+=encoding utf8
+
=head1 NAME
-perldelta - what is new for perl v5.11.0
+perl5110delta - what is new for perl v5.11.0
+
+=head1 DESCRIPTION
+
+This document describes differences between the 5.10.0 release and
+the 5.11.0 development release.
+
+=head1 Incompatible Changes
+
+=head2 In @INC, move ARCHLIB and PRIVLIB after the current version's site_perl and vendor_perl.
+
+=head2 Switch statement changes
+
+The handling of complex expressions by the C<given>/C<when> switch
+statement has been enhanced. These enhancements are also available in
+5.10.1 and subsequent 5.10 releases. There are two new cases where C<when> now
+interprets its argument as a boolean, instead of an expression to be used
+in a smart match:
+
+=over 4
+
+=item flip-flop operators
+
+The C<..> and C<...> flip-flop operators are now evaluated in boolean
+context, following their usual semantics; see L<perlop/"Range Operators">.
+
+Note that, as in perl 5.10.0, C<when (1..10)> will not work to test
+whether a given value is an integer between 1 and 10; you should use
+C<when ([1..10])> instead (note the array reference).
+
+However, contrary to 5.10.0, evaluating the flip-flop operators in boolean
+context ensures it can now be useful in a C<when()>, notably for
+implementing bistable conditions, like in:
+
+ when (/^=begin/ .. /^=end/) {
+ # do something
+ }
+
+=item defined-or operator
+
+A compound expression involving the defined-or operator, as in
+C<when (expr1 // expr2)>, will be treated as boolean if the first
+expression is boolean. (This just extends the existing rule that applies
+to the regular or operator, as in C<when (expr1 || expr2)>.)
+
+=back
+
+The next section details more changes brought to the semantics to
+the smart match operator, that naturally also modify the behaviour
+of the switch statements where smart matching is implicitly used.
+These changers were also made for the 5.10.1 release, and will remain in
+subsequent 5.10 releases.
+
+=head2 Smart match changes
+
+=head3 Changes to type-based dispatch
+
+The smart match operator C<~~> is no longer commutative. The behaviour of
+a smart match now depends primarily on the type of its right hand
+argument. Moreover, its semantics have been adjusted for greater
+consistency or usefulness in several cases. While the general backwards
+compatibility is maintained, several changes must be noted:
+
+=over 4
+
+=item *
+
+Code references with an empty prototype are no longer treated specially.
+They are passed an argument like the other code references (even if they
+choose to ignore it).
+
+=item *
+
+C<%hash ~~ sub {}> and C<@array ~~ sub {}> now test that the subroutine
+returns a true value for each key of the hash (or element of the
+array), instead of passing the whole hash or array as a reference to
+the subroutine.
+
+=item *
+
+Due to the commutativity breakage, code references are no longer
+treated specially when appearing on the left of the C<~~> operator,
+but like any vulgar scalar.
+
+=item *
+
+C<undef ~~ %hash> is always false (since C<undef> can't be a key in a
+hash). No implicit conversion to C<""> is done (as was the case in perl
+5.10.0).
+
+=item *
+
+C<$scalar ~~ @array> now always distributes the smart match across the
+elements of the array. It's true if one element in @array verifies
+C<$scalar ~~ $element>. This is a generalization of the old behaviour
+that tested whether the array contained the scalar.
+
+=back
+
+The full dispatch table for the smart match operator is given in
+L<perlsyn/"Smart matching in detail">.
+
+=head3 Smart match and overloading
+
+According to the rule of dispatch based on the rightmost argument type,
+when an object overloading C<~~> appears on the right side of the
+operator, the overload routine will always be called (with a 3rd argument
+set to a true value, see L<overload>.) However, when the object will
+appear on the left, the overload routine will be called only when the
+rightmost argument is a simple scalar. This way distributivity of smart match
+across arrays is not broken, as well as the other behaviours with complex
+types (coderefs, hashes, regexes). Thus, writers of overloading routines
+for smart match mostly need to worry only with comparing against a scalar,
+and possibly with stringification overloading; the other common cases
+will be automatically handled consistently.
+
+C<~~> will now refuse to work on objects that do not overload it (in order
+to avoid relying on the object's underlying structure). (However, if the
+object overloads the stringification or the numification operators, and
+if overload fallback is active, it will be used instead, as usual.)
+
+=head2 Labels can't be keywords
+
+Labels used as targets for the C<goto>, C<last>, C<next> or C<redo>
+statements cannot be keywords anymore. This restriction will prevent
+potential confusion between the C<goto LABEL> and C<goto EXPR> syntaxes:
+for example, a statement like C<goto print> would jump to a label whose
+name would be the return value of print(), (usually 1), instead of a
+label named C<print>. Moreover, the other control flow statements
+would just ignore any keyword passed to them as a label name. Since
+such labels cannot be defined anymore, this kind of error will be
+avoided.
+
+=head2 Other incompatible changes
+
+=over 4
+
+=item *
+
+The semantics of C<use feature :5.10*> have changed slightly.
+See L<"Modules and Pragmata"> for more information.
+
+=item *
+
+It is now a run-time error to use the smart match operator C<~~>
+with an object that has no overload defined for it. (This way
+C<~~> will not break encapsulation by matching against the
+object's internal representation as a reference.)
+
+=item *
+
+The version control system used for the development of the perl
+interpreter has been switched from Perforce to git. This is mainly an
+internal issue that only affects people actively working on the perl core;
+but it may have minor external visibility, for example in some of details
+of the output of C<perl -V>. See L<perlrepository> for more information.
+
+=item *
+
+The internal structure of the C<ext/> directory in the perl source has
+been reorganised. In general, a module C<Foo::Bar> whose source was
+stored under F<ext/Foo/Bar/> is now located under F<ext/Foo-Bar/>. Also,
+some modules have been moved from F<lib/> to F<ext/>. This is purely a
+source tarball change, and should make no difference to the compilation or
+installation of perl, unless you have a very customised build process that
+explicitly relies on this structure, or which hard-codes the C<nonxs_ext>
+F<Configure> parameter. Specifically, this change does not by default
+alter the location of any files in the final installation.
+
+=item *
+
+As part of the C<Test::Harness> 2.x to 3.x upgrade, the experimental
+C<Test::Harness::Straps> module has been removed.
+See L</"Updated Modules"> for more details.
+
+=item *
+
+As part of the C<ExtUtils::MakeMaker> upgrade, the
+C<ExtUtils::MakeMaker::bytes> and C<ExtUtils::MakeMaker::vmsish> modules
+have been removed from this distribution.
+
+=item *
+
+C<Module::CoreList> no longer contains the C<%:patchlevel> hash.
+
+=item *
+
+This one is actually a change introduced in 5.10.0, but it was missed
+from that release's perldelta, so it is mentioned here instead.
+
+A bugfix related to the handling of the C</m> modifier and C<qr> resulted
+in a change of behaviour between 5.8.x and 5.10.0:
+
+ # matches in 5.8.x, doesn't match in 5.10.0
+ $re = qr/^bar/; "foo\nbar" =~ /$re/m;
+
+=item *
+
+C<length undef> now returns undef.
+
+=back
+
+=head1 Core Enhancements
+
+=head2 Unicode Character Database 5.1.0
+
+The copy of the Unicode Character Database included in Perl 5.11.0 has
+been updated to 5.1.0 from 5.0.0. See
+L<http://www.unicode.org/versions/Unicode5.1.0/#Notable_Changes> for the
+notable changes.
+
+=head2 A proper interface for pluggable Method Resolution Orders
+
+As of Perl 5.11.0 there is a new interface for plugging and using method
+resolution orders other than the default (linear depth first search).
+The C3 method resolution order added in 5.10.0 has been re-implemented as
+a plugin, without changing its Perl-space interface. See L<perlmroapi> for
+more information.
+
+=head2 The C<overloading> pragma
+
+This pragma allows you to lexically disable or enable overloading
+for some or all operations. (Yuval Kogman)
+
+=head2 C<\N> regex escape
+
+A new regex escape has been added, C<\N>. It will match any character that
+is not a newline, independently from the presence or absence of the single
+line match modifier C</s>. (If C<\N> is followed by an opening brace and
+by a letter, perl will still assume that a Unicode character name is
+coming, so compatibility is preserved.) (Rafael Garcia-Suarez)
+
+=head2 Implicit strictures
+
+Using the C<use VERSION> syntax with a version number greater or equal
+to 5.11.0 will also lexically enable strictures just like C<use strict>
+would do (in addition to enabling features.) So, the following:
+
+ use 5.11.0;
+
+will now imply:
+
+ use strict;
+ use feature ':5.11';
+
+=head2 Parallel tests
+
+The core distribution can now run its regression tests in parallel on
+Unix-like platforms. Instead of running C<make test>, set C<TEST_JOBS> in
+your environment to the number of tests to run in parallel, and run
+C<make test_harness>. On a Bourne-like shell, this can be done as
+
+ TEST_JOBS=3 make test_harness # Run 3 tests in parallel
+
+An environment variable is used, rather than parallel make itself, because
+L<TAP::Harness> needs to be able to schedule individual non-conflicting test
+scripts itself, and there is no standard interface to C<make> utilities to
+interact with their job schedulers.
