{ "content": [ { "type": "text", "text": "# perl5005delta (man)\n\n## NAME\n\nperl5005delta - what's new for perl5.005\n\n## DESCRIPTION\n\nThis document describes differences between the 5.004 release and this one.\n\n## Sections\n\n- **NAME**\n- **DESCRIPTION** (57 subsections)\n- **BUGS**\n- **SEE ALSO**\n- **HISTORY**\n\nUse structuredContent.sections for detailed options, examples, and full documentation.\n" } ], "structuredContent": { "command": "perl5005delta", "section": "", "mode": "man", "summary": "perl5005delta - what's new for perl5.005", "synopsis": null, "tldr_summary": null, "tldr_examples": [], "tldr_source": null, "flags": [], "examples": [], "see_also": [], "section_outline": [ { "name": "NAME", "lines": 2, "subsections": [] }, { "name": "DESCRIPTION", "lines": 2, "subsections": [ { "name": "About the new versioning system", "lines": 8 }, { "name": "Incompatible Changes", "lines": 1 }, { "name": "WARNING: This version is not binary compatible with Perl 5.004.", "lines": 5 }, { "name": "Default installation structure has changed", "lines": 4 }, { "name": "Perl Source Compatibility", "lines": 16 }, { "name": "C Source Compatibility", "lines": 37 }, { "name": "Binary Compatibility", "lines": 7 }, { "name": "Security fixes may affect compatibility", "lines": 7 }, { "name": "Relaxed new mandatory warnings introduced in 5.004", "lines": 4 }, { "name": "Licensing", "lines": 8 }, { "name": "Core Changes", "lines": 1 }, { "name": "Threads", "lines": 6 }, { "name": "Compiler", "lines": 31 }, { "name": "Regular Expressions", "lines": 70 }, { "name": "Improved malloc()", "lines": 2 }, { "name": "Quicksort is internally implemented", "lines": 8 }, { "name": "Reliable signals", "lines": 6 }, { "name": "Reliable stack pointers", "lines": 5 }, { "name": "More generous treatment of carriage returns", "lines": 14 }, { "name": "Memory leaks", "lines": 3 }, { "name": "Better support for multiple interpreters", "lines": 4 }, { "name": "Behavior of local() on array and hash elements is now well-defined", "lines": 2 }, { "name": "\"%!\" is transparently tied to the Errno module", "lines": 2 }, { "name": "Pseudo-hashes are supported", "lines": 2 }, { "name": "\"EXPR foreach EXPR\" is supported", "lines": 2 }, { "name": "Keywords can be globally overridden", "lines": 2 }, { "name": "$^E is meaningful on Win32", "lines": 2 }, { "name": "\"foreach (1..1000000)\" optimized", "lines": 3 }, { "name": "\"Foo::\" can be used as implicitly quoted package name", "lines": 6 }, { "name": "\"exists $Foo::{Bar::}\" tests existence of a package", "lines": 3 }, { "name": "Better locale support", "lines": 2 }, { "name": "Experimental support for 64-bit platforms", "lines": 8 }, { "name": "prototype() returns useful results on builtins", "lines": 2 }, { "name": "Extended support for exception handling", "lines": 4 }, { "name": "Re-blessing in DESTROY() supported for chaining DESTROY() methods", "lines": 2 }, { "name": "All \"printf\" format conversions are handled internally", "lines": 2 }, { "name": "New \"INIT\" keyword", "lines": 4 }, { "name": "New \"lock\" keyword", "lines": 6 }, { "name": "New \"qr//\" operator", "lines": 4 }, { "name": "\"our\" is now a reserved word", "lines": 3 }, { "name": "Tied arrays are now fully supported", "lines": 2 }, { "name": "Tied handles support is better", "lines": 3 }, { "name": "4th argument to substr", "lines": 3 }, { "name": "Negative LENGTH argument to splice", "lines": 3 }, { "name": "Magic lvalues are now more magical", "lines": 18 }, { "name": "<> now reads in records", "lines": 3 }, { "name": "Supported Platforms", "lines": 4 }, { "name": "New Platforms", "lines": 14 }, { "name": "Changes in existing support", "lines": 8 }, { "name": "Modules and Pragmata", "lines": 1 }, { "name": "New Modules", "lines": 46 }, { "name": "Changes in existing modules", "lines": 47 }, { "name": "Utility Changes", "lines": 11 }, { "name": "Documentation Changes", "lines": 16 }, { "name": "New Diagnostics", "lines": 160 }, { "name": "Obsolete Diagnostics", "lines": 24 }, { "name": "Configuration Changes", "lines": 4 } ] }, { "name": "BUGS", "lines": 9, "subsections": [] }, { "name": "SEE ALSO", "lines": 8, "subsections": [] }, { "name": "HISTORY", "lines": 8, "subsections": [] } ], "sections": { "NAME": { "content": "perl5005delta - what's new for perl5.005\n", "subsections": [] }, "DESCRIPTION": { "content": "This document describes differences between the 5.004 release and this one.\n", "subsections": [ { "name": "About the new versioning system", "content": "Perl is now developed on two tracks: a maintenance track that makes small, safe updates to\nreleased production versions with emphasis on compatibility; and a development track that\npursues more aggressive evolution. Maintenance releases (which should be considered\nproduction quality) have subversion numbers that run from 1 to 49, and development releases\n(which should be considered \"alpha\" quality) run from 50 to 99.