Autzoo.1633
net.bugs.v7
utzoo!henry
Tue May  4 22:02:15 1982
overflow in C revisited
Very entertaining things can happen with integer overflow in C.  This
isn't really a bug, except that (as reported some months ago) the
manual should say the effects of overflow are "undefined" instead of
saying that it is "ignored".  Consider the following:

-----
/*
 * Arithmetic in the presence of overflow is context-dependent in
 * very strange ways.
 */

unsigned int compile = (56*1024)/64;

main()
{
	printf("%u == %u\n", compile, (56*1024)/64);
	printf("%u == %u == %u (!!)\n", compile, 57734/64, (56*1024)/64);
}
-----

Can you guess what this prints?  Like this:

	65408 == 65408
	65408 == 0 == 902 (!!)

Yes, friends, it's context-dependent!