=head1 DESCRIPTION
-This document describes differences between the 5.6.0 release and the
-5.8.0 release.
+This document describes differences between the 5.6.0 release
+and the 5.8.0 release.
-=head1 Incompatible Changes
-
-=over 4
-
-=item *
-
-The semantics of bless(REF, REF) were unclear and until someone proves
-it to make some sense, it is forbidden.
-
-=item *
-
-A reference to a reference now stringify as "REF(0x81485ec)" instead
-of "SCALAR(0x81485ec)" in order to be more consistent with the return
-value of ref().
-
-=item *
-
-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.
-
-=item *
-
-The obsolete chat2 library that should never have been allowed
-to escape the laboratory has been decommissioned.
-
-=item *
+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.
-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.
+If you are upgrading from Perl 5.005_03, you might also want
+to read L<perl56delta>.
-=item *
+=head1 Highlights In 5.8.0
-The (bogus) escape sequences \8 and \9 now give an optional warning
-("Unrecognized escape passed through"). There is no need to \-escape
-any C<\w> character.
+=over 4
=item *
-lstat(FILEHANDLE) now gives a warning because the operation makes no sense.
-In future releases this may become a fatal error.
+Better Unicode support
=item *
-The long deprecated uppercase aliases for the string comparison
-operators (EQ, NE, LT, LE, GE, GT) have now been removed.
+New Thread Implementation
=item *
-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.
+Many New Modules
=item *
-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', ...).
+Better Numeric Accuracy
=item *
-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 L</"Performance Enhancements">.
+Safe Signals
=item *
-The list of filenames from glob() (or <...>) is now by default sorted
-alphabetically to be csh-compliant. (bsd_glob() does still sort platform
-natively, ASCII or EBCDIC, unless GLOB_ALPHASORT is specified.)
+More Extensive Regression Testing
=back
+=head1 Incompatible Changes
+
=head2 64-bit platforms and malloc
-If your pointers are 64 bits wide, the Perl malloc is no more being
-used because it simply does not work with 8-byte pointers. Also,
-usually the system malloc on such platforms are much better optimized
-for such large memory models than the Perl malloc.
+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 (like modperl) tend to prefer
+the system malloc. Such platforms include Alpha and 64-bit HPPA,
+MIPS, PPC, and Sparc.
=head2 AIX Dynaloading
modules. The change was made to make Perl more compliant with other
applications like modperl which are using the AIX native interface.
+=head2 Attributes for C<my> variables now handled at run-time.
+
+The C<my EXPR : ATTRS> syntax now applies variable attributes at
+run-time. (Subroutine and C<our> variables still get attributes applied
+at compile-time.) See L<attributes> for additional details. In particular,
+however, this allows variable attributes to be useful for C<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).
+
=head2 Socket Extension Dynamic in VMS
The Socket extension is now dynamically loaded instead of being
TCP/IP stacks of VMS: we do not know since we weren't able to test
Perl in such configurations.
+=head2 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.
+
=head2 Different Definition of the Unicode Character Classes \p{In...}
As suggested by the Unicode consortium, the Unicode character classes
what C<\p{InHebrew}> meant in perl 5.6.0. For the full list
of affected character classes, see L<perlunicode/Blocks>.
+=head2 Perl Parser Stress Tested
+
+The Perl parser has been stress tested using both random input and
+Markov chain input and the few found crashes and lockups have been
+fixed.
+
+=head2 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().
+
=head2 Deprecations
-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 C<fields> pragma interface will remain
-available.
+=over 4
-The syntaxes C<@a->[...]> and C<@h->{...}> have now been deprecated.
+=item *
-The suidperl is also considered to be too much a risk to continue
-maintaining and the suidperl code is likely to be removed in a future
-release.
+The semantics of bless(REF, REF) were unclear and until someone proves
+it to make some sense, it is forbidden.
-The C<package;> syntax (C<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, C<use strict;> instead.
+=item *
-The chdir(undef) and chdir('') behaviors to match chdir() has been
-deprecated. In future versions, chdir(undef) and chdir('') will
-simply fail.
+The obsolete chat2 library that should never have been allowed
+to escape the laboratory has been decommissioned.
-=head1 Core Enhancements
+=item *
-=over 4
+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.
=item *
-C<perl -d:Module=arg,arg,arg> now works (previously one couldn't pass
-in multiple arguments.)
+The (bogus) escape sequences \8 and \9 now give an optional warning
+("Unrecognized escape passed through"). There is no need to \-escape
+any C<\w> character.
=item *
-my __PACKAGE__ $obj now works.
+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.)
=item *
-C<no Module;> now works even if there is no "sub unimport" in the Module.
+Spurious syntax errors generated in certain situations, when glob()
+caused File::Glob to be loaded for the first time, have been fixed.
=item *
-The numerical comparison operators return C<undef> if either operand
-is a NaN. Previously the behaviour was unspecified.
+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 L</"Performance Enhancements">.
=item *
-C<pack('U0a*', ...)> can now be used to force a string to UTF8.
+lstat(FILEHANDLE) now gives a warning because the operation makes no sense.
+In future releases this may become a fatal error.
=item *
-prototype(\&) is now available.
+The C<package;> syntax (C<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, C<use strict;> instead.
=item *
-There is now an UNTIE method.
+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.
+
+=item *
-=back
+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 C<fields> pragma interface will remain
+available.
-=head2 AUTOLOAD Is Now Lvaluable
+=item *
-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 syntaxes C<< @a->[...] >> and C<< %h->{...} >> have now been deprecated.
+
+=item *
+
+After years of trying the 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.
+
+=item *
+
+The long deprecated uppercase aliases for the string comparison
+operators (EQ, NE, LT, LE, GE, GT) have now been removed.
+
+=item *
+
+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', ...).
+
+=back
+
+=head1 Core Enhancements
=head2 PerlIO is Now The Default
creates a pipe, and runs the equivalent of exec('cat', '/etc/motd') in
the child process.
-=item *
-
-The following builtin functions are now overridable: chop(), chomp(),
-each(), keys(), pop(), push(), shift(), splice(), unshift().
-
-=item *
-
-Formats now support zero-padded decimal fields.
+=back
-=item *
+=head2 Safe Signals
-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 into often slightly faster and always less lossy
-arithmetics. (Previously Perl always preferred floating point numbers
-in its math.)
+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).
-=item *
+This change may have surprising side effects because signals no more
+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.
-The printf() and sprintf() now support parameter reordering using the
-C<%\d+\$> and C<*\d+\$> syntaxes. For example
+=head2 Unicode Overhaul
- print "%2\$s %1\$s\n", "foo", "bar";
+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.
-will print "bar foo\n"; This feature helps in writing
-internationalised software.
+=over 4
=item *
-Unicode in general should be now much more usable. Unicode can be
-used in hash keys, Unicode in regular expressions should work now,
-Unicode in tr/// should work now (though tr/// seems to be a
-particularly tricky to get right, so you have been warned)
+The Unicode Character Database coming with Perl has been upgraded
+to Unicode 3.1.1. For more information, see http://www.unicode.org/.
=item *
-The Unicode Character Database coming with Perl has been upgraded
-to Unicode 3.1. For more information, see http://www.unicode.org/,
-and http://www.unicode.org/unicode/reports/tr27/
-
For developers interested in enhancing Perl's Unicode capabilities:
almost all the UCD files are included with the Perl distribution in
-the lib/unicode subdirectory. The most notable omission, for space
+the lib/unicore subdirectory. The most notable omission, for space
considerations, is the Unihan database.
=item *
=back
-=head2 Signals Are Now Safe
-
-Perl used to be fragile in that signals arriving at inopportune moments
-could corrupt Perl's internal state.
-
=head2 Understanding of Numbers
In general a lot of fixing has happened in the area of Perl's
and C<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.)
+
+=head2 Miscellaneous Enhancements
+
=over 4
=item *
-The rules for allowing underscores (underbars) in numeric constants
-have been relaxed and simplified: now you can have an underscore
-B<between digits>.
+AUTOLOAD is now lvaluable, meaning that you can add the :lvalue attribute
+to AUTOLOAD subroutines and you can assign to the AUTOLOAD return value.
=item *
-GMAGIC (right-hand side magic) could in many cases such as string
-concatenation be invoked too many times.
+C<perl -d:Module=arg,arg,arg> now works (previously one couldn't pass
+in multiple arguments.)
=item *
-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.
+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
+L<perlembed>.
=item *
-Lexicals II: lexicals leaked at file scope into subroutines that
-were declared before the lexicals.
+Formats now support zero-padded decimal fields.
=item *
Lvalue subroutines can now return C<undef> in list context.
+However, the lvalue subroutine feature still remains experimental.
=item *
-The C<op_clear> and C<op_null> are now exported.
+A new special regular expression variable has been introduced:
+C<$^N>, which contains the most-recently closed group (submatch).
=item *
-A new special regular expression variable has been introduced:
-C<$^N>, which contains the most-recently closed group (submatch).
+C<no Module;> now works even if there is no "sub unimport" in the Module.
=item *
-L<utime> now supports C<utime undef, undef, @files> to change the
-file timestamps to the current time.
+The numerical comparison operators return C<undef> if either operand
+is a NaN. Previously the behaviour was unspecified.
=item *
-The Perl parser has been stress tested using both random input and
-Markov chain input.
