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perl5005delta (1)


perl5005delta - what's new for perl5.005


Please see following description for synopsis


Perl Programmers Reference Guide                 PERL5005DELTA(1)

     perl5005delta - what's new for perl5.005

     This document describes differences between the 5.004
     release and this one.

About the new versioning system
     Perl is now developed on two tracks: a maintenance track
     that makes small, safe updates to released production
     versions with emphasis on compatibility; and a development
     track that pursues more aggressive evolution.  Maintenance
     releases (which should be considered production quality)
     have subversion numbers that run from 1 to 49, and
     development releases (which should be considered "alpha"
     quality) run from 50 to 99.

     Perl 5.005 is the combined product of the new dual-track
     development scheme.

Incompatible Changes
  WARNING:  This version is not binary compatible with Perl
     Starting with Perl 5.004_50 there were many deep and far-
     reaching changes to the language internals.  If you have
     dynamically loaded extensions that you built under perl
     5.003 or 5.004, you can continue to use them with 5.004, but
     you will need to rebuild and reinstall those extensions to
     use them 5.005.  See INSTALL for detailed instructions on
     how to upgrade.

  Default installation structure has changed
     The new Configure defaults are designed to allow a smooth
     upgrade from 5.004 to 5.005, but you should read INSTALL for
     a detailed discussion of the changes in order to adapt them
     to your system.

  Perl Source Compatibility
     When none of the experimental features are enabled, there
     should be very few user-visible Perl source compatibility

     If threads are enabled, then some caveats apply. @_ and $_
     become lexical variables.  The effect of this should be
     largely transparent to the user, but there are some boundary
     conditions under which user will need to be aware of the
     issues.  For example, "local(@_)" results in a "Can't
     localize lexical variable @_ ..." message.  This may be
     enabled in a future version.

     Some new keywords have been introduced.  These are generally
     expected to have very little impact on compatibility.  See

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     "New "INIT" keyword", "New "lock" keyword", and "New "qr//"

     Certain barewords are now reserved.  Use of these will
     provoke a warning if you have asked for them with the "-w"
     switch.  See ""our" is now a reserved word".

  C Source Compatibility
     There have been a large number of changes in the internals
     to support the new features in this release.

     o   Core sources now require ANSI C compiler

         An ANSI C compiler is now required to build perl.  See

     o   All Perl global variables must now be referenced with an
         explicit prefix

         All Perl global variables that are visible for use by
         extensions now have a "PL_" prefix.  New extensions
         should "not" refer to perl globals by their unqualified
         names.  To preserve sanity, we provide limited backward
         compatibility for globals that are being widely used
         like "sv_undef" and "na" (which should now be written as
         "PL_sv_undef", "PL_na" etc.)

         If you find that your XS extension does not compile
         anymore because a perl global is not visible, try adding
         a "PL_" prefix to the global and rebuild.

         It is strongly recommended that all functions in the
         Perl API that don't begin with "perl" be referenced with
         a "Perl_" prefix.  The bare function names without the
         "Perl_" prefix are supported with macros, but this
         support may cease in a future release.

         See perlapi.

     o   Enabling threads has source compatibility issues

         Perl built with threading enabled requires extensions to
         use the new "dTHR" macro to initialize the handle to
         access per-thread data.  If you see a compiler error
         that talks about the variable "thr" not being declared
         (when building a module that has XS code),  you need to
         add "dTHR;" at the beginning of the block that elicited
         the error.

         The API function "perl_get_sv("@",GV_ADD)" should be
         used instead of directly accessing perl globals as
         "GvSV(errgv)".  The API call is backward compatible with

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         existing perls and provides source compatibility with
         threading is enabled.

         See "C Source Compatibility" for more information.

  Binary Compatibility
     This version is NOT binary compatible with older versions.
     All extensions will need to be recompiled.  Further binaries
     built with threads enabled are incompatible with binaries
     built without.  This should largely be transparent to the
     user, as all binary incompatible configurations have their
     own unique architecture name, and extension binaries get
     installed at unique locations.  This allows coexistence of
     several configurations in the same directory hierarchy.  See

  Security fixes may affect compatibility
     A few taint leaks and taint omissions have been corrected.
     This may lead to "failure" of scripts that used to work with
     older versions.  Compiling with -DINCOMPLETE_TAINTS provides
     a perl with minimal amounts of changes to the tainting
     behavior.  But note that the resulting perl will have known

     Oneliners with the "-e" switch do not create temporary files

  Relaxed new mandatory warnings introduced in 5.004
     Many new warnings that were introduced in 5.004 have been
     made optional.  Some of these warnings are still present,
     but perl's new features make them less often a problem.  See
     "New Diagnostics".

