CODEWITHSUNDEEP
c++functiontemplatesc++11bind
Gustavo
Gustavo

Reputation: 153

C++ bind member function with variadic template

My example below uses variadic templates to register a function inside a class. Registering a single function works but what about class member functions? I tried std::bind but this expects placeholders which is not an option because I don't know the number of arguments. Is there a simple way doing this in C++11 or am I forced to implement the register function for every amount of arguments?

template<typename TReturn, typename... TArgs>
class Func {
    std::function<TReturn (TArgs...)> fn;

    template<typename TFunction, typename TObject>
    bool register(TFunction f, TObject obj){

    }

    bool register(std::function<TReturn (TArgs...)> f){
        fn = f;
        return true;
    }   
}

Upvotes: 2

Views: 1205

Answers (1)

Pradhan
Pradhan

Reputation: 16737

Create a lambda function with the required signature and construct the std::function object from it. 

template<typename TReturn, typename... TArgs>
class Func {
    std::function<TReturn (TArgs...)> fn;

    template<typename TFunction, typename TObject>
    bool Register(TFunction f, TObject obj){
        fn = [obj](TArgs... args){return (obj.*f)(args...);};
        return true;
    }

    bool Register(std::function<TReturn (TArgs...)> f){
        fn = f;
        return true;
    }   
}

(Note : Member function pointers need to be used with a corresponding object, object reference or a pointer to an object of the appropriate class. If TObject is value-like, the member function call syntax would be (obj.*f). If TObject is pointer-like, the syntax would be (obj->*f).)

Upvotes: 3

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