linux 获取当前时间，精确到毫秒

linux下获取当前系统时间，代码如下：

void sysTime(void)
{
    struct timeval tv;
    struct timezone tz;   
    struct tm *t;
     
    gettimeofday(&tv, &tz);
    t = localtime(&tv.tv_sec);
    printf("time_now:%d-%d-%d %d:%d:%d.%ld\n", 1900+t->tm_year, 1+t->tm_mon, t->tm_mday, t->tm_hour, t->tm_min, t->tm_sec, tv.tv_usec);
}