=encoding utf8

=head1 NAME

perl5331delta - what is new for perl v5.33.1

=head1 DESCRIPTION

This document describes differences between the 5.33.0 release and the 5.33.1
release.

If you are upgrading from an earlier release such as 5.32.0, first read
L<perl5330delta>, which describes differences between 5.32.0 and 5.33.0.

=head1 Modules and Pragmata

=head2 New Modules and Pragmata

=over 4

=item *

L<ExtUtils::PL2Bat> 0.002 has been added to the Perl core.

This module is a generalization of the C<pl2bat> script. It being a script has led
to at least two forks of this code, this modules will unify them under one
implementation with tests.

=back

=head2 Updated Modules and Pragmata

=over 4

=item *

L<B> has been upgraded from version 1.80 to 1.81.

=item *

L<B::Deparse> has been upgraded from version 1.54 to 1.55.

=item *

L<Data::Dumper> has been upgraded from version 2.174 to 2.175.

=item *

L<Devel::Peek> has been upgraded from version 1.28 to 1.29.

=item *

L<Devel::PPPort> has been upgraded from version 3.57 to 3.60.

New C<PERL_VERSION_*> comparison macros are now available.

C<ppport.h --api-info> no longer includes non-API info unless that is the only match

=item *

L<DynaLoader> has been upgraded from version 1.47 to 1.48.

=item *

L<Errno> has been upgraded from version 1.30 to 1.31.

=item *

L<Exporter> has been upgraded from version 5.74 to 5.75.

=item *

L<ExtUtils::Miniperl> has been upgraded from version 1.09 to 1.10.

=item *

L<ExtUtils::ParseXS> has been upgraded from version 3.40 to 3.41.

=item *

L<Fcntl> has been upgraded from version 1.13 to 1.14.

=item *

L<feature> has been upgraded from version 1.59 to 1.60.

A new L<multidimensional|feature/"The 'multidimensional' feature">
feature has been added, which is enabled by
default but allows turning off L<multi-dimensional array
emulation|perldata/Multi-dimensional array emulation>.

=item *

L<File::Path> has been upgraded from version 2.16 to 2.17.

=item *

L<Hash::Util> has been upgraded from version 0.23 to 0.24.

=item *

L<Hash::Util::FieldHash> has been upgraded from version 1.20 to 1.21.

=item *

L<IO> has been upgraded from version 1.43 to 1.44.

The C<error> method now reports the error state for both the input and
output streams for sockets and character devices.  Similarly
C<clearerr> now clears the error state for both streams.

A spurious error reported for regular file handles has been
fixed in L<IO::Handle>.  L<GH #18019|https://github.com/Perl/perl5/issues/18019>

=item *

L<IPC::SysV> has been upgraded from version 2.07 to 2.08.

=item *

L<JSON::PP> has been upgraded from version 4.04 to 4.05.

=item *

L<Math::Complex> has been upgraded from version 1.5901 to 1.5902.

=item *

L<Module::CoreList> has been upgraded from version 5.20200717 to 5.20200820.

=item *

L<mro> has been upgraded from version 1.23 to 1.24.

=item *

L<Net::Ping> has been upgraded from version 2.72 to 2.73_01.

=item *

L<PerlIO::mmap> has been upgraded from version 0.016 to 0.017.

=item *

L<Pod::Usage> has been upgraded from version 1.69 to 1.70.

=item *

L<POSIX> has been upgraded from version 1.94 to 1.95.

=item *

L<Safe> has been upgraded from version 2.41 to 2.42.

=item *

L<Socket> has been upgraded from version 2.029 to 2.030.

=item *

L<Storable> has been upgraded from version 3.21 to 3.22.

=item *

L<strict> has been upgraded from version 1.11 to 1.12.

=item *

L<threads> has been upgraded from version 2.25 to 2.26.

=item *

L<threads::shared> has been upgraded from version 1.61 to 1.62.

=item *

L<Time::HiRes> has been upgraded from version 1.9764 to 1.9765.

