1PERL572DELTA(1) Perl Programmers Reference Guide PERL572DELTA(1)
2
6 perl572delta - what's new for perl v5.7.2
7
9 This document describes differences between the 5.7.1 release and the
10 5.7.2 release.
11 (To view the differences between the 5.6.0 release and the 5.7.0
13 release, see perl570delta. To view the differences between the 5.7.0
14 release and the 5.7.1 release, see perl571delta.)
15
17 (This change was already made in 5.7.0 but bears repeating here.)
18 A security vulnerability affecting all Perl versions prior to 5.6.1 was
20 found in August 2000. The vulnerability does not affect default
21 installations and as far as is known affects only the Linux platform.
22 You should upgrade your Perl to 5.6.1 as soon as possible. Patches for
24 earlier releases exist but using the patches require full recompilation
25 from the source code anyway, so 5.6.1 is your best choice.
26 See http://www.cpan.org/src/5.0/sperl-2000-08-05/sperl-2000-08-05.txt
28 for more information.
29
31 64-bit platforms and malloc
32 If your pointers are 64 bits wide, the Perl malloc is no more being
34 used because it simply does not work with 8-byte pointers. Also, usu‐
35 ally the system malloc on such platforms are much better optimized for
36 such large memory models than the Perl malloc.
37 AIX Dynaloading
39 The AIX dynaloading now uses in AIX releases 4.3 and newer the native
41 dlopen interface of AIX instead of the old emulated interface. This
42 change will probably break backward compatibility with compiled mod‐
43 ules. The change was made to make Perl more compliant with other
44 applications like modperl which are using the AIX native interface.
45 Socket Extension Dynamic in VMS
47 The Socket extension is now dynamically loaded instead of being stati‐
49 cally built in. This may or may not be a problem with ancient TCP/IP
50 stacks of VMS: we do not know since we weren't able to test Perl in
51 such configurations.
52 Different Definition of the Unicode Character Classes \p{In...}
54 As suggested by the Unicode consortium, the Unicode character classes
56 now prefer scripts as opposed to blocks (as defined by Unicode); in
57 Perl, when the "\p{In....}" and the "\p{In....}" regular expression
58 constructs are used. This has changed the definition of some of those
59 character classes.
60 The difference between scripts and blocks is that scripts are the
62 glyphs used by a language or a group of languages, while the blocks are
63 more artificial groupings of 256 characters based on the Unicode num‐
64 bering.
65 In general this change results in more inclusive Unicode character
67 classes, but changes to the other direction also do take place: for
68 example while the script "Latin" includes all the Latin characters and
69 their various diacritic-adorned versions, it does not include the vari‐
70 ous punctuation or digits (since they are not solely "Latin").
71 Changes in the character class semantics may have happened if a script
73 and a block happen to have the same name, for example "Hebrew". In
74 such cases the script wins and "\p{InHebrew}" now means the script def‐
75 inition of Hebrew. The block definition in still available, though, by
76 appending "Block" to the name: "\p{InHebrewBlock}" means what
77 "\p{InHebrew}" meant in perl 5.6.0. For the full list of affected
78 character classes, see "Blocks" in perlunicode.
79 Deprecations
81 The current user-visible implementation of pseudo-hashes (the weird use
83 of the first array element) is deprecated starting from Perl 5.8.0 and
84 will be removed in Perl 5.10.0, and the feature will be implemented
85 differently. Not only is the current interface rather ugly, but the
86 current implementation slows down normal array and hash use quite
87 noticeably. The "fields" pragma interface will remain available.
88 The syntaxes "@a->[...]" and "@h->{...}" have now been deprecated.
90 The suidperl is also considered to be too much a risk to continue main‐
92 taining and the suidperl code is likely to be removed in a future
93 release.
94 The "package;" syntax ("package" without an argument has been depre‐
96 cated. Its semantics were never that clear and its implementation even
97 less so. If you have used that feature to disallow all but fully qual‐
98 ified variables, "use strict;" instead.
99 The chdir(undef) and chdir('') behaviors to match chdir() has been dep‐
101 recated. In future versions, chdir(undef) and chdir('') will simply
102 fail.
