=head1 NAME
-perldelta - what's new for perl5.004
+perldelta - what's new for perl5.005
=head1 DESCRIPTION
-This document describes differences between the 5.003 release (as
-documented in I<Programming Perl>, second edition--the Camel Book) and
-this one.
+This document describes differences between the 5.004 release and this one.
-=head1 Supported Environments
+[XXX this needs more verbose summaries of the sub topics, instead of just
+the "See L<foo>." Scheduled for a second iteration. GSAR]
-Perl5.004 builds out of the box on Unix, Plan9, LynxOS, VMS, OS/2,
-QNX, AmigaOS, and Windows NT; once built on Windows NT, Perl runs
-on Windows 95 as well.
+=head1 About the new versioning system
-=head1 Core Changes
-
-Most importantly, many bugs were fixed. See the F<Changes>
-file in the distribution for details.
-
-=head2 Compilation option: Binary compatibility with 5.003
-
-There is a new Configure question that asks if you want to maintain
-binary compatibility with Perl 5.003. If you choose binary
-compatibility, you do not have to recompile your extensions, but you
-might have symbol conflicts if you embed Perl in another application,
-just as in the 5.003 release. By default, binary compatibility
-is preserved at the expense of symbol table pollution.
-
-=head2 $PERL5OPT environment variable
-
-You may now put Perl options in the $PERL5OPT environment variable.
-Unless Perl is running with taint checks, it will interpret this
-variable as if its contents had appeared on a "#!perl" line at the
-beginning of your script, except that hyphens are optional. PERL5OPT
-may only be used to set the following switches: B<-[DIMUdmw]>.
-
-=head2 Limitations on B<-M>, and B<-m>, and B<-T> options
-
-The C<-M> and C<-m> options are no longer allowed on the C<#!> line of
-a script. If a script needs a module, it should invoke it with the
-C<use> pragma.
-
-The B<-T> option is also forbidden on the C<#!> line of a script,
-unless it was present on the Perl command line. Due to the way C<#!>
-works, this usually means that B<-T> must be in the first argument.
-Thus:
-
- #!/usr/bin/perl -T -w
-
-will probably work for an executable script invoked as C<scriptname>,
-while:
-
- #!/usr/bin/perl -w -T
-
-will probably fail under the same conditions. (Non-Unix systems will
-probably not follow this rule.) But C<perl scriptname> is guaranteed
-to fail, since then there is no chance of B<-T> being found on the
-command line before it is found on the C<#!> line.
+=head1 Incompatible Changes
-=head2 More precise warnings
+=head2 WARNING: This version is not binary compatible with Perl 5.004.
-If you removed the B<-w> option from your Perl 5.003 scripts because it
-made Perl too verbose, we recommend that you try putting it back when
-you upgrade to Perl 5.004. Each new perl version tends to remove some
-undesirable warnings, while adding new warnings that may catch bugs in
-your scripts.
+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 L<INSTALL> for detailed instructions on how to
+upgrade.
-=head2 Deprecated: Inherited C<AUTOLOAD> for non-methods
+=head2 Default installation structure has changed
-Before Perl 5.004, C<AUTOLOAD> functions were looked up as methods
-(using the C<@ISA> hierarchy), even when the function to be autoloaded
-was called as a plain function (e.g. C<Foo::bar()>), not a method
-(e.g. C<Foo-E<gt>bar()> or C<$obj-E<gt>bar()>).
+The new Configure defaults are designed to allow a smooth upgrade from
+5.004 to 5.005, but you should read L<INSTALL> for a detailed
+discussion of the changes in order to adapt them to your system.
-Perl 5.005 will use method lookup only for methods' C<AUTOLOAD>s.
-However, there is a significant base of existing code that may be using
-the old behavior. So, as an interim step, Perl 5.004 issues an optional
-warning when a non-method uses an inherited C<AUTOLOAD>.
+=head2 Perl Source Compatibility
-The simple rule is: Inheritance will not work when autoloading
-non-methods. The simple fix for old code is: In any module that used to
-depend on inheriting C<AUTOLOAD> for non-methods from a base class named
-C<BaseClass>, execute C<*AUTOLOAD = \&BaseClass::AUTOLOAD> during startup.
+When none of the experimental features are enabled, there should be
+no user-visible Perl source compatibility issue.
-=head2 Subroutine arguments created only when they're modified
+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. [XXX Add e.g. here.]
-In Perl 5.004, nonexistent array and hash elements used as subroutine
-parameters are brought into existence only if they are actually
-assigned to (via C<@_>).
+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>.
-Earlier versions of Perl vary in their handling of such arguments.
-Perl versions 5.002 and 5.003 always brought them into existence.
-Perl versions 5.000, 5.001, and 5.002 brought them into existence only
-if they were not the first argument (which was almost certainly a
-bug). Earlier versions of Perl never brought them into existence.
+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>.
-For example, given this code:
+=head2 C Source Compatibility
- undef @a; undef %a;
- sub show { print $_[0] };
- sub change { $_[0]++ };
- show($a[2]);
- change($a{b});
+=item Core sources now require ANSI C compiler
-After this code executes in Perl 5.004, $a{b} exists but $a[2] does
-not. In Perl 5.002 and 5.003, both $a{b} and $a[2] would have existed
-(but $a[2]'s value would have been undefined).
+=item Enabling threads has source compatibility issues
-=head2 Group vector changeable with C<$)>
+=head2 Binary Compatibility
-The C<$)> special variable has always (well, in Perl 5, at least)
-reflected not only the current effective group, but also the group list
-as returned by the C<getgroups()> C function (if there is one).
-However, until this release, there has not been a way to call the
-C<setgroups()> C function from Perl.
+This version is NOT binary compatible with older versions. All extensions
+will need to be recompiled.
-In Perl 5.004, assigning to C<$)> is exactly symmetrical with examining
-it: The first number in its string value is used as the effective gid;
-if there are any numbers after the first one, they are passed to the
-C<setgroups()> C function (if there is one).
+=head2 Security fixes may affect compatibility
-=head2 Fixed parsing of $$<digit>, &$<digit>, etc.
+A few taint leaks and taint omissions have been corrected. This may lead
+to "failure" of scripts that used to work with older versions. Compiling
+with -DINCOMPLETE_TAINTS provides a perl with minimal amounts of changes
+to the tainting behavior. But note that the resulting perl will have
+known insecurities.
-Perl versions before 5.004 misinterpreted any type marker followed by
-"$" and a digit. For example, "$$0" was incorrectly taken to mean
-"${$}0" instead of "${$0}". This bug is (mostly) fixed in Perl 5.004.
+Oneliners with the C<-e> switch do not create temporary files anymore.
-However, the developers of Perl 5.004 could not fix this bug completely,
-because at least two widely-used modules depend on the old meaning of
-"$$0" in a string. So Perl 5.004 still interprets "$$<digit>" in the
-old (broken) way inside strings; but it generates this message as a
-warning. And in Perl 5.005, this special treatment will cease.
+=head2 Relaxed new mandatory warnings introduced in 5.004
-=head2 No resetting of $. on implicit close
+Many new warnings that were introduced in 5.004 have been made
+optional. Some of these warnings are still present, but perl's new
+features make them less often a problem. See L<New Diagnostics>.
-The documentation for Perl 5.0 has always stated that C<$.> is I<not>
-reset when an already-open file handle is reopened with no intervening
-call to C<close>. Due to a bug, perl versions 5.000 through 5.003
-I<did> reset C<$.> under that circumstance; Perl 5.004 does not.
+=head2 Licensing
-=head2 C<wantarray> may return undef
+Perl has a new Social Contract for contributors. See F<Porting/Contract>.
