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ba370e9b 1=head1 NAME
cc0fca54 2
f39f21d8 3perldelta - what is new for perl v5.8.0
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4
5=head1 DESCRIPTION
6
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7This document describes differences between the 5.6.0 release
8and the 5.8.0 release.
f39f21d8 9
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10Many of the bug fixes in 5.8.0 were already seen in the 5.6.1
11maintenance release since the two releases were kept closely
12coordinated.
13
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14If you are upgrading from Perl 5.005_03, you might also want
15to read L<perl56delta>.
16
44da0e71 17=head1 Highlights In 5.8.0
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18
19=over 4
20
21=item *
22
23Better Unicode support
24
25=item *
26
27New Thread Implementation
28
29=item *
30
31Many New Modules
32
33=item *
34
35Better Numeric Accuracy
36
37=item *
38
39Safe Signals
40
41=item *
42
43More Extensive Regression Testing
44
45=back
46
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47=head1 Incompatible Changes
48
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49=head2 64-bit platforms and malloc
50
057b7f2b 51If your pointers are 64 bits wide, the Perl malloc is no longer being
c2e23569 52used because it does not work well with 8-byte pointers. Also,
61947107 53usually the system mallocs on such platforms are much better optimized
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54for such large memory models than the Perl malloc. Some memory-hungry
55Perl applications like the PDL don't work well with Perl's malloc.
56Finally, other applications than Perl (like modperl) tend to prefer
57the system malloc. Such platforms include Alpha and 64-bit HPPA,
58MIPS, PPC, and Sparc.
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59
60=head2 AIX Dynaloading
61
62The AIX dynaloading now uses in AIX releases 4.3 and newer the native
63dlopen interface of AIX instead of the old emulated interface. This
64change will probably break backward compatibility with compiled
65modules. The change was made to make Perl more compliant with other
66applications like modperl which are using the AIX native interface.
67
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68=head2 Attributes for C<my> variables now handled at run-time.
69
70The C<my EXPR : ATTRS> syntax now applies variable attributes at
71run-time. (Subroutine and C<our> variables still get attributes applied
72at compile-time.) See L<attributes> for additional details. In particular,
73however, this allows variable attributes to be useful for C<tie> interfaces,
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74which was a deficiency of earlier releases. Note that the new semantics
75doesn't work with the Attribute::Handlers module (as of version 0.76).
95f0a2f1 76
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77=head2 Socket Extension Dynamic in VMS
78
79The Socket extension is now dynamically loaded instead of being
80statically built in. This may or may not be a problem with ancient
81TCP/IP stacks of VMS: we do not know since we weren't able to test
82Perl in such configurations.
83
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84=head2 IEEE-format Floating Point Default on OpenVMS Alpha
85
86Perl now uses IEEE format (T_FLOAT) as the default internal floating
87point format on OpenVMS Alpha, potentially breaking binary compatibility
88with external libraries or existing data. G_FLOAT is still available as
89a configuration option. The default on VAX (D_FLOAT) has not changed.
90
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91=head2 Different Definition of the Unicode Character Classes \p{In...}
92
93As suggested by the Unicode consortium, the Unicode character classes
94now prefer I<scripts> as opposed to I<blocks> (as defined by Unicode);
95in Perl, when the C<\p{In....}> and the C<\p{In....}> regular expression
96constructs are used. This has changed the definition of some of those
97character classes.
98
99The difference between scripts and blocks is that scripts are the
100glyphs used by a language or a group of languages, while the blocks
101are more artificial groupings of 256 characters based on the Unicode
102numbering.
103
104In general this change results in more inclusive Unicode character
105classes, but changes to the other direction also do take place:
106for example while the script C<Latin> includes all the Latin
107characters and their various diacritic-adorned versions, it
108does not include the various punctuation or digits (since they
109are not solely C<Latin>).
110
111Changes in the character class semantics may have happened if a script
112and a block happen to have the same name, for example C<Hebrew>.
113In such cases the script wins and C<\p{InHebrew}> now means the script
114definition of Hebrew. The block definition in still available,
115though, by appending C<Block> to the name: C<\p{InHebrewBlock}> means
116what C<\p{InHebrew}> meant in perl 5.6.0. For the full list
117of affected character classes, see L<perlunicode/Blocks>.
118
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119=head2 Perl Parser Stress Tested
120
121The Perl parser has been stress tested using both random input and
122Markov chain input and the few found crashes and lockups have been
123fixed.
124
c2e23569 125=head2 REF(...) Instead Of SCALAR(...)
77c8cf41 126
057b7f2b 127A reference to a reference now stringifies as "REF(0x81485ec)" instead
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128of "SCALAR(0x81485ec)" in order to be more consistent with the return
129value of ref().
77c8cf41 130
c2e23569 131=head2 Deprecations
77c8cf41 132
61947107 133=over 4
77c8cf41 134
61947107 135=item *
f39f21d8 136
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137The semantics of bless(REF, REF) were unclear and until someone proves
138it to make some sense, it is forbidden.
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139
140=item *
141
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142The obsolete chat2 library that should never have been allowed
143to escape the laboratory has been decommissioned.
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144
145=item *
146
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147The very dusty examples in the eg/ directory have been removed.
148Suggestions for new shiny examples welcome but the main issue is that
149the examples need to be documented, tested and (most importantly)
150maintained.
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151
152=item *
153
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154The (bogus) escape sequences \8 and \9 now give an optional warning
155("Unrecognized escape passed through"). There is no need to \-escape
156any C<\w> character.
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157
158=item *
159
c2e23569 160The list of filenames from glob() (or <...>) is now by default sorted
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161alphabetically to be csh-compliant (which is what happened before
162in most UNIX platforms). (bsd_glob() does still sort platform
c2e23569 163natively, ASCII or EBCDIC, unless GLOB_ALPHASORT is specified.)
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164
165=item *
166
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167Spurious syntax errors generated in certain situations, when glob()
168caused File::Glob to be loaded for the first time, have been fixed.
169
170=item *
171
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172Although "you shouldn't do that", it was possible to write code that
173depends on Perl's hashed key order (Data::Dumper does this). The new
174algorithm "One-at-a-Time" produces a different hashed key order.
175More details are in L</"Performance Enhancements">.
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176
177=item *
178
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179lstat(FILEHANDLE) now gives a warning because the operation makes no sense.
180In future releases this may become a fatal error.
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181
182=item *
183
057b7f2b 184The C<package;> syntax (C<package> without an argument) has been
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185deprecated. Its semantics were never that clear and its
186implementation even less so. If you have used that feature to
187disallow all but fully qualified variables, C<use strict;> instead.
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188
189=item *
190
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191The unimplemented POSIX regex features [[.cc.]] and [[=c=]] are still
192recognised but now cause fatal errors. The previous behaviour of
193ignoring them by default and warning if requested was unacceptable
194since it, in a way, falsely promised that the features could be used.
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195
196=item *
197
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198The current user-visible implementation of pseudo-hashes (the weird
199use of the first array element) is deprecated starting from Perl 5.8.0
200and will be removed in Perl 5.10.0, and the feature will be
201implemented differently. Not only is the current interface rather
202ugly, but the current implementation slows down normal array and hash
203use quite noticeably. The C<fields> pragma interface will remain
204available.
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205
206=item *
207
aecce728 208The syntaxes C<< @a->[...] >> and C<< %h->{...} >> have now been deprecated.
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209
210=item *
211
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212After years of trying the suidperl is considered to be too complex to
213ever be considered truly secure. The suidperl functionality is likely
214to be removed in a future release.
215
216=item *
217
218The long deprecated uppercase aliases for the string comparison
219operators (EQ, NE, LT, LE, GE, GT) have now been removed.
220
221=item *
222
223The tr///C and tr///U features have been removed and will not return;
224the interface was a mistake. Sorry about that. For similar
225functionality, see pack('U0', ...) and pack('C0', ...).
f39f21d8 226
420cdfc1
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227=item *
228
229Earlier Perls treated "sub foo (@bar)" as equivalent to "sub foo (@)".
230The prototypes are now checked at compile-time for invalid characters.
231An optional warning is generated ("Illegal character in prototype...")
232but this may be upgraded to a fatal error in a future release.
233
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234=back
235
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236=head1 Core Enhancements
237
77c8cf41 238=head2 PerlIO is Now The Default
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239
240=over 4
241
242=item *
243
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244IO is now by default done via PerlIO rather than system's "stdio".
245PerlIO allows "layers" to be "pushed" onto a file handle to alter the
246handle's behaviour. Layers can be specified at open time via 3-arg
247form of open:
f39f21d8 248
77c8cf41 249 open($fh,'>:crlf :utf8', $path) || ...
f39f21d8 250
77c8cf41 251or on already opened handles via extended C<binmode>:
f39f21d8 252
77c8cf41 253 binmode($fh,':encoding(iso-8859-7)');
f39f21d8 254
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255The built-in layers are: unix (low level read/write), stdio (as in
256previous Perls), perlio (re-implementation of stdio buffering in a
257portable manner), crlf (does CRLF <=> "\n" translation as on Win32,
258but available on any platform). A mmap layer may be available if
259platform supports it (mostly UNIXes).
f39f21d8 260
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261Layers to be applied by default may be specified via the 'open' pragma.
262
263See L</"Installation and Configuration Improvements"> for the effects
264of PerlIO on your architecture name.
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265
266=item *
267
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268File handles can be marked as accepting Perl's internal encoding of Unicode
269(UTF-8 or UTF-EBCDIC depending on platform) by a pseudo layer ":utf8" :
f39f21d8 270
77c8cf41 271 open($fh,">:utf8","Uni.txt");
f39f21d8 272
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273Note for EBCDIC users: the pseudo layer ":utf8" is erroneously named
274for you since it's not UTF-8 what you will be getting but instead
275UTF-EBCDIC. See L<perlunicode>, L<utf8>, and
276http://www.unicode.org/unicode/reports/tr16/ for more information.
277In future releases this naming may change.
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278
279=item *
280
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281File handles can translate character encodings from/to Perl's internal
282Unicode form on read/write via the ":encoding()" layer.
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283
284=item *
285
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286File handles can be opened to "in memory" files held in Perl scalars via:
287
288 open($fh,'>', \$variable) || ...
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289
290=item *
291
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292Anonymous temporary files are available without need to
293'use FileHandle' or other module via
f39f21d8 294
77c8cf41 295 open($fh,"+>", undef) || ...
f39f21d8 296
77c8cf41 297That is a literal undef, not an undefined value.
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298
299=item *
300
77c8cf41 301The list form of C<open> is now implemented for pipes (at least on UNIX):
f39f21d8 302
77c8cf41 303 open($fh,"-|", 'cat', '/etc/motd')
f39f21d8 304
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305creates a pipe, and runs the equivalent of exec('cat', '/etc/motd') in
306the child process.
f39f21d8 307
e1f170bd 308=back
f39f21d8 309
3e33716f 310=head2 Safe Signals
f39f21d8 311
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312Perl used to be fragile in that signals arriving at inopportune moments
313could corrupt Perl's internal state. Now Perl postpones handling of
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314signals until it's safe (between opcodes).
315
316This change may have surprising side effects because signals no more
317interrupt Perl instantly. Perl will now first finish whatever it was
318doing, like finishing an internal operation (like sort()) or an
319external operation (like an I/O operation), and only then look at any
320arrived signals (and before starting the next operation). No more corrupt
321internal state since the current operation is always finished first,
322but the signal may take more time to get heard.
f39f21d8 323
e1f170bd 324=head2 Unicode Overhaul
f39f21d8 325
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326Unicode in general should be now much more usable than in Perl 5.6.0
327(or even in 5.6.1). Unicode can be used in hash keys, Unicode in
328regular expressions should work now, Unicode in tr/// should work now,
329Unicode in I/O should work now.
f39f21d8 330
e1f170bd 331=over 4
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332
333=item *
334
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335The Unicode Character Database coming with Perl has been upgraded
336to Unicode 3.1.1. For more information, see http://www.unicode.org/.
