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       This document describes differences between the 5.7.1
       release and the 5.7.2 release.

       (To view the differences between the 5.6.0 release and the
       5.7.0 release, see perl570delta.  To view the differences
       between the 5.7.0 release and the 5.7.1 release, see

Security Vulnerability Closed

       (This change was already made in 5.7.0 but bears repeating

       A security vulnerability affecting all Perl versions prior
       to 5.6.1 was found in August 2000.  The vulnerability does
       not affect default installations and as far as is known
       affects only the Linux platform.

       You should upgrade your Perl to 5.6.1 as soon as possible.
       Patches for earlier releases exist but using the patches
       require full recompilation from the source code anyway, so
       5.6.1 is your best choice.

       for more information.

Incompatible Changes

       64-bit platforms and malloc

       If your pointers are 64 bits wide, the Perl malloc is no
       more being used because it simply does not work with
       8-byte pointers.  Also, usually the system malloc on such
       platforms are much better optimized for such large memory
       models than the Perl malloc.

       AIX Dynaloading

       The AIX dynaloading now uses in AIX releases 4.3 and newer
       the native dlopen interface of AIX instead of the old emu­
       lated interface.  This change will probably break backward
       compatibility with compiled modules.  The change was made
       to make Perl more compliant with other applications like
       modperl which are using the AIX native interface.

       Socket Extension Dynamic in VMS

       The Socket extension is now dynamically loaded instead of
       being statically built in.  This may or may not be a prob­
       lem with ancient TCP/IP stacks of VMS: we do not know
       since we weren't able to test Perl in such configurations.

       In general this change results in more inclusive Unicode
       character classes, but changes to the other direction also
       do take place: for example while the script "Latin"
       includes all the Latin characters and their various dia­
       critic-adorned versions, it does not include the various
       punctuation or digits (since they are not solely "Latin").

       Changes in the character class semantics may have happened
       if a script and a block happen to have the same name, for
       example "Hebrew".  In such cases the script wins and
       "\p{InHebrew}" now means the script definition of Hebrew.
       The block definition in still available, though, by
       appending "Block" to the name: "\p{InHebrewBlock}" means
       what "\p{InHebrew}" meant in perl 5.6.0.  For the full
       list of affected character classes, see "Blocks" in perlu­


       The current user-visible implementation of pseudo-hashes
       (the weird use of the first array element) is deprecated
       starting from Perl 5.8.0 and will be removed in Perl
       5.10.0, and the feature will be implemented differently.
       Not only is the current interface rather ugly, but the
       current implementation slows down normal array and hash
       use quite noticeably. The "fields" pragma interface will
       remain available.

       The syntaxes "@a->[...]" and  "@h->{...}" have now been

       The suidperl is also considered to be too much a risk to
       continue maintaining and the suidperl code is likely to be
       removed in a future release.

       The "package;" syntax ("package" without an argument has
       been deprecated.  Its semantics were never that clear and
       its implementation even less so.  If you have used that
       feature to disallow all but fully qualified variables,
       "use strict;" instead.

       The chdir(undef) and chdir('') behaviors to match chdir()
       has been deprecated.  In future versions, chdir(undef) and
       chdir('') will simply fail.

Core Enhancements

       In general a lot of fixing has happened in the area of
       Perl's understanding of numbers, both integer and floating
       point.  Since in many systems the standard number parsing
       functions like "strtoul()" and "atof()" seem to have bugs,
       Perl tries to work around their deficiencies.  This

       ·   Lexicals II: lexicals leaked at file scope into sub­
           routines that were declared before the lexicals.

       ·   Lvalue subroutines can now return "undef" in list con­

       ·   The "op_clear" and "op_null" are now exported.

       ·   A new special regular expression variable has been
           introduced: $^N, which contains the most-recently
           closed group (submatch).

       ·   utime now supports "utime undef, undef, @files" to
           change the file timestamps to the current time.

       ·   The Perl parser has been stress tested using both ran­
           dom input and Markov chain input.

       ·   "eval "v200"" now works.

       ·   VMS now works under PerlIO.

       ·   END blocks are now run even if you exit/die in a BEGIN
           block.  The execution of END blocks is now controlled
           by PL_exit_flags & PERL_EXIT_DESTRUCT_END. This
           enables the new behaviour for perl embedders. This
           will default in 5.10. See perlembed.

