3 perldelta - what is new for perl v5.8.0
7 This document describes differences between the 5.6.0 release and
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
12 coordinated (while 5.8.0 was still called 5.7.something).
14 Changes that were integrated into the 5.6.1 release are marked C<[561]>.
15 Many of these changes have been further developed since 5.6.1 was released,
16 those are marked C<[561+]>.
18 You can see the list of changes in the 5.6.1 release (both from the
19 5.005_03 release and the 5.6.0 release) by reading L<perl561delta>.
21 =head1 Highlights In 5.8.0
27 Better Unicode support
35 New Thread Implementation
39 Better Numeric Accuracy
51 More Extensive Regression Testing
55 =head1 Incompatible Changes
57 =head2 Binary Incompatibility
59 B<Perl 5.8 is not binary compatible with earlier releases of Perl.>
61 B<You have to recompile your XS modules.>
63 (Pure Perl modules should continue to work.)
65 The major reason for the discontinuity is the new IO architecture
66 called PerlIO. PerlIO is the default configuration because without
67 it many new features of Perl 5.8 cannot be used. In other words:
68 you just have to recompile your modules containing XS code, sorry
71 In future releases of Perl, non-PerlIO aware XS modules may become
72 completely unsupported. This shouldn't be too difficult for module
73 authors, however: PerlIO has been designed as a drop-in replacement
74 (at the source code level) for the stdio interface.
76 Depending on your platform, there are also other reasons why
77 we decided to break binary compatibility, please read on.
79 =head2 64-bit platforms and malloc
81 If your pointers are 64 bits wide, the Perl malloc is no longer being
82 used because it does not work well with 8-byte pointers. Also,
83 usually the system mallocs on such platforms are much better optimized
84 for such large memory models than the Perl malloc. Some memory-hungry
85 Perl applications like the PDL don't work well with Perl's malloc.
86 Finally, other applications than Perl (such as mod_perl) tend to prefer
87 the system malloc. Such platforms include Alpha and 64-bit HPPA,
90 =head2 AIX Dynaloading
92 The AIX dynaloading now uses in AIX releases 4.3 and newer the native
93 dlopen interface of AIX instead of the old emulated interface. This
94 change will probably break backward compatibility with compiled
95 modules. The change was made to make Perl more compliant with other
96 applications like mod_perl which are using the AIX native interface.
98 =head2 Attributes for C<my> variables now handled at run-time.
100 The C<my EXPR : ATTRS> syntax now applies variable attributes at
101 run-time. (Subroutine and C<our> variables still get attributes applied
102 at compile-time.) See L<attributes> for additional details. In particular,
103 however, this allows variable attributes to be useful for C<tie> interfaces,
104 which was a deficiency of earlier releases. Note that the new semantics
105 doesn't work with the Attribute::Handlers module (as of version 0.76).
107 =head2 Socket Extension Dynamic in VMS
109 The Socket extension is now dynamically loaded instead of being
110 statically built in. This may or may not be a problem with ancient
111 TCP/IP stacks of VMS: we do not know since we weren't able to test
112 Perl in such configurations.
114 =head2 IEEE-format Floating Point Default on OpenVMS Alpha
116 Perl now uses IEEE format (T_FLOAT) as the default internal floating
117 point format on OpenVMS Alpha, potentially breaking binary compatibility
118 with external libraries or existing data. G_FLOAT is still available as
119 a configuration option. The default on VAX (D_FLOAT) has not changed.
121 =head2 New Unicode Properties
123 Unicode I<scripts> are now supported. Scripts are similar to (and superior
124 to) Unicode I<blocks>. The difference between scripts and blocks is that
125 scripts are the glyphs used by a language or a group of languages, while
126 the blocks are more artificial groupings of (mostly) 256 characters based
127 on the Unicode numbering.
129 In general, scripts are more inclusive, but not universally so. For
130 example, while the script C<Latin> includes all the Latin characters and
131 their various diacritic-adorned versions, it does not include the various
132 punctuation or digits (since they are not solely C<Latin>).
134 A number of other properties are now supported, including C<\p{L&}>,
135 C<\p{Any}> C<\p{Assigned}>, C<\p{Unassigned}>, C<\p{Blank}> [561] and
136 C<\p{SpacePerl}> [561] (along with their C<\P{...}> versions, of course).
137 See L<perlunicode> for details, and more additions.
139 The C<In> or C<Is> prefix to names used with the C<\p{...}> and C<\P{...}>
140 are now almost always optional. The only exception is that a C<In> prefix
141 is required to signify a Unicode block when a block name conflicts with a
142 script name. For example, C<\p{Tibetan}> refers to the script, while
143 C<\p{InTibetan}> refers to the block. When there is no name conflict, you
144 can omit the C<In> from the block name (e.g. C<\p{BraillePatterns}>), but
145 to be safe, it's probably best to always use the C<In>).
147 =head2 REF(...) Instead Of SCALAR(...)
149 A reference to a reference now stringifies as "REF(0x81485ec)" instead
150 of "SCALAR(0x81485ec)" in order to be more consistent with the return
153 =head2 pack/unpack D/F recycled
155 The undocumented pack/unpack template letters D/F have been recycled
156 for better use: now they stand for long double (if supported by the
157 platform) and NV (Perl internal floating point type). (They used
158 to be aliases for d/f, but you never knew that.)
166 The semantics of bless(REF, REF) were unclear and until someone proves
167 it to make some sense, it is forbidden.
171 The obsolete chat2 library that should never have been allowed
172 to escape the laboratory has been decommissioned.
176 The builtin dump() function has probably outlived most of its
177 usefulness. The core-dumping functionality will remain in future
178 available as an explicit call to C<CORE::dump()>, but in future
179 releases the behaviour of an unqualified C<dump()> call may change.
183 The very dusty examples in the eg/ directory have been removed.
184 Suggestions for new shiny examples welcome but the main issue is that
185 the examples need to be documented, tested and (most importantly)
190 The (bogus) escape sequences \8 and \9 now give an optional warning
191 ("Unrecognized escape passed through"). There is no need to \-escape
196 The list of filenames from glob() (or <...>) is now by default sorted
197 alphabetically to be csh-compliant (which is what happened before
198 in most UNIX platforms). (bsd_glob() does still sort platform
199 natively, ASCII or EBCDIC, unless GLOB_ALPHASORT is specified.) [561]
203 Spurious syntax errors generated in certain situations, when glob()
204 caused File::Glob to be loaded for the first time, have been fixed. [561]
208 Although "you shouldn't do that", it was possible to write code that
209 depends on Perl's hashed key order (Data::Dumper does this). The new
210 algorithm "One-at-a-Time" produces a different hashed key order.
211 More details are in L</"Performance Enhancements">.
215 lstat(FILEHANDLE) now gives a warning because the operation makes no sense.
216 In future releases this may become a fatal error.
220 The C<package;> syntax (C<package> without an argument) has been
221 deprecated. Its semantics were never that clear and its
222 implementation even less so. If you have used that feature to
223 disallow all but fully qualified variables, C<use strict;> instead.
227 The unimplemented POSIX regex features [[.cc.]] and [[=c=]] are still
228 recognised but now cause fatal errors. The previous behaviour of
229 ignoring them by default and warning if requested was unacceptable
230 since it, in a way, falsely promised that the features could be used.
234 In future releases, non-PerlIO aware XS modules may become completely
235 unsupported. Since PerlIO is a drop-in replacement for stdio at the
236 source code level, this shouldn't be that drastic a change.
240 Previous versions of perl and some readings of some sections of Camel III
241 implied that the C<:raw> "discipline" was the inverse of C<:crlf>.
242 Turning off "clrfness" is no longer enough to make a stream truly
243 binary. So the PerlIO C<:raw> layer (or "discipline", to use the
244 Camel book's older terminology) is now formally defined as being
245 equivalent to binmode(FH) - which is in turn defined as doing whatever
246 is necessary to pass each byte as-is without any translation.
247 In particular binmode(FH) - and hence C<:raw> - will now turn off both CRLF
248 and UTF-8 translation and remove other layers (e.g. :encoding()) which
249 would modify byte stream.
253 The current user-visible implementation of pseudo-hashes (the weird
254 use of the first array element) is deprecated starting from Perl 5.8.0
255 and will be removed in Perl 5.10.0, and the feature will be
256 implemented differently. Not only is the current interface rather
257 ugly, but the current implementation slows down normal array and hash
258 use quite noticeably. The C<fields> pragma interface will remain
259 available. The I<restricted hashes> interface is expected to
260 be the replacement interface (see L<Hash::Util>). If your existing
261 programs depends on the underlying implementation, consider using
262 L<Class::PseudoHash> from CPAN.
266 The syntaxes C<< @a->[...] >> and C<< %h->{...} >> have now been deprecated.
270 After years of trying, suidperl is considered to be too complex to
271 ever be considered truly secure. The suidperl functionality is likely
272 to be removed in a future release.
276 The 5.005 threads model (module C<Thread>) is deprecated and expected
277 to be removed in Perl 5.10. Multithreaded code should be migrated to
278 the new ithreads model (see L<threads>, L<threads::shared> and
283 The long deprecated uppercase aliases for the string comparison
284 operators (EQ, NE, LT, LE, GE, GT) have now been removed.
288 The tr///C and tr///U features have been removed and will not return;
289 the interface was a mistake. Sorry about that. For similar
290 functionality, see pack('U0', ...) and pack('C0', ...). [561]
294 Earlier Perls treated "sub foo (@bar)" as equivalent to "sub foo (@)".
295 The prototypes are now checked better at compile-time for invalid
296 syntax. An optional warning is generated ("Illegal character in
297 prototype...") but this may be upgraded to a fatal error in a future
302 The C<exec LIST> and C<system LIST> operations will produce fatal
303 errors on tainted data in some future release.
307 The existing behaviour when localising tied arrays and hashes is wrong,
308 and will be changed in a future release, so do not rely on the existing
309 behaviour. See L<"Localising Tied Arrays and Hashes Is Broken">.
313 =head1 Core Enhancements
315 =head2 PerlIO is Now The Default
321 IO is now by default done via PerlIO rather than system's "stdio".
322 PerlIO allows "layers" to be "pushed" onto a file handle to alter the
323 handle's behaviour. Layers can be specified at open time via 3-arg
326 open($fh,'>:crlf :utf8', $path) || ...
328 or on already opened handles via extended C<binmode>:
330 binmode($fh,':encoding(iso-8859-7)');
332 The built-in layers are: unix (low level read/write), stdio (as in
333 previous Perls), perlio (re-implementation of stdio buffering in a
334 portable manner), crlf (does CRLF <=> "\n" translation as on Win32,
335 but available on any platform). A mmap layer may be available if
336 platform supports it (mostly UNIXes).
338 Layers to be applied by default may be specified via the 'open' pragma.
340 See L</"Installation and Configuration Improvements"> for the effects
341 of PerlIO on your architecture name.
345 If your platform supports fork(), you can use the list form of C<open>
346 for pipes. For example:
348 open KID_PS, "-|", "ps", "aux" or die $!;
350 forks the ps(1) command (without spawning a shell, as there are more
351 than three arguments to open()), and reads its standard output via the
352 C<KID_PS> filehandle. See L<perlipc>.
356 File handles can be marked as accepting Perl's internal encoding of Unicode
357 (UTF-8 or UTF-EBCDIC depending on platform) by a pseudo layer ":utf8" :
359 open($fh,">:utf8","Uni.txt");
361 Note for EBCDIC users: the pseudo layer ":utf8" is erroneously named
362 for you since it's not UTF-8 what you will be getting but instead
363 UTF-EBCDIC. See L<perlunicode>, L<utf8>, and
364 http://www.unicode.org/unicode/reports/tr16/ for more information.
365 In future releases this naming may change. See L<perluniintro>
366 for more information about UTF-8.
370 If your environment variables (LC_ALL, LC_CTYPE, LANG, LANGUAGE) look
371 like you want to use UTF-8 (any of the the variables match C</utf-?8/i>),
372 your STDIN, STDOUT, STDERR handles and the default open layer
373 (see L<open>) are marked as UTF-8. (This feature, like other new
374 features that combine Unicode and I/O, work only if you are using
375 PerlIO, but that's is the default.)
377 Note that after this Perl really does assume that everything is UTF-8:
378 for example if some input handle is not, Perl will probably very soon
379 complain about the input data like this "Malformed UTF-8 ..." since
380 any old eight-bit data is not legal UTF-8.
382 Note for code authors: if you want to enable your users to use UTF-8
383 as their default encoding but in your code still have eight-bit I/O streams
384 (such as images or zip files), you need to explicitly open() or binmode()
385 with C<:bytes> (see L<perlfunc/open> and L<perlfunc/binmode>), or you
386 can just use C<binmode(FH)> (nice for pre-5.8.0 backward compatibility).
390 File handles can translate character encodings from/to Perl's internal
391 Unicode form on read/write via the ":encoding()" layer.
395 File handles can be opened to "in memory" files held in Perl scalars via:
397 open($fh,'>', \$variable) || ...