+The following builtin functions are now overridable: each(), keys(),
+pop(), push(), shift(), splice(), unshift().
=item *
-C<eval "v200"> now works.
+C<pack('U0a*', ...)> can now be used to force a string to UTF8.
=item *
-VMS now works under PerlIO.
+my __PACKAGE__ $obj now works.
=item *
-END blocks are now run even if you exit/die in a BEGIN block.
-The execution of END blocks is now controlled by
-PL_exit_flags & PERL_EXIT_DESTRUCT_END. This enables the new
-behaviour for perl embedders. This will default in 5.10. See
-L<perlembed>.
+The printf() and sprintf() now support parameter reordering using the
+C<%\d+\$> and C<*\d+\$> syntaxes. For example
-=back
+ print "%2\$s %1\$s\n", "foo", "bar";
-=head1 Modules and Pragmata
+will print "bar foo\n". This feature helps in writing
+internationalised software, and in general when the order
+of the parameters can vary.
+
+=item *
-=head2 New Modules
+prototype(\&) is now available.
-=over 4
+=item *
+
+prototype(\[$@%&]) is now available to implicitly create references
+(useful for example if you want to emulate the tie() interface).
=item *
-File::Temp allows one to create temporary files and directories in an
-easy, portable, and secure way.
+untie() will now call an UNTIE() hook if it exists. See L<perltie>
+for details.
=item *
-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.
+L<utime> now supports C<utime undef, undef, @files> to change the
+file timestamps to the current time.
=item *
-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.
+The rules for allowing underscores (underbars) in numeric constants
+have been relaxed and simplified: now you can have an underscore
+simply B<between digits>.
+
+=back
-See L<B::Concise> for more information.
+=head1 Modules and Pragmata
+
+=head2 New Modules and Pragmata
+
+=over 4
=item *
-Class::ISA, by Sean Burke, for reporting the search path for a
-class's ISA tree, has been added.
+C<Attribute::Handlers> allows a class to define attribute handlers.
-See L<Class::ISA> for more information.
+ 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).
=item *
-Cwd has now a split personality: if possible, an extension is used,
-(this will hopefully be both faster and more secure and robust) but
-if not possible, the familiar Perl library implementation is used.
+B<B::Concise> is a new compiler backend for walking the Perl syntax
+tree, printing concise info about ops, from Stephen McCamant. The
+output is highly customisable. See L<B::Concise>.
=item *
-Digest, a frontend module for calculating digests (checksums),
-from Gisle Aas, has been added.
+C<Class::ISA> for reporting the search path for a class's ISA tree,
+by Sean Burke, has been added. See L<Class::ISA>.
+
+=item *
-See L<Digest> for more information.
+C<Cwd> has now 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.
=item *
-Digest::MD5 for calculating MD5 digests (checksums), by Gisle Aas,
-has been added.
+C<Devel::PPPort>, originally from Kenneth Albanowski and now
+maintained by Paul Marquess, has been added. It is primarily used
+by C<h2xs> to enhance portability of of XS modules between different
+versions of Perl.
+
+=item *
+
+C<Digest>, frontend module for calculating digests (checksums), from
+Gisle Aas, has been added. See L<Digest>.
+
+=item *
+
+C<Digest::MD5> for calculating MD5 digests (checksums) as defined in
+RFC 1321, from Gisle Aas, has been added. See L<Digest::MD5>.
use Digest::MD5 'md5_hex';
print $digest, "\n"; # 01d19d9d2045e005c3f1b80e8b164de1
-NOTE: the MD5 backward compatibility module is deliberately not
-included since its use is discouraged.
-
-See L<Digest::MD5> for more information.
+NOTE: the C<MD5> backward compatibility module is deliberately not
+included since its further use is discouraged.
=item *
-Encode, by Nick Ing-Simmons, provides a mechanism to translate
+C<Encode>, by Nick Ing-Simmons, provides a mechanism to translate
between different character encodings. Support for Unicode,
ISO-8859-*, ASCII, CP*, KOI8-R, and three variants of EBCDIC are
compiled in to the module. Several other encodings (like Japanese,
Chinese, and MacIntosh encodings) are included and will be loaded at
-runtime.
+runtime. See L<Encode>.
Any encoding supported by Encode module is also available to the
":encoding()" layer if PerlIO is used.
-See L<Encode> for more information.
+=item *
+
+C<I18N::Langinfo> can be use to query locale information.
+See L<I18N::Langinfo>.
+
+=item *
+
+C<I18N::LangTags> has functions for dealing with RFC3066-style
+language tags, by Sean Burke. See L<I18N::LangTags>.
+
+=item *
+
+C<ExtUtils::Constant> is a new tool for extension writers for
+generating XS code to import C header constants, by Nicholas Clark.
+See L<ExtUtils::Constant>.
=item *
-Filter::Simple is an easy-to-use frontend to Filter::Util::Call,
-from Damian Conway.
+C<Filter::Simple> is an easy-to-use frontend to Filter::Util::Call,
+from Damian Conway. See L<Filter::Simple>.
# in MyFilter.pm:
print "red\n"; # this code is not filtered, will print "red\n"
-See L<Filter::Simple> for more information.
-
=item *
-Filter::Util::Call, by Paul Marquess, provides you with the
-framework to write I<Source Filters> in Perl. For most uses
-the frontend Filter::Simple is to be preferred.
-See L<Filter::Util::Call> for more information.
+C<File::Temp> allows one to create temporary files and directories in
+an easy, portable, and secure way, by Tim Jenness. See L<File::Temp>.
=item *
-Locale::Constants, Locale::Country, Locale::Currency, and Locale::Language,
-from Neil Bowers, have been added. They provide the codes for various
-locale standards, such as "fr" for France, "usd" for US Dollar, and
-"jp" for Japanese.
+C<Filter::Util::Call> provides you with the framework to write
+I<Source Filters> in Perl, from Paul Marquess. For most uses the
+frontend Filter::Simple is to be preferred. See L<Filter::Util::Call>.
- use Locale::Country;
+=item *
+
+L<libnet> is a collection of perl5 modules related to network
+programming, from Graham Barr. See L<Net::FTP>, L<Net::NNTP>,
+L<Net::Ping>, L<Net::POP3>, L<Net::SMTP>, and L<Net::Time>.
+
+Perl installation leaves libnet unconfigured, use F<libnetcfg> to configure.
+
+=item *
+
+C<List::Util> is a selection of general-utility list subroutines, like
+sum(), min(), first(), and shuffle(), by Graham Barr. See L<List::Util>.
+
+=item *
+
+C<Locale::Constants>, C<Locale::Country>, C<Locale::Currency>, and
+C<Locale::Language>, from Neil Bowers, have been added. They provide the
+codes for various locale standards, such as "fr" for France, "usd" for
+US Dollar, and "jp" for Japanese.
+
+ use Locale::Country;
$country = code2country('jp'); # $country gets 'Japan'
$code = country2code('Norway'); # $code gets 'no'
See L<Locale::Constants>, L<Locale::Country>, L<Locale::Currency>,
-and L<Locale::Language> for more information.
+and L<Locale::Language>.
+
+=item *
+
+C<Locale::Maketext> is localization framework from Sean Burke. See
+L<Locale::Maketext>, and L<Locale::Maketext::TPJ13>. The latter is an
+article about software localization, originally published in The Perl
+Journal #13, republished here with kind permission.
+
+=item *
+
+C<Memoize> can make your functions faster by trading space for time,
+from Mark-Jason Dominus. See L<Memoize>.
=item *
-MIME::Base64, by Gisle Aas, allows you to encode data in base64.
+C<MIME::Base64> allows you to encode data in base64, from Gisle Aas,
+as defined in RFC 2045 - I<MIME (Multipurpose Internet Mail
+Extensions)>.
use MIME::Base64;
print $encoded, "\n"; # "QWxhZGRpbjpvcGVuIHNlc2FtZQ=="
-See L<MIME::Base64> for more information.
+See L<MIME::Base64>.
=item *
-MIME::QuotedPrint, by Gisle Aas, allows you to encode data in
-quoted-printable encoding.
+C<MIME::QuotedPrint> allows you to encode data in quoted-printable
+encoding, as defined in RFC 2045 - I<MIME (Multipurpose Internet Mail
+Extensions)>, from Gisle Aas.
use MIME::QuotedPrint;
necessary to use it with PerlIO::Via as in :
use MIME::QuotedPrint;
- open($fh,">Via(MIME::QuotedPrint)",$path)
+ open($fh,">Via(MIME::QuotedPrint)",$path);
+
+See L<MIME::QuotedPrint>.
+
+=item *
-See L<MIME::QuotedPrint> for more information.
+C<NEXT> is pseudo-class for method redispatch, from Damian Conway.
+See L<NEXT>.
=item *
-PerlIO::Scalar, by Nick Ing-Simmons, provides the implementation of
-IO to "in memory" Perl scalars as discussed above. It also serves as
-an example of a loadable layer. Other future possibilities include
-PerlIO::Array and PerlIO::Code. See L<PerlIO::Scalar> for more
-information.
+C<open> is a new pragma for setting the default I/O disciplines
+for open().
=item *
-PerlIO::Via, by Nick Ing-Simmons, acts as a PerlIO layer and wraps
-PerlIO layer functionality provided by a class (typically implemented
-in perl code).
