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PERL572DELTA(1)
NAME
perl572delta - what's new for perl v5.7.2
DESCRIPTION
This document describes differences between the 5.7.1 release and the 5.7.2
release.
(To view the differences between the 5.6.0 release and the 5.7.0 release,
see perl570delta. To view the differences between the 5.7.0 release and
the 5.7.1 release, see perl571delta.)
Security Vulnerability Closed
(This change was already made in 5.7.0 but bears repeating here.)
A security vulnerability affecting all Perl versions prior to 5.6.1 was
found in August 2000. The vulnerability does not affect default
installations and as far as is known affects only the Linux platform.
You should upgrade your Perl to 5.6.1 as soon as possible. Patches for
earlier releases exist but using the patches require full recompilation
from the source code anyway, so 5.6.1 is your best choice.
See http://www.cpan.org/src/5.0/sperl-2000-08-05/sperl-2000-08-05.txt for
more information.
Incompatible Changes
64-bit platforms and malloc
If your pointers are 64 bits wide, the Perl malloc is no more being used
because it simply does not work with 8-byte pointers. Also, usually the
system malloc on such platforms are much better optimized for such large
memory models than the Perl malloc.
AIX Dynaloading
The AIX dynaloading now uses in AIX releases 4.3 and newer the native
dlopen interface of AIX instead of the old emulated interface. This change
will probably break backward compatibility with compiled modules. The
change was made to make Perl more compliant with other applications like
modperl which are using the AIX native interface.
Socket Extension Dynamic in VMS
The Socket extension is now dynamically loaded instead of being statically
built in. This may or may not be a problem with ancient TCP/IP stacks of
VMS: we do not know since we weren't able to test Perl in such
configurations.
Different Definition of the Unicode Character Classes \p{In...}
As suggested by the Unicode consortium, the Unicode character classes now
prefer scripts as opposed to blocks (as defined by Unicode); in Perl, when
the "\p{In....}" and the "\p{In....}" regular expression constructs are
used. This has changed the definition of some of those character classes.
The difference between scripts and blocks is that scripts are the glyphs
used by a language or a group of languages, while the blocks are more
artificial groupings of 256 characters based on the Unicode numbering.
In general this change results in more inclusive Unicode character classes,
but changes to the other direction also do take place: for example while
the script "Latin" includes all the Latin characters and their various
diacritic-adorned versions, it does not include the various punctuation or
digits (since they are not solely "Latin").
Changes in the character class semantics may have happened if a script and
a block happen to have the same name, for example "Hebrew". In such cases
the script wins and "\p{InHebrew}" now means the script definition of
Hebrew. The block definition in still available, though, by appending
"Block" to the name: "\p{InHebrewBlock}" means what "\p{InHebrew}" meant in
perl 5.6.0. For the full list of affected character classes, see "Blocks"
in perlunicode.
Deprecations
The current user-visible implementation of pseudo-hashes (the weird use of
the first array element) is deprecated starting from Perl 5.8.0 and will be
removed in Perl 5.10.0, and the feature will be implemented differently.
Not only is the current interface rather ugly, but the current
implementation slows down normal array and hash use quite noticeably. The
"fields" pragma interface will remain available.
The syntaxes "@a->[...]" and "@h->{...}" have now been deprecated.
The suidperl is also considered to be too much a risk to continue
maintaining and the suidperl code is likely to be removed in a future
release.
The "package;" syntax ("package" without an argument has been deprecated.
Its semantics were never that clear and its implementation even less so.
If you have used that feature to disallow all but fully qualified
variables, "use strict;" instead.
The chdir(undef) and chdir('') behaviors to match chdir() has been
deprecated. In future versions, chdir(undef) and chdir('') will simply
fail.
Core Enhancements
In general a lot of fixing has happened in the area of Perl's understanding
of numbers, both integer and floating point. Since in many systems the
standard number parsing functions like "strtoul()" and "atof()" seem to
have bugs, Perl tries to work around their deficiencies. This results
hopefully in more accurate numbers.
· The rules for allowing underscores (underbars) in numeric constants
have been relaxed and simplified: now you can have an underscore
between digits.
· GMAGIC (right-hand side magic) could in many cases such as string
concatenation be invoked too many times.
