tm

Structure holding a calendar date and time broken down into its components.

int tm_sec	seconds after the minute – [0, 61](until C99) / [0, 60] (since C99)^{[note 1]}
int tm_min	minutes after the hour – [0, 59]
int tm_hour	hours since midnight – [0, 23]
int tm_mday	day of the month – [1, 31]
int tm_mon	months since January – [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 Saving Time flag. The value is positive if DST is in effect, zero if not and negative if no information is available

↑ Range allows for a positive leap second. Two leap seconds in the same minute are not allowed (the C90 range 0..61 was a defect)