std::chrono::time_point_cast
来自cppreference.com
< cpp | chrono | time point
| template <class ToDuration, class Clock, class Duration> time_point<Clock, ToDuration> time_point_cast( |
(C++11 起) (C++14 前) |
|
| template <class ToDuration, class Clock, class Duration> constexpr time_point<Clock, ToDuration> time_point_cast( |
(C++14 起) | |
将 std::chrono::time_point 从一个 duration 到另一个。
示例
| t | - | 转换来源的 time_point
|
返回值
std::chrono::time_point<Clock, ToDuration>(std::chrono::duration_cast<ToDuration>(t.time_since_epoch()))
注意
仅若 ToDuration 为 duration 的实例， time_point_cast 才会参与重载决议。
示例
运行此代码
#include <iostream> #include <chrono> using Clock = std::chrono::high_resolution_clock; using Ms = std::chrono::milliseconds; using Sec = std::chrono::seconds; template<class Duration> using TimePoint = std::chrono::time_point<Clock, Duration>; inline void print_ms(const TimePoint<Ms>& time_point) { std::cout << time_point.time_since_epoch().count() << " ms\n"; } int main() { TimePoint<Sec> time_point_sec(Sec(4)); // 隐式转换，无精度损失 TimePoint<Ms> time_point_ms(time_point_sec); print_ms(time_point_ms); // 4000 ms time_point_ms = TimePoint<Ms>(Ms(5756)); // 显式转型，在精度损失可能发生时需要 // 5756 truncated to 5000 time_point_sec = std::chrono::time_point_cast<Sec>(time_point_ms); print_ms(time_point_sec); // 5000 ms }
输出：
4000 ms 5000 ms
