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       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

   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

       ·   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

       ·   We added a missing explanation for a warning about ":=" to perldiag.pod

       ·   We removed a false claim in perlunitut that all text strings are Unicode strings in

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

       ·   We fixed a a minor error in perl5114delta.pod.

       ·   We replaced a mention of the now-obsolete with given/when.

       ·   We improved documentation about $sitelibexp/ in perlrun.

       ·   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 5.12.

       ·   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 perlfunc.pod

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


   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 installed.

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

           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 HP-UX

       ·   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 systems.

           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


       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 Arnfjoer` 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 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


       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.