#!/usr/bin/perl
use strict; 
use warnings;

my ($foo, $bar);

print '1: ', $foo eq $bar, "\n";    # Uninitialized warning. 
{ 
    no warnings qw( uninitialized ); 
    print '2: ', $foo eq $bar, "\n";    # No warnings emitted.
}

print '3: ', $foo eq $bar, "\n";    # Warns again.