5 perl5110delta - what is new for perl v5.11.0
9 This document describes differences between the 5.10.0 release and
10 the 5.11.0 development release.
12 =head1 Incompatible Changes
14 =head2 Unicode interpretation of \w, \d, \s, and the POSIX character classes redefined.
16 Previous versions of Perl tried to map POSIX style character class definitions onto
17 Unicode property names so that patterns would "dwim" when matches were made against latin-1 or
18 unicode strings. This proved to be a mistake, breaking character class negation, causing
19 forward compatibility problems (as Unicode keeps updating their property definitions and adding
20 new characters), and other problems.
22 Therefore we have now defined a new set of artificial "unicode" property names which will be
23 used to do unicode matching of patterns using POSIX style character classes and perl short-form
24 escape character classes like \w and \d.
26 The key change here is that \d will no longer match every digit in the unicode standard
27 (there are thousands) nor will \w match every word character in the standard, instead they
28 will match precisely their POSIX or Perl definition.
30 Those needing to match based on Unicode properties can continue to do so by using the \p{} syntax
31 to match whichever property they like, including the new artificial definitions.
33 B<NOTE:> This is a backwards incompatible no-warning change in behaviour. If you are upgrading
34 and you process large volumes of text look for POSIX and Perl style character classes and
35 change them to the relevent property name (by removing the word 'Posix' from the current name).
37 The following table maps the POSIX character class names, the escapes and the old and new
38 Unicode property mappings:
40 POSIX Esc Class New-Property ! Old-Property
41 ----------------------------------------------+-------------
42 alnum [0-9A-Za-z] IsPosixAlnum ! IsAlnum
43 alpha [A-Za-z] IsPosixAlpha ! IsAlpha
44 ascii [\000-\177] IsASCII = IsASCII
45 blank [\011 ] IsPosixBlank !
46 cntrl [\0-\37\177] IsPosixCntrl ! IsCntrl
47 digit \d [0-9] IsPosixDigit ! IsDigit
48 graph [!-~] IsPosixGraph ! IsGraph
49 lower [a-z] IsPosixLower ! IsLower
50 print [ -~] IsPosixPrint ! IsPrint
51 punct [!-/:-@[-`{-~] IsPosixPunct ! IsPunct
52 space [\11-\15 ] IsPosixSpace ! IsSpace
53 \s [\11\12\14\15 ] IsPerlSpace ! IsSpacePerl
54 upper [A-Z] IsPosixUpper ! IsUpper
55 word \w [0-9A-Z_a-z] IsPerlWord ! IsWord
56 xdigit [0-9A-Fa-f] IsXDigit = IsXDigit
58 If you wish to build perl with the old mapping you may do so by setting
60 #define PERL_LEGACY_UNICODE_CHARCLASS_MAPPINGS 1
62 in regcomp.h, and then setting
64 PERL_TEST_LEGACY_POSIX_CC
66 to true your enviornment when testing.
69 =head2 @INC reorganization
71 In @INC, ARCHLIB and PRIVLIB now occur after after the current version's
72 site_perl and vendor_perl.
74 =head2 Switch statement changes
76 The handling of complex expressions by the C<given>/C<when> switch
77 statement has been enhanced. These enhancements are also available in
78 5.10.1 and subsequent 5.10 releases. There are two new cases where C<when> now
79 interprets its argument as a boolean, instead of an expression to be used
84 =item flip-flop operators
86 The C<..> and C<...> flip-flop operators are now evaluated in boolean
87 context, following their usual semantics; see L<perlop/"Range Operators">.
89 Note that, as in perl 5.10.0, C<when (1..10)> will not work to test
90 whether a given value is an integer between 1 and 10; you should use
91 C<when ([1..10])> instead (note the array reference).
93 However, contrary to 5.10.0, evaluating the flip-flop operators in boolean
94 context ensures it can now be useful in a C<when()>, notably for
95 implementing bistable conditions, like in:
97 when (/^=begin/ .. /^=end/) {
101 =item defined-or operator
103 A compound expression involving the defined-or operator, as in
104 C<when (expr1 // expr2)>, will be treated as boolean if the first
105 expression is boolean. (This just extends the existing rule that applies
106 to the regular or operator, as in C<when (expr1 || expr2)>.)
110 The next section details more changes brought to the semantics to
111 the smart match operator, that naturally also modify the behaviour
112 of the switch statements where smart matching is implicitly used.
113 These changers were also made for the 5.10.1 release, and will remain in
114 subsequent 5.10 releases.
116 =head2 Smart match changes
118 =head3 Changes to type-based dispatch
120 The smart match operator C<~~> is no longer commutative. The behaviour of
121 a smart match now depends primarily on the type of its right hand
122 argument. Moreover, its semantics have been adjusted for greater
123 consistency or usefulness in several cases. While the general backwards
124 compatibility is maintained, several changes must be noted:
130 Code references with an empty prototype are no longer treated specially.
131 They are passed an argument like the other code references (even if they
132 choose to ignore it).
136 C<%hash ~~ sub {}> and C<@array ~~ sub {}> now test that the subroutine
137 returns a true value for each key of the hash (or element of the
138 array), instead of passing the whole hash or array as a reference to
143 Due to the commutativity breakage, code references are no longer
144 treated specially when appearing on the left of the C<~~> operator,
145 but like any vulgar scalar.
149 C<undef ~~ %hash> is always false (since C<undef> can't be a key in a
150 hash). No implicit conversion to C<""> is done (as was the case in perl
155 C<$scalar ~~ @array> now always distributes the smart match across the
156 elements of the array. It's true if one element in @array verifies
157 C<$scalar ~~ $element>. This is a generalization of the old behaviour
158 that tested whether the array contained the scalar.
162 The full dispatch table for the smart match operator is given in
163 L<perlsyn/"Smart matching in detail">.
165 =head3 Smart match and overloading
167 According to the rule of dispatch based on the rightmost argument type,
168 when an object overloading C<~~> appears on the right side of the
169 operator, the overload routine will always be called (with a 3rd argument
170 set to a true value, see L<overload>.) However, when the object will
171 appear on the left, the overload routine will be called only when the
172 rightmost argument is a simple scalar. This way distributivity of smart match
173 across arrays is not broken, as well as the other behaviours with complex
174 types (coderefs, hashes, regexes). Thus, writers of overloading routines
175 for smart match mostly need to worry only with comparing against a scalar,
176 and possibly with stringification overloading; the other common cases
177 will be automatically handled consistently.
179 C<~~> will now refuse to work on objects that do not overload it (in order
180 to avoid relying on the object's underlying structure). (However, if the
181 object overloads the stringification or the numification operators, and
182 if overload fallback is active, it will be used instead, as usual.)
184 =head2 Labels can't be keywords
186 Labels used as targets for the C<goto>, C<last>, C<next> or C<redo>
187 statements cannot be keywords anymore. This restriction will prevent
188 potential confusion between the C<goto LABEL> and C<goto EXPR> syntaxes:
189 for example, a statement like C<goto print> would jump to a label whose
190 name would be the return value of C<print()>, (usually 1), instead of a
191 label named C<print>. Moreover, the other control flow statements
192 would just ignore any keyword passed to them as a label name. Since
193 such labels cannot be defined anymore, this kind of error will be
196 =head2 Other incompatible changes
202 The semantics of C<use feature :5.10*> have changed slightly.
203 See L<"Modules and Pragmata"> for more information.
207 It is now a run-time error to use the smart match operator C<~~>
208 with an object that has no overload defined for it. (This way
209 C<~~> will not break encapsulation by matching against the
210 object's internal representation as a reference.)
