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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 and the
85.8.0 release.
9
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10=head1 Incompatible Changes
11
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12=head2 64-bit platforms and malloc
13
057b7f2b 14If your pointers are 64 bits wide, the Perl malloc is no longer being
c2e23569 15used because it does not work well with 8-byte pointers. Also,
61947107 16usually the system mallocs on such platforms are much better optimized
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17for such large memory models than the Perl malloc. Some memory-hungry
18Perl applications like the PDL don't work well with Perl's malloc.
19Finally, other applications than Perl (like modperl) tend to prefer
20the system malloc. Such platforms include Alpha and 64-bit HPPA,
21MIPS, PPC, and Sparc.
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22
23=head2 AIX Dynaloading
24
25The AIX dynaloading now uses in AIX releases 4.3 and newer the native
26dlopen interface of AIX instead of the old emulated interface. This
27change will probably break backward compatibility with compiled
28modules. The change was made to make Perl more compliant with other
29applications like modperl which are using the AIX native interface.
30
31=head2 Socket Extension Dynamic in VMS
32
33The Socket extension is now dynamically loaded instead of being
34statically built in. This may or may not be a problem with ancient
35TCP/IP stacks of VMS: we do not know since we weren't able to test
36Perl in such configurations.
37
38=head2 Different Definition of the Unicode Character Classes \p{In...}
39
40As suggested by the Unicode consortium, the Unicode character classes
41now prefer I<scripts> as opposed to I<blocks> (as defined by Unicode);
42in Perl, when the C<\p{In....}> and the C<\p{In....}> regular expression
43constructs are used. This has changed the definition of some of those
44character classes.
45
46The difference between scripts and blocks is that scripts are the
47glyphs used by a language or a group of languages, while the blocks
48are more artificial groupings of 256 characters based on the Unicode
49numbering.
50
51In general this change results in more inclusive Unicode character
52classes, but changes to the other direction also do take place:
53for example while the script C<Latin> includes all the Latin
54characters and their various diacritic-adorned versions, it
55does not include the various punctuation or digits (since they
56are not solely C<Latin>).
57
58Changes in the character class semantics may have happened if a script
59and a block happen to have the same name, for example C<Hebrew>.
60In such cases the script wins and C<\p{InHebrew}> now means the script
61definition of Hebrew. The block definition in still available,
62though, by appending C<Block> to the name: C<\p{InHebrewBlock}> means
63what C<\p{InHebrew}> meant in perl 5.6.0. For the full list
64of affected character classes, see L<perlunicode/Blocks>.
65
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66=head2 Perl Parser Stress Tested
67
68The Perl parser has been stress tested using both random input and
69Markov chain input and the few found crashes and lockups have been
70fixed.
71
c2e23569 72=head2 REF(...) Instead Of SCALAR(...)
77c8cf41 73
057b7f2b 74A reference to a reference now stringifies as "REF(0x81485ec)" instead
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75of "SCALAR(0x81485ec)" in order to be more consistent with the return
76value of ref().
77c8cf41 77
c2e23569 78=head2 Deprecations
77c8cf41 79
61947107 80=over 4
77c8cf41 81
61947107 82=item *
f39f21d8 83
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84The semantics of bless(REF, REF) were unclear and until someone proves
85it to make some sense, it is forbidden.
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86
87=item *
88
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89The obsolete chat2 library that should never have been allowed
90to escape the laboratory has been decommissioned.
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91
92=item *
93
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94The very dusty examples in the eg/ directory have been removed.
95Suggestions for new shiny examples welcome but the main issue is that
96the examples need to be documented, tested and (most importantly)
97maintained.
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98
99=item *
100
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101The (bogus) escape sequences \8 and \9 now give an optional warning
102("Unrecognized escape passed through"). There is no need to \-escape
103any C<\w> character.
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104
105=item *
106
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107The list of filenames from glob() (or <...>) is now by default sorted
108alphabetically to be csh-compliant. (bsd_glob() does still sort platform
109natively, ASCII or EBCDIC, unless GLOB_ALPHASORT is specified.)
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110
111=item *
112
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113Although "you shouldn't do that", it was possible to write code that
114depends on Perl's hashed key order (Data::Dumper does this). The new
115algorithm "One-at-a-Time" produces a different hashed key order.
116More details are in L</"Performance Enhancements">.
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117
118=item *
119
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120lstat(FILEHANDLE) now gives a warning because the operation makes no sense.
121In future releases this may become a fatal error.
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122
123=item *
124
057b7f2b 125The C<package;> syntax (C<package> without an argument) has been
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126deprecated. Its semantics were never that clear and its
127implementation even less so. If you have used that feature to
128disallow all but fully qualified variables, C<use strict;> instead.
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129
130=item *
131
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132The unimplemented POSIX regex features [[.cc.]] and [[=c=]] are still
133recognised but now cause fatal errors. The previous behaviour of
134ignoring them by default and warning if requested was unacceptable
135since it, in a way, falsely promised that the features could be used.
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136
137=item *
138
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139The current user-visible implementation of pseudo-hashes (the weird
140use of the first array element) is deprecated starting from Perl 5.8.0
141and will be removed in Perl 5.10.0, and the feature will be
142implemented differently. Not only is the current interface rather
143ugly, but the current implementation slows down normal array and hash
144use quite noticeably. The C<fields> pragma interface will remain
145available.
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146
147=item *
148
aecce728 149The syntaxes C<< @a->[...] >> and C<< %h->{...} >> have now been deprecated.
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150
151=item *
152
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153After years of trying the suidperl is considered to be too complex to
154ever be considered truly secure. The suidperl functionality is likely
155to be removed in a future release.
156
157=item *
158
159The long deprecated uppercase aliases for the string comparison
160operators (EQ, NE, LT, LE, GE, GT) have now been removed.
161
162=item *
163
164The tr///C and tr///U features have been removed and will not return;
165the interface was a mistake. Sorry about that. For similar
166functionality, see pack('U0', ...) and pack('C0', ...).
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167
168=back
169
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170=head1 Core Enhancements
171
77c8cf41 172=head2 PerlIO is Now The Default
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173
174=over 4
175
176=item *
177
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178IO is now by default done via PerlIO rather than system's "stdio".
179PerlIO allows "layers" to be "pushed" onto a file handle to alter the
180handle's behaviour. Layers can be specified at open time via 3-arg
181form of open:
f39f21d8 182
77c8cf41 183 open($fh,'>:crlf :utf8', $path) || ...
f39f21d8 184
77c8cf41 185or on already opened handles via extended C<binmode>:
f39f21d8 186
77c8cf41 187 binmode($fh,':encoding(iso-8859-7)');
f39f21d8 188
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189The built-in layers are: unix (low level read/write), stdio (as in
190previous Perls), perlio (re-implementation of stdio buffering in a
191portable manner), crlf (does CRLF <=> "\n" translation as on Win32,
192but available on any platform). A mmap layer may be available if
193platform supports it (mostly UNIXes).
f39f21d8 194
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195Layers to be applied by default may be specified via the 'open' pragma.
196
197See L</"Installation and Configuration Improvements"> for the effects
198of PerlIO on your architecture name.
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199
200=item *
201
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202File handles can be marked as accepting Perl's internal encoding of Unicode
203(UTF-8 or UTF-EBCDIC depending on platform) by a pseudo layer ":utf8" :
f39f21d8 204
77c8cf41 205 open($fh,">:utf8","Uni.txt");
f39f21d8 206
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207Note for EBCDIC users: the pseudo layer ":utf8" is erroneously named
208for you since it's not UTF-8 what you will be getting but instead
209UTF-EBCDIC. See L<perlunicode>, L<utf8>, and
210http://www.unicode.org/unicode/reports/tr16/ for more information.
211In future releases this naming may change.
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212
213=item *
214
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215File handles can translate character encodings from/to Perl's internal
216Unicode form on read/write via the ":encoding()" layer.
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217
218=item *
219
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220File handles can be opened to "in memory" files held in Perl scalars via:
221
222 open($fh,'>', \$variable) || ...
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223
224=item *
225
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226Anonymous temporary files are available without need to
227'use FileHandle' or other module via
f39f21d8 228
77c8cf41 229 open($fh,"+>", undef) || ...
f39f21d8 230
77c8cf41 231That is a literal undef, not an undefined value.
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232
233=item *
234
77c8cf41 235The list form of C<open> is now implemented for pipes (at least on UNIX):
f39f21d8 236
77c8cf41 237 open($fh,"-|", 'cat', '/etc/motd')
f39f21d8 238
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239creates a pipe, and runs the equivalent of exec('cat', '/etc/motd') in
240the child process.
f39f21d8 241
e1f170bd 242=back
f39f21d8 243
e1f170bd 244=head2 Signals Are Now Safe
f39f21d8 245
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246Perl used to be fragile in that signals arriving at inopportune moments
247could corrupt Perl's internal state. Now Perl postpones handling of
248signals until it's safe.
f39f21d8 249
e1f170bd 250=head2 Unicode Overhaul
f39f21d8 251
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252Unicode in general should be now much more usable than in Perl 5.6.0
253(or even in 5.6.1). Unicode can be used in hash keys, Unicode in
254regular expressions should work now, Unicode in tr/// should work now,
255Unicode in I/O should work now.
f39f21d8 256
e1f170bd 257=over 4
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258
259=item *
260
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261The Unicode Character Database coming with Perl has been upgraded
262to Unicode 3.1.1. For more information, see http://www.unicode.org/.
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263
264=item *
265
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266For developers interested in enhancing Perl's Unicode capabilities:
267almost all the UCD files are included with the Perl distribution in
e1f170bd 268the lib/unicore subdirectory. The most notable omission, for space
77c8cf41 269considerations, is the Unihan database.
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270
271=item *
272
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273The Unicode character classes \p{Blank} and \p{SpacePerl} have been
274added. "Blank" is like C isblank(), that is, it contains only
275"horizontal whitespace" (the space character is, the newline isn't),
276and the "SpacePerl" is the Unicode equivalent of C<\s> (\p{Space}
277isn't, since that includes the vertical tabulator character, whereas
278C<\s> doesn't.)
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279
280=back
281
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282=head2 Understanding of Numbers
283
284In general a lot of fixing has happened in the area of Perl's
285understanding of numbers, both integer and floating point. Since in
286many systems the standard number parsing functions like C<strtoul()>
287and C<atof()> seem to have bugs, Perl tries to work around their
288deficiencies. This results hopefully in more accurate numbers.
f39f21d8 289
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290Perl now tries internally to use integer values in numeric conversions
291and basic arithmetics (+ - * /) if the arguments are integers, and
292tries also to keep the results stored internally as integers.
057b7f2b 293This change leads to often slightly faster and always less lossy
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294arithmetics. (Previously Perl always preferred floating point numbers
295in its math.)
296
297=head2 Miscellaneous Enhancements
298
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299=over 4
300
301=item *
302
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303AUTOLOAD is now lvaluable, meaning that you can add the :lvalue attribute
304to AUTOLOAD subroutines and you can assign to the AUTOLOAD return value.
