5 perl5211delta - what is new for perl v5.21.1
9 This document describes differences between the 5.21.0 release and the 5.21.1
12 If you are upgrading from an earlier release such as 5.20.0, first read
13 L<perl5210delta>, which describes differences between 5.20.0 and 5.21.0.
17 This release removes a number of previously deprecated constructs, many
18 that have been around for a long time. Please see L</"Incompatible Changes">
21 =head1 Core Enhancements
23 =head2 Unicode 7.0 is now supported
25 For details on what is in this release, see
26 L<http://www.unicode.org/versions/Unicode7.0.0/>.
28 =head2 Experimental C Backtrace API
30 Starting from Perl 5.21.1, on some platforms Perl supports retrieving
31 the C level backtrace (similar to what symbolic debuggers like gdb do).
33 The backtrace returns the stack trace of the C call frames,
34 with the symbol names (function names), the object names (like "perl"),
35 and if it can, also the source code locations (file:line).
37 The supported platforms are Linux and OS X (some *BSD might work at
38 least partly, but they have not yet been tested).
40 The feature needs to be enabled with C<Configure -Dusecbacktrace>.
42 Also included is a C API to retrieve backtraces.
44 See L<perlhacktips/"C backtrace"> for more information.
46 =head2 C<qr/foo/x> now ignores any Unicode pattern white space
48 The C</x> regular expression modifier allows the pattern to contain
49 white space and comments, both of which are ignored, for improved
50 readability. Until now, not all the white space characters that Unicode
51 designates for this purpose were handled. The additional ones now
54 U+200E LEFT-TO-RIGHT MARK,
55 U+200F RIGHT-TO-LEFT MARK,
56 U+2028 LINE SEPARATOR,
58 U+2029 PARAGRAPH SEPARATOR.
60 =head2 S<C<use locale>> can restrict which locale categories are affected
62 It is now possible to pass a parameter to S<C<use locale>> to specify
63 a subset of locale categories to be locale-aware, with the remaining
64 ones unaffected. See L<perllocale/The "use locale" pragma> for details.
66 =head1 Incompatible Changes
68 =head2 C<\N{}> with a sequence of multiple spaces is now a fatal error.
70 This has been deprecated since v5.18.
72 =head2 In double-quotish C<\cI<X>>, I<X> must now be a printable ASCII character
74 In prior releases, failure to do this raised a deprecation warning.
76 =head2 Splitting the tokens C<(?> and C<(*> in regular expressions is
77 now a fatal compilation error.
79 These had been deprecated since v5.18.
81 =head2 5 additional characters are treated as white space under C</x> in
82 regex patterns (unless escaped)
84 The use of these characters with C</x> outside bracketed character
85 classes and when not preceded by a backslash has raised a deprecation
86 warning since v5.18. Now they will be ignored. See L</"qr/foo/x">
87 for the list of the five characters.
89 =head2 Comment lines within S<C<(?[ ])>> now are ended only by a C<\n>
91 S<C<(?[ ])>> is an experimental feature, introduced in v5.18. It operates
92 as if C</x> is always enabled. But there was a difference, comment
93 lines (following a C<#> character) were terminated by anything matching
94 C<\R> which includes all vertical whitespace, such as form feeds. For
95 consistency, this is now changed to match what terminates comment lines
96 outside S<C<(?[ ])>>, namely a C<\n> (even if escaped), which is the
97 same as what terminates a heredoc string and formats.
99 =head2 Omitting % and @ on hash and array names is no longer permitted
101 Really old Perl let you omit the @ on array names and the % on hash
102 names in some spots. This has issued a deprecation warning since Perl
103 5.0, and is no longer permitted.
105 =head2 C<"$!"> text is now in English outside C<"use locale"> scope
107 Previously, the text, unlike almost everything else, always came out
108 based on the current underlying locale of the program. (Also affected
109 on some systems is C<"$^E>".) For programs that are unprepared to
110 handle locale, this can cause garbage text to be displayed. It's better
111 to display text that is translatable via some tool than garbage text
112 which is much harder to figure out.
