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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 New Unicode Properties
92
93Unicode I<scripts> are now supported. Scripts are similar to (and superior
94to) Unicode I<blocks>. The difference between scripts and blocks is that
95scripts are the glyphs used by a language or a group of languages, while
96the blocks are more artificial groupings of (mostly) 256 characters based
97on the Unicode numbering.
98
99In general, scripts are more inclusive, but not universally so. For
100example, while the script C<Latin> includes all the Latin characters and
101their various diacritic-adorned versions, it does not include the various
102punctuation or digits (since they are not solely C<Latin>).
103
104A number of other properties are now supported, including C<\p{L&}>,
105C<\p{Any}> C<\p{Assigned}>, C<\p{Unassigned}>, C<\p{Blank}> and
106C<\p{SpacePerl}> (along with their C<\P{...}> versions, of course).
107See L<perlunicode> for details, and more additions.
108
109The C<In> or C<Is> prefix to names used with the C<\p{...}> and C<\P{...}>
110are now almost always optional. The only exception is that a C<In> prefix
111is required to signify a Unicode block when a block name conflicts with a
112script name. For example, C<\p{Tibetan}> refers to the script, while
113C<\p{InTibetan}> refers to the block. When there is no name conflict, you
114can omit the C<In> from the block name (e.g. C<\p{BraillePatterns}>), but
115to be safe, it's probably best to always use the C<In>).
77c8cf41 116
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117=head2 Perl Parser Stress Tested
118
119The Perl parser has been stress tested using both random input and
120Markov chain input and the few found crashes and lockups have been
121fixed.
122
c2e23569 123=head2 REF(...) Instead Of SCALAR(...)
77c8cf41 124
057b7f2b 125A reference to a reference now stringifies as "REF(0x81485ec)" instead
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126of "SCALAR(0x81485ec)" in order to be more consistent with the return
127value of ref().
77c8cf41 128
c2e23569 129=head2 Deprecations
77c8cf41 130
61947107 131=over 4
77c8cf41 132
61947107 133=item *
f39f21d8 134
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135The semantics of bless(REF, REF) were unclear and until someone proves
136it to make some sense, it is forbidden.
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137
138=item *
139
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140The obsolete chat2 library that should never have been allowed
141to escape the laboratory has been decommissioned.
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142
143=item *
144
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145The builtin dump() function has probably outlived most of its
146usefulness. The core-dumping functionality will remain in future
147available as an explicit call to C<CORE::dump()>, but in future
148releases the behaviour of an unqualified C<dump()> call may change.
149
150=item *
151
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152The very dusty examples in the eg/ directory have been removed.
153Suggestions for new shiny examples welcome but the main issue is that
154the examples need to be documented, tested and (most importantly)
155maintained.
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156
157=item *
158
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159The (bogus) escape sequences \8 and \9 now give an optional warning
160("Unrecognized escape passed through"). There is no need to \-escape
161any C<\w> character.
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162
163=item *
164
c2e23569 165The list of filenames from glob() (or <...>) is now by default sorted
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166alphabetically to be csh-compliant (which is what happened before
167in most UNIX platforms). (bsd_glob() does still sort platform
c2e23569 168natively, ASCII or EBCDIC, unless GLOB_ALPHASORT is specified.)
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169
170=item *
171
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172Spurious syntax errors generated in certain situations, when glob()
173caused File::Glob to be loaded for the first time, have been fixed.
174
175=item *
176
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177Although "you shouldn't do that", it was possible to write code that
178depends on Perl's hashed key order (Data::Dumper does this). The new
179algorithm "One-at-a-Time" produces a different hashed key order.
180More details are in L</"Performance Enhancements">.
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181
182=item *
183
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184lstat(FILEHANDLE) now gives a warning because the operation makes no sense.
185In future releases this may become a fatal error.
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186
187=item *
188
057b7f2b 189The C<package;> syntax (C<package> without an argument) has been
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190deprecated. Its semantics were never that clear and its
191implementation even less so. If you have used that feature to
192disallow all but fully qualified variables, C<use strict;> instead.
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193
194=item *
195
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196The unimplemented POSIX regex features [[.cc.]] and [[=c=]] are still
197recognised but now cause fatal errors. The previous behaviour of
198ignoring them by default and warning if requested was unacceptable
199since it, in a way, falsely promised that the features could be used.
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200
201=item *
202
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203The current user-visible implementation of pseudo-hashes (the weird
204use of the first array element) is deprecated starting from Perl 5.8.0
205and will be removed in Perl 5.10.0, and the feature will be
206implemented differently. Not only is the current interface rather
207ugly, but the current implementation slows down normal array and hash
208use quite noticeably. The C<fields> pragma interface will remain
209available.
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210
211=item *
212
aecce728 213The syntaxes C<< @a->[...] >> and C<< %h->{...} >> have now been deprecated.
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214
215=item *
216
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217After years of trying the suidperl is considered to be too complex to
218ever be considered truly secure. The suidperl functionality is likely
219to be removed in a future release.
220
221=item *
222
223The long deprecated uppercase aliases for the string comparison
224operators (EQ, NE, LT, LE, GE, GT) have now been removed.
225
226=item *
227
228The tr///C and tr///U features have been removed and will not return;
229the interface was a mistake. Sorry about that. For similar
230functionality, see pack('U0', ...) and pack('C0', ...).
f39f21d8 231
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232=item *
233
234Earlier Perls treated "sub foo (@bar)" as equivalent to "sub foo (@)".
235The prototypes are now checked at compile-time for invalid characters.
236An optional warning is generated ("Illegal character in prototype...")
237but this may be upgraded to a fatal error in a future release.
238
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239=back
240
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241=head1 Core Enhancements
242
77c8cf41 243=head2 PerlIO is Now The Default
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244
245=over 4
246
247=item *
248
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249IO is now by default done via PerlIO rather than system's "stdio".
250PerlIO allows "layers" to be "pushed" onto a file handle to alter the
251handle's behaviour. Layers can be specified at open time via 3-arg
252form of open:
f39f21d8 253
77c8cf41 254 open($fh,'>:crlf :utf8', $path) || ...
f39f21d8 255
77c8cf41 256or on already opened handles via extended C<binmode>:
f39f21d8 257
77c8cf41 258 binmode($fh,':encoding(iso-8859-7)');
f39f21d8 259
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260The built-in layers are: unix (low level read/write), stdio (as in
261previous Perls), perlio (re-implementation of stdio buffering in a
262portable manner), crlf (does CRLF <=> "\n" translation as on Win32,
263but available on any platform). A mmap layer may be available if
264platform supports it (mostly UNIXes).
f39f21d8 265
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266Layers to be applied by default may be specified via the 'open' pragma.
267
268See L</"Installation and Configuration Improvements"> for the effects
269of PerlIO on your architecture name.
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270
271=item *
272
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273File handles can be marked as accepting Perl's internal encoding of Unicode
274(UTF-8 or UTF-EBCDIC depending on platform) by a pseudo layer ":utf8" :
f39f21d8 275
77c8cf41 276 open($fh,">:utf8","Uni.txt");
f39f21d8 277
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278Note for EBCDIC users: the pseudo layer ":utf8" is erroneously named
279for you since it's not UTF-8 what you will be getting but instead
280UTF-EBCDIC. See L<perlunicode>, L<utf8>, and
281http://www.unicode.org/unicode/reports/tr16/ for more information.
282In future releases this naming may change.
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283
284=item *
285
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286File handles can translate character encodings from/to Perl's internal
287Unicode form on read/write via the ":encoding()" layer.
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288
289=item *
290
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291File handles can be opened to "in memory" files held in Perl scalars via:
292
293 open($fh,'>', \$variable) || ...
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294
295=item *
296
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297Anonymous temporary files are available without need to
298'use FileHandle' or other module via
f39f21d8 299
77c8cf41 300 open($fh,"+>", undef) || ...
f39f21d8 301
77c8cf41 302That is a literal undef, not an undefined value.
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303
304=item *
305
77c8cf41 306The list form of C<open> is now implemented for pipes (at least on UNIX):
f39f21d8 307
77c8cf41 308 open($fh,"-|", 'cat', '/etc/motd')
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310creates a pipe, and runs the equivalent of exec('cat', '/etc/motd') in
311the child process.
f39f21d8 312
e1f170bd 313=back
f39f21d8 314
3e33716f 315=head2 Safe Signals
f39f21d8 316
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317Perl used to be fragile in that signals arriving at inopportune moments
318could corrupt Perl's internal state. Now Perl postpones handling of
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319signals until it's safe (between opcodes).
