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perldelta: more consistent formatting of fullstops
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1=encoding utf8
2
3=head1 NAME
4
5076a392 5perldelta - what is new for perl v5.14.0
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7=head1 DESCRIPTION
8
9This document describes differences between the 5.12.0 release and
10the 5.14.0 release.
11
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12If you are upgrading from an earlier release such as 5.10.0, first read
13L<perl5120delta>, which describes differences between 5.10.0 and
145.12.0.
15
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16Some of the bug fixes in this release have been backported to subsequent
17releases of 5.12.x. Those are indicated with the 5.12.x version in
18parentheses.
19
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20=head1 Notice
21
22XXX Any important notices here
23
24=head1 Core Enhancements
25
1f539a1a 26=head2 Unicode
5076a392 27
1f539a1a 28=head3 Unicode Version 6.0 is now supported (mostly)
5076a392 29
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30Perl comes with the Unicode 6.0 data base updated with
31L<Corrigendum #8|http://www.unicode.org/versions/corrigendum8.html>,
32with one exception noted below.
33See L<http://unicode.org/versions/Unicode6.0.0> for details on the new
34release. Perl does not support any Unicode provisional properties,
a3c24add 35including the new ones for this release.
5076a392 36
1f539a1a 37Unicode 6.0 has chosen to use the name C<BELL> for the character at U+1F514,
e1b1739f 38which is a symbol that looks like a bell, and is used in Japanese cell
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39phones. This conflicts with the long-standing Perl usage of having
40C<BELL> mean the ASCII C<BEL> character, U+0007. In Perl 5.14,
41C<\N{BELL}> will continue to mean U+0007, but its use will generate a
42deprecated warning message, unless such warnings are turned off. The
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43new name for U+0007 in Perl is C<ALERT>, which corresponds nicely
44with the existing shorthand sequence for it, C<"\a">. C<\N{BEL}>
45means U+0007, with no warning given. The character at U+1F514 will not
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46have a name in 5.14, but can be referred to by C<\N{U+1F514}>. The plan
47is that in Perl 5.16, C<\N{BELL}> will refer to U+1F514, and so all code
48that uses C<\N{BELL}> should convert by then to using C<\N{ALERT}>,
49C<\N{BEL}>, or C<"\a"> instead.
5076a392 50
1f539a1a 51=head3 Full functionality for C<use feature 'unicode_strings'>
5076a392 52
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53This release provides full functionality for C<use feature
54'unicode_strings'>. Under its scope, all string operations executed and
55regular expressions compiled (even if executed outside its scope) have
56Unicode semantics. See L<feature>.
5076a392 57
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58This feature avoids most forms of the "Unicode Bug" (See
59L<perlunicode/The "Unicode Bug"> for details.) If there is a
60possibility that your code will process Unicode strings, you are
61B<strongly> encouraged to use this subpragma to avoid nasty surprises.
5076a392 62
1f539a1a 63=head3 C<\N{I<name>}> and C<charnames> enhancements
5076a392 64
1f539a1a 65=over
5076a392 66
1f539a1a 67=item *
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68
69C<\N{}> and C<charnames::vianame> now know about the abbreviated
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70character names listed by Unicode, such as NBSP, SHY, LRO, ZWJ, etc., all
71the customary abbreviations for the C0 and C1 control characters (such as
72ACK, BEL, CAN, etc.), and a few new variants of some C1 full names that
73are in common usage.
5076a392 74
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75=item *
76
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77Unicode has a number of named character sequences, in which particular sequences
78of code points are given names. C<\N{...}> now recognizes these.
79
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80=item *
81
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82C<\N{}>, C<charnames::vianame>, C<charnames::viacode> now know about every
83character in Unicode. Previously, they didn't know about the Hangul syllables
84nor a number of CJK (Chinese/Japanese/Korean) characters.
85
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86=item *
87
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88In the past, it was ineffective to override one of Perl's abbreviations
89with your own custom alias. Now it works.
90
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91=item *
92
e1b1739f 93You can also create a custom alias of the ordinal of a
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94character, known by C<\N{...}>, C<charnames::vianame()>, and
95C<charnames::viacode()>. Previously, an alias had to be to an official
96Unicode character name. This made it impossible to create an alias for
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97a code point that had no name, such as those reserved for private
98use.
5076a392 99
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100=item *
101
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102A new function, C<charnames::string_vianame()>, has been added.
103This function is a run-time version of C<\N{...}>, returning the string
104of characters whose Unicode name is its parameter. It can handle
105Unicode named character sequences, whereas the pre-existing
106C<charnames::vianame()> cannot, as the latter returns a single code
107point.
108
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109=back
110
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111See L<charnames> for details on all these changes.
112
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113=head3 New warnings categories for problematic (non-)Unicode code points.
114
115Three new warnings subcategories of "utf8" have been added. These
116allow you to turn off some "utf8" warnings, while allowing
117others warnings to remain on. The three categories are:
118C<surrogate> when UTF-16 surrogates are encountered;
119C<nonchar> when Unicode non-character code points are encountered;
120and C<non_unicode> when code points that are above the legal Unicode
121maximum of 0x10FFFF are encountered.
122
1f539a1a 123=head3 Any unsigned value can be encoded as a character
5076a392 124
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125With this release, Perl is adopting a model that any unsigned value can
126be treated as a code point and encoded internally (as utf8) without
54c7bb16 127warnings - not just the code points that are legal in Unicode.
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128However, unless utf8 or the corresponding sub-category (see previous
129item) warnings have been
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130explicitly lexically turned off, outputting or performing a
131Unicode-defined operation (such as upper-casing) on such a code point
132will generate a warning. Attempting to input these using strict rules
133(such as with the C<:encoding('UTF-8')> layer) will continue to fail.
134Prior to this release the handling was very inconsistent, and incorrect
135in places. Also, the Unicode non-characters, some of which previously were
136erroneously considered illegal in places by Perl, contrary to the Unicode
137standard, are now always legal internally. But inputting or outputting
138them will work the same as for the non-legal Unicode code points, as the
139Unicode standard says they are illegal for "open interchange".
5076a392 140
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141=head3 Unicode database files not installed
142
143The Unicode database files are no longer installed with Perl. This
144doesn't affect any functionality in Perl and saves significant disk
145space. If you previously were explicitly opening and reading those
146files, you can download them from
147L<http://www.unicode.org/Public/zipped/6.0.0/>.
148
1f539a1a 149=head2 Regular Expressions
5076a392 150
1f539a1a 151=head3 C<(?^...)> construct to signify default modifiers
5076a392 152
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153An ASCII caret (also called a "circumflex accent") C<"^">
154immediately following a C<"(?"> in a regular expression
155now means that the subexpression does not inherit the
156surrounding modifiers such as C</i>, but reverts to the
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157Perl defaults. Any modifiers following the caret override the defaults.
158
159The stringification of regular expressions now uses this
160notation. E.g., before, C<qr/hlagh/i> would be stringified as
161C<(?i-xsm:hlagh)>, but now it's stringified as C<(?^i:hlagh)>.
162
163The main purpose of this is to allow tests that rely on the
e1b1739f 164stringification not to have to change when new modifiers are added.
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165See L<perlre/Extended Patterns>.
166
1f539a1a 167=head3 C</d>, C</l>, C</u>, C</a>, and C</aa> modifiers
5076a392 168
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169Four new regular expression modifiers have been added. These are mutually
170exclusive; one only can be turned on at a time.
5076a392 171
959ad7d5 172The C</l> modifier says to compile the regular expression as if it were
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173in the scope of C<use locale>, even if it is not.
174
959ad7d5 175The C</u> modifier says to compile the regular expression as if it were
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176in the scope of a C<use feature "unicode_strings"> pragma.
177
e1b1739f 178The C</d> (default) modifier is used to override any C<use locale> and
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179C<use feature "unicode_strings"> pragmas that are in effect at the time
180of compiling the regular expression.
181
959ad7d5 182The C</a> regular expression modifier restricts C<\s>, C<\d> and C<\w> and
7baaf023 183the Posix (C<[[:posix:]]>) character classes to the ASCII range. Their
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184complements and C<\b> and C<\B> are correspondingly
185affected. Otherwise, C</a> behaves like the C</u> modifier, in that
e1b1739f 186case-insensitive matching uses Unicode semantics.
5076a392 187
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188The C</aa> modifier is like C</a>, except that, in case-insensitive matching, no ASCII character will match a
189non-ASCII character. For example,
5076a392 190
959ad7d5 191 'k' =~ /\N{KELVIN SIGN}/ai
5076a392 192
959ad7d5 193will match; it won't under C</aa>.
5076a392 194
959ad7d5 195See L<perlre/Modifiers> for more detail.
5076a392 196
1f539a1a 197=head3 Non-destructive substitution
5076a392 198
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199The substitution (C<s///>) and transliteration
200(C<y///>) operators now support an C</r> option that
201copies the input variable, carries out the substitution on
202the copy and returns the result. The original remains unmodified.
5076a392 203
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204 my $old = 'cat';
205 my $new = $old =~ s/cat/dog/r;
206 # $old is 'cat' and $new is 'dog'
5076a392 207
1f539a1a 208This is particularly useful with C<map>. See L<perlop> for more examples.
5076a392 209
1f539a1a 210=head3 Reentrant regular expression engine
5076a392 211
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212It is now safe to use regular expressions within C<(?{...})> and
213C<(??{...})> code blocks inside regular expressions.
5076a392 214
1f539a1a 215These block are still experimental, however, and still have problems with
e1b1739f 216lexical (C<my>) variables and abnormal exiting.
5076a392 217
1f539a1a 218=head3 C<use re '/flags';>
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219
220The C<re> pragma now has the ability to turn on regular expression flags
221till the end of the lexical scope:
222
223 use re '/x';
224 "foo" =~ / (.+) /; # /x implied
225
226See L<re/"'/flags' mode"> for details.
227
1f539a1a 228=head3 \o{...} for octals
5076a392 229
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230There is a new octal escape sequence, C<"\o">, in double-quote-like
231contexts. This construct allows large octal ordinals beyond the
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232current max of 0777 to be represented. It also allows you to specify a
233character in octal which can safely be concatenated with other regex
234snippets and which won't be confused with being a backreference to
235a regex capture group. See L<perlre/Capture groups>.
236
237=head3 Add C<\p{Titlecase}> as a synonym for C<\p{Title}>
238
239This synonym is added for symmetry with the Unicode property names
240C<\p{Uppercase}> and C<\p{Lowercase}>.
5076a392 241
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242=head3 Regular expression debugging output improvement
243
244Regular expression debugging output (turned on by C<use re 'debug';>) now
245uses hexadecimal when escaping non-ASCII characters, instead of octal.
246
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247=head3 Return value of C<delete $+{...}>
248
249Custom regular expression engines can now determine the return value of
250C<delete> on an entry of C<%+> or C<%->.
251
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252=head2 Syntactical Enhancements
253
254=head3 Array and hash container functions accept references
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255
256All built-in functions that operate directly on array or hash
257containers now also accept hard references to arrays or hashes:
258
259 |----------------------------+---------------------------|
260 | Traditional syntax | Terse syntax |
261 |----------------------------+---------------------------|
262 | push @$arrayref, @stuff | push $arrayref, @stuff |
263 | unshift @$arrayref, @stuff | unshift $arrayref, @stuff |
264 | pop @$arrayref | pop $arrayref |
265 | shift @$arrayref | shift $arrayref |
266 | splice @$arrayref, 0, 2 | splice $arrayref, 0, 2 |
267 | keys %$hashref | keys $hashref |
268 | keys @$arrayref | keys $arrayref |
269 | values %$hashref | values $hashref |
270 | values @$arrayref | values $arrayref |
271 | ($k,$v) = each %$hashref | ($k,$v) = each $hashref |
272 | ($k,$v) = each @$arrayref | ($k,$v) = each $arrayref |
273 |----------------------------+---------------------------|
274
275This allows these built-in functions to act on long dereferencing chains
276or on the return value of subroutines without needing to wrap them in
277C<@{}> or C<%{}>:
278
279 push @{$obj->tags}, $new_tag; # old way
280 push $obj->tags, $new_tag; # new way
281
282 for ( keys %{$hoh->{genres}{artists}} ) {...} # old way
283 for ( keys $hoh->{genres}{artists} ) {...} # new way
284
285For C<push>, C<unshift> and C<splice>, the reference will auto-vivify
286if it is not defined, just as if it were wrapped with C<@{}>.
287
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288For C<keys>, C<values>, C<each>, when overloaded dereferencing is
289present, the overloaded dereference is used instead of dereferencing the
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290underlying reftype. Warnings are issued about assumptions made in
291ambiguous cases.
5076a392 292
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293=head3 Single term prototype
294
295The C<+> prototype is a special alternative to C<$> that will act like
296C<\[@%]> when given a literal array or hash variable, but will otherwise
e1b1739f 297force scalar context on the argument. See L<perlsub/Prototypes>.
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298
299=head3 C<package> block syntax
300
301A package declaration can now contain a code block, in which case the
302declaration is in scope only inside that block. So C<package Foo { ... }>
303is precisely equivalent to C<{ package Foo; ... }>. It also works with
304a version number in the declaration, as in C<package Foo 1.2 { ... }>.
e1b1739f 305See L<perlfunc>.
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306
307=head3 Statement labels can appear in more places
308
309Statement labels can now occur before any type of statement or declaration,
310such as C<package>.
311
312=head3 Stacked labels
313
314Multiple statement labels can now appear before a single statement.
315
316=head3 Uppercase X/B allowed in hexadecimal/binary literals
317
318Literals may now use either upper case C<0X...> or C<0B...> prefixes,
319in addition to the already supported C<0x...> and C<0b...>
e1b1739f 320syntax [perl #76296].
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321
322C, Ruby, Python and PHP already supported this syntax, and it makes
323Perl more internally consistent. A round-trip with C<eval sprintf
e1b1739f 324"%#X", 0x10> now returns C<16>, the way C<eval sprintf "%#x", 0x10> does.
1f539a1a 325
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326=head3 Overridable tie functions
327
328C<tie>, C<tied> and C<untie> can now be overridden [perl #75902].
329
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330=head2 Exception Handling
331
332Several changes have been made to the way C<die>, C<warn>, and C<$@>
333behave, in order to make them more reliable and consistent.
334
335When an exception is thrown inside an C<eval>, the exception is no
336longer at risk of being clobbered by code running during unwinding
337(e.g., destructors). Previously, the exception was written into C<$@>
338early in the throwing process, and would be overwritten if C<eval> was
339used internally in the destructor for an object that had to be freed
340while exiting from the outer C<eval>. Now the exception is written
341into C<$@> last thing before exiting the outer C<eval>, so the code
342running immediately thereafter can rely on the value in C<$@> correctly
343corresponding to that C<eval>. (C<$@> is still also set before exiting the
344C<eval>, for the sake of destructors that rely on this.)
345
346Likewise, a C<local $@> inside an C<eval> will no longer clobber any
347exception thrown in its scope. Previously, the restoration of C<$@> upon
348unwinding would overwrite any exception being thrown. Now the exception
349gets to the C<eval> anyway. So C<local $@> is safe before a C<die>.
350
351Exceptions thrown from object destructors no longer modify the C<$@>
352of the surrounding context. (If the surrounding context was exception
353unwinding, this used to be another way to clobber the exception being
354thrown.) Previously such an exception was
355sometimes emitted as a warning, and then either was
356string-appended to the surrounding C<$@> or completely replaced the
357surrounding C<$@>, depending on whether that exception and the surrounding
358C<$@> were strings or objects. Now, an exception in this situation is
359always emitted as a warning, leaving the surrounding C<$@> untouched.
360In addition to object destructors, this also affects any function call
361performed by XS code using the C<G_KEEPERR> flag.
362
363Warnings for C<warn> can now be objects, in the same way as exceptions
364for C<die>. If an object-based warning gets the default handling,
365of writing to standard error, it is stringified as
366before, with the file and line number appended. But
367a C<$SIG{__WARN__}> handler will now receive an
368object-based warning as an object, where previously it was passed the
369result of stringifying the object.
370
371=head2 Other Enhancements
372
373=head3 Assignment to C<$0> sets the legacy process name with C<prctl()> on Linux
374
12f3ad4e 375On Linux the legacy process name is now set with L<prctl(2)>, in
1f539a1a 376addition to altering the POSIX name via C<argv[0]> as perl has done
12f3ad4e 377since version 4.000. Now system utilities that read the legacy process
1f539a1a 378name such as ps, top and killall will recognize the name you set when
12f3ad4e 379assigning to C<$0>. The string you supply will be cut off at 16 bytes;
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380this is a limitation imposed by Linux.
381
382=head3 C<srand()> now returns the seed
383
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384This allows programs that need to have repeatable results not to have to come
385up with their own seed-generating mechanism. Instead, they can use C<srand()>
386and stash the return value for future use. Typical is a test program which
1f539a1a 387has too many combinations to test comprehensively in the time available to it
e1b1739f 388each run. It can test a random subset each time and, should there be a failure,
1f539a1a 389log the seed used for that run so that it can later be used to reproduce the
e1b1739f 390same results.
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391
392=head3 printf-like functions understand post-1980 size modifiers
393
394Perl's printf and sprintf operators, and Perl's internal printf replacement
395function, now understand the C90 size modifiers "hh" (C<char>), "z"
396(C<size_t>), and "t" (C<ptrdiff_t>). Also, when compiled with a C99
397compiler, Perl now understands the size modifier "j" (C<intmax_t>).
398
399So, for example, on any modern machine, C<sprintf('%hhd', 257)> returns '1'.
400
401=head3 New global variable C<${^GLOBAL_PHASE}>
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402
403A new global variable, C<${^GLOBAL_PHASE}>, has been added to allow
404introspection of the current phase of the perl interpreter. It's explained in
405detail in L<perlvar/"${^GLOBAL_PHASE}"> and
406L<perlmod/"BEGIN, UNITCHECK, CHECK, INIT and END">.