114 =head2 C<"$!"> text will be returned in UTF-8 when appropriate
116 The stringification of C<$!> and C<$^E> will have the UTF-8 flag set
117 when the text is actually non-ASCII UTF-8. This will enable programs
118 that are set up to be locale-aware to properly output messages in the
119 user's native language. Code that needs to continue the 5.20 and
120 earlier behavior can do the stringification within the scopes of both
121 'use bytes' and 'use locale ":messages". No other Perl operations will
122 be affected by locale; only C<$!> and C<$^E> stringification. The
123 'bytes' pragma causes the UTF-8 flag to not be set, just as in previous
124 Perl releases. This resolves [perl #112208].
126 =head2 Support for C<?PATTERN?> without explicit operator has been removed
128 Starting regular expressions matching only once directly with the
129 question mark delimiter is now a syntax error, so that the question mark
130 can be available for use in new operators. Write C<m?PATTERN?> instead,
131 explicitly using the C<m> operator: the question mark delimiter still
132 invokes match-once behaviour.
134 =head2 C<defined(@array)> and C<defined(%hash)> are now fatal errors
136 These have been deprecated since v5.6.1 and have raised deprecation
137 warnings since v5.16.
139 =head2 Using a hash or an array as a reference are now fatal errors.
141 For example, C<%foo-E<gt>{"bar"}> now causes a fatal compilation
142 error. These have been deprecated since before v5.8, and have raised
143 deprecation warnings since then.
147 =head2 Using a NO-BREAK space in a character alias for C<\N{...}> is now
150 This non-graphic character is essentially indistinguishable from a
151 regular space, and so should not be allowed. See
152 L<charnames/CUSTOM ALIASES>.
154 =head2 A literal C<"{"> should now be escaped in a pattern
156 If you want a literal left curly bracket (also called a left brace) in a
157 regular expression pattern, you should now escape it by either
158 preceding it with a backslash (C<"\{">) or enclosing it within square
159 brackets C<"[{]">, or by using C<\Q>; otherwise a deprecation warning
160 will be raised. This was first announced as forthcoming in the v5.16
161 release; it will allow future extensions to the language to happen.
163 =head1 Performance Enhancements
169 Many internal functions have been refactored to improve performance and reduce
170 their memory footprints.
172 L<[perl #121436]|https://rt.perl.org/Ticket/Display.html?id=121436>
173 L<[perl #121906]|https://rt.perl.org/Ticket/Display.html?id=121906>
174 L<[perl #121969]|https://rt.perl.org/Ticket/Display.html?id=121969>
178 C<-T> and C<-B> filetests will return sooner when an empty file is detected.
180 L<perl #121489|https://rt.perl.org/Ticket/Display.html?id=121489>
184 =head1 Modules and Pragmata
186 =head2 Updated Modules and Pragmata
192 The libnet collection of modules has been upgraded from version 1.25 to 1.27.
194 There are only whitespace changes to the installed files.
198 A mismatch between the documentation and the code in utf8::downgrade()
199 was fixed in favour of the documentation. The optional second argument
200 is now correctly treated as a perl boolean (true/false semantics) and
205 The Locale-Codes collection of modules has been upgraded from version 3.30 to 3.31.
207 Fixed a bug in the scripts used to extract data from spreadsheets that
208 prevented the SHP currency code from being found.
