#!/usr/bin/perl 
use strict;
use warnings;
use Data::Lock qw(dlock);

my @folks = qw(larry curly moe);
dlock(\@folks);

eval { 
    shift @folks; 
    print "removed larry\n"; 
} or warn $@;

eval { 
    $folks[2] = 'joe';
    print "replaced moe\n"; 
} or warn $@;