Re: [[gtkmm] Destroying container problem]

[Olivier Samyn <osamyn ulb ac be>]

Le mar 02/07/2002 à 18:04, Murray Cumming a écrit :
> On Tue, 2002-07-02 at 16:40, Andrew E. Makeev wrote:
> > Murray Cumming wrote:
> > 
> > > "Andrew E. Makeev" <andrew solvo ru> wrote:
> > > > I had Segfault signal on application exit.
> > > > Problem occured in dynamic_cast<> call in following fragment of
> > > > gtkmm/container.cc module:
> > > > ..
> > > > void Container_Class::remove_callback(GtkContainer* self, GtkWidget* p0)
> > >
> > > Please add a complete, simple, compileable example to bugzilla. I solved a
> > > similar problem recently, but then we made some major changes to this stuff
> > > and maybe we've broken it again.
> > >
> > 
> > Unfortunatelly, I couldn't reproduce this one with small example...
> > Staring to guess again, I made something wrong in my original app. It's not so
> > big to explore, but I don't think it's a good idea to waste your time on
> > fixing my code :), is it?
> 
> You need to break it down. I wouldn't do anything that you couldn't do,
> until you discover something that you think is a gtkmm bug.
> 

I had a similar problem when using a timer in one of my application...
I seems there is a concurency access problem when deleting objects.

After some try I think I found the problem. It comes with SigC+++ slots.

In my program I used: 
-------------------------------------------------------------------------
MainWindow::MainWindow ()
{
 ....
 Gtk::EventBox *eventbox = manage (new Gtk::EventBox());
 mouseHandler = new MouseHandler(this);
 eventbox->signal_motion_notify_event().connect( 
   slot(*mouseHandler, &Fract::MouseHandler::cursorMove));
 eventbox->set_events(eventbox->get_events()|
   Gdk::POINTER_MOTION_MASK);
 ....
};

MainWindow::~MainWindow ()
{
  ...
  delete mouseHandler;
  ...
};
-------------------------------------------------------------------------
It seems the problem comes with SigC++. When you're closing the
application and you mouse is moving the mouseHandler is already
destroyed and is called by the previous binding.

The solution is to replace the new/delete part with:

 mouseHandler = manage(new MouseHandler(this));

This solved my problem... I think (don't verifyed) before deleting an
object SigC++ unbind all binded objects functions...

Another solution is maybe doing an unbind your self. But I don't tried
this.

Oleastre