5 perl5160delta - what is new for perl v5.16.0
9 This document describes differences between the 5.14.0 release and
12 If you are upgrading from an earlier release such as 5.12.0, first read
13 L<perl5140delta>, which describes differences between 5.12.0 and
16 Some bug fixes in this release have been backported to later
17 releases of 5.14.x. Those are indicated with the 5.14.x version in
22 With the release of Perl 5.16.0, the 5.12.x series of releases is now out of
23 its support period. There may be future 5.12.x releases, but only in the
24 event of a critical security issue. Users of Perl 5.12 or earlier should
25 consider upgrading to a more recent release of Perl.
27 This policy is described in greater detail in
28 L<perlpolicy|perlpolicy/MAINTENANCE AND SUPPORT>.
30 =head1 Core Enhancements
32 =head2 C<use I<VERSION>>
34 As of this release, version declarations like C<use v5.16> now disable
35 all features before enabling the new feature bundle. This means that
36 the following holds true:
39 # only 5.16 features enabled here
41 # only 5.14 features enabled here (not 5.16)
43 C<use v5.12> and higher continue to enable strict, but explicit C<use
44 strict> and C<no strict> now override the version declaration, even
51 There is a new ":default" feature bundle that represents the set of
52 features enabled before any version declaration or C<use feature> has
53 been seen. Version declarations below 5.10 now enable the ":default"
54 feature set. This does not actually change the behavior of C<use
55 v5.8>, because features added to the ":default" set are those that were
56 traditionally enabled by default, before they could be turned off.
58 C<< no feature >> now resets to the default feature set. To disable all
59 features (which is likely to be a pretty special-purpose request, since
60 it presumably won't match any named set of semantics) you can now
61 write C<< no feature ':all' >>.
63 C<$[> is now disabled under C<use v5.16>. It is part of the default
64 feature set and can be turned on or off explicitly with C<use feature
69 The new C<__SUB__> token, available under the C<current_sub> feature
70 (see L<feature>) or C<use v5.16>, returns a reference to the current
71 subroutine, making it easier to write recursive closures.
73 =head2 New and Improved Built-ins
75 =head3 More consistent C<eval>
77 The C<eval> operator sometimes treats a string argument as a sequence of
78 characters and sometimes as a sequence of bytes, depending on the
79 internal encoding. The internal encoding is not supposed to make any
80 difference, but there is code that relies on this inconsistency.
82 The new C<unicode_eval> and C<evalbytes> features (enabled under C<use
83 5.16.0>) resolve this. The C<unicode_eval> feature causes C<eval
84 $string> to treat the string always as Unicode. The C<evalbytes>
85 features provides a function, itself called C<evalbytes>, which
86 evaluates its argument always as a string of bytes.
88 These features also fix oddities with source filters leaking to outer
91 See L<feature> for more detail.
93 =head3 C<substr> lvalue revamp
95 =for comment Does this belong here, or under Incompatible Changes?
97 When C<substr> is called in lvalue or potential lvalue context with two
98 or three arguments, a special lvalue scalar is returned that modifies
99 the original string (the first argument) when assigned to.
101 Previously, the offsets (the second and third arguments) passed to
102 C<substr> would be converted immediately to match the string, negative
103 offsets being translated to positive and offsets beyond the end of the
104 string being truncated.
106 Now, the offsets are recorded without modification in the special
107 lvalue scalar that is returned, and the original string is not even
108 looked at by C<substr> itself, but only when the returned lvalue is
111 These changes result in an incompatible change:
113 If the original string changes length after the call to C<substr> but
114 before assignment to its return value, negative offsets will remember
115 their position from the end of the string, affecting code like this:
117 my $string = "string";
118 my $lvalue = \substr $string, -4, 2;
119 print $$lvalue, "\n"; # prints "ri"
120 $string = "bailing twine";
121 print $$lvalue, "\n"; # prints "wi"; used to print "il"
123 The same thing happens with an omitted third argument. The returned
124 lvalue will always extend to the end of the string, even if the string
127 Since this change also allowed many bugs to be fixed (see
128 L</The C<substr> operator>), and since the behavior
129 of negative offsets has never been specified, the
130 change was deemed acceptable.
132 =head3 Return value of C<tied>
134 The value returned by C<tied> on a tied variable is now the actual
135 scalar that holds the object to which the variable is tied. This
136 lets ties be weakened with C<Scalar::Util::weaken(tied
139 =head2 Unicode Support
141 =head3 Supports (I<almost>) Unicode 6.1
143 Besides the addition of whole new scripts, and new characters in
144 existing scripts, this new version of Unicode, as always, makes some
145 changes to existing characters. One change that may trip up some
146 applications is that the General Category of two characters in the
147 Latin-1 range, PILCROW SIGN and SECTION SIGN, has been changed from
148 Other_Symbol to Other_Punctuation. The same change has been made for
149 a character in each of Tibetan, Ethiopic, and Aegean.
150 The code points U+3248..U+324F (CIRCLED NUMBER TEN ON BLACK SQUARE
151 through CIRCLED NUMBER EIGHTY ON BLACK SQUARE) have had their General
152 Category changed from Other_Symbol to Other_Numeric. The Line Break
153 property has changes for Hebrew and Japanese; and because of
154 other changes in 6.1, the Perl regular expression construct C<\X> now
155 works differently for some characters in Thai and Lao.
157 New aliases (synonyms) have been defined for many property values;
158 these, along with the previously existing ones, are all cross-indexed in
161 The return value of C<charnames::viacode()> is affected by other
164 Code point Old Name New Name
165 U+000A LINE FEED (LF) LINE FEED
166 U+000C FORM FEED (FF) FORM FEED
167 U+000D CARRIAGE RETURN (CR) CARRIAGE RETURN
168 U+0085 NEXT LINE (NEL) NEXT LINE
169 U+008E SINGLE-SHIFT 2 SINGLE-SHIFT-2
170 U+008F SINGLE-SHIFT 3 SINGLE-SHIFT-3
171 U+0091 PRIVATE USE 1 PRIVATE USE-1
172 U+0092 PRIVATE USE 2 PRIVATE USE-2
173 U+2118 SCRIPT CAPITAL P WEIERSTRASS ELLIPTIC FUNCTION
175 Perl will accept any of these names as input, but
176 C<charnames::viacode()> now returns the new name of each pair. The
177 change for U+2118 is considered by Unicode to be a correction, that is
178 the original name was a mistake (but again, it will remain forever valid
179 to use it to refer to U+2118). But most of these changes are the
180 fallout of the mistake Unicode 6.0 made in naming a character used in
181 Japanese cell phones to be "BELL", which conflicts with the longstanding
182 industry use of (and Unicode's recommendation to use) that name
183 to mean the ASCII control character at U+0007. Therefore, that name
184 has been deprecated in Perl since v5.14, and any use of it will raise a
185 warning message (unless turned off). The name "ALERT" is now the
186 preferred name for this code point, with "BEL" an acceptable short
187 form. The name for the new cell phone character, at code point U+1F514,
188 remains undefined in this version of Perl (hence we don't
189 implement quite all of Unicode 6.1), but starting in v5.18, BELL will mean
190 this character, and not U+0007.
192 Unicode has taken steps to make sure that this sort of mistake does not
193 happen again. The Standard now includes all generally accepted
194 names and abbreviations for control characters, whereas previously it
195 didn't (though there were recommended names for most of them, which Perl
196 used). This means that most of those recommended names are now
197 officially in the Standard. Unicode did not recommend names for the
198 four code points listed above between U+008E and U+008F, and in
199 standardizing them Unicode subtly changed the names that Perl had
200 previously given them, by replacing the final blank in each name by a
201 hyphen. Unicode also officially accepts names that Perl had deprecated,
202 such as FILE SEPARATOR. Now the only deprecated name is BELL.
203 Finally, Perl now uses the new official names instead of the old
204 (now considered obsolete) names for the first four code points in the
205 list above (the ones which have the parentheses in them).
207 Now that the names have been placed in the Unicode standard, these kinds
208 of changes should not happen again, though corrections, such as to
209 U+2118, are still possible.
211 Unicode also added some name abbreviations, which Perl now accepts:
213 TAB for CHARACTER TABULATION;
214 NEW LINE, END OF LINE, NL, and EOL for LINE FEED;
215 LOCKING-SHIFT ONE for SHIFT OUT;
216 LOCKING-SHIFT ZERO for SHIFT IN;
217 and ZWNBSP for ZERO WIDTH NO-BREAK SPACE.
219 More details on this version of Unicode are provided in
220 L<http://www.unicode.org/versions/Unicode6.1.0/>.
222 =head3 C<use charnames> is no longer needed for C<\N{I<name>}>
224 When C<\N{I<name>}> is encountered, the C<charnames> module is now
225 automatically loaded when needed as if the C<:full> and C<:short>
226 options had been specified. See L<charnames> for more information.
228 =head3 C<\N{...}> can now have Unicode loose name matching
230 This is described in the C<charnames> item in
231 L</Updated Modules and Pragmata> below.
233 =head3 Unicode Symbol Names
235 Perl now has proper support for Unicode in symbol names. It used to be
236 that C<*{$foo}> would ignore the internal UTF8 flag and use the bytes of
237 the underlying representation to look up the symbol. That meant that
238 C<*{"\x{100}"}> and C<*{"\xc4\x80"}> would return the same thing. All
239 these parts of Perl have been fixed to account for Unicode:
245 Method names (including those passed to C<use overload>)
249 Typeglob names (including names of variables, subroutines, and filehandles)
261 Symbolic dereferencing
265 Second argument to C<bless()> and C<tie()>
269 Return value of C<ref()>
273 Subroutine prototypes
281 Various warnings and error messages that mention variable names or values,
286 In addition, a parsing bug has been fixed that prevented C<*{é}> from
287 implicitly quoting the name, but instead interpreted it as C<*{+é}>, which
288 would cause a strict violation.
290 C<*{"*a::b"}> automatically strips off the * if it is followed by an ASCII
291 letter. That has been extended to all Unicode identifier characters.
293 One-character non-ASCII non-punctuation variables (like C<$é>) are now
294 subject to "Used only once" warnings. They used to be exempt, as they
295 were treated as punctuation variables.
297 Also, single-character Unicode punctuation variables (like C<$‰>) are now
298 supported [perl #69032].
300 =head3 Improved ability to mix locales and Unicode, including UTF-8 locales
302 An optional parameter has been added to C<use locale>
304 use locale ':not_characters';
306 which tells Perl to use all but the C<LC_CTYPE> and C<LC_COLLATE>
307 portions of the current locale. Instead, the character set is assumed
308 to be Unicode. This lets locales and Unicode be seamlessly mixed,
309 including the increasingly frequent UTF-8 locales. When using this
310 hybrid form of locales, the C<:locale> layer to the L<open> pragma can
311 be used to interface with the file system, and there are CPAN modules
312 available for ARGV and environment variable conversions.
314 Full details are in L<perllocale>.
316 =head3 New function C<fc> and corresponding escape sequence C<\F> for Unicode foldcase
318 Unicode foldcase is an extension to lowercase that gives better results
319 when comparing two strings case-insensitively. It has long been used
320 internally in regular expression C</i> matching. Now it is available
321 explicitly through the new C<fc> function call (enabled by
322 S<C<"use feature 'fc'">>, or C<use v5.16>, or explicitly callable via
323 C<CORE::fc>) or through the new C<\F> sequence in double-quotish
326 Full details are in L<perlfunc/fc>.
328 =head3 The Unicode C<Script_Extensions> property is now supported.
330 New in Unicode 6.0, this is an improved C<Script> property. Details
331 are in L<perlunicode/Scripts>.
335 =head3 Improved typemaps for Some Builtin Types
337 Most XS authors will know there is a longstanding bug in the
338 OUTPUT typemap for T_AVREF (C<AV*>), T_HVREF (C<HV*>), T_CVREF (C<CV*>),
339 and T_SVREF (C<SVREF> or C<\$foo>) that requires manually decrementing
340 the reference count of the return value instead of the typemap taking
341 care of this. For backwards-compatibility, this cannot be changed in the
342 default typemaps. But we now provide additional typemaps
343 C<T_AVREF_REFCOUNT_FIXED>, etc. that do not exhibit this bug. Using
344 them in your extension is as simple as having one line in your
347 HV* T_HVREF_REFCOUNT_FIXED
349 =head3 C<is_utf8_char()>
351 The XS-callable function C<is_utf8_char()>, when presented with
352 malformed UTF-8 input, can read up to 12 bytes beyond the end of the
353 string. This cannot be fixed without changing its API, and so its
354 use is now deprecated. Use C<is_utf8_char_buf()> (described just below)
357 =head3 Added C<is_utf8_char_buf()>
359 This function is designed to replace the deprecated L</is_utf8_char()>
360 function. It includes an extra parameter to make sure it doesn't read
361 past the end of the input buffer.
363 =head3 Other C<is_utf8_foo()> functions, as well as C<utf8_to_foo()>, etc.
365 Most other XS-callable functions that take UTF-8 encoded input
366 implicitly assume that the UTF-8 is valid (not malformed) with respect to
367 buffer length. Do not do things such as change a character's case or
368 see if it is alphanumeric without first being sure that it is valid
369 UTF-8. This can be safely done for a whole string by using one of the
370 functions C<is_utf8_string()>, C<is_utf8_string_loc()>, and
371 C<is_utf8_string_loclen()>.
375 Many new functions have been added to the API for manipulating lexical
376 pads. See L<perlapi/Pad Data Structures> for more information.
378 =head2 Changes to Special Variables
380 =head3 C<$$> can be assigned to
382 C<$$> was made read-only in Perl 5.8.0. But only sometimes: C<local $$>
383 would make it writable again. Some CPAN modules were using C<local $$> or
384 XS code to bypass the read-only check, so there is no reason to keep C<$$>
385 read-only. (This change also allowed a bug to be fixed while maintaining
386 backward compatibility.)
388 =head3 C<$^X> converted to an absolute path on FreeBSD, OS X and Solaris
390 C<$^X> is now converted to an absolute path on OS X, FreeBSD (without
391 needing F</proc> mounted) and Solaris 10 and 11. This augments the
392 previous approach of using F</proc> on Linux, FreeBSD, and NetBSD
393 (in all cases, where mounted).
395 This makes relocatable perl installations more useful on these platforms.
396 (See "Relocatable @INC" in F<INSTALL>)
398 =head2 Debugger Changes
400 =head3 Features inside the debugger
402 The current Perl's L<feature> bundle is now enabled for commands entered
403 in the interactive debugger.
405 =head3 New option for the debugger's B<t> command
407 The B<t> command in the debugger, which toggles tracing mode, now
408 accepts a numeric argument that determines how many levels of subroutine
411 =head3 C<enable> and C<disable>
413 The debugger now has C<disable> and C<enable> commands for disabling
414 existing breakpoints and re-enabling them. See L<perldebug>.
416 =head3 Breakpoints with file names
418 The debugger's "b" command for setting breakpoints now lets a line
419 number be prefixed with a file name. See
420 L<perldebug/"b [file]:[line] [condition]">.
422 =head2 The C<CORE> Namespace
424 =head3 The C<CORE::> prefix
426 The C<CORE::> prefix can now be used on keywords enabled by
427 L<feature.pm|feature>, even outside the scope of C<use feature>.
429 =head3 Subroutines in the C<CORE> namespace
431 Many Perl keywords are now available as subroutines in the CORE namespace.
432 This lets them be aliased:
434 BEGIN { *entangle = \&CORE::tie }
435 entangle $variable, $package, @args;
437 And for prototypes to be bypassed:
439 sub mytie(\[%$*@]$@) {
440 my ($ref, $pack, @args) = @_;
445 Some of these cannot be called through references or via C<&foo> syntax,
446 but must be called as barewords.
448 See L<CORE> for details.
452 =head3 Anonymous handles
454 Automatically generated file handles are now named __ANONIO__ when the
455 variable name cannot be determined, rather than $__ANONIO__.