407
1f539a1a 408=head3 C<-d:-foo> calls C<Devel::foo::unimport>
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409
410The syntax C<-dI<B<:>foo>> was extended in 5.6.1 to make C<-dI<:fooB<=bar>>>
411equivalent to C<-MDevel::foo=bar>, which expands
412internally to C<use Devel::foo 'bar';>.
413F<perl> now allows prefixing the module name with C<->, with the same
414semantics as C<-M>, I<i.e.>
415
416=over 4
417
418=item C<-d:-foo>
419
420Equivalent to C<-M-Devel::foo>, expands to
421C<no Devel::foo;>, calls C<< Devel::foo->unimport() >>
422if the method exists.
423
424=item C<-d:-foo=bar>
425
426Equivalent to C<-M-Devel::foo=bar>, expands to C<no Devel::foo 'bar';>,
427calls C<< Devel::foo->unimport('bar') >> if the method exists.
428
429=back
430
e1b1739f 431This is particularly useful for suppressing the default actions of a
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432C<Devel::*> module's C<import> method whilst still loading it for debugging.
433
1f539a1a 434=head3 Filehandle method calls load L<IO::File> on demand
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435
436When a method call on a filehandle would die because the method cannot
437be resolved, and L<IO::File> has not been loaded, Perl now loads L<IO::File>
438via C<require> and attempts method resolution again:
439
440 open my $fh, ">", $file;
441 $fh->binmode(":raw"); # loads IO::File and succeeds
442
443This also works for globs like STDOUT, STDERR and STDIN:
444
445 STDOUT->autoflush(1);
446
447Because this on-demand load only happens if method resolution fails, the
448legacy approach of manually loading an L<IO::File> parent class for partial
449method support still works as expected:
450
451 use IO::Handle;
452 open my $fh, ">", $file;
453 $fh->autoflush(1); # IO::File not loaded
454
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455=head3 IPv6 support
456
457The C<Socket> module provides new affordances for IPv6,
458including implementations of the C<Socket::getaddrinfo()> and
459C<Socket::getnameinfo()> functions, along with related constants, and a
460handful of new functions. See L<Socket>.
461
1f539a1a 462=head3 DTrace probes now include package name
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463
464The DTrace probes now include an additional argument (C<arg3>) which contains
465the package the subroutine being entered or left was compiled in.
466
467For example using the following DTrace script:
468
469 perl$target:::sub-entry
470 {
471 printf("%s::%s\n", copyinstr(arg0), copyinstr(arg3));
472 }
473
474and then running:
475
476 perl -e'sub test { }; test'
477
478DTrace will print:
479
480 main::test
481
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482=head2 New C APIs
483
1e463951 484See L</Internal Changes>.
9378886b 485
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486=head1 Security
487
948b8455 488=head2 User-defined regular expression properties
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489
490In L<perlunicode/"User-Defined Character Properties">, it says you can
491create custom properties by defining subroutines whose names begin with
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492"In" or "Is". However, Perl did not actually enforce that naming
493restriction, so \p{foo::bar} could call foo::bar() if it existed. Now this
948b8455 494convention has been enforced.
5076a392 495
948b8455 496Also, Perl no longer allows a tainted regular expression to invoke a
6369b34f 497user-defined property. It simply dies instead [perl #82616].
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498
499=head1 Incompatible Changes
500
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501Perl 5.14.0 is not binary-compatible with any previous stable release.
502
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503In addition to the sections that follow, see L</C API Changes>.
504
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505=head2 Regular Expressions and String Escapes
506
54c7bb16 507=head3 \400-\777
5076a392 508
54c7bb16 509Use of C<\400>-C<\777> in regexes in certain circumstances has given
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510different, anomalous behavior than their use in all other
511double-quote-like contexts. Since 5.10.1, a deprecated warning message
512has been raised when this happens. Now, all double-quote-like contexts
513have the same behavior, namely to be equivalent to C<\x{100}> -
6369b34f 514C<\x{1FF}>, with no deprecation warning. Use of these values in the
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515command line option C<"-0"> retains the current meaning to slurp input
516files whole; previously, this was documented only for C<"-0777">. It is
517recommended, however, because of various ambiguities, to use the new
518C<\o{...}> construct to represent characters in octal.
5076a392 519
61752d82 520=head3 Most C<\p{}> properties are now immune to case-insensitive matching
5076a392 521
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522For most Unicode properties, it doesn't make sense to have them match
523differently under C</i> case-insensitive matching than not. And doing
524so leads to unexpected results and potential security holes. For
525example
5076a392 526
61752d82 527 m/\p{ASCII_Hex_Digit}+/i
5076a392 528
61752d82 529could previously match non-ASCII characters because of the Unicode
4cf6a51f
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530matching rules (although there were a number of bugs with this). Now
531matching under C</i> gives the same results as non-C</i> matching except
532for those few properties where people have come to expect differences,
533namely the ones where casing is an integral part of their meaning, such
534as C<m/\p{Uppercase}/i> and C<m/\p{Lowercase}/i>, both of which match
535the exact same code points, namely those matched by C<m/\p{Cased}/i>.
536Details are in L<perlrecharclass/Unicode Properties>.
5076a392 537
61752d82 538User-defined property handlers that need to match differently under
4cf6a51f 539C</i> must change to read the new boolean parameter passed to them which is
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540non-zero if case-insensitive matching is in effect or 0 otherwise. See
541L<perluniprops/User-Defined Character Properties>.
5076a392 542
61752d82 543=head3 \p{} implies Unicode semantics
5076a392 544
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545Now, a Unicode property match specified in the pattern will indicate
546that the pattern is meant for matching according to Unicode rules, the way
bc15a0a0 547C<\N{}> does.
5076a392 548
61752d82 549=head3 Regular expressions retain their localeness when interpolated
5076a392 550
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551Regular expressions compiled under C<"use locale"> now retain this when
552interpolated into a new regular expression compiled outside a
553C<"use locale">, and vice-versa.
5076a392 554
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555Previously, a regular expression interpolated into another one inherited
556the localeness of the surrounding one, losing whatever state it
557originally had. This is considered a bug fix, but may trip up code that
558has come to rely on the incorrect behavior.
5076a392 559
61752d82 560=head3 Stringification of regexes has changed
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561
562Default regular expression modifiers are now notated by using
563C<(?^...)>. Code relying on the old stringification will fail. The
564purpose of this is so that when new modifiers are added, such code will
565not have to change (after this one time), as the stringification will
566automatically incorporate the new modifiers.
567
568Code that needs to work properly with both old- and new-style regexes
f318e2e6 569can avoid the whole issue by using (for Perls since 5.9.5; see L<re>):
5076a392
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570
571 use re qw(regexp_pattern);
572 my ($pat, $mods) = regexp_pattern($re_ref);
573
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574If the actual stringification is important, or older Perls need to be
575supported, you can use something like the following:
576
577 # Accept both old and new-style stringification
578 my $modifiers = (qr/foobar/ =~ /\Q(?^/) ? '^' : '-xism';
579
580And then use C<$modifiers> instead of C<-xism>.
581
61752d82 582=head3 Run-time code blocks in regular expressions inherit pragmata
5076a392 583
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584Code blocks in regular expressions (C<(?{...})> and C<(??{...})>) used not
585to inherit any pragmata (strict, warnings, etc.) if the regular expression
586was compiled at run time as happens in cases like these two:
5076a392 587
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588 use re 'eval';
589 $foo =~ $bar; # when $bar contains (?{...})
590 $foo =~ /$bar(?{ $finished = 1 })/;
591
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592This was a bug, which has now been fixed. But
593it has the potential to break
61752d82 594any code that was relying on it.
5076a392 595
61752d82 596=head2 Stashes and Package Variables
5076a392 597
61752d82 598=head3 Localised tied hashes and arrays are no longed tied
5076a392 599
61752d82 600In the following:
5076a392 601
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602 tie @a, ...;
603 {
604 local @a;
605 # here, @a is a now a new, untied array
606 }
607 # here, @a refers again to the old, tied array
5076a392 608
61752d82 609The new local array used to be made tied too, which was fairly pointless,
6369b34f 610and has now been fixed. This fix could however potentially cause a change
61752d82 611in behaviour of some code.
5076a392 612
61752d82 613=head3 Stashes are now always defined
5076a392 614
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615C<defined %Foo::> now always returns true, even when no symbols have yet been
616defined in that package.
5076a392 617
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618This is a side effect of removing a special case kludge in the tokeniser,
619added for 5.10.0, to hide side effects of changes to the internal storage of
620hashes that drastically reduce their memory usage overhead.
621
622Calling defined on a stash has been deprecated since 5.6.0, warned on
623lexicals since 5.6.0, and warned for stashes (and other package
6369b34f 624variables) since 5.12.0. C<defined %hash> has always exposed an
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625implementation detail - emptying a hash by deleting all entries from it does
626not make C<defined %hash> false, hence C<defined %hash> is not valid code to
6369b34f 627determine whether an arbitrary hash is empty. Instead, use the behaviour
61752d82
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628that an empty C<%hash> always returns false in a scalar context.
629
630=head3 Dereferencing typeglobs
5076a392
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631
632If you assign a typeglob to a scalar variable:
633
634 $glob = *foo;
635
636the glob that is copied to C<$glob> is marked with a special flag
6369b34f
FC
637indicating that the glob is just a copy. This
638allows subsequent assignments to C<$glob> to
639overwrite the glob. The original glob, however, is
5076a392
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640immutable.
641
642Many Perl operators did not distinguish between these two types of globs.
643This would result in strange behaviour in edge cases: C<untie $scalar>
644would do nothing if the last thing assigned to the scalar was a glob
645(because it treated it as C<untie *$scalar>, which unties a handle).
f318e2e6 646Assignment to a glob slot (e.g., C<*$glob = \@some_array>) would simply
5076a392
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647assign C<\@some_array> to C<$glob>.
648
649To fix this, the C<*{}> operator (including the C<*foo> and C<*$foo> forms)
650has been modified to make a new immutable glob if its operand is a glob
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FC
651copy. This allows operators that make a distinction between globs and
652scalars to be modified to treat only immutable globs as globs. (C<tie>,
653C<tied> and C<untie> have been left as they are for compatibility's sake,
6369b34f 654but will warn. See L</Deprecations>.)
5076a392
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655
656This causes an incompatible change in code that assigns a glob to the
6369b34f 657return value of C<*{}> when that operator was passed a glob copy. Take the
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658following code, for instance:
659
660 $glob = *foo;
661 *$glob = *bar;
662
663The C<*$glob> on the second line returns a new immutable glob. That new
6369b34f 664glob is made an alias to C<*bar>. Then it is discarded. So the second
5076a392
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665assignment has no effect.
666
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667See L<http://rt.perl.org/rt3/Public/Bug/Display.html?id=77810> for even
668more detail.
669
61752d82 670=head3 Clearing stashes
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671
672Stash list assignment C<%foo:: = ()> used to make the stash anonymous
673temporarily while it was being emptied. Consequently, any of its
674subroutines referenced elsewhere would become anonymous (showing up as
675"(unknown)" in C<caller>). Now they retain their package names, such that
676C<caller> will return the original sub name if there is still a reference
677to its typeglob, or "foo::__ANON__" otherwise [perl #79208].
678
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679=head3 Magic variables outside the main package
680
681In previous versions of Perl, magic variables like C<$!>, C<%SIG>, etc. would
682'leak' into other packages. So C<%foo::SIG> could be used to access signals,
683C<${"foo::!"}> (with strict mode off) to access C's C<errno>, etc.
684
685This was a bug, or an 'unintentional' feature, which caused various ill effects,
686such as signal handlers being wiped when modules were loaded, etc.
687
688This has been fixed (or the feature has been removed, depending on how you see
689it).
690
691=head2 Changes to Syntax or to Perl Operators
692
693=head3 C<given> return values
694
695C<given> blocks now return the last evaluated
696expression, or an empty list if the block was exited by C<break>. Thus you
697can now write:
698
699 my $type = do {
700 given ($num) {
701 break when undef;
702 'integer' when /^[+-]?[0-9]+$/;
703 'float' when /^[+-]?[0-9]+(?:\.[0-9]+)?$/;
704 'unknown';
705 }
706 };
707
708See L<perlsyn/Return value> for details.
709
710=head3 Change in the parsing of certain prototypes
711
712Functions declared with the following prototypes now behave correctly as unary
713functions:
714
715 *
716 \$ \% \@ \* \&
717 \[...]
718 ;$ ;*
719 ;\$ ;\% etc.
720 ;\[...]
721
722Due to this bug fix [perl #75904], functions
723using the C<(*)>, C<(;$)> and C<(;*)> prototypes
724are parsed with higher precedence than before. So in the following example:
725
726 sub foo($);
727 foo $a < $b;
728
729the second line is now parsed correctly as C<< foo($a) < $b >>, rather than
730C<< foo($a < $b) >>. This happens when one of these operators is used in
731an unparenthesised argument:
732
733 < > <= >= lt gt le ge
734 == != <=> eq ne cmp ~~
735 &
736 | ^
737 &&
738 || //
739 .. ...
740 ?:
741 = += -= *= etc.
742
743=head3 Smart-matching against array slices
744
745Previously, the following code resulted in a successful match:
746
747 my @a = qw(a y0 z);
748 my @b = qw(a x0 z);
749 @a[0 .. $#b] ~~ @b;
750
751This odd behaviour has now been fixed [perl #77468].
752
753=head3 Negation treats strings differently from before
754
755The unary negation operator C<-> now treats strings that look like numbers
756as numbers [perl #57706].
757
758=head3 Negative zero
759
760Negative zero (-0.0), when converted to a string, now becomes "0" on all
761platforms. It used to become "-0" on some, but "0" on others.
762
763If you still need to determine whether a zero is negative, use
764C<sprintf("%g", $zero) =~ /^-/> or the L<Data::Float> module on CPAN.
765
766=head3 C<:=> is now a syntax error
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767
768Previously C<my $pi := 4;> was exactly equivalent to C<my $pi : = 4;>,
769with the C<:> being treated as the start of an attribute list, ending before
770the C<=>. The use of C<:=> to mean C<: => was deprecated in 5.12.0, and is now
771a syntax error. This will allow the future use of C<:=> as a new token.
772
773We find no Perl 5 code on CPAN using this construction, outside the core's
774tests for it, so we believe that this change will have very little impact on
775real-world codebases.
776
777If it is absolutely necessary to have empty attribute lists (for example,
778because of a code generator) then avoid the error by adding a space before
779the C<=>.
780
61752d82 781=head2 Threads and Processes
5076a392 782
61752d82 783=head3 Directory handles not copied to threads
5076a392 784
61752d82
FC
785On systems other than Windows that do not have
786a C<fchdir> function, newly-created threads no
787longer inherit directory handles from their parent threads. Such programs
788would usually have crashed anyway [perl #75154].
5076a392 789
61752d82 790=head3 C<close> on shared pipes
5076a392 791
61752d82
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792The C<close> function no longer waits for the child process to exit if the
793underlying file descriptor is still in use by another thread, to avoid
794deadlocks. It returns true in such cases.
5076a392 795
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796=head3 fork() emulation will not wait for signalled children
797
798On Windows parent processes would not terminate until all forked
799childred had terminated first. However, C<kill('KILL', ...)> is
800inherently unstable on pseudo-processes, and C<kill('TERM', ...)>
801might not get delivered if the child if blocked in a system call.
802
803To avoid the deadlock and still provide a safe mechanism to terminate
804the hosting process, Perl will now no longer wait for children that
805have been sent a SIGTERM signal. It is up to the parent process to
806waitpid() for these children if child clean-up processing must be
807allowed to finish. However, it is also the responsibility of the
808parent then to avoid the deadlock by making sure the child process
809can't be blocked on I/O either.
810
811See L<perlfork> for more information about the fork() emulation on
812Windows.
813
61752d82 814=head2 Configuration
5076a392 815
61752d82 816=head3 Naming fixes in Policy_sh.SH may invalidate Policy.sh
5076a392 817
61752d82
FC
818Several long-standing typos and naming confusions in Policy_sh.SH have
819been fixed, standardizing on the variable names used in config.sh.
5076a392 820
61752d82
FC
821This will change the behavior of Policy.sh if you happen to have been
822accidentally relying on the Policy.sh incorrect behavior.
f318e2e6 823
5a1f7719
FC
824=head3 Perl source code is read in text mode on Windows
825
826Perl scripts used to be read in binary mode on Windows for the benefit
827of the ByteLoader module (which is no longer part of core Perl). This
828had the side effect of breaking various operations on the DATA filehandle,
829including seek()/tell(), and even simply reading from DATA after file handles
830have been flushed by a call to system(), backticks, fork() etc.
831
832The default build options for Windows have been changed to read Perl source
833code on Windows in text mode now. Hopefully ByteLoader will be updated on
834CPAN to automatically handle this situation [perl #28106].
835
5076a392
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836=head1 Deprecations
837
1e463951
FC
838See also L</Deprecated C APIs>.
839
5076a392
FC
840=head2 Omitting a space between a regular expression and subsequent word
841
18139a1b
FC
842Omitting a space between a regular expression operator or
843its modifiers and the following word is deprecated. For
844example, C<< m/foo/sand $bar >> will still be parsed
845as C<< m/foo/s and $bar >> but will issue a warning.
5076a392 846
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847=head2 C<\cI<X>>
848
849The backslash-c construct was designed as a way of specifying
850non-printable characters, but there were no restrictions (on ASCII
851platforms) on what the character following the C<c> could be. Now,
852a deprecation warning is raised if that character isn't an ASCII character.
853Also, a deprecation warning is raised for C<"\c{"> (which is the same
854as simply saying C<";">).
855
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856=head2 C<"\b{"> and C<"\B{">
857
858In regular expressions, a literal C<"{"> immediately following a C<"\b">
859(not in a bracketed character class) or a C<"\B{"> is now deprecated
860to allow for its future use by Perl itself.