+
+Note that currently some test scripts may fail when run in parallel (most
+notably C<ext/IO/t/io_dir.t>). If necessary run just the failing scripts
+again sequentially and see if the failures go away.
+
+=head2 The C<...> operator
+
+A new operator, C<...>, nicknamed the Yada Yada operator, has been added.
+It is intended to mark placeholder code, that is not yet implemented.
+See L<perlop/"Yada Yada Operator">. (chromatic)
+
+=head2 DTrace support
+
+Some support for DTrace has been added. See "DTrace support" in F<INSTALL>.
+
+=head2 Support for C<configure_requires> in CPAN module metadata
+
+Both C<CPAN> and C<CPANPLUS> now support the C<configure_requires> keyword
+in the F<META.yml> metadata file included in most recent CPAN distributions.
+This allows distribution authors to specify configuration prerequisites that
+must be installed before running F<Makefile.PL> or F<Build.PL>.
+
+See the documentation for C<ExtUtils::MakeMaker> or C<Module::Build> for more
+on how to specify C<configure_requires> when creating a distribution for CPAN.
+
+=head2 The C<each> function can now operate on arrays
+
+=head2 Perl's core time-related functions are now Y2038 compliand
+
+=head2 The variable C<$,> may now be tied
+
+=head2 // now behaves like || in when clauses
+
+=head2 You can now set C<-W> from the C<PERL5OPT> environment varialbe
+
+=head1 Modules and Pragmata
+
+=head2 New Modules and Pragmata
+
+=over 4
+
+=item C<autodie>
+
+This is a new lexically-scoped alternative for the C<Fatal> module.
+The bundled version is 2.06_01. Note that in this release, using a string
+eval when C<autodie> is in effect can cause the autodie behaviour to leak
+into the surrounding scope. See L<autodie/"BUGS"> for more details.
+
+=item C<Compress::Raw::Bzip2>
+
+This has been added to the core (version 2.020).
+
+=item C<parent>
+
+This pragma establishes an ISA relationship with base classes at compile
+time. It provides the key feature of C<base> without the feature creep.
+
+=item C<Parse::CPAN::Meta>
+
+This has been added to the core (version 1.39).
+
+=back
+
+=head2 Pragmata Changes
+
+=over 4
+
+=item C<overloading>
+
+See L</"The C<overloading> pragma"> above.
+
+=item C<attributes>
+
+Upgraded from version 0.08 to 0.09.
+
+=item C<attrs>
+
+The C<attrs> pragma has been removed. It had been marked as deprecated since
+5.6.0.
+
+=item C<base>
+
+Upgraded from version 2.13 to 2.14. See L<parent> for a replacement.
+
+=item C<bigint>
+
+Upgraded from version 0.22 to 0.23.
+
+=item C<bignum>
+
+Upgraded from version 0.22 to 0.23.
+
+=item C<bigrat>
+
+Upgraded from version 0.22 to 0.23.
+
+=item C<charnames>
+
+Upgraded from version 1.06 to 1.07.
+
+The Unicode F<NameAliases.txt> database file has been added. This has the
+effect of adding some extra C<\N> character names that formerly wouldn't
+have been recognised; for example, C<"\N{LATIN CAPITAL LETTER GHA}">.
+
+=item C<constant>
+
+Upgraded from version 1.13 to 1.19. Some code has been shifted from run time to
+compile time, and the amount of MRO cache flushing has been minimised.
+
+=item C<feature>
+
+The meaning of the C<:5.10> and C<:5.10.X> feature bundles has
+changed slightly. The last component, if any (i.e. C<X>) is simply ignored.
+This is predicated on the assumption that new features will not, in
+general, be added to maintenance releases. So C<:5.10> and C<:5.10.X>
+have identical effect. This is a change to the behaviour documented for
+5.10.0.
+
+=item C<fields>
+
+Upgraded from version 2.13 to 2.14 (this was just a version bump; there
+were no functional changes).
+
+=item C<lib>
+
+Upgraded from version 0.5565 to 0.62.
+
+=item C<open>
+
+Upgraded from version 1.06 to 1.07.
+
+=item C<overload>
+
+Upgraded from version 1.06 to 1.07.
+
+=item C<overloading>
+
+See L</"The C<overloading> pragma"> above.
+
+=item C<version>
+
+Upgraded from version 0.74 to 0.77.
+
+=back
+
+=head2 Updated Modules
+
+=over 4
+
+=item C<Archive::Extract>
+
+Upgraded from version 0.24 to 0.34.
+
+=item C<Archive::Tar>
+
+Upgraded from version 1.38 to 1.52.
+
+=item C<Attribute::Handlers>
+
+Upgraded from version 0.79 to 0.85.
+
+=item C<AutoLoader>
+
+Upgraded from version 5.63 to 5.68.
+
+=item C<AutoSplit>
+
+Upgraded from version 1.05 to 1.06.
+
+=item C<B>
+
+Upgraded from version 1.17 to 1.22.
+
+=item C<B::Debug>
+
+Upgraded from version 1.05 to 1.11.
+
+=item C<B::Deparse>
+
+Upgraded from version 0.83 to 0.89.
+
+=item C<B::Lint>
+
+Upgraded from version 1.09 to 1.11.
+
+=item C<B::Xref>
+
+Upgraded from version 1.01 to 1.02.
+
+=item C<Benchmark>
+
+Upgraded from version 1.10 to 1.11.
+
+=item C<Carp>
+
+Upgraded from version 1.08 to 1.11.
+
+L<Carp> now includes all the necessary code to function. Previously, it
+used to be a lightweight placeholder that loaded the actual code from
+C<Carp::Heavy> on demand. C<Carp::Heavy> is now a simple, empty module
+kept for backwards compatibility for programs that used to pre-load it.
+
+=item C<CGI>
+
+Upgraded from version 3.29 to 3.43.
+(also includes the "default_value for popup_menu()" fix from 3.45).
+
+=item C<Compress::Zlib>
+
+Upgraded from version 2.008 to 2.020.
+
+=item C<CPAN>
+
+Upgraded from version 1.9205 to 1.9402. C<CPAN::FTP> has a local fix to
+stop it being too verbose on download failure.
+
+=item C<CPANPLUS>
+
+Upgraded from version 0.84 to 0.88.
+
+=item C<CPANPLUS::Dist::Build>
+
+Upgraded from version 0.06_02 to 0.36.
+
+=item C<Cwd>
+
+Upgraded from version 3.25_01 to 3.30.
+
+=item C<Data::Dumper>
+
+Upgraded from version 2.121_14 to 2.124.
+
+=item C<DB>
+
+Upgraded from version 1.01 to 1.02.
+
+=item C<DB_File>
+
+Upgraded from version 1.816_1 to 1.820.
+
+=item C<Devel::PPPort>
+
+Upgraded from version 3.13 to 3.19.
+
+=item C<Digest::MD5>
+
+Upgraded from version 2.36_01 to 2.39.
+
+=item C<Digest::SHA>
+
+Upgraded from version 5.45 to 5.47.
+
+=item C<DirHandle>
+
+Upgraded from version 1.01 to 1.03.
+
+=item C<Dumpvalue>
+
+Upgraded from version 1.12 to 1.13.
+
+=item C<DynaLoader>
+
+Upgraded from version 1.08 to 1.10.
+
+=item C<Encode>
+
+Upgraded from version 2.23 to 2.35.
+
+=item C<Errno>
+
+Upgraded from version 1.10 to 1.11.
+
+=item C<Exporter>
+
+Upgraded from version 5.62 to 5.63.
+
+=item C<ExtUtils::CBuilder>
+
+Upgraded from version 0.21 to 0.2602.
+
+=item C<ExtUtils::Command>
+
+Upgraded from version 1.13 to 1.16.
+
+=item C<ExtUtils::Constant>
+
+Upgraded from 0.20 to 0.22. (Note that neither of these versions are
+available on CPAN.)
+
+=item C<ExtUtils::Embed>
+
+Upgraded from version 1.27 to 1.28.
+
+=item C<ExtUtils::Install>
+
+Upgraded from version 1.44 to 1.54.
+
+=item C<ExtUtils::MakeMaker>
+
+Upgraded from version 6.42 to 6.55_02.
+
+Note that C<ExtUtils::MakeMaker::bytes> and C<ExtUtils::MakeMaker::vmsish>
+have been removed from this distribution.
+
+=item C<ExtUtils::Manifest>
+
+Upgraded from version 1.51_01 to 1.56.
+
+=item C<ExtUtils::ParseXS>
+
+Upgraded from version 2.18_02 to 2.2002.
