=head1 DESCRIPTION
-This document describes differences between the 5.6.0 release and the
-5.8.0 release.
+This document describes differences between the 5.6.0 release
+and the 5.8.0 release.
-=head1 Highlights
+Many of the bug fixes in 5.8.0 were already seen in the 5.6.1
+maintenance release since the two releases were kept closely
+coordinated.
+
+If you are upgrading from Perl 5.005_03, you might also want
+to read L<perl56delta>.
+
+=head1 Highlights In 5.8.0
=over 4
modules. The change was made to make Perl more compliant with other
applications like modperl which are using the AIX native interface.
+=head2 Attributes for C<my> variables now handled at run-time.
+
+The C<my EXPR : ATTRS> syntax now applies variable attributes at
+run-time. (Subroutine and C<our> variables still get attributes applied
+at compile-time.) See L<attributes> for additional details. In particular,
+however, this allows variable attributes to be useful for C<tie> interfaces,
+which was a deficiency of earlier releases. Note that the new semantics
+doesn't work with the Attribute::Handlers module (as of version 0.76).
+
=head2 Socket Extension Dynamic in VMS
The Socket extension is now dynamically loaded instead of being
TCP/IP stacks of VMS: we do not know since we weren't able to test
Perl in such configurations.
+=head2 IEEE-format Floating Point Default on OpenVMS Alpha
+
+Perl now uses IEEE format (T_FLOAT) as the default internal floating
+point format on OpenVMS Alpha, potentially breaking binary compatibility
+with external libraries or existing data. G_FLOAT is still available as
+a configuration option. The default on VAX (D_FLOAT) has not changed.
+
=head2 Different Definition of the Unicode Character Classes \p{In...}
As suggested by the Unicode consortium, the Unicode character classes
=item *
The list of filenames from glob() (or <...>) is now by default sorted
-alphabetically to be csh-compliant. (bsd_glob() does still sort platform
+alphabetically to be csh-compliant (which is what happened before
+in most UNIX platforms). (bsd_glob() does still sort platform
natively, ASCII or EBCDIC, unless GLOB_ALPHASORT is specified.)
=item *
+Spurious syntax errors generated in certain situations, when glob()
+caused File::Glob to be loaded for the first time, have been fixed.
+
+=item *
+
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.
=back
-=head2 Signals Are Now Safe
+=head2 Safe Signals
Perl used to be fragile in that signals arriving at inopportune moments
could corrupt Perl's internal state. Now Perl postpones handling of
-signals until it's safe.
+signals until it's safe (between opcodes).
+
+This change may have surprising side effects because signals no more
+interrupt Perl instantly. Perl will now first finish whatever it was
+doing, like finishing an internal operation (like sort()) or an
+external operation (like an I/O operation), and only then look at any
+arrived signals (and before starting the next operation). No more corrupt
+internal state since the current operation is always finished first,
+but the signal may take more time to get heard.
=head2 Unicode Overhaul
=item *
Lvalue subroutines can now return C<undef> in list context.
+However, the lvalue subroutine feature still remains experimental.
=item *
=item *
-UNTIE method is now recognised.
+untie() will now call an UNTIE() hook if it exists. See L<perltie>
+for details.
=item *
=item *
C<Pod::ParseLink>, by Russ Allbery, has been added,
-to parse L<> links in pods as described in the new
+to parse LZ<><> links in pods as described in the new
perlpodspec.
=item *
=item *
+DB_File now supports newer Berkeley DB versions, among
+other improvements.
+
+=item *
+
The English module can now be used without the infamous performance
hit by saying
=item *
+File::Find now chdir()s correctly when chasing symbolic links.
+
+=item *
+
File::Find now has pre- and post-processing callbacks. It also
correctly changes directories when chasing symbolic links. Callbacks
(naughtily) exiting with "next;" instead of "return;" now work.
=item *
+Math::Complex handles inf, NaN etc., better.
+
+=item *
+
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 in 5.7.2 the Net::Ping::External may be integrated to Perl.
+the output. A version of Net::Ping::External is available in CPAN.
=item *
=item *
+In SDBM_File on dosish platforms, some keys went missing because of
+lack of support for files with "holes". A workaround for the problem
+has been added.
+
+=item *
+
In Search::Dict one can now have a pre-processing hook for the
lines being searched.
C<perlcc> has been rewritten and its user interface (that is,
command line) is much more like that of the UNIX C compiler, cc.
+(The perlbc tools has been removed. Use C<perlcc -B> instead.)
=item *
=item *
-map() that changes the size of the list should now work faster.
