perl5122delta - what is new for perl v5.12.2


   This document describes differences between the 5.12.1 release and the
   5.12.2 release.

   If you are upgrading from an earlier major version, such as 5.10.1,
   first read perl5120delta, which describes differences between 5.10.1
   and 5.12.0, as well as perl5121delta, which describes earlier changes
   in the 5.12 stable release series.

Incompatible Changes

   There are no changes intentionally incompatible with 5.12.1. If any
   exist, they are bugs and reports are welcome.

Core Enhancements

   Other than the bug fixes listed below, there should be no user-visible
   changes to the core language in this release.

Modules and Pragmata

   New Modules and Pragmata
   This release does not introduce any new modules or pragmata.

   Pragmata Changes
   In the previous release, "no VERSION;" statements triggered a bug which
   could cause feature bundles to be loaded and strict mode to be enabled

   Updated Modules
       Upgraded from version 1.16 to 1.17.

       Carp now detects incomplete caller() overrides and avoids using
       bogus @DB::args. To provide backtraces, Carp relies on particular
       behaviour of the caller built-in. Carp now detects if other code
       has overridden this with an incomplete implementation, and modifies
       its backtrace accordingly. Previously incomplete overrides would
       cause incorrect values in backtraces (best case), or obscure fatal
       errors (worst case)

       This fixes certain cases of "Bizarre copy of ARRAY" caused by
       modules overriding "caller()" incorrectly.

       A patch to cpanp-run-perl has been backported from CPANPLUS 0.9004.
       This resolves RT #55964
       <> and RT #57106
       <>, both of
       which related to failures to install distributions that use

       A regression which caused a failure to find "CORE::GLOBAL::glob"
       after loading "File::Glob" to crash has been fixed.  Now, it
       correctly falls back to external globbing via "pp_glob".

       "File::Copy::copy(FILE, DIR)" is now documented.

       Upgraded from version 3.31 to 3.31_01.

       Several portability fixes were made in "File::Spec::VMS": a colon
       is now recognized as a delimiter in native filespecs; caret-escaped
       delimiters are recognized for better handling of extended
       filespecs; "catpath()" returns an empty directory rather than the
       current directory if the input directory name is empty; "abs2rel()"
       properly handles Unix-style input.

Utility Changes

   *   perlbug now always gives the reporter a chance to change the email
       address it guesses for them.

   *   perlbug should no longer warn about uninitialized values when using
       the "-d" and "-v" options.

Changes to Existing Documentation

   *   The existing policy on backward-compatibility and deprecation has
       been added to perlpolicy, along with definitions of terms like

   *   "srand" in perlfunc's usage has been clarified.

   *   The entry for "die" in perlfunc was reorganized to emphasize its
       role in the exception mechanism.

   *   Perl's INSTALL file has been clarified to explicitly state that
       Perl requires a C89 compliant ANSI C Compiler.

   *   IO::Socket's "getsockopt()" and "setsockopt()" have been

   *   alarm()'s inability to interrupt blocking IO on Windows has been

   *   Math::TrulyRandom hasn't been updated since 1996 and has been
       removed as a recommended solution for random number generation.

   *   perlrun has been updated to clarify the behaviour of octal flags to

   *   To ease user confusion, $# and $*, two special variables that were
       removed in earlier versions of Perl have been documented.

   *   The version of perlfaq shipped with the Perl core has been updated
       from the official FAQ version, which is now maintained in the
       "briandfoy/perlfaq" branch of the Perl repository at

Installation and Configuration Improvements

   Configuration improvements
   *   The "d_u32align" configuration probe on ARM has been fixed.

   Compilation improvements
   *   An ""incompatible operand types"" error in ternary expressions when
       building with "clang" has been fixed.

   *   Perl now skips setuid "File::Copy" tests on partitions it detects
       to be mounted as "nosuid".

Selected Bug Fixes

   *   A possible segfault in the "T_PRTOBJ" default typemap has been

   *   A possible memory leak when using caller() to set @DB::args has
       been fixed.

   *   Several memory leaks when loading XS modules were fixed.

   *   "unpack()" now handles scalar context correctly for %32H and %32u,
       fixing a potential crash.  "split()" would crash because the third
       item on the stack wasn't the regular expression it expected.
       "unpack("%2H", ...)" would return both the unpacked result and the
       checksum on the stack, as would "unpack("%2u", ...)".  [perl
       #73814] <>

   *   Perl now avoids using memory after calling "free()" in pp_require
       when there are CODEREFs in @INC.

   *   A bug that could cause ""Unknown error"" messages when
       ""call_sv(code, G_EVAL)"" is called from an XS destructor has been

   *   The implementation of the "open $fh, '>' \$buffer" feature now
       supports get/set magic and thus tied buffers correctly.

   *   The "pp_getc", "pp_tell", and "pp_eof" opcodes now make room on the
       stack for their return values in cases where no argument was passed

   *   When matching unicode strings under some conditions inappropriate
       backtracking would result in a "Malformed UTF-8 character (fatal)"
       error. This should no longer occur.  See  [perl #75680]

Platform Specific Notes

   *   README.aix has been updated with information about the XL C/C++ V11
       compiler suite.

   *   When building Perl with the mingw64 x64 cross-compiler "incpath",
       "libpth", "ldflags", "lddlflags" and "ldflags_nolargefiles" values
       in and were not previously being set
       correctly because, with that compiler, the include and lib
       directories are not immediately below "$(CCHOME)".

   *   git_version.h is now installed on VMS. This was an oversight in
       v5.12.0 which caused some extensions to fail to build.

   *   Several memory leaks in stat() have been fixed.

   *   A memory leak in "Perl_rename()" due to a double allocation has
       been fixed.

   *   A memory leak in "vms_fid_to_name()" (used by "realpath()" and
       "realname()") has been fixed.


   Perl 5.12.2 represents approximately three months of development since
   Perl 5.12.1 and contains approximately 2,000 lines of changes across
   100 files from 36 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 5.12.2:

   Abigail, var Arnfjr Bjarmason, Ben Morrow, brian d foy, Brian
   Phillips, Chas. Owens, Chris 'BinGOs' Williams, Chris Williams, Craig
   A. Berry, Curtis Jewell, Dan Dascalescu, David Golden, David Mitchell,
   Father Chrysostomos, Florian Ragwitz, George Greer, H.Merijn Brand, Jan
   Dubois, Jesse Vincent, Jim Cromie, Karl Williamson, Lars D
   , Leon Brocard, Maik Hentsche, Matt S Trout, Nicholas Clark,
   Rafael Garcia-Suarez, Rainer Tammer, Ricardo Signes, Salvador Ortiz
   Garcia, Sisyphus, Slaven Rezic, Steffen Mueller, Tony Cook, Vincent Pit
   and Yves Orton.

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.


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.