457 =head3 Autoloaded sort Subroutines
459 Custom sort subroutines can now be autoloaded [perl #30661]:
462 @sorted = sort foo @list; # uses AUTOLOAD
464 =head3 C<continue> no longer requires the "switch" feature
466 The C<continue> keyword has two meanings. It can introduce a C<continue>
467 block after a loop, or it can exit the current C<when> block. Up to now,
468 the latter meaning was valid only with the "switch" feature enabled, and
469 was a syntax error otherwise. Since the main purpose of feature.pm is to
470 avoid conflicts with user-defined subroutines, there is no reason for
471 C<continue> to depend on it.
473 =head3 DTrace probes for interpreter phase change
475 The C<phase-change> probes will fire when the interpreter's phase
476 changes, which tracks the C<${^GLOBAL_PHASE}> variable. C<arg0> is
477 the new phase name; C<arg1> is the old one. This is useful
478 for limiting your instrumentation to one or more of: compile time,
479 run time, or destruct time.
481 =head3 C<__FILE__()> Syntax
483 The C<__FILE__>, C<__LINE__> and C<__PACKAGE__> tokens can now be written
484 with an empty pair of parentheses after them. This makes them parse the
485 same way as C<time>, C<fork> and other built-in functions.
487 =head3 The C<\$> prototype accepts any scalar lvalue
489 The C<\$> and C<\[$]> subroutine prototypes now accept any scalar lvalue
490 argument. Previously they accepted only scalars beginning with C<$> and
491 hash and array elements. This change makes them consistent with the way
492 the built-in C<read> and C<recv> functions (among others) parse their
493 arguments. This means that one can override the built-in functions with
494 custom subroutines that parse their arguments the same way.
496 =head3 C<_> in subroutine prototypes
498 The C<_> character in subroutine prototypes is now allowed before C<@> or
503 =head2 Use C<is_utf8_char_buf()> and not C<is_utf8_char()>
505 The latter function is now deprecated because its API is insufficient to
506 guarantee that it doesn't read (up to 12 bytes in the worst case) beyond
507 the end of its input string. See
508 L<is_utf8_char_buf()|/Added is_utf8_char_buf()>.
510 =head2 Malformed UTF-8 input could cause attempts to read beyond the end of the buffer
512 Two new XS-accessible functions, C<utf8_to_uvchr_buf()> and
513 C<utf8_to_uvuni_buf()> are now available to prevent this, and the Perl
514 core has been converted to use them.
515 See L</Internal Changes>.
517 =head2 C<File::Glob::bsd_glob()> memory error with GLOB_ALTDIRFUNC (CVE-2011-2728).
519 Calling C<File::Glob::bsd_glob> with the unsupported flag
520 GLOB_ALTDIRFUNC would cause an access violation / segfault. A Perl
521 program that accepts a flags value from an external source could expose
522 itself to denial of service or arbitrary code execution attacks. There
523 are no known exploits in the wild. The problem has been corrected by
524 explicitly disabling all unsupported flags and setting unused function
525 pointers to null. Bug reported by Clément Lecigne. (5.14.2)
527 =head2 Privileges are now set correctly when assigning to C<$(>
529 A hypothetical bug (probably unexploitable in practice) because the
530 incorrect setting of the effective group ID while setting C<$(> has been
531 fixed. The bug would have affected only systems that have C<setresgid()>
532 but not C<setregid()>, but no such systems are known to exist.
536 =head2 Don't read the Unicode data base files in F<lib/unicore>
538 It is now deprecated to directly read the Unicode data base files.
539 These are stored in the F<lib/unicore> directory. Instead, you should
540 use the new functions in L<Unicode::UCD>. These provide a stable API,
541 and give complete information.
543 Perl may at some point in the future change or remove these files. The
544 file which applications were most likely to have used is
545 F<lib/unicore/ToDigit.pl>. L<Unicode::UCD/prop_invmap()> can be used to
546 get at its data instead.
548 =head2 XS functions C<is_utf8_char()>, C<utf8_to_uvchr()> and
551 This function is deprecated because it could read beyond the end of the
552 input string. Use the new L<is_utf8_char_buf()|/Added is_utf8_char_buf()>,
553 C<utf8_to_uvchr_buf()> and C<utf8_to_uvuni_buf()> instead.
555 =head1 Future Deprecations
557 This section serves as a notice of features that are I<likely> to be
558 removed or L<deprecated|perlpolicy/deprecated> in the next release of
559 perl (5.18.0). If your code depends on these features, you should
560 contact the Perl 5 Porters via the L<mailing
561 list|http://lists.perl.org/list/perl5-porters.html> or L<perlbug> to
562 explain your use case and inform the deprecation process.
566 These modules may be marked as deprecated I<from the core>. This only
567 means that they will no longer be installed by default with the core
568 distribution, but will remain available on the CPAN.
606 =head2 Platforms with no supporting programmers
608 These platforms will probably have their
609 special build support removed during the
610 5.17.0 development series.
648 =head2 Other Future Deprecations
654 Swapping of $< and $>
656 For more information about this future deprecation, see L<the relevant RT
657 ticket|https://rt.perl.org/rt3/Ticket/Display.html?id=96212>.
663 Perl supports being built without PerlIO proper, using a stdio or sfio
664 wrapper instead. A perl build like this will not support IO layers and
665 thus Unicode IO, making it rather handicapped.
667 PerlIO supports a C<stdio> layer if stdio use is desired, and similarly a
668 sfio layer could be produced.
672 Unescaped literal C<< "{" >> in regular expressions.
674 Starting with v5.20, it is planned to require a literal C<"{"> to be
675 escaped, for example by preceding it with a backslash. In v5.18, a
676 deprecated warning message will be emitted for all such uses.
677 This affects only patterns that are to match a literal C<"{">. Other
678 uses of this character, such as part of a quantifier or sequence as in
679 those below, are completely unaffected:
685 Removing this will permit extensions to Perl's pattern syntax and better
686 error checking for existing syntax. See L<perlre/Quantifiers> for an
691 Revamping C<< "\Q" >> semantics in double-quotish strings when combined with other escapes.
693 There are several bugs and inconsistencies involving combinations
694 of C<\Q> and escapes like C<\x>, C<\L>, etc., within a C<\Q...\E> pair.
695 These need to be fixed, and doing so will necessarily change current
696 behavior. The changes have not yet been settled.
700 =head1 Incompatible Changes
702 =head2 Special blocks called in void context
704 Special blocks (C<BEGIN>, C<CHECK>, C<INIT>, C<UNITCHECK>, C<END>) are now
705 called in void context. This avoids wasteful copying of the result of the
706 last statement [perl #108794].
708 =head2 The C<overloading> pragma and regexp objects
710 With C<no overloading>, regular expression objects returned by C<qr//> are
711 now stringified as "Regexp=REGEXP(0xbe600d)" instead of the regular
712 expression itself [perl #108780].
714 =head2 Two XS typemap Entries removed
716 Two presumably unused XS typemap entries have been removed from the
717 core typemap: T_DATAUNIT and T_CALLBACK. If you are, against all odds,
718 a user of these, please see the instructions on how to restore them
721 =head2 Unicode 6.1 has incompatibilities with Unicode 6.0
723 These are detailed in L</Supports (almost) Unicode 6.1> above.
724 You can compile this version of Perl to use Unicode 6.0. See
725 L<perlunicode/Hacking Perl to work on earlier Unicode versions (for very serious hackers only)>.
727 =head2 Borland compiler
729 All support for the Borland compiler has been dropped. The code had not
730 worked for a long time anyway.
732 =head2 Certain deprecated Unicode properties are no longer supported by default
734 Perl should never have exposed certain Unicode properties that are used
735 by Unicode internally and not meant to be publicly available. Use of
736 these has generated deprecated warning messages since Perl 5.12. The
737 removed properties are Other_Alphabetic,
738 Other_Default_Ignorable_Code_Point, Other_Grapheme_Extend,
739 Other_ID_Continue, Other_ID_Start, Other_Lowercase, Other_Math, and
742 Perl may be recompiled to include any or all of them; instructions are
744 L<perluniprops/Unicode character properties that are NOT accepted by Perl>.
746 =head2 Dereferencing IO thingies as typeglobs
748 The C<*{...}> operator, when passed a reference to an IO thingy (as in
749 C<*{*STDIN{IO}}>), creates a new typeglob containing just that IO object.
750 Previously, it would stringify as an empty string, but some operators would
751 treat it as undefined, producing an "uninitialized" warning.
752 Now it stringifies as __ANONIO__ [perl #96326].
754 =head2 User-defined case-changing operations
756 This feature was deprecated in Perl 5.14, and has now been removed.
757 The CPAN module L<Unicode::Casing> provides better functionality without
758 the drawbacks that this feature had, as are detailed in the 5.14
760 L<http://perldoc.perl.org/5.14.0/perlunicode.html#User-Defined-Case-Mappings-%28for-serious-hackers-only%29>
762 =head2 XSUBs are now 'static'
764 XSUB C functions are now 'static', that is, they are not visible from
765 outside the compilation unit. Users can use the new C<XS_EXTERNAL(name)>
766 and C<XS_INTERNAL(name)> macros to pick the desired linking behavior.
767 The ordinary C<XS(name)> declaration for XSUBs will continue to declare
768 non-'static' XSUBs for compatibility, but the XS compiler,
769 L<ExtUtils::ParseXS> (C<xsubpp>) will emit 'static' XSUBs by default.
770 L<ExtUtils::ParseXS>'s behavior can be reconfigured from XS using the
771 C<EXPORT_XSUB_SYMBOLS> keyword. See L<perlxs> for details.
773 =head2 Weakening read-only references
775 Weakening read-only references is no longer permitted. It should never
776 have worked anyway, and could sometimes result in crashes.
778 =head2 Tying scalars that hold typeglobs
780 Attempting to tie a scalar after a typeglob was assigned to it would
781 instead tie the handle in the typeglob's IO slot. This meant that it was
782 impossible to tie the scalar itself. Similar problems affected C<tied> and
783 C<untie>: C<tied $scalar> would return false on a tied scalar if the last
784 thing returned was a typeglob, and C<untie $scalar> on such a tied scalar
787 We fixed this problem before Perl 5.14.0, but it caused problems with some
788 CPAN modules, so we put in a deprecation cycle instead.
790 Now the deprecation has been removed and this bug has been fixed. So
791 C<tie $scalar> will always tie the scalar, not the handle it holds. To tie
792 the handle, use C<tie *$scalar> (with an explicit asterisk). The same
793 applies to C<tied *$scalar> and C<untie *$scalar>.
795 =head2 IPC::Open3 no longer provides C<xfork()>, C<xclose_on_exec()>
798 All three functions were private, undocumented, and unexported. They do
799 not appear to be used by any code on CPAN. Two have been inlined and one
802 =head2 C<$$> no longer caches PID
804 Previously, if one called fork(3) from C, Perl's
805 notion of C<$$> could go out of sync with what getpid() returns. By always
806 fetching the value of C<$$> via getpid(), this potential bug is eliminated.
807 Code that depends on the caching behavior will break. As described in
808 L<Core Enhancements|/C<$$> can be assigned to>,
809 C<$$> is now writable, but it will be reset during a
812 =head2 C<$$> and C<getppid()> no longer emulate POSIX semantics under LinuxThreads
814 The POSIX emulation of C<$$> and C<getppid()> under the obsolete
815 LinuxThreads implementation has been removed.
816 This only impacts users of Linux 2.4 and
817 users of Debian GNU/kFreeBSD up to and including 6.0, not the vast
818 majority of Linux installations that use NPTL threads.
820 This means that C<getppid()>, like C<$$>, is now always guaranteed to
821 return the OS's idea of the current state of the process, not perl's
822 cached version of it.
824 See the documentation for L<$$|perlvar/$$> for details.
826 =head2 C<< $< >>, C<< $> >>, C<$(> and C<$)> are no longer cached
828 Similarly to the changes to C<$$> and C<getppid()>, the internal
829 caching of C<< $< >>, C<< $> >>, C<$(> and C<$)> has been removed.
831 When we cached these values our idea of what they were would drift out
832 of sync with reality if someone (e.g., someone embedding perl) called
833 C<sete?[ug]id()> without updating C<PL_e?[ug]id>. Having to deal with
834 this complexity wasn't worth it given how cheap the C<gete?[ug]id()>
837 This change will break a handful of CPAN modules that use the XS-level
838 C<PL_uid>, C<PL_gid>, C<PL_euid> or C<PL_egid> variables.
840 The fix for those breakages is to use C<PerlProc_gete?[ug]id()> to
841 retrieve them (e.g., C<PerlProc_getuid()>), and not to assign to
842 C<PL_e?[ug]id> if you change the UID/GID/EUID/EGID. There is no longer
843 any need to do so since perl will always retrieve the up-to-date
844 version of those values from the OS.
846 =head2 Which Non-ASCII characters get quoted by C<quotemeta> and C<\Q> has changed
848 This is unlikely to result in a real problem, as Perl does not attach
849 special meaning to any non-ASCII character, so it is currently
850 irrelevant which are quoted or not. This change fixes bug [perl #77654] and
851 brings Perl's behavior more into line with Unicode's recommendations.
852 See L<perlfunc/quotemeta>.
854 =head1 Performance Enhancements
860 Improved performance for Unicode properties in regular expressions
862 =for comment Can this be compacted some? -- rjbs, 2012-02-20
864 Matching a code point against a Unicode property is now done via a
865 binary search instead of linear. This means for example that the worst
866 case for a 1000 item property is 10 probes instead of 1000. This
867 inefficiency has been compensated for in the past by permanently storing
868 in a hash the results of a given probe plus the results for the adjacent
869 64 code points, under the theory that near-by code points are likely to
870 be searched for. A separate hash was used for each mention of a Unicode
871 property in each regular expression. Thus, C<qr/\p{foo}abc\p{foo}/>
872 would generate two hashes. Any probes in one instance would be unknown
873 to the other, and the hashes could expand separately to be quite large
874 if the regular expression were used on many different widely-separated
876 Now, however, there is just one hash shared by all instances of a given
877 property. This means that if C<\p{foo}> is matched against "A" in one
878 regular expression in a thread, the result will be known immediately to
879 all regular expressions, and the relentless march of using up memory is
884 Version declarations with the C<use> keyword (e.g., C<use 5.012>) are now
885 faster, as they enable features without loading F<feature.pm>.
889 C<local $_> is faster now, as it no longer iterates through magic that it
890 is not going to copy anyway.
894 Perl 5.12.0 sped up the destruction of objects whose classes define
895 empty C<DESTROY> methods (to prevent autoloading), by simply not
896 calling such empty methods. This release takes this optimization a
897 step further, by not calling any C<DESTROY> method that begins with a
898 C<return> statement. This can be useful for destructors that are only
901 use constant DEBUG => 1;
902 sub DESTROY { return unless DEBUG; ... }
904 Constant-folding will reduce the first statement to C<return;> if DEBUG
905 is set to 0, triggering this optimization.
909 Assigning to a variable that holds a typeglob or copy-on-write scalar
910 is now much faster. Previously the typeglob would be stringified or
911 the copy-on-write scalar would be copied before being clobbered.
915 Assignment to C<substr> in void context is now more than twice its
916 previous speed. Instead of creating and returning a special lvalue
917 scalar that is then assigned to, C<substr> modifies the original string
922 C<substr> no longer calculates a value to return when called in void
927 Due to changes in L<File::Glob>, Perl's C<glob> function and its C<<
928 <...> >> equivalent are now much faster. The splitting of the pattern
929 into words has been rewritten in C, resulting in speed-ups of 20% for
932 This does not affect C<glob> on VMS, as it does not use File::Glob.
936 The short-circuiting operators C<&&>, C<||>, and C<//>, when chained
937 (such as C<$a || $b || $c>), are now considerably faster to short-circuit,
938 due to reduced optree traversal.
942 The implementation of C<s///r> makes one fewer copy of the scalar's value.
946 Recursive calls to lvalue subroutines in lvalue scalar context use less
951 =head1 Modules and Pragmata
953 =head2 Deprecated Modules
957 =item L<Version::Requirements>
959 Version::Requirements is now DEPRECATED, use L<CPAN::Meta::Requirements>,
960 which is a drop-in replacement. It will be deleted from perl.git blead
965 =head2 New Modules and Pragmata
971 L<arybase> -- this new module implements the C<$[> variable.
975 L<PerlIO::mmap> 0.010 has been added to the Perl core.
977 The C<mmap> PerlIO layer is no longer implemented by perl itself, but has
978 been moved out into the new L<PerlIO::mmap> module.
