1PERL5200DELTA(1) Perl Programmers Reference Guide PERL5200DELTA(1)
2
6 perl5200delta - what is new for perl v5.20.0
7
9 This document describes differences between the 5.18.0 release and the
10 5.20.0 release.
11 If you are upgrading from an earlier release such as 5.16.0, first read
13 perl5180delta, which describes differences between 5.16.0 and 5.18.0.
14
16 Experimental Subroutine signatures
17 Declarative syntax to unwrap argument list into lexical variables.
18 "sub foo ($a,$b) {...}" checks the number of arguments and puts the
19 arguments into lexical variables. Signatures are not equivalent to the
20 existing idiom of "sub foo { my($a,$b) = @_; ... }". Signatures are
21 only available by enabling a non-default feature, and generate warnings
22 about being experimental. The syntactic clash with prototypes is
23 managed by disabling the short prototype syntax when signatures are
24 enabled.
25 See "Signatures" in perlsub for details.
27 "sub"s now take a "prototype" attribute
29 When declaring or defining a "sub", the prototype can now be specified
30 inside of a "prototype" attribute instead of in parens following the
31 name.
32 For example, "sub foo($$){}" could be rewritten as "sub foo :
34 prototype($$){}".
35 More consistent prototype parsing
37 Multiple semicolons in subroutine prototypes have long been tolerated
38 and treated as a single semicolon. There was one case where this did
39 not happen. A subroutine whose prototype begins with "*" or ";*" can
40 affect whether a bareword is considered a method name or sub call.
41 This now applies also to ";;;*".
42 Whitespace has long been allowed inside subroutine prototypes, so "sub(
44 $ $ )" is equivalent to "sub($$)", but until now it was stripped when
45 the subroutine was parsed. Hence, whitespace was not allowed in
46 prototypes set by "Scalar::Util::set_prototype". Now it is permitted,
47 and the parser no longer strips whitespace. This means "prototype
48 &mysub" returns the original prototype, whitespace and all.
49 "rand" now uses a consistent random number generator
51 Previously perl would use a platform specific random number generator,
52 varying between the libc rand(), random() or drand48().
53 This meant that the quality of perl's random numbers would vary from
55 platform to platform, from the 15 bits of rand() on Windows to 48-bits
56 on POSIX platforms such as Linux with drand48().
57 Perl now uses its own internal drand48() implementation on all
59 platforms. This does not make perl's "rand" cryptographically secure.
60 [perl #115928]
61 New slice syntax
63 The new %hash{...} and %array[...] syntax returns a list of key/value
64 (or index/value) pairs. See "Key/Value Hash Slices" in perldata.
65 Experimental Postfix Dereferencing
67 When the "postderef" feature is in effect, the following syntactical
68 equivalencies are set up:
69 $sref->$*; # same as ${ $sref } # interpolates
71 $aref->@*; # same as @{ $aref } # interpolates
72 $href->%*; # same as %{ $href }
73 $cref->&*; # same as &{ $cref }
74 $gref->**; # same as *{ $gref }
75 $aref->$#*; # same as $#{ $aref }
77 $gref->*{ $slot }; # same as *{ $gref }{ $slot }
79 $aref->@[ ... ]; # same as @$aref[ ... ] # interpolates
81 $href->@{ ... }; # same as @$href{ ... } # interpolates
82 $aref->%[ ... ]; # same as %$aref[ ... ]
83 $href->%{ ... }; # same as %$href{ ... }
84 Those marked as interpolating only interpolate if the associated
86 "postderef_qq" feature is also enabled. This feature is experimental
87 and will trigger "experimental::postderef"-category warnings when used,
88 unless they are suppressed.
89 For more information, consult the Postfix Dereference Syntax section of
91 perlref.
92 Unicode 6.3 now supported
94 Perl now supports and is shipped with Unicode 6.3 (though Perl may be
95 recompiled with any previous Unicode release as well). A detailed list
96 of Unicode 6.3 changes is at
97 <http://www.unicode.org/versions/Unicode6.3.0/>.
98 New "\p{Unicode}" regular expression pattern property
100 This is a synonym for "\p{Any}" and matches the set of Unicode-defined
101 code points 0 - 0x10FFFF.
102 Better 64-bit support
104 On 64-bit platforms, the internal array functions now use 64-bit
105 offsets, allowing Perl arrays to hold more than 2**31 elements, if you
106 have the memory available.
107 The regular expression engine now supports strings longer than 2**31
109 characters. [perl #112790, #116907]
110 The functions PerlIO_get_bufsiz, PerlIO_get_cnt, PerlIO_set_cnt and
112 PerlIO_set_ptrcnt now have SSize_t, rather than int, return values and
113 parameters.
114 "use locale" now works on UTF-8 locales
116 Until this release, only single-byte locales, such as the ISO 8859
117 series were supported. Now, the increasingly common multi-byte UTF-8
118 locales are also supported. A UTF-8 locale is one in which the
119 character set is Unicode and the encoding is UTF-8. The POSIX
120 "LC_CTYPE" category operations (case changing (like "lc()", "\U"), and
121 character classification ("\w", "\D", "qr/[[:punct:]]/")) under such a
122 locale work just as if not under locale, but instead as if under
123 "use feature 'unicode_strings'", except taint rules are followed.
124 Sorting remains by code point order in this release. [perl #56820].
125 "use locale" now compiles on systems without locale ability
127 Previously doing this caused the program to not compile. Within its
128 scope the program behaves as if in the "C" locale. Thus programs
129 written for platforms that support locales can run on locale-less
130 platforms without change. Attempts to change the locale away from the
131 "C" locale will, of course, fail.
132 More locale initialization fallback options
134 If there was an error with locales during Perl start-up, it immediately
135 gave up and tried to use the "C" locale. Now it first tries using
136 other locales given by the environment variables, as detailed in
137 "ENVIRONMENT" in perllocale. For example, if "LC_ALL" and "LANG" are
138 both set, and using the "LC_ALL" locale fails, Perl will now try the
139 "LANG" locale, and only if that fails, will it fall back to "C". On
140 Windows machines, Perl will try, ahead of using "C", the system default
141 locale if all the locales given by environment variables fail.
142 "-DL" runtime option now added for tracing locale setting
144 This is designed for Perl core developers to aid in field debugging
145 bugs regarding locales.
146 -F now implies -a and -a implies -n
148 Previously -F without -a was a no-op, and -a without -n or -p was a no-
149 op, with this change, if you supply -F then both -a and -n are implied
150 and if you supply -a then -n is implied.
151 You can still use -p for its extra behaviour. [perl #116190]
153 $a and $b warnings exemption
155 The special variables $a and $b, used in "sort", are now exempt from
156 "used once" warnings, even where "sort" is not used. This makes it
157 easier for CPAN modules to provide functions using $a and $b for
158 similar purposes. [perl #120462]
159
161 Avoid possible read of free()d memory during parsing
162 It was possible that free()d memory could be read during parsing in the
163 unusual circumstance of the Perl program ending with a heredoc and the
164 last line of the file on disk having no terminating newline character.
165 This has now been fixed.
166
168 "do" can no longer be used to call subroutines
169 The "do SUBROUTINE(LIST)" form has resulted in a deprecation warning
170 since Perl v5.0.0, and is now a syntax error.
171 Quote-like escape changes
173 The character after "\c" in a double-quoted string ("..." or qq(...))
174 or regular expression must now be a printable character and may not be
175 "{".
176 A literal "{" after "\B" or "\b" is now fatal.
178 These were deprecated in perl v5.14.0.
180 Tainting happens under more circumstances; now conforms to documentation
182 This affects regular expression matching and changing the case of a
183 string ("lc", "\U", etc.) within the scope of "use locale". The result
184 is now tainted based on the operation, no matter what the contents of
185 the string were, as the documentation (perlsec, "SECURITY" in
186 perllocale) indicates it should. Previously, for the case change
187 operation, if the string contained no characters whose case change
188 could be affected by the locale, the result would not be tainted. For
189 example, the result of "uc()" on an empty string or one containing only
190 above-Latin1 code points is now tainted, and wasn't before. This leads
191 to more consistent tainting results. Regular expression patterns taint
192 their non-binary results (like $&, $2) if and only if the pattern
193 contains elements whose matching depends on the current (potentially
194 tainted) locale. Like the case changing functions, the actual contents
195 of the string being matched now do not matter, whereas formerly it did.
196 For example, if the pattern contains a "\w", the results will be
197 tainted even if the match did not have to use that portion of the
198 pattern to succeed or fail, because what a "\w" matches depends on
199 locale. However, for example, a "." in a pattern will not enable
200 tainting, because the dot matches any single character, and what the
201 current locale is doesn't change in any way what matches and what
202 doesn't.
203 "\p{}", "\P{}" matching has changed for non-Unicode code points.
205 "\p{}" and "\P{}" are defined by Unicode only on Unicode-defined code
206 points ("U+0000" through "U+10FFFF"). Their behavior on matching these
207 legal Unicode code points is unchanged, but there are changes for code
208 points 0x110000 and above. Previously, Perl treated the result of
209 matching "\p{}" and "\P{}" against these as "undef", which translates
210 into "false". For "\P{}", this was then complemented into "true". A
211 warning was supposed to be raised when this happened. However, various
212 optimizations could prevent the warning, and the results were often
213 counter-intuitive, with both a match and its seeming complement being
214 false. Now all non-Unicode code points are treated as typical
215 unassigned Unicode code points. This generally is more Do-What-I-Mean.
216 A warning is raised only if the results are arguably different from a
217 strict Unicode approach, and from what Perl used to do. Code that
218 needs to be strictly Unicode compliant can make this warning fatal, and
219 then Perl always raises the warning.
220 Details are in "Beyond Unicode code points" in perlunicode.
222 "\p{All}" has been expanded to match all possible code points
224 The Perl-defined regular expression pattern element "\p{All}", unused
225 on CPAN, used to match just the Unicode code points; now it matches all
226 possible code points; that is, it is equivalent to "qr/./s". Thus
227 "\p{All}" is no longer synonymous with "\p{Any}", which continues to
228 match just the Unicode code points, as Unicode says it should.
229 Data::Dumper's output may change
231 Depending on the data structures dumped and the settings set for
232 Data::Dumper, the dumped output may have changed from previous
233 versions.
234 If you have tests that depend on the exact output of Data::Dumper, they
236 may fail.
237 To avoid this problem in your code, test against the data structure
239 from evaluating the dumped structure, instead of the dump itself.
240 Locale decimal point character no longer leaks outside of "use locale"
242 scope
243 This is actually a bug fix, but some code has come to rely on the bug
244 being present, so this change is listed here. The current locale that
245 the program is running under is not supposed to be visible to Perl code
246 except within the scope of a "use locale". However, until now under
247 certain circumstances, the character used for a decimal point (often a
248 comma) leaked outside the scope. If your code is affected by this
249 change, simply add a "use locale".
250 Assignments of Windows sockets error codes to $! now prefer errno.h values
252 over WSAGetLastError() values
253 In previous versions of Perl, Windows sockets error codes as returned
254 by WSAGetLastError() were assigned to $!, and some constants such as
255 ECONNABORTED, not in errno.h in VC++ (or the various Windows ports of
256 gcc) were defined to corresponding WSAE* values to allow $! to be
257 tested against the E* constants exported by Errno and POSIX.
258 This worked well until VC++ 2010 and later, which introduced new E*
260 constants with values > 100 into errno.h, including some being
261 (re)defined by perl to WSAE* values. That caused problems when linking
262 XS code against other libraries which used the original definitions of
263 errno.h constants.
264 To avoid this incompatibility, perl now maps WSAE* error codes to E*
266 values where possible, and assigns those values to $!. The E*
267 constants exported by Errno and POSIX are updated to match so that
268 testing $! against them, wherever previously possible, will continue to
269 work as expected, and all E* constants found in errno.h are now
270 exported from those modules with their original errno.h values.
271 In order to avoid breakage in existing Perl code which assigns WSAE*
273 values to $!, perl now intercepts the assignment and performs the same
274 mapping to E* values as it uses internally when assigning to $! itself.
275 However, one backwards-incompatibility remains: existing Perl code
277 which compares $! against the numeric values of the WSAE* error codes
278 that were previously assigned to $! will now be broken in those cases
279 where a corresponding E* value has been assigned instead. This is only
280 an issue for those E* values < 100, which were always exported from
281 Errno and POSIX with their original errno.h values, and therefore could
282 not be used for WSAE* error code tests (e.g. WSAEINVAL is 10022, but
283 the corresponding EINVAL is 22). (E* values > 100, if present, were
284 redefined to WSAE* values anyway, so compatibility can be achieved by
285 using the E* constants, which will work both before and after this
286 change, albeit using different numeric values under the hood.)
287 Functions "PerlIO_vsprintf" and "PerlIO_sprintf" have been removed
289 These two functions, undocumented, unused in CPAN, and problematic,
290 have been removed.
291
293 The "/\C/" character class
294 The "/\C/" regular expression character class is deprecated. From perl
295 5.22 onwards it will generate a warning, and from perl 5.24 onwards it
296 will be a regular expression compiler error. If you need to examine the
297 individual bytes that make up a UTF8-encoded character, then use
298 "utf8::encode()" on the string (or a copy) first.
299 Literal control characters in variable names
301 This deprecation affects things like $\cT, where \cT is a literal
302 control (such as a "NAK" or "NEGATIVE ACKNOWLEDGE" character) in the
303 source code. Surprisingly, it appears that originally this was
304 intended as the canonical way of accessing variables like $^T, with the
305 caret form only being added as an alternative.
306 The literal control form is being deprecated for two main reasons. It
308 has what are likely unfixable bugs, such as $\cI not working as an
309 alias for $^I, and their usage not being portable to non-ASCII
310 platforms: While $^T will work everywhere, \cT is whitespace in EBCDIC.
