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 modules 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 2.178.
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 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.
580 Simplify the C<split()> documentation by removing the C<join()>s from the examples
591 Efforts continue in improving the presentation of this document, and to
592 document more API elements.
596 =head3 L<perlcommunity>
602 The freenode IRC URL has been updated.
606 =head3 L<perldebguts>
612 Corrected the description of the scalar C<< ${"_<$filename"} >>
623 Now documents additional examples of "not imported" warnings.
633 The Perl FAQ was updated to CPAN version 5.20201107 with minor
644 Document that caller() does not see try{} blocks
648 L<my()|perlfunc/my> and L<state()|perlfunc/state> now explicitly warn
649 the reader that lexical variables should typically not be redeclared
650 within the same scope or statement.
651 L<[GH #18389]|https://github.com/Perl/perl5/issues/18389>
655 The L<localtime|perlfunc/localtime> entry has been improved and now
656 also states that the result of the function is always in English.
660 L<msgsnd()|perlfunc/msgsnd> documented a length field included in the
661 packed C<MSG> parameter to msgsnd(), but there was no such field.
662 C<MSG> contains only the type and the message content.
666 Better explanation of what happens when C<sleep> is called with a zero or
677 document how to create a remote-tracking branch for every PR
681 document how to get a PR as a local branch
691 L<perlguts> now explains in greater detail the need to consult SvUTF8
692 when calling SvPV (or variants). A new "How do I pass a Perl string to a C
693 library?" section in the same document discusses when to use which style of
694 macro to read an SV's string value.
698 Corrected C<my_rpeep> example in perlguts.
702 A section has been added on the formatted printing of special sizes.
712 The C<< <> >> and C<<< <<>> >>> operators are commonly referred to as
713 the diamond and double diamond operators respectively, but that wasn't
714 mentioned previously in their documentation.
718 Document range op behavior change.
722 =head3 L<perlpacktut>
728 Incorrect variables used in an example have been fixed.
738 Document that caller() does not see try{} blocks
742 A new example shows how a lexical C<my> variable can be declared
743 during the initialization of a C<for> loop.
753 Fix description of what Perl does with unencoded strings
759 The following additions or changes have been made to diagnostic output,
760 including warnings and fatal error messages. For the complete list of
761 diagnostic messages, see L<perldiag>.
763 =head2 New Diagnostics
771 L<Bareword filehandle "%s" not allowed under 'no feature "bareword_filehandles"'|perldiag/"Bareword filehandle "%s" not allowed under 'no feature "bareword_filehandles"'">
773 This accompanies the new L<bareword_filehandles|feature/"The 'bareword_filehandles' feature."> feature.
777 L<Multidimensional hash lookup is disabled|perldiag/"Multidimensional hash lookup is disabled">
779 This accompanies the new L<multidimensional|feature/"The 'multidimensional' feature"> feature.
789 L<Wide character in setenv key (encoding to utf8)|perldiag/"Wide character in %s">
791 Attempts to put wide characters into environment variable keys via C<%ENV> now
792 provoke this warning.
796 =head2 Changes to Existing Diagnostics
802 L<Error %s in expansion of %s|perldiag/"Error %s in expansion of %s">
804 An error was encountered in handling a user-defined property
805 (L<perlunicode/User-Defined Character Properties>). These are
806 programmer written subroutines, hence subject to errors that may
807 prevent them from compiling or running.
811 L<Infinite recursion in user-defined property|perldiag/"Infinite recursion in user-defined property">
813 A user-defined property (L<perlunicode/User-Defined Character Properties>)
814 can depend on the definitions of other user-defined
815 properties. If the chain of dependencies leads back to this property,
816 infinite recursion would occur, were it not for the check that raised
821 L<Timeout waiting for another thread to define \p{%s}|perldiag/"Timeout waiting for another thread to define \p{%s}">
823 The first time a user-defined property
824 (L<perlunicode/User-Defined Character Properties>) is used, its
825 definition is looked up and converted into an internal form for more
826 efficient handling in subsequent uses. There could be a race if two or
827 more threads tried to do this processing nearly simultaneously.