320
56e5bb57 321This change may have surprising side effects because signals no longer
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322interrupt Perl instantly. Perl will now first finish whatever it was
323doing, like finishing an internal operation (like sort()) or an
324external operation (like an I/O operation), and only then look at any
325arrived signals (and before starting the next operation). No more corrupt
326internal state since the current operation is always finished first,
327but the signal may take more time to get heard.
f39f21d8 328
e1f170bd 329=head2 Unicode Overhaul
f39f21d8 330
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331Unicode in general should be now much more usable than in Perl 5.6.0
332(or even in 5.6.1). Unicode can be used in hash keys, Unicode in
333regular expressions should work now, Unicode in tr/// should work now,
334Unicode in I/O should work now.
f39f21d8 335
e1f170bd 336=over 4
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337
338=item *
339
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340The Unicode Character Database coming with Perl has been upgraded
341to Unicode 3.1.1. For more information, see http://www.unicode.org/.
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342
343=item *
344
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345For developers interested in enhancing Perl's Unicode capabilities:
346almost all the UCD files are included with the Perl distribution in
58175c9b 347the F<lib/unicore subdirectory>. The most notable omission, for space
77c8cf41 348considerations, is the Unihan database.
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349
350=item *
351
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352The properties \p{Blank} and \p{SpacePerl} have been added. "Blank" is like
353C isblank(), that is, it contains only "horizontal whitespace" (the space
354character is, the newline isn't), and the "SpacePerl" is the Unicode
355equivalent of C<\s> (\p{Space} isn't, since that includes the vertical
356tabulator character, whereas C<\s> doesn't.)
357
358See "New Unicode Properties" earlier in this document for additional
359information on changes with Unicode properties.
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360
361=back
362
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363=head2 Understanding of Numbers
364
365In general a lot of fixing has happened in the area of Perl's
366understanding of numbers, both integer and floating point. Since in
367many systems the standard number parsing functions like C<strtoul()>
368and C<atof()> seem to have bugs, Perl tries to work around their
369deficiencies. This results hopefully in more accurate numbers.
f39f21d8 370
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371Perl now tries internally to use integer values in numeric conversions
372and basic arithmetics (+ - * /) if the arguments are integers, and
373tries also to keep the results stored internally as integers.
057b7f2b 374This change leads to often slightly faster and always less lossy
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375arithmetics. (Previously Perl always preferred floating point numbers
376in its math.)
377
58175c9b 378=head2 Miscellaneous Changes
e1f170bd 379
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380=over 4
381
382=item *
383
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384AUTOLOAD is now lvaluable, meaning that you can add the :lvalue attribute
385to AUTOLOAD subroutines and you can assign to the AUTOLOAD return value.
386
387=item *
388
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389C<perl -d:Module=arg,arg,arg> now works (previously one couldn't pass
390in multiple arguments.)
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391
392=item *
393
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394The builtin dump() now gives an optional warning
395C<Ambiguous call resolved as CORE::dump(), qualify as such or use &>
396meaning that by default C<dump(...)> is resolved as the builtin
397dump() which dumps core and aborts, not as (possibly) user-defined
398C<sub dump>. To call the latter, qualify the call as C<&dump(...)>.
399(The whole dump() feature is to considered deprecated, and possibly
400removed/changed in future releases.)
401
402=item *
403
404chomp() and chop() have been demoted back to I<not> being overrideable
405because they cannot really be overridden-- the problem is that their
406prototype cannot be expressed and therefore one really cannot write
407replacements to override these builtins.
408
409=item *
410
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411END blocks are now run even if you exit/die in a BEGIN block.
412Internally, the execution of END blocks is now controlled by
413PL_exit_flags & PERL_EXIT_DESTRUCT_END. This enables the new
414behaviour for Perl embedders. This will default in 5.10. See
415L<perlembed>.
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416
417=item *
418
e1f170bd 419Formats now support zero-padded decimal fields.
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420
421=item *
422
77c8cf41 423Lvalue subroutines can now return C<undef> in list context.
44da0e71 424However, the lvalue subroutine feature still remains experimental.
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425
426=item *
427
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428A lost warning "Can't declare ... dereference in my" has been
429restored (Perl had it earlier but it became lost in later releases.)
430
431=item *
432
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433A new special regular expression variable has been introduced:
434C<$^N>, which contains the most-recently closed group (submatch).
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435
436=item *
437
61947107 438C<no Module;> now works even if there is no "sub unimport" in the Module.
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439
440=item *
441
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442The numerical comparison operators return C<undef> if either operand
443is a NaN. Previously the behaviour was unspecified.
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444
445=item *
446
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447The following builtin functions are now overridable: each(), keys(),
448pop(), push(), shift(), splice(), unshift().
449
450=item *
451
61947107 452C<pack('U0a*', ...)> can now be used to force a string to UTF8.
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453
454=item *
455
61947107 456my __PACKAGE__ $obj now works.
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457
458=item *
459
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460The printf() and sprintf() now support parameter reordering using the
461C<%\d+\$> and C<*\d+\$> syntaxes. For example
462
463 print "%2\$s %1\$s\n", "foo", "bar";
464
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465will print "bar foo\n". This feature helps in writing
466internationalised software, and in general when the order
467of the parameters can vary.
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468
469=item *
470
e1f170bd 471prototype(\&) is now available.
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472
473=item *
474
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475prototype(\[$@%&]) is now available to implicitly create references
476(useful for example if you want to emulate the tie() interface).
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477
478=item *
479
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480A new command-line option, C<-t> is available. It is the
481little brother of C<-T>: instead of dieing on taint violations,
482lexical warnings are given. B<This is only meant as a temporary
483debugging aid while securing the code of old legacy applications.
484This is not a substitute for -T.>
485
486=item *
487
488If tr/// is just counting characters, it doesn't attempt to
489modify its target.
490
491=item *
492
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493untie() will now call an UNTIE() hook if it exists. See L<perltie>
494for details.
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495
496=item *
497
498L<utime> now supports C<utime undef, undef, @files> to change the
499file timestamps to the current time.
500
501=item *
502
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503The rules for allowing underscores (underbars) in numeric constants
504have been relaxed and simplified: now you can have an underscore
505simply B<between digits>.
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506
507=back
508
77c8cf41 509=head1 Modules and Pragmata
f39f21d8 510
1e13d81f 511=head2 New Modules and Pragmata
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512
513=over 4
514
515=item *
516
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517C<Attribute::Handlers> allows a class to define attribute handlers.
518
519 package MyPack;
520 use Attribute::Handlers;
521 sub Wolf :ATTR(SCALAR) { print "howl!\n" }
522
523 # later, in some package using or inheriting from MyPack...
524
525 my MyPack $Fluffy : Wolf; # the attribute handler Wolf will be called
526
527Both variables and routines can have attribute handlers. Handlers can
528be specific to type (SCALAR, ARRAY, HASH, or CODE), or specific to the
529exact compilation phase (BEGIN, CHECK, INIT, or END).
530
531=item *
532
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533B<B::Concise> is a new compiler backend for walking the Perl syntax
534tree, printing concise info about ops, from Stephen McCamant. The
535output is highly customisable. See L<B::Concise>.
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536
537=item *
538
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539C<Class::ISA> for reporting the search path for a class's ISA tree,
540by Sean Burke, has been added. See L<Class::ISA>.
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541
542=item *
543
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544C<Cwd> has now a split personality: if possible, an XS extension is
545used, (this will hopefully be faster, more secure, and more robust)
546but if not possible, the familiar Perl implementation is used.
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547
548=item *
549
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550C<Devel::PPPort>, originally from Kenneth Albanowski and now
551maintained by Paul Marquess, has been added. It is primarily used
552by C<h2xs> to enhance portability of of XS modules between different
553versions of Perl.
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554
555=item *
556
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557C<Digest>, frontend module for calculating digests (checksums), from
558Gisle Aas, has been added. See L<Digest>.
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559
560=item *
561
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562C<Digest::MD5> for calculating MD5 digests (checksums) as defined in
563RFC 1321, from Gisle Aas, has been added. See L<Digest::MD5>.
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564
565 use Digest::MD5 'md5_hex';
566
567 $digest = md5_hex("Thirsty Camel");
568
569 print $digest, "\n"; # 01d19d9d2045e005c3f1b80e8b164de1
570
61947107 571NOTE: the C<MD5> backward compatibility module is deliberately not
e1f170bd 572included since its further use is discouraged.
f39f21d8 573
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574=item *
575
61947107 576C<Encode>, by Nick Ing-Simmons, provides a mechanism to translate
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577between different character encodings. Support for Unicode,
578ISO-8859-*, ASCII, CP*, KOI8-R, and three variants of EBCDIC are
579compiled in to the module. Several other encodings (like Japanese,
580Chinese, and MacIntosh encodings) are included and will be loaded at
61947107 581runtime. See L<Encode>.
