title: QObject (QPlainTextEdit) & Multithreading issues
body: <p>Im currently trying to learn Networking with Python asyncore and pyqt4.</p>
  
  <p>I coded a small server, which basically listens on some port, and resends all messages it recieves to the sender.</p>
  
  <p>Since both qts <code>QApplication.exec_()</code> and <code>asyncore.loop()</code> are functions which never return i could not start them both in one thread, so i stared <code>asyncore.loop()</code> in a seperate daemon thread.</p>
  
  <p>Whenever my server class (derived from <code>asyncore.dispatcher</code>) establishes or drops a connection, or sends/recieves a message, it calls methods of my  window class (derived from <code>QtGui.QMainWindow</code>), which displays the information in a <code>QPlainTextEdit</code>.</p>
  
  <p>But the text is not visible, unless you mark the text with the mouse.</p>
  
  <p>Python console displays following error msg:</p>
  
  <pre><code>QObject::connect: Cannot queue arguments of type 'QTextBlock'
  (Make sure 'QTextBlock' is registered using qRegisterMetaType().)
  QObject::connect: Cannot queue arguments of type 'QTextCursor'
  (Make sure 'QTextCursor' is registered using qRegisterMetaType().)
  </code></pre>
  
  <p>I read on some forum, that this may be caused by calling qt-functions from another Thread, and that using signals &amp; slots instead of plain function calling may fix the issue, but i have tried signals aswell, and i still get this error.</p>
  
  <p>So, (if that is really the cause of my problems) whats the correct way to call methods of an qt object from another thread ?</p>
  
  <p><strong>EDIT More Info:</strong>
  the asyncore.loop() call is located in the child thread, well its not really blocking, but only during the runtime of asyncore.loop() my Server class (asyncore.dispatcher) can do networking.
  So, during the runtime of asyncore.loop() the methods of my Server class ARE called by asyncore.loop() (=child thread), and in these i 
  tried to emit signals to the window class running in the main thread</p>
  
  <p><strong>EDIT:</strong> Seems like i got it working now, i had some errors in my code, everything works as intended with signals now.</p>
  
  <p><s><strong>EDIT:</strong> small example: <a href="http://paste2.org/p/635612" rel="noreferrer">http://paste2.org/p/635612</a></s> (dead link)</p>