Main thread - worker thread communication.

[wysota]

But isn't the whole idea ?? In C# we use delegates to do that, in Qt i hoped that with Signals and Slots i will be able to do it. I think that Qt automatically find the correct thread to "use".

Yes, but I'm not sure what it will decide when you call a function from an object that lives in another thread. It might work, but I'm not sure, therefore I used this kind of "proxy".

Your Emiter class is "translated" to Python like this ?

class Emiter(QtCore.QObject):
    def __init__(self):
        QObject.__init__(self)
 
    def emitSignal(self, val):
        self.emit(QtCore.SIGNAL("updateProgress"), x)

class Emiter(QtCore.QObject):
    def __init__(self):
        QObject.__init__(self)
    
    def emitSignal(self, val):
        self.emit(QtCore.SIGNAL("updateProgress"), x)

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Looks correct.

And what is the purpose (and implementation as it is not shown how it does it's work) of MyThread:: propagate ? Just to forward the signal ?

Yes, just to forward the signal. As I mentioned, you could do it without it, but then you'd have to have access to the progress bar from within the thread object. That's your choice.