PERL589DELTA(1) Perl Programmers Reference Guide PERL589DELTA(1)
NAME
perl589delta - what is new for perl v5.8.9
DESCRIPTION
This document describes differences between the 5.8.8 release and the
5.8.9 release.
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 "Known
Problems" for more information.
Incompatible Changes
A particular construction in the source code of extensions written in
C++ may need changing. See "Changed Internals" 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.
Core Enhancements
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
<http://www.unicode.org/versions/Unicode5.1.0/#NotableChanges>; for the
notable changes.
stat and -X on directory handles
It is now possible to call "stat" and the "-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 *FILE{IO}
filehandles like *FILE filehandles.
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 "require" in perlfunc for details. (Nicholas
Clark)
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)
"no VERSION"
You can now use "no" followed by a version number to specify that you
want to use a version of perl older than the specified one.
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.
Runtime relocatable installations
There is now Configure support for creating a perl tree that is
relocatable at run time. see "Relocatable installations".
New internal variables
"${^CHILD_ERROR_NATIVE}"
This variable gives the native status returned by the last pipe
close, backtick command, successful call to "wait" or "waitpid", or
from the "system" operator. See perlvar for details. (Contributed
by Gisle Aas.)
"${^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
panicking on any discrepancy.
"readpipe" is now overridable
The built-in function "readpipe" is now overridable. Overriding it
permits also to override its operator counterpart, "qx//" (also known
as "``").
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 "croak", but you need to do some cleanup
before giving control back to Perl. See "Exception Handling" in
perlguts for more details.
-D option enhancements
o "-Dq" suppresses the EXECUTING... message when running under "-D"
o "-Dl" logs runops loop entry and exit, and jump level popping.
o "-Dv" displays the process id as part of the trace output.
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)
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.
New Platforms
Compile support added for:
o DragonFlyBSD
o MidnightBSD
o MirOS BSD
o RISC OS
o Cray XT4/Catamount
Modules and Pragmata
New Modules
o "Module::Pluggable" is a simple framework to create modules that
accept pluggable sub-modules. The bundled version is 3.8
o "Module::CoreList" is a hash of hashes that is keyed on perl
version as indicated in $]. The bundled version is 2.17
o "Win32API::File" now available in core on Microsoft Windows. The
bundled version is 0.1001_01
o "Devel::InnerPackage" finds all the packages defined by a single
file. It is part of the "Module::Pluggable" distribution. The
bundled version is 0.3
Updated Modules
o "attributes" upgraded to version 0.09
o "AutoLoader" upgraded to version 5.67
o "AutoSplit" upgraded to 1.06
o "autouse" upgraded to version 1.06
o "B" upgraded from 1.09_01 to 1.19
o provides new pad related abstraction macros
"B::NV::COP_SEQ_RANGE_LOW", "B::NV::COP_SEQ_RANGE_HIGH",
"B::NV::PARENT_PAD_INDEX", "B::NV::PARENT_FAKELEX_FLAGS", which
hides the difference in storage in 5.10.0 and later.
o provides "B::sub_generation", which exposes "PL_sub_generation"
o provides "B::GV::isGV_with_GP", which on pre-5.10 perls always
returns true.
o New type "B::HE" added with methods "VAL", "HASH" and
"SVKEY_force"
o The "B::GVf_IMPORTED_CV" flag is now set correctly when a proxy
constant subroutine is imported.
o bugs fixed in the handling of "PMOP"s.
o "B::BM::PREVIOUS" returns now "U32", not "U16". "B::CV::START"
and "B:CV::ROOT" return now "NULL" on an XSUB, "B::CV::XSUB"
and "B::CV::XSUBANY" return 0 on a non-XSUB.
o "B::C" upgraded to 1.05
o "B::Concise" upgraded to 0.76
o new option "-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.
o new option "-stash="somepackage"", "require"s "somepackage",
and then renders each function defined in its namespace.
o now has documentation of detailed hint symbols.
o "B::Debug" upgraded to version 1.05
o "B::Deparse" upgraded to version 0.87
o properly deparse "print readpipe $x, $y".
o now handles "''-"()>, "::()", "sub :: {}", etc. 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 {}'
o does not deparse $^H{v_string}, which is automatically set by
the internals.
o "B::Lint" upgraded to version 1.11
o "B::Terse" upgraded to version 1.05
o "base" upgraded to version 2.13
o loading a module via base.pm would mask a global $SIG{__DIE__}
in that module.
o push all classes at once in @ISA
o "Benchmark" upgraded to version 1.10
o "bigint" upgraded to 0.23
o "bignum" upgraded to 0.23
o "bigrat" upgraded to 0.23
o "blib" upgraded to 0.04
o "Carp" upgraded to version 1.10
The argument backtrace code now shows "undef" as "undef", instead
of a string "undef".
o "CGI" upgraded to version 3.42
o "charnames" upgraded to 1.06
o "constant" upgraded to version 1.17
o "CPAN" upgraded to version 1.9301
o "Cwd" upgraded to version 3.29 with some platform specific
improvements (including for VMS).
o "Data::Dumper" upgraded to version 2.121_17
o Fixes hash iterator current position with the pure Perl version
[RT #40668]
o Performance enhancements, which will be most evident on
platforms where repeated calls to C's "realloc()" are slow,
such as Win32.
