1PERLDELTA(1) Perl Programmers Reference Guide PERLDELTA(1)
2
6 perldelta - what is new for perl v5.10.1
7
9 This document describes differences between the 5.10.0 release and the
10 5.10.1 release.
11 If you are upgrading from an earlier release such as 5.8.8, first read
13 the perl5100delta, which describes differences between 5.8.8 and 5.10.0
14
16 Switch statement changes
17 The handling of complex expressions by the "given"/"when" switch
18 statement has been enhanced. There are two new cases where "when" now
19 interprets its argument as a boolean, instead of an expression to be
20 used in a smart match:
21 flip-flop operators
23 The ".." and "..." flip-flop operators are now evaluated in boolean
24 context, following their usual semantics; see "Range Operators" in
25 perlop.
26 Note that, as in perl 5.10.0, "when (1..10)" will not work to test
28 whether a given value is an integer between 1 and 10; you should
29 use "when ([1..10])" instead (note the array reference).
30 However, contrary to 5.10.0, evaluating the flip-flop operators in
32 boolean context ensures it can now be useful in a "when()", notably
33 for implementing bistable conditions, like in:
34 when (/^=begin/ .. /^=end/) {
36 # do something
37 }
38 defined-or operator
40 A compound expression involving the defined-or operator, as in
41 "when (expr1 // expr2)", will be treated as boolean if the first
42 expression is boolean. (This just extends the existing rule that
43 applies to the regular or operator, as in "when (expr1 || expr2)".)
44 The next section details more changes brought to the semantics to the
46 smart match operator, that naturally also modify the behaviour of the
47 switch statements where smart matching is implicitly used.
48 Smart match changes
50 Changes to type-based dispatch
51 The smart match operator "~~" is no longer commutative. The behaviour
53 of a smart match now depends primarily on the type of its right hand
54 argument. Moreover, its semantics have been adjusted for greater
55 consistency or usefulness in several cases. While the general backwards
56 compatibility is maintained, several changes must be noted:
57 · Code references with an empty prototype are no longer treated
59 specially. They are passed an argument like the other code
60 references (even if they choose to ignore it).
61 · "%hash ~~ sub {}" and "@array ~~ sub {}" now test that the
63 subroutine returns a true value for each key of the hash (or
64 element of the array), instead of passing the whole hash or array
65 as a reference to the subroutine.
66 · Due to the commutativity breakage, code references are no longer
68 treated specially when appearing on the left of the "~~" operator,
69 but like any vulgar scalar.
70 · "undef ~~ %hash" is always false (since "undef" can't be a key in a
72 hash). No implicit conversion to "" is done (as was the case in
73 perl 5.10.0).
74 · "$scalar ~~ @array" now always distributes the smart match across
76 the elements of the array. It's true if one element in @array
77 verifies "$scalar ~~ $element". This is a generalization of the old
78 behaviour that tested whether the array contained the scalar.
79 The full dispatch table for the smart match operator is given in "Smart
81 matching in detail" in perlsyn.
82 Smart match and overloading
84 According to the rule of dispatch based on the rightmost argument type,
86 when an object overloading "~~" appears on the right side of the
87 operator, the overload routine will always be called (with a 3rd
88 argument set to a true value, see overload.) However, when the object
89 will appear on the left, the overload routine will be called only when
90 the rightmost argument is a simple scalar. This way distributivity of
91 smart match across arrays is not broken, as well as the other
92 behaviours with complex types (coderefs, hashes, regexes). Thus,
93 writers of overloading routines for smart match mostly need to worry
94 only with comparing against a scalar, and possibly with stringification
95 overloading; the other common cases will be automatically handled
96 consistently.
97 "~~" will now refuse to work on objects that do not overload it (in
99 order to avoid relying on the object's underlying structure). (However,
100 if the object overloads the stringification or the numification
101 operators, and if overload fallback is active, it will be used instead,
102 as usual.)
103 Other incompatible changes
105 · The semantics of "use feature :5.10*" have changed slightly. See
106 "Modules and Pragmata" for more information.
107 · It is now a run-time error to use the smart match operator "~~"
109 with an object that has no overload defined for it. (This way "~~"
110 will not break encapsulation by matching against the object's
111 internal representation as a reference.)
112 · The version control system used for the development of the perl
114 interpreter has been switched from Perforce to git. This is mainly
115 an internal issue that only affects people actively working on the
116 perl core; but it may have minor external visibility, for example
117 in some of details of the output of "perl -V". See perlrepository
118 for more information.
119 · The internal structure of the "ext/" directory in the perl source
121 has been reorganised. In general, a module "Foo::Bar" whose source
122 was stored under ext/Foo/Bar/ is now located under ext/Foo-Bar/.
123 Also, some modules have been moved from lib/ to ext/. This is
124 purely a source tarball change, and should make no difference to
125 the compilation or installation of perl, unless you have a very
126 customised build process that explicitly relies on this structure,
127 or which hard-codes the "nonxs_ext" Configure parameter.
128 Specifically, this change does not by default alter the location of
129 any files in the final installation.
130 · As part of the "Test::Harness" 2.x to 3.x upgrade, the experimental
132 "Test::Harness::Straps" module has been removed. See "Updated
133 Modules" for more details.
134 · As part of the "ExtUtils::MakeMaker" upgrade, the
136 "ExtUtils::MakeMaker::bytes" and "ExtUtils::MakeMaker::vmsish"
137 modules have been removed from this distribution.
138 · "Module::CoreList" no longer contains the %:patchlevel hash.
140 · This one is actually a change introduced in 5.10.0, but it was
142 missed from that release's perldelta, so it is mentioned here
143 instead.