401 Anonymous temporary files are available without need to
402 'use FileHandle' or other module via
404 open($fh,"+>", undef) || ...
406 That is a literal undef, not an undefined value.
410 The list form of C<open> is now implemented for pipes (at least on UNIX):
412 open($fh,"-|", 'cat', '/etc/motd')
414 creates a pipe, and runs the equivalent of exec('cat', '/etc/motd') in
419 If your locale environment variables (LANGUAGE, LC_ALL, LC_CTYPE, LANG)
420 contain the strings 'UTF-8' or 'UTF8' (case-insensitive matching),
421 the default encoding of your STDIN, STDOUT, and STDERR, and of
422 B<any subsequent file open>, is UTF-8.
426 =head2 Restricted Hashes
428 A restricted hash is restricted to a certain set of keys, no keys
429 outside the set can be added. Also individual keys can be restricted
430 so that the key cannot be deleted and the value cannot be changed.
431 No new syntax is involved: the Hash::Util module is the interface.
435 Perl used to be fragile in that signals arriving at inopportune moments
436 could corrupt Perl's internal state. Now Perl postpones handling of
437 signals until it's safe (between opcodes).
439 This change may have surprising side effects because signals no longer
440 interrupt Perl instantly. Perl will now first finish whatever it was
441 doing, like finishing an internal operation (like sort()) or an
442 external operation (like an I/O operation), and only then look at any
443 arrived signals (and before starting the next operation). No more corrupt
444 internal state since the current operation is always finished first,
445 but the signal may take more time to get heard. Note that breaking
446 out from potentially blocking operations should still work, though.
448 =head2 Unicode Overhaul
450 Unicode in general should be now much more usable than in Perl 5.6.0
451 (or even in 5.6.1). Unicode can be used in hash keys, Unicode in
452 regular expressions should work now, Unicode in tr/// should work now,
453 Unicode in I/O should work now. See L<perluniintro> for introduction
454 and L<perlunicode> for details.
460 The Unicode Character Database coming with Perl has been upgraded
461 to Unicode 3.2.0. For more information, see http://www.unicode.org/ .
462 [561+] (5.6.1 has UCD 3.0.1.)
466 For developers interested in enhancing Perl's Unicode capabilities:
467 almost all the UCD files are included with the Perl distribution in
468 the F<lib/unicore> subdirectory. The most notable omission, for space
469 considerations, is the Unihan database.
473 The properties \p{Blank} and \p{SpacePerl} have been added. "Blank" is like
474 C isblank(), that is, it contains only "horizontal whitespace" (the space
475 character is, the newline isn't), and the "SpacePerl" is the Unicode
476 equivalent of C<\s> (\p{Space} isn't, since that includes the vertical
477 tabulator character, whereas C<\s> doesn't.)
479 See "New Unicode Properties" earlier in this document for additional
480 information on changes with Unicode properties.
484 =head2 Understanding of Numbers
486 In general a lot of fixing has happened in the area of Perl's
487 understanding of numbers, both integer and floating point. Since in
488 many systems the standard number parsing functions like C<strtoul()>
489 and C<atof()> seem to have bugs, Perl tries to work around their
490 deficiencies. This results hopefully in more accurate numbers.
492 Perl now tries internally to use integer values in numeric conversions
493 and basic arithmetics (+ - * /) if the arguments are integers, and
494 tries also to keep the results stored internally as integers.
495 This change leads to often slightly faster and always less lossy
496 arithmetics. (Previously Perl always preferred floating point numbers
499 =head2 Arrays now always interpolate into double-quoted strings [561]
501 In double-quoted strings, arrays now interpolate, no matter what. The
502 behavior in earlier versions of perl 5 was that arrays would interpolate
503 into strings if the array had been mentioned before the string was
504 compiled, and otherwise Perl would raise a fatal compile-time error.
505 In versions 5.000 through 5.003, the error was
507 Literal @example now requires backslash
509 In versions 5.004_01 through 5.6.0, the error was
511 In string, @example now must be written as \@example
513 The idea here was to get people into the habit of writing
514 C<"fred\@example.com"> when they wanted a literal C<@> sign, just as
515 they have always written C<"Give me back my \$5"> when they wanted a
518 Starting with 5.6.1, when Perl now sees an C<@> sign in a
519 double-quoted string, it I<always> attempts to interpolate an array,
520 regardless of whether or not the array has been used or declared
521 already. The fatal error has been downgraded to an optional warning:
523 Possible unintended interpolation of @example in string
525 This warns you that C<"fred@example.com"> is going to turn into
526 C<fred.com> if you don't backslash the C<@>.
527 See http://www.plover.com/~mjd/perl/at-error.html for more details
528 about the history here.
530 =head2 Miscellaneous Changes
536 AUTOLOAD is now lvaluable, meaning that you can add the :lvalue attribute
537 to AUTOLOAD subroutines and you can assign to the AUTOLOAD return value.
541 The $Config{byteorder} (and corresponding BYTEORDER in config.h) was
542 previously wrong in platforms if sizeof(long) was 4, but sizeof(IV)
543 was 8. The byteorder was only sizeof(long) bytes long (1234 or 4321),
544 but now it is correctly sizeof(IV) bytes long, (12345678 or 87654321).
545 (This problem didn't affect Windows platforms.)
547 Also, $Config{byteorder} is now computed dynamically--this is more
548 robust with "fat binaries" where an executable image contains binaries
549 for more than one binary platform, and when cross-compiling.
553 C<perl -d:Module=arg,arg,arg> now works (previously one couldn't pass
554 in multiple arguments.)
558 C<do> followed by a bareword now ensures that this bareword isn't
559 a keyword (to avoid a bug where C<do q(foo.pl)> tried to call a
560 subroutine called C<q>). This means that for example instead of
561 C<do format()> you must write C<do &format()>.
565 The builtin dump() now gives an optional warning
566 C<dump() better written as CORE::dump()>,
567 meaning that by default C<dump(...)> is resolved as the builtin
568 dump() which dumps core and aborts, not as (possibly) user-defined
569 C<sub dump>. To call the latter, qualify the call as C<&dump(...)>.
570 (The whole dump() feature is to considered deprecated, and possibly
571 removed/changed in future releases.)
575 chomp() and chop() are now overridable. Note, however, that their
576 prototype (as given by C<prototype("CORE::chomp")> is undefined,
577 because it cannot be expressed and therefore one cannot really write
578 replacements to override these builtins.
582 END blocks are now run even if you exit/die in a BEGIN block.
583 Internally, the execution of END blocks is now controlled by
584 PL_exit_flags & PERL_EXIT_DESTRUCT_END. This enables the new
585 behaviour for Perl embedders. This will default in 5.10. See
590 Formats now support zero-padded decimal fields.
594 Lvalue subroutines can now return C<undef> in list context. However,
595 the lvalue subroutine feature still remains experimental. [561+]
599 A lost warning "Can't declare ... dereference in my" has been
600 restored (Perl had it earlier but it became lost in later releases.)
604 A new special regular expression variable has been introduced:
605 C<$^N>, which contains the most-recently closed group (submatch).
609 C<no Module;> does not produce an error even if Module does not have an
610 unimport() method. This parallels the behavior of C<use> vis-a-vis
615 The numerical comparison operators return C<undef> if either operand
616 is a NaN. Previously the behaviour was unspecified.
620 C<our> can now have an experimental optional attribute C<unique> that
621 affects how global variables are shared among multiple interpreters,
626 The following builtin functions are now overridable: each(), keys(),
627 pop(), push(), shift(), splice(), unshift(). [561]
631 C<pack() / unpack()> can now group template letters with C<()> and then
632 apply repetition/count modifiers on the groups.
636 C<pack() / unpack()> can now process the Perl internal numeric types:
637 IVs, UVs, NVs-- and also long doubles, if supported by the platform.
638 The template letters are C<j>, C<J>, C<F>, and C<D>.
642 C<pack('U0a*', ...)> can now be used to force a string to UTF8.
646 my __PACKAGE__ $obj now works. [561]
650 POSIX::sleep() now returns the number of I<unslept> seconds
651 (as the POSIX standard says), as opposed to CORE::sleep() which
652 returns the number of slept seconds.
656 The printf() and sprintf() now support parameter reordering using the
657 C<%\d+\$> and C<*\d+\$> syntaxes. For example
659 print "%2\$s %1\$s\n", "foo", "bar";
661 will print "bar foo\n". This feature helps in writing
662 internationalised software, and in general when the order
663 of the parameters can vary.
667 The (\&) prototype now works properly. [561]
671 prototype(\[$@%&]) is now available to implicitly create references
672 (useful for example if you want to emulate the tie() interface).
676 A new command-line option, C<-t> is available. It is the
677 little brother of C<-T>: instead of dying on taint violations,
678 lexical warnings are given. B<This is only meant as a temporary
679 debugging aid while securing the code of old legacy applications.
680 This is not a substitute for -T.>
684 In other taint news, the C<exec LIST> and C<system LIST> have now been
685 considered too risky (think C<exec @ARGV>: it can start any program
686 with any arguments), and now the said forms cause a warning under
687 lexical warnings. You should carefully launder the arguments to
688 guarantee their validity. In future releases of Perl the forms will
689 become fatal errors so consider starting laundering now.
693 Tied hash interfaces are now required to have the EXISTS and DELETE
694 methods (either own or inherited).
698 If tr/// is just counting characters, it doesn't attempt to
703 untie() will now call an UNTIE() hook if it exists. See L<perltie>
708 L<utime> now supports C<utime undef, undef, @files> to change the
709 file timestamps to the current time.
713 The rules for allowing underscores (underbars) in numeric constants
714 have been relaxed and simplified: now you can have an underscore
715 simply B<between digits>.
719 Rather than relying on C's argv[0] (which may not contain a full pathname)
720 where possible $^X is now set by asking the operating system.
721 (eg by reading F</proc/self/exe> on Linux, F</proc/curproc/file> on FreeBSD)
725 A new variable, C<${^TAINT}>, indicates whether taint mode is enabled.
729 You can now override the readline() builtin, and this overrides also
730 the <FILEHANDLE> angle bracket operator.
734 The command-line options -s and -F are now recognized on the shebang
739 Use of the C</c> match modifier without an accompanying C</g> modifier
740 elicits a new warning: C<Use of /c modifier is meaningless without /g>.
742 Use of C</c> in substitutions, even with C</g>, elicits
743 C<Use of /c modifier is meaningless in s///>.
745 Use of C</g> with C<split> elicits C<Use of /g modifier is meaningless
750 Support for the C<CLONE> special subroutine had been added.
751 With ithreads, when a new thread is created, all Perl data is cloned,
752 however non-Perl data cannot be cloned automatically. In C<CLONE> you
753 can do whatever you need to do, like for example handle the cloning of
754 non-Perl data, if necessary. C<CLONE> will be executed once for every
755 package that has it defined or inherited. It will be called in the
756 context of the new thread, so all modifications are made in the new area.
762 =head1 Modules and Pragmata
764 =head2 New Modules and Pragmata
770 C<Attribute::Handlers>, originally by Damian Conway and now maintained
771 by Arthur Bergman, allows a class to define attribute handlers.
774 use Attribute::Handlers;
775 sub Wolf :ATTR(SCALAR) { print "howl!\n" }
777 # later, in some package using or inheriting from MyPack...
779 my MyPack $Fluffy : Wolf; # the attribute handler Wolf will be called
781 Both variables and routines can have attribute handlers. Handlers can
782 be specific to type (SCALAR, ARRAY, HASH, or CODE), or specific to the
783 exact compilation phase (BEGIN, CHECK, INIT, or END).
784 See L<Attribute::Handlers>.
788 C<B::Concise>, by Stephen McCamant, is a new compiler backend for
789 walking the Perl syntax tree, printing concise info about ops.
790 The output is highly customisable. See L<B::Concise>. [561+]
794 The new bignum, bigint, and bigrat pragmas, by Tels, implement
795 transparent bignum support (using the Math::BigInt, Math::BigFloat,
796 and Math::BigRat backends).
800 C<Class::ISA>, by Sean Burke, is a module for reporting the search
801 path for a class's ISA tree. See L<Class::ISA>.
805 C<Cwd> now has a split personality: if possible, an XS extension is
806 used, (this will hopefully be faster, more secure, and more robust)
807 but if not possible, the familiar Perl implementation is used.
811 C<Devel::PPPort>, originally by Kenneth Albanowski and now
812 maintained by Paul Marquess, has been added. It is primarily used
813 by C<h2xs> to enhance portability of XS modules between different
814 versions of Perl. See L<Devel::PPPort>.
