title: Answer an UDP packet
body: <p>I have a UDP server using the following code:</p>
  
  <pre><code>void initialize() 
  {
      connect(&amp;_udpSocket, SIGNAL(readyRead()), this, SLOT(onUdpDatagram()));
  
      _udpSocket.bind(QHostAddress::Any, 28283);
  }
  
  void onUdpDatagram()
  {
      qDebug() &lt;&lt; "udp packet received!";
      _udpSocket.write("Hello");
  }
  </code></pre>
  
  <p>Unfortunately when a UDP packet is received, I have the following error in the log:</p>
  
  <pre><code>QIODevice::write: device not open
  </code></pre>
  
  <p>How can I make the UDP socket writable? I tried to create another socket for the answer that connect to the sender address and port but the sending won't use the 28283 port anymore...</p>
  
  <p>Any idea?</p>
  
  <p>For info: I'm using Qt 5.2.1 on MacOS 10.9</p>