std::chrono::time_point<Clock,Duration>:: time_since_epoch

From cppreference.net

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)
`chrono` I/O
parse (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)
C-style date and time

duration time_since_epoch ( ) const ;		(depuis C++11) (constexpr depuis C++14)

Retourne une duration représentant le temps écoulé entre * this et l'époque de l' clock .

Paramètres

(aucun)

Valeur de retour

La durée entre ce time_point et l'époque de l' clock .

Exemple

Exécuter ce code

#include <chrono>
#include <ctime>
#include <iostream>
int main()
{
    const auto p0 = std::chrono::time_point<std::chrono::system_clock>{};
    const auto p1 = std::chrono::system_clock::now();
    const auto p2 = p1 - std::chrono::hours(24);
    std::time_t epoch_time = std::chrono::system_clock::to_time_t(p0);
    std::cout << "epoch: " << std::ctime(&epoch_time);
    std::time_t today_time = std::chrono::system_clock::to_time_t(p1);
    std::cout << "today: " << std::ctime(&today_time);
    std::cout << "hours since epoch: "
              << std::chrono::duration_cast<std::chrono::hours>(
                     p1.time_since_epoch()).count() 
              << '\n';
    std::cout << "yesterday, hours since epoch: "
              << std::chrono::duration_cast<std::chrono::hours>(
                     p2.time_since_epoch()).count() 
              << '\n';
}

Sortie possible :

epoch: Thu Jan  1 00:00:00 1970
today: Fri Jun 30 10:44:11 2017
hours since epoch: 416338
yesterday, hours since epoch: 416314

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)
Diagnostics library
Memory management library
Metaprogramming library (C++11)
General utilities library
Containers library
Iterators library
Ranges library (C++20)
Algorithms library
Strings library
Text processing library
Numerics library
Date and time library
Input/output library
Filesystem library (C++17)
Concurrency support library (C++11)
Execution control 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)

cppreference.net

Namespaces

Variants

std::chrono::time_point<Clock,Duration>:: time_since_epoch

Paramètres

Valeur de retour

Exemple