Re: [gtkmm] Slots from non-Gtk subclasses.

[MHL Schulze t-online de (Martin Schulze)]

Am 2003.02.24 07:25 schrieb(en) Andrew E. Makeev:
> > > > > I have a class that isn't derived from any Gtk classes.  It does,
> > > > > however, have member functions that will pop up Gtk windows, and
> > > > > member functions that will handle callbacks from those windows.
> > > > >
> > > > > The problem is that the "SigC::slot(class, &member)" function seems
> > > > > to require a class who's derived from Gtk.  I can't get the class to
> > > > > compile unless I force my class to be a subclass of a Gtk class.
> > > > class Foo : public SigC::Object { ... }
> > > Actually,
> > >
> > > class Foo : virtual public SigC::Object { ... };
> Why this solution was not mentioned yet?
> There is a way to connect method of a class that is not derived from 
> SigC::Object.
> I've read something about "use it on your own risk" earlier, but haven't met 
> any problem with it for now.
>
>
> #include <sigc++/class_slot.h>
>
> ...
>
> <SIGNAL>.connect (SigC::slot_class(<MyClass>, &<MyFunc>));
>
> ...

You will experience problems if the lifetime of the <SIGNAL> object
exceeds the lifetime of the <MyClass> object: The connection won't
be destroyed automatically and unless you destroy the connection
manually your program segfaults on <SIGNAL>.emit()!

By the way: According to my rusty c++ knowledge you should only
use virtual base classes if you really need them for efficiency reasons.

Regards,

  Martin