+
+=item C<Fatal>
+
+Upgraded from version 1.05 to 2.06_01. See also the new pragma C<autodie>.
+
+=item C<File::Basename>
+
+Upgraded from version 2.76 to 2.77.
+
+=item C<File::Compare>
+
+Upgraded from version 1.1005 to 1.1006.
+
+=item C<File::Copy>
+
+Upgraded from version 2.11 to 2.16.
+
+File::Copy now always return 0 (not "") on failure.
+
+FIXME - describe C<cp>
+
+=item C<File::Fetch>
+
+Upgraded from version 0.14 to 0.20.
+
+=item C<File::Find>
+
+Upgraded from version 1.12 to 1.14.
+
+=item C<File::Path>
+
+Upgraded from version 2.04 to 2.07_03.
+
+=item C<File::Spec>
+
+Upgraded from version 3.2501 to 3.30.
+
+=item C<File::stat>
+
+Upgraded from version 1.00 to 1.01.
+
+Added -X overloading, -M, -C and -A.
+
+=item C<File::Temp>
+
+Upgraded from version 0.18 to 0.22.
+
+=item C<FileCache>
+
+Upgraded from version 1.07 to 1.08.
+
+=item C<FileHandle>
+
+Upgraded from version 2.01 to 2.02.
+
+=item C<Filter::Simple>
+
+Upgraded from version 0.82 to 0.84.
+
+=item C<Filter::Util::Call>
+
+Upgraded from version 1.07 to 1.08.
+
+=item C<FindBin>
+
+Upgraded from version 1.49 to 1.50.
+
+=item C<GDBM_File>
+
+Upgraded from version 1.08 to 1.09.
+
+=item C<Getopt::Long>
+
+Upgraded from version 2.37 to 2.38.
+
+=item C<Hash::Util::FieldHash>
+
+Upgraded from version 1.03 to 1.04. This fixes a memory leak.
+
+=item C<I18N::Collate>
+
+Upgraded from version 1.00 to 1.01.
+
+=item C<IO>
+
+Upgraded from version 1.23_01 to 1.25.
+
+This makes non-blocking mode work on Windows in C<IO::Socket::INET>
+[CPAN #43573].
+
+=item C<IO::Compress::*>
+
+Upgraded from version 2.008 to 2.020.
+
+=item C<IO::Dir>
+
+Upgraded from version 1.06 to 1.07.
+
+=item C<IO::Handle>
+
+Upgraded from version 1.27 to 1.28.
+
+=item C<IO::Socket>
+
+Upgraded from version 1.30_01 to 1.31.
+
+=item C<IO::Zlib>
+
+Upgraded from version 1.07 to 1.09.
+
+=item C<IPC::Cmd>
+
+Upgraded from version 0.40_1 to 0.46.
+
+=item C<IPC::Open3>
+
+Upgraded from version 1.02 to 1.04.
+
+=item C<IPC::SysV>
+
+Upgraded from version 1.05 to 2.01.
+
+=item C<lib>
+
+Upgraded from version 0.5565 to 0.62.
+
+=item C<List::Util>
+
+Upgraded from version 1.19 to 1.21.
+
+=item C<Locale::MakeText>
+
+Upgraded from version 1.12 to 1.13.
+
+=item C<Log::Message>
+
+Upgraded from version 0.01 to 0.02.
+
+=item C<Math::BigFloat>
+
+Upgraded from version 1.59 to 1.60.
+
+=item C<Math::BigInt>
+
+Upgraded from version 1.88 to 1.89.
+
+=item C<Math::BigInt::FastCalc>
+
+Upgraded from version 0.16 to 0.19.
+
+=item C<Math::BigRat>
+
+Upgraded from version 0.21 to 0.22.
+
+=item C<Math::Complex>
+
+Upgraded from version 1.37 to 1.56.
+
+=item C<Math::Trig>
+
+Upgraded from version 1.04 to 1.20.
+
+=item C<Memoize>
+
+Upgraded from version 1.01_02 to 1.01_03 (just a minor documentation
+change).
+
+=item C<Module::Build>
+
+Upgraded from version 0.2808_01 to 0.34_02.
+
+=item C<Module::CoreList>
+
+Upgraded from version 2.13 to 2.18. This release no longer contains the
+C<%Module::CoreList::patchlevel> hash.
+
+=item C<Module::Load>
+
+Upgraded from version 0.12 to 0.16.
+
+=item C<Module::Load::Conditional>
+
+Upgraded from version 0.22 to 0.30.
+
+=item C<Module::Loaded>
+
+Upgraded from version 0.01 to 0.02.
+
+=item C<Module::Pluggable>
+
+Upgraded from version 3.6 to 3.9.
+
+=item C<NDBM_File>
+
+Upgraded from version 1.07 to 1.08.
+
+=item C<Net::Ping>
+
+Upgraded from version 2.33 to 2.36.
+
+=item C<NEXT>
+
+Upgraded from version 0.60_01 to 0.64.
+
+=item C<Object::Accessor>
+
+Upgraded from version 0.32 to 0.34.
+
+=item C<OS2::REXX>
+
+Upgraded from version 1.03 to 1.04.
+
+=item C<Package::Constants>
+
+Upgraded from version 0.01 to 0.02.
+
+=item C<PerlIO>
+
+Upgraded from version 1.04 to 1.06.
+
+=item C<PerlIO::via>
+
+Upgraded from version 0.04 to 0.07.
+
+=item C<Pod::Man>
+
+Upgraded from version 2.16 to 2.22.
+
+=item C<Pod::Parser>
+
+Upgraded from version 1.35 to 1.37.
+
+=item Pod::Perldoc
+
+Upgrade from version 3.14_02 to 3.15.
+
+=item C<Pod::Simple>
+
+Upgraded from version 3.05 to 3.07.
+
+=item C<Pod::Text>
+
+Upgraded from version 3.08 to 3.13.
+
+=item C<POSIX>
+
+Upgraded from version 1.13 to 1.17.
+
+=item C<Safe>
+
+Upgraded from 2.12 to 2.18.
+
+=item C<Scalar::Util>
+
+Upgraded from version 1.19 to 1.21.
+
+=item C<SelectSaver>
+
+Upgraded from 1.01 to 1.02.
+
+=item C<SelfLoader>
+
+Upgraded from 1.11 to 1.17.
+
+=item C<Socket>
+
+Upgraded from 1.80 to 1.82.
+
+=item C<Storable>
+
+Upgraded from 2.18 to 2.20.
+
+=item C<Switch>
+
+Upgraded from version 2.13 to 2.14. Please see L</Deprecations>.
+
+=item C<Symbol>
+
+Upgraded from version 1.06 to 1.07.
+
+=item C<Sys::Syslog>
+
+Upgraded from version 0.22 to 0.27.
+
+=item C<Term::ANSIColor>
+
+Upgraded from version 1.12 to 2.01.
+
+=item C<Term::ReadLine>
+
+Upgraded from version 1.03 to 1.04.
+
+=item C<Term::UI>
+
+Upgraded from version 0.18 to 0.20.
+
+=item C<Test::Harness>
+
+Upgraded from version 2.64 to 3.17.
+
+Note that one side-effect of the 2.x to 3.x upgrade is that the
+experimental C<Test::Harness::Straps> module (and its supporting
+C<Assert>, C<Iterator>, C<Point> and C<Results> modules) have been
+removed. If you still need this, then they are available in the
+(unmaintained) C<Test-Harness-Straps> distribution on CPAN.
+
+=item C<Test::Simple>
+
+Upgraded from version 0.72 to 0.92.
+
+=item C<Text::ParseWords>
+
+Upgraded from version 3.26 to 3.27.
+
+=item C<Text::Tabs>
+
+Upgraded from version 2007.1117 to 2009.0305.
+
+=item C<Text::Wrap>
+
+Upgraded from version 2006.1117 to 2009.0305.
+
+=item C<Thread::Queue>
+
+Upgraded from version 2.00 to 2.11.
+
+=item C<Thread::Semaphore>
+
+Upgraded from version 2.01 to 2.09.
+
+=item C<threads>
+
+Upgraded from version 1.67 to 1.73.
+
+=item C<threads::shared>
+
+Upgraded from version 1.14 to 1.29.
+
+=item C<Tie::RefHash>
+
+Upgraded from version 1.37 to 1.38.
+
+=item C<Tie::StdHandle>
+
+This has documentation changes, and has been assigned a version for the
+first time: version 4.2.
+
+=item C<Time::HiRes>
+
+Upgraded from version 1.9711 to 1.9719.
+
+=item C<Time::Local>
+
+Upgraded from version 1.18 to 1.1901.
+
+=item C<Time::Piece>
+
+Upgraded from version 1.12 to 1.15.
+
+=item C<Unicode::Normalize>
+
+Upgraded from version 1.02 to 1.03.
