3 perldelta - what is new for perl v5.8.0
7 This document describes differences between the 5.6.0 release
10 Many of the bug fixes in 5.8.0 were already seen in the 5.6.1
11 maintenance release since the two releases were kept closely
14 If you are upgrading from Perl 5.005_03, you might also want
15 to read L<perl56delta>.
17 =head1 Highlights In 5.8.0
23 Better Unicode support
27 New Thread Implementation
35 Better Numeric Accuracy
43 More Extensive Regression Testing
47 =head1 Incompatible Changes
49 =head2 64-bit platforms and malloc
51 If your pointers are 64 bits wide, the Perl malloc is no longer being
52 used because it does not work well with 8-byte pointers. Also,
53 usually the system mallocs on such platforms are much better optimized
54 for such large memory models than the Perl malloc. Some memory-hungry
55 Perl applications like the PDL don't work well with Perl's malloc.
56 Finally, other applications than Perl (like modperl) tend to prefer
57 the system malloc. Such platforms include Alpha and 64-bit HPPA,
60 =head2 AIX Dynaloading
62 The AIX dynaloading now uses in AIX releases 4.3 and newer the native
63 dlopen interface of AIX instead of the old emulated interface. This
64 change will probably break backward compatibility with compiled
65 modules. The change was made to make Perl more compliant with other
66 applications like modperl which are using the AIX native interface.
68 =head2 Attributes for C<my> variables now handled at run-time.
70 The C<my EXPR : ATTRS> syntax now applies variable attributes at
71 run-time. (Subroutine and C<our> variables still get attributes applied
72 at compile-time.) See L<attributes> for additional details. In particular,
73 however, this allows variable attributes to be useful for C<tie> interfaces,
74 which was a deficiency of earlier releases. Note that the new semantics
75 doesn't work with the Attribute::Handlers module (as of version 0.76).
77 =head2 Socket Extension Dynamic in VMS
79 The Socket extension is now dynamically loaded instead of being
80 statically built in. This may or may not be a problem with ancient
81 TCP/IP stacks of VMS: we do not know since we weren't able to test
82 Perl in such configurations.
84 =head2 IEEE-format Floating Point Default on OpenVMS Alpha
86 Perl now uses IEEE format (T_FLOAT) as the default internal floating
87 point format on OpenVMS Alpha, potentially breaking binary compatibility
88 with external libraries or existing data. G_FLOAT is still available as
89 a configuration option. The default on VAX (D_FLOAT) has not changed.
91 =head2 New Unicode Properties
93 Unicode I<scripts> are now supported. Scripts are similar to (and superior
94 to) Unicode I<blocks>. The difference between scripts and blocks is that
95 scripts are the glyphs used by a language or a group of languages, while
96 the blocks are more artificial groupings of (mostly) 256 characters based
97 on the Unicode numbering.
99 In general, scripts are more inclusive, but not universally so. For
100 example, while the script C<Latin> includes all the Latin characters and
101 their various diacritic-adorned versions, it does not include the various
102 punctuation or digits (since they are not solely C<Latin>).
104 A number of other properties are now supported, including C<\p{L&}>,
105 C<\p{Any}> C<\p{Assigned}>, C<\p{Unassigned}>, C<\p{Blank}> and
106 C<\p{SpacePerl}> (along with their C<\P{...}> versions, of course).
107 See L<perlunicode> for details, and more additions.
109 The C<In> or C<Is> prefix to names used with the C<\p{...}> and C<\P{...}>
110 are now almost always optional. The only exception is that a C<In> prefix
111 is required to signify a Unicode block when a block name conflicts with a
112 script name. For example, C<\p{Tibetan}> refers to the script, while
113 C<\p{InTibetan}> refers to the block. When there is no name conflict, you
114 can omit the C<In> from the block name (e.g. C<\p{BraillePatterns}>), but
115 to be safe, it's probably best to always use the C<In>).
117 =head2 REF(...) Instead Of SCALAR(...)
119 A reference to a reference now stringifies as "REF(0x81485ec)" instead
120 of "SCALAR(0x81485ec)" in order to be more consistent with the return
123 =head2 pack/unpack D/F recycled
125 The undocumented pack/unpack template letters D/F have been recycled
126 for better use: now they stand for long double (if supported by the
127 platform) and NV (Perl internal floating point type). (They used
128 to be aliases for d/f, but you never knew that.)
136 The semantics of bless(REF, REF) were unclear and until someone proves
137 it to make some sense, it is forbidden.
141 The obsolete chat2 library that should never have been allowed
142 to escape the laboratory has been decommissioned.
146 The builtin dump() function has probably outlived most of its
147 usefulness. The core-dumping functionality will remain in future
148 available as an explicit call to C<CORE::dump()>, but in future
149 releases the behaviour of an unqualified C<dump()> call may change.
153 The very dusty examples in the eg/ directory have been removed.
154 Suggestions for new shiny examples welcome but the main issue is that
155 the examples need to be documented, tested and (most importantly)
160 The (bogus) escape sequences \8 and \9 now give an optional warning
161 ("Unrecognized escape passed through"). There is no need to \-escape
166 The list of filenames from glob() (or <...>) is now by default sorted
167 alphabetically to be csh-compliant (which is what happened before
168 in most UNIX platforms). (bsd_glob() does still sort platform
169 natively, ASCII or EBCDIC, unless GLOB_ALPHASORT is specified.)
173 Spurious syntax errors generated in certain situations, when glob()
174 caused File::Glob to be loaded for the first time, have been fixed.
178 Although "you shouldn't do that", it was possible to write code that
179 depends on Perl's hashed key order (Data::Dumper does this). The new
180 algorithm "One-at-a-Time" produces a different hashed key order.
181 More details are in L</"Performance Enhancements">.
185 lstat(FILEHANDLE) now gives a warning because the operation makes no sense.
186 In future releases this may become a fatal error.
190 The C<package;> syntax (C<package> without an argument) has been
191 deprecated. Its semantics were never that clear and its
192 implementation even less so. If you have used that feature to
193 disallow all but fully qualified variables, C<use strict;> instead.
197 The unimplemented POSIX regex features [[.cc.]] and [[=c=]] are still
198 recognised but now cause fatal errors. The previous behaviour of
199 ignoring them by default and warning if requested was unacceptable
200 since it, in a way, falsely promised that the features could be used.
204 The current user-visible implementation of pseudo-hashes (the weird
205 use of the first array element) is deprecated starting from Perl 5.8.0
206 and will be removed in Perl 5.10.0, and the feature will be
207 implemented differently. Not only is the current interface rather
208 ugly, but the current implementation slows down normal array and hash
209 use quite noticeably. The C<fields> pragma interface will remain
214 The syntaxes C<< @a->[...] >> and C<< %h->{...} >> have now been deprecated.
218 After years of trying the suidperl is considered to be too complex to
219 ever be considered truly secure. The suidperl functionality is likely
220 to be removed in a future release.
224 The long deprecated uppercase aliases for the string comparison
225 operators (EQ, NE, LT, LE, GE, GT) have now been removed.
229 The tr///C and tr///U features have been removed and will not return;
230 the interface was a mistake. Sorry about that. For similar
231 functionality, see pack('U0', ...) and pack('C0', ...).
235 Earlier Perls treated "sub foo (@bar)" as equivalent to "sub foo (@)".
236 The prototypes are now checked at compile-time for invalid characters.
237 An optional warning is generated ("Illegal character in prototype...")
238 but this may be upgraded to a fatal error in a future release.
242 =head1 Core Enhancements
244 =head2 PerlIO is Now The Default
250 IO is now by default done via PerlIO rather than system's "stdio".
251 PerlIO allows "layers" to be "pushed" onto a file handle to alter the
252 handle's behaviour. Layers can be specified at open time via 3-arg
255 open($fh,'>:crlf :utf8', $path) || ...
257 or on already opened handles via extended C<binmode>:
259 binmode($fh,':encoding(iso-8859-7)');
261 The built-in layers are: unix (low level read/write), stdio (as in
262 previous Perls), perlio (re-implementation of stdio buffering in a
263 portable manner), crlf (does CRLF <=> "\n" translation as on Win32,
264 but available on any platform). A mmap layer may be available if
265 platform supports it (mostly UNIXes).
267 Layers to be applied by default may be specified via the 'open' pragma.
269 See L</"Installation and Configuration Improvements"> for the effects
270 of PerlIO on your architecture name.
274 File handles can be marked as accepting Perl's internal encoding of Unicode
275 (UTF-8 or UTF-EBCDIC depending on platform) by a pseudo layer ":utf8" :
277 open($fh,">:utf8","Uni.txt");
279 Note for EBCDIC users: the pseudo layer ":utf8" is erroneously named
280 for you since it's not UTF-8 what you will be getting but instead
281 UTF-EBCDIC. See L<perlunicode>, L<utf8>, and
282 http://www.unicode.org/unicode/reports/tr16/ for more information.
283 In future releases this naming may change.
287 File handles can translate character encodings from/to Perl's internal
288 Unicode form on read/write via the ":encoding()" layer.
292 File handles can be opened to "in memory" files held in Perl scalars via:
294 open($fh,'>', \$variable) || ...
298 Anonymous temporary files are available without need to
299 'use FileHandle' or other module via
301 open($fh,"+>", undef) || ...
303 That is a literal undef, not an undefined value.
307 The list form of C<open> is now implemented for pipes (at least on UNIX):
309 open($fh,"-|", 'cat', '/etc/motd')
311 creates a pipe, and runs the equivalent of exec('cat', '/etc/motd') in
318 Perl used to be fragile in that signals arriving at inopportune moments
319 could corrupt Perl's internal state. Now Perl postpones handling of
320 signals until it's safe (between opcodes).
