1PERL5100DELTA(1) Perl Programmers Reference Guide PERL5100DELTA(1)
2
6 perl5100delta - what is new for perl 5.10.0
7
9 This document describes the differences between the 5.8.8 release and
10 the 5.10.0 release.
11 Many of the bug fixes in 5.10.0 were already seen in the 5.8.X
13 maintenance releases; they are not duplicated here and are documented
14 in the set of man pages named perl58[1-8]?delta.
15
17 The "feature" pragma
18 The "feature" pragma is used to enable new syntax that would break
19 Perl's backwards-compatibility with older releases of the language.
20 It's a lexical pragma, like "strict" or "warnings".
21 Currently the following new features are available: "switch" (adds a
23 switch statement), "say" (adds a "say" built-in function), and "state"
24 (adds a "state" keyword for declaring "static" variables). Those
25 features are described in their own sections of this document.
26 The "feature" pragma is also implicitly loaded when you require a
28 minimal perl version (with the "use VERSION" construct) greater than,
29 or equal to, 5.9.5. See feature for details.
30 New -E command-line switch
32 -E is equivalent to -e, but it implicitly enables all optional features
33 (like "use feature ":5.10"").
34 Defined-or operator
36 A new operator "//" (defined-or) has been implemented. The following
37 expression:
38 $a // $b
40 is merely equivalent to
42 defined $a ? $a : $b
44 and the statement
46 $c //= $d;
48 can now be used instead of
50 $c = $d unless defined $c;
52 The "//" operator has the same precedence and associativity as "||".
54 Special care has been taken to ensure that this operator Do What You
55 Mean while not breaking old code, but some edge cases involving the
56 empty regular expression may now parse differently. See perlop for
57 details.
58 Switch and Smart Match operator
60 Perl 5 now has a switch statement. It's available when "use feature
61 'switch'" is in effect. This feature introduces three new keywords,
62 "given", "when", and "default":
63 given ($foo) {
65 when (/^abc/) { $abc = 1; }
66 when (/^def/) { $def = 1; }
67 when (/^xyz/) { $xyz = 1; }
68 default { $nothing = 1; }
69 }
70 A more complete description of how Perl matches the switch variable
72 against the "when" conditions is given in "Switch statements" in
73 perlsyn.
74 This kind of match is called smart match, and it's also possible to use
76 it outside of switch statements, via the new "~~" operator. See "Smart
77 matching in detail" in perlsyn.
78 This feature was contributed by Robin Houston.
80 Regular expressions
82 Recursive Patterns
83 It is now possible to write recursive patterns without using the
84 "(??{})" construct. This new way is more efficient, and in many
85 cases easier to read.
86 Each capturing parenthesis can now be treated as an independent
88 pattern that can be entered by using the "(?PARNO)" syntax ("PARNO"
89 standing for "parenthesis number"). For example, the following
90 pattern will match nested balanced angle brackets:
91 /
93 ^ # start of line
94 ( # start capture buffer 1
95 < # match an opening angle bracket
96 (?: # match one of:
97 (?> # don't backtrack over the inside of this group
98 [^<>]+ # one or more non angle brackets
99 ) # end non backtracking group
100 | # ... or ...
101 (?1) # recurse to bracket 1 and try it again
102 )* # 0 or more times.
103 > # match a closing angle bracket
104 ) # end capture buffer one
105 $ # end of line
106 /x
107 PCRE users should note that Perl's recursive regex feature allows
109 backtracking into a recursed pattern, whereas in PCRE the recursion
110 is atomic or "possessive" in nature. As in the example above, you
111 can add (?>) to control this selectively. (Yves Orton)
112 Named Capture Buffers
114 It is now possible to name capturing parenthesis in a pattern and
115 refer to the captured contents by name. The naming syntax is
116 "(?<NAME>....)". It's possible to backreference to a named buffer
117 with the "\k<NAME>" syntax. In code, the new magical hashes "%+"
118 and "%-" can be used to access the contents of the capture buffers.
119 Thus, to replace all doubled chars with a single copy, one could
121 write
122 s/(?<letter>.)\k<letter>/$+{letter}/g
124 Only buffers with defined contents will be "visible" in the "%+"
126 hash, so it's possible to do something like
127 foreach my $name (keys %+) {
129 print "content of buffer '$name' is $+{$name}\n";
130 }
131 The "%-" hash is a bit more complete, since it will contain array
133 refs holding values from all capture buffers similarly named, if
134 there should be many of them.
135 "%+" and "%-" are implemented as tied hashes through the new module
137 "Tie::Hash::NamedCapture".
138 Users exposed to the .NET regex engine will find that the perl
140 implementation differs in that the numerical ordering of the
141 buffers is sequential, and not "unnamed first, then named". Thus in
142 the pattern
143 /(A)(?<B>B)(C)(?<D>D)/
145 $1 will be 'A', $2 will be 'B', $3 will be 'C' and $4 will be 'D'
147 and not $1 is 'A', $2 is 'C' and $3 is 'B' and $4 is 'D' that a
148 .NET programmer would expect. This is considered a feature. :-)
149 (Yves Orton)
150 Possessive Quantifiers
152 Perl now supports the "possessive quantifier" syntax of the "atomic
153 match" pattern. Basically a possessive quantifier matches as much
154 as it can and never gives any back. Thus it can be used to control
155 backtracking. The syntax is similar to non-greedy matching, except
156 instead of using a '?' as the modifier the '+' is used. Thus "?+",
157 "*+", "++", "{min,max}+" are now legal quantifiers. (Yves Orton)
158 Backtracking control verbs
160 The regex engine now supports a number of special-purpose backtrack
161 control verbs: (*THEN), (*PRUNE), (*MARK), (*SKIP), (*COMMIT),
162 (*FAIL) and (*ACCEPT). See perlre for their descriptions. (Yves
163 Orton)
164 Relative backreferences
166 A new syntax "\g{N}" or "\gN" where "N" is a decimal integer allows
167 a safer form of back-reference notation as well as allowing
168 relative backreferences. This should make it easier to generate and
169 embed patterns that contain backreferences. See "Capture buffers"
170 in perlre. (Yves Orton)
171 "\K" escape
173 The functionality of Jeff Pinyan's module Regexp::Keep has been
174 added to the core. In regular expressions you can now use the
175 special escape "\K" as a way to do something like floating length
176 positive lookbehind. It is also useful in substitutions like:
177 s/(foo)bar/$1/g
179 that can now be converted to
181 s/foo\Kbar//g
183 which is much more efficient. (Yves Orton)
185 Vertical and horizontal whitespace, and linebreak
187 Regular expressions now recognize the "\v" and "\h" escapes that
188 match vertical and horizontal whitespace, respectively. "\V" and
189 "\H" logically match their complements.