-The C<wantarray> operator returns true if a subroutine is expected to
-return a list, and false otherwise. In Perl 5.004, C<wantarray> can
-also return the undefined value if a subroutine's return value will
-not be used at all, which allows subroutines to avoid a time-consuming
-calculation of a return value if it isn't going to be used.
+The license included in much of the Perl documentation has changed.
+[XXX See where?]
-=head2 Changes to tainting checks
-
-A bug in previous versions may have failed to detect some insecure
-conditions when taint checks are turned on. (Taint checks are used
-in setuid or setgid scripts, or when explicitly turned on with the
-C<-T> invocation option.) Although it's unlikely, this may cause a
-previously-working script to now fail -- which should be construed
-as a blessing, since that indicates a potentially-serious security
-hole was just plugged.
-
-=head2 New Opcode module and revised Safe module
-
-A new Opcode module supports the creation, manipulation and
-application of opcode masks. The revised Safe module has a new API
-and is implemented using the new Opcode module. Please read the new
-Opcode and Safe documentation.
-
-=head2 Embedding improvements
-
-In older versions of Perl it was not possible to create more than one
-Perl interpreter instance inside a single process without leaking like a
-sieve and/or crashing. The bugs that caused this behavior have all been
-fixed. However, you still must take care when embedding Perl in a C
-program. See the updated perlembed manpage for tips on how to manage
-your interpreters.
-
-=head2 Internal change: FileHandle class based on IO::* classes
-
-File handles are now stored internally as type IO::Handle. The
-FileHandle module is still supported for backwards compatibility, but
-it is now merely a front end to the IO::* modules -- specifically,
-IO::Handle, IO::Seekable, and IO::File. We suggest, but do not
-require, that you use the IO::* modules in new code.
-
-In harmony with this change, C<*GLOB{FILEHANDLE}> is now a
-backward-compatible synonym for C<*GLOB{IO}>.
-
-=head2 Internal change: PerlIO abstraction interface
+=head1 Core Changes
-It is now possible to build Perl with AT&T's sfio IO package
-instead of stdio. See L<perlapio> for more details, and
-the F<INSTALL> file for how to use it.
-=head2 New and changed syntax
+=head2 Threads
-=over
+WARNING: Threading is considered an experimental feature. Details of the
+implementation may change without notice. There are known limitations
+and and some bugs.
-=item $coderef->(PARAMS)
+See L<README.threads>.
-A subroutine reference may now be suffixed with an arrow and a
-(possibly empty) parameter list. This syntax denotes a call of the
-referenced subroutine, with the given parameters (if any).
+=head2 Compiler
-This new syntax follows the pattern of S<C<$hashref-E<gt>{FOO}>> and
-S<C<$aryref-E<gt>[$foo]>>: You may now write S<C<&$subref($foo)>> as
-S<C<$subref-E<gt>($foo)>>. All of these arrow terms may be chained;
-thus, S<C<&{$table-E<gt>{FOO}}($bar)>> may now be written
-S<C<$table-E<gt>{FOO}-E<gt>($bar)>>.
+WARNING: The Compiler and related tools are considered experimental.
+Features may change without notice, and there are known limitations
+and bugs.
-=back
+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
+equivivalent 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.
-=head2 New and changed builtin constants
+The compiler comes with several valuable utilities.
-=over
+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.
-=item __PACKAGE__
+C<B::Deparse> can be used to demystify perl code, and understand
+how perl optimizes certain constructs.
-The current package name at compile time, or the undefined value if
-there is no current package (due to a C<package;> directive). Like
-C<__FILE__> and C<__LINE__>, C<__PACKAGE__> does I<not> interpolate
-into strings.
+C<B::Xref> generates cross reference reports of all definition and use
+of variables, subroutines and formats in a program.
-=back
+C<B::Showlex> show the lexical variables used by a subroutine or file
+at a glance.
-=head2 New and changed builtin variables
+C<perlcc> is a simple frontend for compiling perl.
-=over
+See C<ext/B/README>.
-=item $^E
+=head2 Regular Expressions
-Extended error message on some platforms. (Also known as
-$EXTENDED_OS_ERROR if you C<use English>).
+See L<perlre> and L<perlop>.
-=item $^H
+=head2 Improved malloc()
-The current set of syntax checks enabled by C<use strict>. See the
-documentation of C<strict> for more details. Not actually new, but
-newly documented.
-Because it is intended for internal use by Perl core components,
-there is no C<use English> long name for this variable.
+See banner at the beginning of C<malloc.c> for details.
-=item $^M
+=head2 Quicksort is internally implemented
-By default, running out of memory it is not trappable. However, if
-compiled for this, Perl may use the contents of C<$^M> as an emergency
-pool after die()ing with this message. Suppose that your Perl were
-compiled with -DEMERGENCY_SBRK and used Perl's malloc. Then
+See C<perlfunc/sort>.
- $^M = 'a' x (1<<16);
+=head2 Reliable signals
-would allocate a 64K buffer for use when in emergency.
-See the F<INSTALL> file for information on how to enable this option.
-As a disincentive to casual use of this advanced feature,
-there is no C<use English> long name for this variable.
+Two kinds.
-=back
+Via C<Thread::Signal>.
-=head2 New and changed builtin functions
+Via switched runtime op loop. [XXX Not yet available.]
-=over
+=head2 Reliable stack pointers
-=item delete on slices
+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.
-This now works. (e.g. C<delete @ENV{'PATH', 'MANPATH'}>)
+=head2 Behavior of local() on composites is now well-defined
-=item flock
+See L<perlfunc/local>.
-is now supported on more platforms, prefers fcntl to lockf when
-emulating, and always flushes before (un)locking.
+=head2 C<%!> is transparently tied to the L<Errno> module
-=item printf and sprintf
+See L<perlvar>, and L<Errno>.
-Perl now implements these functions itself; it doesn't use the C
-library function sprintf() any more, except for floating-point
-numbers, and even then only known flags are allowed. As a result, it
-is now possible to know which conversions and flags will work, and
-what they will do.
+=head2 Pseudo-hashes are supported
-The new conversions in Perl's sprintf() are:
+See L<perlref>.
- %i a synonym for %d
- %p a pointer (the address of the Perl value, in hexadecimal)
- %n special: B<stores> into the next variable in the parameter
- list the number of characters printed so far
+=head2 C<EXPR foreach EXPR> is supported
-The new flags that go between the C<%> and the conversion are:
+See L<perlsyn>.
- # prefix octal with "0", hex with "0x"
- h interpret integer as C type "short" or "unsigned short"
- V interpret integer as Perl's standard integer type
+=head2 Slice notation on glob elements is supported
-Also, where a number would appear in the flags, an asterisk ("*") may
-be used instead, in which case Perl uses the next item in the
-parameter list as the given number (that is, as the field width or
-precision). If a field width obtained through "*" is negative, it has
-the same effect as the '-' flag: left-justification.
+[XXX See what?]
-See L<perlfunc/sprintf> for a complete list of conversion and flags.
+=head2 Keywords can be globally overridden
-=item keys as an lvalue
+See L<perlsub>.
-As an lvalue, C<keys> allows you to increase the number of hash buckets
-allocated for the given hash. This can gain you a measure of efficiency if
-you know the hash is going to get big. (This is similar to pre-extending
-an array by assigning a larger number to $#array.) If you say
+=head2 C<$^E> is meaningful on Win32
- keys %hash = 200;
+See L<perlvar>.
-then C<%hash> will have at least 200 buckets allocated for it. These
-buckets will be retained even if you do C<%hash = ()>; use C<undef
-%hash> if you want to free the storage while C<%hash> is still in scope.
-You can't shrink the number of buckets allocated for the hash using
-C<keys> in this way (but you needn't worry about doing this by accident,
-as trying has no effect).
+=head2 C<foreach (1..1000000)> optimized
-=item my() in Control Structures
+C<foreach (1..1000000)> is now optimized into a counting loop. It does
+not try to allocate a 1000000-size list anymore.
