PERL571DELTA(1) Perl Programmers Reference Guide PERL571DELTA(1)
perl571delta - what's new for perl v5.7.1
This document describes differences between the 5.7.0
release and the 5.7.1 release.
(To view the differences between the 5.6.0 release and the
5.7.0 release, see perl570delta.)
(This change was already made in 5.7.0 but bears repeating
here.)
A potential security vulnerability in the optional suidperl
component of Perl was identified in August 2000. suidperl
is neither built nor installed by default. As of April 2001
the only known vulnerable platform is Linux, most likely all
Linux distributions. CERT and various vendors and distribu-
tors have been alerted about the vulnerability. See
http://www.cpan.org/src/5.0/sperl-2000-08-05/sperl-2000-08-05.txt
for more information.
The problem was caused by Perl trying to report a suspected
security exploit attempt using an external program,
/bin/mail. On Linux platforms the /bin/mail program had an
undocumented feature which when combined with suidperl gave
access to a root shell, resulting in a serious compromise
instead of reporting the exploit attempt. If you don't have
/bin/mail, or if you have 'safe setuid scripts', or if suid-
perl is not installed, you are safe.
The exploit attempt reporting feature has been completely
removed from all the Perl 5.7 releases (and will be gone
also from the maintenance release 5.6.1), so that particular
vulnerability isn't there anymore. However, further security
vulnerabilities are, unfortunately, always possible. The
suidperl code is being reviewed and if deemed too risky to
continue to be supported, it may be completely removed from
future releases. In any case, suidperl should only be used
by security experts who know exactly what they are doing and
why they are using suidperl instead of some other solution
such as sudo ( see http://www.courtesan.com/sudo/ ).
+ Although "you shouldn't do that", it was possible to
write code that depends on Perl's hashed key order
(Data::Dumper does this). The new algorithm
"One-at-a-Time" produces a different hashed key order.
More details are in "Performance Enhancements".
+ The list of filenames from glob() (or <...>) is now by
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default sorted alphabetically to be csh-compliant.
(bsd_glob() does still sort platform natively, ASCII or
EBCDIC, unless GLOB_ALPHASORT is specified.)
AUTOLOAD Is Now Lvaluable
AUTOLOAD is now lvaluable, meaning that you can add the
:lvalue attribute to AUTOLOAD subroutines and you can assign
to the AUTOLOAD return value.
PerlIO is Now The Default
+ IO is now by default done via PerlIO rather than
system's "stdio". PerlIO allows "layers" to be "pushed"
onto a file handle to alter the handle's behaviour.
Layers can be specified at open time via 3-arg form of
open:
open($fh,'>:crlf :utf8', $path) || ...
or on already opened handles via extended "binmode":
binmode($fh,':encoding(iso-8859-7)');
The built-in layers are: unix (low level read/write),
stdio (as in previous Perls), perlio (re-implementation
of stdio buffering in a portable manner), crlf (does
CRLF <=> "\n" translation as on Win32, but available on
any platform). A mmap layer may be available if plat-
form supports it (mostly UNIXes).
Layers to be applied by default may be specified via the
'open' pragma.
See "Installation and Configuration Improvements" for
the effects of PerlIO on your architecture name.
+ File handles can be marked as accepting Perl's internal
encoding of Unicode (UTF-8 or UTF-EBCDIC depending on
platform) by a pseudo layer ":utf8" :
open($fh,">:utf8","Uni.txt");
Note for EBCDIC users: the pseudo layer ":utf8" is
erroneously named for you since it's not UTF-8 what you
will be getting but instead UTF-EBCDIC. See perlun-
icode, utf8, and
http://www.unicode.org/unicode/reports/tr16/ for more
information. In future releases this naming may change.
+ File handles can translate character encodings from/to
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Perl's internal Unicode form on read/write via the
":encoding()" layer.
+ File handles can be opened to "in memory" files held in
Perl scalars via:
open($fh,'>', \$variable) || ...
+ Anonymous temporary files are available without need to
'use FileHandle' or other module via
open($fh,"+>", undef) || ...
That is a literal undef, not an undefined value.