209 L<[cpan #94229]|https://rt.cpan.org/Ticket/Display.html?id=94229>
213 L<Archive::Tar> has been upgraded from version 1.96 to 2.00.
217 L<autodie> has been upgraded from version 2.23 to 2.25.
221 L<B> has been upgraded from version 1.48 to 1.49.
225 L<B::Deparse> has been upgraded from version 1.26 to 1.27.
229 L<Benchmark> has been upgraded from version 1.18 to 1.19.
233 L<Carp> has been upgraded from version 1.3301 to 1.34.
235 Carp::Heavy now ignores version mismatches with Carp if Carp is newer
236 than 1.12, since Carp::Heavy's guts were merged into Carp at that
238 L<[perl #121574]|https://rt.perl.org/Ticket/Display.html?id=121574>
242 L<charnames> has been upgraded from version 1.40 to 1.41.
246 L<CPAN::Meta> has been upgraded from version 2.140640 to 2.141520.
250 L<Data::Dumper> has been upgraded from version 2.151 to 2.152.
252 Changes to resolve Coverity issues.
254 XS dumps incorrectly stored the name of code references stored in a
256 L<[perl #122070]|https://rt.perl.org/Ticket/Display.html?id=122070>
260 L<Devel::Peek> has been upgraded from version 1.16 to 1.17.
264 L<Devel::PPPort> has been upgraded from version 3.21 to 3.24.
268 L<Digest::SHA> has been upgraded from version 5.88 to 5.92.
272 L<DynaLoader> has been upgraded from version 1.25 to 1.26.
276 L<Encode> has been upgraded from version 2.60 to 2.62.
278 B<piconv> now has better error handling when the encoding name is nonexistent,
279 and a build breakage when upgrading L<Encode> in perl-5.8.2 and earlier has
284 L<Errno> has been upgraded from version 1.20_03 to 1.20_04.
288 L<Exporter> has been upgraded from version 5.70 to 5.71.
292 L<ExtUtils::Install> has been upgraded from version 1.67 to 1.68.
296 L<ExtUtils::Miniperl> has been upgraded from version 1.01 to 1.02.
300 L<ExtUtils::ParseXS> has been upgraded from version 3.24 to 3.25.
304 L<ExtUtils::Typemaps> has been upgraded from version 3.24 to 3.25.
308 L<File::Spec> has been upgraded from version 3.47 to 3.48.
312 L<Hash::Util> has been upgraded from version 0.16 to 0.17.
314 Minor bug fixes and documentation fixes to Hash::Util::hash_stats()
318 L<IO> has been upgraded from version 1.31 to 1.32.
322 L<List::Util> has been upgraded from version 1.38 to 1.39.
326 L<locale> has been upgraded from version 1.03 to 1.04.
330 L<Locale::Codes> has been upgraded from version 3.30 to 3.31.
334 L<Math::BigInt> has been upgraded from version 1.9993 to 1.9995.
336 Synchronize POD changes from the CPAN release.
338 C<< Math::BigFloat->blog(x) >> would sometimes return blog(2*x) when
339 the accuracy was greater than 70 digits.
341 The result of C<< Math::BigFloat->bdiv() >> in list context now
342 satisfies C<< x = quotient * divisor + remainder >>.
346 L<Math::BigRat> has been upgraded from version 0.2606 to 0.2608.
348 Synchronize POD changes from the CPAN release.
352 L<Module::CoreList> has been upgraded from version 5.021001 to 5.021001_01.
356 L<Module::Metadata> has been upgraded from version 1.000019 to 1.000024.
358 Support installations on older perls with an L<ExtUtils::MakeMaker> earlier
363 L<NDBM_File> has been upgraded from version 1.12 to 1.13.
367 L<OS2::Process> has been upgraded from version 1.09 to 1.10.
371 L<perl5db.pl> has been upgraded from version 1.44 to 1.45.
373 fork() in the debugger under C<tmux> will now create a new window for
374 the forked process. L<[perl
375 #121333]|https://rt.perl.org/Ticket/Display.html?id=121333>
377 The debugger now saves the current working directory on startup and
378 restores it when you restart your program with C<R> or C<rerun>. L<[perl
379 #121509]|https://rt.perl.org/Ticket/Display.html?id=121509>
383 L<PerlIO::encoding> has been upgraded from version 0.18 to 0.19.
385 No changes in behaviour.
389 L<PerlIO::mmap> has been upgraded from version 0.011 to 0.013.
391 No changes in behaviour.
395 L<PerlIO::scalar> has been upgraded from version 0.18 to 0.19.
397 No changes in behaviour.
401 L<PerlIO::via> has been upgraded from version 0.14 to 0.15.
405 L<Pod::Html> has been upgraded from version 1.21 to 1.22.
409 L<POSIX> has been upgraded from version 1.38_03 to 1.40.
413 L<Scalar::Util> has been upgraded from version 1.38 to 1.39.
417 L<SelfLoader> has been upgraded from version 1.21 to 1.22.
421 L<Socket> has been upgraded from version 2.013 to 2.014.
425 L<Storable> has been upgraded from version 2.49 to 2.51.
429 L<Term::ANSIColor> has been upgraded from version 4.02 to 4.03.
433 L<Test::Harness> has been upgraded from version 3.30 to 3.32.
437 L<Test::Simple> has been upgraded from version 1.001002 to 1.001003.
441 L<threads> has been upgraded from version 1.93 to 1.94.
445 L<Tie::File> has been upgraded from version 1.00 to 1.01.
449 L<Unicode::Collate> has been upgraded from version 1.04 to 1.07.
451 Version 0.67's improved discontiguous contractions is invalidated by default
452 and is supported as a parameter 'long_contraction'.