311 [perl #119123]
312 References to non-integers and non-positive integers in $/
314 Setting $/ to a reference to zero or a reference to a negative integer
315 is now deprecated, and will behave exactly as though it was set to
316 "undef". If you want slurp behavior set $/ to "undef" explicitly.
317 Setting $/ to a reference to a non integer is now forbidden and will
319 throw an error. Perl has never documented what would happen in this
320 context and while it used to behave the same as setting $/ to the
321 address of the references in future it may behave differently, so we
322 have forbidden this usage.
323 Character matching routines in POSIX
325 Use of any of these functions in the "POSIX" module is now deprecated:
326 "isalnum", "isalpha", "iscntrl", "isdigit", "isgraph", "islower",
327 "isprint", "ispunct", "isspace", "isupper", and "isxdigit". The
328 functions are buggy and don't work on UTF-8 encoded strings. See their
329 entries in POSIX for more information.
330 A warning is raised on the first call to any of them from each place in
332 the code that they are called. (Hence a repeated statement in a loop
333 will raise just the one warning.)
334 Interpreter-based threads are now discouraged
336 The "interpreter-based threads" provided by Perl are not the fast,
337 lightweight system for multitasking that one might expect or hope for.
338 Threads are implemented in a way that make them easy to misuse. Few
339 people know how to use them correctly or will be able to provide help.
340 The use of interpreter-based threads in perl is officially discouraged.
342 Module removals
344 The following modules will be removed from the core distribution in a
345 future release, and will at that time need to be installed from CPAN.
346 Distributions on CPAN which require these modules will need to list
347 them as prerequisites.
348 The core versions of these modules will now issue "deprecated"-category
350 warnings to alert you to this fact. To silence these deprecation
351 warnings, install the modules in question from CPAN.
352 Note that the planned removal of these modules from core does not
354 reflect a judgement about the quality of the code and should not be
355 taken as a suggestion that their use be halted. Their disinclusion
356 from core primarily hinges on their necessity to bootstrapping a fully
357 functional, CPAN-capable Perl installation, not on concerns over their
358 design.
359 CGI and its associated CGI:: packages
361 inc::latest
362 Package::Constants
363 Module::Build and its associated Module::Build:: packages
364 Utility removals
366 The following utilities will be removed from the core distribution in a
367 future release, and will at that time need to be installed from CPAN.
368 find2perl
370 s2p
371 a2p
372
374 • Perl has a new copy-on-write mechanism that avoids the need to copy
375 the internal string buffer when assigning from one scalar to
376 another. This makes copying large strings appear much faster.
377 Modifying one of the two (or more) strings after an assignment will
378 force a copy internally. This makes it unnecessary to pass strings
379 by reference for efficiency.
380 This feature was already available in 5.18.0, but wasn't enabled by
382 default. It is the default now, and so you no longer need build
383 perl with the Configure argument:
384 -Accflags=-DPERL_NEW_COPY_ON_WRITE
386 It can be disabled (for now) in a perl build with:
388 -Accflags=-DPERL_NO_COW
390 On some operating systems Perl can be compiled in such a way that
392 any attempt to modify string buffers shared by multiple SVs will
393 crash. This way XS authors can test that their modules handle
394 copy-on-write scalars correctly. See "Copy on Write" in perlguts
395 for detail.
396 • Perl has an optimizer for regular expression patterns. It analyzes
398 the pattern to find things such as the minimum length a string has
399 to be to match, etc. It now better handles code points that are
400 above the Latin1 range.
401 • Executing a regex that contains the "^" anchor (or its variant
403 under the "/m" flag) has been made much faster in several
404 situations.
405 • Precomputed hash values are now used in more places during method
407 lookup.
408 • Constant hash key lookups ($hash{key} as opposed to $hash{$key})
410 have long had the internal hash value computed at compile time, to
411 speed up lookup. This optimisation has only now been applied to
412 hash slices as well.
413 • Combined "and" and "or" operators in void context, like those
415 generated for "unless ($a && $b)" and "if ($a || b)" now short
416 circuit directly to the end of the statement. [perl #120128]
417 • In certain situations, when "return" is the last statement in a
419 subroutine's main scope, it will be optimized out. This means code
420 like:
421 sub baz { return $cat; }
423 will now behave like:
425 sub baz { $cat; }
427 which is notably faster.
429 [perl #120765]
431 • Code like:
433 my $x; # or @x, %x
435 my $y;
436 is now optimized to:
438 my ($x, $y);
440 In combination with the padrange optimization introduced in
442 v5.18.0, this means longer uninitialized my variable statements are
443 also optimized, so:
444 my $x; my @y; my %z;
446 becomes:
448 my ($x, @y, %z);
450 [perl #121077]
452 • The creation of certain sorts of lists, including array and hash
454 slices, is now faster.
455 • The optimisation for arrays indexed with a small constant integer
457 is now applied for integers in the range -128..127, rather than
458 0..255. This should speed up Perl code using expressions like
459 $x[-1], at the expense of (presumably much rarer) code using
460 expressions like $x[200].
461 • The first iteration over a large hash (using "keys" or "each") is
463 now faster. This is achieved by preallocating the hash's internal
464 iterator state, rather than lazily creating it when the hash is
465 first iterated. (For small hashes, the iterator is still created
466 only when first needed. The assumption is that small hashes are
467 more likely to be used as objects, and therefore never allocated.
468 For large hashes, that's less likely to be true, and the cost of
469 allocating the iterator is swamped by the cost of allocating space
470 for the hash itself.)
471 • When doing a global regex match on a string that came from the
473 "readline" or "<>" operator, the data is no longer copied
474 unnecessarily. [perl #121259]
475 • Dereferencing (as in "$obj->[0]" or "$obj->{k}") is now faster when
477 $obj is an instance of a class that has overloaded methods, but
478 doesn't overload any of the dereferencing methods "@{}", "%{}", and
479 so on.
480 • Perl's optimiser no longer skips optimising code that follows
482 certain "eval {}" expressions (including those with an apparent
483 infinite loop).
484 • The implementation now does a better job of avoiding meaningless
486 work at runtime. Internal effect-free "null" operations (created as
487 a side-effect of parsing Perl programs) are normally deleted during
488 compilation. That deletion is now applied in some situations that
489 weren't previously handled.
490 • Perl now does less disk I/O when dealing with Unicode properties
492 that cover up to three ranges of consecutive code points.
493
495 New Modules and Pragmata
496 • experimental 0.007 has been added to the Perl core.
497 • IO::Socket::IP 0.29 has been added to the Perl core.
499 Updated Modules and Pragmata
501 • Archive::Tar has been upgraded from version 1.90 to 1.96.
502 • arybase has been upgraded from version 0.06 to 0.07.
504 • Attribute::Handlers has been upgraded from version 0.94 to 0.96.
506 • attributes has been upgraded from version 0.21 to 0.22.
508 • autodie has been upgraded from version 2.13 to 2.23.
510 • AutoLoader has been upgraded from version 5.73 to 5.74.
512 • autouse has been upgraded from version 1.07 to 1.08.
514 • B has been upgraded from version 1.42 to 1.48.
516 • B::Concise has been upgraded from version 0.95 to 0.992.
518 • B::Debug has been upgraded from version 1.18 to 1.19.
520 • B::Deparse has been upgraded from version 1.20 to 1.26.
522 • base has been upgraded from version 2.18 to 2.22.
524 • Benchmark has been upgraded from version 1.15 to 1.18.
526 • bignum has been upgraded from version 0.33 to 0.37.
528 • Carp has been upgraded from version 1.29 to 1.3301.
530 • CGI has been upgraded from version 3.63 to 3.65. NOTE: CGI is
532 deprecated and may be removed from a future version of Perl.
533 • charnames has been upgraded from version 1.36 to 1.40.
535 • Class::Struct has been upgraded from version 0.64 to 0.65.
537 • Compress::Raw::Bzip2 has been upgraded from version 2.060 to 2.064.
539 • Compress::Raw::Zlib has been upgraded from version 2.060 to 2.065.
541 • Config::Perl::V has been upgraded from version 0.17 to 0.20.
543 • constant has been upgraded from version 1.27 to 1.31.
545 • CPAN has been upgraded from version 2.00 to 2.05.
547 • CPAN::Meta has been upgraded from version 2.120921 to 2.140640.
549 • CPAN::Meta::Requirements has been upgraded from version 2.122 to
551 2.125.
552 • CPAN::Meta::YAML has been upgraded from version 0.008 to 0.012.
554 • Data::Dumper has been upgraded from version 2.145 to 2.151.
556 • DB has been upgraded from version 1.04 to 1.07.
558 • DB_File has been upgraded from version 1.827 to 1.831.
560 • DBM_Filter has been upgraded from version 0.05 to 0.06.
562 • deprecate has been upgraded from version 0.02 to 0.03.
564 • Devel::Peek has been upgraded from version 1.11 to 1.16.
566 • Devel::PPPort has been upgraded from version 3.20 to 3.21.
568 • diagnostics has been upgraded from version 1.31 to 1.34.
570 • Digest::MD5 has been upgraded from version 2.52 to 2.53.
572 • Digest::SHA has been upgraded from version 5.84 to 5.88.
574 • DynaLoader has been upgraded from version 1.18 to 1.25.
576 • Encode has been upgraded from version 2.49 to 2.60.
578 • encoding has been upgraded from version 2.6_01 to 2.12.
580 • English has been upgraded from version 1.06 to 1.09.
582 $OLD_PERL_VERSION was added as an alias of $].
584 • Errno has been upgraded from version 1.18 to 1.20_03.
586 • Exporter has been upgraded from version 5.68 to 5.70.
588 • ExtUtils::CBuilder has been upgraded from version 0.280210 to
590 0.280216.
591 • ExtUtils::Command has been upgraded from version 1.17 to 1.18.
593 • ExtUtils::Embed has been upgraded from version 1.30 to 1.32.
595 • ExtUtils::Install has been upgraded from version 1.59 to 1.67.
597 • ExtUtils::MakeMaker has been upgraded from version 6.66 to 6.98.
599 • ExtUtils::Miniperl has been upgraded from version to 1.01.
601 • ExtUtils::ParseXS has been upgraded from version 3.18 to 3.24.
603 • ExtUtils::Typemaps has been upgraded from version 3.19 to 3.24.
605 • ExtUtils::XSSymSet has been upgraded from version 1.2 to 1.3.
607 • feature has been upgraded from version 1.32 to 1.36.
609 • fields has been upgraded from version 2.16 to 2.17.
611 • File::Basename has been upgraded from version 2.84 to 2.85.
613 • File::Copy has been upgraded from version 2.26 to 2.29.
615 • File::DosGlob has been upgraded from version 1.10 to 1.12.
617 • File::Fetch has been upgraded from version 0.38 to 0.48.
619 • File::Find has been upgraded from version 1.23 to 1.27.
621 • File::Glob has been upgraded from version 1.20 to 1.23.
623 • File::Spec has been upgraded from version 3.40 to 3.47.
625 • File::Temp has been upgraded from version 0.23 to 0.2304.
627 • FileCache has been upgraded from version 1.08 to 1.09.
629 • Filter::Simple has been upgraded from version 0.89 to 0.91.
631 • Filter::Util::Call has been upgraded from version 1.45 to 1.49.
633 • Getopt::Long has been upgraded from version 2.39 to 2.42.
635 • Getopt::Std has been upgraded from version 1.07 to 1.10.
637 • Hash::Util::FieldHash has been upgraded from version 1.10 to 1.15.
639 • HTTP::Tiny has been upgraded from version 0.025 to 0.043.
641 • I18N::Langinfo has been upgraded from version 0.10 to 0.11.
643 • I18N::LangTags has been upgraded from version 0.39 to 0.40.
645 • if has been upgraded from version 0.0602 to 0.0603.
647 • inc::latest has been upgraded from version 0.4003 to 0.4205. NOTE:
649 inc::latest is deprecated and may be removed from a future version
650 of Perl.
651 • integer has been upgraded from version 1.00 to 1.01.
653 • IO has been upgraded from version 1.28 to 1.31.
655 • IO::Compress::Gzip and friends have been upgraded from version
657 2.060 to 2.064.
658 • IPC::Cmd has been upgraded from version 0.80 to 0.92.
660 • IPC::Open3 has been upgraded from version 1.13 to 1.16.
662 • IPC::SysV has been upgraded from version 2.03 to 2.04.
664 • JSON::PP has been upgraded from version 2.27202 to 2.27203.
666 • List::Util has been upgraded from version 1.27 to 1.38.
668 • locale has been upgraded from version 1.02 to 1.03.
670 • Locale::Codes has been upgraded from version 3.25 to 3.30.
672 • Locale::Maketext has been upgraded from version 1.23 to 1.25.
674 • Math::BigInt has been upgraded from version 1.9991 to 1.9993.
676 • Math::BigInt::FastCalc has been upgraded from version 0.30 to 0.31.
678 • Math::BigRat has been upgraded from version 0.2604 to 0.2606.
680 • MIME::Base64 has been upgraded from version 3.13 to 3.14.
682 • Module::Build has been upgraded from version 0.4003 to 0.4205.
684 NOTE: Module::Build is deprecated and may be removed from a future
685 version of Perl.
686 • Module::CoreList has been upgraded from version 2.89 to 3.10.
688 • Module::Load has been upgraded from version 0.24 to 0.32.
690 • Module::Load::Conditional has been upgraded from version 0.54 to
692 0.62.
693 • Module::Metadata has been upgraded from version 1.000011 to
695 1.000019.
696 • mro has been upgraded from version 1.11 to 1.16.
698 • Net::Ping has been upgraded from version 2.41 to 2.43.
700 • Opcode has been upgraded from version 1.25 to 1.27.