-You can now use my() (with or without the parentheses) in the control
-expressions of control structures such as:
+=head2 C<Foo::> can be used as implicitly quoted package name
- while (defined(my $line = <>)) {
- $line = lc $line;
- } continue {
- print $line;
- }
+[XXX See what?]
- if ((my $answer = <STDIN>) =~ /^y(es)?$/i) {
- user_agrees();
- } elsif ($answer =~ /^n(o)?$/i) {
- user_disagrees();
- } else {
- chomp $answer;
- die "`$answer' is neither `yes' nor `no'";
- }
+=head2 C<exists $Foo::{Bar::}> tests existence of a package
-Also, you can declare a foreach loop control variable as lexical by
-preceding it with the word "my". For example, in:
+[XXX See what?]
- foreach my $i (1, 2, 3) {
- some_function();
- }
+=head2 Better locale support
-$i is a lexical variable, and the scope of $i extends to the end of
-the loop, but not beyond it.
+See L<perllocale>.
-Note that you still cannot use my() on global punctuation variables
-such as $_ and the like.
+=head2 Experimental support for 64-bit platforms
-=item pack() and unpack()
+Perl5 has always had 64-bit support on systems with 64-bit longs.
+Starting with 5.005, the beginnings of experimental support for systems
+with 32-bit long and 64-bit 'long long' integers has been added.
+If you add -DUSE_LONG_LONG to your ccflags in config.sh (or manually
+define it in perl.h) then perl will be built with 'long long' support.
+There will be many compiler warnings, and the resultant perl may not
+work on all systems. There are many other issues related to
+third-party extensions and libraries. This option exists to allow
+people to work on those issues.
-A new format 'w' represents a BER compressed integer (as defined in
-ASN.1). Its format is a sequence of one or more bytes, each of which
-provides seven bits of the total value, with the most significant
-first. Bit eight of each byte is set, except for the last byte, in
-which bit eight is clear.
+=head2 prototype() returns useful results on builtins
-Both pack() and unpack() now fail when their templates contain invalid
-types. (Invalid types used to be ignored.)
+See L<perlfunc/prototype>.
-=item sysseek()
+=head2 Extended support for exception handling
-The new sysseek() operator is a variant of seek() that sets and gets the
-file's system read/write position, using the lseek(2) system call. It is
-the only reliable way to seek before using sysread() or syswrite(). Its
-return value is the new position, or the undefined value on failure.
+C<die()> now accepts a reference value, and C<$@> gets set to that
+value in exception traps. This makes it possible to propagate
+exception objects. See L<perlfunc/eval>. [XXX there's nothing
+about this in perlfunc/eval yet.]
-=item use VERSION
+=head2 Re-blessing in DESTROY() supported for chaining DESTROY() methods
-If the first argument to C<use> is a number, it is treated as a version
-number instead of a module name. If the version of the Perl interpreter
-is less than VERSION, then an error message is printed and Perl exits
-immediately. Because C<use> occurs at compile time, this check happens
-immediately during the compilation process, unlike C<require VERSION>,
-which waits until runtime for the check. This is often useful if you
-need to check the current Perl version before C<use>ing library modules
-which have changed in incompatible ways from older versions of Perl.
-(We try not to do this more than we have to.)
+See L<perlobj/Destructors>.
-=item use Module VERSION LIST
+=head2 All C<printf> format conversions are handled internally
-If the VERSION argument is present between Module and LIST, then the
-C<use> will call the VERSION method in class Module with the given
-version as an argument. The default VERSION method, inherited from
-the UNIVERSAL class, croaks if the given version is larger than the
-value of the variable $Module::VERSION. (Note that there is not a
-comma after VERSION!)
+See L<perlfunc/printf>.
-This version-checking mechanism is similar to the one currently used
-in the Exporter module, but it is faster and can be used with modules
-that don't use the Exporter. It is the recommended method for new
-code.
-
-=item prototype(FUNCTION)
-
-Returns the prototype of a function as a string (or C<undef> if the
-function has no prototype). FUNCTION is a reference to or the name of the
-function whose prototype you want to retrieve.
-(Not actually new; just never documented before.)
+=head2 New C<INIT> keyword
-=item srand
-
-The default seed for C<srand>, which used to be C<time>, has been changed.
-Now it's a heady mix of difficult-to-predict system-dependent values,
-which should be sufficient for most everyday purposes.
-
-Previous to version 5.004, calling C<rand> without first calling C<srand>
-would yield the same sequence of random numbers on most or all machines.
-Now, when perl sees that you're calling C<rand> and haven't yet called
-C<srand>, it calls C<srand> with the default seed. You should still call
-C<srand> manually if your code might ever be run on a pre-5.004 system,
-of course, or if you want a seed other than the default.
-
-=item $_ as Default
-
-Functions documented in the Camel to default to $_ now in
-fact do, and all those that do are so documented in L<perlfunc>.
-
-=item C<m//g> does not reset search position on failure
-
-The C<m//g> match iteration construct used to reset its target string's
-search position (which is visible through the C<pos> operator) when a
-match failed; as a result, the next C<m//g> match would start at the
-beginning of the string). With Perl 5.004, the search position must be
-reset explicitly, as with C<pos $str = 0;>, or by modifying the target
-string. This change in Perl makes it possible to chain matches together
-in conjunction with the C<\G> zero-width assertion. See L<perlop> and
-L<perlre>.
-
-Here is an illustration of what it takes to get the old behavior:
-
- for ( qw(this and that are not what you think you got) ) {
- while ( /(\w*t\w*)/g ) { print "t word is: $1\n" }
- pos = 0; # REQUIRED FOR 5.004
- while ( /(\w*a\w*)/g ) { print "a word is: $1\n" }
- print "\n";
- }
+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.
-=item C<m//x> ignores whitespace before ?*+{}
+[XXX Needs to be documented in perlsub or perlmod.]
-The C<m//x> construct has always been intended to ignore all unescaped
-whitespace. However, before Perl 5.004, whitespace had the effect of
-escaping repeat modifiers like "*" or "?"; for example, C</a *b/x> was
-(mis)interpreted as C</a\*b/x>. This bug has been fixed in 5.004.
+=head2 New C<lock> keyword
-=item nested C<sub{}> closures work now
-
-Prior to the 5.004 release, nested anonymous functions didn't work
-right. They do now.
-
-=item formats work right on changing lexicals
-
-Just like anonymous functions that contain lexical variables
-that change (like a lexical index variable for a C<foreach> loop),
-formats now work properly. For example, this silently failed
-before, and is fine now:
+The C<lock> keyword is the fundamental synchronization primitive
+in threaded perl. When threads are not enabled, it is currently a noop.
- my $i;
- foreach $i ( 1 .. 10 ) {
- format =
- my i is @#
- $i
- .
- write;
- }
+To minimize impact on source compatibility this keyword is "weak", i.e., any
+user-defined subroutine of the same name overrides it, unless a C<use Thread>
+has been seen.
-=back
+=head2 New C<qr//> operator
-=head2 New builtin methods
+The C<qr//> operator, which is syntactically similar to the other quote-like
+operators, is used to create compiled regular expressions. This compiled
+form can now be explicitly passed around in variables, and interpolated in
+other regular expressions. See L<perlop> and L<perlre>.
-The C<UNIVERSAL> package automatically contains the following methods that
-are inherited by all other classes:
+=head2 C<our> is now a reserved word
-=over
+=head2 Tied arrays are now fully supported
-=item isa(CLASS)
+See L<Tie::Array>.
-C<isa> returns I<true> if its object is blessed into a subclass of C<CLASS>
+=head2 Tied handles support is better
-C<isa> is also exportable and can be called as a sub with two arguments. This
-allows the ability to check what a reference points to. Example:
+Several missing hooks have been added. There is also a new base class for
+TIEARRAY implementations. See L<Tie::Array>.
