5 perldelta - what is new for perl v5.34.0
9 This document describes differences between the 5.32.0 release and the 5.34.0
12 If you are upgrading from an earlier release such as 5.30.0, first read
13 L<perl5320delta>, which describes differences between 5.30.0 and 5.32.0.
15 =head1 Core Enhancements
17 =head2 Experimental Try/Catch Syntax
19 An initial experimental attempt at providing C<try>/C<catch> notation has
28 warn "An error occurred: $e";
31 For more information, see L<perlsyn/"Try Catch Exception Handling">.
33 =head2 C<qr/{,n}/> is now accepted
35 An empty lower bound is now accepted for regular expression quantifiers,
38 =head2 Blanks freely allowed within but adjacent to curly braces
40 (in double-quotish contexts and regular expression patterns)
42 This means you can write things like S<C<\x{ FFFC }>> if you like. This
43 applies to all such constructs, namely C<\b{}>, C<\g{}>, C<\k{}>,
44 C<\N{}>, C<\o{}>, and C<\x{}>; as well as the regular expression
45 quantifier C<{I<m>,I<n>}>. C<\p{}> and C<\P{}> retain their
46 already-existing, even looser, rules mandated by the Unicode standard
47 (see L<perluniprops/Properties accessible through \p{} and \P{}>).
49 This ability is in effect regardless of the presence of the C</x>
50 regular expression pattern modifier.
52 Additionally, the comma in a regular expression braced quantifier may
53 have blanks (tabs or spaces) before and/or after the comma, like
56 =head2 New octal syntax C<0oI<ddddd>>
58 It is now possible to specify octal literals with C<0o> prefixes,
59 as in C<0o123_456>, parallel to the existing construct to specify
60 hexadecimal literal C<0xI<ddddd>> and binary literal C<0bI<ddddd>>.
61 Also, the builtin C<oct()> function now accepts this new syntax.
63 See L<perldata/Scalar value constructors> and L<perlfunc/oct EXPR>.
65 =head1 Performance Enhancements
71 Fix a memory leak in RegEx (L<GH #18604|https://github.com/Perl/perl5/issues/18604>)
75 =head1 Modules and Pragmata
77 =head2 New Modules and Pragmata
83 L<ExtUtils::PL2Bat> 0.002 has been added to the Perl core.
85 This module is a generalization of the C<pl2bat> script. It being a script has led
86 to at least two forks of this code; this module will unify them under one
87 implementation with tests.
91 =head2 Updated Modules and Pragmata
97 L<Archive::Tar> has been upgraded from version 2.36 to 2.38.
101 L<autodie> has been upgraded from version 2.32 to 2.34.
105 L<B> has been upgraded from version 1.80 to 1.82.
109 L<B::Deparse> has been upgraded from version 1.54 to 1.56.
113 L<bytes> has been upgraded from version 1.07 to 1.08.
117 L<Carp> has been upgraded from version 1.50 to 1.52.
121 L<Compress::Raw::Bzip2> has been upgraded from version 2.093 to 2.101.
125 L<Compress::Raw::Zlib> has been upgraded from version 2.093 to 2.101.
129 L<Config::Perl::V> has been upgraded from version 0.32 to 0.33.
133 L<CPAN> has been upgraded from version 2.27 to 2.28.
137 L<Data::Dumper> has been upgraded from version 2.174 to 2.179.
141 L<DB> has been upgraded from version 1.58 to 1.59.
145 L<DB_File> has been upgraded from version 1.853 to 1.855.
149 L<Devel::Peek> has been upgraded from version 1.28 to 1.30.
153 L<Devel::PPPort> has been upgraded from version 3.57 to 3.62.
155 New C<PERL_VERSION_*> comparison macros are now available.
157 C<ppport.h --api-info> no longer includes non-API info unless that is the only match
161 L<Digest> has been upgraded from version 1.17_01 to 1.19.
165 L<Digest::MD5> has been upgraded from version 2.55_01 to 2.58.
169 L<DynaLoader> has been upgraded from version 1.47 to 1.50.
173 L<Encode> has been upgraded from version 3.06 to 3.08.
177 L<Env> has been upgraded from version 1.04 to 1.05.
181 L<Errno> has been upgraded from version 1.30 to 1.33.
185 L<experimental> has been upgraded from version 0.022 to 0.024.
189 L<Exporter> has been upgraded from version 5.74 to 5.76.
193 L<ExtUtils::CBuilder> has been upgraded from version 0.280234 to 0.280236.
197 L<ExtUtils::Install> has been upgraded from version 2.14 to 2.20.
201 L<ExtUtils::MakeMaker> has been upgraded from version 7.44 to 7.62.
205 L<ExtUtils::Manifest> has been upgraded from version 1.72 to 1.73.
209 L<ExtUtils::Miniperl> has been upgraded from version 1.09 to 1.10.
213 L<ExtUtils::ParseXS> has been upgraded from version 3.40 to 3.43.
217 L<ExtUtils::PL2Bat> has been upgraded from version 0.002 to 0.004.
221 L<ExtUtils::Typemaps> has been upgraded from version 3.38 to 3.43.
225 L<Fcntl> has been upgraded from version 1.13 to 1.14.
229 L<feature> has been upgraded from version 1.58 to 1.64.
231 Added the default enabled C<bareword_filehandles> feature.
233 A new L<multidimensional|feature/"The 'multidimensional' feature">
234 feature has been added, which is enabled by
235 default but allows turning off L<multi-dimensional array
236 emulation|perldata/Multi-dimensional array emulation>.
