3 perl5120delta - what is new for perl v5.12.0
7 This document describes differences between the 5.10.0 release and
10 Many of the bug fixes in 5.12.0 are already included in the 5.10.1
13 You can see the list of those changes in the 5.10.1 release notes (L<perl5101delta>).
16 =head1 Core Enhancements
18 =head2 New C<package NAME VERSION> syntax
20 This new syntax allows a module author to set the $VERSION of a namespace
21 when the namespace is declared with 'package'. It eliminates the need
22 for C<our $VERSION = ...> and similar constructs. E.g.
24 package Foo::Bar 1.23;
25 # $Foo::Bar::VERSION == 1.23
27 There are several advantages to this:
33 C<$VERSION> is parsed in exactly the same way as C<use NAME VERSION>
37 C<$VERSION> is set at compile time
41 C<$VERSION> is a version object that provides proper overloading of
42 comparison operators so comparing C<$VERSION> to decimal (1.23) or
43 dotted-decimal (v1.2.3) version numbers works correctly.
47 Eliminates C<$VERSION = ...> and C<eval $VERSION> clutter
51 As it requires VERSION to be a numeric literal or v-string
52 literal, it can be statically parsed by toolchain modules
53 without C<eval> the way MM-E<gt>parse_version does for C<$VERSION = ...>
57 It does not break old code with only C<package NAME>, but code that uses
58 C<package NAME VERSION> will need to be restricted to perl 5.12.0 or newer
59 This is analogous to the change to C<open> from two-args to three-args.
60 Users requiring the latest Perl will benefit, and perhaps after several
61 years, it will become a standard practice.
65 However, C<package NAME VERSION> requires a new, 'strict' version
66 number format. See L<"Version number formats"> for details.
69 =head2 The C<...> operator
71 A new operator, C<...>, nicknamed the Yada Yada operator, has been added.
72 It is intended to mark placeholder code that is not yet implemented.
73 See L<perlop/"Yada Yada Operator">. (chromatic)
75 =head2 Implicit strictures
77 Using the C<use VERSION> syntax with a version number greater or equal
78 to 5.11.0 will lexically enable strictures just like C<use strict>
79 would do (in addition to enabling features.) The following:
88 =head2 Unicode improvements
90 Perl 5.12 comes with Unicode 5.2, the latest version available to
91 us at the time of release. This version of Unicode was released in
92 October 2009. See L<http://www.unicode.org/versions/Unicode5.2.0> for
93 further details about what's changed in this version of the standard.
94 See L<perlunicode> for instructions on installing and using other versions
97 Additionally, Perl's developers have significantly improved Perl's Unicode
98 implementation. For full details, see L</Unicode overhaul> below.
100 =head2 Y2038 compliance
102 Perl's core time-related functions are now Y2038 compliant. (It may not mean much to you, but your kids will love it!)
104 =head2 qr overloading
106 It is now possible to overload the C<qr//> operator, that is,
107 conversion to regexp, like it was already possible to overload
108 conversion to boolean, string or number of objects. It is invoked when
109 an object appears on the right hand side of the C<=~> operator or when
110 it is interpolated into a regexp. See L<overload>.
112 =head2 Pluggable keywords
114 Extension modules can now cleanly hook into the Perl parser to define
115 new kinds of keyword-headed expression and compound statement. The
116 syntax following the keyword is defined entirely by the extension. This
117 allow a completely non-Perl sublanguage to be parsed inline, with the
118 correct ops cleanly generated.
120 See L<perlapi/PL_keyword_plugin> for the mechanism. The Perl core
121 source distribution also includes a new module
122 L<XS::APItest::KeywordRPN>, which implements reverse Polish notation
123 arithmetic via pluggable keywords. This module is mainly used for test
124 purposes, and is not normally installed, but also serves as an example
125 of how to use the new mechanism.
127 Perl's developers consider this feature to be experimental. We may remove
128 it or change it in a backwards-incompatible way in Perl 5.14.
130 =head2 APIs for more internals
132 The lowest layers of the lexer and parts of the pad system now have C
133 APIs available to XS extensions. These are necessary to support proper
134 use of pluggable keywords, but have other uses too. The new APIs are
135 experimental, and only cover a small proportion of what would be
136 necessary to take full advantage of the core's facilities in these
137 areas. It is intended that the Perl 5.13 development cycle will see the
138 addition of a full range of clean, supported interfaces.
140 Perl's developers consider this feature to be experimental. We may remove
141 it or change it in a backwards-incompatible way in Perl 5.14.
143 =head2 Overridable function lookup
145 Where an extension module hooks the creation of rv2cv ops to modify the
146 subroutine lookup process, this now works correctly for bareword
147 subroutine calls. This means that prototypes on subroutines referenced
148 this way will be processed correctly. (Previously bareword subroutine
149 names were initially looked up, for parsing purposes, by an unhookable
150 mechanism, so extensions could only properly influence subroutine names
151 that appeared with an C<&> sigil.)
153 =head2 A proper interface for pluggable Method Resolution Orders
155 As of Perl 5.12.0 there is a new interface for plugging and using method
156 resolution orders other than the default linear depth first search.
157 The C3 method resolution order added in 5.10.0 has been re-implemented as
158 a plugin, without changing its Perl-space interface. See L<perlmroapi> for
163 =head2 C<\N> experimental regex escape
165 Perl now supports C<\N>, a new regex escape which you can think of as
166 the inverse of C<\n>. It will match any character that is not a newline,
167 independently from the presence or absence of the single line match
168 modifier C</s>. It is not usable within a character class. C<\N{3}>
169 means to match 3 non-newlines; C<\N{5,}> means to match at least 5.
170 C<\N{NAME}> still means the character or sequence named C<NAME>, but
171 C<NAME> no longer can be things like C<3>, or C<5,>.
173 This will break a L<custom charnames translator|charnames/CUSTOM
174 TRANSLATORS> which allows numbers for character names, as C<\N{3}> will
175 now mean to match 3 non-newline characters, and not the character whose
176 name is C<3>. (No name defined by the Unicode standard is a number,
177 so only custom translators might be affected.)
179 Perl's developers are somewhat concerned about possible user confusion
180 with the existing C<\N{...}> construct which matches characters by their
181 Unicode name. Consequently, this feature is experimental. We may remove
182 it or change it in a backwards-incompatible way in Perl 5.14.
184 =head2 DTrace support
186 Perl now has some support for DTrace. See "DTrace support" in F<INSTALL>.
188 =head2 Support for C<configure_requires> in CPAN module metadata
190 Both C<CPAN> and C<CPANPLUS> now support the C<configure_requires> keyword
191 in the F<META.yml> metadata file included in most recent CPAN distributions.
192 This allows distribution authors to specify configuration prerequisites that
193 must be installed before running F<Makefile.PL> or F<Build.PL>.
195 See the documentation for C<ExtUtils::MakeMaker> or C<Module::Build> for more
196 on how to specify C<configure_requires> when creating a distribution for CPAN.
198 =head2 C<each> is now more flexible
200 The C<each> function can now operate on arrays.
202 =head2 C<when> as a statement modifier
204 C<when> is now allowed to be used as a statement modifier.
206 =head2 C<$,> flexibility
208 The variable C<$,> may now be tied.
210 =head2 // in when clauses
212 // now behaves like || in when clauses
214 =head2 Enabling warnings from your shell environment
216 You can now set C<-W> from the C<PERL5OPT> environment variable
218 =head2 C<delete local>
220 C<delete local> now allows you to locally delete a hash entry.
222 =head2 New support for Abstract namespace sockets
224 Abstract namespace sockets are Linux-specific socket type that live in
225 AF_UNIX family, slightly abusing it to be able to use arbitrary
226 character arrays as addresses: They start with nul byte and are not
227 terminated by nul byte, but with the length passed to the socket()
230 =head2 32-bit limit on substr arguments removed
232 The 32-bit limit on C<substr> arguments has now been removed. The full range
233 of the system's signed and unsigned integers is now available for the C<pos>
234 and C<len> arguments.
236 =head1 Potentially Incompatible Changes
238 =head2 Deprecations warn by default
240 Perl now defaults to issuing a warning if a deprecated language feature
243 To disable this feature in a given lexical scope, you should use C<no
244 warnings 'deprecated';> For information about which language features
245 are deprecated and explanations of various deprecation warnings, please
246 see L<perldiag.pod>. See L</Deprecations> below for the list of features
247 and modules Perl's developers have deprecated as part of this release.
249 =head2 Version number formats
251 Acceptable version number formats have been formalized into "strict" and
252 "lax" rules. C<package NAME VERSION> takes a strict version number.
253 C<UNIVERSAL::VERSION> and the L<version> object constructors take lax
254 version numbers. Providing an invalid version will result in a fatal
255 error. The version argument in C<use NAME VERSION> is first parsed as a
256 numeric literal or v-string and then passed to C<UNIVERSAL::VERSION>
257 (and must then pass the "lax" format test).
259 These formats are documented fully in the L<version> module. To a first
260 approximation, a "strict" version number is a positive decimal number
261 (integer or decimal-fraction) without exponentiation or else a
262 dotted-decimal v-string with a leading 'v' character and at least three
263 components. A "lax" version number allows v-strings with fewer than
264 three components or without a leading 'v'. Under "lax" rules, both
265 decimal and dotted-decimal versions may have a trailing "alpha"
266 component separated by an underscore character after a fractional or
267 dotted-decimal component.
269 The L<version> module adds C<version::is_strict> and C<version::is_lax>
270 functions to check a scalar against these rules.
272 =head2 @INC reorganization
274 In C<@INC>, C<ARCHLIB> and C<PRIVLIB> now occur after after the current
275 version's C<site_perl> and C<vendor_perl>. Modules installed into
276 C<site_perl> and C<vendor_perl> will now be loaded in preference to
277 those installed in C<ARCHLIB> and C<PRIVLIB>.
279 =head2 Switch statement changes
281 The C<given>/C<when> switch statement handles complex statements better
282 than Perl 5.10.0 did (These enhancements are also available in
283 5.10.1 and subsequent 5.10 releases.) There are two new cases where
284 C<when> now interprets its argument as a boolean, instead of an
285 expression to be used in a smart match:
289 =item flip-flop operators
291 The C<..> and C<...> flip-flop operators are now evaluated in boolean
292 context, following their usual semantics; see L<perlop/"Range Operators">.
294 Note that, as in perl 5.10.0, C<when (1..10)> will not work to test
295 whether a given value is an integer between 1 and 10; you should use
296 C<when ([1..10])> instead (note the array reference).
298 However, contrary to 5.10.0, evaluating the flip-flop operators in boolean
299 context ensures it can now be useful in a C<when()>, notably for
300 implementing bistable conditions, like in:
302 when (/^=begin/ .. /^=end/) {
306 =item defined-or operator
308 A compound expression involving the defined-or operator, as in
309 C<when (expr1 // expr2)>, will be treated as boolean if the first
310 expression is boolean. (This just extends the existing rule that applies
311 to the regular or operator, as in C<when (expr1 || expr2)>.)
