std::chrono::time_point<Clock,Duration>::time_since_epoch
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std::chrono::time_point
Member functions
time_point::time_since_epoch
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(until C++20)(C++20)
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(C++26)
duration time_since_epoch() const;
(since C++11) (constexpr since C++14)
Returns a duration representing the amount of time between *this and the clock's epoch.
[edit] Parameters
(none)
[edit] Return value
The amount of time between this time_point and the clock's epoch.
[edit] Example
Run this 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'; }
Possible output:
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