Seth Woolley's Man Viewer

perl5005delta(1) - perl5005delta - what's new for perl5.005 - man 1 perl5005delta

([section] manual, -k keyword, -K [section] search, -f whatis)
man plain no title

PERL5005DELTA(1)       Perl Programmers Reference Guide       PERL5005DELTA(1)

       perl5005delta - what's new for perl5.005

       This document describes differences between the 5.004 release and this

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

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

Incompatible Changes
       WARNING:  This version(1,3,5) is not binary compatible with Perl 5.004.

       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 instruc-
       tions 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(2,n,1 builtins) INSTALL for a detailed discussion
       of the changes in(1,8) 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 issues.

       If threads are enabled, then some caveats apply. @_ and $_ become lexi-
       cal 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(1,8) a
       "Can't localize lexical variable @_ ..." message.  This may be enabled
       in(1,8) a future version.

       Some new keywords have been introduced.  These are generally expected
       to have very little impact on compatibility.  See "New "INIT" keyword",
       "New "lock" keyword", and "New "qr//" operator".

       Certain barewords are now reserved.  Use of these will provoke a warn-
       ing if(3,n) 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(1,8) the internals to support
       the new features in(1,8) this release.

          Core sources now require ANSI C compiler

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

          All Perl global variables must now be referenced with an explicit

           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(1,8) 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(1,8) a future release.

           See perlapi.

          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(2,5) per-thread
           data.  If you see a compiler error(8,n) 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("@",FALSE)" should be used instead of
           directly accessing perl globals as "GvSV(errgv)".  The API call is
           backward compatible with existing perls and provides source compat-
           ibility with threading is enabled.

           See "C Source Compatibility" for more information.

       Binary Compatibility

       This version(1,3,5) is NOT binary compatible with older versions.  All exten-
       sions 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 configu-
       rations have their own unique architecture name, and extension binaries
       get installed at unique locations.  This allows coexistence of several
       configurations in(1,8) the same directory hierarchy.  See INSTALL.

       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 insecurities.

       Oneliners with the "-e" switch(1,n) do not create temporary files anymore.

       Relaxed new mandatory warnings introduced in(1,8) 5.004

       Many new warnings that were introduced in(1,8) 5.004 have been made
       optional.  Some of these warnings are still present, but perl's new
       features make them less(1,3) often a problem.  See "New Diagnostics".


       Perl has a new Social Contract for contributors.  See Porting/Contract.

       The license included in(1,8) 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(1,8) general much less(1,3)
       restrictive than the GNU GPL.  See perl and the individual perl man-
       pages listed therein.

Core Changes

       WARNING: Threading is considered an experimental feature.  Details of
       the implementation may change without notice.  There are known limita-
       tions and some bugs.  These are expected to be fixed in(1,8) future ver-

       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 con-
       figuration 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(1,n) 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(1,8) a program.

       "B::Showlex" show the lexical variables used by a subroutine or file(1,n) 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(1,8) the RE engine:

                   Unneeded nodes removed;
                   Substrings merged together;
                   New types of nodes to process (SUBEXPR)* and similar expressions
                       quickly, used if(3,n) 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(1,8) 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(3,n) $& $` $' not seen;
                   Unneeded copying of matched-against string(3,n) removed;
                   Only matched part of the string(3,n) is copying if(3,n) $` $' 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(3,n) max count for * or + on "complex" subexpression
                       was reached, similarly (but at compile time(1,2,n)) 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
                   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(1,3)()" will not provoke coredumps any more when given poorly written
       sort(1,3) 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(1,3)".

       Reliable signals

       Perl's signal(2,7) handling is susceptible to random(3,4,6) crashes, because sig-
       nals arrive asynchronously, and the Perl runtime is not reentrant at
       arbitrary times.

       However, one experimental implementation of reliable signals is avail-
       able 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(4,5) 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(1,8)
       the internals and in(1,8) XSUBs.

       More generous treatment of carriage returns

       Perl used to complain if(3,n) it encountered literal carriage returns in(1,8)
       scripts.  Now they are mostly treated like whitespace within program
       text.  Inside string(3,n) literals and here documents, literal carriage
       returns are ignored if(3,n) they occur paired with linefeeds, or get inter-
       preted as whitespace if(3,n) they stand alone.  This behavior means that
       literal carriage returns in(1,8) files should be avoided.  You can get the
       older, more compatible (but less(1,3) 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 han-
       dled within strings.

