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
210 available. The I<restricted hashes> interface is expected to
211 be the replacement interface (see L<Hash::Util>).
215 The syntaxes C<< @a->[...] >> and C<< %h->{...} >> have now been deprecated.
219 After years of trying the suidperl is considered to be too complex to
220 ever be considered truly secure. The suidperl functionality is likely
221 to be removed in a future release.
225 The long deprecated uppercase aliases for the string comparison
226 operators (EQ, NE, LT, LE, GE, GT) have now been removed.
230 The tr///C and tr///U features have been removed and will not return;
231 the interface was a mistake. Sorry about that. For similar
232 functionality, see pack('U0', ...) and pack('C0', ...).
236 Earlier Perls treated "sub foo (@bar)" as equivalent to "sub foo (@)".
237 The prototypes are now checked at compile-time for invalid characters.
238 An optional warning is generated ("Illegal character in prototype...")
239 but this may be upgraded to a fatal error in a future release.
243 =head1 Core Enhancements
245 =head2 PerlIO is Now The Default
251 IO is now by default done via PerlIO rather than system's "stdio".
252 PerlIO allows "layers" to be "pushed" onto a file handle to alter the
253 handle's behaviour. Layers can be specified at open time via 3-arg
256 open($fh,'>:crlf :utf8', $path) || ...
258 or on already opened handles via extended C<binmode>:
260 binmode($fh,':encoding(iso-8859-7)');
262 The built-in layers are: unix (low level read/write), stdio (as in
263 previous Perls), perlio (re-implementation of stdio buffering in a
264 portable manner), crlf (does CRLF <=> "\n" translation as on Win32,
265 but available on any platform). A mmap layer may be available if
266 platform supports it (mostly UNIXes).
268 Layers to be applied by default may be specified via the 'open' pragma.
270 See L</"Installation and Configuration Improvements"> for the effects
271 of PerlIO on your architecture name.
275 File handles can be marked as accepting Perl's internal encoding of Unicode
276 (UTF-8 or UTF-EBCDIC depending on platform) by a pseudo layer ":utf8" :
278 open($fh,">:utf8","Uni.txt");
280 Note for EBCDIC users: the pseudo layer ":utf8" is erroneously named
281 for you since it's not UTF-8 what you will be getting but instead
282 UTF-EBCDIC. See L<perlunicode>, L<utf8>, and
283 http://www.unicode.org/unicode/reports/tr16/ for more information.
284 In future releases this naming may change.
288 File handles can translate character encodings from/to Perl's internal
289 Unicode form on read/write via the ":encoding()" layer.
293 File handles can be opened to "in memory" files held in Perl scalars via:
295 open($fh,'>', \$variable) || ...
299 Anonymous temporary files are available without need to
300 'use FileHandle' or other module via
302 open($fh,"+>", undef) || ...
304 That is a literal undef, not an undefined value.
308 The list form of C<open> is now implemented for pipes (at least on UNIX):
310 open($fh,"-|", 'cat', '/etc/motd')
312 creates a pipe, and runs the equivalent of exec('cat', '/etc/motd') in
317 If your locale environment variables (LANGUAGE, LC_ALL, LC_CTYPE, LANG)
318 contain the strings 'UTF-8' or 'UTF8' (case-insensitive matching),
319 the default encoding of your STDIN, STDOUT, and STDERR, and of
320 B<any subsequent file open>, is UTF-8.
326 Perl used to be fragile in that signals arriving at inopportune moments
327 could corrupt Perl's internal state. Now Perl postpones handling of
328 signals until it's safe (between opcodes).
330 This change may have surprising side effects because signals no longer
331 interrupt Perl instantly. Perl will now first finish whatever it was
332 doing, like finishing an internal operation (like sort()) or an
333 external operation (like an I/O operation), and only then look at any
334 arrived signals (and before starting the next operation). No more corrupt
335 internal state since the current operation is always finished first,
336 but the signal may take more time to get heard. Note that breaking
337 out from potentially blocking operations should still work, though.
339 =head2 Unicode Overhaul
341 Unicode in general should be now much more usable than in Perl 5.6.0
342 (or even in 5.6.1). Unicode can be used in hash keys, Unicode in
343 regular expressions should work now, Unicode in tr/// should work now,
344 Unicode in I/O should work now. See L<perluniintro> for introduction
345 and L<perlunicode> for details.
351 The Unicode Character Database coming with Perl has been upgraded
352 to Unicode 3.2.0. For more information, see http://www.unicode.org/ .
356 For developers interested in enhancing Perl's Unicode capabilities:
357 almost all the UCD files are included with the Perl distribution in
358 the F<lib/unicore subdirectory>. The most notable omission, for space
359 considerations, is the Unihan database.
363 The properties \p{Blank} and \p{SpacePerl} have been added. "Blank" is like
364 C isblank(), that is, it contains only "horizontal whitespace" (the space
365 character is, the newline isn't), and the "SpacePerl" is the Unicode
366 equivalent of C<\s> (\p{Space} isn't, since that includes the vertical
367 tabulator character, whereas C<\s> doesn't.)
369 See "New Unicode Properties" earlier in this document for additional
370 information on changes with Unicode properties.
374 =head2 Understanding of Numbers
376 In general a lot of fixing has happened in the area of Perl's
377 understanding of numbers, both integer and floating point. Since in
378 many systems the standard number parsing functions like C<strtoul()>
379 and C<atof()> seem to have bugs, Perl tries to work around their
380 deficiencies. This results hopefully in more accurate numbers.
382 Perl now tries internally to use integer values in numeric conversions
383 and basic arithmetics (+ - * /) if the arguments are integers, and
384 tries also to keep the results stored internally as integers.
385 This change leads to often slightly faster and always less lossy
386 arithmetics. (Previously Perl always preferred floating point numbers
389 =head2 Miscellaneous Changes
395 AUTOLOAD is now lvaluable, meaning that you can add the :lvalue attribute
396 to AUTOLOAD subroutines and you can assign to the AUTOLOAD return value.
400 C<perl -d:Module=arg,arg,arg> now works (previously one couldn't pass
401 in multiple arguments.)
405 The builtin dump() now gives an optional warning
406 C<dump() better written as CORE::dump()>,
407 meaning that by default C<dump(...)> is resolved as the builtin
408 dump() which dumps core and aborts, not as (possibly) user-defined
409 C<sub dump>. To call the latter, qualify the call as C<&dump(...)>.
410 (The whole dump() feature is to considered deprecated, and possibly
411 removed/changed in future releases.)
415 chomp() and chop() are now overridable. Note, however, that their
416 prototype (as given by C<prototype("CORE::chomp")> is undefined,
417 because it cannot be expressed and therefore one cannot really write
418 replacements to override these builtins.
422 END blocks are now run even if you exit/die in a BEGIN block.
423 Internally, the execution of END blocks is now controlled by
424 PL_exit_flags & PERL_EXIT_DESTRUCT_END. This enables the new
425 behaviour for Perl embedders. This will default in 5.10. See
430 Formats now support zero-padded decimal fields.
434 Lvalue subroutines can now return C<undef> in list context.
435 However, the lvalue subroutine feature still remains experimental.
439 A lost warning "Can't declare ... dereference in my" has been
440 restored (Perl had it earlier but it became lost in later releases.)
444 A new special regular expression variable has been introduced:
445 C<$^N>, which contains the most-recently closed group (submatch).
449 C<no Module;> now works even if there is no "sub unimport" in the Module.
453 The numerical comparison operators return C<undef> if either operand
454 is a NaN. Previously the behaviour was unspecified.
458 The following builtin functions are now overridable: each(), keys(),
459 pop(), push(), shift(), splice(), unshift().
463 C<pack() / unpack()> now can group template letters with C<()> and then
464 apply repetition/count modifiers on the groups.
468 C<pack() / unpack()> can now process the Perl internal numeric types:
469 IVs, UVs, NVs-- and also long doubles, if supported by the platform.
470 The template letters are C<j>, C<J>, C<F>, and C<D>.
474 C<pack('U0a*', ...)> can now be used to force a string to UTF8.
478 my __PACKAGE__ $obj now works.
482 The printf() and sprintf() now support parameter reordering using the
483 C<%\d+\$> and C<*\d+\$> syntaxes. For example
485 print "%2\$s %1\$s\n", "foo", "bar";
487 will print "bar foo\n". This feature helps in writing
488 internationalised software, and in general when the order
489 of the parameters can vary.
493 prototype(\&) is now available.
497 prototype(\[$@%&]) is now available to implicitly create references
498 (useful for example if you want to emulate the tie() interface).
502 A new command-line option, C<-t> is available. It is the
503 little brother of C<-T>: instead of dying on taint violations,
504 lexical warnings are given. B<This is only meant as a temporary
505 debugging aid while securing the code of old legacy applications.
506 This is not a substitute for -T.>
510 In other taint news, the C<exec LIST> and C<system LIST> have now been
511 considered too risky (think C<exec @ARGV>: it can start any program
512 with any arguments), and now the said forms cause a warning.
513 You should carefully launder the arguments to guarantee their
514 validity. In future releases of Perl the forms will become fatal
515 errors so consider starting laundering now.
519 If tr/// is just counting characters, it doesn't attempt to
524 untie() will now call an UNTIE() hook if it exists. See L<perltie>
529 L<utime> now supports C<utime undef, undef, @files> to change the
530 file timestamps to the current time.
