打印可讀格式精確到微妙的時間

   gettimeofday(&tv, NULL);
    //time(&caltime);
    TRACE("[AUDIT-TRACE] time of day sec %ld, usec %ld.\n", tv.tv_sec, tv.tv_usec);
    //tmptr = gmtime(&caltime);
    tmptr = localtime(&tv.tv_sec);
    snprintf(timeval_buf, sizeof(timeval_buf), "%.4d%.2d%.2d%.2d%.2d%.2d%.6ld",
        tmptr->tm_year + 1900,
        tmptr->tm_mon + 1,
        tmptr->tm_mday,
        tmptr->tm_hour,
        tmptr->tm_min,
        tmptr->tm_sec,
        tv.tv_usec);