1 .TH datetime 3

     2 .SH NAME

     3 datetime \- convert between TAI labels and seconds

     4 .SH SYNTAX

     5 .B #include <datetime.h>

     6 

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

     8 

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

    10 

    11 struct datetime \fIdt\fR;

    12 .br

    13 datetime_sec \fIt\fR;

    14 .SH DESCRIPTION

    15 International Atomic Time, TAI,

    16 is the fundamental unit for time measurements.

    17 TAI has one label for every second of real time,

    18 without complications such as leap seconds.

    19 

    20 A

    21 struct datetime

    22 variable,

    23 such as

    24 .IR dt ,

    25 stores a TAI label.

    26 .I dt\fB.year

    27 is the year number minus 1900;

    28 .I dt\fB.mon

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

    30 .I dt\fB.mday

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

    32 .I dt\fB.hour

    33 is the hour, from 0 through 23;

    34 .I dt\fB.min

    35 is the minute, from 0 through 59;

    36 .I dt\fB.sec

    37 is the second, from 0 through 59;

    38 .I dt\fB.wday

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

    40 .I dt\fB.yday

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

    42 

    43 The

    44 .B datetime

    45 library supports more convenient TAI manipulation with

    46 the datetime_sec type.

    47 A datetime_sec value, such as

    48 .IR t ,

    49 is an integer referring to the

    50 .IR t th

    51 second after the beginning of 1970 TAI.

    52 The first second of 1970 TAI was 0;

    53 the next second was 1;

    54 the last second of 1969 TAI was -1.

    55 The difference between two datetime_sec values is a number

    56 of real-time seconds.

    57 

    58 .B datetime_tai

    59 converts a datetime_sec to a TAI label.

    60 

    61 .B datetime_untai

    62 reads a TAI label

    63 (specifically

    64 .IR dt\fB.year ,

    65 .IR dt\fB.mon ,

    66 .IR dt\fB.mday ,

    67 .IR dt\fB.hour ,

    68 .IR dt\fB.min ,

    69 and

    70 .IR dt\fB.sec )

    71 and returns a datetime_sec.

    72 .SH "SEE ALSO"

    73 now(3)