.TH datetime 3

.SH NAME

datetime \- convert between TAI labels and seconds

.SH SYNTAX

.B #include <datetime.h>

void \fBdatetime_tai\fP(&\fIdt\fR,\fIt\fR);

datetime_sec \fBdatetime_untai\fP(&\fIdt\fR);

struct datetime \fIdt\fR;

.br

datetime_sec \fIt\fR;

.SH 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

.IR dt ,

stores a TAI label.

.I dt\fB.year

is the year number minus 1900;

.I dt\fB.mon

is the month number, from 0 (January) through 11 (December);

.I dt\fB.mday

is the day of the month, from 1 through 31;

.I dt\fB.hour

is the hour, from 0 through 23;

.I dt\fB.min

is the minute, from 0 through 59;

.I dt\fB.sec

is the second, from 0 through 59;

.I dt\fB.wday

is the day of the week, from 0 (Sunday) through 6 (Saturday);

.I dt\fB.yday

is the day of the year, from 0 through 365.

The

.B datetime

library supports more convenient TAI manipulation with

the datetime_sec type.

A datetime_sec value, such as

.IR t ,

is an integer referring to the

.IR t th

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.

.B datetime_tai

converts a datetime_sec to a TAI label.

.B datetime_untai

reads a TAI label

(specifically

.IR dt\fB.year ,

.IR dt\fB.mon ,

.IR dt\fB.mday ,

.IR dt\fB.hour ,

.IR dt\fB.min ,

and

.IR dt\fB.sec )

and returns a datetime_sec.

.SH "SEE ALSO"

now(3)