1N/Aperl5005delta - what's new for perl5.005
1N/AThis document describes differences between the 5.004 release and this one.
1N/A=head1 About the new versioning system
1N/APerl is now developed on two tracks: a maintenance track that makes
1N/Asmall, safe updates to released production versions with emphasis on
1N/Acompatibility; and a development track that pursues more aggressive
1N/Aevolution. Maintenance releases (which should be considered production
1N/Aquality) have subversion numbers that run from C<1> to C<49>, and
1N/Adevelopment releases (which should be considered "alpha" quality) run
1N/APerl 5.005 is the combined product of the new dual-track development
1N/A=head1 Incompatible Changes
1N/A=head2 WARNING: This version is not binary compatible with Perl 5.004.
1N/AStarting with Perl 5.004_50 there were many deep and far-reaching changes
1N/Ato the language internals. If you have dynamically loaded extensions
1N/Athat you built under perl 5.003 or 5.004, you can continue to use them
1N/Awith 5.004, but you will need to rebuild and reinstall those extensions
1N/Ato use them 5.005. See F<INSTALL> for detailed instructions on how to
1N/A=head2 Default installation structure has changed
1N/AThe new Configure defaults are designed to allow a smooth upgrade from
1N/A5.004 to 5.005, but you should read F<INSTALL> for a detailed
1N/Adiscussion of the changes in order to adapt them to your system.
1N/A=head2 Perl Source Compatibility
1N/AWhen none of the experimental features are enabled, there should be
1N/Avery few user-visible Perl source compatibility issues.
1N/AIf threads are enabled, then some caveats apply. C<@_> and C<$_> become
1N/Alexical variables. The effect of this should be largely transparent to
1N/Athe user, but there are some boundary conditions under which user will
1N/Aneed to be aware of the issues. For example, C<local(@_)> results in
1N/Aa "Can't localize lexical variable @_ ..." message. This may be enabled
1N/ASome new keywords have been introduced. These are generally expected to
1N/Ahave very little impact on compatibility. See L<New C<INIT> keyword>,
1N/AL<New C<lock> keyword>, and L<New C<qrE<sol>E<sol>> operator>.
1N/ACertain barewords are now reserved. Use of these will provoke a warning
1N/Aif you have asked for them with the C<-w> switch.
1N/ASee L<C<our> is now a reserved word>.
1N/A=head2 C Source Compatibility
1N/AThere have been a large number of changes in the internals to support
1N/Athe new features in this release.
1N/ACore sources now require ANSI C compiler
1N/AAn ANSI C compiler is now B<required> to build perl. See F<INSTALL>.
1N/AAll Perl global variables must now be referenced with an explicit prefix
1N/AAll Perl global variables that are visible for use by extensions now
1N/Ahave a C<PL_> prefix. New extensions should C<not> refer to perl globals
1N/Aby their unqualified names. To preserve sanity, we provide limited
1N/Abackward compatibility for globals that are being widely used like
1N/AC<sv_undef> and C<na> (which should now be written as C<PL_sv_undef>,
1N/AIf you find that your XS extension does not compile anymore because a
1N/Aperl global is not visible, try adding a C<PL_> prefix to the global
1N/AIt is strongly recommended that all functions in the Perl API that don't
1N/Abegin with C<perl> be referenced with a C<Perl_> prefix. The bare function
1N/Anames without the C<Perl_> prefix are supported with macros, but this
1N/Asupport may cease in a future release.
1N/AEnabling threads has source compatibility issues
1N/APerl built with threading enabled requires extensions to use the new
1N/AC<dTHR> macro to initialize the handle to access per-thread data.
1N/AIf you see a compiler error that talks about the variable C<thr> not
1N/Abeing declared (when building a module that has XS code), you need
1N/Ato add C<dTHR;> at the beginning of the block that elicited the error.
1N/AThe API function C<perl_get_sv("@",FALSE)> should be used instead of
1N/Adirectly accessing perl globals as C<GvSV(errgv)>. The API call is
1N/Abackward compatible with existing perls and provides source compatibility
1N/Awith threading is enabled.
1N/ASee L<"C Source Compatibility"> for more information.
