=encoding utf8

=head1 NAME

perl5235delta - what is new for perl v5.23.5

=head1 DESCRIPTION

This document describes differences between the 5.23.4 release and the 5.23.5
release.

If you are upgrading from an earlier release such as 5.23.3, first read
L<perl5234delta>, which describes differences between 5.23.3 and 5.23.4.

=head1 Performance Enhancements

=over 4

=item *

Faster addition, subtraction and multiplication.

Since 5.8.0, arithmetic became slower due to the need to support
64-bit integers. To deal with 64-bit integers, a lot more corner
cases need to be checked, which adds time. We now detect common
cases where there is no need to check for those corner cases,
and special-case them.

=item *

Faster preincrement, predecrement, postincrement, postdecrement.

By internally splitting the functions which handled multiple
cases into different functions.

=back

=head1 Modules and Pragmata

=head2 Updated Modules and Pragmata

=over 4

=item *

L<arybase> has been upgraded from version 0.10 to 0.11.

=item *

L<B> has been upgraded from version 1.60 to 1.61.

=item *

L<base> has been upgraded from version 2.22 to 2.22_01.

Better handling of attempts to load non-existent modules. 
Improvements to fields.pm documentation. L<base> now requires v5.8.0.

=item *

L<Carp> has been upgraded from version 1.37 to 1.38.

Improvements when working with older perls.

=item *

L<Config::Perl::V> has been upgraded from version 0.24 to 0.25.

=item *

L<Devel::Peek> has been upgraded from version 1.22 to 1.23.

=item *

L<Dumpvalue> has been upgraded from version 1.17 to 1.18.

=item *

L<DynaLoader> has been upgraded from version 1.35 to 1.36.

=item *

L<fields> has been upgraded from version 2.17 to 2.22_01.

=item *

L<File::Find> has been upgraded from version 1.31 to 1.32.

Handles empty directory lists.

=item *

L<File::Spec> has been upgraded from version 3.58 to 3.59.

=item *

L<Getopt::Long> has been upgraded from version 2.47 to 2.48.

Fixes an issue with C<< gnu_compat >>

=item *

L<Hash::Util::FieldHash> has been upgraded from version 1.17 to 1.18.

=item *

L<IPC::Open3> has been upgraded from version 1.19 to 1.20.

Include the error message on C<< exec() >> failure.

=item *

L<Math::BigInt> has been upgraded from version 1.999704 to 1.999710.

=item *

L<Math::BigInt::FastCalc> has been upgraded from version 0.34 to 0.37.

=item *

L<Module::CoreList> has been upgraded from version 5.20151020 to 5.20151120.

=item *

L<Module::Metadata> has been upgraded from version 1.000029 to 1.000030.

Temp dirs cleaned up during tests. More accurately mark tests as TODO, so as to have a quieter and less confusing test run without passing TODO tests.

=item *

L<PerlIO::encoding> has been upgraded from version 0.22 to 0.23.

=item *

L<PerlIO::mmap> has been upgraded from version 0.014 to 0.015.

=item *

L<PerlIO::scalar> has been upgraded from version 0.23 to 0.24.

=item *

L<PerlIO::via> has been upgraded from version 0.15 to 0.16.

=item *

L<Pod::Simple> has been upgraded from version 3.30 to 3.32.

Switched debugging output from C<< STDOUT >> to C<< STDERR >>.

Added C<< errata_seen() >> to make POD errors easily accessible.

Simplified the detection of case-insensitivity in Pod::Simple::Search.

Fixed C<< Use of uninitialized value $1 in lc >> warning in
Pod::Simple::Search.

If C<< @INC >> includes the current directory symbol, C<.>, the
C<< survey() >> method of C<< Pod::Simple::Search >> no longer excludes
it from its list of directories to search. Instead, The C<< survey() >> and
C<< find() >> methods now both exclude duplicate directories from C<< @INC >>
(RT #102344).

Moved source repository and updated links to new perl-pod GitHub
organization: L<https://github.com/perl-pod/pod-simple>.

Improved repository links and added GitHub issue tracking link to
the distribution metadata.

Switched from C<< File::Spec >>'s C<< catdir >> to C<< catfile >>
for path names, to fix failures on VMS. Also now use Unix path semantics
where they're not required to be platform-specific. (RT #105511).

Improved the example use of the C<< html_encode_chars() >> method in
the C<< Pod::Simple::XHTML >> documentation.

=item *

L<POSIX> has been upgraded from version 1.58 to 1.59.

=item *

L<Thread::Queue> has been upgraded from version 3.06 to 3.07.

=item *

L<threads> has been upgraded from version 2.03 to 2.04.

=item *

L<threads::shared> has been upgraded from version 1.48 to 1.49.

=item *

L<Tie::Scalar> has been upgraded from version 1.03 to 1.04.

=item *

L<Time::HiRes> has been upgraded from version 1.9727_02 to 1.9728.

=item *

L<Time::Piece> has been upgraded from version 1.30 to 1.31.

=item *

L<Unicode::Normalize> has been upgraded from version 1.21 to 1.23.

=item *

L<XSLoader> has been upgraded from version 0.20 to 0.21.

=back

=head1 Diagnostics

The following additions or changes have been made to diagnostic output,
including warnings and fatal error messages.  For the complete list of
diagnostic messages, see L<perldiag>.

