use strict;
use warnings;

package B;

our $foo = 3;

package main;

print "foo is >$foo<\n";
__END__
foo is >3<
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as opposed to use vars:

use strict;
use warnings;

package B;
use vars qw($foo);
$foo = 3;

package main;

print "foo is >$foo<\n";
__END__
Global symbol "$foo" requires explicit package name at - line 10.
Execution of - aborted due to compilation errors.
[download]

_($_=" "x(1<<5)."?\n".q·/)Oo.  G°\        /
                              /\_¯/(q    /
----------------------------  \__(m.====·.(_("always off the crowd"))."·
");sub _{s./.($e="'Itrs `mnsgdq Gdbj O`qkdq")=~y/"-y/#-z/;$e.e && print}