X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=pod%2Fperldelta.pod;h=fa4a67e9393131169f36632d9ade0313e57abb8a;hb=a0acbdc36d211b2eba42328df555d9ec49fa4cd4;hp=45b2f8ede286bcaf7c36b6e96f41d3ba733b8a94;hpb=d764f01a54c0f82174c22184bb83b9dca8be1913;p=p5sagit%2Fp5-mst-13.2.git diff --git a/pod/perldelta.pod b/pod/perldelta.pod index 45b2f8e..fa4a67e 100644 --- a/pod/perldelta.pod +++ b/pod/perldelta.pod @@ -1,103 +1,926 @@ =head1 NAME -perldelta - what's new for perl v5.8.0 +perldelta - what's new for perl v5.7.0 =head1 DESCRIPTION -This document describes differences between the 5.6 release and this one. +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 September the 2nd, 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 +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 +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/). + +=head1 Incompatible Changes + +=over 4 + +=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>. + +=item * + +The semantics of bless(REF, REF) were unclear and until someone proves +it to make some sense, it is forbidden. + +=item * + +A reference to a reference now stringify as "REF(0x81485ec)" instead +of "SCALAR(0x81485ec)" in order to be more consistent with the return +value of ref(). + +=item * + +The very dusty examples in the eg/ directory have been removed. +Suggestions for new shiny examples welcome but the main issue is that +the examples need to be documented, tested and (most importantly) +maintained. + +=item * + +The obsolete chat2 library that should never have been allowed +to escape the laboratory has been decommissioned. + +=item * + +The unimplemented POSIX regex features [[.cc.]] and [[=c=]] are still +recognised but now cause fatal errors. The previous behaviour of +ignoring them by default and warning if requested was unacceptable +since it, in a way, falsely promised that the features could be used. + +=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. + +=item * + +The long deprecated uppercase aliases for the string comparison +operators (EQ, NE, LT, LE, GE, GT) have now been removed. + +=item * + +The regular expression captured submatches ($1, $2, ...) are now +more consistently unset if the match fails, instead of leaving false +data lying around in them. + +=item * + +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. + +=back =head1 Core Enhancements +=over 4 + +=item * + +Formats now support zero-padded decimal fields. + +=item * + +C now works (previously one couldn't pass +in multiple arguments.) + +=item * + +my __PACKAGE__ now works. + +=item * + +C now works even if there is no "sub unimport" in the Module. + +=item * + +The numerical comparison operators return C if either operand +is a NaN. Previously the behaviour was unspecified. + +=item * + +C can now be used to force a string to UTF8. + +=item * + +The printf and sprintf now support parameter reordering using the +C<%\d+\$> and C<*\d+\$> syntaxes. + +=item * + +prototype(\&) is now available. + +=item * + +There is now an UNTIE method. + +=back + =head1 Modules and Pragmata +=head2 New Modules + +=over 4 + +=item * + +File::Temp allows one to create temporary files and directories in an +easy, portable, and secure way. + +=item * + +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. + +=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. + +=back + =head1 Utility Changes -=head1 Improved Documentation +=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. + +=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. -=head1 Performance enhancements +=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 + +=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. 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. + + +=back =head1 Installation and Configuration Improvements -=head2 gcc automatically tried if 'cc' does not seem to be working +=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, the 'cc' doesn't do ANSI C). If this seems -to be the case and the 'cc' does not seem to be the GNU C compiler +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. -=head1 Platform specific changes +=item * -=head2 printf() and sprintf() give two-digit exponent where possible +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. -Perl's printf() and sprintf() use the standard C library sprintf() -function to implement the floating point conversions provided by the -C<%e>, C<%f> and C<%g> formats (and their upper-case counterparts). C -library sprintf() functions vary in the number of exponent digits that -they produce in scientific notation when the modulus of the exponent -is less than one hundred: most platforms give two digits (for example, -C<1.234e-45>) while others, notably Microsoft's libraries for Windows, -give three (as in C<1.234e-045>). Previously, Perl's functions -produced results identical to the platform's underlying library -function, resulting in script portability problems. Now, on all -platforms, only two exponent digits are delivered unless more are -needed. +=item * -Note that this change applies only to explicit conversions made by -printf() and sprintf(); implicit conversions still show the same -behavior as the underlying library function: +If binary compatibility with the 5.005 release is not wanted, Configure +no longer suggests including the 5.005 modules in @INC. - print "native: ", 1234567e89, sprintf("; standardized: %e\n", 1234567e89) +=item * -outputs +Configure C<-S> can now run non-interactively. - native: 1.234567e+95; standardized: 1.234567e+95 +=item * -on most platforms, and +configure.gnu now works with options with whitespace in them. - native: 1.234567e+095; standardized: 1.234567e+95 +=item * -on the remainder. +installperl now outputs everything to STDERR. -=head1 Significant bug fixes +=item * -=head1 New or Changed Diagnostics +$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 * + +Configure no longer included the DBM libraries (dbm, gdbm, db, ndbm) +when building the Perl binary. The only exception to this is SunOS 4.x, +which needs them. + +=back + +=head1 Selected Bug Fixes =over 4 -=item (perhaps you forgot to load "%s"?) +=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. -(F) This is an educated guess made in conjunction with the message -"Can't locate object method \"%s\" via package \"%s\"". It often means -that a method requires a package that has not been loaded. +=item * -=item Ambiguous range in transliteration operator +scalar() now forces scalar context even when used in void