perl5121delta - what is new for perl v5.12.1


   This document describes differences between the 5.12.0 release and the
   5.12.1 release.

   If you are upgrading from an earlier release such as 5.10.1, first read
   perl5120delta, which describes differences between 5.10.1 and 5.12.0.

Incompatible Changes

   There are no changes intentionally incompatible with 5.12.0. If any
   incompatibilities with 5.12.0 exist, they are bugs. Please report them.

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

   Pragmata Changes
   *   We fixed exporting of "is_strict" and "is_lax" from version.

       These were being exported with a wrapper that treated them as
       method calls, which caused them to fail.  They are just functions,
       are documented as such, and should never be subclassed, so this
       patch just exports them directly as functions without the wrapper.

   Updated Modules
   *   We upgraded to version 3.49 to incorporate fixes for
       regressions introduced in the release we shipped with Perl 5.12.0.

   *   We upgraded Pod::Simple to version 3.14 to get an improvement to
       \C\<\< \>\> parsing.

   *   We made a small fix to the CPANPLUS test suite to fix an occasional
       spurious test failure.

   *   We upgraded Safe to version 2.27 to wrap coderefs returned by
       "reval()" and "rdo()".

Changes to Existing Documentation

   *   We added the new maintenance release policy to perlpolicy.pod

   *   We've clarified the multiple-angle-bracket construct in the spec
       for POD in perlpodspec

   *   We added a missing explanation for a warning about ":=" to

   *   We removed a false claim in perlunitut that all text strings are
       Unicode strings in Perl.

   *   We updated the Github mirror link in perlrepository to
       mirrors/perl, not github/perl

   *   We fixed a minor error in perl5114delta.pod.

   *   We replaced a mention of the now-obsolete with

   *   We improved documentation about $sitelibexp/ in

   *   We corrected perlmodlib.pod which had unintentionally omitted a
       number of modules.

   *   We updated the documentation for 'require' in perlfunc.pod relating
       to putting Perl code in @INC.

   *   We reinstated some erroneously-removed documentation about
       quotemeta in perlfunc.

   *   We fixed an a2p example in perlutil.pod.

   *   We filled in a blank in perlport.pod with the release date of Perl

   *   We fixed broken links in a number of perldelta files.

   *   The documentation for incorrectly stated that the
       $Carp::Verbose variable makes cluck generate stack backtraces.

   *   We fixed a number of typos in Pod::Functions

   *   We improved documentation of case-changing functions in

   *   We corrected perlgpl.pod to contain the correct version of the GNU
       General Public License.


   Testing Improvements
   *   t/op/sselect.t is now less prone to clock jitter during timing
       checks on Windows.

       sleep() time on Win32 may be rounded down to multiple of the clock
       tick interval.

   *   lib/blib.t and lib/locale.t: Fixes for test failures on Darwin/PPC

   *   perl5db.t: Fix for test failures when "Term::ReadLine::Gnu" is

Installation and Configuration Improvements

   Configuration improvements
   *   We updated INSTALL with notes about how to deal with broken dbm.h
       on OpenSUSE (and possibly other platforms)

Bug Fixes

   *   A bug in how we process filetest operations could cause a segfault.
       Filetests don't always expect an op on the stack, so we now use
       TOPs only if we're sure that we're not stat'ing the _ filehandle.
       This is indicated by OPf_KIDS (as checked in ck_ftst).

       See also: <>

   *   When deparsing a nextstate op that has both a change of package
       (relative to the previous nextstate) and a label, the package
       declaration is now emitted first, because it is syntactically
       impermissible for a label to prefix a package declaration.

   *   XSUB.h now correctly redefines fgets under PERL_IMPLICIT_SYS

       See also: <>

   *   utf8::is_utf8 now respects GMAGIC (e.g. $1)

   *   XS code using "fputc()" or "fputs()": on Windows could cause an
       error due to their arguments being swapped.

       See also: <>

   *   We fixed a small bug in lex_stuff_pvn() that caused spurious syntax
       errors in an obscure situation.  It happened when stuffing was
       performed on the last line of a file and the line ended with a
       statement that lacked a terminating semicolon.

       See also: <>

   *   We fixed a bug that could cause \N{} constructs followed by a
       single . to be parsed incorrectly.

       See also: <>

   *   We fixed a bug that caused when(scalar) without an argument not to
       be treated as a syntax error.

       See also: <>

   *   We fixed a regression in the handling of labels immediately before
       string evals that was introduced in Perl 5.12.0.

       See also: <>

   *   We fixed a regression in case-insensitive matching of folded
       characters in regular expressions introduced in Perl 5.10.1.

       See also: <>

Platform Specific Notes

   *   Perl now allows -Duse64bitint without promoting to use64bitall on

   *   Perl now builds on AIX 4.2

       The changes required work around AIX 4.2s' lack of support for
       IPv6, and limited support for POSIX "sigaction()".

   FreeBSD 7
   *   FreeBSD 7 no longer contains /usr/bin/objformat. At build time,
       Perl now skips the objformat check for versions 7 and higher and
       assumes ELF.

   *   It's now possible to build extensions on older (pre 7.3-2) VMS

       DCL symbol length was limited to 1K up until about seven years or
       so ago, but there was no particularly deep reason to prevent those
       older systems from configuring and building Perl.

   *   We fixed the previously-broken "-Uuseperlio" build on VMS.

       We were checking a variable that doesn't exist in the non-default
       case of disabling perlio.  Now we only look at it when it exists.

   *   We fixed the -Uuseperlio command-line option in

       Formerly it only worked if you went through all the questions
       interactively and explicitly answered no.

Known Problems

   *   "List::Util::first" misbehaves in the presence of a lexical $_
       (typically introduced by "my $_" or implicitly by "given"). The
       variable which gets set for each iteration is the package variable
       $_, not the lexical $_.

       A similar issue may occur in other modules that provide functions
       which take a block as their first argument, like

           foo { ... $_ ...} list

       See also: <>

   *   "Module::Load::Conditional" and "version" have an unfortunate
       interaction which can cause "CPANPLUS" to crash when it encounters
       an unparseable version string.  Upgrading to "CPANPLUS" 0.9004 or
       "Module::Load::Conditional" 0.38 from CPAN will resolve this issue.


   Perl 5.12.1 represents approximately four weeks of development since
   Perl 5.12.0 and contains approximately 4,000 lines of changes across
   142 files from 28 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 5.12.1:

   var Arnfjr Bjarmason, Chris Williams, chromatic, Craig A. Berry,
   David Golden, Father Chrysostomos, Florian Ragwitz, Frank Wiegand, Gene
   Sullivan, Goro Fuji, H.Merijn Brand, James E Keenan, Jan Dubois, Jesse
   Vincent, Josh ben Jore, Karl Williamson, Leon Brocard, Michael Schwern,
   Nga Tang Chan, Nicholas Clark, Niko Tyni, Philippe Bruhat, Rafael
   Garcia-Suarez, Ricardo Signes, Steffen Mueller, Todd Rinaldo, Vincent
   Pit and Zefram.

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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