o "DB_File" upgraded to version 1.817
o "DB_Filter" upgraded to version 0.02
o "Devel::DProf" upgraded to version 20080331.00
o "Devel::Peek" upgraded to version 1.04
o "Devel::PPPort" upgraded to version 3.14
o "diagnostics" upgraded to version 1.16
o "Digest" upgraded to version 1.15
o "Digest::MD5" upgraded to version 2.37
o "DirHandle" upgraded to version 1.02
o now localises $., $@, $!, $^E, and $? before closing the
directory handle to suppress leaking any side effects of
warnings about it already being closed.
o "DynaLoader" upgraded to version 1.09
"DynaLoader" can now dynamically load a loadable object from a file
with a non-default file extension.
o "Encode" upgraded to version 2.26
"Encode::Alias" includes a fix for encoding "646" on Solaris
(better known as ASCII).
o "English" upgraded to version 1.03
o "Errno" upgraded to version 1.10
o "Exporter" upgraded to version 5.63
o "ExtUtils::Command" upgraded to version 1.15
o "ExtUtils::Constant" upgraded to version 0.21
o "ExtUtils::Embed" upgraded to version 1.28
o "ExtUtils::Install" upgraded to version 1.50_01
o "ExtUtils::Installed" upgraded to version 1.43
o "ExtUtils::MakeMaker" upgraded to version 6.48
o support for "INSTALLSITESCRIPT" and "INSTALLVENDORSCRIPT"
configuration.
o "ExtUtils::Manifest" upgraded to version 1.55
o "ExtUtils::ParseXS" upgraded to version 2.19
o "Fatal" upgraded to version 1.06
o allows built-ins in "CORE::GLOBAL" to be made fatal.
o "Fcntl" upgraded to version 1.06
o "fields" upgraded to version 2.12
o "File::Basename" upgraded to version 2.77
o "FileCache" upgraded to version 1.07
o "File::Compare" upgraded to 1.1005
o "File::Copy" upgraded to 2.13
o now uses 3-arg open.
o "File::DosGlob" upgraded to 1.01
o "File::Find" upgraded to version 1.13
o "File::Glob" upgraded to version 1.06
o fixes spurious results with brackets inside braces.
o "File::Path" upgraded to version 2.07_02
o "File::Spec" upgraded to version 3.29
o improved handling of bad arguments.
o some platform specific improvements (including for VMS and
Cygwin), with an optimisation on "abs2rel" when handling both
relative arguments.
o "File::stat" upgraded to version 1.01
o "File::Temp" upgraded to version 0.20
o "filetest" upgraded to version 1.02
o "Filter::Util::Call" upgraded to version 1.07
o "Filter::Simple" upgraded to version 0.83
o "FindBin" upgraded to version 1.49
o "GDBM_File" upgraded to version 1.09
o "Getopt::Long" upgraded to version 2.37
o "Getopt::Std" upgraded to version 1.06
o "Hash::Util" upgraded to version 0.06
o "if" upgraded to version 0.05
o "IO" upgraded to version 1.23
Reduced number of calls to "getpeername" in "IO::Socket"
o "IPC::Open" upgraded to version 1.03
o "IPC::Open3" upgraded to version 1.03
o "IPC::SysV" upgraded to version 2.00
o "lib" upgraded to version 0.61
o avoid warning about loading .par files.
o "libnet" upgraded to version 1.22
o "List::Util" upgraded to 1.19
o "Locale::Maketext" upgraded to 1.13
o "Math::BigFloat" upgraded to version 1.60
o "Math::BigInt" upgraded to version 1.89
o "Math::BigRat" upgraded to version 0.22
o implements new "as_float" method.
o "Math::Complex" upgraded to version 1.54.
o "Math::Trig" upgraded to version 1.18.
o "NDBM_File" upgraded to version 1.07
o improve g++ handling for systems using GDBM compatibility
headers.
o "Net::Ping" upgraded to version 2.35
o "NEXT" upgraded to version 0.61
o fix several bugs with "NEXT" when working with "AUTOLOAD",
"eval" block, and within overloaded stringification.
o "ODBM_File" upgraded to 1.07
o "open" upgraded to 1.06
o "ops" upgraded to 1.02
o "PerlIO::encoding" upgraded to version 0.11
o "PerlIO::scalar" upgraded to version 0.06
o [RT #40267] "PerlIO::scalar" doesn't respect readonly-ness.
o "PerlIO::via" upgraded to version 0.05
o "Pod::Html" upgraded to version 1.09
o "Pod::Parser" upgraded to version 1.35
o "Pod::Usage" upgraded to version 1.35
o "POSIX" upgraded to version 1.15
o "POSIX" constants that duplicate those in "Fcntl" are now
imported from "Fcntl" and re-exported, rather than being
duplicated by "POSIX"
o "POSIX::remove" can remove empty directories.
o "POSIX::setlocale" safer to call multiple times.
o "POSIX::SigRt" added, which provides access to POSIX realtime
signal functionality on systems that support it.
o "re" upgraded to version 0.06_01
o "Safe" upgraded to version 2.16
o "Scalar::Util" upgraded to 1.19
o "SDBM_File" upgraded to version 1.06
o "SelfLoader" upgraded to version 1.17
o "Shell" upgraded to version 0.72
o "sigtrap" upgraded to version 1.04
o "Socket" upgraded to version 1.81
o this fixes an optimistic use of "gethostbyname"
o "Storable" upgraded to 2.19
o "Switch" upgraded to version 2.13
o "Sys::Syslog" upgraded to version 0.27
o "Term::ANSIColor" upgraded to version 1.12
o "Term::Cap" upgraded to version 1.12
o "Term::ReadLine" upgraded to version 1.03
o "Test::Builder" upgraded to version 0.80
o "Test::Harness" upgraded version to 2.64
o this makes it able to handle newlines.