=item *

L<Unicode::Normalize> has been upgraded from version 1.27 to 1.28.

=item *

L<warnings> has been upgraded from version 1.47 to 1.48.

=item *

L<XS::APItest> has been upgraded from version 1.09 to 1.11.

=item *

L<XS::Typemap> has been upgraded from version 0.17 to 0.18.

=back

=head1 Documentation

=head2 Changes to Existing Documentation

We have attempted to update the documentation to reflect the changes
listed in this document.  If you find any we have missed, open an issue
at L<https://github.com/Perl/perl5/issues>.

Additionally, the following selected changes have been made:

=head3 L<perldebguts>

=over 4

=item *

Corrected the description of the scalar C<< ${"_<$filename"} >>
variables.

=back

=head3 L<perlfunc>

=over 4

=item *

Better explanation of what happens when C<sleep> is called with a zero or
negative value.

=back

=head3 L<perlguts>

=over 4

=item *

Corrected C<my_rpeep> example in perlguts.

=item *

A section has been added on the formatted printing of special sizes.

=back

=head3 L<perlop>

=over 4

=item *

The C<< <> >> and C<<< <<>> >>> operators are commonly referred to as
the diamond and double diamond operators respectively, but that wasn't
mentioned previously in their documentation.

=item *

Document range op behavior change.

=back

=head3 L<perlpacktut>

=over 4

=item *

Incorrect variables used in an example have been fixed.

=back

=head1 Diagnostics

The following additions or changes have been made to diagnostic output,
including warnings and fatal error messages.  For the complete list of
diagnostic messages, see L<perldiag>.

=head2 New Diagnostics

=head3 New Errors

=over 4

=item *

L<Multidimensional hash lookup is disabled|perldiag/"Multidimensional hash lookup is disabled">

This accompanies the new L<multidimensional|feature/"The 'multidimensional' feature"> feature.

=back

=head2 Changes to Existing Diagnostics

=over 4

=item *

L<Use of uninitialized value%s|perldiag/"Use of uninitialized value%s">

This warning may now include the array or hash index when the
uninitialized value is the result of an element not found.  This will
only happen if the index is a simple non-magical variable.

=back

=head1 Utility Changes

=head2 L<perl5db.pl> (the debugger)

=over 4

=item * New option: C<HistItemMinLength>

This option controls the minimum length a command must be to get stored in
history.  Traditionally, this has been fixed at 2.  Changes to the debugger
are often perilous, and new bugs should be reported so the debugger can be
debugged.

=item * Fix to C<i> and C<l> commands

The C<i $var> and C<l $var> commands work again with lexical variables.

=back

=head1 Configuration and Compilation

=over 4

=item *

The minimum supported Bison version is now 2.4, and the maxiumm is 3.7.

=item *

Newer 64-bit versions of the Intel C/C++ compiler are now recognised
and have the correct flags set.

=back

=head1 Testing

Tests were added and changed to reflect the other additions and changes
in this release.

=head1 Platform Support

=head2 New Platforms

=over 4

=item 9front

Allow building Perl on i386 9front systems (fork of plan9).

=back

=head2 Updated Platforms

=over 4

=item Plan9

Improve support for Plan9 on i386 platforms.

=item MacOS (Darwin)

The hints file for darwin has been updated to handle future MacOS versions
beyond 10. L<GH #17946|https://github.com/Perl/perl5/issues/17946>

=back

=head2 Discontinued Platforms

=over 4

=item Symbian

Support code relating to Symbian has been removed.  Symbian was an
operating system for mobile devices.  The port was last updated in July
2009, and the platform itself in October 2012.

=back

=head2 Platform-Specific Notes

=over 4

=item z/OS

The locale categories C<LC_SYNTAX> and C<LC_TOD> are now recognized.
Perl doesn't do anything with these, except it now allows you to specify
them.  They are included in C<LC_ALL>.

