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).
660 B<B::Concise> is a new compiler backend for walking the Perl syntax
661 tree, printing concise info about ops, from Stephen McCamant. The
662 output is highly customisable. See L<B::Concise>.
666 The new bignum, bigint, and bigrat pragmas implement transparent
667 bignum support (using the Math::BigInt, Math::BigFloat, and
668 Math::BigRat backends), by Tels.
672 C<Class::ISA> for reporting the search path for a class's ISA tree,
673 by Sean Burke, has been added. See L<Class::ISA>.
677 C<Cwd> has now a split personality: if possible, an XS extension is
678 used, (this will hopefully be faster, more secure, and more robust)
679 but if not possible, the familiar Perl implementation is used.
683 C<Devel::PPPort>, originally from Kenneth Albanowski and now
684 maintained by Paul Marquess, has been added. It is primarily used
685 by C<h2xs> to enhance portability of XS modules between different
690 C<Digest>, frontend module for calculating digests (checksums), from
691 Gisle Aas, has been added. See L<Digest>.
695 C<Digest::MD5> for calculating MD5 digests (checksums) as defined in
696 RFC 1321, from Gisle Aas, has been added. See L<Digest::MD5>.
698 use Digest::MD5 'md5_hex';
700 $digest = md5_hex("Thirsty Camel");
702 print $digest, "\n"; # 01d19d9d2045e005c3f1b80e8b164de1
704 NOTE: the C<MD5> backward compatibility module is deliberately not
705 included since its further use is discouraged.
709 C<Encode>, orginally by Nick Ing-Simmons and now maintained by Dan
710 Kogai, provides a mechanism to translate between different character
711 encodings. Support for Unicode, ISO-8859-1, and ASCII are compiled in
712 to the module. Several other encodings (like the rest of the
713 ISO-8859, CP*/Win*, Mac, KOI8-R, three variants EBCDIC, Chinese,
714 Japanese, and Korean encodings) are included and can be loaded at
715 runtime. (For space considerations, the largest Chinese encodings
716 have been separated into their own CPAN module, Encode::HanExtra,
717 which Encode will use if available). See L<Encode>.
719 Any encoding supported by Encode module is also available to the
720 ":encoding()" layer if PerlIO is used.
724 C<Hash::Util> is the interface to the new I<restricted hashes>
725 feature. (Implemented by Jeffrey Friedl, Nick Ing-Simmons, and
730 C<I18N::Langinfo> can be use to query locale information.
731 See L<I18N::Langinfo>.
735 C<I18N::LangTags> has functions for dealing with RFC3066-style
736 language tags, by Sean Burke. See L<I18N::LangTags>.
740 C<ExtUtils::Constant> is a new tool for extension writers for
741 generating XS code to import C header constants, by Nicholas Clark.
742 See L<ExtUtils::Constant>.
746 C<Filter::Simple> is an easy-to-use frontend to Filter::Util::Call,
747 from Damian Conway. See L<Filter::Simple>.
753 use Filter::Simple sub {
754 while (my ($from, $to) = splice @_, 0, 2) {
763 use MyFilter qr/red/ => 'green';
765 print "red\n"; # this code is filtered, will print "green\n"
766 print "bored\n"; # this code is filtered, will print "bogreen\n"
770 print "red\n"; # this code is not filtered, will print "red\n"
774 C<File::Temp> allows one to create temporary files and directories in
775 an easy, portable, and secure way, by Tim Jenness. See L<File::Temp>.
779 C<Filter::Util::Call> provides you with the framework to write
780 I<Source Filters> in Perl, from Paul Marquess. For most uses the
781 frontend Filter::Simple is to be preferred. See L<Filter::Util::Call>.
785 C<if> is a new pragma for conditional inclusion of modules, from
790 L<libnet> is a collection of perl5 modules related to network
791 programming, from Graham Barr. See L<Net::FTP>, L<Net::NNTP>,
792 L<Net::Ping> (not part of libnet, but related), L<Net::POP3>,
793 L<Net::SMTP>, and L<Net::Time>.
795 Perl installation leaves libnet unconfigured, use F<libnetcfg> to configure.
799 C<List::Util> is a selection of general-utility list subroutines, like
800 sum(), min(), first(), and shuffle(), by Graham Barr. See L<List::Util>.
804 C<Locale::Constants>, C<Locale::Country>, C<Locale::Currency>
805 C<Locale::Language>, and L<Locale::Script>, from Neil Bowers, have
806 been added. They provide the codes for various locale standards, such
807 as "fr" for France, "usd" for US Dollar, and "ja" for Japanese.
811 $country = code2country('jp'); # $country gets 'Japan'
812 $code = country2code('Norway'); # $code gets 'no'
814 See L<Locale::Constants>, L<Locale::Country>, L<Locale::Currency>,
815 and L<Locale::Language>.
819 C<Locale::Maketext> is localization framework from Sean Burke. See
820 L<Locale::Maketext>, and L<Locale::Maketext::TPJ13>. The latter is an
821 article about software localization, originally published in The Perl
822 Journal #13, republished here with kind permission.
826 C<Math::BigRat> for big rational numbers, to accompany Math::BigInt and
827 Math::BigFloat, from Tels.
831 C<Memoize> can make your functions faster by trading space for time,
832 from Mark-Jason Dominus. See L<Memoize>.
836 C<MIME::Base64> allows you to encode data in base64, from Gisle Aas,
837 as defined in RFC 2045 - I<MIME (Multipurpose Internet Mail
842 $encoded = encode_base64('Aladdin:open sesame');
843 $decoded = decode_base64($encoded);
845 print $encoded, "\n"; # "QWxhZGRpbjpvcGVuIHNlc2FtZQ=="
851 C<MIME::QuotedPrint> allows you to encode data in quoted-printable
852 encoding, as defined in RFC 2045 - I<MIME (Multipurpose Internet Mail
853 Extensions)>, from Gisle Aas.
855 use MIME::QuotedPrint;
857 $encoded = encode_qp("Smiley in Unicode: \x{263a}");
858 $decoded = decode_qp($encoded);
860 print $encoded, "\n"; # "Smiley in Unicode: =263A"
862 MIME::QuotedPrint has been enhanced to provide the basic methods
863 necessary to use it with PerlIO::Via as in :
865 use MIME::QuotedPrint;
866 open($fh,">Via(MIME::QuotedPrint)",$path);
868 See L<MIME::QuotedPrint>.
872 C<NEXT> is pseudo-class for method redispatch, from Damian Conway.
877 C<open> is a new pragma for setting the default I/O disciplines
882 C<PerlIO::Scalar> provides the implementation of IO to "in memory"
883 Perl scalars as discussed above, from Nick Ing-Simmons. It also
884 serves as an example of a loadable PerlIO layer. Other future
885 possibilities include PerlIO::Array and PerlIO::Code.
886 See L<PerlIO::Scalar>.
890 C<PerlIO::Via> acts as a PerlIO layer and wraps PerlIO layer
891 functionality provided by a class (typically implemented in perl
892 code), from Nick Ing-Simmons.
894 use MIME::QuotedPrint;
895 open($fh,">Via(MIME::QuotedPrint)",$path);
897 This will automatically convert everything output to C<$fh>
898 to Quoted-Printable. See L<PerlIO::Via>.
902 C<Pod::ParseLink>, by Russ Allbery, has been added,
903 to parse LZ<><> links in pods as described in the new
908 C<Pod::Text::Overstrike>, by Joe Smith, has been added.
909 It converts POD data to formatted overstrike text.
910 See L<Pod::Text::Overstrike>.
914 C<Scalar::Util> is a selection of general-utility scalar subroutines,
915 like blessed(), reftype(), and tainted(). See L<Scalar::Util>.
919 C<sort> is a new pragma for controlling the behaviour of sort().
923 C<Storable> gives persistence to Perl data structures by allowing the
924 storage and retrieval of Perl data to and from files in a fast and
925 compact binary format. Because in effect Storable does serialisation
926 of Perl data structues, with it you can also clone deep, hierarchical
927 datastructures. Storable was originally created by Raphael Manfredi,
928 but it is now maintained by Abhijit Menon-Sen. Storable has been
929 enhanced to understand the two new hash features, Unicode keys and
930 restricted hashes. See L<Storable>.
934 C<Switch>, from Damian Conway, has been added. Just by saying
938 you have C<switch> and C<case> available in Perl.