456 L<Unicode::Normalize> has been upgraded from version 1.17 to 1.18.
458 The XSUB implementation has been removed in favour of pure Perl.
462 L<Unicode::UCD> has been upgraded from version 0.57 to 0.58.
466 L<utf8> has been upgraded from version 1.13 to 1.14.
470 L<warnings> has been upgraded from version 1.23 to 1.24.
476 =head2 Changes to Existing Documentation
484 C<-l> now notes that it will return false if symlinks aren't supported by the
487 L<[perl #121523]|https://rt.perl.org/Ticket/Display.html?id=121523>
491 Note that C<exec LIST> and C<system LIST> may fall back to the shell on
492 Win32. Only C<exec PROGRAM LIST> and C<system PROGRAM LIST> indirect object
493 syntax will reliably avoid using the shell.
495 This has also been noted in L<perlport>.
497 L<[perl #122046]|https://rt.perl.org/Ticket/Display.html?id=122046>
507 Note that C<SvSetSV> doesn't do set magic.
511 C<sv_usepvn_flags> - Fix documentation to mention the use of C<NewX> instead of
514 L<[perl #121869]|https://rt.perl.org/Ticket/Display.html?id=121869>
518 Clarify where C<NUL> may be embedded or is required to terminate a string.
522 Previously missing documentation due to formatting errors are now included.
526 Entries are now organized into groups rather than by file where they are found.
530 Alphabetical sorting of entries is now handled by the POD generator to make
531 entries easier to find when scanning.
535 =head3 L<perlhacktips>
541 Updated documentation for the C<test.valgrind> C<make> target.
543 L<[perl #121431]|https://rt.perl.org/Ticket/Display.html?id=121431>
553 The C</x> modifier has been clarified to note that comments cannot be continued
554 onto the next line by escaping them.
558 =head3 L<Unicode::UCD>
564 The documentation includes many clarifications and fixes.
570 The following additions or changes have been made to diagnostic output,
571 including warnings and fatal error messages. For the complete list of
572 diagnostic messages, see L<perldiag>.
574 =head2 New Diagnostics
582 L<In '(?...)', the '(' and '?' must be adjacent in regex; marked by S<<-- HERE> in mE<sol>%sE<sol>|perldiag/"In '(?...)', the '(' and '?' must be adjacent in regex; marked by <-- HERE in m/%s/">
584 (F) The two-character sequence C<"(?"> in
585 this context in a regular expression pattern should be an
586 indivisible token, with nothing intervening between the C<"(">
587 and the C<"?">, but you separated them.
591 L<In '(*VERB...)', the '(' and '*' must be adjacent in regex; marked by S<<-- HERE> in mE<sol>%sE<sol>|perldiag/"In '(*VERB...)', the '(' and '*' must be adjacent in regex; marked by <-- HERE in m/%s/">
593 (F) The two-character sequence C<"(*"> in
594 this context in a regular expression pattern should be an
595 indivisible token, with nothing intervening between the C<"(">
596 and the C<"*">, but you separated them.
600 L<charnames alias definitions may not contain a sequence of multiple spaces|perldiag/"charnames alias definitions may not contain a sequence of multiple spaces">
602 (F) You defined a character name which had multiple space
603 characters in a row. Change them to single spaces. Usually these
604 names are defined in the C<:alias> import argument to C<use charnames>, but
605 they could be defined by a translator installed into C<$^H{charnames}>.
606 See L<charnames/CUSTOM ALIASES>.
610 L<charnames alias definitions may not contain trailing white-space|perldiag/"charnames alias definitions may not contain trailing white-space">
612 (F) You defined a character name which ended in a space
613 character. Remove the trailing space(s). Usually these names are
614 defined in the C<:alias> import argument to C<use charnames>, but they
615 could be defined by a translator installed into C<$^H{charnames}>.
616 See L<charnames/CUSTOM ALIASES>.
620 L<Can't use a hash as a reference|perldiag/"Can't use a hash as a reference">
622 (F) You tried to use a hash as a reference, as in
623 C<< %foo->{"bar"} >> or C<< %$ref->{"hello"} >>. Versions of perl E<lt>= 5.6.1
624 used to allow this syntax, but shouldn't have.