+ The list form of "open" is now implemented for pipes (at
least on UNIX):
open($fh,"-|", 'cat', '/etc/motd')
creates a pipe, and runs the equivalent of exec('cat',
'/etc/motd') in the child process.
+ The following builtin functions are now overridable:
chop(), chomp(), each(), keys(), pop(), push(), shift(),
splice(), unshift().
+ Formats now support zero-padded decimal fields.
+ Perl now tries internally to use integer values in
numeric conversions and basic arithmetics (+ - * /) if
the arguments are integers, and tries also to keep the
results stored internally as integers. This change leads
into often slightly faster and always less lossy arith-
metics. (Previously Perl always preferred floating point
numbers in its math.)
+ The printf() and sprintf() now support parameter reord-
ering using the "%\d+\$" and "*\d+\$" syntaxes. For
example
print "%2\$s %1\$s\n", "foo", "bar";
will print "bar foo\n"; This feature helps in writing
internationalised software.
+ Unicode in general should be now much more usable.
Unicode can be used in hash keys, Unicode in regular
expressions should work now, Unicode in tr/// should
work now (though tr/// seems to be a particularly tricky
to get right, so you have been warned)
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+ The Unicode Character Database coming with Perl has been
upgraded to Unicode 3.1. For more information, see
http://www.unicode.org/ , and
http://www.unicode.org/unicode/reports/tr27/
For developers interested in enhancing Perl's Unicode
capabilities: almost all the UCD files are included with
the Perl distribution in the lib/unicode subdirectory.
The most notable omission, for space considerations, is
the Unihan database.
+ The Unicode character classes \p{Blank} and
\p{SpacePerl} have been added. "Blank" is like C
isblank(), that is, it contains only "horizontal whi-
tespace" (the space character is, the newline isn't),
and the "SpacePerl" is the Unicode equivalent of "\s"
(\p{Space} isn't, since that includes the vertical tabu-
lator character, whereas "\s" doesn't.)
Signals Are Now Safe
Perl used to be fragile in that signals arriving at inoppor-
tune moments could corrupt Perl's internal state.
New Modules
+ B::Concise, by Stephen McCamant, is a new compiler back-
end for walking the Perl syntax tree, printing concise
info about ops. The output is highly customisable.
See B::Concise for more information.
+ Class::ISA, by Sean Burke, for reporting the search path
for a class's ISA tree, has been added.
See Class::ISA for more information.
+ Cwd has now a split personality: if possible, an exten-
sion is used, (this will hopefully be both faster and
more secure and robust) but if not possible, the fami-
liar Perl library implementation is used.
+ Digest, a frontend module for calculating digests
(checksums), from Gisle Aas, has been added.
See Digest for more information.
+ Digest::MD5 for calculating MD5 digests (checksums), by
Gisle Aas, has been added.
use Digest::MD5 'md5_hex';
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$digest = md5_hex("Thirsty Camel");
print $digest, "\n"; # 01d19d9d2045e005c3f1b80e8b164de1
NOTE: the MD5 backward compatibility module is deli-
berately not included since its use is discouraged.
See Digest::MD5 for more information.
+ Encode, by Nick Ing-Simmons, provides a mechanism to
translate between different character encodings. Sup-
port for Unicode, ISO-8859-*, ASCII, CP*, KOI8-R, and
three variants of EBCDIC are compiled in to the module.
Several other encodings (like Japanese, Chinese, and
MacIntosh encodings) are included and will be loaded at
runtime.
Any encoding supported by Encode module is also avail-
able to the ":encoding()" layer if PerlIO is used.
See Encode for more information.
+ Filter::Simple is an easy-to-use frontend to
Filter::Util::Call, from Damian Conway.
# in MyFilter.pm:
package MyFilter;
use Filter::Simple sub {
while (my ($from, $to) = splice @_, 0, 2) {
s/$from/$to/g;
}
};
1;
# in user's code:
use MyFilter qr/red/ => 'green';
print "red\n"; # this code is filtered, will print "green\n"
print "bored\n"; # this code is filtered, will print "bogreen\n"
no MyFilter;
print "red\n"; # this code is not filtered, will print "red\n"
See Filter::Simple for more information.
