{ "mode": "man", "parameter": "perl5340delta", "section": "1", "url": "https://www.chedong.com/phpMan.php/man/perl5340delta/1/json", "generated": "2026-06-03T00:32:23Z", "sections": { "NAME": { "content": "perldelta - what is new for perl v5.34.0\n", "subsections": [] }, "DESCRIPTION": { "content": "This document describes differences between the 5.32.0 release and the 5.34.0 release.\n\nIf you are upgrading from an earlier release such as 5.30.0, first read perl5320delta, which\ndescribes differences between 5.30.0 and 5.32.0.\n", "subsections": [ { "name": "Core Enhancements", "content": "" }, { "name": "Experimental Try/Catch Syntax", "content": "An initial experimental attempt at providing \"try\"/\"catch\" notation has been added.\n\nuse feature 'try';\n\ntry {\nafunction();\n}\ncatch ($e) {\nwarn \"An error occurred: $e\";\n}\n\nFor more information, see \"Try Catch Exception Handling\" in perlsyn.\n" }, { "name": "\"qr/{,n}/\" is now accepted", "content": "An empty lower bound is now accepted for regular expression quantifiers, like \"{,3}\".\n" }, { "name": "Blanks freely allowed within but adjacent to curly braces", "content": "(in double-quotish contexts and regular expression patterns)\n\nThis means you can write things like \"\\x{ FFFC }\" if you like. This applies to all such\nconstructs, namely \"\\b{}\", \"\\g{}\", \"\\k{}\", \"\\N{}\", \"\\o{}\", and \"\\x{}\"; as well as the regular\nexpression quantifier \"{m,n}\". \"\\p{}\" and \"\\P{}\" retain their already-existing, even looser,\nrules mandated by the Unicode standard (see \"Properties accessible through \\p{} and \\P{}\" in\nperluniprops).\n\nThis ability is in effect regardless of the presence of the \"/x\" regular expression pattern\nmodifier.\n\nAdditionally, the comma in a regular expression braced quantifier may have blanks (tabs or\nspaces) before and/or after the comma, like \"qr/a{ 5, 7 }/\".\n\nNew octal syntax \"0oddddd\"\nIt is now possible to specify octal literals with \"0o\" prefixes, as in \"0o123456\", parallel\nto the existing construct to specify hexadecimal literal \"0xddddd\" and binary literal\n\"0bddddd\". Also, the builtin \"oct()\" function now accepts this new syntax.\n\nSee \"Scalar value constructors\" in perldata and \"oct EXPR\" in perlfunc.\n" }, { "name": "Performance Enhancements", "content": "• Fix a memory leak in RegEx [GH #18604 ]\n" }, { "name": "Modules and Pragmata", "content": "" }, { "name": "New Modules and Pragmata", "content": "• ExtUtils::PL2Bat 0.004 has been added to the Perl core.\n\nThis module is a generalization of the \"pl2bat\" script. It being a script has led to at\nleast two forks of this code; this module will unify them under one implementation with\ntests.\n" }, { "name": "Updated Modules and Pragmata", "content": "• Archive::Tar has been upgraded from version 2.36 to 2.38.\n\n• autodie has been upgraded from version 2.32 to 2.34.\n\n• B has been upgraded from version 1.80 to 1.82.\n\n• B::Deparse has been upgraded from version 1.54 to 1.56.\n\n• bytes has been upgraded from version 1.07 to 1.08.\n\n• Carp has been upgraded from version 1.50 to 1.52.\n\n• Compress::Raw::Bzip2 has been upgraded from version 2.093 to 2.101.\n\n• Compress::Raw::Zlib has been upgraded from version 2.093 to 2.101.\n\n• Config::Perl::V has been upgraded from version 0.32 to 0.33.\n\n• CPAN has been upgraded from version 2.27 to 2.28.\n\n• Data::Dumper has been upgraded from version 2.174 to 2.179.\n\n• DB has been upgraded from version 1.58 to 1.59.\n\n• DBFile has been upgraded from version 1.853 to 1.855.\n\n• Devel::Peek has been upgraded from version 1.28 to 1.30.\n\n• Devel::PPPort has been upgraded from version 3.57 to 3.62.\n\nNew \"PERLVERSION*\" comparison macros are now available.\n\n\"ppport.h --api-info\" no longer includes non-API info unless that is the only match\n\n• Digest has been upgraded from version 1.1701 to 1.19.\n\n• Digest::MD5 has been upgraded from version 2.5501 to 2.58.\n\n• DynaLoader has been upgraded from version 1.47 to 1.50.\n\n• Encode has been upgraded from version 3.06 to 3.08.\n\n• Env has been upgraded from version 1.04 to 1.05.\n\n• Errno has been upgraded from version 1.30 to 1.33.