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.
324 =head2 Restricted Hashes
326 A restricted hash is restricted to a certain set of keys, no keys
327 outside the set can be added. Also individual keys can be restricted
328 so that the key cannot be deleted and the value cannot be changed.
329 No new syntax is involved: the Hash::Util module is the interface.
333 Perl used to be fragile in that signals arriving at inopportune moments
334 could corrupt Perl's internal state. Now Perl postpones handling of
335 signals until it's safe (between opcodes).
337 This change may have surprising side effects because signals no longer
338 interrupt Perl instantly. Perl will now first finish whatever it was
339 doing, like finishing an internal operation (like sort()) or an
340 external operation (like an I/O operation), and only then look at any
341 arrived signals (and before starting the next operation). No more corrupt
342 internal state since the current operation is always finished first,
343 but the signal may take more time to get heard. Note that breaking
344 out from potentially blocking operations should still work, though.
346 =head2 Unicode Overhaul
348 Unicode in general should be now much more usable than in Perl 5.6.0
349 (or even in 5.6.1). Unicode can be used in hash keys, Unicode in
350 regular expressions should work now, Unicode in tr/// should work now,
351 Unicode in I/O should work now. See L<perluniintro> for introduction
352 and L<perlunicode> for details.
358 The Unicode Character Database coming with Perl has been upgraded
359 to Unicode 3.2.0. For more information, see http://www.unicode.org/ .
363 For developers interested in enhancing Perl's Unicode capabilities:
364 almost all the UCD files are included with the Perl distribution in
365 the F<lib/unicore subdirectory>. The most notable omission, for space
366 considerations, is the Unihan database.
370 The properties \p{Blank} and \p{SpacePerl} have been added. "Blank" is like
371 C isblank(), that is, it contains only "horizontal whitespace" (the space
372 character is, the newline isn't), and the "SpacePerl" is the Unicode
373 equivalent of C<\s> (\p{Space} isn't, since that includes the vertical
374 tabulator character, whereas C<\s> doesn't.)
376 See "New Unicode Properties" earlier in this document for additional
377 information on changes with Unicode properties.
381 =head2 Understanding of Numbers
383 In general a lot of fixing has happened in the area of Perl's
384 understanding of numbers, both integer and floating point. Since in
385 many systems the standard number parsing functions like C<strtoul()>
386 and C<atof()> seem to have bugs, Perl tries to work around their
387 deficiencies. This results hopefully in more accurate numbers.
389 Perl now tries internally to use integer values in numeric conversions
390 and basic arithmetics (+ - * /) if the arguments are integers, and
391 tries also to keep the results stored internally as integers.
392 This change leads to often slightly faster and always less lossy
393 arithmetics. (Previously Perl always preferred floating point numbers
396 =head2 Miscellaneous Changes
402 AUTOLOAD is now lvaluable, meaning that you can add the :lvalue attribute
403 to AUTOLOAD subroutines and you can assign to the AUTOLOAD return value.
407 C<perl -d:Module=arg,arg,arg> now works (previously one couldn't pass
408 in multiple arguments.)
412 The builtin dump() now gives an optional warning
413 C<dump() better written as CORE::dump()>,
414 meaning that by default C<dump(...)> is resolved as the builtin
415 dump() which dumps core and aborts, not as (possibly) user-defined
416 C<sub dump>. To call the latter, qualify the call as C<&dump(...)>.
417 (The whole dump() feature is to considered deprecated, and possibly
418 removed/changed in future releases.)
422 chomp() and chop() are now overridable. Note, however, that their
423 prototype (as given by C<prototype("CORE::chomp")> is undefined,
424 because it cannot be expressed and therefore one cannot really write
425 replacements to override these builtins.
429 END blocks are now run even if you exit/die in a BEGIN block.
430 Internally, the execution of END blocks is now controlled by
431 PL_exit_flags & PERL_EXIT_DESTRUCT_END. This enables the new
432 behaviour for Perl embedders. This will default in 5.10. See
437 Formats now support zero-padded decimal fields.
441 Lvalue subroutines can now return C<undef> in list context.
442 However, the lvalue subroutine feature still remains experimental.
446 A lost warning "Can't declare ... dereference in my" has been
447 restored (Perl had it earlier but it became lost in later releases.)
451 A new special regular expression variable has been introduced:
452 C<$^N>, which contains the most-recently closed group (submatch).
456 C<no Module;> now works even if there is no "sub unimport" in the Module.
460 The numerical comparison operators return C<undef> if either operand
461 is a NaN. Previously the behaviour was unspecified.
465 The following builtin functions are now overridable: each(), keys(),
466 pop(), push(), shift(), splice(), unshift().
470 C<pack() / unpack()> now can group template letters with C<()> and then
471 apply repetition/count modifiers on the groups.
475 C<pack() / unpack()> can now process the Perl internal numeric types:
476 IVs, UVs, NVs-- and also long doubles, if supported by the platform.
477 The template letters are C<j>, C<J>, C<F>, and C<D>.
481 C<pack('U0a*', ...)> can now be used to force a string to UTF8.
485 my __PACKAGE__ $obj now works.
489 The printf() and sprintf() now support parameter reordering using the
490 C<%\d+\$> and C<*\d+\$> syntaxes. For example
492 print "%2\$s %1\$s\n", "foo", "bar";
494 will print "bar foo\n". This feature helps in writing
495 internationalised software, and in general when the order
496 of the parameters can vary.
500 prototype(\&) is now available.
504 prototype(\[$@%&]) is now available to implicitly create references
505 (useful for example if you want to emulate the tie() interface).
509 A new command-line option, C<-t> is available. It is the
510 little brother of C<-T>: instead of dying on taint violations,
511 lexical warnings are given. B<This is only meant as a temporary
512 debugging aid while securing the code of old legacy applications.
513 This is not a substitute for -T.>
517 In other taint news, the C<exec LIST> and C<system LIST> have now been
518 considered too risky (think C<exec @ARGV>: it can start any program
519 with any arguments), and now the said forms cause a warning.
520 You should carefully launder the arguments to guarantee their
521 validity. In future releases of Perl the forms will become fatal
522 errors so consider starting laundering now.
526 If tr/// is just counting characters, it doesn't attempt to
531 untie() will now call an UNTIE() hook if it exists. See L<perltie>
536 L<utime> now supports C<utime undef, undef, @files> to change the
537 file timestamps to the current time.
541 The rules for allowing underscores (underbars) in numeric constants
542 have been relaxed and simplified: now you can have an underscore
543 simply B<between digits>.
547 Rather than relying on C's argv[0] (which may not contain a full pathname)
548 where possible $^X is now set by asking the operating system.
549 (eg by reading F</proc/self/exe> on Linux, F</proc/curproc/file> on FreeBSD)
553 A new variable, C<${^TAINT}>, indicates whether taint mode is enabled.
557 You can now override the readline() builtin, and this overrides also
558 the <FILEHANDLE> angle bracket operator.
562 The command-line options -s and -F are now recognized on the shebang
567 Use of the C</c> match modifier without an accompanying C</g> modifier
568 elicits a new warning: C<Use of /c modifier is meaningless without /g>.
570 Use of C</c> in substitutions, even with C</g>, elicits
571 C<Use of /c modifier is meaningless in s///>.
573 Use of C</g> with C<split> elicits C<Use of /g modifier is meaningless
578 =head1 Modules and Pragmata
580 =head2 New Modules and Pragmata
586 C<Attribute::Handlers> allows a class to define attribute handlers.
589 use Attribute::Handlers;
590 sub Wolf :ATTR(SCALAR) { print "howl!\n" }
592 # later, in some package using or inheriting from MyPack...
594 my MyPack $Fluffy : Wolf; # the attribute handler Wolf will be called
596 Both variables and routines can have attribute handlers. Handlers can
597 be specific to type (SCALAR, ARRAY, HASH, or CODE), or specific to the
598 exact compilation phase (BEGIN, CHECK, INIT, or END).
602 B<B::Concise> is a new compiler backend for walking the Perl syntax
603 tree, printing concise info about ops, from Stephen McCamant. The
604 output is highly customisable. See L<B::Concise>.
608 The new bignum, bigint, and bigrat pragmas implement transparent
609 bignum support (using the Math::BigInt, Math::BigFloat, and
610 Math::BigRat backends), by Tels.
614 C<Class::ISA> for reporting the search path for a class's ISA tree,
615 by Sean Burke, has been added. See L<Class::ISA>.
619 C<Cwd> has now a split personality: if possible, an XS extension is
620 used, (this will hopefully be faster, more secure, and more robust)
621 but if not possible, the familiar Perl implementation is used.
