=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 Security Vulnerability Closed
+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.
-A potential security vulnerability in the optional suidperl component
-of Perl has been identified. suidperl is neither built nor installed
-by default. As of September the 2nd, 2000, the only known vulnerable
-platform is Linux, most likely all Linux distributions. CERT and
-various vendors have been alerted about the vulnerability.
+If you are upgrading from Perl 5.005_03, you might also want
+to read L<perl56delta>.
-The problem was caused by Perl trying to report a suspected security
-exploit attempt using an external program, /bin/mail. On Linux
-platforms the /bin/mail program had an undocumented feature which
-when combined with suidperl gave access to a root shell, resulting in
-a serious compromise instead of reporting the exploit attempt. If you
-don't have /bin/mail, or if you have 'safe setuid scripts', or if
-suidperl is not installed, you are safe.
-
-The exploit attempt reporting feature has been completely removed from
-the Perl 5.7.0 release, 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/).
-
-=head1 Incompatible Changes
+=head1 Highlights In 5.8.0
=over 4
=item *
-Arrays now always interpolate into double-quoted strings:
-constructs like "foo@bar" now always assume C<@bar> is an array,
-whether or not the compiler has seen use of C<@bar>.
-
-=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.
+Better Unicode support
=item *
-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.
+New Thread Implementation
=item *
-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.
+Many New Modules
=item *
-lstat(FILEHANDLE) now gives a warning because the operation makes no sense.
-In future releases this may become a fatal error.
+Better Numeric Accuracy
=item *
-The long deprecated uppercase aliases for the string comparison
-operators (EQ, NE, LT, LE, GE, GT) have now been removed.
-
-=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.
+Safe Signals
=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', ...).
+More Extensive Regression Testing
=back
-=head1 Core Enhancements
-
-=over 4
-
-=item *
-
-C<perl -d:Module=arg,arg,arg> now works (previously one couldn't pass
-in multiple arguments.)
-
-=item *
-
-my __PACKAGE__ $obj now works.
-
-=item *
-
-C<no Module;> now works even if there is no "sub unimport" in the Module.
+=head1 Incompatible Changes
-=item *
+=head2 64-bit platforms and malloc
-The numerical comparison operators return C<undef> if either operand
-is a NaN. Previously the behaviour was unspecified.
+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.
-=item *
+=head2 AIX Dynaloading
-C<pack('U0a*', ...)> can now be used to force a string to UTF8.
+The AIX dynaloading now uses in AIX releases 4.3 and newer the native
+dlopen interface of AIX instead of the old emulated interface. This
+change will probably break backward compatibility with compiled
+modules. The change was made to make Perl more compliant with other
+applications like modperl which are using the AIX native interface.
-=item *
+=head2 Socket Extension Dynamic in VMS
-prototype(\&) is now available.
+The Socket extension is now dynamically loaded instead of being
+statically built in. This may or may not be a problem with ancient
+TCP/IP stacks of VMS: we do not know since we weren't able to test
+Perl in such configurations.
-=item *
+=head2 IEEE-format Floating Point Default on OpenVMS Alpha
-There is now an UNTIE method.
+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.
-=back
+=head2 Different Definition of the Unicode Character Classes \p{In...}
-=head1 Modules and Pragmata
+As suggested by the Unicode consortium, the Unicode character classes
+now prefer I<scripts> as opposed to I<blocks> (as defined by Unicode);
+in Perl, when the C<\p{In....}> and the C<\p{In....}> regular expression
+constructs are used. This has changed the definition of some of those
+character classes.
-=head2 New Modules
+The difference between scripts and blocks is that scripts are the
+glyphs used by a language or a group of languages, while the blocks
+are more artificial groupings of 256 characters based on the Unicode
+numbering.
-=over 4
+In general this change results in more inclusive Unicode character
+classes, but changes to the other direction also do take place:
+for example while the script C<Latin> includes all the Latin
+characters and their various diacritic-adorned versions, it
+does not include the various punctuation or digits (since they
+are not solely C<Latin>).
-=item *
+Changes in the character class semantics may have happened if a script
+and a block happen to have the same name, for example C<Hebrew>.
+In such cases the script wins and C<\p{InHebrew}> now means the script
+definition of Hebrew. The block definition in still available,
+though, by appending C<Block> to the name: C<\p{InHebrewBlock}> means
+what C<\p{InHebrew}> meant in perl 5.6.0. For the full list
+of affected character classes, see L<perlunicode/Blocks>.
-File::Temp allows one to create temporary files and directories in an
-easy, portable, and secure way.
+=head2 Perl Parser Stress Tested
-=item *
+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.
-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.
+=head2 REF(...) Instead Of SCALAR(...)
-=back
+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 Updated And Improved Modules and Pragmata
+=head2 Deprecations
=over 4
=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.
+The semantics of bless(REF, REF) were unclear and until someone proves
+it to make some sense, it is forbidden.
=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.
+The obsolete chat2 library that should never have been allowed
+to escape the laboratory has been decommissioned.
=item *
-The attributes::reftype() now works on tied arguments.
+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 *
-AutoLoader can now be disabled with C<no AutoLoader;>,
+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 *
-The English module can now be used without the infamous performance
-hit by saying
-
- use English '-no_performance_hit';
-
-(Assuming, of course, that one doesn't need the troublesome variables
-C<$`>, C<$&>, or C<$'>.) Also, introduced C<@LAST_MATCH_START> and
-C<@LAST_MATCH_END> English aliases for C<@-> and C<@+>.
+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 *
-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.
+Spurious syntax errors generated in certain situations, when glob()
+caused File::Glob to be loaded for the first time, have been fixed.
=item *
-File::Glob::glob() renamed to File::Glob::bsd_glob() to avoid
-prototype mismatch with CORE::glob().
+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 *
-IPC::Open3 now allows the use of numeric file descriptors.
+lstat(FILEHANDLE) now gives a warning because the operation makes no sense.
+In future releases this may become a fatal error.
=item *
-use lib now works identically to @INC. Removing directories
-with 'no lib' now works.
+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 *
-C<%INC> now localised in a Safe compartment so that use/require work.
+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 *
-The Shell module now has an OO interface.
-
-=back
-
-=head1 Utility Changes
-
-=over 4
+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.
=item *
-The Emacs perl mode (emacs/cperl-mode.el) has been updated to version
-4.31.
+The syntaxes C<< @a->[...] >> and C<< %h->{...} >> have now been deprecated.
=item *
-Perlbug is now much more robust. It also sends the bug report to
-perl.org, not perl.com.
+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 perlcc utility has been rewritten and its user interface (that is,
-command line) is much more like that of the UNIX C compiler, cc.
+The long deprecated uppercase aliases for the string comparison
+operators (EQ, NE, LT, LE, GE, GT) have now been removed.
=item *
-The xsubpp utility for extension writers now understands POD
-documentation embedded in the *.xs files.
+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 New Documentation
-
-=over 4
-
-=item *
-
-perl56delta details the changes between the 5.005 release and the
-5.6.0 release.
-
-=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.
-
-=item *
-
-perlposix-bc explains using Perl on the POSIX-BC platform
-(an EBCDIC mainframe platform).
-
-=item *
-
-perlretut is a regular expression tutorial.
-
-=item *
-
-perlrequick is a regular expressions quick-start guide.
-Yes, much quicker than perlretut.
-
-=item *
-
-perlutil explains the command line utilities packaged with the Perl
-distribution.
-
-=back
+=head1 Core Enhancements
-=head1 Performance Enhancements
+=head2 PerlIO is Now The Default
=over 4
=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).
+IO is now by default done via PerlIO rather than system's "stdio".
+PerlIO allows "layers" to be "pushed" onto a file handle to alter the
+handle's behaviour. Layers can be specified at open time via 3-arg
+form of open:
-=back
+ open($fh,'>:crlf :utf8', $path) || ...
-=head1 Installation and Configuration Improvements
+or on already opened handles via extended C<binmode>:
-=head2 Generic Improvements
+ binmode($fh,':encoding(iso-8859-7)');
-=over 4
+The built-in layers are: unix (low level read/write), stdio (as in
+previous Perls), perlio (re-implementation of stdio buffering in a
+portable manner), crlf (does CRLF <=> "\n" translation as on Win32,
+but available on any platform). A mmap layer may be available if
+platform supports it (mostly UNIXes).
-=item *
+Layers to be applied by default may be specified via the 'open' pragma.
-INSTALL now explains how you can configure Perl to use 64-bit
-integers even on non-64-bit platforms.
+See L</"Installation and Configuration Improvements"> for the effects
+of PerlIO on your architecture name.
=item *
-Policy.sh policy change: if you are reusing a Policy.sh file
-(see INSTALL) and you use Configure -Dprefix=/foo/bar and in the old
-Policy $prefix eq $siteprefix and $prefix eq $vendorprefix, all of
-them will now be changed to the new prefix, /foo/bar. (Previously
-only $prefix changed.) If you do not like this new behaviour,
-specify prefix, siteprefix, and vendorprefix explicitly.
+File handles can be marked as accepting Perl's internal encoding of Unicode
+(UTF-8 or UTF-EBCDIC depending on platform) by a pseudo layer ":utf8" :
-=item *
+ open($fh,">:utf8","Uni.txt");
-A new optional location for Perl libraries, otherlibdirs, is available.
-It can be used for example for vendor add-ons without disturbing Perl's
-own library directories.
+Note for EBCDIC users: the pseudo layer ":utf8" is erroneously named
+for you since it's not UTF-8 what you will be getting but instead
+UTF-EBCDIC. See L<perlunicode>, L<utf8>, and
+http://www.unicode.org/unicode/reports/tr16/ for more information.
+In future releases this naming may change.
=item *
-In many platforms the vendor-supplied 'cc' is too stripped-down to
-build Perl (basically, 'cc' doesn't do ANSI C). If this seems
-to be the case and 'cc' does not seem to be the GNU C compiler
-'gcc', an automatic attempt is made to find and use 'gcc' instead.
+File handles can translate character encodings from/to Perl's internal
+Unicode form on read/write via the ":encoding()" layer.
=item *
-gcc needs to closely track the operating system release to avoid
-build problems. If Configure finds that gcc was built for a different
-operating system release than is running, it now gives a clearly visible
-warning that there may be trouble ahead.
-
-=item *
+File handles can be opened to "in memory" files held in Perl scalars via:
-If binary compatibility with the 5.005 release is not wanted, Configure
-no longer suggests including the 5.005 modules in @INC.
+ open($fh,'>', \$variable) || ...
