1PERL5140DELTA(1) Perl Programmers Reference Guide PERL5140DELTA(1)
2
6 perl5140delta - what is new for perl v5.14.0
7
9 This document describes differences between the 5.12.0 release and the
10 5.14.0 release.
11 If you are upgrading from an earlier release such as 5.10.0, first read
13 perl5120delta, which describes differences between 5.10.0 and 5.12.0.
14 Some of the bug fixes in this release have been backported to
16 subsequent releases of 5.12.x. Those are indicated with the 5.12.x
17 version in parentheses.
18
20 As described in perlpolicy, the release of Perl 5.14.0 marks the
21 official end of support for Perl 5.10. Users of Perl 5.10 or earlier
22 should consider upgrading to a more recent release of Perl.
23
25 Unicode
26 Unicode Version 6.0 is now supported (mostly)
27 Perl comes with the Unicode 6.0 data base updated with Corrigendum #8
29 <http://www.unicode.org/versions/corrigendum8.html>, with one exception
30 noted below. See <http://unicode.org/versions/Unicode6.0.0/> for
31 details on the new release. Perl does not support any Unicode
32 provisional properties, including the new ones for this release.
33 Unicode 6.0 has chosen to use the name "BELL" for the character at
35 U+1F514, which is a symbol that looks like a bell, and is used in
36 Japanese cell phones. This conflicts with the long-standing Perl usage
37 of having "BELL" mean the ASCII "BEL" character, U+0007. In Perl 5.14,
38 "\N{BELL}" continues to mean U+0007, but its use generates a
39 deprecation warning message unless such warnings are turned off. The
40 new name for U+0007 in Perl is "ALERT", which corresponds nicely with
41 the existing shorthand sequence for it, "\a". "\N{BEL}" means U+0007,
42 with no warning given. The character at U+1F514 has no name in 5.14,
43 but can be referred to by "\N{U+1F514}". In Perl 5.16, "\N{BELL}" will
44 refer to U+1F514; all code that uses "\N{BELL}" should be converted to
45 use "\N{ALERT}", "\N{BEL}", or "\a" before upgrading.
46 Full functionality for "use feature 'unicode_strings'"
48 This release provides full functionality for "use feature
50 'unicode_strings'". Under its scope, all string operations executed
51 and regular expressions compiled (even if executed outside its scope)
52 have Unicode semantics. See "the 'unicode_strings' feature" in
53 feature. However, see "Inverted bracketed character classes and multi-
54 character folds", below.
55 This feature avoids most forms of the "Unicode Bug" (see "The "Unicode
57 Bug"" in perlunicode for details). If there is any possibility that
58 your code will process Unicode strings, you are strongly encouraged to
59 use this subpragma to avoid nasty surprises.
60 "\N{NAME}" and "charnames" enhancements
62 · "\N{NAME}" and "charnames::vianame" now know about the abbreviated
64 character names listed by Unicode, such as NBSP, SHY, LRO, ZWJ,
65 etc.; all customary abbreviations for the C0 and C1 control
66 characters (such as ACK, BEL, CAN, etc.); and a few new variants of
67 some C1 full names that are in common usage.
68 · Unicode has several named character sequences, in which particular
70 sequences of code points are given names. "\N{NAME}" now
71 recognizes these.
72 · "\N{NAME}", "charnames::vianame", and "charnames::viacode" now know
74 about every character in Unicode. In earlier releases of Perl,
75 they didn't know about the Hangul syllables nor several CJK
76 (Chinese/Japanese/Korean) characters.
77 · It is now possible to override Perl's abbreviations with your own
79 custom aliases.
80 · You can now create a custom alias of the ordinal of a character,
82 known by "\N{NAME}", "charnames::vianame()", and
83 "charnames::viacode()". Previously, aliases had to be to official
84 Unicode character names. This made it impossible to create an
85 alias for unnamed code points, such as those reserved for private
86 use.
87 · The new function charnames::string_vianame() is a run-time version
89 of "\N{NAME}}", returning the string of characters whose Unicode
90 name is its parameter. It can handle Unicode named character
91 sequences, whereas the pre-existing charnames::vianame() cannot, as
92 the latter returns a single code point.
93 See charnames for details on all these changes.
95 New warnings categories for problematic (non-)Unicode code points.
97 Three new warnings subcategories of "utf8" have been added. These
99 allow you to turn off some "utf8" warnings, while allowing other
100 warnings to remain on. The three categories are: "surrogate" when
101 UTF-16 surrogates are encountered; "nonchar" when Unicode non-character
102 code points are encountered; and "non_unicode" when code points above
103 the legal Unicode maximum of 0x10FFFF are encountered.
104 Any unsigned value can be encoded as a character
106 With this release, Perl is adopting a model that any unsigned value can
108 be treated as a code point and encoded internally (as utf8) without
109 warnings, not just the code points that are legal in Unicode. However,
110 unless utf8 or the corresponding sub-category (see previous item) of
111 lexical warnings have been explicitly turned off, outputting or
112 executing a Unicode-defined operation such as upper-casing on such a
113 code point generates a warning. Attempting to input these using strict
114 rules (such as with the ":encoding(UTF-8)" layer) will continue to
115 fail. Prior to this release, handling was inconsistent and in places,
116 incorrect.
117 Unicode non-characters, some of which previously were erroneously
119 considered illegal in places by Perl, contrary to the Unicode Standard,
120 are now always legal internally. Inputting or outputting them works
121 the same as with the non-legal Unicode code points, because the Unicode
122 Standard says they are (only) illegal for "open interchange".
123 Unicode database files not installed
125 The Unicode database files are no longer installed with Perl. This
127 doesn't affect any functionality in Perl and saves significant disk
128 space. If you need these files, you can download them from
129 <http://www.unicode.org/Public/zipped/6.0.0/>.
130 Regular Expressions
132 "(?^...)" construct signifies default modifiers
133 An ASCII caret "^" immediately following a "(?" in a regular expression
135 now means that the subexpression does not inherit surrounding modifiers
136 such as "/i", but reverts to the Perl defaults. Any modifiers
137 following the caret override the defaults.
138 Stringification of regular expressions now uses this notation. For
140 example, "qr/hlagh/i" would previously be stringified as
141 "(?i-xsm:hlagh)", but now it's stringified as "(?^i:hlagh)".
142 The main purpose of this change is to allow tests that rely on the
144 stringification not to have to change whenever new modifiers are added.
145 See "Extended Patterns" in perlre.
146 This change is likely to break code that compares stringified regular
148 expressions with fixed strings containing "?-xism".
149 "/d", "/l", "/u", and "/a" modifiers
151 Four new regular expression modifiers have been added. These are
153 mutually exclusive: one only can be turned on at a time.
154 · The "/l" modifier says to compile the regular expression as if it
156 were in the scope of "use locale", even if it is not.
157 · The "/u" modifier says to compile the regular expression as if it
159 were in the scope of a "use feature 'unicode_strings'" pragma.
160 · The "/d" (default) modifier is used to override any "use locale"
162 and "use feature 'unicode_strings'" pragmas in effect at the time
163 of compiling the regular expression.
164 · The "/a" regular expression modifier restricts "\s", "\d" and "\w"
166 and the POSIX ("[[:posix:]]") character classes to the ASCII range.
167 Their complements and "\b" and "\B" are correspondingly affected.
168 Otherwise, "/a" behaves like the "/u" modifier, in that case-
169 insensitive matching uses Unicode semantics.
170 If the "/a" modifier is repeated, then additionally in case-
172 insensitive matching, no ASCII character can match a non-ASCII
173 character. For example,
174 "k" =~ /\N{KELVIN SIGN}/ai
176 "\xDF" =~ /ss/ai
177 match but
179 "k" =~ /\N{KELVIN SIGN}/aai
181 "\xDF" =~ /ss/aai
182 do not match.
184 See "Modifiers" in perlre for more detail.
186 Non-destructive substitution
188 The substitution ("s///") and transliteration ("y///") operators now
190 support an "/r" option that copies the input variable, carries out the
191 substitution on the copy, and returns the result. The original remains
192 unmodified.
193 my $old = "cat";
195 my $new = $old =~ s/cat/dog/r;
196 # $old is "cat" and $new is "dog"
197 This is particularly useful with "map". See perlop for more examples.
199 Re-entrant regular expression engine
201 It is now safe to use regular expressions within "(?{...})" and
203 "(??{...})" code blocks inside regular expressions.
204 These blocks are still experimental, however, and still have problems
206 with lexical ("my") variables and abnormal exiting.
207 "use re '/flags'"
209 The "re" pragma now has the ability to turn on regular expression flags
211 till the end of the lexical scope:
212 use re "/x";
214 "foo" =~ / (.+) /; # /x implied
215 See "'/flags' mode" in re for details.
217 \o{...} for octals
219 There is a new octal escape sequence, "\o", in doublequote-like
221 contexts. This construct allows large octal ordinals beyond the
222 current max of 0777 to be represented. It also allows you to specify a
223 character in octal which can safely be concatenated with other regex
224 snippets and which won't be confused with being a backreference to a
225 regex capture group. See "Capture groups" in perlre.
226 Add "\p{Titlecase}" as a synonym for "\p{Title}"
228 This synonym is added for symmetry with the Unicode property names
230 "\p{Uppercase}" and "\p{Lowercase}".
231 Regular expression debugging output improvement
233 Regular expression debugging output (turned on by "use re 'debug'") now
235 uses hexadecimal when escaping non-ASCII characters, instead of octal.
236 Return value of "delete $+{...}"
238 Custom regular expression engines can now determine the return value of
240 "delete" on an entry of "%+" or "%-".
241 Syntactical Enhancements
243 Array and hash container functions accept references
244 Warning: This feature is considered experimental, as the exact
246 behaviour may change in a future version of Perl.
247 All builtin functions that operate directly on array or hash containers
249 now also accept unblessed hard references to arrays or hashes:
250 |----------------------------+---------------------------|
252 | Traditional syntax | Terse syntax |
253 |----------------------------+---------------------------|
254 | push @$arrayref, @stuff | push $arrayref, @stuff |
255 | unshift @$arrayref, @stuff | unshift $arrayref, @stuff |
256 | pop @$arrayref | pop $arrayref |
257 | shift @$arrayref | shift $arrayref |
258 | splice @$arrayref, 0, 2 | splice $arrayref, 0, 2 |
259 | keys %$hashref | keys $hashref |
260 | keys @$arrayref | keys $arrayref |
261 | values %$hashref | values $hashref |
262 | values @$arrayref | values $arrayref |
263 | ($k,$v) = each %$hashref | ($k,$v) = each $hashref |
264 | ($k,$v) = each @$arrayref | ($k,$v) = each $arrayref |
265 |----------------------------+---------------------------|
266 This allows these builtin functions to act on long dereferencing chains
268 or on the return value of subroutines without needing to wrap them in
269 "@{}" or "%{}":
270 push @{$obj->tags}, $new_tag; # old way
272 push $obj->tags, $new_tag; # new way
273 for ( keys %{$hoh->{genres}{artists}} ) {...} # old way
275 for ( keys $hoh->{genres}{artists} ) {...} # new way
276 Single term prototype
278 The "+" prototype is a special alternative to "$" that acts like
280 "\[@%]" when given a literal array or hash variable, but will otherwise
281 force scalar context on the argument. See "Prototypes" in perlsub.
282 "package" block syntax
284 A package declaration can now contain a code block, in which case the
286 declaration is in scope inside that block only. So "package Foo { ...
287 }" is precisely equivalent to "{ package Foo; ... }". It also works
288 with a version number in the declaration, as in "package Foo 1.2 { ...
289 }", which is its most attractive feature. See perlfunc.
290 Statement labels can appear in more places
292 Statement labels can now occur before any type of statement or
294 declaration, such as "package".
295 Stacked labels
297 Multiple statement labels can now appear before a single statement.
299 Uppercase X/B allowed in hexadecimal/binary literals
301 Literals may now use either upper case "0X..." or "0B..." prefixes, in
303 addition to the already supported "0x..." and "0b..." syntax [perl
304 #76296].
305 C, Ruby, Python, and PHP already support this syntax, and it makes Perl
307 more internally consistent: a round-trip with "eval sprintf "%#X",
308 0x10" now returns 16, just like "eval sprintf "%#x", 0x10".
309 Overridable tie functions
311 "tie", "tied" and "untie" can now be overridden [perl #75902].
313 Exception Handling
315 To make them more reliable and consistent, several changes have been
316 made to how "die", "warn", and $@ behave.
317 · When an exception is thrown inside an "eval", the exception is no
319 longer at risk of being clobbered by destructor code running during
320 unwinding. Previously, the exception was written into $@ early in
321 the throwing process, and would be overwritten if "eval" was used
322 internally in the destructor for an object that had to be freed
323 while exiting from the outer "eval". Now the exception is written
324 into $@ last thing before exiting the outer "eval", so the code
325 running immediately thereafter can rely on the value in $@
326 correctly corresponding to that "eval". ($@ is still also set
327 before exiting the "eval", for the sake of destructors that rely on
328 this.)
329 Likewise, a "local $@" inside an "eval" no longer clobbers any
331 exception thrown in its scope. Previously, the restoration of $@
332 upon unwinding would overwrite any exception being thrown. Now the
333 exception gets to the "eval" anyway. So "local $@" is safe before
334 a "die".
335 Exceptions thrown from object destructors no longer modify the $@
337 of the surrounding context. (If the surrounding context was
338 exception unwinding, this used to be another way to clobber the
339 exception being thrown.) Previously such an exception was
340 sometimes emitted as a warning, and then either was string-appended
341 to the surrounding $@ or completely replaced the surrounding $@,
342 depending on whether that exception and the surrounding $@ were
343 strings or objects. Now, an exception in this situation is always
344 emitted as a warning, leaving the surrounding $@ untouched. In
345 addition to object destructors, this also affects any function call
346 run by XS code using the "G_KEEPERR" flag.
347 · Warnings for "warn" can now be objects in the same way as
349 exceptions for "die". If an object-based warning gets the default
350 handling of writing to standard error, it is stringified as before
351 with the filename and line number appended. But a $SIG{__WARN__}
352 handler now receives an object-based warning as an object, where
353 previously it was passed the result of stringifying the object.
354 Other Enhancements
356 Assignment to $0 sets the legacy process name with prctl() on Linux
357 On Linux the legacy process name is now set with prctl(2), in addition
359 to altering the POSIX name via "argv[0]", as Perl has done since
360 version 4.000. Now system utilities that read the legacy process name
361 such as ps, top, and killall recognize the name you set when assigning
362 to $0. The string you supply is truncated at 16 bytes; this limitation
363 is imposed by Linux.
364 srand() now returns the seed
366 This allows programs that need to have repeatable results not to have
368 to come up with their own seed-generating mechanism. Instead, they can
369 use srand() and stash the return value for future use. One example is
370 a test program with too many combinations to test comprehensively in
371 the time available for each run. It can test a random subset each time
372 and, should there be a failure, log the seed used for that run so this
373 can later be used to produce the same results.
374 printf-like functions understand post-1980 size modifiers
376 Perl's printf and sprintf operators, and Perl's internal printf
378 replacement function, now understand the C90 size modifiers "hh"
379 ("char"), "z" ("size_t"), and "t" ("ptrdiff_t"). Also, when compiled
380 with a C99 compiler, Perl now understands the size modifier "j"
381 ("intmax_t") (but this is not portable).
382 So, for example, on any modern machine, "sprintf("%hhd", 257)" returns
384 "1".
385 New global variable "${^GLOBAL_PHASE}"
387 A new global variable, "${^GLOBAL_PHASE}", has been added to allow
389 introspection of the current phase of the Perl interpreter. It's
390 explained in detail in "${^GLOBAL_PHASE}" in perlvar and in "BEGIN,
391 UNITCHECK, CHECK, INIT and END" in perlmod.
392 "-d:-foo" calls "Devel::foo::unimport"
394 The syntax -d:foo was extended in 5.6.1 to make -d:foo=bar equivalent
396 to -MDevel::foo=bar, which expands internally to "use Devel::foo
397 'bar'". Perl now allows prefixing the module name with -, with the
398 same semantics as -M; that is:
399 "-d:-foo"
401 Equivalent to -M-Devel::foo: expands to "no Devel::foo" and calls
402 "Devel::foo->unimport()" if that method exists.
403 "-d:-foo=bar"
405 Equivalent to -M-Devel::foo=bar: expands to "no Devel::foo 'bar'",
406 and calls "Devel::foo->unimport("bar")" if that method exists.
407 This is particularly useful for suppressing the default actions of a
409 "Devel::*" module's "import" method whilst still loading it for
410 debugging.
411 Filehandle method calls load IO::File on demand
413 When a method call on a filehandle would die because the method cannot
415 be resolved and IO::File has not been loaded, Perl now loads IO::File
416 via "require" and attempts method resolution again:
417 open my $fh, ">", $file;
419 $fh->binmode(":raw"); # loads IO::File and succeeds
420 This also works for globs like "STDOUT", "STDERR", and "STDIN":
422 STDOUT->autoflush(1);
424 Because this on-demand load happens only if method resolution fails,
426 the legacy approach of manually loading an IO::File parent class for
427 partial method support still works as expected:
428 use IO::Handle;
430 open my $fh, ">", $file;
431 $fh->autoflush(1); # IO::File not loaded
432 Improved IPv6 support
434 The "Socket" module provides new affordances for IPv6, including
436 implementations of the "Socket::getaddrinfo()" and
437 "Socket::getnameinfo()" functions, along with related constants and a
438 handful of new functions. See Socket.