625 C<Devel::PPPort>, originally from Kenneth Albanowski and now
626 maintained by Paul Marquess, has been added. It is primarily used
627 by C<h2xs> to enhance portability of XS modules between different
632 C<Digest>, frontend module for calculating digests (checksums), from
633 Gisle Aas, has been added. See L<Digest>.
637 C<Digest::MD5> for calculating MD5 digests (checksums) as defined in
638 RFC 1321, from Gisle Aas, has been added. See L<Digest::MD5>.
640 use Digest::MD5 'md5_hex';
642 $digest = md5_hex("Thirsty Camel");
644 print $digest, "\n"; # 01d19d9d2045e005c3f1b80e8b164de1
646 NOTE: the C<MD5> backward compatibility module is deliberately not
647 included since its further use is discouraged.
651 C<Encode>, orginally by Nick Ing-Simmons and now maintained by Dan
652 Kogai, provides a mechanism to translate between different character
653 encodings. Support for Unicode, ISO-8859-1, and ASCII are compiled in
654 to the module. Several other encodings (like the rest of the
655 ISO-8859, CP*/Win*, Mac, KOI8-R, three variants EBCDIC, Chinese,
656 Japanese, and Korean encodings) are included and can be loaded at
657 runtime. (For space considerations, the largest Chinese encodings
658 have been separated into their own CPAN module, Encode::HanExtra,
659 which Encode will use if available). See L<Encode>.
661 Any encoding supported by Encode module is also available to the
662 ":encoding()" layer if PerlIO is used.
666 C<Hash::Util> is the interface to the new I<restricted hashes>
667 feature. (Implemented by Jeffrey Friedl, Nick Ing-Simmons, and
672 C<I18N::Langinfo> can be use to query locale information.
673 See L<I18N::Langinfo>.
677 C<I18N::LangTags> has functions for dealing with RFC3066-style
678 language tags, by Sean Burke. See L<I18N::LangTags>.
682 C<ExtUtils::Constant> is a new tool for extension writers for
683 generating XS code to import C header constants, by Nicholas Clark.
684 See L<ExtUtils::Constant>.
688 C<Filter::Simple> is an easy-to-use frontend to Filter::Util::Call,
689 from Damian Conway. See L<Filter::Simple>.
695 use Filter::Simple sub {
696 while (my ($from, $to) = splice @_, 0, 2) {
705 use MyFilter qr/red/ => 'green';
707 print "red\n"; # this code is filtered, will print "green\n"
708 print "bored\n"; # this code is filtered, will print "bogreen\n"
712 print "red\n"; # this code is not filtered, will print "red\n"
716 C<File::Temp> allows one to create temporary files and directories in
717 an easy, portable, and secure way, by Tim Jenness. See L<File::Temp>.
721 C<Filter::Util::Call> provides you with the framework to write
722 I<Source Filters> in Perl, from Paul Marquess. For most uses the
723 frontend Filter::Simple is to be preferred. See L<Filter::Util::Call>.
727 C<if> is a new pragma for conditional inclusion of modules, from
732 L<libnet> is a collection of perl5 modules related to network
733 programming, from Graham Barr. See L<Net::FTP>, L<Net::NNTP>,
734 L<Net::Ping> (not part of libnet, but related), L<Net::POP3>,
735 L<Net::SMTP>, and L<Net::Time>.
737 Perl installation leaves libnet unconfigured, use F<libnetcfg> to configure.
741 C<List::Util> is a selection of general-utility list subroutines, like
742 sum(), min(), first(), and shuffle(), by Graham Barr. See L<List::Util>.
746 C<Locale::Constants>, C<Locale::Country>, C<Locale::Currency>
747 C<Locale::Language>, and L<Locale::Script>, from Neil Bowers, have
748 been added. They provide the codes for various locale standards, such
749 as "fr" for France, "usd" for US Dollar, and "ja" for Japanese.
753 $country = code2country('jp'); # $country gets 'Japan'
754 $code = country2code('Norway'); # $code gets 'no'
756 See L<Locale::Constants>, L<Locale::Country>, L<Locale::Currency>,
757 and L<Locale::Language>.
761 C<Locale::Maketext> is localization framework from Sean Burke. See
762 L<Locale::Maketext>, and L<Locale::Maketext::TPJ13>. The latter is an
763 article about software localization, originally published in The Perl
764 Journal #13, republished here with kind permission.
768 C<Math::BigRat> for big rational numbers, to accompany Math::BigInt and
769 Math::BigFloat, from Tels.
773 C<Memoize> can make your functions faster by trading space for time,
774 from Mark-Jason Dominus. See L<Memoize>.
778 C<MIME::Base64> allows you to encode data in base64, from Gisle Aas,
779 as defined in RFC 2045 - I<MIME (Multipurpose Internet Mail
784 $encoded = encode_base64('Aladdin:open sesame');
785 $decoded = decode_base64($encoded);
787 print $encoded, "\n"; # "QWxhZGRpbjpvcGVuIHNlc2FtZQ=="
793 C<MIME::QuotedPrint> allows you to encode data in quoted-printable
794 encoding, as defined in RFC 2045 - I<MIME (Multipurpose Internet Mail
795 Extensions)>, from Gisle Aas.
797 use MIME::QuotedPrint;
799 $encoded = encode_qp("Smiley in Unicode: \x{263a}");
800 $decoded = decode_qp($encoded);
802 print $encoded, "\n"; # "Smiley in Unicode: =263A"
804 MIME::QuotedPrint has been enhanced to provide the basic methods
805 necessary to use it with PerlIO::Via as in :
807 use MIME::QuotedPrint;
808 open($fh,">Via(MIME::QuotedPrint)",$path);
810 See L<MIME::QuotedPrint>.
814 C<NEXT> is pseudo-class for method redispatch, from Damian Conway.
819 C<open> is a new pragma for setting the default I/O disciplines
824 C<PerlIO::Scalar> provides the implementation of IO to "in memory"
825 Perl scalars as discussed above, from Nick Ing-Simmons. It also
826 serves as an example of a loadable PerlIO layer. Other future
827 possibilities include PerlIO::Array and PerlIO::Code.
828 See L<PerlIO::Scalar>.
832 C<PerlIO::Via> acts as a PerlIO layer and wraps PerlIO layer
833 functionality provided by a class (typically implemented in perl
834 code), from Nick Ing-Simmons.
836 use MIME::QuotedPrint;
837 open($fh,">Via(MIME::QuotedPrint)",$path);
839 This will automatically convert everything output to C<$fh>
840 to Quoted-Printable. See L<PerlIO::Via>.
844 C<Pod::ParseLink>, by Russ Allbery, has been added,
845 to parse LZ<><> links in pods as described in the new
850 C<Pod::Text::Overstrike>, by Joe Smith, has been added.
851 It converts POD data to formatted overstrike text.
852 See L<Pod::Text::Overstrike>.
856 C<Scalar::Util> is a selection of general-utility scalar subroutines,
857 like blessed(), reftype(), and tainted(). See L<Scalar::Util>.
861 C<sort> is a new pragma for controlling the behaviour of sort().
865 C<Storable> gives persistence to Perl data structures by allowing the
866 storage and retrieval of Perl data to and from files in a fast and
867 compact binary format, from Raphael Manfredi. See L<Storable>.
871 C<Switch>, from Damian Conway, has been added. Just by saying
875 you have C<switch> and C<case> available in Perl.
881 case 1 { print "number 1" }
882 case "a" { print "string a" }
883 case [1..10,42] { print "number in list" }
884 case (@array) { print "number in list" }
885 case /\w+/ { print "pattern" }
886 case qr/\w+/ { print "pattern" }
887 case (%hash) { print "entry in hash" }
888 case (\%hash) { print "entry in hash" }
889 case (\&sub) { print "arg to subroutine" }
890 else { print "previous case not true" }
897 C<Test::More> is yet another framework for writing test scripts,
898 more extensive than Test::Simple, by Michael Schwern. See L<Test::More>.
902 C<Test::Simple> has basic utilities for writing tests, by Michael
903 Schwern. See L<Test::Simple>.
907 C<Text::Balanced> has been added, for extracting delimited text
908 sequences from strings, from Damian Conway.
910 use Text::Balanced 'extract_delimited';
912 ($a, $b) = extract_delimited("'never say never', he never said", "'", '');
914 $a will be "'never say never'", $b will be ', he never said'.
916 In addition to extract_delimited() there are also extract_bracketed(),
917 extract_quotelike(), extract_codeblock(), extract_variable(),
918 extract_tagged(), extract_multiple(), gen_delimited_pat(), and
919 gen_extract_tagged(). With these you can implement rather advanced
920 parsing algorithms. See L<Text::Balanced>.
924 C<threads> is an interface to interpreter threads, by Arthur Bergman.
925 Interpreter threads (ithreads) is the new thread model introduced in
926 Perl 5.6 but only available as an internal interface for extension
927 writers (and for Win32 Perl for C<fork()> emulation). See L<threads>.
931 C<threads::shared> allows data sharing for interpreter threads, from
932 Arthur Bergman. In the ithreads model any data sharing between
933 threads must be explicit, as opposed to the old 5.005 thread model
934 where data sharing was implicit. See L<threads::shared>.
