출처:http://www.gnu.org/software/libc/manual/html_node/Elapsed-Time.html
#include <stdio.h>
#include <sys/time.h>
int main()
{
int i;
int ret;
struct timeval before , after, result;
gettimeofday(&before , NULL);
//Time taking task
for (i=1 ; i <= 100 ; i++)
{
printf("%d %d %d n",i, i*i, i*i*i);
usleep(i);
}
gettimeofday(&after , NULL);
ret = timeval_subtract(&result, &after , &before);
printf("ret=%d\n", ret);
printf("\n[%d] sec ", result.tv_sec);
printf("[%d] usec \n", result.tv_usec);
return 0;
}
inttimeval_subtract (result, x, y)
struct timeval *result, *x, *y;
{
/* Perform the carry for the later subtraction by updating y. */
if (x->tv_usec < y->tv_usec) {
int nsec = (y->tv_usec - x->tv_usec) / 1000000 + 1;
y->tv_usec -= 1000000 * nsec;
y->tv_sec += nsec;
}
if (x->tv_usec - y->tv_usec > 1000000) {
int nsec = (x->tv_usec - y->tv_usec) / 1000000;
y->tv_usec += 1000000 * nsec;
y->tv_sec -= nsec;
}
/* Compute the time remaining to wait.
tv_usec is certainly positive. */
result->tv_sec = x->tv_sec - y->tv_sec;
result->tv_usec = x->tv_usec - y->tv_usec;
/* Return 1 if result is negative. */
return x->tv_sec < y->tv_sec;
}
