duration time_since_epoch() const;
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(C++11 起) (C++14 前) |
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constexpr duration time_since_epoch() const;
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(C++14 起) | |
返回表示 *this 与 clock
的纪元间的时间量的 duration 。
(无)
此 time_point
与 clock
的纪元间的时间量
#include <iostream> #include <chrono> #include <ctime> int main() { std::chrono::time_point<std::chrono::system_clock> p1, p2, p3; p2 = std::chrono::system_clock::now(); p3 = p2 - std::chrono::hours(24); std::time_t epoch_time = std::chrono::system_clock::to_time_t(p1); std::cout << "epoch: " << std::ctime(&epoch_time); std::time_t today_time = std::chrono::system_clock::to_time_t(p2); std::cout << "today: " << std::ctime(&today_time); std::cout << "hours since epoch: " << std::chrono::duration_cast<std::chrono::hours>( p2.time_since_epoch()).count() << '\n'; std::cout << "yesterday, hours since epoch: " << std::chrono::duration_cast<std::chrono::hours>( p3.time_since_epoch()).count() << '\n'; }
可能的输出:
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