305
306=item *
307
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308C<perl -d:Module=arg,arg,arg> now works (previously one couldn't pass
309in multiple arguments.)
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310
311=item *
312
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313END blocks are now run even if you exit/die in a BEGIN block.
314Internally, the execution of END blocks is now controlled by
315PL_exit_flags & PERL_EXIT_DESTRUCT_END. This enables the new
316behaviour for Perl embedders. This will default in 5.10. See
317L<perlembed>.
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318
319=item *
320
e1f170bd 321Formats now support zero-padded decimal fields.
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322
323=item *
324
77c8cf41 325Lvalue subroutines can now return C<undef> in list context.
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326
327=item *
328
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329A new special regular expression variable has been introduced:
330C<$^N>, which contains the most-recently closed group (submatch).
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331
332=item *
333
61947107 334C<no Module;> now works even if there is no "sub unimport" in the Module.
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335
336=item *
337
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338The numerical comparison operators return C<undef> if either operand
339is a NaN. Previously the behaviour was unspecified.
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340
341=item *
342
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343The following builtin functions are now overridable: each(), keys(),
344pop(), push(), shift(), splice(), unshift().
345
346=item *
347
61947107 348C<pack('U0a*', ...)> can now be used to force a string to UTF8.
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349
350=item *
351
61947107 352my __PACKAGE__ $obj now works.
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353
354=item *
355
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356The printf() and sprintf() now support parameter reordering using the
357C<%\d+\$> and C<*\d+\$> syntaxes. For example
358
359 print "%2\$s %1\$s\n", "foo", "bar";
360
361will print "bar foo\n"; This feature helps in writing
362internationalised software.
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363
364=item *
365
e1f170bd 366prototype(\&) is now available.
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367
368=item *
369
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370prototype(\[$@%&]) is now available to implicitly create references
371(useful for example if you want to emulate the tie() interface).
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372
373=item *
374
e1f170bd 375UNTIE method is now recognised.
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376
377=item *
378
379L<utime> now supports C<utime undef, undef, @files> to change the
380file timestamps to the current time.
381
382=item *
383
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384The rules for allowing underscores (underbars) in numeric constants
385have been relaxed and simplified: now you can have an underscore
386simply B<between digits>.
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387
388=back
389
77c8cf41 390=head1 Modules and Pragmata
f39f21d8 391
1e13d81f 392=head2 New Modules and Pragmata
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393
394=over 4
395
396=item *
397
61947107 398C<Attribute::Handlers> allows a class to define attribute handlers.
f39f21d8 399
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400 package MyPack;
401 use Attribute::Handlers;
402 sub Wolf :ATTR(SCALAR) { print "howl!\n" }
f39f21d8 403
61947107 404 # later, in some package using or inheriting from MyPack...
f39f21d8 405
61947107 406 my MyPack $Fluffy : Wolf; # the attribute handler Wolf will be called
ba370e9b 407
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408Both variables and routines can have attribute handlers. Handlers can
409be specific to type (SCALAR, ARRAY, HASH, or CODE), or specific to the
410exact compilation phase (BEGIN, CHECK, INIT, or END).
f39f21d8 411
61947107 412=item *
f39f21d8 413
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414B<B::Concise> is a new compiler backend for walking the Perl syntax
415tree, printing concise info about ops, from Stephen McCamant. The
416output is highly customisable. See L<B::Concise>.
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417
418=item *
419
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420C<Class::ISA> for reporting the search path for a class's ISA tree,
421by Sean Burke, has been added. See L<Class::ISA>.
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422
423=item *
424
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425C<Cwd> has now a split personality: if possible, an XS extension is
426used, (this will hopefully be faster, more secure, and more robust)
427but if not possible, the familiar Perl implementation is used.
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428
429=item *
430
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431C<Devel::PPPort>, originally from Kenneth Albanowski and now
432maintained by Paul Marquess, has been added. It is primarily used
433by C<h2xs> to enhance portability of of XS modules between different
434versions of Perl.
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435
436=item *
437
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438C<Digest>, frontend module for calculating digests (checksums), from
439Gisle Aas, has been added. See L<Digest>.
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440
441=item *
442
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443C<Digest::MD5> for calculating MD5 digests (checksums) as defined in
444RFC 1321, from Gisle Aas, has been added. See L<Digest::MD5>.
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445
446 use Digest::MD5 'md5_hex';
447
448 $digest = md5_hex("Thirsty Camel");
449
450 print $digest, "\n"; # 01d19d9d2045e005c3f1b80e8b164de1
451
61947107 452NOTE: the C<MD5> backward compatibility module is deliberately not
e1f170bd 453included since its further use is discouraged.
f39f21d8 454
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455=item *
456
61947107 457C<Encode>, by Nick Ing-Simmons, provides a mechanism to translate
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458between different character encodings. Support for Unicode,
459ISO-8859-*, ASCII, CP*, KOI8-R, and three variants of EBCDIC are
460compiled in to the module. Several other encodings (like Japanese,
461Chinese, and MacIntosh encodings) are included and will be loaded at
61947107 462runtime. See L<Encode>.
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463
464Any encoding supported by Encode module is also available to the
465":encoding()" layer if PerlIO is used.
466
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467=item *
468
469C<I18N::Langinfo> can be use to query locale information.
470See L<I18N::Langinfo>.
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471
472=item *
473
61947107 474C<I18N::LangTags> has functions for dealing with RFC3066-style
bea4d472 475language tags, by Sean Burke. See L<I18N::LangTags>.
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476
477=item *
478
479C<ExtUtils::Constant> is a new tool for extension writers for
480generating XS code to import C header constants, by Nicholas Clark.
481See L<ExtUtils::Constant>.
482
483=item *
484
485C<Filter::Simple> is an easy-to-use frontend to Filter::Util::Call,
486from Damian Conway. See L<Filter::Simple>.
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487
488 # in MyFilter.pm:
489
490 package MyFilter;
491
492 use Filter::Simple sub {
493 while (my ($from, $to) = splice @_, 0, 2) {
494 s/$from/$to/g;
495 }
496 };
497
498 1;
499
500 # in user's code:
501
502 use MyFilter qr/red/ => 'green';
503
504 print "red\n"; # this code is filtered, will print "green\n"
505 print "bored\n"; # this code is filtered, will print "bogreen\n"
506
507 no MyFilter;
508
509 print "red\n"; # this code is not filtered, will print "red\n"
510
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511=item *
512
513C<File::Temp> allows one to create temporary files and directories in
514an easy, portable, and secure way, by Tim Jenness. See L<File::Temp>.
515
516=item *
517
518C<Filter::Util::Call> provides you with the framework to write
519I<Source Filters> in Perl, from Paul Marquess. For most uses the
520frontend Filter::Simple is to be preferred. See L<Filter::Util::Call>.
521
522=item *
523
524L<libnet> is a collection of perl5 modules related to network
525programming, from Graham Barr. See L<Net::FTP>, L<Net::NNTP>,
526L<Net::Ping>, L<Net::POP3>, L<Net::SMTP>, and L<Net::Time>.
527
528Perl installation leaves libnet unconfigured, use F<libnetcfg> to configure.
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529
530=item *
531
61947107 532C<List::Util> is a selection of general-utility list subroutines, like
bea4d472 533sum(), min(), first(), and shuffle(), by Graham Barr. See L<List::Util>.
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534
535=item *
536
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537C<Locale::Constants>, C<Locale::Country>, C<Locale::Currency>, and
538C<Locale::Language>, from Neil Bowers, have been added. They provide the
539codes for various locale standards, such as "fr" for France, "usd" for
540US Dollar, and "jp" for Japanese.
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541
542 use Locale::Country;
543
544 $country = code2country('jp'); # $country gets 'Japan'
545 $code = country2code('Norway'); # $code gets 'no'
546
547See L<Locale::Constants>, L<Locale::Country>, L<Locale::Currency>,
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548and L<Locale::Language>.
549
550=item *
551
552C<Locale::Maketext> is localization framework from Sean Burke. See
553L<Locale::Maketext>, and L<Locale::Maketext::TPJ13>. The latter is an
554article about software localization, originally published in The Perl
555Journal #13, republished here with kind permission.
556
557=item *
558
559C<Memoize> can make your functions faster by trading space for time,
560from Mark-Jason Dominus. See L<Memoize>.
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561
562=item *
563
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564C<MIME::Base64> allows you to encode data in base64, from Gisle Aas,
565as defined in RFC 2045 - I<MIME (Multipurpose Internet Mail
566Extensions)>.
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567
568 use MIME::Base64;
569
570 $encoded = encode_base64('Aladdin:open sesame');
571 $decoded = decode_base64($encoded);
572
573 print $encoded, "\n"; # "QWxhZGRpbjpvcGVuIHNlc2FtZQ=="
574
61947107 575See L<MIME::Base64>.
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576
577=item *
578
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579C<MIME::QuotedPrint> allows you to encode data in quoted-printable
580encoding, as defined in RFC 2045 - I<MIME (Multipurpose Internet Mail
581Extensions)>, from Gisle Aas.
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582
583 use MIME::QuotedPrint;
584
585 $encoded = encode_qp("Smiley in Unicode: \x{263a}");
586 $decoded = decode_qp($encoded);
587
588 print $encoded, "\n"; # "Smiley in Unicode: =263A"
589
590MIME::QuotedPrint has been enhanced to provide the basic methods
591necessary to use it with PerlIO::Via as in :
592
593 use MIME::QuotedPrint;
057b7f2b 594 open($fh,">Via(MIME::QuotedPrint)",$path);
f39f21d8 595
61947107 596See L<MIME::QuotedPrint>.
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597
598=item *
599
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600C<NEXT> is pseudo-class for method redispatch, from Damian Conway.
601See L<NEXT>.
f39f21d8
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602
603=item *
604
1e13d81f
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605C<open> is a new pragma for setting the default I/O disciplines
606for open().
607
608=item *
609
61947107
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610C<PerlIO::Scalar> provides the implementation of IO to "in memory"
611Perl scalars as discussed above, from Nick Ing-Simmons. It also
612serves as an example of a loadable PerlIO layer. Other future
613possibilities include PerlIO::Array and PerlIO::Code.
614See L<PerlIO::Scalar>.
615
616=item *
617
618C<PerlIO::Via> acts as a PerlIO layer and wraps PerlIO layer
619functionality provided by a class (typically implemented in perl
620code), from Nick Ing-Simmons.
f39f21d8
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621
622 use MIME::QuotedPrint;
057b7f2b 623 open($fh,">Via(MIME::QuotedPrint)",$path);
f39f21d8
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624
625This will automatically convert everything output to C<$fh>
61947107 626to Quoted-Printable. See L<PerlIO::Via>.
f39f21d8
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627
628=item *
629
1e13d81f 630C<Pod::ParseLink>, by Russ Allbery, has been added,
e1f170bd 631to parse L&lt;&gt; links in pods as described in the new
1e13d81f
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632perlpodspec.
