3 perldelta - what is new for perl v5.8.0
7 This document describes differences between the 5.6.0 release and the
10 =head1 Incompatible Changes
12 =head2 64-bit platforms and malloc
14 If your pointers are 64 bits wide, the Perl malloc is no more being
15 used because it does not work well with 8-byte pointers. Also,
16 usually the system mallocs on such platforms are much better optimized
17 for such large memory models than the Perl malloc. Some memory-hungry
18 Perl applications like the PDL don't work well with Perl's malloc.
19 Finally, other applications than Perl (like modperl) tend to prefer
20 the system malloc. Such platforms include Alpha and 64-bit HPPA,
23 =head2 AIX Dynaloading
25 The AIX dynaloading now uses in AIX releases 4.3 and newer the native
26 dlopen interface of AIX instead of the old emulated interface. This
27 change will probably break backward compatibility with compiled
28 modules. The change was made to make Perl more compliant with other
29 applications like modperl which are using the AIX native interface.
31 =head2 Socket Extension Dynamic in VMS
33 The Socket extension is now dynamically loaded instead of being
34 statically built in. This may or may not be a problem with ancient
35 TCP/IP stacks of VMS: we do not know since we weren't able to test
36 Perl in such configurations.
38 =head2 Different Definition of the Unicode Character Classes \p{In...}
40 As suggested by the Unicode consortium, the Unicode character classes
41 now prefer I<scripts> as opposed to I<blocks> (as defined by Unicode);
42 in Perl, when the C<\p{In....}> and the C<\p{In....}> regular expression
43 constructs are used. This has changed the definition of some of those
46 The difference between scripts and blocks is that scripts are the
47 glyphs used by a language or a group of languages, while the blocks
48 are more artificial groupings of 256 characters based on the Unicode
51 In general this change results in more inclusive Unicode character
52 classes, but changes to the other direction also do take place:
53 for example while the script C<Latin> includes all the Latin
54 characters and their various diacritic-adorned versions, it
55 does not include the various punctuation or digits (since they
56 are not solely C<Latin>).
58 Changes in the character class semantics may have happened if a script
59 and a block happen to have the same name, for example C<Hebrew>.
60 In such cases the script wins and C<\p{InHebrew}> now means the script
61 definition of Hebrew. The block definition in still available,
62 though, by appending C<Block> to the name: C<\p{InHebrewBlock}> means
63 what C<\p{InHebrew}> meant in perl 5.6.0. For the full list
64 of affected character classes, see L<perlunicode/Blocks>.
66 =head2 Perl Parser Stress Tested
68 The Perl parser has been stress tested using both random input and
69 Markov chain input and the few found crashes and lockups have been
72 =head2 REF(...) Instead Of SCALAR(...)
74 A reference to a reference now stringify as "REF(0x81485ec)" instead
75 of "SCALAR(0x81485ec)" in order to be more consistent with the return
84 The semantics of bless(REF, REF) were unclear and until someone proves
85 it to make some sense, it is forbidden.
89 The obsolete chat2 library that should never have been allowed
90 to escape the laboratory has been decommissioned.
94 The very dusty examples in the eg/ directory have been removed.
95 Suggestions for new shiny examples welcome but the main issue is that
96 the examples need to be documented, tested and (most importantly)
101 The (bogus) escape sequences \8 and \9 now give an optional warning
102 ("Unrecognized escape passed through"). There is no need to \-escape
107 The list of filenames from glob() (or <...>) is now by default sorted
108 alphabetically to be csh-compliant. (bsd_glob() does still sort platform
109 natively, ASCII or EBCDIC, unless GLOB_ALPHASORT is specified.)
113 Although "you shouldn't do that", it was possible to write code that
114 depends on Perl's hashed key order (Data::Dumper does this). The new
115 algorithm "One-at-a-Time" produces a different hashed key order.
116 More details are in L</"Performance Enhancements">.
120 lstat(FILEHANDLE) now gives a warning because the operation makes no sense.
121 In future releases this may become a fatal error.
125 The C<package;> syntax (C<package> without an argument has been
126 deprecated. Its semantics were never that clear and its
127 implementation even less so. If you have used that feature to
128 disallow all but fully qualified variables, C<use strict;> instead.
132 The unimplemented POSIX regex features [[.cc.]] and [[=c=]] are still
133 recognised but now cause fatal errors. The previous behaviour of
134 ignoring them by default and warning if requested was unacceptable
135 since it, in a way, falsely promised that the features could be used.
139 The current user-visible implementation of pseudo-hashes (the weird
140 use of the first array element) is deprecated starting from Perl 5.8.0
141 and will be removed in Perl 5.10.0, and the feature will be
142 implemented differently. Not only is the current interface rather
143 ugly, but the current implementation slows down normal array and hash
144 use quite noticeably. The C<fields> pragma interface will remain
149 The syntaxes C<< @a->[...] >> and C<< %h->{...}>> have now been deprecated.
153 After years of trying the suidperl is considered to be too complex to
154 ever be considered truly secure. The suidperl functionality is likely
155 to be removed in a future release.
159 The long deprecated uppercase aliases for the string comparison
160 operators (EQ, NE, LT, LE, GE, GT) have now been removed.
164 The tr///C and tr///U features have been removed and will not return;
165 the interface was a mistake. Sorry about that. For similar
166 functionality, see pack('U0', ...) and pack('C0', ...).
170 =head1 Core Enhancements
172 =head2 PerlIO is Now The Default
178 IO is now by default done via PerlIO rather than system's "stdio".
179 PerlIO allows "layers" to be "pushed" onto a file handle to alter the
180 handle's behaviour. Layers can be specified at open time via 3-arg
183 open($fh,'>:crlf :utf8', $path) || ...
185 or on already opened handles via extended C<binmode>:
187 binmode($fh,':encoding(iso-8859-7)');
189 The built-in layers are: unix (low level read/write), stdio (as in
190 previous Perls), perlio (re-implementation of stdio buffering in a
191 portable manner), crlf (does CRLF <=> "\n" translation as on Win32,
192 but available on any platform). A mmap layer may be available if
193 platform supports it (mostly UNIXes).
195 Layers to be applied by default may be specified via the 'open' pragma.
197 See L</"Installation and Configuration Improvements"> for the effects
198 of PerlIO on your architecture name.
202 File handles can be marked as accepting Perl's internal encoding of Unicode
203 (UTF-8 or UTF-EBCDIC depending on platform) by a pseudo layer ":utf8" :
205 open($fh,">:utf8","Uni.txt");
207 Note for EBCDIC users: the pseudo layer ":utf8" is erroneously named
208 for you since it's not UTF-8 what you will be getting but instead
209 UTF-EBCDIC. See L<perlunicode>, L<utf8>, and
210 http://www.unicode.org/unicode/reports/tr16/ for more information.
211 In future releases this naming may change.
215 File handles can translate character encodings from/to Perl's internal
216 Unicode form on read/write via the ":encoding()" layer.
220 File handles can be opened to "in memory" files held in Perl scalars via:
222 open($fh,'>', \$variable) || ...
226 Anonymous temporary files are available without need to
227 'use FileHandle' or other module via
229 open($fh,"+>", undef) || ...
231 That is a literal undef, not an undefined value.
235 The list form of C<open> is now implemented for pipes (at least on UNIX):
237 open($fh,"-|", 'cat', '/etc/motd')
239 creates a pipe, and runs the equivalent of exec('cat', '/etc/motd') in
244 =head2 Signals Are Now Safe
246 Perl used to be fragile in that signals arriving at inopportune moments
247 could corrupt Perl's internal state. Now Perl postpones handling of
248 signals until it's safe.
