You are viewing the version of this documentation from Perl 5.33.6. This is a development release of Perl.



perldelta - what is new for perl v5.33.6


This document describes differences between the 5.33.5 release and the 5.33.6 release.

If you are upgrading from an earlier release such as 5.33.4, first read perl5335delta, which describes differences between 5.33.4 and 5.33.5.

Core Enhancements

qr/{,n}/ is now accepted

An empty lower bound is now accepted for regular expression quantifiers, like {,3}.

Blanks freely allowed within but adjacent to curly braces

(in double-quotish contexts and regular expression patterns)

This means you can write things like \x{ FFFC } if you like. This applies to all such constructs, namely \b{}, \g{}, \k{}, \N{}, \o{}, and \x{}; as well as the regular expression quantifier {m,n}. \p{} and \P{} retain their already-existing, even looser, rules mandated by the Unicode standard (see "Properties accessible through \p{} and \P{}" in perluniprops).

This ability is in effect regardless of the presence of the /x regular expression pattern modifier.

Additionally, the comma in a regular expression braced quantifier may have blanks (tabs or spaces) before and/or after the comma, like qr/a{ 5, 7 }/.

Modules and Pragmata

Updated Modules and Pragmata


New Documentation


This document describes the goals, scope, system, and rules for Perl's new governance model.

Other pod files, most notably perlpolicy, were amended to reflect its adoption.

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

Additionally, the following selected changes have been made:





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 perldiag.

New Diagnostics

New Errors

Changes to Existing Diagnostics

Configuration and Compilation


Tests were added and changed to reflect the other additions and changes in this release. Furthermore, these significant changes were made:

Platform Support

Platform-Specific Notes

Mac OS X

A number of system libraries no longer exist as actual files on Big Sur, even though dlopen will pretend they do, so now we fall back to dlopen if a library file can not be found. [GH #18407]

MS Windows

perl can now be built with USE_QUADMATH on MS Windows using (32-bit and 64-bit) mingw-w64 ports of gcc. [GH #18465]

The utility now needs to use ExtUtils::PL2Bat. This could cause failures in parallel builds.

Selected Bug Fixes


Perl 5.33.6 represents approximately 4 weeks of development since Perl 5.33.5 and contains approximately 96,000 lines of changes across 450 files from 26 authors.

Excluding auto-generated files, documentation and release tools, there were approximately 85,000 lines of changes to 320 .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 5.33.6:

Branislav Zahradník, Chris 'BinGOs' Williams, Craig A. Berry, Dan Book, Daniel Böhmer, Daniel Laügt, Felipe Gasper, Hugo van der Sanden, James E Keenan, Kang-min Liu, Karen Etheridge, Karl Williamson, Leon Timmermans, Max Maischein, Michael G Schwern, Paul Evans, Ricardo Signes, Richard Leach, Sawyer X, Sergey Poznyakoff, Sisyphus, Steve Hay, TAKAI Kousuke, Tomasz Konojacki, Tom Hukins, Tony Cook.

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 AUTHORS file in the Perl source distribution.

Reporting Bugs

If you find what you think is a bug, you might check the perl bug database at There may also be information at, the Perl Home Page.

If you believe you have an unreported bug, please open an issue at 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 "SECURITY VULNERABILITY CONTACT INFORMATION" in perlsec for details of how to report the issue.

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 perlthanks program:


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


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

The INSTALL file for how to build Perl.

The README file for general stuff.

The Artistic and Copying files for copyright information.