633
634=item *
635
61947107 636C<Pod::Text::Overstrike>, by Joe Smith, has been added.
f39f21d8 637It converts POD data to formatted overstrike text.
61947107 638See L<Pod::Text::Overstrike>.
f39f21d8
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639
640=item *
641
61947107
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642C<Scalar::Util> is a selection of general-utility scalar subroutines,
643like blessed(), reftype(), and tainted(). See L<Scalar::Util>.
644
645=item *
646
1e13d81f
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647C<sort> is a new pragma for controlling the behaviour of sort().
648
649=item *
650
61947107
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651C<Storable> gives persistence to Perl data structures by allowing the
652storage and retrieval of Perl data to and from files in a fast and
653compact binary format, from Raphael Manfredi. See L<Storable>.
654
655=item *
656
657C<Switch>, from Damian Conway, has been added. Just by saying
f39f21d8
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658
659 use Switch;
660
661you have C<switch> and C<case> available in Perl.
662
663 use Switch;
664
665 switch ($val) {
666
667 case 1 { print "number 1" }
668 case "a" { print "string a" }
669 case [1..10,42] { print "number in list" }
670 case (@array) { print "number in list" }
671 case /\w+/ { print "pattern" }
672 case qr/\w+/ { print "pattern" }
673 case (%hash) { print "entry in hash" }
674 case (\%hash) { print "entry in hash" }
675 case (\&sub) { print "arg to subroutine" }
676 else { print "previous case not true" }
677 }
678
61947107
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679See L<Switch>.
680
681=item *
682
683C<Test::More> is yet another framework for writing test scripts,
684more extensive than Test::Simple, by Michael Schwern. See L<Test::More>.
685
686=item *
687
aecce728 688C<Test::Simple> has basic utilities for writing tests, by Michael
61947107 689Schwern. See L<Test::Simple>.
77c8cf41
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690
691=item *
692
61947107
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693C<Text::Balanced> has been added, for extracting delimited text
694sequences from strings, from Damian Conway.
77c8cf41
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695
696 use Text::Balanced 'extract_delimited';
697
698 ($a, $b) = extract_delimited("'never say never', he never said", "'", '');
699
700$a will be "'never say never'", $b will be ', he never said'.
701
702In addition to extract_delimited() there are also extract_bracketed(),
703extract_quotelike(), extract_codeblock(), extract_variable(),
704extract_tagged(), extract_multiple(), gen_delimited_pat(), and
705gen_extract_tagged(). With these you can implement rather advanced
61947107 706parsing algorithms. See L<Text::Balanced>.
77c8cf41
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707
708=item *
709
c2e23569 710C<threads> is an interface to interpreter threads, by Arthur Bergman.
61947107 711Interpreter threads (ithreads) is the new thread model introduced in
c2e23569
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712Perl 5.6 but only available as an internal interface for extension
713writers (and for Win32 Perl for C<fork()> emulation). See L<threads>.
77c8cf41
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714
715=item *
716
61947107
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717C<threads::shared> allows data sharing for interpreter threads, from
718Arthur Bergman. In the ithreads model any data sharing between
719threads must be explicit, as opposed to the old 5.005 thread model
720where data sharing was implicit. See L<threads::shared>.
77c8cf41
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721
722=item *
723
61947107 724C<Tie::RefHash::Nestable>, by Edward Avis, allows storing hash
ba370e9b
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725references (unlike the standard Tie::RefHash) The module is contained
726within Tie::RefHash, see L<Tie::RefHash>.
77c8cf41
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727
728=item *
729
61947107
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730C<Time::HiRes> provides high resolution timing (ualarm, usleep,
731and gettimeofday), from Douglas E. Wegscheid. See L<Time::HiRes>.
77c8cf41
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732
733=item *
734
61947107
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735C<Unicode::UCD> offers a querying interface to the Unicode Character
736Database. See L<Unicode::UCD>.
77c8cf41
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737
738=item *
739
61947107
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740C<Unicode::Collate> implements the UCA (Unicode Collation Algorithm)
741for sorting Unicode strings, by SADAHIRO Tomoyuki. See L<Unicode::Collate>.
77c8cf41
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742
743=item *
744
61947107
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745C<Unicode::Normalize> implements the various Unicode normalization
746forms, by SADAHIRO Tomoyuki. See L<Unicode::Normalize>.
77c8cf41
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747
748=item *
749
61947107
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750C<XS::Typemap>, by Tim Jenness, is a test extension that exercises XS
751typemaps. Nothing gets installed but for extension writers the code
752is worth studying.
77c8cf41
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753
754=back
755
756=head2 Updated And Improved Modules and Pragmata
757
758=over 4
759
760=item *
761
61947107
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762The following independently supported modules have been updated to the
763newest versions from CPAN: CGI, CPAN, DB_File, File::Spec, File::Temp,
764Getopt::Long, Math::BigFloat, Math::BigInt, the podlators bundle
765(Pod::Man, Pod::Text), Pod::LaTeX, Pod::Parser, Storable,
766Term::ANSIColor, Test, Text-Tabs+Wrap.
77c8cf41
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767
768=item *
769
61947107 770The attributes::reftype() now works on tied arguments.
77c8cf41
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771
772=item *
773
057b7f2b 774AutoLoader can now be disabled with C<no AutoLoader;>.
77c8cf41
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775
776=item *
777
1e13d81f
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778B::Deparse has been significantly enhanced. It now can deparse almost
779all of the standard test suite (so that the tests still succeed).
780There is a make target "test.deparse" for trying this out.
77c8cf41
JH
781
782=item *
783
1e13d81f 784Class::Struct can now define the classes in compile time.
77c8cf41
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785
786=item *
787
1e13d81f
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788Class::Struct now assigns the array/hash element if the accessor
789is called with an array/hash element as the B<sole> argument.
77c8cf41
JH
790
791=item *
792
1e13d81f 793Data::Dumper has now an option to sort hashes.
77c8cf41
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794
795=item *
796
1e13d81f
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797Data::Dumper has now an option to dump code references
798using B::Deparse.
77c8cf41
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799
800=item *
801
1e13d81f
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802The English module can now be used without the infamous performance
803hit by saying
77c8cf41 804
1e13d81f 805 use English '-no_performance_hit';
77c8cf41 806
1e13d81f
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807(Assuming, of course, that one doesn't need the troublesome variables
808C<$`>, C<$&>, or C<$'>.) Also, introduced C<@LAST_MATCH_START> and
809C<@LAST_MATCH_END> English aliases for C<@-> and C<@+>.
77c8cf41
JH
810
811=item *
812
1e13d81f
JH
813Fcntl, Socket, and Sys::Syslog have been rewritten to use the
814new-style constant dispatch section (see L<ExtUtils::Constant>).
815This means that they will be more robust and hopefully faster.
77c8cf41
JH
816
817=item *
818
1e13d81f
JH
819File::Find now has pre- and post-processing callbacks. It also
820correctly changes directories when chasing symbolic links. Callbacks
821(naughtily) exiting with "next;" instead of "return;" now work.
61947107
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822
823=item *
824
1e13d81f
JH
825File::Find is now (again) reentrant. It also has been made
826more portable.
77c8cf41 827
61947107
JH
828=item *
829
1e13d81f
JH
830File::Glob::glob() renamed to File::Glob::bsd_glob() to avoid
831prototype mismatch with CORE::glob().
61947107
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832
833=item *
834
835File::Glob now supports C<GLOB_LIMIT> constant to limit the size of
836the returned list of filenames.
77c8cf41
JH
837
838=item *
839
840Devel::Peek now has an interface for the Perl memory statistics
841(this works only if you are using perl's malloc, and if you have
842compiled with debugging).
843
844=item *
845
1e13d81f
JH
846IPC::Open3 now allows the use of numeric file descriptors.
847
848=item *
849
77c8cf41
JH
850IO::Socket has now atmark() method, which returns true if the socket
851is positioned at the out-of-band mark. The method is also exportable
852as a sockatmark() function.
853
854=item *
855
856IO::Socket::INET has support for ReusePort option (if your platform
857supports it). The Reuse option now has an alias, ReuseAddr. For clarity
858you may want to prefer ReuseAddr.
859
860=item *
861
61947107
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862IO::Socket::INET now supports C<LocalPort> of zero (usually meaning
863that the operating system will make one up.)
77c8cf41
JH
864
865=item *
866
1e13d81f
JH
867use lib now works identically to @INC. Removing directories
868with 'no lib' now works.
869
870=item *
871
872Math::BigFloat and Math::BigInt have undergone a full rewrite.
873They are now magnitudes faster, and they support various
61947107 874bignum libraries such as GMP and PARI as their backends.
f39f21d8
JH
875
876=item *
877
61947107
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878Net::Ping has been enhanced. There is now "external" protocol which
879uses Net::Ping::External module which runs external ping(1) and parses
880the output. An alpha version of Net::Ping::External is available in
881CPAN and in 5.7.2 the Net::Ping::External may be integrated to Perl.
f39f21d8 882
77c8cf41 883=item *
f39f21d8 884
c2e23569 885C<POSIX::sigaction()> is now much more flexible and robust.
61947107
JH
886You can now install coderef handlers, 'DEFAULT', and 'IGNORE'
887handlers, installing new handlers was not atomic.
f39f21d8
JH
888
889=item *
890
1e13d81f
JH
891C<%INC> now localised in a Safe compartment so that use/require work.
892
893=item *
894
895The Shell module now has an OO interface.
896
897=item *
898
61947107 899The Test module has been significantly enhanced.
f39f21d8
JH
900
901=item *
902
61947107 903The C<vars> pragma now supports declaring fully qualified variables.
77c8cf41 904(Something that C<our()> does not and will not support.)
f39f21d8 905
888aee59
JH
906=item *
907
61947107
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908The utf8:: name space (as in the pragma) provides various
909Perl-callable functions to provide low level access to Perl's
910internal Unicode representation. At the moment only length()
911has been implemented.
888aee59 912
f39f21d8
JH
913=back
914
77c8cf41 915=head1 Utility Changes
f39f21d8
JH
916
917=over 4
918
919=item *
920
61947107 921Emacs perl mode (emacs/cperl-mode.el) has been updated to version
77c8cf41 9224.31.
f39f21d8
JH
923
924=item *
925
61947107 926F<emacs/e2ctags.pl> is now much faster.
f39f21d8
JH
927
928=item *
929
1e13d81f
JH
930C<h2ph> now supports C trigraphs.
