X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=pod%2Fperldelta.pod;h=f2505e8dac579486f941b427a3504899cef87e47;hb=f7686833794ab18a8c8729b0e836f6f14223ce97;hp=f3608e9e8a4806baf776b473b5540c514aa4a685;hpb=d46b76b36bb4d867f2e17a2b4b4ae477a24e58b6;p=p5sagit%2Fp5-mst-13.2.git diff --git a/pod/perldelta.pod b/pod/perldelta.pod index f3608e9..f2505e8 100644 --- a/pod/perldelta.pod +++ b/pod/perldelta.pod @@ -1,37 +1,11 @@ =head1 NAME -perldelta - what's new for perl v5.7.0 +perldelta - what is new for perl v5.8.0 =head1 DESCRIPTION -This document describes differences between the 5.6.0 release and -the 5.7.0 release. - -=head1 Security Vulnerability Closed - -A potential security vulnerability in the optional suidperl component -of Perl has been identified. suidperl is neither built nor installed -by default. As of August the 20th, 2000, the only known vulnerable -platform is Linux, most likely all Linux distributions. CERT and -various vendors have been alerted about the vulnerability. - -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 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 -the Perl 5.7.0 release, 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/). +This document describes differences between the 5.6.0 release and the +5.8.0 release. =head1 Incompatible Changes @@ -39,14 +13,14 @@ sudo (see http://www.courtesan.com/sudo/). =item * -Arrays now always interpolate into double-quoted strings: -constructs like "foo@bar" now always assume C<@bar> is an array, -whether or not the compiler has seen use of C<@bar>. +The semantics of bless(REF, REF) were unclear and until someone proves +it to make some sense, it is forbidden. =item * -The semantics of bless(REF, REF) were unclear and until someone proves -it to make some sense, it is forbidden. +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(). =item * @@ -69,6 +43,12 @@ since it, in a way, falsely promised that the features could be used. =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. + +=item * + lstat(FILEHANDLE) now gives a warning because the operation makes no sense. In future releases this may become a fatal error. @@ -89,8 +69,96 @@ 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', ...). +=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. + +=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 +=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, +usually the system malloc on such platforms are much better optimized +for such large memory models than the Perl malloc. + +=head2 AIX Dynaloading + +The AIX dynaloading now uses in AIX releases 4.3 and newer the native +dlopen interface of AIX instead of the old emulated interface. This +change will probably break backward compatibility with compiled +modules. The change was made to make Perl more compliant with other +applications like modperl which are using the AIX native interface. + +=head2 Socket Extension Dynamic in VMS + +The Socket extension is now dynamically loaded instead of being +statically built in. This may or may not be a problem with ancient +TCP/IP stacks of VMS: we do not know since we weren't able to test +Perl in such configurations. + +=head2 Different Definition of the Unicode Character Classes \p{In...} + +As suggested by the Unicode consortium, the Unicode character classes +now prefer I as opposed to I (as defined by Unicode); +in Perl, when the C<\p{In....}> and the C<\p{In....}> regular expression +constructs are used. This has changed the definition of some of those +character classes. + +The difference between scripts and blocks is that scripts are the +glyphs used by a language or a group of languages, while the blocks +are more artificial groupings of 256 characters based on the Unicode +numbering. + +In general this change results in more inclusive Unicode character +classes, but changes to the other direction also do take place: +for example while the script C includes all the Latin +characters and their various diacritic-adorned versions, it +does not include the various punctuation or digits (since they +are not solely C). + +Changes in the character class semantics may have happened if a script +and a block happen to have the same name, for example C. +In such cases the script wins and C<\p{InHebrew}> now means the script +definition of Hebrew. The block definition in still available, +though, by appending C to the name: C<\p{InHebrewBlock}> means +what C<\p{InHebrew}> meant in perl 5.6.0. For the full list +of affected character classes, see L. + +=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 pragma interface will remain +available. + +The syntaxes C<@a->[...]> and C<@h->{...}> have now been deprecated. + +The suidperl is also considered to be too much a risk to continue +maintaining and the suidperl code is likely to be removed in a future +release. + +The C syntax (C 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 instead. + +The chdir(undef) and chdir('') behaviors to match chdir() has been +deprecated. In future versions, chdir(undef) and chdir('') will +simply fail. + =head1 Core Enhancements =over 4 @@ -102,7 +170,7 @@ in multiple arguments.) =item * -my __PACKAGE__ now works. +my __PACKAGE__ $obj now works. =item * @@ -127,450 +195,1443 @@ There is now an UNTIE method. =back -=head1 Modules and Pragmata +=head2 AUTOLOAD Is Now Lvaluable -=head2 New Modules +AUTOLOAD is now lvaluable, meaning that you can add the :lvalue attribute +to AUTOLOAD subroutines and you can assign to the AUTOLOAD return value. + +=head2 PerlIO is Now The Default =over 4 =item * -File::Temp allows one to create temporary files and directories in an -easy, portable, and secure way. +IO is now by default done via PerlIO rather than system's "stdio". +PerlIO allows "layers" to be "pushed" onto a file handle to alter the +handle's behaviour. Layers can be specified at open time via 3-arg +form of open: -=item * + open($fh,'>:crlf :utf8', $path) || ... -Storable gives persistence to Perl data structures