944 case 1 { print "number 1" }
945 case "a" { print "string a" }
946 case [1..10,42] { print "number in list" }
947 case (@array) { print "number in list" }
948 case /\w+/ { print "pattern" }
949 case qr/\w+/ { print "pattern" }
950 case (%hash) { print "entry in hash" }
951 case (\%hash) { print "entry in hash" }
952 case (\&sub) { print "arg to subroutine" }
953 else { print "previous case not true" }
960 C<Test::More> is yet another framework for writing test scripts,
961 more extensive than Test::Simple, by Michael Schwern. See L<Test::More>.
965 C<Test::Simple> has basic utilities for writing tests, by Michael
966 Schwern. See L<Test::Simple>.
970 C<Text::Balanced> has been added, for extracting delimited text
971 sequences from strings, from Damian Conway.
973 use Text::Balanced 'extract_delimited';
975 ($a, $b) = extract_delimited("'never say never', he never said", "'", '');
977 $a will be "'never say never'", $b will be ', he never said'.
979 In addition to extract_delimited() there are also extract_bracketed(),
980 extract_quotelike(), extract_codeblock(), extract_variable(),
981 extract_tagged(), extract_multiple(), gen_delimited_pat(), and
982 gen_extract_tagged(). With these you can implement rather advanced
983 parsing algorithms. See L<Text::Balanced>.
987 C<threads> is an interface to interpreter threads, by Arthur Bergman.
988 Interpreter threads (ithreads) is the new thread model introduced in
989 Perl 5.6 but only available as an internal interface for extension
990 writers (and for Win32 Perl for C<fork()> emulation). See L<threads>.
994 C<threads::shared> allows data sharing for interpreter threads, from
995 Arthur Bergman. In the ithreads model any data sharing between
996 threads must be explicit, as opposed to the old 5.005 thread model
997 where data sharing was implicit. See L<threads::shared>.
1001 C<Tie::File>, by Mark-Jason Dominus, associates a Perl array with the
1006 C<Tie::Memoize>, by Ilya Zakharevich, provides on-demand loaded hashes.
1010 C<Tie::RefHash::Nestable>, by Edward Avis, allows storing hash
1011 references (unlike the standard Tie::RefHash) The module is contained
1012 within Tie::RefHash, see L<Tie::RefHash>.
1016 C<Time::HiRes> provides high resolution timing (ualarm, usleep,
1017 and gettimeofday), from Douglas E. Wegscheid. See L<Time::HiRes>.
1021 C<Unicode::UCD> offers a querying interface to the Unicode Character
1022 Database. See L<Unicode::UCD>.
1026 C<Unicode::Collate> implements the UCA (Unicode Collation Algorithm)
1027 for sorting Unicode strings, by SADAHIRO Tomoyuki. See L<Unicode::Collate>.
1031 C<Unicode::Normalize> implements the various Unicode normalization
1032 forms, by SADAHIRO Tomoyuki. See L<Unicode::Normalize>.
1036 C<XS::Typemap>, by Tim Jenness, is a test extension that exercises XS
1037 typemaps. Nothing gets installed but for extension writers the code
1042 =head2 Updated And Improved Modules and Pragmata
1048 The following independently supported modules have been updated to the
1049 newest versions from CPAN: CGI, CPAN, DB_File, File::Spec, File::Temp,
1050 Getopt::Long, Math::BigFloat, Math::BigInt, the podlators bundle
1051 (Pod::Man, Pod::Text), Pod::LaTeX, Pod::Parser, Storable,
1052 Term::ANSIColor, Test, Text-Tabs+Wrap.
1056 The attributes::reftype() now works on tied arguments.
1060 AutoLoader can now be disabled with C<no AutoLoader;>.
1064 B::Deparse has been significantly enhanced. It now can deparse almost
1065 all of the standard test suite (so that the tests still succeed).
1066 There is a make target "test.deparse" for trying this out.
1070 Class::Struct can now define the classes in compile time.
1074 Class::Struct now assigns the array/hash element if the accessor
1075 is called with an array/hash element as the B<sole> argument.
1079 The return value of Cwd::fastcwd() is now tainted.
1083 Data::Dumper has now an option to sort hashes.
1087 Data::Dumper has now an option to dump code references
1092 DB_File now supports newer Berkeley DB versions, among
1097 Devel::Peek now has an interface for the Perl memory statistics
1098 (this works only if you are using perl's malloc, and if you have
1099 compiled with debugging).
1103 The English module can now be used without the infamous performance
1106 use English '-no_match_vars';
1108 (Assuming, of course, that one doesn't need the troublesome variables
1109 C<$`>, C<$&>, or C<$'>.) Also, introduced C<@LAST_MATCH_START> and
1110 C<@LAST_MATCH_END> English aliases for C<@-> and C<@+>.
1114 ExtUtils::MakeMaker now uses File::Spec internally, which hopefully
1115 leads into better portability.
1119 Fcntl, Socket, and Sys::Syslog have been rewritten to use the
1120 new-style constant dispatch section (see L<ExtUtils::Constant>).
1121 This means that they will be more robust and hopefully faster.
1125 File::Find now chdir()s correctly when chasing symbolic links.
1129 File::Find now has pre- and post-processing callbacks. It also
1130 correctly changes directories when chasing symbolic links. Callbacks
1131 (naughtily) exiting with "next;" instead of "return;" now work.
1135 File::Find is now (again) reentrant. It also has been made
1140 The warnings issued by File::Find now belong to their own category.
1141 You can enable/disable them with C<use/no warnings 'File::Find';>.
1145 File::Glob::glob() renamed to File::Glob::bsd_glob() to avoid
1146 prototype mismatch with CORE::glob().
1150 File::Glob now supports C<GLOB_LIMIT> constant to limit the size of
1151 the returned list of filenames.
1155 IPC::Open3 now allows the use of numeric file descriptors.
1159 IO::Socket has now atmark() method, which returns true if the socket
1160 is positioned at the out-of-band mark. The method is also exportable
1161 as a sockatmark() function.
1165 IO::Socket::INET has support for ReusePort option (if your platform
1166 supports it). The Reuse option now has an alias, ReuseAddr. For clarity
1167 you may want to prefer ReuseAddr.
1171 IO::Socket::INET now supports C<LocalPort> of zero (usually meaning
1172 that the operating system will make one up.)
1176 use lib now works identically to @INC. Removing directories
1177 with 'no lib' now works.
1181 Math::BigFloat and Math::BigInt have undergone a full rewrite.
1182 They are now magnitudes faster, and they support various
1183 bignum libraries such as GMP and PARI as their backends.
1187 Math::Complex handles inf, NaN etc., better.
1191 Net::Ping has been muchly enhanced: multihoming is now supported,
1192 Win32 functionality is better, there is now time measuring
1193 functionality (optionally high-resolution using Time::HiRes),
1194 and there is now "external" protocol which uses Net::Ping::External
1195 module which runs your external ping utility and parses the output.
1196 A version of Net::Ping::External is available in CPAN.
1198 Note that some of the Net::Ping tests are disabled when running
1199 under the Perl distribution since one cannot assume one or more
1200 of the following: enabled echo port at localhost, full Internet
1201 connectivity, or sympathetic firewalls. You can set the environment
1202 variable PERL_TEST_Net_Ping to "1" (one) before running the Perl test
1203 suite to enable all the Net::Ping tests.
1207 POSIX::sigaction() is now much more flexible and robust.
1208 You can now install coderef handlers, 'DEFAULT', and 'IGNORE'
1209 handlers, installing new handlers was not atomic.
1213 In Safe the C<%INC> now localised in a Safe compartment so that
1218 In SDBM_File on dosish platforms, some keys went missing because of
1219 lack of support for files with "holes". A workaround for the problem
1224 In Search::Dict one can now have a pre-processing hook for the
1225 lines being searched.
1229 The Shell module now has an OO interface.
1233 In Sys::Syslog there is now a failover mechanism that will go
1234 through alternative connection mechanisms until the message
1235 is successfully logged.
1239 The Test module has been significantly enhanced.
1243 Time::Local::timelocal() does not handle fractional seconds anymore.
1244 The rationale is that neither does localtime(), and timelocal() and
1245 localtime() are supposed to be inverses of each other.
1249 The vars pragma now supports declaring fully qualified variables.
1250 (Something that C<our()> does not and will not support.)
1254 The C<utf8::> name space (as in the pragma) provides various
1255 Perl-callable functions to provide low level access to Perl's
1256 internal Unicode representation. At the moment only length()
1257 has been implemented.