=item *
-Configure C<-S> can now run non-interactively.
+Anonymous temporary files are available without need to
+'use FileHandle' or other module via
-=item *
+ open($fh,"+>", undef) || ...
-configure.gnu now works with options with whitespace in them.
+That is a literal undef, not an undefined value.
=item *
-installperl now outputs everything to STDERR.
+The list form of C<open> is now implemented for pipes (at least on UNIX):
-=item *
+ open($fh,"-|", 'cat', '/etc/motd')
-$Config{byteorder} is now computed dynamically (this is more robust
-with "fat binaries" where an executable image contains binaries for
-more than one binary platform.)
+creates a pipe, and runs the equivalent of exec('cat', '/etc/motd') in
+the child process.
=back
-=head1 Selected Bug Fixes
-
-=over 4
-
-=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<$.> no longer gets corrupted, all debugger output now
-goes correctly to the socket if RemotePort is set.
-
-=item *
-
-C<*foo{FORMAT}> now works.
-
-=item *
-
-Lexical warnings now propagating correctly between scopes.
-
-=item *
-
-Line renumbering with eval and C<#line> now works.
-
-=item *
-
-Fixed numerous memory leaks, especially in eval "".
-
-=item *
-
-Modulus of unsigned numbers now works (4063328477 % 65535 used to
-return 27406, instead of 27047).
-
-=item *
-
-Some "not a number" warnings introduced in 5.6.0 eliminated to be
-more compatible with 5.005. Infinity is now recognised as a number.
-
-=item *
-
-our() variables will not cause "will not stay shared" warnings.
-
-=item *
-
-pack "Z" now correctly terminates the string with "\0".
-
-=item *
-
-Fix password routines which in some shadow password platforms
-(e.g. HP-UX) caused getpwent() to return every other entry.
-
-=item *
-
-printf() no longer resets the numeric locale to "C".
-
-=item *
-
-C<q(a\\b)> now parses correctly as C<'a\\b'>.
-
-=item *
-
-Printing quads (64-bit integers) with printf/sprintf now works
-without the q L ll prefixes (assuming you are on a quad-capable platform).
-
-=item *
-
-Regular expressions on references and overloaded scalars now work.
-
-=item *
-
-scalar() now forces scalar context even when used in void context.
-
-=item *
-
-sort() arguments are now compiled in the right wantarray context
-(they were accidentally using the context of the sort() itself).
-
-=item *
-
-Changed the POSIX character class C<[[:space:]]> to include the (very
-rare) vertical tab character. Added a new POSIX-ish character class
-C<[[:blank:]]> which stands for horizontal whitespace (currently,
-the space and the tab).
-
-=item *
-
-$AUTOLOAD, sort(), lock(), and spawning subprocesses
-in multiple threads simultaneously are now thread-safe.
-
-=item *
-
-Allow read-only string on left hand side of non-modifying tr///.
-
-=item *
+=head2 Signals Are Now Safe
-Several Unicode fixes (but still not perfect).
+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.
-=over 8
+=head2 Unicode Overhaul
-=item *
+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.
-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.
+=over 4
=item *
-The character tables have been updated to Unicode 3.0.1.
+The Unicode Character Database coming with Perl has been upgraded
+to Unicode 3.1.1. For more information, see http://www.unicode.org/.
=item *
-chr() for values greater than 127 now create utf8 when under use
-utf8.
+For developers interested in enhancing Perl's Unicode capabilities:
+almost all the UCD files are included with the Perl distribution in
+the lib/unicore subdirectory. The most notable omission, for space
+considerations, is the Unihan database.
=item *
-Comparing with utf8 data does not magically upgrade non-utf8 data into
-utf8.
+The Unicode character classes \p{Blank} and \p{SpacePerl} have been
+added. "Blank" is like C isblank(), that is, it contains only
+"horizontal whitespace" (the space character is, the newline isn't),
+and the "SpacePerl" is the Unicode equivalent of C<\s> (\p{Space}
+isn't, since that includes the vertical tabulator character, whereas
+C<\s> doesn't.)
-=item *
+=back
-C<IsAlnum>, C<IsAlpha>, and C<IsWord> now match titlecase.
+=head2 Understanding of Numbers
-=item *
+In general a lot of fixing has happened in the area of Perl's
+understanding of numbers, both integer and floating point. Since in
+many systems the standard number parsing functions like C<strtoul()>
+and C<atof()> seem to have bugs, Perl tries to work around their
+deficiencies. This results hopefully in more accurate numbers.
-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.
+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.)
-=item *
+=head2 Miscellaneous Enhancements
-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', ...)).
+=over 4
=item *
-vec() now refuses to deal with characters >255.
+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 *
-Zero entries were missing from the Unicode classes like C<IsDigit>.
-
-=back
+C<perl -d:Module=arg,arg,arg> now works (previously one couldn't pass
+in multiple arguments.)
=item *
-UNIVERSAL::isa no longer caches methods incorrectly. (This broke
-the Tk extension with 5.6.0.)
-
-=back
-
-=head2 Platform Specific Changes and Fixes
-
-=over 4
+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 *
-BSDI 4.*
-
-Perl now works on post-4.0 BSD/OSes.
+Formats now support zero-padded decimal fields.
=item *
-All BSDs
-
-Setting C<$0> now works (as much as possible; see perlvar for details).
+Lvalue subroutines can now return C<undef> in list context.
+However, the lvalue subroutine feature still remains experimental.
=item *
-Cygwin
-
-Numerous updates; currently synchronised with Cygwin 1.1.4.
+A new special regular expression variable has been introduced:
+C<$^N>, which contains the most-recently closed group (submatch).
=item *
-EPOC
-
-EPOC update after Perl 5.6.0. See README.epoc.
+C<no Module;> now works even if there is no "sub unimport" in the Module.
=item *
-FreeBSD 3.*
-
-Perl now works on post-3.0 FreeBSDs.
+The numerical comparison operators return C<undef> if either operand
+is a NaN. Previously the behaviour was unspecified.
=item *
-HP-UX
-
-README.hpux updated; C<Configure -Duse64bitall> now almost works.
+The following builtin functions are now overridable: each(), keys(),
+pop(), push(), shift(), splice(), unshift().
=item *
-IRIX
-
-Numerous compilation flag and hint enhancements; accidental mixing
-of 32-bit and 64-bit libraries (a doomed attempt) made much harder.
+C<pack('U0a*', ...)> can now be used to force a string to UTF8.
=item *
-Linux
-
-Long doubles should now work (see INSTALL).
+my __PACKAGE__ $obj now works.
=item *
-MacOS Classic
+The printf() and sprintf() now support parameter reordering using the
+C<%\d+\$> and C<*\d+\$> syntaxes. For example
-Compilation of the standard Perl distribution in MacOS Classic should
-now work if you have the Metrowerks development environment and
-the missing Mac-specific toolkit bits. Contact the macperl mailing
-list for details.
+ print "%2\$s %1\$s\n", "foo", "bar";
-=item *
+will print "bar foo\n". This feature helps in writing
+internationalised software, and in general when the order
+of the parameters can vary.
-MPE/iX
+=item *
-MPE/iX update after Perl 5.6.0. See README.mpeix.
+prototype(\&) is now available.
=item *
-NetBSD/sparc
-
-Perl now works on NetBSD/sparc.
+prototype(\[$@%&]) is now available to implicitly create references
+(useful for example if you want to emulate the tie() interface).
=item *
-OS/2
-
-Now works with usethreads (see INSTALL).
+untie() will now call an UNTIE() hook if it exists. See L<perltie>
+for details.
=item *
-Solaris
-
-64-bitness using the Sun Workshop compiler now works.
+L<utime> now supports C<utime undef, undef, @files> to change the
+file timestamps to the current time.
=item *
-Tru64 (aka Digital UNIX, aka DEC OSF/1)
+The rules for allowing underscores (underbars) in numeric constants
+have been relaxed and simplified: now you can have an underscore
+simply B<between digits>.
-The operating system version letter now recorded in $Config{osvers}.
-Allow compiling with gcc (previously explicitly forbidden). Compiling
-with gcc still not recommended because buggy code results, even with
-gcc 2.95.2.
+=back
-=item *
+=head1 Modules and Pragmata
-Unicos
+=head2 New Modules and Pragmata
-Fixed various alignment problems that lead into core dumps either
-during build or later; no longer dies on math errors at runtime;
-now using full quad integers (64 bits), previously was using
-only 46 bit integers for speed.
+=over 4
=item *
-VMS
+C<Attribute::Handlers> allows a class to define attribute handlers.
-chdir() now works better despite a CRT bug; now works with MULTIPLICITY
-(see INSTALL); now works with Perl's malloc.
+ package MyPack;
+ use Attribute::Handlers;
+ sub Wolf :ATTR(SCALAR) { print "howl!\n" }
-=item *
+ # later, in some package using or inheriting from MyPack...
-Windows
+ my MyPack $Fluffy : Wolf; # the attribute handler Wolf will be called
-=over 8
+Both variables and routines can have attribute handlers. Handlers can
+be specific to type (SCALAR, ARRAY, HASH, or CODE), or specific to the
+exact compilation phase (BEGIN, CHECK, INIT, or END).
=item *
-accept() no longer leaks memory.
+B<B::Concise> is a new compiler backend for walking the Perl syntax
+tree, printing concise info about ops, from Stephen McCamant. The
+output is highly customisable. See L<B::Concise>.
=item *
-Better chdir() return value for a non-existent directory.
+C<Class::ISA> for reporting the search path for a class's ISA tree,
+by Sean Burke, has been added. See L<Class::ISA>.
=item *
-New %ENV entries now propagate to subprocesses.
+C<Cwd> has now a split personality: if possible, an XS extension is
+used, (this will hopefully be faster, more secure, and more robust)
+but if not possible, the familiar Perl implementation is used.
=item *
-$ENV{LIB} now used to search for libs under Visual C.
+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 *
-A failed (pseudo)fork now returns undef and sets errno to EAGAIN.
+C<Digest>, frontend module for calculating digests (checksums), from
+Gisle Aas, has been added. See L<Digest>.
=item *
-Allow REG_EXPAND_SZ keys in the registry.
+C<Digest::MD5> for calculating MD5 digests (checksums) as defined in
+RFC 1321, from Gisle Aas, has been added. See L<Digest::MD5>.
-=item *
+ use Digest::MD5 'md5_hex';
-Can now send() from all threads, not just the first one.
