std::chrono::utc_clock(3)

NAME
std::chrono::utc_clock - std::chrono::utc_clock

Synopsis
   Defined in header <chrono>
   class utc_clock; (since C++20)
   The clock std::chrono::utc_clock is a Clock that represents Coordinated Universal
   Time (UTC). It measures time since 00:00:00 UTC, Thursday, 1 January 1970, including
   leap seconds.
   utc_clock meets the Clock requirements. It does not meet the TrivialClock
   requirements unless the implementation can guarantee that now() does not throw an
   exception.

Member types
   Member type Definition
   rep signed arithmetic type representing the number of ticks in the clock's
               duration
   period a std::ratio type representing the tick period of the clock, in seconds
   duration std::chrono::duration<rep, period>, capable of representing negative
               durations
   time_point std::chrono::time_point<std::chrono::utc_clock>

Member constants
                        true if the time between ticks is always constant, i.e.
   constexpr bool is_steady calls to now() return values that increase monotonically
   [static] even in case of some external clock adjustment, otherwise
                        false
                        (public static member constant)

Member functions
   now returns a std::chrono::time_point representing the current point in time
   [static] (public static member function)
   to_sys converts utc_time to sys_time
   [static] (public static member function)
   from_sys converts sys_time to utc_time
   [static] (public static member function)

Non-member functions
   get_leap_second_info obtains leap second insertion information from a utc_time
   (C++20) object
                        (function template)

Helper classes
   leap_second_info leap second insertion information
   (C++20) (class)

Notes
   The official UTC epoch is 1 January 1972. utc_clock uses 1 January 1970 instead to
   be consistent with std::chrono::system_clock.