818 C<Digest>, frontend module for calculating digests (checksums), from
819 Gisle Aas, has been added. See L<Digest>.
823 C<Digest::MD5> for calculating MD5 digests (checksums) as defined in
824 RFC 1321, from Gisle Aas, has been added. See L<Digest::MD5>.
826 use Digest::MD5 'md5_hex';
828 $digest = md5_hex("Thirsty Camel");
830 print $digest, "\n"; # 01d19d9d2045e005c3f1b80e8b164de1
832 NOTE: the C<MD5> backward compatibility module is deliberately not
833 included since its further use is discouraged.
837 C<Encode>, originally by Nick Ing-Simmons and now maintained by Dan
838 Kogai, provides a mechanism to translate between different character
839 encodings. Support for Unicode, ISO-8859-1, and ASCII are compiled in
840 to the module. Several other encodings (like the rest of the
841 ISO-8859, CP*/Win*, Mac, KOI8-R, three variants EBCDIC, Chinese,
842 Japanese, and Korean encodings) are included and can be loaded at
843 runtime. (For space considerations, the largest Chinese encodings
844 have been separated into their own CPAN module, Encode::HanExtra,
845 which Encode will use if available). See L<Encode>.
847 Any encoding supported by Encode module is also available to the
848 ":encoding()" layer if PerlIO is used.
852 C<Hash::Util> is the interface to the new I<restricted hashes>
853 feature. (Implemented by Jeffrey Friedl, Nick Ing-Simmons, and
854 Michael Schwern.) See L<Hash::Util>.
858 C<I18N::Langinfo> can be used to query locale information.
859 See L<I18N::Langinfo>.
863 C<I18N::LangTags>, by Sean Burke, has functions for dealing with
864 RFC3066-style language tags. See L<I18N::LangTags>.
868 C<ExtUtils::Constant>, by Nicholas Clark, is a new tool for extension
869 writers for generating XS code to import C header constants.
870 See L<ExtUtils::Constant>.
874 C<Filter::Simple>, by Damian Conway, is an easy-to-use frontend to
875 Filter::Util::Call. See L<Filter::Simple>.
881 use Filter::Simple sub {
882 while (my ($from, $to) = splice @_, 0, 2) {
891 use MyFilter qr/red/ => 'green';
893 print "red\n"; # this code is filtered, will print "green\n"
894 print "bored\n"; # this code is filtered, will print "bogreen\n"
898 print "red\n"; # this code is not filtered, will print "red\n"
902 C<File::Temp>, by Tim Jenness, allows one to create temporary files
903 and directories in an easy, portable, and secure way. See L<File::Temp>.
908 C<Filter::Util::Call>, by Paul Marquess, provides you with the
909 framework to write I<source filters> in Perl. For most uses, the
910 frontend Filter::Simple is to be preferred. See L<Filter::Util::Call>.
914 C<if>, by Ilya Zakharevich, is a new pragma for conditional inclusion
919 L<libnet>, by Graham Barr, is a collection of perl5 modules related
920 to network programming. See L<Net::FTP>, L<Net::NNTP>, L<Net::Ping>
921 (not part of libnet, but related), L<Net::POP3>, L<Net::SMTP>,
924 Perl installation leaves libnet unconfigured; use F<libnetcfg>
929 C<List::Util>, by Graham Barr, is a selection of general-utility
930 list subroutines, such as sum(), min(), first(), and shuffle().
935 C<Locale::Constants>, C<Locale::Country>, C<Locale::Currency>
936 C<Locale::Language>, and L<Locale::Script>, by Neil Bowers, have
937 been added. They provide the codes for various locale standards, such
938 as "fr" for France, "usd" for US Dollar, and "ja" for Japanese.
942 $country = code2country('jp'); # $country gets 'Japan'
943 $code = country2code('Norway'); # $code gets 'no'
945 See L<Locale::Constants>, L<Locale::Country>, L<Locale::Currency>,
946 and L<Locale::Language>.
950 C<Locale::Maketext>, by Sean Burke, is a localization framework. See
951 L<Locale::Maketext>, and L<Locale::Maketext::TPJ13>. The latter is an
952 article about software localization, originally published in The Perl
953 Journal #13, and republished here with kind permission.
957 C<Math::BigRat> for big rational numbers, to accompany Math::BigInt and
958 Math::BigFloat, from Tels. See L<Math::BigRat>.
962 C<Memoize> can make your functions faster by trading space for time,
963 from Mark-Jason Dominus. See L<Memoize>.
967 C<MIME::Base64>, by Gisle Aas, allows you to encode data in base64,
968 as defined in RFC 2045 - I<MIME (Multipurpose Internet Mail
973 $encoded = encode_base64('Aladdin:open sesame');
974 $decoded = decode_base64($encoded);
976 print $encoded, "\n"; # "QWxhZGRpbjpvcGVuIHNlc2FtZQ=="
982 C<MIME::QuotedPrint>, by Gisle Aas, allows you to encode data
983 in quoted-printable encoding, as defined in RFC 2045 - I<MIME
984 (Multipurpose Internet Mail Extensions)>.
986 use MIME::QuotedPrint;
988 $encoded = encode_qp("Smiley in Unicode: \x{263a}");
989 $decoded = decode_qp($encoded);
991 print $encoded, "\n"; # "Smiley in Unicode: =263A"
993 MIME::QuotedPrint has been enhanced to provide the basic methods
994 necessary to use it with PerlIO::Via as in :
996 use MIME::QuotedPrint;
997 open($fh,">Via(MIME::QuotedPrint)",$path);
999 See L<MIME::QuotedPrint>.
1003 C<NEXT>, by Damian Conway, is a pseudo-class for method redispatch.
1008 C<open> is a new pragma for setting the default I/O layers
1013 C<PerlIO::Scalar>, by Nick Ing-Simmons, provides the implementation
1014 of IO to "in memory" Perl scalars as discussed above. It also serves
1015 as an example of a loadable PerlIO layer. Other future possibilities
1016 include PerlIO::Array and PerlIO::Code. See L<PerlIO::Scalar>.
1020 C<PerlIO::Via>, by Nick Ing-Simmons, acts as a PerlIO layer and wraps
1021 PerlIO layer functionality provided by a class (typically implemented
1024 use MIME::QuotedPrint;
1025 open($fh,">Via(MIME::QuotedPrint)",$path);
1027 This will automatically convert everything output to C<$fh>
1028 to Quoted-Printable. See L<PerlIO::Via>.
1032 C<Pod::ParseLink>, by Russ Allbery, has been added,
1033 to parse LZ<><> links in pods as described in the new
1038 C<Pod::Text::Overstrike>, by Joe Smith, has been added.
1039 It converts POD data to formatted overstrike text.
1040 See L<Pod::Text::Overstrike>. [561+]
1044 C<Scalar::Util> is a selection of general-utility scalar subroutines,
1045 such as blessed(), reftype(), and tainted(). See L<Scalar::Util>.
1049 C<sort> is a new pragma for controlling the behaviour of sort().
1053 C<Storable> gives persistence to Perl data structures by allowing the
1054 storage and retrieval of Perl data to and from files in a fast and
1055 compact binary format. Because in effect Storable does serialisation
1056 of Perl data structures, with it you can also clone deep, hierarchical
1057 datastructures. Storable was originally created by Raphael Manfredi,
1058 but it is now maintained by Abhijit Menon-Sen. Storable has been
1059 enhanced to understand the two new hash features, Unicode keys and
1060 restricted hashes. See L<Storable>.
1064 C<Switch>, by Damian Conway, has been added. Just by saying
1068 you have C<switch> and C<case> available in Perl.
1074 case 1 { print "number 1" }
1075 case "a" { print "string a" }
1076 case [1..10,42] { print "number in list" }
1077 case (@array) { print "number in list" }
1078 case /\w+/ { print "pattern" }
1079 case qr/\w+/ { print "pattern" }
1080 case (%hash) { print "entry in hash" }
1081 case (\%hash) { print "entry in hash" }
1082 case (\&sub) { print "arg to subroutine" }
1083 else { print "previous case not true" }
1090 C<Test::More>, by Michael Schwern, is yet another framework for writing
1091 test scripts, more extensive than Test::Simple. See L<Test::More>.
1095 C<Test::Simple>, by Michael Schwern, has basic utilities for writing
1096 tests. See L<Test::Simple>.
1100 C<Text::Balanced>, by Damian Conway, has been added, for extracting
1101 delimited text sequences from strings.
1103 use Text::Balanced 'extract_delimited';
1105 ($a, $b) = extract_delimited("'never say never', he never said", "'", '');
1107 $a will be "'never say never'", $b will be ', he never said'.
1109 In addition to extract_delimited(), there are also extract_bracketed(),
1110 extract_quotelike(), extract_codeblock(), extract_variable(),
1111 extract_tagged(), extract_multiple(), gen_delimited_pat(), and
1112 gen_extract_tagged(). With these, you can implement rather advanced
1113 parsing algorithms. See L<Text::Balanced>.
1117 C<threads>, by Arthur Bergman, is an interface to interpreter threads.
1118 Interpreter threads (ithreads) is the new thread model introduced in
1119 Perl 5.6 but only available as an internal interface for extension
1120 writers (and for Win32 Perl for C<fork()> emulation). See L<threads>,
1121 L<threads::shared>, and L<perlthrtut>.
1125 C<threads::shared>, by Arthur Bergman, allows data sharing for
1126 interpreter threads. In the ithreads model any data sharing between
1127 threads must be explicit, as opposed to the old 5.005 thread model
1128 where data sharing was implicit. See L<threads::shared>.
1132 C<Tie::File>, by Mark-Jason Dominus, associates a Perl array with the
1133 lines of a file. See L<Tie::File>.
1137 C<Tie::Memoize>, by Ilya Zakharevich, provides on-demand loaded hashes.
1138 See L<Tie::Memoize>.
1142 C<Tie::RefHash::Nestable>, by Edward Avis, allows storing hash
1143 references (unlike the standard Tie::RefHash) The module is contained
1144 within Tie::RefHash. See L<Tie::RefHash>.
1148 C<Time::HiRes>, by Douglas E. Wegscheid, provides high resolution
1149 timing (ualarm, usleep, and gettimeofday). See L<Time::HiRes>.
1153 C<Unicode::UCD> offers a querying interface to the Unicode Character
1154 Database. See L<Unicode::UCD>.
1158 C<Unicode::Collate>, by SADAHIRO Tomoyuki, implements the UCA
1159 (Unicode Collation Algorithm) for sorting Unicode strings.
1160 See L<Unicode::Collate>.
1164 C<Unicode::Normalize>, by SADAHIRO Tomoyuki, implements the various
1165 Unicode normalization forms. See L<Unicode::Normalize>.
1169 C<XS::APItest>, by Tim Jenness, is a test extension that exercises XS
1170 APIs. Currently only C<printf()> is tested: how to output various
1171 basic data types from XS.
1175 C<XS::Typemap>, by Tim Jenness, is a test extension that exercises
1176 XS typemaps. Nothing gets installed, but the code is worth studying
1177 for extension writers.
1181 =head2 Updated And Improved Modules and Pragmata
1187 The following independently supported modules have been updated to the
1188 newest versions from CPAN: CGI, CPAN, DB_File, File::Spec, File::Temp,
1189 Getopt::Long, Math::BigFloat, Math::BigInt, the podlators bundle
1190 (Pod::Man, Pod::Text), Pod::LaTeX [561+], Pod::Parser, Storable,
1191 Term::ANSIColor, Test, Text-Tabs+Wrap.
1195 attributes::reftype() now works on tied arguments.
1199 AutoLoader can now be disabled with C<no AutoLoader;>.
1203 B::Deparse has been significantly enhanced by Robin Houston. It can
1204 now deparse almost all of the standard test suite (so that the tests
1205 still succeed). There is a make target "test.deparse" for trying this
1210 Carp now has better interface documentation, and the @CARP_NOT
1211 interface has been added to get optional control over where errors
1212 are reported independently of @ISA, by Ben Tilly.
1216 Class::Struct can now define the classes in compile time.
1220 Class::Struct now assigns the array/hash element if the accessor
1221 is called with an array/hash element as the B<sole> argument.
1225 The return value of Cwd::fastcwd() is now tainted.
1229 Data::Dumper now has an option to sort hashes.
1233 Data::Dumper now has an option to dump code references
1238 DB_File now supports newer Berkeley DB versions, among
1243 Devel::Peek now has an interface for the Perl memory statistics
1244 (this works only if you are using perl's malloc, and if you have
1245 compiled with debugging).
1249 The English module can now be used without the infamous performance
1252 use English '-no_match_vars';
1254 (Assuming, of course, that you don't need the troublesome variables
1255 C<$`>, C<$&>, or C<$'>.) Also, introduced C<@LAST_MATCH_START> and
1256 C<@LAST_MATCH_END> English aliases for C<@-> and C<@+>.
1260 ExtUtils::MakeMaker has been significantly cleaned up and fixed.
1261 The enhanced version has also been backported to earlier releases
1262 of Perl and submitted to CPAN so that the earlier releases can
1267 The arguments of WriteMakefile() in Makefile.PL are now checked
1268 for sanity much more carefully than before. This may cause new
1269 warnings when modules are being installed. See L<ExtUtils::MakeMaker>
1274 ExtUtils::MakeMaker now uses File::Spec internally, which hopefully
1275 leads to better portability.
