usr/src/sys/sys/msgbuf.h

/*
 * Copyright (c) 1981, 1984 The Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms are permitted
 * provided that the above copyright notice and this paragraph are
 * duplicated in all such forms and that any documentation,
 * advertising materials, and other materials related to such
 * distribution and use acknowledge that the software was developed
 * by the University of California, Berkeley.  The name of the
 * University may not be used to endorse or promote products derived
 * from this software without specific prior written permission.
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 *
 *      @(#)msgbuf.h    7.2 (Berkeley) %G%
 */

#define MSG_MAGIC       0x063061
#define MSG_BSIZE       (4096 - 3 * sizeof(long))
struct  msgbuf {
        long    msg_magic;
        long    msg_bufx;
        long    msg_bufr;
        char    msg_bufc[MSG_BSIZE];
};
#ifdef KERNEL
struct  msgbuf msgbuf;
#endif