[PyQt] QMainWindow bug?

[Mailing List SVR]

Il giorno gio, 20/01/2011 alle 10.57 +0100, Antonio Valentino ha
scritto:
> Hi Nicola,
> 
> Il giorno Thu, 20 Jan 2011 10:22:55 +0100
> Mailing List SVR <lists at svrinformatica.it> ha scritto:
> 
> > Ok, in a my pyqt app (I'm still using pyqt-4.7.x), I have a dialog
> > that require much time to open so I keep a reference to it in a app
> > global variable and I use this reference to reopen the dialog after
> > the first time. This seems to work and the dialog open much quicker,
> > however in some undeterminated cases I get:
> > 
> > RuntimeError: underlying C/C++ object has been deleted
> > 
> > when I get this error I recreate the dialog and update the global
> > reference,
> > 
> > can you please explain the right way to keep a reference in python to
> > a qt object?
> 
> One way could be to explicitly reset the global variable
> 
> global_dialog = None
> 
> before application shutdown (e.g in QMainWindow.closeEvent)

thanks Antonio,

my problem is not the segfault on shutdown, I want to keep an object in
memory so I can reuse it, the method explained in my previous mail works
99% of the times, sometime I get:

RuntimeError: underlying C/C++ object has been deleted

do you know a way to avoid that qt delete an object (apart keep a
reference to it as explained in my previous mail)?

Nicola

> 
> regards
> 
> 
> > thanks
> > NIcola
> > 
> > 
> > Il giorno mer, 19/01/2011 alle 23.47 +0100, Erik Janssens ha scritto:
> > > there was a change in sip/pyqt from 4.8.1 to 4.8.2 regarding
> > > the detection of objects deleted by qt but still referenced in
> > > python (which is the case here).  in 4.8.1 sip/pyqt tried to
> > > detect this to avoid segfaults.  this detection however brought
> > > other issues with it, therefor the detection was turned off again
> > > in 4.8.2
> > > 
> > > the solution is not to keep references in python of objects
> > > owned by qt when they might get deleted.
> > > 
> > > On Wed, Jan 19, 2011 at 12:36 PM, Mailing List SVR
> > > <lists at svrinformatica.it> wrote:
> > > > I can confirm the segfault:
> > > >
> > > > - linux, kernel 2.6.36
> > > > - python 2.7.1
> > > > - pyqt 4.8.2
> > > > - qt 4.7.1
> > > >
> > > > works fine with PySide,
> > > >
> > > > Nicola
> > > >
> > > >
> > > > Il giorno mer, 19/01/2011 alle 08.36 +0100, Vicent Mas ha scritto:
> > > >> 2011/1/18 Nick Gaens <mail at nickgaens.com>:
> > > >> > - Win7 64bit
> > > >> > - Python 2.6.6 (r266:84297, Aug 24 2010, 18:46:32) [MSC v.1500
> > > >> > 32 bit (Intel)] on win32
> > > >> > - Qt v4.7.0
> > > >> > - PyQt GPL v4.8.1 for Python v2.6
> > > >> > Result: no crashes, works like a charm..
> > > >> >
> > > >>
> > > >> Hi,
> > > >>
> > > >> I get the crash also on Windows Vista 32bit (again Python 2.6
> > > >> and PyQt 4.8.2)
> > > >>
> > > >> Vicent
> 
> 
>