Thread: Re: [BUGS] bug in windows xp

[Re: Uncaught exception when dividing integers]

On Tue, Apr 18, 2006 at 10:50:24PM -0400, Bruce Momjian wrote:
>
> Is anyone working on this?

Not that I know of. However, the first step is to add this regression
test for SIGFPE [-patches CCed]. Note that this will probably redline
windows on the buildfarm. Once this has been added and all
architechures are in compliance, we can deal with the integer overflow
problem.

Triggering a SIGFPE is a bit tricky. On my i386 system the integer
divide will do it, but the rest just return +inf. Given there are
systems that don't SIGFPE the integer divide, I hope one of the others
will trigger... For UNIX systems I've made it try kill() first, that
seems the most reliable.

Have a nice day,
--
Martijn van Oosterhout   <kleptog@svana.org>   http://svana.org/kleptog/
> From each according to his ability. To each according to his ability to litigate.

Martijn van Oosterhout <kleptog@svana.org> writes:
> Not that I know of. However, the first step is to add this regression
> test for SIGFPE [-patches CCed].

This seems completely pointless.  The question is not about whether the
SIGFPE catcher works when fired, it's about what conditions trigger it.

            regards, tom lane

On Wed, Apr 19, 2006 at 10:15:54AM -0400, Tom Lane wrote:
> Martijn van Oosterhout <kleptog@svana.org> writes:
> > Not that I know of. However, the first step is to add this regression
> > test for SIGFPE [-patches CCed].
>
> This seems completely pointless.  The question is not about whether the
> SIGFPE catcher works when fired, it's about what conditions trigger it.

Well, depends how you look at it. The original bug report was about a
backend crash, which is what happens if you don't catch the SIGFPE. Can
we guarentee that we know every situation that might generate a SIGFPE?

Besides, isn't this what you were referring to here:

http://archives.postgresql.org/pgsql-bugs/2006-04/msg00091.php

Otherwise we should just fix int4div.
--
Martijn van Oosterhout   <kleptog@svana.org>   http://svana.org/kleptog/
> From each according to his ability. To each according to his ability to litigate.

Martijn van Oosterhout <kleptog@svana.org> writes:
> Well, depends how you look at it. The original bug report was about a
> backend crash, which is what happens if you don't catch the SIGFPE. Can
> we guarentee that we know every situation that might generate a SIGFPE?

The point here is that under Windows int4div seems to be generating
something other than a SIGFPE --- if it were actually generating that
particular signal then the existing SIGFPE catcher would catch it.

It's barely possible that int4div *is* generating a SIGFPE and there's
some other breakage preventing FloatExceptionHandler from catching it,
but that's a question that deserves a one-shot test, not permanent
memorialization in a regression test.  Besides, if that's the situation
then testing that the handler catches kill(SIGFPE) proves exactly zero
about what the int4div problem is.

            regards, tom lane