perl58delta - what is new for perl v5.8.0


   This document describes differences between the 5.6.0 release and the
   5.8.0 release.

   Many of the bug fixes in 5.8.0 were already seen in the 5.6.1
   maintenance release since the two releases were kept closely
   coordinated (while 5.8.0 was still called 5.7.something).

   Changes that were integrated into the 5.6.1 release are marked "[561]".
   Many of these changes have been further developed since 5.6.1 was
   released, those are marked "[561+]".

   You can see the list of changes in the 5.6.1 release (both from the
   5.005_03 release and the 5.6.0 release) by reading perl561delta.

Highlights In 5.8.0

   *   Better Unicode support

   *   New IO Implementation

   *   New Thread Implementation

   *   Better Numeric Accuracy

   *   Safe Signals

   *   Many New Modules

   *   More Extensive Regression Testing

Incompatible Changes

   Binary Incompatibility
   Perl 5.8 is not binary compatible with earlier releases of Perl.

   You have to recompile your XS modules.

   (Pure Perl modules should continue to work.)

   The major reason for the discontinuity is the new IO architecture
   called PerlIO.  PerlIO is the default configuration because without it
   many new features of Perl 5.8 cannot be used.  In other words: you just
   have to recompile your modules containing XS code, sorry about that.

   In future releases of Perl, non-PerlIO aware XS modules may become
   completely unsupported.  This shouldn't be too difficult for module
   authors, however: PerlIO has been designed as a drop-in replacement (at
   the source code level) for the stdio interface.

   Depending on your platform, there are also other reasons why we decided
   to break binary compatibility, please read on.

   64-bit platforms and malloc
   If your pointers are 64 bits wide, the Perl malloc is no longer being
   used because it does not work well with 8-byte pointers.  Also, usually
   the system mallocs on such platforms are much better optimized for such
   large memory models than the Perl malloc.  Some memory-hungry Perl
   applications like the PDL don't work well with Perl's malloc.  Finally,
   other applications than Perl (such as mod_perl) tend to prefer the
   system malloc.  Such platforms include Alpha and 64-bit HPPA, MIPS,
   PPC, and Sparc.

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

   Attributes for "my" variables now handled at run-time
   The "my EXPR : ATTRS" syntax now applies variable attributes at run-
   time.  (Subroutine and "our" variables still get attributes applied at
   compile-time.)  See attributes for additional details.  In particular,
   however, this allows variable attributes to be useful for "tie"
   interfaces, which was a deficiency of earlier releases.  Note that the
   new semantics doesn't work with the Attribute::Handlers module (as of
   version 0.76).

   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 problem with ancient
   TCP/IP stacks of VMS: we do not know since we weren't able to test Perl
   in such configurations.

   IEEE-format Floating Point Default on OpenVMS Alpha
   Perl now uses IEEE format (T_FLOAT) as the default internal floating
   point format on OpenVMS Alpha, potentially breaking binary
   compatibility with external libraries or existing data.  G_FLOAT is
   still available as a configuration option.  The default on VAX
   (D_FLOAT) has not changed.

   New Unicode Semantics (no more "use utf8", almost)
   Previously in Perl 5.6 to use Unicode one would say "use utf8" and then
   the operations (like string concatenation) were Unicode-aware in that
   lexical scope.

   This was found to be an inconvenient interface, and in Perl 5.8 the
   Unicode model has completely changed: now the "Unicodeness" is bound to
   the data itself, and for most of the time "use utf8" is not needed at
   all.  The only remaining use of "use utf8" is when the Perl script
   itself has been written in the UTF-8 encoding of Unicode.  (UTF-8 has
   not been made the default since there are many Perl scripts out there
   that are using various national eight-bit character sets, which would
   be illegal in UTF-8.)

   See perluniintro for the explanation of the current model, and utf8 for
   the current use of the utf8 pragma.

   New Unicode Properties
   Unicode scripts are now supported. Scripts are similar to (and superior
   to) Unicode blocks. The difference between scripts and blocks is that
   scripts are the glyphs used by a language or a group of languages,
   while the blocks are more artificial groupings of (mostly) 256
   characters based on the Unicode numbering.

   In general, scripts are more inclusive, but not universally so. For
   example, while the script "Latin" includes all the Latin characters and
   their various diacritic-adorned versions, it does not include the
   various punctuation or digits (since they are not solely "Latin").

   A number of other properties are now supported, including "\p{L&}",
   "\p{Any}" "\p{Assigned}", "\p{Unassigned}", "\p{Blank}" [561] and
   "\p{SpacePerl}" [561] (along with their "\P{...}" versions, of course).
   See perlunicode for details, and more additions.

   The "In" or "Is" prefix to names used with the "\p{...}" and "\P{...}"
   are now almost always optional. The only exception is that a "In"
   prefix is required to signify a Unicode block when a block name
   conflicts with a script name. For example, "\p{Tibetan}" refers to the
   script, while "\p{InTibetan}" refers to the block. When there is no
   name conflict, you can omit the "In" from the block name (e.g.
   "\p{BraillePatterns}"), but to be safe, it's probably best to always
   use the "In").

   REF(...) Instead Of SCALAR(...)
   A reference to a reference now stringifies as "REF(0x81485ec)" instead
   of "SCALAR(0x81485ec)" in order to be more consistent with the return
   value of ref().

   pack/unpack D/F recycled
   The undocumented pack/unpack template letters D/F have been recycled
   for better use: now they stand for long double (if supported by the
   platform) and NV (Perl internal floating point type).  (They used to be
   aliases for d/f, but you never knew that.)

   glob() now returns filenames in alphabetical order
   The list of filenames from glob() (or <...>) is now by default sorted
   alphabetically to be csh-compliant (which is what happened before in
   most Unix platforms).  (bsd_glob() does still sort platform natively,
   ASCII or EBCDIC, unless GLOB_ALPHASORT is specified.) [561]

   *   The semantics of bless(REF, REF) were unclear and until someone
       proves it to make some sense, it is forbidden.

   *   The obsolete chat2 library that should never have been allowed to
       escape the laboratory has been decommissioned.

   *   Using chdir("") or chdir(undef) instead of explicit chdir() is
       doubtful.  A failure (think chdir(some_function()) can lead into
       unintended chdir() to the home directory, therefore this behaviour
       is deprecated.

   *   The builtin dump() function has probably outlived most of its
       usefulness.  The core-dumping functionality will remain in future
       available as an explicit call to "CORE::dump()", but in future
       releases the behaviour of an unqualified "dump()" call may change.

   *   The very dusty examples in the eg/ directory have been removed.
       Suggestions for new shiny examples welcome but the main issue is
       that the examples need to be documented, tested and (most
       importantly) maintained.

   *   The (bogus) escape sequences \8 and \9 now give an optional warning
       ("Unrecognized escape passed through").  There is no need to
       \-escape any "\w" character.

   *   The *glob{FILEHANDLE} is deprecated, use *glob{IO} instead.

   *   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 unimplemented POSIX regex features [[.cc.]] and [[=c=]] are
       still recognised but now cause fatal errors.  The previous
       behaviour of ignoring them by default and warning if requested was
       unacceptable since it, in a way, falsely promised that the features
       could be used.

   *   In future releases, non-PerlIO aware XS modules may become
       completely unsupported.  Since PerlIO is a drop-in replacement for
       stdio at the source code level, this shouldn't be that drastic a

   *   Previous versions of perl and some readings of some sections of
       Camel III implied that the ":raw" "discipline" was the inverse of
       ":crlf".  Turning off "clrfness" is no longer enough to make a
       stream truly binary. So the PerlIO ":raw" layer (or "discipline",
       to use the Camel book's older terminology) is now formally defined
       as being equivalent to binmode(FH) - which is in turn defined as
       doing whatever is necessary to pass each byte as-is without any
       translation.  In particular binmode(FH) - and hence ":raw" - will
       now turn off both CRLF and UTF-8 translation and remove other
       layers (e.g. :encoding()) which would modify byte stream.

   *   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 restricted hashes interface is expected to
       be the replacement interface (see Hash::Util).  If your existing
       programs depends on the underlying implementation, consider using
       Class::PseudoHash from CPAN.

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

   *   After years of trying, suidperl is considered to be too complex to
       ever be considered truly secure.  The suidperl functionality is
       likely to be removed in a future release.

   *   The 5.005 threads model (module "Thread") is deprecated and
       expected to be removed in Perl 5.10.  Multithreaded code should be
       migrated to the new ithreads model (see threads, threads::shared
       and perlthrtut).

   *   The long deprecated uppercase aliases for the string comparison
       operators (EQ, NE, LT, LE, GE, GT) have now been removed.

   *   The tr///C and tr///U features have been removed and will not
       return; the interface was a mistake.  Sorry about that.  For
       similar functionality, see pack('U0', ...) and pack('C0', ...).

   *   Earlier Perls treated "sub foo (@bar)" as equivalent to "sub foo
       (@)".  The prototypes are now checked better at compile-time for
       invalid syntax.  An optional warning is generated ("Illegal
       character in prototype...")  but this may be upgraded to a fatal
       error in a future release.

   *   The "exec LIST" and "system LIST" operations now produce warnings
       on tainted data and in some future release they will produce fatal

   *   The existing behaviour when localising tied arrays and hashes is
       wrong, and will be changed in a future release, so do not rely on
       the existing behaviour. See "Localising Tied Arrays and Hashes Is

Core Enhancements

   Unicode Overhaul
   Unicode in general should be now much more usable than in Perl 5.6.0
   (or even in 5.6.1).  Unicode can be used in hash keys, Unicode in
   regular expressions should work now, Unicode in tr/// should work now,
   Unicode in I/O should work now.  See perluniintro for introduction and
   perlunicode for details.

   *   The Unicode Character Database coming with Perl has been upgraded
       to Unicode 3.2.0.  For more information, see .  [561+] (5.6.1 has UCD 3.0.1.)

   *   For developers interested in enhancing Perl's Unicode capabilities:
       almost all the UCD files are included with the Perl distribution in
       the lib/unicore subdirectory.  The most notable omission, for space
       considerations, is the Unihan database.

   *   The properties \p{Blank} and \p{SpacePerl} have been added. "Blank"
       is like C isblank(), that is, it contains only "horizontal
       whitespace" (the space character is, the newline isn't), and the
       "SpacePerl" is the Unicode equivalent of "\s" (\p{Space} isn't,
       since that includes the vertical tabulator character, whereas "\s"

       See "New Unicode Properties" earlier in this document for
       additional information on changes with Unicode properties.

   PerlIO is Now The Default
   *   IO is now by default done via PerlIO rather than system's "stdio".
       PerlIO allows "layers" to be "pushed" onto a file handle to alter
       the handle's behaviour.  Layers can be specified at open time via
       3-arg form of open:

          open($fh,'>:crlf :utf8', $path) || ...

       or on already opened handles via extended "binmode":


       The built-in layers are: unix (low level read/write), stdio (as in
       previous Perls), perlio (re-implementation of stdio buffering in a
       portable manner), crlf (does CRLF <=> "\n" translation as on Win32,
       but available on any platform).  A mmap layer may be available if
       platform supports it (mostly Unixes).

       Layers to be applied by default may be specified via the 'open'

       See "Installation and Configuration Improvements" for the effects
       of PerlIO on your architecture name.

   *   If your platform supports fork(), you can use the list form of
       "open" for pipes.  For example:

           open KID_PS, "-|", "ps", "aux" or die $!;

       forks the ps(1) command (without spawning a shell, as there are
       more than three arguments to open()), and reads its standard output
       via the "KID_PS" filehandle.  See perlipc.

   *   File handles can be marked as accepting Perl's internal encoding of
       Unicode (UTF-8 or UTF-EBCDIC depending on platform) by a pseudo
       layer ":utf8" :


       Note for EBCDIC users: the pseudo layer ":utf8" is erroneously
       named for you since it's not UTF-8 what you will be getting but
       instead UTF-EBCDIC.  See perlunicode, utf8, and for more information.
       In future releases this naming may change.  See perluniintro for
       more information about UTF-8.

   *   If your environment variables (LC_ALL, LC_CTYPE, LANG) look like
       you want to use UTF-8 (any of the variables match "/utf-?8/i"),
       your STDIN, STDOUT, STDERR handles and the default open layer (see
       open) are marked as UTF-8.  (This feature, like other new features
       that combine Unicode and I/O, work only if you are using PerlIO,
       but that's the default.)

       Note that after this Perl really does assume that everything is
       UTF-8: for example if some input handle is not, Perl will probably
       very soon complain about the input data like this "Malformed UTF-8
       ..." since any old eight-bit data is not legal UTF-8.