- use UNIVERSAL qw(isa);
- if(isa($ref, 'ARRAY')) {
- ...
- }
+=head1 Supported Platforms
-=item can(METHOD)
+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>.
-C<can> checks to see if its object has a method called C<METHOD>,
-if it does then a reference to the sub is returned; if it does not then
-I<undef> is returned.
+=head2 New Platforms
-=item VERSION( [NEED] )
+BeOS is now supported. See L<README.beos>.
-C<VERSION> returns the version number of the class (package). If the
-NEED argument is given then it will check that the current version (as
-defined by the $VERSION variable in the given package) not less than
-NEED; it will die if this is not the case. This method is normally
-called as a class method. This method is called automatically by the
-C<VERSION> form of C<use>.
+DOS is now supported under the DJGPP tools. See L<README.dos>.
- use A 1.2 qw(some imported subs);
- # implies:
- A->VERSION(1.2);
+=head2 Changes in existing support
-=back
+Win32 support has been vastly enhanced. Support for Perl Object, a C++
+encapsulation of Perl. GCC and EGCS are now supported on Win32.
+[XXX Perl Object needs a big explanation elsewhere, and a pointer to
+that location here.]
-B<NOTE:> C<can> directly uses Perl's internal code for method lookup, and
-C<isa> uses a very similar method and caching strategy. This may cause
-strange effects if the Perl code dynamically changes @ISA in any package.
+VMS configuration system has been rewritten. See L<README.vms>.
-You may add other methods to the UNIVERSAL class via Perl or XS code.
-You do not need to C<use UNIVERSAL> in order to make these methods
-available to your program. This is necessary only if you wish to
-have C<isa> available as a plain subroutine in the current package.
+OpenBSD better supported. [XXX what others?]
-=head2 TIEHANDLE now supported
+=head1 Modules and Pragmata
-See L<perltie> for other kinds of tie()s.
+=head2 New Modules
=over
-=item TIEHANDLE classname, LIST
-
-This is the constructor for the class. That means it is expected to
-return an object of some sort. The reference can be used to
-hold some internal information.
-
- sub TIEHANDLE {
- print "<shout>\n";
- my $i;
- return bless \$i, shift;
- }
+=item B
-=item PRINT this, LIST
+Perl compiler and tools. See [XXX what?].
-This method will be triggered every time the tied handle is printed to.
-Beyond its self reference it also expects the list that was passed to
-the print function.
+=item Data::Dumper
- sub PRINT {
- $r = shift;
- $$r++;
- return print join( $, => map {uc} @_), $\;
- }
+A module to pretty print Perl data. See L<Data::Dumper>.
-=item PRINTF this, LIST
+=item Errno
-This method will be triggered every time the tied handle is printed to
-with the C<printf()> function.
-Beyond its self reference it also expects the format and list that was
-passed to the printf function.
+A module to look up errors more conveniently. See L<Errno>.
- sub PRINTF {
- shift;
- my $fmt = shift;
- print sprintf($fmt, @_)."\n";
- }
+=item File::Spec
-=item READ this LIST
+A portable API for file operations.
-This method will be called when the handle is read from via the C<read>
-or C<sysread> functions.
+=item ExtUtils::Installed
- sub READ {
- $r = shift;
- my($buf,$len,$offset) = @_;
- print "READ called, \$buf=$buf, \$len=$len, \$offset=$offset";
- }
+Query and manage installed modules.
-=item READLINE this
+=item ExtUtils::Packlist
-This method will be called when the handle is read from. The method
-should return undef when there is no more data.
+Manipulate .packlist files.
- sub READLINE {
- $r = shift;
- return "PRINT called $$r times\n"
- }
+=item Fatal
-=item GETC this
+Make functions/builtins succeed or die.
-This method will be called when the C<getc> function is called.
+=item IPC::SysV
- sub GETC { print "Don't GETC, Get Perl"; return "a"; }
+Constants and other support infrastructure for System V IPC operations
+in perl.
-=item DESTROY this
+=item Test
-As with the other types of ties, this method will be called when the
-tied handle is about to be destroyed. This is useful for debugging and
-possibly for cleaning up.
+A framework for writing testsuites.
- sub DESTROY {
- print "</shout>\n";
- }
+=item Tie::Array
-=back
-
-=head2 Malloc enhancements
+Base class for tied arrays.
-Four new compilation flags are recognized by malloc.c. (They have no
-effect if perl is compiled with system malloc().)
+=item Tie::Handle
-=over
+Base class for tied handles.
-=item -DDEBUGGING_MSTATS
+=item Thread
-If perl is compiled with C<DEBUGGING_MSTATS> defined, you can print
-memory statistics at runtime by running Perl thusly:
+Perl thread creation, manipulation, and support.
- env PERL_DEBUG_MSTATS=2 perl your_script_here
+=item attrs
-The value of 2 means to print statistics after compilation and on
-exit; with a value of 1, the statistics ares printed only on exit.
-(If you want the statistics at an arbitrary time, you'll need to
-install the optional module Devel::Peek.)
+Set subroutine attributes.
-=item -DEMERGENCY_SBRK
+=item fields
-If this macro is defined, running out of memory need not be a fatal
-error: a memory pool can allocated by assigning to the special
-variable C<$^M>. See L<"$^M">.
+Compile-time class fields.
-=item -DPACK_MALLOC
+=item re
-Perl memory allocation is by bucket with sizes close to powers of two.
-Because of these malloc overhead may be big, especially for data of
-size exactly a power of two. If C<PACK_MALLOC> is defined, perl uses
-a slightly different algorithm for small allocations (up to 64 bytes
-long), which makes it possible to have overhead down to 1 byte for
-allocations which are powers of two (and appear quite often).
-
-Expected memory savings (with 8-byte alignment in C<alignbytes>) is
-about 20% for typical Perl usage. Expected slowdown due to additional
-malloc overhead is in fractions of a percent (hard to measure, because
-of the effect of saved memory on speed).
-
-=item -DTWO_POT_OPTIMIZE
-
-Similarly to C<PACK_MALLOC>, this macro improves allocations of data
-with size close to a power of two; but this works for big allocations
-(starting with 16K by default). Such allocations are typical for big
-hashes and special-purpose scripts, especially image processing.
-
-On recent systems, the fact that perl requires 2M from system for 1M
-allocation will not affect speed of execution, since the tail of such
-a chunk is not going to be touched (and thus will not require real
-memory). However, it may result in a premature out-of-memory error.
-So if you will be manipulating very large blocks with sizes close to
-powers of two, it would be wise to define this macro.
-
-Expected saving of memory is 0-100% (100% in applications which
-require most memory in such 2**n chunks); expected slowdown is
-negligible.
+Various pragmata to control behavior of regular expressions.
=back
-=head2 Miscellaneous efficiency enhancements
-
-Functions that have an empty prototype and that do nothing but return
-a fixed value are now inlined (e.g. C<sub PI () { 3.14159 }>).
-
-Each unique hash key is only allocated once, no matter how many hashes
-have an entry with that key. So even if you have 100 copies of the
-same hash, the hash keys never have to be reallocated.
-
-=head1 Pragmata
-
-Six new pragmatic modules exist:
+=head2 Changes in existing modules
=over
-=item use autouse MODULE => qw(sub1 sub2 sub3)
-
-Defers C<require MODULE> until someone calls one of the specified
-subroutines (which must be exported by MODULE). This pragma should be
-used with caution, and only when necessary.
-
-=item use blib
-
-=item use blib 'dir'
-
-Looks for MakeMaker-like I<'blib'> directory structure starting in
-I<dir> (or current directory) and working back up to five levels of
-parent directories.
