if (l == 0) { sprintf (buf, "????-??-?? ??:??:??"); return buf; }
get_timestamp (time_t l){    static char buf[64];    struct tm * tm;    tm = localtime (&l);    sprintf (buf, "%04d-%02d-%02d %02d:%02d:%02d",	     tm->tm_year+1900, tm->tm_mon+1, tm->tm_mday,	     tm->tm_hour, tm->tm_min, tm->tm_sec);    return buf;}