702 • Package::Constants has been upgraded from version 0.02 to 0.04.
704 NOTE: Package::Constants is deprecated and may be removed from a
705 future version of Perl.
706 • Params::Check has been upgraded from version 0.36 to 0.38.
708 • parent has been upgraded from version 0.225 to 0.228.
710 • Parse::CPAN::Meta has been upgraded from version 1.4404 to 1.4414.
712 • Perl::OSType has been upgraded from version 1.003 to 1.007.
714 • perlfaq has been upgraded from version 5.0150042 to 5.0150044.
716 • PerlIO has been upgraded from version 1.07 to 1.09.
718 • PerlIO::encoding has been upgraded from version 0.16 to 0.18.
720 • PerlIO::scalar has been upgraded from version 0.16 to 0.18.
722 • PerlIO::via has been upgraded from version 0.12 to 0.14.
724 • Pod::Escapes has been upgraded from version 1.04 to 1.06.
726 • Pod::Functions has been upgraded from version 1.06 to 1.08.
728 • Pod::Html has been upgraded from version 1.18 to 1.21.
730 • Pod::Parser has been upgraded from version 1.60 to 1.62.
732 • Pod::Perldoc has been upgraded from version 3.19 to 3.23.
734 • Pod::Usage has been upgraded from version 1.61 to 1.63.
736 • POSIX has been upgraded from version 1.32 to 1.38_03.
738 • re has been upgraded from version 0.23 to 0.26.
740 • Safe has been upgraded from version 2.35 to 2.37.
742 • Scalar::Util has been upgraded from version 1.27 to 1.38.
744 • SDBM_File has been upgraded from version 1.09 to 1.11.
746 • Socket has been upgraded from version 2.009 to 2.013.
748 • Storable has been upgraded from version 2.41 to 2.49.
750 • strict has been upgraded from version 1.07 to 1.08.
752 • subs has been upgraded from version 1.01 to 1.02.
754 • Sys::Hostname has been upgraded from version 1.17 to 1.18.
756 • Sys::Syslog has been upgraded from version 0.32 to 0.33.
758 • Term::Cap has been upgraded from version 1.13 to 1.15.
760 • Term::ReadLine has been upgraded from version 1.12 to 1.14.
762 • Test::Harness has been upgraded from version 3.26 to 3.30.
764 • Test::Simple has been upgraded from version 0.98 to 1.001002.
766 • Text::ParseWords has been upgraded from version 3.28 to 3.29.
768 • Text::Tabs has been upgraded from version 2012.0818 to 2013.0523.
770 • Text::Wrap has been upgraded from version 2012.0818 to 2013.0523.
772 • Thread has been upgraded from version 3.02 to 3.04.
774 • Thread::Queue has been upgraded from version 3.02 to 3.05.
776 • threads has been upgraded from version 1.86 to 1.93.
778 • threads::shared has been upgraded from version 1.43 to 1.46.
780 • Tie::Array has been upgraded from version 1.05 to 1.06.
782 • Tie::File has been upgraded from version 0.99 to 1.00.
784 • Tie::Hash has been upgraded from version 1.04 to 1.05.
786 • Tie::Scalar has been upgraded from version 1.02 to 1.03.
788 • Tie::StdHandle has been upgraded from version 4.3 to 4.4.
790 • Time::HiRes has been upgraded from version 1.9725 to 1.9726.
792 • Time::Piece has been upgraded from version 1.20_01 to 1.27.
794 • Unicode::Collate has been upgraded from version 0.97 to 1.04.
796 • Unicode::Normalize has been upgraded from version 1.16 to 1.17.
798 • Unicode::UCD has been upgraded from version 0.51 to 0.57.
800 • utf8 has been upgraded from version 1.10 to 1.13.
802 • version has been upgraded from version 0.9902 to 0.9908.
804 • vmsish has been upgraded from version 1.03 to 1.04.
806 • warnings has been upgraded from version 1.18 to 1.23.
808 • Win32 has been upgraded from version 0.47 to 0.49.
810 • XS::Typemap has been upgraded from version 0.10 to 0.13.
812 • XSLoader has been upgraded from version 0.16 to 0.17.
814
816 New Documentation
817 perlrepository
818 This document was removed (actually, renamed perlgit and given a major
820 overhaul) in Perl v5.14, causing Perl documentation websites to show
821 the now out of date version in Perl v5.12 as the latest version. It
822 has now been restored in stub form, directing readers to current
823 information.
824 Changes to Existing Documentation
826 perldata
827 • New sections have been added to document the new index/value array
829 slice and key/value hash slice syntax.
830 perldebguts
832 • The "DB::goto" and "DB::lsub" debugger subroutines are now
834 documented. [perl #77680]
835 perlexperiment
837 • "\s" matching "\cK" is marked experimental.
839 • ithreads were accepted in v5.8.0 (but are discouraged as of
841 v5.20.0).
842 • Long doubles are not considered experimental.
844 • Code in regular expressions, regular expression backtracking verbs,
846 and lvalue subroutines are no longer listed as experimental. (This
847 also affects perlre and perlsub.)
848 perlfunc
850 • "chop" and "chomp" now note that they can reset the hash iterator.
852 • "exec"'s handling of arguments is now more clearly documented.
854 • "eval EXPR" now has caveats about expanding floating point numbers
856 in some locales.
857 • "goto EXPR" is now documented to handle an expression that evalutes
859 to a code reference as if it was "goto &$coderef". This behavior
860 is at least ten years old.
861 • Since Perl v5.10, it has been possible for subroutines in @INC to
863 return a reference to a scalar holding initial source code to
864 prepend to the file. This is now documented.
865 • The documentation of "ref" has been updated to recommend the use of
867 "blessed", "isa" and "reftype" when dealing with references to
868 blessed objects.
869 perlguts
871 • Numerous minor changes have been made to reflect changes made to
873 the perl internals in this release.
874 • New sections on Read-Only Values and Copy on Write have been added.
876 perlhack
878 • The Super Quick Patch Guide section has been updated.
880 perlhacktips
882 • The documentation has been updated to include some more examples of
884 "gdb" usage.
885 perllexwarn
887 • The perllexwarn documentation used to describe the hierarchy of
889 warning categories understood by the warnings pragma. That
890 description has now been moved to the warnings documentation
891 itself, leaving perllexwarn as a stub that points to it. This
892 change consolidates all documentation for lexical warnings in a
893 single place.
894 perllocale
896 • The documentation now mentions fc() and "\F", and includes many
898 clarifications and corrections in general.
899 perlop
901 • The language design of Perl has always called for monomorphic
903 operators. This is now mentioned explicitly.
904 perlopentut
906 • The "open" tutorial has been completely rewritten by Tom
908 Christiansen, and now focuses on covering only the basics, rather
909 than providing a comprehensive reference to all things openable.
910 This rewrite came as the result of a vigorous discussion on
911 perl5-porters kicked off by a set of improvements written by
912 Alexander Hartmaier to the existing perlopentut. A "more than you
913 ever wanted to know about "open"" document may follow in subsequent
914 versions of perl.
915 perlre
917 • The fact that the regexp engine makes no effort to call (?{}) and
919 (??{}) constructs any specified number of times (although it will
920 basically DWIM in case of a successful match) has been documented.
921 • The "/r" modifier (for non-destructive substitution) is now
923 documented. [perl #119151]
924 • The documentation for "/x" and "(?# comment)" has been expanded and
926 clarified.
927 perlreguts
929 • The documentation has been updated in the light of recent changes
931 to regcomp.c.
932 perlsub
934 • The need to predeclare recursive functions with prototypes in order
936 for the prototype to be honoured in the recursive call is now
937 documented. [perl #2726]
938 • A list of subroutine names used by the perl implementation is now
940 included. [perl #77680]
941 perltrap
943 • There is now a JavaScript section.
945 perlunicode
947 • The documentation has been updated to reflect "Bidi_Class" changes
949 in Unicode 6.3.
950 perlvar
952 • A new section explaining the performance issues of $`, $& and $',
954 including workarounds and changes in different versions of Perl,
955 has been added.
956 • Three English variable names which have long been documented but do
958 not actually exist have been removed from the documentation. These
959 were $OLD_PERL_VERSION, $OFMT, and $ARRAY_BASE.
960 (Actually, "OLD_PERL_VERSION" does exist, starting with this
962 revision, but remained undocumented until perl 5.22.0.)
963 perlxs
965 • Several problems in the "MY_CXT" example have been fixed.
967
969 The following additions or changes have been made to diagnostic output,
970 including warnings and fatal error messages. For the complete list of
971 diagnostic messages, see perldiag.
972 New Diagnostics
974 New Errors
975 • delete argument is index/value array slice, use array slice
977 (F) You used index/value array slice syntax (%array[...]) as the
979 argument to "delete". You probably meant @array[...] with an @
980 symbol instead.
981 • delete argument is key/value hash slice, use hash slice
983 (F) You used key/value hash slice syntax (%hash{...}) as the
985 argument to "delete". You probably meant @hash{...} with an @
986 symbol instead.
987 • Magical list constants are not supported
989 (F) You assigned a magical array to a stash element, and then tried
991 to use the subroutine from the same slot. You are asking Perl to
992 do something it cannot do, details subject to change between Perl
993 versions.
994 • Added Setting $/ to a %s reference is forbidden
996 New Warnings
998 • %s on reference is experimental:
1000 The "auto-deref" feature is experimental.
1002 Starting in v5.14.0, it was possible to use push, pop, keys, and
1004 other built-in functions not only on aggregate types, but on
1005 references to them. The feature was not deployed to its original
1006 intended specification, and now may become redundant to postfix
1007 dereferencing. It has always been categorized as an experimental
1008 feature, and in v5.20.0 is carries a warning as such.
1009 Warnings will now be issued at compile time when these operations
1011 are detected.
1012 no if $] >= 5.01908, warnings => "experimental::autoderef";
1014 Consider, though, replacing the use of these features, as they may
1016 change behavior again before becoming stable.
1017 • A sequence of multiple spaces in a charnames alias definition is
1019 deprecated
1020 Trailing white-space in a charnames alias definition is deprecated
1022 These two deprecation warnings involving "\N{...}" were incorrectly
1024 implemented. They did not warn by default (now they do) and could
1025 not be made fatal via "use warnings FATAL => 'deprecated'" (now
1026 they can).
1027 • Attribute prototype(%s) discards earlier prototype attribute in
1029 same sub
1030 (W misc) A sub was declared as "sub foo : prototype(A) :
1032 prototype(B) {}", for example. Since each sub can only have one
1033 prototype, the earlier declaration(s) are discarded while the last
1034 one is applied.
1035 • Invalid \0 character in %s for %s: %s\0%s
1037 (W syscalls) Embedded \0 characters in pathnames or other system
1039 call arguments produce a warning as of 5.20. The parts after the
1040 \0 were formerly ignored by system calls.
1041 • Matched non-Unicode code point 0x%X against Unicode property; may
1043 not be portable.
1044 This replaces the message "Code point 0x%X is not Unicode, all \p{}
1046 matches fail; all \P{} matches succeed".
1047 • Missing ']' in prototype for %s : %s
1049 (W illegalproto) A grouping was started with "[" but never closed
1051 with "]".
1052 • Possible precedence issue with control flow operator
1054 (W syntax) There is a possible problem with the mixing of a control
1056 flow operator (e.g. "return") and a low-precedence operator like
1057 "or". Consider:
1058 sub { return $a or $b; }
1060 This is parsed as:
1062 sub { (return $a) or $b; }
1064 Which is effectively just:
1066 sub { return $a; }
1068 Either use parentheses or the high-precedence variant of the
1070 operator.
1071 Note this may be also triggered for constructs like:
1073 sub { 1 if die; }
1075 • Postfix dereference is experimental
1077 (S experimental::postderef) This warning is emitted if you use the
1079 experimental postfix dereference syntax. Simply suppress the
1080 warning if you want to use the feature, but know that in doing so
1081 you are taking the risk of using an experimental feature which may
1082 change or be removed in a future Perl version:
1083 no warnings "experimental::postderef";
1085 use feature "postderef", "postderef_qq";
1086 $ref->$*;
1087 $aref->@*;
1088 $aref->@[@indices];
1089 ... etc ...
1090 • Prototype '%s' overridden by attribute 'prototype(%s)' in %s
1092 (W prototype) A prototype was declared in both the parentheses
1094 after the sub name and via the prototype attribute. The prototype
1095 in parentheses is useless, since it will be replaced by the
1096 prototype from the attribute before it's ever used.
1097 • Scalar value @%s[%s] better written as $%s[%s]
1099 (W syntax) In scalar context, you've used an array index/value
1101 slice (indicated by %) to select a single element of an array.
1102 Generally it's better to ask for a scalar value (indicated by $).
1103 The difference is that $foo[&bar] always behaves like a scalar,
1104 both in the value it returns and when evaluating its argument,
1105 while %foo[&bar] provides a list context to its subscript, which
1106 can do weird things if you're expecting only one subscript. When
1107 called in list context, it also returns the index (what &bar
1108 returns) in addition to the value.
1109 • Scalar value @%s{%s} better written as $%s{%s}
1111 (W syntax) In scalar context, you've used a hash key/value slice
1113 (indicated by %) to select a single element of a hash. Generally
1114 it's better to ask for a scalar value (indicated by $). The
1115 difference is that $foo{&bar} always behaves like a scalar, both in
1116 the value it returns and when evaluating its argument, while
1117 @foo{&bar} and provides a list context to its subscript, which can
1118 do weird things if you're expecting only one subscript. When
1119 called in list context, it also returns the key in addition to the
1120 value.
1121 • Setting $/ to a reference to %s as a form of slurp is deprecated,
1123 treating as undef
1124 • Unexpected exit %u
1126 (S) exit() was called or the script otherwise finished gracefully
1128 when "PERL_EXIT_WARN" was set in "PL_exit_flags".