-
-Intended for use on command line with B<-M> option as a way of testing
-arbitrary scripts against an uninstalled version of a package.
-
-=item use constant NAME => VALUE
-
-Provides a convenient interface for creating compile-time constants,
-See L<perlsub/"Constant Functions">.
-
-=item use locale
-
-Tells the compiler to enable (or disable) the use of POSIX locales for
-builtin operations.
-
-When C<use locale> is in effect, the current LC_CTYPE locale is used
-for regular expressions and case mapping; LC_COLLATE for string
-ordering; and LC_NUMERIC for numeric formating in printf and sprintf
-(but B<not> in print). LC_NUMERIC is always used in write, since
-lexical scoping of formats is problematic at best.
-
-Each C<use locale> or C<no locale> affects statements to the end of
-the enclosing BLOCK or, if not inside a BLOCK, to the end of the
-current file. Locales can be switched and queried with
-POSIX::setlocale().
-
-See L<perllocale> for more information.
-
-=item use ops
-
-Disable unsafe opcodes, or any named opcodes, when compiling Perl code.
-
-=item use vmsish
-
-Enable VMS-specific language features. Currently, there are three
-VMS-specific features available: 'status', which makes C<$?> and
-C<system> return genuine VMS status values instead of emulating POSIX;
-'exit', which makes C<exit> take a genuine VMS status value instead of
-assuming that C<exit 1> is an error; and 'time', which makes all times
-relative to the local time zone, in the VMS tradition.
-
-=back
-
-=head1 Modules
-
-=head2 Required Updates
-
-Though Perl 5.004 is compatible with almost all modules that work
-with Perl 5.003, there are a few exceptions:
-
- Module Required Version for Perl 5.004
- ------ -------------------------------
- Filter Filter-1.12
- LWP libwww-perl-5.08
- Tk Tk400.202 (-w makes noise)
-
-Also, the majordomo mailing list program, version 1.94.1, doesn't work
-with Perl 5.004 (nor with perl 4), because it executes an invalid
-regular expression. This bug is fixed in majordomo version 1.94.2.
-
-=head2 Installation directories
-
-The I<installperl> script now places the Perl source files for
-extensions in the architecture-specific library directory, which is
-where the shared libraries for extensions have always been. This
-change is intended to allow administrators to keep the Perl 5.004
-library directory unchanged from a previous version, without running
-the risk of binary incompatibility between extensions' Perl source and
-shared libraries.
-
-=head2 Module information summary
-
-Brand new modules, arranged by topic rather than strictly
-alphabetically:
-
- CGI.pm Web server interface ("Common Gateway Interface")
- CGI/Apache.pm Support for Apache's Perl module
- CGI/Carp.pm Log server errors with helpful context
- CGI/Fast.pm Support for FastCGI (persistent server process)
- CGI/Push.pm Support for server push
- CGI/Switch.pm Simple interface for multiple server types
-
- CPAN Interface to Comprehensive Perl Archive Network
- CPAN::FirstTime Utility for creating CPAN configuration file
- CPAN::Nox Runs CPAN while avoiding compiled extensions
-
- IO.pm Top-level interface to IO::* classes
- IO/File.pm IO::File extension Perl module
- IO/Handle.pm IO::Handle extension Perl module
- IO/Pipe.pm IO::Pipe extension Perl module
- IO/Seekable.pm IO::Seekable extension Perl module
- IO/Select.pm IO::Select extension Perl module
- IO/Socket.pm IO::Socket extension Perl module
-
- Opcode.pm Disable named opcodes when compiling Perl code
-
- ExtUtils/Embed.pm Utilities for embedding Perl in C programs
- ExtUtils/testlib.pm Fixes up @INC to use just-built extension
-
- FindBin.pm Find path of currently executing program
-
- Class/Struct.pm Declare struct-like datatypes as Perl classes
- File/stat.pm By-name interface to Perl's builtin stat
- Net/hostent.pm By-name interface to Perl's builtin gethost*
- Net/netent.pm By-name interface to Perl's builtin getnet*
- Net/protoent.pm By-name interface to Perl's builtin getproto*
- Net/servent.pm By-name interface to Perl's builtin getserv*
- Time/gmtime.pm By-name interface to Perl's builtin gmtime
- Time/localtime.pm By-name interface to Perl's builtin localtime
- Time/tm.pm Internal object for Time::{gm,local}time
- User/grent.pm By-name interface to Perl's builtin getgr*
- User/pwent.pm By-name interface to Perl's builtin getpw*
-
- Tie/RefHash.pm Base class for tied hashes with references as keys
-
- UNIVERSAL.pm Base class for *ALL* classes
-
-=head2 Fcntl
-
-New constants in the existing Fcntl modules are now supported,
-provided that your operating system happens to support them:
-
- F_GETOWN F_SETOWN
- O_ASYNC O_DEFER O_DSYNC O_FSYNC O_SYNC
- O_EXLOCK O_SHLOCK
-
-These constants are intended for use with the Perl operators sysopen()
-and fcntl() and the basic database modules like SDBM_File. For the
-exact meaning of these and other Fcntl constants please refer to your
-operating system's documentation for fcntl() and open().
-
-In addition, the Fcntl module now provides these constants for use
-with the Perl operator flock():
-
- LOCK_SH LOCK_EX LOCK_NB LOCK_UN
-
-These constants are defined in all environments (because where there is
-no flock() system call, Perl emulates it). However, for historical
-reasons, these constants are not exported unless they are explicitly
-requested with the ":flock" tag (e.g. C<use Fcntl ':flock'>).
-
-=head2 IO
-
-The IO module provides a simple mechanism to load all of the IO modules at one
-go. Currently this includes:
-
- IO::Handle
- IO::Seekable
- IO::File
- IO::Pipe
- IO::Socket
-
-For more information on any of these modules, please see its
-respective documentation.
-
-=head2 Math::Complex
-
-The Math::Complex module has been totally rewritten, and now supports
-more operations. These are overloaded:
-
- + - * / ** <=> neg ~ abs sqrt exp log sin cos atan2 "" (stringify)
-
-And these functions are now exported:
-
- pi i Re Im arg
- log10 logn ln cbrt root
- tan
- csc sec cot
- asin acos atan
- acsc asec acot
- sinh cosh tanh
- csch sech coth
- asinh acosh atanh
- acsch asech acoth
- cplx cplxe
+=item CGI
-=head2 Math::Trig
+CGI has been updated to version 2.42.
-This new module provides a simpler interface to parts of Math::Complex for
-those who need trigonometric functions only for real numbers.
+=item POSIX
-=head2 DB_File
+POSIX now has its own platform-specific hints files.
-There have been quite a few changes made to DB_File. Here are a few of
-the highlights:
+=item DB_File
-=over
-
-=item *
-
-Fixed a handful of bugs.
-
-=item *
+DB_File supports version 2.x of Berkeley DB. See C<ext/DB_File/Changes>.
-By public demand, added support for the standard hash function exists().
+=item MakeMaker
-=item *
+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.
-Made it compatible with Berkeley DB 1.86.
+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 *
+=item CPAN
-Made negative subscripts work with RECNO interface.
+[XXX What?]
-=item *
+=item Cwd
-Changed the default flags from O_RDWR to O_CREAT|O_RDWR and the default
-mode from 0640 to 0666.
+Cwd::cwd is faster on most platforms.
-=item *
+=item Benchmark
-Made DB_File automatically import the open() constants (O_RDWR,
-O_CREAT etc.) from Fcntl, if available.
-
-=item *
-
-Updated documentation.
+Keeps better time.
=back
-Refer to the HISTORY section in DB_File.pm for a complete list of
-changes. Everything after DB_File 1.01 has been added since 5.003.
-
-=head2 Net::Ping
-
-Major rewrite - support added for both udp echo and real icmp pings.
