5.7.1 release.
(To view the differences between the 5.6.0 release and the 5.7.0
-release, see L<perl570delta>).
+release, see L<perl570delta>.)
=head1 Security Vulnerability Closed
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/).
+suidperl instead of some other solution such as sudo
+( see http://www.courtesan.com/sudo/ ).
=head1 Incompatible Changes
=head1 Core Enhancements
-=over 4
-
-=item *
+=head2 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.
+=head2 PerlIO is Now The Default
+
+=over 4
+
=item *
IO is now by default done via PerlIO rather than system's "stdio".
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
-platform supports it (mostly UNIXes).
+platform supports it (mostly Unixes).
Layers to be applied by default may be specified via the 'open' pragma.
open($fh,">:utf8","Uni.txt");
-Note for EBCDIC users: the pseudo layer ":utf8" is badly named for you
-since it's not UTF-8 what you will be getting but instead UTF-EBCDIC.
-See http://www.unicode.org/unicode/reports/tr16/ for more information.
-In future release this naming issue may or may not change.
+Note for EBCDIC users: the pseudo layer ":utf8" is erroneously named
+for you since it's not UTF-8 what you will be getting but instead
+UTF-EBCDIC. See L<perlunicode>, L<utf8>, and
+http://www.unicode.org/unicode/reports/tr16/ for more information.
+In future releases this naming may change.
=item *
=item *
-The list form of C<open> is now implemented for pipes (at least on UNIX):
+The list form of C<open> is now implemented for pipes (at least on Unix):
open($fh,"-|", 'cat', '/etc/motd')
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
-arithmetics (previously Perl always preferred floating point numbers
-in its math)
+arithmetics. (Previously Perl always preferred floating point numbers
+in its math.)
=item *
=item *
The Unicode Character Database coming with Perl has been upgraded
-to Unicode 3.1. For more information, see http://www.unicode.org/,
+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:
=back
+=head2 Signals Are Now Safe
+
+Perl used to be fragile in that signals arriving at inopportune moments
+could corrupt Perl's internal state.
+
=head1 Modules and Pragmata
=head2 New Modules
=item *
-B::Concise, from Stephen McCamant, is a new compiler backend for
+B::Concise, by Stephen McCamant, is a new compiler backend for
walking the Perl syntax tree, printing concise info about ops.
The output is highly customisable.
=item *
-Class::ISA for reporting the search path for a class's ISA tree,
-from Sean Burke, has been added.
+Class::ISA, by Sean Burke, for reporting the search path for a
+class's ISA tree, has been added.
See L<Class::ISA> for more information.
=item *
-Digest::MD5 for calculating MD5 digests (checksums), from Gisle Aas,
+Digest::MD5 for calculating MD5 digests (checksums), by Gisle Aas,
has been added.
use Digest::MD5 'md5_hex';
print $digest, "\n"; # 01d19d9d2045e005c3f1b80e8b164de1
-NOTE: the MD5 backward compatibility module is purposefully not
+NOTE: the MD5 backward compatibility module is deliberately not
included since its use is discouraged.
See L<Digest::MD5> for more information.
=item *
-Encode, from Nick Ing-Simmons, provides a mechanism to translate
+Encode, by Nick Ing-Simmons, provides a mechanism to translate
between different character encodings. Support for Unicode,
ISO-8859-*, ASCII, CP*, KOI8-R, and three variants of EBCDIC are
compiled in to the module. Several other encodings (like Japanese,
=item *
-Filter::Util::Call, from Paul Marquess, provides you with the
+Filter::Util::Call, by Paul Marquess, provides you with the
framework to write I<Source Filters> in Perl. For most uses
the frontend Filter::Simple is to be preferred.
See L<Filter::Util::Call> for more information.
=item *
-MIME::Base64, from Gisle Aas, allows you to encode data in base64.
+MIME::Base64, by Gisle Aas, allows you to encode data in base64.
use MIME::Base64;
=item *
-MIME::QuotedPrint, from Gisle Aas, allows you to encode data in
+MIME::QuotedPrint, by Gisle Aas, allows you to encode data in
quoted-printable encoding.
use MIME::QuotedPrint;
=item *
-PerlIO::Scalar, from Nick Ing-Simmons, provides the implementation of
+PerlIO::scalar, by Nick Ing-Simmons, provides the implementation of
IO to "in memory" Perl scalars as discussed above. It also serves as
an example of a loadable layer. Other future possibilities include
-PerlIO::Array and PerlIO::Code. See L<PerlIO::Scalar> for more
+PerlIO::array and PerlIO::code. See L<PerlIO::scalar> for more
information.
=item *
-PerlIO::Via, from Nick Ing-Simmons, acts as a PerlIO layer and wraps
+PerlIO::Via, by Nick Ing-Simmons, acts as a PerlIO layer and wraps
PerlIO layer functionality provided by a class (typically implemented
in perl code).
open($fh,">Via(MIME::QuotedPrint)",$path)
This will automatically convert everything output to C<$fh>
-to Quoted-Printable. See L<PerlIO::Via> for more information.
+to Quoted-Printable. See L<PerlIO::via> for more information.
=item *
-Pod::Text::Overstrike, from Joe Smith, has been added.
+Pod::Text::Overstrike, by Joe Smith, has been added.
It converts POD data to formatted overstrike text.
See L<Pod::Text::Overstrike> for more information.
($a, $b) = extract_delimited("'never say never', he never said", "'", '');
-C<$a> will be "'never say never'", C<$b> will be ', he never said'.
+$a will be "'never say never'", $b will be ', he never said'.
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(). See L<Text::Balanced> for more information.
