5 perl5120delta - what is new for perl v5.12.0
9 This document describes differences between the 5.10.0 release and the
12 Many of the bug fixes in 5.12.0 are already included in the 5.10.1
15 You can see the list of those changes in the 5.10.1 release notes
19 =head1 Core Enhancements
21 =head2 New C<package NAME VERSION> syntax
23 This new syntax allows a module author to set the $VERSION of a namespace
24 when the namespace is declared with 'package'. It eliminates the need
25 for C<our $VERSION = ...> and similar constructs. E.g.
27 package Foo::Bar 1.23;
28 # $Foo::Bar::VERSION == 1.23
30 There are several advantages to this:
36 C<$VERSION> is parsed in exactly the same way as C<use NAME VERSION>
40 C<$VERSION> is set at compile time
44 C<$VERSION> is a version object that provides proper overloading of
45 comparison operators so comparing C<$VERSION> to decimal (1.23) or
46 dotted-decimal (v1.2.3) version numbers works correctly.
50 Eliminates C<$VERSION = ...> and C<eval $VERSION> clutter
54 As it requires VERSION to be a numeric literal or v-string
55 literal, it can be statically parsed by toolchain modules
56 without C<eval> the way MM-E<gt>parse_version does for C<$VERSION = ...>
60 It does not break old code with only C<package NAME>, but code that uses
61 C<package NAME VERSION> will need to be restricted to perl 5.12.0 or newer
62 This is analogous to the change to C<open> from two-args to three-args.
63 Users requiring the latest Perl will benefit, and perhaps after several
64 years, it will become a standard practice.
67 However, C<package NAME VERSION> requires a new, 'strict' version
68 number format. See L<"Version number formats"> for details.
71 =head2 The C<...> operator
73 A new operator, C<...>, nicknamed the Yada Yada operator, has been added.
74 It is intended to mark placeholder code that is not yet implemented.
75 See L<perlop/"Yada Yada Operator">.
77 =head2 Implicit strictures
79 Using the C<use VERSION> syntax with a version number greater or equal
80 to 5.11.0 will lexically enable strictures just like C<use strict>
81 would do (in addition to enabling features.) The following:
90 =head2 Unicode improvements
92 Perl 5.12 comes with Unicode 5.2, the latest version available to
93 us at the time of release. This version of Unicode was released in
94 October 2009. See L<http://www.unicode.org/versions/Unicode5.2.0> for
95 further details about what's changed in this version of the standard.
96 See L<perlunicode> for instructions on installing and using other versions
99 Additionally, Perl's developers have significantly improved Perl's Unicode
100 implementation. For full details, see L</Unicode overhaul> below.
102 =head2 Y2038 compliance
104 Perl's core time-related functions are now Y2038 compliant. (It may not mean much to you, but your kids will love it!)
106 =head2 qr overloading
108 It is now possible to overload the C<qr//> operator, that is,
109 conversion to regexp, like it was already possible to overload
110 conversion to boolean, string or number of objects. It is invoked when
111 an object appears on the right hand side of the C<=~> operator or when
112 it is interpolated into a regexp. See L<overload>.
114 =head2 Pluggable keywords
116 Extension modules can now cleanly hook into the Perl parser to define
117 new kinds of keyword-headed expression and compound statement. The
118 syntax following the keyword is defined entirely by the extension. This
119 allow a completely non-Perl sublanguage to be parsed inline, with the
120 correct ops cleanly generated.
122 See L<perlapi/PL_keyword_plugin> for the mechanism. The Perl core
123 source distribution also includes a new module
124 L<XS::APItest::KeywordRPN>, which implements reverse Polish notation
125 arithmetic via pluggable keywords. This module is mainly used for test
126 purposes, and is not normally installed, but also serves as an example
127 of how to use the new mechanism.
129 Perl's developers consider this feature to be experimental. We may remove
130 it or change it in a backwards-incompatible way in Perl 5.14.
132 =head2 APIs for more internals
134 The lowest layers of the lexer and parts of the pad system now have C
135 APIs available to XS extensions. These are necessary to support proper
136 use of pluggable keywords, but have other uses too. The new APIs are
137 experimental, and only cover a small proportion of what would be
138 necessary to take full advantage of the core's facilities in these
139 areas. It is intended that the Perl 5.13 development cycle will see the
140 addition of a full range of clean, supported interfaces.
142 Perl's developers consider this feature to be experimental. We may remove
143 it or change it in a backwards-incompatible way in Perl 5.14.
145 =head2 Overridable function lookup
147 Where an extension module hooks the creation of rv2cv ops to modify the
148 subroutine lookup process, this now works correctly for bareword
149 subroutine calls. This means that prototypes on subroutines referenced
150 this way will be processed correctly. (Previously bareword subroutine
151 names were initially looked up, for parsing purposes, by an unhookable
152 mechanism, so extensions could only properly influence subroutine names
153 that appeared with an C<&> sigil.)
155 =head2 A proper interface for pluggable Method Resolution Orders
157 As of Perl 5.12.0 there is a new interface for plugging and using method
158 resolution orders other than the default linear depth first search.
159 The C3 method resolution order added in 5.10.0 has been re-implemented as
160 a plugin, without changing its Perl-space interface. See L<perlmroapi> for
165 =head2 C<\N> experimental regex escape
167 Perl now supports C<\N>, a new regex escape which you can think of as
168 the inverse of C<\n>. It will match any character that is not a newline,
169 independently from the presence or absence of the single line match
170 modifier C</s>. It is not usable within a character class. C<\N{3}>
171 means to match 3 non-newlines; C<\N{5,}> means to match at least 5.
172 C<\N{NAME}> still means the character or sequence named C<NAME>, but
173 C<NAME> no longer can be things like C<3>, or C<5,>.
175 This will break a L<custom charnames translator|charnames/CUSTOM
176 TRANSLATORS> which allows numbers for character names, as C<\N{3}> will
177 now mean to match 3 non-newline characters, and not the character whose
178 name is C<3>. (No name defined by the Unicode standard is a number,
179 so only custom translators might be affected.)
181 Perl's developers are somewhat concerned about possible user confusion
182 with the existing C<\N{...}> construct which matches characters by their
183 Unicode name. Consequently, this feature is experimental. We may remove
184 it or change it in a backwards-incompatible way in Perl 5.14.
186 =head2 DTrace support
188 Perl now has some support for DTrace. See "DTrace support" in F<INSTALL>.
190 =head2 Support for C<configure_requires> in CPAN module metadata
192 Both C<CPAN> and C<CPANPLUS> now support the C<configure_requires>
193 keyword in the F<META.yml> metadata file included in most recent CPAN
194 distributions. This allows distribution authors to specify configuration
195 prerequisites that must be installed before running F<Makefile.PL>
198 See the documentation for C<ExtUtils::MakeMaker> or C<Module::Build> for
199 more on how to specify C<configure_requires> when creating a distribution
202 =head2 C<each> is now more flexible
204 The C<each> function can now operate on arrays.
206 =head2 C<when> as a statement modifier
208 C<when> is now allowed to be used as a statement modifier.
210 =head2 C<$,> flexibility
212 The variable C<$,> may now be tied.
214 =head2 // in when clauses
216 // now behaves like || in when clauses
218 =head2 Enabling warnings from your shell environment
220 You can now set C<-W> from the C<PERL5OPT> environment variable
222 =head2 C<delete local>
224 C<delete local> now allows you to locally delete a hash entry.
226 =head2 New support for Abstract namespace sockets
228 Abstract namespace sockets are Linux-specific socket type that live in
229 AF_UNIX family, slightly abusing it to be able to use arbitrary
230 character arrays as addresses: They start with nul byte and are not
231 terminated by nul byte, but with the length passed to the socket()
234 =head2 32-bit limit on substr arguments removed
236 The 32-bit limit on C<substr> arguments has now been removed. The full
237 range of the system's signed and unsigned integers is now available for
238 the C<pos> and C<len> arguments.
240 =head1 Potentially Incompatible Changes
242 =head2 Deprecations warn by default
244 Over the years, Perl's developers have deprecated a number of language
245 features for a variety of reasons. Perl now defaults to issuing a
246 warning if a deprecated language feature is used. Many of the deprecations
247 Perl now warns you about have been deprecated for many years. You can
248 find a list of what was deprecated in a given release of Perl in the
249 C<perl5xxdelta.pod> file for that release.
251 To disable this feature in a given lexical scope, you should use C<no
252 warnings 'deprecated';> For information about which language features
253 are deprecated and explanations of various deprecation warnings, please
254 see L<perldiag.pod>. See L</Deprecations> below for the list of features
255 and modules Perl's developers have deprecated as part of this release.
257 =head2 Version number formats
259 Acceptable version number formats have been formalized into "strict" and
260 "lax" rules. C<package NAME VERSION> takes a strict version number.
261 C<UNIVERSAL::VERSION> and the L<version> object constructors take lax
262 version numbers. Providing an invalid version will result in a fatal
263 error. The version argument in C<use NAME VERSION> is first parsed as a
264 numeric literal or v-string and then passed to C<UNIVERSAL::VERSION>
265 (and must then pass the "lax" format test).
267 These formats are documented fully in the L<version> module. To a first
268 approximation, a "strict" version number is a positive decimal number
269 (integer or decimal-fraction) without exponentiation or else a
270 dotted-decimal v-string with a leading 'v' character and at least three
271 components. A "lax" version number allows v-strings with fewer than
272 three components or without a leading 'v'. Under "lax" rules, both
273 decimal and dotted-decimal versions may have a trailing "alpha"
274 component separated by an underscore character after a fractional or
275 dotted-decimal component.
277 The L<version> module adds C<version::is_strict> and C<version::is_lax>
278 functions to check a scalar against these rules.
280 =head2 @INC reorganization
282 In C<@INC>, C<ARCHLIB> and C<PRIVLIB> now occur after after the current
283 version's C<site_perl> and C<vendor_perl>. Modules installed into
284 C<site_perl> and C<vendor_perl> will now be loaded in preference to
285 those installed in C<ARCHLIB> and C<PRIVLIB>.
288 =head2 REGEXPs are now first class
290 Internally, Perl now treates compiled regular expressions (such as
291 those created with C<qr//>) as first class entities. Perl modules which
292 serialize, deserialize or otherwise have deep interaction with Perl's
293 internal data structures need to be updated for this change. Affected
294 modules include L<FreezeThaw>,L<Data::Dump::Streamer> and L<Regexp::Copy>.
297 =head2 Switch statement changes
299 The C<given>/C<when> switch statement handles complex statements better
300 than Perl 5.10.0 did (These enhancements are also available in
301 5.10.1 and subsequent 5.10 releases.) There are two new cases where
302 C<when> now interprets its argument as a boolean, instead of an
303 expression to be used in a smart match:
307 =item flip-flop operators
309 The C<..> and C<...> flip-flop operators are now evaluated in boolean
310 context, following their usual semantics; see L<perlop/"Range Operators">.