+
+=item C<Unicode::UCD>
+
+Upgraded from version 0.25 to 0.27.
+
+C<charinfo()> now works on Unified CJK code points added to later versions
+of Unicode.
+
+C<casefold()> has new fields returned to provide both a simpler interface
+and previously missing information. The old fields are retained for
+backwards compatibility. Information about Turkic-specific code points is
+now returned.
+
+The documentation has been corrected and expanded.
+
+=item C<UNIVERSAL>
+
+Upgraded from version 1.04 to 1.05.
+
+UNIVERSAL->import() is now deprecated.
+
+=item C<Win32>
+
+Upgraded from version 0.34 to 0.39.
+
+=item C<Win32API::File>
+
+Upgraded from version 0.1001_01 to 0.1101.
+
+=item C<XSLoader>
+
+Upgraded from version 0.08 to 0.10.
+
+=back
+
+=head1 Utility Changes
+
+=over 4
+
+=item F<h2ph>
+
+Now looks in C<include-fixed> too, which is a recent addition to gcc's
+search path.
+
+=item F<h2xs>
+
+No longer incorrectly treats enum values like macros (Daniel Burr).
+
+Now handles C++ style constants (C<//>) properly in enums. (A patch from
+Rainer Weikusat was used; Daniel Burr also proposed a similar fix).
+
+=item F<perl5db.pl>
+
+C<LVALUE> subroutines now work under the debugger.
+
+The debugger now correctly handles proxy constant subroutines, and
+subroutine stubs.
+
+=item F<perlbug>
+
+F<perlbug> now uses C<%Module::CoreList::bug_tracker> to print out upstream bug
+tracker URLs.
+
+Where the user names a module that their bug report is about, and we know the
+URL for its upstream bug tracker, provide a message to the user explaining
+that the core copies the CPAN version directly, and provide the URL for
+reporting the bug directly to upstream.
+
+=item F<perlthanks>
+
+Perl 5.11.0 added a new utility F<perlthanks>, which is a variant of
+F<perlbug>, but for sending non-bug-reports to the authors and maintainers
+of Perl. Getting nothing but bug reports can become a bit demoralising:
+we'll see if this changes things.
+
+=back
+
+=head1 New Documentation
+
+=over 4
+
+=item L<perlhaiku>
+
+This contains instructions on how to build perl for the Haiku platform.
+
+=item L<perlmroapi>
+
+This describes the new interface for pluggable Method Resolution Orders.
+
+=item L<perlperf>
+
+This document, by Richard Foley, provides an introduction to the use of
+performance and optimization techniques which can be used with particular
+reference to perl programs.
+
+=item L<perlrepository>
+
+This describes how to access the perl source using the I<git> version
+control system.
+
+=item L<perlthanks>
+
+This describes the new F<perlthanks> utility.
+
+=back
+
+=head1 Changes to Existing Documentation
+
+The various large F<Changes*> files (which listed every change made to perl
+over the last 18 years) have been removed, and replaced by a small file,
+also called F<Changes>, which just explains how that same information may
+be extracted from the git version control system.
+
+The file F<Porting/patching.pod> has been deleted, as it mainly described
+interacting with the old Perforce-based repository, which is now obsolete.
+Information still relevant has been moved to L<perlrepository>.
+
+L<perlapi>, L<perlintern>, L<perlmodlib> and L<perltoc> are now all
+generated at build time, rather than being shipped as part of the release.
+
+=head2 Documented -X overloading.
+
+=head2 Documented that when() treats specially most of the filetest operators
+
+=head2 Documented that DESTROY is subject to AUTOLOAD, and the related optimisations.
+
+=head2 Documented when as a syntax modifier
+
+=head2 Eliminated "Old Perl threads tutorial", which describes 5005 threads.
+
+pod/perlthrtut.pod is the same material reworked for ithreads.
+
+=head2 Removed a link to the attrs pragma, which has now been removed.
+
+=head2 update PERL_MEM_LOG in perlhack.pod
+
+=head2 Correct previous documentation: v-strings are not deprecated
+
+With version objects, we need them to use MODULE VERSION syntax. This
+patch removes the deprecation note.
+
+=head1 Performance Enhancements
+
+=over 4
+
+=item *
+
+A new internal cache means that C<isa()> will often be faster.
+
+=item *
+
+The implementation of C<C3> Method Resolution Order has been optimised -
+linearisation for classes with single inheritance is 40% faster. Performance
+for multiple inheritance is unchanged.
+
+=item *
+
+Under C<use locale>, the locale-relevant information is now cached on
+read-only values, such as the list returned by C<keys %hash>. This makes
+operations such as C<sort keys %hash> in the scope of C<use locale> much
+faster.
+
+=item *
+
+Empty C<DESTROY> methods are no longer called.
+
+=item *
+
+Faster sv_utf8_upgrade()
+
+=item *
+
+Speed up keys() on empty hash
+
+=back
+
+=head1 Installation and Configuration Improvements
+
+=head2 F<ext/> reorganisation
+
+The layout of directories in F<ext> has been revised. Specifically, all
+extensions are now flat, and at the top level, with C</> in pathnames
+replaced by C<->, so that F<ext/Data/Dumper/> is now F<ext/Data-Dumper/>,
+etc. The names of the extensions as specified to F<Configure>, and as
+reported by C<%Config::Config> under the keys C<dynamic_ext>,
+C<known_extensions>, C<nonxs_ext> and C<static_ext> have not changed, and
+still use C</>. Hence this change will not have any affect once perl is
+installed. However, C<Attribute::Handlers>, C<Safe> and C<mro> have now
+become extensions in their own right, so if you run F<Configure> with
+options to specify an exact list of extensions to build, you will need to
+change it to account for this.
+
+For 5.11.1, it is planned that many dual-life modules will have been moved
+from F<lib> to F<ext>; again this will have no effect on an installed
+perl, but will matter if you invoke F<Configure> with a pre-canned list of
+extensions to build.
+
+=head2 Configuration improvements
+
+If C<vendorlib> and C<vendorarch> are the same, then they are only added to
+C<@INC> once.
+
+C<$Config{usedevel}> and the C-level C<PERL_USE_DEVEL> are now defined if
+perl is built with C<-Dusedevel>.
+
+F<Configure> will enable use of C<-fstack-protector>, to provide protection
+against stack-smashing attacks, if the compiler supports it.
+
+F<Configure> will now determine the correct prototypes for re-entrant
+functions, and for C<gconvert>, if you are using a C++ compiler rather
+than a C compiler.
+
+On Unix, if you build from a tree containing a git repository, the
+configuration process will note the commit hash you have checked out, for
+display in the output of C<perl -v> and C<perl -V>. Unpushed local commits
+are automatically added to the list of local patches displayed by
+C<perl -V>.
+
+=head2 Compilation improvements
+
+As part of the flattening of F<ext>, all extensions on all platforms are
+built by F<make_ext.pl>. This replaces the Unix-specific
+F<ext/util/make_ext>, VMS-specific F<make_ext.com> and Win32-specific
+F<win32/buildext.pl>.
+
+=head2 Platform Specific Changes
+
+=over 4
+
+=item AIX
+
+Removed F<libbsd> for AIX 5L and 6.1. Only flock() was used from F<libbsd>.
+
+Removed F<libgdbm> for AIX 5L and 6.1. The F<libgdbm> is delivered as an
+optional package with the AIX Toolbox. Unfortunately the 64 bit version
+is broken.
+
+Hints changes mean that AIX 4.2 should work again.
+
+=item Cygwin
+
+On Cygwin we now strip the last number from the DLL. This has been the
+behaviour in the cygwin.com build for years. The hints files have been
+updated.
+
+=item DomainOS
+
+Support for Apollo DomainOS was removed in Perl 5.11.0
+
+=item FreeBSD
+
+The hints files now identify the correct threading libraries on FreeBSD 7
+and later.
+
+=item Irix
+
+We now work around a bizarre preprocessor bug in the Irix 6.5 compiler:
+C<cc -E -> unfortunately goes into K&R mode, but C<cc -E file.c> doesn't.
+
+=item Haiku
+
+Patches from the Haiku maintainers have been merged in. Perl should now
+build on Haiku.
+
+=item MiNT
+
+Support for Atari MiNT was removed in Perl 5.11.0.
+
+=item MirOS BSD
+
+Perl should now build on MirOS BSD.
+
+=item NetBSD
+
+Hints now supports versions 5.*.
+
+=item Stratus VOS
+
+Various changes from Stratus have been merged in.
+
+=item Symbian
+
+There is now support for Symbian S60 3.2 SDK and S60 5.0 SDK.
+
+=item Win32
+
+Improved message window handling means that C<alarm> and C<kill> messages
+will no longer be dropped under race conditions.
+
+=item VMS
+
+Reads from the in-memory temporary files of C<PerlIO::scalar> used to fail
+if C<$/> was set to a numeric reference (to indicate record-style reads).
