/*

     Linux c 計算時間差

     功能:可計算毫秒和微秒的時間差

     資料來源:http://blog.jeoygin.org/2012/03/c-get-time-millisecond.html

*/

#include <stdio.h>

#include <sys/time.h>

#include <unistd.h>// sleep(3);

#include <sys/timeb.h>//timeb

 long long getSystemTime() {

    struct timeb t;

    ftime(&t);

    return 1000 * t.time + t.millitm;

}

int main() {

    struct timeval start, end;

    gettimeofday( &start, NULL );

    sleep(3);

    gettimeofday( &end, NULL );

    int timeuse = 1000000 * ( end.tv_sec - start.tv_sec ) + end.tv_usec - start.tv_usec;

    printf("time: %d us\n", timeuse);

////////////////////////////////////////////////////////////

    long long start1=getSystemTime();

    sleep(3);

    long long end1=getSystemTime();

    printf("time: %lld ms\n", end1-start1);

    return 0;

}