982 =head2 Updated Modules and Pragmata
984 This is only an overview of selected module updates. For a complete list of
987 $ corelist --diff 5.14.0 5.16.0
989 You can substitute your favorite version in place of 5.14.0, too.
995 L<Archive::Extract> has been upgraded from version 0.48 to 0.58.
997 Includes a fix for FreeBSD to only use C<unzip> if it is located in
998 C</usr/local/bin>, as FreeBSD 9.0 will ship with a limited C<unzip> in
1003 L<Archive::Tar> has been upgraded from version 1.76 to 1.82.
1005 Adjustments to handle files >8gb (>0777777777777 octal) and a feature
1006 to return the MD5SUM of files in the archive.
1010 L<base> has been upgraded from version 2.16 to 2.18.
1012 C<base> no longer sets a module's C<$VERSION> to "-1" when a module it
1013 loads does not define a C<$VERSION>. This change has been made because
1014 "-1" is not a valid version number under the new "lax" criteria used
1015 internally by C<UNIVERSAL::VERSION>. (See L<version> for more on "lax"
1018 C<base> no longer internally skips loading modules it has already loaded
1019 and instead relies on C<require> to inspect C<%INC>. This fixes a bug
1020 when C<base> is used with code that clear C<%INC> to force a module to
1025 L<Carp> has been upgraded from version 1.20 to 1.26.
1027 It now includes last read filehandle info and puts a dot after the file
1028 and line number, just like errors from C<die> [perl #106538].
1032 L<charnames> has been updated from version 1.18 to 1.30.
1034 C<charnames> can now be invoked with a new option, C<:loose>,
1035 which is like the existing C<:full> option, but enables Unicode loose
1036 name matching. Details are in L<charnames/LOOSE MATCHES>.
1040 L<B::Deparse> has been upgraded from version 1.03 to 1.14. This fixes
1041 numerous deparsing bugs.
1045 L<CGI> has been upgraded from version 3.52 to 3.59.
1047 It uses the public and documented FCGI.pm API in CGI::Fast. CGI::Fast was
1048 using an FCGI API that was deprecated and removed from documentation
1049 more than ten years ago. Usage of this deprecated API with FCGI E<gt>=
1050 0.70 or FCGI E<lt>= 0.73 introduces a security issue.
1051 L<https://rt.cpan.org/Public/Bug/Display.html?id=68380>
1052 L<http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2011-2766>
1054 Things that may break your code:
1056 C<url()> was fixed to return C<PATH_INFO> when it is explicitly requested
1057 with either the C<path=E<gt>1> or C<path_info=E<gt>1> flag.
1059 If your code is running under mod_rewrite (or compatible) and you are
1060 calling C<self_url()> or you are calling C<url()> and passing
1061 C<path_info=E<gt>1>, these methods will actually be returning
1062 C<PATH_INFO> now, as you have explicitly requested or C<self_url()>
1063 has requested on your behalf.
1065 The C<PATH_INFO> has been omitted in such URLs since the issue was
1066 introduced in the 3.12 release in December, 2005.
1068 This bug is so old your application may have come to depend on it or
1069 workaround it. Check for application before upgrading to this release.
1071 Examples of affected method calls:
1073 $q->url(-absolute => 1, -query => 1, -path_info => 1);
1075 $q->url(-full=>1,-path=>1);
1076 $q->url(-rewrite=>1,-path=>1);
1079 We no longer read from STDIN when the Content-Length is not set,
1080 preventing requests with no Content-Length from sometimes freezing.
1081 This is consistent with the CGI RFC 3875, and is also consistent with
1082 CGI::Simple. However, the old behavior may have been expected by some
1083 command-line uses of CGI.pm.
1085 In addition, the DELETE HTTP verb is now supported.
1089 L<Compress::Zlib> has been upgraded from version 2.035 to 2.048.
1091 IO::Compress::Zip and IO::Uncompress::Unzip now have support for LZMA
1092 (method 14). There is a fix for a CRC issue in IO::Compress::Unzip and
1093 it supports Streamed Stored context now. And fixed a Zip64 issue in
1094 IO::Compress::Zip when the content size was exactly 0xFFFFFFFF.
1098 L<Digest::SHA> has been upgraded from version 5.61 to 5.71.
1100 Added BITS mode to the addfile method and shasum. This makes
1101 partial-byte inputs possible via files/STDIN and lets shasum check
1102 all 8074 NIST Msg vectors, where previously special programming was
1103 required to do this.
1107 L<Encode> has been upgraded from version 2.42 to 2.44.
1109 Missing aliases added, a deep recursion error fixed and various
1110 documentation updates.
1112 Addressed 'decode_xs n-byte heap-overflow' security bug in Unicode.xs
1113 (CVE-2011-2939). (5.14.2)
1117 L<ExtUtils::CBuilder> updated from version 0.280203 to 0.280206.
1119 The new version appends CFLAGS and LDFLAGS to their Config.pm
1124 L<ExtUtils::ParseXS> has been upgraded from version 2.2210 to 3.16.
1126 Much of L<ExtUtils::ParseXS>, the module behind the XS compiler C<xsubpp>,
1127 was rewritten and cleaned up. It has been made somewhat more extensible
1128 and now finally uses strictures.
1130 The typemap logic has been moved into a separate module,
1131 L<ExtUtils::Typemaps>. See L</New Modules and Pragmata>, above.
1133 For a complete set of changes, please see the ExtUtils::ParseXS
1134 changelog, available on the CPAN.
1138 L<File::Glob> has been upgraded from version 1.12 to 1.17.
1140 On Windows, tilde (~) expansion now checks the C<USERPROFILE> environment
1141 variable, after checking C<HOME>.
1143 It has a new C<:bsd_glob> export tag, intended to replace C<:glob>. Like
1144 C<:glob> it overrides C<glob> with a function that does not split the glob
1145 pattern into words, but, unlike C<:glob>, it iterates properly in scalar
1146 context, instead of returning the last file.
1148 There are other changes affecting Perl's own C<glob> operator (which uses
1149 File::Glob internally, except on VMS). See L</Performance Enhancements>
1150 and L</Selected Bug Fixes>.
1154 L<FindBin> updated from version 1.50 to 1.51.
1156 It no longer returns a wrong result if a script of the same name as the
1157 current one exists in the path and is executable.
1161 L<HTTP::Tiny> has been upgraded from version 0.012 to 0.017.
1163 Added support for using C<$ENV{http_proxy}> to set the default proxy host.
1165 Adds additional shorthand methods for all common HTTP verbs,
1166 a C<post_form()> method for POST-ing x-www-form-urlencoded data and
1167 a C<www_form_urlencode()> utility method.
1171 L<IO> has been upgraded from version 1.25_04 to 1.25_06, and L<IO::Handle>
1172 from version 1.31 to 1.33.
1174 Together, these upgrades fix a problem with IO::Handle's C<getline> and
1175 C<getlines> methods. When these methods are called on the special ARGV
1176 handle, the next file is automatically opened, as happens with the built-in
1177 C<E<lt>E<gt>> and C<readline> functions. But, unlike the built-ins, these
1178 methods were not respecting the caller's use of the L<open> pragma and
1179 applying the appropriate I/O layers to the newly-opened file
1180 [rt.cpan.org #66474].
1184 L<IPC::Cmd> has been upgraded from version 0.70 to 0.76.
1186 Capturing of command output (both C<STDOUT> and C<STDERR>) is now supported
1187 using L<IPC::Open3> on MSWin32 without requiring L<IPC::Run>.
1191 L<IPC::Open3> has been upgraded from version 1.09 to 1.12.
1193 Fixes a bug which prevented use of C<open3> on Windows when C<*STDIN>,
1194 C<*STDOUT> or C<*STDERR> had been localized.
1196 Fixes a bug which prevented duplicating numeric file descriptors on Windows.
1198 C<open3> with "-" for the program name works once more. This was broken in
1199 version 1.06 (and hence in Perl 5.14.0) [perl #95748].
1203 L<Locale::Codes> has been upgraded from version 3.16 to 3.21.
1205 Added Language Extension codes (langext) and Language Variation codes (langvar)
1206 as defined in the IANA language registry.
1208 Added language codes from ISO 639-5
1210 Added language/script codes from the IANA language subtag registry
1212 Fixed an uninitialized value warning [rt.cpan.org #67438].
1214 Fixed the return value for the all_XXX_codes and all_XXX_names functions
1215 [rt.cpan.org #69100].
1217 Reorganized modules to move Locale::MODULE to Locale::Codes::MODULE to allow
1218 for cleaner future additions. The original four modules (Locale::Language,
1219 Locale::Currency, Locale::Country, Locale::Script) will continue to work, but
1220 all new sets of codes will be added in the Locale::Codes namespace.
1222 The code2XXX, XXX2code, all_XXX_codes, and all_XXX_names functions now
1223 support retired codes. All codesets may be specified by a constant or
1224 by their name now. Previously, they were specified only by a constant.
1226 The alias_code function exists for backward compatibility. It has been
1227 replaced by rename_country_code. The alias_code function will be
1228 removed some time after September, 2013.
1230 All work is now done in the central module (Locale::Codes). Previously,
1231 some was still done in the wrapper modules (Locale::Codes::*). Added
1232 Language Family codes (langfam) as defined in ISO 639-5.
1236 L<Math::BigFloat> has been upgraded from version 1.993 to 1.997.
1238 The C<numify> method has been corrected to return a normalized Perl number
1239 (the result of C<0 + $thing>), instead of a string [rt.cpan.org #66732].
1243 L<Math::BigInt> has been upgraded from version 1.994 to 1.998.
1245 It provides a new C<bsgn> method that complements the C<babs> method.
1247 It fixes the internal C<objectify> function's handling of "foreign objects"
1248 so they are converted to the appropriate class (Math::BigInt or
1253 L<Math::BigRat> has been upgraded from version 0.2602 to 0.2603.
1255 C<int()> on a Math::BigRat object containing -1/2 now creates a
1256 Math::BigInt containing 0, rather than -0. L<Math::BigInt> does not even
1257 support negative zero, so the resulting object was actually malformed
1262 L<Math::Complex> has been upgraded from version 1.56 to 1.59
1263 and L<Math::Trig> from version 1.2 to 1.22.
1265 Fixes include: correct copy constructor usage; fix polarwise formatting with
1266 numeric format specifier; and more stable C<great_circle_direction> algorithm.
1270 L<Module::CoreList> has been upgraded from version 2.51 to 2.66.
1272 The C<corelist> utility now understands the C<-r> option for displaying
1273 Perl release dates and the C<--diff> option to print the set of modlib
1274 changes between two perl distributions.
1278 L<Module::Metadata> has been upgraded from version 1.000004 to 1.000009.
1280 Adds C<provides> method to generate a CPAN META provides data structure
1281 correctly; use of C<package_versions_from_directory> is discouraged.
1285 L<ODBM_File> has been upgraded from version 1.10 to 1.12.
1287 The XS code is now compiled with C<PERL_NO_GET_CONTEXT>, which will aid
1288 performance under ithreads.
1292 L<open> has been upgraded from version 1.08 to 1.10.
1294 It no longer turns off layers on standard handles when invoked without the
1295 ":std" directive. Similarly, when invoked I<with> the ":std" directive, it
1296 now clears layers on STDERR before applying the new ones, and not just on
1297 STDIN and STDOUT [perl #92728].
1301 L<overload> has been upgraded from version 1.13 to 1.18.
1303 C<overload::Overloaded> no longer calls C<can> on the class, but uses
1304 another means to determine whether the object has overloading. It was
1305 never correct for it to call C<can>, as overloading does not respect
1306 AUTOLOAD. So classes that autoload methods and implement C<can> no longer
1307 have to account for overloading [perl #40333].
1309 A warning is now produced for invalid arguments. See L</New Diagnostics>.
1313 L<PerlIO::scalar> has been upgraded from version 0.11 to 0.14.
1315 (This is the module that implements C<< open $fh, '>', \$scalar >>.)
1317 It fixes a problem with C<< open my $fh, ">", \$scalar >> not working if
1318 C<$scalar> is a copy-on-write scalar. (5.14.2)
1320 It also fixes a hang that occurs with C<readline> or C<< <$fh> >> if a
1321 typeglob has been assigned to $scalar [perl #92258].
1323 It no longer assumes during C<seek> that $scalar is a string internally.
1324 If it didn't crash, it was close to doing so [perl #92706]. Also, the
1325 internal print routine no longer assumes that the position set by C<seek>
1326 is valid, but extends the string to that position, filling the intervening
1327 bytes (between the old length and the seek position) with nulls
1330 Printing to an in-memory handle now works if the $scalar holds a reference,
1331 stringifying the reference before modifying it. References used to be
1332 treated as empty strings.
1334 Printing to an in-memory handle no longer crashes if the $scalar happens to
1335 hold a number internally, but no string buffer.
1337 Printing to an in-memory handle no longer creates scalars that confuse
1338 the regular expression engine [perl #108398].
1342 L<Pod::Functions> has been upgraded from version 1.04 to 1.05.
1344 F<Functions.pm> is now generated at perl build time from annotations in
1345 F<perlfunc.pod>. This will ensure that L<Pod::Functions> and L<perlfunc>
1346 remain in synchronisation.
1350 L<Pod::Html> has been upgraded from version 1.11 to 1.1502.
1352 This is an extensive rewrite of Pod::Html to use L<Pod::Simple> under
1353 the hood. The output has changed significantly.
1357 L<Pod::Perldoc> has been upgraded from version 3.15_03 to 3.17.
1359 It corrects the search paths on VMS [perl #90640]. (5.14.1)
1361 The B<-v> option now fetches the right section for C<$0>.
1363 This upgrade has numerous significant fixes. Consult its changelog on
1364 the CPAN for more information.
1368 L<POSIX> has been upgraded from version 1.24 to 1.30.
1370 L<POSIX> no longer uses L<AutoLoader>. Any code which was relying on this
1371 implementation detail was buggy, and may fail because of this change.
1372 The module's Perl code has been considerably simplified, roughly halving
1373 the number of lines, with no change in functionality. The XS code has
1374 been refactored to reduce the size of the shared object by about 12%,
1375 with no change in functionality. More POSIX functions now have tests.
1377 C<sigsuspend> and C<pause> now run signal handlers before returning, as the
1378 whole point of these two functions is to wait until a signal has
1379 arrived, and then return I<after> it has been triggered. Delayed, or
1380 "safe", signals were preventing that from happening, possibly resulting in
1381 race conditions [perl #107216].
1383 C<POSIX::sleep> is now a direct call into the underlying OS C<sleep>
1384 function, instead of being a Perl wrapper on C<CORE::sleep>.
1385 C<POSIX::dup2> now returns the correct value on Win32 (I<i.e.>, the file
1386 descriptor). C<POSIX::SigSet> C<sigsuspend> and C<sigpending> and
1387 C<POSIX::pause> now dispatch safe signals immediately before returning to
1390 C<POSIX::Termios::setattr> now defaults the third argument to C<TCSANOW>,
1391 instead of 0. On most platforms C<TCSANOW> is defined to be 0, but on some
1392 0 is not a valid parameter, which caused a call with defaults to fail.
1396 L<Socket> has been upgraded from version 1.94 to 2.001.
1398 It has new functions and constants for handling IPv6 sockets:
1403 IPV6_DROP_MEMBERSHIP
1414 L<Storable> has been upgraded from version 2.27 to 2.34.
1416 It no longer turns copy-on-write scalars into read-only scalars when
1417 freezing and thawing.
1421 L<Sys::Syslog> has been upgraded from version 0.27 to 0.29.
1423 This upgrade closes many outstanding bugs.
1427 L<Term::ANSIColor> has been upgraded from version 3.00 to 3.01.
1429 Only interpret an initial array reference as a list of colors, not any initial
1430 reference, allowing the colored function to work properly on objects with
1431 stringification defined.