931
932=item *
933
934C<h2xs> now produces a template README.
f39f21d8 935
77c8cf41
JH
936=item *
937
1e13d81f
JH
938C<h2xs> now uses C<Devel::PPort> for better portability between
939different versions of Perl.
f39f21d8
JH
940
941=item *
942
1e13d81f 943C<h2xs> uses the new L<ExtUtils::Constant> module which will affect
61947107
JH
944newly created extensions that define constants. Since the new code is
945more correct (if you have two constants where the first one is a
946prefix of the second one, the first constant B<never> gets defined),
947less lossy (it uses integers for integer constant, as opposed to the
948old code that used floating point numbers even for integer constants),
949and slightly faster, you might want to consider regenerating your
950extension code (the new scheme makes regenerating easy).
951L<h2xs> now also supports C trigraphs.
f39f21d8
JH
952
953=item *
954
1e13d81f 955C<libnetcfg> has been added to configure the libnet.
f39f21d8
JH
956
957=item *
958
1e13d81f 959C<perlbug> is now much more robust. It also sends the bug report to
61947107 960perl.org, not perl.com.
f39f21d8
JH
961
962=item *
963
1e13d81f 964C<perlcc> has been rewritten and its user interface (that is,
61947107 965command line) is much more like that of the UNIX C compiler, cc.
f39f21d8
JH
966
967=item *
968
aecce728
JH
969C<perlivp> is a new Installation Verification Procedure utility
970for running any time after installing Perl.
f39f21d8
JH
971
972=item *
973
1e13d81f 974C<pod2html> now allows specifying a cache directory.
f39f21d8
JH
975
976=item *
977
1e13d81f
JH
978C<s2p> has been completely rewritten in Perl. (It is in fact a full
979implementation of sed in Perl: you can use the sed functionality by
980using the C<psed> utility.)
61947107
JH
981
982=item *
983
1e13d81f 984C<xsubpp> now understands POD documentation embedded in the *.xs files.
f39f21d8
JH
985
986=item *
987
1e13d81f 988C<xsubpp> now supports OUT keyword.
f39f21d8
JH
989
990=back
991
77c8cf41 992=head1 New Documentation
f39f21d8
JH
993
994=over 4
995
996=item *
997
77c8cf41
JH
998perl56delta details the changes between the 5.005 release and the
9995.6.0 release.
f39f21d8
JH
1000
1001=item *
1002
61947107
JH
1003perlclib documents the internal replacements for standard C library
1004functions. (Interesting only for extension writers and Perl core
1005hackers.)
1006
1007=item *
1008
77c8cf41 1009perldebtut is a Perl debugging tutorial.
f39f21d8 1010
77c8cf41 1011=item *
f39f21d8 1012
77c8cf41 1013perlebcdic contains considerations for running Perl on EBCDIC platforms.
f39f21d8 1014
77c8cf41
JH
1015=item *
1016
888aee59
JH
1017perlintro is a gentle introduction to Perl.
1018
1019=item *
1020
61947107
JH
1021perliol documents the internals of PerlIO with layers.
1022
1023=item *
1024
888aee59
JH
1025perlmodstyle is a style guide for writing modules.
1026
1027=item *
1028
77c8cf41 1029perlnewmod tells about writing and submitting a new module.
f39f21d8
JH
1030
1031=item *
1032
34babc16
JH
1033perlpacktut is a pack() tutorial.
1034
1035=item *
1036
888aee59
JH
1037perlpod has been rewritten to be clearer and to record the best
1038practices gathered over the years.
1039
1040=item *
1041
057b7f2b 1042perlpodspec is a more formal specification of the pod format,
888aee59
JH
1043mainly of interest for writers of pod applications, not to
1044people writing in pod.
1045
1046=item *
1047
77c8cf41 1048perlretut is a regular expression tutorial.
f39f21d8
JH
1049
1050=item *
1051
77c8cf41
JH
1052perlrequick is a regular expressions quick-start guide.
1053Yes, much quicker than perlretut.
f39f21d8 1054
77c8cf41 1055=item *
f39f21d8 1056
61947107
JH
1057perltodo has been updated.
1058
1059=item *
1060
888aee59 1061perltootc has been renamed as perltooc (to not to conflict
61947107 1062with perltoot in filesystems restricted to "8.3" names)
888aee59
JH
1063
1064=item *
1065
1066perluniintro is an introduction to using Unicode in Perl
1067(perlunicode is more of a reference)
1068
1069=item *
1070
77c8cf41
JH
1071perlutil explains the command line utilities packaged with the Perl
1072distribution.
1073
1074=back
f39f21d8 1075
61947107
JH
1076The following platform-specific documents are available before
1077the installation as README.I<platform>, and after the installation
1078as perlI<platform>:
f39f21d8 1079
61947107
JH
1080 perlaix perlamiga perlapollo perlbeos perlbs2000
1081 perlce perlcygwin perldgux perldos perlepoc perlhpux
1082 perlhurd perlmachten perlmacos perlmint perlmpeix
1083 perlnetware perlos2 perlos390 perlplan9 perlqnx perlsolaris
1084 perltru64 perluts perlvmesa perlvms perlvos perlwin32
77c8cf41
JH
1085
1086=over 4
1087
1088=item *
1089
61947107
JH
1090The documentation for the POSIX-BC platform is called "BS2000", to avoid
1091confusion with the Perl POSIX module.
77c8cf41
JH
1092
1093=item *
1094
61947107
JH
1095The documentation for the WinCE platform is called "CE", to avoid
1096confusion with the perlwin32 documentation on 8.3-restricted filesystems.
77c8cf41
JH
1097
1098=back
1099
1100=head1 Performance Enhancements
1101
1102=over 4
1103
1104=item *
1105
1106map() that changes the size of the list should now work faster.
1107
1108=item *
1109
e1f170bd
JH
1110sort() has been changed to use primarily mergesort internally as
1111opposed to the earlier quicksort. For very small lists this may
1112result in slightly slower sorting times, but in general the speedup
1113should be at least 20%. Additional bonuses are that the worst case
1114behaviour of sort() is now better (in computer science terms it now
1115runs in time O(N log N), as opposed to quicksort's Theta(N**2)
1116worst-case run time behaviour), and that sort() is now stable
1117(meaning that elements with identical keys will stay ordered as they
1118were before the sort). See the C<sort> pragma for information.
77c8cf41 1119
05e25c75
JH
1120The story in more detail: suppose you want to serve yourself a little
1121slice of Pi.
1122
1123 @digits = ( 3,1,4,1,5,9 );
1124
1125A numerical sort of the digits will yield (1,1,3,4,5,9), as expected.
1126Which C<1> comes first is hard to know, since one C<1> looks pretty
1127much like any other. You can regard this as totally trivial,
1128or somewhat profound. However, if you just want to sort the even
1129digits ahead of the odd ones, then what will
1130
1131 sort { ($a % 2) <=> ($b % 2) } @digits;
1132
1133yield? The only even digit, C<4>, will come first. But how about
1134the odd numbers, which all compare equal? With the quicksort algorithm
1135used to implement Perl 5.6 and earlier, the order of ties is left up
1136to the sort. So, as you add more and more digits of Pi, the order
1137in which the sorted even and odd digits appear will change.
1138and, for sufficiently large slices of Pi, the quicksort algorithm
1139in Perl 5.8 won't return the same results even if reinvoked with the
1140same input. The justification for this rests with quicksort's
1141worst case behavior. If you run
1142
1143 sort { $a <=> $b } ( 1 .. $N , 1 .. $N );
1144
1145(something you might approximate if you wanted to merge two sorted
1146arrays using sort), doubling $N doesn't just double the quicksort time,
1147it I<quadruples> it. Quicksort has a worst case run time that can
1148grow like N**2, so-called I<quadratic> behaviour, and it can happen
1149on patterns that may well arise in normal use. You won't notice this
1150for small arrays, but you I<will> notice it with larger arrays,
1151and you may not live long enough for the sort to complete on arrays
1152of a million elements. So the 5.8 quicksort scrambles large arrays
1153before sorting them, as a statistical defence against quadratic behaviour.
1154But that means if you sort the same large array twice, ties may be
1155broken in different ways.
1156
1157Because of the unpredictability of tie-breaking order, and the quadratic
1158worst-case behaviour, quicksort was I<almost> replaced completely with
1159a stable mergesort. I<Stable> means that ties are broken to preserve
1160the original order of appearance in the input array. So
1161
1162 sort { ($a % 2) <=> ($b % 2) } (3,1,4,1,5,9);
1163
1164will yield (4,3,1,1,5,9), guaranteed. The even and odd numbers
1165appear in the output in the same order they appeared in the input.
1166Mergesort has worst case O(NlogN) behaviour, the best value
1167attainable. And, ironically, this mergesort does particularly
1168well where quicksort goes quadratic: mergesort sorts (1..$N, 1..$N)
1169in O(N) time. But quicksort was rescued at the last moment because
1170it is faster than mergesort on certain inputs and platforms.
1171For example, if you really I<don't> care about the order of even
1172and odd digits, quicksort will run in O(N) time; it's very good
1173at sorting many repetitions of a small number of distinct elements.
1174The quicksort divide and conquer strategy works well on platforms
1175with relatively small, very fast, caches. Eventually, the problem gets
1176whittled down to one that fits in the cache, from which point it
1177benefits from the increased memory speed.
1178
1179Quicksort was rescued by implementing a sort pragma to control aspects
1180of the sort. The B<stable> subpragma forces stable behaviour,
1181regardless of algorithm. The B<_quicksort> and B<_mergesort>
1182subpragmas are heavy-handed ways to select the underlying implementation.
1183The leading C<_> is a reminder that these subpragmas may not survive
1184beyond 5.8. More appropriate mechanisms for selecting the implementation
1185exist, but they wouldn't have arrived in time to save quicksort.
1186
77c8cf41
JH
1187=item *
1188
1189Hashes now use Bob Jenkins "One-at-a-Time" hashing key algorithm
1190(http://burtleburtle.net/bob/hash/doobs.html). This algorithm is
1191reasonably fast while producing a much better spread of values than
1192the old hashing algorithm (originally by Chris Torek, later tweaked by
1193Ilya Zakharevich). Hash values output from the algorithm on a hash of
1194all 3-char printable ASCII keys comes much closer to passing the
1195DIEHARD random number generation tests. According to perlbench, this
1196change has not affected the overall speed of Perl.
1197
1198=item *
1199
1200unshift() should now be noticeably faster.
1201
1202=back
1203
1204=head1 Installation and Configuration Improvements
1205
1206=head2 Generic Improvements
1207
1208=over 4
1209
1210=item *
1211
1212INSTALL now explains how you can configure Perl to use 64-bit
1213integers even on non-64-bit platforms.
1214
1215=item *
1216
1217Policy.sh policy change: if you are reusing a Policy.sh file
1218(see INSTALL) and you use Configure -Dprefix=/foo/bar and in the old
1219Policy $prefix eq $siteprefix and $prefix eq $vendorprefix, all of
1220them will now be changed to the new prefix, /foo/bar. (Previously
1221only $prefix changed.) If you do not like this new behaviour,
1222specify prefix, siteprefix, and vendorprefix explicitly.
1223
1224=item *
1225
1226A new optional location for Perl libraries, otherlibdirs, is available.