+This is now fixed.
+
+VMS now supports C<getgrgid>.
+
+Many improvements and cleanups have been made to the VMS file name handling
+and conversion code.
+
+Enabling the C<PERL_VMS_POSIX_EXIT> logical name now encodes a POSIX exit
+status in a VMS condition value for better interaction with GNV's bash
+shell and other utilities that depend on POSIX exit values. See
+L<perlvms/"$?"> for details.
+
+C<File::Copy> now detects Unix compatibility mode on VMS.
+
+=back
+
+=head1 Selected Bug Fixes
+
+=over 4
+
+=item *
+
+C<-I> on shebang line now adds directories in front of @INC.
+as documented, and as does C<-I> when specified on the command-line.
+(Renée Bäcker)
+
+=item *
+
+C<kill> is now fatal when called on non-numeric process identifiers.
+Previously, an 'undef' process identifier would be interpreted as a request to
+kill process "0", which would terminate the current process group on POSIX
+systems. Since process identifiers are always integers, killing a non-numeric
+process is now fatal.
+
+=item *
+
+5.10.0 inadvertently disabled an optimisation, which caused a measurable
+performance drop in list assignment, such as is often used to assign
+function parameters from C<@_>. The optimisation has been re-instated, and
+the performance regression fixed.
+
+=item *
+
+Fixed memory leak on C<while (1) { map 1, 1 }> [RT #53038].
+
+=item *
+
+Some potential coredumps in PerlIO fixed [RT #57322,54828].
+
+=item *
+
+The debugger now works with lvalue subroutines.
+
+=item *
+
+The debugger's C<m> command was broken on modules that defined constants
+[RT #61222].
+
+=item *
+
+C<crypt()> and string complement could return tainted values for untainted
+arguments [RT #59998].
+
+=item *
+
+The C<-i>I<.suffix> command-line switch now recreates the file using
+restricted permissions, before changing its mode to match the original
+file. This eliminates a potential race condition [RT #60904].
+
+=item *
+
+On some UNIX systems, the value in C<$?> would not have the top bit set
+(C<$? & 128>) even if the child core dumped.
+
+=item *
+
+Under some circumstances, C<$^R> could incorrectly become undefined
+[RT #57042].
+
+=item *
+
+(XS) In various hash functions, passing a pre-computed hash to when the
+key is UTF-8 might result in an incorrect lookup.
+
+=item *
+
+(XS) Including F<XSUB.h> before F<perl.h> gave a compile-time error
+[RT #57176].
+
+=item *
+
+C<< $object->isa('Foo') >> would report false if the package C<Foo> didn't
+exist, even if the object's C<@ISA> contained C<Foo>.
+
+=item *
+
+Various bugs in the new-to 5.10.0 mro code, triggered by manipulating
+C<@ISA>, have been found and fixed.
+
+=item *
+
+Bitwise operations on references could crash the interpreter, e.g.
+C<$x=\$y; $x |= "foo"> [RT #54956].
+
+=item *
+
+Patterns including alternation might be sensitive to the internal UTF-8
+representation, e.g.
+
+ my $byte = chr(192);
+ my $utf8 = chr(192); utf8::upgrade($utf8);
+ $utf8 =~ /$byte|X}/i; # failed in 5.10.0
+
+=item *
+
+Within UTF8-encoded Perl source files (i.e. where C<use utf8> is in
+effect), double-quoted literal strings could be corrupted where a C<\xNN>,
+C<\0NNN> or C<\N{}> is followed by a literal character with ordinal value
+greater than 255 [RT #59908].
+
+=item *
+
+C<B::Deparse> failed to correctly deparse various constructs:
+C<readpipe STRING> [RT #62428], C<CORE::require(STRING)> [RT #62488],
+C<sub foo(_)> [RT #62484].
+
+=item *
+
+Using C<setpgrp()> with no arguments could corrupt the perl stack.
+
+=item *
+
+The block form of C<eval> is now specifically trappable by C<Safe> and
+C<ops>. Previously it was erroneously treated like string C<eval>.
+
+=item *
+
+In 5.10.0, the two characters C<[~> were sometimes parsed as the smart
+match operator (C<~~>) [RT #63854].
+
+=item *
+
+In 5.10.0, the C<*> quantifier in patterns was sometimes treated as
+C<{0,32767}> [RT #60034, #60464]. For example, this match would fail:
+
+ ("ab" x 32768) =~ /^(ab)*$/
+
+=item *
+
+C<shmget> was limited to a 32 bit segment size on a 64 bit OS [RT #63924].
+
+=item *
+
+Using C<next> or C<last> to exit a C<given> block no longer produces a
+spurious warning like the following:
+
+ Exiting given via last at foo.pl line 123
+
+=item *
+
+On Windows, C<'.\foo'> and C<'..\foo'> were treated differently than
+C<'./foo'> and C<'../foo'> by C<do> and C<require> [RT #63492].
+
+=item *
+
+Assigning a format to a glob could corrupt the format; e.g.:
+
+ *bar=*foo{FORMAT}; # foo format now bad
+
+=item *
+
+Attempting to coerce a typeglob to a string or number could cause an
+assertion failure. The correct error message is now generated,
+C<Can't coerce GLOB to I<$type>>.
+
+=item *
+
+Under C<use filetest 'access'>, C<-x> was using the wrong access mode. This
+has been fixed [RT #49003].
+
+=item *
+
+C<length> on a tied scalar that returned a Unicode value would not be
+correct the first time. This has been fixed.
+
+=item *
+
+Using an array C<tie> inside in array C<tie> could SEGV. This has been
+fixed. [RT #51636]
+
+=item *
+
+A race condition inside C<PerlIOStdio_close()> has been identified and
+fixed. This used to cause various threading issues, including SEGVs.
+
+=item *
+
+In C<unpack>, the use of C<()> groups in scalar context was internally
+placing a list on the interpreter's stack, which manifested in various
+ways, including SEGVs. This is now fixed [RT #50256].
+
+=item *
+
+Magic was called twice in C<substr>, C<\&$x>, C<tie $x, $m> and C<chop>.
+These have all been fixed.
+
+=item *
+
+A 5.10.0 optimisation to clear the temporary stack within the implicit
+loop of C<s///ge> has been reverted, as it turned out to be the cause of
+obscure bugs in seemingly unrelated parts of the interpreter [commit
+ef0d4e17921ee3de].
+
+=item *
+
+The line numbers for warnings inside C<elsif> are now correct.
+
+=item *
+
+The C<..> operator now works correctly with ranges whose ends are at or
+close to the values of the smallest and largest integers.
+
+=item *
+
+C<binmode STDIN, ':raw'> could lead to segmentation faults on some platforms.
+This has been fixed [RT #54828].
+
+=item *
+
+An off-by-one error meant that C<index $str, ...> was effectively being
+executed as C<index "$str\0", ...>. This has been fixed [RT #53746].
+
+=item *
+
+Various leaks associated with named captures in regexes have been fixed
+[RT #57024].
+
+=item *
+
+A weak reference to a hash would leak. This was affecting C<DBI>
+[RT #56908].
+
+=item *
+
+Using (?|) in a regex could cause a segfault [RT #59734].
+
+=item *
+
+Use of a UTF-8 C<tr//> within a closure could cause a segfault [RT #61520].
+
+=item *
+
+Calling C<sv_chop()> or otherwise upgrading an SV could result in an
+unaligned 64-bit access on the SPARC architecture [RT #60574].
+
+=item *
+
+In the 5.10.0 release, C<inc_version_list> would incorrectly list
+C<5.10.*> after C<5.8.*>; this affected the C<@INC> search order
+[RT #67628].
+
+=item *
+
+In 5.10.0, C<pack "a*", $tainted_value> returned a non-tainted value
+[RT #52552].
+
+=item *
+
+In 5.10.0, C<printf> and C<sprintf> could produce the fatal error
+C<panic: utf8_mg_pos_cache_update> when printing UTF-8 strings
+[RT #62666].
+
+=item *
+
+In the 5.10.0 release, a dynamically created C<AUTOLOAD> method might be
+missed (method cache issue) [RT #60220,60232].
+
+=item *
+
+In the 5.10.0 release, a combination of C<use feature> and C<//ee> could
+cause a memory leak [RT #63110].
+
+=item *
+
+C<-C> on the shebang (C<#!>) line is once more permitted if it is also
+specified on the command line. C<-C> on the shebang line used to be a
+silent no-op I<if> it was not also on the command line, so perl 5.10.0
+disallowed it, which broke some scripts. Now perl checks whether it is
+also on the command line and only dies if it is not [RT #67880].
+
+=item *
+
+In 5.10.0, certain types of re-entrant regular expression could crash,
+or cause the following assertion failure [RT #60508]:
+
+ Assertion rx->sublen >= (s - rx->subbeg) + i failed
+
+=back
+
+=head1 New or Changed Diagnostics
+
+=over 4
+
+=item C<panic: sv_chop %s>
+
+This new fatal error occurs when the C routine C<Perl_sv_chop()> was
+passed a position that is not within the scalar's string buffer. This
+could be caused by buggy XS code, and at this point recovery is not
+possible.
