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 Binary Incompatibility
51 B<Perl 5.8 is not binary compatible with earlier releases of Perl.>
53 B<You have to recompile your XS modules.>
55 (Pure Perl modules should continue to work.)
57 The major reason for the discontinuity is the new IO architecture
58 called PerlIO. PerlIO is the default configuration because
59 without it many new features of Perl 5.8 cannot be used. In other
60 words: you just have to recompile your modules, sorry about that.
62 In future releases of Perl, non-PerlIO aware XS modules may become
63 completely unsupported. This shouldn't be too difficult for module
64 authors, however: PerlIO has been designed as a drop-in replacement
65 (at the source code level) for the stdio interface.
67 Depending on your platform, there are also other reasons why
68 we decided to break binary compatibility, please read on.
70 =head2 64-bit platforms and malloc
72 If your pointers are 64 bits wide, the Perl malloc is no longer being
73 used because it does not work well with 8-byte pointers. Also,
74 usually the system mallocs on such platforms are much better optimized
75 for such large memory models than the Perl malloc. Some memory-hungry
76 Perl applications like the PDL don't work well with Perl's malloc.
77 Finally, other applications than Perl (like modperl) tend to prefer
78 the system malloc. Such platforms include Alpha and 64-bit HPPA,
81 =head2 AIX Dynaloading
83 The AIX dynaloading now uses in AIX releases 4.3 and newer the native
84 dlopen interface of AIX instead of the old emulated interface. This
85 change will probably break backward compatibility with compiled
86 modules. The change was made to make Perl more compliant with other
87 applications like modperl which are using the AIX native interface.
89 =head2 Attributes for C<my> variables now handled at run-time.
91 The C<my EXPR : ATTRS> syntax now applies variable attributes at
92 run-time. (Subroutine and C<our> variables still get attributes applied
93 at compile-time.) See L<attributes> for additional details. In particular,
94 however, this allows variable attributes to be useful for C<tie> interfaces,
95 which was a deficiency of earlier releases. Note that the new semantics
96 doesn't work with the Attribute::Handlers module (as of version 0.76).
98 =head2 Socket Extension Dynamic in VMS
100 The Socket extension is now dynamically loaded instead of being
101 statically built in. This may or may not be a problem with ancient
102 TCP/IP stacks of VMS: we do not know since we weren't able to test
103 Perl in such configurations.
105 =head2 IEEE-format Floating Point Default on OpenVMS Alpha
107 Perl now uses IEEE format (T_FLOAT) as the default internal floating
108 point format on OpenVMS Alpha, potentially breaking binary compatibility
109 with external libraries or existing data. G_FLOAT is still available as
110 a configuration option. The default on VAX (D_FLOAT) has not changed.
112 =head2 New Unicode Properties
114 Unicode I<scripts> are now supported. Scripts are similar to (and superior
115 to) Unicode I<blocks>. The difference between scripts and blocks is that
116 scripts are the glyphs used by a language or a group of languages, while
117 the blocks are more artificial groupings of (mostly) 256 characters based
118 on the Unicode numbering.
120 In general, scripts are more inclusive, but not universally so. For
121 example, while the script C<Latin> includes all the Latin characters and
122 their various diacritic-adorned versions, it does not include the various
123 punctuation or digits (since they are not solely C<Latin>).
125 A number of other properties are now supported, including C<\p{L&}>,
126 C<\p{Any}> C<\p{Assigned}>, C<\p{Unassigned}>, C<\p{Blank}> and
127 C<\p{SpacePerl}> (along with their C<\P{...}> versions, of course).
128 See L<perlunicode> for details, and more additions.
130 The C<In> or C<Is> prefix to names used with the C<\p{...}> and C<\P{...}>
131 are now almost always optional. The only exception is that a C<In> prefix
132 is required to signify a Unicode block when a block name conflicts with a
133 script name. For example, C<\p{Tibetan}> refers to the script, while
134 C<\p{InTibetan}> refers to the block. When there is no name conflict, you
135 can omit the C<In> from the block name (e.g. C<\p{BraillePatterns}>), but
136 to be safe, it's probably best to always use the C<In>).
138 =head2 REF(...) Instead Of SCALAR(...)
140 A reference to a reference now stringifies as "REF(0x81485ec)" instead
141 of "SCALAR(0x81485ec)" in order to be more consistent with the return
144 =head2 pack/unpack D/F recycled
146 The undocumented pack/unpack template letters D/F have been recycled
147 for better use: now they stand for long double (if supported by the
148 platform) and NV (Perl internal floating point type). (They used
149 to be aliases for d/f, but you never knew that.)
157 The semantics of bless(REF, REF) were unclear and until someone proves
158 it to make some sense, it is forbidden.
162 The obsolete chat2 library that should never have been allowed
163 to escape the laboratory has been decommissioned.
167 The builtin dump() function has probably outlived most of its
168 usefulness. The core-dumping functionality will remain in future
169 available as an explicit call to C<CORE::dump()>, but in future
170 releases the behaviour of an unqualified C<dump()> call may change.
174 The very dusty examples in the eg/ directory have been removed.
175 Suggestions for new shiny examples welcome but the main issue is that
176 the examples need to be documented, tested and (most importantly)
181 The (bogus) escape sequences \8 and \9 now give an optional warning
182 ("Unrecognized escape passed through"). There is no need to \-escape
187 The list of filenames from glob() (or <...>) is now by default sorted
188 alphabetically to be csh-compliant (which is what happened before
189 in most UNIX platforms). (bsd_glob() does still sort platform
190 natively, ASCII or EBCDIC, unless GLOB_ALPHASORT is specified.)
194 Spurious syntax errors generated in certain situations, when glob()
195 caused File::Glob to be loaded for the first time, have been fixed.
199 Although "you shouldn't do that", it was possible to write code that
200 depends on Perl's hashed key order (Data::Dumper does this). The new
201 algorithm "One-at-a-Time" produces a different hashed key order.
202 More details are in L</"Performance Enhancements">.
206 lstat(FILEHANDLE) now gives a warning because the operation makes no sense.
207 In future releases this may become a fatal error.
211 The C<package;> syntax (C<package> without an argument) has been
212 deprecated. Its semantics were never that clear and its
213 implementation even less so. If you have used that feature to
214 disallow all but fully qualified variables, C<use strict;> instead.
218 The unimplemented POSIX regex features [[.cc.]] and [[=c=]] are still
219 recognised but now cause fatal errors. The previous behaviour of
220 ignoring them by default and warning if requested was unacceptable
221 since it, in a way, falsely promised that the features could be used.
225 The current user-visible implementation of pseudo-hashes (the weird
226 use of the first array element) is deprecated starting from Perl 5.8.0
227 and will be removed in Perl 5.10.0, and the feature will be
228 implemented differently. Not only is the current interface rather
229 ugly, but the current implementation slows down normal array and hash
230 use quite noticeably. The C<fields> pragma interface will remain
231 available. The I<restricted hashes> interface is expected to
232 be the replacement interface (see L<Hash::Util>).
236 The syntaxes C<< @a->[...] >> and C<< %h->{...} >> have now been deprecated.
240 After years of trying the suidperl is considered to be too complex to
241 ever be considered truly secure. The suidperl functionality is likely
242 to be removed in a future release.
246 The 5.005 threads model (module C<Thread>) is deprecated and expected
247 to be removed in Perl 5.10. Multithreaded code should be migrated to
248 the new ithreads model (see L<threads> and L<threads::shared>).
252 The long deprecated uppercase aliases for the string comparison
253 operators (EQ, NE, LT, LE, GE, GT) have now been removed.
257 The tr///C and tr///U features have been removed and will not return;
258 the interface was a mistake. Sorry about that. For similar
259 functionality, see pack('U0', ...) and pack('C0', ...).
263 Earlier Perls treated "sub foo (@bar)" as equivalent to "sub foo (@)".
264 The prototypes are now checked at compile-time for invalid characters.
265 An optional warning is generated ("Illegal character in prototype...")
266 but this may be upgraded to a fatal error in a future release.
270 =head1 Core Enhancements
272 =head2 PerlIO is Now The Default
278 IO is now by default done via PerlIO rather than system's "stdio".
279 PerlIO allows "layers" to be "pushed" onto a file handle to alter the
280 handle's behaviour. Layers can be specified at open time via 3-arg
283 open($fh,'>:crlf :utf8', $path) || ...
285 or on already opened handles via extended C<binmode>:
287 binmode($fh,':encoding(iso-8859-7)');
289 The built-in layers are: unix (low level read/write), stdio (as in
290 previous Perls), perlio (re-implementation of stdio buffering in a
291 portable manner), crlf (does CRLF <=> "\n" translation as on Win32,
292 but available on any platform). A mmap layer may be available if
293 platform supports it (mostly UNIXes).
295 Layers to be applied by default may be specified via the 'open' pragma.
297 See L</"Installation and Configuration Improvements"> for the effects
298 of PerlIO on your architecture name.
302 File handles can be marked as accepting Perl's internal encoding of Unicode
303 (UTF-8 or UTF-EBCDIC depending on platform) by a pseudo layer ":utf8" :
305 open($fh,">:utf8","Uni.txt");
307 Note for EBCDIC users: the pseudo layer ":utf8" is erroneously named
308 for you since it's not UTF-8 what you will be getting but instead
309 UTF-EBCDIC. See L<perlunicode>, L<utf8>, and
310 http://www.unicode.org/unicode/reports/tr16/ for more information.
311 In future releases this naming may change.
315 File handles can translate character encodings from/to Perl's internal
316 Unicode form on read/write via the ":encoding()" layer.
320 File handles can be opened to "in memory" files held in Perl scalars via:
322 open($fh,'>', \$variable) || ...
326 Anonymous temporary files are available without need to
327 'use FileHandle' or other module via
329 open($fh,"+>", undef) || ...
331 That is a literal undef, not an undefined value.
335 The list form of C<open> is now implemented for pipes (at least on UNIX):
337 open($fh,"-|", 'cat', '/etc/motd')
339 creates a pipe, and runs the equivalent of exec('cat', '/etc/motd') in
344 If your locale environment variables (LANGUAGE, LC_ALL, LC_CTYPE, LANG)
345 contain the strings 'UTF-8' or 'UTF8' (case-insensitive matching),
346 the default encoding of your STDIN, STDOUT, and STDERR, and of
347 B<any subsequent file open>, is UTF-8.
351 =head2 Restricted Hashes
353 A restricted hash is restricted to a certain set of keys, no keys
354 outside the set can be added. Also individual keys can be restricted
355 so that the key cannot be deleted and the value cannot be changed.