315 =head2 Smart match changes
317 Since Perl 5.10.0, Perl's developers have made a number of changes to
318 the smart match operator. These, of course, also alter the behaviour
319 of the switch statements where smart matching is implicitly used.
320 These changes were also made for the 5.10.1 release, and will remain in
321 subsequent 5.10 releases.
323 =head3 Changes to type-based dispatch
325 The smart match operator C<~~> is no longer commutative. The behaviour of
326 a smart match now depends primarily on the type of its right hand
327 argument. Moreover, its semantics have been adjusted for greater
328 consistency or usefulness in several cases. While the general backwards
329 compatibility is maintained, several changes must be noted:
335 Code references with an empty prototype are no longer treated specially.
336 They are passed an argument like the other code references (even if they
337 choose to ignore it).
341 C<%hash ~~ sub {}> and C<@array ~~ sub {}> now test that the subroutine
342 returns a true value for each key of the hash (or element of the
343 array), instead of passing the whole hash or array as a reference to
348 Due to the commutativity breakage, code references are no longer
349 treated specially when appearing on the left of the C<~~> operator,
350 but like any vulgar scalar.
354 C<undef ~~ %hash> is always false (since C<undef> can't be a key in a
355 hash). No implicit conversion to C<""> is done (as was the case in perl
360 C<$scalar ~~ @array> now always distributes the smart match across the
361 elements of the array. It's true if one element in @array verifies
362 C<$scalar ~~ $element>. This is a generalization of the old behaviour
363 that tested whether the array contained the scalar.
367 The full dispatch table for the smart match operator is given in
368 L<perlsyn/"Smart matching in detail">.
370 =head3 Smart match and overloading
372 According to the rule of dispatch based on the rightmost argument type,
373 when an object overloading C<~~> appears on the right side of the
374 operator, the overload routine will always be called (with a 3rd argument
375 set to a true value, see L<overload>.) However, when the object will
376 appear on the left, the overload routine will be called only when the
377 rightmost argument is a simple scalar. This way, distributivity of smart
378 match across arrays is not broken, as well as the other behaviours with
379 complex types (coderefs, hashes, regexes). Thus, writers of overloading
380 routines for smart match mostly need to worry only with comparing
381 against a scalar, and possibly with stringification overloading; the
382 other common cases will be automatically handled consistently.
384 C<~~> will now refuse to work on objects that do not overload it (in order
385 to avoid relying on the object's underlying structure). (However, if the
386 object overloads the stringification or the numification operators, and
387 if overload fallback is active, it will be used instead, as usual.)
389 =head2 Other potentially incompatible changes
395 The definitions of a number of Unicode properties have changed to match
396 those of the current Unicode standard. These are listed above under
397 L</Unicode overhaul>. This change may break code that expects the old definitions.
401 The boolkeys op has moved to the group of hash ops. This breaks binary
406 Filehandles are now always blessed into C<IO::File>.
408 The previous behaviour was to bless Filehandles into L<FileHandle>
409 (an empty proxy class) if it was loaded into memory and otherwise
410 to bless them into C<IO::Handle>.
414 The semantics of C<use feature :5.10*> have changed slightly.
415 See L<"Modules and Pragmata"> for more information.
419 Perl's developers now use git, rather than Perforce. This should be
420 a purely internal change only relevant to people actively working on
421 the core. However, you may see minor difference in perl as a consequence
422 of the change. For example in some of details of the output of C<perl
423 -V>. See L<perlrepository> for more information.
427 As part of the C<Test::Harness> 2.x to 3.x upgrade, the experimental
428 C<Test::Harness::Straps> module has been removed.
429 See L</"Modules and Pragmata"> for more details.
433 As part of the C<ExtUtils::MakeMaker> upgrade, the
434 C<ExtUtils::MakeMaker::bytes> and C<ExtUtils::MakeMaker::vmsish> modules
435 have been removed from this distribution.
439 C<Module::CoreList> no longer contains the C<%:patchlevel> hash.
444 C<length undef> now returns undef.
448 Unsupported private C API functions are now declared "static" to prevent
449 leakage to Perl's public API.
453 To support the bootstrapping process, F<miniperl> no longer builds with
454 UTF-8 support in the regexp engine.
456 This allows a build to complete with PERL_UNICODE set and a UTF-8 locale.
457 Without this there's a bootstrapping problem, as miniperl can't load the UTF-8
458 components of the regexp engine, because they're not yet built.
462 F<miniperl>'s @INC is now restricted to just C<-I...>, the split of
463 C<$ENV{PERL5LIB}>, and "C<.>"
467 A space or a newline is now required after a C<"#line XXX"> directive.
471 Tied filehandles now have an additional method EOF which provides the EOF type
475 To better match all other flow control statements, C<foreach> may no
476 longer be used as an attribute.
483 From time to time, Perl's developers find it necessary to deprecate
484 features or modules we've previously shipped as part of the core
485 distribution. We are well aware of the pain and frustration that a
486 backwards-incompatible change to Perl can cause for developers building
487 or maintaining software in Perl. You can be sure that when we deprecate
488 a functionality or syntax, it isn't a choice we make lightly. Sometimes,
489 we choose to deprecate functionality or syntax because it was found to
490 be poorly designed or implemented. Sometimes, this is because they're
491 holding back other features or causing performance problems. Sometimes,
492 the reasons are more complex. Wherever possible, we try to keep deprecated
493 functionality available to developers in its previous form for at least
494 one major release. So long as a deprecated feature isn't actively
495 disrupting our ability to maintain and extend Perl, we'll try to leave
496 it in place as long as possible.
498 The following items are now deprecated:
504 C<suidperl> is no longer part of Perl. It used to provide a mechanism to
505 emulate setuid permission bits on systems that don't support it properly.
508 =item Use of C<:=> to mean an empty attribute list
510 An accident of Perl's parser meant that these constructions were all
517 with the C<:> being treated as the start of an attribute list, which
518 ends before the C<=>. As whitespace is not significant here, all are
519 parsed as an empty attribute list, hence all the above are equivalent
520 to, and better written as
524 because no attribute processing is done for an empty list.
526 As is, this meant that C<:=> cannot be used as a new token, without
527 silently changing the meaning of existing code. Hence that particular
528 form is now deprecated, and will become a syntax error. If it is
529 absolutely necessary to have empty attribute lists (for example,
530 because of a code generator) then avoid the warning by adding a space
533 =item C<< UNIVERSAL->import() >>
535 The method C<< UNIVERSAL->import() >> is now deprecated. Attempting to
536 pass import arguments to a C<use UNIVERSAL> statement will result in a
540 =item Use of "goto" to jump into a construct
542 Using C<goto> to jump from an outer scope into an inner scope is now
543 deprecated. This rare use case was causing problems in the
544 implementation of scopes.
546 =item Custom character names in \N{name} that don't look like names
548 In C<\N{I<name>}>, I<name> can be just about anything. The standard Unicode
549 names have a very limited domain, but a custom name translator could create
550 names that are, for example, made up entirely of punctuation symbols. It is
551 now deprecated to make names that don't begin with an alphabetic character, and
552 aren't alphanumeric or contain other than a very few other characters,
553 namely spaces, dashes, parentheses and colons. Because of the added meaning of
554 C<\N> (See L</C<\N> experimental regex escape>), names that look like curly
555 brace -enclosed quantifiers won't work. For example, C<\N{3,4}> now means to
556 match 3 to 4 non-newlines; before a custom name C<3,4> could have been created.
558 =item Deprecated Modules
560 The following modules will be removed from the core distribution in a future
561 release, and should be installed from CPAN instead. Distributions on CPAN
562 which require these should add them to their prerequisites. The core versions
563 of these modules warnings will issue a deprecation warning.
565 If you ship a packaged version of Perl, either alone or as part of a larger
566 system, then you should carefully consider the reprecussions of core module
567 deprecations. You may want to consider shipping your default build of
568 Perl with packages for some or all deprecated modules which install into
569 C<vendor> or C<site> perl library directories. This will inhibit the
570 deprecation warnings.
572 Alternatively, you may want to consider patching F<lib/deprecate.pm>
573 to provide deprecation warnings specific to your packaging system or
574 distribution of Perl, consistent with how your packaging system or
575 distribution manages a staged transition from a release where the
576 installation of a single package provides the given functionality, to a later
577 release where the system administrator needs to know to install multiple
578 packages to get that same functionality.
584 =item L<Pod::Plainer>
590 Switch is buggy and should be avoided. You may find Perl's new
591 C<given>/C<when> feature a suitable replacement. See L<perlsyn/"Switch
592 statements"> for more information.
596 =item Assignment to $[
598 =item Use of the attribute :locked on subroutines
600 =item Use of "locked" with the attributes pragma
602 =item Use of "unique" with the attributes pragma
606 C<Perl_pmflag> is no longer part of Perl's public API. Calling it now
607 generates a deprecation warning, and it will be removed in a future
608 release. Although listed as part of the API, it was never documented,
609 and only ever used in F<toke.c>, and prior to 5.10, F<regcomp.c>. In
610 core, it has been replaced by a static function.
612 =item Numerous Perl 4-era libraries
614 F<termcap.pl>, F<tainted.pl>, F<stat.pl>, F<shellwords.pl>, F<pwd.pl>,
615 F<open3.pl>, F<open2.pl>, F<newgetopt.pl>, F<look.pl>, F<find.pl>,
616 F<finddepth.pl>, F<importenv.pl>, F<hostname.pl>, F<getopts.pl>,
617 F<getopt.pl>, F<getcwd.pl>, F<flush.pl>, F<fastcwd.pl>, F<exceptions.pl>,
618 F<ctime.pl>, F<complete.pl>, F<cacheout.pl>, F<bigrat.pl>, F<bigint.pl>,
619 F<bigfloat.pl>, F<assert.pl>, F<abbrev.pl>, F<dotsh.pl>, and
620 F<timelocal.pl> are all now deprecated. Using them will incur a warning.
625 =head1 Unicode overhaul
627 Perl's developers have made a concerted effort to update Perl to be in
628 sync with the latest Unicode standard. Changes for this include:
630 Perl can now handle every Unicode character property. New documentation,
631 L<perluniprops>, lists all available non-Unihan character properties. By
632 default, perl does not expose Unihan, deprecated or Unicode-internal
633 properties. See below for more details on these; there is also a section
634 in the pod listing them, and explaining why they are not exposed.
636 Perl now fully supports the Unicode compound-style of using C<=> and C<:>
637 in writing regular expressions: C<\p{property=value}> and
638 C<\p{property:value}> (both of which mean the same thing).
640 Perl now fully supports the Unicode loose matching rules for text
641 between the braces in C<\p{...}> constructs. In addition, Perl allows
642 underscores between digits of numbers.