     Perl has a new Social Contract for contributors.  See

     The license included in much of the Perl documentation has
     changed.  Most of the Perl documentation was previously
     under the implicit GNU General Public License or the
     Artistic License (at the user's choice).  Now much of the
     documentation unambiguously states the terms under which it
     may be distributed.  Those terms are in general much less
     restrictive than the GNU GPL.  See perl and the individual
     perl manpages listed therein.

Core Changes
     WARNING: Threading is considered an experimental feature.
     Details of the implementation may change without notice.
     There are known limitations and some bugs.  These are
     expected to be fixed in future versions.

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     See README.threads.

     WARNING: The Compiler and related tools are considered
     experimental.  Features may change without notice, and there
     are known limitations and bugs.  Since the compiler is fully
     external to perl, the default configuration will build and
     install it.

     The Compiler produces three different types of
     transformations of a perl program.  The C backend generates
     C code that captures perl's state just before execution
     begins.  It eliminates the compile-time overheads of the
     regular perl interpreter, but the run-time performance
     remains comparatively the same.  The CC backend generates
     optimized C code equivalent to the code path at run-time.
     The CC backend has greater potential for big optimizations,
     but only a few optimizations are implemented currently.  The
     Bytecode backend generates a platform independent bytecode
     representation of the interpreter's state just before
     execution.  Thus, the Bytecode back end also eliminates much
     of the compilation overhead of the interpreter.

     The compiler comes with several valuable utilities.

     "B::Lint" is an experimental module to detect and warn about
     suspicious code, especially the cases that the "-w" switch
     does not detect.

     "B::Deparse" can be used to demystify perl code, and
     understand how perl optimizes certain constructs.

     "B::Xref" generates cross reference reports of all
     definition and use of variables, subroutines and formats in
     a program.

     "B::Showlex" show the lexical variables used by a subroutine
     or file at a glance.

     "perlcc" is a simple frontend for compiling perl.

     See "ext/B/README", B, and the respective compiler modules.

  Regular Expressions
     Perl's regular expression engine has been seriously
     overhauled, and many new constructs are supported.  Several
     bugs have been fixed.

     Here is an itemized summary:

     Many new and improved optimizations
         Changes in the RE engine:

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                 Unneeded nodes removed;
                 Substrings merged together;
                 New types of nodes to process (SUBEXPR)* and similar expressions
                     quickly, used if the SUBEXPR has no side effects and matches
                     strings of the same length;
                 Better optimizations by lookup for constant substrings;
                 Better search for constants substrings anchored by $ ;

         Changes in Perl code using RE engine:

                 More optimizations to s/longer/short/;
                 study() was not working;
                 /blah/ may be optimized to an analogue of index() if $& $` $' not seen;
                 Unneeded copying of matched-against string removed;
                 Only matched part of the string is copying if $` $' were not seen;

     Many bug fixes
         Note that only the major bug fixes are listed here.  See
         Changes for others.

                 Backtracking might not restore start of $3.
                 No feedback if max count for * or + on "complex" subexpression
                     was reached, similarly (but at compile time) for {3,34567}
                 Primitive restrictions on max count introduced to decrease a
                     possibility of a segfault;
                 (ZERO-LENGTH)* could segfault;
                 (ZERO-LENGTH)* was prohibited;
                 Long REs were not allowed;
                 /RE/g could skip matches at the same position after a
                   zero-length match;

     New regular expression constructs
         The following new syntax elements are supported:

                 (?{ CODE })

     New operator for precompiled regular expressions
         See "New "qr//" operator".

     Other improvements

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                 Better debugging output (possibly with colors),
                     even from non-debugging Perl;
                 RE engine code now looks like C, not like assembler;
                 Behaviour of RE modifiable by `use re' directive;
                 Improved documentation;
                 Test suite significantly extended;
                 Syntax [:^upper:] etc., reserved inside character classes;

     Incompatible changes
                 (?i) localized inside enclosing group;
                 $( is not interpolated into RE any more;
                 /RE/g may match at the same position (with non-zero length)
                     after a zero-length match (bug fix).