\n\nPerl 5.005 is the combined product of the new dual-track development scheme.\n" }, { "name": "Incompatible Changes", "content": "" }, { "name": "WARNING: This version is not binary compatible with Perl 5.004.", "content": "Starting with Perl 5.00450 there were many deep and far-reaching changes to the language\ninternals. If you have dynamically loaded extensions that you built under perl 5.003 or\n5.004, you can continue to use them with 5.004, but you will need to rebuild and reinstall\nthose extensions to use them 5.005. See INSTALL for detailed instructions on how to upgrade.\n" }, { "name": "Default installation structure has changed", "content": "The new Configure defaults are designed to allow a smooth upgrade from 5.004 to 5.005, but\nyou should read INSTALL for a detailed discussion of the changes in order to adapt them to\nyour system.\n" }, { "name": "Perl Source Compatibility", "content": "When none of the experimental features are enabled, there should be very few user-visible\nPerl source compatibility issues.\n\nIf threads are enabled, then some caveats apply. @ and $ become lexical variables. The\neffect of this should be largely transparent to the user, but there are some boundary\nconditions under which user will need to be aware of the issues. For example, \"local(@)\"\nresults in a \"Can't localize lexical variable @ ...\" message. This may be enabled in a\nfuture version.\n\nSome new keywords have been introduced. These are generally expected to have very little\nimpact on compatibility. See \"New \"INIT\" keyword\", \"New \"lock\" keyword\", and \"New \"qr//\"\noperator\".\n\nCertain barewords are now reserved. Use of these will provoke a warning if you have asked\nfor them with the \"-w\" switch. See \"\"our\" is now a reserved word\".\n" }, { "name": "C Source Compatibility", "content": "There have been a large number of changes in the internals to support the new features in\nthis release.\n\n• Core sources now require ANSI C compiler\n\nAn ANSI C compiler is now required to build perl. See INSTALL.\n\n• All Perl global variables must now be referenced with an explicit prefix\n\nAll Perl global variables that are visible for use by extensions now have a \"PL\" prefix.\nNew extensions should \"not\" refer to perl globals by their unqualified names. To\npreserve sanity, we provide limited backward compatibility for globals that are being\nwidely used like \"svundef\" and \"na\" (which should now be written as \"PLsvundef\",\n\"PLna\" etc.)\n\nIf you find that your XS extension does not compile anymore because a perl global is not\nvisible, try adding a \"PL\" prefix to the global and rebuild.\n\nIt is strongly recommended that all functions in the Perl API that don't begin with\n\"perl\" be referenced with a \"Perl\" prefix. The bare function names without the \"Perl\"\nprefix are supported with macros, but this support may cease in a future release.\n\nSee perlapi.\n\n• Enabling threads has source compatibility issues\n\nPerl built with threading enabled requires extensions to use the new \"dTHR\" macro to\ninitialize the handle to access per-thread data. If you see a compiler error that talks\nabout the variable \"thr\" not being declared (when building a module that has XS code),\nyou need to add \"dTHR;\" at the beginning of the block that elicited the error.\n\nThe API function \"perlgetsv(\"@\",GVADD)\" should be used instead of directly accessing\nperl globals as \"GvSV(errgv)\". The API call is backward compatible with existing perls\nand provides source compatibility with threading is enabled.\n\nSee \"C Source Compatibility\" for more information.\n" }, { "name": "Binary Compatibility", "content": "This version is NOT binary compatible with older versions. All extensions will need to be\nrecompiled. Further binaries built with threads enabled are incompatible with binaries built\nwithout. This should largely be transparent to the user, as all binary incompatible\nconfigurations have their own unique architecture name, and extension binaries get installed\nat unique locations. This allows coexistence of several configurations in the same directory\nhierarchy. See INSTALL.\n" }, { "name": "Security fixes may affect compatibility", "content": "A few taint leaks and taint omissions have been corrected. This may lead to \"failure\" of\nscripts that used to work with older versions. Compiling with -DINCOMPLETETAINTS provides a\nperl with minimal amounts of changes to the tainting behavior. But note that the resulting\nperl will have known insecurities.\n\nOneliners with the \"-e\" switch do not create temporary files anymore.\n" }, { "name": "Relaxed new mandatory warnings introduced in 5.004", "content": "Many new warnings that were introduced in 5.004 have been made optional. Some of these\nwarnings are still present, but perl's new features make them less often a problem. See \"New\nDiagnostics\".