=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.
+
+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
+
+=item *
+
+Better Unicode support
+
+=item *
+
+New Thread Implementation
+
+=item *
+
+Many New Modules
+
+=item *
+
+Better Numeric Accuracy
+
+=item *
+
+Safe Signals
+
+=item *
+
+More Extensive Regression Testing
+
+=back
=head1 Incompatible Changes
=head2 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,
+If your pointers are 64 bits wide, the Perl malloc is no longer being
+used because it does not work well with 8-byte pointers. Also,
usually the system mallocs on such platforms are much better optimized
-for such large memory models than the Perl malloc. Such platforms
-include 64-bit Alpha, MIPS, HPPA, PPC, and Sparc.
+for such large memory models than the Perl malloc. Some memory-hungry
+Perl applications like the PDL don't work well with Perl's malloc.
+Finally, other applications than Perl (like modperl) tend to prefer
+the system malloc. Such platforms include Alpha and 64-bit HPPA,
+MIPS, PPC, and Sparc.
=head2 AIX Dynaloading
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
Markov chain input and the few found crashes and lockups have been
fixed.
-=head2 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 C<fields> pragma interface will remain
-available.
-
-The syntaxes C<@a->[...]> and C<@h->{...}> have now been deprecated.
+=head2 REF(...) Instead Of SCALAR(...)
-After years of trying the suidperl is considered to be too complex to
-ever be considered truly secure. The suidperl functionality is likely
-to be removed in a future release.
+A reference to a reference now stringifies as "REF(0x81485ec)" instead
+of "SCALAR(0x81485ec)" in order to be more consistent with the return
+value of ref().
-The C<package;> syntax (C<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, C<use strict;> instead.
+=head2 Deprecations
=over 4
=item *
-A reference to a reference now stringify as "REF(0x81485ec)" instead
-of "SCALAR(0x81485ec)" in order to be more consistent with the return
-value of ref().
+The obsolete chat2 library that should never have been allowed
+to escape the laboratory has been decommissioned.
=item *
=item *
-The obsolete chat2 library that should never have been allowed
-to escape the laboratory has been decommissioned.
+The (bogus) escape sequences \8 and \9 now give an optional warning
+("Unrecognized escape passed through"). There is no need to \-escape
+any C<\w> character.
=item *
-The unimplemented POSIX regex features [[.cc.]] and [[=c=]] are still
-recognised but now cause fatal errors. The previous behaviour of
-ignoring them by default and warning if requested was unacceptable
-since it, in a way, falsely promised that the features could be used.
+The list of filenames from glob() (or <...>) is now by default sorted
+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 *
-The (bogus) escape sequences \8 and \9 now give an optional warning
-("Unrecognized escape passed through"). There is no need to \-escape
-any C<\w> character.
+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.
+More details are in L</"Performance Enhancements">.
=item *
=item *
-The long deprecated uppercase aliases for the string comparison
-operators (EQ, NE, LT, LE, GE, GT) have now been removed.
+The C<package;> syntax (C<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, C<use strict;> instead.
=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.
+The unimplemented POSIX regex features [[.cc.]] and [[=c=]] are still
+recognised but now cause fatal errors. The previous behaviour of
+ignoring them by default and warning if requested was unacceptable
+since it, in a way, falsely promised that the features could be used.
=item *
-The tr///C and tr///U features have been removed and will not return;
-the interface was a mistake. Sorry about that. For similar
-functionality, see pack('U0', ...) and pack('C0', ...).
+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 C<fields> pragma interface will remain
+available.
=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.
-More details are in L</"Performance Enhancements">.
+The syntaxes C<< @a->[...] >> and C<< %h->{...} >> have now been deprecated.
=item *
-The list of filenames from glob() (or <...>) is now by default sorted
-alphabetically to be csh-compliant. (bsd_glob() does still sort platform
-natively, ASCII or EBCDIC, unless GLOB_ALPHASORT is specified.)
+After years of trying the suidperl is considered to be too complex to
+ever be considered truly secure. The suidperl functionality is likely
+to be removed in a future release.
-=back
+=item *
-=head1 Core Enhancements
+The long deprecated uppercase aliases for the string comparison
+operators (EQ, NE, LT, LE, GE, GT) have now been removed.