+ Filter::Util::Call, by Paul Marquess, provides you with
the framework to write Source Filters in Perl. For most
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uses the frontend Filter::Simple is to be preferred. See
Filter::Util::Call for more information.
+ Locale::Constants, Locale::Country, Locale::Currency,
and Locale::Language, from Neil Bowers, have been added.
They provide the codes for various locale standards,
such as "fr" for France, "usd" for US Dollar, and "jp"
for Japanese.
use Locale::Country;
$country = code2country('jp'); # $country gets 'Japan'
$code = country2code('Norway'); # $code gets 'no'
See Locale::Constants, Locale::Country,
Locale::Currency, and Locale::Language for more informa-
tion.
+ MIME::Base64, by Gisle Aas, allows you to encode data in
base64.
use MIME::Base64;
$encoded = encode_base64('Aladdin:open sesame');
$decoded = decode_base64($encoded);
print $encoded, "\n"; # "QWxhZGRpbjpvcGVuIHNlc2FtZQ=="
See MIME::Base64 for more information.
+ MIME::QuotedPrint, by Gisle Aas, allows you to encode
data in quoted-printable encoding.
use MIME::QuotedPrint;
$encoded = encode_qp("Smiley in Unicode: \x{263a}");
$decoded = decode_qp($encoded);
print $encoded, "\n"; # "Smiley in Unicode: =263A"
MIME::QuotedPrint has been enhanced to provide the basic
methods necessary to use it with PerlIO::Via as in :
use MIME::QuotedPrint;
open($fh,">Via(MIME::QuotedPrint)",$path)
See MIME::QuotedPrint for more information.
+ PerlIO::Scalar, by Nick Ing-Simmons, provides the imple-
mentation of IO to "in memory" Perl scalars as discussed
above. It also serves as an example of a loadable
layer. Other future possibilities include PerlIO::Array
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and PerlIO::Code. See PerlIO::Scalar for more informa-
tion.
+ PerlIO::Via, by Nick Ing-Simmons, acts as a PerlIO layer
and wraps PerlIO layer functionality provided by a class
(typically implemented in perl code).
use MIME::QuotedPrint;
open($fh,">Via(MIME::QuotedPrint)",$path)
This will automatically convert everything output to $fh
to Quoted-Printable. See PerlIO::Via for more informa-
tion.
+ Pod::Text::Overstrike, by Joe Smith, has been added. It
converts POD data to formatted overstrike text. See
Pod::Text::Overstrike for more information.
+ Switch from Damian Conway has been added. Just by say-
ing
use Switch;
you have "switch" and "case" available in Perl.
use Switch;
switch ($val) {
case 1 { print "number 1" }
case "a" { print "string a" }
case [1..10,42] { print "number in list" }
case (@array) { print "number in list" }
case /\w+/ { print "pattern" }
case qr/\w+/ { print "pattern" }
case (%hash) { print "entry in hash" }
case (\%hash) { print "entry in hash" }
case (\&sub) { print "arg to subroutine" }
else { print "previous case not true" }
}
See Switch for more information.
+ Text::Balanced from Damian Conway has been added, for
extracting delimited text sequences from strings.
use Text::Balanced 'extract_delimited';
($a, $b) = extract_delimited("'never say never', he never said", "'", '');
$a will be "'never say never'", $b will be ', he never
said'.
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In addition to extract_delimited() there are also
extract_bracketed(), extract_quotelike(),
extract_codeblock(), extract_variable(),
extract_tagged(), extract_multiple(),
gen_delimited_pat(), and gen_extract_tagged(). With
these you can implement rather advanced parsing algo-
rithms. See Text::Balanced for more information.
+ Tie::RefHash::Nestable, by Edward Avis, allows storing
hash references (unlike the standard Tie::RefHash) The
module is contained within Tie::RefHash.
+ XS::Typemap, by Tim Jenness, is a test extension that
exercises XS typemaps. Nothing gets installed but for
extension writers the code is worth studying.