250 =head2 Unicode Overhaul
252 Unicode in general should be now much more usable than in Perl 5.6.0
253 (or even in 5.6.1). Unicode can be used in hash keys, Unicode in
254 regular expressions should work now, Unicode in tr/// should work now,
255 Unicode in I/O should work now.
261 The Unicode Character Database coming with Perl has been upgraded
262 to Unicode 3.1.1. For more information, see http://www.unicode.org/.
266 For developers interested in enhancing Perl's Unicode capabilities:
267 almost all the UCD files are included with the Perl distribution in
268 the lib/unicore subdirectory. The most notable omission, for space
269 considerations, is the Unihan database.
273 The Unicode character classes \p{Blank} and \p{SpacePerl} have been
274 added. "Blank" is like C isblank(), that is, it contains only
275 "horizontal whitespace" (the space character is, the newline isn't),
276 and the "SpacePerl" is the Unicode equivalent of C<\s> (\p{Space}
277 isn't, since that includes the vertical tabulator character, whereas
282 =head2 Understanding of Numbers
284 In general a lot of fixing has happened in the area of Perl's
285 understanding of numbers, both integer and floating point. Since in
286 many systems the standard number parsing functions like C<strtoul()>
287 and C<atof()> seem to have bugs, Perl tries to work around their
288 deficiencies. This results hopefully in more accurate numbers.
290 Perl now tries internally to use integer values in numeric conversions
291 and basic arithmetics (+ - * /) if the arguments are integers, and
292 tries also to keep the results stored internally as integers.
293 This change leads into often slightly faster and always less lossy
294 arithmetics. (Previously Perl always preferred floating point numbers
297 =head2 Miscellaneous Enhancements
303 AUTOLOAD is now lvaluable, meaning that you can add the :lvalue attribute
304 to AUTOLOAD subroutines and you can assign to the AUTOLOAD return value.
308 C<perl -d:Module=arg,arg,arg> now works (previously one couldn't pass
309 in multiple arguments.)
313 END blocks are now run even if you exit/die in a BEGIN block.
314 Internally, the execution of END blocks is now controlled by
315 PL_exit_flags & PERL_EXIT_DESTRUCT_END. This enables the new
316 behaviour for Perl embedders. This will default in 5.10. See
321 Formats now support zero-padded decimal fields.
325 Lvalue subroutines can now return C<undef> in list context.
329 A new special regular expression variable has been introduced:
330 C<$^N>, which contains the most-recently closed group (submatch).
334 C<no Module;> now works even if there is no "sub unimport" in the Module.
338 The numerical comparison operators return C<undef> if either operand
339 is a NaN. Previously the behaviour was unspecified.
343 The following builtin functions are now overridable: each(), keys(),
344 pop(), push(), shift(), splice(), unshift().
348 C<pack('U0a*', ...)> can now be used to force a string to UTF8.
352 my __PACKAGE__ $obj now works.
356 The printf() and sprintf() now support parameter reordering using the
357 C<%\d+\$> and C<*\d+\$> syntaxes. For example
359 print "%2\$s %1\$s\n", "foo", "bar";
361 will print "bar foo\n"; This feature helps in writing
362 internationalised software.
366 prototype(\&) is now available.
370 prototype(\[$@%&]) is now available to implicitly create references
371 (useful for example if you want to emulate the tie() interface).
375 UNTIE method is now recognised.
379 L<utime> now supports C<utime undef, undef, @files> to change the
380 file timestamps to the current time.
384 The rules for allowing underscores (underbars) in numeric constants
385 have been relaxed and simplified: now you can have an underscore
386 simply B<between digits>.
390 =head1 Modules and Pragmata
392 =head2 New Modules and Pragmata
398 C<Attribute::Handlers> allows a class to define attribute handlers.
401 use Attribute::Handlers;
402 sub Wolf :ATTR(SCALAR) { print "howl!\n" }
404 # later, in some package using or inheriting from MyPack...
406 my MyPack $Fluffy : Wolf; # the attribute handler Wolf will be called
408 Both variables and routines can have attribute handlers. Handlers can
409 be specific to type (SCALAR, ARRAY, HASH, or CODE), or specific to the
410 exact compilation phase (BEGIN, CHECK, INIT, or END).
414 B<B::Concise> is a new compiler backend for walking the Perl syntax
415 tree, printing concise info about ops, from Stephen McCamant. The
416 output is highly customisable. See L<B::Concise>.
420 C<Class::ISA> for reporting the search path for a class's ISA tree,
421 by Sean Burke, has been added. See L<Class::ISA>.
425 C<Cwd> has now a split personality: if possible, an XS extension is
426 used, (this will hopefully be faster, more secure, and more robust)
427 but if not possible, the familiar Perl implementation is used.
431 C<Devel::PPPort>, originally from Kenneth Albanowski and now
432 maintained by Paul Marquess, has been added. It is primarily used
433 by C<h2xs> to enhance portability of of XS modules between different
438 C<Digest>, frontend module for calculating digests (checksums), from
439 Gisle Aas, has been added. See L<Digest>.
443 C<Digest::MD5> for calculating MD5 digests (checksums) as defined in
444 RFC 1321, from Gisle Aas, has been added. See L<Digest::MD5>.
446 use Digest::MD5 'md5_hex';
448 $digest = md5_hex("Thirsty Camel");
450 print $digest, "\n"; # 01d19d9d2045e005c3f1b80e8b164de1
452 NOTE: the C<MD5> backward compatibility module is deliberately not
453 included since its further use is discouraged.
457 C<Encode>, by Nick Ing-Simmons, provides a mechanism to translate
458 between different character encodings. Support for Unicode,
459 ISO-8859-*, ASCII, CP*, KOI8-R, and three variants of EBCDIC are
460 compiled in to the module. Several other encodings (like Japanese,
461 Chinese, and MacIntosh encodings) are included and will be loaded at
462 runtime. See L<Encode>.
464 Any encoding supported by Encode module is also available to the
465 ":encoding()" layer if PerlIO is used.
469 C<I18N::Langinfo> can be use to query locale information.
470 See L<I18N::Langinfo>.
474 C<I18N::LangTags> has functions for dealing with RFC3066-style
475 language tags, by Sean Burke. See L<I18N::LangTags>.
479 C<ExtUtils::Constant> is a new tool for extension writers for
480 generating XS code to import C header constants, by Nicholas Clark.
481 See L<ExtUtils::Constant>.
485 C<Filter::Simple> is an easy-to-use frontend to Filter::Util::Call,
486 from Damian Conway. See L<Filter::Simple>.
492 use Filter::Simple sub {
493 while (my ($from, $to) = splice @_, 0, 2) {
502 use MyFilter qr/red/ => 'green';
504 print "red\n"; # this code is filtered, will print "green\n"
505 print "bored\n"; # this code is filtered, will print "bogreen\n"
509 print "red\n"; # this code is not filtered, will print "red\n"
513 C<File::Temp> allows one to create temporary files and directories in
514 an easy, portable, and secure way, by Tim Jenness. See L<File::Temp>.
518 C<Filter::Util::Call> provides you with the framework to write
519 I<Source Filters> in Perl, from Paul Marquess. For most uses the
520 frontend Filter::Simple is to be preferred. See L<Filter::Util::Call>.
524 L<libnet> is a collection of perl5 modules related to network
525 programming, from Graham Barr. See L<Net::FTP>, L<Net::NNTP>,
526 L<Net::Ping>, L<Net::POP3>, L<Net::SMTP>, and L<Net::Time>.
528 Perl installation leaves libnet unconfigured, use F<libnetcfg> to configure.
532 C<List::Util> is a selection of general-utility list subroutines, like
533 sum(), min(), first(), and shuffle(), by Graham Barr. See L<List::Util>.
