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)