534 The rules for allowing underscores (underbars) in numeric constants
535 have been relaxed and simplified: now you can have an underscore
536 simply B<between digits>.
540 Rather than relying on C's argv[0] (which may not contain a full pathname)
541 where possible $^X is now set by asking the operating system.
542 (eg by reading F</proc/self/exe> on Linux, F</proc/curproc/file> on FreeBSD)
546 A new variable, C<${^TAINT}>, indicates whether taint mode is enabled.
550 You can now override the readline() builtin, and this overrides also
551 the <FILEHANDLE> angle bracket operator.
555 The command-line options -s and -F are now recognized on the shebang
560 Use of the C</c> match modifier without an accompanying C</g> modifier
561 elicits a new warning: C<Use of /c modifier is meaningless without /g>.
563 Use of C</c> in substitutions, even with C</g>, elicits
564 C<Use of /c modifier is meaningless in s///>.
566 Use of C</g> with C<split> elicits C<Use of /g modifier is meaningless
571 =head1 Modules and Pragmata
573 =head2 New Modules and Pragmata
579 C<Attribute::Handlers> allows a class to define attribute handlers.
582 use Attribute::Handlers;
583 sub Wolf :ATTR(SCALAR) { print "howl!\n" }
585 # later, in some package using or inheriting from MyPack...
587 my MyPack $Fluffy : Wolf; # the attribute handler Wolf will be called
589 Both variables and routines can have attribute handlers. Handlers can
590 be specific to type (SCALAR, ARRAY, HASH, or CODE), or specific to the
591 exact compilation phase (BEGIN, CHECK, INIT, or END).
595 B<B::Concise> is a new compiler backend for walking the Perl syntax
596 tree, printing concise info about ops, from Stephen McCamant. The
597 output is highly customisable. See L<B::Concise>.
601 The new bignum, bigint, and bigrat pragmas implement transparent
602 bignum support (using the Math::BigInt, Math::BigFloat, and
603 Math::BigRat backends), by Tels.
607 C<Class::ISA> for reporting the search path for a class's ISA tree,
608 by Sean Burke, has been added. See L<Class::ISA>.
612 C<Cwd> has now a split personality: if possible, an XS extension is
613 used, (this will hopefully be faster, more secure, and more robust)
614 but if not possible, the familiar Perl implementation is used.
618 C<Devel::PPPort>, originally from Kenneth Albanowski and now
619 maintained by Paul Marquess, has been added. It is primarily used
620 by C<h2xs> to enhance portability of XS modules between different
625 C<Digest>, frontend module for calculating digests (checksums), from
626 Gisle Aas, has been added. See L<Digest>.
630 C<Digest::MD5> for calculating MD5 digests (checksums) as defined in
631 RFC 1321, from Gisle Aas, has been added. See L<Digest::MD5>.
633 use Digest::MD5 'md5_hex';
635 $digest = md5_hex("Thirsty Camel");
637 print $digest, "\n"; # 01d19d9d2045e005c3f1b80e8b164de1
639 NOTE: the C<MD5> backward compatibility module is deliberately not
640 included since its further use is discouraged.
644 C<Encode>, by Nick Ing-Simmons and Dan Kogai, provides a mechanism to
645 translate between different character encodings. Support for Unicode,
646 ISO-8859-1, and ASCII are compiled in to the module. Several other
647 encodings (like the rest of the ISO-8859, CP*/Win*, Mac, KOI8-R, three
648 variants EBCDIC, Chinese, Japanese, and Korean encodings) are included
649 and can be loaded at runtime. (For space considerations, the largest
650 Chinese encodings have been separated into their own CPAN module,
651 Encode::HanExtra, which Encode will use if available). See L<Encode>.
653 Any encoding supported by Encode module is also available to the
654 ":encoding()" layer if PerlIO is used.
658 C<Hash::Util> is the interface to the new I<restricted hashes>
659 feature. A restricted hash is restricted to a certain set of keys,
660 no keys outside the set can be added. Also individual keys can be
661 restricted so that the key cannot be deleted and the value cannot be
662 changed. (Implemented by Jeffrey Friedl, Nick Ing-Simmons, and
667 C<I18N::Langinfo> can be use to query locale information.
668 See L<I18N::Langinfo>.
672 C<I18N::LangTags> has functions for dealing with RFC3066-style
673 language tags, by Sean Burke. See L<I18N::LangTags>.
677 C<ExtUtils::Constant> is a new tool for extension writers for
678 generating XS code to import C header constants, by Nicholas Clark.
679 See L<ExtUtils::Constant>.
683 C<Filter::Simple> is an easy-to-use frontend to Filter::Util::Call,
684 from Damian Conway. See L<Filter::Simple>.
690 use Filter::Simple sub {
691 while (my ($from, $to) = splice @_, 0, 2) {
700 use MyFilter qr/red/ => 'green';
702 print "red\n"; # this code is filtered, will print "green\n"
703 print "bored\n"; # this code is filtered, will print "bogreen\n"
707 print "red\n"; # this code is not filtered, will print "red\n"
711 C<File::Temp> allows one to create temporary files and directories in
712 an easy, portable, and secure way, by Tim Jenness. See L<File::Temp>.
716 C<Filter::Util::Call> provides you with the framework to write
717 I<Source Filters> in Perl, from Paul Marquess. For most uses the
718 frontend Filter::Simple is to be preferred. See L<Filter::Util::Call>.
722 C<if> is a new pragma for conditional inclusion of modules, from
727 L<libnet> is a collection of perl5 modules related to network
728 programming, from Graham Barr. See L<Net::FTP>, L<Net::NNTP>,
729 L<Net::Ping> (not part of libnet, but related), L<Net::POP3>,
730 L<Net::SMTP>, and L<Net::Time>.
732 Perl installation leaves libnet unconfigured, use F<libnetcfg> to configure.
736 C<List::Util> is a selection of general-utility list subroutines, like
737 sum(), min(), first(), and shuffle(), by Graham Barr. See L<List::Util>.
741 C<Locale::Constants>, C<Locale::Country>, C<Locale::Currency>, and
742 C<Locale::Language>, from Neil Bowers, have been added. They provide the
743 codes for various locale standards, such as "fr" for France, "usd" for
744 US Dollar, and "jp" for Japanese.
748 $country = code2country('jp'); # $country gets 'Japan'
749 $code = country2code('Norway'); # $code gets 'no'
751 See L<Locale::Constants>, L<Locale::Country>, L<Locale::Currency>,
752 and L<Locale::Language>.
756 C<Locale::Maketext> is localization framework from Sean Burke. See
757 L<Locale::Maketext>, and L<Locale::Maketext::TPJ13>. The latter is an
758 article about software localization, originally published in The Perl
759 Journal #13, republished here with kind permission.
763 Math::BigRat for big rational numbers, to accompany Math::BigInt and
764 Math::BigFloat, from Tels.
768 C<Memoize> can make your functions faster by trading space for time,
769 from Mark-Jason Dominus. See L<Memoize>.
773 C<MIME::Base64> allows you to encode data in base64, from Gisle Aas,
774 as defined in RFC 2045 - I<MIME (Multipurpose Internet Mail
779 $encoded = encode_base64('Aladdin:open sesame');
780 $decoded = decode_base64($encoded);
782 print $encoded, "\n"; # "QWxhZGRpbjpvcGVuIHNlc2FtZQ=="
788 C<MIME::QuotedPrint> allows you to encode data in quoted-printable
789 encoding, as defined in RFC 2045 - I<MIME (Multipurpose Internet Mail
790 Extensions)>, from Gisle Aas.
792 use MIME::QuotedPrint;
794 $encoded = encode_qp("Smiley in Unicode: \x{263a}");
795 $decoded = decode_qp($encoded);
797 print $encoded, "\n"; # "Smiley in Unicode: =263A"
799 MIME::QuotedPrint has been enhanced to provide the basic methods
800 necessary to use it with PerlIO::Via as in :
802 use MIME::QuotedPrint;
803 open($fh,">Via(MIME::QuotedPrint)",$path);
805 See L<MIME::QuotedPrint>.
809 C<NEXT> is pseudo-class for method redispatch, from Damian Conway.
814 C<open> is a new pragma for setting the default I/O disciplines
819 C<PerlIO::Scalar> provides the implementation of IO to "in memory"
820 Perl scalars as discussed above, from Nick Ing-Simmons. It also
821 serves as an example of a loadable PerlIO layer. Other future
822 possibilities include PerlIO::Array and PerlIO::Code.
823 See L<PerlIO::Scalar>.
827 C<PerlIO::Via> acts as a PerlIO layer and wraps PerlIO layer
828 functionality provided by a class (typically implemented in perl
829 code), from Nick Ing-Simmons.
831 use MIME::QuotedPrint;
832 open($fh,">Via(MIME::QuotedPrint)",$path);
834 This will automatically convert everything output to C<$fh>
835 to Quoted-Printable. See L<PerlIO::Via>.
839 C<Pod::ParseLink>, by Russ Allbery, has been added,
840 to parse LZ<><> links in pods as described in the new
845 C<Pod::Text::Overstrike>, by Joe Smith, has been added.
846 It converts POD data to formatted overstrike text.
847 See L<Pod::Text::Overstrike>.
851 C<Scalar::Util> is a selection of general-utility scalar subroutines,
852 like blessed(), reftype(), and tainted(). See L<Scalar::Util>.
