datetime(3)            C Library Functions            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 (Satur-
     day); dt.yday is the day of the year, from 0 through 365.

     The datetime library supports more convenient TAI  manipula-
     tion 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)