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 The existing behaviour when localising tied arrays and hashes is wrong,
273 and will be changed in a future release, so do not rely on the existing
274 behaviour. See L<"Localising Tied Arrays and Hashes Is Broken">.
278 =head1 Core Enhancements
280 =head2 PerlIO is Now The Default
286 IO is now by default done via PerlIO rather than system's "stdio".
287 PerlIO allows "layers" to be "pushed" onto a file handle to alter the
288 handle's behaviour. Layers can be specified at open time via 3-arg
291 open($fh,'>:crlf :utf8', $path) || ...
293 or on already opened handles via extended C<binmode>:
295 binmode($fh,':encoding(iso-8859-7)');
297 The built-in layers are: unix (low level read/write), stdio (as in
298 previous Perls), perlio (re-implementation of stdio buffering in a
299 portable manner), crlf (does CRLF <=> "\n" translation as on Win32,
300 but available on any platform). A mmap layer may be available if
301 platform supports it (mostly UNIXes).
303 Layers to be applied by default may be specified via the 'open' pragma.
305 See L</"Installation and Configuration Improvements"> for the effects
306 of PerlIO on your architecture name.
310 File handles can be marked as accepting Perl's internal encoding of Unicode
311 (UTF-8 or UTF-EBCDIC depending on platform) by a pseudo layer ":utf8" :
313 open($fh,">:utf8","Uni.txt");
315 Note for EBCDIC users: the pseudo layer ":utf8" is erroneously named
316 for you since it's not UTF-8 what you will be getting but instead
317 UTF-EBCDIC. See L<perlunicode>, L<utf8>, and
318 http://www.unicode.org/unicode/reports/tr16/ for more information.
319 In future releases this naming may change.
323 File handles can translate character encodings from/to Perl's internal
324 Unicode form on read/write via the ":encoding()" layer.
328 File handles can be opened to "in memory" files held in Perl scalars via:
330 open($fh,'>', \$variable) || ...
334 Anonymous temporary files are available without need to
335 'use FileHandle' or other module via
337 open($fh,"+>", undef) || ...
339 That is a literal undef, not an undefined value.
343 The list form of C<open> is now implemented for pipes (at least on UNIX):
345 open($fh,"-|", 'cat', '/etc/motd')
347 creates a pipe, and runs the equivalent of exec('cat', '/etc/motd') in
352 If your locale environment variables (LANGUAGE, LC_ALL, LC_CTYPE, LANG)
353 contain the strings 'UTF-8' or 'UTF8' (case-insensitive matching),
354 the default encoding of your STDIN, STDOUT, and STDERR, and of
355 B<any subsequent file open>, is UTF-8.
359 =head2 Restricted Hashes
361 A restricted hash is restricted to a certain set of keys, no keys
362 outside the set can be added. Also individual keys can be restricted
363 so that the key cannot be deleted and the value cannot be changed.
364 No new syntax is involved: the Hash::Util module is the interface.
368 Perl used to be fragile in that signals arriving at inopportune moments
369 could corrupt Perl's internal state. Now Perl postpones handling of
370 signals until it's safe (between opcodes).
372 This change may have surprising side effects because signals no longer
373 interrupt Perl instantly. Perl will now first finish whatever it was
374 doing, like finishing an internal operation (like sort()) or an
375 external operation (like an I/O operation), and only then look at any
376 arrived signals (and before starting the next operation). No more corrupt
377 internal state since the current operation is always finished first,
378 but the signal may take more time to get heard. Note that breaking
379 out from potentially blocking operations should still work, though.
381 =head2 Unicode Overhaul
383 Unicode in general should be now much more usable than in Perl 5.6.0
384 (or even in 5.6.1). Unicode can be used in hash keys, Unicode in
385 regular expressions should work now, Unicode in tr/// should work now,
386 Unicode in I/O should work now. See L<perluniintro> for introduction
387 and L<perlunicode> for details.
393 The Unicode Character Database coming with Perl has been upgraded
394 to Unicode 3.2.0. For more information, see http://www.unicode.org/ .
398 For developers interested in enhancing Perl's Unicode capabilities:
399 almost all the UCD files are included with the Perl distribution in
400 the F<lib/unicore> subdirectory. The most notable omission, for space
401 considerations, is the Unihan database.
405 The properties \p{Blank} and \p{SpacePerl} have been added. "Blank" is like
406 C isblank(), that is, it contains only "horizontal whitespace" (the space
407 character is, the newline isn't), and the "SpacePerl" is the Unicode
408 equivalent of C<\s> (\p{Space} isn't, since that includes the vertical
409 tabulator character, whereas C<\s> doesn't.)
411 See "New Unicode Properties" earlier in this document for additional
412 information on changes with Unicode properties.
416 =head2 Understanding of Numbers
418 In general a lot of fixing has happened in the area of Perl's
419 understanding of numbers, both integer and floating point. Since in
420 many systems the standard number parsing functions like C<strtoul()>
421 and C<atof()> seem to have bugs, Perl tries to work around their
422 deficiencies. This results hopefully in more accurate numbers.
424 Perl now tries internally to use integer values in numeric conversions
425 and basic arithmetics (+ - * /) if the arguments are integers, and
426 tries also to keep the results stored internally as integers.
427 This change leads to often slightly faster and always less lossy
428 arithmetics. (Previously Perl always preferred floating point numbers
431 =head2 Miscellaneous Changes
437 AUTOLOAD is now lvaluable, meaning that you can add the :lvalue attribute
438 to AUTOLOAD subroutines and you can assign to the AUTOLOAD return value.
442 The $Config{byteorder} (and corresponding BYTEORDER in config.h) was
443 previously wrong in platforms if sizeof(long) was 4, but sizeof(IV)
444 was 8. The byteorder was only sizeof(long) bytes long (1234 or 4321),
445 but now it is correctly sizeof(IV) bytes long, (12345678 or 87654321).
446 (This problem didn't affect Windows platforms.)
448 Also, $Config{byteorder} is now computed dynamically--this is more
449 robust with "fat binaries" where an executable image contains binaries
450 for more than one binary platform, and when cross-compiling.
454 C<perl -d:Module=arg,arg,arg> now works (previously one couldn't pass
455 in multiple arguments.)
459 The builtin dump() now gives an optional warning
460 C<dump() better written as CORE::dump()>,
461 meaning that by default C<dump(...)> is resolved as the builtin
462 dump() which dumps core and aborts, not as (possibly) user-defined
463 C<sub dump>. To call the latter, qualify the call as C<&dump(...)>.
464 (The whole dump() feature is to considered deprecated, and possibly
465 removed/changed in future releases.)
469 chomp() and chop() are now overridable. Note, however, that their
470 prototype (as given by C<prototype("CORE::chomp")> is undefined,
471 because it cannot be expressed and therefore one cannot really write
472 replacements to override these builtins.
476 END blocks are now run even if you exit/die in a BEGIN block.
477 Internally, the execution of END blocks is now controlled by
478 PL_exit_flags & PERL_EXIT_DESTRUCT_END. This enables the new
479 behaviour for Perl embedders. This will default in 5.10. See
484 Formats now support zero-padded decimal fields.
488 Lvalue subroutines can now return C<undef> in list context.
489 However, the lvalue subroutine feature still remains experimental.
493 A lost warning "Can't declare ... dereference in my" has been
494 restored (Perl had it earlier but it became lost in later releases.)
498 A new special regular expression variable has been introduced:
499 C<$^N>, which contains the most-recently closed group (submatch).
503 C<no Module;> now works even if there is no "sub unimport" in the Module.
507 The numerical comparison operators return C<undef> if either operand
508 is a NaN. Previously the behaviour was unspecified.
512 The following builtin functions are now overridable: each(), keys(),
513 pop(), push(), shift(), splice(), unshift().
517 C<pack() / unpack()> now can group template letters with C<()> and then
518 apply repetition/count modifiers on the groups.
522 C<pack() / unpack()> can now process the Perl internal numeric types:
523 IVs, UVs, NVs-- and also long doubles, if supported by the platform.
524 The template letters are C<j>, C<J>, C<F>, and C<D>.
528 C<pack('U0a*', ...)> can now be used to force a string to UTF8.
532 my __PACKAGE__ $obj now works.
536 POSIX::sleep() now returns the number of I<unslept> seconds
537 (as the POSIX standard says), as opposed to CORE::sleep() which
538 returns the number of slept seconds.
542 The printf() and sprintf() now support parameter reordering using the
543 C<%\d+\$> and C<*\d+\$> syntaxes. For example
545 print "%2\$s %1\$s\n", "foo", "bar";
547 will print "bar foo\n". This feature helps in writing
548 internationalised software, and in general when the order
549 of the parameters can vary.
553 prototype(\&) is now available.
557 prototype(\[$@%&]) is now available to implicitly create references
558 (useful for example if you want to emulate the tie() interface).
562 A new command-line option, C<-t> is available. It is the
563 little brother of C<-T>: instead of dying on taint violations,
564 lexical warnings are given. B<This is only meant as a temporary
565 debugging aid while securing the code of old legacy applications.
566 This is not a substitute for -T.>
570 In other taint news, the C<exec LIST> and C<system LIST> have now been
571 considered too risky (think C<exec @ARGV>: it can start any program
572 with any arguments), and now the said forms cause a warning.
573 You should carefully launder the arguments to guarantee their
574 validity. In future releases of Perl the forms will become fatal
575 errors so consider starting laundering now.
579 Tied hash interfaces are now required to have the EXISTS and DELETE
580 methods (either own or inherited).
584 If tr/// is just counting characters, it doesn't attempt to
589 untie() will now call an UNTIE() hook if it exists. See L<perltie>
594 L<utime> now supports C<utime undef, undef, @files> to change the
595 file timestamps to the current time.
599 The rules for allowing underscores (underbars) in numeric constants
600 have been relaxed and simplified: now you can have an underscore
601 simply B<between digits>.
605 Rather than relying on C's argv[0] (which may not contain a full pathname)
606 where possible $^X is now set by asking the operating system.
607 (eg by reading F</proc/self/exe> on Linux, F</proc/curproc/file> on FreeBSD)
611 A new variable, C<${^TAINT}>, indicates whether taint mode is enabled.
615 You can now override the readline() builtin, and this overrides also
616 the <FILEHANDLE> angle bracket operator.