Modules and Pragmata

       New Modules and Distributions

       ·   Attribute::Handlers - Simpler definition of attribute

       ·   ExtUtils::Constant - generate XS code to import C
           header constants

       ·   I18N::Langinfo - query locale information

       ·   I18N::LangTags - functions for dealing with
           RFC3066-style language tags

       ·   libnet - a collection of perl5 modules related to net­
           work programming

           Perl installation leaves libnet unconfigured, use lib­
           netcfg to configure.

       ·   List::Util - selection of general-utility list subrou­

       ·   Test::Simple - Basic utilities for writing tests

       ·   Time::HiRes - high resolution ualarm, usleep, and get­

       ·   Time::Piece - Object Oriented time objects

           (Previously known as Time::Object.)

       ·   Time::Seconds - a simple API to convert seconds to
           other date values

       ·   UnicodeCD - Unicode Character Database

       Updated And Improved Modules and Pragmata

       ·   B::Deparse module has been significantly enhanced.  It
           now can deparse almost all of the standard test suite
           (so that the tests still succeed).  There is a make
           target "test.deparse" for trying this out.

       ·   Class::Struct now assigns the array/hash element if
           the accessor is called with an array/hash element as
           the sole argument.

       ·   Cwd extension is now (even) faster.

       ·   DB_File extension has been updated to version 1.77.

       ·   Fcntl, Socket, and Sys::Syslog have been rewritten to
           use the new-style constant dispatch section (see ExtU­

       ·   File::Find is now (again) reentrant.  It also has been
           made more portable.

       ·   File::Glob now supports "GLOB_LIMIT" constant to limit
           the size of the returned list of filenames.

       ·   IO::Socket::INET now supports "LocalPort" of zero
           (usually meaning that the operating system will make
           one up.)

       ·   The vars pragma now supports declaring fully qualified
           variables.  (Something that "our()" does not and will
           not support.)

Utility Changes

       ·   The emacs/e2ctags.pl is now much faster.

       ·   h2ph now supports C trigraphs.

       ·   The Pod::Html (and thusly pod2html) now allows speci­
           fying a cache directory.

New Documentation

       ·   Locale::Maketext::TPJ13 is an article about software
           localization, originally published in The Perl Journal
           #13, republished here with kind permission.

       ·   More README.$PLATFORM files have been converted into
           pod, which also means that they also be installed as
           perl$PLATFORM documentation files.  The new files are
           perlapollo, perlbeos, perldgux, perlhurd, perlmint,
           perlnetware, perlplan9, perlqnx, and perltru64.

       ·   The Todo and Todo-5.6 files have been merged into

       ·   Use of the gprof tool to profile Perl has been docu­
           mented in perlhack.  There is a make target
           "perl.gprof" for generating a gprofiled Perl exe­

Installation and Configuration Improvements

       New Or Improved Platforms

       ·   AIX should now work better with gcc, threads, and
           64-bitness.  Also the long doubles support in AIX
           should be better now.  See perlaix.

       ·   AtheOS ( http://www.atheos.cx/ ) is a new platform.

       ·   DG/UX platform now supports the 5.005-style threads.
           See perldgux.

       ·   DYNIX/ptx platform (a.k.a. dynixptx) is supported at
           or near osvers 4.5.2.

       ·   Several Mac OS (Classic) portability patches have been
           applied.  We hope to get a fully working port by
           5.8.0.  (The remaining problems relate to the changed
           IO model of Perl.)  See perlmacos.

       ·   Mac OS X (or Darwin) should now be able to build Perl
           even on HFS+ filesystems.  (The case-insensitivity
           confused the Perl build process.)

       ·   NetWare from Novell is now supported.  See perlnet­

       ·   The Amdahl UTS UNIX mainframe platform is now sup­
           SION_PATCH_CFG" from C.

       ·   The Thread extension is now not built at all under
           ithreads ("Configure -Duseithreads") because it
           wouldn't work anyway (the Thread extension requires
           being Configured with "-Duse5005threads").

       ·   The "B::Deparse" compiler backend has been so signifi­
           cantly improved that almost the whole Perl test suite
           passes after being deparsed.  A make target has been
           added to help in further testing: "make test.deparse".

Selected Bug Fixes

       ·    The autouse pragma didn't work for Multi::Part::Func­

       ·    The behaviour of non-decimal but numeric string con­
            stants such as "0x23" was platform-dependent: in some
            platforms that was seen as 35, in some as 0, in some
            as a floating point number (don't ask).  This was
            caused by Perl using the operating system libraries
            in a situation where the result of the string to num­
            ber conversion is undefined: now Perl consistently
            handles such strings as zero in numeric contexts.

       ·    dprofpp -R didn't work.