144 A bugfix related to the handling of the "/m" modifier and "qr"
146 resulted in a change of behaviour between 5.8.x and 5.10.0:
147 # matches in 5.8.x, doesn't match in 5.10.0
149 $re = qr/^bar/; "foo\nbar" =~ /$re/m;
150
152 Unicode Character Database 5.1.0
153 The copy of the Unicode Character Database included in Perl 5.10.1 has
154 been updated to 5.1.0 from 5.0.0. See
155 <http://www.unicode.org/versions/Unicode5.1.0/#NotableChanges> for the
156 notable changes.
157 A proper interface for pluggable Method Resolution Orders
159 As of Perl 5.10.1 there is a new interface for plugging and using
160 method resolution orders other than the default (linear depth first
161 search). The C3 method resolution order added in 5.10.0 has been re-
162 implemented as a plugin, without changing its Perl-space interface. See
163 perlmroapi for more information.
164 The "overloading" pragma
166 This pragma allows you to lexically disable or enable overloading for
167 some or all operations. (Yuval Kogman)
168 Parallel tests
170 The core distribution can now run its regression tests in parallel on
171 Unix-like platforms. Instead of running "make test", set "TEST_JOBS" in
172 your environment to the number of tests to run in parallel, and run
173 "make test_harness". On a Bourne-like shell, this can be done as
174 TEST_JOBS=3 make test_harness # Run 3 tests in parallel
176 An environment variable is used, rather than parallel make itself,
178 because TAP::Harness needs to be able to schedule individual non-
179 conflicting test scripts itself, and there is no standard interface to
180 "make" utilities to interact with their job schedulers.
181 Note that currently some test scripts may fail when run in parallel
183 (most notably "ext/IO/t/io_dir.t"). If necessary run just the failing
184 scripts again sequentially and see if the failures go away.
185 DTrace support
187 Some support for DTrace has been added. See "DTrace support" in
188 INSTALL.
189 Support for "configure_requires" in CPAN module metadata
191 Both "CPAN" and "CPANPLUS" now support the "configure_requires" keyword
192 in the "META.yml" metadata file included in most recent CPAN
193 distributions. This allows distribution authors to specify
194 configuration prerequisites that must be installed before running
195 Makefile.PL or Build.PL.
196 See the documentation for "ExtUtils::MakeMaker" or "Module::Build" for
198 more on how to specify "configure_requires" when creating a
199 distribution for CPAN.
200
202 New Modules and Pragmata
203 "autodie"
204 This is a new lexically-scoped alternative for the "Fatal" module.
205 The bundled version is 2.06_01. Note that in this release, using a
206 string eval when "autodie" is in effect can cause the autodie
207 behaviour to leak into the surrounding scope. See "BUGS" in autodie
208 for more details.
209 "Compress::Raw::Bzip2"
211 This has been added to the core (version 2.020).
212 "parent"
214 This pragma establishes an ISA relationship with base classes at
215 compile time. It provides the key feature of "base" without the
216 feature creep.
217 "Parse::CPAN::Meta"
219 This has been added to the core (version 1.39).
220 Pragmata Changes
222 "attributes"
223 Upgraded from version 0.08 to 0.09.
224 "attrs"
226 Upgraded from version 1.02 to 1.03.
227 "base"
229 Upgraded from version 2.13 to 2.14. See parent for a replacement.
230 "bigint"
232 Upgraded from version 0.22 to 0.23.
233 "bignum"
235 Upgraded from version 0.22 to 0.23.
236 "bigrat"
238 Upgraded from version 0.22 to 0.23.
239 "charnames"
241 Upgraded from version 1.06 to 1.07.
242 The Unicode NameAliases.txt database file has been added. This has
244 the effect of adding some extra "\N" character names that formerly
245 wouldn't have been recognised; for example, "\N{LATIN CAPITAL
246 LETTER GHA}".
247 "constant"
249 Upgraded from version 1.13 to 1.17.
250 "feature"
252 The meaning of the ":5.10" and ":5.10.X" feature bundles has
253 changed slightly. The last component, if any (i.e. "X") is simply
254 ignored. This is predicated on the assumption that new features
255 will not, in general, be added to maintenance releases. So ":5.10"
256 and ":5.10.X" have identical effect. This is a change to the
257 behaviour documented for 5.10.0.
258 "fields"
260 Upgraded from version 2.13 to 2.14 (this was just a version bump;
261 there were no functional changes).
262 "lib"
264 Upgraded from version 0.5565 to 0.62.
265 "open"
267 Upgraded from version 1.06 to 1.07.
268 "overload"
270 Upgraded from version 1.06 to 1.07.
271 "overloading"
273 See "The "overloading" pragma" above.
274 "version"
276 Upgraded from version 0.74 to 0.77.
277 Updated Modules
279 "Archive::Extract"
280 Upgraded from version 0.24 to 0.34.
281 "Archive::Tar"
283 Upgraded from version 1.38 to 1.52.
284 "Attribute::Handlers"
286 Upgraded from version 0.79 to 0.85.
287 "AutoLoader"
289 Upgraded from version 5.63 to 5.68.
290 "AutoSplit"
292 Upgraded from version 1.05 to 1.06.
293 "B" Upgraded from version 1.17 to 1.22.
295 "B::Debug"
297 Upgraded from version 1.05 to 1.11.
298 "B::Deparse"
300 Upgraded from version 0.83 to 0.89.
301 "B::Lint"
303 Upgraded from version 1.09 to 1.11.
304 "B::Xref"
306 Upgraded from version 1.01 to 1.02.
307 "Benchmark"
309 Upgraded from version 1.10 to 1.11.
310 "Carp"
312 Upgraded from version 1.08 to 1.11.
313 "CGI"
315 Upgraded from version 3.29 to 3.43. (also includes the
316 "default_value for popup_menu()" fix from 3.45).