1435 L<Term::ReadLine> has been upgraded from version 1.07 to 1.09.
1437 Term::ReadLine now supports any event loop, including unpublished ones and
1438 simple L<IO::Select>, loops without the need to rewrite existing code for
1439 any particular framework [perl #108470].
1443 L<threads::shared> has been upgraded from version 1.37 to 1.40.
1445 Destructors on shared objects used to be ignored sometimes if the objects
1446 were referenced only by shared data structures. This has been mostly
1447 fixed, but destructors may still be ignored if the objects still exist at
1448 global destruction time [perl #98204].
1452 L<Unicode::Collate> has been upgraded from version 0.73 to 0.89.
1454 Updated to CLDR 1.9.1
1456 Locales updated to CLDR 2.0: mk, mt, nb, nn, ro, ru, sk, sr, sv, uk,
1457 zh__pinyin, zh__stroke
1459 Newly supported locales: bn, fa, ml, mr, or, pa, sa, si, si__dictionary,
1460 sr_Latn, sv__reformed, ta, te, th, ur, wae.
1462 Tailored compatibility ideographs as well as unified ideographs for the
1463 locales: ja, ko, zh__big5han, zh__gb2312han, zh__pinyin, zh__stroke.
1465 Locale/*.pl files are now searched for in @INC.
1469 L<Unicode::Normalize> has been upgraded from version 1.10 to 1.14.
1471 Fixes for the removal of F<unicore/CompositionExclusions.txt> from core.
1475 L<Unicode::UCD> has been upgraded from version 0.32 to 0.43.
1477 This adds four new functions: C<prop_aliases()> and
1478 C<prop_value_aliases()>, which are used to find all Unicode-approved
1479 synonyms for property names, or to convert from one name to another;
1480 C<prop_invlist> which returns all code points matching a given
1481 Unicode binary property; and C<prop_invmap> which returns the complete
1482 specification of a given Unicode property.
1486 L<Win32API::File> has been upgraded from version 0.1101 to 0.1200.
1488 Added SetStdHandle and GetStdHandle functions
1492 =head2 Removed Modules and Pragmata
1494 As promised in Perl 5.14.0's release notes, the following modules have
1495 been removed from the core distribution, and if needed should be installed
1502 L<Devel::DProf> has been removed from the Perl core. Prior version was
1507 L<Shell> has been removed from the Perl core. Prior version was 0.72_01.
1511 Several old perl4-style libraries which have been deprecated with 5.14
1514 abbrev.pl assert.pl bigfloat.pl bigint.pl bigrat.pl cacheout.pl
1515 complete.pl ctime.pl dotsh.pl exceptions.pl fastcwd.pl flush.pl
1516 getcwd.pl getopt.pl getopts.pl hostname.pl importenv.pl
1517 lib/find{,depth}.pl look.pl newgetopt.pl open2.pl open3.pl
1518 pwd.pl shellwords.pl stat.pl tainted.pl termcap.pl timelocal.pl
1520 They can be found on CPAN as L<Perl4::CoreLibs>.
1524 =head1 Documentation
1526 =head2 New Documentation
1528 =head3 L<perldtrace>
1530 L<perldtrace> describes Perl's DTrace support, listing the provided probes
1531 and gives examples of their use.
1533 =head3 L<perlexperiment>
1535 This document is intended to provide a list of experimental features in
1536 Perl. It is still a work in progress.
1540 This a new OO tutorial. It focuses on basic OO concepts, and then recommends
1541 that readers choose an OO framework from CPAN.
1543 =head3 L<perlxstypemap>
1545 The new manual describes the XS typemapping mechanism in unprecedented
1546 detail and combines new documentation with information extracted from
1547 L<perlxs> and the previously unofficial list of all core typemaps.
1549 =head2 Changes to Existing Documentation
1557 The HV API has long accepted negative lengths to show that the key is
1558 in UTF8. This is now documented.
1562 The C<boolSV()> macro is now documented.
1572 C<dbmopen> treats a 0 mode as a special case, that prevents a nonexistent
1573 file from being created. This has been the case since Perl 5.000, but was
1574 never documented anywhere. Now the perlfunc entry mentions it
1579 As an accident of history, C<open $fh, '<:', ...> applies the default
1580 layers for the platform (C<:raw> on Unix, C<:crlf> on Windows), ignoring
1581 whatever is declared by L<open.pm|open>. This seems such a useful feature
1582 it has been documented in L<perlfunc|perlfunc/open> and L<open>.
1586 The entry for C<split> has been rewritten. It is now far clearer than
1597 A new section, L<Autoloading with XSUBs|perlguts/Autoloading with XSUBs>,
1598 has been added, which explains the two APIs for accessing the name of the
1603 Some function descriptions in L<perlguts> were confusing, as it was
1604 not clear whether they referred to the function above or below the
1605 description. This has been clarified [perl #91790].
1615 This document has been rewritten from scratch, and its coverage of various OO
1616 concepts has been expanded.
1626 Documentation of the smartmatch operator has been reworked and moved from
1627 perlsyn to perlop where it belongs.
1629 It has also been corrected for the case of C<undef> on the left-hand
1630 side. The list of different smart match behaviors had an item in the
1635 Documentation of the ellipsis statement (C<...>) has been reworked and
1636 moved from perlop to perlsyn.
1640 The explanation of bitwise operators has been expanded to explain how they
1641 work on Unicode strings (5.14.1).
1645 More examples for C<m//g> have been added (5.14.1).
1649 The C<<< <<\FOO >>> here-doc syntax has been documented (5.14.1).
1653 =head3 L<perlpragma>
1659 There is now a standard convention for naming keys in the C<%^H>,
1660 documented under L<Key naming|perlpragma/Key naming>.
1664 =head3 L<perlsec/Laundering and Detecting Tainted Data>
1670 The example function for checking for taintedness contained a subtle
1671 error. C<$@> needs to be localized to prevent its changing this
1672 global's value outside the function. The preferred method to check for
1673 this remains L<Scalar::Util/tainted>.
1683 L<perllol> has been expanded with examples using the new C<push $scalar>
1684 syntax introduced in Perl 5.14.0 (5.14.1).
1694 L<perlmod> now states explicitly that some types of explicit symbol table
1695 manipulation are not supported. This codifies what was effectively already
1696 the case [perl #78074].
1700 =head3 L<perlpodstyle>
1706 The tips on which formatting codes to use have been corrected and greatly
1711 There are now a couple of example one-liners for previewing POD files after
1712 they have been edited.
1722 The C<(*COMMIT)> directive is now listed in the right section
1723 (L<Verbs without an argument|perlre/Verbs without an argument>).
1733 L<perlrun> has undergone a significant clean-up. Most notably, the
1734 B<-0x...> form of the B<-0> flag has been clarified, and the final section
1735 on environment variables has been corrected and expanded (5.14.1).
1745 The ($;) prototype syntax, which has existed for rather a long time, is now
1746 documented in L<perlsub>. It lets a unary function have the same
1747 precedence as a list operator.
1757 The required syntax for tying handles has been documented.
1767 The documentation for L<$!|perlvar/$!> has been corrected and clarified.
1768 It used to state that $! could be C<undef>, which is not the case. It was
1769 also unclear whether system calls set C's C<errno> or Perl's C<$!>
1774 Documentation for L<$$|perlvar/$$> has been amended with additional
1775 cautions regarding changing the process ID.
1779 =head3 Other Changes
1785 L<perlxs> was extended with documentation on inline typemaps.
1789 L<perlref> has a new L<Circular References|perlref/Circular References>
1790 section explaining how circularities may not be freed and how to solve that
1791 with weak references.
1795 Parts of L<perlapi> were clarified, and Perl equivalents of some C
1796 functions have been added as an additional mode of exposition.
1800 A few parts of L<perlre> and L<perlrecharclass> were clarified.
1804 =head2 Removed Documentation
1806 =head3 Old OO Documentation
1808 The old OO tutorials, perltoot, perltooc, and perlboot, have been
1809 removed. The perlbot (bag of object tricks) document has been removed
1812 =head3 Development Deltas
1814 The perldelta files for development releases are no longer packaged with
1815 perl. These can still be found in the perl source code repository.
1819 The following additions or changes have been made to diagnostic output,
1820 including warnings and fatal error messages. For the complete list of
1821 diagnostic messages, see L<perldiag>.
1823 =head2 New Diagnostics
1831 L<Cannot set tied @DB::args|perldiag/"Cannot set tied @DB::args">
1833 This error occurs when C<caller> tries to set C<@DB::args> but finds it
1834 tied. Before this error was added, it used to crash instead.
1838 L<Cannot tie unreifiable array|perldiag/"Cannot tie unreifiable array">
1840 This error is part of a safety check that the C<tie> operator does before
1841 tying a special array like C<@_>. You should never see this message.
1845 L<&CORE::%s cannot be called directly|perldiag/"&CORE::%s cannot be called directly">
1847 This occurs when a subroutine in the C<CORE::> namespace is called
1848 with C<&foo> syntax or through a reference. Some subroutines
1849 in this package cannot yet be called that way, but must be
1850 called as barewords. See L</Subroutines in the C<CORE> namespace>, above.
1854 L<Source filters apply only to byte streams|perldiag/"Source filters apply only to byte streams">
1856 This new error occurs when you try to activate a source filter (usually by
1857 loading a source filter module) within a string passed to C<eval> under the
1858 C<unicode_eval> feature.
1868 L<defined(@array) is deprecated|perldiag/"defined(@array) is deprecated">
1870 The long-deprecated C<defined(@array)> now also warns for package variables.
1871 Previously it issued a warning for lexical variables only.
1875 L<length() used on %s|perldiag/length() used on %s>
1877 This new warning occurs when C<length> is used on an array or hash, instead
1878 of C<scalar(@array)> or C<scalar(keys %hash)>.
1882 L<lvalue attribute %s already-defined subroutine|perldiag/"lvalue attribute %s already-defined subroutine">
1884 L<attributes.pm|attributes> now emits this warning when the :lvalue
1885 attribute is applied to a Perl subroutine that has already been defined, as
1886 doing so can have unexpected side-effects.
1890 L<overload arg '%s' is invalid|perldiag/"overload arg '%s' is invalid">
1892 This warning, in the "overload" category, is produced when the overload
1893 pragma is given an argument it doesn't recognize, presumably a mistyped
1898 L<$[ used in %s (did you mean $] ?)|perldiag/"$[ used in %s (did you mean $] ?)">
1900 This new warning exists to catch the mistaken use of C<$[> in version
1901 checks. C<$]>, not C<$[>, contains the version number.
1905 L<Useless assignment to a temporary|perldiag/"Useless assignment to a temporary">
1907 Assigning to a temporary scalar returned
1908 from an lvalue subroutine now produces this
1909 warning [perl #31946].
1913 L<Useless use of \E|perldiag/"Useless use of \E">
1915 C<\E> does nothing unless preceded by C<\Q>, C<\L> or C<\U>.
1919 =head2 Removed Errors
1925 "sort is now a reserved word"
1927 This error used to occur when C<sort> was called without arguments,
1928 followed by C<;> or C<)>. (E.g., C<sort;> would die, but C<{sort}> was
1929 OK.) This error message was added in Perl 3 to catch code like
1930 C<close(sort)> which would no longer work. More than two decades later,
1931 this message is no longer appropriate. Now C<sort> without arguments is
1932 always allowed, and returns an empty list, as it did in those cases
1933 where it was already allowed [perl #90030].
1937 =head2 Changes to Existing Diagnostics
1943 The "Applying pattern match..." or similar warning produced when an
1944 array or hash is on the left-hand side of the C<=~> operator now
1945 mentions the name of the variable.
1949 The "Attempt to free non-existent shared string" has had the spelling
1950 of "non-existent" corrected to "nonexistent". It was already listed
1951 with the correct spelling in L<perldiag>.
1955 The error messages for using C<default> and C<when> outside a
1956 topicalizer have been standardized to match the messages for C<continue>
1957 and loop controls. They now read 'Can't "default" outside a
1958 topicalizer' and 'Can't "when" outside a topicalizer'. They both used
1959 to be 'Can't use when() outside a topicalizer' [perl #91514].
1963 The message, "Code point 0x%X is not Unicode, no properties match it;
1964 all inverse properties do" has been changed to "Code point 0x%X is not
1965 Unicode, all \p{} matches fail; all \P{} matches succeed".
1969 Redefinition warnings for constant subroutines used to be mandatory,
1970 even occurring under C<no warnings>. Now they respect the L<warnings>
1975 The "glob failed" warning message is now suppressible via C<no warnings>
1980 The L<Invalid version format|perldiag/"Invalid version format (%s)">
1981 error message now says "negative version number" within the parentheses,
1982 rather than "non-numeric data", for negative numbers.
1987 L<Possible attempt to put comments in qw() list|perldiag/"Possible attempt to put comments in qw() list">
1989 L<Possible attempt to separate words with commas|perldiag/"Possible attempt to separate words with commas">
1990 are no longer mutually exclusive: the same C<qw> construct may produce
1995 The uninitialized warning for C<y///r> when C<$_> is implicit and
1996 undefined now mentions the variable name, just like the non-/r variation
2001 The 'Use of "foo" without parentheses is ambiguous' warning has been
2002 extended to apply also to user-defined subroutines with a (;$)
2003 prototype, and not just to built-in functions.
2007 Warnings that mention the names of lexical (C<my>) variables with
2008 Unicode characters in them now respect the presence or absence of the
2009 C<:utf8> layer on the output handle, instead of outputting UTF8
2010 regardless. Also, the correct names are included in the strings passed
2011 to C<$SIG{__WARN__}> handlers, rather than the raw UTF8 bytes.
2015 =head1 Utility Changes
2023 L<h2ph> used to generate code of the form
2025 unless(defined(&FOO)) {
2029 But the subroutine is a compile-time declaration, and is hence unaffected
2030 by the condition. It has now been corrected to emit a string C<eval>
2031 around the subroutine [perl #99368].
2041 F<splain> no longer emits backtraces with the first line number repeated.
2045 Uncaught exception from user code:
2046 Cannot fwiddle the fwuddle at -e line 1.
2048 main::baz() called at -e line 1
2049 main::bar() called at -e line 1
2050 main::foo() called at -e line 1
2054 Uncaught exception from user code:
2055 Cannot fwiddle the fwuddle at -e line 1.
2056 main::baz() called at -e line 1
2057 main::bar() called at -e line 1
2058 main::foo() called at -e line 1
2062 Some error messages consist of multiple lines that are listed as separate
2063 entries in L<perldiag>. splain has been taught to find the separate
2064 entries in these cases, instead of simply failing to find the message.
2068 =head3 L<zipdetails>
2074 This is a new utility, included as part of an
2075 L<IO::Compress::Base> upgrade.
2077 L<zipdetails> displays information about the internal record structure
2078 of the zip file. It is not concerned with displaying any details of
2079 the compressed data stored in the zip file.
2083 =head1 Configuration and Compilation
2089 F<regexp.h> has been modified for compatibility with GCC's B<-Werror>
2090 option, as used by some projects that include perl's header files (5.14.1).
2094 C<USE_LOCALE{,_COLLATE,_CTYPE,_NUMERIC}> have been added the output of perl -V
2095 as they have affect the behavior of the interpreter binary (albeit
2096 in only a small area).
2100 The code and tests for L<IPC::Open2> have been moved from F<ext/IPC-Open2>
2101 into F<ext/IPC-Open3>, as C<IPC::Open2::open2()> is implemented as a thin
2102 wrapper around C<IPC::Open3::_open3()>, and hence is very tightly coupled to
2107 The magic types and magic vtables are now generated from data in a new script
2108 F<regen/mg_vtable.pl>, instead of being maintained by hand. As different
2109 EBCDIC variants can't agree on the code point for '~', the character to code
2110 point conversion is done at build time by F<generate_uudmap> to a new generated
2111 header F<mg_data.h>. C<PL_vtbl_bm> and C<PL_vtbl_fm> are now defined by the
2112 pre-processor as C<PL_vtbl_regexp>, instead of being distinct C variables.
2113 C<PL_vtbl_sig> has been removed.
2117 Building with C<-DPERL_GLOBAL_STRUCT> works again. This configuration is not
2122 Perl configured with I<MAD> now correctly frees C<MADPROP> structures when
2123 OPs are freed. C<MADPROP>s are now allocated with C<PerlMemShared_malloc()>
2127 F<makedef.pl> has been refactored. This should have no noticeable affect on
2128 any of the platforms that use it as part of their build (AIX, VMS, Win32).
