=head1 NAME
-perldelta - what's new for perl v5.6 (as of v5.005_64)
+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
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 delete(), values() and C<\(%h)> operate on aliases to values, not copies
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>
-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.
+ 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
(but subject to the other options described here).
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
=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.
+ 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 ask for -Duse5005threads.
+5.005 instead, you need to run Configure with "-Dusethreads -Duse5005threads".
-As of v5.5.640, interpreter-threads support is still lacking a way to
+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
-ask for -Duse5005threads, bugs and all.
-
-=head2 Perl's version numbering has changed
-
-Beginning with Perl version 5.6, the version number convention has been
-changed to a "dotted tuple" 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 will be numbered v5.7.x,
-beginning with v5.7.0, and the next major production release following
-v5.6 will be v5.8.
-
-The v1.2.3 syntax is also now legal in Perl. See L<Support for version tuples>
-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 have been incrementing the subversion component in multiples of
-10. Versions after v5.6 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 will be v5.6.1, which amounts to a floating point
-value of 5.006_001).
+specify the -Duse5005threads option to Configure, bugs and all.
=head2 New Configure flags
by running Configure with C<-Dflag>.
usemultiplicity
- use5005threads
+ 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 in a pre-alpha state. Use
-at your own risk.
+ 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
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 macros USE_ITHREADS by default, which enables
-Perl source code changes that provide a clear separation between the op tree
-and the data it operates with. The former is considered 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.
+-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
additional functionality of the perl_clone() API call and other
support for running B<cloned> interpreters concurrently.
-[XXX TODO - the Compiler backends may be broken when USE_ITHREADS is
-enabled.]
-
=head2 Lexically scoped warning categories
You can now control the granularity of warnings emitted by perl at a finer
=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
the opportunity to introduce typing and other attributes for such
variables. See L<perlfunc/our>.
-=head2 Support for version tuples
+=head2 Support for strings represented as a vector of ordinals
-Literals of the form v1.2.3.4 are now parsed as the utf8 string
-C<"\x{1}\x{2}\x{3}\x{4}">. This allows comparing version numbers using
-regular string comparison operators C<eq>, C<ne>, C<lt>, C<gt> etc.
+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>.
-These "dotted tuples" are dual-valued. They are both strings of utf8
-characters, and floating point numbers. Thus v1.2.3.4 has the string
-value C<"\x{1}\x{2}\x{3}\x{4}"> and the numeric value 1.002_003_004.
-As another example, v5.5.640 has the string value C<"\x{5}\x{5}\x{280}">
-(remember 280 hexadecimal is 640 decimal) and the numeric value
-5.005_64.
+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 in this format), such literals can be used to
-check if you're running a particular version of Perl.
+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:
- if ($^V and $^V gt v5.5.640) {
- # new style version numbers are supported
+ # this will parse in older versions of Perl also
+ if ($^V and $^V gt v5.6.0) {
+ # new features supported
}
-C<require> and C<use> also support such literals:
+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
+ 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", " ", $bits; # displays bitstring
+
+See L<perldata/"Scalar value constructors"> for additional information.
=head2 Weak references
-WARNING: This is an experimental feature.
+ WARNING: This is an experimental feature.
-change#3385, also need perlguts documentation
+In previous versions of Perl, you couldn't cache objects so as
+to allow them to be deleted if the last reference from outside
+the cache is deleted. The reference in the cache would hold a
+reference count on the object and the objects would never be
+destroyed.
-[TODO - Tuomas Lukka <lukka@fas.harvard.edu>]
+Another familiar problem is with circular references. When an
+object references itself, its reference count would never go
+down to zero, and it would not get destroyed until the program
+is about to exit.
+
+Weak references solve this by allowing you to "weaken" any
+reference, that is, make it not count towards the reference count.
+When the last non-weak reference to an object is deleted, the object
+is destroyed and all the weak references to the object are
+automatically undef-ed.
+
+To use this feature, you need the WeakRef package from CPAN, which
+contains additional documentation.
=head2 File globbing implemented internally
-WARNING: This is currently an experimental feature. Interfaces and
-implementation are likely to change.
+ WARNING: This is currently an experimental feature. Interfaces and
+ implementation are likely to change.