537 C<Locale::Constants>, C<Locale::Country>, C<Locale::Currency>, and
538 C<Locale::Language>, from Neil Bowers, have been added. They provide the
539 codes for various locale standards, such as "fr" for France, "usd" for
540 US Dollar, and "jp" for Japanese.
544 $country = code2country('jp'); # $country gets 'Japan'
545 $code = country2code('Norway'); # $code gets 'no'
547 See L<Locale::Constants>, L<Locale::Country>, L<Locale::Currency>,
548 and L<Locale::Language>.
552 C<Locale::Maketext> is localization framework from Sean Burke. See
553 L<Locale::Maketext>, and L<Locale::Maketext::TPJ13>. The latter is an
554 article about software localization, originally published in The Perl
555 Journal #13, republished here with kind permission.
559 C<Memoize> can make your functions faster by trading space for time,
560 from Mark-Jason Dominus. See L<Memoize>.
564 C<MIME::Base64> allows you to encode data in base64, from Gisle Aas,
565 as defined in RFC 2045 - I<MIME (Multipurpose Internet Mail
570 $encoded = encode_base64('Aladdin:open sesame');
571 $decoded = decode_base64($encoded);
573 print $encoded, "\n"; # "QWxhZGRpbjpvcGVuIHNlc2FtZQ=="
579 C<MIME::QuotedPrint> allows you to encode data in quoted-printable
580 encoding, as defined in RFC 2045 - I<MIME (Multipurpose Internet Mail
581 Extensions)>, from Gisle Aas.
583 use MIME::QuotedPrint;
585 $encoded = encode_qp("Smiley in Unicode: \x{263a}");
586 $decoded = decode_qp($encoded);
588 print $encoded, "\n"; # "Smiley in Unicode: =263A"
590 MIME::QuotedPrint has been enhanced to provide the basic methods
591 necessary to use it with PerlIO::Via as in :
593 use MIME::QuotedPrint;
594 open($fh,">Via(MIME::QuotedPrint)",$path)
596 See L<MIME::QuotedPrint>.
600 C<NEXT> is pseudo-class for method redispatch, from Damian Conway.
605 C<open> is a new pragma for setting the default I/O disciplines
610 C<PerlIO::Scalar> provides the implementation of IO to "in memory"
611 Perl scalars as discussed above, from Nick Ing-Simmons. It also
612 serves as an example of a loadable PerlIO layer. Other future
613 possibilities include PerlIO::Array and PerlIO::Code.
614 See L<PerlIO::Scalar>.
618 C<PerlIO::Via> acts as a PerlIO layer and wraps PerlIO layer
619 functionality provided by a class (typically implemented in perl
620 code), from Nick Ing-Simmons.
622 use MIME::QuotedPrint;
623 open($fh,">Via(MIME::QuotedPrint)",$path)
625 This will automatically convert everything output to C<$fh>
626 to Quoted-Printable. See L<PerlIO::Via>.
630 C<Pod::ParseLink>, by Russ Allbery, has been added,
631 to parse L<> links in pods as described in the new
636 C<Pod::Text::Overstrike>, by Joe Smith, has been added.
637 It converts POD data to formatted overstrike text.
638 See L<Pod::Text::Overstrike>.
642 C<Scalar::Util> is a selection of general-utility scalar subroutines,
643 like blessed(), reftype(), and tainted(). See L<Scalar::Util>.
647 C<sort> is a new pragma for controlling the behaviour of sort().
651 C<Storable> gives persistence to Perl data structures by allowing the
652 storage and retrieval of Perl data to and from files in a fast and
653 compact binary format, from Raphael Manfredi. See L<Storable>.
657 C<Switch>, from Damian Conway, has been added. Just by saying
661 you have C<switch> and C<case> available in Perl.
667 case 1 { print "number 1" }
668 case "a" { print "string a" }
669 case [1..10,42] { print "number in list" }
670 case (@array) { print "number in list" }
671 case /\w+/ { print "pattern" }
672 case qr/\w+/ { print "pattern" }
673 case (%hash) { print "entry in hash" }
674 case (\%hash) { print "entry in hash" }
675 case (\&sub) { print "arg to subroutine" }
676 else { print "previous case not true" }
683 C<Test::More> is yet another framework for writing test scripts,
684 more extensive than Test::Simple, by Michael Schwern. See L<Test::More>.
688 C<Test::Simple> has the- basic utilities for writing tests, by Michael
689 Schwern. See L<Test::Simple>.
693 C<Text::Balanced> has been added, for extracting delimited text
694 sequences from strings, from Damian Conway.
696 use Text::Balanced 'extract_delimited';
698 ($a, $b) = extract_delimited("'never say never', he never said", "'", '');
700 $a will be "'never say never'", $b will be ', he never said'.
702 In addition to extract_delimited() there are also extract_bracketed(),
703 extract_quotelike(), extract_codeblock(), extract_variable(),
704 extract_tagged(), extract_multiple(), gen_delimited_pat(), and
705 gen_extract_tagged(). With these you can implement rather advanced
706 parsing algorithms. See L<Text::Balanced>.
710 C<threads> is an interface to interpreter threads, by Arthur Bergman.
711 Interpreter threads (ithreads) is the new thread model introduced in
712 Perl 5.6 but only available as an internal interface for extension
713 writers (and for Win32 Perl for C<fork()> emulation). See L<threads>.
717 C<threads::shared> allows data sharing for interpreter threads, from
718 Arthur Bergman. In the ithreads model any data sharing between
719 threads must be explicit, as opposed to the old 5.005 thread model
720 where data sharing was implicit. See L<threads::shared>.
724 C<Tie::RefHash::Nestable>, by Edward Avis, allows storing hash
725 references (unlike the standard Tie::RefHash) The module is contained
726 within Tie::RefHash, see L<Tie::RefHash>.
730 C<Time::HiRes> provides high resolution timing (ualarm, usleep,
731 and gettimeofday), from Douglas E. Wegscheid. See L<Time::HiRes>.
735 C<Unicode::UCD> offers a querying interface to the Unicode Character
736 Database. See L<Unicode::UCD>.
740 C<Unicode::Collate> implements the UCA (Unicode Collation Algorithm)
741 for sorting Unicode strings, by SADAHIRO Tomoyuki. See L<Unicode::Collate>.
745 C<Unicode::Normalize> implements the various Unicode normalization
746 forms, by SADAHIRO Tomoyuki. See L<Unicode::Normalize>.
750 C<XS::Typemap>, by Tim Jenness, is a test extension that exercises XS
751 typemaps. Nothing gets installed but for extension writers the code
756 =head2 Updated And Improved Modules and Pragmata
762 The following independently supported modules have been updated to the
763 newest versions from CPAN: CGI, CPAN, DB_File, File::Spec, File::Temp,
764 Getopt::Long, Math::BigFloat, Math::BigInt, the podlators bundle
765 (Pod::Man, Pod::Text), Pod::LaTeX, Pod::Parser, Storable,
766 Term::ANSIColor, Test, Text-Tabs+Wrap.
770 The attributes::reftype() now works on tied arguments.
774 AutoLoader can now be disabled with C<no AutoLoader;>,
778 B::Deparse has been significantly enhanced. It now can deparse almost
779 all of the standard test suite (so that the tests still succeed).
780 There is a make target "test.deparse" for trying this out.
784 Class::Struct can now define the classes in compile time.
788 Class::Struct now assigns the array/hash element if the accessor
789 is called with an array/hash element as the B<sole> argument.
793 Data::Dumper has now an option to sort hashes.
797 Data::Dumper has now an option to dump code references
802 The English module can now be used without the infamous performance
805 use English '-no_performance_hit';
807 (Assuming, of course, that one doesn't need the troublesome variables
808 C<$`>, C<$&>, or C<$'>.) Also, introduced C<@LAST_MATCH_START> and
809 C<@LAST_MATCH_END> English aliases for C<@-> and C<@+>.
813 Fcntl, Socket, and Sys::Syslog have been rewritten to use the
814 new-style constant dispatch section (see L<ExtUtils::Constant>).