1261 =head1 Utility Changes
1267 Emacs perl mode (emacs/cperl-mode.el) has been updated to version
1272 F<emacs/e2ctags.pl> is now much faster.
1276 C<enc2xs> is a tool for people adding their own encodings to the
1281 C<h2ph> now supports C trigraphs.
1285 C<h2xs> now produces a template README.
1289 C<h2xs> now uses C<Devel::PPort> for better portability between
1290 different versions of Perl.
1294 C<h2xs> uses the new L<ExtUtils::Constant> module which will affect
1295 newly created extensions that define constants. Since the new code is
1296 more correct (if you have two constants where the first one is a
1297 prefix of the second one, the first constant B<never> gets defined),
1298 less lossy (it uses integers for integer constant, as opposed to the
1299 old code that used floating point numbers even for integer constants),
1300 and slightly faster, you might want to consider regenerating your
1301 extension code (the new scheme makes regenerating easy).
1302 L<h2xs> now also supports C trigraphs.
1306 C<libnetcfg> has been added to configure the libnet.
1310 C<perlbug> is now much more robust. It also sends the bug report to
1311 perl.org, not perl.com.
1315 C<perlcc> has been rewritten and its user interface (that is,
1316 command line) is much more like that of the UNIX C compiler, cc.
1317 (The perlbc tools has been removed. Use C<perlcc -B> instead.)
1318 B<Note that perlcc is still considered very experimental and
1323 C<perlivp> is a new Installation Verification Procedure utility
1324 for running any time after installing Perl.
1328 C<piconv> is an implementation of the character conversion utility
1329 C<iconv>, demonstrating the new Encode module.
1333 C<pod2html> now allows specifying a cache directory.
1337 C<pod2html> now produces XHTML 1.0.
1341 C<pod2html> now understands POD written using different line endings
1342 (PC-like CRLF versus UNIX-like LF versus MacClassic-like CR).
1346 C<s2p> has been completely rewritten in Perl. (It is in fact a full
1347 implementation of sed in Perl: you can use the sed functionality by
1348 using the C<psed> utility.)
1352 C<xsubpp> now understands POD documentation embedded in the *.xs files.
1356 C<xsubpp> now supports OUT keyword.
1360 =head1 New Documentation
1366 perl56delta details the changes between the 5.005 release and the
1371 perlclib documents the internal replacements for standard C library
1372 functions. (Interesting only for extension writers and Perl core
1377 perldebtut is a Perl debugging tutorial.
1381 perlebcdic contains considerations for running Perl on EBCDIC platforms.
1385 perlintro is a gentle introduction to Perl.
1389 perliol documents the internals of PerlIO with layers.
1393 perlmodstyle is a style guide for writing modules.
1397 perlnewmod tells about writing and submitting a new module.
1401 perlpacktut is a pack() tutorial.
1405 perlpod has been rewritten to be clearer and to record the best
1406 practices gathered over the years.
1410 perlpodspec is a more formal specification of the pod format,
1411 mainly of interest for writers of pod applications, not to
1412 people writing in pod.
1416 perlretut is a regular expression tutorial.
1420 perlrequick is a regular expressions quick-start guide.
1421 Yes, much quicker than perlretut.
1425 perltodo has been updated.
1429 perltootc has been renamed as perltooc (to not to conflict
1430 with perltoot in filesystems restricted to "8.3" names)
1434 perluniintro is an introduction to using Unicode in Perl.
1435 (perlunicode is more of a detailed reference and background
1440 perlutil explains the command line utilities packaged with the Perl
1445 The following platform-specific documents are available before
1446 the installation as README.I<platform>, and after the installation
1449 perlaix perlamiga perlapollo perlbeos perlbs2000
1450 perlce perlcygwin perldgux perldos perlepoc perlhpux
1451 perlhurd perlmachten perlmacos perlmint perlmpeix
1452 perlnetware perlos2 perlos390 perlplan9 perlqnx perlsolaris
1453 perltru64 perluts perlvmesa perlvms perlvos perlwin32
1459 The documentation for the POSIX-BC platform is called "BS2000", to avoid
1460 confusion with the Perl POSIX module.
1464 The documentation for the WinCE platform is called perlce (README.ce
1465 in the source code kit), to avoid confusion with the perlwin32
1466 documentation on 8.3-restricted filesystems.
1470 =head1 Performance Enhancements
1476 map() could get pathologically slow when the result list it generates
1477 is larger than the source list. The performance has been improved for
1482 sort() has been changed to use primarily mergesort internally as
1483 opposed to the earlier quicksort. For very small lists this may
1484 result in slightly slower sorting times, but in general the speedup
1485 should be at least 20%. Additional bonuses are that the worst case
1486 behaviour of sort() is now better (in computer science terms it now
1487 runs in time O(N log N), as opposed to quicksort's Theta(N**2)
1488 worst-case run time behaviour), and that sort() is now stable
1489 (meaning that elements with identical keys will stay ordered as they
1490 were before the sort). See the C<sort> pragma for information.
1492 The story in more detail: suppose you want to serve yourself a little
1495 @digits = ( 3,1,4,1,5,9 );
1497 A numerical sort of the digits will yield (1,1,3,4,5,9), as expected.
1498 Which C<1> comes first is hard to know, since one C<1> looks pretty
1499 much like any other. You can regard this as totally trivial,
1500 or somewhat profound. However, if you just want to sort the even
1501 digits ahead of the odd ones, then what will
1503 sort { ($a % 2) <=> ($b % 2) } @digits;
1505 yield? The only even digit, C<4>, will come first. But how about
1506 the odd numbers, which all compare equal? With the quicksort algorithm
1507 used to implement Perl 5.6 and earlier, the order of ties is left up
1508 to the sort. So, as you add more and more digits of Pi, the order
1509 in which the sorted even and odd digits appear will change.
1510 and, for sufficiently large slices of Pi, the quicksort algorithm
1511 in Perl 5.8 won't return the same results even if reinvoked with the
1512 same input. The justification for this rests with quicksort's
1513 worst case behavior. If you run
1515 sort { $a <=> $b } ( 1 .. $N , 1 .. $N );
1517 (something you might approximate if you wanted to merge two sorted
1518 arrays using sort), doubling $N doesn't just double the quicksort time,
1519 it I<quadruples> it. Quicksort has a worst case run time that can
1520 grow like N**2, so-called I<quadratic> behaviour, and it can happen
1521 on patterns that may well arise in normal use. You won't notice this
1522 for small arrays, but you I<will> notice it with larger arrays,
1523 and you may not live long enough for the sort to complete on arrays
1524 of a million elements. So the 5.8 quicksort scrambles large arrays
1525 before sorting them, as a statistical defence against quadratic behaviour.
1526 But that means if you sort the same large array twice, ties may be
1527 broken in different ways.
1529 Because of the unpredictability of tie-breaking order, and the quadratic
1530 worst-case behaviour, quicksort was I<almost> replaced completely with
1531 a stable mergesort. I<Stable> means that ties are broken to preserve
1532 the original order of appearance in the input array. So
1534 sort { ($a % 2) <=> ($b % 2) } (3,1,4,1,5,9);
1536 will yield (4,3,1,1,5,9), guaranteed. The even and odd numbers
1537 appear in the output in the same order they appeared in the input.
1538 Mergesort has worst case O(NlogN) behaviour, the best value
1539 attainable. And, ironically, this mergesort does particularly
1540 well where quicksort goes quadratic: mergesort sorts (1..$N, 1..$N)
1541 in O(N) time. But quicksort was rescued at the last moment because
1542 it is faster than mergesort on certain inputs and platforms.
1543 For example, if you really I<don't> care about the order of even
1544 and odd digits, quicksort will run in O(N) time; it's very good
1545 at sorting many repetitions of a small number of distinct elements.
1546 The quicksort divide and conquer strategy works well on platforms
1547 with relatively small, very fast, caches. Eventually, the problem gets
1548 whittled down to one that fits in the cache, from which point it
1549 benefits from the increased memory speed.
1551 Quicksort was rescued by implementing a sort pragma to control aspects
1552 of the sort. The B<stable> subpragma forces stable behaviour,
1553 regardless of algorithm. The B<_quicksort> and B<_mergesort>
1554 subpragmas are heavy-handed ways to select the underlying implementation.
1555 The leading C<_> is a reminder that these subpragmas may not survive
1556 beyond 5.8. More appropriate mechanisms for selecting the implementation
1557 exist, but they wouldn't have arrived in time to save quicksort.
1561 Hashes now use Bob Jenkins "One-at-a-Time" hashing key algorithm
1562 ( http://burtleburtle.net/bob/hash/doobs.html ). This algorithm is
1563 reasonably fast while producing a much better spread of values than
1564 the old hashing algorithm (originally by Chris Torek, later tweaked by
1565 Ilya Zakharevich). Hash values output from the algorithm on a hash of
1566 all 3-char printable ASCII keys comes much closer to passing the
1567 DIEHARD random number generation tests. According to perlbench, this
1568 change has not affected the overall speed of Perl.