1N/A=head2 Binary Compatibility
1N/AThis version is NOT binary compatible with older versions. All extensions
1N/Awill need to be recompiled. Further binaries built with threads enabled
1N/Aare incompatible with binaries built without. This should largely be
1N/Atransparent to the user, as all binary incompatible configurations have
1N/Atheir own unique architecture name, and extension binaries get installed at
1N/Aunique locations. This allows coexistence of several configurations in
1N/Athe same directory hierarchy. See F<INSTALL>.
1N/A=head2 Security fixes may affect compatibility
1N/AA few taint leaks and taint omissions have been corrected. This may lead
1N/Ato "failure" of scripts that used to work with older versions. Compiling
1N/Awith -DINCOMPLETE_TAINTS provides a perl with minimal amounts of changes
1N/Ato the tainting behavior. But note that the resulting perl will have
1N/AOneliners with the C<-e> switch do not create temporary files anymore.
1N/A=head2 Relaxed new mandatory warnings introduced in 5.004
1N/AMany new warnings that were introduced in 5.004 have been made
1N/Aoptional. Some of these warnings are still present, but perl's new
1N/Afeatures make them less often a problem. See L<New Diagnostics>.
1N/AThe license included in much of the Perl documentation has changed.
1N/AMost of the Perl documentation was previously under the implicit GNU
1N/AGeneral Public License or the Artistic License (at the user's choice).
1N/ANow much of the documentation unambiguously states the terms under which
1N/Ait may be distributed. Those terms are in general much less restrictive
1N/Athan the GNU GPL. See L<perl> and the individual perl manpages listed
1N/AWARNING: Threading is considered an B<experimental> feature. Details of the
1N/Aimplementation may change without notice. There are known limitations
1N/Aand some bugs. These are expected to be fixed in future versions.
1N/AWARNING: The Compiler and related tools are considered B<experimental>.
1N/AFeatures may change without notice, and there are known limitations
1N/Aand bugs. Since the compiler is fully external to perl, the default
1N/Aconfiguration will build and install it.
1N/AThe Compiler produces three different types of transformations of a
1N/Aperl program. The C backend generates C code that captures perl's state
1N/Ajust before execution begins. It eliminates the compile-time overheads
1N/Aof the regular perl interpreter, but the run-time performance remains
1N/Acomparatively the same. The CC backend generates optimized C code
1N/Aequivalent to the code path at run-time. The CC backend has greater
1N/Apotential for big optimizations, but only a few optimizations are
1N/Aimplemented currently. The Bytecode backend generates a platform
1N/Aindependent bytecode representation of the interpreter's state
1N/Ajust before execution. Thus, the Bytecode back end also eliminates
1N/Amuch of the compilation overhead of the interpreter.
1N/AThe compiler comes with several valuable utilities.
1N/AC<B::Lint> is an experimental module to detect and warn about suspicious
1N/Acode, especially the cases that the C<-w> switch does not detect.
1N/AC<B::Deparse> can be used to demystify perl code, and understand
1N/Ahow perl optimizes certain constructs.
1N/AC<B::Xref> generates cross reference reports of all definition and use
1N/Aof variables, subroutines and formats in a program.
1N/AC<B::Showlex> show the lexical variables used by a subroutine or file
1N/AC<perlcc> is a simple frontend for compiling perl.
1N/A=head2 Regular Expressions
1N/APerl's regular expression engine has been seriously overhauled, and
1N/Amany new constructs are supported. Several bugs have been fixed.
1N/AHere is an itemized summary:
1N/A=item Many new and improved optimizations
1N/AChanges in the RE engine:
1N/A Unneeded nodes removed;
1N/A Substrings merged together;
1N/A New types of nodes to process (SUBEXPR)* and similar expressions
1N/A quickly, used if the SUBEXPR has no side effects and matches
1N/A strings of the same length;
1N/A Better optimizations by lookup for constant substrings;
1N/A Better search for constants substrings anchored by $ ;
1N/AChanges in Perl code using RE engine:
1N/A study() was not working;
1N/A /blah/ may be optimized to an analogue of index() if $& $` $' not seen;
1N/A Unneeded copying of matched-against string removed;
1N/A Only matched part of the string is copying if $` $' were not seen;
1N/ANote that only the major bug fixes are listed here. See F<Changes> for others.