644 Perl now accepts all the Unicode-defined synonyms for properties and property values.
646 C<qr/\X/>, which matches a Unicode logical character, has been expanded to work
647 better with various Asian languages. It now is defined as an I<extended
648 grapheme cluster>. (See L<http://www.unicode.org/reports/tr29/>).
649 Anything matched previously and that made sense will continue to be
650 accepted. Additionally:
656 C<\X> will not break apart a C<S<CR LF>> sequence.
660 C<\X> will now match a sequence which includes the C<ZWJ> and C<ZWNJ> characters.
664 C<\X> will now always match at least one character, including an initial mark.
665 Marks generally come after a base character, but it is possible in Unicode to
666 have them in isolation, and C<\X> will now handle that case, for example at the
667 beginning of a line, or after a C<ZWSP>. And this is the part where C<\X>
668 doesn't match the things that it used to that don't make sense. Formerly, for
669 example, you could have the nonsensical case of an accented LF.
673 C<\X> will now match a (Korean) Hangul syllable sequence, and the Thai and Lao
678 Otherwise, this change should be transparent for the non-affected
681 C<\p{...}> matches using the Canonical_Combining_Class property were
682 completely broken in previous releases of Perl. They should now work
685 Before Perl 5.12, the Unicode C<Decomposition_Type=Compat> property
686 and a Perl extension had the same name, which led to neither matching
687 all the correct values (with more than 100 mistakes in one, and several
688 thousand in the other). The Perl extension has now been renamed to be
689 C<Decomposition_Type=Noncanonical> (short: C<dt=noncanon>). It has the
690 same meaning as was previously intended, namely the union of all the
691 non-canonical Decomposition types, with Unicode C<Compat> being just
694 C<\p{Decomposition_Type=Canonical}> now includes the Hangul syllables.
696 C<\p{Uppercase}> and C<\p{Lowercase}> now work as the Unicode standard
697 says they should. This means they each match a few more characters than
700 C<\p{Cntrl}> now matches the same characters as C<\p{Control}>. This
701 means it no longer will match Private Use (gc=co), Surrogates (gc=cs),
702 nor Format (gc=cf) code points. The Format code points represent the
703 biggest possible problem. All but 36 of them are either officially
704 deprecated or strongly discouraged from being used. Of those 36, likely
705 the most widely used are the soft hyphen (U+00AD), and BOM, ZWSP, ZWNJ,
706 WJ, and similar characters, plus bidirectional controls.
708 C<\p{Alpha}> now matches the same characters as C<\p{Alphabetic}>. Before
709 5.12, Perl's definition definition included a number of things that aren't
710 really alpha (all marks) while omitting many that were. The definitions
711 of C<\p{Alnum}> and C<\p{Word}> depend on Alpha's definition and have
714 C<\p{Word}> no longer incorrectly matches non-word characters such
717 C<\p{Print}> no longer matches the line control characters: Tab, LF,
718 CR, FF, VT, and NEL. This brings it in line with standards and the
721 C<\p{XDigit}> now matches the same characters as C<\p{Hex_Digit}>. This
722 means that in addition to the characters it currently matches,
723 C<[A-Fa-f0-9]>, it will also match the 22 fullwidth equivalents, for
724 example U+FF10: FULLWIDTH DIGIT ZERO.
726 The Numeric type property has been extended to include the Unihan
729 There is a new Perl extension, the 'Present_In', or simply 'In',
730 property. This is an extension of the Unicode Age property, but
731 C<\p{In=5.0}> matches any code point whose usage has been determined
732 I<as of> Unicode version 5.0. The C<\p{Age=5.0}> only matches code points
733 added in I<precisely> version 5.0.
735 A number of properties now have the correct values for unassigned
736 code points. The affected properties are Bidi_Class, East_Asian_Width,
737 Joining_Type, Decomposition_Type, Hangul_Syllable_Type, Numeric_Type,
740 The Default_Ignorable_Code_Point, ID_Continue, and ID_Start properties
741 are now up to date with current Unicode definitions.
743 Earlier versions of Perl erroneously exposed certain properties that
744 are supposed to be Unicode internal-only. Use of these in regular
745 expressions will now generate, if enabled, a deprecation warning message.
746 The properties are: Other_Alphabetic, Other_Default_Ignorable_Code_Point,
747 Other_Grapheme_Extend, Other_ID_Continue, Other_ID_Start, Other_Lowercase,
748 Other_Math, and Other_Uppercase.
750 It is now possible to change which Unicode properties Perl understands
751 on a per-installation basis. As mentioned above, certain properties
752 are turned off by default. These include all the Unihan properties
753 (which should be accessible via the CPAN module Unicode::Unihan) and any
754 deprecated or Unicode internal-only property that Perl has never exposed.
756 The generated files in the C<lib/unicore/To> directory are now more
757 clearly marked as being stable, directly usable by applications. New hash
758 entries in them give the format of the normal entries, which allows for
759 easier machine parsing. Perl can generate files in this directory for
760 any property, though most are suppressed. You can find instructions
761 for changing which are written in L<perluniprops>.
765 =head1 Modules and Pragmata
767 =head2 New Modules and Pragmata
773 C<autodie> is a new lexically-scoped alternative for the C<Fatal> module.
774 The bundled version is 2.06_01. Note that in this release, using a string
775 eval when C<autodie> is in effect can cause the autodie behaviour to leak
776 into the surrounding scope. See L<autodie/"BUGS"> for more details.
778 Version 2.06_01 has been added to the Perl core.
780 =item C<Compress::Raw::Bzip2>
782 Version 2.024 has been added to the Perl core.
786 C<overloading> allows you to lexically disable or enable overloading
787 for some or all operations. (Yuval Kogman)
789 Version 0.001 has been added to the Perl core.
793 C<parent> establishes an ISA relationship with base classes at compile
794 time. It provides the key feature of C<base> without further unwanted
797 Version 0.223 has been added to the Perl core.
799 =item C<Parse::CPAN::Meta>
801 Version 1.40 has been added to the Perl core.
805 Version 1.03 has been added to the Perl core.
809 Version 2.4 has been added to the Perl core.
811 =item C<XS::APItest::KeywordRPN>
813 Version 0.003 has been added to the Perl core.
817 =head2 Updated Pragmata
823 Upgraded from version 2.13 to 2.15.
827 Upgraded from version 0.22 to 0.23.
831 C<charnames> now contains the Unicode F<NameAliases.txt> database file.
832 This has the effect of adding some extra C<\N> character names that
833 formerly wouldn't have been recognised; for example, C<"\N{LATIN CAPITAL
836 Upgraded from version 1.06 to 1.07.
840 Upgraded from version 1.13 to 1.20.
844 C<diagnostics> now supports %.0f formatting internally.
846 C<diagnostics> no longer suppresses C<Use of uninitialized value in range
847 (or flip)> warnings. [perl #71204]
849 Upgraded from version 1.17 to 1.19.
853 In C<feature>, the meaning of the C<:5.10> and C<:5.10.X> feature bundles has
854 changed slightly. The last component, if any (i.e. C<X>) is simply ignored.
855 This is predicated on the assumption that new features will not, in
856 general, be added to maintenance releases. So C<:5.10> and C<:5.10.X>
857 have identical effect. This is a change to the behaviour documented for
860 C<feature> now includes the C<unicode_strings> feature:
862 use feature "unicode_strings";
864 This pragma turns on Unicode semantics for the case-changing operations
865 (C<uc>, C<lc>, C<ucfirst>, C<lcfirst>) on strings that don't have the
866 internal UTF-8 flag set, but that contain single-byte characters between
869 Upgraded from version 1.11 to 1.16.
873 C<less> now includes the C<stash_name> method to allow subclasses of
874 C<less> to pick where in %^H to store their stash.
876 Upgraded from version 0.02 to 0.03.
880 Upgraded from version 0.5565 to 0.62.
884 C<mro> is now implemented as an XS extension. The documented interface has not
885 changed. Code relying on the implementation detail that some C<mro::>
886 methods happened to be available at all times gets to "keep both pieces".
888 Upgraded from version 1.00 to 1.02.
892 C<overload> now allow overloading of 'qr'.
894 Upgraded from version 1.06 to 1.10.
898 Upgraded from version 1.67 to 1.75.
900 =item C<threads::shared>
902 Upgraded from version 1.14 to 1.32.
906 C<version> now has support for L</Version number formats> as described earlier
907 in this document and in its own documentation.
