1PERLDELTA(1) Perl Programmers Reference Guide PERLDELTA(1)
2
6 perldelta - what is new for perl v5.36.0
7
9 This document describes differences between the 5.34.0 release and the
10 5.36.0 release.
11
13 "use v5.36"
14 As always, "use v5.36" turns on the feature bundle for that version of
15 Perl.
16 The 5.36 bundle enables the "signatures" feature. Introduced in Perl
18 version 5.20.0, and modified several times since, the subroutine
19 signatures feature is now no longer considered experimental. It is now
20 considered a stable language feature and no longer prints a warning.
21 use v5.36;
23 sub add ($x, $y) {
25 return $x + $y;
26 }
27 Despite this, certain elements of signatured subroutines remain
29 experimental; see below.
30 The 5.36 bundle enables the "isa" feature. Introduced in Perl version
32 5.32.0, this operator has remained unchanged since then. The operator
33 is now considered a stable language feature. For more detail see
34 "Class Instance Operator" in perlop.
35 The 5.36 bundle also disables the features "indirect", and
37 "multidimensional". These will forbid, respectively: the use of
38 "indirect" method calls (like "$x = new Class;"); the use of a list
39 expression as a hash key to simulate sparse multidimensional arrays.
40 The specifics of these changes can be found in feature, but the short
41 version is: this is a bit like having more "use strict" turned on,
42 disabling features that cause more trouble than they're worth.
43 Furthermore, "use v5.36" will also enable warnings as if you'd written
45 "use warnings".
46 Finally, with this release, the experimental "switch" feature, present
48 in every feature bundle since they were introduced in v5.10, has been
49 removed from the v5.36 bundle. If you want to use it (against our
50 advice), you'll have to enable it explicitly.
51 -g command-line flag
53 A new command-line flag, -g, is available. It is a simpler alias for
54 -0777.
55 For more information, see "-g" in perlrun.
57 Unicode 14.0 is supported
59 See <https://www.unicode.org/versions/Unicode14.0.0/> for details.
60 regex sets are no longer considered experimental
62 Prior to this release, the regex sets feature (officially named
63 "Extended Bracketed Character Classes") was considered experimental.
64 Introduced in Perl version 5.18.0, and modified several times since,
65 this is now considered a stable language feature and its use no longer
66 prints a warning. See "Extended Bracketed Character Classes" in
67 perlrecharclass.
68 Variable length lookbehind is mostly no longer considered experimental
70 Prior to this release, any form of variable length lookbehind was
71 considered experimental. With this release the experimental status has
72 been reduced to cover only lookbehind that contains capturing
73 parenthesis. This is because it is not clear if
74 "aaz"=~/(?=z)(?<=(a|aa))/
76 should match and leave $1 equaling "a" or "aa". Currently it will match
78 the longest possible alternative, "aa". While we are confident that the
79 overall construct will now match only when it should, we are not
80 confident that we will keep the current "longest match" behavior.
81 SIGFPE no longer deferred
83 Floating-point exceptions are now delivered immediately, in the same
84 way as other "fault"-like signals such as SIGSEGV. This means one has
85 at least a chance to catch such a signal with a $SIG{FPE} handler, e.g.
86 so that "die" can report the line in perl that triggered it.
87 Stable boolean tracking
89 The "true" and "false" boolean values, often accessed by constructions
90 like "!!0" and "!!1", as well as being returned from many core
91 functions and operators, now remember their boolean nature even through
92 assignment into variables. The new function "is_bool()" in builtin can
93 check whether a value has boolean nature.
94 This is likely to be useful when interoperating with other languages or
96 data-type serialisation, among other places.
97 iterating over multiple values at a time (experimental)
99 You can now iterate over multiple values at a time by specifying a list
100 of lexicals within parentheses. For example,
101 for my ($key, $value) (%hash) { ... }
103 for my ($left, $right, $gripping) (@moties) { ... }
104 Prior to perl v5.36, attempting to specify a list after "for my" was a
106 syntax error.
107 This feature is currently experimental and will cause a warning of
109 category "experimental::for_list". For more detail see "Compound
110 Statements" in perlsyn. See also "builtin::indexed" in this document,
111 which is a handy companion to n-at-a-time foreach.
112 builtin functions (experimental)
114 A new core module builtin has been added, which provides documentation
115 for new always-present functions that are built into the interpreter.
116 say "Reference type of arrays is ", builtin::reftype([]);
118 It also provides a lexical import mechanism for providing short name
120 versions of these functions.
121 use builtin 'reftype';
123 say "Reference type of arrays is ", reftype([]);
124 This builtin function mechanism and the functions it provides are all
126 currently experimental. We expect that "builtin" itself will cease to
127 be experimental in the near future, but that individual functions in it
128 may become stable on an ongoing basis. Other functions will be added
129 to "builtin" over time.
130 For details, see builtin, but here's a summary of builtin functions in
132 v5.36:
133 builtin::trim
135 This function treats its argument as a string, returning the result
136 of removing all white space at its beginning and ending.
137 builtin::indexed
139 This function returns a list twice as big as its argument list,
140 where each item is preceded by its index within that list. This is
141 primarily useful for using the new "foreach" syntax with multiple
142 iterator variables to iterate over an array or list, while also
143 tracking the index of each item:
144 use builtin 'indexed';
146 foreach my ($index, $val) (indexed @array) {
148 ...