439 DTrace probes now include package name
441 The "DTrace" probes now include an additional argument, "arg3", which
443 contains the package the subroutine being entered or left was compiled
444 in.
445 For example, using the following DTrace script:
447 perl$target:::sub-entry
449 {
450 printf("%s::%s\n", copyinstr(arg0), copyinstr(arg3));
451 }
452 and then running:
454 $ perl -e 'sub test { }; test'
456 "DTrace" will print:
458 main::test
460 New C APIs
462 See "Internal Changes".
463
465 User-defined regular expression properties
466 "User-Defined Character Properties" in perlunicode documented that you
467 can create custom properties by defining subroutines whose names begin
468 with "In" or "Is". However, Perl did not actually enforce that naming
469 restriction, so "\p{foo::bar}" could call foo::bar() if it existed.
470 The documented convention is now enforced.
471 Also, Perl no longer allows tainted regular expressions to invoke a
473 user-defined property. It simply dies instead [perl #82616].
474
476 Perl 5.14.0 is not binary-compatible with any previous stable release.
477 In addition to the sections that follow, see "C API Changes".
479 Regular Expressions and String Escapes
481 Inverted bracketed character classes and multi-character folds
482 Some characters match a sequence of two or three characters in "/i"
484 regular expression matching under Unicode rules. One example is "LATIN
485 SMALL LETTER SHARP S" which matches the sequence "ss".
486 'ss' =~ /\A[\N{LATIN SMALL LETTER SHARP S}]\z/i # Matches
488 This, however, can lead to very counter-intuitive results, especially
490 when inverted. Because of this, Perl 5.14 does not use multi-character
491 "/i" matching in inverted character classes.
492 'ss' =~ /\A[^\N{LATIN SMALL LETTER SHARP S}]+\z/i # ???
494 This should match any sequences of characters that aren't the "SHARP S"
496 nor what "SHARP S" matches under "/i". "s" isn't "SHARP S", but
497 Unicode says that "ss" is what "SHARP S" matches under "/i". So which
498 one "wins"? Do you fail the match because the string has "ss" or accept
499 it because it has an "s" followed by another "s"?
500 Earlier releases of Perl did allow this multi-character matching, but
502 due to bugs, it mostly did not work.
503 \400-\777
505 In certain circumstances, "\400"-"\777" in regexes have behaved
507 differently than they behave in all other doublequote-like contexts.
508 Since 5.10.1, Perl has issued a deprecation warning when this happens.
509 Now, these literals behave the same in all doublequote-like contexts,
510 namely to be equivalent to "\x{100}"-"\x{1FF}", with no deprecation
511 warning.
512 Use of "\400"-"\777" in the command-line option -0 retain their
514 conventional meaning. They slurp whole input files; previously, this
515 was documented only for -0777.
516 Because of various ambiguities, you should use the new "\o{...}"
518 construct to represent characters in octal instead.
519 Most "\p{}" properties are now immune to case-insensitive matching
521 For most Unicode properties, it doesn't make sense to have them match
523 differently under "/i" case-insensitive matching. Doing so can lead to
524 unexpected results and potential security holes. For example
525 m/\p{ASCII_Hex_Digit}+/i
527 could previously match non-ASCII characters because of the Unicode
529 matching rules (although there were several bugs with this). Now
530 matching under "/i" gives the same results as non-"/i" matching except
531 for those few properties where people have come to expect differences,
532 namely the ones where casing is an integral part of their meaning, such
533 as "m/\p{Uppercase}/i" and "m/\p{Lowercase}/i", both of which match the
534 same code points as matched by "m/\p{Cased}/i". Details are in
535 "Unicode Properties" in perlrecharclass.
536 User-defined property handlers that need to match differently under
538 "/i" must be changed to read the new boolean parameter passed to them,
539 which is non-zero if case-insensitive matching is in effect and 0
540 otherwise. See "User-Defined Character Properties" in perlunicode.
541 \p{} implies Unicode semantics
543 Specifying a Unicode property in the pattern indicates that the pattern
545 is meant for matching according to Unicode rules, the way "\N{NAME}"
546 does.
547 Regular expressions retain their localeness when interpolated
549 Regular expressions compiled under "use locale" now retain this when
551 interpolated into a new regular expression compiled outside a "use
552 locale", and vice-versa.
553 Previously, one regular expression interpolated into another inherited
555 the localeness of the surrounding regex, losing whatever state it
556 originally had. This is considered a bug fix, but may trip up code
557 that has come to rely on the incorrect behaviour.
558 Stringification of regexes has changed
560 Default regular expression modifiers are now notated using "(?^...)".
562 Code relying on the old stringification will fail. This is so that
563 when new modifiers are added, such code won't have to keep changing
564 each time this happens, because the stringification will automatically
565 incorporate the new modifiers.
566 Code that needs to work properly with both old- and new-style regexes
568 can avoid the whole issue by using (for perls since 5.9.5; see re):
569 use re qw(regexp_pattern);
571 my ($pat, $mods) = regexp_pattern($re_ref);
572 If the actual stringification is important or older Perls need to be
574 supported, you can use something like the following:
575 # Accept both old and new-style stringification
577 my $modifiers = (qr/foobar/ =~ /\Q(?^/) ? "^" : "-xism";
578 And then use $modifiers instead of "-xism".
580 Run-time code blocks in regular expressions inherit pragmata
582 Code blocks in regular expressions ("(?{...})" and "(??{...})")
584 previously did not inherit pragmata (strict, warnings, etc.) if the
585 regular expression was compiled at run time as happens in cases like
586 these two:
587 use re "eval";
589 $foo =~ $bar; # when $bar contains (?{...})
590 $foo =~ /$bar(?{ $finished = 1 })/;
591 This bug has now been fixed, but code that relied on the buggy
593 behaviour may need to be fixed to account for the correct behaviour.
594 Stashes and Package Variables
596 Localised tied hashes and arrays are no longed tied
597 In the following:
599 tie @a, ...;
601 {
602 local @a;
603 # here, @a is a now a new, untied array
604 }
605 # here, @a refers again to the old, tied array
606 Earlier versions of Perl incorrectly tied the new local array. This
608 has now been fixed. This fix could however potentially cause a change
609 in behaviour of some code.
610 Stashes are now always defined
612 "defined %Foo::" now always returns true, even when no symbols have yet
614 been defined in that package.
615 This is a side-effect of removing a special-case kludge in the
617 tokeniser, added for 5.10.0, to hide side-effects of changes to the
618 internal storage of hashes. The fix drastically reduces hashes' memory
619 overhead.
620 Calling defined on a stash has been deprecated since 5.6.0, warned on
622 lexicals since 5.6.0, and warned for stashes and other package
623 variables since 5.12.0. "defined %hash" has always exposed an
624 implementation detail: emptying a hash by deleting all entries from it
625 does not make "defined %hash" false. Hence "defined %hash" is not
626 valid code to determine whether an arbitrary hash is empty. Instead,
627 use the behaviour of an empty %hash always returning false in scalar
628 context.
629 Clearing stashes
631 Stash list assignment "%foo:: = ()" used to make the stash temporarily
633 anonymous while it was being emptied. Consequently, any of its
634 subroutines referenced elsewhere would become anonymous, showing up as
635 "(unknown)" in "caller". They now retain their package names such that
636 "caller" returns the original sub name if there is still a reference to
637 its typeglob and "foo::__ANON__" otherwise [perl #79208].
638 Dereferencing typeglobs
640 If you assign a typeglob to a scalar variable:
642 $glob = *foo;
644 the glob that is copied to $glob is marked with a special flag
646 indicating that the glob is just a copy. This allows subsequent
647 assignments to $glob to overwrite the glob. The original glob,
648 however, is immutable.
649 Some Perl operators did not distinguish between these two types of
651 globs. This would result in strange behaviour in edge cases: "untie
652 $scalar" would not untie the scalar if the last thing assigned to it
653 was a glob (because it treated it as "untie *$scalar", which unties a
654 handle). Assignment to a glob slot (such as "*$glob = \@some_array")
655 would simply assign "\@some_array" to $glob.
656 To fix this, the "*{}" operator (including its *foo and *$foo forms)
658 has been modified to make a new immutable glob if its operand is a glob
659 copy. This allows operators that make a distinction between globs and
660 scalars to be modified to treat only immutable globs as globs. ("tie",
661 "tied" and "untie" have been left as they are for compatibility's sake,
662 but will warn. See "Deprecations".)
663 This causes an incompatible change in code that assigns a glob to the
665 return value of "*{}" when that operator was passed a glob copy. Take
666 the following code, for instance:
667 $glob = *foo;
669 *$glob = *bar;
670 The *$glob on the second line returns a new immutable glob. That new
672 glob is made an alias to *bar. Then it is discarded. So the second
673 assignment has no effect.
674 See <http://rt.perl.org/rt3/Public/Bug/Display.html?id=77810> for more
676 detail.
677 Magic variables outside the main package
679 In previous versions of Perl, magic variables like $!, %SIG, etc. would
681 "leak" into other packages. So %foo::SIG could be used to access
682 signals, "${"foo::!"}" (with strict mode off) to access C's "errno",
683 etc.
684 This was a bug, or an "unintentional" feature, which caused various ill
686 effects, such as signal handlers being wiped when modules were loaded,
687 etc.
688 This has been fixed (or the feature has been removed, depending on how
690 you see it).
691 local($_) strips all magic from $_
693 local() on scalar variables gives them a new value but keeps all their
695 magic intact. This has proven problematic for the default scalar
696 variable $_, where perlsub recommends that any subroutine that assigns
697 to $_ should first localize it. This would throw an exception if $_ is
698 aliased to a read-only variable, and could in general have various
699 unintentional side-effects.
700 Therefore, as an exception to the general rule, local($_) will not only
702 assign a new value to $_, but also remove all existing magic from it as
703 well.
704 Parsing of package and variable names
706 Parsing the names of packages and package variables has changed:
708 multiple adjacent pairs of colons, as in "foo::::bar", are now all
709 treated as package separators.
710 Regardless of this change, the exact parsing of package separators has
712 never been guaranteed and is subject to change in future Perl versions.
713 Changes to Syntax or to Perl Operators
715 "given" return values
716 "given" blocks now return the last evaluated expression, or an empty
718 list if the block was exited by "break". Thus you can now write:
719 my $type = do {
721 given ($num) {
722 break when undef;
723 "integer" when /^[+-]?[0-9]+$/;
724 "float" when /^[+-]?[0-9]+(?:\.[0-9]+)?$/;
725 "unknown";
726 }
727 };
728 See "Return value" in perlsyn for details.
730 Change in parsing of certain prototypes
732 Functions declared with the following prototypes now behave correctly
734 as unary functions:
735 *
737 \$ \% \@ \* \&
738 \[...]
739 ;$ ;*
740 ;\$ ;\% etc.
741 ;\[...]
742 Due to this bug fix [perl #75904], functions using the "(*)", "(;$)"
744 and "(;*)" prototypes are parsed with higher precedence than before.
745 So in the following example:
746 sub foo(;$);
748 foo $a < $b;
749 the second line is now parsed correctly as "foo($a) < $b", rather than
751 "foo($a < $b)". This happens when one of these operators is used in an
752 unparenthesised argument:
753 < > <= >= lt gt le ge
755 == != <=> eq ne cmp ~~
756 &
757 | ^
758 &&
759 || //
760 .. ...
761 ?:
762 = += -= *= etc.
763 , =>
764 Smart-matching against array slices
766 Previously, the following code resulted in a successful match:
768 my @a = qw(a y0 z);
770 my @b = qw(a x0 z);
771 @a[0 .. $#b] ~~ @b;
772 This odd behaviour has now been fixed [perl #77468].
774 Negation treats strings differently from before
776 The unary negation operator, "-", now treats strings that look like
778 numbers as numbers [perl #57706].
779 Negative zero
781 Negative zero (-0.0), when converted to a string, now becomes "0" on
783 all platforms. It used to become "-0" on some, but "0" on others.
784 If you still need to determine whether a zero is negative, use
786 "sprintf("%g", $zero) =~ /^-/" or the Data::Float module on CPAN.
787 ":=" is now a syntax error
789 Previously "my $pi := 4" was exactly equivalent to "my $pi : = 4", with
791 the ":" being treated as the start of an attribute list, ending before
792 the "=". The use of ":=" to mean ": =" was deprecated in 5.12.0, and
793 is now a syntax error. This allows future use of ":=" as a new token.
794 Outside the core's tests for it, we find no Perl 5 code on CPAN using
796 this construction, so we believe that this change will have little
797 impact on real-world codebases.
798 If it is absolutely necessary to have empty attribute lists (for
800 example, because of a code generator), simply avoid the error by adding
801 a space before the "=".
802 Change in the parsing of identifiers
804 Characters outside the Unicode "XIDStart" set are no longer allowed at
806 the beginning of an identifier. This means that certain accents and
807 marks that normally follow an alphabetic character may no longer be the
808 first character of an identifier.
809 Threads and Processes
811 Directory handles not copied to threads
812 On systems other than Windows that do not have a "fchdir" function,
814 newly-created threads no longer inherit directory handles from their
815 parent threads. Such programs would usually have crashed anyway [perl
816 #75154].
817 "close" on shared pipes
819 To avoid deadlocks, the "close" function no longer waits for the child
821 process to exit if the underlying file descriptor is still in use by
822 another thread. It returns true in such cases.
823 fork() emulation will not wait for signalled children
825 On Windows parent processes would not terminate until all forked
827 children had terminated first. However, "kill("KILL", ...)" is
828 inherently unstable on pseudo-processes, and "kill("TERM", ...)" might
829 not get delivered if the child is blocked in a system call.
830 To avoid the deadlock and still provide a safe mechanism to terminate
832 the hosting process, Perl now no longer waits for children that have
833 been sent a SIGTERM signal. It is up to the parent process to
834 waitpid() for these children if child-cleanup processing must be
835 allowed to finish. However, it is also then the responsibility of the
836 parent to avoid the deadlock by making sure the child process can't be
837 blocked on I/O.
838 See perlfork for more information about the fork() emulation on
840 Windows.
841 Configuration
843 Naming fixes in Policy_sh.SH may invalidate Policy.sh
844 Several long-standing typos and naming confusions in Policy_sh.SH have
846 been fixed, standardizing on the variable names used in config.sh.
847 This will change the behaviour of Policy.sh if you happen to have been
849 accidentally relying on its incorrect behaviour.
850 Perl source code is read in text mode on Windows
852 Perl scripts used to be read in binary mode on Windows for the benefit
854 of the ByteLoader module (which is no longer part of core Perl). This
855 had the side-effect of breaking various operations on the "DATA"
856 filehandle, including seek()/tell(), and even simply reading from
857 "DATA" after filehandles have been flushed by a call to system(),
858 backticks, fork() etc.
859 The default build options for Windows have been changed to read Perl
861 source code on Windows in text mode now. ByteLoader will (hopefully)
862 be updated on CPAN to automatically handle this situation [perl
863 #28106].
864
866 See also "Deprecated C APIs".
867 Omitting a space between a regular expression and subsequent word
869 Omitting the space between a regular expression operator or its
870 modifiers and the following word is deprecated. For example,
871 "m/foo/sand $bar" is for now still parsed as "m/foo/s and $bar", but
872 will now issue a warning.
873 "\cX"
875 The backslash-c construct was designed as a way of specifying non-
876 printable characters, but there were no restrictions (on ASCII
877 platforms) on what the character following the "c" could be. Now, a
878 deprecation warning is raised if that character isn't an ASCII
879 character. Also, a deprecation warning is raised for "\c{" (which is
880 the same as simply saying ";").
881 "\b{" and "\B{"
883 In regular expressions, a literal "{" immediately following a "\b" (not
884 in a bracketed character class) or a "\B{" is now deprecated to allow
885 for its future use by Perl itself.
886 Perl 4-era .pl libraries
888 Perl bundles a handful of library files that predate Perl 5. This
889 bundling is now deprecated for most of these files, which are now
890 available from CPAN. The affected files now warn when run, if they
891 were installed as part of the core.
892 This is a mandatory warning, not obeying -X or lexical warning bits.
894 The warning is modelled on that supplied by deprecate.pm for
895 deprecated-in-core .pm libraries. It points to the specific CPAN
896 distribution that contains the .pl libraries. The CPAN versions, of
897 course, do not generate the warning.
898 List assignment to $[
900 Assignment to $[ was deprecated and started to give warnings in Perl
901 version 5.12.0. This version of Perl (5.14) now also emits a warning
902 when assigning to $[ in list context. This fixes an oversight in
903 5.12.0.
904 Use of qw(...) as parentheses
906 Historically the parser fooled itself into thinking that "qw(...)"
907 literals were always enclosed in parentheses, and as a result you could
908 sometimes omit parentheses around them:
909 for $x qw(a b c) { ... }
911 The parser no longer lies to itself in this way. Wrap the list literal
913 in parentheses like this:
914 for $x (qw(a b c)) { ... }
916 This is being deprecated because the parentheses in "for $i (1,2,3) {
918 ... }" are not part of expression syntax. They are part of the
919 statement syntax, with the "for" statement wanting literal parentheses.
920 The synthetic parentheses that a "qw" expression acquired were only
921 intended to be treated as part of expression syntax.
922 Note that this does not change the behaviour of cases like:
924 use POSIX qw(setlocale localeconv);
926 our @EXPORT = qw(foo bar baz);
927 where parentheses were never required around the expression.
