Data::ICal::Entry::TimUsereContributedData::ICal::Entry::TimeZone::Daylight(3)NAMEData::ICal::Entry::TimeZone::Daylight - Represents a Daylight Time base
offset from UTC for parent TimeZone
DESCRIPTION
A time zone is unambiguously defined by the set of time measurement
rules determined by the governing body for a given geographic area.
These rules describe at a minimum the base offset from UTC for the time
zone, often referred to as the Standard Time offset. Many locations
adjust their Standard Time forward or backward by one hour, in order to
accommodate seasonal changes in number of daylight hours, often
referred to as Daylight Saving Time. Some locations adjust their time
by a fraction of an hour. Standard Time is also known as Winter Time.
Daylight Saving Time is also known as Advanced Time, Summer Time, or
Legal Time in certain countries. The following table shows the changes
in time zone rules in effect for New York City starting from 1967. Each
line represents a description or rule for a particular observance.
Effective Observance Rule
Date (Date/Time) Offset Abbreviation
1967-* last Sun in Oct, 02:00 -0500 EST
1967-1973 last Sun in Apr, 02:00 -0400 EDT
1974-1974 Jan 6, 02:00 -0400 EDT
1975-1975 Feb 23, 02:00 -0400 EDT
1976-1986 last Sun in Apr, 02:00 -0400 EDT
1987-* first Sun in Apr, 02:00 -0400 EDT
Note: The specification of a global time zone registry is not addressed
by this document and is left for future study. However, implementers
may find the Olson time zone database [TZ] a useful reference. It is an
informal, public-domain collection of time zone information, which is
currently being maintained by volunteer Internet participants, and is
used in several operating systems. This database contains current and
historical time zone information for a wide variety of locations around
the globe; it provides a time zone identifier for every unique time
zone rule set in actual use since 1970, with historical data going back
to the introduction of standard time.
METHODS
ical_entry_type
Returns "DAYLIGHT", its iCalendar entry name.
mandatory_unique_properties
According to the iCalendar standard, the following properties must be
specified exactly one time in a daylight declaration:
dtstart tzoffsetto tzoffsetfrom
optional_repeatable_properties
According to the iCalendar standard, the following properties may be
specified any number of times for a daylight declaration:
comment rdate rrule tzname
AUTHOR
Jesse Vincent "<jesse@bestpractical.com>" with David Glasser, Simon
Wistow, and Alex Vandiver
LICENCE AND COPYRIGHT
Copyright (c) 2005 - 2009, Best Practical Solutions, LLC. All rights
reserved.
This module is free software; you can redistribute it and/or modify it
under the same terms as Perl itself. See perlartistic.
DISCLAIMER OF WARRANTY
BECAUSE THIS SOFTWARE IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY
FOR THE SOFTWARE, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT
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PARTIES PROVIDE THE SOFTWARE "AS IS" WITHOUT WARRANTY OF ANY KIND,
EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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perl v5.14.32009Data::ICal::Entry::TimeZone::Daylight(3)