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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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FC
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
61752d82
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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
61752d82
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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
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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
FC
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<${"foo::!"}> (with strict mode off) to access C's C<errno>, etc.
684
685This was a bug, or an 'unintentional' feature, which caused various ill effects,
686such as signal handlers being wiped when modules were loaded, etc.
687
688This has been fixed (or the feature has been removed, depending on how you see
689it).
690
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FC
691=head3 local($_) will strip all magic from $_
692
693local() on scalar variables will give them a new value, but keep all
694their magic intact. This has proven to be problematic for the default
695scalar variable $_, where L<perlsub> recommends that any subroutine
696that assigns to $_ should localize it first. This would throw an
697exception if $_ is aliased to a read-only variable, and could have
698various unintentional side-effects in general.
699
700Therefore, as an exception to the general rule, local($_) will not
701only assign a new value to $_, but also remove all existing magic from
702it as well.
703
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704=head2 Changes to Syntax or to Perl Operators
705
706=head3 C<given> return values
707
708C<given> blocks now return the last evaluated
709expression, or an empty list if the block was exited by C<break>. Thus you
710can now write:
711
712 my $type = do {
713 given ($num) {
714 break when undef;
715 'integer' when /^[+-]?[0-9]+$/;
716 'float' when /^[+-]?[0-9]+(?:\.[0-9]+)?$/;
717 'unknown';
718 }
719 };
720
721See L<perlsyn/Return value> for details.
722
723=head3 Change in the parsing of certain prototypes
724
725Functions declared with the following prototypes now behave correctly as unary
726functions:
727
728 *
729 \$ \% \@ \* \&
730 \[...]
731 ;$ ;*
732 ;\$ ;\% etc.
733 ;\[...]
734
735Due to this bug fix [perl #75904], functions
736using the C<(*)>, C<(;$)> and C<(;*)> prototypes
179813a8
FC
737are parsed with higher precedence than before. So
738in the following example:
61752d82
FC
739
740 sub foo($);
741 foo $a < $b;
742
743the second line is now parsed correctly as C<< foo($a) < $b >>, rather than
179813a8 744C<< foo($a < $b) >>. This happens when one of these operators is used in
61752d82
FC
745an unparenthesised argument:
746
747 < > <= >= lt gt le ge
748 == != <=> eq ne cmp ~~
749 &
750 | ^
751 &&
752 || //
753 .. ...
754 ?:
755 = += -= *= etc.
756
757=head3 Smart-matching against array slices
758
759Previously, the following code resulted in a successful match:
760
761 my @a = qw(a y0 z);
762 my @b = qw(a x0 z);
763 @a[0 .. $#b] ~~ @b;
764
765This odd behaviour has now been fixed [perl #77468].
766
767=head3 Negation treats strings differently from before
768
769The unary negation operator C<-> now treats strings that look like numbers
770as numbers [perl #57706].
771
772=head3 Negative zero
773
774Negative zero (-0.0), when converted to a string, now becomes "0" on all
179813a8 775platforms. It used to become "-0" on some, but "0" on others.
61752d82
FC
776
777If you still need to determine whether a zero is negative, use
778C<sprintf("%g", $zero) =~ /^-/> or the L<Data::Float> module on CPAN.
779
780=head3 C<:=> is now a syntax error
5076a392
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781
782Previously C<my $pi := 4;> was exactly equivalent to C<my $pi : = 4;>,
783with the C<:> being treated as the start of an attribute list, ending before
179813a8
FC
784the C<=>. The use of C<:=> to mean C<: => was deprecated in 5.12.0, and is
785now a syntax error. This will allow the future use of C<:=> as a new
786token.
5076a392
FC
787
788We find no Perl 5 code on CPAN using this construction, outside the core's
789tests for it, so we believe that this change will have very little impact on
790real-world codebases.
791
792If it is absolutely necessary to have empty attribute lists (for example,
793because of a code generator) then avoid the error by adding a space before
794the C<=>.
795
61752d82 796=head2 Threads and Processes
5076a392 797
61752d82 798=head3 Directory handles not copied to threads
5076a392 799
61752d82
FC
800On systems other than Windows that do not have
801a C<fchdir> function, newly-created threads no
179813a8 802longer inherit directory handles from their parent threads. Such programs
61752d82 803would usually have crashed anyway [perl #75154].
5076a392 804
61752d82 805=head3 C<close> on shared pipes
5076a392 806
61752d82
FC
807The C<close> function no longer waits for the child process to exit if the
808underlying file descriptor is still in use by another thread, to avoid
179813a8 809deadlocks. It returns true in such cases.
5076a392 810
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FC
811=head3 fork() emulation will not wait for signalled children
812
813On Windows parent processes would not terminate until all forked
814childred had terminated first. However, C<kill('KILL', ...)> is
815inherently unstable on pseudo-processes, and C<kill('TERM', ...)>
179813a8 816might not get delivered if the child is blocked in a system call.
144b6ea2
FC
817
818To avoid the deadlock and still provide a safe mechanism to terminate
819the hosting process, Perl will now no longer wait for children that
820have been sent a SIGTERM signal. It is up to the parent process to
821waitpid() for these children if child clean-up processing must be
179813a8 822allowed to finish. However, it is also the responsibility of the
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FC
823parent then to avoid the deadlock by making sure the child process
824can't be blocked on I/O either.
825
826See L<perlfork> for more information about the fork() emulation on
827Windows.
828
61752d82 829=head2 Configuration
5076a392 830
61752d82 831=head3 Naming fixes in Policy_sh.SH may invalidate Policy.sh
5076a392 832
61752d82
FC
833Several long-standing typos and naming confusions in Policy_sh.SH have
834been fixed, standardizing on the variable names used in config.sh.
5076a392 835
61752d82 836This will change the behavior of Policy.sh if you happen to have been
179813a8 837accidentally relying on its incorrect behavior.
f318e2e6 838
5a1f7719
FC
839=head3 Perl source code is read in text mode on Windows
840
841Perl scripts used to be read in binary mode on Windows for the benefit
842of the ByteLoader module (which is no longer part of core Perl). This
843had the side effect of breaking various operations on the DATA filehandle,
844including seek()/tell(), and even simply reading from DATA after file handles
845have been flushed by a call to system(), backticks, fork() etc.
846
847The default build options for Windows have been changed to read Perl source
848code on Windows in text mode now. Hopefully ByteLoader will be updated on
849CPAN to automatically handle this situation [perl #28106].
850
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851=head1 Deprecations
852
1e463951
FC
853See also L</Deprecated C APIs>.
854
5076a392
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855=head2 Omitting a space between a regular expression and subsequent word
856
18139a1b
FC
857Omitting a space between a regular expression operator or
858its modifiers and the following word is deprecated. For
859example, C<< m/foo/sand $bar >> will still be parsed
860as C<< m/foo/s and $bar >> but will issue a warning.
5076a392 861
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862=head2 C<\cI<X>>
863
864The backslash-c construct was designed as a way of specifying
865non-printable characters, but there were no restrictions (on ASCII
866platforms) on what the character following the C<c> could be. Now,
867a deprecation warning is raised if that character isn't an ASCII character.
868Also, a deprecation warning is raised for C<"\c{"> (which is the same
869as simply saying C<";">).
870
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871=head2 C<"\b{"> and C<"\B{">
872
873In regular expressions, a literal C<"{"> immediately following a C<"\b">
874(not in a bracketed character class) or a C<"\B{"> is now deprecated
875to allow for its future use by Perl itself.
876
5076a392
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877=head2 Deprecation warning added for deprecated-in-core .pl libs
878
879This is a mandatory warning, not obeying -X or lexical warning bits.
880The warning is modelled on that supplied by deprecate.pm for
881deprecated-in-core .pm libraries. It points to the specific CPAN
823d0e46
FC
882distribution that contains the .pl libraries. The CPAN version, of
883course, does not generate the warning.
5076a392
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884
885=head2 List assignment to C<$[>
886
823d0e46
FC
887Assignment to C<$[> was deprecated and started to give warnings in
888Perl version 5.12.0. This version of perl also starts to emit a warning when
889assigning to C<$[> in list context. This fixes an oversight in 5.12.0.
5076a392
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890
891=head2 Use of qw(...) as parentheses
892
893Historically the parser fooled itself into thinking that C<qw(...)> literals
894were always enclosed in parentheses, and as a result you could sometimes omit
895parentheses around them:
896
897 for $x qw(a b c) { ... }
898
899The parser no longer lies to itself in this way. Wrap the list literal in
823d0e46 900parentheses, like this:
5076a392
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901
902 for $x (qw(a b c)) { ... }
903
904=head2 C<\N{BELL}> is deprecated
905
906This is because Unicode is using that name for a different character.
907See L</Unicode Version 6.0 is now supported (mostly)> for more
908explanation.
909
910=head2 C<?PATTERN?> is deprecated
911
912C<?PATTERN?> (without the initial m) has been deprecated and now produces
913a warning. This is to allow future use of C<?> in new operators.
914The match-once functionality is still available in the form of C<m?PATTERN?>.
915
5076a392
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916=head2 Tie functions on scalars holding typeglobs
917
918Calling a tie function (C<tie>, C<tied>, C<untie>) with a scalar argument
919acts on a file handle if the scalar happens to hold a typeglob.
920
921This is a long-standing bug that will be removed in Perl 5.16, as
922there is currently no way to tie the scalar itself when it holds
923a typeglob, and no way to untie a scalar that has had a typeglob
924assigned to it.
925
823d0e46 926Now there is a deprecation warning whenever a tie
5076a392
FC
927function is used on a handle without an explicit C<*>.
928
18139a1b 929=head2 User-defined case-mapping
5076a392 930
18139a1b
FC
931This feature is being deprecated due to its many issues, as documented in
932L<perlunicode/User-Defined Case Mappings (for serious hackers only)>.
e48f36f0
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933It is planned to remove this feature in Perl 5.16. Instead use the CPAN module
934L<Unicode::Casing>, which provides improved functionality.
823d0e46 935
18139a1b 936=head2 Deprecated modules
5076a392
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937
938The following modules will be removed from the core distribution in a
939future release, and should be installed from CPAN instead. Distributions
a60ea503 940on CPAN which require these should add them to their prerequisites. The
823d0e46 941core versions of these modules will issue a deprecation warning.
5076a392
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942
943If you ship a packaged version of Perl, either alone or as part of a
944larger system, then you should carefully consider the repercussions of
823d0e46 945core module deprecations. You may want to consider shipping your default
5076a392 946build of Perl with packages for some or all deprecated modules which
823d0e46 947install into C<vendor> or C<site> perl library directories. This will
5076a392
FC
948inhibit the deprecation warnings.
949
950Alternatively, you may want to consider patching F<lib/deprecate.pm>
951to provide deprecation warnings specific to your packaging system
952or distribution of Perl, consistent with how your packaging system
953or distribution manages a staged transition from a release where the
954installation of a single package provides the given functionality, to
955a later release where the system administrator needs to know to install
956multiple packages to get that same functionality.
957
958You can silence these deprecation warnings by installing the modules
959in question from CPAN. To install the latest version of all of them,
960just install C<Task::Deprecations::5_14>.
961
962=over
963
964=item L<Devel::DProf>
965
966We strongly recommend that you install and used L<Devel::NYTProf> in
967preference, as it offers significantly improved profiling and reporting.
968
969=back
970
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971=head1 Performance Enhancements
972
54c7bb16 973=head2 "Safe signals" optimisation
df91d470 974
a60ea503 975Signal dispatch has been moved from the runloop into control ops. This
df91d470
FC
976should give a few percent speed increase, and eliminates almost all of
977the speed penalty caused by the introduction of "safe signals" in
a60ea503 9785.8.0. Signals should still be dispatched within the same statement as
df91d470
FC
979they were previously - if this is not the case, or it is possible to
980create uninterruptible loops, this is a bug, and reports are encouraged
981of how to recreate such issues.
982
54c7bb16 983=head2 Optimisation of shift; and pop; calls without arguments
df91d470 984
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FC
985Two fewer OPs are used for shift and pop calls with no argument (with
986implicit C<@_>). This change makes C<shift;> 5% faster than C<shift @_;>
987on non-threaded perls and 25% faster on threaded.
df91d470 988
fa232254 989=head2 Optimisation of regexp engine string comparison work
df91d470 990
fa232254
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991The foldEQ_utf8 API function for case-insensitive comparison of strings (which
992is used heavily by the regexp engine) was substantially refactored and
993optimised - and its documentation much improved as a free bonus gift.
df91d470 994
fa232254 995=head2 Regular expression compilation speed-up
df91d470 996
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FC
997Compiling regular expressions has been made faster for the case where upgrading
998the regex to utf8 is necessary but that isn't known when the compilation begins.
df91d470 999
fa232254 1000=head2 String appending is 100 times faster
df91d470 1001
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FC
1002When doing a lot of string appending, perl could end up allocating a lot more
1003memory than needed in a very inefficient way, if perl was configured to use the
1004system's C<malloc> implementation instead of its own.
1005
1006C<sv_grow>, which is what's being used to allocate more memory if necessary
1007when appending to a string, has now been taught how to round up the memory
1008it requests to a certain geometric progression, making it much faster on
1009certain platforms and configurations. On Win32, it's now about 100 times
1010faster.
1011
1012=head2 Eliminate C<PL_*> accessor functions under ithreads
1013
1014When C<MULTIPLICITY> was first developed, and interpreter state moved into
1015an interpreter struct, thread and interpreter local C<PL_*> variables were
1016defined as macros that called accessor functions, returning the address of
1017the value, outside of the perl core. The intent was to allow members
1018within the interpreter struct to change size without breaking binary
1019compatibility, so that bug fixes could be merged to a maintenance branch
1020that necessitated such a size change.
1021
1022However, some non-core code defines C<PERL_CORE>, sometimes intentionally
1023to bypass this mechanism for speed reasons, sometimes for other reasons but
1024with the inadvertent side effect of bypassing this mechanism. As some of
1025this code is widespread in production use, the result is that the core
1026I<can't> change the size of members of the interpreter struct, as it will
1027break such modules compiled against a previous release on that maintenance
1028branch. The upshot is that this mechanism is redundant, and well-behaved
1029code is penalised by it. Hence it can and should be removed (and has
1030been).