+C<PerlIO::Scalar> provides the implementation of IO to "in memory"
+Perl scalars as discussed above, from Nick Ing-Simmons. It also
+serves as an example of a loadable PerlIO layer. Other future
+possibilities include PerlIO::Array and PerlIO::Code.
+See L<PerlIO::Scalar>.
+
+=item *
+
+C<PerlIO::Via> acts as a PerlIO layer and wraps PerlIO layer
+functionality provided by a class (typically implemented in perl
+code), from Nick Ing-Simmons.
use MIME::QuotedPrint;
- open($fh,">Via(MIME::QuotedPrint)",$path)
+ open($fh,">Via(MIME::QuotedPrint)",$path);
This will automatically convert everything output to C<$fh>
-to Quoted-Printable. See L<PerlIO::Via> for more information.
+to Quoted-Printable. See L<PerlIO::Via>.
+
+=item *
+
+C<Pod::ParseLink>, by Russ Allbery, has been added,
+to parse LZ<><> links in pods as described in the new
+perlpodspec.
=item *
-Pod::Text::Overstrike, by Joe Smith, has been added.
+C<Pod::Text::Overstrike>, by Joe Smith, has been added.
It converts POD data to formatted overstrike text.
-See L<Pod::Text::Overstrike> for more information.
+See L<Pod::Text::Overstrike>.
+
+=item *
+
+C<Scalar::Util> is a selection of general-utility scalar subroutines,
+like blessed(), reftype(), and tainted(). See L<Scalar::Util>.
+
+=item *
+
+C<sort> is a new pragma for controlling the behaviour of sort().
=item *
-Switch from Damian Conway has been added. Just by saying
+C<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, from Raphael Manfredi. See L<Storable>.
+
+=item *
+
+C<Switch>, from Damian Conway, has been added. Just by saying
use Switch;
else { print "previous case not true" }
}
-See L<Switch> for more information.
+See L<Switch>.
+
+=item *
+
+C<Test::More> is yet another framework for writing test scripts,
+more extensive than Test::Simple, by Michael Schwern. See L<Test::More>.
+
+=item *
+
+C<Test::Simple> has basic utilities for writing tests, by Michael
+Schwern. See L<Test::Simple>.
=item *
-Text::Balanced from Damian Conway has been added, for
-extracting delimited text sequences from strings.
+C<Text::Balanced> has been added, for extracting delimited text
+sequences from strings, from Damian Conway.
use Text::Balanced 'extract_delimited';
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 L<Text::Balanced> for more information.
-
-=item *
-
-Tie::RefHash::Nestable, by Edward Avis, allows storing hash references
-(unlike the standard Tie::RefHash) The module is contained within
-Tie::RefHash.
-
-=item *
-
-XS::Typemap, by Tim Jenness, is a test extension that exercises XS
-typemaps. Nothing gets installed but for extension writers the code
-is worth studying.
-
-=item *
-
-L<Attribute::Handlers> - Simpler definition of attribute handlers
+parsing algorithms. See L<Text::Balanced>.
=item *
-L<ExtUtils::Constant> - generate XS code to import C header constants
+C<threads> is an interface to interpreter threads, by Arthur Bergman.
+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 C<fork()> emulation). See L<threads>.
=item *
-L<I18N::Langinfo> - query locale information
+C<threads::shared> allows data sharing for interpreter threads, from
+Arthur Bergman. In the ithreads model any data sharing between
+threads must be explicit, as opposed to the old 5.005 thread model
+where data sharing was implicit. See L<threads::shared>.
=item *
-L<I18N::LangTags> - functions for dealing with RFC3066-style language tags
+C<Tie::RefHash::Nestable>, by Edward Avis, allows storing hash
+references (unlike the standard Tie::RefHash) The module is contained
+within Tie::RefHash, see L<Tie::RefHash>.
=item *
-L<libnet> - a collection of perl5 modules related to network programming
-
-Perl installation leaves libnet unconfigured, use F<libnetcfg> to configure.
+C<Time::HiRes> provides high resolution timing (ualarm, usleep,
+and gettimeofday), from Douglas E. Wegscheid. See L<Time::HiRes>.
=item *
-L<List::Util> - selection of general-utility list subroutines
+C<Unicode::UCD> offers a querying interface to the Unicode Character
+Database. See L<Unicode::UCD>.
=item *
-L<Locale::Maketext> - framework for localization
+C<Unicode::Collate> implements the UCA (Unicode Collation Algorithm)
+for sorting Unicode strings, by SADAHIRO Tomoyuki. See L<Unicode::Collate>.
=item *
-L<Memoize> - Make your functions faster by trading space for time
+C<Unicode::Normalize> implements the various Unicode normalization
+forms, by SADAHIRO Tomoyuki. See L<Unicode::Normalize>.
=item *
-L<NEXT> - pseudo-class for method redispatch
-
-=item *
+C<XS::Typemap>, by Tim Jenness, is a test extension that exercises XS
+typemaps. Nothing gets installed but for extension writers the code
+is worth studying.
-L<Scalar::Util> - selection of general-utility scalar subroutines
+=back
-=item *
+=head2 Updated And Improved Modules and Pragmata
-L<Test::More> - yet another framework for writing test scripts
+=over 4
=item *
-L<Test::Simple> - Basic utilities for writing tests
+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, Pod::Parser, Storable,
+Term::ANSIColor, Test, Text-Tabs+Wrap.
=item *
-L<Time::HiRes> - high resolution ualarm, usleep, and gettimeofday
+The attributes::reftype() now works on tied arguments.
=item *
-L<Time::Piece> - Object Oriented time objects
-
-(Previously known as L<Time::Object>.)
+AutoLoader can now be disabled with C<no AutoLoader;>.
=item *
-L<Time::Seconds> - a simple API to convert seconds to other date values
+B::Deparse has been significantly enhanced. It now can deparse almost
+all of the standard test suite (so that the tests still succeed).
+There is a make target "test.deparse" for trying this out.
=item *
-L<UnicodeCD> - Unicode Character Database
-
-=back
-
-=head2 Updated And Improved Modules and Pragmata
-
-=over 4
+Class::Struct can now define the classes in compile time.
=item *
-The following independently supported modules have been updated to
-newer versions from CPAN: CGI, CPAN, DB_File, File::Spec, Getopt::Long,
-the podlators bundle, Pod::LaTeX, Pod::Parser, Term::ANSIColor, Test.
+Class::Struct now assigns the array/hash element if the accessor
+is called with an array/hash element as the B<sole> argument.
=item *
-Bug fixes and minor enhancements have been applied to B::Deparse,
-Data::Dumper, IO::Poll, IO::Socket::INET, Math::BigFloat,
-Math::Complex, Math::Trig, Net::protoent, the re pragma, SelfLoader,
-Sys::SysLog, Test::Harness, Text::Wrap, UNIVERSAL, and the warnings
-pragma.
+Data::Dumper has now an option to sort hashes.
=item *
-The attributes::reftype() now works on tied arguments.
+Data::Dumper has now an option to dump code references
+using B::Deparse.
=item *
-AutoLoader can now be disabled with C<no AutoLoader;>,
+DB_File now supports newer Berkeley DB versions, among
+other improvements.
=item *
=item *
-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 work.
-
-=item *
-
-File::Glob::glob() renamed to File::Glob::bsd_glob() to avoid
-prototype mismatch with CORE::glob().
-
-=item *
-
-IPC::Open3 now allows the use of numeric file descriptors.
-
-=item *
-
-use lib now works identically to @INC. Removing directories
-with 'no lib' now works.
+Fcntl, Socket, and Sys::Syslog have been rewritten to use the
+new-style constant dispatch section (see L<ExtUtils::Constant>).
+This means that they will be more robust and hopefully faster.
=item *
-C<%INC> now localised in a Safe compartment so that use/require work.
+File::Find now chdir()s correctly when chasing symbolic links.
=item *
-The Shell module now has an OO interface.
+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 work.
=item *
-B::Deparse should be now more robust. It still far from providing a full
-round trip for any random piece of Perl code, though, and is under active
-development: expect more robustness in 5.7.2.
+File::Find is now (again) reentrant. It also has been made
+more portable.
=item *
-Class::Struct can now define the classes in compile time.
+File::Glob::glob() renamed to File::Glob::bsd_glob() to avoid
+prototype mismatch with CORE::glob().
=item *
-Math::BigFloat has undergone much fixing, and in addition the fmod()
-function now supports modulus operations.
-
-(The fixed Math::BigFloat module is also available in CPAN for those
-who can't upgrade their Perl: http://www.cpan.org/authors/id/J/JP/JPEACOCK/)
+File::Glob now supports C<GLOB_LIMIT> constant to limit the size of
+the returned list of filenames.
=item *
=item *
+IPC::Open3 now allows the use of numeric file descriptors.
+
+=item *
+
IO::Socket has now 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.
=item *
-Net::Ping has been enhanced. There is now "external" protocol which
-uses Net::Ping::External module which runs external ping(1) and parses
-the output. An alpha version of Net::Ping::External is available in
-CPAN and in 5.7.2 the Net::Ping::External may be integrated to Perl.
-
-=item *
-
-The C<open> pragma allows layers other than ":raw" and ":crlf" when
-using PerlIO.
+IO::Socket::INET now supports C<LocalPort> of zero (usually meaning
+that the operating system will make one up.)
=item *
-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.