103
105 In general a lot of fixing has happened in the area of Perl's under‐
106 standing of numbers, both integer and floating point. Since in many
107 systems the standard number parsing functions like "strtoul()" and
108 "atof()" seem to have bugs, Perl tries to work around their deficien‐
109 cies. This results hopefully in more accurate numbers.
110 · The rules for allowing underscores (underbars) in numeric constants
112 have been relaxed and simplified: now you can have an underscore
113 between digits.
114 · GMAGIC (right-hand side magic) could in many cases such as string
116 concatenation be invoked too many times.
117 · Lexicals I: lexicals outside an eval "" weren't resolved correctly
119 inside a subroutine definition inside the eval "" if they were not
120 already referenced in the top level of the eval""ed code.
121 · Lexicals II: lexicals leaked at file scope into subroutines that
123 were declared before the lexicals.
124 · Lvalue subroutines can now return "undef" in list context.
126 · The "op_clear" and "op_null" are now exported.
128 · A new special regular expression variable has been introduced: $^N,
130 which contains the most-recently closed group (submatch).
131 · utime now supports "utime undef, undef, @files" to change the file
133 timestamps to the current time.
134 · The Perl parser has been stress tested using both random input and
136 Markov chain input.
137 · "eval "v200"" now works.
139 · VMS now works under PerlIO.
141 · END blocks are now run even if you exit/die in a BEGIN block. The
143 execution of END blocks is now controlled by PL_exit_flags &
144 PERL_EXIT_DESTRUCT_END. This enables the new behaviour for perl
145 embedders. This will default in 5.10. See perlembed.
146
148 New Modules and Distributions
149 · Attribute::Handlers - Simpler definition of attribute handlers
151 · ExtUtils::Constant - generate XS code to import C header constants
153 · I18N::Langinfo - query locale information
155 · I18N::LangTags - functions for dealing with RFC3066-style language
157 tags
158 · libnet - a collection of perl5 modules related to network program‐
160 ming
161 Perl installation leaves libnet unconfigured, use libnetcfg to con‐
163 figure.
164 · List::Util - selection of general-utility list subroutines
166 · Locale::Maketext - framework for localization
168 · Memoize - Make your functions faster by trading space for time
170 · NEXT - pseudo-class for method redispatch
172 · Scalar::Util - selection of general-utility scalar subroutines
174 · Test::More - yet another framework for writing test scripts
176 · Test::Simple - Basic utilities for writing tests
178 · Time::HiRes - high resolution ualarm, usleep, and gettimeofday
180 · Time::Piece - Object Oriented time objects
182 (Previously known as Time::Object.)
184 · Time::Seconds - a simple API to convert seconds to other date val‐
186 ues
187 · UnicodeCD - Unicode Character Database
189 Updated And Improved Modules and Pragmata
191 · B::Deparse module has been significantly enhanced. It now can
193 deparse almost all of the standard test suite (so that the tests
194 still succeed). There is a make target "test.deparse" for trying
195 this out.
196 · Class::Struct now assigns the array/hash element if the accessor is
198 called with an array/hash element as the sole argument.
199 · Cwd extension is now (even) faster.
201 · DB_File extension has been updated to version 1.77.
203 · Fcntl, Socket, and Sys::Syslog have been rewritten to use the new-
205 style constant dispatch section (see ExtUtils::Constant).
206 · File::Find is now (again) reentrant. It also has been made more
208 portable.
209 · File::Glob now supports "GLOB_LIMIT" constant to limit the size of
211 the returned list of filenames.
212 · IO::Socket::INET now supports "LocalPort" of zero (usually meaning
214 that the operating system will make one up.)
215 · The vars pragma now supports declaring fully qualified variables.
217 (Something that "our()" does not and will not support.)
218
220 · The emacs/e2ctags.pl is now much faster.
221 · h2ph now supports C trigraphs.