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582
583Any encoding supported by Encode module is also available to the
584":encoding()" layer if PerlIO is used.
585
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586=item *
587
588C<I18N::Langinfo> can be use to query locale information.
589See L<I18N::Langinfo>.
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590
591=item *
592
61947107 593C<I18N::LangTags> has functions for dealing with RFC3066-style
bea4d472 594language tags, by Sean Burke. See L<I18N::LangTags>.
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595
596=item *
597
598C<ExtUtils::Constant> is a new tool for extension writers for
599generating XS code to import C header constants, by Nicholas Clark.
600See L<ExtUtils::Constant>.
601
602=item *
603
604C<Filter::Simple> is an easy-to-use frontend to Filter::Util::Call,
605from Damian Conway. See L<Filter::Simple>.
f39f21d8
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606
607 # in MyFilter.pm:
608
609 package MyFilter;
610
611 use Filter::Simple sub {
612 while (my ($from, $to) = splice @_, 0, 2) {
613 s/$from/$to/g;
614 }
615 };
616
617 1;
618
619 # in user's code:
620
621 use MyFilter qr/red/ => 'green';
622
623 print "red\n"; # this code is filtered, will print "green\n"
624 print "bored\n"; # this code is filtered, will print "bogreen\n"
625
626 no MyFilter;
627
628 print "red\n"; # this code is not filtered, will print "red\n"
629
61947107
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630=item *
631
632C<File::Temp> allows one to create temporary files and directories in
633an easy, portable, and secure way, by Tim Jenness. See L<File::Temp>.
634
635=item *
636
637C<Filter::Util::Call> provides you with the framework to write
638I<Source Filters> in Perl, from Paul Marquess. For most uses the
639frontend Filter::Simple is to be preferred. See L<Filter::Util::Call>.
640
641=item *
642
643L<libnet> is a collection of perl5 modules related to network
644programming, from Graham Barr. See L<Net::FTP>, L<Net::NNTP>,
645L<Net::Ping>, L<Net::POP3>, L<Net::SMTP>, and L<Net::Time>.
646
647Perl installation leaves libnet unconfigured, use F<libnetcfg> to configure.
f39f21d8
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648
649=item *
650
61947107 651C<List::Util> is a selection of general-utility list subroutines, like
bea4d472 652sum(), min(), first(), and shuffle(), by Graham Barr. See L<List::Util>.
f39f21d8
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653
654=item *
655
61947107
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656C<Locale::Constants>, C<Locale::Country>, C<Locale::Currency>, and
657C<Locale::Language>, from Neil Bowers, have been added. They provide the
658codes for various locale standards, such as "fr" for France, "usd" for
659US Dollar, and "jp" for Japanese.
f39f21d8
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660
661 use Locale::Country;
662
663 $country = code2country('jp'); # $country gets 'Japan'
664 $code = country2code('Norway'); # $code gets 'no'
665
666See L<Locale::Constants>, L<Locale::Country>, L<Locale::Currency>,
61947107
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667and L<Locale::Language>.
668
669=item *
670
671C<Locale::Maketext> is localization framework from Sean Burke. See
672L<Locale::Maketext>, and L<Locale::Maketext::TPJ13>. The latter is an
673article about software localization, originally published in The Perl
674Journal #13, republished here with kind permission.
675
676=item *
677
678C<Memoize> can make your functions faster by trading space for time,
679from Mark-Jason Dominus. See L<Memoize>.
f39f21d8
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680
681=item *
682
61947107
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683C<MIME::Base64> allows you to encode data in base64, from Gisle Aas,
684as defined in RFC 2045 - I<MIME (Multipurpose Internet Mail
685Extensions)>.
f39f21d8
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686
687 use MIME::Base64;
688
689 $encoded = encode_base64('Aladdin:open sesame');
690 $decoded = decode_base64($encoded);
691
692 print $encoded, "\n"; # "QWxhZGRpbjpvcGVuIHNlc2FtZQ=="
693
61947107 694See L<MIME::Base64>.
f39f21d8
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695
696=item *
697
61947107
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698C<MIME::QuotedPrint> allows you to encode data in quoted-printable
699encoding, as defined in RFC 2045 - I<MIME (Multipurpose Internet Mail
700Extensions)>, from Gisle Aas.
f39f21d8
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701
702 use MIME::QuotedPrint;
703
704 $encoded = encode_qp("Smiley in Unicode: \x{263a}");
705 $decoded = decode_qp($encoded);
706
707 print $encoded, "\n"; # "Smiley in Unicode: =263A"
708
709MIME::QuotedPrint has been enhanced to provide the basic methods
710necessary to use it with PerlIO::Via as in :
711
712 use MIME::QuotedPrint;
057b7f2b 713 open($fh,">Via(MIME::QuotedPrint)",$path);
f39f21d8 714
61947107 715See L<MIME::QuotedPrint>.
f39f21d8
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716
717=item *
718
61947107
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719C<NEXT> is pseudo-class for method redispatch, from Damian Conway.
720See L<NEXT>.
f39f21d8
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721
722=item *
723
1e13d81f
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724C<open> is a new pragma for setting the default I/O disciplines
725for open().
726
727=item *
728
61947107
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729C<PerlIO::Scalar> provides the implementation of IO to "in memory"
730Perl scalars as discussed above, from Nick Ing-Simmons. It also
731serves as an example of a loadable PerlIO layer. Other future
732possibilities include PerlIO::Array and PerlIO::Code.
733See L<PerlIO::Scalar>.
734
735=item *
736
737C<PerlIO::Via> acts as a PerlIO layer and wraps PerlIO layer
738functionality provided by a class (typically implemented in perl
739code), from Nick Ing-Simmons.
f39f21d8
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740
741 use MIME::QuotedPrint;
057b7f2b 742 open($fh,">Via(MIME::QuotedPrint)",$path);
f39f21d8
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743
744This will automatically convert everything output to C<$fh>
61947107 745to Quoted-Printable. See L<PerlIO::Via>.
f39f21d8
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746
747=item *
748
1e13d81f 749C<Pod::ParseLink>, by Russ Allbery, has been added,
95f0a2f1 750to parse LZ<><> links in pods as described in the new
1e13d81f
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751perlpodspec.
752
753=item *
754
61947107 755C<Pod::Text::Overstrike>, by Joe Smith, has been added.
f39f21d8 756It converts POD data to formatted overstrike text.
61947107 757See L<Pod::Text::Overstrike>.
f39f21d8
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758
759=item *
760
61947107
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761C<Scalar::Util> is a selection of general-utility scalar subroutines,
762like blessed(), reftype(), and tainted(). See L<Scalar::Util>.
763
764=item *
765
1e13d81f
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766C<sort> is a new pragma for controlling the behaviour of sort().
767
768=item *
769
61947107
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770C<Storable> gives persistence to Perl data structures by allowing the
771storage and retrieval of Perl data to and from files in a fast and
772compact binary format, from Raphael Manfredi. See L<Storable>.
773
774=item *
775
776C<Switch>, from Damian Conway, has been added. Just by saying
f39f21d8
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777
778 use Switch;
779
780you have C<switch> and C<case> available in Perl.
781
782 use Switch;
783
784 switch ($val) {
785
786 case 1 { print "number 1" }
787 case "a" { print "string a" }
788 case [1..10,42] { print "number in list" }
789 case (@array) { print "number in list" }
790 case /\w+/ { print "pattern" }
791 case qr/\w+/ { print "pattern" }
792 case (%hash) { print "entry in hash" }
793 case (\%hash) { print "entry in hash" }
794 case (\&sub) { print "arg to subroutine" }
795 else { print "previous case not true" }
796 }
797
61947107
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798See L<Switch>.
799
800=item *
801
802C<Test::More> is yet another framework for writing test scripts,
803more extensive than Test::Simple, by Michael Schwern. See L<Test::More>.
804
805=item *
806
aecce728 807C<Test::Simple> has basic utilities for writing tests, by Michael
61947107 808Schwern. See L<Test::Simple>.
77c8cf41
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809
810=item *
811
61947107
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812C<Text::Balanced> has been added, for extracting delimited text
813sequences from strings, from Damian Conway.
77c8cf41
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814
815 use Text::Balanced 'extract_delimited';
816
817 ($a, $b) = extract_delimited("'never say never', he never said", "'", '');
818
819$a will be "'never say never'", $b will be ', he never said'.
820
821In addition to extract_delimited() there are also extract_bracketed(),
822extract_quotelike(), extract_codeblock(), extract_variable(),
823extract_tagged(), extract_multiple(), gen_delimited_pat(), and
824gen_extract_tagged(). With these you can implement rather advanced
61947107 825parsing algorithms. See L<Text::Balanced>.
