C++中的时差

问题描述

有谁知道如何在 C++ 中以毫秒为单位计算时间差?我使用了 difftime 但它没有足够的精度我正在尝试测量什么.

Does anyone know how to calculate time difference in C++ in milliseconds? I used difftime but it doesn't have enough precision for what I'm trying to measure.

推荐答案

您必须使用一种更具体的时间结构，timeval(微秒分辨率)或 timespec(纳秒分辨率)，但您可以手动进行相当容易:

You have to use one of the more specific time structures, either timeval (microsecond-resolution) or timespec (nanosecond-resolution), but you can do it manually fairly easily:

#include <time.h>

int diff_ms(timeval t1, timeval t2)
{
    return (((t1.tv_sec - t2.tv_sec) * 1000000) + 
            (t1.tv_usec - t2.tv_usec))/1000;
}

如果时间差异非常大(或者如果您有 16 位整数)，这显然存在整数溢出问题，但这可能不是常见情况.

This obviously has some problems with integer overflow if the difference in times is really large (or if you have 16-bit ints), but that's probably not a common case.

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