=encoding utf8

=head1 NAME

perldelta - what is new for perl v5.25.4

=head1 DESCRIPTION

This document describes differences between the 5.25.3 release and the 5.25.4
release.

If you are upgrading from an earlier release such as 5.25.2, first read
L<perl5253delta>, which describes differences between 5.25.2 and 5.25.3.

=head1 Performance Enhancements

=over 4

=item *

The rather slow implementation for the experimental subroutine signatures
feature has been made much faster; it is now comparable in speed with the
old-style C<my ($a, $b, @c) = @_>.

=back

=head1 Documentation

=head2 Changes to Existing Documentation

=head3 L<perlcall>

=over 4

=item *

Removed redundant C<dSP> from an example.

=back

=head1 Modules and Pragmata

=head2 Updated Modules and Pragmata

=over 4

=item *

L<Archive::Tar> has been upgraded from version 2.08 to 2.10.

=item *

L<arybase> has been upgraded from version 0.11 to 0.12.

=item *

L<B> has been upgraded from version 1.62 to 1.63.

=item *

L<B::Concise> has been upgraded from version 0.996 to 0.998.

=item *

L<B::Deparse> has been upgraded from version 1.37 to 1.38.

=item *

L<base> has been upgraded from version 2.23 to 2.24.

=item *

L<bignum> has been upgraded from version 0.43 to 0.43_01.

=item *

L<Carp> has been upgraded from version 1.41 to 1.42.

=item *

L<Config::Perl::V> has been upgraded from version 0.26 to 0.27.

=item *

L<CPAN> has been upgraded from version 2.14 to 2.14_01.

=item *

L<CPAN::Meta> has been upgraded from version 2.150005 to 2.150010.

=item *

L<Digest> has been upgraded from version 1.17 to 1.17_01.

=item *

L<Digest::SHA> has been upgraded from version 5.95 to 5.96.

=item *

L<Encode> has been upgraded from version 2.84 to 2.86.

=item *

L<encoding> has been upgraded from version 2.17_01 to 2.18.

=item *

L<Errno> has been upgraded from version 1.25 to 1.26.

=item *

L<ExtUtils::MakeMaker> has been upgraded from version 7.18 to 7.24.

=item *

L<File::Fetch> has been upgraded from version 0.48 to 0.52.

=item *

L<File::Spec> has been upgraded from version 3.64 to 3.65.

=item *

L<Hash::Util> has been upgraded from version 0.20 to 0.21.

=item *

L<HTTP::Tiny> has been upgraded from version 0.058 to 0.064.

=item *

L<I18N::LangTags> has been upgraded from version 0.40 to 0.41.

=item *

L<IO> has been upgraded from version 1.36 to 1.37.

=item *

L<IO-Compress> has been upgraded from version 2.069 to 2.069_01.

=item *

L<IO::Socket::IP> has been upgraded from version 0.37 to 0.38.

=item *

L<IPC::Cmd> has been upgraded from version 0.94 to 0.96.

=item *

L<JSON::PP> has been upgraded from version 2.27400 to 2.27400_01.

=item *

L<Locale::Maketext> has been upgraded from version 1.27 to 1.28.

=item *

L<Locale::Maketext::Simple> has been upgraded from version 0.21 to 0.21_01.

=item *

L<Memoize> has been upgraded from version 1.03 to 1.03_01.

=item *

L<Module::CoreList> has been upgraded from version 5.20160720 to 5.20160820.

=item *

L<Module::Load::Conditional> has been upgraded from version 0.64 to 0.68.

=item *

L<Module::Metadata> has been upgraded from version 1.000032 to 1.000033.

=item *

L<Net::Ping> has been upgraded from version 2.43 to 2.44.

=item *

L<NEXT> has been upgraded from version 0.65 to 0.67.

=item *

L<Opcode> has been upgraded from version 1.35 to 1.37.

=item *

L<Pod::Html> has been upgraded from version 1.22 to 1.2201.

=item *

L<Pod::Perldoc> has been upgraded from version 3.25_02 to 3.27.

=item *

L<POSIX> has been upgraded from version 1.70 to 1.71.

=item *

L<Storable> has been upgraded from version 2.56 to 2.57.

=item *

L<Sys::Syslog> has been upgraded from version 0.34 to 0.34_01.

=item *

L<Test> has been upgraded from version 1.28 to 1.29.

=item *

L<Test::Harness> has been upgraded from version 3.36 to 3.36_01.

=item *

L<Test::Simple> has been upgraded from version 1.302045 to 1.302052.

=item *

L<Tie::Hash::NamedCapture> has been upgraded from version 0.09 to 0.10.

=item *

L<Time::Local> has been upgraded from version 1.2300 to 1.24.

=back

=head1 Configuration and Compilation

=over 4

=item *

A probe for C<gai_strerror> was added to F<Configure> that checks if the
the gai_strerror() routine is available and can be used to
translate error codes returned by getaddrinfo() into human
readable strings.