Perl now uses the File::Glob implementation of the glob() operator
automatically. This avoids using an external csh process and the
Perl now allows the arrow to be omitted in many constructs
involving subroutine calls through references. For example,
-C<$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<< $foo[10]->{'foo'} >>. Note however, that the arrow is still
+required for C<< foo(10)->('bar') >>.
=head2 exists() is supported on subroutine names
The behavior is similar to that on hash elements.
exists() can be used to check whether an array element has been
-initialized without autovivifying it. If the array is tied, the
-EXISTS() method in the corresponding tied package will be invoked.
+initialized. This avoids autovivifying array elements that don't exist.
+If the array is tied, the EXISTS() method in the corresponding tied
+package will be invoked.
delete() may be used to remove an element from the array and return
it. The array element at that position returns to its unintialized
state, so that testing for the same element with exists() will return
false. If the element happens to be the one at the end, the size of
-the array also shrinks by one. If the array is tied, the DELETE() method
-in the corresponding tied package will be invoked.
+the array also shrinks up to the highest element that tests true for
+exists(), or 0 if none such is found. If the array is tied, the DELETE()
+method in the corresponding tied package will be invoked.
See L<perlfunc/exists> and L<perlfunc/delete> for examples.
=head2 File and directory handles can be autovivified
-Similar to how constructs such as C<$x->[0]> autovivify a reference,
+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
# $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.
+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 on many platforms.
-Beware that unless your filesystem also supports "sparse files" seeking
-to umpteen petabytes may be unadvisable.
+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
=head2 Enhanced support for sort() subroutines
-Perl subroutines with a prototype of C<($$)> and XSUBs in general can
+Perl subroutines with a prototype of C<($$)>, 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>.
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>]
-
-=head2 Overloading improvements
-
-change#2150
-[TODO - Ilya Zakharevich <ilya@math.ohio-state.edu>]
-
-=head2 open() with more than two arguments
-
-[TODO - Ilya Zakharevich <ilya@math.ohio-state.edu>]
-
=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 in v5.6.0 format
+=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.
-C<$^V> contains the Perl version number as a version tuple that
-can be used in string or numeric comparisons. See
-C<Support for version tuples> for an example.
+See C<Support for strings represented as a vector of ordinals> for an
+example.
=head2 Optional Y2K warnings
with another number.
This behavior must be specifically enabled when running Configure.
-See L<INSTALL> and L<README.Y2K>.
+See F<INSTALL> and F<README.Y2K>.
=head1 Significant bug fixes
-=head2 E<lt>HANDLEE<gt> on empty files
+=head2 <HANDLE> on empty files
With C<$/> set to C<undef>, "slurping" an empty file returns a string of
zero length (instead of C<undef>, as it used to) the first time the
=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
=head2 eof() has the same old magic as <>
-C<eof()> would return true if no attempt to read from C<E<lt>E<gt>> had
+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<E<lt>E<gt>> files.
+own, it now opens the C<< <> >> files.
=head2 system(), backticks and pipe open now reflect exec() failure
=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
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
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
semantics in later versions of Perl.
+Many diagnostics now report the internal operation in which the warning
+was provoked, like so:
+
+ Use of uninitialized value in concatenation (.) at (eval 1) line 1.
+ Use of uninitialized value in print at (eval 1) line 1.
+
+Diagnostics that occur within eval may also report the file and line
+number where the eval is located, in addition to the eval sequence
+number and the line number within the evaluated text itself. For
+example:
+
+ Not enough arguments for scalar at (eval 4)[newlib/perl5db.pl:1411] line 2, at EOF
+
=head1 Performance enhancements
=head2 Simple sort() using { $a <=> $b } and the like are optimized
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 *
=item *
-Wrong exit code from backticks now fixed.
+Incorrect exit codes from backticks have been fixed.
=item *
-This port is still using its own builtin globbing.
+This port continues to use its own builtin globbing (not File::Glob).
=back
-=head2 OS/2
+=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.
-[TODO - Ilya Zakharevich <ilya@math.ohio-state.edu>]
+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, $pid)> can now be used to
+test whether a process exists.
+
The C<Shell> module is supported.