       ·    PERL5OPT with embedded spaces didn't work.

       ·    Sys::Syslog ignored the "LOG_AUTH" constant.

       Platform Specific Changes and Fixes

       ·   Some versions of glibc have a broken modfl().  This
           affects builds with "-Duselongdouble".  This version
           of Perl detects this brokenness and has a workaround
           for it.  The glibc release 2.2.2 is known to have
           fixed the modfl() bug.

New or Changed Diagnostics

       ·   In the regular expression diagnostics the "<< HERE"
           marker introduced in 5.7.0 has been changed to be "<--
           HERE" since too many people found the "<<" to be too
           similar to here-document starters.

       ·   If you try to "pack" in perlfunc a number less than 0
           or larger than 255 using the "C" format you will get
           an optional warning.  Similarly for the "c" format and
           a number less than -128 or more than 127.

       Better commented code

       perly.c, sv.c, and sv.h have now been extensively com­

       Regex pre-/post-compilation items matched up

       The regex compiler now maintains a structure that identi­
       fies nodes in the compiled bytecode with the corresponding
       syntactic features of the original regex expression.  The
       information is attached to the new "offsets" member of the
       "struct regexp". See perldebguts for more complete infor­

       gcc -Wall

       The C code has been made much more "gcc -Wall" clean.
       Some warning messages still remain, though, so if you are
       compiling with gcc you will see some warnings about dubi­
       ous practices.  The warnings are being worked on.

New Tests

       Several new tests have been added, especially for the lib

       The tests are now reported in a different order than in
       earlier Perls.  (This happens because the test scripts
       from under t/lib have been moved to be closer to the
       library/extension they are testing.)

Known Problems

       Note that unlike other sections in this document (which
       describe changes since 5.7.0) this section is cumulative
       containing known problems for all the 5.7 releases.


       ·   In AIX 4.2 Perl extensions that use C++ functions that
           use statics may have problems in that the statics are
           not getting initialized.  In newer AIX releases this
           has been solved by linking Perl with the libC_r
           library, but unfortunately in AIX 4.2 the said library
           has an obscure bug where the various functions related
           to time (such as time() and gettimeofday()) return
           broken values, and therefore in AIX 4.2 Perl is not
           linked against the libC_r.

       ·   vac May Produce Buggy Code For Perl

           The AIX C compiler vac version may produce

       lib/ftmp-security tests warn 'system possibly insecure'

       Don't panic.  Read INSTALL 'make test' section instead.

       Cygwin intermittent failures of lib/Memoize/t/expire_file
       11 and 12

       The subtests 11 and 12 sometimes fail and sometimes work.

       HP-UX lib/io_multihomed Fails When LP64-Configured

       The lib/io_multihomed test may hang in HP-UX if Perl has
       been configured to be 64-bit. Because other 64-bit plat­
       forms do not hang in this test, HP-UX is suspect. All
       other tests pass in 64-bit HP-UX. The test attempts to
       create and connect to "multihomed" sockets (sockets which
       have multiple IP addresses).

       HP-UX lib/posix Subtest 9 Fails When LP64-Configured

       If perl is configured with -Duse64bitall, the successful
       result of the subtest 10 of lib/posix may arrive before
       the successful result of the subtest 9, which confuses the
       test harness so much that it thinks the subtest 9 failed.

       Linux With Sfio Fails op/misc Test 48

       No known fix.


       OS/390 has rather many test failures but the situation is
       actually better than it was in 5.6.0, it's just that so
       many new modules and tests have been added.

        Failed Test                     Stat Wstat Total Fail  Failed  List of Failed
        ../ext/B/Deparse.t                            14    1   7.14%  14
        ../ext/B/Showlex.t                             1    1 100.00%  1
        ../ext/Encode/Encode/Tcl.t                   610   13   2.13%  592 594 596 598
                                                                       600 602 604-610
        ../ext/IO/lib/IO/t/io_unix.t     113 28928     5    3  60.00%  3-5
        ../ext/POSIX/POSIX.t                          29    1   3.45%  14
        ../ext/Storable/t/lock.t         255 65280     5    3  60.00%  3-5
        ../lib/locale.t                  129 33024   117   19  16.24%  99-117
        ../lib/warnings.t                            434    1   0.23%  75
        ../lib/ExtUtils.t                             27    1   3.70%  25
        ../lib/Math/BigInt/t/bigintpm.t             1190    1   0.08%  1145
        ../lib/Unicode/UCD.t                          81   48  59.26%  1-16 49-64 66-81
        ../lib/User/pwent.t                            9    1  11.11%  4
        op/pat.t                                     660    6   0.91%  242-243 424-425

