On Mon, 2008-03-17 at 10:16 +0100, Gabriele Greco wrote:
[snip]
> Actually I cover only the widgets I use in this app. I'm not using gtkmm
> mostly to avoid extra dependencies.
>
> Anyway let's talk about the problem.
>
> Gtk owns all toplevel windows. It already does _ref_sink() on
> > GtkWindows on creation (see gtk_window_init() in gtk/gtkwindow.c). In
> > this case, if you want to keep an extra reference to 'w', you'd just
> > call g_object_ref() on it.
>
>
> Ok, the problem is that I expected to be able to delete those top level
> windows with g_object_unref(), but it seems it's not enough, here is an
> example:
>
> int main()
> {
> gtk_init(NULL, NULL);
>
> GtkWidget *w = gtk_window_new(GTK_WINDOW_TOPLEVEL);
>
> gtk_widget_show(w);
>
> GtkWidget *d = gtk_message_dialog_new(NULL,
> GTK_DIALOG_MODAL,
> GTK_MESSAGE_INFO,
> GTK_BUTTONS_CLOSE,
> "Hello!");
> gtk_dialog_run(GTK_DIALOG(d));
> fprintf(stderr, "After run!\n");
> g_object_unref(d);
> fprintf(stderr, "After unref\n");
>
> gtk_main();
> }
>
> The message dialog is still opened after the unref, if I want to get rid of
> it I have to use gtk_widget_destroy() that is not what I want cause I may
> not be the owner of the object.
>
> This should be ok as well, IFF you've previously called g_object_ref()
> > and thus own a reference to it. As I said, Gtk owns the initial
> > (non-floating) reference GtkWindow that you get back with
> > gtk_window_new().
>
>
> Adding an additional reference to the dialog don't help me close it with
> g_object_unref()...
>
> This more or less works (because non-window GtkObjects are created
> > floating), but that's usually not what you'd want to do. Again you'd
> > probably want to just take a normal reference on the widget and then
> > unref it when you don't need it anymore. When you add a widget to a
> > container, it will take care of ditching the floating reference and
> > taking a real reference.
>
>
> This is what I want and it works perfectly except for top level windows :)
> With toplevel windows I'm unable to get rid of them with the same method I
> use with the other objects (g_object_unref), I can superclass it to do
> gtk_widget_destroy() if I see that the object count is 2 or less (since my
> reference is added to the initial one of GTK), but I'd like a cleaner way.
You cannot get rid of a top level window using g_object_unref() because
a reference is owned by GTK+. It is not that it is "not enough", it is
that it is generally not the way to do it - you cannot generally get rid
of a widget that way, because other containers may own references. It
is only really for use where you have yourself called g_object_ref() or
g_object_ref_sink() on it for your own purposes.
There is an explanation of this at:
http://library.gnome.org/devel/gtk/stable/GtkObject.html
If you want some light-weight lifetime wrappers for using GTK+ in a
program written in C++, this might give you some ideas, but gtkmm is
also a good choice:
http://efax-gtk.cvs.sourceforge.net/*checkout*/efax-gtk/efax-gtk/src/utils/gobj_handle.h
http://efax-gtk.cvs.sourceforge.net/*checkout*/efax-gtk/efax-gtk/src/utils/window.h
http://efax-gtk.cvs.sourceforge.net/*checkout*/efax-gtk/efax-gtk/src/utils/window.cpp
http://efax-gtk.cvs.sourceforge.net/*checkout*/efax-gtk/efax-gtk/src/utils/widget.h
http://efax-gtk.cvs.sourceforge.net/*checkout*/efax-gtk/efax-gtk/src/utils/widget.cpp
Chris
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