From cfdfe3e3184657f1f414fef6054d2aba0e93badd Mon Sep 17 00:00:00 2001 From: Jim Meyering Date: Mon, 4 Jul 2005 16:05:41 +0000 Subject: (verify, verify_dcl): New file/macros. --- lib/verify.h | 43 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 43 insertions(+) create mode 100644 lib/verify.h diff --git a/lib/verify.h b/lib/verify.h new file mode 100644 index 000000000..013ed84f8 --- /dev/null +++ b/lib/verify.h @@ -0,0 +1,43 @@ +/* Compile-time assert-like macros. + + Copyright (C) 2005 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 + the Free Software Foundation; either version 2, or (at your option) + any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software Foundation, + Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ + +#ifndef VERIFY_H +# define VERIFY_H 1 + +# ifndef verify_dcl +# define GL_CONCAT0(x, y) x##y +# define GL_CONCAT(x, y) GL_CONCAT0 (x, y) + +/* Verify requirement, R, at compile-time, as a declaration. + The implementation uses a struct declaration whose name includes the + expansion of __LINE__, so there is a small chance that two uses of + verify_dcl from different files will end up colliding (for example, + f.c includes f.h and verify_dcl is used on the same line in each). */ +# define verify_dcl(R) \ + struct GL_CONCAT (ct_assert_, __LINE__) { char a[(R) ? 1 : -1]; } +# endif + +/* Verify requirement, R, at compile-time, as an expression. + Unlike assert, there is no run-time overhead. Unlike verify_dcl, + above, there is no risk of collision, since there is no declared name. + This macro may be used in some contexts where the other may not, and + vice versa. Return void. */ +# undef verify +# define verify(R) ((void) sizeof (struct { char a[(R) ? 1 : -1]; })) + +#endif -- cgit v1.2.3-70-g09d2