[PyKDE] canvas related segfault

Hans-Peter Jansen hpj at urpla.net
Thu Feb 10 16:12:16 GMT 2005

[resend to the ML, since it is of public interest]

On Thursday 10 February 2005 11:08, Phil Thompson wrote:
> > Hi Phil,
> >
> > there was a nice little qt tile based imaging example published
> > today in the german linux magazine, and I thought, it would be
> > nice to play with in PyQt, thus I converted it. Now it appears,
> > that after loading an image and quitting, it segfaults
> > reproducible, unless I use the WDestructiveClose flag on the main
> > window. Here's a typical backtrace:
> I haven't looked at this in detail, but the comments at the bottom
> of canvas.py in the PyQt examples might be relevant here.

Hmm, none of these lines below app.exec_loop() seems to be needed here 
as everthing is destructed just fine without them. So maybe this 
comment is misleading or outdated. BTW, doesn't that example miss 
some global statements at least?

But you pushed me in the right direction (again): the most interesting 
part of this example is the clear() method: it iterates over all 
canvas items and calls setCanvas(None) before deletimg them. It would 
be nice to make this call transparently in the destructor of canvas 
items to get on par with C++, if possible. At least, I can't find 
such a notion in the Qt canvas.cpp example. If I'm going to do 
something serious with canvases, I would try to fix this myself.


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