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337
338=item *
339
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340For developers interested in enhancing Perl's Unicode capabilities:
341almost all the UCD files are included with the Perl distribution in
e1f170bd 342the lib/unicore subdirectory. The most notable omission, for space
77c8cf41 343considerations, is the Unihan database.
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344
345=item *
346
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347The Unicode character classes \p{Blank} and \p{SpacePerl} have been
348added. "Blank" is like C isblank(), that is, it contains only
349"horizontal whitespace" (the space character is, the newline isn't),
350and the "SpacePerl" is the Unicode equivalent of C<\s> (\p{Space}
351isn't, since that includes the vertical tabulator character, whereas
352C<\s> doesn't.)
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353
354=back
355
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356=head2 Understanding of Numbers
357
358In general a lot of fixing has happened in the area of Perl's
359understanding of numbers, both integer and floating point. Since in
360many systems the standard number parsing functions like C<strtoul()>
361and C<atof()> seem to have bugs, Perl tries to work around their
362deficiencies. This results hopefully in more accurate numbers.
f39f21d8 363
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364Perl now tries internally to use integer values in numeric conversions
365and basic arithmetics (+ - * /) if the arguments are integers, and
366tries also to keep the results stored internally as integers.
057b7f2b 367This change leads to often slightly faster and always less lossy
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368arithmetics. (Previously Perl always preferred floating point numbers
369in its math.)
370
371=head2 Miscellaneous Enhancements
372
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373=over 4
374
375=item *
376
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377AUTOLOAD is now lvaluable, meaning that you can add the :lvalue attribute
378to AUTOLOAD subroutines and you can assign to the AUTOLOAD return value.
379
380=item *
381
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382C<perl -d:Module=arg,arg,arg> now works (previously one couldn't pass
383in multiple arguments.)
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384
385=item *
386
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387END blocks are now run even if you exit/die in a BEGIN block.
388Internally, the execution of END blocks is now controlled by
389PL_exit_flags & PERL_EXIT_DESTRUCT_END. This enables the new
390behaviour for Perl embedders. This will default in 5.10. See
391L<perlembed>.
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392
393=item *
394
e1f170bd 395Formats now support zero-padded decimal fields.
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396
397=item *
398
77c8cf41 399Lvalue subroutines can now return C<undef> in list context.
44da0e71 400However, the lvalue subroutine feature still remains experimental.
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401
402=item *
403
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404A new special regular expression variable has been introduced:
405C<$^N>, which contains the most-recently closed group (submatch).
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406
407=item *
408
61947107 409C<no Module;> now works even if there is no "sub unimport" in the Module.
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410
411=item *
412
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413The numerical comparison operators return C<undef> if either operand
414is a NaN. Previously the behaviour was unspecified.
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415
416=item *
417
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418The following builtin functions are now overridable: each(), keys(),
419pop(), push(), shift(), splice(), unshift().
420
421=item *
422
61947107 423C<pack('U0a*', ...)> can now be used to force a string to UTF8.
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424
425=item *
426
61947107 427my __PACKAGE__ $obj now works.
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428
429=item *
430
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431The printf() and sprintf() now support parameter reordering using the
432C<%\d+\$> and C<*\d+\$> syntaxes. For example
433
434 print "%2\$s %1\$s\n", "foo", "bar";
435
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436will print "bar foo\n". This feature helps in writing
437internationalised software, and in general when the order
438of the parameters can vary.
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439
440=item *
441
e1f170bd 442prototype(\&) is now available.
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443
444=item *
445
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446prototype(\[$@%&]) is now available to implicitly create references
447(useful for example if you want to emulate the tie() interface).
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448
449=item *
450
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451untie() will now call an UNTIE() hook if it exists. See L<perltie>
452for details.
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453
454=item *
455
456L<utime> now supports C<utime undef, undef, @files> to change the
457file timestamps to the current time.
458
459=item *
460
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461The rules for allowing underscores (underbars) in numeric constants
462have been relaxed and simplified: now you can have an underscore
463simply B<between digits>.
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464
465=back
466
77c8cf41 467=head1 Modules and Pragmata
f39f21d8 468
1e13d81f 469=head2 New Modules and Pragmata
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470
471=over 4
472
473=item *
474
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475C<Attribute::Handlers> allows a class to define attribute handlers.
476
477 package MyPack;
478 use Attribute::Handlers;
479 sub Wolf :ATTR(SCALAR) { print "howl!\n" }
480
481 # later, in some package using or inheriting from MyPack...
482
483 my MyPack $Fluffy : Wolf; # the attribute handler Wolf will be called
484
485Both variables and routines can have attribute handlers. Handlers can
486be specific to type (SCALAR, ARRAY, HASH, or CODE), or specific to the
487exact compilation phase (BEGIN, CHECK, INIT, or END).
488
489=item *
490
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491B<B::Concise> is a new compiler backend for walking the Perl syntax
492tree, printing concise info about ops, from Stephen McCamant. The
493output is highly customisable. See L<B::Concise>.
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494
495=item *
496
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497C<Class::ISA> for reporting the search path for a class's ISA tree,
498by Sean Burke, has been added. See L<Class::ISA>.
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499
500=item *
501
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502C<Cwd> has now a split personality: if possible, an XS extension is
503used, (this will hopefully be faster, more secure, and more robust)
504but if not possible, the familiar Perl implementation is used.
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505
506=item *
507
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508C<Devel::PPPort>, originally from Kenneth Albanowski and now
509maintained by Paul Marquess, has been added. It is primarily used
510by C<h2xs> to enhance portability of of XS modules between different
511versions of Perl.
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512
513=item *
514
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515C<Digest>, frontend module for calculating digests (checksums), from
516Gisle Aas, has been added. See L<Digest>.
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517
518=item *
519
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520C<Digest::MD5> for calculating MD5 digests (checksums) as defined in
521RFC 1321, from Gisle Aas, has been added. See L<Digest::MD5>.
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522
523 use Digest::MD5 'md5_hex';
524
525 $digest = md5_hex("Thirsty Camel");
526
527 print $digest, "\n"; # 01d19d9d2045e005c3f1b80e8b164de1
528
61947107 529NOTE: the C<MD5> backward compatibility module is deliberately not
e1f170bd 530included since its further use is discouraged.
f39f21d8 531
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532=item *
533
61947107 534C<Encode>, by Nick Ing-Simmons, provides a mechanism to translate
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535between different character encodings. Support for Unicode,
536ISO-8859-*, ASCII, CP*, KOI8-R, and three variants of EBCDIC are
537compiled in to the module. Several other encodings (like Japanese,
538Chinese, and MacIntosh encodings) are included and will be loaded at
61947107 539runtime. See L<Encode>.
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540
541Any encoding supported by Encode module is also available to the
542":encoding()" layer if PerlIO is used.
543
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544=item *
545
546C<I18N::Langinfo> can be use to query locale information.
547See L<I18N::Langinfo>.
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548
549=item *
550
61947107 551C<I18N::LangTags> has functions for dealing with RFC3066-style
bea4d472 552language tags, by Sean Burke. See L<I18N::LangTags>.
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553
554=item *
555
556C<ExtUtils::Constant> is a new tool for extension writers for
557generating XS code to import C header constants, by Nicholas Clark.
558See L<ExtUtils::Constant>.
559
560=item *
561
562C<Filter::Simple> is an easy-to-use frontend to Filter::Util::Call,
563from Damian Conway. See L<Filter::Simple>.
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564
565 # in MyFilter.pm:
566
567 package MyFilter;
568
569 use Filter::Simple sub {
570 while (my ($from, $to) = splice @_, 0, 2) {
571 s/$from/$to/g;
572 }
573 };
574
575 1;
576
577 # in user's code:
578
579 use MyFilter qr/red/ => 'green';
580
581 print "red\n"; # this code is filtered, will print "green\n"
582 print "bored\n"; # this code is filtered, will print "bogreen\n"
583
584 no MyFilter;
585
586 print "red\n"; # this code is not filtered, will print "red\n"
587
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588=item *
589
590C<File::Temp> allows one to create temporary files and directories in
591an easy, portable, and secure way, by Tim Jenness. See L<File::Temp>.
592
593=item *
594
595C<Filter::Util::Call> provides you with the framework to write
596I<Source Filters> in Perl, from Paul Marquess. For most uses the
597frontend Filter::Simple is to be preferred. See L<Filter::Util::Call>.
598
599=item *
600
601L<libnet> is a collection of perl5 modules related to network
602programming, from Graham Barr. See L<Net::FTP>, L<Net::NNTP>,
603L<Net::Ping>, L<Net::POP3>, L<Net::SMTP>, and L<Net::Time>.
604
605Perl installation leaves libnet unconfigured, use F<libnetcfg> to configure.
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606
607=item *
608
61947107 609C<List::Util> is a selection of general-utility list subroutines, like
bea4d472 610sum(), min(), first(), and shuffle(), by Graham Barr. See L<List::Util>.
f39f21d8
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611
612=item *
613
61947107
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614C<Locale::Constants>, C<Locale::Country>, C<Locale::Currency>, and
615C<Locale::Language>, from Neil Bowers, have been added. They provide the
616codes for various locale standards, such as "fr" for France, "usd" for
617US Dollar, and "jp" for Japanese.
f39f21d8
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618
619 use Locale::Country;
620
621 $country = code2country('jp'); # $country gets 'Japan'
622 $code = country2code('Norway'); # $code gets 'no'
623
624See L<Locale::Constants>, L<Locale::Country>, L<Locale::Currency>,
61947107
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625and L<Locale::Language>.
626
627=item *
628
629C<Locale::Maketext> is localization framework from Sean Burke. See
630L<Locale::Maketext>, and L<Locale::Maketext::TPJ13>. The latter is an
631article about software localization, originally published in The Perl
632Journal #13, republished here with kind permission.
633
634=item *
635
636C<Memoize> can make your functions faster by trading space for time,
637from Mark-Jason Dominus. See L<Memoize>.
f39f21d8
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638
639=item *
640
61947107
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641C<MIME::Base64> allows you to encode data in base64, from Gisle Aas,
642as defined in RFC 2045 - I<MIME (Multipurpose Internet Mail
643Extensions)>.
f39f21d8
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644
645 use MIME::Base64;
646
647 $encoded = encode_base64('Aladdin:open sesame');
648 $decoded = decode_base64($encoded);
649
650 print $encoded, "\n"; # "QWxhZGRpbjpvcGVuIHNlc2FtZQ=="
651
61947107 652See L<MIME::Base64>.
f39f21d8
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653
654=item *
655
61947107
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656C<MIME::QuotedPrint> allows you to encode data in quoted-printable
657encoding, as defined in RFC 2045 - I<MIME (Multipurpose Internet Mail
658Extensions)>, from Gisle Aas.
f39f21d8
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659
660 use MIME::QuotedPrint;
661
662 $encoded = encode_qp("Smiley in Unicode: \x{263a}");
663 $decoded = decode_qp($encoded);
664
665 print $encoded, "\n"; # "Smiley in Unicode: =263A"
666
667MIME::QuotedPrint has been enhanced to provide the basic methods
668necessary to use it with PerlIO::Via as in :
669
670 use MIME::QuotedPrint;
057b7f2b 671 open($fh,">Via(MIME::QuotedPrint)",$path);
f39f21d8 672
61947107 673See L<MIME::QuotedPrint>.
f39f21d8
JH
674
675=item *
676
61947107
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677C<NEXT> is pseudo-class for method redispatch, from Damian Conway.
678See L<NEXT>.
f39f21d8
JH
679
680=item *
681
1e13d81f
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682C<open> is a new pragma for setting the default I/O disciplines
683for open().
684
685=item *
686
61947107
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687C<PerlIO::Scalar> provides the implementation of IO to "in memory"
688Perl scalars as discussed above, from Nick Ing-Simmons. It also
689serves as an example of a loadable PerlIO layer. Other future
690possibilities include PerlIO::Array and PerlIO::Code.
691See L<PerlIO::Scalar>.