2132 C<useperlio> can no longer be disabled.
2136 The file F<global.sym> is no longer needed, and has been removed. It
2137 contained a list of all exported functions, one of the files generated by
2138 F<regen/embed.pl> from data in F<embed.fnc> and F<regen/opcodes>. The code
2139 has been refactored so that the only user of F<global.sym>, F<makedef.pl>,
2140 now reads F<embed.fnc> and F<regen/opcodes> directly, removing the need to
2141 store the list of exported functions in an intermediate file.
2143 As F<global.sym> was never installed, this change should not be visible
2144 outside the build process.
2148 F<pod/buildtoc>, used by the build process to build L<perltoc>, has been
2149 refactored and simplified. It now contains only code to build L<perltoc>;
2150 the code to regenerate Makefiles has been moved to F<Porting/pod_rules.pl>.
2151 It's a bug if this change has any material effect on the build process.
2155 F<pod/roffitall> is now built by F<pod/buildtoc>, instead of being
2156 shipped with the distribution. Its list of manpages is now generated
2157 (and therefore current). See also RT #103202 for an unresolved related
2162 The man page for C<XS::Typemap> is no longer installed. C<XS::Typemap>
2163 is a test module which is not installed, hence installing its
2164 documentation makes no sense.
2168 The -Dusesitecustomize and -Duserelocatableinc options now work
2173 =head1 Platform Support
2175 =head2 Platform-Specific Notes
2183 Since version 1.7, Cygwin supports native UTF-8 paths. If Perl is built
2184 under that environment, directory and filenames will be UTF-8 encoded.
2188 Cygwin does not initialize all original Win32 environment variables. See
2189 F<README.cygwin> for a discussion of the newly-added
2190 C<Cygwin::sync_winenv()> function [perl #110190] and for
2201 HP-UX PA-RISC/64 now supports gcc-4.x
2203 A fix to correct the socketsize now makes the test suite pass on HP-UX
2204 PA-RISC for 64bitall builds. (5.14.2)
2214 Remove unnecessary includes, fix miscellaneous compiler warnings and
2215 close some unclosed comments on F<vms/vms.c>.
2219 Remove sockadapt layer from the VMS build.
2223 Explicit support for VMS versions before v7.0 and DEC C versions
2224 before v6.0 has been removed.
2228 Since Perl 5.10.1, the home-grown C<stat> wrapper has been unable to
2229 distinguish between a directory name containing an underscore and an
2230 otherwise-identical filename containing a dot in the same position
2231 (e.g., t/test_pl as a directory and t/test.pl as a file). This problem
2236 The build on VMS now permits names of the resulting symbols in C code for
2237 Perl longer than 31 characters. Symbols like
2238 C<Perl__it_was_the_best_of_times_it_was_the_worst_of_times> can now be
2239 created freely without causing the VMS linker to seize up.
2249 Numerous build and test failures on GNU/Hurd have been resolved with hints
2250 for building DBM modules, detection of the library search path, and enabling
2251 of large file support.
2261 Perl is now built with dynamic linking on OpenVOS, the minimum supported
2262 version of which is now Release 17.1.0.
2268 The CC workshop C++ compiler is now detected and used on systems that ship
2271 =head1 Internal Changes
2277 The compiled representation of formats is now stored via the C<mg_ptr> of
2278 their C<PERL_MAGIC_fm>. Previously it was stored in the string buffer,
2279 beyond C<SvLEN()>, the regular end of the string. C<SvCOMPILED()> and
2280 C<SvCOMPILED_{on,off}()> now exist solely for compatibility for XS code.
2281 The first is always 0, the other two now no-ops. (5.14.1)
2285 Some global variables have been marked C<const>, members in the interpreter
2286 structure have been re-ordered, and the opcodes have been re-ordered. The
2287 op C<OP_AELEMFAST> has been split into C<OP_AELEMFAST> and C<OP_AELEMFAST_LEX>.
2291 When empting a hash of its elements (e.g., via undef(%h), or %h=()), HvARRAY
2292 field is no longer temporarily zeroed. Any destructors called on the freed
2293 elements see the remaining elements. Thus, %h=() becomes more like
2294 C<delete $h{$_} for keys %h>.
2298 Boyer-Moore compiled scalars are now PVMGs, and the Boyer-Moore tables are now
2299 stored via the mg_ptr of their C<PERL_MAGIC_bm>.
2300 Previously they were PVGVs, with the tables stored in
2301 the string buffer, beyond C<SvLEN()>. This eliminates
2302 the last place where the core stores data beyond C<SvLEN()>.
2306 Simplified logic in C<Perl_sv_magic()> introduces a small change of
2307 behavior for error cases involving unknown magic types. Previously, if
2308 C<Perl_sv_magic()> was passed a magic type unknown to it, it would
2314 Croak "Modification of a read-only value attempted" if read only
2318 Return without error if the SV happened to already have this magic
2322 otherwise croak "Don't know how to handle magic of type \\%o"
2326 Now it will always croak "Don't know how to handle magic of type \\%o", even
2327 on read-only values, or SVs which already have the unknown magic type.
2331 The experimental C<fetch_cop_label> function has been renamed to
2336 The C<cop_store_label> function has been added to the API, but is
2341 F<embedvar.h> has been simplified, and one level of macro indirection for
2342 PL_* variables has been removed for the default (non-multiplicity)
2343 configuration. PERLVAR*() macros now directly expand their arguments to
2344 tokens such as C<PL_defgv>, instead of expanding to C<PL_Idefgv>, with
2345 F<embedvar.h> defining a macro to map C<PL_Idefgv> to C<PL_defgv>. XS code
2346 which has unwarranted chumminess with the implementation may need updating.
2350 An API has been added to explicitly choose whether to export XSUB
2351 symbols. More detail can be found in the comments for commit e64345f8.
2355 The C<is_gv_magical_sv> function has been eliminated and merged with
2356 C<gv_fetchpvn_flags>. It used to be called to determine whether a GV
2357 should be autovivified in rvalue context. Now it has been replaced with a
2358 new C<GV_ADDMG> flag (not part of the API).
2362 The returned code point from the function C<utf8n_to_uvuni()>
2363 when the input is malformed UTF-8, malformations are allowed, and
2364 C<utf8> warnings are off is now the Unicode REPLACEMENT CHARACTER
2365 whenever the malformation is such that no well-defined code point can be
2366 computed. Previously the returned value was essentially garbage. The
2367 only malformations that have well-defined values are a zero-length
2368 string (0 is the return), and overlong UTF-8 sequences.
2372 Padlists are now marked C<AvREAL>; i.e., reference-counted. They have
2373 always been reference-counted, but were not marked real, because F<pad.c>
2374 did its own clean-up, instead of using the usual clean-up code in F<sv.c>.
2375 That caused problems in thread cloning, so now the C<AvREAL> flag is on,
2376 but is turned off in F<pad.c> right before the padlist is freed (after
2377 F<pad.c> has done its custom freeing of the pads).
2381 All C files that make up the Perl core have been converted to UTF-8.
2385 These new functions have been added as part of the work on Unicode symbols:
2397 gv_fetchmeth_pv_autoload
2398 gv_fetchmeth_pvn_autoload
2399 gv_fetchmeth_sv_autoload
2400 gv_fetchmethod_pv_flags
2401 gv_fetchmethod_pvn_flags
2402 gv_fetchmethod_sv_flags
2418 The gv_fetchmethod_*_flags functions, like gv_fetchmethod_flags, are
2419 experimental and may change in a future release.
2423 The following functions were added. These are I<not> part of the API:
2435 There is also a C<HEKf> macro corresponding to C<SVf>, for
2436 interpolating HEKs in formatted strings.
2440 C<sv_catpvn_flags> takes a couple of new internal-only flags,
2441 C<SV_CATBYTES> and C<SV_CATUTF8>, which tell it whether the char array to
2442 be concatenated is UTF8. This allows for more efficient concatenation than
2443 creating temporary SVs to pass to C<sv_catsv>.
2447 For XS AUTOLOAD subs, $AUTOLOAD is set once more, as it was in 5.6.0. This
2448 is in addition to setting C<SvPVX(cv)>, for compatibility with 5.8 to 5.14.
2449 See L<perlguts/Autoloading with XSUBs>.
2453 Perl now checks whether the array (the linearized isa) returned by a MRO
2454 plugin begins with the name of the class itself, for which the array was
2455 created, instead of assuming that it does. This prevents the first element
2456 from being skipped during method lookup. It also means that
2457 C<mro::get_linear_isa> may return an array with one more element than the
2458 MRO plugin provided [perl #94306].
2462 C<PL_curstash> is now reference-counted.
2466 There are now feature bundle hints in C<PL_hints> (C<$^H>) that version
2467 declarations use, to avoid having to load F<feature.pm>. One setting of
2468 the hint bits indicates a "custom" feature bundle, which means that the
2469 entries in C<%^H> still apply. F<feature.pm> uses that.
2471 The C<HINT_FEATURE_MASK> macro is defined in F<perl.h> along with other
2472 hints. Other macros for setting and testing features and bundles are in
2473 the new F<feature.h>. C<FEATURE_IS_ENABLED> (which has moved to
2474 F<feature.h>) is no longer used throughout the codebase, but more specific
2475 macros, e.g., C<FEATURE_SAY_IS_ENABLED>, that are defined in F<feature.h>.
2479 F<lib/feature.pm> is now a generated file, created by the new
2480 F<regen/feature.pl> script, which also generates F<feature.h>.
2484 Tied arrays are now always C<AvREAL>. If C<@_> or C<DB::args> is tied, it
2485 is reified first, to make sure this is always the case.
2489 Two new functions C<utf8_to_uvchr_buf()> and C<utf8_to_uvuni_buf()> have
2490 been added. These are the same as C<utf8_to_uvchr> and
2491 C<utf8_to_uvuni> (which are now deprecated), but take an extra parameter
2492 that is used to guard against reading beyond the end of the input
2494 See L<perlapi/utf8_to_uvchr_buf> and L<perlapi/utf8_to_uvuni_buf>.
2498 The regular expression engine now does TRIE case insensitive matches
2499 under Unicode. This may change the output of C<< use re 'debug'; >>,
2500 and will speed up various things.
2504 There is a new C<wrap_op_checker()> function, which provides a thread-safe
2505 alternative to writing to C<PL_check> directly.
2509 =head1 Selected Bug Fixes
2511 =head2 Array and hash
2517 A bug has been fixed that would cause a "Use of freed value in iteration"
2518 error if the next two hash elements that would be iterated over are
2519 deleted [perl #85026]. (5.14.1)
2523 Deleting the current hash iterator (the hash element that would be returned
2524 by the next call to C<each>) in void context used not to free it
2529 Deletion of methods via C<delete $Class::{method}> syntax used to update
2530 method caches if called in void context, but not scalar or list context.
2534 When hash elements are deleted in void context, the internal hash entry is
2535 now freed before the value is freed, to prevent destructors called by that
2536 latter freeing from seeing the hash in an inconsistent state. It was
2537 possible to cause double-frees if the destructor freed the hash itself
2542 A C<keys> optimization in Perl 5.12.0 to make it faster on empty hashes
2543 caused C<each> not to reset the iterator if called after the last element
2548 Freeing deeply nested hashes no longer crashes [perl #44225].
2552 It is possible from XS code to create hashes with elements that have no
2553 values. The hash element and slice operators used to crash
2554 when handling these in lvalue context. They now
2555 produce a "Modification of non-creatable hash value attempted" error
2560 If list assignment to a hash or array triggered destructors that freed the
2561 hash or array itself, a crash would ensue. This is no longer the case
2566 It used to be possible to free the typeglob of a localized array or hash
2567 (e.g., C<local @{"x"}; delete $::{x}>), resulting in a crash on scope exit.
2571 Some core bugs affecting L<Hash::Util> have been fixed: locking a hash
2572 element that is a glob copy no longer causes the next assignment to it to
2573 corrupt the glob (5.14.2), and unlocking a hash element that holds a
2574 copy-on-write scalar no longer causes modifications to that scalar to
2575 modify other scalars that were sharing the same string buffer.
2585 The C<newHVhv> XS function now works on tied hashes, instead of crashing or
2586 returning an empty hash.
2590 The C<SvIsCOW> C macro now returns false for read-only copies of typeglobs,
2591 such as those created by:
2594 Hash::Util::lock_value %hash, 'elem';
2596 It used to return true.
2600 The C<SvPVutf8> C function no longer tries to modify its argument,
2601 resulting in errors [perl #108994].
2605 C<SvPVutf8> now works properly with magical variables.
2609 C<SvPVbyte> now works properly non-PVs.
2613 When presented with malformed UTF-8 input, the XS-callable functions
2614 C<is_utf8_string()>, C<is_utf8_string_loc()>, and
2615 C<is_utf8_string_loclen()> could read beyond the end of the input
2616 string by up to 12 bytes. This no longer happens. [perl #32080].
2617 However, currently, C<is_utf8_char()> still has this defect, see
2618 L</is_utf8_char()> above.
2622 The C-level C<pregcomp> function could become confused about whether the
2623 pattern was in UTF8 if the pattern was an overloaded, tied, or otherwise
2624 magical scalar [perl #101940].
2628 =head2 Compile-time hints
2634 Tying C<%^H> no longer causes perl to crash or ignore the contents of
2635 C<%^H> when entering a compilation scope [perl #106282].
2639 C<eval $string> and C<require> used not to
2640 localize C<%^H> during compilation if it
2641 was empty at the time the C<eval> call itself was compiled. This could
2642 lead to scary side effects, like C<use re "/m"> enabling other flags that
2643 the surrounding code was trying to enable for its caller [perl #68750].
2647 C<eval $string> and C<require> no longer localize hints (C<$^H> and C<%^H>)
2648 at run time, but only during compilation of the $string or required file.
2649 This makes C<BEGIN { $^H{foo}=7 }> equivalent to
2650 C<BEGIN { eval '$^H{foo}=7' }> [perl #70151].
2654 Creating a BEGIN block from XS code (via C<newXS> or C<newATTRSUB>) would,
2655 on completion, make the hints of the current compiling code the current
2656 hints. This could cause warnings to occur in a non-warning scope.
2660 =head2 Copy-on-write scalars
2662 Copy-on-write or shared hash key scalars
2663 were introduced in 5.8.0, but most Perl code
2664 did not encounter them (they were used mostly internally). Perl
2665 5.10.0 extended them, such that assigning C<__PACKAGE__> or a
2666 hash key to a scalar would make it copy-on-write. Several parts
2667 of Perl were not updated to account for them, but have now been fixed.
2673 C<utf8::decode> had a nasty bug that would modify copy-on-write scalars'
2674 string buffers in place (i.e., skipping the copy). This could result in
2675 hashes having two elements with the same key [perl #91834]. (5.14.2)
2679 Lvalue subroutines were not allowing COW scalars to be returned. This was
2680 fixed for lvalue scalar context in Perl 5.12.3 and 5.14.0, but list context
2681 was not fixed until this release.
2685 Elements of restricted hashes (see the L<fields> pragma) containing
2686 copy-on-write values couldn't be deleted, nor could such hashes be cleared
2687 (C<%hash = ()>). (5.14.2)
2691 Localizing a tied variable used to make it read-only if it contained a
2692 copy-on-write string. (5.14.2)
2696 Assigning a copy-on-write string to a stash
2697 element no longer causes a double free. Regardless of this change, the
2698 results of such assignments are still undefined.
2702 Assigning a copy-on-write string to a tied variable no longer stops that
2703 variable from being tied if it happens to be a PVMG or PVLV internally.
2707 Doing a substitution on a tied variable returning a copy-on-write
2708 scalar used to cause an assertion failure or an "Attempt to free
2709 nonexistent shared string" warning.
2713 This one is a regression from 5.12: In 5.14.0, the bitwise assignment
2714 operators C<|=>, C<^=> and C<&=> started leaving the left-hand side
2715 undefined if it happened to be a copy-on-write string [perl #108480].