· Lexicals I: lexicals outside an eval "" weren't resolved correctly
inside a subroutine definition inside the eval "" if they were not
already referenced in the top level of the eval""ed code.
· Lexicals II: lexicals leaked at file scope into subroutines that were
declared before the lexicals.
· Lvalue subroutines can now return "undef" in list context.
· The "op_clear" and "op_null" are now exported.
· A new special regular expression variable has been introduced: $^N,
which contains the most-recently closed group (submatch).
· utime now supports "utime undef, undef, @files" to change the file
timestamps to the current time.
· The Perl parser has been stress tested using both random input and
Markov chain input.
· "eval "v200"" now works.
· VMS now works under PerlIO.
· END blocks are now run even if you exit/die in a BEGIN block. The
execution of END blocks is now controlled by PL_exit_flags &
PERL_EXIT_DESTRUCT_END. This enables the new behaviour for perl
embedders. This will default in 5.10. See perlembed.
Modules and Pragmata
New Modules and Distributions
· Attribute::Handlers - Simpler definition of attribute handlers
· ExtUtils::Constant - generate XS code to import C header constants
· I18N::Langinfo - query locale information
· I18N::LangTags - functions for dealing with RFC3066-style language tags
· libnet - a collection of perl5 modules related to network programming
Perl installation leaves libnet unconfigured, use libnetcfg to
configure.
· List::Util - selection of general-utility list subroutines
· Locale::Maketext - framework for localization
· Memoize - Make your functions faster by trading space for time
· NEXT - pseudo-class for method redispatch
· Scalar::Util - selection of general-utility scalar subroutines
· Test::More - yet another framework for writing test scripts
· Test::Simple - Basic utilities for writing tests
· Time::HiRes - high resolution ualarm, usleep, and gettimeofday
· Time::Piece - Object Oriented time objects
(Previously known as Time::Object.)
· Time::Seconds - a simple API to convert seconds to other date values
· UnicodeCD - Unicode Character Database
Updated And Improved Modules and Pragmata
· B::Deparse module has been significantly enhanced. It now can deparse
almost all of the standard test suite (so that the tests still
succeed). There is a make target "test.deparse" for trying this out.
· Class::Struct now assigns the array/hash element if the accessor is
called with an array/hash element as the sole argument.
· Cwd extension is now (even) faster.
· DB_File extension has been updated to version 1.77.
· Fcntl, Socket, and Sys::Syslog have been rewritten to use the new-style
constant dispatch section (see ExtUtils::Constant).
· File::Find is now (again) reentrant. It also has been made more
portable.
· File::Glob now supports "GLOB_LIMIT" constant to limit the size of the
returned list of filenames.
· IO::Socket::INET now supports "LocalPort" of zero (usually meaning that
the operating system will make one up.)
· The vars pragma now supports declaring fully qualified variables.
(Something that "our()" does not and will not support.)
Utility Changes
· The emacs/e2ctags.pl is now much faster.
· h2ph now supports C trigraphs.
· h2xs uses the new ExtUtils::Constant module which will affect newly
created extensions that define constants. Since the new code is more
correct (if you have two constants where the first one is a prefix of
the second one, the first constant never gets defined), less lossy (it
uses integers for integer constant, as opposed to the old code that
used floating point numbers even for integer constants), and slightly
faster, you might want to consider regenerating your extension code
(the new scheme makes regenerating easy). h2xs now also supports C
trigraphs.
· libnetcfg has been added to configure the libnet.
· The Pod::Html (and thusly pod2html) now allows specifying a cache
directory.
New Documentation
· Locale::Maketext::TPJ13 is an article about software localization,
originally published in The Perl Journal #13, republished here with
kind permission.
· More README.$PLATFORM files have been converted into pod, which also
means that they also be installed as perl$PLATFORM documentation files.
The new files are perlapollo, perlbeos, perldgux, perlhurd, perlmint,
perlnetware, perlplan9, perlqnx, and perltru64.
· The Todo and Todo-5.6 files have been merged into perltodo.
· Use of the gprof tool to profile Perl has been documented in perlhack.
There is a make target "perl.gprof" for generating a gprofiled Perl
executable.
Installation and Configuration Improvements
New Or Improved Platforms
· AIX should now work better with gcc, threads, and 64-bitness. Also the
long doubles support in AIX should be better now. See perlaix.
