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1=encoding utf8
2
3=head1 NAME
4
5076a392 5perldelta - what is new for perl v5.14.0
c71a852f 6
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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
43new name for U+0007 in Perl will be C<ALERT>, which corresponds nicely
44with the existing shorthand sequence for it, C<"\a">. C<\N{BEL}> will
45mean U+0007, with no warning given. The character at U+1F514 will not
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
375On Linux the legacy process name will be set with L<prctl(2)>, in
376addition to altering the POSIX name via C<argv[0]> as perl has done
377since version 4.000. Now system utilities that read the legacy process
378name such as ps, top and killall will recognize the name you set when
379assigning to C<$0>. The string you supply will be cut off at 16 bytes,
380this is a limitation imposed by Linux.
381
382=head3 C<srand()> now returns the seed
383
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384This allows programs that need to have repeatable results not to have to come
385up with their own seed-generating mechanism. Instead, they can use C<srand()>
386and stash the return value for future use. Typical is a test program which
1f539a1a 387has too many combinations to test comprehensively in the time available to it
e1b1739f 388each run. It can test a random subset each time and, should there be a failure,
1f539a1a 389log the seed used for that run so that it can later be used to reproduce the
e1b1739f 390same results.
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391
392=head3 printf-like functions understand post-1980 size modifiers
393
394Perl's printf and sprintf operators, and Perl's internal printf replacement
395function, now understand the C90 size modifiers "hh" (C<char>), "z"
396(C<size_t>), and "t" (C<ptrdiff_t>). Also, when compiled with a C99
397compiler, Perl now understands the size modifier "j" (C<intmax_t>).
398
399So, for example, on any modern machine, C<sprintf('%hhd', 257)> returns '1'.
400
401=head3 New global variable C<${^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
494convention has been enforced.
5076a392 495
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496Also, Perl no longer allows a tainted regular expression to invoke a
497user-defined. 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}> -
514C<\x{1FF}>, with no deprecation warning. Use of these values in the
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
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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
61752d82
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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
5076a392
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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
61752d82
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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
61752d82
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588 use re 'eval';
589 $foo =~ $bar; # when $bar contains (?{...})
590 $foo =~ /$bar(?{ $finished = 1 })/;
591
592This was a bug, which has now been fixed. But it has the potential to break
593any code that was relying on it.
5076a392 594
61752d82 595=head2 Stashes and Package Variables
5076a392 596
61752d82 597=head3 Localised tied hashes and arrays are no longed tied
5076a392 598
61752d82 599In the following:
5076a392 600
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601 tie @a, ...;
602 {
603 local @a;
604 # here, @a is a now a new, untied array
605 }
606 # here, @a refers again to the old, tied array
5076a392 607
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608The new local array used to be made tied too, which was fairly pointless,
609and has now been fixed. This fix could however potentially cause a change
610in behaviour of some code.
5076a392 611
61752d82 612=head3 Stashes are now always defined
5076a392 613
61752d82
FC
614C<defined %Foo::> now always returns true, even when no symbols have yet been
615defined in that package.
5076a392 616
61752d82
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617This is a side effect of removing a special case kludge in the tokeniser,
618added for 5.10.0, to hide side effects of changes to the internal storage of
619hashes that drastically reduce their memory usage overhead.
620
621Calling defined on a stash has been deprecated since 5.6.0, warned on
622lexicals since 5.6.0, and warned for stashes (and other package
623variables) since 5.12.0. C<defined %hash> has always exposed an
624implementation detail - emptying a hash by deleting all entries from it does
625not make C<defined %hash> false, hence C<defined %hash> is not valid code to
626determine whether an arbitrary hash is empty. Instead, use the behaviour
627that an empty C<%hash> always returns false in a scalar context.
628
629=head3 Dereferencing typeglobs
5076a392
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630
631If you assign a typeglob to a scalar variable:
632
633 $glob = *foo;
634
635the glob that is copied to C<$glob> is marked with a special flag
636indicating that the glob is just a copy. This allows subsequent assignments
637to C<$glob> to overwrite the glob. The original glob, however, is
638immutable.
639
640Many Perl operators did not distinguish between these two types of globs.
641This would result in strange behaviour in edge cases: C<untie $scalar>
642would do nothing if the last thing assigned to the scalar was a glob
643(because it treated it as C<untie *$scalar>, which unties a handle).
f318e2e6 644Assignment to a glob slot (e.g., C<*$glob = \@some_array>) would simply
5076a392
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645assign C<\@some_array> to C<$glob>.
646
647To fix this, the C<*{}> operator (including the C<*foo> and C<*$foo> forms)
648has been modified to make a new immutable glob if its operand is a glob
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FC
649copy. This allows operators that make a distinction between globs and
650scalars to be modified to treat only immutable globs as globs. (C<tie>,
651C<tied> and C<untie> have been left as they are for compatibility's sake,
61752d82 652but will warn. See L</Deprecations>.)
5076a392
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653
654This causes an incompatible change in code that assigns a glob to the
655return value of C<*{}> when that operator was passed a glob copy. Take the
656following code, for instance:
657
658 $glob = *foo;
659 *$glob = *bar;
660
661The C<*$glob> on the second line returns a new immutable glob. That new
662glob is made an alias to C<*bar>. Then it is discarded. So the second
663assignment has no effect.
664
5076a392
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665See L<http://rt.perl.org/rt3/Public/Bug/Display.html?id=77810> for even
666more detail.
667
61752d82 668=head3 Clearing stashes
5076a392
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669
670Stash list assignment C<%foo:: = ()> used to make the stash anonymous
671temporarily while it was being emptied. Consequently, any of its
672subroutines referenced elsewhere would become anonymous (showing up as
673"(unknown)" in C<caller>). Now they retain their package names, such that
674C<caller> will return the original sub name if there is still a reference
675to its typeglob, or "foo::__ANON__" otherwise [perl #79208].
676
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677=head3 Magic variables outside the main package
678
679In previous versions of Perl, magic variables like C<$!>, C<%SIG>, etc. would
680'leak' into other packages. So C<%foo::SIG> could be used to access signals,
681C<${"foo::!"}> (with strict mode off) to access C's C<errno>, etc.
682
683This was a bug, or an 'unintentional' feature, which caused various ill effects,
684such as signal handlers being wiped when modules were loaded, etc.
685
686This has been fixed (or the feature has been removed, depending on how you see
687it).
688
689=head2 Changes to Syntax or to Perl Operators
690
691=head3 C<given> return values
692
693C<given> blocks now return the last evaluated
694expression, or an empty list if the block was exited by C<break>. Thus you
695can now write:
696
697 my $type = do {
698 given ($num) {
699 break when undef;
700 'integer' when /^[+-]?[0-9]+$/;
701 'float' when /^[+-]?[0-9]+(?:\.[0-9]+)?$/;
702 'unknown';
703 }
704 };
705
706See L<perlsyn/Return value> for details.
707
708=head3 Change in the parsing of certain prototypes
709
710Functions declared with the following prototypes now behave correctly as unary
711functions:
712
713 *
714 \$ \% \@ \* \&
715 \[...]
716 ;$ ;*
717 ;\$ ;\% etc.
718 ;\[...]
719
720Due to this bug fix [perl #75904], functions
721using the C<(*)>, C<(;$)> and C<(;*)> prototypes
722are parsed with higher precedence than before. So in the following example:
723
724 sub foo($);
725 foo $a < $b;
726
727the second line is now parsed correctly as C<< foo($a) < $b >>, rather than
728C<< foo($a < $b) >>. This happens when one of these operators is used in
729an unparenthesised argument:
730
731 < > <= >= lt gt le ge
732 == != <=> eq ne cmp ~~
733 &
734 | ^
735 &&
736 || //
737 .. ...
738 ?:
739 = += -= *= etc.
740
741=head3 Smart-matching against array slices
742
743Previously, the following code resulted in a successful match:
744
745 my @a = qw(a y0 z);
746 my @b = qw(a x0 z);
747 @a[0 .. $#b] ~~ @b;
748
749This odd behaviour has now been fixed [perl #77468].
750
751=head3 Negation treats strings differently from before
752
753The unary negation operator C<-> now treats strings that look like numbers
754as numbers [perl #57706].
755
756=head3 Negative zero
757
758Negative zero (-0.0), when converted to a string, now becomes "0" on all
759platforms. It used to become "-0" on some, but "0" on others.
760
761If you still need to determine whether a zero is negative, use
762C<sprintf("%g", $zero) =~ /^-/> or the L<Data::Float> module on CPAN.
763
764=head3 C<:=> is now a syntax error
5076a392
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765
766Previously C<my $pi := 4;> was exactly equivalent to C<my $pi : = 4;>,
767with the C<:> being treated as the start of an attribute list, ending before
768the C<=>. The use of C<:=> to mean C<: => was deprecated in 5.12.0, and is now
769a syntax error. This will allow the future use of C<:=> as a new token.
770
771We find no Perl 5 code on CPAN using this construction, outside the core's
772tests for it, so we believe that this change will have very little impact on
773real-world codebases.
774
775If it is absolutely necessary to have empty attribute lists (for example,
776because of a code generator) then avoid the error by adding a space before
777the C<=>.
778
61752d82 779=head2 Threads and Processes
5076a392 780
61752d82 781=head3 Directory handles not copied to threads
5076a392 782
61752d82
FC
783On systems other than Windows that do not have
784a C<fchdir> function, newly-created threads no
785longer inherit directory handles from their parent threads. Such programs
786would usually have crashed anyway [perl #75154].
5076a392 787
61752d82 788=head3 C<close> on shared pipes
5076a392 789
61752d82
FC
790The C<close> function no longer waits for the child process to exit if the
791underlying file descriptor is still in use by another thread, to avoid
792deadlocks. It returns true in such cases.
5076a392 793
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794=head3 fork() emulation will not wait for signalled children
795
796On Windows parent processes would not terminate until all forked
797childred had terminated first. However, C<kill('KILL', ...)> is
798inherently unstable on pseudo-processes, and C<kill('TERM', ...)>
799might not get delivered if the child if blocked in a system call.
800
801To avoid the deadlock and still provide a safe mechanism to terminate
802the hosting process, Perl will now no longer wait for children that
803have been sent a SIGTERM signal. It is up to the parent process to
804waitpid() for these children if child clean-up processing must be
805allowed to finish. However, it is also the responsibility of the
806parent then to avoid the deadlock by making sure the child process
807can't be blocked on I/O either.
808
809See L<perlfork> for more information about the fork() emulation on
810Windows.
811
61752d82 812=head2 Configuration
5076a392 813
61752d82 814=head3 Naming fixes in Policy_sh.SH may invalidate Policy.sh
5076a392 815
61752d82
FC
816Several long-standing typos and naming confusions in Policy_sh.SH have
817been fixed, standardizing on the variable names used in config.sh.
5076a392 818
61752d82
FC
819This will change the behavior of Policy.sh if you happen to have been
820accidentally relying on the Policy.sh incorrect behavior.
f318e2e6 821
5a1f7719
FC
822=head3 Perl source code is read in text mode on Windows
823
824Perl scripts used to be read in binary mode on Windows for the benefit
825of the ByteLoader module (which is no longer part of core Perl). This
826had the side effect of breaking various operations on the DATA filehandle,
827including seek()/tell(), and even simply reading from DATA after file handles
828have been flushed by a call to system(), backticks, fork() etc.
829
830The default build options for Windows have been changed to read Perl source
831code on Windows in text mode now. Hopefully ByteLoader will be updated on
832CPAN to automatically handle this situation [perl #28106].
833
5076a392
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834=head1 Deprecations
835
1e463951
FC
836See also L</Deprecated C APIs>.
837
5076a392
FC
838=head2 Omitting a space between a regular expression and subsequent word
839
18139a1b
FC
840Omitting a space between a regular expression operator or
841its modifiers and the following word is deprecated. For
842example, C<< m/foo/sand $bar >> will still be parsed
843as C<< m/foo/s and $bar >> but will issue a warning.
5076a392 844
e683df94
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845=head2 C<\cI<X>>
846
847The backslash-c construct was designed as a way of specifying
848non-printable characters, but there were no restrictions (on ASCII
849platforms) on what the character following the C<c> could be. Now,
850a deprecation warning is raised if that character isn't an ASCII character.
851Also, a deprecation warning is raised for C<"\c{"> (which is the same
852as simply saying C<";">).
853
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KW
854=head2 C<"\b{"> and C<"\B{">
855
856In regular expressions, a literal C<"{"> immediately following a C<"\b">
857(not in a bracketed character class) or a C<"\B{"> is now deprecated
858to allow for its future use by Perl itself.
859
5076a392
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860=head2 Deprecation warning added for deprecated-in-core .pl libs
861
862This is a mandatory warning, not obeying -X or lexical warning bits.
863The warning is modelled on that supplied by deprecate.pm for
864deprecated-in-core .pm libraries. It points to the specific CPAN
823d0e46
FC
865distribution that contains the .pl libraries. The CPAN version, of
866course, does not generate the warning.
5076a392
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867
868=head2 List assignment to C<$[>
869
823d0e46
FC
870Assignment to C<$[> was deprecated and started to give warnings in
871Perl version 5.12.0. This version of perl also starts to emit a warning when
872assigning to C<$[> in list context. This fixes an oversight in 5.12.0.
5076a392
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873
874=head2 Use of qw(...) as parentheses
875
876Historically the parser fooled itself into thinking that C<qw(...)> literals
877were always enclosed in parentheses, and as a result you could sometimes omit
878parentheses around them:
879
880 for $x qw(a b c) { ... }
881
882The parser no longer lies to itself in this way. Wrap the list literal in
823d0e46 883parentheses, like this:
5076a392
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884
885 for $x (qw(a b c)) { ... }
886
887=head2 C<\N{BELL}> is deprecated
888
889This is because Unicode is using that name for a different character.
890See L</Unicode Version 6.0 is now supported (mostly)> for more
891explanation.
892
893=head2 C<?PATTERN?> is deprecated
894
895C<?PATTERN?> (without the initial m) has been deprecated and now produces
896a warning. This is to allow future use of C<?> in new operators.
897The match-once functionality is still available in the form of C<m?PATTERN?>.
898
5076a392
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899=head2 Tie functions on scalars holding typeglobs
900
901Calling a tie function (C<tie>, C<tied>, C<untie>) with a scalar argument
902acts on a file handle if the scalar happens to hold a typeglob.
903
904This is a long-standing bug that will be removed in Perl 5.16, as
905there is currently no way to tie the scalar itself when it holds
906a typeglob, and no way to untie a scalar that has had a typeglob
907assigned to it.
908
823d0e46 909Now there is a deprecation warning whenever a tie
5076a392
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910function is used on a handle without an explicit C<*>.
911
18139a1b 912=head2 User-defined case-mapping
5076a392 913
18139a1b
FC
914This feature is being deprecated due to its many issues, as documented in
915L<perlunicode/User-Defined Case Mappings (for serious hackers only)>.
e48f36f0
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916It is planned to remove this feature in Perl 5.16. Instead use the CPAN module
917L<Unicode::Casing>, which provides improved functionality.
