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Source   Latest Release: perl-5.19.10


perl5194delta - what is new for perl v5.19.4


This document describes differences between the 5.19.3 release and the 5.19.4 release.

If you are upgrading from an earlier release such as 5.19.2, first read perl5193delta, which describes differences between 5.19.2 and 5.19.3.

Core Enhancements ^

rand now uses a consistent random number generator

Previously perl would use a platform specific random number generator, varying between the libc rand(), random() or drand48().

This meant that the quality of perl's random numbers would vary from platform to platform, from the 15 bits of rand() on Windows to 48-bits on POSIX platforms such as Linux with drand48().

Perl now uses its own internal drand48() implementation on all platforms. This does not make perl's rand cryptographically secure. [perl #115928]

Better 64-bit support

On 64-bit platforms, the internal array functions now use 64-bit offsets, allowing Perl arrays to hold more than 2**31 elements, if you have the memory available.

The regular expression engine now supports strings longer than 2**31 characters. [perl #112790, #116907]

The functions PerlIO_get_bufsiz, PerlIO_get_cnt, PerlIO_set_cnt and PerlIO_set_ptrcnt now have SSize_t, rather than int, return values and parameters.

New slice syntax

The new %hash{...} and %array[...] syntax returns a list of key/value (or index/value) pairs. See "Key/Value Hash Slices" in perldata.

EBCDIC support

Core Perl now mostly works on EBCDIC platforms. This is not true of many modules, including some which are shipped with this release. If you have resources to help continue this process, including test machines, send email to

As a result of this, certain XS functions are now deprecated; see "Internal Changes".

Incompatible Changes ^

Locale decimal point character no longer leaks outside of use locale scope (with the exception of $!)

This is actually a bug fix, but some code has come to rely on the bug being present, so this change is listed here. The current locale that the program is running under is not supposed to be visible to Perl code except within the scope of a use locale. However, until now under certain circumstances, the character used for a decimal point (often a comma) leaked outside the scope.

This continues the work released in Perl 5.19.1. It turns out that that did not catch all the leaks, including printf and sprintf not respecting use locale. If your code is affected by this change, simply add a use locale.

Now, the only known place where use locale is not respected is in the stringification of $!.

Assignments of Windows sockets error codes to $! now prefer errno.h values over WSAGetLastError() values

In previous versions of Perl, Windows sockets error codes as returned by WSAGetLastError() were assigned to $!, and some constants such as ECONNABORTED, not in errno.h in VC++ (or the various Windows ports of gcc) were defined to corresponding WSAE* values to allow $! to be tested against the E* constants exported by Errno and POSIX.

This worked well until VC++ 2010 and later, which introduced new E* constants with values > 100 into errno.h, including some being (re)defined by perl to WSAE* values. That caused problems when linking XS code against other libraries which used the original definitions of errno.h constants.

To avoid this incompatibility, perl now maps WSAE* error codes to E* values where possible, and assigns those values to $!. The E* constants exported by Errno and POSIX are updated to match so that testing $! against them, wherever previously possible, will continue to work as expected, and all E* constants found in errno.h are now exported from those modules with their original errno.h values

In order to avoid breakage in existing Perl code which assigns WSAE* values to $!, perl now intercepts the assignment and performs the same mapping to E* values as it uses internally when assigning to $! itself.

However, one backwards-incompatibility remains: existing Perl code which compares $! against the numeric values of the WSAE* error codes that were previously assigned to $! will now be broken in those cases where a corresponding E* value has been assigned instead. This is only an issue for those E* values < 100, which were always exported from Errno and POSIX with their original errno.h values, and therefore could not be used for WSAE* error code tests (e.g. WSAEINVAL is 10022, but the corresponding EINVAL is 22). (E* values > 100, if present, were redefined to WSAE* values anyway, so compatibility can be achieved by using the E* constants, which will work both before and after this change, albeit using different numeric values under the hood.)

Deprecations ^

Literal control characters in variable names

This deprecation affects things like $\cT, where \cT is a literal control in the source code. Surprisingly, it appears that originally this was intended as the canonical way of accessing variables like $^T, with the caret form only being added as an alternative.

The literal control form is being deprecated for two main reasons. It has what are likely unfixable bugs, such as $\cI not working as an alias for $^I, and their usage not being portable to non-ASCII platforms: While $^T will work everywhere, \cT is whitespace in EBCDIC. [perl #119123]

Performance Enhancements ^

Modules and Pragmata ^

Updated Modules and Pragmata

Documentation ^

New Documentation


This document was removed (actually, renamed perlgit and given a major overhaul) in Perl 5.13.10, causing Perl documentation websites to show the now out of date version in Perl 5.12 as the latest version. It has now been restored in stub form, directing readers to current information.

Changes to Existing Documentation






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 Errors

New Warnings

Changes to Existing Diagnostics

Utility Changes ^


Configuration and Compilation ^

Testing ^

Platform Support ^

New Platforms


Support has been added for FreeMiNT, a free open-source OS for the Atari ST system and its successors, based on the original MiNT that was officially adopted by Atari.


Compile support has been added for Bitrig, a fork of OpenBSD.

Discontinued Platforms

Configure hints and conditional code for several very old platforms has been removed. We have not received reports for these in many years, typically not since Perl 5.6.0.

AT&T 3b1

Configure support for the 3b1, also known as the AT&T Unix PC (and the similar AT&T 7300), has been removed.

Platform-Specific Notes


The PERL_ENV_TABLES feature to control the population of %ENV at perl start-up was broken in Perl 5.16.0 but has now been fixed.


rename and link on Win32 now set $! to ENOSPC and EDQUOT when appropriate. [perl #119857]


Perl now builds again on WinCE, following locale-related breakage (WinCE has non-existent locale support) introduced around 5.19.1. [perl #119443]

The building of XS modules has largely been restored. Several still cannot (yet) be built but it is now possible to build Perl on WinCE with only a couple of further patches (to Socket and ExtUtils::MakeMaker), hopefully to be incorporated soon.


The BSD compatibility library libbsd is no longer required for builds.

Internal Changes ^

Selected Bug Fixes ^

Acknowledgements ^

Perl 5.19.4 represents approximately 4 weeks of development since Perl 5.19.3 and contains approximately 31,000 lines of changes across 580 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 5.19.4:

Andy Dougherty, Brian Fraser, Chris 'BinGOs' Williams, Christian Millour, Craig A. Berry, Daniel Dragan, David Golden, David Leadbeater, David Mitchell, Father Chrysostomos, Florian Ragwitz, François Perrad, H.Merijn Brand, James E Keenan, John Goodyear, John P. Linderman, John Peacock, Karl Williamson, kevin dawson, Leon Timmermans, Marco Peereboom, Matthew Horsfall, Nathan Glenn, Neil Bowers, Nicholas Clark, Niels Thykier, Niko Tyni, Owain G. Ainsworth, Peter John Acklam, Reini Urban, Ricardo Signes, Ruslan Zakirov, Slaven Rezic, Smylers, Steve Hay, Sullivan Beck, Toby Inkster, Tokuhiro Matsuno, Tony Cook, Victor Efimov, Zefram, Zsbán Ambrus.

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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