diff options
| author | Philip Paeps <philip@FreeBSD.org> | 2022-08-16 07:24:21 +0000 |
|---|---|---|
| committer | Philip Paeps <philip@FreeBSD.org> | 2022-08-16 07:24:21 +0000 |
| commit | 9b5369d383baf54651be0922591eeb6263ce029d (patch) | |
| tree | b1cd2f21627ee78ae3e40234e7530e3a65b8c212 /newtzset.3 | |
| parent | 157c2da9c527cd9ebae03b07bdae90e474d5a403 (diff) | |
Unsplit vendor import of tzcode 2010nvendor/tzcode/unsplit
Historically, to work around CVS limitations, imports on the tzcode
vendor branch were split into subdirectories, which were then merged to
their respective counterparts in contrib. In the Git era, this split is
unnecessary and adds more work.
Undo the split for the most recent vendor import of tzcode 2010n to
prepare for the vendor import of tzcode 2022c.
Diffstat (limited to 'newtzset.3')
| -rw-r--r-- | newtzset.3 | 239 |
1 files changed, 239 insertions, 0 deletions
diff --git a/newtzset.3 b/newtzset.3 new file mode 100644 index 000000000000..07c5e0c605a7 --- /dev/null +++ b/newtzset.3 @@ -0,0 +1,239 @@ +.TH NEWTZSET 3 +.SH NAME +tzset \- initialize time conversion information +.SH SYNOPSIS +.nf +.B void tzset() +.PP +.B cc ... -ltz +.fi +.SH DESCRIPTION +.I Tzset +uses the value of the environment variable +.B TZ +to set time conversion information used by +.IR localtime . +If +.B TZ +does not appear in the environment, +the best available approximation to local wall clock time, as specified +by the +.IR tzfile (5)-format +file +.B localtime +in the system time conversion information directory, is used by +.IR localtime . +If +.B TZ +appears in the environment but its value is a null string, +Coordinated Universal Time (UTC) is used (without leap second +correction). If +.B TZ +appears in the environment and its value is not a null string: +.IP +if the value begins with a colon, it is used as a pathname of a file +from which to read the time conversion information; +.IP +if the value does not begin with a colon, it is first used as the +pathname of a file from which to read the time conversion information, +and, if that file cannot be read, is used directly as a specification of +the time conversion information. +.PP +When +.B TZ +is used as a pathname, if it begins with a slash, +it is used as an absolute pathname; otherwise, +it is used as a pathname relative to a system time conversion information +directory. +The file must be in the format specified in +.IR tzfile (5). +.PP +When +.B TZ +is used directly as a specification of the time conversion information, +it must have the following syntax (spaces inserted for clarity): +.IP +\fIstd\|offset\fR[\fIdst\fR[\fIoffset\fR][\fB,\fIrule\fR]] +.PP +Where: +.RS +.TP 15 +.IR std " and " dst +Three or more bytes that are the designation for the standard +.RI ( std ) +or summer +.RI ( dst ) +time zone. Only +.I std +is required; if +.I dst +is missing, then summer time does not apply in this locale. +Upper- and lowercase letters are explicitly allowed. Any characters +except a leading colon +.RB ( : ), +digits, comma +.RB ( , ), +minus +.RB ( \(mi ), +plus +.RB ( \(pl ), +and ASCII NUL are allowed. +.TP +.I offset +Indicates the value one must add to the local time to arrive at +Coordinated Universal Time. The +.I offset +has the form: +.RS +.IP +\fIhh\fR[\fB:\fImm\fR[\fB:\fIss\fR]] +.RE +.IP +The minutes +.RI ( mm ) +and seconds +.RI ( ss ) +are optional. The hour +.RI ( hh ) +is required and may be a single digit. The +.I offset +following +.I std +is required. If no +.I offset +follows +.IR dst , +summer time is assumed to be one hour ahead of standard time. One or +more digits may be used; the value is always interpreted as a decimal +number. The hour must be between zero and 24, and the minutes (and +seconds) \(em if present \(em between zero and 59. If preceded by a +.RB `` \(mi '', +the time zone shall be east of the Prime Meridian; otherwise it shall be +west (which may be indicated by an optional preceding +.RB `` \(pl ''). +.TP +.I rule +Indicates when to change to and back from summer time. The +.I rule +has the form: +.RS +.IP +\fIdate\fB/\fItime\fB,\fIdate\fB/\fItime\fR +.RE +.IP +where the first +.I date +describes when the change from standard to summer time occurs and the +second +.I date +describes when the change back happens. Each +.I time +field describes when, in current local time, the change to the other +time is made. +.IP +The format of +.I date +is one of the following: +.RS +.TP 10 +.BI J n +The Julian day +.I n +.RI "(1\ \(<=" "\ n\ " "\(<=\ 365). +Leap days are not counted; that is, in all years \(em including leap +years \(em February 28 is day 59 and March 1 is day 60. It is +impossible to explicitly refer to the occasional February 29. +.TP +.I n +The zero-based Julian day +.RI "(0\ \(<=" "\ n\ " "\(<=\ 365). +Leap days are counted, and it is possible to refer to February 29. +.TP +.BI M m . n . d +The +.IR d' th +day +.RI "(0\ \(<=" "\ d\ " "\(<=\ 6) +of week +.I n +of month +.I m +of the year +.RI "(1\ \(<=" "\ n\ " "\(<=\ 5, +.RI "1\ \(<=" "\ m\ " "\(<=\ 12, +where week 5 means ``the last +.I d +day in month +.IR m '' +which may occur in either the fourth or the fifth week). Week 1 is the +first week in which the +.IR d' th +day occurs. Day zero is Sunday. +.RE +.IP "" 15 +The +.I time +has the same format as +.I offset +except that no leading sign +.RB (`` \(mi '' +or +.RB `` \(pl '') +is allowed. The default, if +.I time +is not given, is +.BR 02:00:00 . +.RE +.LP +If no +.I rule +is present in +.BR TZ , +the rules specified +by the +.IR tzfile (5)-format +file +.B posixrules +in the system time conversion information directory are used, with the +standard and summer time offsets from UTC replaced by those specified by +the +.I offset +values in +.BR TZ . +.PP +For compatibility with System V Release 3.1, a semicolon +.RB ( ; ) +may be used to separate the +.I rule +from the rest of the specification. +.PP +If the +.B TZ +environment variable does not specify a +.IR tzfile (5)-format +and cannot be interpreted as a direct specification, +UTC is used. +.SH FILES +.ta \w'/usr/local/etc/zoneinfo/posixrules\0\0'u +/usr/local/etc/zoneinfo time zone information directory +.br +/usr/local/etc/zoneinfo/localtime local time zone file +.br +/usr/local/etc/zoneinfo/posixrules used with POSIX-style TZ's +.br +/usr/local/etc/zoneinfo/GMT for UTC leap seconds +.sp +If +.B /usr/local/etc/zoneinfo/GMT +is absent, +UTC leap seconds are loaded from +.BR /usr/local/etc/zoneinfo/posixrules . +.SH SEE ALSO +getenv(3), +newctime(3), +newstrftime(3), +time(2), +tzfile(5) +.\" @(#)newtzset.3 8.2 +.\" This file is in the public domain, so clarified as of +.\" 2009-05-17 by Arthur David Olson. |