\n\n• experimental has been upgraded from version 0.020 to 0.024.\n\n• Exporter has been upgraded from version 5.74 to 5.76.\n\n• ExtUtils::CBuilder has been upgraded from version 0.280234 to 0.280236.\n\n• ExtUtils::Install has been upgraded from version 2.14 to 2.20.\n\n• ExtUtils::MakeMaker has been upgraded from version 7.44 to 7.62.\n\n• ExtUtils::Manifest has been upgraded from version 1.72 to 1.73.\n\n• ExtUtils::Miniperl has been upgraded from version 1.09 to 1.10.\n\n• ExtUtils::ParseXS has been upgraded from version 3.40 to 3.43.\n\n• ExtUtils::Typemaps has been upgraded from version 3.38 to 3.43.\n\n• Fcntl has been upgraded from version 1.13 to 1.14.\n\n• feature has been upgraded from version 1.58 to 1.64.\n\nAdded the default enabled \"barewordfilehandles\" feature.\n\nA new multidimensional feature has been added, which is enabled by default but allows\nturning off multi-dimensional array emulation.\n\n• File::Copy has been upgraded from version 2.34 to 2.35.\n\n• File::Fetch has been upgraded from version 0.56 to 1.00.\n\n• File::Find has been upgraded from version 1.37 to 1.39.\n\n• File::Path has been upgraded from version 2.16 to 2.18.\n\n• File::Spec has been upgraded from version 3.78 to 3.80.\n\n• File::Temp has been upgraded from version 0.2309 to 0.2311.\n\n• Filter::Util::Call has been upgraded from version 1.59 to 1.60.\n\n• FindBin has been upgraded from version 1.51 to 1.52.\n\n• GDBMFile has been upgraded from version 1.18 to 1.19.\n\nNew functions and compatibility for newer versions of GDBM. [GH #18435\n]\n\n• Getopt::Long has been upgraded from version 2.51 to 2.52.\n\n• Getopt::Std has been upgraded from version 1.12 to 1.13.\n\n• Hash::Util has been upgraded from version 0.23 to 0.25.\n\n• Hash::Util::FieldHash has been upgraded from version 1.20 to 1.21.\n\n• I18N::LangTags has been upgraded from version 0.44 to 0.45.\n\n• if has been upgraded from version 0.0608 to 0.0609.\n\n• IO has been upgraded from version 1.43 to 1.46.\n\nIO::Socket now stores error messages in $IO::Socket::errstr, in addition to in $@.\n\nThe \"error\" method now reports the error state for both the input and output streams for\nsockets and character devices. Similarly \"clearerr\" now clears the error state for both\nstreams.\n\nA spurious error reported for regular file handles has been fixed in IO::Handle. [GH\n#18019 ]\n\n• IO-Compress has been upgraded from version 2.093 to 2.102.\n\nbin/zipdetails version 2.02\n\n• IO::Socket::IP has been upgraded from version 0.39 to 0.41.\n\n• IO::Zlib has been upgraded from version 1.10 to 1.11.\n\n• IPC::SysV has been upgraded from version 2.07 to 2.09.\n\n• JSON::PP has been upgraded from version 4.04 to 4.06.\n\n• The libnet distribution has been upgraded from version 3.11 to 3.13.\n\n• locale has been upgraded from version 1.09 to 1.10.\n\n• Math::Complex has been upgraded from version 1.5901 to 1.5902.\n\n• MIME::Base64 has been upgraded from version 3.15 to 3.16.\n\n• Module::CoreList has been upgraded from version 5.20200620 to 5.20210520.\n\n• Module::Load has been upgraded from version 0.34 to 0.36.\n\n• Module::Load::Conditional has been upgraded from version 0.70 to 0.74.\n\n• mro has been upgraded from version 1.23 to 1.25001.\n\n• Net::Ping has been upgraded from version 2.72 to 2.74.\n\n• NEXT has been upgraded from version 0.6701 to 0.68.\n\n• ODBMFile has been upgraded from version 1.16 to 1.17.\n\n• Opcode has been upgraded from version 1.47 to 1.50.\n\n• overload has been upgraded from version 1.31 to 1.33.\n\n• perlfaq has been upgraded from version 5.20200523 to 5.20210411.\n\n• PerlIO::encoding has been upgraded from version 0.28 to 0.30.\n\n• PerlIO::mmap has been upgraded from version 0.016 to 0.017.\n\n• PerlIO::scalar has been upgraded from version 0.30 to 0.31.\n\n• PerlIO::via::QuotedPrint has been upgraded from version 0.08 to 0.09.\n\n• Pod::Checker has been upgraded from version 1.73 to 1.74.\n\n• Pod::Html has been upgraded from version 1.25 to 1.27.\n\n• Pod::Simple has been upgraded from version 3.40 to 3.42.\n\n• Pod::Usage has been upgraded from version 1.69 to 2.01.\n\n• POSIX has been upgraded from version 1.94 to 1.97.