+gen_extract_tagged(). With these you can implement rather advanced
+parsing algorithms. See L<Text::Balanced> for more information.
=item *
-Tie::RefHash::Nestable, from Edward Avis, allows storing hash references
-(unlike the standard Tie::Refhash) The module is contained within
+Tie::RefHash::Nestable, by Edward Avis, allows storing hash references
+(unlike the standard Tie::RefHash) The module is contained within
Tie::RefHash.
=item *
-XS::Typemap is a test extension that exercises XS typemaps.
-Nothing gets installed but for extension writers the code is
-worth studying.
+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.
=back
Math::BigFloat has undergone much fixing, and in addition the fmod()
function now supports modulus operations.
-(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/)
+( 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/ )
=item *
=back
The following modules have been upgraded from the versions at CPAN:
-CPAN, CGI, DB::File, File::Temp, Getopt::Long, Pod::Man, Pod::Text,
+CPAN, CGI, DB_File, File::Temp, Getopt::Long, Pod::Man, Pod::Text,
Storable, Text-Tabs+Wrap.
=head1 Performance Enhancements
=item *
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. 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.
+( http://burtleburtle.net/bob/hash/doobs.html ). This algorithm is
+reasonably fast while producing a much better spread of values than
+the old hashing algorithm (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.
=item *
=item *
-In HP-UX 10.20 Perl threading is now working with the various threading
-packages available for HP-UX. See L<perlhpux> (or in the source
-distribution, README.hpux) 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.
=item *
-MacOS Classic (MacPerl has of course been available since
+Mac OS Classic (MacPerl has of course been available since
perl 5.004 but now the source code bases of standard Perl
and MacPerl have been synchronised)
If your file system supports symbolic links you can build Perl outside
of the source directory by
- mkdir /tmp/perl/build/directory
- cd /tmp/perl/build/directory
+ mkdir perl/build/directory
+ cd perl/build/directory
sh /path/to/perl/source/Configure -Dmksymlinks ...
-This will create in /tmp/perl/build/directory a tree of symbolic links
+This will create in perl/build/directory a tree of symbolic 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 /tmp/perl/build/directory.
+and Perl will be built and tested, all in perl/build/directory.
=back
=head1 Selected Bug Fixes
-Numerous memory leaks and uninitialized memory leaks have been hunted down.
+Numerous memory leaks and uninitialized memory accesses have been hunted down.
Most importantly anonymous subs used to leak quite a bit.
=over 4
=item *
-chop(@list) in list context returned the characters chopped in reverse
-order. This has been reversed to be in the right order.
+chop(@list) in list context returned the characters chopped in
+reverse order. This has been reversed to be in the right order.
=item *
-The order of DESTROYS has been made more predictable.
+The order of DESTROYs has been made more predictable.
=item *
=item *
+HTML files will be installed in c:\perl\html instead of c:\perl\lib\pod\html
+
+=item *
+
The makefiles now provide a single switch to bulk-enable all the features
enabled in ActiveState ActivePerl (a popular binary distribution).
=item *
-If an attempt to use a (non-blessed) reference as an array element
+If an attempt to use a (non-blessed) reference as an array index
is made, a warning is given.
=item *
C<push @a;> and C<unshift @a;> (with no values to push or unshift)
-now give a warning. This may be a problem for generated and evaled
+now give a warning. This may be a problem for generated and eval'ed
code.
=back
=item *
-Perl now uses system malloc instead of Perl malloc in all 64-bit
+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
=back
+=head1 New Tests
+
+Many new tests have been added. The most notable is probably 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.
+
=head1 Known Problems
-Notice that this list doesn't contain problems that were present in
-5.7.0 and still are there, see L<perl570delta> for those.
+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.
-=head2 lib/b test 19
+=head2 AIX vac 5.0.0.0 May Produce Buggy Code For Perl
-The test fails in various platforms (PA64 and IA64 are known), but the
-exact cause is still being investigated.
+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.
-=head2 Localising a Tied Variable Leaks Memory
+=head2 lib/ftmp-security tests warn 'system possibly insecure'
- use Tie::Hash;
- tie my %tie_hash => 'Tie::StdHash';
+Don't panic. Read INSTALL 'make test' section instead.
- ...
+=head2 lib/io_multihomed Fails In LP64-Configured HP-UX
- local($tie_hash{Foo}) = 1; # leaks
+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).
-Code like the above is known to leak memory every time the local()
-is executed.
+=head2 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 successful result of the
+subtest 9, which confuses the test harness so much that it thinks the
+subtest 9 failed.
+
+=head2 lib/b test 19
+
+The test fails on various platforms (PA64 and IA64 are known), but the
+exact cause is still being investigated.
+
+=head2 Linux With Sfio Fails op/misc Test 48
+
+No known fix.
=head2 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.
+The test is known to fail; whether it's because of VMS of because
+of faulty test is not known.
=head2 sprintf tests 129 and 130
-The op/sprintf tests 129 and 130 are known to fail in some platforms.
-Examples include any platform using sfio, and Tandem's NonStop-UX.
+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".)
+=head2 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.)
+
+=head2 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.
+
=head2 Self-tying of Arrays and Hashes Is Forbidden
Self-tying of arrays and hashes is broken in rather deep and
frustrated at the mysterious results (core dumps, most often) it is
for now forbidden (you will get a fatal error even from an attempt).
+=head2 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.
+
+=head2 The Compiler Suite Is Still Experimental
+
+The compiler suite is slowly getting better but is nowhere near
+working order yet.
+
=head1 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.
+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 B<perlbug>
program included with your release. Be sure to trim your bug down
https://perl5.git.perl.org / perl5.git / blobdiff