f8768d2a1a
asctime.c: * Set errno to EINVAL and return "??? ??? ?? ??:??:?? ????\n" if asctime_r is called with a NULL struct tm pointer. (Note that asctime_r is called by ctime_r and asctime; asctime is called by ctime.) localtime.c: * Set errno to EINVAL and return WRONG if time1 is called with a NULL struct tm pointer; avoid dereference if a NULL struct tm pointer is passed to timelocal, timegm, or timeoff. (Note that time1 is called by mktime, timegm, and timeoff; mktime is called by timelocal.) * more core-avoidance work * Change to set timezone and altzone based on time types with greatest transition times (for the benefit of Asia/Seoul). zic.8: * Warning about case-sensitivity of names, but not of abbrevations zic.c: * Conditionally output extra types with most-recently-use offsets last (for use by systems with pre-2011 versions of localtime.c, helping to ensure that globals "altzone and "timezone" get set correctly). The code has been running for nearly four weeks on my laptop running FreeBSD 8.1 without a problem. MFC after: 1 month
469 lines
13 KiB
Groff
469 lines
13 KiB
Groff
.\" $FreeBSD$
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.Dd June 20, 2004
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.Dt ZIC 8
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.Os
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.Sh NAME
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.Nm zic
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.Nd timezone compiler
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.Sh SYNOPSIS
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.Nm
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.Op Fl -version
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.Op Fl Dsv
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.Op Fl d Ar directory
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.Op Fl g Ar group
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.Op Fl L Ar leapsecondfilename
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.Op Fl l Ar localtime
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.Op Fl m Ar mode
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.Op Fl p Ar posixrules
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.Op Fl u Ar user
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.Op Fl y Ar command
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.Op Ar filename ...
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.Sh DESCRIPTION
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The
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.Nm
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utility reads text from the file(s) named on the command line
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and creates the time conversion information files specified in this input.
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If a
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.Ar filename
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is
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.Em - ,
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the standard input is read.
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.Pp
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The following options are available:
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.Bl -tag -width indent
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.It Fl -version
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Output version information and exit.
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.It Fl D
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Do not automatically create directories.
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If the input file(s) specify
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an output file in a directory which does not already exist, the
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default behavior is to attempt to create the directory.
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If
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.Fl D
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is specified,
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.Nm
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will instead error out immediately.
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.It Fl d Ar directory
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Create time conversion information files in the named directory rather than
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in the standard directory named below.
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.It Fl g Ar group
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After creating each output file, change its group ownership to the
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specified
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.Ar group
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(which can be either a name or a numeric group ID).
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.It Fl L Ar leapsecondfilename
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Read leap second information from the file with the given name.
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If this option is not used,
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no leap second information appears in output files.
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.It Fl l Ar timezone
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Use the given
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.Ar time zone
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as local time.
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The
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.Nm
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utility will act as if the input contained a link line of the form
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.Pp
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.D1 No "Link timezone localtime"
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.Pp
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(Note that this action has no effect on
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.Fx ,
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since the local time zone is specified in
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.Pa /etc/localtime
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and not
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.Pa /usr/share/zoneinfo/localtime . )
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.It Fl m Ar mode
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After creating each output file, change its access mode to
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.Ar mode .
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Both numeric and alphabetic modes are accepted
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(see
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.Xr chmod 1 ) .
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.It Fl p Ar timezone
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Use the given
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.Ar "time zone" Ns 's
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rules when handling POSIX-format
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time zone environment variables.
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The
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.Nm
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utility will act as if the input contained a link line of the form
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.Pp
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.D1 No "Link timezone posixrules"
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.It Fl u Ar user
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After creating each output file, change its owner to
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.Ar user
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(which can be either a name or a numeric user ID).
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.It Fl v
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Complain if a year that appears in a data file is outside the range
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of years representable by
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.Xr time 3
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values.
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.It Fl s
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Limit time values stored in output files to values that are the same
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whether they are taken to be signed or unsigned.
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You can use this option to generate SVVS-compatible files.
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.It Fl y Ar command
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Use the given
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.Ar command
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rather than
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.Em yearistype
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when checking year types (see below).