-Rudimentary support for building under command.com in Windows 95
+Better support for building Perl under command.com in Windows 95
has been added.
Scripts are read in binary mode by default to allow ByteLoader (and
token; if not, the DATA filehandle will be left open in binary mode.
Earlier versions always opened the DATA filehandle in text mode.
-The glob() operator is implemented via the L<File::Glob> extension,
+The glob() operator is implemented via the C<File::Glob> extension,
which supports glob syntax of the C shell. This increases the flexibility
of the glob() operator, but there may be compatibility issues for
programs that relied on the older globbing syntax. If you want to
-preserve compatibility with the older syntax, you might want to put
-a C<use File::DosGlob;> in your program. For details and compatibility
-information, see L<File::Glob>.
-
-[TODO - GSAR]
+preserve compatibility with the older syntax, you might want to run
+perl with C<-MFile::DosGlob>. For details and compatibility information,
+see L<File::Glob>.
=head1 New tests
Compatibility tests for C<sub : attrs> vs the older C<use attrs>.
+=item lib/env
+
+Tests for new environment scalar capability (e.g., C<use Env qw($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*).
=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 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
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:
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 file (more than 4GB) access Note that the O_LARGEFILE is
-automatically/transparently added to sysopen() flags if large file
-support has been configured), 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. Also SEEK_SET, SEEK_CUR, and SEEK_END
-added for one-stop shopping of the seek/sysseek constants.
+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
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
-[TODO - Brad Appleton <bradapp@enteract.com>]
+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).
+
+=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.
-
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
+=head2 perldoc
+
+C<perldoc> has been reworked to avoid possible security holes.
+It will not by default let itself be run as the superuser, but you
+may still use the B<-U> switch to try to make it drop privileges
+first.
-change#4232
-[TODO - Ilya Zakharevich <ilya@math.ohio-state.edu>]
+=head2 The Perl Debugger
+
+Many bug fixes and enhancements were added to F<perl5db.pl>, the
+Perl debugger. The help documentation was rearranged. New commands
+include C<< < ? >>, C<< > ? >>, and C<< { ? >> to list out current
+actions, C<man I<docpage>> to run your doc viewer on some perl
+docset, and support for quoted options. The help information was
+rearranged, and should be viewable once again if you're using B<less>
+as your pager. A serious security hole was plugged--you should
+immediately remove all older versions of the Perl debugger as
+installed in previous releases, all the way back to perl3, from
+your system to avoid being bitten by this.
=head1 Documentation Changes
An introduction to using the Perl Compiler suite.
+=item perldebug.pod
+
+All material unrelated to running the Perl debugger, plus all
+low-level guts-like details that risked crushing the casual user
+of the debugger, have been relocated from the old manpage to the
+next entry below.
+
+=item perldebguts.pod
+
+This new manpage contains excessively low-level material not related
+to the Perl debugger, but slightly related to debugging Perl itself.
+It also contains some arcane internal details of how the debugging
+process works that may only be of interest to developers of Perl
+debuggers.
+
=item perlfilter.pod
An introduction to writing Perl source filters.
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
=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,
+(W misc) 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
=item "our" variable %s redeclared
-(W) You seem to have already declared the same global once before in the
+(W misc) You seem to have already declared the same global once before in the
current lexical scope.
=item '!' allowed only after types %s
=item /%s/: Unrecognized escape \\%c passed through
-(W) You used a backslash-character combination which is not recognized
+(W regexp) You used a backslash-character combination which is not recognized
by Perl. This combination appears in an interpolated variable or a
C<'>-delimited regular expression. The character was understood literally.
=item /%s/: Unrecognized escape \\%c in character class passed through
-(W) You used a backslash-character combination which is not recognized
+(W regexp) You used a backslash-character combination which is not recognized
by Perl inside character classes. The character was understood literally.
=item /%s/ should probably be written as "%s"
-(W) You have used a pattern where Perl expected to find a string,
+(W syntax) You have used a pattern where Perl expected to find a string,
as in the first argument to C<join>. Perl will treat the true
or false result of matching the pattern against $_ as the string,
which is probably not what you had in mind.