       Note that this doesn't somehow magically allow you to keep all text
       files in(1,8) DOS format.  The generous treatment only applies to files that
       perl itself parses.  If your C compiler doesn't allow carriage returns
       in(1,8) files, you may still be unable to build modules that need a C com-

       Memory leaks

       "substr", "pos" and "vec" don't leak memory anymore when used in(1,8) lvalue
       context.  Many small leaks that impacted applications that embed multi-
       ple interpreters have been fixed.

       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-defined

       See "Temporary Values via local()" in(1,8) 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 anymore.

       "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(1,2) barewords in(1,8) 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 actu-
       ally creating it before.  Now "exists $Foo::{Bar::}" can be used to
       test if(3,n) the "Foo::Bar" namespace has been created.

       Better locale(3,5,7) 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(1,8) (or manually
       define it in(1,8) 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(1,8) perlfunc.

       Extended support for exception handling

       "die()" now accepts a reference value, and $@ gets(3,n) set(7,n,1 builtins) to that value in(1,8)
       exception traps.  This makes it possible to propagate exception
       objects.  This is an undocumented(2,3) experimental feature.

       Re-blessing in(1,8) DESTROY() supported for chaining DESTROY() methods

       See "Destructors" in(1,8) perlobj.

       All "printf(1,3,1 builtins)" format conversions are handled internally

       See "printf(1,3,1 builtins)" in(1,8) 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 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(1,8)
       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(1,8) variables,
       and interpolated in(1,8) 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(1,8) one operation.  The
       optional 4th argument is the replacement string.  See "substr" in(1,8) perl-

       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(1,8) perlfunc.

       Magic lvalues are now more magical

       When you say something like "substr($x, 5) = "hi"", the scalar returned
       by substr() is special, in(1,8) that any modifications to it affect $x.
       (This is called a 'magic(4,5) lvalue' because an 'lvalue' is something on
       the left side of an assignment.)  Normally, this is exactly what you
       would expect to happen, but Perl uses the same magic(4,5) if(3,n) you use sub-
       str(), pos(), or vec() in(1,8) a context where they might be modified, like
       taking a reference with "\" or as an argument to a sub that modifies
       @_.  In previous versions, this 'magic(4,5)' only went one way, but now
       changes to the scalar the magic(4,5) refers to ($x in(1,8) the above example)
       affect the magic(4,5) lvalue too. For instance, this code now acts differ-

           $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

       <> now reads in(1,8) records

       If $/ is a reference to an integer, or a scalar that holds an integer,
       <> will read(2,n,1 builtins) in(1,8) records instead of lines. For more info(1,5,n), see "$/" in(1,8)

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(1,8)

       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(1,8) 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 improve-

Modules and Pragmata
       New Modules

       B   Perl compiler and tools.  See B.

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

           A module to dump perl values to the screen. See Dumpvalue.

           A module to look(1,8,3 Search::Dict) up errors more conveniently.  See Errno.

           A portable API for file(1,n) operations.

           Query and manage installed modules.

           Manipulate .packlist files.

           Make functions/builtins succeed or die.

           Constants and other support infrastructure for System V IPC opera-
           tions in(1,8) perl.

           A framework for writing testsuites.

           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 expressions.

       Changes in(1,8) existing modules

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

           Keeps better time.

           Carp has a new function cluck(). cluck() warns, like carp(), but
           also adds a stack backtrace to the error(8,n) message, like confess().

       CGI CGI has been updated to version(1,3,5) 2.42.

           More Fcntl constants added: F_SETLK64, F_SETLKW64, O_LARGEFILE for
           large (more than 4G) file(1,n) access(2,5) (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
           ($z->Re()) now also act as mutators ($z->Re(3)).

           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(1,3,5) 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(1,8) the archi-
           tecture-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.

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

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

       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(1,n), and recursive searches need "-r".  You can set(7,n,1 builtins) these switches
       in(1,8) 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(1,2) portably.

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

       Some more Perl traps are documented now.  See perltrap.

       perlopentut gives a tutorial on using open(2,3,n)().

       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 key-
           word, 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 amper-
           sand before the subroutine name, or qualify the name with its pack-
           age.  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)") 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(1,8) 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 com-
           piler saw no other uses of that namespace before that point.  Per-
           haps you need to predeclare a package?

       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(3,n)".  (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(1,2,n) 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.

       Cannot find an opnumber for "%s"
           (F) A string(3,n) of a form "CORE::word" was given to prototype(), but
           there is no builtin with the name "word".