1279 Fcntl, Socket, and Sys::Syslog have been rewritten by Nicholas Clark
1280 to use the new-style constant dispatch section (see L<ExtUtils::Constant>).
1281 This means that they will be more robust and hopefully faster.
1285 File::Find now chdir()s correctly when chasing symbolic links. [561]
1289 File::Find now has pre- and post-processing callbacks. It also
1290 correctly changes directories when chasing symbolic links. Callbacks
1291 (naughtily) exiting with "next;" instead of "return;" now work.
1295 File::Find is now (again) reentrant. It also has been made
1300 The warnings issued by File::Find now belong to their own category.
1301 You can enable/disable them with C<use/no warnings 'File::Find';>.
1305 File::Glob::glob() has been renamed to File::Glob::bsd_glob()
1306 because the name clashes with the builtin glob(). The older
1307 name is still available for compatibility, but is deprecated. [561]
1311 File::Glob now supports C<GLOB_LIMIT> constant to limit the size of
1312 the returned list of filenames.
1316 IPC::Open3 now allows the use of numeric file descriptors.
1320 IO::Socket now has an atmark() method, which returns true if the socket
1321 is positioned at the out-of-band mark. The method is also exportable
1322 as a sockatmark() function.
1326 IO::Socket::INET failed to open the specified port if the service name
1327 was not known. It now correctly uses the supplied port number as is. [561]
1331 IO::Socket::INET has support for the ReusePort option (if your
1332 platform supports it). The Reuse option now has an alias, ReuseAddr.
1333 For clarity, you may want to prefer ReuseAddr.
1337 IO::Socket::INET now supports a value of zero for C<LocalPort>
1338 (usually meaning that the operating system will make one up.)
1342 'use lib' now works identically to @INC. Removing directories
1343 with 'no lib' now works.
1347 Math::BigFloat and Math::BigInt have undergone a full rewrite by Tels.
1348 They are now magnitudes faster, and they support various bignum
1349 libraries such as GMP and PARI as their backends.
1353 Math::Complex handles inf, NaN etc., better.
1357 Net::Ping has been considerably enhanced by Rob Brown: multihoming is
1358 now supported, Win32 functionality is better, there is now time
1359 measuring functionality (optionally high-resolution using
1360 Time::HiRes), and there is now "external" protocol which uses
1361 Net::Ping::External module which runs your external ping utility and
1362 parses the output. A version of Net::Ping::External is available in
1365 Note that some of the Net::Ping tests are disabled when running
1366 under the Perl distribution since one cannot assume one or more
1367 of the following: enabled echo port at localhost, full Internet
1368 connectivity, or sympathetic firewalls. You can set the environment
1369 variable PERL_TEST_Net_Ping to "1" (one) before running the Perl test
1370 suite to enable all the Net::Ping tests.
1374 POSIX::sigaction() is now much more flexible and robust.
1375 You can now install coderef handlers, 'DEFAULT', and 'IGNORE'
1376 handlers, installing new handlers was not atomic.
1380 In Safe, C<%INC> is now localised in a Safe compartment so that
1385 In SDBM_File on dosish platforms, some keys went missing because of
1386 lack of support for files with "holes". A workaround for the problem
1391 In Search::Dict one can now have a pre-processing hook for the
1392 lines being searched.
1396 The Shell module now has an OO interface.
1400 In Sys::Syslog there is now a failover mechanism that will go
1401 through alternative connection mechanisms until the message
1402 is successfully logged.
1406 The Test module has been significantly enhanced.
1410 Time::Local::timelocal() does not handle fractional seconds anymore.
1411 The rationale is that neither does localtime(), and timelocal() and
1412 localtime() are supposed to be inverses of each other.
1416 The vars pragma now supports declaring fully qualified variables.
1417 (Something that C<our()> does not and will not support.)
1421 The C<utf8::> name space (as in the pragma) provides various
1422 Perl-callable functions to provide low level access to Perl's
1423 internal Unicode representation. At the moment only length()
1424 has been implemented.
1428 =head1 Utility Changes
1434 Emacs perl mode (emacs/cperl-mode.el) has been updated to version
1439 F<emacs/e2ctags.pl> is now much faster.
1443 C<enc2xs> is a tool for people adding their own encodings to the
1448 C<h2ph> now supports C trigraphs.
1452 C<h2xs> now produces a template README.
1456 C<h2xs> now uses C<Devel::PPPort> for better portability between
1457 different versions of Perl.
1461 C<h2xs> uses the new L<ExtUtils::Constant|ExtUtils::Constant> module
1462 which will affect newly created extensions that define constants.
1463 Since the new code is more correct (if you have two constants where the
1464 first one is a prefix of the second one, the first constant B<never>
1465 got defined), less lossy (it uses integers for integer constant,
1466 as opposed to the old code that used floating point numbers even for
1467 integer constants), and slightly faster, you might want to consider
1468 regenerating your extension code (the new scheme makes regenerating
1469 easy). L<h2xs> now also supports C trigraphs.
1473 C<libnetcfg> has been added to configure libnet.
1477 C<perlbug> is now much more robust. It also sends the bug report to
1478 perl.org, not perl.com.
1482 C<perlcc> has been rewritten and its user interface (that is,
1483 command line) is much more like that of the UNIX C compiler, cc.
1484 (The perlbc tools has been removed. Use C<perlcc -B> instead.)
1485 B<Note that perlcc is still considered very experimental and
1490 C<perlivp> is a new Installation Verification Procedure utility
1491 for running any time after installing Perl.
1495 C<piconv> is an implementation of the character conversion utility
1496 C<iconv>, demonstrating the new Encode module.
1500 C<pod2html> now allows specifying a cache directory.
1504 C<pod2html> now produces XHTML 1.0.
1508 C<pod2html> now understands POD written using different line endings
1509 (PC-like CRLF versus UNIX-like LF versus MacClassic-like CR).
1513 C<s2p> has been completely rewritten in Perl. (It is in fact a full
1514 implementation of sed in Perl: you can use the sed functionality by
1515 using the C<psed> utility.)
1519 C<xsubpp> now understands POD documentation embedded in the *.xs
1524 C<xsubpp> now supports the OUT keyword.
1528 =head1 New Documentation
1534 perl56delta details the changes between the 5.005 release and the
1539 perlclib documents the internal replacements for standard C library
1540 functions. (Interesting only for extension writers and Perl core
1545 perldebtut is a Perl debugging tutorial. [561+]
1549 perlebcdic contains considerations for running Perl on EBCDIC
1554 perlintro is a gentle introduction to Perl.
1558 perliol documents the internals of PerlIO with layers.
1562 perlmodstyle is a style guide for writing modules.
1566 perlnewmod tells about writing and submitting a new module. [561+]
1570 perlpacktut is a pack() tutorial.
1574 perlpod has been rewritten to be clearer and to record the best
1575 practices gathered over the years.
1579 perlpodspec is a more formal specification of the pod format,
1580 mainly of interest for writers of pod applications, not to
1581 people writing in pod.
1585 perlretut is a regular expression tutorial. [561+]
1589 perlrequick is a regular expressions quick-start guide.
1590 Yes, much quicker than perlretut. [561]
1594 perltodo has been updated.
1598 perltootc has been renamed as perltooc (to not to conflict
1599 with perltoot in filesystems restricted to "8.3" names).
1603 perluniintro is an introduction to using Unicode in Perl.
1604 (perlunicode is more of a detailed reference and background
1609 perlutil explains the command line utilities packaged with the Perl
1610 distribution. [561+]
1614 The following platform-specific documents are available before
1615 the installation as README.I<platform>, and after the installation
1618 perlaix perlamiga perlapollo perlbeos perlbs2000
1619 perlce perlcygwin perldgux perldos perlepoc perlfreebsd perlhpux
1620 perlhurd perlirix perlmachten perlmacos perlmint perlmpeix
1621 perlnetware perlos2 perlos390 perlplan9 perlqnx perlsolaris
1622 perltru64 perluts perlvmesa perlvms perlvos perlwin32
1624 These documents usually detail one or more of the following subjects:
1625 configuring, building, testing, installing, and sometimes also using
1626 Perl on the said platform.
1628 Eastern Asian Perl users are now welcomed in their own languages:
1629 README.jp (Japanese), README.ko (Korean), README.cn (simplified
1630 Chinese) and README.tw (traditional Chinese), which are written in
1631 normal pod but encoded in EUC-JP, EUC-KR, EUC-CN and Big5. These
1632 will get installed as
1634 perljp perlko perlcn perltw
1640 The documentation for the POSIX-BC platform is called "BS2000", to avoid
1641 confusion with the Perl POSIX module.
1645 The documentation for the WinCE platform is called perlce (README.ce
1646 in the source code kit), to avoid confusion with the perlwin32
1647 documentation on 8.3-restricted filesystems.
1651 =head1 Performance Enhancements
1657 map() could get pathologically slow when the result list it generates
1658 is larger than the source list. The performance has been improved for
1659 common scenarios. [561]
1663 sort() is also fully reentrant, in the sense that the sort function
1664 can itself call sort(). This did not work reliably in previous
1669 sort() has been changed to use primarily mergesort internally as
1670 opposed to the earlier quicksort. For very small lists this may
1671 result in slightly slower sorting times, but in general the speedup
1672 should be at least 20%. Additional bonuses are that the worst case
1673 behaviour of sort() is now better (in computer science terms it now
1674 runs in time O(N log N), as opposed to quicksort's Theta(N**2)
1675 worst-case run time behaviour), and that sort() is now stable
1676 (meaning that elements with identical keys will stay ordered as they
1677 were before the sort). See the C<sort> pragma for information.
1679 The story in more detail: suppose you want to serve yourself a little
1682 @digits = ( 3,1,4,1,5,9 );
1684 A numerical sort of the digits will yield (1,1,3,4,5,9), as expected.
1685 Which C<1> comes first is hard to know, since one C<1> looks pretty
1686 much like any other. You can regard this as totally trivial,
1687 or somewhat profound. However, if you just want to sort the even
1688 digits ahead of the odd ones, then what will
1690 sort { ($a % 2) <=> ($b % 2) } @digits;
1692 yield? The only even digit, C<4>, will come first. But how about
1693 the odd numbers, which all compare equal? With the quicksort algorithm
1694 used to implement Perl 5.6 and earlier, the order of ties is left up
1695 to the sort. So, as you add more and more digits of Pi, the order
1696 in which the sorted even and odd digits appear will change.
1697 and, for sufficiently large slices of Pi, the quicksort algorithm
1698 in Perl 5.8 won't return the same results even if reinvoked with the
1699 same input. The justification for this rests with quicksort's
1700 worst case behavior. If you run
1702 sort { $a <=> $b } ( 1 .. $N , 1 .. $N );
1704 (something you might approximate if you wanted to merge two sorted
1705 arrays using sort), doubling $N doesn't just double the quicksort time,
1706 it I<quadruples> it. Quicksort has a worst case run time that can
1707 grow like N**2, so-called I<quadratic> behaviour, and it can happen
1708 on patterns that may well arise in normal use. You won't notice this
1709 for small arrays, but you I<will> notice it with larger arrays,
1710 and you may not live long enough for the sort to complete on arrays
1711 of a million elements. So the 5.8 quicksort scrambles large arrays
1712 before sorting them, as a statistical defence against quadratic behaviour.
1713 But that means if you sort the same large array twice, ties may be
1714 broken in different ways.
1716 Because of the unpredictability of tie-breaking order, and the quadratic
1717 worst-case behaviour, quicksort was I<almost> replaced completely with
1718 a stable mergesort. I<Stable> means that ties are broken to preserve
1719 the original order of appearance in the input array. So
1721 sort { ($a % 2) <=> ($b % 2) } (3,1,4,1,5,9);
1723 will yield (4,3,1,1,5,9), guaranteed. The even and odd numbers
1724 appear in the output in the same order they appeared in the input.
1725 Mergesort has worst case O(N log N) behaviour, the best value
1726 attainable. And, ironically, this mergesort does particularly
1727 well where quicksort goes quadratic: mergesort sorts (1..$N, 1..$N)
1728 in O(N) time. But quicksort was rescued at the last moment because
1729 it is faster than mergesort on certain inputs and platforms.
1730 For example, if you really I<don't> care about the order of even
1731 and odd digits, quicksort will run in O(N) time; it's very good
1732 at sorting many repetitions of a small number of distinct elements.
1733 The quicksort divide and conquer strategy works well on platforms
1734 with relatively small, very fast, caches. Eventually, the problem gets
1735 whittled down to one that fits in the cache, from which point it
1736 benefits from the increased memory speed.
1738 Quicksort was rescued by implementing a sort pragma to control aspects
1739 of the sort. The B<stable> subpragma forces stable behaviour,
1740 regardless of algorithm. The B<_quicksort> and B<_mergesort>
1741 subpragmas are heavy-handed ways to select the underlying implementation.
