ref: e81c54ba2ecc673a4d5f8aed0e9b52841fe07b0d
dir: /man/2/daytime/
.TH DAYTIME 2 .SH NAME daytime: text, filet, gmt, local, now, string2tm, time, tm2epoch \- time conversions .SH SYNOPSIS .EX include "daytime.m"; daytime := load Daytime Daytime->PATH; Tm: adt { sec: int; # seconds (0 to 59) min: int; # minutes (0 to 59) hour: int; # hours (0 to 23) mday: int; # day of the month (1 to 31) mon: int; # month (0 to 11) year: int; # year-1900; 2000AD is 100 wday: int; # day of week (0 to 6, Sunday is 0) yday: int; # day of year (0 to 365) zone: string; # time zone name tzoff: int; # time zone offset (seconds from GMT) }; text: fn(tm: ref Tm): string; filet: fn(now, t: int): string; gmt: fn(tim: int): ref Tm; local: fn(tim: int): ref Tm; now: fn(): int; time: fn(): string; tm2epoch: fn(tm: ref Tm): int; string2tm: fn(date: string): ref Tm; .EE .SH DESCRIPTION These routines perform time conversions relative to the epoch 00:00:00 GMT, Jan. 1, 1970. Note the range of values for each member of the .B Tm adt. The conventions are the same as those of C's .IR ctime . .PP .B Text converts a time structure referenced by .I tm from local or GMT time to a string in the format: .IP .B "Sat Jan 1 13:00:00 GMT 2000" .PP .B Filet converts the file access or modification time .I t from seconds since the epoch to local time as a string in the format: .IP .B "Jan 1 13:00" .PP if the file is less than 6 months old or .IP .B "Jan 1 2000" .PP if the file is older than 6 months, compared to the time .IR now . .PP .B Gmt converts seconds since the epoch, received in .IR tim , to a time structure in Greenwich Mean Time (GMT). .PP .B Local converts seconds since the epoch, received in .IR tim , to a time structure in local time. .PP .B Now returns the time in seconds since the epoch, obtained by reading .B /dev/time (see .IR cons (3)). .PP .B Time converts seconds since the epoch to the local time as a string in the format .BR "Fri May 19 17:01:36 BST 2000" . .PP .B Tm2epoch converts a time structure referenced by .I tm from local or GMT time to seconds since the epoch. .PP .B String2tm returns a reference to a .B Tm value corresponding to the date and time in textual form in string .IR s , which must have one of the forms below: .IP .EX Sun, 06 Nov 1994 08:49:37 GMT \fR(RFC822, RFC1123)\fP Sunday, 06-Nov-94 08:49:37 GMT \fR(RFC850)\fP Sun Nov 6 08:49:37 GMT 1994 \fR(output of \fPtext\fR, above)\fP .EE .PP A missing time zone in any format is assumed to be .BR GMT . .B String2tm returns nil if .I s is not correctly formed. .PP When local time is first requested, .B daytime reads a table for time zone conversion from the .B timezone environment variable, if that is set, and otherwise from the file .BR /locale/timezone , which is copied from one of the other files in .B /locale when the system is installed. The timezone table is a text file containing lines of space-separated fields. The first line gives the normal time zone name and its difference from GMT in seconds followed by an alternative time zone name (eg, for `daylight savings' or `summer' time) and its difference from GMT followed by a newline. The remainder is a list of pairs of times (seconds past the start of 1970, in the first time zone) when the alternative time zone applies. For example: .IP .EX EST -18000 EDT -14400 9943200 25664400 41392800 57718800 ... .EE .PP Greenwich Mean Time is represented by .IP .EX GMT 0 .EE .SH SOURCE .B /appl/lib/daytime.b .SH SEE ALSO .IR cons (3), .IR sys-millisec (2) .SH BUGS The sign bit of a Limbo integer holding a time will turn on 68 years from the epoch.