-
-=head2 Object-oriented overrides for builtin operators
-
-Many of the Perl builtins returning lists now have
-object-oriented overrides. These are:
-
- File::stat
- Net::hostent
- Net::netent
- Net::protoent
- Net::servent
- Time::gmtime
- Time::localtime
- User::grent
- User::pwent
-
-For example, you can now say
-
- use File::stat;
- use User::pwent;
- $his = (stat($filename)->st_uid == pwent($whoever)->pw_uid);
-
=head1 Utility Changes
-=head2 xsubpp
-
-=over
-
-=item C<void> XSUBs now default to returning nothing
-
-Due to a documentation/implementation bug in previous versions of
-Perl, XSUBs with a return type of C<void> have actually been
-returning one value. Usually that value was the GV for the XSUB,
-but sometimes it was some already freed or reused value, which would
-sometimes lead to program failure.
-
-In Perl 5.004, if an XSUB is declared as returning C<void>, it
-actually returns no value, i.e. an empty list (though there is a
-backward-compatibility exception; see below). If your XSUB really
-does return an SV, you should give it a return type of C<SV *>.
-
-For backward compatibility, I<xsubpp> tries to guess whether a
-C<void> XSUB is really C<void> or if it wants to return an C<SV *>.
-It does so by examining the text of the XSUB: if I<xsubpp> finds
-what looks like an assignment to C<ST(0)>, it assumes that the
-XSUB's return type is really C<SV *>.
-
-=back
-
-=head1 C Language API Changes
-
-=over
-
-=item C<gv_fetchmethod> and C<perl_call_sv>
-
-The C<gv_fetchmethod> function finds a method for an object, just like
-in Perl 5.003. The GV it returns may be a method cache entry.
-However, in Perl 5.004, method cache entries are not visible to users;
-therefore, they can no longer be passed directly to C<perl_call_sv>.
-Instead, you should use the C<GvCV> macro on the GV to extract its CV,
-and pass the CV to C<perl_call_sv>.
+h2ph and related utilities have been vastly overhauled.
-The most likely symptom of passing the result of C<gv_fetchmethod> to
-C<perl_call_sv> is Perl's producing an "Undefined subroutine called"
-error on the I<second> call to a given method (since there is no cache
-on the first call).
+perlcc, a new experimental front end for the compiler is available.
-=item C<perl_eval_pv>
+The crude GNU configure emulator is now called configure.gnu.
-A new function handy for eval'ing strings of Perl code inside C code.
-This function returns the value from the eval statement, which can
-be used instead of fetching globals from the symbol table. See
-L<perlguts>, L<perlembed> and L<perlcall> for details and examples.
+=head1 API Changes
-=item Extended API for manipulating hashes
+=head2 Incompatible Changes
-Internal handling of hash keys has changed. The old hashtable API is
-still fully supported, and will likely remain so. The additions to the
-API allow passing keys as C<SV*>s, so that C<tied> hashes can be given
-real scalars as keys rather than plain strings (nontied hashes still
-can only use strings as keys). New extensions must use the new hash
-access functions and macros if they wish to use C<SV*> keys. These
-additions also make it feasible to manipulate C<HE*>s (hash entries),
-which can be more efficient. See L<perlguts> for details.
+=head2 Deprecations, Extensions
-=back
+=head2 C++ Support
=head1 Documentation Changes
-Many of the base and library pods were updated. These
-new pods are included in section 1:
-
-=over
-
-=item L<perldelta>
-
-This document.
-
-=item L<perllocale>
-
-Locale support (internationalization and localization).
-
-=item L<perltoot>
-
-Tutorial on Perl OO programming.
-
-=item L<perlapio>
-
-Perl internal IO abstraction interface.
+Config.pm now has a glossary of variables.
-=item L<perldebug>
-
-Although not new, this has been massively updated.
-
-=item L<perlsec>
-
-Although not new, this has been massively updated.
-
-=back
+Porting/patching.pod has detailed instructions on how to create and
+submit patches for perl.
=head1 New Diagnostics
-Several new conditions will trigger warnings that were
-silent before. Some only affect certain platforms.
-The following new warnings and errors outline these.
-These messages are classified as follows (listed in
-increasing order of desperation):
-
- (W) A warning (optional).
- (D) A deprecation (optional).
- (S) A severe warning (mandatory).
- (F) A fatal error (trappable).
- (P) An internal error you should never see (trappable).
- (X) A very fatal error (nontrappable).
- (A) An alien error message (not generated by Perl).
-
=over
-=item "my" variable %s masks earlier declaration in same scope
-
-(S) A lexical variable has been redeclared in the same scope, effectively
-eliminating all access to the previous instance. This is almost always
-a typographical error. Note that the earlier variable will still exist
-until the end of the scope or until all closure referents to it are
-destroyed.
-
-=item %s argument is not a HASH element or slice
-
-(F) The argument to delete() must be either a hash element, such as
-
- $foo{$bar}
- $ref->[12]->{"susie"}
-
-or a hash slice, such as
+=item Ambiguous call resolved as CORE::%s(), qualify as such or use &
- @foo{$bar, $baz, $xyzzy}
- @{$ref->[12]}{"susie", "queue"}
+(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.
-=item Allocation too large: %lx
+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).
-(X) You can't allocate more than 64K on an MS-DOS machine.
+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 Allocation too large
+=item Bad index while coercing array into hash
-(F) You can't allocate more than 2^31+"small amount" bytes.
+(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 Applying %s to %s will act on scalar(%s)
+=item Bareword "%s" refers to nonexistent package
-(W) The pattern match (//), substitution (s///), and translation (tr///)
-operators work on scalar values. If you apply one of them to an array
-or a hash, it will convert the array or hash to a scalar value -- the
-length of an array, or the population info of a hash -- and then work on
-that scalar value. This is probably not what you meant to do. See
-L<perlfunc/grep> and L<perlfunc/map> for alternatives.
+(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 Attempt to free nonexistent shared string
+=item Can't call method "%s" on an undefined value
-(P) Perl maintains a reference counted internal table of strings to
-optimize the storage and access of hash keys and other strings. This
-indicates someone tried to decrement the reference count of a string
-that can no longer be found in the table.
+(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:
-=item Attempt to use reference as lvalue in substr
+ $BADREF = 42;
+ process $BADREF 1,2,3;
+ $BADREF->process(1,2,3);
-(W) You supplied a reference as the first argument to substr() used
-as an lvalue, which is pretty strange. Perhaps you forgot to
-dereference it first. See L<perlfunc/substr>.
+=item Can't coerce array into hash
-=item Can't use bareword ("%s") as %s ref while "strict refs" in use
+(F) You used an array where a hash was expected, but the array has no
+information on how to map from keys to array indices. You can do that
+only with arrays that have a hash reference at index 0.
-(F) Only hard references are allowed by "strict refs". Symbolic references
-are disallowed. See L<perlref>.
+=item Can't goto subroutine from an eval-string
-=item Cannot resolve method `%s' overloading `%s' in package `%s'
+(F) The "goto subroutine" call can't be used to jump out of an eval "string".
+(You can use it to jump out of an eval {BLOCK}, but you probably don't want to.)
-(P) Internal error trying to resolve overloading specified by a method
-name (as opposed to a subroutine reference).
+=item Can't use %%! because Errno.pm is not available
-=item Constant subroutine %s redefined
+(F) The first time the %! hash is used, perl automatically loads the
+Errno.pm module. The Errno module is expected to tie the %! hash to
+provide symbolic names for C<$!> errno values.
-(S) You redefined a subroutine which had previously been eligible for
-inlining. See L<perlsub/"Constant Functions"> for commentary and
-workarounds.
+=item Can't use %%! because Errno.pm is not available
-=item Constant subroutine %s undefined
+(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.
