=head1 NAME
-perldelta - what's new for perl v5.6 (as of v5.005_62)
+perldelta - what's new for perl v5.6.0
=head1 DESCRIPTION
-This is an unsupported alpha release, meant for intrepid Perl developers
-only. The included sources may not even build correctly on some platforms.
-Subscribing to perl5-porters is the best way to monitor and contribute
-to the progress of development releases (see www.perl.org for info).
-
This document describes differences between the 5.005 release and this one.
=head1 Incompatible Changes
=head2 Perl Source Incompatibilities
-Beware that any new warnings that have been added or enhanced old
-warnings are B<not> considered incompatible changes.
+Beware that any new warnings that have been added or old ones
+that have been enhanced are B<not> considered incompatible changes.
Since all new warnings must be explicitly requested via the C<-w>
switch or the C<warnings> pragma, it is ultimately the programmer's
=over 4
+=item CHECK is a new keyword
+
+In addition to C<BEGIN>, C<INIT>, C<END>, C<DESTROY> and C<AUTOLOAD>,
+subroutines named C<CHECK> are now special. These are queued up during
+compilation and behave similar to END blocks, except they are called at
+the end of compilation rather than at the end of execution. They cannot
+be called directly.
+
=item Treatment of list slices of undef has changed
When taking a slice of a literal list (as opposed to a slice of
See L<perldata>.
+=head2 Perl's version numbering has changed
+
+Beginning with Perl version 5.6.0, the version number convention has been
+changed to a "dotted integer" scheme that is more commonly found in open
+source projects.
+
+Maintenance versions of v5.6.0 will be released as v5.6.1, v5.6.2 etc.
+The next development series following v5.6.0 will be numbered v5.7.x,
+beginning with v5.7.0, and the next major production release following
+v5.6.0 will be v5.8.0.
+
+The English module now sets $PERL_VERSION to $^V (a string value) rather
+than C<$]> (a numeric value). (This is a potential incompatibility.
+Send us a report via perlbug if you are affected by this.)
+
+The v1.2.3 syntax is also now legal in Perl.
+See L<Support for strings represented as a vector of ordinals> for more on that.
+
+To cope with the new versioning system's use of at least three significant
+digits for each version component, the method used for incrementing the
+subversion number has also changed slightly. We assume that versions older
+than v5.6.0 have been incrementing the subversion component in multiples of
+10. Versions after v5.6.0 will increment them by 1. Thus, using the new
+notation, 5.005_03 is the "same" as v5.5.30, and the first maintenance
+version following v5.6.0 will be v5.6.1 (which should be read as being
+equivalent to a floating point value of 5.006_001 in the older format,
+stored in C<$]>).
+
+=item Literals of the form C<1.2.3> parse differently
+
+Previously, numeric literals with more than one dot in them were
+interpreted as a floating point number concatenated with one or more
+numbers. Such "numbers" are now parsed as strings composed of the
+specified ordinals.
+
+For example, C<print 97.98.99> used to output C<97.9899> in earlier
+versions, but now prints C<abc>.
+
+See L<Support for strings represented as a vector of ordinals> below.
+
=item Possibly changed pseudo-random number generator
In 5.005_0x and earlier, perl's rand() function used the C library
the same effect as assigning C<undef> to the readonly value--it
throws an exception.
-=item Close-on-exec bit may be set on pipe() handles
+=item Close-on-exec bit may be set on pipe and socket handles
On systems that support a close-on-exec flag on filehandles, the
-flag will be set for any handles created by pipe(), if that is
-warranted by the value of $^F that may be in effect. Earlier
-versions neglected to set the flag for handles created with
-pipe(). See L<perlfunc/pipe> and L<perlvar/$^F>.
+flag will be set for any handles created by pipe(), socketpair(),
+socket(), and accept(), if that is warranted by the value of $^F
+that may be in effect. Earlier versions neglected to set the flag
+for handles created with these operators. See L<perlfunc/pipe>,
+L<perlfunc/socketpair>, L<perlfunc/socket>, L<perlfunc/accept>,
+and L<perlvar/$^F>.
=item Writing C<"$$1"> to mean C<"${$}1"> is unsupported
similar within interpolated strings to mean C<$$ . "1">,
but still allowed it.
-In Perl 5.6 and later, C<"$$1"> always means C<"${$1}">.
+In Perl 5.6.0 and later, C<"$$1"> always means C<"${$1}">.
-=item values(%h) and C<\(%h)> operate on aliases to values, not copies
+=item delete(), values() and C<\(%h)> operate on aliases to values, not copies
-each(), values() and hashes in a list context return the actual
+delete(), each(), values() and hashes in a list context return the actual
values in the hash, instead of copies (as they used to in earlier
versions). Typical idioms for using these constructs copy the
returned values, but this can make a significant difference when
has been removed, because it could potentially result in memory
leaks.
+=item Parenthesized not() behaves like a list operator
+
+The C<not> operator now falls under the "if it looks like a function,
+it behaves like a function" rule.
+
+As a result, the parenthesized form can be used with C<grep> and C<map>.
+The following construct used to be a syntax error before, but it works
+as expected now:
+
+ grep not($_), @things;
+
+On the other hand, using C<not> with a literal list slice may not
+work. The following previously allowed construct:
+
+ print not (1,2,3)[0];
+
+needs to be written with additional parentheses now:
+
+ print not((1,2,3)[0]);
+
+The behavior remains unaffected when C<not> is not followed by parentheses.
+
+=item Semantics of bareword prototype C<(*)> have changed
+
+Arguments prototyped as C<*> will now be visible within the subroutine
+as either a simple scalar or as a reference to a typeglob. Perl 5.005
+always coerced simple scalar arguments to a typeglob, which wasn't useful
+in situations where the subroutine must distinguish between a simple
+scalar and a typeglob. See L<perlsub/Prototypes>.
+
+=head2 On 64-bit platforms the semantics of bit operators have changed
+
+If your platform is either natively 64-bit or your Perl has been
+configured to used 64-bit integers, i.e., $Config{ivsize} is 8,
+be warned that the semantics of all the bitwise numeric operators
+(& | ^ ~ << >>) have been changed. These operators used to strictly
+operate on the lower 32 bits of integers, but now operate over the
+entire width of native integers. In particular, note that unary C<~>
+will produce different results on platforms that have different
+$Config{ivsize}. For portability, be sure to mask off the excess bits
+in the result of unary C<~>, e.g., C<~$x & 0xffffffff>.
+
=back
=head2 C Source Incompatibilities
=item C<PERL_POLLUTE>
Release 5.005 grandfathered old global symbol names by providing preprocessor
-macros for extension source compatibility. As of release 5.6, these
+macros for extension source compatibility. As of release 5.6.0, these
preprocessor definitions are not available by default. You need to explicitly
compile perl with C<-DPERL_POLLUTE> to get these definitions. For
extensions still using the old symbols, this option can be
=item C<PERL_IMPLICIT_CONTEXT>
+ NOTE: PERL_IMPLICIT_CONTEXT is automatically enabled whenever Perl is built
+ with one of -Dusethreads, -Dusemultiplicity, or both. It is not
+ intended to be enabled by users at this time.
+
This new build option provides a set of macros for all API functions
such that an implicit interpreter/thread context argument is passed to
every API function. As a result of this, something like C<sv_setsv(foo,bar)>
Perl, whose interfaces continue to match those of prior versions
(but subject to the other options described here).
-PERL_IMPLICIT_CONTEXT is automatically enabled whenever Perl is built
-with one of -Dusethreads, -Dusemultiplicity, or both.
-
See L<perlguts/"The Perl API"> for detailed information on the
-ramifications of building Perl using this option.
+ramifications of building Perl with this option.
=item C<PERL_POLLUTE_MALLOC>
-Enabling Perl's malloc in release 5.005 and earlier caused
-the namespace of system versions of the malloc family of functions to
-be usurped by the Perl versions, since by default they used the
-same names.