       Note for code authors: if you want to enable your users to use
       UTF-8 as their default encoding  but in your code still have eight-
       bit I/O streams (such as images or zip files), you need to
       explicitly open() or binmode() with ":bytes" (see "open" in
       perlfunc and "binmode" in perlfunc), or you can just use
       "binmode(FH)" (nice for pre-5.8.0 backward compatibility).

   *   File handles can translate character encodings from/to Perl's
       internal Unicode form on read/write via the ":encoding()" layer.

   *   File handles can be opened to "in memory" files held in Perl
       scalars via:

          open($fh,'>', \$variable) || ...

   *   Anonymous temporary files are available without need to 'use
       FileHandle' or other module via

          open($fh,"+>", undef) || ...

       That is a literal undef, not an undefined value.

   The new interpreter threads ("ithreads" for short) implementation of
   multithreading, by Arthur Bergman, replaces the old "5.005 threads"
   implementation.  In the ithreads model any data sharing between threads
   must be explicit, as opposed to the model where data sharing was
   implicit.  See threads and threads::shared, and perlthrtut.

   As a part of the ithreads implementation Perl will also use any
   necessary and detectable reentrant libc interfaces.

   Restricted Hashes
   A restricted hash is restricted to a certain set of keys, no keys
   outside the set can be added.  Also individual keys can be restricted
   so that the key cannot be deleted and the value cannot be changed.  No
   new syntax is involved: the Hash::Util module is the interface.

   Safe Signals
   Perl used to be fragile in that signals arriving at inopportune moments
   could corrupt Perl's internal state.  Now Perl postpones handling of
   signals until it's safe (between opcodes).

   This change may have surprising side effects because signals no longer
   interrupt Perl instantly.  Perl will now first finish whatever it was
   doing, like finishing an internal operation (like sort()) or an
   external operation (like an I/O operation), and only then look at any
   arrived signals (and before starting the next operation).  No more
   corrupt internal state since the current operation is always finished
   first, but the signal may take more time to get heard.  Note that
   breaking out from potentially blocking operations should still work,

   Understanding of Numbers
   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 results hopefully in more accurate numbers.

   Perl now tries internally to use integer values in numeric conversions
   and basic arithmetics (+ - * /) if the arguments are integers, and
   tries also to keep the results stored internally as integers.  This
   change leads to often slightly faster and always less lossy
   arithmetics. (Previously Perl always preferred floating point numbers
   in its math.)

   Arrays now always interpolate into double-quoted strings [561]
   In double-quoted strings, arrays now interpolate, no matter what.  The
   behavior in earlier versions of perl 5 was that arrays would
   interpolate into strings if the array had been mentioned before the
   string was compiled, and otherwise Perl would raise a fatal compile-
   time error.  In versions 5.000 through 5.003, the error was

           Literal @example now requires backslash

   In versions 5.004_01 through 5.6.0, the error was

           In string, @example now must be written as \@example

   The idea here was to get people into the habit of writing
   "fred\" when they wanted a literal "@" sign, just as they
   have always written "Give me back my \$5" when they wanted a literal
   "$" sign.

   Starting with 5.6.1, when Perl now sees an "@" sign in a double-quoted
   string, it always attempts to interpolate an array, regardless of
   whether or not the array has been used or declared already.  The fatal
   error has been downgraded to an optional warning:

           Possible unintended interpolation of @example in string

   This warns you that "" is going to turn into ""
   if you don't backslash the "@".  See for more details about the history

   Miscellaneous Changes
   *   AUTOLOAD is now lvaluable, meaning that you can add the :lvalue
       attribute to AUTOLOAD subroutines and you can assign to the
       AUTOLOAD return value.

   *   The $Config{byteorder} (and corresponding BYTEORDER in config.h)
       was previously wrong in platforms if sizeof(long) was 4, but
       sizeof(IV) was 8.  The byteorder was only sizeof(long) bytes long
       (1234 or 4321), but now it is correctly sizeof(IV) bytes long,
       (12345678 or 87654321).  (This problem didn't affect Windows

       Also, $Config{byteorder} is now computed dynamically--this is more
       robust with "fat binaries" where an executable image contains
       binaries for more than one binary platform, and when cross-

   *   "perl -d:Module=arg,arg,arg" now works (previously one couldn't
       pass in multiple arguments.)

   *   "do" followed by a bareword now ensures that this bareword isn't a
       keyword (to avoid a bug where "do q(" tried to call a
       subroutine called "q").  This means that for example instead of "do
       format()" you must write "do &format()".

   *   The builtin dump() now gives an optional warning "dump() better
       written as CORE::dump()", meaning that by default "dump(...)" is
       resolved as the builtin dump() which dumps core and aborts, not as
       (possibly) user-defined "sub dump".  To call the latter, qualify
       the call as "&dump(...)".  (The whole dump() feature is to
       considered deprecated, and possibly removed/changed in future

   *   chomp() and chop() are now overridable.  Note, however, that their
       prototype (as given by "prototype("CORE::chomp")" is undefined,
       because it cannot be expressed and therefore one cannot really
       write replacements to override these builtins.

   *   END blocks are now run even if you exit/die in a BEGIN block.
       Internally, 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

   *   Formats now support zero-padded decimal fields.

   *   Although "you shouldn't do that", it was possible to write code
       that depends on Perl's hashed key order (Data::Dumper does this).
       The new algorithm "One-at-a-Time" produces a different hashed key
       order.  More details are in "Performance Enhancements".

   *   lstat(FILEHANDLE) now gives a warning because the operation makes
       no sense.  In future releases this may become a fatal error.

   *   Spurious syntax errors generated in certain situations, when glob()
       caused File::Glob to be loaded for the first time, have been fixed.

   *   Lvalue subroutines can now return "undef" in list context.
       However, the lvalue subroutine feature still remains experimental.

   *   A lost warning "Can't declare ... dereference in my" has been
       restored (Perl had it earlier but it became lost in later

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

   *   "no Module;" does not produce an error even if Module does not have
       an unimport() method.  This parallels the behavior of "use" vis-a-
       vis "import". [561]

   *   The numerical comparison operators return "undef" if either operand
       is a NaN.  Previously the behaviour was unspecified.

   *   "our" can now have an experimental optional attribute "unique" that
       affects how global variables are shared among multiple
       interpreters, see "our" in perlfunc.

   *   The following builtin functions are now overridable: each(),
       keys(), pop(), push(), shift(), splice(), unshift(). [561]

   *   "pack() / unpack()" can now group template letters with "()" and
       then apply repetition/count modifiers on the groups.

   *   "pack() / unpack()" can now process the Perl internal numeric
       types: IVs, UVs, NVs-- and also long doubles, if supported by the
       platform.  The template letters are "j", "J", "F", and "D".

   *   "pack('U0a*', ...)" can now be used to force a string to UTF-8.

   *   my __PACKAGE__ $obj now works. [561]

   *   POSIX::sleep() now returns the number of unslept seconds (as the
       POSIX standard says), as opposed to CORE::sleep() which returns the
       number of slept seconds.

   *   printf() and sprintf() now support parameter reordering using the
       "%\d+\$" and "*\d+\$" syntaxes.  For example

           printf "%2\$s %1\$s\n", "foo", "bar";

       will print "bar foo\n".  This feature helps in writing
       internationalised software, and in general when the order of the
       parameters can vary.

   *   The (\&) prototype now works properly. [561]

   *   prototype(\[$@%&]) is now available to implicitly create references
       (useful for example if you want to emulate the tie() interface).

   *   A new command-line option, "-t" is available.  It is the little
       brother of "-T": instead of dying on taint violations, lexical
       warnings are given.  This is only meant as a temporary debugging
       aid while securing the code of old legacy applications.  This is
       not a substitute for -T.

   *   In other taint news, the "exec LIST" and "system LIST" have now
       been considered too risky (think "exec @ARGV": it can start any
       program with any arguments), and now the said forms cause a warning
       under lexical warnings.  You should carefully launder the arguments
       to guarantee their validity.  In future releases of Perl the forms
       will become fatal errors so consider starting laundering now.

   *   Tied hash interfaces are now required to have the EXISTS and DELETE
       methods (either own or inherited).

   *   If tr/// is just counting characters, it doesn't attempt to modify
       its target.

   *   untie() will now call an UNTIE() hook if it exists.  See perltie
       for details. [561]

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

   *   The rules for allowing underscores (underbars) in numeric constants
       have been relaxed and simplified: now you can have an underscore
       simply between digits.

   *   Rather than relying on C's argv[0] (which may not contain a full
       pathname) where possible $^X is now set by asking the operating
       system.  (eg by reading /proc/self/exe on Linux, /proc/curproc/file
       on FreeBSD)

   *   A new variable, "${^TAINT}", indicates whether taint mode is

   *   You can now override the readline() builtin, and this overrides
       also the <FILEHANDLE> angle bracket operator.

   *   The command-line options -s and -F are now recognized on the
       shebang (#!) line.

   *   Use of the "/c" match modifier without an accompanying "/g"
       modifier elicits a new warning: "Use of /c modifier is meaningless
       without /g".

       Use of "/c" in substitutions, even with "/g", elicits "Use of /c
       modifier is meaningless in s///".

       Use of "/g" with "split" elicits "Use of /g modifier is meaningless
       in split".

   *   Support for the "CLONE" special subroutine had been added.  With
       ithreads, when a new thread is created, all Perl data is cloned,
       however non-Perl data cannot be cloned automatically.  In "CLONE"
       you can do whatever you need to do, like for example handle the
       cloning of non-Perl data, if necessary.  "CLONE" will be executed
       once for every package that has it defined or inherited.  It will
       be called in the context of the new thread, so all modifications
       are made in the new area.

       See perlmod

Modules and Pragmata

   New Modules and Pragmata
   *   "Attribute::Handlers", originally by Damian Conway and now
       maintained by Arthur Bergman, allows a class to define attribute

           package MyPack;
           use Attribute::Handlers;
           sub Wolf :ATTR(SCALAR) { print "howl!\n" }

           # later, in some package using or inheriting from MyPack...

           my MyPack $Fluffy : Wolf; # the attribute handler Wolf will be called

       Both variables and routines can have attribute handlers.  Handlers
       can be specific to type (SCALAR, ARRAY, HASH, or CODE), or specific
       to the exact compilation phase (BEGIN, CHECK, INIT, or END).  See

   *   "B::Concise", by Stephen McCamant, is a new compiler backend for
       walking the Perl syntax tree, printing concise info about ops.  The
       output is highly customisable.  See B::Concise. [561+]

   *   The new bignum, bigint, and bigrat pragmas, by Tels, implement
       transparent bignum support (using the Math::BigInt, Math::BigFloat,
       and Math::BigRat backends).

   *   "Class::ISA", by Sean Burke, is a module for reporting the search
       path for a class's ISA tree.  See Class::ISA.

   *   "Cwd" now has a split personality: if possible, an XS extension is
       used, (this will hopefully be faster, more secure, and more robust)
       but if not possible, the familiar Perl implementation is used.

   *   "Devel::PPPort", originally by Kenneth Albanowski and now
       maintained by Paul Marquess, has been added.  It is primarily used
       by "h2xs" to enhance portability of XS modules between different
       versions of Perl.  See Devel::PPPort.

   *   "Digest", frontend module for calculating digests (checksums), from
       Gisle Aas, has been added.  See Digest.

   *   "Digest::MD5" for calculating MD5 digests (checksums) as defined in
       RFC 1321, from Gisle Aas, has been added.  See Digest::MD5.

           use Digest::MD5 'md5_hex';

           $digest = md5_hex("Thirsty Camel");

           print $digest, "\n"; # 01d19d9d2045e005c3f1b80e8b164de1

       NOTE: the "MD5" backward compatibility module is deliberately not
       included since its further use is discouraged.

       See also PerlIO::via::QuotedPrint.

   *   "Encode", originally by Nick Ing-Simmons and now maintained by Dan
       Kogai, provides a mechanism to translate between different
       character encodings.  Support for Unicode, ISO-8859-1, and ASCII
       are compiled in to the module.  Several other encodings (like the
       rest of the ISO-8859, CP*/Win*, Mac, KOI8-R, three variants EBCDIC,
       Chinese, Japanese, and Korean encodings) are included and can be
       loaded at runtime.  (For space considerations, the largest Chinese
       encodings have been separated into their own CPAN module,
       Encode::HanExtra, which Encode will use if available).  See Encode.

       Any encoding supported by Encode module is also available to the
       ":encoding()" layer if PerlIO is used.

   *   "Hash::Util" is the interface to the new restricted hashes feature.
       (Implemented by Jeffrey Friedl, Nick Ing-Simmons, and Michael
       Schwern.)  See Hash::Util.