322 This change may have surprising side effects because signals no longer
323 interrupt Perl instantly. Perl will now first finish whatever it was
324 doing, like finishing an internal operation (like sort()) or an
325 external operation (like an I/O operation), and only then look at any
326 arrived signals (and before starting the next operation). No more corrupt
327 internal state since the current operation is always finished first,
328 but the signal may take more time to get heard. Note that breaking
329 out from potentially blocking operations should still work, though.
331 =head2 Unicode Overhaul
333 Unicode in general should be now much more usable than in Perl 5.6.0
334 (or even in 5.6.1). Unicode can be used in hash keys, Unicode in
335 regular expressions should work now, Unicode in tr/// should work now,
336 Unicode in I/O should work now.
342 The Unicode Character Database coming with Perl has been upgraded
343 to Unicode 3.1.1. For more information, see http://www.unicode.org/.
347 For developers interested in enhancing Perl's Unicode capabilities:
348 almost all the UCD files are included with the Perl distribution in
349 the F<lib/unicore subdirectory>. The most notable omission, for space
350 considerations, is the Unihan database.
354 The properties \p{Blank} and \p{SpacePerl} have been added. "Blank" is like
355 C isblank(), that is, it contains only "horizontal whitespace" (the space
356 character is, the newline isn't), and the "SpacePerl" is the Unicode
357 equivalent of C<\s> (\p{Space} isn't, since that includes the vertical
358 tabulator character, whereas C<\s> doesn't.)
360 See "New Unicode Properties" earlier in this document for additional
361 information on changes with Unicode properties.
365 =head2 Understanding of Numbers
367 In general a lot of fixing has happened in the area of Perl's
368 understanding of numbers, both integer and floating point. Since in
369 many systems the standard number parsing functions like C<strtoul()>
370 and C<atof()> seem to have bugs, Perl tries to work around their
371 deficiencies. This results hopefully in more accurate numbers.
373 Perl now tries internally to use integer values in numeric conversions
374 and basic arithmetics (+ - * /) if the arguments are integers, and
375 tries also to keep the results stored internally as integers.
376 This change leads to often slightly faster and always less lossy
377 arithmetics. (Previously Perl always preferred floating point numbers
380 =head2 Miscellaneous Changes
386 AUTOLOAD is now lvaluable, meaning that you can add the :lvalue attribute
387 to AUTOLOAD subroutines and you can assign to the AUTOLOAD return value.
391 C<perl -d:Module=arg,arg,arg> now works (previously one couldn't pass
392 in multiple arguments.)
396 The builtin dump() now gives an optional warning
397 C<dump() better written as CORE::dump()>,
398 meaning that by default C<dump(...)> is resolved as the builtin
399 dump() which dumps core and aborts, not as (possibly) user-defined
400 C<sub dump>. To call the latter, qualify the call as C<&dump(...)>.
401 (The whole dump() feature is to considered deprecated, and possibly
402 removed/changed in future releases.)
406 chomp() and chop() are now overridable. Note, however, that their
407 prototype (as given by C<prototype("CORE::chomp")> is undefined,
408 because it cannot be expressed and therefore one cannot really write
409 replacements to override these builtins.
413 END blocks are now run even if you exit/die in a BEGIN block.
414 Internally, the execution of END blocks is now controlled by
415 PL_exit_flags & PERL_EXIT_DESTRUCT_END. This enables the new
416 behaviour for Perl embedders. This will default in 5.10. See
421 Formats now support zero-padded decimal fields.
425 Lvalue subroutines can now return C<undef> in list context.
426 However, the lvalue subroutine feature still remains experimental.
430 A lost warning "Can't declare ... dereference in my" has been
431 restored (Perl had it earlier but it became lost in later releases.)
435 A new special regular expression variable has been introduced:
436 C<$^N>, which contains the most-recently closed group (submatch).
440 C<no Module;> now works even if there is no "sub unimport" in the Module.
444 The numerical comparison operators return C<undef> if either operand
445 is a NaN. Previously the behaviour was unspecified.
449 The following builtin functions are now overridable: each(), keys(),
450 pop(), push(), shift(), splice(), unshift().
454 C<pack() / unpack()> now can group template letters with C<()> and then
455 apply repetition/count modifiers on the groups.
459 C<pack() / unpack()> can now process the Perl internal numeric types:
460 IVs, UVs, NVs-- and also long doubles, if supported by the platform.
461 The template letters are C<j>, C<J>, C<F>, and C<D>.
465 C<pack('U0a*', ...)> can now be used to force a string to UTF8.
469 my __PACKAGE__ $obj now works.
473 The printf() and sprintf() now support parameter reordering using the
474 C<%\d+\$> and C<*\d+\$> syntaxes. For example
476 print "%2\$s %1\$s\n", "foo", "bar";
478 will print "bar foo\n". This feature helps in writing
479 internationalised software, and in general when the order
480 of the parameters can vary.
484 prototype(\&) is now available.
488 prototype(\[$@%&]) is now available to implicitly create references
489 (useful for example if you want to emulate the tie() interface).
493 A new command-line option, C<-t> is available. It is the
494 little brother of C<-T>: instead of dieing on taint violations,
495 lexical warnings are given. B<This is only meant as a temporary
496 debugging aid while securing the code of old legacy applications.
497 This is not a substitute for -T.>
501 In other taint news, the C<exec LIST> and C<system LIST> have now been
502 considered too risky (think C<exec @ARGV>: it can start any program
503 with any arguments), and now the said forms cause a warning.
504 You should carefully launder the arguments to guarantee their
505 validity. In future releases of Perl the forms will become fatal
506 errors so consider starting laundering now.
510 If tr/// is just counting characters, it doesn't attempt to
515 untie() will now call an UNTIE() hook if it exists. See L<perltie>
520 L<utime> now supports C<utime undef, undef, @files> to change the
521 file timestamps to the current time.
525 The rules for allowing underscores (underbars) in numeric constants
526 have been relaxed and simplified: now you can have an underscore
527 simply B<between digits>.
531 Rather than relying on C's argv[0] (which may not contain a full pathname)
532 where possible $^X is now set by asking the operating system.
533 (eg by reading F</proc/self/exe> on Linux, F</proc/curproc/file> on FreeBSD)
537 =head1 Modules and Pragmata
539 =head2 New Modules and Pragmata
545 C<Attribute::Handlers> allows a class to define attribute handlers.
548 use Attribute::Handlers;
549 sub Wolf :ATTR(SCALAR) { print "howl!\n" }
551 # later, in some package using or inheriting from MyPack...
553 my MyPack $Fluffy : Wolf; # the attribute handler Wolf will be called
555 Both variables and routines can have attribute handlers. Handlers can
556 be specific to type (SCALAR, ARRAY, HASH, or CODE), or specific to the
557 exact compilation phase (BEGIN, CHECK, INIT, or END).
561 B<B::Concise> is a new compiler backend for walking the Perl syntax
562 tree, printing concise info about ops, from Stephen McCamant. The
563 output is highly customisable. See L<B::Concise>.
567 C<Class::ISA> for reporting the search path for a class's ISA tree,
568 by Sean Burke, has been added. See L<Class::ISA>.
572 C<Cwd> has now a split personality: if possible, an XS extension is
573 used, (this will hopefully be faster, more secure, and more robust)
574 but if not possible, the familiar Perl implementation is used.
578 C<Devel::PPPort>, originally from Kenneth Albanowski and now
579 maintained by Paul Marquess, has been added. It is primarily used
580 by C<h2xs> to enhance portability of XS modules between different
585 C<Digest>, frontend module for calculating digests (checksums), from
586 Gisle Aas, has been added. See L<Digest>.
590 C<Digest::MD5> for calculating MD5 digests (checksums) as defined in
591 RFC 1321, from Gisle Aas, has been added. See L<Digest::MD5>.
593 use Digest::MD5 'md5_hex';
595 $digest = md5_hex("Thirsty Camel");
597 print $digest, "\n"; # 01d19d9d2045e005c3f1b80e8b164de1
599 NOTE: the C<MD5> backward compatibility module is deliberately not
600 included since its further use is discouraged.
604 C<Encode>, by Nick Ing-Simmons, provides a mechanism to translate
605 between different character encodings. Support for Unicode,
606 ISO-8859-*, ASCII, CP*, KOI8-R, and three variants of EBCDIC are
607 compiled in to the module. Several other encodings (like Japanese,
608 Chinese, and MacIntosh encodings) are included and will be loaded at
609 runtime. See L<Encode>.
611 Any encoding supported by Encode module is also available to the
612 ":encoding()" layer if PerlIO is used.
616 C<I18N::Langinfo> can be use to query locale information.
617 See L<I18N::Langinfo>.
621 C<I18N::LangTags> has functions for dealing with RFC3066-style
622 language tags, by Sean Burke. See L<I18N::LangTags>.
626 C<ExtUtils::Constant> is a new tool for extension writers for
627 generating XS code to import C header constants, by Nicholas Clark.
628 See L<ExtUtils::Constant>.
632 C<Filter::Simple> is an easy-to-use frontend to Filter::Util::Call,
633 from Damian Conway. See L<Filter::Simple>.