     See perlre and perlop.

  Improved malloc()
     See banner at the beginning of "malloc.c" for details.

  Quicksort is internally implemented
     Perl now contains its own highly optimized qsort() routine.
     The new qsort() is resistant to inconsistent comparison
     functions, so Perl's "sort()" will not provoke coredumps any
     more when given poorly written sort subroutines.  (Some C
     library "qsort()"s that were being used before used to have
     this problem.)  In our testing, the new "qsort()" required
     the minimal number of pair-wise compares on average, among
     all known "qsort()" implementations.

     See "perlfunc/sort".

  Reliable signals
     Perl's signal handling is susceptible to random crashes,
     because signals arrive asynchronously, and the Perl runtime
     is not reentrant at arbitrary times.

     However, one experimental implementation of reliable signals
     is available when threads are enabled.  See
     "Thread::Signal".  Also see INSTALL for how to build a Perl
     capable of threads.

  Reliable stack pointers
     The internals now reallocate the perl stack only at
     predictable times.  In particular, magic calls never trigger
     reallocations of the stack, because all reentrancy of the
     runtime is handled using a "stack of stacks".  This should
     improve reliability of cached stack pointers in the
     internals and in XSUBs.

  More generous treatment of carriage returns
     Perl used to complain if it encountered literal carriage
     returns in scripts.  Now they are mostly treated like

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     whitespace within program text.  Inside string literals and
     here documents, literal carriage returns are ignored if they
     occur paired with linefeeds, or get interpreted as
     whitespace if they stand alone.  This behavior means that
     literal carriage returns in files should be avoided.  You
     can get the older, more compatible (but less generous)
     behavior by defining the preprocessor symbol
     "PERL_STRICT_CR" when building perl.  Of course, all this
     has nothing whatever to do with how escapes like "\r" are
     handled within strings.

     Note that this doesn't somehow magically allow you to keep
     all text files in DOS format.  The generous treatment only
     applies to files that perl itself parses.  If your C
     compiler doesn't allow carriage returns in files, you may
     still be unable to build modules that need a C compiler.

  Memory leaks
     "substr", "pos" and "vec" don't leak memory anymore when
     used in lvalue context.  Many small leaks that impacted
     applications that embed multiple interpreters have been

  Better support for multiple interpreters
     The build-time option "-DMULTIPLICITY" has had many of the
     details reworked.  Some previously global variables that
     should have been per-interpreter now are.  With care, this
     allows interpreters to call each other.  See the
     "PerlInterp" extension on CPAN.

  Behavior of local() on array and hash elements is now well-
     See "Temporary Values via local()" in perlsub.

  "%!" is transparently tied to the Errno module
     See perlvar, and Errno.

  Pseudo-hashes are supported
     See perlref.

  "EXPR foreach EXPR" is supported
     See perlsyn.

  Keywords can be globally overridden
     See perlsub.

  $^E is meaningful on Win32
     See perlvar.

  "foreach (1..1000000)" optimized
     "foreach (1..1000000)" is now optimized into a counting
     loop.  It does not try to allocate a 1000000-size list

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  "Foo::" can be used as implicitly quoted package name
     Barewords caused unintuitive behavior when a subroutine with
     the same name as a package happened to be defined.  Thus,
     "new Foo @args", use the result of the call to "Foo()"
     instead of "Foo" being treated as a literal.  The
     recommended way to write barewords in the indirect object
     slot is "new Foo:: @args".  Note that the method "new()" is
     called with a first argument of "Foo", not "Foo::" when you
     do that.

  "exists $Foo::{Bar::}" tests existence of a package
     It was impossible to test for the existence of a package
     without actually creating it before.  Now "exists
     $Foo::{Bar::}" can be used to test if the "Foo::Bar"
     namespace has been created.

  Better locale support
     See perllocale.

  Experimental support for 64-bit platforms
     Perl5 has always had 64-bit support on systems with 64-bit
     longs.  Starting with 5.005, the beginnings of experimental
     support for systems with 32-bit long and 64-bit 'long long'
     integers has been added.  If you add -DUSE_LONG_LONG to your
     ccflags in (or manually define it in perl.h) then
     perl will be built with 'long long' support.  There will be
     many compiler warnings, and the resultant perl may not work
     on all systems.  There are many other issues related to
     third-party extensions and libraries.  This option exists to
     allow people to work on those issues.

  prototype() returns useful results on builtins
     See "prototype" in perlfunc.

