1PERL5240DELTA(1) Perl Programmers Reference Guide PERL5240DELTA(1)
2
6 perl5240delta - what is new for perl v5.24.0
7
9 This document describes the differences between the 5.22.0 release and
10 the 5.24.0 release.
11
13 Postfix dereferencing is no longer experimental
14 Using the "postderef" and "postderef_qq" features no longer emits a
15 warning. Existing code that disables the "experimental::postderef"
16 warning category that they previously used will continue to work. The
17 "postderef" feature has no effect; all Perl code can use postfix
18 dereferencing, regardless of what feature declarations are in scope.
19 The 5.24 feature bundle now includes the "postderef_qq" feature.
20 Unicode 8.0 is now supported
22 For details on what is in this release, see
23 <http://www.unicode.org/versions/Unicode8.0.0/>.
24 perl will now croak when closing an in-place output file fails
26 Until now, failure to close the output file for an in-place edit was
27 not detected, meaning that the input file could be clobbered without
28 the edit being successfully completed. Now, when the output file
29 cannot be closed successfully, an exception is raised.
30 New "\b{lb}" boundary in regular expressions
32 "lb" stands for Line Break. It is a Unicode property that determines
33 where a line of text is suitable to break (typically so that it can be
34 output without overflowing the available horizontal space). This
35 capability has long been furnished by the Unicode::LineBreak module,
36 but now a light-weight, non-customizable version that is suitable for
37 many purposes is in core Perl.
38 "qr/(?[ ])/" now works in UTF-8 locales
40 Extended Bracketed Character Classes now will successfully compile when
41 "use locale" is in effect. The compiled pattern will use standard
42 Unicode rules. If the runtime locale is not a UTF-8 one, a warning is
43 raised and standard Unicode rules are used anyway. No tainting is done
44 since the outcome does not actually depend on the locale.
45 Integer shift ("<<" and ">>") now more explicitly defined
47 Negative shifts are reverse shifts: left shift becomes right shift, and
48 right shift becomes left shift.
49 Shifting by the number of bits in a native integer (or more) is zero,
51 except when the "overshift" is right shifting a negative value under
52 "use integer", in which case the result is -1 (arithmetic shift).
53 Until now negative shifting and overshifting have been undefined
55 because they have relied on whatever the C implementation happens to
56 do. For example, for the overshift a common C behavior is "modulo
57 shift":
58 1 >> 64 == 1 >> (64 % 64) == 1 >> 0 == 1 # Common C behavior.
60 # And the same for <<, while Perl now produces 0 for both.
62 Now these behaviors are well-defined under Perl, regardless of what the
64 underlying C implementation does. Note, however, that you are still
65 constrained by the native integer width: you need to know how far left
66 you can go. You can use for example:
67 use Config;
69 my $wordbits = $Config{uvsize} * 8; # Or $Config{uvsize} << 3.
70 If you need a more bits on the left shift, you can use for example the
72 "bigint" pragma, or the "Bit::Vector" module from CPAN.
73 printf and sprintf now allow reordered precision arguments
75 That is, "sprintf '|%.*2$d|', 2, 3" now returns "|002|". This extends
76 the existing reordering mechanism (which allows reordering for
77 arguments that are used as format fields, widths, and vector
78 separators).
79 More fields provided to "sigaction" callback with "SA_SIGINFO"
81 When passing the "SA_SIGINFO" flag to sigaction, the "errno", "status",
82 "uid", "pid", "addr" and "band" fields are now included in the hash
83 passed to the handler, if supported by the platform.
84 Hashbang redirection to Perl 6
86 Previously perl would redirect to another interpreter if it found a
87 hashbang path unless the path contains "perl" (see perlrun). To improve
88 compatability with Perl 6 this behavior has been extended to also
89 redirect if "perl" is followed by "6".
90
92 Set proper umask before calling mkstemp(3)
93 In 5.22 perl started setting umask to 0600 before calling mkstemp(3)
94 and restoring it afterwards. This wrongfully tells open(2) to strip the
95 owner read and write bits from the given mode before applying it,
96 rather than the intended negation of leaving only those bits in place.
97 Systems that use mode 0666 in mkstemp(3) (like old versions of glibc)
99 create a file with permissions 0066, leaving world read and write
100 permissions regardless of current umask.
101 This has been fixed by using umask 0177 instead. [perl #127322]
103 Fix out of boundary access in Win32 path handling
105 This is CVE-2015-8608. For more information see [perl #126755]
106 <https://rt.perl.org/Ticket/Display.html?id=126755>
107 Fix loss of taint in canonpath
109 This is CVE-2015-8607. For more information see [perl #126862]
110 <https://rt.perl.org/Ticket/Display.html?id=126862>
111 Avoid accessing uninitialized memory in win32 "crypt()"
113 Added validation that will detect both a short salt and invalid
114 characters in the salt. [perl #126922]
115 <https://rt.perl.org/Ticket/Display.html?id=126922>
116 Remove duplicate environment variables from "environ"
118 Previously, if an environment variable appeared more than once in
119 "environ[]", %ENV would contain the last entry for that name, while a
120 typical "getenv()" would return the first entry. We now make sure %ENV
121 contains the same as what "getenv" returns.
122 Second, we remove duplicates from "environ[]", so if a setting with
124 that name is set in %ENV, we won't pass an unsafe value to a child
125 process.
126 [CVE-2016-2381]
128
130 The "autoderef" feature has been removed
131 The experimental "autoderef" feature (which allowed calling "push",
132 "pop", "shift", "unshift", "splice", "keys", "values", and "each" on a
133 scalar argument) has been deemed unsuccessful. It has now been removed;
134 trying to use the feature (or to disable the "experimental::autoderef"
135 warning it previously triggered) now yields an exception.
136 Lexical $_ has been removed
138 "my $_" was introduced in Perl 5.10, and subsequently caused much
139 confusion with no obvious solution. In Perl 5.18.0, it was made
140 experimental on the theory that it would either be removed or
141 redesigned in a less confusing (but backward-incompatible) way. Over
142 the following years, no alternatives were proposed. The feature has
143 now been removed and will fail to compile.
144 "qr/\b{wb}/" is now tailored to Perl expectations
146 This is now more suited to be a drop-in replacement for plain "\b", but
147 giving better results for parsing natural language. Previously it
148 strictly followed the current Unicode rules which calls for it to match
149 between each white space character. Now it doesn't generally match
150 within spans of white space, behaving like "\b" does. See "\b{wb}" in
151 perlrebackslash
152 Regular expression compilation errors
154 Some regular expression patterns that had runtime errors now don't
155 compile at all.
156 Almost all Unicode properties using the "\p{}" and "\P{}" regular
158 expression pattern constructs are now checked for validity at pattern
159 compilation time, and invalid ones will cause the program to not
160 compile. In earlier releases, this check was often deferred until run
161 time. Whenever an error check is moved from run- to compile time,
162 erroneous code is caught 100% of the time, whereas before it would only
163 get caught if and when the offending portion actually gets executed,
164 which for unreachable code might be never.
165 "qr/\N{}/" now disallowed under "use re "strict""
167 An empty "\N{}" makes no sense, but for backwards compatibility is
168 accepted as doing nothing, though a deprecation warning is raised by
169 default. But now this is a fatal error under the experimental feature
170 "'strict' mode" in re.
171 Nested declarations are now disallowed
173 A "my", "our", or "state" declaration is no longer allowed inside of
174 another "my", "our", or "state" declaration.
175 For example, these are now fatal:
177 my ($x, my($y));
179 our (my $x);
180 [perl #125587] <https://rt.perl.org/Ticket/Display.html?id=125587>
182 [perl #121058] <https://rt.perl.org/Ticket/Display.html?id=121058>
184 The "/\C/" character class has been removed.
186 This regular expression character class was deprecated in v5.20.0 and
187 has produced a deprecation warning since v5.22.0. It is now a compile-
188 time error. If you need to examine the individual bytes that make up a
189 UTF8-encoded character, then use "utf8::encode()" on the string (or a
190 copy) first.