639 use Filter::Simple sub {
640 while (my ($from, $to) = splice @_, 0, 2) {
649 use MyFilter qr/red/ => 'green';
651 print "red\n"; # this code is filtered, will print "green\n"
652 print "bored\n"; # this code is filtered, will print "bogreen\n"
656 print "red\n"; # this code is not filtered, will print "red\n"
660 C<File::Temp> allows one to create temporary files and directories in
661 an easy, portable, and secure way, by Tim Jenness. See L<File::Temp>.
665 C<Filter::Util::Call> provides you with the framework to write
666 I<Source Filters> in Perl, from Paul Marquess. For most uses the
667 frontend Filter::Simple is to be preferred. See L<Filter::Util::Call>.
671 C<if> is a new pragma for conditional inclusion of modules, from
676 L<libnet> is a collection of perl5 modules related to network
677 programming, from Graham Barr. See L<Net::FTP>, L<Net::NNTP>,
678 L<Net::Ping>, L<Net::POP3>, L<Net::SMTP>, and L<Net::Time>.
680 Perl installation leaves libnet unconfigured, use F<libnetcfg> to configure.
684 C<List::Util> is a selection of general-utility list subroutines, like
685 sum(), min(), first(), and shuffle(), by Graham Barr. See L<List::Util>.
689 C<Locale::Constants>, C<Locale::Country>, C<Locale::Currency>, and
690 C<Locale::Language>, from Neil Bowers, have been added. They provide the
691 codes for various locale standards, such as "fr" for France, "usd" for
692 US Dollar, and "jp" for Japanese.
696 $country = code2country('jp'); # $country gets 'Japan'
697 $code = country2code('Norway'); # $code gets 'no'
699 See L<Locale::Constants>, L<Locale::Country>, L<Locale::Currency>,
700 and L<Locale::Language>.
704 C<Locale::Maketext> is localization framework from Sean Burke. See
705 L<Locale::Maketext>, and L<Locale::Maketext::TPJ13>. The latter is an
706 article about software localization, originally published in The Perl
707 Journal #13, republished here with kind permission.
711 C<Memoize> can make your functions faster by trading space for time,
712 from Mark-Jason Dominus. See L<Memoize>.
716 C<MIME::Base64> allows you to encode data in base64, from Gisle Aas,
717 as defined in RFC 2045 - I<MIME (Multipurpose Internet Mail
722 $encoded = encode_base64('Aladdin:open sesame');
723 $decoded = decode_base64($encoded);
725 print $encoded, "\n"; # "QWxhZGRpbjpvcGVuIHNlc2FtZQ=="
731 C<MIME::QuotedPrint> allows you to encode data in quoted-printable
732 encoding, as defined in RFC 2045 - I<MIME (Multipurpose Internet Mail
733 Extensions)>, from Gisle Aas.
735 use MIME::QuotedPrint;
737 $encoded = encode_qp("Smiley in Unicode: \x{263a}");
738 $decoded = decode_qp($encoded);
740 print $encoded, "\n"; # "Smiley in Unicode: =263A"
742 MIME::QuotedPrint has been enhanced to provide the basic methods
743 necessary to use it with PerlIO::Via as in :
745 use MIME::QuotedPrint;
746 open($fh,">Via(MIME::QuotedPrint)",$path);
748 See L<MIME::QuotedPrint>.
752 C<NEXT> is pseudo-class for method redispatch, from Damian Conway.
757 C<open> is a new pragma for setting the default I/O disciplines
762 C<PerlIO::Scalar> provides the implementation of IO to "in memory"
763 Perl scalars as discussed above, from Nick Ing-Simmons. It also
764 serves as an example of a loadable PerlIO layer. Other future
765 possibilities include PerlIO::Array and PerlIO::Code.
766 See L<PerlIO::Scalar>.
770 C<PerlIO::Via> acts as a PerlIO layer and wraps PerlIO layer
771 functionality provided by a class (typically implemented in perl
772 code), from Nick Ing-Simmons.
774 use MIME::QuotedPrint;
775 open($fh,">Via(MIME::QuotedPrint)",$path);
777 This will automatically convert everything output to C<$fh>
778 to Quoted-Printable. See L<PerlIO::Via>.
782 C<Pod::ParseLink>, by Russ Allbery, has been added,
783 to parse LZ<><> links in pods as described in the new
788 C<Pod::Text::Overstrike>, by Joe Smith, has been added.
789 It converts POD data to formatted overstrike text.
790 See L<Pod::Text::Overstrike>.
794 C<Scalar::Util> is a selection of general-utility scalar subroutines,
795 like blessed(), reftype(), and tainted(). See L<Scalar::Util>.
799 C<sort> is a new pragma for controlling the behaviour of sort().
803 C<Storable> gives persistence to Perl data structures by allowing the
804 storage and retrieval of Perl data to and from files in a fast and
805 compact binary format, from Raphael Manfredi. See L<Storable>.
809 C<Switch>, from Damian Conway, has been added. Just by saying
813 you have C<switch> and C<case> available in Perl.
819 case 1 { print "number 1" }
820 case "a" { print "string a" }
821 case [1..10,42] { print "number in list" }
822 case (@array) { print "number in list" }
823 case /\w+/ { print "pattern" }
824 case qr/\w+/ { print "pattern" }
825 case (%hash) { print "entry in hash" }
826 case (\%hash) { print "entry in hash" }
827 case (\&sub) { print "arg to subroutine" }
828 else { print "previous case not true" }
835 C<Test::More> is yet another framework for writing test scripts,
836 more extensive than Test::Simple, by Michael Schwern. See L<Test::More>.
840 C<Test::Simple> has basic utilities for writing tests, by Michael
841 Schwern. See L<Test::Simple>.
845 C<Text::Balanced> has been added, for extracting delimited text
846 sequences from strings, from Damian Conway.
848 use Text::Balanced 'extract_delimited';
850 ($a, $b) = extract_delimited("'never say never', he never said", "'", '');
852 $a will be "'never say never'", $b will be ', he never said'.
854 In addition to extract_delimited() there are also extract_bracketed(),
855 extract_quotelike(), extract_codeblock(), extract_variable(),
856 extract_tagged(), extract_multiple(), gen_delimited_pat(), and
857 gen_extract_tagged(). With these you can implement rather advanced
858 parsing algorithms. See L<Text::Balanced>.
862 C<threads> is an interface to interpreter threads, by Arthur Bergman.
863 Interpreter threads (ithreads) is the new thread model introduced in
864 Perl 5.6 but only available as an internal interface for extension
865 writers (and for Win32 Perl for C<fork()> emulation). See L<threads>.
869 C<threads::shared> allows data sharing for interpreter threads, from
870 Arthur Bergman. In the ithreads model any data sharing between
871 threads must be explicit, as opposed to the old 5.005 thread model
872 where data sharing was implicit. See L<threads::shared>.
876 C<Tie::File>, by Mark-Jason Dominus, associates a Perl array with the
881 C<Tie::Memoize>, by Ilya Zakharevich, provides on-demand loaded hashes.
885 C<Tie::RefHash::Nestable>, by Edward Avis, allows storing hash
886 references (unlike the standard Tie::RefHash) The module is contained
887 within Tie::RefHash, see L<Tie::RefHash>.
891 C<Time::HiRes> provides high resolution timing (ualarm, usleep,
892 and gettimeofday), from Douglas E. Wegscheid. See L<Time::HiRes>.
896 C<Unicode::UCD> offers a querying interface to the Unicode Character
897 Database. See L<Unicode::UCD>.
901 C<Unicode::Collate> implements the UCA (Unicode Collation Algorithm)
902 for sorting Unicode strings, by SADAHIRO Tomoyuki. See L<Unicode::Collate>.
906 C<Unicode::Normalize> implements the various Unicode normalization
907 forms, by SADAHIRO Tomoyuki. See L<Unicode::Normalize>.
911 C<XS::Typemap>, by Tim Jenness, is a test extension that exercises XS
912 typemaps. Nothing gets installed but for extension writers the code
917 =head2 Updated And Improved Modules and Pragmata
923 The following independently supported modules have been updated to the
924 newest versions from CPAN: CGI, CPAN, DB_File, File::Spec, File::Temp,
925 Getopt::Long, Math::BigFloat, Math::BigInt, the podlators bundle
926 (Pod::Man, Pod::Text), Pod::LaTeX, Pod::Parser, Storable,
927 Term::ANSIColor, Test, Text-Tabs+Wrap.
931 The attributes::reftype() now works on tied arguments.
935 AutoLoader can now be disabled with C<no AutoLoader;>.
939 B::Deparse has been significantly enhanced. It now can deparse almost
940 all of the standard test suite (so that the tests still succeed).
941 There is a make target "test.deparse" for trying this out.
945 Class::Struct can now define the classes in compile time.
949 Class::Struct now assigns the array/hash element if the accessor
950 is called with an array/hash element as the B<sole> argument.
954 Data::Dumper has now an option to sort hashes.
958 Data::Dumper has now an option to dump code references
963 DB_File now supports newer Berkeley DB versions, among
968 The English module can now be used without the infamous performance
971 use English '-no_match_vars';
973 (Assuming, of course, that one doesn't need the troublesome variables
974 C<$`>, C<$&>, or C<$'>.) Also, introduced C<@LAST_MATCH_START> and
975 C<@LAST_MATCH_END> English aliases for C<@-> and C<@+>.
979 Fcntl, Socket, and Sys::Syslog have been rewritten to use the
980 new-style constant dispatch section (see L<ExtUtils::Constant>).
981 This means that they will be more robust and hopefully faster.
985 File::Find now chdir()s correctly when chasing symbolic links.
989 File::Find now has pre- and post-processing callbacks. It also
990 correctly changes directories when chasing symbolic links. Callbacks
991 (naughtily) exiting with "next;" instead of "return;" now work.