831 L<Unknown user-defined property name \p{%s}|perldiag/"Unknown user-defined property name \p{%s}">
833 You specified to use a property within the C<\p{...}> which was a
834 syntactically valid user-defined property, but no definition was found
839 L<Too few arguments for subroutine '%s' (got %d; expected %d)|perldiag/"Too few arguments for subroutine '%s' (got %d; expected %d)">
841 Subroutine argument-count mismatch errors now include the number of
842 given and expected arguments.
846 L<Too many arguments for subroutine '%s' (got %d; expected %d)|perldiag/"Too many arguments for subroutine '%s' (got %d; expected %d)">
848 Subroutine argument-count mismatch errors now include the number of
849 given and expected arguments.
853 L<Lost precision when %s %f by 1|perldiag/"Lost precision when %s %f by 1">
855 This warning was only issued for positive too-large values when
856 incrementing, and only for negative ones when decrementing.
857 It is now issued for both positive or negative too-large values.
858 [L<GH #18333|https://github.com/Perl/perl5/issues/18333>]
862 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/">
864 This error was incorrectly produced in some cases involving nested
865 lookarounds. This has been fixed. [L<GH #18123|https://github.com/Perl/perl5/issues/18123>]
869 L<Use of uninitialized value%s|perldiag/"Use of uninitialized value%s">
871 This warning may now include the array or hash index when the
872 uninitialized value is the result of an element not found. This will
873 only happen if the index is a simple non-magical variable.
877 =head1 Utility Changes
879 =head2 L<perl5db.pl> (the debugger)
883 =item * New option: C<HistItemMinLength>
885 This option controls the minimum length a command must be to get stored in
886 history. Traditionally, this has been fixed at 2. Changes to the debugger
887 are often perilous, and new bugs should be reported so the debugger can be
890 =item * Fix to C<i> and C<l> commands
892 The C<i $var> and C<l $var> commands work again with lexical variables.
896 =head1 Configuration and Compilation
902 Prevented incpath to spill into libpth
906 Use realpath if available.
910 This might catch more duplicate paths.
914 Only include real existing paths.
918 Filter inc paths out of libpth.
920 =item * stadtx hash support has been removed
922 stadtx support has been entirely removed. Previously, it could be requested
923 with PERL_HASH_FUNC_STADTX, and was default in 64-bit builds. It has been
924 replaced with SipHash. SipHash has been more rigorously reviewed than stadtx.
928 A new probe checks for buggy libc implementations of the C<gcvt>/C<qgcvt>
930 [L<GH #18170|https://github.com/Perl/perl5/issues/18170>]
932 =item * C<-Dusedefaultstrict>
934 EXPERIMENTAL: Perl can now be built with L<strict> on by default (using the
935 configuration option C<-Dusedefaultstrict>.
937 These strict defaults do not apply when C<perl> is run via C<-e> or C<-E>.
939 This setting provides a diagnostic mechanism for perl developers for
940 development and is intended for development purposes only and is thus turned
945 The minimum supported Bison version is now 2.4, and the maxiumm is 3.7.
949 Newer 64-bit versions of the Intel C/C++ compiler are now recognised
950 and have the correct flags set.
954 Added the F<Configure> option B<-Dusedefaultstrict> to enable strict by default
955 in perl programs when not invoked with B<-e> or B<-E>. This is a diagnostic
956 tool for development.
960 We now trap SIGBUS when F<Configure> checks for C<va_copy>.
962 On several systems the attempt to determine if we need C<va_copy> or similar
963 results in a SIGBUS instead of the expected SIGSEGV, which previously caused a
966 [L<GH #18148|https://github.com/Perl/perl5/issues/18148>]
972 Tests were added and changed to reflect the other additions and
973 changes in this release. Furthermore, these significant changes were
980 Split Config-dependent tests in t/opbasic/arith.t to t/op/arith2.t
984 F<t/re/opt.t> was added, providing a test harness for regexp optimization.
985 [L<GH #18213|https://github.com/Perl/perl5/pull/18213>]
989 A workaround for CPAN distributions needing dot in C<@INC> has been removed
990 [L<GH #18394|https://github.com/Perl/perl5/pull/18394>].
991 All distributions that previously required the workaround have now been
996 When testing in parallel on many-core platforms, you can now cause the
997 test suite to finish somewhat earlier, but with less logical ordering of
998 the tests, by setting
1000 PERL_TEST_HARNESS_ASAP=1
1002 while running the test suite.