191 "chdir('')" no longer chdirs home
193 Using "chdir('')" or "chdir(undef)" to chdir home has been deprecated
194 since perl v5.8, and will now fail. Use "chdir()" instead.
195 ASCII characters in variable names must now be all visible
197 It was legal until now on ASCII platforms for variable names to contain
198 non-graphical ASCII control characters (ordinals 0 through 31, and 127,
199 which are the C0 controls and "DELETE"). This usage has been
200 deprecated since v5.20, and as of now causes a syntax error. The
201 variables these names referred to are special, reserved by Perl for
202 whatever use it may choose, now, or in the future. Each such variable
203 has an alternative way of spelling it. Instead of the single non-
204 graphic control character, a two character sequence beginning with a
205 caret is used, like $^] and "${^GLOBAL_PHASE}". Details are at
206 perlvar. It remains legal, though unwise and deprecated (raising a
207 deprecation warning), to use certain non-graphic non-ASCII characters
208 in variables names when not under "use utf8". No code should do this,
209 as all such variables are reserved by Perl, and Perl doesn't currently
210 define any of them (but could at any time, without notice).
211 An off by one issue in $Carp::MaxArgNums has been fixed
213 $Carp::MaxArgNums is supposed to be the number of arguments to display.
214 Prior to this version, it was instead showing $Carp::MaxArgNums + 1
215 arguments, contrary to the documentation.
216 Only blanks and tabs are now allowed within "[...]" within "(?[...])".
218 The experimental Extended Bracketed Character Classes can contain
219 regular bracketed character classes within them. These differ from
220 regular ones in that white space is generally ignored, unless escaped
221 by preceding it with a backslash. The white space that is ignored is
222 now limited to just tab "\t" and SPACE characters. Previously, it was
223 any white space. See "Extended Bracketed Character Classes" in
224 perlrecharclass.
225
227 Using code points above the platform's "IV_MAX" is now deprecated
228 Unicode defines code points in the range "0..0x10FFFF". Some standards
229 at one time defined them up to 2**31 - 1, but Perl has allowed them to
230 be as high as anything that will fit in a word on the platform being
231 used. However, use of those above the platform's "IV_MAX" is broken in
232 some constructs, notably "tr///", regular expression patterns involving
233 quantifiers, and in some arithmetic and comparison operations, such as
234 being the upper limit of a loop. Now the use of such code points
235 raises a deprecation warning, unless that warning category is turned
236 off. "IV_MAX" is typically 2**31 -1 on 32-bit platforms, and 2**63-1
237 on 64-bit ones.
238 Doing bitwise operations on strings containing code points above 0xFF is
240 deprecated
241 The string bitwise operators treat their operands as strings of bytes,
242 and values beyond 0xFF are nonsensical in this context. To operate on
243 encoded bytes, first encode the strings. To operate on code points'
244 numeric values, use "split" and "map ord". In the future, this warning
245 will be replaced by an exception.
246 "sysread()", "syswrite()", "recv()" and "send()" are deprecated on :utf8
248 handles
249 The "sysread()", "recv()", "syswrite()" and "send()" operators are
250 deprecated on handles that have the ":utf8" layer, either explicitly,
251 or implicitly, eg., with the ":encoding(UTF-16LE)" layer.
252 Both "sysread()" and "recv()" currently use only the ":utf8" flag for
254 the stream, ignoring the actual layers. Since "sysread()" and "recv()"
255 do no UTF-8 validation they can end up creating invalidly encoded
256 scalars.
257 Similarly, "syswrite()" and "send()" use only the ":utf8" flag,
259 otherwise ignoring any layers. If the flag is set, both write the
260 value UTF-8 encoded, even if the layer is some different encoding, such
261 as the example above.
262 Ideally, all of these operators would completely ignore the ":utf8"
264 state, working only with bytes, but this would result in silently
265 breaking existing code. To avoid this a future version of perl will
266 throw an exception when any of "sysread()", "recv()", "syswrite()" or
267 "send()" are called on handle with the ":utf8" layer.
268
270 · The overhead of scope entry and exit has been considerably reduced,
271 so for example subroutine calls, loops and basic blocks are all
272 faster now. This empty function call now takes about a third less
273 time to execute:
274 sub f{} f();
276 · Many languages, such as Chinese, are caseless. Perl now knows
278 about most common ones, and skips much of the work when a program
279 tries to change case in them (like "ucfirst()") or match caselessly
280 ("qr//i"). This will speed up a program, such as a web server,
281 that can operate on multiple languages, while it is operating on a
282 caseless one.
283 · "/fixed-substr/" has been made much faster.
285 On platforms with a libc "memchr()" implementation which makes good
287 use of underlying hardware support, patterns which include fixed
288 substrings will now often be much faster; for example with glibc on
289 a recent x86_64 CPU, this:
290 $s = "a" x 1000 . "wxyz";
292 $s =~ /wxyz/ for 1..30000
293 is now about 7 times faster. On systems with slow "memchr()", e.g.
295 32-bit ARM Raspberry Pi, there will be a small or little speedup.
296 Conversely, some pathological cases, such as ""ab" x 1000 =~ /aa/"
297 will be slower now; up to 3 times slower on the rPi, 1.5x slower on
298 x86_64.
299 · Faster addition, subtraction and multiplication.
301 Since 5.8.0, arithmetic became slower due to the need to support
303 64-bit integers. To deal with 64-bit integers, a lot more corner
304 cases need to be checked, which adds time. We now detect common
305 cases where there is no need to check for those corner cases, and
306 special-case them.
307 · Preincrement, predecrement, postincrement, and postdecrement have
309 been made faster by internally splitting the functions which
310 handled multiple cases into different functions.
311 · Creating Perl debugger data structures (see "Debugger Internals" in
313 perldebguts) for XSUBs and const subs has been removed. This
314 removed one glob/scalar combo for each unique ".c" file that XSUBs
315 and const subs came from. On startup ("perl -e"0"") about half a
316 dozen glob/scalar debugger combos were created. Loading XS modules
317 created more glob/scalar combos. These things were being created
318 regardless of whether the perl debugger was being used, and despite
319 the fact that it can't debug C code anyway
320 · On Win32, "stat"ing or "-X"ing a path, if the file or directory
322 does not exist, is now 3.5x faster than before.
323 · Single arguments in list assign are now slightly faster:
325 ($x) = (...);
327 (...) = ($x);
328 · Less peak memory is now used when compiling regular expression
330 patterns.
331
333 Updated Modules and Pragmata
334 · arybase has been upgraded from version 0.10 to 0.11.
335 · Attribute::Handlers has been upgraded from version 0.97 to 0.99.
337 · autodie has been upgraded from version 2.26 to 2.29.
339 · autouse has been upgraded from version 1.08 to 1.11.
341 · B has been upgraded from version 1.58 to 1.62.
343 · B::Deparse has been upgraded from version 1.35 to 1.37.
345 · base has been upgraded from version 2.22 to 2.23.
347 · Benchmark has been upgraded from version 1.2 to 1.22.
349 · bignum has been upgraded from version 0.39 to 0.42.
351 · bytes has been upgraded from version 1.04 to 1.05.
353 · Carp has been upgraded from version 1.36 to 1.40.
355 · Compress::Raw::Bzip2 has been upgraded from version 2.068 to 2.069.
357 · Compress::Raw::Zlib has been upgraded from version 2.068 to 2.069.
359 · Config::Perl::V has been upgraded from version 0.24 to 0.25.
361 · CPAN::Meta has been upgraded from version 2.150001 to 2.150005.
363 · CPAN::Meta::Requirements has been upgraded from version 2.132 to
365 2.140.
366 · CPAN::Meta::YAML has been upgraded from version 0.012 to 0.018.