1572 unshift() should now be noticeably faster.
1576 =head1 Installation and Configuration Improvements
1578 =head2 Generic Improvements
1584 INSTALL now explains how you can configure Perl to use 64-bit
1585 integers even on non-64-bit platforms.
1589 Policy.sh policy change: if you are reusing a Policy.sh file
1590 (see INSTALL) and you use Configure -Dprefix=/foo/bar and in the old
1591 Policy $prefix eq $siteprefix and $prefix eq $vendorprefix, all of
1592 them will now be changed to the new prefix, /foo/bar. (Previously
1593 only $prefix changed.) If you do not like this new behaviour,
1594 specify prefix, siteprefix, and vendorprefix explicitly.
1598 A new optional location for Perl libraries, otherlibdirs, is available.
1599 It can be used for example for vendor add-ons without disturbing Perl's
1600 own library directories.
1604 In many platforms the vendor-supplied 'cc' is too stripped-down to
1605 build Perl (basically, 'cc' doesn't do ANSI C). If this seems
1606 to be the case and 'cc' does not seem to be the GNU C compiler
1607 'gcc', an automatic attempt is made to find and use 'gcc' instead.
1611 gcc needs to closely track the operating system release to avoid
1612 build problems. If Configure finds that gcc was built for a different
1613 operating system release than is running, it now gives a clearly visible
1614 warning that there may be trouble ahead.
1618 Since Perl 5.8 is not binary-compatible with previous releases
1619 of Perl, Configure no longer suggests including the 5.005
1624 Configure C<-S> can now run non-interactively.
1628 Configure support for pdp11-style memory models has been removed due
1633 configure.gnu now works with options with whitespace in them.
1637 installperl now outputs everything to STDERR.
1641 Because PerlIO is now the default on most platforms, "-perlio" doesn't
1642 get appended to the $Config{archname} (also known as $^O) anymore.
1643 Instead, if you explicitly choose not to use perlio (Configure command
1644 line option -Uuseperlio), you will get "-stdio" appended.
1648 Another change related to the architecture name is that "-64all"
1649 (-Duse64bitall, or "maximally 64-bit") is appended only if your
1650 pointers are 64 bits wide. (To be exact, the use64bitall is ignored.)
1654 In AFS installations one can configure the root of the AFS to be
1655 somewhere else than the default F</afs> by using the Configure
1656 parameter C<-Dafsroot=/some/where/else>.
1660 APPLLIB_EXP, a less-know configuration-time definition, has been
1661 documented. It can be used to prepend site-specific directories
1662 to Perl's default search path (@INC), see INSTALL for information.
1666 The version of Berkeley DB used when the Perl (and, presumably, the
1667 DB_File extension) was built is now available as
1668 C<@Config{qw(db_version_major db_version_minor db_version_patch)}>
1669 from Perl and as C<DB_VERSION_MAJOR_CFG DB_VERSION_MINOR_CFG
1670 DB_VERSION_PATCH_CFG> from C.
1674 Building Berkeley DB3 for compatibility modes for DB, NDBM, and ODBM
1675 has been documented in INSTALL.
1679 If you have CPAN access (either network or a local copy such as a
1680 CD-ROM) you can during specify extra modules to Configure to build and
1681 install with Perl using the -Dextras=... option. See INSTALL for
1686 In addition to config.over a new override file, config.arch, is
1687 available. That is supposed to be used by hints file writers for
1688 architecture-wide changes (as opposed to config.over which is for
1693 If your file system supports symbolic links you can build Perl outside
1694 of the source directory by
1696 mkdir /tmp/perl/build/directory
1697 cd /tmp/perl/build/directory
1698 sh /path/to/perl/source/Configure -Dmksymlinks ...
1700 This will create in /tmp/perl/build/directory a tree of symbolic links
1701 pointing to files in /path/to/perl/source. The original files are left
1702 unaffected. After Configure has finished you can just say
1706 and Perl will be built and tested, all in /tmp/perl/build/directory.
1710 For Perl developers several new make targets for profiling
1711 and debugging have been added, see L<perlhack>.
1717 Use of the F<gprof> tool to profile Perl has been documented in
1718 L<perlhack>. There is a make target called "perl.gprof" for
1719 generating a gprofiled Perl executable.
1723 If you have GCC 3, there is a make target called "perl.gcov" for
1724 creating a gcoved Perl executable for coverage analysis. See
1729 If you are on IRIX or Tru64 platforms, new profiling/debugging options
1730 have been added, see L<perlhack> for more information about pixie and
1737 Guidelines of how to construct minimal Perl installations have
1738 been added to INSTALL.
1742 The Thread extension is now not built at all under ithreads
1743 (C<Configure -Duseithreads>) because it wouldn't work anyway (the
1744 Thread extension requires being Configured with C<-Duse5005threads>).
1746 But note that the Thread.pm interface is now shared by both
1751 The Gconvert macro ($Config{d_Gconvert}) used by perl for stringifying
1752 floating-point numbers is now more picky about using sprintf %.*g
1753 rules for the conversion. Some platforms that used to use gcvt may
1754 now resort to the slower sprintf.
1758 The obsolete method of making a special (e.g., debugging) flavor
1761 make LIBPERL=libperld.a
1763 has been removed. Use -DDEBUGGING instead.
1767 =head2 New Or Improved Platforms
1769 For the list of platforms known to support Perl,
1770 see L<perlport/"Supported Platforms">.
1776 AIX dynamic loading should be now better supported.
1780 AIX should now work better with gcc, threads, and 64-bitness. Also the
1781 long doubles support in AIX should be better now. See L<perlaix>.
1785 AtheOS ( http://www.atheos.cx/ ) is a new platform.
1789 BeOS has been reclaimed.
1793 DG/UX platform now supports the 5.005-style threads. See L<perldgux>.
1797 DYNIX/ptx platform (a.k.a. dynixptx) is supported at or near osvers 4.5.2.
1801 EBCDIC platforms (z/OS, also known as OS/390, POSIX-BC, and VM/ESA)
1802 have been regained. Many test suite tests still fail and the
1803 co-existence of Unicode and EBCDIC isn't quite settled, but the
1804 situation is much better than with Perl 5.6. See L<perlos390>,
1805 L<perlbs2000> (for POSIX-BC), and L<perlvmesa> for more information.
1809 Building perl with -Duseithreads or -Duse5005threads now works under
1810 HP-UX 10.20 (previously it only worked under 10.30 or later). You will
1811 need a thread library package installed. See README.hpux.
1815 MacOS Classic (MacPerl has of course been available since
1816 perl 5.004 but now the source code bases of standard Perl
1817 and MacPerl have been synchronised)
1821 MacOS X (or Darwin) should now be able to build Perl even on HFS+
1822 filesystems. (The case-insensitivity confused the Perl build process.)
1826 NCR MP-RAS is now supported.
1830 All the NetBSD specific patches (except for the installation
1831 specific ones) have been merged back to the main distribution.
1835 NetWare from Novell is now supported. See L<perlnetware>.
1839 NonStop-UX is now supported.
1843 NEC SUPER-UX is now supported.
1847 All the OpenBSD specific patches (except for the installation
1848 specific ones) have been merged back to the main distribution.
1852 Perl has been tested with the GNU pth userlevel thread package
1853 ( http://www.gnu.org/software/pth/pth.html ) . All but one thread
1854 test worked, and that one failure was because of test results arriving
1855 in unexpected order.
1859 Stratus VOS is now supported using Perl's native build method
1860 (Configure). This is the recommended method to build Perl on
1861 VOS. The older methods, which build miniperl, are still
1862 available. See L<perlvos>.
1866 Amdahl UTS UNIX mainframe platform is now supported.
1870 WinCE is now supported. See L<perlce>.
1874 z/OS (formerly known as OS/390, formerly known as MVS OE) has now
1875 support for dynamic loading. This is not selected by default,
1876 however, you must specify -Dusedl in the arguments of Configure.
1880 =head1 Selected Bug Fixes
1882 Numerous memory leaks and uninitialized memory accesses have been
1883 hunted down. Most importantly anonymous subs used to leak quite
1890 The autouse pragma didn't work for Multi::Part::Function::Names.
1894 caller() could cause core dumps in certain situations. Carp was sometimes
1895 affected by this problem. In particular, caller() now returns a
1896 subroutine name of C<(unknown)> for subroutines that have been removed
1897 from the symbol table.
