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
+
+(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 distributors 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
+suidperl 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/ ).
=head1 Incompatible Changes
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<perldelta/Performance Enhancements>.
+More details are in L</"Performance Enhancements">.
+
+=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.)
=back
=head1 Core Enhancements
+=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".
+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', $path) || ...
+
+or on already opened handles via extended C<binmode>:
+
+ binmode($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
+platform supports it (mostly Unixes).
+
+Layers to be applied by default may be specified via the 'open' pragma.
+
+See L</"Installation and Configuration Improvements"> for the effects
+of PerlIO on your architecture name.
+
+=item *
+
+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($fh,">:utf8","Uni.txt");
+
+Note for EBCDIC users: the pseudo layer ":utf8" is erroneously named
+for you since it's not UTF-8 what you will be getting but instead
+UTF-EBCDIC. See L<perlunicode>, L<utf8>, and
+http://www.unicode.org/unicode/reports/tr16/ for more information.
+In future releases this naming may change.
+
+=item *
+
+File handles can translate character encodings from/to Perl's internal
+Unicode form on read/write via the ":encoding()" layer.
+
+=item *
+
+File handles can be opened to "in memory" files held in Perl scalars via:
+
+ open($fh,'>', \$variable) || ...
+
+=item *
+
+Anonymous temporary files are available without need to
+'use FileHandle' or other module via
+
+ open($fh,"+>", undef) || ...
+
+That is a literal undef, not an undefined value.
+
+=item *
+
+The list form of C<open> is now implemented for pipes (at least on Unix):
+
+ open($fh,"-|", 'cat', '/etc/motd')
+
+creates a pipe, and runs the equivalent of exec('cat', '/etc/motd') in
+the child process.
+
+=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.
=item *
-
-The printf and sprintf now support parameter reordering using the
-C<%\d+\$> and C<*\d+\$> syntaxes.
+
+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.)
+
+=item *
+
+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.
+
+=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)
+
+=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
+considerations, is the Unihan database.
+
+=item *
+
+The Unicode character classes \p{Blank} and \p{SpacePerl} have been
+added. "Blank" is like C isblank(), that is, it contains only
+"horizontal whitespace" (the space character is, the newline isn't),
+and the "SpacePerl" is the Unicode equivalent of C<\s> (\p{Space}
+isn't, since that includes the vertical tabulator character, whereas
+C<\s> doesn't.)
=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
+
+=over 4
+
+=item *
+
+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.
+
+See L<B::Concise> for more information.
+
+=item *
+
+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 *
+
+Cwd has now a split personality: if possible, an extension is used,
+(this will hopefully be both faster and more secure and robust) but
+if not possible, the familiar Perl library implementation is used.
+
+=item *
+
+Digest, a frontend module for calculating digests (checksums),
+from Gisle Aas, has been added.
+
+See L<Digest> for more information.
+
+=item *
+
+Digest::MD5 for calculating MD5 digests (checksums), by Gisle Aas,
+has been added.
+
+ use Digest::MD5 'md5_hex';
+
+ $digest = md5_hex("Thirsty Camel");
+
+ print $digest, "\n"; # 01d19d9d2045e005c3f1b80e8b164de1
+
+NOTE: the MD5 backward compatibility module is deliberately not
+included since its use is discouraged.
+
+See L<Digest::MD5> for more information.
+
+=item *
+
+Encode, by Nick Ing-Simmons, provides a mechanism to translate
+between different character encodings. Support for Unicode,
+ISO-8859-*, ASCII, CP*, KOI8-R, and three variants of EBCDIC are
+compiled in to the module. Several other encodings (like Japanese,
+Chinese, and MacIntosh encodings) are included and will be loaded at
+runtime.
+
+Any encoding supported by Encode module is also available to the
+":encoding()" layer if PerlIO is used.
+
+See L<Encode> for more information.
+
+=item *
+
+Filter::Simple is an easy-to-use frontend to Filter::Util::Call,
+from Damian Conway.
+
+ # in MyFilter.pm:
+
+ package MyFilter;
+
+ use Filter::Simple sub {
+ while (my ($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 L<Filter::Simple> for more information.
+
+=item *
+
+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 *
+
+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 L<Locale::Constants>, L<Locale::Country>, L<Locale::Currency>,
+and L<Locale::Language> for more information.
+
+=item *
+
+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 L<MIME::Base64> for more information.
+
+=item *
+
+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)",$path)
+
+See L<MIME::QuotedPrint> for more information.