1742 The leading C<_> is a reminder that these subpragmas may not survive
1743 beyond 5.8. More appropriate mechanisms for selecting the implementation
1744 exist, but they wouldn't have arrived in time to save quicksort.
1748 Hashes now use Bob Jenkins "One-at-a-Time" hashing key algorithm
1749 ( http://burtleburtle.net/bob/hash/doobs.html ). This algorithm is
1750 reasonably fast while producing a much better spread of values than
1751 the old hashing algorithm (originally by Chris Torek, later tweaked by
1752 Ilya Zakharevich). Hash values output from the algorithm on a hash of
1753 all 3-char printable ASCII keys comes much closer to passing the
1754 DIEHARD random number generation tests. According to perlbench, this
1755 change has not affected the overall speed of Perl.
1759 unshift() should now be noticeably faster.
1763 =head1 Installation and Configuration Improvements
1765 =head2 Generic Improvements
1771 INSTALL now explains how you can configure Perl to use 64-bit
1772 integers even on non-64-bit platforms.
1776 Policy.sh policy change: if you are reusing a Policy.sh file
1777 (see INSTALL) and you use Configure -Dprefix=/foo/bar and in the old
1778 Policy $prefix eq $siteprefix and $prefix eq $vendorprefix, all of
1779 them will now be changed to the new prefix, /foo/bar. (Previously
1780 only $prefix changed.) If you do not like this new behaviour,
1781 specify prefix, siteprefix, and vendorprefix explicitly.
1785 A new optional location for Perl libraries, otherlibdirs, is available.
1786 It can be used for example for vendor add-ons without disturbing Perl's
1787 own library directories.
1791 In many platforms, the vendor-supplied 'cc' is too stripped-down to
1792 build Perl (basically, 'cc' doesn't do ANSI C). If this seems
1793 to be the case and 'cc' does not seem to be the GNU C compiler
1794 'gcc', an automatic attempt is made to find and use 'gcc' instead.
1798 gcc needs to closely track the operating system release to avoid
1799 build problems. If Configure finds that gcc was built for a different
1800 operating system release than is running, it now gives a clearly visible
1801 warning that there may be trouble ahead.
1805 Since Perl 5.8 is not binary-compatible with previous releases
1806 of Perl, Configure no longer suggests including the 5.005
1811 Configure C<-S> can now run non-interactively. [561]
1815 Configure support for pdp11-style memory models has been removed due
1816 to obsolescence. [561]
1820 configure.gnu now works with options with whitespace in them.
1824 installperl now outputs everything to STDERR.
1828 Because PerlIO is now the default on most platforms, "-perlio" doesn't
1829 get appended to the $Config{archname} (also known as $^O) anymore.
1830 Instead, if you explicitly choose not to use perlio (Configure command
1831 line option -Uuseperlio), you will get "-stdio" appended.
1835 Another change related to the architecture name is that "-64all"
1836 (-Duse64bitall, or "maximally 64-bit") is appended only if your
1837 pointers are 64 bits wide. (To be exact, the use64bitall is ignored.)
1841 In AFS installations, one can configure the root of the AFS to be
1842 somewhere else than the default F</afs> by using the Configure
1843 parameter C<-Dafsroot=/some/where/else>.
1847 APPLLIB_EXP, a lesser-known configuration-time definition, has been
1848 documented. It can be used to prepend site-specific directories
1849 to Perl's default search path (@INC); see INSTALL for information.
1853 The version of Berkeley DB used when the Perl (and, presumably, the
1854 DB_File extension) was built is now available as
1855 C<@Config{qw(db_version_major db_version_minor db_version_patch)}>
1856 from Perl and as C<DB_VERSION_MAJOR_CFG DB_VERSION_MINOR_CFG
1857 DB_VERSION_PATCH_CFG> from C.
1861 Building Berkeley DB3 for compatibility modes for DB, NDBM, and ODBM
1862 has been documented in INSTALL.
1866 If you have CPAN access (either network or a local copy such as a
1867 CD-ROM) you can during specify extra modules to Configure to build and
1868 install with Perl using the -Dextras=... option. See INSTALL for
1873 In addition to config.over, a new override file, config.arch, is
1874 available. This file is supposed to be used by hints file writers
1875 for architecture-wide changes (as opposed to config.over which is
1876 for site-wide changes).
1880 If your file system supports symbolic links, you can build Perl outside
1881 of the source directory by
1883 mkdir /tmp/perl/build/directory
1884 cd /tmp/perl/build/directory
1885 sh /path/to/perl/source/Configure -Dmksymlinks ...
1887 This will create in /tmp/perl/build/directory a tree of symbolic links
1888 pointing to files in /path/to/perl/source. The original files are left
1889 unaffected. After Configure has finished, you can just say
1893 and Perl will be built and tested, all in /tmp/perl/build/directory.
1898 For Perl developers, several new make targets for profiling
1899 and debugging have been added; see L<perlhack>.
1905 Use of the F<gprof> tool to profile Perl has been documented in
1906 L<perlhack>. There is a make target called "perl.gprof" for
1907 generating a gprofiled Perl executable.
1911 If you have GCC 3, there is a make target called "perl.gcov" for
1912 creating a gcoved Perl executable for coverage analysis. See
1917 If you are on IRIX or Tru64 platforms, new profiling/debugging options
1918 have been added; see L<perlhack> for more information about pixie and
1925 Guidelines of how to construct minimal Perl installations have
1926 been added to INSTALL.
1930 The Thread extension is now not built at all under ithreads
1931 (C<Configure -Duseithreads>) because it wouldn't work anyway (the
1932 Thread extension requires being Configured with C<-Duse5005threads>).
1934 But note that the Thread.pm interface is now shared by both
1939 The Gconvert macro ($Config{d_Gconvert}) used by perl for stringifying
1940 floating-point numbers is now more picky about using sprintf %.*g
1941 rules for the conversion. Some platforms that used to use gcvt may
1942 now resort to the slower sprintf.
1946 The obsolete method of making a special (e.g., debugging) flavor
1949 make LIBPERL=libperld.a
1951 has been removed. Use -DDEBUGGING instead.
1955 =head2 New Or Improved Platforms
1957 For the list of platforms known to support Perl,
1958 see L<perlport/"Supported Platforms">.
1964 AIX dynamic loading should be now better supported.
1968 AIX should now work better with gcc, threads, and 64-bitness. Also the
1969 long doubles support in AIX should be better now. See L<perlaix>.
1973 AtheOS ( http://www.atheos.cx/ ) is a new platform.
1977 BeOS has been reclaimed.
1981 The DG/UX platform now supports 5.005-style threads.
1986 The DYNIX/ptx platform (also known as dynixptx) is supported at or
1991 EBCDIC platforms (z/OS (also known as OS/390), POSIX-BC, and VM/ESA)
1992 have been regained. Many test suite tests still fail and the
1993 co-existence of Unicode and EBCDIC isn't quite settled, but the
1994 situation is much better than with Perl 5.6. See L<perlos390>,
1995 L<perlbs2000> (for POSIX-BC), and L<perlvmesa> for more information.
1999 Building perl with -Duseithreads or -Duse5005threads now works under
2000 HP-UX 10.20 (previously it only worked under 10.30 or later). You will
2001 need a thread library package installed. See README.hpux. [561]
2005 Mac OS Classic is now supported in the mainstream source package
2006 (MacPerl has of course been available since perl 5.004 but now the
2007 source code bases of standard Perl and MacPerl have been synchronised)
2012 Mac OS X (or Darwin) should now be able to build Perl even on HFS+
2013 filesystems. (The case-insensitivity used to confuse the Perl build
2018 NCR MP-RAS is now supported. [561]
2022 All the NetBSD specific patches (except for the installation
2023 specific ones) have been merged back to the main distribution.
2027 NetWare from Novell is now supported. See L<perlnetware>.
2031 NonStop-UX is now supported. [561]
2035 NEC SUPER-UX is now supported.
2039 All the OpenBSD specific patches (except for the installation
2040 specific ones) have been merged back to the main distribution.
2044 Perl has been tested with the GNU pth userlevel thread package
2045 ( http://www.gnu.org/software/pth/pth.html ). All thread tests
2046 of Perl now work, but not without adding some yield()s to the tests,
2047 so while pth (and other userlevel thread implementations) can be
2048 considered to be "working" with Perl ithreads, keep in mind the
2049 possible non-preemptability of the underlying thread implementation.
2053 Stratus VOS is now supported using Perl's native build method
2054 (Configure). This is the recommended method to build Perl on
2055 VOS. The older methods, which build miniperl, are still
2056 available. See L<perlvos>. [561+]
2060 The Amdahl UTS UNIX mainframe platform is now supported. [561]
2064 WinCE is now supported. See L<perlce>.
2068 z/OS (formerly known as OS/390, formerly known as MVS OE) now has
2069 support for dynamic loading. This is not selected by default,
2070 however, you must specify -Dusedl in the arguments of Configure. [561]
2074 =head1 Selected Bug Fixes
2076 Numerous memory leaks and uninitialized memory accesses have been
2077 hunted down. Most importantly, anonymous subs used to leak quite
2084 The autouse pragma didn't work for Multi::Part::Function::Names.
2088 caller() could cause core dumps in certain situations. Carp was
2089 sometimes affected by this problem. In particular, caller() now
2090 returns a subroutine name of C<(unknown)> for subroutines that have
2091 been removed from the symbol table.
2095 chop(@list) in list context returned the characters chopped in
2096 reverse order. This has been reversed to be in the right order. [561]
2100 Configure no longer includes the DBM libraries (dbm, gdbm, db, ndbm)
2101 when building the Perl binary. The only exception to this is SunOS 4.x,
2102 which needs them. [561]
2106 The behaviour of non-decimal but numeric string constants such as
2107 "0x23" was platform-dependent: in some platforms that was seen as 35,
2108 in some as 0, in some as a floating point number (don't ask). This
2109 was caused by Perl's using the operating system libraries in a situation
2110 where the result of the string to number conversion is undefined: now
2111 Perl consistently handles such strings as zero in numeric contexts.
2115 The order of DESTROYs has been made more predictable.
2119 Perl 5.6.0 could emit spurious warnings about redefinition of
2120 dl_error() when statically building extensions into perl.
2121 This has been corrected. [561]
2125 L<dprofpp> -R didn't work.
2129 C<*foo{FORMAT}> now works.
2133 Infinity is now recognized as a number.
2137 UNIVERSAL::isa no longer caches methods incorrectly. (This broke
2138 the Tk extension with 5.6.0.) [561]
2142 Lexicals I: lexicals outside an eval "" weren't resolved
2143 correctly inside a subroutine definition inside the eval "" if they
2144 were not already referenced in the top level of the eval""ed code.
2148 Lexicals II: lexicals leaked at file scope into subroutines that
2149 were declared before the lexicals.
2153 Lexical warnings now propagating correctly between scopes
2154 and into C<eval "...">.
2158 C<use warnings qw(FATAL all)> did not work as intended. This has been
2163 warnings::enabled() now reports the state of $^W correctly if the caller
2164 isn't using lexical warnings. [561]
2168 Line renumbering with eval and C<#line> now works. [561]
2172 Fixed numerous memory leaks, especially in eval "".
2176 Localised tied variables no longer leak memory
2179 tie my %tied_hash => 'Tie::StdHash';
2183 # Used to leak memory every time local() was called;
2184 # in a loop, this added up.
2185 local($tied_hash{Foo}) = 1;
2189 Localised hash elements (and %ENV) are correctly unlocalised to not
2190 exist, if they didn't before they were localised.
2194 tie my %tied_hash => 'Tie::StdHash';
2198 # Nothing has set the FOO element so far
2200 { local $tied_hash{FOO} = 'Bar' }
2202 # This used to print, but not now.
2203 print "exists!\n" if exists $tied_hash{FOO};
2205 As a side effect of this fix, tied hash interfaces B<must> define
2206 the EXISTS and DELETE methods.
2210 mkdir() now ignores trailing slashes in the directory name,
2211 as mandated by POSIX.
2215 Some versions of glibc have a broken modfl(). This affects builds
2216 with C<-Duselongdouble>. This version of Perl detects this brokenness
2217 and has a workaround for it. The glibc release 2.2.2 is known to have
2218 fixed the modfl() bug.
2222 Modulus of unsigned numbers now works (4063328477 % 65535 used to
2223 return 27406, instead of 27047). [561]
2227 Some "not a number" warnings introduced in 5.6.0 eliminated to be
2228 more compatible with 5.005. Infinity is now recognised as a number. [561]
2232 Numeric conversions did not recognize changes in the string value
2233 properly in certain circumstances. [561]
2237 Attributes (such as :shared) didn't work with our().
2241 our() variables will not cause bogus "Variable will not stay shared"
2246 "our" variables of the same name declared in two sibling blocks
2247 resulted in bogus warnings about "redeclaration" of the variables.