o "Test::More" upgraded to version 0.80
o "Test::Simple" upgraded to version 0.80
o "Text::Balanced" upgraded to version 1.98
o "Text::ParseWords" upgraded to version 3.27
o "Text::Soundex" upgraded to version 3.03
o "Text::Tabs" upgraded to version 2007.1117
o "Text::Wrap" upgraded to version 2006.1117
o "Thread" upgraded to version 2.01
o "Thread::Semaphore" upgraded to version 2.09
o "Thread::Queue" upgraded to version 2.11
o added capability to add complex structures (e.g., hash of
hashes) to queues.
o added capability to dequeue multiple items at once.
o added new methods to inspect and manipulate queues: "peek",
"insert" and "extract"
o "Tie::Handle" upgraded to version 4.2
o "Tie::Hash" upgraded to version 1.03
o "Tie::Memoize" upgraded to version 1.1
o "Tie::Memoize::EXISTS" now correctly caches its results.
o "Tie::RefHash" upgraded to version 1.38
o "Tie::Scalar" upgraded to version 1.01
o "Tie::StdHandle" upgraded to version 4.2
o "Time::gmtime" upgraded to version 1.03
o "Time::Local" upgraded to version 1.1901
o "Time::HiRes" upgraded to version 1.9715 with various build
improvements (including VMS) and minor platform-specific bug fixes
(including for HP-UX 11 ia64).
o "threads" upgraded to 1.71
o new thread state information methods: "is_running",
"is_detached" and "is_joinable". "list" method enhanced to
return running or joinable threads.
o new thread signal method: "kill"
o added capability to specify thread stack size.
o added capability to control thread exiting behavior. Added a
new "exit" method.
o "threads::shared" upgraded to version 1.27
o smaller and faster implementation that eliminates one internal
structure and the consequent level of indirection.
o user locks are now stored in a safer manner.
o new function "shared_clone" creates a copy of an object leaving
shared elements as-is and deep-cloning non-shared elements.
o added new "is_shared" method.
o "Unicode::Normalize" upgraded to version 1.02
o "Unicode::UCD" upgraded to version 0.25
o "warnings" upgraded to version 1.05_01
o "Win32" upgraded to version 0.38
o added new function "GetCurrentProcessId" which returns the
regular Windows process identifier of the current process, even
when called from within a fork.
o "XSLoader" upgraded to version 0.10
o "XS::APItest" and "XS::Typemap" are for internal use only and hence
no longer installed. Many more tests have been added to
"XS::APItest".
Utility Changes
debugger upgraded to version 1.31
o Andreas Koenig contributed two functions to save and load the
debugger history.
o "NEXT::AUTOLOAD" no longer emits warnings under the debugger.
o The debugger should now correctly find tty the device on OS X 10.5
and VMS when the program "fork"s.
o LVALUE subs now work inside the debugger.
perlthanks
Perl 5.8.9 adds a new utility perlthanks, which is a variant of
perlbug, 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.
perlbug
perlbug now checks if you're reporting about a non-core module and
suggests you report it to the CPAN author instead.
h2xs
o won't define an empty string as a constant [RT #25366]
o has examples for "h2xs -X"
h2ph
o now attempts to deal sensibly with the difference in path
implications between "" and "<>" quoting in "#include" statements.
o now generates correct code for "#if defined A || defined B" [RT
#39130]
New Documentation
As usual, the documentation received its share of corrections,
clarifications and other nitfixes. More "" tags were added for
indexing.
perlunitut is a tutorial written by Juerd Waalboer on Unicode-related
terminology and how to correctly handle Unicode in Perl scripts.
perlunicode is updated in section user defined properties.
perluniintro has been updated in the example of detecting data that is
not valid in particular encoding.
perlcommunity provides an overview of the Perl Community along with
further resources.
CORE documents the pseudo-namespace for Perl's core routines.
Changes to Existing Documentation
perlglossary adds deprecated modules and features and to be dropped
modules.
perlhack has been updated and added resources on smoke testing.
The Perl FAQs (perlfaq1..perlfaq9) have been updated.
perlcheat is updated with better details on "\w", "\d", and "\s".
perldebug is updated with information on how to call the debugger.
perldiag documentation updated with subroutine with an ampersand on the
argument to "exists" and "delete" and also several terminology updates
on warnings.
perlfork documents the limitation of "exec" inside pseudo-processes.
perlfunc:
o Documentation is fixed in section "caller" and "pop".
o Function "alarm" now mentions "Time::HiRes::ualarm" in preference
to "select".
o Regarding precedence in "-X", filetest operators are the same as
unary operators, but not regarding parsing and parentheses (spotted
by Eirik Berg Hanssen).
o "reverse" function documentation received scalar context examples.
perllocale documentation is adjusted for number localization and
"POSIX::setlocale" to fix Debian bug #379463.
perlmodlib is updated with "CPAN::API::HOWTO" and
"Sys::Syslog::win32::Win32"
perlre documentation updated to reflect the differences between
"[[:xxxxx:]]" and "\p{IsXxxxx}" matches. Also added section on "/g" and
"/c" modifiers.
perlreguts describe the internals of the regular expressions engine. It
has been contributed by Yves Orton.
perlrebackslash describes all perl regular expression backslash and
escape sequences.
perlrecharclass describes the syntax and use of character classes in
Perl Regular Expressions.
perlrun is updated to clarify on the hash seed PERL_HASH_SEED. Also
more information in options "-x" and "-u".
perlsub example is updated to use a lexical variable for "opendir"
syntax.
perlvar fixes confusion about real GID $( and effective GID $).