929 "\N{BELL}"
931 This is because Unicode is using that name for a different character.
932 See "Unicode Version 6.0 is now supported (mostly)" for more
933 explanation.
934 "?PATTERN?"
936 "?PATTERN?" (without the initial "m") has been deprecated and now
937 produces a warning. This is to allow future use of "?" in new
938 operators. The match-once functionality is still available as
939 "m?PATTERN?".
940 Tie functions on scalars holding typeglobs
942 Calling a tie function ("tie", "tied", "untie") with a scalar argument
943 acts on a filehandle if the scalar happens to hold a typeglob.
944 This is a long-standing bug that will be removed in Perl 5.16, as there
946 is currently no way to tie the scalar itself when it holds a typeglob,
947 and no way to untie a scalar that has had a typeglob assigned to it.
948 Now there is a deprecation warning whenever a tie function is used on a
950 handle without an explicit "*".
951 User-defined case-mapping
953 This feature is being deprecated due to its many issues, as documented
954 in "User-Defined Case Mappings (for serious hackers only)" in
955 perlunicode. This feature will be removed in Perl 5.16. Instead use
956 the CPAN module Unicode::Casing, which provides improved functionality.
957 Deprecated modules
959 The following module will be removed from the core distribution in a
960 future release, and should be installed from CPAN instead.
961 Distributions on CPAN that require this should add it to their
962 prerequisites. The core version of these module now issues a
963 deprecation warning.
964 If you ship a packaged version of Perl, either alone or as part of a
966 larger system, then you should carefully consider the repercussions of
967 core module deprecations. You may want to consider shipping your
968 default build of Perl with a package for the deprecated module that
969 installs into "vendor" or "site" Perl library directories. This will
970 inhibit the deprecation warnings.
971 Alternatively, you may want to consider patching lib/deprecate.pm to
973 provide deprecation warnings specific to your packaging system or
974 distribution of Perl, consistent with how your packaging system or
975 distribution manages a staged transition from a release where the
976 installation of a single package provides the given functionality, to a
977 later release where the system administrator needs to know to install
978 multiple packages to get that same functionality.
979 You can silence these deprecation warnings by installing the module in
981 question from CPAN. To install the latest version of it by role rather
982 than by name, just install "Task::Deprecations::5_14".
983 Devel::DProf
985 We strongly recommend that you install and use Devel::NYTProf
986 instead of Devel::DProf, as Devel::NYTProf offers significantly
987 improved profiling and reporting.
988
990 "Safe signals" optimisation
991 Signal dispatch has been moved from the runloop into control ops. This
992 should give a few percent speed increase, and eliminates nearly all the
993 speed penalty caused by the introduction of "safe signals" in 5.8.0.
994 Signals should still be dispatched within the same statement as they
995 were previously. If this does not happen, or if you find it possible
996 to create uninterruptible loops, this is a bug, and reports are
997 encouraged of how to recreate such issues.
998 Optimisation of shift() and pop() calls without arguments
1000 Two fewer OPs are used for shift() and pop() calls with no argument
1001 (with implicit @_). This change makes shift() 5% faster than "shift
1002 @_" on non-threaded perls, and 25% faster on threaded ones.
1003 Optimisation of regexp engine string comparison work
1005 The "foldEQ_utf8" API function for case-insensitive comparison of
1006 strings (which is used heavily by the regexp engine) was substantially
1007 refactored and optimised -- and its documentation much improved as a
1008 free bonus.
1009 Regular expression compilation speed-up
1011 Compiling regular expressions has been made faster when upgrading the
1012 regex to utf8 is necessary but this isn't known when the compilation
1013 begins.
1014 String appending is 100 times faster
1016 When doing a lot of string appending, perls built to use the system's
1017 "malloc" could end up allocating a lot more memory than needed in a
1018 inefficient way.
1019 "sv_grow", the function used to allocate more memory if necessary when
1021 appending to a string, has been taught to round up the memory it
1022 requests to a certain geometric progression, making it much faster on
1023 certain platforms and configurations. On Win32, it's now about 100
1024 times faster.
1025 Eliminate "PL_*" accessor functions under ithreads
1027 When "MULTIPLICITY" was first developed, and interpreter state moved
1028 into an interpreter struct, thread- and interpreter-local "PL_*"
1029 variables were defined as macros that called accessor functions
1030 (returning the address of the value) outside the Perl core. The intent
1031 was to allow members within the interpreter struct to change size
1032 without breaking binary compatibility, so that bug fixes could be
1033 merged to a maintenance branch that necessitated such a size change.
1034 This mechanism was redundant and penalised well-behaved code. It has
1035 been removed.
1036 Freeing weak references
1038 When there are many weak references to an object, freeing that object
1039 can under some circumstances take O(N*N) time to free, where N is the
1040 number of references. The circumstances in which this can happen have
1041 been reduced [perl #75254]
1042 Lexical array and hash assignments
1044 An earlier optimisation to speed up "my @array = ..." and "my %hash =
1045 ..." assignments caused a bug and was disabled in Perl 5.12.0.
1046 Now we have found another way to speed up these assignments [perl
1048 #82110].
1049 @_ uses less memory
1051 Previously, @_ was allocated for every subroutine at compile time with
1052 enough space for four entries. Now this allocation is done on demand
1053 when the subroutine is called [perl #72416].
1054 Size optimisations to SV and HV structures
1056 "xhv_fill" has been eliminated from "struct xpvhv", saving 1 IV per
1057 hash and on some systems will cause "struct xpvhv" to become cache-
1058 aligned. To avoid this memory saving causing a slowdown elsewhere,
1059 boolean use of "HvFILL" now calls "HvTOTALKEYS" instead (which is
1060 equivalent), so while the fill data when actually required are now
1061 calculated on demand, cases when this needs to be done should be rare.
1062 The order of structure elements in SV bodies has changed. Effectively,
1064 the NV slot has swapped location with STASH and MAGIC. As all access
1065 to SV members is via macros, this should be completely transparent.
1066 This change allows the space saving for PVHVs documented above, and may
1067 reduce the memory allocation needed for PVIVs on some architectures.
1068 "XPV", "XPVIV", and "XPVNV" now allocate only the parts of the "SV"
1070 body they actually use, saving some space.
1071 Scalars containing regular expressions now allocate only the part of
1073 the "SV" body they actually use, saving some space.
1074 Memory consumption improvements to Exporter
1076 The @EXPORT_FAIL AV is no longer created unless needed, hence neither
1077 is the typeglob backing it. This saves about 200 bytes for every
1078 package that uses Exporter but doesn't use this functionality.
1079 Memory savings for weak references
1081 For weak references, the common case of just a single weak reference
1082 per referent has been optimised to reduce the storage required. In
1083 this case it saves the equivalent of one small Perl array per referent.
1084 "%+" and "%-" use less memory
1086 The bulk of the "Tie::Hash::NamedCapture" module used to be in the Perl
1087 core. It has now been moved to an XS module to reduce overhead for
1088 programs that do not use "%+" or "%-".
1089 Multiple small improvements to threads
1091 The internal structures of threading now make fewer API calls and fewer
1092 allocations, resulting in noticeably smaller object code.
1093 Additionally, many thread context checks have been deferred so they're
1094 done only as needed (although this is only possible for non-debugging
1095 builds).
1096 Adjacent pairs of nextstate opcodes are now optimized away
1098 Previously, in code such as
1099 use constant DEBUG => 0;
1101 sub GAK {
1103 warn if DEBUG;
1104 print "stuff\n";
1105 }
1106 the ops for "warn if DEBUG" would be folded to a "null" op
1108 ("ex-const"), but the "nextstate" op would remain, resulting in a
1109 runtime op dispatch of "nextstate", "nextstate", etc.
1110 The execution of a sequence of "nextstate" ops is indistinguishable
1112 from just the last "nextstate" op so the peephole optimizer now
1113 eliminates the first of a pair of "nextstate" ops except when the first
1114 carries a label, since labels must not be eliminated by the optimizer,
1115 and label usage isn't conclusively known at compile time.
1116
1118 New Modules and Pragmata
1119 · CPAN::Meta::YAML 0.003 has been added as a dual-life module. It
1120 supports a subset of YAML sufficient for reading and writing
1121 META.yml and MYMETA.yml files included with CPAN distributions or
1122 generated by the module installation toolchain. It should not be
1123 used for any other general YAML parsing or generation task.
1124 · CPAN::Meta version 2.110440 has been added as a dual-life module.
1126 It provides a standard library to read, interpret and write CPAN
1127 distribution metadata files (like META.json and META.yml) that
1128 describe a distribution, its contents, and the requirements for
1129 building it and installing it. The latest CPAN distribution
1130 metadata specification is included as CPAN::Meta::Spec and notes on
1131 changes in the specification over time are given in
1132 CPAN::Meta::History.
1133 · HTTP::Tiny 0.012 has been added as a dual-life module. It is a
1135 very small, simple HTTP/1.1 client designed for simple GET requests
1136 and file mirroring. It has been added so that CPAN.pm and CPANPLUS
1137 can "bootstrap" HTTP access to CPAN using pure Perl without relying
1138 on external binaries like curl(1) or wget(1).
1139 · JSON::PP 2.27105 has been added as a dual-life module to allow CPAN
1141 clients to read META.json files in CPAN distributions.
1142 · Module::Metadata 1.000004 has been added as a dual-life module. It
1144 gathers package and POD information from Perl module files. It is
1145 a standalone module based on Module::Build::ModuleInfo for use by
1146 other module installation toolchain components.
1147 Module::Build::ModuleInfo has been deprecated in favor of this
1148 module instead.
1149 · Perl::OSType 1.002 has been added as a dual-life module. It maps
1151 Perl operating system names (like "dragonfly" or "MSWin32") to more
1152 generic types with standardized names (like "Unix" or "Windows").
1153 It has been refactored out of Module::Build and ExtUtils::CBuilder
1154 and consolidates such mappings into a single location for easier
1155 maintenance.
1156 · The following modules were added by the Unicode::Collate upgrade.
1158 See below for details.
1159 Unicode::Collate::CJK::Big5
1161 Unicode::Collate::CJK::GB2312
1163 Unicode::Collate::CJK::JISX0208
1165 Unicode::Collate::CJK::Korean
1167 Unicode::Collate::CJK::Pinyin
1169 Unicode::Collate::CJK::Stroke
1171 · Version::Requirements version 0.101020 has been added as a dual-
1173 life module. It provides a standard library to model and
1174 manipulates module prerequisites and version constraints defined in
1175 CPAN::Meta::Spec.
1176 Updated Modules and Pragma
1178 · attributes has been upgraded from version 0.12 to 0.14.
1179 · Archive::Extract has been upgraded from version 0.38 to 0.48.
1181 Updates since 0.38 include: a safe print method that guards
1183 Archive::Extract from changes to "$\"; a fix to the tests when run
1184 in core Perl; support for TZ files; a modification for the lzma
1185 logic to favour IO::Uncompress::Unlzma; and a fix for an issue with
1186 NetBSD-current and its new unzip(1) executable.
1187 · Archive::Tar has been upgraded from version 1.54 to 1.76.
1189 Important changes since 1.54 include the following:
1191 · Compatibility with busybox implementations of tar(1).
1193 · A fix so that write() and create_archive() close only
1195 filehandles they themselves opened.
1196 · A bug was fixed regarding the exit code of extract_archive.
1198 · The ptar(1) utility has a new option to allow safe creation of
1200 tarballs without world-writable files on Windows, allowing
1201 those archives to be uploaded to CPAN.
1202 · A new ptargrep(1) utility for using regular expressions against
1204 the contents of files in a tar archive.
1205 · pax extended headers are now skipped.
1207 · Attribute::Handlers has been upgraded from version 0.87 to 0.89.
1209 · autodie has been upgraded from version 2.06_01 to 2.1001.
1211 · AutoLoader has been upgraded from version 5.70 to 5.71.
1213 · The B module has been upgraded from version 1.23 to 1.29.
1215 It no longer crashes when taking apart a "y///" containing
1217 characters outside the octet range or compiled in a "use utf8"
1218 scope.
1219 The size of the shared object has been reduced by about 40%, with
1221 no reduction in functionality.
1222 · B::Concise has been upgraded from version 0.78 to 0.83.
1224 B::Concise marks rv2sv(), rv2av(), and rv2hv() ops with the new
1226 "OPpDEREF" flag as "DREFed".
1227 It no longer produces mangled output with the -tree option [perl
1229 #80632].
1230 · B::Debug has been upgraded from version 1.12 to 1.16.
1232 · B::Deparse has been upgraded from version 0.96 to 1.03.
1234 The deparsing of a "nextstate" op has changed when it has both a
1236 change of package relative to the previous nextstate, or a change
1237 of "%^H" or other state and a label. The label was previously
1238 emitted first, but is now emitted last (5.12.1).
1239 The "no 5.13.2" or similar form is now correctly handled by
1241 B::Deparse (5.12.3).
1242 B::Deparse now properly handles the code that applies a conditional
1244 pattern match against implicit $_ as it was fixed in [perl #20444].
1245 Deparsing of "our" followed by a variable with funny characters (as
1247 permitted under the "use utf8" pragma) has also been fixed [perl
1248 #33752].
1249 · B::Lint has been upgraded from version 1.11_01 to 1.13.
1251 · base has been upgraded from version 2.15 to 2.16.
1253 · Benchmark has been upgraded from version 1.11 to 1.12.
1255 · bignum has been upgraded from version 0.23 to 0.27.
1257 · Carp has been upgraded from version 1.15 to 1.20.
1259 Carp now detects incomplete caller() overrides and avoids using
1261 bogus @DB::args. To provide backtraces, Carp relies on particular
1262 behaviour of the caller() builtin. Carp now detects if other code
1263 has overridden this with an incomplete implementation, and modifies
1264 its backtrace accordingly. Previously incomplete overrides would
1265 cause incorrect values in backtraces (best case), or obscure fatal
1266 errors (worst case).
1267 This fixes certain cases of "Bizarre copy of ARRAY" caused by
1269 modules overriding caller() incorrectly (5.12.2).
1270 It now also avoids using regular expressions that cause Perl to
1272 load its Unicode tables, so as to avoid the "BEGIN not safe after
1273 errors" error that ensue if there has been a syntax error [perl
1274 #82854].
1275 · CGI has been upgraded from version 3.48 to 3.52.
1277 This provides the following security fixes: the MIME boundary in
1279 multipart_init() is now random and the handling of newlines
1280 embedded in header values has been improved.
1281 · Compress::Raw::Bzip2 has been upgraded from version 2.024 to 2.033.
1283 It has been updated to use bzip2(1) 1.0.6.
1285 · Compress::Raw::Zlib has been upgraded from version 2.024 to 2.033.
1287 · constant has been upgraded from version 1.20 to 1.21.
1289 Unicode constants work once more. They have been broken since Perl
1291 5.10.0 [CPAN RT #67525].
1292 · CPAN has been upgraded from version 1.94_56 to 1.9600.
1294 Major highlights:
1296 · much less configuration dialog hassle
1298 · support for META/MYMETA.json
1300 · support for local::lib
1302 · support for HTTP::Tiny to reduce the dependency on FTP sites
1304 · automatic mirror selection
1306 · iron out all known bugs in configure_requires
1308 · support for distributions compressed with bzip2(1)
1310 · allow Foo/Bar.pm on the command line to mean "Foo::Bar"
1312 · CPANPLUS has been upgraded from version 0.90 to 0.9103.
1314 A change to cpanp-run-perl resolves RT #55964
1316 <http://rt.cpan.org/Public/Bug/Display.html?id=55964> and RT #57106
1317 <http://rt.cpan.org/Public/Bug/Display.html?id=57106>, both of
1318 which related to failures to install distributions that use
1319 "Module::Install::DSL" (5.12.2).
1320 A dependency on Config was not recognised as a core module
1322 dependency. This has been fixed.
1323 CPANPLUS now includes support for META.json and MYMETA.json.
1325 · CPANPLUS::Dist::Build has been upgraded from version 0.46 to 0.54.
1327 · Data::Dumper has been upgraded from version 2.125 to 2.130_02.
1329 The indentation used to be off when $Data::Dumper::Terse was set.
1331 This has been fixed [perl #73604].
1332 This upgrade also fixes a crash when using custom sort functions
1334 that might cause the stack to change [perl #74170].
1335 Dumpxs no longer crashes with globs returned by *$io_ref [perl
1337 #72332].
1338 · DB_File has been upgraded from version 1.820 to 1.821.
1340 · DBM_Filter has been upgraded from version 0.03 to 0.04.
1342 · Devel::DProf has been upgraded from version 20080331.00 to
1344 20110228.00.
1345 Merely loading Devel::DProf now no longer triggers profiling to
1347 start. Both "use Devel::DProf" and "perl -d:DProf ..." behave as
1348 before and start the profiler.
1349 NOTE: Devel::DProf is deprecated and will be removed from a future
1351 version of Perl. We strongly recommend that you install and use
1352 Devel::NYTProf instead, as it offers significantly improved
1353 profiling and reporting.
1354 · Devel::Peek has been upgraded from version 1.04 to 1.07.
1356 · Devel::SelfStubber has been upgraded from version 1.03 to 1.05.
1358 · diagnostics has been upgraded from version 1.19 to 1.22.
1360 It now renders pod links slightly better, and has been taught to
1362 find descriptions for messages that share their descriptions with
1363 other messages.
1364 · Digest::MD5 has been upgraded from version 2.39 to 2.51.
