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diff --git a/gnu/usr.bin/perl/pod/perl5005delta.pod b/gnu/usr.bin/perl/pod/perl5005delta.pod new file mode 100644 index 00000000000..b133c0dd813 --- /dev/null +++ b/gnu/usr.bin/perl/pod/perl5005delta.pod @@ -0,0 +1,989 @@ +=head1 NAME + +perldelta - what's new for perl5.005 + +=head1 DESCRIPTION + +This document describes differences between the 5.004 release and this one. + +=head1 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 C<1> to C<49>, and +development releases (which should be considered "alpha" quality) run +from C<50> to C<99>. + +Perl 5.005 is the combined product of the new dual-track development +scheme. + +=head1 Incompatible Changes + +=head2 WARNING: This version 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 F<INSTALL> for detailed instructions on how to +upgrade. + +=head2 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 F<INSTALL> for a detailed +discussion of the changes in order to adapt them to your system. + +=head2 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. C<@_> and C<$_> 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, C<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 L<New C<INIT> keyword>, +L<New C<lock> keyword>, and L<New C<qr//> operator>. + +Certain barewords are now reserved. Use of these will provoke a warning +if you have asked for them with the C<-w> switch. +See L<C<our> is now a reserved word>. + +=head2 C Source Compatibility + +There have been a large number of changes in the internals to support +the new features in this release. + +=over 4 + +=item Core sources now require ANSI C compiler + +An ANSI C compiler is now B<required> to build perl. See F<INSTALL>. + +=item 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 C<PL_> prefix. New extensions should C<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 +C<sv_undef> and C<na> (which should now be written as C<PL_sv_undef>, +C<PL_na> etc.) + +If you find that your XS extension does not compile anymore because a +perl global is not visible, try adding a C<PL_> prefix to the global +and rebuild. + +It is strongly recommended that all functions in the Perl API that don't +begin with C<perl> be referenced with a C<Perl_> prefix. The bare function +names without the C<Perl_> prefix are supported with macros, but this +support may cease in a future release. + +See L<perlguts/"API LISTING">. + +=item Enabling threads has source compatibility issues + +Perl built with threading enabled requires extensions to use the new +C<dTHR> macro to initialize the handle to access per-thread data. +If you see a compiler error that talks about the variable C<thr> not +being declared (when building a module that has XS code), you need +to add C<dTHR;> at the beginning of the block that elicited the error. + +The API function C<perl_get_sv("@",FALSE)> should be used instead of +directly accessing perl globals as C<GvSV(errgv)>. The API call is +backward compatible with existing perls and provides source compatibility +with threading is enabled. + +See L<"C Source Compatibility"> for more information. + +=back + +=head2 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 F<INSTALL>. + +=head2 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 C<-e> switch do not create temporary files anymore. + +=head2 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 L<New Diagnostics>. + +=head2 Licensing + +Perl has a new Social Contract for contributors. See F<Porting/Contract>. + +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 L<perl> and the individual perl man pages listed +therein. + +=head1 Core Changes + + +=head2 Threads + +WARNING: Threading is considered an B<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. + +See F<README.threads>. + +=head2 Compiler + +WARNING: The Compiler and related tools are considered B<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. + +C<B::Lint> is an experimental module to detect and warn about suspicious +code, especially the cases that the C<-w> switch does not detect. + +C<B::Deparse> can be used to demystify perl code, and understand +how perl optimizes certain constructs. + +C<B::Xref> generates cross reference reports of all definition and use +of variables, subroutines and formats in a program. + +C<B::Showlex> show the lexical variables used by a subroutine or file +at a glance. + +C<perlcc> is a simple frontend for compiling perl. + +See C<ext/B/README>, L<B>, and the respective compiler modules. + +=head2 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: + +=over 4 + +=item Many new and improved optimizations + +Changes in the RE engine: + + 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; + +=item Many bug fixes + +Note that only the major bug fixes are listed here. See F<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; + +=item New regular expression constructs + +The following new syntax elements are supported: + + (?<=RE) + (?<!RE) + (?{ CODE }) + (?i-x) + (?i:RE) + (?(COND)YES_RE|NO_RE) + (?