Does Qt creates any thread(Besides main thread in single threaded GUI program) for responding to OS generated Events?

[blue_sky]

There is some Concepts like Event Queue/Event loop for Queuing the Events and proceeding one after another.If there is an extra thread to respond OS events, no problem to make a Event Queue and dispatch one by one when main thread will finish one task(executing set of codes after an event).
But what’s the scenario if only one thread is present?
Please take a look at flow asked in a Question
http://stackoverflow.com/questions/16812602/qt-main-gui-and-other-thread-events-loops
—and help me.