312 Note that, as in perl 5.10.0, C<when (1..10)> will not work to test
313 whether a given value is an integer between 1 and 10; you should use
314 C<when ([1..10])> instead (note the array reference).
316 However, contrary to 5.10.0, evaluating the flip-flop operators in
317 boolean context ensures it can now be useful in a C<when()>, notably
318 for implementing bistable conditions, like in:
320 when (/^=begin/ .. /^=end/) {
324 =item defined-or operator
326 A compound expression involving the defined-or operator, as in
327 C<when (expr1 // expr2)>, will be treated as boolean if the first
328 expression is boolean. (This just extends the existing rule that applies
329 to the regular or operator, as in C<when (expr1 || expr2)>.)
333 =head2 Smart match changes
335 Since Perl 5.10.0, Perl's developers have made a number of changes to
336 the smart match operator. These, of course, also alter the behaviour
337 of the switch statements where smart matching is implicitly used.
338 These changes were also made for the 5.10.1 release, and will remain in
339 subsequent 5.10 releases.
341 =head3 Changes to type-based dispatch
343 The smart match operator C<~~> is no longer commutative. The behaviour of
344 a smart match now depends primarily on the type of its right hand
345 argument. Moreover, its semantics have been adjusted for greater
346 consistency or usefulness in several cases. While the general backwards
347 compatibility is maintained, several changes must be noted:
353 Code references with an empty prototype are no longer treated specially.
354 They are passed an argument like the other code references (even if they
355 choose to ignore it).
359 C<%hash ~~ sub {}> and C<@array ~~ sub {}> now test that the subroutine
360 returns a true value for each key of the hash (or element of the
361 array), instead of passing the whole hash or array as a reference to
366 Due to the commutativity breakage, code references are no longer
367 treated specially when appearing on the left of the C<~~> operator,
368 but like any vulgar scalar.
372 C<undef ~~ %hash> is always false (since C<undef> can't be a key in a
373 hash). No implicit conversion to C<""> is done (as was the case in perl
378 C<$scalar ~~ @array> now always distributes the smart match across the
379 elements of the array. It's true if one element in @array verifies
380 C<$scalar ~~ $element>. This is a generalization of the old behaviour
381 that tested whether the array contained the scalar.
385 The full dispatch table for the smart match operator is given in
386 L<perlsyn/"Smart matching in detail">.
388 =head3 Smart match and overloading
390 According to the rule of dispatch based on the rightmost argument type,
391 when an object overloading C<~~> appears on the right side of the
392 operator, the overload routine will always be called (with a 3rd argument
393 set to a true value, see L<overload>.) However, when the object will
394 appear on the left, the overload routine will be called only when the
395 rightmost argument is a simple scalar. This way, distributivity of smart
396 match across arrays is not broken, as well as the other behaviours with
397 complex types (coderefs, hashes, regexes). Thus, writers of overloading
398 routines for smart match mostly need to worry only with comparing
399 against a scalar, and possibly with stringification overloading; the
400 other common cases will be automatically handled consistently.
402 C<~~> will now refuse to work on objects that do not overload it (in order
403 to avoid relying on the object's underlying structure). (However, if the
404 object overloads the stringification or the numification operators, and
405 if overload fallback is active, it will be used instead, as usual.)
407 =head2 Other potentially incompatible changes
413 The definitions of a number of Unicode properties have changed to match
414 those of the current Unicode standard. These are listed above under
415 L</Unicode overhaul>. This change may break code that expects the old
420 The boolkeys op has moved to the group of hash ops. This breaks binary
425 Filehandles are now always blessed into C<IO::File>.
427 The previous behaviour was to bless Filehandles into L<FileHandle>
428 (an empty proxy class) if it was loaded into memory and otherwise
429 to bless them into C<IO::Handle>.
433 The semantics of C<use feature :5.10*> have changed slightly.
434 See L<"Modules and Pragmata"> for more information.
438 Perl's developers now use git, rather than Perforce. This should be
439 a purely internal change only relevant to people actively working on
440 the core. However, you may see minor difference in perl as a consequence
441 of the change. For example in some of details of the output of C<perl
442 -V>. See L<perlrepository> for more information.
446 As part of the C<Test::Harness> 2.x to 3.x upgrade, the experimental
447 C<Test::Harness::Straps> module has been removed.
448 See L</"Modules and Pragmata"> for more details.
452 As part of the C<ExtUtils::MakeMaker> upgrade, the
453 C<ExtUtils::MakeMaker::bytes> and C<ExtUtils::MakeMaker::vmsish> modules
454 have been removed from this distribution.
458 C<Module::CoreList> no longer contains the C<%:patchlevel> hash.
463 C<length undef> now returns undef.
467 Unsupported private C API functions are now declared "static" to prevent
468 leakage to Perl's public API.
472 To support the bootstrapping process, F<miniperl> no longer builds with
473 UTF-8 support in the regexp engine.
475 This allows a build to complete with PERL_UNICODE set and a UTF-8 locale.
476 Without this there's a bootstrapping problem, as miniperl can't load
477 the UTF-8 components of the regexp engine, because they're not yet built.
481 F<miniperl>'s @INC is now restricted to just C<-I...>, the split of
482 C<$ENV{PERL5LIB}>, and "C<.>"
486 A space or a newline is now required after a C<"#line XXX"> directive.
490 Tied filehandles now have an additional method EOF which provides the
495 To better match all other flow control statements, C<foreach> may no
496 longer be used as an attribute.
503 From time to time, Perl's developers find it necessary to deprecate
504 features or modules we've previously shipped as part of the core
505 distribution. We are well aware of the pain and frustration that a
506 backwards-incompatible change to Perl can cause for developers building
507 or maintaining software in Perl. You can be sure that when we deprecate
508 a functionality or syntax, it isn't a choice we make lightly. Sometimes,
509 we choose to deprecate functionality or syntax because it was found to
510 be poorly designed or implemented. Sometimes, this is because they're
511 holding back other features or causing performance problems. Sometimes,
512 the reasons are more complex. Wherever possible, we try to keep deprecated
513 functionality available to developers in its previous form for at least
514 one major release. So long as a deprecated feature isn't actively
515 disrupting our ability to maintain and extend Perl, we'll try to leave
516 it in place as long as possible.
518 The following items are now deprecated:
524 C<suidperl> is no longer part of Perl. It used to provide a mechanism to
525 emulate setuid permission bits on systems that don't support it properly.
528 =item Use of C<:=> to mean an empty attribute list
530 An accident of Perl's parser meant that these constructions were all
537 with the C<:> being treated as the start of an attribute list, which
538 ends before the C<=>. As whitespace is not significant here, all are
539 parsed as an empty attribute list, hence all the above are equivalent
540 to, and better written as
544 because no attribute processing is done for an empty list.
546 As is, this meant that C<:=> cannot be used as a new token, without
547 silently changing the meaning of existing code. Hence that particular
548 form is now deprecated, and will become a syntax error. If it is
549 absolutely necessary to have empty attribute lists (for example,
550 because of a code generator) then avoid the warning by adding a space
553 =item C<< UNIVERSAL->import() >>
555 The method C<< UNIVERSAL->import() >> is now deprecated. Attempting to
556 pass import arguments to a C<use UNIVERSAL> statement will result in a
560 =item Use of "goto" to jump into a construct
562 Using C<goto> to jump from an outer scope into an inner scope is now
563 deprecated. This rare use case was causing problems in the
564 implementation of scopes.
566 =item Custom character names in \N{name} that don't look like names
568 In C<\N{I<name>}>, I<name> can be just about anything. The standard
569 Unicode names have a very limited domain, but a custom name translator
570 could create names that are, for example, made up entirely of punctuation
571 symbols. It is now deprecated to make names that don't begin with an
572 alphabetic character, and aren't alphanumeric or contain other than
573 a very few other characters, namely spaces, dashes, parentheses
574 and colons. Because of the added meaning of C<\N> (See L</C<\N>
575 experimental regex escape>), names that look like curly brace -enclosed
576 quantifiers won't work. For example, C<\N{3,4}> now means to match 3 to
577 4 non-newlines; before a custom name C<3,4> could have been created.
579 =item Deprecated Modules
581 The following modules will be removed from the core distribution in a
582 future release, and should be installed from CPAN instead. Distributions
583 on CPAN which require these should add them to their prerequisites. The
584 core versions of these modules warnings will issue a deprecation warning.
586 If you ship a packaged version of Perl, either alone or as part of a
587 larger system, then you should carefully consider the reprecussions of
588 core module deprecations. You may want to consider shipping your default
589 build of Perl with packages for some or all deprecated modules which
590 install into C<vendor> or C<site> perl library directories. This will
591 inhibit the deprecation warnings.
593 Alternatively, you may want to consider patching F<lib/deprecate.pm>
594 to provide deprecation warnings specific to your packaging system
595 or distribution of Perl, consistent with how your packaging system
596 or distribution manages a staged transition from a release where the
597 installation of a single package provides the given functionality, to
598 a later release where the system administrator needs to know to install
599 multiple packages to get that same functionality.
605 =item L<Pod::Plainer>
611 Switch is buggy and should be avoided. You may find Perl's new
612 C<given>/C<when> feature a suitable replacement. See L<perlsyn/"Switch
613 statements"> for more information.
617 =item Assignment to $[
619 =item Use of the attribute :locked on subroutines
621 =item Use of "locked" with the attributes pragma
623 =item Use of "unique" with the attributes pragma
627 C<Perl_pmflag> is no longer part of Perl's public API. Calling it now
628 generates a deprecation warning, and it will be removed in a future
629 release. Although listed as part of the API, it was never documented,
630 and only ever used in F<toke.c>, and prior to 5.10, F<regcomp.c>. In
631 core, it has been replaced by a static function.
633 =item Numerous Perl 4-era libraries
635 F<termcap.pl>, F<tainted.pl>, F<stat.pl>, F<shellwords.pl>, F<pwd.pl>,
636 F<open3.pl>, F<open2.pl>, F<newgetopt.pl>, F<look.pl>, F<find.pl>,
637 F<finddepth.pl>, F<importenv.pl>, F<hostname.pl>, F<getopts.pl>,
638 F<getopt.pl>, F<getcwd.pl>, F<flush.pl>, F<fastcwd.pl>, F<exceptions.pl>,
639 F<ctime.pl>, F<complete.pl>, F<cacheout.pl>, F<bigrat.pl>, F<bigint.pl>,
640 F<bigfloat.pl>, F<assert.pl>, F<abbrev.pl>, F<dotsh.pl>, and
641 F<timelocal.pl> are all now deprecated. Using them will incur a warning.
646 =head1 Unicode overhaul
648 Perl's developers have made a concerted effort to update Perl to be in
649 sync with the latest Unicode standard. Changes for this include:
651 Perl can now handle every Unicode character property. New documentation,
652 L<perluniprops>, lists all available non-Unihan character properties. By
653 default, perl does not expose Unihan, deprecated or Unicode-internal
654 properties. See below for more details on these; there is also a section
655 in the pod listing them, and explaining why they are not exposed.