628 L<Can't use an array as a reference|perldiag/"Can't use an array as a reference">
630 (F) You tried to use an array as a reference, as in
631 C<< @foo->[23] >> or C<< @$ref->[99] >>. Versions of perl E<lt>= 5.6.1 used to
632 allow this syntax, but shouldn't have.
636 L<Can't use 'defined(@array)' (Maybe you should just omit the defined()?)|perldiag/"Can't use 'defined(@array)' (Maybe you should just omit the defined()?)">
638 (F) defined() is not useful on arrays because it
639 checks for an undefined I<scalar> value. If you want to see if the
640 array is empty, just use C<if (@array) { # not empty }> for example.
644 L<Can't use 'defined(%hash)' (Maybe you should just omit the defined()?)|perldiag/"Can't use 'defined(%hash)' (Maybe you should just omit the defined()?)">
646 (F) C<defined()> is not usually right on hashes.
648 Although C<defined %hash> is false on a plain not-yet-used hash, it
649 becomes true in several non-obvious circumstances, including iterators,
650 weak references, stash names, even remaining true after C<undef %hash>.
651 These things make C<defined %hash> fairly useless in practice, so it now
652 generates a fatal error.
654 If a check for non-empty is what you wanted then just put it in boolean
655 context (see L<perldata/Scalar values>):
661 If you had C<defined %Foo::Bar::QUUX> to check whether such a package
662 variable exists then that's never really been reliable, and isn't
663 a good way to enquire about the features of a package, or whether
668 L<Illegal suidscript|perldiag/"Illegal suidscript">
670 (F) The script run under suidperl was somehow illegal.
680 L<Unescaped left brace in regex is deprecated, passed through in regex; marked by <-- HERE in mE<sol>%sE<sol>|perldiag/"Unescaped left brace in regex is deprecated, passed through in regex; marked by <-- HERE in m/%s/">
682 (D deprecated, regexp) You used a literal C<"{"> character in a regular
683 expression pattern. You should change to use C<"\{"> instead, because a future
684 version of Perl (tentatively v5.26) will consider this to be a syntax error. If
685 the pattern delimiters are also braces, any matching right brace
686 (C<"}">) should also be escaped to avoid confusing the parser, for
693 L<NO-BREAK SPACE in a charnames alias definition is deprecated|perldiag/"NO-BREAK SPACE in a charnames alias definition is deprecated">
695 (D deprecated) You defined a character name which contained a no-break
696 space character. Change it to a regular space. Usually these names are
697 defined in the C<:alias> import argument to C<use charnames>, but they
698 could be defined by a translator installed into C<$^H{charnames}>. See
699 L<charnames/CUSTOM ALIASES>.
703 L<PerlIO layer ':win32' is experimental|perldiag/"PerlIO layer ':win32' is experimental">
705 (S experimental::win32_perlio) The C<:win32> PerlIO layer is
706 experimental. If you want to take the risk of using this layer,
707 simply disable this warning:
709 no warnings "experimental::win32_perlio";
713 L<Negative repeat count does nothing|perldiag/"Negative repeat count does nothing">
715 (W numeric) You tried to execute the
716 L<C<x>|perlop/Multiplicative Operators> repetition operator fewer than 0
717 times, which doesn't make sense.
721 L<localtime(%f) failed|perldiag/"localtime(%f) failed">
723 (W overflow) You called C<localtime> with a number that it could not handle:
724 too large, too small, or NaN. The returned value is C<undef>.
728 L<gmtime(%f) failed|perldiag/"gmtime(%f) failed">
730 (W overflow) You called C<gmtime> with a number that it could not handle:
731 too large, too small, or NaN. The returned value is C<undef>.
735 L<PerlIO layer ':win32' is experimental|perldiag/"PerlIO layer ':win32' is experimental">:
737 (S experimental::win32_perlio) The C<:win32> PerlIO layer is
738 experimental. If you want to take the risk of using this layer,
739 simply disable this warning:
741 no warnings "experimental::win32_perlio";
745 L<Negative repeat count does nothing|perldiag/"Negative repeat count does nothing">
747 (W numeric) This warns when the repeat count of the
748 L<C<x>|perlop/Multiplicative Operators> repetition operator is
751 This warning may be changed or removed if it turn out that it was
752 unwise to have added it.