-
-Besides causing problems on platforms that do not allow these functions to
-be cleanly replaced, this also meant that the system versions could not
-be called in programs that used Perl's malloc. Previous versions of Perl
-have allowed this behaviour to be suppressed with the HIDEMYMALLOC and
-EMBEDMYMALLOC preprocessor definitions.
+Enabling Perl's malloc in release 5.005 and earlier caused the namespace of
+the system's malloc family of functions to be usurped by the Perl versions,
+since by default they used the same names. Besides causing problems on
+platforms that do not allow these functions to be cleanly replaced, this
+also meant that the system versions could not be called in programs that
+used Perl's malloc. Previous versions of Perl have allowed this behaviour
+to be suppressed with the HIDEMYMALLOC and EMBEDMYMALLOC preprocessor
+definitions.
-As of release 5.6, Perl's malloc family of functions have default names
+As of release 5.6.0, Perl's malloc family of functions have default names
distinct from the system versions. You need to explicitly compile perl with
C<-DPERL_POLLUTE_MALLOC> to get the older behaviour. HIDEMYMALLOC
and EMBEDMYMALLOC have no effect, since the behaviour they enabled is now
included (as required before), so there is no source incompatibility
from the change.
-=item Support for C++ exceptions
-
-change#3386, also needs perlguts documentation
-[TODO - Chip Salzenberg <chip@perlsupport.com>]
-
=back
=head2 Binary Incompatibilities
-The default build of this release is binary compatible with the 5.005
-release or its maintenance versions.
+In general, the default build of this release is expected to be binary
+compatible for extensions built with the 5.005 release or its maintenance
+versions. However, specific platforms may have broken binary compatibility
+due to changes in the defaults used in hints files. Therefore, please be
+sure to always check the platform-specific README files for any notes to
+the contrary.
The usethreads or usemultiplicity builds are B<not> binary compatible
with the corresponding builds in 5.005.
+On platforms that require an explicit list of exports (AIX, OS/2 and Windows,
+among others), purely internal symbols such as parser functions and the
+run time opcodes are not exported by default. Perl 5.005 used to export
+all functions irrespective of whether they were considered part of the
+public API or not.
+
+For the full list of public API functions, see L<perlapi>.
+
=head1 Installation and Configuration Improvements
+=head2 -Dusethreads means something different
+
+ WARNING: Support for threads continues to be an experimental feature.
+ Interfaces and implementation are subject to sudden and drastic changes.
+
+The -Dusethreads flag now enables the experimental interpreter-based thread
+support by default. To get the flavor of experimental threads that was in
+5.005 instead, you need to run Configure with "-Dusethreads -Duse5005threads".
+
+As of v5.6.0, interpreter-threads support is still lacking a way to
+create new threads from Perl (i.e., C<use Thread;> will not work with
+interpreter threads). C<use Thread;> continues to be available when you
+specify the -Duse5005threads option to Configure, bugs and all.
+
=head2 New Configure flags
The following new flags may be enabled on the Configure command line
by running Configure with C<-Dflag>.
usemultiplicity
+ usethreads useithreads (new interpreter threads: no Perl API yet)
+ usethreads use5005threads (threads as they were in 5.005)
+
+ use64bitint (equal to now deprecated 'use64bits')
+ use64bitall
uselongdouble
usemorebits
uselargefiles
+ usesocks (only SOCKS v5 supported)
-=head2 -Dusethreads and -Duse64bits now more daring
+=head2 Threadedness and 64-bitness now more daring
The Configure options enabling the use of threads and the use of
-64-bitness are now more daring in the sense that they no more have
-an explicit list of operating systems of known threads/64-bit
+64-bitness are now more daring in the sense that they no more have an
+explicit list of operating systems of known threads/64-bit
capabilities. In other words: if your operating system has the
-necessary APIs, you should be able just to go ahead and use them.
-See also L<"64-bit support">.
+necessary APIs and datatypes, you should be able just to go ahead and
+use them, for threads by Configure -Dusethreads, and for 64 bits
+either explicitly by Configure -Duse64bitint or implicitly if your
+system has 64-bit wide datatypes. See also L<"64-bit support">.
=head2 Long Doubles
=head2 -Dusemorebits
-You can enable both -Duse64bits and -Dlongdouble by -Dusemorebits.
+You can enable both -Duse64bitint and -Duselongdouble with -Dusemorebits.
See also L<"64-bit support">.
=head2 -Duselargefiles
-Some platforms support large files, files larger than two gigabytes.
+Some platforms support system APIs that are capable of handling large files
+(typically, files larger than two gigabytes). Perl will try to use these
+APIs if you ask for -Duselargefiles.
+
See L<"Large file support"> for more information.
=head2 installusrbinperl
=head2 SOCKS support
You can use "Configure -Dusesocks" which causes Perl to probe
-for the SOCKS (v5, not v4) proxy protocol library,
-http://www.socks.nec.com/
+for the SOCKS proxy protocol library (v5, not v4). For more information
+on SOCKS, see:
+
+ http://www.socks.nec.com/
=head2 C<-A> flag
You can "post-edit" the Configure variables using the Configure C<-A>
-flag. The editing happens immediately after the platform specific
+switch. The editing happens immediately after the platform specific
hints files have been processed but before the actual configuration
process starts. Run C<Configure -h> to find out the full C<-A> syntax.
=head2 Enhanced Installation Directories
-The installation structure has been enriched to improve the support for
-maintaining multiple versions of perl, to provide locations for
-vendor-supplied modules and scripts, and to ease maintenance of
-locally-added modules and scripts. See the section on Installation
-Directories in the INSTALL file for complete details. For most users
-building and installing from source, the defaults should be fine.
+The installation structure has been enriched to improve the support
+for maintaining multiple versions of perl, to provide locations for
+vendor-supplied modules, scripts, and manpages, and to ease maintenance
+of locally-added modules, scripts, and manpages. See the section on
+Installation Directories in the INSTALL file for complete details.
+For most users building and installing from source, the defaults should
+be fine.
+
+If you previously used C<Configure -Dsitelib> or C<-Dsitearch> to set
+special values for library directories, you might wish to consider using
+the new C<-Dsiteprefix> setting instead. Also, if you wish to re-use a
+config.sh file from an earlier version of perl, you should be sure to
+check that Configure makes sensible choices for the new directories.
+See INSTALL for complete details.
=head1 Core Changes
=head2 Unicode and UTF-8 support
-Perl can optionally use UTF-8 as its internal representation for character
-strings. The C<utf8> pragma enables this support in the current lexical
-scope. See L<utf8> for more information.
+ WARNING: This is an experimental feature. Implementation details are
+ subject to change.
+
+Perl now uses UTF-8 as its internal representation for character
+strings. The C<utf8> and C<bytes> pragmas are used to control this support
+in the current lexical scope. See L<perlunicode>, L<utf8> and L<bytes> for
+more information.
+
+=head2 Interpreter cloning, threads, and concurrency
+
+ WARNING: This is an experimental feature. Implementation details are
+ subject to change.
+
+Perl 5.005_63 introduces the beginnings of support for running multiple
+interpreters concurrently in different threads. In conjunction with
+the perl_clone() API call, which can be used to selectively duplicate
+the state of any given interpreter, it is possible to compile a
+piece of code once in an interpreter, clone that interpreter
+one or more times, and run all the resulting interpreters in distinct
+threads.
+
+On Windows, this feature is used to emulate fork() at the interpreter
+level. See L<perlfork>.
+
+This feature is still in evolution. It is eventually meant to be used
+to selectively clone a subroutine and data reachable from that
+subroutine in a separate interpreter and run the cloned subroutine
+in a separate thread. Since there is no shared data between the
+interpreters, little or no locking will be needed (unless parts of
+the symbol table are explicitly shared). This is obviously intended
+to be an easy-to-use replacement for the existing threads support.
+
+Support for cloning interpreters and interpreter concurrency can be
+enabled using the -Dusethreads Configure option (see win32/Makefile for
+how to enable it on Windows.) The resulting perl executable will be
+functionally identical to one that was built with -Dmultiplicity, but
+the perl_clone() API call will only be available in the former.
