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PERL5212DELTA(1pm)     Perl Programmers Reference Guide     PERL5212DELTA(1pm)


       perl5212delta - what is new for perl v5.21.2


       This document describes differences between the 5.21.1 release and the
       5.21.2 release.

       If you are upgrading from an earlier release such as 5.21.0, first read
       perl5211delta, which describes differences between 5.21.0 and 5.21.1.

Core Enhancements

   Better heuristics on older platforms for determining locale UTF8ness
       On platforms that implement neither the C99 standard nor the POSIX 2001
       standard, determining if the current locale is UTF8 or not depends on
       heuristics.  These are improved in this release.


   Perl is now always compiled with -D_FORTIFY_SOURCE=2 if available
       The 'code hardening' option called "_FORTIFY_SOURCE", available in gcc
       4.*, is now always used for compiling Perl, if available.

       Note that this isn't necessarily a huge step since in many platforms
       the step had already been taken several years ago: many Linux
       distributions (like Fedora) have been using this option for Perl, and
       OS X has enforced the same for many years.


   "/\C/" character class
       This character class, which matches a single byte, even if it appears
       in a multi-byte character has been deprecated. Matching single bytes in
       a multi-byte character breaks encapsulation, and can corrupt utf8

Performance Enhancements

       o   Refactoring of "pp_tied" and C"pp_ref" for small improvements.

       o   Pathtools don't try to load XS on miniperl.

       o   A typo fix reduces the size of the "OP" structure.

       o   Hash lookups where the key is a constant is faster.

Modules and Pragmata

   Updated Modules and Pragmata
       o   arybase has been upgraded from version 0.07 to 0.08.

       o   B has been upgraded from version 1.49 to 1.50.

       o   Devel::Peek has been upgraded from version 1.17 to 1.18.

       o   experimental has been upgraded from version 0.007 to 0.008.

       o   ExtUtils::Manifest has been upgraded from version 1.63 to 1.64.

       o   File::Copy has been upgraded from version 2.29 to 2.30.

       o   The PathTools module collection (File::Spec and friends) has been
           upgraded from version 3.48 to 3.49.

       o   Filter::Simple has been upgraded from version 0.91 to 0.92.

       o   Hash::Util has been upgraded from version 0.17 to 0.18.

       o   IO has been upgraded from version 1.32 to 1.33.

       o   IO::Socket::IP has been upgraded from version 0.29 to 0.31.

           A better fix for subclassing "connect()".  [cpan #95983]
           <> [cpan #97050]

       o   IPC::Open3 has been upgraded from version 1.16 to 1.17.

       o   Math::BigInt has been upgraded from version 1.9995 to 1.9996.

           Correct handling of subclasses.  [cpan #96254]
           <> [cpan #96329]

       o   Module::CoreList has been upgraded from version 5.021001_01 to

       o   Pod::Usage has been upgraded from version 1.63 to 1.64.

       o   POSIX has been upgraded from version 1.40 to 1.41.

       o   threads has been upgraded from version 1.94 to 1.95.

       o   warnings has been upgraded from version 1.24 to 1.26.


   Changes to Existing Documentation

       o   We now have a code of conduct for the p5p mailing list, as
           documented in "STANDARDS OF CONDUCT" in perlpolicy.


       o   Improve documentation of "our".


       o   The empty conditional in "for" and "while" is now documented in


   New Diagnostics
       New Warnings

       o   Argument "%s" treated as 0 in increment (++)

           (W numeric) The indicated string was fed as an argument to the "++"
           operator which expects either a number or a string matching
           "/^[a-zA-Z]*[0-9]*\z/".  See "Auto-increment and Auto-decrement" in
           perlop for details.

       o   Redundant argument in %s

           (W redundant) You called a function with more arguments than other
           arguments you supplied indicated would be needed. Currently only
           emitted when a printf-type format required fewer arguments than
           were supplied, but might be used in the future for e.g. "pack" in

           The warnings category "redundant" is new. See also [RT #121025]

Configuration and Compilation

       o   A new compilation flag, "-DPERL_OP_PARENT" is available. For
           details, see the discussion below at "Internal Changes".


       o   "" now allows "plan skip_all => $reason", to make it more
           compatible with "Test::More".

Platform Support

   Platform-Specific Notes
           Builds on Solaris 10 with "-Dusedtrace" would fail early since make
           didn't follow implied dependencies to build "perldtrace.h".  Added
           an explicit dependency to "depend".  [perl #120120]

Internal Changes

       o   The following private API functions had their context parameter
           removed, "Perl_cast_ulong",  "Perl_cast_i32", "Perl_cast_iv",
           "Perl_cast_uv", "Perl_cv_const_sv", "Perl_mg_find",
           "Perl_mg_findext", "Perl_mg_magical", "Perl_mini_mktime",
           "Perl_my_dirfd", "Perl_sv_backoff", "Perl_utf8_hop".

           Users of the public API prefix-less calls remain unaffected.

       o   Experimental support for ops in the optree to be able to locate
           their parent, if any. A general-purpose function,
           "op_sibling_splice()" allows for general manipulating an
           "op_sibling" chain. The last op in such a chain is now marked with
           the field "op_lastsib".

           A new build define, "-DPERL_OP_PARENT" has been added; if given, it
           forces the core to use "op_lastsib" to detect the last sibling in a
           chain, freeing the last "op_sibling" pointer, which then points
           back to the parent (instead of being "NULL").

           A C-level "op_parent()" function, and a "B" "parent()" method have
           been added; under a default build, they return "NULL", but when
           "-DPERL_OP_PARENT" has been set, they return the parent of the
           current op.

Selected Bug Fixes

       o   "s///e" on tainted utf8 strings got "pos()" messed up. This bug,
           introduced in 5.20, is now fixed. [RT #122148]

       o   A non-word boundary in a regular expression ("\B") did not always
           match the end of the string; in particular "q{} =~ /\B/" did not
           match. This bug, introduced in perl 5.14, is now fixed. [RT

       o   "" P" =~ /(?=.*P)P/" should match, but did not. This is now fixed.
           [RT #122171].


       Perl 5.21.2 represents approximately 4 weeks of development since Perl
       5.21.1 and contains approximately 11,000 lines of changes across 220
       files from 27 authors.

       Excluding auto-generated files, documentation and release tools, there
       were approximately 5,700 lines of changes to 140 .pm, .t, .c and .h

       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 5.21.2:

       Aaron Crane, Abhijit Menon-Sen, Abigail, Alexandr Ciornii, brian d foy,
       Brian Fraser, Chris 'BinGOs' Williams, Craig A. Berry, Daniel Dragan,
       David Golden, David Mitchell, Dmitri Tikhonov, George Greer, H.Merijn
       Brand, James E Keenan, Jarkko Hietaniemi, Karen Etheridge, Karl
       Williamson, Matthew Horsfall, Peter John Acklam, Peter Martini, Reini
       Urban, Ricardo Signes, Steve Hay, Tony Cook, Yves Orton, AEvar
       Arnfjoer` Bjarmason.

       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.

perl v5.22.0                      2015-05-13                PERL5212DELTA(1pm)

perl 5.22 - Generated Fri Aug 14 15:17:19 CDT 2015
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