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diff --git a/pod/perl5340delta.pod b/pod/perl5340delta.pod new file mode 100644 index 0000000000..23235fb634 --- /dev/null +++ b/pod/perl5340delta.pod @@ -0,0 +1,1456 @@ +=encoding utf8 + +=head1 NAME + +perl5340delta - what is new for perl v5.34.0 + +=head1 DESCRIPTION + +This document describes differences between the 5.32.0 release and the 5.34.0 +release. + +If you are upgrading from an earlier release such as 5.30.0, first read +L<perl5320delta>, which describes differences between 5.30.0 and 5.32.0. + +=head1 Core Enhancements + +=head2 Experimental Try/Catch Syntax + +An initial experimental attempt at providing C<try>/C<catch> notation has +been added. + + use feature 'try'; + + try { + a_function(); + } + catch ($e) { + warn "An error occurred: $e"; + } + +For more information, see L<perlsyn/"Try Catch Exception Handling">. + +=head2 C<qr/{,n}/> is now accepted + +An empty lower bound is now accepted for regular expression quantifiers, +like C<{,3}>. + +=head2 Blanks freely allowed within but adjacent to curly braces + +(in double-quotish contexts and regular expression patterns) + +This means you can write things like S<C<\x{ FFFC }>> if you like. This +applies to all such constructs, namely C<\b{}>, C<\g{}>, C<\k{}>, +C<\N{}>, C<\o{}>, and C<\x{}>; as well as the regular expression +quantifier C<{I<m>,I<n>}>. C<\p{}> and C<\P{}> retain their +already-existing, even looser, rules mandated by the Unicode standard +(see L<perluniprops/Properties accessible through \p{} and \P{}>). + +This ability is in effect regardless of the presence of the C</x> +regular expression pattern modifier. + +Additionally, the comma in a regular expression braced quantifier may +have blanks (tabs or spaces) before and/or after the comma, like +S<C<qr/a{ 5, 7 }/>>. + +=head2 New octal syntax C<0oI<ddddd>> + +It is now possible to specify octal literals with C<0o> prefixes, +as in C<0o123_456>, parallel to the existing construct to specify +hexadecimal literal C<0xI<ddddd>> and binary literal C<0bI<ddddd>>. +Also, the builtin C<oct()> function now accepts this new syntax. + +See L<perldata/Scalar value constructors> and L<perlfunc/oct EXPR>. + +=head1 Performance Enhancements + +=over 4 + +=item * + +Fix a memory leak in RegEx +[L<GH #18604|https://github.com/Perl/perl5/issues/18604>] + +=back + +=head1 Modules and Pragmata + +=head2 New Modules and Pragmata + +=over 4 + +=item * + +L<ExtUtils::PL2Bat> 0.004 has been added to the Perl core. + +This module is a generalization of the C<pl2bat> script. It being a script has +led to at least two forks of this code; this module will unify them under one +implementation with tests. + +=back + +=head2 Updated Modules and Pragmata + +=over 4 + +=item * + +L<Archive::Tar> has been upgraded from version 2.36 to 2.38. + +=item * + +L<autodie> has been upgraded from version 2.32 to 2.34. + +=item * + +L<B> has been upgraded from version 1.80 to 1.82. + +=item * + +L<B::Deparse> has been upgraded from version 1.54 to 1.56. + +=item * + +L<bytes> has been upgraded from version 1.07 to 1.08. + +=item * + +L<Carp> has been upgraded from version 1.50 to 1.52. + +=item * + +L<Compress::Raw::Bzip2> has been upgraded from version 2.093 to 2.101. + +=item * + +L<Compress::Raw::Zlib> has been upgraded from version 2.093 to 2.101. + +=item * + +L<Config::Perl::V> has been upgraded from version 0.32 to 0.33. + +=item * + +L<CPAN> has been upgraded from version 2.27 to 2.28. + +=item * + +L<Data::Dumper> has been upgraded from version 2.174 to 2.179. + +=item * + +L<DB> has been upgraded from version 1.58 to 1.59. + +=item * + +L<DB_File> has been upgraded from version 1.853 to 1.855. + +=item * + +L<Devel::Peek> has been upgraded from version 1.28 to 1.30. + +=item * + +L<Devel::PPPort> has been upgraded from version 3.57 to 3.62. + +New C<PERL_VERSION_*> comparison macros are now available. + +C<ppport.h --api-info> no longer includes non-API info unless that is the only +match + +=item * + +L<Digest> has been upgraded from version 1.17_01 to 1.19. + +=item * + +L<Digest::MD5> has been upgraded from version 2.55_01 to 2.58. + +=item * + +L<DynaLoader> has been upgraded from version 1.47 to 1.50. + +=item * + +L<Encode> has been upgraded from version 3.06 to 3.08. + +=item * + +L<Env> has been upgraded from version 1.04 to 1.05. + +=item * + +L<Errno> has been upgraded from version 1.30 to 1.33. + +=item * + +L<experimental> has been upgraded from version 0.020 to 0.024. + +=item * + +L<Exporter> has been upgraded from version 5.74 to 5.76. + +=item * + +L<ExtUtils::CBuilder> has been upgraded from version 0.280234 to 0.280236. + +=item * + +L<ExtUtils::Install> has been upgraded from version 2.14 to 2.20. + +=item * + +L<ExtUtils::MakeMaker> has been upgraded from version 7.44 to 