+ $digest = md5_hex("Thirsty Camel");
-=item *
+ print $digest, "\n"; # 01d19d9d2045e005c3f1b80e8b164de1
-Fake signal handling reenabled, bugs and all.
+NOTE: the C<MD5> backward compatibility module is deliberately not
+included since its further use is discouraged.
=item *
-Less stack reserved per thread so that more threads can run
-concurrently. (Still 16M per thread.)
+C<Encode>, by Nick Ing-Simmons, provides a mechanism to translate
+between different character encodings. Support for Unicode,
+ISO-8859-*, ASCII, CP*, KOI8-R, and three variants of EBCDIC are
+compiled in to the module. Several other encodings (like Japanese,
+Chinese, and MacIntosh encodings) are included and will be loaded at
+runtime. See L<Encode>.
+
+Any encoding supported by Encode module is also available to the
+":encoding()" layer if PerlIO is used.
=item *
-C<File::Spec->tmpdir()> now prefers C:/temp over /tmp
-(works better when perl is running as service).
+C<I18N::Langinfo> can be use to query locale information.
+See L<I18N::Langinfo>.
=item *
-Better UNC path handling under ithreads.
+C<I18N::LangTags> has functions for dealing with RFC3066-style
+language tags, by Sean Burke. See L<I18N::LangTags>.
=item *
-wait() and waitpid() now work much better.
+C<ExtUtils::Constant> is a new tool for extension writers for
+generating XS code to import C header constants, by Nicholas Clark.
+See L<ExtUtils::Constant>.
=item *
-winsock handle leak fixed.
+C<Filter::Simple> is an easy-to-use frontend to Filter::Util::Call,
+from Damian Conway. See L<Filter::Simple>.
-=back
+ # in MyFilter.pm:
-=back
+ package MyFilter;
-=head1 New or Changed Diagnostics
+ use Filter::Simple sub {
+ while (my ($from, $to) = splice @_, 0, 2) {
+ s/$from/$to/g;
+ }
+ };
-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.
+ 1;
-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>.
+ # in user's code:
-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.
+ use MyFilter qr/red/ => 'green';
-=head1 Changed Internals
+ print "red\n"; # this code is filtered, will print "green\n"
+ print "bored\n"; # this code is filtered, will print "bogreen\n"
-=over 4
+ no MyFilter;
+
+ print "red\n"; # this code is not filtered, will print "red\n"
=item *
-perlapi.pod (a companion to perlguts) now attempts to document the
-internal API.
+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 *
-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.
+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>.
=item *
-Added rsignal(), whichsig(), do_join() to the publicised API.
+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 *
-Made possible to propagate customised exceptions via croak()ing.
+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 *
-Added is_utf8_char(), is_utf8_string(), bytes_to_utf8(), and utf8_to_bytes().
+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.
-=item *
+ use Locale::Country;
-Now xsubs can have attributes just like subs.
+ $country = code2country('jp'); # $country gets 'Japan'
+ $code = country2code('Norway'); # $code gets 'no'
-=back
+See L<Locale::Constants>, L<Locale::Country>, L<Locale::Currency>,
+and L<Locale::Language>.
-=head1 Known Problems
+=item *
-=head2 Unicode Support Still Far From Perfect
+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.
-We're working on it. Stay tuned.
+=item *
-=head2 EBCDIC Still A Lost Platform
+C<Memoize> can make your functions faster by trading space for time,
+from Mark-Jason Dominus. See L<Memoize>.
-The plan is to bring them back.
+=item *
-=head2 Building Extensions Can Fail Because Of Largefiles
+C<MIME::Base64> allows you to encode data in base64, from Gisle Aas,
+as defined in RFC 2045 - I<MIME (Multipurpose Internet Mail
+Extensions)>.
-Certain extensions like mod_perl and BSD::Resource are known to have
-issues with `largefiles', a change brought by Perl 5.6.0 in which file
-offsets default to 64 bits wide, where supported. Modules may fail to
-compile at all or compile and work incorrectly. Currently there is no
-good solution for the problem, but Configure now provides appropriate
-non-largefile ccflags, ldflags, libswanted, and libs in the %Config
-hash (e.g., $Config{ccflags_nolargefiles}) so the extensions that are
-having problems can try configuring themselves without the
-largefileness. This is admittedly not a clean solution, and the
-solution may not even work at all. One potential failure is whether
-one can (or, if one can, whether it's a good idea) link together at
-all binaries with different ideas about file offsets, all this is
-platform-dependent.
+ use MIME::Base64;
-=head2 ftmp-security tests warn 'system possibly insecure'
+ $encoded = encode_base64('Aladdin:open sesame');
+ $decoded = decode_base64($encoded);
-Don't panic. Read INSTALL 'make test' section instead.
+ print $encoded, "\n"; # "QWxhZGRpbjpvcGVuIHNlc2FtZQ=="
-=head2 Test lib/posix Subtest 9 Fails In LP64-Configured HP-UX
+See L<MIME::Base64>.
-If perl is configured with -Duse64bitall, the successful result of the
-subtest 10 of lib/posix may arrive before the successful result of the
-subtest 9, which confuses the test harness so much that it thinks the
-subtest 9 failed.
+=item *
-=head2 Long Doubles Still Don't Work In Solaris
+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.
-The experimental long double support is still very much so in Solaris.
-(Other platforms like Linux and Tru64 are beginning to solidify in
-this area.)
+ use MIME::QuotedPrint;
-=head2 Linux With Sfio Fails op/misc Test 48
+ $encoded = encode_qp("Smiley in Unicode: \x{263a}");
+ $decoded = decode_qp($encoded);
-No known fix.
+ print $encoded, "\n"; # "Smiley in Unicode: =263A"
-=head2 Storable tests fail in some platforms
+MIME::QuotedPrint has been enhanced to provide the basic methods
+necessary to use it with PerlIO::Via as in :
-If any Storable tests fail the use of Storable is not advisable.
+ use MIME::QuotedPrint;
+ open($fh,">Via(MIME::QuotedPrint)",$path);
-=over 4
+See L<MIME::QuotedPrint>.
=item *
-Many Storable tests fail on AIX configured with 64 bit integers.
-
-So far unidentified problems break Storable in AIX if Perl is
-configured to use 64 bit integers. AIX in 32-bit mode works and
-other 64-bit platforms work with Storable.
+C<NEXT> is pseudo-class for method redispatch, from Damian Conway.
+See L<NEXT>.
=item *
-DOS DJGPP may hang when testing Storable.
+C<open> is a new pragma for setting the default I/O disciplines
+for open().
=item *
-st-06compat fails in UNICOS and UNICOS/mk.
-
-This means that you cannot read old (pre-Storable-0.7) Storable images
-made in other platforms.
+C<PerlIO::Scalar> provides the implementation of IO to "in memory"
+Perl scalars as discussed above, from Nick Ing-Simmons. It also
+serves as an example of a loadable PerlIO layer. Other future
+possibilities include PerlIO::Array and PerlIO::Code.
+See L<PerlIO::Scalar>.
=item *
-st-store.t and st-retrieve may fail with Compaq C 6.2 on OpenVMS Alpha 7.2.
-
-=back
+C<PerlIO::Via> acts as a PerlIO layer and wraps PerlIO layer
+functionality provided by a class (typically implemented in perl
+code), from Nick Ing-Simmons.
-=head2 Threads Are Still Experimental
+ use MIME::QuotedPrint;
+ open($fh,">Via(MIME::QuotedPrint)",$path);
-Multithreading is still an experimental feature. Some platforms
-emit the following message for lib/thr5005
+This will automatically convert everything output to C<$fh>
+to Quoted-Printable. See L<PerlIO::Via>.
- #
- # This is a KNOWN FAILURE, and one of the reasons why threading
- # is still an experimental feature. It is here to stop people
- # from deploying threads in production. ;-)
- #
+=item *
-and another known thread-related warning is
+C<Pod::ParseLink>, by Russ Allbery, has been added,
+to parse L<> links in pods as described in the new
+perlpodspec.
- pragma/overload......Unbalanced saves: 3 more saves than restores
- panic: magic_mutexfree during global destruction.
- ok
- lib/selfloader.......Unbalanced saves: 3 more saves than restores
- panic: magic_mutexfree during global destruction.
- ok
- lib/st-dclone........Unbalanced saves: 3 more saves than restores
- panic: magic_mutexfree during global destruction.
- ok
+=item *
-=head2 The Compiler Suite Is Still Experimental
+C<Pod::Text::Overstrike>, by Joe Smith, has been added.
+It converts POD data to formatted overstrike text.
+See L<Pod::Text::Overstrike>.
-The compiler suite is slowly getting better but is nowhere near
-working order yet. The backend part that has seen perhaps the most
-progress is the bytecode compiler.
+=item *
-=head1 Security Vulnerability Closed
+C<Scalar::Util> is a selection of general-utility scalar subroutines,
+like blessed(), reftype(), and tainted(). See L<Scalar::Util>.
-(This change was already made in 5.7.0 but bears repeating here.)
+=item *
-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 April 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.
+C<sort> is a new pragma for controlling the behaviour of sort().
-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.
+=item *
-The exploit attempt reporting feature has been completely removed from
-all the Perl 5.7 releases (and will be gone also from the maintenance
-release 5.6.1), 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/).
+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>.
-=head1 Incompatible Changes
+=item *
-=over 4
+C<Switch>, from Damian Conway, has been added. Just by saying
-=item *
+ use Switch;
-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">.
+you have C<switch> and C<case> available in Perl.
-=item *
+ use Switch;
-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.)
+ switch ($val) {
-=back
+ case 1 { print "number 1" }
+ case "a" { print "string a" }
+ case [1..10,42] { print "number in list" }
+ case (@array) { print "number in list" }
+ case /\w+/ { print "pattern" }
+ case qr/\w+/ { print "pattern" }
+ case (%hash) { print "entry in hash" }
+ case (\%hash) { print "entry in hash" }
+ case (\&sub) { print "arg to subroutine" }
+ else { print "previous case not true" }
+ }
-=head1 Core Enhancements
+See L<Switch>.
-=head2 AUTOLOAD Is Now Lvaluable
+=item *
-AUTOLOAD is now lvaluable, meaning that you can add the :lvalue attribute
-to AUTOLOAD subroutines and you can assign to the AUTOLOAD return value.
+C<Test::More> is yet another framework for writing test scripts,
+more extensive than Test::Simple, by Michael Schwern. See L<Test::More>.
-=head2 PerlIO is Now The Default
+=item *
-=over 4
+C<Test::Simple> has basic utilities for writing tests, by Michael
+Schwern. See L<Test::Simple>.