223 · h2xs uses the new ExtUtils::Constant module which will affect newly
225 created extensions that define constants. Since the new code is
226 more correct (if you have two constants where the first one is a
227 prefix of the second one, the first constant never gets defined),
228 less lossy (it uses integers for integer constant, as opposed to
229 the old code that used floating point numbers even for integer con‐
230 stants), and slightly faster, you might want to consider regenerat‐
231 ing your extension code (the new scheme makes regenerating easy).
232 h2xs now also supports C trigraphs.
233 · libnetcfg has been added to configure the libnet.
235 · The Pod::Html (and thusly pod2html) now allows specifying a cache
237 directory.
238
240 · Locale::Maketext::TPJ13 is an article about software localization,
241 originally published in The Perl Journal #13, republished here with
242 kind permission.
243 · More README.$PLATFORM files have been converted into pod, which
245 also means that they also be installed as perl$PLATFORM documenta‐
246 tion files. The new files are perlapollo, perlbeos, perldgux,
247 perlhurd, perlmint, perlnetware, perlplan9, perlqnx, and perltru64.
248 · The Todo and Todo-5.6 files have been merged into perltodo.
250 · Use of the gprof tool to profile Perl has been documented in perl‐
252 hack. There is a make target "perl.gprof" for generating a gpro‐
253 filed Perl executable.
254
256 New Or Improved Platforms
257 · AIX should now work better with gcc, threads, and 64-bitness. Also
259 the long doubles support in AIX should be better now. See perlaix.
260 · AtheOS ( http://www.atheos.cx/ ) is a new platform.
262 · DG/UX platform now supports the 5.005-style threads. See perldgux.
264 · DYNIX/ptx platform (a.k.a. dynixptx) is supported at or near osvers
266 4.5.2.
267 · Several Mac OS (Classic) portability patches have been applied. We
269 hope to get a fully working port by 5.8.0. (The remaining problems
270 relate to the changed IO model of Perl.) See perlmacos.
271 · Mac OS X (or Darwin) should now be able to build Perl even on HFS+
273 filesystems. (The case-insensitivity confused the Perl build
274 process.)
275 · NetWare from Novell is now supported. See perlnetware.
277 · The Amdahl UTS UNIX mainframe platform is now supported.
279 Generic Improvements
281 · In AFS installations one can configure the root of the AFS to be
283 somewhere else than the default /afs by using the Configure parame‐
284 ter "-Dafsroot=/some/where/else".
285 · The version of Berkeley DB used when the Perl (and, presumably, the
287 DB_File extension) was built is now available as @Config{qw(db_ver‐
288 sion_major db_version_minor db_version_patch)} from Perl and as
289 "DB_VERSION_MAJOR_CFG DB_VERSION_MINOR_CFG DB_VERSION_PATCH_CFG"
290 from C.
291 · The Thread extension is now not built at all under ithreads ("Con‐
293 figure -Duseithreads") because it wouldn't work anyway (the Thread
294 extension requires being Configured with "-Duse5005threads").
295 · The "B::Deparse" compiler backend has been so significantly
297 improved that almost the whole Perl test suite passes after being
298 deparsed. A make target has been added to help in further testing:
299 "make test.deparse".
300
302 · The autouse pragma didn't work for Multi::Part::Function::Names.
303 · The behaviour of non-decimal but numeric string constants such as
305 "0x23" was platform-dependent: in some platforms that was seen as
306 35, in some as 0, in some as a floating point number (don't ask).
307 This was caused by Perl using the operating system libraries in a
308 situation where the result of the string to number conversion is
309 undefined: now Perl consistently handles such strings as zero in
310 numeric contexts.
311 · dprofpp -R didn't work.
313 · PERL5OPT with embedded spaces didn't work.
315 · Sys::Syslog ignored the "LOG_AUTH" constant.
317 Platform Specific Changes and Fixes
319 · Some versions of glibc have a broken modfl(). This affects builds
321 with "-Duselongdouble". This version of Perl detects this broken‐
322 ness and has a workaround for it. The glibc release 2.2.2 is known
323 to have fixed the modfl() bug.
324
326 · In the regular expression diagnostics the "<< HERE" marker intro‐
327 duced in 5.7.0 has been changed to be "<-- HERE" since too many
328 people found the "<<" to be too similar to here-document starters.