1031
1032=head2 Freeing weak references
1033
1034When an object has many weak references to it, freeing that object
1035can under some some circumstances take O(N^2) time to free (where N is the
a60ea503 1036number of references). The number of circumstances has been reduced
fa232254
FC
1037[perl #75254]
1038
1039=head2 Lexical array and hash assignments
1040
1041An earlier optimisation to speed up C<my @array = ...> and
1042C<my %hash = ...> assignments caused a bug and was disabled in Perl 5.12.0.
1043
1044Now we have found another way to speed up these assignments [perl #82110].
df91d470 1045
111b6aa7 1046=head2 C<@_> uses less memory
df91d470 1047
111b6aa7
FC
1048Previously, C<@_> was allocated for every subroutine at compile time with
1049enough space for four entries. Now this allocation is done on demand when
1050the subroutine is called [perl #72416].
5076a392 1051
5076a392
FC
1052=head2 Size optimisations to SV and HV structures
1053
1054xhv_fill has been eliminated from struct xpvhv, saving 1 IV per hash and
a60ea503 1055on some systems will cause struct xpvhv to become cache-aligned. To avoid
5076a392
FC
1056this memory saving causing a slowdown elsewhere, boolean use of HvFILL
1057now calls HvTOTALKEYS instead (which is equivalent) - so while the fill
111b6aa7
FC
1058data when actually required are now calculated on demand, the cases when
1059this needs to be done should be few and far between.
5076a392 1060
111b6aa7
FC
1061The order of structure elements in SV bodies has changed. Effectively,
1062the NV slot has swapped location with STASH and MAGIC. As all access to
1063SV members is via macros, this should be completely transparent. This
5076a392
FC
1064change allows the space saving for PVHVs documented above, and may reduce
1065the memory allocation needed for PVIVs on some architectures.
1066
fa232254
FC
1067C<XPV>, C<XPVIV>, and C<XPVNV> now only allocate the parts of the C<SV> body
1068they actually use, saving some space.
5076a392 1069
fa232254
FC
1070Scalars containing regular expressions now only allocate the part of the C<SV>
1071body they actually use, saving some space.
5076a392
FC
1072
1073=head2 Memory consumption improvements to Exporter
1074
1075The @EXPORT_FAIL AV is no longer created unless required, hence neither is
111b6aa7
FC
1076the typeglob backing it. This saves about 200 bytes for every package that
1077uses Exporter but doesn't use this functionality.
5076a392 1078
111b6aa7 1079=head2 Memory savings for weak references
5076a392
FC
1080
1081For weak references, the common case of just a single weak reference per
a60ea503
FC
1082referent has been optimised to reduce the
1083storage required. In this case it
111b6aa7 1084saves the equivalent of one small Perl array per referent.
5076a392 1085
111b6aa7 1086=head2 C<%+> and C<%-> use less memory
5076a392
FC
1087
1088The bulk of the C<Tie::Hash::NamedCapture> module used to be in the perl
111b6aa7 1089core. It has now been moved to an XS module, to reduce the overhead for
5076a392
FC
1090programs that do not use C<%+> or C<%->.
1091
fa232254 1092=head2 Multiple small improvements to threads
5076a392 1093
fa232254
FC
1094The internal structures of threading now make fewer API calls and fewer
1095allocations, resulting in noticeably smaller object code. Additionally,
1096many thread context checks have been deferred so that they're only done
1097when required (although this is only possible for non-debugging builds).
5076a392 1098
fa232254 1099=head2 Adjacent pairs of nextstate opcodes are now optimized away
5076a392 1100
fa232254 1101Previously, in code such as
5076a392 1102
fa232254 1103 use constant DEBUG => 0;
5076a392 1104
fa232254
FC
1105 sub GAK {
1106 warn if DEBUG;
1107 print "stuff\n";
1108 }
5076a392 1109
fa232254
FC
1110the ops for C<warn if DEBUG;> would be folded to a C<null> op (C<ex-const>), but
1111the C<nextstate> op would remain, resulting in a runtime op dispatch of
1112C<nextstate>, C<nextstate>, ....
5076a392 1113
fa232254
FC
1114The execution of a sequence of C<nextstate> ops is indistinguishable from just
1115the last C<nextstate> op so the peephole optimizer now eliminates the first of
1116a pair of C<nextstate> ops, except where the first carries a label, since labels
1117must not be eliminated by the optimizer and label usage isn't conclusively known
1118at compile time.
5076a392
FC
1119
1120=head1 Modules and Pragmata
1121
1122=head2 New Modules and Pragmata
1123
1124=over 4
1125
1126=item *
1127
1128C<CPAN::Meta::YAML> 0.003 has been added as a dual-life module. It supports a
1129subset of YAML sufficient for reading and writing META.yml and MYMETA.yml files
1130included with CPAN distributions or generated by the module installation
a60ea503 1131toolchain. It should not be used for any other general YAML parsing or
5076a392
FC
1132generation task.
1133
1134=item *
1135
a60ea503 1136C<CPAN::Meta> version 2.110440 has been added as a dual-life module. It
5076a392
FC
1137provides a standard library to read, interpret and write CPAN distribution
1138metadata files (e.g. META.json and META.yml) which describes a
1139distribution, its contents, and the requirements for building it and
a60ea503 1140installing it. The latest CPAN distribution metadata specification is
5076a392
FC
1141included as C<CPAN::Meta::Spec> and notes on changes in the specification
1142over time are given in C<CPAN::Meta::History>.
1143
1144=item *
1145
c0331f42 1146C<HTTP::Tiny> 0.012 has been added as a dual-life module. It is a very
5076a392
FC
1147small, simple HTTP/1.1 client designed for simple GET requests and file
1148mirroring. It has has been added to enable CPAN.pm and CPANPLUS to
1149"bootstrap" HTTP access to CPAN using pure Perl without relying on external
1150binaries like F<curl> or F<wget>.
1151
1152=item *
1153
1154C<JSON::PP> 2.27105 has been added as a dual-life module, for the sake of
1155reading F<META.json> files in CPAN distributions.
1156
1157=item *
1158
21ef4e45 1159C<Module::Metadata> 1.000004 has been added as a dual-life module. It gathers
5076a392
FC
1160package and POD information from Perl module files. It is a standalone module
1161based on Module::Build::ModuleInfo for use by other module installation
1162toolchain components. Module::Build::ModuleInfo has been deprecated in
1163favor of this module instead.
1164
1165=item *
1166
1167C<Perl::OSType> 1.002 has been added as a dual-life module. It maps Perl
1168operating system names (e.g. 'dragonfly' or 'MSWin32') to more generic types
1169with standardized names (e.g. "Unix" or "Windows"). It has been refactored
1170out of Module::Build and ExtUtils::CBuilder and consolidates such mappings into
1171a single location for easier maintenance.
1172
1173=item *
1174
1175The following modules were added by the C<Unicode::Collate>
a60ea503 1176upgrade. See below for details.
5076a392
FC
1177
1178C<Unicode::Collate::CJK::Big5>
1179
1180C<Unicode::Collate::CJK::GB2312>
1181
1182C<Unicode::Collate::CJK::JISX0208>
1183
1184C<Unicode::Collate::CJK::Korean>
1185
1186C<Unicode::Collate::CJK::Pinyin>
1187
1188C<Unicode::Collate::CJK::Stroke>
1189
1190=item *
1191
1192C<Version::Requirements> version 0.101020 has been added as a dual-life
1193module. It provides a standard library to model and manipulates module
1194prerequisites and version constraints as defined in the L<CPAN::Meta::Spec>.
1195
1196=back
1197
a5794e94 1198=head2 Updated Modules and Pragma
5076a392
FC
1199
1200=over 4
1201
1202=item *
1203
81a53be2
FR
1204C<attributes> has been upgraded from version 0.12 to 0.14.
1205
1206=item *
1207
5076a392
FC
1208C<Archive::Extract> has been upgraded from version 0.38 to 0.48.
1209
1210Updates since 0.38 include: a safe print method that guards
1211Archive::Extract from changes to $\; a fix to the tests when run in core
1984204c
FC
1212perl; support for TZ files; a modification for the lzma
1213logic to favour IO::Uncompress::Unlzma; and a fix
1214for an issue with NetBSD-current and its new unzip
5076a392
FC
1215executable.
1216
1217=item *
1218
1219C<Archive::Tar> has been upgraded from version 1.54 to 1.76.
1220
1984204c
FC
1221Important changes since 1.54 include the following:
1222
1223=over
1224
1225=item *
1226
1227Compatibility with busybox implementations of tar
1228
1229=item *
1230
1231A fix so that C<write()> and C<create_archive()>
1232close only handles they opened
1233
1234=item *
1235
1236A bug was fixed regarding the exit code of extract_archive.
5076a392 1237
1984204c
FC
1238=item *
1239
4f978a3b 1240The C<ptar> utility has a new option to allow safe
5076a392
FC
1241creation of tarballs without world-writable files on Windows, allowing those
1242archives to be uploaded to CPAN.
1243
1984204c
FC
1244=item *
1245
1246A new ptargrep utility for using regular expressions against
5076a392
FC
1247the contents of files in a tar archive.
1248
1984204c
FC
1249=item *
1250
1251Pax extended headers are now skipped.
1252
1253=back
5076a392
FC
1254
1255=item *
1256
fcd5df6d
FR
1257C<Attribute::Handlers> has been upgraded from version 0.87 to 0.89.
1258
1259=item *
1260
3f5a47e4
FR
1261C<autodie> has been upgraded from version 2.06_01 to 2.1001.
1262
1263=item *
1264
578e7c9d
FR
1265C<AutoLoader> has been upgraded from version 5.70 to 5.71.
1266
1267=item *
1268
a13baafd 1269C<B> has been upgraded from version 1.23 to 1.29.
5076a392
FC
1270
1271It no longer crashes when taking apart a C<y///> containing characters
1272outside the octet range or compiled in a C<use utf8> scope.
1273
1274The size of the shared object has been reduced by about 40%, with no
1275reduction in functionality.
1276
1277=item *
1278
4a75fbf5 1279C<B::Concise> has been upgraded from version 0.78 to 0.83.
5076a392
FC
1280
1281B::Concise marks rv2sv, rv2av and rv2hv ops with the new OPpDEREF flag
1282as "DREFed".
1283
1284It no longer produces mangled output with the C<-tree> option
1285[perl #80632].
1286
1287=item *
1288
6bb8c1e3
FR
1289C<B::Debug> has been upgraded from version 1.12 to 1.16.
1290
1291=item *
1292
c67a4e29 1293C<B::Deparse> has been upgraded from version 0.96 to 1.03.
5076a392 1294
1984204c 1295The deparsing of a nextstate op has changed when it has both a
5076a392
FC
1296change of package (relative to the previous nextstate), or a change of
1297C<%^H> or other state, and a label. Previously the label was emitted
cdc10f43 1298first, but now the label is emitted last (5.12.1).
5076a392 1299
5a553547
FC
1300The C<no 5.13.2> or similar form is now correctly handled by B::Deparse
1301(5.12.3).
5076a392
FC
1302
1303B::Deparse now properly handles the code that applies a conditional
1304pattern match against implicit C<$_> as it was fixed in [perl #20444].
1305
1984204c
FC
1306Deparsing of C<our> followed by a variable with funny characters
1307(as permitted under the C<utf8> pragma) has also been fixed [perl #33752].
5076a392
FC
1308
1309=item *
1310
d97c5d3b
FR
1311C<B::Lint> has been upgraded from version 1.11_01 to 1.13.
1312
1313=item *
1314
5aef2c44
FR
1315C<base> has been upgraded from version 2.15 to 2.16.
1316
1317=item *
1318
876607aa
FR
1319C<Benchmark> has been upgraded from version 1.11 to 1.12.
1320
1321=item *
1322
0f3a8103 1323C<bignum> has been upgraded from version 0.23 to 0.27.
e539ae69
FR
1324
1325=item *
1326
c74c1fa8 1327C<Carp> has been upgraded from version 1.15 to 1.20.
5076a392
FC
1328
1329L<Carp> now detects incomplete L<caller()|perlfunc/"caller EXPR"> overrides and
d430b8e7
FC
1330avoids using bogus C<@DB::args>. To provide backtraces,
1331Carp relies on particular behaviour of the C<caller>
1332built-in. Carp now detects if other code has
5076a392 1333overridden this with an incomplete implementation, and modifies its backtrace
d430b8e7
FC
1334accordingly. Previously incomplete overrides would cause incorrect values
1335in backtraces (best case), or obscure fatal errors (worst case).
5076a392
FC
1336
1337This fixes certain cases of C<Bizarre copy of ARRAY> caused by modules
d430b8e7 1338overriding C<caller()> incorrectly (5.12.2).
5076a392 1339
1984204c 1340It now also avoids using regular expressions that cause perl to
5076a392
FC
1341load its Unicode tables, in order to avoid the 'BEGIN not safe after
1342errors' error that will ensue if there has been a syntax error
1343[perl #82854].
1344
1345=item *
1346
9eb7ad55 1347C<CGI> has been upgraded from version 3.48 to 3.52.
5076a392
FC
1348
1349This provides the following security fixes: the MIME boundary in
1984204c
FC
1350multipart_init is now random and the handling of
1351newlines embedded in header values has been improved.
5076a392
FC
1352
1353=item *
1354
5076a392
FC
1355C<Compress::Raw::Bzip2> has been upgraded from version 2.024 to 2.033.
1356
1984204c 1357It has been updated to use bzip2 1.0.6.
5076a392
FC
1358
1359=item *
1360
51090521
FR
1361C<Compress::Raw::Zlib> has been upgraded from version 2.024 to 2.033.
1362
1363=item *
1364
f75b7efc 1365C<CPAN> has been upgraded from version 1.94_56 to 1.9600.