1901 chop(@list) in list context returned the characters chopped in
1902 reverse order. This has been reversed to be in the right order.
1906 Configure no longer includes the DBM libraries (dbm, gdbm, db, ndbm)
1907 when building the Perl binary. The only exception to this is SunOS 4.x,
1912 The behaviour of non-decimal but numeric string constants such as
1913 "0x23" was platform-dependent: in some platforms that was seen as 35,
1914 in some as 0, in some as a floating point number (don't ask). This
1915 was caused by Perl using the operating system libraries in a situation
1916 where the result of the string to number conversion is undefined: now
1917 Perl consistently handles such strings as zero in numeric contexts.
1921 The order of DESTROYs has been made more predictable.
1925 Several debugger fixes: exit code now reflects the script exit code,
1926 condition C<"0"> now treated correctly, the C<d> command now checks
1927 line number, the C<$.> no longer gets corrupted, all debugger output
1928 now goes correctly to the socket if RemotePort is set.
1932 Perl 5.6.0 could emit spurious warnings about redefinition of dl_error()
1933 when statically building extensions into perl. This has been corrected.
1937 L<dprofpp> -R didn't work.
1941 C<*foo{FORMAT}> now works.
1945 Infinity is now recognized as a number.
1949 UNIVERSAL::isa no longer caches methods incorrectly. (This broke
1950 the Tk extension with 5.6.0.)
1954 Lexicals I: lexicals outside an eval "" weren't resolved
1955 correctly inside a subroutine definition inside the eval "" if they
1956 were not already referenced in the top level of the eval""ed code.
1960 Lexicals II: lexicals leaked at file scope into subroutines that
1961 were declared before the lexicals.
1965 Lexical warnings now propagating correctly between scopes
1966 and into C<eval "...">.
1970 C<use warnings qw(FATAL all)> did not work as intended. This has been
1975 warnings::enabled() now reports the state of $^W correctly if the caller
1976 isn't using lexical warnings.
1980 Line renumbering with eval and C<#line> now works.
1984 Fixed numerous memory leaks, especially in eval "".
1988 Localised tied variables no more leak memory
1991 tie my %tied_hash => 'Tie::StdHash';
1995 # Used to leak memory every time local() was called,
1996 # in a loop this added up.
1997 local($tied_hash{Foo}) = 1;
2001 Localised hash elements (and %ENV) are correctly unlocalised to not to
2002 exist, if that's what they were.
2006 tie my %tied_hash => 'Tie::StdHash';
2010 # Nothing has set the FOO element so far
2012 { local $tied_hash{FOO} = 'Bar' }
2014 # This used to print, but not now.
2015 print "exists!\n" if exists $tied_hash{FOO};
2017 As a side effect of this fix, tied hash interfaces B<must> define
2018 the EXISTS and DELETE methods.
2022 mkdir() now ignores trailing slashes in the directory name,
2023 as mandated by POSIX.
2027 Some versions of glibc have a broken modfl(). This affects builds
2028 with C<-Duselongdouble>. This version of Perl detects this brokenness
2029 and has a workaround for it. The glibc release 2.2.2 is known to have
2030 fixed the modfl() bug.
2034 Modulus of unsigned numbers now works (4063328477 % 65535 used to
2035 return 27406, instead of 27047).
2039 Some "not a number" warnings introduced in 5.6.0 eliminated to be
2040 more compatible with 5.005. Infinity is now recognised as a number.
2044 Numeric conversions did not recognize changes in the string value
2045 properly in certain circumstances.
2049 Attributes (like :shared) didn't work with our().
2053 our() variables will not cause "will not stay shared" warnings.
2057 "our" variables of the same name declared in two sibling blocks
2058 resulted in bogus warnings about "redeclaration" of the variables.
2059 The problem has been corrected.
2063 pack "Z" now correctly terminates the string with "\0".
2067 Fix password routines which in some shadow password platforms
2068 (e.g. HP-UX) caused getpwent() to return every other entry.
2072 The PERL5OPT environment variable (for passing command line arguments
2073 to Perl) didn't work for more than a single group of options.
2077 PERL5OPT with embedded spaces didn't work.
2081 printf() no longer resets the numeric locale to "C".
2085 C<qw(a\\b)> now parses correctly as C<'a\\b'>.
2089 pos() did not return the correct value within s///ge in earlier
2090 versions. This is now handled correctly.
2094 Printing quads (64-bit integers) with printf/sprintf now works
2095 without the q L ll prefixes (assuming you are on a quad-capable platform).
2099 Regular expressions on references and overloaded scalars now work.
2103 Right-hand side magic (GMAGIC) could in many cases such as string
2104 concatenation be invoked too many times.
2108 scalar() now forces scalar context even when used in void context.
2112 SOCKS support is now much more robust.
2116 sort() arguments are now compiled in the right wantarray context
2117 (they were accidentally using the context of the sort() itself).
2118 The comparison block is now run in scalar context, and the arguments
2119 to be sorted are always provided list context.
2123 Changed the POSIX character class C<[[:space:]]> to include the (very
2124 rarely used) vertical tab character. Added a new POSIX-ish character
2125 class C<[[:blank:]]> which stands for horizontal whitespace
2126 (currently, the space and the tab).
2130 The tainting behaviour of sprintf() has been rationalized. It does
2131 not taint the result of floating point formats anymore, making the
2132 behaviour consistent with that of string interpolation.
2136 Some cases of inconsistent taint propagation (such as within hash
2137 values) have been fixed.
2141 The RE engine found in Perl 5.6.0 accidentally pessimised certain kinds
2142 of simple pattern matches. These are now handled better.
2146 Regular expression debug output (whether through C<use re 'debug'>
2147 or via C<-Dr>) now looks better.
2151 Multi-line matches like C<"a\nxb\n" =~ /(?!\A)x/m> were flawed. The
2156 Use of $& could trigger a core dump under some situations. This
2161 The regular expression captured submatches ($1, $2, ...) are now
2162 more consistently unset if the match fails, instead of leaving false
2163 data lying around in them.
2167 readline() on files opened in "slurp" mode could return an extra "" at
2168 the end in certain situations. This has been corrected.
2172 Autovivification of symbolic references of special variables described
2173 in L<perlvar> (as in C<${$num}>) was accidentally disabled. This works
2178 Sys::Syslog ignored the C<LOG_AUTH> constant.
2182 All but the first argument of the IO syswrite() method are now optional.
2186 $AUTOLOAD, sort(), lock(), and spawning subprocesses
2187 in multiple threads simultaneously are now thread-safe.
2191 Tie::ARRAY SPLICE method was broken.
2195 Allow read-only string on left hand side of non-modifying tr///.
2199 If C<STDERR> is tied, warnings caused by C<warn> and C<die> now
2200 correctly pass to it.
2204 Several Unicode fixes.
2210 BOMs (byte order marks) in the beginning of Perl files
2211 (scripts, modules) should now be transparently skipped.
2212 UTF-16 (UCS-2) encoded Perl files should now be read correctly.
2216 The character tables have been updated to Unicode 3.2.0.
2220 Comparing with utf8 data does not magically upgrade non-utf8 data
2221 into utf8. (This was a problem for example if you were mixing data
2222 from I/O and Unicode data: your output might have got magically encoded
2227 Generating illegal Unicode code points like U+FFFE, or the UTF-16
2228 surrogates, now also generates an optional warning.
2232 C<IsAlnum>, C<IsAlpha>, and C<IsWord> now match titlecase.
2236 Concatenation with the C<.> operator or via variable interpolation,
2237 C<eq>, C<substr>, C<reverse>, C<quotemeta>, the C<x> operator,
2238 substitution with C<s///>, single-quoted UTF8, should now work.
2242 The C<tr///> operator now works. Note that the C<tr///CU>
2243 functionality has been removed (but see pack('U0', ...)).
2247 C<eval "v200"> now works.
2251 Perl 5.6.0 parsed m/\x{ab}/ incorrectly, leading to spurious warnings.
2252 This has been corrected.
2256 Zero entries were missing from the Unicode classes like C<IsDigit>.
2262 Large unsigned numbers (those above 2**31) could sometimes lose their
2263 unsignedness, causing bogus results in arithmetic operations.