Perl thread tutorial example is fixed in section "Queues: Passing Data
Around" in perlthrtut and perlthrtut.
perlhack documentation extensively improved by Jarkko Hietaniemi and
others.
perltoot provides information on modifying @UNIVERSAL::ISA.
perlport documentation extended to include different "kill(-9, ...)"
semantics on Windows. It also clearly states "dump" is not supported on
Win32 and cygwin.
INSTALL has been updated and modernised.
Performance Enhancements
o The default since perl 5.000 has been for perl to create an empty
scalar with every new typeglob. The increased use of lexical
variables means that most are now unused. Thanks to Nicholas
Clark's efforts, Perl can now be compiled with
"-DPERL_DONT_CREATE_GVSV" to avoid creating these empty scalars.
This will significantly decrease the number of scalars allocated
for all configurations, and the number of scalars that need to be
copied for ithread creation. Whilst this option is binary
compatible with existing perl installations, it does change a long-
standing assumption about the internals, hence it is not enabled by
default, as some third party code may rely on the old behaviour.
We would recommend testing with this configuration on new
deployments of perl, particularly for multi-threaded servers, to
see whether all third party code is compatible with it, as this
configuration may give useful performance improvements. For
existing installations we would not recommend changing to this
configuration unless thorough testing is performed before
deployment.
o "diagnostics" no longer uses $&, which results in large speedups
for regexp matching in all code using it.
o Regular expressions classes of a single character are now treated
the same as if the character had been used as a literal, meaning
that code that uses char-classes as an escaping mechanism will see
a speedup. (Yves Orton)
o Creating anonymous array and hash references (ie. "[]" and "{}")
now incurs no more overhead than creating an anonymous list or
hash. Nicholas Clark provided changes with a saving of two ops and
one stack push, which was measured as a slightly better than 5%
improvement for these operations.
o Many calls to "strlen()" have been eliminated, either because the
length was already known, or by adopting or enhancing APIs that
pass lengths. This has been aided by the adoption of a
"my_sprintf()" wrapper, which returns the correct C89 value - the
length of the formatted string. Previously we could not rely on the
return value of "sprintf()", because on some ancient but extant
platforms it still returns "char *".
o "index" is now faster if the search string is stored in UTF-8 but
only contains characters in the Latin-1 range.
o The Unicode swatch cache inside the regexp engine is now used. (the
lookup had a key mismatch, present since the initial
implementation). [RT #42839]
Installation and Configuration Improvements
Relocatable installations
There is now Configure support for creating a relocatable perl tree. If
you Configure with "-Duserelocatableinc", then the paths in @INC (and
everything else in %Config) can be optionally located via the path of
the perl executable.
At start time, if any paths in @INC or "Config" that Configure marked
as relocatable (by starting them with ".../"), then they are prefixed
the directory of $^X. This allows the relocation can be configured on a
per-directory basis, although the default with "-Duserelocatableinc" is
that everything is relocated. The initial install is done to the
original configured prefix.
Configuration improvements
Configure is now better at removing temporary files. Tom Callaway (from
RedHat) also contributed patches that complete the set of flags passed
to the compiler and the linker, in particular that "-fPIC" is now
enabled on Linux. It will also croak when your /dev/null isn't a
device.
A new configuration variable "d_pseudofork" has been to Configure, and
is available as $Config{d_pseudofork} in the "Config" module. This
distinguishes real "fork" support from the pseudofork emulation used on
Windows platforms.
Config.pod and config.sh are now placed correctly for cross-
compilation.
$Config{useshrplib} is now 'true' rather than 'yes' when using a shared
perl library.
Compilation improvements
Parallel makes should work properly now, although there may still be
problems if "make test" is instructed to run in parallel.
Many compilation warnings have been cleaned up. A very stubborn
compiler warning in "S_emulate_eaccess()" was killed after six
attempts. g++ support has been tuned, especially for FreeBSD.
mkppport has been integrated, and all ppport.h files in the core will
now be autogenerated at build time (and removed during cleanup).
Installation improvements.
installman now works with "-Duserelocatableinc" and "DESTDIR".
installperl no longer installs:
o static library files of statically linked extensions when a shared
perl library is being used. (They are not needed. See "Windows"
below).
o SIGNATURE and PAUSE*.pub (CPAN files)
o NOTES and PATCHING (ExtUtils files)
o perlld and ld2 (Cygwin files)
Platform Specific Changes
There are improved hints for AIX, Cygwin, DEC/OSF, FreeBSD, HP/UX, Irix
6 Linux, MachTen, NetBSD, OS/390, QNX, SCO, Solaris, SunOS, System V
Release 5.x (UnixWare 7, OpenUNIX 8), Ultrix, UMIPS, uts and VOS.
FreeBSD
o Drop "-std=c89" and "-ansi" if using "long long" as the main
integral type, else in FreeBSD 6.2 (and perhaps other releases),
system headers do not declare some functions required by perl.
Solaris
o Starting with Solaris 10, we do not want versioned shared
libraries, because those often indicate a private use only library.
These problems could often be triggered when SUNWbdb (Berkeley DB)
was installed. Hence if Solaris 10 is detected set
"ignore_versioned_solibs=y".