77c8cf41
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826
827=item *
828
c2e23569 829C<threads> is an interface to interpreter threads, by Arthur Bergman.
61947107 830Interpreter threads (ithreads) is the new thread model introduced in
c2e23569
JH
831Perl 5.6 but only available as an internal interface for extension
832writers (and for Win32 Perl for C<fork()> emulation). See L<threads>.
77c8cf41
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833
834=item *
835
61947107
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836C<threads::shared> allows data sharing for interpreter threads, from
837Arthur Bergman. In the ithreads model any data sharing between
838threads must be explicit, as opposed to the old 5.005 thread model
839where data sharing was implicit. See L<threads::shared>.
77c8cf41
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840
841=item *
842
61947107 843C<Tie::RefHash::Nestable>, by Edward Avis, allows storing hash
ba370e9b
JH
844references (unlike the standard Tie::RefHash) The module is contained
845within Tie::RefHash, see L<Tie::RefHash>.
77c8cf41
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846
847=item *
848
61947107
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849C<Time::HiRes> provides high resolution timing (ualarm, usleep,
850and gettimeofday), from Douglas E. Wegscheid. See L<Time::HiRes>.
77c8cf41
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851
852=item *
853
61947107
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854C<Unicode::UCD> offers a querying interface to the Unicode Character
855Database. See L<Unicode::UCD>.
77c8cf41
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856
857=item *
858
61947107
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859C<Unicode::Collate> implements the UCA (Unicode Collation Algorithm)
860for sorting Unicode strings, by SADAHIRO Tomoyuki. See L<Unicode::Collate>.
77c8cf41
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861
862=item *
863
61947107
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864C<Unicode::Normalize> implements the various Unicode normalization
865forms, by SADAHIRO Tomoyuki. See L<Unicode::Normalize>.
77c8cf41
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866
867=item *
868
61947107
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869C<XS::Typemap>, by Tim Jenness, is a test extension that exercises XS
870typemaps. Nothing gets installed but for extension writers the code
871is worth studying.
77c8cf41
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872
873=back
874
875=head2 Updated And Improved Modules and Pragmata
876
877=over 4
878
879=item *
880
61947107
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881The following independently supported modules have been updated to the
882newest versions from CPAN: CGI, CPAN, DB_File, File::Spec, File::Temp,
883Getopt::Long, Math::BigFloat, Math::BigInt, the podlators bundle
884(Pod::Man, Pod::Text), Pod::LaTeX, Pod::Parser, Storable,
885Term::ANSIColor, Test, Text-Tabs+Wrap.
77c8cf41
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886
887=item *
888
61947107 889The attributes::reftype() now works on tied arguments.
77c8cf41
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890
891=item *
892
057b7f2b 893AutoLoader can now be disabled with C<no AutoLoader;>.
77c8cf41
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894
895=item *
896
1e13d81f
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897B::Deparse has been significantly enhanced. It now can deparse almost
898all of the standard test suite (so that the tests still succeed).
899There is a make target "test.deparse" for trying this out.
77c8cf41
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900
901=item *
902
1e13d81f 903Class::Struct can now define the classes in compile time.
77c8cf41
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904
905=item *
906
1e13d81f
JH
907Class::Struct now assigns the array/hash element if the accessor
908is called with an array/hash element as the B<sole> argument.
77c8cf41
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909
910=item *
911
1e13d81f 912Data::Dumper has now an option to sort hashes.
77c8cf41
JH
913
914=item *
915
1e13d81f
JH
916Data::Dumper has now an option to dump code references
917using B::Deparse.
77c8cf41
JH
918
919=item *
920
44da0e71
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921DB_File now supports newer Berkeley DB versions, among
922other improvements.
923
924=item *
925
1e13d81f
JH
926The English module can now be used without the infamous performance
927hit by saying
77c8cf41 928
1e13d81f 929 use English '-no_performance_hit';
77c8cf41 930
1e13d81f
JH
931(Assuming, of course, that one doesn't need the troublesome variables
932C<$`>, C<$&>, or C<$'>.) Also, introduced C<@LAST_MATCH_START> and
933C<@LAST_MATCH_END> English aliases for C<@-> and C<@+>.
77c8cf41
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934
935=item *
936
1e13d81f
JH
937Fcntl, Socket, and Sys::Syslog have been rewritten to use the
938new-style constant dispatch section (see L<ExtUtils::Constant>).
939This means that they will be more robust and hopefully faster.
77c8cf41
JH
940
941=item *
942
44da0e71
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943File::Find now chdir()s correctly when chasing symbolic links.
944
945=item *
946
1e13d81f
JH
947File::Find now has pre- and post-processing callbacks. It also
948correctly changes directories when chasing symbolic links. Callbacks
949(naughtily) exiting with "next;" instead of "return;" now work.
61947107
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950
951=item *
952
1e13d81f
JH
953File::Find is now (again) reentrant. It also has been made
954more portable.
77c8cf41 955
61947107
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956=item *
957
1e13d81f
JH
958File::Glob::glob() renamed to File::Glob::bsd_glob() to avoid
959prototype mismatch with CORE::glob().
61947107
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960
961=item *
962
963File::Glob now supports C<GLOB_LIMIT> constant to limit the size of
964the returned list of filenames.
77c8cf41
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965
966=item *
967
968Devel::Peek now has an interface for the Perl memory statistics
969(this works only if you are using perl's malloc, and if you have
970compiled with debugging).
971
972=item *
973
1e13d81f
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974IPC::Open3 now allows the use of numeric file descriptors.
975
976=item *
977
77c8cf41
JH
978IO::Socket has now atmark() method, which returns true if the socket
979is positioned at the out-of-band mark. The method is also exportable
980as a sockatmark() function.
981
982=item *
983
984IO::Socket::INET has support for ReusePort option (if your platform
985supports it). The Reuse option now has an alias, ReuseAddr. For clarity
986you may want to prefer ReuseAddr.
987
988=item *
989
61947107
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990IO::Socket::INET now supports C<LocalPort> of zero (usually meaning
991that the operating system will make one up.)
77c8cf41
JH
992
993=item *
994
1e13d81f
JH
995use lib now works identically to @INC. Removing directories
996with 'no lib' now works.
997
998=item *
999
58175c9b
JH
1000ExtUtils::MakeMaker now uses File::Spec internally, which hopefully
1001leads into better portability.
1002
1003=item *
1004
1e13d81f
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1005Math::BigFloat and Math::BigInt have undergone a full rewrite.
1006They are now magnitudes faster, and they support various
61947107 1007bignum libraries such as GMP and PARI as their backends.
f39f21d8
JH
1008
1009=item *
1010
44da0e71
JH
1011Math::Complex handles inf, NaN etc., better.
1012
1013=item *
1014
58175c9b
JH
1015Net::Ping has been muchly enhanced. Multihoming is now supported.
1016There is now "external" protocol which uses Net::Ping::External module
1017which runs external ping(1) and parses the output. A version of
1018Net::Ping::External is available in CPAN.
f39f21d8 1019
77c8cf41 1020=item *
f39f21d8 1021
da6838c8 1022POSIX::sigaction() is now much more flexible and robust.
61947107
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1023You can now install coderef handlers, 'DEFAULT', and 'IGNORE'
1024handlers, installing new handlers was not atomic.
f39f21d8
JH
1025
1026=item *
1027
da6838c8 1028In Safe the C<%INC> now localised in a Safe compartment so that
76663d67
JH
1029use/require work.
1030
1031=item *
1032
44da0e71
JH
1033In SDBM_File on dosish platforms, some keys went missing because of
1034lack of support for files with "holes". A workaround for the problem
1035has been added.
1036
1037=item *
1038
da6838c8 1039In Search::Dict one can now have a pre-processing hook for the
76663d67 1040lines being searched.
1e13d81f
JH
1041
1042=item *
1043
1044The Shell module now has an OO interface.
1045
1046=item *
1047
61947107 1048The Test module has been significantly enhanced.
f39f21d8
JH
1049
1050=item *
1051
da6838c8 1052The vars pragma now supports declaring fully qualified variables.
77c8cf41 1053(Something that C<our()> does not and will not support.)
f39f21d8 1054
888aee59
JH
1055=item *
1056
58175c9b 1057The C<utf8::> name space (as in the pragma) provides various
61947107
JH
1058Perl-callable functions to provide low level access to Perl's
1059internal Unicode representation. At the moment only length()
1060has been implemented.