7.62. + +=item * + +L<ExtUtils::Manifest> has been upgraded from version 1.72 to 1.73. + +=item * + +L<ExtUtils::Miniperl> has been upgraded from version 1.09 to 1.10. + +=item * + +L<ExtUtils::ParseXS> has been upgraded from version 3.40 to 3.43. + +=item * + +L<ExtUtils::Typemaps> has been upgraded from version 3.38 to 3.43. + +=item * + +L<Fcntl> has been upgraded from version 1.13 to 1.14. + +=item * + +L<feature> has been upgraded from version 1.58 to 1.64. + +Added the default enabled C<bareword_filehandles> feature. + +A new L<multidimensional|feature/"The 'multidimensional' feature"> +feature has been added, which is enabled by +default but allows turning off L<multi-dimensional array +emulation|perldata/Multi-dimensional array emulation>. + +=item * + +L<File::Copy> has been upgraded from version 2.34 to 2.35. + +=item * + +L<File::Fetch> has been upgraded from version 0.56 to 1.00. + +=item * + +L<File::Find> has been upgraded from version 1.37 to 1.39. + +=item * + +L<File::Path> has been upgraded from version 2.16 to 2.18. + +=item * + +L<File::Spec> has been upgraded from version 3.78 to 3.80. + +=item * + +L<File::Temp> has been upgraded from version 0.2309 to 0.2311. + +=item * + +L<Filter::Util::Call> has been upgraded from version 1.59 to 1.60. + +=item * + +L<FindBin> has been upgraded from version 1.51 to 1.52. + +=item * + +L<GDBM_File> has been upgraded from version 1.18 to 1.19. + +New functions and compatibility for newer versions of GDBM. +[L<GH #18435|https://github.com/Perl/perl5/pull/18435>] + +=item * + +L<Getopt::Long> has been upgraded from version 2.51 to 2.52. + +=item * + +L<Getopt::Std> has been upgraded from version 1.12 to 1.13. + +=item * + +L<Hash::Util> has been upgraded from version 0.23 to 0.25. + +=item * + +L<Hash::Util::FieldHash> has been upgraded from version 1.20 to 1.21. + +=item * + +L<I18N::LangTags> has been upgraded from version 0.44 to 0.45. + +=item * + +L<if> has been upgraded from version 0.0608 to 0.0609. + +=item * + +L<IO> has been upgraded from version 1.43 to 1.46. + +IO::Socket now stores error messages in C<$IO::Socket::errstr>, in +addition to in C<$@>. + +The C<error> method now reports the error state for both the input and +output streams for sockets and character devices. Similarly +C<clearerr> now clears the error state for both streams. + +A spurious error reported for regular file handles has been +fixed in L<IO::Handle>. +[L<GH #18019|https://github.com/Perl/perl5/issues/18019>] + +=item * + +IO-Compress has been upgraded from version 2.093 to 2.102. + +bin/zipdetails version 2.02 + +=item * + +L<IO::Socket::IP> has been upgraded from version 0.39 to 0.41. + +=item * + +L<IO::Zlib> has been upgraded from version 1.10 to 1.11. + +=item * + +L<IPC::SysV> has been upgraded from version 2.07 to 2.09. + +=item * + +L<JSON::PP> has been upgraded from version 4.04 to 4.06. + +=item * + +The libnet distribution has been upgraded from version 3.11 to 3.13. + +=item * + +L<locale> has been upgraded from version 1.09 to 1.10. + +=item * + +L<Math::Complex> has been upgraded from version 1.5901 to 1.5902. + +=item * + +L<MIME::Base64> has been upgraded from version 3.15 to 3.16. + +=item * + +L<Module::CoreList> has been upgraded from version 5.20200620 to 5.20210520. + +=item * + +L<Module::Load> has been upgraded from version 0.34 to 0.36. + +=item * + +L<Module::Load::Conditional> has been upgraded from version 0.70 to 0.74. + +=item * + +L<mro> has been upgraded from version 1.23 to 1.25_001. + +=item * + +L<Net::Ping> has been upgraded from version 2.72 to 2.74. + +=item * + +L<NEXT> has been upgraded from version 0.67_01 to 0.68. + +=item * + +L<ODBM_File> has been upgraded from version 1.16 to 1.17. + +=item * + +L<Opcode> has been upgraded from version 1.47 to 1.50. + +=item * + +L<overload> has been upgraded from version 1.31 to 1.33. + +=item * + +L<perlfaq> has been upgraded from version 5.20200523 to 5.20210411. + +=item * + +L<PerlIO::encoding> has been upgraded from version 0.28 to 0.30. + +=item * + +L<PerlIO::mmap> has been upgraded from version 0.016 to 0.017. + +=item * + +L<PerlIO::scalar> has been upgraded from version 0.30 to 0.31. + +=item * + +L<PerlIO::via::QuotedPrint> has been upgraded from version 0.08 to 0.09. + +=item * + +L<Pod::Checker> has been upgraded from version 1.73 to 1.74. + +=item * + +L<Pod::Html> has been upgraded from version 1.25 to 1.27. + +=item * + +L<Pod::Simple> has been upgraded from version 3.40 to 3.42. + +=item * + +L<Pod::Usage> has been upgraded from version 1.69 to 2.01. + +=item * + +L<POSIX> has been upgraded from version 1.94 to 1.97. + +POSIX::signbit() behaviour has been improved. +[L<GH #18441|https://github.com/Perl/perl5/pull/18441>] + +Documentation for C<asctime> clarifies that the result is always in English. +(Use C<strftime> for