL_* versions, to avoid collision with OpenGL.
(_GL_COUNTER): New macro, so that we can fall back on __LINE__ if
__COUNTER__ doesn't work. Test that __COUNTER__ increments rather
than testing merely whether it's defined.
Diffstat (limited to 'lib/verify.h')
-rw-r--r-- | lib/verify.h | 29 |
1 files changed, 16 insertions, 13 deletions
diff --git a/lib/verify.h b/lib/verify.h index dbca35c817..a0849a8c4b 100644 --- a/lib/verify.h +++ b/lib/verify.h @@ -69,9 +69,9 @@ if the entity names are not disambiguated. A workaround is to attach the current line number to the entity name: - #define GL_CONCAT0(x, y) x##y - #define GL_CONCAT(x, y) GL_CONCAT0 (x, y) - extern struct {...} * GL_CONCAT(dummy,__LINE__); + #define _GL_CONCAT0(x, y) x##y + #define _GL_CONCAT(x, y) _GL_CONCAT0 (x, y) + extern struct {...} * _GL_CONCAT(dummy,__LINE__); But this has the problem that two invocations of verify from within the same macro would collide, since the __LINE__ value @@ -123,19 +123,22 @@ Use a template type to work around the problem. */ /* Concatenate two preprocessor tokens. */ -# define GL_CONCAT(x, y) GL_CONCAT0 (x, y) -# define GL_CONCAT0(x, y) x##y - -/* __COUNTER__ evaluates to 0, 1, 2,..., adding one one each time the - preprocessor uses it. If the preprocessor doesn't support this - builtin macro, define it to 0. */ -# ifndef __COUNTER__ -# define __COUNTER__ 0 +# define _GL_CONCAT(x, y) _GL_CONCAT0 (x, y) +# define _GL_CONCAT0(x, y) x##y + +/* _GL_COUNTER is an integer, preferably one that changes each time we + use it. Use __COUNTER__ if it works, falling back on __LINE__ + otherwise. __LINE__ isn't perfect, but it's better than a + constant. */ +# if defined __COUNTER__ && __COUNTER__ != __COUNTER__ +# define _GL_COUNTER __COUNTER__ +# else +# define _GL_COUNTER __LINE__ # endif /* Generate a symbol with the given prefix, making it unique if possible. */ -# define GL_GENSYM(prefix) GL_CONCAT(prefix, __COUNTER__) +# define _GL_GENSYM(prefix) _GL_CONCAT(prefix, _GL_COUNTER) /* Verify requirement R at compile-time, as an integer constant expression. Return 1. */ @@ -155,6 +158,6 @@ template <int w> trailing ';'. */ # define verify(R) \ - extern int (* GL_GENSYM(verify_function) (void)) [verify_true (R)] + extern int (* _GL_GENSYM(verify_function) (void)) [verify_true (R)] #endif |