888aee59 1061
f39f21d8
JH
1062=back
1063
77c8cf41 1064=head1 Utility Changes
f39f21d8
JH
1065
1066=over 4
1067
1068=item *
1069
61947107 1070Emacs perl mode (emacs/cperl-mode.el) has been updated to version
77c8cf41 10714.31.
f39f21d8
JH
1072
1073=item *
1074
61947107 1075F<emacs/e2ctags.pl> is now much faster.
f39f21d8
JH
1076
1077=item *
1078
1e13d81f
JH
1079C<h2ph> now supports C trigraphs.
1080
1081=item *
1082
1083C<h2xs> now produces a template README.
f39f21d8 1084
77c8cf41
JH
1085=item *
1086
1e13d81f
JH
1087C<h2xs> now uses C<Devel::PPort> for better portability between
1088different versions of Perl.
f39f21d8
JH
1089
1090=item *
1091
1e13d81f 1092C<h2xs> uses the new L<ExtUtils::Constant> module which will affect
61947107
JH
1093newly created extensions that define constants. Since the new code is
1094more correct (if you have two constants where the first one is a
1095prefix of the second one, the first constant B<never> gets defined),
1096less lossy (it uses integers for integer constant, as opposed to the
1097old code that used floating point numbers even for integer constants),
1098and slightly faster, you might want to consider regenerating your
1099extension code (the new scheme makes regenerating easy).
1100L<h2xs> now also supports C trigraphs.
f39f21d8
JH
1101
1102=item *
1103
1e13d81f 1104C<libnetcfg> has been added to configure the libnet.
f39f21d8
JH
1105
1106=item *
1107
1e13d81f 1108C<perlbug> is now much more robust. It also sends the bug report to
61947107 1109perl.org, not perl.com.
f39f21d8
JH
1110
1111=item *
1112
1e13d81f 1113C<perlcc> has been rewritten and its user interface (that is,
61947107 1114command line) is much more like that of the UNIX C compiler, cc.
44da0e71 1115(The perlbc tools has been removed. Use C<perlcc -B> instead.)
f39f21d8
JH
1116
1117=item *
1118
aecce728
JH
1119C<perlivp> is a new Installation Verification Procedure utility
1120for running any time after installing Perl.
f39f21d8
JH
1121
1122=item *
1123
1e13d81f 1124C<pod2html> now allows specifying a cache directory.
f39f21d8
JH
1125
1126=item *
1127
1e13d81f
JH
1128C<s2p> has been completely rewritten in Perl. (It is in fact a full
1129implementation of sed in Perl: you can use the sed functionality by
1130using the C<psed> utility.)
61947107
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1131
1132=item *
1133
1e13d81f 1134C<xsubpp> now understands POD documentation embedded in the *.xs files.
f39f21d8
JH
1135
1136=item *
1137
1e13d81f 1138C<xsubpp> now supports OUT keyword.
f39f21d8
JH
1139
1140=back
1141
77c8cf41 1142=head1 New Documentation
f39f21d8
JH
1143
1144=over 4
1145
1146=item *
1147
77c8cf41
JH
1148perl56delta details the changes between the 5.005 release and the
11495.6.0 release.
f39f21d8
JH
1150
1151=item *
1152
61947107
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1153perlclib documents the internal replacements for standard C library
1154functions. (Interesting only for extension writers and Perl core
1155hackers.)
1156
1157=item *
1158
77c8cf41 1159perldebtut is a Perl debugging tutorial.
f39f21d8 1160
77c8cf41 1161=item *
f39f21d8 1162
77c8cf41 1163perlebcdic contains considerations for running Perl on EBCDIC platforms.
f39f21d8 1164
77c8cf41
JH
1165=item *
1166
888aee59
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1167perlintro is a gentle introduction to Perl.
1168
1169=item *
1170
61947107
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1171perliol documents the internals of PerlIO with layers.
1172
1173=item *
1174
888aee59
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1175perlmodstyle is a style guide for writing modules.
1176
1177=item *
1178
77c8cf41 1179perlnewmod tells about writing and submitting a new module.
f39f21d8
JH
1180
1181=item *
1182
34babc16
JH
1183perlpacktut is a pack() tutorial.
1184
1185=item *
1186
888aee59
JH
1187perlpod has been rewritten to be clearer and to record the best
1188practices gathered over the years.
1189
1190=item *
1191
057b7f2b 1192perlpodspec is a more formal specification of the pod format,
888aee59
JH
1193mainly of interest for writers of pod applications, not to
1194people writing in pod.
1195
1196=item *
1197
77c8cf41 1198perlretut is a regular expression tutorial.
f39f21d8
JH
1199
1200=item *
1201
77c8cf41
JH
1202perlrequick is a regular expressions quick-start guide.
1203Yes, much quicker than perlretut.
f39f21d8 1204
77c8cf41 1205=item *
f39f21d8 1206
61947107
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1207perltodo has been updated.
1208
1209=item *
1210
888aee59 1211perltootc has been renamed as perltooc (to not to conflict
61947107 1212with perltoot in filesystems restricted to "8.3" names)
888aee59
JH
1213
1214=item *
1215
58175c9b
JH
1216perluniintro is an introduction to using Unicode in Perl.
1217(perlunicode is more of a detailed reference and background
1218information)
888aee59
JH
1219
1220=item *
1221
77c8cf41
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1222perlutil explains the command line utilities packaged with the Perl
1223distribution.
1224
1225=back
f39f21d8 1226
61947107
JH
1227The following platform-specific documents are available before
1228the installation as README.I<platform>, and after the installation
1229as perlI<platform>:
f39f21d8 1230
61947107
JH
1231 perlaix perlamiga perlapollo perlbeos perlbs2000
1232 perlce perlcygwin perldgux perldos perlepoc perlhpux
1233 perlhurd perlmachten perlmacos perlmint perlmpeix
1234 perlnetware perlos2 perlos390 perlplan9 perlqnx perlsolaris
1235 perltru64 perluts perlvmesa perlvms perlvos perlwin32
77c8cf41
JH
1236
1237=over 4
1238
1239=item *
1240
61947107
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1241The documentation for the POSIX-BC platform is called "BS2000", to avoid
1242confusion with the Perl POSIX module.
77c8cf41
JH
1243
1244=item *
1245
61947107
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1246The documentation for the WinCE platform is called "CE", to avoid
1247confusion with the perlwin32 documentation on 8.3-restricted filesystems.
77c8cf41
JH
1248
1249=back
1250
1251=head1 Performance Enhancements
1252
1253=over 4
1254
1255=item *
1256
44da0e71
JH
1257map() could get pathologically slow when the result list it generates
1258is larger than the source list. The performance has been improved for
1259common scenarios.
77c8cf41
JH
1260
1261=item *
1262
e1f170bd
JH
1263sort() has been changed to use primarily mergesort internally as
1264opposed to the earlier quicksort. For very small lists this may
1265result in slightly slower sorting times, but in general the speedup
1266should be at least 20%. Additional bonuses are that the worst case
1267behaviour of sort() is now better (in computer science terms it now
1268runs in time O(N log N), as opposed to quicksort's Theta(N**2)
1269worst-case run time behaviour), and that sort() is now stable
1270(meaning that elements with identical keys will stay ordered as they
1271were before the sort). See the C<sort> pragma for information.
77c8cf41 1272
05e25c75
JH
1273The story in more detail: suppose you want to serve yourself a little
1274slice of Pi.
1275
1276 @digits = ( 3,1,4,1,5,9 );
1277
1278A numerical sort of the digits will yield (1,1,3,4,5,9), as expected.
1279Which C<1> comes first is hard to know, since one C<1> looks pretty
1280much like any other. You can regard this as totally trivial,
1281or somewhat profound. However, if you just want to sort the even
1282digits ahead of the odd ones, then what will
1283
1284 sort { ($a % 2) <=> ($b % 2) } @digits;
1285
1286yield? The only even digit, C<4>, will come first. But how about
1287the odd numbers, which all compare equal? With the quicksort algorithm
1288used to implement Perl 5.6 and earlier, the order of ties is left up
1289to the sort. So, as you add more and more digits of Pi, the order
1290in which the sorted even and odd digits appear will change.
1291and, for sufficiently large slices of Pi, the quicksort algorithm
1292in Perl 5.8 won't return the same results even if reinvoked with the
1293same input. The justification for this rests with quicksort's
1294worst case behavior. If you run
1295
1296 sort { $a <=> $b } ( 1 .. $N , 1 .. $N );
1297
1298(something you might approximate if you wanted to merge two sorted
1299arrays using sort), doubling $N doesn't just double the quicksort time,
1300it I<quadruples> it. Quicksort has a worst case run time that can
1301grow like N**2, so-called I<quadratic> behaviour, and it can happen
1302on patterns that may well arise in normal use. You won't notice this
1303for small arrays, but you I<will> notice it with larger arrays,
1304and you may not live long enough for the sort to complete on arrays
1305of a million elements. So the 5.8 quicksort scrambles large arrays
1306before sorting them, as a statistical defence against quadratic behaviour.