       Character class syntax [. .] is reserved for future extensions
           (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 extensions
           (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 extensions
           (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(1,8) 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(1,8) 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(1,8) effect.  See "(?{ code })" in(1,8) perlre.

       %s: Eval-group not allowed at run time(1,2,n)
           (F) Perl tried to compile a regular expression containing the "(?{
           ... })" zero-width assertion at run time(1,2,n), as it would when the pat-
           tern contains interpolated values.  Since that is a security risk,
           it is not allowed.  If you insist, you may still do this by explic-
           itly building the pattern from an interpolated string(3,n) at run time(1,2,n)
           and using that in(1,8) an eval().  See "(?{ code })" in(1,8) 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(1,8) a hexadecimal number.  Interpretation of the hexadecimal number
           stopped before the illegal character.

       No such array field
           (F) You tried to access(2,5) 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(1,8) variable %s of type %s
           (F) You tried to access(2,5) a field of a typed variable where the type
           does not know about the field name.  The field names are looked up
           in(1,8) the %FIELDS hash in(1,8) the type package at compile time.  The
           %FIELDS hash is usually set(7,n,1 builtins) 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(8,n) is most likely to be caused by a typo in(1,8) the Perl program.
           e.g., $arr[time(1,2,n)] instead of $arr[$time(1,2,n)].

       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 magi-
           cal string(3,n) increment by prepending "0" to your numbers.

       Recursive inheritance detected while looking for method '%s' %s
           (F) More than 100 levels of inheritance were encountered while
           invoking a method.  Probably indicates an unintended loop in(1,8) 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 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 explic-
           itly quoting the word in(1,8) a manner appropriate for its context of
           use, or using a different name altogether.  The warning can be sup-
           pressed for subroutine names by either adding a "&" prefix, or
           using a package qualifier, e.g. "&our()", or "Foo::our()".

       perl: warning: Setting locale(3,5,7) failed.
           (S) The whole warning message will look(1,8,3 Search::Dict) something like:

                  perl: warning: Setting locale(3,5,7) failed.
                  perl: warning: Please check that your locale(3,5,7) settings:
                          LC_ALL = "En_US",
                          LANG = (unset)
                      are supported and installed on your system.
                  perl: warning: Falling back to the standard locale(3,5,7) ("C").

           Exactly what were the failed locale(3,5,7) settings varies.  In the above
           the settings were that the LC_ALL was "En_US" and the LANG had no
           value.  This error(8,n) means that Perl detected that you and/or your
           system administrator have set(7,n,1 builtins) up the so-called variable system but
           Perl could not use those settings.  This was not dead serious, for-
           tunately: there is a "default locale(3,5,7)" called "C" that Perl can and
           will use, the script will be run.  Before you really fix the prob-
           lem, however, you will get the same error(8,n) message each time(1,2,n) you run
           Perl.  How to really fix the problem can be found in(1,8) "LOCALE PROB-
           LEMS" in(1,8) perllocale.

Obsolete Diagnostics
       Can't mktemp(1,3)()
           (F) The mktemp(1,3)() routine failed for some reason while trying to
           process a -e switch.  Maybe your /tmp partition is full, or clob-

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

       Can't write(1,2) to temp file(1,n) for -e: %s
           (F) The write(1,2) routine failed for some reason while trying to
           process a -e switch.  Maybe your /tmp partition is full, or clob-

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

       Cannot open(2,3,n) temporary file(1,n)
           (F) The create routine failed for some reason while trying to
           process a -e switch.  Maybe your /tmp partition is full, or clob-

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

       regexp(3,n) too big
           (F) The current implementation of regular expressions uses shorts
           as address offsets within a string.  Unfortunately this means that
           if(3,n) 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 perlre.

Configuration Changes
       You can use "Configure -Uinstallusrbinperl" which causes installperl to
       skip installing perl also as /usr/bin/perl.  This is useful if(3,n) you pre-
       fer not to modify /usr/bin for some reason or another but harmful
       because many scripts assume to find Perl in(1,8) /usr/bin/perl.

       If you find what you think is a bug, you might check the headers of
       recently posted articles in(1,8) 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 pro-
       gram 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 team.

       The Changes file(1,n) for exhaustive details on what changed.

       The INSTALL file(1,n) for how to build Perl.

       The README file(1,n) for general stuff.

       The Artistic and Copying files for copyright information.

       Written by Gurusamy Sarathy <>, with many contribu-
       tions from The Perl Porters.

       Send omissions or corrections to <>.

perl v5.8.5                       2004-04-23                  PERL5005DELTA(1)

References for this manual (incoming links)