a localized result.) + +=item * + +L<re> has been upgraded from version 0.40 to 0.41. + +(See under L</Internal Changes> for more information.) + +=item * + +L<Safe> has been upgraded from version 2.41 to 2.43. + +=item * + +L<Socket> has been upgraded from version 2.029 to 2.031. + +=item * + +L<Storable> has been upgraded from version 3.21 to 3.23. + +=item * + +L<strict> has been upgraded from version 1.11 to 1.12. + +=item * + +L<subs> has been upgraded from version 1.03 to 1.04. + +=item * + +L<Symbol> has been upgraded from version 1.08 to 1.09. + +=item * + +L<Test::Harness> has been upgraded from version 3.42 to 3.43. + +=item * + +L<Test::Simple> has been upgraded from version 1.302175 to 1.302183. + +=item * + +L<Text::Balanced> has been upgraded from version 2.03 to 2.04. + +=item * + +L<threads> has been upgraded from version 2.25 to 2.26. + +=item * + +L<threads::shared> has been upgraded from version 1.61 to 1.62. + +=item * + +L<Tie::RefHash> has been upgraded from version 1.39 to 1.40. + +=item * + +L<Time::HiRes> has been upgraded from version 1.9764 to 1.9767. + +=item * + +L<Time::Local> has been upgraded from version 1.28 to 1.30. + +=item * + +L<Unicode::Collate> has been upgraded from version 1.27 to 1.29. + +=item * + +L<Unicode::Normalize> has been upgraded from version 1.27 to 1.28. + +=item * + +L<utf8> has been upgraded from version 1.22 to 1.24. + +=item * + +L<version> has been upgraded from version 0.9924 to 0.9928. + +=item * + +L<warnings> has been upgraded from version 1.47 to 1.51. + +=item * + +L<Win32> has been upgraded from version 0.53 to 0.57. + +Fix calling convention for C<PFNRegGetValueA>. + +Added C<Win32::IsSymlinkCreationAllowed()>, +C<Win32::IsDeveloperModeEnabled()>, and C<Win32::GetProcessPrivileges()>. + +Removed old code for versions before Windows 2000. + +=item * + +L<XS::APItest> has been upgraded from version 1.09 to 1.16. + +=item * + +L<XS::Typemap> has been upgraded from version 0.17 to 0.18. + +=back + +=head1 Documentation + +=head2 New Documentation + +=head3 L<perldocstyle> + +This document is a guide for the authorship and maintenance of the +documentation that ships with Perl. + +=head3 L<perlgov> + +This document describes the goals, scope, system, and rules for Perl's new +governance model. + +Other pod files, most notably L<perlpolicy>, were amended to reflect +its adoption. + +=head2 Changes to Existing Documentation + +We have attempted to update the documentation to reflect the changes +listed in this document. If you find any we have missed, open an issue +at L<https://github.com/Perl/perl5/issues>. + +Additionally, the following selected changes have been made: + +=over 4 + +=item * + +L<perlapi>, L<perlguts>, L<perlxs>, and L<perlxstut> now prefer C<SvPVbyte> +over C<SvPV>. + +=item * + +References to B<Pumpking> have been replaced with a more accurate term or +B<Steering Council> where appropriate. + +=item * + +B<The Perl Steering Council> is now the fallback contact for security issues. + +=back + +=head3 L<perlapi> + +=over 4 + +=item * + +Efforts continue in improving the presentation of this document, and to +document more API elements. + +=back + +=head3 L<perlcommunity> + +=over 4 + +=item * + +The freenode IRC URL has been updated. + +=back + +=head3 L<perldebguts> + +=over 4 + +=item * + +Corrected the description of the scalar C<< ${"_<$filename"} >> +variables. + +=back + +=head3 L<perldiag> + +=over 4 + +=item * + +Now documents additional examples of "not imported" warnings. + +=back + +=head3 L<perlfaq> + +=over 4 + +=item * + +The Perl FAQ was updated to CPAN version 5.20201107 with minor +improvements. + +=back + +=head3 L<perlfunc> + +=over 4 + +=item * + +L<my()|perlfunc/my> and L<state()|perlfunc/state> now explicitly warn +the reader that lexical variables should typically not be redeclared +within the same scope or statement. +[L<GH #18389|https://github.com/Perl/perl5/issues/18389>] + +=item * + +The L<localtime|perlfunc/localtime> entry has been improved and now +also states that the result of the function is always in English. + +=item * + +L<msgsnd()|perlfunc/msgsnd> documented a length field included in the +packed C<MSG> parameter to C<msgsnd()>, but there was no such field. +C<MSG> contains only the type and the message content. + +=item * + +Better explanation of what happens when C<sleep> is called with a zero or +negative value. + +=item * + +Simplify the C<split()> documentation by removing the C<join()>s from the +examples +[L<GH #18676|https://github.com/Perl/perl5/issues/18676>] + +=back + +=head3 L<perlgit> + +=over 4 + +=item * + +document how to create a remote-tracking branch for every PR + +=item * + +document how to get a PR as a local branch + +=back + +=head3 L<perlguts> + +=over 4 + +=item * + +L<perlguts> now explains in greater