\n" }, { "name": "Licensing", "content": "Perl has a new Social Contract for contributors. See Porting/Contract.\n\nThe license included in much of the Perl documentation has changed. Most of the Perl\ndocumentation was previously under the implicit GNU General Public License or the Artistic\nLicense (at the user's choice). Now much of the documentation unambiguously states the terms\nunder which it may be distributed. Those terms are in general much less restrictive than the\nGNU GPL. See perl and the individual perl manpages listed therein.\n" }, { "name": "Core Changes", "content": "" }, { "name": "Threads", "content": "WARNING: Threading is considered an experimental feature. Details of the implementation may\nchange without notice. There are known limitations and some bugs. These are expected to be\nfixed in future versions.\n\nSee README.threads.\n" }, { "name": "Compiler", "content": "WARNING: The Compiler and related tools are considered experimental. Features may change\nwithout notice, and there are known limitations and bugs. Since the compiler is fully\nexternal to perl, the default configuration will build and install it.\n\nThe Compiler produces three different types of transformations of a perl program. The C\nbackend generates C code that captures perl's state just before execution begins. It\neliminates the compile-time overheads of the regular perl interpreter, but the run-time\nperformance remains comparatively the same. The CC backend generates optimized C code\nequivalent to the code path at run-time. The CC backend has greater potential for big\noptimizations, but only a few optimizations are implemented currently. The Bytecode backend\ngenerates a platform independent bytecode representation of the interpreter's state just\nbefore execution. Thus, the Bytecode back end also eliminates much of the compilation\noverhead of the interpreter.\n\nThe compiler comes with several valuable utilities.\n\n\"B::Lint\" is an experimental module to detect and warn about suspicious code, especially the\ncases that the \"-w\" switch does not detect.\n\n\"B::Deparse\" can be used to demystify perl code, and understand how perl optimizes certain\nconstructs.\n\n\"B::Xref\" generates cross reference reports of all definition and use of variables,\nsubroutines and formats in a program.\n\n\"B::Showlex\" show the lexical variables used by a subroutine or file at a glance.\n\n\"perlcc\" is a simple frontend for compiling perl.\n\nSee \"ext/B/README\", B, and the respective compiler modules.\n" }, { "name": "Regular Expressions", "content": "Perl's regular expression engine has been seriously overhauled, and many new constructs are\nsupported. Several bugs have been fixed.\n\nHere is an itemized summary:\n\nMany new and improved optimizations\nChanges in the RE engine:\n\nUnneeded nodes removed;\nSubstrings merged together;\nNew types of nodes to process (SUBEXPR)* and similar expressions\nquickly, used if the SUBEXPR has no side effects and matches\nstrings of the same length;\nBetter optimizations by lookup for constant substrings;\nBetter search for constants substrings anchored by $ ;\n\nChanges in Perl code using RE engine:\n\nMore optimizations to s/longer/short/;\nstudy() was not working;\n/blah/ may be optimized to an analogue of index() if $& $` $' not seen;\nUnneeded copying of matched-against string removed;\nOnly matched part of the string is copying if $` $' were not seen;\n\nMany bug fixes\nNote that only the major bug fixes are listed here. See Changes for others.\n\nBacktracking might not restore start of $3.\nNo feedback if max count for * or + on \"complex\" subexpression\nwas reached, similarly (but at compile time) for {3,34567}\nPrimitive restrictions on max count introduced to decrease a\npossibility of a segfault;\n(ZERO-LENGTH)* could segfault;\n(ZERO-LENGTH)* was prohibited;\nLong REs were not allowed;\n/RE/g could skip matches at the same position after a\nzero-length match;\n\nNew regular expression constructs\nThe following new syntax elements are supported:\n\n(?<=RE)\n(?RE)\n\\z\n\nNew operator for precompiled regular expressions\nSee \"New \"qr//\" operator\".\n\nOther improvements\nBetter debugging output (possibly with colors),\neven from non-debugging Perl;\nRE engine code now looks like C, not like assembler;\nBehaviour of RE modifiable by `use re' directive;\nImproved documentation;\nTest suite significantly extended;\nSyntax [:^upper:] etc., reserved inside character classes;\n\nIncompatible changes\n(?i) localized inside enclosing group;\n$( is not interpolated into RE any more;\n/RE/g may match at the same position (with non-zero length)\nafter a zero-length match (bug fix).\n\nSee perlre and perlop.\n" }, { "name": "Improved malloc()", "content": "See banner at the beginning of \"malloc.c\" for details.