856 C<sort> is a new pragma for controlling the behaviour of sort().
860 C<Storable> gives persistence to Perl data structures by allowing the
861 storage and retrieval of Perl data to and from files in a fast and
862 compact binary format, from Raphael Manfredi. See L<Storable>.
866 C<Switch>, from Damian Conway, has been added. Just by saying
870 you have C<switch> and C<case> available in Perl.
876 case 1 { print "number 1" }
877 case "a" { print "string a" }
878 case [1..10,42] { print "number in list" }
879 case (@array) { print "number in list" }
880 case /\w+/ { print "pattern" }
881 case qr/\w+/ { print "pattern" }
882 case (%hash) { print "entry in hash" }
883 case (\%hash) { print "entry in hash" }
884 case (\&sub) { print "arg to subroutine" }
885 else { print "previous case not true" }
892 C<Test::More> is yet another framework for writing test scripts,
893 more extensive than Test::Simple, by Michael Schwern. See L<Test::More>.
897 C<Test::Simple> has basic utilities for writing tests, by Michael
898 Schwern. See L<Test::Simple>.
902 C<Text::Balanced> has been added, for extracting delimited text
903 sequences from strings, from Damian Conway.
905 use Text::Balanced 'extract_delimited';
907 ($a, $b) = extract_delimited("'never say never', he never said", "'", '');
909 $a will be "'never say never'", $b will be ', he never said'.
911 In addition to extract_delimited() there are also extract_bracketed(),
912 extract_quotelike(), extract_codeblock(), extract_variable(),
913 extract_tagged(), extract_multiple(), gen_delimited_pat(), and
914 gen_extract_tagged(). With these you can implement rather advanced
915 parsing algorithms. See L<Text::Balanced>.
919 C<threads> is an interface to interpreter threads, by Arthur Bergman.
920 Interpreter threads (ithreads) is the new thread model introduced in
921 Perl 5.6 but only available as an internal interface for extension
922 writers (and for Win32 Perl for C<fork()> emulation). See L<threads>.
926 C<threads::shared> allows data sharing for interpreter threads, from
927 Arthur Bergman. In the ithreads model any data sharing between
928 threads must be explicit, as opposed to the old 5.005 thread model
929 where data sharing was implicit. See L<threads::shared>.
933 C<Tie::File>, by Mark-Jason Dominus, associates a Perl array with the
938 C<Tie::Memoize>, by Ilya Zakharevich, provides on-demand loaded hashes.
942 C<Tie::RefHash::Nestable>, by Edward Avis, allows storing hash
943 references (unlike the standard Tie::RefHash) The module is contained
944 within Tie::RefHash, see L<Tie::RefHash>.
948 C<Time::HiRes> provides high resolution timing (ualarm, usleep,
949 and gettimeofday), from Douglas E. Wegscheid. See L<Time::HiRes>.
953 C<Unicode::UCD> offers a querying interface to the Unicode Character
954 Database. See L<Unicode::UCD>.
958 C<Unicode::Collate> implements the UCA (Unicode Collation Algorithm)
959 for sorting Unicode strings, by SADAHIRO Tomoyuki. See L<Unicode::Collate>.
963 C<Unicode::Normalize> implements the various Unicode normalization
964 forms, by SADAHIRO Tomoyuki. See L<Unicode::Normalize>.
968 C<XS::Typemap>, by Tim Jenness, is a test extension that exercises XS
969 typemaps. Nothing gets installed but for extension writers the code
974 =head2 Updated And Improved Modules and Pragmata
980 The following independently supported modules have been updated to the
981 newest versions from CPAN: CGI, CPAN, DB_File, File::Spec, File::Temp,
982 Getopt::Long, Math::BigFloat, Math::BigInt, the podlators bundle
983 (Pod::Man, Pod::Text), Pod::LaTeX, Pod::Parser, Storable,
984 Term::ANSIColor, Test, Text-Tabs+Wrap.
988 The attributes::reftype() now works on tied arguments.
992 AutoLoader can now be disabled with C<no AutoLoader;>.
996 B::Deparse has been significantly enhanced. It now can deparse almost
997 all of the standard test suite (so that the tests still succeed).
998 There is a make target "test.deparse" for trying this out.
1002 Class::Struct can now define the classes in compile time.
1006 Class::Struct now assigns the array/hash element if the accessor
1007 is called with an array/hash element as the B<sole> argument.
1011 Data::Dumper has now an option to sort hashes.
1015 Data::Dumper has now an option to dump code references
1020 DB_File now supports newer Berkeley DB versions, among
1025 The English module can now be used without the infamous performance
1028 use English '-no_match_vars';
1030 (Assuming, of course, that one doesn't need the troublesome variables
1031 C<$`>, C<$&>, or C<$'>.) Also, introduced C<@LAST_MATCH_START> and
1032 C<@LAST_MATCH_END> English aliases for C<@-> and C<@+>.
1036 Fcntl, Socket, and Sys::Syslog have been rewritten to use the
1037 new-style constant dispatch section (see L<ExtUtils::Constant>).
1038 This means that they will be more robust and hopefully faster.
1042 File::Find now chdir()s correctly when chasing symbolic links.
1046 File::Find now has pre- and post-processing callbacks. It also
1047 correctly changes directories when chasing symbolic links. Callbacks
1048 (naughtily) exiting with "next;" instead of "return;" now work.
1052 File::Find is now (again) reentrant. It also has been made
1057 The warnings issued by File::Find now belong to their own category.
1058 You can enable/disable them with C<use/no warnings 'File::Find';>.
1062 File::Glob::glob() renamed to File::Glob::bsd_glob() to avoid
1063 prototype mismatch with CORE::glob().
1067 File::Glob now supports C<GLOB_LIMIT> constant to limit the size of
1068 the returned list of filenames.
1072 Devel::Peek now has an interface for the Perl memory statistics
1073 (this works only if you are using perl's malloc, and if you have
1074 compiled with debugging).
1078 IPC::Open3 now allows the use of numeric file descriptors.
1082 IO::Socket has now atmark() method, which returns true if the socket
1083 is positioned at the out-of-band mark. The method is also exportable
1084 as a sockatmark() function.
1088 IO::Socket::INET has support for ReusePort option (if your platform
1089 supports it). The Reuse option now has an alias, ReuseAddr. For clarity
1090 you may want to prefer ReuseAddr.
1094 IO::Socket::INET now supports C<LocalPort> of zero (usually meaning
1095 that the operating system will make one up.)
1099 use lib now works identically to @INC. Removing directories
1100 with 'no lib' now works.
1104 ExtUtils::MakeMaker now uses File::Spec internally, which hopefully
1105 leads into better portability.
1109 Math::BigFloat and Math::BigInt have undergone a full rewrite.
1110 They are now magnitudes faster, and they support various
1111 bignum libraries such as GMP and PARI as their backends.
1115 Math::Complex handles inf, NaN etc., better.
1119 Net::Ping has been muchly enhanced: multihoming is now supported,
1120 Win32 functionality is better, there is now time measuring
1121 functionality (optionally high-resolution using Time::HiRes),
1122 and there is now "external" protocol which uses Net::Ping::External
1123 module which runs your external ping utility and parses the output.
1124 A version of Net::Ping::External is available in CPAN.
1126 Note that some of the Net::Ping tests are disabled when running
1127 under the Perl distribution since one cannot assume one or more
1128 of the following: enabled echo port at localhost, full Internet
1129 connectivity, or sympathetic firewalls. You can set the environment
1130 variable PERL_TEST_Net_Ping to "1" (one) before running the Perl test
1131 suite to enable all the Net::Ping tests.
1135 POSIX::sigaction() is now much more flexible and robust.
1136 You can now install coderef handlers, 'DEFAULT', and 'IGNORE'
1137 handlers, installing new handlers was not atomic.
1141 In Safe the C<%INC> now localised in a Safe compartment so that
1146 In SDBM_File on dosish platforms, some keys went missing because of
1147 lack of support for files with "holes". A workaround for the problem
1152 In Search::Dict one can now have a pre-processing hook for the
1153 lines being searched.
1157 The Shell module now has an OO interface.
1161 In Sys::Syslog there is now a failover mechanism that will go
1162 through alternative connection mechanisms until the message
1163 is successfully logged.
1167 The Test module has been significantly enhanced.
1171 Time::Local::timelocal() does not handle fractional seconds anymore.
1172 The rationale is that neither does localtime(), and timelocal() and
1173 localtime() are supposed to be inverses of each other.
1177 The vars pragma now supports declaring fully qualified variables.
1178 (Something that C<our()> does not and will not support.)
1182 The C<utf8::> name space (as in the pragma) provides various
1183 Perl-callable functions to provide low level access to Perl's
1184 internal Unicode representation. At the moment only length()
1185 has been implemented.
1189 =head1 Utility Changes
1195 Emacs perl mode (emacs/cperl-mode.el) has been updated to version
1200 F<emacs/e2ctags.pl> is now much faster.
1204 C<enc2xs> is a tool for people adding their own encodings to the
1209 C<h2ph> now supports C trigraphs.
1213 C<h2xs> now produces a template README.
1217 C<h2xs> now uses C<Devel::PPort> for better portability between
1218 different versions of Perl.