909 Upgraded from version 0.74 to 0.82.
913 C<warnings> has a new C<warnings::fatal_enabled()> function. It also
914 includes a new C<illegalproto> warning category. See also L</New or
915 Changed Diagnostics> for this change.
917 Upgraded from version 1.06 to 1.09.
921 =head2 Updated Modules
925 =item C<Archive::Extract>
927 Upgraded from version 0.24 to 0.38.
929 =item C<Archive::Tar>
931 Upgraded from version 1.38 to 1.54.
933 =item C<Attribute::Handlers>
935 Upgraded from version 0.79 to 0.87.
939 Upgraded from version 5.63 to 5.70.
943 Upgraded from version 0.74 to 0.78.
947 Upgraded from version 1.05 to 1.12.
951 Upgraded from version 0.83 to 0.94.
955 Upgraded from version 1.09 to 1.11_01.
959 Upgraded from version 3.29 to 3.48.
963 Upgraded from version 0.33 to 0.36.
965 NOTE: C<Class::ISA> is deprecated and may be removed from a future version of Perl.
967 =item C<Compress::Raw::Zlib>
969 Upgraded from version 2.008 to 2.024.
973 Upgraded from version 1.9205 to 1.94_56.
977 Upgraded from version 0.84 to 0.90.
979 =item C<CPANPLUS::Dist::Build>
981 Upgraded from version 0.06_02 to 0.46.
983 =item C<Data::Dumper>
985 Upgraded from version 2.121_14 to 2.125.
989 Upgraded from version 1.816_1 to 1.820.
991 =item C<Devel::PPPort>
993 Upgraded from version 3.13 to 3.19.
997 Upgraded from version 1.15 to 1.16.
1001 Upgraded from version 2.36_01 to 2.39.
1003 =item C<Digest::SHA>
1005 Upgraded from version 5.45 to 5.47.
1009 Upgraded from version 2.23 to 2.39.
1013 Upgraded from version 5.62 to 5.64_01.
1015 =item C<ExtUtils::CBuilder>
1017 Upgraded from version 0.21 to 0.27.
1019 =item C<ExtUtils::Command>
1021 Upgraded from version 1.13 to 1.16.
1023 =item C<ExtUtils::Constant>
1025 Upgraded from version 0.2 to 0.22.
1027 =item C<ExtUtils::Install>
1029 Upgraded from version 1.44 to 1.55.
1031 =item C<ExtUtils::MakeMaker>
1033 Upgraded from version 6.42 to 6.56.
1035 =item C<ExtUtils::Manifest>
1037 Upgraded from version 1.51_01 to 1.57.
1039 =item C<ExtUtils::ParseXS>
1041 Upgraded from version 2.18_02 to 2.21.
1043 =item C<File::Fetch>
1045 Upgraded from version 0.14 to 0.24.
1049 Upgraded from version 2.04 to 2.08_01.
1053 Upgraded from version 0.18 to 0.22.
1055 =item C<Filter::Simple>
1057 Upgraded from version 0.82 to 0.84.
1059 =item C<Filter::Util::Call>
1061 Upgraded from version 1.07 to 1.08.
1063 =item C<Getopt::Long>
1065 Upgraded from version 2.37 to 2.38.
1069 Upgraded from version 1.23_01 to 1.25_02.
1073 Upgraded from version 1.07 to 1.10.
1077 Upgraded from version 0.40_1 to 0.54.
1081 Upgraded from version 1.05 to 2.01.
1083 =item C<Locale::Maketext>
1085 Upgraded from version 1.12 to 1.14.
1087 =item C<Locale::Maketext::Simple>
1089 Upgraded from version 0.18 to 0.21.
1091 =item C<Log::Message>
1093 Upgraded from version 0.01 to 0.02.
1095 =item C<Log::Message::Simple>
1097 Upgraded from version 0.04 to 0.06.
1099 =item C<Math::BigInt>
1101 Upgraded from version 1.88 to 1.89_01.
1103 =item C<Math::BigInt::FastCalc>
1105 Upgraded from version 0.16 to 0.19.
1107 =item C<Math::BigRat>
1109 Upgraded from version 0.21 to 0.24.
1111 =item C<Math::Complex>
1113 Upgraded from version 1.37 to 1.56.
1117 Upgraded from version 1.01_02 to 1.01_03.
1119 =item C<MIME::Base64>
1121 Upgraded from version 3.07_01 to 3.08.
1123 =item C<Module::Build>
1125 Upgraded from version 0.2808_01 to 0.3603.
1127 =item C<Module::CoreList>
1129 Upgraded from version 2.12 to 2.27.
1131 =item C<Module::Load>
1133 Upgraded from version 0.12 to 0.16.
1135 =item C<Module::Load::Conditional>
1137 Upgraded from version 0.22 to 0.34.
1139 =item C<Module::Loaded>
1141 Upgraded from version 0.01 to 0.06.
1143 =item C<Module::Pluggable>
1145 Upgraded from version 3.6 to 3.9.
1149 Upgraded from version 2.33 to 2.36.
1153 Upgraded from version 0.60_01 to 0.64.
1155 =item C<Object::Accessor>
1157 Upgraded from version 0.32 to 0.36.
1159 =item C<Package::Constants>
1161 Upgraded from version 0.01 to 0.02.
1165 Upgraded from version 1.04 to 1.06.
1167 =item C<Pod::Parser>
1169 Upgraded from version 1.35 to 1.37.
1171 =item C<Pod::Perldoc>
1173 Upgraded from version 3.14_02 to 3.15_02.
1175 =item C<Pod::Plainer>
1177 Upgraded from version 0.01 to 1.02.
1179 NOTE: C<Pod::Plainer> is deprecated and may be removed from a future version of Perl.
1181 =item C<Pod::Simple>
1183 Upgraded from version 3.05 to 3.13.
1187 Upgraded from version 2.12 to 2.22.
1191 Upgraded from version 1.11 to 1.17.
1195 Upgraded from version 2.18 to 2.22.
1199 Upgraded from version 2.13 to 2.16.
1201 NOTE: C<Switch> is deprecated and may be removed from a future version of Perl.
1203 =item C<Sys::Syslog>
1205 Upgraded from version 0.22 to 0.27.
1207 =item C<Term::ANSIColor>
1209 Upgraded from version 1.12 to 2.02.
1213 Upgraded from version 0.18 to 0.20.
1217 Upgraded from version 1.25 to 1.25_02.
1219 =item C<Test::Harness>
1221 Upgraded from version 2.64 to 3.17.
1223 =item C<Test::Simple>
1225 Upgraded from version 0.72 to 0.94.
1227 =item C<Text::Balanced>
1229 Upgraded from version 2.0.0 to 2.02.
1231 =item C<Text::ParseWords>
1233 Upgraded from version 3.26 to 3.27.
1235 =item C<Text::Soundex>
1237 Upgraded from version 3.03 to 3.03_01.
1239 =item C<Thread::Queue>
1241 Upgraded from version 2.00 to 2.11.
1243 =item C<Thread::Semaphore>
1245 Upgraded from version 2.01 to 2.09.
1247 =item C<Tie::RefHash>
1249 Upgraded from version 1.37 to 1.38.
1251 =item C<Time::HiRes>
1253 Upgraded from version 1.9711 to 1.9719.
1255 =item C<Time::Local>
1257 Upgraded from version 1.18 to 1.1901_01.
1259 =item C<Time::Piece>
1261 Upgraded from version 1.12 to 1.15.
1263 =item C<Unicode::Collate>
1265 Upgraded from version 0.52 to 0.52_01.
1267 =item C<Unicode::Normalize>
1269 Upgraded from version 1.02 to 1.03.
1273 Upgraded from version 0.34 to 0.39.
1275 =item C<Win32API::File>
1277 Upgraded from version 0.1001_01 to 0.1101.
1281 Upgraded from version 0.08 to 0.10.
1285 =head2 Removed Modules and Pragmata
1291 Removed from the Perl core. Prior version was 1.02.
1293 =item C<CPAN::API::HOWTO>
1295 Removed from the Perl core. Prior version was 'undef'.
1297 =item C<CPAN::DeferedCode>
1299 Removed from the Perl core. Prior version was 5.50.
1301 =item C<CPANPLUS::inc>
1303 Removed from the Perl core. Prior version was 'undef'.
1307 Removed from the Perl core. Prior version was 1.03.
1309 =item C<ExtUtils::MakeMaker::bytes>
1311 Removed from the Perl core. Prior version was 6.42.
1313 =item C<ExtUtils::MakeMaker::vmsish>
1315 Removed from the Perl core. Prior version was 6.42.
1319 Removed from the Perl core. Prior version was 2.3.
1321 =item C<Test::Harness::Assert>
1323 Removed from the Perl core. Prior version was 0.02.
1325 =item C<Test::Harness::Iterator>
1327 Removed from the Perl core. Prior version was 0.02.
1329 =item C<Test::Harness::Point>
1331 Removed from the Perl core. Prior version was 0.01.
1333 =item C<Test::Harness::Results>
1335 Removed from the Perl core. Prior version was 0.01.
1337 =item C<Test::Harness::Straps>
1339 Removed from the Perl core. Prior version was 0.26_01.
1341 =item C<Test::Harness::Util>
1343 Removed from the Perl core. Prior version was 0.01.
1347 Removed from the Perl core. Prior version was 1.1.
1351 =head2 Deprecated Modules and Pragmata
1353 See L</Deprecated Modules> above.
1356 =head1 Documentation
1358 =head2 New Documentation
1364 L<perlhaiku> contains instructions on how to build perl for the Haiku platform.
1368 L<perlmroapi> describes the new interface for pluggable Method Resolution Orders.
1372 L<perlperf>, by Richard Foley, provides an introduction to the use of
1373 performance and optimization techniques which can be used with particular
1374 reference to perl programs.
1378 L<perlrepository> describes how to access the perl source using the I<git> version
1383 L<perlpolicy> extends the "Social contract about contributed modules" into
1384 the beginnings of a document on Perl porting policies.
1388 =head2 Changes to Existing Documentation
1396 The various large F<Changes*> files (which listed every change made to perl
1397 over the last 18 years) have been removed, and replaced by a small file,
1398 also called F<Changes>, which just explains how that same information may
1399 be extracted from the git version control system.
1403 F<Porting/patching.pod> has been deleted, as it mainly described
1404 interacting with the old Perforce-based repository, which is now obsolete.
1405 Information still relevant has been moved to L<perlrepository>.
1410 The syntax C<unless (EXPR) BLOCK else BLOCK> is now documented as valid, as
1411 is the syntax C<unless (EXPR) BLOCK elsif (EXPR) BLOCK ... else BLOCK>,
1412 although actually using the latter may not be the best idea for the
1413 readability of your source code.
1418 Documented -X overloading.
1422 Documented that C<when()> treats specially most of the filetest operators
1426 Documented C<when> as a syntax modifier.
1430 Eliminated "Old Perl threads tutorial", which described 5005 threads.
1432 F<pod/perlthrtut.pod> is the same material reworked for ithreads.
1436 Correct previous documentation: v-strings are not deprecated
1438 With version objects, we need them to use MODULE VERSION syntax. This
1439 patch removes the deprecation notice.
1443 Security contact information is now part of L<perlsec>.
1447 A significant fraction of the core documentation has been updated to clarify
1448 the behavior of Perl's Unicode handling.
1450 Much of the remaining core documentation has been reviewed and edited
1451 for clarity, consistent use of language, and to fix the spelling of Tom
1452 Christiansen's name.
1456 The Pod specification (L<perlpodspec>) has been updated to bring the
1457 specification in line with modern usage already supported by most Pod
1458 systems. A parameter string may now follow the format name in a
1459 "begin/end" region. Links to URIs with a text description are now
1460 allowed. The usage of C<LE<lt>"section"E<gt>> has been marked as
1465 L<if.pm|if> has been documented in L<perlfunc/use> as a means to get
1466 conditional loading of modules despite the implicit BEGIN block around
1471 The documentation for C<$1> in perlvar.pod has been clarified.
1475 C<\N{U+I<wide hex char>}> is now documented.
1479 =head1 Selected Performance Enhancements
1485 A new internal cache means that C<isa()> will often be faster.
1489 The implementation of C<C3> Method Resolution Order has been optimised -
1490 linearisation for classes with single inheritance is 40% faster. Performance
1491 for multiple inheritance is unchanged.
1495 Under C<use locale>, the locale-relevant information is now cached on
1496 read-only values, such as the list returned by C<keys %hash>. This makes
1497 operations such as C<sort keys %hash> in the scope of C<use locale> much
1502 Empty C<DESTROY> methods are no longer called.
1506 C<Perl_sv_utf8_upgrade()> is now faster.
1510 C<keys> on empty hash is now faster.
1514 C<if (%foo)> has been optimized to be faster than C<if (keys %foo)>.
1518 The string repetition operator (C<$str x $num>) is now several times faster
1519 when C<$str> has length one or C<$num> is large.
1523 Reversing an array to itself (as in C<@a = reverse @a>) in void context
1524 now happens in-place and is several orders of magnitude faster than it
1525 used to be. It will also preserve non-existent elements whenever
1526 possible, i.e. for non magical arrays or tied arrays with C<EXISTS> and
1531 =head1 Installation and Configuration Improvements
1537 L<perlapi>, L<perlintern>, L<perlmodlib> and L<perltoc> are now all
1538 generated at build time, rather than being shipped as part of the release.
