Clock

The clock consists of a starting point and a tick. So you can get the current time with the method now.

• std::chrono::system_clock:
  System time, which you can synchronize with the external clock.

• std::chrono::steady_clock:
  Clock, which can not be adjusted.

• std::chrono::high_resolution_clock:
  System time with the greatest accuracy.

std::chrono::system_clock will refer typically to the 1.1.1970. You can not adjust std::steady_clock forward or backward in opposite to two other clocks. The methods to_time_t and from_time_t can be used to convert between std::chrono::system_clock and std::time_t objects.