VMS
o Allow IEEE math to be deselected on OpenVMS I64 (but it remains the
default).
o Record IEEE usage in "config.h"
o Help older VMS compilers by using "ccflags" when building
"munchconfig.exe".
o Don't try to build old "Thread" extension on VMS when
"-Duseithreads" has been chosen.
o Passing a raw string of "NaN" to nawk causes a core dump - so the
string has been changed to "*NaN*"
o t/op/stat.t tests will now test hard links on VMS if they are
supported.
Windows
o When using a shared perl library installperl no longer installs
static library files, import library files and export library files
(of statically linked extensions) and empty bootstrap files (of
dynamically linked extensions). This fixes a problem building PAR-
Packer on Win32 with a debug build of perl.
o Various improvements to the win32 build process, including support
for Visual C++ 2005 Express Edition (aka Visual C++ 8.x).
o perl.exe will now have an icon if built with MinGW or Borland.
o Improvements to the perl-static.exe build process.
o Add Win32 makefile option to link all extensions statically.
o The WinCE directory has been merged into the Win32 directory.
o "setlocale" tests have been re-enabled for Windows XP onwards.
Selected Bug Fixes
Unicode
Many many bugs related to the internal Unicode implementation (UTF-8)
have been fixed. In particular, long standing bugs related to returning
Unicode via "tie", overloading or $@ are now gone, some of which were
never reported.
"unpack" will internally convert the string back from UTF-8 on numeric
types. This is a compromise between the full consistency now in 5.10,
and the current behaviour, which is often used as a "feature" on string
types.
Using ":crlf" and "UTF-16" IO layers together will now work.
Fixed problems with "split", Unicode "/\s+/" and "/ \0/".
Fixed bug RT #40641 - encoding of Unicode characters in regular
expressions.
Fixed a bug where using certain patterns in a regexp led to a panic.
[RT #45337]
Perl no longer segfaults (due to infinite internal recursion) if the
locale's character is not UTF-8 [RT #41442]:
use open ':locale';
print STDERR "\x{201e}"; # „
PerlIO
Inconsistencies have been fixed in the reference counting PerlIO uses
to keep track of Unix file descriptors, and the API used by XS code to
manage getting and releasing "FILE *"s
Magic
Several bugs have been fixed in Magic, the internal system used to
implement features such as "tie", tainting and threads sharing.
"undef @array" on a tied array now correctly calls the "CLEAR" method.
Some of the bitwise ops were not checking whether their arguments were
magical before using them. [RT #24816]
Magic is no longer invoked twice by the expression "\&$x"
A bug with assigning large numbers and tainting has been resolved. [RT
#40708]
A new entry has been added to the MAGIC vtable - "svt_local". This is
used when copying magic to the new value during "local", allowing
certain problems with localising shared variables to be resolved.
For the implementation details, see "Magic Virtual Tables" in perlguts.
Reblessing overloaded objects now works
Internally, perl object-ness is on the referent, not the reference,
even though methods can only be called via a reference. However, the
original implementation of overloading stored flags related to
overloading on the reference, relying on the flags being copied when
the reference was copied, or set at the creation of a new reference.
This manifests in a bug - if you rebless an object from a class that
has overloading, into one that does not, then any other existing
references think that they (still) point to an overloaded object,
choose these C code paths, and then throw errors. Analogously,
blessing into an overloaded class when other references exist will
result in them not using overloading.
The implementation has been fixed for 5.10, but this fix changes the
semantics of flag bits, so is not binary compatible, so can't be
applied to 5.8.9. However, 5.8.9 has a work-around that implements the
same bug fix. If the referent has multiple references, then all the
other references are located and corrected. A full search is avoided
whenever possible by scanning lexicals outwards from the current
subroutine, and the argument stack.
A certain well known Linux vendor applied incomplete versions of this
bug fix to their /usr/bin/perl and then prematurely closed bug reports
about performance issues without consulting back upstream. This not
being enough, they then proceeded to ignore the necessary fixes to
these unreleased changes for 11 months, until massive pressure was
applied by their long-suffering paying customers, catalysed by the
failings being featured on a prominent blog and Slashdot.
"strict" now propagates correctly into string evals
Under 5.8.8 and earlier:
$ perl5.8.8 -e 'use strict; eval "use foo bar" or die $@'
Can't locate foo.pm in @INC (@INC contains: ... .) at (eval 1) line 2.
BEGIN failed--compilation aborted at (eval 1) line 2.
Under 5.8.9 and later:
$ perl5.8.9 -e 'use strict; eval "use foo bar" or die $@'
Bareword "bar" not allowed while "strict subs" in use at (eval 1) line 1.
This may cause problems with programs that parse the error message and
rely on the buggy behaviour.
Other fixes
o The tokenizer no longer treats "=cute" (and other words beginning
with "=cut") as a synonym for "=cut".
o Calling "CORE::require"
"CORE::require" and "CORE::do" were always parsed as "require" and
"do" when they were overridden. This is now fixed.
o Stopped memory leak on long /etc/groups entries.
o "while (my $x ...) { ...; redo }" shouldn't "undef $x".