861
5076a392
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862=head2 Deprecation warning added for deprecated-in-core .pl libs
863
864This is a mandatory warning, not obeying -X or lexical warning bits.
865The warning is modelled on that supplied by deprecate.pm for
866deprecated-in-core .pm libraries. It points to the specific CPAN
823d0e46
FC
867distribution that contains the .pl libraries. The CPAN version, of
868course, does not generate the warning.
5076a392
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869
870=head2 List assignment to C<$[>
871
823d0e46
FC
872Assignment to C<$[> was deprecated and started to give warnings in
873Perl version 5.12.0. This version of perl also starts to emit a warning when
874assigning to C<$[> in list context. This fixes an oversight in 5.12.0.
5076a392
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875
876=head2 Use of qw(...) as parentheses
877
878Historically the parser fooled itself into thinking that C<qw(...)> literals
879were always enclosed in parentheses, and as a result you could sometimes omit
880parentheses around them:
881
882 for $x qw(a b c) { ... }
883
884The parser no longer lies to itself in this way. Wrap the list literal in
823d0e46 885parentheses, like this:
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886
887 for $x (qw(a b c)) { ... }
888
889=head2 C<\N{BELL}> is deprecated
890
891This is because Unicode is using that name for a different character.
892See L</Unicode Version 6.0 is now supported (mostly)> for more
893explanation.
894
895=head2 C<?PATTERN?> is deprecated
896
897C<?PATTERN?> (without the initial m) has been deprecated and now produces
898a warning. This is to allow future use of C<?> in new operators.
899The match-once functionality is still available in the form of C<m?PATTERN?>.
900
5076a392
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901=head2 Tie functions on scalars holding typeglobs
902
903Calling a tie function (C<tie>, C<tied>, C<untie>) with a scalar argument
904acts on a file handle if the scalar happens to hold a typeglob.
905
906This is a long-standing bug that will be removed in Perl 5.16, as
907there is currently no way to tie the scalar itself when it holds
908a typeglob, and no way to untie a scalar that has had a typeglob
909assigned to it.
910
823d0e46 911Now there is a deprecation warning whenever a tie
5076a392
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912function is used on a handle without an explicit C<*>.
913
18139a1b 914=head2 User-defined case-mapping
5076a392 915
18139a1b
FC
916This feature is being deprecated due to its many issues, as documented in
917L<perlunicode/User-Defined Case Mappings (for serious hackers only)>.
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918It is planned to remove this feature in Perl 5.16. Instead use the CPAN module
919L<Unicode::Casing>, which provides improved functionality.
823d0e46 920
18139a1b 921=head2 Deprecated modules
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922
923The following modules will be removed from the core distribution in a
924future release, and should be installed from CPAN instead. Distributions
925on CPAN which require these should add them to their prerequisites. The
823d0e46 926core versions of these modules will issue a deprecation warning.
5076a392
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927
928If you ship a packaged version of Perl, either alone or as part of a
929larger system, then you should carefully consider the repercussions of
823d0e46 930core module deprecations. You may want to consider shipping your default
5076a392 931build of Perl with packages for some or all deprecated modules which
823d0e46 932install into C<vendor> or C<site> perl library directories. This will
5076a392
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933inhibit the deprecation warnings.
934
935Alternatively, you may want to consider patching F<lib/deprecate.pm>
936to provide deprecation warnings specific to your packaging system
937or distribution of Perl, consistent with how your packaging system
938or distribution manages a staged transition from a release where the
939installation of a single package provides the given functionality, to
940a later release where the system administrator needs to know to install
941multiple packages to get that same functionality.
942
943You can silence these deprecation warnings by installing the modules
944in question from CPAN. To install the latest version of all of them,
945just install C<Task::Deprecations::5_14>.
946
947=over
948
949=item L<Devel::DProf>
950
951We strongly recommend that you install and used L<Devel::NYTProf> in
952preference, as it offers significantly improved profiling and reporting.
953
954=back
955
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956=head1 Performance Enhancements
957
54c7bb16 958=head2 "Safe signals" optimisation
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959
960Signal dispatch has been moved from the runloop into control ops. This
961should give a few percent speed increase, and eliminates almost all of
962the speed penalty caused by the introduction of "safe signals" in
9635.8.0. Signals should still be dispatched within the same statement as
964they were previously - if this is not the case, or it is possible to
965create uninterruptible loops, this is a bug, and reports are encouraged
966of how to recreate such issues.
967
54c7bb16 968=head2 Optimisation of shift; and pop; calls without arguments
df91d470 969
111b6aa7
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970Two fewer OPs are used for shift and pop calls with no argument (with
971implicit C<@_>). This change makes C<shift;> 5% faster than C<shift @_;>
972on non-threaded perls and 25% faster on threaded.
df91d470 973
fa232254 974=head2 Optimisation of regexp engine string comparison work
df91d470 975
fa232254
FC
976The foldEQ_utf8 API function for case-insensitive comparison of strings (which
977is used heavily by the regexp engine) was substantially refactored and
978optimised - and its documentation much improved as a free bonus gift.
df91d470 979
fa232254 980=head2 Regular expression compilation speed-up
df91d470 981
fa232254
FC
982Compiling regular expressions has been made faster for the case where upgrading
983the regex to utf8 is necessary but that isn't known when the compilation begins.
df91d470 984
fa232254 985=head2 String appending is 100 times faster
df91d470 986
fa232254
FC
987When doing a lot of string appending, perl could end up allocating a lot more
988memory than needed in a very inefficient way, if perl was configured to use the
989system's C<malloc> implementation instead of its own.
990
991C<sv_grow>, which is what's being used to allocate more memory if necessary
992when appending to a string, has now been taught how to round up the memory
993it requests to a certain geometric progression, making it much faster on
994certain platforms and configurations. On Win32, it's now about 100 times
995faster.
996
997=head2 Eliminate C<PL_*> accessor functions under ithreads
998
999When C<MULTIPLICITY> was first developed, and interpreter state moved into
1000an interpreter struct, thread and interpreter local C<PL_*> variables were
1001defined as macros that called accessor functions, returning the address of
1002the value, outside of the perl core. The intent was to allow members
1003within the interpreter struct to change size without breaking binary
1004compatibility, so that bug fixes could be merged to a maintenance branch
1005that necessitated such a size change.
1006
1007However, some non-core code defines C<PERL_CORE>, sometimes intentionally
1008to bypass this mechanism for speed reasons, sometimes for other reasons but
1009with the inadvertent side effect of bypassing this mechanism. As some of
1010this code is widespread in production use, the result is that the core
1011I<can't> change the size of members of the interpreter struct, as it will
1012break such modules compiled against a previous release on that maintenance
1013branch. The upshot is that this mechanism is redundant, and well-behaved
1014code is penalised by it. Hence it can and should be removed (and has
1015been).
1016
1017=head2 Freeing weak references
1018
1019When an object has many weak references to it, freeing that object
1020can under some some circumstances take O(N^2) time to free (where N is the
1021number of references). The number of circumstances has been reduced
1022[perl #75254]
1023
1024=head2 Lexical array and hash assignments
1025
1026An earlier optimisation to speed up C<my @array = ...> and
1027C<my %hash = ...> assignments caused a bug and was disabled in Perl 5.12.0.
1028
1029Now we have found another way to speed up these assignments [perl #82110].
df91d470 1030
111b6aa7 1031=head2 C<@_> uses less memory
df91d470 1032
111b6aa7
FC
1033Previously, C<@_> was allocated for every subroutine at compile time with
1034enough space for four entries. Now this allocation is done on demand when
1035the subroutine is called [perl #72416].
5076a392 1036
5076a392
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1037=head2 Size optimisations to SV and HV structures
1038
1039xhv_fill has been eliminated from struct xpvhv, saving 1 IV per hash and
111b6aa7 1040on some systems will cause struct xpvhv to become cache-aligned. To avoid
5076a392
FC
1041this memory saving causing a slowdown elsewhere, boolean use of HvFILL
1042now calls HvTOTALKEYS instead (which is equivalent) - so while the fill
111b6aa7
FC
1043data when actually required are now calculated on demand, the cases when
1044this needs to be done should be few and far between.
5076a392 1045
111b6aa7
FC
1046The order of structure elements in SV bodies has changed. Effectively,
1047the NV slot has swapped location with STASH and MAGIC. As all access to
1048SV members is via macros, this should be completely transparent. This
5076a392
FC
1049change allows the space saving for PVHVs documented above, and may reduce
1050the memory allocation needed for PVIVs on some architectures.
1051
fa232254
FC
1052C<XPV>, C<XPVIV>, and C<XPVNV> now only allocate the parts of the C<SV> body
1053they actually use, saving some space.
5076a392 1054
fa232254
FC
1055Scalars containing regular expressions now only allocate the part of the C<SV>
1056body they actually use, saving some space.
5076a392
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1057
1058=head2 Memory consumption improvements to Exporter
1059
1060The @EXPORT_FAIL AV is no longer created unless required, hence neither is
111b6aa7
FC
1061the typeglob backing it. This saves about 200 bytes for every package that
1062uses Exporter but doesn't use this functionality.
5076a392 1063
111b6aa7 1064=head2 Memory savings for weak references
5076a392
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1065
1066For weak references, the common case of just a single weak reference per
1067referent has been optimised to reduce the storage required. In this case it
111b6aa7 1068saves the equivalent of one small Perl array per referent.
5076a392 1069
111b6aa7 1070=head2 C<%+> and C<%-> use less memory
5076a392
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1071
1072The bulk of the C<Tie::Hash::NamedCapture> module used to be in the perl
111b6aa7 1073core. It has now been moved to an XS module, to reduce the overhead for
5076a392
FC
1074programs that do not use C<%+> or C<%->.
1075
fa232254 1076=head2 Multiple small improvements to threads
5076a392 1077
fa232254
FC
1078The internal structures of threading now make fewer API calls and fewer
1079allocations, resulting in noticeably smaller object code. Additionally,
1080many thread context checks have been deferred so that they're only done
1081when required (although this is only possible for non-debugging builds).
5076a392 1082
fa232254 1083=head2 Adjacent pairs of nextstate opcodes are now optimized away
5076a392 1084
fa232254 1085Previously, in code such as
5076a392 1086
fa232254 1087 use constant DEBUG => 0;
5076a392 1088
fa232254
FC
1089 sub GAK {
1090 warn if DEBUG;
1091 print "stuff\n";
1092 }
5076a392 1093
fa232254
FC
1094the ops for C<warn if DEBUG;> would be folded to a C<null> op (C<ex-const>), but
1095the C<nextstate> op would remain, resulting in a runtime op dispatch of
1096C<nextstate>, C<nextstate>, ....
5076a392 1097
fa232254
FC
1098The execution of a sequence of C<nextstate> ops is indistinguishable from just
1099the last C<nextstate> op so the peephole optimizer now eliminates the first of
1100a pair of C<nextstate> ops, except where the first carries a label, since labels
1101must not be eliminated by the optimizer and label usage isn't conclusively known
1102at compile time.
5076a392
FC
1103
1104=head1 Modules and Pragmata
1105
1106=head2 New Modules and Pragmata
1107
1108=over 4
1109
1110=item *
1111
1112C<CPAN::Meta::YAML> 0.003 has been added as a dual-life module. It supports a
1113subset of YAML sufficient for reading and writing META.yml and MYMETA.yml files
1114included with CPAN distributions or generated by the module installation
1115toolchain. It should not be used for any other general YAML parsing or
1116generation task.
1117
1118=item *
1119
1120C<CPAN::Meta> version 2.110440 has been added as a dual-life module. It
1121provides a standard library to read, interpret and write CPAN distribution
1122metadata files (e.g. META.json and META.yml) which describes a
1123distribution, its contents, and the requirements for building it and
1124installing it. The latest CPAN distribution metadata specification is
1125included as C<CPAN::Meta::Spec> and notes on changes in the specification
1126over time are given in C<CPAN::Meta::History>.
1127
1128=item *
1129
5a553547 1130C<HTTP::Tiny> 0.011 has been added as a dual-life module. It is a very
5076a392
FC
1131small, simple HTTP/1.1 client designed for simple GET requests and file
1132mirroring. It has has been added to enable CPAN.pm and CPANPLUS to
1133"bootstrap" HTTP access to CPAN using pure Perl without relying on external
1134binaries like F<curl> or F<wget>.
1135
1136=item *
1137
1138C<JSON::PP> 2.27105 has been added as a dual-life module, for the sake of
1139reading F<META.json> files in CPAN distributions.
1140
1141=item *
1142
21ef4e45 1143C<Module::Metadata> 1.000004 has been added as a dual-life module. It gathers
5076a392
FC
1144package and POD information from Perl module files. It is a standalone module
1145based on Module::Build::ModuleInfo for use by other module installation
1146toolchain components. Module::Build::ModuleInfo has been deprecated in
1147favor of this module instead.
1148
1149=item *
1150
1151C<Perl::OSType> 1.002 has been added as a dual-life module. It maps Perl
1152operating system names (e.g. 'dragonfly' or 'MSWin32') to more generic types
1153with standardized names (e.g. "Unix" or "Windows"). It has been refactored
1154out of Module::Build and ExtUtils::CBuilder and consolidates such mappings into
1155a single location for easier maintenance.
1156
1157=item *
1158
1159The following modules were added by the C<Unicode::Collate>
1160upgrade. See below for details.
1161
1162C<Unicode::Collate::CJK::Big5>
1163
1164C<Unicode::Collate::CJK::GB2312>
1165
1166C<Unicode::Collate::CJK::JISX0208>
1167
1168C<Unicode::Collate::CJK::Korean>
1169
1170C<Unicode::Collate::CJK::Pinyin>
1171
1172C<Unicode::Collate::CJK::Stroke>
1173
1174=item *
1175
1176C<Version::Requirements> version 0.101020 has been added as a dual-life
1177module. It provides a standard library to model and manipulates module
1178prerequisites and version constraints as defined in the L<CPAN::Meta::Spec>.
1179
1180=back
1181
a5794e94 1182=head2 Updated Modules and Pragma
5076a392
FC
1183
1184=over 4
1185
1186=item *
1187
81a53be2
FR
1188C<attributes> has been upgraded from version 0.12 to 0.14.
1189
1190=item *
1191
5076a392
FC
1192C<Archive::Extract> has been upgraded from version 0.38 to 0.48.
1193
1194Updates since 0.38 include: a safe print method that guards
1195Archive::Extract from changes to $\; a fix to the tests when run in core
1984204c
FC
1196perl; support for TZ files; a modification for the lzma
1197logic to favour IO::Uncompress::Unlzma; and a fix
1198for an issue with NetBSD-current and its new unzip
5076a392
FC
1199executable.
1200
1201=item *
1202
1203C<Archive::Tar> has been upgraded from version 1.54 to 1.76.
1204
1984204c
FC
1205Important changes since 1.54 include the following:
1206
1207=over
1208
1209=item *
1210
1211Compatibility with busybox implementations of tar
1212
1213=item *
1214
1215A fix so that C<write()> and C<create_archive()>
1216close only handles they opened
1217
1218=item *
1219
1220A bug was fixed regarding the exit code of extract_archive.
5076a392 1221
1984204c
FC
1222=item *
1223
4f978a3b 1224The C<ptar> utility has a new option to allow safe
5076a392
FC
1225creation of tarballs without world-writable files on Windows, allowing those
1226archives to be uploaded to CPAN.
1227
1984204c
FC
1228=item *
1229
1230A new ptargrep utility for using regular expressions against
5076a392
FC
1231the contents of files in a tar archive.
1232
1984204c
FC
1233=item *
1234
1235Pax extended headers are now skipped.
1236
1237=back
5076a392
FC
1238
1239=item *
1240
fcd5df6d
FR
1241C<Attribute::Handlers> has been upgraded from version 0.87 to 0.89.
1242
1243=item *
1244
3f5a47e4
FR
1245C<autodie> has been upgraded from version 2.06_01 to 2.1001.
1246
1247=item *
1248
578e7c9d
FR
1249C<AutoLoader> has been upgraded from version 5.70 to 5.71.
1250
1251=item *
1252
a13baafd 1253C<B> has been upgraded from version 1.23 to 1.29.
5076a392
FC
1254
1255It no longer crashes when taking apart a C<y///> containing characters
1256outside the octet range or compiled in a C<use utf8> scope.
1257
1258The size of the shared object has been reduced by about 40%, with no
1259reduction in functionality.
1260
1261=item *
1262
4a75fbf5 1263C<B::Concise> has been upgraded from version 0.78 to 0.83.
5076a392
FC
1264
1265B::Concise marks rv2sv, rv2av and rv2hv ops with the new OPpDEREF flag
1266as "DREFed".
1267
1268It no longer produces mangled output with the C<-tree> option
1269[perl #80632].
1270
1271=item *
1272
6bb8c1e3
FR
1273C<B::Debug> has been upgraded from version 1.12 to 1.16.
1274
1275=item *
1276
c67a4e29 1277C<B::Deparse> has been upgraded from version 0.96 to 1.03.
5076a392 1278
1984204c 1279The deparsing of a nextstate op has changed when it has both a
5076a392
FC
1280change of package (relative to the previous nextstate), or a change of
1281C<%^H> or other state, and a label. Previously the label was emitted
cdc10f43 1282first, but now the label is emitted last (5.12.1).
5076a392 1283
5a553547
FC
1284The C<no 5.13.2> or similar form is now correctly handled by B::Deparse
1285(5.12.3).
5076a392
FC
1286
1287B::Deparse now properly handles the code that applies a conditional
1288pattern match against implicit C<$_> as it was fixed in [perl #20444].
1289
1984204c
FC
1290Deparsing of C<our> followed by a variable with funny characters
1291(as permitted under the C<utf8> pragma) has also been fixed [perl #33752].
5076a392
FC
1292
1293=item *
1294
d97c5d3b
FR
1295C<B::Lint> has been upgraded from version 1.11_01 to 1.13.