1227It can be used for example for vendor add-ons without disturbing Perl's
1228own library directories.
1229
1230=item *
1231
1232In many platforms the vendor-supplied 'cc' is too stripped-down to
1233build Perl (basically, 'cc' doesn't do ANSI C). If this seems
1234to be the case and 'cc' does not seem to be the GNU C compiler
1235'gcc', an automatic attempt is made to find and use 'gcc' instead.
1236
1237=item *
1238
1239gcc needs to closely track the operating system release to avoid
1240build problems. If Configure finds that gcc was built for a different
1241operating system release than is running, it now gives a clearly visible
1242warning that there may be trouble ahead.
1243
1244=item *
1245
1246If binary compatibility with the 5.005 release is not wanted, Configure
1247no longer suggests including the 5.005 modules in @INC.
1248
1249=item *
1250
1251Configure C<-S> can now run non-interactively.
1252
1253=item *
1254
1255configure.gnu now works with options with whitespace in them.
f39f21d8 1256
77c8cf41 1257=item *
f39f21d8 1258
77c8cf41 1259installperl now outputs everything to STDERR.
f39f21d8 1260
77c8cf41
JH
1261=item *
1262
1263$Config{byteorder} is now computed dynamically (this is more robust
1264with "fat binaries" where an executable image contains binaries for
1265more than one binary platform.)
f39f21d8
JH
1266
1267=item *
1268
1269Because PerlIO is now the default on most platforms, "-perlio" doesn't
1270get appended to the $Config{archname} (also known as $^O) anymore.
1271Instead, if you explicitly choose not to use perlio (Configure command
1272line option -Uuseperlio), you will get "-stdio" appended.
1273
1274=item *
1275
1276Another change related to the architecture name is that "-64all"
1277(-Duse64bitall, or "maximally 64-bit") is appended only if your
1278pointers are 64 bits wide. (To be exact, the use64bitall is ignored.)
1279
1280=item *
1281
77c8cf41
JH
1282In AFS installations one can configure the root of the AFS to be
1283somewhere else than the default F</afs> by using the Configure
1284parameter C<-Dafsroot=/some/where/else>.
1285
1286=item *
1287
61947107
JH
1288APPLLIB_EXP, a less-know configuration-time definition, has been
1289documented. It can be used to prepend site-specific directories
1290to Perl's default search path (@INC), see INSTALL for information.
1291
1292=item *
1293
77c8cf41
JH
1294The version of Berkeley DB used when the Perl (and, presumably, the
1295DB_File extension) was built is now available as
1296C<@Config{qw(db_version_major db_version_minor db_version_patch)}>
1297from Perl and as C<DB_VERSION_MAJOR_CFG DB_VERSION_MINOR_CFG
1298DB_VERSION_PATCH_CFG> from C.
1299
1300=item *
1301
61947107
JH
1302Building Berkeley DB3 for compatibility modes for DB, NDBM, and ODBM
1303has been documented in INSTALL.
77c8cf41
JH
1304
1305=item *
1306
61947107
JH
1307If you have CPAN access (either network or a local copy such as a
1308CD-ROM) you can during specify extra modules to Configure to build and
1309install with Perl using the -Dextras=... option. See INSTALL for
1310more details.
f39f21d8 1311
61947107 1312=item *
f39f21d8 1313
61947107
JH
1314In addition to config.over a new override file, config.arch, is
1315available. That is supposed to be used by hints file writers for
1316architecture-wide changes (as opposed to config.over which is for
1317site-wide changes).
f39f21d8
JH
1318
1319=item *
1320
e1f170bd
JH
1321If your file system supports symbolic links you can build Perl outside
1322of the source directory by
1323
1324 mkdir /tmp/perl/build/directory
1325 cd /tmp/perl/build/directory
1326 sh /path/to/perl/source/Configure -Dmksymlinks ...
1327
1328This will create in /tmp/perl/build/directory a tree of symbolic links
1329pointing to files in /path/to/perl/source. The original files are left
1330unaffected. After Configure has finished you can just say
1331
1332 make all test
1333
1334and Perl will be built and tested, all in /tmp/perl/build/directory.
1335
1336=item *
1337
61947107
JH
1338For Perl developers several new make targets for profiling
1339and debugging have been added, see L<perlhack>.
1340
1341=over 8
f39f21d8
JH
1342
1343=item *
1344
61947107
JH
1345Use of the F<gprof> tool to profile Perl has been documented in
1346L<perlhack>. There is a make target called "perl.gprof" for
1347generating a gprofiled Perl executable.
f39f21d8
JH
1348
1349=item *
1350
61947107
JH
1351If you have GCC 3, there is a make target called "perl.gcov" for
1352creating a gcoved Perl executable for coverage analysis. See
1353L<perlhack>.
f39f21d8
JH
1354
1355=item *
1356
61947107
JH
1357If you are on IRIX or Tru64 platforms, new profiling/debugging options
1358have been added, see L<perlhack> for more information about pixie and
1359Third Degree.
1360
1361=back
f39f21d8
JH
1362
1363=item *
1364
61947107
JH
1365Guidelines of how to construct minimal Perl installations have
1366been added to INSTALL.
f39f21d8
JH
1367
1368=item *
1369
61947107
JH
1370The Thread extension is now not built at all under ithreads
1371(C<Configure -Duseithreads>) because it wouldn't work anyway (the
1372Thread extension requires being Configured with C<-Duse5005threads>).
f39f21d8 1373
61947107
JH
1374But note that the Thread.pm interface is now shared by both
1375thread models.
f39f21d8 1376
61947107 1377=back
f39f21d8 1378
61947107 1379=head2 New Or Improved Platforms
f39f21d8 1380
61947107
JH
1381For the list of platforms known to support Perl,
1382see L<perlport/"Supported Platforms">.
1383
1384=over 4
f39f21d8
JH
1385
1386=item *
1387
61947107 1388AIX dynamic loading should be now better supported.
f39f21d8 1389
f39f21d8
JH
1390=item *
1391
77c8cf41
JH
1392AIX should now work better with gcc, threads, and 64-bitness. Also the
1393long doubles support in AIX should be better now. See L<perlaix>.
f39f21d8
JH
1394
1395=item *
1396
61947107
JH
1397After a long pause, AmigaOS has been verified to be happy with Perl.
1398
1399=item *
1400
77c8cf41 1401AtheOS (http://www.atheos.cx/) is a new platform.
f39f21d8 1402
77c8cf41 1403=item *
f39f21d8 1404
77c8cf41 1405DG/UX platform now supports the 5.005-style threads. See L<perldgux>.
f39f21d8
JH
1406
1407=item *
1408
77c8cf41 1409DYNIX/ptx platform (a.k.a. dynixptx) is supported at or near osvers 4.5.2.
f39f21d8
JH
1410
1411=item *
1412
61947107
JH
1413EBCDIC platforms (z/OS, also known as OS/390, POSIX-BC, and VM/ESA)
1414have been regained. Many test suite tests still fail and the
1415co-existence of Unicode and EBCDIC isn't quite settled, but the
1416situation is much better than with Perl 5.6. See L<perlos390>,
1417L<perlbs2000> (for POSIX-BC), and L<perlvmesa> for more information.
f39f21d8
JH
1418
1419=item *
1420
61947107
JH
1421Building perl with -Duseithreads or -Duse5005threads now works under
1422HP-UX 10.20 (previously it only worked under 10.30 or later). You will
1423need a thread library package installed. See README.hpux.
f39f21d8 1424
77c8cf41 1425=item *
f39f21d8 1426
61947107
JH
1427MacOS Classic (MacPerl has of course been available since
1428perl 5.004 but now the source code bases of standard Perl
1429and MacPerl have been synchronised)
f39f21d8 1430
77c8cf41 1431=item *
f39f21d8 1432
61947107
JH
1433MacOS X (or Darwin) should now be able to build Perl even on HFS+
1434filesystems. (The case-insensitivity confused the Perl build process.)
f39f21d8 1435
888aee59
JH
1436=item *
1437
61947107 1438NCR MP-RAS is now supported.
888aee59
JH
1439
1440=item *
1441
61947107 1442NetWare from Novell is now supported. See L<perlnetware>.
888aee59
JH
1443
1444=item *
1445
61947107 1446NonStop-UX is now supported.
888aee59
JH
1447
1448=item *
1449
61947107 1450Amdahl UTS UNIX mainframe platform is now supported.
888aee59
JH
1451
1452=item *
1453
61947107
JH
1454WinCE is now supported. See L<perlce>.
1455
1456=item *
1457
1458z/OS (formerly known as OS/390, formerly known as MVS OE) has now
1459support for dynamic loading. This is not selected by default,
1460however, you must specify -Dusedl in the arguments of Configure.
888aee59 1461
f39f21d8
JH
1462=back
1463
1464=head1 Selected Bug Fixes
1465
e1f170bd
JH
1466Numerous memory leaks and uninitialized memory accesses have been
1467hunted down. Most importantly anonymous subs used to leak quite
1468a bit.
ba370e9b 1469
f39f21d8
JH
1470=over 4
1471
1472=item *
1473
e1f170bd 1474The autouse pragma didn't work for Multi::Part::Function::Names.
f39f21d8
JH
1475
1476=item *
1477
e1f170bd
JH
1478chop(@list) in list context returned the characters chopped in
1479reverse order. This has been reversed to be in the right order.
f39f21d8
JH
1480
1481=item *
1482
e1f170bd
JH
1483Configure no longer includes the DBM libraries (dbm, gdbm, db, ndbm)
1484when building the Perl binary. The only exception to this is SunOS 4.x,
1485which needs them.
f39f21d8
JH
1486
1487=item *
1488
e1f170bd
JH
1489The behaviour of non-decimal but numeric string constants such as
1490"0x23" was platform-dependent: in some platforms that was seen as 35,
1491in some as 0, in some as a floating point number (don't ask). This
1492was caused by Perl using the operating system libraries in a situation
1493where the result of the string to number conversion is undefined: now
1494Perl consistently handles such strings as zero in numeric contexts.
f39f21d8
JH
1495
1496=item *
1497
e1f170bd 1498The order of DESTROYs has been made more predictable.
f39f21d8
JH
1499
1500=item *
1501
e1f170bd
JH
1502Several debugger fixes: exit code now reflects the script exit code,
1503condition C<"0"> now treated correctly, the C<d> command now checks
1504line number, the C<$.> no longer gets corrupted, all debugger output now
1505goes correctly to the socket if RemotePort is set.
f39f21d8
JH
1506
1507=item *
1508
e1f170bd 1509L<dprofpp> -R didn't work.
f39f21d8
JH
1510
1511=item *
1512
e1f170bd 1513C<*foo{FORMAT}> now works.
f39f21d8
JH
1514
1515=item *
1516
e1f170bd
JH
1517UNIVERSAL::isa no longer caches methods incorrectly. (This broke
1518the Tk extension with 5.6.0.)