1006 =head1 Platform Support
1008 =head2 New Platforms
1014 Allow building Perl on i386 9front systems (fork of plan9).
1018 =head2 Updated Platforms
1024 Improve support for Plan9 on i386 platforms.
1026 =item MacOS (Darwin)
1028 The hints file for darwin has been updated to handle future MacOS versions
1029 beyond 10. L<GH #17946|https://github.com/Perl/perl5/issues/17946>
1033 =head2 Discontinued Platforms
1039 Support code relating to Symbian has been removed. Symbian was an
1040 operating system for mobile devices. The port was last updated in July
1041 2009, and the platform itself in October 2012.
1045 =head2 Platform-Specific Notes
1051 Tests were updated to workaround DragonFlyBSD bugs in L<tc*()
1052 functions|https://bugs.dragonflybsd.org/issues/3252> and L<ctime
1053 updates|https://bugs.dragonflybsd.org/issues/3251>.
1057 A number of system libraries no longer exist as actual files on Big Sur,
1058 even though C<dlopen> will pretend they do, so now we fall back to C<dlopen>
1059 if a library file can not be found.
1060 [L<GH #18407|https://github.com/Perl/perl5/issues/18407>]
1064 Reading non-ASCII characters from the console when its codepage was set to
1065 65001 (UTF-8) was broken due to a bug in Windows. A workaround for this
1066 problem has been implemented.
1067 [L<GH #18701|https://github.com/Perl/perl5/issues/18701>]
1069 Building with mingw.org compilers (version 3.4.5 or later) using mingw runtime
1070 versions < 3.22 now works again. This was broken in Perl 5.31.4.
1072 Building with mingw.org compilers (version 3.4.5 or later) using mingw runtime
1073 versions >= 3.21 now works (for compilers up to version 5.3.0).
1075 Makefile.mk, and thus support for dmake, has been removed. It is still possible
1076 to build Perl on Windows using nmake (Makefile) and GNU make (GNUmakefile).
1077 [L<GH #18511|https://github.com/Perl/perl5/pull/18511>]
1079 perl can now be built with C<USE_QUADMATH> on MS Windows using
1080 (32-bit and 64-bit) mingw-w64 ports of gcc.
1081 [L<GH #18465|https://github.com/Perl/perl5/pull/18465>]
1083 The F<pl2bat.pl> utility now needs to C<use ExtUtils::PL2Bat>. This could
1084 cause failures in parallel builds.
1086 Windows now supports L<symlink()|perlfunc/symlink> and
1087 L<readlink()|perlfunc/readlink>, and L<lstat()|perlfunc/lstat> is no
1088 longer an alias for L<stat()|perlfunc/stat>.
1089 L<[GH #18005]|https://github.com/Perl/perl5/issues/18005>.
1091 Unlike POSIX systems, creating a symbolic link on Windows requires
1092 either elevated privileges or Windows 10 1703 or later with Developer
1095 stat(), including C<stat FILEHANDLE>, and lstat() now uses our own
1096 implementation that populates the device C<dev> and inode numbers
1097 C<ino> returned rather than always returning zero. The number of
1098 links C<nlink> field is now always populated.
1100 L<< C<${^WIN32_SLOPPY_STAT}> |perlvar/${^WIN32_SLOPPY_STAT} >> previously
1101 controlled whether the C<nlink> field was populated requiring a
1102 separate Windows API call to fetch, since nlink and the other
1103 information required for stat() is now retrieved in a single API call.
1105 The C<-r> and C<-w> operators now return true for the C<STDIN>,
1106 C<STDOUT> and C<STDERR> handles. Unfortunately it still won't return
1107 true for duplicates of those handles.
1108 L<[GH #8502]|https://github.com/Perl/perl5/issues/8502>.
1110 The times returned by stat() and lstat() are no longer incorrect
1111 across Daylight Savings Time adjustments.
1112 L<[GH #6080]|https://github.com/Perl/perl5/issues/6080>.
1114 C<-x> on a filehandle should now match C<-x> on the corresponding
1115 filename on Vista or later.
1116 L<[GH #4145]|https://github.com/Perl/perl5/issues/4145>.
1118 C<-e '"'> no longer incorrectly returns true.
1119 L<[GH #12431]|https://github.com/Perl/perl5/issues/12431>.
1121 The same manifest is now used for Visual C++ and gcc builds.
1123 Previously, MSVC builds were using the B</manifestdependency> flag instead of
1124 embedding F<perlexe.manifest>, which caused issues such as C<GetVersionEx()>
1125 returning the wrong version number on Windows 10.