356 No new syntax is involved: the Hash::Util module is the interface.
360 Perl used to be fragile in that signals arriving at inopportune moments
361 could corrupt Perl's internal state. Now Perl postpones handling of
362 signals until it's safe (between opcodes).
364 This change may have surprising side effects because signals no longer
365 interrupt Perl instantly. Perl will now first finish whatever it was
366 doing, like finishing an internal operation (like sort()) or an
367 external operation (like an I/O operation), and only then look at any
368 arrived signals (and before starting the next operation). No more corrupt
369 internal state since the current operation is always finished first,
370 but the signal may take more time to get heard. Note that breaking
371 out from potentially blocking operations should still work, though.
373 =head2 Unicode Overhaul
375 Unicode in general should be now much more usable than in Perl 5.6.0
376 (or even in 5.6.1). Unicode can be used in hash keys, Unicode in
377 regular expressions should work now, Unicode in tr/// should work now,
378 Unicode in I/O should work now. See L<perluniintro> for introduction
379 and L<perlunicode> for details.
385 The Unicode Character Database coming with Perl has been upgraded
386 to Unicode 3.2.0. For more information, see http://www.unicode.org/ .
390 For developers interested in enhancing Perl's Unicode capabilities:
391 almost all the UCD files are included with the Perl distribution in
392 the F<lib/unicore subdirectory>. The most notable omission, for space
393 considerations, is the Unihan database.
397 The properties \p{Blank} and \p{SpacePerl} have been added. "Blank" is like
398 C isblank(), that is, it contains only "horizontal whitespace" (the space
399 character is, the newline isn't), and the "SpacePerl" is the Unicode
400 equivalent of C<\s> (\p{Space} isn't, since that includes the vertical
401 tabulator character, whereas C<\s> doesn't.)
403 See "New Unicode Properties" earlier in this document for additional
404 information on changes with Unicode properties.
408 =head2 Understanding of Numbers
410 In general a lot of fixing has happened in the area of Perl's
411 understanding of numbers, both integer and floating point. Since in
412 many systems the standard number parsing functions like C<strtoul()>
413 and C<atof()> seem to have bugs, Perl tries to work around their
414 deficiencies. This results hopefully in more accurate numbers.
416 Perl now tries internally to use integer values in numeric conversions
417 and basic arithmetics (+ - * /) if the arguments are integers, and
418 tries also to keep the results stored internally as integers.
419 This change leads to often slightly faster and always less lossy
420 arithmetics. (Previously Perl always preferred floating point numbers
423 =head2 Miscellaneous Changes
429 AUTOLOAD is now lvaluable, meaning that you can add the :lvalue attribute
430 to AUTOLOAD subroutines and you can assign to the AUTOLOAD return value.
434 C<perl -d:Module=arg,arg,arg> now works (previously one couldn't pass
435 in multiple arguments.)
439 The builtin dump() now gives an optional warning
440 C<dump() better written as CORE::dump()>,
441 meaning that by default C<dump(...)> is resolved as the builtin
442 dump() which dumps core and aborts, not as (possibly) user-defined
443 C<sub dump>. To call the latter, qualify the call as C<&dump(...)>.
444 (The whole dump() feature is to considered deprecated, and possibly
445 removed/changed in future releases.)
449 chomp() and chop() are now overridable. Note, however, that their
450 prototype (as given by C<prototype("CORE::chomp")> is undefined,
451 because it cannot be expressed and therefore one cannot really write
452 replacements to override these builtins.
456 END blocks are now run even if you exit/die in a BEGIN block.
457 Internally, the execution of END blocks is now controlled by
458 PL_exit_flags & PERL_EXIT_DESTRUCT_END. This enables the new
459 behaviour for Perl embedders. This will default in 5.10. See
464 Formats now support zero-padded decimal fields.
468 Lvalue subroutines can now return C<undef> in list context.
469 However, the lvalue subroutine feature still remains experimental.
473 A lost warning "Can't declare ... dereference in my" has been
474 restored (Perl had it earlier but it became lost in later releases.)
478 A new special regular expression variable has been introduced:
479 C<$^N>, which contains the most-recently closed group (submatch).
483 C<no Module;> now works even if there is no "sub unimport" in the Module.
487 The numerical comparison operators return C<undef> if either operand
488 is a NaN. Previously the behaviour was unspecified.
492 The following builtin functions are now overridable: each(), keys(),
493 pop(), push(), shift(), splice(), unshift().
497 C<pack() / unpack()> now can group template letters with C<()> and then
498 apply repetition/count modifiers on the groups.
502 C<pack() / unpack()> can now process the Perl internal numeric types:
503 IVs, UVs, NVs-- and also long doubles, if supported by the platform.
504 The template letters are C<j>, C<J>, C<F>, and C<D>.
508 C<pack('U0a*', ...)> can now be used to force a string to UTF8.
512 my __PACKAGE__ $obj now works.
516 The printf() and sprintf() now support parameter reordering using the
517 C<%\d+\$> and C<*\d+\$> syntaxes. For example
519 print "%2\$s %1\$s\n", "foo", "bar";
521 will print "bar foo\n". This feature helps in writing
522 internationalised software, and in general when the order
523 of the parameters can vary.
527 prototype(\&) is now available.
531 prototype(\[$@%&]) is now available to implicitly create references
532 (useful for example if you want to emulate the tie() interface).
536 A new command-line option, C<-t> is available. It is the
537 little brother of C<-T>: instead of dying on taint violations,
538 lexical warnings are given. B<This is only meant as a temporary
539 debugging aid while securing the code of old legacy applications.
540 This is not a substitute for -T.>
544 In other taint news, the C<exec LIST> and C<system LIST> have now been
545 considered too risky (think C<exec @ARGV>: it can start any program
546 with any arguments), and now the said forms cause a warning.
547 You should carefully launder the arguments to guarantee their
548 validity. In future releases of Perl the forms will become fatal
549 errors so consider starting laundering now.
553 Tied hash interfaces are now required to have the EXISTS and DELETE
554 methods (either own or inherited).
558 If tr/// is just counting characters, it doesn't attempt to
563 untie() will now call an UNTIE() hook if it exists. See L<perltie>
568 L<utime> now supports C<utime undef, undef, @files> to change the
569 file timestamps to the current time.
573 The rules for allowing underscores (underbars) in numeric constants
574 have been relaxed and simplified: now you can have an underscore
575 simply B<between digits>.
579 Rather than relying on C's argv[0] (which may not contain a full pathname)
580 where possible $^X is now set by asking the operating system.
581 (eg by reading F</proc/self/exe> on Linux, F</proc/curproc/file> on FreeBSD)
585 A new variable, C<${^TAINT}>, indicates whether taint mode is enabled.
589 You can now override the readline() builtin, and this overrides also
590 the <FILEHANDLE> angle bracket operator.
594 The command-line options -s and -F are now recognized on the shebang
599 Use of the C</c> match modifier without an accompanying C</g> modifier
600 elicits a new warning: C<Use of /c modifier is meaningless without /g>.
602 Use of C</c> in substitutions, even with C</g>, elicits
603 C<Use of /c modifier is meaningless in s///>.
605 Use of C</g> with C<split> elicits C<Use of /g modifier is meaningless
610 =head1 Modules and Pragmata
612 =head2 New Modules and Pragmata
618 C<Attribute::Handlers> allows a class to define attribute handlers.
621 use Attribute::Handlers;
622 sub Wolf :ATTR(SCALAR) { print "howl!\n" }
624 # later, in some package using or inheriting from MyPack...
626 my MyPack $Fluffy : Wolf; # the attribute handler Wolf will be called
628 Both variables and routines can have attribute handlers. Handlers can
629 be specific to type (SCALAR, ARRAY, HASH, or CODE), or specific to the
630 exact compilation phase (BEGIN, CHECK, INIT, or END).
634 B<B::Concise> is a new compiler backend for walking the Perl syntax
635 tree, printing concise info about ops, from Stephen McCamant. The
636 output is highly customisable. See L<B::Concise>.
640 The new bignum, bigint, and bigrat pragmas implement transparent
641 bignum support (using the Math::BigInt, Math::BigFloat, and
642 Math::BigRat backends), by Tels.
646 C<Class::ISA> for reporting the search path for a class's ISA tree,
647 by Sean Burke, has been added. See L<Class::ISA>.
651 C<Cwd> has now a split personality: if possible, an XS extension is
652 used, (this will hopefully be faster, more secure, and more robust)
653 but if not possible, the familiar Perl implementation is used.
657 C<Devel::PPPort>, originally from Kenneth Albanowski and now
658 maintained by Paul Marquess, has been added. It is primarily used
659 by C<h2xs> to enhance portability of XS modules between different
664 C<Digest>, frontend module for calculating digests (checksums), from
665 Gisle Aas, has been added. See L<Digest>.
669 C<Digest::MD5> for calculating MD5 digests (checksums) as defined in
670 RFC 1321, from Gisle Aas, has been added. See L<Digest::MD5>.
672 use Digest::MD5 'md5_hex';
674 $digest = md5_hex("Thirsty Camel");
676 print $digest, "\n"; # 01d19d9d2045e005c3f1b80e8b164de1
678 NOTE: the C<MD5> backward compatibility module is deliberately not
679 included since its further use is discouraged.
683 C<Encode>, orginally by Nick Ing-Simmons and now maintained by Dan
684 Kogai, provides a mechanism to translate between different character
685 encodings. Support for Unicode, ISO-8859-1, and ASCII are compiled in
686 to the module. Several other encodings (like the rest of the
687 ISO-8859, CP*/Win*, Mac, KOI8-R, three variants EBCDIC, Chinese,
688 Japanese, and Korean encodings) are included and can be loaded at
689 runtime. (For space considerations, the largest Chinese encodings
690 have been separated into their own CPAN module, Encode::HanExtra,
691 which Encode will use if available). See L<Encode>.
693 Any encoding supported by Encode module is also available to the
694 ":encoding()" layer if PerlIO is used.
698 C<Hash::Util> is the interface to the new I<restricted hashes>
699 feature. (Implemented by Jeffrey Friedl, Nick Ing-Simmons, and
704 C<I18N::Langinfo> can be use to query locale information.
705 See L<I18N::Langinfo>.
709 C<I18N::LangTags> has functions for dealing with RFC3066-style
710 language tags, by Sean Burke. See L<I18N::LangTags>.
714 C<ExtUtils::Constant> is a new tool for extension writers for
715 generating XS code to import C header constants, by Nicholas Clark.
716 See L<ExtUtils::Constant>.
720 C<Filter::Simple> is an easy-to-use frontend to Filter::Util::Call,
721 from Damian Conway. See L<Filter::Simple>.