=item *
-IO is now by default done via PerlIO rather than system's "stdio".
-PerlIO allows "layers" to be "pushed" onto a file handle to alter the
-handle's behaviour. Layers can be specified at open time via 3-arg
-form of open:
+C<Text::Balanced> has been added, for extracting delimited text
+sequences from strings, from Damian Conway.
- open($fh,'>:crlf :utf8', $path) || ...
+ use Text::Balanced 'extract_delimited';
-or on already opened handles via extended C<binmode>:
+ ($a, $b) = extract_delimited("'never say never', he never said", "'", '');
- binmode($fh,':encoding(iso-8859-7)');
+$a will be "'never say never'", $b will be ', he never said'.
-The built-in layers are: unix (low level read/write), stdio (as in
-previous Perls), perlio (re-implementation of stdio buffering in a
-portable manner), crlf (does CRLF <=> "\n" translation as on Win32,
-but available on any platform). A mmap layer may be available if
-platform supports it (mostly UNIXes).
+In addition to extract_delimited() there are also extract_bracketed(),
+extract_quotelike(), extract_codeblock(), extract_variable(),
+extract_tagged(), extract_multiple(), gen_delimited_pat(), and
+gen_extract_tagged(). With these you can implement rather advanced
+parsing algorithms. See L<Text::Balanced>.
+
+=item *
-Layers to be applied by default may be specified via the 'open' pragma.
+C<threads> is an interface to interpreter threads, by Arthur Bergman.
+Interpreter threads (ithreads) is the new thread model introduced in
+Perl 5.6 but only available as an internal interface for extension
+writers (and for Win32 Perl for C<fork()> emulation). See L<threads>.
-See L</"Installation and Configuration Improvements"> for the effects
-of PerlIO on your architecture name.
+=item *
+
+C<threads::shared> allows data sharing for interpreter threads, from
+Arthur Bergman. In the ithreads model any data sharing between
+threads must be explicit, as opposed to the old 5.005 thread model
+where data sharing was implicit. See L<threads::shared>.
=item *
-File handles can be marked as accepting Perl's internal encoding of Unicode
-(UTF-8 or UTF-EBCDIC depending on platform) by a pseudo layer ":utf8" :
+C<Tie::RefHash::Nestable>, by Edward Avis, allows storing hash
+references (unlike the standard Tie::RefHash) The module is contained
+within Tie::RefHash, see L<Tie::RefHash>.
- open($fh,">:utf8","Uni.txt");
+=item *
-Note for EBCDIC users: the pseudo layer ":utf8" is erroneously named
-for you since it's not UTF-8 what you will be getting but instead
-UTF-EBCDIC. See L<perlunicode>, L<utf8>, and
-http://www.unicode.org/unicode/reports/tr16/ for more information.
-In future releases this naming may change.
+C<Time::HiRes> provides high resolution timing (ualarm, usleep,
+and gettimeofday), from Douglas E. Wegscheid. See L<Time::HiRes>.
=item *
-File handles can translate character encodings from/to Perl's internal
-Unicode form on read/write via the ":encoding()" layer.
+C<Unicode::UCD> offers a querying interface to the Unicode Character
+Database. See L<Unicode::UCD>.
=item *
-File handles can be opened to "in memory" files held in Perl scalars via:
+C<Unicode::Collate> implements the UCA (Unicode Collation Algorithm)
+for sorting Unicode strings, by SADAHIRO Tomoyuki. See L<Unicode::Collate>.
- open($fh,'>', \$variable) || ...
+=item *
+
+C<Unicode::Normalize> implements the various Unicode normalization
+forms, by SADAHIRO Tomoyuki. See L<Unicode::Normalize>.
=item *
-Anonymous temporary files are available without need to
-'use FileHandle' or other module via
+C<XS::Typemap>, by Tim Jenness, is a test extension that exercises XS
+typemaps. Nothing gets installed but for extension writers the code
+is worth studying.
- open($fh,"+>", undef) || ...
+=back
-That is a literal undef, not an undefined value.
+=head2 Updated And Improved Modules and Pragmata
+
+=over 4
=item *
-The list form of C<open> is now implemented for pipes (at least on UNIX):
+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.
- open($fh,"-|", 'cat', '/etc/motd')
+=item *
-creates a pipe, and runs the equivalent of exec('cat', '/etc/motd') in
-the child process.
+The attributes::reftype() now works on tied arguments.
=item *
-The following builtin functions are now overridable: chop(), chomp(),
-each(), keys(), pop(), push(), shift(), splice(), unshift().
+AutoLoader can now be disabled with C<no AutoLoader;>.
=item *
-Formats now support zero-padded decimal fields.
+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 *
-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.)
+Class::Struct can now define the classes in compile time.
=item *
-The printf() and sprintf() now support parameter reordering using the
-C<%\d+\$> and C<*\d+\$> syntaxes. For example
+Class::Struct now assigns the array/hash element if the accessor
+is called with an array/hash element as the B<sole> argument.
- print "%2\$s %1\$s\n", "foo", "bar";
+=item *
-will print "bar foo\n"; This feature helps in writing
-internationalised software.
+Data::Dumper has now an option to sort hashes.
=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)
+Data::Dumper has now an option to dump code references
+using B::Deparse.
=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
-considerations, is the Unihan database.
+DB_File now supports newer Berkeley DB versions, among
+other improvements.
=item *
-The Unicode character classes \p{Blank} and \p{SpacePerl} have been
-added. "Blank" is like C isblank(), that is, it contains only
-"horizontal whitespace" (the space character is, the newline isn't),
-and the "SpacePerl" is the Unicode equivalent of C<\s> (\p{Space}
-isn't, since that includes the vertical tabulator character, whereas
-C<\s> doesn't.)
+The English module can now be used without the infamous performance
+hit by saying
-=back
+ use English '-no_performance_hit';
-=head2 Signals Are Now Safe
+(Assuming, of course, that one doesn't need the troublesome variables
+C<$`>, C<$&>, or C<$'>.) Also, introduced C<@LAST_MATCH_START> and
+C<@LAST_MATCH_END> English aliases for C<@-> and C<@+>.
-Perl used to be fragile in that signals arriving at inopportune moments
-could corrupt Perl's internal state.
+=item *
-=head1 Modules and Pragmata
+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.
-=head2 New Modules
+=item *
-=over 4
+File::Find now chdir()s correctly when chasing symbolic links.
=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.
+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 *
-See L<B::Concise> for more information.
+File::Find is now (again) reentrant. It also has been made
+more portable.
=item *
-Class::ISA, by Sean Burke, for reporting the search path for a
-class's ISA tree, has been added.
+File::Glob::glob() renamed to File::Glob::bsd_glob() to avoid
+prototype mismatch with CORE::glob().
+
+=item *
-See L<Class::ISA> for more information.
+File::Glob now supports C<GLOB_LIMIT> constant to limit the size of
+the returned list of filenames.
=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.
+Devel::Peek now has an interface for the Perl memory statistics
+(this works only if you are using perl's malloc, and if you have
+compiled with debugging).
=item *
-Digest, a frontend module for calculating digests (checksums),
-from Gisle Aas, has been added.
+IPC::Open3 now allows the use of numeric file descriptors.
+
+=item *
-See L<Digest> for more information.
+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 *
-Digest::MD5 for calculating MD5 digests (checksums), by Gisle Aas,
-has been added.
+IO::Socket::INET has support for ReusePort option (if your platform
+supports it). The Reuse option now has an alias, ReuseAddr. For clarity
+you may want to prefer ReuseAddr.
- use Digest::MD5 'md5_hex';
+=item *
- $digest = md5_hex("Thirsty Camel");
+IO::Socket::INET now supports C<LocalPort> of zero (usually meaning
+that the operating system will make one up.)
- print $digest, "\n"; # 01d19d9d2045e005c3f1b80e8b164de1
+=item *
+
+use lib now works identically to @INC. Removing directories
+with 'no lib' now works.
-NOTE: the MD5 backward compatibility module is deliberately not
-included since its use is discouraged.
+=item *
-See L<Digest::MD5> for more information.
+Math::BigFloat and Math::BigInt have undergone a full rewrite.
+They are now magnitudes faster, and they support various
+bignum libraries such as GMP and PARI as their backends.
=item *
-Encode, by Nick Ing-Simmons, provides a mechanism to translate
-between different character encodings. Support for Unicode,
-ISO-8859-*, ASCII, CP*, KOI8-R, and three variants of EBCDIC are
-compiled in to the module. Several other encodings (like Japanese,
-Chinese, and MacIntosh encodings) are included and will be loaded at
-runtime.
+Math::Complex handles inf, NaN etc., better.
-Any encoding supported by Encode module is also available to the
-":encoding()" layer if PerlIO is used.
+=item *
-See L<Encode> for more information.
+Net::Ping has been enhanced. There is now "external" protocol which
+uses Net::Ping::External module which runs external ping(1) and parses
+the output. A version of Net::Ping::External is available in CPAN.
=item *
-Filter::Simple is an easy-to-use frontend to Filter::Util::Call,
-from Damian Conway.
+POSIX::sigaction() is now much more flexible and robust.
+You can now install coderef handlers, 'DEFAULT', and 'IGNORE'
+handlers, installing new handlers was not atomic.
- # in MyFilter.pm:
+=item *
- package MyFilter;
+In Safe the C<%INC> now localised in a Safe compartment so that
+use/require work.
- use Filter::Simple sub {
- while (my ($from, $to) = splice @_, 0, 2) {
- s/$from/$to/g;
- }
- };
+=item *
- 1;
+In SDBM_File on dosish platforms, some keys went missing because of
+lack of support for files with "holes". A workaround for the problem
+has been added.
- # in user's code:
+=item *
- use MyFilter qr/red/ => 'green';
+In Search::Dict one can now have a pre-processing hook for the
+lines being searched.
- print "red\n"; # this code is filtered, will print "green\n"
- print "bored\n"; # this code is filtered, will print "bogreen\n"
+=item *
- no MyFilter;
+The Shell module now has an OO interface.
- print "red\n"; # this code is not filtered, will print "red\n"
+=item *
-See L<Filter::Simple> for more information.
+The Test module has been significantly enhanced.
=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.
+The vars pragma now supports declaring fully qualified variables.
+(Something that C<our()> does not and will not support.)
=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.
+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.
- use Locale::Country;
+=back
- $country = code2country('jp'); # $country gets 'Japan'
- $code = country2code('Norway'); # $code gets 'no'
+=head1 Utility Changes
-See L<Locale::Constants>, L<Locale::Country>, L<Locale::Currency>,
-and L<Locale::Language> for more information.
