The tm structure contains a representation of time 'broken down' into components of the Gregorian calendar.
The normal ranges of the elements are..
tm_sec seconds after the minute - [ 0 to 59 ]
tm_min minutes after the hour - [ 0 to 59 ]
tm_hour hours since midnight - [ 0 to 23 ]
tm_mday day of the month - [ 1 to 31 ]
tm_wday days since Sunday - [ 0 to 6 ]
tm_mon months since January - [ 0 to 11 ]
tm_year years since 1900
tm_yday days since January 1 - [ 0 to 365 ]
tm_isdst Daylight Saving Time flag *
The value of tm_isdst is zero if Daylight Saving Time is not in effect, and is negative if
the information is not available.
When Daylight Saving Time is in effect, the value represents the number of
seconds the clock is advanced.
See the set_dst() function for more information about Daylight Saving.