815 This means that they will be more robust and hopefully faster.
819 File::Find now has pre- and post-processing callbacks. It also
820 correctly changes directories when chasing symbolic links. Callbacks
821 (naughtily) exiting with "next;" instead of "return;" now work.
825 File::Find is now (again) reentrant. It also has been made
830 File::Glob::glob() renamed to File::Glob::bsd_glob() to avoid
831 prototype mismatch with CORE::glob().
835 File::Glob now supports C<GLOB_LIMIT> constant to limit the size of
836 the returned list of filenames.
840 Devel::Peek now has an interface for the Perl memory statistics
841 (this works only if you are using perl's malloc, and if you have
842 compiled with debugging).
846 IPC::Open3 now allows the use of numeric file descriptors.
850 IO::Socket has now atmark() method, which returns true if the socket
851 is positioned at the out-of-band mark. The method is also exportable
852 as a sockatmark() function.
856 IO::Socket::INET has support for ReusePort option (if your platform
857 supports it). The Reuse option now has an alias, ReuseAddr. For clarity
858 you may want to prefer ReuseAddr.
862 IO::Socket::INET now supports C<LocalPort> of zero (usually meaning
863 that the operating system will make one up.)
867 use lib now works identically to @INC. Removing directories
868 with 'no lib' now works.
872 Math::BigFloat and Math::BigInt have undergone a full rewrite.
873 They are now magnitudes faster, and they support various
874 bignum libraries such as GMP and PARI as their backends.
878 Net::Ping has been enhanced. There is now "external" protocol which
879 uses Net::Ping::External module which runs external ping(1) and parses
880 the output. An alpha version of Net::Ping::External is available in
881 CPAN and in 5.7.2 the Net::Ping::External may be integrated to Perl.
885 C<POSIX::sigaction()> is now much more flexible and robust.
886 You can now install coderef handlers, 'DEFAULT', and 'IGNORE'
887 handlers, installing new handlers was not atomic.
891 C<%INC> now localised in a Safe compartment so that use/require work.
895 The Shell module now has an OO interface.
899 The Test module has been significantly enhanced.
903 The C<vars> pragma now supports declaring fully qualified variables.
904 (Something that C<our()> does not and will not support.)
908 The utf8:: name space (as in the pragma) provides various
909 Perl-callable functions to provide low level access to Perl's
910 internal Unicode representation. At the moment only length()
911 has been implemented.
915 =head1 Utility Changes
921 Emacs perl mode (emacs/cperl-mode.el) has been updated to version
926 F<emacs/e2ctags.pl> is now much faster.
930 C<h2ph> now supports C trigraphs.
934 C<h2xs> now produces a template README.
938 C<h2xs> now uses C<Devel::PPort> for better portability between
939 different versions of Perl.
943 C<h2xs> uses the new L<ExtUtils::Constant> module which will affect
944 newly created extensions that define constants. Since the new code is
945 more correct (if you have two constants where the first one is a
946 prefix of the second one, the first constant B<never> gets defined),
947 less lossy (it uses integers for integer constant, as opposed to the
948 old code that used floating point numbers even for integer constants),
949 and slightly faster, you might want to consider regenerating your
950 extension code (the new scheme makes regenerating easy).
951 L<h2xs> now also supports C trigraphs.
955 C<libnetcfg> has been added to configure the libnet.
959 C<perlbug> is now much more robust. It also sends the bug report to
960 perl.org, not perl.com.
964 C<perlcc> has been rewritten and its user interface (that is,
965 command line) is much more like that of the UNIX C compiler, cc.
969 C<perlivp> is a new utility for doing Installation Verification
970 Procedure after installing Perl.
974 C<pod2html> now allows specifying a cache directory.
978 C<s2p> has been completely rewritten in Perl. (It is in fact a full
979 implementation of sed in Perl: you can use the sed functionality by
980 using the C<psed> utility.)
984 C<xsubpp> now understands POD documentation embedded in the *.xs files.
988 C<xsubpp> now supports OUT keyword.
992 =head1 New Documentation
998 perl56delta details the changes between the 5.005 release and the
1003 perlclib documents the internal replacements for standard C library
1004 functions. (Interesting only for extension writers and Perl core
1009 perldebtut is a Perl debugging tutorial.
1013 perlebcdic contains considerations for running Perl on EBCDIC platforms.
1014 Note that unfortunately EBCDIC platforms that used to supported back in
1015 Perl 5.005 are still unsupported by Perl 5.7.0; the plan, however, is to
1016 bring them back to the fold.
1020 perlintro is a gentle introduction to Perl.
1024 perliol documents the internals of PerlIO with layers.
1028 perlmodstyle is a style guide for writing modules.
1032 perlnewmod tells about writing and submitting a new module.
1036 perlpod has been rewritten to be clearer and to record the best
1037 practices gathered over the years.
1041 perlpodstyle is a more formal specification of the pod format,
1042 mainly of interest for writers of pod applications, not to
1043 people writing in pod.
1047 perlposix-bc explains using Perl on the POSIX-BC platform
1048 (an EBCDIC mainframe platform).
1052 perlretut is a regular expression tutorial.
1056 perlrequick is a regular expressions quick-start guide.
1057 Yes, much quicker than perlretut.
1061 perltodo has been updated.
1065 perltootc has been renamed as perltooc (to not to conflict
1066 with perltoot in filesystems restricted to "8.3" names)
1070 perluniintro is an introduction to using Unicode in Perl
1071 (perlunicode is more of a reference)
1075 perlutil explains the command line utilities packaged with the Perl
1080 The following platform-specific documents are available before
1081 the installation as README.I<platform>, and after the installation
1084 perlaix perlamiga perlapollo perlbeos perlbs2000
1085 perlce perlcygwin perldgux perldos perlepoc perlhpux
1086 perlhurd perlmachten perlmacos perlmint perlmpeix
1087 perlnetware perlos2 perlos390 perlplan9 perlqnx perlsolaris
1088 perltru64 perluts perlvmesa perlvms perlvos perlwin32
1094 The documentation for the POSIX-BC platform is called "BS2000", to avoid
1095 confusion with the Perl POSIX module.
1099 The documentation for the WinCE platform is called "CE", to avoid
1100 confusion with the perlwin32 documentation on 8.3-restricted filesystems.
1104 =head1 Performance Enhancements
1110 map() that changes the size of the list should now work faster.
1114 sort() has been changed to use primarily mergesort internally as
1115 opposed to the earlier quicksort. For very small lists this may
1116 result in slightly slower sorting times, but in general the speedup
1117 should be at least 20%. Additional bonuses are that the worst case
1118 behaviour of sort() is now better (in computer science terms it now
1119 runs in time O(N log N), as opposed to quicksort's Theta(N**2)
1120 worst-case run time behaviour), and that sort() is now stable
1121 (meaning that elements with identical keys will stay ordered as they
1122 were before the sort). See the C<sort> pragma for information.
1126 Hashes now use Bob Jenkins "One-at-a-Time" hashing key algorithm
1127 (http://burtleburtle.net/bob/hash/doobs.html). This algorithm is
1128 reasonably fast while producing a much better spread of values than
1129 the old hashing algorithm (originally by Chris Torek, later tweaked by
1130 Ilya Zakharevich). Hash values output from the algorithm on a hash of
1131 all 3-char printable ASCII keys comes much closer to passing the
1132 DIEHARD random number generation tests. According to perlbench, this
1133 change has not affected the overall speed of Perl.
1137 unshift() should now be noticeably faster.
1141 =head1 Installation and Configuration Improvements
1143 =head2 Generic Improvements
1149 INSTALL now explains how you can configure Perl to use 64-bit
1150 integers even on non-64-bit platforms.
