问题描述
起初我认为它可以用于性能测量.但说 std::chrono::high_resolution_clock 可能不是稳定(is_steady 可能是 false).也有人说std::chrono::high_resolution_clock 甚至可能是std::chrono::system_clock 的别名，一般不太稳定.所以我不能用这种类型的时钟测量时间间隔，因为随时可能调整时钟，我的测量结果会出错.
At first I thought it can be used for performance measurements. But it is said that std::chrono::high_resolution_clock may be not steady (is_steady may be false). It is also said that std::chrono::high_resolution_clock may even be an alias of std::chrono::system_clock which is generally not steady. So I can't measure time intervals with this type of clock because at any moment the clock may be adjusted and my measurements will be wrong.
同时我无法将 std::chrono::high_resolution_clock 的时间点转换为日历时间，因为它没有 to_time_t 方法.所以我也无法使用这种类型的时钟获得实时.
At the same time I can't convert time points of std::chrono::high_resolution_clock to calendar time because it doesn't have to_time_t method. So I can't get the real time with this type of clock either.
那std::chrono::high_resolution_clock有什么用?
推荐答案
没有.
抱歉，我不好.
如果您想使用high_resolution_clock，请选择steady_clock.在 libc++ 和 VS 上，high_resolution_clock 无论如何都是 steady_clock 的类型别名.
If you are tempted to use high_resolution_clock, choose steady_clock instead. On libc++ and VS high_resolution_clock is a type alias of steady_clock anyway.
在 gcc 上 high_resolution_clock 是 system_clock 的类型别名，我在这个平台上看到了不止一次 high_resolution_clock::to_time_t 的使用(这是错误的).
On gcc high_resolution_clock is a type alias of system_clock and I've seen more than one use of high_resolution_clock::to_time_t on this platform (which is wrong).
做使用<chrono>的某些部分您应该避免.
Do use <chrono>. But there are parts of <chrono> that you should avoid.
- 不要使用
high_resolution_clock. - 避免使用
.count()和.time_since_epoch()除非没有其他方法可以完成工作. - 避免使用
duration_cast，除非代码没有它就无法编译，并且您希望截断到零的行为. - 如果隐式转换编译成功，请避免使用显式转换语法.
- Don't use
high_resolution_clock. - Avoid uses of
.count()and.time_since_epoch()unless there is no other way to get the job done. - Avoid
duration_castunless the code won't compile without it, and you desire truncation-towards-zero behavior. - Avoid explicit conversion syntax if an implicit conversion compiles.
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