#!/usr/bin/perl -w use strict; package joe; my @names = ('joe', 'aaron'); package FP; sub sortNames ($$) { print "$_[ 0 ] vs $_[ 1 ]\n"; return $_[ 0 ] cmp $_[ 1 ]; } package joe; my @sorted = sort nonexistent @names; print "sorted : @sorted\n"; CHECK {print "here I am\n"} __END__ here I am Undefined subroutine in sort at asort.pl line 15.