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
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. */
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