   *   "I18N::Langinfo" can be used to query locale information.  See

   *   "I18N::LangTags", by Sean Burke, has functions for dealing with
       RFC3066-style language tags.  See I18N::LangTags.

   *   "ExtUtils::Constant", by Nicholas Clark, is a new tool for
       extension writers for generating XS code to import C header
       constants.  See ExtUtils::Constant.

   *   "Filter::Simple", by Damian Conway, is an easy-to-use frontend to
       Filter::Util::Call.  See Filter::Simple.

           # in

           package MyFilter;

           use Filter::Simple sub {
               while (my ($from, $to) = splice @_, 0, 2) {


           # in user's code:

           use MyFilter qr/red/ => 'green';

           print "red\n";   # this code is filtered, will print "green\n"
           print "bored\n"; # this code is filtered, will print "bogreen\n"

           no MyFilter;

           print "red\n";   # this code is not filtered, will print "red\n"

   *   "File::Temp", by Tim Jenness, allows one to create temporary files
       and directories in an easy, portable, and secure way.  See
       File::Temp.  [561+]

   *   "Filter::Util::Call", by Paul Marquess, provides you with the
       framework to write source filters in Perl.  For most uses, the
       frontend Filter::Simple is to be preferred.  See

   *   "if", by Ilya Zakharevich, is a new pragma for conditional
       inclusion of modules.

   *   libnet, by Graham Barr, is a collection of perl5 modules related to
       network programming.  See Net::FTP, Net::NNTP, Net::Ping (not part
       of libnet, but related), Net::POP3, Net::SMTP, and Net::Time.

       Perl installation leaves libnet unconfigured; use libnetcfg to
       configure it.

   *   "List::Util", by Graham Barr, is a selection of general-utility
       list subroutines, such as sum(), min(), first(), and shuffle().
       See List::Util.

   *   "Locale::Constants", "Locale::Country", "Locale::Currency"
       "Locale::Language", and Locale::Script, by Neil Bowers, have been
       added.  They provide the codes for various locale standards, such
       as "fr" for France, "usd" for US Dollar, and "ja" for Japanese.

           use Locale::Country;

           $country = code2country('jp');               # $country gets 'Japan'
           $code    = country2code('Norway');           # $code gets 'no'

       See Locale::Constants, Locale::Country, Locale::Currency, and

   *   "Locale::Maketext", by Sean Burke, is a localization framework.
       See Locale::Maketext, and Locale::Maketext::TPJ13.  The latter is
       an article about software localization, originally published in The
       Perl Journal #13, and republished here with kind permission.

   *   "Math::BigRat" for big rational numbers, to accompany Math::BigInt
       and Math::BigFloat, from Tels.  See Math::BigRat.

   *   "Memoize" can make your functions faster by trading space for time,
       from Mark-Jason Dominus.  See Memoize.

   *   "MIME::Base64", by Gisle Aas, allows you to encode data in base64,
       as defined in RFC 2045 - MIME (Multipurpose Internet Mail

           use MIME::Base64;

           $encoded = encode_base64('Aladdin:open sesame');
           $decoded = decode_base64($encoded);

           print $encoded, "\n"; # "QWxhZGRpbjpvcGVuIHNlc2FtZQ=="

       See MIME::Base64.

   *   "MIME::QuotedPrint", by Gisle Aas, allows you to encode data in
       quoted-printable encoding, as defined in RFC 2045 - MIME
       (Multipurpose Internet Mail Extensions).

           use MIME::QuotedPrint;

           $encoded = encode_qp("\xDE\xAD\xBE\xEF");
           $decoded = decode_qp($encoded);

           print $encoded, "\n"; # "=DE=AD=BE=EF\n"
           print $decoded, "\n"; # "\xDE\xAD\xBE\xEF\n"

       See also PerlIO::via::QuotedPrint.

   *   "NEXT", by Damian Conway, is a pseudo-class for method redispatch.
       See NEXT.

   *   "open" is a new pragma for setting the default I/O layers for

   *   "PerlIO::scalar", by Nick Ing-Simmons, provides the implementation
       of IO to "in memory" Perl scalars as discussed above.  It also
       serves as an example of a loadable PerlIO layer.  Other future
       possibilities include PerlIO::Array and PerlIO::Code.  See

   *   "PerlIO::via", by Nick Ing-Simmons, acts as a PerlIO layer and
       wraps PerlIO layer functionality provided by a class (typically
       implemented in Perl code).

   *   "PerlIO::via::QuotedPrint", by Elizabeth Mattijsen, is an example
       of a "PerlIO::via" class:

           use PerlIO::via::QuotedPrint;

       This will automatically convert everything output to $fh to Quoted-
       Printable.  See PerlIO::via and PerlIO::via::QuotedPrint.

   *   "Pod::ParseLink", by Russ Allbery, has been added, to parse L<>
       links in pods as described in the new perlpodspec.

   *   "Pod::Text::Overstrike", by Joe Smith, has been added.  It converts
       POD data to formatted overstrike text.  See Pod::Text::Overstrike.

   *   "Scalar::Util" is a selection of general-utility scalar
       subroutines, such as blessed(), reftype(), and tainted().  See

   *   "sort" is a new pragma for controlling the behaviour of sort().

   *   "Storable" gives persistence to Perl data structures by allowing
       the storage and retrieval of Perl data to and from files in a fast
       and compact binary format.  Because in effect Storable does
       serialisation of Perl data structures, with it you can also clone
       deep, hierarchical datastructures.  Storable was originally created
       by Raphael Manfredi, but it is now maintained by Abhijit Menon-Sen.
       Storable has been enhanced to understand the two new hash features,
       Unicode keys and restricted hashes.  See Storable.

   *   "Switch", by Damian Conway, has been added.  Just by saying

           use Switch;

       you have "switch" and "case" available in Perl.

           use Switch;

           switch ($val) {

                       case 1          { print "number 1" }
                       case "a"        { print "string a" }
                       case [1..10,42] { print "number in list" }
                       case (@array)   { print "number in list" }
                       case /\w+/      { print "pattern" }
                       case qr/\w+/    { print "pattern" }
                       case (%hash)    { print "entry in hash" }
                       case (\%hash)   { print "entry in hash" }
                       case (\&sub)    { print "arg to subroutine" }
                       else            { print "previous case not true" }

       See Switch.

   *   "Test::More", by Michael Schwern, is yet another framework for
       writing test scripts, more extensive than Test::Simple.  See

   *   "Test::Simple", by Michael Schwern, has basic utilities for writing
       tests.   See Test::Simple.

   *   "Text::Balanced", by Damian Conway, has been added, for extracting
       delimited text sequences from strings.

           use Text::Balanced 'extract_delimited';

           ($a, $b) = extract_delimited("'never say never', he never said", "'", '');

       $a will be "'never say never'", $b will be ', he never said'.

       In addition to extract_delimited(), there are also
       extract_bracketed(), extract_quotelike(), extract_codeblock(),
       extract_variable(), extract_tagged(), extract_multiple(),
       gen_delimited_pat(), and gen_extract_tagged().  With these, you can
       implement rather advanced parsing algorithms.  See Text::Balanced.

   *   "threads", by Arthur Bergman, is an interface to interpreter
       threads.  Interpreter threads (ithreads) is the new thread model
       introduced in Perl 5.6 but only available as an internal interface
       for extension writers (and for Win32 Perl for "fork()" emulation).
       See threads, threads::shared, and perlthrtut.

   *   "threads::shared", by Arthur Bergman, allows data sharing for
       interpreter threads.  See threads::shared.

   *   "Tie::File", by Mark-Jason Dominus, associates a Perl array with
       the lines of a file.  See Tie::File.

   *   "Tie::Memoize", by Ilya Zakharevich, provides on-demand loaded
       hashes.  See Tie::Memoize.

   *   "Tie::RefHash::Nestable", by Edward Avis, allows storing hash
       references (unlike the standard Tie::RefHash)  The module is
       contained within Tie::RefHash.  See Tie::RefHash.

   *   "Time::HiRes", by Douglas E. Wegscheid, provides high resolution
       timing (ualarm, usleep, and gettimeofday).  See Time::HiRes.

   *   "Unicode::UCD" offers a querying interface to the Unicode Character
       Database.  See Unicode::UCD.

   *   "Unicode::Collate", by SADAHIRO Tomoyuki, implements the UCA
       (Unicode Collation Algorithm) for sorting Unicode strings.  See

   *   "Unicode::Normalize", by SADAHIRO Tomoyuki, implements the various
       Unicode normalization forms.  See Unicode::Normalize.

   *   "XS::APItest", by Tim Jenness, is a test extension that exercises
       XS APIs.  Currently only "printf()" is tested: how to output
       various basic data types from XS.

   *   "XS::Typemap", by Tim Jenness, is a test extension that exercises
       XS typemaps.  Nothing gets installed, but the code is worth
       studying for extension writers.

   Updated And Improved Modules and Pragmata
   *   The following independently supported modules have been updated to
       the newest versions from CPAN: CGI, CPAN, DB_File, File::Spec,
       File::Temp, Getopt::Long, Math::BigFloat, Math::BigInt, the
       podlators bundle (Pod::Man, Pod::Text), Pod::LaTeX [561+],
       Pod::Parser, Storable, Term::ANSIColor, Test, Text-Tabs+Wrap.

   *   attributes::reftype() now works on tied arguments.

   *   AutoLoader can now be disabled with "no AutoLoader;".

   *   B::Deparse has been significantly enhanced by Robin Houston.  It
       can now 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.

   *   Carp now has better interface documentation, and the @CARP_NOT
       interface has been added to get optional control over where errors
       are reported independently of @ISA, by Ben Tilly.

   *   Class::Struct can now define the classes in compile time.

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

   *   The return value of Cwd::fastcwd() is now tainted.

   *   Data::Dumper now has an option to sort hashes.

   *   Data::Dumper now has an option to dump code references using

   *   DB_File now supports newer Berkeley DB versions, among other

   *   Devel::Peek now has an interface for the Perl memory statistics
       (this works only if you are using perl's malloc, and if you have
       compiled with debugging).

   *   The English module can now be used without the infamous performance
       hit by saying

               use English '-no_match_vars';

       (Assuming, of course, that you don't need the troublesome variables
       "$`", $&, or "$'".)  Also, introduced @LAST_MATCH_START and
       @LAST_MATCH_END English aliases for "@-" and "@+".

   *   ExtUtils::MakeMaker has been significantly cleaned up and fixed.
       The enhanced version has also been backported to earlier releases
       of Perl and submitted to CPAN so that the earlier releases can
       enjoy the fixes.

   *   The arguments of WriteMakefile() in Makefile.PL are now checked for
       sanity much more carefully than before.  This may cause new
       warnings when modules are being installed.  See ExtUtils::MakeMaker
       for more details.

   *   ExtUtils::MakeMaker now uses File::Spec internally, which hopefully
       leads to better portability.

   *   Fcntl, Socket, and Sys::Syslog have been rewritten by Nicholas
       Clark to use the new-style constant dispatch section (see
       ExtUtils::Constant).  This means that they will be more robust and
       hopefully faster.

   *   File::Find now chdir()s correctly when chasing symbolic links.

   *   File::Find now has pre- and post-processing callbacks.  It also
       correctly changes directories when chasing symbolic links.
       Callbacks (naughtily) exiting with "next;" instead of "return;" now

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

   *   The warnings issued by File::Find now belong to their own category.
       You can enable/disable them with "use/no warnings 'File::Find';".

   *   File::Glob::glob() has been renamed to File::Glob::bsd_glob()
       because the name clashes with the builtin glob().  The older name
       is still available for compatibility, but is deprecated. [561]

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

   *   IPC::Open3 now allows the use of numeric file descriptors.

   *   IO::Socket now has an atmark() method, which returns true if the
       socket is positioned at the out-of-band mark.  The method is also
       exportable as a sockatmark() function.

   *   IO::Socket::INET failed to open the specified port if the service
       name was not known.  It now correctly uses the supplied port number
       as is. [561]

   *   IO::Socket::INET has support for the ReusePort option (if your
       platform supports it).  The Reuse option now has an alias,
       ReuseAddr.  For clarity, you may want to prefer ReuseAddr.

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

   *   'use lib' now works identically to @INC.  Removing directories with
       'no lib' now works.

   *   Math::BigFloat and Math::BigInt have undergone a full rewrite by
       Tels.  They are now magnitudes faster, and they support various
       bignum libraries such as GMP and PARI as their backends.

   *   Math::Complex handles inf, NaN etc., better.