317 "Compress::Zlib"
319 Upgraded from version 2.008 to 2.020.
320 "CPAN"
322 Upgraded from version 1.9205 to 1.9402. "CPAN::FTP" has a local fix
323 to stop it being too verbose on download failure.
324 "CPANPLUS"
326 Upgraded from version 0.84 to 0.88.
327 "CPANPLUS::Dist::Build"
329 Upgraded from version 0.06_02 to 0.36.
330 "Cwd"
332 Upgraded from version 3.25_01 to 3.30.
333 "Data::Dumper"
335 Upgraded from version 2.121_14 to 2.124.
336 "DB"
338 Upgraded from version 1.01 to 1.02.
339 "DB_File"
341 Upgraded from version 1.816_1 to 1.820.
342 "Devel::PPPort"
344 Upgraded from version 3.13 to 3.19.
345 "Digest::MD5"
347 Upgraded from version 2.36_01 to 2.39.
348 "Digest::SHA"
350 Upgraded from version 5.45 to 5.47.
351 "DirHandle"
353 Upgraded from version 1.01 to 1.03.
354 "Dumpvalue"
356 Upgraded from version 1.12 to 1.13.
357 "DynaLoader"
359 Upgraded from version 1.08 to 1.10.
360 "Encode"
362 Upgraded from version 2.23 to 2.35.
363 "Errno"
365 Upgraded from version 1.10 to 1.11.
366 "Exporter"
368 Upgraded from version 5.62 to 5.63.
369 "ExtUtils::CBuilder"
371 Upgraded from version 0.21 to 0.2602.
372 "ExtUtils::Command"
374 Upgraded from version 1.13 to 1.16.
375 "ExtUtils::Constant"
377 Upgraded from 0.20 to 0.22. (Note that neither of these versions
378 are available on CPAN.)
379 "ExtUtils::Embed"
381 Upgraded from version 1.27 to 1.28.
382 "ExtUtils::Install"
384 Upgraded from version 1.44 to 1.54.
385 "ExtUtils::MakeMaker"
387 Upgraded from version 6.42 to 6.55_02.
388 Note that "ExtUtils::MakeMaker::bytes" and
390 "ExtUtils::MakeMaker::vmsish" have been removed from this
391 distribution.
392 "ExtUtils::Manifest"
394 Upgraded from version 1.51_01 to 1.56.
395 "ExtUtils::ParseXS"
397 Upgraded from version 2.18_02 to 2.2002.
398 "Fatal"
400 Upgraded from version 1.05 to 2.06_01. See also the new pragma
401 "autodie".
402 "File::Basename"
404 Upgraded from version 2.76 to 2.77.
405 "File::Compare"
407 Upgraded from version 1.1005 to 1.1006.
408 "File::Copy"
410 Upgraded from version 2.11 to 2.14.
411 "File::Fetch"
413 Upgraded from version 0.14 to 0.20.
414 "File::Find"
416 Upgraded from version 1.12 to 1.14.
417 "File::Path"
419 Upgraded from version 2.04 to 2.07_03.
420 "File::Spec"
422 Upgraded from version 3.2501 to 3.30.
423 "File::stat"
425 Upgraded from version 1.00 to 1.01.
426 "File::Temp"
428 Upgraded from version 0.18 to 0.22.
429 "FileCache"
431 Upgraded from version 1.07 to 1.08.
432 "FileHandle"
434 Upgraded from version 2.01 to 2.02.
435 "Filter::Simple"
437 Upgraded from version 0.82 to 0.84.
438 "Filter::Util::Call"
440 Upgraded from version 1.07 to 1.08.
441 "FindBin"
443 Upgraded from version 1.49 to 1.50.
444 "GDBM_File"
446 Upgraded from version 1.08 to 1.09.
447 "Getopt::Long"
449 Upgraded from version 2.37 to 2.38.
450 "Hash::Util::FieldHash"
452 Upgraded from version 1.03 to 1.04. This fixes a memory leak.
453 "I18N::Collate"
455 Upgraded from version 1.00 to 1.01.
456 "IO"
458 Upgraded from version 1.23_01 to 1.25.
459 This makes non-blocking mode work on Windows in "IO::Socket::INET"
461 [CPAN #43573].
462 "IO::Compress::*"
464 Upgraded from version 2.008 to 2.020.
465 "IO::Dir"
467 Upgraded from version 1.06 to 1.07.
468 "IO::Handle"
470 Upgraded from version 1.27 to 1.28.
471 "IO::Socket"
473 Upgraded from version 1.30_01 to 1.31.
474 "IO::Zlib"
476 Upgraded from version 1.07 to 1.09.
477 "IPC::Cmd"
479 Upgraded from version 0.40_1 to 0.46.
480 "IPC::Open3"
482 Upgraded from version 1.02 to 1.04.
483 "IPC::SysV"
485 Upgraded from version 1.05 to 2.01.
486 "lib"
488 Upgraded from version 0.5565 to 0.62.
489 "List::Util"
491 Upgraded from version 1.19 to 1.21.
492 "Locale::MakeText"
494 Upgraded from version 1.12 to 1.13.
495 "Log::Message"
497 Upgraded from version 0.01 to 0.02.
498 "Math::BigFloat"
500 Upgraded from version 1.59 to 1.60.
501 "Math::BigInt"
503 Upgraded from version 1.88 to 1.89.
504 "Math::BigInt::FastCalc"
506 Upgraded from version 0.16 to 0.19.
507 "Math::BigRat"
509 Upgraded from version 0.21 to 0.22.
510 "Math::Complex"
512 Upgraded from version 1.37 to 1.56.
513 "Math::Trig"
515 Upgraded from version 1.04 to 1.20.
516 "Memoize"
518 Upgraded from version 1.01_02 to 1.01_03 (just a minor
519 documentation change).