-=head2 AUTOLOAD Is Now Lvaluable
+=item *
-AUTOLOAD is now lvaluable, meaning that you can add the :lvalue attribute
-to AUTOLOAD subroutines and you can assign to the AUTOLOAD return value.
+The tr///C and tr///U features have been removed and will not return;
+the interface was a mistake. Sorry about that. For similar
+functionality, see pack('U0', ...) and pack('C0', ...).
+
+=back
+
+=head1 Core Enhancements
=head2 PerlIO is Now The Default
creates a pipe, and runs the equivalent of exec('cat', '/etc/motd') in
the child process.
-=item *
-
-The following builtin functions are now overridable: chop(), chomp(),
-each(), keys(), pop(), push(), shift(), splice(), unshift().
-
-=item *
-
-Formats now support zero-padded decimal fields.
+=back
-=item *
+=head2 Safe Signals
-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
-arithmetics. (Previously Perl always preferred floating point numbers
-in its math.)
+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 (between opcodes).
-=item *
+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.
-The printf() and sprintf() now support parameter reordering using the
-C<%\d+\$> and C<*\d+\$> syntaxes. For example
+=head2 Unicode Overhaul
- print "%2\$s %1\$s\n", "foo", "bar";
+Unicode in general should be now much more usable than in Perl 5.6.0
+(or even in 5.6.1). Unicode can be used in hash keys, Unicode in
+regular expressions should work now, Unicode in tr/// should work now,
+Unicode in I/O should work now.
-will print "bar foo\n"; This feature helps in writing
-internationalised software.
+=over 4
=item *
-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)
+The Unicode Character Database coming with Perl has been upgraded
+to Unicode 3.1.1. For more information, see http://www.unicode.org/.
=item *
-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
+the lib/unicore subdirectory. The most notable omission, for space
considerations, is the Unihan database.
=item *
=back
-=head2 Signals Are Now Safe
-
-Perl used to be fragile in that signals arriving at inopportune moments
-could corrupt Perl's internal state.
-
=head2 Understanding of Numbers
In general a lot of fixing has happened in the area of Perl's
and C<atof()> seem to have bugs, Perl tries to work around their
deficiencies. This results hopefully in more accurate numbers.
+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 to often slightly faster and always less lossy
+arithmetics. (Previously Perl always preferred floating point numbers
+in its math.)
+
+=head2 Miscellaneous Enhancements
+
=over 4
=item *
+AUTOLOAD is now lvaluable, meaning that you can add the :lvalue attribute
+to AUTOLOAD subroutines and you can assign to the AUTOLOAD return value.
+
+=item *
+
C<perl -d:Module=arg,arg,arg> now works (previously one couldn't pass
in multiple arguments.)
=item *
-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.
-
-=item *
-
-Lexicals II: lexicals leaked at file scope into subroutines that
-were declared before the lexicals.
+Formats now support zero-padded decimal fields.
=item *
Lvalue subroutines can now return C<undef> in list context.
+However, the lvalue subroutine feature still remains experimental.
=item *
=item *
+The following builtin functions are now overridable: each(), keys(),
+pop(), push(), shift(), splice(), unshift().
+
+=item *
+
C<pack('U0a*', ...)> can now be used to force a string to UTF8.
=item *
=item *
-prototype(\&) is now available.
+The printf() and sprintf() now support parameter reordering using the
+C<%\d+\$> and C<*\d+\$> syntaxes. For example
+
+ print "%2\$s %1\$s\n", "foo", "bar";
+
+will print "bar foo\n". This feature helps in writing
+internationalised software, and in general when the order
+of the parameters can vary.
=item *
-Right-hand side magic (GMAGIC) could in many cases such as string
-concatenation be invoked too many times.
+prototype(\&) is now available.
=item *
-The rules for allowing underscores (underbars) in numeric constants
-have been relaxed and simplified: now you can have an underscore
-simply B<between digits>.
+prototype(\[$@%&]) is now available to implicitly create references
+(useful for example if you want to emulate the tie() interface).
=item *
-An UNTIE method is now available.
+untie() will now call an UNTIE() hook if it exists. See L<perltie>
+for details.
=item *
=item *
-C<eval "v200"> now works.