   *   Net::Ping has been considerably enhanced by Rob Brown: multihoming
       is now supported, Win32 functionality is better, there is now time
       measuring functionality (optionally high-resolution using
       Time::HiRes), and there is now "external" protocol which uses
       Net::Ping::External module which runs your external ping utility
       and parses the output.  A version of Net::Ping::External is
       available in CPAN.

       Note that some of the Net::Ping tests are disabled when running
       under the Perl distribution since one cannot assume one or more of
       the following: enabled echo port at localhost, full Internet
       connectivity, or sympathetic firewalls.  You can set the
       environment variable PERL_TEST_Net_Ping to "1" (one) before running
       the Perl test suite to enable all the Net::Ping tests.

   *   POSIX::sigaction() is now much more flexible and robust.  You can
       now install coderef handlers, 'DEFAULT', and 'IGNORE' handlers,
       installing new handlers was not atomic.

   *   In Safe, %INC is now localised in a Safe compartment so that
       use/require work.

   *   In SDBM_File on DOSish platforms, some keys went missing because of
       lack of support for files with "holes".  A workaround for the
       problem has been added.

   *   In Search::Dict one can now have a pre-processing hook for the
       lines being searched.

   *   The Shell module now has an OO interface.

   *   In Sys::Syslog there is now a failover mechanism that will go
       through alternative connection mechanisms until the message is
       successfully logged.

   *   The Test module has been significantly enhanced.

   *   Time::Local::timelocal() does not handle fractional seconds
       anymore.  The rationale is that neither does localtime(), and
       timelocal() and localtime() are supposed to be inverses of each

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

   *   The "utf8::" name space (as in the pragma) provides various Perl-
       callable functions to provide low level access to Perl's internal
       Unicode representation.  At the moment only length() has been

Utility Changes

   *   Emacs perl mode (emacs/cperl-mode.el) has been updated to version

   *   emacs/ is now much faster.

   *   "enc2xs" is a tool for people adding their own encodings to the
       Encode module.

   *   "h2ph" now supports C trigraphs.

   *   "h2xs" now produces a template README.

   *   "h2xs" now uses "Devel::PPPort" for better portability between
       different versions of Perl.

   *   "h2xs" uses the new ExtUtils::Constant module which will affect
       newly created extensions that define constants.  Since the new code
       is more correct (if you have two constants where the first one is a
       prefix of the second one, the first constant never got defined),
       less lossy (it uses integers for integer constant, as opposed to
       the old code that used floating point numbers even for integer
       constants), and slightly faster, you might want to consider
       regenerating your extension code (the new scheme makes regenerating
       easy).  h2xs now also supports C trigraphs.

   *   "libnetcfg" has been added to configure libnet.

   *   "perlbug" is now much more robust.  It also sends the bug report to, not

   *   "perlcc" has been rewritten and its user interface (that is,
       command line) is much more like that of the Unix C compiler, cc.
       (The perlbc tools has been removed.  Use "perlcc -B" instead.)
       Note that perlcc is still considered very experimental and
       unsupported. [561]

   *   "perlivp" is a new Installation Verification Procedure utility for
       running any time after installing Perl.

   *   "piconv" is an implementation of the character conversion utility
       "iconv", demonstrating the new Encode module.

   *   "pod2html" now allows specifying a cache directory.

   *   "pod2html" now produces XHTML 1.0.

   *   "pod2html" now understands POD written using different line endings
       (PC-like CRLF versus Unix-like LF versus MacClassic-like CR).

   *   "s2p" has been completely rewritten in Perl.  (It is in fact a full
       implementation of sed in Perl: you can use the sed functionality by
       using the "psed" utility.)

   *   "xsubpp" now understands POD documentation embedded in the *.xs
       files. [561]

   *   "xsubpp" now supports the OUT keyword.

New Documentation

   *   perl56delta details the changes between the 5.005 release and the
       5.6.0 release.

   *   perlclib documents the internal replacements for standard C library
       functions.  (Interesting only for extension writers and Perl core
       hackers.) [561+]

   *   perldebtut is a Perl debugging tutorial. [561+]

   *   perlebcdic contains considerations for running Perl on EBCDIC
       platforms. [561+]

   *   perlintro is a gentle introduction to Perl.

   *   perliol documents the internals of PerlIO with layers.

   *   perlmodstyle is a style guide for writing modules.

   *   perlnewmod tells about writing and submitting a new module. [561+]

   *   perlpacktut is a pack() tutorial.

   *   perlpod has been rewritten to be clearer and to record the best
       practices gathered over the years.

   *   perlpodspec is a more formal specification of the pod format,
       mainly of interest for writers of pod applications, not to people
       writing in pod.

   *   perlretut is a regular expression tutorial. [561+]

   *   perlrequick is a regular expressions quick-start guide.  Yes, much
       quicker than perlretut. [561]

   *   perltodo has been updated.

   *   perltootc has been renamed as perltooc (to not to conflict with
       perltoot in filesystems restricted to "8.3" names).

   *   perluniintro is an introduction to using Unicode in Perl.
       (perlunicode is more of a detailed reference and background

   *   perlutil explains the command line utilities packaged with the Perl
       distribution. [561+]

   The following platform-specific documents are available before the
   installation as README.platform, and after the installation as

       perlaix perlamiga perlapollo perlbeos perlbs2000
       perlce perlcygwin perldgux perldos perlepoc perlfreebsd perlhpux
       perlhurd perlirix perlmachten perlmacos perlmint perlmpeix
       perlnetware perlos2 perlos390 perlplan9 perlqnx perlsolaris
       perltru64 perluts perlvmesa perlvms perlvos perlwin32

   These documents usually detail one or more of the following subjects:
   configuring, building, testing, installing, and sometimes also using
   Perl on the said platform.

   Eastern Asian Perl users are now welcomed in their own languages: (Japanese), README.ko (Korean), (simplified
   Chinese) and (traditional Chinese), which are written in
   normal pod but encoded in EUC-JP, EUC-KR, EUC-CN and Big5.  These will
   get installed as

      perljp perlko perlcn perltw

   *   The documentation for the POSIX-BC platform is called "BS2000", to
       avoid confusion with the Perl POSIX module.

   *   The documentation for the WinCE platform is called perlce
       (README.ce in the source code kit), to avoid confusion with the
       perlwin32 documentation on 8.3-restricted filesystems.

Performance Enhancements

   *   map() could get pathologically slow when the result list it
       generates is larger than the source list.  The performance has been
       improved for common scenarios. [561]

   *   sort() is also fully reentrant, in the sense that the sort function
       can itself call sort().  This did not work reliably in previous
       releases. [561]

   *   sort() has been changed to use primarily mergesort internally as
       opposed to the earlier quicksort.  For very small lists this may
       result in slightly slower sorting times, but in general the speedup
       should be at least 20%.  Additional bonuses are that the worst case
       behaviour of sort() is now better (in computer science terms it now
       runs in time O(N log N), as opposed to quicksort's Theta(N**2)
       worst-case run time behaviour), and that sort() is now stable
       (meaning that elements with identical keys will stay ordered as
       they were before the sort).  See the "sort" pragma for information.

       The story in more detail: suppose you want to serve yourself a
       little slice of Pi.

           @digits = ( 3,1,4,1,5,9 );

       A numerical sort of the digits will yield (1,1,3,4,5,9), as
       expected.  Which 1 comes first is hard to know, since one 1 looks
       pretty much like any other.  You can regard this as totally
       trivial, or somewhat profound.  However, if you just want to sort
       the even digits ahead of the odd ones, then what will

           sort { ($a % 2) <=> ($b % 2) } @digits;

       yield?  The only even digit, 4, will come first.  But how about the
       odd numbers, which all compare equal?  With the quicksort algorithm
       used to implement Perl 5.6 and earlier, the order of ties is left
       up to the sort.  So, as you add more and more digits of Pi, the
       order in which the sorted even and odd digits appear will change.
       and, for sufficiently large slices of Pi, the quicksort algorithm
       in Perl 5.8 won't return the same results even if reinvoked with
       the same input.  The justification for this rests with quicksort's
       worst case behavior.  If you run

          sort { $a <=> $b } ( 1 .. $N , 1 .. $N );

       (something you might approximate if you wanted to merge two sorted
       arrays using sort), doubling $N doesn't just double the quicksort
       time, it quadruples it.  Quicksort has a worst case run time that
       can grow like N**2, so-called quadratic behaviour, and it can
       happen on patterns that may well arise in normal use.  You won't
       notice this for small arrays, but you will notice it with larger
       arrays, and you may not live long enough for the sort to complete
       on arrays of a million elements.  So the 5.8 quicksort scrambles
       large arrays before sorting them, as a statistical defence against
       quadratic behaviour.  But that means if you sort the same large
       array twice, ties may be broken in different ways.

       Because of the unpredictability of tie-breaking order, and the
       quadratic worst-case behaviour, quicksort was almost replaced
       completely with a stable mergesort.  Stable means that ties are
       broken to preserve the original order of appearance in the input
       array.  So

           sort { ($a % 2) <=> ($b % 2) } (3,1,4,1,5,9);

       will yield (4,3,1,1,5,9), guaranteed.  The even and odd numbers
       appear in the output in the same order they appeared in the input.
       Mergesort has worst case O(N log N) behaviour, the best value
       attainable.  And, ironically, this mergesort does particularly well
       where quicksort goes quadratic:  mergesort sorts (1..$N, 1..$N) in
       O(N) time.  But quicksort was rescued at the last moment because it
       is faster than mergesort on certain inputs and platforms.  For
       example, if you really don't care about the order of even and odd
       digits, quicksort will run in O(N) time; it's very good at sorting
       many repetitions of a small number of distinct elements.  The
       quicksort divide and conquer strategy works well on platforms with
       relatively small, very fast, caches.  Eventually, the problem gets
       whittled down to one that fits in the cache, from which point it
       benefits from the increased memory speed.

       Quicksort was rescued by implementing a sort pragma to control
       aspects of the sort.  The stable subpragma forces stable behaviour,
       regardless of algorithm.  The _quicksort and _mergesort subpragmas
       are heavy-handed ways to select the underlying implementation.  The
       leading "_" is a reminder that these subpragmas may not survive
       beyond 5.8.  More appropriate mechanisms for selecting the
       implementation exist, but they wouldn't have arrived in time to
       save quicksort.

   *   Hashes now use Bob Jenkins "One-at-a-Time" hashing key algorithm ( ).  This algorithm is
       reasonably fast while producing a much better spread of values than
       the old hashing algorithm (originally by Chris Torek, later tweaked
       by Ilya Zakharevich).  Hash values output from the algorithm on a
       hash of all 3-char printable ASCII keys comes much closer to
       passing the DIEHARD random number generation tests.  According to
       perlbench, this change has not affected the overall speed of Perl.

   *   unshift() should now be noticeably faster.

Installation and Configuration Improvements

   Generic Improvements
   *   INSTALL now explains how you can configure Perl to use 64-bit
       integers even on non-64-bit platforms.

   * policy change: if you are reusing a file (see
       INSTALL) and you use Configure -Dprefix=/foo/bar and in the old
       Policy $prefix eq $siteprefix and $prefix eq $vendorprefix, all of
       them will now be changed to the new prefix, /foo/bar.  (Previously
       only $prefix changed.)  If you do not like this new behaviour,
       specify prefix, siteprefix, and vendorprefix explicitly.

   *   A new optional location for Perl libraries, otherlibdirs, is
       available.  It can be used for example for vendor add-ons without
       disturbing Perl's own library directories.

   *   In many platforms, the vendor-supplied 'cc' is too stripped-down to
       build Perl (basically, 'cc' doesn't do ANSI C).  If this seems to
       be the case and 'cc' does not seem to be the GNU C compiler 'gcc',
       an automatic attempt is made to find and use 'gcc' instead.

   *   gcc needs to closely track the operating system release to avoid
       build problems. If Configure finds that gcc was built for a
       different operating system release than is running, it now gives a
       clearly visible warning that there may be trouble ahead.

   *   Since Perl 5.8 is not binary-compatible with previous releases of
       Perl, Configure no longer suggests including the 5.005 modules in

   *   Configure "-S" can now run non-interactively. [561]

   *   Configure support for pdp11-style memory models has been removed
       due to obsolescence. [561]

   *   configure.gnu now works with options with whitespace in them.

   *   installperl now outputs everything to STDERR.