1222 C<h2xs> uses the new L<ExtUtils::Constant> module which will affect
1223 newly created extensions that define constants. Since the new code is
1224 more correct (if you have two constants where the first one is a
1225 prefix of the second one, the first constant B<never> gets defined),
1226 less lossy (it uses integers for integer constant, as opposed to the
1227 old code that used floating point numbers even for integer constants),
1228 and slightly faster, you might want to consider regenerating your
1229 extension code (the new scheme makes regenerating easy).
1230 L<h2xs> now also supports C trigraphs.
1234 C<libnetcfg> has been added to configure the libnet.
1238 C<perlbug> is now much more robust. It also sends the bug report to
1239 perl.org, not perl.com.
1243 C<perlcc> has been rewritten and its user interface (that is,
1244 command line) is much more like that of the UNIX C compiler, cc.
1245 (The perlbc tools has been removed. Use C<perlcc -B> instead.)
1249 C<perlivp> is a new Installation Verification Procedure utility
1250 for running any time after installing Perl.
1254 C<piconv> is an implementation of the character conversion utility
1255 C<iconv>, demonstrating the new Encode module.
1259 C<pod2html> now allows specifying a cache directory.
1263 C<s2p> has been completely rewritten in Perl. (It is in fact a full
1264 implementation of sed in Perl: you can use the sed functionality by
1265 using the C<psed> utility.)
1269 C<xsubpp> now understands POD documentation embedded in the *.xs files.
1273 C<xsubpp> now supports OUT keyword.
1277 =head1 New Documentation
1283 perl56delta details the changes between the 5.005 release and the
1288 perlclib documents the internal replacements for standard C library
1289 functions. (Interesting only for extension writers and Perl core
1294 perldebtut is a Perl debugging tutorial.
1298 perlebcdic contains considerations for running Perl on EBCDIC platforms.
1302 perlintro is a gentle introduction to Perl.
1306 perliol documents the internals of PerlIO with layers.
1310 perlmodstyle is a style guide for writing modules.
1314 perlnewmod tells about writing and submitting a new module.
1318 perlpacktut is a pack() tutorial.
1322 perlpod has been rewritten to be clearer and to record the best
1323 practices gathered over the years.
1327 perlpodspec is a more formal specification of the pod format,
1328 mainly of interest for writers of pod applications, not to
1329 people writing in pod.
1333 perlretut is a regular expression tutorial.
1337 perlrequick is a regular expressions quick-start guide.
1338 Yes, much quicker than perlretut.
1342 perltodo has been updated.
1346 perltootc has been renamed as perltooc (to not to conflict
1347 with perltoot in filesystems restricted to "8.3" names)
1351 perluniintro is an introduction to using Unicode in Perl.
1352 (perlunicode is more of a detailed reference and background
1357 perlutil explains the command line utilities packaged with the Perl
1362 The following platform-specific documents are available before
1363 the installation as README.I<platform>, and after the installation
1366 perlaix perlamiga perlapollo perlbeos perlbs2000
1367 perlce perlcygwin perldgux perldos perlepoc perlhpux
1368 perlhurd perlmachten perlmacos perlmint perlmpeix
1369 perlnetware perlos2 perlos390 perlplan9 perlqnx perlsolaris
1370 perltru64 perluts perlvmesa perlvms perlvos perlwin32
1376 The documentation for the POSIX-BC platform is called "BS2000", to avoid
1377 confusion with the Perl POSIX module.
1381 The documentation for the WinCE platform is called perlce (README.ce
1382 in the source code kit), to avoid confusion with the perlwin32
1383 documentation on 8.3-restricted filesystems.
1387 =head1 Performance Enhancements
1393 map() could get pathologically slow when the result list it generates
1394 is larger than the source list. The performance has been improved for
1399 sort() has been changed to use primarily mergesort internally as
1400 opposed to the earlier quicksort. For very small lists this may
1401 result in slightly slower sorting times, but in general the speedup
1402 should be at least 20%. Additional bonuses are that the worst case
1403 behaviour of sort() is now better (in computer science terms it now
1404 runs in time O(N log N), as opposed to quicksort's Theta(N**2)
1405 worst-case run time behaviour), and that sort() is now stable
1406 (meaning that elements with identical keys will stay ordered as they
1407 were before the sort). See the C<sort> pragma for information.
1409 The story in more detail: suppose you want to serve yourself a little
1412 @digits = ( 3,1,4,1,5,9 );
1414 A numerical sort of the digits will yield (1,1,3,4,5,9), as expected.
1415 Which C<1> comes first is hard to know, since one C<1> looks pretty
1416 much like any other. You can regard this as totally trivial,
1417 or somewhat profound. However, if you just want to sort the even
1418 digits ahead of the odd ones, then what will
1420 sort { ($a % 2) <=> ($b % 2) } @digits;
1422 yield? The only even digit, C<4>, will come first. But how about
1423 the odd numbers, which all compare equal? With the quicksort algorithm
1424 used to implement Perl 5.6 and earlier, the order of ties is left up
1425 to the sort. So, as you add more and more digits of Pi, the order
1426 in which the sorted even and odd digits appear will change.
1427 and, for sufficiently large slices of Pi, the quicksort algorithm
1428 in Perl 5.8 won't return the same results even if reinvoked with the
1429 same input. The justification for this rests with quicksort's
1430 worst case behavior. If you run
1432 sort { $a <=> $b } ( 1 .. $N , 1 .. $N );
1434 (something you might approximate if you wanted to merge two sorted
1435 arrays using sort), doubling $N doesn't just double the quicksort time,
1436 it I<quadruples> it. Quicksort has a worst case run time that can
1437 grow like N**2, so-called I<quadratic> behaviour, and it can happen
1438 on patterns that may well arise in normal use. You won't notice this
1439 for small arrays, but you I<will> notice it with larger arrays,
1440 and you may not live long enough for the sort to complete on arrays
1441 of a million elements. So the 5.8 quicksort scrambles large arrays
1442 before sorting them, as a statistical defence against quadratic behaviour.
1443 But that means if you sort the same large array twice, ties may be
1444 broken in different ways.
1446 Because of the unpredictability of tie-breaking order, and the quadratic
1447 worst-case behaviour, quicksort was I<almost> replaced completely with
1448 a stable mergesort. I<Stable> means that ties are broken to preserve
1449 the original order of appearance in the input array. So
1451 sort { ($a % 2) <=> ($b % 2) } (3,1,4,1,5,9);
1453 will yield (4,3,1,1,5,9), guaranteed. The even and odd numbers
1454 appear in the output in the same order they appeared in the input.
1455 Mergesort has worst case O(NlogN) behaviour, the best value
1456 attainable. And, ironically, this mergesort does particularly
1457 well where quicksort goes quadratic: mergesort sorts (1..$N, 1..$N)
1458 in O(N) time. But quicksort was rescued at the last moment because
1459 it is faster than mergesort on certain inputs and platforms.
1460 For example, if you really I<don't> care about the order of even
1461 and odd digits, quicksort will run in O(N) time; it's very good
1462 at sorting many repetitions of a small number of distinct elements.
1463 The quicksort divide and conquer strategy works well on platforms
1464 with relatively small, very fast, caches. Eventually, the problem gets
1465 whittled down to one that fits in the cache, from which point it
1466 benefits from the increased memory speed.
1468 Quicksort was rescued by implementing a sort pragma to control aspects
1469 of the sort. The B<stable> subpragma forces stable behaviour,
1470 regardless of algorithm. The B<_quicksort> and B<_mergesort>
1471 subpragmas are heavy-handed ways to select the underlying implementation.
1472 The leading C<_> is a reminder that these subpragmas may not survive
1473 beyond 5.8. More appropriate mechanisms for selecting the implementation
1474 exist, but they wouldn't have arrived in time to save quicksort.
1478 Hashes now use Bob Jenkins "One-at-a-Time" hashing key algorithm
1479 ( http://burtleburtle.net/bob/hash/doobs.html ). This algorithm is
1480 reasonably fast while producing a much better spread of values than
1481 the old hashing algorithm (originally by Chris Torek, later tweaked by
1482 Ilya Zakharevich). Hash values output from the algorithm on a hash of
1483 all 3-char printable ASCII keys comes much closer to passing the
1484 DIEHARD random number generation tests. According to perlbench, this
1485 change has not affected the overall speed of Perl.
1489 unshift() should now be noticeably faster.
1493 =head1 Installation and Configuration Improvements
1495 =head2 Generic Improvements
1501 INSTALL now explains how you can configure Perl to use 64-bit
1502 integers even on non-64-bit platforms.
1506 Policy.sh policy change: if you are reusing a Policy.sh file
1507 (see INSTALL) and you use Configure -Dprefix=/foo/bar and in the old
1508 Policy $prefix eq $siteprefix and $prefix eq $vendorprefix, all of
1509 them will now be changed to the new prefix, /foo/bar. (Previously
1510 only $prefix changed.) If you do not like this new behaviour,
1511 specify prefix, siteprefix, and vendorprefix explicitly.
1515 A new optional location for Perl libraries, otherlibdirs, is available.
1516 It can be used for example for vendor add-ons without disturbing Perl's
1517 own library directories.
1521 In many platforms the vendor-supplied 'cc' is too stripped-down to
1522 build Perl (basically, 'cc' doesn't do ANSI C). If this seems
1523 to be the case and 'cc' does not seem to be the GNU C compiler
1524 'gcc', an automatic attempt is made to find and use 'gcc' instead.