214 The version control system used for the development of the perl
215 interpreter has been switched from Perforce to git. This is mainly an
216 internal issue that only affects people actively working on the perl core;
217 but it may have minor external visibility, for example in some of details
218 of the output of C<perl -V>. See L<perlrepository> for more information.
222 The internal structure of the C<ext/> directory in the perl source has
223 been reorganised. In general, a module C<Foo::Bar> whose source was
224 stored under F<ext/Foo/Bar/> is now located under F<ext/Foo-Bar/>. Also,
225 nearly all dual-life modules have been moved from F<lib/> to F<ext/>. This
226 is purely a source tarball change, and should make no difference to the
227 compilation or installation of perl, unless you have a very customised build
228 process that explicitly relies on this structure, or which hard-codes the
229 C<nonxs_ext> F<Configure> parameter. Specifically, this change does not by
230 default alter the location of any files in the final installation.
234 As part of the C<Test::Harness> 2.x to 3.x upgrade, the experimental
235 C<Test::Harness::Straps> module has been removed.
236 See L</"Updated Modules"> for more details.
240 As part of the C<ExtUtils::MakeMaker> upgrade, the
241 C<ExtUtils::MakeMaker::bytes> and C<ExtUtils::MakeMaker::vmsish> modules
242 have been removed from this distribution.
246 C<Module::CoreList> no longer contains the C<%:patchlevel> hash.
250 This one is actually a change introduced in 5.10.0, but it was missed
251 from that release's perldelta, so it is mentioned here instead.
253 A bugfix related to the handling of the C</m> modifier and C<qr> resulted
254 in a change of behaviour between 5.8.x and 5.10.0:
256 # matches in 5.8.x, doesn't match in 5.10.0
257 $re = qr/^bar/; "foo\nbar" =~ /$re/m;
261 C<length undef> now returns undef.
265 Unsupported private C API functions are now declared "static" to prevent
266 leakage to Perl's public API.
270 To support the bootstrapping process, F<miniperl> no longer builds with
271 UTF-8 support in the regexp engine.
273 This allows a build to complete with PERL_UNICODE set and a UTF-8 locale.
274 Without this there's a bootstrapping problem, as miniperl can't load the UTF-8
275 components of the regexp engine, because they're not yet built.
279 F<miniperl>'s @INC is now restricted to just -I..., the split of $ENV{PERL5LIB}, and "."
283 A space or a newline is now required after a C<"#line XXX"> directive.
287 Tied filehandles now have an additional method EOF which provides the EOF type
291 To better match all other flow control statements, C<foreach> may no longer be used as an attribute.
295 =head1 Core Enhancements
297 =head2 Unicode Character Database 5.1.0
299 The copy of the Unicode Character Database included in Perl 5.11.0 has
300 been updated to 5.1.0 from 5.0.0. See
301 L<http://www.unicode.org/versions/Unicode5.1.0/#Notable_Changes> for the
304 =head2 A proper interface for pluggable Method Resolution Orders
306 As of Perl 5.11.0 there is a new interface for plugging and using method
307 resolution orders other than the default (linear depth first search).
308 The C3 method resolution order added in 5.10.0 has been re-implemented as
309 a plugin, without changing its Perl-space interface. See L<perlmroapi> for
312 =head2 The C<overloading> pragma
314 This pragma allows you to lexically disable or enable overloading
315 for some or all operations. (Yuval Kogman)
317 =head2 C<\N> regex escape
319 A new regex escape has been added, C<\N>. It will match any character that
320 is not a newline, independently from the presence or absence of the single
321 line match modifier C</s>. (If C<\N> is followed by an opening brace and
322 by a letter, perl will still assume that a Unicode character name is
323 coming, so compatibility is preserved.) (Rafael Garcia-Suarez)
325 =head2 Implicit strictures
327 Using the C<use VERSION> syntax with a version number greater or equal
328 to 5.11.0 will also lexically enable strictures just like C<use strict>
329 would do (in addition to enabling features.) So, the following:
338 =head2 Parallel tests
340 The core distribution can now run its regression tests in parallel on
341 Unix-like platforms. Instead of running C<make test>, set C<TEST_JOBS> in
342 your environment to the number of tests to run in parallel, and run
343 C<make test_harness>. On a Bourne-like shell, this can be done as
345 TEST_JOBS=3 make test_harness # Run 3 tests in parallel
347 An environment variable is used, rather than parallel make itself, because
348 L<TAP::Harness> needs to be able to schedule individual non-conflicting test
349 scripts itself, and there is no standard interface to C<make> utilities to
350 interact with their job schedulers.
352 Note that currently some test scripts may fail when run in parallel (most
353 notably C<ext/IO/t/io_dir.t>). If necessary run just the failing scripts
354 again sequentially and see if the failures go away.
356 =head2 The C<...> operator
358 A new operator, C<...>, nicknamed the Yada Yada operator, has been added.
359 It is intended to mark placeholder code, that is not yet implemented.
360 See L<perlop/"Yada Yada Operator">. (chromatic)
362 =head2 DTrace support
364 Some support for DTrace has been added. See "DTrace support" in F<INSTALL>.
366 =head2 Support for C<configure_requires> in CPAN module metadata
368 Both C<CPAN> and C<CPANPLUS> now support the C<configure_requires> keyword
369 in the F<META.yml> metadata file included in most recent CPAN distributions.
370 This allows distribution authors to specify configuration prerequisites that
371 must be installed before running F<Makefile.PL> or F<Build.PL>.
373 See the documentation for C<ExtUtils::MakeMaker> or C<Module::Build> for more
374 on how to specify C<configure_requires> when creating a distribution for CPAN.
376 =head2 C<each> is now more flexible
378 The C<each> function can now operate on arrays.
380 =head2 Y2038 compliance
382 Perl's core time-related functions are now Y2038 compliant. (With 29
385 =head2 C<$,> flexibilty
387 The variable C<$,> may now be tied.
389 =head2 // in where clauses
391 // now behaves like || in when clauses
393 =head2 Enabling warnings from your shell environment
395 You can now set C<-W> from the C<PERL5OPT> environment variable
397 =head2 C<delete local>
399 C<delete local> now allows you to lexically delete a hash entry.
401 =head2 New support for Abstract namespace sockets
403 Abstract namespace sockets are Linux-specific socket type that live in
404 AF_UNIX family, slightly abusing it to be able to use arbitrary
405 character arrays as addresses: They start with nul byte and are not
406 terminated by nul byte, but with the length passed to the socket()
409 =head1 Modules and Pragmata
411 =head2 Dual-lifed modules moved
413 Dual-lifed modules maintained primarily in the Perl core now live in dist/.
414 Dual-lifed modules maintained primarily on CPAN now live in cpan/
416 =head2 New Modules and Pragmata
422 This is a new lexically-scoped alternative for the C<Fatal> module.
423 The bundled version is 2.06_01. Note that in this release, using a string
424 eval when C<autodie> is in effect can cause the autodie behaviour to leak
425 into the surrounding scope. See L<autodie/"BUGS"> for more details.
427 =item C<Compress::Raw::Bzip2>
429 This has been added to the core (version 2.020).
433 This pragma establishes an ISA relationship with base classes at compile
434 time. It provides the key feature of C<base> without the feature creep.