240 L<File::Copy> has been upgraded from version 2.34 to 2.35.
244 L<File::Fetch> has been upgraded from version 0.56 to 1.00.
248 L<File::Find> has been upgraded from version 1.37 to 1.39.
252 L<File::Path> has been upgraded from version 2.16 to 2.18.
256 L<File::Spec> has been upgraded from version 3.78 to 3.80.
260 L<File::Temp> has been upgraded from version 0.2309 to 0.2311.
264 L<FindBin> has been upgraded from version 1.51 to 1.52.
268 L<Filter::Util::Call> has been upgraded from version 1.59 to 1.60.
272 L<GDBM_File> has been upgraded from version 1.18 to 1.19.
274 New functions and compatibility for newer versions of GDBM.
275 [L<GH #18435|https://github.com/Perl/perl5/pull/18435>]
279 L<Getopt::Long> has been upgraded from version 2.51 to 2.52.
283 L<Getopt::Std> has been upgraded from version 1.12 to 1.13.
287 L<Hash::Util> has been upgraded from version 0.23 to 0.25.
291 L<Hash::Util::FieldHash> has been upgraded from version 1.20 to 1.21.
295 L<I18N::LangTags> has been upgraded from version 0.44 to 0.45.
299 L<if> has been upgraded from version 0.0608 to 0.0609.
303 L<IO> has been upgraded from version 1.43 to 1.46.
305 IO::Socket now stores error messages in C<$IO::Socket::errstr>, in
306 addition to in C<$@>.
308 The C<error> method now reports the error state for both the input and
309 output streams for sockets and character devices. Similarly
310 C<clearerr> now clears the error state for both streams.
312 A spurious error reported for regular file handles has been
313 fixed in L<IO::Handle>. L<GH #18019|https://github.com/Perl/perl5/issues/18019>
317 IO-Compress has been upgraded from version 2.093 to 2.102.
319 bin/zipdetails version 2.02
323 L<IO::Socket::IP> has been upgraded from version 0.39 to 0.41.
327 L<IO::Zlib> has been upgraded from version 1.10 to 1.11.
331 L<IPC::SysV> has been upgraded from version 2.07 to 2.09.
335 L<JSON::PP> has been upgraded from version 4.04 to 4.06.
339 The libnet distribution has been upgraded from version 3.11 to 3.13.
343 L<locale> has been upgraded from version 1.09 to 1.10.
347 L<Math::Complex> has been upgraded from version 1.5901 to 1.5902.
351 L<MIME::Base64> has been upgraded from version 3.15 to 3.16.
355 L<Module::CoreList> has been upgraded from version 5.20200620 to 5.20210520.
359 L<Module::Load> has been upgraded from version 0.34 to 0.36.
363 L<Module::Load::Conditional> has been upgraded from version 0.70 to 0.74.
367 L<mro> has been upgraded from version 1.23 to 1.25_001.
371 L<Net::Ping> has been upgraded from version 2.72 to 2.74.
375 L<NEXT> has been upgraded from version 0.67_01 to 0.68.
379 L<ODBM_File> has been upgraded from version 1.16 to 1.17.
383 L<Opcode> has been upgraded from version 1.47 to 1.50.
387 L<overload> has been upgraded from version 1.31 to 1.33.
391 L<perlfaq> has been upgraded from version 5.20200523 to 5.20210411.
395 L<PerlIO::encoding> has been upgraded from version 0.28 to 0.30.
399 L<PerlIO::mmap> has been upgraded from version 0.016 to 0.017.
403 L<PerlIO::scalar> has been upgraded from version 0.30 to 0.31.
407 L<PerlIO::via::QuotedPrint> has been upgraded from version 0.08 to 0.09.
411 L<Pod::Checker> has been upgraded from version 1.73 to 1.74.
415 L<Pod::Html> has been upgraded from version 1.25 to 1.27.
419 L<Pod::Simple> has been upgraded from version 3.40 to 3.42.
423 L<Pod::Usage> has been upgraded from version 1.69 to 2.01.
427 L<POSIX> has been upgraded from version 1.94 to 1.97.
429 POSIX::signbit() behaviour has been improved.
430 [L<GH #18441|https://github.com/Perl/perl5/pull/18441>]
432 Documentation for C<asctime> clarifies that the result is always in English.
433 (Use C<strftime> for a localized result.)