1129 • Unexpected exit failure %d
1131 (S) An uncaught die() was called when "PERL_EXIT_WARN" was set in
1133 "PL_exit_flags".
1134 • Use of literal control characters in variable names is deprecated
1136 (D deprecated) Using literal control characters in the source to
1138 refer to the ^FOO variables, like $^X and ${^GLOBAL_PHASE} is now
1139 deprecated. This only affects code like $\cT, where \cT is a
1140 control (like a "SOH") in the source code: ${"\cT"} and $^T remain
1141 valid.
1142 • Useless use of greediness modifier
1144 This fixes [Perl #42957].
1146 Changes to Existing Diagnostics
1148 • Warnings and errors from the regexp engine are now UTF-8 clean.
1149 • The "Unknown switch condition" error message has some slight
1151 changes. This error triggers when there is an unknown condition in
1152 a "(?(foo))" conditional. The error message used to read:
1153 Unknown switch condition (?(%s in regex;
1155 But what %s could be was mostly up to luck. For "(?(foobar))", you
1157 might have seen "fo" or "f". For Unicode characters, you would
1158 generally get a corrupted string. The message has been changed to
1159 read:
1160 Unknown switch condition (?(...)) in regex;
1162 Additionally, the '<-- HERE' marker in the error will now point to
1164 the correct spot in the regex.
1165 • The "%s "\x%X" does not map to Unicode" warning is now correctly
1167 listed as a severe warning rather than as a fatal error.
1168 • Under rare circumstances, one could get a "Can't coerce readonly
1170 REF to string" instead of the customary "Modification of a read-
1171 only value". This alternate error message has been removed.
1172 • "Ambiguous use of * resolved as operator *": This and similar
1174 warnings about "%" and "&" used to occur in some circumstances
1175 where there was no operator of the type cited, so the warning was
1176 completely wrong. This has been fixed [perl #117535, #76910].
1177 • Warnings about malformed subroutine prototypes are now more
1179 consistent in how the prototypes are rendered. Some of these
1180 warnings would truncate prototypes containing nulls. In other
1181 cases one warning would suppress another. The warning about
1182 illegal characters in prototypes no longer says "after '_'" if the
1183 bad character came before the underscore.
1184 • Perl folding rules are not up-to-date for 0x%X; please use the
1186 perlbug utility to report; in regex; marked by <-- HERE in m/%s/
1187 This message is now only in the regexp category, and not in the
1189 deprecated category. It is still a default (i.e., severe) warning
1190 [perl #89648].
1191 • %%s[%s] in scalar context better written as $%s[%s]
1193 This warning now occurs for any %array[$index] or %hash{key} known
1195 to be in scalar context at compile time. Previously it was worded
1196 "Scalar value %%s[%s] better written as $%s[%s]".
1197 • Switch condition not recognized in regex; marked by <-- HERE in
1199 m/%s/:
1200 The description for this diagnostic has been extended to cover all
1202 cases where the warning may occur. Issues with the positioning of
1203 the arrow indicator have also been resolved.
1204 • The error messages for "my($a?$b$c)" and "my(do{})" now mention
1206 "conditional expression" and "do block", respectively, instead of
1207 reading 'Can't declare null operation in "my"'.
1208 • When "use re "debug"" executes a regex containing a backreference,
1210 the debugging output now shows what string is being matched.
1211 • The now fatal error message "Character following "\c" must be
1213 ASCII" has been reworded as "Character following "\c" must be
1214 printable ASCII" to emphasize that in "\cX", X must be a printable
1215 (non-control) ASCII character.
1216
1218 a2p
1219 • A possible crash from an off-by-one error when trying to access
1221 before the beginning of a buffer has been fixed. [perl #120244]
1222 bisect.pl
1224 The git bisection tool Porting/bisect.pl has had many enhancements.
1226 It is provided as part of the source distribution but not installed
1228 because it is not self-contained as it relies on being run from within
1229 a git checkout. Note also that it makes no attempt to fix tests,
1230 correct runtime bugs or make something useful to install - its purpose
1231 is to make minimal changes to get any historical revision of interest
1232 to build and run as close as possible to "as-was", and thereby make
1233 "git bisect" easy to use.
1234 • Can optionally run the test case with a timeout.
1236 • Can now run in-place in a clean git checkout.
1238 • Can run the test case under "valgrind".
1240 • Can apply user supplied patches and fixes to the source checkout
1242 before building.
1243 • Now has fixups to enable building several more historical ranges of
1245 bleadperl, which can be useful for pinpointing the origins of bugs
1246 or behaviour changes.
1247 find2perl
1249 • find2perl now handles "?" wildcards correctly. [perl #113054]
1251 perlbug
1253 • perlbug now has a "-p" option for attaching patches with a bug
1255 report.
1256 • perlbug has been modified to supply the report template with CRLF
1258 line endings on Windows. [GH #13612]
1259 <https://github.com/Perl/perl5/issues/13612>
1260 • perlbug now makes as few assumptions as possible about the encoding
1262 of the report. This will likely change in the future to assume
1263 UTF-8 by default but allow a user override.
1264
1266 • The Makefile.PL for SDBM_File now generates a better Makefile,
1267 which avoids a race condition during parallel makes, which could
1268 cause the build to fail. This is the last known parallel make
1269 problem (on *nix platforms), and therefore we believe that a
1270 parallel make should now always be error free.
1271 • installperl and installman's option handling has been refactored to
1273 use Getopt::Long. Both are used by the Makefile "install" targets,
1274 and are not installed, so these changes are only likely to affect
1275 custom installation scripts.
1276 • Single letter options now also have long names.
1278 • Invalid options are now rejected.
1280 • Command line arguments that are not options are now rejected.
1282 • Each now has a "--help" option to display the usage message.
1284 The behaviour for all valid documented invocations is unchanged.
1286 • Where possible, the build now avoids recursive invocations of make
1288 when building pure-Perl extensions, without removing any
1289 parallelism from the build. Currently around 80 extensions can be
1290 processed directly by the make_ext.pl tool, meaning that 80
1291 invocations of make and 160 invocations of miniperl are no longer
1292 made.
1293 • The build system now works correctly when compiling under GCC or
1295 Clang with link-time optimization enabled (the "-flto" option).
1296 [perl #113022]
1297 • Distinct library basenames with "d_libname_unique".
1299 When compiling perl with this option, the library files for XS
1301 modules are named something "unique" -- for example,
1302 Hash/Util/Util.so becomes Hash/Util/PL_Hash__Util.so. This
1303 behavior is similar to what currently happens on VMS, and serves as
1304 groundwork for the Android port.
1305 • "sysroot" option to indicate the logical root directory under gcc
1307 and clang.
1308 When building with this option set, both Configure and the
1310 compilers search for all headers and libraries under this new
1311 sysroot, instead of /.
1312 This is a huge time saver if cross-compiling, but can also help on
1314 native builds if your toolchain's files have non-standard
1315 locations.
1316 • The cross-compilation model has been renovated. There's several
1318 new options, and some backwards-incompatible changes:
1319 We now build binaries for miniperl and generate_uudmap to be used
1321 on the host, rather than running every miniperl call on the target;
1322 this means that, short of 'make test', we no longer need access to
1323 the target system once Configure is done. You can provide already-
1324 built binaries through the "hostperl" and "hostgenerate" options to
1325 Configure.
1326 Additionally, if targeting an EBCDIC platform from an ASCII host,
1328 or viceversa, you'll need to run Configure with "-Uhostgenerate",
1329 to indicate that generate_uudmap should be run on the target.
1330 Finally, there's also a way of having Configure end early, right
1332 after building the host binaries, by cross-compiling without
1333 specifying a "targethost".
1334 The incompatible changes include no longer using xconfig.h, xlib,
1336 or Cross.pm, so canned config files and Makefiles will have to be
1337 updated.
1338 • Related to the above, there is now a way of specifying the location
1340 of sh (or equivalent) on the target system: "targetsh".
1341 For example, Android has its sh in /system/bin/sh, so if cross-
1343 compiling from a more normal Unixy system with sh in /bin/sh,
1344 "targetsh" would end up as /system/bin/sh, and "sh" as /bin/sh.
1345 • By default, gcc 4.9 does some optimizations that break perl. The
1347 -fwrapv option disables those optimizations (and probably others),
1348 so for gcc 4.3 and later (since the there might be similar problems
1349 lurking on older versions too, but -fwrapv was broken before 4.3,
1350 and the optimizations probably won't go away), Configure now adds
1351 -fwrapv unless the user requests -fno-wrapv, which disables
1352 -fwrapv, or -fsanitize=undefined, which turns the overflows -fwrapv
1353 ignores into runtime errors. [GH #13690]
1354 <https://github.com/Perl/perl5/issues/13690>
1355
1357 • The "test.valgrind" make target now allows tests to be run in
1358 parallel. This target allows Perl's test suite to be run under
1359 Valgrind, which detects certain sorts of C programming errors,
1360 though at significant cost in running time. On suitable hardware,
1361 allowing parallel execution claws back a lot of that additional
1362 cost. [perl #121431]
1363 • Various tests in t/porting/ are no longer skipped when the perl
1365 .git directory is outside the perl tree and pointed to by $GIT_DIR.
1366 [perl #120505]
1367 • The test suite no longer fails when the user's interactive shell
1369 maintains a $PWD environment variable, but the /bin/sh used for
1370 running tests doesn't.
1371
1373 New Platforms
1374 Android
1375 Perl can now be built for Android, either natively or through
1376 cross-compilation, for all three currently available architectures
1377 (ARM, MIPS, and x86), on a wide range of versions.
1378 Bitrig
1380 Compile support has been added for Bitrig, a fork of OpenBSD.
1381 FreeMiNT
1383 Support has been added for FreeMiNT, a free open-source OS for the
1384 Atari ST system and its successors, based on the original MiNT that
1385 was officially adopted by Atari.
1386 Synology
1388 Synology ships its NAS boxes with a lean Linux distribution (DSM)
1389 on relative cheap CPU's (like the Marvell Kirkwood mv6282 -
1390 ARMv5tel or Freescale QorIQ P1022 ppc - e500v2) not meant for
1391 workstations or development. These boxes should build now. The
1392 basic problems are the non-standard location for tools.
1393 Discontinued Platforms
1395 "sfio"
1396 Code related to supporting the "sfio" I/O system has been removed.
1397 Perl 5.004 added support to use the native API of "sfio", AT&T's
1399 Safe/Fast I/O library. This code still built with v5.8.0, albeit
1400 with many regression tests failing, but was inadvertently broken
1401 before the v5.8.1 release, meaning that it has not worked on any
1402 version of Perl released since then. In over a decade we have
1403 received no bug reports about this, hence it is clear that no-one
1404 is using this functionality on any version of Perl that is still
1405 supported to any degree.
1406 AT&T 3b1
1408 Configure support for the 3b1, also known as the AT&T Unix PC (and
1409 the similar AT&T 7300), has been removed.
1410 DG/UX
1412 DG/UX was a Unix sold by Data General. The last release was in
1413 April 2001. It only runs on Data General's own hardware.
1414 EBCDIC
1416 In the absence of a regular source of smoke reports, code intended
1417 to support native EBCDIC platforms will be removed from perl before
1418 5.22.0.
1419 Platform-Specific Notes
1421 Cygwin
1422 • recv() on a connected handle would populate the returned sender
1423 address with whatever happened to be in the working buffer.
1424 recv() now uses a workaround similar to the Win32 recv()
1425 wrapper and returns an empty string when recvfrom(2) doesn't
1426 modify the supplied address length. [perl #118843]
1427 • Fixed a build error in cygwin.c on Cygwin 1.7.28.
1429 Tests now handle the errors that occur when "cygserver" isn't
1431 running.
1432 GNU/Hurd
1434 The BSD compatibility library "libbsd" is no longer required for
1435 builds.
1436 Linux
1438 The hints file now looks for "libgdbm_compat" only if "libgdbm"
1439 itself is also wanted. The former is never useful without the
1440 latter, and in some circumstances, including it could actually
1441 prevent building.
1442 Mac OS
1444 The build system now honors an "ld" setting supplied by the user
1445 running Configure.
1446 MidnightBSD
1448 "objformat" was removed from version 0.4-RELEASE of MidnightBSD and
1449 had been deprecated on earlier versions. This caused the build
1450 environment to be erroneously configured for "a.out" rather than
1451 "elf". This has been now been corrected.
1452 Mixed-endian platforms
1454 The code supporting "pack" and "unpack" operations on mixed endian
1455 platforms has been removed. We believe that Perl has long been
1456 unable to build on mixed endian architectures (such as PDP-11s), so
1457 we don't think that this change will affect any platforms which
1458 were able to build v5.18.0.
1459 VMS
1461 • The "PERL_ENV_TABLES" feature to control the population of %ENV
1462 at perl start-up was broken in Perl 5.16.0 but has now been
1463 fixed.
1464 • Skip access checks on remotes in opendir(). [perl #121002]
1466 • A check for glob metacharacters in a path returned by the
1468 "glob()" operator has been replaced with a check for VMS
1469 wildcard characters. This saves a significant number of
1470 unnecessary "lstat()" calls such that some simple glob
1471 operations become 60-80% faster.
1472 Win32
1474 • "rename" and "link" on Win32 now set $! to ENOSPC and EDQUOT
1475 when appropriate. [perl #119857]
1476 • The BUILD_STATIC and ALL_STATIC makefile options for linking
1478 some or (nearly) all extensions statically (into perl520.dll,
1479 and into a separate perl-static.exe too) were broken for MinGW
1480 builds. This has now been fixed.
1481 The ALL_STATIC option has also been improved to include the
1483 Encode and Win32 extensions (for both VC++ and MinGW builds).
1484 • Support for building with Visual C++ 2013 has been added.