by allowing the -storage and retrieval of Perl data to and from files in a fast and -compact binary format. +or on already opened handles via extended C: -=back + binmode($fh,':encoding(iso-8859-7)'); -=head2 Updated And Improved Modules and Pragmata +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). -=over 4 +Layers to be applied by default may be specified via the 'open' pragma. + +See L for the effects +of PerlIO on your architecture name. =item * -The following independently supported modules have been updated to -newer versions from CPAN: CGI, CPAN, DB_File, File::Spec, Getopt::Long, -the podlators bundle, Pod::LaTeX, Pod::Parser, Term::ANSIColor, Test. +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($fh,">:utf8","Uni.txt"); + +Note for EBCDIC users: the pseudo layer ":utf8" is erroneously named +for you since it's not UTF-8 what you will be getting but instead +UTF-EBCDIC. See L, L, and +http://www.unicode.org/unicode/reports/tr16/ for more information. +In future releases this naming may change. =item * -Bug fixes and minor enhancements have been applied to B::Deparse, -Data::Dumper, IO::Poll, IO::Socket::INET, Math::BigFloat, -Math::Complex, Math::Trig, Net::protoent, the re pragma, SelfLoader, -Sys::SysLog, Test::Harness, Text::Wrap, UNIVERSAL, and the warnings -pragma. +File handles can translate character encodings from/to Perl's internal +Unicode form on read/write via the ":encoding()" layer. =item * -The attributes::reftype() now works on tied arguments. +File handles can be opened to "in memory" files held in Perl scalars via: + + open($fh,'>', \$variable) || ... =item * -AutoLoader can now be disabled with C, +Anonymous temporary files are available without need to +'use FileHandle' or other module via + + open($fh,"+>", undef) || ... + +That is a literal undef, not an undefined value. =item * -The English module can now be used without the infamous performance -hit by saying +The list form of C is now implemented for pipes (at least on UNIX): - use English '-no_performance_hit'; + open($fh,"-|", 'cat', '/etc/motd') -(Assuming, of course, that one doesn't need the troublesome variables -C<$`>, C<$&>, or C<$'>.) Also, introduce C<@LAST_MATCH_START> and -C<@LAST_MATCH_END> English aliases for C<@-> and C<@+>. +creates a pipe, and runs the equivalent of exec('cat', '/etc/motd') in +the child process. =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. +The following builtin functions are now overridable: chop(), chomp(), +each(), keys(), pop(), push(), shift(), splice(), unshift(). =item * -File::Glob::glob() renamed to File::Glob::bsd_glob() to avoid -prototype mismatch with CORE::glob(). +Formats now support zero-padded decimal fields. =item * -IPC::Open3 now allows the use of numeric file descriptors. +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 * -use lib now works identically to @INC. Removing directories -with 'no lib' now works. +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 * -C<%INC> now localised in a Safe compartment so that use/require work. +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 Shell module now has an OO interface. +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 -=head1 Utility Changes +=head2 Signals Are Now Safe -=over 4 +Perl used to be fragile in that signals arriving at inopportune moments +could corrupt Perl's internal state. -=item * +=head2 Understanding of Numbers -The Emacs perl mode (emacs/cperl-mode.el) has been updated to version 4.31. +In general a lot of fixing has happened in the area of Perl's +understanding of numbers, both integer and floating point. Since in +many systems the standard number parsing functions like C +and C seem to have bugs, Perl tries to work around their +deficiencies. This results hopefully in more accurate numbers. + +=over 4 =item * -Perlbug is now much more robust. It also sends the bug report to perl.org, -not perl.com. +The rules for allowing underscores (underbars) in numeric constants +have been relaxed and simplified: now you can have an underscore +B. =item * -The perlcc utility has been rewritten and its user interface (that is, -command line) is much more like that of the UNIX C compiler, cc. +GMAGIC (right-hand side magic) could in many cases such as string +concatenation be invoked too many times. =item * -The xsubpp utility for extension writers now understands POD -documentation embedded in the *.xs files. - -=back +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. -=head1 New Documentation +=item * -=over 4 +Lexicals II: lexicals leaked at file scope into subroutines that +were declared before the lexicals. =item * -perl56delta details the changes between the 5.005 release and the -5.6.0 release. +Lvalue subroutines can now return C in list context. =item * -perldebtut is a Perl debugging tutorial. +The C and C are now exported. =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. +A new special regular expression variable has been introduced: +C<$^N>, which contains the most-recently closed group (submatch). =item * -perlnewmod tells about writing and submitting a new module. +L now supports C to change the +file timestamps to the current time. =item * -perlposix-bc explains using Perl on the POSIX-BC platform -(an EBCDIC mainframe platform). +The Perl parser has been stress tested using both random input and +Markov chain input. =item * -perlretut is a regular expression tutorial. +C now works. =item * -perlrequick is a regular expressions quick-start guide. -Yes, much quicker than perlretut. +VMS now works under PerlIO. =item * -perlutil explains the command line utilities packaged with the Perl -distribution. +END blocks are now run even if you exit/die in a BEGIN block. +The execution of END blocks is now controlled by +PL_exit_flags & PERL_EXIT_DESTRUCT_END. This enables the new +behaviour for perl embedders. This will default in 5.10. See +L. =back -=head1 Performance Enhancements +=head1 Modules and Pragmata + +=head2 New