1528 gcc needs to closely track the operating system release to avoid
1529 build problems. If Configure finds that gcc was built for a different
1530 operating system release than is running, it now gives a clearly visible
1531 warning that there may be trouble ahead.
1535 If binary compatibility with the 5.005 release is not wanted, Configure
1536 no longer suggests including the 5.005 modules in @INC.
1540 Configure C<-S> can now run non-interactively.
1544 Configure support for pdp11-style memory models has been removed due
1549 configure.gnu now works with options with whitespace in them.
1553 installperl now outputs everything to STDERR.
1557 $Config{byteorder} is now computed dynamically (this is more robust
1558 with "fat binaries" where an executable image contains binaries for
1559 more than one binary platform.)
1563 Because PerlIO is now the default on most platforms, "-perlio" doesn't
1564 get appended to the $Config{archname} (also known as $^O) anymore.
1565 Instead, if you explicitly choose not to use perlio (Configure command
1566 line option -Uuseperlio), you will get "-stdio" appended.
1570 Another change related to the architecture name is that "-64all"
1571 (-Duse64bitall, or "maximally 64-bit") is appended only if your
1572 pointers are 64 bits wide. (To be exact, the use64bitall is ignored.)
1576 In AFS installations one can configure the root of the AFS to be
1577 somewhere else than the default F</afs> by using the Configure
1578 parameter C<-Dafsroot=/some/where/else>.
1582 APPLLIB_EXP, a less-know configuration-time definition, has been
1583 documented. It can be used to prepend site-specific directories
1584 to Perl's default search path (@INC), see INSTALL for information.
1588 The version of Berkeley DB used when the Perl (and, presumably, the
1589 DB_File extension) was built is now available as
1590 C<@Config{qw(db_version_major db_version_minor db_version_patch)}>
1591 from Perl and as C<DB_VERSION_MAJOR_CFG DB_VERSION_MINOR_CFG
1592 DB_VERSION_PATCH_CFG> from C.
1596 Building Berkeley DB3 for compatibility modes for DB, NDBM, and ODBM
1597 has been documented in INSTALL.
1601 If you have CPAN access (either network or a local copy such as a
1602 CD-ROM) you can during specify extra modules to Configure to build and
1603 install with Perl using the -Dextras=... option. See INSTALL for
1608 In addition to config.over a new override file, config.arch, is
1609 available. That is supposed to be used by hints file writers for
1610 architecture-wide changes (as opposed to config.over which is for
1615 If your file system supports symbolic links you can build Perl outside
1616 of the source directory by
1618 mkdir /tmp/perl/build/directory
1619 cd /tmp/perl/build/directory
1620 sh /path/to/perl/source/Configure -Dmksymlinks ...
1622 This will create in /tmp/perl/build/directory a tree of symbolic links
1623 pointing to files in /path/to/perl/source. The original files are left
1624 unaffected. After Configure has finished you can just say
1628 and Perl will be built and tested, all in /tmp/perl/build/directory.
1632 For Perl developers several new make targets for profiling
1633 and debugging have been added, see L<perlhack>.
1639 Use of the F<gprof> tool to profile Perl has been documented in
1640 L<perlhack>. There is a make target called "perl.gprof" for
1641 generating a gprofiled Perl executable.
1645 If you have GCC 3, there is a make target called "perl.gcov" for
1646 creating a gcoved Perl executable for coverage analysis. See
1651 If you are on IRIX or Tru64 platforms, new profiling/debugging options
1652 have been added, see L<perlhack> for more information about pixie and
1659 Guidelines of how to construct minimal Perl installations have
1660 been added to INSTALL.
1664 The Thread extension is now not built at all under ithreads
1665 (C<Configure -Duseithreads>) because it wouldn't work anyway (the
1666 Thread extension requires being Configured with C<-Duse5005threads>).
1668 But note that the Thread.pm interface is now shared by both
1673 The Gconvert macro ($Config{d_Gconvert}) used by perl for stringifying
1674 floating-point numbers is now more picky about using sprintf %.*g
1675 rules for the conversion. Some platforms that used to use gcvt may
1676 now resort to the slower sprintf.
1680 =head2 New Or Improved Platforms
1682 For the list of platforms known to support Perl,
1683 see L<perlport/"Supported Platforms">.
1689 AIX dynamic loading should be now better supported.
1693 AIX should now work better with gcc, threads, and 64-bitness. Also the
1694 long doubles support in AIX should be better now. See L<perlaix>.
1698 After a long pause, AmigaOS has been verified to be happy with Perl.
1702 AtheOS ( http://www.atheos.cx/ ) is a new platform.
1706 BeOS has been reclaimed.
1710 DG/UX platform now supports the 5.005-style threads. See L<perldgux>.
1714 DYNIX/ptx platform (a.k.a. dynixptx) is supported at or near osvers 4.5.2.
1718 EBCDIC platforms (z/OS, also known as OS/390, POSIX-BC, and VM/ESA)
1719 have been regained. Many test suite tests still fail and the
1720 co-existence of Unicode and EBCDIC isn't quite settled, but the
1721 situation is much better than with Perl 5.6. See L<perlos390>,
1722 L<perlbs2000> (for POSIX-BC), and L<perlvmesa> for more information.
1726 Building perl with -Duseithreads or -Duse5005threads now works under
1727 HP-UX 10.20 (previously it only worked under 10.30 or later). You will
1728 need a thread library package installed. See README.hpux.
1732 MacOS Classic (MacPerl has of course been available since
1733 perl 5.004 but now the source code bases of standard Perl
1734 and MacPerl have been synchronised)
1738 MacOS X (or Darwin) should now be able to build Perl even on HFS+
1739 filesystems. (The case-insensitivity confused the Perl build process.)
1743 NCR MP-RAS is now supported.
1747 All the NetBSD specific patches (except for the installation
1748 specific ones) have been merged back to the main distribution.
1752 NetWare from Novell is now supported. See L<perlnetware>.
1756 NonStop-UX is now supported.
1760 NEC SUPER-UX is now supported.
1764 All the OpenBSD specific patches (except for the installation
1765 specific ones) have been merged back to the main distribution.
1769 Perl has been tested with the GNU pth userlevel thread package
1770 ( http://www.gnu.org/software/pth/pth.html ) . All but one thread
1771 test worked, and that one failure was because of test results arriving
1772 in unexpected order.
1776 Amdahl UTS UNIX mainframe platform is now supported.
1780 WinCE is now supported. See L<perlce>.
1784 z/OS (formerly known as OS/390, formerly known as MVS OE) has now
1785 support for dynamic loading. This is not selected by default,
1786 however, you must specify -Dusedl in the arguments of Configure.
1790 =head1 Selected Bug Fixes
1792 Numerous memory leaks and uninitialized memory accesses have been
1793 hunted down. Most importantly anonymous subs used to leak quite
1800 The autouse pragma didn't work for Multi::Part::Function::Names.
1804 caller() could cause core dumps in certain situations. Carp was sometimes
1805 affected by this problem.
1809 chop(@list) in list context returned the characters chopped in
1810 reverse order. This has been reversed to be in the right order.
1814 Configure no longer includes the DBM libraries (dbm, gdbm, db, ndbm)
1815 when building the Perl binary. The only exception to this is SunOS 4.x,
1820 The behaviour of non-decimal but numeric string constants such as
1821 "0x23" was platform-dependent: in some platforms that was seen as 35,
1822 in some as 0, in some as a floating point number (don't ask). This
1823 was caused by Perl using the operating system libraries in a situation
1824 where the result of the string to number conversion is undefined: now
1825 Perl consistently handles such strings as zero in numeric contexts.
1829 The order of DESTROYs has been made more predictable.
1833 Several debugger fixes: exit code now reflects the script exit code,
1834 condition C<"0"> now treated correctly, the C<d> command now checks
1835 line number, the C<$.> no longer gets corrupted, all debugger output
1836 now goes correctly to the socket if RemotePort is set.
1840 Perl 5.6.0 could emit spurious warnings about redefinition of dl_error()
1841 when statically building extensions into perl. This has been corrected.
1845 L<dprofpp> -R didn't work.
1849 C<*foo{FORMAT}> now works.
1852 Infinity is now recognized as a number.
1856 UNIVERSAL::isa no longer caches methods incorrectly. (This broke
1857 the Tk extension with 5.6.0.)
1861 Lexicals I: lexicals outside an eval "" weren't resolved
1862 correctly inside a subroutine definition inside the eval "" if they
1863 were not already referenced in the top level of the eval""ed code.
1867 Lexicals II: lexicals leaked at file scope into subroutines that
1868 were declared before the lexicals.
1872 Lexical warnings now propagating correctly between scopes
1873 and into C<eval "...">.
1877 C<use warnings qw(FATAL all)> did not work as intended. This has been
1882 warnings::enabled() now reports the state of $^W correctly if the caller
1883 isn't using lexical warnings.
1887 Line renumbering with eval and C<#line> now works.
1891 Fixed numerous memory leaks, especially in eval "".
1895 mkdir() now ignores trailing slashes in the directory name,
1896 as mandated by POSIX.
1900 Some versions of glibc have a broken modfl(). This affects builds
1901 with C<-Duselongdouble>. This version of Perl detects this brokenness
1902 and has a workaround for it. The glibc release 2.2.2 is known to have
1903 fixed the modfl() bug.
1907 Modulus of unsigned numbers now works (4063328477 % 65535 used to
1908 return 27406, instead of 27047).