823d0e46 918
18139a1b 919=head2 Deprecated modules
5076a392
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920
921The following modules will be removed from the core distribution in a
922future release, and should be installed from CPAN instead. Distributions
923on CPAN which require these should add them to their prerequisites. The
823d0e46 924core versions of these modules will issue a deprecation warning.
5076a392
FC
925
926If you ship a packaged version of Perl, either alone or as part of a
927larger system, then you should carefully consider the repercussions of
823d0e46 928core module deprecations. You may want to consider shipping your default
5076a392 929build of Perl with packages for some or all deprecated modules which
823d0e46 930install into C<vendor> or C<site> perl library directories. This will
5076a392
FC
931inhibit the deprecation warnings.
932
933Alternatively, you may want to consider patching F<lib/deprecate.pm>
934to provide deprecation warnings specific to your packaging system
935or distribution of Perl, consistent with how your packaging system
936or distribution manages a staged transition from a release where the
937installation of a single package provides the given functionality, to
938a later release where the system administrator needs to know to install
939multiple packages to get that same functionality.
940
941You can silence these deprecation warnings by installing the modules
942in question from CPAN. To install the latest version of all of them,
943just install C<Task::Deprecations::5_14>.
944
945=over
946
947=item L<Devel::DProf>
948
949We strongly recommend that you install and used L<Devel::NYTProf> in
950preference, as it offers significantly improved profiling and reporting.
951
952=back
953
5076a392
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954=head1 Performance Enhancements
955
54c7bb16 956=head2 "Safe signals" optimisation
df91d470
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957
958Signal dispatch has been moved from the runloop into control ops. This
959should give a few percent speed increase, and eliminates almost all of
960the speed penalty caused by the introduction of "safe signals" in
9615.8.0. Signals should still be dispatched within the same statement as
962they were previously - if this is not the case, or it is possible to
963create uninterruptible loops, this is a bug, and reports are encouraged
964of how to recreate such issues.
965
54c7bb16 966=head2 Optimisation of shift; and pop; calls without arguments
df91d470 967
111b6aa7
FC
968Two fewer OPs are used for shift and pop calls with no argument (with
969implicit C<@_>). This change makes C<shift;> 5% faster than C<shift @_;>
970on non-threaded perls and 25% faster on threaded.
df91d470 971
fa232254 972=head2 Optimisation of regexp engine string comparison work
df91d470 973
fa232254
FC
974The foldEQ_utf8 API function for case-insensitive comparison of strings (which
975is used heavily by the regexp engine) was substantially refactored and
976optimised - and its documentation much improved as a free bonus gift.
df91d470 977
fa232254 978=head2 Regular expression compilation speed-up
df91d470 979
fa232254
FC
980Compiling regular expressions has been made faster for the case where upgrading
981the regex to utf8 is necessary but that isn't known when the compilation begins.
df91d470 982
fa232254 983=head2 String appending is 100 times faster
df91d470 984
fa232254
FC
985When doing a lot of string appending, perl could end up allocating a lot more
986memory than needed in a very inefficient way, if perl was configured to use the
987system's C<malloc> implementation instead of its own.
988
989C<sv_grow>, which is what's being used to allocate more memory if necessary
990when appending to a string, has now been taught how to round up the memory
991it requests to a certain geometric progression, making it much faster on
992certain platforms and configurations. On Win32, it's now about 100 times
993faster.
994
995=head2 Eliminate C<PL_*> accessor functions under ithreads
996
997When C<MULTIPLICITY> was first developed, and interpreter state moved into
998an interpreter struct, thread and interpreter local C<PL_*> variables were
999defined as macros that called accessor functions, returning the address of
1000the value, outside of the perl core. The intent was to allow members
1001within the interpreter struct to change size without breaking binary
1002compatibility, so that bug fixes could be merged to a maintenance branch
1003that necessitated such a size change.
1004
1005However, some non-core code defines C<PERL_CORE>, sometimes intentionally
1006to bypass this mechanism for speed reasons, sometimes for other reasons but
1007with the inadvertent side effect of bypassing this mechanism. As some of
1008this code is widespread in production use, the result is that the core
1009I<can't> change the size of members of the interpreter struct, as it will
1010break such modules compiled against a previous release on that maintenance
1011branch. The upshot is that this mechanism is redundant, and well-behaved
1012code is penalised by it. Hence it can and should be removed (and has
1013been).
1014
1015=head2 Freeing weak references
1016
1017When an object has many weak references to it, freeing that object
1018can under some some circumstances take O(N^2) time to free (where N is the
1019number of references). The number of circumstances has been reduced
1020[perl #75254]
1021
1022=head2 Lexical array and hash assignments
1023
1024An earlier optimisation to speed up C<my @array = ...> and
1025C<my %hash = ...> assignments caused a bug and was disabled in Perl 5.12.0.
1026
1027Now we have found another way to speed up these assignments [perl #82110].
df91d470 1028
111b6aa7 1029=head2 C<@_> uses less memory
df91d470 1030
111b6aa7
FC
1031Previously, C<@_> was allocated for every subroutine at compile time with
1032enough space for four entries. Now this allocation is done on demand when
1033the subroutine is called [perl #72416].
5076a392 1034
5076a392
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1035=head2 Size optimisations to SV and HV structures
1036
1037xhv_fill has been eliminated from struct xpvhv, saving 1 IV per hash and
111b6aa7 1038on some systems will cause struct xpvhv to become cache-aligned. To avoid
5076a392
FC
1039this memory saving causing a slowdown elsewhere, boolean use of HvFILL
1040now calls HvTOTALKEYS instead (which is equivalent) - so while the fill
111b6aa7
FC
1041data when actually required are now calculated on demand, the cases when
1042this needs to be done should be few and far between.
5076a392 1043
111b6aa7
FC
1044The order of structure elements in SV bodies has changed. Effectively,
1045the NV slot has swapped location with STASH and MAGIC. As all access to
1046SV members is via macros, this should be completely transparent. This
5076a392
FC
1047change allows the space saving for PVHVs documented above, and may reduce
1048the memory allocation needed for PVIVs on some architectures.
1049
fa232254
FC
1050C<XPV>, C<XPVIV>, and C<XPVNV> now only allocate the parts of the C<SV> body
1051they actually use, saving some space.
5076a392 1052
fa232254
FC
1053Scalars containing regular expressions now only allocate the part of the C<SV>
1054body they actually use, saving some space.
5076a392
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1055
1056=head2 Memory consumption improvements to Exporter
1057
1058The @EXPORT_FAIL AV is no longer created unless required, hence neither is
111b6aa7
FC
1059the typeglob backing it. This saves about 200 bytes for every package that
1060uses Exporter but doesn't use this functionality.
5076a392 1061
111b6aa7 1062=head2 Memory savings for weak references
5076a392
FC
1063
1064For weak references, the common case of just a single weak reference per
1065referent has been optimised to reduce the storage required. In this case it
111b6aa7 1066saves the equivalent of one small Perl array per referent.
5076a392 1067
111b6aa7 1068=head2 C<%+> and C<%-> use less memory
5076a392
FC
1069
1070The bulk of the C<Tie::Hash::NamedCapture> module used to be in the perl
111b6aa7 1071core. It has now been moved to an XS module, to reduce the overhead for
5076a392
FC
1072programs that do not use C<%+> or C<%->.
1073
fa232254 1074=head2 Multiple small improvements to threads
5076a392 1075
fa232254
FC
1076The internal structures of threading now make fewer API calls and fewer
1077allocations, resulting in noticeably smaller object code. Additionally,
1078many thread context checks have been deferred so that they're only done
1079when required (although this is only possible for non-debugging builds).
5076a392 1080
fa232254 1081=head2 Adjacent pairs of nextstate opcodes are now optimized away
5076a392 1082
fa232254 1083Previously, in code such as
5076a392 1084
fa232254 1085 use constant DEBUG => 0;
5076a392 1086
fa232254
FC
1087 sub GAK {
1088 warn if DEBUG;
1089 print "stuff\n";
1090 }
5076a392 1091
fa232254
FC
1092the ops for C<warn if DEBUG;> would be folded to a C<null> op (C<ex-const>), but
1093the C<nextstate> op would remain, resulting in a runtime op dispatch of
1094C<nextstate>, C<nextstate>, ....
5076a392 1095
fa232254
FC
1096The execution of a sequence of C<nextstate> ops is indistinguishable from just
1097the last C<nextstate> op so the peephole optimizer now eliminates the first of
1098a pair of C<nextstate> ops, except where the first carries a label, since labels
1099must not be eliminated by the optimizer and label usage isn't conclusively known
1100at compile time.
5076a392
FC
1101
1102=head1 Modules and Pragmata
1103
1104=head2 New Modules and Pragmata
1105
1106=over 4
1107
1108=item *
1109
1110C<CPAN::Meta::YAML> 0.003 has been added as a dual-life module. It supports a
1111subset of YAML sufficient for reading and writing META.yml and MYMETA.yml files
1112included with CPAN distributions or generated by the module installation
1113toolchain. It should not be used for any other general YAML parsing or
1114generation task.
1115
1116=item *
1117
1118C<CPAN::Meta> version 2.110440 has been added as a dual-life module. It
1119provides a standard library to read, interpret and write CPAN distribution
1120metadata files (e.g. META.json and META.yml) which describes a
1121distribution, its contents, and the requirements for building it and
1122installing it. The latest CPAN distribution metadata specification is
1123included as C<CPAN::Meta::Spec> and notes on changes in the specification
1124over time are given in C<CPAN::Meta::History>.
1125
1126=item *
1127
5a553547 1128C<HTTP::Tiny> 0.011 has been added as a dual-life module. It is a very
5076a392
FC
1129small, simple HTTP/1.1 client designed for simple GET requests and file
1130mirroring. It has has been added to enable CPAN.pm and CPANPLUS to
1131"bootstrap" HTTP access to CPAN using pure Perl without relying on external
1132binaries like F<curl> or F<wget>.
1133
1134=item *
1135
1136C<JSON::PP> 2.27105 has been added as a dual-life module, for the sake of
1137reading F<META.json> files in CPAN distributions.
1138
1139=item *
1140
21ef4e45 1141C<Module::Metadata> 1.000004 has been added as a dual-life module. It gathers
5076a392
FC
1142package and POD information from Perl module files. It is a standalone module
1143based on Module::Build::ModuleInfo for use by other module installation
1144toolchain components. Module::Build::ModuleInfo has been deprecated in
1145favor of this module instead.
1146
1147=item *
1148
1149C<Perl::OSType> 1.002 has been added as a dual-life module. It maps Perl
1150operating system names (e.g. 'dragonfly' or 'MSWin32') to more generic types
1151with standardized names (e.g. "Unix" or "Windows"). It has been refactored
1152out of Module::Build and ExtUtils::CBuilder and consolidates such mappings into
1153a single location for easier maintenance.
1154
1155=item *
1156
1157The following modules were added by the C<Unicode::Collate>
1158upgrade. See below for details.
1159
1160C<Unicode::Collate::CJK::Big5>
1161
1162C<Unicode::Collate::CJK::GB2312>
1163
1164C<Unicode::Collate::CJK::JISX0208>
1165
1166C<Unicode::Collate::CJK::Korean>
1167
1168C<Unicode::Collate::CJK::Pinyin>
1169
1170C<Unicode::Collate::CJK::Stroke>
1171
1172=item *
1173
1174C<Version::Requirements> version 0.101020 has been added as a dual-life
1175module. It provides a standard library to model and manipulates module
1176prerequisites and version constraints as defined in the L<CPAN::Meta::Spec>.
1177
1178=back
1179
a5794e94 1180=head2 Updated Modules and Pragma
5076a392
FC
1181
1182=over 4
1183
1184=item *
1185
81a53be2
FR
1186C<attributes> has been upgraded from version 0.12 to 0.14.
1187
1188=item *
1189
5076a392
FC
1190C<Archive::Extract> has been upgraded from version 0.38 to 0.48.
1191
1192Updates since 0.38 include: a safe print method that guards
1193Archive::Extract from changes to $\; a fix to the tests when run in core
1984204c
FC
1194perl; support for TZ files; a modification for the lzma
1195logic to favour IO::Uncompress::Unlzma; and a fix
1196for an issue with NetBSD-current and its new unzip
5076a392
FC
1197executable.
1198
1199=item *
1200
1201C<Archive::Tar> has been upgraded from version 1.54 to 1.76.
1202
1984204c
FC
1203Important changes since 1.54 include the following:
1204
1205=over
1206
1207=item *
1208
1209Compatibility with busybox implementations of tar
1210
1211=item *
1212
1213A fix so that C<write()> and C<create_archive()>
1214close only handles they opened
1215
1216=item *
1217
1218A bug was fixed regarding the exit code of extract_archive.
5076a392 1219
1984204c
FC
1220=item *
1221
4f978a3b 1222The C<ptar> utility has a new option to allow safe
5076a392
FC
1223creation of tarballs without world-writable files on Windows, allowing those
1224archives to be uploaded to CPAN.
1225
1984204c
FC
1226=item *
1227
1228A new ptargrep utility for using regular expressions against
5076a392
FC
1229the contents of files in a tar archive.
1230
1984204c
FC
1231=item *
1232
1233Pax extended headers are now skipped.
1234
1235=back
5076a392
FC
1236
1237=item *
1238
fcd5df6d
FR
1239C<Attribute::Handlers> has been upgraded from version 0.87 to 0.89.
1240
1241=item *
1242
3f5a47e4
FR
1243C<autodie> has been upgraded from version 2.06_01 to 2.1001.
1244
1245=item *
1246
578e7c9d
FR
1247C<AutoLoader> has been upgraded from version 5.70 to 5.71.
1248
1249=item *
1250
a13baafd 1251C<B> has been upgraded from version 1.23 to 1.29.
5076a392
FC
1252
1253It no longer crashes when taking apart a C<y///> containing characters
1254outside the octet range or compiled in a C<use utf8> scope.
1255
1256The size of the shared object has been reduced by about 40%, with no
1257reduction in functionality.
1258
1259=item *
1260
4a75fbf5 1261C<B::Concise> has been upgraded from version 0.78 to 0.83.
5076a392
FC
1262
1263B::Concise marks rv2sv, rv2av and rv2hv ops with the new OPpDEREF flag
1264as "DREFed".
1265
1266It no longer produces mangled output with the C<-tree> option
1267[perl #80632].
1268
1269=item *
1270
6bb8c1e3
FR
1271C<B::Debug> has been upgraded from version 1.12 to 1.16.
1272
1273=item *
1274
c67a4e29 1275C<B::Deparse> has been upgraded from version 0.96 to 1.03.
5076a392 1276
1984204c 1277The deparsing of a nextstate op has changed when it has both a
5076a392
FC
1278change of package (relative to the previous nextstate), or a change of
1279C<%^H> or other state, and a label. Previously the label was emitted
cdc10f43 1280first, but now the label is emitted last (5.12.1).
5076a392 1281
5a553547
FC
1282The C<no 5.13.2> or similar form is now correctly handled by B::Deparse
1283(5.12.3).
5076a392
FC
1284
1285B::Deparse now properly handles the code that applies a conditional
1286pattern match against implicit C<$_> as it was fixed in [perl #20444].
1287
1984204c
FC
1288Deparsing of C<our> followed by a variable with funny characters
1289(as permitted under the C<utf8> pragma) has also been fixed [perl #33752].
