my $msgs = {    '200'   =>  'OK',
                '400'   =>  'Bad Request',
                '403'   =>  'Forbidden',
                '404'   =>  'Not Found',
                '500'   =>  'Internal Sever Error',
            };

sub msg {
    print "HTTP/1.0 $_[0] $msgs->{$_[0]}\n";
}

if (1 == 1) {
    msg(400);
}