time_t time(time_t *timer); struct tm *localtime(const time_t *timer); Theheader file contains declarations of all relevant functions and externals. It also contains the tm structure, which includes the following members: int tm_sec; /* seconds after the minute - [0,61] */ int tm_min; /* minutes after the hour - [0,59] */ int tm_hour; /* hours - [0,23] */ int tm_mday; /* day of month - [1,31] */ int tm_mon; /* month of year - [0,11] */ int tm_year; /* years since 1900 */ int tm_wday; /* days since Sunday - [0,6] */ int tm_yday; /* days since January 1 - [0,365] */ int tm_isdst; /* daylight savings time flag */ The value of tm_isdst is positive if a summer time zone adjustment such as Daylight Savings Time is in effect, zero if not in effect, and negative if the information is not available.