520 "Module::Build"
522 Upgraded from version 0.2808_01 to 0.34_02.
523 "Module::CoreList"
525 Upgraded from version 2.13 to 2.18. This release no longer contains
526 the %Module::CoreList::patchlevel hash.
527 "Module::Load"
529 Upgraded from version 0.12 to 0.16.
530 "Module::Load::Conditional"
532 Upgraded from version 0.22 to 0.30.
533 "Module::Loaded"
535 Upgraded from version 0.01 to 0.02.
536 "Module::Pluggable"
538 Upgraded from version 3.6 to 3.9.
539 "NDBM_File"
541 Upgraded from version 1.07 to 1.08.
542 "Net::Ping"
544 Upgraded from version 2.33 to 2.36.
545 "NEXT"
547 Upgraded from version 0.60_01 to 0.64.
548 "Object::Accessor"
550 Upgraded from version 0.32 to 0.34.
551 "OS2::REXX"
553 Upgraded from version 1.03 to 1.04.
554 "Package::Constants"
556 Upgraded from version 0.01 to 0.02.
557 "PerlIO"
559 Upgraded from version 1.04 to 1.06.
560 "PerlIO::via"
562 Upgraded from version 0.04 to 0.07.
563 "Pod::Man"
565 Upgraded from version 2.16 to 2.22.
566 "Pod::Parser"
568 Upgraded from version 1.35 to 1.37.
569 "Pod::Simple"
571 Upgraded from version 3.05 to 3.07.
572 "Pod::Text"
574 Upgraded from version 3.08 to 3.13.
575 "POSIX"
577 Upgraded from version 1.13 to 1.17.
578 "Safe"
580 Upgraded from 2.12 to 2.18.
581 "Scalar::Util"
583 Upgraded from version 1.19 to 1.21.
584 "SelectSaver"
586 Upgraded from 1.01 to 1.02.
587 "SelfLoader"
589 Upgraded from 1.11 to 1.17.
590 "Socket"
592 Upgraded from 1.80 to 1.82.
593 "Storable"
595 Upgraded from 2.18 to 2.20.
596 "Switch"
598 Upgraded from version 2.13 to 2.14. Please see "Deprecations".
599 "Symbol"
601 Upgraded from version 1.06 to 1.07.
602 "Sys::Syslog"
604 Upgraded from version 0.22 to 0.27.
605 "Term::ANSIColor"
607 Upgraded from version 1.12 to 2.00.
608 "Term::ReadLine"
610 Upgraded from version 1.03 to 1.04.
611 "Term::UI"
613 Upgraded from version 0.18 to 0.20.
614 "Test::Harness"
616 Upgraded from version 2.64 to 3.17.
617 Note that one side-effect of the 2.x to 3.x upgrade is that the
619 experimental "Test::Harness::Straps" module (and its supporting
620 "Assert", "Iterator", "Point" and "Results" modules) have been
621 removed. If you still need this, then they are available in the
622 (unmaintained) "Test-Harness-Straps" distribution on CPAN.
623 "Test::Simple"
625 Upgraded from version 0.72 to 0.92.
626 "Text::ParseWords"
628 Upgraded from version 3.26 to 3.27.
629 "Text::Tabs"
631 Upgraded from version 2007.1117 to 2009.0305.
632 "Text::Wrap"
634 Upgraded from version 2006.1117 to 2009.0305.
635 "Thread::Queue"
637 Upgraded from version 2.00 to 2.11.
638 "Thread::Semaphore"
640 Upgraded from version 2.01 to 2.09.
641 "threads"
643 Upgraded from version 1.67 to 1.72.
644 "threads::shared"
646 Upgraded from version 1.14 to 1.29.
647 "Tie::RefHash"
649 Upgraded from version 1.37 to 1.38.
650 "Tie::StdHandle"
652 This has documentation changes, and has been assigned a version for
653 the first time: version 4.2.
654 "Time::HiRes"
656 Upgraded from version 1.9711 to 1.9719.
657 "Time::Local"
659 Upgraded from version 1.18 to 1.1901.
660 "Time::Piece"
662 Upgraded from version 1.12 to 1.15.
663 "Unicode::Normalize"
665 Upgraded from version 1.02 to 1.03.
666 "Unicode::UCD"
668 Upgraded from version 0.25 to 0.27.
669 "charinfo()" now works on Unified CJK code points added to later
671 versions of Unicode.
672 "casefold()" has new fields returned to provide both a simpler
674 interface and previously missing information. The old fields are
675 retained for backwards compatibility. Information about Turkic-
676 specific code points is now returned.
677 The documentation has been corrected and expanded.
679 "UNIVERSAL"
681 Upgraded from version 1.04 to 1.05.
682 "Win32"
684 Upgraded from version 0.34 to 0.39.
685 "Win32API::File"
687 Upgraded from version 0.1001_01 to 0.1101.
688 "XSLoader"
690 Upgraded from version 0.08 to 0.10.
691
693 h2ph
694 Now looks in "include-fixed" too, which is a recent addition to
695 gcc's search path.
696 h2xs
698 No longer incorrectly treats enum values like macros (Daniel Burr).
699 Now handles C++ style constants ("//") properly in enums. (A patch
701 from Rainer Weikusat was used; Daniel Burr also proposed a similar
702 fix).
703 perl5db.pl
705 "LVALUE" subroutines now work under the debugger.
706 The debugger now correctly handles proxy constant subroutines, and
708 subroutine stubs.
709 perlthanks
711 Perl 5.10.1 adds a new utility perlthanks, which is a variant of
712 perlbug, but for sending non-bug-reports to the authors and
713 maintainers of Perl. Getting nothing but bug reports can become a
714 bit demoralising: we'll see if this changes things.
715
717 perlhaiku
718 This contains instructions on how to build perl for the Haiku
719 platform.