692
693=item *
694
695C<PerlIO::Via> acts as a PerlIO layer and wraps PerlIO layer
696functionality provided by a class (typically implemented in perl
697code), from Nick Ing-Simmons.
f39f21d8
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698
699 use MIME::QuotedPrint;
057b7f2b 700 open($fh,">Via(MIME::QuotedPrint)",$path);
f39f21d8
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701
702This will automatically convert everything output to C<$fh>
61947107 703to Quoted-Printable. See L<PerlIO::Via>.
f39f21d8
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704
705=item *
706
1e13d81f 707C<Pod::ParseLink>, by Russ Allbery, has been added,
95f0a2f1 708to parse LZ<><> links in pods as described in the new
1e13d81f
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709perlpodspec.
710
711=item *
712
61947107 713C<Pod::Text::Overstrike>, by Joe Smith, has been added.
f39f21d8 714It converts POD data to formatted overstrike text.
61947107 715See L<Pod::Text::Overstrike>.
f39f21d8
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716
717=item *
718
61947107
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719C<Scalar::Util> is a selection of general-utility scalar subroutines,
720like blessed(), reftype(), and tainted(). See L<Scalar::Util>.
721
722=item *
723
1e13d81f
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724C<sort> is a new pragma for controlling the behaviour of sort().
725
726=item *
727
61947107
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728C<Storable> gives persistence to Perl data structures by allowing the
729storage and retrieval of Perl data to and from files in a fast and
730compact binary format, from Raphael Manfredi. See L<Storable>.
731
732=item *
733
734C<Switch>, from Damian Conway, has been added. Just by saying
f39f21d8
JH
735
736 use Switch;
737
738you have C<switch> and C<case> available in Perl.
739
740 use Switch;
741
742 switch ($val) {
743
744 case 1 { print "number 1" }
745 case "a" { print "string a" }
746 case [1..10,42] { print "number in list" }
747 case (@array) { print "number in list" }
748 case /\w+/ { print "pattern" }
749 case qr/\w+/ { print "pattern" }
750 case (%hash) { print "entry in hash" }
751 case (\%hash) { print "entry in hash" }
752 case (\&sub) { print "arg to subroutine" }
753 else { print "previous case not true" }
754 }
755
61947107
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756See L<Switch>.
757
758=item *
759
760C<Test::More> is yet another framework for writing test scripts,
761more extensive than Test::Simple, by Michael Schwern. See L<Test::More>.
762
763=item *
764
aecce728 765C<Test::Simple> has basic utilities for writing tests, by Michael
61947107 766Schwern. See L<Test::Simple>.
77c8cf41
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767
768=item *
769
61947107
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770C<Text::Balanced> has been added, for extracting delimited text
771sequences from strings, from Damian Conway.
77c8cf41
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772
773 use Text::Balanced 'extract_delimited';
774
775 ($a, $b) = extract_delimited("'never say never', he never said", "'", '');
776
777$a will be "'never say never'", $b will be ', he never said'.
778
779In addition to extract_delimited() there are also extract_bracketed(),
780extract_quotelike(), extract_codeblock(), extract_variable(),
781extract_tagged(), extract_multiple(), gen_delimited_pat(), and
782gen_extract_tagged(). With these you can implement rather advanced
61947107 783parsing algorithms. See L<Text::Balanced>.
77c8cf41
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784
785=item *
786
c2e23569 787C<threads> is an interface to interpreter threads, by Arthur Bergman.
61947107 788Interpreter threads (ithreads) is the new thread model introduced in
c2e23569
JH
789Perl 5.6 but only available as an internal interface for extension
790writers (and for Win32 Perl for C<fork()> emulation). See L<threads>.
77c8cf41
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791
792=item *
793
61947107
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794C<threads::shared> allows data sharing for interpreter threads, from
795Arthur Bergman. In the ithreads model any data sharing between
796threads must be explicit, as opposed to the old 5.005 thread model
797where data sharing was implicit. See L<threads::shared>.
77c8cf41
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798
799=item *
800
61947107 801C<Tie::RefHash::Nestable>, by Edward Avis, allows storing hash
ba370e9b
JH
802references (unlike the standard Tie::RefHash) The module is contained
803within Tie::RefHash, see L<Tie::RefHash>.
77c8cf41
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804
805=item *
806
61947107
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807C<Time::HiRes> provides high resolution timing (ualarm, usleep,
808and gettimeofday), from Douglas E. Wegscheid. See L<Time::HiRes>.
77c8cf41
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809
810=item *
811
61947107
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812C<Unicode::UCD> offers a querying interface to the Unicode Character
813Database. See L<Unicode::UCD>.
77c8cf41
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814
815=item *
816
61947107
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817C<Unicode::Collate> implements the UCA (Unicode Collation Algorithm)
818for sorting Unicode strings, by SADAHIRO Tomoyuki. See L<Unicode::Collate>.
77c8cf41
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819
820=item *
821
61947107
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822C<Unicode::Normalize> implements the various Unicode normalization
823forms, by SADAHIRO Tomoyuki. See L<Unicode::Normalize>.
77c8cf41
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824
825=item *
826
61947107
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827C<XS::Typemap>, by Tim Jenness, is a test extension that exercises XS
828typemaps. Nothing gets installed but for extension writers the code
829is worth studying.
77c8cf41
JH
830
831=back
832
833=head2 Updated And Improved Modules and Pragmata
834
835=over 4
836
837=item *
838
61947107
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839The following independently supported modules have been updated to the
840newest versions from CPAN: CGI, CPAN, DB_File, File::Spec, File::Temp,
841Getopt::Long, Math::BigFloat, Math::BigInt, the podlators bundle
842(Pod::Man, Pod::Text), Pod::LaTeX, Pod::Parser, Storable,
843Term::ANSIColor, Test, Text-Tabs+Wrap.
77c8cf41
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844
845=item *
846
61947107 847The attributes::reftype() now works on tied arguments.
77c8cf41
JH
848
849=item *
850
057b7f2b 851AutoLoader can now be disabled with C<no AutoLoader;>.
77c8cf41
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852
853=item *
854
1e13d81f
JH
855B::Deparse has been significantly enhanced. It now can deparse almost
856all of the standard test suite (so that the tests still succeed).
857There is a make target "test.deparse" for trying this out.
77c8cf41
JH
858
859=item *
860
1e13d81f 861Class::Struct can now define the classes in compile time.
77c8cf41
JH
862
863=item *
864
1e13d81f
JH
865Class::Struct now assigns the array/hash element if the accessor
866is called with an array/hash element as the B<sole> argument.
77c8cf41
JH
867
868=item *
869
1e13d81f 870Data::Dumper has now an option to sort hashes.
77c8cf41
JH
871
872=item *
873
1e13d81f
JH
874Data::Dumper has now an option to dump code references
875using B::Deparse.
77c8cf41
JH
876
877=item *
878
44da0e71
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879DB_File now supports newer Berkeley DB versions, among
880other improvements.
881
882=item *
883
1e13d81f
JH
884The English module can now be used without the infamous performance
885hit by saying
77c8cf41 886
1e13d81f 887 use English '-no_performance_hit';
77c8cf41 888
1e13d81f
JH
889(Assuming, of course, that one doesn't need the troublesome variables
890C<$`>, C<$&>, or C<$'>.) Also, introduced C<@LAST_MATCH_START> and
891C<@LAST_MATCH_END> English aliases for C<@-> and C<@+>.
77c8cf41
JH
892
893=item *
894
1e13d81f
JH
895Fcntl, Socket, and Sys::Syslog have been rewritten to use the
896new-style constant dispatch section (see L<ExtUtils::Constant>).
897This means that they will be more robust and hopefully faster.
77c8cf41
JH
898
899=item *
900
44da0e71
JH
901File::Find now chdir()s correctly when chasing symbolic links.
902
903=item *
904
1e13d81f
JH
905File::Find now has pre- and post-processing callbacks. It also
906correctly changes directories when chasing symbolic links. Callbacks
907(naughtily) exiting with "next;" instead of "return;" now work.
61947107
JH
908
909=item *
910
1e13d81f
JH
911File::Find is now (again) reentrant. It also has been made
912more portable.
77c8cf41 913
61947107
JH
914=item *
915
1e13d81f
JH
916File::Glob::glob() renamed to File::Glob::bsd_glob() to avoid
917prototype mismatch with CORE::glob().
61947107
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918
919=item *
920
921File::Glob now supports C<GLOB_LIMIT> constant to limit the size of
922the returned list of filenames.
77c8cf41
JH
923
924=item *
925
926Devel::Peek now has an interface for the Perl memory statistics
927(this works only if you are using perl's malloc, and if you have
928compiled with debugging).
929
930=item *
931
1e13d81f
JH
932IPC::Open3 now allows the use of numeric file descriptors.
933
934=item *
935
77c8cf41
JH
936IO::Socket has now atmark() method, which returns true if the socket
937is positioned at the out-of-band mark. The method is also exportable
938as a sockatmark() function.
939
940=item *
941
942IO::Socket::INET has support for ReusePort option (if your platform
943supports it). The Reuse option now has an alias, ReuseAddr. For clarity
944you may want to prefer ReuseAddr.
945
946=item *
947
61947107
JH
948IO::Socket::INET now supports C<LocalPort> of zero (usually meaning
949that the operating system will make one up.)
77c8cf41
JH
950
951=item *
952
1e13d81f
JH
953use lib now works identically to @INC. Removing directories
954with 'no lib' now works.
955
956=item *
957
958Math::BigFloat and Math::BigInt have undergone a full rewrite.
959They are now magnitudes faster, and they support various
61947107 960bignum libraries such as GMP and PARI as their backends.
f39f21d8
JH
961
962=item *
963
44da0e71
JH
964Math::Complex handles inf, NaN etc., better.
965
966=item *
967
61947107
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968Net::Ping has been enhanced. There is now "external" protocol which
969uses Net::Ping::External module which runs external ping(1) and parses
44da0e71 970the output. A version of Net::Ping::External is available in CPAN.
f39f21d8 971
77c8cf41 972=item *
f39f21d8 973
da6838c8 974POSIX::sigaction() is now much more flexible and robust.
61947107
JH
975You can now install coderef handlers, 'DEFAULT', and 'IGNORE'
976handlers, installing new handlers was not atomic.
f39f21d8
JH
977
978=item *
979
da6838c8 980In Safe the C<%INC> now localised in a Safe compartment so that
76663d67
JH
981use/require work.
982
983=item *
984
44da0e71
JH
985In SDBM_File on dosish platforms, some keys went missing because of
986lack of support for files with "holes". A workaround for the problem
987has been added.
988
989=item *
990
da6838c8 991In Search::Dict one can now have a pre-processing hook for the
76663d67 992lines being searched.
1e13d81f
JH
993
994=item *
995
996The Shell module now has an OO interface.
997
998=item *
999
61947107 1000The Test module has been significantly enhanced.
f39f21d8
JH
1001
1002=item *
1003
da6838c8 1004The vars pragma now supports declaring fully qualified variables.
77c8cf41 1005(Something that C<our()> does not and will not support.)
f39f21d8 1006
888aee59
JH
1007=item *
1008
61947107
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1009The utf8:: name space (as in the pragma) provides various
1010Perl-callable functions to provide low level access to Perl's
1011internal Unicode representation. At the moment only length()
1012has been implemented.
888aee59 1013
f39f21d8
JH
1014=back
1015
77c8cf41 1016=head1 Utility Changes
f39f21d8
JH
1017
1018=over 4
1019
1020=item *
1021
61947107 1022Emacs perl mode (emacs/cperl-mode.el) has been updated to version
77c8cf41 10234.31.
f39f21d8
JH
1024
1025=item *
1026
61947107 1027F<emacs/e2ctags.pl> is now much faster.
f39f21d8
JH
1028
1029=item *
1030
1e13d81f
JH
1031C<h2ph> now supports C trigraphs.