437 L<re> has been upgraded from version 0.40 to 0.41.
439 (See under L</Internal Changes> for more information.)
443 L<Safe> has been upgraded from version 2.41 to 2.43.
447 L<Socket> has been upgraded from version 2.029 to 2.031.
451 L<Storable> has been upgraded from version 3.21 to 3.23.
455 L<strict> has been upgraded from version 1.11 to 1.12.
459 L<subs> has been upgraded from version 1.03 to 1.04.
463 L<Symbol> has been upgraded from version 1.08 to 1.09.
467 L<Test::Harness> has been upgraded from version 3.42 to 3.43.
471 L<Test::Simple> has been upgraded from version 1.302175 to 1.302183.
475 L<Text::Balanced> has been upgraded from version 2.03 to 2.04.
479 L<threads> has been upgraded from version 2.25 to 2.26.
483 L<threads::shared> has been upgraded from version 1.61 to 1.62.
487 L<Tie::RefHash> has been upgraded from version 1.39 to 1.40.
491 L<Time::HiRes> has been upgraded from version 1.9764 to 1.9767.
495 L<Time::Local> has been upgraded from version 1.28 to 1.30.
499 L<Unicode::Collate> has been upgraded from version 1.27 to 1.29.
503 L<Unicode::Normalize> has been upgraded from version 1.27 to 1.28.
507 L<utf8> has been upgraded from version 1.22 to 1.24.
511 L<version> has been upgraded from version 0.9924 to 0.9928.
515 L<warnings> has been upgraded from version 1.47 to 1.51.
519 L<Win32> has been upgraded from version 0.53 to 0.57.
521 Fix calling convention for C<PFNRegGetValueA>.
523 Added C<Win32::IsSymlinkCreationAllowed()>,
524 C<Win32::IsDeveloperModeEnabled()>, and C<Win32::GetProcessPrivileges()>.
526 Removed old code for versions before Windows 2000.
530 L<XS::APItest> has been upgraded from version 1.09 to 1.16.
534 L<XS::Typemap> has been upgraded from version 0.17 to 0.18.
540 =head2 New Documentation
542 =head3 L<perldocstyle> has been added to F<pod/>.
544 This document is a guide for the authorship and maintenance of the
545 documentation that ships with Perl.
549 This document describes the goals, scope, system, and rules for Perl's new
552 Other pod files, most notably L<perlpolicy>, were amended to reflect
555 =head2 Changes to Existing Documentation
557 We have attempted to update the documentation to reflect the changes
558 listed in this document. If you find any we have missed, open an issue
559 at L<https://github.com/Perl/perl5/issues>.
561 Additionally, the following selected changes have been made:
567 L<perlapi>, L<perlguts>, L<perlxs>, and L<perlxstut> now prefer C<SvPVbyte>
572 References to B<Pumpking> have been replaced with a more accurate term or B<Steering Council> where appropriate.
576 B<The Perl Steering Council> is now the fallback contact for security issues.
586 Efforts continue in improving the presentation of this document, and to
587 document more API elements.
591 =head3 L<perlcommunity>
597 The freenode IRC URL has been updated.
601 =head3 L<perldebguts>
607 Corrected the description of the scalar C<< ${"_<$filename"} >>
618 Now documents additional examples of "not imported" warnings.
628 The Perl FAQ was updated to CPAN version 5.20201107 with minor
639 L<my()|perlfunc/my> and L<state()|perlfunc/state> now explicitly warn
640 the reader that lexical variables should typically not be redeclared
641 within the same scope or statement.
642 L<[GH #18389]|https://github.com/Perl/perl5/issues/18389>
646 The L<localtime|perlfunc/localtime> entry has been improved and now
647 also states that the result of the function is always in English.
651 L<msgsnd()|perlfunc/msgsnd> documented a length field included in the
652 packed C<MSG> parameter to C<msgsnd()>, but there was no such field.
653 C<MSG> contains only the type and the message content.
657 Better explanation of what happens when C<sleep> is called with a zero or
662 Simplify the C<split()> documentation by removing the C<join()>s from the examples
663 L<[GH #18676]|https://github.com/Perl/perl5/issues/18676>
673 document how to create a remote-tracking branch for every PR
677 document how to get a PR as a local branch
687 L<perlguts> now explains in greater detail the need to consult C<SvUTF8>
688 when calling C<SvPV> (or variants). A new "How do I pass a Perl string to a C
689 library?" section in the same document discusses when to use which style of
690 macro to read an SV's string value.
694 Corrected C<my_rpeep> example in perlguts.
698 A section has been added on the formatted printing of special sizes.
708 The C<< <> >> and C<<< <<>> >>> operators are commonly referred to as
709 the diamond and double diamond operators respectively, but that wasn't
710 mentioned previously in their documentation.