+use lib now works identically to @INC. Removing directories
+with 'no lib' now works.
=item *
-The Test module has been significantly enhanced. Its use is
-greatly recommended for module writers.
+Math::BigFloat and Math::BigInt have undergone a full rewrite.
+They are now magnitudes faster, and they support various
+bignum libraries such as GMP and PARI as their backends.
=item *
-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 implemented.
-
-=back
-
-The following modules have been upgraded from the versions at CPAN:
-CPAN, CGI, DB_File, File::Temp, Getopt::Long, Pod::Man, Pod::Text,
-Storable, Text-Tabs+Wrap.
+Math::Complex handles inf, NaN etc., better.
=item *
-L<B::Deparse> module has been significantly enhanced. It now
-can deparse almost all of the standard test suite (so that the
-tests still succeed). There is a make target "test.deparse"
-for trying this out.
+Net::Ping has been enhanced. There is now "external" protocol which
+uses Net::Ping::External module which runs external ping(1) and parses
+the output. A version of Net::Ping::External is available in CPAN.
=item *
-L<Class::Struct> now assigns the array/hash element if the accessor
-is called with an array/hash element as the B<sole> argument.
+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.
=item *
-L<Cwd> extension is now (even) faster.
+In Safe the C<%INC> now localised in a Safe compartment so that
+use/require work.
=item *
-L<DB_File> extension has been updated to version 1.77.
+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.
=item *
-L<Fcntl>, L<Socket>, and L<Sys::Syslog> have been rewritten to use the
-new-style constant dispatch section (see L<ExtUtils::Constant>).
+In Search::Dict one can now have a pre-processing hook for the
+lines being searched.
=item *
-L<File::Find> is now (again) reentrant. It also has been made
-more portable.
+The Shell module now has an OO interface.
=item *
-L<File::Glob> now supports C<GLOB_LIMIT> constant to limit the
-size of the returned list of filenames.
+The Test module has been significantly enhanced.
=item *
-L<IO::Socket::INET> now supports C<LocalPort> of zero (usually meaning
-that the operating system will make one up.)
+The vars pragma now supports declaring fully qualified variables.
+(Something that C<our()> does not and will not support.)
=item *
-The L<vars> pragma now supports declaring fully qualified variables.
-(Something that C<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 implemented.
=back
=item *
-The Emacs perl mode (emacs/cperl-mode.el) has been updated to version
+Emacs perl mode (emacs/cperl-mode.el) has been updated to version
4.31.
=item *
-Perlbug is now much more robust. It also sends the bug report to
-perl.org, not perl.com.
+F<emacs/e2ctags.pl> is now much faster.
=item *
-The perlcc utility has been rewritten and its user interface (that is,
-command line) is much more like that of the UNIX C compiler, cc.
+C<h2ph> now supports C trigraphs.
=item *
-The xsubpp utility for extension writers now understands POD
-documentation embedded in the *.xs files.
+C<h2xs> now produces a template README.
=item *
-h2xs now produces template README.
+C<h2xs> now uses C<Devel::PPort> for better portability between
+different versions of Perl.
=item *
-s2p has been completely rewritten in Perl. (It is in fact a full
-implementation of sed in Perl.)
+C<h2xs> uses the new L<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 B<never> gets 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).
+L<h2xs> now also supports C trigraphs.
=item *
-xsubpp now supports OUT keyword.
+C<libnetcfg> has been added to configure the libnet.
=item *
-The F<emacs/e2ctags.pl> is now much faster.
+C<perlbug> is now much more robust. It also sends the bug report to
+perl.org, not perl.com.
=item *
-L<h2ph> now supports C trigraphs.
+C<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 C<perlcc -B> instead.)
=item *
-L<h2xs> uses the new L<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 B<never> gets 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).
-L<h2xs> now also supports C trigraphs.
+C<perlivp> is a new Installation Verification Procedure utility
+for running any time after installing Perl.
=item *
-L<libnetcfg> has been added to configure the libnet.
+C<pod2html> now allows specifying a cache directory.
=item *
-The F<Pod::Html> (and thusly L<pod2html>) now allows specifying
-a cache directory.
+C<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 C<psed> utility.)
+
+=item *
+
+C<xsubpp> now understands POD documentation embedded in the *.xs files.
+
+=item *
+
+C<xsubpp> now supports OUT keyword.
=back
=item *
+perlclib documents the internal replacements for standard C library
+functions. (Interesting only for extension writers and Perl core
+hackers.)
+
+=item *
+
perldebtut is a Perl debugging tutorial.
=item *
perlebcdic contains considerations for running Perl on EBCDIC platforms.
-Note that unfortunately EBCDIC platforms that used to supported back in
-Perl 5.005 are still unsupported by Perl 5.7.0; the plan, however, is to
-bring them back to the fold.
=item *
-perlnewmod tells about writing and submitting a new module.
+perlintro is a gentle introduction to Perl.
=item *
-perlposix-bc explains using Perl on the POSIX-BC platform
-(an EBCDIC mainframe platform).
+perliol documents the internals of PerlIO with layers.
=item *
-perlretut is a regular expression tutorial.
+perlmodstyle is a style guide for writing modules.
=item *
-perlrequick is a regular expressions quick-start guide.
-Yes, much quicker than perlretut.
+perlnewmod tells about writing and submitting a new module.
=item *
-perlutil explains the command line utilities packaged with the Perl
-distribution.
-
-=back
+perlpacktut is a pack() tutorial.
-=head2 perlclib
+=item *
-Internal replacements for standard C library functions.
-(Interesting only for extension writers and Perl core hackers.)
+perlpod has been rewritten to be clearer and to record the best
+practices gathered over the years.
-=head2 perliol
+=item *
-Internals of PerlIO with layers.
+perlpodspec is a more formal specification of the pod format,
+mainly of interest for writers of pod applications, not to
+people writing in pod.
-=head2 README.aix
+=item *
-Documentation on compiling Perl on AIX has been added. AIX has
-several different C compilers and getting the right patch level
-is essential. On install README.aix will be installed as L<perlaix>.
+perlretut is a regular expression tutorial.
-=head2 README.bs2000
+=item *
-Documentation on compiling Perl on the POSIX-BC platform (an EBCDIC
-mainframe environment) has been added.
+perlrequick is a regular expressions quick-start guide.
+Yes, much quicker than perlretut.
-This was formerly known as README.posix-bc but the name was considered
-to be too confusing (it has nothing to do with the POSIX module or the
-POSIX standard). On install README.bs2000 will be installed as L<perlbs2000>.
+=item *
-=head2 README.macos
+perltodo has been updated.
-In perl 5.7.1 (and in the 5.6.1) the MacPerl sources have been
-synchronised with the standard Perl sources. To compile MacPerl
-some additional steps are required, and this file documents those
-steps. On install README.macos will be installed as L<perlmacos>.
+=item *
-=head2 README.mpeix
+perltootc has been renamed as perltooc (to not to conflict
+with perltoot in filesystems restricted to "8.3" names)
-The README.mpeix has been podified, which means that this information
-about compiling and using Perl on the MPE/iX miniframe platform will
-be installed as L<perlmpeix>.
+=item *
-=head2 README.solaris
+perluniintro is an introduction to using Unicode in Perl
+(perlunicode is more of a reference)
-README.solaris has been created and Solaris wisdom from elsewhere
-in the Perl documentation has been collected there. On install
-README.solaris will be installed as L<perlsolaris>.
+=item *
-=head2 README.vos
+perlutil explains the command line utilities packaged with the Perl
+distribution.
-The README.vos has been podified, which means that this information
-about compiling and using Perl on the Stratus VOS miniframe platform
-will be installed as L<perlvos>.
+=back
-=head2 Porting/repository.pod
+The following platform-specific documents are available before
+the installation as README.I<platform>, and after the installation
+as perlI<platform>:
-Documentation on how to use the Perl source repository has been added.
+ perlaix perlamiga perlapollo perlbeos perlbs2000
+ perlce perlcygwin perldgux perldos perlepoc perlhpux
+ perlhurd perlmachten perlmacos perlmint perlmpeix
+ perlnetware perlos2 perlos390 perlplan9 perlqnx perlsolaris
+ perltru64 perluts perlvmesa perlvms perlvos perlwin32
=over 4
=item *
-L<Locale::Maketext::TPJ13> is an article about software localization,
-originally published in The Perl Journal #13, republished here with
-kind permission.
+The documentation for the POSIX-BC platform is called "BS2000", to avoid
+confusion with the Perl POSIX module.
=item *
-More README.$PLATFORM files have been converted into pod, which also
-means that they also be installed as perl$PLATFORM documentation
-files. The new files are L<perlapollo>, L<perlbeos>, L<perldgux>,
-L<perlhurd>, L<perlmint>, L<perlnetware>, L<perlplan9>, L<perlqnx>,
-and L<perltru64>.
-
-=item *
-
-The F<Todo> and F<Todo-5.6> files have been merged into L<perltodo>.
-
-=item *
-
-Use of the F<gprof> tool to profile Perl has been documented in
-L<perlhack>. There is a make target "perl.gprof" for generating a
-gprofiled Perl executable.
+The documentation for the WinCE platform is called "CE", to avoid
+confusion with the perlwin32 documentation on 8.3-restricted filesystems.
=back
=item *
-map() that changes the size of the list should now work faster.
-
-=item *
-
-sort() has been changed to use 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).
