Because you mentioned C++, I should mention that memory mangement is IMHO easier and more C++-like with gtkmm. Murray Cumming www.murrayc.com murrayc@xxxxxxx > -----Original Message----- > From: gtk-list-admin@xxxxxxxxx > [mailto:gtk-list-admin@xxxxxxxxx] On Behalf Of The Surprises > Sent: Montag, 19. Januar 2004 01:22 > To: Graham Swallow > Cc: gtk-list@xxxxxxxxx > Subject: Re: Destroying widgets properly > > > Thanks for the feedback. I still can't get it to work. I've > tried numerous combinations of actions with same results. > I've read that you might have to hide() the widget before > destroying it to to turn off all events. Tried it. Doesn't > work. This is frustrating! > > On Sun, Jan 18, 2004 at 07:54:47PM +0000, Graham Swallow wrote: > > Me too. > > > > My framework is libs_apps_YEAR-MM_DD.tgz at > > http://homepage.ntlworld.com/information-cascade/baks/ > > The gtk code is in src/lib_base2/gtk_1/ > > > > I think I fixed my problem by realising that GTK destroys its > > own widget, THEN tells with the "destroy" callback, so that > > C++ can release its storage WITHOUT REFERRING TO GTK > > > > The GTK widget object's memory has been free()d, but you are > > still using it, which either reports "not a valid object", > > or corrupts indirect memory, and the program trips up LATER. > > > > When an upper container is deleted, its children get > AUTO deleted, > > so you must avoid deleting them, but delete the C++ objects. > > > > I also had an issue with signal_disconnect_by_data(). > > I'd claim it still happens, but have stopped calling it (leak). > > > > -OR- > > > > An alternative phase I went through, was when C++ deleted its > > object, when the GTK object is fully alive. > > > > Then GTK calls back, with the deleted objects pointer > > ... chaos ... > > > > -Different ways- > > > > Different designs require opposite senses. Should your code > > delete the widget before or after GTK? Do you tell it, or > > does it tell you? > > > > Reference counts can split widget deconstruction into > > two halves. The DISPLAYED widgets reduction to a skeleton, > > and later free(widget), with the C++ objects delete somewhere. > > > > I do tend to NOT do a refcount on GTK objects, even > though I keep > > a pointer to them. My excuse is that I should not have received > > a "1" count in the first place, which gets absorbed by the PACK > > action (ASIDE check how TCL does this - it's magically sensible, > > and NOT how Python does it). So I do nothing (and it now works). > > > > > > Graham > > Information-Cascade (at) ntlworld.com > > > > > > > Message: 1 > > > Date: Sun, 18 Jan 2004 00:42:46 -0800 > > > From: The Surprises <thesurprises1@xxxxxxxxxxx> > > > To: gtk-list@xxxxxxxxx > > > Subject: Destroying widgets properly > > > > > > Hello, > > > I am getting mysterious and inconsistent crashes in my > gtk program > > > (ie it isn't crashing in the same spot every time), and I > believe it > > > has something to do with how I am destroying a set of widgets. I > > > have an hbox (HB) packed into a vbox (VB). HB has many widgets > > > packed inside of it, most of which are also created/maintained in > > > their own C++ classes. One of the widgets is a > GnomeCanvas, and it > > > itself has many GnomeCanvasItem children, nearly each > maintained in > > > seperate C++ classes as well. At times, I need to > entirely remove > > > HB and all of it's children including the canvas and all of it's > > > children. I then recreate everything from scratch and > pack into VB. > > > Actually the destroy seems to work OK. It is when I try > to recreate > > > all the widgets that I get the core dump. > > > > > > I tried having each class destructor first delete it's children > > > (with a 'delete'), then destroy it's own widget (in the > case of the > > > GnomeCanvasItems, using GTK_OBJECT_DESTROY and casting the > > > CanvasItem). I thought this made the most sense since you want to > > > delete the children first before you delete the parent or you'll > > > have children pointing to parents that no longer exist. I also > > > tried reversing the order as well but get the same result. I get > > > error messages like this: > > > > > > GLib-GObject-WARNING **: invalid uninstantiatable type > `gint64' in > > > cast to `GtkObject' > > > > > > Gtk-CRITICAL **: file gtkobject.c: line 358 > > > (gtk_object_destroy): assertion `GTK_IS_OBJECT (object)' failed > > > > > > GLib-GObject-WARNING **: invalid cast from `(null)' to `GtkObject' > > > > > > Gtk-CRITICAL **: file gtkobject.c: line 358 > > > (gtk_object_destroy): assertion `GTK_IS_OBJECT (object)' failed > > > > > > > > > I tried just doing a destroy on HB but get the same results. It > > > seems like I'm leaving something behind. It works a few > times, then > > > crashes. Or it crashes on the first try. > > > > > > Thanks for any help > > > Jason > > > > > > > > > --__--__-- > > > > > > _______________________________________________ > > > > > > gtk-list@xxxxxxxxx http://mail.gnome.org/mailman/listinfo/gtk-list > > > > > > > > > End of gtk-list Digest > _______________________________________________ > > gtk-list@xxxxxxxxx http://mail.gnome.org/mailman/listinfo/gtk-list > _______________________________________________ gtk-list@xxxxxxxxx http://mail.gnome.org/mailman/listinfo/gtk-list