>RE) + \z + +=item New operator for precompiled regular expressions + +See L<New C<qr//> operator>. + +=item 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; + +=item 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). + +=back + +See L<perlre> and L<perlop>. + +=head2 Improved malloc() + +See banner at the beginning of C<malloc.c> for details. + +=head2 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 C<sort()> will +not provoke coredumps any more when given poorly written sort subroutines. +(Some C library C<qsort()>s that were being used before used to have this +problem.) In our testing, the new C<qsort()> required the minimal number +of pair-wise compares on average, among all known C<qsort()> implementations. + +See C<perlfunc/sort>. + +=head2 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 C<Thread::Signal>. Also see F<INSTALL> for +how to build a Perl capable of threads. + +=head2 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. + +=head2 More generous treatment of carriage returns + +Perl used to complain if it encountered literal carriage returns in +scripts. Now they are mostly treated like 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 +C<PERL_STRICT_CR> when building perl. Of course, all this has nothing +whatever to do with how escapes like C<\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. + +=head2 Memory leaks + +C<substr>, C<pos> and C<vec> don't leak memory anymore when used in lvalue +context. Many small leaks that impacted applications that embed multiple +interpreters have been fixed. + +=head2 Better support for multiple interpreters + +The build-time option C<-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 C<PerlInterp> extension on CPAN. + +=head2 Behavior of local() on array and hash elements is now well-defined + +See L<perlsub/"Temporary Values via local()">. + +=head2 C<%!> is transparently tied to the L<Errno> module + +See L<perlvar>, and L<Errno>. + +=head2 Pseudo-hashes are supported + +See L<perlref>. + +=head2 C<EXPR foreach EXPR> is supported + +See L<perlsyn>. + +=head2 Keywords can be globally overridden + +See L<perlsub>. + +=head2 C<$^E> is meaningful on Win32 + +See L<perlvar>. + +=head2 C<foreach (1..1000000)> optimized + +C<foreach (1..1000000)> is now optimized into a counting loop. It does +not try to allocate a 1000000-size list anymore. + +=head2 C<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, C<new Foo @args>, +use the result of the call to C<Foo()> instead of C<Foo> being treated +as a literal. The recommended way to write barewords in the indirect +object slot is C<new Foo:: @args>. Note that the method C<new()> is +called with a first argument of C<Foo>, not C<Foo::> when you do that. + +=head2 C<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 C<exists $Foo::{Bar::}> can be +used to test if the C<Foo::Bar> namespace has been created. + +=head2 Better locale support + +See L<perllocale>. + +=head2 Experimental support for 64-bit platforms + +Perl5 has always had 64-bit support on systems with 64-bit longs. +Starting with 5.005, the beginnings of experimental support for systems +with 32-bit long and 64-bit 'long long' integers has been added. +If you add -DUSE_LONG_LONG to your ccflags in config.sh (or manually +define it in perl.h) then perl will be built with 'long long' support. +There will be many compiler warnings, and the resultant perl may not +work on all systems. There are many other issues related to +third-party extensions and libraries. This option exists to allow +people to work on those issues. + +=head2 prototype() returns useful results on builtins + +See L<perlfunc/prototype>. + +=head2 Extended support for exception handling + +C<die()> now accepts a reference value, and C<$@> gets set to that +value in exception traps. This makes it possible to propagate +exception objects. This is an undocumented B<experimental> feature. + +=head2 Re-blessing in DESTROY() supported for chaining DESTROY() methods + +See L<perlobj/Destructors>. + +=head2 All C<printf> format conversions are handled internally + +See L<perlfunc/printf>. + +=head2 New C<INIT> keyword + +C<INIT> subs are like C<BEGIN> and C<END>, but they get run just before +the perl runtime begins execution. e.g., the Perl Compiler makes use of +C<INIT> blocks to initialize and resolve pointers to XSUBs. + +=head2 New C<lock> keyword + +The C<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 C<use Thread> +has been seen. + +=head2 New C<qr//> operator + +The C<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 L<perlop>. + +=head2 C<our> is now a reserved word + +Calling a subroutine with the name C<our> will now provoke a warning when +using the C<-w> switch. + +=head2 Tied arrays are now fully supported + +See L<Tie::Array>. + +=head2 Tied handles support is better + +Several missing hooks have been added. There is also a new base class for +TIEARRAY implementations. See L<Tie::Array>. + +=head2 4th argument to substr + +substr() can now both return and replace in one operation. The optional +4th argument is the replacement string. See L<perlfunc/substr>. + +=head2 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 L<perlfunc/splice>. + +=head2 Magic lvalues are now more magical + +When you say something like C<substr($x, 5) = "hi">, the scalar returned +by substr() is special, in that any modifications to it affect $x. +(This is called a 'magic lvalue' because an 'lvalue' is something on +the left side of an assignment.) Normally, this is exactly what you +would expect to happen, but Perl uses the same magic if you use substr(), +pos(), or vec() in a context where they might be modified, like taking +a reference with C<\> or as an argument