       ANSI X3.159 1989 to be exact.  (They produce something
       other than "1" and "-1" when formatting 0.6 and -0.6 using
       the printf format "%.0f", most often they produce "0" and

       Failure of Thread tests

       Note that support for 5.005-style threading remains exper­

       The following tests are known to fail due to fundamental
       problems in the 5.005 threading implementation. These are
       not new failures--Perl 5.005_0x has the same bugs, but
       didn't have these tests.

         lib/autouse.t                 4
         t/lib/thr5005.t               19-20


       ·   ext/POSIX/sigaction subtests 6 and 13 may fail.

       ·   lib/ExtUtils may spuriously claim that subtest 28
           failed, which is interesting since the test only has
           27 tests.

       ·   Numerous numerical test failures

             op/numconvert                 209,210,217,218
             op/override                   7
             ext/Time/HiRes/HiRes          9
             lib/Math/BigInt/t/bigintpm    1145
             lib/Math/Trig                 25

           These tests fail because of yet unresolved floating
           point inaccuracies.


       There are a few known test failures, see perluts.


       Rather many tests are failing in VMS but that actually
       more tests succeed in VMS than they used to, it's just
       that there are many, many more tests than there used to

       Here are the known failures from some compiler/platform

         [.op]sprintf............................FAILED on test 12
         Failed 8/399 tests, 91.23% okay.

       DEC C V6.0-001 on OpenVMS Alpha V7.2-1 and Compaq C
       V6.2-008 on OpenVMS Alpha V7.1

         [-.ext.list.util.t]tainted..............FAILED on test 3
         [-.lib.file.find]taint..................FAILED on test 17
         [-.lib.test.simple.t]exit...............FAILED on test 1
         [.lib]vmsish............................FAILED on test 13
         Failed 4/399 tests, 92.48% okay.

       Compaq C V6.4-005 on OpenVMS Alpha 7.2.1

         [-.ext.b]showlex........................FAILED on test 1
         [-.ext.list.util.t]tainted..............FAILED on test 3
         [-.lib.file.find]taint..................FAILED on test 17
         [-.lib.test.simple.t]exit...............FAILED on test 1
         [.lib]vmsish............................FAILED on test 13
         [.op]misc...............................FAILED on test 49
         Failed 6/401 tests, 92.77% okay.


       In multi-CPU boxes there are some problems with the I/O
       buffering: some output may appear twice.

       Localising a Tied Variable Leaks Memory

           use Tie::Hash;
           tie my %tie_hash => 'Tie::StdHash';


           local($tie_hash{Foo}) = 1; # leaks

       Code like the above is known to leak memory every time the
       local() is executed.

       Self-tying of Arrays and Hashes Is Forbidden

       Self-tying of arrays and hashes is broken in rather deep
       and hard-to-fix ways.  As a stop-gap measure to avoid peo­
       ple from getting frustrated at the mysterious results
       (core dumps, most often) it is for now forbidden (you will
       get a fatal error even from an attempt).

       Variable Attributes are not Currently Usable for Tieing

       This limitation will hopefully be fixed in future.  (Sub­
       routine attributes work fine for tieing, see
       all.  One potential failure is whether one can (or, if one
       can, whether it's a good idea) link together at all bina­
       ries with different ideas about file offsets, all this is

       The Compiler Suite Is Still Experimental

       The compiler suite is slowly getting better but is nowhere
       near working order yet.

       The Long Double Support is Still Experimental

       The ability to configure Perl's numbers to use "long dou­
       bles", floating point numbers of hopefully better accu­
       racy, is still experimental.  The implementations of long
       doubles are not yet widespread and the existing implemen­
       tations are not quite mature or standardised, therefore
       trying to support them is a rare and moving target.  The
       gain of more precision may also be offset by slowdown in
       computations (more bits to move around, and the operations
       are more likely to be executed by less optimised

Reporting Bugs

       If you find what you think is a bug, you might check the
       articles recently posted to the comp.lang.perl.misc news­
       group and the perl bug database at http://bugs.perl.org/
       There may also be information at http://www.perl.com/perl/
       , 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 perlbug@perl.org to be analysed by the Perl
       porting team.


       The Changes file for 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.


       Written by Jarkko Hietaniemi <jhi@iki.fi>, with many con­
       tributions from The Perl Porters and Perl Users submitting
       feedback and patches.

       Send omissions or corrections to <perlbug@perl.org>.



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