720 perlmroapi
722 This describes the new interface for pluggable Method Resolution
723 Orders.
724 perlperf
726 This document, by Richard Foley, provides an introduction to the
727 use of performance and optimization techniques which can be used
728 with particular reference to perl programs.
729 perlrepository
731 This describes how to access the perl source using the git version
732 control system.
733 perlthanks
735 This describes the new perlthanks utility.
736
738 The various large "Changes*" files (which listed every change made to
739 perl over the last 18 years) have been removed, and replaced by a small
740 file, also called "Changes", which just explains how that same
741 information may be extracted from the git version control system.
742 The file Porting/patching.pod has been deleted, as it mainly described
744 interacting with the old Perforce-based repository, which is now
745 obsolete. Information still relevant has been moved to perlrepository.
746 perlapi, perlintern, perlmodlib and perltoc are now all generated at
748 build time, rather than being shipped as part of the release.
749
751 · A new internal cache means that "isa()" will often be faster.
752 · Under "use locale", the locale-relevant information is now cached
754 on read-only values, such as the list returned by "keys %hash".
755 This makes operations such as "sort keys %hash" in the scope of
756 "use locale" much faster.
757 · Empty "DESTROY" methods are no longer called.
759
761 ext/ reorganisation
762 The layout of directories in ext has been revised. Specifically, all
763 extensions are now flat, and at the top level, with "/" in pathnames
764 replaced by "-", so that ext/Data/Dumper/ is now ext/Data-Dumper/, etc.
765 The names of the extensions as specified to Configure, and as reported
766 by %Config::Config under the keys "dynamic_ext", "known_extensions",
767 "nonxs_ext" and "static_ext" have not changed, and still use "/". Hence
768 this change will not have any affect once perl is installed. However,
769 "Attribute::Handlers", "Safe" and "mro" have now become extensions in
770 their own right, so if you run Configure with options to specify an
771 exact list of extensions to build, you will need to change it to
772 account for this.
773 For 5.10.2, it is planned that many dual-life modules will have been
775 moved from lib to ext; again this will have no effect on an installed
776 perl, but will matter if you invoke Configure with a pre-canned list of
777 extensions to build.
778 Configuration improvements
780 If "vendorlib" and "vendorarch" are the same, then they are only added
781 to @INC once.
782 $Config{usedevel} and the C-level "PERL_USE_DEVEL" are now defined if
784 perl is built with "-Dusedevel".
785 Configure will enable use of "-fstack-protector", to provide protection
787 against stack-smashing attacks, if the compiler supports it.
788 Configure will now determine the correct prototypes for re-entrant
790 functions, and for "gconvert", if you are using a C++ compiler rather
791 than a C compiler.
792 On Unix, if you build from a tree containing a git repository, the
794 configuration process will note the commit hash you have checked out,
795 for display in the output of "perl -v" and "perl -V". Unpushed local
796 commits are automatically added to the list of local patches displayed
797 by "perl -V".
798 Compilation improvements
800 As part of the flattening of ext, all extensions on all platforms are
801 built by make_ext.pl. This replaces the Unix-specific
802 ext/util/make_ext, VMS-specific make_ext.com and Win32-specific
803 win32/buildext.pl.
804 Platform Specific Changes
806 AIX Removed libbsd for AIX 5L and 6.1. Only flock() was used from
807 libbsd.
808 Removed libgdbm for AIX 5L and 6.1. The libgdbm is delivered as an
810 optional package with the AIX Toolbox. Unfortunately the 64 bit
811 version is broken.
812 Hints changes mean that AIX 4.2 should work again.
814 Cygwin
816 On Cygwin we now strip the last number from the DLL. This has been
817 the behaviour in the cygwin.com build for years. The hints files
818 have been updated.
819 FreeBSD
821 The hints files now identify the correct threading libraries on
822 FreeBSD 7 and later.
823 Irix
825 We now work around a bizarre preprocessor bug in the Irix 6.5
826 compiler: "cc -E -" unfortunately goes into K&R mode, but "cc -E
827 file.c" doesn't.
828 Haiku
830 Patches from the Haiku maintainers have been merged in. Perl should
831 now build on Haiku.
832 MirOS BSD
834 Perl should now build on MirOS BSD.
835 NetBSD
837 Hints now supports versions 5.*.
838 Stratus VOS
840 Various changes from Stratus have been merged in.
841 Symbian
843 There is now support for Symbian S60 3.2 SDK and S60 5.0 SDK.
844 Win32
846 Improved message window handling means that "alarm" and "kill"
847 messages will no longer be dropped under race conditions.
848 VMS Reads from the in-memory temporary files of "PerlIO::scalar" used
850 to fail if $/ was set to a numeric reference (to indicate record-
851 style reads). This is now fixed.
852 VMS now supports "getgrgid".
854 Many improvements and cleanups have been made to the VMS file name
856 handling and conversion code.
857 Enabling the "PERL_VMS_POSIX_EXIT" logical name now encodes a POSIX
859 exit status in a VMS condition value for better interaction with
860 GNV's bash shell and other utilities that depend on POSIX exit
861 values. See "$?" in perlvms for details.
862
864 · 5.10.0 inadvertently disabled an optimisation, which caused a
865 measurable performance drop in list assignment, such as is often
866 used to assign function parameters from @_. The optimisation has
867 been re-instated, and the performance regression fixed.
868 · Fixed memory leak on "while (1) { map 1, 1 }" [RT #53038].
870 · Some potential coredumps in PerlIO fixed [RT #57322,54828].
872 · The debugger now works with lvalue subroutines.
874 · The debugger's "m" command was broken on modules that defined
876 constants [RT #61222].
877 · "crypt()" and string complement could return tainted values for
879 untainted arguments [RT #59998].
