=head1 NAME perl571delta - what's new for perl v5.7.2 =head1 DESCRIPTION This document describes differences between the 5.7.1 release and the 5.7.2 release. (To view the differences between the 5.6.0 release and the 5.7.0 release, see L. To view the differences between the 5.7.0 release and the 5.7.1 release, see L.) =head1 Security Vulnerability Closed (This change was already made in 5.7.0 but bears repeating here.) A security vulnerability affecting all Perl versions prior to 5.6.1 was found in August 2000. The vulnerability does not affect default installations and as far as is known affects only the Linux platform. You should upgrade your Perl to 5.6.1 as soon as possible. Patches for earlier releases exist but using the patches require full recompilation from the source code anyway, so 5.6.1 is your best choice. See http://www.cpan.org/src/5.0/sperl-2000-08-05/sperl-2000-08-05.txt for more information. =head1 Incompatible Changes =head2 64-bit platforms and malloc If your pointers are 64 bits wide, the Perl malloc is no more being used because it simply does not work with 8-byte pointers. Also, 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 the native dlopen interface of AIX, (given the AIX is recent enough) instead of the old emulated interface. This will probably break backward compatibility with compiled modules. =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 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 'fields' 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. =head1 Core Enhancements 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 * The rules for allowing underscores (underbars) in numeric constants have been relaxed and simplified: now you can have an underscore B. =item * GMAGIC (right-hand side magic) could in many cases such as concatenation of string be invoked too many times. =item * Lexicals I: lexicals outside an eval "" weren't resolved correctly inside a subroutine definition inside the eval "" if they were not already referenced in the top level of the eval""ed code. =item * Lexicals II: lexicals leaked at file scope into subroutines that were declared before the lexicals. =item * Lvalue subroutines can now return C in list context. =item * The MAGIC constants (e.g. C<'P'>) have been macrofied (e.g. C) for better source code readability and maintainability. =item * The C and C are now exported. =item * L now supports C to change the file timestamps to the current time. =item * The Perl parser has been stress tested using both random input and Markov chain input. =item * C now works. =item * VMS now works under PerlIO. =back =head1 Modules and Pragmata =head2 New Modules and Distribution =over 4 =item * L - Simpler definition of attribute handlers =item * L - generate XS code to import C header constants =item * L - functions for dealing with RFC3066-style language tags =item * L - a collection of perl5 modules related to network programming Perl installation leaves libnet unconfigured, use F to configure. =item * L - selection of general-utility list subroutines =item * L - framework for localization =item * L - Make your functions faster by trading space for time =item * L - pseudo-class for method redispatch =item * L - selection of general-utility scalar subroutines =item * L - yet another framework for writing test scripts =item * L - Basic utilities for writing tests =item * L - high resolution ualarm, usleep, and gettimeofday =item * L - Object Oriented time objects (Previously known as L.) =back =head2 Updated And Improved Modules and Pragmata =over 4 =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 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). =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 * 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. =item * (Code documentation) F and F have now been extensively commented. =back =head1 Installation and Configuration Improvements =head2 New Or Improved Platforms =over 4 =item * AIX should now work better with gcc. Also longdouble 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 * 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 =head2 Generic Improvements =over 4 =item * 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. =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 =head1 Selected Bug Fixes =over 5 =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 * 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. =back =head1 New or Changed Diagnostics =over 4 =item * 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 Changed Internals =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. =head1 New Tests Several new tests have been added, especially for the F subsection. 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.) =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 * If Perl is configured to use long doubles the op/int subtests 13 and 14 and the ext/POSIX subtest 14 may fail. =item * If Perl is configured to use threads the op/magic subtest 28 may fail. =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-Configur 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 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 else than "1" and "-1" when formatting 0.6 and -0.6 using the printf format "%.0f", most often they produce "0" and "-0".) =head2 Failure of Thread tests 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 * ext/POSIX/sigaction subtests 6 and 13 may fail. =item * lib/ExtUtils may spuriously claim that subtest 28 failed, which is interesting since the test only has 27 tests. =item * 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 UNICOS/mk ext/IPC/SysV/t/sem test 8 No known fix. =head2 UTS Many floating point inaccuracies: op/numconvert 511,657,658,659,665-667,831,991,1151 op/pack 10,22,149,156 op/sprintf 8,10,13,102-107,134-135,146-153,159-162 lib/Math/BigInt/bigintpm 1145,1183 lib/Math/Complex 250,257,514,521,722-724, 934,935,945,949,955,956,975,976 ext/POSIX/POSIX 14 =head2 VMS DEC C V5.3-006 on OpenVMS VAX V6.2 [-.ext.list.util.t]tainted..............FAILED on test 3 [-.ext.posix]sigaction..................FAILED on test 7 [-.ext.time.hires]hires.................FAILED on test 14 [-.lib.file.find]taint..................FAILED on test 17 [-.lib.math.bigint.t]bigintpm...........FAILED on test 1183 [-.lib.test.simple.t]exit...............FAILED on test 1 [.lib]vmsish............................FAILED on test 13 [.op]sprintf............................FAILED on test 12 Failed 8/399 tests, 91.23% okay. DEC C V6.0-001 on OpenVMS Alpha V7.2-1 [-.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. =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 working order yet. =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 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.org to be analysed by the Perl porting team. =head1 SEE ALSO The F file for exhaustive details on what changed. The F file for how to build Perl. The F file for general stuff. 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 >. =cut