Updated And Improved Modules and Pragmata
+ B::Deparse should be now more robust. It still far from
providing a full round trip for any random piece of Perl
code, though, and is under active development: expect
more robustness in 5.7.2.
+ Class::Struct can now define the classes in compile
time.
+ Math::BigFloat has undergone much fixing, and in addi-
tion the fmod() function now supports modulus opera-
tions.
( The fixed Math::BigFloat module is also available in
CPAN for those who can't upgrade their Perl:
http://www.cpan.org/authors/id/J/JP/JPEACOCK/ )
+ Devel::Peek now has an interface for the Perl memory
statistics (this works only if you are using perl's mal-
loc, and if you have compiled with debugging).
+ IO::Socket has now atmark() method, which returns true
if the socket is positioned at the out-of-band mark.
The method is also exportable as a sockatmark() func-
tion.
+ IO::Socket::INET has support for ReusePort option (if
your platform supports it). The Reuse option now has an
alias, ReuseAddr. For clarity you may want to prefer
ReuseAddr.
+ Net::Ping has been enhanced. There is now "external"
protocol which uses Net::Ping::External module which
runs external ping(1) and parses the output. An alpha
version of Net::Ping::External is available in CPAN and
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in 5.7.2 the Net::Ping::External may be integrated to
Perl.
+ The "open" pragma allows layers other than ":raw" and
":crlf" when using PerlIO.
+ POSIX::sigaction() is now much more flexible and robust.
You can now install coderef handlers, 'DEFAULT', and
'IGNORE' handlers, installing new handlers was not
atomic.
+ The Test module has been significantly enhanced. Its
use is greatly recommended for module writers.
+ The utf8:: name space (as in the pragma) provides vari-
ous Perl-callable functions to provide low level access
to Perl's internal Unicode representation. At the
moment only length() has been implemented.
The following modules have been upgraded from the versions
at CPAN: CPAN, CGI, DB_File, File::Temp, Getopt::Long,
Pod::Man, Pod::Text, Storable, Text-Tabs+Wrap.
+ Hashes now use Bob Jenkins "One-at-a-Time" hashing key
algorithm ( http://burtleburtle.net/bob/hash/doobs.html
). This algorithm is reasonably fast while producing a
much better spread of values than the old hashing algo-
rithm (originally by Chris Torek, later tweaked by Ilya
Zakharevich). Hash values output from the algorithm on
a hash of all 3-char printable ASCII keys comes much
closer to passing the DIEHARD random number generation
tests. According to perlbench, this change has not
affected the overall speed of Perl.
+ unshift() should now be noticeably faster.
+ h2xs now produces template README.
+ s2p has been completely rewritten in Perl. (It is in
fact a full implementation of sed in Perl.)
+ xsubpp now supports OUT keyword.
perlclib
Internal replacements for standard C library functions.
(Interesting only for extension writers and Perl core hack-
ers.)
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perliol
Internals of PerlIO with layers.
README.aix
Documentation on compiling Perl on AIX has been added. AIX
has several different C compilers and getting the right
patch level is essential. On install README.aix will be
installed as perlaix.
README.bs2000
Documentation on compiling Perl on the POSIX-BC platform (an
EBCDIC mainframe environment) has been added.
This was formerly known as README.posix-bc but the name was
considered to be too confusing (it has nothing to do with
the POSIX module or the POSIX standard). On install
README.bs2000 will be installed as perlbs2000.
README.macos
In perl 5.7.1 (and in the 5.6.1) the MacPerl sources have
been synchronised with the standard Perl sources. To com-
pile MacPerl some additional steps are required, and this
file documents those steps. On install README.macos will be
installed as perlmacos.
README.mpeix
The README.mpeix has been podified, which means that this
information about compiling and using Perl on the MPE/iX
miniframe platform will be installed as perlmpeix.
README.solaris
README.solaris has been created and Solaris wisdom from
elsewhere in the Perl documentation has been collected
there. On install README.solaris will be installed as perl-
solaris.
README.vos
The README.vos has been podified, which means that this
information about compiling and using Perl on the Stratus
VOS miniframe platform will be installed as perlvos.
Porting/repository.pod
Documentation on how to use the Perl source repository has
been added.