+
+-Dusethreads enables the cpp macro USE_ITHREADS by default, which in turn
+enables Perl source code changes that provide a clear separation between
+the op tree and the data it operates with. The former is immutable, and
+can therefore be shared between an interpreter and all of its clones,
+while the latter is considered local to each interpreter, and is therefore
+copied for each clone.
+
+Note that building Perl with the -Dusemultiplicity Configure option
+is adequate if you wish to run multiple B<independent> interpreters
+concurrently in different threads. -Dusethreads only provides the
+additional functionality of the perl_clone() API call and other
+support for running B<cloned> interpreters concurrently.
=head2 Lexically scoped warning categories
=head2 Lvalue subroutines
-WARNING: This is an experimental feature.
+ WARNING: This is an experimental feature. Details are subject to change.
-change#4081
-[TODO - Ilya Zakharevich <ilya@math.ohio-state.edu>,
-Tuomas Lukka <lukka@fas.harvard.edu>)]
+Subroutines can now return modifiable lvalues.
+See L<perlsub/"Lvalue subroutines">.
=head2 "our" declarations
An "our" declaration introduces a value that can be best understood
as a lexically scoped symbolic alias to a global variable in the
-current package. This is mostly useful as an alternative to the
-C<vars> pragma, but also provides the opportunity to introduce
-typing and other attributes for such variables. See L<perlfunc/our>.
+package that was current where the variable was declared. This is
+mostly useful as an alternative to the C<vars> pragma, but also provides
+the opportunity to introduce typing and other attributes for such
+variables. See L<perlfunc/our>.
+
+=head2 Support for strings represented as a vector of ordinals
+
+Literals of the form C<v1.2.3.4> are now parsed as a string composed of
+of characters with the specified ordinals. This is an alternative, more
+readable way to construct (possibly unicode) strings instead of
+interpolating characters, as in C<"\x{1}\x{2}\x{3}\x{4}">. The leading
+C<v> may be omitted if there are more than two ordinals, so C<1.2.3> is
+parsed the same as C<v1.2.3>.
+
+Strings written in this form are also useful to represent version "numbers".
+It is easy to compare such version "numbers" (which are really just plain
+strings) using any of the usual string comparison operators C<eq>, C<ne>,
+C<lt>, C<gt>, etc., or perform bitwise string operations on them using C<|>,
+C<&>, etc.
+
+In conjunction with the new C<$^V> magic variable (which contains
+the perl version as a string), such literals can be used as a readable way
+to check if you're running a particular version of Perl:
+
+ # this will parse in older versions of Perl also
+ if ($^V and $^V gt v5.6.0) {
+ # new features supported
+ }
+
+C<require> and C<use> also have some special magic to support such literals.
+They will be interpreted as a version rather than as a module name:
+
+ require v5.6.0; # croak if $^V lt v5.6.0
+ use v5.6.0; # same, but croaks at compile-time
+
+Alternatively, the C<v> may be omitted if there is more than one dot:
+
+ require 5.6.0;
+ use 5.6.0;
+
+Also, C<sprintf> and C<printf> support the Perl-specific format flag C<%v>
+to print ordinals of characters in arbitrary strings:
+
+ printf "v%vd", $^V; # prints current version, such as "v5.5.650"
+ printf "%*vX", ":", $addr; # formats IPv6 address
+ printf "%*vb", " ", $bits; # displays bitstring
+
+See L<perldata/"Scalar value constructors"> for additional information.
=head2 Weak references
-WARNING: This is an experimental feature.
+ WARNING: This is an experimental feature.
+
+In previous versions of Perl, you couldn't cache objects so as
+to allow them to be deleted if the last reference from outside
+the cache is deleted. The reference in the cache would hold a
+reference count on the object and the objects would never be
+destroyed.
-change#3385, also need perlguts documentation
+Another familiar problem is with circular references. When an
+object references itself, its reference count would never go
+down to zero, and it would not get destroyed until the program
+is about to exit.
-[TODO - Tuomas Lukka <lukka@fas.harvard.edu>]
+Weak references solve this by allowing you to "weaken" any
+reference, that is, make it not count towards the reference count.
+When the last non-weak reference to an object is deleted, the object
+is destroyed and all the weak references to the object are
+automatically undef-ed.
+
+To use this feature, you need the WeakRef package from CPAN, which
+contains additional documentation.
=head2 File globbing implemented internally
-WARNING: This is currently an experimental feature. Interfaces and
-implementation are likely to change.
+ WARNING: This is currently an experimental feature. Interfaces and
+ implementation are likely to change.
-Perl can be compiled with -DPERL_INTERNAL_GLOB to use the File::Glob
-implementation of the glob() operator. This avoids using an external
-csh process and the problems associated with it.
+Perl now uses the File::Glob implementation of the glob() operator
+automatically. This avoids using an external csh process and the
+problems associated with it.
=head2 Binary numbers supported
Perl now allows the arrow to be omitted in many constructs
involving subroutine calls through references. For example,
-C<$foo[10]->('foo')> may now be written C<$foo[10]('foo')>.
+C<< $foo[10]->('foo') >> may now be written C<$foo[10]('foo')>.
This is rather similar to how the arrow may be omitted from
-C<$foo[10]->{'foo'}>. Note however, that the arrow is still
-required for C<foo(10)->('bar')>.
+C<< $foo[10]->{'foo'} >>. Note however, that the arrow is still
+required for C<< foo(10)->('bar') >>.
+
+=head2 exists() is supported on subroutine names
+
+The exists() builtin now works on subroutine names. A subroutine
+is considered to exist if it has been declared (even if implicitly).
+See L<perlfunc/exists> for examples.
+
+=head2 exists() and delete() are supported on array elements
+
+The exists() and delete() builtins now work on simple arrays as well.
+The behavior is similar to that on hash elements.
+
+exists() can be used to check whether an array element has been
+initialized. This avoids autovivifying array elements that don't exist.
+If the array is tied, the EXISTS() method in the corresponding tied
+package will be invoked.
+
+delete() may be used to remove an element from the array and return
+it. The array element at that position returns to its unintialized
+state, so that testing for the same element with exists() will return
+false. If the element happens to be the one at the end, the size of
+the array also shrinks up to the highest element that tests true for
+exists(), or 0 if none such is found. If the array is tied, the DELETE()
+method in the corresponding tied package will be invoked.
+
+See L<perlfunc/exists> and L<perlfunc/delete> for examples.
=head2 syswrite() ease-of-use
The length argument of C<syswrite()> has become optional.
-=head2 Filehandles can be autovivified
+=head2 File and directory handles can be autovivified
-The construct C<open(my $fh, ...)> can be used to create filehandles
-more easily. The filehandle will be automatically closed at the end
-of the scope of $fh, provided there are no other references to it. This
-largely eliminates the need for typeglobs when opening filehandles
-that must be passed around, as in the following example:
+Similar to how constructs such as C<< $x->[0] >> autovivify a reference,
+handle constructors (open(), opendir(), pipe(), socketpair(), sysopen(),
+socket(), and accept()) now autovivify a file or directory handle
+if the handle passed to them is an uninitialized scalar variable. This
+allows the constructs such as C<open(my $fh, ...)> and C<open(local $fh,...)>
+to be used to create filehandles that will conveniently be closed
+automatically when the scope ends, provided there are no other references
+to them. This largely eliminates the need for typeglobs when opening
+filehandles that must be passed around, as in the following example:
sub myopen {
open my $fh, "@_"
# $f implicitly closed here
}
-[TODO - this idiom needs more pod penetration]
+=head2 open() with more than two arguments
+
+If open() is passed three arguments instead of two, the second arguments
+is used as the mode and the third argument is taken to be the file name.
+This is primarily useful for protecting against unintended magic behavior
+of the traditional two-argument form. See L<perlfunc/open>.
=head2 64-bit support
-All platforms that have 64-bit integers either (a) natively as longs
-or ints (b) via special compiler flags (c) using long long are able to
-use "quads" (64-integers) as follows:
+ NOTE: The Configure flags -Duselonglong and -Duse64bits have been
+ deprecated. Use -Duse64bitint instead.
