C语言获取时间戳

iostream
stdlib.h
stdio.h
sys/time.h
unistd.h

int main(){
    struct timeval tv;
    gettimeofday(&tv,NULL);
    printf("second:%ld\n",tv.tv_sec);  //秒
    printf("millisecond:%ld\n",tv.tv_sec*1000 + tv.tv_usec/1000);  //毫秒
    printf("microsecond:%ld\n",tv.tv_sec*1000000 + tv.tv_usec);  //微秒

    sleep(3); // 为方便观看，让程序睡三秒后对比
    std::cout << "3s later:" << std::endl;

    gettimeofday(&tv,NULL);
    printf("second:%ld\n",tv.tv_sec);  //秒
    printf("millisecond:%ld\n",tv.tv_sec*1000 + tv.tv_usec/1000);  //毫秒
    printf("microsecond:%ld\n",tv.tv_sec*1000000 + tv.tv_usec);  //微秒
    return 0;
}

struct timeval
{     long tv_sec; //秒      long tv_usec; //微秒  };