938 C<Tie::File>, by Mark-Jason Dominus, associates a Perl array with the
943 C<Tie::Memoize>, by Ilya Zakharevich, provides on-demand loaded hashes.
947 C<Tie::RefHash::Nestable>, by Edward Avis, allows storing hash
948 references (unlike the standard Tie::RefHash) The module is contained
949 within Tie::RefHash, see L<Tie::RefHash>.
953 C<Time::HiRes> provides high resolution timing (ualarm, usleep,
954 and gettimeofday), from Douglas E. Wegscheid. See L<Time::HiRes>.
958 C<Unicode::UCD> offers a querying interface to the Unicode Character
959 Database. See L<Unicode::UCD>.
963 C<Unicode::Collate> implements the UCA (Unicode Collation Algorithm)
964 for sorting Unicode strings, by SADAHIRO Tomoyuki. See L<Unicode::Collate>.
968 C<Unicode::Normalize> implements the various Unicode normalization
969 forms, by SADAHIRO Tomoyuki. See L<Unicode::Normalize>.
973 C<XS::Typemap>, by Tim Jenness, is a test extension that exercises XS
974 typemaps. Nothing gets installed but for extension writers the code
979 =head2 Updated And Improved Modules and Pragmata
985 The following independently supported modules have been updated to the
986 newest versions from CPAN: CGI, CPAN, DB_File, File::Spec, File::Temp,
987 Getopt::Long, Math::BigFloat, Math::BigInt, the podlators bundle
988 (Pod::Man, Pod::Text), Pod::LaTeX, Pod::Parser, Storable,
989 Term::ANSIColor, Test, Text-Tabs+Wrap.
993 The attributes::reftype() now works on tied arguments.
997 AutoLoader can now be disabled with C<no AutoLoader;>.
1001 B::Deparse has been significantly enhanced. It now can deparse almost
1002 all of the standard test suite (so that the tests still succeed).
1003 There is a make target "test.deparse" for trying this out.
1007 Class::Struct can now define the classes in compile time.
1011 Class::Struct now assigns the array/hash element if the accessor
1012 is called with an array/hash element as the B<sole> argument.
1016 Data::Dumper has now an option to sort hashes.
1020 Data::Dumper has now an option to dump code references
1025 DB_File now supports newer Berkeley DB versions, among
1030 The English module can now be used without the infamous performance
1033 use English '-no_match_vars';
1035 (Assuming, of course, that one doesn't need the troublesome variables
1036 C<$`>, C<$&>, or C<$'>.) Also, introduced C<@LAST_MATCH_START> and
1037 C<@LAST_MATCH_END> English aliases for C<@-> and C<@+>.
1041 Fcntl, Socket, and Sys::Syslog have been rewritten to use the
1042 new-style constant dispatch section (see L<ExtUtils::Constant>).
1043 This means that they will be more robust and hopefully faster.
1047 File::Find now chdir()s correctly when chasing symbolic links.
1051 File::Find now has pre- and post-processing callbacks. It also
1052 correctly changes directories when chasing symbolic links. Callbacks
1053 (naughtily) exiting with "next;" instead of "return;" now work.
1057 File::Find is now (again) reentrant. It also has been made
1062 The warnings issued by File::Find now belong to their own category.
1063 You can enable/disable them with C<use/no warnings 'File::Find';>.
1067 File::Glob::glob() renamed to File::Glob::bsd_glob() to avoid
1068 prototype mismatch with CORE::glob().
1072 File::Glob now supports C<GLOB_LIMIT> constant to limit the size of
1073 the returned list of filenames.
1077 Devel::Peek now has an interface for the Perl memory statistics
1078 (this works only if you are using perl's malloc, and if you have
1079 compiled with debugging).
1083 IPC::Open3 now allows the use of numeric file descriptors.
1087 IO::Socket has now atmark() method, which returns true if the socket
1088 is positioned at the out-of-band mark. The method is also exportable
1089 as a sockatmark() function.
1093 IO::Socket::INET has support for ReusePort option (if your platform
1094 supports it). The Reuse option now has an alias, ReuseAddr. For clarity
1095 you may want to prefer ReuseAddr.
1099 IO::Socket::INET now supports C<LocalPort> of zero (usually meaning
1100 that the operating system will make one up.)
1104 use lib now works identically to @INC. Removing directories
1105 with 'no lib' now works.
1109 ExtUtils::MakeMaker now uses File::Spec internally, which hopefully
1110 leads into better portability.
1114 Math::BigFloat and Math::BigInt have undergone a full rewrite.
1115 They are now magnitudes faster, and they support various
1116 bignum libraries such as GMP and PARI as their backends.
1120 Math::Complex handles inf, NaN etc., better.
1124 Net::Ping has been muchly enhanced: multihoming is now supported,
1125 Win32 functionality is better, there is now time measuring
1126 functionality (optionally high-resolution using Time::HiRes),
1127 and there is now "external" protocol which uses Net::Ping::External
1128 module which runs your external ping utility and parses the output.
1129 A version of Net::Ping::External is available in CPAN.
1131 Note that some of the Net::Ping tests are disabled when running
1132 under the Perl distribution since one cannot assume one or more
1133 of the following: enabled echo port at localhost, full Internet
1134 connectivity, or sympathetic firewalls. You can set the environment
1135 variable PERL_TEST_Net_Ping to "1" (one) before running the Perl test
1136 suite to enable all the Net::Ping tests.
1140 POSIX::sigaction() is now much more flexible and robust.
1141 You can now install coderef handlers, 'DEFAULT', and 'IGNORE'
1142 handlers, installing new handlers was not atomic.
1146 In Safe the C<%INC> now localised in a Safe compartment so that
1151 In SDBM_File on dosish platforms, some keys went missing because of
1152 lack of support for files with "holes". A workaround for the problem
1157 In Search::Dict one can now have a pre-processing hook for the
1158 lines being searched.
1162 The Shell module now has an OO interface.
1166 In Sys::Syslog there is now a failover mechanism that will go
1167 through alternative connection mechanisms until the message
1168 is successfully logged.
1172 The Test module has been significantly enhanced.
1176 Time::Local::timelocal() does not handle fractional seconds anymore.
1177 The rationale is that neither does localtime(), and timelocal() and
1178 localtime() are supposed to be inverses of each other.
1182 The vars pragma now supports declaring fully qualified variables.
1183 (Something that C<our()> does not and will not support.)
1187 The C<utf8::> name space (as in the pragma) provides various
1188 Perl-callable functions to provide low level access to Perl's
1189 internal Unicode representation. At the moment only length()
1190 has been implemented.
1194 =head1 Utility Changes
1200 Emacs perl mode (emacs/cperl-mode.el) has been updated to version
1205 F<emacs/e2ctags.pl> is now much faster.
1209 C<enc2xs> is a tool for people adding their own encodings to the
1214 C<h2ph> now supports C trigraphs.
1218 C<h2xs> now produces a template README.
1222 C<h2xs> now uses C<Devel::PPort> for better portability between
1223 different versions of Perl.
1227 C<h2xs> uses the new L<ExtUtils::Constant> module which will affect
1228 newly created extensions that define constants. Since the new code is
1229 more correct (if you have two constants where the first one is a
1230 prefix of the second one, the first constant B<never> gets defined),
1231 less lossy (it uses integers for integer constant, as opposed to the
1232 old code that used floating point numbers even for integer constants),
1233 and slightly faster, you might want to consider regenerating your
1234 extension code (the new scheme makes regenerating easy).
1235 L<h2xs> now also supports C trigraphs.
1239 C<libnetcfg> has been added to configure the libnet.
1243 C<perlbug> is now much more robust. It also sends the bug report to
1244 perl.org, not perl.com.
1248 C<perlcc> has been rewritten and its user interface (that is,
1249 command line) is much more like that of the UNIX C compiler, cc.
1250 (The perlbc tools has been removed. Use C<perlcc -B> instead.)
1254 C<perlivp> is a new Installation Verification Procedure utility
1255 for running any time after installing Perl.
1259 C<piconv> is an implementation of the character conversion utility
1260 C<iconv>, demonstrating the new Encode module.
1264 C<pod2html> now allows specifying a cache directory.
1268 C<pod2html> now produces XHTML 1.0.
1272 C<pod2html> now understands POD written using different line endings
1273 (PC-like CRLF versus UNIX-like LF versus MacClassic-like CR).
1277 C<s2p> has been completely rewritten in Perl. (It is in fact a full
1278 implementation of sed in Perl: you can use the sed functionality by
1279 using the C<psed> utility.)
1283 C<xsubpp> now understands POD documentation embedded in the *.xs files.
1287 C<xsubpp> now supports OUT keyword.
1291 =head1 New Documentation
1297 perl56delta details the changes between the 5.005 release and the
1302 perlclib documents the internal replacements for standard C library
1303 functions. (Interesting only for extension writers and Perl core
1308 perldebtut is a Perl debugging tutorial.
1312 perlebcdic contains considerations for running Perl on EBCDIC platforms.
1316 perlintro is a gentle introduction to Perl.
1320 perliol documents the internals of PerlIO with layers.
1324 perlmodstyle is a style guide for writing modules.
