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perldelta: Move the is_utf8 fix into the fetch/store section
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1=encoding utf8
2
3=head1 NAME
4
5076a392 5perldelta - what is new for perl v5.14.0
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7=head1 DESCRIPTION
8
9This document describes differences between the 5.12.0 release and
10the 5.14.0 release.
11
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12If you are upgrading from an earlier release such as 5.10.0, first read
13L<perl5120delta>, which describes differences between 5.10.0 and
145.12.0.
15
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16Some of the bug fixes in this release have been backported to subsequent
17releases of 5.12.x. Those are indicated with the 5.12.x version in
18parentheses.
19
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20=head1 Notice
21
22XXX Any important notices here
23
24=head1 Core Enhancements
25
1f539a1a 26=head2 Unicode
5076a392 27
1f539a1a 28=head3 Unicode Version 6.0 is now supported (mostly)
5076a392 29
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30Perl comes with the Unicode 6.0 data base updated with
31L<Corrigendum #8|http://www.unicode.org/versions/corrigendum8.html>,
32with one exception noted below.
33See L<http://unicode.org/versions/Unicode6.0.0> for details on the new
34release. Perl does not support any Unicode provisional properties,
a3c24add 35including the new ones for this release.
5076a392 36
1f539a1a 37Unicode 6.0 has chosen to use the name C<BELL> for the character at U+1F514,
e1b1739f 38which is a symbol that looks like a bell, and is used in Japanese cell
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39phones. This conflicts with the long-standing Perl usage of having
40C<BELL> mean the ASCII C<BEL> character, U+0007. In Perl 5.14,
41C<\N{BELL}> will continue to mean U+0007, but its use will generate a
42deprecated warning message, unless such warnings are turned off. The
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43new name for U+0007 in Perl is C<ALERT>, which corresponds nicely
44with the existing shorthand sequence for it, C<"\a">. C<\N{BEL}>
45means U+0007, with no warning given. The character at U+1F514 will not
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46have a name in 5.14, but can be referred to by C<\N{U+1F514}>. The plan
47is that in Perl 5.16, C<\N{BELL}> will refer to U+1F514, and so all code
48that uses C<\N{BELL}> should convert by then to using C<\N{ALERT}>,
49C<\N{BEL}>, or C<"\a"> instead.
5076a392 50
1f539a1a 51=head3 Full functionality for C<use feature 'unicode_strings'>
5076a392 52
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53This release provides full functionality for C<use feature
54'unicode_strings'>. Under its scope, all string operations executed and
55regular expressions compiled (even if executed outside its scope) have
56Unicode semantics. See L<feature>.
5076a392 57
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58This feature avoids most forms of the "Unicode Bug" (See
59L<perlunicode/The "Unicode Bug"> for details.) If there is a
60possibility that your code will process Unicode strings, you are
61B<strongly> encouraged to use this subpragma to avoid nasty surprises.
5076a392 62
1f539a1a 63=head3 C<\N{I<name>}> and C<charnames> enhancements
5076a392 64
1f539a1a 65=over
5076a392 66
1f539a1a 67=item *
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68
69C<\N{}> and C<charnames::vianame> now know about the abbreviated
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70character names listed by Unicode, such as NBSP, SHY, LRO, ZWJ, etc., all
71the customary abbreviations for the C0 and C1 control characters (such as
72ACK, BEL, CAN, etc.), and a few new variants of some C1 full names that
73are in common usage.
5076a392 74
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75=item *
76
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77Unicode has a number of named character sequences, in which particular sequences
78of code points are given names. C<\N{...}> now recognizes these.
79
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80=item *
81
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82C<\N{}>, C<charnames::vianame>, C<charnames::viacode> now know about every
83character in Unicode. Previously, they didn't know about the Hangul syllables
84nor a number of CJK (Chinese/Japanese/Korean) characters.
85
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86=item *
87
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88In the past, it was ineffective to override one of Perl's abbreviations
89with your own custom alias. Now it works.
90
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91=item *
92
e1b1739f 93You can also create a custom alias of the ordinal of a
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94character, known by C<\N{...}>, C<charnames::vianame()>, and
95C<charnames::viacode()>. Previously, an alias had to be to an official
96Unicode character name. This made it impossible to create an alias for
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97a code point that had no name, such as those reserved for private
98use.
5076a392 99
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100=item *
101
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102A new function, C<charnames::string_vianame()>, has been added.
103This function is a run-time version of C<\N{...}>, returning the string
104of characters whose Unicode name is its parameter. It can handle
105Unicode named character sequences, whereas the pre-existing
106C<charnames::vianame()> cannot, as the latter returns a single code
107point.
108
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109=back
110
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111See L<charnames> for details on all these changes.
112
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113=head3 New warnings categories for problematic (non-)Unicode code points.
114
115Three new warnings subcategories of "utf8" have been added. These
116allow you to turn off some "utf8" warnings, while allowing
117others warnings to remain on. The three categories are:
118C<surrogate> when UTF-16 surrogates are encountered;
119C<nonchar> when Unicode non-character code points are encountered;
120and C<non_unicode> when code points that are above the legal Unicode
121maximum of 0x10FFFF are encountered.
122
1f539a1a 123=head3 Any unsigned value can be encoded as a character
5076a392 124
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125With this release, Perl is adopting a model that any unsigned value can
126be treated as a code point and encoded internally (as utf8) without
54c7bb16 127warnings - not just the code points that are legal in Unicode.
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128However, unless utf8 or the corresponding sub-category (see previous
129item) warnings have been
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130explicitly lexically turned off, outputting or performing a
131Unicode-defined operation (such as upper-casing) on such a code point
132will generate a warning. Attempting to input these using strict rules
133(such as with the C<:encoding('UTF-8')> layer) will continue to fail.
134Prior to this release the handling was very inconsistent, and incorrect
135in places. Also, the Unicode non-characters, some of which previously were
136erroneously considered illegal in places by Perl, contrary to the Unicode
137standard, are now always legal internally. But inputting or outputting
138them will work the same as for the non-legal Unicode code points, as the
139Unicode standard says they are illegal for "open interchange".
5076a392 140
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141=head3 Unicode database files not installed
142
143The Unicode database files are no longer installed with Perl. This
144doesn't affect any functionality in Perl and saves significant disk
145space. If you previously were explicitly opening and reading those
146files, you can download them from
147L<http://www.unicode.org/Public/zipped/6.0.0/>.
148
1f539a1a 149=head2 Regular Expressions
5076a392 150
1f539a1a 151=head3 C<(?^...)> construct to signify default modifiers
5076a392 152
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153An ASCII caret (also called a "circumflex accent") C<"^">
154immediately following a C<"(?"> in a regular expression
155now means that the subexpression does not inherit the
156surrounding modifiers such as C</i>, but reverts to the
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157Perl defaults. Any modifiers following the caret override the defaults.
158
159The stringification of regular expressions now uses this
160notation. E.g., before, C<qr/hlagh/i> would be stringified as
161C<(?i-xsm:hlagh)>, but now it's stringified as C<(?^i:hlagh)>.
162
163The main purpose of this is to allow tests that rely on the
e1b1739f 164stringification not to have to change when new modifiers are added.
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165See L<perlre/Extended Patterns>.
166
1f539a1a 167=head3 C</d>, C</l>, C</u>, C</a>, and C</aa> modifiers
5076a392 168
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169Four new regular expression modifiers have been added. These are mutually
170exclusive; one only can be turned on at a time.
5076a392 171
959ad7d5 172The C</l> modifier says to compile the regular expression as if it were
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173in the scope of C<use locale>, even if it is not.
174
959ad7d5 175The C</u> modifier says to compile the regular expression as if it were
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176in the scope of a C<use feature "unicode_strings"> pragma.
177
e1b1739f 178The C</d> (default) modifier is used to override any C<use locale> and
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179C<use feature "unicode_strings"> pragmas that are in effect at the time
180of compiling the regular expression.
181
959ad7d5 182The C</a> regular expression modifier restricts C<\s>, C<\d> and C<\w> and
7baaf023 183the Posix (C<[[:posix:]]>) character classes to the ASCII range. Their
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184complements and C<\b> and C<\B> are correspondingly
185affected. Otherwise, C</a> behaves like the C</u> modifier, in that
e1b1739f 186case-insensitive matching uses Unicode semantics.
5076a392 187
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188The C</aa> modifier is like C</a>, except that, in case-insensitive matching, no ASCII character will match a
189non-ASCII character. For example,
5076a392 190
959ad7d5 191 'k' =~ /\N{KELVIN SIGN}/ai
5076a392 192
959ad7d5 193will match; it won't under C</aa>.
5076a392 194
959ad7d5 195See L<perlre/Modifiers> for more detail.
5076a392 196
1f539a1a 197=head3 Non-destructive substitution
5076a392 198
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199The substitution (C<s///>) and transliteration
200(C<y///>) operators now support an C</r> option that
201copies the input variable, carries out the substitution on
202the copy and returns the result. The original remains unmodified.
5076a392 203
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204 my $old = 'cat';
205 my $new = $old =~ s/cat/dog/r;
206 # $old is 'cat' and $new is 'dog'
5076a392 207
1f539a1a 208This is particularly useful with C<map>. See L<perlop> for more examples.
5076a392 209
1f539a1a 210=head3 Reentrant regular expression engine
5076a392 211
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212It is now safe to use regular expressions within C<(?{...})> and
213C<(??{...})> code blocks inside regular expressions.
5076a392 214
1f539a1a 215These block are still experimental, however, and still have problems with
e1b1739f 216lexical (C<my>) variables and abnormal exiting.
5076a392 217
1f539a1a 218=head3 C<use re '/flags';>
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219
220The C<re> pragma now has the ability to turn on regular expression flags
221till the end of the lexical scope:
222
223 use re '/x';
224 "foo" =~ / (.+) /; # /x implied
225
226See L<re/"'/flags' mode"> for details.
227
1f539a1a 228=head3 \o{...} for octals
5076a392 229
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230There is a new octal escape sequence, C<"\o">, in double-quote-like
231contexts. This construct allows large octal ordinals beyond the
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232current max of 0777 to be represented. It also allows you to specify a
233character in octal which can safely be concatenated with other regex
234snippets and which won't be confused with being a backreference to
235a regex capture group. See L<perlre/Capture groups>.
236
237=head3 Add C<\p{Titlecase}> as a synonym for C<\p{Title}>
238
239This synonym is added for symmetry with the Unicode property names
240C<\p{Uppercase}> and C<\p{Lowercase}>.
5076a392 241
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242=head3 Regular expression debugging output improvement
243
244Regular expression debugging output (turned on by C<use re 'debug';>) now
245uses hexadecimal when escaping non-ASCII characters, instead of octal.
246
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247=head3 Return value of C<delete $+{...}>
248
249Custom regular expression engines can now determine the return value of
250C<delete> on an entry of C<%+> or C<%->.
251
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252=head2 Syntactical Enhancements
253
254=head3 Array and hash container functions accept references
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255
256All built-in functions that operate directly on array or hash
257containers now also accept hard references to arrays or hashes:
258
259 |----------------------------+---------------------------|
260 | Traditional syntax | Terse syntax |
261 |----------------------------+---------------------------|
262 | push @$arrayref, @stuff | push $arrayref, @stuff |
263 | unshift @$arrayref, @stuff | unshift $arrayref, @stuff |
264 | pop @$arrayref | pop $arrayref |
265 | shift @$arrayref | shift $arrayref |
266 | splice @$arrayref, 0, 2 | splice $arrayref, 0, 2 |
267 | keys %$hashref | keys $hashref |
268 | keys @$arrayref | keys $arrayref |
269 | values %$hashref | values $hashref |
270 | values @$arrayref | values $arrayref |
271 | ($k,$v) = each %$hashref | ($k,$v) = each $hashref |
272 | ($k,$v) = each @$arrayref | ($k,$v) = each $arrayref |
273 |----------------------------+---------------------------|
274
275This allows these built-in functions to act on long dereferencing chains
276or on the return value of subroutines without needing to wrap them in
277C<@{}> or C<%{}>:
278
279 push @{$obj->tags}, $new_tag; # old way
280 push $obj->tags, $new_tag; # new way
281
282 for ( keys %{$hoh->{genres}{artists}} ) {...} # old way
283 for ( keys $hoh->{genres}{artists} ) {...} # new way
284
285For C<push>, C<unshift> and C<splice>, the reference will auto-vivify
286if it is not defined, just as if it were wrapped with C<@{}>.
287
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288For C<keys>, C<values>, C<each>, when overloaded dereferencing is
289present, the overloaded dereference is used instead of dereferencing the
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290underlying reftype. Warnings are issued about assumptions made in
291ambiguous cases.
5076a392 292
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293=head3 Single term prototype
294
295The C<+> prototype is a special alternative to C<$> that will act like
296C<\[@%]> when given a literal array or hash variable, but will otherwise
e1b1739f 297force scalar context on the argument. See L<perlsub/Prototypes>.
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298
299=head3 C<package> block syntax
300
301A package declaration can now contain a code block, in which case the
302declaration is in scope only inside that block. So C<package Foo { ... }>
303is precisely equivalent to C<{ package Foo; ... }>. It also works with
304a version number in the declaration, as in C<package Foo 1.2 { ... }>.
e1b1739f 305See L<perlfunc>.
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306
307=head3 Statement labels can appear in more places
308
309Statement labels can now occur before any type of statement or declaration,
310such as C<package>.
311
312=head3 Stacked labels
313
314Multiple statement labels can now appear before a single statement.
315
316=head3 Uppercase X/B allowed in hexadecimal/binary literals
317
318Literals may now use either upper case C<0X...> or C<0B...> prefixes,
319in addition to the already supported C<0x...> and C<0b...>
e1b1739f 320syntax [perl #76296].
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321
322C, Ruby, Python and PHP already supported this syntax, and it makes
323Perl more internally consistent. A round-trip with C<eval sprintf
e1b1739f 324"%#X", 0x10> now returns C<16>, the way C<eval sprintf "%#x", 0x10> does.
1f539a1a 325
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326=head3 Overridable tie functions
327
328C<tie>, C<tied> and C<untie> can now be overridden [perl #75902].
329
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330=head2 Exception Handling
331
332Several changes have been made to the way C<die>, C<warn>, and C<$@>
333behave, in order to make them more reliable and consistent.
334
335When an exception is thrown inside an C<eval>, the exception is no
336longer at risk of being clobbered by code running during unwinding
337(e.g., destructors). Previously, the exception was written into C<$@>
338early in the throwing process, and would be overwritten if C<eval> was
339used internally in the destructor for an object that had to be freed
340while exiting from the outer C<eval>. Now the exception is written
341into C<$@> last thing before exiting the outer C<eval>, so the code
342running immediately thereafter can rely on the value in C<$@> correctly
343corresponding to that C<eval>. (C<$@> is still also set before exiting the
344C<eval>, for the sake of destructors that rely on this.)
345
346Likewise, a C<local $@> inside an C<eval> will no longer clobber any
347exception thrown in its scope. Previously, the restoration of C<$@> upon
348unwinding would overwrite any exception being thrown. Now the exception
349gets to the C<eval> anyway. So C<local $@> is safe before a C<die>.
350
351Exceptions thrown from object destructors no longer modify the C<$@>
352of the surrounding context. (If the surrounding context was exception
353unwinding, this used to be another way to clobber the exception being
354thrown.) Previously such an exception was
355sometimes emitted as a warning, and then either was
356string-appended to the surrounding C<$@> or completely replaced the
357surrounding C<$@>, depending on whether that exception and the surrounding
358C<$@> were strings or objects. Now, an exception in this situation is
359always emitted as a warning, leaving the surrounding C<$@> untouched.
360In addition to object destructors, this also affects any function call
361performed by XS code using the C<G_KEEPERR> flag.
362
363Warnings for C<warn> can now be objects, in the same way as exceptions
364for C<die>. If an object-based warning gets the default handling,
365of writing to standard error, it is stringified as
366before, with the file and line number appended. But
367a C<$SIG{__WARN__}> handler will now receive an
368object-based warning as an object, where previously it was passed the
369result of stringifying the object.
370
371=head2 Other Enhancements
372
373=head3 Assignment to C<$0> sets the legacy process name with C<prctl()> on Linux
374
12f3ad4e 375On Linux the legacy process name is now set with L<prctl(2)>, in
1f539a1a 376addition to altering the POSIX name via C<argv[0]> as perl has done
12f3ad4e 377since version 4.000. Now system utilities that read the legacy process
1f539a1a 378name such as ps, top and killall will recognize the name you set when
12f3ad4e 379assigning to C<$0>. The string you supply will be cut off at 16 bytes;
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380this is a limitation imposed by Linux.
381
382=head3 C<srand()> now returns the seed
383
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384This allows programs that need to have repeatable results not to have to come
385up with their own seed-generating mechanism. Instead, they can use C<srand()>
386and stash the return value for future use. Typical is a test program which
1f539a1a 387has too many combinations to test comprehensively in the time available to it
e1b1739f 388each run. It can test a random subset each time and, should there be a failure,
1f539a1a 389log the seed used for that run so that it can later be used to reproduce the
e1b1739f 390same results.
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391
392=head3 printf-like functions understand post-1980 size modifiers
393
394Perl's printf and sprintf operators, and Perl's internal printf replacement
395function, now understand the C90 size modifiers "hh" (C<char>), "z"
396(C<size_t>), and "t" (C<ptrdiff_t>). Also, when compiled with a C99
397compiler, Perl now understands the size modifier "j" (C<intmax_t>).
398
399So, for example, on any modern machine, C<sprintf('%hhd', 257)> returns '1'.