+The rules for allowing underscores (underbars) in numeric constants
+have been relaxed and simplified: now you can have an underscore
+simply B<between digits>.
=back
=item *
-C<Devel::PPPort>, from Kenneth Albanowski, has been added. It is
-primarily used by C<h2xs> to enhance portability of of XS modules
-between different versions of Perl.
+C<Devel::PPPort>, originally from Kenneth Albanowski and now
+maintained by Paul Marquess, has been added. It is primarily used
+by C<h2xs> to enhance portability of of XS modules between different
+versions of Perl.
=item *
print $digest, "\n"; # 01d19d9d2045e005c3f1b80e8b164de1
NOTE: the C<MD5> backward compatibility module is deliberately not
-included since its use is discouraged.
+included since its further use is discouraged.
=item *
=item *
C<I18N::LangTags> has functions for dealing with RFC3066-style
-language tags, by Sean Burke. See <I18N::LangTags>.
+language tags, by Sean Burke. See L<I18N::LangTags>.
=item *
=item *
C<List::Util> is a selection of general-utility list subroutines, like
-sum(), min(), first(), and shuffle(), by Graham barr. See L<List::Util>.
+sum(), min(), first(), and shuffle(), by Graham Barr. See L<List::Util>.
=item *
necessary to use it with PerlIO::Via as in :
use MIME::QuotedPrint;
- open($fh,">Via(MIME::QuotedPrint)",$path)
+ open($fh,">Via(MIME::QuotedPrint)",$path);
See L<MIME::QuotedPrint>.
code), from Nick Ing-Simmons.
use MIME::QuotedPrint;
- open($fh,">Via(MIME::QuotedPrint)",$path)
+ open($fh,">Via(MIME::QuotedPrint)",$path);
This will automatically convert everything output to C<$fh>
to Quoted-Printable. See L<PerlIO::Via>.
=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 *
-C<Test::Simple> has the- basic utilities for writing tests, by Michael
+C<Test::Simple> has basic utilities for writing tests, by Michael
Schwern. See L<Test::Simple>.
=item *
=item *
-C<threads> is an interface interpreter threads, by Arthur Bergman.
+C<threads> is an interface to interpreter threads, by Arthur Bergman.
Interpreter threads (ithreads) is the new thread model introduced in
-Perl 5.6 but then available only as an internal interface for
-extension writers. See L<threads>.
+Perl 5.6 but only available as an internal interface for extension
+writers (and for Win32 Perl for C<fork()> emulation). See L<threads>.
=item *
=item *
-AutoLoader can now be disabled with C<no AutoLoader;>,
+AutoLoader can now be disabled with C<no AutoLoader;>.
=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 *
-C<%INC> now localised in a Safe compartment so that use/require work.
+In Safe the C<%INC> now localised in a Safe compartment so that
+use/require work.
+
+=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.
=item *
=item *
-The C<vars> pragma now supports declaring fully qualified variables.
+The vars pragma now supports declaring fully qualified variables.
(Something that C<our()> does not and will not support.)
=item *
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 *
-C<perlivp> is a new utility for doing Installation Verification
-Procedure after installing Perl.
+C<perlivp> is a new Installation Verification Procedure utility
+for running any time after installing Perl.
=item *
=item *
perlebcdic contains considerations for running Perl on EBCDIC platforms.
-Note that unfortunately EBCDIC platforms that used to supported back in
-Perl 5.005 are still unsupported by Perl 5.7.0; the plan, however, is to
-bring them back to the fold.
=item *
=item *
+perlpacktut is a pack() tutorial.
+
+=item *
+
perlpod has been rewritten to be clearer and to record the best
practices gathered over the years.
=item *
-perlpodstyle is a more formal specification of the pod format,
+perlpodspec is a more formal specification of the pod format,
mainly of interest for writers of pod applications, not to
people writing in pod.
=item *
-perlposix-bc explains using Perl on the POSIX-BC platform
-(an EBCDIC mainframe platform).
-
-=item *
-
perlretut is a regular expression tutorial.
=item *
=item *
-map() that changes the size of the list should now work faster.