1328 perlnewmod tells about writing and submitting a new module.
1332 perlpacktut is a pack() tutorial.
1336 perlpod has been rewritten to be clearer and to record the best
1337 practices gathered over the years.
1341 perlpodspec is a more formal specification of the pod format,
1342 mainly of interest for writers of pod applications, not to
1343 people writing in pod.
1347 perlretut is a regular expression tutorial.
1351 perlrequick is a regular expressions quick-start guide.
1352 Yes, much quicker than perlretut.
1356 perltodo has been updated.
1360 perltootc has been renamed as perltooc (to not to conflict
1361 with perltoot in filesystems restricted to "8.3" names)
1365 perluniintro is an introduction to using Unicode in Perl.
1366 (perlunicode is more of a detailed reference and background
1371 perlutil explains the command line utilities packaged with the Perl
1376 The following platform-specific documents are available before
1377 the installation as README.I<platform>, and after the installation
1380 perlaix perlamiga perlapollo perlbeos perlbs2000
1381 perlce perlcygwin perldgux perldos perlepoc perlhpux
1382 perlhurd perlmachten perlmacos perlmint perlmpeix
1383 perlnetware perlos2 perlos390 perlplan9 perlqnx perlsolaris
1384 perltru64 perluts perlvmesa perlvms perlvos perlwin32
1390 The documentation for the POSIX-BC platform is called "BS2000", to avoid
1391 confusion with the Perl POSIX module.
1395 The documentation for the WinCE platform is called perlce (README.ce
1396 in the source code kit), to avoid confusion with the perlwin32
1397 documentation on 8.3-restricted filesystems.
1401 =head1 Performance Enhancements
1407 map() could get pathologically slow when the result list it generates
1408 is larger than the source list. The performance has been improved for
1413 sort() has been changed to use primarily mergesort internally as
1414 opposed to the earlier quicksort. For very small lists this may
1415 result in slightly slower sorting times, but in general the speedup
1416 should be at least 20%. Additional bonuses are that the worst case
1417 behaviour of sort() is now better (in computer science terms it now
1418 runs in time O(N log N), as opposed to quicksort's Theta(N**2)
1419 worst-case run time behaviour), and that sort() is now stable
1420 (meaning that elements with identical keys will stay ordered as they
1421 were before the sort). See the C<sort> pragma for information.
1423 The story in more detail: suppose you want to serve yourself a little
1426 @digits = ( 3,1,4,1,5,9 );
1428 A numerical sort of the digits will yield (1,1,3,4,5,9), as expected.
1429 Which C<1> comes first is hard to know, since one C<1> looks pretty
1430 much like any other. You can regard this as totally trivial,
1431 or somewhat profound. However, if you just want to sort the even
1432 digits ahead of the odd ones, then what will
1434 sort { ($a % 2) <=> ($b % 2) } @digits;
1436 yield? The only even digit, C<4>, will come first. But how about
1437 the odd numbers, which all compare equal? With the quicksort algorithm
1438 used to implement Perl 5.6 and earlier, the order of ties is left up
1439 to the sort. So, as you add more and more digits of Pi, the order
1440 in which the sorted even and odd digits appear will change.
1441 and, for sufficiently large slices of Pi, the quicksort algorithm
1442 in Perl 5.8 won't return the same results even if reinvoked with the
1443 same input. The justification for this rests with quicksort's
1444 worst case behavior. If you run
1446 sort { $a <=> $b } ( 1 .. $N , 1 .. $N );
1448 (something you might approximate if you wanted to merge two sorted
1449 arrays using sort), doubling $N doesn't just double the quicksort time,
1450 it I<quadruples> it. Quicksort has a worst case run time that can
1451 grow like N**2, so-called I<quadratic> behaviour, and it can happen
1452 on patterns that may well arise in normal use. You won't notice this
1453 for small arrays, but you I<will> notice it with larger arrays,
1454 and you may not live long enough for the sort to complete on arrays
1455 of a million elements. So the 5.8 quicksort scrambles large arrays
1456 before sorting them, as a statistical defence against quadratic behaviour.
1457 But that means if you sort the same large array twice, ties may be
1458 broken in different ways.
1460 Because of the unpredictability of tie-breaking order, and the quadratic
1461 worst-case behaviour, quicksort was I<almost> replaced completely with
1462 a stable mergesort. I<Stable> means that ties are broken to preserve
1463 the original order of appearance in the input array. So
1465 sort { ($a % 2) <=> ($b % 2) } (3,1,4,1,5,9);
1467 will yield (4,3,1,1,5,9), guaranteed. The even and odd numbers
1468 appear in the output in the same order they appeared in the input.
1469 Mergesort has worst case O(NlogN) behaviour, the best value
1470 attainable. And, ironically, this mergesort does particularly
1471 well where quicksort goes quadratic: mergesort sorts (1..$N, 1..$N)
1472 in O(N) time. But quicksort was rescued at the last moment because
1473 it is faster than mergesort on certain inputs and platforms.
1474 For example, if you really I<don't> care about the order of even
1475 and odd digits, quicksort will run in O(N) time; it's very good
1476 at sorting many repetitions of a small number of distinct elements.
1477 The quicksort divide and conquer strategy works well on platforms
1478 with relatively small, very fast, caches. Eventually, the problem gets
1479 whittled down to one that fits in the cache, from which point it
1480 benefits from the increased memory speed.
1482 Quicksort was rescued by implementing a sort pragma to control aspects
1483 of the sort. The B<stable> subpragma forces stable behaviour,
1484 regardless of algorithm. The B<_quicksort> and B<_mergesort>
1485 subpragmas are heavy-handed ways to select the underlying implementation.
1486 The leading C<_> is a reminder that these subpragmas may not survive
1487 beyond 5.8. More appropriate mechanisms for selecting the implementation
1488 exist, but they wouldn't have arrived in time to save quicksort.
1492 Hashes now use Bob Jenkins "One-at-a-Time" hashing key algorithm
1493 ( http://burtleburtle.net/bob/hash/doobs.html ). This algorithm is
1494 reasonably fast while producing a much better spread of values than
1495 the old hashing algorithm (originally by Chris Torek, later tweaked by
1496 Ilya Zakharevich). Hash values output from the algorithm on a hash of
1497 all 3-char printable ASCII keys comes much closer to passing the
1498 DIEHARD random number generation tests. According to perlbench, this
1499 change has not affected the overall speed of Perl.
1503 unshift() should now be noticeably faster.
1507 =head1 Installation and Configuration Improvements
1509 =head2 Generic Improvements
1515 INSTALL now explains how you can configure Perl to use 64-bit
1516 integers even on non-64-bit platforms.
1520 Policy.sh policy change: if you are reusing a Policy.sh file
1521 (see INSTALL) and you use Configure -Dprefix=/foo/bar and in the old
1522 Policy $prefix eq $siteprefix and $prefix eq $vendorprefix, all of
1523 them will now be changed to the new prefix, /foo/bar. (Previously
1524 only $prefix changed.) If you do not like this new behaviour,
1525 specify prefix, siteprefix, and vendorprefix explicitly.
1529 A new optional location for Perl libraries, otherlibdirs, is available.
1530 It can be used for example for vendor add-ons without disturbing Perl's
1531 own library directories.
1535 In many platforms the vendor-supplied 'cc' is too stripped-down to
1536 build Perl (basically, 'cc' doesn't do ANSI C). If this seems
1537 to be the case and 'cc' does not seem to be the GNU C compiler
1538 'gcc', an automatic attempt is made to find and use 'gcc' instead.
1542 gcc needs to closely track the operating system release to avoid
1543 build problems. If Configure finds that gcc was built for a different
1544 operating system release than is running, it now gives a clearly visible
1545 warning that there may be trouble ahead.
1549 If binary compatibility with the 5.005 release is not wanted, Configure
1550 no longer suggests including the 5.005 modules in @INC.
1554 Configure C<-S> can now run non-interactively.
1558 Configure support for pdp11-style memory models has been removed due
1563 configure.gnu now works with options with whitespace in them.
1567 installperl now outputs everything to STDERR.
1571 $Config{byteorder} is now computed dynamically (this is more robust
1572 with "fat binaries" where an executable image contains binaries for
1573 more than one binary platform.)
1577 Because PerlIO is now the default on most platforms, "-perlio" doesn't
1578 get appended to the $Config{archname} (also known as $^O) anymore.
1579 Instead, if you explicitly choose not to use perlio (Configure command
1580 line option -Uuseperlio), you will get "-stdio" appended.
1584 Another change related to the architecture name is that "-64all"
1585 (-Duse64bitall, or "maximally 64-bit") is appended only if your
1586 pointers are 64 bits wide. (To be exact, the use64bitall is ignored.)
1590 In AFS installations one can configure the root of the AFS to be
1591 somewhere else than the default F</afs> by using the Configure
1592 parameter C<-Dafsroot=/some/where/else>.
1596 APPLLIB_EXP, a less-know configuration-time definition, has been
1597 documented. It can be used to prepend site-specific directories
1598 to Perl's default search path (@INC), see INSTALL for information.