436 =item C<Parse::CPAN::Meta>
438 This has been added to the core (version 1.39).
442 =head2 Pragmata Changes
448 See L</"The C<overloading> pragma"> above.
452 Upgraded from version 0.08 to 0.09.
456 The C<attrs> pragma has been removed. It had been marked as deprecated since
461 Upgraded from version 2.13 to 2.14. See L<parent> for a replacement.
465 Upgraded from version 0.22 to 0.23.
469 Upgraded from version 0.22 to 0.23.
473 Upgraded from version 0.22 to 0.23.
477 Upgraded from version 1.06 to 1.07.
479 The Unicode F<NameAliases.txt> database file has been added. This has the
480 effect of adding some extra C<\N> character names that formerly wouldn't
481 have been recognised; for example, C<"\N{LATIN CAPITAL LETTER GHA}">.
485 Upgraded from version 1.13 to 1.19. Some code has been shifted from run time to
486 compile time, and the amount of MRO cache flushing has been minimised.
490 The meaning of the C<:5.10> and C<:5.10.X> feature bundles has
491 changed slightly. The last component, if any (i.e. C<X>) is simply ignored.
492 This is predicated on the assumption that new features will not, in
493 general, be added to maintenance releases. So C<:5.10> and C<:5.10.X>
494 have identical effect. This is a change to the behaviour documented for
499 Upgraded from version 2.13 to 2.14 (this was just a version bump; there
500 were no functional changes).
504 Upgraded from version 0.5565 to 0.62.
508 Upgraded from version 1.06 to 1.07.
512 Upgraded from version 1.06 to 1.07.
516 See L</"The C<overloading> pragma"> above.
520 Upgraded from version 1.00 to 1.01. Performance for single inheritance is 40%
521 faster - see L</"Performance Enhancements"> below.
523 C<mro> is now implemented as an XS extension. The documented interface has not
524 changed. Code relying on the implementation detail that some C<mro::>
525 methods happened to be available at all times gets to "keep both pieces".
529 Upgraded from version 0.74 to 0.77.
533 =head2 Updated Modules
537 =item C<Archive::Extract>
539 Upgraded from version 0.24 to 0.34.
541 =item C<Archive::Tar>
543 Upgraded from version 1.38 to 1.52.
545 =item C<Attribute::Handlers>
547 Upgraded from version 0.79 to 0.85.
551 Upgraded from version 5.63 to 5.68.
555 Upgraded from version 1.05 to 1.06.
559 Upgraded from version 1.17 to 1.22.
563 Upgraded from version 1.05 to 1.11.
567 Upgraded from version 0.83 to 0.89.
571 Upgraded from version 1.09 to 1.11.
575 Upgraded from version 1.01 to 1.02.
579 Upgraded from version 1.10 to 1.11.
583 Upgraded from version 1.08 to 1.11.
585 L<Carp> now includes all the necessary code to function. Previously, it
586 used to be a lightweight placeholder that loaded the actual code from
587 C<Carp::Heavy> on demand. C<Carp::Heavy> is now a simple, empty module
588 kept for backwards compatibility for programs that used to pre-load it.
592 Upgraded from version 3.29 to 3.43.
593 (also includes the "default_value for popup_menu()" fix from 3.45).
595 =item C<Compress::Zlib>
597 Upgraded from version 2.008 to 2.020.
601 Upgraded from version 1.9205 to 1.9402. C<CPAN::FTP> has a local fix to
602 stop it being too verbose on download failure.
606 Upgraded from version 0.84 to 0.88.
608 =item C<CPANPLUS::Dist::Build>
610 Upgraded from version 0.06_02 to 0.36.
614 Upgraded from version 3.25_01 to 3.30.
616 =item C<Data::Dumper>
618 Upgraded from version 2.121_14 to 2.124.
622 Upgraded from version 1.01 to 1.02.
626 Upgraded from version 1.816_1 to 1.820.
628 =item C<Devel::PPPort>
630 Upgraded from version 3.13 to 3.19.
634 Upgraded from version 2.36_01 to 2.39.
638 Upgraded from version 5.45 to 5.47.
642 Upgraded from version 1.01 to 1.03.
646 Upgraded from version 1.12 to 1.13.
650 Upgraded from version 1.08 to 1.10.
654 Upgraded from version 2.23 to 2.35.
658 Upgraded from version 1.10 to 1.11.
662 Upgraded from version 5.62 to 5.63.
664 =item C<ExtUtils::CBuilder>
666 Upgraded from version 0.21 to 0.2602.
668 =item C<ExtUtils::Command>
670 Upgraded from version 1.13 to 1.16.
672 =item C<ExtUtils::Constant>
674 Upgraded from 0.20 to 0.22. (Note that neither of these versions are
677 =item C<ExtUtils::Embed>
679 Upgraded from version 1.27 to 1.28.
681 =item C<ExtUtils::Install>
683 Upgraded from version 1.44 to 1.54.
685 =item C<ExtUtils::MakeMaker>
687 Upgraded from version 6.42 to 6.55_02.
689 Note that C<ExtUtils::MakeMaker::bytes> and C<ExtUtils::MakeMaker::vmsish>
690 have been removed from this distribution.