In the presence of "my" in the conditional of a "while()",
"until()", or "for(;;)" loop, we now add an extra scope to the body
so that "redo" doesn't "undef" the lexical.
o The "encoding" pragma now correctly ignores anything following an
"@" character in the "LC_ALL" and "LANG" environment variables. [RT
# 49646]
o A segfault observed with some gcc 3.3 optimisations is resolved.
o A possible segfault when "unpack" used in scalar context with "()"
groups is resolved. [RT #50256]
o Resolved issue where $! could be changed by a signal handler
interrupting a "system" call.
o Fixed bug RT #37886, symbolic dereferencing was allowed in the
argument of "defined" even under the influence of "use strict
'refs'".
o Fixed bug RT #43207, where "lc"/"uc" inside "sort" affected the
return value.
o Fixed bug RT #45607, where "*{"BONK"} = \&{"BONK"}" didn't work
correctly.
o Fixed bug RT #35878, croaking from a XSUB called via "goto &xsub"
corrupts perl internals.
o Fixed bug RT #32539, DynaLoader.o is moved into libperl.so to avoid
the need to statically link DynaLoader into the stub perl
executable. With this libperl.so provides everything needed to get
a functional embedded perl interpreter to run.
o Fix bug RT #36267 so that assigning to a tied hash doesn't change
the underlying hash.
o Fix bug RT #6006, regexp replaces using large replacement variables
fail some of the time, i.e. when substitution contains something
like "${10}" (note the bracket) instead of just $10.
o Fix bug RT #45053, "Perl_newCONSTSUB()" is now thread safe.
Platform Specific Fixes
Darwin / MacOS X
o Various improvements to 64 bit builds.
o Mutex protection added in "PerlIOStdio_close()" to avoid race
conditions. Hopefully this fixes failures in the threads tests
free.t and blocks.t.
o Added forked terminal support to the debugger, with the ability to
update the window title.
OS/2
o A build problem with specifying "USE_MULTI" and "USE_ITHREADS" but
without "USE_IMP_SYS" has been fixed.
o "OS2::REXX" upgraded to version 1.04
Tru64
o Aligned floating point build policies for cc and gcc.
RedHat Linux
o Revisited a patch from 5.6.1 for RH7.2 for Intel's icc [RT #7916],
added an additional check for $Config{gccversion}.
Solaris/i386
o Use "-DPTR_IS_LONG" when using 64 bit integers
VMS
o Fixed "PerlIO::Scalar" in-memory file record-style reads.
o pipe shutdown at process exit should now be more robust.
o Bugs in VMS exit handling tickled by "Test::Harness" 2.64 have been
fixed.
o Fix "fcntl()" locking capability test in configure.com.
o Replaced "shrplib='define'" with "useshrplib='true'" on VMS.
Windows
o "File::Find" used to fail when the target directory is a bare drive
letter and "no_chdir" is 1 (the default is 0). [RT #41555]
o A build problem with specifying "USE_MULTI" and "USE_ITHREADS" but
without "USE_IMP_SYS" has been fixed.
o The process id is no longer truncated to 16 bits on some Windows
platforms ( http://bugs.activestate.com/show_bug.cgi?id=72443 )
o Fixed bug RT #54828 in perlio.c where calling "binmode" on Win32
and Cygwin may cause a segmentation fault.
Smaller fixes
o It is now possible to overload "eq" when using "nomethod".
o Various problems using "overload" with 64 bit integers corrected.
o The reference count of "PerlIO" file descriptors is now correctly
handled.
o On VMS, escaped dots will be preserved when converted to Unix
syntax.
o "keys %+" no longer throws an 'ambiguous' warning.
o Using "#!perl -d" could trigger an assertion, which has been fixed.
o Don't stringify tied code references in @INC when calling
"require".
o Code references in @INC report the correct file name when
"__FILE__" is used.
o Width and precision in sprintf didn't handle characters above 255
correctly. [RT #40473]
o List slices with indices out of range now work more consistently.
[RT #39882]
o A change introduced with perl 5.8.1 broke the parsing of arguments
of the form "-foo=bar" with the "-s" on the <#!> line. This has
been fixed. See http://bugs.activestate.com/show_bug.cgi?id=43483
o "tr///" is now threadsafe. Previously it was storing a swash inside
its OP, rather than in a pad.
o pod2html labels anchors more consistently and handles nested
definition lists better.
o "threads" cleanup veto has been extended to include "perl_free()"
and "perl_destruct()"
o On some systems, changes to $ENV{TZ} would not always be respected
by the underlying calls to "localtime_r()". Perl now forces the
inspection of the environment on these systems.
o The special variable $^R is now more consistently set when
executing regexps using the "(?{...})" construct. In particular,
it will still be set even if backreferences or optional sub-
patterns "(?:...)?" are used.
New or Changed Diagnostics
panic: sv_chop %s
This new fatal error occurs when the C routine "Perl_sv_chop()" was
passed a position that is not within the scalar's string buffer. This
is caused by buggy XS code, and at this point recovery is not possible.
Maximal count of pending signals (%s) exceeded
This new fatal error occurs when the perl process has to abort due to
too many pending signals, which is bound to prevent perl from being
able to handle further incoming signals safely.
panic: attempt to call %s in %s
This new fatal error occurs when the ACL version file test operator is
used where it is not available on the current platform. Earlier checks
mean that it should never be possible to get this.
FETCHSIZE returned a negative value
New error indicating that a tied array has claimed to have a negative
number of elements.
Can't upgrade %s (%d) to %d
Previously the internal error from the SV upgrade code was the less
informative Can't upgrade that kind of scalar. It now reports the
current internal type, and the new type requested.