368 · Data::Dumper has been upgraded from version 2.158 to 2.160.
370 · Devel::Peek has been upgraded from version 1.22 to 1.23.
372 · Devel::PPPort has been upgraded from version 3.31 to 3.32.
374 · Dumpvalue has been upgraded from version 1.17 to 1.18.
376 · DynaLoader has been upgraded from version 1.32 to 1.38.
378 · Encode has been upgraded from version 2.72 to 2.80.
380 · encoding has been upgraded from version 2.14 to 2.17.
382 · encoding::warnings has been upgraded from version 0.11 to 0.12.
384 · English has been upgraded from version 1.09 to 1.10.
386 · Errno has been upgraded from version 1.23 to 1.25.
388 · experimental has been upgraded from version 0.013 to 0.016.
390 · ExtUtils::CBuilder has been upgraded from version 0.280221 to
392 0.280225.
393 · ExtUtils::Embed has been upgraded from version 1.32 to 1.33.
395 · ExtUtils::MakeMaker has been upgraded from version 7.04_01 to
397 7.10_01.
398 · ExtUtils::ParseXS has been upgraded from version 3.28 to 3.31.
400 · ExtUtils::Typemaps has been upgraded from version 3.28 to 3.31.
402 · feature has been upgraded from version 1.40 to 1.42.
404 · fields has been upgraded from version 2.17 to 2.23.
406 · File::Find has been upgraded from version 1.29 to 1.34.
408 · File::Glob has been upgraded from version 1.24 to 1.26.
410 · File::Path has been upgraded from version 2.09 to 2.12_01.
412 · File::Spec has been upgraded from version 3.56 to 3.63.
414 · Filter::Util::Call has been upgraded from version 1.54 to 1.55.
416 · Getopt::Long has been upgraded from version 2.45 to 2.48.
418 · Hash::Util has been upgraded from version 0.18 to 0.19.
420 · Hash::Util::FieldHash has been upgraded from version 1.15 to 1.19.
422 · HTTP::Tiny has been upgraded from version 0.054 to 0.056.
424 · I18N::Langinfo has been upgraded from version 0.12 to 0.13.
426 · if has been upgraded from version 0.0604 to 0.0606.
428 · IO has been upgraded from version 1.35 to 1.36.
430 · IO-Compress has been upgraded from version 2.068 to 2.069.
432 · IPC::Open3 has been upgraded from version 1.18 to 1.20.
434 · IPC::SysV has been upgraded from version 2.04 to 2.06_01.
436 · List::Util has been upgraded from version 1.41 to 1.42_02.
438 · locale has been upgraded from version 1.06 to 1.08.
440 · Locale::Codes has been upgraded from version 3.34 to 3.37.
442 · Math::BigInt has been upgraded from version 1.9997 to 1.999715.
444 · Math::BigInt::FastCalc has been upgraded from version 0.31 to 0.40.
446 · Math::BigRat has been upgraded from version 0.2608 to 0.260802.
448 · Module::CoreList has been upgraded from version 5.20150520 to
450 5.20160320.
451 · Module::Metadata has been upgraded from version 1.000026 to
453 1.000031.
454 · mro has been upgraded from version 1.17 to 1.18.
456 · ODBM_File has been upgraded from version 1.12 to 1.14.
458 · Opcode has been upgraded from version 1.32 to 1.34.
460 · parent has been upgraded from version 0.232 to 0.234.
462 · Parse::CPAN::Meta has been upgraded from version 1.4414 to 1.4417.
464 · Perl::OSType has been upgraded from version 1.008 to 1.009.
466 · perlfaq has been upgraded from version 5.021009 to 5.021010.
468 · PerlIO::encoding has been upgraded from version 0.21 to 0.24.
470 · PerlIO::mmap has been upgraded from version 0.014 to 0.016.
472 · PerlIO::scalar has been upgraded from version 0.22 to 0.24.
474 · PerlIO::via has been upgraded from version 0.15 to 0.16.
476 · Pod::Functions has been upgraded from version 1.09 to 1.10.
478 · Pod::Perldoc has been upgraded from version 3.25 to 3.25_02.
480 · Pod::Simple has been upgraded from version 3.29 to 3.32.
482 · Pod::Usage has been upgraded from version 1.64 to 1.68.
484 · POSIX has been upgraded from version 1.53 to 1.65.
486 · Scalar::Util has been upgraded from version 1.41 to 1.42_02.
488 · SDBM_File has been upgraded from version 1.13 to 1.14.
490 · SelfLoader has been upgraded from version 1.22 to 1.23.
492 · Socket has been upgraded from version 2.018 to 2.020_03.
494 · Storable has been upgraded from version 2.53 to 2.56.
496 · strict has been upgraded from version 1.09 to 1.11.
498 · Term::ANSIColor has been upgraded from version 4.03 to 4.04.
500 · Term::Cap has been upgraded from version 1.15 to 1.17.
502 · Test has been upgraded from version 1.26 to 1.28.
504 · Test::Harness has been upgraded from version 3.35 to 3.36.
506 · Thread::Queue has been upgraded from version 3.05 to 3.08.
508 · threads has been upgraded from version 2.01 to 2.06.
510 · threads::shared has been upgraded from version 1.48 to 1.50.
512 · Tie::File has been upgraded from version 1.01 to 1.02.
514 · Tie::Scalar has been upgraded from version 1.03 to 1.04.
516 · Time::HiRes has been upgraded from version 1.9726 to 1.9732.
518 · Time::Piece has been upgraded from version 1.29 to 1.31.
520 · Unicode::Collate has been upgraded from version 1.12 to 1.14.
522 · Unicode::Normalize has been upgraded from version 1.18 to 1.25.
524 · Unicode::UCD has been upgraded from version 0.61 to 0.64.
526 · UNIVERSAL has been upgraded from version 1.12 to 1.13.
528 · utf8 has been upgraded from version 1.17 to 1.19.
530 · version has been upgraded from version 0.9909 to 0.9916.
532 · warnings has been upgraded from version 1.32 to 1.36.
534 · Win32 has been upgraded from version 0.51 to 0.52.
536 · Win32API::File has been upgraded from version 0.1202 to 0.1203.
538 · XS::Typemap has been upgraded from version 0.13 to 0.14.
540 · XSLoader has been upgraded from version 0.20 to 0.21.
542
544 Changes to Existing Documentation
545 perlapi
546 · The process of using undocumented globals has been documented,
548 namely, that one should send email to perl5-porters@perl.org
549 <mailto:perl5-porters@perl.org> first to get the go-ahead for
550 documenting and using an undocumented function or global variable.
551 perlcall
553 · A number of cleanups have been made to perlcall, including:
555 · use "EXTEND(SP, n)" and "PUSHs()" instead of "XPUSHs()" where
557 applicable and update prose to match
558 · add POPu, POPul and POPpbytex to the "complete list of POP
560 macros" and clarify the documentation for some of the existing
561 entries, and a note about side-effects
562 · add API documentation for POPu and POPul
564 · use ERRSV more efficiently
566 · approaches to thread-safety storage of SVs.
568 perlfunc
570 · The documentation of "hex" has been revised to clarify valid
572 inputs.
573 · Better explain meaning of negative PIDs in "waitpid". [perl
575 #127080] <https://rt.perl.org/Ticket/Display.html?id=127080>
576 · General cleanup: there's more consistency now (in POD usage,
578 grammar, code examples), better practices in code examples (use of
579 "my", removal of bareword filehandles, dropped usage of "&" when
580 calling subroutines, ...), etc.
581 perlguts
583 · A new section has been added, "Dynamic Scope and the Context Stack"
585 in perlguts, which explains how the perl context stack works.
586 perllocale
588 · A stronger caution about using locales in threaded applications is
590 given. Locales are not thread-safe, and you can get wrong results
591 or even segfaults if you use them there.
