[PyKDE] Crashing problems, suggestions?

Matt Newell newellm at blur.com
Thu Mar 1 22:12:46 GMT 2007

On Thursday 01 March 2007 12:36, Kevin Cureton wrote:
> Since I converted my application from PyQt3 to PyQt4, I've run into
> some issues with the threading.
> I ran into the deadlock problems a while back and managed to avoid it
> by only sending signals from QThreads to the main thread. The main
> thread, instead of sending signals or events to the QThreads, would
> instead hand them work via a thread-safe queue I wrote. Doing that
> avoided the deadlock problem but appeared to uncover another issue.
> Consistent crashes.
> I'm not going to claim this is a PyQt or Qt issue. It could very well
> be my failure to protect some resource with a mutex. However, after
> various attempts over the past month, I need to take some focused
> time and resolve this issue. I've attached a crash trace. We are
> running the application on both Mac and Linux and similar results
> (though I don't have a Linux trace available currently).
> I'm looking for some ideas on how to approach debugging this problem
> (or web pages that can help). I'm hoping to create a small, scoped
> test case that demonstrates this problem and get that sent to the
> list. Until then, any ideas or thoughts on how to proceed would be
> greatly appreciated.
> I am currently running Qt 4.2.2, and the sip and PyQT4 snapshots from
> 20070227 on both a Powerbook (PPC, 10.4.8) and a Mac Pro (Intel,
> 10.4.8).
> --kev

What kind of data structures are you using in your worker thread?  I was 
having some stability issues with implicitly shared( via reference counting ) 
database classes that were being loaded in a worker thread.  I was able to 
fix them by using QBasicAtomic instead of an int for reference counting.  May 
not be at all relevant to your situation, but something to think about.


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