29 Time library [time]

29.7 Clocks [time.clock]

29.7.7 Class steady_­clock [time.clock.steady]

namespace std::chrono { class steady_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 = true; static time_point now() noexcept; }; }
Objects of class steady_­clock represent clocks for which values of time_­point never decrease as physical time advances and for which values of time_­point advance at a steady rate relative to real time.
That is, the clock may not be adjusted.