code: @Override
  	public final void close()
  	{
  		try {
  			if (fd != INVALID_HANDLE)
  				close0();
  		}
  		catch (final IOException e) {
  			logger.error("closing serial port", e);
  		}
  		fd = INVALID_HANDLE;
  	}
docs: any open input/output stream accessing this port becomes unusable