PERL5134DELTA(1) Perl Programmers Reference Guide PERL5134DELTA(1)NAMEperl5134delta - what is new for perl v5.13.4
DESCRIPTION
This document describes differences between the 5.13.4 release and the
5.13.3 release.
If you are upgrading from an earlier release such as 5.13.2, first read
perl5133delta, which describes differences between 5.13.2 and 5.13.3.
Core Enhancements
"srand()" now returns the seed
This allows programs that need to have repeatable results to not have
to come up with their own seed generating mechanism. Instead, they can
use "srand()" and somehow stash the return for future use. Typical is
a test program which has too many combinations to test comprehensively
in the time available to it each run. It can test a random subset each
time, and should there be a failure, log the seed used for that run so
that it can later be used to reproduce the exact results.
"\N{name}" and "charnames" enhancements
"\N{}", "charnames::vianame", "charnames::viacode" now know about every
character in Unicode. Previously, they didn't know about the Hangul
syllables nor a number of CJK (Chinese/Japanese/Korean) characters.
Incompatible Changes
Declare API incompatibility between blead releases
Only stable releases (5.10.x, 5.12.x, 5.14.x, ...) guarantee binary
compatibility with each other, while blead releases (5.13.x, 5.15.x,
...) often break this compatibility. However, prior to perl 5.13.4, all
blead releases had the same "PERL_API_REVISION", "PERL_API_VERSION",
and "PERL_API_SUBVERSION", effectively declaring them as binary
compatible, which they weren't. From now on, blead releases will have a
"PERL_API_SUBVERSION" equal to their "PERL_SUBVERSION", explicitly
marking them as incompatible with each other.
Maintenance releases of stable perl versions will continue to make no
intentionally incompatible API changes.
Check API compatibility when loading XS modules
When perl's API changes in incompatible ways (which usually happens
between every major release), XS modules compiled for previous versions
of perl will not work anymore. They will need to be recompiled against
the new perl.
In order to ensure that modules are recompiled, and to prevent users
from accidentally loading modules compiled for old perls into newer
ones, the "XS_APIVERSION_BOOTCHECK" macro has been added. That macro,
which is called when loading every newly compiled extension, compares
the API version of the running perl with the version a module has been
compiled for and raises an exception if they don't match.
Binary Incompatible with all previous Perls
Some bit fields have been reordered; therefore, this release will not
be binary compatible with any previous Perl release.
Change in the parsing of certain prototypes
Functions declared with the following prototypes now behave correctly
as unary functions:
· "*"
· "\sigil"
· "\[...]"
· ";$"
· ";*"
· ";\sigil"
· ";\[...]"
Due to this bug fix, functions using the "(*)", "(;$)" and "(;*)"
prototypes are parsed with higher precedence than before. So in the
following example:
sub foo($);
foo $a < $b;
the second line is now parsed correctly as "foo($a) < $b", rather than
"foo($a < $b)". This happens when one of these operators is used in an
unparenthesised argument:
< > <= >= lt gt le ge
== != <=> eq ne cmp ~~
&
| ^
&&
|| //
.. ...
?:
= += -= *= etc.
Deprecations
List assignment to $[
After assignment to $[ has been deprecated and started to give warnings
in perl version 5.12.0, this version of perl also starts to emit a
warning when assigning to $[ in list context. This fixes an oversight
in 5.12.0.
Performance Enhancements
· Make string appending 100 times faster
When doing a lot of string appending, perl could end up allocating
a lot more memory than needed in a very inefficient way, if perl
was configured to use the system's "malloc" implementation instead
of its own.
"sv_grow", which is what's being used to allocate more memory if
necessary when appending to a string, has now been taught how to
round up the memory it requests to a certain geometric progression,
making it much faster on certain platforms and configurations. On
Win32, it's now about 100 times faster.
· For weak references, the common case of just a single weak
reference per referent has been optimised to reduce the storage
required. In this case it saves the equivalent of one small perl
array per referent.
· "XPV", "XPVIV", and "XPVNV" now only allocate the parts of the "SV"
body they actually use, saving some space.
Modules and Pragmata
New Modules and Pragmata
This release does not introduce any new modules or pragmata.
Updated Modules and Pragmata
"Archive::Tar"
Upgraded from version 1.64 to 1.68.
Among other things, the new version adds a new option to "ptar" to
allow safe creation of tarballs without world-writable files on
Windows, allowing those archives to be uploaded to CPAN.
"B::Lint"
Upgraded from version 1.11 to 1.12.
"Carp"
Upgraded from version 1.16 to 1.18.
Carp now detects incomplete caller() overrides and avoids using
bogus @DB::args. To provide backtraces, Carp relies on particular
behaviour of the caller built-in. Carp now detects if other code
has overridden this with an incomplete implementation, and modifies
its backtrace accordingly. Previously incomplete overrides would
cause incorrect values in backtraces (best case), or obscure fatal
errors (worst case)
This fixes certain cases of "Bizarre copy of ARRAY" caused by
modules overriding "caller()" incorrectly.
"Compress::Raw::Bzip2"
Upgraded from version 2.027 to 2.030.
"Compress::Raw::Zlib"
Upgraded from version 2.027 to 2.030.
"File::Spec"
Upgraded from version 3.31 to 3.31_01.
Various issues in File::Spec::VMS have been fixed.
"I18N::Langinfo"
Upgraded from version 0.03 to 0.04.
"langinfo()" now defaults to using $_ if there is no argument
given, just like the documentation always claimed it did.