f39f21d8
JH
1519
1520=item *
1521
e1f170bd
JH
1522Lexicals I: lexicals outside an eval "" weren't resolved
1523correctly inside a subroutine definition inside the eval "" if they
1524were not already referenced in the top level of the eval""ed code.
f39f21d8
JH
1525
1526=item *
1527
e1f170bd
JH
1528Lexicals II: lexicals leaked at file scope into subroutines that
1529were declared before the lexicals.
f39f21d8
JH
1530
1531=item *
1532
e1f170bd 1533Lexical warnings now propagating correctly between scopes.
f39f21d8
JH
1534
1535=item *
1536
e1f170bd 1537Line renumbering with eval and C<#line> now works.
f39f21d8
JH
1538
1539=item *
1540
e1f170bd 1541Fixed numerous memory leaks, especially in eval "".
f39f21d8
JH
1542
1543=item *
1544
e1f170bd
JH
1545mkdir() now ignores trailing slashes in the directory name,
1546as mandated by POSIX.
f39f21d8
JH
1547
1548=item *
1549
e1f170bd
JH
1550Some versions of glibc have a broken modfl(). This affects builds
1551with C<-Duselongdouble>. This version of Perl detects this brokenness
1552and has a workaround for it. The glibc release 2.2.2 is known to have
1553fixed the modfl() bug.
f39f21d8
JH
1554
1555=item *
1556
e1f170bd
JH
1557Modulus of unsigned numbers now works (4063328477 % 65535 used to
1558return 27406, instead of 27047).
f39f21d8
JH
1559
1560=item *
1561
e1f170bd
JH
1562Some "not a number" warnings introduced in 5.6.0 eliminated to be
1563more compatible with 5.005. Infinity is now recognised as a number.
f39f21d8 1564
77c8cf41 1565=item *
f39f21d8 1566
e1f170bd 1567Attributes (like :shared) didn't work with our().
f39f21d8
JH
1568
1569=item *
1570
e1f170bd 1571our() variables will not cause "will not stay shared" warnings.
f39f21d8
JH
1572
1573=item *
1574
e1f170bd 1575pack "Z" now correctly terminates the string with "\0".
f39f21d8
JH
1576
1577=item *
1578
e1f170bd
JH
1579Fix password routines which in some shadow password platforms
1580(e.g. HP-UX) caused getpwent() to return every other entry.
f39f21d8 1581
77c8cf41 1582=item *
f39f21d8 1583
e1f170bd
JH
1584The PERL5OPT environment variable (for passing command line arguments
1585to Perl) didn't work for more than a single group of options.
f39f21d8 1586
77c8cf41 1587=item *
f39f21d8 1588
e1f170bd 1589PERL5OPT with embedded spaces didn't work.
f39f21d8 1590
77c8cf41 1591=item *
f39f21d8 1592
e1f170bd 1593printf() no longer resets the numeric locale to "C".
f39f21d8 1594
77c8cf41 1595=item *
f39f21d8 1596
e1f170bd 1597C<q(a\\b)> now parses correctly as C<'a\\b'>.
f39f21d8 1598
77c8cf41 1599=item *
f39f21d8 1600
e1f170bd
JH
1601Printing quads (64-bit integers) with printf/sprintf now works
1602without the q L ll prefixes (assuming you are on a quad-capable platform).
f39f21d8 1603
77c8cf41 1604=item *
f39f21d8 1605
e1f170bd 1606Regular expressions on references and overloaded scalars now work.
f39f21d8 1607
ba370e9b
JH
1608=item *
1609
e1f170bd
JH
1610Right-hand side magic (GMAGIC) could in many cases such as string
1611concatenation be invoked too many times.
ba370e9b
JH
1612
1613=item *
1614
e1f170bd 1615scalar() now forces scalar context even when used in void context.
ba370e9b
JH
1616
1617=item *
1618
e1f170bd 1619SOCKS support is now much more robust.
ba370e9b
JH
1620
1621=item *
1622
e1f170bd
JH
1623sort() arguments are now compiled in the right wantarray context
1624(they were accidentally using the context of the sort() itself).
ba370e9b
JH
1625
1626=item *
1627
e1f170bd 1628Changed the POSIX character class C<[[:space:]]> to include the (very
c2e23569
JH
1629rarely used) vertical tab character. Added a new POSIX-ish character
1630class C<[[:blank:]]> which stands for horizontal whitespace
1631(currently, the space and the tab).
ba370e9b
JH
1632
1633=item *
1634
1635The tainting behaviour of sprintf() has been rationalized. It does
1636not taint the result of floating point formats anymore, making the
1637behaviour consistent with that of string interpolation.
1638
1639=item *
1640
c2e23569
JH
1641The regular expression captured submatches ($1, $2, ...) are now
1642more consistently unset if the match fails, instead of leaving false
1643data lying around in them.
1644
1645=item *
1646
1647C<Sys::Syslog> ignored the C<LOG_AUTH> constant.
ba370e9b
JH
1648
1649=item *
1650
e1f170bd 1651All but the first argument of the IO syswrite() method are now optional.
ba370e9b
JH
1652
1653=item *
1654
e1f170bd
JH
1655$AUTOLOAD, sort(), lock(), and spawning subprocesses
1656in multiple threads simultaneously are now thread-safe.
ba370e9b
JH
1657
1658=item *
1659
e1f170bd 1660Tie::ARRAY SPLICE method was broken.
ba370e9b
JH
1661
1662=item *
1663
e1f170bd 1664Allow read-only string on left hand side of non-modifying tr///.
ba370e9b
JH
1665
1666=item *
1667
e1f170bd 1668Several Unicode fixes.
ba370e9b
JH
1669
1670=over 8
1671
1672=item *
1673
e1f170bd
JH
1674BOMs (byte order marks) in the beginning of Perl files
1675(scripts, modules) should now be transparently skipped.
1676UTF-16 (UCS-2) encoded Perl files should now be read correctly.
ba370e9b
JH
1677
1678=item *
1679
e1f170bd 1680The character tables have been updated to Unicode 3.1.1.
ba370e9b
JH
1681
1682=item *
1683
e1f170bd
JH
1684Comparing with utf8 data does not magically upgrade non-utf8 data
1685into utf8.
ba370e9b
JH
1686
1687=item *
1688
e1f170bd 1689C<IsAlnum>, C<IsAlpha>, and C<IsWord> now match titlecase.
f39f21d8 1690
77c8cf41 1691=item *
f39f21d8 1692
e1f170bd
JH
1693Concatenation with the C<.> operator or via variable interpolation,
1694C<eq>, C<substr>, C<reverse>, C<quotemeta>, the C<x> operator,
1695substitution with C<s///>, single-quoted UTF8, should now work.
f39f21d8 1696
77c8cf41 1697=item *
f39f21d8 1698
e1f170bd
JH
1699The C<tr///> operator now works. Note that the C<tr///CU>
1700functionality has been removed (but see pack('U0', ...)).
f39f21d8 1701
77c8cf41 1702=item *
f39f21d8 1703
e1f170bd 1704C<eval "v200"> now works.
f39f21d8 1705
77c8cf41 1706=item *
f39f21d8 1707
e1f170bd 1708Zero entries were missing from the Unicode classes like C<IsDigit>.
f39f21d8 1709
e1f170bd 1710=back
f39f21d8 1711
77c8cf41 1712=back
f39f21d8 1713
77c8cf41 1714=head2 Platform Specific Changes and Fixes
f39f21d8
JH
1715
1716=over 4
1717
1718=item *
1719
77c8cf41 1720BSDI 4.*
f39f21d8 1721
77c8cf41 1722Perl now works on post-4.0 BSD/OSes.
f39f21d8
JH
1723
1724=item *
1725
77c8cf41 1726All BSDs
f39f21d8 1727
057b7f2b 1728Setting C<$0> now works (as much as possible; see L<perlvar> for details).
f39f21d8
JH
1729
1730=item *
1731
77c8cf41 1732Cygwin
f39f21d8 1733
77c8cf41 1734Numerous updates; currently synchronised with Cygwin 1.1.4.
f39f21d8
JH
1735
1736=item *
1737
e1f170bd
JH
1738Previously DYNIX/ptx had problems in its Configure probe for non-blocking I/O.
1739
1740=item *
1741
77c8cf41 1742EPOC
f39f21d8 1743
77c8cf41 1744EPOC update after Perl 5.6.0. See README.epoc.
f39f21d8
JH
1745
1746=item *
1747
77c8cf41 1748FreeBSD 3.*
f39f21d8 1749
77c8cf41 1750Perl now works on post-3.0 FreeBSDs.
f39f21d8
JH
1751
1752=item *
1753
77c8cf41
JH
1754HP-UX
1755
1756README.hpux updated; C<Configure -Duse64bitall> now almost works.
f39f21d8
JH
1757
1758=item *
1759
77c8cf41 1760IRIX
f39f21d8 1761
77c8cf41
JH
1762Numerous compilation flag and hint enhancements; accidental mixing
1763of 32-bit and 64-bit libraries (a doomed attempt) made much harder.
f39f21d8 1764
77c8cf41 1765=item *
f39f21d8 1766
77c8cf41 1767Linux
f39f21d8 1768
e1f170bd
JH
1769=over 8
1770
1771=item *
1772
77c8cf41 1773Long doubles should now work (see INSTALL).
f39f21d8
JH
1774
1775=item *
1776
e1f170bd
JH
1777Linux previously had problems related to sockaddrlen when using
1778accept(), revcfrom() (in Perl: recv()), getpeername(), and getsockname().
1779
1780=back
1781
1782=item *
1783
77c8cf41 1784MacOS Classic
f39f21d8 1785
77c8cf41
JH
1786Compilation of the standard Perl distribution in MacOS Classic should
1787now work if you have the Metrowerks development environment and
1788the missing Mac-specific toolkit bits. Contact the macperl mailing
1789list for details.
f39f21d8
JH
1790
1791=item *
1792
77c8cf41 1793MPE/iX
f39f21d8 1794
77c8cf41 1795MPE/iX update after Perl 5.6.0. See README.mpeix.
f39f21d8
JH
1796
1797=item *
1798
77c8cf41 1799NetBSD/sparc
f39f21d8 1800
77c8cf41 1801Perl now works on NetBSD/sparc.
f39f21d8
JH
1802
1803=item *
1804
77c8cf41 1805OS/2
f39f21d8 1806
77c8cf41 1807Now works with usethreads (see INSTALL).
f39f21d8
JH
1808
1809=item *
1810
77c8cf41 1811Solaris
f39f21d8 1812
77c8cf41 181364-bitness using the Sun Workshop compiler now works.
f39f21d8
JH
1814
1815=item *
1816
77c8cf41 1817Tru64 (aka Digital UNIX, aka DEC OSF/1)
f39f21d8 1818
77c8cf41
JH
1819The operating system version letter now recorded in $Config{osvers}.