1486 There are currently two possible test failures (see "Testing
1487 Perl on Windows" in perlwin32) which will hopefully be resolved
1488 soon.
1489 • Experimental support for building with Intel C++ Compiler has
1491 been added. The nmake makefile (win32/Makefile) and the dmake
1492 makefile (win32/makefile.mk) can be used. A "nmake test" will
1493 not pass at this time due to cpan/CGI/t/url.t.
1494 • Killing a process tree with "kill" in perlfunc and a negative
1496 signal, was broken starting in 5.18.0. In this bug, "kill"
1497 always returned 0 for a negative signal even for valid PIDs,
1498 and no processes were terminated. This has been fixed [perl
1499 #121230].
1500 • The time taken to build perl on Windows has been reduced quite
1502 significantly (time savings in the region of 30-40% are
1503 typically seen) by reducing the number of, usually failing, I/O
1504 calls for each "require()" (for miniperl.exe only). [GH
1505 #13566] <https://github.com/Perl/perl5/issues/13566>
1506 • About 15 minutes of idle sleeping was removed from running
1508 "make test" due to a bug in which the timeout monitor used for
1509 tests could not be cancelled once the test completes, and the
1510 full timeout period elapsed before running the next test file.
1511 [GH #13647] <https://github.com/Perl/perl5/issues/13647>
1512 • On a perl built without pseudo-fork (pseudo-fork builds were
1514 not affected by this bug), killing a process tree with "kill()"
1515 and a negative signal resulted in "kill()" inverting the
1516 returned value. For example, if "kill()" killed 1 process tree
1517 PID then it returned 0 instead of 1, and if "kill()" was passed
1518 2 invalid PIDs then it returned 2 instead of 0. This has
1519 probably been the case since the process tree kill feature was
1520 implemented on Win32. It has now been corrected to follow the
1521 documented behaviour. [GH #13595]
1522 <https://github.com/Perl/perl5/issues/13595>
1523 • When building a 64-bit perl, an uninitialized memory read in
1525 miniperl.exe, used during the build process, could lead to a
1526 4GB wperl.exe being created. This has now been fixed. (Note
1527 that perl.exe itself was unaffected, but obviously wperl.exe
1528 would have been completely broken.) [GH #13677]
1529 <https://github.com/Perl/perl5/issues/13677>
1530 • Perl can now be built with gcc version 4.8.1 from
1532 <http://www.mingw.org>. This was previously broken due to an
1533 incorrect definition of DllMain() in one of perl's source
1534 files. Earlier gcc versions were also affected when using
1535 version 4 of the w32api package. Versions of gcc available
1536 from <http://mingw-w64.sourceforge.net/> were not affected.
1537 [GH #13733] <https://github.com/Perl/perl5/issues/13733>
1538 • The test harness now has no failures when perl is built on a
1540 FAT drive with the Windows OS on an NTFS drive. [GH #6348]
1541 <https://github.com/Perl/perl5/issues/6348>
1542 • When cloning the context stack in fork() emulation,
1544 Perl_cx_dup() would crash accessing parameter information for
1545 context stack entries that included no parameters, as with
1546 "&foo;". [GH #13763]
1547 <https://github.com/Perl/perl5/issues/13763>
1548 • Introduced by [GH #12161]
1550 <https://github.com/Perl/perl5/issues/12161>, a memory leak on
1551 every call to "system" and backticks (" `` "), on most Win32
1552 Perls starting from 5.18.0 has been fixed. The memory leak
1553 only occurred if you enabled pseudo-fork in your build of Win32
1554 Perl, and were running that build on Server 2003 R2 or newer
1555 OS. The leak does not appear on WinXP SP3. [GH #13741]
1556 <https://github.com/Perl/perl5/issues/13741>
1557 WinCE
1559 • The building of XS modules has largely been restored. Several
1560 still cannot (yet) be built but it is now possible to build
1561 Perl on WinCE with only a couple of further patches (to Socket
1562 and ExtUtils::MakeMaker), hopefully to be incorporated soon.
1563 • Perl can now be built in one shot with no user intervention on
1565 WinCE by running "nmake -f Makefile.ce all".
1566 Support for building with EVC (Embedded Visual C++) 4 has been
1568 restored. Perl can also be built using Smart Devices for
1569 Visual C++ 2005 or 2008.
1570
1572 • The internal representation has changed for the match variables $1,
1573 $2 etc., $`, $&, $', ${^PREMATCH}, ${^MATCH} and ${^POSTMATCH}. It
1574 uses slightly less memory, avoids string comparisons and numeric
1575 conversions during lookup, and uses 23 fewer lines of C. This
1576 change should not affect any external code.
1577 • Arrays now use NULL internally to represent unused slots, instead
1579 of &PL_sv_undef. &PL_sv_undef is no longer treated as a special
1580 value, so av_store(av, 0, &PL_sv_undef) will cause element 0 of
1581 that array to hold a read-only undefined scalar. "$array[0] =
1582 anything" will croak and "\$array[0]" will compare equal to
1583 "\undef".
1584 • The SV returned by HeSVKEY_force() now correctly reflects the
1586 UTF8ness of the underlying hash key when that key is not stored as
1587 a SV. [perl #79074]
1588 • Certain rarely used functions and macros available to XS code are
1590 now deprecated. These are: "utf8_to_uvuni_buf" (use
1591 "utf8_to_uvchr_buf" instead), "valid_utf8_to_uvuni" (use
1592 "utf8_to_uvchr_buf" instead), "NATIVE_TO_NEED" (this did not work
1593 properly anyway), and "ASCII_TO_NEED" (this did not work properly
1594 anyway).
1595 Starting in this release, almost never does application code need
1597 to distinguish between the platform's character set and Latin1, on
1598 which the lowest 256 characters of Unicode are based. New code
1599 should not use "utf8n_to_uvuni" (use "utf8_to_uvchr_buf" instead),
1600 nor "uvuni_to_utf8" (use "uvchr_to_utf8" instead),
1601 • The Makefile shortcut targets for many rarely (or never) used
1603 testing and profiling targets have been removed, or merged into the
1604 only other Makefile target that uses them. Specifically, these
1605 targets are gone, along with documentation that referenced them or
1606 explained how to use them:
1607 check.third check.utf16 check.utf8 coretest minitest.prep
1609 minitest.utf16 perl.config.dashg perl.config.dashpg
1610 perl.config.gcov perl.gcov perl.gprof perl.gprof.config
1611 perl.pixie perl.pixie.atom perl.pixie.config perl.pixie.irix
1612 perl.third perl.third.config perl.valgrind.config purecovperl
1613 pureperl quantperl test.deparse test.taintwarn test.third
1614 test.torture test.utf16 test.utf8 test_notty.deparse
1615 test_notty.third test_notty.valgrind test_prep.third
1616 test_prep.valgrind torturetest ucheck ucheck.third ucheck.utf16
1617 ucheck.valgrind utest utest.third utest.utf16 utest.valgrind
1618 It's still possible to run the relevant commands by "hand" - no
1620 underlying functionality has been removed.
1621 • It is now possible to keep Perl from initializing locale handling.
1623 For the most part, Perl doesn't pay attention to locale. (See
1624 perllocale.) Nonetheless, until now, on startup, it has always
1625 initialized locale handling to the system default, just in case the
1626 program being executed ends up using locales. (This is one of the
1627 first things a locale-aware program should do, long before Perl
1628 knows if it will actually be needed or not.) This works well
1629 except when Perl is embedded in another application which wants a
1630 locale that isn't the system default. Now, if the environment
1631 variable "PERL_SKIP_LOCALE_INIT" is set at the time Perl is
1632 started, this initialization step is skipped. Prior to this, on
1633 Windows platforms, the only workaround for this deficiency was to
1634 use a hacked-up copy of internal Perl code. Applications that need
1635 to use older Perls can discover if the embedded Perl they are using
1636 needs the workaround by testing that the C preprocessor symbol
1637 "HAS_SKIP_LOCALE_INIT" is not defined. [RT #38193]
1638 • "BmRARE" and "BmPREVIOUS" have been removed. They were not used
1640 anywhere and are not part of the API. For XS modules, they are now
1641 #defined as 0.
1642 • "sv_force_normal", which usually croaks on read-only values, used
1644 to allow read-only values to be modified at compile time. This has
1645 been changed to croak on read-only values regardless. This change
1646 uncovered several core bugs.
1647 • Perl's new copy-on-write mechanism (which is now enabled by
1649 default), allows any "SvPOK" scalar to be automatically upgraded to
1650 a copy-on-write scalar when copied. A reference count on the string
1651 buffer is stored in the string buffer itself.
1652 For example:
1654 $ perl -MDevel::Peek -e'$a="abc"; $b = $a; Dump $a; Dump $b'
1656 SV = PV(0x260cd80) at 0x2620ad8
1657 REFCNT = 1
1658 FLAGS = (POK,IsCOW,pPOK)
1659 PV = 0x2619bc0 "abc"\0
1660 CUR = 3
1661 LEN = 16
1662 COW_REFCNT = 1
1663 SV = PV(0x260ce30) at 0x2620b20
1664 REFCNT = 1
1665 FLAGS = (POK,IsCOW,pPOK)
1666 PV = 0x2619bc0 "abc"\0
1667 CUR = 3
1668 LEN = 16
1669 COW_REFCNT = 1
1670 Note that both scalars share the same PV buffer and have a
1672 COW_REFCNT greater than zero.
1673 This means that XS code which wishes to modify the "SvPVX()" buffer
1675 of an SV should call "SvPV_force()" or similar first, to ensure a
1676 valid (and unshared) buffer, and to call "SvSETMAGIC()" afterwards.
1677 This in fact has always been the case (for example hash keys were
1678 already copy-on-write); this change just spreads the COW behaviour
1679 to a wider variety of SVs.
1680 One important difference is that before 5.18.0, shared hash-key
1682 scalars used to have the "SvREADONLY" flag set; this is no longer
1683 the case.
1684 This new behaviour can still be disabled by running Configure with
1686 -Accflags=-DPERL_NO_COW. This option will probably be removed in
1687 Perl 5.22.
1688 • "PL_sawampersand" is now a constant. The switch this variable
1690 provided (to enable/disable the pre-match copy depending on whether
1691 $& had been seen) has been removed and replaced with copy-on-write,
1692 eliminating a few bugs.
1693 The previous behaviour can still be enabled by running Configure
1695 with -Accflags=-DPERL_SAWAMPERSAND.
1696 • The functions "my_swap", "my_htonl" and "my_ntohl" have been
1698 removed. It is unclear why these functions were ever marked as A,
1699 part of the API. XS code can't call them directly, as it can't rely
1700 on them being compiled. Unsurprisingly, no code on CPAN references
1701 them.
1702 • The signature of the "Perl_re_intuit_start()" regex function has
1704 changed; the function pointer "intuit" in the regex engine plugin
1705 structure has also changed accordingly. A new parameter, "strbeg"
1706 has been added; this has the same meaning as the same-named
1707 parameter in "Perl_regexec_flags". Previously intuit would try to
1708 guess the start of the string from the passed SV (if any), and
1709 would sometimes get it wrong (e.g. with an overloaded SV).
1710 • The signature of the "Perl_regexec_flags()" regex function has
1712 changed; the function pointer "exec" in the regex engine plugin
1713 structure has also changed to match. The "minend" parameter now
1714 has type "SSize_t" to better support 64-bit systems.
1715 • XS code may use various macros to change the case of a character or
1717 code point (for example "toLOWER_utf8()"). Only a couple of these
1718 were documented until now; and now they should be used in
1719 preference to calling the underlying functions. See "Character
1720 case changing" in perlapi.
1721 • The code dealt rather inconsistently with uids and gids. Some
1723 places assumed that they could be safely stored in UVs, others in
1724 IVs, others in ints. Four new macros are introduced: SvUID(),
1725 sv_setuid(), SvGID(), and sv_setgid()
1726 • "sv_pos_b2u_flags" has been added to the API. It is similar to
1728 "sv_pos_b2u", but supports long strings on 64-bit platforms.
1729 • "PL_exit_flags" can now be used by perl embedders or other XS code
1731 to have perl "warn" or "abort" on an attempted exit. [perl #52000]
1732 • Compiling with "-Accflags=-PERL_BOOL_AS_CHAR" now allows C99 and
1734 C++ compilers to emulate the aliasing of "bool" to "char" that perl
1735 does for C89 compilers. [perl #120314]
1736 • The "sv" argument in "sv_2pv_flags" in perlapi, "sv_2iv_flags" in
1738 perlapi, "sv_2uv_flags" in perlapi, and "sv_2nv_flags" in perlapi
1739 and their older wrappers sv_2pv, sv_2iv, sv_2uv, sv_2nv, is now
1740 non-NULL. Passing NULL now will crash. When the non-NULL marker
1741 was introduced en masse in 5.9.3 the functions were marked non-
1742 NULL, but since the creation of the SV API in 5.0 alpha 2, if NULL
1743 was passed, the functions returned 0 or false-type values. The code
1744 that supports "sv" argument being non-NULL dates to 5.0 alpha 2
1745 directly, and indirectly to Perl 1.0 (pre 5.0 api). The lack of
1746 documentation that the functions accepted a NULL "sv" was corrected
1747 in 5.11.0 and between 5.11.0 and 5.19.5 the functions were marked
1748 NULLOK. As an optimization the NULLOK code has now been removed,
1749 and the functions became non-NULL marked again, because core
1750 getter-type macros never pass NULL to these functions and would
1751 crash before ever passing NULL.