1366 It is now safe to use this module in combination with threads.
1368 · Digest::SHA has been upgraded from version 5.47 to 5.61.
1370 "shasum" now more closely mimics sha1sum(1)/md5sum(1).
1372 "addfile" accepts all POSIX filenames.
1374 New SHA-512/224 and SHA-512/256 transforms (ref. NIST Draft FIPS
1376 180-4 [February 2011])
1377 · DirHandle has been upgraded from version 1.03 to 1.04.
1379 · Dumpvalue has been upgraded from version 1.13 to 1.16.
1381 · DynaLoader has been upgraded from version 1.10 to 1.13.
1383 It fixes a buffer overflow when passed a very long file name.
1385 It no longer inherits from AutoLoader; hence it no longer produces
1387 weird error messages for unsuccessful method calls on classes that
1388 inherit from DynaLoader [perl #84358].
1389 · Encode has been upgraded from version 2.39 to 2.42.
1391 Now, all 66 Unicode non-characters are treated the same way U+FFFF
1393 has always been treated: in cases when it was disallowed, all 66
1394 are disallowed, and in cases where it warned, all 66 warn.
1395 · Env has been upgraded from version 1.01 to 1.02.
1397 · Errno has been upgraded from version 1.11 to 1.13.
1399 The implementation of Errno has been refactored to use about 55%
1401 less memory.
1402 On some platforms with unusual header files, like Win32 gcc(1)
1404 using "mingw64" headers, some constants that weren't actually error
1405 numbers have been exposed by Errno. This has been fixed [perl
1406 #77416].
1407 · Exporter has been upgraded from version 5.64_01 to 5.64_03.
1409 Exporter no longer overrides $SIG{__WARN__} [perl #74472]
1411 · ExtUtils::CBuilder has been upgraded from version 0.27 to 0.280203.
1413 · ExtUtils::Command has been upgraded from version 1.16 to 1.17.
1415 · ExtUtils::Constant has been upgraded from 0.22 to 0.23.
1417 The AUTOLOAD helper code generated by
1419 "ExtUtils::Constant::ProxySubs" can now croak() for missing
1420 constants, or generate a complete "AUTOLOAD" subroutine in XS,
1421 allowing simplification of many modules that use it (Fcntl,
1422 File::Glob, GDBM_File, I18N::Langinfo, POSIX, Socket).
1423 ExtUtils::Constant::ProxySubs can now optionally push the names of
1425 all constants onto the package's @EXPORT_OK.
1426 · ExtUtils::Install has been upgraded from version 1.55 to 1.56.
1428 · ExtUtils::MakeMaker has been upgraded from version 6.56 to 6.57_05.
1430 · ExtUtils::Manifest has been upgraded from version 1.57 to 1.58.
1432 · ExtUtils::ParseXS has been upgraded from version 2.21 to 2.2210.
1434 · Fcntl has been upgraded from version 1.06 to 1.11.
1436 · File::Basename has been upgraded from version 2.78 to 2.82.
1438 · File::CheckTree has been upgraded from version 4.4 to 4.41.
1440 · File::Copy has been upgraded from version 2.17 to 2.21.
1442 · File::DosGlob has been upgraded from version 1.01 to 1.04.
1444 It allows patterns containing literal parentheses: they no longer
1446 need to be escaped. On Windows, it no longer adds an extra ./ to
1447 file names returned when the pattern is a relative glob with a
1448 drive specification, like C:*.pl [perl #71712].
1449 · File::Fetch has been upgraded from version 0.24 to 0.32.
1451 HTTP::Lite is now supported for the "http" scheme.
1453 The fetch(1) utility is supported on FreeBSD, NetBSD, and Dragonfly
1455 BSD for the "http" and "ftp" schemes.
1456 · File::Find has been upgraded from version 1.15 to 1.19.
1458 It improves handling of backslashes on Windows, so that paths like
1460 C:\dir\/file are no longer generated [perl #71710].
1461 · File::Glob has been upgraded from version 1.07 to 1.12.
1463 · File::Spec has been upgraded from version 3.31 to 3.33.
1465 Several portability fixes were made in File::Spec::VMS: a colon is
1467 now recognized as a delimiter in native filespecs; caret-escaped
1468 delimiters are recognized for better handling of extended
1469 filespecs; catpath() returns an empty directory rather than the
1470 current directory if the input directory name is empty; and
1471 abs2rel() properly handles Unix-style input (5.12.2).
1472 · File::stat has been upgraded from 1.02 to 1.05.
1474 The "-x" and "-X" file test operators now work correctly when run
1476 by the superuser.
1477 · Filter::Simple has been upgraded from version 0.84 to 0.86.
1479 · GDBM_File has been upgraded from 1.10 to 1.14.
1481 This fixes a memory leak when DBM filters are used.
1483 · Hash::Util has been upgraded from 0.07 to 0.11.
1485 Hash::Util no longer emits spurious "uninitialized" warnings when
1487 recursively locking hashes that have undefined values [perl
1488 #74280].
1489 · Hash::Util::FieldHash has been upgraded from version 1.04 to 1.09.
1491 · I18N::Collate has been upgraded from version 1.01 to 1.02.
1493 · I18N::Langinfo has been upgraded from version 0.03 to 0.08.
1495 langinfo() now defaults to using $_ if there is no argument given,
1497 just as the documentation has always claimed.
1498 · I18N::LangTags has been upgraded from version 0.35 to 0.35_01.
1500 · if has been upgraded from version 0.05 to 0.0601.
1502 · IO has been upgraded from version 1.25_02 to 1.25_04.
1504 This version of IO includes a new IO::Select, which now allows
1506 IO::Handle objects (and objects in derived classes) to be removed
1507 from an IO::Select set even if the underlying file descriptor is
1508 closed or invalid.
1509 · IPC::Cmd has been upgraded from version 0.54 to 0.70.
1511 Resolves an issue with splitting Win32 command lines. An argument
1513 consisting of the single character "0" used to be omitted (CPAN RT
1514 #62961).
1515 · IPC::Open3 has been upgraded from 1.05 to 1.09.
1517 open3() now produces an error if the "exec" call fails, allowing
1519 this condition to be distinguished from a child process that exited
1520 with a non-zero status [perl #72016].
1521 The internal xclose() routine now knows how to handle file
1523 descriptors as documented, so duplicating "STDIN" in a child
1524 process using its file descriptor now works [perl #76474].
1525 · IPC::SysV has been upgraded from version 2.01 to 2.03.
1527 · lib has been upgraded from version 0.62 to 0.63.
1529 · Locale::Maketext has been upgraded from version 1.14 to 1.19.
1531 Locale::Maketext now supports external caches.
1533 This upgrade also fixes an infinite loop in
1535 "Locale::Maketext::Guts::_compile()" when working with tainted
1536 values (CPAN RT #40727).
1537 "->maketext" calls now back up and restore $@ so error messages are
1539 not suppressed (CPAN RT #34182).
1540 · Log::Message has been upgraded from version 0.02 to 0.04.
1542 · Log::Message::Simple has been upgraded from version 0.06 to 0.08.
1544 · Math::BigInt has been upgraded from version 1.89_01 to 1.994.
1546 This fixes, among other things, incorrect results when computing
1548 binomial coefficients [perl #77640].
1549 It also prevents "sqrt($int)" from crashing under "use bigrat".
1551 [perl #73534].
1552 · Math::BigInt::FastCalc has been upgraded from version 0.19 to 0.28.
1554 · Math::BigRat has been upgraded from version 0.24 to 0.26_02.
1556 · Memoize has been upgraded from version 1.01_03 to 1.02.
1558 · MIME::Base64 has been upgraded from 3.08 to 3.13.
1560 Includes new functions to calculate the length of encoded and
1562 decoded base64 strings.
1563 Now provides encode_base64url() and decode_base64url() functions to
1565 process the base64 scheme for "URL applications".
1566 · Module::Build has been upgraded from version 0.3603 to 0.3800.
1568 A notable change is the deprecation of several modules.
1570 Module::Build::Version has been deprecated and Module::Build now
1571 relies on the version pragma directly. Module::Build::ModuleInfo
1572 has been deprecated in favor of a standalone copy called
1573 Module::Metadata. Module::Build::YAML has been deprecated in favor
1574 of CPAN::Meta::YAML.
1575 Module::Build now also generates META.json and MYMETA.json files in
1577 accordance with version 2 of the CPAN distribution metadata
1578 specification, CPAN::Meta::Spec. The older format META.yml and
1579 MYMETA.yml files are still generated.
1580 · Module::CoreList has been upgraded from version 2.29 to 2.47.
1582 Besides listing the updated core modules of this release, it also
1584 stops listing the "Filespec" module. That module never existed in
1585 core. The scripts generating Module::CoreList confused it with
1586 VMS::Filespec, which actually is a core module as of Perl 5.8.7.
1587 · Module::Load has been upgraded from version 0.16 to 0.18.
1589 · Module::Load::Conditional has been upgraded from version 0.34 to
1591 0.44.
1592 · The mro pragma has been upgraded from version 1.02 to 1.07.
1594 · NDBM_File has been upgraded from version 1.08 to 1.12.
1596 This fixes a memory leak when DBM filters are used.
1598 · Net::Ping has been upgraded from version 2.36 to 2.38.
1600 · NEXT has been upgraded from version 0.64 to 0.65.
1602 · Object::Accessor has been upgraded from version 0.36 to 0.38.
1604 · ODBM_File has been upgraded from version 1.07 to 1.10.
1606 This fixes a memory leak when DBM filters are used.
1608 · Opcode has been upgraded from version 1.15 to 1.18.
1610 · The overload pragma has been upgraded from 1.10 to 1.13.
1612 "overload::Method" can now handle subroutines that are themselves
1614 blessed into overloaded classes [perl #71998].
1615 The documentation has greatly improved. See "Documentation" below.
1617 · Params::Check has been upgraded from version 0.26 to 0.28.
1619 · The parent pragma has been upgraded from version 0.223 to 0.225.
1621 · Parse::CPAN::Meta has been upgraded from version 1.40 to 1.4401.
1623 The latest Parse::CPAN::Meta can now read YAML and JSON files using
1625 CPAN::Meta::YAML and JSON::PP, which are now part of the Perl core.
1626 · PerlIO::encoding has been upgraded from version 0.12 to 0.14.
1628 · PerlIO::scalar has been upgraded from 0.07 to 0.11.
1630 A read() after a seek() beyond the end of the string no longer
1632 thinks it has data to read [perl #78716].
1633 · PerlIO::via has been upgraded from version 0.09 to 0.11.
1635 · Pod::Html has been upgraded from version 1.09 to 1.11.
1637 · Pod::LaTeX has been upgraded from version 0.58 to 0.59.
1639 · Pod::Perldoc has been upgraded from version 3.15_02 to 3.15_03.
1641 · Pod::Simple has been upgraded from version 3.13 to 3.16.
1643 · POSIX has been upgraded from 1.19 to 1.24.
1645 It now includes constants for POSIX signal constants.
1647 · The re pragma has been upgraded from version 0.11 to 0.18.
1649 The "use re '/flags'" subpragma is new.
1651 The regmust() function used to crash when called on a regular
1653 expression belonging to a pluggable engine. Now it croaks instead.
1654 regmust() no longer leaks memory.
1656 · Safe has been upgraded from version 2.25 to 2.29.
1658 Coderefs returned by reval() and rdo() are now wrapped via
1660 wrap_code_refs() (5.12.1).
1661 This fixes a possible infinite loop when looking for coderefs.
1663 It adds several "version::vxs::*" routines to the default share.
1665 · SDBM_File has been upgraded from version 1.06 to 1.09.
1667 · SelfLoader has been upgraded from 1.17 to 1.18.
1669 It now works in taint mode [perl #72062].
1671 · The sigtrap pragma has been upgraded from version 1.04 to 1.05.
1673 It no longer tries to modify read-only arguments when generating a
1675 backtrace [perl #72340].
1676 · Socket has been upgraded from version 1.87 to 1.94.
1678 See "Improved IPv6 support" above.
1680 · Storable has been upgraded from version 2.22 to 2.27.
1682 Includes performance improvement for overloaded classes.
1684 This adds support for serialising code references that contain
1686 UTF-8 strings correctly. The Storable minor version number changed
1687 as a result, meaning that Storable users who set
1688 $Storable::accept_future_minor to a "FALSE" value will see errors
1689 (see "FORWARD COMPATIBILITY" in Storable for more details).
1690 Freezing no longer gets confused if the Perl stack gets reallocated
1692 during freezing [perl #80074].
1693 · Sys::Hostname has been upgraded from version 1.11 to 1.16.
1695 · Term::ANSIColor has been upgraded from version 2.02 to 3.00.
1697 · Term::UI has been upgraded from version 0.20 to 0.26.
1699 · Test::Harness has been upgraded from version 3.17 to 3.23.
1701 · Test::Simple has been upgraded from version 0.94 to 0.98.
1703 Among many other things, subtests without a "plan" or "no_plan" now
1705 have an implicit done_testing() added to them.
1706 · Thread::Semaphore has been upgraded from version 2.09 to 2.12.
1708 It provides two new methods that give more control over the
1710 decrementing of semaphores: "down_nb" and "down_force".
1711 · Thread::Queue has been upgraded from version 2.11 to 2.12.
1713 · The threads pragma has been upgraded from version 1.75 to 1.83.
1715 · The threads::shared pragma has been upgraded from version 1.32 to
1717 1.37.
1718 · Tie::Hash has been upgraded from version 1.03 to 1.04.
1720 Calling "Tie::Hash->TIEHASH()" used to loop forever. Now it
1722 "croak"s.
1723 · Tie::Hash::NamedCapture has been upgraded from version 0.06 to
1725 0.08.
1726 · Tie::RefHash has been upgraded from version 1.38 to 1.39.
1728 · Time::HiRes has been upgraded from version 1.9719 to 1.9721_01.
1730 · Time::Local has been upgraded from version 1.1901_01 to 1.2000.
1732 · Time::Piece has been upgraded from version 1.15_01 to 1.20_01.
1734 · Unicode::Collate has been upgraded from version 0.52_01 to 0.73.
1736 Unicode::Collate has been updated to use Unicode 6.0.0.
1738 Unicode::Collate::Locale now supports a plethora of new locales:
1740 ar, be, bg, de__phonebook, hu, hy, kk, mk, nso, om, tn, vi, hr, ig,
1741 ja, ko, ru, sq, se, sr, to, uk, zh, zh__big5han, zh__gb2312han,
1742 zh__pinyin, and zh__stroke.
1743 The following modules have been added:
1745 Unicode::Collate::CJK::Big5 for "zh__big5han" which makes tailoring
1747 of CJK Unified Ideographs in the order of CLDR's big5han ordering.
1748 Unicode::Collate::CJK::GB2312 for "zh__gb2312han" which makes
1750 tailoring of CJK Unified Ideographs in the order of CLDR's
1751 gb2312han ordering.
1752 Unicode::Collate::CJK::JISX0208 which makes tailoring of 6355 kanji
1754 (CJK Unified Ideographs) in the JIS X 0208 order.
1755 Unicode::Collate::CJK::Korean which makes tailoring of CJK Unified
1757 Ideographs in the order of CLDR's Korean ordering.
1758 Unicode::Collate::CJK::Pinyin for "zh__pinyin" which makes
1760 tailoring of CJK Unified Ideographs in the order of CLDR's pinyin
1761 ordering.
1762 Unicode::Collate::CJK::Stroke for "zh__stroke" which makes
1764 tailoring of CJK Unified Ideographs in the order of CLDR's stroke
1765 ordering.
1766 This also sees the switch from using the pure-Perl version of this
1768 module to the XS version.
1769 · Unicode::Normalize has been upgraded from version 1.03 to 1.10.
1771 · Unicode::UCD has been upgraded from version 0.27 to 0.32.
1773 A new function, Unicode::UCD::num(), has been added. This function
1775 returns the numeric value of the string passed it or "undef" if the
1776 string in its entirety has no "safe" numeric value. (For more
1777 detail, and for the definition of "safe", see "num()" in
1778 Unicode::UCD.)
1779 This upgrade also includes several bug fixes:
1781 charinfo()
1783 · It is now updated to Unicode Version 6.0.0 with Corrigendum
1784 #8, excepting that, just as with Perl 5.14, the code point
1785 at U+1F514 has no name.
1786 · Hangul syllable code points have the correct names, and
1788 their decompositions are always output without requiring
1789 Lingua::KO::Hangul::Util to be installed.
1790 · CJK (Chinese-Japanese-Korean) code points U+2A700 to
1792 U+2B734 and U+2B740 to U+2B81D are now properly handled.
1793 · Numeric values are now output for those CJK code points
1795 that have them.
1796 · Names output for code points with multiple aliases are now
1798 the corrected ones.
1799 charscript()
1801 This now correctly returns "Unknown" instead of "undef" for the
1802 script of a code point that hasn't been assigned another one.
1803 charblock()
1805 This now correctly returns "No_Block" instead of "undef" for
1806 the block of a code point that hasn't been assigned to another
1807 one.
1808 · The version pragma has been upgraded from 0.82 to 0.88.
1810 Because of a bug, now fixed, the is_strict() and is_lax() functions
1812 did not work when exported (5.12.1).
1813 · The warnings pragma has been upgraded from version 1.09 to 1.12.
1815 Calling "use warnings" without arguments is now significantly more
1817 efficient.
1818 · The warnings::register pragma has been upgraded from version 1.01
1820 to 1.02.