149 }
150 builtin::true, builtin::false, builtin::is_bool
152 "true" and "false" return boolean true and false values. Perl is
153 still perl, and doesn't have strict typing of booleans, but these
154 values will be known to have been created as booleans. "is_bool"
155 will tell you whether a value was known to have been created as a
156 boolean.
157 builtin::weaken, builtin::unweaken, builtin::is_weak
159 These functions will, respectively: weaken a reference; strengthen
160 a reference; and return whether a reference is weak. (A weak
161 reference is not counted for garbage collection purposes. See
162 perlref.) These can take the place of some similar routines in
163 Scalar::Util.
164 builtin::blessed, builtin::refaddr, builtin::reftype
166 These functions provide more data about references (or non-
167 references, actually!) and can take the place of similar routines
168 found in Scalar::Util.
169 builtin::ceil, builtin::floor
171 "ceil" returns the smallest integer greater than or equal to its
172 argument. "floor" returns the largest integer less than or equal
173 to its argument. These can take the place of similar routines
174 found in POSIX.
175 "defer" blocks (experimental)
177 This release adds support for "defer" blocks, which are blocks of code
178 prefixed by the "defer" modifier. They provide a section of code which
179 runs at a later time, during scope exit.
180 In brief, when a "defer" block is reached at runtime, its body is set
182 aside to be run when the enclosing scope is exited. It is unlike a
183 UNITCHECK (among other reasons) in that if the block containing the
184 "defer" block is exited before the block is reached, it will not be
185 run.
186 "defer" blocks can be used to take the place of "scope guard" objects
188 where an object is passed a code block to be run by its destructor.
189 For more information, see "defer blocks" in perlsyn.
191 try/catch can now have a "finally" block (experimental)
193 The experimental "try"/"catch" syntax has been extended to support an
194 optional third block introduced by the "finally" keyword.
195 try {
197 attempt();
198 print "Success\n";
199 }
200 catch ($e) {
201 print "Failure\n";
202 }
203 finally {
204 print "This happens regardless\n";
205 }
206 This provides code which runs at the end of the "try"/"catch"
208 construct, even if aborted by an exception or control-flow keyword.
209 They are similar to "defer" blocks.
210 For more information, see "Try Catch Exception Handling" in perlsyn.
212 non-ASCII delimiters for quote-like operators (experimental)
214 Perl traditionally has allowed just four pairs of string/pattern
215 delimiters: "( )" "{ }" "[ ]" and "< >", all in the ASCII range.
216 Unicode has hundreds more possibilities, and using this feature enables
217 many of them. When enabled, you can say "qrX X" for example, or
218 "use utf8; qXstringX". See "The 'extra_paired_delimiters' feature" in
219 feature for details.
220 @_ is now experimental within signatured subs
222 Even though subroutine signatures are now stable, use of the legacy
223 arguments array (@_) with a subroutine that has a signature remains
224 experimental, with its own warning category. Silencing the
225 "experimental::signatures" warning category is not sufficient to
226 dismiss this. The new warning is emitted with the category name
227 "experimental::args_array_with_signatures".
228 Any subroutine that has a signature and tries to make use of the
230 defaults argument array or an element thereof (@_ or $_[INDEX]), either
231 explicitly or implicitly (such as "shift" or "pop" with no argument)
232 will provoke a warning at compile-time:
233 use v5.36;
235 sub f ($x, $y = 123) {
237 say "The first argument is $_[0]";
238 }
239 Use of @_ in array element with signatured subroutine is experimental
241 at file.pl line 4.
242 The behaviour of code which attempts to do this is no longer specified,
244 and may be subject to change in a future version.
245
247 A physically empty sort is now a compile-time error
248 @a = sort @empty; # unaffected
249 @a = sort; # now a compile-time error
250 @a = sort (); # also a compile-time error
251 A bare sort used to be a weird way to create an empty list; now it
253 croaks at compile time. This change is intended to free up some of the
254 syntax space for possible future enhancements to "sort".
255
257 "use VERSION" (where VERSION is below v5.11) after "use v5.11" is
258 deprecated
259 When in the scope of "use v5.11" or later, a "use vX" line where X is
260 lower than v5.11 will now issue a warning:
261 Downgrading a use VERSION declaration to below v5.11 is deprecated
263 For example:
265 use v5.14;
267 say "The say statement is permitted";
268 use v5.8; # This will print a warning
269 print "We must use print\n";
270 This is because the Perl team plans to change the behavior in this
272 case. Since Perl v5.12 (and parts of v5.11), strict is enabled unless
273 it had previously been disabled. In other words:
274 no strict;
276 use v5.12; # will not enable strict, because "no strict" preceded it
277 $x = 1; # permitted, despite no "my" declaration
278 In the future, this behavior will be eliminated and "use VERSION" will
280 always enable strict for versions v5.12 and later.
281 Code which wishes to mix versions in this manner should use lexical
283 scoping with block syntax to ensure that the differently versioned
284 regions remain lexically isolated.
285 {
287 use v5.14;
288 say "The say statement is permitted";
289 }
290 {
292 use v5.8; # No warning is emitted
293 print "We must use print\n";
294 }
295 Of course, this is probably not something you ever need to do! If the
297 first block compiles, it means you're using perl v5.14.0 or later.