   *   Because PerlIO is now the default on most platforms, "-perlio"
       doesn't get appended to the $Config{archname} (also known as $^O)
       anymore.  Instead, if you explicitly choose not to use perlio
       (Configure command line option -Uuseperlio), you will get "-stdio"

   *   Another change related to the architecture name is that "-64all"
       (-Duse64bitall, or "maximally 64-bit") is appended only if your
       pointers are 64 bits wide.  (To be exact, the use64bitall is

   *   In AFS installations, one can configure the root of the AFS to be
       somewhere else than the default /afs by using the Configure
       parameter "-Dafsroot=/some/where/else".

   *   APPLLIB_EXP, a lesser-known configuration-time definition, has been
       documented.  It can be used to prepend site-specific directories to
       Perl's default search path (@INC); see INSTALL for information.

   *   The version of Berkeley DB used when the Perl (and, presumably, the
       DB_File extension) was built is now available as
       @Config{qw(db_version_major db_version_minor db_version_patch)}
       DB_VERSION_PATCH_CFG" from C.

   *   Building Berkeley DB3 for compatibility modes for DB, NDBM, and
       ODBM has been documented in INSTALL.

   *   If you have CPAN access (either network or a local copy such as a
       CD-ROM) you can during specify extra modules to Configure to build
       and install with Perl using the -Dextras=...  option.  See INSTALL
       for more details.

   *   In addition to config.over, a new override file, config.arch, is
       available.  This file is supposed to be used by hints file writers
       for architecture-wide changes (as opposed to config.over which is
       for site-wide changes).

   *   If your file system supports symbolic links, you can build Perl
       outside of the source directory by

               mkdir perl/build/directory
               cd perl/build/directory
               sh /path/to/perl/source/Configure -Dmksymlinks ...

       This will create in perl/build/directory a tree of symbolic links
       pointing to files in /path/to/perl/source.  The original files are
       left unaffected.  After Configure has finished, you can just say

               make all test

       and Perl will be built and tested, all in perl/build/directory.

   *   For Perl developers, several new make targets for profiling and
       debugging have been added; see perlhack.

       *       Use of the gprof tool to profile Perl has been documented
               in perlhack.  There is a make target called "perl.gprof"
               for generating a gprofiled Perl executable.

       *       If you have GCC 3, there is a make target called
               "perl.gcov" for creating a gcoved Perl executable for
               coverage analysis.  See perlhack.

       *       If you are on IRIX or Tru64 platforms, new
               profiling/debugging options have been added; see perlhack
               for more information about pixie and Third Degree.

   *   Guidelines of how to construct minimal Perl installations have been
       added to INSTALL.

   *   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

       Note that the 5.005 threads are unsupported and deprecated: if you
       have code written for the old threads you should migrate it to the
       new ithreads model.

   *   The Gconvert macro ($Config{d_Gconvert}) used by perl for
       stringifying floating-point numbers is now more picky about using
       sprintf %.*g rules for the conversion.  Some platforms that used to
       use gcvt may now resort to the slower sprintf.

   *   The obsolete method of making a special (e.g., debugging) flavor of
       perl by saying

               make LIBPERL=libperld.a

       has been removed. Use -DDEBUGGING instead.

   New Or Improved Platforms
   For the list of platforms known to support Perl, see "Supported
   Platforms" in perlport.

   *   AIX dynamic loading should be now better supported.

   *   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 ( ) is a new platform.

   *   BeOS has been reclaimed.

   *   The DG/UX platform now supports 5.005-style threads.  See perldgux.

   *   The DYNIX/ptx platform (also known as dynixptx) is supported at or
       near osvers 4.5.2.

   *   EBCDIC platforms (z/OS (also known as OS/390), POSIX-BC, and
       VM/ESA) have been regained.  Many test suite tests still fail and
       the co-existence of Unicode and EBCDIC isn't quite settled, but the
       situation is much better than with Perl 5.6.  See perlos390,
       perlbs2000 (for POSIX-BC), and perlvmesa for more information.
       (Note: support for VM/ESA was removed in Perl v5.18.0. The relevant
       information was in README.vmesa)

   *   Building perl with -Duseithreads or -Duse5005threads now works
       under HP-UX 10.20 (previously it only worked under 10.30 or later).
       You will need a thread library package installed. See README.hpux.

   *   Mac OS Classic is now supported in the mainstream source package
       (MacPerl has of course been available since perl 5.004 but now the
       source code bases of standard Perl and MacPerl have been
       synchronised) [561]

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

   *   NCR MP-RAS is now supported. [561]

   *   All the NetBSD specific patches (except for the installation
       specific ones) have been merged back to the main distribution.

   *   NetWare from Novell is now supported.  See perlnetware.

   *   NonStop-UX is now supported. [561]

   *   NEC SUPER-UX is now supported.

   *   All the OpenBSD specific patches (except for the installation
       specific ones) have been merged back to the main distribution.

   *   Perl has been tested with the GNU pth userlevel thread package ( ).  All thread tests of
       Perl now work, but not without adding some yield()s to the tests,
       so while pth (and other userlevel thread implementations) can be
       considered to be "working" with Perl ithreads, keep in mind the
       possible non-preemptability of the underlying thread

   *   Stratus VOS is now supported using Perl's native build method
       (Configure).  This is the recommended method to build Perl on VOS.
       The older methods, which build miniperl, are still available.  See
       perlvos. [561+]

   *   The Amdahl UTS Unix mainframe platform is now supported. [561]

   *   WinCE is now supported.  See perlce.

   *   z/OS (formerly known as OS/390, formerly known as MVS OE) now has
       support for dynamic loading.  This is not selected by default,
       however, you must specify -Dusedl in the arguments of Configure.

Selected Bug Fixes

   Numerous memory leaks and uninitialized memory accesses have been
   hunted down.  Most importantly, anonymous subs used to leak quite a
   bit. [561]

   *   The autouse pragma didn't work for Multi::Part::Function::Names.

   *   caller() could cause core dumps in certain situations.  Carp was
       sometimes affected by this problem.  In particular, caller() now
       returns a subroutine name of "(unknown)" for subroutines that have
       been removed from the symbol table.

   *   chop(@list) in list context returned the characters chopped in
       reverse order.  This has been reversed to be in the right order.

   *   Configure no longer includes the DBM libraries (dbm, gdbm, db,
       ndbm) when building the Perl binary.  The only exception to this is
       SunOS 4.x, which needs them. [561]

   *   The behaviour of non-decimal but numeric string constants 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's using the operating system libraries in a
       situation where the result of the string to number conversion is
       undefined: now Perl consistently handles such strings as zero in
       numeric contexts.

   *   Several debugger fixes: exit code now reflects the script exit
       code, condition "0" now treated correctly, the "d" command now
       checks line number, $. no longer gets corrupted, and all debugger
       output now goes correctly to the socket if RemotePort is set. [561]

   *   The debugger ( has been modified to present a more
       consistent commands interface, via (CommandSet=580).  perl5db.t was
       also added to test the changes, and as a placeholder for further

       See perldebug.

   *   The debugger has a new "dumpDepth" option to control the maximum
       depth to which nested structures are dumped.  The "x" command has
       been extended so that "x N EXPR" dumps out the value of EXPR to a
       depth of at most N levels.

   *   The debugger can now show lexical variables if you have the CPAN
       module PadWalker installed.

   *   The order of DESTROYs has been made more predictable.

   *   Perl 5.6.0 could emit spurious warnings about redefinition of
       dl_error() when statically building extensions into perl.  This has
       been corrected. [561]

   *   dprofpp -R didn't work.

   *   *foo{FORMAT} now works.

   *   Infinity is now recognized as a number.

   *   UNIVERSAL::isa no longer caches methods incorrectly.  (This broke
       the Tk extension with 5.6.0.) [561]

   *   Lexicals I: lexicals outside an eval "" weren't resolved correctly
       inside a subroutine definition inside the eval "" if they were not
       already referenced in the top level of the eval""ed code.

   *   Lexicals II: lexicals leaked at file scope into subroutines that
       were declared before the lexicals.

   *   Lexical warnings now propagating correctly between scopes and into
       "eval "..."".

   *   "use warnings qw(FATAL all)" did not work as intended.  This has
       been corrected. [561]

   *   warnings::enabled() now reports the state of $^W correctly if the
       caller isn't using lexical warnings. [561]

   *   Line renumbering with eval and "#line" now works. [561]

   *   Fixed numerous memory leaks, especially in eval "".

   *   Localised tied variables no longer leak memory

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


           # Used to leak memory every time local() was called;
           # in a loop, this added up.
           local($tied_hash{Foo}) = 1;

   *   Localised hash elements (and %ENV) are correctly unlocalised to not
       exist, if they didn't before they were localised.

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


           # Nothing has set the FOO element so far

           { local $tied_hash{FOO} = 'Bar' }

           # This used to print, but not now.
           print "exists!\n" if exists $tied_hash{FOO};

       As a side effect of this fix, tied hash interfaces must define the
       EXISTS and DELETE methods.

   *   mkdir() now ignores trailing slashes in the directory name, as
       mandated by POSIX.

   *   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.

   *   Modulus of unsigned numbers now works (4063328477 % 65535 used to
       return 27406, instead of 27047). [561]

   *   Some "not a number" warnings introduced in 5.6.0 eliminated to be
       more compatible with 5.005.  Infinity is now recognised as a
       number. [561]

   *   Numeric conversions did not recognize changes in the string value
       properly in certain circumstances. [561]

   *   Attributes (such as :shared) didn't work with our().

   *   our() variables will not cause bogus "Variable will not stay
       shared" warnings. [561]

   *   "our" variables of the same name declared in two sibling blocks
       resulted in bogus warnings about "redeclaration" of the variables.
       The problem has been corrected. [561]

   *   pack "Z" now correctly terminates the string with "\0".

   *   Fix password routines which in some shadow password platforms (e.g.
       HP-UX) caused getpwent() to return every other entry.

   *   The PERL5OPT environment variable (for passing command line
       arguments to Perl) didn't work for more than a single group of
       options. [561]

   *   PERL5OPT with embedded spaces didn't work.

   *   printf() no longer resets the numeric locale to "C".

   *   "qw(a\\b)" now parses correctly as 'a\\b': that is, as three
       characters, not four. [561]

   *   pos() did not return the correct value within s///ge in earlier
       versions.  This is now handled correctly. [561]

   *   Printing quads (64-bit integers) with printf/sprintf now works
       without the q L ll prefixes (assuming you are on a quad-capable

   *   Regular expressions on references and overloaded scalars now work.

   *   Right-hand side magic (GMAGIC) could in many cases such as string
       concatenation be invoked too many times.

   *   scalar() now forces scalar context even when used in void context.

   *   SOCKS support is now much more robust.

   *   sort() arguments are now compiled in the right wantarray context
       (they were accidentally using the context of the sort() itself).
       The comparison block is now run in scalar context, and the
       arguments to be sorted are always provided list context. [561]

   *   Changed the POSIX character class "[[:space:]]" to include the
       (very rarely used) vertical tab character.  Added a new POSIX-ish
       character class "[[:blank:]]" which stands for horizontal
       whitespace (currently, the space and the tab).

   *   The tainting behaviour of sprintf() has been rationalized.  It does
       not taint the result of floating point formats anymore, making the
       behaviour consistent with that of string interpolation. [561]

   *   Some cases of inconsistent taint propagation (such as within hash
       values) have been fixed.

   *   The RE engine found in Perl 5.6.0 accidentally pessimised certain
       kinds of simple pattern matches.  These are now handled better.

   *   Regular expression debug output (whether through "use re 'debug'"
       or via "-Dr") now looks better. [561]

   *   Multi-line matches like ""a\nxb\n" =~ /(?!\A)x/m" were flawed.  The
       bug has been fixed. [561]

   *   Use of $& could trigger a core dump under some situations.  This is
       now avoided. [561]

   *   The regular expression captured submatches ($1, $2, ...) are now
       more consistently unset if the match fails, instead of leaving
       false data lying around in them. [561]

   *   readline() on files opened in "slurp" mode could return an extra ""
       (blank line) at the end in certain situations.  This has been
       corrected. [561]

   *   Autovivification of symbolic references of special variables
       described in perlvar (as in "${$num}") was accidentally disabled.
       This works again now. [561]

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

   *   $AUTOLOAD, sort(), lock(), and spawning subprocesses in multiple
       threads simultaneously are now thread-safe.

   *   Tie::Array's SPLICE method was broken.

   *   Allow a read-only string on the left-hand side of a non-modifying

   *   If "STDERR" is tied, warnings caused by "warn" and "die" now
       correctly pass to it.

   *   Several Unicode fixes.

       *       BOMs (byte order marks) at the beginning of Perl files
               (scripts, modules) should now be transparently skipped.
               UTF-16 and UCS-2 encoded Perl files should now be read

       *       The character tables have been updated to Unicode 3.2.0.