400
401=head3 New global variable C<${^GLOBAL_PHASE}>
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402
403A new global variable, C<${^GLOBAL_PHASE}>, has been added to allow
404introspection of the current phase of the perl interpreter. It's explained in
405detail in L<perlvar/"${^GLOBAL_PHASE}"> and
406L<perlmod/"BEGIN, UNITCHECK, CHECK, INIT and END">.
407
1f539a1a 408=head3 C<-d:-foo> calls C<Devel::foo::unimport>
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409
410The syntax C<-dI<B<:>foo>> was extended in 5.6.1 to make C<-dI<:fooB<=bar>>>
411equivalent to C<-MDevel::foo=bar>, which expands
412internally to C<use Devel::foo 'bar';>.
413F<perl> now allows prefixing the module name with C<->, with the same
414semantics as C<-M>, I<i.e.>
415
416=over 4
417
418=item C<-d:-foo>
419
420Equivalent to C<-M-Devel::foo>, expands to
421C<no Devel::foo;>, calls C<< Devel::foo->unimport() >>
422if the method exists.
423
424=item C<-d:-foo=bar>
425
426Equivalent to C<-M-Devel::foo=bar>, expands to C<no Devel::foo 'bar';>,
427calls C<< Devel::foo->unimport('bar') >> if the method exists.
428
429=back
430
e1b1739f 431This is particularly useful for suppressing the default actions of a
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432C<Devel::*> module's C<import> method whilst still loading it for debugging.
433
1f539a1a 434=head3 Filehandle method calls load L<IO::File> on demand
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435
436When a method call on a filehandle would die because the method cannot
437be resolved, and L<IO::File> has not been loaded, Perl now loads L<IO::File>
438via C<require> and attempts method resolution again:
439
440 open my $fh, ">", $file;
441 $fh->binmode(":raw"); # loads IO::File and succeeds
442
443This also works for globs like STDOUT, STDERR and STDIN:
444
445 STDOUT->autoflush(1);
446
447Because this on-demand load only happens if method resolution fails, the
448legacy approach of manually loading an L<IO::File> parent class for partial
449method support still works as expected:
450
451 use IO::Handle;
452 open my $fh, ">", $file;
453 $fh->autoflush(1); # IO::File not loaded
454
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455=head3 IPv6 support
456
457The C<Socket> module provides new affordances for IPv6,
458including implementations of the C<Socket::getaddrinfo()> and
459C<Socket::getnameinfo()> functions, along with related constants, and a
460handful of new functions. See L<Socket>.
461
1f539a1a 462=head3 DTrace probes now include package name
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463
464The DTrace probes now include an additional argument (C<arg3>) which contains
465the package the subroutine being entered or left was compiled in.
466
467For example using the following DTrace script:
468
469 perl$target:::sub-entry
470 {
471 printf("%s::%s\n", copyinstr(arg0), copyinstr(arg3));
472 }
473
474and then running:
475
476 perl -e'sub test { }; test'
477
478DTrace will print:
479
480 main::test
481
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482=head2 New C APIs
483
1e463951 484See L</Internal Changes>.
9378886b 485
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486=head1 Security
487
948b8455 488=head2 User-defined regular expression properties
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489
490In L<perlunicode/"User-Defined Character Properties">, it says you can
491create custom properties by defining subroutines whose names begin with
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492"In" or "Is". However, Perl did not actually enforce that naming
493restriction, so \p{foo::bar} could call foo::bar() if it existed. Now this
948b8455 494convention has been enforced.
5076a392 495
948b8455 496Also, Perl no longer allows a tainted regular expression to invoke a
6369b34f 497user-defined property. It simply dies instead [perl #82616].
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498
499=head1 Incompatible Changes
500
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501Perl 5.14.0 is not binary-compatible with any previous stable release.
502
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503In addition to the sections that follow, see L</C API Changes>.
504
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505=head2 Regular Expressions and String Escapes
506
54c7bb16 507=head3 \400-\777
5076a392 508
54c7bb16 509Use of C<\400>-C<\777> in regexes in certain circumstances has given
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510different, anomalous behavior than their use in all other
511double-quote-like contexts. Since 5.10.1, a deprecated warning message
512has been raised when this happens. Now, all double-quote-like contexts
513have the same behavior, namely to be equivalent to C<\x{100}> -
6369b34f 514C<\x{1FF}>, with no deprecation warning. Use of these values in the
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515command line option C<"-0"> retains the current meaning to slurp input
516files whole; previously, this was documented only for C<"-0777">. It is
517recommended, however, because of various ambiguities, to use the new
518C<\o{...}> construct to represent characters in octal.
5076a392 519
61752d82 520=head3 Most C<\p{}> properties are now immune to case-insensitive matching
5076a392 521
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522For most Unicode properties, it doesn't make sense to have them match
523differently under C</i> case-insensitive matching than not. And doing
524so leads to unexpected results and potential security holes. For
525example
5076a392 526
61752d82 527 m/\p{ASCII_Hex_Digit}+/i
5076a392 528
61752d82 529could previously match non-ASCII characters because of the Unicode
4cf6a51f
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530matching rules (although there were a number of bugs with this). Now
531matching under C</i> gives the same results as non-C</i> matching except
532for those few properties where people have come to expect differences,
533namely the ones where casing is an integral part of their meaning, such
534as C<m/\p{Uppercase}/i> and C<m/\p{Lowercase}/i>, both of which match
535the exact same code points, namely those matched by C<m/\p{Cased}/i>.
536Details are in L<perlrecharclass/Unicode Properties>.
5076a392 537
61752d82 538User-defined property handlers that need to match differently under
4cf6a51f 539C</i> must change to read the new boolean parameter passed to them which is
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540non-zero if case-insensitive matching is in effect or 0 otherwise. See
541L<perluniprops/User-Defined Character Properties>.
5076a392 542
61752d82 543=head3 \p{} implies Unicode semantics
5076a392 544
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545Now, a Unicode property match specified in the pattern will indicate
546that the pattern is meant for matching according to Unicode rules, the way
bc15a0a0 547C<\N{}> does.
5076a392 548
61752d82 549=head3 Regular expressions retain their localeness when interpolated
5076a392 550
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551Regular expressions compiled under C<"use locale"> now retain this when
552interpolated into a new regular expression compiled outside a
553C<"use locale">, and vice-versa.
5076a392 554
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555Previously, a regular expression interpolated into another one inherited
556the localeness of the surrounding one, losing whatever state it
557originally had. This is considered a bug fix, but may trip up code that
558has come to rely on the incorrect behavior.
5076a392 559
61752d82 560=head3 Stringification of regexes has changed
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561
562Default regular expression modifiers are now notated by using
563C<(?^...)>. Code relying on the old stringification will fail. The
564purpose of this is so that when new modifiers are added, such code will
565not have to change (after this one time), as the stringification will
566automatically incorporate the new modifiers.
567
568Code that needs to work properly with both old- and new-style regexes
f318e2e6 569can avoid the whole issue by using (for Perls since 5.9.5; see L<re>):
5076a392
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570
571 use re qw(regexp_pattern);
572 my ($pat, $mods) = regexp_pattern($re_ref);
573
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574If the actual stringification is important, or older Perls need to be
575supported, you can use something like the following:
576
577 # Accept both old and new-style stringification
578 my $modifiers = (qr/foobar/ =~ /\Q(?^/) ? '^' : '-xism';
579
580And then use C<$modifiers> instead of C<-xism>.
581
61752d82 582=head3 Run-time code blocks in regular expressions inherit pragmata
5076a392 583
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584Code blocks in regular expressions (C<(?{...})> and C<(??{...})>) used not
585to inherit any pragmata (strict, warnings, etc.) if the regular expression
586was compiled at run time as happens in cases like these two:
5076a392 587
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588 use re 'eval';
589 $foo =~ $bar; # when $bar contains (?{...})
590 $foo =~ /$bar(?{ $finished = 1 })/;
591
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592This was a bug, which has now been fixed. But
593it has the potential to break
61752d82 594any code that was relying on it.
5076a392 595
61752d82 596=head2 Stashes and Package Variables
5076a392 597
61752d82 598=head3 Localised tied hashes and arrays are no longed tied
5076a392 599
61752d82 600In the following:
5076a392 601
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602 tie @a, ...;
603 {
604 local @a;
605 # here, @a is a now a new, untied array
606 }
607 # here, @a refers again to the old, tied array
5076a392 608
61752d82 609The new local array used to be made tied too, which was fairly pointless,
6369b34f 610and has now been fixed. This fix could however potentially cause a change
61752d82 611in behaviour of some code.
5076a392 612
61752d82 613=head3 Stashes are now always defined
5076a392 614
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615C<defined %Foo::> now always returns true, even when no symbols have yet been
616defined in that package.
5076a392 617
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618This is a side effect of removing a special case kludge in the tokeniser,
619added for 5.10.0, to hide side effects of changes to the internal storage of
620hashes that drastically reduce their memory usage overhead.
621
622Calling defined on a stash has been deprecated since 5.6.0, warned on
623lexicals since 5.6.0, and warned for stashes (and other package
6369b34f 624variables) since 5.12.0. C<defined %hash> has always exposed an
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625implementation detail - emptying a hash by deleting all entries from it does
626not make C<defined %hash> false, hence C<defined %hash> is not valid code to
6369b34f 627determine whether an arbitrary hash is empty. Instead, use the behaviour
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628that an empty C<%hash> always returns false in a scalar context.
629
48b31689
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630=head3 Clearing stashes
631
632Stash list assignment C<%foo:: = ()> used to make the stash anonymous
633temporarily while it was being emptied. Consequently, any of its
634subroutines referenced elsewhere would become anonymous (showing up as
635"(unknown)" in C<caller>). Now they retain their package names, such that
636C<caller> will return the original sub name if there is still a reference
637to its typeglob, or "foo::__ANON__" otherwise [perl #79208].
638
61752d82 639=head3 Dereferencing typeglobs
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640
641If you assign a typeglob to a scalar variable:
642
643 $glob = *foo;
644
645the glob that is copied to C<$glob> is marked with a special flag
6369b34f
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646indicating that the glob is just a copy. This
647allows subsequent assignments to C<$glob> to
648overwrite the glob. The original glob, however, is
5076a392
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649immutable.
650
370ff23e 651Some Perl operators did not distinguish between these two types of globs.
5076a392 652This would result in strange behaviour in edge cases: C<untie $scalar>
370ff23e 653would not untie the scalar if the last thing assigned to it was a glob
5076a392 654(because it treated it as C<untie *$scalar>, which unties a handle).
f318e2e6 655Assignment to a glob slot (e.g., C<*$glob = \@some_array>) would simply
5076a392
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656assign C<\@some_array> to C<$glob>.
657
658To fix this, the C<*{}> operator (including the C<*foo> and C<*$foo> forms)
659has been modified to make a new immutable glob if its operand is a glob
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FC
660copy. This allows operators that make a distinction between globs and
661scalars to be modified to treat only immutable globs as globs. (C<tie>,
662C<tied> and C<untie> have been left as they are for compatibility's sake,
6369b34f 663but will warn. See L</Deprecations>.)
5076a392
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664
665This causes an incompatible change in code that assigns a glob to the
6369b34f 666return value of C<*{}> when that operator was passed a glob copy. Take the
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667following code, for instance:
668
669 $glob = *foo;
670 *$glob = *bar;
671
672The C<*$glob> on the second line returns a new immutable glob. That new
6369b34f 673glob is made an alias to C<*bar>. Then it is discarded. So the second
5076a392
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674assignment has no effect.
675
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676See L<http://rt.perl.org/rt3/Public/Bug/Display.html?id=77810> for even
677more detail.
678
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679=head3 Magic variables outside the main package
680
681In previous versions of Perl, magic variables like C<$!>, C<%SIG>, etc. would
682'leak' into other packages. So C<%foo::SIG> could be used to access signals,
683C<${"foo::!"}> (with strict mode off) to access C's C<errno>, etc.
684
685This was a bug, or an 'unintentional' feature, which caused various ill effects,
686such as signal handlers being wiped when modules were loaded, etc.
687
688This has been fixed (or the feature has been removed, depending on how you see
689it).
690
691=head2 Changes to Syntax or to Perl Operators
692
693=head3 C<given> return values
694
695C<given> blocks now return the last evaluated
696expression, or an empty list if the block was exited by C<break>. Thus you
697can now write:
698
699 my $type = do {
700 given ($num) {
701 break when undef;
702 'integer' when /^[+-]?[0-9]+$/;
703 'float' when /^[+-]?[0-9]+(?:\.[0-9]+)?$/;
704 'unknown';
705 }
706 };
707
708See L<perlsyn/Return value> for details.
709
710=head3 Change in the parsing of certain prototypes
711
712Functions declared with the following prototypes now behave correctly as unary
713functions:
714
715 *
716 \$ \% \@ \* \&
717 \[...]
718 ;$ ;*
719 ;\$ ;\% etc.
720 ;\[...]
721
722Due to this bug fix [perl #75904], functions
723using the C<(*)>, C<(;$)> and C<(;*)> prototypes
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FC
724are parsed with higher precedence than before. So
725in the following example:
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726
727 sub foo($);
728 foo $a < $b;
729
730the second line is now parsed correctly as C<< foo($a) < $b >>, rather than
179813a8 731C<< foo($a < $b) >>. This happens when one of these operators is used in
61752d82
FC
732an unparenthesised argument:
733
734 < > <= >= lt gt le ge
735 == != <=> eq ne cmp ~~
736 &
737 | ^
738 &&
739 || //
740 .. ...
741 ?:
742 = += -= *= etc.
743
744=head3 Smart-matching against array slices
745
746Previously, the following code resulted in a successful match:
747
748 my @a = qw(a y0 z);
749 my @b = qw(a x0 z);
750 @a[0 .. $#b] ~~ @b;
751
752This odd behaviour has now been fixed [perl #77468].
753
754=head3 Negation treats strings differently from before
755
756The unary negation operator C<-> now treats strings that look like numbers
757as numbers [perl #57706].
758
759=head3 Negative zero
760
761Negative zero (-0.0), when converted to a string, now becomes "0" on all
179813a8 762platforms. It used to become "-0" on some, but "0" on others.
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763
764If you still need to determine whether a zero is negative, use
765C<sprintf("%g", $zero) =~ /^-/> or the L<Data::Float> module on CPAN.
766
767=head3 C<:=> is now a syntax error
5076a392
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768
769Previously C<my $pi := 4;> was exactly equivalent to C<my $pi : = 4;>,
770with the C<:> being treated as the start of an attribute list, ending before
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FC
771the C<=>. The use of C<:=> to mean C<: => was deprecated in 5.12.0, and is
772now a syntax error. This will allow the future use of C<:=> as a new
773token.
5076a392
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774
775We find no Perl 5 code on CPAN using this construction, outside the core's
776tests for it, so we believe that this change will have very little impact on
777real-world codebases.
778
779If it is absolutely necessary to have empty attribute lists (for example,
780because of a code generator) then avoid the error by adding a space before
781the C<=>.
782
61752d82 783=head2 Threads and Processes
5076a392 784
61752d82 785=head3 Directory handles not copied to threads
5076a392 786
61752d82
FC
787On systems other than Windows that do not have
788a C<fchdir> function, newly-created threads no
179813a8 789longer inherit directory handles from their parent threads. Such programs
61752d82 790would usually have crashed anyway [perl #75154].
5076a392 791
61752d82 792=head3 C<close> on shared pipes
5076a392 793
61752d82
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794The C<close> function no longer waits for the child process to exit if the
795underlying file descriptor is still in use by another thread, to avoid
179813a8 796deadlocks. It returns true in such cases.
5076a392 797
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798=head3 fork() emulation will not wait for signalled children
799
800On Windows parent processes would not terminate until all forked
801childred had terminated first. However, C<kill('KILL', ...)> is
802inherently unstable on pseudo-processes, and C<kill('TERM', ...)>
179813a8 803might not get delivered if the child is blocked in a system call.
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FC
804
805To avoid the deadlock and still provide a safe mechanism to terminate
806the hosting process, Perl will now no longer wait for children that
807have been sent a SIGTERM signal. It is up to the parent process to
808waitpid() for these children if child clean-up processing must be
179813a8 809allowed to finish. However, it is also the responsibility of the
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810parent then to avoid the deadlock by making sure the child process
811can't be blocked on I/O either.
812
813See L<perlfork> for more information about the fork() emulation on
814Windows.
815
61752d82 816=head2 Configuration
5076a392 817
61752d82 818=head3 Naming fixes in Policy_sh.SH may invalidate Policy.sh
5076a392 819
61752d82
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820Several long-standing typos and naming confusions in Policy_sh.SH have
821been fixed, standardizing on the variable names used in config.sh.
5076a392 822
61752d82 823This will change the behavior of Policy.sh if you happen to have been
179813a8 824accidentally relying on its incorrect behavior.
f318e2e6 825
5a1f7719
FC
826=head3 Perl source code is read in text mode on Windows
827
828Perl scripts used to be read in binary mode on Windows for the benefit
829of the ByteLoader module (which is no longer part of core Perl). This
830had the side effect of breaking various operations on the DATA filehandle,
831including seek()/tell(), and even simply reading from DATA after file handles
832have been flushed by a call to system(), backticks, fork() etc.
833
834The default build options for Windows have been changed to read Perl source
835code on Windows in text mode now. Hopefully ByteLoader will be updated on
836CPAN to automatically handle this situation [perl #28106].
837
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838=head1 Deprecations
839
1e463951
FC
840See also L</Deprecated C APIs>.
841
5076a392
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842=head2 Omitting a space between a regular expression and subsequent word
843
18139a1b
FC
844Omitting a space between a regular expression operator or
845its modifiers and the following word is deprecated. For
846example, C<< m/foo/sand $bar >> will still be parsed
847as C<< m/foo/s and $bar >> but will issue a warning.