+
+=item C<Can't locate package %s for the parents of %s>
+
+This warning has been removed. In general, it only got produced in
+conjunction with other warnings, and removing it allowed an ISA lookup
+optimisation to be added.
+
+=item C<v-string in use/require is non-portable>
+
+This warning has been removed.
+
+=item C<Deep recursion on subroutine "%s">
+
+It is now possible to change the depth threshold for this warning from the
+default of 100, by recompiling the F<perl> binary, setting the C
+pre-processor macro C<PERL_SUB_DEPTH_WARN> to the desired value.
+
+=back
+
+=head1 Changed Internals
+
+=over 4
+
+=item *
+
+The J.R.R. Tolkien quotes at the head of C source file have been checked and
+proper citations added, thanks to a patch from Tom Christiansen.
+
+=item *
+
+C<vcroak()> now accepts a null first argument. In addition, a full audit
+was made of the "not NULL" compiler annotations, and those for several
+other internal functions were corrected.
+
+=item *
+
+New macros C<dSAVEDERRNO>, C<dSAVE_ERRNO>, C<SAVE_ERRNO>, C<RESTORE_ERRNO>
+have been added to formalise the temporary saving of the C<errno>
+variable.
+
+=item *
+
+The function C<Perl_sv_insert_flags> has been added to augment
+C<Perl_sv_insert>.
+
+=item *
+
+The function C<Perl_newSV_type(type)> has been added, equivalent to
+C<Perl_newSV()> followed by C<Perl_sv_upgrade(type)>.
+
+=item *
+
+The function C<Perl_newSVpvn_flags()> has been added, equivalent to
+C<Perl_newSVpvn()> and then performing the action relevant to the flag.
+
+Two flag bits are currently supported.
+
+=over 4
+
+=item C<SVf_UTF8>
+
+This will call C<SvUTF8_on()> for you. (Note that this does not convert an
+sequence of ISO 8859-1 characters to UTF-8). A wrapper, C<newSVpvn_utf8()>
+is available for this.
+
+=item C<SVs_TEMP>
+
+Call C<sv_2mortal()> on the new SV.
+
+=back
+
+There is also a wrapper that takes constant strings, C<newSVpvs_flags()>.
+
+=item *
+
+The function C<Perl_croak_xs_usage> has been added as a wrapper to
+C<Perl_croak>.
+
+=item *
+
+The functions C<PerlIO_find_layer> and C<PerlIO_list_alloc> are now
+exported.
+
+=item *
+
+C<PL_na> has been exterminated from the core code, replaced by local STRLEN
+temporaries, or C<*_nolen()> calls. Either approach is faster than C<PL_na>,
+which is a pointer deference into the interpreter structure under ithreads,
+and a global variable otherwise.
+
+=item *
+
+C<Perl_mg_free()> used to leave freed memory accessible via SvMAGIC() on
+the scalar. It now updates the linked list to remove each piece of magic
+as it is freed.
+
+=item *
+
+Under ithreads, the regex in C<PL_reg_curpm> is now reference counted. This
+eliminates a lot of hackish workarounds to cope with it not being reference
+counted.
+
+=item *
+
+C<Perl_mg_magical()> would sometimes incorrectly turn on C<SvRMAGICAL()>.
+This has been fixed.
+
+=item *
+
+The I<public> IV and NV flags are now not set if the string value has
+trailing "garbage". This behaviour is consistent with not setting the
+public IV or NV flags if the value is out of range for the type.
+
+=item *
+
+SV allocation tracing has been added to the diagnostics enabled by C<-Dm>.
+The tracing can alternatively output via the C<PERL_MEM_LOG> mechanism, if
+that was enabled when the F<perl> binary was compiled.
+
+=item *
-=head1 DESCRIPTION
+Uses of C<Nullav>, C<Nullcv>, C<Nullhv>, C<Nullop>, C<Nullsv> etc have been
+replaced by C<NULL> in the core code, and non-dual-life modules, as C<NULL>
+is clearer to those unfamiliar with the core code.
-This document describes differences between the 5.10.0 and the 5.11.0
-developement releases.
+=item *
-=head1 Incompatible Changes
+A macro C<MUTABLE_PTR(p)> has been added, which on (non-pedantic) gcc will
+not cast away C<const>, returning a C<void *>. Macros C<MUTABLE_SV(av)>,
+C<MUTABLE_SV(cv)> etc build on this, casting to C<AV *> etc without
+casting away C<const>. This allows proper compile-time auditing of
+C<const> correctness in the core, and helped picked up some errors (now
+fixed).
-=head1 Core Enhancements
+=item *
-=head1 The C<overloading> pragma
+Macros C<mPUSHs()> and C<mXPUSHs()> have been added, for pushing SVs on the
+stack and mortalizing them.
-This pragma allows you to lexically disable or enable overloading
-for some or all operations. (Yuval Kogman)
+=item *
-=head1 Modules and Pragmata
+Use of the private structure C<mro_meta> has changed slightly. Nothing
+outside the core should be accessing this directly anyway.
-=head2 Pragmata Changes
+=item *
+
+A new tool, F<Porting/expand-macro.pl> has been added, that allows you
+to view how a C preprocessor macro would be expanded when compiled.
+This is handy when trying to decode the macro hell that is the perl
+guts.
+
+=back
+
+=head1 New Tests
+
+Many modules updated from CPAN incorporate new tests.
+
+Several tests that have the potential to hang forever if they fail now
+incorporate a "watchdog" functionality that will kill them after a timeout,
+which helps ensure that C<make test> and C<make test_harness> run to
+completion automatically. (Jerry Hedden).
+
+Some core-specific tests have been added:
=over 4
-=item C<overloading>
+=item t/comp/retainedlines.t
-See L</"The C<overloading> pragma"> above.
+Check that the debugger can retain source lines from C<eval>.
+
+=item t/io/perlio_fail.t
+
+Check that bad layers fail.
+
+=item t/io/perlio_leaks.t
+
+Check that PerlIO layers are not leaking.
+
+=item t/io/perlio_open.t
+
+Check that certain special forms of open work.
+
+=item t/io/perlio.t
+
+General PerlIO tests.
+
+=item t/io/pvbm.t
+
+Check that there is no unexpected interaction between the internal types
+C<PVBM> and C<PVGV>.
+
+=item t/mro/package_aliases.t
+
+Check that mro works properly in the presence of aliased packages.
+
+=item t/op/dbm.t
+
+Tests for C<dbmopen> and C<dbmclose>.
+
+=item t/op/index_thr.t
+
+Tests for the interaction of C<index> and threads.
+
+=item t/op/pat_thr.t
+
+Tests for the interaction of esoteric patterns and threads.
+
+=item t/op/qr_gc.t
+
+Test that C<qr> doesn't leak.
+
+=item t/op/reg_email_thr.t
+
+Tests for the interaction of regex recursion and threads.
+
+=item t/op/regexp_qr_embed_thr.t
+
+Tests for the interaction of patterns with embedded C<qr//> and threads.
+
+=item t/op/regexp_unicode_prop.t
+
+Tests for Unicode properties in regular expressions.
+
+=item t/op/regexp_unicode_prop_thr.t
+
+Tests for the interaction of Unicode properties and threads.
+
+=item t/op/reg_nc_tie.t
+
+Test the tied methods of C<Tie::Hash::NamedCapture>.
+
+=item t/op/reg_posixcc.t
+
+Check that POSIX character classes behave consistently.
+
+=item t/op/re.t
+
+Check that exportable C<re> functions in F<universal.c> work.
+
+=item t/op/setpgrpstack.t
+
+Check that C<setpgrp> works.
+
+=item t/op/substr_thr.t
+
+Tests for the interaction of C<substr> and threads.
+
+=item t/op/upgrade.t
+
+Check that upgrading and assigning scalars works.
+
+=item t/uni/lex_utf8.t
+
+Check that Unicode in the lexer works.
+
+=item t/uni/tie.t
+
+Check that Unicode and C<tie> work.
=back
-=head1 Utility Changes
+=head1 Known Problems
-=head1 Documentation
+This is a list of some significant unfixed bugs, which are regressions
+from either 5.10.0 or 5.8.x.
-=head1 Performance Enhancements
+=over 4
-=head1 Installation and Configuration Improvements
+=item *
-=head1 Selected Bug Fixes
+C<List::Util::first> misbehaves in the presence of a lexical C<$_>
+(typically introduced by C<my $_> or implicitly by C<given>). The variable
+which gets set for each iteration is the package variable C<$_>, not the
+lexical C<$_> [RT #67694].
