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From: wrp@krebs.acc.virginia.edu (Wm Pearson)
Newsgroups: comp.unix.xenix
Subject: SCO Xenix 'C' pointer bug
Message-ID: <227@krebs.acc.virginia.edu>
Date: Tue, 25-Aug-87 15:20:15 EDT
Article-I.D.: krebs.227
Posted: Tue Aug 25 15:20:15 1987
Date-Received: Thu, 27-Aug-87 06:24:19 EDT
Organization: School of Medicine, University of Va.
Lines: 37


	Attached is a test program which displays a bug I just found
in the SCO 'C' development system 2.1.4 release G.  Compile the
program and run it.  You will find the value of 'dpos' goes up to 3999
just fine, but then becomes negative.  I would appreciate a work-around
that does not require a division by sizeof(struct tstruct). Note
that although the pointers are being treated as ints (intead of unsigned)
in the expression (int)(dptr-diag), they are being treated properly in
the 'dptr<&diag[5000].

============= test.c
Bill Pearson
wrp@virginia.BITNET
...!seismo!virginia!wrp


#include <stdio.h>

struct tstruct {
	int one;
	int two;
	int three;
	int four;
	} *diag, *dptr;

main()
{
	char *calloc();
	unsigned int dpos;
	
	diag = (struct tstruct *)calloc(5000,sizeof(struct tstruct));
	for (dptr=&diag[99]; dptr<&diag[5000]; dptr +=100) {
		dpos = (unsigned int)(dptr-diag);
		printf("%4d %4d\n",dpos,(int)(dptr-diag));
	}
}
=============