Detect if a type is a std::tuple?

Question

Currently I have two functions :

template bool f(Type* x);
template bool f(std::tuple* x);
         


        

Answer 1

With C++17, here is a fairly simple solution using if constexpr

template  struct is_tuple: std::false_type {};

template  struct is_tuple>: std::true_type {};

Then you can do something like:

template bool f(Type* x) {
    if constexpr (is_tuple::value) {
        std::cout << "A tuple!!\n";
        return true;
    }

    std::cout << "Not a tuple\n";
    return false;
}

A test to ensure it worked:

f(&some_tuple);
f(&some_object);

Output:

A tuple!!
Not a tuple

---

Solution taken in part from an answer found here: How to know if a type is a specialization of std::vector?