=back

=head1 Internal Changes

=over 4

=item *

The C<PERL_GLOBAL_STRUCT> compilation option has been removed, and
with it the need or the C<dVAR> macro.  C<dVAR> remains defined as a
no-op outside C<PERL_CORE> for backwards compatiblity with XS modules.

=item *

A new savestack type C<SAVEt_HINTS_HH> has been added, which neatens the
previous behaviour of C<SAVEt_HINTS>.  On previous versions the types and
values pushed to the save stack would depend on whether the hints included the
C<HINT_LOCALIZE_HH> bit, which complicates external code that inspects the
save stack. The new version uses a different savestack type to indicate the
difference.

=item *

A new API function L<perlapi/av_count> has been added which gives a
clearly named way to find how many elements are in an array.

=back

=head1 Selected Bug Fixes

=over 4

=item *

On Win32, C<waitpid(-1, WNOHANG)> could sometimes have a very large
timeout.  L<GH #16529|https://github.com/Perl/perl5/issues/16529>

=item *

C<MARK> and hence C<items> are now correctly initialized in BOOT XSUBs.

=item *

Some list assignments involving C<undef> on the left-hand side were
over-optimized and produced incorrect results. L<GH #16685|https://github.com/Perl/perl5/issues/16685>, L<GH #17816|https://github.com/Perl/perl5/issues/17816>

=back

=head1 Acknowledgements

Perl 5.33.1 represents approximately 5 weeks of development since Perl
5.33.0 and contains approximately 37,000 lines of changes across 740 files
from 34 authors.

Excluding auto-generated files, documentation and release tools, there were
approximately 11,000 lines of changes to 290 .pm, .t, .c and .h files.

Perl continues to flourish into its fourth decade thanks to a vibrant
community of users and developers. The following people are known to have
contributed the improvements that became Perl 5.33.1:

Adam Hartley, Christian Walde (Mithaldu), Dagfinn Ilmari Mannsåker, Dan
Book, David Mitchell, E. Choroba, Graham Knop, Graham Ollis, Hauke D, Ivan
Baidakou, James E Keenan, John Lightsey, Karen Etheridge, Karl Williamson,
Leon Timmermans, Nicolas R., Paul Evans, Petr Písař, raiph, Renee Baecker,
Ricardo Signes, Richard Leach, Romano, Ryan Voots, Samuel Thibault, Sawyer
X, Scott Baker, Sizhe Zhao, Thibault Duponchelle, Todd Rinaldo, Tomasz
Konojacki, Tom Stellard, Tony Cook, vividsnow.

The list above is almost certainly incomplete as it is automatically
generated from version control history. In particular, it does not include
the names of the (very much appreciated) contributors who reported issues to
the Perl bug tracker.

Many of the changes included in this version originated in the CPAN modules
included in Perl's core. We're grateful to the entire CPAN community for
helping Perl to flourish.

For a more complete list of all of Perl's historical contributors, please
see the F<AUTHORS> file in the Perl source distribution.

=head1 Reporting Bugs

If you find what you think is a bug, you might check the perl bug database
at L<https://github.com/Perl/perl5/issues>.  There may also be information at
L<http://www.perl.org/>, the Perl Home Page.

If you believe you have an unreported bug, please open an issue at
L<https://github.com/Perl/perl5/issues>.  Be sure to trim your bug down to a
tiny but sufficient test case.

If the bug you are reporting has security implications which make it
inappropriate to send to a public issue tracker, then see
L<perlsec/SECURITY VULNERABILITY CONTACT INFORMATION>
for details of how to report the issue.

=head1 Give Thanks

If you wish to thank the Perl 5 Porters for the work we had done in Perl 5,
you can do so by running the C<perlthanks> program:

    perlthanks

This will send an email to the Perl 5 Porters list with your show of thanks.

=head1 SEE ALSO

The F<Changes> file for an explanation of how to view exhaustive details on
what changed.

The F<INSTALL> file for how to build Perl.

The F<README> file for general stuff.

The F<Artistic> and F<Copying> files for copyright information.

=cut