+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.
+
+=item *
+
+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 C<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 C<1> comes first is hard to know, since one C<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, C<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 $N doesn't just double the quicksort time,
+it I<quadruples> it. Quicksort has a worst case run time that can
+grow like N**2, so-called I<quadratic> behaviour, and it can happen
+on patterns that may well arise in normal use. You won't notice this
+for small arrays, but you I<will> notice it with larger arrays,
+and you may not live long enough for the sort to complete on arrays
+of a million elements. So the 5.8 quicksort scrambles large arrays
+before sorting them, as a statistical defence against quadratic behaviour.
+But that means if you sort the same large array twice, ties may be
+broken in different ways.
+
+Because of the unpredictability of tie-breaking order, and the quadratic
+worst-case behaviour, quicksort was I<almost> replaced completely with
+a stable mergesort. I<Stable> means that ties are broken to preserve
+the original order of appearance in the input array. So
+
+ sort { ($a % 2) <=> ($b % 2) } (3,1,4,1,5,9);
+
+will yield (4,3,1,1,5,9), guaranteed. The even and odd numbers
+appear in the output in the same order they appeared in the input.
+Mergesort has worst case O(NlogN) behaviour, the best value
+attainable. And, ironically, this mergesort does particularly
+well where quicksort goes quadratic: mergesort sorts (1..$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 I<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 B<stable> subpragma forces stable behaviour,
+regardless of algorithm. The B<_quicksort> and B<_mergesort>
+subpragmas are heavy-handed ways to select the underlying implementation.
+The leading C<_> 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.
=item *
=item *
+Configure support for pdp11-style memory models has been removed due
+to obsolescence.
+
+=item *
+
configure.gnu now works with options with whitespace in them.
=item *
=item *
+In AFS installations one can configure the root of the AFS to be
+somewhere else than the default F</afs> by using the Configure
+parameter C<-Dafsroot=/some/where/else>.
+
+=item *
+
APPLLIB_EXP, a less-know 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.
=item *
-Building Berkeley DB3 for compatibility modes for DB, NDBM, and ODBM
-has been documented in INSTALL.
+The version of Berkeley DB used when the Perl (and, presumably, the
+DB_File extension) was built is now available as
+C<@Config{qw(db_version_major db_version_minor db_version_patch)}>
+from Perl and as C<DB_VERSION_MAJOR_CFG DB_VERSION_MINOR_CFG
+DB_VERSION_PATCH_CFG> from C.
=item *
-If you are on IRIX or Tru64 platforms, new profiling/debugging options
-have been added, see L<perlhack> for more information about pixie and
-Third Degree.
+Building Berkeley DB3 for compatibility modes for DB, NDBM, and ODBM
+has been documented in INSTALL.
=item *
-In AFS installations one can configure the root of the AFS to be
-somewhere else than the default F</afs> by using the Configure
-parameter C<-Dafsroot=/some/where/else>.
+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.
=item *
-The version of Berkeley DB used when the Perl (and, presumably, the
-DB_File extension) was built is now available as
-C<@Config{qw(db_version_major db_version_minor db_version_patch)}>
-from Perl and as C<DB_VERSION_MAJOR_CFG DB_VERSION_MINOR_CFG
-DB_VERSION_PATCH_CFG> from C.
+In addition to config.over a new override file, config.arch, is
+available. That is supposed to be used by hints file writers for
+architecture-wide changes (as opposed to config.over which is for
+site-wide changes).
=item *
-The Thread extension is now not built at all under ithreads
-(C<Configure -Duseithreads>) because it wouldn't work anyway (the
-Thread extension requires being Configured with C<-Duse5005threads>).
+If your file system supports symbolic links you can build Perl outside
+of the source directory by
-=item *
+ mkdir /tmp/perl/build/directory
+ cd /tmp/perl/build/directory
+ sh /path/to/perl/source/Configure -Dmksymlinks ...
-The C<B::Deparse> compiler backend has been so significantly improved
-that almost the whole Perl test suite passes after being deparsed. A
-make target has been added to help in further testing: C<make test.deparse>.
+This will create in /tmp/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
-=back
+ make all test
-=head2 New Or Improved Platforms
+and Perl will be built and tested, all in /tmp/perl/build/directory.
-For the list of platforms known to support Perl,
-see L<perlport/"Supported Platforms">.
+=item *
-=over 4
+For Perl developers several new make targets for profiling
+and debugging have been added, see L<perlhack>.
+
+=over 8
=item *
-AIX dynamic loading should be now better supported.
+Use of the F<gprof> tool to profile Perl has been documented in
+L<perlhack>. There is a make target called "perl.gprof" for
+generating a gprofiled Perl executable.
=item *
-After a long pause, AmigaOS has been verified to be happy with Perl.
+If you have GCC 3, there is a make target called "perl.gcov" for
+creating a gcoved Perl executable for coverage analysis. See
+L<perlhack>.
+
+=item *
+
+If you are on IRIX or Tru64 platforms, new profiling/debugging options
+have been added, see L<perlhack> for more information about pixie and
+Third Degree.
+
+=back
+
+=item *
+
+Guidelines of how to construct minimal Perl installations have
+been added to INSTALL.
+
+=item *
+
+The Thread extension is now not built at all under ithreads
+(C<Configure -Duseithreads>) because it wouldn't work anyway (the
+Thread extension requires being Configured with C<-Duse5005threads>).
+
+But note that the Thread.pm interface is now shared by both
+thread models.
+
+=back
+
+=head2 New Or Improved Platforms
+
+For the list of platforms known to support Perl,
+see L<perlport/"Supported Platforms">.
+
+=over 4
+
+=item *
+
+AIX dynamic loading should be now better supported.
+
+=item *
+
+AIX should now work better with gcc, threads, and 64-bitness. Also the
+long doubles support in AIX should be better now. See L<perlaix>.
+
+=item *
+
+After a long pause, AmigaOS has been verified to be happy with Perl.
+
+=item *
+
+AtheOS (http://www.atheos.cx/) is a new platform.
+
+=item *
+
+DG/UX platform now supports the 5.005-style threads. See L<perldgux>.
+
+=item *
+
+DYNIX/ptx platform (a.k.a. dynixptx) is supported at or near osvers 4.5.2.
=item *
=item *
+MacOS X (or Darwin) should now be able to build Perl even on HFS+
+filesystems. (The case-insensitivity confused the Perl build process.)
+
+=item *
+
NCR MP-RAS is now supported.
=item *
+NetWare from Novell is now supported. See L<perlnetware>.
+
+=item *
+
NonStop-UX is now supported.
=item *
-Amdahl UTS is now supported.
+NEC SUPER-UX is now supported.
+
+=item *
+
+Amdahl UTS UNIX mainframe platform is now supported.
+
+=item *
+
+WinCE is now supported. See L<perlce>.
=item *
support for dynamic loading. This is not selected by default,
however, you must specify -Dusedl in the arguments of Configure.
+=back
+
+=head1 Selected Bug Fixes
+
+Numerous memory leaks and uninitialized memory accesses have been
+hunted down. Most importantly anonymous subs used to leak quite
+a bit.
+
+=over 4
+
=item *
-AIX should now work better with gcc, threads, and 64-bitness. Also the
-long doubles support in AIX should be better now. See L<perlaix>.
+The autouse pragma didn't work for Multi::Part::Function::Names.
=item *
-AtheOS (http://www.atheos.cx/) is a new platform.
+caller() could cause core dumps in certain situations. Carp was sometimes
+affected by this problem.
=item *
-DG/UX platform now supports the 5.005-style threads. See L<perldgux>.
+chop(@list) in list context returned the characters chopped in
+reverse order. This has been reversed to be in the right order.
=item *
-DYNIX/ptx platform (a.k.a. dynixptx) is supported at or near osvers 4.5.2.
+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.
=item *
-Several MacOS (Classic) portability patches have been applied. We
-hope to get a fully working port by 5.8.0. (The remaining problems
-relate to the changed IO model of Perl.) See L<perlmacos>.
+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 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.
=item *
-MacOS X (or Darwin) should now be able to build Perl even on HFS+
-filesystems. (The case-insensitivity confused the Perl build process.)
+The order of DESTROYs has been made more predictable.
=item *
-NetWare from Novell is now supported. See L<perlnetware>.
+Several debugger fixes: exit code now reflects the script exit code,
+condition C<"0"> now treated correctly, the C<d> command now checks
+line number, the C<$.> no longer gets corrupted, all debugger output
+now goes correctly to the socket if RemotePort is set.
=item *
-The Amdahl UTS UNIX mainframe platform is now supported.
+Perl 5.6.0 could emit spurious warnings about redefinition of dl_error()
+when statically building extensions into perl. This has been corrected.
-=back
+=item *
-=head1 Selected Bug Fixes
+L<dprofpp> -R didn't work.
-=over 4
+=item *
+C<*foo{FORMAT}> now works.
=item *
-Several debugger fixes: exit code now reflects the script exit code,
-condition C<"0"> now treated correctly, the C<d> command now checks
-line number, the C<$.> no longer gets corrupted, all debugger output now
-goes correctly to the socket if RemotePort is set.
+Infinity is now recognized as a number.
=item *
-C<*foo{FORMAT}> now works.
+UNIVERSAL::isa no longer caches methods incorrectly. (This broke
+the Tk extension with 5.6.0.)
