Objects of class high_resolution_clock represent clocks with the shortest tick period. high_resolution_clock may be a synonym for system_clock or steady_clock.
class high_resolution_clock { public: using rep = unspecified; using period = ratio<unspecified, unspecified>; using duration = chrono::duration<rep, period>; using time_point = chrono::time_point<unspecified, duration>; static constexpr bool is_steady = unspecified; static time_point now() noexcept; };