1984204c
FC
1366
1367Major highlights:
5076a392
FC
1368
1369=over 4
1370
1984204c 1371=item * much less configuration dialog hassle
5076a392 1372
1984204c 1373=item * support for META/MYMETA.json
5076a392 1374
1984204c 1375=item * support for local::lib
5076a392 1376
1984204c 1377=item * support for HTTP::Tiny to reduce the dependency on ftp sites
5076a392 1378
1984204c 1379=item * automatic mirror selection
5076a392 1380
1984204c 1381=item * iron out all known bugs in configure_requires
5076a392 1382
1984204c
FC
1383=item * support for distributions compressed with bzip2
1384
1385=item * allow Foo/Bar.pm on the commandline to mean Foo::Bar
1386
1387=back
5076a392
FC
1388
1389=item *
1390
d430b8e7
FC
1391C<CPANPLUS> has been upgraded from version 0.90 to 0.9103.
1392
1393A change to F<cpanp-run-perl>
1394resolves L<RT #55964|http://rt.cpan.org/Public/Bug/Display.html?id=55964>
1395and L<RT #57106|http://rt.cpan.org/Public/Bug/Display.html?id=57106>, both
1396of which related to failures to install distributions that use
1397C<Module::Install::DSL> (5.12.2).
5076a392 1398
1984204c
FC
1399A dependency on Config was not recognised as a
1400core module dependency. This has been fixed.
5076a392 1401
1984204c 1402CPANPLUS now includes support for META.json and MYMETA.json.
5076a392
FC
1403
1404=item *
1405
4467e8f7
FR
1406C<CPANPLUS::Dist::Build> has been upgraded from version 0.46 to 0.54.
1407
1408=item *
1409
5076a392
FC
1410C<Data::Dumper> has been upgraded from version 2.125 to 2.130_02.
1411
4ed2cea4
FC
1412The indentation used to be off when C<$Data::Dumper::Terse> was set. This
1413has been fixed [perl #73604].
1414
1984204c
FC
1415This upgrade also fixes a crash when using custom sort functions that might
1416cause the stack to change [perl #74170].
5076a392
FC
1417
1418C<Dumpxs> no longer crashes with globs returned by C<*$io_ref>
1419[perl #72332].
1420
1421=item *
1422
549d34f5
FR
1423C<DB_File> has been upgraded from version 1.820 to 1.821.
1424
1425=item *
1426
851dbda2
FR
1427C<DBM_Filter> has been upgraded from version 0.03 to 0.04.
1428
1429=item *
1430
5076a392
FC
1431C<Devel::DProf> has been upgraded from version 20080331.00 to 20110228.00.
1432
1433Merely loading C<Devel::DProf> now no longer triggers profiling to start.
1434C<use Devel::DProf> and C<perl -d:DProf ...> still behave as before and start
1435the profiler.
1436
1437NOTE: C<Devel::DProf> is deprecated and will be removed from a future
1984204c 1438version of Perl. We strongly recommend that you install and use
5076a392
FC
1439L<Devel::NYTProf> instead, as it offers significantly improved
1440profiling and reporting.
1441
1442=item *
1443
868625d2
FR
1444C<Devel::Peek> has been upgraded from version 1.04 to 1.07.
1445
1446=item *
1447
66899ca3
FR
1448C<Devel::SelfStubber> has been upgraded from version 1.03 to 1.05.
1449
1450=item *
1451
5076a392
FC
1452C<diagnostics> has been upgraded from version 1.19 to 1.22.
1453
1454It now renders pod links slightly better, and has been taught to find
1455descriptions for messages that share their descriptions with other
1456messages.
1457
1458=item *
1459
1460C<Digest::MD5> has been upgraded from version 2.39 to 2.51.
1461
1462It is now safe to use this module in combination with threads.
1463
1464=item *
1465
1466C<Digest::SHA> has been upgraded from version 5.47 to 5.61.
1467
1468C<shasum> now more closely mimics C<sha1sum>/C<md5sum>.
1469
1470C<Addfile> accepts all POSIX filenames.
1471
1984204c
FC
1472New SHA-512/224 and SHA-512/256 transforms (ref. NIST Draft FIPS 180-4
1473[February 2011])
5076a392
FC
1474
1475=item *
1476
88410521
FR
1477C<DirHandle> has been upgraded from version 1.03 to 1.04.
1478
1479=item *
1480
e53cbaa3
FR
1481C<Dumpvalue> has been upgraded from version 1.13 to 1.16.
1482
1483=item *
1484
31e8b85a 1485C<DynaLoader> has been upgraded from version 1.10 to 1.13.
5076a392
FC
1486
1487It fixes a buffer overflow when passed a very long file name.
1488
1489It no longer inherits from AutoLoader; hence it no longer
1490produces weird error messages for unsuccessful method calls on classes that
1491inherit from DynaLoader [perl #84358].
1492
1493=item *
1494
1495C<Encode> has been upgraded from version 2.39 to 2.42.
1496
1497Now, all 66 Unicode non-characters are treated the same way U+FFFF has
1984204c
FC
1498always been treated; in cases when it was disallowed, all 66 are
1499disallowed; in those cases where it warned, all 66 warn.
5076a392
FC
1500
1501=item *
1502
68f90ac3
FR
1503C<Env> has been upgraded from version 1.01 to 1.02.
1504
1505=item *
1506
5076a392
FC
1507C<Errno> has been upgraded from version 1.11 to 1.13.
1508
1509The implementation of C<Errno> has been refactored to use about 55% less memory.
5076a392
FC
1510
1511On some platforms with unusual header files, like Win32/gcc using mingw64
1512headers, some constants which weren't actually error numbers have been exposed
1513by C<Errno>. This has been fixed [perl #77416].
1514
1515=item *
1516
1517C<Exporter> has been upgraded from version 5.64_01 to 5.64_03.
1518
1519Exporter no longer overrides C<$SIG{__WARN__}> [perl #74472]
1520
1521=item *
1522
25fe7f8f
FR
1523C<ExtUtils::CBuilder> has been upgraded from version 0.27 to 0.280202.
1524
1525=item *
1526
2292e71e
FR
1527C<ExtUtils::Command> has been upgraded from version 1.16 to 1.17.
1528
1529=item *
1530
5076a392
FC
1531C<ExtUtils::Constant> has been upgraded from 0.22 to 0.23.
1532
1533The C<AUTOLOAD> helper code generated by C<ExtUtils::Constant::ProxySubs>
1534can now C<croak> for missing constants, or generate a complete C<AUTOLOAD>
1984204c
FC
1535subroutine in XS, allowing simplification of many modules that use it
1536(C<Fcntl>, C<File::Glob>, C<GDBM_File>, C<I18N::Langinfo>, C<POSIX>,
1537C<Socket>).
5076a392
FC
1538
1539C<ExtUtils::Constant::ProxySubs> can now optionally push the names of all
1984204c 1540constants onto the package's C<@EXPORT_OK>.
5076a392
FC
1541
1542=item *
1543
588c5853
FR
1544C<ExtUtils::Install> has been upgraded from version 1.55 to 1.56.
1545
1546=item *
1547
5418ffb3
FR
1548C<ExtUtils::MakeMaker> has been upgraded from version 6.56 to 6.57_05.
1549
1550=item *
1551
f40ab45f
FR
1552C<ExtUtils::Manifest> has been upgraded from version 1.57 to 1.58.
1553
1554=item *
1555
10fb15d2 1556C<ExtUtils::ParseXS> has been upgraded from version 2.21 to 2.2210.
b7064dd7
FR
1557
1558=item *
1559
8b87be80 1560C<Fcntl> has been upgraded from version 1.06 to 1.11.
26f7fa64
FR
1561
1562=item *
1563
1564C<File::Basename> has been upgraded from version 2.78 to 2.81.
8b87be80
FR
1565
1566=item *
1567
05102622
FR
1568C<File::CheckTree> has been upgraded from version 4.4 to 4.41.
1569
1570=item *
1571
65d78858
FR
1572C<File::Copy> has been upgraded from version 2.17 to 2.21.
1573
1574=item *
1575
e12786fa 1576C<File::DosGlob> has been upgraded from version 1.01 to 1.04.
5076a392
FC
1577
1578It allows patterns containing literal parentheses (they no longer need to
1984204c
FC
1579be escaped). On Windows, it no longer
1580adds an extra F<./> to the file names
5076a392
FC
1581returned when the pattern is a relative glob with a drive specification,
1582like F<c:*.pl> [perl #71712].
1583
1584=item *
1585
1586C<File::Fetch> has been upgraded from version 0.24 to 0.32.
1587
1588C<HTTP::Lite> is now supported for 'http' scheme.
1589
1590The C<fetch> utility is supported on FreeBSD, NetBSD and
1591Dragonfly BSD for the C<http> and C<ftp> schemes.
1592
1593=item *
1594
23f2cbb1 1595C<File::Find> has been upgraded from version 1.15 to 1.19.
5076a392 1596
1984204c 1597It improves handling of backslashes on Windows, so that paths like
5076a392
FC
1598F<c:\dir\/file> are no longer generated [perl #71710].
1599
1600=item *
1601
0ae9f678
FR
1602C<File::Glob> has been upgraded from version 1.07 to 1.12.
1603
1604=item *
1605
d430b8e7
FC
1606C<File::Spec> has been upgraded from version 3.31 to 3.33.
1607
1608Several portability fixes were made in C<File::Spec::VMS>: a colon is now
1609recognized as a delimiter in native filespecs; caret-escaped delimiters are
1610recognized for better handling of extended filespecs; C<catpath()> returns
1611an empty directory rather than the current directory if the input directory
1612name is empty; C<abs2rel()> properly handles Unix-style input (5.12.2).
1613
1614=item *
1615
46ba0657 1616C<File::stat> has been upgraded from 1.02 to 1.05.
5076a392
FC
1617
1618The C<-x> and C<-X> file test operators now work correctly under the root
1619user.
1620
1621=item *
1622
b7edcc3c
FR
1623C<Filter::Simple> has been upgraded from version 0.84 to 0.86.
1624
1625=item *
1626
dc6857fd 1627C<GDBM_File> has been upgraded from 1.10 to 1.14.
5076a392
FC
1628
1629This fixes a memory leak when DBM filters are used.
1630
1631=item *
1632
6e107b45 1633C<Hash::Util> has been upgraded from 0.07 to 0.11.
5076a392 1634
1984204c
FC
1635Hash::Util no longer emits spurious "uninitialized" warnings when
1636recursively locking hashes that have undefined values [perl #74280].
5076a392
FC
1637
1638=item *
1639
89ce9b34
FR
1640C<Hash::Util::FieldHash> has been upgraded from version 1.04 to 1.09.
1641
1642=item *
1643
eec33fe6
FR
1644C<I18N::Collate> has been upgraded from version 1.01 to 1.02.
1645
1646=item *
1647
ad5f8f47 1648C<I18N::Langinfo> has been upgraded from version 0.03 to 0.08.
5076a392
FC
1649
1650C<langinfo()> now defaults to using C<$_> if there is no argument given, just
5334145a 1651as the documentation has always claimed.
5076a392
FC
1652
1653=item *
1654
c41635f7
FR
1655C<I18N::LangTags> has been upgraded from version 0.35 to 0.35_01.
1656
1657=item *
1658
98a6a4ff
FR
1659C<if> has been upgraded from version 0.05 to 0.0601.
1660
1661=item *
1662
f6ff7fb6
FR
1663C<IO> has been upgraded from version 1.25_02 to 1.25_04.
1664
582bf58c
FR
1665This version of C<IO> includes a new C<IO::Select>, which now allows IO::Handle
1666objects (and objects in derived classes) to be removed from an IO::Select set
1667even if the underlying file descriptor is closed or invalid.
5076a392
FC
1668
1669=item *
1670
d07561d3 1671C<IPC::Cmd> has been upgraded from version 0.54 to 0.70.
5076a392 1672
1984204c
FC
1673Resolves an issue with splitting Win32 command lines. An argument
1674consisting of the single character "0" used to be omitted (CPAN RT #62961).
5076a392
FC
1675
1676=item *
1677
3f16e4eb 1678C<IPC::Open3> has been upgraded from 1.05 to 1.09.
5076a392 1679
4ed2cea4
FC
1680C<open3> now produces an error if the C<exec> call fails, allowing this
1681condition to be distinguished from a child process that exited with a
1682non-zero status [perl #72016].
1683
5076a392
FC
1684The internal C<xclose> routine now knows how to handle file descriptors, as
1685documented, so duplicating STDIN in a child process using its file
1686descriptor now works [perl #76474].
1687
1688=item *
1689
c8b41807
FR
1690C<IPC::SysV> has been upgraded from version 2.01 to 2.03.
1691
1692=item *
1693
ef79f038
FR
1694C<lib> has been upgraded from version 0.62 to 0.63.
1695
1696=item *
1697
5b1884f4 1698C<Locale::Maketext> has been upgraded from version 1.14 to 1.19.
5076a392 1699
1984204c 1700Locale::Maketext now supports external caches.
5076a392 1701
1984204c
FC
1702This upgrade also fixes an infinite loop in
1703C<Locale::Maketext::Guts::_compile()> when
5076a392
FC
1704working with tainted values (CPAN RT #40727).
1705
1984204c 1706C<< ->maketext >> calls will now back up and restore C<$@> so that error
5076a392
FC
1707messages are not suppressed (CPAN RT #34182).
1708
1709=item *
1710
3811bd2b
FR
1711C<Log::Message> has been upgraded from version 0.02 to 0.04.
1712
1713=item *
1714
8eb65377
FR
1715C<Log::Message::Simple> has been upgraded from version 0.06 to 0.08.
1716
1717=item *
1718
5076a392
FC
1719C<Math::BigInt> has been upgraded from version 1.89_01 to 1.994.
1720
1721This fixes, among other things, incorrect results when computing binomial
1722coefficients [perl #77640].
1723
1984204c 1724It also prevents C<sqrt($int)> from crashing under C<use bigrat;>
5076a392
FC
1725[perl #73534].
1726
1727=item *
1728
846c1cec
FR
1729C<Math::BigInt::FastCalc> has been upgraded from version 0.19 to 0.28.
1730
1731=item *
1732
fce4aef3
FR
1733C<Math::BigRat> has been upgraded from version 0.24 to 0.26_02.
1734
1735=item *
1736
12e26027
FR
1737C<Memoize> has been upgraded from version 1.01_03 to 1.02.