657 Perl now fully supports the Unicode compound-style of using C<=>
658 and C<:> in writing regular expressions: C<\p{property=value}> and
659 C<\p{property:value}> (both of which mean the same thing).
661 Perl now fully supports the Unicode loose matching rules for text between
662 the braces in C<\p{...}> constructs. In addition, Perl allows underscores
663 between digits of numbers.
665 Perl now accepts all the Unicode-defined synonyms for properties and
668 C<qr/\X/>, which matches a Unicode logical character, has
669 been expanded to work better with various Asian languages. It
670 now is defined as an I<extended grapheme cluster>. (See
671 L<http://www.unicode.org/reports/tr29/>). Anything matched previously
672 and that made sense will continue to be accepted. Additionally:
678 C<\X> will not break apart a C<S<CR LF>> sequence.
682 C<\X> will now match a sequence which includes the C<ZWJ> and C<ZWNJ>
687 C<\X> will now always match at least one character, including an initial
688 mark. Marks generally come after a base character, but it is possible in
689 Unicode to have them in isolation, and C<\X> will now handle that case,
690 for example at the beginning of a line, or after a C<ZWSP>. And this is
691 the part where C<\X> doesn't match the things that it used to that don't
692 make sense. Formerly, for example, you could have the nonsensical case
697 C<\X> will now match a (Korean) Hangul syllable sequence, and the Thai
698 and Lao exception cases.
702 Otherwise, this change should be transparent for the non-affected
705 C<\p{...}> matches using the Canonical_Combining_Class property were
706 completely broken in previous releases of Perl. They should now work
709 Before Perl 5.12, the Unicode C<Decomposition_Type=Compat> property
710 and a Perl extension had the same name, which led to neither matching
711 all the correct values (with more than 100 mistakes in one, and several
712 thousand in the other). The Perl extension has now been renamed to be
713 C<Decomposition_Type=Noncanonical> (short: C<dt=noncanon>). It has the
714 same meaning as was previously intended, namely the union of all the
715 non-canonical Decomposition types, with Unicode C<Compat> being just
718 C<\p{Decomposition_Type=Canonical}> now includes the Hangul syllables.
720 C<\p{Uppercase}> and C<\p{Lowercase}> now work as the Unicode standard
721 says they should. This means they each match a few more characters than
724 C<\p{Cntrl}> now matches the same characters as C<\p{Control}>. This
725 means it no longer will match Private Use (gc=co), Surrogates (gc=cs),
726 nor Format (gc=cf) code points. The Format code points represent the
727 biggest possible problem. All but 36 of them are either officially
728 deprecated or strongly discouraged from being used. Of those 36, likely
729 the most widely used are the soft hyphen (U+00AD), and BOM, ZWSP, ZWNJ,
730 WJ, and similar characters, plus bidirectional controls.
732 C<\p{Alpha}> now matches the same characters as C<\p{Alphabetic}>. Before
733 5.12, Perl's definition definition included a number of things that aren't
734 really alpha (all marks) while omitting many that were. The definitions
735 of C<\p{Alnum}> and C<\p{Word}> depend on Alpha's definition and have
738 C<\p{Word}> no longer incorrectly matches non-word characters such
741 C<\p{Print}> no longer matches the line control characters: Tab, LF,
742 CR, FF, VT, and NEL. This brings it in line with standards and the
745 C<\p{XDigit}> now matches the same characters as C<\p{Hex_Digit}>. This
746 means that in addition to the characters it currently matches,
747 C<[A-Fa-f0-9]>, it will also match the 22 fullwidth equivalents, for
748 example U+FF10: FULLWIDTH DIGIT ZERO.
750 The Numeric type property has been extended to include the Unihan
753 There is a new Perl extension, the 'Present_In', or simply 'In',
754 property. This is an extension of the Unicode Age property, but
755 C<\p{In=5.0}> matches any code point whose usage has been determined
756 I<as of> Unicode version 5.0. The C<\p{Age=5.0}> only matches code points
757 added in I<precisely> version 5.0.
759 A number of properties now have the correct values for unassigned
760 code points. The affected properties are Bidi_Class, East_Asian_Width,
761 Joining_Type, Decomposition_Type, Hangul_Syllable_Type, Numeric_Type,
764 The Default_Ignorable_Code_Point, ID_Continue, and ID_Start properties
765 are now up to date with current Unicode definitions.
767 Earlier versions of Perl erroneously exposed certain properties that
768 are supposed to be Unicode internal-only. Use of these in regular
769 expressions will now generate, if enabled, a deprecation warning message.
770 The properties are: Other_Alphabetic, Other_Default_Ignorable_Code_Point,
771 Other_Grapheme_Extend, Other_ID_Continue, Other_ID_Start, Other_Lowercase,
772 Other_Math, and Other_Uppercase.
774 It is now possible to change which Unicode properties Perl understands
775 on a per-installation basis. As mentioned above, certain properties
776 are turned off by default. These include all the Unihan properties
777 (which should be accessible via the CPAN module Unicode::Unihan) and any
778 deprecated or Unicode internal-only property that Perl has never exposed.
780 The generated files in the C<lib/unicore/To> directory are now more
781 clearly marked as being stable, directly usable by applications. New hash
782 entries in them give the format of the normal entries, which allows for
783 easier machine parsing. Perl can generate files in this directory for
784 any property, though most are suppressed. You can find instructions
785 for changing which are written in L<perluniprops>.
787 =head1 Modules and Pragmata
789 =head2 New Modules and Pragmata
795 C<autodie> is a new lexically-scoped alternative for the C<Fatal> module.
796 The bundled version is 2.06_01. Note that in this release, using a string
797 eval when C<autodie> is in effect can cause the autodie behaviour to leak
798 into the surrounding scope. See L<autodie/"BUGS"> for more details.
800 Version 2.06_01 has been added to the Perl core.
802 =item C<Compress::Raw::Bzip2>
804 Version 2.024 has been added to the Perl core.
808 C<overloading> allows you to lexically disable or enable overloading
809 for some or all operations.
811 Version 0.001 has been added to the Perl core.
815 C<parent> establishes an ISA relationship with base classes at compile
816 time. It provides the key feature of C<base> without further unwanted
819 Version 0.223 has been added to the Perl core.
821 =item C<Parse::CPAN::Meta>
823 Version 1.40 has been added to the Perl core.
827 Version 1.03 has been added to the Perl core.
831 Version 2.4 has been added to the Perl core.
833 =item C<XS::APItest::KeywordRPN>
835 Version 0.003 has been added to the Perl core.
839 =head2 Updated Pragmata
845 Upgraded from version 2.13 to 2.15.
849 Upgraded from version 0.22 to 0.23.
853 C<charnames> now contains the Unicode F<NameAliases.txt> database file.
854 This has the effect of adding some extra C<\N> character names that
855 formerly wouldn't have been recognised; for example, C<"\N{LATIN CAPITAL
858 Upgraded from version 1.06 to 1.07.
862 Upgraded from version 1.13 to 1.20.
866 C<diagnostics> now supports %.0f formatting internally.
868 C<diagnostics> no longer suppresses C<Use of uninitialized value in range
869 (or flip)> warnings. [perl #71204]
871 Upgraded from version 1.17 to 1.19.
875 In C<feature>, the meaning of the C<:5.10> and C<:5.10.X> feature
876 bundles has changed slightly. The last component, if any (i.e. C<X>) is
877 simply ignored. This is predicated on the assumption that new features
878 will not, in general, be added to maintenance releases. So C<:5.10>
879 and C<:5.10.X> have identical effect. This is a change to the behaviour
880 documented for 5.10.0.
882 C<feature> now includes the C<unicode_strings> feature:
884 use feature "unicode_strings";
886 This pragma turns on Unicode semantics for the case-changing operations
887 (C<uc>, C<lc>, C<ucfirst>, C<lcfirst>) on strings that don't have the
888 internal UTF-8 flag set, but that contain single-byte characters between
891 Upgraded from version 1.11 to 1.16.
895 C<less> now includes the C<stash_name> method to allow subclasses of
896 C<less> to pick where in %^H to store their stash.
898 Upgraded from version 0.02 to 0.03.
902 Upgraded from version 0.5565 to 0.62.
906 C<mro> is now implemented as an XS extension. The documented interface has
907 not changed. Code relying on the implementation detail that some C<mro::>
908 methods happened to be available at all times gets to "keep both pieces".
910 Upgraded from version 1.00 to 1.02.
914 C<overload> now allow overloading of 'qr'.
916 Upgraded from version 1.06 to 1.10.
920 Upgraded from version 1.67 to 1.75.
922 =item C<threads::shared>
924 Upgraded from version 1.14 to 1.32.
928 C<version> now has support for L</Version number formats> as described
929 earlier in this document and in its own documentation.