1602 The version of Berkeley DB used when the Perl (and, presumably, the
1603 DB_File extension) was built is now available as
1604 C<@Config{qw(db_version_major db_version_minor db_version_patch)}>
1605 from Perl and as C<DB_VERSION_MAJOR_CFG DB_VERSION_MINOR_CFG
1606 DB_VERSION_PATCH_CFG> from C.
1610 Building Berkeley DB3 for compatibility modes for DB, NDBM, and ODBM
1611 has been documented in INSTALL.
1615 If you have CPAN access (either network or a local copy such as a
1616 CD-ROM) you can during specify extra modules to Configure to build and
1617 install with Perl using the -Dextras=... option. See INSTALL for
1622 In addition to config.over a new override file, config.arch, is
1623 available. That is supposed to be used by hints file writers for
1624 architecture-wide changes (as opposed to config.over which is for
1629 If your file system supports symbolic links you can build Perl outside
1630 of the source directory by
1632 mkdir /tmp/perl/build/directory
1633 cd /tmp/perl/build/directory
1634 sh /path/to/perl/source/Configure -Dmksymlinks ...
1636 This will create in /tmp/perl/build/directory a tree of symbolic links
1637 pointing to files in /path/to/perl/source. The original files are left
1638 unaffected. After Configure has finished you can just say
1642 and Perl will be built and tested, all in /tmp/perl/build/directory.
1646 For Perl developers several new make targets for profiling
1647 and debugging have been added, see L<perlhack>.
1653 Use of the F<gprof> tool to profile Perl has been documented in
1654 L<perlhack>. There is a make target called "perl.gprof" for
1655 generating a gprofiled Perl executable.
1659 If you have GCC 3, there is a make target called "perl.gcov" for
1660 creating a gcoved Perl executable for coverage analysis. See
1665 If you are on IRIX or Tru64 platforms, new profiling/debugging options
1666 have been added, see L<perlhack> for more information about pixie and
1673 Guidelines of how to construct minimal Perl installations have
1674 been added to INSTALL.
1678 The Thread extension is now not built at all under ithreads
1679 (C<Configure -Duseithreads>) because it wouldn't work anyway (the
1680 Thread extension requires being Configured with C<-Duse5005threads>).
1682 But note that the Thread.pm interface is now shared by both
1687 The Gconvert macro ($Config{d_Gconvert}) used by perl for stringifying
1688 floating-point numbers is now more picky about using sprintf %.*g
1689 rules for the conversion. Some platforms that used to use gcvt may
1690 now resort to the slower sprintf.
1694 =head2 New Or Improved Platforms
1696 For the list of platforms known to support Perl,
1697 see L<perlport/"Supported Platforms">.
1703 AIX dynamic loading should be now better supported.
1707 AIX should now work better with gcc, threads, and 64-bitness. Also the
1708 long doubles support in AIX should be better now. See L<perlaix>.
1712 After a long pause, AmigaOS has been verified to be happy with Perl.
1716 AtheOS ( http://www.atheos.cx/ ) is a new platform.
1720 BeOS has been reclaimed.
1724 DG/UX platform now supports the 5.005-style threads. See L<perldgux>.
1728 DYNIX/ptx platform (a.k.a. dynixptx) is supported at or near osvers 4.5.2.
1732 EBCDIC platforms (z/OS, also known as OS/390, POSIX-BC, and VM/ESA)
1733 have been regained. Many test suite tests still fail and the
1734 co-existence of Unicode and EBCDIC isn't quite settled, but the
1735 situation is much better than with Perl 5.6. See L<perlos390>,
1736 L<perlbs2000> (for POSIX-BC), and L<perlvmesa> for more information.
1740 Building perl with -Duseithreads or -Duse5005threads now works under
1741 HP-UX 10.20 (previously it only worked under 10.30 or later). You will
1742 need a thread library package installed. See README.hpux.
1746 MacOS Classic (MacPerl has of course been available since
1747 perl 5.004 but now the source code bases of standard Perl
1748 and MacPerl have been synchronised)
1752 MacOS X (or Darwin) should now be able to build Perl even on HFS+
1753 filesystems. (The case-insensitivity confused the Perl build process.)
1757 NCR MP-RAS is now supported.
1761 All the NetBSD specific patches (except for the installation
1762 specific ones) have been merged back to the main distribution.
1766 NetWare from Novell is now supported. See L<perlnetware>.
1770 NonStop-UX is now supported.
1774 NEC SUPER-UX is now supported.
1778 All the OpenBSD specific patches (except for the installation
1779 specific ones) have been merged back to the main distribution.
1783 Perl has been tested with the GNU pth userlevel thread package
1784 ( http://www.gnu.org/software/pth/pth.html ) . All but one thread
1785 test worked, and that one failure was because of test results arriving
1786 in unexpected order.
1790 Amdahl UTS UNIX mainframe platform is now supported.
1794 WinCE is now supported. See L<perlce>.
1798 z/OS (formerly known as OS/390, formerly known as MVS OE) has now
1799 support for dynamic loading. This is not selected by default,
1800 however, you must specify -Dusedl in the arguments of Configure.
1804 =head1 Selected Bug Fixes
1806 Numerous memory leaks and uninitialized memory accesses have been
1807 hunted down. Most importantly anonymous subs used to leak quite
1814 The autouse pragma didn't work for Multi::Part::Function::Names.
1818 caller() could cause core dumps in certain situations. Carp was sometimes
1819 affected by this problem.
1823 chop(@list) in list context returned the characters chopped in
1824 reverse order. This has been reversed to be in the right order.
1828 Configure no longer includes the DBM libraries (dbm, gdbm, db, ndbm)
1829 when building the Perl binary. The only exception to this is SunOS 4.x,
1834 The behaviour of non-decimal but numeric string constants such as
1835 "0x23" was platform-dependent: in some platforms that was seen as 35,
1836 in some as 0, in some as a floating point number (don't ask). This
1837 was caused by Perl using the operating system libraries in a situation
1838 where the result of the string to number conversion is undefined: now
1839 Perl consistently handles such strings as zero in numeric contexts.
1843 The order of DESTROYs has been made more predictable.
1847 Several debugger fixes: exit code now reflects the script exit code,
1848 condition C<"0"> now treated correctly, the C<d> command now checks
1849 line number, the C<$.> no longer gets corrupted, all debugger output
1850 now goes correctly to the socket if RemotePort is set.
1854 Perl 5.6.0 could emit spurious warnings about redefinition of dl_error()
1855 when statically building extensions into perl. This has been corrected.
1859 L<dprofpp> -R didn't work.
1863 C<*foo{FORMAT}> now works.
1866 Infinity is now recognized as a number.
1870 UNIVERSAL::isa no longer caches methods incorrectly. (This broke
1871 the Tk extension with 5.6.0.)
1875 Lexicals I: lexicals outside an eval "" weren't resolved
1876 correctly inside a subroutine definition inside the eval "" if they
1877 were not already referenced in the top level of the eval""ed code.
1881 Lexicals II: lexicals leaked at file scope into subroutines that
1882 were declared before the lexicals.
1886 Lexical warnings now propagating correctly between scopes
1887 and into C<eval "...">.
1891 C<use warnings qw(FATAL all)> did not work as intended. This has been
1896 warnings::enabled() now reports the state of $^W correctly if the caller
1897 isn't using lexical warnings.
1901 Line renumbering with eval and C<#line> now works.
1905 Fixed numerous memory leaks, especially in eval "".
1909 mkdir() now ignores trailing slashes in the directory name,
1910 as mandated by POSIX.
1914 Some versions of glibc have a broken modfl(). This affects builds
1915 with C<-Duselongdouble>. This version of Perl detects this brokenness
1916 and has a workaround for it. The glibc release 2.2.2 is known to have
1917 fixed the modfl() bug.
1921 Modulus of unsigned numbers now works (4063328477 % 65535 used to
1922 return 27406, instead of 27047).
1926 Some "not a number" warnings introduced in 5.6.0 eliminated to be
1927 more compatible with 5.005. Infinity is now recognised as a number.
1931 Numeric conversions did not recognize changes in the string value
1932 properly in certain circumstances.
1936 Attributes (like :shared) didn't work with our().
1940 our() variables will not cause "will not stay shared" warnings.
1944 "our" variables of the same name declared in two sibling blocks
1945 resulted in bogus warnings about "redeclaration" of the variables.
1946 The problem has been corrected.
1950 pack "Z" now correctly terminates the string with "\0".
1954 Fix password routines which in some shadow password platforms
1955 (e.g. HP-UX) caused getpwent() to return every other entry.
1959 The PERL5OPT environment variable (for passing command line arguments
1960 to Perl) didn't work for more than a single group of options.
1964 PERL5OPT with embedded spaces didn't work.
1968 printf() no longer resets the numeric locale to "C".
1972 C<qw(a\\b)> now parses correctly as C<'a\\b'>.
1976 pos() did not return the correct value within s///ge in earlier
1977 versions. This is now handled correctly.