-
-=item *
-
-sort() has been changed to use mergesort internally as opposed to the
-earlier quicksort. For very small lists this may result in slightly
-slower sorting times, but in general the speedup should be at least
-20%. Additional bonuses are that the worst case behaviour of sort()
-is now better (in computer science terms it now runs in time O(N log N),
-as opposed to quicksort's Theta(N**2) worst-case run time behaviour),
-and that sort() is now stable (meaning that elements with identical
-keys will stay ordered as they were before the sort).
+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 *
+
+sort() has been changed to use primarily mergesort internally as
+opposed to the earlier quicksort. For very small lists this may
+result in slightly slower sorting times, but in general the speedup
+should be at least 20%. Additional bonuses are that the worst case
+behaviour of sort() is now better (in computer science terms it now
+runs in time O(N log N), as opposed to quicksort's Theta(N**2)
+worst-case run time behaviour), and that sort() is now stable
+(meaning that elements with identical keys will stay ordered as they
+were before the sort). See the C<sort> pragma for information.
+
+The story in more detail: suppose you want to serve yourself a little
+slice of Pi.
+
+ @digits = ( 3,1,4,1,5,9 );
+
+A numerical sort of the digits will yield (1,1,3,4,5,9), as expected.
+Which C<1> comes first is hard to know, since one C<1> looks pretty
+much like any other. You can regard this as totally trivial,
+or somewhat profound. However, if you just want to sort the even
+digits ahead of the odd ones, then what will
+
+ sort { ($a % 2) <=> ($b % 2) } @digits;
+
+yield? The only even digit, C<4>, will come first. But how about
+the odd numbers, which all compare equal? With the quicksort algorithm
+used to implement Perl 5.6 and earlier, the order of ties is left up
+to the sort. So, as you add more and more digits of Pi, the order
+in which the sorted even and odd digits appear will change.
+and, for sufficiently large slices of Pi, the quicksort algorithm
+in Perl 5.8 won't return the same results even if reinvoked with the
+same input. The justification for this rests with quicksort's
+worst case behavior. If you run
+
+ sort { $a <=> $b } ( 1 .. $N , 1 .. $N );
+
+(something you might approximate if you wanted to merge two sorted
+arrays using sort), doubling $N doesn't just double the quicksort time,
+it I<quadruples> it. Quicksort has a worst case run time that can
+grow like N**2, so-called I<quadratic> behaviour, and it can happen
+on patterns that may well arise in normal use. You won't notice this
+for small arrays, but you I<will> notice it with larger arrays,
+and you may not live long enough for the sort to complete on arrays
+of a million elements. So the 5.8 quicksort scrambles large arrays
+before sorting them, as a statistical defence against quadratic behaviour.
+But that means if you sort the same large array twice, ties may be
+broken in different ways.
+
+Because of the unpredictability of tie-breaking order, and the quadratic
+worst-case behaviour, quicksort was I<almost> replaced completely with
+a stable mergesort. I<Stable> means that ties are broken to preserve
+the original order of appearance in the input array. So
+
+ sort { ($a % 2) <=> ($b % 2) } (3,1,4,1,5,9);
+
+will yield (4,3,1,1,5,9), guaranteed. The even and odd numbers
+appear in the output in the same order they appeared in the input.
+Mergesort has worst case O(NlogN) behaviour, the best value
+attainable. And, ironically, this mergesort does particularly
+well where quicksort goes quadratic: mergesort sorts (1..$N, 1..$N)
+in O(N) time. But quicksort was rescued at the last moment because
+it is faster than mergesort on certain inputs and platforms.
+For example, if you really I<don't> care about the order of even
+and odd digits, quicksort will run in O(N) time; it's very good
+at sorting many repetitions of a small number of distinct elements.
+The quicksort divide and conquer strategy works well on platforms
+with relatively small, very fast, caches. Eventually, the problem gets
+whittled down to one that fits in the cache, from which point it
+benefits from the increased memory speed.
+
+Quicksort was rescued by implementing a sort pragma to control aspects
+of the sort. The B<stable> subpragma forces stable behaviour,
+regardless of algorithm. The B<_quicksort> and B<_mergesort>
+subpragmas are heavy-handed ways to select the underlying implementation.
+The leading C<_> is a reminder that these subpragmas may not survive
+beyond 5.8. More appropriate mechanisms for selecting the implementation
+exist, but they wouldn't have arrived in time to save quicksort.