995 File::Find is now (again) reentrant. It also has been made
1000 File::Glob::glob() renamed to File::Glob::bsd_glob() to avoid
1001 prototype mismatch with CORE::glob().
1005 File::Glob now supports C<GLOB_LIMIT> constant to limit the size of
1006 the returned list of filenames.
1010 Devel::Peek now has an interface for the Perl memory statistics
1011 (this works only if you are using perl's malloc, and if you have
1012 compiled with debugging).
1016 IPC::Open3 now allows the use of numeric file descriptors.
1020 IO::Socket has now atmark() method, which returns true if the socket
1021 is positioned at the out-of-band mark. The method is also exportable
1022 as a sockatmark() function.
1026 IO::Socket::INET has support for ReusePort option (if your platform
1027 supports it). The Reuse option now has an alias, ReuseAddr. For clarity
1028 you may want to prefer ReuseAddr.
1032 IO::Socket::INET now supports C<LocalPort> of zero (usually meaning
1033 that the operating system will make one up.)
1037 use lib now works identically to @INC. Removing directories
1038 with 'no lib' now works.
1042 ExtUtils::MakeMaker now uses File::Spec internally, which hopefully
1043 leads into better portability.
1047 Math::BigFloat and Math::BigInt have undergone a full rewrite.
1048 They are now magnitudes faster, and they support various
1049 bignum libraries such as GMP and PARI as their backends.
1053 Math::Complex handles inf, NaN etc., better.
1057 Net::Ping has been muchly enhanced. Multihoming is now supported.
1058 There is now "external" protocol which uses Net::Ping::External module
1059 which runs external ping(1) and parses the output. A version of
1060 Net::Ping::External is available in CPAN.
1064 POSIX::sigaction() is now much more flexible and robust.
1065 You can now install coderef handlers, 'DEFAULT', and 'IGNORE'
1066 handlers, installing new handlers was not atomic.
1070 In Safe the C<%INC> now localised in a Safe compartment so that
1075 In SDBM_File on dosish platforms, some keys went missing because of
1076 lack of support for files with "holes". A workaround for the problem
1081 In Search::Dict one can now have a pre-processing hook for the
1082 lines being searched.
1086 The Shell module now has an OO interface.
1090 The Test module has been significantly enhanced.
1094 The vars pragma now supports declaring fully qualified variables.
1095 (Something that C<our()> does not and will not support.)
1099 The C<utf8::> name space (as in the pragma) provides various
1100 Perl-callable functions to provide low level access to Perl's
1101 internal Unicode representation. At the moment only length()
1102 has been implemented.
1106 =head1 Utility Changes
1112 Emacs perl mode (emacs/cperl-mode.el) has been updated to version
1117 F<emacs/e2ctags.pl> is now much faster.
1121 C<h2ph> now supports C trigraphs.
1125 C<h2xs> now produces a template README.
1129 C<h2xs> now uses C<Devel::PPort> for better portability between
1130 different versions of Perl.
1134 C<h2xs> uses the new L<ExtUtils::Constant> module which will affect
1135 newly created extensions that define constants. Since the new code is
1136 more correct (if you have two constants where the first one is a
1137 prefix of the second one, the first constant B<never> gets defined),
1138 less lossy (it uses integers for integer constant, as opposed to the
1139 old code that used floating point numbers even for integer constants),
1140 and slightly faster, you might want to consider regenerating your
1141 extension code (the new scheme makes regenerating easy).
1142 L<h2xs> now also supports C trigraphs.
1146 C<libnetcfg> has been added to configure the libnet.
1150 C<perlbug> is now much more robust. It also sends the bug report to
1151 perl.org, not perl.com.
1155 C<perlcc> has been rewritten and its user interface (that is,
1156 command line) is much more like that of the UNIX C compiler, cc.
1157 (The perlbc tools has been removed. Use C<perlcc -B> instead.)
1161 C<perlivp> is a new Installation Verification Procedure utility
1162 for running any time after installing Perl.
1166 C<pod2html> now allows specifying a cache directory.
1170 C<s2p> has been completely rewritten in Perl. (It is in fact a full
1171 implementation of sed in Perl: you can use the sed functionality by
1172 using the C<psed> utility.)
1176 C<xsubpp> now understands POD documentation embedded in the *.xs files.
1180 C<xsubpp> now supports OUT keyword.
1184 =head1 New Documentation
1190 perl56delta details the changes between the 5.005 release and the
1195 perlclib documents the internal replacements for standard C library
1196 functions. (Interesting only for extension writers and Perl core
1201 perldebtut is a Perl debugging tutorial.
1205 perlebcdic contains considerations for running Perl on EBCDIC platforms.
1209 perlintro is a gentle introduction to Perl.
1213 perliol documents the internals of PerlIO with layers.
1217 perlmodstyle is a style guide for writing modules.
1221 perlnewmod tells about writing and submitting a new module.
1225 perlpacktut is a pack() tutorial.
1229 perlpod has been rewritten to be clearer and to record the best
1230 practices gathered over the years.
1234 perlpodspec is a more formal specification of the pod format,
1235 mainly of interest for writers of pod applications, not to
1236 people writing in pod.
1240 perlretut is a regular expression tutorial.
1244 perlrequick is a regular expressions quick-start guide.
1245 Yes, much quicker than perlretut.
1249 perltodo has been updated.
1253 perltootc has been renamed as perltooc (to not to conflict
1254 with perltoot in filesystems restricted to "8.3" names)
1258 perluniintro is an introduction to using Unicode in Perl.
1259 (perlunicode is more of a detailed reference and background
1264 perlutil explains the command line utilities packaged with the Perl
1269 The following platform-specific documents are available before
1270 the installation as README.I<platform>, and after the installation
1273 perlaix perlamiga perlapollo perlbeos perlbs2000
1274 perlce perlcygwin perldgux perldos perlepoc perlhpux
1275 perlhurd perlmachten perlmacos perlmint perlmpeix
1276 perlnetware perlos2 perlos390 perlplan9 perlqnx perlsolaris
1277 perltru64 perluts perlvmesa perlvms perlvos perlwin32
1283 The documentation for the POSIX-BC platform is called "BS2000", to avoid
1284 confusion with the Perl POSIX module.
1288 The documentation for the WinCE platform is called "CE", to avoid
1289 confusion with the perlwin32 documentation on 8.3-restricted filesystems.
1293 =head1 Performance Enhancements
1299 map() could get pathologically slow when the result list it generates
1300 is larger than the source list. The performance has been improved for
1305 sort() has been changed to use primarily mergesort internally as
1306 opposed to the earlier quicksort. For very small lists this may
1307 result in slightly slower sorting times, but in general the speedup
1308 should be at least 20%. Additional bonuses are that the worst case
1309 behaviour of sort() is now better (in computer science terms it now
1310 runs in time O(N log N), as opposed to quicksort's Theta(N**2)
1311 worst-case run time behaviour), and that sort() is now stable
1312 (meaning that elements with identical keys will stay ordered as they
1313 were before the sort). See the C<sort> pragma for information.
1315 The story in more detail: suppose you want to serve yourself a little
1318 @digits = ( 3,1,4,1,5,9 );
1320 A numerical sort of the digits will yield (1,1,3,4,5,9), as expected.
1321 Which C<1> comes first is hard to know, since one C<1> looks pretty
1322 much like any other. You can regard this as totally trivial,
1323 or somewhat profound. However, if you just want to sort the even
1324 digits ahead of the odd ones, then what will
1326 sort { ($a % 2) <=> ($b % 2) } @digits;
1328 yield? The only even digit, C<4>, will come first. But how about
1329 the odd numbers, which all compare equal? With the quicksort algorithm
1330 used to implement Perl 5.6 and earlier, the order of ties is left up
1331 to the sort. So, as you add more and more digits of Pi, the order
1332 in which the sorted even and odd digits appear will change.
1333 and, for sufficiently large slices of Pi, the quicksort algorithm
1334 in Perl 5.8 won't return the same results even if reinvoked with the
1335 same input. The justification for this rests with quicksort's
1336 worst case behavior. If you run
1338 sort { $a <=> $b } ( 1 .. $N , 1 .. $N );
1340 (something you might approximate if you wanted to merge two sorted
1341 arrays using sort), doubling $N doesn't just double the quicksort time,
1342 it I<quadruples> it. Quicksort has a worst case run time that can
1343 grow like N**2, so-called I<quadratic> behaviour, and it can happen
1344 on patterns that may well arise in normal use. You won't notice this
1345 for small arrays, but you I<will> notice it with larger arrays,
1346 and you may not live long enough for the sort to complete on arrays
1347 of a million elements. So the 5.8 quicksort scrambles large arrays
1348 before sorting them, as a statistical defence against quadratic behaviour.
1349 But that means if you sort the same large array twice, ties may be
1350 broken in different ways.
1352 Because of the unpredictability of tie-breaking order, and the quadratic
1353 worst-case behaviour, quicksort was I<almost> replaced completely with
1354 a stable mergesort. I<Stable> means that ties are broken to preserve
1355 the original order of appearance in the input array. So
1357 sort { ($a % 2) <=> ($b % 2) } (3,1,4,1,5,9);
1359 will yield (4,3,1,1,5,9), guaranteed. The even and odd numbers
1360 appear in the output in the same order they appeared in the input.
1361 Mergesort has worst case O(NlogN) behaviour, the best value
1362 attainable. And, ironically, this mergesort does particularly
1363 well where quicksort goes quadratic: mergesort sorts (1..$N, 1..$N)
1364 in O(N) time. But quicksort was rescued at the last moment because
1365 it is faster than mergesort on certain inputs and platforms.