727 use Filter::Simple sub {
728 while (my ($from, $to) = splice @_, 0, 2) {
737 use MyFilter qr/red/ => 'green';
739 print "red\n"; # this code is filtered, will print "green\n"
740 print "bored\n"; # this code is filtered, will print "bogreen\n"
744 print "red\n"; # this code is not filtered, will print "red\n"
748 C<File::Temp> allows one to create temporary files and directories in
749 an easy, portable, and secure way, by Tim Jenness. See L<File::Temp>.
753 C<Filter::Util::Call> provides you with the framework to write
754 I<Source Filters> in Perl, from Paul Marquess. For most uses the
755 frontend Filter::Simple is to be preferred. See L<Filter::Util::Call>.
759 C<if> is a new pragma for conditional inclusion of modules, from
764 L<libnet> is a collection of perl5 modules related to network
765 programming, from Graham Barr. See L<Net::FTP>, L<Net::NNTP>,
766 L<Net::Ping> (not part of libnet, but related), L<Net::POP3>,
767 L<Net::SMTP>, and L<Net::Time>.
769 Perl installation leaves libnet unconfigured, use F<libnetcfg> to configure.
773 C<List::Util> is a selection of general-utility list subroutines, like
774 sum(), min(), first(), and shuffle(), by Graham Barr. See L<List::Util>.
778 C<Locale::Constants>, C<Locale::Country>, C<Locale::Currency>
779 C<Locale::Language>, and L<Locale::Script>, from Neil Bowers, have
780 been added. They provide the codes for various locale standards, such
781 as "fr" for France, "usd" for US Dollar, and "ja" for Japanese.
785 $country = code2country('jp'); # $country gets 'Japan'
786 $code = country2code('Norway'); # $code gets 'no'
788 See L<Locale::Constants>, L<Locale::Country>, L<Locale::Currency>,
789 and L<Locale::Language>.
793 C<Locale::Maketext> is localization framework from Sean Burke. See
794 L<Locale::Maketext>, and L<Locale::Maketext::TPJ13>. The latter is an
795 article about software localization, originally published in The Perl
796 Journal #13, republished here with kind permission.
800 C<Math::BigRat> for big rational numbers, to accompany Math::BigInt and
801 Math::BigFloat, from Tels.
805 C<Memoize> can make your functions faster by trading space for time,
806 from Mark-Jason Dominus. See L<Memoize>.
810 C<MIME::Base64> allows you to encode data in base64, from Gisle Aas,
811 as defined in RFC 2045 - I<MIME (Multipurpose Internet Mail
816 $encoded = encode_base64('Aladdin:open sesame');
817 $decoded = decode_base64($encoded);
819 print $encoded, "\n"; # "QWxhZGRpbjpvcGVuIHNlc2FtZQ=="
825 C<MIME::QuotedPrint> allows you to encode data in quoted-printable
826 encoding, as defined in RFC 2045 - I<MIME (Multipurpose Internet Mail
827 Extensions)>, from Gisle Aas.
829 use MIME::QuotedPrint;
831 $encoded = encode_qp("Smiley in Unicode: \x{263a}");
832 $decoded = decode_qp($encoded);
834 print $encoded, "\n"; # "Smiley in Unicode: =263A"
836 MIME::QuotedPrint has been enhanced to provide the basic methods
837 necessary to use it with PerlIO::Via as in :
839 use MIME::QuotedPrint;
840 open($fh,">Via(MIME::QuotedPrint)",$path);
842 See L<MIME::QuotedPrint>.
846 C<NEXT> is pseudo-class for method redispatch, from Damian Conway.
851 C<open> is a new pragma for setting the default I/O disciplines
856 C<PerlIO::Scalar> provides the implementation of IO to "in memory"
857 Perl scalars as discussed above, from Nick Ing-Simmons. It also
858 serves as an example of a loadable PerlIO layer. Other future
859 possibilities include PerlIO::Array and PerlIO::Code.
860 See L<PerlIO::Scalar>.
864 C<PerlIO::Via> acts as a PerlIO layer and wraps PerlIO layer
865 functionality provided by a class (typically implemented in perl
866 code), from Nick Ing-Simmons.
868 use MIME::QuotedPrint;
869 open($fh,">Via(MIME::QuotedPrint)",$path);
871 This will automatically convert everything output to C<$fh>
872 to Quoted-Printable. See L<PerlIO::Via>.
876 C<Pod::ParseLink>, by Russ Allbery, has been added,
877 to parse LZ<><> links in pods as described in the new
882 C<Pod::Text::Overstrike>, by Joe Smith, has been added.
883 It converts POD data to formatted overstrike text.
884 See L<Pod::Text::Overstrike>.
888 C<Scalar::Util> is a selection of general-utility scalar subroutines,
889 like blessed(), reftype(), and tainted(). See L<Scalar::Util>.
893 C<sort> is a new pragma for controlling the behaviour of sort().
897 C<Storable> gives persistence to Perl data structures by allowing the
898 storage and retrieval of Perl data to and from files in a fast and
899 compact binary format. Because in effect Storable does serialisation
900 of Perl data structues, with it you can also clone deep, hierarchical
901 datastructures. Storable was originally created by Raphael Manfredi,
902 but it is now maintained by Abhijit Menon-Sen. Storable has been
903 enhanced to understand the two new hash features, Unicode keys and
904 restricted hashes. See L<Storable>.
908 C<Switch>, from Damian Conway, has been added. Just by saying
912 you have C<switch> and C<case> available in Perl.
918 case 1 { print "number 1" }
919 case "a" { print "string a" }
920 case [1..10,42] { print "number in list" }
921 case (@array) { print "number in list" }
922 case /\w+/ { print "pattern" }
923 case qr/\w+/ { print "pattern" }
924 case (%hash) { print "entry in hash" }
925 case (\%hash) { print "entry in hash" }
926 case (\&sub) { print "arg to subroutine" }
927 else { print "previous case not true" }
934 C<Test::More> is yet another framework for writing test scripts,
935 more extensive than Test::Simple, by Michael Schwern. See L<Test::More>.
939 C<Test::Simple> has basic utilities for writing tests, by Michael
940 Schwern. See L<Test::Simple>.
944 C<Text::Balanced> has been added, for extracting delimited text
945 sequences from strings, from Damian Conway.
947 use Text::Balanced 'extract_delimited';
949 ($a, $b) = extract_delimited("'never say never', he never said", "'", '');
951 $a will be "'never say never'", $b will be ', he never said'.
953 In addition to extract_delimited() there are also extract_bracketed(),
954 extract_quotelike(), extract_codeblock(), extract_variable(),
955 extract_tagged(), extract_multiple(), gen_delimited_pat(), and
956 gen_extract_tagged(). With these you can implement rather advanced
957 parsing algorithms. See L<Text::Balanced>.
961 C<threads> is an interface to interpreter threads, by Arthur Bergman.
962 Interpreter threads (ithreads) is the new thread model introduced in
963 Perl 5.6 but only available as an internal interface for extension
964 writers (and for Win32 Perl for C<fork()> emulation). See L<threads>.
968 C<threads::shared> allows data sharing for interpreter threads, from
969 Arthur Bergman. In the ithreads model any data sharing between
970 threads must be explicit, as opposed to the old 5.005 thread model
971 where data sharing was implicit. See L<threads::shared>.
975 C<Tie::File>, by Mark-Jason Dominus, associates a Perl array with the
980 C<Tie::Memoize>, by Ilya Zakharevich, provides on-demand loaded hashes.
984 C<Tie::RefHash::Nestable>, by Edward Avis, allows storing hash
985 references (unlike the standard Tie::RefHash) The module is contained
986 within Tie::RefHash, see L<Tie::RefHash>.
990 C<Time::HiRes> provides high resolution timing (ualarm, usleep,
991 and gettimeofday), from Douglas E. Wegscheid. See L<Time::HiRes>.
995 C<Unicode::UCD> offers a querying interface to the Unicode Character
996 Database. See L<Unicode::UCD>.
1000 C<Unicode::Collate> implements the UCA (Unicode Collation Algorithm)
1001 for sorting Unicode strings, by SADAHIRO Tomoyuki. See L<Unicode::Collate>.
1005 C<Unicode::Normalize> implements the various Unicode normalization
1006 forms, by SADAHIRO Tomoyuki. See L<Unicode::Normalize>.
1010 C<XS::Typemap>, by Tim Jenness, is a test extension that exercises XS
1011 typemaps. Nothing gets installed but for extension writers the code
1016 =head2 Updated And Improved Modules and Pragmata
1022 The following independently supported modules have been updated to the
1023 newest versions from CPAN: CGI, CPAN, DB_File, File::Spec, File::Temp,
1024 Getopt::Long, Math::BigFloat, Math::BigInt, the podlators bundle
1025 (Pod::Man, Pod::Text), Pod::LaTeX, Pod::Parser, Storable,
1026 Term::ANSIColor, Test, Text-Tabs+Wrap.
1030 The attributes::reftype() now works on tied arguments.
1034 AutoLoader can now be disabled with C<no AutoLoader;>.
1038 B::Deparse has been significantly enhanced. It now can deparse almost
1039 all of the standard test suite (so that the tests still succeed).
1040 There is a make target "test.deparse" for trying this out.
1044 Class::Struct can now define the classes in compile time.
1048 Class::Struct now assigns the array/hash element if the accessor
1049 is called with an array/hash element as the B<sole> argument.
1053 The return value of Cwd::fastcwd() is now tainted.
1057 Data::Dumper has now an option to sort hashes.
1061 Data::Dumper has now an option to dump code references
1066 DB_File now supports newer Berkeley DB versions, among
1071 Devel::Peek now has an interface for the Perl memory statistics
1072 (this works only if you are using perl's malloc, and if you have
1073 compiled with debugging).
1077 The English module can now be used without the infamous performance
1080 use English '-no_match_vars';
1082 (Assuming, of course, that one doesn't need the troublesome variables
1083 C<$`>, C<$&>, or C<$'>.) Also, introduced C<@LAST_MATCH_START> and
1084 C<@LAST_MATCH_END> English aliases for C<@-> and C<@+>.
1088 ExtUtils::MakeMaker now uses File::Spec internally, which hopefully
1089 leads into better portability.
1093 Fcntl, Socket, and Sys::Syslog have been rewritten to use the
1094 new-style constant dispatch section (see L<ExtUtils::Constant>).
1095 This means that they will be more robust and hopefully faster.
1099 File::Find now chdir()s correctly when chasing symbolic links.
1103 File::Find now has pre- and post-processing callbacks. It also
1104 correctly changes directories when chasing symbolic links. Callbacks
1105 (naughtily) exiting with "next;" instead of "return;" now work.
