Undefined subroutine &main::guid called at H:\bin\foo.pl line 11.

##</code><code>##

use Guid;
print "Guid = " . guid() . "\n";

##</code><code>##

use Guid qw(guid);
print "Guid = " . guid() . "\n";

##</code><code>##

use Guid;
print "Guid = " . Guid::guid() . "\n";

##</code><code>##

package Guid;
use strict;
use warnings;

use Math::BigInt;
use Net::Address::Ethernet qw(get_address);

BEGIN {
    use Exporter ();
    our ($VERSION, @ISA, @EXPORT, @EXPORT_OK, %EXPORT_TAGS);
    $VERSION = 1.00;
    @EXPORT = qw(guid);
    %EXPORT_TAGS = ();
}


sub guid {
    my ($clockId, $netId) = $_;

    my $maxClockId = 2**14;
    my $clockIdOffset = 2**15;  #Turn on Clock High bit
    my $timeOffset = "122192928000000000";
    [...And On...]