5076a392 848
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849=head2 C<\cI<X>>
850
851The backslash-c construct was designed as a way of specifying
852non-printable characters, but there were no restrictions (on ASCII
853platforms) on what the character following the C<c> could be. Now,
854a deprecation warning is raised if that character isn't an ASCII character.
855Also, a deprecation warning is raised for C<"\c{"> (which is the same
856as simply saying C<";">).
857
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858=head2 C<"\b{"> and C<"\B{">
859
860In regular expressions, a literal C<"{"> immediately following a C<"\b">
861(not in a bracketed character class) or a C<"\B{"> is now deprecated
862to allow for its future use by Perl itself.
863
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864=head2 Deprecation warning added for deprecated-in-core .pl libs
865
866This is a mandatory warning, not obeying -X or lexical warning bits.
867The warning is modelled on that supplied by deprecate.pm for
868deprecated-in-core .pm libraries. It points to the specific CPAN
823d0e46
FC
869distribution that contains the .pl libraries. The CPAN version, of
870course, does not generate the warning.
5076a392
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871
872=head2 List assignment to C<$[>
873
823d0e46
FC
874Assignment to C<$[> was deprecated and started to give warnings in
875Perl version 5.12.0. This version of perl also starts to emit a warning when
876assigning to C<$[> in list context. This fixes an oversight in 5.12.0.
5076a392
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877
878=head2 Use of qw(...) as parentheses
879
880Historically the parser fooled itself into thinking that C<qw(...)> literals
881were always enclosed in parentheses, and as a result you could sometimes omit
882parentheses around them:
883
884 for $x qw(a b c) { ... }
885
886The parser no longer lies to itself in this way. Wrap the list literal in
823d0e46 887parentheses, like this:
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888
889 for $x (qw(a b c)) { ... }
890
891=head2 C<\N{BELL}> is deprecated
892
893This is because Unicode is using that name for a different character.
894See L</Unicode Version 6.0 is now supported (mostly)> for more
895explanation.
896
897=head2 C<?PATTERN?> is deprecated
898
899C<?PATTERN?> (without the initial m) has been deprecated and now produces
900a warning. This is to allow future use of C<?> in new operators.
901The match-once functionality is still available in the form of C<m?PATTERN?>.
902
5076a392
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903=head2 Tie functions on scalars holding typeglobs
904
905Calling a tie function (C<tie>, C<tied>, C<untie>) with a scalar argument
906acts on a file handle if the scalar happens to hold a typeglob.
907
908This is a long-standing bug that will be removed in Perl 5.16, as
909there is currently no way to tie the scalar itself when it holds
910a typeglob, and no way to untie a scalar that has had a typeglob
911assigned to it.
912
823d0e46 913Now there is a deprecation warning whenever a tie
5076a392
FC
914function is used on a handle without an explicit C<*>.
915
18139a1b 916=head2 User-defined case-mapping
5076a392 917
18139a1b
FC
918This feature is being deprecated due to its many issues, as documented in
919L<perlunicode/User-Defined Case Mappings (for serious hackers only)>.
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920It is planned to remove this feature in Perl 5.16. Instead use the CPAN module
921L<Unicode::Casing>, which provides improved functionality.
823d0e46 922
18139a1b 923=head2 Deprecated modules
5076a392
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924
925The following modules will be removed from the core distribution in a
926future release, and should be installed from CPAN instead. Distributions
a60ea503 927on CPAN which require these should add them to their prerequisites. The
823d0e46 928core versions of these modules will issue a deprecation warning.
5076a392
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929
930If you ship a packaged version of Perl, either alone or as part of a
931larger system, then you should carefully consider the repercussions of
823d0e46 932core module deprecations. You may want to consider shipping your default
5076a392 933build of Perl with packages for some or all deprecated modules which
823d0e46 934install into C<vendor> or C<site> perl library directories. This will
5076a392
FC
935inhibit the deprecation warnings.
936
937Alternatively, you may want to consider patching F<lib/deprecate.pm>
938to provide deprecation warnings specific to your packaging system
939or distribution of Perl, consistent with how your packaging system
940or distribution manages a staged transition from a release where the
941installation of a single package provides the given functionality, to
942a later release where the system administrator needs to know to install
943multiple packages to get that same functionality.
944
945You can silence these deprecation warnings by installing the modules
946in question from CPAN. To install the latest version of all of them,
947just install C<Task::Deprecations::5_14>.
948
949=over
950
951=item L<Devel::DProf>
952
953We strongly recommend that you install and used L<Devel::NYTProf> in
954preference, as it offers significantly improved profiling and reporting.
955
956=back
957
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958=head1 Performance Enhancements
959
54c7bb16 960=head2 "Safe signals" optimisation
df91d470 961
a60ea503 962Signal dispatch has been moved from the runloop into control ops. This
df91d470
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963should give a few percent speed increase, and eliminates almost all of
964the speed penalty caused by the introduction of "safe signals" in
a60ea503 9655.8.0. Signals should still be dispatched within the same statement as
df91d470
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966they were previously - if this is not the case, or it is possible to
967create uninterruptible loops, this is a bug, and reports are encouraged
968of how to recreate such issues.
969
54c7bb16 970=head2 Optimisation of shift; and pop; calls without arguments
df91d470 971
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972Two fewer OPs are used for shift and pop calls with no argument (with
973implicit C<@_>). This change makes C<shift;> 5% faster than C<shift @_;>
974on non-threaded perls and 25% faster on threaded.
df91d470 975
fa232254 976=head2 Optimisation of regexp engine string comparison work
df91d470 977
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978The foldEQ_utf8 API function for case-insensitive comparison of strings (which
979is used heavily by the regexp engine) was substantially refactored and
980optimised - and its documentation much improved as a free bonus gift.
df91d470 981
fa232254 982=head2 Regular expression compilation speed-up
df91d470 983
fa232254
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984Compiling regular expressions has been made faster for the case where upgrading
985the regex to utf8 is necessary but that isn't known when the compilation begins.
df91d470 986
fa232254 987=head2 String appending is 100 times faster
df91d470 988
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989When doing a lot of string appending, perl could end up allocating a lot more
990memory than needed in a very inefficient way, if perl was configured to use the
991system's C<malloc> implementation instead of its own.
992
993C<sv_grow>, which is what's being used to allocate more memory if necessary
994when appending to a string, has now been taught how to round up the memory
995it requests to a certain geometric progression, making it much faster on
996certain platforms and configurations. On Win32, it's now about 100 times
997faster.
998
999=head2 Eliminate C<PL_*> accessor functions under ithreads
1000
1001When C<MULTIPLICITY> was first developed, and interpreter state moved into
1002an interpreter struct, thread and interpreter local C<PL_*> variables were
1003defined as macros that called accessor functions, returning the address of
1004the value, outside of the perl core. The intent was to allow members
1005within the interpreter struct to change size without breaking binary
1006compatibility, so that bug fixes could be merged to a maintenance branch
1007that necessitated such a size change.
1008
1009However, some non-core code defines C<PERL_CORE>, sometimes intentionally
1010to bypass this mechanism for speed reasons, sometimes for other reasons but
1011with the inadvertent side effect of bypassing this mechanism. As some of
1012this code is widespread in production use, the result is that the core
1013I<can't> change the size of members of the interpreter struct, as it will
1014break such modules compiled against a previous release on that maintenance
1015branch. The upshot is that this mechanism is redundant, and well-behaved
1016code is penalised by it. Hence it can and should be removed (and has
1017been).
1018
1019=head2 Freeing weak references
1020
1021When an object has many weak references to it, freeing that object
1022can under some some circumstances take O(N^2) time to free (where N is the
a60ea503 1023number of references). The number of circumstances has been reduced
fa232254
FC
1024[perl #75254]
1025
1026=head2 Lexical array and hash assignments
1027
1028An earlier optimisation to speed up C<my @array = ...> and
1029C<my %hash = ...> assignments caused a bug and was disabled in Perl 5.12.0.
1030
1031Now we have found another way to speed up these assignments [perl #82110].
df91d470 1032
111b6aa7 1033=head2 C<@_> uses less memory
df91d470 1034
111b6aa7
FC
1035Previously, C<@_> was allocated for every subroutine at compile time with
1036enough space for four entries. Now this allocation is done on demand when
1037the subroutine is called [perl #72416].
5076a392 1038
5076a392
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1039=head2 Size optimisations to SV and HV structures
1040
1041xhv_fill has been eliminated from struct xpvhv, saving 1 IV per hash and
a60ea503 1042on some systems will cause struct xpvhv to become cache-aligned. To avoid
5076a392
FC
1043this memory saving causing a slowdown elsewhere, boolean use of HvFILL
1044now calls HvTOTALKEYS instead (which is equivalent) - so while the fill
111b6aa7
FC
1045data when actually required are now calculated on demand, the cases when
1046this needs to be done should be few and far between.
5076a392 1047
111b6aa7
FC
1048The order of structure elements in SV bodies has changed. Effectively,
1049the NV slot has swapped location with STASH and MAGIC. As all access to
1050SV members is via macros, this should be completely transparent. This
5076a392
FC
1051change allows the space saving for PVHVs documented above, and may reduce
1052the memory allocation needed for PVIVs on some architectures.
1053
fa232254
FC
1054C<XPV>, C<XPVIV>, and C<XPVNV> now only allocate the parts of the C<SV> body
1055they actually use, saving some space.
5076a392 1056
fa232254
FC
1057Scalars containing regular expressions now only allocate the part of the C<SV>
1058body they actually use, saving some space.
5076a392
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1059
1060=head2 Memory consumption improvements to Exporter
1061
1062The @EXPORT_FAIL AV is no longer created unless required, hence neither is
111b6aa7
FC
1063the typeglob backing it. This saves about 200 bytes for every package that
1064uses Exporter but doesn't use this functionality.
5076a392 1065
111b6aa7 1066=head2 Memory savings for weak references
5076a392
FC
1067
1068For weak references, the common case of just a single weak reference per
a60ea503
FC
1069referent has been optimised to reduce the
1070storage required. In this case it
111b6aa7 1071saves the equivalent of one small Perl array per referent.
5076a392 1072
111b6aa7 1073=head2 C<%+> and C<%-> use less memory
5076a392
FC
1074
1075The bulk of the C<Tie::Hash::NamedCapture> module used to be in the perl
111b6aa7 1076core. It has now been moved to an XS module, to reduce the overhead for
5076a392
FC
1077programs that do not use C<%+> or C<%->.
1078
fa232254 1079=head2 Multiple small improvements to threads
5076a392 1080
fa232254
FC
1081The internal structures of threading now make fewer API calls and fewer
1082allocations, resulting in noticeably smaller object code. Additionally,
1083many thread context checks have been deferred so that they're only done
1084when required (although this is only possible for non-debugging builds).
5076a392 1085
fa232254 1086=head2 Adjacent pairs of nextstate opcodes are now optimized away
5076a392 1087
fa232254 1088Previously, in code such as
5076a392 1089
fa232254 1090 use constant DEBUG => 0;
5076a392 1091
fa232254
FC
1092 sub GAK {
1093 warn if DEBUG;
1094 print "stuff\n";
1095 }
5076a392 1096
fa232254
FC
1097the ops for C<warn if DEBUG;> would be folded to a C<null> op (C<ex-const>), but
1098the C<nextstate> op would remain, resulting in a runtime op dispatch of
1099C<nextstate>, C<nextstate>, ....
5076a392 1100
fa232254
FC
1101The execution of a sequence of C<nextstate> ops is indistinguishable from just
1102the last C<nextstate> op so the peephole optimizer now eliminates the first of
1103a pair of C<nextstate> ops, except where the first carries a label, since labels
1104must not be eliminated by the optimizer and label usage isn't conclusively known
1105at compile time.
5076a392
FC
1106
1107=head1 Modules and Pragmata
1108
1109=head2 New Modules and Pragmata
1110
1111=over 4
1112
1113=item *
1114
1115C<CPAN::Meta::YAML> 0.003 has been added as a dual-life module. It supports a
1116subset of YAML sufficient for reading and writing META.yml and MYMETA.yml files
1117included with CPAN distributions or generated by the module installation
a60ea503 1118toolchain. It should not be used for any other general YAML parsing or
5076a392
FC
1119generation task.
1120
1121=item *
1122
a60ea503 1123C<CPAN::Meta> version 2.110440 has been added as a dual-life module. It
5076a392
FC
1124provides a standard library to read, interpret and write CPAN distribution
1125metadata files (e.g. META.json and META.yml) which describes a
1126distribution, its contents, and the requirements for building it and
a60ea503 1127installing it. The latest CPAN distribution metadata specification is
5076a392
FC
1128included as C<CPAN::Meta::Spec> and notes on changes in the specification
1129over time are given in C<CPAN::Meta::History>.
1130
1131=item *
1132
5a553547 1133C<HTTP::Tiny> 0.011 has been added as a dual-life module. It is a very
5076a392
FC
1134small, simple HTTP/1.1 client designed for simple GET requests and file
1135mirroring. It has has been added to enable CPAN.pm and CPANPLUS to
1136"bootstrap" HTTP access to CPAN using pure Perl without relying on external
1137binaries like F<curl> or F<wget>.
1138
1139=item *
1140
1141C<JSON::PP> 2.27105 has been added as a dual-life module, for the sake of
1142reading F<META.json> files in CPAN distributions.
1143
1144=item *
1145
21ef4e45 1146C<Module::Metadata> 1.000004 has been added as a dual-life module. It gathers
5076a392
FC
1147package and POD information from Perl module files. It is a standalone module
1148based on Module::Build::ModuleInfo for use by other module installation
1149toolchain components. Module::Build::ModuleInfo has been deprecated in
1150favor of this module instead.
1151
1152=item *
1153
1154C<Perl::OSType> 1.002 has been added as a dual-life module. It maps Perl
1155operating system names (e.g. 'dragonfly' or 'MSWin32') to more generic types
1156with standardized names (e.g. "Unix" or "Windows"). It has been refactored
1157out of Module::Build and ExtUtils::CBuilder and consolidates such mappings into
1158a single location for easier maintenance.
1159
1160=item *
1161
1162The following modules were added by the C<Unicode::Collate>
a60ea503 1163upgrade. See below for details.
5076a392
FC
1164
1165C<Unicode::Collate::CJK::Big5>
1166
1167C<Unicode::Collate::CJK::GB2312>
1168
1169C<Unicode::Collate::CJK::JISX0208>
1170
1171C<Unicode::Collate::CJK::Korean>
1172
1173C<Unicode::Collate::CJK::Pinyin>
1174
1175C<Unicode::Collate::CJK::Stroke>
1176
1177=item *
1178
1179C<Version::Requirements> version 0.101020 has been added as a dual-life
1180module. It provides a standard library to model and manipulates module
1181prerequisites and version constraints as defined in the L<CPAN::Meta::Spec>.
1182
1183=back
1184
a5794e94 1185=head2 Updated Modules and Pragma
5076a392
FC
1186
1187=over 4
1188
1189=item *
1190
81a53be2
FR
1191C<attributes> has been upgraded from version 0.12 to 0.14.
1192
1193=item *
1194
5076a392
FC
1195C<Archive::Extract> has been upgraded from version 0.38 to 0.48.
1196
1197Updates since 0.38 include: a safe print method that guards
1198Archive::Extract from changes to $\; a fix to the tests when run in core
1984204c
FC
1199perl; support for TZ files; a modification for the lzma
1200logic to favour IO::Uncompress::Unlzma; and a fix
1201for an issue with NetBSD-current and its new unzip
5076a392
FC
1202executable.
1203
1204=item *
1205
1206C<Archive::Tar> has been upgraded from version 1.54 to 1.76.
1207
1984204c
FC
1208Important changes since 1.54 include the following:
1209
1210=over
1211
1212=item *
1213
1214Compatibility with busybox implementations of tar
1215
1216=item *
1217
1218A fix so that C<write()> and C<create_archive()>
1219close only handles they opened
1220
1221=item *
1222
1223A bug was fixed regarding the exit code of extract_archive.
5076a392 1224
1984204c
FC
1225=item *
1226
4f978a3b 1227The C<ptar> utility has a new option to allow safe
5076a392
FC
1228creation of tarballs without world-writable files on Windows, allowing those
1229archives to be uploaded to CPAN.
1230
1984204c
FC
1231=item *
1232
1233A new ptargrep utility for using regular expressions against
5076a392
FC
1234the contents of files in a tar archive.
1235
1984204c
FC
1236=item *
1237
1238Pax extended headers are now skipped.
1239
1240=back
5076a392
FC
1241
1242=item *
1243
fcd5df6d
FR
1244C<Attribute::Handlers> has been upgraded from version 0.87 to 0.89.
1245
1246=item *
1247
3f5a47e4
FR
1248C<autodie> has been upgraded from version 2.06_01 to 2.1001.
1249
1250=item *
1251
578e7c9d
FR
1252C<AutoLoader> has been upgraded from version 5.70 to 5.71.
1253
1254=item *
1255
a13baafd 1256C<B> has been upgraded from version 1.23 to 1.29.
5076a392
FC
1257
1258It no longer crashes when taking apart a C<y///> containing characters
1259outside the octet range or compiled in a C<use utf8> scope.
1260
1261The size of the shared object has been reduced by about 40%, with no
1262reduction in functionality.
1263
1264=item *
1265
4a75fbf5 1266C<B::Concise> has been upgraded from version 0.78 to 0.83.
5076a392
FC
1267
1268B::Concise marks rv2sv, rv2av and rv2hv ops with the new OPpDEREF flag
1269as "DREFed".
1270
1271It no longer produces mangled output with the C<-tree> option
1272[perl #80632].
1273
1274=item *
1275
6bb8c1e3
FR
1276C<B::Debug> has been upgraded from version 1.12 to 1.16.
1277
1278=item *
1279
c67a4e29 1280C<B::Deparse> has been upgraded from version 0.96 to 1.03.