2719 L<Storable>, L<Devel::Peek> and L<PerlIO::scalar> had similar problems.
2720 See L</Updated Modules and Pragmata>, above.
2730 F<dumpvar.pl>, and therefore the C<x> command in the debugger, have been
2731 fixed to handle objects blessed into classes whose names contain "=". The
2732 contents of such objects used not to be dumped [perl #101814].
2736 The "R" command for restarting a debugger session has been fixed to work on
2737 Windows, or any other system lacking a C<POSIX::_SC_OPEN_MAX> constant
2742 The C<#line 42 foo> directive used not to update the arrays of lines used
2743 by the debugger if it occurred in a string eval. This was partially fixed
2744 in 5.14, but it worked only for a single C<#line 42 foo> in each eval. Now
2745 it works for multiple.
2749 When subroutine calls are intercepted by the debugger, the name of the
2750 subroutine or a reference to it is stored in C<$DB::sub>, for the debugger
2751 to access. Sometimes (such as C<$foo = *bar; undef *bar; &$foo>)
2752 C<$DB::sub> would be set to a name that could not be used to find the
2753 subroutine, and so the debugger's attempt to call it would fail. Now the
2754 check to see whether a reference is needed is more robust, so those
2755 problems should not happen anymore [rt.cpan.org #69862].
2759 Every subroutine has a filename associated with it that the debugger uses.
2760 The one associated with constant subroutines used to be misallocated when
2761 cloned under threads. Consequently, debugging threaded applications could
2762 result in memory corruption [perl #96126].
2766 =head2 Dereferencing operators
2772 C<defined(${"..."})>, C<defined(*{"..."})>, etc., used to
2773 return true for most, but not all built-in variables, if
2774 they had not been used yet. This bug affected C<${^GLOBAL_PHASE}> and
2775 C<${^UTF8CACHE}>, among others. It also used to return false if the
2776 package name was given as well (C<${"::!"}>) [perl #97978, #97492].
2780 Perl 5.10.0 introduced a similar bug: C<defined(*{"foo"})> where "foo"
2781 represents the name of a built-in global variable used to return false if
2782 the variable had never been used before, but only on the I<first> call.
2783 This, too, has been fixed.
2787 Since 5.6.0, C<*{ ... }> has been inconsistent in how it treats undefined
2788 values. It would die in strict mode or lvalue context for most undefined
2789 values, but would be treated as the empty string (with a warning) for the
2790 specific scalar return by C<undef()> (C<&PL_sv_undef> internally). This
2791 has been corrected. C<undef()> is now treated like other undefined
2792 scalars, as in Perl 5.005.
2796 =head2 Filehandle, last-accessed
2798 Perl has an internal variable that stores the last filehandle to be
2799 accessed. It is used by C<$.> and by C<tell> and C<eof> without
2806 It used to be possible to set this internal variable to a glob copy and
2807 then modify that glob copy to be something other than a glob, and still
2808 have the last-accessed filehandle associated with the variable after
2809 assigning a glob to it again:
2811 my $foo = *STDOUT; # $foo is a glob copy
2812 <$foo>; # $foo is now the last-accessed handle
2813 $foo = 3; # no longer a glob
2814 $foo = *STDERR; # still the last-accessed handle
2816 Now the C<$foo = 3> assignment unsets that internal variable, so there
2817 is no last-accessed filehandle, just as if C<< <$foo> >> had never
2820 This also prevents some unrelated handle from becoming the last-accessed
2821 handle if $foo falls out of scope and the same internal SV gets used for
2822 another handle [perl #97988].
2826 A regression in 5.14 caused these statements not to set that internal
2838 This is now fixed, but C<tell *{ *$fh }> still has the problem, and it
2839 is not clear how to fix it [perl #106536].
2843 =head2 Filetests and C<stat>
2845 The term "filetests" refers to the operators that consist of a hyphen
2846 followed by a single letter: C<-r>, C<-x>, C<-M>, etc. The term "stacked"
2847 when applied to filetests means followed by another filetest operator
2848 sharing the same operand, as in C<-r -x -w $fooo>.
2854 C<stat> produces more consistent warnings. It no longer warns for "_"
2855 [perl #71002] and no longer skips the warning at times for other unopened
2856 handles. It no longer warns about an unopened handle when the operating
2857 system's C<fstat> function fails.
2861 C<stat> would sometimes return negative numbers for large inode numbers,
2862 because it was using the wrong internal C type. [perl #84590]
2866 C<lstat> is documented to fall back to C<stat> (with a warning) when given
2867 a filehandle. When passed an IO reference, it was actually doing the
2868 equivalent of S<C<stat _>> and ignoring the handle.
2872 C<-T _> with no preceding C<stat> used to produce a
2873 confusing "uninitialized" warning, even though there
2874 is no visible uninitialized value to speak of.
2878 C<-T>, C<-B>, C<-l> and C<-t> now work
2879 when stacked with other filetest operators
2884 In 5.14.0, filetest ops (C<-r>, C<-x>, etc.) started calling FETCH on a
2885 tied argument belonging to the previous argument to a list operator, if
2886 called with a bareword argument or no argument at all. This has been
2887 fixed, so C<push @foo, $tied, -r> no longer calls FETCH on C<$tied>.
2891 In Perl 5.6, C<-l> followed by anything other than a bareword would treat
2892 its argument as a file name. That was changed in 5.8 for glob references
2893 (C<\*foo>), but not for globs themselves (C<*foo>). C<-l> started
2894 returning C<undef> for glob references without setting the last
2895 stat buffer that the "_" handle uses, but only if warnings
2896 were turned on. With warnings off, it was the same as 5.6.
2897 In other words, it was simply buggy and inconsistent. Now the 5.6
2898 behavior has been restored.
2902 C<-l> followed by a bareword no longer "eats" the previous argument to
2903 the list operator in whose argument list it resides. Hence,
2904 C<print "bar", -l foo> now actually prints "bar", because C<-l>
2909 Perl keeps several internal variables to keep track of the last stat
2910 buffer, from which file(handle) it originated, what type it was, and
2911 whether the last stat succeeded.
2913 There were various cases where these could get out of synch, resulting in
2914 inconsistent or erratic behavior in edge cases (every mention of C<-T>
2915 applies to C<-B> as well):
2921 C<-T I<HANDLE>>, even though it does a C<stat>, was not resetting the last
2922 stat type, so an C<lstat _> following it would merrily return the wrong
2923 results. Also, it was not setting the success status.
2927 Freeing the handle last used by C<stat> or a filetest could result in
2928 S<C<-T _>> using an unrelated handle.
2932 C<stat> with an IO reference would not reset the stat type or record the
2933 filehandle for S<C<-T _>> to use.
2937 Fatal warnings could cause the stat buffer not to be reset
2938 for a filetest operator on an unopened filehandle or C<-l> on any handle.
2939 Fatal warnings also stopped C<-T> from setting C<$!>.
2943 When the last stat was on an unreadable file, C<-T _> is supposed to
2944 return C<undef>, leaving the last stat buffer unchanged. But it was
2945 setting the stat type, causing C<lstat _> to stop working.
2949 C<-T I<FILENAME>> was not resetting the internal stat buffers for
2954 These have all been fixed.
2964 Several edge cases have been fixed with formats and C<formline>;
2965 in particular, where the format itself is potentially variable (such as
2966 with ties and overloading), and where the format and data differ in their
2967 encoding. In both these cases, it used to possible for the output to be
2968 corrupted [perl #91032].
2972 C<formline> no longer converts its argument into a string in-place. So
2973 passing a reference to C<formline> no longer destroys the reference
2978 Assignment to C<$^A> (the format output accumulator) now recalculates
2979 the number of lines output.
2983 =head2 C<given> and C<when>
2989 C<given> was not scoping its implicit $_ properly, resulting in memory
2990 leaks or "Variable is not available" warnings [perl #94682].
2994 C<given> was not calling set-magic on the implicit lexical C<$_> that it
2995 uses. This meant, for example, that C<pos> would be remembered from one
2996 execution of the same C<given> block to the next, even if the input were a
2997 different variable [perl #84526].
3001 C<when> blocks are now capable of returning variables declared inside the
3002 enclosing C<given> block [perl #93548].
3006 =head2 The C<glob> operator
3012 On OSes other than VMS, Perl's C<glob> operator (and the C<< <...> >> form)
3013 use L<File::Glob> underneath. L<File::Glob> splits the pattern into words,
3014 before feeding each word to its C<bsd_glob> function.
3016 There were several inconsistencies in the way the split was done. Now
3017 quotation marks (' and ") are always treated as shell-style word delimiters
3018 (that allow whitespace as part of a word) and backslashes are always
3019 preserved, unless they exist to escape quotation marks. Before, those
3020 would only sometimes be the case, depending on whether the pattern
3021 contained whitespace. Also, escaped whitespace at the end of the pattern
3022 is no longer stripped [perl #40470].
3026 C<CORE::glob> now works as a way to call the default globbing function. It
3027 used to respect overrides, despite the C<CORE::> prefix.
3031 Under miniperl (used to configure modules when perl itself is built),
3032 C<glob> now clears %ENV before calling csh, since the latter croaks on some
3033 systems if it does not like the contents of the LS_COLORS environment
3034 variable [perl #98662].
3038 =head2 Lvalue subroutines
3044 Explicit return now returns the actual argument passed to return, instead
3045 of copying it [perl #72724, #72706].
3049 Lvalue subroutines used to enforce lvalue syntax (i.e., whatever can go on
3050 the left-hand side of C<=>) for the last statement and the arguments to
3051 return. Since lvalue subroutines are not always called in lvalue context,
3052 this restriction has been lifted.
3056 Lvalue subroutines are less restrictive about what values can be returned.
3057 It used to croak on values returned by C<shift> and C<delete> and from
3058 other subroutines, but no longer does so [perl #71172].
3062 Empty lvalue subroutines (C<sub :lvalue {}>) used to return C<@_> in list
3063 context. All subroutines used to do this, but regular subs were fixed in
3064 Perl 5.8.2. Now lvalue subroutines have been likewise fixed.
3068 Autovivification now works on values returned from lvalue subroutines
3069 [perl #7946], as does returning C<keys> in lvalue context.
3073 Lvalue subroutines used to copy their return values in rvalue context. Not
3074 only was this a waste of CPU cycles, but it also caused bugs. A C<($)>
3075 prototype would cause an lvalue sub to copy its return value [perl #51408],
3076 and C<while(lvalue_sub() =~ m/.../g) { ... }> would loop endlessly
3081 When called in potential lvalue context
3082 (e.g., subroutine arguments or a list
3083 passed to C<for>), lvalue subroutines used to copy
3084 any read-only value that was returned. E.g., C< sub :lvalue { $] } >
3085 would not return C<$]>, but a copy of it.
3089 When called in potential lvalue context, an lvalue subroutine returning
3090 arrays or hashes used to bind the arrays or hashes to scalar variables,
3091 resulting in bugs. This was fixed in 5.14.0 if an array were the first
3092 thing returned from the subroutine (but not for C<$scalar, @array> or
3093 hashes being returned). Now a more general fix has been applied
3098 Method calls whose arguments were all surrounded with C<my()> or C<our()>
3099 (as in C<< $object->method(my($a,$b)) >>) used to force lvalue context on
3100 the subroutine. This would prevent lvalue methods from returning certain
3105 Lvalue sub calls that are not determined to be such at compile time
3106 (C<&$name> or &{"name"}) are no longer exempt from strict refs if they
3107 occur in the last statement of an lvalue subroutine [perl #102486].
3111 Sub calls whose subs are not visible at compile time, if
3112 they occurred in the last statement of an lvalue subroutine,
3113 would reject non-lvalue subroutines and die with "Can't modify non-lvalue
3114 subroutine call" [perl #102486].
3116 Non-lvalue sub calls whose subs I<are> visible at compile time exhibited
3117 the opposite bug. If the call occurred in the last statement of an lvalue
3118 subroutine, there would be no error when the lvalue sub was called in
3119 lvalue context. Perl would blindly assign to the temporary value returned
3120 by the non-lvalue subroutine.
3124 C<AUTOLOAD> routines used to take precedence over the actual sub being
3125 called (i.e., when autoloading wasn't needed), for sub calls in lvalue or
3126 potential lvalue context, if the subroutine was not visible at compile
3131 Applying the C<:lvalue> attribute to an XSUB or to an aliased subroutine
3132 stub with C<< sub foo :lvalue; >> syntax stopped working in Perl 5.12.
3133 This has been fixed.
3137 Applying the :lvalue attribute to subroutine that is already defined does
3138 not work properly, as the attribute changes the way the sub is compiled.
3139 Hence, Perl 5.12 began warning when an attempt is made to apply the
3140 attribute to an already defined sub. In such cases, the attribute is
3143 But the change in 5.12 missed the case where custom attributes are also
3144 present: that case still silently and ineffectively applied the attribute.
3145 That omission has now been corrected. C<sub foo :lvalue :Whatever> (when
3146 C<foo> is already defined) now warns about the :lvalue attribute, and does
3151 A bug affecting lvalue context propagation through nested lvalue subroutine
3152 calls has been fixed. Previously, returning a value in nested rvalue
3153 context would be treated as lvalue context by the inner subroutine call,
3154 resulting in some values (such as read-only values) being rejected.
3164 Arithmetic assignment (C<$left += $right>) involving overloaded objects
3165 that rely on the 'nomethod' override no longer segfault when the left
3166 operand is not overloaded.
3170 Errors that occur when methods cannot be found during overloading now
3171 mention the correct package name, as they did in 5.8.x, instead of
3172 erroneously mentioning the "overload" package, as they have since 5.10.0.
3176 Undefining C<%overload::> no longer causes a crash.
3180 =head2 Prototypes of built-in keywords
3186 The C<prototype> function no longer dies for the C<__FILE__>, C<__LINE__>
3187 and C<__PACKAGE__> directives. It now returns an empty-string prototype
3188 for them, because they are syntactically indistinguishable from nullary
3189 functions like C<time>.
3193 C<prototype> now returns C<undef> for all overridable infix operators,
3194 such as C<eq>, which are not callable in any way resembling functions.
3195 It used to return incorrect prototypes for some and die for others
3200 The prototypes of several built-in functions--C<getprotobynumber>, C<lock>,
3201 C<not> and C<select>--have been corrected, or at least are now closer to
3202 reality than before.
3206 =head2 Regular expressions
3208 =for comment Is it possible to merge some of these items?
3214 C</[[:ascii:]]/> and C</[[:blank:]]/> now use locale rules under
3215 C<use locale> when the platform supports that. Previously, they used
3216 the platform's native character set.
3220 C<m/[[:ascii:]]/i> and C</\p{ASCII}/i> now match identically (when not
3221 under a differing locale). This fixes a regression introduced in 5.14
3222 in which the first expression could match characters outside of ASCII,
3223 such as the KELVIN SIGN.
3227 C</.*/g> would sometimes refuse to match at the end of a string that ends
3228 with "\n". This has been fixed [perl #109206].
3232 Starting with 5.12.0, Perl used to get its internal bookkeeping muddled up
3233 after assigning C<${ qr// }> to a hash element and locking it with
3234 L<Hash::Util>. This could result in double frees, crashes, or erratic
3239 The new (in 5.14.0) regular expression modifier C</a> when repeated like
3240 C</aa> forbids the characters outside the ASCII range that match
3241 characters inside that range from matching under C</i>. This did not
3242 work under some circumstances, all involving alternation, such as:
3244 "\N{KELVIN SIGN}" =~ /k|foo/iaa;
3246 succeeded inappropriately. This is now fixed.
3250 5.14.0 introduced some memory leaks in regular expression character
3251 classes such as C<[\w\s]>, which have now been fixed. (5.14.1)
3255 An edge case in regular expression matching could potentially loop.
3256 This happened only under C</i> in bracketed character classes that have
3257 characters with multi-character folds, and the target string to match
3258 against includes the first portion of the fold, followed by another
3259 character that has a multi-character fold that begins with the remaining
3260 portion of the fold, plus some more.
