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Max Maischein > perl-5.17.10 > perldelta


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Source   Latest Release: perl-5.28.0-RC4


perldelta - what is new for perl v5.17.10


This document describes differences between the 5.17.9 release and the 5.17.10 release.

If you are upgrading from an earlier release such as 5.17.8, first read perl5179delta, which describes differences between 5.17.8 and 5.17.9.

Security ^

Hash iteration randomized per hash variable

Every hash has its own iteration order, which should make it much more difficult to determine what the current hash seed is.

Incompatible Changes ^

Explicit rules for variable names and identifiers

Due to an oversight, length-one variable names in 5.16 were completely unrestricted, and opened the door to several kinds of insanity. As of 5.18, these now follow the rules of other identifiers, in addition to accepting characters that match the \p{POSIX_Punct} property.

There are no longer any differences in the parsing of identifiers specified as $... or ${...}; previously, they were dealt with in different parts of the core, and so had slightly different behavior. For instance, ${foo:bar} was a legal variable name. Since they are now both parsed by the same code, that is no longer the case.

[ List each incompatible change as a =head2 entry ]

Deprecations ^


This interpreter-global variable used to track the total number of Perl objects in the interpreter. It is no longer maintained and will be removed altogether in Perl 5.20.

Modules and Pragmata ^

New Modules and Pragmata

Updated Modules and Pragmata

Documentation ^

Changes to Existing Documentation

"\N" in perlrebackslash

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 perldiag.

New Diagnostics

New Warnings

Changes to Existing Diagnostics

Internal Changes ^

Selected Bug Fixes ^

Acknowledgements ^

Perl 5.17.10 represents approximately 4 weeks of development since Perl 5.17.9 and contains approximately 77,000 lines of changes across 440 files from 42 authors.

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 5.17.10:

Aaron Crane, Aaron Trevena, Andrew Tam, Andy Dougherty, Anton Nikishaev, Brad Gilbert, Brian Fraser, Charlie Gonzalez, Chris 'BinGOs' Williams, Craig A. Berry, Daniel Dragan, David Golden, David Mitchell, Dominic Hargreaves, Florian Ragwitz, George Greer, H.Merijn Brand, James E Keenan, Jasmine Ahuja, John Goodyear, John Peacock, Karl Williamson, Kent Fredric, Lukas Mai, Max Maischein, Nicholas Clark, Patrik Hägglund, Paul Green, Peter Martini, Rafael Garcia-Suarez, Renee Baecker, Ricardo Signes, Ruslan Zakirov, Salvador Fandiño, Scott Lanning, Shirakata Kentaro, Steffen Müller, Steve Hay, Steve Peters, Sullivan Beck, 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.

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