931 Upgraded from version 0.74 to 0.82.
935 C<warnings> has a new C<warnings::fatal_enabled()> function. It also
936 includes a new C<illegalproto> warning category. See also L</New or
937 Changed Diagnostics> for this change.
939 Upgraded from version 1.06 to 1.09.
943 =head2 Updated Modules
947 =item C<Archive::Extract>
949 Upgraded from version 0.24 to 0.38.
951 =item C<Archive::Tar>
953 Upgraded from version 1.38 to 1.54.
955 =item C<Attribute::Handlers>
957 Upgraded from version 0.79 to 0.87.
961 Upgraded from version 5.63 to 5.70.
965 Upgraded from version 0.74 to 0.78.
969 Upgraded from version 1.05 to 1.12.
973 Upgraded from version 0.83 to 0.96.
977 Upgraded from version 1.09 to 1.11_01.
981 Upgraded from version 3.29 to 3.48.
985 Upgraded from version 0.33 to 0.36.
987 NOTE: C<Class::ISA> is deprecated and may be removed from a future
990 =item C<Compress::Raw::Zlib>
992 Upgraded from version 2.008 to 2.024.
996 Upgraded from version 1.9205 to 1.94_56.
1000 Upgraded from version 0.84 to 0.90.
1002 =item C<CPANPLUS::Dist::Build>
1004 Upgraded from version 0.06_02 to 0.46.
1006 =item C<Data::Dumper>
1008 Upgraded from version 2.121_14 to 2.125.
1012 Upgraded from version 1.816_1 to 1.820.
1014 =item C<Devel::PPPort>
1016 Upgraded from version 3.13 to 3.19.
1020 Upgraded from version 1.15 to 1.16.
1022 =item C<Digest::MD5>
1024 Upgraded from version 2.36_01 to 2.39.
1026 =item C<Digest::SHA>
1028 Upgraded from version 5.45 to 5.47.
1032 Upgraded from version 2.23 to 2.39.
1036 Upgraded from version 5.62 to 5.64_01.
1038 =item C<ExtUtils::CBuilder>
1040 Upgraded from version 0.21 to 0.27.
1042 =item C<ExtUtils::Command>
1044 Upgraded from version 1.13 to 1.16.
1046 =item C<ExtUtils::Constant>
1048 Upgraded from version 0.2 to 0.22.
1050 =item C<ExtUtils::Install>
1052 Upgraded from version 1.44 to 1.55.
1054 =item C<ExtUtils::MakeMaker>
1056 Upgraded from version 6.42 to 6.56.
1058 =item C<ExtUtils::Manifest>
1060 Upgraded from version 1.51_01 to 1.57.
1062 =item C<ExtUtils::ParseXS>
1064 Upgraded from version 2.18_02 to 2.21.
1066 =item C<File::Fetch>
1068 Upgraded from version 0.14 to 0.24.
1072 Upgraded from version 2.04 to 2.08_01.
1076 Upgraded from version 0.18 to 0.22.
1078 =item C<Filter::Simple>
1080 Upgraded from version 0.82 to 0.84.
1082 =item C<Filter::Util::Call>
1084 Upgraded from version 1.07 to 1.08.
1086 =item C<Getopt::Long>
1088 Upgraded from version 2.37 to 2.38.
1092 Upgraded from version 1.23_01 to 1.25_02.
1096 Upgraded from version 1.07 to 1.10.
1100 Upgraded from version 0.40_1 to 0.54.
1104 Upgraded from version 1.05 to 2.01.
1106 =item C<Locale::Maketext>
1108 Upgraded from version 1.12 to 1.14.
1110 =item C<Locale::Maketext::Simple>
1112 Upgraded from version 0.18 to 0.21.
1114 =item C<Log::Message>
1116 Upgraded from version 0.01 to 0.02.
1118 =item C<Log::Message::Simple>
1120 Upgraded from version 0.04 to 0.06.
1122 =item C<Math::BigInt>
1124 Upgraded from version 1.88 to 1.89_01.
1126 =item C<Math::BigInt::FastCalc>
1128 Upgraded from version 0.16 to 0.19.
1130 =item C<Math::BigRat>
1132 Upgraded from version 0.21 to 0.24.
1134 =item C<Math::Complex>
1136 Upgraded from version 1.37 to 1.56.
1140 Upgraded from version 1.01_02 to 1.01_03.
1142 =item C<MIME::Base64>
1144 Upgraded from version 3.07_01 to 3.08.
1146 =item C<Module::Build>
1148 Upgraded from version 0.2808_01 to 0.3603.
1150 =item C<Module::CoreList>
1152 Upgraded from version 2.12 to 2.29.
1154 =item C<Module::Load>
1156 Upgraded from version 0.12 to 0.16.
1158 =item C<Module::Load::Conditional>
1160 Upgraded from version 0.22 to 0.34.
1162 =item C<Module::Loaded>
1164 Upgraded from version 0.01 to 0.06.
1166 =item C<Module::Pluggable>
1168 Upgraded from version 3.6 to 3.9.
1172 Upgraded from version 2.33 to 2.36.
1176 Upgraded from version 0.60_01 to 0.64.
1178 =item C<Object::Accessor>
1180 Upgraded from version 0.32 to 0.36.
1182 =item C<Package::Constants>
1184 Upgraded from version 0.01 to 0.02.
1188 Upgraded from version 1.04 to 1.06.
1190 =item C<Pod::Parser>
1192 Upgraded from version 1.35 to 1.37.
1194 =item C<Pod::Perldoc>
1196 Upgraded from version 3.14_02 to 3.15_02.
1198 =item C<Pod::Plainer>
1200 Upgraded from version 0.01 to 1.02.
1202 NOTE: C<Pod::Plainer> is deprecated and may be removed from a future
1205 =item C<Pod::Simple>
1207 Upgraded from version 3.05 to 3.13.
1211 Upgraded from version 2.12 to 2.22.
1215 Upgraded from version 1.11 to 1.17.
1219 Upgraded from version 2.18 to 2.22.
1223 Upgraded from version 2.13 to 2.16.
1225 NOTE: C<Switch> is deprecated and may be removed from a future version
1228 =item C<Sys::Syslog>
1230 Upgraded from version 0.22 to 0.27.
1232 =item C<Term::ANSIColor>
1234 Upgraded from version 1.12 to 2.02.
1238 Upgraded from version 0.18 to 0.20.
1242 Upgraded from version 1.25 to 1.25_02.
1244 =item C<Test::Harness>
1246 Upgraded from version 2.64 to 3.17.
1248 =item C<Test::Simple>
1250 Upgraded from version 0.72 to 0.94.
1252 =item C<Text::Balanced>
1254 Upgraded from version 2.0.0 to 2.02.
1256 =item C<Text::ParseWords>
1258 Upgraded from version 3.26 to 3.27.
1260 =item C<Text::Soundex>
1262 Upgraded from version 3.03 to 3.03_01.
1264 =item C<Thread::Queue>
1266 Upgraded from version 2.00 to 2.11.
1268 =item C<Thread::Semaphore>
1270 Upgraded from version 2.01 to 2.09.
1272 =item C<Tie::RefHash>
1274 Upgraded from version 1.37 to 1.38.
1276 =item C<Time::HiRes>
1278 Upgraded from version 1.9711 to 1.9719.
1280 =item C<Time::Local>
1282 Upgraded from version 1.18 to 1.1901_01.
1284 =item C<Time::Piece>
1286 Upgraded from version 1.12 to 1.15.
1288 =item C<Unicode::Collate>
1290 Upgraded from version 0.52 to 0.52_01.
1292 =item C<Unicode::Normalize>
1294 Upgraded from version 1.02 to 1.03.
1298 Upgraded from version 0.34 to 0.39.
1300 =item C<Win32API::File>
1302 Upgraded from version 0.1001_01 to 0.1101.
1306 Upgraded from version 0.08 to 0.10.
1310 =head2 Removed Modules and Pragmata
1316 Removed from the Perl core. Prior version was 1.02.
1318 =item C<CPAN::API::HOWTO>
1320 Removed from the Perl core. Prior version was 'undef'.
1322 =item C<CPAN::DeferedCode>
1324 Removed from the Perl core. Prior version was 5.50.
1326 =item C<CPANPLUS::inc>
1328 Removed from the Perl core. Prior version was 'undef'.
1332 Removed from the Perl core. Prior version was 1.03.
1334 =item C<ExtUtils::MakeMaker::bytes>
1336 Removed from the Perl core. Prior version was 6.42.
1338 =item C<ExtUtils::MakeMaker::vmsish>
1340 Removed from the Perl core. Prior version was 6.42.
1344 Removed from the Perl core. Prior version was 2.3.
1346 =item C<Test::Harness::Assert>
1348 Removed from the Perl core. Prior version was 0.02.
1350 =item C<Test::Harness::Iterator>
1352 Removed from the Perl core. Prior version was 0.02.
1354 =item C<Test::Harness::Point>
1356 Removed from the Perl core. Prior version was 0.01.
1358 =item C<Test::Harness::Results>
1360 Removed from the Perl core. Prior version was 0.01.
1362 =item C<Test::Harness::Straps>
1364 Removed from the Perl core. Prior version was 0.26_01.
1366 =item C<Test::Harness::Util>
1368 Removed from the Perl core. Prior version was 0.01.
1372 Removed from the Perl core. Prior version was 1.1.
1376 =head2 Deprecated Modules and Pragmata
1378 See L</Deprecated Modules> above.
1381 =head1 Documentation
1383 =head2 New Documentation
1389 L<perlhaiku> contains instructions on how to build perl for the Haiku
1394 L<perlmroapi> describes the new interface for pluggable Method Resolution
1399 L<perlperf>, by Richard Foley, provides an introduction to the use of
1400 performance and optimization techniques which can be used with particular
1401 reference to perl programs.
1405 L<perlrepository> describes how to access the perl source using the I<git>
1406 version control system.
1410 L<perlpolicy> extends the "Social contract about contributed modules" into
1411 the beginnings of a document on Perl porting policies.
1415 =head2 Changes to Existing Documentation
1423 The various large F<Changes*> files (which listed every change made
1424 to perl over the last 18 years) have been removed, and replaced by a
1425 small file, also called F<Changes>, which just explains how that same
1426 information may be extracted from the git version control system.
1430 F<Porting/patching.pod> has been deleted, as it mainly described
1431 interacting with the old Perforce-based repository, which is now obsolete.
1432 Information still relevant has been moved to L<perlrepository>.
1437 The syntax C<unless (EXPR) BLOCK else BLOCK> is now documented as valid,
1438 as is the syntax C<unless (EXPR) BLOCK elsif (EXPR) BLOCK ... else
1439 BLOCK>, although actually using the latter may not be the best idea for
1440 the readability of your source code.
1445 Documented -X overloading.
1449 Documented that C<when()> treats specially most of the filetest operators
1453 Documented C<when> as a syntax modifier.
1457 Eliminated "Old Perl threads tutorial", which described 5005 threads.
1459 F<pod/perlthrtut.pod> is the same material reworked for ithreads.
1463 Correct previous documentation: v-strings are not deprecated
1465 With version objects, we need them to use MODULE VERSION syntax. This
1466 patch removes the deprecation notice.
1470 Security contact information is now part of L<perlsec>.
1474 A significant fraction of the core documentation has been updated to
1475 clarify the behavior of Perl's Unicode handling.
1477 Much of the remaining core documentation has been reviewed and edited
1478 for clarity, consistent use of language, and to fix the spelling of Tom
1479 Christiansen's name.
1483 The Pod specification (L<perlpodspec>) has been updated to bring the
1484 specification in line with modern usage already supported by most Pod
1485 systems. A parameter string may now follow the format name in a
1486 "begin/end" region. Links to URIs with a text description are now
1487 allowed. The usage of C<LE<lt>"section"E<gt>> has been marked as
1492 L<if.pm|if> has been documented in L<perlfunc/use> as a means to get
1493 conditional loading of modules despite the implicit BEGIN block around
1498 The documentation for C<$1> in perlvar.pod has been clarified.
1502 C<\N{U+I<wide hex char>}> is now documented.
1506 =head1 Selected Performance Enhancements
1512 A new internal cache means that C<isa()> will often be faster.
1516 The implementation of C<C3> Method Resolution Order has been
1517 optimised - linearisation for classes with single inheritance is 40%
1518 faster. Performance for multiple inheritance is unchanged.
1522 Under C<use locale>, the locale-relevant information is now cached on
1523 read-only values, such as the list returned by C<keys %hash>. This makes
1524 operations such as C<sort keys %hash> in the scope of C<use locale>
1529 Empty C<DESTROY> methods are no longer called.
1533 C<Perl_sv_utf8_upgrade()> is now faster.
1537 C<keys> on empty hash is now faster.
1541 C<if (%foo)> has been optimized to be faster than C<if (keys %foo)>.
1545 The string repetition operator (C<$str x $num>) is now several times
1546 faster when C<$str> has length one or C<$num> is large.
1550 Reversing an array to itself (as in C<@a = reverse @a>) in void context
1551 now happens in-place and is several orders of magnitude faster than
1552 it used to be. It will also preserve non-existent elements whenever
1553 possible, i.e. for non magical arrays or tied arrays with C<EXISTS>
1554 and C<DELETE> methods.