880 · The "-i.suffix" command-line switch now recreates the file using
882 restricted permissions, before changing its mode to match the
883 original file. This eliminates a potential race condition [RT
884 #60904].
885 · On some UNIX systems, the value in $? would not have the top bit
887 set ("$? & 128") even if the child core dumped.
888 · Under some circumstances, $^R could incorrectly become undefined
890 [RT #57042].
891 · (XS) In various hash functions, passing a pre-computed hash to when
893 the key is UTF-8 might result in an incorrect lookup.
894 · (XS) Including XSUB.h before perl.h gave a compile-time error [RT
896 #57176].
897 · "$object->isa('Foo')" would report false if the package "Foo"
899 didn't exist, even if the object's @ISA contained "Foo".
900 · Various bugs in the new-to 5.10.0 mro code, triggered by
902 manipulating @ISA, have been found and fixed.
903 · Bitwise operations on references could crash the interpreter, e.g.
905 "$x=\$y; $x |= "foo"" [RT #54956].
906 · Patterns including alternation might be sensitive to the internal
908 UTF-8 representation, e.g.
909 my $byte = chr(192);
911 my $utf8 = chr(192); utf8::upgrade($utf8);
912 $utf8 =~ /$byte|X}/i; # failed in 5.10.0
913 · Within UTF8-encoded Perl source files (i.e. where "use utf8" is in
915 effect), double-quoted literal strings could be corrupted where a
916 "\xNN", "\0NNN" or "\N{}" is followed by a literal character with
917 ordinal value greater than 255 [RT #59908].
918 · "B::Deparse" failed to correctly deparse various constructs:
920 "readpipe STRING" [RT #62428], "CORE::require(STRING)" [RT #62488],
921 "sub foo(_)" [RT #62484].
922 · Using "setpgrp()" with no arguments could corrupt the perl stack.
924 · The block form of "eval" is now specifically trappable by "Safe"
926 and "ops". Previously it was erroneously treated like string
927 "eval".
928 · In 5.10.0, the two characters "[~" were sometimes parsed as the
930 smart match operator ("~~") [RT #63854].
931 · In 5.10.0, the "*" quantifier in patterns was sometimes treated as
933 "{0,32767}" [RT #60034, #60464]. For example, this match would
934 fail:
935 ("ab" x 32768) =~ /^(ab)*$/
937 · "shmget" was limited to a 32 bit segment size on a 64 bit OS [RT
939 #63924].
940 · Using "next" or "last" to exit a "given" block no longer produces a
942 spurious warning like the following:
943 Exiting given via last at foo.pl line 123
945 · On Windows, '.\foo' and '..\foo' were treated differently than
947 './foo' and '../foo' by "do" and "require" [RT #63492].
948 · Assigning a format to a glob could corrupt the format; e.g.:
950 *bar=*foo{FORMAT}; # foo format now bad
952 · Attempting to coerce a typeglob to a string or number could cause
954 an assertion failure. The correct error message is now generated,
955 "Can't coerce GLOB to $type".
956 · Under "use filetest 'access'", "-x" was using the wrong access
958 mode. This has been fixed [RT #49003].
959 · "length" on a tied scalar that returned a Unicode value would not
961 be correct the first time. This has been fixed.
962 · Using an array "tie" inside in array "tie" could SEGV. This has
964 been fixed. [RT #51636]
965 · A race condition inside "PerlIOStdio_close()" has been identified
967 and fixed. This used to cause various threading issues, including
968 SEGVs.
969 · In "unpack", the use of "()" groups in scalar context was
971 internally placing a list on the interpreter's stack, which
972 manifested in various ways, including SEGVs. This is now fixed [RT
973 #50256].
974 · Magic was called twice in "substr", "\&$x", "tie $x, $m" and
976 "chop". These have all been fixed.
977 · A 5.10.0 optimisation to clear the temporary stack within the
979 implicit loop of "s///ge" has been reverted, as it turned out to be
980 the cause of obscure bugs in seemingly unrelated parts of the
981 interpreter [commit ef0d4e17921ee3de].
982 · The line numbers for warnings inside "elsif" are now correct.
984 · The ".." operator now works correctly with ranges whose ends are at
986 or close to the values of the smallest and largest integers.
987 · "binmode STDIN, ':raw'" could lead to segmentation faults on some
989 platforms. This has been fixed [RT #54828].
990 · An off-by-one error meant that "index $str, ..." was effectively
992 being executed as "index "$str\0", ...". This has been fixed [RT
993 #53746].
994 · Various leaks associated with named captures in regexes have been
996 fixed [RT #57024].
997 · A weak reference to a hash would leak. This was affecting "DBI" [RT
999 #56908].
1000 · Using (?|) in a regex could cause a segfault [RT #59734].
1002 · Use of a UTF-8 "tr//" within a closure could cause a segfault [RT
1004 #61520].
1005 · Calling "sv_chop()" or otherwise upgrading an SV could result in an
1007 unaligned 64-bit access on the SPARC architecture [RT #60574].
1008 · In the 5.10.0 release, "inc_version_list" would incorrectly list
1010 "5.10.*" after "5.8.*"; this affected the @INC search order [RT
1011 #67628].
1012 · In 5.10.0, "pack "a*", $tainted_value" returned a non-tainted value
1014 [RT #52552].
1015 · In 5.10.0, "printf" and "sprintf" could produce the fatal error
1017 "panic: utf8_mg_pos_cache_update" when printing UTF-8 strings [RT
1018 #62666].
1019 · In the 5.10.0 release, a dynamically created "AUTOLOAD" method
1021 might be missed (method cache issue) [RT #60220,60232].
1022 · In the 5.10.0 release, a combination of "use feature" and "//ee"
1024 could cause a memory leak [RT #63110].