1366 For example, if you really I<don't> care about the order of even
1367 and odd digits, quicksort will run in O(N) time; it's very good
1368 at sorting many repetitions of a small number of distinct elements.
1369 The quicksort divide and conquer strategy works well on platforms
1370 with relatively small, very fast, caches. Eventually, the problem gets
1371 whittled down to one that fits in the cache, from which point it
1372 benefits from the increased memory speed.
1374 Quicksort was rescued by implementing a sort pragma to control aspects
1375 of the sort. The B<stable> subpragma forces stable behaviour,
1376 regardless of algorithm. The B<_quicksort> and B<_mergesort>
1377 subpragmas are heavy-handed ways to select the underlying implementation.
1378 The leading C<_> is a reminder that these subpragmas may not survive
1379 beyond 5.8. More appropriate mechanisms for selecting the implementation
1380 exist, but they wouldn't have arrived in time to save quicksort.
1384 Hashes now use Bob Jenkins "One-at-a-Time" hashing key algorithm
1385 (http://burtleburtle.net/bob/hash/doobs.html). This algorithm is
1386 reasonably fast while producing a much better spread of values than
1387 the old hashing algorithm (originally by Chris Torek, later tweaked by
1388 Ilya Zakharevich). Hash values output from the algorithm on a hash of
1389 all 3-char printable ASCII keys comes much closer to passing the
1390 DIEHARD random number generation tests. According to perlbench, this
1391 change has not affected the overall speed of Perl.
1395 unshift() should now be noticeably faster.
1399 =head1 Installation and Configuration Improvements
1401 =head2 Generic Improvements
1407 INSTALL now explains how you can configure Perl to use 64-bit
1408 integers even on non-64-bit platforms.
1412 Policy.sh policy change: if you are reusing a Policy.sh file
1413 (see INSTALL) and you use Configure -Dprefix=/foo/bar and in the old
1414 Policy $prefix eq $siteprefix and $prefix eq $vendorprefix, all of
1415 them will now be changed to the new prefix, /foo/bar. (Previously
1416 only $prefix changed.) If you do not like this new behaviour,
1417 specify prefix, siteprefix, and vendorprefix explicitly.
1421 A new optional location for Perl libraries, otherlibdirs, is available.
1422 It can be used for example for vendor add-ons without disturbing Perl's
1423 own library directories.
1427 In many platforms the vendor-supplied 'cc' is too stripped-down to
1428 build Perl (basically, 'cc' doesn't do ANSI C). If this seems
1429 to be the case and 'cc' does not seem to be the GNU C compiler
1430 'gcc', an automatic attempt is made to find and use 'gcc' instead.
1434 gcc needs to closely track the operating system release to avoid
1435 build problems. If Configure finds that gcc was built for a different
1436 operating system release than is running, it now gives a clearly visible
1437 warning that there may be trouble ahead.
1441 If binary compatibility with the 5.005 release is not wanted, Configure
1442 no longer suggests including the 5.005 modules in @INC.
1446 Configure C<-S> can now run non-interactively.
1450 Configure support for pdp11-style memory models has been removed due
1455 configure.gnu now works with options with whitespace in them.
1459 installperl now outputs everything to STDERR.
1463 $Config{byteorder} is now computed dynamically (this is more robust
1464 with "fat binaries" where an executable image contains binaries for
1465 more than one binary platform.)
1469 Because PerlIO is now the default on most platforms, "-perlio" doesn't
1470 get appended to the $Config{archname} (also known as $^O) anymore.
1471 Instead, if you explicitly choose not to use perlio (Configure command
1472 line option -Uuseperlio), you will get "-stdio" appended.
1476 Another change related to the architecture name is that "-64all"
1477 (-Duse64bitall, or "maximally 64-bit") is appended only if your
1478 pointers are 64 bits wide. (To be exact, the use64bitall is ignored.)
1482 In AFS installations one can configure the root of the AFS to be
1483 somewhere else than the default F</afs> by using the Configure
1484 parameter C<-Dafsroot=/some/where/else>.
1488 APPLLIB_EXP, a less-know configuration-time definition, has been
1489 documented. It can be used to prepend site-specific directories
1490 to Perl's default search path (@INC), see INSTALL for information.
1494 The version of Berkeley DB used when the Perl (and, presumably, the
1495 DB_File extension) was built is now available as
1496 C<@Config{qw(db_version_major db_version_minor db_version_patch)}>
1497 from Perl and as C<DB_VERSION_MAJOR_CFG DB_VERSION_MINOR_CFG
1498 DB_VERSION_PATCH_CFG> from C.
1502 Building Berkeley DB3 for compatibility modes for DB, NDBM, and ODBM
1503 has been documented in INSTALL.
1507 If you have CPAN access (either network or a local copy such as a
1508 CD-ROM) you can during specify extra modules to Configure to build and
1509 install with Perl using the -Dextras=... option. See INSTALL for
1514 In addition to config.over a new override file, config.arch, is
1515 available. That is supposed to be used by hints file writers for
1516 architecture-wide changes (as opposed to config.over which is for
1521 If your file system supports symbolic links you can build Perl outside
1522 of the source directory by
1524 mkdir /tmp/perl/build/directory
1525 cd /tmp/perl/build/directory
1526 sh /path/to/perl/source/Configure -Dmksymlinks ...
1528 This will create in /tmp/perl/build/directory a tree of symbolic links
1529 pointing to files in /path/to/perl/source. The original files are left
1530 unaffected. After Configure has finished you can just say
1534 and Perl will be built and tested, all in /tmp/perl/build/directory.
1538 For Perl developers several new make targets for profiling
1539 and debugging have been added, see L<perlhack>.
1545 Use of the F<gprof> tool to profile Perl has been documented in
1546 L<perlhack>. There is a make target called "perl.gprof" for
1547 generating a gprofiled Perl executable.
1551 If you have GCC 3, there is a make target called "perl.gcov" for
1552 creating a gcoved Perl executable for coverage analysis. See
1557 If you are on IRIX or Tru64 platforms, new profiling/debugging options
1558 have been added, see L<perlhack> for more information about pixie and
1565 Guidelines of how to construct minimal Perl installations have
1566 been added to INSTALL.
1570 The Thread extension is now not built at all under ithreads
1571 (C<Configure -Duseithreads>) because it wouldn't work anyway (the
1572 Thread extension requires being Configured with C<-Duse5005threads>).
1574 But note that the Thread.pm interface is now shared by both
1579 The Gconvert macro ($Config{d_Gconvert}) used by perl for stringifying
1580 floating-point numbers is now more picky about using sprintf %.*g
1581 rules for the conversion. Some platforms that used to use gcvt may
1582 now resort to the slower sprintf.
1586 =head2 New Or Improved Platforms
1588 For the list of platforms known to support Perl,
1589 see L<perlport/"Supported Platforms">.
1595 AIX dynamic loading should be now better supported.
1599 AIX should now work better with gcc, threads, and 64-bitness. Also the
1600 long doubles support in AIX should be better now. See L<perlaix>.
1604 After a long pause, AmigaOS has been verified to be happy with Perl.
1608 AtheOS (http://www.atheos.cx/) is a new platform.
1612 BeOS has been reclaimed.
1616 DG/UX platform now supports the 5.005-style threads. See L<perldgux>.
1620 DYNIX/ptx platform (a.k.a. dynixptx) is supported at or near osvers 4.5.2.
1624 EBCDIC platforms (z/OS, also known as OS/390, POSIX-BC, and VM/ESA)
1625 have been regained. Many test suite tests still fail and the
1626 co-existence of Unicode and EBCDIC isn't quite settled, but the
1627 situation is much better than with Perl 5.6. See L<perlos390>,
1628 L<perlbs2000> (for POSIX-BC), and L<perlvmesa> for more information.
1632 Building perl with -Duseithreads or -Duse5005threads now works under
1633 HP-UX 10.20 (previously it only worked under 10.30 or later). You will
1634 need a thread library package installed. See README.hpux.
1638 MacOS Classic (MacPerl has of course been available since
1639 perl 5.004 but now the source code bases of standard Perl
1640 and MacPerl have been synchronised)
1644 MacOS X (or Darwin) should now be able to build Perl even on HFS+
1645 filesystems. (The case-insensitivity confused the Perl build process.)
1649 NCR MP-RAS is now supported.
1653 All the NetBSD specific patches (except for the installation
1654 specific ones) have been merged back to the main distribution.
1658 NetWare from Novell is now supported. See L<perlnetware>.
1662 NonStop-UX is now supported.
1666 NEC SUPER-UX is now supported.
1670 All the OpenBSD specific patches (except for the installation
1671 specific ones) have been merged back to the main distribution.
1675 Perl has been tested with the GNU pth userlevel thread package
1676 ( http://www.gnu.org/software/pth/pth.html ) . All but one thread
1677 test worked, and that one failure was because of test results arriving
1678 in unexpected order.
1682 Amdahl UTS UNIX mainframe platform is now supported.
1686 WinCE is now supported. See L<perlce>.
1690 z/OS (formerly known as OS/390, formerly known as MVS OE) has now
1691 support for dynamic loading. This is not selected by default,
1692 however, you must specify -Dusedl in the arguments of Configure.
1696 =head1 Selected Bug Fixes
1698 Numerous memory leaks and uninitialized memory accesses have been
1699 hunted down. Most importantly anonymous subs used to leak quite
1706 The autouse pragma didn't work for Multi::Part::Function::Names.
1710 caller() could cause core dumps in certain situations. Carp was sometimes
1711 affected by this problem.