\n\nPOSIX::signbit() behaviour has been improved. [GH #18441\n]\n\nDocumentation for \"asctime\" clarifies that the result is always in English. (Use\n\"strftime\" for a localized result.)\n\n• re has been upgraded from version 0.40 to 0.41.\n\n(See under \"Internal Changes\" for more information.)\n\n• Safe has been upgraded from version 2.41 to 2.43.\n\n• Socket has been upgraded from version 2.029 to 2.031.\n\n• Storable has been upgraded from version 3.21 to 3.23.\n\n• strict has been upgraded from version 1.11 to 1.12.\n\n• subs has been upgraded from version 1.03 to 1.04.\n\n• Symbol has been upgraded from version 1.08 to 1.09.\n\n• Test::Harness has been upgraded from version 3.42 to 3.43.\n\n• Test::Simple has been upgraded from version 1.302175 to 1.302183.\n\n• Text::Balanced has been upgraded from version 2.03 to 2.04.\n\n• threads has been upgraded from version 2.25 to 2.26.\n\n• threads::shared has been upgraded from version 1.61 to 1.62.\n\n• Tie::RefHash has been upgraded from version 1.39 to 1.40.\n\n• Time::HiRes has been upgraded from version 1.9764 to 1.9767.\n\n• Time::Local has been upgraded from version 1.28 to 1.30.\n\n• Unicode::Collate has been upgraded from version 1.27 to 1.29.\n\n• Unicode::Normalize has been upgraded from version 1.27 to 1.28.\n\n• utf8 has been upgraded from version 1.22 to 1.24.\n\n• version has been upgraded from version 0.9924 to 0.9928.\n\n• warnings has been upgraded from version 1.47 to 1.51.\n\n• Win32 has been upgraded from version 0.53 to 0.57.\n\nFix calling convention for \"PFNRegGetValueA\".\n\nAdded \"Win32::IsSymlinkCreationAllowed()\", \"Win32::IsDeveloperModeEnabled()\", and\n\"Win32::GetProcessPrivileges()\".\n\nRemoved old code for versions before Windows 2000.\n\n• XS::APItest has been upgraded from version 1.09 to 1.16.\n\n• XS::Typemap has been upgraded from version 0.17 to 0.18.\n" } ] }, "Documentation": { "content": "", "subsections": [ { "name": "New Documentation", "content": "perldocstyle\n\nThis document is a guide for the authorship and maintenance of the documentation that ships\nwith Perl.\n\nperlgov\n\nThis document describes the goals, scope, system, and rules for Perl's new governance model.\n\nOther pod files, most notably perlpolicy, were amended to reflect its adoption.\n" }, { "name": "Changes to Existing Documentation", "content": "We have attempted to update the documentation to reflect the changes listed in this document.\nIf you find any we have missed, open an issue at .\n\nAdditionally, the following selected changes have been made:\n\n• perlapi, perlguts, perlxs, and perlxstut now prefer \"SvPVbyte\" over \"SvPV\".\n\n• References to Pumpking have been replaced with a more accurate term or Steering Council\nwhere appropriate.\n\n• The Perl Steering Council is now the fallback contact for security issues.\n\nperlapi\n\n• Efforts continue in improving the presentation of this document, and to document more API\nelements.\n\nperlcommunity\n\n• The freenode IRC URL has been updated.\n\nperldebguts\n\n• Corrected the description of the scalar \"${\"<$filename\"}\" variables.\n\nperldiag\n\n• Now documents additional examples of \"not imported\" warnings.\n\nperlfaq\n\n• The Perl FAQ was updated to CPAN version 5.20201107 with minor improvements.\n\nperlfunc\n\n• my() and state() now explicitly warn the reader that lexical variables should typically\nnot be redeclared within the same scope or statement. [GH #18389\n]\n\n• The localtime entry has been improved and now also states that the result of the function\nis always in English.\n\n• msgsnd() documented a length field included in the packed \"MSG\" parameter to \"msgsnd()\",\nbut there was no such field. \"MSG\" contains only the type and the message content.\n\n• Better explanation of what happens when \"sleep\" is called with a zero or negative value.\n\n• Simplify the \"split()\" documentation by removing the \"join()\"s from the examples [GH\n#18676 ]\n\nperlgit\n\n• document how to create a remote-tracking branch for every PR\n\n• document how to get a PR as a local branch\n\nperlguts\n\n• perlguts now explains in greater detail the need to consult \"SvUTF8\" when calling \"SvPV\"\n(or variants). A new \"How do I pass a Perl string to a C library?\" section in the same\ndocument discusses when to use which style of macro to read an SV's string value.