1821 It is now possible to register warning categories other than the
1823 names of packages using warnings::register. See perllexwarn(1) for
1824 more information.
1825 · XSLoader has been upgraded from version 0.10 to 0.13.
1827 · VMS::DCLsym has been upgraded from version 1.03 to 1.05.
1829 Two bugs have been fixed [perl #84086]:
1831 The symbol table name was lost when tying a hash, due to a thinko
1833 in "TIEHASH". The result was that all tied hashes interacted with
1834 the local symbol table.
1835 Unless a symbol table name had been explicitly specified in the
1837 call to the constructor, querying the special key ":LOCAL" failed
1838 to identify objects connected to the local symbol table.
1839 · The Win32 module has been upgraded from version 0.39 to 0.44.
1841 This release has several new functions: Win32::GetSystemMetrics(),
1843 Win32::GetProductInfo(), Win32::GetOSDisplayName().
1844 The names returned by Win32::GetOSName() and
1846 Win32::GetOSDisplayName() have been corrected.
1847 · XS::Typemap has been upgraded from version 0.03 to 0.05.
1849 Removed Modules and Pragmata
1851 As promised in Perl 5.12.0's release notes, the following modules have
1852 been removed from the core distribution, and if needed should be
1853 installed from CPAN instead.
1854 · Class::ISA has been removed from the Perl core. Prior version was
1856 0.36.
1857 · Pod::Plainer has been removed from the Perl core. Prior version
1859 was 1.02.
1860 · Switch has been removed from the Perl core. Prior version was
1862 2.16.
1863 The removal of Shell has been deferred until after 5.14, as the
1865 implementation of Shell shipped with 5.12.0 did not correctly issue the
1866 warning that it was to be removed from core.
1867
1869 New Documentation
1870 perlgpl
1871 perlgpl has been updated to contain GPL version 1, as is included in
1873 the README distributed with Perl (5.12.1).
1874 Perl 5.12.x delta files
1876 The perldelta files for Perl 5.12.1 to 5.12.3 have been added from the
1878 maintenance branch: perl5121delta, perl5122delta, perl5123delta.
1879 perlpodstyle
1881 New style guide for POD documentation, split mostly from the NOTES
1883 section of the pod2man(1) manpage.
1884 perlsource, perlinterp, perlhacktut, and perlhacktips
1886 See "perlhack and perlrepository revamp", below.
1888 Changes to Existing Documentation
1890 perlmodlib is now complete
1891 The perlmodlib manpage that came with Perl 5.12.0 was missing several
1893 modules due to a bug in the script that generates the list. This has
1894 been fixed [perl #74332] (5.12.1).
1895 Replace incorrect tr/// table in perlebcdic
1897 perlebcdic contains a helpful table to use in "tr///" to convert
1899 between EBCDIC and Latin1/ASCII. The table was the inverse of the one
1900 it describes, though the code that used the table worked correctly for
1901 the specific example given.
1902 The table has been corrected and the sample code changed to correspond.
1904 The table has also been changed to hex from octal, and the recipes in
1906 the pod have been altered to print out leading zeros to make all values
1907 the same length.
1908 Tricks for user-defined casing
1910 perlunicode now contains an explanation of how to override, mangle and
1912 otherwise tweak the way Perl handles upper-, lower- and other-case
1913 conversions on Unicode data, and how to provide scoped changes to alter
1914 one's own code's behaviour without stomping on anybody else's.
1915 INSTALL explicitly states that Perl requires a C89 compiler
1917 This was already true, but it's now Officially Stated For The Record
1919 (5.12.2).
1920 Explanation of "\xHH" and "\oOOO" escapes
1922 perlop has been updated with more detailed explanation of these two
1924 character escapes.
1925 -0NNN switch
1927 In perlrun, the behaviour of the -0NNN switch for -0400 or higher has
1929 been clarified (5.12.2).
1930 Maintenance policy
1932 perlpolicy now contains the policy on what patches are acceptable for
1934 maintenance branches (5.12.1).
1935 Deprecation policy
1937 perlpolicy now contains the policy on compatibility and deprecation
1939 along with definitions of terms like "deprecation" (5.12.2).
1940 New descriptions in perldiag
1942 The following existing diagnostics are now documented:
1944 · Ambiguous use of %c resolved as operator %c
1946 · Ambiguous use of %c{%s} resolved to %c%s
1948 · Ambiguous use of %c{%s[...]} resolved to %c%s[...]
1950 · Ambiguous use of %c{%s{...}} resolved to %c%s{...}
1952 · Ambiguous use of -%s resolved as -&%s()
1954 · Invalid strict version format (%s)
1956 · Invalid version format (%s)
1958 · Invalid version object
1960 perlbook
1962 perlbook has been expanded to cover many more popular books.
1964 "SvTRUE" macro
1966 The documentation for the "SvTRUE" macro in perlapi was simply wrong in
1968 stating that get-magic is not processed. It has been corrected.
1969 op manipulation functions
1971 Several API functions that process optrees have been newly documented.
1973 perlvar revamp
1975 perlvar reorders the variables and groups them by topic. Each variable
1977 introduced after Perl 5.000 notes the first version in which it is
1978 available. perlvar also has a new section for deprecated variables to
1979 note when they were removed.
1980 Array and hash slices in scalar context
1982 These are now documented in perldata.
1984 "use locale" and formats
1986 perlform and perllocale have been corrected to state that "use locale"
1988 affects formats.
1989 overload
1991 overload's documentation has practically undergone a rewrite. It is
1993 now much more straightforward and clear.
1994 perlhack and perlrepository revamp
1996 The perlhack document is now much shorter, and focuses on the Perl 5
1998 development process and submitting patches to Perl. The technical
1999 content has been moved to several new documents, perlsource,
2000 perlinterp, perlhacktut, and perlhacktips. This technical content has
2001 been only lightly edited.
2002 The perlrepository document has been renamed to perlgit. This new
2004 document is just a how-to on using git with the Perl source code. Any
2005 other content that used to be in perlrepository has been moved to
2006 perlhack.
2007 Time::Piece examples
2009 Examples in perlfaq4 have been updated to show the use of Time::Piece.
2011
2013 The following additions or changes have been made to diagnostic output,
2014 including warnings and fatal error messages. For the complete list of
2015 diagnostic messages, see perldiag.
2016 New Diagnostics
2018 New Errors
2019 Closure prototype called
2021 This error occurs when a subroutine reference passed to an
2022 attribute handler is called, if the subroutine is a closure [perl
2023 #68560].
2024 Insecure user-defined property %s
2026 Perl detected tainted data when trying to compile a regular
2027 expression that contains a call to a user-defined character
2028 property function, meaning "\p{IsFoo}" or "\p{InFoo}". See "User-
2029 Defined Character Properties" in perlunicode and perlsec.
2030 panic: gp_free failed to free glob pointer - something is repeatedly
2032 re-creating entries
2033 This new error is triggered if a destructor called on an object in
2034 a typeglob that is being freed creates a new typeglob entry
2035 containing an object with a destructor that creates a new entry
2036 containing an object etc.
2037 Parsing code internal error (%s)
2039 This new fatal error is produced when parsing code supplied by an
2040 extension violates the parser's API in a detectable way.
2041 refcnt: fd %d%s
2043 This new error only occurs if a internal consistency check fails
2044 when a pipe is about to be closed.
2045 Regexp modifier "/%c" may not appear twice
2047 The regular expression pattern has one of the mutually exclusive
2048 modifiers repeated.
2049 Regexp modifiers "/%c" and "/%c" are mutually exclusive
2051 The regular expression pattern has more than one of the mutually
2052 exclusive modifiers.
2053 Using !~ with %s doesn't make sense
2055 This error occurs when "!~" is used with "s///r" or "y///r".
2056 New Warnings
2058 "\b{" is deprecated; use "\b\{" instead
2060 "\B{" is deprecated; use "\B\{" instead
2061 Use of an unescaped "{" immediately following a "\b" or "\B" is now
2062 deprecated in order to reserve its use for Perl itself in a future
2063 release.
2064 Operation "%s" returns its argument for ...
2066 Performing an operation requiring Unicode semantics (such as case-
2067 folding) on a Unicode surrogate or a non-Unicode character now
2068 triggers this warning.
2069 Use of qw(...) as parentheses is deprecated
2071 See "Use of qw(...) as parentheses", above, for details.
2072 Changes to Existing Diagnostics
2074 · The "Variable $foo is not imported" warning that precedes a "strict
2075 'vars'" error has now been assigned the "misc" category, so that
2076 "no warnings" will suppress it [perl #73712].
2077 · warn() and die() now produce "Wide character" warnings when fed a
2079 character outside the byte range if "STDERR" is a byte-sized
2080 handle.
2081 · The "Layer does not match this perl" error message has been
2083 replaced with these more helpful messages [perl #73754]:
2084 · PerlIO layer function table size (%d) does not match size
2086 expected by this perl (%d)
2087 · PerlIO layer instance size (%d) does not match size expected by
2089 this perl (%d)
2090 · The "Found = in conditional" warning that is emitted when a
2092 constant is assigned to a variable in a condition is now withheld
2093 if the constant is actually a subroutine or one generated by "use
2094 constant", since the value of the constant may not be known at the
2095 time the program is written [perl #77762].
2096 · Previously, if none of the gethostbyaddr(), gethostbyname() and
2098 gethostent() functions were implemented on a given platform, they
2099 would all die with the message "Unsupported socket function
2100 'gethostent' called", with analogous messages for getnet*() and
2101 getserv*(). This has been corrected.
2102 · The warning message about unrecognized regular expression escapes
2104 passed through has been changed to include any literal "{"
2105 following the two-character escape. For example, "\q{" is now
2106 emitted instead of "\q".
2107
2109 perlbug(1)
2110 · perlbug now looks in the EMAIL environment variable for a return
2112 address if the REPLY-TO and REPLYTO variables are empty.
2113 · perlbug did not previously generate a "From:" header, potentially
2115 resulting in dropped mail; it now includes that header.
2116 · The user's address is now used as the Return-Path.
2118 Many systems these days don't have a valid Internet domain name,
2120 and perlbug@perl.org does not accept email with a return-path that
2121 does not resolve. So the user's address is now passed to sendmail
2122 so it's less likely to get stuck in a mail queue somewhere [perl
2123 #82996].
2124 · perlbug now always gives the reporter a chance to change the email
2126 address it guesses for them (5.12.2).
2127 · perlbug should no longer warn about uninitialized values when using
2129 the -d and -v options (5.12.2).
2130 perl5db.pl
2132 · The remote terminal works after forking and spawns new sessions,
2134 one per forked process.
2135 ptargrep
2137 · ptargrep is a new utility to apply pattern matching to the contents
2139 of files in a tar archive. It comes with "Archive::Tar".
2140
2142 See also "Naming fixes in Policy_sh.SH may invalidate Policy.sh",
2143 above.
2144 · CCINCDIR and CCLIBDIR for the mingw64 cross-compiler are now
2146 correctly under $(CCHOME)\mingw\include and \lib rather than
2147 immediately below $(CCHOME).
2148 This means the "incpath", "libpth", "ldflags", "lddlflags" and
2150 "ldflags_nolargefiles" values in Config.pm and Config_heavy.pl are
2151 now set correctly.
2152 · "make test.valgrind" has been adjusted to account for cpan/dist/ext
2154 separation.
2155 · On compilers that support it, -Wwrite-strings is now added to
2157 cflags by default.
2158 · The Encode module can now (once again) be included in a static Perl
2160 build. The special-case handling for this situation got broken in
2161 Perl 5.11.0, and has now been repaired.
2162 · The previous default size of a PerlIO buffer (4096 bytes) has been
2164 increased to the larger of 8192 bytes and your local BUFSIZ.
2165 Benchmarks show that doubling this decade-old default increases
2166 read and write performance by around 25% to 50% when using the
2167 default layers of perlio on top of unix. To choose a non-default
2168 size, such as to get back the old value or to obtain an even larger
2169 value, configure with:
2170 ./Configure -Accflags=-DPERLIOBUF_DEFAULT_BUFSIZ=N
2172 where N is the desired size in bytes; it should probably be a
2174 multiple of your page size.
2175 · An "incompatible operand types" error in ternary expressions when
2177 building with "clang" has been fixed (5.12.2).
2178 · Perl now skips setuid File::Copy tests on partitions it detects
2180 mounted as "nosuid" (5.12.2).
2181
2183 New Platforms
2184 AIX Perl now builds on AIX 4.2 (5.12.1).
2185 Discontinued Platforms
2187 Apollo DomainOS
2188 The last vestiges of support for this platform have been excised
2189 from the Perl distribution. It was officially discontinued in
2190 version 5.12.0. It had not worked for years before that.
2191 MacOS Classic
2193 The last vestiges of support for this platform have been excised
2194 from the Perl distribution. It was officially discontinued in an
2195 earlier version.
2196 Platform-Specific Notes
2198 AIX
2199 · README.aix has been updated with information about the XL C/C++ V11
2201 compiler suite (5.12.2).
2202 ARM
2204 · The "d_u32align" configuration probe on ARM has been fixed
2206 (5.12.2).
2207 Cygwin
2209 · MakeMaker has been updated to build manpages on cygwin.
2211 · Improved rebase behaviour
2213 If a DLL is updated on cygwin the old imagebase address is reused.
2215 This solves most rebase errors, especially when updating on core
2216 DLL's. See
2217 http://www.tishler.net/jason/software/rebase/rebase-2.4.2.README
2218 <http://www.tishler.net/jason/software/rebase/rebase-2.4.2.README>
2219 for more information.
2220 · Support for the standard cygwin dll prefix (needed for FFIs)
2222 · Updated build hints file
2224 FreeBSD 7
2226 · FreeBSD 7 no longer contains /usr/bin/objformat. At build time,
2228 Perl now skips the objformat check for versions 7 and higher and
2229 assumes ELF (5.12.1).
2230 HP-UX
2232 · Perl now allows -Duse64bitint without promoting to "use64bitall" on
2234 HP-UX (5.12.1).
2235 IRIX
2237 · Conversion of strings to floating-point numbers is now more
2239 accurate on IRIX systems [perl #32380].
2240 Mac OS X
2242 · Early versions of Mac OS X (Darwin) had buggy implementations of
2244 the setregid(), setreuid(), setrgid(,) and setruid() functions, so
2245 Perl would pretend they did not exist.
2246 These functions are now recognised on Mac OS 10.5 (Leopard; Darwin
2248 9) and higher, as they have been fixed [perl #72990].
2249 MirBSD
2251 · Previously if you built Perl with a shared libperl.so on MirBSD
2253 (the default config), it would work up to the installation;
2254 however, once installed, it would be unable to find libperl. Path
2255 handling is now treated as in the other BSD dialects.
2256 NetBSD
2258 · The NetBSD hints file has been changed to make the system malloc
2260 the default.
2261 OpenBSD
2263 · OpenBSD > 3.7 has a new malloc implementation which is mmap-based,
2265 and as such can release memory back to the OS; however, Perl's use
2266 of this malloc causes a substantial slowdown, so we now default to
2267 using Perl's malloc instead [perl #75742].
2268 OpenVOS
2270 · Perl now builds again with OpenVOS (formerly known as Stratus VOS)
2272 [perl #78132] (5.12.3).
2273 Solaris
2275 · DTrace is now supported on Solaris. There used to be build
2277 failures, but these have been fixed [perl #73630] (5.12.3).
2278 VMS
2280 · Extension building on older (pre 7.3-2) VMS systems was broken
2282 because configure.com hit the DCL symbol length limit of 1K. We
2283 now work within this limit when assembling the list of extensions
2284 in the core build (5.12.1).
2285 · We fixed configuring and building Perl with -Uuseperlio (5.12.1).
2287 · "PerlIOUnix_open" now honours the default permissions on VMS.
2289 When "perlio" became the default and "unix" became the default
2291 bottom layer, the most common path for creating files from Perl
2292 became "PerlIOUnix_open", which has always explicitly used 0666 as
2293 the permission mask. This prevents inheriting permissions from RMS
2294 defaults and ACLs, so to avoid that problem, we now pass 0777 to
2295 open(). In the VMS CRTL, 0777 has a special meaning over and above
2296 intersecting with the current umask; specifically, it allows Unix
2297 syscalls to preserve native default permissions (5.12.3).
2298 · The shortening of symbols longer than 31 characters in the core C
2300 sources and in extensions is now by default done by the C compiler
2301 rather than by xsubpp (which could only do so for generated symbols
2302 in XS code). You can reenable xsubpp's symbol shortening by
2303 configuring with -Uuseshortenedsymbols, but you'll have some work
2304 to do to get the core sources to compile.
2305 · Record-oriented files (record format variable or variable with
2307 fixed control) opened for write by the "perlio" layer will now be
2308 line-buffered to prevent the introduction of spurious line breaks
2309 whenever the perlio buffer fills up.
2310 · git_version.h is now installed on VMS. This was an oversight in
2312 v5.12.0 which caused some extensions to fail to build (5.12.2).
2313 · Several memory leaks in stat() have been fixed (5.12.2).
2315 · A memory leak in Perl_rename() due to a double allocation has been
2317 fixed (5.12.2).
2318 · A memory leak in vms_fid_to_name() (used by realpath() and
2320 realname()> has been fixed (5.12.2).
2321 Windows
2323 See also "fork() emulation will not wait for signalled children" and
2325 "Perl source code is read in text mode on Windows", above.
2326 · Fixed build process for SDK2003SP1 compilers.
2328 · Compilation with Visual Studio 2010 is now supported.
