[PyQt] Best way to pass commands between threads?

[Marc Nations]

On Tue, Mar 17, 2009 at 11:53 AM, Phil Thompson <phil at riverbankcomputing.com
> wrote:

> On Tue, 17 Mar 2009 11:32:48 -0500, Marc Nations <mnations.lists at gmail.com
> >
> wrote:
> > Hi,
> > In the past with other gui toolkits I've set up a periodic call function
> > that pulls control back from the child threads and take care of all the
> gui
> > business that gets originated in the child threads. Either I've stored
> all
> > the commands in a queue to be processed when periodic check is executed
> or
> > used some other technique so that the gui runs the commands from within
> the
> > gui thread and doesn't spit the bit by trying to perform the commands in
> > another thread.
> >
> > Does Qt have a "best accepted" way of handling this? I've read that some
> > use
> > connections to pass control between threads, but I wasn't sure if that's
> > the
> > most efficient way. I basically just need to output text updates to the
> > status window, so I can either queue up the text to be displayed or the
> > calls themselves to be executed later. However if Qt efficiently fires a
> > signal when a certain event happens and fills the slot in the appropriate
> > thread then that sounds like a better approach.
>
> Qt only has one mechanism for communications between threads - events.
> Inter-thread connections are implemented using events.
>
> Use whatever results in the most readable and/or reusable code. Personally
> I'd use signals and slots with the text as an argument, so that the code
> could be reused without threads without being changed.
>
> Phil
>

So will using the threading functionality in Python, independent of the
threading functionality in Qt, cause problems with the execution?

I created a worker thread using the standard Python threading module, so as
a result I can't use it to emit a signal. I can create another class in that
thread (basically a dummy class from QtCore.QObject) and use it to just be a
signal emitter. That's the quickest fix. But if not using the threading
functionality inherent in Qt will cause issues down the road, then I'll need
to rewrite my thread class.

Thanks,
Marc
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