1738
1739=item *
1740
5076a392
FC
1741C<MIME::Base64> has been upgraded from 3.08 to 3.13.
1742
1743Includes new functions to calculate the length of encoded and decoded
1744base64 strings.
1745
1746Now provides C<encode_base64url> and C<decode_base64url> functions to process
1747the base64 scheme for "URL applications".
1748
1749=item *
1750
1751C<Module::Build> has been upgraded from version 0.3603 to 0.3800.
1752
1753A notable change is the deprecation of several modules.
1754Module::Build::Version has been deprecated and Module::Build now relies
1755directly upon L<version>. Module::Build::ModuleInfo has been deprecated in
1756favor of a standalone copy of it called L<Module::Metadata>.
1757Module::Build::YAML has been deprecated in favor of L<CPAN::Meta::YAML>.
1758
1759Module::Build now also generates META.json and MYMETA.json files
1760in accordance with version 2 of the CPAN distribution metadata specification,
1761L<CPAN::Meta::Spec>. The older format META.yml and MYMETA.yml files are
1762still generated, as well.
1763
1764=item *
1765
7259fe26 1766C<Module::CoreList> has been upgraded from version 2.29 to 2.47.
5076a392
FC
1767
1768Besides listing the updated core modules of this release, it also stops listing
1984204c 1769the C<Filespec> module. That module never existed in core. The scripts
5076a392 1770generating C<Module::CoreList> confused it with C<VMS::Filespec>, which actually
1984204c 1771is a core module as of perl 5.8.7.
5076a392
FC
1772
1773=item *
1774
193af05b
FR
1775C<Module::Load> has been upgraded from version 0.16 to 0.18.
1776
1777=item *
1778
5b3a054f
FR
1779C<Module::Load::Conditional> has been upgraded from version 0.34 to 0.44.
1780
1781=item *
1782
01835e3a
FR
1783C<mro> has been upgraded from version 1.02 to 1.07.
1784
1785=item *
1786
bfe7bf96 1787C<NDBM_File> has been upgraded from version 1.08 to 1.12.
4f978a3b
FR
1788
1789This fixes a memory leak when DBM filters are used.
1790
1791=item *
1792
d0aa5c91
FR
1793C<Net::Ping> has been upgraded from version 2.36 to 2.38.
1794
1795=item *
1796
d44b8a8c
FR
1797C<NEXT> has been upgraded from version 0.64 to 0.65.
1798
1799=item *
1800
678d4fd4
FR
1801C<Object::Accessor> has been upgraded from version 0.36 to 0.38.
1802
1803=item *
1804
34188656 1805C<ODBM_File> have been upgraded from version 1.07 to 1.10.
5076a392
FC
1806
1807This fixes a memory leak when DBM filters are used.
1808
1809=item *
1810
4c69840c
FR
1811C<Opcode> has been upgraded from version 1.15 to 1.18.
1812
1813=item *
1814
f4c5ae54 1815C<overload> has been upgraded from 1.10 to 1.13.
5076a392
FC
1816
1817C<overload::Method> can now handle subroutines that are themselves blessed
1818into overloaded classes [perl #71998].
1819
5076a392
FC
1820The documentation has greatly improved. See L</Documentation> below.
1821
1822=item *
1823
f84c796e
FR
1824C<Params::Check> has been upgraded from version 0.26 to 0.28.
1825
1826=item *
1827
550ee92b
FR
1828C<parent> has been upgraded from version 0.223 to 0.225.
1829
1830=item *
1831
5076a392
FC
1832C<Parse::CPAN::Meta> has been upgraded from version 1.40 to 1.4401.
1833
1984204c 1834The latest Parse::CPAN::Meta can now read YAML and JSON files using
5076a392
FC
1835L<CPAN::Meta::YAML> and L<JSON::PP>, which are now part of the Perl core.
1836
1837=item *
1838
e981cf86
FR
1839C<PerlIO::encoding> has been upgraded from version 0.12 to 0.14.
1840
1841=item *
1842
5076a392
FC
1843C<PerlIO::scalar> has been upgraded from 0.07 to 0.11.
1844
1845A C<read> after a C<seek> beyond the end of the string no longer thinks it
1846has data to read [perl #78716].
1847
1848=item *
1849
776f733b
FR
1850C<PerlIO::via> has been upgraded from version 0.09 to 0.11.
1851
1852=item *
1853
cb1db9bd 1854C<Pod::Html> has been upgraded from version 1.09 to 1.11.
ae9456cc
FR
1855
1856=item *
1857
be3c8498
FR
1858C<Pod::LaTeX> has been upgraded from version 0.58 to 0.59.
1859
1860=item *
1861
fd8a2e89
FR
1862C<Pod::Perldoc> has been upgraded from version 3.15_02 to 3.15_03.
1863
1864=item *
1865
5bcb6583
FR
1866C<Pod::Simple> has been upgraded from version 3.13 to 3.16.
1867
1868=item *
1869
abb8c779 1870C<POSIX> has been upgraded from 1.19 to 1.24.
5076a392
FC
1871
1872It now includes constants for POSIX signal constants.
1873
1874=item *
1875
1984204c 1876C<re> has been upgraded from version 0.11 to 0.17.
5076a392
FC
1877
1878New C<use re "/flags"> pragma
1879
5076a392 1880The C<regmust> function used to crash when called on a regular expression
1984204c 1881belonging to a pluggable engine. Now it croaks instead.
5076a392
FC
1882
1883C<regmust> no longer leaks memory.
1884
1885=item *
1886
1887C<Safe> has been upgraded from version 2.25 to 2.29.
1888
cdc10f43
FC
1889Coderefs returned by C<reval()> and C<rdo()> are now wrapped via
1890C<wrap_code_refs> (5.12.1).
1891
5076a392
FC
1892This fixes a possible infinite loop when looking for coderefs.
1893
cdc10f43 1894It adds several version::vxs::* routines to the default share.
5076a392
FC
1895
1896=item *
1897
2c19fa42
FR
1898C<SDBM_File> has been upgraded from version 1.06 to 1.09.
1899
1900=item *
1901
5076a392
FC
1902C<SelfLoader> has been upgraded from 1.17 to 1.18.
1903
1904It now works in taint mode [perl #72062].
1905
1906=item *
1907
1908C<sigtrap> has been upgraded from version 1.04 to 1.05.
1909
1910It no longer tries to modify read-only arguments when generating a
1911backtrace [perl #72340].
1912
1913=item *
1914
1984204c 1915C<Socket> has been upgraded from version 1.87 to 1.94.
5076a392 1916
1984204c 1917See L</IPv6 support>, above.
5076a392
FC
1918
1919=item *
1920
1921C<Storable> has been upgraded from version 2.22 to 2.27.
1922
1923Includes performance improvement for overloaded classes.
1924
5076a392 1925This adds support for serialising code references that contain UTF-8 strings
1984204c
FC
1926correctly. The Storable minor version
1927number changed as a result, meaning that
5076a392
FC
1928Storable users who set C<$Storable::accept_future_minor> to a C<FALSE> value
1929will see errors (see L<Storable/FORWARD COMPATIBILITY> for more details).
1930
1931Freezing no longer gets confused if the Perl stack gets reallocated
1932during freezing [perl #80074].
1933
1934=item *
1935
648c3d7d
FR
1936C<Sys::Hostname> has been upgraded from version 1.11 to 1.16.
1937
1938=item *
1939
90c6e78f
FR
1940C<Term::ANSIColor> has been upgraded from version 2.02 to 3.00.
1941
1942=item *
1943
d9f2f059
FR
1944C<Term::UI> has been upgraded from version 0.20 to 0.26.
1945
1946=item *
1947
80ebb519
FR
1948C<Test::Harness> has been upgraded from version 3.17 to 3.23.
1949
1950=item *
1951
5076a392
FC
1952C<Test::Simple> has been upgraded from version 0.94 to 0.98.
1953
1954Among many other things, subtests without a C<plan> or C<no_plan> now have an
1955implicit C<done_testing()> added to them.
1956
1957=item *
1958
5076a392
FC
1959C<Thread::Semaphore> has been upgraded from version 2.09 to 2.12.
1960
1984204c
FC
1961It provides two new methods that give more control over the decrementing of
1962semaphores: C<down_nb> and C<down_force>.
5076a392
FC
1963
1964=item *
1965
f0d895e1
FR
1966C<Thread::Queue> has been upgraded from version 2.11 to 2.12.
1967
1968=item *
1969
1a6b954e
FR
1970C<threads> has been upgraded from version 1.75 to 1.83.
1971
1972=item *
1973
55816daa
FR
1974C<threads::shared> has been upgraded from version 1.32 to 1.36.
1975
1976=item *
1977
5076a392
FC
1978C<Tie::Hash> has been upgraded from version 1.03 to 1.04.
1979
1980Calling C<< Tie::Hash-E<gt>TIEHASH() >> used to loop forever. Now it C<croak>s.
1981
1982=item *
1983
f2adc546
FR
1984C<Tie::Hash::NamedCapture> has been upgraded from version 0.06 to 0.08.
1985
1986=item *
1987
ed68b07e
FR
1988C<Tie::RefHash> has been upgraded from version 1.38 to 1.39.
1989
1990=item *
1991
bb3c221a
FR
1992C<Time::HiRes> has been upgraded from version 1.9719 to 1.9721_01.
1993
1994=item *
1995
97fa568b
FR
1996C<Time::Local> has been upgraded from version 1.1901_01 to 1.2000.
1997
1998=item *
1999
a83cb732
FR
2000C<Time::Piece> has been upgraded from version 1.15_01 to 1.20_01.
2001
2002=item *
2003
5076a392
FC
2004C<Unicode::Collate> has been upgraded from version 0.52_01 to 0.73.
2005
1984204c 2006Unicode::Collate has been updated to use Unicode 6.0.0.
5076a392 2007
1984204c
FC
2008Unicode::Collate::Locale now supports a plethora of new locales: ar, be,
2009bg, de__phonebook, hu, hy, kk, mk, nso, om, tn, vi, hr, ig, ja, ko, ru, sq,
2010se, sr, to, uk, zh, zh__big5han, zh__gb2312han, zh__pinyin and zh__stroke.
5076a392
FC
2011
2012The following modules have been added:
2013
2014C<Unicode::Collate::CJK::Big5> for C<zh__big5han> which makes
2015tailoring of CJK Unified Ideographs in the order of CLDR's big5han ordering.
2016
2017C<Unicode::Collate::CJK::GB2312> for C<zh__gb2312han> which makes
2018tailoring of CJK Unified Ideographs in the order of CLDR's gb2312han ordering.
2019
2020C<Unicode::Collate::CJK::JISX0208> which makes tailoring of 6355 kanji
2021(CJK Unified Ideographs) in the JIS X 0208 order.
2022
2023C<Unicode::Collate::CJK::Korean> which makes tailoring of CJK Unified Ideographs
2024in the order of CLDR's Korean ordering.
2025
2026C<Unicode::Collate::CJK::Pinyin> for C<zh__pinyin> which makes
2027tailoring of CJK Unified Ideographs in the order of CLDR's pinyin ordering.
2028
2029C<Unicode::Collate::CJK::Stroke> for C<zh__stroke> which makes
2030tailoring of CJK Unified Ideographs in the order of CLDR's stroke ordering.
2031
5076a392
FC
2032This also sees the switch from using the pure-perl version of this
2033module to the XS version.
2034
2035=item *
2036
ec52b54b
FR
2037C<Unicode::Normalize> has been upgraded from version 1.03 to 1.10.
2038
2039=item *
2040
5076a392
FC
2041C<Unicode::UCD> has been upgraded from version 0.27 to 0.32.
2042
1984204c
FC
2043A new function, C<Unicode::UCD::num()>, has been added. This function
2044returns the numeric value of the string passed it or C<undef> if the string
2045in its entirety has no "safe" numeric value. (For more detail, and for the
2046definition of "safe", see L<Unicode::UCD/num>.)
5076a392 2047
1984204c 2048This upgrade also includes a number of bug fixes:
5076a392
FC
2049
2050=over 4
2051
2052=item charinfo()
2053
2054=over 4
2055
2056=item *
2057
2058It is now updated to Unicode Version 6 with Corrigendum #8, except,
2059as with Perl 5.14, the code point at U+1F514 has no name.
2060
2061=item *
2062
2063The Hangul syllable code points have the correct names, and their
2064decompositions are always output without requiring L<Lingua::KO::Hangul::Util>
2065to be installed.
2066
2067=item *
2068
54c7bb16
FC
2069The CJK (Chinese-Japanese-Korean) code points U+2A700 to U+2B734
2070and U+2B740 to U+2B81D are now properly handled.
5076a392
FC
2071
2072=item *
2073
2074The numeric values are now output for those CJK code points that have them.
2075
2076=item *
2077
2078The names that are output for code points with multiple aliases are now the
2079corrected ones.
2080
2081=back
2082
2083=item charscript()
2084
2085This now correctly returns "Unknown" instead of C<undef> for the script
2086of a code point that hasn't been assigned another one.
2087
2088=item charblock()
2089
2090This now correctly returns "No_Block" instead of C<undef> for the block
2091of a code point that hasn't been assigned to another one.
2092
2093=back
2094
5076a392
FC
2095=item *
2096
2097C<version> has been upgraded from 0.82 to 0.88.
2098
1984204c 2099Due to a bug, now fixed, the C<is_strict> and C<is_lax> functions did not
cdc10f43 2100work when exported (5.12.1).
5076a392
FC
2101
2102=item *
2103
3e625598 2104C<warnings> has been upgraded from version 1.09 to 1.12.
5076a392
FC
2105
2106Calling C<use warnings> without arguments is now significantly more efficient.
2107
4f978a3b
FR
2108=item *
2109
2110C<warnings::register> have been upgraded from version 1.01 to 1.02.
2111
5076a392
FC
2112It is now possible to register warning categories other than the names of
2113packages using C<warnings::register>. See L<perllexwarn> for more information.
2114
2115=item *
2116
62e270c2
FR
2117C<XSLoader> has been upgraded from version 0.10 to 0.13.
2118
2119=item *
2120
5076a392
FC
2121C<VMS::DCLsym> has been upgraded from version 1.03 to 1.05.
