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 without
59 it many new features of Perl 5.8 cannot be used. In other words:
60 you just have to recompile your modules containing XS code, sorry
63 In future releases of Perl, non-PerlIO aware XS modules may become
64 completely unsupported. This shouldn't be too difficult for module
65 authors, however: PerlIO has been designed as a drop-in replacement
66 (at the source code level) for the stdio interface.
68 Depending on your platform, there are also other reasons why
69 we decided to break binary compatibility, please read on.
71 =head2 64-bit platforms and malloc
73 If your pointers are 64 bits wide, the Perl malloc is no longer being
74 used because it does not work well with 8-byte pointers. Also,
75 usually the system mallocs on such platforms are much better optimized
76 for such large memory models than the Perl malloc. Some memory-hungry
77 Perl applications like the PDL don't work well with Perl's malloc.
78 Finally, other applications than Perl (like modperl) tend to prefer
79 the system malloc. Such platforms include Alpha and 64-bit HPPA,
82 =head2 AIX Dynaloading
84 The AIX dynaloading now uses in AIX releases 4.3 and newer the native
85 dlopen interface of AIX instead of the old emulated interface. This
86 change will probably break backward compatibility with compiled
87 modules. The change was made to make Perl more compliant with other
88 applications like modperl which are using the AIX native interface.
90 =head2 Attributes for C<my> variables now handled at run-time.
92 The C<my EXPR : ATTRS> syntax now applies variable attributes at
93 run-time. (Subroutine and C<our> variables still get attributes applied
94 at compile-time.) See L<attributes> for additional details. In particular,
95 however, this allows variable attributes to be useful for C<tie> interfaces,
96 which was a deficiency of earlier releases. Note that the new semantics
97 doesn't work with the Attribute::Handlers module (as of version 0.76).
99 =head2 Socket Extension Dynamic in VMS
101 The Socket extension is now dynamically loaded instead of being
102 statically built in. This may or may not be a problem with ancient
103 TCP/IP stacks of VMS: we do not know since we weren't able to test
104 Perl in such configurations.
106 =head2 IEEE-format Floating Point Default on OpenVMS Alpha
108 Perl now uses IEEE format (T_FLOAT) as the default internal floating
109 point format on OpenVMS Alpha, potentially breaking binary compatibility
110 with external libraries or existing data. G_FLOAT is still available as
111 a configuration option. The default on VAX (D_FLOAT) has not changed.
113 =head2 New Unicode Properties
115 Unicode I<scripts> are now supported. Scripts are similar to (and superior
116 to) Unicode I<blocks>. The difference between scripts and blocks is that
117 scripts are the glyphs used by a language or a group of languages, while
118 the blocks are more artificial groupings of (mostly) 256 characters based
119 on the Unicode numbering.
121 In general, scripts are more inclusive, but not universally so. For
122 example, while the script C<Latin> includes all the Latin characters and
123 their various diacritic-adorned versions, it does not include the various
124 punctuation or digits (since they are not solely C<Latin>).
126 A number of other properties are now supported, including C<\p{L&}>,
127 C<\p{Any}> C<\p{Assigned}>, C<\p{Unassigned}>, C<\p{Blank}> and
128 C<\p{SpacePerl}> (along with their C<\P{...}> versions, of course).
129 See L<perlunicode> for details, and more additions.
131 The C<In> or C<Is> prefix to names used with the C<\p{...}> and C<\P{...}>
132 are now almost always optional. The only exception is that a C<In> prefix
133 is required to signify a Unicode block when a block name conflicts with a
134 script name. For example, C<\p{Tibetan}> refers to the script, while
135 C<\p{InTibetan}> refers to the block. When there is no name conflict, you
136 can omit the C<In> from the block name (e.g. C<\p{BraillePatterns}>), but
137 to be safe, it's probably best to always use the C<In>).
139 =head2 REF(...) Instead Of SCALAR(...)
141 A reference to a reference now stringifies as "REF(0x81485ec)" instead
142 of "SCALAR(0x81485ec)" in order to be more consistent with the return
145 =head2 pack/unpack D/F recycled
147 The undocumented pack/unpack template letters D/F have been recycled
148 for better use: now they stand for long double (if supported by the
149 platform) and NV (Perl internal floating point type). (They used
150 to be aliases for d/f, but you never knew that.)
158 The semantics of bless(REF, REF) were unclear and until someone proves
159 it to make some sense, it is forbidden.
163 The obsolete chat2 library that should never have been allowed
164 to escape the laboratory has been decommissioned.
168 The builtin dump() function has probably outlived most of its
169 usefulness. The core-dumping functionality will remain in future
170 available as an explicit call to C<CORE::dump()>, but in future
171 releases the behaviour of an unqualified C<dump()> call may change.
175 The very dusty examples in the eg/ directory have been removed.
176 Suggestions for new shiny examples welcome but the main issue is that
177 the examples need to be documented, tested and (most importantly)
182 The (bogus) escape sequences \8 and \9 now give an optional warning
183 ("Unrecognized escape passed through"). There is no need to \-escape
188 The list of filenames from glob() (or <...>) is now by default sorted
189 alphabetically to be csh-compliant (which is what happened before
190 in most UNIX platforms). (bsd_glob() does still sort platform
191 natively, ASCII or EBCDIC, unless GLOB_ALPHASORT is specified.)
195 Spurious syntax errors generated in certain situations, when glob()
196 caused File::Glob to be loaded for the first time, have been fixed.
200 Although "you shouldn't do that", it was possible to write code that
201 depends on Perl's hashed key order (Data::Dumper does this). The new
202 algorithm "One-at-a-Time" produces a different hashed key order.
203 More details are in L</"Performance Enhancements">.
207 lstat(FILEHANDLE) now gives a warning because the operation makes no sense.
208 In future releases this may become a fatal error.
212 The C<package;> syntax (C<package> without an argument) has been
213 deprecated. Its semantics were never that clear and its
214 implementation even less so. If you have used that feature to
215 disallow all but fully qualified variables, C<use strict;> instead.
219 The unimplemented POSIX regex features [[.cc.]] and [[=c=]] are still
220 recognised but now cause fatal errors. The previous behaviour of
221 ignoring them by default and warning if requested was unacceptable
222 since it, in a way, falsely promised that the features could be used.
226 The current user-visible implementation of pseudo-hashes (the weird
227 use of the first array element) is deprecated starting from Perl 5.8.0
228 and will be removed in Perl 5.10.0, and the feature will be
229 implemented differently. Not only is the current interface rather
230 ugly, but the current implementation slows down normal array and hash
231 use quite noticeably. The C<fields> pragma interface will remain
232 available. The I<restricted hashes> interface is expected to
233 be the replacement interface (see L<Hash::Util>).
237 The syntaxes C<< @a->[...] >> and C<< %h->{...} >> have now been deprecated.
241 After years of trying the suidperl is considered to be too complex to
242 ever be considered truly secure. The suidperl functionality is likely
243 to be removed in a future release.
247 The 5.005 threads model (module C<Thread>) is deprecated and expected
248 to be removed in Perl 5.10. Multithreaded code should be migrated to
249 the new ithreads model (see L<threads> and L<threads::shared>).
253 The long deprecated uppercase aliases for the string comparison
254 operators (EQ, NE, LT, LE, GE, GT) have now been removed.
258 The tr///C and tr///U features have been removed and will not return;
259 the interface was a mistake. Sorry about that. For similar
260 functionality, see pack('U0', ...) and pack('C0', ...).
264 Earlier Perls treated "sub foo (@bar)" as equivalent to "sub foo (@)".
265 The prototypes are now checked better at compile-time for invalid
266 syntax. An optional warning is generated ("Illegal character in
267 prototype...") but this may be upgraded to a fatal error in a future
272 =head1 Core Enhancements
274 =head2 PerlIO is Now The Default
280 IO is now by default done via PerlIO rather than system's "stdio".
281 PerlIO allows "layers" to be "pushed" onto a file handle to alter the
282 handle's behaviour. Layers can be specified at open time via 3-arg
285 open($fh,'>:crlf :utf8', $path) || ...
287 or on already opened handles via extended C<binmode>:
289 binmode($fh,':encoding(iso-8859-7)');
291 The built-in layers are: unix (low level read/write), stdio (as in
292 previous Perls), perlio (re-implementation of stdio buffering in a
293 portable manner), crlf (does CRLF <=> "\n" translation as on Win32,
294 but available on any platform). A mmap layer may be available if
295 platform supports it (mostly UNIXes).
297 Layers to be applied by default may be specified via the 'open' pragma.
299 See L</"Installation and Configuration Improvements"> for the effects
300 of PerlIO on your architecture name.
304 File handles can be marked as accepting Perl's internal encoding of Unicode
305 (UTF-8 or UTF-EBCDIC depending on platform) by a pseudo layer ":utf8" :
307 open($fh,">:utf8","Uni.txt");
309 Note for EBCDIC users: the pseudo layer ":utf8" is erroneously named
310 for you since it's not UTF-8 what you will be getting but instead
311 UTF-EBCDIC. See L<perlunicode>, L<utf8>, and
312 http://www.unicode.org/unicode/reports/tr16/ for more information.
313 In future releases this naming may change.
317 File handles can translate character encodings from/to Perl's internal
318 Unicode form on read/write via the ":encoding()" layer.
322 File handles can be opened to "in memory" files held in Perl scalars via:
324 open($fh,'>', \$variable) || ...
328 Anonymous temporary files are available without need to
329 'use FileHandle' or other module via
331 open($fh,"+>", undef) || ...
333 That is a literal undef, not an undefined value.
337 The list form of C<open> is now implemented for pipes (at least on UNIX):
339 open($fh,"-|", 'cat', '/etc/motd')
341 creates a pipe, and runs the equivalent of exec('cat', '/etc/motd') in
346 If your locale environment variables (LANGUAGE, LC_ALL, LC_CTYPE, LANG)
347 contain the strings 'UTF-8' or 'UTF8' (case-insensitive matching),
348 the default encoding of your STDIN, STDOUT, and STDERR, and of
349 B<any subsequent file open>, is UTF-8.
353 =head2 Restricted Hashes
355 A restricted hash is restricted to a certain set of keys, no keys
356 outside the set can be added. Also individual keys can be restricted
357 so that the key cannot be deleted and the value cannot be changed.
358 No new syntax is involved: the Hash::Util module is the interface.
362 Perl used to be fragile in that signals arriving at inopportune moments
363 could corrupt Perl's internal state. Now Perl postpones handling of
364 signals until it's safe (between opcodes).
366 This change may have surprising side effects because signals no longer
367 interrupt Perl instantly. Perl will now first finish whatever it was
368 doing, like finishing an internal operation (like sort()) or an
369 external operation (like an I/O operation), and only then look at any
370 arrived signals (and before starting the next operation). No more corrupt
371 internal state since the current operation is always finished first,
372 but the signal may take more time to get heard. Note that breaking
373 out from potentially blocking operations should still work, though.