1129 The locale categories C<LC_SYNTAX> and C<LC_TOD> are now recognized.
1130 Perl doesn't do anything with these, except it now allows you to specify
1131 them. They are included in C<LC_ALL>.
1135 =head1 Internal Changes
1141 Corrected handling of double and long double parameters for perl's
1142 implementation of formatted output for C<-Dusequadmath> builds.
1144 This applies to PerlIO_printf(), croak(), warn(), sv_catpvf() and
1147 Previously in C<quadmath> builds, code like:
1149 PerlIO_printf(PerlIO_stderr(), "%g", somedouble);
1153 PerlIO_printf(PerlIO_stderr(), "%Lg", somelongdouble);
1155 would erroneously throw an exception "panic: quadmath invalid format
1156 ...", since the code added for quadmath builds assumed C<NV>s were the
1157 only floating point format passed into these functions.
1159 This code would also process the standard C long double specifier C<L>
1160 as if it expected an C<NV> (C<__float128> for quadmath builds),
1161 resulting in undefined behaviour.
1163 These functions now correctly accept doubles, long doubles and NVs.
1167 Previously the right operand of bitwise shift operators (shift amount)
1168 was implicitly cast from IV to int, but it might lead wrong results
1169 if IV does not fit in int.
1171 And also, shifting INT_MIN bits used to yield the shiftee unchanged
1172 (treated as 0-bit shift instead of negative shift).
1176 A set of cop_hints_exists_{pv,pvn,pvs,sv} functions was added, to support checking
1177 for the existence of keys in the hints hash of a specific cop without needing to
1178 create a mortal copy of said value.
1182 An aid has been added for using the C<DEBUG> macros when debugging XS or
1183 C code. The comments in F<perl.h> describe C<DEBUG_PRE_STMTS> and
1184 C<DEBUG_POST_STMTS>. which you can C<#define> to do things like save and
1185 restore C<errno>, in case the C<DEBUG> calls are interfering with that,
1186 or to display timestamps, or which thread it's coming from, or the
1187 location of the call, or whatever. You can make a quick hack to help
1188 you track something down without having to edit individual C<DEBUG>
1193 Make REFCOUNTED_HE_EXISTS available outside of core
1197 All C<SvTRUE>-ish functions now evaluate their arguments exactly once.
1198 In 5.32, plain L<perlapi/C<SvTRUE>> was changed to do that; now the rest
1203 Unicode is now a first class citizen when considering the pattern /A*B/ where
1204 A and B are arbitrary. The pattern matching code tries to make a tight loop
1205 to match the span of A's. The logic of this was now really updated with
1210 The L<re> module has a new function C<optimization>, which can return a hashref
1211 of optimization data discovered about a compiled regexp.
1215 The C<PERL_GLOBAL_STRUCT> compilation option has been removed, and
1216 with it the need or the C<dVAR> macro. C<dVAR> remains defined as a
1217 no-op outside C<PERL_CORE> for backwards compatiblity with XS modules.
1221 A new savestack type C<SAVEt_HINTS_HH> has been added, which neatens the
1222 previous behaviour of C<SAVEt_HINTS>. On previous versions the types and
1223 values pushed to the save stack would depend on whether the hints included the
1224 C<HINT_LOCALIZE_HH> bit, which complicates external code that inspects the
1225 save stack. The new version uses a different savestack type to indicate the
1230 A new API function L<perlapi/av_count> has been added which gives a
1231 clearly named way to find how many elements are in an array.
1235 =head1 Selected Bug Fixes
1241 Setting %ENV now properly handles upgraded strings in the key. Previously
1242 Perl sent the SV's internal PV directly to the OS; now it will handle keys
1243 as it has handled values since 5.18: attempt to downgrade the string first;
1244 if that fails then warn and use the utf8 form.