-(S) You undefined a subroutine which had previously been eligible for
-inlining. See L<perlsub/"Constant Functions"> for commentary and
-workarounds.
+=item Cannot find an opnumber for "%s"
-=item Copy method did not return a reference
+(F) A string of a form C<CORE::word> was given to prototype(), but
+there is no builtin with the name C<word>.
-(F) The method which overloads "=" is buggy. See L<overload/Copy Constructor>.
+=item Character class syntax [. .] is reserved for future extensions
-=item Died
+(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: "\[." and ".\]".
-(F) You passed die() an empty string (the equivalent of C<die "">) or
-you called it with no args and both C<$@> and C<$_> were empty.
+=item Character class syntax [: :] is reserved for future extensions
-=item Exiting pseudo-block via %s
+(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: "\[:" and ":\]".
-(W) You are exiting a rather special block construct (like a sort block or
-subroutine) by unconventional means, such as a goto, or a loop control
-statement. See L<perlfunc/sort>.
+=item Character class syntax [= =] is reserved for future extensions
-=item Identifier too long
+(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: "\[=" and "=\]".
-(F) Perl limits identifiers (names for variables, functions, etc.) to
-252 characters for simple names, somewhat more for compound names (like
-C<$A::B>). You've exceeded Perl's limits. Future versions of Perl are
-likely to eliminate these arbitrary limitations.
+=item %s: Eval-group in insecure regular expression
-=item Illegal character %s (carriage return)
+(F) Perl detected tainted data when trying to compile a regular expression
+that contains the C<(?{ ... })> zero-width assertion, which is unsafe.
+See L<perlre/(?{ code })>, and L<perlsec>.
-(F) A carriage return character was found in the input. This is an
-error, and not a warning, because carriage return characters can break
-multi-line strings, including here documents (e.g., C<print E<lt>E<lt>EOF;>).
+=item %s: Eval-group not allowed, use re 'eval'
-=item Illegal switch in PERL5OPT: %s
+(F) A regular expression contained the C<(?{ ... })> zero-width assertion,
+but that construct is only allowed when the C<use re 'eval'> pragma is
+in effect. See L<perlre/(?{ code })>.
-(X) The PERL5OPT environment variable may only be used to set the
-following switches: B<-[DIMUdmw]>.
+=item %s: Eval-group not allowed at run time
-=item Integer overflow in hex number
+(F) Perl tried to compile a regular expression containing the C<(?{ ... })>
+zero-width assertion at run time, as it would when the pattern contains
+interpolated values. Since that is a security risk, it is not allowed.
+If you insist, you may still do this by explicitly building the pattern
+from an interpolated string at run time and using that in an eval().
+See L<perlre/(?{ code })>.
-(S) The literal hex number you have specified is too big for your
-architecture. On a 32-bit architecture the largest hex literal is
-0xFFFFFFFF.
+=item Explicit blessing to '' (assuming package main)
-=item Integer overflow in octal number
+(W) You are blessing a reference to a zero length string. This has
+the effect of blessing the reference into the package main. This is
+usually not what you want. Consider providing a default target
+package, e.g. bless($ref, $p or 'MyPackage');
-(S) The literal octal number you have specified is too big for your
-architecture. On a 32-bit architecture the largest octal literal is
-037777777777.
+=item Illegal hex digit ignored
-=item internal error: glob failed
+(W) You may have tried to use a character other than 0 - 9 or A - F in a
+hexadecimal number. Interpretation of the hexadecimal number stopped
+before the illegal character.
-(P) Something went wrong with the external program(s) used for C<glob>
-and C<E<lt>*.cE<gt>>. This may mean that your csh (C shell) is
-broken. If so, you should change all of the csh-related variables in
-config.sh: If you have tcsh, make the variables refer to it as if it
-were csh (e.g. C<full_csh='/usr/bin/tcsh'>); otherwise, make them all
-empty (except that C<d_csh> should be C<'undef'>) so that Perl will
-think csh is missing. In either case, after editing config.sh, run
-C<./Configure -S> and rebuild Perl.
+=item No such array field
-=item Invalid conversion in %s: "%s"
+(F) You tried to access an array as a hash, but the field name used is
+not defined. The hash at index 0 should map all valid field names to
+array indices for that to work.
-(W) Perl does not understand the given format conversion.
-See L<perlfunc/sprintf>.
+=item No such field "%s" in variable %s of type %s
-=item Invalid type in pack: '%s'
+(F) You tried to access a field of a typed variable where the type
+does not know about the field name. The field names are looked up in
+the %FIELDS hash in the type package at compile time. The %FIELDS hash
+is usually set up with the 'fields' pragma.
-(F) The given character is not a valid pack type. See L<perlfunc/pack>.
+=item Out of memory during ridiculously large request
-=item Invalid type in unpack: '%s'
+(F) You can't allocate more than 2^31+"small amount" bytes. This error
+is most likely to be caused by a typo in the Perl program. e.g., C<$arr[time]>
+instead of C<$arr[$time]>.
-(F) The given character is not a valid unpack type. See L<perlfunc/unpack>.
+=item Range iterator outside integer range
-=item Name "%s::%s" used only once: possible typo
+(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.
-(W) Typographical errors often show up as unique variable names.
-If you had a good reason for having a unique name, then just mention
-it again somehow to suppress the message (the C<use vars> pragma is
-provided for just this purpose).
+=item Recursive inheritance detected while looking for method '%s' in package '%s'
-=item Null picture in formline
+(F) More than 100 levels of inheritance were encountered while invoking a
+method. Probably indicates an unintended loop in your inheritance hierarchy.
-(F) The first argument to formline must be a valid format picture
-specification. It was found to be empty, which probably means you
-supplied it an uninitialized value. See L<perlform>.
+=item Reference found where even-sized list expected
-=item Offset outside string
+(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>.
-(F) You tried to do a read/write/send/recv operation with an offset
-pointing outside the buffer. This is difficult to imagine.
-The sole exception to this is that C<sysread()>ing past the buffer
-will extend the buffer and zero pad the new area.
+ %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 Out of memory!
+=item Undefined value assigned to typeglob
-(X|F) The malloc() function returned 0, indicating there was insufficient
-remaining memory (or virtual memory) to satisfy the request.
+(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>.
-The request was judged to be small, so the possibility to trap it
-depends on the way Perl was compiled. By default it is not trappable.
-However, if compiled for this, Perl may use the contents of C<$^M> as
-an emergency pool after die()ing with this message. In this case the
-error is trappable I<once>.
+=item Use of reserved word "%s" is deprecated
-=item Out of memory during request for %s
+(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()>.
-(F) The malloc() function returned 0, indicating there was insufficient
-remaining memory (or virtual memory) to satisfy the request. However,
-the request was judged large enough (compile-time default is 64K), so
-a possibility to shut down by trapping this error is granted.
+=item perl: warning: Setting locale failed.
-=item panic: frexp
+(S) The whole warning message will look something like:
-(P) The library function frexp() failed, making printf("%f") impossible.
+ 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").
-=item Possible attempt to put comments in qw() list
+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> section B<LOCALE PROBLEMS>.
-(W) qw() lists contain items separated by whitespace; as with literal
-strings, comment characters are not ignored, but are instead treated
-as literal data. (You may have used different delimiters than the
-exclamation marks parentheses shown here; braces are also frequently
-used.)
-
-You probably wrote something like this:
-
- @list = qw(
- a # a comment
- b # another comment
- );
-
-when you should have written this:
-
- @list = qw(
- a
- b
- );
-
-If you really want comments, build your list the
-old-fashioned way, with quotes and commas:
-
- @list = (
- 'a', # a comment
- 'b', # another comment
- );
-
-=item Possible attempt to separate words with commas
-
-(W) qw() lists contain items separated by whitespace; therefore commas
-aren't needed to separate the items. (You may have used different
-delimiters than the parentheses shown here; braces are also frequently
-used.)