to a sub that modifies C<@_>. +In previous versions, this 'magic' only went one way, but now changes +to the scalar the magic refers to ($x in the above example) affect the +magic 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". + +=head2 <> now reads in records + +If C<$/> is a reference to an integer, or a scalar that holds an integer, +<> will read in records instead of lines. For more info, see +L<perlvar/$/>. + +=head1 Supported Platforms + +Configure has many incremental improvements. Site-wide policy for building +perl can now be made persistent, via Policy.sh. Configure also records +the command-line arguments used in F<config.sh>. + +=head2 New Platforms + +BeOS is now supported. See F<README.beos>. + +DOS is now supported under the DJGPP tools. See F<README.dos> (installed +as L<perldos> on some systems). + +MiNT is now supported. See F<README.mint>. + +MPE/iX is now supported. See F<README.mpeix>. + +MVS (aka OS390, aka Open Edition) is now supported. See F<README.os390> +(installed as L<perlos390> on some systems). + +Stratus VOS is now supported. See F<README.vos>. + +=head2 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 F<README.win32>, aka L<perlwin32>. + +VMS configuration system has been rewritten. See F<README.vms> (installed +as L<README_vms> on some systems). + +The hints files for most Unix platforms have seen incremental improvements. + +=head1 Modules and Pragmata + +=head2 New Modules + +=over + +=item B + +Perl compiler and tools. See L<B>. + +=item Data::Dumper + +A module to pretty print Perl data. See L<Data::Dumper>. + +=item Dumpvalue + +A module to dump perl values to the screen. See L<Dumpvalue>. + +=item Errno + +A module to look up errors more conveniently. See L<Errno>. + +=item File::Spec + +A portable API for file operations. + +=item ExtUtils::Installed + +Query and manage installed modules. + +=item ExtUtils::Packlist + +Manipulate .packlist files. + +=item Fatal + +Make functions/builtins succeed or die. + +=item IPC::SysV + +Constants and other support infrastructure for System V IPC operations +in perl. + +=item Test + +A framework for writing testsuites. + +=item Tie::Array + +Base class for tied arrays. + +=item Tie::Handle + +Base class for tied handles. + +=item Thread + +Perl thread creation, manipulation, and support. + +=item attrs + +Set subroutine attributes. + +=item fields + +Compile-time class fields. + +=item re + +Various pragmata to control behavior of regular expressions. + +=back + +=head2 Changes in existing modules + +=over + +=item Benchmark + +You can now run tests for I<x> seconds instead of guessing the right +number of tests to run. + +=item Carp + +Carp has a new function cluck(). cluck() warns, like carp(), but also adds +a stack backtrace to the error message, like confess(). + +=item CGI + +CGI has been updated to version 2.42. + +=item Fcntl + +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. + +=item Math::Complex + +The accessors methods Re, Im, arg, abs, rho, theta, methods can +($z->Re()) now also act as mutators ($z->Re(3)). + +=item Math::Trig + +A little bit of radial trigonometry (cylindrical and spherical) added, +for example the great circle distance. + +=item POSIX + +POSIX now has its own platform-specific hints files. + +=item DB_File + +DB_File supports version 2.x of Berkeley DB. See C<ext/DB_File/Changes>. + +=item MakeMaker + +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. + +=item CPAN + +See <perlmodinstall> and L<CPAN>. + +=item Cwd + +Cwd::cwd is faster on most platforms. + +=item Benchmark + +Keeps better time. + +=back + +=head1 Utility Changes + +C<h2ph> and related utilities have been vastly overhauled. + +C<perlcc>, a new experimental front end for the compiler is available. + +The crude GNU C<configure> emulator is now called C<configure.gnu> to +avoid trampling on C<Configure> under case-insensitive filesystems. + +C<perldoc> used to be rather slow. The slower features are now optional. +In particular, case-insensitive searches need the C<-i> switch, and +recursive searches need C<-r>. You can set these switches in the +C<PERLDOC> environment variable to get the old behavior. + +=head1 Documentation Changes + +Config.pm now has a glossary of variables. + +F<Porting/patching.pod> has detailed instructions on how to create and +submit patches for perl. + +L<perlport> specifies guidelines on how to write portably. + +L<perlmodinstall> describes how to fetch and install modules from C<CPAN> +sites. + +Some more Perl traps are documented now. See L<perltrap>. + +L<perlopentut> gives a tutorial on using open(). + +L<perlreftut> gives a tutorial on references. + +L<perlthrtut> gives a tutorial on threads. + +=head1 New Diagnostics + +=over + +=item 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 C<use subs> pragma). + +To silently interpret it as the Perl operator, use the C<CORE::> prefix +on the operator (e.g. C<CORE::log($x)>) or by declaring the subroutine +to be an object method (see L<attrs>). + +=item 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 L<perlref>. + +=item Bareword "%s" refers to nonexistent package + +(W) You used a qualified bareword of the form C<Foo::>, but +the compiler saw no other uses of that namespace before that point. +Perhaps you need to predeclare a package? + +=item 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; + $BADREF->process(1,2,3); + +=item Can't check filesystem of script "%s" for nosuid + +(P) For some reason you can't check the filesystem of the script for nosuid. + +=item 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. + +=item 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.) + +=item Can't localize pseudo-hash element + +(F) You said something like C<< 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 -- C<< local $ar->[$ar->[0]{'key'}] >>. + +=item Can't use %%! because Errno.pm is not available + +(F) The first time the %! hash is used, perl automatically loads the +Errno.pm module. The Errno module is expected to tie the %! hash to +provide symbolic names for C<$!