+=over 4
=item *
-MIME::Base64, by Gisle Aas, allows you to encode data in base64.
+Emacs perl mode (emacs/cperl-mode.el) has been updated to version
+4.31.
- use MIME::Base64;
+=item *
- $encoded = encode_base64('Aladdin:open sesame');
- $decoded = decode_base64($encoded);
+F<emacs/e2ctags.pl> is now much faster.
- print $encoded, "\n"; # "QWxhZGRpbjpvcGVuIHNlc2FtZQ=="
+=item *
-See L<MIME::Base64> for more information.
+C<h2ph> now supports C trigraphs.
=item *
-MIME::QuotedPrint, by Gisle Aas, allows you to encode data in
-quoted-printable encoding.
+C<h2xs> now produces a template README.
- use MIME::QuotedPrint;
+=item *
- $encoded = encode_qp("Smiley in Unicode: \x{263a}");
- $decoded = decode_qp($encoded);
+C<h2xs> now uses C<Devel::PPort> for better portability between
+different versions of Perl.
- print $encoded, "\n"; # "Smiley in Unicode: =263A"
+=item *
-MIME::QuotedPrint has been enhanced to provide the basic methods
-necessary to use it with PerlIO::Via as in :
+C<h2xs> uses the new L<ExtUtils::Constant> module which will affect
+newly created extensions that define constants. Since the new code is
+more correct (if you have two constants where the first one is a
+prefix of the second one, the first constant B<never> gets defined),
+less lossy (it uses integers for integer constant, as opposed to the
+old code that used floating point numbers even for integer constants),
+and slightly faster, you might want to consider regenerating your
+extension code (the new scheme makes regenerating easy).
+L<h2xs> now also supports C trigraphs.
- use MIME::QuotedPrint;
- open($fh,">Via(MIME::QuotedPrint)",$path)
+=item *
-See L<MIME::QuotedPrint> for more information.
+C<libnetcfg> has been added to configure the libnet.
=item *
-PerlIO::Scalar, by Nick Ing-Simmons, provides the implementation of
-IO to "in memory" Perl scalars as discussed above. It also serves as
-an example of a loadable layer. Other future possibilities include
-PerlIO::Array and PerlIO::Code. See L<PerlIO::Scalar> for more
-information.
+C<perlbug> is now much more robust. It also sends the bug report to
+perl.org, not perl.com.
=item *
-PerlIO::Via, by Nick Ing-Simmons, acts as a PerlIO layer and wraps
-PerlIO layer functionality provided by a class (typically implemented
-in perl code).
+C<perlcc> has been rewritten and its user interface (that is,
+command line) is much more like that of the UNIX C compiler, cc.
+(The perlbc tools has been removed. Use C<perlcc -B> instead.)
- use MIME::QuotedPrint;
- open($fh,">Via(MIME::QuotedPrint)",$path)
+=item *
-This will automatically convert everything output to C<$fh>
-to Quoted-Printable. See L<PerlIO::Via> for more information.
+C<perlivp> is a new Installation Verification Procedure utility
+for running any time after installing Perl.
=item *
-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.
+C<pod2html> now allows specifying a cache directory.
=item *
-Switch from Damian Conway has been added. Just by saying
+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.)
- use Switch;
+=item *
-you have C<switch> and C<case> available in Perl.
+C<xsubpp> now understands POD documentation embedded in the *.xs files.
- use Switch;
+=item *
- switch ($val) {
+C<xsubpp> now supports OUT keyword.
- case 1 { print "number 1" }
- case "a" { print "string a" }
- case [1..10,42] { print "number in list" }
- case (@array) { print "number in list" }
- case /\w+/ { print "pattern" }
- case qr/\w+/ { print "pattern" }
- case (%hash) { print "entry in hash" }
- case (\%hash) { print "entry in hash" }
- case (\&sub) { print "arg to subroutine" }
- else { print "previous case not true" }
- }
+=back
-See L<Switch> for more information.
+=head1 New Documentation
+
+=over 4
=item *
-Text::Balanced from Damian Conway has been added, for
-extracting delimited text sequences from strings.
+perl56delta details the changes between the 5.005 release and the
+5.6.0 release.
- use Text::Balanced 'extract_delimited';
+=item *
- ($a, $b) = extract_delimited("'never say never', he never said", "'", '');
+perlclib documents the internal replacements for standard C library
+functions. (Interesting only for extension writers and Perl core
+hackers.)
-$a will be "'never say never'", $b will be ', he never said'.
+=item *
-In addition to extract_delimited() there are also extract_bracketed(),
-extract_quotelike(), extract_codeblock(), extract_variable(),
-extract_tagged(), extract_multiple(), gen_delimited_pat(), and
-gen_extract_tagged(). With these you can implement rather advanced
-parsing algorithms. See L<Text::Balanced> for more information.
+perldebtut is a Perl debugging tutorial.
=item *
-Tie::RefHash::Nestable, by Edward Avis, allows storing hash references
-(unlike the standard Tie::RefHash) The module is contained within
-Tie::RefHash.
+perlebcdic contains considerations for running Perl on EBCDIC platforms.
=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.
-
-=back
+perlintro is a gentle introduction to Perl.
-=head2 Updated And Improved Modules and Pragmata
+=item *
-=over 4
+perliol documents the internals of PerlIO with layers.
=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.
+perlmodstyle is a style guide for writing modules.
=item *
-Class::Struct can now define the classes in compile time.
+perlnewmod tells about writing and submitting a new module.
=item *
-Math::BigFloat has undergone much fixing, and in addition the fmod()
-function now supports modulus operations.
+perlpacktut is a pack() tutorial.
+
+=item *
-(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/)
+perlpod has been rewritten to be clearer and to record the best
+practices gathered over the years.
=item *
-Devel::Peek now has an interface for the Perl memory statistics
-(this works only if you are using perl's malloc, and if you have
-compiled with debugging).
+perlpodspec is a more formal specification of the pod format,
+mainly of interest for writers of pod applications, not to
+people writing in pod.
=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.
+perlretut is a regular expression tutorial.
=item *
-IO::Socket::INET has support for ReusePort option (if your platform
-supports it). The Reuse option now has an alias, ReuseAddr. For clarity
-you may want to prefer ReuseAddr.
+perlrequick is a regular expressions quick-start guide.
+Yes, much quicker than perlretut.
=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.
+perltodo has been updated.
=item *
-The C<open> pragma allows layers other than ":raw" and ":crlf" when
-using PerlIO.
+perltootc has been renamed as perltooc (to not to conflict
+with perltoot in filesystems restricted to "8.3" names)
=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.
+perluniintro is an introduction to using Unicode in Perl
+(perlunicode is more of a reference)
=item *
-The Test module has been significantly enhanced. Its use is
-greatly recommended for module writers.
+perlutil explains the command line utilities packaged with the Perl
+distribution.
+
+=back
+
+The following platform-specific documents are available before
+the installation as README.I<platform>, and after the installation
+as perlI<platform>:
+
+ 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 *
-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.
+The documentation for the POSIX-BC platform is called "BS2000", to avoid
+confusion with the Perl POSIX module.
-=back
+=item *
-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.
+The documentation for the WinCE platform is called "CE", to avoid
+confusion with the perlwin32 documentation on 8.3-restricted filesystems.
+
+=back
=head1 Performance Enhancements
=item *
+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 *
+
Hashes now use Bob Jenkins "One-at-a-Time" hashing key algorithm
(http://burtleburtle.net/bob/hash/doobs.html). This algorithm is
reasonably fast while producing a much better spread of values than
=back
-=head1 Utility Changes
+=head1 Installation and Configuration Improvements
+
+=head2 Generic Improvements
=over 4
=item *
-h2xs now produces template README.
+INSTALL now explains how you can configure Perl to use 64-bit
+integers even on non-64-bit platforms.
=item *
-s2p has been completely rewritten in Perl. (It is in fact a full
-implementation of sed in Perl.)
+Policy.sh policy change: if you are reusing a Policy.sh file
+(see INSTALL) and you use Configure -Dprefix=/foo/bar and in the old
+Policy $prefix eq $siteprefix and $prefix eq $vendorprefix, all of
+them will now be changed to the new prefix, /foo/bar. (Previously
+only $prefix changed.) If you do not like this new behaviour,
+specify prefix, siteprefix, and vendorprefix explicitly.
=item *
-xsubpp now supports OUT keyword.
-
-=back
-
-=head1 New Documentation
-
-=head2 perlclib
-
-Internal replacements for standard C library functions.
-(Interesting only for extension writers and Perl core hackers.)
-
-=head2 perliol
-
-Internals of PerlIO with layers.
-
-=head2 README.aix
+A new optional location for Perl libraries, otherlibdirs, is available.
+It can be used for example for vendor add-ons without disturbing Perl's
+own library directories.
-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>.
+=item *
-=head2 README.bs2000
+In many platforms the vendor-supplied 'cc' is too stripped-down to
+build Perl (basically, 'cc' doesn't do ANSI C). If this seems
+to be the case and 'cc' does not seem to be the GNU C compiler
+'gcc', an automatic attempt is made to find and use 'gcc' instead.
-Documentation on compiling Perl on the POSIX-BC platform (an EBCDIC
-mainframe environment) has been added.
+=item *
-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>.
+gcc needs to closely track the operating system release to avoid
+build problems. If Configure finds that gcc was built for a different
+operating system release than is running, it now gives a clearly visible
+warning that there may be trouble ahead.
-=head2 README.macos
+=item *
-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>.
+If binary compatibility with the 5.005 release is not wanted, Configure
+no longer suggests including the 5.005 modules in @INC.
-=head2 README.mpeix
+=item *
-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>.
+Configure C<-S> can now run non-interactively.
-=head2 README.solaris
+=item *
-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>.
+Configure support for pdp11-style memory models has been removed due
+to obsolescence.
-=head2 README.vos
+=item *
-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>.
+configure.gnu now works with options with whitespace in them.
-=head2 Porting/repository.pod
+=item *
-Documentation on how to use the Perl source repository has been added.
+installperl now outputs everything to STDERR.
-=head1 Installation and Configuration Improvements
+=item *
-=over 4
+$Config{byteorder} is now computed dynamically (this is more robust
+with "fat binaries" where an executable image contains binaries for
+more than one binary platform.)
=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.
-
-=back
-
-=head2 New Or Improved Platforms
-
-For the list of platforms known to support Perl,
-see L<perlport/"Supported Platforms">.