1N/A Backtracking might not restore start of $3.
1N/A No feedback if max count for * or + on "complex" subexpression
1N/A was reached, similarly (but at compile time) for {3,34567}
1N/A Primitive restrictions on max count introduced to decrease a
1N/A possibility of a segfault;
1N/A (ZERO-LENGTH)* could segfault;
1N/A (ZERO-LENGTH)* was prohibited;
1N/A Long REs were not allowed;
1N/A /RE/g could skip matches at the same position after a
1N/A=item New regular expression constructs
1N/AThe following new syntax elements are supported:
1N/A (?(COND)YES_RE|NO_RE)
1N/A=item New operator for precompiled regular expressions
1N/ASee L<New C<qrE<sol>E<sol>> operator>.
1N/A=item Other improvements
1N/A Better debugging output (possibly with colors),
1N/A even from non-debugging Perl;
1N/A RE engine code now looks like C, not like assembler;
1N/A Behaviour of RE modifiable by `use re' directive;
1N/A Improved documentation;
1N/A Test suite significantly extended;
1N/A Syntax [:^upper:] etc., reserved inside character classes;
1N/A=item Incompatible changes
1N/A (?i) localized inside enclosing group;
1N/A $( is not interpolated into RE any more;
1N/A /RE/g may match at the same position (with non-zero length)
1N/A after a zero-length match (bug fix).
1N/ASee L<perlre> and L<perlop>.
1N/A=head2 Improved malloc()
1N/A=head2 Quicksort is internally implemented
1N/APerl now contains its own highly optimized qsort() routine. The new qsort()
1N/Ais resistant to inconsistent comparison functions, so Perl's C<sort()> will
1N/Anot provoke coredumps any more when given poorly written sort subroutines.
1N/A(Some C library C<qsort()>s that were being used before used to have this
1N/Aproblem.) In our testing, the new C<qsort()> required the minimal number
1N/Aof pair-wise compares on average, among all known C<qsort()> implementations.
1N/A=head2 Reliable signals
1N/APerl's signal handling is susceptible to random crashes, because signals
1N/Aarrive asynchronously, and the Perl runtime is not reentrant at arbitrary
1N/AHowever, one experimental implementation of reliable signals is available
1N/Awhen threads are enabled. See C<Thread::Signal>. Also see F<INSTALL> for
1N/Ahow to build a Perl capable of threads.
1N/A=head2 Reliable stack pointers
1N/AThe internals now reallocate the perl stack only at predictable times.
1N/AIn particular, magic calls never trigger reallocations of the stack,
1N/Abecause all reentrancy of the runtime is handled using a "stack of stacks".
1N/AThis should improve reliability of cached stack pointers in the internals
1N/A=head2 More generous treatment of carriage returns
1N/APerl used to complain if it encountered literal carriage returns in
1N/Ascripts. Now they are mostly treated like whitespace within program text.
1N/AInside string literals and here documents, literal carriage returns are
1N/Aignored if they occur paired with linefeeds, or get interpreted as whitespace
1N/Aif they stand alone. This behavior means that literal carriage returns
1N/Ain files should be avoided. You can get the older, more compatible (but
1N/Aless generous) behavior by defining the preprocessor symbol
1N/AC<PERL_STRICT_CR> when building perl. Of course, all this has nothing
1N/Awhatever to do with how escapes like C<\r> are handled within strings.
1N/ANote that this doesn't somehow magically allow you to keep all text files
1N/Ain DOS format. The generous treatment only applies to files that perl
1N/Aitself parses. If your C compiler doesn't allow carriage returns in
1N/Afiles, you may still be unable to build modules that need a C compiler.
1N/AC<substr>, C<pos> and C<vec> don't leak memory anymore when used in lvalue
1N/Acontext. Many small leaks that impacted applications that embed multiple
1N/Ainterpreters have been fixed.
1N/A=head2 Better support for multiple interpreters
1N/AThe build-time option C<-DMULTIPLICITY> has had many of the details
1N/Areworked. Some previously global variables that should have been
1N/Aper-interpreter now are. With care, this allows interpreters to call
1N/Aeach other. See the C<PerlInterp> extension on CPAN.