1109 File::Find is now (again) reentrant. It also has been made
1114 The warnings issued by File::Find now belong to their own category.
1115 You can enable/disable them with C<use/no warnings 'File::Find';>.
1119 File::Glob::glob() renamed to File::Glob::bsd_glob() to avoid
1120 prototype mismatch with CORE::glob().
1124 File::Glob now supports C<GLOB_LIMIT> constant to limit the size of
1125 the returned list of filenames.
1129 IPC::Open3 now allows the use of numeric file descriptors.
1133 IO::Socket has now atmark() method, which returns true if the socket
1134 is positioned at the out-of-band mark. The method is also exportable
1135 as a sockatmark() function.
1139 IO::Socket::INET has support for ReusePort option (if your platform
1140 supports it). The Reuse option now has an alias, ReuseAddr. For clarity
1141 you may want to prefer ReuseAddr.
1145 IO::Socket::INET now supports C<LocalPort> of zero (usually meaning
1146 that the operating system will make one up.)
1150 use lib now works identically to @INC. Removing directories
1151 with 'no lib' now works.
1155 Math::BigFloat and Math::BigInt have undergone a full rewrite.
1156 They are now magnitudes faster, and they support various
1157 bignum libraries such as GMP and PARI as their backends.
1161 Math::Complex handles inf, NaN etc., better.
1165 Net::Ping has been muchly enhanced: multihoming is now supported,
1166 Win32 functionality is better, there is now time measuring
1167 functionality (optionally high-resolution using Time::HiRes),
1168 and there is now "external" protocol which uses Net::Ping::External
1169 module which runs your external ping utility and parses the output.
1170 A version of Net::Ping::External is available in CPAN.
1172 Note that some of the Net::Ping tests are disabled when running
1173 under the Perl distribution since one cannot assume one or more
1174 of the following: enabled echo port at localhost, full Internet
1175 connectivity, or sympathetic firewalls. You can set the environment
1176 variable PERL_TEST_Net_Ping to "1" (one) before running the Perl test
1177 suite to enable all the Net::Ping tests.
1181 POSIX::sigaction() is now much more flexible and robust.
1182 You can now install coderef handlers, 'DEFAULT', and 'IGNORE'
1183 handlers, installing new handlers was not atomic.
1187 In Safe the C<%INC> now localised in a Safe compartment so that
1192 In SDBM_File on dosish platforms, some keys went missing because of
1193 lack of support for files with "holes". A workaround for the problem
1198 In Search::Dict one can now have a pre-processing hook for the
1199 lines being searched.
1203 The Shell module now has an OO interface.
1207 In Sys::Syslog there is now a failover mechanism that will go
1208 through alternative connection mechanisms until the message
1209 is successfully logged.
1213 The Test module has been significantly enhanced.
1217 Time::Local::timelocal() does not handle fractional seconds anymore.
1218 The rationale is that neither does localtime(), and timelocal() and
1219 localtime() are supposed to be inverses of each other.
1223 The vars pragma now supports declaring fully qualified variables.
1224 (Something that C<our()> does not and will not support.)
1228 The C<utf8::> name space (as in the pragma) provides various
1229 Perl-callable functions to provide low level access to Perl's
1230 internal Unicode representation. At the moment only length()
1231 has been implemented.
1235 =head1 Utility Changes
1241 Emacs perl mode (emacs/cperl-mode.el) has been updated to version
1246 F<emacs/e2ctags.pl> is now much faster.
1250 C<enc2xs> is a tool for people adding their own encodings to the
1255 C<h2ph> now supports C trigraphs.
1259 C<h2xs> now produces a template README.
1263 C<h2xs> now uses C<Devel::PPort> for better portability between
1264 different versions of Perl.
1268 C<h2xs> uses the new L<ExtUtils::Constant> module which will affect
1269 newly created extensions that define constants. Since the new code is
1270 more correct (if you have two constants where the first one is a
1271 prefix of the second one, the first constant B<never> gets defined),
1272 less lossy (it uses integers for integer constant, as opposed to the
1273 old code that used floating point numbers even for integer constants),
1274 and slightly faster, you might want to consider regenerating your
1275 extension code (the new scheme makes regenerating easy).
1276 L<h2xs> now also supports C trigraphs.
1280 C<libnetcfg> has been added to configure the libnet.
1284 C<perlbug> is now much more robust. It also sends the bug report to
1285 perl.org, not perl.com.
1289 C<perlcc> has been rewritten and its user interface (that is,
1290 command line) is much more like that of the UNIX C compiler, cc.
1291 (The perlbc tools has been removed. Use C<perlcc -B> instead.)
1295 C<perlivp> is a new Installation Verification Procedure utility
1296 for running any time after installing Perl.
1300 C<piconv> is an implementation of the character conversion utility
1301 C<iconv>, demonstrating the new Encode module.
1305 C<pod2html> now allows specifying a cache directory.
1309 C<pod2html> now produces XHTML 1.0.
1313 C<pod2html> now understands POD written using different line endings
1314 (PC-like CRLF versus UNIX-like LF versus MacClassic-like CR).
1318 C<s2p> has been completely rewritten in Perl. (It is in fact a full
1319 implementation of sed in Perl: you can use the sed functionality by
1320 using the C<psed> utility.)
1324 C<xsubpp> now understands POD documentation embedded in the *.xs files.
1328 C<xsubpp> now supports OUT keyword.
1332 =head1 New Documentation
1338 perl56delta details the changes between the 5.005 release and the
1343 perlclib documents the internal replacements for standard C library
1344 functions. (Interesting only for extension writers and Perl core
1349 perldebtut is a Perl debugging tutorial.
1353 perlebcdic contains considerations for running Perl on EBCDIC platforms.
1357 perlintro is a gentle introduction to Perl.
1361 perliol documents the internals of PerlIO with layers.
1365 perlmodstyle is a style guide for writing modules.
1369 perlnewmod tells about writing and submitting a new module.
1373 perlpacktut is a pack() tutorial.
1377 perlpod has been rewritten to be clearer and to record the best
1378 practices gathered over the years.
1382 perlpodspec is a more formal specification of the pod format,
1383 mainly of interest for writers of pod applications, not to
1384 people writing in pod.
1388 perlretut is a regular expression tutorial.
1392 perlrequick is a regular expressions quick-start guide.
1393 Yes, much quicker than perlretut.
1397 perltodo has been updated.
1401 perltootc has been renamed as perltooc (to not to conflict
1402 with perltoot in filesystems restricted to "8.3" names)
1406 perluniintro is an introduction to using Unicode in Perl.
1407 (perlunicode is more of a detailed reference and background
1412 perlutil explains the command line utilities packaged with the Perl
1417 The following platform-specific documents are available before
1418 the installation as README.I<platform>, and after the installation
1421 perlaix perlamiga perlapollo perlbeos perlbs2000
1422 perlce perlcygwin perldgux perldos perlepoc perlhpux
1423 perlhurd perlmachten perlmacos perlmint perlmpeix
1424 perlnetware perlos2 perlos390 perlplan9 perlqnx perlsolaris
1425 perltru64 perluts perlvmesa perlvms perlvos perlwin32
1431 The documentation for the POSIX-BC platform is called "BS2000", to avoid
1432 confusion with the Perl POSIX module.
1436 The documentation for the WinCE platform is called perlce (README.ce
1437 in the source code kit), to avoid confusion with the perlwin32
1438 documentation on 8.3-restricted filesystems.
1442 =head1 Performance Enhancements
1448 map() could get pathologically slow when the result list it generates
1449 is larger than the source list. The performance has been improved for
1454 sort() has been changed to use primarily mergesort internally as
1455 opposed to the earlier quicksort. For very small lists this may
1456 result in slightly slower sorting times, but in general the speedup
1457 should be at least 20%. Additional bonuses are that the worst case
1458 behaviour of sort() is now better (in computer science terms it now
1459 runs in time O(N log N), as opposed to quicksort's Theta(N**2)
1460 worst-case run time behaviour), and that sort() is now stable
1461 (meaning that elements with identical keys will stay ordered as they
1462 were before the sort). See the C<sort> pragma for information.
1464 The story in more detail: suppose you want to serve yourself a little
1467 @digits = ( 3,1,4,1,5,9 );
1469 A numerical sort of the digits will yield (1,1,3,4,5,9), as expected.
1470 Which C<1> comes first is hard to know, since one C<1> looks pretty
1471 much like any other. You can regard this as totally trivial,
1472 or somewhat profound. However, if you just want to sort the even
1473 digits ahead of the odd ones, then what will
1475 sort { ($a % 2) <=> ($b % 2) } @digits;
1477 yield? The only even digit, C<4>, will come first. But how about
1478 the odd numbers, which all compare equal? With the quicksort algorithm
1479 used to implement Perl 5.6 and earlier, the order of ties is left up
1480 to the sort. So, as you add more and more digits of Pi, the order
1481 in which the sorted even and odd digits appear will change.
1482 and, for sufficiently large slices of Pi, the quicksort algorithm
1483 in Perl 5.8 won't return the same results even if reinvoked with the
1484 same input. The justification for this rests with quicksort's
1485 worst case behavior. If you run
1487 sort { $a <=> $b } ( 1 .. $N , 1 .. $N );
1489 (something you might approximate if you wanted to merge two sorted
1490 arrays using sort), doubling $N doesn't just double the quicksort time,
1491 it I<quadruples> it. Quicksort has a worst case run time that can
1492 grow like N**2, so-called I<quadratic> behaviour, and it can happen
1493 on patterns that may well arise in normal use. You won't notice this
1494 for small arrays, but you I<will> notice it with larger arrays,
1495 and you may not live long enough for the sort to complete on arrays
1496 of a million elements. So the 5.8 quicksort scrambles large arrays
1497 before sorting them, as a statistical defence against quadratic behaviour.
1498 But that means if you sort the same large array twice, ties may be
1499 broken in different ways.
1501 Because of the unpredictability of tie-breaking order, and the quadratic
1502 worst-case behaviour, quicksort was I<almost> replaced completely with
1503 a stable mergesort. I<Stable> means that ties are broken to preserve
1504 the original order of appearance in the input array. So
1506 sort { ($a % 2) <=> ($b % 2) } (3,1,4,1,5,9);
1508 will yield (4,3,1,1,5,9), guaranteed. The even and odd numbers
1509 appear in the output in the same order they appeared in the input.
1510 Mergesort has worst case O(NlogN) behaviour, the best value
1511 attainable. And, ironically, this mergesort does particularly
1512 well where quicksort goes quadratic: mergesort sorts (1..$N, 1..$N)
1513 in O(N) time. But quicksort was rescued at the last moment because
1514 it is faster than mergesort on certain inputs and platforms.