3262 "s\N{U+DF}" =~ /[\x{DF}foo]/i
3264 is one such case. C<\xDF> folds to C<"ss">. (5.14.1)
3268 A few characters in regular expression pattern matches did not
3269 match correctly in some circumstances, all involving C</i>. The
3270 affected characters are:
3271 COMBINING GREEK YPOGEGRAMMENI,
3272 GREEK CAPITAL LETTER IOTA,
3273 GREEK CAPITAL LETTER UPSILON,
3274 GREEK PROSGEGRAMMENI,
3275 GREEK SMALL LETTER IOTA WITH DIALYTIKA AND OXIA,
3276 GREEK SMALL LETTER IOTA WITH DIALYTIKA AND TONOS,
3277 GREEK SMALL LETTER UPSILON WITH DIALYTIKA AND OXIA,
3278 GREEK SMALL LETTER UPSILON WITH DIALYTIKA AND TONOS,
3279 LATIN SMALL LETTER LONG S,
3280 LATIN SMALL LIGATURE LONG S T,
3282 LATIN SMALL LIGATURE ST.
3286 A memory leak regression in regular expression compilation
3287 under threading has been fixed.
3291 A regression introduced in 5.14.0 has
3292 been fixed. This involved an inverted
3293 bracketed character class in a regular expression that consisted solely
3294 of a Unicode property. That property wasn't getting inverted outside the
3299 Three problematic Unicode characters now work better in regex pattern matching under C</i>.
3301 In the past, three Unicode characters:
3302 LATIN SMALL LETTER SHARP S,
3303 GREEK SMALL LETTER IOTA WITH DIALYTIKA AND TONOS,
3305 GREEK SMALL LETTER UPSILON WITH DIALYTIKA AND TONOS,
3306 along with the sequences that they fold to
3307 (including "ss" for LATIN SMALL LETTER SHARP S),
3308 did not properly match under C</i>. 5.14.0 fixed some of these cases,
3309 but introduced others, including a panic when one of the characters or
3310 sequences was used in the C<(?(DEFINE)> regular expression predicate.
3311 The known bugs that were introduced in 5.14 have now been fixed; as well
3312 as some other edge cases that have never worked until now. These all
3313 involve using the characters and sequences outside bracketed character
3314 classes under C</i>. This closes [perl #98546].
3316 There remain known problems when using certain characters with
3317 multi-character folds inside bracketed character classes, including such
3318 constructs as C<qr/[\N{LATIN SMALL LETTER SHARP}a-z]/i>. These
3319 remaining bugs are addressed in [perl #89774].
3323 RT #78266: The regex engine has been leaking memory when accessing
3324 named captures that weren't matched as part of a regex ever since 5.10
3325 when they were introduced; e.g., this would consume over a hundred MB of
3328 for (1..10_000_000) {
3329 if ("foo" =~ /(foo|(?<capture>bar))?/) {
3330 my $capture = $+{capture}
3333 system "ps -o rss $$"'
3337 In 5.14, C</[[:lower:]]/i> and C</[[:upper:]]/i> no longer matched the
3338 opposite case. This has been fixed [perl #101970].
3342 A regular expression match with an overloaded object on the right-hand side
3343 would sometimes stringify the object too many times.
3347 A regression has been fixed that was introduced in 5.14, in C</i>
3348 regular expression matching, in which a match improperly fails if the
3349 pattern is in UTF-8, the target string is not, and a Latin-1 character
3350 precedes a character in the string that should match the pattern.
3355 In case-insensitive regular expression pattern matching, no longer on
3356 UTF-8 encoded strings does the scan for the start of match look only at
3357 the first possible position. This caused matches such as
3358 C<"f\x{FB00}" =~ /ff/i> to fail.
3362 The regexp optimizer no longer crashes on debugging builds when merging
3363 fixed-string nodes with inconvenient contents.
3367 A panic involving the combination of the regular expression modifiers
3368 C</aa> and the C<\b> escape sequence introduced in 5.14.0 has been
3369 fixed [perl #95964]. (5.14.2)
3373 The combination of the regular expression modifiers C</aa> and the C<\b>
3374 and C<\B> escape sequences did not work properly on UTF-8 encoded
3375 strings. All non-ASCII characters under C</aa> should be treated as
3376 non-word characters, but what was happening was that Unicode rules were
3377 used to determine wordness/non-wordness for non-ASCII characters. This
3378 is now fixed [perl #95968].
3382 C<< (?foo: ...) >> no longer loses passed in character set.
3386 The trie optimization used to have problems with alternations containing
3387 an empty C<(?:)>, causing C<< "x" =~ /\A(?>(?:(?:)A|B|C?x))\z/ >> not to
3388 match, whereas it should [perl #111842].
3392 Use of lexical (C<my>) variables in code blocks embedded in regular
3393 expressions will no longer result in memory corruption or crashes.
3395 Nevertheless, these code blocks are still experimental, as there are still
3396 problems with the wrong variables being closed over (in loops for instance)
3397 and with abnormal exiting (e.g., C<die>) causing memory corruption.
3401 The C<\h>, C<\H>, C<\v> and C<\V> regular expression metacharacters used to
3402 cause a panic error message when trying to match at the end of the
3403 string [perl #96354].
3407 The abbreviations for four C1 control characters C<MW> C<PM>, C<RI>, and
3408 C<ST> were previously unrecognized by C<\N{}>, vianame(), and
3413 Mentioning a variable named "&" other than C<$&> (i.e., C<@&> or C<%&>) no
3414 longer stops C<$&> from working. The same applies to variables named "'"
3415 and "`" [perl #24237].
3419 Creating a C<UNIVERSAL::AUTOLOAD> sub no longer stops C<%+>, C<%-> and
3420 C<%!> from working some of the time [perl #105024].
3424 =head2 Smartmatching
3430 C<~~> now correctly handles the precedence of Any~~Object, and is not tricked
3431 by an overloaded object on the left-hand side.
3435 In Perl 5.14.0, C<$tainted ~~ @array> stopped working properly. Sometimes
3436 it would erroneously fail (when C<$tainted> contained a string that occurs
3437 in the array I<after> the first element) or erroneously succeed (when
3438 C<undef> occurred after the first element) [perl #93590].
3442 =head2 The C<sort> operator
3448 C<sort> was not treating C<sub {}> and C<sub {()}> as equivalent when
3449 such a sub was provided as the comparison routine. It used to croak on
3454 C<sort> now works once more with custom sort routines that are XSUBs. It
3455 stopped working in 5.10.0.
3459 C<sort> with a constant for a custom sort routine, although it produces
3460 unsorted results, no longer crashes. It started crashing in 5.10.0.
3464 Warnings emitted by C<sort> when a custom comparison routine returns a
3465 non-numeric value now contain "in sort" and show the line number of the
3466 C<sort> operator, rather than the last line of the comparison routine. The
3467 warnings also now occur only if warnings are enabled in the scope where
3468 C<sort> occurs. Previously the warnings would occur if enabled in the
3469 comparison routine's scope.
3473 C<< sort { $a <=> $b } >>, which is optimized internally, now produces
3474 "uninitialized" warnings for NaNs (not-a-number values), since C<< <=> >>
3475 returns C<undef> for those. This brings it in line with
3476 S<C<< sort { 1; $a <=> $b } >>> and other more complex cases, which are not
3477 optimized [perl #94390].
3481 =head2 The C<substr> operator
3487 Tied (and otherwise magical) variables are no longer exempt from the
3488 "Attempt to use reference as lvalue in substr" warning.
3492 That warning now occurs when the returned lvalue is assigned to, not
3493 when C<substr> itself is called. This makes a difference only if the
3494 return value of C<substr> is referenced and later assigned to.
3498 Passing a substring of a read-only value or a typeglob to a function
3499 (potential lvalue context) no longer causes an immediate "Can't coerce"
3500 or "Modification of a read-only value" error. That error occurs only
3501 if the passed value is assigned to.
3503 The same thing happens with the "substr outside of string" error. If
3504 the lvalue is only read from, not written to, it is now just a warning, as
3505 with rvalue C<substr>.
3509 C<substr> assignments no longer call FETCH twice if the first argument
3510 is a tied variable, just once.
3514 =head2 Support for embedded nulls
3516 Some parts of Perl did not work correctly with nulls (C<chr 0>) embedded in
3517 strings. That meant that, for instance, C<< $m = "a\0b"; foo->$m >> would
3518 call the "a" method, instead of the actual method name contained in $m.
3519 These parts of perl have been fixed to support nulls:
3529 Typeglob names (including filehandle and subroutine names)
3533 Package names, including the return value of C<ref()>
3537 Typeglob elements (C<*foo{"THING\0stuff"}>)
3545 Various warnings and error messages that mention variable names or values,
3550 One side effect of these changes is that blessing into "\0" no longer
3551 causes C<ref()> to return false.
3553 =head2 Threading bugs
3559 Typeglobs returned from threads are no longer cloned if the parent thread
3560 already has a glob with the same name. This means that returned
3561 subroutines will now assign to the right package variables [perl #107366].
3565 Some cases of threads crashing due to memory allocation during cloning have
3566 been fixed [perl #90006].
3570 Thread joining would sometimes emit "Attempt to free unreferenced scalar"
3571 warnings if C<caller> had been used from the C<DB> package before thread
3572 creation [perl #98092].
3576 Locking a subroutine (via C<lock &sub>) is no longer a compile-time error
3577 for regular subs. For lvalue subroutines, it no longer tries to return the
3578 sub as a scalar, resulting in strange side effects like C<ref \$_>
3579 returning "CODE" in some instances.
3581 C<lock &sub> is now a run-time error if L<threads::shared> is loaded (a
3582 no-op otherwise), but that may be rectified in a future version.
3586 =head2 Tied variables
3592 Various cases in which FETCH was being ignored or called too many times
3599 C<PerlIO::get_layers> [perl #97956]
3603 C<$tied =~ y/a/b/>, C<chop $tied> and C<chomp $tied> when $tied holds a
3608 When calling C<local $_> [perl #105912]
3612 Four-argument C<select>
3616 A tied buffer passed to C<sysread>
3624 Three-argument C<open>, the third being a tied file handle
3625 (as in C<< open $fh, ">&", $tied >>)
3629 C<sort> with a reference to a tied glob for the comparison routine.
3633 C<..> and C<...> in list context [perl #53554].
3637 C<${$tied}>, C<@{$tied}>, C<%{$tied}> and C<*{$tied}> where the tied
3638 variable returns a string (C<&{}> was unaffected)
3642 C<defined ${ $tied_variable }>
3646 Various functions that take a filehandle argument in rvalue context
3647 (C<close>, C<readline>, etc.) [perl #97482]
3651 Some cases of dereferencing a complex expression, such as
3652 C<${ (), $tied } = 1>, used to call C<FETCH> multiple times, but now call
3657 C<$tied-E<gt>method> where $tied returns a package name--even resulting in
3658 a failure to call the method, due to memory corruption
3662 Assignments like C<*$tied = \&{"..."}> and C<*glob = $tied>
3666 C<chdir>, C<chmod>, C<chown>, C<utime>, C<truncate>, C<stat>, C<lstat> and
3667 the filetest ops (C<-r>, C<-x>, etc.)
3673 C<caller> sets C<@DB::args> to the subroutine arguments when called from
3674 the DB package. It used to crash when doing so if C<@DB::args> happened to
3675 be tied. Now it croaks instead.
3679 Tying an element of %ENV or C<%^H> and then deleting that element would
3680 result in a call to the tie object's DELETE method, even though tying the
3681 element itself is supposed to be equivalent to tying a scalar (the element
3682 is, of course, a scalar) [perl #67490].
3686 When Perl autovivifies an element of a tied array or hash (which entails
3687 calling STORE with a new reference), it now calls FETCH immediately after
3688 the STORE, instead of assuming that FETCH would have returned the same
3689 reference. This can make it easier to implement tied objects [perl #35865, #43011].
3693 Four-argument C<select> no longer produces its "Non-string passed as
3694 bitmask" warning on tied or tainted variables that are strings.
3698 Localizing a tied scalar that returns a typeglob no longer stops it from
3699 being tied till the end of the scope.
3703 Attempting to C<goto> out of a tied handle method used to cause memory
3704 corruption or crashes. Now it produces an error message instead
3709 A bug has been fixed that occurs when a tied variable is used as a
3710 subroutine reference: if the last thing assigned to or returned from the
3711 variable was a reference or typeglob, the C<\&$tied> could either crash or
3712 return the wrong subroutine. The reference case is a regression introduced
3713 in Perl 5.10.0. For typeglobs, it has probably never worked till now.
3717 =head2 Version objects and vstrings
3723 The bitwise complement operator (and possibly other operators, too) when
3724 passed a vstring would leave vstring magic attached to the return value,
3725 even though the string had changed. This meant that
3726 C<< version->new(~v1.2.3) >> would create a version looking like "v1.2.3"
3727 even though the string passed to C<< version->new >> was actually
3728 "\376\375\374". This also caused L<B::Deparse> to deparse C<~v1.2.3>
3729 incorrectly, without the C<~> [perl #29070].
3733 Assigning a vstring to a magic (e.g., tied, C<$!>) variable and then
3734 assigning something else used to blow away all magic. This meant that
3735 tied variables would come undone, C<$!> would stop getting updated on
3736 failed system calls, C<$|> would stop setting autoflush, and other
3737 mischief would take place. This has been fixed.
3741 C<< version->new("version") >> and C<printf "%vd", "version"> no longer
3742 crash [perl #102586].
3746 Version comparisons, such as those that happen implicitly with C<use
3747 v5.43>, no longer cause locale settings to change [perl #105784].
3751 Version objects no longer cause memory leaks in boolean context
3756 =head2 Warnings, redefinition
3762 Subroutines from the C<autouse> namespace are once more exempt from
3763 redefinition warnings. This used to work in 5.005, but was broken in
3764 5.6 for most subroutines. For subs created via XS that redefine
3765 subroutines from the C<autouse> package, this stopped working in 5.10.
3769 New XSUBs now produce redefinition warnings if they overwrite existing
3770 subs, as they did in 5.8.x. (The C<autouse> logic was reversed in
3771 5.10-14. Only subroutines from the C<autouse> namespace would warn
3776 C<newCONSTSUB> used to use compile-time warning hints, instead of
3777 run-time hints. The following code should never produce a redefinition
3778 warning, but it used to, if C<newCONSTSUB> redefined an existing
3784 some_XS_function_that_calls_new_CONSTSUB();
3789 Redefinition warnings for constant subroutines are on by default (what
3790 are known as severe warnings in L<perldiag>). This occurred only
3791 when it was a glob assignment or declaration of a Perl subroutine that
3792 caused the warning. If the creation of XSUBs triggered the warning, it
3793 was not a default warning. This has been corrected.
3797 The internal check to see whether a redefinition warning should occur
3798 used to emit "uninitialized" warnings in cases like this:
3800 use warnings "uninitialized";
3801 use constant {u => undef, v => undef};
3807 =head2 Warnings, "Uninitialized"
3813 Various functions that take a filehandle argument in rvalue context
3814 (C<close>, C<readline>, etc.) used to warn twice for an undefined handle
3819 C<dbmopen> now only warns once, rather than three times, if the mode
3820 argument is C<undef> [perl #90064].
3824 The C<+=> operator does not usually warn when the left-hand side is
3825 C<undef>, but it was doing so for tied variables. This has been fixed
3830 A bug fix in Perl 5.14 introduced a new bug, causing "uninitialized"
3831 warnings to report the wrong variable if the operator in question had
3832 two operands and one was C<%{...}> or C<@{...}>. This has been fixed
3837 C<..> and C<...> in list context now mention the name of the variable in
3838 "uninitialized" warnings for string (as opposed to numeric) ranges.
3842 =head2 Weak references
3848 Weakening the first argument to an automatically-invoked C<DESTROY> method
3849 could result in erroneous "DESTROY created new reference" errors or
3850 crashes. Now it is an error to weaken a read-only reference.
3854 Weak references to lexical hashes going out of scope were not going stale
3855 (becoming undefined), but continued to point to the hash.
3859 Weak references to lexical variables going out of scope are now broken
3860 before any magical methods (e.g., DESTROY on a tie object) are called.
3861 This prevents such methods from modifying the variable that will be seen
3862 the next time the scope is entered.
