Linux和Windows毫秒时间 [英] Linux and Windows millisecond time

问题描述

我想获取系统的毫秒级时间（我不在乎它是否是实时的，我希望它尽可能地准确）。这是一个好方法吗？

I want to get the milliseconds time of a system (I don't care if it's the real time, I want it to be as accurate as possible). Is this a good method to do it?

#ifdef WIN32
unsigned long long freq;
unsigned long long get_ms_time() {
    LARGE_INTEGER t;
    QueryPerformanceCounter(&t);
    return t.QuadPart / freq;
}
#else
unsigned long long get_ms_time() {
    struct timespec t;
    clock_gettime(CLOCK_MONOTONIC, &t);
    return t.tv_sec * 1000 + t.tv_nsec / 1000000;
}
#endif

如何将此值包装为带符号的int ？我尝试这样做，但得到了负值（在Linux上，我在Windows上不知道）：

How can I wrap this value to a signed int? I tried doing this and I get negative values like this (on Linux, I don't know on Windows):

~ start
-2083002438
~ 15 seconds after..
-2082987440
~ 15 seconds after..
-2082972441

我会这样。
〜开始
X
〜15秒后..
X + 14998
〜15秒后..
X + 29997

I would something like this. ~ start X ~ 15 seconds after.. X + 14998 ~ 15 seconds after.. X + 29997

其中X是一个正数。 （我希望输出为正并增加）

Where X is a positive number. (I want the output positive and increasing)

推荐答案

我在我的代码中做了类似的事情...

I do something like this in my code...

timespec specStart, specStop;

// Get start time ( UNIX timestamp ) in seconds...
clock_gettime( CLOCK_MONOTONIC_RAW, &startTime );

int startTimeInt = startTime.tv_sec;
std::cout << "start time : " << startTimeInt << std::endl;

...
// Get stop time ( UNIX timestamp ) in seconds...
clock_gettime( CLOCK_MONOTONIC_RAW, &stopTime );

int stopTimeInt = stopTime.tv_sec;
std::cout << "stop time : " << stopTimeInt << std::endl;

// Get time diff from stop time to start time
unsigned long long timeStart = specStart.tv_sec * 1000000000 + specStart.tv_nsec;
unsigned long long timeStop = specStop.tv_sec * 1000000000 + specStop.tv_nsec;
unsigned long long timeDelta = timeStio - timeStart; // Time diff in nanoseconds. 

int microSec = timeDelate / 1000; 
int mSec = timeDelta / 1000000;
int sec = timeDelta / 1000000000;

std::cout << "time diff : " << std::endl
    << sec << " s" << std::endl
    << msec << " ms" << std::endl
    << microSec << " µs" << std::endl
    << timeDelta << " ns" << std::endl;

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