1032
1033=item *
1034
1035C<h2xs> now produces a template README.
f39f21d8 1036
77c8cf41
JH
1037=item *
1038
1e13d81f
JH
1039C<h2xs> now uses C<Devel::PPort> for better portability between
1040different versions of Perl.
f39f21d8
JH
1041
1042=item *
1043
1e13d81f 1044C<h2xs> uses the new L<ExtUtils::Constant> module which will affect
61947107
JH
1045newly created extensions that define constants. Since the new code is
1046more correct (if you have two constants where the first one is a
1047prefix of the second one, the first constant B<never> gets defined),
1048less lossy (it uses integers for integer constant, as opposed to the
1049old code that used floating point numbers even for integer constants),
1050and slightly faster, you might want to consider regenerating your
1051extension code (the new scheme makes regenerating easy).
1052L<h2xs> now also supports C trigraphs.
f39f21d8
JH
1053
1054=item *
1055
1e13d81f 1056C<libnetcfg> has been added to configure the libnet.
f39f21d8
JH
1057
1058=item *
1059
1e13d81f 1060C<perlbug> is now much more robust. It also sends the bug report to
61947107 1061perl.org, not perl.com.
f39f21d8
JH
1062
1063=item *
1064
1e13d81f 1065C<perlcc> has been rewritten and its user interface (that is,
61947107 1066command line) is much more like that of the UNIX C compiler, cc.
44da0e71 1067(The perlbc tools has been removed. Use C<perlcc -B> instead.)
f39f21d8
JH
1068
1069=item *
1070
aecce728
JH
1071C<perlivp> is a new Installation Verification Procedure utility
1072for running any time after installing Perl.
f39f21d8
JH
1073
1074=item *
1075
1e13d81f 1076C<pod2html> now allows specifying a cache directory.
f39f21d8
JH
1077
1078=item *
1079
1e13d81f
JH
1080C<s2p> has been completely rewritten in Perl. (It is in fact a full
1081implementation of sed in Perl: you can use the sed functionality by
1082using the C<psed> utility.)
61947107
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1083
1084=item *
1085
1e13d81f 1086C<xsubpp> now understands POD documentation embedded in the *.xs files.
f39f21d8
JH
1087
1088=item *
1089
1e13d81f 1090C<xsubpp> now supports OUT keyword.
f39f21d8
JH
1091
1092=back
1093
77c8cf41 1094=head1 New Documentation
f39f21d8
JH
1095
1096=over 4
1097
1098=item *
1099
77c8cf41
JH
1100perl56delta details the changes between the 5.005 release and the
11015.6.0 release.
f39f21d8
JH
1102
1103=item *
1104
61947107
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1105perlclib documents the internal replacements for standard C library
1106functions. (Interesting only for extension writers and Perl core
1107hackers.)
1108
1109=item *
1110
77c8cf41 1111perldebtut is a Perl debugging tutorial.
f39f21d8 1112
77c8cf41 1113=item *
f39f21d8 1114
77c8cf41 1115perlebcdic contains considerations for running Perl on EBCDIC platforms.
f39f21d8 1116
77c8cf41
JH
1117=item *
1118
888aee59
JH
1119perlintro is a gentle introduction to Perl.
1120
1121=item *
1122
61947107
JH
1123perliol documents the internals of PerlIO with layers.
1124
1125=item *
1126
888aee59
JH
1127perlmodstyle is a style guide for writing modules.
1128
1129=item *
1130
77c8cf41 1131perlnewmod tells about writing and submitting a new module.
f39f21d8
JH
1132
1133=item *
1134
34babc16
JH
1135perlpacktut is a pack() tutorial.
1136
1137=item *
1138
888aee59
JH
1139perlpod has been rewritten to be clearer and to record the best
1140practices gathered over the years.
1141
1142=item *
1143
057b7f2b 1144perlpodspec is a more formal specification of the pod format,
888aee59
JH
1145mainly of interest for writers of pod applications, not to
1146people writing in pod.
1147
1148=item *
1149
77c8cf41 1150perlretut is a regular expression tutorial.
f39f21d8
JH
1151
1152=item *
1153
77c8cf41
JH
1154perlrequick is a regular expressions quick-start guide.
1155Yes, much quicker than perlretut.
f39f21d8 1156
77c8cf41 1157=item *
f39f21d8 1158
61947107
JH
1159perltodo has been updated.
1160
1161=item *
1162
888aee59 1163perltootc has been renamed as perltooc (to not to conflict
61947107 1164with perltoot in filesystems restricted to "8.3" names)
888aee59
JH
1165
1166=item *
1167
1168perluniintro is an introduction to using Unicode in Perl
1169(perlunicode is more of a reference)
1170
1171=item *
1172
77c8cf41
JH
1173perlutil explains the command line utilities packaged with the Perl
1174distribution.
1175
1176=back
f39f21d8 1177
61947107
JH
1178The following platform-specific documents are available before
1179the installation as README.I<platform>, and after the installation
1180as perlI<platform>:
f39f21d8 1181
61947107
JH
1182 perlaix perlamiga perlapollo perlbeos perlbs2000
1183 perlce perlcygwin perldgux perldos perlepoc perlhpux
1184 perlhurd perlmachten perlmacos perlmint perlmpeix
1185 perlnetware perlos2 perlos390 perlplan9 perlqnx perlsolaris
1186 perltru64 perluts perlvmesa perlvms perlvos perlwin32
77c8cf41
JH
1187
1188=over 4
1189
1190=item *
1191
61947107
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1192The documentation for the POSIX-BC platform is called "BS2000", to avoid
1193confusion with the Perl POSIX module.
77c8cf41
JH
1194
1195=item *
1196
61947107
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1197The documentation for the WinCE platform is called "CE", to avoid
1198confusion with the perlwin32 documentation on 8.3-restricted filesystems.
77c8cf41
JH
1199
1200=back
1201
1202=head1 Performance Enhancements
1203
1204=over 4
1205
1206=item *
1207
44da0e71
JH
1208map() could get pathologically slow when the result list it generates
1209is larger than the source list. The performance has been improved for
1210common scenarios.
77c8cf41
JH
1211
1212=item *
1213
e1f170bd
JH
1214sort() has been changed to use primarily mergesort internally as
1215opposed to the earlier quicksort. For very small lists this may
1216result in slightly slower sorting times, but in general the speedup
1217should be at least 20%. Additional bonuses are that the worst case
1218behaviour of sort() is now better (in computer science terms it now
1219runs in time O(N log N), as opposed to quicksort's Theta(N**2)
1220worst-case run time behaviour), and that sort() is now stable
1221(meaning that elements with identical keys will stay ordered as they
1222were before the sort). See the C<sort> pragma for information.
77c8cf41 1223
05e25c75
JH
1224The story in more detail: suppose you want to serve yourself a little
1225slice of Pi.
1226
1227 @digits = ( 3,1,4,1,5,9 );
1228
1229A numerical sort of the digits will yield (1,1,3,4,5,9), as expected.
1230Which C<1> comes first is hard to know, since one C<1> looks pretty
1231much like any other. You can regard this as totally trivial,
1232or somewhat profound. However, if you just want to sort the even
1233digits ahead of the odd ones, then what will
1234
1235 sort { ($a % 2) <=> ($b % 2) } @digits;
1236
1237yield? The only even digit, C<4>, will come first. But how about
1238the odd numbers, which all compare equal? With the quicksort algorithm
1239used to implement Perl 5.6 and earlier, the order of ties is left up
1240to the sort. So, as you add more and more digits of Pi, the order
1241in which the sorted even and odd digits appear will change.
1242and, for sufficiently large slices of Pi, the quicksort algorithm
1243in Perl 5.8 won't return the same results even if reinvoked with the
1244same input. The justification for this rests with quicksort's
1245worst case behavior. If you run
1246
1247 sort { $a <=> $b } ( 1 .. $N , 1 .. $N );
1248
1249(something you might approximate if you wanted to merge two sorted
1250arrays using sort), doubling $N doesn't just double the quicksort time,
1251it I<quadruples> it. Quicksort has a worst case run time that can
1252grow like N**2, so-called I<quadratic> behaviour, and it can happen
1253on patterns that may well arise in normal use. You won't notice this
1254for small arrays, but you I<will> notice it with larger arrays,
1255and you may not live long enough for the sort to complete on arrays
1256of a million elements. So the 5.8 quicksort scrambles large arrays
1257before sorting them, as a statistical defence against quadratic behaviour.
1258But that means if you sort the same large array twice, ties may be
1259broken in different ways.
1260
1261Because of the unpredictability of tie-breaking order, and the quadratic
1262worst-case behaviour, quicksort was I<almost> replaced completely with
1263a stable mergesort. I<Stable> means that ties are broken to preserve
1264the original order of appearance in the input array. So
1265
1266 sort { ($a % 2) <=> ($b % 2) } (3,1,4,1,5,9);
1267
1268will yield (4,3,1,1,5,9), guaranteed. The even and odd numbers
1269appear in the output in the same order they appeared in the input.
1270Mergesort has worst case O(NlogN) behaviour, the best value
1271attainable. And, ironically, this mergesort does particularly
1272well where quicksort goes quadratic: mergesort sorts (1..$N, 1..$N)
1273in O(N) time. But quicksort was rescued at the last moment because
1274it is faster than mergesort on certain inputs and platforms.
1275For example, if you really I<don't> care about the order of even
1276and odd digits, quicksort will run in O(N) time; it's very good
1277at sorting many repetitions of a small number of distinct elements.
1278The quicksort divide and conquer strategy works well on platforms
1279with relatively small, very fast, caches. Eventually, the problem gets
1280whittled down to one that fits in the cache, from which point it
1281benefits from the increased memory speed.
1282
1283Quicksort was rescued by implementing a sort pragma to control aspects
1284of the sort. The B<stable> subpragma forces stable behaviour,
1285regardless of algorithm. The B<_quicksort> and B<_mergesort>
1286subpragmas are heavy-handed ways to select the underlying implementation.
1287The leading C<_> is a reminder that these subpragmas may not survive
1288beyond 5.8. More appropriate mechanisms for selecting the implementation
1289exist, but they wouldn't have arrived in time to save quicksort.
1290
77c8cf41
JH
1291=item *
1292
1293Hashes now use Bob Jenkins "One-at-a-Time" hashing key algorithm
1294(http://burtleburtle.net/bob/hash/doobs.html). This algorithm is
1295reasonably fast while producing a much better spread of values than
1296the old hashing algorithm (originally by Chris Torek, later tweaked by
1297Ilya Zakharevich). Hash values output from the algorithm on a hash of
1298all 3-char printable ASCII keys comes much closer to passing the
1299DIEHARD random number generation tests. According to perlbench, this
1300change has not affected the overall speed of Perl.
1301
1302=item *
1303
1304unshift() should now be noticeably faster.
1305
1306=back
1307
1308=head1 Installation and Configuration Improvements
1309
1310=head2 Generic Improvements
1311
1312=over 4
1313
1314=item *
1315
1316INSTALL now explains how you can configure Perl to use 64-bit
1317integers even on non-64-bit platforms.
1318
1319=item *
1320
1321Policy.sh policy change: if you are reusing a Policy.sh file
1322(see INSTALL) and you use Configure -Dprefix=/foo/bar and in the old
1323Policy $prefix eq $siteprefix and $prefix eq $vendorprefix, all of
1324them will now be changed to the new prefix, /foo/bar. (Previously
1325only $prefix changed.) If you do not like this new behaviour,
1326specify prefix, siteprefix, and vendorprefix explicitly.
1327
1328=item *
1329
1330A new optional location for Perl libraries, otherlibdirs, is available.
1331It can be used for example for vendor add-ons without disturbing Perl's
1332own library directories.
1333
1334=item *
1335
1336In many platforms the vendor-supplied 'cc' is too stripped-down to
1337build Perl (basically, 'cc' doesn't do ANSI C). If this seems
1338to be the case and 'cc' does not seem to be the GNU C compiler
1339'gcc', an automatic attempt is made to find and use 'gcc' instead.
1340
1341=item *
1342
1343gcc needs to closely track the operating system release to avoid
1344build problems. If Configure finds that gcc was built for a different
1345operating system release than is running, it now gives a clearly visible
1346warning that there may be trouble ahead.
