title: Wait for several objects to emit a signal
body: <p>I know how to wait for a single object to finish, using</p>
  
  <pre><code>QEventLoop eventLoop;
  connect(&amp;obj, SIGNAL(finished()), &amp;eventLoop, SLOT(quit()));
  eventLoop.exec();
  </code></pre>
  
  <p>But now I have several objects which I want to 'run' in parallel, so I need to wait until all of them have sent their <code>finished()</code> SIGNALs.</p>
  
  <p>This would be like a signals-and-slots version of the WaitForMultipleObjects WinApi function.</p>
  
  <p>How should I go about doing that?</p>