[wxPython-users] Re: Segmenation fault when exiting app

[Robin Dunn]

Franz Steinhäusler wrote:
> On Tue, 24 Apr 2007 10:45:40 -0700, Robin Dunn <robin at alldunn.com> wrote:
> 
>> Franz Steinhaeusler wrote:
>>
>>> Sorry for getting a little OT.
>>> Is there anything else (I don't know gdb so good) to extract even more information.
>>>
>>> the backtrace is not the stack, isn't it.
>> It shows the C++ call stack, but not the data values on the stack.
> 
> Ok.
> 
> Meanwhile I could figure out the culprit. :) 
> 
> In easy words:
> 
> (It happens only on gtk, windows seems to be more "robust" in that way or handles this in another way.

It's probably a difference of the order events are being sent, or if 
they are sent at all during shutdown.

> 
> If I'm wrong, please correct me
> When the Program exits, the frame is being destroyed.
> In the run of this procedure, the notebook tabs are destroyes, and in that process, event page changed is called.
> In the procedure of the pageeventchanged, the statustext was updated via SetStatusText of the frame.
> That lead to a segmentation fault. I looked how to check, if the frame is "valid". I found the promising function IsBeingDeleted
> and applied it that way:
> 
> in OnNotebookTabChanged:
>         if not self.grandparent.IsBeingDeleted():
>             self.grandparent.txtDocumentArray[i].OnModified(None) 
> 
> 		#in that function, the status bar is updated;   
>        #self.grandparent.txtDocumentArray[i] is a styled text control.
> 
> 
> Would you solve that in another way or is it right so?

Yes, that looks correct.  You could probably also check either of these 
conditions:

	if self.grandparent:
		...

	if not self.IsBeingDeleted():
		...

-- 
Robin Dunn
Software Craftsman
http://wxPython.org  Java give you jitters?  Relax with wxPython!