Re: glist manipulation and reference count
On Fri, 2009-05-15 at 19:42 +0200, Sven Neumann wrote: > Hi, > > On Thu, 2009-05-14 at 20:47 -0700, walty wrote: > > > However, one thing that surprised me is that, when I do "g_list_append" or > > "g_list_prepend", it does not automatically add the reference count of the > > stored GObject (unlike objective-C). > > It would be nice to have some container implementations in GObject that > deal with reference counting automatically. We recently got that for GPtrArray (insofar you can pass g_object_unref to g_ptr_array_set_free_func()), see http://bugzilla.gnome.org/show_bug.cgi?id=580450 which is in GLib 2.21 already. The other half of this work is http://bugzilla.gnome.org/show_bug.cgi?id=581106 which I'm hoping to get committed as well. > The classes found in libgee > http://live.gnome.org/Libgee could serve as a starting point. There's been a couple of very heated discussions about this on this list and in bug 560061. It seems like the GLib maintainers don't want things like this. David ___ gtk-devel-list mailing list gtk-devel-list@gnome.org http://mail.gnome.org/mailman/listinfo/gtk-devel-list
Re: glist manipulation and reference count
Hi, On Thu, 2009-05-14 at 20:47 -0700, walty wrote: > However, one thing that surprised me is that, when I do "g_list_append" or > "g_list_prepend", it does not automatically add the reference count of the > stored GObject (unlike objective-C). It would be nice to have some container implementations in GObject that deal with reference counting automatically. The classes found in libgee http://live.gnome.org/Libgee could serve as a starting point. Sven ___ gtk-devel-list mailing list gtk-devel-list@gnome.org http://mail.gnome.org/mailman/listinfo/gtk-devel-list
Re: glist manipulation and reference count
> I think I had some confusion here, I thought GObject is part of GLib, and > apparently that's not true. You are confusing GLib and libglib. The "GLib" software consists of five (shared) libraries: libglib, libgmodule, libgthread, libgobject and libgio. Sure, with hindsight, it perhaps would have made sense to combine the functionality of the first three into one, or even more, but that can't be changed now. The GObject API is in libgobject, so it is part of GLib, but not of libglib. Hope this helps. --tml ___ gtk-devel-list mailing list gtk-devel-list@gnome.org http://mail.gnome.org/mailman/listinfo/gtk-devel-list
Re: glist manipulation and reference count
Hi Brian, Thanks for the reply. I think I had some confusion here, I thought GObject is part of GLib, and apparently that's not true. The scenario is that I need to temporary update the screen, and store the old widgets on the list. So if I did not explicitly add the ref count, the objects would be destroyed once they are removed from parent (even if I stored the object reference in g_list). I think I would use a general helper function for list insert & remove then. Just want to make sure I did not miss something obvious. And I would move my future questions to gtk-app-devel-list :P Thanks again. walty Brian J. Tarricone wrote: > > [Note that your question is probably more appropriate for > gtk-app-devel-list or gtk-list; this list is for the development *of* > glib/gtk itself, not about developing apps that *use* glib/gtk.] > > On 05/14/2009 08:47 PM, walty wrote: > >> However, one thing that surprised me is that, when I do "g_list_append" >> or >> "g_list_prepend", it does not automatically add the reference count of >> the >> stored GObject (unlike objective-C). > > GList is a generic container that you can put any kind of pointer into. > It doesn't know about GObjects or reference counting. In fact libglib > (where GList is implemented) doesn't even link to libgobject. > >> So do I need to explicitly add the reference count each time the GObject >> is >> inserted? and reduce the reference count when the object is removed? That >> seems quite cumbersome to me. > > That depends on how you want to use it. If you can be sure no one else > will destroy the object while you're using it in the list, then no, you > don't. > > I've used both glib/gobject and NSArray/NSDictionary/etc., and > personally I don't find either approach to be better or worse. I rarely > need to increase refcnts on GObjects when I store them in lists, but > perhaps others have different use cases that do require this. > >> Or can I add some function pointer to generalize this? Is there some kind >> of >> best practice on this? > > If you add the objects in one shot, you can do something like this after > you've added all objects: > > g_list_foreach(list, (GFunc)g_object_ref, NULL); > > Of course that iterates over the entire list, so it would be a bit slow > on a large list. You can always ref the objects as you insert them, e.g.: > > list = g_list_append(list, g_object_ref(obj)); > > Of course you have to do something similar with _unref() when you remove > items from the list or destroy the list. > > -brian > ___ > gtk-devel-list mailing list > gtk-devel-list@gnome.org > http://mail.gnome.org/mailman/listinfo/gtk-devel-list > > -- View this message in context: http://www.nabble.com/glist-manipulation-and-reference-count-tp23552925p23553156.html Sent from the Gtk+ - Dev - General mailing list archive at Nabble.com. ___ gtk-devel-list mailing list gtk-devel-list@gnome.org http://mail.gnome.org/mailman/listinfo/gtk-devel-list
Re: glist manipulation and reference count
[Note that your question is probably more appropriate for gtk-app-devel-list or gtk-list; this list is for the development *of* glib/gtk itself, not about developing apps that *use* glib/gtk.] On 05/14/2009 08:47 PM, walty wrote: However, one thing that surprised me is that, when I do "g_list_append" or "g_list_prepend", it does not automatically add the reference count of the stored GObject (unlike objective-C). GList is a generic container that you can put any kind of pointer into. It doesn't know about GObjects or reference counting. In fact libglib (where GList is implemented) doesn't even link to libgobject. So do I need to explicitly add the reference count each time the GObject is inserted? and reduce the reference count when the object is removed? That seems quite cumbersome to me. That depends on how you want to use it. If you can be sure no one else will destroy the object while you're using it in the list, then no, you don't. I've used both glib/gobject and NSArray/NSDictionary/etc., and personally I don't find either approach to be better or worse. I rarely need to increase refcnts on GObjects when I store them in lists, but perhaps others have different use cases that do require this. Or can I add some function pointer to generalize this? Is there some kind of best practice on this? If you add the objects in one shot, you can do something like this after you've added all objects: g_list_foreach(list, (GFunc)g_object_ref, NULL); Of course that iterates over the entire list, so it would be a bit slow on a large list. You can always ref the objects as you insert them, e.g.: list = g_list_append(list, g_object_ref(obj)); Of course you have to do something similar with _unref() when you remove items from the list or destroy the list. -brian ___ gtk-devel-list mailing list gtk-devel-list@gnome.org http://mail.gnome.org/mailman/listinfo/gtk-devel-list