375 =head2 Unicode Overhaul
377 Unicode in general should be now much more usable than in Perl 5.6.0
378 (or even in 5.6.1). Unicode can be used in hash keys, Unicode in
379 regular expressions should work now, Unicode in tr/// should work now,
380 Unicode in I/O should work now. See L<perluniintro> for introduction
381 and L<perlunicode> for details.
387 The Unicode Character Database coming with Perl has been upgraded
388 to Unicode 3.2.0. For more information, see http://www.unicode.org/ .
392 For developers interested in enhancing Perl's Unicode capabilities:
393 almost all the UCD files are included with the Perl distribution in
394 the F<lib/unicore> subdirectory. The most notable omission, for space
395 considerations, is the Unihan database.
399 The properties \p{Blank} and \p{SpacePerl} have been added. "Blank" is like
400 C isblank(), that is, it contains only "horizontal whitespace" (the space
401 character is, the newline isn't), and the "SpacePerl" is the Unicode
402 equivalent of C<\s> (\p{Space} isn't, since that includes the vertical
403 tabulator character, whereas C<\s> doesn't.)
405 See "New Unicode Properties" earlier in this document for additional
406 information on changes with Unicode properties.
410 =head2 Understanding of Numbers
412 In general a lot of fixing has happened in the area of Perl's
413 understanding of numbers, both integer and floating point. Since in
414 many systems the standard number parsing functions like C<strtoul()>
415 and C<atof()> seem to have bugs, Perl tries to work around their
416 deficiencies. This results hopefully in more accurate numbers.
418 Perl now tries internally to use integer values in numeric conversions
419 and basic arithmetics (+ - * /) if the arguments are integers, and
420 tries also to keep the results stored internally as integers.
421 This change leads to often slightly faster and always less lossy
422 arithmetics. (Previously Perl always preferred floating point numbers
425 =head2 Miscellaneous Changes
431 AUTOLOAD is now lvaluable, meaning that you can add the :lvalue attribute
432 to AUTOLOAD subroutines and you can assign to the AUTOLOAD return value.
436 The $Config{byteorder} (and corresponding BYTEORDER in config.h) was
437 previously wrong in platforms if sizeof(long) was 4, but sizeof(IV)
438 was 8. The byteorder was only sizeof(long) bytes long (1234 or 4321),
439 but now it is correctly sizeof(IV) bytes long, (12345678 or 87654321).
440 (This problem didn't affect Windows platforms.)
442 Also, $Config{byteorder} is now computed dynamically--this is more
443 robust with "fat binaries" where an executable image contains binaries
444 for more than one binary platform, and when cross-compiling.
448 C<perl -d:Module=arg,arg,arg> now works (previously one couldn't pass
449 in multiple arguments.)
453 The builtin dump() now gives an optional warning
454 C<dump() better written as CORE::dump()>,
455 meaning that by default C<dump(...)> is resolved as the builtin
456 dump() which dumps core and aborts, not as (possibly) user-defined
457 C<sub dump>. To call the latter, qualify the call as C<&dump(...)>.
458 (The whole dump() feature is to considered deprecated, and possibly
459 removed/changed in future releases.)
463 chomp() and chop() are now overridable. Note, however, that their
464 prototype (as given by C<prototype("CORE::chomp")> is undefined,
465 because it cannot be expressed and therefore one cannot really write
466 replacements to override these builtins.
470 END blocks are now run even if you exit/die in a BEGIN block.
471 Internally, the execution of END blocks is now controlled by
472 PL_exit_flags & PERL_EXIT_DESTRUCT_END. This enables the new
473 behaviour for Perl embedders. This will default in 5.10. See
478 Formats now support zero-padded decimal fields.
482 Lvalue subroutines can now return C<undef> in list context.
483 However, the lvalue subroutine feature still remains experimental.
487 A lost warning "Can't declare ... dereference in my" has been
488 restored (Perl had it earlier but it became lost in later releases.)
492 A new special regular expression variable has been introduced:
493 C<$^N>, which contains the most-recently closed group (submatch).
497 C<no Module;> now works even if there is no "sub unimport" in the Module.
501 The numerical comparison operators return C<undef> if either operand
502 is a NaN. Previously the behaviour was unspecified.
506 The following builtin functions are now overridable: each(), keys(),
507 pop(), push(), shift(), splice(), unshift().
511 C<pack() / unpack()> now can group template letters with C<()> and then
512 apply repetition/count modifiers on the groups.
516 C<pack() / unpack()> can now process the Perl internal numeric types:
517 IVs, UVs, NVs-- and also long doubles, if supported by the platform.
518 The template letters are C<j>, C<J>, C<F>, and C<D>.
522 C<pack('U0a*', ...)> can now be used to force a string to UTF8.
526 my __PACKAGE__ $obj now works.
530 POSIX::sleep() now returns the number of I<unslept> seconds
531 (as the POSIX standard says), as opposed to CORE::sleep() which
532 returns the number of slept seconds.
536 The printf() and sprintf() now support parameter reordering using the
537 C<%\d+\$> and C<*\d+\$> syntaxes. For example
539 print "%2\$s %1\$s\n", "foo", "bar";
541 will print "bar foo\n". This feature helps in writing
542 internationalised software, and in general when the order
543 of the parameters can vary.
547 prototype(\&) is now available.
551 prototype(\[$@%&]) is now available to implicitly create references
552 (useful for example if you want to emulate the tie() interface).
556 A new command-line option, C<-t> is available. It is the
557 little brother of C<-T>: instead of dying on taint violations,
558 lexical warnings are given. B<This is only meant as a temporary
559 debugging aid while securing the code of old legacy applications.
560 This is not a substitute for -T.>
564 In other taint news, the C<exec LIST> and C<system LIST> have now been
565 considered too risky (think C<exec @ARGV>: it can start any program
566 with any arguments), and now the said forms cause a warning.
567 You should carefully launder the arguments to guarantee their
568 validity. In future releases of Perl the forms will become fatal
569 errors so consider starting laundering now.
573 Tied hash interfaces are now required to have the EXISTS and DELETE
574 methods (either own or inherited).
578 If tr/// is just counting characters, it doesn't attempt to
583 untie() will now call an UNTIE() hook if it exists. See L<perltie>
588 L<utime> now supports C<utime undef, undef, @files> to change the
589 file timestamps to the current time.
593 The rules for allowing underscores (underbars) in numeric constants
594 have been relaxed and simplified: now you can have an underscore
595 simply B<between digits>.
599 Rather than relying on C's argv[0] (which may not contain a full pathname)
600 where possible $^X is now set by asking the operating system.
601 (eg by reading F</proc/self/exe> on Linux, F</proc/curproc/file> on FreeBSD)
605 A new variable, C<${^TAINT}>, indicates whether taint mode is enabled.
609 You can now override the readline() builtin, and this overrides also
610 the <FILEHANDLE> angle bracket operator.
614 The command-line options -s and -F are now recognized on the shebang
619 Use of the C</c> match modifier without an accompanying C</g> modifier
620 elicits a new warning: C<Use of /c modifier is meaningless without /g>.
622 Use of C</c> in substitutions, even with C</g>, elicits
623 C<Use of /c modifier is meaningless in s///>.
625 Use of C</g> with C<split> elicits C<Use of /g modifier is meaningless
630 =head1 Modules and Pragmata
632 =head2 New Modules and Pragmata
638 C<Attribute::Handlers> allows a class to define attribute handlers.
641 use Attribute::Handlers;
642 sub Wolf :ATTR(SCALAR) { print "howl!\n" }
644 # later, in some package using or inheriting from MyPack...
646 my MyPack $Fluffy : Wolf; # the attribute handler Wolf will be called
648 Both variables and routines can have attribute handlers. Handlers can
649 be specific to type (SCALAR, ARRAY, HASH, or CODE), or specific to the
650 exact compilation phase (BEGIN, CHECK, INIT, or END).
654 B<B::Concise> is a new compiler backend for walking the Perl syntax
655 tree, printing concise info about ops, from Stephen McCamant. The
656 output is highly customisable. See L<B::Concise>.
660 The new bignum, bigint, and bigrat pragmas implement transparent
661 bignum support (using the Math::BigInt, Math::BigFloat, and
662 Math::BigRat backends), by Tels.
666 C<Class::ISA> for reporting the search path for a class's ISA tree,
667 by Sean Burke, has been added. See L<Class::ISA>.
671 C<Cwd> has now a split personality: if possible, an XS extension is
672 used, (this will hopefully be faster, more secure, and more robust)
673 but if not possible, the familiar Perl implementation is used.
677 C<Devel::PPPort>, originally from Kenneth Albanowski and now
678 maintained by Paul Marquess, has been added. It is primarily used
679 by C<h2xs> to enhance portability of XS modules between different
684 C<Digest>, frontend module for calculating digests (checksums), from
685 Gisle Aas, has been added. See L<Digest>.
689 C<Digest::MD5> for calculating MD5 digests (checksums) as defined in
690 RFC 1321, from Gisle Aas, has been added. See L<Digest::MD5>.
692 use Digest::MD5 'md5_hex';
694 $digest = md5_hex("Thirsty Camel");
696 print $digest, "\n"; # 01d19d9d2045e005c3f1b80e8b164de1
698 NOTE: the C<MD5> backward compatibility module is deliberately not
699 included since its further use is discouraged.
703 C<Encode>, orginally by Nick Ing-Simmons and now maintained by Dan
704 Kogai, provides a mechanism to translate between different character
705 encodings. Support for Unicode, ISO-8859-1, and ASCII are compiled in
706 to the module. Several other encodings (like the rest of the
707 ISO-8859, CP*/Win*, Mac, KOI8-R, three variants EBCDIC, Chinese,
708 Japanese, and Korean encodings) are included and can be loaded at
709 runtime. (For space considerations, the largest Chinese encodings
710 have been separated into their own CPAN module, Encode::HanExtra,
711 which Encode will use if available). See L<Encode>.
713 Any encoding supported by Encode module is also available to the
714 ":encoding()" layer if PerlIO is used.
718 C<Hash::Util> is the interface to the new I<restricted hashes>
719 feature. (Implemented by Jeffrey Friedl, Nick Ing-Simmons, and
724 C<I18N::Langinfo> can be use to query locale information.
725 See L<I18N::Langinfo>.
729 C<I18N::LangTags> has functions for dealing with RFC3066-style
730 language tags, by Sean Burke. See L<I18N::LangTags>.
734 C<ExtUtils::Constant> is a new tool for extension writers for
735 generating XS code to import C header constants, by Nicholas Clark.
