Below is the code for my templated callback implementation. Currently it works for a single parameter. One thing I was going to try and do next was increase the argument to the function from 1..N arguments. Ideally this would be as simple as adding Args... everywhere using variadic templates. I don't have a lot of experience yet with variadic templates so any advice on this is helpful.
#include <iostream> #include <vector> template <typename R, typename Arg> class Callback { public: typedef R (*FuncType)(void*, Arg); Callback (FuncType f, void* subscription) : f_(f), subscription_(subscription) { } R operator()(Arg a) { (*f_)(subscription_,a); } private: FuncType f_; void* subscription_; }; template <typename R, typename Arg, typename T, R (T::*Func)(Arg)> R CallbackWrapper (void* o, Arg a) { return (static_cast<T*>(o)->*Func)(a); } class Pricer { public: typedef Callback<void,unsigned int> CbType; void attach ( CbType cb ) { callbacks_.emplace_back(cb); } void receivePrice ( double price ) { broadcast(static_cast<unsigned int>(price*100)); } void broadcast (unsigned int price) { for ( auto& i : callbacks_) { { i(price); } } private: std::vector<CbType> callbacks_; }; class iStrategy { public: Strategy(pricePricer* p); : p_(p) { p->attach(Callback<void,unsigned int>(&CallbackWrapper<void,unsigned int, Strategy, &Strategy::update>, static_cast<void *>(this))); } void }update(unsigned int price) { private: //update model with price std::vector<CbType>cout callbacks_;<< "Received price: " << price / 100.0 << std::endl; } private: Pricer* p_; }; int main ( int argc, char *argv[]) { Pricer p; Strategy s(&p); p.receivePrice(105.67); } 