1912 Some "not a number" warnings introduced in 5.6.0 eliminated to be
1913 more compatible with 5.005. Infinity is now recognised as a number.
1917 Numeric conversions did not recognize changes in the string value
1918 properly in certain circumstances.
1922 Attributes (like :shared) didn't work with our().
1926 our() variables will not cause "will not stay shared" warnings.
1930 "our" variables of the same name declared in two sibling blocks
1931 resulted in bogus warnings about "redeclaration" of the variables.
1932 The problem has been corrected.
1936 pack "Z" now correctly terminates the string with "\0".
1940 Fix password routines which in some shadow password platforms
1941 (e.g. HP-UX) caused getpwent() to return every other entry.
1945 The PERL5OPT environment variable (for passing command line arguments
1946 to Perl) didn't work for more than a single group of options.
1950 PERL5OPT with embedded spaces didn't work.
1954 printf() no longer resets the numeric locale to "C".
1958 C<qw(a\\b)> now parses correctly as C<'a\\b'>.
1962 pos() did not return the correct value within s///ge in earlier
1963 versions. This is now handled correctly.
1967 Printing quads (64-bit integers) with printf/sprintf now works
1968 without the q L ll prefixes (assuming you are on a quad-capable platform).
1972 Regular expressions on references and overloaded scalars now work.
1976 Right-hand side magic (GMAGIC) could in many cases such as string
1977 concatenation be invoked too many times.
1981 scalar() now forces scalar context even when used in void context.
1985 SOCKS support is now much more robust.
1989 sort() arguments are now compiled in the right wantarray context
1990 (they were accidentally using the context of the sort() itself).
1991 The comparison block is now run in scalar context, and the arguments
1992 to be sorted are always provided list context.
1996 Changed the POSIX character class C<[[:space:]]> to include the (very
1997 rarely used) vertical tab character. Added a new POSIX-ish character
1998 class C<[[:blank:]]> which stands for horizontal whitespace
1999 (currently, the space and the tab).
2003 The tainting behaviour of sprintf() has been rationalized. It does
2004 not taint the result of floating point formats anymore, making the
2005 behaviour consistent with that of string interpolation.
2009 Some cases of inconsistent taint propagation (such as within hash
2010 values) have been fixed.
2014 The RE engine found in Perl 5.6.0 accidentally pessimised certain kinds
2015 of simple pattern matches. These are now handled better.
2019 Regular expression debug output (whether through C<use re 'debug'>
2020 or via C<-Dr>) now looks better.
2024 Multi-line matches like C<"a\nxb\n" =~ /(?!\A)x/m> were flawed. The
2029 Use of $& could trigger a core dump under some situations. This
2034 The regular expression captured submatches ($1, $2, ...) are now
2035 more consistently unset if the match fails, instead of leaving false
2036 data lying around in them.
2040 readline() on files opened in "slurp" mode could return an extra "" at
2041 the end in certain situations. This has been corrected.
2045 Autovivification of symbolic references of special variables described
2046 in L<perlvar> (as in C<${$num}>) was accidentally disabled. This works
2051 Sys::Syslog ignored the C<LOG_AUTH> constant.
2055 All but the first argument of the IO syswrite() method are now optional.
2059 $AUTOLOAD, sort(), lock(), and spawning subprocesses
2060 in multiple threads simultaneously are now thread-safe.
2064 Tie::ARRAY SPLICE method was broken.
2068 Allow read-only string on left hand side of non-modifying tr///.
2072 If C<STDERR> is tied, warnings caused by C<warn> and C<die> now
2073 correctly pass to it.
2077 Several Unicode fixes.
2083 BOMs (byte order marks) in the beginning of Perl files
2084 (scripts, modules) should now be transparently skipped.
2085 UTF-16 (UCS-2) encoded Perl files should now be read correctly.
2089 The character tables have been updated to Unicode 3.1.1.
2093 Comparing with utf8 data does not magically upgrade non-utf8 data
2094 into utf8. (This was a problem for example if you were mixing data
2095 from I/O and Unicode data: your output might have got magically encoded
2100 Generating illegal Unicode code points like U+FFFE, or the UTF-16
2101 surrogates, now also generates an optional warning.
2105 C<IsAlnum>, C<IsAlpha>, and C<IsWord> now match titlecase.
2109 Concatenation with the C<.> operator or via variable interpolation,
2110 C<eq>, C<substr>, C<reverse>, C<quotemeta>, the C<x> operator,
2111 substitution with C<s///>, single-quoted UTF8, should now work.
2115 The C<tr///> operator now works. Note that the C<tr///CU>
2116 functionality has been removed (but see pack('U0', ...)).
2120 C<eval "v200"> now works.
2124 Perl 5.6.0 parsed m/\x{ab}/ incorrectly, leading to spurious warnings.
2125 This has been corrected.
2129 Zero entries were missing from the Unicode classes like C<IsDigit>.
2135 Large unsigned numbers (those above 2**31) could sometimes lose their
2136 unsignedness, causing bogus results in arithmetic operations.
2140 =head2 Platform Specific Changes and Fixes
2148 Perl now works on post-4.0 BSD/OSes.
2154 Setting C<$0> now works (as much as possible; see L<perlvar> for details).
2160 Numerous updates; currently synchronised with Cygwin 1.3.10.
2164 Previously DYNIX/ptx had problems in its Configure probe for non-blocking I/O.
2170 EPOC update after Perl 5.6.0. See README.epoc.
2176 Perl now works on post-3.0 FreeBSDs.
2182 README.hpux updated; C<Configure -Duse64bitall> now works.
2188 Numerous compilation flag and hint enhancements; accidental mixing
2189 of 32-bit and 64-bit libraries (a doomed attempt) made much harder.
2199 Long doubles should now work (see INSTALL).
2203 Linux previously had problems related to sockaddrlen when using
2204 accept(), revcfrom() (in Perl: recv()), getpeername(), and getsockname().
2212 Compilation of the standard Perl distribution in MacOS Classic should
2213 now work if you have the Metrowerks development environment and
2214 the missing Mac-specific toolkit bits. Contact the macperl mailing
2221 MPE/iX update after Perl 5.6.0. See README.mpeix.
2227 Perl now works on NetBSD/sparc.
2233 Now works with usethreads (see INSTALL).
2239 64-bitness using the Sun Workshop compiler now works.
2243 Tru64 (aka Digital UNIX, aka DEC OSF/1)
2245 The operating system version letter now recorded in $Config{osvers}.
2246 Allow compiling with gcc (previously explicitly forbidden). Compiling
2247 with gcc still not recommended because buggy code results, even with
2254 Fixed various alignment problems that lead into core dumps either
2255 during build or later; no longer dies on math errors at runtime;
2256 now using full quad integers (64 bits), previously was using
2257 only 46 bit integers for speed.
2263 chdir() now works better despite a CRT bug; now works with MULTIPLICITY
2264 (see INSTALL); now works with Perl's malloc.
2266 The tainting of C<%ENV> elements via C<keys> or C<values> was previously
2267 unimplemented. It now works as documented.
2269 The C<waitpid> emulation has been improved. The worst bug (now fixed)
2270 was that a pid of -1 would cause a wildcard search of all processes on
2271 the system. The most significant enhancement is that we can now
2272 usually get the completion status of a terminated process.
2274 POSIX-style signals are now emulated much better on VMS versions prior
2277 The C<system> function and backticks operator have improved
2278 functionality and better error handling.
2280 File access tests now use current process privileges rather than the
2281 user's default privileges, which could sometimes result in a mismatch
2282 between reported access and actual access.
2292 accept() no longer leaks memory.
2296 Borland C++ v5.5 is now a supported compiler that can build Perl.
2297 However, the generated binaries continue to be incompatible with those
2298 generated by the other supported compilers (GCC and Visual C++).
2302 Better chdir() return value for a non-existent directory.
2306 Duping socket handles with open(F, ">&MYSOCK") now works under Windows 9x.
2310 New %ENV entries now propagate to subprocesses.
2314 Current directory entries in %ENV are now correctly propagated to child
2319 $ENV{LIB} now used to search for libs under Visual C.
2323 fork() emulation has been improved in various ways, but still continues
2324 to be experimental. See L<perlfork> for known bugs and caveats.
2328 A failed (pseudo)fork now returns undef and sets errno to EAGAIN.
2332 Win32::GetCwd() correctly returns C:\ instead of C: when at the drive root.
2333 Other bugs in chdir() and Cwd::cwd() have also been fixed.
2337 HTML files will be installed in c:\perl\html instead of c:\perl\lib\pod\html
2341 The makefiles now provide a single switch to bulk-enable all the features
2342 enabled in ActiveState ActivePerl (a popular Win32 binary distribution).
2346 Allow REG_EXPAND_SZ keys in the registry.
2350 Can now send() from all threads, not just the first one.
2354 Fake signal handling reenabled, bugs and all.
2358 %SIG has been enabled under USE_ITHREADS, but its use is completely
2359 unsupported under all configurations.
2363 Less stack reserved per thread so that more threads can run
2364 concurrently. (Still 16M per thread.)
2368 C<File::Spec->tmpdir()> now prefers C:/temp over /tmp
2369 (works better when perl is running as service).
2373 Better UNC path handling under ithreads.
2377 wait(), waitpid() and backticks now return the correct exit status under
2382 winsock handle leak fixed.