620 The command-line options -s and -F are now recognized on the shebang
625 Use of the C</c> match modifier without an accompanying C</g> modifier
626 elicits a new warning: C<Use of /c modifier is meaningless without /g>.
628 Use of C</c> in substitutions, even with C</g>, elicits
629 C<Use of /c modifier is meaningless in s///>.
631 Use of C</g> with C<split> elicits C<Use of /g modifier is meaningless
636 =head1 Modules and Pragmata
638 =head2 New Modules and Pragmata
644 C<Attribute::Handlers> allows a class to define attribute handlers.
647 use Attribute::Handlers;
648 sub Wolf :ATTR(SCALAR) { print "howl!\n" }
650 # later, in some package using or inheriting from MyPack...
652 my MyPack $Fluffy : Wolf; # the attribute handler Wolf will be called
654 Both variables and routines can have attribute handlers. Handlers can
655 be specific to type (SCALAR, ARRAY, HASH, or CODE), or specific to the
656 exact compilation phase (BEGIN, CHECK, INIT, or END).
657 See L<Attribute::Handlers>.
661 C<B::Concise> is a new compiler backend for walking the Perl syntax
662 tree, printing concise info about ops, from Stephen McCamant. The
663 output is highly customisable. See L<B::Concise>.
667 The new bignum, bigint, and bigrat pragmas implement transparent
668 bignum support (using the Math::BigInt, Math::BigFloat, and
669 Math::BigRat backends), by Tels.
673 C<Class::ISA> for reporting the search path for a class's ISA tree,
674 by Sean Burke, has been added. See L<Class::ISA>.
678 C<Cwd> has now a split personality: if possible, an XS extension is
679 used, (this will hopefully be faster, more secure, and more robust)
680 but if not possible, the familiar Perl implementation is used.
684 C<Devel::PPPort>, originally from Kenneth Albanowski and now
685 maintained by Paul Marquess, has been added. It is primarily used
686 by C<h2xs> to enhance portability of XS modules between different
687 versions of Perl. See L<Devel::PPPort>.
691 C<Digest>, frontend module for calculating digests (checksums), from
692 Gisle Aas, has been added. See L<Digest>.
696 C<Digest::MD5> for calculating MD5 digests (checksums) as defined in
697 RFC 1321, from Gisle Aas, has been added. See L<Digest::MD5>.
699 use Digest::MD5 'md5_hex';
701 $digest = md5_hex("Thirsty Camel");
703 print $digest, "\n"; # 01d19d9d2045e005c3f1b80e8b164de1
705 NOTE: the C<MD5> backward compatibility module is deliberately not
706 included since its further use is discouraged.
710 C<Encode>, orginally by Nick Ing-Simmons and now maintained by Dan
711 Kogai, provides a mechanism to translate between different character
712 encodings. Support for Unicode, ISO-8859-1, and ASCII are compiled in
713 to the module. Several other encodings (like the rest of the
714 ISO-8859, CP*/Win*, Mac, KOI8-R, three variants EBCDIC, Chinese,
715 Japanese, and Korean encodings) are included and can be loaded at
716 runtime. (For space considerations, the largest Chinese encodings
717 have been separated into their own CPAN module, Encode::HanExtra,
718 which Encode will use if available). See L<Encode>.
720 Any encoding supported by Encode module is also available to the
721 ":encoding()" layer if PerlIO is used.
725 C<Hash::Util> is the interface to the new I<restricted hashes>
726 feature. (Implemented by Jeffrey Friedl, Nick Ing-Simmons, and
727 Michael Schwern.) See L<Hash::Util>.
731 C<I18N::Langinfo> can be use to query locale information.
732 See L<I18N::Langinfo>.
736 C<I18N::LangTags> has functions for dealing with RFC3066-style
737 language tags, by Sean Burke. See L<I18N::LangTags>.
741 C<ExtUtils::Constant> is a new tool for extension writers for
742 generating XS code to import C header constants, by Nicholas Clark.
743 See L<ExtUtils::Constant>.
747 C<Filter::Simple> is an easy-to-use frontend to Filter::Util::Call,
748 from Damian Conway. See L<Filter::Simple>.
754 use Filter::Simple sub {
755 while (my ($from, $to) = splice @_, 0, 2) {
764 use MyFilter qr/red/ => 'green';
766 print "red\n"; # this code is filtered, will print "green\n"
767 print "bored\n"; # this code is filtered, will print "bogreen\n"
771 print "red\n"; # this code is not filtered, will print "red\n"
775 C<File::Temp> allows one to create temporary files and directories in
776 an easy, portable, and secure way, by Tim Jenness. See L<File::Temp>.
780 C<Filter::Util::Call> provides you with the framework to write
781 I<Source Filters> in Perl, from Paul Marquess. For most uses the
782 frontend Filter::Simple is to be preferred. See L<Filter::Util::Call>.
786 C<if> is a new pragma for conditional inclusion of modules, from
791 L<libnet> is a collection of perl5 modules related to network
792 programming, from Graham Barr. See L<Net::FTP>, L<Net::NNTP>,
793 L<Net::Ping> (not part of libnet, but related), L<Net::POP3>,
794 L<Net::SMTP>, and L<Net::Time>.
796 Perl installation leaves libnet unconfigured, use F<libnetcfg> to configure.
800 C<List::Util> is a selection of general-utility list subroutines, like
801 sum(), min(), first(), and shuffle(), by Graham Barr. See L<List::Util>.
805 C<Locale::Constants>, C<Locale::Country>, C<Locale::Currency>
806 C<Locale::Language>, and L<Locale::Script>, from Neil Bowers, have
807 been added. They provide the codes for various locale standards, such
808 as "fr" for France, "usd" for US Dollar, and "ja" for Japanese.
812 $country = code2country('jp'); # $country gets 'Japan'
813 $code = country2code('Norway'); # $code gets 'no'
815 See L<Locale::Constants>, L<Locale::Country>, L<Locale::Currency>,
816 and L<Locale::Language>.
820 C<Locale::Maketext> is localization framework from Sean Burke. See
821 L<Locale::Maketext>, and L<Locale::Maketext::TPJ13>. The latter is an
822 article about software localization, originally published in The Perl
823 Journal #13, republished here with kind permission.
827 C<Math::BigRat> for big rational numbers, to accompany Math::BigInt and
828 Math::BigFloat, from Tels. See L<Math::BigRat>.
832 C<Memoize> can make your functions faster by trading space for time,
833 from Mark-Jason Dominus. See L<Memoize>.
837 C<MIME::Base64> allows you to encode data in base64, from Gisle Aas,
838 as defined in RFC 2045 - I<MIME (Multipurpose Internet Mail
843 $encoded = encode_base64('Aladdin:open sesame');
844 $decoded = decode_base64($encoded);
846 print $encoded, "\n"; # "QWxhZGRpbjpvcGVuIHNlc2FtZQ=="
852 C<MIME::QuotedPrint> allows you to encode data in quoted-printable
853 encoding, as defined in RFC 2045 - I<MIME (Multipurpose Internet Mail
854 Extensions)>, from Gisle Aas.
856 use MIME::QuotedPrint;
858 $encoded = encode_qp("Smiley in Unicode: \x{263a}");
859 $decoded = decode_qp($encoded);
861 print $encoded, "\n"; # "Smiley in Unicode: =263A"
863 MIME::QuotedPrint has been enhanced to provide the basic methods
864 necessary to use it with PerlIO::Via as in :
866 use MIME::QuotedPrint;
867 open($fh,">Via(MIME::QuotedPrint)",$path);
869 See L<MIME::QuotedPrint>.
873 C<NEXT> is pseudo-class for method redispatch, from Damian Conway.
878 C<open> is a new pragma for setting the default I/O disciplines
883 C<PerlIO::Scalar> provides the implementation of IO to "in memory"
884 Perl scalars as discussed above, from Nick Ing-Simmons. It also
885 serves as an example of a loadable PerlIO layer. Other future
886 possibilities include PerlIO::Array and PerlIO::Code.
887 See L<PerlIO::Scalar>.
891 C<PerlIO::Via> acts as a PerlIO layer and wraps PerlIO layer
892 functionality provided by a class (typically implemented in perl
893 code), from Nick Ing-Simmons.
895 use MIME::QuotedPrint;
896 open($fh,">Via(MIME::QuotedPrint)",$path);
898 This will automatically convert everything output to C<$fh>
899 to Quoted-Printable. See L<PerlIO::Via>.
903 C<Pod::ParseLink>, by Russ Allbery, has been added,
904 to parse LZ<><> links in pods as described in the new
909 C<Pod::Text::Overstrike>, by Joe Smith, has been added.
910 It converts POD data to formatted overstrike text.
911 See L<Pod::Text::Overstrike>.
915 C<Scalar::Util> is a selection of general-utility scalar subroutines,
916 like blessed(), reftype(), and tainted(). See L<Scalar::Util>.
920 C<sort> is a new pragma for controlling the behaviour of sort().
924 C<Storable> gives persistence to Perl data structures by allowing the
925 storage and retrieval of Perl data to and from files in a fast and
926 compact binary format. Because in effect Storable does serialisation
927 of Perl data structues, with it you can also clone deep, hierarchical
928 datastructures. Storable was originally created by Raphael Manfredi,
929 but it is now maintained by Abhijit Menon-Sen. Storable has been
930 enhanced to understand the two new hash features, Unicode keys and
931 restricted hashes. See L<Storable>.
935 C<Switch>, from Damian Conway, has been added. Just by saying
939 you have C<switch> and C<case> available in Perl.
945 case 1 { print "number 1" }
946 case "a" { print "string a" }
947 case [1..10,42] { print "number in list" }
948 case (@array) { print "number in list" }
949 case /\w+/ { print "pattern" }
950 case qr/\w+/ { print "pattern" }
951 case (%hash) { print "entry in hash" }
952 case (\%hash) { print "entry in hash" }
953 case (\&sub) { print "arg to subroutine" }
954 else { print "previous case not true" }
961 C<Test::More> is yet another framework for writing test scripts,
962 more extensive than Test::Simple, by Michael Schwern. See L<Test::More>.