+
+=item *
+
+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.
+
+=item *
+
+Lexicals II: lexicals leaked at file scope into subroutines that
+were declared before the lexicals.
+
+=item *
+
+Lexical warnings now propagating correctly between scopes
+and into C<eval "...">.
=item *
-Lexical warnings now propagating correctly between scopes.
+C<use warnings qw(FATAL all)> did not work as intended. This has been
+corrected.
+
+=item *
+
+warnings::enabled() now reports the state of $^W correctly if the caller
+isn't using lexical warnings.
=item *
=item *
+mkdir() now ignores trailing slashes in the directory name,
+as mandated by POSIX.
+
+=item *
+
+Some versions of glibc have a broken modfl(). This affects builds
+with C<-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.
+
+=item *
+
Modulus of unsigned numbers now works (4063328477 % 65535 used to
return 27406, instead of 27047).
=item *
-our() variables will not cause "will not stay shared" warnings.
+Numeric conversions did not recognize changes in the string value
+properly in certain circumstances.
=item *
-pack "Z" now correctly terminates the string with "\0".
+Attributes (like :shared) didn't work with our().
=item *
-Fix password routines which in some shadow password platforms
-(e.g. HP-UX) caused getpwent() to return every other entry.
+our() variables will not cause "will not stay shared" warnings.
=item *
-printf() no longer resets the numeric locale to "C".
+"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.
=item *
-C<q(a\\b)> now parses correctly as C<'a\\b'>.
+pack "Z" now correctly terminates the string with "\0".
=item *
-Printing quads (64-bit integers) with printf/sprintf now works
-without the q L ll prefixes (assuming you are on a quad-capable platform).
+Fix password routines which in some shadow password platforms
+(e.g. HP-UX) caused getpwent() to return every other entry.
=item *
-Regular expressions on references and overloaded scalars now work.
+The PERL5OPT environment variable (for passing command line arguments
+to Perl) didn't work for more than a single group of options.
=item *
-scalar() now forces scalar context even when used in void context.
+PERL5OPT with embedded spaces didn't work.
=item *
-sort() arguments are now compiled in the right wantarray context
-(they were accidentally using the context of the sort() itself).
+printf() no longer resets the numeric locale to "C".
=item *
-Changed the POSIX character class C<[[:space:]]> to include the (very
-rare) vertical tab character. Added a new POSIX-ish character class
-C<[[:blank:]]> which stands for horizontal whitespace (currently,
-the space and the tab).
+C<qw(a\\b)> now parses correctly as C<'a\\b'>.
=item *
-$AUTOLOAD, sort(), lock(), and spawning subprocesses
-in multiple threads simultaneously are now thread-safe.
+pos() did not return the correct value within s///ge in earlier
+versions. This is now handled correctly.
=item *
-Allow read-only string on left hand side of non-modifying tr///.
+Printing quads (64-bit integers) with printf/sprintf now works
+without the q L ll prefixes (assuming you are on a quad-capable platform).
=item *
-Several Unicode fixes (but still not perfect).
-
-=over 8
+Regular expressions on references and overloaded scalars now work.
=item *
-BOMs (byte order marks) in the beginning of Perl files
-(scripts, modules) should now be transparently skipped.
-UTF-16 (UCS-2) encoded Perl files should now be read correctly.
+Right-hand side magic (GMAGIC) could in many cases such as string
+concatenation be invoked too many times.
=item *
-The character tables have been updated to Unicode 3.0.1.
+scalar() now forces scalar context even when used in void context.
=item *
-chr() for values greater than 127 now create utf8 when under use
-utf8.
+SOCKS support is now much more robust.
=item *
-Comparing with utf8 data does not magically upgrade non-utf8 data into
-utf8.
+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.
=item *
-C<IsAlnum>, C<IsAlpha>, and C<IsWord> now match titlecase.
+Changed the POSIX character class C<[[:space:]]> to include the (very
+rarely used) vertical tab character. Added a new POSIX-ish character
+class C<[[:blank:]]> which stands for horizontal whitespace
+(currently, the space and the tab).
=item *
-Concatenation with the C<.> operator or via variable interpolation,
-C<eq>, C<substr>, C<reverse>, C<quotemeta>, the C<x> operator,
-substitution with C<s///>, single-quoted UTF8, should now work--in
-theory.
+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.
=item *
-The C<tr///> operator now works I<slightly> better but is still rather
-broken. Note that the C<tr///CU> functionality has been removed (but
-see pack('U0', ...)).
+Some cases of inconsistent taint propagation (such as within hash
+values) have been fixed.
=item *
-vec() now refuses to deal with characters >255.
+The RE engine found in Perl 5.6.0 accidentally pessimised certain kinds
+of simple pattern matches. These are now handled better.
=item *
-Zero entries were missing from the Unicode classes like C<IsDigit>.
+Regular expression debug output (whether through C<use re 'debug'>
+or via C<-Dr>) now looks better.
-=back
+=item *
+
+Multi-line matches like C<"a\nxb\n" =~ /(?!\A)x/m> were flawed. The
+bug has been fixed.
=item *
-UNIVERSAL::isa no longer caches methods incorrectly. (This broke
-the Tk extension with 5.6.0.)
+Use of $& could trigger a core dump under some situations. This
+is now avoided.
=item *
-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.
+The regular expression captured submatches ($1, $2, ...) are now
+more consistently unset if the match fails, instead of leaving false
+data lying around in them.
=item *
-Some new Configure symbols, useful for extension writers:
+readline() on files opened in "slurp" mode could return an extra "" at
+the end in certain situations. This has been corrected.
-=over 8
+=item *
-=item d_cmsghdr
+Autovivification of symbolic references of special variables described
+in L<perlvar> (as in C<${$num}>) was accidentally disabled. This works
+again now.
-For struct cmsghdr.
+=item *
-=item d_fcntl_can_lock
+Sys::Syslog ignored the C<LOG_AUTH> constant.
-Whether fcntl() can be used for file locking.
+=item *
-=item d_fsync
+All but the first argument of the IO syswrite() method are now optional.
-=item d_getitimer
+=item *
-=item d_getpagsz
+$AUTOLOAD, sort(), lock(), and spawning subprocesses
+in multiple threads simultaneously are now thread-safe.
-For getpagesize(), though you should prefer POSIX::sysconf(_SC_PAGE_SIZE))
+=item *
-=item d_msghdr_s
+Tie::ARRAY SPLICE method was broken.
-For struct msghdr.
+=item *
-=item need_va_copy
+Allow read-only string on left hand side of non-modifying tr///.
-Whether one needs to use Perl_va_copy() to copy varargs.
+=item *
-=item d_readv
+Several Unicode fixes.
-=item d_recvmsg
+=over 8
-=item d_sendmsg
+=item *
-=item sig_size
+BOMs (byte order marks) in the beginning of Perl files
+(scripts, modules) should now be transparently skipped.
+UTF-16 (UCS-2) encoded Perl files should now be read correctly.
-The number of elements in an array needed to hold all the available signals.
+=item *
-=item d_sockatmark
+The character tables have been updated to Unicode 3.1.1.
-=item d_strtoq
+=item *
-=item d_u32align
+Comparing with utf8 data does not magically upgrade non-utf8 data
+into utf8.
-Whether one needs to access character data aligned by U32 sized pointers.
+=item *
-=item d_ualarm
+C<IsAlnum>, C<IsAlpha>, and C<IsWord> now match titlecase.
-=item d_usleep
+=item *
-=back
+Concatenation with the C<.> operator or via variable interpolation,
+C<eq>, C<substr>, C<reverse>, C<quotemeta>, the C<x> operator,
+substitution with C<s///>, single-quoted UTF8, should now work.
=item *
-Removed Configure symbols: the PDP-11 memory model settings: huge,
-large, medium, models.
+The C<tr///> operator now works. Note that the C<tr///CU>
+functionality has been removed (but see pack('U0', ...)).
=item *
-SOCKS support is now much more robust.
+C<eval "v200"> now works.
=item *
-If your file system supports symbolic links you can build Perl outside
-of the source directory by
+Perl 5.6.0 parsed m/\x{ab}/ incorrectly, leading to spurious warnings.
+This has been corrected.
- mkdir /tmp/perl/build/directory
- cd /tmp/perl/build/directory
- sh /path/to/perl/source/Configure -Dmksymlinks ...
+=item *
-This will create in /tmp/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
+Zero entries were missing from the Unicode classes like C<IsDigit>.
- make all test
+=back
-and Perl will be built and tested, all in /tmp/perl/build/directory.
+=item *
+
+Large unsigned numbers (those above 2**31) could sometimes lose their
+unsignedness, causing bogus results in arithmetic operations.
=back
All BSDs
-Setting C<$0> now works (as much as possible; see perlvar for details).
+Setting C<$0> now works (as much as possible; see L<perlvar> for details).
=item *
=item *
+Previously DYNIX/ptx had problems in its Configure probe for non-blocking I/O.
+
+=item *
+
EPOC
EPOC update after Perl 5.6.0. See README.epoc.
Linux
+=over 8
+
+=item *
+
Long doubles should now work (see INSTALL).
=item *
+Linux previously had problems related to sockaddrlen when using
+accept(), revcfrom() (in Perl: recv()), getpeername(), and getsockname().