1715 chop(@list) in list context returned the characters chopped in
1716 reverse order. This has been reversed to be in the right order.
1720 Configure no longer includes the DBM libraries (dbm, gdbm, db, ndbm)
1721 when building the Perl binary. The only exception to this is SunOS 4.x,
1726 The behaviour of non-decimal but numeric string constants such as
1727 "0x23" was platform-dependent: in some platforms that was seen as 35,
1728 in some as 0, in some as a floating point number (don't ask). This
1729 was caused by Perl using the operating system libraries in a situation
1730 where the result of the string to number conversion is undefined: now
1731 Perl consistently handles such strings as zero in numeric contexts.
1735 The order of DESTROYs has been made more predictable.
1739 Several debugger fixes: exit code now reflects the script exit code,
1740 condition C<"0"> now treated correctly, the C<d> command now checks
1741 line number, the C<$.> no longer gets corrupted, all debugger output
1742 now goes correctly to the socket if RemotePort is set.
1746 Perl 5.6.0 could emit spurious warnings about redefinition of dl_error()
1747 when statically building extensions into perl. This has been corrected.
1751 L<dprofpp> -R didn't work.
1755 C<*foo{FORMAT}> now works.
1758 Infinity is now recognized as a number.
1762 UNIVERSAL::isa no longer caches methods incorrectly. (This broke
1763 the Tk extension with 5.6.0.)
1767 Lexicals I: lexicals outside an eval "" weren't resolved
1768 correctly inside a subroutine definition inside the eval "" if they
1769 were not already referenced in the top level of the eval""ed code.
1773 Lexicals II: lexicals leaked at file scope into subroutines that
1774 were declared before the lexicals.
1778 Lexical warnings now propagating correctly between scopes
1779 and into C<eval "...">.
1783 C<use warnings qw(FATAL all)> did not work as intended. This has been
1788 warnings::enabled() now reports the state of $^W correctly if the caller
1789 isn't using lexical warnings.
1793 Line renumbering with eval and C<#line> now works.
1797 Fixed numerous memory leaks, especially in eval "".
1801 mkdir() now ignores trailing slashes in the directory name,
1802 as mandated by POSIX.
1806 Some versions of glibc have a broken modfl(). This affects builds
1807 with C<-Duselongdouble>. This version of Perl detects this brokenness
1808 and has a workaround for it. The glibc release 2.2.2 is known to have
1809 fixed the modfl() bug.
1813 Modulus of unsigned numbers now works (4063328477 % 65535 used to
1814 return 27406, instead of 27047).
1818 Some "not a number" warnings introduced in 5.6.0 eliminated to be
1819 more compatible with 5.005. Infinity is now recognised as a number.
1823 Numeric conversions did not recognize changes in the string value
1824 properly in certain circumstances.
1828 Attributes (like :shared) didn't work with our().
1832 our() variables will not cause "will not stay shared" warnings.
1836 "our" variables of the same name declared in two sibling blocks
1837 resulted in bogus warnings about "redeclaration" of the variables.
1838 The problem has been corrected.
1842 pack "Z" now correctly terminates the string with "\0".
1846 Fix password routines which in some shadow password platforms
1847 (e.g. HP-UX) caused getpwent() to return every other entry.
1851 The PERL5OPT environment variable (for passing command line arguments
1852 to Perl) didn't work for more than a single group of options.
1856 PERL5OPT with embedded spaces didn't work.
1860 printf() no longer resets the numeric locale to "C".
1864 C<qw(a\\b)> now parses correctly as C<'a\\b'>.
1868 pos() did not return the correct value within s///ge in earlier
1869 versions. This is now handled correctly.
1873 Printing quads (64-bit integers) with printf/sprintf now works
1874 without the q L ll prefixes (assuming you are on a quad-capable platform).
1878 Regular expressions on references and overloaded scalars now work.
1882 Right-hand side magic (GMAGIC) could in many cases such as string
1883 concatenation be invoked too many times.
1887 scalar() now forces scalar context even when used in void context.
1891 SOCKS support is now much more robust.
1895 sort() arguments are now compiled in the right wantarray context
1896 (they were accidentally using the context of the sort() itself).
1897 The comparison block is now run in scalar context, and the arguments
1898 to be sorted are always provided list context.
1902 Changed the POSIX character class C<[[:space:]]> to include the (very
1903 rarely used) vertical tab character. Added a new POSIX-ish character
1904 class C<[[:blank:]]> which stands for horizontal whitespace
1905 (currently, the space and the tab).
1909 The tainting behaviour of sprintf() has been rationalized. It does
1910 not taint the result of floating point formats anymore, making the
1911 behaviour consistent with that of string interpolation.
1915 Some cases of inconsistent taint propagation (such as within hash
1916 values) have been fixed.
1920 The RE engine found in Perl 5.6.0 accidentally pessimised certain kinds
1921 of simple pattern matches. These are now handled better.
1925 Regular expression debug output (whether through C<use re 'debug'>
1926 or via C<-Dr>) now looks better.
1930 Multi-line matches like C<"a\nxb\n" =~ /(?!\A)x/m> were flawed. The
1935 Use of $& could trigger a core dump under some situations. This
1940 The regular expression captured submatches ($1, $2, ...) are now
1941 more consistently unset if the match fails, instead of leaving false
1942 data lying around in them.
1946 readline() on files opened in "slurp" mode could return an extra "" at
1947 the end in certain situations. This has been corrected.
1951 Autovivification of symbolic references of special variables described
1952 in L<perlvar> (as in C<${$num}>) was accidentally disabled. This works
1957 Sys::Syslog ignored the C<LOG_AUTH> constant.
1961 All but the first argument of the IO syswrite() method are now optional.
1965 $AUTOLOAD, sort(), lock(), and spawning subprocesses
1966 in multiple threads simultaneously are now thread-safe.
1970 Tie::ARRAY SPLICE method was broken.
1974 Allow read-only string on left hand side of non-modifying tr///.
1978 Several Unicode fixes.
1984 BOMs (byte order marks) in the beginning of Perl files
1985 (scripts, modules) should now be transparently skipped.
1986 UTF-16 (UCS-2) encoded Perl files should now be read correctly.
1990 The character tables have been updated to Unicode 3.1.1.
1994 Comparing with utf8 data does not magically upgrade non-utf8 data
1995 into utf8. (This was a problem for example if you were mixing data
1996 from I/O and Unicode data: your output might have got magically encoded
2001 Generating illegal Unicode code points like U+FFFE, or the UTF-16
2002 surrogates, now also generates an optional warning.
2006 C<IsAlnum>, C<IsAlpha>, and C<IsWord> now match titlecase.
2010 Concatenation with the C<.> operator or via variable interpolation,
2011 C<eq>, C<substr>, C<reverse>, C<quotemeta>, the C<x> operator,
2012 substitution with C<s///>, single-quoted UTF8, should now work.
2016 The C<tr///> operator now works. Note that the C<tr///CU>
2017 functionality has been removed (but see pack('U0', ...)).
2021 C<eval "v200"> now works.
2025 Perl 5.6.0 parsed m/\x{ab}/ incorrectly, leading to spurious warnings.
2026 This has been corrected.
2030 Zero entries were missing from the Unicode classes like C<IsDigit>.
2036 Large unsigned numbers (those above 2**31) could sometimes lose their
2037 unsignedness, causing bogus results in arithmetic operations.
2041 =head2 Platform Specific Changes and Fixes
2049 Perl now works on post-4.0 BSD/OSes.
2055 Setting C<$0> now works (as much as possible; see L<perlvar> for details).
2061 Numerous updates; currently synchronised with Cygwin 1.3.10.
2065 Previously DYNIX/ptx had problems in its Configure probe for non-blocking I/O.
2071 EPOC update after Perl 5.6.0. See README.epoc.
2077 Perl now works on post-3.0 FreeBSDs.
2083 README.hpux updated; C<Configure -Duse64bitall> now works.
2089 Numerous compilation flag and hint enhancements; accidental mixing
2090 of 32-bit and 64-bit libraries (a doomed attempt) made much harder.
2100 Long doubles should now work (see INSTALL).
2104 Linux previously had problems related to sockaddrlen when using
2105 accept(), revcfrom() (in Perl: recv()), getpeername(), and getsockname().
2113 Compilation of the standard Perl distribution in MacOS Classic should
2114 now work if you have the Metrowerks development environment and
2115 the missing Mac-specific toolkit bits. Contact the macperl mailing
2122 MPE/iX update after Perl 5.6.0. See README.mpeix.
2128 Perl now works on NetBSD/sparc.
2134 Now works with usethreads (see INSTALL).
2140 64-bitness using the Sun Workshop compiler now works.
2144 Tru64 (aka Digital UNIX, aka DEC OSF/1)
2146 The operating system version letter now recorded in $Config{osvers}.
2147 Allow compiling with gcc (previously explicitly forbidden). Compiling
2148 with gcc still not recommended because buggy code results, even with
2155 Fixed various alignment problems that lead into core dumps either
2156 during build or later; no longer dies on math errors at runtime;
2157 now using full quad integers (64 bits), previously was using
2158 only 46 bit integers for speed.
2164 chdir() now works better despite a CRT bug; now works with MULTIPLICITY
2165 (see INSTALL); now works with Perl's malloc.
2167 The tainting of C<%ENV> elements via C<keys> or C<values> was previously
2168 unimplemented. It now works as documented.