1820Allow compiling with gcc (previously explicitly forbidden). Compiling
1821with gcc still not recommended because buggy code results, even with
1822gcc 2.95.2.
f39f21d8
JH
1823
1824=item *
1825
77c8cf41
JH
1826Unicos
1827
1828Fixed various alignment problems that lead into core dumps either
1829during build or later; no longer dies on math errors at runtime;
1830now using full quad integers (64 bits), previously was using
1831only 46 bit integers for speed.
f39f21d8
JH
1832
1833=item *
1834
77c8cf41
JH
1835VMS
1836
1837chdir() now works better despite a CRT bug; now works with MULTIPLICITY
1838(see INSTALL); now works with Perl's malloc.
f39f21d8
JH
1839
1840=item *
1841
77c8cf41 1842Windows
f39f21d8 1843
77c8cf41 1844=over 8
f39f21d8
JH
1845
1846=item *
1847
77c8cf41 1848accept() no longer leaks memory.
f39f21d8
JH
1849
1850=item *
1851
e1f170bd
JH
1852Borland C++ v5.5 is now a supported compiler that can build Perl.
1853However, the generated binaries continue to be incompatible with those
1854generated by the other supported compilers (GCC and Visual C++).
1855
1856=item *
1857
77c8cf41 1858Better chdir() return value for a non-existent directory.
f39f21d8 1859
77c8cf41 1860=item *
f39f21d8 1861
e1f170bd
JH
1862Duping socket handles with open(F, ">&MYSOCK") now works under Windows 9x.
1863
1864=item *
1865
77c8cf41 1866New %ENV entries now propagate to subprocesses.
f39f21d8
JH
1867
1868=item *
1869
77c8cf41
JH
1870$ENV{LIB} now used to search for libs under Visual C.
1871
1872=item *
1873
e1f170bd
JH
1874Win32::GetCwd() correctly returns C:\ instead of C: when at the drive root.
1875Other bugs in chdir() and Cwd::cwd() have also been fixed.
1876
1877=item *
1878
77c8cf41 1879A failed (pseudo)fork now returns undef and sets errno to EAGAIN.
f39f21d8
JH
1880
1881=item *
1882
e1f170bd
JH
1883HTML files will be installed in c:\perl\html instead of c:\perl\lib\pod\html
1884
1885=item *
1886
1887The makefiles now provide a single switch to bulk-enable all the features
1888enabled in ActiveState ActivePerl (a popular Win32 binary distribution).
1889
1890=item *
1891
77c8cf41 1892Allow REG_EXPAND_SZ keys in the registry.
f39f21d8
JH
1893
1894=item *
1895
77c8cf41 1896Can now send() from all threads, not just the first one.
f39f21d8
JH
1897
1898=item *
1899
77c8cf41 1900Fake signal handling reenabled, bugs and all.
f39f21d8
JH
1901
1902=item *
1903
77c8cf41
JH
1904Less stack reserved per thread so that more threads can run
1905concurrently. (Still 16M per thread.)
f39f21d8
JH
1906
1907=item *
1908
c2e23569 1909C<File::Spec-&gt;tmpdir()> now prefers C:/temp over /tmp
77c8cf41 1910(works better when perl is running as service).
f39f21d8
JH
1911
1912=item *
1913
77c8cf41 1914Better UNC path handling under ithreads.
f39f21d8
JH
1915
1916=item *
1917
77c8cf41 1918wait() and waitpid() now work much better.
f39f21d8
JH
1919
1920=item *
1921
77c8cf41 1922winsock handle leak fixed.
f39f21d8
JH
1923
1924=back
1925
77c8cf41 1926=back
f39f21d8 1927
77c8cf41 1928=head1 New or Changed Diagnostics
f39f21d8 1929
ba370e9b
JH
1930=over 4
1931
1932=item *
1933
77c8cf41
JH
1934All regular expression compilation error messages are now hopefully
1935easier to understand both because the error message now comes before
1936the failed regex and because the point of failure is now clearly
ba370e9b
JH
1937marked by a C<E<lt>-- HERE> marker.
1938
1939=item *
f39f21d8 1940
77c8cf41
JH
1941The various "opened only for", "on closed", "never opened" warnings
1942drop the C<main::> prefix for filehandles in the C<main> package,
bea4d472 1943for example C<STDIN> instead of C<main::STDIN>.
f39f21d8 1944
ba370e9b
JH
1945=item *
1946
77c8cf41
JH
1947The "Unrecognized escape" warning has been extended to include C<\8>,
1948C<\9>, and C<\_>. There is no need to escape any of the C<\w> characters.
f39f21d8 1949
ba370e9b 1950=item *
f39f21d8 1951
77c8cf41
JH
1952Two new debugging options have been added: if you have compiled your
1953Perl with debugging, you can use the -DT and -DR options to trace
1954tokenising and to add reference counts to displaying variables,
1955respectively.
f39f21d8
JH
1956
1957=item *
1958
77c8cf41
JH
1959If an attempt to use a (non-blessed) reference as an array index
1960is made, a warning is given.
f39f21d8
JH
1961
1962=item *
1963
77c8cf41
JH
1964C<push @a;> and C<unshift @a;> (with no values to push or unshift)
1965now give a warning. This may be a problem for generated and evaled
1966code.
f39f21d8 1967
ba370e9b
JH
1968=item *
1969
1970If you try to L<perlfunc/pack> a number less than 0 or larger than 255
1971using the C<"C"> format you will get an optional warning. Similarly
1972for the C<"c"> format and a number less than -128 or more than 127.
1973
1974=item *
1975
1976Certain regex modifiers such as C<(?o)> make sense only if applied to
1977the entire regex. You will an optional warning if you try to do otherwise.
1978
1979=item *
1980
c2e23569
JH
1981Using arrays or hashes as references (e.g. C<< %foo-&gt;{bar} >>
1982has been deprecated for a while. Now you will get an optional warning.
ba370e9b 1983
f39f21d8
JH
1984=back
1985
77c8cf41 1986=head1 Changed Internals
f39f21d8
JH
1987
1988=over 4
1989
1990=item *
1991
77c8cf41
JH
1992perlapi.pod (a companion to perlguts) now attempts to document the
1993internal API.
f39f21d8
JH
1994
1995=item *
1996
77c8cf41
JH
1997You can now build a really minimal perl called microperl.
1998Building microperl does not require even running Configure;
1999C<make -f Makefile.micro> should be enough. Beware: microperl makes
2000many assumptions, some of which may be too bold; the resulting
2001executable may crash or otherwise misbehave in wondrous ways.
2002For careful hackers only.
f39f21d8
JH
2003
2004=item *
2005
c2e23569
JH
2006Added rsignal(), whichsig(), do_join(), op_clear, op_null,
2007ptr_table_clear(), ptr_table_free(), sv_setref_uv(), and several UTF-8
2008interfaces to the publicised API. For the full list of the available
2009APIs see L<perlapi>.
f39f21d8
JH
2010
2011=item *
2012
77c8cf41 2013Made possible to propagate customised exceptions via croak()ing.
f39f21d8 2014
77c8cf41 2015=item *
f39f21d8 2016
77c8cf41 2017Now xsubs can have attributes just like subs.
f39f21d8
JH
2018
2019=item *
2020
77c8cf41
JH
2021dTHR and djSP have been obsoleted; the former removed (because it's
2022a no-op) and the latter replaced with dSP.
f39f21d8
JH
2023
2024=item *
2025
61947107
JH
2026PERL_OBJECT has been completely removed.
2027
2028=item *
2029
ba370e9b
JH
2030The MAGIC constants (e.g. C<'P'>) have been macrofied
2031(e.g. C<PERL_MAGIC_TIED>) for better source code readability
2032and maintainability.
2033
2034=item *
2035
2036The regex compiler now maintains a structure that identifies nodes in
2037the compiled bytecode with the corresponding syntactic features of the
2038original regex expression. The information is attached to the new
2039C<offsets> member of the C<struct regexp>. See L<perldebguts> for more
2040complete information.
2041
2042=item *
2043
2044The C code has been made much more C<gcc -Wall> clean. Some warning
2045messages still remain in some platforms, so if you are compiling with
2046gcc you may see some warnings about dubious practices. The warnings
2047are being worked on.
2048
2049=item *
2050
2051F<perly.c>, F<sv.c>, and F<sv.h> have now been extensively commented.
2052
2053=item *
2054
61947107
JH
2055Documentation on how to use the Perl source repository has been added
2056to F<Porting/repository.pod>.
f39f21d8 2057
888aee59
JH
2058=item *
2059
c2e23569 2060There are now several profiling make targets.
888aee59 2061
77c8cf41 2062=back
f39f21d8 2063
77c8cf41 2064=head1 Security Vulnerability Closed
f39f21d8 2065
77c8cf41 2066(This change was already made in 5.7.0 but bears repeating here.)
f39f21d8 2067
77c8cf41
JH
2068A potential security vulnerability in the optional suidperl component
2069of Perl was identified in August 2000. suidperl is neither built nor
2070installed by default. As of November 2001 the only known vulnerable
2071platform is Linux, most likely all Linux distributions. CERT and
2072various vendors and distributors have been alerted about the vulnerability.
2073See http://www.cpan.org/src/5.0/sperl-2000-08-05/sperl-2000-08-05.txt
2074for more information.
f39f21d8 2075
77c8cf41
JH
2076The problem was caused by Perl trying to report a suspected security
2077exploit attempt using an external program, /bin/mail. On Linux
2078platforms the /bin/mail program had an undocumented feature which
2079when combined with suidperl gave access to a root shell, resulting in
2080a serious compromise instead of reporting the exploit attempt. If you
2081don't have /bin/mail, or if you have 'safe setuid scripts', or if
2082suidperl is not installed, you are safe.
f39f21d8 2083
77c8cf41
JH
2084The exploit attempt reporting feature has been completely removed from
2085Perl 5.8.0 (and the maintenance release 5.6.1, and it was removed also
2086from all the Perl 5.7 releases), so that particular vulnerability
2087isn't there anymore. However, further security vulnerabilities are,
ba370e9b
JH
2088unfortunately, always possible. The suidperl functionality is most
2089probably going to be removed in Perl 5.10. In any case, suidperl
2090should only be used by security experts who know exactly what they are
2091doing and why they are using suidperl instead of some other solution
2092such as sudo (see http://www.courtesan.com/sudo/).
77c8cf41
JH
2093
2094=head1 New Tests
2095
2096Several new tests have been added, especially for the F<lib> subsection.
2097
2098The tests are now reported in a different order than in earlier Perls.
2099(This happens because the test scripts from under t/lib have been moved
2100to be closer to the library/extension they are testing.)
2101
f39f21d8
JH
2102=head1 Known Problems
2103
2104Note that unlike other sections in this document (which describe
2105changes since 5.7.0) this section is cumulative containing known
2106problems for all the 5.7 releases.
2107
2108=head2 AIX
2109
2110=over 4
2111
2112=item *
2113
2114In AIX 4.2 Perl extensions that use C++ functions that use statics
2115may have problems in that the statics are not getting initialized.