1981 Printing quads (64-bit integers) with printf/sprintf now works
1982 without the q L ll prefixes (assuming you are on a quad-capable platform).
1986 Regular expressions on references and overloaded scalars now work.
1990 Right-hand side magic (GMAGIC) could in many cases such as string
1991 concatenation be invoked too many times.
1995 scalar() now forces scalar context even when used in void context.
1999 SOCKS support is now much more robust.
2003 sort() arguments are now compiled in the right wantarray context
2004 (they were accidentally using the context of the sort() itself).
2005 The comparison block is now run in scalar context, and the arguments
2006 to be sorted are always provided list context.
2010 Changed the POSIX character class C<[[:space:]]> to include the (very
2011 rarely used) vertical tab character. Added a new POSIX-ish character
2012 class C<[[:blank:]]> which stands for horizontal whitespace
2013 (currently, the space and the tab).
2017 The tainting behaviour of sprintf() has been rationalized. It does
2018 not taint the result of floating point formats anymore, making the
2019 behaviour consistent with that of string interpolation.
2023 Some cases of inconsistent taint propagation (such as within hash
2024 values) have been fixed.
2028 The RE engine found in Perl 5.6.0 accidentally pessimised certain kinds
2029 of simple pattern matches. These are now handled better.
2033 Regular expression debug output (whether through C<use re 'debug'>
2034 or via C<-Dr>) now looks better.
2038 Multi-line matches like C<"a\nxb\n" =~ /(?!\A)x/m> were flawed. The
2043 Use of $& could trigger a core dump under some situations. This
2048 The regular expression captured submatches ($1, $2, ...) are now
2049 more consistently unset if the match fails, instead of leaving false
2050 data lying around in them.
2054 readline() on files opened in "slurp" mode could return an extra "" at
2055 the end in certain situations. This has been corrected.
2059 Autovivification of symbolic references of special variables described
2060 in L<perlvar> (as in C<${$num}>) was accidentally disabled. This works
2065 Sys::Syslog ignored the C<LOG_AUTH> constant.
2069 All but the first argument of the IO syswrite() method are now optional.
2073 $AUTOLOAD, sort(), lock(), and spawning subprocesses
2074 in multiple threads simultaneously are now thread-safe.
2078 Tie::ARRAY SPLICE method was broken.
2082 Allow read-only string on left hand side of non-modifying tr///.
2086 If C<STDERR> is tied, warnings caused by C<warn> and C<die> now
2087 correctly pass to it.
2091 Several Unicode fixes.
2097 BOMs (byte order marks) in the beginning of Perl files
2098 (scripts, modules) should now be transparently skipped.
2099 UTF-16 (UCS-2) encoded Perl files should now be read correctly.
2103 The character tables have been updated to Unicode 3.2.0.
2107 Comparing with utf8 data does not magically upgrade non-utf8 data
2108 into utf8. (This was a problem for example if you were mixing data
2109 from I/O and Unicode data: your output might have got magically encoded
2114 Generating illegal Unicode code points like U+FFFE, or the UTF-16
2115 surrogates, now also generates an optional warning.
2119 C<IsAlnum>, C<IsAlpha>, and C<IsWord> now match titlecase.
2123 Concatenation with the C<.> operator or via variable interpolation,
2124 C<eq>, C<substr>, C<reverse>, C<quotemeta>, the C<x> operator,
2125 substitution with C<s///>, single-quoted UTF8, should now work.
2129 The C<tr///> operator now works. Note that the C<tr///CU>
2130 functionality has been removed (but see pack('U0', ...)).
2134 C<eval "v200"> now works.
2138 Perl 5.6.0 parsed m/\x{ab}/ incorrectly, leading to spurious warnings.
2139 This has been corrected.
2143 Zero entries were missing from the Unicode classes like C<IsDigit>.
2149 Large unsigned numbers (those above 2**31) could sometimes lose their
2150 unsignedness, causing bogus results in arithmetic operations.
2154 =head2 Platform Specific Changes and Fixes
2162 Perl now works on post-4.0 BSD/OSes.
2168 Setting C<$0> now works (as much as possible; see L<perlvar> for details).
2174 Numerous updates; currently synchronised with Cygwin 1.3.10.
2178 Previously DYNIX/ptx had problems in its Configure probe for non-blocking I/O.
2184 EPOC update after Perl 5.6.0. See README.epoc.
2190 Perl now works on post-3.0 FreeBSDs.
2196 README.hpux updated; C<Configure -Duse64bitall> now works.
2202 Numerous compilation flag and hint enhancements; accidental mixing
2203 of 32-bit and 64-bit libraries (a doomed attempt) made much harder.
2213 Long doubles should now work (see INSTALL).
2217 Linux previously had problems related to sockaddrlen when using
2218 accept(), revcfrom() (in Perl: recv()), getpeername(), and getsockname().
2226 Compilation of the standard Perl distribution in MacOS Classic should
2227 now work if you have the Metrowerks development environment and
2228 the missing Mac-specific toolkit bits. Contact the macperl mailing
2235 MPE/iX update after Perl 5.6.0. See README.mpeix.
2241 Perl now works on NetBSD/sparc.
2247 Now works with usethreads (see INSTALL).
2253 64-bitness using the Sun Workshop compiler now works.
2257 Tru64 (aka Digital UNIX, aka DEC OSF/1)
2259 The operating system version letter now recorded in $Config{osvers}.
2260 Allow compiling with gcc (previously explicitly forbidden). Compiling
2261 with gcc still not recommended because buggy code results, even with
2268 Fixed various alignment problems that lead into core dumps either
2269 during build or later; no longer dies on math errors at runtime;
2270 now using full quad integers (64 bits), previously was using
2271 only 46 bit integers for speed.
2277 chdir() now works better despite a CRT bug; now works with MULTIPLICITY
2278 (see INSTALL); now works with Perl's malloc.
2280 The tainting of C<%ENV> elements via C<keys> or C<values> was previously
2281 unimplemented. It now works as documented.
2283 The C<waitpid> emulation has been improved. The worst bug (now fixed)
2284 was that a pid of -1 would cause a wildcard search of all processes on
2285 the system. The most significant enhancement is that we can now
2286 usually get the completion status of a terminated process.
2288 POSIX-style signals are now emulated much better on VMS versions prior
2291 The C<system> function and backticks operator have improved
2292 functionality and better error handling.
2294 File access tests now use current process privileges rather than the
2295 user's default privileges, which could sometimes result in a mismatch
2296 between reported access and actual access.
2306 accept() no longer leaks memory.
2310 Borland C++ v5.5 is now a supported compiler that can build Perl.
2311 However, the generated binaries continue to be incompatible with those
2312 generated by the other supported compilers (GCC and Visual C++).
2316 Better chdir() return value for a non-existent directory.
2320 Duping socket handles with open(F, ">&MYSOCK") now works under Windows 9x.
2324 New %ENV entries now propagate to subprocesses.
2328 Current directory entries in %ENV are now correctly propagated to child
2333 $ENV{LIB} now used to search for libs under Visual C.
2337 fork() emulation has been improved in various ways, but still continues
2338 to be experimental. See L<perlfork> for known bugs and caveats.
2342 A failed (pseudo)fork now returns undef and sets errno to EAGAIN.
2346 Win32::GetCwd() correctly returns C:\ instead of C: when at the drive root.
2347 Other bugs in chdir() and Cwd::cwd() have also been fixed.
2351 HTML files will be installed in c:\perl\html instead of c:\perl\lib\pod\html
2355 The makefiles now provide a single switch to bulk-enable all the features
2356 enabled in ActiveState ActivePerl (a popular Win32 binary distribution).
2360 Allow REG_EXPAND_SZ keys in the registry.
2364 Can now send() from all threads, not just the first one.
2368 Fake signal handling reenabled, bugs and all.
2372 %SIG has been enabled under USE_ITHREADS, but its use is completely
2373 unsupported under all configurations.
2377 Less stack reserved per thread so that more threads can run
2378 concurrently. (Still 16M per thread.)
2382 C<File::Spec->tmpdir()> now prefers C:/temp over /tmp
2383 (works better when perl is running as service).
2387 Better UNC path handling under ithreads.
2391 wait(), waitpid() and backticks now return the correct exit status under
2396 winsock handle leak fixed.
2400 The Perl parser has been stress tested using both random input and
2401 Markov chain input and the few found crashes and lockups have been
2408 =head1 New or Changed Diagnostics
2414 The lexical warnings category "deprecated" is no longer a sub-category
2415 of the "syntax" category. It is now a top-level category in its own
2420 All regular expression compilation error messages are now hopefully
2421 easier to understand both because the error message now comes before
2422 the failed regex and because the point of failure is now clearly
2423 marked by a C<E<lt>-- HERE> marker.
2427 The various "opened only for", "on closed", "never opened" warnings
2428 drop the C<main::> prefix for filehandles in the C<main> package,
2429 for example C<STDIN> instead of C<main::STDIN>.