592 perlmodlib
594 · We now recommend contacting the module-authors list or PAUSE in
596 seeking guidance on the naming of modules.
597 perlop
599 · The documentation of "qx//" now describes how $? is affected.
601 perlpolicy
603 · This note has been added to perlpolicy:
605 While civility is required, kindness is encouraged; if you have any
607 doubt about whether you are being civil, simply ask yourself, "Am I
608 being kind?" and aspire to that.
609 perlreftut
611 · Fix some examples to be strict clean.
613 perlrebackslash
615 · Clarify that in languages like Japanese and Thai, dictionary lookup
617 is required to determine word boundaries.
618 perlsub
620 · Updated to note that anonymous subroutines can have signatures.
622 perlsyn
624 · Fixed a broken example where "=" was used instead of "==" in
626 conditional in do/while example.
627 perltie
629 · The usage of "FIRSTKEY" and "NEXTKEY" has been clarified.
631 perlunicode
633 · Discourage use of 'In' as a prefix signifying the Unicode Block
635 property.
636 perlvar
638 · The documentation of $@ was reworded to clarify that it is not just
640 for syntax errors in "eval". [perl #124034]
641 <https://rt.perl.org/Ticket/Display.html?id=124034>
642 · The specific true value of $!{E...} is now documented, noting that
644 it is subject to change and not guaranteed.
645 · Use of $OLD_PERL_VERSION is now discouraged.
647 perlxs
649 · The documentation of "PROTOTYPES" has been corrected; they are
651 disabled by default, not enabled.
652
654 The following additions or changes have been made to diagnostic output,
655 including warnings and fatal error messages. For the complete list of
656 diagnostic messages, see perldiag.
657 New Diagnostics
659 New Errors
660 · %s must not be a named sequence in transliteration operator
662 · Can't find Unicode property definition "%s" in regex;
664 · Can't redeclare "%s" in "%s"
666 · Character following \p must be '{' or a single-character Unicode
668 property name in regex;
669 · Empty \%c in regex; marked by <-- HERE in m/%s/
671 · Illegal user-defined property name
673 · Invalid number '%s' for -C option.
675 · Sequence (?... not terminated in regex; marked by <-- HERE in m/%s/
677 · Sequence (?P<... not terminated in regex; marked by <-- HERE in
679 m/%s/
680 · Sequence (?P>... not terminated in regex; marked by <-- HERE in
682 m/%s/
683 New Warnings
685 · Assuming NOT a POSIX class since %s in regex; marked by <-- HERE in
687 m/%s/
688 · %s() is deprecated on :utf8 handles
690 Changes to Existing Diagnostics
692 · Accessing the "IO" part of a glob as "FILEHANDLE" instead of "IO"
693 is no longer deprecated. It is discouraged to encourage uniformity
694 (so that, for example, one can grep more easily) but it will not be
695 removed. [perl #127060]
696 <https://rt.perl.org/Ticket/Display.html?id=127060>
697 · The diagnostic "Hexadecimal float: internal error" has been changed
699 to "Hexadecimal float: internal error (%s)" to include more
700 information.
701 · Can't modify non-lvalue subroutine call of &%s
703 This error now reports the name of the non-lvalue subroutine you
705 attempted to use as an lvalue.
706 · When running out of memory during an attempt the increase the stack
708 size, previously, perl would die using the cryptic message "panic:
709 av_extend_guts() negative count (-9223372036854775681)". This has
710 been fixed to show the prettier message: Out of memory during stack
711 extend
712
714 · "Configure" now acts as if the "-O" option is always passed,
715 allowing command line options to override saved configuration.
716 This should eliminate confusion when command line options are
717 ignored for no obvious reason. "-O" is now permitted, but ignored.
718 · Bison 3.0 is now supported.
720 · Configure no longer probes for libnm by default. Originally this
722 was the "New Math" library, but the name has been re-used by the
723 GNOME NetworkManager. [perl #127131]
724 <https://rt.perl.org/Ticket/Display.html?id=127131>
725 · Added Configure probes for "newlocale", "freelocale", and
727 "uselocale".
728 · "PPPort.so/PPPort.dll" no longer get installed, as they are not
730 used by "PPPort.pm", only by its test files.
731 · It is now possible to specify which compilation date to show on
733 "perl -V" output, by setting the macro "PERL_BUILD_DATE".
734 · Using the "NO_HASH_SEED" define in combination with the default
736 hash algorithm "PERL_HASH_FUNC_ONE_AT_A_TIME_HARD" resulted in a
737 fatal error while compiling the interpreter, since Perl 5.17.10.
738 This has been fixed.
739 · Configure should handle spaces in paths a little better.
741 · No longer generate EBCDIC POSIX-BC tables. We don't believe anyone
743 is using Perl and POSIX-BC at this time, and by not generating
744 these tables it saves time during development, and makes the
745 resulting tar ball smaller.
746 · The GNU Make makefile for Win32 now supports parallel builds.
748 [perl #126632]
749 · You can now build perl with MSVC++ on Win32 using GNU Make. [perl
751 #126632]
752 · The Win32 miniperl now has a real "getcwd" which increases build
754 performance resulting in "getcwd()" being 605x faster in Win32
755 miniperl.
756 · Configure now takes "-Dusequadmath" into account when calculating
758 the "alignbytes" configuration variable. Previously the mis-
759 calculated "alignbytes" could cause alignment errors on debugging
760 builds. [perl #127894]
761
763 · A new test (t/op/aassign.t) has been added to test the list
764 assignment operator "OP_AASSIGN".
765 · Parallel building has been added to the dmake "makefile.mk"
767 makefile. All Win32 compilers are supported.
768
770 Platform-Specific Notes
771 AmigaOS
772 · The AmigaOS port has been reintegrated into the main tree,
773 based off of Perl 5.22.1.
774 Cygwin
776 · Tests are more robust against unusual cygdrive prefixes. [perl
777 #126834] <https://rt.perl.org/Ticket/Display.html?id=126834>
778 EBCDIC
780 UTF-EBCDIC extended
781 UTF-EBCDIC is like UTF-8, but for EBCDIC platforms. It now has
782 been extended so that it can represent code points up to 2 **
783 64 - 1 on platforms with 64-bit words. This brings it into
784 parity with UTF-8. This enhancement requires an incompatible
785 change to the representation of code points in the range 2 **
786 30 to 2 ** 31 -1 (the latter was the previous maximum
787 representable code point). This means that a file that
788 contains one of these code points, written out with previous
789 versions of perl cannot be read in, without conversion, by a
790 perl containing this change. We do not believe any such files
791 are in existence, but if you do have one, submit a ticket at
792 perlbug@perl.org <mailto:perlbug@perl.org>, and we will write a
793 conversion script for you.
794 EBCDIC "cmp()" and "sort()" fixed for UTF-EBCDIC strings
796 Comparing two strings that were both encoded in UTF-8 (or more
797 precisely, UTF-EBCDIC) did not work properly until now. Since
798 "sort()" uses "cmp()", this fixes that as well.
799 EBCDIC "tr///" and "y///" fixed for "\N{}", and "use utf8" ranges
801 Perl v5.22 introduced the concept of portable ranges to regular
802 expression patterns. A portable range matches the same set of
803 characters no matter what platform is being run on. This
804 concept is now extended to "tr///". See "tr///".
805 There were also some problems with these operations under
807 "use utf8", which are now fixed
808 FreeBSD
810 · Use the "fdclose()" function from FreeBSD if it is available.
811 [perl #126847]
812 <https://rt.perl.org/Ticket/Display.html?id=126847>
813 IRIX
815 · Under some circumstances IRIX stdio "fgetc()" and "fread()" set
816 the errno to "ENOENT", which made no sense according to either
817 IRIX or POSIX docs. Errno is now cleared in such cases. [perl
818 #123977] <https://rt.perl.org/Ticket/Display.html?id=123977>
819 · Problems when multiplying long doubles by infinity have been
821 fixed. [perl #126396]
822 <https://rt.perl.org/Ticket/Display.html?id=126396>
823 MacOS X
825 · Until now OS X builds of perl have specified a link target of
826 10.3 (Panther, 2003) but have not specified a compiler target.
