std::chrono::system_clock
Defined in header <chrono> | ||
|---|---|---|
class system_clock; | (since C++11) |
Class std::chrono::system_clock represents the system-wide real time wall clock.
It may not be monotonic: on most systems, the system time can be adjusted at any moment. It is the only C++ clock that has the ability to map its time points to C-style time, and, therefore, to be displayed (until C++20).
std::chrono::system_clock meets the requirements of TrivialClock.
| The epoch of | (until C++20) |
|
| (since C++20) |
Time point family
Defined in namespace std::chrono
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template<class Duration> using sys_time = std::chrono::time_point<std::chrono::system_clock, Duration>; | (since C++20) | |
using sys_seconds = sys_time<std::chrono::seconds>; | (since C++20) | |
using sys_days = sys_time<std::chrono::days>; | (since C++20) |
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(C++20) | performs stream output on a sys_time (function template) |
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(C++20) | parses a sys_time from a stream according to the provided format (function template) |
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(C++20) | outputs a sys_time into a stream according to the provided format (function template) |
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::system_clock> |
Member constants
| constexpr bool is_steady
[static] | true if the time between ticks is always constant, i.e. calls to now() return values that increase monotonically even in case of some external clock adjustment, otherwise false (public static member constant) |
Member functions
|
[static] | returns a std::chrono::time_point representing the current point in time (public static member function) |
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[static] | converts a system clock time point to std::time_t (public static member function) |
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[static] | converts std::time_t to a system clock time point (public static member function) |
See also
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(C++11) | monotonic clock that will never be adjusted (class) |
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(C++11) | the clock with the shortest tick period available (class) |
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