Sorry if I misunderstand what you say
What vars does is declare a certain global in a certain package so that strict will not complain about it. If you have a package that crosses files, the declaration will cover both (assuming it happens in the first one Perl compiles).
foo.pl 
#!/usr/bin/perl
use strict;
use warnings;
package Foo;
use Bar;

our $one;
our $two;

use vars qw($three $four);

$one = 'one';
$two = 'two';
$three = 'three';
$four = 'four';

print "$one $two $three $four\n";

Foo::switch();

print "$one $two $three $four\n";

[download]
Bar.pm 
#!/usr/bin/perl
use strict;
use warnings;
package Foo;

our $one;
our $two;

use vars qw($three $four);


sub switch {
    $one = 1;
    $two = 2;
    $three = 3;
    $four = 4;
    }
1;

[download]
result 
[sandy][~] perl foo.pl
one two three four
1 2 3 4

[download]
I'm not sure I see the difference between our and use vars

UPDATE

Thank you ikegami. Now I get it.

In reply to Re^13: the "our" declaration ?!! (special vars) by Sandy
in thread the "our" declaration ?!! by perlpal

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