756 =head2 Changes to Existing Diagnostics
762 L<Variable length lookbehind not implemented in regex mE<sol>%sE<sol>|perldiag/"Variable length lookbehind not implemented in regex m/%s/">
764 Information about Unicode behaviour has been added.
770 This warning has been changed to
771 L<< <> at require-statement should be quotes|perldiag/"<> at require-statement should be quotes" >>
772 to make the issue more identifiable.
776 L<Unsuccessful %s on filename containing newline|perldiag/"Unsuccessful %s on filename containing newline">
778 This warning is now only produced when the newline is at the end of
783 =head1 Utility Changes
791 The F<x2p/> directory has been removed from the Perl core.
793 This removes find2perl, s2p and a2p. They have all been released to CPAN as
794 separate distributions (App::find2perl, App::s2p, App::a2p).
798 =head1 Configuration and Compilation
804 C<make test.valgrind> now supports parallel testing.
808 TEST_JOBS=9 make test.valgrind
810 See L<perlhacktips/valgrind> for more information.
812 L<[perl #121431]|https://rt.perl.org/Ticket/Display.html?id=121431>
816 The MAD (Misc Attribute Decoration) build option has been removed
818 This was an unmaintained attempt at preserving
819 the Perl parse tree more faithfully so that automatic conversion of
820 Perl 5 to Perl 6 would have been easier.
822 This build-time configuration option had been unmaintained for years,
823 and had probably seriously diverged on both Perl 5 and Perl 6 sides.
827 =head1 Platform Support
829 =head2 Discontinued Platforms
833 =item NeXTSTEP/OPENSTEP
835 NeXTSTEP was proprietary OS bundled with NeXT's workstations in the early
836 to mid 90's; OPENSTEP was an API specification that provided a NeXTSTEP-like
837 environment on a non-NeXTSTEP system. Both are now long dead, so support
838 for building Perl on them has been removed.
842 =head2 Platform-Specific Notes
848 On OpenBSD, Perl will now default to using the system C<malloc> due to the
849 security features it provides. Perl's own malloc wrapper has been in use
850 since v5.14 due to performance reasons, but the OpenBSD project believes
851 the tradeoff is worth it and would prefer that users who need the speed
852 specifically ask for it.
854 L<[perl #122000]|https://rt.perl.org/Ticket/Display.html?id=122000>.
858 =head1 Internal Changes
864 The deprecated variable C<PL_sv_objcount> has been removed.
868 Perl now tries to keep the locale category C<LC_NUMERIC> set to "C"
869 except around operations that need it to be set to the program's
870 underlying locale. This protects the many XS modules that cannot cope
871 with the decimal radix character not being a dot. Prior to this
872 release, Perl initialized this category to "C", but a call to
873 C<POSIX::setlocale()> would change it. Now such a call will change the
874 underlying locale of the C<LC_NUMERIC> category for the program, but the
875 locale exposed to XS code will remain "C". There is an API under
876 development for those relatively few modules that need to use the
877 underlying locale. This API will be nailed down during the course of
878 developing v5.21. Send email to L<mailto:perl5-porters@perl.org> for
883 A new macro L<C<isUTF8_CHAR>|perlapi/isUTF8_CHAR> has been written which
884 efficiently determines if the string given by its parameters begins
885 with a well-formed UTF-8 encoded character.
889 =head1 Selected Bug Fixes
895 index() and rindex() no longer crash when used on strings over 2GB in
897 L<[perl #121562]|https://rt.perl.org/Ticket/Display.html?id=121562>.
901 A small previously intentional memory leak in PERL_SYS_INIT/PERL_SYS_INIT3 on
902 Win32 builds was fixed. This might affect embedders who repeatedly create and
903 destroy perl engines within the same process.
907 C<POSIX::localeconv()> now returns the data for the program's underlying
908 locale even when called from outside the scope of S<C<use locale>>.
912 C<POSIX::localeconv()> now works properly on platforms which don't have
913 C<LC_NUMERIC> and/or C<LC_MONETARY>, or for which Perl has been compiled
914 to disregard either or both of these locale categories. In such
915 circumstances, there are now no entries for the corresponding values in
916 the hash returned by C<localeconv()>.
920 C<POSIX::localeconv()> now marks appropriately the values it returns as
921 UTF-8 or not. Previously they were always returned as a bytes, even if
922 they were supposed to be encoded as UTF-8.