detail the need to consult C<SvUTF8> +when calling C<SvPV> (or variants). A new "How do I pass a Perl string to a C +library?" section in the same document discusses when to use which style of +macro to read an SV's string value. + +=item * + +Corrected C<my_rpeep> example in perlguts. + +=item * + +A section has been added on the formatted printing of special sizes. + +=back + +=head3 L<perlop> + +=over 4 + +=item * + +The C<< <> >> and C<<< <<>> >>> operators are commonly referred to as +the diamond and double diamond operators respectively, but that wasn't +mentioned previously in their documentation. + +=item * + +Document range op behavior change. + +=back + +=head3 L<perlpacktut> + +=over 4 + +=item * + +Incorrect variables used in an example have been fixed. + +=back + +=head3 L<perlsyn> + +=over 4 + +=item * + +Document that caller() does not see try{} blocks + +=item * + +A new example shows how a lexical C<my> variable can be declared +during the initialization of a C<for> loop. + +=back + +=head3 L<perlunifaq> + +=over 4 + +=item * + +Fix description of what Perl does with unencoded strings + +=back + +=head1 Diagnostics + +The following additions or changes have been made to diagnostic output, +including warnings and fatal error messages. For the complete list of +diagnostic messages, see L<perldiag>. + +=head2 New Diagnostics + +=head3 New Errors + +=over 4 + +=item * + +L<Bareword filehandle "%s" not allowed under 'no feature "bareword_filehandles"'|perldiag/"Bareword filehandle "%s" not allowed under 'no feature "bareword_filehandles"'"> + +This accompanies the new +L<bareword_filehandles|feature/"The 'bareword_filehandles' feature."> feature. + +=item * + +L<Multidimensional hash lookup is disabled|perldiag/"Multidimensional hash lookup is disabled"> + +This accompanies the new +L<multidimensional|feature/"The 'multidimensional' feature"> feature. + +=back + +=head3 New Warnings + +=over 4 + +=item * + +L<Wide character in setenv key (encoding to utf8)|perldiag/"Wide character in %s"> + +Attempts to put wide characters into environment variable keys via C<%ENV> now +provoke this warning. + +=back + +=head2 Changes to Existing Diagnostics + +=over 4 + +=item * + +L<Error %s in expansion of %s|perldiag/"Error %s in expansion of %s"> + +An error was encountered in handling a user-defined property +(L<perlunicode/User-Defined Character Properties>). These are +programmer written subroutines, hence subject to errors that may +prevent them from compiling or running. + +=item * + +L<Infinite recursion in user-defined property|perldiag/"Infinite recursion in user-defined property"> + +A user-defined property (L<perlunicode/User-Defined Character Properties>) +can depend on the definitions of other user-defined +properties. If the chain of dependencies leads back to this property, +infinite recursion would occur, were it not for the check that raised +this error. + +=item * + +L<Timeout waiting for another thread to define \p{%s}|perldiag/"Timeout waiting for another thread to define \p{%s}"> + +The first time a user-defined property +(L<perlunicode/User-Defined Character Properties>) is used, its +definition is looked up and converted into an internal form for more +efficient handling in subsequent uses. There could be a race if two or +more threads tried to do this processing nearly simultaneously. + +=item * + +L<Unknown user-defined property name \p{%s}|perldiag/"Unknown user-defined property name \p{%s}"> + +You specified to use a property within the C<\p{...}> which was a +syntactically valid user-defined property, but no definition was found +for it + +=item * + +L<Too few arguments for subroutine '%s' (got %d; expected %d)|perldiag/"Too few arguments for subroutine '%s' (got %d; expected %d)"> + +Subroutine argument-count mismatch errors now include the number of +given and expected arguments. + +=item * + +L<Too many arguments for subroutine '%s' (got %d; expected %d)|perldiag/"Too many arguments for subroutine '%s' (got %d; expected %d)"> + +Subroutine argument-count mismatch errors now include the number of +given and expected arguments. + +=item * + +L<Lost precision when %s %f by 1|perldiag/"Lost precision when %s %f by 1"> + +This warning was only issued for positive too-large values when +incrementing, and only for negative ones when decrementing. +It is now issued for both positive or negative too-large values. +[L<GH #18333|https://github.com/Perl/perl5/issues/18333>] + +=item * + +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/"> + +This error was incorrectly produced in some cases involving nested +lookarounds. This has been fixed. +[L<GH #18123|https://github.com/Perl/perl5/issues/18123>] + +=item * + +L<Use of uninitialized value%s|perldiag/"Use of uninitialized value%s"> + +This warning may now include the array or