5076a392 1281
1984204c 1282The deparsing of a nextstate op has changed when it has both a
5076a392
FC
1283change of package (relative to the previous nextstate), or a change of
1284C<%^H> or other state, and a label. Previously the label was emitted
cdc10f43 1285first, but now the label is emitted last (5.12.1).
5076a392 1286
5a553547
FC
1287The C<no 5.13.2> or similar form is now correctly handled by B::Deparse
1288(5.12.3).
5076a392
FC
1289
1290B::Deparse now properly handles the code that applies a conditional
1291pattern match against implicit C<$_> as it was fixed in [perl #20444].
1292
1984204c
FC
1293Deparsing of C<our> followed by a variable with funny characters
1294(as permitted under the C<utf8> pragma) has also been fixed [perl #33752].
5076a392
FC
1295
1296=item *
1297
d97c5d3b
FR
1298C<B::Lint> has been upgraded from version 1.11_01 to 1.13.
1299
1300=item *
1301
5aef2c44
FR
1302C<base> has been upgraded from version 2.15 to 2.16.
1303
1304=item *
1305
876607aa
FR
1306C<Benchmark> has been upgraded from version 1.11 to 1.12.
1307
1308=item *
1309
e539ae69
FR
1310C<bignum> has been upgraded from version 0.23 to 0.26.
1311
1312=item *
1313
c74c1fa8 1314C<Carp> has been upgraded from version 1.15 to 1.20.
5076a392
FC
1315
1316L<Carp> now detects incomplete L<caller()|perlfunc/"caller EXPR"> overrides and
d430b8e7
FC
1317avoids using bogus C<@DB::args>. To provide backtraces,
1318Carp relies on particular behaviour of the C<caller>
1319built-in. Carp now detects if other code has
5076a392 1320overridden this with an incomplete implementation, and modifies its backtrace
d430b8e7
FC
1321accordingly. Previously incomplete overrides would cause incorrect values
1322in backtraces (best case), or obscure fatal errors (worst case).
5076a392
FC
1323
1324This fixes certain cases of C<Bizarre copy of ARRAY> caused by modules
d430b8e7 1325overriding C<caller()> incorrectly (5.12.2).
5076a392 1326
1984204c 1327It now also avoids using regular expressions that cause perl to
5076a392
FC
1328load its Unicode tables, in order to avoid the 'BEGIN not safe after
1329errors' error that will ensue if there has been a syntax error
1330[perl #82854].
1331
1332=item *
1333
9eb7ad55 1334C<CGI> has been upgraded from version 3.48 to 3.52.
5076a392
FC
1335
1336This provides the following security fixes: the MIME boundary in
1984204c
FC
1337multipart_init is now random and the handling of
1338newlines embedded in header values has been improved.
5076a392
FC
1339
1340=item *
1341
5076a392
FC
1342C<Compress::Raw::Bzip2> has been upgraded from version 2.024 to 2.033.
1343
1984204c 1344It has been updated to use bzip2 1.0.6.
5076a392
FC
1345
1346=item *
1347
51090521
FR
1348C<Compress::Raw::Zlib> has been upgraded from version 2.024 to 2.033.
1349
1350=item *
1351
f75b7efc 1352C<CPAN> has been upgraded from version 1.94_56 to 1.9600.
1984204c
FC
1353
1354Major highlights:
5076a392
FC
1355
1356=over 4
1357
1984204c 1358=item * much less configuration dialog hassle
5076a392 1359
1984204c 1360=item * support for META/MYMETA.json
5076a392 1361
1984204c 1362=item * support for local::lib
5076a392 1363
1984204c 1364=item * support for HTTP::Tiny to reduce the dependency on ftp sites
5076a392 1365
1984204c 1366=item * automatic mirror selection
5076a392 1367
1984204c 1368=item * iron out all known bugs in configure_requires
5076a392 1369
1984204c
FC
1370=item * support for distributions compressed with bzip2
1371
1372=item * allow Foo/Bar.pm on the commandline to mean Foo::Bar
1373
1374=back
5076a392
FC
1375
1376=item *
1377
d430b8e7
FC
1378C<CPANPLUS> has been upgraded from version 0.90 to 0.9103.
1379
1380A change to F<cpanp-run-perl>
1381resolves L<RT #55964|http://rt.cpan.org/Public/Bug/Display.html?id=55964>
1382and L<RT #57106|http://rt.cpan.org/Public/Bug/Display.html?id=57106>, both
1383of which related to failures to install distributions that use
1384C<Module::Install::DSL> (5.12.2).
5076a392 1385
1984204c
FC
1386A dependency on Config was not recognised as a
1387core module dependency. This has been fixed.
5076a392 1388
1984204c 1389CPANPLUS now includes support for META.json and MYMETA.json.
5076a392
FC
1390
1391=item *
1392
4467e8f7
FR
1393C<CPANPLUS::Dist::Build> has been upgraded from version 0.46 to 0.54.
1394
1395=item *
1396
5076a392
FC
1397C<Data::Dumper> has been upgraded from version 2.125 to 2.130_02.
1398
4ed2cea4
FC
1399The indentation used to be off when C<$Data::Dumper::Terse> was set. This
1400has been fixed [perl #73604].
1401
1984204c
FC
1402This upgrade also fixes a crash when using custom sort functions that might
1403cause the stack to change [perl #74170].
5076a392
FC
1404
1405C<Dumpxs> no longer crashes with globs returned by C<*$io_ref>
1406[perl #72332].
1407
1408=item *
1409
549d34f5
FR
1410C<DB_File> has been upgraded from version 1.820 to 1.821.
1411
1412=item *
1413
851dbda2
FR
1414C<DBM_Filter> has been upgraded from version 0.03 to 0.04.
1415
1416=item *
1417
5076a392
FC
1418C<Devel::DProf> has been upgraded from version 20080331.00 to 20110228.00.
1419
1420Merely loading C<Devel::DProf> now no longer triggers profiling to start.
1421C<use Devel::DProf> and C<perl -d:DProf ...> still behave as before and start
1422the profiler.
1423
1424NOTE: C<Devel::DProf> is deprecated and will be removed from a future
1984204c 1425version of Perl. We strongly recommend that you install and use
5076a392
FC
1426L<Devel::NYTProf> instead, as it offers significantly improved
1427profiling and reporting.
1428
1429=item *
1430
868625d2
FR
1431C<Devel::Peek> has been upgraded from version 1.04 to 1.07.
1432
1433=item *
1434
66899ca3
FR
1435C<Devel::SelfStubber> has been upgraded from version 1.03 to 1.05.
1436
1437=item *
1438
5076a392
FC
1439C<diagnostics> has been upgraded from version 1.19 to 1.22.
1440
1441It now renders pod links slightly better, and has been taught to find
1442descriptions for messages that share their descriptions with other
1443messages.
1444
1445=item *
1446
1447C<Digest::MD5> has been upgraded from version 2.39 to 2.51.
1448
1449It is now safe to use this module in combination with threads.
1450
1451=item *
1452
1453C<Digest::SHA> has been upgraded from version 5.47 to 5.61.
1454
1455C<shasum> now more closely mimics C<sha1sum>/C<md5sum>.
1456
1457C<Addfile> accepts all POSIX filenames.
1458
1984204c
FC
1459New SHA-512/224 and SHA-512/256 transforms (ref. NIST Draft FIPS 180-4
1460[February 2011])
5076a392
FC
1461
1462=item *
1463
88410521
FR
1464C<DirHandle> has been upgraded from version 1.03 to 1.04.
1465
1466=item *
1467
e53cbaa3
FR
1468C<Dumpvalue> has been upgraded from version 1.13 to 1.16.
1469
1470=item *
1471
31e8b85a 1472C<DynaLoader> has been upgraded from version 1.10 to 1.13.
5076a392
FC
1473
1474It fixes a buffer overflow when passed a very long file name.
1475
1476It no longer inherits from AutoLoader; hence it no longer
1477produces weird error messages for unsuccessful method calls on classes that
1478inherit from DynaLoader [perl #84358].
1479
1480=item *
1481
1482C<Encode> has been upgraded from version 2.39 to 2.42.
1483
1484Now, all 66 Unicode non-characters are treated the same way U+FFFF has
1984204c
FC
1485always been treated; in cases when it was disallowed, all 66 are
1486disallowed; in those cases where it warned, all 66 warn.
5076a392
FC
1487
1488=item *
1489
68f90ac3
FR
1490C<Env> has been upgraded from version 1.01 to 1.02.
1491
1492=item *
1493
5076a392
FC
1494C<Errno> has been upgraded from version 1.11 to 1.13.
1495
1496The implementation of C<Errno> has been refactored to use about 55% less memory.
5076a392
FC
1497
1498On some platforms with unusual header files, like Win32/gcc using mingw64
1499headers, some constants which weren't actually error numbers have been exposed
1500by C<Errno>. This has been fixed [perl #77416].
1501
1502=item *
1503
1504C<Exporter> has been upgraded from version 5.64_01 to 5.64_03.
1505
1506Exporter no longer overrides C<$SIG{__WARN__}> [perl #74472]
1507
1508=item *
1509
25fe7f8f
FR
1510C<ExtUtils::CBuilder> has been upgraded from version 0.27 to 0.280202.
1511
1512=item *
1513
2292e71e
FR
1514C<ExtUtils::Command> has been upgraded from version 1.16 to 1.17.
1515
1516=item *
1517
5076a392
FC
1518C<ExtUtils::Constant> has been upgraded from 0.22 to 0.23.
1519
1520The C<AUTOLOAD> helper code generated by C<ExtUtils::Constant::ProxySubs>
1521can now C<croak> for missing constants, or generate a complete C<AUTOLOAD>
1984204c
FC
1522subroutine in XS, allowing simplification of many modules that use it
1523(C<Fcntl>, C<File::Glob>, C<GDBM_File>, C<I18N::Langinfo>, C<POSIX>,
1524C<Socket>).
5076a392
FC
1525
1526C<ExtUtils::Constant::ProxySubs> can now optionally push the names of all
1984204c 1527constants onto the package's C<@EXPORT_OK>.
5076a392
FC
1528
1529=item *
1530
588c5853
FR
1531C<ExtUtils::Install> has been upgraded from version 1.55 to 1.56.
1532
1533=item *
1534
5418ffb3
FR
1535C<ExtUtils::MakeMaker> has been upgraded from version 6.56 to 6.57_05.
1536
1537=item *
1538
f40ab45f
FR
1539C<ExtUtils::Manifest> has been upgraded from version 1.57 to 1.58.
1540
1541=item *
1542
10fb15d2 1543C<ExtUtils::ParseXS> has been upgraded from version 2.21 to 2.2210.
b7064dd7
FR
1544
1545=item *
1546
8b87be80 1547C<Fcntl> has been upgraded from version 1.06 to 1.11.
26f7fa64
FR
1548
1549=item *
1550
1551C<File::Basename> has been upgraded from version 2.78 to 2.81.
8b87be80
FR
1552
1553=item *
1554
05102622
FR
1555C<File::CheckTree> has been upgraded from version 4.4 to 4.41.
1556
1557=item *
1558
65d78858
FR
1559C<File::Copy> has been upgraded from version 2.17 to 2.21.
1560
1561=item *
1562
e12786fa 1563C<File::DosGlob> has been upgraded from version 1.01 to 1.04.
5076a392
FC
1564
1565It allows patterns containing literal parentheses (they no longer need to
1984204c
FC
1566be escaped). On Windows, it no longer
1567adds an extra F<./> to the file names
5076a392
FC
1568returned when the pattern is a relative glob with a drive specification,
1569like F<c:*.pl> [perl #71712].
1570
1571=item *
1572
1573C<File::Fetch> has been upgraded from version 0.24 to 0.32.
1574
1575C<HTTP::Lite> is now supported for 'http' scheme.
1576
1577The C<fetch> utility is supported on FreeBSD, NetBSD and
1578Dragonfly BSD for the C<http> and C<ftp> schemes.
1579
1580=item *
1581
23f2cbb1 1582C<File::Find> has been upgraded from version 1.15 to 1.19.
5076a392 1583
1984204c 1584It improves handling of backslashes on Windows, so that paths like
5076a392
FC
1585F<c:\dir\/file> are no longer generated [perl #71710].
1586
1587=item *
1588
0ae9f678
FR
1589C<File::Glob> has been upgraded from version 1.07 to 1.12.
1590
1591=item *
1592
d430b8e7
FC
1593C<File::Spec> has been upgraded from version 3.31 to 3.33.
1594
1595Several portability fixes were made in C<File::Spec::VMS>: a colon is now
1596recognized as a delimiter in native filespecs; caret-escaped delimiters are
1597recognized for better handling of extended filespecs; C<catpath()> returns
1598an empty directory rather than the current directory if the input directory
1599name is empty; C<abs2rel()> properly handles Unix-style input (5.12.2).
1600
1601=item *
1602
46ba0657 1603C<File::stat> has been upgraded from 1.02 to 1.05.
5076a392
FC
1604
1605The C<-x> and C<-X> file test operators now work correctly under the root
1606user.
1607
1608=item *
1609
b7edcc3c
FR
1610C<Filter::Simple> has been upgraded from version 0.84 to 0.86.
1611
1612=item *
1613
dc6857fd 1614C<GDBM_File> has been upgraded from 1.10 to 1.14.
5076a392
FC
1615
1616This fixes a memory leak when DBM filters are used.
1617
1618=item *
1619
6e107b45 1620C<Hash::Util> has been upgraded from 0.07 to 0.11.
5076a392 1621
1984204c
FC
1622Hash::Util no longer emits spurious "uninitialized" warnings when
1623recursively locking hashes that have undefined values [perl #74280].
5076a392
FC
1624
1625=item *
1626
89ce9b34
FR
1627C<Hash::Util::FieldHash> has been upgraded from version 1.04 to 1.09.
1628
1629=item *
1630
eec33fe6
FR
1631C<I18N::Collate> has been upgraded from version 1.01 to 1.02.
1632
1633=item *
1634
ad5f8f47 1635C<I18N::Langinfo> has been upgraded from version 0.03 to 0.08.
5076a392
FC
1636
1637C<langinfo()> now defaults to using C<$_> if there is no argument given, just
5334145a 1638as the documentation has always claimed.
5076a392
FC
1639
1640=item *
1641
c41635f7
FR
1642C<I18N::LangTags> has been upgraded from version 0.35 to 0.35_01.
1643
1644=item *
1645
98a6a4ff
FR
1646C<if> has been upgraded from version 0.05 to 0.0601.
1647
1648=item *
1649
f6ff7fb6
FR
1650C<IO> has been upgraded from version 1.25_02 to 1.25_04.
1651
582bf58c
FR
1652This version of C<IO> includes a new C<IO::Select>, which now allows IO::Handle
1653objects (and objects in derived classes) to be removed from an IO::Select set
1654even if the underlying file descriptor is closed or invalid.
5076a392
FC
1655
1656=item *
1657
d07561d3 1658C<IPC::Cmd> has been upgraded from version 0.54 to 0.70.
5076a392 1659
1984204c
FC
1660Resolves an issue with splitting Win32 command lines. An argument
1661consisting of the single character "0" used to be omitted (CPAN RT #62961).
5076a392
FC
1662
1663=item *
1664
3f16e4eb 1665C<IPC::Open3> has been upgraded from 1.05 to 1.09.
5076a392 1666
4ed2cea4
FC
1667C<open3> now produces an error if the C<exec> call fails, allowing this
1668condition to be distinguished from a child process that exited with a
1669non-zero status [perl #72016].
1670
5076a392
FC
1671The internal C<xclose> routine now knows how to handle file descriptors, as
1672documented, so duplicating STDIN in a child process using its file
1673descriptor now works [perl #76474].
1674
1675=item *
1676
c8b41807
FR
1677C<IPC::SysV> has been upgraded from version 2.01 to 2.03.
1678
1679=item *
1680
ef79f038
FR
1681C<lib> has been upgraded from version 0.62 to 0.63.
1682
1683=item *
1684
5b1884f4 1685C<Locale::Maketext> has been upgraded from version 1.14 to 1.19.
5076a392 1686
1984204c 1687Locale::Maketext now supports external caches.
5076a392 1688
1984204c
FC
1689This upgrade also fixes an infinite loop in
1690C<Locale::Maketext::Guts::_compile()> when
5076a392
FC
1691working with tainted values (CPAN RT #40727).
1692
1984204c 1693C<< ->maketext >> calls will now back up and restore C<$@> so that error
5076a392
FC
1694messages are not suppressed (CPAN RT #34182).
1695
1696=item *
1697
3811bd2b
FR
1698C<Log::Message> has been upgraded from version 0.02 to 0.04.
1699
1700=item *
1701
8eb65377
FR
1702C<Log::Message::Simple> has been upgraded from version 0.06 to 0.08.
1703
1704=item *
1705
5076a392
FC
1706C<Math::BigInt> has been upgraded from version 1.89_01 to 1.994.
1707
1708This fixes, among other things, incorrect results when computing binomial
1709coefficients [perl #77640].
1710
1984204c 1711It also prevents C<sqrt($int)> from crashing under C<use bigrat;>
5076a392
FC
1712[perl #73534].
1713
1714=item *
1715
846c1cec
FR
1716C<Math::BigInt::FastCalc> has been upgraded from version 0.19 to 0.28.
1717
1718=item *
1719
fce4aef3
FR
1720C<Math::BigRat> has been upgraded from version 0.24 to 0.26_02.
1721
1722=item *
1723
12e26027
FR
1724C<Memoize> has been upgraded from version 1.01_03 to 1.02.
1725
1726=item *
1727
5076a392
FC
1728C<MIME::Base64> has been upgraded from 3.08 to 3.13.
