Mercurial > hg > octave-lyh > gnulib-hg
changeset 6281:7ca9a453289e
(GL_CONCAT0, GL_CONCAT): Remove.
(verify): Don't use the __LINE__ trick, as it doesn't work in general.
Instead, declare a function that returns a pointer to an array,
and use verify_type__ to declare the size of the array.
Problem and germ of a solution reported by Bruno Haible.
author | Paul Eggert <eggert@cs.ucla.edu> |
---|---|
date | Fri, 23 Sep 2005 17:48:14 +0000 |
parents | 92675ebfe83d |
children | ad1b37bff099 |
files | lib/verify.h |
diffstat | 1 files changed, 9 insertions(+), 19 deletions(-) [+] |
line wrap: on
line diff
--- 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. */