2267 =head2 Platform Specific Changes and Fixes
2275 Perl now works on post-4.0 BSD/OSes.
2281 Setting C<$0> now works (as much as possible; see L<perlvar> for details).
2287 Numerous updates; currently synchronised with Cygwin 1.3.10.
2291 Previously DYNIX/ptx had problems in its Configure probe for non-blocking I/O.
2297 EPOC update after Perl 5.6.0. See README.epoc.
2303 Perl now works on post-3.0 FreeBSDs.
2309 README.hpux updated; C<Configure -Duse64bitall> now works;
2310 now uses HP-UX malloc instead of Perl malloc.
2316 Numerous compilation flag and hint enhancements; accidental mixing
2317 of 32-bit and 64-bit libraries (a doomed attempt) made much harder.
2327 Long doubles should now work (see INSTALL).
2331 Linux previously had problems related to sockaddrlen when using
2332 accept(), revcfrom() (in Perl: recv()), getpeername(), and getsockname().
2340 Compilation of the standard Perl distribution in MacOS Classic should
2341 now work if you have the Metrowerks development environment and
2342 the missing Mac-specific toolkit bits. Contact the macperl mailing
2349 MPE/iX update after Perl 5.6.0. See README.mpeix.
2353 NetBSD/threads: try installing the GNU pth (should be in the
2354 packages collection, or http://www.gnu.org/software/pth/),
2355 and Configure with -Duseithreads.
2361 Perl now works on NetBSD/sparc.
2367 Now works with usethreads (see INSTALL).
2373 64-bitness using the Sun Workshop compiler now works.
2379 The native build method requires at least VOS Release 14.5.0
2380 and GNU C++/GNU Tools 2.0.1 or later. The Perl pack function
2381 now maps overflowed values to +infinity and underflowed values
2386 Tru64 (aka Digital UNIX, aka DEC OSF/1)
2388 The operating system version letter now recorded in $Config{osvers}.
2389 Allow compiling with gcc (previously explicitly forbidden). Compiling
2390 with gcc still not recommended because buggy code results, even with
2397 Fixed various alignment problems that lead into core dumps either
2398 during build or later; no longer dies on math errors at runtime;
2399 now using full quad integers (64 bits), previously was using
2400 only 46 bit integers for speed.
2406 chdir() now works better despite a CRT bug; now works with MULTIPLICITY
2407 (see INSTALL); now works with Perl's malloc.
2409 The tainting of C<%ENV> elements via C<keys> or C<values> was previously
2410 unimplemented. It now works as documented.
2412 The C<waitpid> emulation has been improved. The worst bug (now fixed)
2413 was that a pid of -1 would cause a wildcard search of all processes on
2416 POSIX-style signals are now emulated much better on VMS versions prior
2419 The C<system> function and backticks operator have improved
2420 functionality and better error handling.
2422 File access tests now use current process privileges rather than the
2423 user's default privileges, which could sometimes result in a mismatch
2424 between reported access and actual access.
2426 There is a new C<kill> implementation based on C<sys$sigprc> that allows
2427 older VMS systems (pre-7.0) to use C<kill> to send signals rather than
2428 simply force exit. This implementation also allows later systems to
2429 call C<kill> from within a signal handler.
2431 Iterative logical name translations are now limited to 10 iterations in
2432 imitation of SHOW LOGICAL and other OpenVMS facilities.
2442 accept() no longer leaks memory.
2446 Borland C++ v5.5 is now a supported compiler that can build Perl.
2447 However, the generated binaries continue to be incompatible with those
2448 generated by the other supported compilers (GCC and Visual C++).
2452 Better chdir() return value for a non-existent directory.
2456 Duping socket handles with open(F, ">&MYSOCK") now works under Windows 9x.
2460 New %ENV entries now propagate to subprocesses.
2464 Current directory entries in %ENV are now correctly propagated to child
2469 $ENV{LIB} now used to search for libs under Visual C.
2473 fork() emulation has been improved in various ways, but still continues
2474 to be experimental. See L<perlfork> for known bugs and caveats.
2478 A failed (pseudo)fork now returns undef and sets errno to EAGAIN.
2482 Win32::GetCwd() correctly returns C:\ instead of C: when at the drive root.
2483 Other bugs in chdir() and Cwd::cwd() have also been fixed.
2487 HTML files will be installed in c:\perl\html instead of c:\perl\lib\pod\html
2491 The makefiles now provide a single switch to bulk-enable all the features
2492 enabled in ActiveState ActivePerl (a popular Win32 binary distribution).
2496 Allow REG_EXPAND_SZ keys in the registry.
2500 Can now send() from all threads, not just the first one.
2504 Fake signal handling reenabled, bugs and all.
2508 %SIG has been enabled under USE_ITHREADS, but its use is completely
2509 unsupported under all configurations.
2513 Less stack reserved per thread so that more threads can run
2514 concurrently. (Still 16M per thread.)
2518 C<< File::Spec->tmpdir() >> now prefers C:/temp over /tmp
2519 (works better when perl is running as service).
2523 Better UNC path handling under ithreads.
2527 wait(), waitpid() and backticks now return the correct exit status under
2532 Win64 compilation is now supported.
2536 winsock handle leak fixed.
2540 The Perl parser has been stress tested using both random input and
2541 Markov chain input and the few found crashes and lockups have been
2548 =head1 New or Changed Diagnostics
2554 The lexical warnings category "deprecated" is no longer a sub-category
2555 of the "syntax" category. It is now a top-level category in its own
2560 All regular expression compilation error messages are now hopefully
2561 easier to understand both because the error message now comes before
2562 the failed regex and because the point of failure is now clearly
2563 marked by a C<E<lt>-- HERE> marker.
2567 The various "opened only for", "on closed", "never opened" warnings
2568 drop the C<main::> prefix for filehandles in the C<main> package,
2569 for example C<STDIN> instead of C<main::STDIN>.
2573 The "Unrecognized escape" warning has been extended to include C<\8>,
2574 C<\9>, and C<\_>. There is no need to escape any of the C<\w> characters.
2578 Two new debugging options have been added: if you have compiled your
2579 Perl with debugging, you can use the -DT and -DR options to trace
2580 tokenising and to add reference counts to displaying variables,
2585 The debugger (perl5db.pl) has been modified to present a more
2586 consistent commands interface, via (CommandSet=580). perl5db.t was
2587 also added to test the changes, and as a placeholder for further tests.
2593 The debugger has a new C<dumpDepth> option to control the maximum
2594 depth to which nested structures are dumped. The C<x> command has
2595 been extended so that C<x N EXPR> dumps out the value of I<EXPR> to a
2596 depth of at most I<N> levels.
2600 The debugger can now show lexical variables if you have the CPAN
2601 module PadWalker installed.
2605 If an attempt to use a (non-blessed) reference as an array index
2606 is made, a warning is given.
2610 C<push @a;> and C<unshift @a;> (with no values to push or unshift)
2611 now give a warning. This may be a problem for generated and evaled
2616 If you try to L<perlfunc/pack> a number less than 0 or larger than 255
2617 using the C<"C"> format you will get an optional warning. Similarly
2618 for the C<"c"> format and a number less than -128 or more than 127.
2622 Certain regex modifiers such as C<(?o)> make sense only if applied to
2623 the entire regex. You will get an optional warning if you try to do
2628 Using arrays or hashes as references (e.g. C<< %foo->{bar} >>
2629 has been deprecated for a while. Now you will get an optional warning.
2633 Using C<sort> in scalar context now issues an optional warning.
2634 This didn't do anything useful, as the sort was not performed.
2638 =head1 Changed Internals
2644 perlapi.pod (a companion to perlguts) now attempts to document the
2649 You can now build a really minimal perl called microperl.
2650 Building microperl does not require even running Configure;
2651 C<make -f Makefile.micro> should be enough. Beware: microperl makes
2652 many assumptions, some of which may be too bold; the resulting
2653 executable may crash or otherwise misbehave in wondrous ways.
2654 For careful hackers only.
2658 Added rsignal(), whichsig(), do_join(), op_clear, op_null,
2659 ptr_table_clear(), ptr_table_free(), sv_setref_uv(), and several UTF-8
2660 interfaces to the publicised API. For the full list of the available
2661 APIs see L<perlapi>.
2665 Made possible to propagate customised exceptions via croak()ing.
2669 Now xsubs can have attributes just like subs. (Well, at least the
2670 built-in attributes.)
2674 dTHR and djSP have been obsoleted; the former removed (because it's
2675 a no-op) and the latter replaced with dSP.
2679 PERL_OBJECT has been completely removed.
2683 The MAGIC constants (e.g. C<'P'>) have been macrofied
2684 (e.g. C<PERL_MAGIC_TIED>) for better source code readability
2685 and maintainability.