=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 *
+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
+ sh /path/to/perl/source/Configure -Dmksymlinks ...
+
+This will create in /tmp/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.
+
+=item *
+
For Perl developers several new make targets for profiling
and debugging have been added, see L<perlhack>.
=item *
+NEC SUPER-UX is now supported.
+
+=item *
+
Amdahl UTS UNIX mainframe platform is now supported.
=item *
=head1 Selected Bug Fixes
-Numerous memory leaks and uninitialized memory accesses have been hunted down.
-Most importantly anonymous subs used to leak quite a bit.
+Numerous memory leaks and uninitialized memory accesses have been
+hunted down. Most importantly anonymous subs used to leak quite
+a bit.
=over 4
=item *
+The autouse pragma didn't work for Multi::Part::Function::Names.
+
+=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.
+
+=item *
+
+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.
+
+=item *
+
+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.
+
+=item *
+
+The order of DESTROYs has been made more predictable.
+
+=item *
+
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 *
-C<*foo{FORMAT}> now works.
+Perl 5.6.0 could emit spurious warnings about redefinition of dl_error()
+when statically building extensions into perl. This has been corrected.
=item *
-Lexical warnings now propagating correctly between scopes.
+L<dprofpp> -R didn't work.
=item *
-Line renumbering with eval and C<#line> now works.
-
+C<*foo{FORMAT}> now works.
=item *
-Fixed numerous memory leaks, especially in eval "".
+Infinity is now recognized as a number.
=item *
-Modulus of unsigned numbers now works (4063328477 % 65535 used to
-return 27406, instead of 27047).
+UNIVERSAL::isa no longer caches methods incorrectly. (This broke
+the Tk extension with 5.6.0.)
=item *
-Some "not a number" warnings introduced in 5.6.0 eliminated to be
-more compatible with 5.005. Infinity is now recognised as a number.
+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.
=item *
-our() variables will not cause "will not stay shared" warnings.
+Lexicals II: lexicals leaked at file scope into subroutines that
+were declared before the lexicals.
=item *
-pack "Z" now correctly terminates the string with "\0".
+Lexical warnings now propagating correctly between scopes
+and into C<eval "...">.
=item *
-Fix password routines which in some shadow password platforms
-(e.g. HP-UX) caused getpwent() to return every other entry.
+C<use warnings qw(FATAL all)> did not work as intended. This has been
+corrected.
=item *
-printf() no longer resets the numeric locale to "C".
+warnings::enabled() now reports the state of $^W correctly if the caller
+isn't using lexical warnings.
=item *
-C<q(a\\b)> now parses correctly as C<'a\\b'>.
+Line renumbering with eval and C<#line> now works.
=item *
-Printing quads (64-bit integers) with printf/sprintf now works
-without the q L ll prefixes (assuming you are on a quad-capable platform).
+Fixed numerous memory leaks, especially in eval "".
=item *
-Regular expressions on references and overloaded scalars now work.
+mkdir() now ignores trailing slashes in the directory name,
+as mandated by POSIX.
=item *
-scalar() now forces scalar context even when used in void context.
+Some versions of glibc have a broken modfl(). This affects builds
+with C<-Duselongdouble>. This version of Perl detects this brokenness
+and has a workaround for it. The glibc release 2.2.2 is known to have
+fixed the modfl() bug.
=item *
-sort() arguments are now compiled in the right wantarray context
-(they were accidentally using the context of the sort() itself).
+Modulus of unsigned numbers now works (4063328477 % 65535 used to
+return 27406, instead of 27047).
=item *
-Changed the POSIX character class C<[[:space:]]> to include the (very
-rare) vertical tab character. Added a new POSIX-ish character class
-C<[[:blank:]]> which stands for horizontal whitespace (currently,
-the space and the tab).
+Some "not a number" warnings introduced in 5.6.0 eliminated to be
+more compatible with 5.005. Infinity is now recognised as a number.
=item *
-$AUTOLOAD, sort(), lock(), and spawning subprocesses
-in multiple threads simultaneously are now thread-safe.
+Numeric conversions did not recognize changes in the string value
+properly in certain circumstances.
=item *
-Allow read-only string on left hand side of non-modifying tr///.