714 Document range op behavior change.
718 =head3 L<perlpacktut>
724 Incorrect variables used in an example have been fixed.
734 Document that caller() does not see try{} blocks
738 A new example shows how a lexical C<my> variable can be declared
739 during the initialization of a C<for> loop.
749 Fix description of what Perl does with unencoded strings
755 The following additions or changes have been made to diagnostic output,
756 including warnings and fatal error messages. For the complete list of
757 diagnostic messages, see L<perldiag>.
759 =head2 New Diagnostics
767 L<Bareword filehandle "%s" not allowed under 'no feature "bareword_filehandles"'|perldiag/"Bareword filehandle "%s" not allowed under 'no feature "bareword_filehandles"'">
769 This accompanies the new L<bareword_filehandles|feature/"The 'bareword_filehandles' feature."> feature.
773 L<Multidimensional hash lookup is disabled|perldiag/"Multidimensional hash lookup is disabled">
775 This accompanies the new L<multidimensional|feature/"The 'multidimensional' feature"> feature.
785 L<Wide character in setenv key (encoding to utf8)|perldiag/"Wide character in %s">
787 Attempts to put wide characters into environment variable keys via C<%ENV> now
788 provoke this warning.
792 =head2 Changes to Existing Diagnostics
798 L<Error %s in expansion of %s|perldiag/"Error %s in expansion of %s">
800 An error was encountered in handling a user-defined property
801 (L<perlunicode/User-Defined Character Properties>). These are
802 programmer written subroutines, hence subject to errors that may
803 prevent them from compiling or running.
807 L<Infinite recursion in user-defined property|perldiag/"Infinite recursion in user-defined property">
809 A user-defined property (L<perlunicode/User-Defined Character Properties>)
810 can depend on the definitions of other user-defined
811 properties. If the chain of dependencies leads back to this property,
812 infinite recursion would occur, were it not for the check that raised
817 L<Timeout waiting for another thread to define \p{%s}|perldiag/"Timeout waiting for another thread to define \p{%s}">
819 The first time a user-defined property
820 (L<perlunicode/User-Defined Character Properties>) is used, its
821 definition is looked up and converted into an internal form for more
822 efficient handling in subsequent uses. There could be a race if two or
823 more threads tried to do this processing nearly simultaneously.
827 L<Unknown user-defined property name \p{%s}|perldiag/"Unknown user-defined property name \p{%s}">
829 You specified to use a property within the C<\p{...}> which was a
830 syntactically valid user-defined property, but no definition was found
835 L<Too few arguments for subroutine '%s' (got %d; expected %d)|perldiag/"Too few arguments for subroutine '%s' (got %d; expected %d)">
837 Subroutine argument-count mismatch errors now include the number of
838 given and expected arguments.
842 L<Too many arguments for subroutine '%s' (got %d; expected %d)|perldiag/"Too many arguments for subroutine '%s' (got %d; expected %d)">
844 Subroutine argument-count mismatch errors now include the number of
845 given and expected arguments.
849 L<Lost precision when %s %f by 1|perldiag/"Lost precision when %s %f by 1">
851 This warning was only issued for positive too-large values when
852 incrementing, and only for negative ones when decrementing.
853 It is now issued for both positive or negative too-large values.
854 [L<GH #18333|https://github.com/Perl/perl5/issues/18333>]
858 L<\K not permitted in lookahead/lookbehind in regex; marked by <-- HERE in mE<sol>%sE<sol>|perldiag/"\K not permitted in lookahead/lookbehind in regex; marked by <-- HERE in m/%s/">
860 This error was incorrectly produced in some cases involving nested
861 lookarounds. This has been fixed. [L<GH #18123|https://github.com/Perl/perl5/issues/18123>]
865 L<Use of uninitialized value%s|perldiag/"Use of uninitialized value%s">
867 This warning may now include the array or hash index when the
868 uninitialized value is the result of an element not found. This will
869 only happen if the index is a simple non-magical variable.
873 =head1 Utility Changes
875 =head2 L<perl5db.pl> (the debugger)
879 =item * New option: C<HistItemMinLength>
881 This option controls the minimum length a command must be to get stored in
882 history. Traditionally, this has been fixed at 2. Changes to the debugger
883 are often perilous, and new bugs should be reported so the debugger can be
886 =item * Fix to C<i> and C<l> commands
888 The C<i $var> and C<l $var> commands work again with lexical variables.
892 =head1 Configuration and Compilation
898 Prevented incpath to spill into libpth
902 Use realpath if available. (This might catch more duplicate paths.)
906 Only include real existing paths.
910 Filter inc paths out of libpth.
912 =item * stadtx hash support has been removed
914 stadtx support has been entirely removed. Previously, it could be requested
915 with C<PERL_HASH_FUNC_STADTX>, and was default in 64-bit builds. It has been
916 replaced with SipHash. SipHash has been more rigorously reviewed than stadtx.
