# Copyright (c) 2009-2021 Sullivan Beck. All rights reserved.
# This program is free software; you can redistribute it and/or modify it
# under the same terms as Perl itself.

=pod

=head1 NAME

Date::Manip::Migration5to6 - how to upgrade from 5.xx to 6.00

=head1 SYNOPSIS

When upgrading from Date::Manip 5.xx to 6.00, a few changes may be
necessary to your scripts.

The L<Date::Manip::Changes5to6> document lists in more detail the ways in
which Date::Manip changed, but very few of these actually entail
changes to your script.

It should be noted that once the changes are made to your script,
it will no longer run correctly in 5.xx.

=head1 NECESSARY AND SUGGESTED CHANGES

The following changes are necessary, or strongly suggested:

=over 4

=item B<Reading config files with Date_Init>

If you use Date_Init to read any config files (if you do business mode
calculations, you probably do), you should remove all of the following
config variables from your call to Date_Init:

   GlobalCnf=FILE
   PersonalCnf=FILE
   PathSep=*
   IgnoreGlobalCnf=*
   PersonalCnfPath=*

and replace them with:

   ConfigFile=FILE

where FILE is now the full path to a config file. Also, the ConfigFile
argument should be the first argument in Date_Init.

=item B<Date_ConvTZ>

The Date_ConvTZ function has changed. It should now take 3 arguments:

   $date = Date_ConvTZ($date,$from,$to);

If C<$from> is not given, it defaults to the local time zone. If C<$to> is
not given, it defaults to the local time zone.

The date is converted from the C<$from> time zone into the C<$to>
time zone. Both should be any time zone (or alias) supported by
Date::Manip.

The old C<$errlevel> argument is no longer handled.

=item B<ConvTZ and TZ config variables>

If you use either the ConvTZ or TZ config variables, you should
replace them with either SetDate or ForceDate. See the
L<Date::Manip::Config> document for information.

The TZ variable will continue to work until Dec 2015 at which point
it will be removed.

=item B<Other deprecated config variables>

The following config variables have been deprecated, but will continue
to function (though they will be removed at a future date):

   TZ           (removed Mar 2016)

The following variables have been removed. If you use any of them,
you may need to modify your scripts:

   IntCharSet
   GlobalCnf
   PersonalCnf
   PathSep
   IgnoreGlobalCnf
   PersonalCnfPath
   ConvTZ
   Internal
   TodayIsMidnight
   DeltaSigns
   UpdateCurrTZ
   ResetWorkdDay

=item B<today, yesterday, tomorrow>

If you parse the strings "today", "yesterday", or "tomorrow" in order
to get the time now, or 24 hours in the past/future, this will no
longer work.  These strings now refer strictly to the date (so "today"
is the current day at midnight, "yesterday" is the previous day at
midnight, etc.).

To get the time now, 24 hours ago, or 24 hours in the future, you
would need to parse the strings "now", "-24:00:00", or "+24:00:00"
respectively.

=item B<Do not use Memoize>

In 5.xx, it was documented that you could use the module Memoize to
speed up Date::Manip, especially when sorting dates.

This information is no longer accurate. Using Memoize in conjunction
with Date::Manip should have little impact on performance, and may
lead to incorrect results, especially if you change config variables.

Please refer to L<Date::Manip::Changes5to6/"GENERAL CHANGES"> for
more information.

=back

If you find other instances where it is necessary to modify your
script, please email me so that I can add that information to this
document.

=head1 BUGS AND QUESTIONS

Please refer to the L<Date::Manip::Problems> documentation for
information on submitting bug reports or questions to the author.

=head1 SEE ALSO

L<Date::Manip>        - main module documentation

=head1 LICENSE

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

=head1 AUTHOR

Sullivan Beck (sbeck@cpan.org)

=cut
