my $tz = DateTime::TimeZone->new( name => 'local' ); my $tz = DateTime::TimeZone::Local->TimeZone();
It checks $ENV{TZ} for a valid time zone name.
If this file is a symlink to an Olson database time zone file (usually in /usr/share/zoneinfo) then it uses the target file's path name to determine the time zone name. For example, if the path is /usr/share/zoneinfo/America/Chicago, the time zone is ``America/Chicago''.
Some systems just copy the relevant file to /etc/localtime instead of making a symlink. In this case, we look in /usr/share/zoneinfo for a file that has the same size and content as /etc/localtime to determine the local time zone.
If this file exists, it is read and its contents are used as a time zone name.
If this file exists, it is opened and we look for a line starting like ``TZ = ...''. If this is found, it should indicate a time zone name.
If this file exists, it is opened and we look for a line starting like ``TIMEZONE = ...'' or ``ZONE = ...''. If this is found, it should indicate a time zone name.
If this file exists, it is opened and we look for a line starting like ``TZ=...''. If this is found, it should indicate a time zone name.
Note: Some systems such as virtual machine boxes may lack any of these files. You can confirm that this is case by running:
$ ls -l /etc/localtime /etc/timezone /etc/TIMEZONE \
/etc/sysconfig/clock /etc/default/init
If this is the case, then when checking for timezone handling you are likely to get an exception:
$ perl -wle 'use DateTime; DateTime->now( time_zone => "local" )'
Cannot determine local time zone
In that case, you should consult your system man pages for details on how to address that problem. In one such case reported to us, a FreeBSD virtual machine had been built without any of these files. The user was able to run the FreeBSD tzsetup utility. That installed /etc/localtime, after which the above timezone diagnostic ran silently, i.e., without throwing an exception.
This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.
The full text of the license can be found in the LICENSE file included with this distribution.