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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
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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>):
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570
571 use re qw(regexp_pattern);
572 my ($pat, $mods) = regexp_pattern($re_ref);
573
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574If the actual stringification is important, or older Perls need to be
575supported, you can use something like the following:
576
577 # Accept both old and new-style stringification
578 my $modifiers = (qr/foobar/ =~ /\Q(?^/) ? '^' : '-xism';
579
580And then use C<$modifiers> instead of C<-xism>.
581
61752d82 582=head3 Run-time code blocks in regular expressions inherit pragmata
5076a392 583
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584Code blocks in regular expressions (C<(?{...})> and C<(??{...})>) used not
585to inherit any pragmata (strict, warnings, etc.) if the regular expression
586was compiled at run time as happens in cases like these two:
5076a392 587
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588 use re 'eval';
589 $foo =~ $bar; # when $bar contains (?{...})
590 $foo =~ /$bar(?{ $finished = 1 })/;
591
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
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614C<defined %Foo::> now always returns true, even when no symbols have yet been
615defined in that package.
5076a392 616
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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
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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>.)
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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<*$glob> on the second line returns a new immutable glob. That new
662glob is made an alias to C<*bar>. Then it is discarded. So the second
663assignment has no effect.
664
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665See L<http://rt.perl.org/rt3/Public/Bug/Display.html?id=77810> for even
666more detail.
667
61752d82 668=head3 Clearing stashes
5076a392
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669
670Stash list assignment C<%foo:: = ()> used to make the stash anonymous
671temporarily while it was being emptied. Consequently, any of its
672subroutines referenced elsewhere would become anonymous (showing up as
673"(unknown)" in C<caller>). Now they retain their package names, such that
674C<caller> will return the original sub name if there is still a reference
675to its typeglob, or "foo::__ANON__" otherwise [perl #79208].
676
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677=head3 Magic variables outside the main package
678
679In previous versions of Perl, magic variables like C<$!>, 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
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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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FC
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 $bar >> but will issue a warning.
5076a392 844
e683df94
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845=head2 C<\cI<X>>
846
847The backslash-c construct was designed as a way of specifying
848non-printable characters, but there were no restrictions (on ASCII
849platforms) on what the character following the C<c> could be. Now,
850a deprecation warning is raised if that character isn't an ASCII character.
851Also, a deprecation warning is raised for C<"\c{"> (which is the same
852as simply saying C<";">).
853
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854=head2 C<"\b{"> and C<"\B{">
855
856In regular expressions, a literal C<"{"> immediately following a C<"\b">
857(not in a bracketed character class) or a C<"\B{"> is now deprecated
858to allow for its future use by Perl itself.
859
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860=head2 Deprecation warning added for deprecated-in-core .pl libs
861
862This is a mandatory warning, not obeying -X or lexical warning bits.
863The warning is modelled on that supplied by deprecate.pm for
864deprecated-in-core .pm libraries. It points to the specific CPAN
823d0e46
FC
865distribution that contains the .pl libraries. The CPAN version, of
866course, does not generate the warning.
5076a392
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867
868=head2 List assignment to C<$[>
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.
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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:
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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)>.
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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
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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
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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
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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
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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
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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
5076a392
FC
1186C<Archive::Extract> has been upgraded from version 0.38 to 0.48.
1187
1188Updates since 0.38 include: a safe print method that guards
1189Archive::Extract from changes to $\; a fix to the tests when run in core
1984204c
FC
1190perl; support for TZ files; a modification for the lzma
1191logic to favour IO::Uncompress::Unlzma; and a fix
1192for an issue with NetBSD-current and its new unzip
5076a392
FC
1193executable.
1194
1195=item *
1196
1197C<Archive::Tar> has been upgraded from version 1.54 to 1.76.
1198
1984204c
FC
1199Important changes since 1.54 include the following:
1200
1201=over
1202
1203=item *
1204
1205Compatibility with busybox implementations of tar
1206
1207=item *
1208
1209A fix so that C<write()> and C<create_archive()>
1210close only handles they opened
1211
1212=item *
1213
1214A bug was fixed regarding the exit code of extract_archive.
5076a392 1215
1984204c
FC
1216=item *
1217
4f978a3b 1218The C<ptar> utility has a new option to allow safe
5076a392
FC
1219creation of tarballs without world-writable files on Windows, allowing those
1220archives to be uploaded to CPAN.
1221
1984204c
FC
1222=item *
1223
1224A new ptargrep utility for using regular expressions against
5076a392
FC
1225the contents of files in a tar archive.
1226
1984204c
FC
1227=item *
1228
1229Pax extended headers are now skipped.
1230
1231=back
5076a392
FC
1232
1233=item *
1234
5076a392
FC
1235C<B> has been upgraded from version 1.23 to 1.27.
1236
1237It no longer crashes when taking apart a C<y///> containing characters
1238outside the octet range or compiled in a C<use utf8> scope.
1239
1240The size of the shared object has been reduced by about 40%, with no
1241reduction in functionality.
1242
1243=item *
1244
1245C<B::Concise> has been upgraded from version 0.78 to 0.82.
1246
1247B::Concise marks rv2sv, rv2av and rv2hv ops with the new OPpDEREF flag
1248as "DREFed".
1249
1250It no longer produces mangled output with the C<-tree> option
1251[perl #80632].
1252
1253=item *
1254
c67a4e29 1255C<B::Deparse> has been upgraded from version 0.96 to 1.03.
5076a392 1256
1984204c 1257The deparsing of a nextstate op has changed when it has both a
5076a392
FC
1258change of package (relative to the previous nextstate), or a change of
1259C<%^H> or other state, and a label. Previously the label was emitted
cdc10f43 1260first, but now the label is emitted last (5.12.1).
5076a392 1261
5a553547
FC
1262The C<no 5.13.2> or similar form is now correctly handled by B::Deparse
1263(5.12.3).
5076a392
FC
1264
1265B::Deparse now properly handles the code that applies a conditional
1266pattern match against implicit C<$_> as it was fixed in [perl #20444].
1267
1984204c
FC
1268Deparsing of C<our> followed by a variable with funny characters
1269(as permitted under the C<utf8> pragma) has also been fixed [perl #33752].
5076a392
FC
1270
1271=item *
1272
e539ae69
FR
1273C<bignum> has been upgraded from version 0.23 to 0.26.
1274
1275=item *
1276
c74c1fa8 1277C<Carp> has been upgraded from version 1.15 to 1.20.
5076a392
FC
1278
1279L<Carp> now detects incomplete L<caller()|perlfunc/"caller EXPR"> overrides and
d430b8e7
FC
1280avoids using bogus C<@DB::args>. To provide backtraces,
1281Carp relies on particular behaviour of the C<caller>
1282built-in. Carp now detects if other code has
5076a392 1283overridden this with an incomplete implementation, and modifies its backtrace
d430b8e7
FC
1284accordingly. Previously incomplete overrides would cause incorrect values
1285in backtraces (best case), or obscure fatal errors (worst case).
5076a392
FC
1286
1287This fixes certain cases of C<Bizarre copy of ARRAY> caused by modules
d430b8e7 1288overriding C<caller()> incorrectly (5.12.2).
5076a392 1289
1984204c 1290It now also avoids using regular expressions that cause perl to
5076a392
FC
1291load its Unicode tables, in order to avoid the 'BEGIN not safe after
1292errors' error that will ensue if there has been a syntax error
1293[perl #82854].
1294
1295=item *
1296
9eb7ad55 1297C<CGI> has been upgraded from version 3.48 to 3.52.
5076a392
FC
1298
1299This provides the following security fixes: the MIME boundary in
1984204c
FC
1300multipart_init is now random and the handling of
1301newlines embedded in header values has been improved.
5076a392
FC
1302
1303=item *
1304
5076a392
FC
1305C<Compress::Raw::Bzip2> has been upgraded from version 2.024 to 2.033.
1306
1984204c 1307It has been updated to use bzip2 1.0.6.
5076a392
FC
1308
1309=item *
1310
51090521
FR
1311C<Compress::Raw::Zlib> has been upgraded from version 2.024 to 2.033.
1312
1313=item *
1314
f75b7efc 1315C<CPAN> has been upgraded from version 1.94_56 to 1.9600.
1984204c
FC
1316
1317Major highlights:
5076a392
FC
1318
1319=over 4
1320
1984204c 1321=item * much less configuration dialog hassle
5076a392 1322
1984204c 1323=item * support for META/MYMETA.json
5076a392 1324
1984204c 1325=item * support for local::lib
5076a392 1326
1984204c 1327=item * support for HTTP::Tiny to reduce the dependency on ftp sites
5076a392 1328
1984204c 1329=item * automatic mirror selection
5076a392 1330
1984204c 1331=item * iron out all known bugs in configure_requires
5076a392 1332
1984204c
FC
1333=item * support for distributions compressed with bzip2
1334
1335=item * allow Foo/Bar.pm on the commandline to mean Foo::Bar
1336
1337=back
5076a392
FC
1338
1339=item *
1340
d430b8e7
FC
1341C<CPANPLUS> has been upgraded from version 0.90 to 0.9103.
1342
1343A change to F<cpanp-run-perl>
1344resolves L<RT #55964|http://rt.cpan.org/Public/Bug/Display.html?id=55964>
1345and L<RT #57106|http://rt.cpan.org/Public/Bug/Display.html?id=57106>, both
1346of which related to failures to install distributions that use
1347C<Module::Install::DSL> (5.12.2).
5076a392 1348
1984204c
FC
1349A dependency on Config was not recognised as a
1350core module dependency. This has been fixed.
5076a392 1351
1984204c 1352CPANPLUS now includes support for META.json and MYMETA.json.
5076a392
FC
1353
1354=item *
1355
4467e8f7
FR
1356C<CPANPLUS::Dist::Build> has been upgraded from version 0.46 to 0.54.
1357
1358=item *
1359
5076a392
FC
1360C<Data::Dumper> has been upgraded from version 2.125 to 2.130_02.
1361
4ed2cea4
FC
1362The indentation used to be off when C<$Data::Dumper::Terse> was set. This
1363has been fixed [perl #73604].
1364
1984204c
FC
1365This upgrade also fixes a crash when using custom sort functions that might
1366cause the stack to change [perl #74170].
5076a392
FC
1367
1368C<Dumpxs> no longer crashes with globs returned by C<*$io_ref>
1369[perl #72332].
1370
1371=item *
1372
549d34f5
FR
1373C<DB_File> has been upgraded from version 1.820 to 1.821.
1374
1375=item *
1376
5076a392
FC
1377C<Devel::DProf> has been upgraded from version 20080331.00 to 20110228.00.
1378
1379Merely loading C<Devel::DProf> now no longer triggers profiling to start.
1380C<use Devel::DProf> and C<perl -d:DProf ...> still behave as before and start
1381the profiler.
1382
1383NOTE: C<Devel::DProf> is deprecated and will be removed from a future
1984204c 1384version of Perl. We strongly recommend that you install and use
5076a392
FC
1385L<Devel::NYTProf> instead, as it offers significantly improved
1386profiling and reporting.
1387
1388=item *
1389
66899ca3
FR
1390C<Devel::SelfStubber> has been upgraded from version 1.03 to 1.05.
1391
1392=item *
1393
5076a392
FC
1394C<diagnostics> has been upgraded from version 1.19 to 1.22.
1395
1396It now renders pod links slightly better, and has been taught to find
1397descriptions for messages that share their descriptions with other
1398messages.
1399
1400=item *
1401
1402C<Digest::MD5> has been upgraded from version 2.39 to 2.51.
1403
1404It is now safe to use this module in combination with threads.
1405
1406=item *
1407
1408C<Digest::SHA> has been upgraded from version 5.47 to 5.61.
1409
1410C<shasum> now more closely mimics C<sha1sum>/C<md5sum>.
1411
1412C<Addfile> accepts all POSIX filenames.
1413
1984204c
FC
1414New SHA-512/224 and SHA-512/256 transforms (ref. NIST Draft FIPS 180-4
1415[February 2011])
5076a392
FC
1416
1417=item *
1418
e53cbaa3
FR
1419C<Dumpvalue> has been upgraded from version 1.13 to 1.16.
1420
1421=item *
1422
31e8b85a 1423C<DynaLoader> has been upgraded from version 1.10 to 1.13.