1N/A=head2 Behavior of local() on array and hash elements is now well-defined
1N/ASee L<perlsub/"Temporary Values via local()">.
1N/A=head2 C<%!> is transparently tied to the L<Errno> module
1N/ASee L<perlvar>, and L<Errno>.
1N/A=head2 Pseudo-hashes are supported
1N/A=head2 C<EXPR foreach EXPR> is supported
1N/A=head2 Keywords can be globally overridden
1N/A=head2 C<$^E> is meaningful on Win32
1N/A=head2 C<foreach (1..1000000)> optimized
1N/AC<foreach (1..1000000)> is now optimized into a counting loop. It does
1N/Anot try to allocate a 1000000-size list anymore.
1N/A=head2 C<Foo::> can be used as implicitly quoted package name
1N/ABarewords caused unintuitive behavior when a subroutine with the same
1N/Aname as a package happened to be defined. Thus, C<new Foo @args>,
1N/Ause the result of the call to C<Foo()> instead of C<Foo> being treated
1N/Aas a literal. The recommended way to write barewords in the indirect
1N/Aobject slot is C<new Foo:: @args>. Note that the method C<new()> is
1N/Acalled with a first argument of C<Foo>, not C<Foo::> when you do that.
1N/A=head2 C<exists $Foo::{Bar::}> tests existence of a package
1N/AIt was impossible to test for the existence of a package without
1N/Aactually creating it before. Now C<exists $Foo::{Bar::}> can be
1N/Aused to test if the C<Foo::Bar> namespace has been created.
1N/A=head2 Better locale support
1N/A=head2 Experimental support for 64-bit platforms
1N/APerl5 has always had 64-bit support on systems with 64-bit longs.
1N/AStarting with 5.005, the beginnings of experimental support for systems
1N/Awith 32-bit long and 64-bit 'long long' integers has been added.
1N/AIf you add -DUSE_LONG_LONG to your ccflags in
config.sh (or manually
1N/Adefine it in
perl.h) then perl will be built with 'long long' support.
1N/AThere will be many compiler warnings, and the resultant perl may not
1N/Awork on all systems. There are many other issues related to
1N/Athird-party extensions and libraries. This option exists to allow
1N/Apeople to work on those issues.
1N/A=head2 prototype() returns useful results on builtins
1N/A=head2 Extended support for exception handling
1N/AC<die()> now accepts a reference value, and C<$@> gets set to that
1N/Avalue in exception traps. This makes it possible to propagate
1N/Aexception objects. This is an undocumented B<experimental> feature.
1N/A=head2 Re-blessing in DESTROY() supported for chaining DESTROY() methods
1N/A=head2 All C<printf> format conversions are handled internally
1N/A=head2 New C<INIT> keyword
1N/AC<INIT> subs are like C<BEGIN> and C<END>, but they get run just before
1N/Athe perl runtime begins execution.
e.g., the Perl Compiler makes use of
1N/AC<INIT> blocks to initialize and resolve pointers to XSUBs.
1N/A=head2 New C<lock> keyword
1N/AThe C<lock> keyword is the fundamental synchronization primitive
1N/Ain threaded perl. When threads are not enabled, it is currently a noop.
1N/ATo minimize impact on source compatibility this keyword is "weak",
i.e., any
1N/Auser-defined subroutine of the same name overrides it, unless a C<use Thread>
1N/A=head2 New C<qr//> operator
1N/AThe C<qr//> operator, which is syntactically similar to the other quote-like
1N/Aoperators, is used to create precompiled regular expressions. This compiled
1N/Aform can now be explicitly passed around in variables, and interpolated in
1N/Aother regular expressions. See L<perlop>.
1N/A=head2 C<our> is now a reserved word
1N/ACalling a subroutine with the name C<our> will now provoke a warning when
1N/Ausing the C<-w> switch.
1N/A=head2 Tied arrays are now fully supported
1N/A=head2 Tied handles support is better
1N/ASeveral missing hooks have been added. There is also a new base class for
1N/ATIEARRAY implementations. See L<Tie::Array>.
