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Florian Ragwitz > perl-5.17.4 > perl5171delta


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Source   Latest Release: perl-5.17.11


perl5171delta - what is new for perl v5.17.1


This document describes differences between the 5.17.0 release and the 5.17.1 release.

If you are upgrading from an earlier release such as 5.16.0, first read perl5170delta, which describes differences between 5.16.0 and 5.17.0.

Core Enhancements ^

More CORE:: subs

Several more built-in functions have been added as subroutines to the CORE:: namespace, namely, those non-overridable keywords that can be implemented without custom parsers: defined, delete, exists, glob, pos, protoytpe, scalar, split, study, and undef.

As some of these have prototypes, prototype('CORE::...') has been changed to not make a distinction between overridable and non-overridable keywords. This is to make prototype('CORE::pos') consistent with prototype(&CORE::pos).

Incompatible Changes ^

/(?{})/ and /(??{})/ have been heavily reworked

The implementation of this feature has been almost completely rewritten. Although its main intent is to fix bugs, some behaviors, especially related to the scope of lexical variables, will have changed. This is described more fully in the "Selected Bug Fixes" section.

\N{BELL} now refers to U+1F514 instead of U+0007

Unicode 6.0 reused the name "BELL" for a different code point than it traditionally had meant. Since Perl v5.14, use of this name still referred to U+0007, but would raise a deprecation warning. Now, "BELL" refers to U+1F514, and the name for U+0007 is "ALERT". All the functions in charnames have been correspondingly updated.

Alphanumeric operators must now be separated from the closing delimiter of regular expressions

You may no longer write something like:

 m/a/and 1

Instead you must write

 m/a/ and 1

with whitespace separating the operator from the closing delimiter of the regular expression. Not having whitespace has resulted in a deprecation warning since Perl v5.14.0.

require dies for unreadable files

When require encounters an unreadable file, it now dies. It used to ignore the file and continue searching the directories in @INC [perl #113422].

Upgrade to the Unicode 6.2 beta

Unicode 6.2 is proposing some changes that may very well break some CPAN modules. The timing of this nicely coincides with Perl's being early in the release cycle. This commit takes the current beta 6.2, adds the proposed changes that aren't yet in it, and subtracts the changes that would affect \X processing, as those turn out to have errors, and may have to be rethought. Unicode has been notified of these problems.

This will allow us to gather data as to whether or not the proposed changes cause us problems. These will be presented to Unicode to aid in their final decision as to whether or not to go forward with the changes.

These changes will be replaced by the final version of Unicode 6.2 before 5.18.0 is released.

Performance Enhancements ^

Modules and Pragmata ^

Updated Modules and Pragmata

Documentation ^

Changes to Existing Documentation



Diagnostics ^

Removals of Diagnostics

Platform Support ^

Platform-Specific Notes


link on Win32 now attempts to set $! to more appropriate values based on the Win32 API error code. [perl #112272]

Perl no longer mangles the environment block, e.g. when launching a new sub-process, when the environment contains non-ASCII characters. Known problems still remain, however, when the environment contains characters outside of the current ANSI codepage (e.g. see the item about Unicode in %ENV in [perl #113536]


All C header files from the top-level directory of the distribution are now installed on VMS, providing consistency with a long-standing practice on other platforms. Previously only a subset were installed, which broke non-core extension builds for extensions that depended on the missing include files.

Internal Changes ^

Selected Bug Fixes ^

Known Problems ^

Acknowledgements ^

Perl 5.17.1 represents approximately 4 weeks of development since Perl 5.17.0 and contains approximately 37,000 lines of changes across 710 files from 35 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 5.17.1:

?, Andy Dougherty, Aristotle Pagaltzis, Breno G. de Oliveira, Brian Fraser, Chris 'BinGOs' Williams, Craig A. Berry, David Mitchell, Dominic Hargreaves, Evan Miller, Father Chrysostomos, Florian Ragwitz, H.Merijn Brand, Herbert Breunung, Hugo van der Sanden, Jesse Luehrs, Karl Williamson, Karthik Rajagopalan, Lukas Mai, Martin Hasch, Michael Schroeder, Nicholas Clark, Paul Johnson, Reini Urban, Renee Baecker, Rhesa Rozendaal, Ricardo Signes, Shlomi Fish, Steve Hay, Steve Peters, Sullivan Beck, Tony Cook, Volker Schatz, Yves Orton, Zefram.

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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