\n" }, { "name": "Quicksort is internally implemented", "content": "Perl now contains its own highly optimized qsort() routine. The new qsort() is resistant to\ninconsistent comparison functions, so Perl's \"sort()\" will not provoke coredumps any more\nwhen given poorly written sort subroutines. (Some C library \"qsort()\"s that were being used\nbefore used to have this problem.) In our testing, the new \"qsort()\" required the minimal\nnumber of pair-wise compares on average, among all known \"qsort()\" implementations.\n\nSee \"perlfunc/sort\".\n" }, { "name": "Reliable signals", "content": "Perl's signal handling is susceptible to random crashes, because signals arrive\nasynchronously, and the Perl runtime is not reentrant at arbitrary times.\n\nHowever, one experimental implementation of reliable signals is available when threads are\nenabled. See \"Thread::Signal\". Also see INSTALL for how to build a Perl capable of threads.\n" }, { "name": "Reliable stack pointers", "content": "The internals now reallocate the perl stack only at predictable times. In particular, magic\ncalls never trigger reallocations of the stack, because all reentrancy of the runtime is\nhandled using a \"stack of stacks\". This should improve reliability of cached stack pointers\nin the internals and in XSUBs.\n" }, { "name": "More generous treatment of carriage returns", "content": "Perl used to complain if it encountered literal carriage returns in scripts. Now they are\nmostly treated like whitespace within program text. Inside string literals and here\ndocuments, literal carriage returns are ignored if they occur paired with linefeeds, or get\ninterpreted as whitespace if they stand alone. This behavior means that literal carriage\nreturns in files should be avoided. You can get the older, more compatible (but less\ngenerous) behavior by defining the preprocessor symbol \"PERLSTRICTCR\" when building perl.\nOf course, all this has nothing whatever to do with how escapes like \"\\r\" are handled within\nstrings.\n\nNote that this doesn't somehow magically allow you to keep all text files in DOS format. The\ngenerous treatment only applies to files that perl itself parses. If your C compiler doesn't\nallow carriage returns in files, you may still be unable to build modules that need a C\ncompiler.\n" }, { "name": "Memory leaks", "content": "\"substr\", \"pos\" and \"vec\" don't leak memory anymore when used in lvalue context. Many small\nleaks that impacted applications that embed multiple interpreters have been fixed.\n" }, { "name": "Better support for multiple interpreters", "content": "The build-time option \"-DMULTIPLICITY\" has had many of the details reworked. Some previously\nglobal variables that should have been per-interpreter now are. With care, this allows\ninterpreters to call each other. See the \"PerlInterp\" extension on CPAN.\n" }, { "name": "Behavior of local() on array and hash elements is now well-defined", "content": "See \"Temporary Values via local()\" in perlsub.\n" }, { "name": "\"%!\" is transparently tied to the Errno module", "content": "See perlvar, and Errno.\n" }, { "name": "Pseudo-hashes are supported", "content": "See perlref.\n" }, { "name": "\"EXPR foreach EXPR\" is supported", "content": "See perlsyn.\n" }, { "name": "Keywords can be globally overridden", "content": "See perlsub.\n" }, { "name": "$^E is meaningful on Win32", "content": "See perlvar.\n" }, { "name": "\"foreach (1..1000000)\" optimized", "content": "\"foreach (1..1000000)\" is now optimized into a counting loop. It does not try to allocate a\n1000000-size list anymore.\n" }, { "name": "\"Foo::\" can be used as implicitly quoted package name", "content": "Barewords caused unintuitive behavior when a subroutine with the same name as a package\nhappened to be defined. Thus, \"new Foo @args\", use the result of the call to \"Foo()\" instead\nof \"Foo\" being treated as a literal. The recommended way to write barewords in the indirect\nobject slot is \"new Foo:: @args\". Note that the method \"new()\" is called with a first\nargument of \"Foo\", not \"Foo::\" when you do that.\n" }, { "name": "\"exists $Foo::{Bar::}\" tests existence of a package", "content": "It was impossible to test for the existence of a package without actually creating it before.\nNow \"exists $Foo::{Bar::}\" can be used to test if the \"Foo::Bar\" namespace has been created.\n" }, { "name": "Better locale support", "content": "See perllocale.\n" }, { "name": "Experimental support for 64-bit platforms", "content": "Perl5 has always had 64-bit support on systems with 64-bit longs. Starting with 5.005, the\nbeginnings of experimental support for systems with 32-bit long and 64-bit 'long long'\nintegers has been added. If you add -DUSELONGLONG to your ccflags in config.sh (or\nmanually define it in perl.h) then perl will be built with 'long long' support. There will\nbe many compiler warnings, and the resultant perl may not work on all systems. There are\nmany other issues related to third-party extensions and libraries. This option exists to\nallow people to work on those issues.