1N/A=head2 4th argument to substr
1N/Asubstr() can now both return and replace in one operation. The optional
1N/A=head2 Negative LENGTH argument to splice
1N/Asplice() with a negative LENGTH argument now work similar to what the
1N/ALENGTH did for substr(). Previously a negative LENGTH was treated as
1N/A=head2 Magic lvalues are now more magical
1N/AWhen you say something like C<substr($x, 5) = "hi">, the scalar returned
1N/Aby substr() is special, in that any modifications to it affect $x.
1N/A(This is called a 'magic lvalue' because an 'lvalue' is something on
1N/Athe left side of an assignment.) Normally, this is exactly what you
1N/Awould expect to happen, but Perl uses the same magic if you use substr(),
1N/Apos(), or vec() in a context where they might be modified, like taking
1N/Aa reference with C<\> or as an argument to a sub that modifies C<@_>.
1N/AIn previous versions, this 'magic' only went one way, but now changes
1N/Ato the scalar the magic refers to ($x in the above example) affect the
1N/Amagic lvalue too. For instance, this code now acts differently:
1N/A printit(substr($x, 0, 5));
1N/AIn previous versions, this would print "hello", but it now prints "g'bye".
1N/A=head2 <> now reads in records
1N/AIf C<$/> is a reference to an integer, or a scalar that holds an integer,
1N/A<> will read in records instead of lines. For more info, see
1N/A=head1 Supported Platforms
1N/AConfigure has many incremental improvements. Site-wide policy for building
1N/Aperl can now be made persistent, via
Policy.sh. Configure also records
1N/ADOS is now supported under the DJGPP tools. See F<
README.dos> (installed
1N/Aas L<perldos> on some systems).
1N/A(installed as L<perlos390> on some systems).
1N/A=head2 Changes in existing support
1N/AWin32 support has been vastly enhanced. Support for Perl Object, a C++
1N/Aencapsulation of Perl. GCC and EGCS are now supported on Win32.
1N/AVMS configuration system has been rewritten. See F<
README.vms> (installed
1N/Aas L<README_vms> on some systems).
1N/AThe hints files for most Unix platforms have seen incremental improvements.
1N/A=head1 Modules and Pragmata
1N/APerl compiler and tools. See L<B>.
1N/AA module to pretty print Perl data. See L<Data::Dumper>.
1N/AA module to dump perl values to the screen. See L<Dumpvalue>.
1N/AA module to look up errors more conveniently. See L<Errno>.
1N/AA portable API for file operations.
1N/A=item ExtUtils::Installed
1N/AQuery and manage installed modules.
1N/A=item ExtUtils::Packlist
1N/AManipulate .packlist files.
1N/AConstants and other support infrastructure for System V IPC operations
1N/AA framework for writing testsuites.
1N/ABase class for tied arrays.
1N/ABase class for tied handles.
1N/APerl thread creation, manipulation, and support.
1N/ASet subroutine attributes.
1N/ACompile-time class fields.
1N/AVarious pragmata to control behavior of regular expressions.
1N/A=head2 Changes in existing modules
1N/AYou can now run tests for I<x> seconds instead of guessing the right
1N/Anumber of tests to run.
1N/ACarp has a new function cluck(). cluck() warns, like carp(), but also adds
1N/Aa stack backtrace to the error message, like confess().
1N/ACGI has been updated to version 2.42.
1N/AMore Fcntl constants added: F_SETLK64, F_SETLKW64, O_LARGEFILE for
1N/Alarge (more than 4G) file access (the 64-bit support is not yet
1N/Alocking behaviour flags F_FLOCK, F_POSIX, Linux F_SHLCK, and
1N/AO_ACCMODE: the mask of O_RDONLY, O_WRONLY, and O_RDWR.
1N/AThe accessors methods Re, Im, arg, abs, rho, theta, methods can
1N/A($z->Re()) now also act as mutators ($z->Re(3)).
1N/AA little bit of radial trigonometry (cylindrical and spherical) added,
1N/Afor example the great circle distance.
1N/APOSIX now has its own platform-specific hints files.
1N/AMakeMaker now supports writing empty makefiles, provides a way to
1N/Aspecify that site umask() policy should be honored. There is also
1N/Abetter support for manipulation of .packlist files, and getting
1N/Ainformation about installed modules.