1025 · "-C" on the shebang ("#!") line is once more permitted if it is
1027 also specified on the command line. "-C" on the shebang line used
1028 to be a silent no-op if it was not also on the command line, so
1029 perl 5.10.0 disallowed it, which broke some scripts. Now perl
1030 checks whether it is also on the command line and only dies if it
1031 is not [RT #67880].
1032 · In 5.10.0, certain types of re-entrant regular expression could
1034 crash, or cause the following assertion failure [RT #60508]:
1035 Assertion rx->sublen >= (s - rx->subbeg) + i failed
1037
1039 "panic: sv_chop %s"
1040 This new fatal error occurs when the C routine "Perl_sv_chop()" was
1041 passed a position that is not within the scalar's string buffer.
1042 This could be caused by buggy XS code, and at this point recovery
1043 is not possible.
1044 "Can't locate package %s for the parents of %s"
1046 This warning has been removed. In general, it only got produced in
1047 conjunction with other warnings, and removing it allowed an ISA
1048 lookup optimisation to be added.
1049 "v-string in use/require is non-portable"
1051 This warning has been removed.
1052 "Deep recursion on subroutine "%s""
1054 It is now possible to change the depth threshold for this warning
1055 from the default of 100, by recompiling the perl binary, setting
1056 the C pre-processor macro "PERL_SUB_DEPTH_WARN" to the desired
1057 value.
1058
1060 · The J.R.R. Tolkien quotes at the head of C source file have been
1061 checked and proper citations added, thanks to a patch from Tom
1062 Christiansen.
1063 · "vcroak()" now accepts a null first argument. In addition, a full
1065 audit was made of the "not NULL" compiler annotations, and those
1066 for several other internal functions were corrected.
1067 · New macros "dSAVEDERRNO", "dSAVE_ERRNO", "SAVE_ERRNO",
1069 "RESTORE_ERRNO" have been added to formalise the temporary saving
1070 of the "errno" variable.
1071 · The function "Perl_sv_insert_flags" has been added to augment
1073 "Perl_sv_insert".
1074 · The function "Perl_newSV_type(type)" has been added, equivalent to
1076 "Perl_newSV()" followed by "Perl_sv_upgrade(type)".
1077 · The function "Perl_newSVpvn_flags()" has been added, equivalent to
1079 "Perl_newSVpvn()" and then performing the action relevant to the
1080 flag.
1081 Two flag bits are currently supported.
1083 "SVf_UTF8"
1085 This will call "SvUTF8_on()" for you. (Note that this does not
1086 convert an sequence of ISO 8859-1 characters to UTF-8). A
1087 wrapper, "newSVpvn_utf8()" is available for this.
1088 "SVs_TEMP"
1090 Call "sv_2mortal()" on the new SV.
1091 There is also a wrapper that takes constant strings,
1093 "newSVpvs_flags()".
1094 · The function "Perl_croak_xs_usage" has been added as a wrapper to
1096 "Perl_croak".
1097 · The functions "PerlIO_find_layer" and "PerlIO_list_alloc" are now
1099 exported.
1100 · "PL_na" has been exterminated from the core code, replaced by local
1102 STRLEN temporaries, or "*_nolen()" calls. Either approach is faster
1103 than "PL_na", which is a pointer deference into the interpreter
1104 structure under ithreads, and a global variable otherwise.
1105 · "Perl_mg_free()" used to leave freed memory accessible via
1107 SvMAGIC() on the scalar. It now updates the linked list to remove
1108 each piece of magic as it is freed.
1109 · Under ithreads, the regex in "PL_reg_curpm" is now reference
1111 counted. This eliminates a lot of hackish workarounds to cope with
1112 it not being reference counted.
1113 · "Perl_mg_magical()" would sometimes incorrectly turn on
1115 "SvRMAGICAL()". This has been fixed.
1116 · The public IV and NV flags are now not set if the string value has
1118 trailing "garbage". This behaviour is consistent with not setting
1119 the public IV or NV flags if the value is out of range for the
1120 type.
1121 · SV allocation tracing has been added to the diagnostics enabled by
1123 "-Dm". The tracing can alternatively output via the "PERL_MEM_LOG"
1124 mechanism, if that was enabled when the perl binary was compiled.
1125 · Uses of "Nullav", "Nullcv", "Nullhv", "Nullop", "Nullsv" etc have
1127 been replaced by "NULL" in the core code, and non-dual-life
1128 modules, as "NULL" is clearer to those unfamiliar with the core
1129 code.
1130 · A macro MUTABLE_PTR(p) has been added, which on (non-pedantic) gcc
1132 will not cast away "const", returning a "void *". Macros
1133 "MUTABLE_SV(av)", "MUTABLE_SV(cv)" etc build on this, casting to
1134 "AV *" etc without casting away "const". This allows proper
1135 compile-time auditing of "const" correctness in the core, and
1136 helped picked up some errors (now fixed).
1137 · Macros "mPUSHs()" and "mXPUSHs()" have been added, for pushing SVs
1139 on the stack and mortalizing them.
1140 · Use of the private structure "mro_meta" has changed slightly.
1142 Nothing outside the core should be accessing this directly anyway.
1143 · A new tool, "Porting/expand-macro.pl" has been added, that allows
1145 you to view how a C preprocessor macro would be expanded when
1146 compiled. This is handy when trying to decode the macro hell that
1147 is the perl guts.
1148
1150 Many modules updated from CPAN incorporate new tests.
1151 Several tests that have the potential to hang forever if they fail now
1153 incorporate a "watchdog" functionality that will kill them after a
1154 timeout, which helps ensure that "make test" and "make test_harness"
1155 run to completion automatically. (Jerry Hedden).