966 C<Test::Simple> has basic utilities for writing tests, by Michael
967 Schwern. See L<Test::Simple>.
971 C<Text::Balanced> has been added, for extracting delimited text
972 sequences from strings, from Damian Conway.
974 use Text::Balanced 'extract_delimited';
976 ($a, $b) = extract_delimited("'never say never', he never said", "'", '');
978 $a will be "'never say never'", $b will be ', he never said'.
980 In addition to extract_delimited() there are also extract_bracketed(),
981 extract_quotelike(), extract_codeblock(), extract_variable(),
982 extract_tagged(), extract_multiple(), gen_delimited_pat(), and
983 gen_extract_tagged(). With these you can implement rather advanced
984 parsing algorithms. See L<Text::Balanced>.
988 C<threads> is an interface to interpreter threads, by Arthur Bergman.
989 Interpreter threads (ithreads) is the new thread model introduced in
990 Perl 5.6 but only available as an internal interface for extension
991 writers (and for Win32 Perl for C<fork()> emulation). See L<threads>.
995 C<threads::shared> allows data sharing for interpreter threads, from
996 Arthur Bergman. In the ithreads model any data sharing between
997 threads must be explicit, as opposed to the old 5.005 thread model
998 where data sharing was implicit. See L<threads::shared>.
1002 C<Tie::File>, by Mark-Jason Dominus, associates a Perl array with the
1003 lines of a file, see L<Tie::File>.
1007 C<Tie::Memoize>, by Ilya Zakharevich, provides on-demand loaded hashes,
1008 see L<Tie::Memoize>.
1012 C<Tie::RefHash::Nestable>, by Edward Avis, allows storing hash
1013 references (unlike the standard Tie::RefHash) The module is contained
1014 within Tie::RefHash, see L<Tie::RefHash>.
1018 C<Time::HiRes> provides high resolution timing (ualarm, usleep,
1019 and gettimeofday), from Douglas E. Wegscheid. See L<Time::HiRes>.
1023 C<Unicode::UCD> offers a querying interface to the Unicode Character
1024 Database. See L<Unicode::UCD>.
1028 C<Unicode::Collate> implements the UCA (Unicode Collation Algorithm)
1029 for sorting Unicode strings, by SADAHIRO Tomoyuki. See L<Unicode::Collate>.
1033 C<Unicode::Normalize> implements the various Unicode normalization
1034 forms, by SADAHIRO Tomoyuki. See L<Unicode::Normalize>.
1038 C<XS::Typemap>, by Tim Jenness, is a test extension that exercises XS
1039 typemaps. Nothing gets installed but for extension writers the code
1044 =head2 Updated And Improved Modules and Pragmata
1050 The following independently supported modules have been updated to the
1051 newest versions from CPAN: CGI, CPAN, DB_File, File::Spec, File::Temp,
1052 Getopt::Long, Math::BigFloat, Math::BigInt, the podlators bundle
1053 (Pod::Man, Pod::Text), Pod::LaTeX, Pod::Parser, Storable,
1054 Term::ANSIColor, Test, Text-Tabs+Wrap.
1058 The attributes::reftype() now works on tied arguments.
1062 AutoLoader can now be disabled with C<no AutoLoader;>.
1066 B::Deparse has been significantly enhanced. It now can deparse almost
1067 all of the standard test suite (so that the tests still succeed).
1068 There is a make target "test.deparse" for trying this out.
1072 Class::Struct can now define the classes in compile time.
1076 Class::Struct now assigns the array/hash element if the accessor
1077 is called with an array/hash element as the B<sole> argument.
1081 The return value of Cwd::fastcwd() is now tainted.
1085 Data::Dumper has now an option to sort hashes.
1089 Data::Dumper has now an option to dump code references
1094 DB_File now supports newer Berkeley DB versions, among
1099 Devel::Peek now has an interface for the Perl memory statistics
1100 (this works only if you are using perl's malloc, and if you have
1101 compiled with debugging).
1105 The English module can now be used without the infamous performance
1108 use English '-no_match_vars';
1110 (Assuming, of course, that one doesn't need the troublesome variables
1111 C<$`>, C<$&>, or C<$'>.) Also, introduced C<@LAST_MATCH_START> and
1112 C<@LAST_MATCH_END> English aliases for C<@-> and C<@+>.
1116 ExtUtils::MakeMaker now uses File::Spec internally, which hopefully
1117 leads into better portability.
1121 Fcntl, Socket, and Sys::Syslog have been rewritten to use the
1122 new-style constant dispatch section (see L<ExtUtils::Constant>).
1123 This means that they will be more robust and hopefully faster.
1127 File::Find now chdir()s correctly when chasing symbolic links.
1131 File::Find now has pre- and post-processing callbacks. It also
1132 correctly changes directories when chasing symbolic links. Callbacks
1133 (naughtily) exiting with "next;" instead of "return;" now work.
1137 File::Find is now (again) reentrant. It also has been made
1142 The warnings issued by File::Find now belong to their own category.
1143 You can enable/disable them with C<use/no warnings 'File::Find';>.
1147 File::Glob::glob() renamed to File::Glob::bsd_glob() to avoid
1148 prototype mismatch with CORE::glob().
1152 File::Glob now supports C<GLOB_LIMIT> constant to limit the size of
1153 the returned list of filenames.
1157 IPC::Open3 now allows the use of numeric file descriptors.
1161 IO::Socket has now atmark() method, which returns true if the socket
1162 is positioned at the out-of-band mark. The method is also exportable
1163 as a sockatmark() function.
1167 IO::Socket::INET has support for ReusePort option (if your platform
1168 supports it). The Reuse option now has an alias, ReuseAddr. For clarity
1169 you may want to prefer ReuseAddr.
1173 IO::Socket::INET now supports C<LocalPort> of zero (usually meaning
1174 that the operating system will make one up.)
1178 use lib now works identically to @INC. Removing directories
1179 with 'no lib' now works.
1183 Math::BigFloat and Math::BigInt have undergone a full rewrite.
1184 They are now magnitudes faster, and they support various
1185 bignum libraries such as GMP and PARI as their backends.
1189 Math::Complex handles inf, NaN etc., better.
1193 Net::Ping has been muchly enhanced: multihoming is now supported,
1194 Win32 functionality is better, there is now time measuring
1195 functionality (optionally high-resolution using Time::HiRes),
1196 and there is now "external" protocol which uses Net::Ping::External
1197 module which runs your external ping utility and parses the output.
1198 A version of Net::Ping::External is available in CPAN.
1200 Note that some of the Net::Ping tests are disabled when running
1201 under the Perl distribution since one cannot assume one or more
1202 of the following: enabled echo port at localhost, full Internet
1203 connectivity, or sympathetic firewalls. You can set the environment
1204 variable PERL_TEST_Net_Ping to "1" (one) before running the Perl test
1205 suite to enable all the Net::Ping tests.
1209 POSIX::sigaction() is now much more flexible and robust.
1210 You can now install coderef handlers, 'DEFAULT', and 'IGNORE'
1211 handlers, installing new handlers was not atomic.
1215 In Safe the C<%INC> now localised in a Safe compartment so that
1220 In SDBM_File on dosish platforms, some keys went missing because of
1221 lack of support for files with "holes". A workaround for the problem
1226 In Search::Dict one can now have a pre-processing hook for the
1227 lines being searched.
1231 The Shell module now has an OO interface.
1235 In Sys::Syslog there is now a failover mechanism that will go
1236 through alternative connection mechanisms until the message
1237 is successfully logged.
1241 The Test module has been significantly enhanced.
1245 Time::Local::timelocal() does not handle fractional seconds anymore.
1246 The rationale is that neither does localtime(), and timelocal() and
1247 localtime() are supposed to be inverses of each other.
1251 The vars pragma now supports declaring fully qualified variables.
1252 (Something that C<our()> does not and will not support.)
1256 The C<utf8::> name space (as in the pragma) provides various
1257 Perl-callable functions to provide low level access to Perl's
1258 internal Unicode representation. At the moment only length()
1259 has been implemented.
1263 =head1 Utility Changes
1269 Emacs perl mode (emacs/cperl-mode.el) has been updated to version
1274 F<emacs/e2ctags.pl> is now much faster.
1278 C<enc2xs> is a tool for people adding their own encodings to the
1283 C<h2ph> now supports C trigraphs.
1287 C<h2xs> now produces a template README.
1291 C<h2xs> now uses C<Devel::PPort> for better portability between
1292 different versions of Perl.
1296 C<h2xs> uses the new L<ExtUtils::Constant> module which will affect
1297 newly created extensions that define constants. Since the new code is
1298 more correct (if you have two constants where the first one is a
1299 prefix of the second one, the first constant B<never> gets defined),
1300 less lossy (it uses integers for integer constant, as opposed to the
1301 old code that used floating point numbers even for integer constants),
1302 and slightly faster, you might want to consider regenerating your
1303 extension code (the new scheme makes regenerating easy).
1304 L<h2xs> now also supports C trigraphs.
1308 C<libnetcfg> has been added to configure the libnet.
1312 C<perlbug> is now much more robust. It also sends the bug report to
1313 perl.org, not perl.com.
1317 C<perlcc> has been rewritten and its user interface (that is,
1318 command line) is much more like that of the UNIX C compiler, cc.
1319 (The perlbc tools has been removed. Use C<perlcc -B> instead.)
1320 B<Note that perlcc is still considered very experimental and
1325 C<perlivp> is a new Installation Verification Procedure utility
1326 for running any time after installing Perl.
1330 C<piconv> is an implementation of the character conversion utility
1331 C<iconv>, demonstrating the new Encode module.
1335 C<pod2html> now allows specifying a cache directory.
1339 C<pod2html> now produces XHTML 1.0.
1343 C<pod2html> now understands POD written using different line endings
1344 (PC-like CRLF versus UNIX-like LF versus MacClassic-like CR).
1348 C<s2p> has been completely rewritten in Perl. (It is in fact a full
1349 implementation of sed in Perl: you can use the sed functionality by
1350 using the C<psed> utility.)
1354 C<xsubpp> now understands POD documentation embedded in the *.xs files.
1358 C<xsubpp> now supports OUT keyword.
1362 =head1 New Documentation
1368 perl56delta details the changes between the 5.005 release and the
1373 perlclib documents the internal replacements for standard C library
1374 functions. (Interesting only for extension writers and Perl core
1379 perldebtut is a Perl debugging tutorial.
