#include <map>

class Widget {
	public:
		enum Signal {
			NONE
		};
		typedef void(*Callback)(Widget&, Signal);
		typedef std::pair<Widget::Signal, Callback> Event;
		typedef std::multimap<Widget::Signal, Callback> EventTable;

		void insert(Signal signal, Callback callback);

	private:
		EventTable table;
};

void Widget::insert(Widget::Signal signal, Widget::Callback callback) {
	table.insert(signal, callback);
}

void bar(void);

void bar(Widget& w, Widget::Signal s) {
}

int main() {
	Widget w;
	w.insert(Widget::NONE, bar);

	return 0;
}