1296
1297=item *
1298
5aef2c44
FR
1299C<base> has been upgraded from version 2.15 to 2.16.
1300
1301=item *
1302
876607aa
FR
1303C<Benchmark> has been upgraded from version 1.11 to 1.12.
1304
1305=item *
1306
e539ae69
FR
1307C<bignum> has been upgraded from version 0.23 to 0.26.
1308
1309=item *
1310
c74c1fa8 1311C<Carp> has been upgraded from version 1.15 to 1.20.
5076a392
FC
1312
1313L<Carp> now detects incomplete L<caller()|perlfunc/"caller EXPR"> overrides and
d430b8e7
FC
1314avoids using bogus C<@DB::args>. To provide backtraces,
1315Carp relies on particular behaviour of the C<caller>
1316built-in. Carp now detects if other code has
5076a392 1317overridden this with an incomplete implementation, and modifies its backtrace
d430b8e7
FC
1318accordingly. Previously incomplete overrides would cause incorrect values
1319in backtraces (best case), or obscure fatal errors (worst case).
5076a392
FC
1320
1321This fixes certain cases of C<Bizarre copy of ARRAY> caused by modules
d430b8e7 1322overriding C<caller()> incorrectly (5.12.2).
5076a392 1323
1984204c 1324It now also avoids using regular expressions that cause perl to
5076a392
FC
1325load its Unicode tables, in order to avoid the 'BEGIN not safe after
1326errors' error that will ensue if there has been a syntax error
1327[perl #82854].
1328
1329=item *
1330
9eb7ad55 1331C<CGI> has been upgraded from version 3.48 to 3.52.
5076a392
FC
1332
1333This provides the following security fixes: the MIME boundary in
1984204c
FC
1334multipart_init is now random and the handling of
1335newlines embedded in header values has been improved.
5076a392
FC
1336
1337=item *
1338
5076a392
FC
1339C<Compress::Raw::Bzip2> has been upgraded from version 2.024 to 2.033.
1340
1984204c 1341It has been updated to use bzip2 1.0.6.
5076a392
FC
1342
1343=item *
1344
51090521
FR
1345C<Compress::Raw::Zlib> has been upgraded from version 2.024 to 2.033.
1346
1347=item *
1348
f75b7efc 1349C<CPAN> has been upgraded from version 1.94_56 to 1.9600.
1984204c
FC
1350
1351Major highlights:
5076a392
FC
1352
1353=over 4
1354
1984204c 1355=item * much less configuration dialog hassle
5076a392 1356
1984204c 1357=item * support for META/MYMETA.json
5076a392 1358
1984204c 1359=item * support for local::lib
5076a392 1360
1984204c 1361=item * support for HTTP::Tiny to reduce the dependency on ftp sites
5076a392 1362
1984204c 1363=item * automatic mirror selection
5076a392 1364
1984204c 1365=item * iron out all known bugs in configure_requires
5076a392 1366
1984204c
FC
1367=item * support for distributions compressed with bzip2
1368
1369=item * allow Foo/Bar.pm on the commandline to mean Foo::Bar
1370
1371=back
5076a392
FC
1372
1373=item *
1374
d430b8e7
FC
1375C<CPANPLUS> has been upgraded from version 0.90 to 0.9103.
1376
1377A change to F<cpanp-run-perl>
1378resolves L<RT #55964|http://rt.cpan.org/Public/Bug/Display.html?id=55964>
1379and L<RT #57106|http://rt.cpan.org/Public/Bug/Display.html?id=57106>, both
1380of which related to failures to install distributions that use
1381C<Module::Install::DSL> (5.12.2).
5076a392 1382
1984204c
FC
1383A dependency on Config was not recognised as a
1384core module dependency. This has been fixed.
5076a392 1385
1984204c 1386CPANPLUS now includes support for META.json and MYMETA.json.
5076a392
FC
1387
1388=item *
1389
4467e8f7
FR
1390C<CPANPLUS::Dist::Build> has been upgraded from version 0.46 to 0.54.
1391
1392=item *
1393
5076a392
FC
1394C<Data::Dumper> has been upgraded from version 2.125 to 2.130_02.
1395
4ed2cea4
FC
1396The indentation used to be off when C<$Data::Dumper::Terse> was set. This
1397has been fixed [perl #73604].
1398
1984204c
FC
1399This upgrade also fixes a crash when using custom sort functions that might
1400cause the stack to change [perl #74170].
5076a392
FC
1401
1402C<Dumpxs> no longer crashes with globs returned by C<*$io_ref>
1403[perl #72332].
1404
1405=item *
1406
549d34f5
FR
1407C<DB_File> has been upgraded from version 1.820 to 1.821.
1408
1409=item *
1410
851dbda2
FR
1411C<DBM_Filter> has been upgraded from version 0.03 to 0.04.
1412
1413=item *
1414
5076a392
FC
1415C<Devel::DProf> has been upgraded from version 20080331.00 to 20110228.00.
1416
1417Merely loading C<Devel::DProf> now no longer triggers profiling to start.
1418C<use Devel::DProf> and C<perl -d:DProf ...> still behave as before and start
1419the profiler.
1420
1421NOTE: C<Devel::DProf> is deprecated and will be removed from a future
1984204c 1422version of Perl. We strongly recommend that you install and use
5076a392
FC
1423L<Devel::NYTProf> instead, as it offers significantly improved
1424profiling and reporting.
1425
1426=item *
1427
868625d2
FR
1428C<Devel::Peek> has been upgraded from version 1.04 to 1.07.
1429
1430=item *
1431
66899ca3
FR
1432C<Devel::SelfStubber> has been upgraded from version 1.03 to 1.05.
1433
1434=item *
1435
5076a392
FC
1436C<diagnostics> has been upgraded from version 1.19 to 1.22.
1437
1438It now renders pod links slightly better, and has been taught to find
1439descriptions for messages that share their descriptions with other
1440messages.
1441
1442=item *
1443
1444C<Digest::MD5> has been upgraded from version 2.39 to 2.51.
1445
1446It is now safe to use this module in combination with threads.
1447
1448=item *
1449
1450C<Digest::SHA> has been upgraded from version 5.47 to 5.61.
1451
1452C<shasum> now more closely mimics C<sha1sum>/C<md5sum>.
1453
1454C<Addfile> accepts all POSIX filenames.
1455
1984204c
FC
1456New SHA-512/224 and SHA-512/256 transforms (ref. NIST Draft FIPS 180-4
1457[February 2011])
5076a392
FC
1458
1459=item *
1460
88410521
FR
1461C<DirHandle> has been upgraded from version 1.03 to 1.04.
1462
1463=item *
1464
e53cbaa3
FR
1465C<Dumpvalue> has been upgraded from version 1.13 to 1.16.
1466
1467=item *
1468
31e8b85a 1469C<DynaLoader> has been upgraded from version 1.10 to 1.13.
5076a392
FC
1470
1471It fixes a buffer overflow when passed a very long file name.
1472
1473It no longer inherits from AutoLoader; hence it no longer
1474produces weird error messages for unsuccessful method calls on classes that
1475inherit from DynaLoader [perl #84358].
1476
1477=item *
1478
1479C<Encode> has been upgraded from version 2.39 to 2.42.
1480
1481Now, all 66 Unicode non-characters are treated the same way U+FFFF has
1984204c
FC
1482always been treated; in cases when it was disallowed, all 66 are
1483disallowed; in those cases where it warned, all 66 warn.
5076a392
FC
1484
1485=item *
1486
68f90ac3
FR
1487C<Env> has been upgraded from version 1.01 to 1.02.
1488
1489=item *
1490
5076a392
FC
1491C<Errno> has been upgraded from version 1.11 to 1.13.
1492
1493The implementation of C<Errno> has been refactored to use about 55% less memory.
5076a392
FC
1494
1495On some platforms with unusual header files, like Win32/gcc using mingw64
1496headers, some constants which weren't actually error numbers have been exposed
1497by C<Errno>. This has been fixed [perl #77416].
1498
1499=item *
1500
1501C<Exporter> has been upgraded from version 5.64_01 to 5.64_03.
1502
1503Exporter no longer overrides C<$SIG{__WARN__}> [perl #74472]
1504
1505=item *
1506
25fe7f8f
FR
1507C<ExtUtils::CBuilder> has been upgraded from version 0.27 to 0.280202.
1508
1509=item *
1510
2292e71e
FR
1511C<ExtUtils::Command> has been upgraded from version 1.16 to 1.17.
1512
1513=item *
1514
5076a392
FC
1515C<ExtUtils::Constant> has been upgraded from 0.22 to 0.23.
1516
1517The C<AUTOLOAD> helper code generated by C<ExtUtils::Constant::ProxySubs>
1518can now C<croak> for missing constants, or generate a complete C<AUTOLOAD>
1984204c
FC
1519subroutine in XS, allowing simplification of many modules that use it
1520(C<Fcntl>, C<File::Glob>, C<GDBM_File>, C<I18N::Langinfo>, C<POSIX>,
1521C<Socket>).
5076a392
FC
1522
1523C<ExtUtils::Constant::ProxySubs> can now optionally push the names of all
1984204c 1524constants onto the package's C<@EXPORT_OK>.
5076a392
FC
1525
1526=item *
1527
588c5853
FR
1528C<ExtUtils::Install> has been upgraded from version 1.55 to 1.56.
1529
1530=item *
1531
5418ffb3
FR
1532C<ExtUtils::MakeMaker> has been upgraded from version 6.56 to 6.57_05.
1533
1534=item *
1535
f40ab45f
FR
1536C<ExtUtils::Manifest> has been upgraded from version 1.57 to 1.58.
1537
1538=item *
1539
10fb15d2 1540C<ExtUtils::ParseXS> has been upgraded from version 2.21 to 2.2210.
b7064dd7
FR
1541
1542=item *
1543
8b87be80 1544C<Fcntl> has been upgraded from version 1.06 to 1.11.
26f7fa64
FR
1545
1546=item *
1547
1548C<File::Basename> has been upgraded from version 2.78 to 2.81.
8b87be80
FR
1549
1550=item *
1551
05102622
FR
1552C<File::CheckTree> has been upgraded from version 4.4 to 4.41.
1553
1554=item *
1555
65d78858
FR
1556C<File::Copy> has been upgraded from version 2.17 to 2.21.
1557
1558=item *
1559
e12786fa 1560C<File::DosGlob> has been upgraded from version 1.01 to 1.04.
5076a392
FC
1561
1562It allows patterns containing literal parentheses (they no longer need to
1984204c
FC
1563be escaped). On Windows, it no longer
1564adds an extra F<./> to the file names
5076a392
FC
1565returned when the pattern is a relative glob with a drive specification,
1566like F<c:*.pl> [perl #71712].
1567
1568=item *
1569
1570C<File::Fetch> has been upgraded from version 0.24 to 0.32.
1571
1572C<HTTP::Lite> is now supported for 'http' scheme.
1573
1574The C<fetch> utility is supported on FreeBSD, NetBSD and
1575Dragonfly BSD for the C<http> and C<ftp> schemes.
1576
1577=item *
1578
23f2cbb1 1579C<File::Find> has been upgraded from version 1.15 to 1.19.
5076a392 1580
1984204c 1581It improves handling of backslashes on Windows, so that paths like
5076a392
FC
1582F<c:\dir\/file> are no longer generated [perl #71710].
1583
1584=item *
1585
0ae9f678
FR
1586C<File::Glob> has been upgraded from version 1.07 to 1.12.
1587
1588=item *
1589
d430b8e7
FC
1590C<File::Spec> has been upgraded from version 3.31 to 3.33.
1591
1592Several portability fixes were made in C<File::Spec::VMS>: a colon is now
1593recognized as a delimiter in native filespecs; caret-escaped delimiters are
1594recognized for better handling of extended filespecs; C<catpath()> returns
1595an empty directory rather than the current directory if the input directory
1596name is empty; C<abs2rel()> properly handles Unix-style input (5.12.2).
1597
1598=item *
1599
46ba0657 1600C<File::stat> has been upgraded from 1.02 to 1.05.
5076a392
FC
1601
1602The C<-x> and C<-X> file test operators now work correctly under the root
1603user.
1604
1605=item *
1606
b7edcc3c
FR
1607C<Filter::Simple> has been upgraded from version 0.84 to 0.86.
1608
1609=item *
1610
dc6857fd 1611C<GDBM_File> has been upgraded from 1.10 to 1.14.
5076a392
FC
1612
1613This fixes a memory leak when DBM filters are used.
1614
1615=item *
1616
6e107b45 1617C<Hash::Util> has been upgraded from 0.07 to 0.11.
5076a392 1618
1984204c
FC
1619Hash::Util no longer emits spurious "uninitialized" warnings when
1620recursively locking hashes that have undefined values [perl #74280].
5076a392
FC
1621
1622=item *
1623
89ce9b34
FR
1624C<Hash::Util::FieldHash> has been upgraded from version 1.04 to 1.09.
1625
1626=item *
1627
eec33fe6
FR
1628C<I18N::Collate> has been upgraded from version 1.01 to 1.02.
1629
1630=item *
1631
ad5f8f47 1632C<I18N::Langinfo> has been upgraded from version 0.03 to 0.08.
5076a392
FC
1633
1634C<langinfo()> now defaults to using C<$_> if there is no argument given, just
5334145a 1635as the documentation has always claimed.
5076a392
FC
1636
1637=item *
1638
c41635f7
FR
1639C<I18N::LangTags> has been upgraded from version 0.35 to 0.35_01.
1640
1641=item *
1642
98a6a4ff
FR
1643C<if> has been upgraded from version 0.05 to 0.0601.
1644
1645=item *
1646
f6ff7fb6
FR
1647C<IO> has been upgraded from version 1.25_02 to 1.25_04.
1648
582bf58c
FR
1649This version of C<IO> includes a new C<IO::Select>, which now allows IO::Handle
1650objects (and objects in derived classes) to be removed from an IO::Select set
1651even if the underlying file descriptor is closed or invalid.
5076a392
FC
1652
1653=item *
1654
d07561d3 1655C<IPC::Cmd> has been upgraded from version 0.54 to 0.70.
5076a392 1656
1984204c
FC
1657Resolves an issue with splitting Win32 command lines. An argument
1658consisting of the single character "0" used to be omitted (CPAN RT #62961).
5076a392
FC
1659
1660=item *
1661
3f16e4eb 1662C<IPC::Open3> has been upgraded from 1.05 to 1.09.
5076a392 1663
4ed2cea4
FC
1664C<open3> now produces an error if the C<exec> call fails, allowing this
1665condition to be distinguished from a child process that exited with a
1666non-zero status [perl #72016].
1667
5076a392
FC
1668The internal C<xclose> routine now knows how to handle file descriptors, as
1669documented, so duplicating STDIN in a child process using its file
1670descriptor now works [perl #76474].
1671
1672=item *
1673
c8b41807
FR
1674C<IPC::SysV> has been upgraded from version 2.01 to 2.03.
1675
1676=item *
1677
ef79f038
FR
1678C<lib> has been upgraded from version 0.62 to 0.63.
1679
1680=item *
1681
5b1884f4 1682C<Locale::Maketext> has been upgraded from version 1.14 to 1.19.
5076a392 1683
1984204c 1684Locale::Maketext now supports external caches.
5076a392 1685
1984204c
FC
1686This upgrade also fixes an infinite loop in
1687C<Locale::Maketext::Guts::_compile()> when
5076a392
FC
1688working with tainted values (CPAN RT #40727).
1689
1984204c 1690C<< ->maketext >> calls will now back up and restore C<$@> so that error
5076a392
FC
1691messages are not suppressed (CPAN RT #34182).
1692
1693=item *
1694
3811bd2b
FR
1695C<Log::Message> has been upgraded from version 0.02 to 0.04.
1696
1697=item *
1698
8eb65377
FR
1699C<Log::Message::Simple> has been upgraded from version 0.06 to 0.08.
1700
1701=item *
1702
5076a392
FC
1703C<Math::BigInt> has been upgraded from version 1.89_01 to 1.994.
1704
1705This fixes, among other things, incorrect results when computing binomial
1706coefficients [perl #77640].
1707
1984204c 1708It also prevents C<sqrt($int)> from crashing under C<use bigrat;>
5076a392
FC
1709[perl #73534].
1710
1711=item *
1712
846c1cec
FR
1713C<Math::BigInt::FastCalc> has been upgraded from version 0.19 to 0.28.
1714
1715=item *
1716
fce4aef3
FR
1717C<Math::BigRat> has been upgraded from version 0.24 to 0.26_02.
1718
1719=item *
1720
12e26027
FR
1721C<Memoize> has been upgraded from version 1.01_03 to 1.02.
1722
1723=item *
1724
5076a392
FC
1725C<MIME::Base64> has been upgraded from 3.08 to 3.13.
1726
1727Includes new functions to calculate the length of encoded and decoded
1728base64 strings.
1729
1730Now provides C<encode_base64url> and C<decode_base64url> functions to process
1731the base64 scheme for "URL applications".
1732
1733=item *
1734
1735C<Module::Build> has been upgraded from version 0.3603 to 0.3800.
1736
1737A notable change is the deprecation of several modules.
1738Module::Build::Version has been deprecated and Module::Build now relies
1739directly upon L<version>. Module::Build::ModuleInfo has been deprecated in
1740favor of a standalone copy of it called L<Module::Metadata>.
1741Module::Build::YAML has been deprecated in favor of L<CPAN::Meta::YAML>.
1742
1743Module::Build now also generates META.json and MYMETA.json files
1744in accordance with version 2 of the CPAN distribution metadata specification,
1745L<CPAN::Meta::Spec>. The older format META.yml and MYMETA.yml files are
1746still generated, as well.
1747
1748=item *
1749
7259fe26 1750C<Module::CoreList> has been upgraded from version 2.29 to 2.47.
5076a392
FC
1751
1752Besides listing the updated core modules of this release, it also stops listing
1984204c 1753the C<Filespec> module. That module never existed in core. The scripts
5076a392 1754generating C<Module::CoreList> confused it with C<VMS::Filespec>, which actually
1984204c 1755is a core module as of perl 5.8.7.