1752 The only way a NULL "sv" can be passed to sv_2*v* functions is if
1754 XS code directly calls sv_2*v*. This is unlikely as XS code uses
1755 Sv*V* macros to get the underlying value out of the SV. One
1756 possible situation which leads to a NULL "sv" being passed to
1757 sv_2*v* functions, is if XS code defines its own getter type Sv*V*
1758 macros, which check for NULL before dereferencing and checking the
1759 SV's flags through public API Sv*OK* macros or directly using
1760 private API "SvFLAGS", and if "sv" is NULL, then calling the sv_2*v
1761 functions with a NULL literal or passing the "sv" containing a NULL
1762 value.
1763 • newATTRSUB is now a macro
1765 The public API newATTRSUB was previously a macro to the private
1767 function Perl_newATTRSUB. Function Perl_newATTRSUB has been
1768 removed. newATTRSUB is now macro to a different internal function.
1769 • Changes in warnings raised by "utf8n_to_uvchr()"
1771 This bottom level function decodes the first character of a UTF-8
1773 string into a code point. It is accessible to "XS" level code, but
1774 it's discouraged from using it directly. There are higher level
1775 functions that call this that should be used instead, such as
1776 "utf8_to_uvchr_buf" in perlapi. For completeness though, this
1777 documents some changes to it. Now, tests for malformations are
1778 done before any tests for other potential issues. One of those
1779 issues involves code points so large that they have never appeared
1780 in any official standard (the current standard has scaled back the
1781 highest acceptable code point from earlier versions). It is
1782 possible (though not done in CPAN) to warn and/or forbid these code
1783 points, while accepting smaller code points that are still above
1784 the legal Unicode maximum. The warning message for this now
1785 includes the code point if representable on the machine.
1786 Previously it always displayed raw bytes, which is what it still
1787 does for non-representable code points.
1788 • Regexp engine changes that affect the pluggable regex engine
1790 interface
1791 Many flags that used to be exposed via regexp.h and used to
1793 populate the extflags member of struct regexp have been removed.
1794 These fields were technically private to Perl's own regexp engine
1795 and should not have been exposed there in the first place.
1796 The affected flags are:
1798 RXf_NOSCAN
1800 RXf_CANY_SEEN
1801 RXf_GPOS_SEEN
1802 RXf_GPOS_FLOAT
1803 RXf_ANCH_BOL
1804 RXf_ANCH_MBOL
1805 RXf_ANCH_SBOL
1806 RXf_ANCH_GPOS
1807 As well as the follow flag masks:
1809 RXf_ANCH_SINGLE
1811 RXf_ANCH
1812 All have been renamed to PREGf_ equivalents and moved to regcomp.h.
1814 The behavior previously achieved by setting one or more of the
1816 RXf_ANCH_ flags (via the RXf_ANCH mask) have now been replaced by a
1817 *single* flag bit in extflags:
1818 RXf_IS_ANCHORED
1820 pluggable regex engines which previously used to set these flags
1822 should now set this flag ALONE.
1823 • The Perl core now consistently uses "av_tindex()" ("the top index
1825 of an array") as a more clearly-named synonym for "av_len()".
1826 • The obscure interpreter variable "PL_timesbuf" is expected to be
1828 removed early in the 5.21.x development series, so that Perl 5.22.0
1829 will not provide it to XS authors. While the variable still exists
1830 in 5.20.0, we hope that this advance warning of the deprecation
1831 will help anyone who is using that variable.
1832
1834 Regular Expressions
1835 • Fixed a small number of regexp constructions that could either fail
1836 to match or crash perl when the string being matched against was
1837 allocated above the 2GB line on 32-bit systems. [RT #118175]
1838 • Various memory leaks involving the parsing of the "(?[...])"
1840 regular expression construct have been fixed.
1841 • "(?[...])" now allows interpolation of precompiled patterns
1843 consisting of "(?[...])" with bracketed character classes inside
1844 ("$pat = qr/(?[ [a] ])/; /(?[ $pat ])/"). Formerly, the brackets
1845 would confuse the regular expression parser.
1846 • The "Quantifier unexpected on zero-length expression" warning
1848 message could appear twice starting in Perl v5.10 for a regular
1849 expression also containing alternations (e.g., "a|b") triggering
1850 the trie optimisation.
1851 • Perl v5.18 inadvertently introduced a bug whereby interpolating
1853 mixed up- and down-graded UTF-8 strings in a regex could result in
1854 malformed UTF-8 in the pattern: specifically if a downgraded
1855 character in the range "\x80..\xff" followed a UTF-8 string, e.g.
1856 utf8::upgrade( my $u = "\x{e5}");
1858 utf8::downgrade(my $d = "\x{e5}");
1859 /$u$d/
1860 [RT #118297]
1862 • In regular expressions containing multiple code blocks, the values
1864 of $1, $2, etc., set by nested regular expression calls would leak
1865 from one block to the next. Now these variables always refer to
1866 the outer regular expression at the start of an embedded block
1867 [perl #117917].
1868 • "/$qr/p" was broken in Perl 5.18.0; the "/p" flag was ignored.
1870 This has been fixed. [perl #118213]
1871 • Starting in Perl 5.18.0, a construct like "/[#](?{})/x" would have
1873 its "#" incorrectly interpreted as a comment. The code block would
1874 be skipped, unparsed. This has been corrected.
1875 • Starting in Perl 5.001, a regular expression like "/[#$a]/x" or
1877 "/[#]$a/x" would have its "#" incorrectly interpreted as a comment,
1878 so the variable would not interpolate. This has been corrected.
1879 [perl #45667]
1880 • Perl 5.18.0 inadvertently made dereferenced regular expressions
1882 ("${ qr// }") false as booleans. This has been fixed.
1883 • The use of "\G" in regular expressions, where it's not at the start
1885 of the pattern, is now slightly less buggy (although it is still
1886 somewhat problematic).
1887 • Where a regular expression included code blocks ("/(?{...})/"), and
1889 where the use of constant overloading triggered a re-compilation of
1890 the code block, the second compilation didn't see its outer lexical
1891 scope. This was a regression in Perl 5.18.0.
1892 • The string position set by "pos" could shift if the string changed
1894 representation internally to or from utf8. This could happen,
1895 e.g., with references to objects with string overloading.
1896 • Taking references to the return values of two "pos" calls with the
1898 same argument, and then assigning a reference to one and "undef" to
1899 the other, could result in assertion failures or memory leaks.
1900 • Elements of @- and @+ now update correctly when they refer to non-
1902 existent captures. Previously, a referenced element ("$ref =
1903 \$-[1]") could refer to the wrong match after subsequent matches.
1904 • The code that parses regex backrefs (or ambiguous backref/octals)
1906 such as \123 did a simple atoi(), which could wrap round to
1907 negative values on long digit strings and cause segmentation
1908 faults. This has now been fixed. [perl #119505]
1909 • Assigning another typeglob to "*^R" no longer makes the regular
1911 expression engine crash.
1912 • The "\N" regular expression escape, when used without the curly
1914 braces (to mean "[^\n]"), was ignoring a following "*" if followed
1915 by whitespace under /x. It had been this way since "\N" to mean
1916 "[^\n]" was introduced in 5.12.0.
1917 • "s///", "tr///" and "y///" now work when a wide character is used
1919 as the delimiter. [perl #120463]
1920 • Some cases of unterminated (?...) sequences in regular expressions
1922 (e.g., "/(?</") have been fixed to produce the proper error message
1923 instead of "panic: memory wrap". Other cases (e.g., "/(?(/") have
1924 yet to be fixed.
1925 • When a reference to a reference to an overloaded object was
1927 returned from a regular expression "(??{...})" code block, an
1928 incorrect implicit dereference could take place if the inner
1929 reference had been returned by a code block previously.
1930 • A tied variable returned from "(??{...})" sees the inner values of
1932 match variables (i.e., the $1 etc. from any matches inside the
1933 block) in its FETCH method. This was not the case if a reference
1934 to an overloaded object was the last thing assigned to the tied
1935 variable. Instead, the match variables referred to the outer
1936 pattern during the FETCH call.
1937 • Fix unexpected tainting via regexp using locale. Previously, under
1939 certain conditions, the use of character classes could cause
1940 tainting when it shouldn't. Some character classes are locale-
1941 dependent, but before this patch, sometimes tainting was happening
1942 even for character classes that don't depend on the locale. [perl
1943 #120675]
1944 • Under certain conditions, Perl would throw an error if in a
1946 lookbehind assertion in a regexp, the assertion referred to a named
1947 subpattern, complaining the lookbehind was variable when it wasn't.
1948 This has been fixed. [perl #120600], [perl #120618]. The current
1949 fix may be improved on in the future.
1950 • $^R wasn't available outside of the regular expression that
1952 initialized it. [perl #121070]
1953 • A large set of fixes and refactoring for re_intuit_start() was
1955 merged, the highlights are:
1956 • Fixed a panic when compiling the regular expression
1958 "/\x{100}[xy]\x{100}{2}/".
1959 • Fixed a performance regression when performing a global pattern
1961 match against a UTF-8 string. [perl #120692]
1962 • Fixed another performance issue where matching a regular
1964 expression like "/ab.{1,2}x/" against a long UTF-8 string would
1965 unnecessarily calculate byte offsets for a large portion of the
1966 string. [perl #120692]
1967 • Fixed an alignment error when compiling regular expressions when
1969 built with GCC on HP-UX 64-bit.
1970 • On 64-bit platforms "pos" can now be set to a value higher than
1972 2**31-1. [perl #72766]
1973 Perl 5 Debugger and -d
1975 • The debugger's "man" command been fixed. It was broken in the
1976 v5.18.0 release. The "man" command is aliased to the names "doc"
1977 and "perldoc" - all now work again.
1978 • @_ is now correctly visible in the debugger, fixing a regression
1980 introduced in v5.18.0's debugger. [RT #118169]
1981 • Under copy-on-write builds (the default as of 5.20.0)
1983 "${'_<-e'}[0]" no longer gets mangled. This is the first line of
1984 input saved for the debugger's use for one-liners [perl #118627].
1985 • On non-threaded builds, setting "${"_<filename"}" to a reference or
1987 typeglob no longer causes "__FILE__" and some error messages to
1988 produce a corrupt string, and no longer prevents "#line" directives
1989 in string evals from providing the source lines to the debugger.
1990 Threaded builds were unaffected.
1991 • Starting with Perl 5.12, line numbers were off by one if the -d
1993 switch was used on the #! line. Now they are correct.
1994 • "*DB::DB = sub {} if 0" no longer stops Perl's debugging mode from
1996 finding "DB::DB" subs declared thereafter.
1997 • "%{'_<...'}" hashes now set breakpoints on the corresponding
1999 "@{'_<...'}" rather than whichever array @DB::dbline is aliased to.
2000 [perl #119799]
2001 • Call set-magic when setting $DB::sub. [perl #121255]
2003 • The debugger's "n" command now respects lvalue subroutines and
2005 steps over them [perl #118839].
2006 Lexical Subroutines
2008 • Lexical constants ("my sub a() { 42 }") no longer crash when
2009 inlined.
2010 • Parameter prototypes attached to lexical subroutines are now
2012 respected when compiling sub calls without parentheses.
2013 Previously, the prototypes were honoured only for calls with
2014 parentheses. [RT #116735]
2015 • Syntax errors in lexical subroutines in combination with calls to
2017 the same subroutines no longer cause crashes at compile time.
2018 • Deep recursion warnings no longer crash lexical subroutines. [RT
2020 #118521]
2021 • The dtrace sub-entry probe now works with lexical subs, instead of
2023 crashing [perl #118305].
2024 • Undefining an inlinable lexical subroutine ("my sub foo() { 42 }
2026 undef &foo") would result in a crash if warnings were turned on.
2027 • An undefined lexical sub used as an inherited method no longer
2029 crashes.
2030 • The presence of a lexical sub named "CORE" no longer stops the
2032 CORE:: prefix from working.
2033 Everything Else
2035 • The OP allocation code now returns correctly aligned memory in all
2036 cases for "struct pmop". Previously it could return memory only
2037 aligned to a 4-byte boundary, which is not correct for an ithreads
2038 build with 64 bit IVs on some 32 bit platforms. Notably, this
2039 caused the build to fail completely on sparc GNU/Linux. [RT
2040 #118055]
2041 • Evaluating large hashes in scalar context is now much faster, as
2043 the number of used chains in the hash is now cached for larger
2044 hashes. Smaller hashes continue not to store it and calculate it
2045 when needed, as this saves one IV. That would be 1 IV overhead for
2046 every object built from a hash. [RT #114576]
2047 • Perl v5.16 inadvertently introduced a bug whereby calls to XSUBs
2049 that were not visible at compile time were treated as lvalues and
2050 could be assigned to, even when the subroutine was not an lvalue
2051 sub. This has been fixed. [RT #117947]
2052 • In Perl v5.18.0 dualvars that had an empty string for the string
2054 part but a non-zero number for the number part starting being
2055 treated as true. In previous versions they were treated as false,
2056 the string representation taking precedence. The old behaviour has
2057 been restored. [RT #118159]
2058 • Since Perl v5.12, inlining of constants that override built-in
2060 keywords of the same name had countermanded "use subs", causing
2061 subsequent mentions of the constant to use the built-in keyword
2062 instead. This has been fixed.
2063 • The warning produced by "-l $handle" now applies to IO refs and
2065 globs, not just to glob refs. That warning is also now UTF8-clean.
2066 [RT #117595]
2067 • "delete local $ENV{nonexistent_env_var}" no longer leaks memory.
2069 • "sort" and "require" followed by a keyword prefixed with "CORE::"
2071 now treat it as a keyword, and not as a subroutine or module name.
2072 [RT #24482]
2073 • Through certain conundrums, it is possible to cause the current
2075 package to be freed. Certain operators ("bless", "reset", "open",
2076 "eval") could not cope and would crash. They have been made more
2077 resilient. [RT #117941]
2078 • Aliasing filehandles through glob-to-glob assignment would not
2080 update internal method caches properly if a package of the same
2081 name as the filehandle existed, resulting in filehandle method
2082 calls going to the package instead. This has been fixed.
