perl584delta - what is new for perl v5.8.4


   This document describes differences between the 5.8.3 release and the
   5.8.4 release.

Incompatible Changes

   Many minor bugs have been fixed. Scripts which happen to rely on
   previously erroneous behaviour will consider these fixes as
   incompatible changes :-) You are advised to perform sufficient
   acceptance testing on this release to satisfy yourself that this does
   not affect you, before putting this release into production.

   The diagnostic output of Carp has been changed slightly, to add a space
   after the comma between arguments. This makes it much easier for tools
   such as web browsers to wrap it, but might confuse any automatic tools
   which perform detailed parsing of Carp output.

   The internal dump output has been improved, so that non-printable
   characters such as newline and backspace are output in "\x" notation,
   rather than octal. This might just confuse non-robust tools which parse
   the output of modules such as Devel::Peek.

Core Enhancements

   Malloc wrapping
   Perl can now be built to detect attempts to assign pathologically large
   chunks of memory.  Previously such assignments would suffer from
   integer wrap-around during size calculations causing a misallocation,
   which would crash perl, and could theoretically be used for "stack
   smashing" attacks.  The wrapping defaults to enabled on platforms where
   we know it works (most AIX configurations, BSDi, Darwin, DEC OSF/1,
   FreeBSD, HP/UX, GNU Linux, OpenBSD, Solaris, VMS and most Win32
   compilers) and defaults to disabled on other platforms.

   Unicode Character Database 4.0.1
   The copy of the Unicode Character Database included in Perl 5.8 has
   been updated to 4.0.1 from 4.0.0.

   suidperl less insecure
   Paul Szabo has analysed and patched "suidperl" to remove existing known
   insecurities. Currently there are no known holes in "suidperl", but
   previous experience shows that we cannot be confident that these were
   the last. You may no longer invoke the set uid perl directly, so to
   preserve backwards compatibility with scripts that invoke
   #!/usr/bin/suidperl the only set uid binary is now "sperl5.8."n
   ("sperl5.8.4" for this release). "suidperl" is installed as a hard link
   to "perl"; both "suidperl" and "perl" will invoke "sperl5.8.4"
   automatically the set uid binary, so this change should be completely

   For new projects the core perl team would strongly recommend that you
   use dedicated, single purpose security tools such as "sudo" in
   preference to "suidperl".

   In addition to bug fixes, "format"'s features have been enhanced. See

Modules and Pragmata

   The (mis)use of "/tmp" in core modules and documentation has been
   tidied up.  Some modules available both within the perl core and
   independently from CPAN ("dual-life modules") have not yet had these
   changes applied; the changes will be integrated into future stable perl
   releases as the modules are updated on CPAN.

   Updated modules
       There is experimental support for Linux abstract Unix domain

       Synced with its CPAN version 2.10

       "syslog()" can now use numeric constants for facility names and
       priorities, in addition to strings.

   Win32 has moved from the libwin32 module to core Perl

       Detached threads are now also supported on Windows.


Performance Enhancements

   *   Accelerated Unicode case mappings ("/i", "lc", "uc", etc).

   *   In place sort optimised (eg "@a = sort @a")

   *   Unnecessary assignment optimised away in

         my $s = undef;
         my @a = ();
         my %h = ();

   *   Optimised "map" in scalar context

Utility Changes

   The Perl debugger (lib/ can now save all debugger commands
   for sourcing later, and can display the parent inheritance tree of a
   given class.

Installation and Configuration Improvements

   The build process on both VMS and Windows has had several minor
   improvements made. On Windows Borland's C compiler can now compile perl
   with PerlIO and/or USE_LARGE_FILES enabled.

   "perl.exe" on Windows now has a "Camel" logo icon. The use of a camel
   with the topic of Perl is a trademark of O'Reilly and Associates Inc.,
   and is used with their permission (ie distribution of the source,
   compiling a Windows executable from it, and using that executable
   locally). Use of the supplied camel for anything other than a perl
   executable's icon is specifically not covered, and anyone wishing to
   redistribute perl binaries with the icon should check directly with
   O'Reilly beforehand.

   Perl should build cleanly on Stratus VOS once more.

Selected Bug Fixes

   More utf8 bugs fixed, notably in how "chomp", "chop", "send", and
   "syswrite" and interact with utf8 data. Concatenation now works
   correctly when "use bytes;" is in scope.

   Pragmata are now correctly propagated into (?{...}) constructions in
   regexps.  Code such as

      my $x = qr{ ... (??{ $x }) ... };

   will now (correctly) fail under use strict. (As the inner $x is and has
   always referred to $::x)

   The "const in void context" warning has been suppressed for a constant
   in an optimised-away boolean expression such as "5 || print;"

   "perl -i" could "fchmod(stdin)" by mistake. This is serious if stdin is
   attached to a terminal, and perl is running as root. Now fixed.

New or Changed Diagnostics

   "Carp" and the internal diagnostic routines used by "Devel::Peek" have
   been made clearer, as described in "Incompatible Changes"

Changed Internals

   Some bugs have been fixed in the hash internals. Restricted hashes and
   their place holders are now allocated and deleted at slightly different
   times, but this should not be visible to user code.

Future Directions

   Code freeze for the next maintenance release (5.8.5) will be on 30th
   June 2004, with release by mid July.

Platform Specific Problems

   This release is known not to build on Windows 95.

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.  You can browse and search the Perl 5 bugs at


   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.


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