-
-You probably wrote something like this:
-
- qw! a, b, c !;
-
-which puts literal commas into some of the list items. Write it without
-commas if you don't want them to appear in your data:
-
- qw! a b c !;
-
-=item Scalar value @%s{%s} better written as $%s{%s}
-
-(W) You've used a hash slice (indicated by @) to select a single element of
-a hash. Generally it's better to ask for a scalar value (indicated by $).
-The difference is that C<$foo{&bar}> always behaves like a scalar, both when
-assigning to it and when evaluating its argument, while C<@foo{&bar}> behaves
-like a list when you assign to it, and provides a list context to its
-subscript, which can do weird things if you're expecting only one subscript.
-
-=item Stub found while resolving method `%s' overloading `%s' in package `%s'
-
-(P) Overloading resolution over @ISA tree may be broken by importing stubs.
-Stubs should never be implicitely created, but explicit calls to C<can>
-may break this.
-
-=item Too late for "B<-T>" option
-
-(X) The #! line (or local equivalent) in a Perl script contains the
-B<-T> option, but Perl was not invoked with B<-T> in its argument
-list. This is an error because, by the time Perl discovers a B<-T> in
-a script, it's too late to properly taint everything from the
-environment. So Perl gives up.
-
-=item untie attempted while %d inner references still exist
-
-(W) A copy of the object returned from C<tie> (or C<tied>) was still
-valid when C<untie> was called.
-
-=item Unrecognized character %s
-
-(F) The Perl parser has no idea what to do with the specified character
-in your Perl script (or eval). Perhaps you tried to run a compressed
-script, a binary program, or a directory as a Perl program.
-
-=item Unsupported function fork
-
-(F) Your version of executable does not support forking.
-
-Note that under some systems, like OS/2, there may be different flavors of
-Perl executables, some of which may support fork, some not. Try changing
-the name you call Perl by to C<perl_>, C<perl__>, and so on.
-
-=item Use of "$$<digit>" to mean "${$}<digit>" is deprecated
-
-(D) Perl versions before 5.004 misinterpreted any type marker followed
-by "$" and a digit. For example, "$$0" was incorrectly taken to mean
-"${$}0" instead of "${$0}". This bug is (mostly) fixed in Perl 5.004.
-
-However, the developers of Perl 5.004 could not fix this bug completely,
-because at least two widely-used modules depend on the old meaning of
-"$$0" in a string. So Perl 5.004 still interprets "$$<digit>" in the
-old (broken) way inside strings; but it generates this message as a
-warning. And in Perl 5.005, this special treatment will cease.
-
-=item Value of %s can be "0"; test with defined()
-
-(W) In a conditional expression, you used <HANDLE>, <*> (glob), C<each()>,
-or C<readdir()> as a boolean value. Each of these constructs can return a
-value of "0"; that would make the conditional expression false, which is
-probably not what you intended. When using these constructs in conditional
-expressions, test their values with the C<defined> operator.
-
-=item Variable "%s" may be unavailable
-
-(W) An inner (nested) I<anonymous> subroutine is inside a I<named>
-subroutine, and outside that is another subroutine; and the anonymous
-(innermost) subroutine is referencing a lexical variable defined in
-the outermost subroutine. For example:
-
- sub outermost { my $a; sub middle { sub { $a } } }
-
-If the anonymous subroutine is called or referenced (directly or
-indirectly) from the outermost subroutine, it will share the variable
-as you would expect. But if the anonymous subroutine is called or
-referenced when the outermost subroutine is not active, it will see
-the value of the shared variable as it was before and during the
-*first* call to the outermost subroutine, which is probably not what
-you want.
-
-In these circumstances, it is usually best to make the middle
-subroutine anonymous, using the C<sub {}> syntax. Perl has specific
-support for shared variables in nested anonymous subroutines; a named
-subroutine in between interferes with this feature.
-
-=item Variable "%s" will not stay shared
-
-(W) An inner (nested) I<named> subroutine is referencing a lexical
-variable defined in an outer subroutine.
-
-When the inner subroutine is called, it will probably see the value of
-the outer subroutine's variable as it was before and during the
-*first* call to the outer subroutine; in this case, after the first
-call to the outer subroutine is complete, the inner and outer
-subroutines will no longer share a common value for the variable. In
-other words, the variable will no longer be shared.
-
-Furthermore, if the outer subroutine is anonymous and references a
-lexical variable outside itself, then the outer and inner subroutines
-will I<never> share the given variable.
-
-This problem can usually be solved by making the inner subroutine
-anonymous, using the C<sub {}> syntax. When inner anonymous subs that
-reference variables in outer subroutines are called or referenced,
-they are automatically rebound to the current values of such
-variables.
-
-=item Warning: something's wrong
-
-(W) You passed warn() an empty string (the equivalent of C<warn "">) or
-you called it with no args and C<$_> was empty.
-
-=item Ill-formed logical name |%s| in prime_env_iter
-
-(W) A warning peculiar to VMS. A logical name was encountered when preparing
-to iterate over %ENV which violates the syntactic rules governing logical
-names. Since it cannot be translated normally, it is skipped, and will not
-appear in %ENV. This may be a benign occurrence, as some software packages
-might directly modify logical name tables and introduce nonstandard names,
-or it may indicate that a logical name table has been corrupted.
-
-=item Got an error from DosAllocMem
-
-(P) An error peculiar to OS/2. Most probably you're using an obsolete
-version of Perl, and this should not happen anyway.
+=back
-=item Malformed PERLLIB_PREFIX
-(F) An error peculiar to OS/2. PERLLIB_PREFIX should be of the form
+=head1 Obsolete Diagnostics
- prefix1;prefix2
+=over
-or
+=item Can't mktemp()
- prefix1 prefix2
+(F) The mktemp() routine failed for some reason while trying to process
+a B<-e> switch. Maybe your /tmp partition is full, or clobbered.
-with nonempty prefix1 and prefix2. If C<prefix1> is indeed a prefix
-of a builtin library search path, prefix2 is substituted. The error
-may appear if components are not found, or are too long. See
-"PERLLIB_PREFIX" in F<README.os2>.
+=item Can't write to temp file for B<-e>: %s
-=item PERL_SH_DIR too long
+(F) The write routine failed for some reason while trying to process
+a B<-e> switch. Maybe your /tmp partition is full, or clobbered.
-(F) An error peculiar to OS/2. PERL_SH_DIR is the directory to find the
-C<sh>-shell in. See "PERL_SH_DIR" in F<README.os2>.
+=item Cannot open temporary file
-=item Process terminated by SIG%s
+(F) The create routine failed for some reason while trying to process
+a B<-e> switch. Maybe your /tmp partition is full, or clobbered.
-(W) This is a standard message issued by OS/2 applications, while *nix
-applications die in silence. It is considered a feature of the OS/2
-port. One can easily disable this by appropriate sighandlers, see
-L<perlipc/"Signals">. See also "Process terminated by SIGTERM/SIGINT"
-in F<README.os2>.
=back
The F<Changes> file for exhaustive details on what changed.
-The F<INSTALL> file for how to build Perl. This file has been
-significantly updated for 5.004, so even veteran users should
-look through it.
+The F<INSTALL> file for how to build Perl.
The F<README> file for general stuff.
-The F<Copying> file for copyright information.
+The F<Artistic> and F<Copying> files for copyright information.
=head1 HISTORY
-Constructed by Tom Christiansen, grabbing material with permission
-from innumerable contributors, with kibitzing by more than a few Perl
-porters.
-
-Last update: Sat Mar 8 19:51:26 EST 1997
+=cut
projects / p5sagit/p5-mst-13.2.git / blobdiff