application freezes without crashing (and closing)

[wysota]

i assume by worker thread you mean the signal handler (ie pre- event queue) and gui thread the internal qt signal emission (post event queue)....

No. Threads have nothing to do with signals. It's just you said you were doing something "in a separate thread", so I assumed you were using multiple threads.

[nass]

no i haven't implemented any threads of my own... i was under the impression that among other Qt operations that spawh separate threads, the signalling mechanism would do so too.

[wysota]

Hmm... This may come as a surprise for you, but Qt doesn't spawn threads on its own for any of the tasks it does.

[nass]

ok this goes off topic, but what is the point of libqt-mt then?

[wysota]

That applications built over Qt (like KDE) can spawn their own threads. Qt3 itself can be built without thread support and still have the same functionality (apart from ability to spawn threads of course).