=back

=head1 Platform Support

=head2 Platform-Specific Notes

=over 4

=item Hurd

The hints for Hurd have been improved enabling malloc wrap and reporting the
GNU libc used (previously it was an empty string when reported).

=back

=head1 Internal Changes

=over 4

=item *

Three new ops, C<OP_ARGELEM>, C<OP_ARGDEFELEM> and C<OP_ARGCHECK> have
been added. These are intended principally to implement the individual
elements of a subroutine signature, plus any overall checking required.

=back

=head1 Selected Bug Fixes

=over 4

=item *

Problems with in-place array sorts: code like C<@a = sort { ... } @a>,
where the source and destination of the sort are the same plain array, are
optimised to do less copying around. Two side-effects of this optimisation
were that the contents of C<@a> as visible to to sort routine were
partially sorted, and under some circumstances accessing C<@a> during the
sort could crash the interpreter. Both these issues have been fixed, and
Sort functions see the original value of C<@a>.

=item *

Non-ASCII string delimiters are now reported correctly in error messages
for unterminated strings.  [perl #128701]

=item *

C<pack("p", ...)> used to emit its warning ("Attempt to pack pointer to
temporary value") erroneously in some cases, but has been fixed.

=item *

C<@DB::args> is now exempt from "used once" warnings.  The warnings only
occurred under B<-w>, because F<warnings.pm> itself uses C<@DB::args>
multiple times.

=item *

The use of built-in arrays or hash slices in a double-quoted string no
longer issues a warning ("Possible unintended interpolation...") if the
variable has not been mentioned before.  This affected code like
C<qq|@DB::args|> and C<qq|@SIG{'CHLD', 'HUP'}|>.  (The special variables
C<@-> and C<@+> were already exempt from the warning.)

=item *

C<gethostent> and similar functions now perform a null check internally, to
avoid crashing with torsocks.  This was a regression from 5.22.  [perl
#128740]

=item *

C<defined *{'!'}>, C<defined *{'['}>, and C<defined *{'-'}> no longer leak
memory if the typeglob in question has never been accessed before.

=item *

In 5.25.4 fchown() was changed not to accept negative one as an argument
because in some platforms that is an error.  However, in some other platforms
that is an acceptable argument.  This change has been reverted [perl #128967].

=item *

Mentioning the same constant twice in a row (which is a syntax error) no
longer fails an assertion under debugging builds.  This was a regression
from 5.20.  [perl #126482]

=item *

Many issues relating to C<printf "%a"> of hexadecimal floating point
were fixed.  In addition, the "subnormals" (formerly known as "denormals")
floating point anumbers are now supported both with the plain IEEE 754
floating point numbers (64-bit or 128-bit) and the x86 80-bit
"extended precision".  Note that subnormal hexadecimal floating
point literals will give a warning about "exponent underflow".
[perl #128843, #128889, #128890, #128893, #128909, #128919]

=item *

A regression in 5.24 with C<tr/\N{U+...}/foo/> when the code point was between
128 and 255 has been fixed. [perl #128734].

=item *

A regression from the previous development release, 5.23.3, where
compiling a regular expression could crash the interpreter has been
fixed. [perl #128686].

=item *

Use of a string delimiter whose code point is above 2**31 now works
correctly on platforms that allow this.  Previously, certain characters,
due to truncation, would be confused with other delimiter characters
with special meaning (such as C<?> in C<m?...?>), resulting
in inconsistent behaviour.  Note that this is non-portable,
and is based on Perl's extension to UTF-8, and is probably not
displayable nor enterable by any editor. [perl #128738]

=item *

C<@{x> followed by a newline where C<x> represents a control or non-ASCII
character no longer produces a garbled syntax error message or a crash.
[perl #128951]

=back

=head1 Acknowledgements

Perl 5.25.4 represents approximately 4 weeks of development since Perl 5.25.3
and contains approximately 18,000 lines of changes across 820 files from 23
authors.

Excluding auto-generated files, documentation and release tools, there were
approximately 9,200 lines of changes to 660 .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 5.25.4:

Chris 'BinGOs' Williams, Craig A. Berry, Dagfinn Ilmari Mannsåker, Dan
Collins, Daniel Dragan, David Mitchell, Father Chrysostomos, H.Merijn Brand,
James E Keenan, Jarkko Hietaniemi, Karen Etheridge, Karl Williamson, Lukas Mai,
Neil Bowers, Nicolas R., Pino Toscano, Rafael Garcia-Suarez, Richard Levitte,
Shlomi Fish, Smylers, Steve Hay, Tony Cook, Yves Orton.

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 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 see
L<perlsec/SECURITY VULNERABILITY CONTACT INFORMATION>
for details of how to report the issue.

=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