context. -(F) You wrote something like C which doesn't mean anything at -all. To include a C<-> character in a transliteration, put it either -first or last. (In the past, C was synonymous with -C, which was probably not what you would have expected.) +=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 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 * + +Zero entries were missing from the Unicode classes like C. =back -=head1 New tests +=item * -=head1 Incompatible Changes +UNIVERSAL::isa no longer caches methods incorrectly. (This broke +the Tk extension with 5.6.0.) + +=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 * + +MacOS Classic + +Compilation of the standard Perl distribution in MacOS Classic should +now work if you have the Metrowerks development environment and +the missing Mac-specific toolkit bits. Contact the macperl mailing +list for details. + +=item * + +MPE/iX + +MPE/iX update after Perl 5.6.0. See README.mpeix. + +=item * + +NetBSD/sparc + +Perl now works on NetBSD/sparc. + +=item * + +OS/2 + +Now works with usethreads (see INSTALL). + +=item * + +Solaris + +64-bitness using the Sun Workshop compiler now works. + +=item * + +Tru64 (aka Digital UNIX, aka DEC OSF/1) + +The operating system version letter now recorded in $Config{osvers}. +Allow compiling with gcc (previously explicitly forbidden). Compiling +with gcc still not recommended because buggy code results, even with +gcc 2.95.2. + +=item * + +Unicos + +Fixed various alignment problems that lead into core dumps either +during build or later; no longer dies on math errors at runtime; +now using full quad integers (64 bits), previously was using +only 46 bit integers for speed. + +=item * + +VMS + +chdir() now works better despite a CRT bug; now works with MULTIPLICITY +(see INSTALL); now works with Perl's malloc. + +=item * + +Windows + +=over 8 + +=item * + +accept() no longer leaks memory. + +=item * + +Better chdir() return value for a non-existent directory. + +=item * + +New %ENV entries now propagate to subprocesses. + +=item * + +$ENV{LIB} now used to search for libs under Visual C. + +=item * + +A failed (pseudo)fork now returns undef and sets errno to EAGAIN. + +=item * + +Allow REG_EXPAND_SZ keys in the registry. + +=item * + +Can now send() from all threads, not just the first one. + +=item * + +Fake signal handling reenabled, bugs and all. + +=item * + +Less stack reserved per thread so that more threads can run +concurrently. (Still 16M per thread.) + +=item * + +Ctmpdir()> now prefers C:/temp over /tmp +(works better when perl is running as service). + +=item * + +Better UNC path handling under ithreads. + +=item * + +wait() and waitpid() now work much better. + +=item * + +winsock handle leak fixed. + +=back + +=back + +=head1 New or Changed Diagnostics + +All regular expression compilation error messages are now hopefully +easier to understand both because the error message now comes before +the failed regex and because the point of failure is now clearly +marked. + +The various "opened only for", "on closed", "never opened" warnings +drop the C prefix for filehandles in the C
package, +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. + +=head1 Changed Internals + +=over 4 + +=item * + +perlapi.pod (a companion to perlguts) now attempts to document the +internal API. + +=item * + +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. + +=item * + +Added rsignal(), whichsig(), do_join() to the publicised API. + +=item * + +Made possible to propagate customised exceptions via croak()ing. + +=item * + +Added is_utf8_char(), is_utf8_string(), bytes_to_utf8(), and utf8_to_bytes(). + +=item * + +Now xsubs can have attributes just like subs. + +=back =head1 Known Problems -=head1 Obsolete Diagnostics +=head2 Unicode Support Still Far From Perfect + +We're working on it. Stay tuned. + +=head2 EBCDIC Still A Lost Platform + +The plan is to bring them back. + +=head2 Building Extensions Can Fail Because Of Largefiles + +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. + +=head2 ftmp-security tests warn 'system possibly insecure' + +Don't panic. Read INSTALL 'make test' section instead. + +=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 Long Doubles Still Don't Work In Solaris + +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.) + +=head2 Linux With Sfio Fails op/misc Test 48 + +No known fix. + +=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 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 Storable tests fail in some platforms + +If any Storable tests fail the use of Storable is not advisable. + +=over 4 + +=item * + +Many Storable tests fail on AIX configured with 64 bit integers. + +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. + +=item * + +DOS DJGPP may hang when testing Storable. + +=item * + +st-06compat fails in UNICOS and UNICOS/mk. + +This means that you cannot read old (pre-Storable-0.7) Storable images +made in other platforms. + +=item * + +st-store.t and st-retrieve may fail with Compaq C 6.2 on OpenVMS Alpha 7.2. + +=back + +=head2 Threads Are Still Experimental + +Multithreading is still an experimental feature. Some platforms +emit the following message for lib/thr5005 + + # + # 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. ;-) + # + +and another known thread-related 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 + +=head2 The Compiler Suite Is Still Experimental + +The compiler suite is slowly getting better but is nowhere near +working order yet. The backend part that has seen perhaps the most +progress is the bytecode compiler. =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. -There may also be information at http://www.perl.com/perl/, the Perl -Home Page. +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. If you believe you have an unreported bug, please run the B program included with your release. Be sure to trim your bug down to a tiny but sufficient test case. Your bug report, along with the -output of C, will be sent off to perlbug@perl.com to be +output of C, will be sent off to perlbug@perl.org to be analysed by the Perl porting team. =head1 SEE ALSO @@ -112,9 +935,9 @@ The F and F files for copyright information. =head1 HISTORY -Written by Gurusamy Sarathy >, with many -contributions from The Perl Porters. +Written by Jarkko Hietaniemi >, with many contributions +from The Perl Porters and Perl Users submitting feedback and patches. -Send omissions or corrections to >. +Send omissions or corrections to >. =cut