%s argument is not a HASH or ARRAY element or a subroutine
This error, thrown if an invalid argument is provided to "exists" now
correctly includes "or a subroutine". [RT #38955]
Cannot make the non-overridable builtin %s fatal
This error in "Fatal" previously did not show the name of the builtin
in question (now represented by %s above).
Unrecognized character '%s' in column %d
This error previously did not state the column.
Offset outside string
This can now also be generated by a "seek" on a file handle using
"PerlIO::scalar".
Invalid escape in the specified encoding in regexp; marked by <-- HERE in
m/%s/
New error, introduced as part of the fix to RT #40641 to handle
encoding of Unicode characters in regular expression comments.
Your machine doesn't support dump/undump.
A more informative fatal error issued when calling "dump" on Win32 and
Cygwin. (Given that the purpose of "dump" is to abort with a core dump,
and core dumps can't be produced on these platforms, this is more
useful than silently exiting.)
Changed Internals
The perl sources can now be compiled with a C++ compiler instead of a C
compiler. A necessary implementation details is that under C++, the
macro "XS" used to define XSUBs now includes an "extern "C""
definition. A side effect of this is that C++ code that used the
construction
typedef XS(SwigPerlWrapper);
now needs to be written
typedef XSPROTO(SwigPerlWrapper);
using the new "XSPROTO" macro, in order to compile. C extensions are
unaffected, although C extensions are encouraged to use "XSPROTO" too.
This change was present in the 5.10.0 release of perl, so any actively
maintained code that happened to use this construction should already
have been adapted. Code that needs changing will fail with a
compilation error.
"set" magic on localizing/assigning to a magic variable will now only
trigger for container magics, i.e. it will for %ENV or %SIG but not for
$#array.
The new API macro "newSVpvs()" can be used in place of constructions
such as "newSVpvn("ISA", 3)". It takes a single string constant, and at
C compile time determines its length.
The new API function "Perl_newSV_type()" can be used as a more
efficient replacement of the common idiom
sv = newSV(0);
sv_upgrade(sv, type);
Similarly "Perl_newSVpvn_flags()" can be used to combine
"Perl_newSVpv()" with "Perl_sv_2mortal()" or the equivalent
"Perl_sv_newmortal()" with "Perl_sv_setpvn()"
Two new macros "mPUSHs()" and "mXPUSHs()" are added, to make it easier
to push mortal SVs onto the stack. They were then used to fix several
bugs where values on the stack had not been mortalised.
A "Perl_signbit()" function was added to test the sign of an "NV". It
maps to the system one when available.
"Perl_av_reify()", "Perl_lex_end()", "Perl_mod()", "Perl_op_clear()",
"Perl_pop_return()", "Perl_qerror()", "Perl_setdefout()",
"Perl_vivify_defelem()" and "Perl_yylex()" are now visible to
extensions. This was required to allow "Data::Alias" to work on
Windows.
"Perl_find_runcv()" is now visible to perl core extensions. This was
required to allow "Sub::Current" to work on Windows.
"ptr_table*" functions are now available in unthreaded perl. "Storable"
takes advantage of this.
There have been many small cleanups made to the internals. In
particular, "Perl_sv_upgrade()" has been simplified considerably, with
a straight-through code path that uses "memset()" and "memcpy()" to
initialise the new body, rather than assignment via multiple temporary
variables. It has also benefited from simplification and de-duplication
of the arena management code.
A lot of small improvements in the code base were made due to reports
from the Coverity static code analyzer.
Corrected use and documentation of "Perl_gv_stashpv()",
"Perl_gv_stashpvn()", "Perl_gv_stashsv()" functions (last parameter is
a bitmask, not boolean).
"PERL_SYS_INIT", "PERL_SYS_INIT3" and "PERL_SYS_TERM" macros have been
changed into functions.
"PERLSYS_TERM" no longer requires a context. "PerlIO_teardown()" is now
called without a context, and debugging output in this function has
been disabled because that required that an interpreter was present, an
invalid assumption at termination time.
All compile time options which affect binary compatibility have been
grouped together into a global variable ("PL_bincompat_options").
The values of "PERL_REVISION", "PERL_VERSION" and "PERL_SUBVERSION" are
now baked into global variables (and hence into any shared perl
library). Additionally under "MULTIPLICITY", the perl executable now
records the size of the interpreter structure (total, and for this
version). Coupled with "PL_bincompat_options" this will allow 5.8.10
(and later), when compiled with a shared perl library, to perform
sanity checks in "main()" to verify that the shared library is indeed
binary compatible.
Symbolic references can now have embedded NULs. The new public function
"Perl_get_cvn_flags()" can be used in extensions if you have to handle
them.
Macro cleanups
The core code, and XS code in ext that is not dual-lived on CPAN, no
longer uses the macros "PL_na", "NEWSV()", "Null()", "Nullav",
"Nullcv", "Nullhv", "Nullhv" etc. Their use is discouraged in new code,
particularly "PL_na", which is a small performance hit.
