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.

Time point family

Defined in namespace std::chrono
template<class Duration>
using utc_time = std::chrono::time_point<std::chrono::utc_clock, (since C++20)
Duration>;
using utc_seconds = utc_time<std::chrono::seconds>; (since C++20)

operator<<(std::chrono::utc_time) performs stream output on a utc_time
(C++20) (function template)
from_stream(std::chrono::utc_time) parses a utc_time from a stream according to
(C++20) the provided format
(function template)
std::formatter<std::chrono::utc_time> specialization of std::formatter that formats
(C++20) a utc_time according to the provided format
(class template specialization)

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.