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.El
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.Pp
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Input lines are made up of fields.
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Fields are separated from one another by any number of white space characters.
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Leading and trailing white space on input lines is ignored.
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An unquoted sharp character (#) in the input introduces a comment which extends
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to the end of the line the sharp character appears on.
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White space characters and sharp characters may be enclosed in double quotes
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(") if they are to be used as part of a field.
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Any line that is blank (after comment stripping) is ignored.
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Non-blank lines are expected to be of one of three types:
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rule lines, zone lines, and link lines.
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.Pp
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Names (such as month names) must be in English and are case insensitive.
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Abbreviations, if used, must be unambiguous in context.
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.Pp
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A rule line has the form:
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.Dl "Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S"
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For example:
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.Dl "Rule US 1967 1973 \- Apr lastSun 2:00 1:00 D"
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.Pp
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The fields that make up a rule line are:
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.Bl -tag -width "LETTER/S" -offset indent
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.It NAME
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Give the (arbitrary) name of the set of rules this rule is part of.
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.It FROM
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Give the first year in which the rule applies.
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Any integer year can be supplied; the Gregorian calendar is assumed.
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The word
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.Em minimum
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(or an abbreviation) means the minimum year representable as an integer.
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The word
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.Em maximum
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(or an abbreviation) means the maximum year representable as an integer.
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Rules can describe times that are not representable as time values,
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with the unrepresentable times ignored; this allows rules to be portable
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among hosts with differing time value types.
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.It TO
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Give the final year in which the rule applies.
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In addition to
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.Em minimum
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and
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.Em maximum
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(as above),
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the word
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.Em only
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(or an abbreviation)
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may be used to repeat the value of the
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.Em FROM
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field.
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.It TYPE
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Give the type of year in which the rule applies.
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If
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.Em TYPE
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is
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.Em \-
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then the rule applies in all years between
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.Em FROM
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and
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.Em TO
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inclusive.
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If
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.Em TYPE
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is something else, then
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.Nm
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executes the command
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.Li yearistype Ar year Ar type
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to check the type of a year:
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an exit status of zero is taken to mean that the year is of the given type;
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an exit status of one is taken to mean that the year is not of the given type.
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.It IN
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Name the month in which the rule takes effect.
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Month names may be abbreviated.
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.It ON
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Give the day on which the rule takes effect.
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Recognized forms include:
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.Pp
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.Bl -tag -width lastSun -compact -offset indent
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.It \&5
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the fifth of the month
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.It lastSun
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the last Sunday in the month
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.It lastMon
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the last Monday in the month
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.It Sun>=8
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first Sunday on or after the eighth
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.It Sun<=25
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last Sunday on or before the 25th
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.El
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.Pp
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Names of days of the week may be abbreviated or spelled out in full.
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Note that there must be no spaces within the
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.Em ON
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field.
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.It AT
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Give the time of day at which the rule takes effect.
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Recognized forms include:
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.Pp
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.Bl -tag -width "\&1:28:14" -offset indent -compact
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.It 2
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time in hours
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.It 2:00
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time in hours and minutes
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.It 15:00
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24-hour format time (for times after noon)
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.It 1:28:14
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time in hours, minutes, and seconds
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.El
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.Pp
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where hour 0 is midnight at the start of the day,
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and hour 24 is midnight at the end of the day.
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Any of these forms may be followed by the letter
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.Sq Li w
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if the given time is local
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.Dq "wall clock"
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time,
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.Sq Li s
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if the given time is local
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.Dq standard
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time, or
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.Sq Li u
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(or
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.Sq Li g
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or
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.Sq Li z )
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if the given time is universal time;
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in the absence of an indicator,
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wall clock time is assumed.
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.It SAVE
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Give the amount of time to be added to local standard time when the rule is in
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effect.
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This field has the same format as the
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.Em AT
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field
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(although, of course, the
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.Sq Li w
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and
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.Sq Li s
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suffixes are not used).
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.It LETTER/S
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Give the
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.Dq "variable part"
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(for example, the
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.Dq S
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or
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.Dq D
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in
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.Dq EST
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or
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.Dq EDT )
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of time zone abbreviations to be used when this rule is in effect.