329 · If you try to "pack" in perlfunc a number less than 0 or larger
331 than 255 using the "C" format you will get an optional warning.
332 Similarly for the "c" format and a number less than -128 or more
333 than 127.
334 · Certain regex modifiers such as "(?o)" make sense only if applied
336 to the entire regex. You will an optional warning if you try to do
337 otherwise.
338 · Using arrays or hashes as references (e.g. "%foo->{bar}" has been
340 deprecated for a while. Now you will get an optional warning.
341
343 MAGIC constants
344 The MAGIC constants (e.g. 'P') have been macrofied (e.g.
346 "PERL_MAGIC_TIED") for better source code readability and maintainabil‐
347 ity.
348 Better commented code
350 perly.c, sv.c, and sv.h have now been extensively commented.
352 Regex pre-/post-compilation items matched up
354 The regex compiler now maintains a structure that identifies nodes in
356 the compiled bytecode with the corresponding syntactic features of the
357 original regex expression. The information is attached to the new
358 "offsets" member of the "struct regexp". See perldebguts for more com‐
359 plete information.
360 gcc -Wall
362 The C code has been made much more "gcc -Wall" clean. Some warning
364 messages still remain, though, so if you are compiling with gcc you
365 will see some warnings about dubious practices. The warnings are being
366 worked on.
367
369 Several new tests have been added, especially for the lib subsection.
370 The tests are now reported in a different order than in earlier Perls.
372 (This happens because the test scripts from under t/lib have been moved
373 to be closer to the library/extension they are testing.)
374
376 Note that unlike other sections in this document (which describe
377 changes since 5.7.0) this section is cumulative containing known prob‐
378 lems for all the 5.7 releases.
379 AIX
381 · In AIX 4.2 Perl extensions that use C++ functions that use statics
383 may have problems in that the statics are not getting initialized.
384 In newer AIX releases this has been solved by linking Perl with the
385 libC_r library, but unfortunately in AIX 4.2 the said library has
386 an obscure bug where the various functions related to time (such as
387 time() and gettimeofday()) return broken values, and therefore in
388 AIX 4.2 Perl is not linked against the libC_r.
389 · vac 5.0.0.0 May Produce Buggy Code For Perl
391 The AIX C compiler vac version 5.0.0.0 may produce buggy code,
393 resulting in few random tests failing, but when the failing tests
394 are run by hand, they succeed. We suggest upgrading to at least
395 vac version 5.0.1.0, that has been known to compile Perl correctly.
396 "lslpp -L⎪grep vac.C" will tell you the vac version.
397 Amiga Perl Invoking Mystery
399 One cannot call Perl using the "volume:" syntax, that is, "perl -v"
401 works, but for example "bin:perl -v" doesn't. The exact reason is
402 known but the current suspect is the ixemul library.
403 lib/ftmp-security tests warn 'system possibly insecure'
405 Don't panic. Read INSTALL 'make test' section instead.
407 Cygwin intermittent failures of lib/Memoize/t/expire_file 11 and 12
409 The subtests 11 and 12 sometimes fail and sometimes work.
411 HP-UX lib/io_multihomed Fails When LP64-Configured
413 The lib/io_multihomed test may hang in HP-UX if Perl has been config‐
415 ured to be 64-bit. Because other 64-bit platforms do not hang in this
416 test, HP-UX is suspect. All other tests pass in 64-bit HP-UX. The test
417 attempts to create and connect to "multihomed" sockets (sockets which
418 have multiple IP addresses).
419 HP-UX lib/posix Subtest 9 Fails When LP64-Configured
421 If perl is configured with -Duse64bitall, the successful result of the
423 subtest 10 of lib/posix may arrive before the successful result of the
424 subtest 9, which confuses the test harness so much that it thinks the
425 subtest 9 failed.
426 Linux With Sfio Fails op/misc Test 48
428 No known fix.
430 OS/390
432 OS/390 has rather many test failures but the situation is actually bet‐
434 ter than it was in 5.6.0, it's just that so many new modules and tests
435 have been added.