5076a392
FC
1756
1757=item *
1758
193af05b
FR
1759C<Module::Load> has been upgraded from version 0.16 to 0.18.
1760
1761=item *
1762
5b3a054f
FR
1763C<Module::Load::Conditional> has been upgraded from version 0.34 to 0.44.
1764
1765=item *
1766
01835e3a
FR
1767C<mro> has been upgraded from version 1.02 to 1.07.
1768
1769=item *
1770
bfe7bf96 1771C<NDBM_File> has been upgraded from version 1.08 to 1.12.
4f978a3b
FR
1772
1773This fixes a memory leak when DBM filters are used.
1774
1775=item *
1776
d0aa5c91
FR
1777C<Net::Ping> has been upgraded from version 2.36 to 2.38.
1778
1779=item *
1780
d44b8a8c
FR
1781C<NEXT> has been upgraded from version 0.64 to 0.65.
1782
1783=item *
1784
678d4fd4
FR
1785C<Object::Accessor> has been upgraded from version 0.36 to 0.38.
1786
1787=item *
1788
34188656 1789C<ODBM_File> have been upgraded from version 1.07 to 1.10.
5076a392
FC
1790
1791This fixes a memory leak when DBM filters are used.
1792
1793=item *
1794
4c69840c
FR
1795C<Opcode> has been upgraded from version 1.15 to 1.18.
1796
1797=item *
1798
f4c5ae54 1799C<overload> has been upgraded from 1.10 to 1.13.
5076a392
FC
1800
1801C<overload::Method> can now handle subroutines that are themselves blessed
1802into overloaded classes [perl #71998].
1803
5076a392
FC
1804The documentation has greatly improved. See L</Documentation> below.
1805
1806=item *
1807
f84c796e
FR
1808C<Params::Check> has been upgraded from version 0.26 to 0.28.
1809
1810=item *
1811
550ee92b
FR
1812C<parent> has been upgraded from version 0.223 to 0.225.
1813
1814=item *
1815
5076a392
FC
1816C<Parse::CPAN::Meta> has been upgraded from version 1.40 to 1.4401.
1817
1984204c 1818The latest Parse::CPAN::Meta can now read YAML and JSON files using
5076a392
FC
1819L<CPAN::Meta::YAML> and L<JSON::PP>, which are now part of the Perl core.
1820
1821=item *
1822
e981cf86
FR
1823C<PerlIO::encoding> has been upgraded from version 0.12 to 0.14.
1824
1825=item *
1826
5076a392
FC
1827C<PerlIO::scalar> has been upgraded from 0.07 to 0.11.
1828
1829A C<read> after a C<seek> beyond the end of the string no longer thinks it
1830has data to read [perl #78716].
1831
1832=item *
1833
776f733b
FR
1834C<PerlIO::via> has been upgraded from version 0.09 to 0.11.
1835
1836=item *
1837
ae9456cc
FR
1838C<Pod::Html> has been upgraded from version 1.09 to 1.1.
1839
1840=item *
1841
be3c8498
FR
1842C<Pod::LaTeX> has been upgraded from version 0.58 to 0.59.
1843
1844=item *
1845
fd8a2e89
FR
1846C<Pod::Perldoc> has been upgraded from version 3.15_02 to 3.15_03.
1847
1848=item *
1849
5bcb6583
FR
1850C<Pod::Simple> has been upgraded from version 3.13 to 3.16.
1851
1852=item *
1853
abb8c779 1854C<POSIX> has been upgraded from 1.19 to 1.24.
5076a392
FC
1855
1856It now includes constants for POSIX signal constants.
1857
1858=item *
1859
1984204c 1860C<re> has been upgraded from version 0.11 to 0.17.
5076a392
FC
1861
1862New C<use re "/flags"> pragma
1863
5076a392 1864The C<regmust> function used to crash when called on a regular expression
1984204c 1865belonging to a pluggable engine. Now it croaks instead.
5076a392
FC
1866
1867C<regmust> no longer leaks memory.
1868
1869=item *
1870
1871C<Safe> has been upgraded from version 2.25 to 2.29.
1872
cdc10f43
FC
1873Coderefs returned by C<reval()> and C<rdo()> are now wrapped via
1874C<wrap_code_refs> (5.12.1).
1875
5076a392
FC
1876This fixes a possible infinite loop when looking for coderefs.
1877
cdc10f43 1878It adds several version::vxs::* routines to the default share.
5076a392
FC
1879
1880=item *
1881
2c19fa42
FR
1882C<SDBM_File> has been upgraded from version 1.06 to 1.09.
1883
1884=item *
1885
5076a392
FC
1886C<SelfLoader> has been upgraded from 1.17 to 1.18.
1887
1888It now works in taint mode [perl #72062].
1889
1890=item *
1891
1892C<sigtrap> has been upgraded from version 1.04 to 1.05.
1893
1894It no longer tries to modify read-only arguments when generating a
1895backtrace [perl #72340].
1896
1897=item *
1898
1984204c 1899C<Socket> has been upgraded from version 1.87 to 1.94.
5076a392 1900
1984204c 1901See L</IPv6 support>, above.
5076a392
FC
1902
1903=item *
1904
1905C<Storable> has been upgraded from version 2.22 to 2.27.
1906
1907Includes performance improvement for overloaded classes.
1908
5076a392 1909This adds support for serialising code references that contain UTF-8 strings
1984204c
FC
1910correctly. The Storable minor version
1911number changed as a result, meaning that
5076a392
FC
1912Storable users who set C<$Storable::accept_future_minor> to a C<FALSE> value
1913will see errors (see L<Storable/FORWARD COMPATIBILITY> for more details).
1914
1915Freezing no longer gets confused if the Perl stack gets reallocated
1916during freezing [perl #80074].
1917
1918=item *
1919
648c3d7d
FR
1920C<Sys::Hostname> has been upgraded from version 1.11 to 1.16.
1921
1922=item *
1923
90c6e78f
FR
1924C<Term::ANSIColor> has been upgraded from version 2.02 to 3.00.
1925
1926=item *
1927
d9f2f059
FR
1928C<Term::UI> has been upgraded from version 0.20 to 0.26.
1929
1930=item *
1931
80ebb519
FR
1932C<Test::Harness> has been upgraded from version 3.17 to 3.23.
1933
1934=item *
1935
5076a392
FC
1936C<Test::Simple> has been upgraded from version 0.94 to 0.98.
1937
1938Among many other things, subtests without a C<plan> or C<no_plan> now have an
1939implicit C<done_testing()> added to them.
1940
1941=item *
1942
5076a392
FC
1943C<Thread::Semaphore> has been upgraded from version 2.09 to 2.12.
1944
1984204c
FC
1945It provides two new methods that give more control over the decrementing of
1946semaphores: C<down_nb> and C<down_force>.
5076a392
FC
1947
1948=item *
1949
f0d895e1
FR
1950C<Thread::Queue> has been upgraded from version 2.11 to 2.12.
1951
1952=item *
1953
1a6b954e
FR
1954C<threads> has been upgraded from version 1.75 to 1.83.
1955
1956=item *
1957
55816daa
FR
1958C<threads::shared> has been upgraded from version 1.32 to 1.36.
1959
1960=item *
1961
5076a392
FC
1962C<Tie::Hash> has been upgraded from version 1.03 to 1.04.
1963
1964Calling C<< Tie::Hash-E<gt>TIEHASH() >> used to loop forever. Now it C<croak>s.
1965
1966=item *
1967
f2adc546
FR
1968C<Tie::Hash::NamedCapture> has been upgraded from version 0.06 to 0.08.
1969
1970=item *
1971
ed68b07e
FR
1972C<Tie::RefHash> has been upgraded from version 1.38 to 1.39.
1973
1974=item *
1975
bb3c221a
FR
1976C<Time::HiRes> has been upgraded from version 1.9719 to 1.9721_01.
1977
1978=item *
1979
97fa568b
FR
1980C<Time::Local> has been upgraded from version 1.1901_01 to 1.2000.
1981
1982=item *
1983
a83cb732
FR
1984C<Time::Piece> has been upgraded from version 1.15_01 to 1.20_01.
1985
1986=item *
1987
5076a392
FC
1988C<Unicode::Collate> has been upgraded from version 0.52_01 to 0.73.
1989
1984204c 1990Unicode::Collate has been updated to use Unicode 6.0.0.
5076a392 1991
1984204c
FC
1992Unicode::Collate::Locale now supports a plethora of new locales: ar, be,
1993bg, de__phonebook, hu, hy, kk, mk, nso, om, tn, vi, hr, ig, ja, ko, ru, sq,
1994se, sr, to, uk, zh, zh__big5han, zh__gb2312han, zh__pinyin and zh__stroke.
5076a392
FC
1995
1996The following modules have been added:
1997
1998C<Unicode::Collate::CJK::Big5> for C<zh__big5han> which makes
1999tailoring of CJK Unified Ideographs in the order of CLDR's big5han ordering.
2000
2001C<Unicode::Collate::CJK::GB2312> for C<zh__gb2312han> which makes
2002tailoring of CJK Unified Ideographs in the order of CLDR's gb2312han ordering.
2003
2004C<Unicode::Collate::CJK::JISX0208> which makes tailoring of 6355 kanji
2005(CJK Unified Ideographs) in the JIS X 0208 order.
2006
2007C<Unicode::Collate::CJK::Korean> which makes tailoring of CJK Unified Ideographs
2008in the order of CLDR's Korean ordering.
2009
2010C<Unicode::Collate::CJK::Pinyin> for C<zh__pinyin> which makes
2011tailoring of CJK Unified Ideographs in the order of CLDR's pinyin ordering.
2012
2013C<Unicode::Collate::CJK::Stroke> for C<zh__stroke> which makes
2014tailoring of CJK Unified Ideographs in the order of CLDR's stroke ordering.
2015
5076a392
FC
2016This also sees the switch from using the pure-perl version of this
2017module to the XS version.
2018
2019=item *
2020
ec52b54b
FR
2021C<Unicode::Normalize> has been upgraded from version 1.03 to 1.10.
2022
2023=item *
2024
5076a392
FC
2025C<Unicode::UCD> has been upgraded from version 0.27 to 0.32.
2026
1984204c
FC
2027A new function, C<Unicode::UCD::num()>, has been added. This function
2028returns the numeric value of the string passed it or C<undef> if the string
2029in its entirety has no "safe" numeric value. (For more detail, and for the
2030definition of "safe", see L<Unicode::UCD/num>.)
5076a392 2031
1984204c 2032This upgrade also includes a number of bug fixes:
5076a392
FC
2033
2034=over 4
2035
2036=item charinfo()
2037
2038=over 4
2039
2040=item *
2041
2042It is now updated to Unicode Version 6 with Corrigendum #8, except,
2043as with Perl 5.14, the code point at U+1F514 has no name.
2044
2045=item *
2046
2047The Hangul syllable code points have the correct names, and their
2048decompositions are always output without requiring L<Lingua::KO::Hangul::Util>
2049to be installed.
2050
2051=item *
2052
54c7bb16
FC
2053The CJK (Chinese-Japanese-Korean) code points U+2A700 to U+2B734
2054and U+2B740 to U+2B81D are now properly handled.
5076a392
FC
2055
2056=item *
2057
2058The numeric values are now output for those CJK code points that have them.
2059
2060=item *
2061
2062The names that are output for code points with multiple aliases are now the
2063corrected ones.
2064
2065=back
2066
2067=item charscript()
2068
2069This now correctly returns "Unknown" instead of C<undef> for the script
2070of a code point that hasn't been assigned another one.
2071
2072=item charblock()
2073
2074This now correctly returns "No_Block" instead of C<undef> for the block
2075of a code point that hasn't been assigned to another one.
2076
2077=back
2078
5076a392
FC
2079=item *
2080
2081C<version> has been upgraded from 0.82 to 0.88.
2082
1984204c 2083Due to a bug, now fixed, the C<is_strict> and C<is_lax> functions did not
cdc10f43 2084work when exported (5.12.1).
5076a392
FC
2085
2086=item *
2087
3e625598 2088C<warnings> has been upgraded from version 1.09 to 1.12.
5076a392
FC
2089
2090Calling C<use warnings> without arguments is now significantly more efficient.
2091
4f978a3b
FR
2092=item *
2093
2094C<warnings::register> have been upgraded from version 1.01 to 1.02.
2095
5076a392
FC
2096It is now possible to register warning categories other than the names of
2097packages using C<warnings::register>. See L<perllexwarn> for more information.
2098
2099=item *
2100
62e270c2
FR
2101C<XSLoader> has been upgraded from version 0.10 to 0.13.
2102
2103=item *
2104
5076a392
FC
2105C<VMS::DCLsym> has been upgraded from version 1.03 to 1.05.
2106
2107Two bugs have been fixed [perl #84086]:
2108
2109The symbol table name was lost when tying a hash, due to a thinko in
2110C<TIEHASH>. The result was that all tied hashes interacted with the
2111local symbol table.
2112
2113Unless a symbol table name had been explicitly specified in the call
2114to the constructor, querying the special key ':LOCAL' failed to
2115identify objects connected to the local symbol table.
2116
2117=item *
2118
2119C<Win32> has been upgraded from version 0.39 to 0.44.
2120
1984204c
FC
2121This release has several new functions: C<Win32::GetSystemMetrics>,
2122C<Win32::GetProductInfo>, C<Win32::GetOSDisplayName>.
5076a392 2123
1984204c
FC
2124The names returned by C<Win32::GetOSName> and C<Win32::GetOSDisplayName>
2125have been corrected.
5076a392 2126
3bbe5383
FR
2127=item *
2128
2129C<XS::Typemap> has been upgraded from version 0.03 to 0.05.
2130
5076a392
FC
2131=back
2132
5076a392
FC
2133=head2 Removed Modules and Pragmata
2134
2135The following modules have been removed from the core distribution, and if
2136needed should be installed from CPAN instead.
2137
2138=over
2139
4f978a3b
FR
2140=item *
2141
2142C<Class::ISA> has been removed from the Perl core. Prior version was 0.36.
5076a392 2143
4f978a3b
FR
2144=item *
2145
2146C<Pod::Plainer> has been removed from the Perl core. Prior version was 1.02.
2147
2148=item *
5076a392 2149
4f978a3b 2150C<Switch> has been removed from the Perl core. Prior version was 2.16.
5076a392
FC
2151
2152=back
2153
2154The removal of C<Shell> has been deferred until after 5.14, as the
2155implementation of C<Shell> shipped with 5.12.0 did not correctly issue the
2156warning that it was to be removed from core.
2157
2158=head1 Documentation
2159
5076a392
FC
2160=head2 New Documentation
2161
41e29def 2162=head3 L<perlgpl>
5076a392
FC
2163
2164L<perlgpl> has been updated to contain GPL version 1, as is included in the
cdc10f43 2165F<README> distributed with perl (5.12.1).
5076a392 2166
41e29def 2167=head3 Perl 5.12.x delta files
5076a392 2168
41e29def
FC
2169The perldelta files for Perl 5.12.1 to 5.12.3 have been added from the
2170maintenance branch: L<perl5121delta>, L<perl5122delta>, L<perl5123delta>.
5076a392
FC
2171
2172=head3 L<perlpodstyle>
2173
2174New style guide for POD documentation,
2175split mostly from the NOTES section of the pod2man man page.
2176
41e29def
FC
2177=head3 L<perlsource>, L<perlinterp>, L<perlhacktut>, and L<perlhacktips>
2178
cc13eef1 2179See L</perlhack and perlrepository revamp>, below.
5076a392
FC
2180
2181=head2 Changes to Existing Documentation
2182
41e29def 2183=head3 L<perlmodlib> is now complete
4ed2cea4
FC
2184
2185The perlmodlib page that came with Perl 5.12.0 was missing a lot of
2186modules, due to a bug in the script that generates the list. This has been
cdc10f43 2187fixed [perl #74332] (5.12.1).
4ed2cea4 2188
41e29def 2189=head3 Replace wrong tr/// table in L<perlebcdic>
5076a392 2190
41e29def 2191L<perlebcdic> contains a helpful table to use in tr/// to convert
5076a392
FC
2192between EBCDIC and Latin1/ASCII. Unfortunately, the table was the
2193inverse of the one it describes, though the code that used the table
2194worked correctly for the specific example given.
2195
2196The table has been changed to its inverse, and the sample code changed
2197to correspond, as this is easier for the person trying to follow the
2198instructions since deriving the old table is somewhat more complicated.
2199
2200The table has also been changed to hex from octal, as that is more the norm
2201these days, and the recipes in the pod altered to print out leading
41e29def 2202zeros to make all the values the same length.
5076a392 2203
41e29def 2204=head3 Tricks for user-defined casing
5076a392 2205
41e29def
FC
2206L<perlunicode> now contains an explanation of how to override, mangle
2207and otherwise tweak the way perl handles upper-, lower- and other-case
2208conversions on Unicode data, and how to provide scoped changes to alter
2209one's own code's behaviour without stomping on anybody else.
5076a392
FC
2210
2211=head3 INSTALL explicitly states the requirement for C89
2212
d430b8e7
FC
2213This was already true but it's now Officially Stated For The Record
2214(5.12.2).
5076a392 2215
41e29def 2216=head3 Explanation of C<\xI<HH>> and C<\oI<OOO>> escapes
5076a392 2217
41e29def
FC
2218L<perlop> has been updated with more detailed explanation of these two
2219character escapes.
5076a392 2220
41e29def 2221=head3 C<-0I<NNN>> switch
5076a392 2222
41e29def 2223In L<perlrun>, the behavior of the C<-0NNN> switch for C<-0400> or higher
d430b8e7 2224has been clarified (5.12.2).
5076a392 2225
cdc10f43
FC
2226=head3 Maintenance policy
2227
2228L<perlpolicy> now contains the policy on what patches are acceptable for
2229maintenance branches (5.12.1).
2230
41e29def 2231=head3 Deprecation policy
5076a392 2232
41e29def 2233L<perlpolicy> now contains the policy on compatibility and deprecation
d430b8e7 2234along with definitions of terms like "deprecation" (5.12.2).
5076a392 2235
41e29def 2236=head3 New descriptions in L<perldiag>
5076a392
FC
2237
2238The following existing diagnostics are now documented:
2239
2240=over 4
2241
2242=item *
2243
2244L<Ambiguous use of %c resolved as operator %c|perldiag/"Ambiguous use of %c resolved as operator %c">
2245
2246=item *
2247
2248L<Ambiguous use of %c{%s} resolved to %c%s|perldiag/"Ambiguous use of %c{%s} resolved to %c%s">
2249
2250=item *
2251
2252L<Ambiguous use of %c{%s%s} resolved to %c%s%s|perldiag/"Ambiguous use of %c{%s%s} resolved to %c%s%s">
2253
2254=item *
2255
2256L<Ambiguous use of -%s resolved as -&%s()|perldiag/"Ambiguous use of -%s resolved as -&%s()">
2257
2258=item *
2259
2260L<Invalid strict version format (%s)|perldiag/"Invalid strict version format (%s)">
2261
2262=item *
2263
2264L<Invalid version format (%s)|perldiag/"Invalid version format (%s)">
2265
2266=item *
2267
2268L<Invalid version object|perldiag/"Invalid version object">
2269
2270=back
2271
5076a392
FC
2272=head3 L<perlbook>
2273
41e29def 2274L<perlbook> has been expanded to cover many more popular books.
5076a392 2275
41e29def 2276=head3 C<SvTRUE> macro
5076a392 2277
41e29def
FC
2278The documentation for the C<SvTRUE> macro in
2279L<perlapi> was simply wrong in stating that
5076a392
FC
2280get-magic is not processed. It has been corrected.
2281
41e29def 2282=head3 L<perlvar> revamp
5076a392 2283
41e29def 2284L<perlvar> reorders the variables and groups them by topic. Each variable
5076a392 2285introduced after Perl 5.000 notes the first version in which it is
41e29def 2286available. L<perlvar> also has a new section for deprecated variables to
5076a392
FC
2287note when they were removed.
2288
41e29def 2289=head3 Array and hash slices in scalar context
5076a392 2290
41e29def 2291These are now documented in L<perldata>.
5076a392 2292
41e29def 2293=head3 C<use locale> and formats
5076a392
FC
2294
2295L<perlform> and L<perllocale> have been corrected to state that
2296C<use locale> affects formats.
2297
5076a392
FC
2298=head3 L<overload>
2299
5076a392
FC
2300L<overload>'s documentation has practically undergone a rewrite. It
2301is now much more straightforward and clear.
2302
cc13eef1 2303=head3 perlhack and perlrepository revamp
5076a392
FC
2304
2305The L<perlhack> and perlrepository documents have been heavily edited and
2306split up into several new documents.
2307
2308The L<perlhack> document is now much shorter, and focuses on the Perl 5
2309development process and submitting patches to Perl. The technical content has
2310been moved to several new documents, L<perlsource>, L<perlinterp>,
2311L<perlhacktut>, and L<perlhacktips>. This technical content has only been
2312lightly edited.
2313
2314The perlrepository document has been renamed to L<perlgit>. This new document
2315is just a how-to on using git with the Perl source code. Any other content
2316that used to be in perlrepository has been moved to perlhack.
2317
41e29def 2318=head3 Time::Piece examples
5076a392
FC
2319
2320Examples in L<perlfaq4> have been updated to show the use of
41e29def 2321L<Time::Piece>.
5076a392
FC
2322
2323=head1 Diagnostics
2324
2325The following additions or changes have been made to diagnostic output,
2326including warnings and fatal error messages. For the complete list of
2327diagnostic messages, see L<perldiag>.
2328
2329=head2 New Diagnostics
2330
a593b319
FC
2331=head3 New Errors
2332
5076a392
FC
2333=over
2334
a593b319 2335=item Closure prototype called
5076a392 2336
a593b319
FC
2337This error occurs when a subroutine reference passed to an attribute
2338handler is called, if the subroutine is a closure [perl #68560].
5076a392 2339
a593b319 2340=item Insecure user-defined property %s
5076a392 2341
a593b319
FC
2342Perl detected tainted data when trying to compile a regular
2343expression that contains a call to a user-defined character property
2344function, i.e. C<\p{IsFoo}> or C<\p{InFoo}>.
2345See L<perlunicode/User-Defined Character Properties> and L<perlsec>.
5076a392 2346
a593b319 2347=item panic: gp_free failed to free glob pointer - something is repeatedly re-creating entries
5076a392 2348
a593b319
FC
2349This new error is triggered if a destructor called on an object in a
2350typeglob that is being freed creates a new typeglob entry containing an
2351object with a destructor that creates a new entry containing an object....
5076a392 2352
a593b319 2353=item Parsing code internal error (%s)
5076a392 2354
a593b319
FC
2355This new fatal error is produced when parsing
2356code supplied by an extension violates the
2357parser's API in a detectable way.
5076a392 2358
a593b319 2359=item refcnt: fd %d%s
5076a392 2360
a593b319
FC
2361This new error only occurs if a internal consistency check fails when a
2362pipe is about to be closed.
5076a392 2363
a593b319 2364=item Regexp modifier "/%c" may not appear twice
5076a392 2365
a593b319
FC
2366The regular expression pattern has one of the
2367mutually exclusive modifiers repeated.
5076a392 2368
a593b319 2369=item Regexp modifiers "/%c" and "/%c" are mutually exclusive
5076a392 2370
a593b319
FC
2371The regular expression pattern has more than one of the mutually
2372exclusive modifiers.
5076a392 2373
a593b319 2374=item Using !~ with %s doesn't make sense
5076a392 2375
a593b319 2376This error occurs when C<!~> is used with C<s///r> or C<y///r>.
5076a392 2377
a593b319 2378=back
5076a392 2379
a593b319 2380=head3 New Warnings
5076a392 2381
a593b319 2382=over
5076a392 2383
a593b319 2384=item "\b{" is deprecated; use "\b\{" instead
5076a392 2385
a593b319 2386=item "\B{" is deprecated; use "\B\{" instead
5076a392 2387
a593b319
FC
2388Use of an unescaped "{" immediately following a C<\b> or C<\B> is now
2389deprecated so as to reserve its use for Perl itself in a future release.
5076a392 2390
a593b319 2391=item Operation "%s" returns its argument for ...
5076a392 2392
a593b319
FC
2393Performing an operation requiring Unicode semantics (such as case-folding)
2394on a Unicode surrogate or a non-Unicode character now triggers a warning:
2395'Operation "%s" returns its argument for ...'.
5076a392 2396
a593b319
FC
2397=item Use of qw(...) as parentheses is deprecated
2398
2399See L</"Use of qw(...) as parentheses">, above, for details.
5076a392
FC
2400
2401=back
2402
2403=head2 Changes to Existing Diagnostics
2404
2405=over 4
2406
2407=item *
2408
4ed2cea4
FC
2409The "Variable $foo is not imported" warning that precedes a
2410C<strict 'vars'> error has now been assigned the "misc" category, so that
2411C<no warnings> will suppress it [perl #73712].
2412
2413=item *
2414
5076a392
FC
2415C<warn> and C<die> now produce 'Wide character' warnings when fed a
2416character outside the byte range if STDERR is a byte-sized handle.
2417
2418=item *
2419
2420The 'Layer does not match this perl' error message has been replaced with
a593b319 2421these more helpful messages [perl #73754]:
5076a392
FC
2422
2423=over 4
2424
2425=item *
2426
2427PerlIO layer function table size (%d) does not match size expected by this
2428perl (%d)
2429
2430=item *
2431
2432PerlIO layer instance size (%d) does not match size expected by this perl
2433(%d)
2434
2435=back
2436
5076a392
FC
2437=item *
2438
2439The "Found = in conditional" warning that is emitted when a constant is
2440assigned to a variable in a condition is now withheld if the constant is
2441actually a subroutine or one generated by C<use constant>, since the value
2442of the constant may not be known at the time the program is written
2443[perl #77762].
2444
2445=item *
2446
2447Previously, if none of the C<gethostbyaddr>, C<gethostbyname> and
2448C<gethostent> functions were implemented on a given platform, they would
2449all die with the message 'Unsupported socket function "gethostent" called',
2450with analogous messages for C<getnet*> and C<getserv*>. This has been
2451corrected.
2452
2453=item *
2454
a593b319
FC
2455The warning message about unrecognized regular expression escapes passed
2456through has been changed to include any literal '{' following the
2457two-character escape. E.g., "\q{" is now emitted instead of "\q".
5076a392
FC
2458
2459=back
2460
2461=head1 Utility Changes
2462
0b88cc74 2463=head3 L<perlbug>
5076a392
FC
2464
2465=over 4
2466
2467=item *
2468
0b88cc74
FC
2469L<perlbug> now looks in the EMAIL environment variable for a return address
2470if the REPLY-TO and REPLYTO variables are empty.
5076a392
FC
2471
2472=item *
2473
0b88cc74
FC
2474L<perlbug> did not previously generate a From: header, potentially
2475resulting in dropped mail. Now it does include that header.
5076a392
FC
2476
2477=item *
2478
0b88cc74 2479The user's address is now used as the return-path.
4ed2cea4 2480
0b88cc74
FC
2481Many systems these days don't have a valid Internet domain name and
2482perlbug@perl.org does not accept email with a return-path that does
2483not resolve. So the user's address is now passed to sendmail so it's
2484less likely to get stuck in a mail queue somewhere [perl #82996].
5076a392 2485
2c389f6c
FC
2486=item *
2487
d430b8e7
FC
2488L<perlbug> now always gives the reporter a chance to change the email
2489address it guesses for them (5.12.2).
2490
2491=item *
2492
2493L<perlbug> should no longer warn about uninitialized values when using the C<-d>
2494and C<-v> options (5.12.2).
2c389f6c 2495
5076a392
FC
2496=back
2497
0b88cc74 2498=head3 L<perl5db.pl>
5076a392 2499
0b88cc74 2500=over
5076a392
FC
2501
2502=item *
2503
0b88cc74
FC
2504The remote terminal works after forking and spawns new sessions - one
2505for each forked process.
5076a392
FC
2506
2507=back
2508
0b88cc74 2509=head3 L<ptargrep>
5076a392
FC
2510
2511=over 4
2512
2513=item *
2514
0b88cc74
FC
2515L<ptargrep> is a new utility to apply pattern matching to the contents of
2516files in a tar archive. It comes with C<Archive::Tar>.
5076a392
FC
2517
2518=back
2519
2520=head1 Configuration and Compilation
2521
61752d82
FC
2522See also L</"Naming fixes in Policy_sh.SH may invalidate Policy.sh">,
2523above.
2524
5076a392
FC
2525=over 4
2526
2527=item *
2528
87595b22
FC
2529CCINCDIR and CCLIBDIR for the mingw64
2530cross-compiler are now correctly under
5076a392
FC
2531$(CCHOME)\mingw\include and \lib rather than immediately below $(CCHOME).
2532
5076a392
FC
2533This means the 'incpath', 'libpth', 'ldflags', 'lddlflags' and
2534'ldflags_nolargefiles' values in Config.pm and Config_heavy.pl are now
87595b22 2535set correctly.
5076a392
FC
2536
2537=item *
2538
87595b22
FC
2539'make test.valgrind' has been adjusted to account for cpan/dist/ext
2540separation.
5076a392
FC
2541
2542=item *
2543
2544On compilers that support it, C<-Wwrite-strings> is now added to cflags by
2545default.
2546
2547=item *
2548
2549The C<Encode> module can now (once again) be included in a static Perl
2550build. The special-case handling for this situation got broken in Perl
25515.11.0, and has now been repaired.
2552
1e463951
FC
2553=item *
2554
2555The previous default size of a PerlIO buffer (4096 bytes) has been increased
2556to the larger of 8192 bytes and your local BUFSIZ. Benchmarks show that doubling
2557this decade-old default increases read and write performance in the neighborhood
2558of 25% to 50% when using the default layers of perlio on top of unix. To choose
2559a non-default size, such as to get back the old value or to obtain an even
2560larger value, configure with:
2561
2562 ./Configure -Accflags=-DPERLIOBUF_DEFAULT_BUFSIZ=N
2563
2564where N is the desired size in bytes; it should probably be a multiple of
2565your page size.
2566
d430b8e7
FC
2567=item *
2568
2569An "incompatible operand types" error in ternary expressions when building
2570with C<clang> has been fixed (5.12.2).
2571
2572=item *
2573
2574Perl now skips setuid C<File::Copy> tests on partitions it detects to be mounted
2575as C<nosuid> (5.12.2).
2576
5076a392
FC
2577=back
2578
5076a392
FC
2579=head1 Platform Support
2580
5076a392
FC
2581=head2 New Platforms
2582
5076a392
FC
2583=over 4
2584
2585=item AIX
2586
cdc10f43 2587Perl now builds on AIX 4.2 (5.12.1).
5076a392
FC
2588
2589=back
2590
2591=head2 Discontinued Platforms
2592
2593=over 4
2594
5076a392
FC
2595=item Apollo DomainOS
2596
2597The last vestiges of support for this platform have been excised from the
2598Perl distribution. It was officially discontinued in version 5.12.0. It had
2599not worked for years before that.
2600
2601=item MacOS Classic
2602
2603The last vestiges of support for this platform have been excised from the
2604Perl distribution. It was officially discontinued in an earlier version.
2605
2606=back
2607
2608=head2 Platform-Specific Notes
2609
d430b8e7
FC
2610=head3 AIX
2611
2612=over
2613
2614=item *
2615
2616F<README.aix> has been updated with information about the XL C/C++ V11 compiler
2617suite (5.12.2).
2618
2619=back
2620
2621=head3 ARM
2622
2623=over
2624
2625=item *
2626
2627The C<d_u32align> configuration probe on ARM has been fixed (5.12.2).
2628
2629=back
2630
554003a2 2631=head3 Cygwin
5076a392
FC
2632
2633=over 4
2634
2635=item *
2636
554003a2 2637MakeMaker has been updated to build man pages on cygwin.
5076a392
FC
2638
2639=item *
2640
554003a2
FC
2641Improved rebase behaviour
2642
2643If a dll is updated on cygwin the old imagebase address is reused.
2644This solves most rebase errors, especially when updating on core dll's.
2645See L<http://www.tishler.net/jason/software/rebase/rebase-2.4.2.README> for more information.
5076a392
FC
2646
2647=item *
2648
554003a2 2649Support for the standard cygwin dll prefix, which is e.g. needed for FFI's
5076a392
FC
2650
2651=item *
2652
554003a2 2653Updated build hints file
5076a392
FC
2654
2655=back
2656
cdc10f43
FC
2657=head3 FreeBSD 7
2658
2659=over
2660
2661=item *
2662
2663FreeBSD 7 no longer contains F</usr/bin/objformat>. At build time,
2664Perl now skips the F<objformat> check for versions 7 and higher and
2665assumes ELF (5.12.1).
2666
2667=back
2668
2669=head3 HP-UX
2670
2671=over
2672
2673=item *
2674
2675Perl now allows -Duse64bitint without promoting to use64bitall on HP-UX
2676(5.12.1).
2677
2678=back
2679
554003a2 2680=head3 IRIX
5076a392
FC
2681
2682Conversion of strings to floating-point numbers is now more accurate on
2683IRIX systems [perl #32380].
2684
554003a2 2685=head3 Mac OS X
5076a392
FC
2686
2687Early versions of Mac OS X (Darwin) had buggy implementations of the
2688C<setregid>, C<setreuid>, C<setrgid> and C<setruid> functions, so perl
2689would pretend they did not exist.
2690
2691These functions are now recognised on Mac OS 10.5 (Leopard; Darwin 9) and
2692higher, as they have been fixed [perl #72990].
2693
554003a2 2694=head3 MirBSD
5076a392 2695
554003a2
FC
2696Previously if you built perl with a shared libperl.so on MirBSD (the
2697default config), it would work up to the installation; however, once
2698installed, it would be unable to find libperl. So path handling is now
2699treated as in the other BSD dialects.
5076a392 2700
554003a2 2701=head3 NetBSD
5076a392 2702
554003a2
FC
2703The NetBSD hints file has been changed to make the system's malloc the
2704default.
5076a392 2705
554003a2 2706=head3 Recent OpenBSDs now use perl's malloc
5076a392 2707
554003a2
FC
2708OpenBSD E<gt> 3.7 has a new malloc implementation which is mmap-based
2709and as such can release memory back to the OS; however, perl's use of
2710this malloc causes a substantial slowdown so we now default to using
2711perl's malloc instead [perl #75742].
5076a392 2712
554003a2 2713=head3 OpenVOS
5076a392 2714
554003a2 2715perl now builds again with OpenVOS (formerly known as Stratus VOS)
5a553547 2716[perl #78132] (5.12.3).
5076a392 2717
554003a2 2718=head3 Solaris
5076a392 2719
554003a2 2720DTrace is now supported on Solaris. There used to be build failures, but
5a553547 2721these have been fixed [perl #73630] (5.12.3).
5076a392 2722
554003a2 2723=head3 VMS
5076a392
FC
2724
2725=over
2726
2727=item *
2728
cdc10f43
FC
2729It's now possible to build extensions on older (pre 7.3-2) VMS systems.
2730
2731DCL symbol length was limited to 1K up until about seven years or
2732so ago, but there was no particularly deep reason to prevent those
2733older systems from configuring and building Perl (5.12.1).
2734
2735=item *
2736
2737We fixed the previously-broken C<-Uuseperlio> build on VMS.
2738
2739We were checking a variable that doesn't exist in the non-default
2740case of disabling perlio. Now we only look at it when it exists (5.12.1).
