diff options
| -rw-r--r-- | lib/verify.h | 28 |
1 files changed, 9 insertions, 19 deletions
diff --git a/lib/verify.h b/lib/verify.h index c755762aa..828a42577 100644 --- a/lib/verify.h +++ b/lib/verify.h @@ -21,34 +21,24 @@ #ifndef VERIFY_H # define VERIFY_H 1 -# define GL_CONCAT0(x, y) x##y -# define GL_CONCAT(x, y) GL_CONCAT0 (x, y) +/* Each of these macros macros verifies that its argument R is a + nonzero constant expression. To be portable, R's type must be + integer (or boolean). Unlike assert, there is no run-time + overhead. */ -/* A type that is valid if and only if R is nonzero. - R should be an integer constant expression. - verify_type__ and verify_error_if_negative_size__ are symbols that - are private to this header file. */ +/* A type that is valid if and only if R is a nonzero constant expression. + The symbols verify_type__ and verify_error_if_negative_size__ are + private to this header file. */ # define verify_type__(R) \ struct { int verify_error_if_negative_size__ : (R) ? 1 : -1; } -/* Verify requirement R at compile-time, as a declaration. - R should be an integer constant expression. - Unlike assert, there is no run-time overhead. - - The implementation uses __LINE__ to lessen the probability of - generating a warning that verify_function_NNN is multiply declared. - However, even if two declarations in different files have the same - __LINE__, the multiple declarations are still valid C89 and C99 - code because they simply redeclare the same external function, so - no conforming compiler will reject them outright. */ +/* Verify requirement R at compile-time, as a declaration. */ # define verify(R) \ - extern verify_type__ (R) GL_CONCAT (verify_function_, __LINE__) (void) + extern int (* verify_function__ (void)) [sizeof (verify_type__ (R))] /* Verify requirement R at compile-time, as an expression. - R should be an integer constant expression. - Unlike assert, there is no run-time overhead. This macro can be used in some contexts where verify cannot, and vice versa. Return void. */ |