> errno values. + +=item Cannot find an opnumber for "%s" + +(F) A string of a form C<CORE::word> was given to prototype(), but +there is no builtin with the name C<word>. + +=item 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: "\[." and ".\]". + +=item 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: "\[:" and ":\]". + +=item 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: "\[=" and "=\]". + +=item %s: Eval-group in insecure regular expression + +(F) Perl detected tainted data when trying to compile a regular expression +that contains the C<(?{ ... })> zero-width assertion, which is unsafe. +See L<perlre/(?{ code })>, and L<perlsec>. + +=item %s: Eval-group not allowed, use re 'eval' + +(F) A regular expression contained the C<(?{ ... })> zero-width assertion, +but that construct is only allowed when the C<use re 'eval'> pragma is +in effect. See L<perlre/(?{ code })>. + +=item %s: Eval-group not allowed at run time + +(F) Perl tried to compile a regular expression containing the C<(?{ ... })> +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 L<perlre/(?{ code })>. + +=item 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, $p || 'MyPackage'); + +=item Illegal hex digit ignored + +(W) You may have tried to use a character other than 0 - 9 or A - F in a +hexadecimal number. Interpretation of the hexadecimal number stopped +before the illegal character. + +=item No such array field + +(F) You tried to access an array as a hash, but the field name used is +not defined. The hash at index 0 should map all valid field names to +array indices for that to work. + +=item No such field "%s" in variable %s of type %s + +(F) You tried to access a field of a typed variable where the type +does not know about the field name. The field names are looked up in +the %FIELDS hash in the type package at compile time. The %FIELDS hash +is usually set up with the 'fields' pragma. + +=item Out of memory during ridiculously large request + +(F) You can't allocate more than 2^31+"small amount" bytes. This error +is most likely to be caused by a typo in the Perl program. e.g., C<$arr[time]> +instead of C<$arr[$time]>. + +=item 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. + +=item Recursive inheritance detected while looking for method '%s' in package '%s' + +(F) More than 100 levels of inheritance were encountered while invoking a +method. Probably indicates an unintended loop in your inheritance hierarchy. + +=item 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 B<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 + +=item Undefined value assigned to typeglob + +(W) An undefined value was assigned to a typeglob, a la C<*foo = undef>. +This does nothing. It's possible that you really mean C<undef *foo>. + +=item 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 C<&> prefix, or using a package qualifier, +e.g. C<&our()>, or C<Foo::our()>. + +=item 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 L<perllocale/"LOCALE PROBLEMS">. + +=back + + +=head1 Obsolete Diagnostics + +=over + +=item Can't mktemp() + +(F) The mktemp() routine failed for some reason while trying to process +a B<-e> switch. Maybe your /tmp partition is full, or clobbered. + +Removed because B<-e> doesn't use temporary files any more. + +=item Can't write to temp file for B<-e>: %s + +(F) The write routine failed for some reason while trying to process +a B<-e> switch. Maybe your /tmp partition is full, or clobbered. + +Removed because B<-e> doesn't use temporary files any more. + +=item Cannot open temporary file + +(F) The create routine failed for some reason while trying to process +a B<-e> switch. Maybe your /tmp partition is full, or clobbered. + +Removed because B<-e> doesn't use temporary files any more. + +=item 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 L<perlre>. + +=back + +=head1 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. + +=head1 BUGS + +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 http://www.perl.com/perl/, the Perl +Home Page. + +If you believe you have an unreported bug, please run the B<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 C<perl -V>, will be sent off to <F<perlbug@perl.com>> to be +analysed by the Perl porting team. + +=head1 SEE ALSO + +The F<Changes> file for exhaustive details on what changed. + +The F<INSTALL> file for how to build Perl. + +The F<README> file for general stuff. + +The F<Artistic> and F<Copying> files for copyright information. + +=head1 HISTORY + +Written by Gurusamy Sarathy <F<gsar@activestate.com>>, with many contributions +from The Perl Porters. + +Send omissions or corrections to <F<perlbug@perl.com>>. + +=cut |