Using Member Type from Template Parameter

Question

I'm interested in doing some thing like this.

template<typename Clock>
struct A {
    Clock::time_point time;
}

A<chrono::steady_clock> a;

However this is not possible. How can I achieve this?

I think there maybe away around using this method in Clock's context but what is the proper way to do this in general?

Answer 1

Since Clock::time_point is a dependent type, you need the typename keyword

template<typename Clock>
struct A {
    typename Clock::time_point time;
};