Clocks

The fact that there are three different types of clocks begs the question: What are the differences?

• std::chrono::sytem_clock: is the system-wide real-time clock (wall-clock). The clock has the auxiliary functions to_time_t and from_time_t to convert time points into calendar time.
• std::chrono::steady_clock: is the only clock to provide the guarantee that you can not adjust it. Therefore, std::chrono::steady_clock is the preferred clock to measure time intervals.
• std::chrono::high_resolution_clock: is the clock with the highest accuracy but it can be simply an alias for the clocks std::chrono::system_clock or std::chrono::steady_clock.

No guarantees about the accuracy, starting point, and valid time range

The C++ standard provides no guarantee about the accuracy, the starting point or the valid time range of the clocks. Typically, the starting point of std::chrono:system_clock is the 1.1.1970, the so-called UNIX-epoch, while for std::chrono::steady_clock it...