+
+Any platform that has 64-bit integers either
+
+ (1) natively as longs or ints
+ (2) via special compiler flags
+ (3) using long long or int64_t
+
+are able to use "quads" (64-bit integers) as follows:
=over 4
=item *
-in basic arithmetics: + - * / %
+in basic arithmetics: + - * / % (NOTE: operating close to the limits
+of the integer values may produce surprising results)
+
+=item *
+
+in bit arithmetics: & | ^ ~ << >> (NOTE: these used to be forced
+to be 32 bits wide but now operate on the full native width.)
=item *
-vec() (but see the below note about bit arithmetics)
+vec()
=back
Note that unless you have the case (a) you will have to configure
-and compile Perl using the -Duse64bits Configure flag.
-
-Unfortunately bit arithmetics (&, |, ^, ~, <<, >>) for numbers are not
-64-bit clean, they are explictly forced to be 32-bit. Bit arithmetics
-for bit vectors (created by vec()) are not limited in their width.
+and compile Perl using the -Duse64bitint Configure flag.
+
+There are actually two modes of 64-bitness: the first one is achieved
+using Configure -Duse64bitint and the second one using Configure
+-Duse64bitall. The difference is that the first one is minimal and
+the second one maximal.
+
+The C<use64bitint> does only as much as is required to get 64-bit
+integers into Perl (this may mean, for example, using "long longs")
+while your memory may still be limited to 2 gigabytes (because your
+pointers could still be 32-bit). Note that the name C<64bitint> does
+not imply that your C compiler will be using 64-bit C<int>s (it might,
+but it doesn't have to): the C<use64bitint> means that you will be
+able to have 64 bits wide scalar values.
+
+The C<use64bitall> goes all the way by attempting to switch also
+integers (if it can), longs (and pointers) to being 64-bit. This may
+create an even more binary incompatible Perl than -Duse64bitint: the
+resulting executable may not run at all in a 32-bit box, or you may
+have to reboot/reconfigure/rebuild your operating system to be 64-bit
+aware.
+
+Natively 64-bit systems like Alpha and Cray need neither -Duse64bitint
+nor -Duse64bitall.
Last but not least: note that due to Perl's habit of always using
floating point numbers the quads are still not true integers.
When quads overflow their limits (0...18_446_744_073_709_551_615 unsigned,
-9_223_372_036_854_775_808...9_223_372_036_854_775_807 signed), they
are silently promoted to floating point numbers, after which they will
-start losing precision (their lower digits).
+start losing precision (in their lower digits).
=head2 Large file support
If you have filesystems that support "large files" (files larger than
2 gigabytes), you may now also be able to create and access them from
-Perl. You have to use Configure -Duselargefiles. Turning on the
-large file support turns on also the 64-bit support, for obvious reasons.
+Perl. NOTE: the default action is to use the large file support, if
+available on the platform.
+
+If the large file support is on, and you have a Fcntl constant
+O_LARGEFILE, the O_LARGEFILE is automatically added to the flags
+of sysopen().
+
+Beware: unless your filesystem also supports "sparse files" seeking to
+umpteen petabytes may be unadvisable.
Note that in addition to requiring a proper file system to do large
files you may also need to adjust your per-process (or your
included with the standard Perl distribution) may also be of use, it
offers the getrlimit/setrlimit interface that can be used to adjust
process resource usage limits, including the maximum filesize limit.
-
+
=head2 Long doubles
In some systems you may be able to use long doubles to enhance the
-range of precision of your double precision floating point numbers
+range and precision of your double precision floating point numbers
(that is, Perl's numbers). Use Configure -Duselongdouble to enable
this support (if it is available).
=head2 "more bits"
-You can Configure -Dusemorebits to turn on both the 64-bit support
+You can "Configure -Dusemorebits" to turn on both the 64-bit support
and the long double support.
+=head2 Enhanced support for sort() subroutines
+
+Perl subroutines with a prototype of C<($$)>, and XSUBs in general, can
+now be used as sort subroutines. In either case, the two elements to
+be compared are passed as normal parameters in @_. See L<perlfunc/sort>.
+
+For unprototyped sort subroutines, the historical behavior of passing
+the elements to be compared as the global variables $a and $b remains
+unchanged.
+
=head2 Better syntax checks on parenthesized unary operators
Expressions such as:
Formerly, if you wanted to mark a subroutine as being a method call or
as requiring an automatic lock() when it is entered, you had to declare
that with a C<use attrs> pragma in the body of the subroutine.
-That can now be accomplished with a declaration syntax, like this:
+That can now be accomplished with declaration syntax, like this:
- sub mymethod : locked, method ;
+ sub mymethod : locked method ;
...
- sub mymethod : locked, method {
+ sub mymethod : locked method {
...
}
-F<AutoSplit.pm> and F<SelfLoader.pm> have been updated to keep the attributes
-with the stubs they provide. See L<attributes>.
-
-=head2 Regular expression improvements
-
-change#2827,2373,2372,2365,1813,1800,4112,4158,4215,4301
-[TODO - Ilya Zakharevich <ilya@math.ohio-state.edu>]
+ sub othermethod :locked :method ;
+ ...
+ sub othermethod :locked :method {
+ ...
+ }
-=head2 Overloading improvements
-change#2150
-[TODO - Ilya Zakharevich <ilya@math.ohio-state.edu>]
+(Note how only the first C<:> is mandatory, and whitespace surrounding
+the C<:> is optional.)
-=head2 open() with more than two arguments
-
-[TODO - Ilya Zakharevich <ilya@math.ohio-state.edu>]
+F<AutoSplit.pm> and F<SelfLoader.pm> have been updated to keep the attributes
+with the stubs they provide. See L<attributes>.
=head2 Support for interpolating named characters
-change#4052
-[TODO - Ilya Zakharevich <ilya@math.ohio-state.edu>]
-
-=head2 Experimental support for user-hooks in @INC
-
-[TODO - Ken Fox <kfox@ford.com>]
+The new C<\N> escape interpolates named characters within strings.
+For example, C<"Hi! \N{WHITE SMILING FACE}"> evaluates to a string
+with a unicode smiley face at the end.
=head2 C<require> and C<do> may be overridden
enables perl code to determine whether actions that make sense
only during normal running are warranted. See L<perlvar>.
+=head2 New variable $^V contains Perl version as a string
+
+C<$^V> contains the Perl version number as a string composed of
+characters whose ordinals match the version numbers, i.e. v5.6.0.
+This may be used in string comparisons.
+
+See C<Support for strings represented as a vector of ordinals> for an
+example.
+
=head2 Optional Y2K warnings
If Perl is built with the cpp macro C<PERL_Y2KWARN> defined,
with another number.
This behavior must be specifically enabled when running Configure.
-See L<INSTALL> and L<README.Y2K>.
+See F<INSTALL> and F<README.Y2K>.
=head1 Significant bug fixes
-=head2 E<lt>HANDLEE<gt> on empty files
+=head2 <HANDLE> on empty files
-With C<$/> set to C<undef>, slurping an empty file returns a string of
+With C<$/> set to C<undef>, "slurping" an empty file returns a string of
zero length (instead of C<undef>, as it used to) the first time the
-HANDLE is read. Further reads yield C<undef>.
+HANDLE is read after C<$/> is set to C<undef>. Further reads yield
+C<undef>.
This means that the following will append "foo" to an empty file (it used
to do nothing):
=head2 C<eval '...'> improvements
Line numbers (as reflected by caller() and most diagnostics) within
-C<eval '...'> were often incorrect when here documents were involved.
+C<eval '...'> were often incorrect where here documents were involved.
This has been corrected.
Lexical lookups for variables appearing in C<eval '...'> within
compilation as true errors rather than as warnings. This fixes
cases where error messages leaked through in the form of warnings
when code was compiled at run time using C<eval STRING>, and
-also allows such errors to be reliably trapped using __DIE__ hooks.
+also allows such errors to be reliably trapped using C<eval "...">.