298
300 • We now probe for compiler support for C11 thread local storage, and
301 where available use this for "implicit context" for XS extensions
302 making API calls for a threaded Perl build. This requires fewer
303 function calls at the C level than POSIX thread specific storage.
304 We continue to use the the pthreads approach if the C11 approach is
305 not available.
306 Configure run with the defaults will build an unthreaded Perl
308 (which is slightly faster), but most operating systems ship a
309 threaded Perl.
310 • Perl can now be configured to no longer allocate keys for large
312 hashes from the shared string table.
313 The same internal datatype ("PVHV") is used for all of
315 • Symbol tables
317 • Objects (by default)
319 • Associative arrays
321 The shared string table was originally added to improve performance
323 for blessed hashes used as objects, because every object instance
324 has the same keys, so it is an optimisation to share memory between
325 them. It also makes sense for symbol tables, where derived classes
326 will have the same keys (typically method names), and the OP trees
327 built for method calls can also share memory. The shared string
328 table behaves roughly like a cache for hash keys.
329 But for hashes actually used as associative arrays - mapping keys
331 to values - typically the keys are not re-used in other hashes. For
332 example, "seen" hashes are keyed by object IDs (or addresses), and
333 logically these keys won't repeat in other hashes.
334 Storing these "used just once" keys in the shared string table
336 increases CPU and RAM use for no gain. For such keys the shared
337 string table behaves as a cache with a 0% hit rate. Storing all the
338 keys there increases the total size of the shared string table, as
339 well as increasing the number of times it is resized as it grows.
340 Worse - in any environment that has "copy on write" memory for
341 child process (such as a pre-forking server), the memory pages used
342 for the shared string table rapidly need to be copied as the child
343 process manipulates hashes. Hence if most of the shared string
344 table is such that keys are used only in one place, there is no
345 benefit from re-use within the perl interpreter, but a high cost
346 due to more pages for the OS to copy.
347 The perl interpreter can now be Configured to disable shared hash
349 keys for "large" hashes (that are neither objects nor symbol
350 tables). To do so, add
351 "-Accflags='-DPERL_USE_UNSHARED_KEYS_IN_LARGE_HASHES'" to your
352 Configure options. "Large" is a heuristic -- currently the
353 heuristic is that sharing is disabled when adding a key to a hash
354 triggers allocation of more storage, and the hash has more than 42
355 keys.
356 This might cause slightly increased memory usage for programs that
358 create (unblessed) data structures that contain multiple large
359 hashes that share the same keys. But generally our testing suggests
360 that for the specific cases described it is a win, and other code
361 is unaffected.
362 • In certain scenarios, creation of new scalars is now noticeably
364 faster.
365 For example, the following code is now executing ~30% faster:
367 $str = "A" x 64;
369 for (0..1_000_000) {
370 @svs = split //, $str
371 }
372 (You can read more about this one in [perl #19414]
374 <https://github.com/Perl/perl5/pull/19414>.)
375
377 Updated Modules and Pragmata
378 • Archive::Tar has been upgraded from version 2.38 to 2.40.
379 • Attribute::Handlers has been upgraded from version 1.01 to 1.02.
381 • attributes has been upgraded from version 0.33 to 0.34.
383 • B has been upgraded from version 1.82 to 1.83.
385 • B::Concise has been upgraded from version 1.004 to 1.006.
387 • B::Deparse has been upgraded from version 1.56 to 1.64.
389 • bignum has been upgraded from version 0.51 to 0.65.
391 • charnames has been upgraded from version 1.48 to 1.50.
393 • Compress::Raw::Bzip2 has been upgraded from version 2.101 to 2.103.
395 • Compress::Raw::Zlib has been upgraded from version 2.101 to 2.105.
397 • CPAN has been upgraded from version 2.28 to 2.33.
399 • Data::Dumper has been upgraded from version 2.179 to 2.184.
401 • DB_File has been upgraded from version 1.855 to 1.857.
403 • Devel::Peek has been upgraded from version 1.30 to 1.32.
405 • Devel::PPPort has been upgraded from version 3.62 to 3.68.
407 • diagnostics has been upgraded from version 1.37 to 1.39.
409 • Digest has been upgraded from version 1.19 to 1.20.
411 • DynaLoader has been upgraded from version 1.50 to 1.52.
413 • Encode has been upgraded from version 3.08 to 3.17.
415 • Errno has been upgraded from version 1.33 to 1.36.
417 • experimental has been upgraded from version 0.024 to 0.028.
419 • Exporter has been upgraded from version 5.76 to 5.77.
421 • ExtUtils::MakeMaker has been upgraded from version 7.62 to 7.64.
423 • ExtUtils::Miniperl has been upgraded from version 1.10 to 1.11.
425 • ExtUtils::ParseXS has been upgraded from version 3.43 to 3.45.
427 • ExtUtils::Typemaps has been upgraded from version 3.43 to 3.45.
429 • Fcntl has been upgraded from version 1.14 to 1.15.
431 • feature has been upgraded from version 1.64 to 1.72.
433 • File::Compare has been upgraded from version 1.1006 to 1.1007.
435 • File::Copy has been upgraded from version 2.35 to 2.39.