2122
2123Two bugs have been fixed [perl #84086]:
2124
2125The symbol table name was lost when tying a hash, due to a thinko in
2126C<TIEHASH>. The result was that all tied hashes interacted with the
2127local symbol table.
2128
2129Unless a symbol table name had been explicitly specified in the call
2130to the constructor, querying the special key ':LOCAL' failed to
2131identify objects connected to the local symbol table.
2132
2133=item *
2134
2135C<Win32> has been upgraded from version 0.39 to 0.44.
2136
1984204c
FC
2137This release has several new functions: C<Win32::GetSystemMetrics>,
2138C<Win32::GetProductInfo>, C<Win32::GetOSDisplayName>.
5076a392 2139
1984204c
FC
2140The names returned by C<Win32::GetOSName> and C<Win32::GetOSDisplayName>
2141have been corrected.
5076a392 2142
3bbe5383
FR
2143=item *
2144
2145C<XS::Typemap> has been upgraded from version 0.03 to 0.05.
2146
5076a392
FC
2147=back
2148
5076a392
FC
2149=head2 Removed Modules and Pragmata
2150
2151The following modules have been removed from the core distribution, and if
2152needed should be installed from CPAN instead.
2153
2154=over
2155
4f978a3b
FR
2156=item *
2157
2158C<Class::ISA> has been removed from the Perl core. Prior version was 0.36.
5076a392 2159
4f978a3b
FR
2160=item *
2161
2162C<Pod::Plainer> has been removed from the Perl core. Prior version was 1.02.
2163
2164=item *
5076a392 2165
4f978a3b 2166C<Switch> has been removed from the Perl core. Prior version was 2.16.
5076a392
FC
2167
2168=back
2169
2170The removal of C<Shell> has been deferred until after 5.14, as the
2171implementation of C<Shell> shipped with 5.12.0 did not correctly issue the
2172warning that it was to be removed from core.
2173
2174=head1 Documentation
2175
5076a392
FC
2176=head2 New Documentation
2177
41e29def 2178=head3 L<perlgpl>
5076a392
FC
2179
2180L<perlgpl> has been updated to contain GPL version 1, as is included in the
cdc10f43 2181F<README> distributed with perl (5.12.1).
5076a392 2182
41e29def 2183=head3 Perl 5.12.x delta files
5076a392 2184
41e29def
FC
2185The perldelta files for Perl 5.12.1 to 5.12.3 have been added from the
2186maintenance branch: L<perl5121delta>, L<perl5122delta>, L<perl5123delta>.
5076a392
FC
2187
2188=head3 L<perlpodstyle>
2189
2190New style guide for POD documentation,
2191split mostly from the NOTES section of the pod2man man page.
2192
41e29def
FC
2193=head3 L<perlsource>, L<perlinterp>, L<perlhacktut>, and L<perlhacktips>
2194
cc13eef1 2195See L</perlhack and perlrepository revamp>, below.
5076a392
FC
2196
2197=head2 Changes to Existing Documentation
2198
41e29def 2199=head3 L<perlmodlib> is now complete
4ed2cea4
FC
2200
2201The perlmodlib page that came with Perl 5.12.0 was missing a lot of
a60ea503 2202modules, due to a bug in the script that generates the list. This has been
cdc10f43 2203fixed [perl #74332] (5.12.1).
4ed2cea4 2204
41e29def 2205=head3 Replace wrong tr/// table in L<perlebcdic>
5076a392 2206
41e29def 2207L<perlebcdic> contains a helpful table to use in tr/// to convert
5076a392
FC
2208between EBCDIC and Latin1/ASCII. Unfortunately, the table was the
2209inverse of the one it describes, though the code that used the table
2210worked correctly for the specific example given.
2211
2212The table has been changed to its inverse, and the sample code changed
2213to correspond, as this is easier for the person trying to follow the
2214instructions since deriving the old table is somewhat more complicated.
2215
2216The table has also been changed to hex from octal, as that is more the norm
2217these days, and the recipes in the pod altered to print out leading
41e29def 2218zeros to make all the values the same length.
5076a392 2219
41e29def 2220=head3 Tricks for user-defined casing
5076a392 2221
41e29def
FC
2222L<perlunicode> now contains an explanation of how to override, mangle
2223and otherwise tweak the way perl handles upper-, lower- and other-case
2224conversions on Unicode data, and how to provide scoped changes to alter
2225one's own code's behaviour without stomping on anybody else.
5076a392
FC
2226
2227=head3 INSTALL explicitly states the requirement for C89
2228
d430b8e7
FC
2229This was already true but it's now Officially Stated For The Record
2230(5.12.2).
5076a392 2231
41e29def 2232=head3 Explanation of C<\xI<HH>> and C<\oI<OOO>> escapes
5076a392 2233
41e29def
FC
2234L<perlop> has been updated with more detailed explanation of these two
2235character escapes.
5076a392 2236
41e29def 2237=head3 C<-0I<NNN>> switch
5076a392 2238
41e29def 2239In L<perlrun>, the behavior of the C<-0NNN> switch for C<-0400> or higher
d430b8e7 2240has been clarified (5.12.2).
5076a392 2241
cdc10f43
FC
2242=head3 Maintenance policy
2243
2244L<perlpolicy> now contains the policy on what patches are acceptable for
2245maintenance branches (5.12.1).
2246
41e29def 2247=head3 Deprecation policy
5076a392 2248
41e29def 2249L<perlpolicy> now contains the policy on compatibility and deprecation
d430b8e7 2250along with definitions of terms like "deprecation" (5.12.2).
5076a392 2251
41e29def 2252=head3 New descriptions in L<perldiag>
5076a392
FC
2253
2254The following existing diagnostics are now documented:
2255
2256=over 4
2257
2258=item *
2259
2260L<Ambiguous use of %c resolved as operator %c|perldiag/"Ambiguous use of %c resolved as operator %c">
2261
2262=item *
2263
2264L<Ambiguous use of %c{%s} resolved to %c%s|perldiag/"Ambiguous use of %c{%s} resolved to %c%s">
2265
2266=item *
2267
2268L<Ambiguous use of %c{%s%s} resolved to %c%s%s|perldiag/"Ambiguous use of %c{%s%s} resolved to %c%s%s">
2269
2270=item *
2271
2272L<Ambiguous use of -%s resolved as -&%s()|perldiag/"Ambiguous use of -%s resolved as -&%s()">
2273
2274=item *
2275
2276L<Invalid strict version format (%s)|perldiag/"Invalid strict version format (%s)">
2277
2278=item *
2279
2280L<Invalid version format (%s)|perldiag/"Invalid version format (%s)">
2281
2282=item *
2283
2284L<Invalid version object|perldiag/"Invalid version object">
2285
2286=back
2287
5076a392
FC
2288=head3 L<perlbook>
2289
41e29def 2290L<perlbook> has been expanded to cover many more popular books.
5076a392 2291
41e29def 2292=head3 C<SvTRUE> macro
5076a392 2293
41e29def
FC
2294The documentation for the C<SvTRUE> macro in
2295L<perlapi> was simply wrong in stating that
a60ea503 2296get-magic is not processed. It has been corrected.
5076a392 2297
41e29def 2298=head3 L<perlvar> revamp
5076a392 2299
41e29def 2300L<perlvar> reorders the variables and groups them by topic. Each variable
5076a392 2301introduced after Perl 5.000 notes the first version in which it is
41e29def 2302available. L<perlvar> also has a new section for deprecated variables to
5076a392
FC
2303note when they were removed.
2304
41e29def 2305=head3 Array and hash slices in scalar context
5076a392 2306
41e29def 2307These are now documented in L<perldata>.
5076a392 2308
41e29def 2309=head3 C<use locale> and formats
5076a392
FC
2310
2311L<perlform> and L<perllocale> have been corrected to state that
2312C<use locale> affects formats.
2313
5076a392
FC
2314=head3 L<overload>
2315
a60ea503 2316L<overload>'s documentation has practically undergone a rewrite. It
5076a392
FC
2317is now much more straightforward and clear.
2318
cc13eef1 2319=head3 perlhack and perlrepository revamp
5076a392
FC
2320
2321The L<perlhack> and perlrepository documents have been heavily edited and
2322split up into several new documents.
2323
2324The L<perlhack> document is now much shorter, and focuses on the Perl 5
a60ea503
FC
2325development process and submitting patches
2326to Perl. The technical content has
5076a392 2327been moved to several new documents, L<perlsource>, L<perlinterp>,
a60ea503 2328L<perlhacktut>, and L<perlhacktips>. This technical content has only been
5076a392
FC
2329lightly edited.
2330
a60ea503
FC
2331The perlrepository document has been renamed to
2332L<perlgit>. This new document is just a how-to
2333on using git with the Perl source code. Any other content
5076a392
FC
2334that used to be in perlrepository has been moved to perlhack.
2335
41e29def 2336=head3 Time::Piece examples
5076a392
FC
2337
2338Examples in L<perlfaq4> have been updated to show the use of
41e29def 2339L<Time::Piece>.
5076a392
FC
2340
2341=head1 Diagnostics
2342
2343The following additions or changes have been made to diagnostic output,
2344including warnings and fatal error messages. For the complete list of
2345diagnostic messages, see L<perldiag>.
2346
2347=head2 New Diagnostics
2348
a593b319
FC
2349=head3 New Errors
2350
5076a392
FC
2351=over
2352
a593b319 2353=item Closure prototype called
5076a392 2354
a593b319
FC
2355This error occurs when a subroutine reference passed to an attribute
2356handler is called, if the subroutine is a closure [perl #68560].
5076a392 2357
a593b319 2358=item Insecure user-defined property %s
5076a392 2359
a593b319
FC
2360Perl detected tainted data when trying to compile a regular
2361expression that contains a call to a user-defined character property
2362function, i.e. C<\p{IsFoo}> or C<\p{InFoo}>.
2363See L<perlunicode/User-Defined Character Properties> and L<perlsec>.
5076a392 2364
a593b319 2365=item panic: gp_free failed to free glob pointer - something is repeatedly re-creating entries
5076a392 2366
a593b319
FC
2367This new error is triggered if a destructor called on an object in a
2368typeglob that is being freed creates a new typeglob entry containing an
2369object with a destructor that creates a new entry containing an object....
5076a392 2370
a593b319 2371=item Parsing code internal error (%s)
5076a392 2372
a593b319
FC
2373This new fatal error is produced when parsing
2374code supplied by an extension violates the
2375parser's API in a detectable way.
5076a392 2376
a593b319 2377=item refcnt: fd %d%s
5076a392 2378
a593b319
FC
2379This new error only occurs if a internal consistency check fails when a
2380pipe is about to be closed.
5076a392 2381
a593b319 2382=item Regexp modifier "/%c" may not appear twice
5076a392 2383
a593b319
FC
2384The regular expression pattern has one of the
2385mutually exclusive modifiers repeated.
5076a392 2386
a593b319 2387=item Regexp modifiers "/%c" and "/%c" are mutually exclusive
5076a392 2388
a593b319
FC
2389The regular expression pattern has more than one of the mutually
2390exclusive modifiers.
5076a392 2391
a593b319 2392=item Using !~ with %s doesn't make sense
5076a392 2393
a593b319 2394This error occurs when C<!~> is used with C<s///r> or C<y///r>.
5076a392 2395
a593b319 2396=back
5076a392 2397
a593b319 2398=head3 New Warnings
5076a392 2399
a593b319 2400=over
5076a392 2401
a593b319 2402=item "\b{" is deprecated; use "\b\{" instead
5076a392 2403
a593b319 2404=item "\B{" is deprecated; use "\B\{" instead
5076a392 2405
a593b319
FC
2406Use of an unescaped "{" immediately following a C<\b> or C<\B> is now
2407deprecated so as to reserve its use for Perl itself in a future release.
5076a392 2408
a593b319 2409=item Operation "%s" returns its argument for ...
5076a392 2410
a593b319 2411Performing an operation requiring Unicode semantics (such as case-folding)
a60ea503
FC
2412on a Unicode surrogate or a non-Unicode character now triggers this
2413warning.
5076a392 2414
a593b319
FC
2415=item Use of qw(...) as parentheses is deprecated
2416
2417See L</"Use of qw(...) as parentheses">, above, for details.
5076a392
FC
2418
2419=back
2420
2421=head2 Changes to Existing Diagnostics
2422
2423=over 4
2424
2425=item *
2426
4ed2cea4
FC
2427The "Variable $foo is not imported" warning that precedes a
2428C<strict 'vars'> error has now been assigned the "misc" category, so that
2429C<no warnings> will suppress it [perl #73712].
2430
2431=item *
2432
5076a392
FC
2433C<warn> and C<die> now produce 'Wide character' warnings when fed a
2434character outside the byte range if STDERR is a byte-sized handle.
2435
2436=item *
2437
2438The 'Layer does not match this perl' error message has been replaced with
a593b319 2439these more helpful messages [perl #73754]:
5076a392
FC
2440
2441=over 4
2442
2443=item *
2444
2445PerlIO layer function table size (%d) does not match size expected by this
2446perl (%d)
2447
2448=item *
2449
2450PerlIO layer instance size (%d) does not match size expected by this perl
2451(%d)
2452
2453=back
2454
5076a392
FC
2455=item *
2456
2457The "Found = in conditional" warning that is emitted when a constant is
2458assigned to a variable in a condition is now withheld if the constant is
2459actually a subroutine or one generated by C<use constant>, since the value
2460of the constant may not be known at the time the program is written
2461[perl #77762].
2462
2463=item *
2464
2465Previously, if none of the C<gethostbyaddr>, C<gethostbyname> and
2466C<gethostent> functions were implemented on a given platform, they would
2467all die with the message 'Unsupported socket function "gethostent" called',
2468with analogous messages for C<getnet*> and C<getserv*>. This has been
2469corrected.
2470
2471=item *
2472
a593b319
FC
2473The warning message about unrecognized regular expression escapes passed
2474through has been changed to include any literal '{' following the
2475two-character escape. E.g., "\q{" is now emitted instead of "\q".