\n\n• Corrected \"myrpeep\" example in perlguts.\n\n• A section has been added on the formatted printing of special sizes.\n\nperlop\n\n• The \"<>\" and \"<<>>\" operators are commonly referred to as the diamond and double diamond\noperators respectively, but that wasn't mentioned previously in their documentation.\n\n• Document range op behavior change.\n\nperlpacktut\n\n• Incorrect variables used in an example have been fixed.\n\nperlsyn\n\n• Document that caller() does not see try{} blocks\n\n• A new example shows how a lexical \"my\" variable can be declared during the initialization\nof a \"for\" loop.\n\nperlunifaq\n\n• Fix description of what Perl does with unencoded strings\n" } ] }, "Diagnostics": { "content": "The following additions or changes have been made to diagnostic output, including warnings\nand fatal error messages. For the complete list of diagnostic messages, see perldiag.\n", "subsections": [ { "name": "New Diagnostics", "content": "New Errors\n\n• Bareword filehandle \"%s\" not allowed under 'no feature \"barewordfilehandles\"'\n\nThis accompanies the new barewordfilehandles feature.\n\n• Multidimensional hash lookup is disabled\n\nThis accompanies the new multidimensional feature.\n\nNew Warnings\n\n• Wide character in setenv key (encoding to utf8)\n\nAttempts to put wide characters into environment variable keys via %ENV now provoke this\nwarning.\n" }, { "name": "Changes to Existing Diagnostics", "content": "• Error %s in expansion of %s\n\nAn error was encountered in handling a user-defined property (\"User-Defined Character\nProperties\" in perlunicode). These are programmer written subroutines, hence subject to\nerrors that may prevent them from compiling or running.\n\n• Infinite recursion in user-defined property\n\nA user-defined property (\"User-Defined Character Properties\" in perlunicode) can depend\non the definitions of other user-defined properties. If the chain of dependencies leads\nback to this property, infinite recursion would occur, were it not for the check that\nraised this error.\n\n• Timeout waiting for another thread to define \\p{%s}\n\nThe first time a user-defined property (\"User-Defined Character Properties\" in\nperlunicode) is used, its definition is looked up and converted into an internal form for\nmore efficient handling in subsequent uses. There could be a race if two or more threads\ntried to do this processing nearly simultaneously.\n\n• Unknown user-defined property name \\p{%s}\n\nYou specified to use a property within the \"\\p{...}\" which was a syntactically valid\nuser-defined property, but no definition was found for it\n\n• Too few arguments for subroutine '%s' (got %d; expected %d)\n\nSubroutine argument-count mismatch errors now include the number of given and expected\narguments.\n\n• Too many arguments for subroutine '%s' (got %d; expected %d)\n\nSubroutine argument-count mismatch errors now include the number of given and expected\narguments.\n\n• Lost precision when %s %f by 1\n\nThis warning was only issued for positive too-large values when incrementing, and only\nfor negative ones when decrementing. It is now issued for both positive or negative too-\nlarge values. [GH #18333 ]\n\n• \\K not permitted in lookahead/lookbehind in regex; marked by <-- HERE in m/%s/\n\nThis error was incorrectly produced in some cases involving nested lookarounds. This has\nbeen fixed. [GH #18123 ]\n\n• Use of uninitialized value%s\n\nThis warning may now include the array or hash index when the uninitialized value is the\nresult of an element not found. This will only happen if the index is a simple non-\nmagical variable.\n" }, { "name": "Utility Changes", "content": "" }, { "name": "perl5db.pl (the debugger)", "content": "• New option: \"HistItemMinLength\"\n\nThis option controls the minimum length a command must be to get stored in history.\nTraditionally, this has been fixed at 2. Changes to the debugger are often perilous, and\nnew bugs should be reported so the debugger can be debugged.\n\n• Fix to \"i\" and \"l\" commands\n\nThe \"i $var\" and \"l $var\" commands work again with lexical variables.