1542 If C<vendorlib> and C<vendorarch> are the same, then they are only added to
1547 C<$Config{usedevel}> and the C-level C<PERL_USE_DEVEL> are now defined if
1548 perl is built with C<-Dusedevel>.
1552 F<Configure> will enable use of C<-fstack-protector>, to provide protection
1553 against stack-smashing attacks, if the compiler supports it.
1557 F<Configure> will now determine the correct prototypes for re-entrant
1558 functions and for C<gconvert> if you are using a C++ compiler rather
1563 On Unix, if you build from a tree containing a git repository, the
1564 configuration process will note the commit hash you have checked out, for
1565 display in the output of C<perl -v> and C<perl -V>. Unpushed local commits
1566 are automatically added to the list of local patches displayed by
1571 Perl now supports SystemTap's C<dtrace> compatibility layer and an
1572 issue with linking C<miniperl> has been fixed in the process.
1576 perldoc now uses C<less -R> instead of C<less> for improved behaviour
1577 in the face of C<groff>'s new usage of ANSI escape codes.
1582 C<perl -V> now reports use of the compile-time options C<USE_PERL_ATOF> and
1583 C<USE_ATTRIBUTES_FOR_PERLIO>.
1587 As part of the flattening of F<ext>, all extensions on all platforms are
1588 built by F<make_ext.pl>. This replaces the Unix-specific
1589 F<ext/util/make_ext>, VMS-specific F<make_ext.com> and Win32-specific
1590 F<win32/buildext.pl>.
1594 =head1 Internal Changes
1596 Each release of Perl sees numerous internal changes which shouldn't
1597 affect day to day usage but may still be notable for developers working
1598 with Perl's source code.
1604 The J.R.R. Tolkien quotes at the head of C source file have been checked and
1605 proper citations added, thanks to a patch from Tom Christiansen.
1609 The internal structure of the dual-life modules traditionally found in
1610 the F<lib/> and F<ext/> directories y in the perl source has changed
1611 significantly. Where possible, dual-lifed modules have been extracted
1612 from F<lib/> and F<ext/>.
1614 Dual-lifed modules maintained by Perl's developers as part of the Perl
1615 core now live in F<dist/>. Dual-lifed modules maintained primarily on
1616 CPAN now live in F<cpan/>. When reporting a bug in a module located
1617 under F<cpan/>, please send your bug report directly to the module's
1618 bug tracker or author, rather than Perl's bug tracker.
1622 C<\N{...}> now compiles better, always forces UTF-8 internal representation
1624 Perl's developers have fixed several problems with the recognition of C<\N{...}>
1625 constructs. As part of this, perl will store any scalar or regex containing
1626 C<\N{I<name>}> or C<\N{U+I<wide hex char>}> in its definition in
1627 UTF-8 format. (This was true previously for all occurences of C<\N{I<name>}>
1628 that did not use a custom translator, but now it's always true.)
1632 Perl_magic_setmglob now knows about globs, fixing RT #71254.
1636 C<SVt_RV> no longer exists. RVs are now stored in IVs.
1640 REGEXPs are now first class.
1644 C<Perl_vcroak()> now accepts a null first argument. In addition, a full audit
1645 was made of the "not NULL" compiler annotations, and those for several
1646 other internal functions were corrected.
1650 New macros C<dSAVEDERRNO>, C<dSAVE_ERRNO>, C<SAVE_ERRNO>, C<RESTORE_ERRNO>
1651 have been added to formalise the temporary saving of the C<errno>
1656 The function C<Perl_sv_insert_flags> has been added to augment
1661 The function C<Perl_newSV_type(type)> has been added, equivalent to
1662 C<Perl_newSV()> followed by C<Perl_sv_upgrade(type)>.
1666 The function C<Perl_newSVpvn_flags()> has been added, equivalent to
1667 C<Perl_newSVpvn()> and then performing the action relevant to the flag.
1669 Two flag bits are currently supported.
1675 C<SVf_UTF8> will call C<SvUTF8_on()> for you. (Note that this does not convert an
1676 sequence of ISO 8859-1 characters to UTF-8). A wrapper, C<newSVpvn_utf8()>
1677 is available for this.
1681 C<SVs_TEMP> now calls C<Perl_sv_2mortal()> on the new SV.
1685 There is also a wrapper that takes constant strings, C<newSVpvs_flags()>.
1689 The function C<Perl_croak_xs_usage> has been added as a wrapper to
1694 Perl now exports the functions C<PerlIO_find_layer> and C<PerlIO_list_alloc>.
1698 C<PL_na> has been exterminated from the core code, replaced by local STRLEN
1699 temporaries, or C<*_nolen()> calls. Either approach is faster than C<PL_na>,
1700 which is a pointer dereference into the interpreter structure under ithreads,
1701 and a global variable otherwise.
1705 C<Perl_mg_free()> used to leave freed memory accessible via C<SvMAGIC()> on
1706 the scalar. It now updates the linked list to remove each piece of magic
1711 Under ithreads, the regex in C<PL_reg_curpm> is now reference counted. This
1712 eliminates a lot of hackish workarounds to cope with it not being reference
1717 C<Perl_mg_magical()> would sometimes incorrectly turn on C<SvRMAGICAL()>.
1718 This has been fixed.
1722 The I<public> IV and NV flags are now not set if the string value has
1723 trailing "garbage". This behaviour is consistent with not setting the
1724 public IV or NV flags if the value is out of range for the type.
1728 Uses of C<Nullav>, C<Nullcv>, C<Nullhv>, C<Nullop>, C<Nullsv> etc have been
1729 replaced by C<NULL> in the core code, and non-dual-life modules, as C<NULL>
1730 is clearer to those unfamiliar with the core code.
1734 A macro C<MUTABLE_PTR(p)> has been added, which on (non-pedantic) gcc will
1735 not cast away C<const>, returning a C<void *>. Macros C<MUTABLE_SV(av)>,
1736 C<MUTABLE_SV(cv)> etc build on this, casting to C<AV *> etc without
1737 casting away C<const>. This allows proper compile-time auditing of
1738 C<const> correctness in the core, and helped picked up some errors (now
1743 Macros C<mPUSHs()> and C<mXPUSHs()> have been added, for pushing SVs on the
1744 stack and mortalizing them.
1748 Use of the private structure C<mro_meta> has changed slightly. Nothing
1749 outside the core should be accessing this directly anyway.
1753 A new tool, F<Porting/expand-macro.pl> has been added, that allows you
1754 to view how a C preprocessor macro would be expanded when compiled.
1755 This is handy when trying to decode the macro hell that is the perl
1762 =head2 Testing improvements
1766 =item Parallel tests
1768 The core distribution can now run its regression tests in parallel on
1769 Unix-like platforms. Instead of running C<make test>, set C<TEST_JOBS> in
1770 your environment to the number of tests to run in parallel, and run
1771 C<make test_harness>. On a Bourne-like shell, this can be done as
1773 TEST_JOBS=3 make test_harness # Run 3 tests in parallel
1775 An environment variable is used, rather than parallel make itself, because
1776 L<TAP::Harness> needs to be able to schedule individual non-conflicting test
1777 scripts itself, and there is no standard interface to C<make> utilities to
1778 interact with their job schedulers.
1780 Note that currently some test scripts may fail when run in parallel (most
1781 notably C<ext/IO/t/io_dir.t>). If necessary run just the failing scripts
1782 again sequentially and see if the failures go away.
1784 =item Test harness flexibility
1786 It's now possible to override C<PERL5OPT> and friends in F<t/TEST>
1790 Several tests that have the potential to hang forever if they fail now
1791 incorporate a "watchdog" functionality that will kill them after a timeout,
1792 which helps ensure that C<make test> and C<make test_harness> run to
1793 completion automatically. (Jerry Hedden).
1800 Perl's developers have added a number of new tests to the core.
1801 In addition to the items listed below, many modules updated from CPAN
1802 incorporate new tests.
1808 Significant cleanups to core tests to ensure that language and
1809 interpreter features are not used before they're tested.
1813 C<make test_porting> now runs a number of important pre-commit checks
1814 which might be of use to anyone working on the Perl core.
1818 F<t/porting/podcheck.t> automatically checks the well-formedness of
1819 POD found in all .pl, .pm and .pod files in the F<MANIFEST>, other than in
1820 dual-lifed modules which are primarily maintained outside the Perl core.
1824 F<t/porting/manifest.t> now tests that all files listed in MANIFEST are present.
1828 F<t/op/while_readdir.t> tests that a bare readdir in while loop sets $_.
1832 F<t/comp/retainedlines.t> checks that the debugger can retain source lines from C<eval>.
1836 F<t/io/perlio_fail.t> checks that bad layers fail.
1840 F<t/io/perlio_leaks.t> checks that PerlIO layers are not leaking.
1844 F<t/io/perlio_open.t> checks that certain special forms of open work.
1848 F<t/io/perlio.t> includes general PerlIO tests.
1852 F<t/io/pvbm.t> checks that there is no unexpected interaction between the internal types
1853 C<PVBM> and C<PVGV>.
1857 F<t/mro/package_aliases.t> checks that mro works properly in the presence of aliased packages.
1861 F<t/op/dbm.t> tests C<dbmopen> and C<dbmclose>.
1865 F<t/op/index_thr.t> tests the interaction of C<index> and threads.
1869 F<t/op/pat_thr.t> tests the interaction of esoteric patterns and threads.
1873 F<t/op/qr_gc.t> tests that C<qr> doesn't leak.
1877 F<t/op/reg_email_thr.t> tests the interaction of regex recursion and threads.
1881 F<t/op/regexp_qr_embed_thr.t> tests the interaction of patterns with embedded C<qr//> and threads.
1885 F<t/op/regexp_unicode_prop.t> tests Unicode properties in regular expressions.
1889 F<t/op/regexp_unicode_prop_thr.t> tests the interaction of Unicode properties and threads.
1893 F<t/op/reg_nc_tie.t> tests the tied methods of C<Tie::Hash::NamedCapture>.
1897 F<t/op/reg_posixcc.t> checks that POSIX character classes behave consistently.
1903 checks that exportable C<re> functions in F<universal.c> work.