+map() could get pathologically slow when the result list it generates
+is larger than the source list. The performance has been improved for
+common scenarios.
=item *
=item *
+Configure support for pdp11-style memory models has been removed due
+to obsolescence.
+
+=item *
+
configure.gnu now works with options with whitespace in them.
=item *
=item *
+NEC SUPER-UX is now supported.
+
+=item *
+
Amdahl UTS UNIX mainframe platform is now supported.
=item *
=item *
+caller() could cause core dumps in certain situations. Carp was sometimes
+affected by this problem.
+
+=item *
+
chop(@list) in list context returned the characters chopped in
reverse order. This has been reversed to be in the right order.
Several debugger fixes: exit code now reflects the script exit code,
condition C<"0"> now treated correctly, the C<d> command now checks
-line number, the C<$.> no longer gets corrupted, all debugger output now
-goes correctly to the socket if RemotePort is set.
+line number, the C<$.> no longer gets corrupted, all debugger output
+now goes correctly to the socket if RemotePort is set.
+
+=item *
+
+Perl 5.6.0 could emit spurious warnings about redefinition of dl_error()
+when statically building extensions into perl. This has been corrected.
=item *
=item *
C<*foo{FORMAT}> now works.
+=item *
+
+Infinity is now recognized as a number.
=item *
=item *
-Lexical warnings now propagating correctly between scopes.
+Lexical warnings now propagating correctly between scopes
+and into C<eval "...">.
+
+=item *
+
+C<use warnings qw(FATAL all)> did not work as intended. This has been
+corrected.
+
+=item *
+
+warnings::enabled() now reports the state of $^W correctly if the caller
+isn't using lexical warnings.
=item *
=item *
+Numeric conversions did not recognize changes in the string value
+properly in certain circumstances.
+
+=item *
+
Attributes (like :shared) didn't work with our().
=item *
=item *
+"our" variables of the same name declared in two sibling blocks
+resulted in bogus warnings about "redeclaration" of the variables.
+The problem has been corrected.
+
+=item *
+
pack "Z" now correctly terminates the string with "\0".
=item *
=item *
-C<q(a\\b)> now parses correctly as C<'a\\b'>.
+C<qw(a\\b)> now parses correctly as C<'a\\b'>.
+
+=item *
+
+pos() did not return the correct value within s///ge in earlier
+versions. This is now handled correctly.
=item *
sort() arguments are now compiled in the right wantarray context
(they were accidentally using the context of the sort() itself).
+The comparison block is now run in scalar context, and the arguments
+to be sorted are always provided list context.
=item *
=item *
+Some cases of inconsistent taint propagation (such as within hash
+values) have been fixed.
+
+=item *
+
+The RE engine found in Perl 5.6.0 accidentally pessimised certain kinds
+of simple pattern matches. These are now handled better.
+
+=item *
+
+Regular expression debug output (whether through C<use re 'debug'>
+or via C<-Dr>) now looks better.
+
+=item *
+
+Multi-line matches like C<"a\nxb\n" =~ /(?!\A)x/m> were flawed. The
+bug has been fixed.
+
+=item *
+
+Use of $& could trigger a core dump under some situations. This
+is now avoided.
+
+=item *
+
The regular expression captured submatches ($1, $2, ...) are now
more consistently unset if the match fails, instead of leaving false
data lying around in them.
=item *
+readline() on files opened in "slurp" mode could return an extra "" at
+the end in certain situations. This has been corrected.
+
+=item *
+
+Autovivification of symbolic references of special variables described
+in L<perlvar> (as in C<${$num}>) was accidentally disabled. This works
+again now.
+
+=item *
+
Sys::Syslog ignored the C<LOG_AUTH> constant.
=item *
=item *
+Perl 5.6.0 parsed m/\x{ab}/ incorrectly, leading to spurious warnings.
+This has been corrected.
+
+=item *
+
Zero entries were missing from the Unicode classes like C<IsDigit>.
=back
+=item *
+
+Large unsigned numbers (those above 2**31) could sometimes lose their
+unsignedness, causing bogus results in arithmetic operations.
+
=back
=head2 Platform Specific Changes and Fixes
chdir() now works better despite a CRT bug; now works with MULTIPLICITY
(see INSTALL); now works with Perl's malloc.
+The tainting of C<%ENV> elements via C<keys> or C<values> was previously
+unimplemented. It now works as documented.
+
+The C<waitpid> emulation has been improved. The worst bug (now fixed)
+was that a pid of -1 would cause a wildcard search of all processes on
+the system. The most significant enhancement is that we can now
+usually get the completion status of a terminated process.