hash index when the +uninitialized value is the result of an element not found. This will +only happen if the index is a simple non-magical variable. + +=back + +=head1 Utility Changes + +=head2 L<perl5db.pl> (the debugger) + +=over 4 + +=item * New option: C<HistItemMinLength> + +This option controls the minimum length a command must be to get stored in +history. Traditionally, this has been fixed at 2. Changes to the debugger +are often perilous, and new bugs should be reported so the debugger can be +debugged. + +=item * Fix to C<i> and C<l> commands + +The C<i $var> and C<l $var> commands work again with lexical variables. + +=back + +=head1 Configuration and Compilation + +=over 4 + +=item * + +Prevented incpath to spill into libpth + +=item * + +Use realpath if available. (This might catch more duplicate paths.) + +=item * + +Only include real existing paths. + +=item * + +Filter inc paths out of libpth. + +=item * stadtx hash support has been removed + +stadtx support has been entirely removed. Previously, it could be requested +with C<PERL_HASH_FUNC_STADTX>, and was default in 64-bit builds. It has been +replaced with SipHash. SipHash has been more rigorously reviewed than stadtx. + +=item * Configure + +A new probe checks for buggy libc implementations of the C<gcvt>/C<qgcvt> +functions. +[L<GH #18170|https://github.com/Perl/perl5/issues/18170>] + +=item * C<-Dusedefaultstrict> + +Perl can now be built with L<strict> on by default (using the configuration +option C<-Dusedefaultstrict>. + +These strict defaults do not apply when C<perl> is run via C<-e> or C<-E>. + +This setting provides a diagnostic mechanism intended for development +purposes only and is thus undefined by default. + +=item * + +The minimum supported Bison version is now 2.4, and the maximum is 3.7. + +=item * + +Newer 64-bit versions of the Intel C/C++ compiler are now recognised +and have the correct flags set. + +=item * + +We now trap SIGBUS when F<Configure> checks for C<va_copy>. + +On several systems the attempt to determine if we need C<va_copy> or similar +results in a SIGBUS instead of the expected SIGSEGV, which previously caused a +core dump. + +[L<GH #18148|https://github.com/Perl/perl5/issues/18148>] + +=back + +=head1 Testing + +Tests were added and changed to reflect the other additions and +changes in this release. Furthermore, these significant changes were +made: + +=over 4 + +=item * + +Split Config-dependent tests in F<t/opbasic/arith.t> to F<t/op/arith2.t> + +=item * + +F<t/re/opt.t> was added, providing a test harness for regexp optimization. +[L<GH #18213|https://github.com/Perl/perl5/pull/18213>] + +=item * + +A workaround for CPAN distributions needing dot in C<@INC> has been removed +[L<GH #18394|https://github.com/Perl/perl5/pull/18394>]. +All distributions that previously required the workaround have now been +adapted. + +=item * + +When testing in parallel on many-core platforms, you can now cause the +test suite to finish somewhat earlier, but with less logical ordering of +the tests, by setting + + PERL_TEST_HARNESS_ASAP=1 + +while running the test suite. + +=back + +=head1 Platform Support + +=head2 New Platforms + +=over 4 + +=item 9front + +Allow building Perl on i386 9front systems (a fork of plan9). + +=back + +=head2 Updated Platforms + +=over 4 + +=item Plan9 + +Improve support for Plan9 on i386 platforms. + +=item MacOS (Darwin) + +The hints file for darwin has been updated to handle future MacOS versions +beyond 10. [L<GH #17946|https://github.com/Perl/perl5/issues/17946>] + +=back + +=head2 Discontinued Platforms + +=over 4 + +=item Symbian + +Support code relating to Symbian has been removed. Symbian was an +operating system for mobile devices. The port was last updated in July +2009, and the platform itself in October 2012. + +=back + +=head2 Platform-Specific Notes + +=over 4 + +=item DragonFlyBSD + +Tests were updated to workaround DragonFlyBSD bugs in L<tc*() +functions|https://bugs.dragonflybsd.org/issues/3252> and L<ctime +updates|https://bugs.dragonflybsd.org/issues/3251>. + +=item Mac OS X + +A number of system libraries no longer exist as actual files on Big Sur, +even though C<dlopen> will pretend they do, so now we fall back to C<dlopen> +if a library file can not be found. +[L<GH #18407|https://github.com/Perl/perl5/issues/18407>] + +=item Windows + +Reading non-ASCII characters from the console when its codepage was set to +65001 (UTF-8) was broken due to a bug in Windows. A workaround for this +problem has been implemented. +[L<GH #18701|https://github.com/Perl/perl5/issues/18701>] + +Building with mingw.org compilers (version 3.4.5 or later) using mingw runtime +versions < 3.22 now works again. This was broken in Perl 5.31.4. + +Building with mingw.org compilers (version 3.4.5 or later) using mingw runtime +versions >= 3.21 now works (for compilers up to version 5.3.0). + +F<Makefile.mk>, and thus support for dmake, has been removed. It is still +possible to build Perl on Windows using nmake (Makefile) and GNU make +(GNUmakefile). +[L<GH #18511|https://github.com/Perl/perl5/pull/18511>] + +perl can now be built with C<USE_QUADMATH> on MS Windows using +(32-bit and 64-bit) mingw-w64 ports of gcc. +[L<GH #18465|https://github.com/Perl/perl5/pull/18465>] + +The F<pl2bat.pl> utility now needs to C<use ExtUtils::PL2Bat>. This could +cause failures in parallel builds. + +Windows now supports L<symlink()|perlfunc/symlink> and +L<readlink()|perlfunc/readlink>, and L<lstat()|perlfunc/lstat> is no +longer an alias for L<stat()|perlfunc/stat>. +[L<GH #18005|https://github.com/Perl/perl5/issues/18005>]. + +Unlike POSIX systems, creating a symbolic link on Windows requires +either elevated privileges or Windows 10 1703 or later with Developer +Mode enabled. + +stat(), including C<stat FILEHANDLE>, and lstat() now uses our own +implementation that populates the device C<dev> and inode numbers +C<ino> returned rather than always returning zero. The number of +links C<nlink> field is now always populated. + +L<< C<${^WIN32_SLOPPY_STAT}> |perlvar/${^WIN32_SLOPPY_STAT} >> previously +controlled whether the C<nlink> field was populated requiring a +separate Windows API call to fetch, since C<nlink> and the other +information required for C<stat()> is now retrieved in a single API call. + +The C<-r> and C<-w> operators now return true for the C<STDIN>, +C<STDOUT> and C<STDERR> handles. Unfortunately it still won't return +true for duplicates of those handles. +[L<GH #8502|https://github.com/Perl/perl5/issues/8502>]. + +The times returned by stat() and lstat() are no longer incorrect +across Daylight Savings Time adjustments. +[L<GH #6080|https://github.com/Perl/perl5/issues/6080>]. + +C<-x> on a filehandle should now match C<-x> on the corresponding +filename on Vista or later. +[L<GH #4145|https://github.com/Perl/perl5/issues/4145>]. + +C<-e '"'> no longer incorrectly returns true. +[L<GH #12431|https://github.com/Perl/perl5/issues/12431>]. + +The same manifest is now used for Visual C++ and gcc builds. + +Previously, MSVC builds were using the B</manifestdependency> flag instead of +embedding F<perlexe.manifest>, which caused issues such as C<GetVersionEx()> +returning the wrong version number on Windows 10. + +=item z/OS + +The locale categories C<LC_SYNTAX> and C<LC_TOD> are now recognized. +Perl doesn't do anything with these, except it now allows you to specify +them. They are included in C<LC_ALL>. + +=back + +=head1 Internal Changes + +=over 4 + +=item * + +Corrected handling of double and long double parameters for perl's +implementation of formatted output for C<-Dusequadmath> builds. + +This applies to C<PerlIO_printf()>, C<croak()>, C<warn()>, C<sv_catpvf()> and +their variants. + +Previously in C<quadmath> builds, code like: + + PerlIO_printf(PerlIO_stderr(), "%g", somedouble); + +or + + PerlIO_printf(PerlIO_stderr(), "%Lg", somelongdouble); + +would erroneously throw an exception "panic: quadmath invalid format +...", since the code added for quadmath builds assumed C<NV>s were the +only floating point format passed into these functions. + +This code would also process the standard C long double specifier C<L> +as if it expected an C<NV> (C<__float128> for quadmath builds), +resulting in undefined behaviour. + +These functions now correctly accept doubles, long doubles and NVs. + +=item * + +Previously the right operand of bitwise shift operators (shift amount) +was implicitly cast from IV to int, but it might lead wrong results +if IV does not fit in int. + +And also, shifting INT_MIN bits used to yield the shiftee unchanged +(treated as 0-bit shift instead of negative shift). + +=item * + +A set of C<cop_hints_exists_{pv,pvn,pvs,sv}> functions was added, +to support checking for the existence of keys in the hints hash of a +specific cop without needing to create a mortal copy of said value. + +=item * + +An aid has been added for using the C<DEBUG> macros when debugging XS or +C code. The comments in F<perl.h> describe C<DEBUG_PRE_STMTS> and +C<DEBUG_POST_STMTS>. which you can C<#define> to do things like save and +restore C<errno>, in case the C<DEBUG> calls are interfering with that, +or to display timestamps, or which thread it's coming from, or the +location of the call, or whatever. You can make a quick hack to help +you track something down without having to edit individual C<DEBUG> +calls. + +=item * + +Make C<REFCOUNTED_HE_EXISTS> available outside of core + +=item * + +All C<SvTRUE>-ish functions now evaluate their arguments exactly once. +In 5.32, plain L<perlapi/C<SvTRUE>> was changed to do that; now the rest +do as well. + +=item * + +Unicode is now a