2689 The regex compiler now maintains a structure that identifies nodes in
2690 the compiled bytecode with the corresponding syntactic features of the
2691 original regex expression. The information is attached to the new
2692 C<offsets> member of the C<struct regexp>. See L<perldebguts> for more
2693 complete information.
2697 The C code has been made much more C<gcc -Wall> clean. Some warning
2698 messages still remain in some platforms, so if you are compiling with
2699 gcc you may see some warnings about dubious practices. The warnings
2700 are being worked on.
2704 F<perly.c>, F<sv.c>, and F<sv.h> have now been extensively commented.
2708 Documentation on how to use the Perl source repository has been added
2709 to F<Porting/repository.pod>.
2713 There are now several profiling make targets.
2717 =head1 Security Vulnerability Closed
2719 (This change was already made in 5.7.0 but bears repeating here.)
2721 A potential security vulnerability in the optional suidperl component
2722 of Perl was identified in August 2000. suidperl is neither built nor
2723 installed by default. As of November 2001 the only known vulnerable
2724 platform is Linux, most likely all Linux distributions. CERT and
2725 various vendors and distributors have been alerted about the vulnerability.
2726 See http://www.cpan.org/src/5.0/sperl-2000-08-05/sperl-2000-08-05.txt
2727 for more information.
2729 The problem was caused by Perl trying to report a suspected security
2730 exploit attempt using an external program, /bin/mail. On Linux
2731 platforms the /bin/mail program had an undocumented feature which
2732 when combined with suidperl gave access to a root shell, resulting in
2733 a serious compromise instead of reporting the exploit attempt. If you
2734 don't have /bin/mail, or if you have 'safe setuid scripts', or if
2735 suidperl is not installed, you are safe.
2737 The exploit attempt reporting feature has been completely removed from
2738 Perl 5.8.0 (and the maintenance release 5.6.1, and it was removed also
2739 from all the Perl 5.7 releases), so that particular vulnerability
2740 isn't there anymore. However, further security vulnerabilities are,
2741 unfortunately, always possible. The suidperl functionality is most
2742 probably going to be removed in Perl 5.10. In any case, suidperl
2743 should only be used by security experts who know exactly what they are
2744 doing and why they are using suidperl instead of some other solution
2745 such as sudo ( see http://www.courtesan.com/sudo/ ).
2749 Several new tests have been added, especially for the F<lib> and F<ext>
2750 subsections. There are now about 65 000 individual tests (spread over
2751 about 700 test scripts), in the regression suite (5.6.1 has about
2752 11700 tests, in 258 test scripts) Many of the new tests are of course
2753 introduced by the new modules, but still in general Perl is now more
2756 Because of the large number of tests, running the regression suite
2757 will take considerably longer time than it used to: expect the suite
2758 to take up to 4-5 times longer to run than in perl 5.6. In a really
2759 fast machine you can hope to finish the suite in about 6-8 minutes
2762 The tests are now reported in a different order than in earlier Perls.
2763 (This happens because the test scripts from under t/lib have been moved
2764 to be closer to the library/extension they are testing.)
2766 =head1 Known Problems
2774 In AIX 4.2 Perl extensions that use C++ functions that use statics
2775 may have problems in that the statics are not getting initialized.
2776 In newer AIX releases this has been solved by linking Perl with
2777 the libC_r library, but unfortunately in AIX 4.2 the said library
2778 has an obscure bug where the various functions related to time
2779 (such as time() and gettimeofday()) return broken values, and
2780 therefore in AIX 4.2 Perl is not linked against the libC_r.
2784 vac 5.0.0.0 May Produce Buggy Code For Perl
2786 The AIX C compiler vac version 5.0.0.0 may produce buggy code,
2787 resulting in few random tests failing, but when the failing tests
2788 are run by hand, they succeed. We suggest upgrading to at least
2789 vac version 5.0.1.0, that has been known to compile Perl correctly.
2790 "lslpp -L|grep vac.C" will tell you the vac version. See README.aix.
2794 If building threaded Perl, you may get compilation warning from pp_sys.c:
2796 "pp_sys.c", line 4651.39: 1506-280 (W) Function argument assignment between types "unsigned char*" and "const void*" is not allowed.
2798 This is harmless; it is caused by the getnetbyaddr() and getnetbyaddr_r()
2799 having slightly different types for their first argument.
2805 The following tests fail on 5.8.0 Perl in BeOS Personal 5.03:
2807 t/op/lfs............................FAILED at test 17
2808 t/op/magic..........................FAILED at test 24
2809 ext/Fcntl/t/syslfs..................FAILED at test 17
2810 ext/File/Glob/t/basic...............FAILED at test 3
2811 ext/POSIX/t/sigaction...............FAILED at test 13
2812 ext/POSIX/t/waitpid.................FAILED at test 1
2813 lib/Tie/File/t/16_handle............FAILED at test 39
2815 See L<perlbeos> (README.beos) for more details.
2817 =head2 ext/threads/t/libc
2819 If this test fails, it indicates that your libc (C library) is not
2820 threadsafe. This particular test stress tests the localtime() call to
2821 find out whether it is threadsafe. See L<perlthrtut> for more information.
2823 =head2 FreeBSD Failing locale Test 117 For ISO8859-15 Locales
2825 The ISO8859-15 locales may fail the locale test 117 in FreeBSD.
2826 This is caused by the characters \xFF (y with diaeresis) and \xBE
2827 (Y with diaeresis) not behaving correctly when being matched
2830 =head2 Modifying $_ Inside for(..)
2834 works without complaint. It shouldn't. (You should be able to
2835 modify only lvalue elements inside the loops.) You can see the
2836 correct behaviour by replacing the 1..5 with 1, 2, 3, 4, 5.
2838 =head2 mod_perl 1.26 Doesn't Build With Threaded Perl
2840 Use mod_perl 1.27 or higher.
2842 =head2 lib/ftmp-security tests warn 'system possibly insecure'
2844 Don't panic. Read INSTALL 'make test' section instead.
2846 =head2 HP-UX lib/posix Subtest 9 Fails When LP64-Configured
2848 If perl is configured with -Duse64bitall, the successful result of the
2849 subtest 10 of lib/posix may arrive before the successful result of the
2850 subtest 9, which confuses the test harness so much that it thinks the
2853 =head2 Linux with glibc 2.2.5 fails t/op/int subtest #6 with -Duse64bitint
2855 This is a known bug in the glibc 2.2.5 with long long integers.
2856 ( http://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=65612 )
2858 =head2 Linux With Sfio Fails op/misc Test 48
2864 Please remember to set your environment variable LC_ALL to "C"
2865 (setenv LC_ALL C) before running "make test" to avoid a lot of
2866 warnings about the broken locales of Mac OS X.
2868 The following tests are known to fail:
2870 Failed Test Stat Wstat Total Fail Failed List of Failed
2871 -------------------------------------------------------------------------
2872 ../ext/DB_File/t/db-btree.t 0 11 ?? ?? % ??
2873 ../ext/DB_File/t/db-recno.t 149 3 2.01% 61 63 65
2875 If you are building on a UFS partition, you will also probably see
2876 t/op/stat.t subtest #9 fail. This is caused by Darwin's UFS not
2877 supporting inode change time.
2879 Also the ext/POSIX/t/posix.t subtest #10 fails but it is skipped for
2880 now because the failure is Apple's fault, not Perl's (blocked signals
2883 If you Configure with ithreads, ext/threads/t/libc.t will fail, again
2884 not Perl's fault-- the libc of Mac OS X is not threadsafe (in this
2885 particular test the localtime() call is found to be threadunsafe.)
2887 =head2 op/sprintf tests 91, 129, and 130
2889 The op/sprintf tests 91, 129, and 130 are known to fail on some platforms.
2890 Examples include any platform using sfio, and Compaq/Tandem's NonStop-UX.
2892 The test 91 is known to fail at QNX6 (nto), because C<sprintf '%e',0>
2893 incorrectly produces C<0.000000e+0> instead of C<0.000000e+00>.
2895 For the tests 129 and 130 the failing platforms do not comply with
2896 the ANSI C Standard, line 19ff on page 134 of ANSI X3.159 1989 to
2897 be exact. (They produce something other than "1" and "-1" when
2898 formatting 0.6 and -0.6 using the printf format "%.0f", most often
2899 they produce "0" and "-0".)
2903 In case you are still using Solaris 2.5 (aka SunOS 5.5), you may
2904 experience failures (the test core dumping) in lib/locale.t.
2905 The suggested cure is to upgrade your Solaris.
2909 When Perl is built using the native build process on VOS Release
2910 14.5.0 and GNU C++/GNU Tools 2.0.1, all attempted tests either
2911 pass or result in TODO (ignored) failures.