\n" }, { "name": "prototype() returns useful results on builtins", "content": "See \"prototype\" in perlfunc.\n" }, { "name": "Extended support for exception handling", "content": "\"die()\" now accepts a reference value, and $@ gets set to that value in exception traps.\nThis makes it possible to propagate exception objects. This is an undocumented experimental\nfeature.\n" }, { "name": "Re-blessing in DESTROY() supported for chaining DESTROY() methods", "content": "See \"Destructors\" in perlobj.\n" }, { "name": "All \"printf\" format conversions are handled internally", "content": "See \"printf\" in perlfunc.\n" }, { "name": "New \"INIT\" keyword", "content": "\"INIT\" subs are like \"BEGIN\" and \"END\", but they get run just before the perl runtime begins\nexecution. e.g., the Perl Compiler makes use of \"INIT\" blocks to initialize and resolve\npointers to XSUBs.\n" }, { "name": "New \"lock\" keyword", "content": "The \"lock\" keyword is the fundamental synchronization primitive in threaded perl. When\nthreads are not enabled, it is currently a noop.\n\nTo minimize impact on source compatibility this keyword is \"weak\", i.e., any user-defined\nsubroutine of the same name overrides it, unless a \"use Thread\" has been seen.\n" }, { "name": "New \"qr//\" operator", "content": "The \"qr//\" operator, which is syntactically similar to the other quote-like operators, is\nused to create precompiled regular expressions. This compiled form can now be explicitly\npassed around in variables, and interpolated in other regular expressions. See perlop.\n" }, { "name": "\"our\" is now a reserved word", "content": "Calling a subroutine with the name \"our\" will now provoke a warning when using the \"-w\"\nswitch.\n" }, { "name": "Tied arrays are now fully supported", "content": "See Tie::Array.\n" }, { "name": "Tied handles support is better", "content": "Several missing hooks have been added. There is also a new base class for TIEARRAY\nimplementations. See Tie::Array.\n" }, { "name": "4th argument to substr", "content": "substr() can now both return and replace in one operation. The optional 4th argument is the\nreplacement string. See \"substr\" in perlfunc.\n" }, { "name": "Negative LENGTH argument to splice", "content": "splice() with a negative LENGTH argument now work similar to what the LENGTH did for\nsubstr(). Previously a negative LENGTH was treated as 0. See \"splice\" in perlfunc.\n" }, { "name": "Magic lvalues are now more magical", "content": "When you say something like \"substr($x, 5) = \"hi\"\", the scalar returned by substr() is\nspecial, in that any modifications to it affect $x. (This is called a 'magic lvalue' because\nan 'lvalue' is something on the left side of an assignment.) Normally, this is exactly what\nyou would expect to happen, but Perl uses the same magic if you use substr(), pos(), or vec()\nin a context where they might be modified, like taking a reference with \"\\\" or as an argument\nto a sub that modifies @. In previous versions, this 'magic' only went one way, but now\nchanges to the scalar the magic refers to ($x in the above example) affect the magic lvalue\ntoo. For instance, this code now acts differently:\n\n$x = \"hello\";\nsub printit {\n$x = \"g'bye\";\nprint $[0], \"\\n\";\n}\nprintit(substr($x, 0, 5));\n\nIn previous versions, this would print \"hello\", but it now prints \"g'bye\".\n" }, { "name": "<> now reads in records", "content": "If $/ is a reference to an integer, or a scalar that holds an integer, <> will read in\nrecords instead of lines. For more info, see \"$/\" in perlvar.\n" }, { "name": "Supported Platforms", "content": "Configure has many incremental improvements. Site-wide policy for building perl can now be\nmade persistent, via Policy.sh. Configure also records the command-line arguments used in\nconfig.sh.\n" }, { "name": "New Platforms", "content": "BeOS is now supported. See README.beos.\n\nDOS is now supported under the DJGPP tools. See README.dos (installed as perldos on some\nsystems).\n\nMiNT is now supported. See README.mint.\n\nMPE/iX is now supported. See README.mpeix.\n\nMVS (aka OS390, aka Open Edition) is now supported. See README.os390 (installed as perlos390\non some systems).\n\nStratus VOS is now supported. See README.vos.\n" }, { "name": "Changes in existing support", "content": "Win32 support has been vastly enhanced. Support for Perl Object, a C++ encapsulation of\nPerl. GCC and EGCS are now supported on Win32. See README.win32, aka perlwin32.\n\nVMS configuration system has been rewritten. See README.vms (installed as READMEvms on some\nsystems).\n\nThe hints files for most Unix platforms have seen incremental improvements.