2433 The "Unrecognized escape" warning has been extended to include C<\8>,
2434 C<\9>, and C<\_>. There is no need to escape any of the C<\w> characters.
2438 Two new debugging options have been added: if you have compiled your
2439 Perl with debugging, you can use the -DT and -DR options to trace
2440 tokenising and to add reference counts to displaying variables,
2445 The debugger (perl5db.pl) has been modified to present a more
2446 consistent commands interface, via (CommandSet=580). perl5db.t was
2447 also added to test the changes, and as a placeholder for further tests.
2453 The debugger has a new C<dumpDepth> option to control the maximum
2454 depth to which nested structures are dumped. The C<x> command has
2455 been extended so that C<x N EXPR> dumps out the value of I<EXPR> to a
2456 depth of at most I<N> levels.
2460 The debugger can now show lexical variables if you have the CPAN
2461 module PadWalker installed.
2465 If an attempt to use a (non-blessed) reference as an array index
2466 is made, a warning is given.
2470 C<push @a;> and C<unshift @a;> (with no values to push or unshift)
2471 now give a warning. This may be a problem for generated and evaled
2476 If you try to L<perlfunc/pack> a number less than 0 or larger than 255
2477 using the C<"C"> format you will get an optional warning. Similarly
2478 for the C<"c"> format and a number less than -128 or more than 127.
2482 Certain regex modifiers such as C<(?o)> make sense only if applied to
2483 the entire regex. You will get an optional warning if you try to do
2488 Using arrays or hashes as references (e.g. C<< %foo->{bar} >>
2489 has been deprecated for a while. Now you will get an optional warning.
2493 Using C<sort> in scalar context now issues an optional warning.
2494 This didn't do anything useful, as the sort was not performed.
2498 =head1 Changed Internals
2504 perlapi.pod (a companion to perlguts) now attempts to document the
2509 You can now build a really minimal perl called microperl.
2510 Building microperl does not require even running Configure;
2511 C<make -f Makefile.micro> should be enough. Beware: microperl makes
2512 many assumptions, some of which may be too bold; the resulting
2513 executable may crash or otherwise misbehave in wondrous ways.
2514 For careful hackers only.
2518 Added rsignal(), whichsig(), do_join(), op_clear, op_null,
2519 ptr_table_clear(), ptr_table_free(), sv_setref_uv(), and several UTF-8
2520 interfaces to the publicised API. For the full list of the available
2521 APIs see L<perlapi>.
2525 Made possible to propagate customised exceptions via croak()ing.
2529 Now xsubs can have attributes just like subs. (Well, at least the
2530 built-in attributes.)
2534 dTHR and djSP have been obsoleted; the former removed (because it's
2535 a no-op) and the latter replaced with dSP.
2539 PERL_OBJECT has been completely removed.
2543 The MAGIC constants (e.g. C<'P'>) have been macrofied
2544 (e.g. C<PERL_MAGIC_TIED>) for better source code readability
2545 and maintainability.
2549 The regex compiler now maintains a structure that identifies nodes in
2550 the compiled bytecode with the corresponding syntactic features of the
2551 original regex expression. The information is attached to the new
2552 C<offsets> member of the C<struct regexp>. See L<perldebguts> for more
2553 complete information.
2557 The C code has been made much more C<gcc -Wall> clean. Some warning
2558 messages still remain in some platforms, so if you are compiling with
2559 gcc you may see some warnings about dubious practices. The warnings
2560 are being worked on.
2564 F<perly.c>, F<sv.c>, and F<sv.h> have now been extensively commented.
2568 Documentation on how to use the Perl source repository has been added
2569 to F<Porting/repository.pod>.
2573 There are now several profiling make targets.
2577 =head1 Security Vulnerability Closed
2579 (This change was already made in 5.7.0 but bears repeating here.)
2581 A potential security vulnerability in the optional suidperl component
2582 of Perl was identified in August 2000. suidperl is neither built nor
2583 installed by default. As of November 2001 the only known vulnerable
2584 platform is Linux, most likely all Linux distributions. CERT and
2585 various vendors and distributors have been alerted about the vulnerability.
2586 See http://www.cpan.org/src/5.0/sperl-2000-08-05/sperl-2000-08-05.txt
2587 for more information.
2589 The problem was caused by Perl trying to report a suspected security
2590 exploit attempt using an external program, /bin/mail. On Linux
2591 platforms the /bin/mail program had an undocumented feature which
2592 when combined with suidperl gave access to a root shell, resulting in
2593 a serious compromise instead of reporting the exploit attempt. If you
2594 don't have /bin/mail, or if you have 'safe setuid scripts', or if
2595 suidperl is not installed, you are safe.
2597 The exploit attempt reporting feature has been completely removed from
2598 Perl 5.8.0 (and the maintenance release 5.6.1, and it was removed also
2599 from all the Perl 5.7 releases), so that particular vulnerability
2600 isn't there anymore. However, further security vulnerabilities are,
2601 unfortunately, always possible. The suidperl functionality is most
2602 probably going to be removed in Perl 5.10. In any case, suidperl
2603 should only be used by security experts who know exactly what they are
2604 doing and why they are using suidperl instead of some other solution
2605 such as sudo ( see http://www.courtesan.com/sudo/ ).
2609 Several new tests have been added, especially for the F<lib>
2610 subsection. There are now about 56 000 individual tests (spread over
2611 about 620 test scripts), in the regression suite (5.6.1 has about
2612 11700 tests, in 258 test scripts) Many of the new tests are introduced
2613 by the new modules, but still in general Perl is now more thoroughly
2616 Because of the large number of tests, running the regression suite
2617 will take considerably longer time than it used to: expect the suite
2618 to take up to 4-5 times longer to run than in perl 5.6. In a really
2619 fast machine you can hope to finish the suite in about 6-8 minutes
2622 The tests are now reported in a different order than in earlier Perls.
2623 (This happens because the test scripts from under t/lib have been moved
2624 to be closer to the library/extension they are testing.)
2626 =head1 Known Problems
2634 In AIX 4.2 Perl extensions that use C++ functions that use statics
2635 may have problems in that the statics are not getting initialized.
2636 In newer AIX releases this has been solved by linking Perl with
2637 the libC_r library, but unfortunately in AIX 4.2 the said library
2638 has an obscure bug where the various functions related to time
2639 (such as time() and gettimeofday()) return broken values, and
2640 therefore in AIX 4.2 Perl is not linked against the libC_r.
2644 vac 5.0.0.0 May Produce Buggy Code For Perl
2646 The AIX C compiler vac version 5.0.0.0 may produce buggy code,
2647 resulting in few random tests failing, but when the failing tests
2648 are run by hand, they succeed. We suggest upgrading to at least
2649 vac version 5.0.1.0, that has been known to compile Perl correctly.
2650 "lslpp -L|grep vac.C" will tell you the vac version. See README.aix.
2654 If building threaded Perl, you may get compilation warning from pp_sys.c:
2656 "pp_sys.c", line 4651.39: 1506-280 (W) Function argument assignment between types "unsigned char*" and "const void*" is not allowed.
2658 This is harmless; it is caused by the getnetbyaddr() and getnetbyaddr_r()
2659 having slightly different types for their first argument.
2663 =head2 Amiga Perl Invoking Mystery
2665 One cannot call Perl using the C<volume:> syntax, that is, C<perl -v>
2666 works, but for example C<bin:perl -v> doesn't. The exact reason isn't
2667 known but the current suspect is the F<ixemul> library.
2669 =head2 FreeBSD Failing locale Test 117 For ISO8859-15 Locales
2671 The ISO8859-15 locales may fail the locale test 117 in FreeBSD.
2672 This is caused by the characters \xFF (y with diaeresis) and \xBE
2673 (Y with diaeresis) not behaving correctly when being matched
2676 =head2 mod_perl 1.26 Doesn't Build With Threaded Perl
2678 Use mod_perl 1.27 or higher.
2680 =head2 lib/ftmp-security tests warn 'system possibly insecure'
2682 Don't panic. Read INSTALL 'make test' section instead.
2684 =head2 HP-UX lib/posix Subtest 9 Fails When LP64-Configured
2686 If perl is configured with -Duse64bitall, the successful result of the
2687 subtest 10 of lib/posix may arrive before the successful result of the
2688 subtest 9, which confuses the test harness so much that it thinks the
2691 =head2 Linux With Sfio Fails op/misc Test 48
2697 Please remember to set your environment variable LC_ALL to "C"
2698 (setenv LC_ALL C) before running "make test" to avoid a lot of
2699 warnings about the broken locales of Mac OS X.
2701 The following tests are known to fail:
2703 Failed Test Stat Wstat Total Fail Failed List of Failed
2704 -------------------------------------------------------------------------
2705 ../ext/DB_File/t/db-btree.t 0 11 ?? ?? % ??
2706 ../ext/DB_File/t/db-recno.t 149 3 2.01% 61 63 65
2707 ../ext/POSIX/t/posix.t 31 1 3.23% 10
2709 If you are building on a UFS partition, you will also probably see
2710 t/op/stat.t subtest #9 fail. This is caused by Darwin's UFS not
2711 supporting inode change time.