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+ Because PerlIO is now the default on most platforms,
"-perlio" doesn't get appended to the $Config{archname}
(also known as $^O) anymore. Instead, if you explicitly
choose not to use perlio (Configure command line option
-Uuseperlio), you will get "-stdio" appended.
+ Another change related to the architecture name is that
"-64all" (-Duse64bitall, or "maximally 64-bit") is
appended only if your pointers are 64 bits wide. (To be
exact, the use64bitall is ignored.)
+ APPLLIB_EXP, a less-know configuration-time definition,
has been documented. It can be used to prepend site-
specific directories to Perl's default search path
(@INC), see INSTALL for information.
+ Building Berkeley DB3 for compatibility modes for DB,
NDBM, and ODBM has been documented in INSTALL.
+ If you are on IRIX or Tru64 platforms, new
profiling/debugging options have been added, see
perlhack for more information about pixie and Third
Degree.
New Or Improved Platforms
For the list of platforms known to support Perl, see "Sup-
ported Platforms" in perlport.
+ AIX dynamic loading should be now better supported.
+ After a long pause, AmigaOS has been verified to be
happy with Perl.
+ EBCDIC platforms (z/OS, also known as OS/390, POSIX-BC,
and VM/ESA) have been regained. Many test suite tests
still fail and the co-existence of Unicode and EBCDIC
isn't quite settled, but the situation is much better
than with Perl 5.6. See perlos390, perlbs2000 (for
POSIX-BC), and perlvmesa for more information.
+ Building perl with -Duseithreads or -Duse5005threads now
works under HP-UX 10.20 (previously it only worked under
10.30 or later). You will need a thread library package
installed. See README.hpux.
+ Mac OS Classic (MacPerl has of course been available
since perl 5.004 but now the source code bases of stan-
dard Perl and MacPerl have been synchronised)
+ NCR MP-RAS is now supported.
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+ NonStop-UX is now supported.
+ Amdahl UTS is now supported.
+ z/OS (formerly known as OS/390, formerly known as MVS
OE) has now support for dynamic loading. This is not
selected by default, however, you must specify -Dusedl
in the arguments of Configure.
Generic Improvements
+ Configure no longer includes the DBM libraries (dbm,
gdbm, db, ndbm) when building the Perl binary. The only
exception to this is SunOS 4.x, which needs them.
+ Some new Configure symbols, useful for extension writ-
ers:
d_cmsghdr
For struct cmsghdr.
d_fcntl_can_lock
Whether fcntl() can be used for file locking.
d_fsync
d_getitimer
d_getpagsz
For getpagesize(), though you should prefer
POSIX::sysconf(_SC_PAGE_SIZE))
d_msghdr_s
For struct msghdr.
need_va_copy
Whether one needs to use Perl_va_copy() to copy
varargs.
d_readv
d_recvmsg
d_sendmsg
sig_size
The number of elements in an array needed to
hold all the available signals.
d_sockatmark
d_strtoq
d_u32align
Whether one needs to access character data
aligned by U32 sized pointers.
d_ualarm
d_usleep
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+ Removed Configure symbols: the PDP-11 memory model set-
tings: huge, large, medium, models.
+ SOCKS support is now much more robust.
+ If your filesystem supports symbolic links you can build
Perl outside of the source directory by
mkdir perl/build/directory
cd perl/build/directory
sh /path/to/perl/source/Configure -Dmksymlinks ...
This will create in perl/build/directory a tree of sym-
bolic links pointing to files in /path/to/perl/source.
The original files are left unaffected. After Configure
has finished you can just say
make all test
and Perl will be built and tested, all in
perl/build/directory.
Numerous memory leaks and uninitialized memory accesses have
been hunted down. Most importantly anonymous subs used to
leak quite a bit.
+ chop(@list) in list context returned the characters
chopped in reverse order. This has been reversed to be
in the right order.
+ The order of DESTROYs has been made more predictable.
+ mkdir() now ignores trailing slashes in the directory
name, as mandated by POSIX.
+ Attributes (like :shared) didn't work with our().