437 • File::Fetch has been upgraded from version 1.00 to 1.04.
439 • File::Find has been upgraded from version 1.39 to 1.40.
441 • File::Glob has been upgraded from version 1.33 to 1.37.
443 • File::Spec has been upgraded from version 3.80 to 3.84.
445 • File::stat has been upgraded from version 1.09 to 1.12.
447 • FindBin has been upgraded from version 1.52 to 1.53.
449 • GDBM_File has been upgraded from version 1.19 to 1.23.
451 • Hash::Util has been upgraded from version 0.25 to 0.28.
453 • Hash::Util::FieldHash has been upgraded from version 1.21 to 1.26.
455 • HTTP::Tiny has been upgraded from version 0.076 to 0.080.
457 • I18N::Langinfo has been upgraded from version 0.19 to 0.21.
459 • if has been upgraded from version 0.0609 to 0.0610.
461 • IO has been upgraded from version 1.46 to 1.50.
463 • IO-Compress has been upgraded from version 2.102 to 2.106.
465 • IPC::Open3 has been upgraded from version 1.21 to 1.22.
467 • JSON::PP has been upgraded from version 4.06 to 4.07.
469 • libnet has been upgraded from version 3.13 to 3.14.
471 • Locale::Maketext has been upgraded from version 1.29 to 1.31.
473 • Math::BigInt has been upgraded from version 1.999818 to 1.999830.
475 • Math::BigInt::FastCalc has been upgraded from version 0.5009 to
477 0.5012.
478 • Math::BigRat has been upgraded from version 0.2614 to 0.2621.
480 • Module::CoreList has been upgraded from version 5.20210520 to
482 5.20220520.
483 • mro has been upgraded from version 1.25_001 to 1.26.
485 • NEXT has been upgraded from version 0.68 to 0.69.
487 • Opcode has been upgraded from version 1.50 to 1.57.
489 • open has been upgraded from version 1.12 to 1.13.
491 • overload has been upgraded from version 1.33 to 1.35.
493 • perlfaq has been upgraded from version 5.20210411 to 5.20210520.
495 • PerlIO has been upgraded from version 1.11 to 1.12.
497 • Pod::Functions has been upgraded from version 1.13 to 1.14.
499 • Pod::Html has been upgraded from version 1.27 to 1.33.
501 • Pod::Simple has been upgraded from version 3.42 to 3.43.
503 • POSIX has been upgraded from version 1.97 to 2.03.
505 • re has been upgraded from version 0.41 to 0.43.
507 • Scalar::Util has been upgraded from version 1.55 to 1.62.
509 • sigtrap has been upgraded from version 1.09 to 1.10.
511 • Socket has been upgraded from version 2.031 to 2.033.
513 • sort has been upgraded from version 2.04 to 2.05.
515 • Storable has been upgraded from version 3.23 to 3.26.
517 • Sys::Hostname has been upgraded from version 1.23 to 1.24.
519 • Test::Harness has been upgraded from version 3.43 to 3.44.
521 • Test::Simple has been upgraded from version 1.302183 to 1.302190.
523 • Text::ParseWords has been upgraded from version 3.30 to 3.31.
525 • Text::Tabs has been upgraded from version 2013.0523 to 2021.0814.
527 • Text::Wrap has been upgraded from version 2013.0523 to 2021.0814.
529 • threads has been upgraded from version 2.26 to 2.27.
531 • threads::shared has been upgraded from version 1.62 to 1.64.
533 • Tie::Handle has been upgraded from version 4.2 to 4.3.
535 • Tie::Hash has been upgraded from version 1.05 to 1.06.
537 • Tie::Scalar has been upgraded from version 1.05 to 1.06.
539 • Tie::SubstrHash has been upgraded from version 1.00 to 1.01.
541 • Time::HiRes has been upgraded from version 1.9767 to 1.9770.
543 • Unicode::Collate has been upgraded from version 1.29 to 1.31.
545 • Unicode::Normalize has been upgraded from version 1.28 to 1.31.
547 • Unicode::UCD has been upgraded from version 0.75 to 0.78.
549 • UNIVERSAL has been upgraded from version 1.13 to 1.14.
551 • version has been upgraded from version 0.9928 to 0.9929.
553 • VMS::Filespec has been upgraded from version 1.12 to 1.13.
555 • VMS::Stdio has been upgraded from version 2.45 to 2.46.
557 • warnings has been upgraded from version 1.51 to 1.58.
559 • Win32 has been upgraded from version 0.57 to 0.59.
561 • XS::APItest has been upgraded from version 1.16 to 1.22.
563 • XS::Typemap has been upgraded from version 0.18 to 0.19.
565 • XSLoader has been upgraded from version 0.30 to 0.31.
567
569 New Documentation
570 Porting/vote_admin_guide.pod
571 This document provides the process for administering an election or
573 vote within the Perl Core Team.
574 Changes to Existing Documentation
576 We have attempted to update the documentation to reflect the changes
577 listed in this document. If you find any we have missed, open an issue
578 at <https://github.com/Perl/perl5/issues>.
579 Additionally, the following selected changes have been made:
581 perlapi
583 • This has been cleaned up some, and more than 80% of the (previously
585 many) undocumented functions have now either been documented or
586 deemed to have been inappropriately marked as API.