=head2 New Diagnostics

=head3 New Errors

=over 4

=item *

L<<< Sequence (?... not terminated in regex; marked by S<<-- HERE> in mE<sol>%sE<sol>|perldiag/"Sequence (?... not terminated in regex; marked by <-- HERE in mE<sol>%sE<sol>" >>>

=back

=head2 Changes to Existing Diagnostics

=over 4

=item *

When running out of memory during an attempt the increase the stack
size, previously, perl would die using the cryptic message 
C<< panic: av_extend_guts() negative count (-9223372036854775681) >>.
This has been fixed to show the prettier message:
L<< Out of memory during stack extend|perldiag/"Out of memory during %s extend" >>

=back

=head1 Configuration and Compilation

=over 4

=item *

C<Configure> now acts as if the C<-O> option is always passed, allowing command
line options to override saved configuration.  This should eliminate confusion
when command line options are ignored for no obvious reason.  C<-O> is now
permitted, but ignored.

=item *

Some filesystem stat symbols which were not used by the Perl core 
were removed in an earlier commit. However, since these symbols
turned out to be used by at least one CPAN module, these symbols
have been restored.

=item *

C<< PPPort.so/PPPort.dll >> no longer get installed, as they are
not used by C<< PPPort.pm >>, only by its test files.

=item *

It is now possible to specify which compilation date to show on
C<< perl -V >> output, by setting the macro C<< PERL_BUILD_DATE >>.

=back

=head1 Platform Support

=head2 Platform-Specific Notes

=over 4

=item Win32

Win32 does now a parallel build with C++.

=item Tru64

Workaround where Tru64 balks when prototypes are listed as
C<< PERL_STATIC_INLINE >>, but where the test is build with
C<< -DPERL_NO_INLINE_FUNCTIONS >>.

=back

=head1 Internal Changes

=over 4

=item *

C<< sv_ref() >> is now part of the API.

=back

=head1 Selected Bug Fixes

=over 4

=item *

C<\b{sb}> works much better.  In Perl v5.22.0, this new construct didn't
seem to give the expected results, yet passed all the tests in the
extensive suite furnished by Unicode.  It turns out that it was because
these were short input strings, and the failures had to do with longer
inputs.  This was fixed in Perl 5.23.4, but the improvement was not
noticed until after that was released, so is included here now.

=item *

Certain syntax errors in
L<perlrecharclass/Extended Bracketed Character Classes> caused panics
instead of the proper error message.  This has now been fixed. [perl
#126481]

=item *

An earlier commit added a message when a quantifier in a regular
expression was useless, but then caused the parser to skip it;
this caused the surplus quantifier to be silently ignored, instead
of throwing an error. This is now fixed. [perl #126253]

=item *

The switch to building non-XS modules last in win32/makefile.mk (introduced
by design as part of the changes to enable parallel building) caused the
build of POSIX to break due to problems with the version module. This
is now fixed.

=item *

Improved parsing of hex float constants.

=item *

Fixed an issue with C<< pack >> where C<< pack "H" >> (and C<< pack "h" >>)
could read past the source when given a non-utf8 source, and a utf8 target.
[perl #126325]

=item *

Fixed several cases where perl would abort due to a segmentation fault,
or a C-level assert. [perl #126615], [perl #126602], [perl #126193].

=back

=head1 Acknowledgements

Perl 5.23.5 represents approximately 4 weeks of development since Perl 5.23.4
and contains approximately 12,000 lines of changes across 290 files from 23
authors.

Excluding auto-generated files, documentation and release tools, there were
approximately 6,400 lines of changes to 180 .pm, .t, .c and .h files.

Perl continues to flourish into its third decade thanks to a vibrant community
of users and developers. The following people are known to have contributed the
improvements that became Perl 5.23.5:

Aaron Crane, Abigail, Chris 'BinGOs' Williams, Craig A. Berry, Dagfinn Ilmari
Mannsåker, Daniel Dragan, David Mitchell, Dr.Ruud, H.Merijn Brand, Ivan
Pozdeev, James E Keenan, Jarkko Hietaniemi, Jerry D. Hedden, Karen Etheridge,
Karl Williamson, Lukas Mai, Mohammed El-Afifi, Niko Tyni, Peter Rabbitson,
Reini Urban, Ricardo Signes, Steve Hay, Tony Cook.

The list above is almost certainly incomplete as it is automatically generated
from version control history. In particular, it does not include the names of
the (very much appreciated) contributors who reported issues to the Perl bug
tracker.

Many of the changes included in this version originated in the CPAN modules
included in Perl's core. We're grateful to the entire CPAN community for
helping Perl to flourish.

For a more complete list of all of Perl's historical contributors, please see
the F<AUTHORS> file in the Perl source distribution.

=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
L<https://rt.perl.org/> .  There may also be information at
L<http://www.perl.org/> , the Perl Home Page.

If you believe you have an unreported bug, please run the L<perlbug> program
included with your release.  Be sure to trim your bug down to a tiny but
sufficient test case.  Your bug report, along with the 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 will 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 an explanation of how to view exhaustive details on
what changed.

The F<INSTALL> file for how to build Perl.

The F<README> file for general stuff.

The F<Artistic> and F<Copying> files for copyright information.

=cut