       *       Comparing with utf8 data does not magically upgrade
               non-utf8 data into utf8.  (This was a problem for example
               if you were mixing data from I/O and Unicode data: your
               output might have got magically encoded as UTF-8.)

       *       Generating illegal Unicode code points such as U+FFFE, or
               the UTF-16 surrogates, now also generates an optional

       *       "IsAlnum", "IsAlpha", and "IsWord" now match titlecase.

       *       Concatenation with the "." operator or via variable
               interpolation, "eq", "substr", "reverse", "quotemeta", the
               "x" operator, substitution with "s///", single-quoted
               UTF-8, should now work.

       *       The "tr///" operator now works.  Note that the "tr///CU"
               functionality has been removed (but see pack('U0', ...)).

       *       "eval "v200"" now works.

       *       Perl 5.6.0 parsed m/\x{ab}/ incorrectly, leading to
               spurious warnings.  This has been corrected. [561]

       *       Zero entries were missing from the Unicode classes such as

   *   Large unsigned numbers (those above 2**31) could sometimes lose
       their unsignedness, causing bogus results in arithmetic operations.

   *   The Perl parser has been stress tested using both random input and
       Markov chain input and the few found crashes and lockups have been

   Platform Specific Changes and Fixes
   *   BSDI 4.*

       Perl now works on post-4.0 BSD/OSes.

   *   All BSDs

       Setting $0 now works (as much as possible; see perlvar for

   *   Cygwin

       Numerous updates; currently synchronised with Cygwin 1.3.10.

   *   Previously DYNIX/ptx had problems in its Configure probe for non-
       blocking I/O.

   *   EPOC

       EPOC now better supported.  See README.epoc. [561]

   *   FreeBSD 3.*

       Perl now works on post-3.0 FreeBSDs.

   *   HP-UX

       README.hpux updated; "Configure -Duse64bitall" now works; now uses
       HP-UX malloc instead of Perl malloc.

   *   IRIX

       Numerous compilation flag and hint enhancements; accidental mixing
       of 32-bit and 64-bit libraries (a doomed attempt) made much harder.

   *   Linux

       *       Long doubles should now work (see INSTALL). [561]

       *       Linux previously had problems related to sockaddrlen when
               using accept(), recvfrom() (in Perl: recv()),
               getpeername(), and getsockname().

   *   Mac OS Classic

       Compilation of the standard Perl distribution in Mac OS Classic
       should now work if you have the Metrowerks development environment
       and the missing Mac-specific toolkit bits.  Contact the macperl
       mailing list for details.

   *   MPE/iX

       MPE/iX update after Perl 5.6.0.  See README.mpeix. [561]

   *   NetBSD/threads: try installing the GNU pth (should be in the
       packages collection, or, and
       Configure with -Duseithreads.

   *   NetBSD/sparc

       Perl now works on NetBSD/sparc.

   *   OS/2

       Now works with usethreads (see INSTALL). [561]

   *   Solaris

       64-bitness using the Sun Workshop compiler now works.

   *   Stratus VOS

       The native build method requires at least VOS Release 14.5.0 and
       GNU C++/GNU Tools 2.0.1 or later.  The Perl pack function now maps
       overflowed values to +infinity and underflowed values to -infinity.

   *   Tru64 (aka Digital UNIX, aka DEC OSF/1)

       The operating system version letter now recorded in
       $Config{osvers}.  Allow compiling with gcc (previously explicitly
       forbidden).  Compiling with gcc still not recommended because buggy
       code results, even with gcc 2.95.2.

   *   Unicos

       Fixed various alignment problems that lead into core dumps either
       during build or later; no longer dies on math errors at runtime;
       now using full quad integers (64 bits), previously was using only
       46 bit integers for speed.

   *   VMS

       See "Socket Extension Dynamic in VMS" and "IEEE-format Floating
       Point Default on OpenVMS Alpha" for important changes not otherwise
       listed here.

       chdir() now works better despite a CRT bug; now works with
       MULTIPLICITY (see INSTALL); now works with Perl's malloc.

       The tainting of %ENV elements via "keys" or "values" was previously
       unimplemented.  It now works as documented.

       The "waitpid" emulation has been improved.  The worst bug (now
       fixed) was that a pid of -1 would cause a wildcard search of all
       processes on the system.

       POSIX-style signals are now emulated much better on VMS versions
       prior to 7.0.

       The "system" function and backticks operator have improved
       functionality and better error handling. [561]

       File access tests now use current process privileges rather than
       the user's default privileges, which could sometimes result in a
       mismatch between reported access and actual access.  This
       improvement is only available on VMS v6.0 and later.

       There is a new "kill" implementation based on "sys$sigprc" that
       allows older VMS systems (pre-7.0) to use "kill" to send signals
       rather than simply force exit.  This implementation also allows
       later systems to call "kill" from within a signal handler.

       Iterative logical name translations are now limited to 10
       iterations in imitation of SHOW LOGICAL and other OpenVMS

   *   Windows

       *       Signal handling now works better than it used to.  It is
               now implemented using a Windows message loop, and is
               therefore less prone to random crashes.

       *       fork() emulation is now more robust, but still continues to
               have a few esoteric bugs and caveats.  See perlfork for
               details. [561+]

       *       A failed (pseudo)fork now returns undef and sets errno to
               EAGAIN. [561]

       *       The following modules now work on Windows:

                   ExtUtils::Embed         [561]

       *       IO::File::new_tmpfile() is no longer limited to 32767
               invocations per-process.

       *       Better chdir() return value for a non-existent directory.

       *       Compiling perl using the 64-bit Platform SDK tools is now

       *       The Win32::SetChildShowWindow() builtin can be used to
               control the visibility of windows created by child
               processes.  See Win32 for details.

       *       Non-blocking waits for child processes (or pseudo-
               processes) are supported via "waitpid($pid,

       *       The behavior of system() with multiple arguments has been
               rationalized.  Each unquoted argument will be automatically
               quoted to protect whitespace, and any existing whitespace
               in the arguments will be preserved.  This improves the
               portability of system(@args) by avoiding the need for
               Windows "cmd" shell specific quoting in perl programs.

               Note that this means that some scripts that may have relied
               on earlier buggy behavior may no longer work correctly.
               For example, "system("nmake /nologo", @args)" will now
               attempt to run the file "nmake /nologo" and will fail when
               such a file isn't found.  On the other hand, perl will now
               execute code such as "system("c:/Program
               Files/MyApp/foo.exe", @args)" correctly.

       *       The perl header files no longer suppress common warnings
               from the Microsoft Visual C++ compiler.  This means that
               additional warnings may now show up when compiling XS code.

       *       Borland C++ v5.5 is now a supported compiler that can build
               Perl.  However, the generated binaries continue to be
               incompatible with those generated by the other supported
               compilers (GCC and Visual C++). [561]

       *       Duping socket handles with open(F, ">&MYSOCK") now works
               under Windows 9x.  [561]

       *       Current directory entries in %ENV are now correctly
               propagated to child processes. [561]

       *       New %ENV entries now propagate to subprocesses. [561]

       *       Win32::GetCwd() correctly returns C:\ instead of C: when at
               the drive root.  Other bugs in chdir() and Cwd::cwd() have
               also been fixed. [561]

       *       The makefiles now default to the features enabled in
               ActiveState ActivePerl (a popular Win32 binary
               distribution). [561]

       *       HTML files will now be installed in c:\perl\html instead of

       *       REG_EXPAND_SZ keys are now allowed in registry settings
               used by perl. [561]

       *       Can now send() from all threads, not just the first one.

       *       ExtUtils::MakeMaker now uses $ENV{LIB} to search for
               libraries. [561]

       *       Less stack reserved per thread so that more threads can run
               concurrently. (Still 16M per thread.) [561]

       *       "File::Spec->tmpdir()" now prefers C:/temp over /tmp (works
               better when perl is running as service).

       *       Better UNC path handling under ithreads. [561]

       *       wait(), waitpid(), and backticks now return the correct
               exit status under Windows 9x. [561]

       *       A socket handle leak in accept() has been fixed. [561]

New or Changed Diagnostics

   Please see perldiag for more details.

   *   Ambiguous range in the transliteration operator (like a-z-9) now
       gives a warning.

   *   chdir("") and chdir(undef) now give a deprecation warning because
       they cause a possible unintentional chdir to the home directory.
       Say chdir() if you really mean that.

   *   Two new debugging options have been added: if you have compiled
       your Perl with debugging, you can use the -DT [561] and -DR options
       to trace tokenising and to add reference counts to displaying
       variables, respectively.

   *   The lexical warnings category "deprecated" is no longer a sub-
       category of the "syntax" category. It is now a top-level category
       in its own right.

   *   Unadorned dump() will now give a warning suggesting to use explicit
       CORE::dump() if that's what really is meant.

   *   The "Unrecognized escape" warning has been extended to include
       "\8", "\9", and "\_".  There is no need to escape any of the "\w"

   *   All regular expression compilation error messages are now hopefully
       easier to understand both because the error message now comes
       before the failed regex and because the point of failure is now
       clearly marked by a "<-- HERE" marker.

   *   Various I/O (and socket) functions like binmode(), close(), and so
       forth now more consistently warn if they are used illogically
       either on a yet unopened or on an already closed filehandle (or

   *   Using lstat() on a filehandle now gives a warning.  (It's a non-
       sensical thing to do.)

   *   The "-M" and "-m" options now warn if you didn't supply the module

   *   If you in "use" specify a required minimum version, modules
       matching the name and but not defining a $VERSION will cause a
       fatal failure.

   *   Using negative offset for vec() in lvalue context is now a warnable

   *   Odd number of arguments to overload::constant now elicits a

   *   Odd number of elements in anonymous hash now elicits a warning.

   *   The various "opened only for", "on closed", "never opened" warnings
       drop the "main::" prefix for filehandles in the "main" package, for
       example "STDIN" instead of "main::STDIN".

   *   Subroutine prototypes are now checked more carefully, you may get
       warnings for example if you have used non-prototype characters.

   *   If an attempt to use a (non-blessed) reference as an array index is
       made, a warning is given.

   *   "push @a;" and "unshift @a;" (with no values to push or unshift)
       now give a warning.  This may be a problem for generated and
       eval'ed code.

   *   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.

   *   pack "P" format now demands an explicit size.

   *   unpack "w" now warns of unterminated compressed integers.

   *   Warnings relating to the use of PerlIO have been added.

   *   Certain regex modifiers such as "(?o)" make sense only if applied
       to the entire regex.  You will get an optional warning if you try
       to do otherwise.

   *   Variable length lookbehind has not yet been implemented, trying to
       use it will tell that.

   *   Using arrays or hashes as references (e.g. "%foo->{bar}" has been
       deprecated for a while.  Now you will get an optional warning.

   *   Warnings relating to the use of the new restricted hashes feature
       have been added.

   *   Self-ties of arrays and hashes are not supported and fatal errors
       will happen even at an attempt to do so.

   *   Using "sort" in scalar context now issues an optional warning.
       This didn't do anything useful, as the sort was not performed.

   *   Using the /g modifier in split() is meaningless and will cause a

   *   Using splice() past the end of an array now causes a warning.

   *   Malformed Unicode encodings (UTF-8 and UTF-16) cause a lot of
       warnings, as does trying to use UTF-16 surrogates (which are

   *   Trying to use Unicode characters on an I/O stream without marking
       the stream's encoding (using open() or binmode()) will cause "Wide
       character" warnings.

   *   Use of v-strings in use/require causes a (backward) portability

   *   Warnings relating to the use interpreter threads and their shared
       data have been added.

Changed Internals

   *   PerlIO is now the default.

   *   perlapi.pod (a companion to perlguts) now attempts to document the
       internal API.

   *   You can now build a really minimal perl called microperl.  Building
       microperl does not require even running Configure; "make -f
       Makefile.micro" should be enough.  Beware: microperl makes many
       assumptions, some of which may be too bold; the resulting
       executable may crash or otherwise misbehave in wondrous ways.  For
       careful hackers only.

   *   Added rsignal(), whichsig(), do_join(), op_clear, op_null,
       ptr_table_clear(), ptr_table_free(), sv_setref_uv(), and several
       UTF-8 interfaces to the publicised API.  For the full list of the
       available APIs see perlapi.

   *   Made possible to propagate customised exceptions via croak()ing.

   *   Now xsubs can have attributes just like subs.  (Well, at least the
       built-in attributes.)

   *   dTHR and djSP have been obsoleted; the former removed (because it's
       a no-op) and the latter replaced with dSP.

   *   PERL_OBJECT has been completely removed.