3866 Creating a weak reference to an @ISA array or accessing the array index
3867 (C<$#ISA>) could result in confused internal bookkeeping for elements
3868 later added to the @ISA array. For instance, creating a weak
3869 reference to the element itself could push that weak reference on to @ISA;
3870 and elements added after use of C<$#ISA> would be ignored by method lookup
3875 =head2 Other notable fixes
3881 C<quotemeta> now quotes consistently the same non-ASCII characters under
3882 C<use feature 'unicode_strings'>, regardless of whether the string is
3883 encoded in UTF-8 or not, hence fixing the last vestiges (we hope) of the
3884 notorious L<perlunicode/The "Unicode Bug">. [perl #77654].
3886 Which of these code points is quoted has changed, based on Unicode's
3887 recommendations. See L<perlfunc/quotemeta> for details.
3891 C<study> is now a no-op, presumably fixing all outstanding bugs related to
3892 study causing regex matches to behave incorrectly!
3896 When one writes C<open foo || die>, which used to work in Perl 4, a
3897 "Precedence problem" warning is produced. This warning used erroneously to
3898 apply to fully-qualified bareword handle names not followed by C<||>. This
3903 After package aliasing (C<*foo:: = *bar::>), C<select> with 0 or 1 argument
3904 would sometimes return a name that could not be used to refer to the
3905 filehandle, or sometimes it would return C<undef> even when a filehandle
3906 was selected. Now it returns a typeglob reference in such cases.
3910 C<PerlIO::get_layers> no longer ignores some arguments that it thinks are
3911 numeric, while treating others as filehandle names. It is now consistent
3912 for flat scalars (i.e., not references).
3916 Unrecognized switches on C<#!> line
3918 If a switch, such as B<-x>, that cannot occur on the C<#!> line is used
3919 there, perl dies with "Can't emulate...".
3921 It used to produce the same message for switches that perl did not
3922 recognize at all, whether on the command line or the C<#!> line.
3924 Now it produces the "Unrecognized switch" error message [perl #104288].
3928 C<system> now temporarily blocks the SIGCHLD signal handler, to prevent the
3929 signal handler from stealing the exit status [perl #105700].
3933 The %n formatting code for C<printf> and C<sprintf>, which causes the number
3934 of characters to be assigned to the next argument, now actually
3935 assigns the number of characters, instead of the number of bytes.
3937 It also works now with special lvalue functions like C<substr> and with
3938 nonexistent hash and array elements [perl #3471, #103492].
3942 Perl skips copying values returned from a subroutine, for the sake of
3943 speed, if doing so would make no observable difference. Because of faulty
3944 logic, this would happen with the
3945 result of C<delete>, C<shift> or C<splice>, even if the result was
3946 referenced elsewhere. It also did so with tied variables about to be freed
3947 [perl #91844, #95548].
3951 C<utf8::decode> now refuses to modify read-only scalars [perl #91850].
3955 Freeing $_ inside a C<grep> or C<map> block, a code block embedded in a
3956 regular expression, or an @INC filter (a subroutine returned by a
3957 subroutine in @INC) used to result in double frees or crashes
3958 [perl #91880, #92254, #92256].
3962 C<eval> returns C<undef> in scalar context or an empty list in list
3963 context when there is a run-time error. When C<eval> was passed a
3964 string in list context and a syntax error occurred, it used to return a
3965 list containing a single undefined element. Now it returns an empty
3966 list in list context for all errors [perl #80630].
3970 C<goto &func> no longer crashes, but produces an error message, when
3971 the unwinding of the current subroutine's scope fires a destructor that
3972 undefines the subroutine being "goneto" [perl #99850].
3976 Perl now holds an extra reference count on the package that code is
3977 currently compiling in. This means that the following code no longer
3978 crashes [perl #101486]:
3981 BEGIN {*Foo:: = *Bar::}
3986 The C<x> repetition operator no longer crashes on 64-bit builds with large
3987 repeat counts [perl #94560].
3991 Calling C<require> on an implicit C<$_> when C<*CORE::GLOBAL::require> has
3992 been overridden does not segfault anymore, and C<$_> is now passed to the
3993 overriding subroutine [perl #78260].
3997 C<use> and C<require> are no longer affected by the I/O layers active in
3998 the caller's scope (enabled by L<open.pm|open>) [perl #96008].
4002 C<our $::é; $é> (which is invalid) no longer produces the "Compilation
4003 error at lib/utf8_heavy.pl..." error message, which it started emitting in
4004 5.10.0 [perl #99984].
4008 On 64-bit systems, C<read()> now understands large string offsets beyond
4013 Errors that occur when processing subroutine attributes no longer cause the
4014 subroutine's op tree to leak.
4018 Passing the same constant subroutine to both C<index> and C<formline> no
4019 longer causes one or the other to fail [perl #89218]. (5.14.1)
4023 List assignment to lexical variables declared with attributes in the same
4024 statement (C<my ($x,@y) : blimp = (72,94)>) stopped working in Perl 5.8.0.
4025 It has now been fixed.
4029 Perl 5.10.0 introduced some faulty logic that made "U*" in the middle of
4030 a pack template equivalent to "U0" if the input string was empty. This has
4031 been fixed [perl #90160]. (5.14.2)
4035 Destructors on objects were not called during global destruction on objects
4036 that were not referenced by any scalars. This could happen if an array
4037 element were blessed (e.g., C<bless \$a[0]>) or if a closure referenced a
4038 blessed variable (C<bless \my @a; sub foo { @a }>).
4040 Now there is an extra pass during global destruction to fire destructors on
4041 any objects that might be left after the usual passes that check for
4042 objects referenced by scalars [perl #36347].
4046 Fixed a case where it was possible that a freed buffer may have been read
4047 from when parsing a here document [perl #90128]. (5.14.1)
4051 C<each(I<ARRAY>)> is now wrapped in C<defined(...)>, like C<each(I<HASH>)>,
4052 inside a C<while> condition [perl #90888].
4056 A problem with context propagation when a C<do> block is an argument to
4057 C<return> has been fixed. It used to cause C<undef> to be returned in
4058 certain cases of a C<return> inside an C<if> block which itself is followed by
4063 Calling C<index> with a tainted constant no longer causes constants in
4064 subsequently compiled code to become tainted [perl #64804].
4068 Infinite loops like C<1 while 1> used to stop C<strict 'subs'> mode from
4069 working for the rest of the block.
4073 For list assignments like C<($a,$b) = ($b,$a)>, Perl has to make a copy of
4074 the items on the right-hand side before assignment them to the left. For
4075 efficiency's sake, it assigns the values on the right straight to the items
4076 on the left if no one variable is mentioned on both sides, as in C<($a,$b) =
4077 ($c,$d)>. The logic for determining when it can cheat was faulty, in that
4078 C<&&> and C<||> on the right-hand side could fool it. So C<($a,$b) =
4079 $some_true_value && ($b,$a)> would end up assigning the value of C<$b> to
4084 Perl no longer tries to apply lvalue context to the string in
4085 C<("string", $variable) ||= 1> (which used to be an error). Since the
4086 left-hand side of C<||=> is evaluated in scalar context, that's a scalar
4087 comma operator, which gives all but the last item void context. There is
4088 no such thing as void lvalue context, so it was a mistake for Perl to try
4089 to force it [perl #96942].
4093 C<caller> no longer leaks memory when called from the DB package if
4094 C<@DB::args> was assigned to after the first call to C<caller>. L<Carp>
4095 was triggering this bug [perl #97010]. (5.14.2)
4099 C<close> and similar filehandle functions, when called on built-in global
4100 variables (like C<$+>), used to die if the variable happened to hold the
4101 undefined value, instead of producing the usual "Use of uninitialized
4106 When autovivified file handles were introduced in Perl 5.6.0, C<readline>
4107 was inadvertently made to autovivify when called as C<readline($foo)> (but
4108 not as C<E<lt>$fooE<gt>>). It has now been fixed never to autovivify.
4112 Calling an undefined anonymous subroutine (e.g., what $x holds after
4113 C<undef &{$x = sub{}}>) used to cause a "Not a CODE reference" error, which
4114 has been corrected to "Undefined subroutine called" [perl #71154].
4118 Causing C<@DB::args> to be freed between uses of C<caller> no longer
4119 results in a crash [perl #93320].
4123 C<setpgrp($foo)> used to be equivalent to C<($foo, setpgrp)>, because
4124 C<setpgrp> was ignoring its argument if there was just one. Now it is
4125 equivalent to C<setpgrp($foo,0)>.
4129 C<shmread> was not setting the scalar flags correctly when reading from
4130 shared memory, causing the existing cached numeric representation in the
4131 scalar to persist [perl #98480].
4135 C<++> and C<--> now work on copies of globs, instead of dying.
4139 C<splice()> doesn't warn when truncating
4141 You can now limit the size of an array using C<splice(@a,MAX_LEN)> without
4142 worrying about warnings.
4146 C<< $$ >> is no longer tainted. Since this value comes directly from
4147 C<< getpid() >>, it is always safe.
4151 The parser no longer leaks a filehandle if STDIN was closed before parsing
4152 started [perl #37033].
4156 C<< die; >> with a non-reference, non-string, or magical (e.g., tainted)
4157 value in $@ now properly propagates that value [perl #111654].
4161 =head1 Known Problems
4167 On Solaris, we have two kinds of failure.
4169 If F<make> is Sun's F<make>, we get an error about a badly formed macro
4170 assignment in the F<Makefile>. That happens when F<./Configure> tries to
4171 make depends. F<Configure> then exits 0, but further F<make>-ing fails.
4173 If F<make> is F<gmake>, F<Configure> completes, then we get errors related
4174 to F</usr/include/stdbool.h>
4178 On Win32, a number of tests hang unless STDERR is redirected. The cause of
4179 this is still under investigation.
4183 When building as root with a umask that prevents files from being
4184 other-readable, F<t/op/filetest.t> will fail. This is a test bug, not a
4185 bug in perl's behavior.
4189 Configuring with a recent gcc and link-time-optimization, such as
4190 C<Configure -Doptimize='-O2 -flto'> fails
4191 because the optimizer optimizes away some of Configure's tests. A
4192 workaround is to omit the C<-flto> flag when running Configure, but add
4193 it back in while actually building, something like
4195 sh Configure -Doptimize=-O2
4196 make OPTIMIZE='-O2 -flto'
4200 The following CPAN modules have test failures with perl 5.16. Patches have
4201 been submitted for all of these, so hopefully there will be new releases
4208 L<Date::Pcalc> version 6.1
4212 L<Module::CPANTS::Analyse> version 0.85
4214 This fails due to problems in L<Module::Find> 0.10 and L<File::MMagic>
4219 L<PerlIO::Util> version 0.72
4225 =head1 Acknowledgements
4227 Perl 5.16.0 represents approximately 12 months of development since Perl
4228 5.14.0 and contains approximately 590,000 lines of changes across 2,500
4229 files from 139 authors.
4231 Perl continues to flourish into its third decade thanks to a vibrant
4232 community of users and developers. The following people are known to
4233 have contributed the improvements that became Perl 5.16.0:
4235 Aaron Crane, Abhijit Menon-Sen, Abigail, Alan Haggai Alavi, Alberto
4236 Simões, Alexandr Ciornii, Andreas König, Andy Dougherty, Aristotle
4237 Pagaltzis, Bo Johansson, Bo Lindbergh, Breno G. de Oliveira, brian d
4238 foy, Brian Fraser, Brian Greenfield, Carl Hayter, Chas. Owens,
4239 Chia-liang Kao, Chip Salzenberg, Chris 'BinGOs' Williams, Christian
4240 Hansen, Christopher J. Madsen, chromatic, Claes Jacobsson, Claudio
4241 Ramirez, Craig A. Berry, Damian Conway, Daniel Kahn Gillmor, Darin
4242 McBride, Dave Rolsky, David Cantrell, David Golden, David Leadbeater,
4243 David Mitchell, Dee Newcum, Dennis Kaarsemaker, Dominic Hargreaves,
4244 Douglas Christopher Wilson, Eric Brine, Father Chrysostomos, Florian
4245 Ragwitz, Frederic Briere, George Greer, Gerard Goossen, Gisle Aas,
4246 H.Merijn Brand, Hojung Youn, Ian Goodacre, James E Keenan, Jan Dubois,
4247 Jerry D. Hedden, Jesse Luehrs, Jesse Vincent, Jilles Tjoelker, Jim
4248 Cromie, Jim Meyering, Joel Berger, Johan Vromans, Johannes Plunien, John
4249 Hawkinson, John P. Linderman, John Peacock, Joshua ben Jore, Juerd
4250 Waalboer, Karl Williamson, Karthik Rajagopalan, Keith Thompson, Kevin J.
4251 Woolley, Kevin Ryde, Laurent Dami, Leo Lapworth, Leon Brocard, Leon
4252 Timmermans, Louis Strous, Lukas Mai, Marc Green, Marcel Grünauer, Mark
4253 A. Stratman, Mark Dootson, Mark Jason Dominus, Martin Hasch, Matthew
4254 Horsfall, Max Maischein, Michael G Schwern, Michael Witten, Mike
4255 Sheldrake, Moritz Lenz, Nicholas Clark, Niko Tyni, Nuno Carvalho, Pau
4256 Amma, Paul Evans, Paul Green, Paul Johnson, Perlover, Peter John Acklam,
4257 Peter Martini, Peter Scott, Phil Monsen, Pino Toscano, Rafael
4258 Garcia-Suarez, Rainer Tammer, Reini Urban, Ricardo Signes, Robin Barker,
4259 Rodolfo Carvalho, Salvador Fandiño, Sam Kimbrel, Samuel Thibault, Shawn
4260 M Moore, Shigeya Suzuki, Shirakata Kentaro, Shlomi Fish, Sisyphus,
4261 Slaven Rezic, Spiros Denaxas, Steffen Müller, Steffen Schwigon, Stephen
4262 Bennett, Stephen Oberholtzer, Stevan Little, Steve Hay, Steve Peters,
4263 Thomas Sibley, Thorsten Glaser, Timothe Litt, Todd Rinaldo, Tom
4264 Christiansen, Tom Hukins, Tony Cook, Vadim Konovalov, Vincent Pit,
4265 Vladimir Timofeev, Walt Mankowski, Yves Orton, Zefram, Zsbán Ambrus,
4266 Ævar Arnfjörð Bjarmason.
4268 The list above is almost certainly incomplete as it is automatically
4269 generated from version control history. In particular, it does not
4270 include the names of the (very much appreciated) contributors who
4271 reported issues to the Perl bug tracker.
4273 Many of the changes included in this version originated in the CPAN
4274 modules included in Perl's core. We're grateful to the entire CPAN
4275 community for helping Perl to flourish.
4277 For a more complete list of all of Perl's historical contributors,
4278 please see the F<AUTHORS> file in the Perl source distribution.
4280 =head1 Reporting Bugs
4282 If you find what you think is a bug, you might check the articles
4283 recently posted to the comp.lang.perl.misc newsgroup and the perl
4284 bug database at L<http://rt.perl.org/perlbug/>. There may also be
4285 information at L<http://www.perl.org/>, the Perl Home Page.
4287 If you believe you have an unreported bug, please run the L<perlbug>
4288 program included with your release. Be sure to trim your bug down
4289 to a tiny but sufficient test case. Your bug report, along with the
4290 output of C<perl -V>, will be sent off to perlbug@perl.org to be
4291 analysed by the Perl porting team.
4293 If the bug you are reporting has security implications, which make it
4294 inappropriate to send to a publicly archived mailing list, then please
4295 send it to perl5-security-report@perl.org. This points to a closed
4296 subscription unarchived mailing list, which includes all core
4297 committers, who will be able to help assess the impact of issues, figure
4298 out a resolution, and help co-ordinate the release of patches to
4299 mitigate or fix the problem across all platforms on which Perl is
4300 supported. Please use this address only for security issues in the Perl
4301 core, not for modules independently distributed on CPAN.
4305 The F<Changes> file for an explanation of how to view exhaustive details
4308 The F<INSTALL> file for how to build Perl.
4310 The F<README> file for general stuff.
4312 The F<Artistic> and F<Copying> files for copyright information.