| =head1 NAME |
| |
| perl5005delta - 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<qrE<sol>E<sol>> 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<perlapi>. |
| |
| =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("@",GV_ADD)> 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 manpages 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<qrE<sol>E<sol>> 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<$/> is a reference to an integer, or a scalar that holds an integer, |
| <> will read in records instead of lines. For more info, see |
| L<perlvar/$E<sol>>. |
| |
| =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 F<README_vms> on some systems). |
| |
| The hints files for most Unix platforms have seen incremental improvements. |
| |
| =head1 Modules and Pragmata |
| |
| =head2 New Modules |
| |
| =over 4 |
| |
| =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 test suites. |
| |
| =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 4 |
| |
| =item Benchmark |
| |
| You can now run tests for I<x> seconds instead of guessing the right |
| number of tests to run. |
| |
| Keeps better time. |
| |
| =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 L<perlmodinstall> and L<CPAN>. |
| |
| =item Cwd |
| |
| Cwd::cwd is faster on most platforms. |
| |
| =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 4 |
| |
| =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' %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 4 |
| |
| =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 |