2330 · When using old 32-bit compilers, the define "_USE_32BIT_TIME_T" is
2332 now set in $Config{ccflags}. This improves portability when
2333 compiling XS extensions using new compilers, but for a Perl
2334 compiled with old 32-bit compilers.
2335 · $Config{gccversion} is now set correctly when Perl is built using
2337 the mingw64 compiler from <http://mingw64.org> [perl #73754].
2338 · When building Perl with the mingw64 x64 cross-compiler "incpath",
2340 "libpth", "ldflags", "lddlflags" and "ldflags_nolargefiles" values
2341 in Config.pm and Config_heavy.pl were not previously being set
2342 correctly because, with that compiler, the include and lib
2343 directories are not immediately below "$(CCHOME)" (5.12.2).
2344 · The build process proceeds more smoothly with mingw and dmake when
2346 C:\MSYS\bin is in the PATH, due to a "Cwd" fix.
2347 · Support for building with Visual C++ 2010 is now underway, but is
2349 not yet complete. See README.win32 or perlwin32 for more details.
2350 · The option to use an externally-supplied crypt(), or to build with
2352 no crypt() at all, has been removed. Perl supplies its own crypt()
2353 implementation for Windows, and the political situation that
2354 required this part of the distribution to sometimes be omitted is
2355 long gone.
2356
2358 New APIs
2359 CLONE_PARAMS structure added to ease correct thread creation
2360 Modules that create threads should now create "CLONE_PARAMS" structures
2362 by calling the new function Perl_clone_params_new(), and free them with
2363 Perl_clone_params_del(). This will ensure compatibility with any
2364 future changes to the internals of the "CLONE_PARAMS" structure layout,
2365 and that it is correctly allocated and initialised.
2366 New parsing functions
2368 Several functions have been added for parsing Perl statements and
2370 expressions. These functions are meant to be used by XS code invoked
2371 during Perl parsing, in a recursive-descent manner, to allow modules to
2372 augment the standard Perl syntax.
2373 · parse_stmtseq() parses a sequence of statements, up to closing
2375 brace or EOF.
2376 · parse_fullstmt() parses a complete Perl statement, including
2378 optional label.
2379 · parse_barestmt() parses a statement without a label.
2381 · parse_block() parses a code block.
2383 · parse_label() parses a statement label, separate from statements.
2385 · "parse_fullexpr()", "parse_listexpr()", "parse_termexpr()", and
2387 "parse_arithexpr()" parse expressions at various precedence levels.
2388 Hints hash API
2390 A new C API for introspecting the hinthash "%^H" at runtime has been
2392 added. See "cop_hints_2hv", "cop_hints_fetchpvn",
2393 "cop_hints_fetchpvs", "cop_hints_fetchsv", and "hv_copy_hints_hv" in
2394 perlapi for details.
2395 A new, experimental API has been added for accessing the internal
2397 structure that Perl uses for "%^H". See the functions beginning with
2398 "cophh_" in perlapi.
2399 C interface to caller()
2401 The "caller_cx" function has been added as an XSUB-writer's equivalent
2403 of caller(). See perlapi for details.
2404 Custom per-subroutine check hooks
2406 XS code in an extension module can now annotate a subroutine (whether
2408 implemented in XS or in Perl) so that nominated XS code will be called
2409 at compile time (specifically as part of op checking) to change the op
2410 tree of that subroutine. The compile-time check function (supplied by
2411 the extension module) can implement argument processing that can't be
2412 expressed as a prototype, generate customised compile-time warnings,
2413 perform constant folding for a pure function, inline a subroutine
2414 consisting of sufficiently simple ops, replace the whole call with a
2415 custom op, and so on. This was previously all possible by hooking the
2416 "entersub" op checker, but the new mechanism makes it easy to tie the
2417 hook to a specific subroutine. See "cv_set_call_checker" in perlapi.
2418 To help in writing custom check hooks, several subtasks within standard
2420 "entersub" op checking have been separated out and exposed in the API.
2421 Improved support for custom OPs
2423 Custom ops can now be registered with the new "custom_op_register" C
2425 function and the "XOP" structure. This will make it easier to add new
2426 properties of custom ops in the future. Two new properties have been
2427 added already, "xop_class" and "xop_peep".
2428 "xop_class" is one of the OA_*OP constants. It allows B and other
2430 introspection mechanisms to work with custom ops that aren't BASEOPs.
2431 "xop_peep" is a pointer to a function that will be called for ops of
2432 this type from "Perl_rpeep".
2433 See "Custom Operators" in perlguts and "Custom Operators" in perlapi
2435 for more detail.
2436 The old "PL_custom_op_names"/"PL_custom_op_descs" interface is still
2438 supported but discouraged.
2439 Scope hooks
2441 It is now possible for XS code to hook into Perl's lexical scope
2443 mechanism at compile time, using the new "Perl_blockhook_register"
2444 function. See "Compile-time scope hooks" in perlguts.
2445 The recursive part of the peephole optimizer is now hookable
2447 In addition to "PL_peepp", for hooking into the toplevel peephole
2449 optimizer, a "PL_rpeepp" is now available to hook into the optimizer
2450 recursing into side-chains of the optree.
2451 New non-magical variants of existing functions
2453 The following functions/macros have been added to the API. The *_nomg
2455 macros are equivalent to their non-"_nomg" variants, except that they
2456 ignore get-magic. Those ending in "_flags" allow one to specify
2457 whether get-magic is processed.
2458 sv_2bool_flags
2460 SvTRUE_nomg
2461 sv_2nv_flags
2462 SvNV_nomg
2463 sv_cmp_flags
2464 sv_cmp_locale_flags
2465 sv_eq_flags
2466 sv_collxfrm_flags
2467 In some of these cases, the non-"_flags" functions have been replaced
2469 with wrappers around the new functions.
2470 pv/pvs/sv versions of existing functions
2472 Many functions ending with pvn now have equivalent "pv/pvs/sv"
2474 versions.
2475 List op-building functions
2477 List op-building functions have been added to the API. See
2479 op_append_elem, op_append_list, and op_prepend_elem in perlapi.
2480 "LINKLIST"
2482 The LINKLIST macro, part of op building that constructs the execution-
2484 order op chain, has been added to the API.
2485 Localisation functions
2487 The "save_freeop", "save_op", "save_pushi32ptr" and "save_pushptrptr"
2489 functions have been added to the API.
2490 Stash names
2492 A stash can now have a list of effective names in addition to its usual
2494 name. The first effective name can be accessed via the "HvENAME"
2495 macro, which is now the recommended name to use in MRO linearisations
2496 ("HvNAME" being a fallback if there is no "HvENAME").
2497 These names are added and deleted via "hv_ename_add" and
2499 "hv_ename_delete". These two functions are not part of the API.
2500 New functions for finding and removing magic
2502 The "mg_findext()" and "sv_unmagicext()" functions have been added to
2504 the API. They allow extension authors to find and remove magic
2505 attached to scalars based on both the magic type and the magic virtual
2506 table, similar to how sv_magicext() attaches magic of a certain type
2507 and with a given virtual table to a scalar. This eliminates the need
2508 for extensions to walk the list of "MAGIC" pointers of an "SV" to find
2509 the magic that belongs to them.
2510 "find_rundefsv"
2512 This function returns the SV representing $_, whether it's lexical or
2514 dynamic.
2515 "Perl_croak_no_modify"
2517 Perl_croak_no_modify() is short-hand for "Perl_croak("%s",
2519 PL_no_modify)".
2520 "PERL_STATIC_INLINE" define
2522 The "PERL_STATIC_INLINE" define has been added to provide the best-
2524 guess incantation to use for static inline functions, if the C compiler
2525 supports C99-style static inline. If it doesn't, it'll give a plain
2526 "static".
2527 "HAS_STATIC_INLINE" can be used to check if the compiler actually
2529 supports inline functions.
2530 New "pv_escape" option for hexadecimal escapes
2532 A new option, "PERL_PV_ESCAPE_NONASCII", has been added to "pv_escape"
2534 to dump all characters above ASCII in hexadecimal. Before, one could
2535 get all characters as hexadecimal or the Latin1 non-ASCII as octal.
2536 "lex_start"
2538 "lex_start" has been added to the API, but is considered experimental.
2540 op_scope() and op_lvalue()
2542 The op_scope() and op_lvalue() functions have been added to the API,
2544 but are considered experimental.
2545 C API Changes
2547 "PERL_POLLUTE" has been removed
2548 The option to define "PERL_POLLUTE" to expose older 5.005 symbols for
2550 backwards compatibility has been removed. Its use was always
2551 discouraged, and MakeMaker contains a more specific escape hatch:
2552 perl Makefile.PL POLLUTE=1
2554 This can be used for modules that have not been upgraded to 5.6 naming
2556 conventions (and really should be completely obsolete by now).
2557 Check API compatibility when loading XS modules
2559 When Perl's API changes in incompatible ways (which usually happens
2561 between major releases), XS modules compiled for previous versions of
2562 Perl will no longer work. They need to be recompiled against the new
2563 Perl.
2564 The "XS_APIVERSION_BOOTCHECK" macro has been added to ensure that
2566 modules are recompiled and to prevent users from accidentally loading
2567 modules compiled for old perls into newer perls. That macro, which is
2568 called when loading every newly compiled extension, compares the API
2569 version of the running perl with the version a module has been compiled
2570 for and raises an exception if they don't match.
2571 Perl_fetch_cop_label
2573 The first argument of the C API function "Perl_fetch_cop_label" has
2575 changed from "struct refcounted_he *" to "COP *", to insulate the user
2576 from implementation details.
2577 This API function was marked as "may change", and likely isn't in use
2579 outside the core. (Neither an unpacked CPAN nor Google's codesearch
2580 finds any other references to it.)
2581 GvCV() and GvGP() are no longer lvalues
2583 The new GvCV_set() and GvGP_set() macros are now provided to replace
2585 assignment to those two macros.
2586 This allows a future commit to eliminate some backref magic between GV
2588 and CVs, which will require complete control over assignment to the
2589 "gp_cv" slot.
2590 CvGV() is no longer an lvalue
2592 Under some circumstances, the CvGV() field of a CV is now reference-
2594 counted. To ensure consistent behaviour, direct assignment to it, for
2595 example "CvGV(cv) = gv" is now a compile-time error. A new macro,
2596 "CvGV_set(cv,gv)" has been introduced to run this operation safely.
2597 Note that modification of this field is not part of the public API,
2598 regardless of this new macro (and despite its being listed in this
2599 section).
2600 CvSTASH() is no longer an lvalue
2602 The CvSTASH() macro can now only be used as an rvalue. CvSTASH_set()
2604 has been added to replace assignment to CvSTASH(). This is to ensure
2605 that backreferences are handled properly. These macros are not part of
2606 the API.
2607 Calling conventions for "newFOROP" and "newWHILEOP"
2609 The way the parser handles labels has been cleaned up and refactored.
2611 As a result, the newFOROP() constructor function no longer takes a
2612 parameter stating what label is to go in the state op.
2613 The newWHILEOP() and newFOROP() functions no longer accept a line
2615 number as a parameter.
2616 Flags passed to "uvuni_to_utf8_flags" and "utf8n_to_uvuni"
2618 Some of the flags parameters to uvuni_to_utf8_flags() and
2620 utf8n_to_uvuni() have changed. This is a result of Perl's now allowing
2621 internal storage and manipulation of code points that are problematic
2622 in some situations. Hence, the default actions for these functions has
2623 been complemented to allow these code points. The new flags are
2624 documented in perlapi. Code that requires the problematic code points
2625 to be rejected needs to change to use the new flags. Some flag names
2626 are retained for backward source compatibility, though they do nothing,
2627 as they are now the default. However the flags "UNICODE_ALLOW_FDD0",
2628 "UNICODE_ALLOW_FFFF", "UNICODE_ILLEGAL", and "UNICODE_IS_ILLEGAL" have
2629 been removed, as they stem from a fundamentally broken model of how the
2630 Unicode non-character code points should be handled, which is now
2631 described in "Non-character code points" in perlunicode. See also the
2632 Unicode section under "Selected Bug Fixes".
2633 Deprecated C APIs
2635 "Perl_ptr_table_clear"
2636 "Perl_ptr_table_clear" is no longer part of Perl's public API.
2637 Calling it now generates a deprecation warning, and it will be
2638 removed in a future release.
2639 "sv_compile_2op"
2641 The sv_compile_2op() API function is now deprecated. Searches
2642 suggest that nothing on CPAN is using it, so this should have zero
2643 impact.
2644 It attempted to provide an API to compile code down to an optree,
2646 but failed to bind correctly to lexicals in the enclosing scope.
2647 It's not possible to fix this problem within the constraints of its
2648 parameters and return value.
2649 "find_rundefsvoffset"
2651 The "find_rundefsvoffset" function has been deprecated. It
2652 appeared that its design was insufficient for reliably getting the
2653 lexical $_ at run-time.
2654 Use the new "find_rundefsv" function or the "UNDERBAR" macro
2656 instead. They directly return the right SV representing $_,
2657 whether it's lexical or dynamic.
2658 "CALL_FPTR" and "CPERLscope"
2660 Those are left from an old implementation of "MULTIPLICITY" using
2661 C++ objects, which was removed in Perl 5.8. Nowadays these macros
2662 do exactly nothing, so they shouldn't be used anymore.
2663 For compatibility, they are still defined for external "XS" code.
2665 Only extensions defining "PERL_CORE" must be updated now.
2666 Other Internal Changes
2668 Stack unwinding
2669 The protocol for unwinding the C stack at the last stage of a "die" has
2671 changed how it identifies the target stack frame. This now uses a
2672 separate variable "PL_restartjmpenv", where previously it relied on the
2673 "blk_eval.cur_top_env" pointer in the "eval" context frame that has
2674 nominally just been discarded. This change means that code running
2675 during various stages of Perl-level unwinding no longer needs to take
2676 care to avoid destroying the ghost frame.
2677 Scope stack entries
2679 The format of entries on the scope stack has been changed, resulting in
2681 a reduction of memory usage of about 10%. In particular, the memory
2682 used by the scope stack to record each active lexical variable has been
2683 halved.
2684 Memory allocation for pointer tables
2686 Memory allocation for pointer tables has been changed. Previously
2688 "Perl_ptr_table_store" allocated memory from the same arena system as
2689 "SV" bodies and "HE"s, with freed memory remaining bound to those
2690 arenas until interpreter exit. Now it allocates memory from arenas
2691 private to the specific pointer table, and that memory is returned to
2692 the system when "Perl_ptr_table_free" is called. Additionally,
2693 allocation and release are both less CPU intensive.
2694 "UNDERBAR"
2696 The "UNDERBAR" macro now calls "find_rundefsv". "dUNDERBAR" is now a
2698 noop but should still be used to ensure past and future compatibility.
2699 String comparison routines renamed
2701 The "ibcmp_*" functions have been renamed and are now called "foldEQ",
2703 "foldEQ_locale", and "foldEQ_utf8". The old names are still available
2704 as macros.
2705 "chop" and "chomp" implementations merged
2707 The opcode bodies for "chop" and "chomp" and for "schop" and "schomp"
2709 have been merged. The implementation functions Perl_do_chop() and
2710 Perl_do_chomp(), never part of the public API, have been merged and
2711 moved to a static function in pp.c. This shrinks the Perl binary
2712 slightly, and should not affect any code outside the core (unless it is
2713 relying on the order of side-effects when "chomp" is passed a list of
2714 values).
2715
2717 I/O
2718 · Perl no longer produces this warning:
2719 $ perl -we 'open(my $f, ">", \my $x); binmode($f, "scalar")'
2721 Use of uninitialized value in binmode at -e line 1.
2722 · Opening a glob reference via "open($fh, ">", \*glob)" no longer
2724 causes the glob to be corrupted when the filehandle is printed to.
2725 This would cause Perl to crash whenever the glob's contents were
2726 accessed [perl #77492].
2727 · PerlIO no longer crashes when called recursively, such as from a
2729 signal handler. Now it just leaks memory [perl #75556].
2730 · Most I/O functions were not warning for unopened handles unless the
2732 "closed" and "unopened" warnings categories were both enabled. Now
2733 only "use warnings 'unopened'" is necessary to trigger these
2734 warnings, as had always been the intention.
2735 · There have been several fixes to PerlIO layers:
2737 When "binmode(FH, ":crlf")" pushes the ":crlf" layer on top of the
2739 stack, it no longer enables crlf layers lower in the stack so as to
2740 avoid unexpected results [perl #38456].
2741 Opening a file in ":raw" mode now does what it advertises to do
2743 (first open the file, then "binmode" it), instead of simply leaving
2744 off the top layer [perl #80764].
2745 The three layers ":pop", ":utf8", and ":bytes" didn't allow
2747 stacking when opening a file. For example this:
2748 open(FH, ">:pop:perlio", "some.file") or die $!;
2750 would throw an "Invalid argument" error. This has been fixed in
2752 this release [perl #82484].
2753 Regular Expression Bug Fixes
2755 · The regular expression engine no longer loops when matching
2756 ""\N{LATIN SMALL LIGATURE FF}" =~ /f+/i" and similar expressions
2757 [perl #72998] (5.12.1).
2758 · The trie runtime code should no longer allocate massive amounts of
2760 memory, fixing #74484.
2761 · Syntax errors in "(?{...})" blocks no longer cause panic messages
2763 [perl #2353].
2764 · A pattern like "(?:(o){2})?" no longer causes a "panic" error [perl
2766 #39233].
