#!/usr/bin/perl 

use strict;
use warnings;

my $INTERRUPT_MESSAGE = "caught sig int user interrupt";
$SIG{'INT'} = sub { die $INTERRUPT_MESSAGE };

my $login = new CQLogin();

my $username = eval { $login->autoLogon() };
if ( !defined $username && $@ ) {
    print STDERR "wow, we got a signal\n\n"; #just for demo purpose
    die $@ unless $@ eq $INTERRUPT_MESSAGE;
}
print "Success, our username is [$username]\n\n";

#note, username will be undef if the user interrupted.

package CQLogin;

sub new
{
    my $class = shift;
    return bless {}, $class;
}

sub autoLogon
{
    my $self = shift;
    chomp( my $username = <STDIN> );
    return $username;
}