827 From now on, builds of perl on OS X 10.6 or later (Snow
828 Leopard, 2008) by default capture the current OS X version and
829 specify that as the explicit build target in both compiler and
830 linker flags, thus preserving binary compatibility for
831 extensions built later regardless of changes in OS X, SDK, or
832 compiler and linker versions. To override the default value
833 used in the build and preserved in the flags, specify "export
834 MACOSX_DEPLOYMENT_TARGET=10.N" before configuring and building
835 perl, where 10.N is the version of OS X you wish to target. In
836 OS X 10.5 or earlier there is no change to the behavior present
837 when those systems were current; the link target is still OS X
838 10.3 and there is no explicit compiler target.
839 · Builds with both -DDEBUGGING and threading enabled would fail
841 with a "panic: free from wrong pool" error when built or tested
842 from Terminal on OS X. This was caused by perl's internal
843 management of the environment conflicting with an atfork
844 handler using the libc "setenv()" function to update the
845 environment.
846 Perl now uses "setenv()"/"unsetenv()" to update the environment
848 on OS X. [perl #126240]
849 <https://rt.perl.org/Ticket/Display.html?id=126240>
850 Solaris
852 · All Solaris variants now build a shared libperl
853 Solaris and variants like OpenIndiana now always build with the
855 shared Perl library (Configure -Duseshrplib). This was
856 required for the OpenIndiana builds, but this has also been the
857 setting for Oracle/Sun Perl builds for several years.
858 Tru64
860 · Workaround where Tru64 balks when prototypes are listed as
861 "PERL_STATIC_INLINE", but where the test is build with
862 "-DPERL_NO_INLINE_FUNCTIONS".
863 VMS
865 · On VMS, the math function prototypes in "math.h" are now
866 visible under C++. Now building the POSIX extension with C++
867 will no longer crash.
868 · VMS has had "setenv"/"unsetenv" since v7.0 (released in 1996),
870 "Perl_vmssetenv" now always uses "setenv"/"unsetenv".
871 · Perl now implements its own "killpg" by scanning for processes
873 in the specified process group, which may not mean exactly the
874 same thing as a Unix process group, but allows us to send a
875 signal to a parent (or master) process and all of its sub-
876 processes. At the perl level, this means we can now send a
877 negative pid like so:
878 kill SIGKILL, -$pid;
880 to signal all processes in the same group as $pid.
882 · For those %ENV elements based on the CRTL environ array, we've
884 always preserved case when setting them but did look-ups only
885 after upcasing the key first, which made lower- or mixed-case
886 entries go missing. This problem has been corrected by making
887 %ENV elements derived from the environ array case-sensitive on
888 look-up as well as case-preserving on store.
889 · Environment look-ups for "PERL5LIB" and "PERLLIB" previously
891 only considered logical names, but now consider all sources of
892 %ENV as determined by "PERL_ENV_TABLES" and as documented in
893 "%ENV" in perlvms.
894 · The minimum supported version of VMS is now v7.3-2, released in
896 2003. As a side effect of this change, VAX is no longer
897 supported as the terminal release of OpenVMS VAX was v7.3 in
898 2001.
899 Win32
901 · A new build option "USE_NO_REGISTRY" has been added to the
902 makefiles. This option is off by default, meaning the default
903 is to do Windows registry lookups. This option stops Perl from
904 looking inside the registry for anything. For what values are
905 looked up in the registry see perlwin32. Internally, in C, the
906 name of this option is "WIN32_NO_REGISTRY".
907 · The behavior of Perl using "HKEY_CURRENT_USER\Software\Perl"
909 and "HKEY_LOCAL_MACHINE\Software\Perl" to lookup certain
910 values, including %ENV vars starting with "PERL" has changed.
911 Previously, the 2 keys were checked for entries at all times
912 through the perl process's life time even if they did not
913 exist. For performance reasons, now, if the root key (i.e.
914 "HKEY_CURRENT_USER\Software\Perl" or
915 "HKEY_LOCAL_MACHINE\Software\Perl") does not exist at process
916 start time, it will not be checked again for %ENV override
917 entries for the remainder of the perl process's life. This
918 more closely matches Unix behavior in that the environment is
919 copied or inherited on startup and changing the variable in the
920 parent process or another process or editing .bashrc will not
921 change the environmental variable in other existing, running,
922 processes.
923 · One glob fetch was removed for each "-X" or "stat" call whether
925 done from Perl code or internally from Perl's C code. The glob
926 being looked up was "${^WIN32_SLOPPY_STAT}" which is a special
927 variable. This makes "-X" and "stat" slightly faster.
928 · During miniperl's process startup, during the build process, 4
930 to 8 IO calls related to the process starting .pl and the
931 buildcustomize.pl file were removed from the code opening and
932 executing the first 1 or 2 .pl files.
933 · Builds using Microsoft Visual C++ 2003 and earlier no longer
935 produce an "INTERNAL COMPILER ERROR" message. [perl #126045]
936 · Visual C++ 2013 builds will now execute on XP and higher.
938 Previously they would only execute on Vista and higher.
939 · You can now build perl with GNU Make and GCC. [perl #123440]
941 · "truncate($filename, $size)" now works for files over 4GB in
943 size. [perl #125347]
944 · Parallel building has been added to the dmake "makefile.mk"
946 makefile. All Win32 compilers are supported.
947 · Building a 64-bit perl with a 64-bit GCC but a 32-bit gmake
949 would result in an invalid $Config{archname} for the resulting
950 perl. [perl #127584]
951 · Errors set by Winsock functions are now put directly into $^E,
953 and the relevant "WSAE*" error codes are now exported from the
954 Errno and POSIX modules for testing this against.
955 The previous behavior of putting the errors (converted to
957 POSIX-style "E*" error codes since Perl 5.20.0) into $! was
958 buggy due to the non-equivalence of like-named Winsock and
959 POSIX error constants, a relationship between which has
960 unfortunately been established in one way or another since Perl
961 5.8.0.
962 The new behavior provides a much more robust solution for
964 checking Winsock errors in portable software without
965 accidentally matching POSIX tests that were intended for other
966 OSes and may have different meanings for Winsock.
967 The old behavior is currently retained, warts and all, for
969 backwards compatibility, but users are encouraged to change any
970 code that tests $! against "E*" constants for Winsock errors
971 to instead test $^E against "WSAE*" constants. After a
972 suitable deprecation period, the old behavior may be removed,
973 leaving $! unchanged after Winsock function calls, to avoid any
974 possible confusion over which error variable to check.
975 ppc64el
977 floating point
978 The floating point format of ppc64el (Debian naming for little-
979 endian PowerPC) is now detected correctly.
980
982 · The implementation of perl's context stack system, and its internal
983 API, have been heavily reworked. Note that no significant changes
984 have been made to any external APIs, but XS code which relies on
985 such internal details may need to be fixed. The main changes are:
986 · The "PUSHBLOCK()", "POPSUB()" etc. macros have been replaced
988 with static inline functions such as "cx_pushblock()",
989 "cx_popsub()" etc. These use function args rather than
990 implicitly relying on local vars such as "gimme" and "newsp"
991 being available. Also their functionality has changed: in
992 particular, "cx_popblock()" no longer decrements "cxstack_ix".
993 The ordering of the steps in the "pp_leave*" functions
994 involving "cx_popblock()", "cx_popsub()" etc. has changed. See
995 the new documentation, "Dynamic Scope and the Context Stack" in
996 perlguts, for details on how to use them.