2913 =head2 Term::ReadKey not working on Win32
2915 Use Term::ReadKey 2.20 or later.
2917 =head2 Failure of Thread (5.005-style) tests
2919 B<Note that support for 5.005-style threading is deprecated,
2920 experimental and practically unsupported. In 5.10 it is expected
2923 The following tests are known to fail due to fundamental problems in
2924 the 5.005 threading implementation. These are not new failures--Perl
2925 5.005_0x has the same bugs, but didn't have these tests.
2927 ../ext/List/Util/t/first.t 255 65280 7 4 57.14% 2 5-7
2928 ../lib/English.t 2 512 54 2 3.70% 2-3
2929 ../lib/Filter/Simple/t/data.t 6 3 50.00% 1-3
2930 ../lib/Filter/Simple/t/filter_onl 9 3 33.33% 1-2 5
2931 ../lib/autouse.t 10 1 10.00% 4
2932 op/flip.t 15 1 6.67% 15
2934 These failures are unlikely to get fixed as the 5.005-style threads
2935 are considered fundamentally broken. (Basically what happens is that
2936 competing threads can corrupt shared global state.)
2940 ../lib/Math/Trig.t 26 1 3.85% 25
2941 ../lib/warnings.t 470 1 0.21% 429
2943 The Trig.t failure is caused by the slighly differing (from IEEE)
2944 floating point implementation of UNICOS. The warnings.t failure is
2945 also related: the test assumes a certain floating point output format,
2946 this assumption fails in UNICOS.
2954 During Configure the test
2956 Guessing which symbols your C compiler and preprocessor define...
2958 will probably fail with error messages like
2960 CC-20 cc: ERROR File = try.c, Line = 3
2961 The identifier "bad" is undefined.
2963 bad switch yylook 79bad switch yylook 79bad switch yylook 79bad switch yylook 79#ifdef A29K
2966 CC-65 cc: ERROR File = try.c, Line = 3
2967 A semicolon is expected at this point.
2969 This is caused by a bug in awk utility of UNICOS/mk. You can ignore
2970 the error, but it does cause a slight problem: you cannot fully
2971 benefit from the h2ph utility (see L<h2ph>) that can be used to
2972 convert C headers to Perl libraries, mainly used to be able to access
2973 from Perl the constants defined using C preprocessor, cpp. Because of
2974 the above error parts of the converted headers will be invisible.
2975 Luckily, these days the need for h2ph is rare.
2979 If building Perl with the interpreter threads (ithreads), the
2980 getgrent(), getgrnam(), and getgrgid() functions cannot return the
2981 list of the group members due to a bug in the multithreaded support of
2982 UNICOS/mk. What this means that in list context the functions will
2983 return only three values, not four.
2989 There are a few known test failures, see L<perluts>.
2993 There should be no reported test failures with a default configuration,
2994 though there are a number of tests marked TODO that point to areas
2995 needing further debugging and/or porting work.
2999 In multi-CPU boxes there are some problems with the I/O buffering:
3000 some output may appear twice.
3002 =head2 XML::Parser not working
3004 Use XML::Parser 2.31 or later.
3006 =head2 z/OS (OS/390)
3008 z/OS has rather many test failures but the situation is actually
3009 better than it was in 5.6.0, it's just that so many new modules and
3010 tests have been added.
3012 Failed Test Stat Wstat Total Fail Failed List of Failed
3013 ---------------------------------------------------------------------------
3014 ../ext/Data/Dumper/t/dumper.t 357 8 2.24% 311 314 325 327
3016 ../ext/IO/lib/IO/t/io_unix.t 5 4 80.00% 2-5
3017 ../ext/Storable/t/downgrade.t 12 3072 169 12 7.10% 14-15 46-47 78-79
3019 ../lib/ExtUtils/t/Constant.t 121 30976 48 48 100.00% 1-48
3020 ../lib/ExtUtils/t/Embed.t 9 9 100.00% 1-9
3021 op/pat.t 910 7 0.77% 665 776 785 832-
3023 op/sprintf.t 224 3 1.34% 98 100 136
3024 op/tr.t 97 5 5.15% 63 71-74
3025 uni/fold.t 780 6 0.77% 61 169 196 661
3028 The dumper.t and downgrade.t are problems in the tests, the io_unix
3029 and sprintf are problems in the USS (UDP sockets and printf formats).
3030 The pat, tr, and fold are genuine Perl problems caused by EBCDIC (and
3031 in the pat and fold cases, combining that with Unicode). The Constant
3032 and Embed are probably problems in the tests (since they test Perl's
3033 ability to build extensions, and that seems to be working reasonably well.)
3035 =head2 Localising Tied Arrays and Hashes Is Broken
3039 doesn't work as one would expect: the old value is restored
3040 incorrectly. This will be changed in a future release, but we don't
3041 know yet which the new semantics will exactly be. In any case the
3042 change will break existing code that relies on the current
3043 (ill-defined) semantics, so just avoid doing this in general.
3045 =head2 Self-tying Problems
3047 Self-tying of arrays and hashes is broken in rather deep and
3048 hard-to-fix ways. As a stop-gap measure to avoid people from getting
3049 frustrated at the mysterious results (core dumps, most often) it is
3050 for now forbidden (you will get a fatal error even from an attempt).
3052 Self-tying of globs is broken, but not disabled.
3054 Self-tying of scalars and IO works.
3056 =head2 Building Extensions Can Fail Because Of Largefiles
3058 Some extensions like mod_perl are known to have issues with
3059 `largefiles', a change brought by Perl 5.6.0 in which file offsets
3060 default to 64 bits wide, where supported. Modules may fail to compile
3061 at all or compile and work incorrectly. Currently there is no good
3062 solution for the problem, but Configure now provides appropriate
3063 non-largefile ccflags, ldflags, libswanted, and libs in the %Config
3064 hash (e.g., $Config{ccflags_nolargefiles}) so the extensions that are
3065 having problems can try configuring themselves without the
3066 largefileness. This is admittedly not a clean solution, and the
3067 solution may not even work at all. One potential failure is whether
3068 one can (or, if one can, whether it's a good idea) link together at
3069 all binaries with different ideas about file offsets, all this is
3072 =head2 Unicode Support on EBCDIC Still Spotty
3074 Though mostly working, Unicode support still has problem spots on
3075 EBCDIC platforms. One such known spot are the C<\p{}> and C<\P{}>
3076 regular expression constructs for code points less than 256: the
3077 C<pP> are testing for Unicode code points, not knowing about EBCDIC.
3079 =head2 The Compiler Suite Is Still Very Experimental
3081 The compiler suite is slowly getting better but it continues to be
3082 highly experimental. Use in production environments is discouraged.
3084 =head2 The Long Double Support Is Still Experimental
3086 The ability to configure Perl's numbers to use "long doubles",
3087 floating point numbers of hopefully better accuracy, is still
3088 experimental. The implementations of long doubles are not yet
3089 widespread and the existing implementations are not quite mature
3090 or standardised, therefore trying to support them is a rare
3091 and moving target. The gain of more precision may also be offset
3092 by slowdown in computations (more bits to move around, and the
3093 operations are more likely to be executed by less optimised
3096 =head2 Seen In Perl 5.7 But Gone Now
3098 C<Time::Piece> (previously known as C<Time::Object>) was removed
3099 because it was felt that it didn't have enough value in it to be a
3100 core module. It is still a useful module, though, and is available
3103 Perl 5.8 unfortunately does not build anymore on AmigaOS,
3104 this broke at some point accidentally. Since there are not that many
3105 Amiga developers available, we could not get this fixed and tested in
3108 =head1 Reporting Bugs
3110 If you find what you think is a bug, you might check the articles
3111 recently posted to the comp.lang.perl.misc newsgroup and the perl
3112 bug database at http://bugs.perl.org/ There may also be
3113 information at http://www.perl.com/ , the Perl Home Page.
3115 If you believe you have an unreported bug, please run the B<perlbug>
3116 program included with your release. Be sure to trim your bug down
3117 to a tiny but sufficient test case. Your bug report, along with the
3118 output of C<perl -V>, will be sent off to perlbug@perl.org to be
3119 analysed by the Perl porting team.
3123 The F<Changes> file for exhaustive details on what changed.
3125 The F<INSTALL> file for how to build Perl.
3127 The F<README> file for general stuff.
3129 The F<Artistic> and F<Copying> files for copyright information.
3133 Written by Jarkko Hietaniemi <F<jhi@iki.fi>>.