  Extended support for exception handling
     "die()" now accepts a reference value, and $@ gets set to
     that value in exception traps.  This makes it possible to
     propagate exception objects.  This is an undocumented
     experimental feature.

  Re-blessing in DESTROY() supported for chaining DESTROY()
     See "Destructors" in perlobj.

  All "printf" format conversions are handled internally
     See "printf" in perlfunc.

  New "INIT" keyword
     "INIT" subs are like "BEGIN" and "END", but they get run
     just before the perl runtime begins execution.  e.g., the

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     Perl Compiler makes use of "INIT" blocks to initialize and
     resolve pointers to XSUBs.

  New "lock" keyword
     The "lock" keyword is the fundamental synchronization
     primitive in threaded perl.  When threads are not enabled,
     it is currently a noop.

     To minimize impact on source compatibility this keyword is
     "weak", i.e., any user-defined subroutine of the same name
     overrides it, unless a "use Thread" has been seen.

  New "qr//" operator
     The "qr//" operator, which is syntactically similar to the
     other quote-like operators, is used to create precompiled
     regular expressions.  This compiled form can now be
     explicitly passed around in variables, and interpolated in
     other regular expressions.  See perlop.

  "our" is now a reserved word
     Calling a subroutine with the name "our" will now provoke a
     warning when using the "-w" switch.

  Tied arrays are now fully supported
     See Tie::Array.

  Tied handles support is better
     Several missing hooks have been added.  There is also a new
     base class for TIEARRAY implementations.  See Tie::Array.

  4th argument to substr
     substr() can now both return and replace in one operation.
     The optional 4th argument is the replacement string.  See
     "substr" in perlfunc.

  Negative LENGTH argument to splice
     splice() with a negative LENGTH argument now work similar to
     what the LENGTH did for substr().  Previously a negative
     LENGTH was treated as 0.  See "splice" in perlfunc.

  Magic lvalues are now more magical
     When you say something like "substr($x, 5) = "hi"", the
     scalar returned by substr() is special, in that any
     modifications to it affect $x.  (This is called a 'magic
     lvalue' because an 'lvalue' is something on the left side of
     an assignment.)  Normally, this is exactly what you would
     expect to happen, but Perl uses the same magic if you use
     substr(), pos(), or vec() in a context where they might be
     modified, like taking a reference with "\" or as an argument
     to a sub that modifies @_.  In previous versions, this
     'magic' only went one way, but now changes to the scalar the
     magic refers to ($x in the above example) affect the magic

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     lvalue too. For instance, this code now acts differently:

         $x = "hello";
         sub printit {
             $x = "g'bye";
             print $_[0], "\n";
         printit(substr($x, 0, 5));

     In previous versions, this would print "hello", but it now
     prints "g'bye".

  <> now reads in records
     If $/ is a reference to an integer, or a scalar that holds
     an integer, <> will read in records instead of lines. For
     more info, see "$/" in perlvar.

Supported Platforms
     Configure has many incremental improvements.  Site-wide
     policy for building perl can now be made persistent, via  Configure also records the command-line
     arguments used in

  New Platforms
     BeOS is now supported.  See README.beos.

     DOS is now supported under the DJGPP tools.  See README.dos
     (installed as perldos on some systems).

     MiNT is now supported.  See

     MPE/iX is now supported.  See README.mpeix.

     MVS (aka OS390, aka Open Edition) is now supported.  See
     README.os390 (installed as perlos390 on some systems).

     Stratus VOS is now supported.  See README.vos.

  Changes in existing support
     Win32 support has been vastly enhanced.  Support for Perl
     Object, a C++ encapsulation of Perl.  GCC and EGCS are now
     supported on Win32.  See README.win32, aka perlwin32.

     VMS configuration system has been rewritten.  See README.vms
     (installed as README_vms on some systems).

     The hints files for most Unix platforms have seen
     incremental improvements.

Modules and Pragmata
  New Modules
     B   Perl compiler and tools.  See B.

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         A module to pretty print Perl data.  See Data::Dumper.

         A module to dump perl values to the screen. See

         A module to look up errors more conveniently.  See

         A portable API for file operations.