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If this field is
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.Em \- ,
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the variable part is null.
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.El
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.Pp
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A zone line has the form:
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.Dl "Zone NAME GMTOFF RULES/SAVE FORMAT [UNTILYEAR [MONTH [DAY [TIME]]]]"
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For example:
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.Dl "Zone Australia/Adelaide 9:30 Aus CST 1971 Oct 31 2:00"
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The fields that make up a zone line are:
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.Bl -tag -width indent
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.It NAME
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The name of the time zone.
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This is the name used in creating the time conversion information file for the
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zone.
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.It GMTOFF
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The amount of time to add to UTC to get standard time in this zone.
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This field has the same format as the
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.Em AT
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and
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.Em SAVE
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fields of rule lines;
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begin the field with a minus sign if time must be subtracted from UTC.
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.It RULES/SAVE
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The name of the rule(s) that apply in the time zone or,
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alternately, an amount of time to add to local standard time.
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If this field is
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.Em \-
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then standard time always applies in the time zone.
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.It FORMAT
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The format for time zone abbreviations in this time zone.
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The pair of characters
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.Em %s
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is used to show where the
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.Dq "variable part"
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of the time zone abbreviation goes.
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Alternately,
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a slash (/)
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separates standard and daylight abbreviations.
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.It UNTILYEAR [MONTH [DAY [TIME]]]
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The time at which the UTC offset or the rule(s) change for a location.
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It is specified as a year, a month, a day, and a time of day.
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If this is specified,
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the time zone information is generated from the given UTC offset
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and rule change until the time specified.
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The month, day, and time of day have the same format as the IN, ON, and AT
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fields of a rule; trailing fields can be omitted, and default to the
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earliest possible value for the missing fields.
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.Pp
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The next line must be a
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.Dq continuation
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line; this has the same form as a zone line except that the
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string
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.Dq Zone
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and the name are omitted, as the continuation line will
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place information starting at the time specified as the
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.Em until
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information in the previous line in the file used by the previous line.
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Continuation lines may contain
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.Em until
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information, just as zone lines do, indicating that the next line is a further
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continuation.
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.El
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.Pp
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A link line has the form
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.Dl "Link LINK-FROM LINK-TO"
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For example:
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.Dl "Link Europe/Istanbul Asia/Istanbul"
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The
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.Em LINK-FROM
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field should appear as the
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.Em NAME
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field in some zone line;
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the
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.Em LINK-TO
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field is used as an alternate name for that zone.
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.Pp
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Except for continuation lines,
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lines may appear in any order in the input.
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.Pp
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Lines in the file that describes leap seconds have the following form:
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.Dl "Leap YEAR MONTH DAY HH:MM:SS CORR R/S"
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For example:
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.Dl "Leap 1974 Dec 31 23:59:60 + S"
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The
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.Em YEAR ,
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.Em MONTH ,
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.Em DAY ,
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and
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.Em HH:MM:SS
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fields tell when the leap second happened.
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The
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.Em CORR
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field
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should be
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.Dq +
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if a second was added
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or
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.Dq -
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if a second was skipped.
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.\" There's no need to document the following, since it's impossible for more
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.\" than one leap second to be inserted or deleted at a time.
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.\" The C Standard is in error in suggesting the possibility.
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.\" See Terry J Quinn, The BIPM and the accurate measure of time,
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.\" Proc IEEE 79, 7 (July 1991), 894-905.
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.\" or
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.\" .q ++
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.\" if two seconds were added
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.\" or
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.\" .q --
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.\" if two seconds were skipped.
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The
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.Em R/S
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field
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should be (an abbreviation of)
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.Dq Stationary
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if the leap second time given by the other fields should be interpreted as UTC
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or
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(an abbreviation of)
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.Dq Rolling
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if the leap second time given by the other fields should be interpreted as
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local wall clock time.
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.Sh "EXTENDED EXAMPLE"
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Here is an extended example of
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.Nm
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input, intended to illustrate many of its features.