1N/AExtensions that have both architecture-dependent and
1N/Aarchitecture-independent files are now always installed completely in
1N/Athe architecture-dependent locations. Previously, the shareable parts
1N/Awere shared both across architectures and across perl versions and were
1N/Atherefore liable to be overwritten with newer versions that might have
1N/Asubtle incompatibilities.
1N/ASee L<perlmodinstall> and L<CPAN>.
1N/ACwd::cwd is faster on most platforms.
1N/A=head1 Utility Changes
1N/AC<h2ph> and related utilities have been vastly overhauled.
1N/AC<perlcc>, a new experimental front end for the compiler is available.
1N/Aavoid trampling on C<Configure> under case-insensitive filesystems.
1N/AC<perldoc> used to be rather slow. The slower features are now optional.
1N/AIn particular, case-insensitive searches need the C<-i> switch, and
1N/Arecursive searches need C<-r>. You can set these switches in the
1N/AC<PERLDOC> environment variable to get the old behavior.
1N/A=head1 Documentation Changes
1N/Asubmit patches for perl.
1N/AL<perlport> specifies guidelines on how to write portably.
1N/AL<perlmodinstall> describes how to fetch and install modules from C<CPAN>
1N/ASome more Perl traps are documented now. See L<perltrap>.
1N/AL<perlopentut> gives a tutorial on using open().
1N/AL<perlreftut> gives a tutorial on references.
1N/AL<perlthrtut> gives a tutorial on threads.
1N/A=head1 New Diagnostics
1N/A=item Ambiguous call resolved as CORE::%s(), qualify as such or use &
1N/A(W) A subroutine you have declared has the same name as a Perl keyword,
1N/Aand you have used the name without qualification for calling one or the
1N/Aother. Perl decided to call the builtin because the subroutine is
1N/ATo force interpretation as a subroutine call, either put an ampersand
1N/Abefore the subroutine name, or qualify the name with its package.
1N/AAlternatively, you can import the subroutine (or pretend that it's
1N/Aimported with the C<use subs> pragma).
1N/ATo silently interpret it as the Perl operator, use the C<CORE::> prefix
1N/Aon the operator (
e.g. C<CORE::log($x)>) or by declaring the subroutine
1N/Ato be an object method (see L<attrs>).
1N/A=item Bad index while coercing array into hash
1N/A(F) The index looked up in the hash found as the 0'th element of a
1N/Apseudo-hash is not legal. Index values must be at 1 or greater.
1N/A=item Bareword "%s" refers to nonexistent package
1N/A(W) You used a qualified bareword of the form C<Foo::>, but
1N/Athe compiler saw no other uses of that namespace before that point.
1N/APerhaps you need to predeclare a package?
1N/A=item Can't call method "%s" on an undefined value
1N/A(F) You used the syntax of a method call, but the slot filled by the
1N/Aobject reference or package name contains an undefined value.
1N/ASomething like this will reproduce the error:
1N/A process $BADREF 1,2,3;
1N/A $BADREF->process(1,2,3);
1N/A=item Can't check filesystem of script "%s" for nosuid
1N/A(P) For some reason you can't check the filesystem of the script for nosuid.
1N/A=item Can't coerce array into hash
1N/A(F) You used an array where a hash was expected, but the array has no
1N/Ainformation on how to map from keys to array indices. You can do that
1N/Aonly with arrays that have a hash reference at index 0.
1N/A=item Can't goto subroutine from an eval-string
1N/A(F) The "goto subroutine" call can't be used to jump out of an eval "string".
1N/A(You can use it to jump out of an eval {BLOCK}, but you probably don't want to.)
1N/A=item Can't localize pseudo-hash element
1N/A(F) You said something like C<< local $ar->{'key'} >>, where $ar is
1N/Aa reference to a pseudo-hash. That hasn't been implemented yet, but
1N/Ayou can get a similar effect by localizing the corresponding array
1N/Aelement directly -- C<< local $ar->[$ar->[0]{'key'}] >>.
1N/A(F) The first time the %! hash is used, perl automatically loads the
1N/AErrno.pm module. The Errno module is expected to tie the %! hash to
1N/Aprovide symbolic names for C<$!> errno values.