\n" }, { "name": "Modules and Pragmata", "content": "" }, { "name": "New Modules", "content": "B Perl compiler and tools. See B.\n\nData::Dumper\nA module to pretty print Perl data. See Data::Dumper.\n\nDumpvalue\nA module to dump perl values to the screen. See Dumpvalue.\n\nErrno\nA module to look up errors more conveniently. See Errno.\n\nFile::Spec\nA portable API for file operations.\n\nExtUtils::Installed\nQuery and manage installed modules.\n\nExtUtils::Packlist\nManipulate .packlist files.\n\nFatal\nMake functions/builtins succeed or die.\n\nIPC::SysV\nConstants and other support infrastructure for System V IPC operations in perl.\n\nTest\nA framework for writing test suites.\n\nTie::Array\nBase class for tied arrays.\n\nTie::Handle\nBase class for tied handles.\n\nThread\nPerl thread creation, manipulation, and support.\n\nattrs\nSet subroutine attributes.\n\nfields\nCompile-time class fields.\n\nre Various pragmata to control behavior of regular expressions.\n" }, { "name": "Changes in existing modules", "content": "Benchmark\nYou can now run tests for x seconds instead of guessing the right number of tests to run.\n\nKeeps better time.\n\nCarp\nCarp has a new function cluck(). cluck() warns, like carp(), but also adds a stack\nbacktrace to the error message, like confess().\n\nCGI CGI has been updated to version 2.42.\n\nFcntl\nMore Fcntl constants added: FSETLK64, FSETLKW64, OLARGEFILE for large (more than 4G)\nfile access (the 64-bit support is not yet working, though, so no need to get overly\nexcited), Free/Net/OpenBSD locking behaviour flags FFLOCK, FPOSIX, Linux FSHLCK, and\nOACCMODE: the mask of ORDONLY, OWRONLY, and ORDWR.\n\nMath::Complex\nThe accessors methods Re, Im, arg, abs, rho, theta, methods can ($z->Re()) now also act\nas mutators ($z->Re(3)).\n\nMath::Trig\nA little bit of radial trigonometry (cylindrical and spherical) added, for example the\ngreat circle distance.\n\nPOSIX\nPOSIX now has its own platform-specific hints files.\n\nDBFile\nDBFile supports version 2.x of Berkeley DB. See \"ext/DBFile/Changes\".\n\nMakeMaker\nMakeMaker now supports writing empty makefiles, provides a way to specify that site\numask() policy should be honored. There is also better support for manipulation of\n.packlist files, and getting information about installed modules.\n\nExtensions that have both architecture-dependent and architecture-independent files are\nnow always installed completely in the architecture-dependent locations. Previously, the\nshareable parts were shared both across architectures and across perl versions and were\ntherefore liable to be overwritten with newer versions that might have subtle\nincompatibilities.\n\nCPAN\nSee perlmodinstall and CPAN.\n\nCwd Cwd::cwd is faster on most platforms.\n" }, { "name": "Utility Changes", "content": "\"h2ph\" and related utilities have been vastly overhauled.\n\n\"perlcc\", a new experimental front end for the compiler is available.\n\nThe crude GNU \"configure\" emulator is now called \"configure.gnu\" to avoid trampling on\n\"Configure\" under case-insensitive filesystems.\n\n\"perldoc\" used to be rather slow. The slower features are now optional. In particular,\ncase-insensitive searches need the \"-i\" switch, and recursive searches need \"-r\". You can\nset these switches in the \"PERLDOC\" environment variable to get the old behavior.\n" }, { "name": "Documentation Changes", "content": "Config.pm now has a glossary of variables.\n\nPorting/patching.pod has detailed instructions on how to create and submit patches for perl.\n\nperlport specifies guidelines on how to write portably.\n\nperlmodinstall describes how to fetch and install modules from \"CPAN\" sites.\n\nSome more Perl traps are documented now. See perltrap.\n\nperlopentut gives a tutorial on using open().\n\nperlreftut gives a tutorial on references.\n\nperlthrtut gives a tutorial on threads.\n" }, { "name": "New Diagnostics", "content": "Ambiguous call resolved as CORE::%s(), qualify as such or use &\n(W) A subroutine you have declared has the same name as a Perl keyword, and you have used\nthe name without qualification for calling one or the other. Perl decided to call the\nbuiltin because the subroutine is not imported.\n\nTo force interpretation as a subroutine call, either put an ampersand before the\nsubroutine name, or qualify the name with its package. Alternatively, you can import the\nsubroutine (or pretend that it's imported with the \"use subs\" pragma).\n\nTo silently interpret it as the Perl operator, use the \"CORE::\" prefix on the operator\n(e.g. \"CORE::log($x)\") or by declaring the subroutine to be an object method (see\n\"attrs\").\n\nBad index while coercing array into hash\n(F) The index looked up in the hash found as the 0'th element of a pseudo-hash is not\nlegal. Index values must be at 1 or greater. See perlref.