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perl5203delta - what is new for perl v5.20.3


This document describes differences between the 5.20.2 release and the 5.20.3 release.

If you are upgrading from an earlier release such as 5.20.1, first read perl5202delta, which describes differences between 5.20.1 and 5.20.2.

Incompatible Changes

There are no changes intentionally incompatible with 5.20.2. If any exist, they are bugs, and we request that you submit a report. See "Reporting Bugs" below.

Modules and Pragmata

Updated Modules and Pragmata


Changes to Existing Documentation





Utility Changes



Platform Support

Platform-Specific Notes

  • Previously, when compiling with a 64-bit Visual C++, every Perl XS module (including CPAN ones) and Perl aware C file would unconditionally have around a dozen warnings from hv_func.h. These warnings have been silenced. GCC (all bitness) and 32-bit Visual C++ were not affected.

  • miniperl.exe is now built with -fno-strict-aliasing, allowing 64-bit builds to complete with GCC 4.8. [perl #123976]

Selected Bug Fixes


Perl 5.20.3 represents approximately 7 months of development since Perl 5.20.2 and contains approximately 3,200 lines of changes across 99 files from 26 authors.

Excluding auto-generated files, documentation and release tools, there were approximately 1,500 lines of changes to 43 .pm, .t, .c and .h files.

Perl continues to flourish into its third decade thanks to a vibrant community of users and developers. The following people are known to have contributed the improvements that became Perl 5.20.3:

Alex Vandiver, Andy Dougherty, Aristotle Pagaltzis, Chris 'BinGOs' Williams, Craig A. Berry, Dagfinn Ilmari Mannsåker, Daniel Dragan, David Mitchell, Father Chrysostomos, H.Merijn Brand, James E Keenan, James McCoy, Jarkko Hietaniemi, Karen Etheridge, Karl Williamson, kmx, Lajos Veres, Lukas Mai, Matthew Horsfall, Petr Písař, Randy Stauner, Ricardo Signes, Sawyer X, Steve Hay, Tony Cook, Yves Orton.

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 articles recently posted to the comp.lang.perl.misc newsgroup and the perl bug database at . There may also be information at , the Perl Home Page.

If you believe you have an unreported bug, please run the perlbug program included with your release. Be sure to trim your bug down to a tiny but sufficient test case. Your bug report, along with the output of perl -V, will be sent off to to be analysed by the Perl porting team.

If the bug you are reporting has security implications, which make it inappropriate to send to a publicly archived mailing list, then please send it to This points to a closed subscription unarchived mailing list, which includes all the core committers, who will be able to help assess the impact of issues, figure out a resolution, and help co-ordinate the release of patches to mitigate or fix the problem across all platforms on which Perl is supported. Please only use this address for security issues in the Perl core, not for modules independently distributed on CPAN.


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.