1907 F<t/op/setpgrpstack.t> checks that C<setpgrp> works.
1911 F<t/op/substr_thr.t> tests the interaction of C<substr> and threads.
1915 F<t/op/upgrade.t> checks that upgrading and assigning scalars works.
1919 F<t/uni/lex_utf8.t> checks that Unicode in the lexer works.
1923 F<t/uni/tie.t> checks that Unicode and C<tie> work.
1927 F<t/comp/final_line_num.t> tests whether line numbers are correct at EOF
1931 F<t/comp/form_scope.t> tests format scoping.
1935 F<t/comp/line_debug.t> tests whether C<< @{"_<$file"} >> works.
1939 F<t/op/filetest_t.t> tests if -t file test works.
1943 F<t/op/qr.t> tests C<qr>.
1947 F<t/op/utf8cache.t> tests malfunctions of the utf8 cache.
1951 F<t/re/uniprops.t> test unicodes C<\p{}> regex constructs.
1955 F<t/op/filehandle.t> tests some suitably portable filetest operators
1956 to check that they work as expected, particularly in the light of some
1957 internal changes made in how filehandles are blessed.
1961 F<t/op/time_loop.t> tests that unix times greater than C<2**63>, which
1962 can now be handed to C<gmtime> and C<localtime>, do not cause an internal
1963 overflow or an excessively long loop.
1968 =head1 New or Changed Diagnostics
1970 =head2 New Diagnostics
1976 SV allocation tracing has been added to the diagnostics enabled by C<-Dm>.
1977 The tracing can alternatively output via the C<PERL_MEM_LOG> mechanism, if
1978 that was enabled when the F<perl> binary was compiled.
1982 Smartmatch resolution tracing has been added as a new diagnostic. Use C<-DM> to
1987 A new debugging flag C<-DB> now dumps subroutine definitions, leaving
1988 C<-Dx> for its original purpose of dumping syntax trees.
1992 Perl 5.12 provides a number of new diagnostic messages to help you write
1993 better code. See L<perldiag> for details of these new messages.
1999 C<Bad plugin affecting keyword '%s'>
2003 C<gmtime(%.0f) too large>
2007 C<Lexing code attempted to stuff non-Latin-1 character into Latin-1 input>
2011 C<Lexing code internal error (%s)>
2015 C<localtime(%.0f) too large>
2019 C<Overloaded dereference did not return a reference>
2023 C<Overloaded qr did not return a REGEXP>
2027 C<Perl_pmflag() is deprecated, and will be removed from the XS API>
2031 C<lvalue attribute ignored after the subroutine has been defined>
2033 This new warning is issued when one attempts to mark a subroutine as
2034 lvalue after it has been defined.
2038 Perl now warns you if C<++> or C<--> are unable to change the value because it's
2039 beyond the limit of representation.
2041 This uses a new warnings category: "imprecision".
2045 C<lc>, C<uc>, C<lcfirst>, and C<ucfirst> warn when passed undef.
2049 C<Show constant in "Useless use of a constant in void context">
2053 C<Prototype after '%s'>
2057 C<panic: sv_chop %s>
2059 This new fatal error occurs when the C routine C<Perl_sv_chop()> was
2060 passed a position that is not within the scalar's string buffer. This
2061 could be caused by buggy XS code, and at this point recovery is not
2067 The fatal error C<Malformed UTF-8 returned by \N> is now produced if the
2068 C<charnames> handler returns malformed UTF-8.
2072 If an unresolved named character or sequence was encountered when compiling a
2073 regex pattern then the fatal error C<\N{NAME} must be resolved by the lexer>
2074 is now produced. This can happen, for example, when using a single-quotish
2075 context like C<$re = '\N{SPACE}'; /$re/;>. See L<perldiag> for more examples of
2076 how the lexer can get bypassed.
2080 C<Invalid hexadecimal number in \N{U+...}> is a new fatal error triggered when
2081 the character constant represented by C<...> is not a valid hexadecimal
2086 The new meaning of C<\N> as C<[^\n]> is not valid in a bracketed character
2087 class, just like C<.> in a character class loses its special meaning, and will
2088 cause the fatal error C<\N in a character class must be a named character: \N{...}>.
2092 The rules on what is legal for the C<...> in C<\N{...}> have been tightened
2093 up so that unless the C<...> begins with an alphabetic character and continues
2094 with a combination of alphanumerics, dashes, spaces, parentheses or colons
2095 then the warning C<Deprecated character(s) in \N{...} starting at '%s'> is
2100 The warning C<Using just the first characters returned by \N{}> will be
2101 issued if the C<charnames> handler returns a sequence of characters which
2102 exceeds the limit of the number of characters that can be used. The message
2103 will indicate which characters were used and which were discarded.
2109 =head2 Changed Diagnostics
2111 A number of existing diagnostic messages have been improved or corrected:
2117 A new warning category C<illegalproto> allows finer-grained control of
2118 warnings around function prototypes.
2124 =item C<Illegal character in prototype for %s : %s>
2126 =item C<Prototype after '%c' for %s : %s>
2130 have been moved from the C<syntax> top-level warnings category into a new
2131 first-level category, C<illegalproto>. These two warnings are currently the
2132 only ones emitted during parsing of an invalid/illegal prototype, so one
2135 no warnings 'illegalproto';
2137 to suppress only those, but not other syntax-related warnings. Warnings where
2138 prototypes are changed, ignored, or not met are still in the C<prototype>
2139 category as before. (Matt S. Trout)
2143 C<Deep recursion on subroutine "%s">
2145 It is now possible to change the depth threshold for this warning from the
2146 default of 100, by recompiling the F<perl> binary, setting the C
2147 pre-processor macro C<PERL_SUB_DEPTH_WARN> to the desired value.
2151 C<Illegal character in prototype> warning is now more precise
2152 when reporting illegal characters after _
2156 mro merging error messages are now very similar to those produced by L<Algorithm::C3>.
2160 Amelioration of the error message "Unrecognized character %s in column %d"
2162 Changes the error message to "Unrecognized character %s; marked by E<lt>--
2163 HERE after %sE<lt>-- HERE near column %d". This should make it a little
2164 simpler to spot and correct the suspicious character.
2168 Perl now explicitly points to C<$.> when it causes an uninitialized warning for
2169 ranges in scalar context.
2173 C<split> now warns when called in void context.
2177 C<printf>-style functions called with too few arguments will now issue the
2178 warning C<"Missing argument in %s"> [perl #71000]
2182 Perl now properly returns a syntax error instead of segfaulting
2183 if C<each>, C<keys>, or C<values> is used without an argument.
2187 C<tell()> now fails properly if called without an argument and when no
2188 previous file was read.
2190 C<tell()> now returns C<-1>, and sets errno to C<EBADF>, thus restoring
2191 the 5.8.x behaviour.
2195 C<overload> no longer implicitly unsets fallback on repeated 'use
2200 POSIX::strftime() can now handle Unicode characters in the format string.
2204 The C<syntax> category was removed from 5 warnings that should only be in
2209 Three fatal C<pack>/C<unpack> error messages have been normalized to
2214 C<Unicode character is illegal> has been rephrased to be more accurate
2216 It now reads C<Unicode non-character is illegal in interchange> and the
2217 perldiag documentation has been expanded a bit.
2221 Currently, all but the first of the several characters that the C<charnames>
2222 handler may return are discarded when used in a regular expression pattern
2223 bracketed character class. If this happens then the warning C<Using just the
2224 first character returned by \N{} in character class> will be issued.
2228 The warning C<Missing right brace on \N{} or unescaped left brace after \N.
2229 Assuming the latter> will be issued if Perl encounters a C<\N{> but doesn't
2230 find a matching C<}>. In this case Perl doesn't know if it was mistakenly
2231 omitted, or if "match non-newline" followed by "match a C<{>" was desired.
2232 It assumes the latter because that is actually a valid interpretation as
2233 written, unlike the other case. If you meant the former, you need to add the
2234 matching right brace. If you did mean the latter, you can silence this
2235 warning by writing instead C<\N\{>.
2239 C<gmtime> and C<localtime> called with numbers smaller than they can reliably
2240 handle will now issue the warnings C<gmtime(%.0f) too small> and
2241 C<localtime(%.0f) too small>.
2245 The following diagnostic messages have been removed:
2255 C<Can't locate package %s for the parents of %s>
2257 In general this warning it only got produced in
2258 conjunction with other warnings, and removing it allowed an ISA lookup
2259 optimisation to be added.
2263 C<v-string in use/require is non-portable>
2267 =head1 Utility Changes
2273 F<h2ph> now looks in C<include-fixed> too, which is a recent addition to gcc's
2278 F<h2xs> no longer incorrectly treats enum values like macros (Daniel Burr).
2279 It also now handles C++ style constants (C<//>) properly in enums. (A patch from
2280 Rainer Weikusat was used; Daniel Burr also proposed a similar fix).
2284 F<perl5db.pl> now supports C<LVALUE> subroutines. Additionally, the
2285 debugger now correctly handles proxy constant subroutines, and
2290 F<perlbug> now uses C<%Module::CoreList::bug_tracker> to print out
2291 upstream bug tracker URLs. If a user identifies a particular module
2292 as the topic of their bug report and we're able to divine the URL for
2293 its upstream bug tracker, perlbug now provide a message to the user
2294 explaining that the core copies the CPAN version directly, and provide
2295 the URL for reporting the bug directly to the upstream author.
2297 F<perlbug> no longer reports "Message sent" when it hasn't actually sent the message
2301 F<perlthanks> is a new utility for sending non-bug-reports to the
2302 authors and maintainers of Perl. Getting nothing but bug reports can
2303 become a bit demoralising. If Perl 5.12 works well for you, please try
2304 out F<perlthanks>. It will make the developers smile.
2308 Perl's developers have fixed bugs in F<a2p> having to do with the
2309 C<match()> operator in list context.
2313 =head1 Selected Bug Fixes
2319 U+0FFFF is now a legal character in regular expressions.
2323 pp_qr now always returns a new regexp SV. Resolves RT #69852.
2325 Instead of returning a(nother) reference to the (pre-compiled) regexp in the
2326 optree, use reg_temp_copy() to create a copy of it, and return a reference to
2327 that. This resolves issues about Regexp::DESTROY not being called in a timely
2328 fashion (the original bug tracked by RT #69852), as well as bugs related to
2329 blessing regexps, and of assigning to regexps, as described in correspondence
2330 added to the ticket.
2332 It transpires that we also need to undo the SvPVX() sharing when ithreads
2333 cloning a Regexp SV, because mother_re is set to NULL, instead of a cloned
2334 copy of the mother_re. This change might fix bugs with regexps and threads in
2335 certain other situations, but as yet neither tests nor bug reports have
2336 indicated any problems, so it might not actually be an edge case that it's
2341 Several compilation errors and segfaults when perl was built with C<-Dmad> were fixed.
2345 Fixes for lexer API changes in 5.11.2 which broke NYTProf's savesrc option.
2349 C<-t> should only return TRUE for file handles connected to a TTY
2351 The Microsoft C version of C<isatty()> returns TRUE for all
2352 character mode devices, including the F</dev/null>-style "nul"
2353 device and printers like "lpt1".
