If they are in the same file using my will work, as long as it isn't in an enclosing block.

my $i = 10;
&print_i;

sub print_i{
    print "$i\n";
}
[download]

If they aren't in the same file then our is the way to go
File1:

our $i = 10;
....
[download]

File2:

our $i;
...
sub print_i{
    print "$i\n";
}
[download]

- Tom