+Attributes (like :shared) didn't work with our().
=item *
-Several Unicode fixes (but still not perfect).
+our() variables will not cause "will not stay shared" warnings.
-=over 8
+=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 *
-BOMs (byte order marks) in the beginning of Perl files
-(scripts, modules) should now be transparently skipped.
-UTF-16 (UCS-2) encoded Perl files should now be read correctly.
+pack "Z" now correctly terminates the string with "\0".
=item *
-The character tables have been updated to Unicode 3.0.1.
+Fix password routines which in some shadow password platforms
+(e.g. HP-UX) caused getpwent() to return every other entry.
=item *
-chr() for values greater than 127 now create utf8 when under use
-utf8.
+The PERL5OPT environment variable (for passing command line arguments
+to Perl) didn't work for more than a single group of options.
=item *
-Comparing with utf8 data does not magically upgrade non-utf8 data into
-utf8.
+PERL5OPT with embedded spaces didn't work.
=item *
-C<IsAlnum>, C<IsAlpha>, and C<IsWord> now match titlecase.
+printf() no longer resets the numeric locale to "C".
=item *
-Concatenation with the C<.> operator or via variable interpolation,
-C<eq>, C<substr>, C<reverse>, C<quotemeta>, the C<x> operator,
-substitution with C<s///>, single-quoted UTF8, should now work--in
-theory.
+C<qw(a\\b)> now parses correctly as C<'a\\b'>.
=item *
-The C<tr///> operator now works I<slightly> better but is still rather
-broken. Note that the C<tr///CU> functionality has been removed (but
-see pack('U0', ...)).
+pos() did not return the correct value within s///ge in earlier
+versions. This is now handled correctly.
=item *
-vec() now refuses to deal with characters >255.
+Printing quads (64-bit integers) with printf/sprintf now works
+without the q L ll prefixes (assuming you are on a quad-capable platform).
=item *
-Zero entries were missing from the Unicode classes like C<IsDigit>.
+Regular expressions on references and overloaded scalars now work.
=item *
-chop(@list) in list context returned the characters chopped in
-reverse order. This has been reversed to be in the right order.
+Right-hand side magic (GMAGIC) could in many cases such as string
+concatenation be invoked too many times.
=item *
-The order of DESTROYs has been made more predictable.
+scalar() now forces scalar context even when used in void context.
=item *
-mkdir() now ignores trailing slashes in the directory name,
-as mandated by POSIX.
+SOCKS support is now much more robust.
=item *
-Attributes (like :shared) didn't work with our().
+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 *
-The PERL5OPT environment variable (for passing command line arguments
-to Perl) didn't work for more than a single group of options.
+Changed the POSIX character class C<[[:space:]]> to include the (very
+rarely used) vertical tab character. Added a new POSIX-ish character
+class C<[[:blank:]]> which stands for horizontal whitespace
+(currently, the space and the tab).
=item *
=item *
-All but the first argument of the IO syswrite() method are now optional.
+Some cases of inconsistent taint propagation (such as within hash
+values) have been fixed.
=item *
-Tie::ARRAY SPLICE method was broken.
+The RE engine found in Perl 5.6.0 accidentally pessimised certain kinds
+of simple pattern matches. These are now handled better.
=item *
-vec() now tries to work with characters <= 255 when possible, 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.
+Regular expression debug output (whether through C<use re 'debug'>
+or via C<-Dr>) now looks better.
=item *
-The autouse pragma didn't work for Multi::Part::Function::Names.
+Multi-line matches like C<"a\nxb\n" =~ /(?!\A)x/m> were flawed. The
+bug has been fixed.
=item *
-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.
+Use of $& could trigger a core dump under some situations. This
+is now avoided.
=item *
-L<dprofpp> -R didn't work.
+The regular expression captured submatches ($1, $2, ...) are now
+more consistently unset if the match fails, instead of leaving false
+data lying around in them.
=item *
-PERL5OPT with embedded spaces didn't work.
+readline() on files opened in "slurp" mode could return an extra "" at
+the end in certain situations. This has been corrected.
=item *
-L<Sys::Syslog> ignored the C<LOG_AUTH> constant.
+Autovivification of symbolic references of special variables described
+in L<perlvar> (as in C<${$num}>) was accidentally disabled. This works
+again now.