692 =item C<ExtUtils::Manifest>
694 Upgraded from version 1.51_01 to 1.56.
696 =item C<ExtUtils::ParseXS>
698 Upgraded from version 2.18_02 to 2.2002.
702 Upgraded from version 1.05 to 2.06_01. See also the new pragma C<autodie>.
704 =item C<File::Basename>
706 Upgraded from version 2.76 to 2.77.
708 =item C<File::Compare>
710 Upgraded from version 1.1005 to 1.1006.
714 Upgraded from version 2.11 to 2.16.
716 File::Copy now always return 0 (not "") on failure.
718 FIXME - describe C<cp>
722 Upgraded from version 0.14 to 0.20.
726 Upgraded from version 1.12 to 1.14.
730 Upgraded from version 2.04 to 2.07_03.
734 Upgraded from version 3.2501 to 3.30.
738 Upgraded from version 1.00 to 1.01.
740 Added -X overloading, -M, -C and -A.
744 Upgraded from version 0.18 to 0.22.
748 Upgraded from version 1.07 to 1.08.
752 Upgraded from version 2.01 to 2.02.
754 =item C<Filter::Simple>
756 Upgraded from version 0.82 to 0.84.
758 =item C<Filter::Util::Call>
760 Upgraded from version 1.07 to 1.08.
764 Upgraded from version 1.49 to 1.50.
768 Upgraded from version 1.08 to 1.09.
770 =item C<Getopt::Long>
772 Upgraded from version 2.37 to 2.38.
774 =item C<Hash::Util::FieldHash>
776 Upgraded from version 1.03 to 1.04. This fixes a memory leak.
778 =item C<I18N::Collate>
780 Upgraded from version 1.00 to 1.01.
784 Upgraded from version 1.23_01 to 1.25.
786 This makes non-blocking mode work on Windows in C<IO::Socket::INET>
789 =item C<IO::Compress::*>
791 Upgraded from version 2.008 to 2.020.
795 Upgraded from version 1.06 to 1.07.
799 Upgraded from version 1.27 to 1.28.
803 Upgraded from version 1.30_01 to 1.31.
807 Upgraded from version 1.07 to 1.09.
811 Upgraded from version 0.40_1 to 0.46.
815 Upgraded from version 1.02 to 1.04.
819 Upgraded from version 1.05 to 2.01.
823 Upgraded from version 0.5565 to 0.62.
827 Upgraded from version 1.19 to 1.21.
829 =item C<Locale::MakeText>
831 Upgraded from version 1.12 to 1.13.
833 =item C<Log::Message>
835 Upgraded from version 0.01 to 0.02.
837 =item C<Math::BigFloat>
839 Upgraded from version 1.59 to 1.60.
841 =item C<Math::BigInt>
843 Upgraded from version 1.88 to 1.89.
845 =item C<Math::BigInt::FastCalc>
847 Upgraded from version 0.16 to 0.19.
849 =item C<Math::BigRat>
851 Upgraded from version 0.21 to 0.22.
853 =item C<Math::Complex>
855 Upgraded from version 1.37 to 1.56.
859 Upgraded from version 1.04 to 1.20.
863 Upgraded from version 1.01_02 to 1.01_03 (just a minor documentation
866 =item C<Module::Build>
868 Upgraded from version 0.2808_01 to 0.34_02.
870 =item C<Module::CoreList>
872 Upgraded from version 2.13 to 2.18. This release no longer contains the
873 C<%Module::CoreList::patchlevel> hash.
875 =item C<Module::Load>
877 Upgraded from version 0.12 to 0.16.
879 =item C<Module::Load::Conditional>
881 Upgraded from version 0.22 to 0.30.
883 =item C<Module::Loaded>
885 Upgraded from version 0.01 to 0.02.
887 =item C<Module::Pluggable>
889 Upgraded from version 3.6 to 3.9.
893 Upgraded from version 1.07 to 1.08.
897 Upgraded from version 2.33 to 2.36.
901 Upgraded from version 0.60_01 to 0.64.
903 =item C<Object::Accessor>
905 Upgraded from version 0.32 to 0.34.
909 Upgraded from version 1.03 to 1.04.
911 =item C<Package::Constants>
913 Upgraded from version 0.01 to 0.02.
917 Upgraded from version 1.04 to 1.06.
921 Upgraded from version 0.04 to 0.07.
925 Upgraded from version 2.16 to 2.22.
929 Upgraded from version 1.35 to 1.37.
931 =item C<Pod::Plainer>
933 Upgraded from version 0.01 to 1.01.
935 There are no code changes - the version bump is because C<Pod::Plainer> has
936 been released to CPAN as a stand-alone distribution, and will be removed from
937 the core distribution in 5.14.
941 Upgrade from version 3.14_02 to 3.15.
945 Upgraded from version 3.05 to 3.07.
949 Upgraded from version 3.08 to 3.13.
953 Upgraded from version 1.13 to 1.17.
957 Upgraded from 2.12 to 2.18.
959 =item C<Scalar::Util>
961 Upgraded from version 1.19 to 1.21.
965 Upgraded from 1.01 to 1.02.
969 Upgraded from 1.11 to 1.17.
973 Upgraded from 1.80 to 1.84.
975 As of 1.84, C<Socket> can now handle abstract namespace sockets on Linux.
980 Upgraded from 2.18 to 2.20.
984 Upgraded from version 2.13 to 2.14. Please see L</Deprecations>.
988 Upgraded from version 1.06 to 1.07.
992 Upgraded from version 0.22 to 0.27.
994 =item C<Term::ANSIColor>
996 Upgraded from version 1.12 to 2.01.
998 =item C<Term::ReadLine>
1000 Upgraded from version 1.03 to 1.04.
1004 Upgraded from version 0.18 to 0.20.
1006 =item C<Test::Harness>
1008 Upgraded from version 2.64 to 3.17.
1010 Note that one side-effect of the 2.x to 3.x upgrade is that the
1011 experimental C<Test::Harness::Straps> module (and its supporting
1012 C<Assert>, C<Iterator>, C<Point> and C<Results> modules) have been
1013 removed. If you still need this, then they are available in the
1014 (unmaintained) C<Test-Harness-Straps> distribution on CPAN.
1016 =item C<Test::Simple>
1018 Upgraded from version 0.72 to 0.92.
1020 =item C<Text::ParseWords>
1022 Upgraded from version 3.26 to 3.27.
1026 Upgraded from version 2007.1117 to 2009.0305.
1030 Upgraded from version 2006.1117 to 2009.0305.
1032 =item C<Thread::Queue>
1034 Upgraded from version 2.00 to 2.11.
1036 =item C<Thread::Semaphore>
1038 Upgraded from version 2.01 to 2.09.
1042 Upgraded from version 1.67 to 1.73.
1044 =item C<threads::shared>
1046 Upgraded from version 1.14 to 1.29.
1048 =item C<Tie::RefHash>
1050 Upgraded from version 1.37 to 1.38.
1052 =item C<Tie::StdHandle>
1054 This has documentation changes, and has been assigned a version for the
1055 first time: version 4.2.
1057 =item C<Time::HiRes>
1059 Upgraded from version 1.9711 to 1.9719.
1061 =item C<Time::Local>
1063 Upgraded from version 1.18 to 1.1901.
1065 =item C<Time::Piece>
1067 Upgraded from version 1.12 to 1.15.
1069 =item C<Unicode::Normalize>
1071 Upgraded from version 1.02 to 1.03.
1073 =item C<Unicode::UCD>
1075 Upgraded from version 0.25 to 0.27.
1077 C<charinfo()> now works on Unified CJK code points added to later versions
1080 C<casefold()> has new fields returned to provide both a simpler interface
1081 and previously missing information. The old fields are retained for
1082 backwards compatibility. Information about Turkic-specific code points is
1085 The documentation has been corrected and expanded.
1089 Upgraded from version 1.04 to 1.05.
1091 C<< UNIVERSAL->import() >> is now deprecated.
1095 Upgraded from version 0.34 to 0.39.
1097 =item C<Win32API::File>
1099 Upgraded from version 0.1001_01 to 0.1101.
1103 Upgraded from version 0.08 to 0.10.
1105 =item Upgrade to Class::ISA 0.34
1107 =item Upgrade to Attribute::Handlers 0.87
1109 =item Upgrade to AutoLoader 5.70
1111 =item Upgrade to IO::Zlib 1.10
1113 =item Update parent to CPAN version 0.223
1115 =item Update Log::Message::Simple to CPAN version 0.06
1117 =item Updated Math::BigRat to CPAN version 0.24
1119 =item Update Archive::Tar to CPAN version 1.54
1121 =item Update IPC::Cmd to CPAN version 0.50
1123 =item Updated CPANPLUS::Dist::Build to CPAN version 0.40
1125 =item Updated Module::Loaded to CPAN version 0.06
1127 =item Upgrade Term::ANSIColor to 2.02
1129 =item Update Text::Balanced to 2.02
1131 =item Update Module::Build to 0.35
1133 =item constant has been upgraded to 1.19.