736 See L<ExtUtils::Constant>.
740 C<Filter::Simple> is an easy-to-use frontend to Filter::Util::Call,
741 from Damian Conway. See L<Filter::Simple>.
747 use Filter::Simple sub {
748 while (my ($from, $to) = splice @_, 0, 2) {
757 use MyFilter qr/red/ => 'green';
759 print "red\n"; # this code is filtered, will print "green\n"
760 print "bored\n"; # this code is filtered, will print "bogreen\n"
764 print "red\n"; # this code is not filtered, will print "red\n"
768 C<File::Temp> allows one to create temporary files and directories in
769 an easy, portable, and secure way, by Tim Jenness. See L<File::Temp>.
773 C<Filter::Util::Call> provides you with the framework to write
774 I<Source Filters> in Perl, from Paul Marquess. For most uses the
775 frontend Filter::Simple is to be preferred. See L<Filter::Util::Call>.
779 C<if> is a new pragma for conditional inclusion of modules, from
784 L<libnet> is a collection of perl5 modules related to network
785 programming, from Graham Barr. See L<Net::FTP>, L<Net::NNTP>,
786 L<Net::Ping> (not part of libnet, but related), L<Net::POP3>,
787 L<Net::SMTP>, and L<Net::Time>.
789 Perl installation leaves libnet unconfigured, use F<libnetcfg> to configure.
793 C<List::Util> is a selection of general-utility list subroutines, like
794 sum(), min(), first(), and shuffle(), by Graham Barr. See L<List::Util>.
798 C<Locale::Constants>, C<Locale::Country>, C<Locale::Currency>
799 C<Locale::Language>, and L<Locale::Script>, from Neil Bowers, have
800 been added. They provide the codes for various locale standards, such
801 as "fr" for France, "usd" for US Dollar, and "ja" for Japanese.
805 $country = code2country('jp'); # $country gets 'Japan'
806 $code = country2code('Norway'); # $code gets 'no'
808 See L<Locale::Constants>, L<Locale::Country>, L<Locale::Currency>,
809 and L<Locale::Language>.
813 C<Locale::Maketext> is localization framework from Sean Burke. See
814 L<Locale::Maketext>, and L<Locale::Maketext::TPJ13>. The latter is an
815 article about software localization, originally published in The Perl
816 Journal #13, republished here with kind permission.
820 C<Math::BigRat> for big rational numbers, to accompany Math::BigInt and
821 Math::BigFloat, from Tels.
825 C<Memoize> can make your functions faster by trading space for time,
826 from Mark-Jason Dominus. See L<Memoize>.
830 C<MIME::Base64> allows you to encode data in base64, from Gisle Aas,
831 as defined in RFC 2045 - I<MIME (Multipurpose Internet Mail
836 $encoded = encode_base64('Aladdin:open sesame');
837 $decoded = decode_base64($encoded);
839 print $encoded, "\n"; # "QWxhZGRpbjpvcGVuIHNlc2FtZQ=="
845 C<MIME::QuotedPrint> allows you to encode data in quoted-printable
846 encoding, as defined in RFC 2045 - I<MIME (Multipurpose Internet Mail
847 Extensions)>, from Gisle Aas.
849 use MIME::QuotedPrint;
851 $encoded = encode_qp("Smiley in Unicode: \x{263a}");
852 $decoded = decode_qp($encoded);
854 print $encoded, "\n"; # "Smiley in Unicode: =263A"
856 MIME::QuotedPrint has been enhanced to provide the basic methods
857 necessary to use it with PerlIO::Via as in :
859 use MIME::QuotedPrint;
860 open($fh,">Via(MIME::QuotedPrint)",$path);
862 See L<MIME::QuotedPrint>.
866 C<NEXT> is pseudo-class for method redispatch, from Damian Conway.
871 C<open> is a new pragma for setting the default I/O disciplines
876 C<PerlIO::Scalar> provides the implementation of IO to "in memory"
877 Perl scalars as discussed above, from Nick Ing-Simmons. It also
878 serves as an example of a loadable PerlIO layer. Other future
879 possibilities include PerlIO::Array and PerlIO::Code.
880 See L<PerlIO::Scalar>.
884 C<PerlIO::Via> acts as a PerlIO layer and wraps PerlIO layer
885 functionality provided by a class (typically implemented in perl
886 code), from Nick Ing-Simmons.
888 use MIME::QuotedPrint;
889 open($fh,">Via(MIME::QuotedPrint)",$path);
891 This will automatically convert everything output to C<$fh>
892 to Quoted-Printable. See L<PerlIO::Via>.
896 C<Pod::ParseLink>, by Russ Allbery, has been added,
897 to parse LZ<><> links in pods as described in the new
902 C<Pod::Text::Overstrike>, by Joe Smith, has been added.
903 It converts POD data to formatted overstrike text.
904 See L<Pod::Text::Overstrike>.
908 C<Scalar::Util> is a selection of general-utility scalar subroutines,
909 like blessed(), reftype(), and tainted(). See L<Scalar::Util>.
913 C<sort> is a new pragma for controlling the behaviour of sort().
917 C<Storable> gives persistence to Perl data structures by allowing the
918 storage and retrieval of Perl data to and from files in a fast and
919 compact binary format. Because in effect Storable does serialisation
920 of Perl data structues, with it you can also clone deep, hierarchical
921 datastructures. Storable was originally created by Raphael Manfredi,
922 but it is now maintained by Abhijit Menon-Sen. Storable has been
923 enhanced to understand the two new hash features, Unicode keys and
924 restricted hashes. See L<Storable>.
928 C<Switch>, from Damian Conway, has been added. Just by saying
932 you have C<switch> and C<case> available in Perl.
938 case 1 { print "number 1" }
939 case "a" { print "string a" }
940 case [1..10,42] { print "number in list" }
941 case (@array) { print "number in list" }
942 case /\w+/ { print "pattern" }
943 case qr/\w+/ { print "pattern" }
944 case (%hash) { print "entry in hash" }
945 case (\%hash) { print "entry in hash" }
946 case (\&sub) { print "arg to subroutine" }
947 else { print "previous case not true" }
954 C<Test::More> is yet another framework for writing test scripts,
955 more extensive than Test::Simple, by Michael Schwern. See L<Test::More>.
959 C<Test::Simple> has basic utilities for writing tests, by Michael
960 Schwern. See L<Test::Simple>.
964 C<Text::Balanced> has been added, for extracting delimited text
965 sequences from strings, from Damian Conway.
967 use Text::Balanced 'extract_delimited';
969 ($a, $b) = extract_delimited("'never say never', he never said", "'", '');
971 $a will be "'never say never'", $b will be ', he never said'.
973 In addition to extract_delimited() there are also extract_bracketed(),
974 extract_quotelike(), extract_codeblock(), extract_variable(),
975 extract_tagged(), extract_multiple(), gen_delimited_pat(), and
976 gen_extract_tagged(). With these you can implement rather advanced
977 parsing algorithms. See L<Text::Balanced>.
981 C<threads> is an interface to interpreter threads, by Arthur Bergman.
982 Interpreter threads (ithreads) is the new thread model introduced in
983 Perl 5.6 but only available as an internal interface for extension
984 writers (and for Win32 Perl for C<fork()> emulation). See L<threads>.
988 C<threads::shared> allows data sharing for interpreter threads, from
989 Arthur Bergman. In the ithreads model any data sharing between
990 threads must be explicit, as opposed to the old 5.005 thread model
991 where data sharing was implicit. See L<threads::shared>.
995 C<Tie::File>, by Mark-Jason Dominus, associates a Perl array with the
1000 C<Tie::Memoize>, by Ilya Zakharevich, provides on-demand loaded hashes.
1004 C<Tie::RefHash::Nestable>, by Edward Avis, allows storing hash
1005 references (unlike the standard Tie::RefHash) The module is contained
1006 within Tie::RefHash, see L<Tie::RefHash>.
1010 C<Time::HiRes> provides high resolution timing (ualarm, usleep,
1011 and gettimeofday), from Douglas E. Wegscheid. See L<Time::HiRes>.
1015 C<Unicode::UCD> offers a querying interface to the Unicode Character
1016 Database. See L<Unicode::UCD>.
1020 C<Unicode::Collate> implements the UCA (Unicode Collation Algorithm)
1021 for sorting Unicode strings, by SADAHIRO Tomoyuki. See L<Unicode::Collate>.
1025 C<Unicode::Normalize> implements the various Unicode normalization
1026 forms, by SADAHIRO Tomoyuki. See L<Unicode::Normalize>.
1030 C<XS::Typemap>, by Tim Jenness, is a test extension that exercises XS
1031 typemaps. Nothing gets installed but for extension writers the code
1036 =head2 Updated And Improved Modules and Pragmata
1042 The following independently supported modules have been updated to the
1043 newest versions from CPAN: CGI, CPAN, DB_File, File::Spec, File::Temp,
1044 Getopt::Long, Math::BigFloat, Math::BigInt, the podlators bundle
1045 (Pod::Man, Pod::Text), Pod::LaTeX, Pod::Parser, Storable,
1046 Term::ANSIColor, Test, Text-Tabs+Wrap.
1050 The attributes::reftype() now works on tied arguments.
1054 AutoLoader can now be disabled with C<no AutoLoader;>.
1058 B::Deparse has been significantly enhanced. It now can deparse almost
1059 all of the standard test suite (so that the tests still succeed).
1060 There is a make target "test.deparse" for trying this out.
1064 Class::Struct can now define the classes in compile time.
1068 Class::Struct now assigns the array/hash element if the accessor
1069 is called with an array/hash element as the B<sole> argument.
1073 The return value of Cwd::fastcwd() is now tainted.
1077 Data::Dumper has now an option to sort hashes.
1081 Data::Dumper has now an option to dump code references
1086 DB_File now supports newer Berkeley DB versions, among
1091 Devel::Peek now has an interface for the Perl memory statistics
1092 (this works only if you are using perl's malloc, and if you have
1093 compiled with debugging).
1097 The English module can now be used without the infamous performance
1100 use English '-no_match_vars';
1102 (Assuming, of course, that one doesn't need the troublesome variables
1103 C<$`>, C<$&>, or C<$'>.) Also, introduced C<@LAST_MATCH_START> and
1104 C<@LAST_MATCH_END> English aliases for C<@-> and C<@+>.
1108 ExtUtils::MakeMaker now uses File::Spec internally, which hopefully
1109 leads into better portability.
1113 Fcntl, Socket, and Sys::Syslog have been rewritten to use the
1114 new-style constant dispatch section (see L<ExtUtils::Constant>).
1115 This means that they will be more robust and hopefully faster.
1119 File::Find now chdir()s correctly when chasing symbolic links.
1123 File::Find now has pre- and post-processing callbacks. It also
1124 correctly changes directories when chasing symbolic links. Callbacks
1125 (naughtily) exiting with "next;" instead of "return;" now work.
