std::chrono::time_point

 

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Date and time library

Time point time_point (C++11) clock_time_conversion (C++20)   clock_cast (C++20) Duration duration (C++11) Clocks system_clock (C++11) steady_clock (C++11) is_clock (C++20) utc_clock (C++20) tai_clock (C++20) high_resolution_clock (C++11) gps_clock (C++20) file_clock (C++20) local_t (C++20) Time of day is_amis_pm (C++20)(C++20) make12make24 (C++20)(C++20) hh_mm_ss (C++20)

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Time zone tzdb (C++20) tzdb_list (C++20) get_tzdbget_tzdb_listreload_tzdbremote_version (C++20)(C++20)(C++20)(C++20) sys_info (C++20) local_info (C++20) nonexistent_local_time (C++20) ambiguous_local_time (C++20) locate_zone (C++20) current_zone (C++20) time_zone (C++20) choose (C++20) zoned_traits (C++20) zoned_time (C++20) time_zone_link (C++20) leap_second (C++20) leap_second_info (C++20) get_leap_second_info (C++20) C-style date and time

 

std::chrono::time_point

Member functions

time_point::time_point

time_point::time_since_epoch

time_point::operator+=time_point::operator-=

time_point::operator++time_point::operator-- (C++20)(C++20)

time_point::min

time_point::max

Non-member functions

operator+operator-

operator==operator!=operator<operator<=operator>operator>=operator<=> (until C++20)(C++20)

time_point_cast

floor (C++17)

ceil (C++17)

round (C++17)

Helper classes

common_type

hash<std::chrono::time_point> (C++26)

 

Defined in header <chrono>
template<     class Clock,     class Duration =typename Clock::duration >class time_point;		(since C++11)

Class template std::chrono::time_point represents a point in time. It is implemented as if it stores a value of type Duration indicating the time interval from the start of the Clock's epoch.

Clock must meet the requirements for Clockor be std::chrono::local_t(since C++20).

(until C++23)

Member types

Type	Description
Clockclock	the clock on which this time point is measured (typedef)
Durationduration	a std::chrono::duration type used to measure the time since epoch (typedef)
duration::reprep	an arithmetic type representing the number of ticks of the duration (typedef)
duration::periodperiod	a std::ratio type representing the tick period of the duration (typedef)

Member functions

(constructor)	constructs a new time point (public member function)
time_since_epoch	returns the time point as duration since the start of its clock (public member function)
operator+=operator-=	modifies the time point by the given duration (public member function)
operator++operator++(int)operator--operator--(int) (C++20)	increments or decrements the duration (public member function)
min [static]	returns the time point corresponding to the smallest duration (public static member function)
max [static]	returns the time point corresponding to the largest duration (public static member function)

Non-member functions

operator+operator- (C++11)	performs add and subtract operations involving a time point (function template)
operator==operator!=operator<operator<=operator>operator>=operator<=> (C++11)(C++11)(removed in C++20)(C++11)(C++11)(C++11)(C++11)(C++20)	compares two time points (function template)
time_point_cast (C++11)	converts a time point to another time point on the same clock, with a different duration (function template)
floor(std::chrono::time_point) (C++17)	converts a time_point to another, rounding down (function template)
ceil(std::chrono::time_point) (C++17)	converts a time_point to another, rounding up (function template)
round(std::chrono::time_point) (C++17)	converts a time_point to another, rounding to nearest, ties to even (function template)

Helper classes

std::common_type<std::chrono::time_point> (C++11)	specializes the std::common_type trait (class template specialization)
std::hash<std::chrono::time_point> (C++26)	hash support for std::chrono::time_point (class template specialization)

Example

Run this code

#include <algorithm>#include <chrono>#include <ctime>#include <iomanip>#include <iostream>   void slow_motion(){staticint a[]{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12};// Generate Γ(13) == 12! permutations:while(std::ranges::next_permutation(a).found){}}   int main(){usingnamespace std::literals;// enables literal suffixes, e.g. 24h, 1ms, 1s.   const std::chrono::time_point<std::chrono::system_clock> now =std::chrono::system_clock::now();   conststd::time_t t_c =std::chrono::system_clock::to_time_t(now - 24h);std::cout<<"24 hours ago, the time was "<<std::put_time(std::localtime(&t_c), "%F %T.\n")<<std::flush;   const std::chrono::time_point<std::chrono::steady_clock> start =std::chrono::steady_clock::now();   std::cout<<"Different clocks are not comparable: \n"" System time: "<< now.time_since_epoch()<<"\n"" Steady time: "<< start.time_since_epoch()<<'\n';   slow_motion();   constauto end =std::chrono::steady_clock::now();std::cout<<"Slow calculations took "<<std::chrono::duration_cast<std::chrono::microseconds>(end - start)<<" ≈ "<<(end - start)/ 1ms <<"ms ≈ "// almost equivalent form of the above, but<<(end - start)/ 1s <<"s.\n";// using milliseconds and seconds accordingly}

Possible output:

24 hours ago, the time was 2021-02-15 18:28:52. Different clocks are not comparable: System time: 1666497022681282572ns Steady time: 413668317434475ns Slow calculations took 2090448µs ≈ 2090ms ≈ 2s.

See also

duration (C++11)	a time interval (class template)
year_month_day (C++20)	represents a specific year, month, and day (class)