1307But that means if you sort the same large array twice, ties may be
1308broken in different ways.
1309
1310Because of the unpredictability of tie-breaking order, and the quadratic
1311worst-case behaviour, quicksort was I<almost> replaced completely with
1312a stable mergesort. I<Stable> means that ties are broken to preserve
1313the original order of appearance in the input array. So
1314
1315 sort { ($a % 2) <=> ($b % 2) } (3,1,4,1,5,9);
1316
1317will yield (4,3,1,1,5,9), guaranteed. The even and odd numbers
1318appear in the output in the same order they appeared in the input.
1319Mergesort has worst case O(NlogN) behaviour, the best value
1320attainable. And, ironically, this mergesort does particularly
1321well where quicksort goes quadratic: mergesort sorts (1..$N, 1..$N)
1322in O(N) time. But quicksort was rescued at the last moment because
1323it is faster than mergesort on certain inputs and platforms.
1324For example, if you really I<don't> care about the order of even
1325and odd digits, quicksort will run in O(N) time; it's very good
1326at sorting many repetitions of a small number of distinct elements.
1327The quicksort divide and conquer strategy works well on platforms
1328with relatively small, very fast, caches. Eventually, the problem gets
1329whittled down to one that fits in the cache, from which point it
1330benefits from the increased memory speed.
1331
1332Quicksort was rescued by implementing a sort pragma to control aspects
1333of the sort. The B<stable> subpragma forces stable behaviour,
1334regardless of algorithm. The B<_quicksort> and B<_mergesort>
1335subpragmas are heavy-handed ways to select the underlying implementation.
1336The leading C<_> is a reminder that these subpragmas may not survive
1337beyond 5.8. More appropriate mechanisms for selecting the implementation
1338exist, but they wouldn't have arrived in time to save quicksort.
1339
77c8cf41
JH
1340=item *
1341
1342Hashes now use Bob Jenkins "One-at-a-Time" hashing key algorithm
1343(http://burtleburtle.net/bob/hash/doobs.html). This algorithm is
1344reasonably fast while producing a much better spread of values than
1345the old hashing algorithm (originally by Chris Torek, later tweaked by
1346Ilya Zakharevich). Hash values output from the algorithm on a hash of
1347all 3-char printable ASCII keys comes much closer to passing the
1348DIEHARD random number generation tests. According to perlbench, this
1349change has not affected the overall speed of Perl.
1350
1351=item *
1352
1353unshift() should now be noticeably faster.
1354
1355=back
1356
1357=head1 Installation and Configuration Improvements
1358
1359=head2 Generic Improvements
1360
1361=over 4
1362
1363=item *
1364
1365INSTALL now explains how you can configure Perl to use 64-bit
1366integers even on non-64-bit platforms.
1367
1368=item *
1369
1370Policy.sh policy change: if you are reusing a Policy.sh file
1371(see INSTALL) and you use Configure -Dprefix=/foo/bar and in the old
1372Policy $prefix eq $siteprefix and $prefix eq $vendorprefix, all of
1373them will now be changed to the new prefix, /foo/bar. (Previously
1374only $prefix changed.) If you do not like this new behaviour,
1375specify prefix, siteprefix, and vendorprefix explicitly.
1376
1377=item *
1378
1379A new optional location for Perl libraries, otherlibdirs, is available.
1380It can be used for example for vendor add-ons without disturbing Perl's
1381own library directories.
1382
1383=item *
1384
1385In many platforms the vendor-supplied 'cc' is too stripped-down to
1386build Perl (basically, 'cc' doesn't do ANSI C). If this seems
1387to be the case and 'cc' does not seem to be the GNU C compiler
1388'gcc', an automatic attempt is made to find and use 'gcc' instead.
1389
1390=item *
1391
1392gcc needs to closely track the operating system release to avoid
1393build problems. If Configure finds that gcc was built for a different
1394operating system release than is running, it now gives a clearly visible
1395warning that there may be trouble ahead.
1396
1397=item *
1398
1399If binary compatibility with the 5.005 release is not wanted, Configure
1400no longer suggests including the 5.005 modules in @INC.
1401
1402=item *
1403
1404Configure C<-S> can now run non-interactively.
1405
1406=item *
1407
44da0e71
JH
1408Configure support for pdp11-style memory models has been removed due
1409to obsolescence.
1410
1411=item *
1412
77c8cf41 1413configure.gnu now works with options with whitespace in them.
f39f21d8 1414
77c8cf41 1415=item *
f39f21d8 1416
77c8cf41 1417installperl now outputs everything to STDERR.
f39f21d8 1418
77c8cf41
JH
1419=item *
1420
1421$Config{byteorder} is now computed dynamically (this is more robust
1422with "fat binaries" where an executable image contains binaries for
1423more than one binary platform.)
f39f21d8
JH
1424
1425=item *
1426
1427Because PerlIO is now the default on most platforms, "-perlio" doesn't
1428get appended to the $Config{archname} (also known as $^O) anymore.
1429Instead, if you explicitly choose not to use perlio (Configure command
1430line option -Uuseperlio), you will get "-stdio" appended.
1431
1432=item *
1433
1434Another change related to the architecture name is that "-64all"
1435(-Duse64bitall, or "maximally 64-bit") is appended only if your
1436pointers are 64 bits wide. (To be exact, the use64bitall is ignored.)
1437
1438=item *
1439
77c8cf41
JH
1440In AFS installations one can configure the root of the AFS to be
1441somewhere else than the default F</afs> by using the Configure
1442parameter C<-Dafsroot=/some/where/else>.
1443
1444=item *
1445
61947107
JH
1446APPLLIB_EXP, a less-know configuration-time definition, has been
1447documented. It can be used to prepend site-specific directories
1448to Perl's default search path (@INC), see INSTALL for information.
1449
1450=item *
1451
77c8cf41
JH
1452The version of Berkeley DB used when the Perl (and, presumably, the
1453DB_File extension) was built is now available as
1454C<@Config{qw(db_version_major db_version_minor db_version_patch)}>
1455from Perl and as C<DB_VERSION_MAJOR_CFG DB_VERSION_MINOR_CFG
1456DB_VERSION_PATCH_CFG> from C.
1457
1458=item *
1459
61947107
JH
1460Building Berkeley DB3 for compatibility modes for DB, NDBM, and ODBM
1461has been documented in INSTALL.
77c8cf41
JH
1462
1463=item *
1464
61947107
JH
1465If you have CPAN access (either network or a local copy such as a
1466CD-ROM) you can during specify extra modules to Configure to build and
1467install with Perl using the -Dextras=... option. See INSTALL for
1468more details.
f39f21d8 1469
61947107 1470=item *
f39f21d8 1471
61947107
JH
1472In addition to config.over a new override file, config.arch, is
1473available. That is supposed to be used by hints file writers for
1474architecture-wide changes (as opposed to config.over which is for
1475site-wide changes).
f39f21d8
JH
1476
1477=item *
1478
e1f170bd
JH
1479If your file system supports symbolic links you can build Perl outside
1480of the source directory by
1481
1482 mkdir /tmp/perl/build/directory
1483 cd /tmp/perl/build/directory
1484 sh /path/to/perl/source/Configure -Dmksymlinks ...
1485
1486This will create in /tmp/perl/build/directory a tree of symbolic links
1487pointing to files in /path/to/perl/source. The original files are left
1488unaffected. After Configure has finished you can just say
1489
1490 make all test
1491
1492and Perl will be built and tested, all in /tmp/perl/build/directory.
1493
1494=item *
1495
61947107
JH
1496For Perl developers several new make targets for profiling
1497and debugging have been added, see L<perlhack>.
1498
1499=over 8
f39f21d8
JH
1500
1501=item *
1502
61947107
JH
1503Use of the F<gprof> tool to profile Perl has been documented in
1504L<perlhack>. There is a make target called "perl.gprof" for
1505generating a gprofiled Perl executable.
f39f21d8
JH
1506
1507=item *
1508
61947107
JH
1509If you have GCC 3, there is a make target called "perl.gcov" for
1510creating a gcoved Perl executable for coverage analysis. See
1511L<perlhack>.
f39f21d8
JH
1512
1513=item *
1514
61947107
JH
1515If you are on IRIX or Tru64 platforms, new profiling/debugging options
1516have been added, see L<perlhack> for more information about pixie and
1517Third Degree.