· AtheOS ( http://www.atheos.cx/ ) is a new platform.
· DG/UX platform now supports the 5.005-style threads. See perldgux.
· DYNIX/ptx platform (a.k.a. dynixptx) is supported at or near osvers
4.5.2.
· Several Mac OS (Classic) portability patches have been applied. We
hope to get a fully working port by 5.8.0. (The remaining problems
relate to the changed IO model of Perl.) See perlmacos.
· Mac OS X (or Darwin) should now be able to build Perl even on HFS+
filesystems. (The case-insensitivity confused the Perl build process.)
· NetWare from Novell is now supported. See perlnetware.
· The Amdahl UTS UNIX mainframe platform is now supported.
Generic Improvements
· In AFS installations one can configure the root of the AFS to be
somewhere else than the default /afs by using the Configure parameter
"-Dafsroot=/some/where/else".
· The version of Berkeley DB used when the Perl (and, presumably, the
DB_File extension) was built is now available as
@Config{qw(db_version_major db_version_minor db_version_patch)} from
Perl and as "DB_VERSION_MAJOR_CFG DB_VERSION_MINOR_CFG
DB_VERSION_PATCH_CFG" from C.
· The Thread extension is now not built at all under ithreads ("Configure
-Duseithreads") because it wouldn't work anyway (the Thread extension
requires being Configured with "-Duse5005threads").
· The "B::Deparse" compiler backend has been so significantly improved
that almost the whole Perl test suite passes after being deparsed. A
make target has been added to help in further testing: "make
test.deparse".
Selected Bug Fixes
· The autouse pragma didn't work for Multi::Part::Function::Names.
· The behaviour of non-decimal but numeric string constants such as
"0x23" was platform-dependent: in some platforms that was seen as 35,
in some as 0, in some as a floating point number (don't ask). This
was caused by Perl using the operating system libraries in a situation
where the result of the string to number conversion is undefined: now
Perl consistently handles such strings as zero in numeric contexts.
· dprofpp -R didn't work.
· PERL5OPT with embedded spaces didn't work.
· Sys::Syslog ignored the "LOG_AUTH" constant.
Platform Specific Changes and Fixes
· Some versions of glibc have a broken modfl(). This affects builds with
"-Duselongdouble". This version of Perl detects this brokenness and
has a workaround for it. The glibc release 2.2.2 is known to have
fixed the modfl() bug.
New or Changed Diagnostics
· In the regular expression diagnostics the "<< HERE" marker introduced
in 5.7.0 has been changed to be "<-- HERE" since too many people found
the "<<" to be too similar to here-document starters.
· If you try to "pack" in perlfunc a number less than 0 or larger than
255 using the "C" format you will get an optional warning. Similarly
for the "c" format and a number less than -128 or more than 127.
· Certain regex modifiers such as "(?o)" make sense only if applied to
the entire regex. You will an optional warning if you try to do
otherwise.
· Using arrays or hashes as references (e.g. "%foo->{bar}" has been
deprecated for a while. Now you will get an optional warning.
Source Code Enhancements
MAGIC constants
The MAGIC constants (e.g. 'P') have been macrofied (e.g. "PERL_MAGIC_TIED")
for better source code readability and maintainability.
Better commented code
perly.c, sv.c, and sv.h have now been extensively commented.
Regex pre-/post-compilation items matched up
The regex compiler now maintains a structure that identifies nodes in the
compiled bytecode with the corresponding syntactic features of the original
regex expression. The information is attached to the new "offsets" member
of the "struct regexp". See perldebguts for more complete information.
gcc -Wall
The C code has been made much more "gcc -Wall" clean. Some warning
messages still remain, though, so if you are compiling with gcc you will
see some warnings about dubious practices. The warnings are being worked
on.
New Tests
Several new tests have been added, especially for the lib subsection.
The tests are now reported in a different order than in earlier Perls.
(This happens because the test scripts from under t/lib have been moved to
be closer to the library/extension they are testing.)
Known Problems
Note that unlike other sections in this document (which describe changes
since 5.7.0) this section is cumulative containing known problems for all
the 5.7 releases.
AIX
· In AIX 4.2 Perl extensions that use C++ functions that use statics may
have problems in that the statics are not getting initialized. In
newer AIX releases this has been solved by linking Perl with the libC_r
library, but unfortunately in AIX 4.2 the said library has an obscure
bug where the various functions related to time (such as time() and
gettimeofday()) return broken values, and therefore in AIX 4.2 Perl is
not linked against the libC_r.
