( (tm->tm_year/4 - tm->tm_year/100 + tm->tm_year/400 + 367*tm->tm_mon/12 + tm->tm_mday) +tm->tm_year*365 - 719499 )*24
这个式子返回的就是小时数,不理解啊,怎么算的?
struct rtc_time {
int tm_sec;
int tm_min;
int tm_hour;
int tm_mday;
int tm_mon;
int tm_year;
int tm_wday;
};