1154 Policy.sh policy change: if you are reusing a Policy.sh file
1155 (see INSTALL) and you use Configure -Dprefix=/foo/bar and in the old
1156 Policy $prefix eq $siteprefix and $prefix eq $vendorprefix, all of
1157 them will now be changed to the new prefix, /foo/bar. (Previously
1158 only $prefix changed.) If you do not like this new behaviour,
1159 specify prefix, siteprefix, and vendorprefix explicitly.
1163 A new optional location for Perl libraries, otherlibdirs, is available.
1164 It can be used for example for vendor add-ons without disturbing Perl's
1165 own library directories.
1169 In many platforms the vendor-supplied 'cc' is too stripped-down to
1170 build Perl (basically, 'cc' doesn't do ANSI C). If this seems
1171 to be the case and 'cc' does not seem to be the GNU C compiler
1172 'gcc', an automatic attempt is made to find and use 'gcc' instead.
1176 gcc needs to closely track the operating system release to avoid
1177 build problems. If Configure finds that gcc was built for a different
1178 operating system release than is running, it now gives a clearly visible
1179 warning that there may be trouble ahead.
1183 If binary compatibility with the 5.005 release is not wanted, Configure
1184 no longer suggests including the 5.005 modules in @INC.
1188 Configure C<-S> can now run non-interactively.
1192 configure.gnu now works with options with whitespace in them.
1196 installperl now outputs everything to STDERR.
1200 $Config{byteorder} is now computed dynamically (this is more robust
1201 with "fat binaries" where an executable image contains binaries for
1202 more than one binary platform.)
1206 Because PerlIO is now the default on most platforms, "-perlio" doesn't
1207 get appended to the $Config{archname} (also known as $^O) anymore.
1208 Instead, if you explicitly choose not to use perlio (Configure command
1209 line option -Uuseperlio), you will get "-stdio" appended.
1213 Another change related to the architecture name is that "-64all"
1214 (-Duse64bitall, or "maximally 64-bit") is appended only if your
1215 pointers are 64 bits wide. (To be exact, the use64bitall is ignored.)
1219 In AFS installations one can configure the root of the AFS to be
1220 somewhere else than the default F</afs> by using the Configure
1221 parameter C<-Dafsroot=/some/where/else>.
1225 APPLLIB_EXP, a less-know configuration-time definition, has been
1226 documented. It can be used to prepend site-specific directories
1227 to Perl's default search path (@INC), see INSTALL for information.
1231 The version of Berkeley DB used when the Perl (and, presumably, the
1232 DB_File extension) was built is now available as
1233 C<@Config{qw(db_version_major db_version_minor db_version_patch)}>
1234 from Perl and as C<DB_VERSION_MAJOR_CFG DB_VERSION_MINOR_CFG
1235 DB_VERSION_PATCH_CFG> from C.
1239 Building Berkeley DB3 for compatibility modes for DB, NDBM, and ODBM
1240 has been documented in INSTALL.
1244 If you have CPAN access (either network or a local copy such as a
1245 CD-ROM) you can during specify extra modules to Configure to build and
1246 install with Perl using the -Dextras=... option. See INSTALL for
1251 In addition to config.over a new override file, config.arch, is
1252 available. That is supposed to be used by hints file writers for
1253 architecture-wide changes (as opposed to config.over which is for
1258 If your file system supports symbolic links you can build Perl outside
1259 of the source directory by
1261 mkdir /tmp/perl/build/directory
1262 cd /tmp/perl/build/directory
1263 sh /path/to/perl/source/Configure -Dmksymlinks ...
1265 This will create in /tmp/perl/build/directory a tree of symbolic links
1266 pointing to files in /path/to/perl/source. The original files are left
1267 unaffected. After Configure has finished you can just say
1271 and Perl will be built and tested, all in /tmp/perl/build/directory.
1275 For Perl developers several new make targets for profiling
1276 and debugging have been added, see L<perlhack>.
1282 Use of the F<gprof> tool to profile Perl has been documented in
1283 L<perlhack>. There is a make target called "perl.gprof" for
1284 generating a gprofiled Perl executable.
1288 If you have GCC 3, there is a make target called "perl.gcov" for
1289 creating a gcoved Perl executable for coverage analysis. See
1294 If you are on IRIX or Tru64 platforms, new profiling/debugging options
1295 have been added, see L<perlhack> for more information about pixie and
1302 Guidelines of how to construct minimal Perl installations have
1303 been added to INSTALL.
1307 The Thread extension is now not built at all under ithreads
1308 (C<Configure -Duseithreads>) because it wouldn't work anyway (the
1309 Thread extension requires being Configured with C<-Duse5005threads>).
1311 But note that the Thread.pm interface is now shared by both
1316 =head2 New Or Improved Platforms
1318 For the list of platforms known to support Perl,
1319 see L<perlport/"Supported Platforms">.
1325 AIX dynamic loading should be now better supported.
1329 AIX should now work better with gcc, threads, and 64-bitness. Also the
1330 long doubles support in AIX should be better now. See L<perlaix>.
1334 After a long pause, AmigaOS has been verified to be happy with Perl.
1338 AtheOS (http://www.atheos.cx/) is a new platform.
1342 DG/UX platform now supports the 5.005-style threads. See L<perldgux>.
1346 DYNIX/ptx platform (a.k.a. dynixptx) is supported at or near osvers 4.5.2.
1350 EBCDIC platforms (z/OS, also known as OS/390, POSIX-BC, and VM/ESA)
1351 have been regained. Many test suite tests still fail and the
1352 co-existence of Unicode and EBCDIC isn't quite settled, but the
1353 situation is much better than with Perl 5.6. See L<perlos390>,
1354 L<perlbs2000> (for POSIX-BC), and L<perlvmesa> for more information.
1358 Building perl with -Duseithreads or -Duse5005threads now works under
1359 HP-UX 10.20 (previously it only worked under 10.30 or later). You will
1360 need a thread library package installed. See README.hpux.
1364 MacOS Classic (MacPerl has of course been available since
1365 perl 5.004 but now the source code bases of standard Perl
1366 and MacPerl have been synchronised)
1370 MacOS X (or Darwin) should now be able to build Perl even on HFS+
1371 filesystems. (The case-insensitivity confused the Perl build process.)
1375 NCR MP-RAS is now supported.
1379 NetWare from Novell is now supported. See L<perlnetware>.
1383 NonStop-UX is now supported.
1387 Amdahl UTS UNIX mainframe platform is now supported.
1391 WinCE is now supported. See L<perlce>.
1395 z/OS (formerly known as OS/390, formerly known as MVS OE) has now
1396 support for dynamic loading. This is not selected by default,
1397 however, you must specify -Dusedl in the arguments of Configure.
1401 =head1 Selected Bug Fixes
1403 Numerous memory leaks and uninitialized memory accesses have been
1404 hunted down. Most importantly anonymous subs used to leak quite
1411 The autouse pragma didn't work for Multi::Part::Function::Names.
1415 chop(@list) in list context returned the characters chopped in
1416 reverse order. This has been reversed to be in the right order.
1420 Configure no longer includes the DBM libraries (dbm, gdbm, db, ndbm)
1421 when building the Perl binary. The only exception to this is SunOS 4.x,
1426 The behaviour of non-decimal but numeric string constants such as
1427 "0x23" was platform-dependent: in some platforms that was seen as 35,
1428 in some as 0, in some as a floating point number (don't ask). This
1429 was caused by Perl using the operating system libraries in a situation
1430 where the result of the string to number conversion is undefined: now
1431 Perl consistently handles such strings as zero in numeric contexts.
1435 The order of DESTROYs has been made more predictable.
1439 Several debugger fixes: exit code now reflects the script exit code,
1440 condition C<"0"> now treated correctly, the C<d> command now checks
1441 line number, the C<$.> no longer gets corrupted, all debugger output now
1442 goes correctly to the socket if RemotePort is set.