2083 • "./Configure -de -Dusevendorprefix" didn't default. [RT #64126]
2085 • The "Statement unlikely to be reached" warning was listed in
2087 perldiag as an "exec"-category warning, but was enabled and
2088 disabled by the "syntax" category. On the other hand, the "exec"
2089 category controlled its fatal-ness. It is now entirely handled by
2090 the "exec" category.
2091 • The "Replacement list is longer that search list" warning for
2093 "tr///" and "y///" no longer occurs in the presence of the "/c"
2094 flag. [RT #118047]
2095 • Stringification of NVs are not cached so that the lexical locale
2097 controls stringification of the decimal point. [perl #108378] [perl
2098 #115800]
2099 • There have been several fixes related to Perl's handling of
2101 locales. perl #38193 was described above in "Internal Changes".
2102 Also fixed is #118197, where the radix (decimal point) character
2103 had to be an ASCII character (which doesn't work for some non-
2104 Western languages); and #115808, in which "POSIX::setlocale()" on
2105 failure returned an "undef" which didn't warn about not being
2106 defined even if those warnings were enabled.
2107 • Compiling a "split" operator whose third argument is a named
2109 constant evaluating to 0 no longer causes the constant's value to
2110 change.
2111 • A named constant used as the second argument to "index" no longer
2113 gets coerced to a string if it is a reference, regular expression,
2114 dualvar, etc.
2115 • A named constant evaluating to the undefined value used as the
2117 second argument to "index" no longer produces "uninitialized"
2118 warnings at compile time. It will still produce them at run time.
2119 • When a scalar was returned from a subroutine in @INC, the
2121 referenced scalar was magically converted into an IO thingy,
2122 possibly resulting in "Bizarre copy" errors if that scalar
2123 continued to be used elsewhere. Now Perl uses an internal copy of
2124 the scalar instead.
2125 • Certain uses of the "sort" operator are optimised to modify an
2127 array in place, such as "@a = sort @a". During the sorting, the
2128 array is made read-only. If a sort block should happen to die,
2129 then the array remained read-only even outside the "sort". This
2130 has been fixed.
2131 • $a and $b inside a sort block are aliased to the actual arguments
2133 to "sort", so they can be modified through those two variables.
2134 This did not always work, e.g., for lvalue subs and $#ary, and
2135 probably many other operators. It works now.
2136 • The arguments to "sort" are now all in list context. If the "sort"
2138 itself were called in void or scalar context, then some, but not
2139 all, of the arguments used to be in void or scalar context.
2140 • Subroutine prototypes with Unicode characters above U+00FF were
2142 getting mangled during closure cloning. This would happen with
2143 subroutines closing over lexical variables declared outside, and
2144 with lexical subs.
2145 • "UNIVERSAL::can" now treats its first argument the same way that
2147 method calls do: Typeglobs and glob references with non-empty IO
2148 slots are treated as handles, and strings are treated as
2149 filehandles, rather than packages, if a handle with that name
2150 exists [perl #113932].
2151 • Method calls on typeglobs (e.g., "*ARGV->getline") used to
2153 stringify the typeglob and then look it up again. Combined with
2154 changes in Perl 5.18.0, this allowed "*foo->bar" to call methods on
2155 the "foo" package (like "foo->bar"). In some cases it could cause
2156 the method to be called on the wrong handle. Now a typeglob
2157 argument is treated as a handle (just like "(\*foo)->bar"), or, if
2158 its IO slot is empty, an error is raised.
2159 • Assigning a vstring to a tied variable or to a subroutine argument
2161 aliased to a nonexistent hash or array element now works, without
2162 flattening the vstring into a regular string.
2163 • "pos", "tie", "tied" and "untie" did not work properly on
2165 subroutine arguments aliased to nonexistent hash and array elements
2166 [perl #77814, #27010].
2167 • The "=>" fat arrow operator can now quote built-in keywords even if
2169 it occurs on the next line, making it consistent with how it treats
2170 other barewords.
2171 • Autovivifying a subroutine stub via "\&$glob" started causing
2173 crashes in Perl 5.18.0 if the $glob was merely a copy of a real
2174 glob, i.e., a scalar that had had a glob assigned to it. This has
2175 been fixed. [perl #119051]
2176 • Perl used to leak an implementation detail when it came to
2178 referencing the return values of certain operators. "for ($a+$b) {
2179 warn \$_; warn \$_ }" used to display two different memory
2180 addresses, because the "\" operator was copying the variable.
2181 Under threaded builds, it would also happen for constants ("for(1)
2182 { ... }"). This has been fixed. [perl #21979, #78194, #89188,
2183 #109746, #114838, #115388]
2184 • The range operator ".." was returning the same modifiable scalars
2186 with each call, unless it was the only thing in a "foreach" loop
2187 header. This meant that changes to values within the list returned
2188 would be visible the next time the operator was executed. [perl
2189 #3105]
2190 • Constant folding and subroutine inlining no longer cause operations
2192 that would normally return new modifiable scalars to return read-
2193 only values instead.
2194 • Closures of the form "sub () { $some_variable }" are no longer
2196 inlined, causing changes to the variable to be ignored by callers
2197 of the subroutine. [perl #79908]
2198 • Return values of certain operators such as "ref" would sometimes be
2200 shared between recursive calls to the same subroutine, causing the
2201 inner call to modify the value returned by "ref" in the outer call.
2202 This has been fixed.
2203 • "__PACKAGE__" and constants returning a package name or hash key
2205 are now consistently read-only. In various previous Perl releases,
2206 they have become mutable under certain circumstances.
2207 • Enabling "used once" warnings no longer causes crashes on stash
2209 circularities created at compile time ("*Foo::Bar::Foo:: =
2210 *Foo::").
2211 • Undef constants used in hash keys ("use constant u => undef;
2213 $h{+u}") no longer produce "uninitialized" warnings at compile
2214 time.
2215 • Modifying a substitution target inside the substitution replacement
2217 no longer causes crashes.
2218 • The first statement inside a string eval used to use the wrong
2220 pragma setting sometimes during constant folding. "eval 'uc chr
2221 0xe0'" would randomly choose between Unicode, byte, and locale
2222 semantics. This has been fixed.
2223 • The handling of return values of @INC filters (subroutines returned
2225 by subroutines in @INC) has been fixed in various ways. Previously
2226 tied variables were mishandled, and setting $_ to a reference or
2227 typeglob could result in crashes.
2228 • The "SvPVbyte" XS function has been fixed to work with tied scalars
2230 returning something other than a string. It used to return utf8 in
2231 those cases where "SvPV" would.
2232 • Perl 5.18.0 inadvertently made "--" and "++" crash on dereferenced
2234 regular expressions, and stopped "++" from flattening vstrings.
2235 • "bless" no longer dies with "Can't bless non-reference value" if
2237 its first argument is a tied reference.
2238 • "reset" with an argument no longer skips copy-on-write scalars,
2240 regular expressions, typeglob copies, and vstrings. Also, when
2241 encountering those or read-only values, it no longer skips any
2242 array or hash with the same name.
2243 • "reset" with an argument now skips scalars aliased to typeglobs
2245 ("for $z (*foo) { reset "z" }"). Previously it would corrupt
2246 memory or crash.
2247 • "ucfirst" and "lcfirst" were not respecting the bytes pragma. This
2249 was a regression from Perl 5.12. [perl #117355]
2250 • Changes to "UNIVERSAL::DESTROY" now update DESTROY caches in all
2252 classes, instead of causing classes that have already had objects
2253 destroyed to continue using the old sub. This was a regression in
2254 Perl 5.18. [perl #114864]
2255 • All known false-positive occurrences of the deprecation warning
2257 "Useless use of '\'; doesn't escape metacharacter '%c'", added in
2258 Perl 5.18.0, have been removed. [perl #119101]
2259 • The value of $^E is now saved across signal handlers on Windows.
2261 [perl #85104]
2262 • A lexical filehandle (as in "open my $fh...") is usually given a
2264 name based on the current package and the name of the variable,
2265 e.g. "main::$fh". Under recursion, the filehandle was losing the
2266 "$fh" part of the name. This has been fixed.
2267 • Uninitialized values returned by XSUBs are no longer exempt from
2269 uninitialized warnings. [perl #118693]
2270 • "elsif ("")" no longer erroneously produces a warning about void
2272 context. [perl #118753]
2273 • Passing "undef" to a subroutine now causes @_ to contain the same
2275 read-only undefined scalar that "undef" returns. Furthermore,
2276 "exists $_[0]" will now return true if "undef" was the first
2277 argument. [perl #7508, #109726]
2278 • Passing a non-existent array element to a subroutine does not
2280 usually autovivify it unless the subroutine modifies its argument.
2281 This did not work correctly with negative indices and with non-
2282 existent elements within the array. The element would be vivified
2283 immediately. The delayed vivification has been extended to work
2284 with those. [perl #118691]
2285 • Assigning references or globs to the scalar returned by $#foo after
2287 the @foo array has been freed no longer causes assertion failures
2288 on debugging builds and memory leaks on regular builds.
2289 • On 64-bit platforms, large ranges like 1..1000000000000 no longer
2291 crash, but eat up all your memory instead. [perl #119161]
2292 • "__DATA__" now puts the "DATA" handle in the right package, even if
2294 the current package has been renamed through glob assignment.
2295 • When "die", "last", "next", "redo", "goto" and "exit" unwind the
2297 scope, it is possible for "DESTROY" recursively to call a
2298 subroutine or format that is currently being exited. It that case,
2299 sometimes the lexical variables inside the sub would start out
2300 having values from the outer call, instead of being undefined as
2301 they should. This has been fixed. [perl #119311]
2302 • ${^MPEN} is no longer treated as a synonym for ${^MATCH}.
2304 • Perl now tries a little harder to return the correct line number in
2306 "(caller)[2]". [perl #115768]
2307 • Line numbers inside multiline quote-like operators are now reported
2309 correctly. [perl #3643]
2310 • "#line" directives inside code embedded in quote-like operators are
2312 now respected.
2313 • Line numbers are now correct inside the second here-doc when two
2315 here-doc markers occur on the same line.
2316 • An optimization in Perl 5.18 made incorrect assumptions causing a
2318 bad interaction with the Devel::CallParser CPAN module. If the
2319 module was loaded then lexical variables declared in separate
2320 statements following a "my(...)" list might fail to be cleared on
2321 scope exit.
2322 • &xsub and "goto &xsub" calls now allow the called subroutine to
2324 autovivify elements of @_.
2325 • &xsub and "goto &xsub" no longer crash if *_ has been undefined and
2327 has no ARRAY entry (i.e. @_ does not exist).
2328 • &xsub and "goto &xsub" now work with tied @_.
2330 • Overlong identifiers no longer cause a buffer overflow (and a
2332 crash). They started doing so in Perl 5.18.
2333 • The warning "Scalar value @hash{foo} better written as $hash{foo}"
2335 now produces far fewer false positives. In particular,
2336 @hash{+function_returning_a_list} and @hash{ qw "foo bar baz" } no
2337 longer warn. The same applies to array slices. [perl #28380,
2338 #114024]
2339 • "$! = EINVAL; waitpid(0, WNOHANG);" no longer goes into an internal
2341 infinite loop. [perl #85228]
2342 • A possible segmentation fault in filehandle duplication has been
2344 fixed.
2345 • A subroutine in @INC can return a reference to a scalar containing
2347 the initial contents of the file. However, that scalar was freed
2348 prematurely if not referenced elsewhere, giving random results.
2349 • "last" no longer returns values that the same statement has
2351 accumulated so far, fixing amongst other things the long-standing
2352 bug that "push @a, last" would try to return the @a, copying it
2353 like a scalar in the process and resulting in the error, "Bizarre
2354 copy of ARRAY in last." [perl #3112]
2355 • In some cases, closing file handles opened to pipe to or from a
2357 process, which had been duplicated into a standard handle, would
2358 call perl's internal waitpid wrapper with a pid of zero. With the
2359 fix for [perl #85228] this zero pid was passed to "waitpid",
2360 possibly blocking the process. This wait for process zero no
2361 longer occurs. [perl #119893]
2362 • "select" used to ignore magic on the fourth (timeout) argument,
2364 leading to effects such as "select" blocking indefinitely rather
2365 than the expected sleep time. This has now been fixed. [perl
2366 #120102]
2367 • The class name in "for my class $foo" is now parsed correctly. In
2369 the case of the second character of the class name being followed
2370 by a digit (e.g. 'a1b') this used to give the error "Missing $ on
2371 loop variable". [perl #120112]
2372 • Perl 5.18.0 accidentally disallowed "-bareword" under "use strict"
2374 and "use integer". This has been fixed. [perl #120288]
2375 • "-a" at the start of a line (or a hyphen with any single letter
2377 that is not a filetest operator) no longer produces an erroneous
2378 'Use of "-a" without parentheses is ambiguous' warning. [perl
2379 #120288]
2380 • Lvalue context is now properly propagated into bare blocks and "if"
2382 and "else" blocks in lvalue subroutines. Previously, arrays and
2383 hashes would sometimes incorrectly be flattened when returned in
2384 lvalue list context, or "Bizarre copy" errors could occur. [perl
2385 #119797]
2386 • Lvalue context is now propagated to the branches of "||" and "&&"
2388 (and their alphabetic equivalents, "or" and "and"). This means
2389 "foreach (pos $x || pos $y) {...}" now allows "pos" to be modified
2390 through $_.
2391 • "stat" and "readline" remember the last handle used; the former for
2393 the special "_" filehandle, the latter for "${^LAST_FH}". "eval
2394 "*foo if 0"" where *foo was the last handle passed to "stat" or
2395 "readline" could cause that handle to be forgotten if the handle
2396 were not opened yet. This has been fixed.