5076a392
FC
1424
1425It fixes a buffer overflow when passed a very long file name.
1426
1427It no longer inherits from AutoLoader; hence it no longer
1428produces weird error messages for unsuccessful method calls on classes that
1429inherit from DynaLoader [perl #84358].
1430
1431=item *
1432
1433C<Encode> has been upgraded from version 2.39 to 2.42.
1434
1435Now, all 66 Unicode non-characters are treated the same way U+FFFF has
1984204c
FC
1436always been treated; in cases when it was disallowed, all 66 are
1437disallowed; in those cases where it warned, all 66 warn.
5076a392
FC
1438
1439=item *
1440
68f90ac3
FR
1441C<Env> has been upgraded from version 1.01 to 1.02.
1442
1443=item *
1444
5076a392
FC
1445C<Errno> has been upgraded from version 1.11 to 1.13.
1446
1447The implementation of C<Errno> has been refactored to use about 55% less memory.
5076a392
FC
1448
1449On some platforms with unusual header files, like Win32/gcc using mingw64
1450headers, some constants which weren't actually error numbers have been exposed
1451by C<Errno>. This has been fixed [perl #77416].
1452
1453=item *
1454
1455C<Exporter> has been upgraded from version 5.64_01 to 5.64_03.
1456
1457Exporter no longer overrides C<$SIG{__WARN__}> [perl #74472]
1458
1459=item *
1460
25fe7f8f
FR
1461C<ExtUtils::CBuilder> has been upgraded from version 0.27 to 0.280202.
1462
1463=item *
1464
2292e71e
FR
1465C<ExtUtils::Command> has been upgraded from version 1.16 to 1.17.
1466
1467=item *
1468
5076a392
FC
1469C<ExtUtils::Constant> has been upgraded from 0.22 to 0.23.
1470
1471The C<AUTOLOAD> helper code generated by C<ExtUtils::Constant::ProxySubs>
1472can now C<croak> for missing constants, or generate a complete C<AUTOLOAD>
1984204c
FC
1473subroutine in XS, allowing simplification of many modules that use it
1474(C<Fcntl>, C<File::Glob>, C<GDBM_File>, C<I18N::Langinfo>, C<POSIX>,
1475C<Socket>).
5076a392
FC
1476
1477C<ExtUtils::Constant::ProxySubs> can now optionally push the names of all
1984204c 1478constants onto the package's C<@EXPORT_OK>.
5076a392
FC
1479
1480=item *
1481
588c5853
FR
1482C<ExtUtils::Install> has been upgraded from version 1.55 to 1.56.
1483
1484=item *
1485
5418ffb3
FR
1486C<ExtUtils::MakeMaker> has been upgraded from version 6.56 to 6.57_05.
1487
1488=item *
1489
f40ab45f
FR
1490C<ExtUtils::Manifest> has been upgraded from version 1.57 to 1.58.
1491
1492=item *
1493
b7064dd7
FR
1494C<ExtUtils::ParseXS> has been upgraded from version 2.21 to 2.2209.
1495
1496=item *
1497
05102622
FR
1498C<File::CheckTree> has been upgraded from version 4.4 to 4.41.
1499
1500=item *
1501
e12786fa 1502C<File::DosGlob> has been upgraded from version 1.01 to 1.04.
5076a392
FC
1503
1504It allows patterns containing literal parentheses (they no longer need to
1984204c
FC
1505be escaped). On Windows, it no longer
1506adds an extra F<./> to the file names
5076a392
FC
1507returned when the pattern is a relative glob with a drive specification,
1508like F<c:*.pl> [perl #71712].
1509
1510=item *
1511
1512C<File::Fetch> has been upgraded from version 0.24 to 0.32.
1513
1514C<HTTP::Lite> is now supported for 'http' scheme.
1515
1516The C<fetch> utility is supported on FreeBSD, NetBSD and
1517Dragonfly BSD for the C<http> and C<ftp> schemes.
1518
1519=item *
1520
23f2cbb1 1521C<File::Find> has been upgraded from version 1.15 to 1.19.
5076a392 1522
1984204c 1523It improves handling of backslashes on Windows, so that paths like
5076a392
FC
1524F<c:\dir\/file> are no longer generated [perl #71710].
1525
1526=item *
1527
d430b8e7
FC
1528C<File::Spec> has been upgraded from version 3.31 to 3.33.
1529
1530Several portability fixes were made in C<File::Spec::VMS>: a colon is now
1531recognized as a delimiter in native filespecs; caret-escaped delimiters are
1532recognized for better handling of extended filespecs; C<catpath()> returns
1533an empty directory rather than the current directory if the input directory
1534name is empty; C<abs2rel()> properly handles Unix-style input (5.12.2).
1535
1536=item *
1537
46ba0657 1538C<File::stat> has been upgraded from 1.02 to 1.05.
5076a392
FC
1539
1540The C<-x> and C<-X> file test operators now work correctly under the root
1541user.
1542
1543=item *
1544
b7edcc3c
FR
1545C<Filter::Simple> has been upgraded from version 0.84 to 0.86.
1546
1547=item *
1548
dc6857fd 1549C<GDBM_File> has been upgraded from 1.10 to 1.14.
5076a392
FC
1550
1551This fixes a memory leak when DBM filters are used.
1552
1553=item *
1554
6e107b45 1555C<Hash::Util> has been upgraded from 0.07 to 0.11.
5076a392 1556
1984204c
FC
1557Hash::Util no longer emits spurious "uninitialized" warnings when
1558recursively locking hashes that have undefined values [perl #74280].
5076a392
FC
1559
1560=item *
1561
eec33fe6
FR
1562C<I18N::Collate> has been upgraded from version 1.01 to 1.02.
1563
1564=item *
1565
ad5f8f47 1566C<I18N::Langinfo> has been upgraded from version 0.03 to 0.08.
5076a392
FC
1567
1568C<langinfo()> now defaults to using C<$_> if there is no argument given, just
5334145a 1569as the documentation has always claimed.
5076a392
FC
1570
1571=item *
1572
c41635f7
FR
1573C<I18N::LangTags> has been upgraded from version 0.35 to 0.35_01.
1574
1575=item *
1576
98a6a4ff
FR
1577C<if> has been upgraded from version 0.05 to 0.0601.
1578
1579=item *
1580
f6ff7fb6
FR
1581C<IO> has been upgraded from version 1.25_02 to 1.25_04.
1582
1583=item *
1584
d13528c5 1585C<IO::Select> has been upgraded from version 1.17 to 1.20.
5076a392
FC
1586
1587It now allows IO::Handle objects (and objects in derived classes) to be
1588removed from an IO::Select set even if the underlying file descriptor is
1589closed or invalid.
1590
1591=item *
1592
d07561d3 1593C<IPC::Cmd> has been upgraded from version 0.54 to 0.70.
5076a392 1594
1984204c
FC
1595Resolves an issue with splitting Win32 command lines. An argument
1596consisting of the single character "0" used to be omitted (CPAN RT #62961).
5076a392
FC
1597
1598=item *
1599
3f16e4eb 1600C<IPC::Open3> has been upgraded from 1.05 to 1.09.
5076a392 1601
4ed2cea4
FC
1602C<open3> now produces an error if the C<exec> call fails, allowing this
1603condition to be distinguished from a child process that exited with a
1604non-zero status [perl #72016].
1605
5076a392
FC
1606The internal C<xclose> routine now knows how to handle file descriptors, as
1607documented, so duplicating STDIN in a child process using its file
1608descriptor now works [perl #76474].
1609
1610=item *
1611
c8b41807
FR
1612C<IPC::SysV> has been upgraded from version 2.01 to 2.03.
1613
1614=item *
1615
ef79f038
FR
1616C<lib> has been upgraded from version 0.62 to 0.63.
1617
1618=item *
1619
5b1884f4 1620C<Locale::Maketext> has been upgraded from version 1.14 to 1.19.
5076a392 1621
1984204c 1622Locale::Maketext now supports external caches.
5076a392 1623
1984204c
FC
1624This upgrade also fixes an infinite loop in
1625C<Locale::Maketext::Guts::_compile()> when
5076a392
FC
1626working with tainted values (CPAN RT #40727).
1627
1984204c 1628C<< ->maketext >> calls will now back up and restore C<$@> so that error
5076a392
FC
1629messages are not suppressed (CPAN RT #34182).
1630
1631=item *
1632
3811bd2b
FR
1633C<Log::Message> has been upgraded from version 0.02 to 0.04.
1634
1635=item *
1636
8eb65377
FR
1637C<Log::Message::Simple> has been upgraded from version 0.06 to 0.08.
1638
1639=item *
1640
5076a392
FC
1641C<Math::BigInt> has been upgraded from version 1.89_01 to 1.994.
1642
1643This fixes, among other things, incorrect results when computing binomial
1644coefficients [perl #77640].
1645
1984204c 1646It also prevents C<sqrt($int)> from crashing under C<use bigrat;>
5076a392
FC
1647[perl #73534].
1648
1649=item *
1650
846c1cec
FR
1651C<Math::BigInt::FastCalc> has been upgraded from version 0.19 to 0.28.
1652
1653=item *
1654
fce4aef3
FR
1655C<Math::BigRat> has been upgraded from version 0.24 to 0.26_02.
1656
1657=item *
1658
12e26027
FR
1659C<Memoize> has been upgraded from version 1.01_03 to 1.02.
1660
1661=item *
1662
5076a392
FC
1663C<MIME::Base64> has been upgraded from 3.08 to 3.13.
1664
1665Includes new functions to calculate the length of encoded and decoded
1666base64 strings.
1667
1668Now provides C<encode_base64url> and C<decode_base64url> functions to process
1669the base64 scheme for "URL applications".
1670
1671=item *
1672
1673C<Module::Build> has been upgraded from version 0.3603 to 0.3800.
1674
1675A notable change is the deprecation of several modules.
1676Module::Build::Version has been deprecated and Module::Build now relies
1677directly upon L<version>. Module::Build::ModuleInfo has been deprecated in
1678favor of a standalone copy of it called L<Module::Metadata>.
1679Module::Build::YAML has been deprecated in favor of L<CPAN::Meta::YAML>.
1680
1681Module::Build now also generates META.json and MYMETA.json files
1682in accordance with version 2 of the CPAN distribution metadata specification,
1683L<CPAN::Meta::Spec>. The older format META.yml and MYMETA.yml files are
1684still generated, as well.
1685
1686=item *
1687
7259fe26 1688C<Module::CoreList> has been upgraded from version 2.29 to 2.47.
5076a392
FC
1689
1690Besides listing the updated core modules of this release, it also stops listing
1984204c 1691the C<Filespec> module. That module never existed in core. The scripts
5076a392 1692generating C<Module::CoreList> confused it with C<VMS::Filespec>, which actually
1984204c 1693is a core module as of perl 5.8.7.
5076a392
FC
1694
1695=item *
1696
193af05b
FR
1697C<Module::Load> has been upgraded from version 0.16 to 0.18.
1698
1699=item *
1700
5b3a054f
FR
1701C<Module::Load::Conditional> has been upgraded from version 0.34 to 0.44.
1702
1703=item *
1704
4f978a3b
FR
1705C<NDBM_File> has been upgraded from version 1.08 to 1.11.
1706
1707This fixes a memory leak when DBM filters are used.
1708
1709=item *
1710
d0aa5c91
FR
1711C<Net::Ping> has been upgraded from version 2.36 to 2.38.
1712
1713=item *
1714
d44b8a8c
FR
1715C<NEXT> has been upgraded from version 0.64 to 0.65.
1716
1717=item *
1718
678d4fd4
FR
1719C<Object::Accessor> has been upgraded from version 0.36 to 0.38.
1720
1721=item *
1722
34188656 1723C<ODBM_File> have been upgraded from version 1.07 to 1.10.
5076a392
FC
1724
1725This fixes a memory leak when DBM filters are used.
1726
1727=item *
1728
77be713d 1729C<overload> has been upgraded from 1.10 to 1.12.
5076a392
FC
1730
1731C<overload::Method> can now handle subroutines that are themselves blessed
1732into overloaded classes [perl #71998].
1733
5076a392
FC
1734The documentation has greatly improved. See L</Documentation> below.
1735
1736=item *
1737
f84c796e
FR
1738C<Params::Check> has been upgraded from version 0.26 to 0.28.
