如何使用Linux系统调用gettimeofday（）来衡量C进程所花费的时间？

Question

I'm trying to find how much time the process / function took to find the solution. I am asked to do it using gettimeofday() Linux System Call. Any help? Thanks in advance.

Answer 1

Here is my tested code snipped:

struct timeval t1, t2;
double elapsedTime;

// start timer
gettimeofday(&t1, NULL);

// do something
// ...

// stop timer
gettimeofday(&t2, NULL);

// compute and print the elapsed time in millisec
elapsedTime = (t2.tv_sec - t1.tv_sec) * 1000.0;      // sec to ms
elapsedTime += (t2.tv_usec - t1.tv_usec) / 1000.0;   // us to ms
fprintf(stderr, "elapsedTime = %5.3fms \n", elapsedTime);

Hope that helps.