lock = new Object();
    }
    public int read() throws IOException {
        int result = -1;

        synchronized( lock ) {
            try {
                while( used == 0 ) {
                    lock.wait();
                }
            } catch( InterruptedException ie ) {
                throw new IOException( ie.getMessage() );
            }
            result = pipe_buf[beg_idx] & 0xFF;