1739
1740=item *
1741
550ee92b
FR
1742C<parent> has been upgraded from version 0.223 to 0.225.
1743
1744=item *
1745
5076a392
FC
1746C<Parse::CPAN::Meta> has been upgraded from version 1.40 to 1.4401.
1747
1984204c 1748The latest Parse::CPAN::Meta can now read YAML and JSON files using
5076a392
FC
1749L<CPAN::Meta::YAML> and L<JSON::PP>, which are now part of the Perl core.
1750
1751=item *
1752
5076a392
FC
1753C<PerlIO::scalar> has been upgraded from 0.07 to 0.11.
1754
1755A C<read> after a C<seek> beyond the end of the string no longer thinks it
1756has data to read [perl #78716].
1757
1758=item *
1759
be3c8498
FR
1760C<Pod::LaTeX> has been upgraded from version 0.58 to 0.59.
1761
1762=item *
1763
fd8a2e89
FR
1764C<Pod::Perldoc> has been upgraded from version 3.15_02 to 3.15_03.
1765
1766=item *
1767
5bcb6583
FR
1768C<Pod::Simple> has been upgraded from version 3.13 to 3.16.
1769
1770=item *
1771
abb8c779 1772C<POSIX> has been upgraded from 1.19 to 1.24.
5076a392
FC
1773
1774It now includes constants for POSIX signal constants.
1775
1776=item *
1777
1984204c 1778C<re> has been upgraded from version 0.11 to 0.17.
5076a392
FC
1779
1780New C<use re "/flags"> pragma
1781
5076a392 1782The C<regmust> function used to crash when called on a regular expression
1984204c 1783belonging to a pluggable engine. Now it croaks instead.
5076a392
FC
1784
1785C<regmust> no longer leaks memory.
1786
1787=item *
1788
1789C<Safe> has been upgraded from version 2.25 to 2.29.
1790
cdc10f43
FC
1791Coderefs returned by C<reval()> and C<rdo()> are now wrapped via
1792C<wrap_code_refs> (5.12.1).
1793
5076a392
FC
1794This fixes a possible infinite loop when looking for coderefs.
1795
cdc10f43 1796It adds several version::vxs::* routines to the default share.
5076a392
FC
1797
1798=item *
1799
5076a392
FC
1800C<SelfLoader> has been upgraded from 1.17 to 1.18.
1801
1802It now works in taint mode [perl #72062].
1803
1804=item *
1805
1806C<sigtrap> has been upgraded from version 1.04 to 1.05.
1807
1808It no longer tries to modify read-only arguments when generating a
1809backtrace [perl #72340].
1810
1811=item *
1812
1984204c 1813C<Socket> has been upgraded from version 1.87 to 1.94.
5076a392 1814
1984204c 1815See L</IPv6 support>, above.
5076a392
FC
1816
1817=item *
1818
1819C<Storable> has been upgraded from version 2.22 to 2.27.
1820
1821Includes performance improvement for overloaded classes.
1822
5076a392 1823This adds support for serialising code references that contain UTF-8 strings
1984204c
FC
1824correctly. The Storable minor version
1825number changed as a result, meaning that
5076a392
FC
1826Storable users who set C<$Storable::accept_future_minor> to a C<FALSE> value
1827will see errors (see L<Storable/FORWARD COMPATIBILITY> for more details).
1828
1829Freezing no longer gets confused if the Perl stack gets reallocated
1830during freezing [perl #80074].
1831
1832=item *
1833
90c6e78f
FR
1834C<Term::ANSIColor> has been upgraded from version 2.02 to 3.00.
1835
1836=item *
1837
d9f2f059
FR
1838C<Term::UI> has been upgraded from version 0.20 to 0.26.
1839
1840=item *
1841
80ebb519
FR
1842C<Test::Harness> has been upgraded from version 3.17 to 3.23.
1843
1844=item *
1845
5076a392
FC
1846C<Test::Simple> has been upgraded from version 0.94 to 0.98.
1847
1848Among many other things, subtests without a C<plan> or C<no_plan> now have an
1849implicit C<done_testing()> added to them.
1850
1851=item *
1852
5076a392
FC
1853C<Thread::Semaphore> has been upgraded from version 2.09 to 2.12.
1854
1984204c
FC
1855It provides two new methods that give more control over the decrementing of
1856semaphores: C<down_nb> and C<down_force>.
5076a392
FC
1857
1858=item *
1859
f0d895e1
FR
1860C<Thread::Queue> has been upgraded from version 2.11 to 2.12.
1861
1862=item *
1863
1a6b954e
FR
1864C<threads> has been upgraded from version 1.75 to 1.83.
1865
1866=item *
1867
55816daa
FR
1868C<threads::shared> has been upgraded from version 1.32 to 1.36.
1869
1870=item *
1871
5076a392
FC
1872C<Tie::Hash> has been upgraded from version 1.03 to 1.04.
1873
1874Calling C<< Tie::Hash-E<gt>TIEHASH() >> used to loop forever. Now it C<croak>s.
1875
1876=item *
1877
ed68b07e
FR
1878C<Tie::RefHash> has been upgraded from version 1.38 to 1.39.
1879
1880=item *
1881
bb3c221a
FR
1882C<Time::HiRes> has been upgraded from version 1.9719 to 1.9721_01.
1883
1884=item *
1885
97fa568b
FR
1886C<Time::Local> has been upgraded from version 1.1901_01 to 1.2000.
1887
1888=item *
1889
a83cb732
FR
1890C<Time::Piece> has been upgraded from version 1.15_01 to 1.20_01.
1891
1892=item *
1893
5076a392
FC
1894C<Unicode::Collate> has been upgraded from version 0.52_01 to 0.73.
1895
1984204c 1896Unicode::Collate has been updated to use Unicode 6.0.0.
5076a392 1897
1984204c
FC
1898Unicode::Collate::Locale now supports a plethora of new locales: ar, be,
1899bg, de__phonebook, hu, hy, kk, mk, nso, om, tn, vi, hr, ig, ja, ko, ru, sq,
1900se, sr, to, uk, zh, zh__big5han, zh__gb2312han, zh__pinyin and zh__stroke.
5076a392
FC
1901
1902The following modules have been added:
1903
1904C<Unicode::Collate::CJK::Big5> for C<zh__big5han> which makes
1905tailoring of CJK Unified Ideographs in the order of CLDR's big5han ordering.
1906
1907C<Unicode::Collate::CJK::GB2312> for C<zh__gb2312han> which makes
1908tailoring of CJK Unified Ideographs in the order of CLDR's gb2312han ordering.
1909
1910C<Unicode::Collate::CJK::JISX0208> which makes tailoring of 6355 kanji
1911(CJK Unified Ideographs) in the JIS X 0208 order.
1912
1913C<Unicode::Collate::CJK::Korean> which makes tailoring of CJK Unified Ideographs
1914in the order of CLDR's Korean ordering.
1915
1916C<Unicode::Collate::CJK::Pinyin> for C<zh__pinyin> which makes
1917tailoring of CJK Unified Ideographs in the order of CLDR's pinyin ordering.
1918
1919C<Unicode::Collate::CJK::Stroke> for C<zh__stroke> which makes
1920tailoring of CJK Unified Ideographs in the order of CLDR's stroke ordering.
1921
5076a392
FC
1922This also sees the switch from using the pure-perl version of this
1923module to the XS version.
1924
1925=item *
1926
ec52b54b
FR
1927C<Unicode::Normalize> has been upgraded from version 1.03 to 1.10.
1928
1929=item *
1930
5076a392
FC
1931C<Unicode::UCD> has been upgraded from version 0.27 to 0.32.
1932
1984204c
FC
1933A new function, C<Unicode::UCD::num()>, has been added. This function
1934returns the numeric value of the string passed it or C<undef> if the string
1935in its entirety has no "safe" numeric value. (For more detail, and for the
1936definition of "safe", see L<Unicode::UCD/num>.)
5076a392 1937
1984204c 1938This upgrade also includes a number of bug fixes:
5076a392
FC
1939
1940=over 4
1941
1942=item charinfo()
1943
1944=over 4
1945
1946=item *
1947
1948It is now updated to Unicode Version 6 with Corrigendum #8, except,
1949as with Perl 5.14, the code point at U+1F514 has no name.
1950
1951=item *
1952
1953The Hangul syllable code points have the correct names, and their
1954decompositions are always output without requiring L<Lingua::KO::Hangul::Util>
1955to be installed.
1956
1957=item *
1958
54c7bb16
FC
1959The CJK (Chinese-Japanese-Korean) code points U+2A700 to U+2B734
1960and U+2B740 to U+2B81D are now properly handled.
5076a392
FC
1961
1962=item *
1963
1964The numeric values are now output for those CJK code points that have them.
1965
1966=item *
1967
1968The names that are output for code points with multiple aliases are now the
1969corrected ones.
1970
1971=back
1972
1973=item charscript()
1974
1975This now correctly returns "Unknown" instead of C<undef> for the script
1976of a code point that hasn't been assigned another one.
1977
1978=item charblock()
1979
1980This now correctly returns "No_Block" instead of C<undef> for the block
1981of a code point that hasn't been assigned to another one.
1982
1983=back
1984
5076a392
FC
1985=item *
1986
1987C<version> has been upgraded from 0.82 to 0.88.
1988
1984204c 1989Due to a bug, now fixed, the C<is_strict> and C<is_lax> functions did not
cdc10f43 1990work when exported (5.12.1).
5076a392
FC
1991
1992=item *
1993
3e625598 1994C<warnings> has been upgraded from version 1.09 to 1.12.
5076a392
FC
1995
1996Calling C<use warnings> without arguments is now significantly more efficient.
1997
4f978a3b
FR
1998=item *
1999
2000C<warnings::register> have been upgraded from version 1.01 to 1.02.
2001
5076a392
FC
2002It is now possible to register warning categories other than the names of
2003packages using C<warnings::register>. See L<perllexwarn> for more information.
2004
2005=item *
2006
62e270c2
FR
2007C<XSLoader> has been upgraded from version 0.10 to 0.13.
2008
2009=item *
2010
5076a392
FC
2011C<VMS::DCLsym> has been upgraded from version 1.03 to 1.05.
2012
2013Two bugs have been fixed [perl #84086]:
2014
2015The symbol table name was lost when tying a hash, due to a thinko in
2016C<TIEHASH>. The result was that all tied hashes interacted with the
2017local symbol table.
2018
2019Unless a symbol table name had been explicitly specified in the call
2020to the constructor, querying the special key ':LOCAL' failed to
2021identify objects connected to the local symbol table.
2022
2023=item *
2024
2025C<Win32> has been upgraded from version 0.39 to 0.44.
2026
1984204c
FC
2027This release has several new functions: C<Win32::GetSystemMetrics>,
2028C<Win32::GetProductInfo>, C<Win32::GetOSDisplayName>.
5076a392 2029
1984204c
FC
2030The names returned by C<Win32::GetOSName> and C<Win32::GetOSDisplayName>
2031have been corrected.
5076a392 2032
5076a392
FC
2033=back
2034
5076a392
FC
2035=head2 Removed Modules and Pragmata
2036
2037The following modules have been removed from the core distribution, and if
2038needed should be installed from CPAN instead.
2039
2040=over
2041
4f978a3b
FR
2042=item *
2043
2044C<Class::ISA> has been removed from the Perl core. Prior version was 0.36.
5076a392 2045
4f978a3b
FR
2046=item *
2047
2048C<Pod::Plainer> has been removed from the Perl core. Prior version was 1.02.
2049
2050=item *
5076a392 2051
4f978a3b 2052C<Switch> has been removed from the Perl core. Prior version was 2.16.
5076a392
FC
2053
2054=back
2055
2056The removal of C<Shell> has been deferred until after 5.14, as the
2057implementation of C<Shell> shipped with 5.12.0 did not correctly issue the
2058warning that it was to be removed from core.
2059
2060=head1 Documentation
2061
5076a392
FC
2062=head2 New Documentation
2063
41e29def 2064=head3 L<perlgpl>
5076a392
FC
2065
2066L<perlgpl> has been updated to contain GPL version 1, as is included in the
cdc10f43 2067F<README> distributed with perl (5.12.1).
5076a392 2068
41e29def 2069=head3 Perl 5.12.x delta files
5076a392 2070
41e29def
FC
2071The perldelta files for Perl 5.12.1 to 5.12.3 have been added from the
2072maintenance branch: L<perl5121delta>, L<perl5122delta>, L<perl5123delta>.
5076a392
FC
2073
2074=head3 L<perlpodstyle>
2075
2076New style guide for POD documentation,
2077split mostly from the NOTES section of the pod2man man page.
2078
41e29def
FC
2079=head3 L<perlsource>, L<perlinterp>, L<perlhacktut>, and L<perlhacktips>
2080
2081See L</L<perlhack> and perlrepository revamp>, below.
5076a392
FC
2082
2083=head2 Changes to Existing Documentation
2084
41e29def 2085=head3 L<perlmodlib> is now complete
4ed2cea4
FC
2086
2087The perlmodlib page that came with Perl 5.12.0 was missing a lot of
2088modules, due to a bug in the script that generates the list. This has been
cdc10f43 2089fixed [perl #74332] (5.12.1).
4ed2cea4 2090
41e29def 2091=head3 Replace wrong tr/// table in L<perlebcdic>
5076a392 2092
41e29def 2093L<perlebcdic> contains a helpful table to use in tr/// to convert
5076a392
FC
2094between EBCDIC and Latin1/ASCII. Unfortunately, the table was the
2095inverse of the one it describes, though the code that used the table
2096worked correctly for the specific example given.
2097
2098The table has been changed to its inverse, and the sample code changed
2099to correspond, as this is easier for the person trying to follow the
2100instructions since deriving the old table is somewhat more complicated.
2101
2102The table has also been changed to hex from octal, as that is more the norm
2103these days, and the recipes in the pod altered to print out leading
41e29def 2104zeros to make all the values the same length.
5076a392 2105
41e29def 2106=head3 Tricks for user-defined casing
5076a392 2107
41e29def
FC
2108L<perlunicode> now contains an explanation of how to override, mangle
2109and otherwise tweak the way perl handles upper-, lower- and other-case
2110conversions on Unicode data, and how to provide scoped changes to alter
2111one's own code's behaviour without stomping on anybody else.
5076a392
FC
2112
2113=head3 INSTALL explicitly states the requirement for C89
2114
d430b8e7
FC
2115This was already true but it's now Officially Stated For The Record
2116(5.12.2).
5076a392 2117
41e29def 2118=head3 Explanation of C<\xI<HH>> and C<\oI<OOO>> escapes
5076a392 2119
41e29def
FC
2120L<perlop> has been updated with more detailed explanation of these two
2121character escapes.
5076a392 2122
41e29def 2123=head3 C<-0I<NNN>> switch
5076a392 2124
41e29def 2125In L<perlrun>, the behavior of the C<-0NNN> switch for C<-0400> or higher
d430b8e7 2126has been clarified (5.12.2).
5076a392 2127
cdc10f43
FC
2128=head3 Maintenance policy
2129
2130L<perlpolicy> now contains the policy on what patches are acceptable for
2131maintenance branches (5.12.1).
2132
41e29def 2133=head3 Deprecation policy
5076a392 2134
41e29def 2135L<perlpolicy> now contains the policy on compatibility and deprecation
d430b8e7 2136along with definitions of terms like "deprecation" (5.12.2).
5076a392 2137
41e29def 2138=head3 New descriptions in L<perldiag>
5076a392
FC
2139
2140The following existing diagnostics are now documented:
2141
2142=over 4
2143
2144=item *
2145
2146L<Ambiguous use of %c resolved as operator %c|perldiag/"Ambiguous use of %c resolved as operator %c">
2147
2148=item *
2149
2150L<Ambiguous use of %c{%s} resolved to %c%s|perldiag/"Ambiguous use of %c{%s} resolved to %c%s">
2151
2152=item *
2153
2154L<Ambiguous use of %c{%s%s} resolved to %c%s%s|perldiag/"Ambiguous use of %c{%s%s} resolved to %c%s%s">
2155
2156=item *
2157
2158L<Ambiguous use of -%s resolved as -&%s()|perldiag/"Ambiguous use of -%s resolved as -&%s()">
2159
2160=item *
2161
2162L<Invalid strict version format (%s)|perldiag/"Invalid strict version format (%s)">
2163
2164=item *
2165
2166L<Invalid version format (%s)|perldiag/"Invalid version format (%s)">
2167
2168=item *
2169
2170L<Invalid version object|perldiag/"Invalid version object">
2171
2172=back
2173
5076a392
FC
2174=head3 L<perlbook>
2175
41e29def 2176L<perlbook> has been expanded to cover many more popular books.
5076a392 2177
41e29def 2178=head3 C<SvTRUE> macro
5076a392 2179
41e29def
FC
2180The documentation for the C<SvTRUE> macro in
2181L<perlapi> was simply wrong in stating that
5076a392
FC
2182get-magic is not processed. It has been corrected.
2183
41e29def 2184=head3 L<perlvar> revamp
5076a392 2185
41e29def 2186L<perlvar> reorders the variables and groups them by topic. Each variable
5076a392 2187introduced after Perl 5.000 notes the first version in which it is
41e29def 2188available. L<perlvar> also has a new section for deprecated variables to
5076a392
FC
2189note when they were removed.
2190
41e29def 2191=head3 Array and hash slices in scalar context
5076a392 2192
41e29def 2193These are now documented in L<perldata>.
5076a392 2194
41e29def 2195=head3 C<use locale> and formats
5076a392
FC
2196
2197L<perlform> and L<perllocale> have been corrected to state that
2198C<use locale> affects formats.
2199
5076a392
FC
2200=head3 L<overload>
2201
5076a392
FC
2202L<overload>'s documentation has practically undergone a rewrite. It
2203is now much more straightforward and clear.
2204
41e29def 2205=head3 L<perlhack> and perlrepository revamp
5076a392
FC
2206
2207The L<perlhack> and perlrepository documents have been heavily edited and
2208split up into several new documents.
2209
2210The L<perlhack> document is now much shorter, and focuses on the Perl 5
2211development process and submitting patches to Perl. The technical content has
2212been moved to several new documents, L<perlsource>, L<perlinterp>,
2213L<perlhacktut>, and L<perlhacktips>. This technical content has only been
2214lightly edited.
2215
2216The perlrepository document has been renamed to L<perlgit>. This new document
2217is just a how-to on using git with the Perl source code. Any other content
2218that used to be in perlrepository has been moved to perlhack.
2219
41e29def 2220=head3 Time::Piece examples
5076a392
FC
2221
2222Examples in L<perlfaq4> have been updated to show the use of
41e29def 2223L<Time::Piece>.
5076a392
FC
2224
2225=head1 Diagnostics
2226
2227The following additions or changes have been made to diagnostic output,
2228including warnings and fatal error messages. For the complete list of
2229diagnostic messages, see L<perldiag>.
2230
2231=head2 New Diagnostics
2232
a593b319
FC
2233=head3 New Errors
2234
5076a392
FC
2235=over
2236
a593b319 2237=item Closure prototype called
5076a392 2238
a593b319
FC
2239This error occurs when a subroutine reference passed to an attribute
2240handler is called, if the subroutine is a closure [perl #68560].
5076a392 2241
a593b319 2242=item Insecure user-defined property %s
5076a392 2243
a593b319
FC
2244Perl detected tainted data when trying to compile a regular
2245expression that contains a call to a user-defined character property
2246function, i.e. C<\p{IsFoo}> or C<\p{InFoo}>.
2247See L<perlunicode/User-Defined Character Properties> and L<perlsec>.
5076a392 2248
a593b319 2249=item panic: gp_free failed to free glob pointer - something is repeatedly re-creating entries
5076a392 2250
a593b319
FC
2251This new error is triggered if a destructor called on an object in a
2252typeglob that is being freed creates a new typeglob entry containing an
2253object with a destructor that creates a new entry containing an object....
5076a392 2254
a593b319 2255=item Parsing code internal error (%s)
5076a392 2256
a593b319
FC
2257This new fatal error is produced when parsing
2258code supplied by an extension violates the
2259parser's API in a detectable way.
5076a392 2260
a593b319 2261=item refcnt: fd %d%s
5076a392 2262
a593b319
FC
2263This new error only occurs if a internal consistency check fails when a
2264pipe is about to be closed.
5076a392 2265
a593b319 2266=item Regexp modifier "/%c" may not appear twice
5076a392 2267
a593b319
FC
2268The regular expression pattern has one of the
2269mutually exclusive modifiers repeated.
5076a392 2270
a593b319 2271=item Regexp modifiers "/%c" and "/%c" are mutually exclusive
5076a392 2272
a593b319
FC
2273The regular expression pattern has more than one of the mutually
2274exclusive modifiers.
5076a392 2275
a593b319 2276=item Using !~ with %s doesn't make sense
5076a392 2277
a593b319 2278This error occurs when C<!~> is used with C<s///r> or C<y///r>.
5076a392 2279
a593b319 2280=back
5076a392 2281
a593b319 2282=head3 New Warnings
5076a392 2283
a593b319 2284=over
5076a392 2285
a593b319 2286=item "\b{" is deprecated; use "\b\{" instead
5076a392 2287
a593b319 2288=item "\B{" is deprecated; use "\B\{" instead
5076a392 2289
a593b319
FC
2290Use of an unescaped "{" immediately following a C<\b> or C<\B> is now
2291deprecated so as to reserve its use for Perl itself in a future release.
5076a392 2292
a593b319 2293=item Operation "%s" returns its argument for ...
5076a392 2294
a593b319
FC
2295Performing an operation requiring Unicode semantics (such as case-folding)
2296on a Unicode surrogate or a non-Unicode character now triggers a warning:
2297'Operation "%s" returns its argument for ...'.
5076a392 2298
a593b319
FC
2299=item Use of qw(...) as parentheses is deprecated
2300
2301See L</"Use of qw(...) as parentheses">, above, for details.
5076a392
FC
2302
2303=back
2304
2305=head2 Changes to Existing Diagnostics
2306
2307=over 4
2308
2309=item *
2310
4ed2cea4
FC
2311The "Variable $foo is not imported" warning that precedes a
2312C<strict 'vars'> error has now been assigned the "misc" category, so that
2313C<no warnings> will suppress it [perl #73712].
2314
2315=item *
2316
5076a392
FC
2317C<warn> and C<die> now produce 'Wide character' warnings when fed a
2318character outside the byte range if STDERR is a byte-sized handle.
2319
2320=item *
2321
2322The 'Layer does not match this perl' error message has been replaced with
a593b319 2323these more helpful messages [perl #73754]:
5076a392
FC
2324
2325=over 4
2326
2327=item *
2328
2329PerlIO layer function table size (%d) does not match size expected by this
2330perl (%d)
2331
2332=item *
2333
2334PerlIO layer instance size (%d) does not match size expected by this perl
2335(%d)
2336
2337=back
2338
5076a392
FC
2339=item *
2340
2341The "Found = in conditional" warning that is emitted when a constant is
2342assigned to a variable in a condition is now withheld if the constant is
2343actually a subroutine or one generated by C<use constant>, since the value
2344of the constant may not be known at the time the program is written
2345[perl #77762].
2346
2347=item *
2348
2349Previously, if none of the C<gethostbyaddr>, C<gethostbyname> and
2350C<gethostent> functions were implemented on a given platform, they would
2351all die with the message 'Unsupported socket function "gethostent" called',
2352with analogous messages for C<getnet*> and C<getserv*>. This has been
2353corrected.
2354
2355=item *
2356
a593b319
FC
2357The warning message about unrecognized regular expression escapes passed
2358through has been changed to include any literal '{' following the
2359two-character escape. E.g., "\q{" is now emitted instead of "\q".
5076a392
FC
2360
2361=back
2362
2363=head1 Utility Changes
2364
0b88cc74 2365=head3 L<perlbug>
5076a392
FC
2366
2367=over 4
2368
2369=item *
2370
0b88cc74
FC
2371L<perlbug> now looks in the EMAIL environment variable for a return address
2372if the REPLY-TO and REPLYTO variables are empty.
5076a392
FC
2373
2374=item *
2375
0b88cc74
FC
2376L<perlbug> did not previously generate a From: header, potentially
2377resulting in dropped mail. Now it does include that header.
5076a392
FC
2378
2379=item *
2380
0b88cc74 2381The user's address is now used as the return-path.
4ed2cea4 2382
0b88cc74
FC
2383Many systems these days don't have a valid Internet domain name and
2384perlbug@perl.org does not accept email with a return-path that does
2385not resolve. So the user's address is now passed to sendmail so it's
2386less likely to get stuck in a mail queue somewhere [perl #82996].
5076a392 2387
2c389f6c
FC
2388=item *
2389
d430b8e7
FC
2390L<perlbug> now always gives the reporter a chance to change the email
2391address it guesses for them (5.12.2).
2392
2393=item *
2394
2395L<perlbug> should no longer warn about uninitialized values when using the C<-d>
2396and C<-v> options (5.12.2).
2c389f6c 2397
5076a392
FC
2398=back
2399
0b88cc74 2400=head3 L<perl5db.pl>
5076a392 2401
0b88cc74 2402=over
5076a392
FC
2403
2404=item *
2405
0b88cc74
FC
2406The remote terminal works after forking and spawns new sessions - one
2407for each forked process.
5076a392
FC
2408
2409=back
2410
0b88cc74 2411=head3 L<ptargrep>
5076a392
FC
2412
2413=over 4
2414
2415=item *
2416
0b88cc74
FC
2417L<ptargrep> is a new utility to apply pattern matching to the contents of
2418files in a tar archive. It comes with C<Archive::Tar>.
5076a392
FC
2419
2420=back
2421
2422=head1 Configuration and Compilation
2423
61752d82
FC
2424See also L</"Naming fixes in Policy_sh.SH may invalidate Policy.sh">,
2425above.
2426
5076a392
FC
2427=over 4
2428
2429=item *
2430
87595b22
FC
2431CCINCDIR and CCLIBDIR for the mingw64
2432cross-compiler are now correctly under
5076a392
FC
2433$(CCHOME)\mingw\include and \lib rather than immediately below $(CCHOME).
2434
5076a392
FC
2435This means the 'incpath', 'libpth', 'ldflags', 'lddlflags' and
2436'ldflags_nolargefiles' values in Config.pm and Config_heavy.pl are now
87595b22 2437set correctly.
5076a392
FC
2438
2439=item *
2440
87595b22
FC
2441'make test.valgrind' has been adjusted to account for cpan/dist/ext
2442separation.
5076a392
FC
2443
2444=item *
2445
2446On compilers that support it, C<-Wwrite-strings> is now added to cflags by
2447default.
2448
2449=item *
2450
2451The C<Encode> module can now (once again) be included in a static Perl
2452build. The special-case handling for this situation got broken in Perl
24535.11.0, and has now been repaired.
2454
1e463951
FC
2455=item *
2456
2457The previous default size of a PerlIO buffer (4096 bytes) has been increased
2458to the larger of 8192 bytes and your local BUFSIZ. Benchmarks show that doubling
2459this decade-old default increases read and write performance in the neighborhood
2460of 25% to 50% when using the default layers of perlio on top of unix. To choose
2461a non-default size, such as to get back the old value or to obtain an even
2462larger value, configure with:
2463
2464 ./Configure -Accflags=-DPERLIOBUF_DEFAULT_BUFSIZ=N
2465
2466where N is the desired size in bytes; it should probably be a multiple of
2467your page size.
2468
d430b8e7
FC
2469=item *
2470
2471An "incompatible operand types" error in ternary expressions when building
2472with C<clang> has been fixed (5.12.2).
2473
2474=item *
2475
2476Perl now skips setuid C<File::Copy> tests on partitions it detects to be mounted
2477as C<nosuid> (5.12.2).
2478
5076a392
FC
2479=back
2480
5076a392
FC
2481=head1 Platform Support
2482
5076a392
FC
2483=head2 New Platforms
2484
5076a392
FC
2485=over 4
2486
2487=item AIX
2488
cdc10f43 2489Perl now builds on AIX 4.2 (5.12.1).
5076a392
FC
2490
2491=back
2492
2493=head2 Discontinued Platforms
2494
2495=over 4
2496
5076a392
FC
2497=item Apollo DomainOS
2498
2499The last vestiges of support for this platform have been excised from the
2500Perl distribution. It was officially discontinued in version 5.12.0. It had
2501not worked for years before that.
2502
2503=item MacOS Classic
2504
2505The last vestiges of support for this platform have been excised from the
2506Perl distribution. It was officially discontinued in an earlier version.
2507
2508=back
2509
2510=head2 Platform-Specific Notes
2511
d430b8e7
FC
2512=head3 AIX
2513
2514=over
2515
2516=item *
2517
2518F<README.aix> has been updated with information about the XL C/C++ V11 compiler
2519suite (5.12.2).
2520
2521=back
2522
2523=head3 ARM
2524
2525=over
2526
2527=item *
2528
2529The C<d_u32align> configuration probe on ARM has been fixed (5.12.2).
2530
2531=back
2532
554003a2 2533=head3 Cygwin
5076a392
FC
2534
2535=over 4
2536
2537=item *
2538
554003a2 2539MakeMaker has been updated to build man pages on cygwin.
5076a392
FC
2540
2541=item *
2542
554003a2
FC
2543Improved rebase behaviour
2544
2545If a dll is updated on cygwin the old imagebase address is reused.
2546This solves most rebase errors, especially when updating on core dll's.
2547See L<http://www.tishler.net/jason/software/rebase/rebase-2.4.2.README> for more information.
5076a392
FC
2548
2549=item *
2550
554003a2 2551Support for the standard cygwin dll prefix, which is e.g. needed for FFI's
5076a392
FC
2552
2553=item *
2554
554003a2 2555Updated build hints file
5076a392
FC
2556
2557=back
2558
cdc10f43
FC
2559=head3 FreeBSD 7
2560
2561=over
2562
2563=item *
2564
2565FreeBSD 7 no longer contains F</usr/bin/objformat>. At build time,
2566Perl now skips the F<objformat> check for versions 7 and higher and
2567assumes ELF (5.12.1).
2568
2569=back
2570
2571=head3 HP-UX
2572
2573=over
2574
2575=item *
2576
2577Perl now allows -Duse64bitint without promoting to use64bitall on HP-UX
2578(5.12.1).
2579
2580=back
2581
554003a2 2582=head3 IRIX
5076a392
FC
2583
2584Conversion of strings to floating-point numbers is now more accurate on
2585IRIX systems [perl #32380].
2586
554003a2 2587=head3 Mac OS X
5076a392
FC
2588
2589Early versions of Mac OS X (Darwin) had buggy implementations of the
2590C<setregid>, C<setreuid>, C<setrgid> and C<setruid> functions, so perl
2591would pretend they did not exist.
2592
2593These functions are now recognised on Mac OS 10.5 (Leopard; Darwin 9) and
2594higher, as they have been fixed [perl #72990].
2595
554003a2 2596=head3 MirBSD
5076a392 2597
554003a2
FC
2598Previously if you built perl with a shared libperl.so on MirBSD (the
2599default config), it would work up to the installation; however, once
2600installed, it would be unable to find libperl. So path handling is now
2601treated as in the other BSD dialects.
5076a392 2602
554003a2 2603=head3 NetBSD
5076a392 2604
554003a2
FC
2605The NetBSD hints file has been changed to make the system's malloc the
2606default.
5076a392 2607
554003a2 2608=head3 Recent OpenBSDs now use perl's malloc
5076a392 2609
554003a2
FC
2610OpenBSD E<gt> 3.7 has a new malloc implementation which is mmap-based
2611and as such can release memory back to the OS; however, perl's use of
2612this malloc causes a substantial slowdown so we now default to using
2613perl's malloc instead [perl #75742].
5076a392 2614
554003a2 2615=head3 OpenVOS
5076a392 2616
554003a2 2617perl now builds again with OpenVOS (formerly known as Stratus VOS)
5a553547 2618[perl #78132] (5.12.3).
5076a392 2619
554003a2 2620=head3 Solaris
5076a392 2621
554003a2 2622DTrace is now supported on Solaris. There used to be build failures, but
5a553547 2623these have been fixed [perl #73630] (5.12.3).
5076a392 2624
554003a2 2625=head3 VMS
5076a392
FC
2626
2627=over
2628
2629=item *
2630
cdc10f43
FC
2631It's now possible to build extensions on older (pre 7.3-2) VMS systems.
2632
2633DCL symbol length was limited to 1K up until about seven years or
2634so ago, but there was no particularly deep reason to prevent those
2635older systems from configuring and building Perl (5.12.1).
2636
2637=item *
2638
2639We fixed the previously-broken C<-Uuseperlio> build on VMS.
2640
2641We were checking a variable that doesn't exist in the non-default
2642case of disabling perlio. Now we only look at it when it exists (5.12.1).
2643
2644=item *
2645
2646We fixed the -Uuseperlio command-line option in configure.com.
2647
2648Formerly it only worked if you went through all the questions
2649interactively and explicitly answered no (5.12.1).
2650
2651=item *
2652
554003a2 2653C<PerlIOUnix_open> now honours the default permissions on VMS.
5076a392 2654
554003a2
FC
2655When C<perlio> became the default and C<unixio> became the default bottom layer,
2656the most common path for creating files from Perl became C<PerlIOUnix_open>,
2657which has always explicitly used C<0666> as the permission mask.
5076a392 2658
554003a2
FC
2659To avoid this, C<0777> is now passed as the permissions to C<open()>. In the
2660VMS CRTL, C<0777> has a special meaning over and above intersecting with the
2661current umask; specifically, it allows Unix syscalls to preserve native default
5a553547
FC
2662permissions (5.12.3).
2663
2664=item *
2665
2666Spurious record boundaries are no longer
2667introduced by the PerlIO layer during output (5.12.3).
5076a392
FC
2668
2669=item *
2670
554003a2
FC
2671The shortening of symbols longer than 31 characters in the C sources is
2672now done by the compiler rather than by xsubpp (which could only do so
2673for generated symbols in XS code).
5076a392
FC
2674
2675=item *
2676
554003a2
FC
2677Record-oriented files (record format variable or variable with fixed control)
2678opened for write by the perlio layer will now be line-buffered to prevent the
2679introduction of spurious line breaks whenever the perlio buffer fills up.
5076a392 2680
d430b8e7
FC
2681=item *
2682
2683F<git_version.h> is now installed on VMS. This was an oversight in v5.12.0 which
2684caused some extensions to fail to build (5.12.2).
2685
2686=item *
2687
2688Several memory leaks in L<stat()|perlfunc/"stat FILEHANDLE"> have been fixed (5.12.2).
2689
2690=item *
2691
2692A memory leak in C<Perl_rename()> due to a double allocation has been
2693fixed (5.12.2).
2694
2695=item *
2696
2697A memory leak in C<vms_fid_to_name()> (used by C<realpath()> and
2698C<realname()>) has been fixed (5.12.2).
2699
5076a392
FC
2700=back
2701
554003a2 2702=head3 Windows
5076a392 2703
5a1f7719
FC
2704See also L</"fork() emulation will not wait for signalled children"> and
2705L</"Perl source code is read in text mode on Windows">, above.
2706
5076a392
FC
2707=over 4
2708
2709=item *
2710
554003a2 2711Fixed build process for SDK2003SP1 compilers.
5076a392 2712
554003a2 2713=item *
5076a392 2714
01b1a9e4
FC
2715Compilation with Visual Studio 2010 is now supported.
2716
2717=item *
2718
554003a2
FC
2719When using old 32-bit compilers, the define C<_USE_32BIT_TIME_T> will now
2720be set in C<$Config{ccflags}>. This improves portability when compiling
2721XS extensions using new compilers, but for a perl compiled with old 32-bit
2722compilers.
5076a392
FC
2723
2724=item *
2725
554003a2
FC
2726C<$Config{gccversion}> is now set correctly when perl is built using the
2727mingw64 compiler from L<http://mingw64.org> [perl #73754].
5076a392 2728
554003a2
FC
2729=item *
2730
d430b8e7
FC
2731When building Perl with the mingw64 x64 cross-compiler C<incpath>,
2732C<libpth>, C<ldflags>, C<lddlflags> and C<ldflags_nolargefiles> values
2733in F<Config.pm> and F<Config_heavy.pl> were not previously being set
2734correctly because, with that compiler, the include and lib directories
2735are not immediately below C<$(CCHOME)> (5.12.2).
2736
2737=item *
2738
554003a2
FC
2739The build process proceeds more smoothly with mingw and dmake when
2740F<C:\MSYS\bin> is in the PATH, due to a C<Cwd> fix.
5076a392
FC
2741
2742=item *
2743
554003a2
FC
2744Support for building with Visual C++ 2010 is now underway, but is not yet
2745complete. See F<README.win32> or L<perlwin32> for more details.
5076a392 2746
554003a2
FC
2747=item *
2748
2749The option to use an externally-supplied C<crypt()>, or to build with no
2750C<crypt()> at all, has been removed. Perl supplies its own C<crypt()>
2751implementation for Windows, and the political situation that required
2752this part of the distribution to sometimes be omitted is long gone.
5076a392
FC
2753
2754=back
2755
2756=head1 Internal Changes
2757
1e463951 2758=head2 New APIs
5076a392 2759
1e463951 2760=head3 CLONE_PARAMS structure added to ease correct thread creation
5076a392 2761
1e463951
FC
2762Modules that create threads should now create C<CLONE_PARAMS> structures
2763by calling the new function C<Perl_clone_params_new()>, and free them with
2764C<Perl_clone_params_del()>. This will ensure compatibility with any future
2765changes to the internals of the C<CLONE_PARAMS> structure layout, and that
2766it is correctly allocated and initialised.
5076a392 2767
1e463951 2768=head3 New parsing functions
5076a392 2769
1e463951
FC
2770Several functions have been added for parsing statements or multiple
2771statements:
5076a392 2772
1e463951 2773=over
5076a392
FC
2774
2775=item *
2776
1e463951 2777C<parse_fullstmt> parses a complete Perl statement.
5076a392
FC
2778
2779=item *
2780
1e463951
FC
2781C<parse_stmtseq> parses a sequence of statements, up
2782to closing brace or EOF.
5076a392
FC
2783
2784=item *
2785
1e463951 2786C<parse_block> parses a block [perl #78222].
5076a392
FC
2787
2788=item *
2789
1e463951
FC
2790C<parse_barestmt> parses a statement
2791without a label.
5076a392
FC
2792
2793=item *
2794
1e463951 2795C<parse_label> parses a statement label, separate from statements.
5076a392 2796
1e463951 2797=back
5076a392 2798
1e463951
FC
2799The
2800L<C<parse_fullexpr()>|perlapi/parse_fullexpr>,
2801L<C<parse_listexpr()>|perlapi/parse_listexpr>,
2802L<C<parse_termexpr()>|perlapi/parse_termexpr>, and
2803L<C<parse_arithexpr()>|perlapi/parse_arithexpr>
2804functions have been added to the API. They perform
2805recursive-descent parsing of expressions at various precedence levels.
2806They are expected to be used by syntax plugins.
5076a392 2807
1e463951 2808See L<perlapi> for details.
5076a392 2809
1e463951 2810=head3 Hints hash API
5076a392 2811
1e463951
FC
2812A new C API for introspecting the hinthash C<%^H> at runtime has been
2813added. See C<cop_hints_2hv>, C<cop_hints_fetchpvn>, C<cop_hints_fetchpvs>,
2814C<cop_hints_fetchsv>, and C<hv_copy_hints_hv> in L<perlapi> for details.
5076a392 2815
1e463951
FC
2816A new, experimental API has been added for accessing the internal
2817structure that Perl uses for C<%^H>. See the functions beginning with
2818C<cophh_> in L<perlapi>.
5076a392 2819
1e463951 2820=head3 C interface to C<caller()>
5076a392 2821
1e463951
FC
2822The C<caller_cx> function has been added as an XSUB-writer's equivalent of
2823C<caller()>. See L<perlapi> for details.
5076a392 2824
1e463951 2825=head3 Custom per-subroutine check hooks
5076a392 2826
1e463951
FC
2827XS code in an extension module can now annotate a subroutine (whether
2828implemented in XS or in Perl) so that nominated XS code will be called
2829at compile time (specifically as part of op checking) to change the op
2830tree of that subroutine. The compile-time check function (supplied by
2831the extension module) can implement argument processing that can't be
2832expressed as a prototype, generate customised compile-time warnings,
2833perform constant folding for a pure function, inline a subroutine
2834consisting of sufficiently simple ops, replace the whole call with a
2835custom op, and so on. This was previously all possible by hooking the
2836C<entersub> op checker, but the new mechanism makes it easy to tie the
2837hook to a specific subroutine. See L<perlapi/cv_set_call_checker>.
5076a392 2838
1e463951
FC
2839To help in writing custom check hooks, several subtasks within standard
2840C<entersub> op checking have been separated out and exposed in the API.
5076a392 2841
1e463951 2842=head3 Improved support for custom OPs
5076a392 2843
1e463951
FC
2844Custom ops can now be registered with the new C<custom_op_register> C
2845function and the C<XOP> structure. This will make it easier to add new
2846properties of custom ops in the future. Two new properties have been added
2847already, C<xop_class> and C<xop_peep>.
5076a392 2848
1e463951
FC
2849C<xop_class> is one of the OA_*OP constants, and allows L<B> and other
2850introspection mechanisms to work with custom ops
2851that aren't BASEOPs. C<xop_peep> is a pointer to
2852a function that will be called for ops of this
2853type from C<Perl_rpeep>.
5076a392 2854
1e463951
FC
2855See L<perlguts/Custom Operators> and L<perlapi/Custom Operators> for more
2856detail.
5076a392 2857
1e463951
FC
2858The old C<PL_custom_op_names>/C<PL_custom_op_descs> interface is still
2859supported but discouraged.
5076a392 2860
1e463951 2861=head3 Scope hooks
5076a392 2862
1e463951
FC
2863It is now possible for XS code to hook into Perl's lexical scope
2864mechanism at compile time, using the new C<Perl_blockhook_register>
2865function. See L<perlguts/"Compile-time scope hooks">.
5076a392 2866
1e463951 2867=head3 The recursive part of the peephole optimizer is now hookable
5076a392
FC
2868
2869In addition to C<PL_peepp>, for hooking into the toplevel peephole optimizer, a
2870C<PL_rpeepp> is now available to hook into the optimizer recursing into
2871side-chains of the optree.
2872
1e463951 2873=head3 New non-magical variants of existing functions
5076a392 2874
1e463951
FC
2875The following functions/macros have been added to the API. The C<*_nomg>
2876macros are equivalent to their non-_nomg variants, except that they ignore
2877get-magic. Those ending in C<_flags> allow one to specify whether
2878get-magic is processed.
5076a392 2879
1e463951
FC
2880 sv_2bool_flags
2881 SvTRUE_nomg
2882 sv_2nv_flags
2883 SvNV_nomg
2884 sv_cmp_flags
2885 sv_cmp_locale_flags
2886 sv_eq_flags
2887 sv_collxfrm_flags
5076a392 2888
1e463951 2889In some of these cases, the non-_flags functions have
5076a392
FC
2890been replaced with wrappers around the new functions.
2891
1e463951 2892=head3 pv/pvs/sv versions of existing functions
5076a392 2893
1e463951 2894Many functions ending with pvn now have equivalent pv/pvs/sv versions.
5076a392 2895
1e463951 2896=head3 List op-building functions
5076a392 2897
1e463951
FC
2898List op-building functions have been added to the
2899API. See L<op_append_elem|perlapi/op_append_elem>,
2900L<op_append_list|perlapi/op_append_list>, and
2901L<op_prepend_elem|perlapi/op_prepend_elem> in L<perlapi>.
5076a392 2902
1e463951 2903=head3 C<LINKLIST>
5076a392 2904
1e463951
FC
2905The L<LINKLIST|perlapi/LINKLIST> macro, part of op building that
2906constructs the execution-order op chain, has been added to the API.
5076a392 2907
1e463951 2908=head3 Localisation functions
5076a392 2909
1e463951
FC
2910The C<save_freeop>, C<save_op>, C<save_pushi32ptr> and C<save_pushptrptr>
2911functions have been added to the API.
5076a392 2912
1e463951 2913=head3 Stash names
5076a392 2914
1e463951
FC
2915A stash can now have a list of effective names in addition to its usual
2916name. The first effective name can be accessed via the C<HvENAME> macro,
2917which is now the recommended name to use in MRO linearisations (C<HvNAME>
2918being a fallback if there is no C<HvENAME>).
5076a392 2919
1e463951
FC
2920These names are added and deleted via C<hv_ename_add> and
2921C<hv_ename_delete>. These two functions are I<not> part of the API.
5076a392 2922
1e463951 2923=head3 New functions for finding and removing magic
5076a392 2924
1e463951
FC
2925The L<C<mg_findext()>|perlapi/mg_findext> and
2926L<C<sv_unmagicext()>|perlapi/sv_unmagicext>
2927functions have been added to the API.
2928They allow extension authors to find and remove magic attached to
2929scalars based on both the magic type and the magic virtual table, similar to how
2930C<sv_magicext()> attaches magic of a certain type and with a given virtual table
2931to a scalar. This eliminates the need for extensions to walk the list of
2932C<MAGIC> pointers of an C<SV> to find the magic that belongs to them.
5076a392 2933
1e463951 2934=head3 C<find_rundefsv>
5076a392 2935
1e463951
FC
2936This function returns the SV representing C<$_>, whether it's lexical
2937or dynamic.
5076a392 2938
1e463951 2939=head3 C<Perl_croak_no_modify>
5076a392 2940
1e463951
FC
2941C<Perl_croak_no_modify()> is short-hand for
2942C<Perl_croak("%s", PL_no_modify)>.
5076a392 2943
1e463951 2944=head3 C<PERL_STATIC_INLINE> define
5076a392 2945
1e463951
FC
2946The C<PERL_STATIC_INLINE> define has been added to provide the best-guess
2947incantation to use for static inline functions, if the C compiler supports
2948C99-style static inline. If it doesn't, it'll give a plain C<static>.
5076a392 2949
1e463951
FC
2950C<HAS_STATIC_INLINE> can be used to check if the compiler actually supports
2951inline functions.
5076a392 2952
1e463951 2953=head3 New C<pv_escape> option for hexadecimal escapes
5076a392 2954
1e463951
FC
2955A new option, C<PERL_PV_ESCAPE_NONASCII>, has been added to C<pv_escape> to
2956dump all characters above ASCII in hexadecimal. Before, one could get all
2957characters as hexadecimal or the Latin1 non-ASCII as octal.
5076a392 2958
1e463951 2959=head3 C<lex_start>
5076a392 2960
1e463951 2961C<lex_start> has been added to the API, but is considered experimental.
5076a392 2962
1e463951 2963=head3 C<op_scope()> and C<op_lvalue()>
5076a392 2964
1e463951
FC
2965The C<op_scope()> and C<op_lvalue()> functions have been added to the API,
2966but are considered experimental.
5076a392 2967
1e463951 2968=head2 C API Changes
5076a392 2969
1e463951 2970=head3 C<PERL_POLLUTE> has been removed
5076a392 2971
1e463951
FC
2972The option to define C<PERL_POLLUTE> to expose older 5.005 symbols for
2973backwards compatibility has been removed. It's use was always discouraged,
2974and MakeMaker contains a more specific escape hatch:
5076a392 2975
1e463951 2976 perl Makefile.PL POLLUTE=1
5076a392 2977
1e463951
FC
2978This can be used for modules that have not been upgraded to 5.6 naming
2979conventions (and really should be completely obsolete by now).
5076a392 2980
1e463951 2981=head3 Check API compatibility when loading XS modules
5076a392 2982
1e463951
FC
2983When perl's API changes in incompatible ways (which usually happens between
2984major releases), XS modules compiled for previous versions of perl will not
2985work anymore. They will need to be recompiled against the new perl.
5076a392 2986
1e463951
FC
2987In order to ensure that modules are recompiled, and to prevent users from
2988accidentally loading modules compiled for old perls into newer ones, the
2989C<XS_APIVERSION_BOOTCHECK> macro has been added. That macro, which is
2990called when loading every newly compiled extension, compares the API
2991version of the running perl with the version a module has been compiled for
2992and raises an exception if they don't match.
5076a392 2993
1e463951 2994=head3 Perl_fetch_cop_label
5076a392 2995
1e463951
FC
2996The first argument of the C API function C<Perl_fetch_cop_label> has changed
2997from C<struct refcounted he *> to C<COP *>, to insulate the user from
2998implementation details.