1518
1519=back
f39f21d8
JH
1520
1521=item *
1522
61947107
JH
1523Guidelines of how to construct minimal Perl installations have
1524been added to INSTALL.
f39f21d8
JH
1525
1526=item *
1527
61947107
JH
1528The Thread extension is now not built at all under ithreads
1529(C<Configure -Duseithreads>) because it wouldn't work anyway (the
1530Thread extension requires being Configured with C<-Duse5005threads>).
f39f21d8 1531
61947107
JH
1532But note that the Thread.pm interface is now shared by both
1533thread models.
f39f21d8 1534
61947107 1535=back
f39f21d8 1536
61947107 1537=head2 New Or Improved Platforms
f39f21d8 1538
61947107
JH
1539For the list of platforms known to support Perl,
1540see L<perlport/"Supported Platforms">.
1541
1542=over 4
f39f21d8
JH
1543
1544=item *
1545
61947107 1546AIX dynamic loading should be now better supported.
f39f21d8 1547
f39f21d8
JH
1548=item *
1549
77c8cf41
JH
1550AIX should now work better with gcc, threads, and 64-bitness. Also the
1551long doubles support in AIX should be better now. See L<perlaix>.
f39f21d8
JH
1552
1553=item *
1554
61947107
JH
1555After a long pause, AmigaOS has been verified to be happy with Perl.
1556
1557=item *
1558
77c8cf41 1559AtheOS (http://www.atheos.cx/) is a new platform.
f39f21d8 1560
77c8cf41 1561=item *
f39f21d8 1562
58175c9b
JH
1563BeOS has been reclaimed.
1564
1565=item *
1566
77c8cf41 1567DG/UX platform now supports the 5.005-style threads. See L<perldgux>.
f39f21d8
JH
1568
1569=item *
1570
77c8cf41 1571DYNIX/ptx platform (a.k.a. dynixptx) is supported at or near osvers 4.5.2.
f39f21d8
JH
1572
1573=item *
1574
61947107
JH
1575EBCDIC platforms (z/OS, also known as OS/390, POSIX-BC, and VM/ESA)
1576have been regained. Many test suite tests still fail and the
1577co-existence of Unicode and EBCDIC isn't quite settled, but the
1578situation is much better than with Perl 5.6. See L<perlos390>,
1579L<perlbs2000> (for POSIX-BC), and L<perlvmesa> for more information.
f39f21d8
JH
1580
1581=item *
1582
61947107
JH
1583Building perl with -Duseithreads or -Duse5005threads now works under
1584HP-UX 10.20 (previously it only worked under 10.30 or later). You will
1585need a thread library package installed. See README.hpux.
f39f21d8 1586
77c8cf41 1587=item *
f39f21d8 1588
61947107
JH
1589MacOS Classic (MacPerl has of course been available since
1590perl 5.004 but now the source code bases of standard Perl
1591and MacPerl have been synchronised)
f39f21d8 1592
77c8cf41 1593=item *
f39f21d8 1594
61947107
JH
1595MacOS X (or Darwin) should now be able to build Perl even on HFS+
1596filesystems. (The case-insensitivity confused the Perl build process.)
f39f21d8 1597
888aee59
JH
1598=item *
1599
61947107 1600NCR MP-RAS is now supported.
888aee59
JH
1601
1602=item *
1603
58175c9b
JH
1604All the NetBSD specific patches (except for the installation
1605specific ones) have been merged back to the main distribution.
1606
1607=item *
1608
61947107 1609NetWare from Novell is now supported. See L<perlnetware>.
888aee59
JH
1610
1611=item *
1612
61947107 1613NonStop-UX is now supported.
888aee59
JH
1614
1615=item *
1616
44da0e71
JH
1617NEC SUPER-UX is now supported.
1618
1619=item *
1620
58175c9b
JH
1621All the OpenBSD specific patches (except for the installation
1622specific ones) have been merged back to the main distribution.
1623
1624=item *
1625
1626Perl has been tested with the GNU pth userlevel thread package
1627( http://www.gnu.org/software/pth/pth.html ) . All but one thread
1628test worked, and that one failure was because of test results arriving
1629in unexpected order.
1630
1631=item *
1632
61947107 1633Amdahl UTS UNIX mainframe platform is now supported.
888aee59
JH
1634
1635=item *
1636
61947107
JH
1637WinCE is now supported. See L<perlce>.
1638
1639=item *
1640
1641z/OS (formerly known as OS/390, formerly known as MVS OE) has now
1642support for dynamic loading. This is not selected by default,
1643however, you must specify -Dusedl in the arguments of Configure.
888aee59 1644
f39f21d8
JH
1645=back
1646
1647=head1 Selected Bug Fixes
1648
e1f170bd
JH
1649Numerous memory leaks and uninitialized memory accesses have been
1650hunted down. Most importantly anonymous subs used to leak quite
1651a bit.
ba370e9b 1652
f39f21d8
JH
1653=over 4
1654
1655=item *
1656
e1f170bd 1657The autouse pragma didn't work for Multi::Part::Function::Names.
f39f21d8
JH
1658
1659=item *
1660
44da0e71
JH
1661caller() could cause core dumps in certain situations. Carp was sometimes
1662affected by this problem.
1663
1664=item *
1665
e1f170bd
JH
1666chop(@list) in list context returned the characters chopped in
1667reverse order. This has been reversed to be in the right order.
f39f21d8
JH
1668
1669=item *
1670
e1f170bd
JH
1671Configure no longer includes the DBM libraries (dbm, gdbm, db, ndbm)
1672when building the Perl binary. The only exception to this is SunOS 4.x,
1673which needs them.
f39f21d8
JH
1674
1675=item *
1676
e1f170bd
JH
1677The behaviour of non-decimal but numeric string constants such as
1678"0x23" was platform-dependent: in some platforms that was seen as 35,
1679in some as 0, in some as a floating point number (don't ask). This
1680was caused by Perl using the operating system libraries in a situation
1681where the result of the string to number conversion is undefined: now
1682Perl consistently handles such strings as zero in numeric contexts.
f39f21d8
JH
1683
1684=item *
1685
e1f170bd 1686The order of DESTROYs has been made more predictable.
f39f21d8
JH
1687
1688=item *
1689
e1f170bd
JH
1690Several debugger fixes: exit code now reflects the script exit code,
1691condition C<"0"> now treated correctly, the C<d> command now checks
44da0e71
JH
1692line number, the C<$.> no longer gets corrupted, all debugger output
1693now goes correctly to the socket if RemotePort is set.
1694
1695=item *
1696
1697Perl 5.6.0 could emit spurious warnings about redefinition of dl_error()
1698when statically building extensions into perl. This has been corrected.
f39f21d8
JH
1699
1700=item *
1701
e1f170bd 1702L<dprofpp> -R didn't work.
f39f21d8
JH
1703
1704=item *
1705
e1f170bd 1706C<*foo{FORMAT}> now works.
44da0e71
JH
1707=item *
1708
1709Infinity is now recognized as a number.
f39f21d8
JH
1710
1711=item *
1712
e1f170bd
JH
1713UNIVERSAL::isa no longer caches methods incorrectly. (This broke
1714the Tk extension with 5.6.0.)
f39f21d8
JH
1715
1716=item *
1717
e1f170bd
JH
1718Lexicals I: lexicals outside an eval "" weren't resolved
1719correctly inside a subroutine definition inside the eval "" if they
1720were not already referenced in the top level of the eval""ed code.
f39f21d8
JH
1721
1722=item *
1723
e1f170bd
JH
1724Lexicals II: lexicals leaked at file scope into subroutines that
1725were declared before the lexicals.
f39f21d8
JH
1726
1727=item *
1728
44da0e71
JH
1729Lexical warnings now propagating correctly between scopes
1730and into C<eval "...">.
1731
1732=item *
1733
1734C<use warnings qw(FATAL all)> did not work as intended. This has been
1735corrected.
1736
1737=item *
1738
1739warnings::enabled() now reports the state of $^W correctly if the caller
1740isn't using lexical warnings.
f39f21d8
JH
1741
1742=item *
1743
e1f170bd 1744Line renumbering with eval and C<#line> now works.
f39f21d8
JH
1745
1746=item *
1747
e1f170bd 1748Fixed numerous memory leaks, especially in eval "".
f39f21d8
JH
1749
1750=item *
1751
e1f170bd
JH
1752mkdir() now ignores trailing slashes in the directory name,
1753as mandated by POSIX.
f39f21d8
JH
1754
1755=item *
1756
e1f170bd
JH
1757Some versions of glibc have a broken modfl(). This affects builds
1758with C<-Duselongdouble>. This version of Perl detects this brokenness
1759and has a workaround for it. The glibc release 2.2.2 is known to have
1760fixed the modfl() bug.
f39f21d8
JH
1761
1762=item *
1763
e1f170bd
JH
1764Modulus of unsigned numbers now works (4063328477 % 65535 used to
1765return 27406, instead of 27047).
f39f21d8
JH
1766
1767=item *
1768
e1f170bd
JH
1769Some "not a number" warnings introduced in 5.6.0 eliminated to be
1770more compatible with 5.005. Infinity is now recognised as a number.
f39f21d8 1771
77c8cf41 1772=item *
f39f21d8 1773
44da0e71
JH
1774Numeric conversions did not recognize changes in the string value
1775properly in certain circumstances.