+
+=back
+
+=item *
+
MacOS Classic
Compilation of the standard Perl distribution in MacOS Classic should
VMS
-chdir() now works better despite a CRT bug; now works with MULTIPLICITY
-(see INSTALL); now works with Perl's malloc.
-
-=item *
-
-Windows
-
-=over 8
-
-=item *
-
-accept() no longer leaks memory.
-
-=item *
-
-Better chdir() return value for a non-existent directory.
-
-=item *
-
-New %ENV entries now propagate to subprocesses.
-
-=item *
-
-$ENV{LIB} now used to search for libs under Visual C.
-
-=item *
-
-A failed (pseudo)fork now returns undef and sets errno to EAGAIN.
-
-=item *
-
-Allow REG_EXPAND_SZ keys in the registry.
-
-=item *
-
-Can now send() from all threads, not just the first one.
-
-=item *
-
-Fake signal handling reenabled, bugs and all.
-
-=item *
-
-Less stack reserved per thread so that more threads can run
-concurrently. (Still 16M per thread.)
-
-=item *
-
-C<File::Spec->tmpdir()> now prefers C:/temp over /tmp
-(works better when perl is running as service).
-
-=item *
-
-Better UNC path handling under ithreads.
-
-=item *
-
-wait() and waitpid() now work much better.
-
-=item *
-
-winsock handle leak fixed.
-
-=back
-
-=back
-
-=head1 New or Changed Diagnostics
-
-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.
-
-The various "opened only for", "on closed", "never opened" warnings
-drop the C<main::> prefix for filehandles in the C<main> package,
-for example C<STDIN> instead of <main::STDIN>.
-
-The "Unrecognized escape" warning has been extended to include C<\8>,
-C<\9>, and C<\_>. There is no need to escape any of the C<\w> characters.
+chdir() now works better despite a CRT bug; now works with MULTIPLICITY
+(see INSTALL); now works with Perl's malloc.
-=over 4
+The tainting of C<%ENV> elements via C<keys> or C<values> was previously
+unimplemented. It now works as documented.
-Two new debugging options have been added: if you have compiled your
-Perl with debugging, you can use the -DT and -DR options to trace
-tokenising and to add reference counts to displaying variables,
-respectively.
+The C<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. The most significant enhancement is that we can now
+usually get the completion status of a terminated process.
-=item *
+POSIX-style signals are now emulated much better on VMS versions prior
+to 7.0.
-If an attempt to use a (non-blessed) reference as an array index
-is made, a warning is given.
+The C<system> function and backticks operator have improved
+functionality and better error handling.
=item *
-C<push @a;> and C<unshift @a;> (with no values to push or unshift)
-now give a warning. This may be a problem for generated and evaled
-code.
+Windows
-=back
+=over 8
-=head1 Changed Internals
+=item *
-=over 4
+accept() no longer leaks memory.
=item *
-perlapi.pod (a companion to perlguts) now attempts to document the
-internal API.
+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++).
=item *
-You can now build a really minimal perl called microperl.
-Building microperl does not require even running Configure;
-C<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.
+Better chdir() return value for a non-existent directory.
=item *
-Added rsignal(), whichsig(), do_join() to the publicised API.
+Duping socket handles with open(F, ">&MYSOCK") now works under Windows 9x.
=item *
-Made possible to propagate customised exceptions via croak()ing.
+New %ENV entries now propagate to subprocesses.
=item *
-Added is_utf8_char(), is_utf8_string(), bytes_to_utf8(), and utf8_to_bytes().
+Current directory entries in %ENV are now correctly propagated to child
+processes.
=item *
-Now xsubs can have attributes just like subs.
+$ENV{LIB} now used to search for libs under Visual C.
=item *
-Some new APIs: ptr_table_clear(), ptr_table_free(), sv_setref_uv().
-For the full list of the available APIs see L<perlapi>.
+fork() emulation has been improved in various ways, but still continues
+to be experimental. See L<perlfork> for known bugs and caveats.
=item *
-dTHR and djSP have been obsoleted; the former removed (because it's
-a no-op) and the latter replaced with dSP.
+A failed (pseudo)fork now returns undef and sets errno to EAGAIN.
=item *
-Perl now uses system malloc instead of Perl malloc on all 64-bit
-platforms, and even in some not-always-64-bit platforms like AIX,
-IRIX, and Solaris. This change breaks backward compatibility but
-Perl's malloc has problems with large address spaces and also the
-speed of vendors' malloc is generally better in large address space
-machines (Perl's malloc is mostly tuned for space).
-
-=back
+Win32::GetCwd() correctly returns C:\ instead of C: when at the drive root.
+Other bugs in chdir() and Cwd::cwd() have also been fixed.
-=head1 Security Vulnerability Closed
+=item *
-(This change was already made in 5.7.0 but bears repeating here.)
+HTML files will be installed in c:\perl\html instead of c:\perl\lib\pod\html
-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 http://www.cpan.org/src/5.0/sperl-2000-08-05/sperl-2000-08-05.txt
-for more information.
+=item *
-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 makefiles now provide a single switch to bulk-enable all the features
+enabled in ActiveState ActivePerl (a popular Win32 binary distribution).
-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 code is being reviewed
-and if deemed too risky to continue to be supported, it may be
-completely removed from future releases. 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 http://www.courtesan.com/sudo/).
+=item *
-=head1 Selected Bug Fixes
+Allow REG_EXPAND_SZ keys in the registry.
-Numerous memory leaks and uninitialized memory accesses have been hunted down.
-Most importantly anonymous subs used to leak quite a bit.
+=item *
-=over 4
+Can now send() from all threads, not just the first one.
=item *
-chop(@list) in list context returned the characters chopped in
-reverse order. This has been reversed to be in the right order.
+Fake signal handling reenabled, bugs and all.
=item *
-The order of DESTROYs has been made more predictable.
+%SIG has been enabled under USE_ITHREADS, but its use is completely
+unsupported under all configurations.
=item *
-mkdir() now ignores trailing slashes in the directory name,
-as mandated by POSIX.
+Less stack reserved per thread so that more threads can run
+concurrently. (Still 16M per thread.)
=item *
-Attributes (like :shared) didn't work with our().
+C<File::Spec->tmpdir()> now prefers C:/temp over /tmp
+(works better when perl is running as service).
=item *
-The PERL5OPT environment variable (for passing command line arguments
-to Perl) didn't work for more than a single group of options.
+Better UNC path handling under ithreads.
=item *
-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.
+wait(), waitpid() and backticks now return the correct exit status under
+Windows 9x.
=item *
-All but the first argument of the IO syswrite() method are now optional.
+winsock handle leak fixed.
-=item *
+=back
-Tie::ARRAY SPLICE method was broken.
+=back
+
+=head1 New or Changed Diagnostics
+
+=over 4
=item *
-vec() now tries to work with characters <= 255 when possible, but it leaves
-higher character values in place. In that case, if vec() was used to modify
-the string, it is no longer considered to be utf8-encoded.
+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 C<E<lt>-- HERE> marker.
=item *
-The autouse pragma didn't work for Multi::Part::Function::Names.
+The various "opened only for", "on closed", "never opened" warnings
+drop the C<main::> prefix for filehandles in the C<main> package,
+for example C<STDIN> instead of C<main::STDIN>.
=item *
-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 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.
+The "Unrecognized escape" warning has been extended to include C<\8>,
+C<\9>, and C<\_>. There is no need to escape any of the C<\w> characters.
=item *
-L<dprofpp> -R didn't work.
+Two new debugging options have been added: if you have compiled your
+Perl with debugging, you can use the -DT and -DR options to trace
+tokenising and to add reference counts to displaying variables,
+respectively.
=item *
-PERL5OPT with embedded spaces didn't work.
+If an attempt to use a (non-blessed) reference as an array index
+is made, a warning is given.
=item *
-L<Sys::Syslog> ignored the C<LOG_AUTH> constant.
+C<push @a;> and C<unshift @a;> (with no values to push or unshift)
+now give a warning. This may be a problem for generated and evaled
+code.
-=back
+=item *
-=head2 Platform Specific Changes and Fixes
+If you try to L<perlfunc/pack> a number less than 0 or larger than 255
+using the C<"C"> format you will get an optional warning. Similarly
+for the C<"c"> format and a number less than -128 or more than 127.
-=over 4
+=item *
+
+Certain regex modifiers such as C<(?o)> make sense only if applied to
+the entire regex. You will an optional warning if you try to do otherwise.
=item *
-Some versions of glibc have a broken modfl(). This affects builds
-with C<-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.
+Using arrays or hashes as references (e.g. C<< %foo->{bar} >>
+has been deprecated for a while. Now you will get an optional warning.
=back
-=head2 Platform Specific Changes and Fixes
+=head1 Changed Internals
=over 4
=item *
-Linux previously had problems related to sockaddrlen when using
-accept(), revcfrom() (in Perl: recv()), getpeername(), and getsockname().
+perlapi.pod (a companion to perlguts) now attempts to document the
+internal API.
=item *
-Previously DYNIX/ptx had problems in its Configure probe for non-blocking I/O.
+You can now build a really minimal perl called microperl.
+Building microperl does not require even running Configure;
+C<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.
=item *
-Windows
-
-=over 8
+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 L<perlapi>.
=item *
-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++).
+Made possible to propagate customised exceptions via croak()ing.
=item *
-Win32::GetCwd() correctly returns C:\ instead of C: when at the drive root.
