Re^2: The weirdest problem with undef

[blazar]

In this case your best bet would be to declare my (@array1, @array2) before the for loop if you want them to be available to your subroutines.

[SNIP]

This clearly tells me that the subroutine is looking for global variables. Declaring them as my inside a loop doesn't create global variables. So moving them to the top, like this, works fine:

OTOH this suggestion, in this form may contribute to suggest the OP to declare all of his own variables at the top of his scripts, which is indeed a bad habit many newbies have, and goes against proper scoping of variables.

I do use stuff like

{
    my $var;
    sub bus {
        $var++;
    }
}

myself, occasionally. But not as an alternative to parameter passing...