[PyQt] Threads with PyQt. Qt's or Python's?
chrislb at gmx.de
Tue Jan 20 04:08:58 GMT 2009
Am Tuesday, 20. January 2009 schrieb Giovanni Bajo:
> On 1/19/2009 4:36 PM, Christoph Burgmer wrote:
> > I am doing a
> > QCoreApplication.postEvent()
> > out of "run()" from a "threading.Thread" class without any problems.
> That's only because you are lucky. It's not something that's officially
> supported and I have spent days debugging random crashes that turned out
> being Qt accesses from threads allocated by Python.
> I suggest you to fix your code.
We have an unlucky situation here, Qt documents neither say that mixing
threading libraries is ok, nor does it say it could lead to clashes.
Now guessing won't help, but I'll do it anyway:
QCoreApplication::postEvent() is "thread-safe" and thus has the highest safety
level one could whish for in the Qt threading system. It works by adding the
event to the event queue and returning immediatelly.
It's the main event loop that then takes over.
Now from that I would assume the only clashes could occur when fiddeling with
the event queue. Instead of assuming some magic done in every thread I rather
believe that synchronisation is done in the local method, postEvent(). Now
things going wrong would mean that synchronisation there does depend on the
threads all adhering to the same special protocol, something that IMHO is not
needed to complete this task.
Anyway, if somebody should have a bit more indepth knowledge on that, please
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