1515 For example, if you really I<don't> care about the order of even
1516 and odd digits, quicksort will run in O(N) time; it's very good
1517 at sorting many repetitions of a small number of distinct elements.
1518 The quicksort divide and conquer strategy works well on platforms
1519 with relatively small, very fast, caches. Eventually, the problem gets
1520 whittled down to one that fits in the cache, from which point it
1521 benefits from the increased memory speed.
1523 Quicksort was rescued by implementing a sort pragma to control aspects
1524 of the sort. The B<stable> subpragma forces stable behaviour,
1525 regardless of algorithm. The B<_quicksort> and B<_mergesort>
1526 subpragmas are heavy-handed ways to select the underlying implementation.
1527 The leading C<_> is a reminder that these subpragmas may not survive
1528 beyond 5.8. More appropriate mechanisms for selecting the implementation
1529 exist, but they wouldn't have arrived in time to save quicksort.
1533 Hashes now use Bob Jenkins "One-at-a-Time" hashing key algorithm
1534 ( http://burtleburtle.net/bob/hash/doobs.html ). This algorithm is
1535 reasonably fast while producing a much better spread of values than
1536 the old hashing algorithm (originally by Chris Torek, later tweaked by
1537 Ilya Zakharevich). Hash values output from the algorithm on a hash of
1538 all 3-char printable ASCII keys comes much closer to passing the
1539 DIEHARD random number generation tests. According to perlbench, this
1540 change has not affected the overall speed of Perl.
1544 unshift() should now be noticeably faster.
1548 =head1 Installation and Configuration Improvements
1550 =head2 Generic Improvements
1556 INSTALL now explains how you can configure Perl to use 64-bit
1557 integers even on non-64-bit platforms.
1561 Policy.sh policy change: if you are reusing a Policy.sh file
1562 (see INSTALL) and you use Configure -Dprefix=/foo/bar and in the old
1563 Policy $prefix eq $siteprefix and $prefix eq $vendorprefix, all of
1564 them will now be changed to the new prefix, /foo/bar. (Previously
1565 only $prefix changed.) If you do not like this new behaviour,
1566 specify prefix, siteprefix, and vendorprefix explicitly.
1570 A new optional location for Perl libraries, otherlibdirs, is available.
1571 It can be used for example for vendor add-ons without disturbing Perl's
1572 own library directories.
1576 In many platforms the vendor-supplied 'cc' is too stripped-down to
1577 build Perl (basically, 'cc' doesn't do ANSI C). If this seems
1578 to be the case and 'cc' does not seem to be the GNU C compiler
1579 'gcc', an automatic attempt is made to find and use 'gcc' instead.
1583 gcc needs to closely track the operating system release to avoid
1584 build problems. If Configure finds that gcc was built for a different
1585 operating system release than is running, it now gives a clearly visible
1586 warning that there may be trouble ahead.
1590 Since Perl 5.8 is not binary-compatible with previous releases
1591 of Perl, Configure no longer suggests including the 5.005
1596 Configure C<-S> can now run non-interactively.
1600 Configure support for pdp11-style memory models has been removed due
1605 configure.gnu now works with options with whitespace in them.
1609 installperl now outputs everything to STDERR.
1613 $Config{byteorder} is now computed dynamically (this is more robust
1614 with "fat binaries" where an executable image contains binaries for
1615 more than one binary platform.)
1619 Because PerlIO is now the default on most platforms, "-perlio" doesn't
1620 get appended to the $Config{archname} (also known as $^O) anymore.
1621 Instead, if you explicitly choose not to use perlio (Configure command
1622 line option -Uuseperlio), you will get "-stdio" appended.
1626 Another change related to the architecture name is that "-64all"
1627 (-Duse64bitall, or "maximally 64-bit") is appended only if your
1628 pointers are 64 bits wide. (To be exact, the use64bitall is ignored.)
1632 In AFS installations one can configure the root of the AFS to be
1633 somewhere else than the default F</afs> by using the Configure
1634 parameter C<-Dafsroot=/some/where/else>.
1638 APPLLIB_EXP, a less-know configuration-time definition, has been
1639 documented. It can be used to prepend site-specific directories
1640 to Perl's default search path (@INC), see INSTALL for information.
1644 The version of Berkeley DB used when the Perl (and, presumably, the
1645 DB_File extension) was built is now available as
1646 C<@Config{qw(db_version_major db_version_minor db_version_patch)}>
1647 from Perl and as C<DB_VERSION_MAJOR_CFG DB_VERSION_MINOR_CFG
1648 DB_VERSION_PATCH_CFG> from C.
1652 Building Berkeley DB3 for compatibility modes for DB, NDBM, and ODBM
1653 has been documented in INSTALL.
1657 If you have CPAN access (either network or a local copy such as a
1658 CD-ROM) you can during specify extra modules to Configure to build and
1659 install with Perl using the -Dextras=... option. See INSTALL for
1664 In addition to config.over a new override file, config.arch, is
1665 available. That is supposed to be used by hints file writers for
1666 architecture-wide changes (as opposed to config.over which is for
1671 If your file system supports symbolic links you can build Perl outside
1672 of the source directory by
1674 mkdir /tmp/perl/build/directory
1675 cd /tmp/perl/build/directory
1676 sh /path/to/perl/source/Configure -Dmksymlinks ...
1678 This will create in /tmp/perl/build/directory a tree of symbolic links
1679 pointing to files in /path/to/perl/source. The original files are left
1680 unaffected. After Configure has finished you can just say
1684 and Perl will be built and tested, all in /tmp/perl/build/directory.
1688 For Perl developers several new make targets for profiling
1689 and debugging have been added, see L<perlhack>.
1695 Use of the F<gprof> tool to profile Perl has been documented in
1696 L<perlhack>. There is a make target called "perl.gprof" for
1697 generating a gprofiled Perl executable.
1701 If you have GCC 3, there is a make target called "perl.gcov" for
1702 creating a gcoved Perl executable for coverage analysis. See
1707 If you are on IRIX or Tru64 platforms, new profiling/debugging options
1708 have been added, see L<perlhack> for more information about pixie and
1715 Guidelines of how to construct minimal Perl installations have
1716 been added to INSTALL.
1720 The Thread extension is now not built at all under ithreads
1721 (C<Configure -Duseithreads>) because it wouldn't work anyway (the
1722 Thread extension requires being Configured with C<-Duse5005threads>).
1724 But note that the Thread.pm interface is now shared by both
1729 The Gconvert macro ($Config{d_Gconvert}) used by perl for stringifying
1730 floating-point numbers is now more picky about using sprintf %.*g
1731 rules for the conversion. Some platforms that used to use gcvt may
1732 now resort to the slower sprintf.
1736 The obsolete method of making a special (e.g., debugging) flavor
1739 make LIBPERL=libperld.a
1741 has been removed. Use -DDEBUGGING instead.
1745 =head2 New Or Improved Platforms
1747 For the list of platforms known to support Perl,
1748 see L<perlport/"Supported Platforms">.
1754 AIX dynamic loading should be now better supported.
1758 AIX should now work better with gcc, threads, and 64-bitness. Also the
1759 long doubles support in AIX should be better now. See L<perlaix>.
1763 AtheOS ( http://www.atheos.cx/ ) is a new platform.
1767 BeOS has been reclaimed.
1771 DG/UX platform now supports the 5.005-style threads. See L<perldgux>.
1775 DYNIX/ptx platform (a.k.a. dynixptx) is supported at or near osvers 4.5.2.
1779 EBCDIC platforms (z/OS, also known as OS/390, POSIX-BC, and VM/ESA)
1780 have been regained. Many test suite tests still fail and the
1781 co-existence of Unicode and EBCDIC isn't quite settled, but the
1782 situation is much better than with Perl 5.6. See L<perlos390>,
1783 L<perlbs2000> (for POSIX-BC), and L<perlvmesa> for more information.
1787 Building perl with -Duseithreads or -Duse5005threads now works under
1788 HP-UX 10.20 (previously it only worked under 10.30 or later). You will
1789 need a thread library package installed. See README.hpux.
1793 MacOS Classic (MacPerl has of course been available since
1794 perl 5.004 but now the source code bases of standard Perl
1795 and MacPerl have been synchronised)
1799 MacOS X (or Darwin) should now be able to build Perl even on HFS+
1800 filesystems. (The case-insensitivity confused the Perl build process.)
1804 NCR MP-RAS is now supported.
1808 All the NetBSD specific patches (except for the installation
1809 specific ones) have been merged back to the main distribution.
1813 NetWare from Novell is now supported. See L<perlnetware>.
1817 NonStop-UX is now supported.
1821 NEC SUPER-UX is now supported.
1825 All the OpenBSD specific patches (except for the installation
1826 specific ones) have been merged back to the main distribution.
1830 Perl has been tested with the GNU pth userlevel thread package
1831 ( http://www.gnu.org/software/pth/pth.html ) . All but one thread
1832 test worked, and that one failure was because of test results arriving
1833 in unexpected order.
1837 Stratus VOS is now supported using Perl's native build method
1838 (Configure). This is the recommended method to build Perl on
1839 VOS. The older methods, which build miniperl, are still
1840 available. See L<perlvos>.
1844 Amdahl UTS UNIX mainframe platform is now supported.
1848 WinCE is now supported. See L<perlce>.
1852 z/OS (formerly known as OS/390, formerly known as MVS OE) has now
1853 support for dynamic loading. This is not selected by default,
1854 however, you must specify -Dusedl in the arguments of Configure.
1858 =head1 Selected Bug Fixes
1860 Numerous memory leaks and uninitialized memory accesses have been
1861 hunted down. Most importantly anonymous subs used to leak quite
1868 The autouse pragma didn't work for Multi::Part::Function::Names.
1872 caller() could cause core dumps in certain situations. Carp was sometimes
1873 affected by this problem. In particular, caller() now returns a
1874 subroutine name of C<(unknown)> for subroutines that have been removed
1875 from the symbol table.
1879 chop(@list) in list context returned the characters chopped in
1880 reverse order. This has been reversed to be in the right order.
1884 Configure no longer includes the DBM libraries (dbm, gdbm, db, ndbm)
1885 when building the Perl binary. The only exception to this is SunOS 4.x,
1890 The behaviour of non-decimal but numeric string constants such as
1891 "0x23" was platform-dependent: in some platforms that was seen as 35,
1892 in some as 0, in some as a floating point number (don't ask). This
1893 was caused by Perl using the operating system libraries in a situation
1894 where the result of the string to number conversion is undefined: now
1895 Perl consistently handles such strings as zero in numeric contexts.
1899 The order of DESTROYs has been made more predictable.
1903 Several debugger fixes: exit code now reflects the script exit code,
1904 condition C<"0"> now treated correctly, the C<d> command now checks
1905 line number, the C<$.> no longer gets corrupted, all debugger output
1906 now goes correctly to the socket if RemotePort is set.