1347
1348=item *
1349
1350If binary compatibility with the 5.005 release is not wanted, Configure
1351no longer suggests including the 5.005 modules in @INC.
1352
1353=item *
1354
1355Configure C<-S> can now run non-interactively.
1356
1357=item *
1358
44da0e71
JH
1359Configure support for pdp11-style memory models has been removed due
1360to obsolescence.
1361
1362=item *
1363
77c8cf41 1364configure.gnu now works with options with whitespace in them.
f39f21d8 1365
77c8cf41 1366=item *
f39f21d8 1367
77c8cf41 1368installperl now outputs everything to STDERR.
f39f21d8 1369
77c8cf41
JH
1370=item *
1371
1372$Config{byteorder} is now computed dynamically (this is more robust
1373with "fat binaries" where an executable image contains binaries for
1374more than one binary platform.)
f39f21d8
JH
1375
1376=item *
1377
1378Because PerlIO is now the default on most platforms, "-perlio" doesn't
1379get appended to the $Config{archname} (also known as $^O) anymore.
1380Instead, if you explicitly choose not to use perlio (Configure command
1381line option -Uuseperlio), you will get "-stdio" appended.
1382
1383=item *
1384
1385Another change related to the architecture name is that "-64all"
1386(-Duse64bitall, or "maximally 64-bit") is appended only if your
1387pointers are 64 bits wide. (To be exact, the use64bitall is ignored.)
1388
1389=item *
1390
77c8cf41
JH
1391In AFS installations one can configure the root of the AFS to be
1392somewhere else than the default F</afs> by using the Configure
1393parameter C<-Dafsroot=/some/where/else>.
1394
1395=item *
1396
61947107
JH
1397APPLLIB_EXP, a less-know configuration-time definition, has been
1398documented. It can be used to prepend site-specific directories
1399to Perl's default search path (@INC), see INSTALL for information.
1400
1401=item *
1402
77c8cf41
JH
1403The version of Berkeley DB used when the Perl (and, presumably, the
1404DB_File extension) was built is now available as
1405C<@Config{qw(db_version_major db_version_minor db_version_patch)}>
1406from Perl and as C<DB_VERSION_MAJOR_CFG DB_VERSION_MINOR_CFG
1407DB_VERSION_PATCH_CFG> from C.
1408
1409=item *
1410
61947107
JH
1411Building Berkeley DB3 for compatibility modes for DB, NDBM, and ODBM
1412has been documented in INSTALL.
77c8cf41
JH
1413
1414=item *
1415
61947107
JH
1416If you have CPAN access (either network or a local copy such as a
1417CD-ROM) you can during specify extra modules to Configure to build and
1418install with Perl using the -Dextras=... option. See INSTALL for
1419more details.
f39f21d8 1420
61947107 1421=item *
f39f21d8 1422
61947107
JH
1423In addition to config.over a new override file, config.arch, is
1424available. That is supposed to be used by hints file writers for
1425architecture-wide changes (as opposed to config.over which is for
1426site-wide changes).
f39f21d8
JH
1427
1428=item *
1429
e1f170bd
JH
1430If your file system supports symbolic links you can build Perl outside
1431of the source directory by
1432
1433 mkdir /tmp/perl/build/directory
1434 cd /tmp/perl/build/directory
1435 sh /path/to/perl/source/Configure -Dmksymlinks ...
1436
1437This will create in /tmp/perl/build/directory a tree of symbolic links
1438pointing to files in /path/to/perl/source. The original files are left
1439unaffected. After Configure has finished you can just say
1440
1441 make all test
1442
1443and Perl will be built and tested, all in /tmp/perl/build/directory.
1444
1445=item *
1446
61947107
JH
1447For Perl developers several new make targets for profiling
1448and debugging have been added, see L<perlhack>.
1449
1450=over 8
f39f21d8
JH
1451
1452=item *
1453
61947107
JH
1454Use of the F<gprof> tool to profile Perl has been documented in
1455L<perlhack>. There is a make target called "perl.gprof" for
1456generating a gprofiled Perl executable.
f39f21d8
JH
1457
1458=item *
1459
61947107
JH
1460If you have GCC 3, there is a make target called "perl.gcov" for
1461creating a gcoved Perl executable for coverage analysis. See
1462L<perlhack>.
f39f21d8
JH
1463
1464=item *
1465
61947107
JH
1466If you are on IRIX or Tru64 platforms, new profiling/debugging options
1467have been added, see L<perlhack> for more information about pixie and
1468Third Degree.
1469
1470=back
f39f21d8
JH
1471
1472=item *
1473
61947107
JH
1474Guidelines of how to construct minimal Perl installations have
1475been added to INSTALL.
f39f21d8
JH
1476
1477=item *
1478
61947107
JH
1479The Thread extension is now not built at all under ithreads
1480(C<Configure -Duseithreads>) because it wouldn't work anyway (the
1481Thread extension requires being Configured with C<-Duse5005threads>).
f39f21d8 1482
61947107
JH
1483But note that the Thread.pm interface is now shared by both
1484thread models.
f39f21d8 1485
61947107 1486=back
f39f21d8 1487
61947107 1488=head2 New Or Improved Platforms
f39f21d8 1489
61947107
JH
1490For the list of platforms known to support Perl,
1491see L<perlport/"Supported Platforms">.
1492
1493=over 4
f39f21d8
JH
1494
1495=item *
1496
61947107 1497AIX dynamic loading should be now better supported.
f39f21d8 1498
f39f21d8
JH
1499=item *
1500
77c8cf41
JH
1501AIX should now work better with gcc, threads, and 64-bitness. Also the
1502long doubles support in AIX should be better now. See L<perlaix>.
f39f21d8
JH
1503
1504=item *
1505
61947107
JH
1506After a long pause, AmigaOS has been verified to be happy with Perl.
1507
1508=item *
1509
77c8cf41 1510AtheOS (http://www.atheos.cx/) is a new platform.
f39f21d8 1511
77c8cf41 1512=item *
f39f21d8 1513
77c8cf41 1514DG/UX platform now supports the 5.005-style threads. See L<perldgux>.
f39f21d8
JH
1515
1516=item *
1517
77c8cf41 1518DYNIX/ptx platform (a.k.a. dynixptx) is supported at or near osvers 4.5.2.
f39f21d8
JH
1519
1520=item *
1521
61947107
JH
1522EBCDIC platforms (z/OS, also known as OS/390, POSIX-BC, and VM/ESA)
1523have been regained. Many test suite tests still fail and the
1524co-existence of Unicode and EBCDIC isn't quite settled, but the
1525situation is much better than with Perl 5.6. See L<perlos390>,
1526L<perlbs2000> (for POSIX-BC), and L<perlvmesa> for more information.
f39f21d8
JH
1527
1528=item *
1529
61947107
JH
1530Building perl with -Duseithreads or -Duse5005threads now works under
1531HP-UX 10.20 (previously it only worked under 10.30 or later). You will
1532need a thread library package installed. See README.hpux.
f39f21d8 1533
77c8cf41 1534=item *
f39f21d8 1535
61947107
JH
1536MacOS Classic (MacPerl has of course been available since
1537perl 5.004 but now the source code bases of standard Perl
1538and MacPerl have been synchronised)
f39f21d8 1539
77c8cf41 1540=item *
f39f21d8 1541
61947107
JH
1542MacOS X (or Darwin) should now be able to build Perl even on HFS+
1543filesystems. (The case-insensitivity confused the Perl build process.)
f39f21d8 1544
888aee59
JH
1545=item *
1546
61947107 1547NCR MP-RAS is now supported.
888aee59
JH
1548
1549=item *
1550
61947107 1551NetWare from Novell is now supported. See L<perlnetware>.
888aee59
JH
1552
1553=item *
1554
61947107 1555NonStop-UX is now supported.
888aee59
JH
1556
1557=item *
1558
44da0e71
JH
1559NEC SUPER-UX is now supported.
1560
1561=item *
1562
61947107 1563Amdahl UTS UNIX mainframe platform is now supported.
888aee59
JH
1564
1565=item *
1566
61947107
JH
1567WinCE is now supported. See L<perlce>.
1568
1569=item *
1570
1571z/OS (formerly known as OS/390, formerly known as MVS OE) has now
1572support for dynamic loading. This is not selected by default,
1573however, you must specify -Dusedl in the arguments of Configure.
888aee59 1574
f39f21d8
JH
1575=back
1576
1577=head1 Selected Bug Fixes
1578
e1f170bd
JH
1579Numerous memory leaks and uninitialized memory accesses have been
1580hunted down. Most importantly anonymous subs used to leak quite
1581a bit.
ba370e9b 1582
f39f21d8
JH
1583=over 4
1584
1585=item *
1586
e1f170bd 1587The autouse pragma didn't work for Multi::Part::Function::Names.
f39f21d8
JH
1588
1589=item *
1590
44da0e71
JH
1591caller() could cause core dumps in certain situations. Carp was sometimes
1592affected by this problem.
1593
1594=item *
1595
e1f170bd
JH
1596chop(@list) in list context returned the characters chopped in
1597reverse order. This has been reversed to be in the right order.
f39f21d8
JH
1598
1599=item *
1600
e1f170bd
JH
1601Configure no longer includes the DBM libraries (dbm, gdbm, db, ndbm)
1602when building the Perl binary. The only exception to this is SunOS 4.x,
1603which needs them.
f39f21d8
JH
1604
1605=item *
1606
e1f170bd
JH
1607The behaviour of non-decimal but numeric string constants such as
1608"0x23" was platform-dependent: in some platforms that was seen as 35,
1609in some as 0, in some as a floating point number (don't ask). This
1610was caused by Perl using the operating system libraries in a situation
1611where the result of the string to number conversion is undefined: now
1612Perl consistently handles such strings as zero in numeric contexts.
f39f21d8
JH
1613
1614=item *
1615
e1f170bd 1616The order of DESTROYs has been made more predictable.
f39f21d8
JH
1617
1618=item *
1619
e1f170bd
JH
1620Several debugger fixes: exit code now reflects the script exit code,
1621condition C<"0"> now treated correctly, the C<d> command now checks
44da0e71
JH
1622line number, the C<$.> no longer gets corrupted, all debugger output
1623now goes correctly to the socket if RemotePort is set.
1624
1625=item *
1626
1627Perl 5.6.0 could emit spurious warnings about redefinition of dl_error()
1628when statically building extensions into perl. This has been corrected.
f39f21d8
JH
1629
1630=item *
1631
e1f170bd 1632L<dprofpp> -R didn't work.
f39f21d8
JH
1633
1634=item *
1635
e1f170bd 1636C<*foo{FORMAT}> now works.
44da0e71
JH
1637=item *
1638
1639Infinity is now recognized as a number.
f39f21d8
JH
1640
1641=item *
1642
e1f170bd
JH
1643UNIVERSAL::isa no longer caches methods incorrectly. (This broke
1644the Tk extension with 5.6.0.)
f39f21d8
JH
1645
1646=item *
1647
e1f170bd
JH
1648Lexicals I: lexicals outside an eval "" weren't resolved
1649correctly inside a subroutine definition inside the eval "" if they
1650were not already referenced in the top level of the eval""ed code.
f39f21d8
JH
1651
1652=item *
1653
e1f170bd
JH
1654Lexicals II: lexicals leaked at file scope into subroutines that
1655were declared before the lexicals.
f39f21d8
JH
1656
1657=item *
1658
44da0e71
JH
1659Lexical warnings now propagating correctly between scopes
1660and into C<eval "...">.
1661
1662=item *
1663
1664C<use warnings qw(FATAL all)> did not work as intended. This has been
1665corrected.