Modules =over 4 =item * -map() that changes the size of the list should now work faster. +File::Temp allows one to create temporary files and directories in an +easy, portable, and secure way. =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 quicksorts 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). -=back +Storable gives persistence to Perl data structures by allowing the +storage and retrieval of Perl data to and from files in a fast and +compact binary format. -=head1 Installation and Configuration Improvements +=item * -=head2 Generic Improvements +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. -=over 4 +See L for more information. =item * -INSTALL now explains how you can configure perl to use 64-bit -integers even on non-64-bit platforms. +Class::ISA, by Sean Burke, for reporting the search path for a +class's ISA tree, has been added. + +See L for more information. =item * -Policy.sh policy change: if you are reusing a Policy.sh file (see -INSTALL) and you use Configure -Dprefix=/foo/bar and in the old -Policy $prefix eq $siteprefix and $prefix eq $vendorprefix, all of -them will now be changed to the new prefix, /foo/bar. (Previously -only $prefix changed.) If you do not like this new behaviour, -specify prefix, siteprefix, and vendorprefix explicitly. +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 * -A new optional location for Perl libraries, otherlibdirs, is available. -It can be used for example for vendor add-ons without disturbing Perl's -own library directories. +Digest, a frontend module for calculating digests (checksums), +from Gisle Aas, has been added. + +See L for more information. =item * -In many platforms the vendor-supplied 'cc' is too stripped-down to -build Perl (basically, 'cc' doesn't do ANSI C). If this seems -to be the case and 'cc' does not seem to be the GNU C compiler -'gcc', an automatic attempt is made to find and use 'gcc' instead. +Digest::MD5 for calculating MD5 digests (checksums), by Gisle Aas, +has been added. -=item * + use Digest::MD5 'md5_hex'; -gcc needs to closely track the operating system release to avoid -build problems. If Configure finds that gcc was built for a different -operating system release than is running, it now gives a clearly visible -warning that there may be trouble ahead. + $digest = md5_hex("Thirsty Camel"); -=item * + print $digest, "\n"; # 01d19d9d2045e005c3f1b80e8b164de1 -If binary compatibility with the 5.005 release is not wanted, Configure -no longer suggests including the 5.005 modules in @INC. +NOTE: the MD5 backward compatibility module is deliberately not +included since its use is discouraged. + +See L for more information. =item * -Configure C<-S> can now run non-interactively. +Encode, by Nick Ing-Simmons, provides a mechanism to translate +between different character encodings. Support for Unicode, +ISO-8859-*, ASCII, CP*, KOI8-R, and three variants of EBCDIC are +compiled in to the module. Several other encodings (like Japanese, +Chinese, and MacIntosh encodings) are included and will be loaded at +runtime. -=item * +Any encoding supported by Encode module is also available to the +":encoding()" layer if PerlIO is used. -configure.gnu now works with options with whitespace in them. +See L for more information. =item * -installperl now outputs everything to STDERR. +Filter::Simple is an easy-to-use frontend to Filter::Util::Call, +from Damian Conway. -=item * + # in MyFilter.pm: -$Config{byteorder} is now computed dynamically (this is more robust -with "fat binaries" where an executable image contains binaries for -more than one binary platform.) + package MyFilter; -=back + use Filter::Simple sub { + while (my ($from, $to) = splice @_, 0, 2) { + s/$from/$to/g; + } + }; -=head1 Selected Bug Fixes + 1; -=over 4 + # in user's code: -=item * + use MyFilter qr/red/ => 'green'; -Several debugger fixes: exit code now reflects the script exit code, -condition C<"0"> now treated correctly, the C command now checks -line number, the C<$.> no longer gets corrupted, all debugger output now -goes correctly to the socket if RemotePort is set. + print "red\n"; # this code is filtered, will print "green\n" + print "bored\n"; # this code is filtered, will print "bogreen\n" -=item * + no MyFilter; -C<*foo{FORMAT}> now works. + print "red\n"; # this code is not filtered, will print "red\n" + +See L for more information. =item * -Lexical warnings now propagating correctly between scopes. +Filter::Util::Call, by Paul Marquess, provides you with the +framework to write I in Perl. For most uses +the frontend Filter::Simple is to be preferred. +See L for more information. =item * -Line renumbering with eval and C<#line> now works. +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. -=item * + use Locale::Country; -Fixed numerous memory leaks, especially in eval "". + $country = code2country('jp'); # $country gets 'Japan' + $code = country2code('Norway'); # $code gets 'no' + +See L, L, L, +and L for more information. =item * -Modulus of unsigned numbers now works (4063328477 % 65535 used to -return 27406, instead of 27047). +MIME::Base64, by Gisle Aas, allows you to encode data in base64. -=item * + use MIME::Base64; -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. + $encoded = encode_base64('Aladdin:open sesame'); + $decoded = decode_base64($encoded); -=item * + print $encoded, "\n"; # "QWxhZGRpbjpvcGVuIHNlc2FtZQ==" -our() variables will not cause "will not stay shared" warnings. +See L for more information. =item * -pack "Z" now correctly terminates the string with "\0". +MIME::QuotedPrint, by Gisle Aas, allows you to encode data in +quoted-printable encoding. -=item * + use MIME::QuotedPrint; -Fix password routines which in some shadow password platforms -(e.g. HP-UX) caused getpwent() to return every other entry. + $encoded = encode_qp("Smiley in Unicode: \x{263a}"); + $decoded = decode_qp($encoded); -=item * + print $encoded, "\n"; # "Smiley in Unicode: =263A" -printf() no longer