1135 =item upgrade CGI from 3.43 to 3.45
1137 =item bump Safe version to 2.18
1139 =item Upgrade to threads::shared 1.31
1141 =item Update threads to 1.74
1143 =item autodie 2.06_01
1145 =item Synchronize with CPAN's Attribute::Handlers 0.86
1147 =item Synchronize AutoLoader with CPAN's 5.69
1149 =item ExtUtils::MakeMaker 6.55_02
1151 =item Final release of version-0.77 for inclusion in 5.10.1
1153 =item Upgrade to Encode 2.37
1155 =item Upgrade to Class::ISA 0.36 (Fixes installation directories only)
1157 =item Upgrade to PathTools 3.30_02 (with only core reorganization fixes)
1161 =head1 Utility Changes
1167 Now looks in C<include-fixed> too, which is a recent addition to gcc's
1172 No longer incorrectly treats enum values like macros (Daniel Burr).
1174 Now handles C++ style constants (C<//>) properly in enums. (A patch from
1175 Rainer Weikusat was used; Daniel Burr also proposed a similar fix).
1179 C<LVALUE> subroutines now work under the debugger.
1181 The debugger now correctly handles proxy constant subroutines, and
1186 F<perlbug> now uses C<%Module::CoreList::bug_tracker> to print out upstream bug
1189 Where the user names a module that their bug report is about, and we know the
1190 URL for its upstream bug tracker, provide a message to the user explaining
1191 that the core copies the CPAN version directly, and provide the URL for
1192 reporting the bug directly to upstream.
1196 Perl 5.11.0 added a new utility F<perlthanks>, which is a variant of
1197 F<perlbug>, but for sending non-bug-reports to the authors and maintainers
1198 of Perl. Getting nothing but bug reports can become a bit demoralising:
1199 we'll see if this changes things.
1203 =head1 New Documentation
1209 This contains instructions on how to build perl for the Haiku platform.
1213 This describes the new interface for pluggable Method Resolution Orders.
1217 This document, by Richard Foley, provides an introduction to the use of
1218 performance and optimization techniques which can be used with particular
1219 reference to perl programs.
1221 =item L<perlrepository>
1223 This describes how to access the perl source using the I<git> version
1228 This describes the new F<perlthanks> utility.
1232 =head1 Changes to Existing Documentation
1234 The various large F<Changes*> files (which listed every change made to perl
1235 over the last 18 years) have been removed, and replaced by a small file,
1236 also called F<Changes>, which just explains how that same information may
1237 be extracted from the git version control system.
1239 The file F<Porting/patching.pod> has been deleted, as it mainly described
1240 interacting with the old Perforce-based repository, which is now obsolete.
1241 Information still relevant has been moved to L<perlrepository>.
1243 L<perlapi>, L<perlintern>, L<perlmodlib> and L<perltoc> are now all
1244 generated at build time, rather than being shipped as part of the release.
1250 Documented -X overloading.
1254 Documented that C<when()> treats specially most of the filetest operators
1258 Documented when as a syntax modifier
1262 Eliminated "Old Perl threads tutorial", which describes 5005 threads.
1264 F<pod/perlthrtut.pod> is the same material reworked for ithreads.
1268 Correct previous documentation: v-strings are not deprecated
1270 With version objects, we need them to use MODULE VERSION syntax. This
1271 patch removes the deprecation note.
1275 Added security contact information to L<perlsec>
1279 =head1 Performance Enhancements
1286 A new internal cache means that C<isa()> will often be faster.
1290 The implementation of C<C3> Method Resolution Order has been optimised -
1291 linearisation for classes with single inheritance is 40% faster. Performance
1292 for multiple inheritance is unchanged.
1296 Under C<use locale>, the locale-relevant information is now cached on
1297 read-only values, such as the list returned by C<keys %hash>. This makes
1298 operations such as C<sort keys %hash> in the scope of C<use locale> much
1303 Empty C<DESTROY> methods are no longer called.
1307 Faster C<Perl_sv_utf8_upgrade()>
1311 Speed up C<keys> on empty hash
1315 =head1 Installation and Configuration Improvements
1317 =head2 F<ext/> reorganisation
1319 The layout of directories in F<ext> has been revised. Specifically, all
1320 extensions are now flat, and at the top level, with C</> in pathnames
1321 replaced by C<->, so that F<ext/Data/Dumper/> is now F<ext/Data-Dumper/>,
1322 etc. The names of the extensions as specified to F<Configure>, and as
1323 reported by C<%Config::Config> under the keys C<dynamic_ext>,
1324 C<known_extensions>, C<nonxs_ext> and C<static_ext> have not changed, and
1325 still use C</>. Hence this change will not have any affect once perl is
1326 installed. C<Safe> has been split out from being part of C<Opcode>, and
1327 C<mro> is now an extension in its own right.
1329 Nearly all dual-life modules have been moved from F<lib> to F<ext>, and will
1330 now appear as known C<nonxs_ext>. This will made no difference to the
1331 structure of an installed perl, nor will the modules installed differ,
1332 unless you run F<Configure> with options to specify an exact list of
1333 extensions to build. In this case, you will rapidly become aware that you
1334 need to add to your list, because various modules needed to complete the
1335 build, such as C<ExtUtils::ParseXS>, have now become extensions, and
1336 without them the build will fail well before it attempts to run the
1339 =head2 Configuration improvements
1341 If C<vendorlib> and C<vendorarch> are the same, then they are only added to
1344 C<$Config{usedevel}> and the C-level C<PERL_USE_DEVEL> are now defined if
1345 perl is built with C<-Dusedevel>.
1347 F<Configure> will enable use of C<-fstack-protector>, to provide protection
1348 against stack-smashing attacks, if the compiler supports it.
1350 F<Configure> will now determine the correct prototypes for re-entrant
1351 functions, and for C<gconvert>, if you are using a C++ compiler rather
1354 On Unix, if you build from a tree containing a git repository, the
1355 configuration process will note the commit hash you have checked out, for
1356 display in the output of C<perl -v> and C<perl -V>. Unpushed local commits
1357 are automatically added to the list of local patches displayed by
1360 =head2 Compilation improvements
1362 As part of the flattening of F<ext>, all extensions on all platforms are
1363 built by F<make_ext.pl>. This replaces the Unix-specific
1364 F<ext/util/make_ext>, VMS-specific F<make_ext.com> and Win32-specific
1365 F<win32/buildext.pl>.
1367 =head2 Platform Specific Changes
1373 Removed F<libbsd> for AIX 5L and 6.1. Only C<flock()> was used from F<libbsd>.
1375 Removed F<libgdbm> for AIX 5L and 6.1. The F<libgdbm> is delivered as an
1376 optional package with the AIX Toolbox. Unfortunately the 64 bit version
1379 Hints changes mean that AIX 4.2 should work again.
1383 On Cygwin we now strip the last number from the DLL. This has been the
1384 behaviour in the cygwin.com build for years. The hints files have been
1389 Support for Apollo DomainOS was removed in Perl 5.11.0
1393 The hints files now identify the correct threading libraries on FreeBSD 7
1398 We now work around a bizarre preprocessor bug in the Irix 6.5 compiler:
1399 C<cc -E -> unfortunately goes into K&R mode, but C<cc -E file.c> doesn't.
1403 Patches from the Haiku maintainers have been merged in. Perl should now
1408 Support for Atari MiNT was removed in Perl 5.11.0.
1412 Perl should now build on MirOS BSD.
1416 Hints now supports versions 5.*.
1420 Various changes from Stratus have been merged in.
1424 There is now support for Symbian S60 3.2 SDK and S60 5.0 SDK.
1428 Improved message window handling means that C<alarm> and C<kill> messages
1429 will no longer be dropped under race conditions.
1433 Reads from the in-memory temporary files of C<PerlIO::scalar> used to fail
1434 if C<$/> was set to a numeric reference (to indicate record-style reads).
1437 VMS now supports C<getgrgid>.
1439 Many improvements and cleanups have been made to the VMS file name handling
1440 and conversion code.