New Tests
Many modules updated from CPAN incorporate new tests. Some core
specific tests have been added:
ext/DynaLoader/t/DynaLoader.t
Tests for the "DynaLoader" module.
t/comp/fold.t
Tests for compile-time constant folding.
t/io/pvbm.t
Tests incorporated from 5.10.0 which check that there is no
unexpected interaction between the internal types "PVBM" and
"PVGV".
t/lib/proxy_constant_subs.t
Tests for the new form of constant subroutines.
t/op/attrhand.t
Tests for "Attribute::Handlers".
t/op/dbm.t
Tests for "dbmopen".
t/op/inccode-tie.t
Calls all tests in t/op/inccode.t after first tying @INC.
t/op/incfilter.t
Tests for source filters returned from code references in @INC.
t/op/kill0.t
Tests for RT #30970.
t/op/qrstack.t
Tests for RT #41484.
t/op/qr.t
Tests for the "qr//" construct.
t/op/regexp_qr_embed.t
Tests for the "qr//" construct within another regexp.
t/op/regexp_qr.t
Tests for the "qr//" construct.
t/op/rxcode.t
Tests for RT #32840.
t/op/studytied.t
Tests for "study" on tied scalars.
t/op/substT.t
Tests for "subst" run under "-T" mode.
t/op/symbolcache.t
Tests for "undef" and "delete" on stash entries that are bound to
subroutines or methods.
t/op/upgrade.t
Tests for "Perl_sv_upgrade()".
t/mro/package_aliases.t
MRO tests for "isa" and package aliases.
t/pod/twice.t
Tests for calling "Pod::Parser" twice.
t/run/cloexec.t
Tests for inheriting file descriptors across "exec" (close-on-
exec).
t/uni/cache.t
Tests for the UTF-8 caching code.
t/uni/chr.t
Test that strange encodings do not upset "Perl_pp_chr()".
t/uni/greek.t
Tests for RT #40641.
t/uni/latin2.t
Tests for RT #40641.
t/uni/overload.t
Tests for returning Unicode from overloaded values.
t/uni/tie.t
Tests for returning Unicode from tied variables.
Known Problems
There are no known new bugs.
However, programs that rely on bugs that have been fixed will have
problems. Also, many bug fixes present in 5.10.0 can't be back-ported
to the 5.8.x branch, because they require changes that are binary
incompatible, or because the code changes are too large and hence too
risky to incorporate.
We have only limited volunteer labour, and the maintenance burden is
getting increasingly complex. Hence this 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. Alternatively, if business requirements constrain you to
continue to use 5.8.x, you may wish to consider commercial support from
firms such as ActiveState.
Platform Specific Notes
Win32
"readdir()", "cwd()", $^X and @INC now use the alternate (short)
filename if the long name is outside the current codepage (Jan Dubois).
Updated Modules
o "Win32" upgraded to version 0.38. Now has a documented 'WinVista'
response from "GetOSName" and support for Vista's privilege
elevation in "IsAdminUser". Support for Unicode characters in path
names. Improved cygwin and Win64 compatibility.
o "Win32API" updated to 0.1001_01
o "killpg()" support added to "MSWin32" (Jan Dubois).
o "File::Spec::Win32" upgraded to version 3.2701
OS/2
Updated Modules
o "OS2::Process" upgraded to 1.03
Ilya Zakharevich has added and documented several "Window*" and
"Clipbrd*" functions.
o "OS2::REXX::DLL", "OS2::REXX" updated to version 1.03
VMS
Updated Modules
o "DCLsym" upgraded to version 1.03
o "Stdio" upgraded to version 2.4
o "VMS::XSSymSet" upgraded to 1.1.
Obituary
Nick Ing-Simmons, long time Perl hacker, author of the "Tk" and
"Encode" modules, perlio.c in the core, and 5.003_02 pumpking, died of
a heart attack on 25th September 2006. He will be missed.
Acknowledgements
Some of the work in this release was funded by a TPF grant.
Steve Hay worked behind the scenes working out the causes of the
differences between core modules, their CPAN releases, and previous
core releases, and the best way to rectify them. He doesn't want to do
it again. I know this feeling, and I'm very glad he did it this time,
instead of me.
Paul Fenwick assembled a team of 18 volunteers, who broke the back of
writing this document. In particular, Bradley Dean, Eddy Tan, and
Vincent Pit provided half the team's contribution.
Schwern verified the list of updated module versions, correcting quite
a few errors that I (and everyone else) had missed, both wrongly stated
module versions, and changed modules that had not been listed.
The crack Berlin-based QA team of Andreas Koenig and Slaven Rezic
tirelessly re-built snapshots, tested most everything CPAN against
them, and then identified the changes responsible for any module
regressions, ensuring that several show-stopper bugs were stomped
before the first release candidate was cut.
The other core committers contributed most of the changes, and applied
most of the patches sent in by the hundreds of contributors listed in
AUTHORS.
And obviously, Larry Wall, without whom we wouldn't have Perl.
Reporting Bugs
If you find what you think is a bug, you might check the articles
recently posted to the comp.lang.perl.misc newsgroup and the perl bug
database at http://bugs.perl.org. There may also be information at
http://www.perl.org, the Perl Home Page.
If you believe you have an unreported bug, please run the perlbug
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 "perl -V", will be sent off to perlbug AT perl.org to be analysed by
the Perl porting team. You can browse and search the Perl 5 bugs at
http://bugs.perl.org/
If the bug you are reporting has security implications, which make it
inappropriate to send to a publicly archived mailing list, then please
send it to perl5-security-report AT perl.org. This points to a closed
subscription unarchived mailing list, which includes all the core
committers, who will be able to help assess the impact of issues,
figure out a resolution, and help co-ordinate the release of patches to
mitigate or fix the problem across all platforms on which Perl is
supported. Please only use this address for security issues in the Perl
core, not for modules independently distributed on CPAN.
SEE ALSO
The Changes file for exhaustive details on what changed.
The INSTALL file for how to build Perl.
The README file for general stuff.
The Artistic and Copying files for copyright information.
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