1248 Fix a memory leak in regcomp.c (L<GH #18604|https://github.com/Perl/perl5/issues/18604>)
1250 =item * pack/unpack format 'D' now works on all systems that could support it
1252 Previously if C<NV == long double>, now it is supported on all platforms that
1253 have long doubles. In particular that means it is now also supported on
1258 Skip trying to constant fold an incomplete op tree
1259 [L<GH #18380|https://github.com/Perl/perl5/issues/18380>]
1261 Constant folding of chained comparison op trees could fail under certain
1262 conditions, causing perl to crash. As a quick fix, constant folding is
1263 now skipped for such op trees. This also addresses
1264 [L<GH #17917|https://github.com/Perl/perl5/issues/17917>].
1268 %g formatting broken on Ubuntu-18.04, NVSIZE == 8
1269 [L<GH #18170|https://github.com/Perl/perl5/issues/18170>]
1271 Buggy libc implementations of the C<gcvt> and C<qgcvt> functions
1272 caused C<(s)printf> to incorrectly truncate C<%g> formatted numbers.
1273 A new Configure probe now checks for this, with the result that the libc
1274 C<sprintf> will be used in place of C<gcvt> and C<qgcvt>.
1276 Tests added as part of this fix also revealed related problems in
1277 some Windows builds. The makefiles for MINGW builds on Windows have
1278 thus been adjusted to use USE_MINGW_ANSI_STDIO by default, ensuring
1279 that they also provide correct C<(s)printf> formatting of numbers.
1283 op.c: croak on "my $_" when "use utf8" is in effect
1284 [L<GH #18449|https://github.com/Perl/perl5/issues/18449>]
1286 The lexical topic feature experiment was removed in Perl v5.24 and
1287 declaring C<my $_> became a compile time error. However, it was previously
1288 still possible to make this declaration if C<use utf8> was in effect.
1292 regexec.c: Fix assertion failure
1293 [L<GH #18451|https://github.com/Perl/perl5/issues/18451>]
1295 Fuzzing triggered an assertion failure in the regexp engine when too many
1296 characters were copied into a buffer.
1300 L<semctl()|perlfunc/semctl>, L<msgctl()|perlfunc/msgctl>, and
1301 L<shmctl()|perlfunc/shmctl> now properly reset the UTF-8 flag on the
1302 C<ARG> parameter if it's modified for C<IPC_STAT> or C<GETALL>
1307 semctl(), msgctl(), and shmctl() now attempt to downgrade the C<ARG>
1308 parameter if its value is being used as input to C<IPC_SET> or
1309 C<SETALL> calls. A failed downgrade will thrown an exception.
1313 In cases where semctl(), msgctl() or shmctl() would treat the C<ARG>
1314 parameter as a pointer, an undefined value no longer generates a
1315 warning. In most such calls the pointer isn't used anyway and this
1316 allows you to supply C<undef> for a value not used by the underlying
1321 L<semop()|perlfunc/semop> now downgrades the C<OPSTRING> parameter,
1322 L<msgsnd()|perlfunc/msgsnd> now downgrades the C<MSG> parameter and
1323 L<shmwrite|perlfunc/shmwrite> now downgrades the C<STRING> parameter
1324 to treat them as bytes. Previously they would be left upgraded,
1325 providing a corrupted structure to the underlying function call.
1329 L<msgrcv()|perlfunc/msgrcv> now properly resets the UTF-8 flag the
1330 C<VAR> parameter when it is modified. Previusly the UTF-8 flag could
1331 be left on, resulting in a possibly corrupt result in C<VAR>.
1335 Magic is now called correctly for stacked file test operators. [L<GH #18293|https://github.com/Perl/perl5/issues/18293>]
1339 The C<@ary = split(...)> optimization no longer switches in the target
1340 array as the value stack. [L<GH #18232|https://github.com/Perl/perl5/issues/18232>] Also see discussion at
1341 L<https://github.com/Perl/perl5/pull/18014#issuecomment-671299506>.
1345 Fixed a bug in which some regexps with recursive subpatterns matched
1348 [L<GH #18096|https://github.com/Perl/perl5/issues/18096>]
1352 On Win32, C<waitpid(-1, WNOHANG)> could sometimes have a very large
1353 timeout. L<GH #16529|https://github.com/Perl/perl5/issues/16529>
1357 C<MARK> and hence C<items> are now correctly initialized in BOOT XSUBs.
1361 Some list assignments involving C<undef> on the left-hand side were
1362 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>
1366 =head1 Known Problems
1370 =head1 Errata From Previous Releases
1376 Kent Fredric (KENTNL) passed away in February 2021. A native of New Zealand
1377 and a self-described "huge geek," Kent was the author or maintainer of 178
1378 CPAN distributions, the Perl maintainer for the Gentoo Linux distribution and
1379 a contributor to the Perl core distribution. He is mourned by his family,
1380 friends and open source software communities worldwide.