5076a392
FC
1290
1291=item *
1292
d97c5d3b
FR
1293C<B::Lint> has been upgraded from version 1.11_01 to 1.13.
1294
1295=item *
1296
5aef2c44
FR
1297C<base> has been upgraded from version 2.15 to 2.16.
1298
1299=item *
1300
e539ae69
FR
1301C<bignum> has been upgraded from version 0.23 to 0.26.
1302
1303=item *
1304
c74c1fa8 1305C<Carp> has been upgraded from version 1.15 to 1.20.
5076a392
FC
1306
1307L<Carp> now detects incomplete L<caller()|perlfunc/"caller EXPR"> overrides and
d430b8e7
FC
1308avoids using bogus C<@DB::args>. To provide backtraces,
1309Carp relies on particular behaviour of the C<caller>
1310built-in. Carp now detects if other code has
5076a392 1311overridden this with an incomplete implementation, and modifies its backtrace
d430b8e7
FC
1312accordingly. Previously incomplete overrides would cause incorrect values
1313in backtraces (best case), or obscure fatal errors (worst case).
5076a392
FC
1314
1315This fixes certain cases of C<Bizarre copy of ARRAY> caused by modules
d430b8e7 1316overriding C<caller()> incorrectly (5.12.2).
5076a392 1317
1984204c 1318It now also avoids using regular expressions that cause perl to
5076a392
FC
1319load its Unicode tables, in order to avoid the 'BEGIN not safe after
1320errors' error that will ensue if there has been a syntax error
1321[perl #82854].
1322
1323=item *
1324
9eb7ad55 1325C<CGI> has been upgraded from version 3.48 to 3.52.
5076a392
FC
1326
1327This provides the following security fixes: the MIME boundary in
1984204c
FC
1328multipart_init is now random and the handling of
1329newlines embedded in header values has been improved.
5076a392
FC
1330
1331=item *
1332
5076a392
FC
1333C<Compress::Raw::Bzip2> has been upgraded from version 2.024 to 2.033.
1334
1984204c 1335It has been updated to use bzip2 1.0.6.
5076a392
FC
1336
1337=item *
1338
51090521
FR
1339C<Compress::Raw::Zlib> has been upgraded from version 2.024 to 2.033.
1340
1341=item *
1342
f75b7efc 1343C<CPAN> has been upgraded from version 1.94_56 to 1.9600.
1984204c
FC
1344
1345Major highlights:
5076a392
FC
1346
1347=over 4
1348
1984204c 1349=item * much less configuration dialog hassle
5076a392 1350
1984204c 1351=item * support for META/MYMETA.json
5076a392 1352
1984204c 1353=item * support for local::lib
5076a392 1354
1984204c 1355=item * support for HTTP::Tiny to reduce the dependency on ftp sites
5076a392 1356
1984204c 1357=item * automatic mirror selection
5076a392 1358
1984204c 1359=item * iron out all known bugs in configure_requires
5076a392 1360
1984204c
FC
1361=item * support for distributions compressed with bzip2
1362
1363=item * allow Foo/Bar.pm on the commandline to mean Foo::Bar
1364
1365=back
5076a392
FC
1366
1367=item *
1368
d430b8e7
FC
1369C<CPANPLUS> has been upgraded from version 0.90 to 0.9103.
1370
1371A change to F<cpanp-run-perl>
1372resolves L<RT #55964|http://rt.cpan.org/Public/Bug/Display.html?id=55964>
1373and L<RT #57106|http://rt.cpan.org/Public/Bug/Display.html?id=57106>, both
1374of which related to failures to install distributions that use
1375C<Module::Install::DSL> (5.12.2).
5076a392 1376
1984204c
FC
1377A dependency on Config was not recognised as a
1378core module dependency. This has been fixed.
5076a392 1379
1984204c 1380CPANPLUS now includes support for META.json and MYMETA.json.
5076a392
FC
1381
1382=item *
1383
4467e8f7
FR
1384C<CPANPLUS::Dist::Build> has been upgraded from version 0.46 to 0.54.
1385
1386=item *
1387
5076a392
FC
1388C<Data::Dumper> has been upgraded from version 2.125 to 2.130_02.
1389
4ed2cea4
FC
1390The indentation used to be off when C<$Data::Dumper::Terse> was set. This
1391has been fixed [perl #73604].
1392
1984204c
FC
1393This upgrade also fixes a crash when using custom sort functions that might
1394cause the stack to change [perl #74170].
5076a392
FC
1395
1396C<Dumpxs> no longer crashes with globs returned by C<*$io_ref>
1397[perl #72332].
1398
1399=item *
1400
549d34f5
FR
1401C<DB_File> has been upgraded from version 1.820 to 1.821.
1402
1403=item *
1404
5076a392
FC
1405C<Devel::DProf> has been upgraded from version 20080331.00 to 20110228.00.
1406
1407Merely loading C<Devel::DProf> now no longer triggers profiling to start.
1408C<use Devel::DProf> and C<perl -d:DProf ...> still behave as before and start
1409the profiler.
1410
1411NOTE: C<Devel::DProf> is deprecated and will be removed from a future
1984204c 1412version of Perl. We strongly recommend that you install and use
5076a392
FC
1413L<Devel::NYTProf> instead, as it offers significantly improved
1414profiling and reporting.
1415
1416=item *
1417
868625d2
FR
1418C<Devel::Peek> has been upgraded from version 1.04 to 1.07.
1419
1420=item *
1421
66899ca3
FR
1422C<Devel::SelfStubber> has been upgraded from version 1.03 to 1.05.
1423
1424=item *
1425
5076a392
FC
1426C<diagnostics> has been upgraded from version 1.19 to 1.22.
1427
1428It now renders pod links slightly better, and has been taught to find
1429descriptions for messages that share their descriptions with other
1430messages.
1431
1432=item *
1433
1434C<Digest::MD5> has been upgraded from version 2.39 to 2.51.
1435
1436It is now safe to use this module in combination with threads.
1437
1438=item *
1439
1440C<Digest::SHA> has been upgraded from version 5.47 to 5.61.
1441
1442C<shasum> now more closely mimics C<sha1sum>/C<md5sum>.
1443
1444C<Addfile> accepts all POSIX filenames.
1445
1984204c
FC
1446New SHA-512/224 and SHA-512/256 transforms (ref. NIST Draft FIPS 180-4
1447[February 2011])
5076a392
FC
1448
1449=item *
1450
e53cbaa3
FR
1451C<Dumpvalue> has been upgraded from version 1.13 to 1.16.
1452
1453=item *
1454
31e8b85a 1455C<DynaLoader> has been upgraded from version 1.10 to 1.13.
5076a392
FC
1456
1457It fixes a buffer overflow when passed a very long file name.
1458
1459It no longer inherits from AutoLoader; hence it no longer
1460produces weird error messages for unsuccessful method calls on classes that
1461inherit from DynaLoader [perl #84358].
1462
1463=item *
1464
1465C<Encode> has been upgraded from version 2.39 to 2.42.
1466
1467Now, all 66 Unicode non-characters are treated the same way U+FFFF has
1984204c
FC
1468always been treated; in cases when it was disallowed, all 66 are
1469disallowed; in those cases where it warned, all 66 warn.
5076a392
FC
1470
1471=item *
1472
68f90ac3
FR
1473C<Env> has been upgraded from version 1.01 to 1.02.
1474
1475=item *
1476
5076a392
FC
1477C<Errno> has been upgraded from version 1.11 to 1.13.
1478
1479The implementation of C<Errno> has been refactored to use about 55% less memory.
5076a392
FC
1480
1481On some platforms with unusual header files, like Win32/gcc using mingw64
1482headers, some constants which weren't actually error numbers have been exposed
1483by C<Errno>. This has been fixed [perl #77416].
1484
1485=item *
1486
1487C<Exporter> has been upgraded from version 5.64_01 to 5.64_03.
1488
1489Exporter no longer overrides C<$SIG{__WARN__}> [perl #74472]
1490
1491=item *
1492
25fe7f8f
FR
1493C<ExtUtils::CBuilder> has been upgraded from version 0.27 to 0.280202.
1494
1495=item *
1496
2292e71e
FR
1497C<ExtUtils::Command> has been upgraded from version 1.16 to 1.17.
1498
1499=item *
1500
5076a392
FC
1501C<ExtUtils::Constant> has been upgraded from 0.22 to 0.23.
1502
1503The C<AUTOLOAD> helper code generated by C<ExtUtils::Constant::ProxySubs>
1504can now C<croak> for missing constants, or generate a complete C<AUTOLOAD>
1984204c
FC
1505subroutine in XS, allowing simplification of many modules that use it
1506(C<Fcntl>, C<File::Glob>, C<GDBM_File>, C<I18N::Langinfo>, C<POSIX>,
1507C<Socket>).
5076a392
FC
1508
1509C<ExtUtils::Constant::ProxySubs> can now optionally push the names of all
1984204c 1510constants onto the package's C<@EXPORT_OK>.
5076a392
FC
1511
1512=item *
1513
588c5853
FR
1514C<ExtUtils::Install> has been upgraded from version 1.55 to 1.56.
1515
1516=item *
1517
5418ffb3
FR
1518C<ExtUtils::MakeMaker> has been upgraded from version 6.56 to 6.57_05.
1519
1520=item *
1521
f40ab45f
FR
1522C<ExtUtils::Manifest> has been upgraded from version 1.57 to 1.58.
1523
1524=item *
1525
b7064dd7
FR
1526C<ExtUtils::ParseXS> has been upgraded from version 2.21 to 2.2209.
1527
1528=item *
1529
8b87be80
FR
1530C<Fcntl> has been upgraded from version 1.06 to 1.11.
1531
1532=item *
1533
05102622
FR
1534C<File::CheckTree> has been upgraded from version 4.4 to 4.41.
1535
1536=item *
1537
e12786fa 1538C<File::DosGlob> has been upgraded from version 1.01 to 1.04.
5076a392
FC
1539
1540It allows patterns containing literal parentheses (they no longer need to
1984204c
FC
1541be escaped). On Windows, it no longer
1542adds an extra F<./> to the file names
5076a392
FC
1543returned when the pattern is a relative glob with a drive specification,
1544like F<c:*.pl> [perl #71712].
1545
1546=item *
1547
1548C<File::Fetch> has been upgraded from version 0.24 to 0.32.
1549
1550C<HTTP::Lite> is now supported for 'http' scheme.
1551
1552The C<fetch> utility is supported on FreeBSD, NetBSD and
1553Dragonfly BSD for the C<http> and C<ftp> schemes.
1554
1555=item *
1556
23f2cbb1 1557C<File::Find> has been upgraded from version 1.15 to 1.19.
5076a392 1558
1984204c 1559It improves handling of backslashes on Windows, so that paths like
5076a392
FC
1560F<c:\dir\/file> are no longer generated [perl #71710].
1561
1562=item *
1563
0ae9f678
FR
1564C<File::Glob> has been upgraded from version 1.07 to 1.12.
1565
1566=item *
1567
d430b8e7
FC
1568C<File::Spec> has been upgraded from version 3.31 to 3.33.
1569
1570Several portability fixes were made in C<File::Spec::VMS>: a colon is now
1571recognized as a delimiter in native filespecs; caret-escaped delimiters are
1572recognized for better handling of extended filespecs; C<catpath()> returns
1573an empty directory rather than the current directory if the input directory
1574name is empty; C<abs2rel()> properly handles Unix-style input (5.12.2).
1575
1576=item *
1577
46ba0657 1578C<File::stat> has been upgraded from 1.02 to 1.05.
5076a392
FC
1579
1580The C<-x> and C<-X> file test operators now work correctly under the root
1581user.
1582
1583=item *
1584
b7edcc3c
FR
1585C<Filter::Simple> has been upgraded from version 0.84 to 0.86.
1586
1587=item *
1588
dc6857fd 1589C<GDBM_File> has been upgraded from 1.10 to 1.14.
5076a392
FC
1590
1591This fixes a memory leak when DBM filters are used.
1592
1593=item *
1594
6e107b45 1595C<Hash::Util> has been upgraded from 0.07 to 0.11.
5076a392 1596
1984204c
FC
1597Hash::Util no longer emits spurious "uninitialized" warnings when
1598recursively locking hashes that have undefined values [perl #74280].
5076a392
FC
1599
1600=item *
1601
89ce9b34
FR
1602C<Hash::Util::FieldHash> has been upgraded from version 1.04 to 1.09.
1603
1604=item *
1605
eec33fe6
FR
1606C<I18N::Collate> has been upgraded from version 1.01 to 1.02.
1607
1608=item *
1609
ad5f8f47 1610C<I18N::Langinfo> has been upgraded from version 0.03 to 0.08.
5076a392
FC
1611
1612C<langinfo()> now defaults to using C<$_> if there is no argument given, just
5334145a 1613as the documentation has always claimed.
5076a392
FC
1614
1615=item *
1616
c41635f7
FR
1617C<I18N::LangTags> has been upgraded from version 0.35 to 0.35_01.
1618
1619=item *
1620
98a6a4ff
FR
1621C<if> has been upgraded from version 0.05 to 0.0601.
1622
1623=item *
1624
f6ff7fb6
FR
1625C<IO> has been upgraded from version 1.25_02 to 1.25_04.
1626
1627=item *
1628
d13528c5 1629C<IO::Select> has been upgraded from version 1.17 to 1.20.
5076a392
FC
1630
1631It now allows IO::Handle objects (and objects in derived classes) to be
1632removed from an IO::Select set even if the underlying file descriptor is
1633closed or invalid.
1634
1635=item *
1636
d07561d3 1637C<IPC::Cmd> has been upgraded from version 0.54 to 0.70.
5076a392 1638
1984204c
FC
1639Resolves an issue with splitting Win32 command lines. An argument
1640consisting of the single character "0" used to be omitted (CPAN RT #62961).
5076a392
FC
1641
1642=item *
1643
3f16e4eb 1644C<IPC::Open3> has been upgraded from 1.05 to 1.09.
5076a392 1645
4ed2cea4
FC
1646C<open3> now produces an error if the C<exec> call fails, allowing this
1647condition to be distinguished from a child process that exited with a
1648non-zero status [perl #72016].
1649
5076a392
FC
1650The internal C<xclose> routine now knows how to handle file descriptors, as
1651documented, so duplicating STDIN in a child process using its file
1652descriptor now works [perl #76474].
1653
1654=item *
1655
c8b41807
FR
1656C<IPC::SysV> has been upgraded from version 2.01 to 2.03.
1657
1658=item *
1659
ef79f038
FR
1660C<lib> has been upgraded from version 0.62 to 0.63.
1661
1662=item *
1663
5b1884f4 1664C<Locale::Maketext> has been upgraded from version 1.14 to 1.19.
5076a392 1665
1984204c 1666Locale::Maketext now supports external caches.
5076a392 1667
1984204c
FC
1668This upgrade also fixes an infinite loop in
1669C<Locale::Maketext::Guts::_compile()> when
5076a392
FC
1670working with tainted values (CPAN RT #40727).
1671
1984204c 1672C<< ->maketext >> calls will now back up and restore C<$@> so that error
5076a392
FC
1673messages are not suppressed (CPAN RT #34182).
1674
1675=item *
1676
3811bd2b
FR
1677C<Log::Message> has been upgraded from version 0.02 to 0.04.
1678
1679=item *
1680
8eb65377
FR
1681C<Log::Message::Simple> has been upgraded from version 0.06 to 0.08.
1682
1683=item *
1684
5076a392
FC
1685C<Math::BigInt> has been upgraded from version 1.89_01 to 1.994.
1686
1687This fixes, among other things, incorrect results when computing binomial
1688coefficients [perl #77640].
1689
1984204c 1690It also prevents C<sqrt($int)> from crashing under C<use bigrat;>
5076a392
FC
1691[perl #73534].
1692
1693=item *
1694
846c1cec
FR
1695C<Math::BigInt::FastCalc> has been upgraded from version 0.19 to 0.28.
1696
1697=item *
1698
fce4aef3
FR
1699C<Math::BigRat> has been upgraded from version 0.24 to 0.26_02.
1700
1701=item *
1702
12e26027
FR
1703C<Memoize> has been upgraded from version 1.01_03 to 1.02.
1704
1705=item *
1706
5076a392
FC
1707C<MIME::Base64> has been upgraded from 3.08 to 3.13.
1708
1709Includes new functions to calculate the length of encoded and decoded
1710base64 strings.
1711
1712Now provides C<encode_base64url> and C<decode_base64url> functions to process
1713the base64 scheme for "URL applications".
1714
1715=item *
1716
1717C<Module::Build> has been upgraded from version 0.3603 to 0.3800.
1718
1719A notable change is the deprecation of several modules.
1720Module::Build::Version has been deprecated and Module::Build now relies
1721directly upon L<version>. Module::Build::ModuleInfo has been deprecated in
1722favor of a standalone copy of it called L<Module::Metadata>.
1723Module::Build::YAML has been deprecated in favor of L<CPAN::Meta::YAML>.
1724
1725Module::Build now also generates META.json and MYMETA.json files
1726in accordance with version 2 of the CPAN distribution metadata specification,
1727L<CPAN::Meta::Spec>. The older format META.yml and MYMETA.yml files are
1728still generated, as well.
1729
1730=item *
1731
7259fe26 1732C<Module::CoreList> has been upgraded from version 2.29 to 2.47.
5076a392
FC
1733
1734Besides listing the updated core modules of this release, it also stops listing
1984204c 1735the C<Filespec> module. That module never existed in core. The scripts
5076a392 1736generating C<Module::CoreList> confused it with C<VMS::Filespec>, which actually
1984204c 1737is a core module as of perl 5.8.7.
5076a392
FC
1738
1739=item *
1740
193af05b
FR
1741C<Module::Load> has been upgraded from version 0.16 to 0.18.
1742
1743=item *
1744
5b3a054f
FR
1745C<Module::Load::Conditional> has been upgraded from version 0.34 to 0.44.
1746
1747=item *
1748
01835e3a
FR
1749C<mro> has been upgraded from version 1.02 to 1.07.
1750
1751=item *
1752
bfe7bf96 1753C<NDBM_File> has been upgraded from version 1.08 to 1.12.
4f978a3b
FR
1754
1755This fixes a memory leak when DBM filters are used.
1756
1757=item *
1758
d0aa5c91
FR
1759C<Net::Ping> has been upgraded from version 2.36 to 2.38.
1760
1761=item *
1762
d44b8a8c
FR
1763C<NEXT> has been upgraded from version 0.64 to 0.65.
1764
1765=item *
1766
678d4fd4
FR
1767C<Object::Accessor> has been upgraded from version 0.36 to 0.38.
1768
1769=item *
1770
34188656 1771C<ODBM_File> have been upgraded from version 1.07 to 1.10.
5076a392
FC
1772
1773This fixes a memory leak when DBM filters are used.
1774
1775=item *
1776
4c69840c
FR
1777C<Opcode> has been upgraded from version 1.15 to 1.18.
1778
1779=item *
1780
77be713d 1781C<overload> has been upgraded from 1.10 to 1.12.
5076a392
FC
1782
1783C<overload::Method> can now handle subroutines that are themselves blessed
1784into overloaded classes [perl #71998].
1785
5076a392
FC
1786The documentation has greatly improved. See L</Documentation> below.
1787
1788=item *
1789
f84c796e
FR
1790C<Params::Check> has been upgraded from version 0.26 to 0.28.
1791
1792=item *
1793
550ee92b
FR
1794C<parent> has been upgraded from version 0.223 to 0.225.
1795
1796=item *
1797
5076a392
FC
1798C<Parse::CPAN::Meta> has been upgraded from version 1.40 to 1.4401.
1799
1984204c 1800The latest Parse::CPAN::Meta can now read YAML and JSON files using
5076a392
FC
1801L<CPAN::Meta::YAML> and L<JSON::PP>, which are now part of the Perl core.
1802
1803=item *
1804
e981cf86
FR
1805C<PerlIO::encoding> has been upgraded from version 0.12 to 0.14.
1806
1807=item *
1808
5076a392
FC
1809C<PerlIO::scalar> has been upgraded from 0.07 to 0.11.
1810
1811A C<read> after a C<seek> beyond the end of the string no longer thinks it
1812has data to read [perl #78716].
1813
1814=item *
1815
776f733b
FR
1816C<PerlIO::via> has been upgraded from version 0.09 to 0.11.
1817
1818=item *
1819
ae9456cc
FR
1820C<Pod::Html> has been upgraded from version 1.09 to 1.1.
1821
1822=item *
1823
be3c8498
FR
1824C<Pod::LaTeX> has been upgraded from version 0.58 to 0.59.
1825
1826=item *
1827
fd8a2e89
FR
1828C<Pod::Perldoc> has been upgraded from version 3.15_02 to 3.15_03.
1829
1830=item *
1831
5bcb6583
FR
1832C<Pod::Simple> has been upgraded from version 3.13 to 3.16.
1833
1834=item *
1835
abb8c779 1836C<POSIX> has been upgraded from 1.19 to 1.24.
5076a392
FC
1837
1838It now includes constants for POSIX signal constants.
1839
1840=item *
1841
1984204c 1842C<re> has been upgraded from version 0.11 to 0.17.
5076a392
FC
1843
1844New C<use re "/flags"> pragma
1845
5076a392 1846The C<regmust> function used to crash when called on a regular expression
1984204c 1847belonging to a pluggable engine. Now it croaks instead.
5076a392
FC
1848
1849C<regmust> no longer leaks memory.
1850
1851=item *
1852
1853C<Safe> has been upgraded from version 2.25 to 2.29.
1854
cdc10f43
FC
1855Coderefs returned by C<reval()> and C<rdo()> are now wrapped via
1856C<wrap_code_refs> (5.12.1).
1857
5076a392
FC
1858This fixes a possible infinite loop when looking for coderefs.
1859
cdc10f43 1860It adds several version::vxs::* routines to the default share.
5076a392
FC
1861
1862=item *
1863
2c19fa42
FR
1864C<SDBM_File> has been upgraded from version 1.06 to 1.09.
1865
1866=item *
1867
5076a392
FC
1868C<SelfLoader> has been upgraded from 1.17 to 1.18.
1869
1870It now works in taint mode [perl #72062].
1871
1872=item *
1873
1874C<sigtrap> has been upgraded from version 1.04 to 1.05.
1875
1876It no longer tries to modify read-only arguments when generating a
1877backtrace [perl #72340].
1878
1879=item *
1880
1984204c 1881C<Socket> has been upgraded from version 1.87 to 1.94.
5076a392 1882
1984204c 1883See L</IPv6 support>, above.
5076a392
FC
1884
1885=item *
1886
1887C<Storable> has been upgraded from version 2.22 to 2.27.
1888
1889Includes performance improvement for overloaded classes.
1890
5076a392 1891This adds support for serialising code references that contain UTF-8 strings
1984204c
FC
1892correctly. The Storable minor version
1893number changed as a result, meaning that
5076a392
FC
1894Storable users who set C<$Storable::accept_future_minor> to a C<FALSE> value
1895will see errors (see L<Storable/FORWARD COMPATIBILITY> for more details).
1896
1897Freezing no longer gets confused if the Perl stack gets reallocated
1898during freezing [perl #80074].
1899
1900=item *
1901
648c3d7d
FR
1902C<Sys::Hostname> has been upgraded from version 1.11 to 1.16.
1903
1904=item *
1905
90c6e78f
FR
1906C<Term::ANSIColor> has been upgraded from version 2.02 to 3.00.
1907
1908=item *
1909
d9f2f059
FR
1910C<Term::UI> has been upgraded from version 0.20 to 0.26.
1911
1912=item *
1913
80ebb519
FR
1914C<Test::Harness> has been upgraded from version 3.17 to 3.23.
1915
1916=item *
1917
5076a392
FC
1918C<Test::Simple> has been upgraded from version 0.94 to 0.98.
1919
1920Among many other things, subtests without a C<plan> or C<no_plan> now have an
1921implicit C<done_testing()> added to them.
1922
1923=item *
1924
5076a392
FC
1925C<Thread::Semaphore> has been upgraded from version 2.09 to 2.12.
1926
1984204c
FC
1927It provides two new methods that give more control over the decrementing of
1928semaphores: C<down_nb> and C<down_force>.
5076a392
FC
1929
1930=item *
1931
f0d895e1
FR
1932C<Thread::Queue> has been upgraded from version 2.11 to 2.12.
1933
1934=item *
1935
1a6b954e
FR
1936C<threads> has been upgraded from version 1.75 to 1.83.
1937
1938=item *
1939
55816daa
FR
1940C<threads::shared> has been upgraded from version 1.32 to 1.36.
1941
1942=item *
1943
5076a392
FC
1944C<Tie::Hash> has been upgraded from version 1.03 to 1.04.
1945
1946Calling C<< Tie::Hash-E<gt>TIEHASH() >> used to loop forever. Now it C<croak>s.
1947
1948=item *
1949
f2adc546
FR
1950C<Tie::Hash::NamedCapture> has been upgraded from version 0.06 to 0.08.
1951
1952=item *
1953
ed68b07e
FR
1954C<Tie::RefHash> has been upgraded from version 1.38 to 1.39.
1955
1956=item *
1957
bb3c221a
FR
1958C<Time::HiRes> has been upgraded from version 1.9719 to 1.9721_01.
1959
1960=item *
1961
97fa568b
FR
1962C<Time::Local> has been upgraded from version 1.1901_01 to 1.2000.
1963
1964=item *
1965
a83cb732
FR
1966C<Time::Piece> has been upgraded from version 1.15_01 to 1.20_01.
1967
1968=item *
1969
5076a392
FC
1970C<Unicode::Collate> has been upgraded from version 0.52_01 to 0.73.
1971
1984204c 1972Unicode::Collate has been updated to use Unicode 6.0.0.
5076a392 1973
1984204c
FC
1974Unicode::Collate::Locale now supports a plethora of new locales: ar, be,
1975bg, de__phonebook, hu, hy, kk, mk, nso, om, tn, vi, hr, ig, ja, ko, ru, sq,
1976se, sr, to, uk, zh, zh__big5han, zh__gb2312han, zh__pinyin and zh__stroke.
5076a392
FC
1977
1978The following modules have been added:
1979
1980C<Unicode::Collate::CJK::Big5> for C<zh__big5han> which makes
1981tailoring of CJK Unified Ideographs in the order of CLDR's big5han ordering.
1982
1983C<Unicode::Collate::CJK::GB2312> for C<zh__gb2312han> which makes
1984tailoring of CJK Unified Ideographs in the order of CLDR's gb2312han ordering.
1985
1986C<Unicode::Collate::CJK::JISX0208> which makes tailoring of 6355 kanji
1987(CJK Unified Ideographs) in the JIS X 0208 order.
1988
1989C<Unicode::Collate::CJK::Korean> which makes tailoring of CJK Unified Ideographs
1990in the order of CLDR's Korean ordering.
1991
1992C<Unicode::Collate::CJK::Pinyin> for C<zh__pinyin> which makes
1993tailoring of CJK Unified Ideographs in the order of CLDR's pinyin ordering.
1994
1995C<Unicode::Collate::CJK::Stroke> for C<zh__stroke> which makes
1996tailoring of CJK Unified Ideographs in the order of CLDR's stroke ordering.
1997
5076a392
FC
1998This also sees the switch from using the pure-perl version of this
1999module to the XS version.
2000
2001=item *
2002
ec52b54b
FR
2003C<Unicode::Normalize> has been upgraded from version 1.03 to 1.10.
2004
2005=item *
2006
5076a392
FC
2007C<Unicode::UCD> has been upgraded from version 0.27 to 0.32.
2008
1984204c
FC
2009A new function, C<Unicode::UCD::num()>, has been added. This function
2010returns the numeric value of the string passed it or C<undef> if the string
2011in its entirety has no "safe" numeric value. (For more detail, and for the
2012definition of "safe", see L<Unicode::UCD/num>.)
5076a392 2013
1984204c 2014This upgrade also includes a number of bug fixes:
5076a392
FC
2015
2016=over 4
2017
2018=item charinfo()
2019
2020=over 4
2021
2022=item *
2023
2024It is now updated to Unicode Version 6 with Corrigendum #8, except,
2025as with Perl 5.14, the code point at U+1F514 has no name.
2026
2027=item *
2028
2029The Hangul syllable code points have the correct names, and their
2030decompositions are always output without requiring L<Lingua::KO::Hangul::Util>
2031to be installed.
2032
2033=item *
2034
54c7bb16
FC
2035The CJK (Chinese-Japanese-Korean) code points U+2A700 to U+2B734
2036and U+2B740 to U+2B81D are now properly handled.
5076a392
FC
2037
2038=item *
2039
2040The numeric values are now output for those CJK code points that have them.
2041
2042=item *
2043
2044The names that are output for code points with multiple aliases are now the
2045corrected ones.
2046
2047=back
2048
2049=item charscript()
2050
2051This now correctly returns "Unknown" instead of C<undef> for the script
2052of a code point that hasn't been assigned another one.
2053
2054=item charblock()
2055
2056This now correctly returns "No_Block" instead of C<undef> for the block
2057of a code point that hasn't been assigned to another one.
2058
2059=back
2060
5076a392
FC
2061=item *
2062
2063C<version> has been upgraded from 0.82 to 0.88.
2064
1984204c 2065Due to a bug, now fixed, the C<is_strict> and C<is_lax> functions did not
cdc10f43 2066work when exported (5.12.1).
5076a392
FC
2067
2068=item *
2069
3e625598 2070C<warnings> has been upgraded from version 1.09 to 1.12.
5076a392
FC
2071
2072Calling C<use warnings> without arguments is now significantly more efficient.
2073
4f978a3b
FR
2074=item *
2075
2076C<warnings::register> have been upgraded from version 1.01 to 1.02.
2077
5076a392
FC
2078It is now possible to register warning categories other than the names of
2079packages using C<warnings::register>. See L<perllexwarn> for more information.
2080
2081=item *
2082
62e270c2
FR
2083C<XSLoader> has been upgraded from version 0.10 to 0.13.
2084
2085=item *
2086
5076a392
FC
2087C<VMS::DCLsym> has been upgraded from version 1.03 to 1.05.
2088
2089Two bugs have been fixed [perl #84086]:
2090
2091The symbol table name was lost when tying a hash, due to a thinko in
2092C<TIEHASH>. The result was that all tied hashes interacted with the
2093local symbol table.
2094
2095Unless a symbol table name had been explicitly specified in the call
2096to the constructor, querying the special key ':LOCAL' failed to
2097identify objects connected to the local symbol table.
2098
2099=item *
2100
2101C<Win32> has been upgraded from version 0.39 to 0.44.
2102
1984204c
FC
2103This release has several new functions: C<Win32::GetSystemMetrics>,
2104C<Win32::GetProductInfo>, C<Win32::GetOSDisplayName>.
5076a392 2105
1984204c
FC
2106The names returned by C<Win32::GetOSName> and C<Win32::GetOSDisplayName>
2107have been corrected.
5076a392 2108
5076a392
FC
2109=back
2110
5076a392
FC
2111=head2 Removed Modules and Pragmata
2112
2113The following modules have been removed from the core distribution, and if
2114needed should be installed from CPAN instead.
2115
2116=over
2117
4f978a3b
FR
2118=item *
2119
2120C<Class::ISA> has been removed from the Perl core. Prior version was 0.36.
5076a392 2121
4f978a3b
FR
2122=item *
2123
2124C<Pod::Plainer> has been removed from the Perl core. Prior version was 1.02.
2125
2126=item *
5076a392 2127
4f978a3b 2128C<Switch> has been removed from the Perl core. Prior version was 2.16.
5076a392
FC
2129
2130=back
2131
2132The removal of C<Shell> has been deferred until after 5.14, as the
2133implementation of C<Shell> shipped with 5.12.0 did not correctly issue the
2134warning that it was to be removed from core.
2135
2136=head1 Documentation
2137
5076a392
FC
2138=head2 New Documentation
2139
41e29def 2140=head3 L<perlgpl>
5076a392
FC
2141
2142L<perlgpl> has been updated to contain GPL version 1, as is included in the
cdc10f43 2143F<README> distributed with perl (5.12.1).
5076a392 2144
41e29def 2145=head3 Perl 5.12.x delta files
5076a392 2146
41e29def
FC
2147The perldelta files for Perl 5.12.1 to 5.12.3 have been added from the
2148maintenance branch: L<perl5121delta>, L<perl5122delta>, L<perl5123delta>.
5076a392
FC
2149
2150=head3 L<perlpodstyle>
2151
2152New style guide for POD documentation,
2153split mostly from the NOTES section of the pod2man man page.
2154
41e29def
FC
2155=head3 L<perlsource>, L<perlinterp>, L<perlhacktut>, and L<perlhacktips>
2156
cc13eef1 2157See L</perlhack and perlrepository revamp>, below.
5076a392
FC
2158
2159=head2 Changes to Existing Documentation
2160
41e29def 2161=head3 L<perlmodlib> is now complete
4ed2cea4
FC
2162
2163The perlmodlib page that came with Perl 5.12.0 was missing a lot of
2164modules, due to a bug in the script that generates the list. This has been
cdc10f43 2165fixed [perl #74332] (5.12.1).
4ed2cea4 2166
41e29def 2167=head3 Replace wrong tr/// table in L<perlebcdic>
5076a392 2168
41e29def 2169L<perlebcdic> contains a helpful table to use in tr/// to convert
5076a392
FC
2170between EBCDIC and Latin1/ASCII. Unfortunately, the table was the
2171inverse of the one it describes, though the code that used the table
2172worked correctly for the specific example given.
2173
2174The table has been changed to its inverse, and the sample code changed
2175to correspond, as this is easier for the person trying to follow the
2176instructions since deriving the old table is somewhat more complicated.
2177
2178The table has also been changed to hex from octal, as that is more the norm
2179these days, and the recipes in the pod altered to print out leading
41e29def 2180zeros to make all the values the same length.
5076a392 2181
41e29def 2182=head3 Tricks for user-defined casing
5076a392 2183
41e29def
FC
2184L<perlunicode> now contains an explanation of how to override, mangle
2185and otherwise tweak the way perl handles upper-, lower- and other-case
2186conversions on Unicode data, and how to provide scoped changes to alter
2187one's own code's behaviour without stomping on anybody else.
5076a392
FC
2188
2189=head3 INSTALL explicitly states the requirement for C89
2190
d430b8e7
FC
2191This was already true but it's now Officially Stated For The Record
2192(5.12.2).
5076a392 2193
41e29def 2194=head3 Explanation of C<\xI<HH>> and C<\oI<OOO>> escapes
5076a392 2195
41e29def
FC
2196L<perlop> has been updated with more detailed explanation of these two
2197character escapes.
5076a392 2198
41e29def 2199=head3 C<-0I<NNN>> switch
5076a392 2200
41e29def 2201In L<perlrun>, the behavior of the C<-0NNN> switch for C<-0400> or higher
d430b8e7 2202has been clarified (5.12.2).
5076a392 2203
cdc10f43
FC
2204=head3 Maintenance policy
2205
2206L<perlpolicy> now contains the policy on what patches are acceptable for
2207maintenance branches (5.12.1).
2208
41e29def 2209=head3 Deprecation policy
5076a392 2210
41e29def 2211L<perlpolicy> now contains the policy on compatibility and deprecation
d430b8e7 2212along with definitions of terms like "deprecation" (5.12.2).
5076a392 2213
41e29def 2214=head3 New descriptions in L<perldiag>
5076a392
FC
2215
2216The following existing diagnostics are now documented:
2217
2218=over 4
2219
2220=item *
2221
2222L<Ambiguous use of %c resolved as operator %c|perldiag/"Ambiguous use of %c resolved as operator %c">
2223
2224=item *
2225
2226L<Ambiguous use of %c{%s} resolved to %c%s|perldiag/"Ambiguous use of %c{%s} resolved to %c%s">
2227
2228=item *
2229
2230L<Ambiguous use of %c{%s%s} resolved to %c%s%s|perldiag/"Ambiguous use of %c{%s%s} resolved to %c%s%s">
2231
2232=item *
2233
2234L<Ambiguous use of -%s resolved as -&%s()|perldiag/"Ambiguous use of -%s resolved as -&%s()">
2235
2236=item *
2237
2238L<Invalid strict version format (%s)|perldiag/"Invalid strict version format (%s)">
2239
2240=item *
2241
2242L<Invalid version format (%s)|perldiag/"Invalid version format (%s)">
2243
2244=item *
2245
2246L<Invalid version object|perldiag/"Invalid version object">
2247
2248=back
2249
5076a392
FC
2250=head3 L<perlbook>
2251
41e29def 2252L<perlbook> has been expanded to cover many more popular books.
5076a392 2253
41e29def 2254=head3 C<SvTRUE> macro
5076a392 2255
41e29def
FC
2256The documentation for the C<SvTRUE> macro in
2257L<perlapi> was simply wrong in stating that
5076a392
FC
2258get-magic is not processed. It has been corrected.
2259
41e29def 2260=head3 L<perlvar> revamp
5076a392 2261
41e29def 2262L<perlvar> reorders the variables and groups them by topic. Each variable
5076a392 2263introduced after Perl 5.000 notes the first version in which it is
41e29def 2264available. L<perlvar> also has a new section for deprecated variables to
5076a392
FC
2265note when they were removed.
2266
41e29def 2267=head3 Array and hash slices in scalar context
5076a392 2268
41e29def 2269These are now documented in L<perldata>.
5076a392 2270
41e29def 2271=head3 C<use locale> and formats
5076a392
FC
2272
2273L<perlform> and L<perllocale> have been corrected to state that
2274C<use locale> affects formats.
2275
5076a392
FC
2276=head3 L<overload>
2277
5076a392
FC
2278L<overload>'s documentation has practically undergone a rewrite. It
2279is now much more straightforward and clear.
2280
cc13eef1 2281=head3 perlhack and perlrepository revamp
5076a392
FC
2282
2283The L<perlhack> and perlrepository documents have been heavily edited and
2284split up into several new documents.
2285
2286The L<perlhack> document is now much shorter, and focuses on the Perl 5
2287development process and submitting patches to Perl. The technical content has
2288been moved to several new documents, L<perlsource>, L<perlinterp>,
2289L<perlhacktut>, and L<perlhacktips>. This technical content has only been
2290lightly edited.
2291
2292The perlrepository document has been renamed to L<perlgit>. This new document
2293is just a how-to on using git with the Perl source code. Any other content
2294that used to be in perlrepository has been moved to perlhack.
2295
41e29def 2296=head3 Time::Piece examples
5076a392
FC
2297
2298Examples in L<perlfaq4> have been updated to show the use of
41e29def 2299L<Time::Piece>.
5076a392
FC
2300
2301=head1 Diagnostics
2302
2303The following additions or changes have been made to diagnostic output,
2304including warnings and fatal error messages. For the complete list of
2305diagnostic messages, see L<perldiag>.
2306
2307=head2 New Diagnostics
2308
a593b319
FC
2309=head3 New Errors
2310
5076a392
FC
2311=over
2312
a593b319 2313=item Closure prototype called
5076a392 2314
a593b319
FC
2315This error occurs when a subroutine reference passed to an attribute
2316handler is called, if the subroutine is a closure [perl #68560].
5076a392 2317
a593b319 2318=item Insecure user-defined property %s
5076a392 2319
a593b319
FC
2320Perl detected tainted data when trying to compile a regular
2321expression that contains a call to a user-defined character property
2322function, i.e. C<\p{IsFoo}> or C<\p{InFoo}>.
2323See L<perlunicode/User-Defined Character Properties> and L<perlsec>.
5076a392 2324
a593b319 2325=item panic: gp_free failed to free glob pointer - something is repeatedly re-creating entries
5076a392 2326
a593b319
FC
2327This new error is triggered if a destructor called on an object in a
2328typeglob that is being freed creates a new typeglob entry containing an
2329object with a destructor that creates a new entry containing an object....
5076a392 2330
a593b319 2331=item Parsing code internal error (%s)
5076a392 2332
a593b319
FC
2333This new fatal error is produced when parsing
2334code supplied by an extension violates the
2335parser's API in a detectable way.
5076a392 2336
a593b319 2337=item refcnt: fd %d%s
5076a392 2338
a593b319
FC
2339This new error only occurs if a internal consistency check fails when a
2340pipe is about to be closed.
5076a392 2341
a593b319 2342=item Regexp modifier "/%c" may not appear twice
5076a392 2343
a593b319
FC
2344The regular expression pattern has one of the
2345mutually exclusive modifiers repeated.
5076a392 2346
a593b319 2347=item Regexp modifiers "/%c" and "/%c" are mutually exclusive
5076a392 2348
a593b319
FC
2349The regular expression pattern has more than one of the mutually
2350exclusive modifiers.
5076a392 2351
a593b319 2352=item Using !~ with %s doesn't make sense
5076a392 2353
a593b319 2354This error occurs when C<!~> is used with C<s///r> or C<y///r>.
5076a392 2355
a593b319 2356=back
5076a392 2357
a593b319 2358=head3 New Warnings
5076a392 2359
a593b319 2360=over
5076a392 2361
a593b319 2362=item "\b{" is deprecated; use "\b\{" instead
5076a392 2363
a593b319 2364=item "\B{" is deprecated; use "\B\{" instead
5076a392 2365
a593b319
FC
2366Use of an unescaped "{" immediately following a C<\b> or C<\B> is now
2367deprecated so as to reserve its use for Perl itself in a future release.
5076a392 2368
a593b319 2369=item Operation "%s" returns its argument for ...
5076a392 2370
a593b319
FC
2371Performing an operation requiring Unicode semantics (such as case-folding)
2372on a Unicode surrogate or a non-Unicode character now triggers a warning:
2373'Operation "%s" returns its argument for ...'.
5076a392 2374
a593b319
FC
2375=item Use of qw(...) as parentheses is deprecated
2376
2377See L</"Use of qw(...) as parentheses">, above, for details.
5076a392
FC
2378
2379=back
2380
2381=head2 Changes to Existing Diagnostics
2382
2383=over 4
2384
2385=item *
2386
4ed2cea4
FC
2387The "Variable $foo is not imported" warning that precedes a
2388C<strict 'vars'> error has now been assigned the "misc" category, so that
2389C<no warnings> will suppress it [perl #73712].
2390
2391=item *
2392
5076a392
FC
2393C<warn> and C<die> now produce 'Wide character' warnings when fed a
2394character outside the byte range if STDERR is a byte-sized handle.
2395
2396=item *
2397
2398The 'Layer does not match this perl' error message has been replaced with
a593b319 2399these more helpful messages [perl #73754]:
5076a392
FC
2400
2401=over 4
2402
2403=item *
2404
2405PerlIO layer function table size (%d) does not match size expected by this
2406perl (%d)
2407
2408=item *
2409
2410PerlIO layer instance size (%d) does not match size expected by this perl
2411(%d)
2412
2413=back
2414
5076a392
FC
2415=item *
2416
2417The "Found = in conditional" warning that is emitted when a constant is
2418assigned to a variable in a condition is now withheld if the constant is
2419actually a subroutine or one generated by C<use constant>, since the value
2420of the constant may not be known at the time the program is written
2421[perl #77762].
2422
2423=item *
2424
2425Previously, if none of the C<gethostbyaddr>, C<gethostbyname> and
2426C<gethostent> functions were implemented on a given platform, they would
2427all die with the message 'Unsupported socket function "gethostent" called',
2428with analogous messages for C<getnet*> and C<getserv*>. This has been
2429corrected.
2430
2431=item *
2432
a593b319
FC
2433The warning message about unrecognized regular expression escapes passed
2434through has been changed to include any literal '{' following the
2435two-character escape. E.g., "\q{" is now emitted instead of "\q".
5076a392
FC
2436
2437=back
2438
2439=head1 Utility Changes
2440
0b88cc74 2441=head3 L<perlbug>
5076a392
FC
2442
2443=over 4
2444
2445=item *
2446
0b88cc74
FC
2447L<perlbug> now looks in the EMAIL environment variable for a return address
2448if the REPLY-TO and REPLYTO variables are empty.
5076a392
FC
2449
2450=item *
2451
0b88cc74
FC
2452L<perlbug> did not previously generate a From: header, potentially
2453resulting in dropped mail. Now it does include that header.
5076a392
FC
2454
2455=item *
2456
0b88cc74 2457The user's address is now used as the return-path.
4ed2cea4 2458
0b88cc74
FC
2459Many systems these days don't have a valid Internet domain name and
2460perlbug@perl.org does not accept email with a return-path that does
2461not resolve. So the user's address is now passed to sendmail so it's
2462less likely to get stuck in a mail queue somewhere [perl #82996].
5076a392 2463
2c389f6c
FC
2464=item *
2465
d430b8e7
FC
2466L<perlbug> now always gives the reporter a chance to change the email
2467address it guesses for them (5.12.2).
2468
2469=item *
2470
2471L<perlbug> should no longer warn about uninitialized values when using the C<-d>
2472and C<-v> options (5.12.2).
2c389f6c 2473
5076a392
FC
2474=back
2475
0b88cc74 2476=head3 L<perl5db.pl>
5076a392 2477
0b88cc74 2478=over
5076a392
FC
2479
2480=item *
2481
0b88cc74
FC
2482The remote terminal works after forking and spawns new sessions - one
2483for each forked process.
5076a392
FC
2484
2485=back
2486
0b88cc74 2487=head3 L<ptargrep>
5076a392
FC
2488
2489=over 4
2490
2491=item *
2492
0b88cc74
FC
2493L<ptargrep> is a new utility to apply pattern matching to the contents of
2494files in a tar archive. It comes with C<Archive::Tar>.
5076a392
FC
2495
2496=back
2497
2498=head1 Configuration and Compilation
2499
61752d82
FC
2500See also L</"Naming fixes in Policy_sh.SH may invalidate Policy.sh">,
2501above.
2502
5076a392
FC
2503=over 4
2504
2505=item *
2506
87595b22
FC
2507CCINCDIR and CCLIBDIR for the mingw64
2508cross-compiler are now correctly under
5076a392
FC
2509$(CCHOME)\mingw\include and \lib rather than immediately below $(CCHOME).
2510
5076a392
FC
2511This means the 'incpath', 'libpth', 'ldflags', 'lddlflags' and
2512'ldflags_nolargefiles' values in Config.pm and Config_heavy.pl are now
87595b22 2513set correctly.
5076a392
FC
2514
2515=item *
2516
87595b22
FC
2517'make test.valgrind' has been adjusted to account for cpan/dist/ext
2518separation.
5076a392
FC
2519
2520=item *
2521
2522On compilers that support it, C<-Wwrite-strings> is now added to cflags by
2523default.
2524
2525=item *
2526
2527The C<Encode> module can now (once again) be included in a static Perl
2528build. The special-case handling for this situation got broken in Perl
25295.11.0, and has now been repaired.
2530
1e463951
FC
2531=item *
2532
2533The previous default size of a PerlIO buffer (4096 bytes) has been increased
2534to the larger of 8192 bytes and your local BUFSIZ. Benchmarks show that doubling
2535this decade-old default increases read and write performance in the neighborhood
2536of 25% to 50% when using the default layers of perlio on top of unix. To choose
2537a non-default size, such as to get back the old value or to obtain an even
2538larger value, configure with:
2539
2540 ./Configure -Accflags=-DPERLIOBUF_DEFAULT_BUFSIZ=N
2541
2542where N is the desired size in bytes; it should probably be a multiple of
2543your page size.
2544
d430b8e7
FC
2545=item *
2546
2547An "incompatible operand types" error in ternary expressions when building
2548with C<clang> has been fixed (5.12.2).
2549
2550=item *
2551
2552Perl now skips setuid C<File::Copy> tests on partitions it detects to be mounted
2553as C<nosuid> (5.12.2).
2554
5076a392
FC
2555=back
2556
5076a392
FC
2557=head1 Platform Support
2558
5076a392
FC
2559=head2 New Platforms
2560
5076a392
FC
2561=over 4
2562
2563=item AIX
2564
cdc10f43 2565Perl now builds on AIX 4.2 (5.12.1).
5076a392
FC
2566
2567=back
2568
2569=head2 Discontinued Platforms
2570
2571=over 4
2572
5076a392
FC
2573=item Apollo DomainOS
2574
2575The last vestiges of support for this platform have been excised from the
2576Perl distribution. It was officially discontinued in version 5.12.0. It had
2577not worked for years before that.
2578
2579=item MacOS Classic
2580
2581The last vestiges of support for this platform have been excised from the
2582Perl distribution. It was officially discontinued in an earlier version.
2583
2584=back
2585
2586=head2 Platform-Specific Notes
2587
d430b8e7
FC
2588=head3 AIX
2589
2590=over
2591
2592=item *
2593
2594F<README.aix> has been updated with information about the XL C/C++ V11 compiler
2595suite (5.12.2).
2596
2597=back
2598
2599=head3 ARM
2600
2601=over
2602
2603=item *
2604
2605The C<d_u32align> configuration probe on ARM has been fixed (5.12.2).
2606
2607=back
2608
554003a2 2609=head3 Cygwin
5076a392
FC
2610
2611=over 4
2612
2613=item *
2614
554003a2 2615MakeMaker has been updated to build man pages on cygwin.
5076a392
FC
2616
2617=item *
2618
554003a2
FC
2619Improved rebase behaviour
2620
2621If a dll is updated on cygwin the old imagebase address is reused.
2622This solves most rebase errors, especially when updating on core dll's.
2623See L<http://www.tishler.net/jason/software/rebase/rebase-2.4.2.README> for more information.
5076a392
FC
2624
2625=item *
2626
554003a2 2627Support for the standard cygwin dll prefix, which is e.g. needed for FFI's
5076a392
FC
2628
2629=item *
2630
554003a2 2631Updated build hints file
5076a392
FC
2632
2633=back
2634
cdc10f43
FC
2635=head3 FreeBSD 7
2636
2637=over
2638
2639=item *
2640
2641FreeBSD 7 no longer contains F</usr/bin/objformat>. At build time,
2642Perl now skips the F<objformat> check for versions 7 and higher and
2643assumes ELF (5.12.1).
2644
2645=back
2646
2647=head3 HP-UX
2648
2649=over
2650
2651=item *
2652
2653Perl now allows -Duse64bitint without promoting to use64bitall on HP-UX
2654(5.12.1).
2655
2656=back
2657
554003a2 2658=head3 IRIX
5076a392
FC
2659
2660Conversion of strings to floating-point numbers is now more accurate on
2661IRIX systems [perl #32380].
2662
554003a2 2663=head3 Mac OS X
5076a392
FC
2664
2665Early versions of Mac OS X (Darwin) had buggy implementations of the
2666C<setregid>, C<setreuid>, C<setrgid> and C<setruid> functions, so perl
2667would pretend they did not exist.
2668
2669These functions are now recognised on Mac OS 10.5 (Leopard; Darwin 9) and
2670higher, as they have been fixed [perl #72990].
2671
554003a2 2672=head3 MirBSD
5076a392 2673
554003a2
FC
2674Previously if you built perl with a shared libperl.so on MirBSD (the
2675default config), it would work up to the installation; however, once
2676installed, it would be unable to find libperl. So path handling is now
2677treated as in the other BSD dialects.
5076a392 2678
554003a2 2679=head3 NetBSD
5076a392 2680
554003a2
FC
2681The NetBSD hints file has been changed to make the system's malloc the
2682default.
5076a392 2683
554003a2 2684=head3 Recent OpenBSDs now use perl's malloc
5076a392 2685
554003a2
FC
2686OpenBSD E<gt> 3.7 has a new malloc implementation which is mmap-based
2687and as such can release memory back to the OS; however, perl's use of
2688this malloc causes a substantial slowdown so we now default to using
2689perl's malloc instead [perl #75742].
5076a392 2690
554003a2 2691=head3 OpenVOS
5076a392 2692
554003a2 2693perl now builds again with OpenVOS (formerly known as Stratus VOS)
5a553547 2694[perl #78132] (5.12.3).
5076a392 2695
554003a2 2696=head3 Solaris
5076a392 2697
554003a2 2698DTrace is now supported on Solaris. There used to be build failures, but
5a553547 2699these have been fixed [perl #73630] (5.12.3).
5076a392 2700
554003a2 2701=head3 VMS
5076a392
FC
2702
2703=over
2704
2705=item *
2706
cdc10f43
FC
2707It's now possible to build extensions on older (pre 7.3-2) VMS systems.
2708
2709DCL symbol length was limited to 1K up until about seven years or
2710so ago, but there was no particularly deep reason to prevent those
2711older systems from configuring and building Perl (5.12.1).
2712
2713=item *
2714
2715We fixed the previously-broken C<-Uuseperlio> build on VMS.
2716
2717We were checking a variable that doesn't exist in the non-default
2718case of disabling perlio. Now we only look at it when it exists (5.12.1).
2719
2720=item *
2721
2722We fixed the -Uuseperlio command-line option in configure.com.
2723
2724Formerly it only worked if you went through all the questions
2725interactively and explicitly answered no (5.12.1).
2726
2727=item *
2728
554003a2 2729C<PerlIOUnix_open> now honours the default permissions on VMS.
5076a392 2730
554003a2
FC
2731When C<perlio> became the default and C<unixio> became the default bottom layer,
2732the most common path for creating files from Perl became C<PerlIOUnix_open>,
2733which has always explicitly used C<0666> as the permission mask.
5076a392 2734
554003a2
FC
2735To avoid this, C<0777> is now passed as the permissions to C<open()>. In the
2736VMS CRTL, C<0777> has a special meaning over and above intersecting with the
2737current umask; specifically, it allows Unix syscalls to preserve native default
5a553547
FC
2738permissions (5.12.3).
2739
2740=item *
2741
2742Spurious record boundaries are no longer
2743introduced by the PerlIO layer during output (5.12.3).
5076a392
FC
2744
2745=item *
2746
554003a2
FC
2747The shortening of symbols longer than 31 characters in the C sources is
2748now done by the compiler rather than by xsubpp (which could only do so
2749for generated symbols in XS code).
5076a392
FC
2750
2751=item *
2752
554003a2
FC
2753Record-oriented files (record format variable or variable with fixed control)
2754opened for write by the perlio layer will now be line-buffered to prevent the
2755introduction of spurious line breaks whenever the perlio buffer fills up.
5076a392 2756
d430b8e7
FC
2757=item *
2758
2759F<git_version.h> is now installed on VMS. This was an oversight in v5.12.0 which
2760caused some extensions to fail to build (5.12.2).
2761
2762=item *
2763
2764Several memory leaks in L<stat()|perlfunc/"stat FILEHANDLE"> have been fixed (5.12.2).
2765
2766=item *
2767
2768A memory leak in C<Perl_rename()> due to a double allocation has been
2769fixed (5.12.2).
2770
2771=item *
2772
2773A memory leak in C<vms_fid_to_name()> (used by C<realpath()> and
2774C<realname()>) has been fixed (5.12.2).
2775
5076a392
FC
2776=back
2777
554003a2 2778=head3 Windows
5076a392 2779
5a1f7719
FC
2780See also L</"fork() emulation will not wait for signalled children"> and
2781L</"Perl source code is read in text mode on Windows">, above.
2782
5076a392
FC
2783=over 4
2784
2785=item *
2786
554003a2 2787Fixed build process for SDK2003SP1 compilers.
5076a392 2788
554003a2 2789=item *
5076a392 2790
01b1a9e4
FC
2791Compilation with Visual Studio 2010 is now supported.
2792
2793=item *
2794
554003a2
FC
2795When using old 32-bit compilers, the define C<_USE_32BIT_TIME_T> will now
2796be set in C<$Config{ccflags}>. This improves portability when compiling
2797XS extensions using new compilers, but for a perl compiled with old 32-bit
2798compilers.
5076a392
FC
2799
2800=item *
2801
554003a2
FC
2802C<$Config{gccversion}> is now set correctly when perl is built using the
2803mingw64 compiler from L<http://mingw64.org> [perl #73754].
5076a392 2804
554003a2
FC
2805=item *
2806
d430b8e7
FC
2807When building Perl with the mingw64 x64 cross-compiler C<incpath>,
2808C<libpth>, C<ldflags>, C<lddlflags> and C<ldflags_nolargefiles> values
2809in F<Config.pm> and F<Config_heavy.pl> were not previously being set
2810correctly because, with that compiler, the include and lib directories
2811are not immediately below C<$(CCHOME)> (5.12.2).
2812
2813=item *
2814
554003a2
FC
2815The build process proceeds more smoothly with mingw and dmake when
2816F<C:\MSYS\bin> is in the PATH, due to a C<Cwd> fix.
5076a392
FC
2817
2818=item *
2819
554003a2
FC
2820Support for building with Visual C++ 2010 is now underway, but is not yet
2821complete. See F<README.win32> or L<perlwin32> for more details.
5076a392 2822
554003a2
FC
2823=item *
2824
2825The option to use an externally-supplied C<crypt()>, or to build with no
2826C<crypt()> at all, has been removed. Perl supplies its own C<crypt()>
2827implementation for Windows, and the political situation that required
2828this part of the distribution to sometimes be omitted is long gone.
5076a392
FC
2829
2830=back
2831
2832=head1 Internal Changes
2833
1e463951 2834=head2 New APIs
5076a392 2835
1e463951 2836=head3 CLONE_PARAMS structure added to ease correct thread creation
5076a392 2837
1e463951
FC
2838Modules that create threads should now create C<CLONE_PARAMS> structures
2839by calling the new function C<Perl_clone_params_new()>, and free them with
2840C<Perl_clone_params_del()>. This will ensure compatibility with any future
2841changes to the internals of the C<CLONE_PARAMS> structure layout, and that
2842it is correctly allocated and initialised.
5076a392 2843
1e463951 2844=head3 New parsing functions
5076a392 2845
1e463951
FC
2846Several functions have been added for parsing statements or multiple
2847statements:
5076a392 2848
1e463951 2849=over
5076a392
FC
2850
2851=item *
2852
1e463951 2853C<parse_fullstmt> parses a complete Perl statement.
5076a392
FC
2854
2855=item *
2856
1e463951
FC
2857C<parse_stmtseq> parses a sequence of statements, up
2858to closing brace or EOF.
5076a392
FC
2859
2860=item *
2861
1e463951 2862C<parse_block> parses a block [perl #78222].
5076a392
FC
2863
2864=item *
2865
1e463951
FC
2866C<parse_barestmt> parses a statement
2867without a label.
5076a392
FC
2868
2869=item *
2870
1e463951 2871C<parse_label> parses a statement label, separate from statements.
5076a392 2872
1e463951 2873=back
5076a392 2874
1e463951
FC
2875The
2876L<C<parse_fullexpr()>|perlapi/parse_fullexpr>,
2877L<C<parse_listexpr()>|perlapi/parse_listexpr>,
2878L<C<parse_termexpr()>|perlapi/parse_termexpr>, and
2879L<C<parse_arithexpr()>|perlapi/parse_arithexpr>
2880functions have been added to the API. They perform
2881recursive-descent parsing of expressions at various precedence levels.
2882They are expected to be used by syntax plugins.
5076a392 2883
1e463951 2884See L<perlapi> for details.
5076a392 2885
1e463951 2886=head3 Hints hash API
5076a392 2887
1e463951
FC
2888A new C API for introspecting the hinthash C<%^H> at runtime has been
2889added. See C<cop_hints_2hv>, C<cop_hints_fetchpvn>, C<cop_hints_fetchpvs>,
2890C<cop_hints_fetchsv>, and C<hv_copy_hints_hv> in L<perlapi> for details.
5076a392 2891
1e463951
FC
2892A new, experimental API has been added for accessing the internal
2893structure that Perl uses for C<%^H>. See the functions beginning with
2894C<cophh_> in L<perlapi>.
5076a392 2895
1e463951 2896=head3 C interface to C<caller()>
5076a392 2897
1e463951
FC
2898The C<caller_cx> function has been added as an XSUB-writer's equivalent of
2899C<caller()>. See L<perlapi> for details.
