Re: [sigc] conditions in libsigc

[Murray Cumming <murrayc murrayc com>]

On Thu, 2006-07-06 at 21:55 +0100, Chris Vine wrote:
> On Thursday 06 July 2006 21:44, Chris Vine wrote:
> >
> > Glib::RefPtr is designed to reference objects derived from GObject (sorry,
> > I can't remember their glibmm class designation, probably Glib::Object) but
> > not from GtkObject (Gtk::Object).  Classes derived from Gtk::Object are
> > owned by the container in which they are placed, if you provide they are to
> > be managed (as you did).  If you assign them to a Glib::RefPtr you will
> > need to increment the reference count when doing so in order to pass
> > ownership to the Glib::RefPtr smart pointer.  If you don't have them as
> > managed objects, you don't need to increment the reference count (but you
> > may have to call gtk_object_sink() on them to eliminate the floating
> > reference - I am not sure whether you need to do this in gtkmm because I
> > either use the raw C objects or, with gtkmm, have them managed by the
> > container).
> 
> Actually I am not sure if I am right about the last sentence - it is true with 
> GTK+ (with C objects) but I am not sure about gtkmm - you probably need to 
> call delete on the gtkmm object at some stage if it is not managed by the 
> container, since bringing the reference count to 0 will cause the underlying 
> C object to be destroyed but not the C++ superstructure on top.  The best 
> rule is never to use Glib::RefPtr with objects derived from Gtk::Object.

Your conclusion is correct.
http://www.gtkmm.org/gtkmm2/docs/tutorial/html/ch18.html

-- 
Murray Cumming
murrayc murrayc com
www.murrayc.com
www.openismus.com