1129 File::Find is now (again) reentrant. It also has been made
1134 The warnings issued by File::Find now belong to their own category.
1135 You can enable/disable them with C<use/no warnings 'File::Find';>.
1139 File::Glob::glob() renamed to File::Glob::bsd_glob() to avoid
1140 prototype mismatch with CORE::glob().
1144 File::Glob now supports C<GLOB_LIMIT> constant to limit the size of
1145 the returned list of filenames.
1149 IPC::Open3 now allows the use of numeric file descriptors.
1153 IO::Socket has now atmark() method, which returns true if the socket
1154 is positioned at the out-of-band mark. The method is also exportable
1155 as a sockatmark() function.
1159 IO::Socket::INET has support for ReusePort option (if your platform
1160 supports it). The Reuse option now has an alias, ReuseAddr. For clarity
1161 you may want to prefer ReuseAddr.
1165 IO::Socket::INET now supports C<LocalPort> of zero (usually meaning
1166 that the operating system will make one up.)
1170 use lib now works identically to @INC. Removing directories
1171 with 'no lib' now works.
1175 Math::BigFloat and Math::BigInt have undergone a full rewrite.
1176 They are now magnitudes faster, and they support various
1177 bignum libraries such as GMP and PARI as their backends.
1181 Math::Complex handles inf, NaN etc., better.
1185 Net::Ping has been muchly enhanced: multihoming is now supported,
1186 Win32 functionality is better, there is now time measuring
1187 functionality (optionally high-resolution using Time::HiRes),
1188 and there is now "external" protocol which uses Net::Ping::External
1189 module which runs your external ping utility and parses the output.
1190 A version of Net::Ping::External is available in CPAN.
1192 Note that some of the Net::Ping tests are disabled when running
1193 under the Perl distribution since one cannot assume one or more
1194 of the following: enabled echo port at localhost, full Internet
1195 connectivity, or sympathetic firewalls. You can set the environment
1196 variable PERL_TEST_Net_Ping to "1" (one) before running the Perl test
1197 suite to enable all the Net::Ping tests.
1201 POSIX::sigaction() is now much more flexible and robust.
1202 You can now install coderef handlers, 'DEFAULT', and 'IGNORE'
1203 handlers, installing new handlers was not atomic.
1207 In Safe the C<%INC> now localised in a Safe compartment so that
1212 In SDBM_File on dosish platforms, some keys went missing because of
1213 lack of support for files with "holes". A workaround for the problem
1218 In Search::Dict one can now have a pre-processing hook for the
1219 lines being searched.
1223 The Shell module now has an OO interface.
1227 In Sys::Syslog there is now a failover mechanism that will go
1228 through alternative connection mechanisms until the message
1229 is successfully logged.
1233 The Test module has been significantly enhanced.
1237 Time::Local::timelocal() does not handle fractional seconds anymore.
1238 The rationale is that neither does localtime(), and timelocal() and
1239 localtime() are supposed to be inverses of each other.
1243 The vars pragma now supports declaring fully qualified variables.
1244 (Something that C<our()> does not and will not support.)
1248 The C<utf8::> name space (as in the pragma) provides various
1249 Perl-callable functions to provide low level access to Perl's
1250 internal Unicode representation. At the moment only length()
1251 has been implemented.
1255 =head1 Utility Changes
1261 Emacs perl mode (emacs/cperl-mode.el) has been updated to version
1266 F<emacs/e2ctags.pl> is now much faster.
1270 C<enc2xs> is a tool for people adding their own encodings to the
1275 C<h2ph> now supports C trigraphs.
1279 C<h2xs> now produces a template README.
1283 C<h2xs> now uses C<Devel::PPort> for better portability between
1284 different versions of Perl.
1288 C<h2xs> uses the new L<ExtUtils::Constant> module which will affect
1289 newly created extensions that define constants. Since the new code is
1290 more correct (if you have two constants where the first one is a
1291 prefix of the second one, the first constant B<never> gets defined),
1292 less lossy (it uses integers for integer constant, as opposed to the
1293 old code that used floating point numbers even for integer constants),
1294 and slightly faster, you might want to consider regenerating your
1295 extension code (the new scheme makes regenerating easy).
1296 L<h2xs> now also supports C trigraphs.
1300 C<libnetcfg> has been added to configure the libnet.
1304 C<perlbug> is now much more robust. It also sends the bug report to
1305 perl.org, not perl.com.
1309 C<perlcc> has been rewritten and its user interface (that is,
1310 command line) is much more like that of the UNIX C compiler, cc.
1311 (The perlbc tools has been removed. Use C<perlcc -B> instead.)
1312 B<Note that perlcc is still considered very experimental and
1317 C<perlivp> is a new Installation Verification Procedure utility
1318 for running any time after installing Perl.
1322 C<piconv> is an implementation of the character conversion utility
1323 C<iconv>, demonstrating the new Encode module.
1327 C<pod2html> now allows specifying a cache directory.
1331 C<pod2html> now produces XHTML 1.0.
1335 C<pod2html> now understands POD written using different line endings
1336 (PC-like CRLF versus UNIX-like LF versus MacClassic-like CR).
1340 C<s2p> has been completely rewritten in Perl. (It is in fact a full
1341 implementation of sed in Perl: you can use the sed functionality by
1342 using the C<psed> utility.)
1346 C<xsubpp> now understands POD documentation embedded in the *.xs files.
1350 C<xsubpp> now supports OUT keyword.
1354 =head1 New Documentation
1360 perl56delta details the changes between the 5.005 release and the
1365 perlclib documents the internal replacements for standard C library
1366 functions. (Interesting only for extension writers and Perl core
1371 perldebtut is a Perl debugging tutorial.
1375 perlebcdic contains considerations for running Perl on EBCDIC platforms.
1379 perlintro is a gentle introduction to Perl.
1383 perliol documents the internals of PerlIO with layers.
1387 perlmodstyle is a style guide for writing modules.
1391 perlnewmod tells about writing and submitting a new module.
1395 perlpacktut is a pack() tutorial.
1399 perlpod has been rewritten to be clearer and to record the best
1400 practices gathered over the years.
1404 perlpodspec is a more formal specification of the pod format,
1405 mainly of interest for writers of pod applications, not to
1406 people writing in pod.
1410 perlretut is a regular expression tutorial.
1414 perlrequick is a regular expressions quick-start guide.
1415 Yes, much quicker than perlretut.
1419 perltodo has been updated.
1423 perltootc has been renamed as perltooc (to not to conflict
1424 with perltoot in filesystems restricted to "8.3" names)
1428 perluniintro is an introduction to using Unicode in Perl.
1429 (perlunicode is more of a detailed reference and background
1434 perlutil explains the command line utilities packaged with the Perl
1439 The following platform-specific documents are available before
1440 the installation as README.I<platform>, and after the installation
1443 perlaix perlamiga perlapollo perlbeos perlbs2000
1444 perlce perlcygwin perldgux perldos perlepoc perlhpux
1445 perlhurd perlmachten perlmacos perlmint perlmpeix
1446 perlnetware perlos2 perlos390 perlplan9 perlqnx perlsolaris
1447 perltru64 perluts perlvmesa perlvms perlvos perlwin32
1453 The documentation for the POSIX-BC platform is called "BS2000", to avoid
1454 confusion with the Perl POSIX module.
1458 The documentation for the WinCE platform is called perlce (README.ce
1459 in the source code kit), to avoid confusion with the perlwin32
1460 documentation on 8.3-restricted filesystems.
1464 =head1 Performance Enhancements
1470 map() could get pathologically slow when the result list it generates
1471 is larger than the source list. The performance has been improved for
1476 sort() has been changed to use primarily mergesort internally as
1477 opposed to the earlier quicksort. For very small lists this may
1478 result in slightly slower sorting times, but in general the speedup
1479 should be at least 20%. Additional bonuses are that the worst case
1480 behaviour of sort() is now better (in computer science terms it now
1481 runs in time O(N log N), as opposed to quicksort's Theta(N**2)
1482 worst-case run time behaviour), and that sort() is now stable
1483 (meaning that elements with identical keys will stay ordered as they
1484 were before the sort). See the C<sort> pragma for information.
1486 The story in more detail: suppose you want to serve yourself a little
1489 @digits = ( 3,1,4,1,5,9 );
1491 A numerical sort of the digits will yield (1,1,3,4,5,9), as expected.
1492 Which C<1> comes first is hard to know, since one C<1> looks pretty
1493 much like any other. You can regard this as totally trivial,
1494 or somewhat profound. However, if you just want to sort the even
1495 digits ahead of the odd ones, then what will
1497 sort { ($a % 2) <=> ($b % 2) } @digits;
1499 yield? The only even digit, C<4>, will come first. But how about
1500 the odd numbers, which all compare equal? With the quicksort algorithm
1501 used to implement Perl 5.6 and earlier, the order of ties is left up
1502 to the sort. So, as you add more and more digits of Pi, the order
1503 in which the sorted even and odd digits appear will change.
1504 and, for sufficiently large slices of Pi, the quicksort algorithm
1505 in Perl 5.8 won't return the same results even if reinvoked with the
1506 same input. The justification for this rests with quicksort's
1507 worst case behavior. If you run
1509 sort { $a <=> $b } ( 1 .. $N , 1 .. $N );
1511 (something you might approximate if you wanted to merge two sorted
1512 arrays using sort), doubling $N doesn't just double the quicksort time,
1513 it I<quadruples> it. Quicksort has a worst case run time that can
1514 grow like N**2, so-called I<quadratic> behaviour, and it can happen
1515 on patterns that may well arise in normal use. You won't notice this
1516 for small arrays, but you I<will> notice it with larger arrays,
1517 and you may not live long enough for the sort to complete on arrays
1518 of a million elements. So the 5.8 quicksort scrambles large arrays
1519 before sorting them, as a statistical defence against quadratic behaviour.
1520 But that means if you sort the same large array twice, ties may be
1521 broken in different ways.
1523 Because of the unpredictability of tie-breaking order, and the quadratic
1524 worst-case behaviour, quicksort was I<almost> replaced completely with
1525 a stable mergesort. I<Stable> means that ties are broken to preserve
1526 the original order of appearance in the input array. So
1528 sort { ($a % 2) <=> ($b % 2) } (3,1,4,1,5,9);
1530 will yield (4,3,1,1,5,9), guaranteed. The even and odd numbers
1531 appear in the output in the same order they appeared in the input.
1532 Mergesort has worst case O(NlogN) behaviour, the best value
1533 attainable. And, ironically, this mergesort does particularly
1534 well where quicksort goes quadratic: mergesort sorts (1..$N, 1..$N)
1535 in O(N) time. But quicksort was rescued at the last moment because
1536 it is faster than mergesort on certain inputs and platforms.