-
-=over 4
+Building Berkeley DB3 for compatibility modes for DB, NDBM, and ODBM
+has been documented in INSTALL.
=item *
-AIX dynamic loading should be now better supported.
+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 *
-After a long pause, AmigaOS has been verified to be happy with Perl.
+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 *
-EBCDIC platforms (z/OS, also known as OS/390, POSIX-BC, and VM/ESA)
-have been regained. Many test suite tests still fail and the
-co-existence of Unicode and EBCDIC isn't quite settled, but the
-situation is much better than with Perl 5.6. See L<perlos390>,
-L<perlbs2000> (for POSIX-BC), and L<perlvmesa> for more information.
+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 ...
-Building perl with -Duseithreads or -Duse5005threads now works under
-HP-UX 10.20 (previously it only worked under 10.30 or later). You will
-need a thread library package installed. See README.hpux.
+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
-=item *
+ make all test
-MacOS Classic (MacPerl has of course been available since
-perl 5.004 but now the source code bases of standard Perl
-and MacPerl have been synchronised)
+and Perl will be built and tested, all in /tmp/perl/build/directory.
=item *
-NCR MP-RAS is now supported.
+For Perl developers several new make targets for profiling
+and debugging have been added, see L<perlhack>.
+
+=over 8
=item *
-NonStop-UX is now 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 *
-Amdahl UTS is now supported.
+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 *
-z/OS (formerly known as OS/390, formerly known as MVS OE) has now
-support for dynamic loading. This is not selected by default,
-however, you must specify -Dusedl in the arguments of Configure.
+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
-=head2 Generic Improvements
-
-=over 4
-
=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.
+Guidelines of how to construct minimal Perl installations have
+been added to INSTALL.
=item *
-Some new Configure symbols, useful for extension writers:
-
-=over 8
-
-=item d_cmsghdr
-
-For struct cmsghdr.
-
-=item d_fcntl_can_lock
-
-Whether fcntl() can be used for file locking.
-
-=item d_fsync
-
-=item d_getitimer
-
-=item d_getpagsz
-
-For getpagesize(), though you should prefer POSIX::sysconf(_SC_PAGE_SIZE))
-
-=item d_msghdr_s
-
-For struct msghdr.
-
-=item need_va_copy
-
-Whether one needs to use Perl_va_copy() to copy varargs.
-
-=item d_readv
-
-=item d_recvmsg
-
-=item d_sendmsg
-
-=item sig_size
-
-The number of elements in an array needed to hold all the available signals.
+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>).
-=item d_sockatmark
+But note that the Thread.pm interface is now shared by both
+thread models.
-=item d_strtoq
+=back
-=item d_u32align
+=head2 New Or Improved Platforms
-Whether one needs to access character data aligned by U32 sized pointers.
+For the list of platforms known to support Perl,
+see L<perlport/"Supported Platforms">.
-=item d_ualarm
+=over 4
-=item d_usleep
+=item *
-=back
+AIX dynamic loading should be now better supported.
=item *
-Removed Configure symbols: the PDP-11 memory model settings: huge,
-large, medium, models.
+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 *
-SOCKS support is now much more robust.
+After a long pause, AmigaOS has been verified to be happy with Perl.
=item *
-If your file system supports symbolic links you can build Perl outside
-of the source directory by
+AtheOS (http://www.atheos.cx/) is a new platform.
- 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
+DG/UX platform now supports the 5.005-style threads. See L<perldgux>.
- make all test
+=item *
-and Perl will be built and tested, all in /tmp/perl/build/directory.
+DYNIX/ptx platform (a.k.a. dynixptx) is supported at or near osvers 4.5.2.
-=back
+=item *
-=head1 Selected Bug Fixes
+EBCDIC platforms (z/OS, also known as OS/390, POSIX-BC, and VM/ESA)
+have been regained. Many test suite tests still fail and the
+co-existence of Unicode and EBCDIC isn't quite settled, but the
+situation is much better than with Perl 5.6. See L<perlos390>,
+L<perlbs2000> (for POSIX-BC), and L<perlvmesa> for more information.
-Numerous memory leaks and uninitialized memory accesses have been hunted down.
-Most importantly anonymous subs used to leak quite a bit.
+=item *
-=over 4
+Building perl with -Duseithreads or -Duse5005threads now works under
+HP-UX 10.20 (previously it only worked under 10.30 or later). You will
+need a thread library package installed. See README.hpux.
=item *
-chop(@list) in list context returned the characters chopped in
-reverse order. This has been reversed to be in the right order.
+MacOS Classic (MacPerl has of course been available since
+perl 5.004 but now the source code bases of standard Perl
+and MacPerl have been synchronised)
=item *
-The order of DESTROYs has been made more predictable.
+MacOS X (or Darwin) should now be able to build Perl even on HFS+
+filesystems. (The case-insensitivity confused the Perl build process.)
=item *
-mkdir() now ignores trailing slashes in the directory name,
-as mandated by POSIX.
+NCR MP-RAS is now supported.
=item *
-Attributes (like :shared) didn't work with our().
+NetWare from Novell is now supported. See L<perlnetware>.
=item *
-The PERL5OPT environment variable (for passing command line arguments
-to Perl) didn't work for more than a single group of options.
+NonStop-UX is now supported.
=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.
+NEC SUPER-UX is now supported.
=item *
-All but the first argument of the IO syswrite() method are now optional.
+Amdahl UTS UNIX mainframe platform is now supported.
=item *
-Tie::ARRAY SPLICE method was broken.
+WinCE is now supported. See L<perlce>.
=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.
+z/OS (formerly known as OS/390, formerly known as MVS OE) has now
+support for dynamic loading. This is not selected by default,
+however, you must specify -Dusedl in the arguments of Configure.
=back
-=head2 Platform Specific Changes and Fixes
+=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 *
-Linux previously had problems related to sockaddrlen when using
-accept(), revcfrom() (in Perl: recv()), getpeername(), and getsockname().
+The autouse pragma didn't work for Multi::Part::Function::Names.
=item *
-Previously DYNIX/ptx had problems in its Configure probe for non-blocking I/O.
+caller() could cause core dumps in certain situations. Carp was sometimes
+affected by this problem.
=item *
-Windows
-
-=over 8
+chop(@list) in list context returned the characters chopped in
+reverse order. This has been reversed to be in the right order.
=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++).
+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 *
-Win32::GetCwd() correctly returns C:\ instead of C: when at the drive root.
-Other bugs in chdir() and Cwd::cwd() have also been fixed.
+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 *
-Duping socket handles with open(F, ">&MYSOCK") now works under Windows 9x.
+The order of DESTROYs has been made more predictable.
=item *
-HTML files will be installed in c:\perl\html instead of c:\perl\lib\pod\html
+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 makefiles now provide a single switch to bulk-enable all the features
-enabled in ActiveState ActivePerl (a popular binary distribution).
-
-=back
-
-=back
-
-=head1 New or Changed Diagnostics
-
-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.
+Perl 5.6.0 could emit spurious warnings about redefinition of dl_error()
+when statically building extensions into perl. This has been corrected.
-=over 4
+=item *
+
+L<dprofpp> -R didn't work.
=item *
-If an attempt to use a (non-blessed) reference as an array index
-is made, a warning is given.
+C<*foo{FORMAT}> now works.
+=item *
+
+Infinity is now recognized as a number.
=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.
+UNIVERSAL::isa no longer caches methods incorrectly. (This broke
+the Tk extension with 5.6.0.)
-=back
+=item *
-=head1 Changed Internals
+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.
-=over 4
+=item *
+
+Lexicals II: lexicals leaked at file scope into subroutines that
+were declared before the lexicals.
=item *
-Some new APIs: ptr_table_clear(), ptr_table_free(), sv_setref_uv().
-For the full list of the available APIs see L<perlapi>.
+Lexical warnings now propagating correctly between scopes
+and into C<eval "...">.
=item *
-dTHR and djSP have been obsoleted; the former removed (because it's
-a no-op) and the latter replaced with dSP.
+C<use warnings qw(FATAL all)> did not work as intended. This has been
+corrected.
=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).
+warnings::enabled() now reports the state of $^W correctly if the caller
+isn't using lexical warnings.
-=back
+=item *
-=head1 New Tests
+Line renumbering with eval and C<#line> now works.
-Many new tests have been added. The most notable is probably the
-lib/1_compile: it is very notable because running it takes quite a
-long time -- it test compiles all the Perl modules in the distribution.
-Please be patient.
+=item *
-=head1 Known Problems
+Fixed numerous memory leaks, especially in eval "".
-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.
+=item *
-=head2 AIX vac 5.0.0.0 May Produce Buggy Code For Perl
+mkdir() now ignores trailing slashes in the directory name,
+as mandated by POSIX.
-The AIX C compiler vac version 5.0.0.0 may produce buggy code,
-resulting in few random tests failing, but when the failing tests
-are run by hand, they succeed. We suggest upgrading to at least
-vac version 5.0.1.0, that has been known to compile Perl correctly.
-"lslpp -L|grep vac.C" will tell you the vac version.
+=item *
-=head2 lib/ftmp-security tests warn 'system possibly insecure'
+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.
-Don't panic. Read INSTALL 'make test' section instead.
+=item *
-=head2 lib/io_multihomed Fails In LP64-Configured HP-UX
+Modulus of unsigned numbers now works (4063328477 % 65535 used to
+return 27406, instead of 27047).
-The lib/io_multihomed test may hang in HP-UX if Perl has been
-configured to be 64-bit. Because other 64-bit platforms do not hang in
-this test, HP-UX is suspect. All other tests pass in 64-bit HP-UX. The
-test attempts to create and connect to "multihomed" sockets (sockets
-which have multiple IP addresses).
+=item *
-=head2 Test lib/posix Subtest 9 Fails In LP64-Configured HP-UX
+Some "not a number" warnings introduced in 5.6.0 eliminated to be
+more compatible with 5.005. Infinity is now recognised as a number.
-If perl is configured with -Duse64bitall, the successful result of the
-subtest 10 of lib/posix may arrive before the successful result of the
-subtest 9, which confuses the test harness so much that it thinks the
-subtest 9 failed.
+=item *
-=head2 lib/b test 19
+Numeric conversions did not recognize changes in the string value
+properly in certain circumstances.
-The test fails on various platforms (PA64 and IA64 are known), but the
-exact cause is still being investigated.
+=item *
-=head2 Linux With Sfio Fails op/misc Test 48
+Attributes (like :shared) didn't work with our().