1666
1667=item *
1668
1669warnings::enabled() now reports the state of $^W correctly if the caller
1670isn't using lexical warnings.
f39f21d8
JH
1671
1672=item *
1673
e1f170bd 1674Line renumbering with eval and C<#line> now works.
f39f21d8
JH
1675
1676=item *
1677
e1f170bd 1678Fixed numerous memory leaks, especially in eval "".
f39f21d8
JH
1679
1680=item *
1681
e1f170bd
JH
1682mkdir() now ignores trailing slashes in the directory name,
1683as mandated by POSIX.
f39f21d8
JH
1684
1685=item *
1686
e1f170bd
JH
1687Some versions of glibc have a broken modfl(). This affects builds
1688with C<-Duselongdouble>. This version of Perl detects this brokenness
1689and has a workaround for it. The glibc release 2.2.2 is known to have
1690fixed the modfl() bug.
f39f21d8
JH
1691
1692=item *
1693
e1f170bd
JH
1694Modulus of unsigned numbers now works (4063328477 % 65535 used to
1695return 27406, instead of 27047).
f39f21d8
JH
1696
1697=item *
1698
e1f170bd
JH
1699Some "not a number" warnings introduced in 5.6.0 eliminated to be
1700more compatible with 5.005. Infinity is now recognised as a number.
f39f21d8 1701
77c8cf41 1702=item *
f39f21d8 1703
44da0e71
JH
1704Numeric conversions did not recognize changes in the string value
1705properly in certain circumstances.
1706
1707=item *
1708
e1f170bd 1709Attributes (like :shared) didn't work with our().
f39f21d8
JH
1710
1711=item *
1712
e1f170bd 1713our() variables will not cause "will not stay shared" warnings.
f39f21d8
JH
1714
1715=item *
1716
44da0e71
JH
1717"our" variables of the same name declared in two sibling blocks
1718resulted in bogus warnings about "redeclaration" of the variables.
1719The problem has been corrected.
1720
1721=item *
1722
e1f170bd 1723pack "Z" now correctly terminates the string with "\0".
f39f21d8
JH
1724
1725=item *
1726
e1f170bd
JH
1727Fix password routines which in some shadow password platforms
1728(e.g. HP-UX) caused getpwent() to return every other entry.
f39f21d8 1729
77c8cf41 1730=item *
f39f21d8 1731
e1f170bd
JH
1732The PERL5OPT environment variable (for passing command line arguments
1733to Perl) didn't work for more than a single group of options.
f39f21d8 1734
77c8cf41 1735=item *
f39f21d8 1736
e1f170bd 1737PERL5OPT with embedded spaces didn't work.
f39f21d8 1738
77c8cf41 1739=item *
f39f21d8 1740
e1f170bd 1741printf() no longer resets the numeric locale to "C".
f39f21d8 1742
77c8cf41 1743=item *
f39f21d8 1744
44da0e71
JH
1745C<qw(a\\b)> now parses correctly as C<'a\\b'>.
1746
1747=item *
1748
1749pos() did not return the correct value within s///ge in earlier
1750versions. This is now handled correctly.
f39f21d8 1751
77c8cf41 1752=item *
f39f21d8 1753
e1f170bd
JH
1754Printing quads (64-bit integers) with printf/sprintf now works
1755without the q L ll prefixes (assuming you are on a quad-capable platform).
f39f21d8 1756
77c8cf41 1757=item *
f39f21d8 1758
e1f170bd 1759Regular expressions on references and overloaded scalars now work.
f39f21d8 1760
ba370e9b
JH
1761=item *
1762
e1f170bd
JH
1763Right-hand side magic (GMAGIC) could in many cases such as string
1764concatenation be invoked too many times.
ba370e9b
JH
1765
1766=item *
1767
e1f170bd 1768scalar() now forces scalar context even when used in void context.
ba370e9b
JH
1769
1770=item *
1771
e1f170bd 1772SOCKS support is now much more robust.
ba370e9b
JH
1773
1774=item *
1775
e1f170bd
JH
1776sort() arguments are now compiled in the right wantarray context
1777(they were accidentally using the context of the sort() itself).
44da0e71
JH
1778The comparison block is now run in scalar context, and the arguments
1779to be sorted are always provided list context.
ba370e9b
JH
1780
1781=item *
1782
e1f170bd 1783Changed the POSIX character class C<[[:space:]]> to include the (very
c2e23569
JH
1784rarely used) vertical tab character. Added a new POSIX-ish character
1785class C<[[:blank:]]> which stands for horizontal whitespace
1786(currently, the space and the tab).
ba370e9b
JH
1787
1788=item *
1789
1790The tainting behaviour of sprintf() has been rationalized. It does
1791not taint the result of floating point formats anymore, making the
1792behaviour consistent with that of string interpolation.
1793
1794=item *
1795
44da0e71
JH
1796Some cases of inconsistent taint propagation (such as within hash
1797values) have been fixed.
1798
1799=item *
1800
1801The RE engine found in Perl 5.6.0 accidentally pessimised certain kinds
1802of simple pattern matches. These are now handled better.
1803
1804=item *
1805
1806Regular expression debug output (whether through C<use re 'debug'>
1807or via C<-Dr>) now looks better.
1808
1809=item *
1810
1811Multi-line matches like C<"a\nxb\n" =~ /(?!\A)x/m> were flawed. The
1812bug has been fixed.
1813
1814=item *
1815
1816Use of $& could trigger a core dump under some situations. This
1817is now avoided.
1818
1819=item *
1820
c2e23569
JH
1821The regular expression captured submatches ($1, $2, ...) are now
1822more consistently unset if the match fails, instead of leaving false
1823data lying around in them.
1824
1825=item *
1826
44da0e71
JH
1827readline() on files opened in "slurp" mode could return an extra "" at
1828the end in certain situations. This has been corrected.
1829
1830=item *
1831
1832Autovivification of symbolic references of special variables described
1833in L<perlvar> (as in C<${$num}>) was accidentally disabled. This works
1834again now.
1835
1836=item *
1837
da6838c8 1838Sys::Syslog ignored the C<LOG_AUTH> constant.
ba370e9b
JH
1839
1840=item *
1841
e1f170bd 1842All but the first argument of the IO syswrite() method are now optional.
ba370e9b
JH
1843
1844=item *
1845
e1f170bd
JH
1846$AUTOLOAD, sort(), lock(), and spawning subprocesses
1847in multiple threads simultaneously are now thread-safe.
ba370e9b
JH
1848
1849=item *
1850
e1f170bd 1851Tie::ARRAY SPLICE method was broken.
ba370e9b
JH
1852
1853=item *
1854
e1f170bd 1855Allow read-only string on left hand side of non-modifying tr///.
ba370e9b
JH
1856
1857=item *
1858
e1f170bd 1859Several Unicode fixes.
ba370e9b
JH
1860
1861=over 8
1862
1863=item *
1864
e1f170bd
JH
1865BOMs (byte order marks) in the beginning of Perl files
1866(scripts, modules) should now be transparently skipped.
1867UTF-16 (UCS-2) encoded Perl files should now be read correctly.
ba370e9b
JH
1868
1869=item *
1870
e1f170bd 1871The character tables have been updated to Unicode 3.1.1.
ba370e9b
JH
1872
1873=item *
1874
e1f170bd
JH
1875Comparing with utf8 data does not magically upgrade non-utf8 data
1876into utf8.
ba370e9b
JH
1877
1878=item *
1879
e1f170bd 1880C<IsAlnum>, C<IsAlpha>, and C<IsWord> now match titlecase.
f39f21d8 1881
77c8cf41 1882=item *
f39f21d8 1883
e1f170bd
JH
1884Concatenation with the C<.> operator or via variable interpolation,
1885C<eq>, C<substr>, C<reverse>, C<quotemeta>, the C<x> operator,
1886substitution with C<s///>, single-quoted UTF8, should now work.
f39f21d8 1887
77c8cf41 1888=item *
f39f21d8 1889
e1f170bd
JH
1890The C<tr///> operator now works. Note that the C<tr///CU>
1891functionality has been removed (but see pack('U0', ...)).
f39f21d8 1892
77c8cf41 1893=item *
f39f21d8 1894
e1f170bd 1895C<eval "v200"> now works.
f39f21d8 1896
77c8cf41 1897=item *
f39f21d8 1898
44da0e71
JH
1899Perl 5.6.0 parsed m/\x{ab}/ incorrectly, leading to spurious warnings.
1900This has been corrected.
1901
1902=item *
1903
e1f170bd 1904Zero entries were missing from the Unicode classes like C<IsDigit>.
f39f21d8 1905
e1f170bd 1906=back
f39f21d8 1907
44da0e71
JH
1908=item *
1909
1910Large unsigned numbers (those above 2**31) could sometimes lose their
1911unsignedness, causing bogus results in arithmetic operations.
1912
77c8cf41 1913=back
f39f21d8 1914
77c8cf41 1915=head2 Platform Specific Changes and Fixes
f39f21d8
JH
1916
1917=over 4
1918
1919=item *
1920
77c8cf41 1921BSDI 4.*
f39f21d8 1922
77c8cf41 1923Perl now works on post-4.0 BSD/OSes.
f39f21d8
JH
1924
1925=item *
1926
77c8cf41 1927All BSDs
f39f21d8 1928
057b7f2b 1929Setting C<$0> now works (as much as possible; see L<perlvar> for details).
f39f21d8
JH
1930
1931=item *
1932
77c8cf41 1933Cygwin
f39f21d8 1934
77c8cf41 1935Numerous updates; currently synchronised with Cygwin 1.1.4.
f39f21d8
JH
1936
1937=item *
1938
e1f170bd
JH
1939Previously DYNIX/ptx had problems in its Configure probe for non-blocking I/O.
1940
1941=item *
1942
77c8cf41 1943EPOC
f39f21d8 1944
77c8cf41 1945EPOC update after Perl 5.6.0. See README.epoc.
f39f21d8
JH
1946
1947=item *
1948
77c8cf41 1949FreeBSD 3.*
f39f21d8 1950
77c8cf41 1951Perl now works on post-3.0 FreeBSDs.
f39f21d8
JH
1952
1953=item *
1954
77c8cf41
JH
1955HP-UX
1956
1957README.hpux updated; C<Configure -Duse64bitall> now almost works.
f39f21d8
JH
1958
1959=item *
1960
77c8cf41 1961IRIX
f39f21d8 1962
77c8cf41
JH
1963Numerous compilation flag and hint enhancements; accidental mixing
1964of 32-bit and 64-bit libraries (a doomed attempt) made much harder.
f39f21d8 1965
77c8cf41 1966=item *
f39f21d8 1967
77c8cf41 1968Linux
f39f21d8 1969
e1f170bd
JH
1970=over 8
1971
1972=item *
1973
77c8cf41 1974Long doubles should now work (see INSTALL).
f39f21d8
JH
1975
1976=item *
1977
e1f170bd
JH
1978Linux previously had problems related to sockaddrlen when using
1979accept(), revcfrom() (in Perl: recv()), getpeername(), and getsockname().
1980
1981=back
1982
1983=item *
1984
77c8cf41 1985MacOS Classic
f39f21d8 1986
77c8cf41
JH
1987Compilation of the standard Perl distribution in MacOS Classic should
1988now work if you have the Metrowerks development environment and
1989the missing Mac-specific toolkit bits. Contact the macperl mailing
1990list for details.
f39f21d8
JH
1991
1992=item *
1993
77c8cf41 1994MPE/iX
f39f21d8 1995
77c8cf41 1996MPE/iX update after Perl 5.6.0. See README.mpeix.
f39f21d8
JH
1997
1998=item *
1999
77c8cf41 2000NetBSD/sparc
f39f21d8 2001
77c8cf41 2002Perl now works on NetBSD/sparc.
f39f21d8
JH
2003
2004=item *
2005
77c8cf41 2006OS/2
f39f21d8 2007
77c8cf41 2008Now works with usethreads (see INSTALL).
f39f21d8
JH
2009
2010=item *
2011
77c8cf41 2012Solaris
f39f21d8 2013
77c8cf41 201464-bitness using the Sun Workshop compiler now works.
f39f21d8
JH
2015
2016=item *
2017
77c8cf41 2018Tru64 (aka Digital UNIX, aka DEC OSF/1)
f39f21d8 2019
77c8cf41
JH
2020The operating system version letter now recorded in $Config{osvers}.
