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/* 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. */
/* Written by Paul Eggert and Jim Meyering. */
#ifndef VERIFY_H
# define VERIFY_H 1
/* Each of these 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.
There are two macros, since no single macro can be used in all
contexts in C. verify_true (R) is for scalar contexts, where it
may be cast to void if need be. verify (R) is for declaration
contexts, e.g., the top level.
The symbols verify_error_if_negative_size__ and verify_function__
are private to this header. */
/* Verify requirement R at compile-time, as an integer constant expression.
Return true. */
# ifdef __cplusplus
template <int w>
struct verify_type__ { unsigned int verify_error_if_negative_size__: w; };
# define verify_true(R) \
(!!sizeof (verify_type__<(R) ? 1 : -1>))
# else
# define verify_true(R) \
(!!sizeof \
(struct { unsigned int verify_error_if_negative_size__: (R) ? 1 : -1; }))
# endif
/* Verify requirement R at compile-time, as a declaration without a
trailing ';'. */
# define verify(R) extern int (* verify_function__ (void)) [verify_true (R)]
#endif
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