=head1 NAME
perl589delta - what is new for perl v5.8.9
=head1 DESCRIPTION
This document describes differences between the 5.8.8 release and
the 5.8.9 release.
=head1 Notice
The 5.8.9 release will be the last significant release of the 5.8.x
series. Any future releases of 5.8.x will likely only be to deal with
security issues, and platform build failures. Hence you should look to
migrating to 5.10.x, if you have not started already.
See L for more information.
=head1 Incompatible Changes
A particular construction in the source code of extensions written in C++
may need changing. See L for more details. All
extensions written in C, most written in C++, and all existing compiled
extensions are unaffected. This was necessary to improve C++ support.
Other than this, there are no changes intentionally incompatible with 5.8.8.
If any exist, they are bugs and reports are welcome.
=head1 Core Enhancements
=head2 Unicode Character Database 5.1.0.
The copy of the Unicode Character Database included in Perl 5.8 has
been updated to 5.1.0 from 4.1.0. See
L for the
notable changes.
=head2 stat and -X on directory handles
It is now possible to call C and the C<-X> filestat operators on
directory handles. As both directory and file handles are barewords, there
can be ambiguities over which was intended. In these situations the file
handle semantics are preferred. Both also treat C<*FILE{IO}> filehandles
like C<*FILE> filehandles.
=head2 Source filters in @INC
It's possible to enhance the mechanism of subroutine hooks in @INC by
adding a source filter on top of the filehandle opened and returned by the
hook. This feature was planned a long time ago, but wasn't quite working
until now. See L for details. (Nicholas Clark)
=head2 Exceptions in constant folding
The constant folding routine is now wrapped in an exception handler, and
if folding throws an exception (such as attempting to evaluate 0/0), perl
now retains the current optree, rather than aborting the whole program.
Without this change, programs would not compile if they had expressions that
happened to generate exceptions, even though those expressions were in code
that could never be reached at runtime. (Nicholas Clark, Dave Mitchell)
=head2 C
You can now use C followed by a version number to specify that you
want to use a version of perl older than the specified one.
=head2 Improved internal UTF-8 caching code
The code that caches calculated UTF-8 byte offsets for character offsets for
a string has been re-written. Several bugs have been located and eliminated,
and the code now makes better use of the information it has, so should be
faster. In particular, it doesn't scan to the end of a string before
calculating an offset within the string, which should speed up some operations
on long strings. It is now possible to disable the caching code at run time,
to verify that it is not the cause of suspected problems.
=head2 Runtime relocatable installations
There is now F support for creating a perl tree that is relocatable
at run time. see L.
=head2 New internal variables
=over 4
=item C<${^CHILD_ERROR_NATIVE}>
This variable gives the native status returned by the last pipe close,
backtick command, successful call to C or C, or from the
C operator. See L for details. (Contributed by Gisle Aas.)
=item C<${^UTF8CACHE}>
This variable controls the state of the internal UTF-8 offset caching code.
1 for on (the default), 0 for off, -1 to debug the caching code by checking
all its results against linear scans, and panicing on any discrepancy.
=back
=head2 C is now overridable
The built-in function C is now overridable. Overriding it permits
also to override its operator counterpart, C (also known as C<``>).
=head2 simple exception handling macros
Perl 5.8.9 (and 5.10.0 onwards) now provides a couple of macros to do very
basic exception handling in XS modules. You can use these macros if you call
code that may C, but you need to do some cleanup before giving control
back to Perl. See L for more details.
=head2 -D option enhancements
=over
=item *
C<-Dq> suppresses the I message when running under C<-D>
=item *
C<-Dl> logs runops loop entry and exit, and jump level popping.
=item *
C<-Dv> displays the process id as part of the trace output.
=back
=head2 XS-assisted SWASHGET
Some pure-perl code that the regexp engine was using to retrieve Unicode
properties and transliteration mappings has been reimplemented in XS
for faster execution.
(SADAHIRO Tomoyuki)
=head2 Constant subroutines
The interpreter internals now support a far more memory efficient form of
inlineable constants. Storing a reference to a constant value in a symbol
table is equivalent to a full typeglob referencing a constant subroutine,
but using about 400 bytes less memory. This proxy constant subroutine is
automatically upgraded to a real typeglob with subroutine if necessary.
The approach taken is analogous to the existing space optimisation for
subroutine stub declarations, which are stored as plain scalars in place
of the full typeglob.
