Path: utzoo!attcan!uunet!cs.utexas.edu!asuvax!ncar!tank!gargoyle!ddsw1!olsa99!zeusa!hendrik
From: hendrik@zeusa.UUCP (Hendrik Vermooten)
Newsgroups: comp.lang.c
Subject: DEFINITE bug in Turbo C 2.0
Message-ID: <802@zeusa.UUCP>
Date: 22 Mar 90 07:21:31 GMT
Organization: ZEUS software, Verwoerdburg
Lines: 40

Here is a definite bug in C (discovered by Renier v. Wyk)

(Please, no speeches about not using ++a etc in a macro :-) I've never
 done it, and never plan to do it. Interesting bug, nonetheless)

#include <stdio.h>
#define SQR(a) a*a
main ()
{
	int a = 10, b = 10, x, y;

	x = SQR (++a);
	y = SQR (b++);
	printf ("%d\n", x);
	printf ("%d\n", y);
	a = 10;
	b = 10;
	printf ("%d\n", SQR (++a));
	printf ("%d\n", SQR (b++));
}

Run by Turbo C it gives:

144
100
132
110

And run by Microsoft C (under XENIX):

132
110
132
110

 *** ***     Hendrik Vermooten, ZEUS software
 * o o *     Bang: ..!uunet!ddsw1!olsa99!zeusa!hendrik
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