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File: [cvs.NetBSD.org] / src / lib / libc / time / tzselect.8 (download)

Revision 1.8, Fri Oct 19 23:05:35 2018 UTC (2 years, 1 month ago) by christos
Branch: MAIN
CVS Tags: phil-wifi-20200421, phil-wifi-20200411, phil-wifi-20200406, phil-wifi-20191119, phil-wifi-20190609, pgoyette-compat-20190127, pgoyette-compat-20190118, pgoyette-compat-1226, pgoyette-compat-1126, pgoyette-compat-1020, netbsd-9-base, netbsd-9-1-RELEASE, netbsd-9-0-RELEASE, netbsd-9-0-RC2, netbsd-9-0-RC1, netbsd-9, is-mlppp-base, is-mlppp
Changes since 1.7: +7 -7 lines

Update to 2018f:

  Changes to code

    zic now always generates TZif files where time type 0 is used for
    timestamps before the first transition.  This simplifies the
    reading of TZif files and should not affect behavior of existing
    TZif readers because the same set of time types is used; only
    their internal indexes may have changed.  This affects only the
    legacy zones EST5EDT, CST6CDT, MST7MDT, PST8PDT, CET, MET, and
    EET, which previously used nonzero types for these timestamps.

    Because of the type 0 change, zic no longer outputs a dummy
    transition at time -2**59 (before the Big Bang), as clients should
    no longer need this to handle historical timestamps correctly.
    This reverts a change introduced in 2013d and shrinks most TZif
    files by a few bytes.

    zic now supports negative time-of-day in Rule and Leap lines, e.g.,
    "Rule X min max - Apr lastSun -6:00 1:00 -" means the transition
    occurs at 18:00 on the Saturday before the last Sunday in April.
    This behavior was documented in 2018a but the code did not
    entirely match the documentation.

    localtime.c no longer requires at least one time type in TZif
    files that lack transitions or have a POSIX-style TZ string.  This
    future-proofs the code against possible future extensions to the
    format that would allow TZif files with POSIX-style TZ strings and
    without transitions or time types.

    A read-access subscript error in localtime.c has been fixed.
    It could occur only in TZif files with timecnt == 0, something that
    does not happen in practice now but could happen in future versions.

    localtime.c no longer ignores TZif POSIX-style TZ strings that
    specify only standard time.  Instead, these TZ strings now
    override the default time type for timestamps after the last
    transition (or for all time stamps if there are no transitions),
    just as DST strings specifying DST have always done.

    leapseconds.awk now outputs "#updated" and "#expires" comments,
    and supports leap seconds at the ends of months other than June
    and December.  (Inspired by suggestions from Chris Woodbury.)

  Changes to documentation

    New restrictions: A Rule name must start with a character that
    is neither an ASCII digit nor "-" nor "+", and an unquoted name
    should not use characters in the set "!$%&'()*,/:;<=>?@[\]^`{|}~".
    The latter restriction makes room for future extensions (a
    possibility noted by Tom Lane).

    tzfile.5 now documents what time types apply before the first and
    after the last transition, if any.

    Documentation now uses the spelling "timezone" for a TZ setting
    that determines timestamp history, and "time zone" for a
    geographic region currently sharing the same standard time.

    The name "TZif" is now used for the tz binary data format.

    tz-link.htm now mentions the A0 TimeZone Migration utilities.
    (Thanks to Aldrin Martoq for the link.)

.\"	$NetBSD: tzselect.8,v 1.8 2018/10/19 23:05:35 christos Exp $
tzselect \- select a timezone
.ie \n(.g .ds - \f(CW-\fP
.el ds - \-
.B tzselect
.B \*-c
.I coord
] [
.B \*-n
.I limit
] [
.B \*-\*-help
] [
.B \*-\*-version
.B tzselect
program asks the user for information about the current location,
and outputs the resulting timezone to standard output.
The output is suitable as a value for the TZ environment variable.
All interaction with the user is done via standard input and standard error.
.BI "\*-c " coord
Instead of asking for continent and then country and then city,
ask for selection from time zones whose largest cities
are closest to the location with geographical coordinates
.I coord.
Use ISO 6709 notation for
.I coord,
that is, a latitude immediately followed by a longitude.  The latitude
and longitude should be signed integers followed by an optional
decimal point and fraction: positive numbers represent north and east,
negative south and west.  Latitudes with two and longitudes with three
integer digits are treated as degrees; latitudes with four or six and
longitudes with five or seven integer digits are treated as
and zero or
seconds, with any trailing fractions represent fractional minutes or
is present) seconds.  The decimal point is that of the current locale.
For example, in the (default) C locale,
.B "\*-c\ +40.689\*-074.045"
specifies 40.689\(de\|N, 74.045\(de\|W,
.B "\*-c\ +4041.4\*-07402.7"
specifies 40\(de\|41.4\(fm\|N, 74\(de\|2.7\(fm\|W, and
.B "\*-c\ +404121\*-0740240"
specifies 40\(de\|41\(fm\|21\(sd\|N, 74\(de\|2\(fm\|40\(sd\|W.
.I coord
is not one of the documented forms, the resulting behavior is unspecified.
.BI "\*-n " limit
.B \*-c
is used, display the closest
.I limit
locations (default 10).
.B "\*-\*-help"
Output help information and exit.
.B "\*-\*-version"
Output version information and exit.
Name of a Posix-compliant
.I awk
program (default:
.BR awk ).
Name of the directory containing timezone data files (default:
.BR /usr/share/zoneinfo ).
Table of ISO 3166 2-letter country codes and country names.
Table of country codes, latitude and longitude, timezones, and
descriptive comments.
Timezone data file for timezone \f2TZ\fP.
The exit status is zero if a timezone was successfully obtained from the user,
nonzero otherwise.
newctime(3), tzfile(5), zdump(8), zic(8)
Applications should not assume that
.BR tzselect 's
output matches the user's political preferences.
.\" @(#)tzselect.8	8.2
.\" This file is in the public domain, so clarified as of
.\" 2009-05-17 by Arthur David Olson.