\n\nBareword \"%s\" refers to nonexistent package\n(W) You used a qualified bareword of the form \"Foo::\", but the compiler saw no other uses\nof that namespace before that point. Perhaps you need to predeclare a package?\n\nCan't call method \"%s\" on an undefined value\n(F) You used the syntax of a method call, but the slot filled by the object reference or\npackage name contains an undefined value. Something like this will reproduce the error:\n\n$BADREF = 42;\nprocess $BADREF 1,2,3;\n$BADREF->process(1,2,3);\n\nCan't check filesystem of script \"%s\" for nosuid\n(P) For some reason you can't check the filesystem of the script for nosuid.\n\nCan't coerce array into hash\n(F) You used an array where a hash was expected, but the array has no information on how\nto map from keys to array indices. You can do that only with arrays that have a hash\nreference at index 0.\n\nCan't goto subroutine from an eval-string\n(F) The \"goto subroutine\" call can't be used to jump out of an eval \"string\". (You can\nuse it to jump out of an eval {BLOCK}, but you probably don't want to.)\n\nCan't localize pseudo-hash element\n(F) You said something like \"local $ar->{'key'}\", where $ar is a reference to a pseudo-\nhash. That hasn't been implemented yet, but you can get a similar effect by localizing\nthe corresponding array element directly: \"local $ar->[$ar->[0]{'key'}]\".\n\nCan't use %%! because Errno.pm is not available\n(F) The first time the %! hash is used, perl automatically loads the Errno.pm module. The\nErrno module is expected to tie the %! hash to provide symbolic names for $! errno\nvalues.\n\nCannot find an opnumber for \"%s\"\n(F) A string of a form \"CORE::word\" was given to prototype(), but there is no builtin\nwith the name \"word\".\n\nCharacter class syntax [. .] is reserved for future extensions\n(W) Within regular expression character classes ([]) the syntax beginning with \"[.\" and\nending with \".]\" is reserved for future extensions. If you need to represent those\ncharacter sequences inside a regular expression character class, just quote the square\nbrackets with the backslash: \"\\[.\" and \".\\]\".\n\nCharacter class syntax [: :] is reserved for future extensions\n(W) Within regular expression character classes ([]) the syntax beginning with \"[:\" and\nending with \":]\" is reserved for future extensions. If you need to represent those\ncharacter sequences inside a regular expression character class, just quote the square\nbrackets with the backslash: \"\\[:\" and \":\\]\".\n\nCharacter class syntax [= =] is reserved for future extensions\n(W) Within regular expression character classes ([]) the syntax beginning with \"[=\" and\nending with \"=]\" is reserved for future extensions. If you need to represent those\ncharacter sequences inside a regular expression character class, just quote the square\nbrackets with the backslash: \"\\[=\" and \"=\\]\".\n\n%s: Eval-group in insecure regular expression\n(F) Perl detected tainted data when trying to compile a regular expression that contains\nthe \"(?{ ... })\" zero-width assertion, which is unsafe. See \"(?{ code })\" in perlre, and\nperlsec.\n\n%s: Eval-group not allowed, use re 'eval'\n(F) A regular expression contained the \"(?{ ... })\" zero-width assertion, but that\nconstruct is only allowed when the \"use re 'eval'\" pragma is in effect. See \"(?{ code\n})\" in perlre.\n\n%s: Eval-group not allowed at run time\n(F) Perl tried to compile a regular expression containing the \"(?{ ... })\" zero-width\nassertion at run time, as it would when the pattern contains interpolated values. Since\nthat is a security risk, it is not allowed. If you insist, you may still do this by\nexplicitly building the pattern from an interpolated string at run time and using that in\nan eval(). See \"(?{ code })\" in perlre.\n\nExplicit blessing to '' (assuming package main)\n(W) You are blessing a reference to a zero length string. This has the effect of\nblessing the reference into the package main. This is usually not what you want.\nConsider providing a default target package, e.g. bless($ref, $p || 'MyPackage');\n\nIllegal hex digit ignored\n(W) You may have tried to use a character other than 0 - 9 or A - F in a hexadecimal\nnumber. Interpretation of the hexadecimal number stopped before the illegal character.\n\nNo such array field\n(F) You tried to access an array as a hash, but the field name used is not defined. The\nhash at index 0 should map all valid field names to array indices for that to work.\n\nNo such field \"%s\" in variable %s of type %s\n(F) You tried to access a field of a typed variable where the type does not know about\nthe field name. The field names are looked up in the %FIELDS hash in the type package at\ncompile time. The %FIELDS hash is usually set up with the 'fields' pragma.\n\nOut of memory during ridiculously large request\n(F) You can't allocate more than 2^31+\"small amount\" bytes. This error is most likely to\nbe caused by a typo in the Perl program. e.g., $arr[time] instead of $arr[$time].