5 [ this is a template for a new perldelta file. Any text flagged as XXX needs
6 to be processed before release. ]
8 perldelta - what is new for perl v5.21.9
12 This document describes differences between the 5.21.8 release and the 5.21.9
15 If you are upgrading from an earlier release such as 5.21.7, first read
16 L<perl5218delta>, which describes differences between 5.21.7 and 5.21.8.
20 XXX Any important notices here
22 =head1 Core Enhancements
24 XXX New core language features go here. Summarize user-visible core language
25 enhancements. Particularly prominent performance optimisations could go
26 here, but most should go in the L</Performance Enhancements> section.
28 [ List each enhancement as a =head2 entry ]
32 XXX Any security-related notices go here. In particular, any security
33 vulnerabilities closed should be noted here rather than in the
34 L</Selected Bug Fixes> section.
36 [ List each security issue as a =head2 entry ]
38 =head1 Incompatible Changes
40 XXX For a release on a stable branch, this section aspires to be:
42 There are no changes intentionally incompatible with 5.XXX.XXX
43 If any exist, they are bugs, and we request that you submit a
44 report. See L</Reporting Bugs> below.
46 [ List each incompatible change as a =head2 entry ]
50 XXX Any deprecated features, syntax, modules etc. should be listed here.
52 =head2 Module removals
54 XXX Remove this section if inapplicable.
56 The following modules will be removed from the core distribution in a
57 future release, and will at that time need to be installed from CPAN.
58 Distributions on CPAN which require these modules will need to list them as
61 The core versions of these modules will now issue C<"deprecated">-category
62 warnings to alert you to this fact. To silence these deprecation warnings,
63 install the modules in question from CPAN.
65 Note that these are (with rare exceptions) fine modules that you are encouraged
66 to continue to use. Their disinclusion from core primarily hinges on their
67 necessity to bootstrapping a fully functional, CPAN-capable Perl installation,
68 not usually on concerns over their design.
74 XXX Note that deprecated modules should be listed here even if they are listed
75 as an updated module in the L</Modules and Pragmata> section.
79 [ List each other deprecation as a =head2 entry ]
81 =head1 Performance Enhancements
83 XXX Changes which enhance performance without changing behaviour go here.
84 There may well be none in a stable release.
86 [ List each enhancement as a =item entry ]
96 =head1 Modules and Pragmata
98 XXX All changes to installed files in F<cpan/>, F<dist/>, F<ext/> and F<lib/>
99 go here. If Module::CoreList is updated, generate an initial draft of the
100 following sections using F<Porting/corelist-perldelta.pl>. A paragraph summary
101 for important changes should then be added by hand. In an ideal world,
102 dual-life modules would have a F<Changes> file that could be cribbed.
104 [ Within each section, list entries as a =item entry ]
106 =head2 New Modules and Pragmata
116 =head2 Updated Modules and Pragmata
122 L<B> has been upgraded from version 1.55 to 1.56.
126 L<bigint>, L<bignum>, L<bigrat> have been upgraded to version 0.39.
128 Document in CAVEATS that using strings as numbers won't always invoke
129 the big number overloading, and how to invoke it. [perl #123064]
133 L<Devel::Peek> has been upgraded from version 1.21 to 1.22.
137 L<Encode> has been upgraded from version 2.67 to 2.68.
139 Building in C++ mode on Windows now works.
143 L<Errno> has been upgraded from version 1.22 to 1.23.
145 Add C<-P> to the preprocessor command-line on GCC 5. GCC added extra
146 line directives, breaking parsing of error code definitions. [perl
151 L<Opcode> has been upgraded from version 1.31 to 1.32.
155 L<PerlIO::scalar> has been upgraded from version 0.21 to 0.22.
157 Attempting to write at file positions impossible for the platform now
158 fail early rather than wrapping at 4GB.
162 L<Win32> has been upgraded from version 0.49 to 0.51.
164 GetOSName() now supports Windows 8.1, and building in C++ mode now works.
168 L<Win32API::File> has been upgraded from version 0.1201 to 0.1202
170 Building in C++ mode now works.
174 L<POSIX> has been upgraded from version 1.49 to 1.50.
178 L<Benchmark> has been upgraded from version 1.19 to 1.20.
182 L<Unicode::UCD> has been upgraded from version 0.60 to 0.61.
188 A new function L<property_values()|Unicode::UCD/prop_values()>
189 has been added to return a given property's possible values.
193 A new function L<charprop()|Unicode::UCD/charprop()>
194 has been added to return the value of a given property for a given code
199 A bug has been fixed so that L<propaliases()|Unicode::UCD/prop_aliases()>
200 returns the correct short and long names for the Perl extensions where
205 A bug has been fixed so that
206 L<prop_value_aliases()|Unicode::UCD/prop_value_aliases()>
207 returns C<undef> instead of a wrong result for properties that are Perl
212 This module now works on EBCDIC platforms.
218 =head2 Removed Modules and Pragmata
230 XXX Changes to files in F<pod/> go here. Consider grouping entries by
231 file and be sure to link to the appropriate page, e.g. L<perlfunc>.
233 =head2 New Documentation
235 XXX Changes which create B<new> files in F<pod/> go here.
239 XXX Description of the purpose of the new file here
241 =head2 Changes to Existing Documentation
243 XXX Changes which significantly change existing files in F<pod/> go here.
244 However, any changes to F<pod/perldiag.pod> should go in the L</Diagnostics>
253 XXX Description of the change here
263 L<perlfaq> has been synchronized with version 5.021009 from CPAN.
269 The following additions or changes have been made to diagnostic output,
270 including warnings and fatal error messages. For the complete list of
271 diagnostic messages, see L<perldiag>.