1383 perlebcdic contains considerations for running Perl on EBCDIC platforms.
1387 perlintro is a gentle introduction to Perl.
1391 perliol documents the internals of PerlIO with layers.
1395 perlmodstyle is a style guide for writing modules.
1399 perlnewmod tells about writing and submitting a new module.
1403 perlpacktut is a pack() tutorial.
1407 perlpod has been rewritten to be clearer and to record the best
1408 practices gathered over the years.
1412 perlpodspec is a more formal specification of the pod format,
1413 mainly of interest for writers of pod applications, not to
1414 people writing in pod.
1418 perlretut is a regular expression tutorial.
1422 perlrequick is a regular expressions quick-start guide.
1423 Yes, much quicker than perlretut.
1427 perltodo has been updated.
1431 perltootc has been renamed as perltooc (to not to conflict
1432 with perltoot in filesystems restricted to "8.3" names)
1436 perluniintro is an introduction to using Unicode in Perl.
1437 (perlunicode is more of a detailed reference and background
1442 perlutil explains the command line utilities packaged with the Perl
1447 The following platform-specific documents are available before
1448 the installation as README.I<platform>, and after the installation
1451 perlaix perlamiga perlapollo perlbeos perlbs2000
1452 perlce perlcygwin perldgux perldos perlepoc perlhpux
1453 perlhurd perlmachten perlmacos perlmint perlmpeix
1454 perlnetware perlos2 perlos390 perlplan9 perlqnx perlsolaris
1455 perltru64 perluts perlvmesa perlvms perlvos perlwin32
1457 Eastern Asian Perl users are now welcomed in their own languages:
1458 README.jp (Japanese), README.ko (Korean), README.cn (simplified
1459 Chinese) and README.tw (traditional Chinese), which are written in
1460 normal pod but encoded in EUC-JP, EUC-KR, EUC-CN and Big5. These
1461 will get installed as
1463 perljp perlko perlcn perltw
1469 The documentation for the POSIX-BC platform is called "BS2000", to avoid
1470 confusion with the Perl POSIX module.
1474 The documentation for the WinCE platform is called perlce (README.ce
1475 in the source code kit), to avoid confusion with the perlwin32
1476 documentation on 8.3-restricted filesystems.
1480 =head1 Performance Enhancements
1486 map() could get pathologically slow when the result list it generates
1487 is larger than the source list. The performance has been improved for
1492 sort() has been changed to use primarily mergesort internally as
1493 opposed to the earlier quicksort. For very small lists this may
1494 result in slightly slower sorting times, but in general the speedup
1495 should be at least 20%. Additional bonuses are that the worst case
1496 behaviour of sort() is now better (in computer science terms it now
1497 runs in time O(N log N), as opposed to quicksort's Theta(N**2)
1498 worst-case run time behaviour), and that sort() is now stable
1499 (meaning that elements with identical keys will stay ordered as they
1500 were before the sort). See the C<sort> pragma for information.
1502 The story in more detail: suppose you want to serve yourself a little
1505 @digits = ( 3,1,4,1,5,9 );
1507 A numerical sort of the digits will yield (1,1,3,4,5,9), as expected.
1508 Which C<1> comes first is hard to know, since one C<1> looks pretty
1509 much like any other. You can regard this as totally trivial,
1510 or somewhat profound. However, if you just want to sort the even
1511 digits ahead of the odd ones, then what will
1513 sort { ($a % 2) <=> ($b % 2) } @digits;
1515 yield? The only even digit, C<4>, will come first. But how about
1516 the odd numbers, which all compare equal? With the quicksort algorithm
1517 used to implement Perl 5.6 and earlier, the order of ties is left up
1518 to the sort. So, as you add more and more digits of Pi, the order
1519 in which the sorted even and odd digits appear will change.
1520 and, for sufficiently large slices of Pi, the quicksort algorithm
1521 in Perl 5.8 won't return the same results even if reinvoked with the
1522 same input. The justification for this rests with quicksort's
1523 worst case behavior. If you run
1525 sort { $a <=> $b } ( 1 .. $N , 1 .. $N );
1527 (something you might approximate if you wanted to merge two sorted
1528 arrays using sort), doubling $N doesn't just double the quicksort time,
1529 it I<quadruples> it. Quicksort has a worst case run time that can
1530 grow like N**2, so-called I<quadratic> behaviour, and it can happen
1531 on patterns that may well arise in normal use. You won't notice this
1532 for small arrays, but you I<will> notice it with larger arrays,
1533 and you may not live long enough for the sort to complete on arrays
1534 of a million elements. So the 5.8 quicksort scrambles large arrays
1535 before sorting them, as a statistical defence against quadratic behaviour.
1536 But that means if you sort the same large array twice, ties may be
1537 broken in different ways.
1539 Because of the unpredictability of tie-breaking order, and the quadratic
1540 worst-case behaviour, quicksort was I<almost> replaced completely with
1541 a stable mergesort. I<Stable> means that ties are broken to preserve
1542 the original order of appearance in the input array. So
1544 sort { ($a % 2) <=> ($b % 2) } (3,1,4,1,5,9);
1546 will yield (4,3,1,1,5,9), guaranteed. The even and odd numbers
1547 appear in the output in the same order they appeared in the input.
1548 Mergesort has worst case O(NlogN) behaviour, the best value
1549 attainable. And, ironically, this mergesort does particularly
1550 well where quicksort goes quadratic: mergesort sorts (1..$N, 1..$N)
1551 in O(N) time. But quicksort was rescued at the last moment because
1552 it is faster than mergesort on certain inputs and platforms.
1553 For example, if you really I<don't> care about the order of even
1554 and odd digits, quicksort will run in O(N) time; it's very good
1555 at sorting many repetitions of a small number of distinct elements.
1556 The quicksort divide and conquer strategy works well on platforms
1557 with relatively small, very fast, caches. Eventually, the problem gets
1558 whittled down to one that fits in the cache, from which point it
1559 benefits from the increased memory speed.
1561 Quicksort was rescued by implementing a sort pragma to control aspects
1562 of the sort. The B<stable> subpragma forces stable behaviour,
1563 regardless of algorithm. The B<_quicksort> and B<_mergesort>
1564 subpragmas are heavy-handed ways to select the underlying implementation.
1565 The leading C<_> is a reminder that these subpragmas may not survive
1566 beyond 5.8. More appropriate mechanisms for selecting the implementation
1567 exist, but they wouldn't have arrived in time to save quicksort.
1571 Hashes now use Bob Jenkins "One-at-a-Time" hashing key algorithm
1572 ( http://burtleburtle.net/bob/hash/doobs.html ). This algorithm is
1573 reasonably fast while producing a much better spread of values than
1574 the old hashing algorithm (originally by Chris Torek, later tweaked by
1575 Ilya Zakharevich). Hash values output from the algorithm on a hash of
1576 all 3-char printable ASCII keys comes much closer to passing the
1577 DIEHARD random number generation tests. According to perlbench, this
1578 change has not affected the overall speed of Perl.
1582 unshift() should now be noticeably faster.
1586 =head1 Installation and Configuration Improvements
1588 =head2 Generic Improvements
1594 INSTALL now explains how you can configure Perl to use 64-bit
1595 integers even on non-64-bit platforms.
1599 Policy.sh policy change: if you are reusing a Policy.sh file
1600 (see INSTALL) and you use Configure -Dprefix=/foo/bar and in the old
1601 Policy $prefix eq $siteprefix and $prefix eq $vendorprefix, all of
1602 them will now be changed to the new prefix, /foo/bar. (Previously
1603 only $prefix changed.) If you do not like this new behaviour,
1604 specify prefix, siteprefix, and vendorprefix explicitly.
1608 A new optional location for Perl libraries, otherlibdirs, is available.
1609 It can be used for example for vendor add-ons without disturbing Perl's
1610 own library directories.
1614 In many platforms the vendor-supplied 'cc' is too stripped-down to
1615 build Perl (basically, 'cc' doesn't do ANSI C). If this seems
1616 to be the case and 'cc' does not seem to be the GNU C compiler
1617 'gcc', an automatic attempt is made to find and use 'gcc' instead.
1621 gcc needs to closely track the operating system release to avoid
1622 build problems. If Configure finds that gcc was built for a different
1623 operating system release than is running, it now gives a clearly visible
1624 warning that there may be trouble ahead.
1628 Since Perl 5.8 is not binary-compatible with previous releases
1629 of Perl, Configure no longer suggests including the 5.005
1634 Configure C<-S> can now run non-interactively.
1638 Configure support for pdp11-style memory models has been removed due
1643 configure.gnu now works with options with whitespace in them.
1647 installperl now outputs everything to STDERR.
1651 Because PerlIO is now the default on most platforms, "-perlio" doesn't
1652 get appended to the $Config{archname} (also known as $^O) anymore.
1653 Instead, if you explicitly choose not to use perlio (Configure command
1654 line option -Uuseperlio), you will get "-stdio" appended.
1658 Another change related to the architecture name is that "-64all"
1659 (-Duse64bitall, or "maximally 64-bit") is appended only if your
1660 pointers are 64 bits wide. (To be exact, the use64bitall is ignored.)
1664 In AFS installations one can configure the root of the AFS to be
1665 somewhere else than the default F</afs> by using the Configure
1666 parameter C<-Dafsroot=/some/where/else>.
1670 APPLLIB_EXP, a less-know configuration-time definition, has been
1671 documented. It can be used to prepend site-specific directories
1672 to Perl's default search path (@INC), see INSTALL for information.
1676 The version of Berkeley DB used when the Perl (and, presumably, the
1677 DB_File extension) was built is now available as
1678 C<@Config{qw(db_version_major db_version_minor db_version_patch)}>
1679 from Perl and as C<DB_VERSION_MAJOR_CFG DB_VERSION_MINOR_CFG
1680 DB_VERSION_PATCH_CFG> from C.
1684 Building Berkeley DB3 for compatibility modes for DB, NDBM, and ODBM
1685 has been documented in INSTALL.