· vac 5.0.0.0 May Produce Buggy Code For Perl
The AIX C compiler vac version 5.0.0.0 may produce buggy code,
resulting in few random tests failing, but when the failing tests are
run by hand, they succeed. We suggest upgrading to at least vac
version 5.0.1.0, that has been known to compile Perl correctly. "lslpp
-L|grep vac.C" will tell you the vac version.
Amiga Perl Invoking Mystery
One cannot call Perl using the "volume:" syntax, that is, "perl -v" works,
but for example "bin:perl -v" doesn't. The exact reason is known but the
current suspect is the ixemul library.
lib/ftmp-security tests warn 'system possibly insecure'
Don't panic. Read INSTALL 'make test' section instead.
Cygwin intermittent failures of lib/Memoize/t/expire_file 11 and 12
The subtests 11 and 12 sometimes fail and sometimes work.
HP-UX lib/io_multihomed Fails When LP64-Configured
The lib/io_multihomed test may hang in HP-UX if Perl has been configured to
be 64-bit. Because other 64-bit platforms do not hang in this test, HP-UX
is suspect. All other tests pass in 64-bit HP-UX. The test attempts to
create and connect to "multihomed" sockets (sockets which have multiple IP
addresses).
HP-UX lib/posix Subtest 9 Fails When LP64-Configured
If perl is configured with -Duse64bitall, the successful result of the
subtest 10 of lib/posix may arrive before the successful result of the
subtest 9, which confuses the test harness so much that it thinks the
subtest 9 failed.
Linux With Sfio Fails op/misc Test 48
No known fix.
OS/390
OS/390 has rather many test failures but the situation is actually better
than it was in 5.6.0, it's just that so many new modules and tests have
been added.
Failed Test Stat Wstat Total Fail Failed List of Failed
-----------------------------------------------------------------------------
../ext/B/Deparse.t 14 1 7.14% 14
../ext/B/Showlex.t 1 1 100.00% 1
../ext/Encode/Encode/Tcl.t 610 13 2.13% 592 594 596 598
600 602 604-610
../ext/IO/lib/IO/t/io_unix.t 113 28928 5 3 60.00% 3-5
../ext/POSIX/POSIX.t 29 1 3.45% 14
../ext/Storable/t/lock.t 255 65280 5 3 60.00% 3-5
../lib/locale.t 129 33024 117 19 16.24% 99-117
../lib/warnings.t 434 1 0.23% 75
../lib/ExtUtils.t 27 1 3.70% 25
../lib/Math/BigInt/t/bigintpm.t 1190 1 0.08% 1145
../lib/Unicode/UCD.t 81 48 59.26% 1-16 49-64 66-81
../lib/User/pwent.t 9 1 11.11% 4
op/pat.t 660 6 0.91% 242-243 424-425
626-627
op/split.t 0 9 ?? ?? % ??
op/taint.t 174 3 1.72% 156 162 168
op/tr.t 70 3 4.29% 50 58-59
Failed 16/422 test scripts, 96.21% okay. 105/23251 subtests failed, 99.55% okay.
op/sprintf tests 129 and 130
The op/sprintf tests 129 and 130 are known to fail on some platforms.
Examples include any platform using sfio, and Compaq/Tandem's NonStop-UX.
The failing platforms do not comply with the ANSI C Standard, line 19ff on
page 134 of ANSI X3.159 1989 to be exact. (They produce something other
than "1" and "-1" when formatting 0.6 and -0.6 using the printf format
"%.0f", most often they produce "0" and "-0".)
Failure of Thread tests
Note that support for 5.005-style threading remains experimental.
The following tests are known to fail due to fundamental problems in the
5.005 threading implementation. These are not new failures--Perl 5.005_0x
has the same bugs, but didn't have these tests.
lib/autouse.t 4
t/lib/thr5005.t 19-20
UNICOS
· ext/POSIX/sigaction subtests 6 and 13 may fail.
· lib/ExtUtils may spuriously claim that subtest 28 failed, which is
interesting since the test only has 27 tests.