\n" }, { "name": "Configuration and Compilation", "content": "• Prevented incpath to spill into libpth\n\n• Use realpath if available. (This might catch more duplicate paths.)\n\n• Only include real existing paths.\n\n• Filter inc paths out of libpth.\n\n• stadtx hash support has been removed\n\nstadtx support has been entirely removed. Previously, it could be requested with\n\"PERLHASHFUNCSTADTX\", and was default in 64-bit builds. It has been replaced with\nSipHash. SipHash has been more rigorously reviewed than stadtx.\n\n• Configure\n\nA new probe checks for buggy libc implementations of the \"gcvt\"/\"qgcvt\" functions. [GH\n#18170 ]\n\n• \"-Dusedefaultstrict\"\n\nPerl can now be built with strict on by default (using the configuration option\n\"-Dusedefaultstrict\".\n\nThese strict defaults do not apply when \"perl\" is run via \"-e\" or \"-E\".\n\nThis setting provides a diagnostic mechanism intended for development purposes only and\nis thus undefined by default.\n\n• The minimum supported Bison version is now 2.4, and the maximum is 3.7.\n\n• Newer 64-bit versions of the Intel C/C++ compiler are now recognised and have the correct\nflags set.\n\n• We now trap SIGBUS when Configure checks for \"vacopy\".\n\nOn several systems the attempt to determine if we need \"vacopy\" or similar results in a\nSIGBUS instead of the expected SIGSEGV, which previously caused a core dump.\n\n[GH #18148 ]\n" } ] }, "Testing": { "content": "Tests were added and changed to reflect the other additions and changes in this release.\nFurthermore, these significant changes were made:\n\n• Split Config-dependent tests in t/opbasic/arith.t to t/op/arith2.t\n\n• t/re/opt.t was added, providing a test harness for regexp optimization. [GH #18213\n]\n\n• A workaround for CPAN distributions needing dot in @INC has been removed [GH #18394\n]. All distributions that previously required\nthe workaround have now been adapted.\n\n• When testing in parallel on many-core platforms, you can now cause the test suite to\nfinish somewhat earlier, but with less logical ordering of the tests, by setting\n\nPERLTESTHARNESSASAP=1\n\nwhile running the test suite.\n", "subsections": [ { "name": "Platform Support", "content": "" }, { "name": "New Platforms", "content": "9front\nAllow building Perl on i386 9front systems (a fork of plan9).\n" }, { "name": "Updated Platforms", "content": "Plan9\nImprove support for Plan9 on i386 platforms.\n\nMacOS (Darwin)\nThe hints file for darwin has been updated to handle future MacOS versions beyond 10. [GH\n#17946 ]\n" }, { "name": "Discontinued Platforms", "content": "Symbian\nSupport code relating to Symbian has been removed. Symbian was an operating system for\nmobile devices. The port was last updated in July 2009, and the platform itself in\nOctober 2012.\n" }, { "name": "Platform-Specific Notes", "content": "DragonFlyBSD\nTests were updated to workaround DragonFlyBSD bugs in tc*() functions\n and ctime updates\n.\n\nMac OS X\nA number of system libraries no longer exist as actual files on Big Sur, even though\n\"dlopen\" will pretend they do, so now we fall back to \"dlopen\" if a library file can not\nbe found. [GH #18407 ]\n\nWindows\nReading non-ASCII characters from the console when its codepage was set to 65001 (UTF-8)\nwas broken due to a bug in Windows. A workaround for this problem has been implemented.\n[GH #18701 ]\n\nBuilding with mingw.org compilers (version 3.4.5 or later) using mingw runtime versions <\n3.22 now works again. This was broken in Perl 5.31.4.\n\nBuilding with mingw.org compilers (version 3.4.5 or later) using mingw runtime versions\n>= 3.21 now works (for compilers up to version 5.3.0).\n\nMakefile.mk, and thus support for dmake, has been removed. It is still possible to build\nPerl on Windows using nmake (Makefile) and GNU make (GNUmakefile). [GH #18511\n]\n\nperl can now be built with \"USEQUADMATH\" on MS Windows using (32-bit and 64-bit)\nmingw-w64 ports of gcc. [GH #18465 ]\n\nThe pl2bat.pl utility now needs to \"use ExtUtils::PL2Bat\". This could cause failures in\nparallel builds.\n\nWindows now supports symlink() and readlink(), and lstat() is no longer an alias for\nstat(). [GH #18005 ].\n\nUnlike POSIX systems, creating a symbolic link on Windows requires either elevated\nprivileges or Windows 10 1703 or later with Developer Mode enabled.