1689 If you have CPAN access (either network or a local copy such as a
1690 CD-ROM) you can during specify extra modules to Configure to build and
1691 install with Perl using the -Dextras=... option. See INSTALL for
1696 In addition to config.over a new override file, config.arch, is
1697 available. That is supposed to be used by hints file writers for
1698 architecture-wide changes (as opposed to config.over which is for
1703 If your file system supports symbolic links you can build Perl outside
1704 of the source directory by
1706 mkdir /tmp/perl/build/directory
1707 cd /tmp/perl/build/directory
1708 sh /path/to/perl/source/Configure -Dmksymlinks ...
1710 This will create in /tmp/perl/build/directory a tree of symbolic links
1711 pointing to files in /path/to/perl/source. The original files are left
1712 unaffected. After Configure has finished you can just say
1716 and Perl will be built and tested, all in /tmp/perl/build/directory.
1720 For Perl developers several new make targets for profiling
1721 and debugging have been added, see L<perlhack>.
1727 Use of the F<gprof> tool to profile Perl has been documented in
1728 L<perlhack>. There is a make target called "perl.gprof" for
1729 generating a gprofiled Perl executable.
1733 If you have GCC 3, there is a make target called "perl.gcov" for
1734 creating a gcoved Perl executable for coverage analysis. See
1739 If you are on IRIX or Tru64 platforms, new profiling/debugging options
1740 have been added, see L<perlhack> for more information about pixie and
1747 Guidelines of how to construct minimal Perl installations have
1748 been added to INSTALL.
1752 The Thread extension is now not built at all under ithreads
1753 (C<Configure -Duseithreads>) because it wouldn't work anyway (the
1754 Thread extension requires being Configured with C<-Duse5005threads>).
1756 But note that the Thread.pm interface is now shared by both
1761 The Gconvert macro ($Config{d_Gconvert}) used by perl for stringifying
1762 floating-point numbers is now more picky about using sprintf %.*g
1763 rules for the conversion. Some platforms that used to use gcvt may
1764 now resort to the slower sprintf.
1768 The obsolete method of making a special (e.g., debugging) flavor
1771 make LIBPERL=libperld.a
1773 has been removed. Use -DDEBUGGING instead.
1777 =head2 New Or Improved Platforms
1779 For the list of platforms known to support Perl,
1780 see L<perlport/"Supported Platforms">.
1786 AIX dynamic loading should be now better supported.
1790 AIX should now work better with gcc, threads, and 64-bitness. Also the
1791 long doubles support in AIX should be better now. See L<perlaix>.
1795 AtheOS ( http://www.atheos.cx/ ) is a new platform.
1799 BeOS has been reclaimed.
1803 DG/UX platform now supports the 5.005-style threads. See L<perldgux>.
1807 DYNIX/ptx platform (a.k.a. dynixptx) is supported at or near osvers 4.5.2.
1811 EBCDIC platforms (z/OS, also known as OS/390, POSIX-BC, and VM/ESA)
1812 have been regained. Many test suite tests still fail and the
1813 co-existence of Unicode and EBCDIC isn't quite settled, but the
1814 situation is much better than with Perl 5.6. See L<perlos390>,
1815 L<perlbs2000> (for POSIX-BC), and L<perlvmesa> for more information.
1819 Building perl with -Duseithreads or -Duse5005threads now works under
1820 HP-UX 10.20 (previously it only worked under 10.30 or later). You will
1821 need a thread library package installed. See README.hpux.
1825 MacOS Classic (MacPerl has of course been available since
1826 perl 5.004 but now the source code bases of standard Perl
1827 and MacPerl have been synchronised)
1831 MacOS X (or Darwin) should now be able to build Perl even on HFS+
1832 filesystems. (The case-insensitivity confused the Perl build process.)
1836 NCR MP-RAS is now supported.
1840 All the NetBSD specific patches (except for the installation
1841 specific ones) have been merged back to the main distribution.
1845 NetWare from Novell is now supported. See L<perlnetware>.
1849 NonStop-UX is now supported.
1853 NEC SUPER-UX is now supported.
1857 All the OpenBSD specific patches (except for the installation
1858 specific ones) have been merged back to the main distribution.
1862 Perl has been tested with the GNU pth userlevel thread package
1863 ( http://www.gnu.org/software/pth/pth.html ) . All but one thread
1864 test worked, and that one failure was because of test results arriving
1865 in unexpected order.
1869 Stratus VOS is now supported using Perl's native build method
1870 (Configure). This is the recommended method to build Perl on
1871 VOS. The older methods, which build miniperl, are still
1872 available. See L<perlvos>.
1876 Amdahl UTS UNIX mainframe platform is now supported.
1880 WinCE is now supported. See L<perlce>.
1884 z/OS (formerly known as OS/390, formerly known as MVS OE) has now
1885 support for dynamic loading. This is not selected by default,
1886 however, you must specify -Dusedl in the arguments of Configure.
1890 =head1 Selected Bug Fixes
1892 Numerous memory leaks and uninitialized memory accesses have been
1893 hunted down. Most importantly anonymous subs used to leak quite
1900 The autouse pragma didn't work for Multi::Part::Function::Names.
1904 caller() could cause core dumps in certain situations. Carp was sometimes
1905 affected by this problem. In particular, caller() now returns a
1906 subroutine name of C<(unknown)> for subroutines that have been removed
1907 from the symbol table.
1911 chop(@list) in list context returned the characters chopped in
1912 reverse order. This has been reversed to be in the right order.
1916 Configure no longer includes the DBM libraries (dbm, gdbm, db, ndbm)
1917 when building the Perl binary. The only exception to this is SunOS 4.x,
1922 The behaviour of non-decimal but numeric string constants such as
1923 "0x23" was platform-dependent: in some platforms that was seen as 35,
1924 in some as 0, in some as a floating point number (don't ask). This
1925 was caused by Perl using the operating system libraries in a situation
1926 where the result of the string to number conversion is undefined: now
1927 Perl consistently handles such strings as zero in numeric contexts.
1931 The order of DESTROYs has been made more predictable.
1935 Several debugger fixes: exit code now reflects the script exit code,
1936 condition C<"0"> now treated correctly, the C<d> command now checks
1937 line number, the C<$.> no longer gets corrupted, all debugger output
1938 now goes correctly to the socket if RemotePort is set.
1942 Perl 5.6.0 could emit spurious warnings about redefinition of dl_error()
1943 when statically building extensions into perl. This has been corrected.
1947 L<dprofpp> -R didn't work.
1951 C<*foo{FORMAT}> now works.
1955 Infinity is now recognized as a number.
1959 UNIVERSAL::isa no longer caches methods incorrectly. (This broke
1960 the Tk extension with 5.6.0.)
1964 Lexicals I: lexicals outside an eval "" weren't resolved
1965 correctly inside a subroutine definition inside the eval "" if they
1966 were not already referenced in the top level of the eval""ed code.
1970 Lexicals II: lexicals leaked at file scope into subroutines that
1971 were declared before the lexicals.
1975 Lexical warnings now propagating correctly between scopes
1976 and into C<eval "...">.
1980 C<use warnings qw(FATAL all)> did not work as intended. This has been
1985 warnings::enabled() now reports the state of $^W correctly if the caller
1986 isn't using lexical warnings.
1990 Line renumbering with eval and C<#line> now works.
1994 Fixed numerous memory leaks, especially in eval "".
1998 Localised tied variables no more leak memory
2001 tie my %tied_hash => 'Tie::StdHash';
2005 # Used to leak memory every time local() was called,
2006 # in a loop this added up.
2007 local($tied_hash{Foo}) = 1;
2011 Localised hash elements (and %ENV) are correctly unlocalised to not to
2012 exist, if that's what they were.
2016 tie my %tied_hash => 'Tie::StdHash';
2020 # Nothing has set the FOO element so far
2022 { local $tied_hash{FOO} = 'Bar' }
2024 # This used to print, but not now.
2025 print "exists!\n" if exists $tied_hash{FOO};
2027 As a side effect of this fix, tied hash interfaces B<must> define
2028 the EXISTS and DELETE methods.
2032 mkdir() now ignores trailing slashes in the directory name,
2033 as mandated by POSIX.
2037 Some versions of glibc have a broken modfl(). This affects builds
2038 with C<-Duselongdouble>. This version of Perl detects this brokenness
2039 and has a workaround for it. The glibc release 2.2.2 is known to have
2040 fixed the modfl() bug.
2044 Modulus of unsigned numbers now works (4063328477 % 65535 used to
2045 return 27406, instead of 27047).
2049 Some "not a number" warnings introduced in 5.6.0 eliminated to be
2050 more compatible with 5.005. Infinity is now recognised as a number.
2054 Numeric conversions did not recognize changes in the string value
2055 properly in certain circumstances.
2059 Attributes (like :shared) didn't work with our().
2063 our() variables will not cause "will not stay shared" warnings.
2067 "our" variables of the same name declared in two sibling blocks
2068 resulted in bogus warnings about "redeclaration" of the variables.
2069 The problem has been corrected.
2073 pack "Z" now correctly terminates the string with "\0".
2077 Fix password routines which in some shadow password platforms
2078 (e.g. HP-UX) caused getpwent() to return every other entry.
2082 The PERL5OPT environment variable (for passing command line arguments
2083 to Perl) didn't work for more than a single group of options.
2087 PERL5OPT with embedded spaces didn't work.
2091 printf() no longer resets the numeric locale to "C".
2095 C<qw(a\\b)> now parses correctly as C<'a\\b'>.
2099 pos() did not return the correct value within s///ge in earlier
2100 versions. This is now handled correctly.
2104 Printing quads (64-bit integers) with printf/sprintf now works
2105 without the q L ll prefixes (assuming you are on a quad-capable platform).
2109 Regular expressions on references and overloaded scalars now work.
2113 Right-hand side magic (GMAGIC) could in many cases such as string
2114 concatenation be invoked too many times.
2118 scalar() now forces scalar context even when used in void context.
2122 SOCKS support is now much more robust.
2126 sort() arguments are now compiled in the right wantarray context
2127 (they were accidentally using the context of the sort() itself).
2128 The comparison block is now run in scalar context, and the arguments
2129 to be sorted are always provided list context.
