perl5125delta - what is new for perl v5.12.5


   This document describes differences between the 5.12.4 release and the
   5.12.5 release.

   If you are upgrading from an earlier release such as 5.12.3, first read
   perl5124delta, which describes differences between 5.12.3 and 5.12.4.


   "Encode" decode_xs n-byte heap-overflow (CVE-2011-2939)
   A bug in "Encode" could, on certain inputs, cause the heap to overflow.
   This problem has been corrected.  Bug reported by Robert Zacek.

   "File::Glob::bsd_glob()" memory error with GLOB_ALTDIRFUNC (CVE-2011-2728).
   Calling "File::Glob::bsd_glob" with the unsupported flag
   GLOB_ALTDIRFUNC would cause an access violation / segfault.  A Perl
   program that accepts a flags value from an external source could expose
   itself to denial of service or arbitrary code execution attacks.  There
   are no known exploits in the wild.  The problem has been corrected by
   explicitly disabling all unsupported flags and setting unused function
   pointers to null.  Bug reported by Clment Lecigne.

   Heap buffer overrun in 'x' string repeat operator (CVE-2012-5195)
   Poorly written perl code that allows an attacker to specify the count
   to perl's 'x' string repeat operator can already cause a memory
   exhaustion denial-of-service attack. A flaw in versions of perl before
   5.15.5 can escalate that into a heap buffer overrun; coupled with
   versions of glibc before 2.16, it possibly allows the execution of
   arbitrary code.

   This problem has been fixed.

Incompatible Changes

   There are no changes intentionally incompatible with 5.12.4. If any
   exist, they are bugs and reports are welcome.

Modules and Pragmata

   Updated Modules

   B::Concise no longer produces mangled output with the -tree option
   [perl #80632].


   A regression introduced in Perl 5.8.8 has been fixed, that caused
   charnames::viacode(0) to return "undef" instead of the string "NULL"
   [perl #72624].

   Encode has been upgraded from version 2.39 to version 2.39_01.

   See "Security".

   File::Glob has been upgraded from version 1.07 to version 1.07_01.

   See "Security".


   The documentation for the "upper" function now actually says "upper",
   not "lower".


   Module::CoreList has been updated to version 2.50_02 to add data for
   this release.

Changes to Existing Documentation

   The perlebcdic document contains a helpful table to use in "tr///" to
   convert between EBCDIC and Latin1/ASCII.  Unfortunately, the table was
   the inverse of the one it describes.  This has been corrected.

   The section on User-Defined Case Mappings had some bad markup and
   unclear sentences, making parts of it unreadable.  This has been

   This document has been corrected to take non-ASCII platforms into

Installation and Configuration Improvements

   Platform Specific Changes
   Mac OS X
       There have been configuration and test fixes to make Perl build
       cleanly on Lion and Mountain Lion.

       The NetBSD hints file was corrected to be compatible with NetBSD

Selected Bug Fixes

   *   "chop" now correctly handles characters above "\x{7fffffff}" [perl

   *   "($<,$>) = (...)" stopped working properly in 5.12.0.  It is
       supposed to make a single "setreuid()" call, rather than calling
       "setruid()" and "seteuid()" separately.  Consequently it did not
       work properly.  This has been fixed [perl #75212].

   *   Fixed a regression of kill() when a match variable is used for the
       process ID to kill [perl #75812].

   *   "UNIVERSAL::VERSION" no longer leaks memory.  It started leaking in
       Perl 5.10.0.

   *   The C-level "my_strftime" functions no longer leaks memory.  This
       fixes a memory leak in "POSIX::strftime" [perl #73520].

   *   "caller" no longer leaks memory when called from the DB package if
       @DB::args was assigned to after the first call to "caller".  Carp
       was triggering this bug [perl #97010].

   *   Passing to "index" an offset beyond the end of the string when the
       string is encoded internally in UTF8 no longer causes panics [perl

   *   Syntax errors in "(?{...})" blocks in regular expressions no longer
       cause panic messages [perl #2353].

   *   Perl 5.10.0 introduced some faulty logic that made "U*" in the
       middle of a pack template equivalent to "U0" if the input string
       was empty.  This has been fixed [perl #90160].


   split() and @_
   split() no longer modifies @_ when called in scalar or void context.
   In void context it now produces a "Useless use of split" warning.  This
   is actually a change introduced in perl 5.12.0, but it was missed from
   that release's perl5120delta.


   Perl 5.12.5 represents approximately 17 months of development since
   Perl 5.12.4 and contains approximately 1,900 lines of changes across 64
   files from 18 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 5.12.5:

   Andy Dougherty, Chris 'BinGOs' Williams, Craig A. Berry, David
   Mitchell, Dominic Hargreaves, Father Chrysostomos, Florian Ragwitz,
   George Greer, Goro Fuji, Jesse Vincent, Karl Williamson, Leon Brocard,
   Nicholas Clark, Rafael Garcia-Suarez, Reini Urban, Ricardo Signes,
   Steve Hay, 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 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 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.


Personal Opportunity - Free software gives you access to billions of dollars of software at no cost. Use this software for your business, personal use or to develop a profitable skill. Access to source code provides access to a level of capabilities/information that companies protect though copyrights. Open source is a core component of the Internet and it is available to you. Leverage the billions of dollars in resources and capabilities to build a career, establish a business or change the world. The potential is endless for those who understand the opportunity.

Business Opportunity - Goldman Sachs, IBM and countless large corporations are leveraging open source to reduce costs, develop products and increase their bottom lines. Learn what these companies know about open source and how open source can give you the advantage.

Free Software

Free Software provides computer programs and capabilities at no cost but more importantly, it provides the freedom to run, edit, contribute to, and share the software. The importance of free software is a matter of access, not price. Software at no cost is a benefit but ownership rights to the software and source code is far more significant.

Free Office Software - The Libre Office suite provides top desktop productivity tools for free. This includes, a word processor, spreadsheet, presentation engine, drawing and flowcharting, database and math applications. Libre Office is available for Linux or Windows.

Free Books

The Free Books Library is a collection of thousands of the most popular public domain books in an online readable format. The collection includes great classical literature and more recent works where the U.S. copyright has expired. These books are yours to read and use without restrictions.

Source Code - Want to change a program or know how it works? Open Source provides the source code for its programs so that anyone can use, modify or learn how to write those programs themselves. Visit the GNU source code repositories to download the source.


Study at Harvard, Stanford or MIT - Open edX provides free online courses from Harvard, MIT, Columbia, UC Berkeley and other top Universities. Hundreds of courses for almost all major subjects and course levels. Open edx also offers some paid courses and selected certifications.

Linux Manual Pages - A man or manual page is a form of software documentation found on Linux/Unix operating systems. Topics covered include computer programs (including library and system calls), formal standards and conventions, and even abstract concepts.