997 · Various macros, which now consistently have a CX_ prefix, have
999 been added:
1000 CX_CUR(), CX_LEAVE_SCOPE(), CX_POP()
1002 or renamed:
1004 CX_POP_SAVEARRAY(), CX_DEBUG(), CX_PUSHSUBST(), CX_POPSUBST()
1006 · "cx_pushblock()" now saves "PL_savestack_ix" and
1008 "PL_tmps_floor", so "pp_enter*" and "pp_leave*" no longer do
1009 ENTER; SAVETMPS; ....; LEAVE
1011 · "cx_popblock()" now also restores "PL_curpm".
1013 · In "dounwind()" for every context type, the current savestack
1015 frame is now processed before each context is popped; formerly
1016 this was only done for sub-like context frames. This action has
1017 been removed from "cx_popsub()" and placed into its own macro,
1018 "CX_LEAVE_SCOPE(cx)", which must be called before "cx_popsub()"
1019 etc.
1020 "dounwind()" now also does a "cx_popblock()" on the last popped
1022 frame (formerly it only did the "cx_popsub()" etc. actions on
1023 each frame).
1024 · The temps stack is now freed on scope exit; previously, temps
1026 created during the last statement of a block wouldn't be freed
1027 until the next "nextstate" following the block (apart from an
1028 existing hack that did this for recursive subs in scalar
1029 context); and in something like "f(g())", the temps created by
1030 the last statement in "g()" would formerly not be freed until
1031 the statement following the return from "f()".
1032 · Most values that were saved on the savestack on scope entry are
1034 now saved in suitable new fields in the context struct, and
1035 saved and restored directly by "cx_pushfoo()" and
1036 "cx_popfoo()", which is much faster.
1037 · Various context struct fields have been added, removed or
1039 modified.
1040 · The handling of @_ in "cx_pushsub()" and "cx_popsub()" has been
1042 considerably tidied up, including removing the "argarray" field
1043 from the context struct, and extracting out some common (but
1044 rarely used) code into a separate function, "clear_defarray()".
1045 Also, useful subsets of "cx_popsub()" which had been unrolled
1046 in places like "pp_goto" have been gathered into the new
1047 functions "cx_popsub_args()" and "cx_popsub_common()".
1048 · "pp_leavesub" and "pp_leavesublv" now use the same function as
1050 the rest of the "pp_leave*"'s to process return args.
1051 · "CXp_FOR_PAD" and "CXp_FOR_GV" flags have been added, and
1053 "CXt_LOOP_FOR" has been split into "CXt_LOOP_LIST",
1054 "CXt_LOOP_ARY".
1055 · Some variables formerly declared by "dMULTICALL" (but not
1057 documented) have been removed.
1058 · The obscure "PL_timesbuf" variable, effectively a vestige of Perl
1060 1, has been removed. It was documented as deprecated in Perl 5.20,
1061 with a statement that it would be removed early in the 5.21.x
1062 series; that has now finally happened. [perl #121351]
1063 <https://rt.perl.org/Ticket/Display.html?id=121351>
1064 · An unwarranted assertion in "Perl_newATTRSUB_x()" has been removed.
1066 If a stub subroutine definition with a prototype has been seen,
1067 then any subsequent stub (or definition) of the same subroutine
1068 with an attribute was causing an assertion failure because of a
1069 null pointer. [perl #126845]
1070 <https://rt.perl.org/Ticket/Display.html?id=126845>
1071 · "::" has been replaced by "__" in "ExtUtils::ParseXS", like it's
1073 done for parameters/return values. This is more consistent, and
1074 simplifies writing XS code wrapping C++ classes into a nested Perl
1075 namespace (it requires only a typedef for "Foo__Bar" rather than
1076 two, one for "Foo_Bar" and the other for "Foo::Bar").
1077 · The "to_utf8_case()" function is now deprecated. Instead use
1079 "toUPPER_utf8", "toTITLE_utf8", "toLOWER_utf8", and "toFOLD_utf8".
1080 (See <http://nntp.perl.org/group/perl.perl5.porters/233287>.)
1081 · Perl core code and the threads extension have been annotated so
1083 that, if Perl is configured to use threads, then during compile-
1084 time clang (3.6 or later) will warn about suspicious uses of
1085 mutexes. See
1086 <http://clang.llvm.org/docs/ThreadSafetyAnalysis.html> for more
1087 information.
1088 · The "signbit()" emulation has been enhanced. This will help older
1090 and/or more exotic platforms or configurations.
1091 · Most EBCDIC-specific code in the core has been unified with non-
1093 EBCDIC code, to avoid repetition and make maintenance easier.
1094 · MSWin32 code for $^X has been moved out of the win32 directory to
1096 caretx.c, where other operating systems set that variable.
1097 · "sv_ref()" is now part of the API.
1099 · "sv_backoff" in perlapi had its return type changed from "int" to
1101 "void". It previously has always returned 0 since Perl 5.000
1102 stable but that was undocumented. Although "sv_backoff" is marked
1103 as public API, XS code is not expected to be impacted since the
1104 proper API call would be through public API "sv_setsv(sv,
1105 &PL_sv_undef)", or quasi-public "SvOOK_off", or non-public
1106 "SvOK_off" calls, and the return value of "sv_backoff" was
1107 previously a meaningless constant that can be rewritten as
1108 "(sv_backoff(sv),0)".
1109 · The "EXTEND" and "MEXTEND" macros have been improved to avoid
1111 various issues with integer truncation and wrapping. In
1112 particular, some casts formerly used within the macros have been
1113 removed. This means for example that passing an unsigned "nitems"
1114 argument is likely to raise a compiler warning now (it's always
1115 been documented to require a signed value; formerly int, lately
1116 SSize_t).
1117 · "PL_sawalias" and "GPf_ALIASED_SV" have been removed.
1119 · "GvASSIGN_GENERATION" and "GvASSIGN_GENERATION_set" have been
1121 removed.
1122
1124 · It now works properly to specify a user-defined property, such as
1125 qr/\p{mypkg1::IsMyProperty}/i
1127 with "/i" caseless matching, an explicit package name, and
1129 IsMyProperty not defined at the time of the pattern compilation.
1130 · Perl's "memcpy()", "memmove()", "memset()" and "memcmp()" fallbacks
1132 are now more compatible with the originals. [perl #127619]
1133 · Fixed the issue where a "s///r") with -DPERL_NO_COW attempts to
1135 modify the source SV, resulting in the program dying. [perl
1136 #127635]
1137 · Fixed an EBCDIC-platform-only case where a pattern could fail to
1139 match. This occurred when matching characters from the set of C1
1140 controls when the target matched string was in UTF-8.
1141 · Narrow the filename check in strict.pm and warnings.pm. Previously,
1143 it assumed that if the filename (without the .pmc? extension)
1144 differed from the package name, if was a misspelled use statement
1145 (i.e. "use Strict" instead of "use strict"). We now check whether
1146 there's really a miscapitalization happening, and not some other
1147 issue.
1148 · Turn an assertion into a more user friendly failure when parsing
1150 regexes. [perl #127599]
1151 · Correctly raise an error when trying to compile patterns with
1153 unterminated character classes while there are trailing
1154 backslashes. [perl #126141].
1155 · Line numbers larger than 2**31-1 but less than 2**32 are no longer
1157 returned by "caller()" as negative numbers. [perl #126991]
1158 · "unless ( assignment )" now properly warns when syntax warnings are
1160 enabled. [perl #127122]
1161 · Setting an "ISA" glob to an array reference now properly adds
1163 "isaelem" magic to any existing elements. Previously modifying
1164 such an element would not update the ISA cache, so method calls
1165 would call the wrong function. Perl would also crash if the "ISA"
1166 glob was destroyed, since new code added in 5.23.7 would try to
1167 release the "isaelem" magic from the elements. [perl #127351]
1168 · If a here-doc was found while parsing another operator, the parser
1170 had already read end of file, and the here-doc was not terminated,
1171 perl could produce an assertion or a segmentation fault. This now
1172 reliably complains about the unterminated here-doc. [perl #125540]
1173 · "untie()" would sometimes return the last value returned by the
1175 "UNTIE()" handler as well as it's normal value, messing up the
1176 stack. [perl #126621]
1177 · Fixed an operator precedence problem when " castflags & 2" is true.
