debian man page for datetime

datetime(3)						     Library Functions Manual						       datetime(3)

NAME
       datetime - convert between TAI labels and seconds

SYNTAX
       #include <datetime.h>

       void datetime_tai(&dt,t);

       datetime_sec datetime_untai(&dt);

       struct datetime dt;
       datetime_sec t;

DESCRIPTION
       International  Atomic  Time,  TAI, is the fundamental unit for time measurements.  TAI has one label for every second of real time, without
       complications such as leap seconds.

       A struct datetime variable, such as dt, stores a TAI label.  dt.year is the year number minus 1900; dt.mon is  the  month  number,  from  0
       (January)  through 11 (December); dt.mday is the day of the month, from 1 through 31; dt.hour is the hour, from 0 through 23; dt.min is the
       minute, from 0 through 59; dt.sec is the second, from 0 through 59; dt.wday is the day of the week, from 0 (Sunday) through  6  (Saturday);
       dt.yday is the day of the year, from 0 through 365.

       The  datetime library supports more convenient TAI manipulation with the datetime_sec type.  A datetime_sec value, such as t, is an integer
       referring to the tth second after the beginning of 1970 TAI.  The first second of 1970 TAI was 0; the next second was 1; the last second of
       1969 TAI was -1.  The difference between two datetime_sec values is a number of real-time seconds.

       datetime_tai converts a datetime_sec to a TAI label.

       datetime_untai reads a TAI label (specifically dt.year, dt.mon, dt.mday, dt.hour, dt.min, and dt.sec) and returns a datetime_sec.

SEE ALSO
       now(3)

																       datetime(3)