\n\nstat(), including \"stat FILEHANDLE\", and lstat() now uses our own implementation that\npopulates the device \"dev\" and inode numbers \"ino\" returned rather than always returning\nzero. The number of links \"nlink\" field is now always populated.\n\n\"${^WIN32SLOPPYSTAT}\" previously controlled whether the \"nlink\" field was populated\nrequiring a separate Windows API call to fetch, since \"nlink\" and the other information\nrequired for \"stat()\" is now retrieved in a single API call.\n\nThe \"-r\" and \"-w\" operators now return true for the \"STDIN\", \"STDOUT\" and \"STDERR\"\nhandles. Unfortunately it still won't return true for duplicates of those handles. [GH\n#8502 ].\n\nThe times returned by stat() and lstat() are no longer incorrect across Daylight Savings\nTime adjustments. [GH #6080 ].\n\n\"-x\" on a filehandle should now match \"-x\" on the corresponding filename on Vista or\nlater. [GH #4145 ].\n\n\"-e '\"'\" no longer incorrectly returns true. [GH #12431\n].\n\nThe same manifest is now used for Visual C++ and gcc builds.\n\nPreviously, MSVC builds were using the /manifestdependency flag instead of embedding\nperlexe.manifest, which caused issues such as \"GetVersionEx()\" returning the wrong\nversion number on Windows 10.\n\nz/OS\nThe locale categories \"LCSYNTAX\" and \"LCTOD\" are now recognized. Perl doesn't do\nanything with these, except it now allows you to specify them. They are included in\n\"LCALL\".\n" }, { "name": "Internal Changes", "content": "• Corrected handling of double and long double parameters for perl's implementation of\nformatted output for \"-Dusequadmath\" builds.\n\nThis applies to \"PerlIOprintf()\", \"croak()\", \"warn()\", \"svcatpvf()\" and their variants.\n\nPreviously in \"quadmath\" builds, code like:\n\nPerlIOprintf(PerlIOstderr(), \"%g\", somedouble);\n\nor\n\nPerlIOprintf(PerlIOstderr(), \"%Lg\", somelongdouble);\n\nwould erroneously throw an exception \"panic: quadmath invalid format ...\", since the code\nadded for quadmath builds assumed \"NV\"s were the only floating point format passed into\nthese functions.\n\nThis code would also process the standard C long double specifier \"L\" as if it expected\nan \"NV\" (\"float128\" for quadmath builds), resulting in undefined behaviour.\n\nThese functions now correctly accept doubles, long doubles and NVs.\n\n• Previously the right operand of bitwise shift operators (shift amount) was implicitly\ncast from IV to int, but it might lead wrong results if IV does not fit in int.\n\nAnd also, shifting INTMIN bits used to yield the shiftee unchanged (treated as 0-bit\nshift instead of negative shift).\n\n• A set of \"cophintsexists{pv,pvn,pvs,sv}\" functions was added, to support checking for\nthe existence of keys in the hints hash of a specific cop without needing to create a\nmortal copy of said value.\n\n• An aid has been added for using the \"DEBUG\" macros when debugging XS or C code. The\ncomments in perl.h describe \"DEBUGPRESTMTS\" and \"DEBUGPOSTSTMTS\". which you can\n\"#define\" to do things like save and restore \"errno\", in case the \"DEBUG\" calls are\ninterfering with that, or to display timestamps, or which thread it's coming from, or the\nlocation of the call, or whatever. You can make a quick hack to help you track something\ndown without having to edit individual \"DEBUG\" calls.\n\n• Make \"REFCOUNTEDHEEXISTS\" available outside of core\n\n• All \"SvTRUE\"-ish functions now evaluate their arguments exactly once. In 5.32, plain\n\"\"SvTRUE\"\" in perlapi was changed to do that; now the rest do as well.\n\n• Unicode is now a first class citizen when considering the pattern /A*B/ where A and B are\narbitrary. The pattern matching code tries to make a tight loop to match the span of\nA's. The logic of this was now really updated with support for UTF-8.\n\n• The re module has a new function \"optimization\", which can return a hashref of\noptimization data discovered about a compiled regexp.\n\n• The \"PERLGLOBALSTRUCT\" compilation option has been removed, and with it the need or the\n\"dVAR\" macro. \"dVAR\" remains defined as a no-op outside \"PERLCORE\" for backwards\ncompatiblity with XS modules.