[英]millisecond precision timing of functions in C - crossplatform
Is there a way to get milliseconds precision, accurate (at least within a few ms) times in C using a cross-platform approach? 有没有办法使用跨平台方法在C中获得毫秒精度,准确度(至少在几毫秒内)?
on a POSIX system I can use sys/time.h, but that is not cross-platform. 在POSIX系统上我可以使用sys / time.h,但这不是跨平台的。
the stdlib time() function only gives second level precision stdlib time()函数仅提供二级精度
I haven't found a cross-platform solution to measuring time in C, per se. 我还没有找到一个跨平台的解决方案来测量C本身的时间。 However, what I do is use almost identical functions for Unix and Windows.
但是,我所做的是为Unix和Windows使用几乎相同的功能。 I created this gist because I always have to re-look this up every time.
我创造了这个要点因为我每次都要重新审视这个。 In short:
简而言之:
#include <time.h>
long diff_micro(struct timespec *start, struct timespec *end)
{
/* us */
return ((end->tv_sec * (1000000)) + (end->tv_nsec / 1000)) -
((start->tv_sec * 1000000) + (start->tv_nsec / 1000));
}
long diff_milli(struct timespec *start, struct timespec *end)
{
/* ms */
return ((end->tv_sec * 1000) + (end->tv_nsec / 1000000)) -
((start->tv_sec * 1000) + (start->tv_nsec / 1000000));
}
int main(int argc, char **argv)
{
struct timespec start, end;
clock_gettime(CLOCK_MONOTONIC, &start);
// Activity to be timed
sleep(1000);
clock_gettime(CLOCK_MONOTONIC, &end);
printf("%ld us\n", diff_micro(&start, &end));
printf("%ld ms\n", diff_milli(&start, &end));
return 0;
}
source for Unix solution Unix解决方案的源代码
#include <Windows.h>
long diff_micro(LARGE_INTEGER *start, LARGE_INTEGER *end)
{
LARGE_INTEGER Frequency, elapsed;
QueryPerformanceFrequency(&Frequency);
elapsed.QuadPart = end->QuadPart - start->QuadPart;
elapsed.QuadPart *= 1000000;
elapsed.QuadPart /= Frequency.QuadPart;
return elapsed.QuadPart;
}
long diff_milli(LARGE_INTEGER *start, LARGE_INTEGER *end)
{
LARGE_INTEGER Frequency, elapsed;
QueryPerformanceFrequency(&Frequency);
elapsed.QuadPart = end->QuadPart - start->QuadPart;
elapsed.QuadPart *= 1000;
elapsed.QuadPart /= Frequency.QuadPart;
return elapsed.QuadPart;
}
int main(int argc, char **argv)
{
LARGE_INTEGER StartingTime, EndingTime;
QueryPerformanceCounter(&StartingTime);
// Activity to be timed
Sleep(1000);
QueryPerformanceCounter(&EndingTime);
printf("%ld us\n", diff_micro(&StartingTime, &EndingTime));
printf("%ld ms\n", diff_milli(&StartingTime, &EndingTime));
return 0;
}
The best way is using std::chrono 最好的方法是使用std :: chrono
#include <chrono>
...
auto begin = std::chrono::high_resolution_clock::now();
...
auto end = std::chrono::high_resolution_clock::now();
elapsedTime = std::chrono::duration_cast<std::chrono::milliseconds>(end - begin).count();
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