However, to aid backwards compatibility of existing code, which (wrongly)
does not expect anything other than typeglobs in symbol tables, nothing in
core uses this feature, other than the regression tests.
Stubs for prototyped subroutines have been stored in symbol tables as plain
strings, and stubs for unprototyped subroutines as the number -1, since 5.005,
so code which assumes that the core only places typeglobs in symbol tables
has been making incorrect assumptions for over 10 years.
=head1 New Platforms
Compile support added for:
=over
=item *
DragonFlyBSD
=item *
MidnightBSD
=item *
MirOS BSD
=item *
RISC OS
=item *
Cray XT4/Catamount
=back
=head1 Modules and Pragmata
=head2 New Modules
=over
=item *
C is a simple framework to create modules that accept
pluggable sub-modules. The bundled version is 3.8
=item *
C is a hash of hashes that is keyed on perl version as
indicated in C<$]>. The bundled version is 2.17
=item *
C now available in core on Microsoft Windows. The bundled
version is 0.1001_01
=item *
C finds all the packages defined by a single file. It is
part of the C distribution. The bundled version is 0.3
=back
=head2 Updated Modules
=over
=item *
C upgraded to version 0.09
=item *
C upgraded to version 5.67
=item *
C upgraded to 1.06
=item *
C upgraded to version 1.06
=item *
C upgraded from 1.09_01 to 1.19
=over
=item *
provides new pad related abstraction macros C,
C, C,
C, which hides the difference in storage in
5.10.0 and later.
=item *
provides C, which exposes C
=item *
provides C, which on pre-5.10 perls always returns true.
=item *
New type C added with methods C, C and C
=item *
The C flag is now set correctly when a proxy
constant subroutine is imported.
=item *
bugs fixed in the handling of Cs.
=item *
C returns now C, not C.
C and C return now C on an XSUB,
C and C return 0 on a non-XSUB.
=back
=item *
C upgraded to 1.05
=item *
C upgraded to 0.76
=over
=item *
new option C<-src> causes the rendering of each statement (starting with
the nextstate OP) to be preceded by the first line of source code that
generates it.
=item *
new option C<-stash="somepackage">, Cs "somepackage", and then renders
each function defined in its namespace.
=item *
now has documentation of detailed hint symbols.
=back
=item *
C upgraded to version 1.05
=item *
C upgraded to version 0.87
=over 4
=item *
properly deparse C.
=item *
now handles C<''->()>, C<::()>, C, I correctly [RT #43010].
All bugs in parsing these kinds of syntax are now fixed:
perl -MO=Deparse -e '"my %h = "->()'
perl -MO=Deparse -e '::->()'
perl -MO=Deparse -e 'sub :: {}'
perl -MO=Deparse -e 'package a; sub a::b::c {}'
perl -MO=Deparse -e 'sub the::main::road {}'
=item *
does B deparse C<$^H{v_string}>, which is automatically set by the
internals.
=back
=item *
C upgraded to version 1.11
=item *
C upgraded to version 1.05
=item *
C upgraded to version 2.13
=over 4
=item *
loading a module via base.pm would mask a global C<$SIG{__DIE__}> in that
module.
=item *
push all classes at once in C<@ISA>
=back
=item *
C upgraded to version 1.10
=item *
C upgraded to 0.23
=item *
C upgraded to 0.23
=item *
C upgraded to 0.23
=item *
C upgraded to 0.04
=item *
C upgraded to version 1.10
The argument backtrace code now shows C as C,
instead of a string I<"undef">.
=item *
C upgraded to version 3.42
=item *
C upgraded to 1.06
=item *
C upgraded to version 1.17
=item *
C upgraded to version 1.9301
=item *
C upgraded to version 3.29 with some platform specific
improvements (including for VMS).
=item *
C upgraded to version 2.121_17
=over
=item *
Fixes hash iterator current position with the pure Perl version [RT #40668]
=item *
Performance enhancements, which will be most evident on platforms where
repeated calls to C's C are slow, such as Win32.
=back
=item *
C upgraded to version 1.817
=item *
C upgraded to version 0.02
=item *
C upgraded to version 20080331.00
=item *
C upgraded to version 1.04
=item *
C upgraded to version 3.14
=item *
C upgraded to version 1.16
=item *
C upgraded to version 1.15
=item *
C upgraded to version 2.37
=item *
C upgraded to version 1.02
=over
=item *
now localises C<$.>, C<$@>, C<$!>, C<$^E>, and C<$?> before closing the
directory handle to suppress leaking any side effects of warnings about it
already being closed.
