title: Is there a way to check if a QObject-pointer is still valid in Qt?
body: <p>I have a scenario where an anonymous <code>QObject</code> starts an asynchronous operation by emitting a signal. The receiving slot stores the QObject-pointer and sets a property of this object later. The object could be gone meanwhile. </p>
  
  <p>So, is there a safe way to check if this pointer still valid?</p>
  
  <p>P.S.:
  I'm aware of <code>QObject::destroyed</code> signal, which I could connect to the object supposed to call the <code>setProperty</code> of that pointer. But I wonder, if it works easier.</p>