2767 · A fatal error in regular expressions containing "(.*?)" when
2769 processing UTF-8 data has been fixed [perl #75680] (5.12.2).
2770 · An erroneous regular expression engine optimisation that caused
2772 regex verbs like *COMMIT sometimes to be ignored has been removed.
2773 · The regular expression bracketed character class "[\8\9]" was
2775 effectively the same as "[89\000]", incorrectly matching a NULL
2776 character. It also gave incorrect warnings that the 8 and 9 were
2777 ignored. Now "[\8\9]" is the same as "[89]" and gives legitimate
2778 warnings that "\8" and "\9" are unrecognized escape sequences,
2779 passed-through.
2780 · A regular expression match in the right-hand side of a global
2782 substitution ("s///g") that is in the same scope will no longer
2783 cause match variables to have the wrong values on subsequent
2784 iterations. This can happen when an array or hash subscript is
2785 interpolated in the right-hand side, as in "s|(.)|@a{ print($1),
2786 /./ }|g" [perl #19078].
2787 · Several cases in which characters in the Latin-1 non-ASCII range
2789 (0x80 to 0xFF) used not to match themselves, or used to match both
2790 a character class and its complement, have been fixed. For
2791 instance, U+00E2 could match both "\w" and "\W" [perl #78464] [perl
2792 #18281] [perl #60156].
2793 · Matching a Unicode character against an alternation containing
2795 characters that happened to match continuation bytes in the
2796 former's UTF8 representation (like "qq{\x{30ab}} =~ /\xab|\xa9/")
2797 would cause erroneous warnings [perl #70998].
2798 · The trie optimisation was not taking empty groups into account,
2800 preventing "foo" from matching "/\A(?:(?:)foo|bar|zot)\z/" [perl
2801 #78356].
2802 · A pattern containing a "+" inside a lookahead would sometimes cause
2804 an incorrect match failure in a global match (for example,
2805 "/(?=(\S+))/g") [perl #68564].
2806 · A regular expression optimisation would sometimes cause a match
2808 with a "{n,m}" quantifier to fail when it should have matched [perl
2809 #79152].
2810 · Case-insensitive matching in regular expressions compiled under
2812 "use locale" now works much more sanely when the pattern or target
2813 string is internally encoded in UTF8. Previously, under these
2814 conditions the localeness was completely lost. Now, code points
2815 above 255 are treated as Unicode, but code points between 0 and 255
2816 are treated using the current locale rules, regardless of whether
2817 the pattern or the string is encoded in UTF8. The few case-
2818 insensitive matches that cross the 255/256 boundary are not
2819 allowed. For example, 0xFF does not caselessly match the character
2820 at 0x178, LATIN CAPITAL LETTER Y WITH DIAERESIS, because 0xFF may
2821 not be LATIN SMALL LETTER Y in the current locale, and Perl has no
2822 way of knowing if that character even exists in the locale, much
2823 less what code point it is.
2824 · The "(?|...)" regular expression construct no longer crashes if the
2826 final branch has more sets of capturing parentheses than any other
2827 branch. This was fixed in Perl 5.10.1 for the case of a single
2828 branch, but that fix did not take multiple branches into account
2829 [perl #84746].
2830 · A bug has been fixed in the implementation of "{...}" quantifiers
2832 in regular expressions that prevented the code block in "/((\w+)(?{
2833 print $2 })){2}/" from seeing the $2 sometimes [perl #84294].
2834 Syntax/Parsing Bugs
2836 · "when (scalar) {...}" no longer crashes, but produces a syntax
2837 error [perl #74114] (5.12.1).
2838 · A label right before a string eval ("foo: eval $string") no longer
2840 causes the label to be associated also with the first statement
2841 inside the eval [perl #74290] (5.12.1).
2842 · The "no 5.13.2" form of "no" no longer tries to turn on features or
2844 pragmata (like strict) [perl #70075] (5.12.2).
2845 · "BEGIN {require 5.12.0}" now behaves as documented, rather than
2847 behaving identically to "use 5.12.0". Previously, "require" in a
2848 "BEGIN" block was erroneously executing the "use feature ':5.12.0'"
2849 and "use strict" behaviour, which only "use" was documented to
2850 provide [perl #69050].
2851 · A regression introduced in Perl 5.12.0, making "my $x = 3; $x =
2853 length(undef)" result in $x set to 3 has been fixed. $x will now
2854 be "undef" [perl #85508] (5.12.2).
2855 · When strict "refs" mode is off, "%{...}" in rvalue context returns
2857 "undef" if its argument is undefined. An optimisation introduced
2858 in Perl 5.12.0 to make "keys %{...}" faster when used as a boolean
2859 did not take this into account, causing "keys %{+undef}" (and "keys
2860 %$foo" when $foo is undefined) to be an error, which it should be
2861 so in strict mode only [perl #81750].
2862 · Constant-folding used to cause
2864 $text =~ ( 1 ? /phoo/ : /bear/)
2866 to turn into
2868 $text =~ /phoo/
2870 at compile time. Now it correctly matches against $_ [perl
2872 #20444].
2873 · Parsing Perl code (either with string "eval" or by loading modules)
2875 from within a "UNITCHECK" block no longer causes the interpreter to
2876 crash [perl #70614].
2877 · String "eval"s no longer fail after 2 billion scopes have been
2879 compiled [perl #83364].
2880 · The parser no longer hangs when encountering certain Unicode
2882 characters, such as U+387 [perl #74022].
2883 · Defining a constant with the same name as one of Perl's special
2885 blocks (like "INIT") stopped working in 5.12.0, but has now been
2886 fixed [perl #78634].
2887 · A reference to a literal value used as a hash key ($hash{\"foo"})
2889 used to be stringified, even if the hash was tied [perl #79178].
2890 · A closure containing an "if" statement followed by a constant or
2892 variable is no longer treated as a constant [perl #63540].
2893 · "state" can now be used with attributes. It used to mean the same
2895 thing as "my" if any attributes were present [perl #68658].
2896 · Expressions like "@$a > 3" no longer cause $a to be mentioned in
2898 the "Use of uninitialized value in numeric gt" warning when $a is
2899 undefined (since it is not part of the ">" expression, but the
2900 operand of the "@") [perl #72090].
2901 · Accessing an element of a package array with a hard-coded number
2903 (as opposed to an arbitrary expression) would crash if the array
2904 did not exist. Usually the array would be autovivified during
2905 compilation, but typeglob manipulation could remove it, as in these
2906 two cases which used to crash:
2907 *d = *a; print $d[0];
2909 undef *d; print $d[0];
2910 · The -C command-line option, when used on the shebang line, can now
2912 be followed by other options [perl #72434].
2913 · The "B" module was returning "B::OP"s instead of "B::LOGOP"s for
2915 "entertry" [perl #80622]. This was due to a bug in the Perl core,
2916 not in "B" itself.
2917 Stashes, Globs and Method Lookup
2919 Perl 5.10.0 introduced a new internal mechanism for caching MROs
2920 (method resolution orders, or lists of parent classes; aka "isa"
2921 caches) to make method lookup faster (so @ISA arrays would not have to
2922 be searched repeatedly). Unfortunately, this brought with it quite a
2923 few bugs. Almost all of these have been fixed now, along with a few
2924 MRO-related bugs that existed before 5.10.0:
2925 · The following used to have erratic effects on method resolution,
2927 because the "isa" caches were not reset or otherwise ended up
2928 listing the wrong classes. These have been fixed.
2929 Aliasing packages by assigning to globs [perl #77358]
2931 Deleting packages by deleting their containing stash elements
2932 Undefining the glob containing a package ("undef *Foo::")
2933 Undefining an ISA glob ("undef *Foo::ISA")
2934 Deleting an ISA stash element ("delete $Foo::{ISA}")
2935 Sharing @ISA arrays between classes (via "*Foo::ISA = \@Bar::ISA"
2936 or "*Foo::ISA = *Bar::ISA") [perl #77238]
2937 "undef *Foo::ISA" would even stop a new @Foo::ISA array from
2939 updating caches.
2940 · Typeglob assignments would crash if the glob's stash no longer
2942 existed, so long as the glob assigned to were named "ISA" or the
2943 glob on either side of the assignment contained a subroutine.
2944 · "PL_isarev", which is accessible to Perl via "mro::get_isarev" is
2946 now updated properly when packages are deleted or removed from the
2947 @ISA of other classes. This allows many packages to be created and
2948 deleted without causing a memory leak [perl #75176].
2949 In addition, various other bugs related to typeglobs and stashes have
2951 been fixed:
2952 · Some work has been done on the internal pointers that link between
2954 symbol tables (stashes), typeglobs, and subroutines. This has the
2955 effect that various edge cases related to deleting stashes or stash
2956 entries (for example, <%FOO:: = ()>), and complex typeglob or code-
2957 reference aliasing, will no longer crash the interpreter.
2958 · Assigning a reference to a glob copy now assigns to a glob slot
2960 instead of overwriting the glob with a scalar [perl #1804] [perl
2961 #77508].
2962 · A bug when replacing the glob of a loop variable within the loop
2964 has been fixed [perl #21469]. This means the following code will
2965 no longer crash:
2966 for $x (...) {
2968 *x = *y;
2969 }
2970 · Assigning a glob to a PVLV used to convert it to a plain string.
2972 Now it works correctly, and a PVLV can hold a glob. This would
2973 happen when a nonexistent hash or array element was passed to a
2974 subroutine:
2975 sub { $_[0] = *foo }->($hash{key});
2977 # $_[0] would have been the string "*main::foo"
2978 It also happened when a glob was assigned to, or returned from, an
2980 element of a tied array or hash [perl #36051].
2981 · When trying to report "Use of uninitialized value $Foo::BAR",
2983 crashes could occur if the glob holding the global variable in
2984 question had been detached from its original stash by, for example,
2985 "delete $::{"Foo::"}". This has been fixed by disabling the
2986 reporting of variable names in those cases.
2987 · During the restoration of a localised typeglob on scope exit, any
2989 destructors called as a result would be able to see the typeglob in
2990 an inconsistent state, containing freed entries, which could result
2991 in a crash. This would affect code like this:
2992 local *@;
2994 eval { die bless [] }; # puts an object in $@
2995 sub DESTROY {
2996 local $@; # boom
2997 }
2998 Now the glob entries are cleared before any destructors are called.
3000 This also means that destructors can vivify entries in the glob.
3001 So Perl tries again and, if the entries are re-created too many
3002 times, dies with a "panic: gp_free ..." error message.
3003 · If a typeglob is freed while a subroutine attached to it is still
3005 referenced elsewhere, the subroutine is renamed to "__ANON__" in
3006 the same package, unless the package has been undefined, in which
3007 case the "__ANON__" package is used. This could cause packages to
3008 be sometimes autovivified, such as if the package had been deleted.
3009 Now this no longer occurs. The "__ANON__" package is also now used
3010 when the original package is no longer attached to the symbol
3011 table. This avoids memory leaks in some cases [perl #87664].
3012 · Subroutines and package variables inside a package whose name ends
3014 with "::" can now be accessed with a fully qualified name.
3015 Unicode
3017 · What has become known as "the Unicode Bug" is almost completely
3018 resolved in this release. Under "use feature 'unicode_strings'"
3019 (which is automatically selected by "use 5.012" and above), the
3020 internal storage format of a string no longer affects the external
3021 semantics. [perl #58182].
3022 There are two known exceptions:
3024 1. The now-deprecated, user-defined case-changing functions
3026 require utf8-encoded strings to operate. The CPAN module
3027 Unicode::Casing has been written to replace this feature
3028 without its drawbacks, and the feature is scheduled to be
3029 removed in 5.16.
3030 2. quotemeta() (and its in-line equivalent "\Q") can also give
3032 different results depending on whether a string is encoded in
3033 UTF-8. See "The "Unicode Bug"" in perlunicode.
3034 · Handling of Unicode non-character code points has changed.
3036 Previously they were mostly considered illegal, except that in some
3037 place only one of the 66 of them was known. The Unicode Standard
3038 considers them all legal, but forbids their "open interchange".
3039 This is part of the change to allow internal use of any code point
3040 (see "Core Enhancements"). Together, these changes resolve [perl
3041 #38722], [perl #51918], [perl #51936], and [perl #63446].
3042 · Case-insensitive "/i" regular expression matching of Unicode
3044 characters that match multiple characters now works much more as
3045 intended. For example
3046 "\N{LATIN SMALL LIGATURE FFI}" =~ /ffi/ui
3048 and
3050 "ffi" =~ /\N{LATIN SMALL LIGATURE FFI}/ui
3052 are both true. Previously, there were many bugs with this feature.
3054 What hasn't been fixed are the places where the pattern contains
3055 the multiple characters, but the characters are split up by other
3056 things, such as in
3057 "\N{LATIN SMALL LIGATURE FFI}" =~ /(f)(f)i/ui
3059 or
3061 "\N{LATIN SMALL LIGATURE FFI}" =~ /ffi*/ui
3063 or
3065 "\N{LATIN SMALL LIGATURE FFI}" =~ /[a-f][f-m][g-z]/ui
3067 None of these match.
3069 Also, this matching doesn't fully conform to the current Unicode
3071 Standard, which asks that the matching be made upon the NFD
3072 (Normalization Form Decomposed) of the text. However, as of this
3073 writing (April 2010), the Unicode Standard is currently in flux
3074 about what they will recommend doing with regard in such scenarios.
3075 It may be that they will throw out the whole concept of multi-
3076 character matches. [perl #71736].
3077 · Naming a deprecated character in "\N{NAME}" no longer leaks memory.
3079 · We fixed a bug that could cause "\N{NAME}" constructs followed by a
3081 single "." to be parsed incorrectly [perl #74978] (5.12.1).
3082 · "chop" now correctly handles characters above "\x{7fffffff}" [perl
3084 #73246].
3085 · Passing to "index" an offset beyond the end of the string when the
3087 string is encoded internally in UTF8 no longer causes panics [perl
3088 #75898].
3089 · warn() and die() now respect utf8-encoded scalars [perl #45549].
3091 · Sometimes the UTF8 length cache would not be reset on a value
3093 returned by substr, causing "length(substr($uni_string, ...))" to
3094 give wrong answers. With "${^UTF8CACHE}" set to -1, it would also
3095 produce a "panic" error message [perl #77692].
3096 Ties, Overloading and Other Magic
3098 · Overloading now works properly in conjunction with tied variables.
3099 What formerly happened was that most ops checked their arguments
3100 for overloading before checking for magic, so for example an
3101 overloaded object returned by a tied array access would usually be
3102 treated as not overloaded [RT #57012].
3103 · Various instances of magic (like tie methods) being called on tied
3105 variables too many or too few times have been fixed:
3106 · "$tied->()" did not always call FETCH [perl #8438].
3108 · Filetest operators and "y///" and "tr///" were calling FETCH
3110 too many times.
3111 · The "=" operator used to ignore magic on its right-hand side if
3113 the scalar happened to hold a typeglob (if a typeglob was the
3114 last thing returned from or assigned to a tied scalar) [perl
3115 #77498].
3116 · Dereference operators used to ignore magic if the argument was
3118 a reference already (such as from a previous FETCH) [perl
3119 #72144].
3120 · "splice" now calls set-magic (so changes made by "splice @ISA"
3122 are respected by method calls) [perl #78400].
3123 · In-memory files created by "open($fh, ">", \$buffer)" were not
3125 calling FETCH/STORE at all [perl #43789] (5.12.2).
3126 · utf8::is_utf8() now respects get-magic (like $1) (5.12.1).
3128 · Non-commutative binary operators used to swap their operands if the
3130 same tied scalar was used for both operands and returned a
3131 different value for each FETCH. For instance, if $t returned 2 the
3132 first time and 3 the second, then "$t/$t" would evaluate to 1.5.
3133 This has been fixed [perl #87708].
3134 · String "eval" now detects taintedness of overloaded or tied
3136 arguments [perl #75716].
3137 · String "eval" and regular expression matches against objects with
3139 string overloading no longer cause memory corruption or crashes
3140 [perl #77084].
3141 · readline now honors "<>" overloading on tied arguments.
3143 · "<expr>" always respects overloading now if the expression is
3145 overloaded.
3146 Because "<> as glob" was parsed differently from "<> as filehandle"
3148 from 5.6 onwards, something like "<$foo[0]>" did not handle
3149 overloading, even if $foo[0] was an overloaded object. This was
3150 contrary to the documentation for overload, and meant that "<>"
3151 could not be used as a general overloaded iterator operator.
3152 · The fallback behaviour of overloading on binary operators was
3154 asymmetric [perl #71286].
3155 · Magic applied to variables in the main package no longer affects
3157 other packages. See "Magic variables outside the main package"
3158 above [perl #76138].
3159 · Sometimes magic (ties, taintedness, etc.) attached to variables
3161 could cause an object to last longer than it should, or cause a
3162 crash if a tied variable were freed from within a tie method.
3163 These have been fixed [perl #81230].
3164 · DESTROY methods of objects implementing ties are no longer able to
3166 crash by accessing the tied variable through a weak reference [perl
3167 #86328].
3168 · Fixed a regression of kill() when a match variable is used for the
3170 process ID to kill [perl #75812].
3171 · $AUTOLOAD used to remain tainted forever if it ever became tainted.
3173 Now it is correctly untainted if an autoloaded method is called and
3174 the method name was not tainted.
3175 · "sprintf" now dies when passed a tainted scalar for the format. It
3177 did already die for arbitrary expressions, but not for simple
3178 scalars [perl #82250].