=head2 Automatic flushing of output buffers
fork(), exec(), system(), qx//, and pipe open()s now flush buffers
-of all files opened for output when the operation
-was attempted. This mostly eliminates confusing
-buffering mishaps suffered by users unaware of how Perl internally
-handles I/O.
+of all files opened for output when the operation was attempted. This
+mostly eliminates confusing buffering mishaps suffered by users unaware
+of how Perl internally handles I/O.
+
+This is not supported on some platforms like Solaris where a suitably
+correct implementation of fflush(NULL) isn't available.
=head2 Better diagnostics on meaningless filehandle operations
-Constructs such as C<open(E<lt>FHE<gt>)> and C<close(E<lt>FHE<gt>)>
+Constructs such as C<< open(<FH>) >> and C<< close(<FH>) >>
are compile time errors. Attempting to read from filehandles that
were opened only for writing will now produce warnings (just as
writing to read-only filehandles does).
=head2 Where possible, buffered data discarded from duped input filehandle
-C<open(NEW, "E<lt>&OLD")> now attempts to discard any data that
+C<< open(NEW, "<&OLD") >> now attempts to discard any data that
was previously read and buffered in C<OLD> before duping the handle.
On platforms where doing this is allowed, the next read operation
on C<NEW> will return the same data as the corresponding operation
on C<OLD>. Formerly, it would have returned the data from the start
of the following disk block instead.
+=head2 eof() has the same old magic as <>
+
+C<eof()> would return true if no attempt to read from C<< <> >> had
+yet been made. C<eof()> has been changed to have a little magic of its
+own, it now opens the C<< <> >> files.
+
=head2 system(), backticks and pipe open now reflect exec() failure
On Unix and similar platforms, system(), qx() and open(FOO, "cmd |")
=head2 C<(\$)> prototype and C<$foo{a}>
-An scalar reference prototype now correctly allows a hash or
+A scalar reference prototype now correctly allows a hash or
array element in that slot.
=head2 Pseudo-hashes work better
Dereferencing some types of reference values in a pseudo-hash,
-such as C<$ph->{foo}[1]>, was accidentally disallowed. This has
+such as C<< $ph->{foo}[1] >>, was accidentally disallowed. This has
been corrected.
When applied to a pseudo-hash element, exists() now reports whether
the specified value exists, not merely if the key is valid.
+delete() now works on pseudo-hashes. When given a pseudo-hash element
+or slice it deletes the values corresponding to the keys (but not the keys
+themselves). See L<perlref/"Pseudo-hashes: Using an array as a hash">.
+
+Pseudo-hash slices with constant keys are now optimized to array lookups
+at compile-time.
+
+The C<fields> pragma now provides ways to create pseudo-hashes, via
+fields::new() and fields::phash(). See L<fields>.
+
=head2 C<goto &sub> and AUTOLOAD
The C<goto &sub> construct works correctly when C<&sub> happens
Numbers formatted according to the local numeric locale
(such as using a decimal comma instead of a decimal dot) caused
"isn't numeric" warnings, even while the operations accessing
-those numbers produced correct results. The warnings are gone.
+those numbers produced correct results. These warnings have been
+discontinued.
=head2 Memory leaks
later method lookups from progressing into base packages.
This has been corrected.
-=head2 Consistent numeric conversions
-
-change#3378,3318
-[TODO - Ilya Zakharevich <ilya@math.ohio-state.edu>]
-
=head2 Taint failures under C<-U>
When running in unsafe mode, taint violations could sometimes
behavior, END blocks are not executed anymore when the C<-c> switch
is used.
-Note that something resembling the previous behavior can still be
-obtained by putting C<BEGIN { $^C = 0; exit; } at the very end of
-the top level source file.
+See L<CHECK blocks> for how to run things when the compile phase ends.
=head2 Potential to leak DATA filehandles
used to truncate the message in prior versions.
$foo::a and $foo::b are now exempt from "possible typo" warnings only
-if sort() is encountered in package foo.
+if sort() is encountered in package C<foo>.
Unrecognized alphabetic escapes encountered when parsing quote
constructs now generate a warning, since they may take on new
optimized to directly set the lexical variable on the LHS,
eliminating redundant copying overheads.
-=head2 Method lookups optimized
-
-[TODO - Chip Salzenberg <chip@perlsupport.com>]
-
-=head2 Faster mechanism to invoke XSUBs
-
-change#4044,4125
-[TODO - Ilya Zakharevich <ilya@math.ohio-state.edu>]
-
-=head2 Perl_malloc() improvements
-
-change#4237
-[TODO - Ilya Zakharevich <ilya@math.ohio-state.edu>]
-
=head2 Faster subroutine calls
Minor changes in how subroutine calls are handled internally
=head1 Platform specific changes
-=head2 Additional supported platforms
+=head2 Supported platforms
=over 4
=item *
-Rhapsody is now supported.
+Rhapsody/Darwin is now supported.
=item *
=head2 DOS
-[TODO - Laszlo Molnar <laszlo.molnar@eth.ericsson.se>]
+=over 4
+
+=item *
+
+Perl now works with djgpp 2.02 (and 2.03 alpha).
+
+=item *
+
+Environment variable names are not converted to uppercase any more.
+
+=item *
+
+Incorrect exit codes from backticks have been fixed.
-=head2 OS/2
+=item *
+
+This port continues to use its own builtin globbing (not File::Glob).
+
+=back
-[TODO - Ilya Zakharevich <ilya@math.ohio-state.edu>]
+=head2 OS390 (OpenEdition MVS)
+
+Support for this EBCDIC platform has not been renewed in this release.
+There are difficulties in reconciling Perl's standardization on UTF-8
+as its internal representation for characters with the EBCDIC character
+set, because the two are incompatible.
+
+It is unclear whether future versions will renew support for this
+platform, but the possibility exists.
=head2 VMS
-[TODO - Charles Bailey <bailey@newman.upenn.edu>]
+Numerous revisions and extensions to configuration, build, testing, and
+installation process to accomodate core changes and VMS-specific options.
+
+Expand %ENV-handling code to allow runtime mapping to logical names,
+CLI symbols, and CRTL environ array.
+
+Extension of subprocess invocation code to accept filespecs as command
+"verbs".
+
+Add to Perl command line processing the ability to use default file types and
+to recognize Unix-style C<2E<gt>&1>.
+
+Expansion of File::Spec::VMS routines, and integration into ExtUtils::MM_VMS.
+
+Extension of ExtUtils::MM_VMS to handle complex extensions more flexibly.
+
+Barewords at start of Unix-syntax paths may be treated as text rather than
+only as logical names.
+
+Optional secure translation of several logical names used internally by Perl.
+
+Miscellaneous bugfixing and porting of new core code to VMS.
+
+Thanks are gladly extended to the many people who have contributed VMS
+patches, testing, and ideas.
=head2 Win32
-Site library searches failed to look for ".../site/5.XXX/lib"
-if ".../site/5.XXXYY/lib" wasn't found. This has been corrected.
+Perl can now emulate fork() internally, using multiple interpreters running
+in different concurrent threads. This support must be enabled at build
+time. See L<perlfork> for detailed information.
-When given a pathname that consists only of a drivename, such
-as C<A:>, opendir() and stat() now use the current working
-directory for the drive rather than the drive root.
+When given a pathname that consists only of a drivename, such as C<A:>,
+opendir() and stat() now use the current working directory for the drive
+rather than the drive root.
-The builtin XSUB functions in the Win32:: namespace are
-documented. See L<Win32>.
+The builtin XSUB functions in the Win32:: namespace are documented. See
+L<Win32>.
$^X now contains the full path name of the running executable.
handles. kill() accepts any real process id, rather than strictly
return values from system(1,...).
+For better compatibility with Unix, C<kill(0, $pid)> can now be used to
+test whether a process exists.
+
The C<Shell> module is supported.
-Rudimentary support for building under command.com in Windows 95
+Better support for building Perl under command.com in Windows 95
has been added.
-[TODO - GSAR]
+Scripts are read in binary mode by default to allow ByteLoader (and
+the filter mechanism in general) to work properly. For compatibility,
+the DATA filehandle will be set to text mode if a carriage return is
+detected at the end of the line containing the __END__ or __DATA__
+token; if not, the DATA filehandle will be left open in binary mode.