resets the numeric locale to "C". +MIME::QuotedPrint has been enhanced to provide the basic methods +necessary to use it with PerlIO::Via as in : -=item * + use MIME::QuotedPrint; + open($fh,">Via(MIME::QuotedPrint)",$path) -C now parses correctly as C<'a\\b'>. +See L for more information. =item * -Printing quads (64-bit integers) with printf/sprintf now works -without the q L ll prefixes (assuming you are on a quad-capable platform). +PerlIO::Scalar, by Nick Ing-Simmons, provides the implementation of +IO to "in memory" Perl scalars as discussed above. It also serves as +an example of a loadable layer. Other future possibilities include +PerlIO::Array and PerlIO::Code. See L for more +information. =item * -Regular expressions on references and overloaded scalars now work. +PerlIO::Via, by Nick Ing-Simmons, acts as a PerlIO layer and wraps +PerlIO layer functionality provided by a class (typically implemented +in perl code). -=item * + use MIME::QuotedPrint; + open($fh,">Via(MIME::QuotedPrint)",$path) -scalar() now forces scalar context even when used in void context. +This will automatically convert everything output to C<$fh> +to Quoted-Printable. See L for more information. =item * - -sort() arguments are now compiled in the right wantarray context -(they were accidentally using the context of the sort() itself). + +Pod::Text::Overstrike, by Joe Smith, has been added. +It converts POD data to formatted overstrike text. +See L for more information. =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). +Switch from Damian Conway has been added. Just by saying -=item * + use Switch; -$AUTOLOAD, sort(), lock(), and spawning subprocesses -in multiple threads simultaneously are now thread-safe. +you have C and C available in Perl. -=item * + use Switch; -Allow read-only string on left hand side of non-modifying tr///. + switch ($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 for more information. =item * -Several Unicode fixes (but still not perfect). +Text::Balanced from Damian Conway has been added, for +extracting delimited text sequences from strings. -=over 8 + use Text::Balanced 'extract_delimited'; -=item * + ($a, $b) = extract_delimited("'never say never', he never said", "'", ''); -BOMs (byte order marks) in the beginning of Perl files -(scripts, modules) should now be transparently skipped. -UTF16 encoded Perl files should now be read correctly. +$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 for more information. =item * -The character tables have been updated to new Unicode 3.0 features. +Tie::RefHash::Nestable, by Edward Avis, allows storing hash references +(unlike the standard Tie::RefHash) The module is contained within +Tie::RefHash. =item * -chr() for values greater than 127 now create utf8 when under use -utf8. +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. =item * -Comparing with utf8 data does not magically upgrade non-utf8 data into -utf8. +L - Simpler definition of attribute handlers =item * -C, C, and C now match titlecase. +L - generate XS code to import C header constants =item * -Concatenation with the C<.> operator or via variable interpolation, -C, C, C, C, the C operator, -substitution with C, single-quoted UTF8, should now work--in -theory. +L - query locale information =item * -The C operator now works I better but is still rather -broken. Note that the C functionality has been removed (but -see pack('U0', ...)). +L - functions for dealing with RFC3066-style language tags =item * -Zero entries were missing from the Unicode classes like C. +L - a collection of perl5 modules related to network programming -=back +Perl installation leaves libnet unconfigured, use F to configure. =item * -UNIVERSAL::isa no longer caches methods incorrectly. (This broke -the Tk extension with 5.6.0.) - -=back +L - selection of general-utility list subroutines -=head2 Platform Specific Changes and Fixes +=item * -=over 4 +L - framework for localization =item * -BSDI 4.* - -Perl now works on post-4.0 BSD/OSes. +L - Make your functions faster by trading space for time =item * -All BSDs - -Setting C<$0> now works (as much as possible; see perlvar for details). +L - pseudo-class for method redispatch =item * -Cygwin - -Numerous updates; currently synchronised with Cygwin 1.1.4. +L - selection of general-utility scalar subroutines =item * -EPOC - -EPOC update after Perl 5.6.0. See README.epoc. +L - yet another framework for writing test scripts =item * -FreeBSD 3.* - -Perl now works on post-3.0 FreeBSDs. +L - Basic utilities for writing tests =item * -HP-UX - -README.hpux updated; C now almost works. +L - high resolution ualarm, usleep, and gettimeofday =item * -IRIX +L - Object Oriented time objects -Numerous compilation flag and hint enhancements; accidental mixing -of 32-bit and 64-bit libraries (a doomed attempt) made much harder. +(Previously known as L.) =item * -Linux - -Long doubles should now work (see INSTALL). +L - a simple API to convert seconds to other date values + +=item * + +L - Unicode Character Database + +=back + +=head2 Updated And Improved Modules and Pragmata + +=over 4 + +=item * + +The following independently supported modules have been updated to +newer versions from CPAN: CGI, CPAN, DB_File, File::Spec, Getopt::Long, +the podlators bundle, Pod::LaTeX, Pod::Parser, Term::ANSIColor, Test. + +=item * + +Bug fixes and minor enhancements have been applied to B::Deparse, +Data::Dumper, IO::Poll, IO::Socket::INET, Math::BigFloat, +Math::Complex, Math::Trig, Net::protoent, the re pragma, SelfLoader, +Sys::SysLog, Test::Harness, Text::Wrap, UNIVERSAL, and the warnings +pragma. + +=item * + +The attributes::reftype() now works on tied arguments. + +=item * + +AutoLoader can now be disabled with C, + +=item * + +The English module can now be used without the infamous performance +hit by saying + + use English '-no_performance_hit'; + +(Assuming, of course, that one doesn't need the troublesome variables +C<$`>, C<$&>, or C<$'>.) Also, introduced