926 On Microsoft Windows, within the scope of C<S<use locale>>, the following
927 POSIX character classes gave results for many locales that did not
928 conform to the POSIX standard:
941 These are because the underlying Microsoft implementation does not
942 follow the standard. Perl now takes special precautions to correct for
947 Many issues have been detected by L<Coverity|http://www.coverity.com/> and
952 system() and friends should now work properly on more Android builds.
954 Due to an oversight, the value specified through -Dtargetsh to Configure
955 would end up being ignored by some of the build process. This caused perls
956 cross-compiled for Android to end up with defective versions of system(),
957 exec() and backticks: the commands would end up looking for C</bin/sh>
958 instead of C</system/bin/sh>, and so would fail for the vast majority
959 of devices, leaving C<$!> as C<ENOENT>.
963 C<qr(...\(...\)...)>,
964 C<qr[...\[...\]...]>,
967 now work. Previously it was impossible to escape these three
968 left-characters with a backslash within a regular expression pattern
969 where otherwise they would be considered metacharacters, and the pattern
970 opening delimiter was the character, and the closing delimiter was its
975 =head1 Acknowledgements
977 Perl 5.21.1 represents approximately 3 weeks of development since Perl 5.21.0
978 and contains approximately 240,000 lines of changes across 680 files from 37
981 Excluding auto-generated files, documentation and release tools, there were
982 approximately 150,000 lines of changes to 420 .pm, .t, .c and .h files.
984 Perl continues to flourish into its third decade thanks to a vibrant community
985 of users and developers. The following people are known to have contributed the
986 improvements that became Perl 5.21.1:
988 Alex Solovey, Andrew Fresh, Andy Dougherty, Brian Fraser, Chris 'BinGOs'
989 Williams, Craig A. Berry, Dagfinn Ilmari Mannsåker, Daniel Dragan, Darin
990 McBride, David Mitchell, Doug Bell, H.Merijn Brand, James E Keenan, Jarkko
991 Hietaniemi, kafka, Karen Etheridge, Karl Williamson, Leon Timmermans, Matthew
992 Horsfall, Michael Bunk, Nicholas Clark, Niels Thykier, Norman Koch, Peter John
993 Acklam, Pierre Bogossian, Reini Urban, Ricardo Signes, Rob Hoelz, Shlomi Fish,
994 Smylers, Steffen Müller, Steve Hay, Sullivan Beck, Thomas Sibley, Todd
995 Rinaldo, Tony Cook, Yves Orton.
997 The list above is almost certainly incomplete as it is automatically generated
998 from version control history. In particular, it does not include the names of
999 the (very much appreciated) contributors who reported issues to the Perl bug
1002 Many of the changes included in this version originated in the CPAN modules
1003 included in Perl's core. We're grateful to the entire CPAN community for
1004 helping Perl to flourish.
1006 For a more complete list of all of Perl's historical contributors, please see
1007 the F<AUTHORS> file in the Perl source distribution.
1009 =head1 Reporting Bugs
1011 If you find what you think is a bug, you might check the articles recently
1012 posted to the comp.lang.perl.misc newsgroup and the perl bug database at
1013 https://rt.perl.org/ . There may also be information at
1014 http://www.perl.org/ , the Perl Home Page.
1016 If you believe you have an unreported bug, please run the L<perlbug> program
1017 included with your release. Be sure to trim your bug down to a tiny but
1018 sufficient test case. Your bug report, along with the output of C<perl -V>,
1019 will be sent off to perlbug@perl.org to be analysed by the Perl porting team.
1021 If the bug you are reporting has security implications, which make it
1022 inappropriate to send to a publicly archived mailing list, then please send it
1023 to perl5-security-report@perl.org. This points to a closed subscription
1024 unarchived mailing list, which includes all the core committers, who will be
1025 able to help assess the impact of issues, figure out a resolution, and help
1026 co-ordinate the release of patches to mitigate or fix the problem across all
1027 platforms on which Perl is supported. Please only use this address for
1028 security issues in the Perl core, not for modules independently distributed on
1033 The F<Changes> file for an explanation of how to view exhaustive details on
1036 The F<INSTALL> file for how to build Perl.
1038 The F<README> file for general stuff.
1040 The F<Artistic> and F<Copying> files for copyright information.