2386 The Perl parser has been stress tested using both random input and
2387 Markov chain input and the few found crashes and lockups have been
2394 =head1 New or Changed Diagnostics
2400 The lexical warnings category "deprecated" is no longer a sub-category
2401 of the "syntax" category. It is now a top-level category in its own
2406 All regular expression compilation error messages are now hopefully
2407 easier to understand both because the error message now comes before
2408 the failed regex and because the point of failure is now clearly
2409 marked by a C<E<lt>-- HERE> marker.
2413 The various "opened only for", "on closed", "never opened" warnings
2414 drop the C<main::> prefix for filehandles in the C<main> package,
2415 for example C<STDIN> instead of C<main::STDIN>.
2419 The "Unrecognized escape" warning has been extended to include C<\8>,
2420 C<\9>, and C<\_>. There is no need to escape any of the C<\w> characters.
2424 Two new debugging options have been added: if you have compiled your
2425 Perl with debugging, you can use the -DT and -DR options to trace
2426 tokenising and to add reference counts to displaying variables,
2431 The debugger (perl5db.pl) has been modified to present a more
2432 consistent commands interface, via (CommandSet=580). perl5db.t was
2433 also added to test the changes, and as a placeholder for further tests.
2439 The debugger has a new C<dumpDepth> option to control the maximum
2440 depth to which nested structures are dumped. The C<x> command has
2441 been extended so that C<x N EXPR> dumps out the value of I<EXPR> to a
2442 depth of at most I<N> levels.
2446 The debugger can now show lexical variables if you have the CPAN
2447 module PadWalker installed.
2451 If an attempt to use a (non-blessed) reference as an array index
2452 is made, a warning is given.
2456 C<push @a;> and C<unshift @a;> (with no values to push or unshift)
2457 now give a warning. This may be a problem for generated and evaled
2462 If you try to L<perlfunc/pack> a number less than 0 or larger than 255
2463 using the C<"C"> format you will get an optional warning. Similarly
2464 for the C<"c"> format and a number less than -128 or more than 127.
2468 Certain regex modifiers such as C<(?o)> make sense only if applied to
2469 the entire regex. You will get an optional warning if you try to do
2474 Using arrays or hashes as references (e.g. C<< %foo->{bar} >>
2475 has been deprecated for a while. Now you will get an optional warning.
2479 Using C<sort> in scalar context now issues an optional warning.
2480 This didn't do anything useful, as the sort was not performed.
2484 =head1 Changed Internals
2490 perlapi.pod (a companion to perlguts) now attempts to document the
2495 You can now build a really minimal perl called microperl.
2496 Building microperl does not require even running Configure;
2497 C<make -f Makefile.micro> should be enough. Beware: microperl makes
2498 many assumptions, some of which may be too bold; the resulting
2499 executable may crash or otherwise misbehave in wondrous ways.
2500 For careful hackers only.
2504 Added rsignal(), whichsig(), do_join(), op_clear, op_null,
2505 ptr_table_clear(), ptr_table_free(), sv_setref_uv(), and several UTF-8
2506 interfaces to the publicised API. For the full list of the available
2507 APIs see L<perlapi>.
2511 Made possible to propagate customised exceptions via croak()ing.
2515 Now xsubs can have attributes just like subs. (Well, at least the
2516 built-in attributes.)
2520 dTHR and djSP have been obsoleted; the former removed (because it's
2521 a no-op) and the latter replaced with dSP.
2525 PERL_OBJECT has been completely removed.
2529 The MAGIC constants (e.g. C<'P'>) have been macrofied
2530 (e.g. C<PERL_MAGIC_TIED>) for better source code readability
2531 and maintainability.
2535 The regex compiler now maintains a structure that identifies nodes in
2536 the compiled bytecode with the corresponding syntactic features of the
2537 original regex expression. The information is attached to the new
2538 C<offsets> member of the C<struct regexp>. See L<perldebguts> for more
2539 complete information.
2543 The C code has been made much more C<gcc -Wall> clean. Some warning
2544 messages still remain in some platforms, so if you are compiling with
2545 gcc you may see some warnings about dubious practices. The warnings
2546 are being worked on.
2550 F<perly.c>, F<sv.c>, and F<sv.h> have now been extensively commented.
2554 Documentation on how to use the Perl source repository has been added
2555 to F<Porting/repository.pod>.
2559 There are now several profiling make targets.
2563 =head1 Security Vulnerability Closed
2565 (This change was already made in 5.7.0 but bears repeating here.)
2567 A potential security vulnerability in the optional suidperl component
2568 of Perl was identified in August 2000. suidperl is neither built nor
2569 installed by default. As of November 2001 the only known vulnerable
2570 platform is Linux, most likely all Linux distributions. CERT and
2571 various vendors and distributors have been alerted about the vulnerability.
2572 See http://www.cpan.org/src/5.0/sperl-2000-08-05/sperl-2000-08-05.txt
2573 for more information.
2575 The problem was caused by Perl trying to report a suspected security
2576 exploit attempt using an external program, /bin/mail. On Linux
2577 platforms the /bin/mail program had an undocumented feature which
2578 when combined with suidperl gave access to a root shell, resulting in
2579 a serious compromise instead of reporting the exploit attempt. If you
2580 don't have /bin/mail, or if you have 'safe setuid scripts', or if
2581 suidperl is not installed, you are safe.
2583 The exploit attempt reporting feature has been completely removed from
2584 Perl 5.8.0 (and the maintenance release 5.6.1, and it was removed also
2585 from all the Perl 5.7 releases), so that particular vulnerability
2586 isn't there anymore. However, further security vulnerabilities are,
2587 unfortunately, always possible. The suidperl functionality is most
2588 probably going to be removed in Perl 5.10. In any case, suidperl
2589 should only be used by security experts who know exactly what they are
2590 doing and why they are using suidperl instead of some other solution
2591 such as sudo ( see http://www.courtesan.com/sudo/ ).
2595 Several new tests have been added, especially for the F<lib>
2596 subsection. There are now about 56 000 individual tests (spread over
2597 about 620 test scripts), in the regression suite (5.6.1 has about
2598 11700 tests, in 258 test scripts) Many of the new tests are introduced
2599 by the new modules, but still in general Perl is now more thoroughly
2602 Because of the large number of tests, running the regression suite
2603 will take considerably longer time than it used to: expect the suite
2604 to take up to 4-5 times longer to run than in perl 5.6. In a really
2605 fast machine you can hope to finish the suite in about 6-8 minutes
2608 The tests are now reported in a different order than in earlier Perls.
2609 (This happens because the test scripts from under t/lib have been moved
2610 to be closer to the library/extension they are testing.)
2612 =head1 Known Problems
2620 In AIX 4.2 Perl extensions that use C++ functions that use statics
2621 may have problems in that the statics are not getting initialized.
2622 In newer AIX releases this has been solved by linking Perl with
2623 the libC_r library, but unfortunately in AIX 4.2 the said library
2624 has an obscure bug where the various functions related to time
2625 (such as time() and gettimeofday()) return broken values, and
2626 therefore in AIX 4.2 Perl is not linked against the libC_r.
2630 vac 5.0.0.0 May Produce Buggy Code For Perl
2632 The AIX C compiler vac version 5.0.0.0 may produce buggy code,
2633 resulting in few random tests failing, but when the failing tests
2634 are run by hand, they succeed. We suggest upgrading to at least
2635 vac version 5.0.1.0, that has been known to compile Perl correctly.
2636 "lslpp -L|grep vac.C" will tell you the vac version. See README.aix.
2640 If building threaded Perl, you may get compilation warning from pp_sys.c:
2642 "pp_sys.c", line 4651.39: 1506-280 (W) Function argument assignment between types "unsigned char*" and "const void*" is not allowed.
2644 This is harmless; it is caused by the getnetbyaddr() and getnetbyaddr_r()
2645 having slightly different types for their first argument.
2649 =head2 Amiga Perl Invoking Mystery
2651 One cannot call Perl using the C<volume:> syntax, that is, C<perl -v>
2652 works, but for example C<bin:perl -v> doesn't. The exact reason isn't
2653 known but the current suspect is the F<ixemul> library.
2655 =head2 FreeBSD Failing locale Test 117 For ISO8859-15 Locales
2657 The ISO8859-15 locales may fail the locale test 117 in FreeBSD.
2658 This is caused by the characters \xFF (y with diaeresis) and \xBE
2659 (Y with diaeresis) not behaving correctly when being matched
2662 =head2 mod_perl 1.26 Doesn't Build With Threaded Perl
2664 Use mod_perl 1.27 or higher.
2666 =head2 lib/ftmp-security tests warn 'system possibly insecure'
2668 Don't panic. Read INSTALL 'make test' section instead.
2670 =head2 HP-UX lib/posix Subtest 9 Fails When LP64-Configured
2672 If perl is configured with -Duse64bitall, the successful result of the
2673 subtest 10 of lib/posix may arrive before the successful result of the
2674 subtest 9, which confuses the test harness so much that it thinks the
2677 =head2 Linux With Sfio Fails op/misc Test 48
2683 Please remember to set your environment variable LC_ALL to "C"
2684 (setenv LC_ALL C) before running "make test" to avoid a lot of
2685 warnings about the broken locales of Mac OS X.
2687 The following tests are known to fail:
2689 Failed Test Stat Wstat Total Fail Failed List of Failed
2690 -------------------------------------------------------------------------
2691 ../ext/DB_File/t/db-btree.t 0 11 ?? ?? % ??