C<@LAST_MATCH_START> and +C<@LAST_MATCH_END> English aliases for C<@-> and C<@+>. + +=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 * + +File::Glob::glob() renamed to File::Glob::bsd_glob() to avoid +prototype mismatch with CORE::glob(). + +=item * + +IPC::Open3 now allows the use of numeric file descriptors. + +=item * + +use lib now works identically to @INC. Removing directories +with 'no lib' now works. + +=item * + +C<%INC> now localised in a Safe compartment so that use/require work. + +=item * + +The Shell module now has an OO interface. + +=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 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. + +=item * + +L module has been significantly enhanced. It now +can deparse almost all of the standard test suite (so that the +tests still succeed). There is a make target "test.deparse" +for trying this out. + +=item * + +L now assigns the array/hash element if the accessor +is called with an array/hash element as the B argument. + +=item * + +L extension is now (even) faster. + +=item * + +L extension has been updated to version 1.77. + +=item * + +L, L, and L have been rewritten to use the +new-style constant dispatch section (see L). + +=item * + +L is now (again) reentrant. It also has been made +more portable. + +=item * + +L now supports C constant to limit the +size of the returned list of filenames. + +=item * + +L now supports C of zero (usually meaning +that the operating system will make one up.) + +=item * + +The L pragma now supports declaring fully qualified variables. +(Something that C does not and will not support.) + +=back + +=head1 Utility Changes + +=over 4 + +=item * + +The Emacs perl mode (emacs/cperl-mode.el) has been updated to version +4.31. + +=item * + +Perlbug is now much more robust. It also sends the bug report to +perl.org, not perl.com. + +=item * + +The perlcc utility has been rewritten and its user interface (that is, +command line) is much more like that of the UNIX C compiler, cc. + +=item * + +The xsubpp utility for extension writers now understands POD +documentation embedded in the *.xs files. + +=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. + +=item * + +The F is now much faster. + +=item * + +L now supports C trigraphs. + +=item * + +L uses the new L module which will affect +newly created extensions that define constants. Since the new code is +more correct (if you have two constants where the first one is a +prefix of the second one, the first constant B gets defined), +less lossy (it uses integers for integer constant, as opposed to the +old code that used floating point numbers even for integer constants), +and slightly faster, you might want to consider regenerating your +extension code (the new scheme makes regenerating easy). +L now also supports C trigraphs. + +=item * + +L has been added to configure the libnet. + +=item * + +The F (and thusly L) now allows specifying +a cache directory. + +=back + +=head1 New Documentation + +=over 4 + +=item * + +perl56delta details the changes between the 5.005 release and the +5.6.0 release. + +=item * + +perldebtut is a Perl debugging tutorial. + +=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 * + +perlnewmod tells about writing and submitting a new module. + +=item * + +perlposix-bc explains using Perl on the POSIX-BC platform +(an EBCDIC mainframe platform). + +=item * + +perlretut is a regular expression tutorial. + +=item * + +perlrequick is a regular expressions quick-start guide. +Yes, much quicker than perlretut. + +=item * + +perlutil explains the command line utilities packaged with the Perl +distribution. + +=back + +=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. + +=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. + +=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. + +=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. + +=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. + +=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. + +=head2 Porting/repository.pod + +Documentation on how to use the Perl source repository has been added. + +=over 4 + +=item * + +L is an article about software localization, +originally published in The Perl Journal #13, republished here with +kind permission. + +=item * + +More README.$PLATFORM files have been converted into pod, which also +means that they also be installed as perl$PLATFORM documentation +files. The new files are L, L, L, +L, L, L, L, L, +and L. + +=item * + +The F and F files have been merged into L. + +=item * + +Use of the F tool to profile Perl has been documented in +L. There is a make target "perl.gprof" for generating a +gprofiled Perl executable. + +=back + +=head1 Performance Enhancements + +=over 4 + +=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). + +=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 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 Installation and Configuration Improvements + +=head2 Generic Improvements + +=over 4 + +=item * + +INSTALL now explains how you can configure Perl to use 64-bit +integers even on non-64-bit platforms. + +=item * + +Policy.sh policy change: if you are reusing a Policy.sh file +(see INSTALL) and you use Configure -Dprefix=/foo/bar and in the old +Policy $prefix eq $siteprefix and $prefix eq $vendorprefix, all of +them will now be changed to the new prefix, /foo/bar. (Previously +only $prefix changed.) If you do not like this new behaviour, +specify prefix, siteprefix, and vendorprefix explicitly. + +=item * + +A new optional location for Perl libraries, otherlibdirs, is available. +It can be used for example for vendor add-ons without disturbing Perl's +own library directories. + +=item * + +In many platforms the vendor-supplied 'cc' is too stripped-down to +build Perl (basically, 'cc' doesn't do ANSI C). If this seems +to be the case and 'cc' does not seem to be the GNU C compiler +'gcc', an automatic attempt is made to find and use 'gcc' instead. + +=item * + +gcc needs to closely track the operating system release to avoid +build problems. If Configure finds that gcc was built for a different +operating system release than is running, it now gives a clearly visible +warning that there may be trouble ahead. + +=item * + +If binary compatibility with the 5.005 release is not wanted, Configure +no longer suggests including the 5.005 modules in @INC. + +=item * + +Configure C<-S> can now run non-interactively. + +=item * + +configure.gnu now works with options with whitespace in them. + +=item * + +installperl now outputs everything to STDERR. + +=item * + +$Config{byteorder} is now computed dynamically (this is more robust +with "fat binaries" where an executable image contains binaries for +more than one binary platform.) + +=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 for more information about pixie and +Third Degree. + +=item * + +In AFS installations one can configure the root of the AFS to be +somewhere else than the default F by using the Configure +parameter C<-Dafsroot=/some/where/else>. + +=item * + +The version of Berkeley DB used when the Perl (and, presumably, the +DB_File extension) was built is now available as +C<@Config{qw(db_version_major db_version_minor db_version_patch)}> +from Perl and as C from C. + +=item * + +The Thread extension is now not built at all under ithreads +(C) because it wouldn't work anyway (the +Thread extension requires being Configured with C<-Duse5005threads>). + +=item * + +The C compiler backend has been so significantly improved +that almost the whole Perl test suite passes after being deparsed. A +make target has been added to help in further testing: C. + +=back + +=head2 New Or Improved Platforms + +For the list of platforms known to support Perl, +see L. + +=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, +L (for POSIX-BC), and L 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 * + +MacOS 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. + +=item * + +AIX should now work better with gcc, threads, and 64-bitness. Also the +long doubles support in AIX should be better now. See L. + +=item * + +AtheOS (http://www.atheos.cx/) is a new platform. + +=item * + +DG/UX platform now supports the 5.005-style threads. See L. + +=item * + +DYNIX/ptx platform (a.k.a. dynixptx) is supported at or near osvers 4.5.2. + +=item * + +Several MacOS (Classic) portability patches have been applied. We +hope to get a fully working port by 5.8.0. (The remaining problems +relate to the changed IO model of Perl.) See L. + +=item * + +MacOS X (or Darwin) should now be able to build Perl even on HFS+ +filesystems. (The case-insensitivity confused the Perl build process.) + +=item * + +NetWare from Novell is now supported. See L. + +=item * + +The Amdahl UTS UNIX mainframe platform is now supported. + +=back + +=head1 Selected Bug Fixes + +=over 4 + +=item * + +Several debugger fixes: exit code now reflects the script exit code, +condition C<"0"> now treated correctly, the C command now checks +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. + +=item * + +Lexical warnings now propagating correctly between scopes. + +=item * + +Line renumbering with eval and C<#line> now works. + +=item * + +Fixed numerous memory leaks, especially in eval "". + +=item * + +Modulus of unsigned numbers now works (4063328477 % 65535 used to +return 27406, instead of 27047). + +=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. + +=item * + +our() variables will not cause "will not stay shared" warnings. + +=item * + +pack "Z" now correctly terminates the string with "\0". + +=item * + +Fix password routines which in some shadow password platforms +(e.g. HP-UX) caused getpwent() to return every other entry. + +=item * + +printf() no longer resets the numeric locale to "C". + +=item * + +C now parses correctly as C<'a\\b'>. + +=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). + +=item * + +Regular expressions on references and overloaded scalars now work. + +=item * + +scalar() now forces scalar context even when used in void context. + +=item * + +sort() arguments are now compiled in the right wantarray context +(they were accidentally using the context of the sort() itself). + +=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). + +=item * + +$AUTOLOAD, sort(), lock(), and spawning subprocesses +in multiple threads simultaneously are now thread-safe. + +=item * + +Allow read-only string on left hand side of non-modifying tr///. + +=item * + +Several Unicode fixes (but still not perfect). + +=over 8 + +=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. + +=item * + +The character tables have been updated to Unicode 3.0.1. + +=item * + +chr() for values greater than 127 now create utf8 when under use +utf8. + +=item * + +Comparing with utf8 data does not magically upgrade non-utf8 data into +utf8. + +=item * + +C, C, and C now match titlecase. + +=item * + +Concatenation with the C<.> operator or via variable interpolation, +C, C, C, C, the C operator, +substitution with C, single-quoted UTF8, should now work--in +theory. + +=item * + +The C operator now works I better but is still rather +broken. Note that the C functionality has been removed (but +see pack('U0', ...)). + +=item * + +vec() now refuses to deal with characters >255. + +=item * + +Zero entries were missing from the Unicode classes like C. + +=back + +=item * + +UNIVERSAL::isa no longer caches methods incorrectly. (This broke +the Tk extension with 5.6.0.) + +=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 * + +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 /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. + +=back + +=head2 Platform Specific Changes and Fixes + +=over 4 + +=item * + +BSDI 4.* + +Perl now works on post-4.0 BSD/OSes. + +=item * + +All BSDs + +Setting C<$0> now works (as much as possible; see perlvar for details). + +=item * + +Cygwin + +Numerous updates; currently synchronised with Cygwin 1.1.4. + +=item * + +EPOC + +EPOC update after Perl 5.6.0. See README.epoc. + +=item * + +FreeBSD 3.