2397 • Various cases of "delete $::{a}", "delete $::{ENV}" etc. causing a
2399 crash have been fixed. [perl #54044]
2400 • Setting $! to EACCESS before calling "require" could affect
2402 "require"'s behaviour. This has been fixed.
2403 • The "Can't use \1 to mean $1 in expression" warning message now
2405 only occurs on the right-hand (replacement) part of a substitution.
2406 Formerly it could happen in code embedded in the left-hand side, or
2407 in any other quote-like operator.
2408 • Blessing into a reference ("bless $thisref, $thatref") has long
2410 been disallowed, but magical scalars for the second like $/ and
2411 those tied were exempt. They no longer are. [perl #119809]
2412 • Blessing into a reference was accidentally allowed in 5.18 if the
2414 class argument were a blessed reference with stale method caches
2415 (i.e., whose class had had subs defined since the last method
2416 call). They are disallowed once more, as in 5.16.
2417 • "$x->{key}" where $x was declared as "my Class $x" no longer
2419 crashes if a Class::FIELDS subroutine stub has been declared.
2420 • @$obj{'key'} and "${$obj}{key}" used to be exempt from compile-time
2422 field checking ("No such class field"; see fields) but no longer
2423 are.
2424 • A nonexistent array element with a large index passed to a
2426 subroutine that ties the array and then tries to access the element
2427 no longer results in a crash.
2428 • Declaring a subroutine stub named NEGATIVE_INDICES no longer makes
2430 negative array indices crash when the current package is a tied
2431 array class.
2432 • Declaring a "require", "glob", or "do" subroutine stub in the
2434 CORE::GLOBAL:: package no longer makes compilation of calls to the
2435 corresponding functions crash.
2436 • Aliasing CORE::GLOBAL:: functions to constants stopped working in
2438 Perl 5.10 but has now been fixed.
2439 • When "`...`" or "qx/.../" calls a "readpipe" override, double-
2441 quotish interpolation now happens, as is the case when there is no
2442 override. Previously, the presence of an override would make these
2443 quote-like operators act like "q{}", suppressing interpolation.
2444 [perl #115330]
2445 • "<<<`...`" here-docs (with backticks as the delimiters) now call
2447 "readpipe" overrides. [perl #119827]
2448 • "&CORE::exit()" and "&CORE::die()" now respect vmsish hints.
2450 • Undefining a glob that triggers a DESTROY method that undefines the
2452 same glob is now safe. It used to produce "Attempt to free
2453 unreferenced glob pointer" warnings and leak memory.
2454 • If subroutine redefinition ("eval 'sub foo{}'" or "newXS" for XS
2456 code) triggers a DESTROY method on the sub that is being redefined,
2457 and that method assigns a subroutine to the same slot ("*foo = sub
2458 {}"), $_[0] is no longer left pointing to a freed scalar. Now
2459 DESTROY is delayed until the new subroutine has been installed.
2460 • On Windows, perl no longer calls CloseHandle() on a socket handle.
2462 This makes debugging easier on Windows by removing certain
2463 irrelevant bad handle exceptions. It also fixes a race condition
2464 that made socket functions randomly fail in a Perl process with
2465 multiple OS threads, and possible test failures in
2466 dist/IO/t/cachepropagate-tcp.t. [perl #120091/118059]
2467 • Formats involving UTF-8 encoded strings, or strange vars like ties,
2469 overloads, or stringified refs (and in recent perls, pure NOK vars)
2470 would generally do the wrong thing in formats when the var is
2471 treated as a string and repeatedly chopped, as in "^<<<~~" and
2472 similar. This has now been resolved. [perl
2473 #33832/45325/113868/119847/119849/119851]
2474 • "semctl(..., SETVAL, ...)" would set the semaphore to the top
2476 32-bits of the supplied integer instead of the bottom 32-bits on
2477 64-bit big-endian systems. [perl #120635]
2478 • "readdir()" now only sets $! on error. $! is no longer set to
2480 "EBADF" when then terminating "undef" is read from the directory
2481 unless the system call sets $!. [perl #118651]
2482 • &CORE::glob no longer causes an intermittent crash due to perl's
2484 stack getting corrupted. [perl #119993]
2485 • "open" with layers that load modules (e.g., "<:encoding(utf8)") no
2487 longer runs the risk of crashing due to stack corruption.
2488 • Perl 5.18 broke autoloading via "->SUPER::foo" method calls by
2490 looking up AUTOLOAD from the current package rather than the
2491 current package's superclass. This has been fixed. [perl #120694]
2492 • A longstanding bug causing "do {} until CONSTANT", where the
2494 constant holds a true value, to read unallocated memory has been
2495 resolved. This would usually happen after a syntax error. In past
2496 versions of Perl it has crashed intermittently. [perl #72406]
2497 • Fix HP-UX $! failure. HP-UX strerror() returns an empty string for
2499 an unknown error code. This caused an assertion to fail under
2500 DEBUGGING builds. Now instead, the returned string for "$!"
2501 contains text indicating the code is for an unknown error.
2502 • Individually-tied elements of @INC (as in "tie $INC[0]...") are now
2504 handled correctly. Formerly, whether a sub returned by such a tied
2505 element would be treated as a sub depended on whether a FETCH had
2506 occurred previously.
2507 • "getc" on a byte-sized handle after the same "getc" operator had
2509 been used on a utf8 handle used to treat the bytes as utf8,
2510 resulting in erratic behavior (e.g., malformed UTF-8 warnings).
2511 • An initial "{" at the beginning of a format argument line was
2513 always interpreted as the beginning of a block prior to v5.18. In
2514 Perl v5.18, it started being treated as an ambiguous token. The
2515 parser would guess whether it was supposed to be an anonymous hash
2516 constructor or a block based on the contents. Now the previous
2517 behaviour has been restored. [perl #119973]
2518 • In Perl v5.18 "undef *_; goto &sub" and "local *_; goto &sub"
2520 started crashing. This has been fixed. [perl #119949]
2521 • Backticks (" `` " or " qx// ") combined with multiple threads on
2523 Win32 could result in output sent to stdout on one thread being
2524 captured by backticks of an external command in another thread.
2525 This could occur for pseudo-forked processes too, as Win32's
2527 pseudo-fork is implemented in terms of threads. [perl #77672]
2528 • "open $fh, ">+", undef" no longer leaks memory when TMPDIR is set
2530 but points to a directory a temporary file cannot be created in.
2531 [perl #120951]
2532 • " for ( $h{k} || '' ) " no longer auto-vivifies $h{k}. [perl
2534 #120374]
2535 • On Windows machines, Perl now emulates the POSIX use of the
2537 environment for locale initialization. Previously, the environment
2538 was ignored. See "ENVIRONMENT" in perllocale.
2539 • Fixed a crash when destroying a self-referencing GLOB. [perl
2541 #121242]
2542
2544 • IO::Socket is known to fail tests on AIX 5.3. There is a patch
2545 <https://github.com/Perl/perl5/issues/13484> in the request
2546 tracker, #120835, which may be applied to future releases.
2547 • The following modules are known to have test failures with this
2549 version of Perl. Patches have been submitted, so there will
2550 hopefully be new releases soon:
2551 • Data::Structure::Util version 0.15
2553 • HTML::StripScripts version 1.05
2555 • List::Gather version 0.08.
2557
2559 Diana Rosa, 27, of Rio de Janeiro, went to her long rest on May 10,
2560 2014, along with the plush camel she kept hanging on her computer
2561 screen all the time. She was a passionate Perl hacker who loved the
2562 language and its community, and who never missed a Rio.pm event. She
2563 was a true artist, an enthusiast about writing code, singing arias and
2564 graffiting walls. We'll never forget you.
2565 Greg McCarroll died on August 28, 2013.
2567 Greg was well known for many good reasons. He was one of the organisers
2569 of the first YAPC::Europe, which concluded with an unscheduled auction
2570 where he frantically tried to raise extra money to avoid the conference
2571 making a loss. It was Greg who mistakenly arrived for a london.pm
2572 meeting a week late; some years later he was the one who sold the
2573 choice of official meeting date at a YAPC::Europe auction, and
2574 eventually as glorious leader of london.pm he got to inherit the
2575 irreverent confusion that he had created.
2576 Always helpful, friendly and cheerfully optimistic, you will be missed,
2578 but never forgotten.
2579
2581 Perl 5.20.0 represents approximately 12 months of development since
2582 Perl 5.18.0 and contains approximately 470,000 lines of changes across
2583 2,900 files from 124 authors.
2584 Excluding auto-generated files, documentation and release tools, there
2586 were approximately 280,000 lines of changes to 1,800 .pm, .t, .c and .h
2587 files.
2588 Perl continues to flourish into its third decade thanks to a vibrant
2590 community of users and developers. The following people are known to
2591 have contributed the improvements that became Perl 5.20.0:
2592 Aaron Crane, Abhijit Menon-Sen, Abigail, Abir Viqar, Alan Haggai Alavi,
2594 Alan Hourihane, Alexander Voronov, Alexandr Ciornii, Andy Dougherty,
2595 Anno Siegel, Aristotle Pagaltzis, Arthur Axel 'fREW' Schmidt, Brad
2596 Gilbert, Brendan Byrd, Brian Childs, Brian Fraser, Brian Gottreu, Chris
2597 'BinGOs' Williams, Christian Millour, Colin Kuskie, Craig A. Berry,
2598 Dabrien 'Dabe' Murphy, Dagfinn Ilmari Mannsaaker, Daniel Dragan, Darin
2599 McBride, David Golden, David Leadbeater, David Mitchell, David Nicol,
2600 David Steinbrunner, Dennis Kaarsemaker, Dominic Hargreaves, Ed Avis,
2601 Eric Brine, Evan Zacks, Father Chrysostomos, Florian Ragwitz, Francois
2602 Perrad, Gavin Shelley, Gideon Israel Dsouza, Gisle Aas, Graham Knop,
2603 H.Merijn Brand, Hauke D, Heiko Eissfeldt, Hiroo Hayashi, Hojung Youn,
2604 James E Keenan, Jarkko Hietaniemi, Jerry D. Hedden, Jess Robinson,
2605 Jesse Luehrs, Johan Vromans, John Gardiner Myers, John Goodyear, John
2606 P. Linderman, John Peacock, kafka, Kang-min Liu, Karen Etheridge, Karl
2607 Williamson, Keedi Kim, Kent Fredric, kevin dawson, Kevin Falcone, Kevin
2608 Ryde, Leon Timmermans, Lukas Mai, Marc Simpson, Marcel Gruenauer, Marco
2609 Peereboom, Marcus Holland-Moritz, Mark Jason Dominus, Martin McGrath,
2610 Matthew Horsfall, Max Maischein, Mike Doherty, Moritz Lenz, Nathan
2611 Glenn, Nathan Trapuzzano, Neil Bowers, Neil Williams, Nicholas Clark,
2612 Niels Thykier, Niko Tyni, Olivier Mengue, Owain G. Ainsworth, Paul
2613 Green, Paul Johnson, Peter John Acklam, Peter Martini, Peter Rabbitson,
2614 Petr PisaX, Philip Boulain, Philip Guenther, Piotr Roszatycki, Rafael
2615 Garcia-Suarez, Reini Urban, Reuben Thomas, Ricardo Signes, Ruslan
2616 Zakirov, Sergey Alekseev, Shirakata Kentaro, Shlomi Fish, Slaven Rezic,
2617 Smylers, Steffen Mueller, Steve Hay, Sullivan Beck, Thomas Sibley,
2618 Tobias Leich, Toby Inkster, Tokuhiro Matsuno, Tom Christiansen, Tom
2619 Hukins, Tony Cook, Victor Efimov, Viktor Turskyi, Vladimir Timofeev,
2620 YAMASHINA Hio, Yves Orton, Zefram, Zsban Ambrus, AEvar Arnfjoerd`
2621 Bjarmason.
2622 The list above is almost certainly incomplete as it is automatically
2624 generated from version control history. In particular, it does not
2625 include the names of the (very much appreciated) contributors who
2626 reported issues to the Perl bug tracker.
2627 Many of the changes included in this version originated in the CPAN
2629 modules included in Perl's core. We're grateful to the entire CPAN
2630 community for helping Perl to flourish.
2631 For a more complete list of all of Perl's historical contributors,
2633 please see the AUTHORS file in the Perl source distribution.
2634
2636 If you find what you think is a bug, you might check the articles
2637 recently posted to the comp.lang.perl.misc newsgroup and the perl bug
2638 database at http://rt.perl.org/perlbug/ . There may also be
2639 information at http://www.perl.org/ , the Perl Home Page.
2640 If you believe you have an unreported bug, please run the perlbug
2642 program included with your release. Be sure to trim your bug down to a
2643 tiny but sufficient test case. Your bug report, along with the output
2644 of "perl -V", will be sent off to perlbug@perl.org to be analysed by
2645 the Perl porting team.
2646 If the bug you are reporting has security implications, which make it
2648 inappropriate to send to a publicly archived mailing list, then please
2649 send it to perl5-security-report@perl.org. This points to a closed
2650 subscription unarchived mailing list, which includes all the core
2651 committers, who will be able to help assess the impact of issues,
2652 figure out a resolution, and help co-ordinate the release of patches to
2653 mitigate or fix the problem across all platforms on which Perl is
2654 supported. Please only use this address for security issues in the
2655 Perl core, not for modules independently distributed on CPAN.
2656
2658 The Changes file for an explanation of how to view exhaustive details
2659 on what changed.
2660 The INSTALL file for how to build Perl.
2662 The README file for general stuff.
2664 The Artistic and Copying files for copyright information.
2666perl v5.34.0 2021-10-18 PERL5200DELTA(1)