+Earlier versions always opened the DATA filehandle in text mode.
+
+The glob() operator is implemented via the C<File::Glob> extension,
+which supports glob syntax of the C shell. This increases the flexibility
+of the glob() operator, but there may be compatibility issues for
+programs that relied on the older globbing syntax. If you want to
+preserve compatibility with the older syntax, you might want to run
+perl with C<-MFile::DosGlob>. For details and compatibility information,
+see L<File::Glob>.
=head1 New tests
Compatibility tests for C<sub : attrs> vs the older C<use attrs>.
+=item lib/env
+
+Tests for new environment scalar capability (e.g., C<use Env qw($BAR);>).
+
+=item lib/env-array
+
+Tests for new environment array capability (e.g., C<use Env qw(@PATH);>).
+
=item lib/io_const
IO constants (SEEK_*, _IO*).
Verify operations that access pad objects (lexicals and temporaries).
+=item op/exists_sub
+
+Verify C<exists &sub> operations.
+
=back
=head1 Modules and Pragmata
=item B
-The Perl Compiler suite has been extensively reworked for this
-release.
+ WARNING: The Compiler suite remains highly experimental. The
+ generated code may not be correct, even it manages to execute
+ without errors.
-[TODO - Vishal Bhatia <vishal@gol.com>,
-Nick Ing-Simmons <nick@ni-s.u-net.com>]
+The Perl Compiler suite has been extensively reworked for this
+release. More of the standard Perl testsuite passes when run
+under the Compiler, but there is still a significant way to
+go to achieve production quality compiled executables.
=item ByteLoader
=item constant
-References can now be used. See L<constant>.
+References can now be used.
+
+The new version also allows a leading underscore in constant names, but
+disallows a double leading underscore (as in "__LINE__"). Some other names
+are disallowed or warned against, including BEGIN, END, etc. Some names
+which were forced into main:: used to fail silently in some cases; now they're
+fatal (outside of main::) and an optional warning (inside of main::).
+The ability to detect whether a constant had been set with a given name has
+been added.
+
+See L<constant>.
=item charnames
-change#4052
-[TODO - Ilya Zakharevich <ilya@math.ohio-state.edu>]
+This pragma implements the C<\N> string escape. See L<charnames>.
=item Data::Dumper
A C<Maxdepth> setting can be specified to avoid venturing
too deeply into deep data structures. See L<Data::Dumper>.
+The XSUB implementation of Dump() is now automatically called if the
+C<Useqq> setting is not in use.
+
Dumping C<qr//> objects works correctly.
=item DB
=item DB_File
-[TODO - Paul Marquess <paul.marquess@bt.com>]
+DB_File can now be built with Berkeley DB versions 1, 2 or 3.
+See C<ext/DB_File/Changes>.
=item Devel::DProf
-Devel::DProf, a Perl source code profiler has been added. See L<DProf>.
+Devel::DProf, a Perl source code profiler has been added. See
+L<Devel::DProf> and L<dprofpp>.
=item Dumpvalue
=item Benchmark
+Overall, Benchmark results exhibit lower average error and better timing
+accuracy.
+
You can now run tests for I<n> seconds instead of guessing the right
-number of tests to run: e.g. timethese(-5, ...) will run each
+number of tests to run: e.g., timethese(-5, ...) will run each
code for at least 5 CPU seconds. Zero as the "number of repetitions"
means "for at least 3 CPU seconds". The output format has also
changed. For example:
-use Benchmark;$x=3;timethese(-5,{a=>sub{$x*$x},b=>sub{$x**2}})
+ use Benchmark;$x=3;timethese(-5,{a=>sub{$x*$x},b=>sub{$x**2}})
will now output something like this:
-Benchmark: running a, b, each for at least 5 CPU seconds...
- a: 5 wallclock secs ( 5.77 usr + 0.00 sys = 5.77 CPU) @ 200551.91/s (n=1156516)
- b: 4 wallclock secs ( 5.00 usr + 0.02 sys = 5.02 CPU) @ 159605.18/s (n=800686)
+ Benchmark: running a, b, each for at least 5 CPU seconds...
+ a: 5 wallclock secs ( 5.77 usr + 0.00 sys = 5.77 CPU) @ 200551.91/s (n=1156516)
+ b: 4 wallclock secs ( 5.00 usr + 0.02 sys = 5.02 CPU) @ 159605.18/s (n=800686)
New features: "each for at least N CPU seconds...", "wallclock secs",
and the "@ operations/CPU second (n=operations)".
-change#4265,4266,4292
-[TODO - Barrie Slaymaker <barries@slaysys.com>]
+timethese() now returns a reference to a hash of Benchmark objects containing
+the test results, keyed on the names of the tests.
+
+timethis() now returns the iterations field in the Benchmark result object
+instead of 0.
+
+timethese(), timethis(), and the new cmpthese() (see below) can also take
+a format specifier of 'none' to suppress output.
+
+A new function countit() is just like timeit() except that it takes a
+TIME instead of a COUNT.
+
+A new function cmpthese() prints a chart comparing the results of each test
+returned from a timethese() call. For each possible pair of tests, the
+percentage speed difference (iters/sec or seconds/iter) is shown.
+
+For other details, see L<Benchmark>.
=item Devel::Peek
The Devel::Peek module provides access to the internal representation
of Perl variables and data. It is a data debugging tool for the XS programmer.
-=item ExtUtils::MakeMaker
+=item English
-change#4135, also needs docs in module pod
-[TODO - Ilya Zakharevich <ilya@math.ohio-state.edu>]
+$PERL_VERSION now stands for C<$^V> (a string value) rather than for C<$]>
+(a numeric value).
+
+=item Env
+
+Env now supports accessing environment variables like PATH as array
+variables.
=item Fcntl
More Fcntl constants added: F_SETLK64, F_SETLKW64, O_LARGEFILE for
-large (more than 4G) file access (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.
+large file (more than 4GB) access (NOTE: the O_LARGEFILE is
+automatically added to sysopen() flags if large file support has been
+configured, as is the default), Free/Net/OpenBSD locking behaviour
+flags F_FLOCK, F_POSIX, Linux F_SHLCK, and O_ACCMODE: the combined
+mask of O_RDONLY, O_WRONLY, and O_RDWR. The seek()/sysseek()
+constants SEEK_SET, SEEK_CUR, and SEEK_END are available via the
+C<:seek> tag. The chmod()/stat() S_IF* constants and S_IS* functions
+are available via the C<:mode> tag.
=item File::Compare
A bug that caused File::Find to lose track of the working directory
when pruning top-level directories has been fixed.
+File::Find now also supports several other options to control its
+behavior. It can follow symbolic links if the C<follow> option is
+specified. Enabling the C<no_chdir> option will make File::Find skip
+changing the current directory when walking directories. The C<untaint>
+flag can be useful when running with taint checks enabled.
+
+See L<File::Find>.
+
=item File::Glob
-This extension implements BSD-style file globbing. It will also be
-used for the internal implementation of the glob() operator if
-Perl was compiled with -DPERL_INTERNAL_GLOB. See L<File::Glob>.
+This extension implements BSD-style file globbing. By default,
+it will also be used for the internal implementation of the glob()
+operator. See L<File::Glob>.
=item File::Spec
See L<Pod::Usage> for details.
-A bug that prevented the non-option call-back E<lt>E<gt> from being
+A bug that prevented the non-option call-back <> from being
specified as the first argument has been fixed.
-To specify the characters E<lt> and E<gt> as option starters, use
-E<gt>E<lt>. Note, however, that changing option starters is strongly
-deprecated.
+To specify the characters < and > as option starters, use ><. Note,
+however, that changing option starters is strongly deprecated.
=item IO
A bug that prevented the IO::Socket::protocol() accessor
from ever returning the correct value has been corrected.
+IO::Socket::connect now uses non-blocking IO instead of alarm()
+to do connect timeouts.
+
+IO::Socket::accept now uses select() instead of alarm() for doing
+timeouts.