=back
=item *
C upgraded to version 1.09
C can now dynamically load a loadable object from a file with a
non-default file extension.
=item *
C upgraded to version 2.26
C includes a fix for encoding "646" on Solaris (better known as
ASCII).
=item *
C upgraded to version 1.03
=item *
C upgraded to version 1.10
=item *
C upgraded to version 5.63
=item *
C upgraded to version 1.15
=item *
C upgraded to version 0.21
=item *
C upgraded to version 1.28
=item *
C upgraded to version 1.50_01
=item *
C upgraded to version 1.43
=item *
C upgraded to version 6.48
=over
=item *
support for C and C
configuration.
=back
=item *
C upgraded to version 1.55
=item *
C upgraded to version 2.19
=item *
C upgraded to version 1.06
=over
=item *
allows built-ins in C to be made fatal.
=back
=item *
C upgraded to version 1.06
=item *
C upgraded to version 2.12
=item *
C upgraded to version 2.77
=item *
C upgraded to version 1.07
=item *
C upgraded to 1.1005
=item *
C upgraded to 2.13
=over 4
=item *
now uses 3-arg open.
=back
=item *
C upgraded to 1.01
=item *
C upgraded to version 1.13
=item *
C upgraded to version 1.06
=over
=item *
fixes spurious results with brackets inside braces.
=back
=item *
C upgraded to version 2.07_02
=item *
C upgraded to version 3.29
=over 4
=item *
improved handling of bad arguments.
=item *
some platform specific improvements (including for VMS and Cygwin), with
an optimisation on C when handling both relative arguments.
=back
=item *
C upgraded to version 1.01
=item *
C upgraded to version 0.20
=item *
C upgraded to version 1.02
=item *
C upgraded to version 1.07
=item *
C upgraded to version 0.83
=item *
C upgraded to version 1.49
=item *
C upgraded to version 1.09
=item *
C upgraded to version 2.37
=item *
C upgraded to version 1.06
=item *
C upgraded to version 0.06
=item *
C upgraded to version 0.05
=item *
C upgraded to version 1.23
Reduced number of calls to C in C
=item *
C upgraded to version 1.03
=item *
C upgraded to version 1.03
=item *
C upgraded to version 2.00
=item *
C upgraded to version 0.61
=over
=item *
avoid warning about loading F<.par> files.
=back
=item *
C upgraded to version 1.22
=item *
C upgraded to 1.19
=item *
C upgraded to 1.13
=item *
C upgraded to version 1.60
=item *
C upgraded to version 1.89
=item *
C upgraded to version 0.22
=over 4
=item *
implements new C method.
=back
=item *
C upgraded to version 1.54.
=item *
C upgraded to version 1.18.
=item *
C upgraded to version 1.07
=over
=item *
improve F handling for systems using GDBM compatibility headers.
=back
=item *
C upgraded to version 2.35
=item *
C upgraded to version 0.61
=over
=item *
fix several bugs with C when working with C, C block, and
within overloaded stringification.
=back
=item *
C upgraded to 1.07
=item *
C upgraded to 1.06
=item *
C upgraded to 1.02
=item *
C upgraded to version 0.11
=item *
C upgraded to version 0.06
=over 4
=item *
[RT #40267] C doesn't respect readonly-ness.
=back
=item *
C upgraded to version 0.05
=item *
C upgraded to version 1.09
=item *
C upgraded to version 1.35
=item *
C upgraded to version 1.35
=item *
C upgraded to version 1.15
=over
=item *
C constants that duplicate those in C are now imported from
C and re-exported, rather than being duplicated by C
=item *
C can remove empty directories.
=item *
C safer to call multiple times.
=item *
C added, which provides access to POSIX realtime signal
functionality on systems that support it.
=back
=item *
C upgraded to version 0.06_01
=item *
C upgraded to version 2.16
=item *
C upgraded to 1.19
=item *
C upgraded to version 1.06
=item *
C upgraded to version 1.17
=item *
C upgraded to version 0.72
=item *
C upgraded to version 1.04
=item *
C upgraded to version 1.81
=over
=item *
this fixes an optimistic use of C
=back
=item *
C upgraded to 2.19
=item *
C upgraded to version 2.13
=item *
C upgraded to version 0.27
=item *
C upgraded to version 1.12
=item *
C upgraded to version 1.12
=item *
C upgraded to version 1.03
=item *
C upgraded to version 0.80
=item *
C upgraded version to 2.64
=over
=item *
this makes it able to handle newlines.