190 "\R" matches a generic linebreak, that is, vertical whitespace,
192 plus the multi-character sequence "\x0D\x0A".
193 "say()"
195 say() is a new built-in, only available when "use feature 'say'" is in
196 effect, that is similar to print(), but that implicitly appends a
197 newline to the printed string. See "say" in perlfunc. (Robin Houston)
198 Lexical $_
200 The default variable $_ can now be lexicalized, by declaring it like
201 any other lexical variable, with a simple
202 my $_;
204 The operations that default on $_ will use the lexically-scoped version
206 of $_ when it exists, instead of the global $_.
207 In a "map" or a "grep" block, if $_ was previously my'ed, then the $_
209 inside the block is lexical as well (and scoped to the block).
210 In a scope where $_ has been lexicalized, you can still have access to
212 the global version of $_ by using $::_, or, more simply, by overriding
213 the lexical declaration with "our $_". (Rafael Garcia-Suarez)
214 The "_" prototype
216 A new prototype character has been added. "_" is equivalent to "$" but
217 defaults to $_ if the corresponding argument isn't supplied (both "$"
218 and "_" denote a scalar). Due to the optional nature of the argument,
219 you can only use it at the end of a prototype, or before a semicolon.
220 This has a small incompatible consequence: the prototype() function has
222 been adjusted to return "_" for some built-ins in appropriate cases
223 (for example, "prototype('CORE::rmdir')"). (Rafael Garcia-Suarez)
224 UNITCHECK blocks
226 "UNITCHECK", a new special code block has been introduced, in addition
227 to "BEGIN", "CHECK", "INIT" and "END".
228 "CHECK" and "INIT" blocks, while useful for some specialized purposes,
230 are always executed at the transition between the compilation and the
231 execution of the main program, and thus are useless whenever code is
232 loaded at runtime. On the other hand, "UNITCHECK" blocks are executed
233 just after the unit which defined them has been compiled. See perlmod
234 for more information. (Alex Gough)
235 New Pragma, "mro"
237 A new pragma, "mro" (for Method Resolution Order) has been added. It
238 permits to switch, on a per-class basis, the algorithm that perl uses
239 to find inherited methods in case of a multiple inheritance hierarchy.
240 The default MRO hasn't changed (DFS, for Depth First Search). Another
241 MRO is available: the C3 algorithm. See mro for more information.
242 (Brandon Black)
243 Note that, due to changes in the implementation of class hierarchy
245 search, code that used to undef the *ISA glob will most probably break.
246 Anyway, undef'ing *ISA had the side-effect of removing the magic on the
247 @ISA array and should not have been done in the first place. Also, the
248 cache *::ISA::CACHE:: no longer exists; to force reset the @ISA cache,
249 you now need to use the "mro" API, or more simply to assign to @ISA
250 (e.g. with "@ISA = @ISA").
251 readdir() may return a "short filename" on Windows
253 The readdir() function may return a "short filename" when the long
254 filename contains characters outside the ANSI codepage. Similarly
255 Cwd::cwd() may return a short directory name, and glob() may return
256 short names as well. On the NTFS file system these short names can
257 always be represented in the ANSI codepage. This will not be true for
258 all other file system drivers; e.g. the FAT filesystem stores short
259 filenames in the OEM codepage, so some files on FAT volumes remain
260 unaccessible through the ANSI APIs.
261 Similarly, $^X, @INC, and $ENV{PATH} are preprocessed at startup to
263 make sure all paths are valid in the ANSI codepage (if possible).
264 The Win32::GetLongPathName() function now returns the UTF-8 encoded
266 correct long file name instead of using replacement characters to force
267 the name into the ANSI codepage. The new Win32::GetANSIPathName()
268 function can be used to turn a long pathname into a short one only if
269 the long one cannot be represented in the ANSI codepage.
270 Many other functions in the "Win32" module have been improved to accept
272 UTF-8 encoded arguments. Please see Win32 for details.
273 readpipe() is now overridable
275 The built-in function readpipe() is now overridable. Overriding it
276 permits also to override its operator counterpart, "qx//" (a.k.a.
277 "``"). Moreover, it now defaults to $_ if no argument is provided.
278 (Rafael Garcia-Suarez)
279 Default argument for readline()
281 readline() now defaults to *ARGV if no argument is provided. (Rafael
282 Garcia-Suarez)
283 state() variables
285 A new class of variables has been introduced. State variables are
286 similar to "my" variables, but are declared with the "state" keyword in
287 place of "my". They're visible only in their lexical scope, but their
288 value is persistent: unlike "my" variables, they're not undefined at
289 scope entry, but retain their previous value. (Rafael Garcia-Suarez,
290 Nicholas Clark)
291 To use state variables, one needs to enable them by using
293 use feature 'state';
295 or by using the "-E" command-line switch in one-liners. See
297 "Persistent Private Variables" in perlsub.
298 Stacked filetest operators
300 As a new form of syntactic sugar, it's now possible to stack up
301 filetest operators. You can now write "-f -w -x $file" in a row to mean
302 "-x $file && -w _ && -f _". See "-X" in perlfunc.
303 UNIVERSAL::DOES()
305 The "UNIVERSAL" class has a new method, "DOES()". It has been added to
306 solve semantic problems with the "isa()" method. "isa()" checks for
307 inheritance, while "DOES()" has been designed to be overridden when
308 module authors use other types of relations between classes (in
309 addition to inheritance). (chromatic)
310 See "$obj->DOES( ROLE )" in UNIVERSAL.
312 Formats
314 Formats were improved in several ways. A new field, "^*", can be used
315 for variable-width, one-line-at-a-time text. Null characters are now
316 handled correctly in picture lines. Using "@#" and "~~" together will
317 now produce a compile-time error, as those format fields are
318 incompatible. perlform has been improved, and miscellaneous bugs
319 fixed.
320 Byte-order modifiers for pack() and unpack()
322 There are two new byte-order modifiers, ">" (big-endian) and "<"
323 (little-endian), that can be appended to most pack() and unpack()
324 template characters and groups to force a certain byte-order for that
325 type or group. See "pack" in perlfunc and perlpacktut for details.
326 "no VERSION"
328 You can now use "no" followed by a version number to specify that you
329 want to use a version of perl older than the specified one.
330 "chdir", "chmod" and "chown" on filehandles
332 "chdir", "chmod" and "chown" can now work on filehandles as well as
333 filenames, if the system supports respectively "fchdir", "fchmod" and
334 "fchown", thanks to a patch provided by Gisle Aas.