2021Allow compiling with gcc (previously explicitly forbidden). Compiling
2022with gcc still not recommended because buggy code results, even with
2023gcc 2.95.2.
f39f21d8
JH
2024
2025=item *
2026
77c8cf41
JH
2027Unicos
2028
2029Fixed various alignment problems that lead into core dumps either
2030during build or later; no longer dies on math errors at runtime;
2031now using full quad integers (64 bits), previously was using
2032only 46 bit integers for speed.
f39f21d8
JH
2033
2034=item *
2035
77c8cf41
JH
2036VMS
2037
2038chdir() now works better despite a CRT bug; now works with MULTIPLICITY
2039(see INSTALL); now works with Perl's malloc.
f39f21d8 2040
00bb525a
CB
2041The tainting of C<%ENV> elements via C<keys> or C<values> was previously
2042unimplemented. It now works as documented.
2043
2044The C<waitpid> emulation has been improved. The worst bug (now fixed)
2045was that a pid of -1 would cause a wildcard search of all processes on
2046the system. The most significant enhancement is that we can now
2047usually get the completion status of a terminated process.
2048
2049POSIX-style signals are now emulated much better on VMS versions prior
2050to 7.0.
2051
2052The C<system> function and backticks operator have improved
2053functionality and better error handling.
2054
f39f21d8
JH
2055=item *
2056
77c8cf41 2057Windows
f39f21d8 2058
77c8cf41 2059=over 8
f39f21d8
JH
2060
2061=item *
2062
77c8cf41 2063accept() no longer leaks memory.
f39f21d8
JH
2064
2065=item *
2066
e1f170bd
JH
2067Borland C++ v5.5 is now a supported compiler that can build Perl.
2068However, the generated binaries continue to be incompatible with those
2069generated by the other supported compilers (GCC and Visual C++).
2070
2071=item *
2072
77c8cf41 2073Better chdir() return value for a non-existent directory.
f39f21d8 2074
77c8cf41 2075=item *
f39f21d8 2076
e1f170bd
JH
2077Duping socket handles with open(F, ">&MYSOCK") now works under Windows 9x.
2078
2079=item *
2080
77c8cf41 2081New %ENV entries now propagate to subprocesses.
f39f21d8
JH
2082
2083=item *
2084
44da0e71
JH
2085Current directory entries in %ENV are now correctly propagated to child
2086processes.
2087
2088=item *
2089
77c8cf41
JH
2090$ENV{LIB} now used to search for libs under Visual C.
2091
2092=item *
2093
44da0e71
JH
2094fork() emulation has been improved in various ways, but still continues
2095to be experimental. See L<perlfork> for known bugs and caveats.
e1f170bd
JH
2096
2097=item *
2098
77c8cf41 2099A failed (pseudo)fork now returns undef and sets errno to EAGAIN.
f39f21d8
JH
2100
2101=item *
2102
44da0e71
JH
2103Win32::GetCwd() correctly returns C:\ instead of C: when at the drive root.
2104Other bugs in chdir() and Cwd::cwd() have also been fixed.
2105
2106=item *
2107
e1f170bd
JH
2108HTML files will be installed in c:\perl\html instead of c:\perl\lib\pod\html
2109
2110=item *
2111
2112The makefiles now provide a single switch to bulk-enable all the features
2113enabled in ActiveState ActivePerl (a popular Win32 binary distribution).
2114
2115=item *
2116
77c8cf41 2117Allow REG_EXPAND_SZ keys in the registry.
f39f21d8
JH
2118
2119=item *
2120
77c8cf41 2121Can now send() from all threads, not just the first one.
f39f21d8
JH
2122
2123=item *
2124
77c8cf41 2125Fake signal handling reenabled, bugs and all.
f39f21d8
JH
2126
2127=item *
2128
44da0e71
JH
2129%SIG has been enabled under USE_ITHREADS, but its use is completely
2130unsupported under all configurations.
2131
2132=item *
2133
77c8cf41
JH
2134Less stack reserved per thread so that more threads can run
2135concurrently. (Still 16M per thread.)
f39f21d8
JH
2136
2137=item *
2138
c2e23569 2139C<File::Spec-&gt;tmpdir()> now prefers C:/temp over /tmp
77c8cf41 2140(works better when perl is running as service).
f39f21d8
JH
2141
2142=item *
2143
77c8cf41 2144Better UNC path handling under ithreads.
f39f21d8
JH
2145
2146=item *
2147
44da0e71
JH
2148wait(), waitpid() and backticks now return the correct exit status under
2149Windows 9x.
f39f21d8
JH
2150
2151=item *
2152
77c8cf41 2153winsock handle leak fixed.
f39f21d8
JH
2154
2155=back
2156
77c8cf41 2157=back
f39f21d8 2158
77c8cf41 2159=head1 New or Changed Diagnostics
f39f21d8 2160
ba370e9b
JH
2161=over 4
2162
2163=item *
2164
77c8cf41
JH
2165All regular expression compilation error messages are now hopefully
2166easier to understand both because the error message now comes before
2167the failed regex and because the point of failure is now clearly
ba370e9b
JH
2168marked by a C<E<lt>-- HERE> marker.
2169
2170=item *
f39f21d8 2171
77c8cf41
JH
2172The various "opened only for", "on closed", "never opened" warnings
2173drop the C<main::> prefix for filehandles in the C<main> package,
bea4d472 2174for example C<STDIN> instead of C<main::STDIN>.
f39f21d8 2175
ba370e9b
JH
2176=item *
2177
77c8cf41
JH
2178The "Unrecognized escape" warning has been extended to include C<\8>,
2179C<\9>, and C<\_>. There is no need to escape any of the C<\w> characters.
f39f21d8 2180
ba370e9b 2181=item *
f39f21d8 2182
77c8cf41
JH
2183Two new debugging options have been added: if you have compiled your
2184Perl with debugging, you can use the -DT and -DR options to trace
2185tokenising and to add reference counts to displaying variables,
2186respectively.
f39f21d8
JH
2187
2188=item *
2189
77c8cf41
JH
2190If an attempt to use a (non-blessed) reference as an array index
2191is made, a warning is given.
f39f21d8
JH
2192
2193=item *
2194
77c8cf41
JH
2195C<push @a;> and C<unshift @a;> (with no values to push or unshift)
2196now give a warning. This may be a problem for generated and evaled
2197code.
f39f21d8 2198
ba370e9b
JH
2199=item *
2200
2201If you try to L<perlfunc/pack> a number less than 0 or larger than 255
2202using the C<"C"> format you will get an optional warning. Similarly
2203for the C<"c"> format and a number less than -128 or more than 127.
2204
2205=item *
2206
2207Certain regex modifiers such as C<(?o)> make sense only if applied to
2208the entire regex. You will an optional warning if you try to do otherwise.
2209
2210=item *
2211
c2e23569
JH
2212Using arrays or hashes as references (e.g. C<< %foo-&gt;{bar} >>
2213has been deprecated for a while. Now you will get an optional warning.
ba370e9b 2214
f39f21d8
JH
2215=back
2216
77c8cf41 2217=head1 Changed Internals
f39f21d8
JH
2218
2219=over 4
2220
2221=item *
2222
77c8cf41
JH
2223perlapi.pod (a companion to perlguts) now attempts to document the
2224internal API.
f39f21d8
JH
2225
2226=item *
2227
77c8cf41
JH
2228You can now build a really minimal perl called microperl.
2229Building microperl does not require even running Configure;
2230C<make -f Makefile.micro> should be enough. Beware: microperl makes
2231many assumptions, some of which may be too bold; the resulting
2232executable may crash or otherwise misbehave in wondrous ways.
2233For careful hackers only.
f39f21d8
JH
2234
2235=item *
2236
c2e23569
JH
2237Added rsignal(), whichsig(), do_join(), op_clear, op_null,
2238ptr_table_clear(), ptr_table_free(), sv_setref_uv(), and several UTF-8
2239interfaces to the publicised API. For the full list of the available
2240APIs see L<perlapi>.
f39f21d8
JH
2241
2242=item *
2243
77c8cf41 2244Made possible to propagate customised exceptions via croak()ing.
f39f21d8 2245
77c8cf41 2246=item *
f39f21d8 2247
95f0a2f1
SB
2248Now xsubs can have attributes just like subs. (Well, at least the
2249built-in attributes.)
f39f21d8
JH
2250
2251=item *
2252
77c8cf41
JH
2253dTHR and djSP have been obsoleted; the former removed (because it's
2254a no-op) and the latter replaced with dSP.
f39f21d8
JH
2255
2256=item *
2257
61947107
JH
2258PERL_OBJECT has been completely removed.
2259
2260=item *
2261
ba370e9b
JH
2262The MAGIC constants (e.g. C<'P'>) have been macrofied
2263(e.g. C<PERL_MAGIC_TIED>) for better source code readability
2264and maintainability.
2265
2266=item *
2267
2268The regex compiler now maintains a structure that identifies nodes in
2269the compiled bytecode with the corresponding syntactic features of the
2270original regex expression. The information is attached to the new
2271C<offsets> member of the C<struct regexp>. See L<perldebguts> for more
2272complete information.
2273
2274=item *
2275
2276The C code has been made much more C<gcc -Wall> clean. Some warning
2277messages still remain in some platforms, so if you are compiling with
2278gcc you may see some warnings about dubious practices. The warnings
2279are being worked on.
2280
2281=item *
2282
2283F<perly.c>, F<sv.c>, and F<sv.h> have now been extensively commented.
2284
2285=item *
2286
61947107
JH
2287Documentation on how to use the Perl source repository has been added
2288to F<Porting/repository.pod>.
f39f21d8 2289
888aee59
JH
2290=item *
2291
c2e23569 2292There are now several profiling make targets.
888aee59 2293
77c8cf41 2294=back
f39f21d8 2295
77c8cf41 2296=head1 Security Vulnerability Closed
f39f21d8 2297
77c8cf41 2298(This change was already made in 5.7.0 but bears repeating here.)
f39f21d8 2299
77c8cf41
JH
2300A potential security vulnerability in the optional suidperl component
2301of Perl was identified in August 2000. suidperl is neither built nor
2302installed by default. As of November 2001 the only known vulnerable
2303platform is Linux, most likely all Linux distributions. CERT and
2304various vendors and distributors have been alerted about the vulnerability.
2305See http://www.cpan.org/src/5.0/sperl-2000-08-05/sperl-2000-08-05.txt
2306for more information.
f39f21d8 2307
77c8cf41
JH
2308The problem was caused by Perl trying to report a suspected security
2309exploit attempt using an external program, /bin/mail. On Linux
2310platforms the /bin/mail program had an undocumented feature which
2311when combined with suidperl gave access to a root shell, resulting in
2312a serious compromise instead of reporting the exploit attempt. If you
2313don't have /bin/mail, or if you have 'safe setuid scripts', or if
2314suidperl is not installed, you are safe.
f39f21d8 2315
77c8cf41
JH
2316The exploit attempt reporting feature has been completely removed from
2317Perl 5.8.0 (and the maintenance release 5.6.1, and it was removed also
2318from all the Perl 5.7 releases), so that particular vulnerability
2319isn't there anymore. However, further security vulnerabilities are,
ba370e9b
JH
2320unfortunately, always possible. The suidperl functionality is most
2321probably going to be removed in Perl 5.10. In any case, suidperl
2322should only be used by security experts who know exactly what they are
2323doing and why they are using suidperl instead of some other solution
2324such as sudo (see http://www.courtesan.com/sudo/).
77c8cf41
JH
2325
2326=head1 New Tests
2327
76663d67
JH
2328Several new tests have been added, especially for the F<lib>
2329subsection. There are now about 34 000 individual tests (spread over
2330about 530 test scripts), in the regression suite (5.6.1 has about
233111700 tests, in 258 test scripts) Many of the new tests are introduced
2332by the new modules, but still in general Perl is now more thoroughly
2333tested.
2334
2335Because of the large number of tests, running the regression suite
2336will take considerably longer time than it used to: expect the suite
2337to take up to 4-5 times longer to run than in perl 5.6. In a really
2338fast machine you can hope to finish the suite in about 5 minutes
2339(wallclock time).