920 A new probe checks for buggy libc implementations of the C<gcvt>/C<qgcvt>
922 [L<GH #18170|https://github.com/Perl/perl5/issues/18170>]
924 =item * C<-Dusedefaultstrict>
926 EXPERIMENTAL: Perl can now be built with L<strict> on by default (using the
927 configuration option C<-Dusedefaultstrict>.
929 These strict defaults do not apply when C<perl> is run via C<-e> or C<-E>.
931 This setting provides a diagnostic mechanism intended for development
932 purposes only and is thus undefined by default.
936 The minimum supported Bison version is now 2.4, and the maximum is 3.7.
940 Newer 64-bit versions of the Intel C/C++ compiler are now recognised
941 and have the correct flags set.
945 Added the F<Configure> option B<-Dusedefaultstrict> to enable strict by default
946 in perl programs when not invoked with B<-e> or B<-E>. This is a diagnostic
947 tool for development.
951 We now trap SIGBUS when F<Configure> checks for C<va_copy>.
953 On several systems the attempt to determine if we need C<va_copy> or similar
954 results in a SIGBUS instead of the expected SIGSEGV, which previously caused a
957 [L<GH #18148|https://github.com/Perl/perl5/issues/18148>]
963 Tests were added and changed to reflect the other additions and
964 changes in this release. Furthermore, these significant changes were
971 Split Config-dependent tests in F<t/opbasic/arith.t> to F<t/op/arith2.t>
975 F<t/re/opt.t> was added, providing a test harness for regexp optimization.
976 [L<GH #18213|https://github.com/Perl/perl5/pull/18213>]
980 A workaround for CPAN distributions needing dot in C<@INC> has been removed
981 [L<GH #18394|https://github.com/Perl/perl5/pull/18394>].
982 All distributions that previously required the workaround have now been
987 When testing in parallel on many-core platforms, you can now cause the
988 test suite to finish somewhat earlier, but with less logical ordering of
989 the tests, by setting
991 PERL_TEST_HARNESS_ASAP=1
993 while running the test suite.
997 =head1 Platform Support
1005 Allow building Perl on i386 9front systems (a fork of plan9).
1009 =head2 Updated Platforms
1015 Improve support for Plan9 on i386 platforms.
1017 =item MacOS (Darwin)
1019 The hints file for darwin has been updated to handle future MacOS versions
1020 beyond 10. L<GH #17946|https://github.com/Perl/perl5/issues/17946>
1024 =head2 Discontinued Platforms
1030 Support code relating to Symbian has been removed. Symbian was an
1031 operating system for mobile devices. The port was last updated in July
1032 2009, and the platform itself in October 2012.
1036 =head2 Platform-Specific Notes
1042 Tests were updated to workaround DragonFlyBSD bugs in L<tc*()
1043 functions|https://bugs.dragonflybsd.org/issues/3252> and L<ctime
1044 updates|https://bugs.dragonflybsd.org/issues/3251>.
1048 A number of system libraries no longer exist as actual files on Big Sur,
1049 even though C<dlopen> will pretend they do, so now we fall back to C<dlopen>
1050 if a library file can not be found.
1051 [L<GH #18407|https://github.com/Perl/perl5/issues/18407>]
1055 Reading non-ASCII characters from the console when its codepage was set to
1056 65001 (UTF-8) was broken due to a bug in Windows. A workaround for this
1057 problem has been implemented.
1058 [L<GH #18701|https://github.com/Perl/perl5/issues/18701>]
1060 Building with mingw.org compilers (version 3.4.5 or later) using mingw runtime
1061 versions < 3.22 now works again. This was broken in Perl 5.31.4.
1063 Building with mingw.org compilers (version 3.4.5 or later) using mingw runtime
1064 versions >= 3.21 now works (for compilers up to version 5.3.0).
1066 F<Makefile.mk>, and thus support for dmake, has been removed. It is still possible
1067 to build Perl on Windows using nmake (Makefile) and GNU make (GNUmakefile).
1068 [L<GH #18511|https://github.com/Perl/perl5/pull/18511>]
1070 perl can now be built with C<USE_QUADMATH> on MS Windows using
1071 (32-bit and 64-bit) mingw-w64 ports of gcc.
1072 [L<GH #18465|https://github.com/Perl/perl5/pull/18465>]
1074 The F<pl2bat.pl> utility now needs to C<use ExtUtils::PL2Bat>. This could
1075 cause failures in parallel builds.
1077 Windows now supports L<symlink()|perlfunc/symlink> and
1078 L<readlink()|perlfunc/readlink>, and L<lstat()|perlfunc/lstat> is no
1079 longer an alias for L<stat()|perlfunc/stat>.