2248 The problem has been corrected. [561]
2252 pack "Z" now correctly terminates the string with "\0".
2256 Fix password routines which in some shadow password platforms
2257 (e.g. HP-UX) caused getpwent() to return every other entry.
2261 The PERL5OPT environment variable (for passing command line arguments
2262 to Perl) didn't work for more than a single group of options. [561]
2266 PERL5OPT with embedded spaces didn't work.
2270 printf() no longer resets the numeric locale to "C".
2274 C<qw(a\\b)> now parses correctly as C<'a\\b'>: that is, as three
2275 characters, not four. [561]
2279 pos() did not return the correct value within s///ge in earlier
2280 versions. This is now handled correctly. [561]
2284 Printing quads (64-bit integers) with printf/sprintf now works
2285 without the q L ll prefixes (assuming you are on a quad-capable platform).
2289 Regular expressions on references and overloaded scalars now work. [561+]
2293 Right-hand side magic (GMAGIC) could in many cases such as string
2294 concatenation be invoked too many times.
2298 scalar() now forces scalar context even when used in void context.
2302 SOCKS support is now much more robust.
2306 sort() arguments are now compiled in the right wantarray context
2307 (they were accidentally using the context of the sort() itself).
2308 The comparison block is now run in scalar context, and the arguments
2309 to be sorted are always provided list context. [561]
2313 Changed the POSIX character class C<[[:space:]]> to include the (very
2314 rarely used) vertical tab character. Added a new POSIX-ish character
2315 class C<[[:blank:]]> which stands for horizontal whitespace
2316 (currently, the space and the tab).
2320 The tainting behaviour of sprintf() has been rationalized. It does
2321 not taint the result of floating point formats anymore, making the
2322 behaviour consistent with that of string interpolation. [561]
2326 Some cases of inconsistent taint propagation (such as within hash
2327 values) have been fixed.
2331 The RE engine found in Perl 5.6.0 accidentally pessimised certain kinds
2332 of simple pattern matches. These are now handled better. [561]
2336 Regular expression debug output (whether through C<use re 'debug'>
2337 or via C<-Dr>) now looks better. [561]
2341 Multi-line matches like C<"a\nxb\n" =~ /(?!\A)x/m> were flawed. The
2342 bug has been fixed. [561]
2346 Use of $& could trigger a core dump under some situations. This
2347 is now avoided. [561]
2351 The regular expression captured submatches ($1, $2, ...) are now
2352 more consistently unset if the match fails, instead of leaving false
2353 data lying around in them. [561]
2357 readline() on files opened in "slurp" mode could return an extra
2358 "" (blank line) at the end in certain situations. This has been
2363 Autovivification of symbolic references of special variables described
2364 in L<perlvar> (as in C<${$num}>) was accidentally disabled. This works
2369 Sys::Syslog ignored the C<LOG_AUTH> constant.
2373 $AUTOLOAD, sort(), lock(), and spawning subprocesses
2374 in multiple threads simultaneously are now thread-safe.
2378 Tie::Array's SPLICE method was broken.
2382 Allow a read-only string on the left-hand side of a non-modifying tr///.
2386 If C<STDERR> is tied, warnings caused by C<warn> and C<die> now
2387 correctly pass to it.
2391 Several Unicode fixes.
2397 BOMs (byte order marks) at the beginning of Perl files
2398 (scripts, modules) should now be transparently skipped.
2399 UTF-16 and UCS-2 encoded Perl files should now be read correctly.
2403 The character tables have been updated to Unicode 3.2.0.
2407 Comparing with utf8 data does not magically upgrade non-utf8 data
2408 into utf8. (This was a problem for example if you were mixing data
2409 from I/O and Unicode data: your output might have got magically encoded
2414 Generating illegal Unicode code points such as U+FFFE, or the UTF-16
2415 surrogates, now also generates an optional warning.
2419 C<IsAlnum>, C<IsAlpha>, and C<IsWord> now match titlecase.
2423 Concatenation with the C<.> operator or via variable interpolation,
2424 C<eq>, C<substr>, C<reverse>, C<quotemeta>, the C<x> operator,
2425 substitution with C<s///>, single-quoted UTF8, should now work.
2429 The C<tr///> operator now works. Note that the C<tr///CU>
2430 functionality has been removed (but see pack('U0', ...)).
2434 C<eval "v200"> now works.
2438 Perl 5.6.0 parsed m/\x{ab}/ incorrectly, leading to spurious warnings.
2439 This has been corrected. [561]
2443 Zero entries were missing from the Unicode classes such as C<IsDigit>.
2449 Large unsigned numbers (those above 2**31) could sometimes lose their
2450 unsignedness, causing bogus results in arithmetic operations. [561]
2454 The Perl parser has been stress tested using both random input and
2455 Markov chain input and the few found crashes and lockups have been
2460 =head2 Platform Specific Changes and Fixes
2468 Perl now works on post-4.0 BSD/OSes.
2474 Setting C<$0> now works (as much as possible; see L<perlvar> for details).
2480 Numerous updates; currently synchronised with Cygwin 1.3.10.
2484 Previously DYNIX/ptx had problems in its Configure probe for non-blocking I/O.
2490 EPOC now better supported. See README.epoc. [561]
2496 Perl now works on post-3.0 FreeBSDs.
2502 README.hpux updated; C<Configure -Duse64bitall> now works;
2503 now uses HP-UX malloc instead of Perl malloc.
2509 Numerous compilation flag and hint enhancements; accidental mixing
2510 of 32-bit and 64-bit libraries (a doomed attempt) made much harder.
2520 Long doubles should now work (see INSTALL). [561]
2524 Linux previously had problems related to sockaddrlen when using
2525 accept(), recvfrom() (in Perl: recv()), getpeername(), and
2534 Compilation of the standard Perl distribution in Mac OS Classic should
2535 now work if you have the Metrowerks development environment and the
2536 missing Mac-specific toolkit bits. Contact the macperl mailing list
2543 MPE/iX update after Perl 5.6.0. See README.mpeix. [561]
2547 NetBSD/threads: try installing the GNU pth (should be in the
2548 packages collection, or http://www.gnu.org/software/pth/),
2549 and Configure with -Duseithreads.
2555 Perl now works on NetBSD/sparc.
2561 Now works with usethreads (see INSTALL). [561]
2567 64-bitness using the Sun Workshop compiler now works.
2573 The native build method requires at least VOS Release 14.5.0
2574 and GNU C++/GNU Tools 2.0.1 or later. The Perl pack function
2575 now maps overflowed values to +infinity and underflowed values
2580 Tru64 (aka Digital UNIX, aka DEC OSF/1)
2582 The operating system version letter now recorded in $Config{osvers}.
2583 Allow compiling with gcc (previously explicitly forbidden). Compiling
2584 with gcc still not recommended because buggy code results, even with
2591 Fixed various alignment problems that lead into core dumps either
2592 during build or later; no longer dies on math errors at runtime;
2593 now using full quad integers (64 bits), previously was using
2594 only 46 bit integers for speed.
2600 See L</"Socket Extension Dynamic in VMS"> and L</"IEEE-format Floating Point
2601 Default on OpenVMS Alpha"> for important changes not otherwise listed here.
2603 chdir() now works better despite a CRT bug; now works with MULTIPLICITY
2604 (see INSTALL); now works with Perl's malloc.
2606 The tainting of C<%ENV> elements via C<keys> or C<values> was previously
2607 unimplemented. It now works as documented.
2609 The C<waitpid> emulation has been improved. The worst bug (now fixed)
2610 was that a pid of -1 would cause a wildcard search of all processes on
2613 POSIX-style signals are now emulated much better on VMS versions prior
2616 The C<system> function and backticks operator have improved
2617 functionality and better error handling. [561]
2619 File access tests now use current process privileges rather than the
2620 user's default privileges, which could sometimes result in a mismatch
2621 between reported access and actual access. This improvement is only
2622 available on VMS v6.0 and later.
2624 There is a new C<kill> implementation based on C<sys$sigprc> that allows
2625 older VMS systems (pre-7.0) to use C<kill> to send signals rather than
2626 simply force exit. This implementation also allows later systems to
2627 call C<kill> from within a signal handler.
2629 Iterative logical name translations are now limited to 10 iterations in
2630 imitation of SHOW LOGICAL and other OpenVMS facilities.
2640 Signal handling now works better than it used to. It is now implemented
2641 using a Windows message loop, and is therefore less prone to random
2646 fork() emulation is now more robust, but still continues to have a few
2647 esoteric bugs and caveats. See L<perlfork> for details. [561+]
2651 A failed (pseudo)fork now returns undef and sets errno to EAGAIN. [561]
2655 The following modules now work on Windows:
2657 ExtUtils::Embed [561]
2664 IO::File::new_tmpfile() is no longer limited to 32767 invocations
2669 Better chdir() return value for a non-existent directory.
2673 Compiling perl using the 64-bit Platform SDK tools is now supported.
2677 The Win32::SetChildShowWindow() builtin can be used to control the
2678 visibility of windows created by child processes. See L<Win32> for
2683 Non-blocking waits for child processes (or pseudo-processes) are
2684 supported via C<waitpid($pid, &POSIX::WNOHANG)>.
2688 The behavior of system() with multiple arguments has been rationalized.
2689 Each unquoted argument will be automatically quoted to protect whitespace,
2690 and any existing whitespace in the arguments will be preserved. This
2691 improves the portability of system(@args) by avoiding the need for
2692 Windows C<cmd> shell specific quoting in perl programs.
2694 Note that this means that some scripts that may have relied on earlier
2695 buggy behavior may no longer work correctly. For example,
2696 C<system("nmake /nologo", @args)> will now attempt to run the file
2697 C<nmake /nologo> and will fail when such a file isn't found.
2698 On the other hand, perl will now execute code such as
2699 C<system("c:/Program Files/MyApp/foo.exe", @args)> correctly.
2703 The perl header files no longer suppress common warnings from the
2704 Microsoft Visual C++ compiler. This means that additional warnings may
2705 now show up when compiling XS code.
2709 Borland C++ v5.5 is now a supported compiler that can build Perl.
2710 However, the generated binaries continue to be incompatible with those
2711 generated by the other supported compilers (GCC and Visual C++). [561]
2715 Duping socket handles with open(F, ">&MYSOCK") now works under Windows 9x.
2720 Current directory entries in %ENV are now correctly propagated to child
2725 New %ENV entries now propagate to subprocesses. [561]
2729 Win32::GetCwd() correctly returns C:\ instead of C: when at the drive root.
2730 Other bugs in chdir() and Cwd::cwd() have also been fixed. [561]
2734 The makefiles now default to the features enabled in ActiveState ActivePerl
2735 (a popular Win32 binary distribution). [561]
2739 HTML files will now be installed in c:\perl\html instead of
2740 c:\perl\lib\pod\html
2744 REG_EXPAND_SZ keys are now allowed in registry settings used by perl. [561]
2748 Can now send() from all threads, not just the first one. [561]
2752 ExtUtils::MakeMaker now uses $ENV{LIB} to search for libraries. [561]
2756 Less stack reserved per thread so that more threads can run
2757 concurrently. (Still 16M per thread.) [561]
2761 C<< File::Spec->tmpdir() >> now prefers C:/temp over /tmp
2762 (works better when perl is running as service).
2766 Better UNC path handling under ithreads. [561]
2770 wait(), waitpid(), and backticks now return the correct exit status
2771 under Windows 9x. [561]
2775 A socket handle leak in accept() has been fixed. [561]
2781 =head1 New or Changed Diagnostics
2787 The lexical warnings category "deprecated" is no longer a sub-category
2788 of the "syntax" category. It is now a top-level category in its own
2793 All regular expression compilation error messages are now hopefully
2794 easier to understand both because the error message now comes before
2795 the failed regex and because the point of failure is now clearly
2796 marked by a C<E<lt>-- HERE> marker.
2800 The various "opened only for", "on closed", "never opened" warnings
2801 drop the C<main::> prefix for filehandles in the C<main> package,
2802 for example C<STDIN> instead of C<main::STDIN>.
2806 The "Unrecognized escape" warning has been extended to include C<\8>,
2807 C<\9>, and C<\_>. There is no need to escape any of the C<\w> characters.
2811 Two new debugging options have been added: if you have compiled your
2812 Perl with debugging, you can use the -DT [561] and -DR options to trace
2813 tokenising and to add reference counts to displaying variables,
2818 Several debugger fixes: exit code now reflects the script exit code,
2819 condition C<"0"> now treated correctly, the C<d> command now checks
2820 line number, C<$.> no longer gets corrupted, and all debugger output
2821 now goes correctly to the socket if RemotePort is set. [561]
2825 The debugger (perl5db.pl) has been modified to present a more
2826 consistent commands interface, via (CommandSet=580). perl5db.t was
2827 also added to test the changes, and as a placeholder for further tests.