1446 L<dprofpp> -R didn't work.
1450 C<*foo{FORMAT}> now works.
1454 UNIVERSAL::isa no longer caches methods incorrectly. (This broke
1455 the Tk extension with 5.6.0.)
1459 Lexicals I: lexicals outside an eval "" weren't resolved
1460 correctly inside a subroutine definition inside the eval "" if they
1461 were not already referenced in the top level of the eval""ed code.
1465 Lexicals II: lexicals leaked at file scope into subroutines that
1466 were declared before the lexicals.
1470 Lexical warnings now propagating correctly between scopes.
1474 Line renumbering with eval and C<#line> now works.
1478 Fixed numerous memory leaks, especially in eval "".
1482 mkdir() now ignores trailing slashes in the directory name,
1483 as mandated by POSIX.
1487 Some versions of glibc have a broken modfl(). This affects builds
1488 with C<-Duselongdouble>. This version of Perl detects this brokenness
1489 and has a workaround for it. The glibc release 2.2.2 is known to have
1490 fixed the modfl() bug.
1494 Modulus of unsigned numbers now works (4063328477 % 65535 used to
1495 return 27406, instead of 27047).
1499 Some "not a number" warnings introduced in 5.6.0 eliminated to be
1500 more compatible with 5.005. Infinity is now recognised as a number.
1504 Attributes (like :shared) didn't work with our().
1508 our() variables will not cause "will not stay shared" warnings.
1512 pack "Z" now correctly terminates the string with "\0".
1516 Fix password routines which in some shadow password platforms
1517 (e.g. HP-UX) caused getpwent() to return every other entry.
1521 The PERL5OPT environment variable (for passing command line arguments
1522 to Perl) didn't work for more than a single group of options.
1526 PERL5OPT with embedded spaces didn't work.
1530 printf() no longer resets the numeric locale to "C".
1534 C<q(a\\b)> now parses correctly as C<'a\\b'>.
1538 Printing quads (64-bit integers) with printf/sprintf now works
1539 without the q L ll prefixes (assuming you are on a quad-capable platform).
1543 Regular expressions on references and overloaded scalars now work.
1547 Right-hand side magic (GMAGIC) could in many cases such as string
1548 concatenation be invoked too many times.
1552 scalar() now forces scalar context even when used in void context.
1556 SOCKS support is now much more robust.
1560 sort() arguments are now compiled in the right wantarray context
1561 (they were accidentally using the context of the sort() itself).
1565 Changed the POSIX character class C<[[:space:]]> to include the (very
1566 rarely used) vertical tab character. Added a new POSIX-ish character
1567 class C<[[:blank:]]> which stands for horizontal whitespace
1568 (currently, the space and the tab).
1572 The tainting behaviour of sprintf() has been rationalized. It does
1573 not taint the result of floating point formats anymore, making the
1574 behaviour consistent with that of string interpolation.
1578 The regular expression captured submatches ($1, $2, ...) are now
1579 more consistently unset if the match fails, instead of leaving false
1580 data lying around in them.
1584 C<Sys::Syslog> ignored the C<LOG_AUTH> constant.
1588 All but the first argument of the IO syswrite() method are now optional.
1592 $AUTOLOAD, sort(), lock(), and spawning subprocesses
1593 in multiple threads simultaneously are now thread-safe.
1597 Tie::ARRAY SPLICE method was broken.
1601 Allow read-only string on left hand side of non-modifying tr///.
1605 Several Unicode fixes.
1611 BOMs (byte order marks) in the beginning of Perl files
1612 (scripts, modules) should now be transparently skipped.
1613 UTF-16 (UCS-2) encoded Perl files should now be read correctly.
1617 The character tables have been updated to Unicode 3.1.1.
1621 Comparing with utf8 data does not magically upgrade non-utf8 data
1626 C<IsAlnum>, C<IsAlpha>, and C<IsWord> now match titlecase.
1630 Concatenation with the C<.> operator or via variable interpolation,
1631 C<eq>, C<substr>, C<reverse>, C<quotemeta>, the C<x> operator,
1632 substitution with C<s///>, single-quoted UTF8, should now work.
1636 The C<tr///> operator now works. Note that the C<tr///CU>
1637 functionality has been removed (but see pack('U0', ...)).
1641 C<eval "v200"> now works.
1645 Zero entries were missing from the Unicode classes like C<IsDigit>.
1651 =head2 Platform Specific Changes and Fixes
1659 Perl now works on post-4.0 BSD/OSes.
1665 Setting C<$0> now works (as much as possible; see perlvar for details).
1671 Numerous updates; currently synchronised with Cygwin 1.1.4.
1675 Previously DYNIX/ptx had problems in its Configure probe for non-blocking I/O.
1681 EPOC update after Perl 5.6.0. See README.epoc.
1687 Perl now works on post-3.0 FreeBSDs.
1693 README.hpux updated; C<Configure -Duse64bitall> now almost works.
1699 Numerous compilation flag and hint enhancements; accidental mixing
1700 of 32-bit and 64-bit libraries (a doomed attempt) made much harder.
1710 Long doubles should now work (see INSTALL).
1714 Linux previously had problems related to sockaddrlen when using
1715 accept(), revcfrom() (in Perl: recv()), getpeername(), and getsockname().
1723 Compilation of the standard Perl distribution in MacOS Classic should
1724 now work if you have the Metrowerks development environment and
1725 the missing Mac-specific toolkit bits. Contact the macperl mailing
1732 MPE/iX update after Perl 5.6.0. See README.mpeix.
1738 Perl now works on NetBSD/sparc.
1744 Now works with usethreads (see INSTALL).
1750 64-bitness using the Sun Workshop compiler now works.
1754 Tru64 (aka Digital UNIX, aka DEC OSF/1)
1756 The operating system version letter now recorded in $Config{osvers}.
1757 Allow compiling with gcc (previously explicitly forbidden). Compiling
1758 with gcc still not recommended because buggy code results, even with
1765 Fixed various alignment problems that lead into core dumps either
1766 during build or later; no longer dies on math errors at runtime;
1767 now using full quad integers (64 bits), previously was using
1768 only 46 bit integers for speed.
1774 chdir() now works better despite a CRT bug; now works with MULTIPLICITY
1775 (see INSTALL); now works with Perl's malloc.
1785 accept() no longer leaks memory.
1789 Borland C++ v5.5 is now a supported compiler that can build Perl.
1790 However, the generated binaries continue to be incompatible with those
1791 generated by the other supported compilers (GCC and Visual C++).
1795 Better chdir() return value for a non-existent directory.
1799 Duping socket handles with open(F, ">&MYSOCK") now works under Windows 9x.
1803 New %ENV entries now propagate to subprocesses.
1807 $ENV{LIB} now used to search for libs under Visual C.
1811 Win32::GetCwd() correctly returns C:\ instead of C: when at the drive root.
1812 Other bugs in chdir() and Cwd::cwd() have also been fixed.
1816 A failed (pseudo)fork now returns undef and sets errno to EAGAIN.
1820 HTML files will be installed in c:\perl\html instead of c:\perl\lib\pod\html
1824 The makefiles now provide a single switch to bulk-enable all the features
1825 enabled in ActiveState ActivePerl (a popular Win32 binary distribution).
1829 Allow REG_EXPAND_SZ keys in the registry.
1833 Can now send() from all threads, not just the first one.
1837 Fake signal handling reenabled, bugs and all.
1841 Less stack reserved per thread so that more threads can run
1842 concurrently. (Still 16M per thread.)
1846 C<File::Spec->tmpdir()> now prefers C:/temp over /tmp
1847 (works better when perl is running as service).
1851 Better UNC path handling under ithreads.
1855 wait() and waitpid() now work much better.
1859 winsock handle leak fixed.