+
+=item *
+
+PerlIO::scalar, by Nick Ing-Simmons, provides the implementation of
+IO to "in memory" Perl scalars as discussed above. It also serves as
+an example of a loadable layer. Other future possibilities include
+PerlIO::array and PerlIO::code. See L<PerlIO::scalar> for more
+information.
+
+=item *
+
+PerlIO::Via, by Nick Ing-Simmons, acts as a PerlIO layer and wraps
+PerlIO layer functionality provided by a class (typically implemented
+in perl code).
+
+ use MIME::QuotedPrint;
+ open($fh,">Via(MIME::QuotedPrint)",$path)
+
+This will automatically convert everything output to C<$fh>
+to Quoted-Printable. See L<PerlIO::via> for more information.
+
+=item *
+
+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.
+
+=item *
+
+Switch from Damian Conway has been added. Just by saying
+
+ use Switch;
+
+you have C<switch> and C<case> available in Perl.
+
+ use Switch;
+
+ switch ($val) {
+
+ case 1 { print "number 1" }
+ case "a" { print "string a" }
+ case [1..10,42] { print "number in list" }
+ case (@array) { print "number in list" }
+ case /\w+/ { print "pattern" }
+ case qr/\w+/ { print "pattern" }
+ case (%hash) { print "entry in hash" }
+ case (\%hash) { print "entry in hash" }
+ case (\&sub) { print "arg to subroutine" }
+ else { print "previous case not true" }
+ }
+
+See L<Switch> for more information.
+
+=item *
+
+Text::Balanced from Damian Conway has been added, for
+extracting delimited text sequences from strings.
+
+ use Text::Balanced 'extract_delimited';
+
+ ($a, $b) = extract_delimited("'never say never', he never said", "'", '');
+
+$a will be "'never say never'", $b will be ', he never said'.
+
+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 algorithms. See L<Text::Balanced> for more information.
+
+=item *
+
+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, by Tim Jenness, is a test extension that exercises XS
+typemaps. Nothing gets installed but for extension writers the code
+is worth studying.
+
+=back
+
+=head2 Updated And Improved Modules and Pragmata
+
+=over 4
+
+=item *
+
+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.
+
+=item *
+
+Class::Struct can now define the classes in compile time.
+
+=item *
+
+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/ )
+
+=item *
+
+Devel::Peek now has an interface for the Perl memory statistics
+(this works only if you are using perl's malloc, and if you have
+compiled with debugging).
+
+=item *
+
+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() function.
+
+=item *
+
+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.
+
+=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.
+
+=item *
+
+The C<open> pragma allows layers other than ":raw" and ":crlf" when
+using PerlIO.
+
+=item *
+
+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.
+
+=item *
+
+The Test module has been significantly enhanced. Its use is
+greatly recommended for module writers.
+
+=item *
+
+The utf8:: name space (as in the pragma) provides various
+Perl-callable functions to provide low level access to Perl's
+internal Unicode representation. At the moment only length()
+has been implemented.
+
+=back
+
+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.
+
=head1 Performance Enhancements
=over 4
=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 *
+
+unshift() should now be noticeably faster.
+
+=back
+
+=head1 Utility Changes
+
+=over 4
+
+=item *
+
+h2xs now produces template README.
+
+=item *
+
+s2p has been completely rewritten in Perl. (It is in fact a full
+implementation of sed in Perl.)
+
+=item *
+
+xsubpp now supports OUT keyword.
=back
+=head1 New Documentation
+
+=head2 perlclib
+
+Internal replacements for standard C library functions.
+(Interesting only for extension writers and Perl core hackers.)
+
+=head2 perliol
+
+Internals of PerlIO with layers.
+
+=head2 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 L<perlaix>.
+
+=head2 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 L<perlbs2000>.
+
+=head2 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 compile MacPerl
+some additional steps are required, and this file documents those
+steps. On install README.macos will be installed as L<perlmacos>.
+
+=head2 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 L<perlmpeix>.
+
+=head2 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 L<perlsolaris>.
+
+=head2 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 L<perlvos>.
+
+=head2 Porting/repository.pod
+
+Documentation on how to use the Perl source repository has been added.
+
=head1 Installation and Configuration Improvements
=over 4
=item *
+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.
+
+=item *
+
+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.)
+
+=item *
+
+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.
+
+=item *
+
+Building Berkeley DB3 for compatibility modes for DB, NDBM, and ODBM
+has been documented in INSTALL.
+
+=item *
+
+If you are on IRIX or Tru64 platforms, new profiling/debugging options
+have been added, see L<perlhack> for more information about pixie and
+Third Degree.
+
+=back
+
+=head2 New Or Improved Platforms
+
+For the list of platforms known to support Perl,
+see L<perlport/"Supported Platforms">.