2357 Fixed a regression caused by commit fafafbaf which caused a panic during
2358 parameter passing [perl #70171]
2362 On systems which in-place edits without backup files, -i'*' now works as
2363 the documentation says it does [perl #70802]
2367 Saving and restoring magic flags no longer loses readonly flag.
2371 The malformed syntax C<grep EXPR LIST> (note the missing comma) no longer
2372 causes abrupt and total failure.
2376 Regular expressions compiled with C<qr{}> literals properly set C<$'> when
2381 Using named subroutines with C<sort> should no longer lead to bus errors [perl
2386 Numerous bugfixes catch small issues caused by the recently-added Lexer API.
2390 Smart match against C<@_> sometimes gave false negatives. [perl #71078]
2394 C<$@> may now be assigned a read-only value (without error or busting
2399 C<sort> called recursively from within an active comparison subroutine no
2400 longer causes a bus error if run multiple times. [perl #71076]
2404 Tie::Hash::NamedCapture::* will not abort if passed bad input (RT #71828)
2408 @_ and $_ no longer leak under threads (RT #34342 and #41138, also
2413 C<-I> on shebang line now adds directories in front of @INC
2414 as documented, and as does C<-I> when specified on the command-line.
2418 C<kill> is now fatal when called on non-numeric process identifiers.
2419 Previously, an C<undef> process identifier would be interpreted as a
2420 request to kill process 0, which would terminate the current process
2421 group on POSIX systems. Since process identifiers are always integers,
2422 killing a non-numeric process is now fatal.
2426 5.10.0 inadvertently disabled an optimisation, which caused a measurable
2427 performance drop in list assignment, such as is often used to assign
2428 function parameters from C<@_>. The optimisation has been re-instated, and
2429 the performance regression fixed. (This fix is also present in 5.10.1)
2433 Fixed memory leak on C<while (1) { map 1, 1 }> [RT #53038].
2437 Some potential coredumps in PerlIO fixed [RT #57322,54828].
2441 The debugger now works with lvalue subroutines.
2445 The debugger's C<m> command was broken on modules that defined constants
2450 C<crypt> and string complement could return tainted values for untainted
2451 arguments [RT #59998].
2455 The C<-i>I<.suffix> command-line switch now recreates the file using
2456 restricted permissions, before changing its mode to match the original
2457 file. This eliminates a potential race condition [RT #60904].
2461 On some Unix systems, the value in C<$?> would not have the top bit set
2462 (C<$? & 128>) even if the child core dumped.
2466 Under some circumstances, C<$^R> could incorrectly become undefined
2471 In the XS API, various hash functions, when passed a pre-computed hash where
2472 the key is UTF-8, might result in an incorrect lookup.
2476 XS code including F<XSUB.h> before F<perl.h> gave a compile-time error
2481 C<< $object-E<gt>isa('Foo') >> would report false if the package C<Foo> didn't
2482 exist, even if the object's C<@ISA> contained C<Foo>.
2486 Various bugs in the new-to 5.10.0 mro code, triggered by manipulating
2487 C<@ISA>, have been found and fixed.
2491 Bitwise operations on references could crash the interpreter, e.g.
2492 C<$x=\$y; $x |= "foo"> [RT #54956].
2496 Patterns including alternation might be sensitive to the internal UTF-8
2497 representation, e.g.
2499 my $byte = chr(192);
2500 my $utf8 = chr(192); utf8::upgrade($utf8);
2501 $utf8 =~ /$byte|X}/i; # failed in 5.10.0
2505 Within UTF8-encoded Perl source files (i.e. where C<use utf8> is in
2506 effect), double-quoted literal strings could be corrupted where a C<\xNN>,
2507 C<\0NNN> or C<\N{}> is followed by a literal character with ordinal value
2508 greater than 255 [RT #59908].
2512 C<B::Deparse> failed to correctly deparse various constructs:
2513 C<readpipe STRING> [RT #62428], C<CORE::require(STRING)> [RT #62488],
2514 C<sub foo(_)> [RT #62484].
2518 Using C<setpgrp> with no arguments could corrupt the perl stack.
2522 The block form of C<eval> is now specifically trappable by C<Safe> and
2523 C<ops>. Previously it was erroneously treated like string C<eval>.
2527 In 5.10.0, the two characters C<[~> were sometimes parsed as the smart
2528 match operator (C<~~>) [RT #63854].
2532 In 5.10.0, the C<*> quantifier in patterns was sometimes treated as
2533 C<{0,32767}> [RT #60034, #60464]. For example, this match would fail:
2535 ("ab" x 32768) =~ /^(ab)*$/
2539 C<shmget> was limited to a 32 bit segment size on a 64 bit OS [RT #63924].
2543 Using C<next> or C<last> to exit a C<given> block no longer produces a
2544 spurious warning like the following:
2546 Exiting given via last at foo.pl line 123
2550 Assigning a format to a glob could corrupt the format; e.g.:
2552 *bar=*foo{FORMAT}; # foo format now bad
2556 Attempting to coerce a typeglob to a string or number could cause an
2557 assertion failure. The correct error message is now generated,
2558 C<Can't coerce GLOB to I<$type>>.
2562 Under C<use filetest 'access'>, C<-x> was using the wrong access mode. This
2563 has been fixed [RT #49003].
2567 C<length> on a tied scalar that returned a Unicode value would not be
2568 correct the first time. This has been fixed.
2572 Using an array C<tie> inside in array C<tie> could SEGV. This has been
2577 A race condition inside C<PerlIOStdio_close()> has been identified and
2578 fixed. This used to cause various threading issues, including SEGVs.
2582 In C<unpack>, the use of C<()> groups in scalar context was internally
2583 placing a list on the interpreter's stack, which manifested in various
2584 ways, including SEGVs. This is now fixed [RT #50256].
2588 Magic was called twice in C<substr>, C<\&$x>, C<tie $x, $m> and C<chop>.
2589 These have all been fixed.
2593 A 5.10.0 optimisation to clear the temporary stack within the implicit
2594 loop of C<s///ge> has been reverted, as it turned out to be the cause of
2595 obscure bugs in seemingly unrelated parts of the interpreter [commit
2600 The line numbers for warnings inside C<elsif> are now correct.
2604 The C<..> operator now works correctly with ranges whose ends are at or
2605 close to the values of the smallest and largest integers.
2609 C<binmode STDIN, ':raw'> could lead to segmentation faults on some platforms.
2610 This has been fixed [RT #54828].
2614 An off-by-one error meant that C<index $str, ...> was effectively being
2615 executed as C<index "$str\0", ...>. This has been fixed [RT #53746].
2619 Various leaks associated with named captures in regexes have been fixed
2624 A weak reference to a hash would leak. This was affecting C<DBI>
2629 Using (?|) in a regex could cause a segfault [RT #59734].
2633 Use of a UTF-8 C<tr//> within a closure could cause a segfault [RT #61520].
2637 Calling C<Perl_sv_chop()> or otherwise upgrading an SV could result in an
2638 unaligned 64-bit access on the SPARC architecture [RT #60574].
2642 In the 5.10.0 release, C<inc_version_list> would incorrectly list
2643 C<5.10.*> after C<5.8.*>; this affected the C<@INC> search order
2648 In 5.10.0, C<pack "a*", $tainted_value> returned a non-tainted value
2653 In 5.10.0, C<printf> and C<sprintf> could produce the fatal error
2654 C<panic: utf8_mg_pos_cache_update> when printing UTF-8 strings
2659 In the 5.10.0 release, a dynamically created C<AUTOLOAD> method might be
2660 missed (method cache issue) [RT #60220,60232].
2664 In the 5.10.0 release, a combination of C<use feature> and C<//ee> could
2665 cause a memory leak [RT #63110].
2669 C<-C> on the shebang (C<#!>) line is once more permitted if it is also
2670 specified on the command line. C<-C> on the shebang line used to be a
2671 silent no-op I<if> it was not also on the command line, so perl 5.10.0
2672 disallowed it, which broke some scripts. Now perl checks whether it is
2673 also on the command line and only dies if it is not [RT #67880].
2677 In 5.10.0, certain types of re-entrant regular expression could crash,
2678 or cause the following assertion failure [RT #60508]:
2680 Assertion rx->sublen >= (s - rx->subbeg) + i failed
2684 Perl now includes previously missing files from the Unicode Character Database.
2688 Perl now honors C<TMPDIR> when opening an anonymous temporary file.
2693 =head1 Platform Specific Changes
2695 Perl is incredibly portable. In general, if a platform has a C compiler,
2696 someone has ported Perl to it (or will soon). We're happy to announce
2697 that Perl 5.12 includes support for several new platforms. At the same
2698 time, it's time to bid farewell to some (very) old friends.
2700 =head2 New Platforms
2706 Perl's developers have merged patches from Haiku's maintainers. Perl should now
2711 Perl should now build on MirOS BSD.
2715 =head2 Discontinued Platforms
2727 =head2 Updated Platforms
2737 Removed F<libbsd> for AIX 5L and 6.1. Only C<flock()> was used from F<libbsd>.
2741 Removed F<libgdbm> for AIX 5L and 6.1 if F<libgdbm> < 1.8.3-5 is installed.
2742 The F<libgdbm> is delivered as an optional package with the AIX Toolbox.
2743 Unfortunately the versions below 1.8.3-5 are broken.
2747 Hints changes mean that AIX 4.2 should work again.
2757 Perl now supports IPv6 on Cygwin 1.7 and newer.
2761 On Cygwin we now strip the last number from the DLL. This has been the
2762 behaviour in the cygwin.com build for years. The hints files have been
2767 =item Darwin (Mac OS X)
2773 Skip testing the be_BY.CP1131 locale on Darwin 10 (Mac OS X 10.6),
2774 as it's still buggy.
2778 Correct infelicities in the regexp used to identify buggy locales
2779 on Darwin 8 and 9 (Mac OS X 10.4 and 10.5, respectively).
2789 Fix thread library selection [perl #69686]
2799 The hints files now identify the correct threading libraries on FreeBSD 7
2810 We now work around a bizarre preprocessor bug in the Irix 6.5 compiler:
2811 C<cc -E -> unfortunately goes into K&R mode, but C<cc -E file.c> doesn't.
2821 Hints now supports versions 5.*.
2831 C<-UDEBUGGING> is now the default on VMS.
2833 Like it has been everywhere else for ages and ages. Also make
2834 command-line selection of -UDEBUGGING and -DDEBUGGING work in
2835 configure.com; before the only way to turn it off was by saying
2836 no in answer to the interactive question.
2840 The default pipe buffer size on VMS has been updated to 8192 on 64-bit
2845 Reads from the in-memory temporary files of C<PerlIO::scalar> used to fail
2846 if C<$/> was set to a numeric reference (to indicate record-style reads).
2851 VMS now supports C<getgrgid>.
2855 Many improvements and cleanups have been made to the VMS file name handling
2856 and conversion code.
