Thanks Martin, this is exactly what I need (clock_subr.h), I don't need all what struct tm provides,But can you explain why that struct is needed inside the kernel? It just makes no sense at all to me and I am curious :-) Of course there *are* parts of the kernel that deal with simmilar structures, like drivers for RTC and they use e.g. struct clock_ymdhms and there are a few conversion functions for them in src/sys/dev/clock_subr.h, like clock_sec_to_ymdhms() which takes seconds and converts it to year, month, day, hour, minute and seconds.
struct clock_ymdhms is sufficient.Converting from/to struct clock_ymdhms is used for firing fair usage policy event,
which can use weekday or monthday for checking transferred data. I.e. internet user needs to be notified about transferred data in last week. Peter