1537 For example, if you really I<don't> care about the order of even
1538 and odd digits, quicksort will run in O(N) time; it's very good
1539 at sorting many repetitions of a small number of distinct elements.
1540 The quicksort divide and conquer strategy works well on platforms
1541 with relatively small, very fast, caches. Eventually, the problem gets
1542 whittled down to one that fits in the cache, from which point it
1543 benefits from the increased memory speed.
1545 Quicksort was rescued by implementing a sort pragma to control aspects
1546 of the sort. The B<stable> subpragma forces stable behaviour,
1547 regardless of algorithm. The B<_quicksort> and B<_mergesort>
1548 subpragmas are heavy-handed ways to select the underlying implementation.
1549 The leading C<_> is a reminder that these subpragmas may not survive
1550 beyond 5.8. More appropriate mechanisms for selecting the implementation
1551 exist, but they wouldn't have arrived in time to save quicksort.
1555 Hashes now use Bob Jenkins "One-at-a-Time" hashing key algorithm
1556 ( http://burtleburtle.net/bob/hash/doobs.html ). This algorithm is
1557 reasonably fast while producing a much better spread of values than
1558 the old hashing algorithm (originally by Chris Torek, later tweaked by
1559 Ilya Zakharevich). Hash values output from the algorithm on a hash of
1560 all 3-char printable ASCII keys comes much closer to passing the
1561 DIEHARD random number generation tests. According to perlbench, this
1562 change has not affected the overall speed of Perl.
1566 unshift() should now be noticeably faster.
1570 =head1 Installation and Configuration Improvements
1572 =head2 Generic Improvements
1578 INSTALL now explains how you can configure Perl to use 64-bit
1579 integers even on non-64-bit platforms.
1583 Policy.sh policy change: if you are reusing a Policy.sh file
1584 (see INSTALL) and you use Configure -Dprefix=/foo/bar and in the old
1585 Policy $prefix eq $siteprefix and $prefix eq $vendorprefix, all of
1586 them will now be changed to the new prefix, /foo/bar. (Previously
1587 only $prefix changed.) If you do not like this new behaviour,
1588 specify prefix, siteprefix, and vendorprefix explicitly.
1592 A new optional location for Perl libraries, otherlibdirs, is available.
1593 It can be used for example for vendor add-ons without disturbing Perl's
1594 own library directories.
1598 In many platforms the vendor-supplied 'cc' is too stripped-down to
1599 build Perl (basically, 'cc' doesn't do ANSI C). If this seems
1600 to be the case and 'cc' does not seem to be the GNU C compiler
1601 'gcc', an automatic attempt is made to find and use 'gcc' instead.
1605 gcc needs to closely track the operating system release to avoid
1606 build problems. If Configure finds that gcc was built for a different
1607 operating system release than is running, it now gives a clearly visible
1608 warning that there may be trouble ahead.
1612 Since Perl 5.8 is not binary-compatible with previous releases
1613 of Perl, Configure no longer suggests including the 5.005
1618 Configure C<-S> can now run non-interactively.
1622 Configure support for pdp11-style memory models has been removed due
1627 configure.gnu now works with options with whitespace in them.
1631 installperl now outputs everything to STDERR.
1635 Because PerlIO is now the default on most platforms, "-perlio" doesn't
1636 get appended to the $Config{archname} (also known as $^O) anymore.
1637 Instead, if you explicitly choose not to use perlio (Configure command
1638 line option -Uuseperlio), you will get "-stdio" appended.
1642 Another change related to the architecture name is that "-64all"
1643 (-Duse64bitall, or "maximally 64-bit") is appended only if your
1644 pointers are 64 bits wide. (To be exact, the use64bitall is ignored.)
1648 In AFS installations one can configure the root of the AFS to be
1649 somewhere else than the default F</afs> by using the Configure
1650 parameter C<-Dafsroot=/some/where/else>.
1654 APPLLIB_EXP, a less-know configuration-time definition, has been
1655 documented. It can be used to prepend site-specific directories
1656 to Perl's default search path (@INC), see INSTALL for information.
1660 The version of Berkeley DB used when the Perl (and, presumably, the
1661 DB_File extension) was built is now available as
1662 C<@Config{qw(db_version_major db_version_minor db_version_patch)}>
1663 from Perl and as C<DB_VERSION_MAJOR_CFG DB_VERSION_MINOR_CFG
1664 DB_VERSION_PATCH_CFG> from C.
1668 Building Berkeley DB3 for compatibility modes for DB, NDBM, and ODBM
1669 has been documented in INSTALL.
1673 If you have CPAN access (either network or a local copy such as a
1674 CD-ROM) you can during specify extra modules to Configure to build and
1675 install with Perl using the -Dextras=... option. See INSTALL for
1680 In addition to config.over a new override file, config.arch, is
1681 available. That is supposed to be used by hints file writers for
1682 architecture-wide changes (as opposed to config.over which is for
1687 If your file system supports symbolic links you can build Perl outside
1688 of the source directory by
1690 mkdir /tmp/perl/build/directory
1691 cd /tmp/perl/build/directory
1692 sh /path/to/perl/source/Configure -Dmksymlinks ...
1694 This will create in /tmp/perl/build/directory a tree of symbolic links
1695 pointing to files in /path/to/perl/source. The original files are left
1696 unaffected. After Configure has finished you can just say
1700 and Perl will be built and tested, all in /tmp/perl/build/directory.
1704 For Perl developers several new make targets for profiling
1705 and debugging have been added, see L<perlhack>.
1711 Use of the F<gprof> tool to profile Perl has been documented in
1712 L<perlhack>. There is a make target called "perl.gprof" for
1713 generating a gprofiled Perl executable.
1717 If you have GCC 3, there is a make target called "perl.gcov" for
1718 creating a gcoved Perl executable for coverage analysis. See
1723 If you are on IRIX or Tru64 platforms, new profiling/debugging options
1724 have been added, see L<perlhack> for more information about pixie and
1731 Guidelines of how to construct minimal Perl installations have
1732 been added to INSTALL.
1736 The Thread extension is now not built at all under ithreads
1737 (C<Configure -Duseithreads>) because it wouldn't work anyway (the
1738 Thread extension requires being Configured with C<-Duse5005threads>).
1740 But note that the Thread.pm interface is now shared by both
1745 The Gconvert macro ($Config{d_Gconvert}) used by perl for stringifying
1746 floating-point numbers is now more picky about using sprintf %.*g
1747 rules for the conversion. Some platforms that used to use gcvt may
1748 now resort to the slower sprintf.
1752 The obsolete method of making a special (e.g., debugging) flavor
1755 make LIBPERL=libperld.a
1757 has been removed. Use -DDEBUGGING instead.
1761 =head2 New Or Improved Platforms
1763 For the list of platforms known to support Perl,
1764 see L<perlport/"Supported Platforms">.
1770 AIX dynamic loading should be now better supported.
1774 AIX should now work better with gcc, threads, and 64-bitness. Also the
1775 long doubles support in AIX should be better now. See L<perlaix>.
1779 AtheOS ( http://www.atheos.cx/ ) is a new platform.
1783 BeOS has been reclaimed.
1787 DG/UX platform now supports the 5.005-style threads. See L<perldgux>.
1791 DYNIX/ptx platform (a.k.a. dynixptx) is supported at or near osvers 4.5.2.
1795 EBCDIC platforms (z/OS, also known as OS/390, POSIX-BC, and VM/ESA)
1796 have been regained. Many test suite tests still fail and the
1797 co-existence of Unicode and EBCDIC isn't quite settled, but the
1798 situation is much better than with Perl 5.6. See L<perlos390>,
1799 L<perlbs2000> (for POSIX-BC), and L<perlvmesa> for more information.
1803 Building perl with -Duseithreads or -Duse5005threads now works under
1804 HP-UX 10.20 (previously it only worked under 10.30 or later). You will
1805 need a thread library package installed. See README.hpux.
1809 MacOS Classic (MacPerl has of course been available since
1810 perl 5.004 but now the source code bases of standard Perl
1811 and MacPerl have been synchronised)
1815 MacOS X (or Darwin) should now be able to build Perl even on HFS+
1816 filesystems. (The case-insensitivity confused the Perl build process.)
1820 NCR MP-RAS is now supported.
1824 All the NetBSD specific patches (except for the installation
1825 specific ones) have been merged back to the main distribution.
1829 NetWare from Novell is now supported. See L<perlnetware>.
1833 NonStop-UX is now supported.
1837 NEC SUPER-UX is now supported.
1841 All the OpenBSD specific patches (except for the installation
1842 specific ones) have been merged back to the main distribution.
1846 Perl has been tested with the GNU pth userlevel thread package
1847 ( http://www.gnu.org/software/pth/pth.html ) . All but one thread
1848 test worked, and that one failure was because of test results arriving
1849 in unexpected order.
1853 Stratus VOS is now supported using Perl's native build method
1854 (Configure). This is the recommended method to build Perl on
1855 VOS. The older methods, which build miniperl, are still
1856 available. See L<perlvos>.
1860 Amdahl UTS UNIX mainframe platform is now supported.
1864 WinCE is now supported. See L<perlce>.
1868 z/OS (formerly known as OS/390, formerly known as MVS OE) has now
1869 support for dynamic loading. This is not selected by default,
1870 however, you must specify -Dusedl in the arguments of Configure.
1874 =head1 Selected Bug Fixes
1876 Numerous memory leaks and uninitialized memory accesses have been
1877 hunted down. Most importantly anonymous subs used to leak quite
1884 The autouse pragma didn't work for Multi::Part::Function::Names.
1888 caller() could cause core dumps in certain situations. Carp was sometimes
1889 affected by this problem. In particular, caller() now returns a
1890 subroutine name of C<(unknown)> for subroutines that have been removed
1891 from the symbol table.
1895 chop(@list) in list context returned the characters chopped in
1896 reverse order. This has been reversed to be in the right order.
1900 Configure no longer includes the DBM libraries (dbm, gdbm, db, ndbm)
1901 when building the Perl binary. The only exception to this is SunOS 4.x,
1906 The behaviour of non-decimal but numeric string constants such as
1907 "0x23" was platform-dependent: in some platforms that was seen as 35,
1908 in some as 0, in some as a floating point number (don't ask). This
1909 was caused by Perl using the operating system libraries in a situation
1910 where the result of the string to number conversion is undefined: now
1911 Perl consistently handles such strings as zero in numeric contexts.
1915 The order of DESTROYs has been made more predictable.
1919 Several debugger fixes: exit code now reflects the script exit code,
1920 condition C<"0"> now treated correctly, the C<d> command now checks
1921 line number, the C<$.> no longer gets corrupted, all debugger output
1922 now goes correctly to the socket if RemotePort is set.
1926 Perl 5.6.0 could emit spurious warnings about redefinition of dl_error()
1927 when statically building extensions into perl. This has been corrected.