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.br
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.ne 22
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.nf
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.in +2m
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.ta \w'# Rule\0\0'u +\w'NAME\0\0'u +\w'FROM\0\0'u +\w'1973\0\0'u +\w'TYPE\0\0'u +\w'Apr\0\0'u +\w'lastSun\0\0'u +\w'2:00\0\0'u +\w'SAVE\0\0'u
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.sp
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# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
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Rule Swiss 1940 only - Nov 2 0:00 1:00 S
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Rule Swiss 1940 only - Dec 31 0:00 0 -
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Rule Swiss 1941 1942 - May Sun>=1 2:00 1:00 S
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Rule Swiss 1941 1942 - Oct Sun>=1 0:00 0
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.sp .5
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Rule EU 1977 1980 - Apr Sun>=1 1:00u 1:00 S
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Rule EU 1977 only - Sep lastSun 1:00u 0 -
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Rule EU 1978 only - Oct 1 1:00u 0 -
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Rule EU 1979 1995 - Sep lastSun 1:00u 0 -
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Rule EU 1981 max - Mar lastSun 1:00u 1:00 S
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Rule EU 1996 max - Oct lastSun 1:00u 0 -
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.sp
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.ta \w'# Zone\0\0'u +\w'Europe/Zurich\0\0'u +\w'0:34:08\0\0'u +\w'RULES/SAVE\0\0'u +\w'FORMAT\0\0'u
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# Zone NAME GMTOFF RULES FORMAT UNTIL
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Zone Europe/Zurich 0:34:08 - LMT 1848 Sep 12
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0:29:44 - BMT 1894 Jun
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1:00 Swiss CE%sT 1981
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1:00 EU CE%sT
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.sp
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Link Europe/Zurich Switzerland
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.sp
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.in
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.fi
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In this example, the zone is named Europe/Zurich but it has an alias
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as Switzerland.
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Zurich was 34 minutes and 8 seconds west of GMT until 1848-09-12
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at 00:00, when the offset changed to 29 minutes and 44 seconds.
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After 1894-06-01 at 00:00 Swiss daylight saving rules (defined with
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lines beginning with "Rule Swiss") apply, and the GMT offset became
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one hour.
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From 1981 to the present, EU daylight saving rules have applied,
|
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and the UTC offset has remained at one hour.
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.Pp
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In 1940, daylight saving time applied from November 2 at 00:00 to
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December 31 at 00:00.
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In 1941 and 1942, daylight saving time applied from the first Sunday
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in May at 02:00 to the first Sunday in October at 00:00.
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The pre-1981 EU daylight-saving rules have no effect here, but are
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included for completeness.
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Since 1981, daylight saving has begun on the last Sunday in March
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at 01:00 UTC.
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Until 1995 it ended the last Sunday in September at 01:00 UTC, but
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this changed to the last Sunday in October starting in 1996.
|
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.Pp
|
|
For purposes of display, "LMT" and "BMT" were initially used,
|
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respectively.
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Since Swiss rules and later EU rules were applied, the display name
|
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for the timezone has been CET for standard time and CEST for daylight
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saving time.
|
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.Sh NOTES
|
|
For areas with more than two types of local time,
|
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you may need to use local standard time in the
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.Em AT
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field of the earliest transition time's rule to ensure that
|
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the earliest transition time recorded in the compiled file is correct.
|
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.Pp
|
|
If, for a particular zone, a clock advance caused by the start of
|
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daylight saving coincides with and is equal to a clock retreat
|
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caused by a change in UTC offset,
|
|
.Nm
|
|
produces a single transition to daylight saving at the new UTC offset
|
|
(without any change in wall clock time).
|
|
To get separate transitions use multiple zone continuation lines
|
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specifying transition instants using universal time.
|
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.Sh FILES
|
|
.Bl -tag -width /usr/share/zoneinfo -compact
|
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.It /usr/share/zoneinfo
|
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standard directory used for created files
|
|
.El
|
|
.Sh "SEE ALSO"
|
|
.Xr ctime 3 ,
|
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.Xr tzfile 5 ,
|
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.Xr zdump 8
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.\" @(#)zic.8 8.6
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.\" This file is in the public domain, so clarified as of
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.\" 2009-05-17 by Arthur David Olson.
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