2116In newer AIX releases this has been solved by linking Perl with
2117the libC_r library, but unfortunately in AIX 4.2 the said library
2118has an obscure bug where the various functions related to time
2119(such as time() and gettimeofday()) return broken values, and
2120therefore in AIX 4.2 Perl is not linked against the libC_r.
2121
2122=item *
2123
2124vac 5.0.0.0 May Produce Buggy Code For Perl
2125
2126The AIX C compiler vac version 5.0.0.0 may produce buggy code,
2127resulting in few random tests failing, but when the failing tests
2128are run by hand, they succeed. We suggest upgrading to at least
2129vac version 5.0.1.0, that has been known to compile Perl correctly.
2130"lslpp -L|grep vac.C" will tell you the vac version.
2131
2132=back
2133
2134=head2 Amiga Perl Invoking Mystery
2135
2136One cannot call Perl using the C<volume:> syntax, that is, C<perl -v>
057b7f2b 2137works, but for example C<bin:perl -v> doesn't. The exact reason isn't
f39f21d8
JH
2138known but the current suspect is the F<ixemul> library.
2139
2140=head2 lib/ftmp-security tests warn 'system possibly insecure'
2141
2142Don't panic. Read INSTALL 'make test' section instead.
2143
2144=head2 Cygwin intermittent failures of lib/Memoize/t/expire_file 11 and 12
2145
2146The subtests 11 and 12 sometimes fail and sometimes work.
2147
2148=head2 HP-UX lib/io_multihomed Fails When LP64-Configured
2149
2150The lib/io_multihomed test may hang in HP-UX if Perl has been
2151configured to be 64-bit. Because other 64-bit platforms do not hang in
2152this test, HP-UX is suspect. All other tests pass in 64-bit HP-UX. The
2153test attempts to create and connect to "multihomed" sockets (sockets
2154which have multiple IP addresses).
2155
2156=head2 HP-UX lib/posix Subtest 9 Fails When LP64-Configured
2157
2158If perl is configured with -Duse64bitall, the successful result of the
2159subtest 10 of lib/posix may arrive before the successful result of the
2160subtest 9, which confuses the test harness so much that it thinks the
2161subtest 9 failed.
2162
2163=head2 Linux With Sfio Fails op/misc Test 48
2164
2165No known fix.
2166
2167=head2 OS/390
2168
2169OS/390 has rather many test failures but the situation is actually
2170better than it was in 5.6.0, it's just that so many new modules and
2171tests have been added.
2172
2173 Failed Test Stat Wstat Total Fail Failed List of Failed
2174 -----------------------------------------------------------------------------
2175 ../ext/B/Deparse.t 14 1 7.14% 14
2176 ../ext/B/Showlex.t 1 1 100.00% 1
2177 ../ext/Encode/Encode/Tcl.t 610 13 2.13% 592 594 596 598
2178 600 602 604-610
2179 ../ext/IO/lib/IO/t/io_unix.t 113 28928 5 3 60.00% 3-5
2180 ../ext/POSIX/POSIX.t 29 1 3.45% 14
2181 ../ext/Storable/t/lock.t 255 65280 5 3 60.00% 3-5
2182 ../lib/locale.t 129 33024 117 19 16.24% 99-117
2183 ../lib/warnings.t 434 1 0.23% 75
2184 ../lib/ExtUtils.t 27 1 3.70% 25
2185 ../lib/Math/BigInt/t/bigintpm.t 1190 1 0.08% 1145
2186 ../lib/Unicode/UCD.t 81 48 59.26% 1-16 49-64 66-81
2187 ../lib/User/pwent.t 9 1 11.11% 4
2188 op/pat.t 660 6 0.91% 242-243 424-425
2189 626-627
2190 op/split.t 0 9 ?? ?? % ??
2191 op/taint.t 174 3 1.72% 156 162 168
2192 op/tr.t 70 3 4.29% 50 58-59
2193 Failed 16/422 test scripts, 96.21% okay. 105/23251 subtests failed, 99.55% okay.
2194
2195=head2 op/sprintf tests 129 and 130
2196
2197The op/sprintf tests 129 and 130 are known to fail on some platforms.
2198Examples include any platform using sfio, and Compaq/Tandem's NonStop-UX.
2199The failing platforms do not comply with the ANSI C Standard, line
220019ff on page 134 of ANSI X3.159 1989 to be exact. (They produce
2201something other than "1" and "-1" when formatting 0.6 and -0.6 using
2202the printf format "%.0f", most often they produce "0" and "-0".)
2203
2204=head2 Failure of Thread tests
2205
2206B<Note that support for 5.005-style threading remains experimental.>
2207
2208The following tests are known to fail due to fundamental problems in
2209the 5.005 threading implementation. These are not new failures--Perl
22105.005_0x has the same bugs, but didn't have these tests.
2211
2212 lib/autouse.t 4
2213 t/lib/thr5005.t 19-20
2214
2215=head2 UNICOS
2216
2217=over 4
2218
2219=item *
2220
2221ext/POSIX/sigaction subtests 6 and 13 may fail.
2222
2223=item *
2224
2225lib/ExtUtils may spuriously claim that subtest 28 failed,
2226which is interesting since the test only has 27 tests.
2227
2228=item *
2229
2230Numerous numerical test failures
2231
2232 op/numconvert 209,210,217,218
2233 op/override 7
2234 ext/Time/HiRes/HiRes 9
2235 lib/Math/BigInt/t/bigintpm 1145
2236 lib/Math/Trig 25
2237
2238These tests fail because of yet unresolved floating point inaccuracies.
2239
2240=back
2241
2242=head2 UTS
2243
2244There are a few known test failures, see L<perluts>.
2245
2246=head2 VMS
2247
057b7f2b
SG
2248Rather a lot of tests are failing in VMS, but actually more tests
2249succeed in VMS than they used to; it's just that there are many,
f39f21d8
JH
2250many more tests than there used to be.
2251
2252Here are the known failures from some compiler/platform combinations.
2253
aecce728
JH
2254Compaq C V6.2-009 on OpenVMS Alpha V7.3
2255
2256 [.run]switches..........................FAILED on test 1
2257 [-.ext.posix.t]posix....................FAILED on test 10
2258 [-.ext.time.hires]hires.................FAILED on test 17
2259 [-.lib]db...............................FAILED on test 24
2260 [-.lib.net]hostent......................FAILED on test 5
2261 [-.lib.pod.t]basic......................FAILED on test 10
2262
f39f21d8
JH
2263=head2 Win32
2264
2265In multi-CPU boxes there are some problems with the I/O buffering:
2266some output may appear twice.
2267
2268=head2 Localising a Tied Variable Leaks Memory
2269
2270 use Tie::Hash;
2271 tie my %tie_hash => 'Tie::StdHash';
2272
2273 ...
2274
2275 local($tie_hash{Foo}) = 1; # leaks
2276
2277Code like the above is known to leak memory every time the local()
2278is executed.
2279
aecce728
JH
2280=head2 Localising Tied Arrays and Hashes Is Broken
2281
2282 local %tied_array;
2283
2284doesn't work as one would expect: the old value is restored
2285incorrectly.
2286
f39f21d8
JH
2287=head2 Self-tying of Arrays and Hashes Is Forbidden
2288
2289Self-tying of arrays and hashes is broken in rather deep and
2290hard-to-fix ways. As a stop-gap measure to avoid people from getting
2291frustrated at the mysterious results (core dumps, most often) it is
2292for now forbidden (you will get a fatal error even from an attempt).
2293
2294=head2 Variable Attributes are not Currently Usable for Tieing
2295
2296This limitation will hopefully be fixed in future. (Subroutine
2297attributes work fine for tieing, see L<Attribute::Handlers>).
2298
aecce728
JH
2299One way to run into this limitation is to have a loop variable with
2300attributes within a loop: the tie is called only once, not for each
2301iteration of the loop.
2302
f39f21d8
JH
2303=head2 Building Extensions Can Fail Because Of Largefiles
2304
2305Some extensions like mod_perl are known to have issues with
2306`largefiles', a change brought by Perl 5.6.0 in which file offsets
2307default to 64 bits wide, where supported. Modules may fail to compile
2308at all or compile and work incorrectly. Currently there is no good
2309solution for the problem, but Configure now provides appropriate
2310non-largefile ccflags, ldflags, libswanted, and libs in the %Config
2311hash (e.g., $Config{ccflags_nolargefiles}) so the extensions that are
2312having problems can try configuring themselves without the
2313largefileness. This is admittedly not a clean solution, and the
2314solution may not even work at all. One potential failure is whether
2315one can (or, if one can, whether it's a good idea) link together at
2316all binaries with different ideas about file offsets, all this is
2317platform-dependent.
2318
aecce728
JH
2319=head2 Unicode Support on EBCDIC Still Spotty
2320
2321Though mostly working, Unicode support still has problem spots on
2322EBCDIC platforms. One such known spot are the C<\p{}> and C<\P{}>
2323regular expression constructs for code points less than 256: the
2324pP are testing for Unicode code points, not knowing about EBCDIC.
2325
f39f21d8
JH
2326=head2 The Compiler Suite Is Still Experimental
2327
2328The compiler suite is slowly getting better but is nowhere near
2329working order yet.
2330
2331=head2 The Long Double Support is Still Experimental
2332
2333The ability to configure Perl's numbers to use "long doubles",
2334floating point numbers of hopefully better accuracy, is still
2335experimental. The implementations of long doubles are not yet
2336widespread and the existing implementations are not quite mature
2337or standardised, therefore trying to support them is a rare
2338and moving target. The gain of more precision may also be offset
2339by slowdown in computations (more bits to move around, and the
2340operations are more likely to be executed by less optimised
2341libraries).
33a87e58 2342
cc0fca54
GS
2343=head1 Reporting Bugs
2344
d4ad863d
JH
2345If you find what you think is a bug, you might check the articles
2346recently posted to the comp.lang.perl.misc newsgroup and the perl
2347bug database at http://bugs.perl.org. There may also be
2348information at http://www.perl.com/perl/, the Perl Home Page.
cc0fca54
GS
2349
2350If you believe you have an unreported bug, please run the B<perlbug>
2351program included with your release. Be sure to trim your bug down
2352to a tiny but sufficient test case. Your bug report, along with the
d4ad863d 2353output of C<perl -V>, will be sent off to perlbug@perl.org to be
cc0fca54
GS
2354analysed by the Perl porting team.
2355
2356=head1 SEE ALSO
2357
2358The F<Changes> file for exhaustive details on what changed.
2359
2360The F<INSTALL> file for how to build Perl.
2361
2362The F<README> file for general stuff.
2363
2364The F<Artistic> and F<Copying> files for copyright information.
2365
2366=head1 HISTORY
2367
d468ca04 2368Written by Jarkko Hietaniemi <F<jhi@iki.fi>>.
cc0fca54
GS
2369
2370=cut