2741
2742=item *
2743
2744We fixed the -Uuseperlio command-line option in configure.com.
2745
2746Formerly it only worked if you went through all the questions
2747interactively and explicitly answered no (5.12.1).
2748
2749=item *
2750
554003a2 2751C<PerlIOUnix_open> now honours the default permissions on VMS.
5076a392 2752
554003a2
FC
2753When C<perlio> became the default and C<unixio> became the default bottom layer,
2754the most common path for creating files from Perl became C<PerlIOUnix_open>,
2755which has always explicitly used C<0666> as the permission mask.
5076a392 2756
554003a2
FC
2757To avoid this, C<0777> is now passed as the permissions to C<open()>. In the
2758VMS CRTL, C<0777> has a special meaning over and above intersecting with the
2759current umask; specifically, it allows Unix syscalls to preserve native default
5a553547
FC
2760permissions (5.12.3).
2761
2762=item *
2763
2764Spurious record boundaries are no longer
2765introduced by the PerlIO layer during output (5.12.3).
5076a392
FC
2766
2767=item *
2768
554003a2
FC
2769The shortening of symbols longer than 31 characters in the C sources is
2770now done by the compiler rather than by xsubpp (which could only do so
2771for generated symbols in XS code).
5076a392
FC
2772
2773=item *
2774
554003a2
FC
2775Record-oriented files (record format variable or variable with fixed control)
2776opened for write by the perlio layer will now be line-buffered to prevent the
2777introduction of spurious line breaks whenever the perlio buffer fills up.
5076a392 2778
d430b8e7
FC
2779=item *
2780
2781F<git_version.h> is now installed on VMS. This was an oversight in v5.12.0 which
2782caused some extensions to fail to build (5.12.2).
2783
2784=item *
2785
2786Several memory leaks in L<stat()|perlfunc/"stat FILEHANDLE"> have been fixed (5.12.2).
2787
2788=item *
2789
2790A memory leak in C<Perl_rename()> due to a double allocation has been
2791fixed (5.12.2).
2792
2793=item *
2794
2795A memory leak in C<vms_fid_to_name()> (used by C<realpath()> and
2796C<realname()>) has been fixed (5.12.2).
2797
5076a392
FC
2798=back
2799
554003a2 2800=head3 Windows
5076a392 2801
5a1f7719
FC
2802See also L</"fork() emulation will not wait for signalled children"> and
2803L</"Perl source code is read in text mode on Windows">, above.
2804
5076a392
FC
2805=over 4
2806
2807=item *
2808
554003a2 2809Fixed build process for SDK2003SP1 compilers.
5076a392 2810
554003a2 2811=item *
5076a392 2812
01b1a9e4
FC
2813Compilation with Visual Studio 2010 is now supported.
2814
2815=item *
2816
554003a2
FC
2817When using old 32-bit compilers, the define C<_USE_32BIT_TIME_T> will now
2818be set in C<$Config{ccflags}>. This improves portability when compiling
2819XS extensions using new compilers, but for a perl compiled with old 32-bit
2820compilers.
5076a392
FC
2821
2822=item *
2823
554003a2
FC
2824C<$Config{gccversion}> is now set correctly when perl is built using the
2825mingw64 compiler from L<http://mingw64.org> [perl #73754].
5076a392 2826
554003a2
FC
2827=item *
2828
d430b8e7
FC
2829When building Perl with the mingw64 x64 cross-compiler C<incpath>,
2830C<libpth>, C<ldflags>, C<lddlflags> and C<ldflags_nolargefiles> values
2831in F<Config.pm> and F<Config_heavy.pl> were not previously being set
2832correctly because, with that compiler, the include and lib directories
2833are not immediately below C<$(CCHOME)> (5.12.2).
2834
2835=item *
2836
554003a2
FC
2837The build process proceeds more smoothly with mingw and dmake when
2838F<C:\MSYS\bin> is in the PATH, due to a C<Cwd> fix.
5076a392
FC
2839
2840=item *
2841
554003a2
FC
2842Support for building with Visual C++ 2010 is now underway, but is not yet
2843complete. See F<README.win32> or L<perlwin32> for more details.
5076a392 2844
554003a2
FC
2845=item *
2846
2847The option to use an externally-supplied C<crypt()>, or to build with no
2848C<crypt()> at all, has been removed. Perl supplies its own C<crypt()>
2849implementation for Windows, and the political situation that required
2850this part of the distribution to sometimes be omitted is long gone.
5076a392
FC
2851
2852=back
2853
2854=head1 Internal Changes
2855
1e463951 2856=head2 New APIs
5076a392 2857
1e463951 2858=head3 CLONE_PARAMS structure added to ease correct thread creation
5076a392 2859
1e463951
FC
2860Modules that create threads should now create C<CLONE_PARAMS> structures
2861by calling the new function C<Perl_clone_params_new()>, and free them with
2862C<Perl_clone_params_del()>. This will ensure compatibility with any future
2863changes to the internals of the C<CLONE_PARAMS> structure layout, and that
2864it is correctly allocated and initialised.
5076a392 2865
1e463951 2866=head3 New parsing functions
5076a392 2867
1e463951
FC
2868Several functions have been added for parsing statements or multiple
2869statements:
5076a392 2870
1e463951 2871=over
5076a392
FC
2872
2873=item *
2874
1e463951 2875C<parse_fullstmt> parses a complete Perl statement.
5076a392
FC
2876
2877=item *
2878
1e463951
FC
2879C<parse_stmtseq> parses a sequence of statements, up
2880to closing brace or EOF.
5076a392
FC
2881
2882=item *
2883
1e463951 2884C<parse_block> parses a block [perl #78222].
5076a392
FC
2885
2886=item *
2887
1e463951
FC
2888C<parse_barestmt> parses a statement
2889without a label.
5076a392
FC
2890
2891=item *
2892
1e463951 2893C<parse_label> parses a statement label, separate from statements.
5076a392 2894
1e463951 2895=back
5076a392 2896
1e463951
FC
2897The
2898L<C<parse_fullexpr()>|perlapi/parse_fullexpr>,
2899L<C<parse_listexpr()>|perlapi/parse_listexpr>,
2900L<C<parse_termexpr()>|perlapi/parse_termexpr>, and
2901L<C<parse_arithexpr()>|perlapi/parse_arithexpr>
2902functions have been added to the API. They perform
2903recursive-descent parsing of expressions at various precedence levels.
2904They are expected to be used by syntax plugins.
5076a392 2905
1e463951 2906See L<perlapi> for details.
5076a392 2907
1e463951 2908=head3 Hints hash API
5076a392 2909
1e463951
FC
2910A new C API for introspecting the hinthash C<%^H> at runtime has been
2911added. See C<cop_hints_2hv>, C<cop_hints_fetchpvn>, C<cop_hints_fetchpvs>,
2912C<cop_hints_fetchsv>, and C<hv_copy_hints_hv> in L<perlapi> for details.
5076a392 2913
1e463951
FC
2914A new, experimental API has been added for accessing the internal
2915structure that Perl uses for C<%^H>. See the functions beginning with
2916C<cophh_> in L<perlapi>.
5076a392 2917
1e463951 2918=head3 C interface to C<caller()>
5076a392 2919
1e463951
FC
2920The C<caller_cx> function has been added as an XSUB-writer's equivalent of
2921C<caller()>. See L<perlapi> for details.
5076a392 2922
1e463951 2923=head3 Custom per-subroutine check hooks
5076a392 2924
1e463951
FC
2925XS code in an extension module can now annotate a subroutine (whether
2926implemented in XS or in Perl) so that nominated XS code will be called
2927at compile time (specifically as part of op checking) to change the op
2928tree of that subroutine. The compile-time check function (supplied by
2929the extension module) can implement argument processing that can't be
2930expressed as a prototype, generate customised compile-time warnings,
2931perform constant folding for a pure function, inline a subroutine
2932consisting of sufficiently simple ops, replace the whole call with a
2933custom op, and so on. This was previously all possible by hooking the
2934C<entersub> op checker, but the new mechanism makes it easy to tie the
2935hook to a specific subroutine. See L<perlapi/cv_set_call_checker>.
5076a392 2936
1e463951
FC
2937To help in writing custom check hooks, several subtasks within standard
2938C<entersub> op checking have been separated out and exposed in the API.
5076a392 2939
1e463951 2940=head3 Improved support for custom OPs
5076a392 2941
1e463951
FC
2942Custom ops can now be registered with the new C<custom_op_register> C
2943function and the C<XOP> structure. This will make it easier to add new
2944properties of custom ops in the future. Two new properties have been added
2945already, C<xop_class> and C<xop_peep>.
5076a392 2946
1e463951
FC
2947C<xop_class> is one of the OA_*OP constants, and allows L<B> and other
2948introspection mechanisms to work with custom ops
2949that aren't BASEOPs. C<xop_peep> is a pointer to
2950a function that will be called for ops of this
2951type from C<Perl_rpeep>.
5076a392 2952
1e463951
FC
2953See L<perlguts/Custom Operators> and L<perlapi/Custom Operators> for more
2954detail.
5076a392 2955
1e463951
FC
2956The old C<PL_custom_op_names>/C<PL_custom_op_descs> interface is still
2957supported but discouraged.
5076a392 2958
1e463951 2959=head3 Scope hooks
5076a392 2960
1e463951
FC
2961It is now possible for XS code to hook into Perl's lexical scope
2962mechanism at compile time, using the new C<Perl_blockhook_register>
2963function. See L<perlguts/"Compile-time scope hooks">.
5076a392 2964
1e463951 2965=head3 The recursive part of the peephole optimizer is now hookable
5076a392
FC
2966
2967In addition to C<PL_peepp>, for hooking into the toplevel peephole optimizer, a
2968C<PL_rpeepp> is now available to hook into the optimizer recursing into
2969side-chains of the optree.
2970
1e463951 2971=head3 New non-magical variants of existing functions
5076a392 2972
1e463951
FC
2973The following functions/macros have been added to the API. The C<*_nomg>
2974macros are equivalent to their non-_nomg variants, except that they ignore
2975get-magic. Those ending in C<_flags> allow one to specify whether
2976get-magic is processed.
5076a392 2977
1e463951
FC
2978 sv_2bool_flags
2979 SvTRUE_nomg
2980 sv_2nv_flags
2981 SvNV_nomg
2982 sv_cmp_flags
2983 sv_cmp_locale_flags
2984 sv_eq_flags
2985 sv_collxfrm_flags
5076a392 2986
1e463951 2987In some of these cases, the non-_flags functions have
5076a392
FC
2988been replaced with wrappers around the new functions.
2989
1e463951 2990=head3 pv/pvs/sv versions of existing functions
5076a392 2991
1e463951 2992Many functions ending with pvn now have equivalent pv/pvs/sv versions.
5076a392 2993
1e463951 2994=head3 List op-building functions
5076a392 2995
1e463951
FC
2996List op-building functions have been added to the
2997API. See L<op_append_elem|perlapi/op_append_elem>,
2998L<op_append_list|perlapi/op_append_list>, and
2999L<op_prepend_elem|perlapi/op_prepend_elem> in L<perlapi>.
5076a392 3000
1e463951 3001=head3 C<LINKLIST>
5076a392 3002
1e463951
FC
3003The L<LINKLIST|perlapi/LINKLIST> macro, part of op building that
3004constructs the execution-order op chain, has been added to the API.
5076a392 3005
1e463951 3006=head3 Localisation functions
5076a392 3007
1e463951
FC
3008The C<save_freeop>, C<save_op>, C<save_pushi32ptr> and C<save_pushptrptr>
3009functions have been added to the API.
5076a392 3010
1e463951 3011=head3 Stash names
5076a392 3012
1e463951
FC
3013A stash can now have a list of effective names in addition to its usual
3014name. The first effective name can be accessed via the C<HvENAME> macro,
3015which is now the recommended name to use in MRO linearisations (C<HvNAME>
3016being a fallback if there is no C<HvENAME>).
5076a392 3017
1e463951
FC
3018These names are added and deleted via C<hv_ename_add> and
3019C<hv_ename_delete>. These two functions are I<not> part of the API.
5076a392 3020
1e463951 3021=head3 New functions for finding and removing magic
5076a392 3022
1e463951
FC
3023The L<C<mg_findext()>|perlapi/mg_findext> and
3024L<C<sv_unmagicext()>|perlapi/sv_unmagicext>
3025functions have been added to the API.
3026They allow extension authors to find and remove magic attached to
3027scalars based on both the magic type and the magic virtual table, similar to how
3028C<sv_magicext()> attaches magic of a certain type and with a given virtual table
3029to a scalar. This eliminates the need for extensions to walk the list of
3030C<MAGIC> pointers of an C<SV> to find the magic that belongs to them.
5076a392 3031
1e463951 3032=head3 C<find_rundefsv>
5076a392 3033
1e463951
FC
3034This function returns the SV representing C<$_>, whether it's lexical
3035or dynamic.
5076a392 3036
1e463951 3037=head3 C<Perl_croak_no_modify>
5076a392 3038
1e463951
FC
3039C<Perl_croak_no_modify()> is short-hand for
3040C<Perl_croak("%s", PL_no_modify)>.
5076a392 3041
1e463951 3042=head3 C<PERL_STATIC_INLINE> define
5076a392 3043
1e463951
FC
3044The C<PERL_STATIC_INLINE> define has been added to provide the best-guess
3045incantation to use for static inline functions, if the C compiler supports
3046C99-style static inline. If it doesn't, it'll give a plain C<static>.
5076a392 3047
1e463951
FC
3048C<HAS_STATIC_INLINE> can be used to check if the compiler actually supports
3049inline functions.
5076a392 3050
1e463951 3051=head3 New C<pv_escape> option for hexadecimal escapes
5076a392 3052
1e463951
FC
3053A new option, C<PERL_PV_ESCAPE_NONASCII>, has been added to C<pv_escape> to
3054dump all characters above ASCII in hexadecimal. Before, one could get all
3055characters as hexadecimal or the Latin1 non-ASCII as octal.
5076a392 3056
1e463951 3057=head3 C<lex_start>
5076a392 3058
1e463951 3059C<lex_start> has been added to the API, but is considered experimental.
5076a392 3060
1e463951 3061=head3 C<op_scope()> and C<op_lvalue()>
5076a392 3062
1e463951
FC
3063The C<op_scope()> and C<op_lvalue()> functions have been added to the API,
3064but are considered experimental.
5076a392 3065
1e463951 3066=head2 C API Changes
5076a392 3067
1e463951 3068=head3 C<PERL_POLLUTE> has been removed
5076a392 3069
1e463951
FC
3070The option to define C<PERL_POLLUTE> to expose older 5.005 symbols for
3071backwards compatibility has been removed. It's use was always discouraged,
3072and MakeMaker contains a more specific escape hatch:
5076a392 3073
1e463951 3074 perl Makefile.PL POLLUTE=1
5076a392 3075
1e463951
FC
3076This can be used for modules that have not been upgraded to 5.6 naming
3077conventions (and really should be completely obsolete by now).
5076a392 3078
1e463951 3079=head3 Check API compatibility when loading XS modules
5076a392 3080
1e463951
FC
3081When perl's API changes in incompatible ways (which usually happens between
3082major releases), XS modules compiled for previous versions of perl will not
3083work anymore. They will need to be recompiled against the new perl.
5076a392 3084
1e463951
FC
3085In order to ensure that modules are recompiled, and to prevent users from
3086accidentally loading modules compiled for old perls into newer ones, the
3087C<XS_APIVERSION_BOOTCHECK> macro has been added. That macro, which is
3088called when loading every newly compiled extension, compares the API
3089version of the running perl with the version a module has been compiled for
3090and raises an exception if they don't match.
5076a392 3091
1e463951 3092=head3 Perl_fetch_cop_label
5076a392 3093
1e463951
FC
3094The first argument of the C API function C<Perl_fetch_cop_label> has changed
3095from C<struct refcounted he *> to C<COP *>, to insulate the user from
3096implementation details.
5076a392 3097
1e463951
FC
3098This API function was marked as "may change", and likely isn't in use outside
3099the core. (Neither an unpacked CPAN, nor Google's codesearch, finds any other
3100references to it.)
5076a392 3101
1e463951 3102=head3 GvCV() and GvGP() are no longer lvalues
5076a392 3103
1e463951
FC
3104The new GvCV_set() and GvGP_set() macros are now provided to replace
3105assignment to those two macros.
5076a392 3106
1e463951
FC
3107This allows a future commit to eliminate some backref magic between GV
3108and CVs, which will require complete control over assignment to the
3109gp_cv slot.
5076a392 3110
1e463951 3111=head3 CvGV() is no longer an lvalue
5076a392 3112
1e463951
FC
3113Under some circumstances, the C<CvGV()> field of a CV is now
3114reference-counted. To ensure consistent behaviour, direct assignment to
3115it, for example C<CvGV(cv) = gv> is now a compile-time error. A new macro,
3116C<CvGV_set(cv,gv)> has been introduced to perform this operation
3117safely. Note that modification of this field is not part of the public
3118API, regardless of this new macro (and despite its being listed in this section).
5076a392 3119
1e463951 3120=head3 CvSTASH() is no longer an lvalue
5076a392 3121
1e463951
FC
3122The C<CvSTASH()> macro can now only be used as an rvalue. C<CvSTASH_set()>
3123has been added to replace assignment to C<CvSTASH()>. This is to ensure
3124that backreferences are handled properly. These macros are not part of the
3125API.
5076a392 3126
1e463951 3127=head3 Calling conventions for C<newFOROP> and C<newWHILEOP>
5076a392 3128
1e463951
FC
3129The way the parser handles labels has been cleaned up and refactored. As a
3130result, the C<newFOROP()> constructor function no longer takes a parameter
3131stating what label is to go in the state op.
5076a392 3132
1e463951
FC
3133The C<newWHILEOP()> and C<newFOROP()> functions no longer accept a line
3134number as a parameter.
