/*
 * Copyright (C) 1999, 2000  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 1.8 2000/06/22 21:57:44 tale 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 */