1729
1730Includes new functions to calculate the length of encoded and decoded
1731base64 strings.
1732
1733Now provides C<encode_base64url> and C<decode_base64url> functions to process
1734the base64 scheme for "URL applications".
1735
1736=item *
1737
1738C<Module::Build> has been upgraded from version 0.3603 to 0.3800.
1739
1740A notable change is the deprecation of several modules.
1741Module::Build::Version has been deprecated and Module::Build now relies
1742directly upon L<version>. Module::Build::ModuleInfo has been deprecated in
1743favor of a standalone copy of it called L<Module::Metadata>.
1744Module::Build::YAML has been deprecated in favor of L<CPAN::Meta::YAML>.
1745
1746Module::Build now also generates META.json and MYMETA.json files
1747in accordance with version 2 of the CPAN distribution metadata specification,
1748L<CPAN::Meta::Spec>. The older format META.yml and MYMETA.yml files are
1749still generated, as well.
1750
1751=item *
1752
7259fe26 1753C<Module::CoreList> has been upgraded from version 2.29 to 2.47.
5076a392
FC
1754
1755Besides listing the updated core modules of this release, it also stops listing
1984204c 1756the C<Filespec> module. That module never existed in core. The scripts
5076a392 1757generating C<Module::CoreList> confused it with C<VMS::Filespec>, which actually
1984204c 1758is a core module as of perl 5.8.7.
5076a392
FC
1759
1760=item *
1761
193af05b
FR
1762C<Module::Load> has been upgraded from version 0.16 to 0.18.
1763
1764=item *
1765
5b3a054f
FR
1766C<Module::Load::Conditional> has been upgraded from version 0.34 to 0.44.
1767
1768=item *
1769
01835e3a
FR
1770C<mro> has been upgraded from version 1.02 to 1.07.
1771
1772=item *
1773
bfe7bf96 1774C<NDBM_File> has been upgraded from version 1.08 to 1.12.
4f978a3b
FR
1775
1776This fixes a memory leak when DBM filters are used.
1777
1778=item *
1779
d0aa5c91
FR
1780C<Net::Ping> has been upgraded from version 2.36 to 2.38.
1781
1782=item *
1783
d44b8a8c
FR
1784C<NEXT> has been upgraded from version 0.64 to 0.65.
1785
1786=item *
1787
678d4fd4
FR
1788C<Object::Accessor> has been upgraded from version 0.36 to 0.38.
1789
1790=item *
1791
34188656 1792C<ODBM_File> have been upgraded from version 1.07 to 1.10.
5076a392
FC
1793
1794This fixes a memory leak when DBM filters are used.
1795
1796=item *
1797
4c69840c
FR
1798C<Opcode> has been upgraded from version 1.15 to 1.18.
1799
1800=item *
1801
f4c5ae54 1802C<overload> has been upgraded from 1.10 to 1.13.
5076a392
FC
1803
1804C<overload::Method> can now handle subroutines that are themselves blessed
1805into overloaded classes [perl #71998].
1806
5076a392
FC
1807The documentation has greatly improved. See L</Documentation> below.
1808
1809=item *
1810
f84c796e
FR
1811C<Params::Check> has been upgraded from version 0.26 to 0.28.
1812
1813=item *
1814
550ee92b
FR
1815C<parent> has been upgraded from version 0.223 to 0.225.
1816
1817=item *
1818
5076a392
FC
1819C<Parse::CPAN::Meta> has been upgraded from version 1.40 to 1.4401.
1820
1984204c 1821The latest Parse::CPAN::Meta can now read YAML and JSON files using
5076a392
FC
1822L<CPAN::Meta::YAML> and L<JSON::PP>, which are now part of the Perl core.
1823
1824=item *
1825
e981cf86
FR
1826C<PerlIO::encoding> has been upgraded from version 0.12 to 0.14.
1827
1828=item *
1829
5076a392
FC
1830C<PerlIO::scalar> has been upgraded from 0.07 to 0.11.
1831
1832A C<read> after a C<seek> beyond the end of the string no longer thinks it
1833has data to read [perl #78716].
1834
1835=item *
1836
776f733b
FR
1837C<PerlIO::via> has been upgraded from version 0.09 to 0.11.
1838
1839=item *
1840
ae9456cc
FR
1841C<Pod::Html> has been upgraded from version 1.09 to 1.1.
1842
1843=item *
1844
be3c8498
FR
1845C<Pod::LaTeX> has been upgraded from version 0.58 to 0.59.
1846
1847=item *
1848
fd8a2e89
FR
1849C<Pod::Perldoc> has been upgraded from version 3.15_02 to 3.15_03.
1850
1851=item *
1852
5bcb6583
FR
1853C<Pod::Simple> has been upgraded from version 3.13 to 3.16.
1854
1855=item *
1856
abb8c779 1857C<POSIX> has been upgraded from 1.19 to 1.24.
5076a392
FC
1858
1859It now includes constants for POSIX signal constants.
1860
1861=item *
1862
1984204c 1863C<re> has been upgraded from version 0.11 to 0.17.
5076a392
FC
1864
1865New C<use re "/flags"> pragma
1866
5076a392 1867The C<regmust> function used to crash when called on a regular expression
1984204c 1868belonging to a pluggable engine. Now it croaks instead.
5076a392
FC
1869
1870C<regmust> no longer leaks memory.
1871
1872=item *
1873
1874C<Safe> has been upgraded from version 2.25 to 2.29.
1875
cdc10f43
FC
1876Coderefs returned by C<reval()> and C<rdo()> are now wrapped via
1877C<wrap_code_refs> (5.12.1).
1878
5076a392
FC
1879This fixes a possible infinite loop when looking for coderefs.
1880
cdc10f43 1881It adds several version::vxs::* routines to the default share.
5076a392
FC
1882
1883=item *
1884
2c19fa42
FR
1885C<SDBM_File> has been upgraded from version 1.06 to 1.09.
1886
1887=item *
1888
5076a392
FC
1889C<SelfLoader> has been upgraded from 1.17 to 1.18.
1890
1891It now works in taint mode [perl #72062].
1892
1893=item *
1894
1895C<sigtrap> has been upgraded from version 1.04 to 1.05.
1896
1897It no longer tries to modify read-only arguments when generating a
1898backtrace [perl #72340].
1899
1900=item *
1901
1984204c 1902C<Socket> has been upgraded from version 1.87 to 1.94.
5076a392 1903
1984204c 1904See L</IPv6 support>, above.
5076a392
FC
1905
1906=item *
1907
1908C<Storable> has been upgraded from version 2.22 to 2.27.
1909
1910Includes performance improvement for overloaded classes.
1911
5076a392 1912This adds support for serialising code references that contain UTF-8 strings
1984204c
FC
1913correctly. The Storable minor version
1914number changed as a result, meaning that
5076a392
FC
1915Storable users who set C<$Storable::accept_future_minor> to a C<FALSE> value
1916will see errors (see L<Storable/FORWARD COMPATIBILITY> for more details).
1917
1918Freezing no longer gets confused if the Perl stack gets reallocated
1919during freezing [perl #80074].
1920
1921=item *
1922
648c3d7d
FR
1923C<Sys::Hostname> has been upgraded from version 1.11 to 1.16.
1924
1925=item *
1926
90c6e78f
FR
1927C<Term::ANSIColor> has been upgraded from version 2.02 to 3.00.
1928
1929=item *
1930
d9f2f059
FR
1931C<Term::UI> has been upgraded from version 0.20 to 0.26.
1932
1933=item *
1934
80ebb519
FR
1935C<Test::Harness> has been upgraded from version 3.17 to 3.23.
1936
1937=item *
1938
5076a392
FC
1939C<Test::Simple> has been upgraded from version 0.94 to 0.98.
1940
1941Among many other things, subtests without a C<plan> or C<no_plan> now have an
1942implicit C<done_testing()> added to them.
1943
1944=item *
1945
5076a392
FC
1946C<Thread::Semaphore> has been upgraded from version 2.09 to 2.12.
1947
1984204c
FC
1948It provides two new methods that give more control over the decrementing of
1949semaphores: C<down_nb> and C<down_force>.
5076a392
FC
1950
1951=item *
1952
f0d895e1
FR
1953C<Thread::Queue> has been upgraded from version 2.11 to 2.12.
1954
1955=item *
1956
1a6b954e
FR
1957C<threads> has been upgraded from version 1.75 to 1.83.
1958
1959=item *
1960
55816daa
FR
1961C<threads::shared> has been upgraded from version 1.32 to 1.36.
1962
1963=item *
1964
5076a392
FC
1965C<Tie::Hash> has been upgraded from version 1.03 to 1.04.
1966
1967Calling C<< Tie::Hash-E<gt>TIEHASH() >> used to loop forever. Now it C<croak>s.
1968
1969=item *
1970
f2adc546
FR
1971C<Tie::Hash::NamedCapture> has been upgraded from version 0.06 to 0.08.
1972
1973=item *
1974
ed68b07e
FR
1975C<Tie::RefHash> has been upgraded from version 1.38 to 1.39.
1976
1977=item *
1978
bb3c221a
FR
1979C<Time::HiRes> has been upgraded from version 1.9719 to 1.9721_01.
1980
1981=item *
1982
97fa568b
FR
1983C<Time::Local> has been upgraded from version 1.1901_01 to 1.2000.
1984
1985=item *
1986
a83cb732
FR
1987C<Time::Piece> has been upgraded from version 1.15_01 to 1.20_01.
1988
1989=item *
1990
5076a392
FC
1991C<Unicode::Collate> has been upgraded from version 0.52_01 to 0.73.
1992
1984204c 1993Unicode::Collate has been updated to use Unicode 6.0.0.
5076a392 1994
1984204c
FC
1995Unicode::Collate::Locale now supports a plethora of new locales: ar, be,
1996bg, de__phonebook, hu, hy, kk, mk, nso, om, tn, vi, hr, ig, ja, ko, ru, sq,
1997se, sr, to, uk, zh, zh__big5han, zh__gb2312han, zh__pinyin and zh__stroke.
5076a392
FC
1998
1999The following modules have been added:
2000
2001C<Unicode::Collate::CJK::Big5> for C<zh__big5han> which makes
2002tailoring of CJK Unified Ideographs in the order of CLDR's big5han ordering.
2003
2004C<Unicode::Collate::CJK::GB2312> for C<zh__gb2312han> which makes
2005tailoring of CJK Unified Ideographs in the order of CLDR's gb2312han ordering.
2006
2007C<Unicode::Collate::CJK::JISX0208> which makes tailoring of 6355 kanji
2008(CJK Unified Ideographs) in the JIS X 0208 order.
2009
2010C<Unicode::Collate::CJK::Korean> which makes tailoring of CJK Unified Ideographs
2011in the order of CLDR's Korean ordering.
2012
2013C<Unicode::Collate::CJK::Pinyin> for C<zh__pinyin> which makes
2014tailoring of CJK Unified Ideographs in the order of CLDR's pinyin ordering.
2015
2016C<Unicode::Collate::CJK::Stroke> for C<zh__stroke> which makes
2017tailoring of CJK Unified Ideographs in the order of CLDR's stroke ordering.
2018
5076a392
FC
2019This also sees the switch from using the pure-perl version of this
2020module to the XS version.
2021
2022=item *
2023
ec52b54b
FR
2024C<Unicode::Normalize> has been upgraded from version 1.03 to 1.10.
2025
2026=item *
2027
5076a392
FC
2028C<Unicode::UCD> has been upgraded from version 0.27 to 0.32.
2029
1984204c
FC
2030A new function, C<Unicode::UCD::num()>, has been added. This function
2031returns the numeric value of the string passed it or C<undef> if the string
2032in its entirety has no "safe" numeric value. (For more detail, and for the
2033definition of "safe", see L<Unicode::UCD/num>.)
5076a392 2034
1984204c 2035This upgrade also includes a number of bug fixes:
5076a392
FC
2036
2037=over 4
2038
2039=item charinfo()
2040
2041=over 4
2042
2043=item *
2044
2045It is now updated to Unicode Version 6 with Corrigendum #8, except,
2046as with Perl 5.14, the code point at U+1F514 has no name.
2047
2048=item *
2049
2050The Hangul syllable code points have the correct names, and their
2051decompositions are always output without requiring L<Lingua::KO::Hangul::Util>
2052to be installed.
2053
2054=item *
2055
54c7bb16
FC
2056The CJK (Chinese-Japanese-Korean) code points U+2A700 to U+2B734
2057and U+2B740 to U+2B81D are now properly handled.
5076a392
FC
2058
2059=item *
2060
2061The numeric values are now output for those CJK code points that have them.
2062
2063=item *
2064
2065The names that are output for code points with multiple aliases are now the
2066corrected ones.
2067
2068=back
2069
2070=item charscript()
2071
2072This now correctly returns "Unknown" instead of C<undef> for the script
2073of a code point that hasn't been assigned another one.
2074
2075=item charblock()
2076
2077This now correctly returns "No_Block" instead of C<undef> for the block
2078of a code point that hasn't been assigned to another one.
2079
2080=back
2081
5076a392
FC
2082=item *
2083
2084C<version> has been upgraded from 0.82 to 0.88.
2085
1984204c 2086Due to a bug, now fixed, the C<is_strict> and C<is_lax> functions did not
cdc10f43 2087work when exported (5.12.1).
5076a392
FC
2088
2089=item *
2090
3e625598 2091C<warnings> has been upgraded from version 1.09 to 1.12.
5076a392
FC
2092
2093Calling C<use warnings> without arguments is now significantly more efficient.
2094
4f978a3b
FR
2095=item *
2096
2097C<warnings::register> have been upgraded from version 1.01 to 1.02.
2098
5076a392
FC
2099It is now possible to register warning categories other than the names of
2100packages using C<warnings::register>. See L<perllexwarn> for more information.
2101
2102=item *
2103
62e270c2
FR
2104C<XSLoader> has been upgraded from version 0.10 to 0.13.
2105
2106=item *
2107
5076a392
FC
2108C<VMS::DCLsym> has been upgraded from version 1.03 to 1.05.
2109
2110Two bugs have been fixed [perl #84086]:
2111
2112The symbol table name was lost when tying a hash, due to a thinko in
2113C<TIEHASH>. The result was that all tied hashes interacted with the
2114local symbol table.
2115
2116Unless a symbol table name had been explicitly specified in the call
2117to the constructor, querying the special key ':LOCAL' failed to
2118identify objects connected to the local symbol table.
2119
2120=item *
2121
2122C<Win32> has been upgraded from version 0.39 to 0.44.
2123
1984204c
FC
2124This release has several new functions: C<Win32::GetSystemMetrics>,
2125C<Win32::GetProductInfo>, C<Win32::GetOSDisplayName>.
5076a392 2126
1984204c
FC
2127The names returned by C<Win32::GetOSName> and C<Win32::GetOSDisplayName>
2128have been corrected.
5076a392 2129
3bbe5383
FR
2130=item *
2131
2132C<XS::Typemap> has been upgraded from version 0.03 to 0.05.
2133
5076a392
FC
2134=back
2135
5076a392
FC
2136=head2 Removed Modules and Pragmata
2137
2138The following modules have been removed from the core distribution, and if
2139needed should be installed from CPAN instead.
2140
2141=over
2142
4f978a3b
FR
2143=item *
2144
2145C<Class::ISA> has been removed from the Perl core. Prior version was 0.36.
5076a392 2146
4f978a3b
FR
2147=item *
2148
2149C<Pod::Plainer> has been removed from the Perl core. Prior version was 1.02.
2150
2151=item *
5076a392 2152
4f978a3b 2153C<Switch> has been removed from the Perl core. Prior version was 2.16.
5076a392
FC
2154
2155=back
2156
2157The removal of C<Shell> has been deferred until after 5.14, as the
2158implementation of C<Shell> shipped with 5.12.0 did not correctly issue the
2159warning that it was to be removed from core.
2160
2161=head1 Documentation
2162
5076a392
FC
2163=head2 New Documentation
2164
41e29def 2165=head3 L<perlgpl>
5076a392
FC
2166
2167L<perlgpl> has been updated to contain GPL version 1, as is included in the
cdc10f43 2168F<README> distributed with perl (5.12.1).
5076a392 2169
41e29def 2170=head3 Perl 5.12.x delta files
5076a392 2171
41e29def
FC
2172The perldelta files for Perl 5.12.1 to 5.12.3 have been added from the
2173maintenance branch: L<perl5121delta>, L<perl5122delta>, L<perl5123delta>.
5076a392
FC
2174
2175=head3 L<perlpodstyle>
2176
2177New style guide for POD documentation,
2178split mostly from the NOTES section of the pod2man man page.
2179
41e29def
FC
2180=head3 L<perlsource>, L<perlinterp>, L<perlhacktut>, and L<perlhacktips>
2181
cc13eef1 2182See L</perlhack and perlrepository revamp>, below.
5076a392
FC
2183
2184=head2 Changes to Existing Documentation
2185
41e29def 2186=head3 L<perlmodlib> is now complete
4ed2cea4
FC
2187
2188The perlmodlib page that came with Perl 5.12.0 was missing a lot of
a60ea503 2189modules, due to a bug in the script that generates the list. This has been
cdc10f43 2190fixed [perl #74332] (5.12.1).
4ed2cea4 2191
41e29def 2192=head3 Replace wrong tr/// table in L<perlebcdic>
5076a392 2193
41e29def 2194L<perlebcdic> contains a helpful table to use in tr/// to convert
5076a392
FC
2195between EBCDIC and Latin1/ASCII. Unfortunately, the table was the
2196inverse of the one it describes, though the code that used the table
2197worked correctly for the specific example given.
2198
2199The table has been changed to its inverse, and the sample code changed
2200to correspond, as this is easier for the person trying to follow the
2201instructions since deriving the old table is somewhat more complicated.