* + +Perl now works on post-3.0 FreeBSDs. + +=item * + +HP-UX + +README.hpux updated; C now almost works. + +=item * + +IRIX + +Numerous compilation flag and hint enhancements; accidental mixing +of 32-bit and 64-bit libraries (a doomed attempt) made much harder. + +=item * + +Linux + +Long doubles should now work (see INSTALL). =item * @@ -671,12 +1732,12 @@ Fake signal handling reenabled, bugs and all. =item * Less stack reserved per thread so that more threads can run -concurrently. (still 16M perl thread) +concurrently. (Still 16M per thread.) =item * Ctmpdir()> now prefers C:/temp over /tmp -(works better when perl running as service). +(works better when perl is running as service). =item * @@ -692,6 +1753,8 @@ winsock handle leak fixed. =back +=back + =head1 New or Changed Diagnostics All regular expression compilation error messages are now hopefully @@ -706,6 +1769,26 @@ for example C instead of . The "Unrecognized escape" warning has been extended to include C<\8>, C<\9>, and C<\_>. There is no need to escape any of the C<\w> characters. +=over 4 + +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. + +=item * + +If an attempt to use a (non-blessed) reference as an array index +is made, a warning is given. + +=item * + +C and C (with no values to push or unshift) +now give a warning. This may be a problem for generated and evaled +code. + +=back + =head1 Changed Internals =over 4 @@ -721,8 +1804,8 @@ You can now build a really minimal perl called microperl. Building microperl does not require even running Configure; C should be enough. Beware: microperl makes many assumptions, some of which may be too bold; the resulting -executable may crash or otherwise misbehave in wondrous ways. For -careful hackers only. +executable may crash or otherwise misbehave in wondrous ways. +For careful hackers only. =item * @@ -740,103 +1823,501 @@ Added is_utf8_char(), is_utf8_string(), bytes_to_utf8(), and utf8_to_bytes(). 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. + +=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 Known Problems +=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 November 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 +Perl 5.8.0 (and the maintenance release 5.6.1, and it was removed also +from all the Perl 5.7 releases), 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/). -=head2 Unicode Support Still Far From Perfect +=head1 Selected Bug Fixes -We're working on it. Stay tuned. +Numerous memory leaks and uninitialized memory accesses have been hunted down. +Most importantly anonymous subs used to leak quite a bit. -=head2 EBCDIC Still A Lost Platform +=over 4 -The plan is to bring them back. +=item * -=head2 Building Extensions Can Fail Because Of Largefiles +chop(@list) in list context returned the characters chopped in +reverse order. This has been reversed to be in the right order. -Certain extensions like mod_perl and BSD::Resource 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. +=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. + +=item * + +The autouse pragma didn't work for Multi::Part::Function::Names. + +=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 * + +L -R didn't work. + +=item * + +PERL5OPT with embedded spaces didn't work. + +=item * + +L ignored the C constant. + +=back + +=head2 Platform Specific Changes and Fixes + +=over 4 + +=item * -=head2 ftmp-security tests warn 'system possibly insecure' +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. -Don't panic. Read INSTALL 'make test' section instead. +=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). -=head2 Long Doubles Still Don't Work In Solaris +=back + +=head1 New Tests -The experimental long double support is still very much so in Solaris. -(Other platforms like Linux and Tru64 are beginning to solidify in -this area.) +Several new tests have been added, especially for the F subsection. -=head2 Storable tests fail in some platforms +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 +to be closer to the library/extension they are testing.) -If any Storable tests fail the use of Storable is not advisable. +=head1 New or Changed Diagnostics =over 4 =item * -Many Storable tests fail on AIX configured with 64 bit integers. +In the regular expression diagnostics the CE HERE> marker +introduced in 5.7.0 has been changed to be C-- HERE> since too +many people found the CE> to be too similar to here-document +starters. + +=item * + +If you try to L a number less than 0 or larger than 255 +using the C<"C"> format you will get an optional warning. Similarly +for the C<"c"> format and a number less than -128 or more than 127. + +=item * + +Certain regex modifiers such as C<(?o)> make sense only if applied to +the entire regex. You will an optional warning if you try to do otherwise. + +=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. + +=back + +=head1 Source Code Enhancements + +=head2 MAGIC constants -So far unidentified problems break Storable in AIX if Perl is -configured to use 64 bit integers. AIX in 32-bit mode works and -other 64-bit platforms work with Storable. +The MAGIC constants (e.g. C<'P'>) have been macrofied +(e.g. C) for better source code readability +and maintainability. + +=head2 Better commented code + +F, F, and F have now been extensively commented. + +=head2 Regex pre-/post-compilation items matched up + +The regex compiler now maintains a structure that identifies nodes in +the compiled bytecode with the corresponding syntactic features of the +original regex expression. The information is attached to the new +C member of the C. See L for more +complete information. + +=head2 gcc -Wall + +The C code has been made much more C clean. Some warning +messages still remain, though, so if you are compiling with gcc you +will see some warnings about dubious practices. The warnings are +being worked