Re: division by zero

"Eric B. Ridge" <ebr(at)tcdi(dot)com> writes:
> select 1/0; fails as expected on my x86 Linux box, so yer right, it's
> just my little Mac. "I switched because Mac's can divide by zero."

I checked into this, and indeed OS X 10.2 is behaving funny: integer
divide by zero doesn't raise any signal, it just returns a bogus answer.
They're within their rights to do so according to the ANSI C spec
(wherein division by zero is stated to have undefined behavior).
But since other BSD-derived Unixen all seem to raise SIGFPE, I can't
help wondering if this shouldn't be considered a bug.

I think we have three possible responses:

1. Put explicit tests for zero into the integer division SQL function
routines.

2. Consider this Apple's problem and file a bug report.

3. Both.

I don't care for answer #1 alone, because it would only catch zero
divides in the specific places we put in tests; internal errors would
likely go uncaught. So I think a complaint to Apple is in order.
I'm not sure whether to also put in zero-divide guards. Comments?

regards, tom lane