2202
2203The table has also been changed to hex from octal, as that is more the norm
2204these days, and the recipes in the pod altered to print out leading
41e29def 2205zeros to make all the values the same length.
5076a392 2206
41e29def 2207=head3 Tricks for user-defined casing
5076a392 2208
41e29def
FC
2209L<perlunicode> now contains an explanation of how to override, mangle
2210and otherwise tweak the way perl handles upper-, lower- and other-case
2211conversions on Unicode data, and how to provide scoped changes to alter
2212one's own code's behaviour without stomping on anybody else.
5076a392
FC
2213
2214=head3 INSTALL explicitly states the requirement for C89
2215
d430b8e7
FC
2216This was already true but it's now Officially Stated For The Record
2217(5.12.2).
5076a392 2218
41e29def 2219=head3 Explanation of C<\xI<HH>> and C<\oI<OOO>> escapes
5076a392 2220
41e29def
FC
2221L<perlop> has been updated with more detailed explanation of these two
2222character escapes.
5076a392 2223
41e29def 2224=head3 C<-0I<NNN>> switch
5076a392 2225
41e29def 2226In L<perlrun>, the behavior of the C<-0NNN> switch for C<-0400> or higher
d430b8e7 2227has been clarified (5.12.2).
5076a392 2228
cdc10f43
FC
2229=head3 Maintenance policy
2230
2231L<perlpolicy> now contains the policy on what patches are acceptable for
2232maintenance branches (5.12.1).
2233
41e29def 2234=head3 Deprecation policy
5076a392 2235
41e29def 2236L<perlpolicy> now contains the policy on compatibility and deprecation
d430b8e7 2237along with definitions of terms like "deprecation" (5.12.2).
5076a392 2238
41e29def 2239=head3 New descriptions in L<perldiag>
5076a392
FC
2240
2241The following existing diagnostics are now documented:
2242
2243=over 4
2244
2245=item *
2246
2247L<Ambiguous use of %c resolved as operator %c|perldiag/"Ambiguous use of %c resolved as operator %c">
2248
2249=item *
2250
2251L<Ambiguous use of %c{%s} resolved to %c%s|perldiag/"Ambiguous use of %c{%s} resolved to %c%s">
2252
2253=item *
2254
2255L<Ambiguous use of %c{%s%s} resolved to %c%s%s|perldiag/"Ambiguous use of %c{%s%s} resolved to %c%s%s">
2256
2257=item *
2258
2259L<Ambiguous use of -%s resolved as -&%s()|perldiag/"Ambiguous use of -%s resolved as -&%s()">
2260
2261=item *
2262
2263L<Invalid strict version format (%s)|perldiag/"Invalid strict version format (%s)">
2264
2265=item *
2266
2267L<Invalid version format (%s)|perldiag/"Invalid version format (%s)">
2268
2269=item *
2270
2271L<Invalid version object|perldiag/"Invalid version object">
2272
2273=back
2274
5076a392
FC
2275=head3 L<perlbook>
2276
41e29def 2277L<perlbook> has been expanded to cover many more popular books.
5076a392 2278
41e29def 2279=head3 C<SvTRUE> macro
5076a392 2280
41e29def
FC
2281The documentation for the C<SvTRUE> macro in
2282L<perlapi> was simply wrong in stating that
a60ea503 2283get-magic is not processed. It has been corrected.
5076a392 2284
41e29def 2285=head3 L<perlvar> revamp
5076a392 2286
41e29def 2287L<perlvar> reorders the variables and groups them by topic. Each variable
5076a392 2288introduced after Perl 5.000 notes the first version in which it is
41e29def 2289available. L<perlvar> also has a new section for deprecated variables to
5076a392
FC
2290note when they were removed.
2291
41e29def 2292=head3 Array and hash slices in scalar context
5076a392 2293
41e29def 2294These are now documented in L<perldata>.
5076a392 2295
41e29def 2296=head3 C<use locale> and formats
5076a392
FC
2297
2298L<perlform> and L<perllocale> have been corrected to state that
2299C<use locale> affects formats.
2300
5076a392
FC
2301=head3 L<overload>
2302
a60ea503 2303L<overload>'s documentation has practically undergone a rewrite. It
5076a392
FC
2304is now much more straightforward and clear.
2305
cc13eef1 2306=head3 perlhack and perlrepository revamp
5076a392
FC
2307
2308The L<perlhack> and perlrepository documents have been heavily edited and
2309split up into several new documents.
2310
2311The L<perlhack> document is now much shorter, and focuses on the Perl 5
a60ea503
FC
2312development process and submitting patches
2313to Perl. The technical content has
5076a392 2314been moved to several new documents, L<perlsource>, L<perlinterp>,
a60ea503 2315L<perlhacktut>, and L<perlhacktips>. This technical content has only been
5076a392
FC
2316lightly edited.
2317
a60ea503
FC
2318The perlrepository document has been renamed to
2319L<perlgit>. This new document is just a how-to
2320on using git with the Perl source code. Any other content
5076a392
FC
2321that used to be in perlrepository has been moved to perlhack.
2322
41e29def 2323=head3 Time::Piece examples
5076a392
FC
2324
2325Examples in L<perlfaq4> have been updated to show the use of
41e29def 2326L<Time::Piece>.
5076a392
FC
2327
2328=head1 Diagnostics
2329
2330The following additions or changes have been made to diagnostic output,
2331including warnings and fatal error messages. For the complete list of
2332diagnostic messages, see L<perldiag>.
2333
2334=head2 New Diagnostics
2335
a593b319
FC
2336=head3 New Errors
2337
5076a392
FC
2338=over
2339
a593b319 2340=item Closure prototype called
5076a392 2341
a593b319
FC
2342This error occurs when a subroutine reference passed to an attribute
2343handler is called, if the subroutine is a closure [perl #68560].
5076a392 2344
a593b319 2345=item Insecure user-defined property %s
5076a392 2346
a593b319
FC
2347Perl detected tainted data when trying to compile a regular
2348expression that contains a call to a user-defined character property
2349function, i.e. C<\p{IsFoo}> or C<\p{InFoo}>.
2350See L<perlunicode/User-Defined Character Properties> and L<perlsec>.
5076a392 2351
a593b319 2352=item panic: gp_free failed to free glob pointer - something is repeatedly re-creating entries
5076a392 2353
a593b319
FC
2354This new error is triggered if a destructor called on an object in a
2355typeglob that is being freed creates a new typeglob entry containing an
2356object with a destructor that creates a new entry containing an object....
5076a392 2357
a593b319 2358=item Parsing code internal error (%s)
5076a392 2359
a593b319
FC
2360This new fatal error is produced when parsing
2361code supplied by an extension violates the
2362parser's API in a detectable way.
5076a392 2363
a593b319 2364=item refcnt: fd %d%s
5076a392 2365
a593b319
FC
2366This new error only occurs if a internal consistency check fails when a
2367pipe is about to be closed.
5076a392 2368
a593b319 2369=item Regexp modifier "/%c" may not appear twice
5076a392 2370
a593b319
FC
2371The regular expression pattern has one of the
2372mutually exclusive modifiers repeated.
5076a392 2373
a593b319 2374=item Regexp modifiers "/%c" and "/%c" are mutually exclusive
5076a392 2375
a593b319
FC
2376The regular expression pattern has more than one of the mutually
2377exclusive modifiers.
5076a392 2378
a593b319 2379=item Using !~ with %s doesn't make sense
5076a392 2380
a593b319 2381This error occurs when C<!~> is used with C<s///r> or C<y///r>.
5076a392 2382
a593b319 2383=back
5076a392 2384
a593b319 2385=head3 New Warnings
5076a392 2386
a593b319 2387=over
5076a392 2388
a593b319 2389=item "\b{" is deprecated; use "\b\{" instead
5076a392 2390
a593b319 2391=item "\B{" is deprecated; use "\B\{" instead
5076a392 2392
a593b319
FC
2393Use of an unescaped "{" immediately following a C<\b> or C<\B> is now
2394deprecated so as to reserve its use for Perl itself in a future release.
5076a392 2395
a593b319 2396=item Operation "%s" returns its argument for ...
5076a392 2397
a593b319 2398Performing an operation requiring Unicode semantics (such as case-folding)
a60ea503
FC
2399on a Unicode surrogate or a non-Unicode character now triggers this
2400warning.
5076a392 2401
a593b319
FC
2402=item Use of qw(...) as parentheses is deprecated
2403
2404See L</"Use of qw(...) as parentheses">, above, for details.
5076a392
FC
2405
2406=back
2407
2408=head2 Changes to Existing Diagnostics
2409
2410=over 4
2411
2412=item *
2413
4ed2cea4
FC
2414The "Variable $foo is not imported" warning that precedes a
2415C<strict 'vars'> error has now been assigned the "misc" category, so that
2416C<no warnings> will suppress it [perl #73712].
2417
2418=item *
2419
5076a392
FC
2420C<warn> and C<die> now produce 'Wide character' warnings when fed a
2421character outside the byte range if STDERR is a byte-sized handle.
2422
2423=item *
2424
2425The 'Layer does not match this perl' error message has been replaced with
a593b319 2426these more helpful messages [perl #73754]:
5076a392
FC
2427
2428=over 4
2429
2430=item *
2431
2432PerlIO layer function table size (%d) does not match size expected by this
2433perl (%d)
2434
2435=item *
2436
2437PerlIO layer instance size (%d) does not match size expected by this perl
2438(%d)
2439
2440=back
2441
5076a392
FC
2442=item *
2443
2444The "Found = in conditional" warning that is emitted when a constant is
2445assigned to a variable in a condition is now withheld if the constant is
2446actually a subroutine or one generated by C<use constant>, since the value
2447of the constant may not be known at the time the program is written
2448[perl #77762].
2449
2450=item *
2451
2452Previously, if none of the C<gethostbyaddr>, C<gethostbyname> and
2453C<gethostent> functions were implemented on a given platform, they would
2454all die with the message 'Unsupported socket function "gethostent" called',
2455with analogous messages for C<getnet*> and C<getserv*>. This has been
2456corrected.
2457
2458=item *
2459
a593b319
FC
2460The warning message about unrecognized regular expression escapes passed
2461through has been changed to include any literal '{' following the
2462two-character escape. E.g., "\q{" is now emitted instead of "\q".
5076a392
FC
2463
2464=back
2465
2466=head1 Utility Changes
2467
0b88cc74 2468=head3 L<perlbug>
5076a392
FC
2469
2470=over 4
2471
2472=item *
2473
0b88cc74
FC
2474L<perlbug> now looks in the EMAIL environment variable for a return address
2475if the REPLY-TO and REPLYTO variables are empty.
5076a392
FC
2476
2477=item *
2478
0b88cc74
FC
2479L<perlbug> did not previously generate a From: header, potentially
2480resulting in dropped mail. Now it does include that header.
5076a392
FC
2481
2482=item *
2483
0b88cc74 2484The user's address is now used as the return-path.
4ed2cea4 2485
0b88cc74
FC
2486Many systems these days don't have a valid Internet domain name and
2487perlbug@perl.org does not accept email with a return-path that does
2488not resolve. So the user's address is now passed to sendmail so it's
2489less likely to get stuck in a mail queue somewhere [perl #82996].
5076a392 2490
2c389f6c
FC
2491=item *
2492
d430b8e7
FC
2493L<perlbug> now always gives the reporter a chance to change the email
2494address it guesses for them (5.12.2).
2495
2496=item *
2497
2498L<perlbug> should no longer warn about uninitialized values when using the C<-d>
2499and C<-v> options (5.12.2).
2c389f6c 2500
5076a392
FC
2501=back
2502
0b88cc74 2503=head3 L<perl5db.pl>
5076a392 2504
0b88cc74 2505=over
5076a392
FC
2506
2507=item *
2508
0b88cc74
FC
2509The remote terminal works after forking and spawns new sessions - one
2510for each forked process.
5076a392
FC
2511
2512=back
2513
0b88cc74 2514=head3 L<ptargrep>
5076a392
FC
2515
2516=over 4
2517
2518=item *
2519
0b88cc74
FC
2520L<ptargrep> is a new utility to apply pattern matching to the contents of
2521files in a tar archive. It comes with C<Archive::Tar>.
5076a392
FC
2522
2523=back
2524
2525=head1 Configuration and Compilation
2526
61752d82
FC
2527See also L</"Naming fixes in Policy_sh.SH may invalidate Policy.sh">,
2528above.
2529
5076a392
FC
2530=over 4
2531
2532=item *
2533
87595b22
FC
2534CCINCDIR and CCLIBDIR for the mingw64
2535cross-compiler are now correctly under
5076a392
FC
2536$(CCHOME)\mingw\include and \lib rather than immediately below $(CCHOME).
2537
5076a392
FC
2538This means the 'incpath', 'libpth', 'ldflags', 'lddlflags' and
2539'ldflags_nolargefiles' values in Config.pm and Config_heavy.pl are now
87595b22 2540set correctly.
5076a392
FC
2541
2542=item *
2543
87595b22
FC
2544'make test.valgrind' has been adjusted to account for cpan/dist/ext
2545separation.
5076a392
FC
2546
2547=item *
2548
2549On compilers that support it, C<-Wwrite-strings> is now added to cflags by
2550default.
2551
2552=item *
2553
2554The C<Encode> module can now (once again) be included in a static Perl
2555build. The special-case handling for this situation got broken in Perl
25565.11.0, and has now been repaired.
2557
1e463951
FC
2558=item *
2559
2560The previous default size of a PerlIO buffer (4096 bytes) has been increased
2561to the larger of 8192 bytes and your local BUFSIZ. Benchmarks show that doubling
2562this decade-old default increases read and write performance in the neighborhood
2563of 25% to 50% when using the default layers of perlio on top of unix. To choose
2564a non-default size, such as to get back the old value or to obtain an even
2565larger value, configure with:
2566
2567 ./Configure -Accflags=-DPERLIOBUF_DEFAULT_BUFSIZ=N
2568
2569where N is the desired size in bytes; it should probably be a multiple of
2570your page size.
2571
d430b8e7
FC
2572=item *
2573
2574An "incompatible operand types" error in ternary expressions when building
2575with C<clang> has been fixed (5.12.2).
2576
2577=item *
2578
2579Perl now skips setuid C<File::Copy> tests on partitions it detects to be mounted
2580as C<nosuid> (5.12.2).
2581
5076a392
FC
2582=back
2583
5076a392
FC
2584=head1 Platform Support
2585
5076a392
FC
2586=head2 New Platforms
2587
5076a392
FC
2588=over 4
2589
2590=item AIX
2591
cdc10f43 2592Perl now builds on AIX 4.2 (5.12.1).
5076a392
FC
2593
2594=back
2595
2596=head2 Discontinued Platforms
2597
2598=over 4
2599
5076a392
FC
2600=item Apollo DomainOS
2601
2602The last vestiges of support for this platform have been excised from the
a60ea503
FC
2603Perl distribution. It was officially discontinued
2604in version 5.12.0. It had
5076a392
FC
2605not worked for years before that.
2606
2607=item MacOS Classic
2608
2609The last vestiges of support for this platform have been excised from the
a60ea503 2610Perl distribution. It was officially discontinued in an earlier version.
5076a392
FC
2611
2612=back
2613
2614=head2 Platform-Specific Notes
2615
d430b8e7
FC
2616=head3 AIX
2617
2618=over
2619
2620=item *
2621
2622F<README.aix> has been updated with information about the XL C/C++ V11 compiler
2623suite (5.12.2).
2624
2625=back
2626
2627=head3 ARM
2628
2629=over
2630
2631=item *
2632
2633The C<d_u32align> configuration probe on ARM has been fixed (5.12.2).
2634
2635=back
2636
554003a2 2637=head3 Cygwin
5076a392
FC
2638
2639=over 4
2640
2641=item *
2642
554003a2 2643MakeMaker has been updated to build man pages on cygwin.
5076a392
FC
2644
2645=item *
2646
554003a2
FC
2647Improved rebase behaviour
2648
2649If a dll is updated on cygwin the old imagebase address is reused.
2650This solves most rebase errors, especially when updating on core dll's.
2651See L<http://www.tishler.net/jason/software/rebase/rebase-2.4.2.README> for more information.
5076a392
FC
2652
2653=item *
2654
554003a2 2655Support for the standard cygwin dll prefix, which is e.g. needed for FFI's
5076a392
FC
2656
2657=item *
2658
554003a2 2659Updated build hints file
5076a392
FC
2660
2661=back
2662
cdc10f43
FC
2663=head3 FreeBSD 7
2664
2665=over
2666
2667=item *
2668
2669FreeBSD 7 no longer contains F</usr/bin/objformat>. At build time,
2670Perl now skips the F<objformat> check for versions 7 and higher and
2671assumes ELF (5.12.1).
2672
2673=back
2674
2675=head3 HP-UX
2676
2677=over
2678
2679=item *
2680
2681Perl now allows -Duse64bitint without promoting to use64bitall on HP-UX
2682(5.12.1).
2683
2684=back
2685
554003a2 2686=head3 IRIX
5076a392 2687
a60ea503
FC
2688=over
2689
2690=item *
2691
5076a392
FC
2692Conversion of strings to floating-point numbers is now more accurate on
2693IRIX systems [perl #32380].
2694
a60ea503
FC
2695=back
2696
554003a2 2697=head3 Mac OS X
5076a392 2698
a60ea503
FC
2699=over
2700
2701=item *
2702
5076a392
FC
2703Early versions of Mac OS X (Darwin) had buggy implementations of the
2704C<setregid>, C<setreuid>, C<setrgid> and C<setruid> functions, so perl
2705would pretend they did not exist.
2706
2707These functions are now recognised on Mac OS 10.5 (Leopard; Darwin 9) and
2708higher, as they have been fixed [perl #72990].