2833 The debugger has a new C<dumpDepth> option to control the maximum
2834 depth to which nested structures are dumped. The C<x> command has
2835 been extended so that C<x N EXPR> dumps out the value of I<EXPR> to a
2836 depth of at most I<N> levels.
2840 The debugger can now show lexical variables if you have the CPAN
2841 module PadWalker installed.
2845 If an attempt to use a (non-blessed) reference as an array index
2846 is made, a warning is given.
2850 C<push @a;> and C<unshift @a;> (with no values to push or unshift)
2851 now give a warning. This may be a problem for generated and evaled
2856 If you try to L<perlfunc/pack> a number less than 0 or larger than 255
2857 using the C<"C"> format you will get an optional warning. Similarly
2858 for the C<"c"> format and a number less than -128 or more than 127.
2862 Certain regex modifiers such as C<(?o)> make sense only if applied to
2863 the entire regex. You will get an optional warning if you try to do
2868 Using arrays or hashes as references (e.g. C<< %foo->{bar} >>
2869 has been deprecated for a while. Now you will get an optional warning.
2873 Using C<sort> in scalar context now issues an optional warning.
2874 This didn't do anything useful, as the sort was not performed.
2878 =head1 Changed Internals
2884 perlapi.pod (a companion to perlguts) now attempts to document the
2889 You can now build a really minimal perl called microperl.
2890 Building microperl does not require even running Configure;
2891 C<make -f Makefile.micro> should be enough. Beware: microperl makes
2892 many assumptions, some of which may be too bold; the resulting
2893 executable may crash or otherwise misbehave in wondrous ways.
2894 For careful hackers only.
2898 Added rsignal(), whichsig(), do_join(), op_clear, op_null,
2899 ptr_table_clear(), ptr_table_free(), sv_setref_uv(), and several UTF-8
2900 interfaces to the publicised API. For the full list of the available
2901 APIs see L<perlapi>.
2905 Made possible to propagate customised exceptions via croak()ing.
2909 Now xsubs can have attributes just like subs. (Well, at least the
2910 built-in attributes.)
2914 dTHR and djSP have been obsoleted; the former removed (because it's
2915 a no-op) and the latter replaced with dSP.
2919 PERL_OBJECT has been completely removed.
2923 The MAGIC constants (e.g. C<'P'>) have been macrofied
2924 (e.g. C<PERL_MAGIC_TIED>) for better source code readability
2925 and maintainability.
2929 The regex compiler now maintains a structure that identifies nodes in
2930 the compiled bytecode with the corresponding syntactic features of the
2931 original regex expression. The information is attached to the new
2932 C<offsets> member of the C<struct regexp>. See L<perldebguts> for more
2933 complete information.
2937 The C code has been made much more C<gcc -Wall> clean. Some warning
2938 messages still remain in some platforms, so if you are compiling with
2939 gcc you may see some warnings about dubious practices. The warnings
2940 are being worked on.
2944 F<perly.c>, F<sv.c>, and F<sv.h> have now been extensively commented.
2948 Documentation on how to use the Perl source repository has been added
2949 to F<Porting/repository.pod>.
2953 There are now several profiling make targets.
2957 =head1 Security Vulnerability Closed [561]
2959 (This change was already made in 5.7.0 but bears repeating here.)
2960 (5.7.0 came out before 5.6.1: the development branch 5.7 released
2961 sooner than the maintenance branch 5.6)
2963 A potential security vulnerability in the optional suidperl component
2964 of Perl was identified in August 2000. suidperl is neither built nor
2965 installed by default. As of November 2001 the only known vulnerable
2966 platform is Linux, most likely all Linux distributions. CERT and
2967 various vendors and distributors have been alerted about the vulnerability.
2968 See http://www.cpan.org/src/5.0/sperl-2000-08-05/sperl-2000-08-05.txt
2969 for more information.
2971 The problem was caused by Perl trying to report a suspected security
2972 exploit attempt using an external program, /bin/mail. On Linux
2973 platforms the /bin/mail program had an undocumented feature which
2974 when combined with suidperl gave access to a root shell, resulting in
2975 a serious compromise instead of reporting the exploit attempt. If you
2976 don't have /bin/mail, or if you have 'safe setuid scripts', or if
2977 suidperl is not installed, you are safe.
2979 The exploit attempt reporting feature has been completely removed from
2980 Perl 5.8.0 (and the maintenance release 5.6.1, and it was removed also
2981 from all the Perl 5.7 releases), so that particular vulnerability
2982 isn't there anymore. However, further security vulnerabilities are,
2983 unfortunately, always possible. The suidperl functionality is most
2984 probably going to be removed in Perl 5.10. In any case, suidperl
2985 should only be used by security experts who know exactly what they are
2986 doing and why they are using suidperl instead of some other solution
2987 such as sudo ( see http://www.courtesan.com/sudo/ ).
2991 Several new tests have been added, especially for the F<lib> and F<ext>
2992 subsections. There are now about 65 000 individual tests (spread over
2993 about 700 test scripts), in the regression suite (5.6.1 has about
2994 11700 tests, in 258 test scripts) Many of the new tests are of course
2995 introduced by the new modules, but still in general Perl is now more
2998 Because of the large number of tests, running the regression suite
2999 will take considerably longer time than it used to: expect the suite
3000 to take up to 4-5 times longer to run than in perl 5.6. On a really
3001 fast machine you can hope to finish the suite in about 6-8 minutes
3004 The tests are now reported in a different order than in earlier Perls.
3005 (This happens because the test scripts from under t/lib have been moved
3006 to be closer to the library/extension they are testing.)
3008 =head1 Known Problems
3016 If using the AIX native make command, instead of just "make" issue
3017 "make all". In some setups the former has been known to spuriously
3018 also try to run "make install". Alternatively, you may want to use
3023 In AIX 4.2, Perl extensions that use C++ functions that use statics
3024 may have problems in that the statics are not getting initialized.
3025 In newer AIX releases, this has been solved by linking Perl with
3026 the libC_r library, but unfortunately in AIX 4.2 the said library
3027 has an obscure bug where the various functions related to time
3028 (such as time() and gettimeofday()) return broken values, and
3029 therefore in AIX 4.2 Perl is not linked against libC_r.
3033 vac 5.0.0.0 May Produce Buggy Code For Perl
3035 The AIX C compiler vac version 5.0.0.0 may produce buggy code,
3036 resulting in a few random tests failing when run as part of "make
3037 test", but when the failing tests are run by hand, they succeed.
3038 We suggest upgrading to at least vac version 5.0.1.0, that has been
3039 known to compile Perl correctly. "lslpp -L|grep vac.C" will tell
3040 you the vac version. See README.aix.
3044 If building threaded Perl, you may get compilation warning from pp_sys.c:
3046 "pp_sys.c", line 4651.39: 1506-280 (W) Function argument assignment between types "unsigned char*" and "const void*" is not allowed.
3048 This is harmless; it is caused by the getnetbyaddr() and getnetbyaddr_r()
3049 having slightly different types for their first argument.
3053 =head2 Alpha systems with old gccs fail several tests
3055 If you see op/pack, op/pat, op/regexp, or ext/Storable tests failing
3056 in a Linux/alpha or *BSD/Alpha, it's probably time to upgrade your gcc.
3057 gccs prior to 2.95.3 are definitely not good enough, and gcc 3.1 may
3058 be even better. (RedHat Linux/alpha with gcc 3.1 reported no problems,
3059 as did Linux 2.4.18 with gcc 2.95.4.) (In Tru64, it is preferable to
3060 use the bundled C compiler.)
3064 Perl 5.8.0 doesn't build in AmigaOS. It broke at some point during
3065 the ithreads work and we could not find Amiga experts to unbreak the
3066 problems. Perl 5.6.1 still works for AmigaOS (as does the the 5.7.2
3067 development release).
3071 The following tests fail on 5.8.0 Perl in BeOS Personal 5.03:
3073 t/op/lfs............................FAILED at test 17
3074 t/op/magic..........................FAILED at test 24
3075 ext/POSIX/t/sigaction...............FAILED at test 13
3076 ext/POSIX/t/waitpid.................FAILED at test 1
3078 See L<perlbeos> (README.beos) for more details.
3080 =head2 Cygwin "unable to remap"
3082 For example when building the Tk extension for Cygwin,
3083 you may get an error message saying "unable to remap".
3084 This is known problem with Cygwin, and a workaround is
3085 detailed in here: http://sources.redhat.com/ml/cygwin/2001-12/msg00894.html
3087 =head2 ext/threads/t/libc
3089 If this test fails, it indicates that your libc (C library) is not
3090 threadsafe. This particular test stress tests the localtime() call to
3091 find out whether it is threadsafe. See L<perlthrtut> for more information.
3093 =head2 FreeBSD built with ithreads coredumps reading large directories
3095 This is a known bug in FreeBSD's readdir_r() (see L<perlfreebsd>
3096 (README.freebsd)), which hopefully will be fixed in FreeBSD 4.6.
3098 =head2 FreeBSD Failing locale Test 117 For ISO 8859-15 Locales
3100 The ISO 8859-15 locales may fail the locale test 117 in FreeBSD.
3101 This is caused by the characters \xFF (y with diaeresis) and \xBE
3102 (Y with diaeresis) not behaving correctly when being matched
3103 case-insensitively. Apparently this problem has been fixed in
3104 the latest FreeBSD releases.
3105 ( http://www.freebsd.org/cgi/query-pr.cgi?pr=34308 )
3107 =head2 IRIX fails ext/List/Util/t/shuffle.t
3109 IRIX with MIPSpro 7.3.1.3m compiler may fail the said List::Util test
3110 by dumping core. This seems to be a compiler error since if compiled
3111 with gcc no core dump ensues, and no failures on the said test on any
3114 =head2 Modifying $_ Inside for(..)
3118 works without complaint. It shouldn't. (You should be able to
3119 modify only lvalue elements inside the loops.) You can see the
3120 correct behaviour by replacing the 1..5 with 1, 2, 3, 4, 5.
3122 =head2 mod_perl 1.26 Doesn't Build With Threaded Perl
3124 Use mod_perl 1.27 or higher.
3126 =head2 lib/ftmp-security tests warn 'system possibly insecure'
3128 Don't panic. Read the 'make test' section of INSTALL instead.
3130 =head2 HP-UX lib/posix Subtest 9 Fails When LP64-Configured
3132 If perl is configured with -Duse64bitall, the successful result of the
3133 subtest 10 of lib/posix may arrive before the successful result of the
3134 subtest 9, which confuses the test harness so much that it thinks the
3137 =head2 Linux with glibc 2.2.5 fails t/op/int subtest #6 with -Duse64bitint
3139 This is a known bug in the glibc 2.2.5 with long long integers.
3140 ( http://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=65612 )
3142 =head2 Linux With Sfio Fails op/misc Test 48
3146 =head2 libwww-perl (LWP) fails base/date #51
3148 Use libwww-perl 5.65 or later.
3152 Please remember to set your environment variable LC_ALL to "C"
3153 (setenv LC_ALL C) before running "make test" to avoid a lot of
3154 warnings about the broken locales of Mac OS X.
3156 The following tests are known to fail in Mac OS X 10.1.5 because of
3157 buggy (old) implementations of Berkeley DB included in Mac OS X:
3159 Failed Test Stat Wstat Total Fail Failed List of Failed
3160 -------------------------------------------------------------------------
3161 ../ext/DB_File/t/db-btree.t 0 11 ?? ?? % ??
3162 ../ext/DB_File/t/db-recno.t 149 3 2.01% 61 63 65
3164 If you are building on a UFS partition, you will also probably see
3165 t/op/stat.t subtest #9 fail. This is caused by Darwin's UFS not
3166 supporting inode change time.
3168 Also the ext/POSIX/t/posix.t subtest #10 fails but it is skipped for
3169 now because the failure is Apple's fault, not Perl's (blocked signals
3172 If you Configure with ithreads, ext/threads/t/libc.t will fail. Again,
3173 this is not Perl's fault-- the libc of Mac OS X is not threadsafe
3174 (in this particular test, the localtime() call is found to be
3177 =head2 OS/2 Test Failures
3179 The following tests are known to fail on OS/2 (for clarity
3180 only the failures are shown, not the full error messages):
3182 t/io/utf8............................FAILED at test 19
3183 t/op/grent...........................FAILED at test 2
3184 t/op/pwent...........................FAILED at test 1
3185 t/lib/os2_base.......................FAILED at test 13
3186 t/lib/os2_process....................FAILED at test 10
3187 t/lib/os2_process_kid................FAILED at test 10
3188 t/lib/rx_cmprt.......................FAILED at test 16
3189 ext/DB_File/t/db-btree...............FAILED at test 0
3190 ext/DB_File/t/db-hash................FAILED at test 0
3191 ext/DB_File/t/db-recno...............FAILED at test 0
3192 lib/ExtUtils/t/basic.................FAILED at test 14
3193 lib/ExtUtils/t/Constant..............FAILED at test 4
3194 lib/Memoize/t/errors.................FAILED at test 4
3196 =head2 op/sprintf tests 91, 129, and 130
3198 The op/sprintf tests 91, 129, and 130 are known to fail on some platforms.
3199 Examples include any platform using sfio, and Compaq/Tandem's NonStop-UX.
3201 Test 91 is known to fail on QNX6 (nto), because C<sprintf '%e',0>
3202 incorrectly produces C<0.000000e+0> instead of C<0.000000e+00>.