587 As always, Patches Welcome!
589 perldeprecation
591 • notes the new location for functions moved from Pod::Html to
593 Pod::Html::Util that are no longer intended to be used outside of
594 core.
595 perlexperiment
597 • notes the ":win32" IO pseudolayer is removed (this happened in
599 5.35.2).
600 perlgov
602 • The election process has been finetuned to allow the vote to be
604 skipped if there are no more candidates than open seats.
605 • A special election is now allowed to be postponed for up to twelve
607 weeks, for example until a normal election.
608 perlop
610 • now notes that an invocant only needs to be an object or class name
612 for method calls, not for subroutine references.
613 perlre
615 • Updated to discourage the use of the /d regexp modifier.
617 perlrun
619 • -? is now a synonym for -h
621 • -g is now a synonym for -0777
623
625 The following additions or changes have been made to diagnostic output,
626 including warnings and fatal error messages. For the complete list of
627 diagnostic messages, see perldiag.
628 New Diagnostics
630 New Errors
631 • Can't "%s" out of a "defer" block
633 (F) An attempt was made to jump out of the scope of a defer block
635 by using a control-flow statement such as "return", "goto" or a
636 loop control. This is not permitted.
637 • Can't modify %s in %s (for scalar assignment to "undef")
639 Attempting to perform a scalar assignment to "undef", for example
641 via "undef = $foo;", previously triggered a fatal runtime error
642 with the message "Modification of a read-only value attempted." It
643 is more helpful to detect such attempted assignments prior to
644 runtime, so they are now compile time errors, resulting in the
645 message "Can't modify undef operator in scalar assignment".
646 • panic: newFORLOOP, %s
648 The parser failed an internal consistency check while trying to
650 parse a "foreach" loop.
651 New Warnings
653 • Built-in function '%s' is experimental
655 A call is being made to a function in the "builtin::" namespace,
657 which is currently experimental.
658 • defer is experimental
660 The "defer" block modifier is experimental. If you want to use the
662 feature, disable the warning with "no warnings
663 'experimental::defer'", but know that in doing so you are taking
664 the risk that your code may break in a future Perl version.
665 • Downgrading a use VERSION declaration to below v5.11 is deprecated
667 This warning is emitted on a "use VERSION" statement that requests
669 a version below v5.11 (when the effects of "use strict" would be
670 disabled), after a previous declaration of one having a larger
671 number (which would have enabled these effects)
672 • for my (...) is experimental
674 This warning is emitted if you use "for" to iterate multiple values
676 at a time. This syntax is currently experimental and its behaviour
677 may change in future releases of Perl.
678 • Implicit use of @_ in %s with signatured subroutine is experimental
680 An expression that implicitly involves the @_ arguments array was
682 found in a subroutine that uses a signature.
683 • Use of @_ in %s with signatured subroutine is experimental
685 An expression involving the @_ arguments array was found in a
687 subroutine that uses a signature.
688 • Wide character in $0
690 Attempts to put wide characters into the program name ($0) now
692 provoke this warning.
693 Changes to Existing Diagnostics
695 • '/' does not take a repeat count in %s
696 This warning used to not include the "in %s".
698 • Subroutine %s redefined
700 Localized subroutine redefinitions no longer trigger this warning.
702 • unexpected constant lvalue entersub entry via type/targ %d:%d" now
704 has a panic prefix
705 This makes it consistent with other checks of internal consistency
707 when compiling a subroutine.
708 • Useless use of sort in scalar context is now in the new "scalar"
710 category.
711 When "sort" is used in scalar context, it provokes a warning that
713 doing this is not useful. This warning used to be in the "void"
714 category. A new category for warnings about scalar context has now
715 been added, called "scalar".
716 • Removed a number of diagnostics
718 Many diagnostics that have been removed from the perl core across
720 many years have now also been removed from the documentation.
721
723 • The Perl C source code now uses some C99 features, which we have
724 verified are supported by all compilers we target. This means that
725 Perl's headers now contain some code that is legal in C99 but not
726 C89.
727 This may cause problems for some XS modules that unconditionally
729 add "-Werror=declaration-after-statement" to their C compiler flags
730 if compiling with gcc or clang. Earlier versions of Perl support
731 long obsolete compilers that are strict in rejecting certain C99
732 features, particularly mixed declarations and code, and hence it
733 makes sense for XS module authors to audit that their code does not
734 violate this. However, doing this is now only possible on these
735 earlier versions of Perl, hence these modules need to be changed to
736 only add this flag for "<$] < 5.035005">.
737 • The makedepend step is now run in parallel by using make
739 When using MAKEFLAGS=-j8, this significantly reduces the time
741 required for:
742 sh ./makedepend MAKE=make cflags
744 • Configure now tests whether "#include <xlocale.h>" is required to
746 use the POSIX 1003 thread-safe locale functions or some related
747 extensions. This prevents problems where a non-public xlocale.h is
748 removed in a library update, or xlocale.h isn't intended for public
749 use. (github #18936 <https://github.com/Perl/perl5/pull/18936>)
750
752 Tests were added and changed to reflect the other additions and changes
753 in this release.
754
756 Windows
757 • Support for old MSVC++ (pre-VC12) has been removed
758 These did not support C99 and hence can no longer be used to
760 compile perl.
