DateTime::TimeZone::Tzfile - tzfile (zoneinfo) timezone files
use DateTime::TimeZone::Tzfile;
$tz = DateTime::TimeZone::Tzfile->new(
name => "local timezone",
filename => "/etc/localtime");
$tz = DateTime::TimeZone::Tzfile->new("/etc/localtime");
if($tz->is_floating) { ...
if($tz->is_utc) { ...
if($tz->is_olson) { ...
$category = $tz->category;
$tz_string = $tz->name;
if($tz->has_dst_changes) { ...
if($tz->is_dst_for_datetime($dt)) { ...
$offset = $tz->offset_for_datetime($dt);
$abbrev = $tz->short_name_for_datetime($dt);
$offset = $tz->offset_for_local_datetime($dt);
An instance of this class represents a timezone that was encoded
in a file in the tzfile(5) format. These can express arbitrary
patterns of offsets from Universal Time, changing over time. Offsets and
change times are limited to a resolution of one second.
This class implements the DateTime::TimeZone interface, so that
its instances can be used with DateTime objects.
- DateTime::TimeZone::Tzfile->new(ATTR
=> VALUE, ...)
- Reads and parses a tzfile(5) format file, then constructs and
returns a DateTime-compatible timezone object that implements the timezone
encoded in the file. The following attributes may be given:
- name
- Name for the timezone object. This will be returned by the
"name" method described below, and will
be included in certain error messages.
- category
- The string or "undef" that will be
returned by the "category" method
described below. Default "undef".
- is_olson
- The truth value that will be returned by the
"is_olson" method described below.
Default false.
- filename
- Name of the file from which to read the timezone data. The filename must
be understood by IO::File.
- filehandle
- An IO::Handle object from which the timezone data can be read. This does
not need to be a regular seekable file; it is read sequentially. After the
constructor has finished, the handle can still be used to read any data
that follows the timezone data.
Either a filename or filehandle must be given. If a timezone name
is not given, then the filename is used instead if supplied; a timezone name
must be given explicitly if no filename is given.
- DateTime::TimeZone::Tzfile->new(FILENAME)
- Simpler way to invoke the above constructor in the usual case. Only the
filename is given; this will also be used as the timezone name.
These methods are all part of the DateTime::TimeZone interface.
See that class for the general meaning of these methods; the documentation
below only comments on the specific behaviour of this class.
- $tz->is_floating
- Returns false.
- $tz->is_utc
- Returns false.
- $tz->is_olson
- Returns the truth value that was provided to the constructor for this
purpose, default false. This nominally indicates whether the timezone data
is from the Olson database. The files interpreted by this class are very
likely to be from the Olson database, but there is no explicit indicator
for this in the file, so this information must be supplied to the
constructor if required.
- $tz->category
- Returns the value that was provided to the constructor for this purpose,
default "undef". This is intended to
indicate the general region (continent or ocean) in which a geographical
timezone is used, when the timezone is named according to the hierarchical
scheme of the Olson timezone database.
- $tz->name
- Returns the timezone name. Usually this is the filename that was supplied
to the constructor, but it can be overridden by the constructor's
name attribute.
- $tz->has_dst_changes
- Returns a truth value indicating whether any of the observances in the
file are marked as DST. These DST flags are potentially arbitrary, and
don't affect any of the zone's behaviour.
- $tz->offset_for_datetime(DT)
- DT must be a DateTime-compatible object (specifically, it must
implement the "utc_rd_values" method).
Returns the offset from UT that is in effect at the instant represented by
DT, in seconds.
- $tz->is_dst_for_datetime(DT)
- DT must be a DateTime-compatible object (specifically, it must
implement the "utc_rd_values" method).
Returns a truth value indicating whether the timezone's observance at the
instant represented by DT is marked as DST. This DST flag is
potentially arbitrary, and doesn't affect anything else.
- $tz->short_name_for_datetime(DT)
- DT must be a DateTime-compatible object (specifically, it must
implement the "utc_rd_values" method).
Returns the abbreviation used to label the time scale at the instant
represented by DT. This abbreviation is potentially arbitrary, and
does not uniquely identify either the timezone or the offset.
- $tz->offset_for_local_datetime(DT)
- DT must be a DateTime-compatible object (specifically, it must
implement the "local_rd_values" method).
Takes the local time represented by DT (regardless of what absolute
time it also represents), and interprets that as a local time in the
timezone of the timezone object (not the timezone used in DT).
Returns the offset from UT that is in effect at that local time, in
seconds.
If the local time given is ambiguous due to a nearby offset
change, the numerically lowest offset (usually the standard one) is
returned with no warning of the situation. (Equivalently: the latest
possible absolute time is indicated.) If the local time given does not
exist due to a nearby offset change, the method
"die"s saying so.
DateTime, DateTime::TimeZone, DateTime::TimeZone::Olson,
Time::OlsonTZ::Data, Time::OlsonTZ::Download, tzfile(5)
Andrew Main (Zefram) <zefram@fysh.org>
Copyright (C) 2007, 2009, 2010, 2011, 2012, 2013, 2017 Andrew Main
(Zefram) <zefram@fysh.org>
This module is free software; you can redistribute it and/or
modify it under the same terms as Perl itself.