QThread confusion, yet another question about quiting thread

[franz]

I would like to know why when I use
connect( th, SIGNAL(started()), this, SLOT(threadStarted()));
the function in this SLOT is run but thread don't seams to react properly (is it because the SLOT is in the same Thread as the QThread, with is GUI thread?).

Absolutely. connections can be autodetected, queued or direct. If they're directly connected, the slot is executed in the emitting thread, if they're queued the slot is executed in the thread its class lives in. In this case QThread did emit started(), but QThread lives in the main thread, just like your MainWindow. No reason to perform the threadStarted() function in a different thread there.