+
+IO::Socket::INET->new now sets $! correctly on failure. $@ is
+still set for backwards compatability.
+
=item JPL
Java Perl Lingo is now distributed with Perl. See jpl/README
=item Math::BigInt
-The bitwise operations C<E<lt>E<lt>>, C<E<gt>E<gt>>, C<&>, C<|>,
+The bitwise operations C<<< << >>>, C<<< >> >>>, C<&>, C<|>,
and C<~> are now supported on bigints.
=item Math::Complex
The accessor methods Re, Im, arg, abs, rho, and theta can now also
act as mutators (accessor $z->Re(), mutator $z->Re(3)).
+The class method C<display_format> and the corresponding object method
+C<display_format>, in addition to accepting just one argument, now can
+also accept a parameter hash. Recognized keys of a parameter hash are
+C<"style">, which corresponds to the old one parameter case, and two
+new parameters: C<"format">, which is a printf()-style format string
+(defaults usually to C<"%.15g">, you can revert to the default by
+setting the format string to C<undef>) used for both parts of a
+complex number, and C<"polar_pretty_print"> (defaults to true),
+which controls whether an attempt is made to try to recognize small
+multiples and rationals of pi (2pi, pi/2) at the argument (angle) of a
+polar complex number.
+
+The potentially disruptive change is that in list context both methods
+now I<return the parameter hash>, instead of only the value of the
+C<"style"> parameter.
+
=item Math::Trig
A little bit of radial trigonometry (cylindrical and spherical),
radial coordinate conversions, and the great circle distance were added.
-=item Pod::Parser
+=item Pod::Parser, Pod::InputObjects
+
+Pod::Parser is a base class for parsing and selecting sections of
+pod documentation from an input stream. This module takes care of
+identifying pod paragraphs and commands in the input and hands off the
+parsed paragraphs and commands to user-defined methods which are free
+to interpret or translate them as they see fit.
+
+Pod::InputObjects defines some input objects needed by Pod::Parser, and
+for advanced users of Pod::Parser that need more about a command besides
+its name and text.
+
+As of release 5.6.0 of Perl, Pod::Parser is now the officially sanctioned
+"base parser code" recommended for use by all pod2xxx translators.
+Pod::Text (pod2text) and Pod::Man (pod2man) have already been converted
+to use Pod::Parser and efforts to convert Pod::HTML (pod2html) are already
+underway. For any questions or comments about pod parsing and translating
+issues and utilities, please use the pod-people@perl.org mailing list.
+
+For further information, please see L<Pod::Parser> and L<Pod::InputObjects>.
+
+=item Pod::Checker, podchecker
+
+This utility checks pod files for correct syntax, according to
+L<perlpod>. Obvious errors are flagged as such, while warnings are
+printed for mistakes that can be handled gracefully. The checklist is
+not complete yet. See L<Pod::Checker>.
+
+=item Pod::ParseUtils, Pod::Find
+
+These modules provide a set of gizmos that are useful mainly for pod
+translators. L<Pod::Find|Pod::Find> traverses directory structures and
+returns found pod files, along with their canonical names (like
+C<File::Spec::Unix>). L<Pod::ParseUtils|Pod::ParseUtils> contains
+B<Pod::List> (useful for storing pod list information), B<Pod::Hyperlink>
+(for parsing the contents of C<LE<lt>E<gt>> sequences) and B<Pod::Cache>
+(for caching information about pod files, e.g., link nodes).
-[TODO - Brad Appleton <bradapp@enteract.com>]
+=item Pod::Select, podselect
+
+Pod::Select is a subclass of Pod::Parser which provides a function
+named "podselect()" to filter out user-specified sections of raw pod
+documentation from an input stream. podselect is a script that provides
+access to Pod::Select from other scripts to be used as a filter.
+See L<Pod::Select>.
+
+=item Pod::Usage, pod2usage
+
+Pod::Usage provides the function "pod2usage()" to print usage messages for
+a Perl script based on its embedded pod documentation. The pod2usage()
+function is generally useful to all script authors since it lets them
+write and maintain a single source (the pods) for documentation, thus
+removing the need to create and maintain redundant usage message text
+consisting of information already in the pods.
+
+There is also a pod2usage script which can be used from other kinds of
+scripts to print usage messages from pods (even for non-Perl scripts
+with pods embedded in comments).
+
+For details and examples, please see L<Pod::Usage>.
=item Pod::Text and Pod::Man
-[TODO - Russ Allbery <rra@stanford.edu>]
+Pod::Text has been rewritten to use Pod::Parser. While pod2text() is
+still available for backwards compatibility, the module now has a new
+preferred interface. See L<Pod::Text> for the details. The new Pod::Text
+module is easily subclassed for tweaks to the output, and two such
+subclasses (Pod::Text::Termcap for man-page-style bold and underlining
+using termcap information, and Pod::Text::Color for markup with ANSI color
+sequences) are now standard.
+
+pod2man has been turned into a module, Pod::Man, which also uses
+Pod::Parser. In the process, several outstanding bugs related to quotes
+in section headers, quoting of code escapes, and nested lists have been
+fixed. pod2man is now a wrapper script around this module.
=item SDBM_File
happens to be read from the database in a single FETCH() has been
fixed.
+=item Sys::Syslog
+
+Sys::Syslog now uses XSUBs to access facilities from syslog.h so it
+no longer requires syslog.ph to exist.
+
+=item Sys::Hostname
+
+Sys::Hostname now uses XSUBs to call the C library's gethostname() or
+uname() if they exist.
+
+=item Term::ANSIColor
+
+Term::ANSIColor is a very simple module to provide easy and readable
+access to the ANSI color and highlighting escape sequences, supported by
+most ANSI terminal emulators. It is now included standard.
+
=item Time::Local
The timelocal() and timegm() functions used to silently return bogus
backward-compatibility. It's been replaced by the C<sub : attributes>
syntax. See L<perlsub/"Subroutine Attributes"> and L<attributes>.
-C<use utf8> to enable UTF-8 and Unicode support.
-
-C<use caller 'encoding'> allows modules to inherit pragmatic attributes
-from the caller's context. C<encoding> is currently the only supported
-attribute.
-
Lexical warnings pragma, C<use warnings;>, to control optional warnings.
See L<perllexwarn>.
=head1 Utility Changes
-=head2 h2ph
-
-[TODO - Kurt Starsinic <kstar@chapin.edu>]
-
=head2 perlcc
C<perlcc> now supports the C and Bytecode backends. By default,
Support for non-Unix platforms has been improved.
-=head2 h2xs
-
-change#4232
-[TODO - Ilya Zakharevich <ilya@math.ohio-state.edu>]
-
=head1 Documentation Changes
=over 4
+=item perlapi.pod
+
+The official list of public Perl API functions.
+
=item perlcompile.pod
An introduction to using the Perl Compiler suite.
+=item perlfilter.pod
+
+An introduction to writing Perl source filters.
+
=item perlhack.pod
Some guidelines for hacking the Perl source code.
+=item perlintern.pod
+
+A list of internal functions in the Perl source code.
+(List is currently empty.)
+
=item perlopentut.pod
A tutorial on using open() effectively.
A tutorial that introduces the essentials of references.
+=item perlboot.pod
+
+A tutorial for beginners on object-oriented Perl.
+
=item perltootc.pod
A tutorial on managing class data for object modules.
+=item perlunicode.pod
+
+An introduction to Unicode support features in Perl.
+
=back
=head1 New or Changed Diagnostics
=over 4
+=item "%s" variable %s masks earlier declaration in same %s
+
+(W) A "my" or "our" variable has been redeclared in the current scope or statement,
+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 "my sub" not yet implemented
(F) Lexically scoped subroutines are not yet implemented. Don't try that
yet.
+=item "our" variable %s redeclared
+
+(W) You seem to have already declared the same global once before in the
+current lexical scope.
+
=item '!' allowed only after types %s
(F) The '!' is allowed in pack() and unpack() only after certain types.
but this did not follow some numeric unpack specification.
See L<perlfunc/pack>.
