Re: Faling to wrap object in signal handler

[Kjell Ahlstedt <kjell ahlstedt bredband net>]

2012-03-04 18:45, A J Delaney brighton ac uk skrev:
> Dear all,
> 	I've been extending the clutter-box2dmm bindings and have run into
> another issue.  I have exposed the signal_collision so that you can now
> tell if two Box2DChild objects have collided.  It is also necessary to
> expose Box2DCollision, which I have done.
>
> I can now connect up the callback on a child
> b2dchild->signal_collision().connect(sigc::ptr_fun(&handle_collision));
>
> To call a function such as,
> static void
> handle_collision(const Glib::RefPtr<Clutter::Box2D::Box2DCollision>&  c)
> { ... }
>
> In the mainline I can create() objects of type
> Glib::RefPtr<Clutter::Box2D::Box2DCollision>.  However, any time I enter
> the signal handler I get a
> "glibmm-WARNING **: Failed to wrap object of type
> 'ClutterBox2DCollision'. Hint: this error is commonly caused by failing
> to call a library init() function."
>
> and the signal handler is defined (by gmmproc) as
> Glib::SignalProxy1<  void,const
> Glib::RefPtr<Clutter::Box2D::Box2DCollision>  &  >
> Box2DChild::signal_collision()
>
> static const Glib::SignalProxyInfo Box2DChild_signal_collision_info =
> {
>    "collision",
>    (GCallback)&Box2DChild_signal_collision_callback,
>    (GCallback)&Box2DChild_signal_collision_callback
> };
>
> There is also a gmmproc provided
> Glib::RefPtr<Clutter::Box2D::Box2DCollision>  wrap(ClutterBox2DCollision*
> object, bool take_copy)
>
> And Box2DChild_signal_collision_callback has signature
> static void Box2DChild_signal_collision_callback(ClutterBox2DChild*
> self, ClutterBox2DCollision* p0,void* data)
>
> Have I forgotten to override some other wrapper method for
> ClutterBox2DCollision * to a RefPtr for Clutter::Box2D::Box2DCollision?
It's possible that the wrap_init() function, generated by 
generate_wrap_init.pl, does not correctly register 
Clutter::Box2D::Box2DCollision_Class::wrap_new(). Possible reasons:

1. generate_wrap_init.pl has not been told to read the .hg file where 
Clutter::Box2D::Box2DCollision is defined.

2. No _GMMPROC_EXTRA_NAMESPACE(Box2D) in the .hg file.
generate_wrap_init.pl ignores namespace declarations. It gets the name 
of the main namespace (Clutter in your case) from a command argument. If 
there are sub-namespaces (Box2D in your case) they must be given in a 
_GMMPROC_EXTRA_NAMESPACE macro that generate_wrap_init.pl does read. See 
the Gio::DBus files, e.g.
http://git.gnome.org/browse/glibmm/tree/gio/src/dbusconnection.hg

3. Both Clutter::Box2D::Box2DCollision and Clutter::Box2DCollision exist 
(or Clutter::xxx::Box2DCollision where xxx is any namespace name other 
than Box2D), and you use a version of generate_wrap_init.pl where bug 
640029 has not been fixed. It was fixed very recently, 2012-02-28 in git.

Kjell