5076a392
FC
2476
2477=back
2478
2479=head1 Utility Changes
2480
0b88cc74 2481=head3 L<perlbug>
5076a392
FC
2482
2483=over 4
2484
2485=item *
2486
0b88cc74
FC
2487L<perlbug> now looks in the EMAIL environment variable for a return address
2488if the REPLY-TO and REPLYTO variables are empty.
5076a392
FC
2489
2490=item *
2491
0b88cc74
FC
2492L<perlbug> did not previously generate a From: header, potentially
2493resulting in dropped mail. Now it does include that header.
5076a392
FC
2494
2495=item *
2496
0b88cc74 2497The user's address is now used as the return-path.
4ed2cea4 2498
0b88cc74
FC
2499Many systems these days don't have a valid Internet domain name and
2500perlbug@perl.org does not accept email with a return-path that does
2501not resolve. So the user's address is now passed to sendmail so it's
2502less likely to get stuck in a mail queue somewhere [perl #82996].
5076a392 2503
2c389f6c
FC
2504=item *
2505
d430b8e7
FC
2506L<perlbug> now always gives the reporter a chance to change the email
2507address it guesses for them (5.12.2).
2508
2509=item *
2510
2511L<perlbug> should no longer warn about uninitialized values when using the C<-d>
2512and C<-v> options (5.12.2).
2c389f6c 2513
5076a392
FC
2514=back
2515
0b88cc74 2516=head3 L<perl5db.pl>
5076a392 2517
0b88cc74 2518=over
5076a392
FC
2519
2520=item *
2521
0b88cc74
FC
2522The remote terminal works after forking and spawns new sessions - one
2523for each forked process.
5076a392
FC
2524
2525=back
2526
0b88cc74 2527=head3 L<ptargrep>
5076a392
FC
2528
2529=over 4
2530
2531=item *
2532
0b88cc74
FC
2533L<ptargrep> is a new utility to apply pattern matching to the contents of
2534files in a tar archive. It comes with C<Archive::Tar>.
5076a392
FC
2535
2536=back
2537
2538=head1 Configuration and Compilation
2539
61752d82
FC
2540See also L</"Naming fixes in Policy_sh.SH may invalidate Policy.sh">,
2541above.
2542
5076a392
FC
2543=over 4
2544
2545=item *
2546
87595b22
FC
2547CCINCDIR and CCLIBDIR for the mingw64
2548cross-compiler are now correctly under
5076a392
FC
2549$(CCHOME)\mingw\include and \lib rather than immediately below $(CCHOME).
2550
5076a392
FC
2551This means the 'incpath', 'libpth', 'ldflags', 'lddlflags' and
2552'ldflags_nolargefiles' values in Config.pm and Config_heavy.pl are now
87595b22 2553set correctly.
5076a392
FC
2554
2555=item *
2556
87595b22
FC
2557'make test.valgrind' has been adjusted to account for cpan/dist/ext
2558separation.
5076a392
FC
2559
2560=item *
2561
2562On compilers that support it, C<-Wwrite-strings> is now added to cflags by
2563default.
2564
2565=item *
2566
2567The C<Encode> module can now (once again) be included in a static Perl
2568build. The special-case handling for this situation got broken in Perl
25695.11.0, and has now been repaired.
2570
1e463951
FC
2571=item *
2572
2573The previous default size of a PerlIO buffer (4096 bytes) has been increased
2574to the larger of 8192 bytes and your local BUFSIZ. Benchmarks show that doubling
2575this decade-old default increases read and write performance in the neighborhood
2576of 25% to 50% when using the default layers of perlio on top of unix. To choose
2577a non-default size, such as to get back the old value or to obtain an even
2578larger value, configure with:
2579
2580 ./Configure -Accflags=-DPERLIOBUF_DEFAULT_BUFSIZ=N
2581
2582where N is the desired size in bytes; it should probably be a multiple of
2583your page size.
2584
d430b8e7
FC
2585=item *
2586
2587An "incompatible operand types" error in ternary expressions when building
2588with C<clang> has been fixed (5.12.2).
2589
2590=item *
2591
2592Perl now skips setuid C<File::Copy> tests on partitions it detects to be mounted
2593as C<nosuid> (5.12.2).
2594
5076a392
FC
2595=back
2596
5076a392
FC
2597=head1 Platform Support
2598
5076a392
FC
2599=head2 New Platforms
2600
5076a392
FC
2601=over 4
2602
2603=item AIX
2604
cdc10f43 2605Perl now builds on AIX 4.2 (5.12.1).
5076a392
FC
2606
2607=back
2608
2609=head2 Discontinued Platforms
2610
2611=over 4
2612
5076a392
FC
2613=item Apollo DomainOS
2614
2615The last vestiges of support for this platform have been excised from the
a60ea503
FC
2616Perl distribution. It was officially discontinued
2617in version 5.12.0. It had
5076a392
FC
2618not worked for years before that.
2619
2620=item MacOS Classic
2621
2622The last vestiges of support for this platform have been excised from the
a60ea503 2623Perl distribution. It was officially discontinued in an earlier version.
5076a392
FC
2624
2625=back
2626
2627=head2 Platform-Specific Notes
2628
d430b8e7
FC
2629=head3 AIX
2630
2631=over
2632
2633=item *
2634
2635F<README.aix> has been updated with information about the XL C/C++ V11 compiler
2636suite (5.12.2).
2637
2638=back
2639
2640=head3 ARM
2641
2642=over
2643
2644=item *
2645
2646The C<d_u32align> configuration probe on ARM has been fixed (5.12.2).
2647
2648=back
2649
554003a2 2650=head3 Cygwin
5076a392
FC
2651
2652=over 4
2653
2654=item *
2655
554003a2 2656MakeMaker has been updated to build man pages on cygwin.
5076a392
FC
2657
2658=item *
2659
554003a2
FC
2660Improved rebase behaviour
2661
2662If a dll is updated on cygwin the old imagebase address is reused.
2663This solves most rebase errors, especially when updating on core dll's.
2664See L<http://www.tishler.net/jason/software/rebase/rebase-2.4.2.README> for more information.
5076a392
FC
2665
2666=item *
2667
554003a2 2668Support for the standard cygwin dll prefix, which is e.g. needed for FFI's
5076a392
FC
2669
2670=item *
2671
554003a2 2672Updated build hints file
5076a392
FC
2673
2674=back
2675
cdc10f43
FC
2676=head3 FreeBSD 7
2677
2678=over
2679
2680=item *
2681
2682FreeBSD 7 no longer contains F</usr/bin/objformat>. At build time,
2683Perl now skips the F<objformat> check for versions 7 and higher and
2684assumes ELF (5.12.1).
2685
2686=back
2687
2688=head3 HP-UX
2689
2690=over
2691
2692=item *
2693
2694Perl now allows -Duse64bitint without promoting to use64bitall on HP-UX
2695(5.12.1).
2696
2697=back
2698
554003a2 2699=head3 IRIX
5076a392 2700
a60ea503
FC
2701=over
2702
2703=item *
2704
5076a392
FC
2705Conversion of strings to floating-point numbers is now more accurate on
2706IRIX systems [perl #32380].
2707
a60ea503
FC
2708=back
2709
554003a2 2710=head3 Mac OS X
5076a392 2711
a60ea503
FC
2712=over
2713
2714=item *
2715
5076a392
FC
2716Early versions of Mac OS X (Darwin) had buggy implementations of the
2717C<setregid>, C<setreuid>, C<setrgid> and C<setruid> functions, so perl
2718would pretend they did not exist.
2719
2720These functions are now recognised on Mac OS 10.5 (Leopard; Darwin 9) and
2721higher, as they have been fixed [perl #72990].
2722
a60ea503
FC
2723=back
2724
554003a2 2725=head3 MirBSD
5076a392 2726
a60ea503
FC
2727=over
2728
2729=item *
2730
554003a2
FC
2731Previously if you built perl with a shared libperl.so on MirBSD (the
2732default config), it would work up to the installation; however, once
2733installed, it would be unable to find libperl. So path handling is now
2734treated as in the other BSD dialects.
5076a392 2735
a60ea503
FC
2736=back
2737
554003a2 2738=head3 NetBSD
5076a392 2739
a60ea503
FC
2740=over
2741
2742=item *
2743
554003a2
FC
2744The NetBSD hints file has been changed to make the system's malloc the
2745default.
5076a392 2746
a60ea503
FC
2747=back
2748
554003a2 2749=head3 Recent OpenBSDs now use perl's malloc
5076a392 2750
a60ea503
FC
2751=over
2752
2753=item *
2754
554003a2
FC
2755OpenBSD E<gt> 3.7 has a new malloc implementation which is mmap-based
2756and as such can release memory back to the OS; however, perl's use of
2757this malloc causes a substantial slowdown so we now default to using
2758perl's malloc instead [perl #75742].
5076a392 2759
a60ea503
FC
2760=back
2761
554003a2 2762=head3 OpenVOS
5076a392 2763
a60ea503
FC
2764=over
2765
2766=item *
2767
554003a2 2768perl now builds again with OpenVOS (formerly known as Stratus VOS)
5a553547 2769[perl #78132] (5.12.3).
5076a392 2770
a60ea503
FC
2771=back
2772
554003a2 2773=head3 Solaris
5076a392 2774
a60ea503
FC
2775=over
2776
2777=item *
2778
2779DTrace is now supported on Solaris. There used to be build failures, but
5a553547 2780these have been fixed [perl #73630] (5.12.3).
5076a392 2781
a60ea503
FC
2782=back
2783
554003a2 2784=head3 VMS
5076a392
FC
2785
2786=over
2787
2788=item *
2789
cdc10f43
FC
2790It's now possible to build extensions on older (pre 7.3-2) VMS systems.
2791
2792DCL symbol length was limited to 1K up until about seven years or
2793so ago, but there was no particularly deep reason to prevent those
2794older systems from configuring and building Perl (5.12.1).
2795
2796=item *
2797
2798We fixed the previously-broken C<-Uuseperlio> build on VMS.
2799
2800We were checking a variable that doesn't exist in the non-default
2801case of disabling perlio. Now we only look at it when it exists (5.12.1).
2802
2803=item *
2804
2805We fixed the -Uuseperlio command-line option in configure.com.
2806
2807Formerly it only worked if you went through all the questions
2808interactively and explicitly answered no (5.12.1).
2809
2810=item *
2811
554003a2 2812C<PerlIOUnix_open> now honours the default permissions on VMS.
5076a392 2813
554003a2
FC
2814When C<perlio> became the default and C<unixio> became the default bottom layer,
2815the most common path for creating files from Perl became C<PerlIOUnix_open>,
2816which has always explicitly used C<0666> as the permission mask.
5076a392 2817
554003a2
FC
2818To avoid this, C<0777> is now passed as the permissions to C<open()>. In the
2819VMS CRTL, C<0777> has a special meaning over and above intersecting with the
2820current umask; specifically, it allows Unix syscalls to preserve native default
5a553547
FC
2821permissions (5.12.3).
2822
2823=item *
2824
2825Spurious record boundaries are no longer
2826introduced by the PerlIO layer during output (5.12.3).
5076a392
FC
2827
2828=item *
2829
554003a2
FC
2830The shortening of symbols longer than 31 characters in the C sources is
2831now done by the compiler rather than by xsubpp (which could only do so
2832for generated symbols in XS code).
5076a392
FC
2833
2834=item *
2835
554003a2
FC
2836Record-oriented files (record format variable or variable with fixed control)
2837opened for write by the perlio layer will now be line-buffered to prevent the
2838introduction of spurious line breaks whenever the perlio buffer fills up.
5076a392 2839
d430b8e7
FC
2840=item *
2841
a60ea503
FC
2842F<git_version.h> is now installed on VMS. This
2843was an oversight in v5.12.0 which
d430b8e7
FC
2844caused some extensions to fail to build (5.12.2).
2845
2846=item *
2847
2848Several memory leaks in L<stat()|perlfunc/"stat FILEHANDLE"> have been fixed (5.12.2).
2849
2850=item *
2851
2852A memory leak in C<Perl_rename()> due to a double allocation has been
2853fixed (5.12.2).
2854
2855=item *
2856
2857A memory leak in C<vms_fid_to_name()> (used by C<realpath()> and
2858C<realname()>) has been fixed (5.12.2).
2859
5076a392
FC
2860=back
2861
554003a2 2862=head3 Windows
5076a392 2863
5a1f7719
FC
2864See also L</"fork() emulation will not wait for signalled children"> and
2865L</"Perl source code is read in text mode on Windows">, above.
2866
5076a392
FC
2867=over 4
2868
2869=item *
2870
554003a2 2871Fixed build process for SDK2003SP1 compilers.
5076a392 2872
554003a2 2873=item *
5076a392 2874
01b1a9e4
FC
2875Compilation with Visual Studio 2010 is now supported.
2876
2877=item *
2878
554003a2
FC
2879When using old 32-bit compilers, the define C<_USE_32BIT_TIME_T> will now
2880be set in C<$Config{ccflags}>. This improves portability when compiling
2881XS extensions using new compilers, but for a perl compiled with old 32-bit
2882compilers.
5076a392
FC
2883
2884=item *
2885
554003a2
FC
2886C<$Config{gccversion}> is now set correctly when perl is built using the
2887mingw64 compiler from L<http://mingw64.org> [perl #73754].
5076a392 2888
554003a2
FC
2889=item *
2890
d430b8e7
FC
2891When building Perl with the mingw64 x64 cross-compiler C<incpath>,
2892C<libpth>, C<ldflags>, C<lddlflags> and C<ldflags_nolargefiles> values
2893in F<Config.pm> and F<Config_heavy.pl> were not previously being set
2894correctly because, with that compiler, the include and lib directories
2895are not immediately below C<$(CCHOME)> (5.12.2).
2896
2897=item *
2898
554003a2
FC
2899The build process proceeds more smoothly with mingw and dmake when
2900F<C:\MSYS\bin> is in the PATH, due to a C<Cwd> fix.
5076a392
FC
2901
2902=item *
2903
554003a2
FC
2904Support for building with Visual C++ 2010 is now underway, but is not yet
2905complete. See F<README.win32> or L<perlwin32> for more details.