77c8cf41
JH
2340
2341The tests are now reported in a different order than in earlier Perls.
2342(This happens because the test scripts from under t/lib have been moved
2343to be closer to the library/extension they are testing.)
2344
f39f21d8
JH
2345=head1 Known Problems
2346
f39f21d8
JH
2347=head2 AIX
2348
2349=over 4
2350
2351=item *
2352
2353In AIX 4.2 Perl extensions that use C++ functions that use statics
2354may have problems in that the statics are not getting initialized.
2355In newer AIX releases this has been solved by linking Perl with
2356the libC_r library, but unfortunately in AIX 4.2 the said library
2357has an obscure bug where the various functions related to time
2358(such as time() and gettimeofday()) return broken values, and
2359therefore in AIX 4.2 Perl is not linked against the libC_r.
2360
2361=item *
2362
2363vac 5.0.0.0 May Produce Buggy Code For Perl
2364
2365The AIX C compiler vac version 5.0.0.0 may produce buggy code,
2366resulting in few random tests failing, but when the failing tests
2367are run by hand, they succeed. We suggest upgrading to at least
2368vac version 5.0.1.0, that has been known to compile Perl correctly.
2369"lslpp -L|grep vac.C" will tell you the vac version.
2370
2371=back
2372
2373=head2 Amiga Perl Invoking Mystery
2374
2375One cannot call Perl using the C<volume:> syntax, that is, C<perl -v>
057b7f2b 2376works, but for example C<bin:perl -v> doesn't. The exact reason isn't
f39f21d8
JH
2377known but the current suspect is the F<ixemul> library.
2378
2379=head2 lib/ftmp-security tests warn 'system possibly insecure'
2380
2381Don't panic. Read INSTALL 'make test' section instead.
2382
2383=head2 Cygwin intermittent failures of lib/Memoize/t/expire_file 11 and 12
2384
2385The subtests 11 and 12 sometimes fail and sometimes work.
2386
2387=head2 HP-UX lib/io_multihomed Fails When LP64-Configured
2388
2389The lib/io_multihomed test may hang in HP-UX if Perl has been
2390configured to be 64-bit. Because other 64-bit platforms do not hang in
2391this test, HP-UX is suspect. All other tests pass in 64-bit HP-UX. The
2392test attempts to create and connect to "multihomed" sockets (sockets
2393which have multiple IP addresses).
2394
2395=head2 HP-UX lib/posix Subtest 9 Fails When LP64-Configured
2396
2397If perl is configured with -Duse64bitall, the successful result of the
2398subtest 10 of lib/posix may arrive before the successful result of the
2399subtest 9, which confuses the test harness so much that it thinks the
2400subtest 9 failed.
2401
2402=head2 Linux With Sfio Fails op/misc Test 48
2403
2404No known fix.
2405
a0aae13b
JH
2406=head2 Mac OS X
2407
2408The following tests are known to fail:
2409
2410 Failed Test Stat Wstat Total Fail Failed List of Failed
2411 -------------------------------------------------------------------------
2412 ../ext/DB_File/t/db-btree.t 0 11 ?? ?? % ??
2413 ../ext/DB_File/t/db-recno.t 149 3 2.01% 61 63 65
2414 ../ext/POSIX/t/posix.t 31 1 3.23% 10
2415 ../lib/warnings.t 450 1 0.22% 316
2416
f39f21d8
JH
2417=head2 OS/390
2418
2419OS/390 has rather many test failures but the situation is actually
2420better than it was in 5.6.0, it's just that so many new modules and
2421tests have been added.
2422
2423 Failed Test Stat Wstat Total Fail Failed List of Failed
2424 -----------------------------------------------------------------------------
2425 ../ext/B/Deparse.t 14 1 7.14% 14
2426 ../ext/B/Showlex.t 1 1 100.00% 1
2427 ../ext/Encode/Encode/Tcl.t 610 13 2.13% 592 594 596 598
2428 600 602 604-610
2429 ../ext/IO/lib/IO/t/io_unix.t 113 28928 5 3 60.00% 3-5
2430 ../ext/POSIX/POSIX.t 29 1 3.45% 14
2431 ../ext/Storable/t/lock.t 255 65280 5 3 60.00% 3-5
2432 ../lib/locale.t 129 33024 117 19 16.24% 99-117
2433 ../lib/warnings.t 434 1 0.23% 75
2434 ../lib/ExtUtils.t 27 1 3.70% 25
2435 ../lib/Math/BigInt/t/bigintpm.t 1190 1 0.08% 1145
2436 ../lib/Unicode/UCD.t 81 48 59.26% 1-16 49-64 66-81
2437 ../lib/User/pwent.t 9 1 11.11% 4
2438 op/pat.t 660 6 0.91% 242-243 424-425
2439 626-627
2440 op/split.t 0 9 ?? ?? % ??
2441 op/taint.t 174 3 1.72% 156 162 168
2442 op/tr.t 70 3 4.29% 50 58-59
2443 Failed 16/422 test scripts, 96.21% okay. 105/23251 subtests failed, 99.55% okay.
2444
2445=head2 op/sprintf tests 129 and 130
2446
2447The op/sprintf tests 129 and 130 are known to fail on some platforms.
2448Examples include any platform using sfio, and Compaq/Tandem's NonStop-UX.
2449The failing platforms do not comply with the ANSI C Standard, line
245019ff on page 134 of ANSI X3.159 1989 to be exact. (They produce
2451something other than "1" and "-1" when formatting 0.6 and -0.6 using
2452the printf format "%.0f", most often they produce "0" and "-0".)
2453
2454=head2 Failure of Thread tests
2455
fedd8cf1
JH
2456B<Note that support for 5.005-style threading remains experimental
2457and practically unsupported.>
f39f21d8
JH
2458
2459The following tests are known to fail due to fundamental problems in
2460the 5.005 threading implementation. These are not new failures--Perl
24615.005_0x has the same bugs, but didn't have these tests.
2462
fedd8cf1
JH
2463 ext/List/Util/t/first 2
2464 lib/autouse 4
2465 ext/Thread/thr5005 19-20
2466
2467These failures are unlikely to get fixed.
f39f21d8
JH
2468
2469=head2 UNICOS
2470
2471=over 4
2472
2473=item *
2474
2475ext/POSIX/sigaction subtests 6 and 13 may fail.
2476
2477=item *
2478
2479lib/ExtUtils may spuriously claim that subtest 28 failed,
2480which is interesting since the test only has 27 tests.
2481
2482=item *
2483
2484Numerous numerical test failures
2485
2486 op/numconvert 209,210,217,218
2487 op/override 7
2488 ext/Time/HiRes/HiRes 9
2489 lib/Math/BigInt/t/bigintpm 1145
2490 lib/Math/Trig 25
2491
2492These tests fail because of yet unresolved floating point inaccuracies.
2493
2494=back
2495
2496=head2 UTS
2497
2498There are a few known test failures, see L<perluts>.
2499
2500=head2 VMS
2501
00bb525a 2502There is one known test failure with a default configuration:
7207e29d 2503
aecce728 2504 [.run]switches..........................FAILED on test 1
7207e29d 2505
f39f21d8
JH
2506=head2 Win32
2507
2508In multi-CPU boxes there are some problems with the I/O buffering:
2509some output may appear twice.
2510
2511=head2 Localising a Tied Variable Leaks Memory
2512
2513 use Tie::Hash;
2514 tie my %tie_hash => 'Tie::StdHash';
2515
2516 ...
2517
2518 local($tie_hash{Foo}) = 1; # leaks
2519
2520Code like the above is known to leak memory every time the local()
2521is executed.
2522
aecce728
JH
2523=head2 Localising Tied Arrays and Hashes Is Broken
2524
2525 local %tied_array;
2526
2527doesn't work as one would expect: the old value is restored
2528incorrectly.
2529
f39f21d8
JH
2530=head2 Self-tying of Arrays and Hashes Is Forbidden
2531
2532Self-tying of arrays and hashes is broken in rather deep and
2533hard-to-fix ways. As a stop-gap measure to avoid people from getting
2534frustrated at the mysterious results (core dumps, most often) it is
2535for now forbidden (you will get a fatal error even from an attempt).
2536
f39f21d8
JH
2537=head2 Building Extensions Can Fail Because Of Largefiles
2538
2539Some extensions like mod_perl are known to have issues with
2540`largefiles', a change brought by Perl 5.6.0 in which file offsets
2541default to 64 bits wide, where supported. Modules may fail to compile
2542at all or compile and work incorrectly. Currently there is no good
2543solution for the problem, but Configure now provides appropriate
2544non-largefile ccflags, ldflags, libswanted, and libs in the %Config
2545hash (e.g., $Config{ccflags_nolargefiles}) so the extensions that are
2546having problems can try configuring themselves without the
2547largefileness. This is admittedly not a clean solution, and the
2548solution may not even work at all. One potential failure is whether
2549one can (or, if one can, whether it's a good idea) link together at
2550all binaries with different ideas about file offsets, all this is
2551platform-dependent.
2552
aecce728
JH
2553=head2 Unicode Support on EBCDIC Still Spotty
2554
2555Though mostly working, Unicode support still has problem spots on
2556EBCDIC platforms. One such known spot are the C<\p{}> and C<\P{}>
2557regular expression constructs for code points less than 256: the
2558pP are testing for Unicode code points, not knowing about EBCDIC.
2559
f39f21d8
JH
2560=head2 The Compiler Suite Is Still Experimental
2561
44da0e71
JH
2562The compiler suite is slowly getting better but it continues to be
2563highly experimental. Use in production environments is discouraged.
f39f21d8 2564
c4f1ce08 2565=head2 The Long Double Support Is Still Experimental
f39f21d8
JH
2566
2567The ability to configure Perl's numbers to use "long doubles",
2568floating point numbers of hopefully better accuracy, is still
2569experimental. The implementations of long doubles are not yet
2570widespread and the existing implementations are not quite mature
2571or standardised, therefore trying to support them is a rare
2572and moving target. The gain of more precision may also be offset
2573by slowdown in computations (more bits to move around, and the
2574operations are more likely to be executed by less optimised
2575libraries).
33a87e58 2576
c4f1ce08
JH
2577=head2 Seen In Perl 5.7 But Gone Now
2578
2579Some modules were seen in the Perl 5.7 development releases
2580but are not present in 5.8.0.
2581
2582=over 4
2583
2584=item *
2585
2586C<Attribute::Handlers> was removed because the implementation of C<my>
2587variable attributes changed so much that the Attribute::Handlers will
2588require a major rewrite. (This means that you can't use
2589Attribute::Handler 0.76 with Perl 5.8.0.)
2590
2591=item *
2592
2593C<Time::Piece> (previously known as C<Time::Object>) was removed
2594because it was felt that it didn't have enough value in it to be a
2595core module. It is still a useful module, though, and is available
2596from the CPAN.
2597
2598=back
2599
cc0fca54
GS
2600=head1 Reporting Bugs
2601
d4ad863d
JH
2602If you find what you think is a bug, you might check the articles
2603recently posted to the comp.lang.perl.misc newsgroup and the perl
2604bug database at http://bugs.perl.org. There may also be
06a5f41f 2605information at http://www.perl.com/, the Perl Home Page.
cc0fca54
GS
2606
2607If you believe you have an unreported bug, please run the B<perlbug>
2608program included with your release. Be sure to trim your bug down
2609to a tiny but sufficient test case. Your bug report, along with the
d4ad863d 2610output of C<perl -V>, will be sent off to perlbug@perl.org to be
cc0fca54
GS
2611analysed by the Perl porting team.
2612
2613=head1 SEE ALSO
2614
2615The F<Changes> file for exhaustive details on what changed.
2616
2617The F<INSTALL> file for how to build Perl.
2618
2619The F<README> file for general stuff.
2620
2621The F<Artistic> and F<Copying> files for copyright information.
2622
2623=head1 HISTORY
2624
d468ca04 2625Written by Jarkko Hietaniemi <F<jhi@iki.fi>>.
cc0fca54
GS
2626
2627=cut