1558 =head1 Installation and Configuration Improvements
1564 L<perlapi>, L<perlintern>, L<perlmodlib> and L<perltoc> are now all
1565 generated at build time, rather than being shipped as part of the release.
1569 If C<vendorlib> and C<vendorarch> are the same, then they are only added
1574 C<$Config{usedevel}> and the C-level C<PERL_USE_DEVEL> are now defined if
1575 perl is built with C<-Dusedevel>.
1579 F<Configure> will enable use of C<-fstack-protector>, to provide protection
1580 against stack-smashing attacks, if the compiler supports it.
1584 F<Configure> will now determine the correct prototypes for re-entrant
1585 functions and for C<gconvert> if you are using a C++ compiler rather
1590 On Unix, if you build from a tree containing a git repository, the
1591 configuration process will note the commit hash you have checked out, for
1592 display in the output of C<perl -v> and C<perl -V>. Unpushed local commits
1593 are automatically added to the list of local patches displayed by
1598 Perl now supports SystemTap's C<dtrace> compatibility layer and an
1599 issue with linking C<miniperl> has been fixed in the process.
1603 perldoc now uses C<less -R> instead of C<less> for improved behaviour
1604 in the face of C<groff>'s new usage of ANSI escape codes.
1609 C<perl -V> now reports use of the compile-time options C<USE_PERL_ATOF> and
1610 C<USE_ATTRIBUTES_FOR_PERLIO>.
1614 As part of the flattening of F<ext>, all extensions on all platforms are
1615 built by F<make_ext.pl>. This replaces the Unix-specific
1616 F<ext/util/make_ext>, VMS-specific F<make_ext.com> and Win32-specific
1617 F<win32/buildext.pl>.
1621 =head1 Internal Changes
1623 Each release of Perl sees numerous internal changes which shouldn't
1624 affect day to day usage but may still be notable for developers working
1625 with Perl's source code.
1631 The J.R.R. Tolkien quotes at the head of C source file have been checked
1632 and proper citations added, thanks to a patch from Tom Christiansen.
1636 The internal structure of the dual-life modules traditionally found in
1637 the F<lib/> and F<ext/> directories y in the perl source has changed
1638 significantly. Where possible, dual-lifed modules have been extracted
1639 from F<lib/> and F<ext/>.
1641 Dual-lifed modules maintained by Perl's developers as part of the Perl
1642 core now live in F<dist/>. Dual-lifed modules maintained primarily on
1643 CPAN now live in F<cpan/>. When reporting a bug in a module located
1644 under F<cpan/>, please send your bug report directly to the module's
1645 bug tracker or author, rather than Perl's bug tracker.
1649 C<\N{...}> now compiles better, always forces UTF-8 internal representation
1651 Perl's developers have fixed several problems with the recognition of
1652 C<\N{...}> constructs. As part of this, perl will store any scalar
1653 or regex containing C<\N{I<name>}> or C<\N{U+I<wide hex char>}> in its
1654 definition in UTF-8 format. (This was true previously for all occurences
1655 of C<\N{I<name>}> that did not use a custom translator, but now it's
1660 Perl_magic_setmglob now knows about globs, fixing RT #71254.
1664 C<SVt_RV> no longer exists. RVs are now stored in IVs.
1668 C<Perl_vcroak()> now accepts a null first argument. In addition, a full
1669 audit was made of the "not NULL" compiler annotations, and those for
1670 several other internal functions were corrected.
1674 New macros C<dSAVEDERRNO>, C<dSAVE_ERRNO>, C<SAVE_ERRNO>, C<RESTORE_ERRNO>
1675 have been added to formalise the temporary saving of the C<errno>
1680 The function C<Perl_sv_insert_flags> has been added to augment
1685 The function C<Perl_newSV_type(type)> has been added, equivalent to
1686 C<Perl_newSV()> followed by C<Perl_sv_upgrade(type)>.
1690 The function C<Perl_newSVpvn_flags()> has been added, equivalent to
1691 C<Perl_newSVpvn()> and then performing the action relevant to the flag.
1693 Two flag bits are currently supported.
1699 C<SVf_UTF8> will call C<SvUTF8_on()> for you. (Note that this does
1700 not convert an sequence of ISO 8859-1 characters to UTF-8). A wrapper,
1701 C<newSVpvn_utf8()> is available for this.
1705 C<SVs_TEMP> now calls C<Perl_sv_2mortal()> on the new SV.
1709 There is also a wrapper that takes constant strings, C<newSVpvs_flags()>.
1713 The function C<Perl_croak_xs_usage> has been added as a wrapper to
1718 Perl now exports the functions C<PerlIO_find_layer> and C<PerlIO_list_alloc>.
1722 C<PL_na> has been exterminated from the core code, replaced by local
1723 STRLEN temporaries, or C<*_nolen()> calls. Either approach is faster than
1724 C<PL_na>, which is a pointer dereference into the interpreter structure
1725 under ithreads, and a global variable otherwise.
1729 C<Perl_mg_free()> used to leave freed memory accessible via C<SvMAGIC()>
1730 on the scalar. It now updates the linked list to remove each piece of
1731 magic as it is freed.
1735 Under ithreads, the regex in C<PL_reg_curpm> is now reference
1736 counted. This eliminates a lot of hackish workarounds to cope with it
1737 not being reference counted.
1741 C<Perl_mg_magical()> would sometimes incorrectly turn on C<SvRMAGICAL()>.
1742 This has been fixed.
1746 The I<public> IV and NV flags are now not set if the string value has
1747 trailing "garbage". This behaviour is consistent with not setting the
1748 public IV or NV flags if the value is out of range for the type.
1752 Uses of C<Nullav>, C<Nullcv>, C<Nullhv>, C<Nullop>, C<Nullsv> etc have
1753 been replaced by C<NULL> in the core code, and non-dual-life modules,
1754 as C<NULL> is clearer to those unfamiliar with the core code.
1758 A macro C<MUTABLE_PTR(p)> has been added, which on (non-pedantic) gcc will
1759 not cast away C<const>, returning a C<void *>. Macros C<MUTABLE_SV(av)>,
1760 C<MUTABLE_SV(cv)> etc build on this, casting to C<AV *> etc without
1761 casting away C<const>. This allows proper compile-time auditing of
1762 C<const> correctness in the core, and helped picked up some errors
1767 Macros C<mPUSHs()> and C<mXPUSHs()> have been added, for pushing SVs on the
1768 stack and mortalizing them.
1772 Use of the private structure C<mro_meta> has changed slightly. Nothing
1773 outside the core should be accessing this directly anyway.
1777 A new tool, F<Porting/expand-macro.pl> has been added, that allows you
1778 to view how a C preprocessor macro would be expanded when compiled.
1779 This is handy when trying to decode the macro hell that is the perl
1786 =head2 Testing improvements
1790 =item Parallel tests
1792 The core distribution can now run its regression tests in parallel on
1793 Unix-like platforms. Instead of running C<make test>, set C<TEST_JOBS> in
1794 your environment to the number of tests to run in parallel, and run
1795 C<make test_harness>. On a Bourne-like shell, this can be done as
1797 TEST_JOBS=3 make test_harness # Run 3 tests in parallel
1799 An environment variable is used, rather than parallel make itself, because
1800 L<TAP::Harness> needs to be able to schedule individual non-conflicting test
1801 scripts itself, and there is no standard interface to C<make> utilities to
1802 interact with their job schedulers.
1804 Note that currently some test scripts may fail when run in parallel (most
1805 notably C<ext/IO/t/io_dir.t>). If necessary run just the failing scripts
1806 again sequentially and see if the failures go away.
1808 =item Test harness flexibility
1810 It's now possible to override C<PERL5OPT> and friends in F<t/TEST>
1814 Several tests that have the potential to hang forever if they fail now
1815 incorporate a "watchdog" functionality that will kill them after a timeout,
1816 which helps ensure that C<make test> and C<make test_harness> run to
1817 completion automatically.
1824 Perl's developers have added a number of new tests to the core.
1825 In addition to the items listed below, many modules updated from CPAN
1826 incorporate new tests.
1832 Significant cleanups to core tests to ensure that language and
1833 interpreter features are not used before they're tested.
1837 C<make test_porting> now runs a number of important pre-commit checks
1838 which might be of use to anyone working on the Perl core.
1842 F<t/porting/podcheck.t> automatically checks the well-formedness of
1843 POD found in all .pl, .pm and .pod files in the F<MANIFEST>, other than in
1844 dual-lifed modules which are primarily maintained outside the Perl core.
1848 F<t/porting/manifest.t> now tests that all files listed in MANIFEST
1853 F<t/op/while_readdir.t> tests that a bare readdir in while loop sets $_.
1857 F<t/comp/retainedlines.t> checks that the debugger can retain source
1862 F<t/io/perlio_fail.t> checks that bad layers fail.
1866 F<t/io/perlio_leaks.t> checks that PerlIO layers are not leaking.
1870 F<t/io/perlio_open.t> checks that certain special forms of open work.
1874 F<t/io/perlio.t> includes general PerlIO tests.
1878 F<t/io/pvbm.t> checks that there is no unexpected interaction between
1879 the internal types C<PVBM> and C<PVGV>.
1883 F<t/mro/package_aliases.t> checks that mro works properly in the presence
1884 of aliased packages.
1888 F<t/op/dbm.t> tests C<dbmopen> and C<dbmclose>.
1892 F<t/op/index_thr.t> tests the interaction of C<index> and threads.
1896 F<t/op/pat_thr.t> tests the interaction of esoteric patterns and threads.
1900 F<t/op/qr_gc.t> tests that C<qr> doesn't leak.
1904 F<t/op/reg_email_thr.t> tests the interaction of regex recursion and threads.
1908 F<t/op/regexp_qr_embed_thr.t> tests the interaction of patterns with
1909 embedded C<qr//> and threads.
1913 F<t/op/regexp_unicode_prop.t> tests Unicode properties in regular
1918 F<t/op/regexp_unicode_prop_thr.t> tests the interaction of Unicode
1919 properties and threads.
1923 F<t/op/reg_nc_tie.t> tests the tied methods of C<Tie::Hash::NamedCapture>.
1927 F<t/op/reg_posixcc.t> checks that POSIX character classes behave
1932 F<t/op/re.t> checks that exportable C<re> functions in F<universal.c> work.
1936 F<t/op/setpgrpstack.t> checks that C<setpgrp> works.
1940 F<t/op/substr_thr.t> tests the interaction of C<substr> and threads.
1944 F<t/op/upgrade.t> checks that upgrading and assigning scalars works.
1948 F<t/uni/lex_utf8.t> checks that Unicode in the lexer works.
1952 F<t/uni/tie.t> checks that Unicode and C<tie> work.
1956 F<t/comp/final_line_num.t> tests whether line numbers are correct at EOF
1960 F<t/comp/form_scope.t> tests format scoping.
1964 F<t/comp/line_debug.t> tests whether C<< @{"_<$file"} >> works.
1968 F<t/op/filetest_t.t> tests if -t file test works.
1972 F<t/op/qr.t> tests C<qr>.
1976 F<t/op/utf8cache.t> tests malfunctions of the utf8 cache.
1980 F<t/re/uniprops.t> test unicodes C<\p{}> regex constructs.
1984 F<t/op/filehandle.t> tests some suitably portable filetest operators
1985 to check that they work as expected, particularly in the light of some
1986 internal changes made in how filehandles are blessed.