273 XXX New or changed warnings emitted by the core's C<C> code go here. Also
274 include any changes in L<perldiag> that reconcile it to the C<C> code.
276 =head2 New Diagnostics
278 XXX Newly added diagnostic messages go under here, separated into New Errors
287 XXX L<message|perldiag/"message">
297 XXX L<message|perldiag/"message">
301 =head2 Changes to Existing Diagnostics
303 XXX Changes (i.e. rewording) of diagnostic messages go here
309 XXX Describe change here
313 =head1 Utility Changes
315 XXX Changes to installed programs such as F<perlbug> and F<xsubpp> go here.
316 Most of these are built within the directory F<utils>.
318 [ List utility changes as a =head2 entry for each utility and =item
319 entries for each change
320 Use L<XXX> with program names to get proper documentation linking. ]
328 F<h2ph> now handles hexadecimal constants in the compiler's predefined
329 macro definitions, as visible in C<$Config{cppsymbols}>. [perl
334 =head1 Configuration and Compilation
336 XXX Changes to F<Configure>, F<installperl>, F<installman>, and analogous tools
337 go here. Any other changes to the Perl build process should be listed here.
338 However, any platform-specific changes should be listed in the
339 L</Platform Support> section, instead.
341 [ List changes as a =item entry ].
353 XXX Any significant changes to the testing of a freshly built perl should be
354 listed here. Changes which create B<new> files in F<t/> go here as do any
355 large changes to the testing harness (e.g. when parallel testing was added).
356 Changes to existing files in F<t/> aren't worth summarizing, although the bugs
357 that they represent may be covered elsewhere.
359 [ List each test improvement as a =item entry ]
369 =head1 Platform Support
371 XXX Any changes to platform support should be listed in the sections below.
373 [ Within the sections, list each platform as a =item entry with specific
374 changes as paragraphs below it. ]
378 XXX List any platforms that this version of perl compiles on, that previous
379 versions did not. These will either be enabled by new files in the F<hints/>
380 directories, or new subdirectories and F<README> files at the top level of the
385 =item XXX-some-platform
391 =head2 Discontinued Platforms
393 XXX List any platforms that this version of perl no longer compiles on.
397 =item XXX-some-platform
403 =head2 Platform-Specific Notes
405 XXX List any changes for specific platforms. This could include configuration
406 and compilation changes or changes in portability/compatibility. However,
407 changes within modules for platforms should generally be listed in the
408 L</Modules and Pragmata> section.
414 Perl can now be built in C++ mode on Windows by setting the makefile macro
415 C<USE_CPLUSPLUS> to the value "define".
417 List form pipe open no longer falls back to the shell.
421 =head1 Internal Changes
423 XXX Changes which affect the interface available to C<XS> code go here. Other
424 significant internal changes for future core maintainers should be noted as
427 [ List each change as a =item entry ]
437 =head1 Selected Bug Fixes
439 XXX Important bug fixes in the core language are summarized here. Bug fixes in
440 files in F<ext/> and F<lib/> are best summarized in L</Modules and Pragmata>.
442 [ List each fix as a =item entry ]
448 The original visible value of C<$/> is now preserved when it is set to
449 an invalid value. Previously if you set C<$/> to a reference to an
450 array, for example, perl would produce a runtime error and not set
451 C<PL_rs>, but perl code that checked C<$/> would see the array
452 reference. [perl #123218]
456 In a regular expression pattern, a POSIX class, like C<[:ascii:]>, must
457 be inside a bracketed character class, like C</qr[[:ascii:]]>. A
458 warning is issued when something looking like a POSIX class is not
459 inside a bracketed class. That warning wasn't getting generated when
460 the POSIX class was negated: C<[:^ascii:]>. This is now fixed.
464 Fix a couple of other size calculation overflows. [perl #123554]
468 A bug introduced in 5.21.6, C<dump LABEL> acted the same as C<goto
469 LABEL>. This has been fixed. [perl #123836]
473 =head1 Known Problems
475 XXX Descriptions of platform agnostic bugs we know we can't fix go here. Any
476 tests that had to be C<TODO>ed for the release would be noted here. Unfixed
477 platform specific bugs also go here.
479 [ List each fix as a =item entry ]
489 =head1 Errata From Previous Releases
495 XXX Add anything here that we forgot to add, or were mistaken about, in
496 the perldelta of a previous release.
502 XXX If any significant core contributor has died, we've added a short obituary
505 =head1 Acknowledgements
507 XXX Generate this with:
509 perl Porting/acknowledgements.pl v5.21.8..HEAD
511 =head1 Reporting Bugs
513 If you find what you think is a bug, you might check the articles recently
514 posted to the comp.lang.perl.misc newsgroup and the perl bug database at
515 https://rt.perl.org/ . There may also be information at
516 http://www.perl.org/ , the Perl Home Page.
518 If you believe you have an unreported bug, please run the L<perlbug> program
519 included with your release. Be sure to trim your bug down to a tiny but
520 sufficient test case. Your bug report, along with the output of C<perl -V>,
521 will be sent off to perlbug@perl.org to be analysed by the Perl porting team.
523 If the bug you are reporting has security implications, which make it
524 inappropriate to send to a publicly archived mailing list, then please send it
525 to perl5-security-report@perl.org. This points to a closed subscription
526 unarchived mailing list, which includes all the core committers, who will be
527 able to help assess the impact of issues, figure out a resolution, and help
528 co-ordinate the release of patches to mitigate or fix the problem across all
529 platforms on which Perl is supported. Please only use this address for
530 security issues in the Perl core, not for modules independently distributed on
535 The F<Changes> file for an explanation of how to view exhaustive details on
538 The F<INSTALL> file for how to build Perl.
540 The F<README> file for general stuff.
542 The F<Artistic> and F<Copying> files for copyright information.