"IO::Compress"
Upgraded from version 2.027 to 2.030.
"Module::CoreList"
Upgraded from version 2.36 to 2.37.
Besides listing the updated core modules of this release, it also
stops listing the "Filespec" module. That module never existed in
core. The scripts generating "Module::CoreList" confused it with
"VMS::Filespec", which actually is a core module, since the time of
perl 5.8.7.
"Test::Harness"
Upgraded from version 3.21 to 3.22.
"Test::Simple"
Upgraded from version 0.94 to 0.96.
Among many other things, subtests without a "plan" or "no_plan" now
have an implicit "done_testing()" added to them.
"Unicode::Collate"
Upgraded from version 0.53 to 0.56.
Among other things, it is now using UCA Revision 20 (based on
Unicode 5.2.0) and supports a couple of new locales.
"feature"
Upgraded from version 1.17 to 1.18.
Removed Modules and Pragmata
This release does not remove any modules or pragmata.
Documentation
Changes to Existing Documentation
perldiag
· The following existing diagnostics are now documented:
· Ambiguous use of %c resolved as operator %c
· Ambiguous use of %c{%s} resolved to %c%s
· Ambiguous use of %c{%s%s} resolved to %c%s%s
· Ambiguous use of -%s resolved as -&%s()
· Invalid strict version format (%s)
· Invalid version format (%s)
· Invalid version object
perlport
· Documented a limitation of alarm() on Win32.
perlre
· Minor fix to a multiple scalar match example.
Configuration and Compilation
· Compatibility with "C++" compilers has been improved.
· On compilers that support it, "-Wwrite-strings" is now added to
cflags by default.
Testing
· t/op/print.t has been added to test implicit printing of $_.
· t/io/errnosig.t has been added to test for restoration of of $!
when leaving signal handlers.
· t/op/tie_fetch_count.t has been added to see if "FETCH" is only
called once on tied variables.
· lib/Tie/ExtraHash.t has been added to make sure the, previously
untested, Tie::ExtraHash keeps working.
· t/re/overload.t has been added to test against string corruption in
pattern matches on overloaded objects. This is a TODO test.
Platform Support
Platform-Specific Notes
Win32
· Fixed a possible hang in t/op/readline.t.
· Fixed build process for SDK2003SP1 compilers.
· When using old 32-bit compilers, the define "_USE_32BIT_TIME_T"
will now be set in $Config{ccflags}. This improves portability
when compiling XS extensions using new compilers, but for a
perl compiled with old 32-bit compilers.
Internal Changes
Removed "PERL_POLLUTE"
The option to define "PERL_POLLUTE" to expose older 5.005 symbols
for backwards compatibility has been removed. It's use was always
discouraged, and MakeMaker contains a more specific escape hatch:
perl Makefile.PL POLLUTE=1
This can be used for modules that have not been upgraded to 5.6
naming conventions (and really should be completely obsolete by
now).
Added "PERL_STATIC_INLINE"
The "PERL_STATIC_INLINE" define has been added to provide the best-
guess incantation to use for static inline functions, if the C
compiler supports C99-style static inline. If it doesn't, it'll
give a plain "static".
"HAS_STATIC_INLINE" can be used to check if the compiler actually
supports inline functions.
Selected Bug Fixes
· A possible memory leak when using caller() to set @DB::args has
been fixed.
· Several memory leaks when loading XS modules were fixed.
· A panic in the regular expression optimizer has been fixed
(RT#75762).
· Assignments to lvalue subroutines now honor copy-on-write behavior
again, which has been broken since version 5.10.0 (RT#75656).
· Assignments to glob copies now behave just like assignments to
regular globs (RT#1804).
· Within signal handlers, $! is now implicitly localized.
· readline now honors "<>" overloading on tied arguments.
· substr(), pos(), keys(), and vec() could, when used in combination
with lvalues, result in leaking the scalar value they operate on,
and cause its destruction to happen too late. This has now been
fixed.
· Building with "PERL_GLOBAL_STRUCT", which has been broken
accidentally in 5.13.3, now works again.
Known Problems
· The changes in substr() broke "HTML::Parser" <= 3.66. A fixed
"HTML::Parser" is available as version 3.67 on CPAN.
· The changes in prototype handling break "Switch". A patch has been
sent upstream and will hopefully appear on CPAN soon.
Acknowledgements
Perl 5.13.4 represents approximately one month of development since
Perl 5.13.3, and contains 91,200 lines of changes across 436 files from
34 authors and committers.
Thank you to the following for contributing to this release:
Abigail, Andy Armstrong, Andy Dougherty, Chas. Owens, Chip Salzenberg,
Chris 'BinGOs' Williams, Craig A. Berry, David Cantrell, David Golden,
David Mitchell, Eric Brine, Father Chrysostomos, Florian Ragwitz,
George Greer, Gerard Goossen, H.Merijn Brand, James Mastros, Jan
Dubois, Jerry D. Hedden, Joshua ben Jore, Karl Williamson, Lars DXXXXXX
XXX, Leon Brocard, Lubomir Rintel, Nicholas Clark, Paul Marquess,
Rafael Garcia-Suarez, Reini Urban, Robin Barker, Slaven Rezic, Steve
Peters, Tony Cook, Wolfram Humann, Zefram
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://rt.perl.org/perlbug/ . 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@perl.org to be analysed by
the Perl porting team.
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@perl.org. This points to a closed
subscription unarchived mailing list, which includes all the core
committers, who 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 an explanation of how to view 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.
perl v5.14.2 2011-09-26 PERL5134DELTA(1)