1990 F<t/op/time_loop.t> tests that unix times greater than C<2**63>, which
1991 can now be handed to C<gmtime> and C<localtime>, do not cause an internal
1992 overflow or an excessively long loop.
1997 =head1 New or Changed Diagnostics
1999 =head2 New Diagnostics
2005 SV allocation tracing has been added to the diagnostics enabled by C<-Dm>.
2006 The tracing can alternatively output via the C<PERL_MEM_LOG> mechanism, if
2007 that was enabled when the F<perl> binary was compiled.
2011 Smartmatch resolution tracing has been added as a new diagnostic. Use
2012 C<-DM> to enable it.
2016 A new debugging flag C<-DB> now dumps subroutine definitions, leaving
2017 C<-Dx> for its original purpose of dumping syntax trees.
2021 Perl 5.12 provides a number of new diagnostic messages to help you write
2022 better code. See L<perldiag> for details of these new messages.
2028 C<Bad plugin affecting keyword '%s'>
2032 C<gmtime(%.0f) too large>
2036 C<Lexing code attempted to stuff non-Latin-1 character into Latin-1 input>
2040 C<Lexing code internal error (%s)>
2044 C<localtime(%.0f) too large>
2048 C<Overloaded dereference did not return a reference>
2052 C<Overloaded qr did not return a REGEXP>
2056 C<Perl_pmflag() is deprecated, and will be removed from the XS API>
2060 C<lvalue attribute ignored after the subroutine has been defined>
2062 This new warning is issued when one attempts to mark a subroutine as
2063 lvalue after it has been defined.
2067 Perl now warns you if C<++> or C<--> are unable to change the value
2068 because it's beyond the limit of representation.
2070 This uses a new warnings category: "imprecision".
2074 C<lc>, C<uc>, C<lcfirst>, and C<ucfirst> warn when passed undef.
2078 C<Show constant in "Useless use of a constant in void context">
2082 C<Prototype after '%s'>
2086 C<panic: sv_chop %s>
2088 This new fatal error occurs when the C routine C<Perl_sv_chop()> was
2089 passed a position that is not within the scalar's string buffer. This
2090 could be caused by buggy XS code, and at this point recovery is not
2096 The fatal error C<Malformed UTF-8 returned by \N> is now produced if the
2097 C<charnames> handler returns malformed UTF-8.
2101 If an unresolved named character or sequence was encountered when
2102 compiling a regex pattern then the fatal error C<\N{NAME} must be resolved
2103 by the lexer> is now produced. This can happen, for example, when using a
2104 single-quotish context like C<$re = '\N{SPACE}'; /$re/;>. See L<perldiag>
2105 for more examples of how the lexer can get bypassed.
2109 C<Invalid hexadecimal number in \N{U+...}> is a new fatal error
2110 triggered when the character constant represented by C<...> is not a
2111 valid hexadecimal number.
2115 The new meaning of C<\N> as C<[^\n]> is not valid in a bracketed character
2116 class, just like C<.> in a character class loses its special meaning,
2117 and will cause the fatal error C<\N in a character class must be a named
2118 character: \N{...}>.
2122 The rules on what is legal for the C<...> in C<\N{...}> have been
2123 tightened up so that unless the C<...> begins with an alphabetic
2124 character and continues with a combination of alphanumerics, dashes,
2125 spaces, parentheses or colons then the warning C<Deprecated character(s)
2126 in \N{...} starting at '%s'> is now issued.
2130 The warning C<Using just the first characters returned by \N{}> will
2131 be issued if the C<charnames> handler returns a sequence of characters
2132 which exceeds the limit of the number of characters that can be used. The
2133 message will indicate which characters were used and which were discarded.
2139 =head2 Changed Diagnostics
2141 A number of existing diagnostic messages have been improved or corrected:
2147 A new warning category C<illegalproto> allows finer-grained control of
2148 warnings around function prototypes.
2154 =item C<Illegal character in prototype for %s : %s>
2156 =item C<Prototype after '%c' for %s : %s>
2160 have been moved from the C<syntax> top-level warnings category into a new
2161 first-level category, C<illegalproto>. These two warnings are currently
2162 the only ones emitted during parsing of an invalid/illegal prototype,
2165 no warnings 'illegalproto';
2167 to suppress only those, but not other syntax-related warnings. Warnings
2168 where prototypes are changed, ignored, or not met are still in the
2169 C<prototype> category as before.
2173 C<Deep recursion on subroutine "%s">
2175 It is now possible to change the depth threshold for this warning from the
2176 default of 100, by recompiling the F<perl> binary, setting the C
2177 pre-processor macro C<PERL_SUB_DEPTH_WARN> to the desired value.
2181 C<Illegal character in prototype> warning is now more precise
2182 when reporting illegal characters after _
2186 mro merging error messages are now very similar to those produced by
2191 Amelioration of the error message "Unrecognized character %s in column %d"
2193 Changes the error message to "Unrecognized character %s; marked by E<lt>--
2194 HERE after %sE<lt>-- HERE near column %d". This should make it a little
2195 simpler to spot and correct the suspicious character.
2199 Perl now explicitly points to C<$.> when it causes an uninitialized
2200 warning for ranges in scalar context.
2204 C<split> now warns when called in void context.
2208 C<printf>-style functions called with too few arguments will now issue the
2209 warning C<"Missing argument in %s"> [perl #71000]
2213 Perl now properly returns a syntax error instead of segfaulting
2214 if C<each>, C<keys>, or C<values> is used without an argument.
2218 C<tell()> now fails properly if called without an argument and when no
2219 previous file was read.
2221 C<tell()> now returns C<-1>, and sets errno to C<EBADF>, thus restoring
2222 the 5.8.x behaviour.
2226 C<overload> no longer implicitly unsets fallback on repeated 'use
2231 POSIX::strftime() can now handle Unicode characters in the format string.
2235 The C<syntax> category was removed from 5 warnings that should only be in
2240 Three fatal C<pack>/C<unpack> error messages have been normalized to
2245 C<Unicode character is illegal> has been rephrased to be more accurate
2247 It now reads C<Unicode non-character is illegal in interchange> and the
2248 perldiag documentation has been expanded a bit.
2252 Currently, all but the first of the several characters that the
2253 C<charnames> handler may return are discarded when used in a regular
2254 expression pattern bracketed character class. If this happens then the
2255 warning C<Using just the first character returned by \N{} in character
2256 class> will be issued.
2260 The warning C<Missing right brace on \N{} or unescaped left brace after
2261 \N. Assuming the latter> will be issued if Perl encounters a C<\N{>
2262 but doesn't find a matching C<}>. In this case Perl doesn't know if it
2263 was mistakenly omitted, or if "match non-newline" followed by "match
2264 a C<{>" was desired. It assumes the latter because that is actually a
2265 valid interpretation as written, unlike the other case. If you meant
2266 the former, you need to add the matching right brace. If you did mean
2267 the latter, you can silence this warning by writing instead C<\N\{>.
2271 C<gmtime> and C<localtime> called with numbers smaller than they can
2272 reliably handle will now issue the warnings C<gmtime(%.0f) too small>
2273 and C<localtime(%.0f) too small>.
2277 The following diagnostic messages have been removed:
2287 C<Can't locate package %s for the parents of %s>
2289 In general this warning it only got produced in
2290 conjunction with other warnings, and removing it allowed an ISA lookup
2291 optimisation to be added.
2295 C<v-string in use/require is non-portable>
2299 =head1 Utility Changes
2305 F<h2ph> now looks in C<include-fixed> too, which is a recent addition
2306 to gcc's search path.
2310 F<h2xs> no longer incorrectly treats enum values like macros.
2311 It also now handles C++ style comments (C<//>) properly in enums.
2315 F<perl5db.pl> now supports C<LVALUE> subroutines. Additionally, the
2316 debugger now correctly handles proxy constant subroutines, and
2321 F<perlbug> now uses C<%Module::CoreList::bug_tracker> to print out
2322 upstream bug tracker URLs. If a user identifies a particular module
2323 as the topic of their bug report and we're able to divine the URL for
2324 its upstream bug tracker, perlbug now provide a message to the user
2325 explaining that the core copies the CPAN version directly, and provide
2326 the URL for reporting the bug directly to the upstream author.
2328 F<perlbug> no longer reports "Message sent" when it hasn't actually sent
2333 F<perlthanks> is a new utility for sending non-bug-reports to the
2334 authors and maintainers of Perl. Getting nothing but bug reports can
2335 become a bit demoralising. If Perl 5.12 works well for you, please try
2336 out F<perlthanks>. It will make the developers smile.
2340 Perl's developers have fixed bugs in F<a2p> having to do with the
2341 C<match()> operator in list context. Additionally, F<a2p> no longer
2342 generates code that uses the C<$[> variable.
2346 =head1 Selected Bug Fixes
2352 U+0FFFF is now a legal character in regular expressions.
2356 pp_qr now always returns a new regexp SV. Resolves RT #69852.
2358 Instead of returning a(nother) reference to the (pre-compiled) regexp
2359 in the optree, use reg_temp_copy() to create a copy of it, and return a
2360 reference to that. This resolves issues about Regexp::DESTROY not being
2361 called in a timely fashion (the original bug tracked by RT #69852), as
2362 well as bugs related to blessing regexps, and of assigning to regexps,
2363 as described in correspondence added to the ticket.
2365 It transpires that we also need to undo the SvPVX() sharing when ithreads
2366 cloning a Regexp SV, because mother_re is set to NULL, instead of a
2367 cloned copy of the mother_re. This change might fix bugs with regexps
2368 and threads in certain other situations, but as yet neither tests nor
2369 bug reports have indicated any problems, so it might not actually be an
2370 edge case that it's possible to reach.
2374 Several compilation errors and segfaults when perl was built with C<-Dmad>
2379 Fixes for lexer API changes in 5.11.2 which broke NYTProf's savesrc option.
2383 C<-t> should only return TRUE for file handles connected to a TTY
2385 The Microsoft C version of C<isatty()> returns TRUE for all character mode
2386 devices, including the F</dev/null>-style "nul" device and printers like
2391 Fixed a regression caused by commit fafafbaf which caused a panic during
2392 parameter passing [perl #70171]
2396 On systems which in-place edits without backup files, -i'*' now works as
2397 the documentation says it does [perl #70802]
2401 Saving and restoring magic flags no longer loses readonly flag.
2405 The malformed syntax C<grep EXPR LIST> (note the missing comma) no longer
2406 causes abrupt and total failure.