1080 L<[GH #18005]|https://github.com/Perl/perl5/issues/18005>.
1082 Unlike POSIX systems, creating a symbolic link on Windows requires
1083 either elevated privileges or Windows 10 1703 or later with Developer
1086 stat(), including C<stat FILEHANDLE>, and lstat() now uses our own
1087 implementation that populates the device C<dev> and inode numbers
1088 C<ino> returned rather than always returning zero. The number of
1089 links C<nlink> field is now always populated.
1091 L<< C<${^WIN32_SLOPPY_STAT}> |perlvar/${^WIN32_SLOPPY_STAT} >> previously
1092 controlled whether the C<nlink> field was populated requiring a
1093 separate Windows API call to fetch, since C<nlink> and the other
1094 information required for C<stat()> is now retrieved in a single API call.
1096 The C<-r> and C<-w> operators now return true for the C<STDIN>,
1097 C<STDOUT> and C<STDERR> handles. Unfortunately it still won't return
1098 true for duplicates of those handles.
1099 L<[GH #8502]|https://github.com/Perl/perl5/issues/8502>.
1101 The times returned by stat() and lstat() are no longer incorrect
1102 across Daylight Savings Time adjustments.
1103 L<[GH #6080]|https://github.com/Perl/perl5/issues/6080>.
1105 C<-x> on a filehandle should now match C<-x> on the corresponding
1106 filename on Vista or later.
1107 L<[GH #4145]|https://github.com/Perl/perl5/issues/4145>.
1109 C<-e '"'> no longer incorrectly returns true.
1110 L<[GH #12431]|https://github.com/Perl/perl5/issues/12431>.
1112 The same manifest is now used for Visual C++ and gcc builds.
1114 Previously, MSVC builds were using the B</manifestdependency> flag instead of
1115 embedding F<perlexe.manifest>, which caused issues such as C<GetVersionEx()>
1116 returning the wrong version number on Windows 10.
1120 The locale categories C<LC_SYNTAX> and C<LC_TOD> are now recognized.
1121 Perl doesn't do anything with these, except it now allows you to specify
1122 them. They are included in C<LC_ALL>.
1126 =head1 Internal Changes
1132 Corrected handling of double and long double parameters for perl's
1133 implementation of formatted output for C<-Dusequadmath> builds.
1135 This applies to C<PerlIO_printf()>, C<croak()>, C<warn()>, C<sv_catpvf()> and
1138 Previously in C<quadmath> builds, code like:
1140 PerlIO_printf(PerlIO_stderr(), "%g", somedouble);
1144 PerlIO_printf(PerlIO_stderr(), "%Lg", somelongdouble);
1146 would erroneously throw an exception "panic: quadmath invalid format
1147 ...", since the code added for quadmath builds assumed C<NV>s were the
1148 only floating point format passed into these functions.
1150 This code would also process the standard C long double specifier C<L>
1151 as if it expected an C<NV> (C<__float128> for quadmath builds),
1152 resulting in undefined behaviour.
1154 These functions now correctly accept doubles, long doubles and NVs.
1158 Previously the right operand of bitwise shift operators (shift amount)
1159 was implicitly cast from IV to int, but it might lead wrong results
1160 if IV does not fit in int.
1162 And also, shifting INT_MIN bits used to yield the shiftee unchanged
1163 (treated as 0-bit shift instead of negative shift).
1167 A set of C<cop_hints_exists_{pv,pvn,pvs,sv}> functions was added,
1168 to support checking for the existence of keys in the hints hash of a
1169 specific cop without needing to create a mortal copy of said value.
1173 An aid has been added for using the C<DEBUG> macros when debugging XS or
1174 C code. The comments in F<perl.h> describe C<DEBUG_PRE_STMTS> and
1175 C<DEBUG_POST_STMTS>. which you can C<#define> to do things like save and
1176 restore C<errno>, in case the C<DEBUG> calls are interfering with that,
1177 or to display timestamps, or which thread it's coming from, or the
1178 location of the call, or whatever. You can make a quick hack to help
1179 you track something down without having to edit individual C<DEBUG>
1184 Make C<REFCOUNTED_HE_EXISTS> available outside of core
1188 All C<SvTRUE>-ish functions now evaluate their arguments exactly once.
1189 In 5.32, plain L<perlapi/C<SvTRUE>> was changed to do that; now the rest
1194 Unicode is now a first class citizen when considering the pattern /A*B/ where
1195 A and B are arbitrary. The pattern matching code tries to make a tight loop
1196 to match the span of A's. The logic of this was now really updated with
1201 The L<re> module has a new function C<optimization>, which can return a hashref
1202 of optimization data discovered about a compiled regexp.
1206 The C<PERL_GLOBAL_STRUCT> compilation option has been removed, and
1207 with it the need or the C<dVAR> macro. C<dVAR> remains defined as a
1208 no-op outside C<PERL_CORE> for backwards compatiblity with XS modules.