2133 Changed the POSIX character class C<[[:space:]]> to include the (very
2134 rarely used) vertical tab character. Added a new POSIX-ish character
2135 class C<[[:blank:]]> which stands for horizontal whitespace
2136 (currently, the space and the tab).
2140 The tainting behaviour of sprintf() has been rationalized. It does
2141 not taint the result of floating point formats anymore, making the
2142 behaviour consistent with that of string interpolation.
2146 Some cases of inconsistent taint propagation (such as within hash
2147 values) have been fixed.
2151 The RE engine found in Perl 5.6.0 accidentally pessimised certain kinds
2152 of simple pattern matches. These are now handled better.
2156 Regular expression debug output (whether through C<use re 'debug'>
2157 or via C<-Dr>) now looks better.
2161 Multi-line matches like C<"a\nxb\n" =~ /(?!\A)x/m> were flawed. The
2166 Use of $& could trigger a core dump under some situations. This
2171 The regular expression captured submatches ($1, $2, ...) are now
2172 more consistently unset if the match fails, instead of leaving false
2173 data lying around in them.
2177 readline() on files opened in "slurp" mode could return an extra "" at
2178 the end in certain situations. This has been corrected.
2182 Autovivification of symbolic references of special variables described
2183 in L<perlvar> (as in C<${$num}>) was accidentally disabled. This works
2188 Sys::Syslog ignored the C<LOG_AUTH> constant.
2192 All but the first argument of the IO syswrite() method are now optional.
2196 $AUTOLOAD, sort(), lock(), and spawning subprocesses
2197 in multiple threads simultaneously are now thread-safe.
2201 Tie::ARRAY SPLICE method was broken.
2205 Allow read-only string on left hand side of non-modifying tr///.
2209 If C<STDERR> is tied, warnings caused by C<warn> and C<die> now
2210 correctly pass to it.
2214 Several Unicode fixes.
2220 BOMs (byte order marks) in the beginning of Perl files
2221 (scripts, modules) should now be transparently skipped.
2222 UTF-16 (UCS-2) encoded Perl files should now be read correctly.
2226 The character tables have been updated to Unicode 3.2.0.
2230 Comparing with utf8 data does not magically upgrade non-utf8 data
2231 into utf8. (This was a problem for example if you were mixing data
2232 from I/O and Unicode data: your output might have got magically encoded
2237 Generating illegal Unicode code points like U+FFFE, or the UTF-16
2238 surrogates, now also generates an optional warning.
2242 C<IsAlnum>, C<IsAlpha>, and C<IsWord> now match titlecase.
2246 Concatenation with the C<.> operator or via variable interpolation,
2247 C<eq>, C<substr>, C<reverse>, C<quotemeta>, the C<x> operator,
2248 substitution with C<s///>, single-quoted UTF8, should now work.
2252 The C<tr///> operator now works. Note that the C<tr///CU>
2253 functionality has been removed (but see pack('U0', ...)).
2257 C<eval "v200"> now works.
2261 Perl 5.6.0 parsed m/\x{ab}/ incorrectly, leading to spurious warnings.
2262 This has been corrected.
2266 Zero entries were missing from the Unicode classes like C<IsDigit>.
2272 Large unsigned numbers (those above 2**31) could sometimes lose their
2273 unsignedness, causing bogus results in arithmetic operations.
2277 =head2 Platform Specific Changes and Fixes
2285 Perl now works on post-4.0 BSD/OSes.
2291 Setting C<$0> now works (as much as possible; see L<perlvar> for details).
2297 Numerous updates; currently synchronised with Cygwin 1.3.10.
2301 Previously DYNIX/ptx had problems in its Configure probe for non-blocking I/O.
2307 EPOC update after Perl 5.6.0. See README.epoc.
2313 Perl now works on post-3.0 FreeBSDs.
2319 README.hpux updated; C<Configure -Duse64bitall> now works;
2320 now uses HP-UX malloc instead of Perl malloc.
2326 Numerous compilation flag and hint enhancements; accidental mixing
2327 of 32-bit and 64-bit libraries (a doomed attempt) made much harder.
2337 Long doubles should now work (see INSTALL).
2341 Linux previously had problems related to sockaddrlen when using
2342 accept(), revcfrom() (in Perl: recv()), getpeername(), and getsockname().
2350 Compilation of the standard Perl distribution in MacOS Classic should
2351 now work if you have the Metrowerks development environment and
2352 the missing Mac-specific toolkit bits. Contact the macperl mailing
2359 MPE/iX update after Perl 5.6.0. See README.mpeix.
2363 NetBSD/threads: try installing the GNU pth (should be in the
2364 packages collection, or http://www.gnu.org/software/pth/),
2365 and Configure with -Duseithreads.
2371 Perl now works on NetBSD/sparc.
2377 Now works with usethreads (see INSTALL).
2383 64-bitness using the Sun Workshop compiler now works.
2389 The native build method requires at least VOS Release 14.5.0
2390 and GNU C++/GNU Tools 2.0.1 or later. The Perl pack function
2391 now maps overflowed values to +infinity and underflowed values
2396 Tru64 (aka Digital UNIX, aka DEC OSF/1)
2398 The operating system version letter now recorded in $Config{osvers}.
2399 Allow compiling with gcc (previously explicitly forbidden). Compiling
2400 with gcc still not recommended because buggy code results, even with
2407 Fixed various alignment problems that lead into core dumps either
2408 during build or later; no longer dies on math errors at runtime;
2409 now using full quad integers (64 bits), previously was using
2410 only 46 bit integers for speed.
2416 chdir() now works better despite a CRT bug; now works with MULTIPLICITY
2417 (see INSTALL); now works with Perl's malloc.
2419 The tainting of C<%ENV> elements via C<keys> or C<values> was previously
2420 unimplemented. It now works as documented.
2422 The C<waitpid> emulation has been improved. The worst bug (now fixed)
2423 was that a pid of -1 would cause a wildcard search of all processes on
2426 POSIX-style signals are now emulated much better on VMS versions prior
2429 The C<system> function and backticks operator have improved
2430 functionality and better error handling.
2432 File access tests now use current process privileges rather than the
2433 user's default privileges, which could sometimes result in a mismatch
2434 between reported access and actual access.
2436 There is a new C<kill> implementation based on C<sys$sigprc> that allows
2437 older VMS systems (pre-7.0) to use C<kill> to send signals rather than
2438 simply force exit. This implementation also allows later systems to
2439 call C<kill> from within a signal handler.
2441 Iterative logical name translations are now limited to 10 iterations in
2442 imitation of SHOW LOGICAL and other OpenVMS facilities.
2452 accept() no longer leaks memory.
2456 Borland C++ v5.5 is now a supported compiler that can build Perl.
2457 However, the generated binaries continue to be incompatible with those
2458 generated by the other supported compilers (GCC and Visual C++).
2462 Better chdir() return value for a non-existent directory.
2466 Duping socket handles with open(F, ">&MYSOCK") now works under Windows 9x.
2470 New %ENV entries now propagate to subprocesses.
2474 Current directory entries in %ENV are now correctly propagated to child
2479 $ENV{LIB} now used to search for libs under Visual C.
2483 fork() emulation has been improved in various ways, but still continues
2484 to be experimental. See L<perlfork> for known bugs and caveats.
2488 A failed (pseudo)fork now returns undef and sets errno to EAGAIN.
2492 Win32::GetCwd() correctly returns C:\ instead of C: when at the drive root.
2493 Other bugs in chdir() and Cwd::cwd() have also been fixed.
2497 HTML files will be installed in c:\perl\html instead of c:\perl\lib\pod\html
2501 The makefiles now provide a single switch to bulk-enable all the features
2502 enabled in ActiveState ActivePerl (a popular Win32 binary distribution).
2506 Allow REG_EXPAND_SZ keys in the registry.
2510 Can now send() from all threads, not just the first one.
2514 Fake signal handling reenabled, bugs and all.
2518 %SIG has been enabled under USE_ITHREADS, but its use is completely
2519 unsupported under all configurations.
2523 Less stack reserved per thread so that more threads can run
2524 concurrently. (Still 16M per thread.)
2528 C<< File::Spec->tmpdir() >> now prefers C:/temp over /tmp
2529 (works better when perl is running as service).
2533 Better UNC path handling under ithreads.
2537 wait(), waitpid() and backticks now return the correct exit status under
2542 Win64 compilation is now supported.
2546 winsock handle leak fixed.
2550 The Perl parser has been stress tested using both random input and
2551 Markov chain input and the few found crashes and lockups have been
2558 =head1 New or Changed Diagnostics
2564 The lexical warnings category "deprecated" is no longer a sub-category
2565 of the "syntax" category. It is now a top-level category in its own
2570 All regular expression compilation error messages are now hopefully
2571 easier to understand both because the error message now comes before
2572 the failed regex and because the point of failure is now clearly
2573 marked by a C<E<lt>-- HERE> marker.
2577 The various "opened only for", "on closed", "never opened" warnings
2578 drop the C<main::> prefix for filehandles in the C<main> package,
2579 for example C<STDIN> instead of C<main::STDIN>.
2583 The "Unrecognized escape" warning has been extended to include C<\8>,
2584 C<\9>, and C<\_>. There is no need to escape any of the C<\w> characters.
2588 Two new debugging options have been added: if you have compiled your
2589 Perl with debugging, you can use the -DT and -DR options to trace
2590 tokenising and to add reference counts to displaying variables,
2595 The debugger (perl5db.pl) has been modified to present a more
2596 consistent commands interface, via (CommandSet=580). perl5db.t was
2597 also added to test the changes, and as a placeholder for further tests.
2603 The debugger has a new C<dumpDepth> option to control the maximum
2604 depth to which nested structures are dumped. The C<x> command has
2605 been extended so that C<x N EXPR> dumps out the value of I<EXPR> to a
2606 depth of at most I<N> levels.
2610 The debugger can now show lexical variables if you have the CPAN
2611 module PadWalker installed.
2615 If an attempt to use a (non-blessed) reference as an array index
2616 is made, a warning is given.
2620 C<push @a;> and C<unshift @a;> (with no values to push or unshift)
2621 now give a warning. This may be a problem for generated and evaled
2626 If you try to L<perlfunc/pack> a number less than 0 or larger than 255
2627 using the C<"C"> format you will get an optional warning. Similarly
2628 for the C<"c"> format and a number less than -128 or more than 127.