   *   The MAGIC constants (e.g. 'P') have been macrofied (e.g.
       "PERL_MAGIC_TIED") for better source code readability and

   *   The regex compiler now maintains a structure that identifies 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 information.

   *   The C code has been made much more "gcc -Wall" clean.  Some warning
       messages still remain in some platforms, so if you are compiling
       with gcc you may see some warnings about dubious practices.  The
       warnings are being worked on.

   *   perly.c, sv.c, and sv.h have now been extensively commented.

   *   Documentation on how to use the Perl source repository has been
       added to Porting/repository.pod.

   *   There are now several profiling make targets.

Security Vulnerability Closed [561]

   (This change was already made in 5.7.0 but bears repeating here.)
   (5.7.0 came out before 5.6.1: the development branch 5.7 released
   earlier than the maintenance branch 5.6)

   A potential security vulnerability in the optional suidperl component
   of Perl was identified in August 2000.  suidperl is neither built nor
   installed by default.  As of November 2001 the only known vulnerable
   platform is Linux, most likely all Linux distributions.  CERT and
   various vendors and distributors have been alerted about the
   vulnerability.  See for
   more information.

   The problem was caused by Perl trying to report a suspected security
   exploit attempt using an external program, /bin/mail.  On Linux
   platforms the /bin/mail program had an undocumented feature which when
   combined with suidperl gave access to a root shell, resulting in a
   serious compromise instead of reporting the exploit attempt.  If you
   don't have /bin/mail, or if you have 'safe setuid scripts', or if
   suidperl is not installed, you are safe.

   The exploit attempt reporting feature has been completely removed from
   Perl 5.8.0 (and the maintenance release 5.6.1, and it was removed also
   from all the Perl 5.7 releases), so that particular vulnerability isn't
   there anymore.  However, further security vulnerabilities are,
   unfortunately, always possible.  The suidperl functionality is most
   probably going to be removed in Perl 5.10.  In any case, suidperl
   should only be used by security experts who know exactly what they are
   doing and why they are using suidperl instead of some other solution
   such as sudo ( see ).

New Tests

   Several new tests have been added, especially for the lib and ext
   subsections.  There are now about 69 000 individual tests (spread over
   about 700 test scripts), in the regression suite (5.6.1 has about 11
   700 tests, in 258 test scripts)  The exact numbers depend on the
   platform and Perl configuration used.  Many of the new tests are of
   course introduced by the new modules, but still in general Perl is now
   more thoroughly tested.

   Because of the large number of tests, running the regression suite will
   take considerably longer time than it used to: expect the suite to take
   up to 4-5 times longer to run than in perl 5.6.  On a really fast
   machine you can hope to finish the suite in about 6-8 minutes
   (wallclock time).

   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

   The Compiler Suite Is Still Very Experimental
   The compiler suite is slowly getting better but it continues to be
   highly experimental.  Use in production environments is discouraged.

   Localising Tied Arrays and Hashes Is Broken
       local %tied_array;

   doesn't work as one would expect: the old value is restored
   incorrectly.  This will be changed in a future release, but we don't
   know yet what the new semantics will exactly be.  In any case, the
   change will break existing code that relies on the current (ill-
   defined) semantics, so just avoid doing this in general.

   Building Extensions Can Fail Because Of Largefiles
   Some extensions like mod_perl are known to have issues with
   `largefiles', a change brought by Perl 5.6.0 in which file offsets
   default to 64 bits wide, where supported.  Modules may fail to compile
   at all, or they may compile and work incorrectly.  Currently, there is
   no good solution for the problem, but Configure now provides
   appropriate non-largefile ccflags, ldflags, libswanted, and libs in the
   %Config hash (e.g., $Config{ccflags_nolargefiles}) so the extensions
   that are having problems can try configuring themselves without the
   largefileness.  This is admittedly not a clean solution, and the
   solution may not even work at all.  One potential failure is whether
   one can (or, if one can, whether it's a good idea to) link together at
   all binaries with different ideas about file offsets; all this is

   Modifying $_ Inside for(..)
      for (1..5) { $_++ }

   works without complaint.  It shouldn't.  (You should be able to modify
   only lvalue elements inside the loops.)  You can see the correct
   behaviour by replacing the 1..5 with 1, 2, 3, 4, 5.

   mod_perl 1.26 Doesn't Build With Threaded Perl
   Use mod_perl 1.27 or higher.

   lib/ftmp-security tests warn 'system possibly insecure'
   Don't panic.  Read the 'make test' section of INSTALL instead.

   libwww-perl (LWP) fails base/date #51
   Use libwww-perl 5.65 or later.

   PDL failing some tests
   Use PDL 2.3.4 or later.

   You may get errors like 'Undefined symbol "Perl_get_sv"' or "can't
   resolve symbol 'Perl_get_sv'", or the symbol may be "Perl_sv_2pv".
   This probably means that you are trying to use an older shared Perl
   library (or extensions linked with such) with Perl 5.8.0 executable.
   Perl used to have such a subroutine, but that is no more the case.
   Check your shared library path, and any shared Perl libraries in those

   Sometimes this problem may also indicate a partial Perl 5.8.0
   installation, see "Mac OS X dyld undefined symbols" for an example and
   how to deal with it.

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

   A change to self-tying of globs has caused them to be recursively
   referenced (see: "Two-Phased Garbage Collection" in perlobj).  You will
   now need an explicit untie to destroy a self-tied glob.  This behaviour
   may be fixed at a later date.

   Self-tying of scalars and IO thingies works.

   If this test fails, it indicates that your libc (C library) is not
   threadsafe.  This particular test stress tests the localtime() call to
   find out whether it is threadsafe.  See perlthrtut for more

   Failure of Thread (5.005-style) tests
   Note that support for 5.005-style threading is deprecated, experimental
   and practically unsupported.  In 5.10, it is expected to be removed.
   You should migrate your code to ithreads.

   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.

    ../ext/B/t/xref.t                    255 65280    14   12  85.71%  3-14
    ../ext/List/Util/t/first.t           255 65280     7    4  57.14%  2 5-7
    ../lib/English.t                       2   512    54    2   3.70%  2-3
    ../lib/FileCache.t                                 5    1  20.00%  5
    ../lib/Filter/Simple/t/data.t                      6    3  50.00%  1-3
    ../lib/Filter/Simple/t/filter_only.                9    3  33.33%  1-2 5
    ../lib/Math/BigInt/t/bare_mbf.t                 1627    4   0.25%  8 11 1626-1627
    ../lib/Math/BigInt/t/bigfltpm.t                 1629    4   0.25%  10 13 1628-
    ../lib/Math/BigInt/t/sub_mbf.t                  1633    4   0.24%  8 11 1632-1633
    ../lib/Math/BigInt/t/with_sub.t                 1628    4   0.25%  9 12 1627-1628
    ../lib/Tie/File/t/31_autodefer.t     255 65280    65   32  49.23%  34-65
    ../lib/autouse.t                                  10    1  10.00%  4
    op/flip.t                                         15    1   6.67%  15

   These failures are unlikely to get fixed as 5.005-style threads are
   considered fundamentally broken.  (Basically what happens is that
   competing threads can corrupt shared global state, one good example
   being regular expression engine's state.)

   Timing problems
   The following tests may fail intermittently because of timing problems,
   for example if the system is heavily loaded.


   In case of failure please try running them manually, for example

       ./perl -Ilib ext/Time/HiRes/HiRes.t

   Tied/Magical Array/Hash Elements Do Not Autovivify
   For normal arrays "$foo = \$bar[1]" will assign "undef" to $bar[1]
   (assuming that it didn't exist before), but for tied/magical arrays and
   hashes such autovivification does not happen because there is currently
   no way to catch the reference creation.  The same problem affects
   slicing over non-existent indices/keys of a tied/magical array/hash.

   Unicode in package/class and subroutine names does not work
   One can have Unicode in identifier names, but not in package/class or
   subroutine names.  While some limited functionality towards this does
   exist as of Perl 5.8.0, that is more accidental than designed; use of
   Unicode for the said purposes is unsupported.

   One reason of this unfinishedness is its (currently) inherent
   unportability: since both package names and subroutine names may need
   to be mapped to file and directory names, the Unicode capability of the
   filesystem becomes important-- and there unfortunately aren't portable

Platform Specific Problems

   *   If using the AIX native make command, instead of just "make" issue
       "make all".  In some setups the former has been known to spuriously
       also try to run "make install".  Alternatively, you may want to use
       GNU make.

   *   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 libC_r.

   *   vac May Produce Buggy Code For Perl

       The AIX C compiler vac version may produce buggy code,
       resulting in a few random tests failing when run as part of "make
       test", but when the failing tests are run by hand, they succeed.
       We suggest upgrading to at least vac version, that has been
       known to compile Perl correctly.  "lslpp -L|grep vac.C" will tell
       you the vac version.  See README.aix.

   *   If building threaded Perl, you may get compilation warning from

         "pp_sys.c", line 4651.39: 1506-280 (W) Function argument assignment between types "unsigned char*" and "const void*" is not allowed.

       This is harmless; it is caused by the getnetbyaddr() and
       getnetbyaddr_r() having slightly different types for their first

   Alpha systems with old gccs fail several tests
   If you see op/pack, op/pat, op/regexp, or ext/Storable tests failing in
   a Linux/alpha or *BSD/Alpha, it's probably time to upgrade your gcc.
   gccs prior to 2.95.3 are definitely not good enough, and gcc 3.1 may be
   even better.  (RedHat Linux/alpha with gcc 3.1 reported no problems, as
   did Linux 2.4.18 with gcc 2.95.4.)  (In Tru64, it is preferable to use
   the bundled C compiler.)

   Perl 5.8.0 doesn't build in AmigaOS.  It broke at some point during the
   ithreads work and we could not find Amiga experts to unbreak the
   problems.  Perl 5.6.1 still works for AmigaOS (as does the 5.7.2
   development release).

   The following tests fail on 5.8.0 Perl in BeOS Personal 5.03:

    t/op/lfs............................FAILED at test 17
    t/op/magic..........................FAILED at test 24
    ext/Fcntl/t/syslfs..................FAILED at test 17
    ext/File/Glob/t/basic...............FAILED at test 3
    ext/POSIX/t/sigaction...............FAILED at test 13
    ext/POSIX/t/waitpid.................FAILED at test 1

   (Note: more information was available in README.beos until support for
   BeOS was removed in Perl v5.18.0)

   Cygwin "unable to remap"
   For example when building the Tk extension for Cygwin, you may get an
   error message saying "unable to remap".  This is known problem with
   Cygwin, and a workaround is detailed in here:

   Cygwin ndbm tests fail on FAT
   One can build but not install (or test the build of) the NDBM_File on
   FAT filesystems.  Installation (or build) on NTFS works fine.  If one
   attempts the test on a FAT install (or build) the following failures
   are expected:

    ../ext/NDBM_File/ndbm.t       13  3328    71   59  83.10%  1-2 4 16-71
    ../ext/ODBM_File/odbm.t      255 65280    ??   ??       %  ??
    ../lib/AnyDBM_File.t           2   512    12    2  16.67%  1 4
    ../lib/Memoize/t/errors.t      0   139    11    5  45.45%  7-11
    ../lib/Memoize/t/tie_ndbm.t   13  3328     4    4 100.00%  1-4
    run/fresh_perl.t                          97    1   1.03%  91

   NDBM_File fails and ODBM_File just coredumps.

   If you intend to run only on FAT (or if using AnyDBM_File on FAT), run
   Configure with the -Ui_ndbm and -Ui_dbm options to prevent NDBM_File
   and ODBM_File being built.

   DJGPP Failures
    t/op/stat............................FAILED at test 29
    lib/File/Find/t/find.................FAILED at test 1
    lib/File/Find/t/taint................FAILED at test 1
    lib/h2xs.............................FAILED at test 15
    lib/Pod/t/eol........................FAILED at test 1
    lib/Test/Harness/t/strap-analyze.....FAILED at test 8
    lib/Test/Harness/t/test-harness......FAILED at test 23
    lib/Test/Simple/t/exit...............FAILED at test 1

   The above failures are known as of 5.8.0 with native builds with long
   filenames, but there are a few more if running under dosemu because of
   limitations (and maybe bugs) of dosemu:

    t/comp/cpp...........................FAILED at test 3

   and a few lib/ExtUtils tests, and several hundred Encode/t/Aliases.t
   failures that work fine with long filenames.  So you really might
   prefer native builds and long filenames.

   FreeBSD built with ithreads coredumps reading large directories
   This is a known bug in FreeBSD 4.5's readdir_r(), it has been fixed in
   FreeBSD 4.6 (see perlfreebsd (README.freebsd)).