1865 =head1 New or Changed Diagnostics
1871 All regular expression compilation error messages are now hopefully
1872 easier to understand both because the error message now comes before
1873 the failed regex and because the point of failure is now clearly
1874 marked by a C<E<lt>-- HERE> marker.
1878 The various "opened only for", "on closed", "never opened" warnings
1879 drop the C<main::> prefix for filehandles in the C<main> package,
1880 for example C<STDIN> instead of C<main::STDIN>.
1884 The "Unrecognized escape" warning has been extended to include C<\8>,
1885 C<\9>, and C<\_>. There is no need to escape any of the C<\w> characters.
1889 Two new debugging options have been added: if you have compiled your
1890 Perl with debugging, you can use the -DT and -DR options to trace
1891 tokenising and to add reference counts to displaying variables,
1896 If an attempt to use a (non-blessed) reference as an array index
1897 is made, a warning is given.
1901 C<push @a;> and C<unshift @a;> (with no values to push or unshift)
1902 now give a warning. This may be a problem for generated and evaled
1907 If you try to L<perlfunc/pack> a number less than 0 or larger than 255
1908 using the C<"C"> format you will get an optional warning. Similarly
1909 for the C<"c"> format and a number less than -128 or more than 127.
1913 Certain regex modifiers such as C<(?o)> make sense only if applied to
1914 the entire regex. You will an optional warning if you try to do otherwise.
1918 Using arrays or hashes as references (e.g. C<< %foo->{bar} >>
1919 has been deprecated for a while. Now you will get an optional warning.
1923 =head1 Changed Internals
1929 perlapi.pod (a companion to perlguts) now attempts to document the
1934 You can now build a really minimal perl called microperl.
1935 Building microperl does not require even running Configure;
1936 C<make -f Makefile.micro> should be enough. Beware: microperl makes
1937 many assumptions, some of which may be too bold; the resulting
1938 executable may crash or otherwise misbehave in wondrous ways.
1939 For careful hackers only.
1943 Added rsignal(), whichsig(), do_join(), op_clear, op_null,
1944 ptr_table_clear(), ptr_table_free(), sv_setref_uv(), and several UTF-8
1945 interfaces to the publicised API. For the full list of the available
1946 APIs see L<perlapi>.
1950 Made possible to propagate customised exceptions via croak()ing.
1954 Now xsubs can have attributes just like subs.
1958 dTHR and djSP have been obsoleted; the former removed (because it's
1959 a no-op) and the latter replaced with dSP.
1963 PERL_OBJECT has been completely removed.
1967 The MAGIC constants (e.g. C<'P'>) have been macrofied
1968 (e.g. C<PERL_MAGIC_TIED>) for better source code readability
1969 and maintainability.
1973 The regex compiler now maintains a structure that identifies nodes in
1974 the compiled bytecode with the corresponding syntactic features of the
1975 original regex expression. The information is attached to the new
1976 C<offsets> member of the C<struct regexp>. See L<perldebguts> for more
1977 complete information.
1981 The C code has been made much more C<gcc -Wall> clean. Some warning
1982 messages still remain in some platforms, so if you are compiling with
1983 gcc you may see some warnings about dubious practices. The warnings
1984 are being worked on.
1988 F<perly.c>, F<sv.c>, and F<sv.h> have now been extensively commented.
1992 Documentation on how to use the Perl source repository has been added
1993 to F<Porting/repository.pod>.
1997 There are now several profiling make targets.
2001 =head1 Security Vulnerability Closed
2003 (This change was already made in 5.7.0 but bears repeating here.)
2005 A potential security vulnerability in the optional suidperl component
2006 of Perl was identified in August 2000. suidperl is neither built nor
2007 installed by default. As of November 2001 the only known vulnerable
2008 platform is Linux, most likely all Linux distributions. CERT and
2009 various vendors and distributors have been alerted about the vulnerability.
2010 See http://www.cpan.org/src/5.0/sperl-2000-08-05/sperl-2000-08-05.txt
2011 for more information.
2013 The problem was caused by Perl trying to report a suspected security
2014 exploit attempt using an external program, /bin/mail. On Linux
2015 platforms the /bin/mail program had an undocumented feature which
2016 when combined with suidperl gave access to a root shell, resulting in
2017 a serious compromise instead of reporting the exploit attempt. If you
2018 don't have /bin/mail, or if you have 'safe setuid scripts', or if
2019 suidperl is not installed, you are safe.
2021 The exploit attempt reporting feature has been completely removed from
2022 Perl 5.8.0 (and the maintenance release 5.6.1, and it was removed also
2023 from all the Perl 5.7 releases), so that particular vulnerability
2024 isn't there anymore. However, further security vulnerabilities are,
2025 unfortunately, always possible. The suidperl functionality is most
2026 probably going to be removed in Perl 5.10. In any case, suidperl
2027 should only be used by security experts who know exactly what they are
2028 doing and why they are using suidperl instead of some other solution
2029 such as sudo (see http://www.courtesan.com/sudo/).
2033 Several new tests have been added, especially for the F<lib> subsection.
2035 The tests are now reported in a different order than in earlier Perls.
2036 (This happens because the test scripts from under t/lib have been moved
2037 to be closer to the library/extension they are testing.)
2039 =head1 Known Problems
2041 Note that unlike other sections in this document (which describe
2042 changes since 5.7.0) this section is cumulative containing known
2043 problems for all the 5.7 releases.
2051 In AIX 4.2 Perl extensions that use C++ functions that use statics
2052 may have problems in that the statics are not getting initialized.
2053 In newer AIX releases this has been solved by linking Perl with
2054 the libC_r library, but unfortunately in AIX 4.2 the said library
2055 has an obscure bug where the various functions related to time
2056 (such as time() and gettimeofday()) return broken values, and
2057 therefore in AIX 4.2 Perl is not linked against the libC_r.
2061 vac 5.0.0.0 May Produce Buggy Code For Perl
2063 The AIX C compiler vac version 5.0.0.0 may produce buggy code,
2064 resulting in few random tests failing, but when the failing tests
2065 are run by hand, they succeed. We suggest upgrading to at least
2066 vac version 5.0.1.0, that has been known to compile Perl correctly.
2067 "lslpp -L|grep vac.C" will tell you the vac version.
2071 =head2 Amiga Perl Invoking Mystery
2073 One cannot call Perl using the C<volume:> syntax, that is, C<perl -v>
2074 works, but for example C<bin:perl -v> doesn't. The exact reason is
2075 known but the current suspect is the F<ixemul> library.
2077 =head2 lib/ftmp-security tests warn 'system possibly insecure'
2079 Don't panic. Read INSTALL 'make test' section instead.
2081 =head2 Cygwin intermittent failures of lib/Memoize/t/expire_file 11 and 12
2083 The subtests 11 and 12 sometimes fail and sometimes work.
2085 =head2 HP-UX lib/io_multihomed Fails When LP64-Configured
2087 The lib/io_multihomed test may hang in HP-UX if Perl has been
2088 configured to be 64-bit. Because other 64-bit platforms do not hang in
2089 this test, HP-UX is suspect. All other tests pass in 64-bit HP-UX. The
2090 test attempts to create and connect to "multihomed" sockets (sockets
2091 which have multiple IP addresses).
2093 =head2 HP-UX lib/posix Subtest 9 Fails When LP64-Configured
2095 If perl is configured with -Duse64bitall, the successful result of the
2096 subtest 10 of lib/posix may arrive before the successful result of the
2097 subtest 9, which confuses the test harness so much that it thinks the
2100 =head2 Linux With Sfio Fails op/misc Test 48
2106 OS/390 has rather many test failures but the situation is actually
2107 better than it was in 5.6.0, it's just that so many new modules and
2108 tests have been added.