1212 A new savestack type C<SAVEt_HINTS_HH> has been added, which neatens the
1213 previous behaviour of C<SAVEt_HINTS>. On previous versions the types and
1214 values pushed to the save stack would depend on whether the hints included the
1215 C<HINT_LOCALIZE_HH> bit, which complicates external code that inspects the
1216 save stack. The new version uses a different savestack type to indicate the
1221 A new API function L<perlapi/av_count> has been added which gives a
1222 clearly named way to find how many elements are in an array.
1226 =head1 Selected Bug Fixes
1232 Setting C<%ENV> now properly handles upgraded strings in the key. Previously
1233 Perl sent the SV's internal PV directly to the OS; now it will handle keys
1234 as it has handled values since 5.18: attempt to downgrade the string first;
1235 if that fails then warn and use the utf8 form.
1239 Fix a memory leak in F<regcomp.c> (L<GH #18604|https://github.com/Perl/perl5/issues/18604>)
1241 =item * pack/unpack format 'D' now works on all systems that could support it
1243 Previously if C<NV == long double>, now it is supported on all platforms that
1244 have long doubles. In particular that means it is now also supported on
1249 Skip trying to constant fold an incomplete op tree
1250 [L<GH #18380|https://github.com/Perl/perl5/issues/18380>]
1252 Constant folding of chained comparison op trees could fail under certain
1253 conditions, causing perl to crash. As a quick fix, constant folding is
1254 now skipped for such op trees. This also addresses
1255 [L<GH #17917|https://github.com/Perl/perl5/issues/17917>].
1259 C<%g> formatting broken on Ubuntu-18.04, C<NVSIZE == 8>
1260 [L<GH #18170|https://github.com/Perl/perl5/issues/18170>]
1262 Buggy libc implementations of the C<gcvt> and C<qgcvt> functions
1263 caused C<(s)printf> to incorrectly truncate C<%g> formatted numbers.
1264 A new Configure probe now checks for this, with the result that the libc
1265 C<sprintf> will be used in place of C<gcvt> and C<qgcvt>.
1267 Tests added as part of this fix also revealed related problems in
1268 some Windows builds. The makefiles for MINGW builds on Windows have
1269 thus been adjusted to use C<USE_MINGW_ANSI_STDIO> by default, ensuring
1270 that they also provide correct C<(s)printf> formatting of numbers.
1274 F<op.c>: croak on C<my $_> when C<use utf8> is in effect
1275 [L<GH #18449|https://github.com/Perl/perl5/issues/18449>]
1277 The lexical topic feature experiment was removed in Perl v5.24 and
1278 declaring C<my $_> became a compile time error. However, it was previously
1279 still possible to make this declaration if C<use utf8> was in effect.
1283 F<regexec.c>: Fix assertion failure
1284 [L<GH #18451|https://github.com/Perl/perl5/issues/18451>]
1286 Fuzzing triggered an assertion failure in the regexp engine when too many
1287 characters were copied into a buffer.
1291 L<semctl()|perlfunc/semctl>, L<msgctl()|perlfunc/msgctl>, and
1292 L<shmctl()|perlfunc/shmctl> now properly reset the UTF-8 flag on the
1293 C<ARG> parameter if it's modified for C<IPC_STAT> or C<GETALL>
1298 C<semctl()>, C<msgctl()>, and C<shmctl()> now attempt to downgrade the C<ARG>
1299 parameter if its value is being used as input to C<IPC_SET> or
1300 C<SETALL> calls. A failed downgrade will thrown an exception.
1304 In cases where C<semctl()>, C<msgctl()> or C<shmctl()> would treat the C<ARG>
1305 parameter as a pointer, an undefined value no longer generates a
1306 warning. In most such calls the pointer isn't used anyway and this
1307 allows you to supply C<undef> for a value not used by the underlying
1312 L<semop()|perlfunc/semop> now downgrades the C<OPSTRING> parameter,
1313 L<msgsnd()|perlfunc/msgsnd> now downgrades the C<MSG> parameter and
1314 L<shmwrite|perlfunc/shmwrite> now downgrades the C<STRING> parameter
1315 to treat them as bytes. Previously they would be left upgraded,
1316 providing a corrupted structure to the underlying function call.
1320 L<msgrcv()|perlfunc/msgrcv> now properly resets the UTF-8 flag the
1321 C<VAR> parameter when it is modified. Previusly the UTF-8 flag could
1322 be left on, resulting in a possibly corrupt result in C<VAR>.