         Query and manage installed modules.

         Manipulate .packlist files.

         Make functions/builtins succeed or die.

         Constants and other support infrastructure for System V
         IPC operations in perl.

         A framework for writing test suites.

         Base class for tied arrays.

         Base class for tied handles.

         Perl thread creation, manipulation, and support.

         Set subroutine attributes.

         Compile-time class fields.

     re  Various pragmata to control behavior of regular

  Changes in existing modules
         You can now run tests for x seconds instead of guessing
         the right number of tests to run.

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         Keeps better time.

         Carp has a new function cluck(). cluck() warns, like
         carp(), but also adds a stack backtrace to the error
         message, like confess().

     CGI CGI has been updated to version 2.42.

         More Fcntl constants added: F_SETLK64, F_SETLKW64,
         O_LARGEFILE for large (more than 4G) file access (the
         64-bit support is not yet working, though, so no need to
         get overly excited), Free/Net/OpenBSD locking behaviour
         flags F_FLOCK, F_POSIX, Linux F_SHLCK, and O_ACCMODE:
         the mask of O_RDONLY, O_WRONLY, and O_RDWR.

         The accessors methods Re, Im, arg, abs, rho, theta,
         methods can ($z->Re()) now also act as mutators

         A little bit of radial trigonometry (cylindrical and
         spherical) added, for example the great circle distance.

         POSIX now has its own platform-specific hints files.

         DB_File supports version 2.x of Berkeley DB.  See

         MakeMaker now supports writing empty makefiles, provides
         a way to specify that site umask() policy should be
         honored.  There is also better support for manipulation
         of .packlist files, and getting information about
         installed modules.

         Extensions that have both architecture-dependent and
         architecture-independent files are now always installed
         completely in the architecture-dependent locations.
         Previously, the shareable parts were shared both across
         architectures and across perl versions and were
         therefore liable to be overwritten with newer versions
         that might have subtle incompatibilities.

         See perlmodinstall and CPAN.

     Cwd Cwd::cwd is faster on most platforms.

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Utility Changes
     "h2ph" and related utilities have been vastly overhauled.

     "perlcc", a new experimental front end for the compiler is

     The crude GNU "configure" emulator is now called
     "configure.gnu" to avoid trampling on "Configure" under
     case-insensitive filesystems.

     "perldoc" used to be rather slow.  The slower features are
     now optional.  In particular, case-insensitive searches need
     the "-i" switch, and recursive searches need "-r".  You can
     set these switches in the "PERLDOC" environment variable to
     get the old behavior.

Documentation Changes now has a glossary of variables.

     Porting/patching.pod has detailed instructions on how to
     create and submit patches for perl.

     perlport specifies guidelines on how to write portably.

     perlmodinstall describes how to fetch and install modules
     from "CPAN" sites.

     Some more Perl traps are documented now.  See perltrap.

     perlopentut gives a tutorial on using open().

     perlreftut gives a tutorial on references.

     perlthrtut gives a tutorial on threads.

New Diagnostics
     Ambiguous call resolved as CORE::%s(), qualify as such or
         use &
         (W) A subroutine you have declared has the same name as
         a Perl keyword, and you have used the name without
         qualification for calling one or the other.  Perl
         decided to call the builtin because the subroutine is
         not imported.

         To force interpretation as a subroutine call, either put
         an ampersand before the subroutine name, or qualify the
         name with its package.  Alternatively, you can import
         the subroutine (or pretend that it's imported with the
         "use subs" pragma).

         To silently interpret it as the Perl operator, use the
         "CORE::" prefix on the operator (e.g. "CORE::log($x)")

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         or by declaring the subroutine to be an object method
         (see attrs).

     Bad index while coercing array into hash
         (F) The index looked up in the hash found as the 0'th
         element of a pseudo-hash is not legal.  Index values
         must be at 1 or greater.  See perlref.

     Bareword "%s" refers to nonexistent package
         (W) You used a qualified bareword of the form "Foo::",
         but the compiler saw no other uses of that namespace
         before that point.  Perhaps you need to predeclare a

     Can't call method "%s" on an undefined value
         (F) You used the syntax of a method call, but the slot
         filled by the object reference or package name contains
         an undefined value.  Something like this will reproduce
         the error:

             $BADREF = 42;
             process $BADREF 1,2,3;

     Can't check filesystem of script "%s" for nosuid
         (P) For some reason you can't check the filesystem of
         the script for nosuid.