1931 L<dprofpp> -R didn't work.
1935 C<*foo{FORMAT}> now works.
1939 Infinity is now recognized as a number.
1943 UNIVERSAL::isa no longer caches methods incorrectly. (This broke
1944 the Tk extension with 5.6.0.)
1948 Lexicals I: lexicals outside an eval "" weren't resolved
1949 correctly inside a subroutine definition inside the eval "" if they
1950 were not already referenced in the top level of the eval""ed code.
1954 Lexicals II: lexicals leaked at file scope into subroutines that
1955 were declared before the lexicals.
1959 Lexical warnings now propagating correctly between scopes
1960 and into C<eval "...">.
1964 C<use warnings qw(FATAL all)> did not work as intended. This has been
1969 warnings::enabled() now reports the state of $^W correctly if the caller
1970 isn't using lexical warnings.
1974 Line renumbering with eval and C<#line> now works.
1978 Fixed numerous memory leaks, especially in eval "".
1982 Localised tied variables no more leak memory
1985 tie my %tied_hash => 'Tie::StdHash';
1989 # Used to leak memory every time local() was called,
1990 # in a loop this added up.
1991 local($tied_hash{Foo}) = 1;
1995 Localised hash elements (and %ENV) are correctly unlocalised to not to
1996 exist, if that's what they were.
2000 tie my %tied_hash => 'Tie::StdHash';
2004 # Nothing has set the FOO element so far
2006 { local $tied_hash{FOO} = 'Bar' }
2008 # Here the FOO element would have been C<undef>,
2011 As a side effect of this fix, tied hash interfaces B<must> define
2012 the EXISTS and DELETE methods.
2016 mkdir() now ignores trailing slashes in the directory name,
2017 as mandated by POSIX.
2021 Some versions of glibc have a broken modfl(). This affects builds
2022 with C<-Duselongdouble>. This version of Perl detects this brokenness
2023 and has a workaround for it. The glibc release 2.2.2 is known to have
2024 fixed the modfl() bug.
2028 Modulus of unsigned numbers now works (4063328477 % 65535 used to
2029 return 27406, instead of 27047).
2033 Some "not a number" warnings introduced in 5.6.0 eliminated to be
2034 more compatible with 5.005. Infinity is now recognised as a number.
2038 Numeric conversions did not recognize changes in the string value
2039 properly in certain circumstances.
2043 Attributes (like :shared) didn't work with our().
2047 our() variables will not cause "will not stay shared" warnings.
2051 "our" variables of the same name declared in two sibling blocks
2052 resulted in bogus warnings about "redeclaration" of the variables.
2053 The problem has been corrected.
2057 pack "Z" now correctly terminates the string with "\0".
2061 Fix password routines which in some shadow password platforms
2062 (e.g. HP-UX) caused getpwent() to return every other entry.
2066 The PERL5OPT environment variable (for passing command line arguments
2067 to Perl) didn't work for more than a single group of options.
2071 PERL5OPT with embedded spaces didn't work.
2075 printf() no longer resets the numeric locale to "C".
2079 C<qw(a\\b)> now parses correctly as C<'a\\b'>.
2083 pos() did not return the correct value within s///ge in earlier
2084 versions. This is now handled correctly.
2088 Printing quads (64-bit integers) with printf/sprintf now works
2089 without the q L ll prefixes (assuming you are on a quad-capable platform).
2093 Regular expressions on references and overloaded scalars now work.
2097 Right-hand side magic (GMAGIC) could in many cases such as string
2098 concatenation be invoked too many times.
2102 scalar() now forces scalar context even when used in void context.
2106 SOCKS support is now much more robust.
2110 sort() arguments are now compiled in the right wantarray context
2111 (they were accidentally using the context of the sort() itself).
2112 The comparison block is now run in scalar context, and the arguments
2113 to be sorted are always provided list context.
2117 Changed the POSIX character class C<[[:space:]]> to include the (very
2118 rarely used) vertical tab character. Added a new POSIX-ish character
2119 class C<[[:blank:]]> which stands for horizontal whitespace
2120 (currently, the space and the tab).
2124 The tainting behaviour of sprintf() has been rationalized. It does
2125 not taint the result of floating point formats anymore, making the
2126 behaviour consistent with that of string interpolation.
2130 Some cases of inconsistent taint propagation (such as within hash
2131 values) have been fixed.
2135 The RE engine found in Perl 5.6.0 accidentally pessimised certain kinds
2136 of simple pattern matches. These are now handled better.
2140 Regular expression debug output (whether through C<use re 'debug'>
2141 or via C<-Dr>) now looks better.
2145 Multi-line matches like C<"a\nxb\n" =~ /(?!\A)x/m> were flawed. The
2150 Use of $& could trigger a core dump under some situations. This
2155 The regular expression captured submatches ($1, $2, ...) are now
2156 more consistently unset if the match fails, instead of leaving false
2157 data lying around in them.
2161 readline() on files opened in "slurp" mode could return an extra "" at
2162 the end in certain situations. This has been corrected.
2166 Autovivification of symbolic references of special variables described
2167 in L<perlvar> (as in C<${$num}>) was accidentally disabled. This works
2172 Sys::Syslog ignored the C<LOG_AUTH> constant.
2176 All but the first argument of the IO syswrite() method are now optional.
2180 $AUTOLOAD, sort(), lock(), and spawning subprocesses
2181 in multiple threads simultaneously are now thread-safe.
2185 Tie::ARRAY SPLICE method was broken.
2189 Allow read-only string on left hand side of non-modifying tr///.
2193 If C<STDERR> is tied, warnings caused by C<warn> and C<die> now
2194 correctly pass to it.
2198 Several Unicode fixes.
2204 BOMs (byte order marks) in the beginning of Perl files
2205 (scripts, modules) should now be transparently skipped.
2206 UTF-16 (UCS-2) encoded Perl files should now be read correctly.
2210 The character tables have been updated to Unicode 3.2.0.
2214 Comparing with utf8 data does not magically upgrade non-utf8 data
2215 into utf8. (This was a problem for example if you were mixing data
2216 from I/O and Unicode data: your output might have got magically encoded
2221 Generating illegal Unicode code points like U+FFFE, or the UTF-16
2222 surrogates, now also generates an optional warning.
2226 C<IsAlnum>, C<IsAlpha>, and C<IsWord> now match titlecase.
2230 Concatenation with the C<.> operator or via variable interpolation,
2231 C<eq>, C<substr>, C<reverse>, C<quotemeta>, the C<x> operator,
2232 substitution with C<s///>, single-quoted UTF8, should now work.
2236 The C<tr///> operator now works. Note that the C<tr///CU>
2237 functionality has been removed (but see pack('U0', ...)).
2241 C<eval "v200"> now works.
2245 Perl 5.6.0 parsed m/\x{ab}/ incorrectly, leading to spurious warnings.
2246 This has been corrected.
2250 Zero entries were missing from the Unicode classes like C<IsDigit>.
2256 Large unsigned numbers (those above 2**31) could sometimes lose their
2257 unsignedness, causing bogus results in arithmetic operations.
2261 =head2 Platform Specific Changes and Fixes
2269 Perl now works on post-4.0 BSD/OSes.
2275 Setting C<$0> now works (as much as possible; see L<perlvar> for details).
2281 Numerous updates; currently synchronised with Cygwin 1.3.10.
2285 Previously DYNIX/ptx had problems in its Configure probe for non-blocking I/O.
2291 EPOC update after Perl 5.6.0. See README.epoc.
2297 Perl now works on post-3.0 FreeBSDs.
2303 README.hpux updated; C<Configure -Duse64bitall> now works;
2304 now uses HP-UX malloc instead of Perl malloc.
2310 Numerous compilation flag and hint enhancements; accidental mixing
2311 of 32-bit and 64-bit libraries (a doomed attempt) made much harder.
2321 Long doubles should now work (see INSTALL).
2325 Linux previously had problems related to sockaddrlen when using
2326 accept(), revcfrom() (in Perl: recv()), getpeername(), and getsockname().
2334 Compilation of the standard Perl distribution in MacOS Classic should
2335 now work if you have the Metrowerks development environment and
2336 the missing Mac-specific toolkit bits. Contact the macperl mailing
2343 MPE/iX update after Perl 5.6.0. See README.mpeix.
2347 NetBSD/threads: try installing the GNU pth (should be in the
2348 packages collection, or http://www.gnu.org/software/pth/),
2349 and Configure with -Duseithreads.
2355 Perl now works on NetBSD/sparc.
2361 Now works with usethreads (see INSTALL).
2367 64-bitness using the Sun Workshop compiler now works.
2373 The native build method requires at least VOS Release 14.5.0
2374 and GNU C++/GNU Tools 2.0.1 or later. The Perl pack function
2375 now maps overflowed values to +infinity and underflowed values
2380 Tru64 (aka Digital UNIX, aka DEC OSF/1)
2382 The operating system version letter now recorded in $Config{osvers}.
2383 Allow compiling with gcc (previously explicitly forbidden). Compiling
2384 with gcc still not recommended because buggy code results, even with
2391 Fixed various alignment problems that lead into core dumps either
2392 during build or later; no longer dies on math errors at runtime;
2393 now using full quad integers (64 bits), previously was using
2394 only 46 bit integers for speed.
2400 chdir() now works better despite a CRT bug; now works with MULTIPLICITY
2401 (see INSTALL); now works with Perl's malloc.
2403 The tainting of C<%ENV> elements via C<keys> or C<values> was previously
2404 unimplemented. It now works as documented.
2406 The C<waitpid> emulation has been improved. The worst bug (now fixed)
2407 was that a pid of -1 would cause a wildcard search of all processes on
2410 POSIX-style signals are now emulated much better on VMS versions prior
2413 The C<system> function and backticks operator have improved
2414 functionality and better error handling.
2416 File access tests now use current process privileges rather than the
2417 user's default privileges, which could sometimes result in a mismatch
2418 between reported access and actual access.
2420 There is a new C<kill> implementation based on C<sys$sigprc> that allows
2421 older VMS systems (pre-7.0) to use C<kill> to send signals rather than
2422 simply force exit. This implementation also allows later systems to
2423 call C<kill> from within a signal handler.
2425 Iterative logical name translations are now limited to 10 iterations in
2426 imitation of SHOW LOGICAL and other OpenVMS facilities.
2436 accept() no longer leaks memory.
2440 Borland C++ v5.5 is now a supported compiler that can build Perl.
2441 However, the generated binaries continue to be incompatible with those
2442 generated by the other supported compilers (GCC and Visual C++).
2446 Better chdir() return value for a non-existent directory.
2450 Duping socket handles with open(F, ">&MYSOCK") now works under Windows 9x.
2454 New %ENV entries now propagate to subprocesses.
2458 Current directory entries in %ENV are now correctly propagated to child
2463 $ENV{LIB} now used to search for libs under Visual C.