1910 Perl 5.6.0 could emit spurious warnings about redefinition of dl_error()
1911 when statically building extensions into perl. This has been corrected.
1915 L<dprofpp> -R didn't work.
1919 C<*foo{FORMAT}> now works.
1923 Infinity is now recognized as a number.
1927 UNIVERSAL::isa no longer caches methods incorrectly. (This broke
1928 the Tk extension with 5.6.0.)
1932 Lexicals I: lexicals outside an eval "" weren't resolved
1933 correctly inside a subroutine definition inside the eval "" if they
1934 were not already referenced in the top level of the eval""ed code.
1938 Lexicals II: lexicals leaked at file scope into subroutines that
1939 were declared before the lexicals.
1943 Lexical warnings now propagating correctly between scopes
1944 and into C<eval "...">.
1948 C<use warnings qw(FATAL all)> did not work as intended. This has been
1953 warnings::enabled() now reports the state of $^W correctly if the caller
1954 isn't using lexical warnings.
1958 Line renumbering with eval and C<#line> now works.
1962 Fixed numerous memory leaks, especially in eval "".
1966 Localised tied variables no more leak memory
1969 tie my %tied_hash => 'Tie::StdHash';
1973 # Used to leak memory every time local() was called,
1974 # in a loop this added up.
1975 local($tied_hash{Foo}) = 1;
1979 Localised hash elements (and %ENV) are correctly unlocalised to not to
1980 exist, if that's what they were.
1984 tie my %tied_hash => 'Tie::StdHash';
1988 # Nothing has set the FOO element so far
1990 { local $tied_hash{FOO} = 'Bar' }
1992 # Here the FOO element would have been C<undef>,
1995 As a side effect of this fix, tied hash interfaces B<must> define
1996 the EXISTS and DELETE methods.
2000 mkdir() now ignores trailing slashes in the directory name,
2001 as mandated by POSIX.
2005 Some versions of glibc have a broken modfl(). This affects builds
2006 with C<-Duselongdouble>. This version of Perl detects this brokenness
2007 and has a workaround for it. The glibc release 2.2.2 is known to have
2008 fixed the modfl() bug.
2012 Modulus of unsigned numbers now works (4063328477 % 65535 used to
2013 return 27406, instead of 27047).
2017 Some "not a number" warnings introduced in 5.6.0 eliminated to be
2018 more compatible with 5.005. Infinity is now recognised as a number.
2022 Numeric conversions did not recognize changes in the string value
2023 properly in certain circumstances.
2027 Attributes (like :shared) didn't work with our().
2031 our() variables will not cause "will not stay shared" warnings.
2035 "our" variables of the same name declared in two sibling blocks
2036 resulted in bogus warnings about "redeclaration" of the variables.
2037 The problem has been corrected.
2041 pack "Z" now correctly terminates the string with "\0".
2045 Fix password routines which in some shadow password platforms
2046 (e.g. HP-UX) caused getpwent() to return every other entry.
2050 The PERL5OPT environment variable (for passing command line arguments
2051 to Perl) didn't work for more than a single group of options.
2055 PERL5OPT with embedded spaces didn't work.
2059 printf() no longer resets the numeric locale to "C".
2063 C<qw(a\\b)> now parses correctly as C<'a\\b'>.
2067 pos() did not return the correct value within s///ge in earlier
2068 versions. This is now handled correctly.
2072 Printing quads (64-bit integers) with printf/sprintf now works
2073 without the q L ll prefixes (assuming you are on a quad-capable platform).
2077 Regular expressions on references and overloaded scalars now work.
2081 Right-hand side magic (GMAGIC) could in many cases such as string
2082 concatenation be invoked too many times.
2086 scalar() now forces scalar context even when used in void context.
2090 SOCKS support is now much more robust.
2094 sort() arguments are now compiled in the right wantarray context
2095 (they were accidentally using the context of the sort() itself).
2096 The comparison block is now run in scalar context, and the arguments
2097 to be sorted are always provided list context.
2101 Changed the POSIX character class C<[[:space:]]> to include the (very
2102 rarely used) vertical tab character. Added a new POSIX-ish character
2103 class C<[[:blank:]]> which stands for horizontal whitespace
2104 (currently, the space and the tab).
2108 The tainting behaviour of sprintf() has been rationalized. It does
2109 not taint the result of floating point formats anymore, making the
2110 behaviour consistent with that of string interpolation.
2114 Some cases of inconsistent taint propagation (such as within hash
2115 values) have been fixed.
2119 The RE engine found in Perl 5.6.0 accidentally pessimised certain kinds
2120 of simple pattern matches. These are now handled better.
2124 Regular expression debug output (whether through C<use re 'debug'>
2125 or via C<-Dr>) now looks better.
2129 Multi-line matches like C<"a\nxb\n" =~ /(?!\A)x/m> were flawed. The
2134 Use of $& could trigger a core dump under some situations. This
2139 The regular expression captured submatches ($1, $2, ...) are now
2140 more consistently unset if the match fails, instead of leaving false
2141 data lying around in them.
2145 readline() on files opened in "slurp" mode could return an extra "" at
2146 the end in certain situations. This has been corrected.
2150 Autovivification of symbolic references of special variables described
2151 in L<perlvar> (as in C<${$num}>) was accidentally disabled. This works
2156 Sys::Syslog ignored the C<LOG_AUTH> constant.
2160 All but the first argument of the IO syswrite() method are now optional.
2164 $AUTOLOAD, sort(), lock(), and spawning subprocesses
2165 in multiple threads simultaneously are now thread-safe.
2169 Tie::ARRAY SPLICE method was broken.
2173 Allow read-only string on left hand side of non-modifying tr///.
2177 If C<STDERR> is tied, warnings caused by C<warn> and C<die> now
2178 correctly pass to it.
2182 Several Unicode fixes.
2188 BOMs (byte order marks) in the beginning of Perl files
2189 (scripts, modules) should now be transparently skipped.
2190 UTF-16 (UCS-2) encoded Perl files should now be read correctly.
2194 The character tables have been updated to Unicode 3.2.0.
2198 Comparing with utf8 data does not magically upgrade non-utf8 data
2199 into utf8. (This was a problem for example if you were mixing data
2200 from I/O and Unicode data: your output might have got magically encoded
2205 Generating illegal Unicode code points like U+FFFE, or the UTF-16
2206 surrogates, now also generates an optional warning.
2210 C<IsAlnum>, C<IsAlpha>, and C<IsWord> now match titlecase.
2214 Concatenation with the C<.> operator or via variable interpolation,
2215 C<eq>, C<substr>, C<reverse>, C<quotemeta>, the C<x> operator,
2216 substitution with C<s///>, single-quoted UTF8, should now work.
2220 The C<tr///> operator now works. Note that the C<tr///CU>
2221 functionality has been removed (but see pack('U0', ...)).
2225 C<eval "v200"> now works.
2229 Perl 5.6.0 parsed m/\x{ab}/ incorrectly, leading to spurious warnings.
2230 This has been corrected.
2234 Zero entries were missing from the Unicode classes like C<IsDigit>.
2240 Large unsigned numbers (those above 2**31) could sometimes lose their
2241 unsignedness, causing bogus results in arithmetic operations.
2245 =head2 Platform Specific Changes and Fixes
2253 Perl now works on post-4.0 BSD/OSes.
2259 Setting C<$0> now works (as much as possible; see L<perlvar> for details).
2265 Numerous updates; currently synchronised with Cygwin 1.3.10.
2269 Previously DYNIX/ptx had problems in its Configure probe for non-blocking I/O.
2275 EPOC update after Perl 5.6.0. See README.epoc.
2281 Perl now works on post-3.0 FreeBSDs.
2287 README.hpux updated; C<Configure -Duse64bitall> now works.
2293 Numerous compilation flag and hint enhancements; accidental mixing
2294 of 32-bit and 64-bit libraries (a doomed attempt) made much harder.
2304 Long doubles should now work (see INSTALL).
2308 Linux previously had problems related to sockaddrlen when using
2309 accept(), revcfrom() (in Perl: recv()), getpeername(), and getsockname().
2317 Compilation of the standard Perl distribution in MacOS Classic should
2318 now work if you have the Metrowerks development environment and
2319 the missing Mac-specific toolkit bits. Contact the macperl mailing
2326 MPE/iX update after Perl 5.6.0. See README.mpeix.
2330 NetBSD/threads: try installing the GNU pth (should be in the
2331 packages collection, or http://www.gnu.org/software/pth/),
2332 and Configure with -Duseithreads.
2338 Perl now works on NetBSD/sparc.
2344 Now works with usethreads (see INSTALL).
2350 64-bitness using the Sun Workshop compiler now works.
2356 The native build method requires at least VOS Release 14.5.0
2357 and GNU C++/GNU Tools 2.0.1 or later. The Perl pack function
2358 now maps overflowed values to +infinity and underflowed values
2363 Tru64 (aka Digital UNIX, aka DEC OSF/1)
2365 The operating system version letter now recorded in $Config{osvers}.
2366 Allow compiling with gcc (previously explicitly forbidden). Compiling
2367 with gcc still not recommended because buggy code results, even with
2374 Fixed various alignment problems that lead into core dumps either
2375 during build or later; no longer dies on math errors at runtime;
2376 now using full quad integers (64 bits), previously was using
2377 only 46 bit integers for speed.
2383 chdir() now works better despite a CRT bug; now works with MULTIPLICITY
2384 (see INSTALL); now works with Perl's malloc.
2386 The tainting of C<%ENV> elements via C<keys> or C<values> was previously
2387 unimplemented. It now works as documented.
2389 The C<waitpid> emulation has been improved. The worst bug (now fixed)
2390 was that a pid of -1 would cause a wildcard search of all processes on
2391 the system. The most significant enhancement is that we can now
2392 usually get the completion status of a terminated process.
2394 POSIX-style signals are now emulated much better on VMS versions prior
2397 The C<system> function and backticks operator have improved
2398 functionality and better error handling.
2400 File access tests now use current process privileges rather than the
2401 user's default privileges, which could sometimes result in a mismatch
2402 between reported access and actual access.
2412 accept() no longer leaks memory.
2416 Borland C++ v5.5 is now a supported compiler that can build Perl.
2417 However, the generated binaries continue to be incompatible with those
2418 generated by the other supported compilers (GCC and Visual C++).