-No known fix.
+=item *
-=head2 sigaction test 13 in VMS
+our() variables will not cause "will not stay shared" warnings.
-The test is known to fail; whether it's because of VMS of because
-of faulty test is not known.
+=item *
-=head2 sprintf tests 129 and 130
+"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.
-The op/sprintf tests 129 and 130 are known to fail on some platforms.
-Examples include any platform using sfio, and Compaq/Tandem's NonStop-UX.
-The failing platforms do not comply with the ANSI C Standard, line
-19ff on page 134 of ANSI X3.159 1989 to be exact. (They produce
-something else than "1" and "-1" when formatting 0.6 and -0.6 using
-the printf format "%.0f", most often they produce "0" and "-0".)
+=item *
-=head2 Failure of Thread tests
+pack "Z" now correctly terminates the string with "\0".
-The subtests 19 and 20 of lib/thr5005.t test 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. (Note that support for 5.005-style threading remains
-experimental.)
+=item *
-=head2 Localising a Tied Variable Leaks Memory
+Fix password routines which in some shadow password platforms
+(e.g. HP-UX) caused getpwent() to return every other entry.
- use Tie::Hash;
- tie my %tie_hash => 'Tie::StdHash';
+=item *
- ...
+The PERL5OPT environment variable (for passing command line arguments
+to Perl) didn't work for more than a single group of options.
- local($tie_hash{Foo}) = 1; # leaks
+=item *
-Code like the above is known to leak memory every time the local()
-is executed.
+PERL5OPT with embedded spaces didn't work.
-=head2 Self-tying of Arrays and Hashes Is Forbidden
+=item *
-Self-tying of arrays and hashes is broken in rather deep and
-hard-to-fix ways. As a stop-gap measure to avoid people from getting
-frustrated at the mysterious results (core dumps, most often) it is
-for now forbidden (you will get a fatal error even from an attempt).
+printf() no longer resets the numeric locale to "C".
-=head2 Building Extensions Can Fail Because Of Largefiles
+=item *
-Some extensions like mod_perl are known to have issues with
-`largefiles', a change brought by Perl 5.6.0 in which file offsets
-default to 64 bits wide, where supported. Modules may fail to compile
-at all or compile and work incorrectly. Currently there is no good
-solution for the problem, but Configure now provides appropriate
-non-largefile ccflags, ldflags, libswanted, and libs in the %Config
-hash (e.g., $Config{ccflags_nolargefiles}) so the extensions that are
-having problems can try configuring themselves without the
-largefileness. This is admittedly not a clean solution, and the
-solution may not even work at all. One potential failure is whether
-one can (or, if one can, whether it's a good idea) link together at
-all binaries with different ideas about file offsets, all this is
-platform-dependent.
+C<qw(a\\b)> now parses correctly as C<'a\\b'>.
-=head2 The Compiler Suite Is Still Experimental
+=item *
-The compiler suite is slowly getting better but is nowhere near
-working order yet.
+pos() did not return the correct value within s///ge in earlier
+versions. This is now handled correctly.
-=head1 Security Vulnerability Closed
+=item *
-(This change was already made in 5.7.0 but bears repeating here.)
+Printing quads (64-bit integers) with printf/sprintf now works
+without the q L ll prefixes (assuming you are on a quad-capable platform).
-A security vulnerability affecting all Perl versions prior to 5.6.1
-was found in August 2000. The vulnerability does not affect default
-installations and as far as is known affects only the Linux platform.
+=item *
-You should upgrade your Perl to 5.6.1 as soon as possible. Patches
-for earlier releases exist but using the patches require full
-recompilation from the source code anyway, so 5.6.1 is your best
-choice.
+Regular expressions on references and overloaded scalars now work.
-See http://www.cpan.org/src/5.0/sperl-2000-08-05/sperl-2000-08-05.txt
-for more information.
+=item *
-=head1 Incompatible Changes
+Right-hand side magic (GMAGIC) could in many cases such as string
+concatenation be invoked too many times.
-=head2 64-bit platforms and malloc
+=item *
-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.
+scalar() now forces scalar context even when used in void context.
-=head2 AIX Dynaloading
+=item *
-The AIX dynaloading now uses in AIX releases 4.3 and newer the native
-dlopen interface of AIX instead of the old emulated interface. This
-change will probably break backward compatibility with compiled
-modules. The change was made to make Perl more compliant with other
-applications like modperl which are using the AIX native interface.
+SOCKS support is now much more robust.
-=head2 Socket Extension Dynamic in VMS
+=item *
-The Socket extension is now dynamically loaded instead of being
-statically built in. This may or may not be a problem with ancient
-TCP/IP stacks of VMS: we do not know since we weren't able to test
-Perl in such configurations.
+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.
-=head2 Different Definition of the Unicode Character Classes \p{In...}
+=item *
-As suggested by the Unicode consortium, the Unicode character classes
-now prefer I<scripts> as opposed to I<blocks> (as defined by Unicode);
-in Perl, when the C<\p{In....}> and the C<\p{In....}> regular expression
-constructs are used. This has changed the definition of some of those
-character classes.
+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).
-The difference between scripts and blocks is that scripts are the
-glyphs used by a language or a group of languages, while the blocks
-are more artificial groupings of 256 characters based on the Unicode
-numbering.
+=item *
-In general this change results in more inclusive Unicode character
-classes, but changes to the other direction also do take place:
-for example while the script C<Latin> includes all the Latin
-characters and their various diacritic-adorned versions, it
-does not include the various punctuation or digits (since they
-are not solely C<Latin>).
+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.
-Changes in the character class semantics may have happened if a script
-and a block happen to have the same name, for example C<Hebrew>.
-In such cases the script wins and C<\p{InHebrew}> now means the script
-definition of Hebrew. The block definition in still available,
-though, by appending C<Block> to the name: C<\p{InHebrewBlock}> means
-what C<\p{InHebrew}> meant in perl 5.6.0. For the full list
-of affected character classes, see L<perlunicode/Blocks>.
+=item *
-=head2 Deprecations
+Some cases of inconsistent taint propagation (such as within hash
+values) have been fixed.
-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.
+=item *
-The syntaxes C<@a->[...]> and C<@h->{...}> have now been deprecated.
+The RE engine found in Perl 5.6.0 accidentally pessimised certain kinds
+of simple pattern matches. These are now handled better.
-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.
+=item *
-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.
+Regular expression debug output (whether through C<use re 'debug'>
+or via C<-Dr>) now looks better.
-The chdir(undef) and chdir('') behaviors to match chdir() has been
-deprecated. In future versions, chdir(undef) and chdir('') will
-simply fail.
+=item *
-=head1 Core Enhancements
+Multi-line matches like C<"a\nxb\n" =~ /(?!\A)x/m> were flawed. The
+bug has been fixed.
-In general a lot of fixing has happened in the area of Perl's
-understanding of numbers, both integer and floating point. Since in
-many systems the standard number parsing functions like C<strtoul()>
-and C<atof()> seem to have bugs, Perl tries to work around their
-deficiencies. This results hopefully in more accurate numbers.
+=item *
-=over 4
+Use of $& could trigger a core dump under some situations. This
+is now avoided.
=item *
-The rules for allowing underscores (underbars) in numeric constants
-have been relaxed and simplified: now you can have an underscore
-B<between digits>.
+The regular expression captured submatches ($1, $2, ...) are now
+more consistently unset if the match fails, instead of leaving false
+data lying around in them.
=item *
-GMAGIC (right-hand side magic) could in many cases such as string
-concatenation be invoked too many times.
+readline() on files opened in "slurp" mode could return an extra "" at
+the end in certain situations. This has been corrected.
=item *
-Lexicals I: lexicals outside an eval "" weren't resolved
-correctly inside a subroutine definition inside the eval "" if they
-were not already referenced in the top level of the eval""ed code.
+Autovivification of symbolic references of special variables described
+in L<perlvar> (as in C<${$num}>) was accidentally disabled. This works
+again now.
=item *
-Lexicals II: lexicals leaked at file scope into subroutines that
-were declared before the lexicals.
+Sys::Syslog ignored the C<LOG_AUTH> constant.
=item *
-Lvalue subroutines can now return C<undef> in list context.
+All but the first argument of the IO syswrite() method are now optional.
=item *
-The C<op_clear> and C<op_null> are now exported.
+$AUTOLOAD, sort(), lock(), and spawning subprocesses
+in multiple threads simultaneously are now thread-safe.
=item *
-A new special regular expression variable has been introduced:
-C<$^N>, which contains the most-recently closed group (submatch).
+Tie::ARRAY SPLICE method was broken.
=item *
-L<utime> now supports C<utime undef, undef, @files> to change the
-file timestamps to the current time.
+Allow read-only string on left hand side of non-modifying tr///.
=item *
-The Perl parser has been stress tested using both random input and
-Markov chain input.
+Several Unicode fixes.
+
+=over 8
=item *
-C<eval "v200"> now works.
+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.
=item *
-VMS now works under PerlIO.
+The character tables have been updated to Unicode 3.1.1.
=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>.
+Comparing with utf8 data does not magically upgrade non-utf8 data
+into utf8.
-=back
+=item *
-=head1 Modules and Pragmata
+C<IsAlnum>, C<IsAlpha>, and C<IsWord> now match titlecase.
-=head2 New Modules and Distributions
+=item *
-=over 4
+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 *
-L<Attribute::Handlers> - Simpler definition of attribute handlers
+The C<tr///> operator now works. Note that the C<tr///CU>
+functionality has been removed (but see pack('U0', ...)).
=item *
-L<ExtUtils::Constant> - generate XS code to import C header constants
+C<eval "v200"> now works.
=item *
-L<I18N::Langinfo> - query locale information
+Perl 5.6.0 parsed m/\x{ab}/ incorrectly, leading to spurious warnings.
+This has been corrected.
=item *
-L<I18N::LangTags> - functions for dealing with RFC3066-style language tags
+Zero entries were missing from the Unicode classes like C<IsDigit>.
+
+=back
=item *
-L<libnet> - a collection of perl5 modules related to network programming
+Large unsigned numbers (those above 2**31) could sometimes lose their
+unsignedness, causing bogus results in arithmetic operations.
-Perl installation leaves libnet unconfigured, use F<libnetcfg> to configure.
+=back
+
+=head2 Platform Specific Changes and Fixes
+
+=over 4
=item *
-L<List::Util> - selection of general-utility list subroutines
+BSDI 4.*
+
+Perl now works on post-4.0 BSD/OSes.
