How to create a function that receives a function, calls it and returns it on C++?

Question

I'm trying to create a function that receives a function, calls it and returns it back. I've tried several things already, including a lot of template combinations, an none seems to work. What is the correct way to do this?

Answer 1

template <typename Functor>
Functor your_function(Functor toCall)
{
    toCall();
    return toCall;
}

---

If you want to return what the functor returns, then you'd use something like:

// Requires C++11
#include <type_traits>

template <typename Functor>
typename std::result_of<Functor()>::type your_function(Functor toCall)
{
    return toCall();
}

Also note that this will get easier in C++14 with decltype(auto):

//Requires C++14    
template <typename Functor>
decltype(auto) your_function(Functor toCall)
{
    return toCall();
}