5076a392 2900
1e463951 2901=head3 Custom per-subroutine check hooks
5076a392 2902
1e463951
FC
2903XS code in an extension module can now annotate a subroutine (whether
2904implemented in XS or in Perl) so that nominated XS code will be called
2905at compile time (specifically as part of op checking) to change the op
2906tree of that subroutine. The compile-time check function (supplied by
2907the extension module) can implement argument processing that can't be
2908expressed as a prototype, generate customised compile-time warnings,
2909perform constant folding for a pure function, inline a subroutine
2910consisting of sufficiently simple ops, replace the whole call with a
2911custom op, and so on. This was previously all possible by hooking the
2912C<entersub> op checker, but the new mechanism makes it easy to tie the
2913hook to a specific subroutine. See L<perlapi/cv_set_call_checker>.
5076a392 2914
1e463951
FC
2915To help in writing custom check hooks, several subtasks within standard
2916C<entersub> op checking have been separated out and exposed in the API.
5076a392 2917
1e463951 2918=head3 Improved support for custom OPs
5076a392 2919
1e463951
FC
2920Custom ops can now be registered with the new C<custom_op_register> C
2921function and the C<XOP> structure. This will make it easier to add new
2922properties of custom ops in the future. Two new properties have been added
2923already, C<xop_class> and C<xop_peep>.
5076a392 2924
1e463951
FC
2925C<xop_class> is one of the OA_*OP constants, and allows L<B> and other
2926introspection mechanisms to work with custom ops
2927that aren't BASEOPs. C<xop_peep> is a pointer to
2928a function that will be called for ops of this
2929type from C<Perl_rpeep>.
5076a392 2930
1e463951
FC
2931See L<perlguts/Custom Operators> and L<perlapi/Custom Operators> for more
2932detail.
5076a392 2933
1e463951
FC
2934The old C<PL_custom_op_names>/C<PL_custom_op_descs> interface is still
2935supported but discouraged.
5076a392 2936
1e463951 2937=head3 Scope hooks
5076a392 2938
1e463951
FC
2939It is now possible for XS code to hook into Perl's lexical scope
2940mechanism at compile time, using the new C<Perl_blockhook_register>
2941function. See L<perlguts/"Compile-time scope hooks">.
5076a392 2942
1e463951 2943=head3 The recursive part of the peephole optimizer is now hookable
5076a392
FC
2944
2945In addition to C<PL_peepp>, for hooking into the toplevel peephole optimizer, a
2946C<PL_rpeepp> is now available to hook into the optimizer recursing into
2947side-chains of the optree.
2948
1e463951 2949=head3 New non-magical variants of existing functions
5076a392 2950
1e463951
FC
2951The following functions/macros have been added to the API. The C<*_nomg>
2952macros are equivalent to their non-_nomg variants, except that they ignore
2953get-magic. Those ending in C<_flags> allow one to specify whether
2954get-magic is processed.
5076a392 2955
1e463951
FC
2956 sv_2bool_flags
2957 SvTRUE_nomg
2958 sv_2nv_flags
2959 SvNV_nomg
2960 sv_cmp_flags
2961 sv_cmp_locale_flags
2962 sv_eq_flags
2963 sv_collxfrm_flags
5076a392 2964
1e463951 2965In some of these cases, the non-_flags functions have
5076a392
FC
2966been replaced with wrappers around the new functions.
2967
1e463951 2968=head3 pv/pvs/sv versions of existing functions
5076a392 2969
1e463951 2970Many functions ending with pvn now have equivalent pv/pvs/sv versions.
5076a392 2971
1e463951 2972=head3 List op-building functions
5076a392 2973
1e463951
FC
2974List op-building functions have been added to the
2975API. See L<op_append_elem|perlapi/op_append_elem>,
2976L<op_append_list|perlapi/op_append_list>, and
2977L<op_prepend_elem|perlapi/op_prepend_elem> in L<perlapi>.
5076a392 2978
1e463951 2979=head3 C<LINKLIST>
5076a392 2980
1e463951
FC
2981The L<LINKLIST|perlapi/LINKLIST> macro, part of op building that
2982constructs the execution-order op chain, has been added to the API.
5076a392 2983
1e463951 2984=head3 Localisation functions
5076a392 2985
1e463951
FC
2986The C<save_freeop>, C<save_op>, C<save_pushi32ptr> and C<save_pushptrptr>
2987functions have been added to the API.
5076a392 2988
1e463951 2989=head3 Stash names
5076a392 2990
1e463951
FC
2991A stash can now have a list of effective names in addition to its usual
2992name. The first effective name can be accessed via the C<HvENAME> macro,
2993which is now the recommended name to use in MRO linearisations (C<HvNAME>
2994being a fallback if there is no C<HvENAME>).
5076a392 2995
1e463951
FC
2996These names are added and deleted via C<hv_ename_add> and
2997C<hv_ename_delete>. These two functions are I<not> part of the API.
5076a392 2998
1e463951 2999=head3 New functions for finding and removing magic
5076a392 3000
1e463951
FC
3001The L<C<mg_findext()>|perlapi/mg_findext> and
3002L<C<sv_unmagicext()>|perlapi/sv_unmagicext>
3003functions have been added to the API.
3004They allow extension authors to find and remove magic attached to
3005scalars based on both the magic type and the magic virtual table, similar to how
3006C<sv_magicext()> attaches magic of a certain type and with a given virtual table
3007to a scalar. This eliminates the need for extensions to walk the list of
3008C<MAGIC> pointers of an C<SV> to find the magic that belongs to them.
5076a392 3009
1e463951 3010=head3 C<find_rundefsv>
5076a392 3011
1e463951
FC
3012This function returns the SV representing C<$_>, whether it's lexical
3013or dynamic.
5076a392 3014
1e463951 3015=head3 C<Perl_croak_no_modify>
5076a392 3016
1e463951
FC
3017C<Perl_croak_no_modify()> is short-hand for
3018C<Perl_croak("%s", PL_no_modify)>.
5076a392 3019
1e463951 3020=head3 C<PERL_STATIC_INLINE> define
5076a392 3021
1e463951
FC
3022The C<PERL_STATIC_INLINE> define has been added to provide the best-guess
3023incantation to use for static inline functions, if the C compiler supports
3024C99-style static inline. If it doesn't, it'll give a plain C<static>.
5076a392 3025
1e463951
FC
3026C<HAS_STATIC_INLINE> can be used to check if the compiler actually supports
3027inline functions.
5076a392 3028
1e463951 3029=head3 New C<pv_escape> option for hexadecimal escapes
5076a392 3030
1e463951
FC
3031A new option, C<PERL_PV_ESCAPE_NONASCII>, has been added to C<pv_escape> to
3032dump all characters above ASCII in hexadecimal. Before, one could get all
3033characters as hexadecimal or the Latin1 non-ASCII as octal.
5076a392 3034
1e463951 3035=head3 C<lex_start>
5076a392 3036
1e463951 3037C<lex_start> has been added to the API, but is considered experimental.
5076a392 3038
1e463951 3039=head3 C<op_scope()> and C<op_lvalue()>
5076a392 3040
1e463951
FC
3041The C<op_scope()> and C<op_lvalue()> functions have been added to the API,
3042but are considered experimental.
5076a392 3043
1e463951 3044=head2 C API Changes
5076a392 3045
1e463951 3046=head3 C<PERL_POLLUTE> has been removed
5076a392 3047
1e463951
FC
3048The option to define C<PERL_POLLUTE> to expose older 5.005 symbols for
3049backwards compatibility has been removed. It's use was always discouraged,
3050and MakeMaker contains a more specific escape hatch:
5076a392 3051
1e463951 3052 perl Makefile.PL POLLUTE=1
5076a392 3053
1e463951
FC
3054This can be used for modules that have not been upgraded to 5.6 naming
3055conventions (and really should be completely obsolete by now).
5076a392 3056
1e463951 3057=head3 Check API compatibility when loading XS modules
5076a392 3058
1e463951
FC
3059When perl's API changes in incompatible ways (which usually happens between
3060major releases), XS modules compiled for previous versions of perl will not
3061work anymore. They will need to be recompiled against the new perl.
5076a392 3062
1e463951
FC
3063In order to ensure that modules are recompiled, and to prevent users from
3064accidentally loading modules compiled for old perls into newer ones, the
3065C<XS_APIVERSION_BOOTCHECK> macro has been added. That macro, which is
3066called when loading every newly compiled extension, compares the API
3067version of the running perl with the version a module has been compiled for
3068and raises an exception if they don't match.
5076a392 3069
1e463951 3070=head3 Perl_fetch_cop_label
5076a392 3071
1e463951
FC
3072The first argument of the C API function C<Perl_fetch_cop_label> has changed
3073from C<struct refcounted he *> to C<COP *>, to insulate the user from
3074implementation details.
5076a392 3075
1e463951
FC
3076This API function was marked as "may change", and likely isn't in use outside
3077the core. (Neither an unpacked CPAN, nor Google's codesearch, finds any other
3078references to it.)
5076a392 3079
1e463951 3080=head3 GvCV() and GvGP() are no longer lvalues
5076a392 3081
1e463951
FC
3082The new GvCV_set() and GvGP_set() macros are now provided to replace
3083assignment to those two macros.
5076a392 3084
1e463951
FC
3085This allows a future commit to eliminate some backref magic between GV
3086and CVs, which will require complete control over assignment to the
3087gp_cv slot.
5076a392 3088
1e463951 3089=head3 CvGV() is no longer an lvalue
5076a392 3090
1e463951
FC
3091Under some circumstances, the C<CvGV()> field of a CV is now
3092reference-counted. To ensure consistent behaviour, direct assignment to
3093it, for example C<CvGV(cv) = gv> is now a compile-time error. A new macro,
3094C<CvGV_set(cv,gv)> has been introduced to perform this operation
3095safely. Note that modification of this field is not part of the public
3096API, regardless of this new macro (and despite its being listed in this section).
5076a392 3097
1e463951 3098=head3 CvSTASH() is no longer an lvalue
5076a392 3099
1e463951
FC
3100The C<CvSTASH()> macro can now only be used as an rvalue. C<CvSTASH_set()>
3101has been added to replace assignment to C<CvSTASH()>. This is to ensure
3102that backreferences are handled properly. These macros are not part of the
3103API.
5076a392 3104
1e463951 3105=head3 Calling conventions for C<newFOROP> and C<newWHILEOP>
5076a392 3106
1e463951
FC
3107The way the parser handles labels has been cleaned up and refactored. As a
3108result, the C<newFOROP()> constructor function no longer takes a parameter
3109stating what label is to go in the state op.
5076a392 3110
1e463951
FC
3111The C<newWHILEOP()> and C<newFOROP()> functions no longer accept a line
3112number as a parameter.
5076a392 3113
1e463951 3114=head3 Flags passed to C<uvuni_to_utf8_flags> and C<utf8n_to_uvuni>
5076a392 3115
1e463951
FC
3116Some of the flags parameters to uvuni_to_utf8_flags() and
3117utf8n_to_uvuni() have changed. This is a result of Perl's now allowing
5076a392
FC
3118internal storage and manipulation of code points that are problematic
3119in some situations. Hence, the default actions for these functions has
3120been complemented to allow these code points. The new flags are
3121documented in L<perlapi>. Code that requires the problematic code
483b16f3 3122points to be rejected needs to change to use the new flags. Some flag
5076a392
FC
3123names are retained for backward source compatibility, though they do
3124nothing, as they are now the default. However the flags
3125C<UNICODE_ALLOW_FDD0>, C<UNICODE_ALLOW_FFFF>, C<UNICODE_ILLEGAL>, and
3126C<UNICODE_IS_ILLEGAL> have been removed, as they stem from a
3127fundamentally broken model of how the Unicode non-character code points
3128should be handled, which is now described in
3129L<perlunicode/Non-character code points>. See also L</Selected Bug Fixes>.
3130
1e463951 3131XXX Which bugs in particular? Selected Bug Fixes is too long for this link
483b16f3
KW
3132to be meaningful right now
3133I don't see the bugs in that section currently -- khw
5076a392 3134
1e463951 3135=head2 Deprecated C APIs
5076a392 3136
1e463951 3137=over
5076a392 3138
1e463951 3139=item C<Perl_ptr_table_clear>
5076a392 3140
1e463951
FC
3141C<Perl_ptr_table_clear> is no longer part of Perl's public API. Calling it
3142now generates a deprecation warning, and it will be removed in a future
3143release.
5076a392 3144
1e463951 3145=item C<sv_compile_2op>
5076a392 3146
1e463951
FC
3147The C<sv_compile_2op()> API function is now deprecated. Searches suggest
3148that nothing on CPAN is using it, so this should have zero impact.
5076a392 3149
1e463951
FC
3150It attempted to provide an API to compile code down to an optree, but failed
3151to bind correctly to lexicals in the enclosing scope. It's not possible to
3152fix this problem within the constraints of its parameters and return value.
5076a392 3153
1e463951 3154=item C<find_rundefsvoffset>
5076a392 3155
1e463951
FC
3156The C<find_rundefsvoffset> function has been deprecated. It appeared that
3157its design was insufficient for reliably getting the lexical C<$_> at
3158run-time.
5076a392 3159
1e463951
FC
3160Use the new C<find_rundefsv> function or the C<UNDERBAR> macro
3161instead. They directly return the right SV representing C<$_>, whether it's
3162lexical or dynamic.
5076a392 3163
1e463951 3164=item C<CALL_FPTR> and C<CPERLscope>
5076a392 3165
1e463951
FC
3166Those are left from an old implementation of C<MULTIPLICITY> using C++ objects,
3167which was removed in Perl 5.8. Nowadays these macros do exactly nothing, so
3168they shouldn't be used anymore.
5076a392 3169
1e463951
FC
3170For compatibility, they are still defined for external C<XS> code. Only
3171extensions defining C<PERL_CORE> must be updated now.
5076a392 3172
1e463951 3173=back
5076a392 3174
1e463951 3175=head2 Other Internal Changes
5076a392 3176
1e463951 3177=head3 Stack unwinding
5076a392 3178
1e463951
FC
3179The protocol for unwinding the C stack at the last stage of a C<die>
3180has changed how it identifies the target stack frame. This now uses
3181a separate variable C<PL_restartjmpenv>, where previously it relied on
3182the C<blk_eval.cur_top_env> pointer in the C<eval> context frame that
3183has nominally just been discarded. This change means that code running
3184during various stages of Perl-level unwinding no longer needs to take
3185care to avoid destroying the ghost frame.
5076a392 3186
1e463951 3187=head3 Scope stack entries
5076a392 3188
1e463951
FC
3189The format of entries on the scope stack has been changed, resulting in a
3190reduction of memory usage of about 10%. In particular, the memory used by
3191the scope stack to record each active lexical variable has been halved.
5076a392 3192
1e463951 3193=head3 Memory allocation for pointer tables
5076a392 3194
1e463951
FC
3195Memory allocation for pointer tables has been changed. Previously
3196C<Perl_ptr_table_store> allocated memory from the same arena system as
3197C<SV> bodies and C<HE>s, with freed memory remaining bound to those arenas
3198until interpreter exit. Now it allocates memory from arenas private to the
3199specific pointer table, and that memory is returned to the system when
3200C<Perl_ptr_table_free> is called. Additionally, allocation and release are
3201both less CPU intensive.