first class citizen when considering the pattern /A*B/ where +A and B are arbitrary. The pattern matching code tries to make a tight loop +to match the span of A's. The logic of this was now really updated with +support for UTF-8. + +=item * + +The L<re> module has a new function C<optimization>, which can return a +hashref of optimization data discovered about a compiled regexp. + +=item * + +The C<PERL_GLOBAL_STRUCT> compilation option has been removed, and +with it the need or the C<dVAR> macro. C<dVAR> remains defined as a +no-op outside C<PERL_CORE> for backwards compatiblity with XS modules. + +=item * + +A new savestack type C<SAVEt_HINTS_HH> has been added, which neatens the +previous behaviour of C<SAVEt_HINTS>. On previous versions the types and +values pushed to the save stack would depend on whether the hints included the +C<HINT_LOCALIZE_HH> bit, which complicates external code that inspects the +save stack. The new version uses a different savestack type to indicate the +difference. + +=item * + +A new API function L<perlapi/av_count> has been added which gives a +clearly named way to find how many elements are in an array. + +=back + +=head1 Selected Bug Fixes + +=over 4 + +=item * + +Setting C<%ENV> now properly handles upgraded strings in the key. Previously +Perl sent the SV's internal PV directly to the OS; now it will handle keys +as it has handled values since 5.18: attempt to downgrade the string first; +if that fails then warn and use the utf8 form. + +=item * + +Fix a memory leak in regcomp.c +[L<GH #18604|https://github.com/Perl/perl5/issues/18604>] + +=item * pack/unpack format 'D' now works on all systems that could support it + +Previously if C<NV == long double>, now it is supported on all platforms that +have long doubles. In particular that means it is now also supported on +quadmath platforms. + +=item * + +Skip trying to constant fold an incomplete op tree +[L<GH #18380|https://github.com/Perl/perl5/issues/18380>] + +Constant folding of chained comparison op trees could fail under certain +conditions, causing perl to crash. As a quick fix, constant folding is +now skipped for such op trees. This also addresses +[L<GH #17917|https://github.com/Perl/perl5/issues/17917>]. + +=item * + +C<%g> formatting broken on Ubuntu-18.04, C<NVSIZE == 8> +[L<GH #18170|https://github.com/Perl/perl5/issues/18170>] + +Buggy libc implementations of the C<gcvt> and C<qgcvt> functions +caused C<(s)printf> to incorrectly truncate C<%g> formatted numbers. +A new Configure probe now checks for this, with the result that the libc +C<sprintf> will be used in place of C<gcvt> and C<qgcvt>. + +Tests added as part of this fix also revealed related problems in +some Windows builds. The makefiles for MINGW builds on Windows have +thus been adjusted to use C<USE_MINGW_ANSI_STDIO> by default, ensuring +that they also provide correct C<(s)printf> formatting of numbers. + +=item * + +F<op.c>: croak on C<my $_> when C<use utf8> is in effect +[L<GH #18449|https://github.com/Perl/perl5/issues/18449>] + +The lexical topic feature experiment was removed in Perl v5.24 and +declaring C<my $_> became a compile time error. However, it was previously +still possible to make this declaration if C<use utf8> was in effect. + +=item * + +F<regexec.c>: Fix assertion failure +[L<GH #18451|https://github.com/Perl/perl5/issues/18451>] + +Fuzzing triggered an assertion failure in the regexp engine when too many +characters were copied into a buffer. + +=item * + +L<semctl()|perlfunc/semctl>, L<msgctl()|perlfunc/msgctl>, and +L<shmctl()|perlfunc/shmctl> now properly reset the UTF-8 flag on the +C<ARG> parameter if it's modified for C<IPC_STAT> or C<GETALL> +operations. + +=item * + +C<semctl()>, C<msgctl()>, and C<shmctl()> now attempt to downgrade the C<ARG> +parameter if its value is being used as input to C<IPC_SET> or +C<SETALL> calls. A failed downgrade will thrown an exception. + +=item * + +In cases where C<semctl()>, C<msgctl()> or C<shmctl()> would treat the C<ARG> +parameter as a pointer, an undefined value no longer generates a +warning. In most such calls the pointer isn't used anyway and this +allows you to supply C<undef> for a value not used by the underlying +function. + +=item * + +L<semop()|perlfunc/semop> now downgrades the C<OPSTRING> parameter, +L<msgsnd()|perlfunc/msgsnd> now downgrades the C<MSG> parameter and +L<shmwrite|perlfunc/shmwrite> now downgrades the C<STRING> parameter +to treat them as bytes. Previously they would be left upgraded, +providing a corrupted structure to the underlying function call. + +=item * + +L<msgrcv()|perlfunc/msgrcv> now properly resets the UTF-8 flag the +C<VAR> parameter when it is modified. Previously the UTF-8 flag could +be left on, resulting in a possibly corrupt result in C<VAR>. + +=item * + +Magic is now called correctly for stacked file test operators. +[L<GH #18293|https://github.com/Perl/perl5/issues/18293>] + +=item * + +The C<@ary = split(...)