1382 =head1 Acknowledgements
1384 Perl 5.34.0 represents approximately 10 months of development since Perl
1385 5.32.0 and contains approximately 280,000 lines of changes across 2,100
1386 files from 77 authors.
1388 Excluding auto-generated files, documentation and release tools, there were
1389 approximately 150,000 lines of changes to 1,300 .pm, .t, .c and .h files.
1391 Perl continues to flourish into its fourth decade thanks to a vibrant
1392 community of users and developers. The following people are known to have
1393 contributed the improvements that became Perl 5.34.0:
1395 Aaron Crane, Adam Hartley, Andy Dougherty, Ben Cornett, Branislav
1396 Zahradník, brian d foy, Chris 'BinGOs' Williams, Christian Walde
1397 (Mithaldu), Craig A. Berry, Dagfinn Ilmari Mannsåker, Dan Book, Daniel
1398 Böhmer, Daniel Laügt, Dan Kogai, David Cantrell, David Mitchell, Dominic
1399 Hamon, E. Choroba, Ed J, Eric Herman, Eric Lindblad, Eugene Alvin Villar,
1400 Felipe Gasper, Giovanni Tataranni, Graham Knop, Graham Ollis, Hauke D,
1401 H.Merijn Brand, Hugo van der Sanden, Ichinose Shogo, Ivan Baidakou, Jae
1402 Bradley, James E Keenan, Jason McIntosh, jkahrman, John Karr, John Lightsey,
1403 Kang-min Liu, Karen Etheridge, Karl Williamson, Keith Thompson, Leon
1404 Timmermans, Marc Reisner, Marcus Holland-Moritz, Max Maischein, Michael G
1405 Schwern, Nicholas Clark, Nicolas R., Paul Evans, Petr Písař, raiph, Renee
1406 Baecker, Ricardo Signes, Richard Leach, Romano, Ryan Voots, Samanta Navarro,
1407 Samuel Thibault, Sawyer X, Scott Baker, Sergey Poznyakoff, Sevan Janiyan,
1408 Shlomi Fish, Sisyphus, Sizhe Zhao, Steve Hay, TAKAI Kousuke, Thibault
1409 Duponchelle, Todd Rinaldo, Tomasz Konojacki, Tom Hukins, Tom Stellard, Tony
1410 Cook, vividsnow, Yves Orton, Zakariyya Mughal, Михаил
1413 The list above is almost certainly incomplete as it is automatically
1414 generated from version control history. In particular, it does not include
1415 the names of the (very much appreciated) contributors who reported issues to
1416 the Perl bug tracker.
1418 Many of the changes included in this version originated in the CPAN modules
1419 included in Perl's core. We're grateful to the entire CPAN community for
1420 helping Perl to flourish.
1422 For a more complete list of all of Perl's historical contributors, please
1423 see the F<AUTHORS> file in the Perl source distribution.
1425 =head1 Reporting Bugs
1427 If you find what you think is a bug, you might check the perl bug database
1428 at L<https://github.com/Perl/perl5/issues>. There may also be information at
1429 L<http://www.perl.org/>, the Perl Home Page.
1431 If you believe you have an unreported bug, please open an issue at
1432 L<https://github.com/Perl/perl5/issues>. Be sure to trim your bug down to a
1433 tiny but sufficient test case.
1435 If the bug you are reporting has security implications which make it
1436 inappropriate to send to a public issue tracker, then see
1437 L<perlsec/SECURITY VULNERABILITY CONTACT INFORMATION>
1438 for details of how to report the issue.
1442 If you wish to thank the Perl 5 Porters for the work we had done in Perl 5,
1443 you can do so by running the C<perlthanks> program:
1447 This will send an email to the Perl 5 Porters list with your show of thanks.
1451 The F<Changes> file for an explanation of how to view exhaustive details on
1454 The F<INSTALL> file for how to build Perl.
1456 The F<README> file for general stuff.
1458 The F<Artistic> and F<Copying> files for copyright information.