761 • Support for compiling perl on Windows using Microsoft Visual Studio
763 2022 (containing Visual C++ 14.3) has been added.
764 • The :win32 IO layer has been removed. This experimental replacement
766 for the :unix layer never reached maturity in its nearly two
767 decades of existence.
768 VMS
770 "keys %ENV" on VMS returns consistent results
771 On VMS entries in the %ENV hash are loaded from the OS environment
772 on first access, hence the first iteration of %ENV requires the
773 entire environment to be scanned to find all possible keys. This
774 initialisation had always been done correctly for full iteration,
775 but previously was not happening for %ENV in scalar context,
776 meaning that "scalar %ENV" would return 0 if called before any
777 other %ENV access, or would only return the count of keys accessed
778 if there had been no iteration.
779 These bugs are now fixed - %ENV and "keys %ENV" in scalar context
781 now return the correct result - the count of all keys in the
782 environment.
783 Discontinued Platforms
785 AT&T UWIN
786 UWIN is a UNIX compatibility layer for Windows. It was last
787 released in 2012 and has been superseded by Cygwin these days.
788 DOS/DJGPP
790 DJGPP is a port of the GNU toolchain to 32-bit x86 systems running
791 DOS. The last known attempt to build Perl on it was on 5.20, which
792 only got as far as building miniperl.
793 NetWare
795 Support code for Novell NetWare has been removed. NetWare was a
796 server operating system by Novell. The port was last updated in
797 July 2002, and the platform itself in May 2009.
798 Unrelated changes accidentally broke the build for the NetWare port
800 in September 2009, and in 12 years no-one has reported this.
801 Platform-Specific Notes
803 z/OS
804 This update enables us to build EBCDIC static/dynamic and
805 31-bit/64-bit addressing mode Perl. The number of tests that pass
806 is consistent with the baseline before these updates.
807 These changes also provide the base support to be able to provide
809 ASCII static/dynamic and 31-bit/64-bit addressing mode Perl.
810 The z/OS (previously called OS/390) README was updated to describe
812 ASCII and EBCDIC builds.
813
815 • Since the removal of PERL_OBJECT in Perl 5.8, PERL_IMPLICIT_CONTEXT
816 and MULTIPLICITY have been synonymous and they were being used
817 interchangeably. To simplify the code, all instances of
818 PERL_IMPLICIT_CONTEXT have been replaced with MULTIPLICITY.
819 PERL_IMPLICIT_CONTEXT will remain defined for compatibility with XS
821 modules.
822 • The API constant formerly named "G_ARRAY", indicating list context,
824 has now been renamed to a more accurate "G_LIST". A compatibilty
825 macro "G_ARRAY" has been added to allow existing code to work
826 unaffected. New code should be written using the new constant
827 instead. This is supported by "Devel::PPPort" version 3.63.
828 • Macros have been added to perl.h to facilitate version comparisons:
830 "PERL_GCC_VERSION_GE", "PERL_GCC_VERSION_GT", "PERL_GCC_VERSION_LE"
831 and "PERL_GCC_VERSION_LT".
832 Inline functions have been added to embed.h to determine the
834 position of the least significant 1 bit in a word: "lsbit_pos32"
835 and "lsbit_pos64".
836 • "Perl_ptr_table_clear" has been deleted. This has been marked as
838 deprecated since v5.14.0 (released in 2011), and is not used by any
839 code on CPAN.
840 • Added new boolean macros and functions. See "Stable boolean
842 tracking" for related information and perlapi for documentation.
843 • sv_setbool
845 • sv_setbool_mg
847 • SvIsBOOL
849 • Added 4 missing functions for dealing with RVs:
851 • sv_setrv_noinc
853 • sv_setrv_noinc_mg
855 • sv_setrv_inc
857 • sv_setrv_inc_mg
859 • "xs_handshake()"'s two failure modes now provide distinct messages.
861 • Memory for hash iterator state ("struct xpvhv_aux") is now
863 allocated as part of the hash body, instead of as part of the block
864 of memory allocated for the main hash array.
865 • A new phase_name() interface provides access to the name for each
867 interpreter phase (i.e., PL_phase value).
868 • The "pack" behavior of "U" has changed for EBCDIC.
870 • New equality-test functions "sv_numeq" and "sv_streq" have been
872 added, along with "..._flags"-suffixed variants. These expose a
873 simple and consistent API to perform numerical or string comparison
874 which is aware of operator overloading.
875 • Reading the string form of an integer value no longer sets the flag
877 "SVf_POK". The string form is still cached internally, and still
878 re-read directly by the macros "SvPV(sv)" etc (inline, without
879 calling a C function). XS code that already calls the APIs to get
880 values will not be affected by this change. XS code that accesses
881 flags directly instead of using API calls to express its intent
882 might break, but such code likely is already buggy if passed some
883 other values, such as floating point values or objects with string
884 overloading.