on. + +=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 =item * -DOS DJGPP may hang when testing Storable. +In AIX 4.2 Perl extensions that use C++ functions that use statics +may have problems in that the statics are not getting initialized. +In newer AIX releases this has been solved by linking Perl with +the libC_r library, but unfortunately in AIX 4.2 the said library +has an obscure bug where the various functions related to time +(such as time() and gettimeofday()) return broken values, and +therefore in AIX 4.2 Perl is not linked against the libC_r. + +=item * + +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. + +=back + +=head2 Amiga Perl Invoking Mystery + +One cannot call Perl using the C syntax, that is, C +works, but for example C doesn't. The exact reason is +known but the current suspect is the F library. + +=head2 lib/ftmp-security tests warn 'system possibly insecure' + +Don't panic. Read INSTALL 'make test' section instead. + +=head2 Cygwin intermittent failures of lib/Memoize/t/expire_file 11 and 12 + +The subtests 11 and 12 sometimes fail and sometimes work. + +=head2 HP-UX lib/io_multihomed Fails When LP64-Configured + +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 HP-UX lib/posix Subtest 9 Fails When LP64-Configured + +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 Linux With Sfio Fails op/misc Test 48 + +No known fix. + +=head2 OS/390 + +OS/390 has rather many test failures but the situation is actually +better than it was in 5.6.0, it's just that so many new modules and +tests have been added. + + Failed Test Stat Wstat Total Fail Failed List of Failed + ----------------------------------------------------------------------------- + ../ext/B/Deparse.t 14 1 7.14% 14 + ../ext/B/Showlex.t 1 1 100.00% 1 + ../ext/Encode/Encode/Tcl.t 610 13 2.13% 592 594 596 598 + 600 602 604-610 + ../ext/IO/lib/IO/t/io_unix.t 113 28928 5 3 60.00% 3-5 + ../ext/POSIX/POSIX.t 29 1 3.45% 14 + ../ext/Storable/t/lock.t 255 65280 5 3 60.00% 3-5 + ../lib/locale.t 129 33024 117 19 16.24% 99-117 + ../lib/warnings.t 434 1 0.23% 75 + ../lib/ExtUtils.t 27 1 3.70% 25 + ../lib/Math/BigInt/t/bigintpm.t 1190 1 0.08% 1145 + ../lib/Unicode/UCD.t 81 48 59.26% 1-16 49-64 66-81 + ../lib/User/pwent.t 9 1 11.11% 4 + op/pat.t 660 6 0.91% 242-243 424-425 + 626-627 + op/split.t 0 9 ?? ?? % ?? + op/taint.t 174 3 1.72% 156 162 168 + op/tr.t 70 3 4.29% 50 58-59 + Failed 16/422 test scripts, 96.21% okay. 105/23251 subtests failed, 99.55% okay. + +=head2 op/sprintf tests 129 and 130 + +The op/sprintf tests 129 and 130 are known to fail on some platforms. +Examples include any platform using sfio, and Compaq/Tandem's NonStop-UX. +The failing platforms do not comply with the ANSI C Standard, line +19ff on page 134 of ANSI X3.159 1989 to be exact. (They produce +something other 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 + +B + +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 + +=head2 UNICOS + +=over 4 =item * -st-06compat fails in UNICOS and UNICOS/mk. +ext/POSIX/sigaction subtests 6 and 13 may fail. + +=item * -This means that you cannot read old (pre-Storable-0.7) Storable images -made in other platforms. +lib/ExtUtils may spuriously claim that subtest 28 failed, +which is interesting since the test only has 27 tests. =item * -st-store.t and st-retrieve may fail with Compaq C 6.2 on OpenVMS Alpha 7.2. +Numerous numerical test failures + + op/numconvert 209,210,217,218 + op/override 7 + ext/Time/HiRes/HiRes 9 + lib/Math/BigInt/t/bigintpm 1145 + lib/Math/Trig 25 + +These tests fail because of yet unresolved floating point inaccuracies. + +=back + +=head2 UTS + +There are a few known test failures, see L. -=head2 Threads Are Still Experimental +=head2 VMS -Multithreading is still an experimental feature. Some platforms -emit the following message for lib/thr5005 +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. - # - # This is a KNOWN FAILURE, and one of the reasons why threading - # is still an experimental feature. It is here to stop people - # from deploying threads in production. ;-) - # +Here are the known failures from some compiler/platform combinations. + +DEC C V5.3-006 on OpenVMS VAX V6.2 -and another known warning is - - pragma/overload......Unbalanced saves: 3 more saves than restores - panic: magic_mutexfree during global destruction. - ok - lib/selfloader.......Unbalanced saves: 3 more saves than restores - panic: magic_mutexfree during global destruction. - ok - lib/st-dclone........Unbalanced saves: 3 more saves than restores - panic: magic_mutexfree during global destruction. - ok + [-.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. + +=head2 Win32 + +In multi-CPU boxes there are some problems with the I/O buffering: +some output may appear twice. + +=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 Variable Attributes are not Currently Usable for Tieing + +This limitation will hopefully be fixed in future. (Subroutine +attributes work fine for tieing, see L). + +=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 yet. -The backend part that has seen perhaps the most progress is the -bytecode compiler. +The compiler suite is slowly getting better but is nowhere near +working order yet. -=back +=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 +experimental. The implementations of long doubles are not yet +widespread and the existing implementations are not quite mature +or standardised, therefore trying to support them is a rare +and moving target. The gain of more precision may also be offset +by slowdown in computations (more bits to move around, and the +operations are more likely to be executed by less optimised +libraries). =head1 Reporting Bugs @@ -863,9 +2344,6 @@ The F and F files for copyright information. =head1 HISTORY -Written by Jarkko Hietaniemi >, with many contributions -from The Perl Porters and Perl Users submitting feedback and patches. - -Send omissions or corrections to >. +Written by Jarkko Hietaniemi >. =cut