1179 [perl #127474]
1180 · Caching of DESTROY methods could result in a non-pointer or a non-
1182 STASH stored in the "SvSTASH()" slot of a stash, breaking the B
1183 "STASH()" method. The DESTROY method is now cached in the MRO
1184 metadata for the stash. [perl #126410]
1185 · The AUTOLOAD method is now called when searching for a DESTROY
1187 method, and correctly sets $AUTOLOAD too. [perl #124387] [perl
1188 #127494]
1189 · Avoid parsing beyond the end of the buffer when processing a
1191 "#line" directive with no filename. [perl #127334]
1192 · Perl now raises a warning when a regular expression pattern looks
1194 like it was supposed to contain a POSIX class, like
1195 "qr/[[:alpha:]]/", but there was some slight defect in its
1196 specification which causes it to instead be treated as a regular
1197 bracketed character class. An example would be missing the second
1198 colon in the above like this: "qr/[[:alpha]]/". This compiles to
1199 match a sequence of two characters. The second is "]", and the
1200 first is any of: "[", ":", "a", "h", "l", or "p". This is
1201 unlikely to be the intended meaning, and now a warning is raised.
1202 No warning is raised unless the specification is very close to one
1203 of the 14 legal POSIX classes. (See "POSIX Character Classes" in
1204 perlrecharclass.) [perl #8904]
1205 · Certain regex patterns involving a complemented POSIX class in an
1207 inverted bracketed character class, and matching something else
1208 optionally would improperly fail to match. An example of one that
1209 could fail is "qr/_?[^\Wbar]\x{100}/". This has been fixed. [perl
1210 #127537]
1211 · Perl 5.22 added support to the C99 hexadecimal floating point
1213 notation, but sometimes misparses hex floats. This has been fixed.
1214 [perl #127183]
1215 · A regression that allowed undeclared barewords in hash keys to work
1217 despite strictures has been fixed. [perl #126981]
1218 <https://rt.perl.org/Ticket/Display.html?id=126981>
1219 · Calls to the placeholder &PL_sv_yes used internally when an
1221 "import()" or "unimport()" method isn't found now correctly handle
1222 scalar context. [perl #126042]
1223 <https://rt.perl.org/Ticket/Display.html?id=126042>
1224 · Report more context when we see an array where we expect to see an
1226 operator and avoid an assertion failure. [perl #123737]
1227 <https://rt.perl.org/Ticket/Display.html?id=123737>
1228 · Modifying an array that was previously a package @ISA no longer
1230 causes assertion failures or crashes. [perl #123788]
1231 <https://rt.perl.org/Ticket/Display.html?id=123788>
1232 · Retain binary compatibility across plain and DEBUGGING perl builds.
1234 [perl #127212] <https://rt.perl.org/Ticket/Display.html?id=127212>
1235 · Avoid leaking memory when setting $ENV{foo} on darwin. [perl
1237 #126240] <https://rt.perl.org/Ticket/Display.html?id=126240>
1238 · "/...\G/" no longer crashes on utf8 strings. When "\G" is a fixed
1240 number of characters from the start of the regex, perl needs to
1241 count back that many characters from the current "pos()" position
1242 and start matching from there. However, it was counting back bytes
1243 rather than characters, which could lead to panics on utf8 strings.
1244 · In some cases operators that return integers would return negative
1246 integers as large positive integers. [perl #126635]
1247 <https://rt.perl.org/Ticket/Display.html?id=126635>
1248 · The "pipe()" operator would assert for DEBUGGING builds instead of
1250 producing the correct error message. The condition asserted on is
1251 detected and reported on correctly without the assertions, so the
1252 assertions were removed. [perl #126480]
1253 <https://rt.perl.org/Ticket/Display.html?id=126480>
1254 · In some cases, failing to parse a here-doc would attempt to use
1256 freed memory. This was caused by a pointer not being restored
1257 correctly. [perl #126443]
1258 <https://rt.perl.org/Ticket/Display.html?id=126443>
1259 · "@x = sort { *a = 0; $a <=> $b } 0 .. 1" no longer frees the GP for
1261 *a before restoring its SV slot. [perl #124097]
1262 <https://rt.perl.org/Ticket/Display.html?id=124097>
1263 · Multiple problems with the new hexadecimal floating point printf
1265 format %a were fixed: [perl #126582]
1266 <https://rt.perl.org/Ticket/Display.html?id=126582>, [perl #126586]
1267 <https://rt.perl.org/Ticket/Display.html?id=126586>, [perl #126822]
1268 <https://rt.perl.org/Ticket/Display.html?id=126822>
1269 · Calling "mg_set()" in "leave_scope()" no longer leaks.
1271 · A regression from Perl v5.20 was fixed in which debugging output of
1273 regular expression compilation was wrong. (The pattern was
1274 correctly compiled, but what got displayed for it was wrong.)
1275 · "\b{sb}" works much better. In Perl v5.22.0, this new construct
1277 didn't seem to give the expected results, yet passed all the tests
1278 in the extensive suite furnished by Unicode. It turns out that it
1279 was because these were short input strings, and the failures had to
1280 do with longer inputs.
1281 · Certain syntax errors in "Extended Bracketed Character Classes" in
1283 perlrecharclass caused panics instead of the proper error message.
1284 This has now been fixed. [perl #126481]
1285 · Perl 5.20 added a message when a quantifier in a regular expression
1287 was useless, but then caused the parser to skip it; this caused the
1288 surplus quantifier to be silently ignored, instead of throwing an
1289 error. This is now fixed. [perl #126253]
1290 · The switch to building non-XS modules last in win32/makefile.mk
1292 (introduced by design as part of the changes to enable parallel
1293 building) caused the build of POSIX to break due to problems with
1294 the version module. This is now fixed.
1295 · Improved parsing of hex float constants.
1297 · Fixed an issue with "pack" where "pack "H"" (and "pack "h"") could
1299 read past the source when given a non-utf8 source, and a utf8
1300 target. [perl #126325]
1301 · Fixed several cases where perl would abort due to a segmentation
1303 fault, or a C-level assert. [perl #126615], [perl #126602], [perl
1304 #126193].
1305 · There were places in regular expression patterns where comments
1307 ("(?#...)") weren't allowed, but should have been. This is now
1308 fixed. [perl #116639]
1309 <https://rt.perl.org/Ticket/Display.html?id=116639>
1310 · Some regressions from Perl 5.20 have been fixed, in which some
1312 syntax errors in "(?[...])" constructs within regular expression
1313 patterns could cause a segfault instead of a proper error message.
1314 [perl #126180] <https://rt.perl.org/Ticket/Display.html?id=126180>
1315 [perl #126404] <https://rt.perl.org/Ticket/Display.html?id=126404>
1316 · Another problem with "(?[...])" constructs has been fixed wherein
1318 things like "\c]" could cause panics. [perl #126181]
1319 <https://rt.perl.org/Ticket/Display.html?id=126181>
1320 · Some problems with attempting to extend the perl stack to around 2G
1322 or 4G entries have been fixed. This was particularly an issue on
1323 32-bit perls built to use 64-bit integers, and was easily
1324 noticeable with the list repetition operator, e.g.
1325 @a = (1) x $big_number
1327 Formerly perl may have crashed, depending on the exact value of
1329 $big_number; now it will typically raise an exception. [perl
1330 #125937] <https://rt.perl.org/Ticket/Display.html?id=125937>
1331 · In a regex conditional expression
1333 "(?(condition)yes-pattern|no-pattern)", if the condition is "(?!)"