2110 Failed Test Stat Wstat Total Fail Failed List of Failed
2111 -----------------------------------------------------------------------------
2112 ../ext/B/Deparse.t 14 1 7.14% 14
2113 ../ext/B/Showlex.t 1 1 100.00% 1
2114 ../ext/Encode/Encode/Tcl.t 610 13 2.13% 592 594 596 598
2116 ../ext/IO/lib/IO/t/io_unix.t 113 28928 5 3 60.00% 3-5
2117 ../ext/POSIX/POSIX.t 29 1 3.45% 14
2118 ../ext/Storable/t/lock.t 255 65280 5 3 60.00% 3-5
2119 ../lib/locale.t 129 33024 117 19 16.24% 99-117
2120 ../lib/warnings.t 434 1 0.23% 75
2121 ../lib/ExtUtils.t 27 1 3.70% 25
2122 ../lib/Math/BigInt/t/bigintpm.t 1190 1 0.08% 1145
2123 ../lib/Unicode/UCD.t 81 48 59.26% 1-16 49-64 66-81
2124 ../lib/User/pwent.t 9 1 11.11% 4
2125 op/pat.t 660 6 0.91% 242-243 424-425
2127 op/split.t 0 9 ?? ?? % ??
2128 op/taint.t 174 3 1.72% 156 162 168
2129 op/tr.t 70 3 4.29% 50 58-59
2130 Failed 16/422 test scripts, 96.21% okay. 105/23251 subtests failed, 99.55% okay.
2132 =head2 op/sprintf tests 129 and 130
2134 The op/sprintf tests 129 and 130 are known to fail on some platforms.
2135 Examples include any platform using sfio, and Compaq/Tandem's NonStop-UX.
2136 The failing platforms do not comply with the ANSI C Standard, line
2137 19ff on page 134 of ANSI X3.159 1989 to be exact. (They produce
2138 something other than "1" and "-1" when formatting 0.6 and -0.6 using
2139 the printf format "%.0f", most often they produce "0" and "-0".)
2141 =head2 Failure of Thread tests
2143 B<Note that support for 5.005-style threading remains experimental.>
2145 The following tests are known to fail due to fundamental problems in
2146 the 5.005 threading implementation. These are not new failures--Perl
2147 5.005_0x has the same bugs, but didn't have these tests.
2150 t/lib/thr5005.t 19-20
2158 ext/POSIX/sigaction subtests 6 and 13 may fail.
2162 lib/ExtUtils may spuriously claim that subtest 28 failed,
2163 which is interesting since the test only has 27 tests.
2167 Numerous numerical test failures
2169 op/numconvert 209,210,217,218
2171 ext/Time/HiRes/HiRes 9
2172 lib/Math/BigInt/t/bigintpm 1145
2175 These tests fail because of yet unresolved floating point inaccuracies.
2181 There are a few known test failures, see L<perluts>.
2185 Rather many tests are failing in VMS but that actually more tests
2186 succeed in VMS than they used to, it's just that there are many,
2187 many more tests than there used to be.
2189 Here are the known failures from some compiler/platform combinations.
2191 DEC C V5.3-006 on OpenVMS VAX V6.2
2193 [-.ext.list.util.t]tainted..............FAILED on test 3
2194 [-.ext.posix]sigaction..................FAILED on test 7
2195 [-.ext.time.hires]hires.................FAILED on test 14
2196 [-.lib.file.find]taint..................FAILED on test 17
2197 [-.lib.math.bigint.t]bigintpm...........FAILED on test 1183
2198 [-.lib.test.simple.t]exit...............FAILED on test 1
2199 [.lib]vmsish............................FAILED on test 13
2200 [.op]sprintf............................FAILED on test 12
2201 Failed 8/399 tests, 91.23% okay.
2203 DEC C V6.0-001 on OpenVMS Alpha V7.2-1 and
2204 Compaq C V6.2-008 on OpenVMS Alpha V7.1
2206 [-.ext.list.util.t]tainted..............FAILED on test 3
2207 [-.lib.file.find]taint..................FAILED on test 17
2208 [-.lib.test.simple.t]exit...............FAILED on test 1
2209 [.lib]vmsish............................FAILED on test 13
2210 Failed 4/399 tests, 92.48% okay.
2212 Compaq C V6.4-005 on OpenVMS Alpha 7.2.1
2214 [-.ext.b]showlex........................FAILED on test 1
2215 [-.ext.list.util.t]tainted..............FAILED on test 3
2216 [-.lib.file.find]taint..................FAILED on test 17
2217 [-.lib.test.simple.t]exit...............FAILED on test 1
2218 [.lib]vmsish............................FAILED on test 13
2219 [.op]misc...............................FAILED on test 49
2220 Failed 6/401 tests, 92.77% okay.
2224 In multi-CPU boxes there are some problems with the I/O buffering:
2225 some output may appear twice.
2227 =head2 Localising a Tied Variable Leaks Memory
2230 tie my %tie_hash => 'Tie::StdHash';
2234 local($tie_hash{Foo}) = 1; # leaks
2236 Code like the above is known to leak memory every time the local()
2239 =head2 Self-tying of Arrays and Hashes Is Forbidden
2241 Self-tying of arrays and hashes is broken in rather deep and
2242 hard-to-fix ways. As a stop-gap measure to avoid people from getting
2243 frustrated at the mysterious results (core dumps, most often) it is
2244 for now forbidden (you will get a fatal error even from an attempt).
2246 =head2 Variable Attributes are not Currently Usable for Tieing
2248 This limitation will hopefully be fixed in future. (Subroutine
2249 attributes work fine for tieing, see L<Attribute::Handlers>).
2251 =head2 Building Extensions Can Fail Because Of Largefiles
2253 Some extensions like mod_perl are known to have issues with
2254 `largefiles', a change brought by Perl 5.6.0 in which file offsets
2255 default to 64 bits wide, where supported. Modules may fail to compile
2256 at all or compile and work incorrectly. Currently there is no good
2257 solution for the problem, but Configure now provides appropriate
2258 non-largefile ccflags, ldflags, libswanted, and libs in the %Config
2259 hash (e.g., $Config{ccflags_nolargefiles}) so the extensions that are
2260 having problems can try configuring themselves without the
2261 largefileness. This is admittedly not a clean solution, and the
2262 solution may not even work at all. One potential failure is whether
2263 one can (or, if one can, whether it's a good idea) link together at
2264 all binaries with different ideas about file offsets, all this is
2267 =head2 The Compiler Suite Is Still Experimental
2269 The compiler suite is slowly getting better but is nowhere near
2272 =head2 The Long Double Support is Still Experimental
2274 The ability to configure Perl's numbers to use "long doubles",
2275 floating point numbers of hopefully better accuracy, is still
2276 experimental. The implementations of long doubles are not yet
2277 widespread and the existing implementations are not quite mature
2278 or standardised, therefore trying to support them is a rare
2279 and moving target. The gain of more precision may also be offset
2280 by slowdown in computations (more bits to move around, and the
2281 operations are more likely to be executed by less optimised
2284 =head1 Reporting Bugs
2286 If you find what you think is a bug, you might check the articles
2287 recently posted to the comp.lang.perl.misc newsgroup and the perl
2288 bug database at http://bugs.perl.org. There may also be
2289 information at http://www.perl.com/perl/, the Perl Home Page.
2291 If you believe you have an unreported bug, please run the B<perlbug>
2292 program included with your release. Be sure to trim your bug down
2293 to a tiny but sufficient test case. Your bug report, along with the
2294 output of C<perl -V>, will be sent off to perlbug@perl.org to be
2295 analysed by the Perl porting team.
2299 The F<Changes> file for exhaustive details on what changed.
2301 The F<INSTALL> file for how to build Perl.
2303 The F<README> file for general stuff.
2305 The F<Artistic> and F<Copying> files for copyright information.
2309 Written by Jarkko Hietaniemi <F<jhi@iki.fi>>.