\n\n• A new savestack type \"SAVEtHINTSHH\" has been added, which neatens the previous\nbehaviour of \"SAVEtHINTS\". On previous versions the types and values pushed to the save\nstack would depend on whether the hints included the \"HINTLOCALIZEHH\" bit, which\ncomplicates external code that inspects the save stack. The new version uses a different\nsavestack type to indicate the difference.\n\n• A new API function \"avcount\" in perlapi has been added which gives a clearly named way\nto find how many elements are in an array.\n" }, { "name": "Selected Bug Fixes", "content": "• Setting %ENV now properly handles upgraded strings in the key. Previously Perl sent the\nSV's internal PV directly to the OS; now it will handle keys as it has handled values\nsince 5.18: attempt to downgrade the string first; if that fails then warn and use the\nutf8 form.\n\n• Fix a memory leak in regcomp.c [GH #18604 ]\n\n• pack/unpack format 'D' now works on all systems that could support it\n\nPreviously if \"NV == long double\", now it is supported on all platforms that have long\ndoubles. In particular that means it is now also supported on quadmath platforms.\n\n• Skip trying to constant fold an incomplete op tree [GH #18380\n]\n\nConstant folding of chained comparison op trees could fail under certain conditions,\ncausing perl to crash. As a quick fix, constant folding is now skipped for such op trees.\nThis also addresses [GH #17917 ].\n\n• %g formatting broken on Ubuntu-18.04, \"NVSIZE == 8\" [GH #18170\n]\n\nBuggy libc implementations of the \"gcvt\" and \"qgcvt\" functions caused \"(s)printf\" to\nincorrectly truncate %g formatted numbers. A new Configure probe now checks for this,\nwith the result that the libc \"sprintf\" will be used in place of \"gcvt\" and \"qgcvt\".\n\nTests added as part of this fix also revealed related problems in some Windows builds.\nThe makefiles for MINGW builds on Windows have thus been adjusted to use\n\"USEMINGWANSISTDIO\" by default, ensuring that they also provide correct \"(s)printf\"\nformatting of numbers.\n\n• op.c: croak on \"my $\" when \"use utf8\" is in effect [GH #18449\n]\n\nThe lexical topic feature experiment was removed in Perl v5.24 and declaring \"my $\"\nbecame a compile time error. However, it was previously still possible to make this\ndeclaration if \"use utf8\" was in effect.\n\n• regexec.c: Fix assertion failure [GH #18451 ]\n\nFuzzing triggered an assertion failure in the regexp engine when too many characters were\ncopied into a buffer.\n\n• semctl(), msgctl(), and shmctl() now properly reset the UTF-8 flag on the \"ARG\" parameter\nif it's modified for \"IPCSTAT\" or \"GETALL\" operations.\n\n• \"semctl()\", \"msgctl()\", and \"shmctl()\" now attempt to downgrade the \"ARG\" parameter if\nits value is being used as input to \"IPCSET\" or \"SETALL\" calls. A failed downgrade will\nthrown an exception.\n\n• In cases where \"semctl()\", \"msgctl()\" or \"shmctl()\" would treat the \"ARG\" parameter as a\npointer, an undefined value no longer generates a warning. In most such calls the\npointer isn't used anyway and this allows you to supply \"undef\" for a value not used by\nthe underlying function.\n\n• semop() now downgrades the \"OPSTRING\" parameter, msgsnd() now downgrades the \"MSG\"\nparameter and shmwrite now downgrades the \"STRING\" parameter to treat them as bytes.\nPreviously they would be left upgraded, providing a corrupted structure to the underlying\nfunction call.\n\n• msgrcv() now properly resets the UTF-8 flag the \"VAR\" parameter when it is modified.\nPreviously the UTF-8 flag could be left on, resulting in a possibly corrupt result in\n\"VAR\".\n\n• Magic is now called correctly for stacked file test operators. [GH #18293\n]\n\n• The \"@ary = split(...)\" optimization no longer switches in the target array as the value\nstack. [GH #18232 ] Also see discussion at\n.\n\n• Fixed a bug in which some regexps with recursive subpatterns matched incorrectly.\n\n[GH #18096 ]\n\n• On Win32, \"waitpid(-1, WNOHANG)\" could sometimes have a very large timeout. [GH #16529\n]\n\n• \"MARK\" and hence \"items\" are now correctly initialized in \"BOOT\" XSUBs.