1334 then perl failed the match outright instead of matching the no-
1335 pattern. This has been fixed. [perl #126222]
1336 <https://rt.perl.org/Ticket/Display.html?id=126222>
1337 · The special backtracking control verbs "(*VERB:ARG)" now all allow
1339 an optional argument and set "REGERROR"/"REGMARK" appropriately as
1340 well. [perl #126186]
1341 <https://rt.perl.org/Ticket/Display.html?id=126186>
1342 · Several bugs, including a segmentation fault, have been fixed with
1344 the boundary checking constructs (introduced in Perl 5.22)
1345 "\b{gcb}", "\b{sb}", "\b{wb}", "\B{gcb}", "\B{sb}", and "\B{wb}".
1346 All the "\B{}" ones now match an empty string; none of the "\b{}"
1347 ones do. [perl #126319]
1348 <https://rt.perl.org/Ticket/Display.html?id=126319>
1349 · Duplicating a closed file handle for write no longer creates a
1351 filename of the form GLOB(0xXXXXXXXX). [perl #125115]
1352 · Warning fatality is now ignored when rewinding the stack. This
1354 prevents infinite recursion when the now fatal error also causes
1355 rewinding of the stack. [perl #123398]
1356 · In perl v5.22.0, the logic changed when parsing a numeric parameter
1358 to the -C option, such that the successfully parsed number was not
1359 saved as the option value if it parsed to the end of the argument.
1360 [perl #125381]
1361 · The PadlistNAMES macro is an lvalue again.
1363 · Zero -DPERL_TRACE_OPS memory for sub-threads.
1365 "perl_clone_using()" was missing Zero init of PL_op_exec_cnt[].
1367 This caused sub-threads in threaded -DPERL_TRACE_OPS builds to spew
1368 exceedingly large op-counts at destruct. These counts would print
1369 %x as "ABABABAB", clearly a mem-poison value.
1370 · A leak in the XS typemap caused one scalar to be leaked each time a
1372 "FILE *" or a "PerlIO *" was "OUTPUT:"ed or imported to Perl, since
1373 perl 5.000. These particular typemap entries are thought to be
1374 extremely rarely used by XS modules. [perl #124181]
1375 · "alarm()" and "sleep()" will now warn if the argument is a negative
1377 number and return undef. Previously they would pass the negative
1378 value to the underlying C function which may have set up a timer
1379 with a surprising value.
1380 · Perl can again be compiled with any Unicode version. This used to
1382 (mostly) work, but was lost in v5.18 through v5.20. The property
1383 "Name_Alias" did not exist prior to Unicode 5.0. Unicode::UCD
1384 incorrectly said it did. This has been fixed.
1385 · Very large code-points (beyond Unicode) in regular expressions no
1387 longer cause a buffer overflow in some cases when converted to
1388 UTF-8. [perl #125826]
1389 <https://rt.perl.org/Ticket/Display.html?id=125826>
1390 · The integer overflow check for the range operator (...) in list
1392 context now correctly handles the case where the size of the range
1393 is larger than the address space. This could happen on 32-bits
1394 with -Duse64bitint. [perl #125781]
1395 <https://rt.perl.org/Ticket/Display.html?id=125781>
1396 · A crash with "%::=(); J->${\"::"}" has been fixed. [perl #125541]
1398 <https://rt.perl.org/Ticket/Display.html?id=125541>
1399 · "qr/(?[ () ])/" no longer segfaults, giving a syntax error message
1401 instead. [perl #125805]
1402 · Regular expression possessive quantifier v5.20 regression now
1404 fixed. "qr/"PAT"{"min,max"}+""/" is supposed to behave identically
1405 to "qr/(?>"PAT"{"min,max"})/". Since v5.20, this didn't work if
1406 min and max were equal. [perl #125825]
1407 · "BEGIN <>" no longer segfaults and properly produces an error
1409 message. [perl #125341]
1410 · In "tr///" an illegal backwards range like "tr/\x{101}-\x{100}//"
1412 was not always detected, giving incorrect results. This is now
1413 fixed.
1414
1416 Perl 5.24.0 represents approximately 11 months of development since
1417 Perl 5.24.0 and contains approximately 360,000 lines of changes across
1418 1,800 files from 75 authors.
1419 Excluding auto-generated files, documentation and release tools, there
1421 were approximately 250,000 lines of changes to 1,200 .pm, .t, .c and .h
1422 files.
1423 Perl continues to flourish into its third decade thanks to a vibrant
1425 community of users and developers. The following people are known to
1426 have contributed the improvements that became Perl 5.24.0:
1427 Aaron Crane, Aaron Priven, Abigail, Achim Gratz, Alexander D'Archangel,
1429 Alex Vandiver, Andreas Koenig, Andy Broad, Andy Dougherty, Aristotle
1430 Pagaltzis, Chase Whitener, Chas. Owens, Chris 'BinGOs' Williams, Craig
1431 A. Berry, Dagfinn Ilmari Mannsaaker, Dan Collins, Daniel Dragan, David
1432 Golden, David Mitchell, Doug Bell, Dr.Ruud, Ed Avis, Ed J, Father
1433 Chrysostomos, Herbert Breunung, H.Merijn Brand, Hugo van der Sanden,
1434 Ivan Pozdeev, James E Keenan, Jan Dubois, Jarkko Hietaniemi, Jerry D.
1435 Hedden, Jim Cromie, John Peacock, John SJ Anderson, Karen Etheridge,
1436 Karl Williamson, kmx, Leon Timmermans, Ludovic E. R. Tolhurst-Cleaver,
1437 Lukas Mai, Martijn Lievaart, Matthew Horsfall, Mattia Barbon, Max
1438 Maischein, Mohammed El-Afifi, Nicholas Clark, Nicolas R., Niko Tyni,
1439 Peter John Acklam, Peter Martini, Peter Rabbitson, Pip Cet, Rafael
1440 Garcia-Suarez, Reini Urban, Ricardo Signes, Sawyer X, Shlomi Fish,
1441 Sisyphus, Stanislaw Pusep, Steffen Mueller, Stevan Little, Steve Hay,
1442 Sullivan Beck, Thomas Sibley, Todd Rinaldo, Tom Hukins, Tony Cook,
1443 Unicode Consortium, Victor Adam, Vincent Pit, Vladimir Timofeev, Yves
1444 Orton, Zachary Storer, Zefram.
1445 The list above is almost certainly incomplete as it is automatically
1447 generated from version control history. In particular, it does not
1448 include the names of the (very much appreciated) contributors who
1449 reported issues to the Perl bug tracker.
1450 Many of the changes included in this version originated in the CPAN
1452 modules included in Perl's core. We're grateful to the entire CPAN
1453 community for helping Perl to flourish.
1454 For a more complete list of all of Perl's historical contributors,
1456 please see the AUTHORS file in the Perl source distribution.
1457
1459 If you find what you think is a bug, you might check the articles
1460 recently posted to the comp.lang.perl.misc newsgroup and the perl bug
1461 database at https://rt.perl.org/ . There may also be information at
1462 http://www.perl.org/ , the Perl Home Page.
1463 If you believe you have an unreported bug, please run the perlbug
1465 program included with your release. Be sure to trim your bug down to a
1466 tiny but sufficient test case. Your bug report, along with the output
1467 of "perl -V", will be sent off to perlbug@perl.org to be analysed by
1468 the Perl porting team.
1469 If the bug you are reporting has security implications which make it
1471 inappropriate to send to a publicly archived mailing list, then see
1472 "SECURITY VULNERABILITY CONTACT INFORMATION" in perlsec for details of
1473 how to report the issue.
1474
1476 The Changes file for an explanation of how to view exhaustive details
1477 on what changed.
1478 The INSTALL file for how to build Perl.
1480 The README file for general stuff.
1482 The Artistic and Copying files for copyright information.
1484perl v5.26.3 2018-03-23 PERL5240DELTA(1)