3204 For tests 129 and 130, the failing platforms do not comply with
3205 the ANSI C Standard: lines 19ff on page 134 of ANSI X3.159 1989, to
3206 be exact. (They produce something other than "1" and "-1" when
3207 formatting 0.6 and -0.6 using the printf format "%.0f"; most often,
3208 they produce "0" and "-0".)
3212 In case you are still using Solaris 2.5 (aka SunOS 5.5), you may
3213 experience failures (the test core dumping) in lib/locale.t.
3214 The suggested cure is to upgrade your Solaris.
3216 =head2 Solaris x86 Fails Tests With -Duse64bitint
3218 The following tests are known to fail in Solaris x86 with Perl
3219 configured to use 64 bit integers:
3221 ext/Data/Dumper/t/dumper.............FAILED at test 268
3222 ext/Devel/Peek/Peek..................FAILED at test 7
3224 =head2 SUPER-UX (NEC SX)
3226 The following tests are known to fail on SUPER-UX:
3228 op/64bitint...........................FAILED tests 29-30, 32-33, 35-36
3229 op/arith..............................FAILED tests 128-130
3230 op/pack...............................FAILED tests 25-5625
3231 op/pow................................
3232 op/taint..............................# msgsnd failed
3233 ../ext/IO/lib/IO/t/io_poll............FAILED tests 3-4
3234 ../ext/IPC/SysV/ipcsysv...............FAILED tests 2, 5-6
3235 ../ext/IPC/SysV/t/msg.................FAILED tests 2, 4-6
3236 ../ext/Socket/socketpair..............FAILED tests 12
3237 ../lib/IPC/SysV.......................FAILED tests 2, 5-6
3238 ../lib/warnings.......................FAILED tests 115-116, 118-119
3240 The op/pack failure ("Cannot compress negative numbers at op/pack.t line 126")
3241 is serious but as of yet unsolved. It points at some problems with the
3242 signedness handling of the C compiler, as do the 64bitint, arith, and pow
3243 failures. Most of the rest point at problems with SysV IPC.
3245 =head2 PDL failing some tests
3247 Use PDL 2.3.4 or later.
3249 =head2 Term::ReadKey not working on Win32
3251 Use Term::ReadKey 2.20 or later.
3253 =head2 Failure of Thread (5.005-style) tests
3255 B<Note that support for 5.005-style threading is deprecated,
3256 experimental and practically unsupported. In 5.10, it is expected
3259 The following tests are known to fail due to fundamental problems in
3260 the 5.005 threading implementation. These are not new failures--Perl
3261 5.005_0x has the same bugs, but didn't have these tests.
3263 ../ext/B/t/xref.t 255 65280 14 12 85.71% 3-14
3264 ../ext/List/Util/t/first.t 255 65280 7 4 57.14% 2 5-7
3265 ../lib/English.t 2 512 54 2 3.70% 2-3
3266 ../lib/ExtUtils/t/basic.t 1 256 17 1 5.88% 14
3267 ../lib/FileCache.t 5 1 20.00% 5
3268 ../lib/Filter/Simple/t/data.t 6 3 50.00% 1-3
3269 ../lib/Filter/Simple/t/filter_onl 9 3 33.33% 1-2 5
3270 ../lib/Tie/File/t/31_autodefer.t 255 65280 65 32 49.23% 34-65
3271 ../lib/autouse.t 10 1 10.00% 4
3272 op/flip.t 15 1 6.67% 15
3274 These failures are unlikely to get fixed as 5.005-style threads
3275 are considered fundamentally broken. (Basically what happens is that
3276 competing threads can corrupt shared global state.)
3278 =head2 Timing problems
3280 The following tests may fail intermittently because of timing
3281 problems, for example if the system is heavily loaded.
3284 ext/Time/HiRes/HiRes.t
3286 lib/Memoize/t/expmod_t.t
3287 lib/Memoize/t/speed.t
3289 In case of failure please try running them manually, for example
3291 ./perl -Ilib ext/Time/HiRes/HiRes.t
3293 =head2 Unicode in package/class and subroutine names does not work
3295 One can have Unicode in identifier names, but not in package/class or
3296 subroutine names. While some limited functionality towards this does
3297 exist as of Perl 5.8.0, that is more accidental than designed; use of
3298 Unicode for the said purposes is unsupported.
3300 One reason of this unfinishedness is its (currently) inherent
3301 unportability: since both package names and subroutine names may
3302 need to be mapped to file and directory names, the Unicode capability
3303 of the filesystem becomes important-- and there unfortunately aren't
3312 During Configure, the test
3314 Guessing which symbols your C compiler and preprocessor define...
3316 will probably fail with error messages like
3318 CC-20 cc: ERROR File = try.c, Line = 3
3319 The identifier "bad" is undefined.
3321 bad switch yylook 79bad switch yylook 79bad switch yylook 79bad switch yylook 79#ifdef A29K
3324 CC-65 cc: ERROR File = try.c, Line = 3
3325 A semicolon is expected at this point.
3327 This is caused by a bug in the awk utility of UNICOS/mk. You can ignore
3328 the error, but it does cause a slight problem: you cannot fully
3329 benefit from the h2ph utility (see L<h2ph>) that can be used to
3330 convert C headers to Perl libraries, mainly used to be able to access
3331 from Perl the constants defined using C preprocessor, cpp. Because of
3332 the above error, parts of the converted headers will be invisible.
3333 Luckily, these days the need for h2ph is rare.
3337 If building Perl with interpreter threads (ithreads), the
3338 getgrent(), getgrnam(), and getgrgid() functions cannot return the
3339 list of the group members due to a bug in the multithreaded support of
3340 UNICOS/mk. What this means is that in list context the functions will
3341 return only three values, not four.
3347 There are a few known test failures, see L<perluts> (README.uts).
3349 =head2 VOS (Stratus)
3351 When Perl is built using the native build process on VOS Release
3352 14.5.0 and GNU C++/GNU Tools 2.0.1, all attempted tests either
3353 pass or result in TODO (ignored) failures.
3357 There should be no reported test failures with a default configuration,
3358 though there are a number of tests marked TODO that point to areas
3359 needing further debugging and/or porting work.
3363 In multi-CPU boxes, there are some problems with the I/O buffering:
3364 some output may appear twice.
3366 =head2 XML::Parser not working
3368 Use XML::Parser 2.31 or later.
3370 =head2 z/OS (OS/390)
3372 z/OS has rather many test failures but the situation is actually
3373 better than it was in 5.6.0; it's just that so many new modules and
3374 tests have been added.
3376 Failed Test Stat Wstat Total Fail Failed List of Failed
3377 ---------------------------------------------------------------------------
3378 ../ext/Data/Dumper/t/dumper.t 357 8 2.24% 311 314 325 327
3380 ../ext/IO/lib/IO/t/io_unix.t 5 4 80.00% 2-5
3381 ../ext/Storable/t/downgrade.t 12 3072 169 12 7.10% 14-15 46-47 78-79
3383 ../lib/ExtUtils/t/Constant.t 121 30976 48 48 100.00% 1-48
3384 ../lib/ExtUtils/t/Embed.t 9 9 100.00% 1-9
3385 op/pat.t 910 7 0.77% 665 776 785 832-
3387 op/sprintf.t 224 3 1.34% 98 100 136
3388 op/tr.t 97 5 5.15% 63 71-74
3389 uni/fold.t 780 6 0.77% 61 169 196 661
3392 The failures in dumper.t and downgrade.t are problems in the tests,
3393 those in io_unix and sprintf are problems in the USS (UDP sockets
3394 and printf formats). The pat, tr, and fold failures are genuine Perl
3395 problems caused by EBCDIC (and in the pat and fold cases, combining
3396 that with Unicode). The Constant and Embed are probably problems
3397 in the tests (since they test Perl's ability to build extensions,
3398 and that seems to be working reasonably well.)
3400 =head2 Localising Tied Arrays and Hashes Is Broken
3404 doesn't work as one would expect: the old value is restored
3405 incorrectly. This will be changed in a future release, but we don't
3406 know yet what the new semantics will exactly be. In any case, the
3407 change will break existing code that relies on the current
3408 (ill-defined) semantics, so just avoid doing this in general.
3410 =head2 Self-tying Problems
3412 Self-tying of arrays and hashes is broken in rather deep and
3413 hard-to-fix ways. As a stop-gap measure to avoid people from getting
3414 frustrated at the mysterious results (core dumps, most often), it is
3415 forbidden for now (you will get a fatal error even from an attempt).
3417 A change to self-tying of globs has caused them to be recursively
3418 referenced (see: L<perlobj/"Two-Phased Garbage Collection">). You
3419 will now need an explicit untie to destroy a self-tied glob. This
3420 behaviour may be fixed at a later date.
3422 Self-tying of scalars and IO thingies works.
3424 =head2 Tied/Magical Array/Hash Elements Do Not Autovivify
3426 For normal arrays C<$foo = \$bar[1]> will assign C<undef> to
3427 C<$bar[1]> (assuming that it didn't exist before), but for
3428 tied/magical arrays and hashes such autovivification does not happen
3429 because there is currently no way to catch the reference creation.
3430 The same problem affects slicing over non-existent indices/keys of
3431 a tied/magical array/hash.
3433 =head2 Building Extensions Can Fail Because Of Largefiles
3435 Some extensions like mod_perl are known to have issues with
3436 `largefiles', a change brought by Perl 5.6.0 in which file offsets
3437 default to 64 bits wide, where supported. Modules may fail to compile
3438 at all, or they may compile and work incorrectly. Currently, there
3439 is no good solution for the problem, but Configure now provides
3440 appropriate non-largefile ccflags, ldflags, libswanted, and libs
3441 in the %Config hash (e.g., $Config{ccflags_nolargefiles}) so the
3442 extensions that are having problems can try configuring themselves
3443 without the largefileness. This is admittedly not a clean solution,
3444 and the solution may not even work at all. One potential failure is
3445 whether one can (or, if one can, whether it's a good idea to) link
3446 together at all binaries with different ideas about file offsets;
3447 all this is platform-dependent.
3449 =head2 Unicode Support on EBCDIC Still Spotty
3451 Though mostly working, Unicode support still has problem spots on
3452 EBCDIC platforms. One such known spot are the C<\p{}> and C<\P{}>
3453 regular expression constructs for code points less than 256: the
3454 C<pP> are testing for Unicode code points, not knowing about EBCDIC.
3456 =head2 The Compiler Suite Is Still Very Experimental
3458 The compiler suite is slowly getting better but it continues to be
3459 highly experimental. Use in production environments is discouraged.
3461 =head2 The Long Double Support Is Still Experimental
3463 The ability to configure Perl's numbers to use "long doubles",
3464 floating point numbers of hopefully better accuracy, is still
3465 experimental. The implementations of long doubles are not yet
3466 widespread and the existing implementations are not quite mature
3467 or standardised, therefore trying to support them is a rare
3468 and moving target. The gain of more precision may also be offset
3469 by slowdown in computations (more bits to move around, and the
3470 operations are more likely to be executed by less optimised
3473 =head2 Seen In Perl 5.7 But Gone Now
3475 C<Time::Piece> (previously known as C<Time::Object>) was removed
3476 because it was felt that it didn't have enough value in it to be a
3477 core module. It is still a useful module, though, and is available
3480 Perl 5.8 unfortunately does not build anymore on AmigaOS; this broke
3481 accidentally at some point. Since there are not that many Amiga
3482 developers available, we could not get this fixed and tested in time
3483 for 5.8.0. Perl 5.6.1 still works for AmigaOS (as does the the 5.7.2
3484 development release).
3486 =head1 Reporting Bugs
3488 If you find what you think is a bug, you might check the articles
3489 recently posted to the comp.lang.perl.misc newsgroup and the perl
3490 bug database at http://bugs.perl.org/ . There may also be
3491 information at http://www.perl.com/ , the Perl Home Page.
3493 If you believe you have an unreported bug, please run the B<perlbug>
3494 program included with your release. Be sure to trim your bug down
3495 to a tiny but sufficient test case. Your bug report, along with the
3496 output of C<perl -V>, will be sent off to perlbug@perl.org to be
3497 analysed by the Perl porting team.
3501 The F<Changes> file for exhaustive details on what changed.
3503 The F<INSTALL> file for how to build Perl.
3505 The F<README> file for general stuff.
3507 The F<Artistic> and F<Copying> files for copyright information.
3511 Written by Jarkko Hietaniemi <F<jhi@iki.fi>>.