#include <functional>

using namespace std;

template<typename T>
struct memfun_type
{
    using type = void;
};

template<typename Ret, typename Class, typename... Args>
struct memfun_type<Ret(Class::*)(Args...) const>
{
    using type = std::function<Ret(Args...)>;
};

template<typename F>
typename memfun_type<decltype(&F::operator())>::type
FFL(F const &func)
{ // Function from lambda !
    return func;
}

template <typename... Args> void Callback(std::function<void(Args...)> f){
    // store f and call later
}

int main()
{
    Callback(FFL([](int a, float b){
        // do something
    }));

    return 0;
}