\n\nRange iterator outside integer range\n(F) One (or both) of the numeric arguments to the range operator \"..\" are outside the\nrange which can be represented by integers internally. One possible workaround is to\nforce Perl to use magical string increment by prepending \"0\" to your numbers.\n\nRecursive inheritance detected while looking for method '%s' %s\n(F) More than 100 levels of inheritance were encountered while invoking a method.\nProbably indicates an unintended loop in your inheritance hierarchy.\n\nReference found where even-sized list expected\n(W) You gave a single reference where Perl was expecting a list with an even number of\nelements (for assignment to a hash). This usually means that you used the anon hash\nconstructor when you meant to use parens. In any case, a hash requires key/value pairs.\n\n%hash = { one => 1, two => 2, }; # WRONG\n%hash = [ qw/ an anon array / ]; # WRONG\n%hash = ( one => 1, two => 2, ); # right\n%hash = qw( one 1 two 2 ); # also fine\n\nUndefined value assigned to typeglob\n(W) An undefined value was assigned to a typeglob, a la \"*foo = undef\". This does\nnothing. It's possible that you really mean \"undef *foo\".\n\nUse of reserved word \"%s\" is deprecated\n(D) The indicated bareword is a reserved word. Future versions of perl may use it as a\nkeyword, so you're better off either explicitly quoting the word in a manner appropriate\nfor its context of use, or using a different name altogether. The warning can be\nsuppressed for subroutine names by either adding a \"&\" prefix, or using a package\nqualifier, e.g. \"&our()\", or \"Foo::our()\".\n\nperl: warning: Setting locale failed.\n(S) The whole warning message will look something like:\n\nperl: warning: Setting locale failed.\nperl: warning: Please check that your locale settings:\nLCALL = \"EnUS\",\nLANG = (unset)\nare supported and installed on your system.\nperl: warning: Falling back to the standard locale (\"C\").\n\nExactly what were the failed locale settings varies. In the above the settings were that\nthe LCALL was \"EnUS\" and the LANG had no value. This error means that Perl detected\nthat you and/or your system administrator have set up the so-called variable system but\nPerl could not use those settings. This was not dead serious, fortunately: there is a\n\"default locale\" called \"C\" that Perl can and will use, the script will be run. Before\nyou really fix the problem, however, you will get the same error message each time you\nrun Perl. How to really fix the problem can be found in \"LOCALE PROBLEMS\" in perllocale.\n" }, { "name": "Obsolete Diagnostics", "content": "Can't mktemp()\n(F) The mktemp() routine failed for some reason while trying to process a -e switch.\nMaybe your /tmp partition is full, or clobbered.\n\nRemoved because -e doesn't use temporary files any more.\n\nCan't write to temp file for -e: %s\n(F) The write routine failed for some reason while trying to process a -e switch. Maybe\nyour /tmp partition is full, or clobbered.\n\nRemoved because -e doesn't use temporary files any more.\n\nCannot open temporary file\n(F) The create routine failed for some reason while trying to process a -e switch. Maybe\nyour /tmp partition is full, or clobbered.\n\nRemoved because -e doesn't use temporary files any more.\n\nregexp too big\n(F) The current implementation of regular expressions uses shorts as address offsets\nwithin a string. Unfortunately this means that if the regular expression compiles to\nlonger than 32767, it'll blow up. Usually when you want a regular expression this big,\nthere is a better way to do it with multiple statements. See perlre.\n" }, { "name": "Configuration Changes", "content": "You can use \"Configure -Uinstallusrbinperl\" which causes installperl to skip installing perl\nalso as /usr/bin/perl. This is useful if you prefer not to modify /usr/bin for some reason\nor another but harmful because many scripts assume to find Perl in /usr/bin/perl.\n" } ] }, "BUGS": { "content": "If you find what you think is a bug, you might check the headers of recently posted articles\nin the comp.lang.perl.misc newsgroup. There may also be information at\nhttp://www.perl.com/perl/ , the Perl Home Page.\n\nIf you believe you have an unreported bug, please run the perlbug program included with your\nrelease. Make sure you trim your bug down to a tiny but sufficient test case. Your bug\nreport, along with the output of \"perl -V\", will be sent off to to be\nanalysed by the Perl porting team.\n", "subsections": [] }, "SEE ALSO": { "content": "The Changes file for 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", "subsections": [] }, "HISTORY": { "content": "Written by Gurusamy Sarathy , with many contributions from The Perl\nPorters.\n\nSend omissions or corrections to .\n\n\n\nperl v5.34.0 2025-07-25 PERL5005DELTA(1)", "subsections": [] } } } }