5076a392 3202
1e463951 3203=head3 C<UNDERBAR>
5076a392 3204
1e463951
FC
3205The C<UNDERBAR> macro now calls C<find_rundefsv>. C<dUNDERBAR> is now a
3206noop but should still be used to ensure past and future compatibility.
5076a392 3207
1e463951 3208=head3 String comparison routines renamed
5076a392 3209
1e463951
FC
3210The ibcmp_* functions have been renamed and are now called foldEQ,
3211foldEQ_locale and foldEQ_utf8. The old names are still available as
3212macros.
3213
3214=head3 C<chop> and C<chomp> implementations merged
3215
3216The opcode bodies for C<chop> and C<chomp> and for C<schop> and C<schomp>
3217have been merged. The implementation functions C<Perl_do_chop()> and
3218C<Perl_do_chomp()>, never part of the public API, have been merged and
3219moved to a static function in F<pp.c>. This shrinks the perl binary
3220slightly, and should not affect any code outside the core (unless it is
3221relying on the order of side effects when C<chomp> is passed a I<list> of
3222values).
5076a392
FC
3223
3224=head1 Selected Bug Fixes
3225
e8e35311
FC
3226=head2 I/O
3227
5076a392
FC
3228=over 4
3229
3230=item *
3231
e8e35311 3232Perl no longer produces this warning:
a593b319
FC
3233
3234 $ perl -we 'open my $f, ">", \my $x; binmode $f, "scalar"'
3235 Use of uninitialized value in binmode at -e line 1.
3236
3237=item *
3238
e8e35311
FC
3239Opening a glob reference via C<< open $fh, "E<gt>", \*glob >> will no longer
3240cause the glob to be corrupted when the filehandle is printed to. This would
3241cause perl to crash whenever the glob's contents were accessed
3242[perl #77492].
4ed2cea4
FC
3243
3244=item *
3245
e8e35311
FC
3246PerlIO no longer crashes when called recursively, e.g., from a signal
3247handler. Now it just leaks memory [perl #75556].
4ed2cea4
FC
3248
3249=item *
3250
e8e35311
FC
3251Most I/O functions were not warning for unopened handles unless the
3252'closed' and 'unopened' warnings categories were both enabled. Now only
3253C<use warnings 'unopened'> is necessary to trigger these warnings (as was
438c239f 3254always meant to be the case).
4ed2cea4
FC
3255
3256=item *
3257
438c239f 3258There have been several fixes to PerlIO layers:
e8e35311 3259
438c239f
FC
3260When C<binmode FH, ":crlf"> pushes the C<:crlf> layer on top of the stack,
3261it no longer enables crlf layers lower in the stack, to avoid unexpected
3262results [perl #38456].
4ed2cea4 3263
438c239f
FC
3264Opening a file in C<:raw> mode now does what it advertises to do (first
3265open the file, then binmode it), instead of simply leaving off the top
3266layer [perl #80764].
5076a392 3267
438c239f
FC
3268The three layers C<:pop>, C<:utf8> and C<:bytes> didn't allow stacking when
3269opening a file. For example
e8e35311 3270this:
5076a392 3271
e8e35311 3272 open FH, '>:pop:perlio', 'some.file' or die $!;
5076a392 3273
438c239f
FC
3274Would throw an error: "Invalid argument". This has been fixed in this
3275release [perl #82484].
5076a392 3276
e8e35311
FC
3277=back
3278
3279=head2 Regular Expression Bug Fixes
3280
3281=over
5076a392
FC
3282
3283=item *
3284
e8e35311
FC
3285The regular expression engine no longer loops when matching
3286C<"\N{LATIN SMALL LIGATURE FF}" =~ /f+/i> and similar expressions
cdc10f43 3287[perl #72998] (5.12.1).
5076a392
FC
3288
3289=item *
3290
e8e35311
FC
3291The trie runtime code should no longer allocate massive amounts of memory,
3292fixing #74484.
5076a392
FC
3293
3294=item *
3295
438c239f
FC
3296Syntax errors in C<< (?{...}) >> blocks no longer cause panic messages
3297[perl #2353].
5076a392
FC
3298
3299=item *
3300
438c239f
FC
3301A pattern like C<(?:(o){2})?> no longer causes a "panic" error
3302[perl #39233].
5076a392
FC
3303
3304=item *
3305
438c239f 3306A fatal error in regular expressions containing C<(.*?)> when processing
d430b8e7 3307UTF-8 data has been fixed [perl #75680] (5.12.2).
5076a392
FC
3308
3309=item *
3310
e8e35311 3311An erroneous regular expression engine optimisation that caused regex verbs like
438c239f 3312C<*COMMIT> sometimes to be ignored has been removed.
5076a392
FC
3313
3314=item *
3315
e8e35311
FC
3316The regular expression bracketed character class C<[\8\9]> was effectively the
3317same as C<[89\000]>, incorrectly matching a NULL character. It also gave
3318incorrect warnings that the C<8> and C<9> were ignored. Now C<[\8\9]> is the
3319same as C<[89]> and gives legitimate warnings that C<\8> and C<\9> are
3320unrecognized escape sequences, passed-through.
5076a392
FC
3321
3322=item *
3323
e8e35311
FC
3324A regular expression match in the right-hand side of a global substitution
3325(C<s///g>) that is in the same scope will no longer cause match variables
3326to have the wrong values on subsequent iterations. This can happen when an
3327array or hash subscript is interpolated in the right-hand side, as in
3328C<s|(.)|@a{ print($1), /./ }|g> [perl #19078].
5076a392
FC
3329
3330=item *
3331
438c239f
FC
3332Several cases in which characters in the Latin-1 non-ASCII range (0x80 to
33330xFF) used not to match themselves or used to match both a character class
3334and its complement have been fixed. For instance, U+00E2 could match both
3335C<\w> and C<\W> [perl #78464] [perl #18281] [perl #60156].
5076a392
FC
3336
3337=item *
3338
e8e35311
FC
3339Matching a Unicode character against an alternation containing characters
3340that happened to match continuation bytes in the former's UTF8
3341representation (C<qq{\x{30ab}} =~ /\xab|\xa9/>) would cause erroneous
3342warnings [perl #70998].
5076a392
FC
3343
3344=item *
3345
e8e35311
FC
3346The trie optimisation was not taking empty groups into account, preventing
3347'foo' from matching C</\A(?:(?:)foo|bar|zot)\z/> [perl #78356].
5076a392
FC
3348
3349=item *
3350
e8e35311
FC
3351A pattern containing a C<+> inside a lookahead would sometimes cause an
3352incorrect match failure in a global match (e.g., C</(?=(\S+))/g>)
3353[perl #68564].
5076a392
FC
3354
3355=item *
3356
e8e35311
FC
3357A regular expression optimisation would sometimes cause a match with a
3358C<{n,m}> quantifier to fail when it should match [perl #79152].
5076a392
FC
3359
3360=item *
3361
e8e35311 3362Case insensitive matching in regular expressions compiled under C<use
438c239f
FC
3363locale> now works much more sanely when the pattern or
3364target string is encoded internally in
3365UTF8. Previously, under these conditions the localeness
e8e35311
FC
3366was completely lost. Now, code points above 255 are treated as Unicode,
3367but code points between 0 and 255 are treated using the current locale
438c239f
FC
3368rules, regardless of whether the pattern or the string is encoded in UTF8.
3369The few case-insensitive matches that cross the 255/256 boundary are not
e8e35311
FC
3370allowed. For example, 0xFF does not caselessly match the character at
33710x178, LATIN CAPITAL LETTER Y WITH DIAERESIS, because 0xFF may not be
3372LATIN SMALL LETTER Y in the current locale, and Perl has no way of
3373knowing if that character even exists in the locale, much less what code
3374point it is.
5076a392
FC
3375
3376=item *
3377
e8e35311
FC
3378The C<(?|...)> regular expression construct no longer crashes if the final
3379branch has more sets of capturing parentheses than any other branch. This
3380was fixed in Perl 5.10.1 for the case of a single branch, but that fix did
3381not take multiple branches into account [perl #84746].
5076a392
FC
3382
3383=item *
3384
e8e35311
FC
3385A bug has been fixed in the implementation of C<{...}> quantifiers in
3386regular expressions that prevented the code block in
3387C</((\w+)(?{ print $2 })){2}/> from seeing the C<$2> sometimes
3388[perl #84294].
5076a392 3389
e8e35311 3390=back
5076a392 3391
e8e35311
FC
3392=head2 Syntax/Parsing Bugs
3393
3394=over
5076a392
FC
3395
3396=item *
3397
e8e35311 3398C<when(scalar){...}> no longer crashes, but produces a syntax error
cdc10f43 3399[perl #74114] (5.12.1).
5076a392
FC
3400
3401=item *
3402
e8e35311
FC
3403A label right before a string eval (C<foo: eval $string>) no longer causes
3404the label to be associated also with the first statement inside the eval
3405[perl #74290] (5.12.1).
5076a392
FC
3406
3407=item *
3408
b2c076b5 3409The C<no 5.13.2;> form of C<no> no longer tries to turn on features or
d430b8e7 3410pragmata (i.e., strict) [perl #70075] (5.12.2).
5076a392
FC
3411
3412=item *
3413
b2c076b5
FC
3414C<BEGIN {require 5.12.0}> now behaves as documented, rather than behaving
3415identically to C<use 5.12.0;>. Previously, C<require> in a C<BEGIN> block
3416was erroneously executing the C<use feature ':5.12.0'> and
3417C<use strict;> behaviour, which only C<use> was documented to
3418provide [perl #69050].
5076a392
FC
3419
3420=item *
3421
5076a392
FC
3422A regression introduced in Perl 5.12.0, making
3423C<< my $x = 3; $x = length(undef) >> result in C<$x> set to C<3> has been
d430b8e7 3424fixed. C<$x> will now be C<undef> [perl #85508] (5.12.2).
b2c076b5
FC
3425
3426=item *
3427
3428When strict 'refs' mode is off, C<%{...}> in rvalue context returns
3429C<undef> if its argument is undefined. An optimisation introduced in perl
34305.12.0 to make C<keys %{...}> faster when used as a boolean did not take
3431this into account, causing C<keys %{+undef}> (and C<keys %$foo> when
3432C<$foo> is undefined) to be an error, which it should only be in strict
3433mode [perl #81750].
5076a392
FC
3434
3435=item *
3436
e8e35311 3437Constant-folding used to cause
5076a392 3438
e8e35311 3439 $text =~ ( 1 ? /phoo/ : /bear/)
5076a392 3440
e8e35311
FC
3441to turn into
3442
3443 $text =~ /phoo/
3444
3445at compile time. Now it correctly matches against C<$_> [perl #20444].
5076a392
FC
3446
3447=item *
3448
e8e35311
FC
3449Parsing Perl code (either with string C<eval> or by loading modules) from
3450within a C<UNITCHECK> block no longer causes the interpreter to crash
3451[perl #70614].
5076a392
FC
3452
3453=item *
3454
b2c076b5
FC
3455String evals no longer fail after 2 billion scopes have been
3456compiled [perl #83364].
3457
3458=item *
3459
e8e35311
FC
3460The parser no longer hangs when encountering certain Unicode characters,
3461such as U+387 [perl #74022].
5076a392
FC
3462
3463=item *
3464
b2c076b5
FC
3465Several contexts no longer allow a Unicode character to begin a word
3466that should never begin words, for an example an accent that must follow
3467another character previously could precede all other characters.
5076a392
FC
3468
3469=item *
3470
e8e35311
FC
3471Defining a constant with the same name as one of perl's special blocks
3472(e.g., INIT) stopped working in 5.12.0, but has now been fixed
3473[perl #78634].
5076a392
FC
3474
3475=item *
3476
e8e35311
FC
3477A reference to a literal value used as a hash key (C<$hash{\"foo"}>) used
3478to be stringified, even if the hash was tied [perl #79178].
5076a392
FC
3479
3480=item *
3481
e8e35311
FC
3482A closure containing an C<if> statement followed by a constant or variable
3483is no longer treated as a constant [perl #63540].
5076a392
FC
3484
3485=item *
3486
e8e35311
FC
3487C<state> can now be used with attributes. It used to mean the same thing as
3488C<my> if attributes were present [perl #68658].
5076a392
FC
3489
3490=item *
3491
e8e35311
FC
3492Expressions like C<< @$a > 3 >> no longer cause C<$a> to be mentioned in
3493the "Use of uninitialized value in numeric gt" warning when C<$a> is
3494undefined (since it is not part of the C<E<gt>> expression, but the operand
3495of the C<@>) [perl #72090].
5076a392
FC
3496
3497=item *
3498
e8e35311
FC
3499Accessing an element of a package array with a hard-coded number (as
3500opposed to an arbitrary expression) would crash if the array did not exist.
3501Usually the array would be autovivified during compilation, but typeglob
3502manipulation could remove it, as in these two cases which used to crash:
5076a392 3503
e8e35311
FC
3504 *d = *a; print $d[0];
3505 undef *d; print $d[0];
5076a392 3506
2c389f6c
FC
3507=item *
3508
3509The C<-C> command line option, when used on the shebang line, can now be
3510followed by other options [perl #72434].
3511
3512=item *
3513
3514The C<B> module was returning C<B::OP>s instead of C<B::LOGOP>s for C<entertry> [perl #80622].
3515This was due to a bug in the perl core, not in C<B> itself.
3516
e8e35311 3517=back
5076a392 3518
e262cb24
FC
3519=head2 Stashes, Globs and Method Lookup
3520
3521Perl 5.10.0 introduced a new internal mechanism for caching MROs (method
3522resolution orders, or lists of parent classes; aka "isa" caches) to make
3523method lookup faster (so @ISA arrays would not have to be searched
3524repeatedly). Unfortunately, this brought with it quite a few bugs. Almost
3525all of these have been fixed now, along with a few MRO-related bugs that
3526existed before 5.10.0:
3527
3528=over
3529
3530=item *
3531
3532The following used to have erratic effects on method resolution, because
3533the "isa" caches were not reset or otherwise ended up listing the wrong
3534classes. These have been fixed.
3535
3536=over
3537
3538=item Aliasing packages by assigning to globs [perl #77358]
3539
3540=item Deleting packages by deleting their containing stash elements
3541
3542=item Undefining the glob containing a package (C<undef *Foo::>)
3543
3544=item Undefining an ISA glob (C<undef *Foo::ISA>)
3545
3546=item Deleting an ISA stash element (C<delete $Foo::{ISA}>)
3547
3548=item Sharing @ISA arrays between classes (via C<*Foo::ISA = \@Bar::ISA> or
3549C<*Foo::ISA = *Bar::ISA>) [perl #77238]
3550
3551=back
3552
3553C<undef *Foo::ISA> would even stop a new C<@Foo::ISA> array from updating
3554caches.
3555
3556=item *
3557
3558Typeglob assignments would crash if the glob's stash no longer existed, so
3559long as the glob assigned to was named 'ISA' or the glob on either side of
3560the assignment contained a subroutine.
3561
3562=item *
3563
3564C<PL_isarev>, which is accessible to Perl via C<mro::get_isarev> is now
3565updated properly when packages are deleted or removed from the C<@ISA> of
3566other classes. This allows many packages to be created