=item *
-Some versions of glibc have a broken modfl(). This affects builds
-with C<-Duselongdouble>. This version of Perl detects this brokenness
-and has a workaround for it. The glibc release 2.2.2 is known to have
-fixed the modfl() bug.
+Sys::Syslog ignored the C<LOG_AUTH> constant.
=item *
-Linux previously had problems related to sockaddrlen when using
-accept(), revcfrom() (in Perl: recv()), getpeername(), and getsockname().
+All but the first argument of the IO syswrite() method are now optional.
=item *
-Previously DYNIX/ptx had problems in its Configure probe for non-blocking I/O.
+$AUTOLOAD, sort(), lock(), and spawning subprocesses
+in multiple threads simultaneously are now thread-safe.
=item *
-Windows
-
-=over 8
+Tie::ARRAY SPLICE method was broken.
=item *
-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++).
+Allow read-only string on left hand side of non-modifying tr///.
=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.
+Several Unicode fixes.
+
+=over 8
=item *
-Duping socket handles with open(F, ">&MYSOCK") now works under Windows 9x.
+BOMs (byte order marks) in the beginning of Perl files
+(scripts, modules) should now be transparently skipped.
+UTF-16 (UCS-2) encoded Perl files should now be read correctly.
=item *
-HTML files will be installed in c:\perl\html instead of c:\perl\lib\pod\html
+The character tables have been updated to Unicode 3.1.1.
=item *
-The makefiles now provide a single switch to bulk-enable all the features
-enabled in ActiveState ActivePerl (a popular Win32 binary distribution).
+Comparing with utf8 data does not magically upgrade non-utf8 data
+into utf8.
-=back
+=item *
-=back
+C<IsAlnum>, C<IsAlpha>, and C<IsWord> now match titlecase.
=item *
-UNIVERSAL::isa no longer caches methods incorrectly. (This broke
-the Tk extension with 5.6.0.)
+Concatenation with the C<.> operator or via variable interpolation,
+C<eq>, C<substr>, C<reverse>, C<quotemeta>, the C<x> operator,
+substitution with C<s///>, single-quoted UTF8, should now work.
=item *
-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.
+The C<tr///> operator now works. Note that the C<tr///CU>
+functionality has been removed (but see pack('U0', ...)).
=item *
-SOCKS support is now much more robust.
+C<eval "v200"> now works.
=item *
-If your file system supports symbolic links you can build Perl outside
-of the source directory by
+Perl 5.6.0 parsed m/\x{ab}/ incorrectly, leading to spurious warnings.
+This has been corrected.
- mkdir /tmp/perl/build/directory
- cd /tmp/perl/build/directory
- sh /path/to/perl/source/Configure -Dmksymlinks ...
+=item *
-This will create in /tmp/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
+Zero entries were missing from the Unicode classes like C<IsDigit>.
- make all test
+=back
-and Perl will be built and tested, all in /tmp/perl/build/directory.
+=item *
+
+Large unsigned numbers (those above 2**31) could sometimes lose their
+unsignedness, causing bogus results in arithmetic operations.
=back
All BSDs
-Setting C<$0> now works (as much as possible; see perlvar for details).
+Setting C<$0> now works (as much as possible; see L<perlvar> for details).
=item *
=item *
+Previously DYNIX/ptx had problems in its Configure probe for non-blocking I/O.
+
+=item *
+
EPOC
EPOC update after Perl 5.6.0. See README.epoc.
Linux
+=over 8
+
+=item *
+
Long doubles should now work (see INSTALL).
=item *
+Linux previously had problems related to sockaddrlen when using
+accept(), revcfrom() (in Perl: recv()), getpeername(), and getsockname().
+
+=back
+
+=item *
+
MacOS Classic
Compilation of the standard Perl distribution in MacOS Classic should
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 *
+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++).
+
+=item *
+
Better chdir() return value for a non-existent directory.
=item *
+Duping socket handles with open(F, ">&MYSOCK") now works under Windows 9x.
+
+=item *
+
New %ENV entries now propagate to subprocesses.
=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 *
+fork() emulation has been improved in various ways, but still continues
+to be experimental. See L<perlfork> for known bugs and caveats.