2410 Regular expressions compiled with C<qr{}> literals properly set C<$'> when
2415 Using named subroutines with C<sort> should no longer lead to bus errors
2420 Numerous bugfixes catch small issues caused by the recently-added Lexer API.
2424 Smart match against C<@_> sometimes gave false negatives. [perl #71078]
2428 C<$@> may now be assigned a read-only value (without error or busting
2433 C<sort> called recursively from within an active comparison subroutine no
2434 longer causes a bus error if run multiple times. [perl #71076]
2438 Tie::Hash::NamedCapture::* will not abort if passed bad input (RT #71828)
2442 @_ and $_ no longer leak under threads (RT #34342 and #41138, also
2447 C<-I> on shebang line now adds directories in front of @INC
2448 as documented, and as does C<-I> when specified on the command-line.
2452 C<kill> is now fatal when called on non-numeric process identifiers.
2453 Previously, an C<undef> process identifier would be interpreted as a
2454 request to kill process 0, which would terminate the current process
2455 group on POSIX systems. Since process identifiers are always integers,
2456 killing a non-numeric process is now fatal.
2460 5.10.0 inadvertently disabled an optimisation, which caused a measurable
2461 performance drop in list assignment, such as is often used to assign
2462 function parameters from C<@_>. The optimisation has been re-instated, and
2463 the performance regression fixed. (This fix is also present in 5.10.1)
2467 Fixed memory leak on C<while (1) { map 1, 1 }> [RT #53038].
2471 Some potential coredumps in PerlIO fixed [RT #57322,54828].
2475 The debugger now works with lvalue subroutines.
2479 The debugger's C<m> command was broken on modules that defined constants
2484 C<crypt> and string complement could return tainted values for untainted
2485 arguments [RT #59998].
2489 The C<-i>I<.suffix> command-line switch now recreates the file using
2490 restricted permissions, before changing its mode to match the original
2491 file. This eliminates a potential race condition [RT #60904].
2495 On some Unix systems, the value in C<$?> would not have the top bit set
2496 (C<$? & 128>) even if the child core dumped.
2500 Under some circumstances, C<$^R> could incorrectly become undefined
2505 In the XS API, various hash functions, when passed a pre-computed hash where
2506 the key is UTF-8, might result in an incorrect lookup.
2510 XS code including F<XSUB.h> before F<perl.h> gave a compile-time error
2515 C<< $object-E<gt>isa('Foo') >> would report false if the package C<Foo>
2516 didn't exist, even if the object's C<@ISA> contained C<Foo>.
2520 Various bugs in the new-to 5.10.0 mro code, triggered by manipulating
2521 C<@ISA>, have been found and fixed.
2525 Bitwise operations on references could crash the interpreter, e.g.
2526 C<$x=\$y; $x |= "foo"> [RT #54956].
2530 Patterns including alternation might be sensitive to the internal UTF-8
2531 representation, e.g.
2533 my $byte = chr(192);
2534 my $utf8 = chr(192); utf8::upgrade($utf8);
2535 $utf8 =~ /$byte|X}/i; # failed in 5.10.0
2539 Within UTF8-encoded Perl source files (i.e. where C<use utf8> is in
2540 effect), double-quoted literal strings could be corrupted where a C<\xNN>,
2541 C<\0NNN> or C<\N{}> is followed by a literal character with ordinal value
2542 greater than 255 [RT #59908].
2546 C<B::Deparse> failed to correctly deparse various constructs:
2547 C<readpipe STRING> [RT #62428], C<CORE::require(STRING)> [RT #62488],
2548 C<sub foo(_)> [RT #62484].
2552 Using C<setpgrp> with no arguments could corrupt the perl stack.
2556 The block form of C<eval> is now specifically trappable by C<Safe> and
2557 C<ops>. Previously it was erroneously treated like string C<eval>.
2561 In 5.10.0, the two characters C<[~> were sometimes parsed as the smart
2562 match operator (C<~~>) [RT #63854].
2566 In 5.10.0, the C<*> quantifier in patterns was sometimes treated as
2567 C<{0,32767}> [RT #60034, #60464]. For example, this match would fail:
2569 ("ab" x 32768) =~ /^(ab)*$/
2573 C<shmget> was limited to a 32 bit segment size on a 64 bit OS [RT #63924].
2577 Using C<next> or C<last> to exit a C<given> block no longer produces a
2578 spurious warning like the following:
2580 Exiting given via last at foo.pl line 123
2584 Assigning a format to a glob could corrupt the format; e.g.:
2586 *bar=*foo{FORMAT}; # foo format now bad
2590 Attempting to coerce a typeglob to a string or number could cause an
2591 assertion failure. The correct error message is now generated,
2592 C<Can't coerce GLOB to I<$type>>.
2596 Under C<use filetest 'access'>, C<-x> was using the wrong access
2597 mode. This has been fixed [RT #49003].
2601 C<length> on a tied scalar that returned a Unicode value would not be
2602 correct the first time. This has been fixed.
2606 Using an array C<tie> inside in array C<tie> could SEGV. This has been
2611 A race condition inside C<PerlIOStdio_close()> has been identified and
2612 fixed. This used to cause various threading issues, including SEGVs.
2616 In C<unpack>, the use of C<()> groups in scalar context was internally
2617 placing a list on the interpreter's stack, which manifested in various
2618 ways, including SEGVs. This is now fixed [RT #50256].
2622 Magic was called twice in C<substr>, C<\&$x>, C<tie $x, $m> and C<chop>.
2623 These have all been fixed.
2627 A 5.10.0 optimisation to clear the temporary stack within the implicit
2628 loop of C<s///ge> has been reverted, as it turned out to be the cause of
2629 obscure bugs in seemingly unrelated parts of the interpreter [commit
2634 The line numbers for warnings inside C<elsif> are now correct.
2638 The C<..> operator now works correctly with ranges whose ends are at or
2639 close to the values of the smallest and largest integers.
2643 C<binmode STDIN, ':raw'> could lead to segmentation faults on some platforms.
2644 This has been fixed [RT #54828].
2648 An off-by-one error meant that C<index $str, ...> was effectively being
2649 executed as C<index "$str\0", ...>. This has been fixed [RT #53746].
2653 Various leaks associated with named captures in regexes have been fixed
2658 A weak reference to a hash would leak. This was affecting C<DBI>
2663 Using (?|) in a regex could cause a segfault [RT #59734].
2667 Use of a UTF-8 C<tr//> within a closure could cause a segfault [RT #61520].
2671 Calling C<Perl_sv_chop()> or otherwise upgrading an SV could result in an
2672 unaligned 64-bit access on the SPARC architecture [RT #60574].
2676 In the 5.10.0 release, C<inc_version_list> would incorrectly list
2677 C<5.10.*> after C<5.8.*>; this affected the C<@INC> search order
2682 In 5.10.0, C<pack "a*", $tainted_value> returned a non-tainted value
2687 In 5.10.0, C<printf> and C<sprintf> could produce the fatal error
2688 C<panic: utf8_mg_pos_cache_update> when printing UTF-8 strings
2693 In the 5.10.0 release, a dynamically created C<AUTOLOAD> method might be
2694 missed (method cache issue) [RT #60220,60232].
2698 In the 5.10.0 release, a combination of C<use feature> and C<//ee> could
2699 cause a memory leak [RT #63110].
2703 C<-C> on the shebang (C<#!>) line is once more permitted if it is also
2704 specified on the command line. C<-C> on the shebang line used to be a
2705 silent no-op I<if> it was not also on the command line, so perl 5.10.0
2706 disallowed it, which broke some scripts. Now perl checks whether it is
2707 also on the command line and only dies if it is not [RT #67880].
2711 In 5.10.0, certain types of re-entrant regular expression could crash,
2712 or cause the following assertion failure [RT #60508]:
2714 Assertion rx->sublen >= (s - rx->subbeg) + i failed
2718 Perl now includes previously missing files from the Unicode Character
2723 Perl now honors C<TMPDIR> when opening an anonymous temporary file.
2728 =head1 Platform Specific Changes
2730 Perl is incredibly portable. In general, if a platform has a C compiler,
2731 someone has ported Perl to it (or will soon). We're happy to announce
2732 that Perl 5.12 includes support for several new platforms. At the same
2733 time, it's time to bid farewell to some (very) old friends.
2735 =head2 New Platforms
2741 Perl's developers have merged patches from Haiku's maintainers. Perl
2742 should now build on Haiku.
2746 Perl should now build on MirOS BSD.
2750 =head2 Discontinued Platforms
2762 =head2 Updated Platforms
2772 Removed F<libbsd> for AIX 5L and 6.1. Only C<flock()> was used from
2777 Removed F<libgdbm> for AIX 5L and 6.1 if F<libgdbm> < 1.8.3-5 is
2778 installed. The F<libgdbm> is delivered as an optional package with the
2779 AIX Toolbox. Unfortunately the versions below 1.8.3-5 are broken.
2783 Hints changes mean that AIX 4.2 should work again.
2793 Perl now supports IPv6 on Cygwin 1.7 and newer.
2797 On Cygwin we now strip the last number from the DLL. This has been the
2798 behaviour in the cygwin.com build for years. The hints files have been
2803 =item Darwin (Mac OS X)
2809 Skip testing the be_BY.CP1131 locale on Darwin 10 (Mac OS X 10.6),
2810 as it's still buggy.
2814 Correct infelicities in the regexp used to identify buggy locales
2815 on Darwin 8 and 9 (Mac OS X 10.4 and 10.5, respectively).
2825 Fix thread library selection [perl #69686]
2835 The hints files now identify the correct threading libraries on FreeBSD 7
2846 We now work around a bizarre preprocessor bug in the Irix 6.5 compiler:
2847 C<cc -E -> unfortunately goes into K&R mode, but C<cc -E file.c> doesn't.
2857 Hints now supports versions 5.*.
2867 C<-UDEBUGGING> is now the default on VMS.
2869 Like it has been everywhere else for ages and ages. Also make command-line
2870 selection of -UDEBUGGING and -DDEBUGGING work in configure.com; before
2871 the only way to turn it off was by saying no in answer to the interactive
2876 The default pipe buffer size on VMS has been updated to 8192 on 64-bit
2881 Reads from the in-memory temporary files of C<PerlIO::scalar> used to fail
2882 if C<$/> was set to a numeric reference (to indicate record-style reads).
2887 VMS now supports C<getgrgid>.
2891 Many improvements and cleanups have been made to the VMS file name handling
2892 and conversion code.
2896 Enabling the C<PERL_VMS_POSIX_EXIT> logical name now encodes a POSIX exit
2897 status in a VMS condition value for better interaction with GNV's bash
2898 shell and other utilities that depend on POSIX exit values. See
2899 L<perlvms/"$?"> for details.
2903 C<File::Copy> now detects Unix compatibility mode on VMS.
2913 Various changes from Stratus have been merged in.
2923 There is now support for Symbian S60 3.2 SDK and S60 5.0 SDK.
2933 Perl 5.12 supports Windows 2000 and later. The supporting code for
2934 legacy versions of Windows is still included, but will be removed
2935 during the next development cycle.
