Re: wy signal handler could not be override

[Jonas Platte <jonasplatte myopera com>]

Am 29.03.2013 12:52, schrieb Klaus Rudolph:
> I want to override a signal handler in a derived class:
>   
> class MyRect : public Goocanvas::Rect
> {
>      public:
>          MyRect( double x, double y, double w, double h):
>              Goocanvas::Rect( x,y,w,h)
>      {
>      }
>
>      public:
>          bool on_button_press_event(const Glib::RefPtr<Item>& target, GdkEventButton* event)
>          {
>              cout << "catch it" << endl;
>              return true;
>          }
> };
>
> But the handler is never invoked!
>
> Any advice how to override a signal handler?
>
> Manual adding the handler by
>
> (Glib::RefPtr<Goocanvas::Item>&)m_rect_own)->signal_button_press_event().connect(sigc::ptr_fun(&MyHandler4));
>
> works. But this is not very handy :-(
>
> Regards
>   Klaus
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I've googled the thing and can't find any mistake in your function.
But to make sure you're really overriding the function, you can use the 
override keyword from C++11, if your compiler supports that. For g++, 
you can activate C++11 features with the -std=c++11 compiler flag (I'm 
not sure if that is necessary)

You would then declare the function as follows:

virtual bool on_button_press_event(const Glib::RefPtr<Item>& target, GdkEventButton* event) override
{
        cout << "catch it" << endl;
        return true;
}