     Can't coerce array into hash
         (F) You used an array where a hash was expected, but the
         array has no information on how to map from keys to
         array indices.  You can do that only with arrays that
         have a hash reference at index 0.

     Can't goto subroutine from an eval-string
         (F) The "goto subroutine" call can't be used to jump out
         of an eval "string".  (You can use it to jump out of an
         eval {BLOCK}, but you probably don't want to.)

     Can't localize pseudo-hash element
         (F) You said something like "local $ar->{'key'}", where
         $ar is a reference to a pseudo-hash.  That hasn't been
         implemented yet, but you can get a similar effect by
         localizing the corresponding array element directly:
         "local $ar->[$ar->[0]{'key'}]".

     Can't use %%! because is not available
         (F) The first time the %! hash is used, perl
         automatically loads the module. The Errno
         module is expected to tie the %! hash to provide
         symbolic names for $! errno values.

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     Cannot find an opnumber for "%s"
         (F) A string of a form "CORE::word" was given to
         prototype(), but there is no builtin with the name

     Character class syntax [. .] is reserved for future
         (W) Within regular expression character classes ([]) the
         syntax beginning with "[." and ending with ".]" is
         reserved for future extensions.  If you need to
         represent those character sequences inside a regular
         expression character class, just quote the square
         brackets with the backslash: "\[." and ".\]".

     Character class syntax [: :] is reserved for future
         (W) Within regular expression character classes ([]) the
         syntax beginning with "[:" and ending with ":]" is
         reserved for future extensions.  If you need to
         represent those character sequences inside a regular
         expression character class, just quote the square
         brackets with the backslash: "\[:" and ":\]".

     Character class syntax [= =] is reserved for future
         (W) Within regular expression character classes ([]) the
         syntax beginning with "[=" and ending with "=]" is
         reserved for future extensions.  If you need to
         represent those character sequences inside a regular
         expression character class, just quote the square
         brackets with the backslash: "\[=" and "=\]".

     %s: Eval-group in insecure regular expression
         (F) Perl detected tainted data when trying to compile a
         regular expression that contains the "(?{ ... })" zero-
         width assertion, which is unsafe.  See "(?{ code })" in
         perlre, and perlsec.

     %s: Eval-group not allowed, use re 'eval'
         (F) A regular expression contained the "(?{ ... })"
         zero-width assertion, but that construct is only allowed
         when the "use re 'eval'" pragma is in effect.  See "(?{
         code })" in perlre.

     %s: Eval-group not allowed at run time
         (F) Perl tried to compile a regular expression
         containing the "(?{ ... })" zero-width assertion at run
         time, as it would when the pattern contains interpolated
         values.  Since that is a security risk, it is not
         allowed.  If you insist, you may still do this by
         explicitly building the pattern from an interpolated
         string at run time and using that in an eval().  See

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         "(?{ code })" in perlre.

     Explicit blessing to '' (assuming package main)
         (W) You are blessing a reference to a zero length
         string.  This has the effect of blessing the reference
         into the package main.  This is usually not what you
         want.  Consider providing a default target package, e.g.
         bless($ref, $p || 'MyPackage');

     Illegal hex digit ignored
         (W) You may have tried to use a character other than 0 -
         9 or A - F in a hexadecimal number.  Interpretation of
         the hexadecimal number stopped before the illegal

     No such array field
         (F) You tried to access an array as a hash, but the
         field name used is not defined.  The hash at index 0
         should map all valid field names to array indices for
         that to work.

     No such field "%s" in variable %s of type %s
         (F) You tried to access a field of a typed variable
         where the type does not know about the field name.  The
         field names are looked up in the %FIELDS hash in the
         type package at compile time.  The %FIELDS hash is
         usually set up with the 'fields' pragma.

     Out of memory during ridiculously large request
         (F) You can't allocate more than 2^31+"small amount"
         bytes.  This error is most likely to be caused by a typo
         in the Perl program. e.g., $arr[time] instead of

     Range iterator outside integer range
         (F) One (or both) of the numeric arguments to the range
         operator ".."  are outside the range which can be
         represented by integers internally.  One possible
         workaround is to force Perl to use magical string
         increment by prepending "0" to your numbers.

