datetime.3 (1611B)
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)