+ The PERL5OPT environment variable (for passing command
line arguments to Perl) didn't work for more than a sin-
gle group of options.
+ The tainting behaviour of sprintf() has been rational-
ized. It does not taint the result of floating point
formats anymore, making the behaviour consistent with
that of string interpolation.
+ All but the first argument of the IO syswrite() method
are now optional.
+ Tie::ARRAY SPLICE method was broken.
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+ vec() now tries to work with characters <= 255 when pos-
sible, but it leaves higher character values in place.
In that case, if vec() was used to modify the string, it
is no longer considered to be utf8-encoded.
Platform Specific Changes and Fixes
+ Linux previously had problems related to sockaddrlen
when using accept(), revcfrom() (in Perl: recv()), get-
peername(), and getsockname().
+ Previously DYNIX/ptx had problems in its Configure probe
for non-blocking I/O.
+ Windows
+ Borland C++ v5.5 is now a supported compiler
that can build Perl. However, the generated
binaries continue to be incompatible with those
generated by the other supported compilers (GCC
and Visual C++).
+ Win32::GetCwd() correctly returns C:\ instead of
C: when at the drive root. Other bugs in chdir()
and Cwd::cwd() have also been fixed.
+ Duping socket handles with open(F, ">&MYSOCK")
now works under Windows 9x.
+ HTML files will be installed in c:\perl\html
instead of c:\perl\lib\pod\html
+ The makefiles now provide a single switch to
bulk-enable all the features enabled in Active-
State ActivePerl (a popular binary distribu-
tion).
Two new debugging options have been added: if you have com-
piled your Perl with debugging, you can use the -DT and -DR
options to trace tokenising and to add reference counts to
displaying variables, respectively.
+ If an attempt to use a (non-blessed) reference as an
array index is made, a warning is given.
+ "push @a;" and "unshift @a;" (with no values to push or
unshift) now give a warning. This may be a problem for
generated and evaled code.
+ Some new APIs: ptr_table_clear(), ptr_table_free(),
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sv_setref_uv(). For the full list of the available APIs
see perlapi.
+ dTHR and djSP have been obsoleted; the former removed
(because it's a no-op) and the latter replaced with dSP.
+ Perl now uses system malloc instead of Perl malloc on
all 64-bit platforms, and even in some not-always-64-bit
platforms like AIX, IRIX, and Solaris. This change
breaks backward compatibility but Perl's malloc has
problems with large address spaces and also the speed of
vendors' malloc is generally better in large address
space machines (Perl's malloc is mostly tuned for
space).
Many new tests have been added. The most notable is prob-
ably the lib/1_compile: it is very notable because running
it takes quite a long time -- it test compiles all the Perl
modules in the distribution. Please be patient.
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 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.
lib/ftmp-security tests warn 'system possibly insecure'
Don't panic. Read INSTALL 'make test' section instead.
lib/io_multihomed Fails In LP64-Configured HP-UX
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 con-
nect to "multihomed" sockets (sockets which have multiple IP
addresses).
Test lib/posix Subtest 9 Fails In LP64-Configured HP-UX
If perl is configured with -Duse64bitall, the successful
result of the subtest 10 of lib/posix may arrive before the
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successful result of the subtest 9, which confuses the test
harness so much that it thinks the subtest 9 failed.
lib/b test 19
The test fails on various platforms (PA64 and IA64 are
known), but the exact cause is still being investigated.
Linux With Sfio Fails op/misc Test 48
No known fix.
sigaction test 13 in VMS
The test is known to fail; whether it's because of VMS of
because of faulty test is not known.
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 else
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
The subtests 19 and 20 of lib/thr5005.t test 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. (Note that
support for 5.005-style threading remains experimental.)
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
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dumps, most often) it is for now forbidden (you will get a
fatal error even from an attempt).
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.
If you find what you think is a bug, you might check the
articles recently posted to the comp.lang.perl.misc news-
group 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.
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.
Written by Jarkko Hietaniemi <jhi@iki.fi>, with many contri-
butions from The Perl Porters and Perl Users submitting
feedback and patches.
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Send omissions or corrections to <perlbug@perl.org>.
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