+
+=over 4
+
+=item *
+
+AIX dynamic loading should be now better supported.
+
+=item *
+
+After a long pause, AmigaOS has been verified to be happy with Perl.
+
+=item *
+
+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 L<perlos390>,
+L<perlbs2000> (for POSIX-BC), and L<perlvmesa> for more information.
+
+=item *
+
+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 *
+
+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)
+
+=item *
+
+NCR MP-RAS is now supported.
+
+=item *
+
+NonStop-UX is now supported.
+
+=item *
+
+Amdahl UTS is now supported.
+
+=item *
+
+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.
+
+=back
+
+=head2 Generic Improvements
+
+=over 4
+
+=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,
+when building the Perl binary. The only exception to this is SunOS 4.x,
which needs them.
+=item *
+
+Some new Configure symbols, useful for extension writers:
+
+=over 8
+
+=item d_cmsghdr
+
+For struct cmsghdr.
+
+=item d_fcntl_can_lock
+
+Whether fcntl() can be used for file locking.
+
+=item d_fsync
+
+=item d_getitimer
+
+=item d_getpagsz
+
+For getpagesize(), though you should prefer POSIX::sysconf(_SC_PAGE_SIZE))
+
+=item d_msghdr_s
+
+For struct msghdr.
+
+=item need_va_copy
+
+Whether one needs to use Perl_va_copy() to copy varargs.
+
+=item d_readv
+
+=item d_recvmsg
+
+=item d_sendmsg
+
+=item sig_size
+
+The number of elements in an array needed to hold all the available signals.
+
+=item d_sockatmark
+
+=item d_strtoq
+
+=item d_u32align
+
+Whether one needs to access character data aligned by U32 sized pointers.
+
+=item d_ualarm
+
+=item d_usleep
+
+=back
+
+=item *
+
+Removed Configure symbols: the PDP-11 memory model settings: huge,
+large, medium, models.
+
+=item *
+
+SOCKS support is now much more robust.
+
+=item *
+
+If your file system 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 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 perl/build/directory.
+
=back
=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.
+
=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.
+
+=item *
+
+The order of DESTROYs has been made more predictable.
+
+=item *
+
+mkdir() now ignores trailing slashes in the directory name,
+as mandated by POSIX.
+
+=item *
+
+Attributes (like :shared) didn't work with our().
+
+=item *
+
+The PERL5OPT environment variable (for passing command line arguments
+to Perl) didn't work for more than a single group of options.
+
+=item *
+
+The tainting behaviour of sprintf() has been rationalized. It does
+not taint the result of floating point formats anymore, making the
+behaviour consistent with that of string interpolation.
+
+=item *
+
+All but the first argument of the IO syswrite() method are now optional.
+
+=item *
+
+Tie::ARRAY SPLICE method was broken.
+
+=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.
=back
+=head2 Platform Specific Changes and Fixes
+
+=over 4
+
+=item *
+
+Linux previously had problems related to sockaddrlen when using
+accept(), revcfrom() (in Perl: recv()), getpeername(), and getsockname().
+
+=item *
+
+Previously DYNIX/ptx had problems in its Configure probe for non-blocking I/O.
+
+=item *
+
+Windows
+
+=over 8
+
+=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 *
+
+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 *
+
+Duping socket handles with open(F, ">&MYSOCK") now works under Windows 9x.
+
+=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).
+
+=back
+
+=back
+
+=head1 New or Changed Diagnostics
+
+Two new debugging options have been added: if you have compiled your
+Perl with debugging, you can use the -DT and -DR options to trace
+tokenising and to add reference counts to displaying variables,
+respectively.
+
+=over 4
+
+=item *
+
+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 eval'ed
+code.
+
+=back
+
+=head1 Changed Internals
+
+=over 4
+
+=item *
+
+Some new APIs: ptr_table_clear(), ptr_table_free(), sv_setref_uv().
+For the full list of the available APIs see L<perlapi>.
+
+=item *
+
+dTHR and djSP have been obsoleted; the former removed (because it's
+a no-op) and the latter replaced with dSP.
+
+=item *
+
+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).
+
+=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
+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 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.
+
+=head2 lib/ftmp-security tests warn 'system possibly insecure'
+
+Don't panic. Read INSTALL 'make test' section instead.
+
+=head2 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 connect to "multihomed" sockets (sockets
+which have multiple IP addresses).
+
+=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.
+
=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
+hard-to-fix ways. As a stop-gap measure to avoid people from getting
+frustrated at the mysterious results (core dumps, most often) it is
+for now forbidden (you will get a fatal error even from an attempt).
+
+=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