I said it was trivial:)

#! perl -slw
use strict;
use threads;
use threads::shared;

my @myarray : shared;
sub pid { lock @myarray; push @myarray, $_[ 0 ]; }
threads->new( \&pid, $_ )->detach for 1 .. 3;
sleep 2;
print "@myarray";
__END__
[23:30:52.15] P:\test>417163
1 2 3
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