436 Failed Test Stat Wstat Total Fail Failed List of Failed
438 -----------------------------------------------------------------------------
439 ../ext/B/Deparse.t 14 1 7.14% 14
440 ../ext/B/Showlex.t 1 1 100.00% 1
441 ../ext/Encode/Encode/Tcl.t 610 13 2.13% 592 594 596 598
442 600 602 604-610
443 ../ext/IO/lib/IO/t/io_unix.t 113 28928 5 3 60.00% 3-5
444 ../ext/POSIX/POSIX.t 29 1 3.45% 14
445 ../ext/Storable/t/lock.t 255 65280 5 3 60.00% 3-5
446 ../lib/locale.t 129 33024 117 19 16.24% 99-117
447 ../lib/warnings.t 434 1 0.23% 75
448 ../lib/ExtUtils.t 27 1 3.70% 25
449 ../lib/Math/BigInt/t/bigintpm.t 1190 1 0.08% 1145
450 ../lib/Unicode/UCD.t 81 48 59.26% 1-16 49-64 66-81
451 ../lib/User/pwent.t 9 1 11.11% 4
452 op/pat.t 660 6 0.91% 242-243 424-425
453 626-627
454 op/split.t 0 9 ?? ?? % ??
455 op/taint.t 174 3 1.72% 156 162 168
456 op/tr.t 70 3 4.29% 50 58-59
457 Failed 16/422 test scripts, 96.21% okay. 105/23251 subtests failed, 99.55% okay.
458 op/sprintf tests 129 and 130
460 The op/sprintf tests 129 and 130 are known to fail on some platforms.
462 Examples include any platform using sfio, and Compaq/Tandem's Non‐
463 Stop-UX. The failing platforms do not comply with the ANSI C Standard,
464 line 19ff on page 134 of ANSI X3.159 1989 to be exact. (They produce
465 something other than "1" and "-1" when formatting 0.6 and -0.6 using
466 the printf format "%.0f", most often they produce "0" and "-0".)
467 Failure of Thread tests
469 Note that support for 5.005-style threading remains experimental.
471 The following tests are known to fail due to fundamental problems in
473 the 5.005 threading implementation. These are not new failures--Perl
474 5.005_0x has the same bugs, but didn't have these tests.
475 lib/autouse.t 4
477 t/lib/thr5005.t 19-20
478 UNICOS
480 · ext/POSIX/sigaction subtests 6 and 13 may fail.
482 · lib/ExtUtils may spuriously claim that subtest 28 failed, which is
484 interesting since the test only has 27 tests.
485 · Numerous numerical test failures
487 op/numconvert 209,210,217,218
489 op/override 7
490 ext/Time/HiRes/HiRes 9
491 lib/Math/BigInt/t/bigintpm 1145
492 lib/Math/Trig 25
493 These tests fail because of yet unresolved floating point inaccura‐
495 cies.
496 UTS
498 There are a few known test failures, see perluts.
500 VMS
502 Rather many tests are failing in VMS but that actually more tests suc‐
504 ceed in VMS than they used to, it's just that there are many, many more
505 tests than there used to be.