2692 ../ext/DB_File/t/db-recno.t 149 3 2.01% 61 63 65
2693 ../ext/POSIX/t/posix.t 31 1 3.23% 10
2695 If you are building on a UFS partition, you will also probably see
2696 t/op/stat.t subtest #9 fail. This is caused by Darwin's UFS not
2697 supporting inode change time.
2699 =head2 op/sprintf tests 91, 129, and 130
2701 The op/sprintf tests 91, 129, and 130 are known to fail on some platforms.
2702 Examples include any platform using sfio, and Compaq/Tandem's NonStop-UX.
2704 The test 91 is known to fail at QNX6 (nto), because C<sprintf '%e',0>
2705 incorrectly produces C<0.000000e+0> instead of C<0.000000e+00>.
2707 For the tests 129 and 130 the failing platforms do not comply with
2708 the ANSI C Standard, line 19ff on page 134 of ANSI X3.159 1989 to
2709 be exact. (They produce something other than "1" and "-1" when
2710 formatting 0.6 and -0.6 using the printf format "%.0f", most often
2711 they produce "0" and "-0".)
2713 =head2 Failure of Thread (5.005-style) tests
2715 B<Note that support for 5.005-style threading remains experimental
2716 and practically unsupported.>
2718 The following tests are known to fail due to fundamental problems in
2719 the 5.005 threading implementation. These are not new failures--Perl
2720 5.005_0x has the same bugs, but didn't have these tests.
2722 ../ext/List/Util/t/first.t 255 65280 7 4 57.14% 2 5-7
2723 ../lib/English.t 2 512 54 2 3.70% 2-3
2724 ../lib/Filter/Simple/t/data.t 6 3 50.00% 1-3
2725 ../lib/Filter/Simple/t/filter_onl 9 3 33.33% 1-2 5
2726 ../lib/autouse.t 10 1 10.00% 4
2727 op/flip.t 15 1 6.67% 15
2729 These failures are unlikely to get fixed as the 5.005-style
2730 threads are considered fundamentally broken.
2734 Failed Test Stat Wstat Total Fail Failed List of Failed
2735 -------------------------------------------------------------------------
2736 ../ext/Socket/socketpair.t 1 256 45 1 2.22% 12
2737 ../lib/Math/Trig.t 26 1 3.85% 25
2738 ../lib/warnings.t 460 1 0.22% 425
2739 io/fs.t 36 1 2.78% 31
2740 op/numconvert.t 1440 13 0.90% 208 509-510
2741 657-658 665-666 829-830 989-990 1149-1150
2743 =head2 UNICOS and UNICOS/mk
2745 The io/fs test #31 is failing because in UNICOS and UNICOS/mk the Perl
2746 truncate() cannot be used to grow the size of filehandles, only to
2747 reduce the size. The workaround is to truncate files instead of
2756 During Configure the test
2758 Guessing which symbols your C compiler and preprocessor define...
2760 will probably fail with error messages like
2762 CC-20 cc: ERROR File = try.c, Line = 3
2763 The identifier "bad" is undefined.
2765 bad switch yylook 79bad switch yylook 79bad switch yylook 79bad switch yylook 79#ifdef A29K
2768 CC-65 cc: ERROR File = try.c, Line = 3
2769 A semicolon is expected at this point.
2771 This is caused by a bug in awk utility of UNICOS/mk. You can ignore
2772 the error, but it does cause a slight problem: you cannot fully
2773 benefit from the h2ph utility (see L<h2ph>) that can be used to
2774 convert C headers to Perl libraries, mainly used to be able to access
2775 from Perl the constants defined using C preprocessor, cpp. Because of
2776 the above error parts of the converted headers will be invisible.
2777 Luckily, these days the need for h2ph is rare.
2781 If building Perl with the interpreter threads (ithreads), the
2782 getgrent(), getgrnam(), and getgrgid() functions cannot return the
2783 list of the group members due to a bug in the multithreaded support of
2784 UNICOS/mk. What this means that in list context the functions will
2785 return only three values, not four.
2791 There are a few known test failures, see L<perluts>.
2795 There should be no reported test failures with a default configuration,
2796 though there are a number of tests marked TODO that point to areas
2797 needing further debugging and/or porting work.
2801 In multi-CPU boxes there are some problems with the I/O buffering:
2802 some output may appear twice. The following Win32 failures are known
2805 Failed Test Stat Wstat Total Fail Failed List of Failed
2806 -------------------------------------------------------------------------
2807 ..\ext/threads/t/end.t 6 4 66.67% 3-6
2809 =head2 XML::Parser not working
2811 Use XML::Parser 2.31 or later.
2813 =head2 Localising a Tied Variable Leaks Memory
2816 tie my %tie_hash => 'Tie::StdHash';
2820 local($tie_hash{Foo}) = 1; # leaks
2822 Code like the above is known to leak memory every time the local()
2825 =head2 z/OS (OS/390)
2827 z/OS has rather many test failures but the situation is actually
2828 better than it was in 5.6.0, it's just that so many new modules and
2829 tests have been added.
2831 Failed Test Stat Wstat Total Fail Failed List of Failed
2832 -------------------------------------------------------------------------
2833 ../ext/Data/Dumper/t/dumper.t 321 2 0.62% 311 314
2834 ../ext/IO/lib/IO/t/io_unix.t 5 4 80.00% 2-5
2835 ../lib/utf8.t 94 13 13.83% 27 30-31 43 46 73
2838 ../lib/Benchmark.t 1 256 159 1 0.63% 75
2839 ../lib/ExtUtils/t/Constant.t 27 19 70.37% 5-23
2840 ../lib/ExtUtils/t/Embed.t 9 9 100.00% 1-9
2841 op/pat.t 864 9 1.04% 242-243 665 776
2843 op/sprintf.t 224 3 1.34% 98 100 136
2844 op/tr.t 97 5 5.15% 63 71-74
2845 uni/fold.t 780 6 0.77% 61 169 196 661
2848 =head2 Localising Tied Arrays and Hashes Is Broken
2852 doesn't work as one would expect: the old value is restored
2855 =head2 Self-tying of Arrays and Hashes Is Forbidden
2857 Self-tying of arrays and hashes is broken in rather deep and
2858 hard-to-fix ways. As a stop-gap measure to avoid people from getting
2859 frustrated at the mysterious results (core dumps, most often) it is
2860 for now forbidden (you will get a fatal error even from an attempt).
2862 =head2 Building Extensions Can Fail Because Of Largefiles
2864 Some extensions like mod_perl are known to have issues with
2865 `largefiles', a change brought by Perl 5.6.0 in which file offsets
2866 default to 64 bits wide, where supported. Modules may fail to compile
2867 at all or compile and work incorrectly. Currently there is no good
2868 solution for the problem, but Configure now provides appropriate
2869 non-largefile ccflags, ldflags, libswanted, and libs in the %Config
2870 hash (e.g., $Config{ccflags_nolargefiles}) so the extensions that are
2871 having problems can try configuring themselves without the
2872 largefileness. This is admittedly not a clean solution, and the
2873 solution may not even work at all. One potential failure is whether
2874 one can (or, if one can, whether it's a good idea) link together at
2875 all binaries with different ideas about file offsets, all this is
2878 =head2 Unicode Support on EBCDIC Still Spotty
2880 Though mostly working, Unicode support still has problem spots on
2881 EBCDIC platforms. One such known spot are the C<\p{}> and C<\P{}>
2882 regular expression constructs for code points less than 256: the
2883 pP are testing for Unicode code points, not knowing about EBCDIC.
2885 =head2 The Compiler Suite Is Still Experimental
2887 The compiler suite is slowly getting better but it continues to be
2888 highly experimental. Use in production environments is discouraged.
2890 =head2 The Long Double Support Is Still Experimental
2892 The ability to configure Perl's numbers to use "long doubles",
2893 floating point numbers of hopefully better accuracy, is still
2894 experimental. The implementations of long doubles are not yet
2895 widespread and the existing implementations are not quite mature
2896 or standardised, therefore trying to support them is a rare
2897 and moving target. The gain of more precision may also be offset
2898 by slowdown in computations (more bits to move around, and the
2899 operations are more likely to be executed by less optimised
2902 =head2 Seen In Perl 5.7 But Gone Now
2904 C<Time::Piece> (previously known as C<Time::Object>) was removed
2905 because it was felt that it didn't have enough value in it to be a
2906 core module. It is still a useful module, though, and is available
2909 =head1 Reporting Bugs
2911 If you find what you think is a bug, you might check the articles
2912 recently posted to the comp.lang.perl.misc newsgroup and the perl
2913 bug database at http://bugs.perl.org/ There may also be
2914 information at http://www.perl.com/ , the Perl Home Page.
2916 If you believe you have an unreported bug, please run the B<perlbug>
2917 program included with your release. Be sure to trim your bug down
2918 to a tiny but sufficient test case. Your bug report, along with the
2919 output of C<perl -V>, will be sent off to perlbug@perl.org to be
2920 analysed by the Perl porting team.
2924 The F<Changes> file for exhaustive details on what changed.
2926 The F<INSTALL> file for how to build Perl.
2928 The F<README> file for general stuff.
2930 The F<Artistic> and F<Copying> files for copyright information.
2934 Written by Jarkko Hietaniemi <F<jhi@iki.fi>>.