2632 Certain regex modifiers such as C<(?o)> make sense only if applied to
2633 the entire regex. You will get an optional warning if you try to do
2638 Using arrays or hashes as references (e.g. C<< %foo->{bar} >>
2639 has been deprecated for a while. Now you will get an optional warning.
2643 Using C<sort> in scalar context now issues an optional warning.
2644 This didn't do anything useful, as the sort was not performed.
2648 =head1 Changed Internals
2654 perlapi.pod (a companion to perlguts) now attempts to document the
2659 You can now build a really minimal perl called microperl.
2660 Building microperl does not require even running Configure;
2661 C<make -f Makefile.micro> should be enough. Beware: microperl makes
2662 many assumptions, some of which may be too bold; the resulting
2663 executable may crash or otherwise misbehave in wondrous ways.
2664 For careful hackers only.
2668 Added rsignal(), whichsig(), do_join(), op_clear, op_null,
2669 ptr_table_clear(), ptr_table_free(), sv_setref_uv(), and several UTF-8
2670 interfaces to the publicised API. For the full list of the available
2671 APIs see L<perlapi>.
2675 Made possible to propagate customised exceptions via croak()ing.
2679 Now xsubs can have attributes just like subs. (Well, at least the
2680 built-in attributes.)
2684 dTHR and djSP have been obsoleted; the former removed (because it's
2685 a no-op) and the latter replaced with dSP.
2689 PERL_OBJECT has been completely removed.
2693 The MAGIC constants (e.g. C<'P'>) have been macrofied
2694 (e.g. C<PERL_MAGIC_TIED>) for better source code readability
2695 and maintainability.
2699 The regex compiler now maintains a structure that identifies nodes in
2700 the compiled bytecode with the corresponding syntactic features of the
2701 original regex expression. The information is attached to the new
2702 C<offsets> member of the C<struct regexp>. See L<perldebguts> for more
2703 complete information.
2707 The C code has been made much more C<gcc -Wall> clean. Some warning
2708 messages still remain in some platforms, so if you are compiling with
2709 gcc you may see some warnings about dubious practices. The warnings
2710 are being worked on.
2714 F<perly.c>, F<sv.c>, and F<sv.h> have now been extensively commented.
2718 Documentation on how to use the Perl source repository has been added
2719 to F<Porting/repository.pod>.
2723 There are now several profiling make targets.
2727 =head1 Security Vulnerability Closed
2729 (This change was already made in 5.7.0 but bears repeating here.)
2731 A potential security vulnerability in the optional suidperl component
2732 of Perl was identified in August 2000. suidperl is neither built nor
2733 installed by default. As of November 2001 the only known vulnerable
2734 platform is Linux, most likely all Linux distributions. CERT and
2735 various vendors and distributors have been alerted about the vulnerability.
2736 See http://www.cpan.org/src/5.0/sperl-2000-08-05/sperl-2000-08-05.txt
2737 for more information.
2739 The problem was caused by Perl trying to report a suspected security
2740 exploit attempt using an external program, /bin/mail. On Linux
2741 platforms the /bin/mail program had an undocumented feature which
2742 when combined with suidperl gave access to a root shell, resulting in
2743 a serious compromise instead of reporting the exploit attempt. If you
2744 don't have /bin/mail, or if you have 'safe setuid scripts', or if
2745 suidperl is not installed, you are safe.
2747 The exploit attempt reporting feature has been completely removed from
2748 Perl 5.8.0 (and the maintenance release 5.6.1, and it was removed also
2749 from all the Perl 5.7 releases), so that particular vulnerability
2750 isn't there anymore. However, further security vulnerabilities are,
2751 unfortunately, always possible. The suidperl functionality is most
2752 probably going to be removed in Perl 5.10. In any case, suidperl
2753 should only be used by security experts who know exactly what they are
2754 doing and why they are using suidperl instead of some other solution
2755 such as sudo ( see http://www.courtesan.com/sudo/ ).
2759 Several new tests have been added, especially for the F<lib> and F<ext>
2760 subsections. There are now about 65 000 individual tests (spread over
2761 about 700 test scripts), in the regression suite (5.6.1 has about
2762 11700 tests, in 258 test scripts) Many of the new tests are of course
2763 introduced by the new modules, but still in general Perl is now more
2766 Because of the large number of tests, running the regression suite
2767 will take considerably longer time than it used to: expect the suite
2768 to take up to 4-5 times longer to run than in perl 5.6. In a really
2769 fast machine you can hope to finish the suite in about 6-8 minutes
2772 The tests are now reported in a different order than in earlier Perls.
2773 (This happens because the test scripts from under t/lib have been moved
2774 to be closer to the library/extension they are testing.)
2776 =head1 Known Problems
2784 In AIX 4.2 Perl extensions that use C++ functions that use statics
2785 may have problems in that the statics are not getting initialized.
2786 In newer AIX releases this has been solved by linking Perl with
2787 the libC_r library, but unfortunately in AIX 4.2 the said library
2788 has an obscure bug where the various functions related to time
2789 (such as time() and gettimeofday()) return broken values, and
2790 therefore in AIX 4.2 Perl is not linked against the libC_r.
2794 vac 5.0.0.0 May Produce Buggy Code For Perl
2796 The AIX C compiler vac version 5.0.0.0 may produce buggy code,
2797 resulting in few random tests failing, but when the failing tests
2798 are run by hand, they succeed. We suggest upgrading to at least
2799 vac version 5.0.1.0, that has been known to compile Perl correctly.
2800 "lslpp -L|grep vac.C" will tell you the vac version. See README.aix.
2804 If building threaded Perl, you may get compilation warning from pp_sys.c:
2806 "pp_sys.c", line 4651.39: 1506-280 (W) Function argument assignment between types "unsigned char*" and "const void*" is not allowed.
2808 This is harmless; it is caused by the getnetbyaddr() and getnetbyaddr_r()
2809 having slightly different types for their first argument.
2813 =head2 Alpha systems with old gccs fail several tests
2815 If you see op/pack, op/pat, op/regexp, or ext/Storable tests failing
2816 in a Linux/alpha or *BSD/Alpha, it's probably time to upgrade your gcc.
2817 gccs prior to 2.95.3 are definitely not good enough, and gcc 3.1 may
2818 be even better. (RedHat Linux/alpha with gcc 3.1 reported no problems,
2819 as did Linux 2.4.18 with gcc 2.95.4.) (In Tru64, it is preferable to
2820 use the bundled C compiler.)
2824 Perl 5.8.0 doesn't build in AmigaOS. It broke at some point
2825 during the ithreads work and we could not find Amiga experts
2826 to unbreak the problems.
2830 The following tests fail on 5.8.0 Perl in BeOS Personal 5.03:
2832 t/op/lfs............................FAILED at test 17
2833 t/op/magic..........................FAILED at test 24
2834 ext/POSIX/t/sigaction...............FAILED at test 13
2835 ext/POSIX/t/waitpid.................FAILED at test 1
2837 See L<perlbeos> (README.beos) for more details.
2839 =head2 Cygwin "unable to remap"
2841 For example when building the Tk extension for Cygwin,
2842 you may get an error message saying "unable to remap".
2843 This is known problem with Cygwin, and a workaround is
2844 detailed in here: http://sources.redhat.com/ml/cygwin/2001-12/msg00894.html
2846 =head2 ext/threads/t/libc
2848 If this test fails, it indicates that your libc (C library) is not
2849 threadsafe. This particular test stress tests the localtime() call to
2850 find out whether it is threadsafe. See L<perlthrtut> for more information.
2852 =head2 FreeBSD Failing locale Test 117 For ISO8859-15 Locales
2854 The ISO8859-15 locales may fail the locale test 117 in FreeBSD.
2855 This is caused by the characters \xFF (y with diaeresis) and \xBE
2856 (Y with diaeresis) not behaving correctly when being matched
2859 =head2 Modifying $_ Inside for(..)
2863 works without complaint. It shouldn't. (You should be able to
2864 modify only lvalue elements inside the loops.) You can see the
2865 correct behaviour by replacing the 1..5 with 1, 2, 3, 4, 5.
2867 =head2 mod_perl 1.26 Doesn't Build With Threaded Perl
2869 Use mod_perl 1.27 or higher.
2871 =head2 lib/ftmp-security tests warn 'system possibly insecure'
2873 Don't panic. Read INSTALL 'make test' section instead.
2875 =head2 HP-UX lib/posix Subtest 9 Fails When LP64-Configured
2877 If perl is configured with -Duse64bitall, the successful result of the
2878 subtest 10 of lib/posix may arrive before the successful result of the
2879 subtest 9, which confuses the test harness so much that it thinks the
2882 =head2 Linux with glibc 2.2.5 fails t/op/int subtest #6 with -Duse64bitint
2884 This is a known bug in the glibc 2.2.5 with long long integers.
2885 ( http://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=65612 )
2887 =head2 Linux With Sfio Fails op/misc Test 48
2891 =head2 libwww-perl (LWP) fails base/date #51
2893 Use libwww-perl 5.65 or later.
2897 Please remember to set your environment variable LC_ALL to "C"
2898 (setenv LC_ALL C) before running "make test" to avoid a lot of
2899 warnings about the broken locales of Mac OS X.
2901 The following tests are known to fail in Mac OS X 10.1.4 because of
2902 buggy (old) implementations of Berkeley DB included in Mac OS X:
2904 Failed Test Stat Wstat Total Fail Failed List of Failed
2905 -------------------------------------------------------------------------
2906 ../ext/DB_File/t/db-btree.t 0 11 ?? ?? % ??
2907 ../ext/DB_File/t/db-recno.t 149 3 2.01% 61 63 65
2909 If you are building on a UFS partition, you will also probably see
2910 t/op/stat.t subtest #9 fail. This is caused by Darwin's UFS not
2911 supporting inode change time.
2913 Also the ext/POSIX/t/posix.t subtest #10 fails but it is skipped for
2914 now because the failure is Apple's fault, not Perl's (blocked signals
2917 If you Configure with ithreads, ext/threads/t/libc.t will fail, again
2918 not Perl's fault-- the libc of Mac OS X is not threadsafe (in this
2919 particular test the localtime() call is found to be threadunsafe.)