1442 Enabling the C<PERL_VMS_POSIX_EXIT> logical name now encodes a POSIX exit
1443 status in a VMS condition value for better interaction with GNV's bash
1444 shell and other utilities that depend on POSIX exit values. See
1445 L<perlvms/"$?"> for details.
1447 C<File::Copy> now detects Unix compatibility mode on VMS.
1451 =head1 Selected Bug Fixes
1457 C<-I> on shebang line now adds directories in front of @INC
1458 as documented, and as does C<-I> when specified on the command-line.
1462 C<kill> is now fatal when called on non-numeric process identifiers.
1463 Previously, an 'undef' process identifier would be interpreted as a request to
1464 kill process "0", which would terminate the current process group on POSIX
1465 systems. Since process identifiers are always integers, killing a non-numeric
1466 process is now fatal.
1470 5.10.0 inadvertently disabled an optimisation, which caused a measurable
1471 performance drop in list assignment, such as is often used to assign
1472 function parameters from C<@_>. The optimisation has been re-instated, and
1473 the performance regression fixed.
1477 Fixed memory leak on C<while (1) { map 1, 1 }> [RT #53038].
1481 Some potential coredumps in PerlIO fixed [RT #57322,54828].
1485 The debugger now works with lvalue subroutines.
1489 The debugger's C<m> command was broken on modules that defined constants
1494 C<crypt> and string complement could return tainted values for untainted
1495 arguments [RT #59998].
1499 The C<-i>I<.suffix> command-line switch now recreates the file using
1500 restricted permissions, before changing its mode to match the original
1501 file. This eliminates a potential race condition [RT #60904].
1505 On some UNIX systems, the value in C<$?> would not have the top bit set
1506 (C<$? & 128>) even if the child core dumped.
1510 Under some circumstances, C<$^R> could incorrectly become undefined
1515 In the XS API, various hash functions, when passed a pre-computed hash where
1516 the key is UTF-8, might result in an incorrect lookup.
1520 XS code including F<XSUB.h> before F<perl.h> gave a compile-time error
1525 C<< $object->isa('Foo') >> would report false if the package C<Foo> didn't
1526 exist, even if the object's C<@ISA> contained C<Foo>.
1530 Various bugs in the new-to 5.10.0 mro code, triggered by manipulating
1531 C<@ISA>, have been found and fixed.
1535 Bitwise operations on references could crash the interpreter, e.g.
1536 C<$x=\$y; $x |= "foo"> [RT #54956].
1540 Patterns including alternation might be sensitive to the internal UTF-8
1541 representation, e.g.
1543 my $byte = chr(192);
1544 my $utf8 = chr(192); utf8::upgrade($utf8);
1545 $utf8 =~ /$byte|X}/i; # failed in 5.10.0
1549 Within UTF8-encoded Perl source files (i.e. where C<use utf8> is in
1550 effect), double-quoted literal strings could be corrupted where a C<\xNN>,
1551 C<\0NNN> or C<\N{}> is followed by a literal character with ordinal value
1552 greater than 255 [RT #59908].
1556 C<B::Deparse> failed to correctly deparse various constructs:
1557 C<readpipe STRING> [RT #62428], C<CORE::require(STRING)> [RT #62488],
1558 C<sub foo(_)> [RT #62484].
1562 Using C<setpgrp> with no arguments could corrupt the perl stack.
1566 The block form of C<eval> is now specifically trappable by C<Safe> and
1567 C<ops>. Previously it was erroneously treated like string C<eval>.
1571 In 5.10.0, the two characters C<[~> were sometimes parsed as the smart
1572 match operator (C<~~>) [RT #63854].
1576 In 5.10.0, the C<*> quantifier in patterns was sometimes treated as
1577 C<{0,32767}> [RT #60034, #60464]. For example, this match would fail:
1579 ("ab" x 32768) =~ /^(ab)*$/
1583 C<shmget> was limited to a 32 bit segment size on a 64 bit OS [RT #63924].
1587 Using C<next> or C<last> to exit a C<given> block no longer produces a
1588 spurious warning like the following:
1590 Exiting given via last at foo.pl line 123
1594 On Windows, C<'.\foo'> and C<'..\foo'> were treated differently than
1595 C<'./foo'> and C<'../foo'> by C<do> and C<require> [RT #63492].
1599 Assigning a format to a glob could corrupt the format; e.g.:
1601 *bar=*foo{FORMAT}; # foo format now bad
1605 Attempting to coerce a typeglob to a string or number could cause an
1606 assertion failure. The correct error message is now generated,
1607 C<Can't coerce GLOB to I<$type>>.
1611 Under C<use filetest 'access'>, C<-x> was using the wrong access mode. This
1612 has been fixed [RT #49003].
1616 C<length> on a tied scalar that returned a Unicode value would not be
1617 correct the first time. This has been fixed.
1621 Using an array C<tie> inside in array C<tie> could SEGV. This has been
1626 A race condition inside C<PerlIOStdio_close()> has been identified and
1627 fixed. This used to cause various threading issues, including SEGVs.
1631 In C<unpack>, the use of C<()> groups in scalar context was internally
1632 placing a list on the interpreter's stack, which manifested in various
1633 ways, including SEGVs. This is now fixed [RT #50256].
1637 Magic was called twice in C<substr>, C<\&$x>, C<tie $x, $m> and C<chop>.
1638 These have all been fixed.
1642 A 5.10.0 optimisation to clear the temporary stack within the implicit
1643 loop of C<s///ge> has been reverted, as it turned out to be the cause of
1644 obscure bugs in seemingly unrelated parts of the interpreter [commit
1649 The line numbers for warnings inside C<elsif> are now correct.
1653 The C<..> operator now works correctly with ranges whose ends are at or
1654 close to the values of the smallest and largest integers.
1658 C<binmode STDIN, ':raw'> could lead to segmentation faults on some platforms.
1659 This has been fixed [RT #54828].
1663 An off-by-one error meant that C<index $str, ...> was effectively being
1664 executed as C<index "$str\0", ...>. This has been fixed [RT #53746].
1668 Various leaks associated with named captures in regexes have been fixed
1673 A weak reference to a hash would leak. This was affecting C<DBI>
1678 Using (?|) in a regex could cause a segfault [RT #59734].
1682 Use of a UTF-8 C<tr//> within a closure could cause a segfault [RT #61520].
1686 Calling C<Perl_sv_chop()> or otherwise upgrading an SV could result in an
1687 unaligned 64-bit access on the SPARC architecture [RT #60574].
1691 In the 5.10.0 release, C<inc_version_list> would incorrectly list
1692 C<5.10.*> after C<5.8.*>; this affected the C<@INC> search order
1697 In 5.10.0, C<pack "a*", $tainted_value> returned a non-tainted value
1702 In 5.10.0, C<printf> and C<sprintf> could produce the fatal error
1703 C<panic: utf8_mg_pos_cache_update> when printing UTF-8 strings
1708 In the 5.10.0 release, a dynamically created C<AUTOLOAD> method might be
1709 missed (method cache issue) [RT #60220,60232].
1713 In the 5.10.0 release, a combination of C<use feature> and C<//ee> could
1714 cause a memory leak [RT #63110].