5076a392 2999
1e463951
FC
3000This API function was marked as "may change", and likely isn't in use outside
3001the core. (Neither an unpacked CPAN, nor Google's codesearch, finds any other
3002references to it.)
5076a392 3003
1e463951 3004=head3 GvCV() and GvGP() are no longer lvalues
5076a392 3005
1e463951
FC
3006The new GvCV_set() and GvGP_set() macros are now provided to replace
3007assignment to those two macros.
5076a392 3008
1e463951
FC
3009This allows a future commit to eliminate some backref magic between GV
3010and CVs, which will require complete control over assignment to the
3011gp_cv slot.
5076a392 3012
1e463951 3013=head3 CvGV() is no longer an lvalue
5076a392 3014
1e463951
FC
3015Under some circumstances, the C<CvGV()> field of a CV is now
3016reference-counted. To ensure consistent behaviour, direct assignment to
3017it, for example C<CvGV(cv) = gv> is now a compile-time error. A new macro,
3018C<CvGV_set(cv,gv)> has been introduced to perform this operation
3019safely. Note that modification of this field is not part of the public
3020API, regardless of this new macro (and despite its being listed in this section).
5076a392 3021
1e463951 3022=head3 CvSTASH() is no longer an lvalue
5076a392 3023
1e463951
FC
3024The C<CvSTASH()> macro can now only be used as an rvalue. C<CvSTASH_set()>
3025has been added to replace assignment to C<CvSTASH()>. This is to ensure
3026that backreferences are handled properly. These macros are not part of the
3027API.
5076a392 3028
1e463951 3029=head3 Calling conventions for C<newFOROP> and C<newWHILEOP>
5076a392 3030
1e463951
FC
3031The way the parser handles labels has been cleaned up and refactored. As a
3032result, the C<newFOROP()> constructor function no longer takes a parameter
3033stating what label is to go in the state op.
5076a392 3034
1e463951
FC
3035The C<newWHILEOP()> and C<newFOROP()> functions no longer accept a line
3036number as a parameter.
5076a392 3037
1e463951 3038=head3 Flags passed to C<uvuni_to_utf8_flags> and C<utf8n_to_uvuni>
5076a392 3039
1e463951
FC
3040Some of the flags parameters to uvuni_to_utf8_flags() and
3041utf8n_to_uvuni() have changed. This is a result of Perl's now allowing
5076a392
FC
3042internal storage and manipulation of code points that are problematic
3043in some situations. Hence, the default actions for these functions has
3044been complemented to allow these code points. The new flags are
3045documented in L<perlapi>. Code that requires the problematic code
483b16f3 3046points to be rejected needs to change to use the new flags. Some flag
5076a392
FC
3047names are retained for backward source compatibility, though they do
3048nothing, as they are now the default. However the flags
3049C<UNICODE_ALLOW_FDD0>, C<UNICODE_ALLOW_FFFF>, C<UNICODE_ILLEGAL>, and
3050C<UNICODE_IS_ILLEGAL> have been removed, as they stem from a
3051fundamentally broken model of how the Unicode non-character code points
3052should be handled, which is now described in
3053L<perlunicode/Non-character code points>. See also L</Selected Bug Fixes>.
3054
1e463951 3055XXX Which bugs in particular? Selected Bug Fixes is too long for this link
483b16f3
KW
3056to be meaningful right now
3057I don't see the bugs in that section currently -- khw
5076a392 3058
1e463951 3059=head2 Deprecated C APIs
5076a392 3060
1e463951 3061=over
5076a392 3062
1e463951 3063=item C<Perl_ptr_table_clear>
5076a392 3064
1e463951
FC
3065C<Perl_ptr_table_clear> is no longer part of Perl's public API. Calling it
3066now generates a deprecation warning, and it will be removed in a future
3067release.
5076a392 3068
1e463951 3069=item C<sv_compile_2op>
5076a392 3070
1e463951
FC
3071The C<sv_compile_2op()> API function is now deprecated. Searches suggest
3072that nothing on CPAN is using it, so this should have zero impact.
5076a392 3073
1e463951
FC
3074It attempted to provide an API to compile code down to an optree, but failed
3075to bind correctly to lexicals in the enclosing scope. It's not possible to
3076fix this problem within the constraints of its parameters and return value.
5076a392 3077
1e463951 3078=item C<find_rundefsvoffset>
5076a392 3079
1e463951
FC
3080The C<find_rundefsvoffset> function has been deprecated. It appeared that
3081its design was insufficient for reliably getting the lexical C<$_> at
3082run-time.
5076a392 3083
1e463951
FC
3084Use the new C<find_rundefsv> function or the C<UNDERBAR> macro
3085instead. They directly return the right SV representing C<$_>, whether it's
3086lexical or dynamic.
5076a392 3087
1e463951 3088=item C<CALL_FPTR> and C<CPERLscope>
5076a392 3089
1e463951
FC
3090Those are left from an old implementation of C<MULTIPLICITY> using C++ objects,
3091which was removed in Perl 5.8. Nowadays these macros do exactly nothing, so
3092they shouldn't be used anymore.
5076a392 3093
1e463951
FC
3094For compatibility, they are still defined for external C<XS> code. Only
3095extensions defining C<PERL_CORE> must be updated now.
5076a392 3096
1e463951 3097=back
5076a392 3098
1e463951 3099=head2 Other Internal Changes
5076a392 3100
1e463951 3101=head3 Stack unwinding
5076a392 3102
1e463951
FC
3103The protocol for unwinding the C stack at the last stage of a C<die>
3104has changed how it identifies the target stack frame. This now uses
3105a separate variable C<PL_restartjmpenv>, where previously it relied on
3106the C<blk_eval.cur_top_env> pointer in the C<eval> context frame that
3107has nominally just been discarded. This change means that code running
3108during various stages of Perl-level unwinding no longer needs to take
3109care to avoid destroying the ghost frame.
5076a392 3110
1e463951 3111=head3 Scope stack entries
5076a392 3112
1e463951
FC
3113The format of entries on the scope stack has been changed, resulting in a
3114reduction of memory usage of about 10%. In particular, the memory used by
3115the scope stack to record each active lexical variable has been halved.
5076a392 3116
1e463951 3117=head3 Memory allocation for pointer tables
5076a392 3118
1e463951
FC
3119Memory allocation for pointer tables has been changed. Previously
3120C<Perl_ptr_table_store> allocated memory from the same arena system as
3121C<SV> bodies and C<HE>s, with freed memory remaining bound to those arenas
3122until interpreter exit. Now it allocates memory from arenas private to the
3123specific pointer table, and that memory is returned to the system when
3124C<Perl_ptr_table_free> is called. Additionally, allocation and release are
3125both less CPU intensive.
5076a392 3126
1e463951 3127=head3 C<UNDERBAR>
5076a392 3128
1e463951
FC
3129The C<UNDERBAR> macro now calls C<find_rundefsv>. C<dUNDERBAR> is now a
3130noop but should still be used to ensure past and future compatibility.
5076a392 3131
1e463951 3132=head3 String comparison routines renamed
5076a392 3133
1e463951
FC
3134The ibcmp_* functions have been renamed and are now called foldEQ,
3135foldEQ_locale and foldEQ_utf8. The old names are still available as
3136macros.
3137
3138=head3 C<chop> and C<chomp> implementations merged
3139
3140The opcode bodies for C<chop> and C<chomp> and for C<schop> and C<schomp>
3141have been merged. The implementation functions C<Perl_do_chop()> and
3142C<Perl_do_chomp()>, never part of the public API, have been merged and
3143moved to a static function in F<pp.c>. This shrinks the perl binary
3144slightly, and should not affect any code outside the core (unless it is
3145relying on the order of side effects when C<chomp> is passed a I<list> of
3146values).
5076a392
FC
3147
3148=head1 Selected Bug Fixes
3149
e8e35311
FC
3150=head2 I/O
3151
5076a392
FC
3152=over 4
3153
3154=item *
3155
e8e35311 3156Perl no longer produces this warning:
a593b319
FC
3157
3158 $ perl -we 'open my $f, ">", \my $x; binmode $f, "scalar"'
3159 Use of uninitialized value in binmode at -e line 1.
3160
3161=item *
3162
e8e35311
FC
3163Opening a glob reference via C<< open $fh, "E<gt>", \*glob >> will no longer
3164cause the glob to be corrupted when the filehandle is printed to. This would
3165cause perl to crash whenever the glob's contents were accessed
3166[perl #77492].
4ed2cea4
FC
3167
3168=item *
3169
e8e35311
FC
3170PerlIO no longer crashes when called recursively, e.g., from a signal
3171handler. Now it just leaks memory [perl #75556].
4ed2cea4
FC
3172
3173=item *
3174
e8e35311
FC
3175Most I/O functions were not warning for unopened handles unless the
3176'closed' and 'unopened' warnings categories were both enabled. Now only
3177C<use warnings 'unopened'> is necessary to trigger these warnings (as was
438c239f 3178always meant to be the case).
4ed2cea4
FC
3179
3180=item *
3181
438c239f 3182There have been several fixes to PerlIO layers:
e8e35311 3183
438c239f
FC
3184When C<binmode FH, ":crlf"> pushes the C<:crlf> layer on top of the stack,
3185it no longer enables crlf layers lower in the stack, to avoid unexpected
3186results [perl #38456].
4ed2cea4 3187
438c239f
FC
3188Opening a file in C<:raw> mode now does what it advertises to do (first
3189open the file, then binmode it), instead of simply leaving off the top
3190layer [perl #80764].
5076a392 3191
438c239f
FC
3192The three layers C<:pop>, C<:utf8> and C<:bytes> didn't allow stacking when
3193opening a file. For example
e8e35311 3194this:
5076a392 3195
e8e35311 3196 open FH, '>:pop:perlio', 'some.file' or die $!;
5076a392 3197
438c239f
FC
3198Would throw an error: "Invalid argument". This has been fixed in this
3199release [perl #82484].
5076a392 3200
e8e35311
FC
3201=back
3202
3203=head2 Regular Expression Bug Fixes
3204
3205=over
5076a392
FC
3206
3207=item *
3208
e8e35311
FC
3209The regular expression engine no longer loops when matching
3210C<"\N{LATIN SMALL LIGATURE FF}" =~ /f+/i> and similar expressions
cdc10f43 3211[perl #72998] (5.12.1).
5076a392
FC
3212
3213=item *
3214
e8e35311
FC
3215The trie runtime code should no longer allocate massive amounts of memory,
3216fixing #74484.
5076a392
FC
3217
3218=item *
3219
438c239f
FC
3220Syntax errors in C<< (?{...}) >> blocks no longer cause panic messages
3221[perl #2353].
5076a392
FC
3222
3223=item *
3224
438c239f
FC
3225A pattern like C<(?:(o){2})?> no longer causes a "panic" error
3226[perl #39233].
5076a392
FC
3227
3228=item *
3229
438c239f 3230A fatal error in regular expressions containing C<(.*?)> when processing
d430b8e7 3231UTF-8 data has been fixed [perl #75680] (5.12.2).
5076a392
FC
3232
3233=item *
3234
e8e35311 3235An erroneous regular expression engine optimisation that caused regex verbs like
438c239f 3236C<*COMMIT> sometimes to be ignored has been removed.
5076a392
FC
3237
3238=item *
3239
e8e35311
FC
3240The regular expression bracketed character class C<[\8\9]> was effectively the
3241same as C<[89\000]>, incorrectly matching a NULL character. It also gave
3242incorrect warnings that the C<8> and C<9> were ignored. Now C<[\8\9]> is the
3243same as C<[89]> and gives legitimate warnings that C<\8> and C<\9> are
3244unrecognized escape sequences, passed-through.
5076a392
FC
3245
3246=item *
3247
e8e35311
FC
3248A regular expression match in the right-hand side of a global substitution
3249(C<s///g>) that is in the same scope will no longer cause match variables
3250to have the wrong values on subsequent iterations. This can happen when an
3251array or hash subscript is interpolated in the right-hand side, as in
3252C<s|(.)|@a{ print($1), /./ }|g> [perl #19078].
5076a392
FC
3253
3254=item *
3255
438c239f
FC
3256Several cases in which characters in the Latin-1 non-ASCII range (0x80 to
32570xFF) used not to match themselves or used to match both a character class
3258and its complement have been fixed. For instance, U+00E2 could match both
3259C<\w> and C<\W> [perl #78464] [perl #18281] [perl #60156].
