class EventServer
{
public:
	EventServer();
	virtual ~EventServer();
	virtual void RegisterListener(EventListener *l);
	virtual void SendEvent(SDL_Event *e);
private:
	std::vector<EventListener *> listeners;

};

EventServer::EventServer() {
	listeners.reserve(4);
}

causes error
c:\haloweencontest\haloweencontest\eventpump.cpp(3) : error C2533: 'EventPump::{ctor}' : constructors not allowed a return type