1718 C<-C> on the shebang (C<#!>) line is once more permitted if it is also
1719 specified on the command line. C<-C> on the shebang line used to be a
1720 silent no-op I<if> it was not also on the command line, so perl 5.10.0
1721 disallowed it, which broke some scripts. Now perl checks whether it is
1722 also on the command line and only dies if it is not [RT #67880].
1726 In 5.10.0, certain types of re-entrant regular expression could crash,
1727 or cause the following assertion failure [RT #60508]:
1729 Assertion rx->sublen >= (s - rx->subbeg) + i failed
1733 Previously missing files from Unicode 5.1 Character Database are now included.
1737 C<TMPDIR> is now honored when opening an anonymous temporary file
1741 =head1 New or Changed Diagnostics
1745 =item C<panic: sv_chop %s>
1747 This new fatal error occurs when the C routine C<Perl_sv_chop()> was
1748 passed a position that is not within the scalar's string buffer. This
1749 could be caused by buggy XS code, and at this point recovery is not
1752 =item C<Can't locate package %s for the parents of %s>
1754 This warning has been removed. In general, it only got produced in
1755 conjunction with other warnings, and removing it allowed an ISA lookup
1756 optimisation to be added.
1758 =item C<v-string in use/require is non-portable>
1760 This warning has been removed.
1762 =item C<Deep recursion on subroutine "%s">
1764 It is now possible to change the depth threshold for this warning from the
1765 default of 100, by recompiling the F<perl> binary, setting the C
1766 pre-processor macro C<PERL_SUB_DEPTH_WARN> to the desired value.
1770 =head1 Changed Internals
1776 TODO: C<SVt_RV> is gone. RVs are now stored in IVs
1780 TODO: REGEXPs are first class
1784 TODO: OOK is reworked, such that an OOKed scalar is PV not PVIV
1788 The J.R.R. Tolkien quotes at the head of C source file have been checked and
1789 proper citations added, thanks to a patch from Tom Christiansen.
1793 C<Perl_vcroak()> now accepts a null first argument. In addition, a full audit
1794 was made of the "not NULL" compiler annotations, and those for several
1795 other internal functions were corrected.
1799 New macros C<dSAVEDERRNO>, C<dSAVE_ERRNO>, C<SAVE_ERRNO>, C<RESTORE_ERRNO>
1800 have been added to formalise the temporary saving of the C<errno>
1805 The function C<Perl_sv_insert_flags> has been added to augment
1810 The function C<Perl_newSV_type(type)> has been added, equivalent to
1811 C<Perl_newSV()> followed by C<Perl_sv_upgrade(type)>.
1815 The function C<Perl_newSVpvn_flags()> has been added, equivalent to
1816 C<Perl_newSVpvn()> and then performing the action relevant to the flag.
1818 Two flag bits are currently supported.
1824 This will call C<SvUTF8_on()> for you. (Note that this does not convert an
1825 sequence of ISO 8859-1 characters to UTF-8). A wrapper, C<newSVpvn_utf8()>
1826 is available for this.
1830 Call C<Perl_sv_2mortal()> on the new SV.
1834 There is also a wrapper that takes constant strings, C<newSVpvs_flags()>.
1838 The function C<Perl_croak_xs_usage> has been added as a wrapper to
1843 The functions C<PerlIO_find_layer> and C<PerlIO_list_alloc> are now
1848 C<PL_na> has been exterminated from the core code, replaced by local STRLEN
1849 temporaries, or C<*_nolen()> calls. Either approach is faster than C<PL_na>,
1850 which is a pointer deference into the interpreter structure under ithreads,
1851 and a global variable otherwise.
1855 C<Perl_mg_free()> used to leave freed memory accessible via C<SvMAGIC()> on
1856 the scalar. It now updates the linked list to remove each piece of magic
1861 Under ithreads, the regex in C<PL_reg_curpm> is now reference counted. This
1862 eliminates a lot of hackish workarounds to cope with it not being reference
1867 C<Perl_mg_magical()> would sometimes incorrectly turn on C<SvRMAGICAL()>.
1868 This has been fixed.
1872 The I<public> IV and NV flags are now not set if the string value has
1873 trailing "garbage". This behaviour is consistent with not setting the
1874 public IV or NV flags if the value is out of range for the type.
1878 SV allocation tracing has been added to the diagnostics enabled by C<-Dm>.
1879 The tracing can alternatively output via the C<PERL_MEM_LOG> mechanism, if
1880 that was enabled when the F<perl> binary was compiled.
1884 Smartmatch resolution tracing has been added as a new diagnostic. Use C<-DM> to
1890 A new debugging flag C<-DB> now dumps subroutine definitions, leaving
1891 C<-Dx> for its original purpose of dumping syntax trees.
1895 Uses of C<Nullav>, C<Nullcv>, C<Nullhv>, C<Nullop>, C<Nullsv> etc have been
1896 replaced by C<NULL> in the core code, and non-dual-life modules, as C<NULL>
1897 is clearer to those unfamiliar with the core code.
1901 A macro C<MUTABLE_PTR(p)> has been added, which on (non-pedantic) gcc will
1902 not cast away C<const>, returning a C<void *>. Macros C<MUTABLE_SV(av)>,
1903 C<MUTABLE_SV(cv)> etc build on this, casting to C<AV *> etc without
1904 casting away C<const>. This allows proper compile-time auditing of
1905 C<const> correctness in the core, and helped picked up some errors (now
1910 Macros C<mPUSHs()> and C<mXPUSHs()> have been added, for pushing SVs on the
1911 stack and mortalizing them.
1915 Use of the private structure C<mro_meta> has changed slightly. Nothing
1916 outside the core should be accessing this directly anyway.
1920 A new tool, F<Porting/expand-macro.pl> has been added, that allows you
1921 to view how a C preprocessor macro would be expanded when compiled.
1922 This is handy when trying to decode the macro hell that is the perl
1929 Many modules updated from CPAN incorporate new tests.
1931 Several tests that have the potential to hang forever if they fail now
1932 incorporate a "watchdog" functionality that will kill them after a timeout,
1933 which helps ensure that C<make test> and C<make test_harness> run to
1934 completion automatically. (Jerry Hedden).
1936 Some core-specific tests have been added:
1940 =item t/comp/retainedlines.t
1942 Check that the debugger can retain source lines from C<eval>.
1944 =item t/io/perlio_fail.t
1946 Check that bad layers fail.
1948 =item t/io/perlio_leaks.t
1950 Check that PerlIO layers are not leaking.
1952 =item t/io/perlio_open.t
1954 Check that certain special forms of open work.
1958 General PerlIO tests.
1962 Check that there is no unexpected interaction between the internal types
1963 C<PVBM> and C<PVGV>.
1965 =item t/mro/package_aliases.t
1967 Check that mro works properly in the presence of aliased packages.
1971 Tests for C<dbmopen> and C<dbmclose>.
1973 =item t/op/index_thr.t
1975 Tests for the interaction of C<index> and threads.
1977 =item t/op/pat_thr.t
1979 Tests for the interaction of esoteric patterns and threads.
1983 Test that C<qr> doesn't leak.
1985 =item t/op/reg_email_thr.t
1987 Tests for the interaction of regex recursion and threads.
1989 =item t/op/regexp_qr_embed_thr.t
1991 Tests for the interaction of patterns with embedded C<qr//> and threads.
1993 =item t/op/regexp_unicode_prop.t
1995 Tests for Unicode properties in regular expressions.
1997 =item t/op/regexp_unicode_prop_thr.t
1999 Tests for the interaction of Unicode properties and threads.
2001 =item t/op/reg_nc_tie.t
2003 Test the tied methods of C<Tie::Hash::NamedCapture>.
2005 =item t/op/reg_posixcc.t
2007 Check that POSIX character classes behave consistently.
2011 Check that exportable C<re> functions in F<universal.c> work.
2013 =item t/op/setpgrpstack.t
2015 Check that C<setpgrp> works.
2017 =item t/op/substr_thr.t
2019 Tests for the interaction of C<substr> and threads.
2021 =item t/op/upgrade.t
2023 Check that upgrading and assigning scalars works.
2025 =item t/uni/lex_utf8.t
2027 Check that Unicode in the lexer works.
2031 Check that Unicode and C<tie> work.
2035 =head1 Known Problems
2037 This is a list of some significant unfixed bugs, which are regressions
2038 from either 5.10.0 or 5.8.x.