   FreeBSD Failing locale Test 117 For ISO 8859-15 Locales
   The ISO 8859-15 locales may fail the locale test 117 in FreeBSD.  This
   is caused by the characters \xFF (y with diaeresis) and \xBE (Y with
   diaeresis) not behaving correctly when being matched case-
   insensitively.  Apparently this problem has been fixed in the latest
   FreeBSD releases.  ( )

   IRIX fails ext/List/Util/t/shuffle.t or Digest::MD5
   IRIX with MIPSpro or compiler may fail the List::Util
   test ext/List/Util/t/shuffle.t by dumping core.  This seems to be a
   compiler error since if compiled with gcc no core dump ensues, and no
   failures have been seen on the said test on any other platform.

   Similarly, building the Digest::MD5 extension has been known to fail
   with "*** Termination code 139 (bu21)".

   The cure is to drop optimization level (Configure -Doptimize=-O2).

   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 glibc 2.2.5 fails t/op/int subtest #6 with -Duse64bitint
   This is a known bug in the glibc 2.2.5 with long long integers.  ( )

   Linux With Sfio Fails op/misc Test 48
   No known fix.

   Mac OS X
   Please remember to set your environment variable LC_ALL to "C" (setenv
   LC_ALL C) before running "make test" to avoid a lot of warnings about
   the broken locales of Mac OS X.

   The following tests are known to fail in Mac OS X 10.1.5 because of
   buggy (old) implementations of Berkeley DB included in Mac OS X:

    Failed Test                 Stat Wstat Total Fail  Failed  List of Failed
    ../ext/DB_File/t/db-btree.t    0    11    ??   ??       %  ??
    ../ext/DB_File/t/db-recno.t              149    3   2.01%  61 63 65

   If you are building on a UFS partition, you will also probably see
   t/op/stat.t subtest #9 fail.  This is caused by Darwin's UFS not
   supporting inode change time.

   Also the ext/POSIX/t/posix.t subtest #10 fails but it is skipped for
   now because the failure is Apple's fault, not Perl's (blocked signals
   are lost).

   If you Configure with ithreads, ext/threads/t/libc.t will fail. Again,
   this is not Perl's fault-- the libc of Mac OS X is not threadsafe (in
   this particular test, the localtime() call is found to be

   Mac OS X dyld undefined symbols
   If after installing Perl 5.8.0 you are getting warnings about missing
   symbols, for example

       dyld: perl Undefined symbols

   you probably have an old pre-Perl-5.8.0 installation (or parts of one)
   in /Library/Perl (the undefined symbols used to exist in pre-5.8.0
   Perls).  It seems that for some reason "make install" doesn't always
   completely overwrite the files in /Library/Perl.  You can move the old
   Perl shared library out of the way like this:

       cd /Library/Perl/darwin/CORE
       mv libperl.dylib libperlold.dylib

   and then reissue "make install".  Note that the above of course is
   extremely disruptive for anything using the /usr/local/bin/perl.  If
   that doesn't help, you may have to try removing all the .bundle files
   from beneath /Library/Perl, and again "make install"-ing.

   OS/2 Test Failures
   The following tests are known to fail on OS/2 (for clarity only the
   failures are shown, not the full error messages):

    ../lib/ExtUtils/t/Mkbootstrap.t    1   256    18    1   5.56%  8
    ../lib/ExtUtils/t/Packlist.t       1   256    34    1   2.94%  17
    ../lib/ExtUtils/t/basic.t          1   256    17    1   5.88%  14
    lib/os2_process.t                  2   512   227    2   0.88%  174 209
    lib/os2_process_kid.t                        227    2   0.88%  174 209
    lib/rx_cmprt.t                   255 65280    18    3  16.67%  16-18

   op/sprintf tests 91, 129, and 130
   The op/sprintf tests 91, 129, and 130 are known to fail on some
   platforms.  Examples include any platform using sfio, and
   Compaq/Tandem's NonStop-UX.

   Test 91 is known to fail on QNX6 (nto), because "sprintf '%e',0"
   incorrectly produces 0.000000e+0 instead of 0.000000e+00.

   For tests 129 and 130, the failing platforms do not comply with the
   ANSI C Standard: lines 19ff on page 134 of 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 "-0".)

   The socketpair tests are known to be unhappy in SCO 3.2v5.0.4:

    ext/Socket/socketpair.t...............FAILED tests 15-45

   Solaris 2.5
   In case you are still using Solaris 2.5 (aka SunOS 5.5), you may
   experience failures (the test core dumping) in lib/locale.t.  The
   suggested cure is to upgrade your Solaris.

   Solaris x86 Fails Tests With -Duse64bitint
   The following tests are known to fail in Solaris x86 with Perl
   configured to use 64 bit integers:

    ext/Data/Dumper/t/dumper.............FAILED at test 268
    ext/Devel/Peek/Peek..................FAILED at test 7

   The following tests are known to fail on SUPER-UX:

    op/64bitint...........................FAILED tests 29-30, 32-33, 35-36
    op/arith..............................FAILED tests 128-130
    op/pack...............................FAILED tests 25-5625
    op/taint..............................# msgsnd failed
    ../ext/IO/lib/IO/t/io_poll............FAILED tests 3-4
    ../ext/IPC/SysV/ipcsysv...............FAILED tests 2, 5-6
    ../ext/IPC/SysV/t/msg.................FAILED tests 2, 4-6
    ../ext/Socket/socketpair..............FAILED tests 12
    ../lib/IPC/SysV.......................FAILED tests 2, 5-6
    ../lib/warnings.......................FAILED tests 115-116, 118-119

   The op/pack failure ("Cannot compress negative numbers at op/pack.t
   line 126") is serious but as of yet unsolved.  It points at some
   problems with the signedness handling of the C compiler, as do the
   64bitint, arith, and pow failures.  Most of the rest point at problems
   with SysV IPC.

   Term::ReadKey not working on Win32
   Use Term::ReadKey 2.20 or later.

   *   During Configure, the test

           Guessing which symbols your C compiler and preprocessor define...

       will probably fail with error messages like

           CC-20 cc: ERROR File = try.c, Line = 3
             The identifier "bad" is undefined.

             bad switch yylook 79bad switch yylook 79bad switch yylook 79bad switch yylook 79#ifdef A29K

           CC-65 cc: ERROR File = try.c, Line = 3
             A semicolon is expected at this point.

       This is caused by a bug in the awk utility of UNICOS/mk.  You can
       ignore the error, but it does cause a slight problem: you cannot
       fully benefit from the h2ph utility (see h2ph) that can be used to
       convert C headers to Perl libraries, mainly used to be able to
       access from Perl the constants defined using C preprocessor, cpp.
       Because of the above error, parts of the converted headers will be
       invisible.  Luckily, these days the need for h2ph is rare.

   *   If building Perl with interpreter threads (ithreads), the
       getgrent(), getgrnam(), and getgrgid() functions cannot return the
       list of the group members due to a bug in the multithreaded support
       of UNICOS/mk.  What this means is that in list context the
       functions will return only three values, not four.

   There are a few known test failures.  (Note: the relevant information
   was available in README.uts until support for UTS was removed in Perl

   VOS (Stratus)
   When Perl is built using the native build process on VOS Release 14.5.0
   and GNU C++/GNU Tools 2.0.1, all attempted tests either pass or result
   in TODO (ignored) failures.

   There should be no reported test failures with a default configuration,
   though there are a number of tests marked TODO that point to areas
   needing further debugging and/or porting work.

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

   XML::Parser not working
   Use XML::Parser 2.31 or later.

   z/OS (OS/390)
   z/OS has rather many test failures but the situation is actually much
   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/Data/Dumper/t/dumper.t              357    8   2.24%  311 314 325 327
                                                                 331 333 337 339
    ../ext/IO/lib/IO/t/io_unix.t                 5    4  80.00%  2-5
    ../ext/Storable/t/downgrade.t   12  3072   169   12   7.10%  14-15 46-47 78-79
                                                                 110-111 150 161
    ../lib/ExtUtils/t/Constant.t   121 30976    48   48 100.00%  1-48
    ../lib/ExtUtils/t/Embed.t                    9    9 100.00%  1-9
    op/pat.t                                   922    7   0.76%  665 776 785 832-
                                                                 834 845
    op/sprintf.t                               224    3   1.34%  98 100 136
    op/tr.t                                     97    5   5.15%  63 71-74
    uni/fold.t                                 780    6   0.77%  61 169 196 661

   The failures in dumper.t and downgrade.t are problems in the tests,
   those in io_unix and sprintf are problems in the USS (UDP sockets and
   printf formats).  The pat, tr, and fold failures are genuine Perl
   problems caused by EBCDIC (and in the pat and fold cases, combining
   that with Unicode).  The Constant and Embed are probably problems in
   the tests (since they test Perl's ability to build extensions, and that
   seems to be working reasonably well.)

   Unicode Support on EBCDIC Still Spotty
   Though mostly working, Unicode support still has problem spots on
   EBCDIC platforms.  One such known spot are the "\p{}" and "\P{}"
   regular expression constructs for code points less than 256: the "pP"
   are testing for Unicode code points, not knowing about EBCDIC.

   Seen In Perl 5.7 But Gone Now
   "Time::Piece" (previously known as "Time::Object") was removed because
   it was felt that it didn't have enough value in it to be a core module.
   It is still a useful module, though, and is available from the CPAN.

   Perl 5.8 unfortunately does not build anymore on AmigaOS; this broke
   accidentally at some point.  Since there are not that many Amiga
   developers available, we could not get this fixed and tested in time
   for 5.8.0.  Perl 5.6.1 still works for AmigaOS (as does the 5.7.2
   development release).

   The "PerlIO::Scalar" and "PerlIO::Via" (capitalised) were renamed as
   "PerlIO::scalar" and "PerlIO::via" (all lowercase) just before 5.8.0.
   The main rationale was to have all core PerlIO layers to have all
   lowercase names.  The "plugins" are named as usual, for example

   The "threads::shared::queue" and "threads::shared::semaphore" were
   renamed as "Thread::Queue" and "Thread::Semaphore" just before 5.8.0.
   The main rationale was to have thread modules to obey normal naming,
   "Thread::" (the "threads" and "threads::shared" themselves are more
   pragma-like, they affect compile-time, so they stay lowercase).

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.


   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 <>.

More Linux Commands

mdadm.conf(5) - configuration for management of Software RAI
mdadm is a tool for creating, managing, and monitoring RAID devices using the md driver in Linux. Some common tasks, such as assembling all arrays, can be simpl

Tcl_AppInit(3) - perform application-specific initialization
Tcl_AppInit is a hook procedure that is invoked by the main programs for Tcl applications such as tclsh and wish. Its purpose is to allow new Tcl applications t

mitem_userptr(3menu) - associate application data with a men
Every menu item has a field that can be used to hold application-specific data (that is, the menu-driver code leaves it alone). These functions get and set that

gij-4.6(1) - GNU interpreter for Java bytecode (Man Page)...
gij is a Java bytecode interpreter included with libgcj. gij is not available on every platform; porting it requires a small amount of assembly programming whic

menu_hook(3menu) - set hooks for automatic invocation by app
These functions make it possible to set hook functions to be called at various points in the automatic processing of input event codes by menu_driver. The funct

clnt_spcreateerror(3) - library routines for remote procedur
These routines allow C programs to make procedure calls on other machines across the network. First, the client calls a procedure to send a data packet to the s

mbchk(1) - check the format of a Multiboot kernel (ManPage)
Check if the format of FILE complies with the Multiboot Specification. -q, --quiet suppress all normal output -h, --help display this help and exit -v, --versio

sqlite_table(5) - Postfix SQLite configuration (Man Page)...
sqlite_table.5 - The Postfix mail system uses optional tables for address rewriting or mail routing. These tables are usually in dbm or db format. Alternatively

XIGrabKeycode(3) - grab/ungrab buttons or keys (Man Page)...
XIGrabButton and XIGrabKeycode establishes a passive grab. The modifier device for a button grab is the paired master device if deviceid specifies a master poin

current_field(3form) - set and get form page number.........
current_field.3form - The function set_current field sets the current field of the given form; current_field returns the current field of the given form. The fu

xclock(1) - analog / digital clock for X - Linux man page...
The xclock program displays the time in analog or digital form. The time is continuously updated at a frequency which may be specified by the user. OPTIONS Xclo

audispd(8) an event multiplexor (Admin - Linux man page)....
audispd is an audit event multiplexor. It has to be started by the audit daemon in order to get events. It takes audit events and distributes them to child prog

We can't live, work or learn in freedom unless the software we use is free.