freebsd-dev/contrib/ntp/include/isc/magic.h
2004-07-20 15:01:56 +00:00

41 lines
1.4 KiB
C

/*
* Copyright (C) 1999-2001 Internet Software Consortium.
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM
* DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL
* INTERNET SOFTWARE CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT,
* INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING
* FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
* NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
* WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
/* $Id: magic.h,v 1.11 2001/01/09 21:57:10 bwelling Exp $ */
#ifndef ISC_MAGIC_H
#define ISC_MAGIC_H 1
typedef struct {
unsigned int magic;
} isc__magic_t;
/*
* To use this macro the magic number MUST be the first thing in the
* structure, and MUST be of type "unsigned int".
*
* The intent of this is to allow magic numbers to be checked even though
* the object is otherwise opaque.
*/
#define ISC_MAGIC_VALID(a,b) (((a) != NULL) && \
(((const isc__magic_t *)(a))->magic == (b)))
#define ISC_MAGIC(a, b, c, d) ((a) << 24 | (b) << 16 | (c) << 8 | (d))
#endif /* ISC_MAGIC_H */