2860 Enabling the C<PERL_VMS_POSIX_EXIT> logical name now encodes a POSIX exit
2861 status in a VMS condition value for better interaction with GNV's bash
2862 shell and other utilities that depend on POSIX exit values. See
2863 L<perlvms/"$?"> for details.
2867 C<File::Copy> now detects Unix compatibility mode on VMS.
2877 Various changes from Stratus have been merged in.
2887 There is now support for Symbian S60 3.2 SDK and S60 5.0 SDK.
2897 Perl 5.12 supports Windows 2000 and later. The supporting code for
2898 legacy versions of Windows is still included, but will be removed
2899 during the next development cycle.
2903 Initial support for building Perl with MinGW-w64 is now available.
2907 F<perl.exe> now includes a manifest resource to specify the C<trustInfo>
2908 settings for Windows Vista and later. Without this setting Windows
2909 would treat F<perl.exe> as a legacy application and apply various
2910 heuristics like redirecting access to protected file system areas
2911 (like the "Program Files" folder) to the users "VirtualStore"
2912 instead of generating a proper "permission denied" error.
2914 The manifest resource also requests the Microsoft Common-Controls
2915 version 6.0 (themed controls introduced in Windows XP). Check out the
2916 Win32::VisualStyles module on CPAN to switch back to old style
2917 unthemed controls for legacy applications.
2921 The C<-t> filetest operator now only returns true if the filehandle
2922 is connected to a console window. In previous versions of Perl it
2923 would return true for all character mode devices, including F<NUL>
2928 The C<-p> filetest operator now works correctly, and the
2929 Fcntl::S_IFIFO constant is defined when Perl is compiled with
2930 Microsoft Visual C. In previous Perl versions C<-p> always
2931 returned a false value, and the Fcntl::S_IFIFO constant
2934 This bug is specific to Microsoft Visual C and never affected
2935 Perl binaries built with MinGW.
2939 The socket error codes are now more widely supported: The POSIX
2940 module will define the symbolic names, like POSIX::EWOULDBLOCK,
2941 and stringification of socket error codes in $! works as well
2944 C:\>perl -MPOSIX -E "$!=POSIX::EWOULDBLOCK; say $!"
2945 A non-blocking socket operation could not be completed immediately.
2949 flock() will now set sensible error codes in $!. Previous Perl versions
2950 copied the value of $^E into $!, which caused much confusion.
2954 select() now supports all empty C<fd_set>s more correctly.
2958 C<'.\foo'> and C<'..\foo'> were treated differently than
2959 C<'./foo'> and C<'../foo'> by C<do> and C<require> [RT #63492].
2963 Improved message window handling means that C<alarm> and C<kill> messages
2964 will no longer be dropped under race conditions.
2968 Various bits of Perl's build infrastructure are no longer converted to
2969 win32 line endings at release time. If this hurts you, please report the
2970 problem with the L<perlbug> program included with perl.
2977 =head1 Known Problems
2979 This is a list of some significant unfixed bugs, which are regressions
2980 from either 5.10.x or 5.8.x.
2986 C<List::Util::first> misbehaves in the presence of a lexical C<$_>
2987 (typically introduced by C<my $_> or implicitly by C<given>). The variable
2988 which gets set for each iteration is the package variable C<$_>, not the
2989 lexical C<$_> [RT #67694].
2991 A similar issue may occur in other modules that provide functions which
2992 take a block as their first argument, like
2994 foo { ... $_ ...} list
2998 Some regexes may run much more slowly when run in a child thread compared
2999 with the thread the pattern was compiled into [RT #55600].
3003 Things like C<"\N{LATIN SMALL LIGATURE FF}" =~ /\N{LATIN SMALL LETTER F}+/>
3004 will appear to hang as they get into a very long running loop [RT #72998].
3008 Several porters have reported mysterious crashes when Perl's entire
3009 test suite is run after a build on certain Windows 2000 systems. When
3010 run by hand, the individual tests reportedly work fine.
3020 This one is actually a change introduced in 5.10.0, but it was missed
3021 from that release's perldelta, so it is mentioned here instead.
3023 A bugfix related to the handling of the C</m> modifier and C<qr> resulted
3024 in a change of behaviour between 5.8.x and 5.10.0:
3026 # matches in 5.8.x, doesn't match in 5.10.0
3027 $re = qr/^bar/; "foo\nbar" =~ /$re/m;
3031 =head1 Acknowledgements
3033 Perl 5.12.0 represents approximately two years of development since
3034 Perl 5.10.0 and contains over 750,000 lines of changes across over
3035 3,000 files from over 200 authors and committers.
3037 Perl continues to flourish into its third decade thanks to a vibrant
3038 community of users and developers. The following people are known to
3039 have contributed the improvements that became Perl 5.12.0:
3041 Aaron Crane, Abe Timmerman, Abhijit Menon-Sen, Abigail, Adam Russell,
3042 Adriano Ferreira, Ævar Arnfjörð Bjarmason, Alan Grover, Alexandr
3043 Ciornii, Alex Davies, Alex Vandiver, Andreas Koenig, Andrew Rodland,
3044 andrew@sundale.net, Andy Armstrong, Andy Dougherty, Jose AUGUSTE-ETIENNE,
3045 Benjamin Smith, Ben Morrow, bharanee rathna, Bo Borgerson, Bo Lindbergh,
3046 Brad Gilbert, Bram, Brendan O'Dea, brian d foy, Charles Bailey,
3047 Chip Salzenberg, Chris 'BinGOs' Williams, Christoph Lamprecht, Chris
3048 Williams, chromatic, Claes Jakobsson, Craig A. Berry, Dan Dascalescu,
3049 Daniel Frederick Crisman, Daniel M. Quinlan, Dan Jacobson, Dan Kogai,
3050 Dave Mitchell, Dave Rolsky, David Cantrell, David Dick, David Golden,
3051 David Mitchell, David M. Syzdek, David Nicol, David Wheeler, Dennis
3052 Kaarsemaker, Dintelmann, Peter, Dominic Dunlop, Dr.Ruud, Duke Leto,
3053 Enrico Sorcinelli, Eric Brine, Father Chrysostomos, Florian Ragwitz,
3054 Frank Wiegand, Gabor Szabo, Gene Sullivan, Geoffrey T. Dairiki, George
3055 Greer, Gerard Goossen, Gisle Aas, Goro Fuji, Graham Barr, Green, Paul,
3056 Hans Dieter Pearcey, Harmen, H. Merijn Brand, Hugo van der Sanden,
3057 Ian Goodacre, Igor Sutton, Ingo Weinhold, James Bence, James Mastros,
3058 Jan Dubois, Jari Aalto, Jarkko Hietaniemi, Jay Hannah, Jerry Hedden,
3059 Jesse Vincent, Jim Cromie, Jody Belka, John E. Malmberg, John Malmberg,
3060 John Peacock, John Peacock via RT, John P. Linderman, John Wright,
3061 Josh ben Jore, Jos I. Boumans, Karl Williamson, Kenichi Ishigaki, Ken
3062 Williams, Kevin Brintnall, Kevin Ryde, Kurt Starsinic, Leon Brocard,
3063 Lubomir Rintel, Luke Ross, Marcel Grünauer, Marcus Holland-Moritz, Mark
3064 Jason Dominus, Marko Asplund, Martin Hasch, Mashrab Kuvatov, Matt Kraai,
3065 Matt S Trout, Max Maischein, Michael Breen, Michael Cartmell, Michael
3066 G Schwern, Michael Witten, Mike Giroux, Milosz Tanski, Moritz Lenz,
3067 Nicholas Clark, Nick Cleaton, Niko Tyni, Offer Kaye, Osvaldo Villalon,
3068 Paul Fenwick, Paul Gaborit, Paul Green, Paul Johnson, Paul Marquess,
3069 Philip Hazel, Philippe Bruhat, Rafael Garcia-Suarez, Rainer Tammer,
3070 Rajesh Mandalemula, Reini Urban, Renée Bäcker, Ricardo Signes,
3071 Ricardo SIGNES, Richard Foley, Rich Rauenzahn, Rick Delaney, Risto
3072 Kankkunen, Robert May, Roberto C. Sanchez, Robin Barker, SADAHIRO
3073 Tomoyuki, Salvador Ortiz Garcia, Sam Vilain, Scott Lanning, Sébastien
3074 Aperghis-Tramoni, Sérgio Durigan Júnior, Shlomi Fish, Simon 'corecode'
3075 Schubert, Sisyphus, Slaven Rezic, Smylers, Steffen Müller, Steffen
3076 Ullrich, Stepan Kasal, Steve Hay, Steven Schubiger, Steve Peters, Tels,
3077 The Doctor, Tim Bunce, Tim Jenness, Todd Rinaldo, Tom Christiansen,
3078 Tom Hukins, Tom Wyant, Tony Cook, Torsten Schoenfeld, Tye McQueen,
3079 Vadim Konovalov, Vincent Pit, Hio YAMASHINA, Yasuhiro Matsumoto,
3080 Yitzchak Scott-Thoennes, Yuval Kogman, Yves Orton, Zefram, Zsban Ambrus
3082 This is woefully incomplete as it's automatically generated from version
3083 control history. In particular, it doesn't include the names of the
3084 (very much appreciated) contributors who reported issues in previous
3085 versions of Perl that helped make Perl 5.12.0 better. For a more complete
3086 list of all of Perl's historical contributors, please see the C<AUTHORS>
3087 file in the Perl 5.12.0 distribution.
3089 Many of the changes included in this version originated in the CPAN
3090 modules included in Perl's core. We're grateful to the entire CPAN
3091 community for helping Perl to flourish.
3093 =head1 Reporting Bugs
3095 If you find what you think is a bug, you might check the articles
3096 recently posted to the comp.lang.perl.misc newsgroup and the perl
3097 bug database at L<http://rt.perl.org/perlbug/>. There may also be
3098 information at L<http://www.perl.org/>, the Perl Home Page.
3100 If you believe you have an unreported bug, please run the B<perlbug>
3101 program included with your release. Be sure to trim your bug down
3102 to a tiny but sufficient test case. Your bug report, along with the
3103 output of C<perl -V>, will be sent off to perlbug@perl.org to be
3104 analyzed by the Perl porting team.
3106 If the bug you are reporting has security implications, which make it
3107 inappropriate to send to a publicly archived mailing list, then please send
3108 it to perl5-security-report@perl.org. This points to a closed subscription
3109 unarchived mailing list, which includes all the core committers, who be able
3110 to help assess the impact of issues, figure out a resolution, and help
3111 co-ordinate the release of patches to mitigate or fix the problem across all
3112 platforms on which Perl is supported. Please only use this address for
3113 security issues in the Perl core, not for modules independently
3114 distributed on CPAN.
3118 The F<Changes> file for an explanation of how to view exhaustive details
3121 The F<INSTALL> file for how to build Perl.
3123 The F<README> file for general stuff.
3125 The F<Artistic> and F<Copying> files for copyright information.