+
+A similar issue may occur in other modules that provide functions which
+take a block as their first argument, like
+
+ foo { ... $_ ...} list
+
+=item *
+
+The C<charnames> pragma may generate a run-time error when a regex is
+interpolated [RT #56444]:
+
+ use charnames ':full';
+ my $r1 = qr/\N{THAI CHARACTER SARA I}/;
+ "foo" =~ $r1; # okay
+ "foo" =~ /$r1+/; # runtime error
+
+A workaround is to generate the character outside of the regex:
+
+ my $a = "\N{THAI CHARACTER SARA I}";
+ my $r1 = qr/$a/;
+
+=item *
+
+Some regexes may run much more slowly when run in a child thread compared
+with the thread the pattern was compiled into [RT #55600].
+
+=back
+
+=head1 Deprecations
+
+The following items are now deprecated.
=over 4
-=item C<-I> on shebang line now adds directories in front of @INC
+=item *
-as documented, and as does C<-I> when specified on the command-line.
-(Renée Bäcker)
+C<Switch> is buggy and should be avoided. From perl 5.11.0 onwards, it is
+intended that any use of the core version of this module will emit a
+warning, and that the module will eventually be removed from the core
+(probably in perl 5.14.0). See L<perlsyn/"Switch statements"> for its
+replacement.
+
+=item *
+
+C<suidperl> has been removed. It used to provide a mechanism to
+emulate setuid permission bits on systems that don't support it properly.
+
+=item *
+
+Deprecate assignment to $[
+
+=item *
+
+Remove attrs, which has been deprecated since 1999/10/02.
+
+=item *
+
+Deprecate use of the attribute :locked on subroutines.
+
+=item *
+
+Deprecate using "locked" with the attributes pragma.
+
+=item *
+
+Deprecate using "unique" with the attributes pragma.
+
+=item *
+
+warn if ++ or -- are unable to change the value because it's beyond the limit of representation
+
+This uses a new warnings category: "imprecision".
+
+=item *
+
+Make lc/uc/lcfirst/ucfirst warn when passed undef.
+
+=item *
+
+Show constant in "Useless use of a constant in void context"
+
+=item *
+
+Make the new warning report undef constants as undef
+
+=item *
+
+Add a new warning, "Prototype after '%s'"
+
+=item *
+
+Tweak the "Illegal character in prototype" warning so it's more precise when reporting illegal characters after _
+
+=item *
+
+Unintented interpolation of $\ in regex
+
+=item *
+
+Make overflow warnings in gmtime/localtime only occur when warnings are on
+
+=item *
+
+Improve mro merging error messages.
+
+They are now very similar to those produced by Algorithm::C3.
+
+=item *
+
+Amelioration of the error message "Unrecognized character %s in column %d"
+
+Changes the error message to "Unrecognized character %s; marked by <--
+HERE after %s<-- HERE near column %d". This should make it a little
+simpler to spot and correct the suspicious character.
+
+=item *
+
+Explicitely point to $. when it causes an uninitialized warning for ranges in scalar context
=back
-=head1 New or Changed Diagnostics
+=head1 Acknowledgements
-=head1 Changed Internals
+Some of the work in this release was funded by a TPF grant.
-=head1 Known Problems
+Nicholas Clark officially retired from maintenance pumpking duty at the
+end of 2008; however in reality he has put much effort in since then to
+help get 5.10.1 into a fit state to be released, including writing a
+considerable chunk of this perldelta.
+
+Steffen Mueller and David Golden in particular helped getting CPAN modules
+polished and synchronised with their in-core equivalents.
+
+Craig Berry was tireless in getting maint to run under VMS, no matter how
+many times we broke it for him.
+
+The other core committers contributed most of the changes, and applied most
+of the patches sent in by the hundreds of contributors listed in F<AUTHORS>.
-=head2 Platform Specific Problems
+Much of the work of categorizing changes in this perldelta file was contributed
+by the following porters using changelogger.bestpractical.com:
+
+Nicholas Clark, leon, shawn, alexm, rjbs, rafl, Pedro Melo, brunorc,
+anonymous, ☄, Tom Hukins, anonymous, Jesse, dagolden, Moritz Onken,
+Mark Fowler, chorny, anonymous, tmtm
+
+Finally, thanks to Larry Wall, without whom none of this would be
+necessary.
=head1 Reporting Bugs
If you find what you think is a bug, you might check the articles
recently posted to the comp.lang.perl.misc newsgroup and the perl
-bug database at http://bugs.perl.org/ . There may also be
+bug database at http://rt.perl.org/perlbug/ . There may also be
information at http://www.perl.org/ , the Perl Home Page.
If you believe you have an unreported bug, please run the B<perlbug>
output of C<perl -V>, will be sent off to perlbug@perl.org to be
analysed by the Perl porting team.
+If the bug you are reporting has security implications, which make it
+inappropriate to send to a publicly archived mailing list, then please send
+it to perl5-security-report@perl.org. This points to a closed subscription
+unarchived mailing list, which includes all the core committers, who be able
+to help assess the impact of issues, figure out a resolution, and help
+co-ordinate the release of patches to mitigate or fix the problem across all
+platforms on which Perl is supported. Please only use this address for
+security issues in the Perl core, not for modules independently
+distributed on CPAN.
+
=head1 SEE ALSO
-The F<Changes> file for exhaustive details on what changed.
+The F<Changes> file for an explanation of how to view exhaustive details
+on what changed.
The F<INSTALL> file for how to build Perl.
The F<Artistic> and F<Copying> files for copyright information.
=cut
+
+
+=head1 TODO
+
+The following changes are a filtered list of changes which weren't backported
+to 5.10.1. They were run through changelogger.bestpractical.com and triaged
+by a set of Perl 5 Porters. Changes to blead after 5945e41e have not yet
+been triaged or integrated.
+
+The following changes need to be
+
+1) deleted if they don't merit inclusion
+
+ OR
+
+2) lightly copyedited and integrated into the perldelta above. Unfortunately, many of our
+commit messages are somewhat terse and require a bit more help to turn into something readable
+
+
+
+
+=head1 API
+
+=head2 Move the reg_stringify logic to Perl_sv_2pv_flags
+
+=head2 mg_copy ought to take an I32
+
+=head2 Perl_store_cop_label() isn't meant to be part of the public API.
+
+=head2 Perl_gv_fetchmethod{,_autoload,_flags} are actually never* called with a non-NULL stash.
+So change the parameter to NN.
+
+
+=head2 Promote Perl_setdefout() to the public API.
+
+=head2 Add get_cvs() as a shortcut for STR_WITH_LEN() and Perl_get_cvn_flags()
+
+=head2 In Perl_newCONSTSUB(), sv should not be NULL.
+
+=head2 GvUNIQUE* have been defined as 0 since 2005/06/30 - high time to remove them.
+
+=head2 invert and rename PERL_MEM_LOG_STDERR to PERL_MEM_LOG_NOIMPL
+
+Most users who want PERL_MEM_LOG want the default implementation,
+give it to them. Users providing their own implementation can
+obtain current behavior by adding -DPERL_MEM_LOG_NOIMPL.
+Frankly, the average user probably wants _ENV by default too.
+
+=head2 simplify PERL_MEM_LOG
+
+This combines multiple environment variable reads into 1,
+where it looks for values like "2mst"
+-2 leading digits are atoi()d to get FD
+-m memory logging please
+-s sv logging also
+-t timestamp those please.
+
+Combining these reduces overhead such that it seemed
+worthwhile to drop all the ifdefs. TBD whether this works
+in the environment that drove the original tradeoffs.
+
+If it isnt enough, Id be tempted by a global static ptr,
+and on 1st use, is read, seen 0, a lock is taken, and getenvar
+run to populate it, unlocked, proceed. This would remove
+iterative overheads.
+
+=head2 Add a parameter "destructing" to Gv_AMupdate()
+
+This boolean parameter indicates if the function has been called
+to update the overload magic table while looking up the DESTROY
+method. In this case, it's probably best to avoid croaking if
+those tables could not be updated (for example due to a method
+that could not be loaded.)
+
+=head2 Modify the return value of Gv_AMupdate to indicate a compilation error
+
+This way we'll restore most of the performance on object desctruction
+lost by the previous commit
+
+
+=head2 local $SIG{FOO} = sub {...}; sets signal handler to SIG_DFL
+
+Re: [perl #60360] [PATCH] UPDATED: local $SIG{FOO} = sub {...}; sets signal handler to SIG_DFL
+Message-ID: <20081112234504.GI2062@tytlal.topaz.cx>
+
+Updated patch to retain source compatibility.
+
+Plus using the correct PERL_ARGS_ASSERT_SAVE_HELEM_FLAGS
+macro and running make regen.
+
+=head2 Respecting inc_version_list while processing PERL_VENDORLIB_STEM
+
+Respecting inc_version_list while processing PERL_VENDORLIB_STEM
+From: "Mandalemula, Rajesh" <Rajesh.Mandalemula@deshaw.com>
+
+=head2 Change PL_debug behaviour
+
+
+String eval lines are now saved whenever
+a subroutine is defined, even if the eval'd string has subsequent
+syntax errors. This allows the debugger to single step into these
+subroutines.