2713 =head2 op/sprintf tests 91, 129, and 130
2715 The op/sprintf tests 91, 129, and 130 are known to fail on some platforms.
2716 Examples include any platform using sfio, and Compaq/Tandem's NonStop-UX.
2718 The test 91 is known to fail at QNX6 (nto), because C<sprintf '%e',0>
2719 incorrectly produces C<0.000000e+0> instead of C<0.000000e+00>.
2721 For the tests 129 and 130 the failing platforms do not comply with
2722 the ANSI C Standard, line 19ff on page 134 of ANSI X3.159 1989 to
2723 be exact. (They produce something other than "1" and "-1" when
2724 formatting 0.6 and -0.6 using the printf format "%.0f", most often
2725 they produce "0" and "-0".)
2727 =head2 Failure of Thread (5.005-style) tests
2729 B<Note that support for 5.005-style threading remains experimental
2730 and practically unsupported.>
2732 The following tests are known to fail due to fundamental problems in
2733 the 5.005 threading implementation. These are not new failures--Perl
2734 5.005_0x has the same bugs, but didn't have these tests.
2736 ../ext/List/Util/t/first.t 255 65280 7 4 57.14% 2 5-7
2737 ../lib/English.t 2 512 54 2 3.70% 2-3
2738 ../lib/Filter/Simple/t/data.t 6 3 50.00% 1-3
2739 ../lib/Filter/Simple/t/filter_onl 9 3 33.33% 1-2 5
2740 ../lib/autouse.t 10 1 10.00% 4
2741 op/flip.t 15 1 6.67% 15
2743 These failures are unlikely to get fixed as the 5.005-style
2744 threads are considered fundamentally broken.
2748 Failed Test Stat Wstat Total Fail Failed List of Failed
2749 -------------------------------------------------------------------------
2750 ../ext/Socket/socketpair.t 1 256 45 1 2.22% 12
2751 ../lib/Math/Trig.t 26 1 3.85% 25
2752 ../lib/warnings.t 460 1 0.22% 425
2753 io/fs.t 36 1 2.78% 31
2754 op/numconvert.t 1440 13 0.90% 208 509-510
2755 657-658 665-666 829-830 989-990 1149-1150
2757 =head2 UNICOS and UNICOS/mk
2759 The io/fs test #31 is failing because in UNICOS and UNICOS/mk the Perl
2760 truncate() cannot be used to grow the size of filehandles, only to
2761 reduce the size. The workaround is to truncate files instead of
2770 During Configure the test
2772 Guessing which symbols your C compiler and preprocessor define...
2774 will probably fail with error messages like
2776 CC-20 cc: ERROR File = try.c, Line = 3
2777 The identifier "bad" is undefined.
2779 bad switch yylook 79bad switch yylook 79bad switch yylook 79bad switch yylook 79#ifdef A29K
2782 CC-65 cc: ERROR File = try.c, Line = 3
2783 A semicolon is expected at this point.
2785 This is caused by a bug in awk utility of UNICOS/mk. You can ignore
2786 the error, but it does cause a slight problem: you cannot fully
2787 benefit from the h2ph utility (see L<h2ph>) that can be used to
2788 convert C headers to Perl libraries, mainly used to be able to access
2789 from Perl the constants defined using C preprocessor, cpp. Because of
2790 the above error parts of the converted headers will be invisible.
2791 Luckily, these days the need for h2ph is rare.
2795 If building Perl with the interpreter threads (ithreads), the
2796 getgrent(), getgrnam(), and getgrgid() functions cannot return the
2797 list of the group members due to a bug in the multithreaded support of
2798 UNICOS/mk. What this means that in list context the functions will
2799 return only three values, not four.
2805 There are a few known test failures, see L<perluts>.
2809 There should be no reported test failures with a default configuration,
2810 though there are a number of tests marked TODO that point to areas
2811 needing further debugging and/or porting work.
2815 In multi-CPU boxes there are some problems with the I/O buffering:
2816 some output may appear twice.
2818 =head2 XML::Parser not working
2820 Use XML::Parser 2.31 or later.
2822 =head2 Localising a Tied Variable Leaks Memory
2825 tie my %tie_hash => 'Tie::StdHash';
2829 local($tie_hash{Foo}) = 1; # leaks
2831 Code like the above is known to leak memory every time the local()
2834 =head2 z/OS (OS/390)
2836 z/OS has rather many test failures but the situation is actually
2837 better than it was in 5.6.0, it's just that so many new modules and
2838 tests have been added.
2840 Failed Test Stat Wstat Total Fail Failed List of Failed
2841 -------------------------------------------------------------------------------
2842 ../ext/Data/Dumper/t/dumper.t 339 8 2.36% 311 314 325 327
2844 ../ext/IO/lib/IO/t/io_unix.t 5 4 80.00% 2-5
2845 ../ext/Storable/t/utf8hash.t 10 2560 148 10 6.76% 1 5 72 76 143-148
2846 ../lib/utf8.t 94 13 13.83% 27 30-31 43 46 73
2849 ../lib/ExtUtils/t/Constant.t 121 30976 48 48 100.00% 1-48
2850 ../lib/ExtUtils/t/Embed.t 9 9 100.00% 1-9
2851 op/pat.t 900 9 1.00% 242-243 665 776
2853 op/sprintf.t 224 3 1.34% 98 100 136
2854 op/tr.t 97 5 5.15% 63 71-74
2855 run/fresh_perl.t 94 3 3.19% 92-94
2856 uni/fold.t 780 6 0.77% 61 169 196 661
2859 =head2 Localising Tied Arrays and Hashes Is Broken
2863 doesn't work as one would expect: the old value is restored
2866 =head2 Self-tying of Arrays and Hashes Is Forbidden
2868 Self-tying of arrays and hashes is broken in rather deep and
2869 hard-to-fix ways. As a stop-gap measure to avoid people from getting
2870 frustrated at the mysterious results (core dumps, most often) it is
2871 for now forbidden (you will get a fatal error even from an attempt).
2873 =head2 Building Extensions Can Fail Because Of Largefiles
2875 Some extensions like mod_perl are known to have issues with
2876 `largefiles', a change brought by Perl 5.6.0 in which file offsets
2877 default to 64 bits wide, where supported. Modules may fail to compile
2878 at all or compile and work incorrectly. Currently there is no good
2879 solution for the problem, but Configure now provides appropriate
2880 non-largefile ccflags, ldflags, libswanted, and libs in the %Config
2881 hash (e.g., $Config{ccflags_nolargefiles}) so the extensions that are
2882 having problems can try configuring themselves without the
2883 largefileness. This is admittedly not a clean solution, and the
2884 solution may not even work at all. One potential failure is whether
2885 one can (or, if one can, whether it's a good idea) link together at
2886 all binaries with different ideas about file offsets, all this is
2889 =head2 Unicode Support on EBCDIC Still Spotty
2891 Though mostly working, Unicode support still has problem spots on
2892 EBCDIC platforms. One such known spot are the C<\p{}> and C<\P{}>
2893 regular expression constructs for code points less than 256: the
2894 pP are testing for Unicode code points, not knowing about EBCDIC.
2896 =head2 The Compiler Suite Is Still Experimental
2898 The compiler suite is slowly getting better but it continues to be
2899 highly experimental. Use in production environments is discouraged.
2901 =head2 The Long Double Support Is Still Experimental
2903 The ability to configure Perl's numbers to use "long doubles",
2904 floating point numbers of hopefully better accuracy, is still
2905 experimental. The implementations of long doubles are not yet
2906 widespread and the existing implementations are not quite mature
2907 or standardised, therefore trying to support them is a rare
2908 and moving target. The gain of more precision may also be offset
2909 by slowdown in computations (more bits to move around, and the
2910 operations are more likely to be executed by less optimised
2913 =head2 Seen In Perl 5.7 But Gone Now
2915 C<Time::Piece> (previously known as C<Time::Object>) was removed
2916 because it was felt that it didn't have enough value in it to be a
2917 core module. It is still a useful module, though, and is available
2920 =head1 Reporting Bugs
2922 If you find what you think is a bug, you might check the articles
2923 recently posted to the comp.lang.perl.misc newsgroup and the perl
2924 bug database at http://bugs.perl.org/ There may also be
2925 information at http://www.perl.com/ , the Perl Home Page.
2927 If you believe you have an unreported bug, please run the B<perlbug>
2928 program included with your release. Be sure to trim your bug down
2929 to a tiny but sufficient test case. Your bug report, along with the
2930 output of C<perl -V>, will be sent off to perlbug@perl.org to be
2931 analysed by the Perl porting team.
2935 The F<Changes> file for exhaustive details on what changed.
2937 The F<INSTALL> file for how to build Perl.
2939 The F<README> file for general stuff.
2941 The F<Artistic> and F<Copying> files for copyright information.
2945 Written by Jarkko Hietaniemi <F<jhi@iki.fi>>.