/ 
DateTime-TimeZone-Local-Win32-2.05
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/ DateTime::TimeZone::Local::Win32

NAME

DateTime::TimeZone::Local::Win32 - Determine the local system's time zone on Windows

VERSION

version 2.05

SYNOPSIS

  my $tz = DateTime::TimeZone->new( name => 'local' );

  my $tz = DateTime::TimeZone::Local->TimeZone();

DESCRIPTION

This module provides methods for determining the local time zone on a Windows platform.

NAME

DateTime::TimeZone::Local::Win32 - Determine the local system's time zone on Windows

HOW THE TIME ZONE IS DETERMINED

This class tries the following methods of determining the local time zone:

  • $ENV{TZ}

    It checks $ENV{TZ} for a valid time zone name.

  • Windows Registry

    When using the registry, we look for the Windows time zone and use a mapping to translate this to an IANA time zone name.

    • Windows Vista, 2008 Server and newer Windows operating systems

      We look in "SYSTEM/CurrentControlSet/Control/TimeZoneInformation/" for a node named "/TimeZoneKeyName". If this exists, we use this key to look up the IANA time zone name in our mapping.

    • Windows NT, Windows 2000, Windows XP, Windows 2003 Server

      We look in "SOFTWARE/Microsoft/Windows NT/CurrentVersion/Time Zones/" and loop through all of its sub keys.

      For each sub key, we compare the value of the key with "/Std" appended to the end to the value of "SYSTEM/CurrentControlSet/Control/TimeZoneInformation/StandardName". This gives us the English name of the Windows time zone, which we use to look up the IANA time zone name.

    • Windows 95, Windows 98, Windows Millenium Edition

      The algorithm is the same as for NT, but we loop through the sub keys of "SOFTWARE/Microsoft/Windows/CurrentVersion/Time Zones/"

AUTHORS

  • David Pinkowitz <dapink@cpan.org>

  • Dave Rolsky <autarch@urth.org>

COPYRIGHT AND LICENSE

Copyright (C) 2007-2014 Dave Rolsky <autarch@urth.org> Copyright (C) 2014-2021 by David Pinkowitz <dapink@cpan.org>

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.