-Other bugs in chdir() and Cwd::cwd() have also been fixed.
+Now xsubs can have attributes just like subs. (Well, at least the
+built-in attributes.)
=item *
-Duping socket handles with open(F, ">&MYSOCK") now works under Windows 9x.
+dTHR and djSP have been obsoleted; the former removed (because it's
+a no-op) and the latter replaced with dSP.
=item *
-HTML files will be installed in c:\perl\html instead of c:\perl\lib\pod\html
+PERL_OBJECT has been completely removed.
=item *
-The makefiles now provide a single switch to bulk-enable all the features
-enabled in ActiveState ActivePerl (a popular binary distribution).
-
-=back
-
-=head1 New Tests
-
-Several new tests have been added, especially for the F<lib> subsection.
-
-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.)
+The MAGIC constants (e.g. C<'P'>) have been macrofied
+(e.g. C<PERL_MAGIC_TIED>) for better source code readability
+and maintainability.
-=head1 New or Changed Diagnostics
+=item *
-=over 4
+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
+C<offsets> member of the C<struct regexp>. See L<perldebguts> for more
+complete information.
=item *
-In the regular expression diagnostics the C<E<lt>E<lt> HERE> marker
-introduced in 5.7.0 has been changed to be C<E<lt>-- HERE> since too
-many people found the C<E<lt>E<lt>> to be too similar to here-document
-starters.
+The C code has been made much more C<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.
=item *
-If you try to L<perlfunc/pack> a number less than 0 or larger than 255
-using the C<"C"> format you will get an optional warning. Similarly
-for the C<"c"> format and a number less than -128 or more than 127.
+F<perly.c>, F<sv.c>, and F<sv.h> have now been extensively commented.
=item *
-Certain regex modifiers such as C<(?o)> make sense only if applied to
-the entire regex. You will an optional warning if you try to do otherwise.
+Documentation on how to use the Perl source repository has been added
+to F<Porting/repository.pod>.
=item *
-Using arrays or hashes as references (e.g. C<%foo->{bar}> has been
-deprecated for a while. Now you will get an optional warning.
+There are now several profiling make targets.
=back
-=head1 Source Code Enhancements
+=head1 Security Vulnerability Closed
-=head2 MAGIC constants
+(This change was already made in 5.7.0 but bears repeating here.)
-The MAGIC constants (e.g. C<'P'>) have been macrofied
-(e.g. C<PERL_MAGIC_TIED>) for better source code readability
-and maintainability.
+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 http://www.cpan.org/src/5.0/sperl-2000-08-05/sperl-2000-08-05.txt
+for more information.
-=head2 Better commented code
+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.
-F<perly.c>, F<sv.c>, and F<sv.h> have now been extensively commented.
+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 http://www.courtesan.com/sudo/).
-=head2 Regex pre-/post-compilation items matched up
+=head1 New Tests
-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
-C<offsets> member of the C<struct regexp>. See L<perldebguts> for more
-complete information.
+Several new tests have been added, especially for the F<lib>
+subsection. There are now about 34 000 individual tests (spread over
+about 530 test scripts), in the regression suite (5.6.1 has about
+11700 tests, in 258 test scripts) Many of the new tests are introduced
+by the new modules, but still in general Perl is now more thoroughly
+tested.
-=head2 gcc -Wall
+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. In a really
+fast machine you can hope to finish the suite in about 5 minutes
+(wallclock time).
-The C code has been made much more C<gcc -Wall> clean. Some warning
-messages still remain, though, so if you are compiling with gcc you
-will see some warnings about dubious practices. The warnings are
-being worked on.
+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.)
=head1 Known Problems
-Note that unlike other sections in this document (which describe
-changes since 5.7.0) this section is cumulative containing known
-problems for all the 5.7 releases.
-
=head2 AIX
=over 4
=head2 Amiga Perl Invoking Mystery
One cannot call Perl using the C<volume:> syntax, that is, C<perl -v>
-works, but for example C<bin:perl -v> doesn't. The exact reason is
+works, but for example C<bin:perl -v> doesn't. The exact reason isn't
known but the current suspect is the F<ixemul> library.
=head2 lib/ftmp-security tests warn 'system possibly insecure'
No known fix.
+=head2 Mac OS X
+
+The following tests are known to fail:
+
+ 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
+ ../ext/POSIX/t/posix.t 31 1 3.23% 10
+ ../lib/warnings.t 450 1 0.22% 316
+
=head2 OS/390
OS/390 has rather many test failures but the situation is actually
=head2 Failure of Thread tests
-B<Note that support for 5.005-style threading remains experimental.>
+B<Note that support for 5.005-style threading remains experimental
+and practically unsupported.>
The following tests are known to fail due to fundamental problems in
the 5.005 threading implementation. These are not new failures--Perl
5.005_0x has the same bugs, but didn't have these tests.
- lib/autouse.t 4
- t/lib/thr5005.t 19-20
+ ext/List/Util/t/first 2
+ lib/autouse 4
+ ext/Thread/thr5005 19-20
+
+These failures are unlikely to get fixed.
=head2 UNICOS
=head2 VMS
-Rather many tests are failing in VMS but that actually more tests
-succeed in VMS than they used to, it's just that there are many,
-many more tests than there used to be.
-
-Here are the known failures from some compiler/platform combinations.
-
-DEC C V5.3-006 on OpenVMS VAX V6.2
+There is one known test failure with a default configuration:
- [-.ext.list.util.t]tainted..............FAILED on test 3
- [-.ext.posix]sigaction..................FAILED on test 7
- [-.ext.time.hires]hires.................FAILED on test 14
- [-.lib.file.find]taint..................FAILED on test 17
- [-.lib.math.bigint.t]bigintpm...........FAILED on test 1183
- [-.lib.test.simple.t]exit...............FAILED on test 1
- [.lib]vmsish............................FAILED on test 13
- [.op]sprintf............................FAILED on test 12
- Failed 8/399 tests, 91.23% okay.
-
-DEC C V6.0-001 on OpenVMS Alpha V7.2-1 and
-Compaq C V6.2-008 on OpenVMS Alpha V7.1
-
- [-.ext.list.util.t]tainted..............FAILED on test 3
- [-.lib.file.find]taint..................FAILED on test 17
- [-.lib.test.simple.t]exit...............FAILED on test 1
- [.lib]vmsish............................FAILED on test 13
- Failed 4/399 tests, 92.48% okay.
-
-Compaq C V6.4-005 on OpenVMS Alpha 7.2.1
-
- [-.ext.b]showlex........................FAILED on test 1
- [-.ext.list.util.t]tainted..............FAILED on test 3
- [-.lib.file.find]taint..................FAILED on test 17
- [-.lib.test.simple.t]exit...............FAILED on test 1
- [.lib]vmsish............................FAILED on test 13
- [.op]misc...............................FAILED on test 49
- Failed 6/401 tests, 92.77% okay.
-
+ [.run]switches..........................FAILED on test 1
+
=head2 Win32
In multi-CPU boxes there are some problems with the I/O buffering:
Code like the above is known to leak memory every time the local()
is executed.
+=head2 Localising Tied Arrays and Hashes Is Broken
+
+ local %tied_array;
+
+doesn't work as one would expect: the old value is restored
+incorrectly.
+
=head2 Self-tying of Arrays and Hashes Is Forbidden
Self-tying of arrays and hashes is broken in rather deep and
frustrated at the mysterious results (core dumps, most often) it is
for now forbidden (you will get a fatal error even from an attempt).
-=head2 Variable Attributes are not Currently Usable for Tieing
-
-This limitation will hopefully be fixed in future. (Subroutine
-attributes work fine for tieing, see L<Attribute::Handlers>).
-
=head2 Building Extensions Can Fail Because Of Largefiles
Some extensions like mod_perl are known to have issues with
all binaries with different ideas about file offsets, all this is
platform-dependent.
+=head2 Unicode Support on EBCDIC Still Spotty
+
+Though mostly working, Unicode support still has problem spots on
+EBCDIC platforms. One such known spot are the C<\p{}> and C<\P{}>
+regular expression constructs for code points less than 256: the
+pP are testing for Unicode code points, not knowing about EBCDIC.
+
=head2 The Compiler Suite Is Still Experimental
-The compiler suite is slowly getting better but is nowhere near
-working order yet.
+The compiler suite is slowly getting better but it continues to be
+highly experimental. Use in production environments is discouraged.
-=head2 The Long Double Support is Still Experimental
+=head2 The Long Double Support Is Still Experimental
The ability to configure Perl's numbers to use "long doubles",
floating point numbers of hopefully better accuracy, is still
operations are more likely to be executed by less optimised
libraries).
+=head2 Seen In Perl 5.7 But Gone Now
+
+Some modules were seen in the Perl 5.7 development releases
+but are not present in 5.8.0.
+
+=over 4
+
+=item *
+
+C<Attribute::Handlers> was removed because the implementation of C<my>
+variable attributes changed so much that the Attribute::Handlers will
+require a major rewrite. (This means that you can't use
+Attribute::Handler 0.76 with Perl 5.8.0.)
+
+=item *
+
+C<Time::Piece> (previously known as C<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.
+
+=back
+
=head1 Reporting Bugs
If you find what you think is a bug, you might check the articles
projects / p5sagit/p5-mst-13.2.git / blobdiff