-=item Repeat count in pack overflows
-
-(F) You can't specify a repeat count so large that it overflows
-your signed integers. See L<perlfunc/pack>.
-
-=item Repeat count in unpack overflows
-
-(F) You can't specify a repeat count so large that it overflows
-your signed integers. See L<perlfunc/unpack>.
-
=item /%s/: Unrecognized escape \\%c passed through
(W) You used a backslash-character combination which is not recognized
if you are certain that you're calling the function correctly, you may put
an ampersand before the name to avoid the warning. See L<perlsub>.
+=item %s argument is not a HASH or ARRAY element
+
+(F) The argument to exists() must be a hash or array element, such as:
+
+ $foo{$bar}
+ $ref->[12]->["susie"]
+
+=item %s argument is not a HASH or ARRAY element or slice
+
+(F) The argument to delete() must be either a hash or array element, such as:
+
+ $foo{$bar}
+ $ref->[12]->["susie"]
+
+or a hash or array slice, such as:
+
+ @foo[$bar, $baz, $xyzzy]
+ @{$ref->[12]}{"susie", "queue"}
+
+=item %s argument is not a subroutine name
+
+(F) The argument to exists() for C<exists &sub> must be a subroutine
+name, and not a subroutine call. C<exists &sub()> will generate this error.
+
=item %s package attribute may clash with future reserved word: %s
(W) A lowercase attribute name was used that had a package-specific handler.
=item <> should be quotes
-(F) You wrote C<require E<lt>fileE<gt>> when you should have written
+(F) You wrote C<< require <file> >> when you should have written
C<require 'file'>.
=item Attempt to join self
malloc()ed in the first place. Mandatory, but can be disabled by
setting environment variable C<PERL_BADFREE> to 1.
+=item Bareword found in conditional
+
+(W) The compiler found a bareword where it expected a conditional,
+which often indicates that an || or && was parsed as part of the
+last argument of the previous construct, for example:
+
+ open FOO || die;
+
+It may also indicate a misspelled constant that has been interpreted
+as a bareword:
+
+ use constant TYPO => 1;
+ if (TYOP) { print "foo" }
+
+The C<strict> pragma is useful in avoiding such errors.
+
=item Binary number > 0b11111111111111111111111111111111 non-portable
(W) The binary number you specified is larger than 2**32-1
(P) For some reason you can't check the filesystem of the script for nosuid.
+=item Can't declare class for non-scalar %s in "%s"
+
+(S) Currently, only scalar variables can declared with a specific class
+qualifier in a "my" or "our" declaration. The semantics may be extended
+for other types of variables in future.
+
+=item Can't declare %s in "%s"
+
+(F) Only scalar, array, and hash variables may be declared as "my" or
+"our" variables. They must have ordinary identifiers as names.
+
+=item Can't ignore signal CHLD, forcing to default
+
+(W) Perl has detected that it is being run with the SIGCHLD signal
+(sometimes known as SIGCLD) disabled. Since disabling this signal
+will interfere with proper determination of exit status of child
+processes, Perl has reset the signal to its default value.
+This situation typically indicates that the parent program under
+which Perl may be running (e.g., cron) is being very careless.
+
=item Can't modify non-lvalue subroutine call
(F) Subroutines meant to be used in lvalue context should be declared as
(F) Compile-time-substitutions (such as overloaded constants and
character names) were not correctly set up.
+=item CORE::%s is not a keyword
+
+(F) The CORE:: namespace is reserved for Perl keywords.
+
=item defined(@array) is deprecated
(D) defined() is not usually useful on arrays because it checks for an
See Server error.
+=item Did you mean "local" instead of "our"?
+
+(W) Remember that "our" does not localize the declared global variable.
+You have declared it again in the same lexical scope, which seems superfluous.
+
=item Document contains no data
See Server error.
(W) You tried to read from a filehandle opened only for writing. If you
intended it to be a read/write filehandle, you needed to open it with
-"+E<lt>" or "+E<gt>" or "+E<gt>E<gt>" instead of with "E<lt>" or nothing. If
-you intended only to read from the file, use "E<lt>". See
+"+<" or "+>" or "+>>" instead of with "<" or nothing. If
+you intended only to read from the file, use "<". See
L<perlfunc/open>.
+=item flock() on closed filehandle %s
+
+(W) The filehandle you're attempting to flock() got itself closed some
+time before now. Check your logic flow. flock() operates on filehandles.
+Are you attempting to call flock() on a dirhandle by the same name?
+
+=item Global symbol "%s" requires explicit package name
+
+(F) You've said "use strict vars", which indicates that all variables
+must either be lexically scoped (using "my"), declared beforehand using
+"our", or explicitly qualified to say which package the global variable
+is in (using "::").
+
=item Hexadecimal number > 0xffffffff non-portable
(W) The hexadecimal number you specified is larger than 2**32-1
=item Invalid separator character %s in attribute list
-(F) Something other than a comma or whitespace was seen between the
+(F) Something other than a colon or whitespace was seen between the
elements of an attribute list. If the previous attribute
had a parenthesised parameter list, perhaps that list was terminated
too soon. See L<attributes>.
=item Invalid separator character %s in subroutine attribute list
-(F) Something other than a comma or whitespace was seen between the
+(F) Something other than a colon or whitespace was seen between the
elements of a subroutine attribute list. If the previous attribute
had a parenthesised parameter list, perhaps that list was terminated
too soon.
(F) The reserved syntax for lexically scoped subroutines requires that they
have a name with which they can be found.
+=item No %s specified for -%c
+
+(F) The indicated command line switch needs a mandatory argument, but
+you haven't specified one.
+
+=item No package name allowed for variable %s in "our"
+
+(F) Fully qualified variable names are not allowed in "our" declarations,
+because that doesn't make much sense under existing semantics. Such
+syntax is reserved for future extensions.
+
+=item No space allowed after -%c
+
+(F) The argument to the indicated command line switch must follow immediately
+after the switch, without intervening spaces.
+
=item no UTC offset information; assuming local time is UTC
(S) A warning peculiar to VMS. Perl was unable to find the local
(P) Failed an internal consistency check while trying to reset all weak
references to an object.
+=item Parentheses missing around "%s" list
+
+(W) You said something like
+
+ my $foo, $bar = @_;
+
+when you meant
+
+ my ($foo, $bar) = @_;
+
+Remember that "my", "our", and "local" bind tighter than comma.
+
=item Possible Y2K bug: %s
(W) You are concatenating the number 19 with another number, which
See Server error.
+=item Repeat count in pack overflows
+
+(F) You can't specify a repeat count so large that it overflows
+your signed integers. See L<perlfunc/pack>.
+
+=item Repeat count in unpack overflows
+
+(F) You can't specify a repeat count so large that it overflows
+your signed integers. See L<perlfunc/unpack>.
+
=item realloc() of freed memory ignored
(S) An internal routine called realloc() on something that had already
=item Unknown open() mode '%s'
(F) The second argument of 3-argument open() is not among the list
-of valid modes: C<L<lt>>, C<L<gt>>, C<E<gt>E<gt>>, C<+L<lt>>,
-C<+L<gt>>, C<+E<gt>E<gt>>, C<-|>, C<|->.
+of valid modes: C<< < >>, C<< > >>, C<<< >> >>>, C<< +< >>,
+C<< +> >>, C<<< +>> >>>, C<-|>, C<|->.
=item Unknown process %x sent message to prime_env_iter: %s
might directly modify logical name tables and introduce nonstandard names,
or it may indicate that a logical name table has been corrupted.
+=item Probable precedence problem on %s
+
+(W) The compiler found a bareword where it expected a conditional,
+which often indicates that an || or && was parsed as part of the
+last argument of the previous construct, for example:
+
+ open FOO || die;
+
=item regexp too big
(F) The current implementation of regular expressions uses shorts as
Home Page.
If you believe you have an unreported bug, please run the B<perlbug>
-program included with your release. Make sure to trim your bug down
+program included with your release. Be sure to 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 perlbug@perl.com to be
analysed by the Perl porting team.
https://perl5.git.perl.org / perl5.git / blobdiff