+
+
+=head2 Tied filehandles now have an additional method EOF which provides the EOF type
+
+=head2 Perl is now smarter about adding a -I dir to the beginning or end of @INC
+
+=head2 On scope end, delete localized array elements that should not exist anymore, so that the array recovers its previous length. Honour EXISTS and DELETE for tied arrays.
+
+=head2 When a glob is deleted, mark its sub as ANON.
+
+=head2 Require a space or a newline after a "#line XXX" directive
+
+=head2 Forbid using "foreach" as an attribute
+
+(like all other control flow statements)
+
+
+=head2 Unregister signal handlers before destroying my_perl
+
+If the signal handler runs after perl_destruct() has been called, it
+will get an invalid (or NULL) my_perl when it asks for the
+thread-specific interpreter struct. This patch resets the signal
+handler for any signal previously handled by PL_csighandlerp to SIG_DFL
+before calling perl_destruct().
+
+=head2 Perl_magic_clearsig() needs to remove magic, else delete $SIG{INT} returns undef
+
+Perl_magic_clearsig() needs to remove magic, else delete $SIG{INT} returns undef
+instead of the now-removed INT handler.
+
+=head2 [perl #66452] TMPDIR not honored when opening an anonymous temporary file
+
+[perl #66452] TMPDIR not honored when opening an anonymous temporary file
+
+=head2 The attached patch to perlio.c fixes the problem of errno getting set.
+
+While I am firmly in the school of "do not look at $! except immediately
+after a failure", I also agree that spuriously setting it is messy. But
+there is just no way of knowing where your errno might have been.
+
+The problem was that PerlIO_fast_gets() (and other nearby similar
+capability-checking PerlIO routines) set the errno (and it was being
+called a lot, from sv_gets()). I think setting the errno here was
+a mistake: checking for "can has FOO" should not set external state,
+such as the errno. The patch removes that errno trashing from all those
+routines.
+
+=head2 Trim all trailing / from "." in @INC when filling %INC
+
+This fixes bug #66942 : as a / was left in the directory name,
+$INC{"Foo.pm"} for a file loaded from the current directory
+was given the incorrect value "/Foo.pm".
+
+=head2 Don't enqueue pending signals during global destruction
+
+Global destruction is not signal-safe. PL_psig_pend may already
+be gone when the signal handler is called (with destruct_level > 0).
+NULL it before freeing it to prevent a race condition.
+
+=head2 Eliminate struct regexp_allocated and xpvio_allocated.
+
+Calculate memory allocation using regexp and XPVIO, and the offset of the first
+real structure member. This avoids tripping over alignment differences between
+X* and x*_allocated, because x*_allocated doesn't have a double in it.
+
+
+=head1 internals
+
+=head2 [perl #47047] Use of inherited AUTOLOAD for non-method is deprecated
+
+=head2 Remove the definitions of Null(), Nullch, Nullfp, Nullsv and PL_na when code is within the perl source tree
+
+=head2 Replace our assert-which-can-be-caught-by-eval with the real deal from the standard C library.
+
+=head2 Tweak Perl_sv_upgrade() so that references can upgrade to SVt_PV
+
+=head2 Eliminate prelen from struct regexp.
+
+=head2 Change Perl_av_iter_p() to return IV* rather than I32* (which means
+
+=head2 Reorder the external regexp flags to get RXf_PMf_STD_PMMOD into the
+
+lowest 4 bits (which saves a shift), and the "flags indicating special
+patterns" into contiguous bits. This makes everything a little tidier,
+and saves 88 bytes (woohoo!) of object file with -Os on x86 FreeBSD.
+
+
+=head2 Re-implement the SvOOK() hack to store the offset as a BER encoded number in the part of the PVX that is being released.
+(It will always
+fit, as chopping off 1 byte gives just enough space for recording a
+delta of up to 127). This allows SvOOK() to co-exist with SvIOK_on(),
+which means all the calls to SvOOK_off() [with the possibility of a
+call to sv_backoff()] in SvIOK_on() can be removed. This ought to make
+a lot of straight line code a little bit simpler.
+OOK()d scalars can now be SVt_PV, as the IVX isn't needed.
+
+=head2 Abolish wraplen from struct regexp. We're already storing it in SvCUR.
+
+=head2 Make Perl_pregcomp() use SvUTF8() of the pattern, rather than the flag bit in pmflags, to decide whether the pattern is UTF-8.
+
+=head2 Abolish RXf_UTF8. Store the UTF-8-ness of the pattern with SvUTF8().
+
+=head2 In struct regexp move the member paren_names to the IV union.
+
+=head2 Make REGEXP a type distinct from SV. (Much like AV, CV, GV, HV).
+
+=head2 Allow sv_setsv_flags() to copy SVt_REGEXP much like it copies SVt_FORMAT - the just string buffer.
+
+
+=head2 Correct a long-standing ithreads reference counting anonamly
+
+The reference count only needs "doubling" when the scalar is pushed onto
+PL_regex_padav for the second time.
+
+
+=head2 In PL_regexp_padav, store regexps via real references, rather than hiding them within IVs.
+
+We can do this now that they are real SV pointers.
+
+=head2 With regexps stored as real RVs, we can eliminate SvREPADTMP().
+
+=head2 REGEXPs are now stored directly in PL_regex_padav, rather than indirectly via RVs.
+
+=head2 Remove code that protected pp_qr against REGEXPs going away during global destruction whilst they were stored via true references in PL_regex_padav.
+
+=head2 Remove PM_GETRE_SAFE and PM_SETRE_SAFE as nothing uses them.
+
+=head2 Note the U8 sized space created by removing -P, and check that it is now an illegal command line flag.
+
+=head2 Pack the recycled pad offsets into an SV at PL_regex_pad[0].
+
+=head2 Re-order so that the !SvOK() case is last (which should be rare)
+
+=head2 Extend PUSHFORMAT() to take a second parameter to set retop, to save NULLing it and then reassigning.
+
+=head2 Split struct block_sub into struct block_sub and struct block_format.
+
+Split struct block_sub into struct block_sub and struct block_format.
+(CXt_SUB and CXt_FORMAT were using some comon members, but some members
+were only for one or the other.)
+
+=head2 Change the wantarray result from caller from IV to bool for the SCALAR/ARRAY case.
+
+This doesn't contradict the documentation, as there isn't any. Oops.
+
+
+=head2 Give G_VOID, G_SCALAR and G_ARRAY the same numeric values as OPf_WANT_VOID, OPf_WANT_SCALAR and OPf_WANT_LIST.
+
+
+=head2 Squeeze the context type down to 4 bits, and move the private flags to fit within the next 4 bits.
+
+
+=head2 In struct block change blku_type from U8 to U16, and the "spare" U8 to U16, with the lockstep changes in struct subst.
+Eliminate lval from
+struct block_sub, and instead store it in the U16 in struct block.
+
+
+=head2 In struct block_eval, eliminate old_in_eval and old_op_type by storing the data in blk_u16.
+
+
+=head2 The layout for struct block_loop under ithreads can be simplified.
+
+Instead of wedging the pad offset into a void* iterdata, and always
+storing PL_comppad even when it isn't used, instead do this:
+
+PAD *oldcomppad; /* Also used for the GV, if targoffset is 0 */
+/* This is also accesible via cx->blk_loop.my_op->op_targ */
+PADOFFSET targoffset;
+
+and store the GV pointer in oldcompad. Pointers to pointers seems
+cleaner. This also allows us to eliminate the flag bit CXp_PADVAR.
+
+
+=head2 In XS_PerlIO_get_layers() take advantage of the implementation of
+
+In XS_PerlIO_get_layers() take advantage of the implementation of
+PerlIO_get_layers(), by co-opting the new SVs it creates, rather than
+copying them.
+
+
+=head2 Micro-optimise the order of the context types. [Because I can :-)]
+
+=head2 [patch] optimize OP_IS_(FILETEST|SOCKET) macros
+
+=head2 Eliminate ck_lengthconst.
+
+=head2 Chainsaw DEBUG_S out, as suggested by Vincent Pit.
+
+=head2 Unsupported private API functions are now declared "static" to prevent leakage to the public API
+
+=head2 Perl_cv_ckproto() is not part of the public API, and not used anywhere. It has been removed
+
+=head2 Remove all the 5005threads specific mutex macros, which are now vestigial.
+
+=head2 Do not honor TMPDIR for anonymous temporary files when tainting
+
+Use a default of /tmp on Unixes when TMPDIR is unset or empty, or
+when creation of a temporary file in it fails
+
+=head2 Add a pluggable hook in op_free()
+
+
projects / p5sagit/p5-mst-13.2.git / blobdiff