2170 The C<waitpid> emulation has been improved. The worst bug (now fixed)
2171 was that a pid of -1 would cause a wildcard search of all processes on
2172 the system. The most significant enhancement is that we can now
2173 usually get the completion status of a terminated process.
2175 POSIX-style signals are now emulated much better on VMS versions prior
2178 The C<system> function and backticks operator have improved
2179 functionality and better error handling.
2181 File access tests now use current process privileges rather than the
2182 user's default privileges, which could sometimes result in a mismatch
2183 between reported access and actual access.
2193 accept() no longer leaks memory.
2197 Borland C++ v5.5 is now a supported compiler that can build Perl.
2198 However, the generated binaries continue to be incompatible with those
2199 generated by the other supported compilers (GCC and Visual C++).
2203 Better chdir() return value for a non-existent directory.
2207 Duping socket handles with open(F, ">&MYSOCK") now works under Windows 9x.
2211 New %ENV entries now propagate to subprocesses.
2215 Current directory entries in %ENV are now correctly propagated to child
2220 $ENV{LIB} now used to search for libs under Visual C.
2224 fork() emulation has been improved in various ways, but still continues
2225 to be experimental. See L<perlfork> for known bugs and caveats.
2229 A failed (pseudo)fork now returns undef and sets errno to EAGAIN.
2233 Win32::GetCwd() correctly returns C:\ instead of C: when at the drive root.
2234 Other bugs in chdir() and Cwd::cwd() have also been fixed.
2238 HTML files will be installed in c:\perl\html instead of c:\perl\lib\pod\html
2242 The makefiles now provide a single switch to bulk-enable all the features
2243 enabled in ActiveState ActivePerl (a popular Win32 binary distribution).
2247 Allow REG_EXPAND_SZ keys in the registry.
2251 Can now send() from all threads, not just the first one.
2255 Fake signal handling reenabled, bugs and all.
2259 %SIG has been enabled under USE_ITHREADS, but its use is completely
2260 unsupported under all configurations.
2264 Less stack reserved per thread so that more threads can run
2265 concurrently. (Still 16M per thread.)
2269 C<File::Spec->tmpdir()> now prefers C:/temp over /tmp
2270 (works better when perl is running as service).
2274 Better UNC path handling under ithreads.
2278 wait(), waitpid() and backticks now return the correct exit status under
2283 winsock handle leak fixed.
2287 The Perl parser has been stress tested using both random input and
2288 Markov chain input and the few found crashes and lockups have been
2295 =head1 New or Changed Diagnostics
2301 The lexical warnings category "deprecated" is no longer a sub-category
2302 of the "syntax" category. It is now a top-level category in its own
2307 All regular expression compilation error messages are now hopefully
2308 easier to understand both because the error message now comes before
2309 the failed regex and because the point of failure is now clearly
2310 marked by a C<E<lt>-- HERE> marker.
2314 The various "opened only for", "on closed", "never opened" warnings
2315 drop the C<main::> prefix for filehandles in the C<main> package,
2316 for example C<STDIN> instead of C<main::STDIN>.
2320 The "Unrecognized escape" warning has been extended to include C<\8>,
2321 C<\9>, and C<\_>. There is no need to escape any of the C<\w> characters.
2325 Two new debugging options have been added: if you have compiled your
2326 Perl with debugging, you can use the -DT and -DR options to trace
2327 tokenising and to add reference counts to displaying variables,
2332 perl5db.pl has been modified to present a more consistent commands
2333 interface, via (CommandSet=580). perl5db.t was also added to test the
2334 changes, and as a placeholder for further tests.
2340 The debugger has a new C<dumpDepth> option to control the maximum
2341 depth to which nested structures are dumped. The C<x> command has
2342 been extended so that C<x N EXPR> dumps out the value of I<EXPR> to a
2343 depth of at most I<N> levels.
2347 If an attempt to use a (non-blessed) reference as an array index
2348 is made, a warning is given.
2352 C<push @a;> and C<unshift @a;> (with no values to push or unshift)
2353 now give a warning. This may be a problem for generated and evaled
2358 If you try to L<perlfunc/pack> a number less than 0 or larger than 255
2359 using the C<"C"> format you will get an optional warning. Similarly
2360 for the C<"c"> format and a number less than -128 or more than 127.
2364 Certain regex modifiers such as C<(?o)> make sense only if applied to
2365 the entire regex. You will an optional warning if you try to do otherwise.
2369 Using arrays or hashes as references (e.g. C<< %foo->{bar} >>
2370 has been deprecated for a while. Now you will get an optional warning.
2374 =head1 Changed Internals
2380 perlapi.pod (a companion to perlguts) now attempts to document the
2385 You can now build a really minimal perl called microperl.
2386 Building microperl does not require even running Configure;
2387 C<make -f Makefile.micro> should be enough. Beware: microperl makes
2388 many assumptions, some of which may be too bold; the resulting
2389 executable may crash or otherwise misbehave in wondrous ways.
2390 For careful hackers only.
2394 Added rsignal(), whichsig(), do_join(), op_clear, op_null,
2395 ptr_table_clear(), ptr_table_free(), sv_setref_uv(), and several UTF-8
2396 interfaces to the publicised API. For the full list of the available
2397 APIs see L<perlapi>.
2401 Made possible to propagate customised exceptions via croak()ing.
2405 Now xsubs can have attributes just like subs. (Well, at least the
2406 built-in attributes.)
2410 dTHR and djSP have been obsoleted; the former removed (because it's
2411 a no-op) and the latter replaced with dSP.
2415 PERL_OBJECT has been completely removed.
2419 The MAGIC constants (e.g. C<'P'>) have been macrofied
2420 (e.g. C<PERL_MAGIC_TIED>) for better source code readability
2421 and maintainability.
2425 The regex compiler now maintains a structure that identifies nodes in
2426 the compiled bytecode with the corresponding syntactic features of the
2427 original regex expression. The information is attached to the new
2428 C<offsets> member of the C<struct regexp>. See L<perldebguts> for more
2429 complete information.
2433 The C code has been made much more C<gcc -Wall> clean. Some warning
2434 messages still remain in some platforms, so if you are compiling with
2435 gcc you may see some warnings about dubious practices. The warnings
2436 are being worked on.
2440 F<perly.c>, F<sv.c>, and F<sv.h> have now been extensively commented.
2444 Documentation on how to use the Perl source repository has been added
2445 to F<Porting/repository.pod>.
2449 There are now several profiling make targets.
2453 =head1 Security Vulnerability Closed
2455 (This change was already made in 5.7.0 but bears repeating here.)
2457 A potential security vulnerability in the optional suidperl component
2458 of Perl was identified in August 2000. suidperl is neither built nor
2459 installed by default. As of November 2001 the only known vulnerable
2460 platform is Linux, most likely all Linux distributions. CERT and
2461 various vendors and distributors have been alerted about the vulnerability.
2462 See http://www.cpan.org/src/5.0/sperl-2000-08-05/sperl-2000-08-05.txt
2463 for more information.
2465 The problem was caused by Perl trying to report a suspected security
2466 exploit attempt using an external program, /bin/mail. On Linux
2467 platforms the /bin/mail program had an undocumented feature which
2468 when combined with suidperl gave access to a root shell, resulting in
2469 a serious compromise instead of reporting the exploit attempt. If you
2470 don't have /bin/mail, or if you have 'safe setuid scripts', or if
2471 suidperl is not installed, you are safe.
2473 The exploit attempt reporting feature has been completely removed from
2474 Perl 5.8.0 (and the maintenance release 5.6.1, and it was removed also
2475 from all the Perl 5.7 releases), so that particular vulnerability
2476 isn't there anymore. However, further security vulnerabilities are,
2477 unfortunately, always possible. The suidperl functionality is most
2478 probably going to be removed in Perl 5.10. In any case, suidperl
2479 should only be used by security experts who know exactly what they are
2480 doing and why they are using suidperl instead of some other solution
2481 such as sudo (see http://www.courtesan.com/sudo/).
2485 Several new tests have been added, especially for the F<lib>
2486 subsection. There are now about 56 000 individual tests (spread over
2487 about 620 test scripts), in the regression suite (5.6.1 has about
2488 11700 tests, in 258 test scripts) Many of the new tests are introduced
2489 by the new modules, but still in general Perl is now more thoroughly
2492 Because of the large number of tests, running the regression suite
2493 will take considerably longer time than it used to: expect the suite
2494 to take up to 4-5 times longer to run than in perl 5.6. In a really
2495 fast machine you can hope to finish the suite in about 6-8 minutes
2498 The tests are now reported in a different order than in earlier Perls.
2499 (This happens because the test scripts from under t/lib have been moved
2500 to be closer to the library/extension they are testing.)
2502 =head1 Known Problems
2510 In AIX 4.2 Perl extensions that use C++ functions that use statics
2511 may have problems in that the statics are not getting initialized.
2512 In newer AIX releases this has been solved by linking Perl with
2513 the libC_r library, but unfortunately in AIX 4.2 the said library
2514 has an obscure bug where the various functions related to time
2515 (such as time() and gettimeofday()) return broken values, and
2516 therefore in AIX 4.2 Perl is not linked against the libC_r.
2520 vac 5.0.0.0 May Produce Buggy Code For Perl
2522 The AIX C compiler vac version 5.0.0.0 may produce buggy code,
2523 resulting in few random tests failing, but when the failing tests
2524 are run by hand, they succeed. We suggest upgrading to at least
2525 vac version 5.0.1.0, that has been known to compile Perl correctly.
2526 "lslpp -L|grep vac.C" will tell you the vac version. See README.aix.
