my $incoming = IO::Socket::INET->new( LocalPort => $MSGPORT,
                                      Proto     => 'udp',
                                      Timeout   => 1);

## some more code...

    while ( $incoming->recv( $msg, $MAX_SIZE ) ) {

        my ( $port, $addr ) = unpack_sockaddr_in( $incoming->peername );
        push @messages, [ $addr, $msg ];
        last if @messages > $MAX_INC_Q_SIZE;
    }