1156 Some core-specific tests have been added:
1158 t/comp/retainedlines.t
1160 Check that the debugger can retain source lines from "eval".
1161 t/io/perlio_fail.t
1163 Check that bad layers fail.
1164 t/io/perlio_leaks.t
1166 Check that PerlIO layers are not leaking.
1167 t/io/perlio_open.t
1169 Check that certain special forms of open work.
1170 t/io/perlio.t
1172 General PerlIO tests.
1173 t/io/pvbm.t
1175 Check that there is no unexpected interaction between the internal
1176 types "PVBM" and "PVGV".
1177 t/mro/package_aliases.t
1179 Check that mro works properly in the presence of aliased packages.
1180 t/op/dbm.t
1182 Tests for "dbmopen" and "dbmclose".
1183 t/op/index_thr.t
1185 Tests for the interaction of "index" and threads.
1186 t/op/pat_thr.t
1188 Tests for the interaction of esoteric patterns and threads.
1189 t/op/qr_gc.t
1191 Test that "qr" doesn't leak.
1192 t/op/reg_email_thr.t
1194 Tests for the interaction of regex recursion and threads.
1195 t/op/regexp_qr_embed_thr.t
1197 Tests for the interaction of patterns with embedded "qr//" and
1198 threads.
1199 t/op/regexp_unicode_prop.t
1201 Tests for Unicode properties in regular expressions.
1202 t/op/regexp_unicode_prop_thr.t
1204 Tests for the interaction of Unicode properties and threads.
1205 t/op/reg_nc_tie.t
1207 Test the tied methods of "Tie::Hash::NamedCapture".
1208 t/op/reg_posixcc.t
1210 Check that POSIX character classes behave consistently.
1211 t/op/re.t
1213 Check that exportable "re" functions in universal.c work.
1214 t/op/setpgrpstack.t
1216 Check that "setpgrp" works.
1217 t/op/substr_thr.t
1219 Tests for the interaction of "substr" and threads.
1220 t/op/upgrade.t
1222 Check that upgrading and assigning scalars works.
1223 t/uni/lex_utf8.t
1225 Check that Unicode in the lexer works.
1226 t/uni/tie.t
1228 Check that Unicode and "tie" work.
1229
1231 This is a list of some significant unfixed bugs, which are regressions
1232 from either 5.10.0 or 5.8.x.
1233 · "List::Util::first" misbehaves in the presence of a lexical $_
1235 (typically introduced by "my $_" or implicitly by "given"). The
1236 variable which gets set for each iteration is the package variable
1237 $_, not the lexical $_ [RT #67694].
1238 A similar issue may occur in other modules that provide functions
1240 which take a block as their first argument, like
1241 foo { ... $_ ...} list
1243 · The "charnames" pragma may generate a run-time error when a regex
1245 is interpolated [RT #56444]:
1246 use charnames ':full';
1248 my $r1 = qr/\N{THAI CHARACTER SARA I}/;
1249 "foo" =~ $r1; # okay
1250 "foo" =~ /$r1+/; # runtime error
1251 A workaround is to generate the character outside of the regex:
1253 my $a = "\N{THAI CHARACTER SARA I}";
1255 my $r1 = qr/$a/;
1256 · Some regexes may run much more slowly when run in a child thread
1258 compared with the thread the pattern was compiled into [RT #55600].
1259
1261 The following items are now deprecated.
1262 · "Switch" is buggy and should be avoided. From perl 5.11.0 onwards,
1264 it is intended that any use of the core version of this module will
1265 emit a warning, and that the module will eventually be removed from
1266 the core (probably in perl 5.14.0). See "Switch statements" in
1267 perlsyn for its replacement.
1268 · "suidperl" will be removed in 5.12.0. This provides a mechanism to
1270 emulate setuid permission bits on systems that don't support it
1271 properly.
1272
1274 Some of the work in this release was funded by a TPF grant.
1275 Nicholas Clark officially retired from maintenance pumpking duty at the
1277 end of 2008; however in reality he has put much effort in since then to
1278 help get 5.10.1 into a fit state to be released, including writing a
1279 considerable chunk of this perldelta.
1280 Steffen Mueller and David Golden in particular helped getting CPAN
1282 modules polished and synchronised with their in-core equivalents.
1283 Craig Berry was tireless in getting maint to run under VMS, no matter
1285 how many times we broke it for him.
1286 The other core committers contributed most of the changes, and applied
1288 most of the patches sent in by the hundreds of contributors listed in
1289 AUTHORS.
1290 (Sorry to all the people I haven't mentioned by name).
1292 Finally, thanks to Larry Wall, without whom none of this would be
1294 necessary.
1295
1297 If you find what you think is a bug, you might check the articles
1298 recently posted to the comp.lang.perl.misc newsgroup and the perl bug
1299 database at http://rt.perl.org/perlbug/ . There may also be
1300 information at http://www.perl.org/ , the Perl Home Page.
1301 If you believe you have an unreported bug, please run the perlbug
1303 program included with your release. Be sure to trim your bug down to a
1304 tiny but sufficient test case. Your bug report, along with the output
1305 of "perl -V", will be sent off to perlbug@perl.org to be analysed by
1306 the Perl porting team.
1307 If the bug you are reporting has security implications, which make it
1309 inappropriate to send to a publicly archived mailing list, then please
1310 send it to perl5-security-report@perl.org. This points to a closed
1311 subscription unarchived mailing list, which includes all the core
1312 committers, who be able to help assess the impact of issues, figure out
1313 a resolution, and help co-ordinate the release of patches to mitigate
1314 or fix the problem across all platforms on which Perl is supported.
1315 Please only use this address for security issues in the Perl core, not
1316 for modules independently distributed on CPAN.
1317
1319 The Changes file for an explanation of how to view exhaustive details
1320 on what changed.
1321 The INSTALL file for how to build Perl.
1323 The README file for general stuff.
1325 The Artistic and Copying files for copyright information.
1327perl v5.10.1 2009-08-22 PERLDELTA(1)