335 OS groups
337 $( and $) now return groups in the order where the OS returns them,
338 thanks to Gisle Aas. This wasn't previously the case.
339 Recursive sort subs
341 You can now use recursive subroutines with sort(), thanks to Robin
342 Houston.
343 Exceptions in constant folding
345 The constant folding routine is now wrapped in an exception handler,
346 and if folding throws an exception (such as attempting to evaluate
347 0/0), perl now retains the current optree, rather than aborting the
348 whole program. Without this change, programs would not compile if they
349 had expressions that happened to generate exceptions, even though those
350 expressions were in code that could never be reached at runtime.
351 (Nicholas Clark, Dave Mitchell)
352 Source filters in @INC
354 It's possible to enhance the mechanism of subroutine hooks in @INC by
355 adding a source filter on top of the filehandle opened and returned by
356 the hook. This feature was planned a long time ago, but wasn't quite
357 working until now. See "require" in perlfunc for details. (Nicholas
358 Clark)
359 New internal variables
361 "${^RE_DEBUG_FLAGS}"
362 This variable controls what debug flags are in effect for the
363 regular expression engine when running under "use re "debug"". See
364 re for details.
365 "${^CHILD_ERROR_NATIVE}"
367 This variable gives the native status returned by the last pipe
368 close, backtick command, successful call to wait() or waitpid(), or
369 from the system() operator. See perlvar for details. (Contributed
370 by Gisle Aas.)
371 "${^RE_TRIE_MAXBUF}"
373 See "Trie optimisation of literal string alternations".
374 "${^WIN32_SLOPPY_STAT}"
376 See "Sloppy stat on Windows".
377 Miscellaneous
379 "unpack()" now defaults to unpacking the $_ variable.
380 "mkdir()" without arguments now defaults to $_.
382 The internal dump output has been improved, so that non-printable
384 characters such as newline and backspace are output in "\x" notation,
385 rather than octal.
386 The -C option can no longer be used on the "#!" line. It wasn't working
388 there anyway, since the standard streams are already set up at this
389 point in the execution of the perl interpreter. You can use binmode()
390 instead to get the desired behaviour.
391 UCD 5.0.0
393 The copy of the Unicode Character Database included in Perl 5 has been
394 updated to version 5.0.0.
395 MAD
397 MAD, which stands for Miscellaneous Attribute Decoration, is a still-
398 in-development work leading to a Perl 5 to Perl 6 converter. To enable
399 it, it's necessary to pass the argument "-Dmad" to Configure. The
400 obtained perl isn't binary compatible with a regular perl 5.10, and has
401 space and speed penalties; moreover not all regression tests still pass
402 with it. (Larry Wall, Nicholas Clark)
403 kill() on Windows
405 On Windows platforms, "kill(-9, $pid)" now kills a process tree. (On
406 UNIX, this delivers the signal to all processes in the same process
407 group.)
408
410 Packing and UTF-8 strings
411 The semantics of pack() and unpack() regarding UTF-8-encoded data has
412 been changed. Processing is now by default character per character
413 instead of byte per byte on the underlying encoding. Notably, code that
414 used things like "pack("a*", $string)" to see through the encoding of
415 string will now simply get back the original $string. Packed strings
416 can also get upgraded during processing when you store upgraded
417 characters. You can get the old behaviour by using "use bytes".
418 To be consistent with pack(), the "C0" in unpack() templates indicates
420 that the data is to be processed in character mode, i.e. character by
421 character; on the contrary, "U0" in unpack() indicates UTF-8 mode,
422 where the packed string is processed in its UTF-8-encoded Unicode form
423 on a byte by byte basis. This is reversed with regard to perl 5.8.X,
424 but now consistent between pack() and unpack().
425 Moreover, "C0" and "U0" can also be used in pack() templates to specify
427 respectively character and byte modes.
428 "C0" and "U0" in the middle of a pack or unpack format now switch to
430 the specified encoding mode, honoring parens grouping. Previously,
431 parens were ignored.
432 Also, there is a new pack() character format, "W", which is intended to
434 replace the old "C". "C" is kept for unsigned chars coded as bytes in
435 the strings internal representation. "W" represents unsigned (logical)
436 character values, which can be greater than 255. It is therefore more
437 robust when dealing with potentially UTF-8-encoded data (as "C" will
438 wrap values outside the range 0..255, and not respect the string
439 encoding).
440 In practice, that means that pack formats are now encoding-neutral,
442 except "C".
443 For consistency, "A" in unpack() format now trims all Unicode
445 whitespace from the end of the string. Before perl 5.9.2, it used to
446 strip only the classical ASCII space characters.
447 Byte/character count feature in unpack()
449 A new unpack() template character, ".", returns the number of bytes or
450 characters (depending on the selected encoding mode, see above) read so
451 far.
452 The $* and $# variables have been removed
454 $*, which was deprecated in favor of the "/s" and "/m" regexp
455 modifiers, has been removed.
456 The deprecated $# variable (output format for numbers) has been
458 removed.
459 Two new severe warnings, "$#/$* is no longer supported", have been
461 added.
462 substr() lvalues are no longer fixed-length
464 The lvalues returned by the three argument form of substr() used to be
465 a "fixed length window" on the original string. In some cases this
466 could cause surprising action at distance or other undefined behaviour.
467 Now the length of the window adjusts itself to the length of the string
468 assigned to it.
469 Parsing of "-f _"
471 The identifier "_" is now forced to be a bareword after a filetest
472 operator. This solves a number of misparsing issues when a global "_"
473 subroutine is defined.
474 ":unique"
476 The ":unique" attribute has been made a no-op, since its current
477 implementation was fundamentally flawed and not threadsafe.
478 Effect of pragmas in eval
480 The compile-time value of the "%^H" hint variable can now propagate
481 into eval("")uated code. This makes it more useful to implement lexical
482 pragmas.
483 As a side-effect of this, the overloaded-ness of constants now
485 propagates into eval("").
486 chdir FOO
488 A bareword argument to chdir() is now recognized as a file handle.
489 Earlier releases interpreted the bareword as a directory name. (Gisle
490 Aas)
491 Handling of .pmc files
493 An old feature of perl was that before "require" or "use" look for a
494 file with a .pm extension, they will first look for a similar filename
495 with a .pmc extension. If this file is found, it will be loaded in
496 place of any potentially existing file ending in a .pm extension.
497 Previously, .pmc files were loaded only if more recent than the
499 matching .pm file. Starting with 5.9.4, they'll be always loaded if
500 they exist.