5076a392 2906
554003a2
FC
2907=item *
2908
2909The option to use an externally-supplied C<crypt()>, or to build with no
2910C<crypt()> at all, has been removed. Perl supplies its own C<crypt()>
2911implementation for Windows, and the political situation that required
2912this part of the distribution to sometimes be omitted is long gone.
5076a392
FC
2913
2914=back
2915
2916=head1 Internal Changes
2917
1e463951 2918=head2 New APIs
5076a392 2919
1e463951 2920=head3 CLONE_PARAMS structure added to ease correct thread creation
5076a392 2921
1e463951
FC
2922Modules that create threads should now create C<CLONE_PARAMS> structures
2923by calling the new function C<Perl_clone_params_new()>, and free them with
2924C<Perl_clone_params_del()>. This will ensure compatibility with any future
2925changes to the internals of the C<CLONE_PARAMS> structure layout, and that
2926it is correctly allocated and initialised.
5076a392 2927
1e463951 2928=head3 New parsing functions
5076a392 2929
1e463951
FC
2930Several functions have been added for parsing statements or multiple
2931statements:
5076a392 2932
1e463951 2933=over
5076a392
FC
2934
2935=item *
2936
1e463951 2937C<parse_fullstmt> parses a complete Perl statement.
5076a392
FC
2938
2939=item *
2940
1e463951
FC
2941C<parse_stmtseq> parses a sequence of statements, up
2942to closing brace or EOF.
5076a392
FC
2943
2944=item *
2945
1e463951 2946C<parse_block> parses a block [perl #78222].
5076a392
FC
2947
2948=item *
2949
1e463951
FC
2950C<parse_barestmt> parses a statement
2951without a label.
5076a392
FC
2952
2953=item *
2954
1e463951 2955C<parse_label> parses a statement label, separate from statements.
5076a392 2956
1e463951 2957=back
5076a392 2958
1e463951
FC
2959The
2960L<C<parse_fullexpr()>|perlapi/parse_fullexpr>,
2961L<C<parse_listexpr()>|perlapi/parse_listexpr>,
2962L<C<parse_termexpr()>|perlapi/parse_termexpr>, and
2963L<C<parse_arithexpr()>|perlapi/parse_arithexpr>
2964functions have been added to the API. They perform
2965recursive-descent parsing of expressions at various precedence levels.
2966They are expected to be used by syntax plugins.
5076a392 2967
1e463951 2968See L<perlapi> for details.
5076a392 2969
1e463951 2970=head3 Hints hash API
5076a392 2971
1e463951
FC
2972A new C API for introspecting the hinthash C<%^H> at runtime has been
2973added. See C<cop_hints_2hv>, C<cop_hints_fetchpvn>, C<cop_hints_fetchpvs>,
2974C<cop_hints_fetchsv>, and C<hv_copy_hints_hv> in L<perlapi> for details.
5076a392 2975
1e463951
FC
2976A new, experimental API has been added for accessing the internal
2977structure that Perl uses for C<%^H>. See the functions beginning with
2978C<cophh_> in L<perlapi>.
5076a392 2979
1e463951 2980=head3 C interface to C<caller()>
5076a392 2981
1e463951
FC
2982The C<caller_cx> function has been added as an XSUB-writer's equivalent of
2983C<caller()>. See L<perlapi> for details.
5076a392 2984
1e463951 2985=head3 Custom per-subroutine check hooks
5076a392 2986
1e463951
FC
2987XS code in an extension module can now annotate a subroutine (whether
2988implemented in XS or in Perl) so that nominated XS code will be called
2989at compile time (specifically as part of op checking) to change the op
2990tree of that subroutine. The compile-time check function (supplied by
2991the extension module) can implement argument processing that can't be
2992expressed as a prototype, generate customised compile-time warnings,
2993perform constant folding for a pure function, inline a subroutine
2994consisting of sufficiently simple ops, replace the whole call with a
2995custom op, and so on. This was previously all possible by hooking the
2996C<entersub> op checker, but the new mechanism makes it easy to tie the
2997hook to a specific subroutine. See L<perlapi/cv_set_call_checker>.
5076a392 2998
1e463951
FC
2999To help in writing custom check hooks, several subtasks within standard
3000C<entersub> op checking have been separated out and exposed in the API.
5076a392 3001
1e463951 3002=head3 Improved support for custom OPs
5076a392 3003
1e463951
FC
3004Custom ops can now be registered with the new C<custom_op_register> C
3005function and the C<XOP> structure. This will make it easier to add new
3006properties of custom ops in the future. Two new properties have been added
3007already, C<xop_class> and C<xop_peep>.
5076a392 3008
1e463951
FC
3009C<xop_class> is one of the OA_*OP constants, and allows L<B> and other
3010introspection mechanisms to work with custom ops
3011that aren't BASEOPs. C<xop_peep> is a pointer to
3012a function that will be called for ops of this
3013type from C<Perl_rpeep>.
5076a392 3014
1e463951
FC
3015See L<perlguts/Custom Operators> and L<perlapi/Custom Operators> for more
3016detail.
5076a392 3017
1e463951
FC
3018The old C<PL_custom_op_names>/C<PL_custom_op_descs> interface is still
3019supported but discouraged.
5076a392 3020
1e463951 3021=head3 Scope hooks
5076a392 3022
1e463951
FC
3023It is now possible for XS code to hook into Perl's lexical scope
3024mechanism at compile time, using the new C<Perl_blockhook_register>
a60ea503 3025function. See L<perlguts/"Compile-time scope hooks">.
5076a392 3026
1e463951 3027=head3 The recursive part of the peephole optimizer is now hookable
5076a392
FC
3028
3029In addition to C<PL_peepp>, for hooking into the toplevel peephole optimizer, a
3030C<PL_rpeepp> is now available to hook into the optimizer recursing into
3031side-chains of the optree.
3032
1e463951 3033=head3 New non-magical variants of existing functions
5076a392 3034
1e463951
FC
3035The following functions/macros have been added to the API. The C<*_nomg>
3036macros are equivalent to their non-_nomg variants, except that they ignore
3037get-magic. Those ending in C<_flags> allow one to specify whether
3038get-magic is processed.
5076a392 3039
1e463951
FC
3040 sv_2bool_flags
3041 SvTRUE_nomg
3042 sv_2nv_flags
3043 SvNV_nomg
3044 sv_cmp_flags
3045 sv_cmp_locale_flags
3046 sv_eq_flags
3047 sv_collxfrm_flags
5076a392 3048
1e463951 3049In some of these cases, the non-_flags functions have
5076a392
FC
3050been replaced with wrappers around the new functions.
3051
1e463951 3052=head3 pv/pvs/sv versions of existing functions
5076a392 3053
1e463951 3054Many functions ending with pvn now have equivalent pv/pvs/sv versions.
5076a392 3055
1e463951 3056=head3 List op-building functions
5076a392 3057
1e463951
FC
3058List op-building functions have been added to the
3059API. See L<op_append_elem|perlapi/op_append_elem>,
3060L<op_append_list|perlapi/op_append_list>, and
3061L<op_prepend_elem|perlapi/op_prepend_elem> in L<perlapi>.
5076a392 3062
1e463951 3063=head3 C<LINKLIST>
5076a392 3064
1e463951
FC
3065The L<LINKLIST|perlapi/LINKLIST> macro, part of op building that
3066constructs the execution-order op chain, has been added to the API.
5076a392 3067
1e463951 3068=head3 Localisation functions
5076a392 3069
1e463951
FC
3070The C<save_freeop>, C<save_op>, C<save_pushi32ptr> and C<save_pushptrptr>
3071functions have been added to the API.
5076a392 3072
1e463951 3073=head3 Stash names
5076a392 3074
1e463951
FC
3075A stash can now have a list of effective names in addition to its usual
3076name. The first effective name can be accessed via the C<HvENAME> macro,
3077which is now the recommended name to use in MRO linearisations (C<HvNAME>
3078being a fallback if there is no C<HvENAME>).
5076a392 3079
1e463951
FC
3080These names are added and deleted via C<hv_ename_add> and
3081C<hv_ename_delete>. These two functions are I<not> part of the API.
5076a392 3082
1e463951 3083=head3 New functions for finding and removing magic
5076a392 3084
1e463951
FC
3085The L<C<mg_findext()>|perlapi/mg_findext> and
3086L<C<sv_unmagicext()>|perlapi/sv_unmagicext>
3087functions have been added to the API.
3088They allow extension authors to find and remove magic attached to
3089scalars based on both the magic type and the magic virtual table, similar to how
3090C<sv_magicext()> attaches magic of a certain type and with a given virtual table
3091to a scalar. This eliminates the need for extensions to walk the list of
3092C<MAGIC> pointers of an C<SV> to find the magic that belongs to them.
5076a392 3093
1e463951 3094=head3 C<find_rundefsv>
5076a392 3095
1e463951
FC
3096This function returns the SV representing C<$_>, whether it's lexical
3097or dynamic.
5076a392 3098
1e463951 3099=head3 C<Perl_croak_no_modify>
5076a392 3100
1e463951
FC
3101C<Perl_croak_no_modify()> is short-hand for
3102C<Perl_croak("%s", PL_no_modify)>.
5076a392 3103
1e463951 3104=head3 C<PERL_STATIC_INLINE> define
5076a392 3105
1e463951
FC
3106The C<PERL_STATIC_INLINE> define has been added to provide the best-guess
3107incantation to use for static inline functions, if the C compiler supports
3108C99-style static inline. If it doesn't, it'll give a plain C<static>.
5076a392 3109
1e463951
FC
3110C<HAS_STATIC_INLINE> can be used to check if the compiler actually supports
3111inline functions.
5076a392 3112
1e463951 3113=head3 New C<pv_escape> option for hexadecimal escapes
5076a392 3114
1e463951
FC
3115A new option, C<PERL_PV_ESCAPE_NONASCII>, has been added to C<pv_escape> to
3116dump all characters above ASCII in hexadecimal. Before, one could get all
3117characters as hexadecimal or the Latin1 non-ASCII as octal.
5076a392 3118
1e463951 3119=head3 C<lex_start>
5076a392 3120
1e463951 3121C<lex_start> has been added to the API, but is considered experimental.
5076a392 3122
1e463951 3123=head3 C<op_scope()> and C<op_lvalue()>
5076a392 3124
1e463951
FC
3125The C<op_scope()> and C<op_lvalue()> functions have been added to the API,
3126but are considered experimental.
5076a392 3127
1e463951 3128=head2 C API Changes
5076a392 3129
1e463951 3130=head3 C<PERL_POLLUTE> has been removed
5076a392 3131
1e463951
FC
3132The option to define C<PERL_POLLUTE> to expose older 5.005 symbols for
3133backwards compatibility has been removed. It's use was always discouraged,
3134and MakeMaker contains a more specific escape hatch:
5076a392 3135
1e463951 3136 perl Makefile.PL POLLUTE=1
5076a392 3137
1e463951
FC
3138This can be used for modules that have not been upgraded to 5.6 naming
3139conventions (and really should be completely obsolete by now).
5076a392 3140
1e463951 3141=head3 Check API compatibility when loading XS modules
5076a392 3142
1e463951
FC
3143When perl's API changes in incompatible ways (which usually happens between
3144major releases), XS modules compiled for previous versions of perl will not
3145work anymore. They will need to be recompiled against the new perl.
5076a392 3146
1e463951
FC
3147In order to ensure that modules are recompiled, and to prevent users from
3148accidentally loading modules compiled for old perls into newer ones, the
3149C<XS_APIVERSION_BOOTCHECK> macro has been added. That macro, which is
3150called when loading every newly compiled extension, compares the API
3151version of the running perl with the version a module has been compiled for
3152and raises an exception if they don't match.
5076a392 3153
1e463951 3154=head3 Perl_fetch_cop_label
5076a392 3155
1e463951
FC
3156The first argument of the C API function C<Perl_fetch_cop_label> has changed
3157from C<struct refcounted he *> to C<COP *>, to insulate the user from
3158implementation details.
5076a392 3159
1e463951
FC
3160This API function was marked as "may change", and likely isn't in use outside
3161the core. (Neither an unpacked CPAN, nor Google's codesearch, finds any other
3162references to it.)
5076a392 3163
1e463951 3164=head3 GvCV() and GvGP() are no longer lvalues
5076a392 3165
1e463951
FC
3166The new GvCV_set() and GvGP_set() macros are now provided to replace
3167assignment to those two macros.
5076a392 3168
1e463951
FC
3169This allows a future commit to eliminate some backref magic between GV
3170and CVs, which will require complete control over assignment to the
3171gp_cv slot.
5076a392 3172
1e463951 3173=head3 CvGV() is no longer an lvalue
5076a392 3174
1e463951
FC
3175Under some circumstances, the C<CvGV()> field of a CV is now
3176reference-counted. To ensure consistent behaviour, direct assignment to
3177it, for example C<CvGV(cv) = gv> is now a compile-time error. A new macro,
3178C<CvGV_set(cv,gv)> has been introduced to perform this operation
3179safely. Note that modification of this field is not part of the public
3180API, regardless of this new macro (and despite its being listed in this section).
5076a392 3181
1e463951 3182=head3 CvSTASH() is no longer an lvalue
5076a392 3183
1e463951
FC
3184The C<CvSTASH()> macro can now only be used as an rvalue. C<CvSTASH_set()>
3185has been added to replace assignment to C<CvSTASH()>. This is to ensure
3186that backreferences are handled properly. These macros are not part of the
3187API.
5076a392 3188
1e463951 3189=head3 Calling conventions for C<newFOROP> and C<newWHILEOP>
5076a392 3190
1e463951
FC
3191The way the parser handles labels has been cleaned up and refactored. As a
3192result, the C<newFOROP()> constructor function no longer takes a parameter
3193stating what label is to go in the state op.
5076a392 3194
1e463951
FC
3195The C<newWHILEOP()> and C<newFOROP()> functions no longer accept a line
3196number as a parameter.
