+ sigc::signal<int, int, unsigned, unsigned> signal_button_press;
+ sigc::signal<int, int, unsigned, unsigned> signal_button_release;
+ sigc::signal<int, int> signal_pointer_motion;
+ sigc::signal<unsigned, unsigned, wchar_t> signal_key_press;
+ sigc::signal<unsigned, unsigned> signal_key_release;
+