506 Here are the known failures from some compiler/platform combinations.
508 DEC C V5.3-006 on OpenVMS VAX V6.2
510 [-.ext.list.util.t]tainted..............FAILED on test 3
512 [-.ext.posix]sigaction..................FAILED on test 7
513 [-.ext.time.hires]hires.................FAILED on test 14
514 [-.lib.file.find]taint..................FAILED on test 17
515 [-.lib.math.bigint.t]bigintpm...........FAILED on test 1183
516 [-.lib.test.simple.t]exit...............FAILED on test 1
517 [.lib]vmsish............................FAILED on test 13
518 [.op]sprintf............................FAILED on test 12
519 Failed 8/399 tests, 91.23% okay.
520 DEC C V6.0-001 on OpenVMS Alpha V7.2-1 and Compaq C V6.2-008 on OpenVMS
522 Alpha V7.1
523 [-.ext.list.util.t]tainted..............FAILED on test 3
525 [-.lib.file.find]taint..................FAILED on test 17
526 [-.lib.test.simple.t]exit...............FAILED on test 1
527 [.lib]vmsish............................FAILED on test 13
528 Failed 4/399 tests, 92.48% okay.
529 Compaq C V6.4-005 on OpenVMS Alpha 7.2.1
531 [-.ext.b]showlex........................FAILED on test 1
533 [-.ext.list.util.t]tainted..............FAILED on test 3
534 [-.lib.file.find]taint..................FAILED on test 17
535 [-.lib.test.simple.t]exit...............FAILED on test 1
536 [.lib]vmsish............................FAILED on test 13
537 [.op]misc...............................FAILED on test 49
538 Failed 6/401 tests, 92.77% okay.
539 Win32
541 In multi-CPU boxes there are some problems with the I/O buffering: some
543 output may appear twice.
544 Localising a Tied Variable Leaks Memory
546 use Tie::Hash;
548 tie my %tie_hash => 'Tie::StdHash';
549 ...
551 local($tie_hash{Foo}) = 1; # leaks
553 Code like the above is known to leak memory every time the local() is
555 executed.
556 Self-tying of Arrays and Hashes Is Forbidden
558 Self-tying of arrays and hashes is broken in rather deep and hard-to-
560 fix ways. As a stop-gap measure to avoid people from getting frus‐
561 trated at the mysterious results (core dumps, most often) it is for now
562 forbidden (you will get a fatal error even from an attempt).
563 Variable Attributes are not Currently Usable for Tieing
565 This limitation will hopefully be fixed in future. (Subroutine
567 attributes work fine for tieing, see Attribute::Handlers).
568 Building Extensions Can Fail Because Of Largefiles
570 Some extensions like mod_perl are known to have issues with `large‐
572 files', a change brought by Perl 5.6.0 in which file offsets default to
573 64 bits wide, where supported. Modules may fail to compile at all or
574 compile and work incorrectly. Currently there is no good solution for
575 the problem, but Configure now provides appropriate non-largefile
576 ccflags, ldflags, libswanted, and libs in the %Config hash (e.g., $Con‐
577 fig{ccflags_nolargefiles}) so the extensions that are having problems
578 can try configuring themselves without the largefileness. This is
579 admittedly not a clean solution, and the solution may not even work at
580 all. One potential failure is whether one can (or, if one can, whether
581 it's a good idea) link together at all binaries with different ideas
582 about file offsets, all this is platform-dependent.
583 The Compiler Suite Is Still Experimental
585 The compiler suite is slowly getting better but is nowhere near working
587 order yet.
588 The Long Double Support is Still Experimental
590 The ability to configure Perl's numbers to use "long doubles", floating
592 point numbers of hopefully better accuracy, is still experimental. The
593 implementations of long doubles are not yet widespread and the existing
594 implementations are not quite mature or standardised, therefore trying
595 to support them is a rare and moving target. The gain of more preci‐
596 sion may also be offset by slowdown in computations (more bits to move
597 around, and the operations are more likely to be executed by less opti‐
598 mised libraries).
599
601 If you find what you think is a bug, you might check the articles
602 recently posted to the comp.lang.perl.misc newsgroup and the perl bug
603 database at http://bugs.perl.org/ There may also be information at
604 http://www.perl.com/perl/ , the Perl Home Page.
605 If you believe you have an unreported bug, please run the perlbug pro‐
607 gram included with your release. Be sure to trim your bug down to a
608 tiny but sufficient test case. Your bug report, along with the output
609 of "perl -V", will be sent off to perlbug@perl.org to be analysed by
610 the Perl porting team.
611
613 The Changes file for exhaustive details on what changed.
614 The INSTALL file for how to build Perl.
616 The README file for general stuff.
618 The Artistic and Copying files for copyright information.
620
622 Written by Jarkko Hietaniemi <jhi@iki.fi>, with many contributions from
623 The Perl Porters and Perl Users submitting feedback and patches.
624 Send omissions or corrections to <perlbug@perl.org>.
626perl v5.8.8 2006-01-07 PERL572DELTA(1)