=item %s() called too early to check prototype
-(W) You've called a function that has a prototype before the parser saw a
+(W prototype) You've called a function that has a prototype before the parser saw a
definition or declaration for it, and Perl could not check that the call
conforms to the prototype. You need to either add an early prototype
declaration for the subroutine in question, or move the subroutine
=item %s package attribute may clash with future reserved word: %s
-(W) A lowercase attribute name was used that had a package-specific handler.
+(W reserved) A lowercase attribute name was used that had a package-specific handler.
That name might have a meaning to Perl itself some day, even though it
doesn't yet. Perhaps you should use a mixed-case attribute name, instead.
See L<attributes>.
=item (in cleanup) %s
-(W) This prefix usually indicates that a DESTROY() method raised
+(W misc) This prefix usually indicates that a DESTROY() method raised
the indicated exception. Since destructors are usually called by
the system at arbitrary points during execution, and often a vast
number of times, the warning is issued only once for any number
=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 bareword) 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
+(W portable) The binary number you specified is larger than 2**32-1
(4294967295) and therefore non-portable between systems. See
L<perlport> for more on portability concerns.
=item Bit vector size > 32 non-portable
-(W) Using bit vector sizes larger than 32 is non-portable.
+(W portable) Using bit vector sizes larger than 32 is non-portable.
=item Buffer overflow in prime_env_iter: %s
-(W) A warning peculiar to VMS. While Perl was preparing to iterate over
+(W internal) A warning peculiar to VMS. While Perl was preparing to iterate over
%ENV, it encountered a logical name or symbol definition which was too long,
so it was truncated to the string shown.
=item Can't ignore signal CHLD, forcing to default
-(W) Perl has detected that it is being run with the SIGCHLD signal
+(W signal) 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.
+which Perl may be running (e.g., cron) is being very careless.
=item Can't modify non-lvalue subroutine call
=item Character class syntax [%s] belongs inside character classes
-(W) The character class constructs [: :], [= =], and [. .] go
+(W unsafe) The character class constructs [: :], [= =], and [. .] go
I<inside> character classes, the [] are part of the construct,
for example: /[012[:alpha:]345]/. Note that [= =] and [. .]
are not currently implemented; they are simply placeholders for
indicates a syntax error in dereferencing the constant value.
See L<perlsub/"Constant Functions"> and L<constant>.
-=item constant(%s): %%^H is not localized
+=item constant(%s): %s
-(F) When setting compile-time-lexicalized hash %^H one should set the
-corresponding bit of $^H as well.
+(F) The parser found inconsistencies either while attempting to define an
+overloaded constant, or when trying to find the character name specified
+in the C<\N{...}> escape. Perhaps you forgot to load the corresponding
+C<overload> or C<charnames> pragma? See L<charnames> and L<overload>.
-=item constant(%s): %s
+=item CORE::%s is not a keyword
-(F) Compile-time-substitutions (such as overloaded constants and
-character names) were not correctly set up.
+(F) The CORE:: namespace is reserved for Perl keywords.
=item defined(@array) is deprecated
=item Did you mean "local" instead of "our"?
-(W) Remember that "our" does not localize the declared global variable.
+(W misc) 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
=item false [] range "%s" in regexp
-(W) A character class range must start and end at a literal character, not
+(W regexp) A character class range must start and end at a literal character, not
another character class like C<\d> or C<[:alpha:]>. The "-" in your false
range is interpreted as a literal "-". Consider quoting the "-", "\-".
See L<perlre>.
=item Filehandle %s opened only for output
-(W) You tried to read from a filehandle opened only for writing. If you
+(W io) 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
+(W closed) 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 Hexadecimal number > 0xffffffff non-portable
-(W) The hexadecimal number you specified is larger than 2**32-1
+(W portable) The hexadecimal number you specified is larger than 2**32-1
(4294967295) and therefore non-portable between systems. See
L<perlport> for more on portability concerns.
=item Ill-formed CRTL environ value "%s"
-(W) A warning peculiar to VMS. Perl tried to read the CRTL's internal
+(W internal) A warning peculiar to VMS. Perl tried to read the CRTL's internal
environ array, and encountered an element without the C<=> delimiter
used to spearate keys from values. The element is ignored.