1326 Magic is now called correctly for stacked file test operators. [L<GH #18293|https://github.com/Perl/perl5/issues/18293>]
1330 The C<@ary = split(...)> optimization no longer switches in the target
1331 array as the value stack. [L<GH #18232|https://github.com/Perl/perl5/issues/18232>] Also see discussion at
1332 L<https://github.com/Perl/perl5/pull/18014#issuecomment-671299506>.
1336 Fixed a bug in which some regexps with recursive subpatterns matched
1339 [L<GH #18096|https://github.com/Perl/perl5/issues/18096>]
1343 On Win32, C<waitpid(-1, WNOHANG)> could sometimes have a very large
1344 timeout. L<GH #16529|https://github.com/Perl/perl5/issues/16529>
1348 C<MARK> and hence C<items> are now correctly initialized in C<BOOT> XSUBs.
1352 Some list assignments involving C<undef> on the left-hand side were
1353 over-optimized and produced incorrect results. L<GH #16685|https://github.com/Perl/perl5/issues/16685>, L<GH #17816|https://github.com/Perl/perl5/issues/17816>
1357 =head1 Known Problems
1361 =head1 Errata From Previous Releases
1367 Kent Fredric (KENTNL) passed away in February 2021. A native of New Zealand
1368 and a self-described "huge geek," Kent was the author or maintainer of 178
1369 CPAN distributions, the Perl maintainer for the Gentoo Linux distribution and
1370 a contributor to the Perl core distribution. He is mourned by his family,
1371 friends and open source software communities worldwide.
1373 =head1 Acknowledgements
1375 Perl 5.34.0 represents approximately 10 months of development since Perl
1376 5.32.0 and contains approximately 280,000 lines of changes across 2,100
1377 files from 77 authors.
1379 Excluding auto-generated files, documentation and release tools, there were
1380 approximately 150,000 lines of changes to 1,300 .pm, .t, .c and .h files.
1382 Perl continues to flourish into its fourth decade thanks to a vibrant
1383 community of users and developers. The following people are known to have
1384 contributed the improvements that became Perl 5.34.0:
1386 Aaron Crane, Adam Hartley, Andy Dougherty, Ben Cornett, Branislav
1387 Zahradník, brian d foy, Chris 'BinGOs' Williams, Christian Walde
1388 (Mithaldu), Craig A. Berry, Dagfinn Ilmari Mannsåker, Dan Book, Daniel
1389 Böhmer, Daniel Laügt, Dan Kogai, David Cantrell, David Mitchell, Dominic
1390 Hamon, E. Choroba, Ed J, Eric Herman, Eric Lindblad, Eugene Alvin Villar,
1391 Felipe Gasper, Giovanni Tataranni, Graham Knop, Graham Ollis, Hauke D,
1392 H.Merijn Brand, Hugo van der Sanden, Ichinose Shogo, Ivan Baidakou, Jae
1393 Bradley, James E Keenan, Jason McIntosh, jkahrman, John Karr, John Lightsey,
1394 Kang-min Liu, Karen Etheridge, Karl Williamson, Keith Thompson, Leon
1395 Timmermans, Marc Reisner, Marcus Holland-Moritz, Max Maischein, Michael G
1396 Schwern, Nicholas Clark, Nicolas R., Paul Evans, Petr Písař, raiph, Renee
1397 Baecker, Ricardo Signes, Richard Leach, Romano, Ryan Voots, Samanta Navarro,
1398 Samuel Thibault, Sawyer X, Scott Baker, Sergey Poznyakoff, Sevan Janiyan,
1399 Shlomi Fish, Sisyphus, Sizhe Zhao, Steve Hay, TAKAI Kousuke, Thibault
1400 Duponchelle, Todd Rinaldo, Tomasz Konojacki, Tom Hukins, Tom Stellard, Tony
1401 Cook, vividsnow, Yves Orton, Zakariyya Mughal, Михаил
1404 The list above is almost certainly incomplete as it is automatically
1405 generated from version control history. In particular, it does not include
1406 the names of the (very much appreciated) contributors who reported issues to
1407 the Perl bug tracker.
1409 Many of the changes included in this version originated in the CPAN modules
1410 included in Perl's core. We're grateful to the entire CPAN community for
1411 helping Perl to flourish.
1413 For a more complete list of all of Perl's historical contributors, please
1414 see the F<AUTHORS> file in the Perl source distribution.
1416 =head1 Reporting Bugs
1418 If you find what you think is a bug, you might check the perl bug database
1419 at L<https://github.com/Perl/perl5/issues>. There may also be information at
1420 L<http://www.perl.org/>, the Perl Home Page.
1422 If you believe you have an unreported bug, please open an issue at
1423 L<https://github.com/Perl/perl5/issues>. Be sure to trim your bug down to a
1424 tiny but sufficient test case.
1426 If the bug you are reporting has security implications which make it
1427 inappropriate to send to a public issue tracker, then see
1428 L<perlsec/SECURITY VULNERABILITY CONTACT INFORMATION>
1429 for details of how to report the issue.
1433 If you wish to thank the Perl 5 Porters for the work we had done in Perl 5,
1434 you can do so by running the C<perlthanks> program:
1438 This will send an email to the Perl 5 Porters list with your show of thanks.
1442 The F<Changes> file for an explanation of how to view exhaustive details on
1445 The F<INSTALL> file for how to build Perl.
1447 The F<README> file for general stuff.
1449 The F<Artistic> and F<Copying> files for copyright information.