2921 =head2 op/sprintf tests 91, 129, and 130
2923 The op/sprintf tests 91, 129, and 130 are known to fail on some platforms.
2924 Examples include any platform using sfio, and Compaq/Tandem's NonStop-UX.
2926 The test 91 is known to fail at QNX6 (nto), because C<sprintf '%e',0>
2927 incorrectly produces C<0.000000e+0> instead of C<0.000000e+00>.
2929 For the tests 129 and 130 the failing platforms do not comply with
2930 the ANSI C Standard, line 19ff on page 134 of ANSI X3.159 1989 to
2931 be exact. (They produce something other than "1" and "-1" when
2932 formatting 0.6 and -0.6 using the printf format "%.0f", most often
2933 they produce "0" and "-0".)
2937 In case you are still using Solaris 2.5 (aka SunOS 5.5), you may
2938 experience failures (the test core dumping) in lib/locale.t.
2939 The suggested cure is to upgrade your Solaris.
2943 When Perl is built using the native build process on VOS Release
2944 14.5.0 and GNU C++/GNU Tools 2.0.1, all attempted tests either
2945 pass or result in TODO (ignored) failures.
2947 =head2 Term::ReadKey not working on Win32
2949 Use Term::ReadKey 2.20 or later.
2951 =head2 Failure of Thread (5.005-style) tests
2953 B<Note that support for 5.005-style threading is deprecated,
2954 experimental and practically unsupported. In 5.10 it is expected
2957 The following tests are known to fail due to fundamental problems in
2958 the 5.005 threading implementation. These are not new failures--Perl
2959 5.005_0x has the same bugs, but didn't have these tests.
2961 ../ext/List/Util/t/first.t 255 65280 7 4 57.14% 2 5-7
2962 ../lib/English.t 2 512 54 2 3.70% 2-3
2963 ../lib/Filter/Simple/t/data.t 6 3 50.00% 1-3
2964 ../lib/Filter/Simple/t/filter_only 9 3 33.33% 1-2 5
2965 ../lib/autouse.t 10 1 10.00% 4
2966 op/flip.t 15 1 6.67% 15
2968 These failures are unlikely to get fixed as the 5.005-style threads
2969 are considered fundamentally broken. (Basically what happens is that
2970 competing threads can corrupt shared global state.)
2972 =head2 Timing problems
2974 The following tests may fail intermittently because of timing
2975 problems, for example if the system is heavily loaded.
2978 ext/Time/HiRes/HiRes.t
2980 lib/Memoize/t/expmod_t.t
2981 lib/Memoize/t/speed.t
2983 In case of failure please try running them manually, for example
2985 ./perl -Ilib ext/Time/HiRes/HiRes.t
2989 ../lib/Math/Trig.t 26 1 3.85% 25
2990 ../lib/warnings.t 470 1 0.21% 429
2992 The Trig.t failure is caused by the slighly differing (from IEEE)
2993 floating point implementation of UNICOS. The warnings.t failure is
2994 also related: the test assumes a certain floating point output format,
2995 this assumption fails in UNICOS.
3003 During Configure the test
3005 Guessing which symbols your C compiler and preprocessor define...
3007 will probably fail with error messages like
3009 CC-20 cc: ERROR File = try.c, Line = 3
3010 The identifier "bad" is undefined.
3012 bad switch yylook 79bad switch yylook 79bad switch yylook 79bad switch yylook 79#ifdef A29K
3015 CC-65 cc: ERROR File = try.c, Line = 3
3016 A semicolon is expected at this point.
3018 This is caused by a bug in awk utility of UNICOS/mk. You can ignore
3019 the error, but it does cause a slight problem: you cannot fully
3020 benefit from the h2ph utility (see L<h2ph>) that can be used to
3021 convert C headers to Perl libraries, mainly used to be able to access
3022 from Perl the constants defined using C preprocessor, cpp. Because of
3023 the above error parts of the converted headers will be invisible.
3024 Luckily, these days the need for h2ph is rare.
3028 If building Perl with the interpreter threads (ithreads), the
3029 getgrent(), getgrnam(), and getgrgid() functions cannot return the
3030 list of the group members due to a bug in the multithreaded support of
3031 UNICOS/mk. What this means that in list context the functions will
3032 return only three values, not four.
3038 There are a few known test failures, see L<perluts>.
3042 There should be no reported test failures with a default configuration,
3043 though there are a number of tests marked TODO that point to areas
3044 needing further debugging and/or porting work.
3048 In multi-CPU boxes there are some problems with the I/O buffering:
3049 some output may appear twice.
3051 =head2 XML::Parser not working
3053 Use XML::Parser 2.31 or later.
3055 =head2 z/OS (OS/390)
3057 z/OS has rather many test failures but the situation is actually
3058 better than it was in 5.6.0, it's just that so many new modules and
3059 tests have been added.
3061 Failed Test Stat Wstat Total Fail Failed List of Failed
3062 ---------------------------------------------------------------------------
3063 ../ext/Data/Dumper/t/dumper.t 357 8 2.24% 311 314 325 327
3065 ../ext/IO/lib/IO/t/io_unix.t 5 4 80.00% 2-5
3066 ../ext/Storable/t/downgrade.t 12 3072 169 12 7.10% 14-15 46-47 78-79
3068 ../lib/ExtUtils/t/Constant.t 121 30976 48 48 100.00% 1-48
3069 ../lib/ExtUtils/t/Embed.t 9 9 100.00% 1-9
3070 op/pat.t 910 7 0.77% 665 776 785 832-
3072 op/sprintf.t 224 3 1.34% 98 100 136
3073 op/tr.t 97 5 5.15% 63 71-74
3074 uni/fold.t 780 6 0.77% 61 169 196 661
3077 The dumper.t and downgrade.t are problems in the tests, the io_unix
3078 and sprintf are problems in the USS (UDP sockets and printf formats).
3079 The pat, tr, and fold are genuine Perl problems caused by EBCDIC (and
3080 in the pat and fold cases, combining that with Unicode). The Constant
3081 and Embed are probably problems in the tests (since they test Perl's
3082 ability to build extensions, and that seems to be working reasonably well.)
3084 =head2 Localising Tied Arrays and Hashes Is Broken
3088 doesn't work as one would expect: the old value is restored
3089 incorrectly. This will be changed in a future release, but we don't
3090 know yet which the new semantics will exactly be. In any case the
3091 change will break existing code that relies on the current
3092 (ill-defined) semantics, so just avoid doing this in general.
3094 =head2 Self-tying Problems
3096 Self-tying of arrays and hashes is broken in rather deep and
3097 hard-to-fix ways. As a stop-gap measure to avoid people from getting
3098 frustrated at the mysterious results (core dumps, most often) it is
3099 for now forbidden (you will get a fatal error even from an attempt).
3101 A change to self-tying of globs has caused them to be recursively
3102 referenced (see: L<perlobj/"Two-Phased Garbage Collection">). You
3103 will now need an explicit untie to destroy a self-tied glob. This
3104 behaviour may be fixed at a later date.
3106 Self-tying of scalars and IO thingies works.
3108 =head2 Building Extensions Can Fail Because Of Largefiles
3110 Some extensions like mod_perl are known to have issues with
3111 `largefiles', a change brought by Perl 5.6.0 in which file offsets
3112 default to 64 bits wide, where supported. Modules may fail to compile
3113 at all or compile and work incorrectly. Currently there is no good
3114 solution for the problem, but Configure now provides appropriate
3115 non-largefile ccflags, ldflags, libswanted, and libs in the %Config
3116 hash (e.g., $Config{ccflags_nolargefiles}) so the extensions that are
3117 having problems can try configuring themselves without the
3118 largefileness. This is admittedly not a clean solution, and the
3119 solution may not even work at all. One potential failure is whether
3120 one can (or, if one can, whether it's a good idea) link together at
3121 all binaries with different ideas about file offsets, all this is
3124 =head2 Unicode Support on EBCDIC Still Spotty
3126 Though mostly working, Unicode support still has problem spots on
3127 EBCDIC platforms. One such known spot are the C<\p{}> and C<\P{}>
3128 regular expression constructs for code points less than 256: the
3129 C<pP> are testing for Unicode code points, not knowing about EBCDIC.
3131 =head2 The Compiler Suite Is Still Very Experimental
3133 The compiler suite is slowly getting better but it continues to be
3134 highly experimental. Use in production environments is discouraged.
3136 =head2 The Long Double Support Is Still Experimental
3138 The ability to configure Perl's numbers to use "long doubles",
3139 floating point numbers of hopefully better accuracy, is still
3140 experimental. The implementations of long doubles are not yet
3141 widespread and the existing implementations are not quite mature
3142 or standardised, therefore trying to support them is a rare
3143 and moving target. The gain of more precision may also be offset
3144 by slowdown in computations (more bits to move around, and the
3145 operations are more likely to be executed by less optimised
3148 =head2 Seen In Perl 5.7 But Gone Now
3150 C<Time::Piece> (previously known as C<Time::Object>) was removed
3151 because it was felt that it didn't have enough value in it to be a
3152 core module. It is still a useful module, though, and is available
3155 Perl 5.8 unfortunately does not build anymore on AmigaOS,
3156 this broke at some point accidentally. Since there are not that many
3157 Amiga developers available, we could not get this fixed and tested in
3160 =head1 Reporting Bugs
3162 If you find what you think is a bug, you might check the articles
3163 recently posted to the comp.lang.perl.misc newsgroup and the perl
3164 bug database at http://bugs.perl.org/ There may also be
3165 information at http://www.perl.com/ , the Perl Home Page.
3167 If you believe you have an unreported bug, please run the B<perlbug>
3168 program included with your release. Be sure to trim your bug down
3169 to a tiny but sufficient test case. Your bug report, along with the
3170 output of C<perl -V>, will be sent off to perlbug@perl.org to be
3171 analysed by the Perl porting team.
3175 The F<Changes> file for exhaustive details on what changed.
3177 The F<INSTALL> file for how to build Perl.
3179 The F<README> file for general stuff.
3181 The F<Artistic> and F<Copying> files for copyright information.
3185 Written by Jarkko Hietaniemi <F<jhi@iki.fi>>.