5076a392 3135
1e463951 3136=head3 Flags passed to C<uvuni_to_utf8_flags> and C<utf8n_to_uvuni>
5076a392 3137
1e463951
FC
3138Some of the flags parameters to uvuni_to_utf8_flags() and
3139utf8n_to_uvuni() have changed. This is a result of Perl's now allowing
5076a392
FC
3140internal storage and manipulation of code points that are problematic
3141in some situations. Hence, the default actions for these functions has
3142been complemented to allow these code points. The new flags are
3143documented in L<perlapi>. Code that requires the problematic code
483b16f3 3144points to be rejected needs to change to use the new flags. Some flag
5076a392
FC
3145names are retained for backward source compatibility, though they do
3146nothing, as they are now the default. However the flags
3147C<UNICODE_ALLOW_FDD0>, C<UNICODE_ALLOW_FFFF>, C<UNICODE_ILLEGAL>, and
3148C<UNICODE_IS_ILLEGAL> have been removed, as they stem from a
3149fundamentally broken model of how the Unicode non-character code points
3150should be handled, which is now described in
3151L<perlunicode/Non-character code points>. See also L</Selected Bug Fixes>.
3152
1e463951 3153XXX Which bugs in particular? Selected Bug Fixes is too long for this link
483b16f3
KW
3154to be meaningful right now
3155I don't see the bugs in that section currently -- khw
5076a392 3156
1e463951 3157=head2 Deprecated C APIs
5076a392 3158
1e463951 3159=over
5076a392 3160
1e463951 3161=item C<Perl_ptr_table_clear>
5076a392 3162
1e463951
FC
3163C<Perl_ptr_table_clear> is no longer part of Perl's public API. Calling it
3164now generates a deprecation warning, and it will be removed in a future
3165release.
5076a392 3166
1e463951 3167=item C<sv_compile_2op>
5076a392 3168
1e463951
FC
3169The C<sv_compile_2op()> API function is now deprecated. Searches suggest
3170that nothing on CPAN is using it, so this should have zero impact.
5076a392 3171
1e463951
FC
3172It attempted to provide an API to compile code down to an optree, but failed
3173to bind correctly to lexicals in the enclosing scope. It's not possible to
3174fix this problem within the constraints of its parameters and return value.
5076a392 3175
1e463951 3176=item C<find_rundefsvoffset>
5076a392 3177
1e463951
FC
3178The C<find_rundefsvoffset> function has been deprecated. It appeared that
3179its design was insufficient for reliably getting the lexical C<$_> at
3180run-time.
5076a392 3181
1e463951
FC
3182Use the new C<find_rundefsv> function or the C<UNDERBAR> macro
3183instead. They directly return the right SV representing C<$_>, whether it's
3184lexical or dynamic.
5076a392 3185
1e463951 3186=item C<CALL_FPTR> and C<CPERLscope>
5076a392 3187
1e463951
FC
3188Those are left from an old implementation of C<MULTIPLICITY> using C++ objects,
3189which was removed in Perl 5.8. Nowadays these macros do exactly nothing, so
3190they shouldn't be used anymore.
5076a392 3191
1e463951
FC
3192For compatibility, they are still defined for external C<XS> code. Only
3193extensions defining C<PERL_CORE> must be updated now.
5076a392 3194
1e463951 3195=back
5076a392 3196
1e463951 3197=head2 Other Internal Changes
5076a392 3198
1e463951 3199=head3 Stack unwinding
5076a392 3200
1e463951
FC
3201The protocol for unwinding the C stack at the last stage of a C<die>
3202has changed how it identifies the target stack frame. This now uses
3203a separate variable C<PL_restartjmpenv>, where previously it relied on
3204the C<blk_eval.cur_top_env> pointer in the C<eval> context frame that
3205has nominally just been discarded. This change means that code running
3206during various stages of Perl-level unwinding no longer needs to take
3207care to avoid destroying the ghost frame.
5076a392 3208
1e463951 3209=head3 Scope stack entries
5076a392 3210
1e463951
FC
3211The format of entries on the scope stack has been changed, resulting in a
3212reduction of memory usage of about 10%. In particular, the memory used by
3213the scope stack to record each active lexical variable has been halved.
5076a392 3214
1e463951 3215=head3 Memory allocation for pointer tables
5076a392 3216
1e463951
FC
3217Memory allocation for pointer tables has been changed. Previously
3218C<Perl_ptr_table_store> allocated memory from the same arena system as
3219C<SV> bodies and C<HE>s, with freed memory remaining bound to those arenas
3220until interpreter exit. Now it allocates memory from arenas private to the
3221specific pointer table, and that memory is returned to the system when
3222C<Perl_ptr_table_free> is called. Additionally, allocation and release are
3223both less CPU intensive.
5076a392 3224
1e463951 3225=head3 C<UNDERBAR>
5076a392 3226
1e463951
FC
3227The C<UNDERBAR> macro now calls C<find_rundefsv>. C<dUNDERBAR> is now a
3228noop but should still be used to ensure past and future compatibility.
5076a392 3229
1e463951 3230=head3 String comparison routines renamed
5076a392 3231
1e463951
FC
3232The ibcmp_* functions have been renamed and are now called foldEQ,
3233foldEQ_locale and foldEQ_utf8. The old names are still available as
3234macros.
3235
3236=head3 C<chop> and C<chomp> implementations merged
3237
3238The opcode bodies for C<chop> and C<chomp> and for C<schop> and C<schomp>
3239have been merged. The implementation functions C<Perl_do_chop()> and
3240C<Perl_do_chomp()>, never part of the public API, have been merged and
3241moved to a static function in F<pp.c>. This shrinks the perl binary
3242slightly, and should not affect any code outside the core (unless it is
3243relying on the order of side effects when C<chomp> is passed a I<list> of
3244values).
5076a392
FC
3245
3246=head1 Selected Bug Fixes
3247
e8e35311
FC
3248=head2 I/O
3249
5076a392
FC
3250=over 4
3251
3252=item *
3253
e8e35311 3254Perl no longer produces this warning:
a593b319
FC
3255
3256 $ perl -we 'open my $f, ">", \my $x; binmode $f, "scalar"'
3257 Use of uninitialized value in binmode at -e line 1.
3258
3259=item *
3260
e8e35311
FC
3261Opening a glob reference via C<< open $fh, "E<gt>", \*glob >> will no longer
3262cause the glob to be corrupted when the filehandle is printed to. This would
3263cause perl to crash whenever the glob's contents were accessed
3264[perl #77492].
4ed2cea4
FC
3265
3266=item *
3267
e8e35311
FC
3268PerlIO no longer crashes when called recursively, e.g., from a signal
3269handler. Now it just leaks memory [perl #75556].
4ed2cea4
FC
3270
3271=item *
3272
e8e35311
FC
3273Most I/O functions were not warning for unopened handles unless the
3274'closed' and 'unopened' warnings categories were both enabled. Now only
3275C<use warnings 'unopened'> is necessary to trigger these warnings (as was
438c239f 3276always meant to be the case).
4ed2cea4
FC
3277
3278=item *
3279
438c239f 3280There have been several fixes to PerlIO layers:
e8e35311 3281
438c239f
FC
3282When C<binmode FH, ":crlf"> pushes the C<:crlf> layer on top of the stack,
3283it no longer enables crlf layers lower in the stack, to avoid unexpected
3284results [perl #38456].
4ed2cea4 3285
438c239f
FC
3286Opening a file in C<:raw> mode now does what it advertises to do (first
3287open the file, then binmode it), instead of simply leaving off the top
3288layer [perl #80764].
5076a392 3289
438c239f
FC
3290The three layers C<:pop>, C<:utf8> and C<:bytes> didn't allow stacking when
3291opening a file. For example
e8e35311 3292this:
5076a392 3293
e8e35311 3294 open FH, '>:pop:perlio', 'some.file' or die $!;
5076a392 3295
438c239f
FC
3296Would throw an error: "Invalid argument". This has been fixed in this
3297release [perl #82484].
5076a392 3298
e8e35311
FC
3299=back
3300
3301=head2 Regular Expression Bug Fixes
3302
3303=over
5076a392
FC
3304
3305=item *
3306
e8e35311
FC
3307The regular expression engine no longer loops when matching
3308C<"\N{LATIN SMALL LIGATURE FF}" =~ /f+/i> and similar expressions
cdc10f43 3309[perl #72998] (5.12.1).
5076a392
FC
3310
3311=item *
3312
e8e35311
FC
3313The trie runtime code should no longer allocate massive amounts of memory,
3314fixing #74484.
5076a392
FC
3315
3316=item *
3317
438c239f
FC
3318Syntax errors in C<< (?{...}) >> blocks no longer cause panic messages
3319[perl #2353].
5076a392
FC
3320
3321=item *
3322
438c239f
FC
3323A pattern like C<(?:(o){2})?> no longer causes a "panic" error
3324[perl #39233].
5076a392
FC
3325
3326=item *
3327
438c239f 3328A fatal error in regular expressions containing C<(.*?)> when processing
d430b8e7 3329UTF-8 data has been fixed [perl #75680] (5.12.2).
5076a392
FC
3330
3331=item *
3332
e8e35311 3333An erroneous regular expression engine optimisation that caused regex verbs like
438c239f 3334C<*COMMIT> sometimes to be ignored has been removed.
5076a392
FC
3335
3336=item *
3337
e8e35311
FC
3338The regular expression bracketed character class C<[\8\9]> was effectively the
3339same as C<[89\000]>, incorrectly matching a NULL character. It also gave
3340incorrect warnings that the C<8> and C<9> were ignored. Now C<[\8\9]> is the
3341same as C<[89]> and gives legitimate warnings that C<\8> and C<\9> are
3342unrecognized escape sequences, passed-through.
5076a392
FC
3343
3344=item *
3345
e8e35311
FC
3346A regular expression match in the right-hand side of a global substitution
3347(C<s///g>) that is in the same scope will no longer cause match variables
3348to have the wrong values on subsequent iterations. This can happen when an
3349array or hash subscript is interpolated in the right-hand side, as in
3350C<s|(.)|@a{ print($1), /./ }|g> [perl #19078].
5076a392
FC
3351
3352=item *
3353
438c239f
FC
3354Several cases in which characters in the Latin-1 non-ASCII range (0x80 to
33550xFF) used not to match themselves or used to match both a character class
3356and its complement have been fixed. For instance, U+00E2 could match both
3357C<\w> and C<\W> [perl #78464] [perl #18281] [perl #60156].
5076a392
FC
3358
3359=item *
3360
e8e35311
FC
3361Matching a Unicode character against an alternation containing characters
3362that happened to match continuation bytes in the former's UTF8
3363representation (C<qq{\x{30ab}} =~ /\xab|\xa9/>) would cause erroneous
3364warnings [perl #70998].
5076a392
FC
3365
3366=item *
3367
e8e35311
FC
3368The trie optimisation was not taking empty groups into account, preventing
3369'foo' from matching C</\A(?:(?:)foo|bar|zot)\z/> [perl #78356].
5076a392
FC
3370
3371=item *
3372
e8e35311
FC
3373A pattern containing a C<+> inside a lookahead would sometimes cause an
3374incorrect match failure in a global match (e.g., C</(?=(\S+))/g>)
3375[perl #68564].
5076a392
FC
3376
3377=item *
3378
e8e35311
FC
3379A regular expression optimisation would sometimes cause a match with a
3380C<{n,m}> quantifier to fail when it should match [perl #79152].
5076a392
FC
3381
3382=item *
3383
e8e35311 3384Case insensitive matching in regular expressions compiled under C<use
438c239f
FC
3385locale> now works much more sanely when the pattern or
3386target string is encoded internally in
3387UTF8. Previously, under these conditions the localeness
e8e35311
FC
3388was completely lost. Now, code points above 255 are treated as Unicode,
3389but code points between 0 and 255 are treated using the current locale
438c239f
FC
3390rules, regardless of whether the pattern or the string is encoded in UTF8.
3391The few case-insensitive matches that cross the 255/256 boundary are not
e8e35311
FC
3392allowed. For example, 0xFF does not caselessly match the character at
33930x178, LATIN CAPITAL LETTER Y WITH DIAERESIS, because 0xFF may not be
3394LATIN SMALL LETTER Y in the current locale, and Perl has no way of
3395knowing if that character even exists in the locale, much less what code
3396point it is.
5076a392
FC
3397
3398=item *
3399
e8e35311
FC
3400The C<(?|...)> regular expression construct no longer crashes if the final
3401branch has more sets of capturing parentheses than any other branch. This
3402was fixed in Perl 5.10.1 for the case of a single branch, but that fix did
3403not take multiple branches into account [perl #84746].
5076a392
FC
3404
3405=item *
3406
e8e35311
FC
3407A bug has been fixed in the implementation of C<{...}> quantifiers in
3408regular expressions that prevented the code block in
3409C</((\w+)(?{ print $2 })){2}/> from seeing the C<$2> sometimes
3410[perl #84294].
5076a392 3411
e8e35311 3412=back
5076a392 3413
e8e35311
FC
3414=head2 Syntax/Parsing Bugs
3415
3416=over
5076a392
FC
3417
3418=item *
3419
e8e35311 3420C<when(scalar){...}> no longer crashes, but produces a syntax error
cdc10f43 3421[perl #74114] (5.12.1).
5076a392
FC
3422
3423=item *
3424
e8e35311
FC
3425A label right before a string eval (C<foo: eval $string>) no longer causes
3426the label to be associated also with the first statement inside the eval
3427[perl #74290] (5.12.1).
5076a392
FC
3428
3429=item *
3430
b2c076b5 3431The C<no 5.13.2;> form of C<no> no longer tries to turn on features or
d430b8e7 3432pragmata (i.e., strict) [perl #70075] (5.12.2).
5076a392
FC
3433
3434=item *
3435
b2c076b5
FC
3436C<BEGIN {require 5.12.0}> now behaves as documented, rather than behaving
3437identically to C<use 5.12.0;>. Previously, C<require> in a C<BEGIN> block
3438was erroneously executing the C<use feature ':5.12.0'> and
3439C<use strict;> behaviour, which only C<use> was documented to
3440provide [perl #69050].
5076a392
FC
3441
3442=item *
3443
5076a392
FC
3444A regression introduced in Perl 5.12.0, making
3445C<< my $x = 3; $x = length(undef) >> result in C<$x> set to C<3> has been
d430b8e7 3446fixed. C<$x> will now be C<undef> [perl #85508] (5.12.2).
b2c076b5
FC
3447
3448=item *
3449
3450When strict 'refs' mode is off, C<%{...}> in rvalue context returns
3451C<undef> if its argument is undefined. An optimisation introduced in perl
34525.12.0 to make C<keys %{...}> faster when used as a boolean did not take
3453this into account, causing C<keys %{+undef}> (and C<keys %$foo> when
3454C<$foo> is undefined) to be an error, which it should only be in strict
3455mode [perl #81750].
5076a392
FC
3456
3457=item *
3458
e8e35311 3459Constant-folding used to cause
5076a392 3460
e8e35311 3461 $text =~ ( 1 ? /phoo/ : /bear/)
5076a392 3462
e8e35311
FC
3463to turn into
3464
3465 $text =~ /phoo/
3466
3467at compile time. Now it correctly matches against C<$_> [perl #20444].
5076a392
FC
3468
3469=item *
3470
e8e35311
FC
3471Parsing Perl code (either with string C<eval> or by loading modules) from
3472within a C<UNITCHECK> block no longer causes the interpreter to crash
3473[perl #70614].
5076a392
FC
3474
3475=item *
3476
b2c076b5
FC
3477String evals no longer fail after 2 billion scopes have been
3478compiled [perl #83364].
3479
3480=item *
3481
e8e35311
FC
3482The parser no longer hangs when encountering certain Unicode characters,
3483such as U+387 [perl #74022].
5076a392
FC
3484
3485=item *
3486
b2c076b5
FC
3487Several contexts no longer allow a Unicode character to begin a word
3488that should never begin words, for an example an accent that must follow
3489another character previously could precede all other characters.
5076a392
FC
3490
3491=item *
3492
e8e35311
FC
3493Defining a constant with the same name as one of perl's special blocks
3494(e.g., INIT) stopped working in 5.12.0, but has now been fixed
3495[perl #78634].
5076a392
FC
3496
3497=item *
3498
e8e35311
FC
3499A reference to a literal value used as a hash key (C<$hash{\"foo"}>) used
3500to be stringified, even if the hash was tied [perl #79178].
5076a392
FC
3501
3502=item *
3503
e8e35311
FC
3504A closure containing an C<if> statement followed by a constant or variable
3505is no longer treated as a constant [perl #63540].
5076a392
FC
3506
3507=item *
3508
e8e35311
FC
3509C<state> can now be used with attributes. It used to mean the same thing as
3510C<my> if attributes were present [perl #68658].
5076a392
FC
3511
3512=item *
3513
e8e35311
FC
3514Expressions like C<< @$a > 3 >> no longer cause C<$a> to be mentioned in
3515the "Use of uninitialized value in numeric gt" warning when C<$a> is
3516undefined (since it is not part of the C<E<gt>> expression, but the operand
3517of the C<@>) [perl #72090].
5076a392
FC
3518
3519=item *
3520
e8e35311
FC
3521Accessing an element of a package array with a hard-coded number (as
3522opposed to an arbitrary expression) would crash if the array did not exist.
3523Usually the array would be autovivified during compilation, but typeglob
3524manipulation could remove it, as in these two cases which used to crash:
5076a392 3525
e8e35311
FC
3526 *d = *a; print $d[0];
3527 undef *d; print $d[0];
5076a392 3528
2c389f6c
FC
3529=item *
3530
3531The C<-C> command line option, when used on the shebang line, can now be
3532followed by other options [perl #72434].
3533
3534=item *
3535
3536The C<B> module was returning C<B::OP>s instead of C<B::LOGOP>s for C<entertry> [perl #80622].
3537This was due to a bug in the perl core, not in C<B> itself.
3538
e8e35311 3539=back
5076a392 3540