/* 2 Jul 1991 by Eric Grosse.  Copyright (c) 1991 by AT&T.
 * Permission to use, copy, modify, and distribute this software for any
 * purpose without fee is hereby granted, provided that this entire notice
 * is included in all copies of any software which is or includes a copy
 * or modification of this software and in all copies of the supporting
 * documentation for such software.
 * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR IMPLIED
 * WARRANTY.  IN PARTICULAR, NEITHER THE AUTHORS NOR AT&T MAKE ANY
 * REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE MERCHANTABILITY
 * OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR PURPOSE.
 */

/* Tested only on IRIX 3.3.2.  May need modification for other systems.
 * We assume memory is laid out, in order of increasing addresses, as
 *	shared memory segments
 *	global variables
 *	sbrk
 *	stack
 */

#include <ctype.h>
#include <stdio.h>

int isshm_junk;

/* returns non-0 if p points into shared memory segment */
int
isshm(char* p)
 /* p should either point to the beginning of the data area of a shared
	memory segment, or to someplace in the stack or malloc arena. */
{
	if( p > &isshm_junk )
		return(0);
	if(!isdigit(*(p-128))){
		/* should have seen first digit of shmid */
		fprintf(stderr,"inconsistency discovered in isshm\n");
		abort();
	}
	return(1);
}