5 Quantities and units library [quantities]
export module mp_units.systems;
export import mp_units.core;
import std;
export namespace mp_units {
template<typename Rep, typename Period>
struct quantity_like_traits<std::chrono::duration<Rep, Period>>;
template<typename Clock>
struct chrono_point_origin_;
template<typename Clock>
constexpr chrono_point_origin_<Clock> chrono_point_origin{};
template<typename Clock, typename Rep, typename Period>
struct quantity_point_like_traits<
std::chrono::time_point<Clock, std::chrono::duration<Rep, Period>>>;
}