=item *
-L<Locale::Maketext> - framework for localization
+All BSDs
+
+Setting C<$0> now works (as much as possible; see L<perlvar> for details).
=item *
-L<Memoize> - Make your functions faster by trading space for time
+Cygwin
+
+Numerous updates; currently synchronised with Cygwin 1.1.4.
=item *
-L<NEXT> - pseudo-class for method redispatch
+Previously DYNIX/ptx had problems in its Configure probe for non-blocking I/O.
=item *
-L<Scalar::Util> - selection of general-utility scalar subroutines
+EPOC
+
+EPOC update after Perl 5.6.0. See README.epoc.
=item *
-L<Test::More> - yet another framework for writing test scripts
+FreeBSD 3.*
+
+Perl now works on post-3.0 FreeBSDs.
=item *
-L<Test::Simple> - Basic utilities for writing tests
+HP-UX
+
+README.hpux updated; C<Configure -Duse64bitall> now almost works.
=item *
-L<Time::HiRes> - high resolution ualarm, usleep, and gettimeofday
+IRIX
+
+Numerous compilation flag and hint enhancements; accidental mixing
+of 32-bit and 64-bit libraries (a doomed attempt) made much harder.
=item *
-L<Time::Piece> - Object Oriented time objects
+Linux
-(Previously known as L<Time::Object>.)
+=over 8
=item *
-L<Time::Seconds> - a simple API to convert seconds to other date values
+Long doubles should now work (see INSTALL).
=item *
-L<UnicodeCD> - Unicode Character Database
+Linux previously had problems related to sockaddrlen when using
+accept(), revcfrom() (in Perl: recv()), getpeername(), and getsockname().
=back
-=head2 Updated And Improved Modules and Pragmata
+=item *
-=over 4
+MacOS Classic
+
+Compilation of the standard Perl distribution in MacOS Classic should
+now work if you have the Metrowerks development environment and
+the missing Mac-specific toolkit bits. Contact the macperl mailing
+list for details.
=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.
+MPE/iX
+
+MPE/iX update after Perl 5.6.0. See README.mpeix.
=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.
+NetBSD/sparc
+
+Perl now works on NetBSD/sparc.
=item *
-L<Cwd> extension is now (even) faster.
+OS/2
+
+Now works with usethreads (see INSTALL).
=item *
-L<DB_File> extension has been updated to version 1.77.
+Solaris
+
+64-bitness using the Sun Workshop compiler now works.
=item *
-L<Fcntl>, L<Socket>, and L<Sys::Syslog> have been rewritten to use the
-new-style constant dispatch section (see L<ExtUtils::Constant>).
+Tru64 (aka Digital UNIX, aka DEC OSF/1)
+
+The operating system version letter now recorded in $Config{osvers}.
+Allow compiling with gcc (previously explicitly forbidden). Compiling
+with gcc still not recommended because buggy code results, even with
+gcc 2.95.2.
=item *
-L<File::Find> is now (again) reentrant. It also has been made
-more portable.
+Unicos
+
+Fixed various alignment problems that lead into core dumps either
+during build or later; no longer dies on math errors at runtime;
+now using full quad integers (64 bits), previously was using
+only 46 bit integers for speed.
=item *
-L<File::Glob> now supports C<GLOB_LIMIT> constant to limit the
-size of the returned list of filenames.
+VMS
-=item *
+chdir() now works better despite a CRT bug; now works with MULTIPLICITY
+(see INSTALL); now works with Perl's malloc.
-L<IO::Socket::INET> now supports C<LocalPort> of zero (usually meaning
-that the operating system will make one up.)
+The tainting of C<%ENV> elements via C<keys> or C<values> was previously
+unimplemented. It now works as documented.
-=item *
+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.
-The L<vars> pragma now supports declaring fully qualified variables.
-(Something that C<our()> does not and will not support.)
+POSIX-style signals are now emulated much better on VMS versions prior
+to 7.0.
-=back
+The C<system> function and backticks operator have improved
+functionality and better error handling.
-=head1 Utility Changes
+=item *
-=over 4
+Windows
+
+=over 8
=item *
-The F<emacs/e2ctags.pl> is now much faster.
+accept() no longer leaks memory.
=item *
-L<h2ph> now supports C trigraphs.
+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 *
-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.
+Better chdir() return value for a non-existent directory.
=item *
-L<libnetcfg> has been added to configure the libnet.
+Duping socket handles with open(F, ">&MYSOCK") now works under Windows 9x.
=item *
-The F<Pod::Html> (and thusly L<pod2html>) now allows specifying
-a cache directory.
+New %ENV entries now propagate to subprocesses.
-=back
+=item *
-=head1 New Documentation
+Current directory entries in %ENV are now correctly propagated to child
+processes.
-=over 4
+=item *
+
+$ENV{LIB} now used to search for libs under Visual C.
=item *
-L<Locale::Maketext::TPJ13> is an article about software localization,
-originally published in The Perl Journal #13, republished here with
-kind permission.
+fork() emulation has been improved in various ways, but still continues
+to be experimental. See L<perlfork> for known bugs and caveats.
=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>.
+A failed (pseudo)fork now returns undef and sets errno to EAGAIN.
=item *
-The F<Todo> and F<Todo-5.6> files have been merged into L<perltodo>.
+Win32::GetCwd() correctly returns C:\ instead of C: when at the drive root.
+Other bugs in chdir() and Cwd::cwd() have also been fixed.
=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.
+HTML files will be installed in c:\perl\html instead of c:\perl\lib\pod\html
-=back
+=item *
-=head1 Installation and Configuration Improvements
+The makefiles now provide a single switch to bulk-enable all the features
+enabled in ActiveState ActivePerl (a popular Win32 binary distribution).
-=head2 New Or Improved Platforms
+=item *
-=over 4
+Allow REG_EXPAND_SZ keys in the registry.
=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>.
+Can now send() from all threads, not just the first one.
=item *
-AtheOS (http://www.atheos.cx/) is a new platform.
+Fake signal handling reenabled, bugs and all.
=item *
-DG/UX platform now supports the 5.005-style threads. See L<perldgux>.
+%SIG has been enabled under USE_ITHREADS, but its use is completely
+unsupported under all configurations.
=item *
-DYNIX/ptx platform (a.k.a. dynixptx) is supported at or near osvers 4.5.2.
+Less stack reserved per thread so that more threads can run
+concurrently. (Still 16M per thread.)
=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>.
+C<File::Spec->tmpdir()> now prefers C:/temp over /tmp
+(works better when perl is running as service).
=item *
-MacOS X (or Darwin) should now be able to build Perl even on HFS+
-filesystems. (The case-insensitivity confused the Perl build process.)
+Better UNC path handling under ithreads.
=item *
-NetWare from Novell is now supported. See L<perlnetware>.
+wait(), waitpid() and backticks now return the correct exit status under
+Windows 9x.
=item *
-The Amdahl UTS UNIX mainframe platform is now supported.
+winsock handle leak fixed.
=back
-=head2 Generic Improvements
+=back
+
+=head1 New or Changed Diagnostics
=over 4
=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>.
+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 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.
+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 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>).
+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 *
-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>.
-
-=back
-
-=head1 Selected Bug Fixes
-
-=over 5
+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 *
-The autouse pragma didn't work for Multi::Part::Function::Names.
+If an attempt to use a (non-blessed) reference as an array index
+is made, a warning is given.
=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.
+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.
=item *
-L<dprofpp> -R didn't work.
+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.
=item *
-PERL5OPT with embedded spaces didn't work.
+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 *
-L<Sys::Syslog> ignored the C<LOG_AUTH> constant.
+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 *
-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.
-
-=back
+perlapi.pod (a companion to perlguts) now attempts to document the
+internal API.
-=head1 New or Changed Diagnostics
+=item *
-=over 4
+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 *
-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.
+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 *
-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.
+Made possible to propagate customised exceptions via croak()ing.
=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.
+Now xsubs can have attributes just like subs.
=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.
+dTHR and djSP have been obsoleted; the former removed (because it's
+a no-op) and the latter replaced with dSP.
-=back
+=item *
-=head1 Source Code Enhancements
+PERL_OBJECT has been completely removed.
-=head2 MAGIC constants
+=item *
The MAGIC constants (e.g. C<'P'>) have been macrofied
(e.g. C<PERL_MAGIC_TIED>) for better source code readability
and maintainability.
-=head2 Better commented code
-
-F<perly.c>, F<sv.c>, and F<sv.h> have now been extensively commented.
-
-=head2 Regex pre-/post-compilation items matched up
+=item *
The regex compiler now maintains a structure that identifies nodes in
the compiled bytecode with the corresponding syntactic features of the
C<offsets> member of the C<struct regexp>. See L<perldebguts> for more
complete information.
-=head2 gcc -Wall
+=item *
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.
+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 *
+
+F<perly.c>, F<sv.c>, and F<sv.h> have now been extensively commented.
+
+=item *
+
+Documentation on how to use the Perl source repository has been added
+to F<Porting/repository.pod>.
+
+=item *
+
+There are now several profiling make targets.
+
+=back
+
+=head1 Security Vulnerability Closed
+
+(This change was already made in 5.7.0 but bears repeating here.)
+
+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.
+
+The problem was caused by Perl trying to report a suspected security
+exploit attempt using an external program, /bin/mail. On Linux
+platforms the /bin/mail program had an undocumented feature which
+when combined with suidperl gave access to a root shell, resulting in
+a serious compromise instead of reporting the exploit attempt. If you
+don't have /bin/mail, or if you have 'safe setuid scripts', or if
+suidperl is not installed, you are safe.
+
+The exploit attempt reporting feature has been completely removed from
+Perl 5.8.0 (and the maintenance release 5.6.1, and it was removed also
+from all the Perl 5.7 releases), so that particular vulnerability
+isn't there anymore. However, further security vulnerabilities are,
+unfortunately, always possible. The suidperl functionality is most
+probably going to be removed in Perl 5.10. In any case, suidperl
+should only be used by security experts who know exactly what they are
+doing and why they are using suidperl instead of some other solution
+such as sudo (see http://www.courtesan.com/sudo/).
=head1 New Tests
-Several new tests have been added, especially for the F<lib> subsection.
+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.
+
+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 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
=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
This limitation will hopefully be fixed in future. (Subroutine
attributes work fine for tieing, see L<Attribute::Handlers>).
+One way to run into this limitation is to have a loop variable with
+attributes within a loop: the tie is called only once, not for each
+iteration of the loop.
+
=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