2530 =head2 Amiga Perl Invoking Mystery
2532 One cannot call Perl using the C<volume:> syntax, that is, C<perl -v>
2533 works, but for example C<bin:perl -v> doesn't. The exact reason isn't
2534 known but the current suspect is the F<ixemul> library.
2536 =head2 lib/ftmp-security tests warn 'system possibly insecure'
2538 Don't panic. Read INSTALL 'make test' section instead.
2540 =head2 FreeBSD 4.3, 4.4, 4.5 fail lib/File/Spec/t/rel2abs2rel.t
2542 F<lib/File/Spec/t/rel2abs2rel.t> tests that "`` works" by running a a perl 1
2543 liner in backticks, using "$^X" as the path to perl. It is known to be
2544 failing on FreeBSD 4.3, 4.4 and 4.5, but only when run as part of make test.
2545 This seems to be a kernel problem rather than perl - reading the symlink
2546 F</proc/curproc/file> returns "unknown" rather than the path to perl, and a
2547 kernel debugger reveals that variable C<numfullpathfail2> in
2548 F</usr/src/sys/kern/vfs_cache.c> is being incremented whenever
2549 F</proc/curproc/file> fails to return the perl executable's path.
2550 [If you find that if fails on other versions of FreeBSD, please use perlbug
2551 to report them to us. If you are able to fix the bug, even better.]
2553 =head2 HP-UX lib/posix Subtest 9 Fails When LP64-Configured
2555 If perl is configured with -Duse64bitall, the successful result of the
2556 subtest 10 of lib/posix may arrive before the successful result of the
2557 subtest 9, which confuses the test harness so much that it thinks the
2560 =head2 Linux With Sfio Fails op/misc Test 48
2566 The following tests are known to fail:
2568 Failed Test Stat Wstat Total Fail Failed List of Failed
2569 -------------------------------------------------------------------------
2570 ../ext/DB_File/t/db-btree.t 0 11 ?? ?? % ??
2571 ../ext/DB_File/t/db-recno.t 149 3 2.01% 61 63 65
2572 ../ext/POSIX/t/posix.t 31 1 3.23% 10
2574 If you are building on a UFS partition, you will also probably see
2577 ext/POSIX/t/posix...................FAILED at test 10
2579 This is caused by Darwin's UFS not supporting inode change time.
2583 OS/390 has rather many test failures but the situation is actually
2584 better than it was in 5.6.0, it's just that so many new modules and
2585 tests have been added.
2587 ../ext/B/t/deparse.t 17 1 5.88% 14
2588 ../ext/IO/lib/IO/t/io_unix.t 5 4 80.00% 2-5
2589 ../lib/utf8.t 94 13 13.83% 27 30-31 43 46 73
2592 ../lib/Benchmark.t 1 256 159 1 0.63% 75
2593 ../lib/ExtUtils/t/Embed.t 9 9 100.00% 1-9
2594 ../lib/ExtUtils/t/ExtUtils.t 27 19 70.37% 5-23
2595 op/pat.t 858 9 1.05% 242-243 665 776 785
2597 op/sprintf.t 224 3 1.34% 98 100 136
2598 op/tr.t 97 5 5.15% 63 71-74
2599 uni/fold.t 767 8 1.04% 25-26 62 169 196
2601 57 tests and 377 subtests skipped.
2603 =head2 op/sprintf tests 129 and 130
2605 The op/sprintf tests 129 and 130 are known to fail on some platforms.
2606 Examples include any platform using sfio, and Compaq/Tandem's NonStop-UX.
2607 The failing platforms do not comply with the ANSI C Standard, line
2608 19ff on page 134 of ANSI X3.159 1989 to be exact. (They produce
2609 something other than "1" and "-1" when formatting 0.6 and -0.6 using
2610 the printf format "%.0f", most often they produce "0" and "-0".)
2612 =head2 Failure of Thread tests
2614 B<Note that support for 5.005-style threading remains experimental
2615 and practically unsupported.>
2617 The following tests are known to fail due to fundamental problems in
2618 the 5.005 threading implementation. These are not new failures--Perl
2619 5.005_0x has the same bugs, but didn't have these tests.
2621 ../ext/List/Util/t/first.t 255 65280 7 4 57.14% 2 5-7
2622 ../lib/English.t 2 512 54 2 3.70% 2-3
2623 ../lib/Filter/Simple/t/data.t 6 3 50.00% 1-3
2624 ../lib/Filter/Simple/t/filter_onl 9 3 33.33% 1-2 5
2625 ../lib/autouse.t 10 1 10.00% 4
2626 op/flip.t 15 1 6.67% 15
2628 These failures are unlikely to get fixed as the 5.005-style
2629 threads are considered fundamentally broken.
2633 ../ext/Socket/socketpair.t 1 256 45 1 2.22% 12
2634 ../lib/Math/Trig.t 26 1 3.85% 25
2635 ../lib/warnings.t 460 1 0.22% 425
2636 io/fs.t 36 1 2.78% 31
2637 op/numconvert.t 1440 13 0.90% 208 509-510
2638 657-658 665-666 829-830 989-990 1149-1150
2640 =head2 UNICOS and UNICOS/mk
2642 The io/fs test #31 is failing because in UNICOS and UNICOS/mk
2643 truncate() cannot be used to grow the size of filehandles, only
2644 to reduce the size. The workaround is to truncate files instead
2649 There are a few known test failures, see L<perluts>.
2653 There should be no reported test failures with a default configuration,
2654 though there are a number of tests marked TODO that point to areas
2655 needing further debugging and/or porting work.
2659 In multi-CPU boxes there are some problems with the I/O buffering:
2660 some output may appear twice. The Win32 following failures are known
2663 ..\ext/Encode/t/JP.t 4 1024 22 4 18.18% 9 14 18 21
2664 ..\ext/threads/t/end.t 6 4 66.67% 3-6
2665 ..\lib/blib.t 3 768 7 3 42.86% 1 4-5
2667 =head2 Localising a Tied Variable Leaks Memory
2670 tie my %tie_hash => 'Tie::StdHash';
2674 local($tie_hash{Foo}) = 1; # leaks
2676 Code like the above is known to leak memory every time the local()
2679 =head2 Localising Tied Arrays and Hashes Is Broken
2683 doesn't work as one would expect: the old value is restored
2686 =head2 Self-tying of Arrays and Hashes Is Forbidden
2688 Self-tying of arrays and hashes is broken in rather deep and
2689 hard-to-fix ways. As a stop-gap measure to avoid people from getting
2690 frustrated at the mysterious results (core dumps, most often) it is
2691 for now forbidden (you will get a fatal error even from an attempt).
2693 =head2 Building Extensions Can Fail Because Of Largefiles
2695 Some extensions like mod_perl are known to have issues with
2696 `largefiles', a change brought by Perl 5.6.0 in which file offsets
2697 default to 64 bits wide, where supported. Modules may fail to compile
2698 at all or compile and work incorrectly. Currently there is no good
2699 solution for the problem, but Configure now provides appropriate
2700 non-largefile ccflags, ldflags, libswanted, and libs in the %Config
2701 hash (e.g., $Config{ccflags_nolargefiles}) so the extensions that are
2702 having problems can try configuring themselves without the
2703 largefileness. This is admittedly not a clean solution, and the
2704 solution may not even work at all. One potential failure is whether
2705 one can (or, if one can, whether it's a good idea) link together at
2706 all binaries with different ideas about file offsets, all this is
2709 =head2 Unicode Support on EBCDIC Still Spotty
2711 Though mostly working, Unicode support still has problem spots on
2712 EBCDIC platforms. One such known spot are the C<\p{}> and C<\P{}>
2713 regular expression constructs for code points less than 256: the
2714 pP are testing for Unicode code points, not knowing about EBCDIC.
2716 =head2 The Compiler Suite Is Still Experimental
2718 The compiler suite is slowly getting better but it continues to be
2719 highly experimental. Use in production environments is discouraged.
2721 =head2 The Long Double Support Is Still Experimental
2723 The ability to configure Perl's numbers to use "long doubles",
2724 floating point numbers of hopefully better accuracy, is still
2725 experimental. The implementations of long doubles are not yet
2726 widespread and the existing implementations are not quite mature
2727 or standardised, therefore trying to support them is a rare
2728 and moving target. The gain of more precision may also be offset
2729 by slowdown in computations (more bits to move around, and the
2730 operations are more likely to be executed by less optimised
2733 =head2 Seen In Perl 5.7 But Gone Now
2735 C<Time::Piece> (previously known as C<Time::Object>) was removed
2736 because it was felt that it didn't have enough value in it to be a
2737 core module. It is still a useful module, though, and is available
2740 =head1 Reporting Bugs
2742 If you find what you think is a bug, you might check the articles
2743 recently posted to the comp.lang.perl.misc newsgroup and the perl
2744 bug database at http://bugs.perl.org. There may also be
2745 information at http://www.perl.com/, the Perl Home Page.
2747 If you believe you have an unreported bug, please run the B<perlbug>
2748 program included with your release. Be sure to trim your bug down
2749 to a tiny but sufficient test case. Your bug report, along with the
2750 output of C<perl -V>, will be sent off to perlbug@perl.org to be
2751 analysed by the Perl porting team.
2755 The F<Changes> file for exhaustive details on what changed.
2757 The F<INSTALL> file for how to build Perl.
2759 The F<README> file for general stuff.
2761 The F<Artistic> and F<Copying> files for copyright information.
2765 Written by Jarkko Hietaniemi <F<jhi@iki.fi>>.