\n\n• Some list assignments involving \"undef\" on the left-hand side were over-optimized and\nproduced incorrect results. [GH #16685 ],\n[GH #17816 ]\n" }, { "name": "Known Problems", "content": "None\n" }, { "name": "Errata From Previous Releases", "content": "None\n" } ] }, "Obituary": { "content": "Kent Fredric (KENTNL) passed away in February 2021. A native of New Zealand and a self-\ndescribed \"huge geek,\" Kent was the author or maintainer of 178 CPAN distributions, the Perl\nmaintainer for the Gentoo Linux distribution and a contributor to the Perl core distribution.\nHe is mourned by his family, friends and open source software communities worldwide.\n", "subsections": [] }, "Acknowledgements": { "content": "Perl 5.34.0 represents approximately 11 months of development since Perl 5.32.0 and contains\napproximately 280,000 lines of changes across 2,100 files from 78 authors.\n\nExcluding auto-generated files, documentation and release tools, there were approximately\n150,000 lines of changes to 1,300 .pm, .t, .c and .h files.\n\nPerl continues to flourish into its fourth decade thanks to a vibrant community of users and\ndevelopers. The following people are known to have contributed the improvements that became\nPerl 5.34.0:\n\nAaron Crane, Adam Hartley, Andy Dougherty, Ben Cornett, Branislav Zahradník, brian d foy,\nChris 'BinGOs' Williams, Christian Walde (Mithaldu), Craig A. Berry, Dagfinn Ilmari\nMannsåker, Dan Book, Daniel Böhmer, Daniel Laügt, Dan Kogai, David Cantrell, David Mitchell,\nDominic Hamon, E. Choroba, Ed J, Eric Herman, Eric Lindblad, Eugene Alvin Villar, Felipe\nGasper, Giovanni Tataranni, Graham Knop, Graham Ollis, Hauke D, H.Merijn Brand, Hugo van der\nSanden, Ichinose Shogo, Ivan Baidakou, Jae Bradley, James E Keenan, Jason McIntosh, jkahrman,\nJohn Karr, John Lightsey, Kang-min Liu, Karen Etheridge, Karl Williamson, Keith Thompson,\nLeon Timmermans, Marc Reisner, Marcus Holland-Moritz, Max Maischein, Michael G Schwern,\nNicholas Clark, Nicolas R., Paul Evans, Petr Písař, raiph, Renee Baecker, Ricardo Signes,\nRichard Leach, Romano, Ryan Voots, Samanta Navarro, Samuel Thibault, Sawyer X, Scott Baker,\nSergey Poznyakoff, Sevan Janiyan, Shirakata Kentaro, Shlomi Fish, Sisyphus, Sizhe Zhao, Steve\nHay, TAKAI Kousuke, Thibault Duponchelle, Todd Rinaldo, Tomasz Konojacki, Tom Hukins, Tom\nStellard, Tony Cook, vividsnow, Yves Orton, Zakariyya Mughal, Михаил Козачков.\n\nThe list above is almost certainly incomplete as it is automatically generated from version\ncontrol history. In particular, it does not include the names of the (very much appreciated)\ncontributors who reported issues to the Perl bug tracker.\n\nMany of the changes included in this version originated in the CPAN modules included in\nPerl's core. We're grateful to the entire CPAN community for helping Perl to flourish.\n\nFor a more complete list of all of Perl's historical contributors, please see the AUTHORS\nfile in the Perl source distribution.\n", "subsections": [ { "name": "Reporting Bugs", "content": "If you find what you think is a bug, you might check the perl bug database at\n. There may also be information at\n, the Perl Home Page.\n\nIf you believe you have an unreported bug, please open an issue at\n. Be sure to trim your bug down to a tiny but\nsufficient test case.\n\nIf the bug you are reporting has security implications which make it inappropriate to send to\na public issue tracker, then see \"SECURITY VULNERABILITY CONTACT INFORMATION\" in perlsec for\ndetails of how to report the issue.\n" }, { "name": "Give Thanks", "content": "If you wish to thank the Perl 5 Porters for the work we had done in Perl 5, you can do so by\nrunning the \"perlthanks\" program:\n\nperlthanks\n\nThis will send an email to the Perl 5 Porters list with your show of thanks.\n" } ] }, "SEE ALSO": { "content": "The Changes file for an explanation of how to view exhaustive details on what changed.\n\nThe INSTALL file for how to build Perl.\n\nThe README file for general stuff.\n\nThe Artistic and Copying files for copyright information.\n\n\n\nperl v5.34.0 2025-07-25 PERL5340DELTA(1)", "subsections": [] } }, "summary": "perldelta - what is new for perl v5.34.0", "flags": [], "examples": [], "see_also": [] }