1N/A=item Cannot find an opnumber for "%s"
1N/A(F) A string of a form C<CORE::word> was given to prototype(), but
1N/Athere is no builtin with the name C<word>.
1N/A=item Character class syntax [. .] is reserved for future extensions
1N/A(W) Within regular expression character classes ([]) the syntax beginning
1N/Awith "[." and ending with ".]" is reserved for future extensions.
1N/AIf you need to represent those character sequences inside a regular
1N/Aexpression character class, just quote the square brackets with the
1N/Abackslash: "\[." and ".\]".
1N/A=item Character class syntax [: :] is reserved for future extensions
1N/A(W) Within regular expression character classes ([]) the syntax beginning
1N/Awith "[:" and ending with ":]" is reserved for future extensions.
1N/AIf you need to represent those character sequences inside a regular
1N/Aexpression character class, just quote the square brackets with the
1N/Abackslash: "\[:" and ":\]".
1N/A=item Character class syntax [= =] is reserved for future extensions
1N/A(W) Within regular expression character classes ([]) the syntax
1N/Abeginning with "[=" and ending with "=]" is reserved for future extensions.
1N/AIf you need to represent those character sequences inside a regular
1N/Aexpression character class, just quote the square brackets with the
1N/Abackslash: "\[=" and "=\]".
1N/A=item %s: Eval-group in insecure regular expression
1N/A(F) Perl detected tainted data when trying to compile a regular expression
1N/Athat contains the C<(?{ ... })> zero-width assertion, which is unsafe.
1N/ASee L<perlre/(?{ code })>, and L<perlsec>.
1N/A=item %s: Eval-group not allowed, use re 'eval'
1N/A(F) A regular expression contained the C<(?{ ... })> zero-width assertion,
1N/Abut that construct is only allowed when the C<use re 'eval'> pragma is
1N/Ain effect. See L<perlre/(?{ code })>.
1N/A=item %s: Eval-group not allowed at run time
1N/A(F) Perl tried to compile a regular expression containing the C<(?{ ... })>
1N/Azero-width assertion at run time, as it would when the pattern contains
1N/Ainterpolated values. Since that is a security risk, it is not allowed.
1N/AIf you insist, you may still do this by explicitly building the pattern
1N/Afrom an interpolated string at run time and using that in an eval().
1N/ASee L<perlre/(?{ code })>.
1N/A=item Explicit blessing to '' (assuming package main)
1N/A(W) You are blessing a reference to a zero length string. This has
1N/Athe effect of blessing the reference into the package main. This is
1N/Ausually not what you want. Consider providing a default target
1N/Apackage,
e.g. bless($ref, $p || 'MyPackage');
1N/A=item Illegal hex digit ignored
1N/A(W) You may have tried to use a character other than 0 - 9 or A - F in a
1N/Ahexadecimal number. Interpretation of the hexadecimal number stopped
1N/Abefore the illegal character.
1N/A=item No such array field
1N/A(F) You tried to access an array as a hash, but the field name used is
1N/Anot defined. The hash at index 0 should map all valid field names to
1N/Aarray indices for that to work.
1N/A=item No such field "%s" in variable %s of type %s
1N/A(F) You tried to access a field of a typed variable where the type
1N/Adoes not know about the field name. The field names are looked up in
1N/Athe %FIELDS hash in the type package at compile time. The %FIELDS hash
1N/Ais usually set up with the 'fields' pragma.
1N/A=item Out of memory during ridiculously large request
1N/A(F) You can't allocate more than 2^31+"small amount" bytes. This error
1N/Ais most likely to be caused by a typo in the Perl program.
e.g., C<$arr[time]>
1N/Ainstead of C<$arr[$time]>.
1N/A=item Range iterator outside integer range
1N/A(F) One (or both) of the numeric arguments to the range operator ".."
1N/Aare outside the range which can be represented by integers internally.
1N/AOne possible workaround is to force Perl to use magical string
1N/Aincrement by prepending "0" to your numbers.
1N/A=item Recursive inheritance detected while looking for method '%s' %s
1N/A(F) More than 100 levels of inheritance were encountered while invoking a
1N/Amethod. Probably indicates an unintended loop in your inheritance hierarchy.