5076a392 3197
1e463951 3198=head3 Flags passed to C<uvuni_to_utf8_flags> and C<utf8n_to_uvuni>
5076a392 3199
1e463951
FC
3200Some of the flags parameters to uvuni_to_utf8_flags() and
3201utf8n_to_uvuni() have changed. This is a result of Perl's now allowing
5076a392
FC
3202internal storage and manipulation of code points that are problematic
3203in some situations. Hence, the default actions for these functions has
3204been complemented to allow these code points. The new flags are
3205documented in L<perlapi>. Code that requires the problematic code
483b16f3 3206points to be rejected needs to change to use the new flags. Some flag
5076a392
FC
3207names are retained for backward source compatibility, though they do
3208nothing, as they are now the default. However the flags
3209C<UNICODE_ALLOW_FDD0>, C<UNICODE_ALLOW_FFFF>, C<UNICODE_ILLEGAL>, and
3210C<UNICODE_IS_ILLEGAL> have been removed, as they stem from a
3211fundamentally broken model of how the Unicode non-character code points
3212should be handled, which is now described in
52d6192b
FC
3213L<perlunicode/Non-character code points>. See also the Unicode section
3214under L</Selected Bug Fixes>.
5076a392 3215
1e463951 3216=head2 Deprecated C APIs
5076a392 3217
1e463951 3218=over
5076a392 3219
1e463951 3220=item C<Perl_ptr_table_clear>
5076a392 3221
1e463951
FC
3222C<Perl_ptr_table_clear> is no longer part of Perl's public API. Calling it
3223now generates a deprecation warning, and it will be removed in a future
3224release.
5076a392 3225
1e463951 3226=item C<sv_compile_2op>
5076a392 3227
1e463951
FC
3228The C<sv_compile_2op()> API function is now deprecated. Searches suggest
3229that nothing on CPAN is using it, so this should have zero impact.
5076a392 3230
1e463951
FC
3231It attempted to provide an API to compile code down to an optree, but failed
3232to bind correctly to lexicals in the enclosing scope. It's not possible to
3233fix this problem within the constraints of its parameters and return value.
5076a392 3234
1e463951 3235=item C<find_rundefsvoffset>
5076a392 3236
1e463951
FC
3237The C<find_rundefsvoffset> function has been deprecated. It appeared that
3238its design was insufficient for reliably getting the lexical C<$_> at
3239run-time.
5076a392 3240
1e463951 3241Use the new C<find_rundefsv> function or the C<UNDERBAR> macro
cbb8c2bc
FC
3242instead. They directly return the right SV
3243representing C<$_>, whether it's
1e463951 3244lexical or dynamic.
5076a392 3245
1e463951 3246=item C<CALL_FPTR> and C<CPERLscope>
5076a392 3247
1e463951
FC
3248Those are left from an old implementation of C<MULTIPLICITY> using C++ objects,
3249which was removed in Perl 5.8. Nowadays these macros do exactly nothing, so
3250they shouldn't be used anymore.
5076a392 3251
1e463951
FC
3252For compatibility, they are still defined for external C<XS> code. Only
3253extensions defining C<PERL_CORE> must be updated now.
5076a392 3254
1e463951 3255=back
5076a392 3256
1e463951 3257=head2 Other Internal Changes
5076a392 3258
1e463951 3259=head3 Stack unwinding
5076a392 3260
1e463951
FC
3261The protocol for unwinding the C stack at the last stage of a C<die>
3262has changed how it identifies the target stack frame. This now uses
3263a separate variable C<PL_restartjmpenv>, where previously it relied on
3264the C<blk_eval.cur_top_env> pointer in the C<eval> context frame that
3265has nominally just been discarded. This change means that code running
3266during various stages of Perl-level unwinding no longer needs to take
3267care to avoid destroying the ghost frame.
5076a392 3268
1e463951 3269=head3 Scope stack entries
5076a392 3270
1e463951
FC
3271The format of entries on the scope stack has been changed, resulting in a
3272reduction of memory usage of about 10%. In particular, the memory used by
3273the scope stack to record each active lexical variable has been halved.
5076a392 3274
1e463951 3275=head3 Memory allocation for pointer tables
5076a392 3276
1e463951
FC
3277Memory allocation for pointer tables has been changed. Previously
3278C<Perl_ptr_table_store> allocated memory from the same arena system as
3279C<SV> bodies and C<HE>s, with freed memory remaining bound to those arenas
3280until interpreter exit. Now it allocates memory from arenas private to the
3281specific pointer table, and that memory is returned to the system when
3282C<Perl_ptr_table_free> is called. Additionally, allocation and release are
3283both less CPU intensive.
5076a392 3284
1e463951 3285=head3 C<UNDERBAR>
5076a392 3286
1e463951
FC
3287The C<UNDERBAR> macro now calls C<find_rundefsv>. C<dUNDERBAR> is now a
3288noop but should still be used to ensure past and future compatibility.
5076a392 3289
1e463951 3290=head3 String comparison routines renamed
5076a392 3291
1e463951
FC
3292The ibcmp_* functions have been renamed and are now called foldEQ,
3293foldEQ_locale and foldEQ_utf8. The old names are still available as
3294macros.
3295
3296=head3 C<chop> and C<chomp> implementations merged
3297
3298The opcode bodies for C<chop> and C<chomp> and for C<schop> and C<schomp>
3299have been merged. The implementation functions C<Perl_do_chop()> and
3300C<Perl_do_chomp()>, never part of the public API, have been merged and
3301moved to a static function in F<pp.c>. This shrinks the perl binary
3302slightly, and should not affect any code outside the core (unless it is
3303relying on the order of side effects when C<chomp> is passed a I<list> of
3304values).
5076a392
FC
3305
3306=head1 Selected Bug Fixes
3307
e8e35311
FC
3308=head2 I/O
3309
5076a392
FC
3310=over 4
3311
3312=item *
3313
e8e35311 3314Perl no longer produces this warning:
a593b319
FC
3315
3316 $ perl -we 'open my $f, ">", \my $x; binmode $f, "scalar"'
3317 Use of uninitialized value in binmode at -e line 1.
3318
3319=item *
3320
e8e35311
FC
3321Opening a glob reference via C<< open $fh, "E<gt>", \*glob >> will no longer
3322cause the glob to be corrupted when the filehandle is printed to. This would
3323cause perl to crash whenever the glob's contents were accessed
3324[perl #77492].
4ed2cea4
FC
3325
3326=item *
3327
e8e35311 3328PerlIO no longer crashes when called recursively, e.g., from a signal
cbb8c2bc 3329handler. Now it just leaks memory [perl #75556].
4ed2cea4
FC
3330
3331=item *
3332
e8e35311 3333Most I/O functions were not warning for unopened handles unless the
cbb8c2bc 3334'closed' and 'unopened' warnings categories were both enabled. Now only
e8e35311 3335C<use warnings 'unopened'> is necessary to trigger these warnings (as was
438c239f 3336always meant to be the case).
4ed2cea4
FC
3337
3338=item *
3339
438c239f 3340There have been several fixes to PerlIO layers:
e8e35311 3341
438c239f
FC
3342When C<binmode FH, ":crlf"> pushes the C<:crlf> layer on top of the stack,
3343it no longer enables crlf layers lower in the stack, to avoid unexpected
3344results [perl #38456].
4ed2cea4 3345
438c239f
FC
3346Opening a file in C<:raw> mode now does what it advertises to do (first
3347open the file, then binmode it), instead of simply leaving off the top
3348layer [perl #80764].
5076a392 3349
438c239f
FC
3350The three layers C<:pop>, C<:utf8> and C<:bytes> didn't allow stacking when
3351opening a file. For example
e8e35311 3352this:
5076a392 3353
e8e35311 3354 open FH, '>:pop:perlio', 'some.file' or die $!;
5076a392 3355
438c239f
FC
3356Would throw an error: "Invalid argument". This has been fixed in this
3357release [perl #82484].
5076a392 3358
e8e35311
FC
3359=back
3360
3361=head2 Regular Expression Bug Fixes
3362
3363=over
5076a392
FC
3364
3365=item *
3366
e8e35311
FC
3367The regular expression engine no longer loops when matching
3368C<"\N{LATIN SMALL LIGATURE FF}" =~ /f+/i> and similar expressions
cdc10f43 3369[perl #72998] (5.12.1).
5076a392
FC
3370
3371=item *
3372
e8e35311
FC
3373The trie runtime code should no longer allocate massive amounts of memory,
3374fixing #74484.
5076a392
FC
3375
3376=item *
3377
438c239f
FC
3378Syntax errors in C<< (?{...}) >> blocks no longer cause panic messages
3379[perl #2353].
5076a392
FC
3380
3381=item *
3382
438c239f
FC
3383A pattern like C<(?:(o){2})?> no longer causes a "panic" error
3384[perl #39233].
5076a392
FC
3385
3386=item *
3387
438c239f 3388A fatal error in regular expressions containing C<(.*?)> when processing
d430b8e7 3389UTF-8 data has been fixed [perl #75680] (5.12.2).
5076a392
FC
3390
3391=item *
3392
e8e35311 3393An erroneous regular expression engine optimisation that caused regex verbs like
438c239f 3394C<*COMMIT> sometimes to be ignored has been removed.
5076a392
FC
3395
3396=item *
3397
e8e35311
FC
3398The regular expression bracketed character class C<[\8\9]> was effectively the
3399same as C<[89\000]>, incorrectly matching a NULL character. It also gave
3400incorrect warnings that the C<8> and C<9> were ignored. Now C<[\8\9]> is the
3401same as C<[89]> and gives legitimate warnings that C<\8> and C<\9> are
3402unrecognized escape sequences, passed-through.
5076a392
FC
3403
3404=item *
3405
e8e35311
FC
3406A regular expression match in the right-hand side of a global substitution
3407(C<s///g>) that is in the same scope will no longer cause match variables
cbb8c2bc 3408to have the wrong values on subsequent iterations. This can happen when an
e8e35311
FC
3409array or hash subscript is interpolated in the right-hand side, as in
3410C<s|(.)|@a{ print($1), /./ }|g> [perl #19078].
5076a392
FC
3411
3412=item *
3413
438c239f
FC
3414Several cases in which characters in the Latin-1 non-ASCII range (0x80 to
34150xFF) used not to match themselves or used to match both a character class
3416and its complement have been fixed. For instance, U+00E2 could match both
3417C<\w> and C<\W> [perl #78464] [perl #18281] [perl #60156].
5076a392
FC
3418
3419=item *
3420
e8e35311
FC
3421Matching a Unicode character against an alternation containing characters
3422that happened to match continuation bytes in the former's UTF8
3423representation (C<qq{\x{30ab}} =~ /\xab|\xa9/>) would cause erroneous
3424warnings [perl #70998].
5076a392
FC
3425
3426=item *
3427
e8e35311
FC
3428The trie optimisation was not taking empty groups into account, preventing
3429'foo' from matching C</\A(?:(?:)foo|bar|zot)\z/> [perl #78356].
5076a392
FC
3430
3431=item *
3432
e8e35311
FC
3433A pattern containing a C<+> inside a lookahead would sometimes cause an
3434incorrect match failure in a global match (e.g., C</(?=(\S+))/g>)
3435[perl #68564].
5076a392
FC
3436
3437=item *
3438
e8e35311
FC
3439A regular expression optimisation would sometimes cause a match with a
3440C<{n,m}> quantifier to fail when it should match [perl #79152].
5076a392
FC
3441
3442=item *
3443
e8e35311 3444Case insensitive matching in regular expressions compiled under C<use
438c239f
FC
3445locale> now works much more sanely when the pattern or
3446target string is encoded internally in
3447UTF8. Previously, under these conditions the localeness
e8e35311
FC
3448was completely lost. Now, code points above 255 are treated as Unicode,
3449but code points between 0 and 255 are treated using the current locale
438c239f
FC
3450rules, regardless of whether the pattern or the string is encoded in UTF8.
3451The few case-insensitive matches that cross the 255/256 boundary are not
e8e35311
FC
3452allowed. For example, 0xFF does not caselessly match the character at
34530x178, LATIN CAPITAL LETTER Y WITH DIAERESIS, because 0xFF may not be
3454LATIN SMALL LETTER Y in the current locale, and Perl has no way of
3455knowing if that character even exists in the locale, much less what code
3456point it is.
5076a392
FC
3457
3458=item *
3459
e8e35311 3460The C<(?|...)> regular expression construct no longer crashes if the final
cbb8c2bc 3461branch has more sets of capturing parentheses than any other branch. This
e8e35311
FC
3462was fixed in Perl 5.10.1 for the case of a single branch, but that fix did
3463not take multiple branches into account [perl #84746].
5076a392
FC
3464
3465=item *
3466
e8e35311
FC
3467A bug has been fixed in the implementation of C<{...}> quantifiers in
3468regular expressions that prevented the code block in
3469C</((\w+)(?{ print $2 })){2}/> from seeing the C<$2> sometimes
3470[perl #84294].
5076a392 3471
e8e35311 3472=back
5076a392 3473
e8e35311
FC
3474=head2 Syntax/Parsing Bugs
3475
3476=over
5076a392
FC
3477
3478=item *
3479
e8e35311 3480C<when(scalar){...}> no longer crashes, but produces a syntax error
cdc10f43 3481[perl #74114] (5.12.1).
5076a392
FC
3482
3483=item *
3484
e8e35311
FC
3485A label right before a string eval (C<foo: eval $string>) no longer causes
3486the label to be associated also with the first statement inside the eval
3487[perl #74290] (5.12.1).
5076a392
FC
3488
3489=item *
3490
b2c076b5 3491The C<no 5.13.2;> form of C<no> no longer tries to turn on features or
d430b8e7 3492pragmata (i.e., strict) [perl #70075] (5.12.2).
5076a392
FC
3493
3494=item *
3495
b2c076b5
FC
3496C<BEGIN {require 5.12.0}> now behaves as documented, rather than behaving
3497identically to C<use 5.12.0;>. Previously, C<require> in a C<BEGIN> block
3498was erroneously executing the C<use feature ':5.12.0'> and
3499C<use strict;> behaviour, which only C<use> was documented to
3500provide [perl #69050].
5076a392
FC
3501
3502=item *
3503
5076a392
FC
3504A regression introduced in Perl 5.12.0, making
3505C<< my $x = 3; $x = length(undef) >> result in C<$x> set to C<3> has been
d430b8e7 3506fixed. C<$x> will now be C<undef> [perl #85508] (5.12.2).
b2c076b5
FC