5076a392
FC
3260
3261=item *
3262
e8e35311
FC
3263Matching a Unicode character against an alternation containing characters
3264that happened to match continuation bytes in the former's UTF8
3265representation (C<qq{\x{30ab}} =~ /\xab|\xa9/>) would cause erroneous
3266warnings [perl #70998].
5076a392
FC
3267
3268=item *
3269
e8e35311
FC
3270The trie optimisation was not taking empty groups into account, preventing
3271'foo' from matching C</\A(?:(?:)foo|bar|zot)\z/> [perl #78356].
5076a392
FC
3272
3273=item *
3274
e8e35311
FC
3275A pattern containing a C<+> inside a lookahead would sometimes cause an
3276incorrect match failure in a global match (e.g., C</(?=(\S+))/g>)
3277[perl #68564].
5076a392
FC
3278
3279=item *
3280
e8e35311
FC
3281A regular expression optimisation would sometimes cause a match with a
3282C<{n,m}> quantifier to fail when it should match [perl #79152].
5076a392
FC
3283
3284=item *
3285
e8e35311 3286Case insensitive matching in regular expressions compiled under C<use
438c239f
FC
3287locale> now works much more sanely when the pattern or
3288target string is encoded internally in
3289UTF8. Previously, under these conditions the localeness
e8e35311
FC
3290was completely lost. Now, code points above 255 are treated as Unicode,
3291but code points between 0 and 255 are treated using the current locale
438c239f
FC
3292rules, regardless of whether the pattern or the string is encoded in UTF8.
3293The few case-insensitive matches that cross the 255/256 boundary are not
e8e35311
FC
3294allowed. For example, 0xFF does not caselessly match the character at
32950x178, LATIN CAPITAL LETTER Y WITH DIAERESIS, because 0xFF may not be
3296LATIN SMALL LETTER Y in the current locale, and Perl has no way of
3297knowing if that character even exists in the locale, much less what code
3298point it is.
5076a392
FC
3299
3300=item *
3301
e8e35311
FC
3302The C<(?|...)> regular expression construct no longer crashes if the final
3303branch has more sets of capturing parentheses than any other branch. This
3304was fixed in Perl 5.10.1 for the case of a single branch, but that fix did
3305not take multiple branches into account [perl #84746].
5076a392
FC
3306
3307=item *
3308
e8e35311
FC
3309A bug has been fixed in the implementation of C<{...}> quantifiers in
3310regular expressions that prevented the code block in
3311C</((\w+)(?{ print $2 })){2}/> from seeing the C<$2> sometimes
3312[perl #84294].
5076a392 3313
e8e35311 3314=back
5076a392 3315
e8e35311
FC
3316=head2 Syntax/Parsing Bugs
3317
3318=over
5076a392
FC
3319
3320=item *
3321
e8e35311 3322C<when(scalar){...}> no longer crashes, but produces a syntax error
cdc10f43 3323[perl #74114] (5.12.1).
5076a392
FC
3324
3325=item *
3326
e8e35311
FC
3327A label right before a string eval (C<foo: eval $string>) no longer causes
3328the label to be associated also with the first statement inside the eval
3329[perl #74290] (5.12.1).
5076a392
FC
3330
3331=item *
3332
b2c076b5 3333The C<no 5.13.2;> form of C<no> no longer tries to turn on features or
d430b8e7 3334pragmata (i.e., strict) [perl #70075] (5.12.2).
5076a392
FC
3335
3336=item *
3337
b2c076b5
FC
3338C<BEGIN {require 5.12.0}> now behaves as documented, rather than behaving
3339identically to C<use 5.12.0;>. Previously, C<require> in a C<BEGIN> block
3340was erroneously executing the C<use feature ':5.12.0'> and
3341C<use strict;> behaviour, which only C<use> was documented to
3342provide [perl #69050].
5076a392
FC
3343
3344=item *
3345
5076a392
FC
3346A regression introduced in Perl 5.12.0, making
3347C<< my $x = 3; $x = length(undef) >> result in C<$x> set to C<3> has been
d430b8e7 3348fixed. C<$x> will now be C<undef> [perl #85508] (5.12.2).
b2c076b5
FC
3349
3350=item *
3351
3352When strict 'refs' mode is off, C<%{...}> in rvalue context returns
3353C<undef> if its argument is undefined. An optimisation introduced in perl
33545.12.0 to make C<keys %{...}> faster when used as a boolean did not take
3355this into account, causing C<keys %{+undef}> (and C<keys %$foo> when
3356C<$foo> is undefined) to be an error, which it should only be in strict
3357mode [perl #81750].
5076a392
FC
3358
3359=item *
3360
e8e35311 3361Constant-folding used to cause
5076a392 3362
e8e35311 3363 $text =~ ( 1 ? /phoo/ : /bear/)
5076a392 3364
e8e35311
FC
3365to turn into
3366
3367 $text =~ /phoo/
3368
3369at compile time. Now it correctly matches against C<$_> [perl #20444].
5076a392
FC
3370
3371=item *
3372
e8e35311
FC
3373Parsing Perl code (either with string C<eval> or by loading modules) from
3374within a C<UNITCHECK> block no longer causes the interpreter to crash
3375[perl #70614].
5076a392
FC
3376
3377=item *
3378
b2c076b5
FC
3379String evals no longer fail after 2 billion scopes have been
3380compiled [perl #83364].
3381
3382=item *
3383
e8e35311
FC
3384The parser no longer hangs when encountering certain Unicode characters,
3385such as U+387 [perl #74022].
5076a392
FC
3386
3387=item *
3388
b2c076b5
FC
3389Several contexts no longer allow a Unicode character to begin a word
3390that should never begin words, for an example an accent that must follow
3391another character previously could precede all other characters.
5076a392
FC
3392
3393=item *
3394
e8e35311
FC
3395Defining a constant with the same name as one of perl's special blocks
3396(e.g., INIT) stopped working in 5.12.0, but has now been fixed
3397[perl #78634].
5076a392
FC
3398
3399=item *
3400
e8e35311
FC
3401A reference to a literal value used as a hash key (C<$hash{\"foo"}>) used
3402to be stringified, even if the hash was tied [perl #79178].
5076a392
FC
3403
3404=item *
3405
e8e35311
FC
3406A closure containing an C<if> statement followed by a constant or variable
3407is no longer treated as a constant [perl #63540].
5076a392
FC
3408
3409=item *
3410
e8e35311
FC
3411C<state> can now be used with attributes. It used to mean the same thing as
3412C<my> if attributes were present [perl #68658].
5076a392
FC
3413
3414=item *
3415
e8e35311
FC
3416Expressions like C<< @$a > 3 >> no longer cause C<$a> to be mentioned in
3417the "Use of uninitialized value in numeric gt" warning when C<$a> is
3418undefined (since it is not part of the C<E<gt>> expression, but the operand
3419of the C<@>) [perl #72090].
5076a392
FC
3420
3421=item *
3422
e8e35311
FC
3423Accessing an element of a package array with a hard-coded number (as
3424opposed to an arbitrary expression) would crash if the array did not exist.
3425Usually the array would be autovivified during compilation, but typeglob
3426manipulation could remove it, as in these two cases which used to crash:
5076a392 3427
e8e35311
FC
3428 *d = *a; print $d[0];
3429 undef *d; print $d[0];
5076a392 3430
2c389f6c
FC
3431=item *
3432
3433The C<-C> command line option, when used on the shebang line, can now be
3434followed by other options [perl #72434].
3435
3436=item *
3437
3438The C<B> module was returning C<B::OP>s instead of C<B::LOGOP>s for C<entertry> [perl #80622].
3439This was due to a bug in the perl core, not in C<B> itself.
3440
e8e35311 3441=back
5076a392 3442
e262cb24
FC
3443=head2 Stashes, Globs and Method Lookup
3444
3445Perl 5.10.0 introduced a new internal mechanism for caching MROs (method
3446resolution orders, or lists of parent classes; aka "isa" caches) to make
3447method lookup faster (so @ISA arrays would not have to be searched
3448repeatedly). Unfortunately, this brought with it quite a few bugs. Almost
3449all of these have been fixed now, along with a few MRO-related bugs that
3450existed before 5.10.0:
3451
3452=over
3453
3454=item *
3455
3456The following used to have erratic effects on method resolution, because
3457the "isa" caches were not reset or otherwise ended up listing the wrong
3458classes. These have been fixed.
3459
3460=over
3461
3462=item Aliasing packages by assigning to globs [perl #77358]
3463
3464=item Deleting packages by deleting their containing stash elements
3465
3466=item Undefining the glob containing a package (C<undef *Foo::>)
3467
3468=item Undefining an ISA glob (C<undef *Foo::ISA>)
3469
3470=item Deleting an ISA stash element (C<delete $Foo::{ISA}>)
3471
3472=item Sharing @ISA arrays between classes (via C<*Foo::ISA = \@Bar::ISA> or
3473C<*Foo::ISA = *Bar::ISA>) [perl #77238]
3474
3475=back
3476
3477C<undef *Foo::ISA> would even stop a new C<@Foo::ISA> array from updating
3478caches.
3479
3480=item *
3481
3482Typeglob assignments would crash if the glob's stash no longer existed, so
3483long as the glob assigned to was named 'ISA' or the glob on either side of
3484the assignment contained a subroutine.
3485
3486=item *
3487
3488C<PL_isarev>, which is accessible to Perl via C<mro::get_isarev> is now
3489updated properly when packages are deleted or removed from the C<@ISA> of
3490other classes. This allows many packages to be created and deleted without
3491causing a memory leak [perl #75176].
3492
3493=back
3494
3495In addition, various other bugs related to typeglobs and stashes have been
3496fixed:
5076a392 3497
e8e35311 3498=over
5076a392
FC
3499
3500=item *
3501
e8e35311 3502Some work has been done on the internal pointers that link between symbol
e262cb24 3503tables (stashes), typeglobs and subroutines. This has the effect that
e8e35311
FC
3504various edge cases related to deleting stashes or stash entries (e.g.
3505<%FOO:: = ()>), and complex typeglob or code reference aliasing, will no
3506longer crash the interpreter.
5076a392
FC
3507
3508=item *
3509
e262cb24
FC
3510Assigning a reference to a glob copy now assigns to a glob slot instead of
3511overwriting the glob with a scalar [perl #1804] [perl #77508].
5076a392
FC
3512
3513=item *
3514
e8e35311
FC
3515A bug when replacing the glob of a loop variable within the loop has been fixed
3516[perl #21469]. This
3517means the following code will no longer crash:
5076a392 3518
e8e35311
FC
3519 for $x (...) {
3520 *x = *y;
3521 }
5076a392
FC
3522
3523=item *
3524
3525Assigning a glob to a PVLV used to convert it to a plain string. Now it
3526works correctly, and a PVLV can hold a glob. This would happen when a
3527nonexistent hash or array element was passed to a subroutine:
3528
3529 sub { $_[0] = *foo }->($hash{key});
3530 # $_[0] would have been the string "*main::foo"
3531
3532It also happened when a glob was assigned to, or returned from, an element
3533of a tied array or hash [perl #36051].
3534
3535=item *
44691e6f 3536
e8e35311 3537When trying to report C<Use of uninitialized value $Foo::BAR>, crashes could
e262cb24
FC
3538occur if the glob holding the global variable in question had been detached
3539from its original stash by, for example, C<delete $::{'Foo::'}>. This has
3540been fixed by disabling the reporting of variable names in those
e8e35311 3541cases.
44691e6f
AB
3542
3543=item *
3544
e8e35311
FC
3545During the restoration of a localised typeglob on scope exit, any
3546destructors called as a result would be able to see the typeglob in an
3547inconsistent state, containing freed entries, which could result in a
3548crash. This would affect code like this:
3549
3550 local *@;
3551 eval { die bless [] }; # puts an object in $@
3552 sub DESTROY {
3553 local $@; # boom
3554 }
3555
3556Now the glob entries are cleared before any destructors are called. This
3557also means that destructors can vivify entries in the glob. So perl tries
3558again and, if the entries are re-created too many times, dies with a
3559'panic: gp_free...' error message.
3560
3561=back
3562
3563=head2 Unicode
3564
3565=over
44691e6f 3566