885 This small change permits code (such as JSON serializers) to
887 reliably determine between
888 • a value that was initially written as an integer, but then read
890 as a string
891 my $answer = 42;
893 print "The answer is $answer\n";
894 • that same value that was initially written as a string, but
896 then read as an integer
897 my $answer = "42";
899 print "That doesn't look right\n"
900 unless $answer == 6 * 9;
901 For the first case (originally written as an integer), we now have:
903 use Devel::Peek;
905 my $answer = 42;
906 Dump ($answer);
907 my $void = "$answer";
908 print STDERR "\n";
909 Dump($answer)
910 SV = IV(0x562538925778) at 0x562538925788
913 REFCNT = 1
914 FLAGS = (IOK,pIOK)
915 IV = 42
916 SV = PVIV(0x5625389263c0) at 0x562538925788
918 REFCNT = 1
919 FLAGS = (IOK,pIOK,pPOK)
920 IV = 42
921 PV = 0x562538919b50 "42"\0
922 CUR = 2
923 LEN = 10
924 For the second (originally written as a string), we now have:
926 use Devel::Peek;
928 my $answer = "42";
929 Dump ($answer);
930 my $void = $answer == 6 * 9;
931 print STDERR "\n";
932 Dump($answer)'
933 SV = PV(0x5586ffe9bfb0) at 0x5586ffec0788
936 REFCNT = 1
937 FLAGS = (POK,IsCOW,pPOK)
938 PV = 0x5586ffee7fd0 "42"\0
939 CUR = 2
940 LEN = 10
941 COW_REFCNT = 1
942 SV = PVIV(0x5586ffec13c0) at 0x5586ffec0788
944 REFCNT = 1
945 FLAGS = (IOK,POK,IsCOW,pIOK,pPOK)
946 IV = 42
947 PV = 0x5586ffee7fd0 "42"\0
948 CUR = 2
949 LEN = 10
950 COW_REFCNT = 1
951 (One can't rely on the presence or absence of the flag "SVf_IsCOW"
953 to determine the history of operations on a scalar.)
954 Previously both cases would be indistinguishable, with all 4 flags
956 set:
957 SV = PVIV(0x55d4d62edaf0) at 0x55d4d62f0930
959 REFCNT = 1
960 FLAGS = (IOK,POK,pIOK,pPOK)
961 IV = 42
962 PV = 0x55d4d62e1740 "42"\0
963 CUR = 2
964 LEN = 10
965 (and possibly "SVf_IsCOW", but not always)
967 This now means that if XS code really needs to determine which form
969 a value was first written as, it should implement logic roughly
970 if (flags & SVf_IOK|SVf_NOK) && !(flags & SVf_POK)
972 serialize as number
973 else if (flags & SVf_POK)
974 serialize as string
975 else
976 the existing guesswork ...
977 Note that this doesn't cover "dualvars" - scalars that report
979 different values when asked for their string form or number form
980 (such as $!). Most serialization formats cannot represent such
981 duplicity.
982 The existing guesswork remains because as well as dualvars, values
984 might be "undef", references, overloaded references, typeglobs and
985 other things that Perl itself can represent but do not map one-to-
986 one into external formats, so need some amount of approximation or
987 encapsulation.
988 • "sv_dump" (and Devel::PeekXs "Dump" function) now escapes high-bit
990 octets in the PV as hex rather than octal. Since most folks
991 understand hex more readily than octal, this should make these
992 dumps a bit more legible. This does not affect any other
993 diagnostic interfaces like "pv_display".
994
996 • utime() now correctly sets errno/$! when called on a closed handle.
997 • The flags on the OPTVAL parameter to setsockopt() were previously
999 checked before magic was called, possibly treating a numeric value
1000 as a packed buffer or vice versa. It also ignored the UTF-8 flag,
1001 potentially treating the internal representation of an upgraded SV
1002 as the bytes to supply to the setsockopt() system call. (github
1003 #18660 <https://github.com/Perl/perl5/issues/18660>)
1004 • Only set IOKp, not IOK on $) and $(. This was issue #18955
1006 <https://github.com/Perl/perl5/issues/18955>: This will prevent
1007 serializers from serializing these variables as numbers (which
1008 loses the additional groups). This restores behaviour from 5.16
1009 • Use of the "mktables" debugging facility would cause perl to croak
1011 since v5.31.10; this problem has now been fixed.
1012 • "makedepend" logic is now compatible with BSD make (fixes GH #19046
1014 <https://github.com/Perl/perl5/issues/19046>).
1015 • Calling "untie" on a tied hash that is partway through iteration
1017 now frees the iteration state immediately.
1018 Iterating a tied hash causes perl to store a copy of the current
1020 hash key to track the iteration state, with this stored copy passed
1021 as the second parameter to "NEXTKEY". This internal state is freed
1022 immediately when tie hash iteration completes, or if the hash is
1023 destroyed, but due to an implementation oversight, it was not freed
1024 if the hash was untied. In that case, the internal copy of the key
1025 would persist until the earliest of
1026 1. "tie" was called again on the same hash
1028 2. The (now untied) hash was iterated (ie passed to any of "keys",
1030 "values" or "each")
1031 3. The hash was destroyed.
1033 This inconsistency is now fixed - the internal state is now freed
1035 immediately by "untie".
1036 As the precise timing of this behaviour can be observed with pure
1038 Perl code (the timing of "DESTROY" on objects returned from
1039 "FIRSTKEY" and "NEXTKEY") it's just possible that some code is
1040 sensitive to it.
