20 General utilities library [utilities]

20.12 Time utilities [time]

20.12.7 Clocks [time.clock]

20.12.7.3 Class high_resolution_clock [time.clock.hires]

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:
  typedef unspecified                               rep;
  typedef ratio<unspecified, unspecified>          period;
  typedef chrono::duration<rep, period>              duration;
  typedef chrono::time_point<unspecified, duration> time_point;
  static constexpr bool is_steady =               unspecified;

  static time_point now() noexcept;
};