2044 C<List::Util::first> misbehaves in the presence of a lexical C<$_>
2045 (typically introduced by C<my $_> or implicitly by C<given>). The variable
2046 which gets set for each iteration is the package variable C<$_>, not the
2047 lexical C<$_> [RT #67694].
2049 A similar issue may occur in other modules that provide functions which
2050 take a block as their first argument, like
2052 foo { ... $_ ...} list
2056 The C<charnames> pragma may generate a run-time error when a regex is
2057 interpolated [RT #56444]:
2059 use charnames ':full';
2060 my $r1 = qr/\N{THAI CHARACTER SARA I}/;
2061 "foo" =~ $r1; # okay
2062 "foo" =~ /$r1+/; # runtime error
2064 A workaround is to generate the character outside of the regex:
2066 my $a = "\N{THAI CHARACTER SARA I}";
2071 Some regexes may run much more slowly when run in a child thread compared
2072 with the thread the pattern was compiled into [RT #55600].
2078 The following items are now deprecated.
2084 C<Switch> is buggy and should be avoided. From perl 5.11.0 onwards, it is
2085 intended that any use of the core version of this module will emit a
2086 warning, and that the module will eventually be removed from the core
2087 (probably in perl 5.14.0). See L<perlsyn/"Switch statements"> for its
2092 The following modules will be removed from the core distribution in a future
2093 release, and should be installed from CPAN instead. Distributions on CPAN
2094 which require these should add them to their prerequisites. The core versions
2095 of these modules warnings will issue a deprecation warning.
2113 Currently support to install from CPAN without a I<force> is C<TODO> in CPAN
2114 and CPANPLUS. This will be addressed before 5.12.0 ships.
2118 C<suidperl> has been removed. It used to provide a mechanism to
2119 emulate setuid permission bits on systems that don't support it properly.
2123 Deprecate assignment to $[
2127 Remove attrs, which has been deprecated since 1999/10/02.
2131 Deprecate use of the attribute :locked on subroutines.
2135 Deprecate using "locked" with the attributes pragma.
2139 Deprecate using "unique" with the attributes pragma.
2143 warn if ++ or -- are unable to change the value because it's beyond the limit of representation
2145 This uses a new warnings category: "imprecision".
2149 Make lc/uc/lcfirst/ucfirst warn when passed undef.
2153 Show constant in "Useless use of a constant in void context"
2157 Make the new warning report undef constants as undef
2161 Add a new warning, "Prototype after '%s'"
2165 Tweak the "Illegal character in prototype" warning so it's more precise when reporting illegal characters after _
2169 Unintented interpolation of $\ in regex
2173 Make overflow warnings in gmtime/localtime only occur when warnings are on
2177 Improve mro merging error messages.
2179 They are now very similar to those produced by Algorithm::C3.
2183 Amelioration of the error message "Unrecognized character %s in column %d"
2185 Changes the error message to "Unrecognized character %s; marked by <--
2186 HERE after %s<-- HERE near column %d". This should make it a little
2187 simpler to spot and correct the suspicious character.
2191 Explicitely point to $. when it causes an uninitialized warning for ranges in scalar context
2195 Removed vestigal support for Tenon Intersystems MachTen Unix layer for MacOS Classic.
2199 Removed the port to Atari MiNT. It's a dead platform that hasn't had any love since 5.005.
2204 Deprecated numerous Perl 4-era libraries:
2206 F<termcap.pl>, F<tainted.pl>, F<stat.pl>, F<shellwords.pl>, F<pwd.pl>,
2207 F<open3.pl>, F<open2.pl>, F<newgetopt.pl>, F<look.pl>, F<find.pl>,
2208 F<finddepth.pl>, F<importenv.pl>, F<hostname.pl>, F<getopts.pl>,
2209 F<getopt.pl>, F<getcwd.pl>, F<flush.pl>, F<fastcwd.pl>, F<exceptions.pl>,
2210 F<ctime.pl>, F<complete.pl>, F<cacheout.pl>, F<bigrat.pl>, F<bigint.pl>,
2211 F<bigfloat.pl>, F<assert.pl>, F<abbrev.pl>, F<dotsh.pl>, and
2212 F<timelocal.pl> are all now deprecated. Using them will incur a warning.
2216 =head1 Acknowledgements
2218 Some of the work in this release was funded by a TPF grant funded by
2219 Dijkmat BV, The Netherlands.
2221 Steffen Mueller and David Golden in particular helped getting CPAN modules
2222 polished and synchronised with their in-core equivalents.
2224 Craig Berry was tireless in getting maint to run under VMS, no matter how
2225 many times we broke it for him.
2227 The other core committers contributed most of the changes, and applied most
2228 of the patches sent in by the hundreds of contributors listed in F<AUTHORS>.
2230 Much of the work of categorizing changes in this perldelta file was contributed
2231 by the following porters using changelogger.bestpractical.com:
2233 Nicholas Clark, leon, shawn, alexm, rjbs, rafl, Pedro Melo, brunorc,
2234 anonymous, ☄, Tom Hukins, anonymous, Jesse, dagolden, Moritz Onken,
2235 Mark Fowler, chorny, anonymous, tmtm
2237 Finally, thanks to Larry Wall, without whom none of this would be
2240 =head1 Reporting Bugs
2242 If you find what you think is a bug, you might check the articles
2243 recently posted to the comp.lang.perl.misc newsgroup and the perl
2244 bug database at http://rt.perl.org/perlbug/ . There may also be
2245 information at http://www.perl.org/ , the Perl Home Page.
2247 If you believe you have an unreported bug, please run the B<perlbug>
2248 program included with your release. Be sure to trim your bug down
2249 to a tiny but sufficient test case. Your bug report, along with the
2250 output of C<perl -V>, will be sent off to perlbug@perl.org to be
2251 analysed by the Perl porting team.
2253 If the bug you are reporting has security implications, which make it
2254 inappropriate to send to a publicly archived mailing list, then please send
2255 it to perl5-security-report@perl.org. This points to a closed subscription
2256 unarchived mailing list, which includes all the core committers, who be able
2257 to help assess the impact of issues, figure out a resolution, and help
2258 co-ordinate the release of patches to mitigate or fix the problem across all
2259 platforms on which Perl is supported. Please only use this address for
2260 security issues in the Perl core, not for modules independently
2261 distributed on CPAN.
2265 The F<Changes> file for an explanation of how to view exhaustive details
2268 The F<INSTALL> file for how to build Perl.
2270 The F<README> file for general stuff.
2272 The F<Artistic> and F<Copying> files for copyright information.