2709
a60ea503
FC
2710=back
2711
554003a2 2712=head3 MirBSD
5076a392 2713
a60ea503
FC
2714=over
2715
2716=item *
2717
554003a2
FC
2718Previously if you built perl with a shared libperl.so on MirBSD (the
2719default config), it would work up to the installation; however, once
2720installed, it would be unable to find libperl. So path handling is now
2721treated as in the other BSD dialects.
5076a392 2722
a60ea503
FC
2723=back
2724
554003a2 2725=head3 NetBSD
5076a392 2726
a60ea503
FC
2727=over
2728
2729=item *
2730
554003a2
FC
2731The NetBSD hints file has been changed to make the system's malloc the
2732default.
5076a392 2733
a60ea503
FC
2734=back
2735
554003a2 2736=head3 Recent OpenBSDs now use perl's malloc
5076a392 2737
a60ea503
FC
2738=over
2739
2740=item *
2741
554003a2
FC
2742OpenBSD E<gt> 3.7 has a new malloc implementation which is mmap-based
2743and as such can release memory back to the OS; however, perl's use of
2744this malloc causes a substantial slowdown so we now default to using
2745perl's malloc instead [perl #75742].
5076a392 2746
a60ea503
FC
2747=back
2748
554003a2 2749=head3 OpenVOS
5076a392 2750
a60ea503
FC
2751=over
2752
2753=item *
2754
554003a2 2755perl now builds again with OpenVOS (formerly known as Stratus VOS)
5a553547 2756[perl #78132] (5.12.3).
5076a392 2757
a60ea503
FC
2758=back
2759
554003a2 2760=head3 Solaris
5076a392 2761
a60ea503
FC
2762=over
2763
2764=item *
2765
2766DTrace is now supported on Solaris. There used to be build failures, but
5a553547 2767these have been fixed [perl #73630] (5.12.3).
5076a392 2768
a60ea503
FC
2769=back
2770
554003a2 2771=head3 VMS
5076a392
FC
2772
2773=over
2774
2775=item *
2776
cdc10f43
FC
2777It's now possible to build extensions on older (pre 7.3-2) VMS systems.
2778
2779DCL symbol length was limited to 1K up until about seven years or
2780so ago, but there was no particularly deep reason to prevent those
2781older systems from configuring and building Perl (5.12.1).
2782
2783=item *
2784
2785We fixed the previously-broken C<-Uuseperlio> build on VMS.
2786
2787We were checking a variable that doesn't exist in the non-default
2788case of disabling perlio. Now we only look at it when it exists (5.12.1).
2789
2790=item *
2791
2792We fixed the -Uuseperlio command-line option in configure.com.
2793
2794Formerly it only worked if you went through all the questions
2795interactively and explicitly answered no (5.12.1).
2796
2797=item *
2798
554003a2 2799C<PerlIOUnix_open> now honours the default permissions on VMS.
5076a392 2800
554003a2
FC
2801When C<perlio> became the default and C<unixio> became the default bottom layer,
2802the most common path for creating files from Perl became C<PerlIOUnix_open>,
2803which has always explicitly used C<0666> as the permission mask.
5076a392 2804
554003a2
FC
2805To avoid this, C<0777> is now passed as the permissions to C<open()>. In the
2806VMS CRTL, C<0777> has a special meaning over and above intersecting with the
2807current umask; specifically, it allows Unix syscalls to preserve native default
5a553547
FC
2808permissions (5.12.3).
2809
2810=item *
2811
2812Spurious record boundaries are no longer
2813introduced by the PerlIO layer during output (5.12.3).
5076a392
FC
2814
2815=item *
2816
554003a2
FC
2817The shortening of symbols longer than 31 characters in the C sources is
2818now done by the compiler rather than by xsubpp (which could only do so
2819for generated symbols in XS code).
5076a392
FC
2820
2821=item *
2822
554003a2
FC
2823Record-oriented files (record format variable or variable with fixed control)
2824opened for write by the perlio layer will now be line-buffered to prevent the
2825introduction of spurious line breaks whenever the perlio buffer fills up.
5076a392 2826
d430b8e7
FC
2827=item *
2828
a60ea503
FC
2829F<git_version.h> is now installed on VMS. This
2830was an oversight in v5.12.0 which
d430b8e7
FC
2831caused some extensions to fail to build (5.12.2).
2832
2833=item *
2834
2835Several memory leaks in L<stat()|perlfunc/"stat FILEHANDLE"> have been fixed (5.12.2).
2836
2837=item *
2838
2839A memory leak in C<Perl_rename()> due to a double allocation has been
2840fixed (5.12.2).
2841
2842=item *
2843
2844A memory leak in C<vms_fid_to_name()> (used by C<realpath()> and
2845C<realname()>) has been fixed (5.12.2).
2846
5076a392
FC
2847=back
2848
554003a2 2849=head3 Windows
5076a392 2850
5a1f7719
FC
2851See also L</"fork() emulation will not wait for signalled children"> and
2852L</"Perl source code is read in text mode on Windows">, above.
2853
5076a392
FC
2854=over 4
2855
2856=item *
2857
554003a2 2858Fixed build process for SDK2003SP1 compilers.
5076a392 2859
554003a2 2860=item *
5076a392 2861
01b1a9e4
FC
2862Compilation with Visual Studio 2010 is now supported.
2863
2864=item *
2865
554003a2
FC
2866When using old 32-bit compilers, the define C<_USE_32BIT_TIME_T> will now
2867be set in C<$Config{ccflags}>. This improves portability when compiling
2868XS extensions using new compilers, but for a perl compiled with old 32-bit
2869compilers.
5076a392
FC
2870
2871=item *
2872
554003a2
FC
2873C<$Config{gccversion}> is now set correctly when perl is built using the
2874mingw64 compiler from L<http://mingw64.org> [perl #73754].
5076a392 2875
554003a2
FC
2876=item *
2877
d430b8e7
FC
2878When building Perl with the mingw64 x64 cross-compiler C<incpath>,
2879C<libpth>, C<ldflags>, C<lddlflags> and C<ldflags_nolargefiles> values
2880in F<Config.pm> and F<Config_heavy.pl> were not previously being set
2881correctly because, with that compiler, the include and lib directories
2882are not immediately below C<$(CCHOME)> (5.12.2).
2883
2884=item *
2885
554003a2
FC
2886The build process proceeds more smoothly with mingw and dmake when
2887F<C:\MSYS\bin> is in the PATH, due to a C<Cwd> fix.
5076a392
FC
2888
2889=item *
2890
554003a2
FC
2891Support for building with Visual C++ 2010 is now underway, but is not yet
2892complete. See F<README.win32> or L<perlwin32> for more details.
5076a392 2893
554003a2
FC
2894=item *
2895
2896The option to use an externally-supplied C<crypt()>, or to build with no
2897C<crypt()> at all, has been removed. Perl supplies its own C<crypt()>
2898implementation for Windows, and the political situation that required
2899this part of the distribution to sometimes be omitted is long gone.
5076a392
FC
2900
2901=back
2902
2903=head1 Internal Changes
2904
1e463951 2905=head2 New APIs
5076a392 2906
1e463951 2907=head3 CLONE_PARAMS structure added to ease correct thread creation
5076a392 2908
1e463951
FC
2909Modules that create threads should now create C<CLONE_PARAMS> structures
2910by calling the new function C<Perl_clone_params_new()>, and free them with
2911C<Perl_clone_params_del()>. This will ensure compatibility with any future
2912changes to the internals of the C<CLONE_PARAMS> structure layout, and that
2913it is correctly allocated and initialised.
5076a392 2914
1e463951 2915=head3 New parsing functions
5076a392 2916
1e463951
FC
2917Several functions have been added for parsing statements or multiple
2918statements:
5076a392 2919
1e463951 2920=over
5076a392
FC
2921
2922=item *
2923
1e463951 2924C<parse_fullstmt> parses a complete Perl statement.
5076a392
FC
2925
2926=item *
2927
1e463951
FC
2928C<parse_stmtseq> parses a sequence of statements, up
2929to closing brace or EOF.
5076a392
FC
2930
2931=item *
2932
1e463951 2933C<parse_block> parses a block [perl #78222].
5076a392
FC
2934
2935=item *
2936
1e463951
FC
2937C<parse_barestmt> parses a statement
2938without a label.
5076a392
FC
2939
2940=item *
2941
1e463951 2942C<parse_label> parses a statement label, separate from statements.
5076a392 2943
1e463951 2944=back
5076a392 2945
1e463951
FC
2946The
2947L<C<parse_fullexpr()>|perlapi/parse_fullexpr>,
2948L<C<parse_listexpr()>|perlapi/parse_listexpr>,
2949L<C<parse_termexpr()>|perlapi/parse_termexpr>, and
2950L<C<parse_arithexpr()>|perlapi/parse_arithexpr>
2951functions have been added to the API. They perform
2952recursive-descent parsing of expressions at various precedence levels.
2953They are expected to be used by syntax plugins.
5076a392 2954
1e463951 2955See L<perlapi> for details.
5076a392 2956
1e463951 2957=head3 Hints hash API
5076a392 2958
1e463951
FC
2959A new C API for introspecting the hinthash C<%^H> at runtime has been
2960added. See C<cop_hints_2hv>, C<cop_hints_fetchpvn>, C<cop_hints_fetchpvs>,
2961C<cop_hints_fetchsv>, and C<hv_copy_hints_hv> in L<perlapi> for details.
5076a392 2962
1e463951
FC
2963A new, experimental API has been added for accessing the internal
2964structure that Perl uses for C<%^H>. See the functions beginning with
2965C<cophh_> in L<perlapi>.
5076a392 2966
1e463951 2967=head3 C interface to C<caller()>
5076a392 2968
1e463951
FC
2969The C<caller_cx> function has been added as an XSUB-writer's equivalent of
2970C<caller()>. See L<perlapi> for details.
5076a392 2971
1e463951 2972=head3 Custom per-subroutine check hooks
5076a392 2973
1e463951
FC
2974XS code in an extension module can now annotate a subroutine (whether
2975implemented in XS or in Perl) so that nominated XS code will be called
2976at compile time (specifically as part of op checking) to change the op
2977tree of that subroutine. The compile-time check function (supplied by
2978the extension module) can implement argument processing that can't be
2979expressed as a prototype, generate customised compile-time warnings,
2980perform constant folding for a pure function, inline a subroutine
2981consisting of sufficiently simple ops, replace the whole call with a
2982custom op, and so on. This was previously all possible by hooking the
2983C<entersub> op checker, but the new mechanism makes it easy to tie the
2984hook to a specific subroutine. See L<perlapi/cv_set_call_checker>.
5076a392 2985
1e463951
FC
2986To help in writing custom check hooks, several subtasks within standard
2987C<entersub> op checking have been separated out and exposed in the API.
5076a392 2988
1e463951 2989=head3 Improved support for custom OPs
5076a392 2990
1e463951
FC
2991Custom ops can now be registered with the new C<custom_op_register> C
2992function and the C<XOP> structure. This will make it easier to add new
2993properties of custom ops in the future. Two new properties have been added
2994already, C<xop_class> and C<xop_peep>.
5076a392 2995
1e463951
FC
2996C<xop_class> is one of the OA_*OP constants, and allows L<B> and other
2997introspection mechanisms to work with custom ops
2998that aren't BASEOPs. C<xop_peep> is a pointer to
2999a function that will be called for ops of this
3000type from C<Perl_rpeep>.
5076a392 3001
1e463951
FC
3002See L<perlguts/Custom Operators> and L<perlapi/Custom Operators> for more
3003detail.
5076a392 3004
1e463951
FC
3005The old C<PL_custom_op_names>/C<PL_custom_op_descs> interface is still
3006supported but discouraged.
5076a392 3007
1e463951 3008=head3 Scope hooks
5076a392 3009
1e463951
FC
3010It is now possible for XS code to hook into Perl's lexical scope
3011mechanism at compile time, using the new C<Perl_blockhook_register>
a60ea503 3012function. See L<perlguts/"Compile-time scope hooks">.
5076a392 3013
1e463951 3014=head3 The recursive part of the peephole optimizer is now hookable
5076a392
FC
3015
3016In addition to C<PL_peepp>, for hooking into the toplevel peephole optimizer, a
3017C<PL_rpeepp> is now available to hook into the optimizer recursing into
3018side-chains of the optree.
3019
1e463951 3020=head3 New non-magical variants of existing functions
5076a392 3021
1e463951
FC
3022The following functions/macros have been added to the API. The C<*_nomg>
3023macros are equivalent to their non-_nomg variants, except that they ignore
3024get-magic. Those ending in C<_flags> allow one to specify whether
3025get-magic is processed.
5076a392 3026
1e463951
FC
3027 sv_2bool_flags
3028 SvTRUE_nomg
3029 sv_2nv_flags
3030 SvNV_nomg
3031 sv_cmp_flags
3032 sv_cmp_locale_flags
3033 sv_eq_flags
3034 sv_collxfrm_flags
5076a392 3035
1e463951 3036In some of these cases, the non-_flags functions have
5076a392
FC
3037been replaced with wrappers around the new functions.
3038
1e463951 3039=head3 pv/pvs/sv versions of existing functions
5076a392 3040
1e463951 3041Many functions ending with pvn now have equivalent pv/pvs/sv versions.
5076a392 3042
1e463951 3043=head3 List op-building functions
5076a392 3044
1e463951
FC
3045List op-building functions have been added to the
3046API. See L<op_append_elem|perlapi/op_append_elem>,
3047L<op_append_list|perlapi/op_append_list>, and
3048L<op_prepend_elem|perlapi/op_prepend_elem> in L<perlapi>.
5076a392 3049
1e463951 3050=head3 C<LINKLIST>
5076a392 3051
1e463951
FC
3052The L<LINKLIST|perlapi/LINKLIST> macro, part of op building that
3053constructs the execution-order op chain, has been added to the API.
5076a392 3054
1e463951 3055=head3 Localisation functions
5076a392 3056
1e463951
FC
3057The C<save_freeop>, C<save_op>, C<save_pushi32ptr> and C<save_pushptrptr>
3058functions have been added to the API.
5076a392 3059
1e463951 3060=head3 Stash names
5076a392 3061
1e463951
FC
3062A stash can now have a list of effective names in addition to its usual
3063name. The first effective name can be accessed via the C<HvENAME> macro,
3064which is now the recommended name to use in MRO linearisations (C<HvNAME>
3065being a fallback if there is no C<HvENAME>).
5076a392 3066
1e463951
FC
3067These names are added and deleted via C<hv_ename_add> and
3068C<hv_ename_delete>. These two functions are I<not> part of the API.
5076a392 3069
1e463951 3070=head3 New functions for finding and removing magic
5076a392 3071
1e463951
FC
3072The L<C<mg_findext()>|perlapi/mg_findext> and
3073L<C<sv_unmagicext()>|perlapi/sv_unmagicext>
3074functions have been added to the API.
3075They allow extension authors to find and remove magic attached to
3076scalars based on both the magic type and the magic virtual table, similar to how
3077C<sv_magicext()> attaches magic of a certain type and with a given virtual table
3078to a scalar. This eliminates the need for extensions to walk the list of
3079C<MAGIC> pointers of an C<SV> to find the magic that belongs to them.
5076a392 3080
1e463951 3081=head3 C<find_rundefsv>
5076a392 3082
1e463951
FC
3083This function returns the SV representing C<$_>, whether it's lexical
3084or dynamic.
5076a392 3085
1e463951 3086=head3 C<Perl_croak_no_modify>
5076a392 3087
1e463951
FC
3088C<Perl_croak_no_modify()> is short-hand for
3089C<Perl_croak("%s", PL_no_modify)>.
5076a392 3090
1e463951 3091=head3 C<PERL_STATIC_INLINE> define
5076a392 3092
1e463951
FC
3093The C<PERL_STATIC_INLINE> define has been added to provide the best-guess
3094incantation to use for static inline functions, if the C compiler supports
3095C99-style static inline. If it doesn't, it'll give a plain C<static>.
5076a392 3096
1e463951
FC
3097C<HAS_STATIC_INLINE> can be used to check if the compiler actually supports
3098inline functions.
5076a392 3099
1e463951 3100=head3 New C<pv_escape> option for hexadecimal escapes
5076a392 3101
1e463951
FC
3102A new option, C<PERL_PV_ESCAPE_NONASCII>, has been added to C<pv_escape> to
3103dump all characters above ASCII in hexadecimal. Before, one could get all
3104characters as hexadecimal or the Latin1 non-ASCII as octal.
5076a392 3105
1e463951 3106=head3 C<lex_start>
5076a392 3107
1e463951 3108C<lex_start> has been added to the API, but is considered experimental.
5076a392 3109
1e463951 3110=head3 C<op_scope()> and C<op_lvalue()>
5076a392 3111
1e463951
FC
3112The C<op_scope()> and C<op_lvalue()> functions have been added to the API,
3113but are considered experimental.
5076a392 3114
1e463951 3115=head2 C API Changes
5076a392 3116
1e463951 3117=head3 C<PERL_POLLUTE> has been removed
5076a392 3118
1e463951
FC
3119The option to define C<PERL_POLLUTE> to expose older 5.005 symbols for
3120backwards compatibility has been removed. It's use was always discouraged,
3121and MakeMaker contains a more specific escape hatch:
5076a392 3122
1e463951 3123 perl Makefile.PL POLLUTE=1
5076a392 3124
1e463951
FC
3125This can be used for modules that have not been upgraded to 5.6 naming
3126conventions (and really should be completely obsolete by now).
5076a392 3127
1e463951 3128=head3 Check API compatibility when loading XS modules
5076a392 3129
1e463951
FC
3130When perl's API changes in incompatible ways (which usually happens between
3131major releases), XS modules compiled for previous versions of perl will not
3132work anymore. They will need to be recompiled against the new perl.