+
+POSIX-style signals are now emulated much better on VMS versions prior
+to 7.0.
+
+The C<system> function and backticks operator have improved
+functionality and better error handling.
+
=item *
Windows
=item *
+Current directory entries in %ENV are now correctly propagated to child
+processes.
+
+=item *
+
$ENV{LIB} now used to search for libs under Visual C.
=item *
-Win32::GetCwd() correctly returns C:\ instead of C: when at the drive root.
-Other bugs in chdir() and Cwd::cwd() have also been fixed.
+fork() emulation has been improved in various ways, but still continues
+to be experimental. See L<perlfork> for known bugs and caveats.
=item *
=item *
+Win32::GetCwd() correctly returns C:\ instead of C: when at the drive root.
+Other bugs in chdir() and Cwd::cwd() have also been fixed.
+
+=item *
+
HTML files will be installed in c:\perl\html instead of c:\perl\lib\pod\html
=item *
=item *
+%SIG has been enabled under USE_ITHREADS, but its use is completely
+unsupported under all configurations.
+
+=item *
+
Less stack reserved per thread so that more threads can run
concurrently. (Still 16M per thread.)
=item *
-wait() and waitpid() now work much better.
+wait(), waitpid() and backticks now return the correct exit status under
+Windows 9x.
=item *
=item *
-Now xsubs can have attributes just like subs.
+Now xsubs can have attributes just like subs. (Well, at least the
+built-in attributes.)
=item *
No known fix.
+=head2 Mac OS X
+
+The following tests are known to fail:
+
+ Failed Test Stat Wstat Total Fail Failed List of Failed
+ -------------------------------------------------------------------------
+ ../ext/DB_File/t/db-btree.t 0 11 ?? ?? % ??
+ ../ext/DB_File/t/db-recno.t 149 3 2.01% 61 63 65
+ ../ext/POSIX/t/posix.t 31 1 3.23% 10
+ ../lib/warnings.t 450 1 0.22% 316
+
=head2 OS/390
OS/390 has rather many test failures but the situation is actually
=head2 Failure of Thread tests
-B<Note that support for 5.005-style threading remains experimental.>
+B<Note that support for 5.005-style threading remains experimental
+and practically unsupported.>
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
+ ext/List/Util/t/first 2
+ lib/autouse 4
+ ext/Thread/thr5005 19-20
+
+These failures are unlikely to get fixed.
=head2 UNICOS
=head2 VMS
-Rather a lot of tests are failing in VMS, but 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.
-
-Compaq C V6.2-009 on OpenVMS Alpha V7.3
+There is one known test failure with a default configuration:
[.run]switches..........................FAILED on test 1
- [-.ext.posix.t]posix....................FAILED on test 10
- [-.ext.time.hires]hires.................FAILED on test 17
- [-.lib]db...............................FAILED on test 24
- [-.lib.net]hostent......................FAILED on test 5
- [-.lib.pod.t]basic......................FAILED on test 10
=head2 Win32
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 Variable Attributes are not Currently Usable for Tieing
-
-This limitation will hopefully be fixed in future. (Subroutine
-attributes work fine for tieing, see L<Attribute::Handlers>).
-
-One way to run into this limitation is to have a loop variable with
-attributes within a loop: the tie is called only once, not for each
-iteration of the loop.
-
=head2 Building Extensions Can Fail Because Of Largefiles
Some extensions like mod_perl are known to have issues with
=head2 The Compiler Suite Is Still Experimental
-The compiler suite is slowly getting better but is nowhere near
-working order yet.
+The compiler suite is slowly getting better but it continues to be
+highly experimental. Use in production environments is discouraged.
-=head2 The Long Double Support is Still Experimental
+=head2 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
operations are more likely to be executed by less optimised
libraries).
+=head2 Seen In Perl 5.7 But Gone Now
+
+Some modules were seen in the Perl 5.7 development releases
+but are not present in 5.8.0.
+
+=over 4
+
+=item *
+
+C<Attribute::Handlers> was removed because the implementation of C<my>
+variable attributes changed so much that the Attribute::Handlers will
+require a major rewrite. (This means that you can't use
+Attribute::Handler 0.76 with Perl 5.8.0.)
+
+=item *
+
+C<Time::Piece> (previously known as C<Time::Object>) was removed
+because it was felt that it didn't have enough value in it to be a
+core module. It is still a useful module, though, and is available
+from the CPAN.
+
+=back
+
=head1 Reporting Bugs
If you find what you think is a bug, you might check the articles
projects / p5sagit/p5-mst-13.2.git / blobdiff