2422 Better chdir() return value for a non-existent directory.
2426 Duping socket handles with open(F, ">&MYSOCK") now works under Windows 9x.
2430 New %ENV entries now propagate to subprocesses.
2434 Current directory entries in %ENV are now correctly propagated to child
2439 $ENV{LIB} now used to search for libs under Visual C.
2443 fork() emulation has been improved in various ways, but still continues
2444 to be experimental. See L<perlfork> for known bugs and caveats.
2448 A failed (pseudo)fork now returns undef and sets errno to EAGAIN.
2452 Win32::GetCwd() correctly returns C:\ instead of C: when at the drive root.
2453 Other bugs in chdir() and Cwd::cwd() have also been fixed.
2457 HTML files will be installed in c:\perl\html instead of c:\perl\lib\pod\html
2461 The makefiles now provide a single switch to bulk-enable all the features
2462 enabled in ActiveState ActivePerl (a popular Win32 binary distribution).
2466 Allow REG_EXPAND_SZ keys in the registry.
2470 Can now send() from all threads, not just the first one.
2474 Fake signal handling reenabled, bugs and all.
2478 %SIG has been enabled under USE_ITHREADS, but its use is completely
2479 unsupported under all configurations.
2483 Less stack reserved per thread so that more threads can run
2484 concurrently. (Still 16M per thread.)
2488 C<File::Spec->tmpdir()> now prefers C:/temp over /tmp
2489 (works better when perl is running as service).
2493 Better UNC path handling under ithreads.
2497 wait(), waitpid() and backticks now return the correct exit status under
2502 winsock handle leak fixed.
2506 The Perl parser has been stress tested using both random input and
2507 Markov chain input and the few found crashes and lockups have been
2514 =head1 New or Changed Diagnostics
2520 The lexical warnings category "deprecated" is no longer a sub-category
2521 of the "syntax" category. It is now a top-level category in its own
2526 All regular expression compilation error messages are now hopefully
2527 easier to understand both because the error message now comes before
2528 the failed regex and because the point of failure is now clearly
2529 marked by a C<E<lt>-- HERE> marker.
2533 The various "opened only for", "on closed", "never opened" warnings
2534 drop the C<main::> prefix for filehandles in the C<main> package,
2535 for example C<STDIN> instead of C<main::STDIN>.
2539 The "Unrecognized escape" warning has been extended to include C<\8>,
2540 C<\9>, and C<\_>. There is no need to escape any of the C<\w> characters.
2544 Two new debugging options have been added: if you have compiled your
2545 Perl with debugging, you can use the -DT and -DR options to trace
2546 tokenising and to add reference counts to displaying variables,
2551 The debugger (perl5db.pl) has been modified to present a more
2552 consistent commands interface, via (CommandSet=580). perl5db.t was
2553 also added to test the changes, and as a placeholder for further tests.
2559 The debugger has a new C<dumpDepth> option to control the maximum
2560 depth to which nested structures are dumped. The C<x> command has
2561 been extended so that C<x N EXPR> dumps out the value of I<EXPR> to a
2562 depth of at most I<N> levels.
2566 The debugger can now show lexical variables if you have the CPAN
2567 module PadWalker installed.
2571 If an attempt to use a (non-blessed) reference as an array index
2572 is made, a warning is given.
2576 C<push @a;> and C<unshift @a;> (with no values to push or unshift)
2577 now give a warning. This may be a problem for generated and evaled
2582 If you try to L<perlfunc/pack> a number less than 0 or larger than 255
2583 using the C<"C"> format you will get an optional warning. Similarly
2584 for the C<"c"> format and a number less than -128 or more than 127.
2588 Certain regex modifiers such as C<(?o)> make sense only if applied to
2589 the entire regex. You will get an optional warning if you try to do
2594 Using arrays or hashes as references (e.g. C<< %foo->{bar} >>
2595 has been deprecated for a while. Now you will get an optional warning.
2599 Using C<sort> in scalar context now issues an optional warning.
2600 This didn't do anything useful, as the sort was not performed.
2604 =head1 Changed Internals
2610 perlapi.pod (a companion to perlguts) now attempts to document the
2615 You can now build a really minimal perl called microperl.
2616 Building microperl does not require even running Configure;
2617 C<make -f Makefile.micro> should be enough. Beware: microperl makes
2618 many assumptions, some of which may be too bold; the resulting
2619 executable may crash or otherwise misbehave in wondrous ways.
2620 For careful hackers only.
2624 Added rsignal(), whichsig(), do_join(), op_clear, op_null,
2625 ptr_table_clear(), ptr_table_free(), sv_setref_uv(), and several UTF-8
2626 interfaces to the publicised API. For the full list of the available
2627 APIs see L<perlapi>.
2631 Made possible to propagate customised exceptions via croak()ing.
2635 Now xsubs can have attributes just like subs. (Well, at least the
2636 built-in attributes.)
2640 dTHR and djSP have been obsoleted; the former removed (because it's
2641 a no-op) and the latter replaced with dSP.
2645 PERL_OBJECT has been completely removed.
2649 The MAGIC constants (e.g. C<'P'>) have been macrofied
2650 (e.g. C<PERL_MAGIC_TIED>) for better source code readability
2651 and maintainability.
2655 The regex compiler now maintains a structure that identifies nodes in
2656 the compiled bytecode with the corresponding syntactic features of the
2657 original regex expression. The information is attached to the new
2658 C<offsets> member of the C<struct regexp>. See L<perldebguts> for more
2659 complete information.
2663 The C code has been made much more C<gcc -Wall> clean. Some warning
2664 messages still remain in some platforms, so if you are compiling with
2665 gcc you may see some warnings about dubious practices. The warnings
2666 are being worked on.
2670 F<perly.c>, F<sv.c>, and F<sv.h> have now been extensively commented.
2674 Documentation on how to use the Perl source repository has been added
2675 to F<Porting/repository.pod>.
2679 There are now several profiling make targets.
2683 =head1 Security Vulnerability Closed
2685 (This change was already made in 5.7.0 but bears repeating here.)
2687 A potential security vulnerability in the optional suidperl component
2688 of Perl was identified in August 2000. suidperl is neither built nor
2689 installed by default. As of November 2001 the only known vulnerable
2690 platform is Linux, most likely all Linux distributions. CERT and
2691 various vendors and distributors have been alerted about the vulnerability.
2692 See http://www.cpan.org/src/5.0/sperl-2000-08-05/sperl-2000-08-05.txt
2693 for more information.
2695 The problem was caused by Perl trying to report a suspected security
2696 exploit attempt using an external program, /bin/mail. On Linux
2697 platforms the /bin/mail program had an undocumented feature which
2698 when combined with suidperl gave access to a root shell, resulting in
2699 a serious compromise instead of reporting the exploit attempt. If you
2700 don't have /bin/mail, or if you have 'safe setuid scripts', or if
2701 suidperl is not installed, you are safe.
2703 The exploit attempt reporting feature has been completely removed from
2704 Perl 5.8.0 (and the maintenance release 5.6.1, and it was removed also
2705 from all the Perl 5.7 releases), so that particular vulnerability
2706 isn't there anymore. However, further security vulnerabilities are,
2707 unfortunately, always possible. The suidperl functionality is most
2708 probably going to be removed in Perl 5.10. In any case, suidperl
2709 should only be used by security experts who know exactly what they are
2710 doing and why they are using suidperl instead of some other solution
2711 such as sudo ( see http://www.courtesan.com/sudo/ ).
2715 Several new tests have been added, especially for the F<lib>
2716 subsection. There are now about 56 000 individual tests (spread over
2717 about 620 test scripts), in the regression suite (5.6.1 has about
2718 11700 tests, in 258 test scripts) Many of the new tests are introduced
2719 by the new modules, but still in general Perl is now more thoroughly
2722 Because of the large number of tests, running the regression suite
2723 will take considerably longer time than it used to: expect the suite
2724 to take up to 4-5 times longer to run than in perl 5.6. In a really
2725 fast machine you can hope to finish the suite in about 6-8 minutes
2728 The tests are now reported in a different order than in earlier Perls.
2729 (This happens because the test scripts from under t/lib have been moved
2730 to be closer to the library/extension they are testing.)
2732 =head1 Known Problems
2740 In AIX 4.2 Perl extensions that use C++ functions that use statics
2741 may have problems in that the statics are not getting initialized.
2742 In newer AIX releases this has been solved by linking Perl with
2743 the libC_r library, but unfortunately in AIX 4.2 the said library
2744 has an obscure bug where the various functions related to time
2745 (such as time() and gettimeofday()) return broken values, and
2746 therefore in AIX 4.2 Perl is not linked against the libC_r.
2750 vac 5.0.0.0 May Produce Buggy Code For Perl
2752 The AIX C compiler vac version 5.0.0.0 may produce buggy code,
2753 resulting in few random tests failing, but when the failing tests
2754 are run by hand, they succeed. We suggest upgrading to at least
2755 vac version 5.0.1.0, that has been known to compile Perl correctly.
2756 "lslpp -L|grep vac.C" will tell you the vac version. See README.aix.
2760 If building threaded Perl, you may get compilation warning from pp_sys.c:
2762 "pp_sys.c", line 4651.39: 1506-280 (W) Function argument assignment between types "unsigned char*" and "const void*" is not allowed.
2764 This is harmless; it is caused by the getnetbyaddr() and getnetbyaddr_r()
2765 having slightly different types for their first argument.
2769 =head2 ext/threads/t/libc
2771 If this test fails, it indicates that your libc (C library) is not
2772 threadsafe. This particular test stress tests the localtime() call to
2773 find out whether it is threadsafe. See L<perlthrtut> for more information.
2775 =head2 FreeBSD Failing locale Test 117 For ISO8859-15 Locales
2777 The ISO8859-15 locales may fail the locale test 117 in FreeBSD.
2778 This is caused by the characters \xFF (y with diaeresis) and \xBE
2779 (Y with diaeresis) not behaving correctly when being matched
2782 =head2 Modifying $_ Inside for(..)
2786 works without complaint. It shouldn't. (You should be able to
2787 modify only lvalue elements inside the loops.) You can see the
2788 correct behaviour by replacing the 1..5 with 1, 2, 3, 4, 5.
2790 =head2 mod_perl 1.26 Doesn't Build With Threaded Perl
2792 Use mod_perl 1.27 or higher.
2794 =head2 lib/ftmp-security tests warn 'system possibly insecure'
2796 Don't panic. Read INSTALL 'make test' section instead.
2798 =head2 HP-UX lib/posix Subtest 9 Fails When LP64-Configured
2800 If perl is configured with -Duse64bitall, the successful result of the
2801 subtest 10 of lib/posix may arrive before the successful result of the
2802 subtest 9, which confuses the test harness so much that it thinks the
2805 =head2 Linux With Sfio Fails op/misc Test 48
2811 Please remember to set your environment variable LC_ALL to "C"
2812 (setenv LC_ALL C) before running "make test" to avoid a lot of
2813 warnings about the broken locales of Mac OS X.