> optimization no longer switches in the target +array as the value stack. +[L<GH #18232|https://github.com/Perl/perl5/issues/18232>] +Also see discussion at +L<https://github.com/Perl/perl5/pull/18014#issuecomment-671299506>. + +=item * + +Fixed a bug in which some regexps with recursive subpatterns matched +incorrectly. + +[L<GH #18096|https://github.com/Perl/perl5/issues/18096>] + +=item * + +On Win32, C<waitpid(-1, WNOHANG)> could sometimes have a very large +timeout. [L<GH #16529|https://github.com/Perl/perl5/issues/16529>] + +=item * + +C<MARK> and hence C<items> are now correctly initialized in C<BOOT> XSUBs. + +=item * + +Some list assignments involving C<undef> on the left-hand side were +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>] + +=back + +=head1 Known Problems + +None + +=head1 Errata From Previous Releases + +None + +=head1 Obituary + +Kent Fredric (KENTNL) passed away in February 2021. A native of New Zealand +and a self-described "huge geek," Kent was the author or maintainer of 178 +CPAN distributions, the Perl maintainer for the Gentoo Linux distribution and +a contributor to the Perl core distribution. He is mourned by his family, +friends and open source software communities worldwide. + +=head1 Acknowledgements + +Perl 5.34.0 represents approximately 11 months of development since Perl +5.32.0 and contains approximately 280,000 lines of changes across 2,100 +files from 78 authors. + +Excluding auto-generated files, documentation and release tools, there were +approximately 150,000 lines of changes to 1,300 .pm, .t, .c and .h files. + +Perl continues to flourish into its fourth decade thanks to a vibrant +community of users and developers. The following people are known to have +contributed the improvements that became Perl 5.34.0: + +Aaron Crane, Adam Hartley, Andy Dougherty, Ben Cornett, Branislav +Zahradník, brian d foy, Chris 'BinGOs' Williams, Christian Walde +(Mithaldu), Craig A. Berry, Dagfinn Ilmari Mannsåker, Dan Book, Daniel +Böhmer, Daniel Laügt, Dan Kogai, David Cantrell, David Mitchell, Dominic +Hamon, E. Choroba, Ed J, Eric Herman, Eric Lindblad, Eugene Alvin Villar, +Felipe Gasper, Giovanni Tataranni, Graham Knop, Graham Ollis, Hauke D, +H.Merijn Brand, Hugo van der Sanden, Ichinose Shogo, Ivan Baidakou, Jae +Bradley, James E Keenan, Jason McIntosh, jkahrman, John Karr, John Lightsey, +Kang-min Liu, Karen Etheridge, Karl Williamson, Keith Thompson, Leon +Timmermans, Marc Reisner, Marcus Holland-Moritz, Max Maischein, Michael G +Schwern, Nicholas Clark, Nicolas R., Paul Evans, Petr Písař, raiph, Renee +Baecker, Ricardo Signes, Richard Leach, Romano, Ryan Voots, Samanta Navarro, +Samuel Thibault, Sawyer X, Scott Baker, Sergey Poznyakoff, Sevan Janiyan, +Shirakata Kentaro, Shlomi Fish, Sisyphus, Sizhe Zhao, Steve Hay, TAKAI +Kousuke, Thibault Duponchelle, Todd Rinaldo, Tomasz Konojacki, Tom Hukins, +Tom Stellard, Tony Cook, vividsnow, Yves Orton, Zakariyya Mughal, +Михаил Козачков. + +The list above is almost certainly incomplete as it is automatically +generated from version control history. In particular, it does not include +the names of the (very much appreciated) contributors who reported issues to +the Perl bug tracker. + +Many of the changes included in this version originated in the CPAN modules +included in Perl's core. We're grateful to the entire CPAN community for +helping Perl to flourish. + +For a more complete list of all of Perl's historical contributors, please +see the F<AUTHORS> file in the Perl source distribution. + +=head1 Reporting Bugs + +If you find what you think is a bug, you might check the perl bug database +at L<https://github.com/Perl/perl5/issues>. There may also be information at +L<http://www.perl.org/>, the Perl Home Page. + +If you believe you have an unreported bug, please open an issue at +L<https://github.com/Perl/perl5/issues>. Be sure to trim your bug down to a +tiny but sufficient test case. + +If the bug you are reporting has security implications which make it +inappropriate to send to a public issue tracker, then see +L<perlsec/SECURITY VULNERABILITY CONTACT INFORMATION> +for details of how to report the issue. + +=head1 Give Thanks + +If you wish to thank the Perl 5 Porters for the work we had done in Perl 5, +you can do so by running the C<perlthanks> program: + + perlthanks + +This will send an email to the Perl 5 Porters list with your show of thanks. + +=head1 SEE ALSO + +The F<Changes> file for an explanation of how to view exhaustive details on +what changed. + +The F<INSTALL> file for how to build Perl. + +The F<README> file for general stuff. + +The F<Artistic> and F<Copying> files for copyright information. + +=cut |