501 $^V is now a "version" object instead of a v-string
503 $^V can still be used with the %vd format in printf, but any character-
504 level operations will now access the string representation of the
505 "version" object and not the ordinals of a v-string. Expressions like
506 "substr($^V, 0, 2)" or "split //, $^V" no longer work and must be
507 rewritten.
508 @- and @+ in patterns
510 The special arrays "@-" and "@+" are no longer interpolated in regular
511 expressions. (Sadahiro Tomoyuki)
512 $AUTOLOAD can now be tainted
514 If you call a subroutine by a tainted name, and if it defers to an
515 AUTOLOAD function, then $AUTOLOAD will be (correctly) tainted. (Rick
516 Delaney)
517 Tainting and printf
519 When perl is run under taint mode, "printf()" and "sprintf()" will now
520 reject any tainted format argument. (Rafael Garcia-Suarez)
521 undef and signal handlers
523 Undefining or deleting a signal handler via "undef $SIG{FOO}" is now
524 equivalent to setting it to 'DEFAULT'. (Rafael Garcia-Suarez)
525 strictures and dereferencing in defined()
527 "use strict 'refs'" was ignoring taking a hard reference in an argument
528 to defined(), as in :
529 use strict 'refs';
531 my $x = 'foo';
532 if (defined $$x) {...}
533 This now correctly produces the run-time error "Can't use string as a
535 SCALAR ref while "strict refs" in use".
536 "defined @$foo" and "defined %$bar" are now also subject to "strict
538 'refs'" (that is, $foo and $bar shall be proper references there.)
539 ("defined(@foo)" and "defined(%bar)" are discouraged constructs
540 anyway.) (Nicholas Clark)
541 "(?p{})" has been removed
543 The regular expression construct "(?p{})", which was deprecated in perl
544 5.8, has been removed. Use "(??{})" instead. (Rafael Garcia-Suarez)
545 Pseudo-hashes have been removed
547 Support for pseudo-hashes has been removed from Perl 5.9. (The "fields"
548 pragma remains here, but uses an alternate implementation.)
549 Removal of the bytecode compiler and of perlcc
551 "perlcc", the byteloader and the supporting modules (B::C, B::CC,
552 B::Bytecode, etc.) are no longer distributed with the perl sources.
553 Those experimental tools have never worked reliably, and, due to the
554 lack of volunteers to keep them in line with the perl interpreter
555 developments, it was decided to remove them instead of shipping a
556 broken version of those. The last version of those modules can be
557 found with perl 5.9.4.
558 However the B compiler framework stays supported in the perl core, as
560 with the more useful modules it has permitted (among others, B::Deparse
561 and B::Concise).
562 Removal of the JPL
564 The JPL (Java-Perl Lingo) has been removed from the perl sources
565 tarball.
566 Recursive inheritance detected earlier
568 Perl will now immediately throw an exception if you modify any
569 package's @ISA in such a way that it would cause recursive inheritance.
570 Previously, the exception would not occur until Perl attempted to make
572 use of the recursive inheritance while resolving a method or doing a
573 "$foo->isa($bar)" lookup.
574
576 Upgrading individual core modules
577 Even more core modules are now also available separately through the
578 CPAN. If you wish to update one of these modules, you don't need to
579 wait for a new perl release. From within the cpan shell, running the
580 'r' command will report on modules with upgrades available. See
581 "perldoc CPAN" for more information.
582 Pragmata Changes
584 "feature"
585 The new pragma "feature" is used to enable new features that might
586 break old code. See "The "feature" pragma" above.
587 "mro"
589 This new pragma enables to change the algorithm used to resolve
590 inherited methods. See "New Pragma, "mro"" above.
591 Scoping of the "sort" pragma
593 The "sort" pragma is now lexically scoped. Its effect used to be
594 global.
595 Scoping of "bignum", "bigint", "bigrat"
597 The three numeric pragmas "bignum", "bigint" and "bigrat" are now
598 lexically scoped. (Tels)
599 "base"
601 The "base" pragma now warns if a class tries to inherit from
602 itself. (Curtis "Ovid" Poe)
603 "strict" and "warnings"
605 "strict" and "warnings" will now complain loudly if they are loaded
606 via incorrect casing (as in "use Strict;"). (Johan Vromans)
607 "version"
609 The "version" module provides support for version objects.
610 "warnings"
612 The "warnings" pragma doesn't load "Carp" anymore. That means that
613 code that used "Carp" routines without having loaded it at compile
614 time might need to be adjusted; typically, the following (faulty)
615 code won't work anymore, and will require parentheses to be added
616 after the function name:
617 use warnings;
619 require Carp;
620 Carp::confess 'argh';
621 "less"
623 "less" now does something useful (or at least it tries to). In
624 fact, it has been turned into a lexical pragma. So, in your
625 modules, you can now test whether your users have requested to use
626 less CPU, or less memory, less magic, or maybe even less fat. See
627 less for more. (Joshua ben Jore)
628 New modules
630 · "encoding::warnings", by Audrey Tang, is a module to emit warnings
631 whenever an ASCII character string containing high-bit bytes is
632 implicitly converted into UTF-8. It's a lexical pragma since Perl
633 5.9.4; on older perls, its effect is global.
634 · "Module::CoreList", by Richard Clamp, is a small handy module that
636 tells you what versions of core modules ship with any versions of
637 Perl 5. It comes with a command-line frontend, "corelist".
638 · "Math::BigInt::FastCalc" is an XS-enabled, and thus faster, version
640 of "Math::BigInt::Calc".
641 · "Compress::Zlib" is an interface to the zlib compression library.
643 It comes with a bundled version of zlib, so having a working zlib
644 is not a prerequisite to install it. It's used by "Archive::Tar"
645 (see below).
646 · "IO::Zlib" is an "IO::"-style interface to "Compress::Zlib".
648 · "Archive::Tar" is a module to manipulate "tar" archives.
650 · "Digest::SHA" is a module used to calculate many types of SHA
652 digests, has been included for SHA support in the CPAN module.
653 · "ExtUtils::CBuilder" and "ExtUtils::ParseXS" have been added.
655 · "Hash::Util::FieldHash", by Anno Siegel, has been added. This
657 module provides support for field hashes: hashes that maintain an
658 association of a reference with a value, in a thread-safe garbage-
659 collected way. Such hashes are useful to implement inside-out
660 objects.
661 · "Module::Build", by Ken Williams, has been added. It's an
663 alternative to "ExtUtils::MakeMaker" to build and install perl
664 modules.
665 · "Module::Load", by Jos Boumans, has been added. It provides a
667 single interface to load Perl modules and .pl files.
668 · "Module::Loaded", by Jos Boumans, has been added. It's used to mark
670 modules as loaded or unloaded.
671 · "Package::Constants", by Jos Boumans, has been added. It's a simple
673 helper to list all constants declared in a given package.
674 · "Win32API::File", by Tye McQueen, has been added (for Windows
676 builds). This module provides low-level access to Win32 system API
677 calls for files/dirs.
678 · "Locale::Maketext::Simple", needed by CPANPLUS, is a simple wrapper
680 around "Locale::Maketext::Lexicon". Note that
681 "Locale::Maketext::Lexicon" isn't included in the perl core; the
682 behaviour of "Locale::Maketext::Simple" gracefully degrades when
683 the later isn't present.
684 · "Params::Check" implements a generic input parsing/checking
686 mechanism. It is used by CPANPLUS.
687 · "Term::UI" simplifies the task to ask questions at a terminal
689 prompt.
690 · "Object::Accessor" provides an interface to create per-object
692 accessors.
693 · "Module::Pluggable" is a simple framework to create modules that
695 accept pluggable sub-modules.
696 · "Module::Load::Conditional" provides simple ways to query and
698 possibly load installed modules.
699 · "Time::Piece" provides an object oriented interface to time
701 functions, overriding the built-ins localtime() and gmtime().
702 · "IPC::Cmd" helps to find and run external commands, possibly
704 interactively.
705 · "File::Fetch" provide a simple generic file fetching mechanism.
707 · "Log::Message" and "Log::Message::Simple" are used by the log
709 facility of "CPANPLUS".
710 · "Archive::Extract" is a generic archive extraction mechanism for
712 .tar (plain, gziped or bzipped) or .zip files.
713 · "CPANPLUS" provides an API and a command-line tool to access the
715 CPAN mirrors.
716 · "Pod::Escapes" provides utilities that are useful in decoding Pod
718 E<...> sequences.
719 · "Pod::Simple" is now the backend for several of the Pod-related
721 modules included with Perl.
722 Selected Changes to Core Modules
724 "Attribute::Handlers"
725 "Attribute::Handlers" can now report the caller's file and line
726 number. (David Feldman)
727 All interpreted attributes are now passed as array references.
729 (Damian Conway)
730 "B::Lint"
732 "B::Lint" is now based on "Module::Pluggable", and so can be
733 extended with plugins. (Joshua ben Jore)
734 "B" It's now possible to access the lexical pragma hints ("%^H") by
736 using the method B::COP::hints_hash(). It returns a "B::RHE"
737 object, which in turn can be used to get a hash reference via the
738 method B::RHE::HASH(). (Joshua ben Jore)
739 "Thread"
741 As the old 5005thread threading model has been removed, in favor of
742 the ithreads scheme, the "Thread" module is now a compatibility
743 wrapper, to be used in old code only. It has been removed from the
744 default list of dynamic extensions.
745
747 perl -d
748 The Perl debugger can now save all debugger commands for sourcing
749 later; notably, it can now emulate stepping backwards, by
750 restarting and rerunning all bar the last command from a saved
751 command history.
752 It can also display the parent inheritance tree of a given class,
754 with the "i" command.
755 ptar
757 "ptar" is a pure perl implementation of "tar" that comes with
758 "Archive::Tar".
759 ptardiff
761 "ptardiff" is a small utility used to generate a diff between the
762 contents of a tar archive and a directory tree. Like "ptar", it
763 comes with "Archive::Tar".
764 shasum
766 "shasum" is a command-line utility, used to print or to check SHA
767 digests. It comes with the new "Digest::SHA" module.
768 corelist
770 The "corelist" utility is now installed with perl (see "New
771 modules" above).
772 h2ph and h2xs
774 "h2ph" and "h2xs" have been made more robust with regard to
775 "modern" C code.
776 "h2xs" implements a new option "--use-xsloader" to force use of
778 "XSLoader" even in backwards compatible modules.
779 The handling of authors' names that had apostrophes has been fixed.
781 Any enums with negative values are now skipped.
783 perlivp
785 "perlivp" no longer checks for *.ph files by default. Use the new
786 "-a" option to run all tests.
787 find2perl
789 "find2perl" now assumes "-print" as a default action. Previously,
790 it needed to be specified explicitly.
791 Several bugs have been fixed in "find2perl", regarding "-exec" and
793 "-eval". Also the options "-path", "-ipath" and "-iname" have been
794 added.
795 config_data
797 "config_data" is a new utility that comes with "Module::Build". It
798 provides a command-line interface to the configuration of Perl
799 modules that use Module::Build's framework of configurability (that
800 is, *::ConfigData modules that contain local configuration
801 information for their parent modules.)
802 cpanp
804 "cpanp", the CPANPLUS shell, has been added. ("cpanp-run-perl", a
805 helper for CPANPLUS operation, has been added too, but isn't
806 intended for direct use).
807 cpan2dist
809 "cpan2dist" is a new utility that comes with CPANPLUS. It's a tool
810 to create distributions (or packages) from CPAN modules.
811 pod2html
813 The output of "pod2html" has been enhanced to be more customizable
814 via CSS. Some formatting problems were also corrected. (Jari Aalto)
815
817 The perlpragma manpage documents how to write one's own lexical pragmas
818 in pure Perl (something that is possible starting with 5.9.4).
819 The new perlglossary manpage is a glossary of terms used in the Perl
821 documentation, technical and otherwise, kindly provided by O'Reilly
822 Media, Inc.
823 The perlreguts manpage, courtesy of Yves Orton, describes internals of
825 the Perl regular expression engine.
826 The perlreapi manpage describes the interface to the perl interpreter
828 used to write pluggable regular expression engines (by var Arnfjoerd`
829 Bjarmason).
830 The perlunitut manpage is an tutorial for programming with Unicode and
832 string encodings in Perl, courtesy of Juerd Waalboer.
833 A new manual page, perlunifaq (the Perl Unicode FAQ), has been added
835 (Juerd Waalboer).
836 The perlcommunity manpage gives a description of the Perl community on
838 the Internet and in real life. (Edgar "Trizor" Bering)
839 The CORE manual page documents the "CORE::" namespace. (Tels)
841 The long-existing feature of "/(?{...})/" regexps setting $_ and pos()
843 is now documented.
844
846 In-place sorting
847 Sorting arrays in place ("@a = sort @a") is now optimized to avoid
848 making a temporary copy of the array.
849 Likewise, "reverse sort ..." is now optimized to sort in reverse,
851 avoiding the generation of a temporary intermediate list.
852 Lexical array access
854 Access to elements of lexical arrays via a numeric constant between 0
855 and 255 is now faster. (This used to be only the case for global
856 arrays.)
857 XS-assisted SWASHGET
859 Some pure-perl code that perl was using to retrieve Unicode properties
860 and transliteration mappings has been reimplemented in XS.
861 Constant subroutines
863 The interpreter internals now support a far more memory efficient form
864 of inlineable constants. Storing a reference to a constant value in a
865 symbol table is equivalent to a full typeglob referencing a constant
866 subroutine, but using about 400 bytes less memory. This proxy constant
867 subroutine is automatically upgraded to a real typeglob with subroutine
868 if necessary. The approach taken is analogous to the existing space
869 optimisation for subroutine stub declarations, which are stored as
870 plain scalars in place of the full typeglob.
871 Several of the core modules have been converted to use this feature for
873 their system dependent constants - as a result "use POSIX;" now takes
874 about 200K less memory.
875 "PERL_DONT_CREATE_GVSV"
877 The new compilation flag "PERL_DONT_CREATE_GVSV", introduced as an
878 option in perl 5.8.8, is turned on by default in perl 5.9.3. It
879 prevents perl from creating an empty scalar with every new typeglob.
880 See perl589delta for details.
881 Weak references are cheaper
883 Weak reference creation is now O(1) rather than O(n), courtesy of
884 Nicholas Clark. Weak reference deletion remains O(n), but if deletion
885 only happens at program exit, it may be skipped completely.
886 sort() enhancements
888 Salvador Fandin~o provided improvements to reduce the memory usage of
889 "sort" and to speed up some cases.
890 Memory optimisations
892 Several internal data structures (typeglobs, GVs, CVs, formats) have
893 been restructured to use less memory. (Nicholas Clark)
894 UTF-8 cache optimisation
896 The UTF-8 caching code is now more efficient, and used more often.
897 (Nicholas Clark)
898 Sloppy stat on Windows
900 On Windows, perl's stat() function normally opens the file to determine
901 the link count and update attributes that may have been changed through
902 hard links. Setting ${^WIN32_SLOPPY_STAT} to a true value speeds up
903 stat() by not performing this operation. (Jan Dubois)
904 Regular expressions optimisations
906 Engine de-recursivised
907 The regular expression engine is no longer recursive, meaning that
908 patterns that used to overflow the stack will either die with
909 useful explanations, or run to completion, which, since they were
910 able to blow the stack before, will likely take a very long time to
911 happen. If you were experiencing the occasional stack overflow (or
912 segfault) and upgrade to discover that now perl apparently hangs
913 instead, look for a degenerate regex. (Dave Mitchell)
914 Single char char-classes treated as literals
916 Classes of a single character are now treated the same as if the
917 character had been used as a literal, meaning that code that uses
918 char-classes as an escaping mechanism will see a speedup. (Yves
919 Orton)
920 Trie optimisation of literal string alternations
922 Alternations, where possible, are optimised into more efficient
923 matching structures. String literal alternations are merged into a
924 trie and are matched simultaneously. This means that instead of
925 O(N) time for matching N alternations at a given point, the new
926 code performs in O(1) time. A new special variable,
927 ${^RE_TRIE_MAXBUF}, has been added to fine-tune this optimization.
928 (Yves Orton)
929 Note: Much code exists that works around perl's historic poor
931 performance on alternations. Often the tricks used to do so will
932 disable the new optimisations. Hopefully the utility modules used
933 for this purpose will be educated about these new optimisations.
934 Aho-Corasick start-point optimisation
936 When a pattern starts with a trie-able alternation and there aren't
937 better optimisations available, the regex engine will use Aho-
938 Corasick matching to find the start point. (Yves Orton)
939
941 Configuration improvements
942 "-Dusesitecustomize"
943 Run-time customization of @INC can be enabled by passing the
944 "-Dusesitecustomize" flag to Configure. When enabled, this will
945 make perl run $sitelibexp/sitecustomize.pl before anything else.
946 This script can then be set up to add additional entries to @INC.
947 Relocatable installations
949 There is now Configure support for creating a relocatable perl
950 tree. If you Configure with "-Duserelocatableinc", then the paths
951 in @INC (and everything else in %Config) can be optionally located
952 via the path of the perl executable.
953 That means that, if the string ".../" is found at the start of any
955 path, it's substituted with the directory of $^X. So, the
956 relocation can be configured on a per-directory basis, although the
957 default with "-Duserelocatableinc" is that everything is relocated.
958 The initial install is done to the original configured prefix.
959 strlcat() and strlcpy()
961 The configuration process now detects whether strlcat() and
962 strlcpy() are available. When they are not available, perl's own
963 version is used (from Russ Allbery's public domain implementation).
964 Various places in the perl interpreter now use them. (Steve Peters)
965 "d_pseudofork" and "d_printf_format_null"
967 A new configuration variable, available as $Config{d_pseudofork} in
968 the Config module, has been added, to distinguish real fork()
969 support from fake pseudofork used on Windows platforms.
970 A new configuration variable, "d_printf_format_null", has been
972 added, to see if printf-like formats are allowed to be NULL.
973 Configure help
975 "Configure -h" has been extended with the most commonly used
976 options.
977 Compilation improvements
979 Parallel build
980 Parallel makes should work properly now, although there may still
981 be problems if "make test" is instructed to run in parallel.
982 Borland's compilers support
984 Building with Borland's compilers on Win32 should work more
985 smoothly. In particular Steve Hay has worked to side step many
986 warnings emitted by their compilers and at least one C compiler
987 internal error.
988 Static build on Windows
990 Perl extensions on Windows now can be statically built into the
991 Perl DLL.
992 Also, it's now possible to build a "perl-static.exe" that doesn't
994 depend on the Perl DLL on Win32. See the Win32 makefiles for
995 details. (Vadim Konovalov)
996 ppport.h files
998 All ppport.h files in the XS modules bundled with perl are now
999 autogenerated at build time. (Marcus Holland-Moritz)
1000 C++ compatibility
1002 Efforts have been made to make perl and the core XS modules
1003 compilable with various C++ compilers (although the situation is
1004 not perfect with some of the compilers on some of the platforms
1005 tested.)
1006 Support for Microsoft 64-bit compiler
1008 Support for building perl with Microsoft's 64-bit compiler has been
1009 improved. (ActiveState)
1010 Visual C++
1012 Perl can now be compiled with Microsoft Visual C++ 2005 (and 2008
1013 Beta 2).
1014 Win32 builds
1016 All win32 builds (MS-Win, WinCE) have been merged and cleaned up.
1017 Installation improvements
1019 Module auxiliary files
1020 README files and changelogs for CPAN modules bundled with perl are
1021 no longer installed.
1022 New Or Improved Platforms
1024 Perl has been reported to work on Symbian OS. See perlsymbian for more
1025 information.
1026 Many improvements have been made towards making Perl work correctly on
1028 z/OS.
1029 Perl has been reported to work on DragonFlyBSD and MidnightBSD.
1031 Perl has also been reported to work on NexentaOS (
1033 http://www.gnusolaris.org/ ).
1034 The VMS port has been improved. See perlvms.
1036 Support for Cray XT4 Catamount/Qk has been added. See
1038 hints/catamount.sh in the source code distribution for more
1039 information.
1040 Vendor patches have been merged for RedHat and Gentoo.
1042 DynaLoader::dl_unload_file() now works on Windows.
1044
1046 strictures in regexp-eval blocks
1047 "strict" wasn't in effect in regexp-eval blocks ("/(?{...})/").
1048 Calling CORE::require()
1050 CORE::require() and CORE::do() were always parsed as require() and
1051 do() when they were overridden. This is now fixed.
1052 Subscripts of slices
1054 You can now use a non-arrowed form for chained subscripts after a
1055 list slice, like in:
1056 ({foo => "bar"})[0]{foo}
1058 This used to be a syntax error; a "->" was required.
1060 "no warnings 'category'" works correctly with -w
1062 Previously when running with warnings enabled globally via "-w",
1063 selective disabling of specific warning categories would actually
1064 turn off all warnings. This is now fixed; now "no warnings 'io';"
1065 will only turn off warnings in the "io" class. Previously it would
1066 erroneously turn off all warnings.
1067 threads improvements
1069 Several memory leaks in ithreads were closed. Also, ithreads were
1070 made less memory-intensive.
1071 "threads" is now a dual-life module, also available on CPAN. It has
1073 been expanded in many ways. A kill() method is available for thread
1074 signalling. One can get thread status, or the list of running or
1075 joinable threads.
1076 A new "threads->exit()" method is used to exit from the application
1078 (this is the default for the main thread) or from the current
1079 thread only (this is the default for all other threads). On the
1080 other hand, the exit() built-in now always causes the whole
1081 application to terminate. (Jerry D. Hedden)
1082 chr() and negative values
1084 chr() on a negative value now gives "\x{FFFD}", the Unicode
1085 replacement character, unless when the "bytes" pragma is in effect,
1086 where the low eight bits of the value are used.
1087 PERL5SHELL and tainting
1089 On Windows, the PERL5SHELL environment variable is now checked for
1090 taintedness. (Rafael Garcia-Suarez)
1091 Using *FILE{IO}
1093 "stat()" and "-X" filetests now treat *FILE{IO} filehandles like
1094 *FILE filehandles. (Steve Peters)
1095 Overloading and reblessing
1097 Overloading now works when references are reblessed into another
1098 class. Internally, this has been implemented by moving the flag
1099 for "overloading" from the reference to the referent, which
1100 logically is where it should always have been. (Nicholas Clark)
1101 Overloading and UTF-8
1103 A few bugs related to UTF-8 handling with objects that have
1104 stringification overloaded have been fixed. (Nicholas Clark)
1105 eval memory leaks fixed
1107 Traditionally, "eval 'syntax error'" has leaked badly. Many (but
1108 not all) of these leaks have now been eliminated or reduced. (Dave
1109 Mitchell)
1110 Random device on Windows
1112 In previous versions, perl would read the file /dev/urandom if it
1113 existed when seeding its random number generator. That file is
1114 unlikely to exist on Windows, and if it did would probably not
1115 contain appropriate data, so perl no longer tries to read it on
1116 Windows. (Alex Davies)
1117 PERLIO_DEBUG
1119 The "PERLIO_DEBUG" environment variable no longer has any effect
1120 for setuid scripts and for scripts run with -T.
1121 Moreover, with a thread-enabled perl, using "PERLIO_DEBUG" could
1123 lead to an internal buffer overflow. This has been fixed.
1124 PerlIO::scalar and read-only scalars
1126 PerlIO::scalar will now prevent writing to read-only scalars.
1127 Moreover, seek() is now supported with PerlIO::scalar-based
1128 filehandles, the underlying string being zero-filled as needed.
1129 (Rafael, Jarkko Hietaniemi)
1130 study() and UTF-8
1132 study() never worked for UTF-8 strings, but could lead to false
1133 results. It's now a no-op on UTF-8 data. (Yves Orton)
1134 Critical signals
1136 The signals SIGILL, SIGBUS and SIGSEGV are now always delivered in
1137 an "unsafe" manner (contrary to other signals, that are deferred
1138 until the perl interpreter reaches a reasonably stable state; see
1139 "Deferred Signals (Safe Signals)" in perlipc). (Rafael)
1140 @INC-hook fix
1142 When a module or a file is loaded through an @INC-hook, and when
1143 this hook has set a filename entry in %INC, __FILE__ is now set for
1144 this module accordingly to the contents of that %INC entry.
1145 (Rafael)
1146 "-t" switch fix
1148 The "-w" and "-t" switches can now be used together without messing
1149 up which categories of warnings are activated. (Rafael)
1150 Duping UTF-8 filehandles
1152 Duping a filehandle which has the ":utf8" PerlIO layer set will now
1153 properly carry that layer on the duped filehandle. (Rafael)
1154 Localisation of hash elements
1156 Localizing a hash element whose key was given as a variable didn't
1157 work correctly if the variable was changed while the local() was in
1158 effect (as in "local $h{$x}; ++$x"). (Bo Lindbergh)
1159
1161 Use of uninitialized value
1162 Perl will now try to tell you the name of the variable (if any)
1163 that was undefined.
1164 Deprecated use of my() in false conditional
1166 A new deprecation warning, Deprecated use of my() in false
1167 conditional, has been added, to warn against the use of the dubious
1168 and deprecated construct
1169 my $x if 0;
1171 See perldiag. Use "state" variables instead.
1173 !=~ should be !~
1175 A new warning, "!=~ should be !~", is emitted to prevent this
1176 misspelling of the non-matching operator.
1177 Newline in left-justified string
1179 The warning Newline in left-justified string has been removed.
1180 Too late for "-T" option
1182 The error Too late for "-T" option has been reformulated to be more
1183 descriptive.
1184 "%s" variable %s masks earlier declaration
1186 This warning is now emitted in more consistent cases; in short,
1187 when one of the declarations involved is a "my" variable:
1188 my $x; my $x; # warns
1190 my $x; our $x; # warns
1191 our $x; my $x; # warns
1192 On the other hand, the following:
1194 our $x; our $x;
1196 now gives a ""our" variable %s redeclared" warning.
1198 readdir()/closedir()/etc. attempted on invalid dirhandle
1200 These new warnings are now emitted when a dirhandle is used but is
1201 either closed or not really a dirhandle.
1202 Opening dirhandle/filehandle %s also as a file/directory
1204 Two deprecation warnings have been added: (Rafael)
1205 Opening dirhandle %s also as a file
1207 Opening filehandle %s also as a directory
1208 Use of -P is deprecated
1210 Perl's command-line switch "-P" is now deprecated.
1211 v-string in use/require is non-portable
1213 Perl will warn you against potential backwards compatibility
1214 problems with the "use VERSION" syntax.
1215 perl -V
1217 "perl -V" has several improvements, making it more useable from
1218 shell scripts to get the value of configuration variables. See
1219 perlrun for details.
1220
1222 In general, the source code of perl has been refactored, tidied up, and
1223 optimized in many places. Also, memory management and allocation has
1224 been improved in several points.
1225 When compiling the perl core with gcc, as many gcc warning flags are
1227 turned on as is possible on the platform. (This quest for cleanliness
1228 doesn't extend to XS code because we cannot guarantee the tidiness of
1229 code we didn't write.) Similar strictness flags have been added or
1230 tightened for various other C compilers.
1231 Reordering of SVt_* constants
1233 The relative ordering of constants that define the various types of
1234 "SV" have changed; in particular, "SVt_PVGV" has been moved before
1235 "SVt_PVLV", "SVt_PVAV", "SVt_PVHV" and "SVt_PVCV". This is unlikely to
1236 make any difference unless you have code that explicitly makes
1237 assumptions about that ordering. (The inheritance hierarchy of "B::*"
1238 objects has been changed to reflect this.)
1239 Elimination of SVt_PVBM
1241 Related to this, the internal type "SVt_PVBM" has been been removed.
1242 This dedicated type of "SV" was used by the "index" operator and parts
1243 of the regexp engine to facilitate fast Boyer-Moore matches. Its use
1244 internally has been replaced by "SV"s of type "SVt_PVGV".
1245 New type SVt_BIND
1247 A new type "SVt_BIND" has been added, in readiness for the project to
1248 implement Perl 6 on 5. There deliberately is no implementation yet, and
1249 they cannot yet be created or destroyed.
1250 Removal of CPP symbols
1252 The C preprocessor symbols "PERL_PM_APIVERSION" and
1253 "PERL_XS_APIVERSION", which were supposed to give the version number of
1254 the oldest perl binary-compatible (resp. source-compatible) with the
1255 present one, were not used, and sometimes had misleading values. They
1256 have been removed.
1257 Less space is used by ops
1259 The "BASEOP" structure now uses less space. The "op_seq" field has been
1260 removed and replaced by a single bit bit-field "op_opt". "op_type" is
1261 now 9 bits long. (Consequently, the "B::OP" class doesn't provide an
1262 "seq" method anymore.)
1263 New parser
1265 perl's parser is now generated by bison (it used to be generated by
1266 byacc.) As a result, it seems to be a bit more robust.
1267 Also, Dave Mitchell improved the lexer debugging output under "-DT".
1269 Use of "const"
1271 Andy Lester supplied many improvements to determine which function
1272 parameters and local variables could actually be declared "const" to
1273 the C compiler. Steve Peters provided new *_set macros and reworked the
1274 core to use these rather than assigning to macros in LVALUE context.
1275 Mathoms
1277 A new file, mathoms.c, has been added. It contains functions that are
1278 no longer used in the perl core, but that remain available for binary
1279 or source compatibility reasons. However, those functions will not be
1280 compiled in if you add "-DNO_MATHOMS" in the compiler flags.
1281 "AvFLAGS" has been removed
1283 The "AvFLAGS" macro has been removed.
1284 "av_*" changes
1286 The "av_*()" functions, used to manipulate arrays, no longer accept
1287 null "AV*" parameters.
1288 $^H and %^H
1290 The implementation of the special variables $^H and %^H has changed, to
1291 allow implementing lexical pragmas in pure Perl.
1292 B:: modules inheritance changed
1294 The inheritance hierarchy of "B::" modules has changed; "B::NV" now
1295 inherits from "B::SV" (it used to inherit from "B::IV").
1296 Anonymous hash and array constructors
1298 The anonymous hash and array constructors now take 1 op in the optree
1299 instead of 3, now that pp_anonhash and pp_anonlist return a reference
1300 to an hash/array when the op is flagged with OPf_SPECIAL. (Nicholas
1301 Clark)
1302
1304 There's still a remaining problem in the implementation of the lexical
1305 $_: it doesn't work inside "/(?{...})/" blocks. (See the TODO test in
1306 t/op/mydef.t.)
1307 Stacked filetest operators won't work when the "filetest" pragma is in
1309 effect, because they rely on the stat() buffer "_" being populated, and
1310 filetest bypasses stat().
1311 UTF-8 problems
1313 The handling of Unicode still is unclean in several places, where it's
1314 dependent on whether a string is internally flagged as UTF-8. This will
1315 be made more consistent in perl 5.12, but that won't be possible
1316 without a certain amount of backwards incompatibility.
1317
1319 When compiled with g++ and thread support on Linux, it's reported that
1320 the $! stops working correctly. This is related to the fact that the
1321 glibc provides two strerror_r(3) implementation, and perl selects the
1322 wrong one.
1323
1325 If you find what you think is a bug, you might check the articles
1326 recently posted to the comp.lang.perl.misc newsgroup and the perl bug
1327 database at http://rt.perl.org/rt3/ . There may also be information at
1328 http://www.perl.org/ , the Perl Home Page.
1329 If you believe you have an unreported bug, please run the perlbug
1331 program included with your release. Be sure to trim your bug down to a
1332 tiny but sufficient test case. Your bug report, along with the output
1333 of "perl -V", will be sent off to perlbug@perl.org to be analysed by
1334 the Perl porting team.
1335
1337 The Changes file and the perl590delta to perl595delta man pages for
1338 exhaustive details on what changed.
1339 The INSTALL file for how to build Perl.
1341 The README file for general stuff.
1343 The Artistic and Copying files for copyright information.
1345perl v5.10.1 2009-08-11 PERL5100DELTA(1)