=item Ill-formed message in prime_env_iter: |%s|
-(W) A warning peculiar to VMS. Perl tried to read a logical name
+(W internal) A warning peculiar to VMS. Perl tried to read a logical name
or CLI symbol definition when preparing to iterate over %ENV, and
didn't see the expected delimiter between key and value, so the
line was ignored.
=item Illegal binary digit %s ignored
-(W) You may have tried to use a digit other than 0 or 1 in a binary number.
+(W digit) You may have tried to use a digit other than 0 or 1 in a binary number.
Interpretation of the binary number stopped before the offending digit.
=item Illegal number of bits in vec
=item Integer overflow in %s number
-(W) The hexadecimal, octal or binary number you have specified either
+(W overflow) The hexadecimal, octal or binary number you have specified either
as a literal or as an argument to hex() or oct() is too big for your
architecture, and has been converted to a floating point number. On a
32-bit architecture the largest hexadecimal, octal or binary number
=item Missing command in piped open
-(W) You used the C<open(FH, "| command")> or C<open(FH, "command |")>
+(W pipe) You used the C<open(FH, "| command")> or C<open(FH, "command |")>
construction, but the command was missing or blank.
=item Missing name in "my sub"
=item Octal number > 037777777777 non-portable
-(W) The octal number you specified is larger than 2**32-1 (4294967295)
+(W portable) The octal number you specified is larger than 2**32-1 (4294967295)
and therefore non-portable between systems. See L<perlport> for more
on portability concerns.
=item Parentheses missing around "%s" list
-(W) You said something like
+(W parenthesis) You said something like
my $foo, $bar = @_;
my ($foo, $bar) = @_;
-Remember that "my", "our" and "local" bind closer than comma.
+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
+(W y2k) You are concatenating the number 19 with another number, which
could be a potential Year 2000 problem.
+=item pragma "attrs" is deprecated, use "sub NAME : ATTRS" instead
+
+(W deprecated) You have written somehing like this:
+
+ sub doit
+ {
+ use attrs qw(locked);
+ }
+
+You should use the new declaration syntax instead.
+
+ sub doit : locked
+ {
+ ...
+
+The C<use attrs> pragma is now obsolete, and is only provided for
+backward-compatibility. See L<perlsub/"Subroutine Attributes">.
+
+
=item Premature end of script headers
See Server error.
=item Reference is already weak
-(W) You have attempted to weaken a reference that is already weak.
+(W misc) You have attempted to weaken a reference that is already weak.
Doing so has no effect.
=item setpgrp can't take arguments
=item Strange *+?{} on zero-length expression
-(W) You applied a regular expression quantifier in a place where it
+(W regexp) You applied a regular expression quantifier in a place where it
makes no sense, such as on a zero-width assertion.
Try putting the quantifier inside the assertion instead. For example,
the way to match "abc" provided that it is followed by three
=item This Perl can't set CRTL environ elements (%s=%s)
-(W) Warnings peculiar to VMS. You tried to change or delete an element
+(W internal) Warnings peculiar to VMS. You tried to change or delete an element
of the CRTL's internal environ array, but your copy of Perl wasn't
built with a CRTL that contained the setenv() function. You'll need to
rebuild Perl with a CRTL that does, or redefine F<PERL_ENV_TABLES> (see
L<perlvms>) so that the environ array isn't the target of the change to
%ENV which produced the warning.
+=item Too late to run %s block
+
+(W void) A CHECK or INIT block is being defined during run time proper,
+when the opportunity to run them has already passed. Perhaps you are
+loading a file with C<require> or C<do> when you should be using
+C<use> instead. Or perhaps you should put the C<require> or C<do>
+inside a BEGIN block.
+
=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
=item Unrecognized escape \\%c passed through
-(W) You used a backslash-character combination which is not recognized
+(W misc) You used a backslash-character combination which is not recognized
by Perl. The character was understood literally.
=item Unterminated attribute parameter in attribute list
=item Value of CLI symbol "%s" too long
-(W) A warning peculiar to VMS. Perl tried to read the value of an %ENV
+(W misc) A warning peculiar to VMS. Perl tried to read the value of an %ENV
element from a CLI symbol table, and found a resultant string longer
than 1024 characters. The return value has been truncated to 1024
characters.
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.
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