1041 • The "Internals::getcwd()" function added for bootstrapping miniperl
1043 in perl 5.30.0 is now only available in miniperl. [github #19122]
1044 • Setting a breakpoint on a BEGIN or equivalently a "use" statement
1046 could cause a memory write to a freed "dbstate" op. [GH #19198
1047 <https://github.com/Perl/perl5/issues/19198>]
1048 • When bareword filehandles are disabled, the parser was interpreting
1050 any bareword as a filehandle, even when immediatey followed by
1051 parens.
1052
1054 • perl5300delta mistakenly identified a CVE whose correct
1055 identification is CVE-2015-1592.
1056
1058 Raun "Spider" Boardman (SPIDB on CPAN), author of at least 66 commits
1059 to the Perl 5 core distribution between 1996 and 2002, passed away May
1060 24, 2021 from complications of COVID. He will be missed.
1061 David H. Adler (DHA) passed away on November 16, 2021. In 1997, David
1063 co-founded NY.pm, the first Perl user group, and in 1998 co-founded
1064 Perl Mongers to help establish other user groups across the globe. He
1065 was a frequent attendee at Perl conferences in both North America and
1066 Europe and well known for his role in organizing Bad Movie Night
1067 celebrations at those conferences. He also contributed to the work of
1068 the Perl Foundation, including administering the White Camel awards for
1069 community service. He will be missed.
1070
1072 Perl 5.36.0 represents approximately a year of development since Perl
1073 5.34.0 and contains approximately 250,000 lines of changes across 2,000
1074 files from 82 authors.
1075 Excluding auto-generated files, documentation and release tools, there
1077 were approximately 190,000 lines of changes to 1,300 .pm, .t, .c and .h
1078 files.
1079 Perl continues to flourish into its fourth decade thanks to a vibrant
1081 community of users and developers. The following people are known to
1082 have contributed the improvements that became Perl 5.36.0:
1083 Alyssa Ross, Andrew Fresh, Aristotle Pagaltzis, Asher Mancinelli,
1085 Atsushi Sugawara, Ben Cornett, Bernd, Biswapriyo Nath, Brad Barden,
1086 Bram, Branislav Zahradnik, brian d foy, Chad Granum, Chris 'BinGOs'
1087 Williams, Christian Walde (Mithaldu), Christopher Yeleighton, Craig A.
1088 Berry, cuishuang, Curtis Poe, Dagfinn Ilmari Mannsaaker, Dan Book,
1089 Daniel Lauegt, Dan Jacobson, Dan Kogai, Dave Cross, Dave Lambley, David
1090 Cantrell, David Golden, David Marshall, David Mitchell, E. Choroba,
1091 Eugen Konkov, Felipe Gasper, Francois Perrad, Graham Knop, H.Merijn
1092 Brand, Hugo van der Sanden, Ilya Sashcheka, Ivan Panchenko, Jakub Wilk,
1093 James E Keenan, James Raspass, Karen Etheridge, Karl Williamson, Leam
1094 Hall, Leon Timmermans, Magnus Woldrich, Matthew Horsfall, Max
1095 Maischein, Michael G Schwern, Michiel Beijen, Mike Fulton, Neil Bowers,
1096 Nicholas Clark, Nicolas R, Niyas Sait, Olaf Alders, Paul Evans, Paul
1097 Marquess, Petar-Kaleychev, Pete Houston, Renee Baecker, Ricardo Signes,
1098 Richard Leach, Robert Rothenberg, Sawyer X, Scott Baker, Sergey
1099 Poznyakoff, Sergey Zhmylove, Sisyphus, Slaven Rezic, Steve Hay, Sven
1100 Kirmess, TAKAI Kousuke, Thibault Duponchelle, Todd Rinaldo, Tomasz
1101 Konojacki, Tomoyuki Sadahiro, Tony Cook, Unicode Consortium, Yves
1102 Orton, XXXXXX XXXXXXXX.
1103 The list above is almost certainly incomplete as it is automatically
1105 generated from version control history. In particular, it does not
1106 include the names of the (very much appreciated) contributors who
1107 reported issues to the Perl bug tracker.
1108 Many of the changes included in this version originated in the CPAN
1110 modules included in Perl's core. We're grateful to the entire CPAN
1111 community for helping Perl to flourish.
1112 For a more complete list of all of Perl's historical contributors,
1114 please
1115
1117 If you find what you think is a bug, you might check the perl bug
1118 database at <https://github.com/Perl/perl5/issues>. There may also be
1119 information at <http://www.perl.org/>, the Perl Home Page.
1120 If you believe you have an unreported bug, please open an issue at
1122 <https://github.com/Perl/perl5/issues>. Be sure to trim your bug down
1123 to a tiny but sufficient test case.
1124 If the bug you are reporting has security implications which make it
1126 inappropriate to send to a public issue tracker, then see "SECURITY
1127 VULNERABILITY CONTACT INFORMATION" in perlsec for details of how to
1128 report the issue.
1129
1131 If you wish to thank the Perl 5 Porters for the work we had done in
1132 Perl 5, you can do so by running the "perlthanks" program:
1133 perlthanks
1135 This will send an email to the Perl 5 Porters list with your show of
1137 thanks.
1138
1140 The Changes file for an explanation of how to view exhaustive details
1141 on what changed.
1142 The INSTALL file for how to build Perl.
1144 The README file for general stuff.
1146 The Artistic and Copying files for copyright information.
1148perl v5.36.0 2022-08-30 PERLDELTA(1)