1N/A=item Reference found where even-sized list expected
1N/A(W) You gave a single reference where Perl was expecting a list with
1N/Aan even number of elements (for assignment to a hash). This
1N/Ausually means that you used the anon hash constructor when you meant
1N/Ato use parens. In any case, a hash requires
key/value B<pairs>.
1N/A %hash = { one => 1, two => 2, }; # WRONG
1N/A %hash = [ qw/ an anon array / ]; # WRONG
1N/A %hash = ( one => 1, two => 2, ); # right
1N/A %hash = qw( one 1 two 2 ); # also fine
1N/A=item Undefined value assigned to typeglob
1N/A(W) An undefined value was assigned to a typeglob, a la C<*foo = undef>.
1N/AThis does nothing. It's possible that you really mean C<undef *foo>.
1N/A=item Use of reserved word "%s" is deprecated
1N/A(D) The indicated bareword is a reserved word. Future versions of perl
1N/Amay use it as a keyword, so you're better off either explicitly quoting
1N/Athe word in a manner appropriate for its context of use, or using a
1N/Adifferent name altogether. The warning can be suppressed for subroutine
1N/Anames by either adding a C<&> prefix, or using a package qualifier,
1N/A=item perl: warning: Setting locale failed.
1N/A(S) The whole warning message will look something like:
1N/A perl: warning: Setting locale failed.
1N/A perl: warning: Please check that your locale settings:
1N/A are supported and installed on your system.
1N/A perl: warning: Falling back to the standard locale ("C").
1N/AExactly what were the failed locale settings varies. In the above the
1N/Asettings were that the LC_ALL was "En_US" and the LANG had no value.
1N/AThis error means that Perl detected that you
and/or your system
1N/Aadministrator have set up the so-called variable system but Perl could
1N/Anot use those settings. This was not dead serious, fortunately: there
1N/Ais a "default locale" called "C" that Perl can and will use, the
1N/Ascript will be run. Before you really fix the problem, however, you
1N/Awill get the same error message each time you run Perl. How to really
1N/Afix the problem can be found in L<perllocale/"LOCALE PROBLEMS">.
1N/A=head1 Obsolete Diagnostics
1N/A(F) The mktemp() routine failed for some reason while trying to process
1N/Aa B<-e> switch. Maybe your /tmp partition is full, or clobbered.
1N/ARemoved because B<-e> doesn't use temporary files any more.
1N/A=item Can't write to temp file for B<-e>: %s
1N/A(F) The write routine failed for some reason while trying to process
1N/Aa B<-e> switch. Maybe your /tmp partition is full, or clobbered.
1N/ARemoved because B<-e> doesn't use temporary files any more.
1N/A=item Cannot open temporary file
1N/A(F) The create routine failed for some reason while trying to process
1N/Aa B<-e> switch. Maybe your /tmp partition is full, or clobbered.
1N/ARemoved because B<-e> doesn't use temporary files any more.
1N/A(F) The current implementation of regular expressions uses shorts as
1N/Aaddress offsets within a string. Unfortunately this means that if
1N/Athe regular expression compiles to longer than 32767, it'll blow up.
1N/AUsually when you want a regular expression this big, there is a better
1N/Away to do it with multiple statements. See L<perlre>.
1N/A=head1 Configuration Changes
1N/AYou can use "Configure -Uinstallusrbinperl" which causes installperl
1N/Aprefer not to modify
/usr/bin for some reason or another but harmful
1N/AIf you find what you think is a bug, you might check the headers of
1N/AIf you believe you have an unreported bug, please run the B<perlbug>
1N/Aprogram included with your release. Make sure you trim your bug down
1N/Ato a tiny but sufficient test case. Your bug report, along with the
1N/Aoutput of C<perl -V>, will be sent off to <F<perlbug@perl.com>> to be
1N/Aanalysed by the Perl porting team.
1N/AThe F<Changes> file for exhaustive details on what changed.
1N/AThe F<INSTALL> file for how to build Perl.
1N/AThe F<README> file for general stuff.
1N/AThe F<Artistic> and F<Copying> files for copyright information.
1N/AWritten by Gurusamy Sarathy <F<gsar@activestate.com>>, with many contributions
1N/Afrom The Perl Porters.
1N/ASend omissions or corrections to <F<perlbug@perl.com>>.