2467 fork() emulation has been improved in various ways, but still continues
2468 to be experimental. See L<perlfork> for known bugs and caveats.
2472 A failed (pseudo)fork now returns undef and sets errno to EAGAIN.
2476 Win32::GetCwd() correctly returns C:\ instead of C: when at the drive root.
2477 Other bugs in chdir() and Cwd::cwd() have also been fixed.
2481 HTML files will be installed in c:\perl\html instead of c:\perl\lib\pod\html
2485 The makefiles now provide a single switch to bulk-enable all the features
2486 enabled in ActiveState ActivePerl (a popular Win32 binary distribution).
2490 Allow REG_EXPAND_SZ keys in the registry.
2494 Can now send() from all threads, not just the first one.
2498 Fake signal handling reenabled, bugs and all.
2502 %SIG has been enabled under USE_ITHREADS, but its use is completely
2503 unsupported under all configurations.
2507 Less stack reserved per thread so that more threads can run
2508 concurrently. (Still 16M per thread.)
2512 C<< File::Spec->tmpdir() >> now prefers C:/temp over /tmp
2513 (works better when perl is running as service).
2517 Better UNC path handling under ithreads.
2521 wait(), waitpid() and backticks now return the correct exit status under
2526 Win64 compilation is now supported.
2530 winsock handle leak fixed.
2534 The Perl parser has been stress tested using both random input and
2535 Markov chain input and the few found crashes and lockups have been
2542 =head1 New or Changed Diagnostics
2548 The lexical warnings category "deprecated" is no longer a sub-category
2549 of the "syntax" category. It is now a top-level category in its own
2554 All regular expression compilation error messages are now hopefully
2555 easier to understand both because the error message now comes before
2556 the failed regex and because the point of failure is now clearly
2557 marked by a C<E<lt>-- HERE> marker.
2561 The various "opened only for", "on closed", "never opened" warnings
2562 drop the C<main::> prefix for filehandles in the C<main> package,
2563 for example C<STDIN> instead of C<main::STDIN>.
2567 The "Unrecognized escape" warning has been extended to include C<\8>,
2568 C<\9>, and C<\_>. There is no need to escape any of the C<\w> characters.
2572 Two new debugging options have been added: if you have compiled your
2573 Perl with debugging, you can use the -DT and -DR options to trace
2574 tokenising and to add reference counts to displaying variables,
2579 The debugger (perl5db.pl) has been modified to present a more
2580 consistent commands interface, via (CommandSet=580). perl5db.t was
2581 also added to test the changes, and as a placeholder for further tests.
2587 The debugger has a new C<dumpDepth> option to control the maximum
2588 depth to which nested structures are dumped. The C<x> command has
2589 been extended so that C<x N EXPR> dumps out the value of I<EXPR> to a
2590 depth of at most I<N> levels.
2594 The debugger can now show lexical variables if you have the CPAN
2595 module PadWalker installed.
2599 If an attempt to use a (non-blessed) reference as an array index
2600 is made, a warning is given.
2604 C<push @a;> and C<unshift @a;> (with no values to push or unshift)
2605 now give a warning. This may be a problem for generated and evaled
2610 If you try to L<perlfunc/pack> a number less than 0 or larger than 255
2611 using the C<"C"> format you will get an optional warning. Similarly
2612 for the C<"c"> format and a number less than -128 or more than 127.
2616 Certain regex modifiers such as C<(?o)> make sense only if applied to
2617 the entire regex. You will get an optional warning if you try to do
2622 Using arrays or hashes as references (e.g. C<< %foo->{bar} >>
2623 has been deprecated for a while. Now you will get an optional warning.
2627 Using C<sort> in scalar context now issues an optional warning.
2628 This didn't do anything useful, as the sort was not performed.
2632 =head1 Changed Internals
2638 perlapi.pod (a companion to perlguts) now attempts to document the
2643 You can now build a really minimal perl called microperl.
2644 Building microperl does not require even running Configure;
2645 C<make -f Makefile.micro> should be enough. Beware: microperl makes
2646 many assumptions, some of which may be too bold; the resulting
2647 executable may crash or otherwise misbehave in wondrous ways.
2648 For careful hackers only.
2652 Added rsignal(), whichsig(), do_join(), op_clear, op_null,
2653 ptr_table_clear(), ptr_table_free(), sv_setref_uv(), and several UTF-8
2654 interfaces to the publicised API. For the full list of the available
2655 APIs see L<perlapi>.
2659 Made possible to propagate customised exceptions via croak()ing.
2663 Now xsubs can have attributes just like subs. (Well, at least the
2664 built-in attributes.)
2668 dTHR and djSP have been obsoleted; the former removed (because it's
2669 a no-op) and the latter replaced with dSP.
2673 PERL_OBJECT has been completely removed.
2677 The MAGIC constants (e.g. C<'P'>) have been macrofied
2678 (e.g. C<PERL_MAGIC_TIED>) for better source code readability
2679 and maintainability.
2683 The regex compiler now maintains a structure that identifies nodes in
2684 the compiled bytecode with the corresponding syntactic features of the
2685 original regex expression. The information is attached to the new
2686 C<offsets> member of the C<struct regexp>. See L<perldebguts> for more
2687 complete information.
2691 The C code has been made much more C<gcc -Wall> clean. Some warning
2692 messages still remain in some platforms, so if you are compiling with
2693 gcc you may see some warnings about dubious practices. The warnings
2694 are being worked on.
2698 F<perly.c>, F<sv.c>, and F<sv.h> have now been extensively commented.
2702 Documentation on how to use the Perl source repository has been added
2703 to F<Porting/repository.pod>.
2707 There are now several profiling make targets.
2711 =head1 Security Vulnerability Closed
2713 (This change was already made in 5.7.0 but bears repeating here.)
2715 A potential security vulnerability in the optional suidperl component
2716 of Perl was identified in August 2000. suidperl is neither built nor
2717 installed by default. As of November 2001 the only known vulnerable
2718 platform is Linux, most likely all Linux distributions. CERT and
2719 various vendors and distributors have been alerted about the vulnerability.
2720 See http://www.cpan.org/src/5.0/sperl-2000-08-05/sperl-2000-08-05.txt
2721 for more information.
2723 The problem was caused by Perl trying to report a suspected security
2724 exploit attempt using an external program, /bin/mail. On Linux
2725 platforms the /bin/mail program had an undocumented feature which
2726 when combined with suidperl gave access to a root shell, resulting in
2727 a serious compromise instead of reporting the exploit attempt. If you
2728 don't have /bin/mail, or if you have 'safe setuid scripts', or if
2729 suidperl is not installed, you are safe.
2731 The exploit attempt reporting feature has been completely removed from
2732 Perl 5.8.0 (and the maintenance release 5.6.1, and it was removed also
2733 from all the Perl 5.7 releases), so that particular vulnerability
2734 isn't there anymore. However, further security vulnerabilities are,
2735 unfortunately, always possible. The suidperl functionality is most
2736 probably going to be removed in Perl 5.10. In any case, suidperl
2737 should only be used by security experts who know exactly what they are
2738 doing and why they are using suidperl instead of some other solution
2739 such as sudo ( see http://www.courtesan.com/sudo/ ).
2743 Several new tests have been added, especially for the F<lib> and F<ext>
2744 subsections. There are now about 65 000 individual tests (spread over
2745 about 700 test scripts), in the regression suite (5.6.1 has about
2746 11700 tests, in 258 test scripts) Many of the new tests are of course
2747 introduced by the new modules, but still in general Perl is now more
2750 Because of the large number of tests, running the regression suite
2751 will take considerably longer time than it used to: expect the suite
2752 to take up to 4-5 times longer to run than in perl 5.6. In a really
2753 fast machine you can hope to finish the suite in about 6-8 minutes
2756 The tests are now reported in a different order than in earlier Perls.
2757 (This happens because the test scripts from under t/lib have been moved
2758 to be closer to the library/extension they are testing.)
2760 =head1 Known Problems
2768 In AIX 4.2 Perl extensions that use C++ functions that use statics
2769 may have problems in that the statics are not getting initialized.
2770 In newer AIX releases this has been solved by linking Perl with
2771 the libC_r library, but unfortunately in AIX 4.2 the said library
2772 has an obscure bug where the various functions related to time
2773 (such as time() and gettimeofday()) return broken values, and
2774 therefore in AIX 4.2 Perl is not linked against the libC_r.
2778 vac 5.0.0.0 May Produce Buggy Code For Perl
2780 The AIX C compiler vac version 5.0.0.0 may produce buggy code,
2781 resulting in few random tests failing, but when the failing tests
2782 are run by hand, they succeed. We suggest upgrading to at least
2783 vac version 5.0.1.0, that has been known to compile Perl correctly.
2784 "lslpp -L|grep vac.C" will tell you the vac version. See README.aix.
2788 If building threaded Perl, you may get compilation warning from pp_sys.c:
2790 "pp_sys.c", line 4651.39: 1506-280 (W) Function argument assignment between types "unsigned char*" and "const void*" is not allowed.
2792 This is harmless; it is caused by the getnetbyaddr() and getnetbyaddr_r()
2793 having slightly different types for their first argument.
2799 The following tests fail on 5.8.0 Perl in BeOS Personal 5.03:
2801 t/op/lfs............................FAILED at test 17
2802 t/op/magic..........................FAILED at test 24
2803 ext/Fcntl/t/syslfs..................FAILED at test 17
2804 ext/File/Glob/t/basic...............FAILED at test 3
2805 ext/POSIX/t/sigaction...............FAILED at test 13
2806 ext/POSIX/t/waitpid.................FAILED at test 1
2807 lib/Tie/File/t/16_handle............FAILED at test 39
2809 See L<perlbeos> (README.beos) for more details.
2811 =head2 ext/threads/t/libc
2813 If this test fails, it indicates that your libc (C library) is not
2814 threadsafe. This particular test stress tests the localtime() call to
2815 find out whether it is threadsafe. See L<perlthrtut> for more information.
2817 =head2 FreeBSD Failing locale Test 117 For ISO8859-15 Locales
2819 The ISO8859-15 locales may fail the locale test 117 in FreeBSD.
2820 This is caused by the characters \xFF (y with diaeresis) and \xBE
2821 (Y with diaeresis) not behaving correctly when being matched
2824 =head2 Modifying $_ Inside for(..)
2828 works without complaint. It shouldn't. (You should be able to
2829 modify only lvalue elements inside the loops.) You can see the
2830 correct behaviour by replacing the 1..5 with 1, 2, 3, 4, 5.