     Recursive inheritance detected while looking for method '%s'
         (F) More than 100 levels of inheritance were encountered
         while invoking a method.  Probably indicates an
         unintended loop in your inheritance hierarchy.

     Reference found where even-sized list expected
         (W) You gave a single reference where Perl was expecting
         a list with an even number of elements (for assignment
         to a hash). This usually means that you used the anon
         hash constructor when you meant to use parens. In any

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         case, a hash requires key/value pairs.

             %hash = { one => 1, two => 2, };   # WRONG
             %hash = [ qw/ an anon array / ];   # WRONG
             %hash = ( one => 1, two => 2, );   # right
             %hash = qw( one 1 two 2 );                 # also fine

     Undefined value assigned to typeglob
         (W) An undefined value was assigned to a typeglob, a la
         "*foo = undef".  This does nothing.  It's possible that
         you really mean "undef *foo".

     Use of reserved word "%s" is deprecated
         (D) The indicated bareword is a reserved word.  Future
         versions of perl may use it as a keyword, so you're
         better off either explicitly quoting the word in a
         manner appropriate for its context of use, or using a
         different name altogether.  The warning can be
         suppressed for subroutine names by either adding a "&"
         prefix, or using a package qualifier, e.g. "&our()", or

     perl: warning: Setting locale failed.
         (S) The whole warning message will look something like:

                perl: warning: Setting locale failed.
                perl: warning: Please check that your locale settings:
                        LC_ALL = "En_US",
                        LANG = (unset)
                    are supported and installed on your system.
                perl: warning: Falling back to the standard locale ("C").

         Exactly what were the failed locale settings varies.  In
         the above the settings were that the LC_ALL was "En_US"
         and the LANG had no value.  This error means that Perl
         detected that you and/or your system administrator have
         set up the so-called variable system but Perl could not
         use those settings.  This was not dead serious,
         fortunately: there is a "default locale" called "C" that
         Perl can and will use, the script will be run.  Before
         you really fix the problem, however, you will get the
         same error message each time you run Perl.  How to
         really fix the problem can be found in "LOCALE PROBLEMS"
         in perllocale.

Obsolete Diagnostics
     Can't mktemp()
         (F) The mktemp() routine failed for some reason while
         trying to process a -e switch.  Maybe your /tmp
         partition is full, or clobbered.

         Removed because -e doesn't use temporary files any more.

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     Can't write to temp file for -e: %s
         (F) The write routine failed for some reason while
         trying to process a -e switch.  Maybe your /tmp
         partition is full, or clobbered.

         Removed because -e doesn't use temporary files any more.

     Cannot open temporary file
         (F) The create routine failed for some reason while
         trying to process a -e switch.  Maybe your /tmp
         partition is full, or clobbered.

         Removed because -e doesn't use temporary files any more.

     regexp too big
         (F) The current implementation of regular expressions
         uses shorts as address offsets within a string.
         Unfortunately this means that if the regular expression
         compiles to longer than 32767, it'll blow up.  Usually
         when you want a regular expression this big, there is a
         better way to do it with multiple statements.  See

Configuration Changes
     You can use "Configure -Uinstallusrbinperl" which causes
     installperl to skip installing perl also as /usr/bin/perl.
     This is useful if you prefer not to modify /usr/bin for some
     reason or another but harmful because many scripts assume to
     find Perl in /usr/bin/perl.

     If you find what you think is a bug, you might check the
     headers of recently posted articles in the
     comp.lang.perl.misc newsgroup.  There may also be
     information at , the Perl Home

     If you believe you have an unreported bug, please run the
     perlbug program included with your release.  Make sure you
     trim your bug down to a tiny but sufficient test case.  Your
     bug report, along with the output of "perl -V", will be sent
     off to <> to be analysed by the Perl porting

     See attributes(5) for descriptions of the following

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     |Availability   | runtime/perl-512 |
     |Stability      | Uncommitted      |
     The Changes file for exhaustive details on what changed.

     The INSTALL file for how to build Perl.

     The README file for general stuff.

     The Artistic and Copying files for copyright information.

     Written by Gurusamy Sarathy <>, with
     many contributions from The Perl Porters.

     Send omissions or corrections to <>.

     This software was built from source available at  The original
     community source was downloaded from

     Further information about this software can be found on the
     open source community website at

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