On Tue, Mar 01, 2005 at 11:43:31AM +1100, Andrew Savige wrote:
> running this Perl program:
>
> use strict;
> sub div_by_zero { exec("./a.out $_[0]"); die "should not be here" }
> defined(my $pid = fork()) or die "fork: $!";
> if ($pid == 0) {
> warn "child, my pid $$\n";
> div_by_zero(0); # sig 8
> # div_by_zero(); # sig 11
> exit;
> }
> warn "parent, my pid $$\n";
> waitpid($pid, 0);
> my $rv = $? >> 8;
> my $sig = $? & 127;
> warn "$$: rv=$rv sig=$sig\n";
>
> produces:
>
> parent, my pid 12091
> child, my pid 12092
> 12091: rv=0 sig=8
>
> Replacing div_by_zero() above with:
>
> sub div_by_zero { 5 / shift }
>
> produced:
>
> parent, my pid 12133
> child, my pid 12134
> Illegal division by zero at g2.pl line 2.
> 12133: rv=255 sig=0
>
This is not related to the original topic, but I've always
wondered this: In math a number divided by 0 is "undefined". Why is it
that in a language which has an undefined value does the interpreter
poop out rather than just having the intuitively obvious behavior of
returning undef? Is that really by design, or just a legacy quirk they're
afraid to fix?
Austin