2832 =head2 mod_perl 1.26 Doesn't Build With Threaded Perl
2834 Use mod_perl 1.27 or higher.
2836 =head2 lib/ftmp-security tests warn 'system possibly insecure'
2838 Don't panic. Read INSTALL 'make test' section instead.
2840 =head2 HP-UX lib/posix Subtest 9 Fails When LP64-Configured
2842 If perl is configured with -Duse64bitall, the successful result of the
2843 subtest 10 of lib/posix may arrive before the successful result of the
2844 subtest 9, which confuses the test harness so much that it thinks the
2847 =head2 Linux With Sfio Fails op/misc Test 48
2853 Please remember to set your environment variable LC_ALL to "C"
2854 (setenv LC_ALL C) before running "make test" to avoid a lot of
2855 warnings about the broken locales of Mac OS X.
2857 The following tests are known to fail:
2859 Failed Test Stat Wstat Total Fail Failed List of Failed
2860 -------------------------------------------------------------------------
2861 ../ext/DB_File/t/db-btree.t 0 11 ?? ?? % ??
2862 ../ext/DB_File/t/db-recno.t 149 3 2.01% 61 63 65
2864 If you are building on a UFS partition, you will also probably see
2865 t/op/stat.t subtest #9 fail. This is caused by Darwin's UFS not
2866 supporting inode change time.
2868 Also the ext/POSIX/t/posix.t subtest #10 fails but it is skipped for
2869 now because the failure is Apple's fault, not Perl's (blocked signals
2872 If you Configure with ithreads, ext/threads/t/libc.t will fail, again
2873 not Perl's fault-- the libc of Mac OS X is not threadsafe (in this
2874 particular test the localtime() call is found to be threadunsafe.)
2876 =head2 op/sprintf tests 91, 129, and 130
2878 The op/sprintf tests 91, 129, and 130 are known to fail on some platforms.
2879 Examples include any platform using sfio, and Compaq/Tandem's NonStop-UX.
2881 The test 91 is known to fail at QNX6 (nto), because C<sprintf '%e',0>
2882 incorrectly produces C<0.000000e+0> instead of C<0.000000e+00>.
2884 For the tests 129 and 130 the failing platforms do not comply with
2885 the ANSI C Standard, line 19ff on page 134 of ANSI X3.159 1989 to
2886 be exact. (They produce something other than "1" and "-1" when
2887 formatting 0.6 and -0.6 using the printf format "%.0f", most often
2888 they produce "0" and "-0".)
2892 In case you are still using Solaris 2.5 (aka SunOS 5.5), you may
2893 experience failures (the test core dumping) in lib/locale.t.
2894 The suggested cure is to upgrade your Solaris.
2898 When Perl is built using the native build process on VOS Release
2899 14.5.0 and GNU C++/GNU Tools 2.0.1, all attempted tests either
2900 pass or result in TODO (ignored) failures.
2902 =head2 Term::ReadKey not working on Win32
2904 Use Term::ReadKey 2.20 or later.
2906 =head2 Failure of Thread (5.005-style) tests
2908 B<Note that support for 5.005-style threading is deprecated,
2909 experimental and practically unsupported. In 5.10 it is expected
2912 The following tests are known to fail due to fundamental problems in
2913 the 5.005 threading implementation. These are not new failures--Perl
2914 5.005_0x has the same bugs, but didn't have these tests.
2916 ../ext/List/Util/t/first.t 255 65280 7 4 57.14% 2 5-7
2917 ../lib/English.t 2 512 54 2 3.70% 2-3
2918 ../lib/Filter/Simple/t/data.t 6 3 50.00% 1-3
2919 ../lib/Filter/Simple/t/filter_onl 9 3 33.33% 1-2 5
2920 ../lib/autouse.t 10 1 10.00% 4
2921 op/flip.t 15 1 6.67% 15
2923 These failures are unlikely to get fixed as the 5.005-style threads
2924 are considered fundamentally broken. (Basically what happens is that
2925 competing threads can corrupt shared global state.)
2929 ../lib/Math/Trig.t 26 1 3.85% 25
2930 ../lib/warnings.t 470 1 0.21% 429
2932 The Trig.t failure is caused by the slighly differing (from IEEE)
2933 floating point implementation of UNICOS. The warnings.t failure is
2934 also related: the test assumes a certain floating point output format,
2935 this assumption fails in UNICOS.
2943 During Configure the test
2945 Guessing which symbols your C compiler and preprocessor define...
2947 will probably fail with error messages like
2949 CC-20 cc: ERROR File = try.c, Line = 3
2950 The identifier "bad" is undefined.
2952 bad switch yylook 79bad switch yylook 79bad switch yylook 79bad switch yylook 79#ifdef A29K
2955 CC-65 cc: ERROR File = try.c, Line = 3
2956 A semicolon is expected at this point.
2958 This is caused by a bug in awk utility of UNICOS/mk. You can ignore
2959 the error, but it does cause a slight problem: you cannot fully
2960 benefit from the h2ph utility (see L<h2ph>) that can be used to
2961 convert C headers to Perl libraries, mainly used to be able to access
2962 from Perl the constants defined using C preprocessor, cpp. Because of
2963 the above error parts of the converted headers will be invisible.
2964 Luckily, these days the need for h2ph is rare.
2968 If building Perl with the interpreter threads (ithreads), the
2969 getgrent(), getgrnam(), and getgrgid() functions cannot return the
2970 list of the group members due to a bug in the multithreaded support of
2971 UNICOS/mk. What this means that in list context the functions will
2972 return only three values, not four.
2978 There are a few known test failures, see L<perluts>.
2982 There should be no reported test failures with a default configuration,
2983 though there are a number of tests marked TODO that point to areas
2984 needing further debugging and/or porting work.
2988 In multi-CPU boxes there are some problems with the I/O buffering:
2989 some output may appear twice.
2991 =head2 XML::Parser not working
2993 Use XML::Parser 2.31 or later.
2995 =head2 z/OS (OS/390)
2997 z/OS has rather many test failures but the situation is actually
2998 better than it was in 5.6.0, it's just that so many new modules and
2999 tests have been added.
3001 Failed Test Stat Wstat Total Fail Failed List of Failed
3002 ---------------------------------------------------------------------------
3003 ../ext/Data/Dumper/t/dumper.t 357 8 2.24% 311 314 325 327
3005 ../ext/IO/lib/IO/t/io_unix.t 5 4 80.00% 2-5
3006 ../ext/Storable/t/downgrade.t 12 3072 169 12 7.10% 14-15 46-47 78-79
3008 ../lib/ExtUtils/t/Constant.t 121 30976 48 48 100.00% 1-48
3009 ../lib/ExtUtils/t/Embed.t 9 9 100.00% 1-9
3010 op/pat.t 910 7 0.77% 665 776 785 832-
3012 op/sprintf.t 224 3 1.34% 98 100 136
3013 op/tr.t 97 5 5.15% 63 71-74
3014 uni/fold.t 780 6 0.77% 61 169 196 661
3017 The dumper.t and downgrade.t are problems in the tests, the io_unix
3018 and sprintf are problems in the USS (UDP sockets and printf formats).
3019 The pat, tr, and fold are genuine Perl problems caused by EBCDIC (and
3020 in the pat and fold cases, combining that with Unicode). The Constant
3021 and Embed are probably problems in the tests (since they test Perl's
3022 ability to build extensions, and that seems to be working reasonably well.)
3024 =head2 Localising Tied Arrays and Hashes Is Broken
3028 doesn't work as one would expect: the old value is restored
3031 =head2 Self-tying of Arrays and Hashes Is Forbidden
3033 Self-tying of arrays and hashes is broken in rather deep and
3034 hard-to-fix ways. As a stop-gap measure to avoid people from getting
3035 frustrated at the mysterious results (core dumps, most often) it is
3036 for now forbidden (you will get a fatal error even from an attempt).
3038 =head2 Building Extensions Can Fail Because Of Largefiles
3040 Some extensions like mod_perl are known to have issues with
3041 `largefiles', a change brought by Perl 5.6.0 in which file offsets
3042 default to 64 bits wide, where supported. Modules may fail to compile
3043 at all or compile and work incorrectly. Currently there is no good
3044 solution for the problem, but Configure now provides appropriate
3045 non-largefile ccflags, ldflags, libswanted, and libs in the %Config
3046 hash (e.g., $Config{ccflags_nolargefiles}) so the extensions that are
3047 having problems can try configuring themselves without the
3048 largefileness. This is admittedly not a clean solution, and the
3049 solution may not even work at all. One potential failure is whether
3050 one can (or, if one can, whether it's a good idea) link together at
3051 all binaries with different ideas about file offsets, all this is
3054 =head2 Unicode Support on EBCDIC Still Spotty
3056 Though mostly working, Unicode support still has problem spots on
3057 EBCDIC platforms. One such known spot are the C<\p{}> and C<\P{}>
3058 regular expression constructs for code points less than 256: the
3059 C<pP> are testing for Unicode code points, not knowing about EBCDIC.
3061 =head2 The Compiler Suite Is Still Very Experimental
3063 The compiler suite is slowly getting better but it continues to be
3064 highly experimental. Use in production environments is discouraged.
3066 =head2 The Long Double Support Is Still Experimental
3068 The ability to configure Perl's numbers to use "long doubles",
3069 floating point numbers of hopefully better accuracy, is still
3070 experimental. The implementations of long doubles are not yet
3071 widespread and the existing implementations are not quite mature
3072 or standardised, therefore trying to support them is a rare
3073 and moving target. The gain of more precision may also be offset
3074 by slowdown in computations (more bits to move around, and the
3075 operations are more likely to be executed by less optimised
3078 =head2 Seen In Perl 5.7 But Gone Now
3080 C<Time::Piece> (previously known as C<Time::Object>) was removed
3081 because it was felt that it didn't have enough value in it to be a
3082 core module. It is still a useful module, though, and is available
3085 Perl 5.8 unfortunately does not build anymore on AmigaOS,
3086 this broke at some point accidentally. Since there are not that many
3087 Amiga developers available, we could not get this fixed and tested in
3090 =head1 Reporting Bugs
3092 If you find what you think is a bug, you might check the articles
3093 recently posted to the comp.lang.perl.misc newsgroup and the perl
3094 bug database at http://bugs.perl.org/ There may also be
3095 information at http://www.perl.com/ , the Perl Home Page.
3097 If you believe you have an unreported bug, please run the B<perlbug>
3098 program included with your release. Be sure to trim your bug down
3099 to a tiny but sufficient test case. Your bug report, along with the
3100 output of C<perl -V>, will be sent off to perlbug@perl.org to be
3101 analysed by the Perl porting team.
3105 The F<Changes> file for exhaustive details on what changed.
3107 The F<INSTALL> file for how to build Perl.
3109 The F<README> file for general stuff.
3111 The F<Artistic> and F<Copying> files for copyright information.
3115 Written by Jarkko Hietaniemi <F<jhi@iki.fi>>.