+
+=item *
+
A failed (pseudo)fork now returns undef and sets errno to EAGAIN.
=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 *
+
+The makefiles now provide a single switch to bulk-enable all the features
+enabled in ActiveState ActivePerl (a popular Win32 binary distribution).
+
+=item *
+
Allow REG_EXPAND_SZ keys in the registry.
=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 *
-C<File::Spec->tmpdir()> now prefers C:/temp over /tmp
+C<File::Spec->tmpdir()> now prefers C:/temp over /tmp
(works better when perl is running as service).
=item *
=item *
-wait() and waitpid() now work much better.
+wait(), waitpid() and backticks now return the correct exit status under
+Windows 9x.
=item *
The various "opened only for", "on closed", "never opened" warnings
drop the C<main::> prefix for filehandles in the C<main> package,
-for example C<STDIN> instead of <main::STDIN>.
+for example C<STDIN> instead of C<main::STDIN>.
=item *
=item *
-Using arrays or hashes as references (e.g. C<%foo->{bar}> has been
-deprecated for a while. Now you will get an optional warning.
+Using arrays or hashes as references (e.g. C<< %foo->{bar} >>
+has been deprecated for a while. Now you will get an optional warning.
=back
=item *
-Added rsignal(), whichsig(), do_join() to the publicised API.
+Added rsignal(), whichsig(), do_join(), op_clear, op_null,
+ptr_table_clear(), ptr_table_free(), sv_setref_uv(), and several UTF-8
+interfaces to the publicised API. For the full list of the available
+APIs see L<perlapi>.
=item *
=item *
-Added is_utf8_char(), is_utf8_string(), bytes_to_utf8(), and utf8_to_bytes().
-
-=item *
-
-Now xsubs can have attributes just like subs.
-
-=item *
-
-Some new APIs: ptr_table_clear(), ptr_table_free(), sv_setref_uv().
-For the full list of the available APIs see L<perlapi>.
+Now xsubs can have attributes just like subs. (Well, at least the
+built-in attributes.)
=item *
=item *
-There are now several profiling make targets
-
-=item *
-
-The C<op_clear> and C<op_null> are now exported.
+There are now several profiling make targets.
=back
=head1 New Tests
-Several new tests have been added, especially for the F<lib> subsection.
+Several new tests have been added, especially for the F<lib>
+subsection. There are now about 34 000 individual tests (spread over
+about 530 test scripts), in the regression suite (5.6.1 has about
+11700 tests, in 258 test scripts) Many of the new tests are introduced
+by the new modules, but still in general Perl is now more thoroughly
+tested.
+
+Because of the large number of tests, running the regression suite
+will take considerably longer time than it used to: expect the suite
+to take up to 4-5 times longer to run than in perl 5.6. In a really
+fast machine you can hope to finish the suite in about 5 minutes
+(wallclock time).
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
=head1 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.
-
=head2 AIX
=over 4
=head2 Amiga Perl Invoking Mystery
One cannot call Perl using the C<volume:> syntax, that is, C<perl -v>
-works, but for example C<bin:perl -v> doesn't. The exact reason is
+works, but for example C<bin:perl -v> doesn't. The exact reason isn't
known but the current suspect is the F<ixemul> library.
=head2 lib/ftmp-security tests warn 'system possibly insecure'
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 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.
-
+There is one known test failure with a default configuration:
+
+ [.run]switches..........................FAILED on test 1
+
=head2 Win32
In multi-CPU boxes there are some problems with the I/O buffering:
Code like the above is known to leak memory every time the local()
is executed.
+=head2 Localising Tied Arrays and Hashes Is Broken
+
+ local %tied_array;
+
+doesn't work as one would expect: the old value is restored
+incorrectly.
+
=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 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>).
-
=head2 Building Extensions Can Fail Because Of Largefiles
Some extensions like mod_perl are known to have issues with
all binaries with different ideas about file offsets, all this is
platform-dependent.
+=head2 Unicode Support on EBCDIC Still Spotty
+
+Though mostly working, Unicode support still has problem spots on
+EBCDIC platforms. One such known spot are the C<\p{}> and C<\P{}>
+regular expression constructs for code points less than 256: the
+pP are testing for Unicode code points, not knowing about EBCDIC.
+
=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