5076a392 3133
1e463951
FC
3134In order to ensure that modules are recompiled, and to prevent users from
3135accidentally loading modules compiled for old perls into newer ones, the
3136C<XS_APIVERSION_BOOTCHECK> macro has been added. That macro, which is
3137called when loading every newly compiled extension, compares the API
3138version of the running perl with the version a module has been compiled for
3139and raises an exception if they don't match.
5076a392 3140
1e463951 3141=head3 Perl_fetch_cop_label
5076a392 3142
1e463951
FC
3143The first argument of the C API function C<Perl_fetch_cop_label> has changed
3144from C<struct refcounted he *> to C<COP *>, to insulate the user from
3145implementation details.
5076a392 3146
1e463951
FC
3147This API function was marked as "may change", and likely isn't in use outside
3148the core. (Neither an unpacked CPAN, nor Google's codesearch, finds any other
3149references to it.)
5076a392 3150
1e463951 3151=head3 GvCV() and GvGP() are no longer lvalues
5076a392 3152
1e463951
FC
3153The new GvCV_set() and GvGP_set() macros are now provided to replace
3154assignment to those two macros.
5076a392 3155
1e463951
FC
3156This allows a future commit to eliminate some backref magic between GV
3157and CVs, which will require complete control over assignment to the
3158gp_cv slot.
5076a392 3159
1e463951 3160=head3 CvGV() is no longer an lvalue
5076a392 3161
1e463951
FC
3162Under some circumstances, the C<CvGV()> field of a CV is now
3163reference-counted. To ensure consistent behaviour, direct assignment to
3164it, for example C<CvGV(cv) = gv> is now a compile-time error. A new macro,
3165C<CvGV_set(cv,gv)> has been introduced to perform this operation
3166safely. Note that modification of this field is not part of the public
3167API, regardless of this new macro (and despite its being listed in this section).
5076a392 3168
1e463951 3169=head3 CvSTASH() is no longer an lvalue
5076a392 3170
1e463951
FC
3171The C<CvSTASH()> macro can now only be used as an rvalue. C<CvSTASH_set()>
3172has been added to replace assignment to C<CvSTASH()>. This is to ensure
3173that backreferences are handled properly. These macros are not part of the
3174API.
5076a392 3175
1e463951 3176=head3 Calling conventions for C<newFOROP> and C<newWHILEOP>
5076a392 3177
1e463951
FC
3178The way the parser handles labels has been cleaned up and refactored. As a
3179result, the C<newFOROP()> constructor function no longer takes a parameter
3180stating what label is to go in the state op.
5076a392 3181
1e463951
FC
3182The C<newWHILEOP()> and C<newFOROP()> functions no longer accept a line
3183number as a parameter.
5076a392 3184
1e463951 3185=head3 Flags passed to C<uvuni_to_utf8_flags> and C<utf8n_to_uvuni>
5076a392 3186
1e463951
FC
3187Some of the flags parameters to uvuni_to_utf8_flags() and
3188utf8n_to_uvuni() have changed. This is a result of Perl's now allowing
5076a392
FC
3189internal storage and manipulation of code points that are problematic
3190in some situations. Hence, the default actions for these functions has
3191been complemented to allow these code points. The new flags are
3192documented in L<perlapi>. Code that requires the problematic code
483b16f3 3193points to be rejected needs to change to use the new flags. Some flag
5076a392
FC
3194names are retained for backward source compatibility, though they do
3195nothing, as they are now the default. However the flags
3196C<UNICODE_ALLOW_FDD0>, C<UNICODE_ALLOW_FFFF>, C<UNICODE_ILLEGAL>, and
3197C<UNICODE_IS_ILLEGAL> have been removed, as they stem from a
3198fundamentally broken model of how the Unicode non-character code points
3199should be handled, which is now described in
3200L<perlunicode/Non-character code points>. See also L</Selected Bug Fixes>.
3201
1e463951 3202XXX Which bugs in particular? Selected Bug Fixes is too long for this link
483b16f3
KW
3203to be meaningful right now
3204I don't see the bugs in that section currently -- khw
5076a392 3205
1e463951 3206=head2 Deprecated C APIs
5076a392 3207
1e463951 3208=over
5076a392 3209
1e463951 3210=item C<Perl_ptr_table_clear>
5076a392 3211
1e463951
FC
3212C<Perl_ptr_table_clear> is no longer part of Perl's public API. Calling it
3213now generates a deprecation warning, and it will be removed in a future
3214release.
5076a392 3215
1e463951 3216=item C<sv_compile_2op>
5076a392 3217
1e463951
FC
3218The C<sv_compile_2op()> API function is now deprecated. Searches suggest
3219that nothing on CPAN is using it, so this should have zero impact.
5076a392 3220
1e463951
FC
3221It attempted to provide an API to compile code down to an optree, but failed
3222to bind correctly to lexicals in the enclosing scope. It's not possible to
3223fix this problem within the constraints of its parameters and return value.
5076a392 3224
1e463951 3225=item C<find_rundefsvoffset>
5076a392 3226
1e463951
FC
3227The C<find_rundefsvoffset> function has been deprecated. It appeared that
3228its design was insufficient for reliably getting the lexical C<$_> at
3229run-time.
5076a392 3230
1e463951 3231Use the new C<find_rundefsv> function or the C<UNDERBAR> macro
cbb8c2bc
FC
3232instead. They directly return the right SV
3233representing C<$_>, whether it's
1e463951 3234lexical or dynamic.
5076a392 3235
1e463951 3236=item C<CALL_FPTR> and C<CPERLscope>
5076a392 3237
1e463951
FC
3238Those are left from an old implementation of C<MULTIPLICITY> using C++ objects,
3239which was removed in Perl 5.8. Nowadays these macros do exactly nothing, so
3240they shouldn't be used anymore.
5076a392 3241
1e463951
FC
3242For compatibility, they are still defined for external C<XS> code. Only
3243extensions defining C<PERL_CORE> must be updated now.
5076a392 3244
1e463951 3245=back
5076a392 3246
1e463951 3247=head2 Other Internal Changes
5076a392 3248
1e463951 3249=head3 Stack unwinding
5076a392 3250
1e463951
FC
3251The protocol for unwinding the C stack at the last stage of a C<die>
3252has changed how it identifies the target stack frame. This now uses
3253a separate variable C<PL_restartjmpenv>, where previously it relied on
3254the C<blk_eval.cur_top_env> pointer in the C<eval> context frame that
3255has nominally just been discarded. This change means that code running
3256during various stages of Perl-level unwinding no longer needs to take
3257care to avoid destroying the ghost frame.
5076a392 3258
1e463951 3259=head3 Scope stack entries
5076a392 3260
1e463951
FC
3261The format of entries on the scope stack has been changed, resulting in a
3262reduction of memory usage of about 10%. In particular, the memory used by
3263the scope stack to record each active lexical variable has been halved.
5076a392 3264
1e463951 3265=head3 Memory allocation for pointer tables
5076a392 3266
1e463951
FC
3267Memory allocation for pointer tables has been changed. Previously
3268C<Perl_ptr_table_store> allocated memory from the same arena system as
3269C<SV> bodies and C<HE>s, with freed memory remaining bound to those arenas
3270until interpreter exit. Now it allocates memory from arenas private to the
3271specific pointer table, and that memory is returned to the system when
3272C<Perl_ptr_table_free> is called. Additionally, allocation and release are
3273both less CPU intensive.
5076a392 3274
1e463951 3275=head3 C<UNDERBAR>
5076a392 3276
1e463951
FC
3277The C<UNDERBAR> macro now calls C<find_rundefsv>. C<dUNDERBAR> is now a
3278noop but should still be used to ensure past and future compatibility.
5076a392 3279
1e463951 3280=head3 String comparison routines renamed
5076a392 3281
1e463951
FC
3282The ibcmp_* functions have been renamed and are now called foldEQ,
3283foldEQ_locale and foldEQ_utf8. The old names are still available as
3284macros.
3285
3286=head3 C<chop> and C<chomp> implementations merged
3287
3288The opcode bodies for C<chop> and C<chomp> and for C<schop> and C<schomp>
3289have been merged. The implementation functions C<Perl_do_chop()> and
3290C<Perl_do_chomp()>, never part of the public API, have been merged and
3291moved to a static function in F<pp.c>. This shrinks the perl binary
3292slightly, and should not affect any code outside the core (unless it is
3293relying on the order of side effects when C<chomp> is passed a I<list> of
3294values).
5076a392
FC
3295
3296=head1 Selected Bug Fixes
3297
e8e35311
FC
3298=head2 I/O
3299
5076a392
FC
3300=over 4
3301
3302=item *
3303
e8e35311 3304Perl no longer produces this warning:
a593b319
FC
3305
3306 $ perl -we 'open my $f, ">", \my $x; binmode $f, "scalar"'
3307 Use of uninitialized value in binmode at -e line 1.
3308
3309=item *
3310
e8e35311
FC
3311Opening a glob reference via C<< open $fh, "E<gt>", \*glob >> will no longer
3312cause the glob to be corrupted when the filehandle is printed to. This would
3313cause perl to crash whenever the glob's contents were accessed
3314[perl #77492].
4ed2cea4
FC
3315
3316=item *
3317
e8e35311 3318PerlIO no longer crashes when called recursively, e.g., from a signal
cbb8c2bc 3319handler. Now it just leaks memory [perl #75556].
4ed2cea4
FC
3320
3321=item *
3322
e8e35311 3323Most I/O functions were not warning for unopened handles unless the
cbb8c2bc 3324'closed' and 'unopened' warnings categories were both enabled. Now only
e8e35311 3325C<use warnings 'unopened'> is necessary to trigger these warnings (as was
438c239f 3326always meant to be the case).
4ed2cea4
FC
3327
3328=item *
3329
438c239f 3330There have been several fixes to PerlIO layers:
e8e35311 3331
438c239f
FC
3332When C<binmode FH, ":crlf"> pushes the C<:crlf> layer on top of the stack,
3333it no longer enables crlf layers lower in the stack, to avoid unexpected
3334results [perl #38456].
4ed2cea4 3335
438c239f
FC
3336Opening a file in C<:raw> mode now does what it advertises to do (first
3337open the file, then binmode it), instead of simply leaving off the top
3338layer [perl #80764].
5076a392 3339
438c239f
FC
3340The three layers C<:pop>, C<:utf8> and C<:bytes> didn't allow stacking when
3341opening a file. For example
e8e35311 3342this:
5076a392 3343
e8e35311 3344 open FH, '>:pop:perlio', 'some.file' or die $!;
5076a392 3345
438c239f
FC
3346Would throw an error: "Invalid argument". This has been fixed in this
3347release [perl #82484].
5076a392 3348
e8e35311
FC
3349=back
3350
3351=head2 Regular Expression Bug Fixes
3352
3353=over
5076a392
FC
3354
3355=item *
3356
e8e35311
FC
3357The regular expression engine no longer loops when matching
3358C<"\N{LATIN SMALL LIGATURE FF}" =~ /f+/i> and similar expressions
cdc10f43 3359[perl #72998] (5.12.1).
5076a392
FC
3360
3361=item *
3362
e8e35311
FC
3363The trie runtime code should no longer allocate massive amounts of memory,
3364fixing #74484.
5076a392
FC
3365
3366=item *
3367
438c239f
FC
3368Syntax errors in C<< (?{...}) >> blocks no longer cause panic messages
3369[perl #2353].
5076a392
FC
3370
3371=item *
3372
438c239f
FC
3373A pattern like C<(?:(o){2})?> no longer causes a "panic" error
3374[perl #39233].
5076a392
FC
3375
3376=item *
3377
438c239f 3378A fatal error in regular expressions containing C<(.*?)> when processing
d430b8e7 3379UTF-8 data has been fixed [perl #75680] (5.12.2).
5076a392
FC
3380
3381=item *
3382
e8e35311 3383An erroneous regular expression engine optimisation that caused regex verbs like
438c239f 3384C<*COMMIT> sometimes to be ignored has been removed.
5076a392
FC
3385
3386=item *
3387
e8e35311
FC
3388The regular expression bracketed character class C<[\8\9]> was effectively the
3389same as C<[89\000]>, incorrectly matching a NULL character. It also gave
3390incorrect warnings that the C<8> and C<9> were ignored. Now C<[\8\9]> is the
3391same as C<[89]> and gives legitimate warnings that C<\8> and C<\9> are
3392unrecognized escape sequences, passed-through.
5076a392
FC
3393
3394=item *
3395
e8e35311
FC
3396A regular expression match in the right-hand side of a global substitution
3397(C<s///g>) that is in the same scope will no longer cause match variables
cbb8c2bc 3398to have the wrong values on subsequent iterations. This can happen when an
e8e35311
FC
3399array or hash subscript is interpolated in the right-hand side, as in
3400C<s|(.)|@a{ print($1), /./ }|g> [perl #19078].
5076a392
FC
3401
3402=item *
3403
438c239f
FC
3404Several cases in which characters in the Latin-1 non-ASCII range (0x80 to
34050xFF) used not to match themselves or used to match both a character class
3406and its complement have been fixed. For instance, U+00E2 could match both
3407C<\w> and C<\W> [perl #78464] [perl #18281] [perl #60156].
5076a392
FC
3408
3409=item *
3410
e8e35311
FC
3411Matching a Unicode character against an alternation containing characters
3412that happened to match continuation bytes in the former's UTF8
3413representation (C<qq{\x{30ab}} =~ /\xab|\xa9/>) would cause erroneous
3414warnings [perl #70998].
5076a392
FC
3415
3416=item *
3417
e8e35311
FC
3418The trie optimisation was not taking empty groups into account, preventing
3419'foo' from matching C</\A(?:(?:)foo|bar|zot)\z/> [perl #78356].
5076a392
FC
3420
3421=item *
3422
e8e35311
FC
3423A pattern containing a C<+> inside a lookahead would sometimes cause an
3424incorrect match failure in a global match (e.g., C</(?=(\S+))/g>)
3425[perl #68564].
5076a392
FC
3426
3427=item *
3428
e8e35311
FC
3429A regular expression optimisation would sometimes cause a match with a
3430C<{n,m}> quantifier to fail when it should match [perl #79152].
5076a392
FC
3431
3432=item *
3433
e8e35311 3434Case insensitive matching in regular expressions compiled under C<use
438c239f
FC
3435locale> now works much more sanely when the pattern or
3436target string is encoded internally in
3437UTF8. Previously, under these conditions the localeness
e8e35311
FC
3438was completely lost. Now, code points above 255 are treated as Unicode,
3439but code points between 0 and 255 are treated using the current locale
438c239f
FC
3440rules, regardless of whether the pattern or the string is encoded in UTF8.
3441The few case-insensitive matches that cross the 255/256 boundary are not
e8e35311
FC
3442allowed. For example, 0xFF does not caselessly match the character at
34430x178, LATIN CAPITAL LETTER Y WITH DIAERESIS, because 0xFF may not be
3444LATIN SMALL LETTER Y in the current locale, and Perl has no way of
3445knowing if that character even exists in the locale, much less what code
3446point it is.
5076a392
FC
3447
3448=item *
3449
e8e35311 3450The C<(?|...)> regular expression construct no longer crashes if the final
cbb8c2bc 3451branch has more sets of capturing parentheses than any other branch. This
e8e35311
FC
3452was fixed in Perl 5.10.1 for the case of a single branch, but that fix did
3453not take multiple branches into account [perl #84746].
5076a392
FC
3454
3455=item *
3456
e8e35311
FC
3457A bug has been fixed in the implementation of C<{...}> quantifiers in
3458regular expressions that prevented the code block in
3459C</((\w+)(?{ print $2 })){2}/> from seeing the C<$2> sometimes
3460[perl #84294].
5076a392 3461
e8e35311 3462=back
5076a392 3463
e8e35311
FC
3464=head2 Syntax/Parsing Bugs
3465
3466=over
5076a392
FC
3467
3468=item *
3469
e8e35311 3470C<when(scalar){...}> no longer crashes, but produces a syntax error
cdc10f43 3471[perl #74114] (5.12.1).
5076a392
FC
3472
3473=item *
3474
e8e35311
FC
3475A label right before a string eval (C<foo: eval $string>) no longer causes
3476the label to be associated also with the first statement inside the eval
3477[perl #74290] (5.12.1).
5076a392
FC
3478
3479=item *
3480
b2c076b5 3481The C<no 5.13.2;> form of C<no> no longer tries to turn on features or
d430b8e7 3482pragmata (i.e., strict) [perl #70075] (5.12.2).
5076a392
FC
3483
3484=item *
3485
b2c076b5
FC
3486C<BEGIN {require 5.12.0}> now behaves as documented, rather than behaving
3487identically to C<use 5.12.0;>. Previously, C<require> in a C<BEGIN> block
3488was erroneously executing the C<use feature ':5.12.0'> and
3489C<use strict;> behaviour, which only C<use> was documented to
3490provide [perl #69050].
5076a392
FC
3491
3492=item *
3493
5076a392
FC
3494A regression introduced in Perl 5.12.0, making
3495C<< my $x = 3; $x = length(undef) >> result in C<$x> set to C<3> has been
d430b8e7 3496fixed. C<$x> will now be C<undef> [perl #85508] (5.12.2).
b2c076b5
FC
3497
3498=item *
3499
3500When strict 'refs' mode is off, C<%{...}> in rvalue context returns
3501C<undef> if its argument is undefined. An optimisation introduced in perl
35025.12.0 to make C<keys %{...}> faster when used as a boolean did not take
3503this into account, causing C<keys %{+undef}> (and C<keys %$foo> when
3504C<$foo> is undefined) to be an error, which it should only be in strict
3505mode [perl #81750].
5076a392
FC
3506
3507=item *
3508