How to define function argument as an other function argument

November 10, 2024

For example how to impalement Wrapper::call_to_func
that argument list call_to_func should be as func

class A
{
    void func(int, char, double);
};

template<class T>
class Wrapper
{
public:
    void call_to_func(....)
    {
          m_t.func(....)
    }

    T m_t;
}

>Solution :

You can make call_to_func a variadic method template with a template parameter pack , and use std::forward to perfectly forward the arguments to func:

#include <iostream>
#include <utility>

class A {
public:
    void func(int i, char c, double d) {
        std::cout << "func" << " " << i << " " << c << " " << d << "\n";
    }
};

template<class T>
class Wrapper {
public:
    template <typename ... Ts>
    void call_to_func(Ts&& ... args) {
        m_t.func(std::forward<Ts>(args)...);
    }

    T m_t;
};

int main() { 
    Wrapper<A> w;
    w.call_to_func(1, 'a', 2.3);
}

Output: