TApplication.Destroy calls ProcessAsyncCallQueue
lazarus / 8-Other

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Hansi · 2009-01-03 17:43

Hi!

I'm working on a multi-threaded application which also utilizes
QueueAsyncCall (instead of Synchronize).

If I close the application window while an event is in this
asynchronous queue, an exception occurs.

After some investigations I found the problem to be that
TApplication.Destroy calls ProcessAsyncCallQueue. When closing the
window, all widgets are Destroy()ed. After that, TApplication.Destroy
is executed. This calls ProcessAsyncCallQueue which executes the
events in the asynchronous queue. Since these are class methods of
objects, which have been destroyed before (or refer to such), this is
a problem.

So, my question is: is there a problem in my application setup or is
the problem in the LCL? How can I solve this problem?

Thanks
  Hansi

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Marc · 2009-01-04 02:24

This is always tricky.

In the mainform.OnClose, terminate your threads and make sure the
queue is empty.