· Numerous numerical test failures
op/numconvert 209,210,217,218
op/override 7
ext/Time/HiRes/HiRes 9
lib/Math/BigInt/t/bigintpm 1145
lib/Math/Trig 25
These tests fail because of yet unresolved floating point inaccuracies.
UTS
There are a few known test failures, see perluts.
VMS
Rather many tests are failing in VMS but that actually more tests succeed
in VMS than they used to, it's just that there are many, many more tests
than there used to be.
Here are the known failures from some compiler/platform combinations.
DEC C V5.3-006 on OpenVMS VAX V6.2
[-.ext.list.util.t]tainted..............FAILED on test 3
[-.ext.posix]sigaction..................FAILED on test 7
[-.ext.time.hires]hires.................FAILED on test 14
[-.lib.file.find]taint..................FAILED on test 17
[-.lib.math.bigint.t]bigintpm...........FAILED on test 1183
[-.lib.test.simple.t]exit...............FAILED on test 1
[.lib]vmsish............................FAILED on test 13
[.op]sprintf............................FAILED on test 12
Failed 8/399 tests, 91.23% okay.
DEC C V6.0-001 on OpenVMS Alpha V7.2-1 and Compaq C V6.2-008 on OpenVMS
Alpha V7.1
[-.ext.list.util.t]tainted..............FAILED on test 3
[-.lib.file.find]taint..................FAILED on test 17
[-.lib.test.simple.t]exit...............FAILED on test 1
[.lib]vmsish............................FAILED on test 13
Failed 4/399 tests, 92.48% okay.
Compaq C V6.4-005 on OpenVMS Alpha 7.2.1
[-.ext.b]showlex........................FAILED on test 1
[-.ext.list.util.t]tainted..............FAILED on test 3
[-.lib.file.find]taint..................FAILED on test 17
[-.lib.test.simple.t]exit...............FAILED on test 1
[.lib]vmsish............................FAILED on test 13
[.op]misc...............................FAILED on test 49
Failed 6/401 tests, 92.77% okay.
Win32
In multi-CPU boxes there are some problems with the I/O buffering: some
output may appear twice.
Localising a Tied Variable Leaks Memory
use Tie::Hash;
tie my %tie_hash => 'Tie::StdHash';
...
local($tie_hash{Foo}) = 1; # leaks
Code like the above is known to leak memory every time the local() is
executed.
Self-tying of Arrays and Hashes Is Forbidden
Self-tying of arrays and hashes is broken in rather deep and hard-to-fix
ways. As a stop-gap measure to avoid people from getting frustrated at the
mysterious results (core dumps, most often) it is for now forbidden (you
will get a fatal error even from an attempt).
Variable Attributes are not Currently Usable for Tieing
This limitation will hopefully be fixed in future. (Subroutine attributes
work fine for tieing, see Attribute::Handlers).
Building Extensions Can Fail Because Of Largefiles
Some extensions like mod_perl are known to have issues with `largefiles', a
change brought by Perl 5.6.0 in which file offsets default to 64 bits wide,
where supported. Modules may fail to compile at all or compile and work
incorrectly. Currently there is no good solution for the problem, but
Configure now provides appropriate non-largefile ccflags, ldflags,
libswanted, and libs in the %Config hash (e.g.,
$Config{ccflags_nolargefiles}) so the extensions that are having problems
can try configuring themselves without the largefileness. This is
admittedly not a clean solution, and the solution may not even work at all.
One potential failure is whether one can (or, if one can, whether it's a
good idea) link together at all binaries with different ideas about file
offsets, all this is platform-dependent.
The Compiler Suite Is Still Experimental
The compiler suite is slowly getting better but is nowhere near working
order yet.
The Long Double Support is Still Experimental
The ability to configure Perl's numbers to use "long doubles", floating
point numbers of hopefully better accuracy, is still experimental. The
implementations of long doubles are not yet widespread and the existing
implementations are not quite mature or standardised, therefore trying to
support them is a rare and moving target. The gain of more precision may
also be offset by slowdown in computations (more bits to move around, and
the operations are more likely to be executed by less optimised libraries).
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.com/perl/ , 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.
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.
HISTORY
Written by Jarkko Hietaniemi <jhi@iki.fi>, with many contributions from The
Perl Porters and Perl Users submitting feedback and patches.
Send omissions or corrections to <perlbug@perl.org>.
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