2939 Initial support for building Perl with MinGW-w64 is now available.
2943 F<perl.exe> now includes a manifest resource to specify the C<trustInfo>
2944 settings for Windows Vista and later. Without this setting Windows
2945 would treat F<perl.exe> as a legacy application and apply various
2946 heuristics like redirecting access to protected file system areas
2947 (like the "Program Files" folder) to the users "VirtualStore"
2948 instead of generating a proper "permission denied" error.
2950 The manifest resource also requests the Microsoft Common-Controls
2951 version 6.0 (themed controls introduced in Windows XP). Check out the
2952 Win32::VisualStyles module on CPAN to switch back to old style
2953 unthemed controls for legacy applications.
2957 The C<-t> filetest operator now only returns true if the filehandle
2958 is connected to a console window. In previous versions of Perl it
2959 would return true for all character mode devices, including F<NUL>
2964 The C<-p> filetest operator now works correctly, and the
2965 Fcntl::S_IFIFO constant is defined when Perl is compiled with
2966 Microsoft Visual C. In previous Perl versions C<-p> always
2967 returned a false value, and the Fcntl::S_IFIFO constant
2970 This bug is specific to Microsoft Visual C and never affected
2971 Perl binaries built with MinGW.
2975 The socket error codes are now more widely supported: The POSIX
2976 module will define the symbolic names, like POSIX::EWOULDBLOCK,
2977 and stringification of socket error codes in $! works as well
2980 C:\>perl -MPOSIX -E "$!=POSIX::EWOULDBLOCK; say $!"
2981 A non-blocking socket operation could not be completed immediately.
2985 flock() will now set sensible error codes in $!. Previous Perl versions
2986 copied the value of $^E into $!, which caused much confusion.
2990 select() now supports all empty C<fd_set>s more correctly.
2994 C<'.\foo'> and C<'..\foo'> were treated differently than
2995 C<'./foo'> and C<'../foo'> by C<do> and C<require> [RT #63492].
2999 Improved message window handling means that C<alarm> and C<kill> messages
3000 will no longer be dropped under race conditions.
3004 Various bits of Perl's build infrastructure are no longer converted to
3005 win32 line endings at release time. If this hurts you, please report the
3006 problem with the L<perlbug> program included with perl.
3013 =head1 Known Problems
3015 This is a list of some significant unfixed bugs, which are regressions
3016 from either 5.10.x or 5.8.x.
3022 C<List::Util::first> misbehaves in the presence of a lexical C<$_>
3023 (typically introduced by C<my $_> or implicitly by C<given>). The variable
3024 which gets set for each iteration is the package variable C<$_>, not the
3025 lexical C<$_> [RT #67694].
3027 A similar issue may occur in other modules that provide functions which
3028 take a block as their first argument, like
3030 foo { ... $_ ...} list
3034 Some regexes may run much more slowly when run in a child thread compared
3035 with the thread the pattern was compiled into [RT #55600].
3039 Things like C<"\N{LATIN SMALL LIGATURE FF}" =~ /\N{LATIN SMALL LETTER F}+/>
3040 will appear to hang as they get into a very long running loop [RT #72998].
3044 Several porters have reported mysterious crashes when Perl's entire
3045 test suite is run after a build on certain Windows 2000 systems. When
3046 run by hand, the individual tests reportedly work fine.
3056 This one is actually a change introduced in 5.10.0, but it was missed
3057 from that release's perldelta, so it is mentioned here instead.
3059 A bugfix related to the handling of the C</m> modifier and C<qr> resulted
3060 in a change of behaviour between 5.8.x and 5.10.0:
3062 # matches in 5.8.x, doesn't match in 5.10.0
3063 $re = qr/^bar/; "foo\nbar" =~ /$re/m;
3067 =head1 Acknowledgements
3069 Perl 5.12.0 represents approximately two years of development since
3070 Perl 5.10.0 and contains over 750,000 lines of changes across over
3071 3,000 files from over 200 authors and committers.
3073 Perl continues to flourish into its third decade thanks to a vibrant
3074 community of users and developers. The following people are known to
3075 have contributed the improvements that became Perl 5.12.0:
3077 Aaron Crane, Abe Timmerman, Abhijit Menon-Sen, Abigail, Adam Russell,
3078 Adriano Ferreira, Ævar Arnfjörð Bjarmason, Alan Grover, Alexandr
3079 Ciornii, Alex Davies, Alex Vandiver, Andreas Koenig, Andrew Rodland,
3080 andrew@sundale.net, Andy Armstrong, Andy Dougherty, Jose AUGUSTE-ETIENNE,
3081 Benjamin Smith, Ben Morrow, bharanee rathna, Bo Borgerson, Bo Lindbergh,
3082 Brad Gilbert, Bram, Brendan O'Dea, brian d foy, Charles Bailey,
3083 Chip Salzenberg, Chris 'BinGOs' Williams, Christoph Lamprecht, Chris
3084 Williams, chromatic, Claes Jakobsson, Craig A. Berry, Dan Dascalescu,
3085 Daniel Frederick Crisman, Daniel M. Quinlan, Dan Jacobson, Dan Kogai,
3086 Dave Mitchell, Dave Rolsky, David Cantrell, David Dick, David Golden,
3087 David Mitchell, David M. Syzdek, David Nicol, David Wheeler, Dennis
3088 Kaarsemaker, Dintelmann, Peter, Dominic Dunlop, Dr.Ruud, Duke Leto,
3089 Enrico Sorcinelli, Eric Brine, Father Chrysostomos, Florian Ragwitz,
3090 Frank Wiegand, Gabor Szabo, Gene Sullivan, Geoffrey T. Dairiki, George
3091 Greer, Gerard Goossen, Gisle Aas, Goro Fuji, Graham Barr, Green, Paul,
3092 Hans Dieter Pearcey, Harmen, H. Merijn Brand, Hugo van der Sanden,
3093 Ian Goodacre, Igor Sutton, Ingo Weinhold, James Bence, James Mastros,
3094 Jan Dubois, Jari Aalto, Jarkko Hietaniemi, Jay Hannah, Jerry Hedden,
3095 Jesse Vincent, Jim Cromie, Jody Belka, John E. Malmberg, John Malmberg,
3096 John Peacock, John Peacock via RT, John P. Linderman, John Wright,
3097 Josh ben Jore, Jos I. Boumans, Karl Williamson, Kenichi Ishigaki, Ken
3098 Williams, Kevin Brintnall, Kevin Ryde, Kurt Starsinic, Leon Brocard,
3099 Lubomir Rintel, Luke Ross, Marcel Grünauer, Marcus Holland-Moritz, Mark
3100 Jason Dominus, Marko Asplund, Martin Hasch, Mashrab Kuvatov, Matt Kraai,
3101 Matt S Trout, Max Maischein, Michael Breen, Michael Cartmell, Michael
3102 G Schwern, Michael Witten, Mike Giroux, Milosz Tanski, Moritz Lenz,
3103 Nicholas Clark, Nick Cleaton, Niko Tyni, Offer Kaye, Osvaldo Villalon,
3104 Paul Fenwick, Paul Gaborit, Paul Green, Paul Johnson, Paul Marquess,
3105 Philip Hazel, Philippe Bruhat, Rafael Garcia-Suarez, Rainer Tammer,
3106 Rajesh Mandalemula, Reini Urban, Renée Bäcker, Ricardo Signes,
3107 Ricardo SIGNES, Richard Foley, Rich Rauenzahn, Rick Delaney, Risto
3108 Kankkunen, Robert May, Roberto C. Sanchez, Robin Barker, SADAHIRO
3109 Tomoyuki, Salvador Ortiz Garcia, Sam Vilain, Scott Lanning, Sébastien
3110 Aperghis-Tramoni, Sérgio Durigan Júnior, Shlomi Fish, Simon 'corecode'
3111 Schubert, Sisyphus, Slaven Rezic, Smylers, Steffen Müller, Steffen
3112 Ullrich, Stepan Kasal, Steve Hay, Steven Schubiger, Steve Peters, Tels,
3113 The Doctor, Tim Bunce, Tim Jenness, Todd Rinaldo, Tom Christiansen,
3114 Tom Hukins, Tom Wyant, Tony Cook, Torsten Schoenfeld, Tye McQueen,
3115 Vadim Konovalov, Vincent Pit, Hio YAMASHINA, Yasuhiro Matsumoto,
3116 Yitzchak Scott-Thoennes, Yuval Kogman, Yves Orton, Zefram, Zsban Ambrus
3118 This is woefully incomplete as it's automatically generated from version
3119 control history. In particular, it doesn't include the names of the
3120 (very much appreciated) contributors who reported issues in previous
3121 versions of Perl that helped make Perl 5.12.0 better. For a more complete
3122 list of all of Perl's historical contributors, please see the C<AUTHORS>
3123 file in the Perl 5.12.0 distribution.
3125 Our "retired" pumpkings Nicholas Clark and Rafael Garcia-Suarez
3126 deserve special thanks for their brilliant and substantive ongoing
3127 contributions. Nicholas personally authored over 30% of the patches
3128 since 5.10.0. Rafael comes in second in patch authorship with 11%,
3129 but is first by a long shot in committing patches authored by others,
3130 pushing 44% of the commits since 5.10.0 in this category, often after
3131 providing considerable coaching to the patch authors. These statistics
3132 in no way comprise all of their contributions, but express in shorthand
3133 that we couldn't have done it without them.
3135 Many of the changes included in this version originated in the CPAN
3136 modules included in Perl's core. We're grateful to the entire CPAN
3137 community for helping Perl to flourish.
3139 =head1 Reporting Bugs
3141 If you find what you think is a bug, you might check the articles
3142 recently posted to the comp.lang.perl.misc newsgroup and the perl
3143 bug database at L<http://rt.perl.org/perlbug/>. There may also be
3144 information at L<http://www.perl.org/>, the Perl Home Page.
3146 If you believe you have an unreported bug, please run the B<perlbug>
3147 program included with your release. Be sure to trim your bug down
3148 to a tiny but sufficient test case. Your bug report, along with the
3149 output of C<perl -V>, will be sent off to perlbug@perl.org to be
3150 analyzed by the Perl porting team.
3152 If the bug you are reporting has security implications, which make it
3153 inappropriate to send to a publicly archived mailing list, then please send
3154 it to perl5-security-report@perl.org. This points to a closed subscription
3155 unarchived mailing list, which includes all the core committers, who be able
3156 to help assess the impact of issues, figure out a resolution, and help
3157 co-ordinate the release of patches to mitigate or fix the problem across all
3158 platforms on which Perl is supported. Please only use this address for
3159 security issues in the Perl core, not for modules independently
3160 distributed on CPAN.
3164 The F<Changes> file for an explanation of how to view exhaustive details
3167 The F<INSTALL> file for how to build Perl.
3169 The F<README> file for general stuff.
3171 The F<Artistic> and F<Copying> files for copyright information.