1/* Compile-time assert-like macros. 2 3 Copyright (C) 2005 Free Software Foundation, Inc. 4 5 This program is free software; you can redistribute it and/or modify 6 it under the terms of the GNU General Public License as published by 7 the Free Software Foundation; either version 2, or (at your option) 8 any later version. 9 10 This program is distributed in the hope that it will be useful, 11 but WITHOUT ANY WARRANTY; without even the implied warranty of 12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 GNU General Public License for more details. 14 15 You should have received a copy of the GNU General Public License 16 along with this program; if not, write to the Free Software Foundation, 17 Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ 18 19/* Written by Paul Eggert and Jim Meyering. */ 20 21#ifndef VERIFY_H 22# define VERIFY_H 1 23 24/* Each of these macros verifies that its argument R is a nonzero 25 constant expression. To be portable, R's type must be integer (or 26 boolean). Unlike assert, there is no run-time overhead. */ 27 28/* A type that is valid if and only if R is a nonzero constant expression. 29 The symbols verify_type__ and verify_error_if_negative_size__ are 30 private to this header file. */ 31 32# define verify_type__(R) \ 33 struct { unsigned int verify_error_if_negative_size__ : (R) ? 1 : -1; } 34 35/* Verify requirement R at compile-time, as a declaration. */ 36 37# define verify(R) \ 38 extern int (* verify_function__ (void)) [sizeof (verify_type__ (R))] 39 40/* Verify requirement R at compile-time, as an expression. 41 This macro can be used in some contexts where verify cannot, and vice versa. 42 Return void. */ 43 44# define verify_expr(R) ((void) ((verify_type__ (R) *) 0)) 45 46#endif 47