=back
=item *
C upgraded to version 0.80
=item *
C upgraded to version 0.80
=item *
C upgraded to version 1.98
=item *
C upgraded to version 3.27
=item *
C upgraded to version 3.03
=item *
C upgraded to version 2007.1117
=item *
C upgraded to version 2006.1117
=item *
C upgraded to version 2.01
=item *
C upgraded to version 2.09
=item *
C upgraded to version 2.11
=over
=item *
added capability to add complex structures (e.g., hash of hashes) to queues.
=item *
added capability to dequeue multiple items at once.
=item *
added new methods to inspect and manipulate queues: C, C and
C
=back
=item *
C upgraded to version 4.2
=item *
C upgraded to version 1.03
=item *
C upgraded to version 1.1
=over
=item *
C now correctly caches its results.
=back
=item *
C upgraded to version 1.38
=item *
C upgraded to version 1.01
=item *
C upgraded to version 4.2
=item *
C upgraded to version 1.03
=item *
C upgraded to version 1.1901
=item *
C upgraded to version 1.9715 with various build improvements
(including VMS) and minor platform-specific bug fixes (including
for HP-UX 11 ia64).
=item *
C upgraded to 1.71
=over
=item *
new thread state information methods: C, C
and C. C method enhanced to return running or joinable
threads.
=item *
new thread signal method: C
=item *
added capability to specify thread stack size.
=item *
added capability to control thread exiting behavior. Added a new C
method.
=back
=item *
C upgraded to version 1.27
=over
=item *
smaller and faster implementation that eliminates one internal structure and
the consequent level of indirection.
=item *
user locks are now stored in a safer manner.
=item *
new function C creates a copy of an object leaving
shared elements as-is and deep-cloning non-shared elements.
=item *
added new C method.
=back
=item *
C upgraded to version 1.02
=item *
C upgraded to version 0.25
=item *
C upgraded to version 1.05_01
=item *
C upgraded to version 0.38
=over 4
=item *
added new function C which returns the regular Windows
process identifier of the current process, even when called from within a fork.
=back
=item *
C upgraded to version 0.10
=item *
C and C are for internal use only and hence
no longer installed. Many more tests have been added to C.
=back
=head1 Utility Changes
=head2 debugger upgraded to version 1.31
=over 4
=item *
Andreas KEnig contributed two functions to save and load the debugger
history.
=item *
C no longer emits warnings under the debugger.
=item *
The debugger should now correctly find tty the device on OS X 10.5 and VMS
when the program Cs.
=item *
LVALUE subs now work inside the debugger.
=back
=head2 F
Perl 5.8.9 adds a new utility F, which is a variant of F,
but for sending non-bug-reports to the authors and maintainers of Perl.
Getting nothing but bug reports can become a bit demoralising - we'll see if
this changes things.
=head2 F
F now checks if you're reporting about a non-core module and suggests
you report it to the CPAN author instead.
=head2 F
=over
=item *
won't define an empty string as a constant [RT #25366]
=item *
has examples for C
=back
=head2 F
=over 4
=item *
now attempts to deal sensibly with the difference in path implications
between C<""> and C<< EE >> quoting in C<#include> statements.
=item *
now generates correct correct code for C<#if defined A || defined B>
[RT #39130]
=back
=head1 New Documentation
As usual, the documentation received its share of corrections, clarifications
and other nitfixes. More C<< X<...> >> tags were added for indexing.
L is a tutorial written by Juerd Waalboer on Unicode-related
terminology and how to correctly handle Unicode in Perl scripts.
L is updated in section user defined properties.
L has been updated in the example of detecting data that is not
valid in particular encoding.
L provides an overview of the Perl Community along with further
resources.
L documents the pseudo-namespace for Perl's core routines.
=head1 Changes to Existing Documentation
L adds I and I.
L has been updated and added resources on smoke testing.
The Perl FAQs (F..F) have been updated.
L is updated with better details on C<\w>, C<\d>, and C<\s>.
L is updated with information on how to call the debugger.
L documentation updated with I on the
argument to C and C and also several terminology updates on
warnings.
L documents the limitation of C