2815 The following tests are known to fail:
2817 Failed Test Stat Wstat Total Fail Failed List of Failed
2818 -------------------------------------------------------------------------
2819 ../ext/DB_File/t/db-btree.t 0 11 ?? ?? % ??
2820 ../ext/DB_File/t/db-recno.t 149 3 2.01% 61 63 65
2822 If you are building on a UFS partition, you will also probably see
2823 t/op/stat.t subtest #9 fail. This is caused by Darwin's UFS not
2824 supporting inode change time.
2826 Also the ext/POSIX/t/posix.t subtest #10 fails but it is skipped for
2827 now because the failure is Apple's fault, not Perl's (blocked signals
2830 If you Configure with ithreads, ext/threads/t/libc.t will fail, again
2831 not Perl's fault-- the libc of Mac OS X is not threadsafe (in this
2832 particular test the localtime() call is found to be threadunsafe.)
2834 =head2 op/sprintf tests 91, 129, and 130
2836 The op/sprintf tests 91, 129, and 130 are known to fail on some platforms.
2837 Examples include any platform using sfio, and Compaq/Tandem's NonStop-UX.
2839 The test 91 is known to fail at QNX6 (nto), because C<sprintf '%e',0>
2840 incorrectly produces C<0.000000e+0> instead of C<0.000000e+00>.
2842 For the tests 129 and 130 the failing platforms do not comply with
2843 the ANSI C Standard, line 19ff on page 134 of ANSI X3.159 1989 to
2844 be exact. (They produce something other than "1" and "-1" when
2845 formatting 0.6 and -0.6 using the printf format "%.0f", most often
2846 they produce "0" and "-0".)
2850 In case you are still using Solaris 2.5 (aka SunOS 5.5), you may
2851 experience failures (the test core dumping) in lib/locale.t.
2852 The suggested cure is to upgrade your Solaris.
2856 When Perl is built using the native build process on VOS Release
2857 14.5.0 and GNU C++/GNU Tools 2.0.1, all attempted tests either
2858 pass or result in TODO (ignored) failures.
2860 =head Term::ReadKey not working on Win32
2862 Use Term::ReadKey 2.20 or later.
2864 =head2 Failure of Thread (5.005-style) tests
2866 B<Note that support for 5.005-style threading is deprecated,
2867 experimental and practically unsupported. In 5.10 it is expected
2870 The following tests are known to fail due to fundamental problems in
2871 the 5.005 threading implementation. These are not new failures--Perl
2872 5.005_0x has the same bugs, but didn't have these tests.
2874 ../ext/List/Util/t/first.t 255 65280 7 4 57.14% 2 5-7
2875 ../lib/English.t 2 512 54 2 3.70% 2-3
2876 ../lib/Filter/Simple/t/data.t 6 3 50.00% 1-3
2877 ../lib/Filter/Simple/t/filter_onl 9 3 33.33% 1-2 5
2878 ../lib/autouse.t 10 1 10.00% 4
2879 op/flip.t 15 1 6.67% 15
2881 These failures are unlikely to get fixed as the 5.005-style threads
2882 are considered fundamentally broken. (Basically what happens is that
2883 competing threads can corrupt shared global state.)
2887 Failed Test Stat Wstat Total Fail Failed List of Failed
2888 -------------------------------------------------------------------------
2889 ../lib/Math/Trig.t 26 1 3.85% 25
2890 ../lib/warnings.t 460 1 0.22% 425
2891 op/numconvert.t 1440 13 0.90% 208 509-510
2892 657-658 665-666 829-830 989-990 1149-1150
2894 The Trig and numconvert failures are caused by the slighly differing
2895 (from IEEE) floating point implementation of UNICOS. The warnings
2896 failure is also related: the test assumes a certain floating point
2897 output format, this assumption fails in UNICOS.
2905 During Configure the test
2907 Guessing which symbols your C compiler and preprocessor define...
2909 will probably fail with error messages like
2911 CC-20 cc: ERROR File = try.c, Line = 3
2912 The identifier "bad" is undefined.
2914 bad switch yylook 79bad switch yylook 79bad switch yylook 79bad switch yylook 79#ifdef A29K
2917 CC-65 cc: ERROR File = try.c, Line = 3
2918 A semicolon is expected at this point.
2920 This is caused by a bug in awk utility of UNICOS/mk. You can ignore
2921 the error, but it does cause a slight problem: you cannot fully
2922 benefit from the h2ph utility (see L<h2ph>) that can be used to
2923 convert C headers to Perl libraries, mainly used to be able to access
2924 from Perl the constants defined using C preprocessor, cpp. Because of
2925 the above error parts of the converted headers will be invisible.
2926 Luckily, these days the need for h2ph is rare.
2930 If building Perl with the interpreter threads (ithreads), the
2931 getgrent(), getgrnam(), and getgrgid() functions cannot return the
2932 list of the group members due to a bug in the multithreaded support of
2933 UNICOS/mk. What this means that in list context the functions will
2934 return only three values, not four.
2940 There are a few known test failures, see L<perluts>.
2944 There should be no reported test failures with a default configuration,
2945 though there are a number of tests marked TODO that point to areas
2946 needing further debugging and/or porting work.
2950 In multi-CPU boxes there are some problems with the I/O buffering:
2951 some output may appear twice.
2953 =head2 XML::Parser not working
2955 Use XML::Parser 2.31 or later.
2957 =head2 z/OS (OS/390)
2959 z/OS has rather many test failures but the situation is actually
2960 better than it was in 5.6.0, it's just that so many new modules and
2961 tests have been added.
2963 Failed Test Stat Wstat Total Fail Failed List of Failed
2964 ---------------------------------------------------------------------------
2965 ../ext/Data/Dumper/t/dumper.t 357 8 2.24% 311 314 325 327
2967 ../ext/IO/lib/IO/t/io_unix.t 5 4 80.00% 2-5
2968 ../ext/Storable/t/downgrade.t 12 3072 169 12 7.10% 14-15 46-47 78-79
2970 ../lib/ExtUtils/t/Constant.t 121 30976 48 48 100.00% 1-48
2971 ../lib/ExtUtils/t/Embed.t 9 9 100.00% 1-9
2972 op/pat.t 910 7 0.77% 665 776 785 832-
2974 op/sprintf.t 224 3 1.34% 98 100 136
2975 op/tr.t 97 5 5.15% 63 71-74
2976 uni/fold.t 780 6 0.77% 61 169 196 661
2979 The dumper.t and downgrade.t are problems in the tests, the io_unix
2980 and sprintf are problems in the USS (UDP sockets and printf formats).
2981 The pat, tr, and fold are genuine Perl problems caused by EBCDIC (and
2982 in the pat and fold cases, combining that with Unicode). The Constant
2983 and Embed are probably problems in the tests (since they test Perl's
2984 ability to build extensions, and that seems to be working reasonably well.)
2986 =head2 Localising Tied Arrays and Hashes Is Broken
2990 doesn't work as one would expect: the old value is restored
2993 =head2 Self-tying of Arrays and Hashes Is Forbidden
2995 Self-tying of arrays and hashes is broken in rather deep and
2996 hard-to-fix ways. As a stop-gap measure to avoid people from getting
2997 frustrated at the mysterious results (core dumps, most often) it is
2998 for now forbidden (you will get a fatal error even from an attempt).
3000 =head2 Building Extensions Can Fail Because Of Largefiles
3002 Some extensions like mod_perl are known to have issues with
3003 `largefiles', a change brought by Perl 5.6.0 in which file offsets
3004 default to 64 bits wide, where supported. Modules may fail to compile
3005 at all or compile and work incorrectly. Currently there is no good
3006 solution for the problem, but Configure now provides appropriate
3007 non-largefile ccflags, ldflags, libswanted, and libs in the %Config
3008 hash (e.g., $Config{ccflags_nolargefiles}) so the extensions that are
3009 having problems can try configuring themselves without the
3010 largefileness. This is admittedly not a clean solution, and the
3011 solution may not even work at all. One potential failure is whether
3012 one can (or, if one can, whether it's a good idea) link together at
3013 all binaries with different ideas about file offsets, all this is
3016 =head2 Unicode Support on EBCDIC Still Spotty
3018 Though mostly working, Unicode support still has problem spots on
3019 EBCDIC platforms. One such known spot are the C<\p{}> and C<\P{}>
3020 regular expression constructs for code points less than 256: the
3021 C<pP> are testing for Unicode code points, not knowing about EBCDIC.
3023 =head2 The Compiler Suite Is Still Very Experimental
3025 The compiler suite is slowly getting better but it continues to be
3026 highly experimental. Use in production environments is discouraged.
3028 =head2 The Long Double Support Is Still Experimental
3030 The ability to configure Perl's numbers to use "long doubles",
3031 floating point numbers of hopefully better accuracy, is still
3032 experimental. The implementations of long doubles are not yet
3033 widespread and the existing implementations are not quite mature
3034 or standardised, therefore trying to support them is a rare
3035 and moving target. The gain of more precision may also be offset
3036 by slowdown in computations (more bits to move around, and the
3037 operations are more likely to be executed by less optimised
3040 =head2 Seen In Perl 5.7 But Gone Now
3042 C<Time::Piece> (previously known as C<Time::Object>) was removed
3043 because it was felt that it didn't have enough value in it to be a
3044 core module. It is still a useful module, though, and is available
3047 Perl 5.8 unfortunately does not build anymore on AmigaOS,
3048 this broke at some point accidentally. Since there are not that many
3049 Amiga developers available, we could not get this fixed and tested in
3052 =head1 Reporting Bugs
3054 If you find what you think is a bug, you might check the articles
3055 recently posted to the comp.lang.perl.misc newsgroup and the perl
3056 bug database at http://bugs.perl.org/ There may also be
3057 information at http://www.perl.com/ , the Perl Home Page.
3059 If you believe you have an unreported bug, please run the B<perlbug>
3060 program included with your release. Be sure to trim your bug down
3061 to a tiny but sufficient test case. Your bug report, along with the
3062 output of C<perl -V>, will be sent off to perlbug@perl.org to be
3063 analysed by the Perl porting team.
3067 The F<Changes> file for exhaustive details on what changed.
3069 The F<INSTALL> file for how to build Perl.
3071 The F<README> file for general stuff.
3073 The F<Artistic> and F<Copying> files for copyright information.
3077 Written by Jarkko Hietaniemi <F<jhi@iki.fi>>.