std::chrono:: time_point

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Date and time utilities

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_am is_pm

(C++20) (C++20)

make12 make24

(C++20) (C++20)

hh_mm_ss (C++20)

Calendar

day (C++20)
month (C++20)
year (C++20)
weekday (C++20)
operator/ (C++20)
year_month_day (C++20)

year_month_day_last (C++20)
year_month_weekday (C++20)
year_month_weekday_last (C++20)
weekday_indexed (C++20)
weekday_last (C++20)
month_day (C++20)

month_day_last (C++20)
month_weekday (C++20)
month_weekday_last (C++20)
year_month (C++20)
last_spec last (C++20) (C++20)

Time zone

tzdb (C++20)
tzdb_list (C++20)
get_tzdb get_tzdb_list reload_tzdb remote_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)


                chrono

I/O

parse

(C++20)

C-style date and time

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 Clock or be std::chrono::local_t (since C++20) .

(until C++23)

Member types

Member type	Definition
`clock`	`Clock` , the clock on which this time point is measured
`duration`	`Duration` , a std::chrono::duration type used to measure the time since epoch
`rep`	`Rep` , an arithmetic type representing the number of ticks of the duration
`period`	`Period` , a std::ratio type representing the tick period of the duration

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()
{
    static int 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()
{
    using namespace 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();
 
    const std::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();
 
    const auto 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.

Compiler support
Freestanding and hosted
Language
Standard library
Standard library headers
Named requirements
Feature test macros (C++20)
Language support library
Concepts library (C++20)
Metaprogramming library (C++11)
Diagnostics library
General utilities library
Strings library
Containers library
Iterators library
Ranges library (C++20)
Algorithms library
Numerics library
Localizations library
Input/output library
Filesystem library (C++17)
Regular expressions library (C++11)
Concurrency support library (C++11)
Execution support library (C++26)
Technical specifications
Symbols index
External libraries

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)

std::chrono:: time_point

Member types

Member functions

Non-member functions

Helper classes

Example

See also

Navigation

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