3179 · "lc", "uc", "lcfirst", and "ucfirst" no longer return untainted
3181 strings when the argument is tainted. This has been broken since
3182 perl 5.8.9 [perl #87336].
3183 The Debugger
3185 · The Perl debugger now also works in taint mode [perl #76872].
3186 · Subroutine redefinition works once more in the debugger [perl
3188 #48332].
3189 · When -d is used on the shebang ("#!") line, the debugger now has
3191 access to the lines of the main program. In the past, this
3192 sometimes worked and sometimes did not, depending on the order in
3193 which things happened to be arranged in memory [perl #71806].
3194 · A possible memory leak when using caller() to set @DB::args has
3196 been fixed (5.12.2).
3197 · Perl no longer stomps on $DB::single, $DB::trace, and $DB::signal
3199 if these variables already have values when $^P is assigned to
3200 [perl #72422].
3201 · "#line" directives in string evals were not properly updating the
3203 arrays of lines of code ("@{"_< ..."}") that the debugger (or any
3204 debugging or profiling module) uses. In threaded builds, they were
3205 not being updated at all. In non-threaded builds, the line number
3206 was ignored, so any change to the existing line number would cause
3207 the lines to be misnumbered [perl #79442].
3208 Threads
3210 · Perl no longer accidentally clones lexicals in scope within active
3211 stack frames in the parent when creating a child thread [perl
3212 #73086].
3213 · Several memory leaks in cloning and freeing threaded Perl
3215 interpreters have been fixed [perl #77352].
3216 · Creating a new thread when directory handles were open used to
3218 cause a crash, because the handles were not cloned, but simply
3219 passed to the new thread, resulting in a double free.
3220 Now directory handles are cloned properly on Windows and on systems
3222 that have a "fchdir" function. On other systems, new threads
3223 simply do not inherit directory handles from their parent threads
3224 [perl #75154].
3225 · The typeglob "*,", which holds the scalar variable $, (output field
3227 separator), had the wrong reference count in child threads.
3228 · [perl #78494] When pipes are shared between threads, the "close"
3230 function (and any implicit close, such as on thread exit) no longer
3231 blocks.
3232 · Perl now does a timely cleanup of SVs that are cloned into a new
3234 thread but then discovered to be orphaned (that is, their owners
3235 are not cloned). This eliminates several "scalars leaked" warnings
3236 when joining threads.
3237 Scoping and Subroutines
3239 · Lvalue subroutines are again able to return copy-on-write scalars.
3240 This had been broken since version 5.10.0 [perl #75656] (5.12.3).
3241 · "require" no longer causes "caller" to return the wrong file name
3243 for the scope that called "require" and other scopes higher up that
3244 had the same file name [perl #68712].
3245 · "sort" with a "($$)"-prototyped comparison routine used to cause
3247 the value of @_ to leak out of the sort. Taking a reference to @_
3248 within the sorting routine could cause a crash [perl #72334].
3249 · Match variables (like $1) no longer persist between calls to a sort
3251 subroutine [perl #76026].
3252 · Iterating with "foreach" over an array returned by an lvalue sub
3254 now works [perl #23790].
3255 · $@ is now localised during calls to "binmode" to prevent action at
3257 a distance [perl #78844].
3258 · Calling a closure prototype (what is passed to an attribute handler
3260 for a closure) now results in a "Closure prototype called" error
3261 message instead of a crash [perl #68560].
3262 · Mentioning a read-only lexical variable from the enclosing scope in
3264 a string "eval" no longer causes the variable to become writable
3265 [perl #19135].
3266 Signals
3268 · Within signal handlers, $! is now implicitly localized.
3269 · CHLD signals are no longer unblocked after a signal handler is
3271 called if they were blocked before by "POSIX::sigprocmask" [perl
3272 #82040].
3273 · A signal handler called within a signal handler could cause leaks
3275 or double-frees. Now fixed [perl #76248].
3276 Miscellaneous Memory Leaks
3278 · Several memory leaks when loading XS modules were fixed (5.12.2).
3279 · substr(), pos(), keys(), and vec() could, when used in combination
3281 with lvalues, result in leaking the scalar value they operate on,
3282 and cause its destruction to happen too late. This has now been
3283 fixed.
3284 · The postincrement and postdecrement operators, "++" and "--", used
3286 to cause leaks when used on references. This has now been fixed.
3287 · Nested "map" and "grep" blocks no longer leak memory when
3289 processing large lists [perl #48004].
3290 · "use VERSION" and "no VERSION" no longer leak memory [perl #78436]
3292 [perl #69050].
3293 · ".=" followed by "<>" or "readline" would leak memory if $/
3295 contained characters beyond the octet range and the scalar assigned
3296 to happened to be encoded as UTF8 internally [perl #72246].
3297 · "eval 'BEGIN{die}'" no longer leaks memory on non-threaded builds.
3299 Memory Corruption and Crashes
3301 · glob() no longer crashes when %File::Glob:: is empty and
3302 "CORE::GLOBAL::glob" isn't present [perl #75464] (5.12.2).
3303 · readline() has been fixed when interrupted by signals so it no
3305 longer returns the "same thing" as before or random memory.
3306 · When assigning a list with duplicated keys to a hash, the
3308 assignment used to return garbage and/or freed values:
3309 @a = %h = (list with some duplicate keys);
3311 This has now been fixed [perl #31865].
3313 · The mechanism for freeing objects in globs used to leave dangling
3315 pointers to freed SVs, meaning Perl users could see corrupted state
3316 during destruction.
3317 Perl now frees only the affected slots of the GV, rather than
3319 freeing the GV itself. This makes sure that there are no dangling
3320 refs or corrupted state during destruction.
3321 · The interpreter no longer crashes when freeing deeply-nested arrays
3323 of arrays. Hashes have not been fixed yet [perl #44225].
3324 · Concatenating long strings under "use encoding" no longer causes
3326 Perl to crash [perl #78674].
3327 · Calling "->import" on a class lacking an import method could
3329 corrupt the stack, resulting in strange behaviour. For instance,
3330 push @a, "foo", $b = bar->import;
3332 would assign "foo" to $b [perl #63790].
3334 · The "recv" function could crash when called with the MSG_TRUNC flag
3336 [perl #75082].
3337 · "formline" no longer crashes when passed a tainted format picture.
3339 It also taints $^A now if its arguments are tainted [perl #79138].
3340 · A bug in how we process filetest operations could cause a segfault.
3342 Filetests don't always expect an op on the stack, so we now use
3343 TOPs only if we're sure that we're not "stat"ing the "_"
3344 filehandle. This is indicated by "OPf_KIDS" (as checked in
3345 ck_ftst) [perl #74542] (5.12.1).
3346 · unpack() now handles scalar context correctly for %32H and %32u,
3348 fixing a potential crash. split() would crash because the third
3349 item on the stack wasn't the regular expression it expected.
3350 "unpack("%2H", ...)" would return both the unpacked result and the
3351 checksum on the stack, as would "unpack("%2u", ...)" [perl #73814]
3352 (5.12.2).
3353 Fixes to Various Perl Operators
3355 · The "&", "|", and "^" bitwise operators no longer coerce read-only
3356 arguments [perl #20661].
3357 · Stringifying a scalar containing "-0.0" no longer has the effect of
3359 turning false into true [perl #45133].
3360 · Some numeric operators were converting integers to floating point,
3362 resulting in loss of precision on 64-bit platforms [perl #77456].
3363 · sprintf() was ignoring locales when called with constant arguments
3365 [perl #78632].
3366 · Combining the vector (%v) flag and dynamic precision would cause
3368 "sprintf" to confuse the order of its arguments, making it treat
3369 the string as the precision and vice-versa [perl #83194].
3370 Bugs Relating to the C API
3372 · The C-level "lex_stuff_pvn" function would sometimes cause a
3373 spurious syntax error on the last line of the file if it lacked a
3374 final semicolon [perl #74006] (5.12.1).
3375 · The "eval_sv" and "eval_pv" C functions now set $@ correctly when
3377 there is a syntax error and no "G_KEEPERR" flag, and never set it
3378 if the "G_KEEPERR" flag is present [perl #3719].
3379 · The XS multicall API no longer causes subroutines to lose reference
3381 counts if called via the multicall interface from within those very
3382 subroutines. This affects modules like List::Util. Calling one of
3383 its functions with an active subroutine as the first argument could
3384 cause a crash [perl #78070].
3385 · The "SvPVbyte" function available to XS modules now calls magic
3387 before downgrading the SV, to avoid warnings about wide characters
3388 [perl #72398].
3389 · The ref types in the typemap for XS bindings now support magical
3391 variables [perl #72684].
3392 · "sv_catsv_flags" no longer calls "mg_get" on its second argument
3394 (the source string) if the flags passed to it do not include
3395 SV_GMAGIC. So it now matches the documentation.
3396 · "my_strftime" no longer leaks memory. This fixes a memory leak in
3398 "POSIX::strftime" [perl #73520].
3399 · XSUB.h now correctly redefines fgets under PERL_IMPLICIT_SYS [perl
3401 #55049] (5.12.1).
3402 · XS code using fputc() or fputs() on Windows could cause an error
3404 due to their arguments being swapped [perl #72704] (5.12.1).
3405 · A possible segfault in the "T_PTROBJ" default typemap has been
3407 fixed (5.12.2).
3408 · A bug that could cause "Unknown error" messages when "call_sv(code,
3410 G_EVAL)" is called from an XS destructor has been fixed (5.12.2).
3411
3413 This is a list of significant unresolved issues which are regressions
3414 from earlier versions of Perl or which affect widely-used CPAN modules.
3415 · "List::Util::first" misbehaves in the presence of a lexical $_
3417 (typically introduced by "my $_" or implicitly by "given"). The
3418 variable that gets set for each iteration is the package variable
3419 $_, not the lexical $_.
3420 A similar issue may occur in other modules that provide functions
3422 which take a block as their first argument, like
3423 foo { ... $_ ...} list
3425 See also: <http://rt.perl.org/rt3/Public/Bug/Display.html?id=67694>
3427 · readline() returns an empty string instead of a cached previous
3429 value when it is interrupted by a signal
3430 · The changes in prototype handling break Switch. A patch has been
3432 sent upstream and will hopefully appear on CPAN soon.
3433 · The upgrade to ExtUtils-MakeMaker-6.57_05 has caused some tests in
3435 the Module-Install distribution on CPAN to fail. (Specifically,
3436 02_mymeta.t tests 5 and 21; 18_all_from.t tests 6 and 15;
3437 19_authors.t tests 5, 13, 21, and 29; and
3438 20_authors_with_special_characters.t tests 6, 15, and 23 in version
3439 1.00 of that distribution now fail.)
3440 · On VMS, "Time::HiRes" tests will fail due to a bug in the CRTL's
3442 implementation of "setitimer": previous timer values would be
3443 cleared if a timer expired but not if the timer was reset before
3444 expiring. HP OpenVMS Engineering have corrected the problem and
3445 will release a patch in due course (Quix case # QXCM1001115136).
3446 · On VMS, there were a handful of "Module::Build" test failures we
3448 didn't get to before the release; please watch CPAN for updates.
3449
3451 keys(), values(), and each() work on arrays
3452 You can now use the keys(), values(), and each() builtins on arrays;
3453 previously you could use them only on hashes. See perlfunc for
3454 details. This is actually a change introduced in perl 5.12.0, but it
3455 was missed from that release's perl5120delta.
3456 split() and @_
3458 split() no longer modifies @_ when called in scalar or void context.
3459 In void context it now produces a "Useless use of split" warning. This
3460 was also a perl 5.12.0 change that missed the perldelta.
3461
3463 Randy Kobes, creator of http://kobesearch.cpan.org/ and
3464 contributor/maintainer to several core Perl toolchain modules, passed
3465 away on September 18, 2010 after a battle with lung cancer. The
3466 community was richer for his involvement. He will be missed.
3467
3469 Perl 5.14.0 represents one year of development since Perl 5.12.0 and
3470 contains nearly 550,000 lines of changes across nearly 3,000 files from
3471 150 authors and committers.
3472 Perl continues to flourish into its third decade thanks to a vibrant
3474 community of users and developers. The following people are known to
3475 have contributed the improvements that became Perl 5.14.0:
3476 Aaron Crane, Abhijit Menon-Sen, Abigail, var Arnfjoerd` Bjarmason,
3478 Alastair Douglas, Alexander Alekseev, Alexander Hartmaier, Alexandr
3479 Ciornii, Alex Davies, Alex Vandiver, Ali Polatel, Allen Smith, Andreas
3480 Koenig, Andrew Rodland, Andy Armstrong, Andy Dougherty, Aristotle
3481 Pagaltzis, Arkturuz, Arvan, A. Sinan Unur, Ben Morrow, Bo Lindbergh,
3482 Boris Ratner, Brad Gilbert, Bram, brian d foy, Brian Phillips, Casey
3483 West, Charles Bailey, Chas. Owens, Chip Salzenberg, Chris 'BinGOs'
3484 Williams, chromatic, Craig A. Berry, Curtis Jewell, Dagfinn Ilmari
3485 Mannsaaker, Dan Dascalescu, Dave Rolsky, David Caldwell, David
3486 Cantrell, David Golden, David Leadbeater, David Mitchell, David
3487 Wheeler, Eric Brine, Father Chrysostomos, Fingle Nark, Florian Ragwitz,
3488 Frank Wiegand, Franz Fasching, Gene Sullivan, George Greer, Gerard
3489 Goossen, Gisle Aas, Goro Fuji, Grant McLean, gregor herrmann, H.Merijn
3490 Brand, Hongwen Qiu, Hugo van der Sanden, Ian Goodacre, James E Keenan,
3491 James Mastros, Jan Dubois, Jay Hannah, Jerry D. Hedden, Jesse Vincent,
3492 Jim Cromie, Jirka HruXka, John Peacock, Joshua ben Jore, Joshua
3493 Pritikin, Karl Williamson, Kevin Ryde, kmx, Lars DXXXXXX XXX, Larwan
3494 Berke, Leon Brocard, Leon Timmermans, Lubomir Rintel, Lukas Mai, Maik
3495 Hentsche, Marty Pauley, Marvin Humphrey, Matt Johnson, Matt S Trout,
3496 Max Maischein, Michael Breen, Michael Fig, Michael G Schwern, Michael
3497 Parker, Michael Stevens, Michael Witten, Mike Kelly, Moritz Lenz,
3498 Nicholas Clark, Nick Cleaton, Nick Johnston, Nicolas Kaiser, Niko Tyni,
3499 Noirin Shirley, Nuno Carvalho, Paul Evans, Paul Green, Paul Johnson,
3500 Paul Marquess, Peter J. Holzer, Peter John Acklam, Peter Martini,
3501 Philippe Bruhat (BooK), Piotr Fusik, Rafael Garcia-Suarez, Rainer
3502 Tammer, Reini Urban, Renee Baecker, Ricardo Signes, Richard Moehn,
3503 Richard Soderberg, Rob Hoelz, Robin Barker, Ruslan Zakirov, Salvador
3504 Fandin~o, Salvador Ortiz Garcia, Shlomi Fish, Sinan Unur, Sisyphus,
3505 Slaven Rezic, Steffen Mueller, Steve Hay, Steven Schubiger, Steve
3506 Peters, Sullivan Beck, Tatsuhiko Miyagawa, Tim Bunce, Todd Rinaldo, Tom
3507 Christiansen, Tom Hukins, Tony Cook, Tye McQueen, Vadim Konovalov,
3508 Vernon Lyon, Vincent Pit, Walt Mankowski, Wolfram Humann, Yves Orton,
3509 Zefram, and Zsban Ambrus.
3510 This is woefully incomplete as it's automatically generated from
3512 version control history. In particular, it doesn't include the names
3513 of the (very much appreciated) contributors who reported issues in
3514 previous versions of Perl that helped make Perl 5.14.0 better. For a
3515 more complete list of all of Perl's historical contributors, please see
3516 the "AUTHORS" file in the Perl 5.14.0 distribution.
3517 Many of the changes included in this version originated in the CPAN
3519 modules included in Perl's core. We're grateful to the entire CPAN
3520 community for helping Perl to flourish.
3521
3523 If you find what you think is a bug, you might check the articles
3524 recently posted to the comp.lang.perl.misc newsgroup and the Perl bug
3525 database at http://rt.perl.org/perlbug/ . There may also be
3526 information at http://www.perl.org/ , the Perl Home Page.
3527 If you believe you have an unreported bug, please run the perlbug
3529 program included with your release. Be sure to trim your bug down to a
3530 tiny but sufficient test case. Your bug report, along with the output
3531 of "perl -V", will be sent off to perlbug@perl.org to be analysed by
3532 the Perl porting team.
3533 If the bug you are reporting has security implications, which make it
3535 inappropriate to send to a publicly archived mailing list, then please
3536 send it to perl5-security-report@perl.org. This points to a closed
3537 subscription unarchived mailing list, which includes all the core
3538 committers, who are able to help assess the impact of issues, figure
3539 out a resolution, and help co-ordinate the release of patches to
3540 mitigate or fix the problem across all platforms on which Perl is
3541 supported. Please use this address for security issues in the Perl
3542 core only, not for modules independently distributed on CPAN.
3543
3545 The Changes file for an explanation of how to view exhaustive details
3546 on what changed.
3547 The INSTALL file for how to build Perl.
3549 The README file for general stuff.
3551 The Artistic and Copying files for copyright information.
3553perl v5.16.3 2013-03-04 PERL5140DELTA(1)