1776
1777=item *
1778
e1f170bd 1779Attributes (like :shared) didn't work with our().
f39f21d8
JH
1780
1781=item *
1782
e1f170bd 1783our() variables will not cause "will not stay shared" warnings.
f39f21d8
JH
1784
1785=item *
1786
44da0e71
JH
1787"our" variables of the same name declared in two sibling blocks
1788resulted in bogus warnings about "redeclaration" of the variables.
1789The problem has been corrected.
1790
1791=item *
1792
e1f170bd 1793pack "Z" now correctly terminates the string with "\0".
f39f21d8
JH
1794
1795=item *
1796
e1f170bd
JH
1797Fix password routines which in some shadow password platforms
1798(e.g. HP-UX) caused getpwent() to return every other entry.
f39f21d8 1799
77c8cf41 1800=item *
f39f21d8 1801
e1f170bd
JH
1802The PERL5OPT environment variable (for passing command line arguments
1803to Perl) didn't work for more than a single group of options.
f39f21d8 1804
77c8cf41 1805=item *
f39f21d8 1806
e1f170bd 1807PERL5OPT with embedded spaces didn't work.
f39f21d8 1808
77c8cf41 1809=item *
f39f21d8 1810
e1f170bd 1811printf() no longer resets the numeric locale to "C".
f39f21d8 1812
77c8cf41 1813=item *
f39f21d8 1814
44da0e71
JH
1815C<qw(a\\b)> now parses correctly as C<'a\\b'>.
1816
1817=item *
1818
1819pos() did not return the correct value within s///ge in earlier
1820versions. This is now handled correctly.
f39f21d8 1821
77c8cf41 1822=item *
f39f21d8 1823
e1f170bd
JH
1824Printing quads (64-bit integers) with printf/sprintf now works
1825without the q L ll prefixes (assuming you are on a quad-capable platform).
f39f21d8 1826
77c8cf41 1827=item *
f39f21d8 1828
e1f170bd 1829Regular expressions on references and overloaded scalars now work.
f39f21d8 1830
ba370e9b
JH
1831=item *
1832
e1f170bd
JH
1833Right-hand side magic (GMAGIC) could in many cases such as string
1834concatenation be invoked too many times.
ba370e9b
JH
1835
1836=item *
1837
e1f170bd 1838scalar() now forces scalar context even when used in void context.
ba370e9b
JH
1839
1840=item *
1841
e1f170bd 1842SOCKS support is now much more robust.
ba370e9b
JH
1843
1844=item *
1845
e1f170bd
JH
1846sort() arguments are now compiled in the right wantarray context
1847(they were accidentally using the context of the sort() itself).
44da0e71
JH
1848The comparison block is now run in scalar context, and the arguments
1849to be sorted are always provided list context.
ba370e9b
JH
1850
1851=item *
1852
e1f170bd 1853Changed the POSIX character class C<[[:space:]]> to include the (very
c2e23569
JH
1854rarely used) vertical tab character. Added a new POSIX-ish character
1855class C<[[:blank:]]> which stands for horizontal whitespace
1856(currently, the space and the tab).
ba370e9b
JH
1857
1858=item *
1859
1860The tainting behaviour of sprintf() has been rationalized. It does
1861not taint the result of floating point formats anymore, making the
1862behaviour consistent with that of string interpolation.
1863
1864=item *
1865
44da0e71
JH
1866Some cases of inconsistent taint propagation (such as within hash
1867values) have been fixed.
1868
1869=item *
1870
1871The RE engine found in Perl 5.6.0 accidentally pessimised certain kinds
1872of simple pattern matches. These are now handled better.
1873
1874=item *
1875
1876Regular expression debug output (whether through C<use re 'debug'>
1877or via C<-Dr>) now looks better.
1878
1879=item *
1880
1881Multi-line matches like C<"a\nxb\n" =~ /(?!\A)x/m> were flawed. The
1882bug has been fixed.
1883
1884=item *
1885
1886Use of $& could trigger a core dump under some situations. This
1887is now avoided.
1888
1889=item *
1890
c2e23569
JH
1891The regular expression captured submatches ($1, $2, ...) are now
1892more consistently unset if the match fails, instead of leaving false
1893data lying around in them.
1894
1895=item *
1896
44da0e71
JH
1897readline() on files opened in "slurp" mode could return an extra "" at
1898the end in certain situations. This has been corrected.
1899
1900=item *
1901
1902Autovivification of symbolic references of special variables described
1903in L<perlvar> (as in C<${$num}>) was accidentally disabled. This works
1904again now.
1905
1906=item *
1907
da6838c8 1908Sys::Syslog ignored the C<LOG_AUTH> constant.
ba370e9b
JH
1909
1910=item *
1911
e1f170bd 1912All but the first argument of the IO syswrite() method are now optional.
ba370e9b
JH
1913
1914=item *
1915
e1f170bd
JH
1916$AUTOLOAD, sort(), lock(), and spawning subprocesses
1917in multiple threads simultaneously are now thread-safe.
ba370e9b
JH
1918
1919=item *
1920
e1f170bd 1921Tie::ARRAY SPLICE method was broken.
ba370e9b
JH
1922
1923=item *
1924
e1f170bd 1925Allow read-only string on left hand side of non-modifying tr///.
ba370e9b
JH
1926
1927=item *
1928
e1f170bd 1929Several Unicode fixes.
ba370e9b
JH
1930
1931=over 8
1932
1933=item *
1934
e1f170bd
JH
1935BOMs (byte order marks) in the beginning of Perl files
1936(scripts, modules) should now be transparently skipped.
1937UTF-16 (UCS-2) encoded Perl files should now be read correctly.
ba370e9b
JH
1938
1939=item *
1940
e1f170bd 1941The character tables have been updated to Unicode 3.1.1.
ba370e9b
JH
1942
1943=item *
1944
e1f170bd 1945Comparing with utf8 data does not magically upgrade non-utf8 data
58175c9b
JH
1946into utf8. (This was a problem for example if you were mixing data
1947from I/O and Unicode data: your output might have got magically encoded
1948as UTF-8.)
1949
1950=item *
1951
1952Generating illegal Unicode code points like U+FFFE, or the UTF-16
1953surrogates, now also generates an optional warning.
ba370e9b
JH
1954
1955=item *
1956
e1f170bd 1957C<IsAlnum>, C<IsAlpha>, and C<IsWord> now match titlecase.
f39f21d8 1958
77c8cf41 1959=item *
f39f21d8 1960
e1f170bd
JH
1961Concatenation with the C<.> operator or via variable interpolation,
1962C<eq>, C<substr>, C<reverse>, C<quotemeta>, the C<x> operator,
1963substitution with C<s///>, single-quoted UTF8, should now work.
f39f21d8 1964
77c8cf41 1965=item *
f39f21d8 1966
e1f170bd
JH
1967The C<tr///> operator now works. Note that the C<tr///CU>
1968functionality has been removed (but see pack('U0', ...)).
f39f21d8 1969
77c8cf41 1970=item *
f39f21d8 1971
e1f170bd 1972C<eval "v200"> now works.
f39f21d8 1973
77c8cf41 1974=item *
f39f21d8 1975
44da0e71
JH
1976Perl 5.6.0 parsed m/\x{ab}/ incorrectly, leading to spurious warnings.
1977This has been corrected.
1978
1979=item *
1980
e1f170bd 1981Zero entries were missing from the Unicode classes like C<IsDigit>.
f39f21d8 1982
e1f170bd 1983=back
f39f21d8 1984
44da0e71
JH
1985=item *
1986
1987Large unsigned numbers (those above 2**31) could sometimes lose their
1988unsignedness, causing bogus results in arithmetic operations.
1989
77c8cf41 1990=back
f39f21d8 1991
77c8cf41 1992=head2 Platform Specific Changes and Fixes
f39f21d8
JH
1993
1994=over 4
1995
1996=item *
1997
77c8cf41 1998BSDI 4.*
f39f21d8 1999
77c8cf41 2000Perl now works on post-4.0 BSD/OSes.
f39f21d8
JH
2001
2002=item *
2003
77c8cf41 2004All BSDs
f39f21d8 2005
057b7f2b 2006Setting C<$0> now works (as much as possible; see L<perlvar> for details).
f39f21d8
JH
2007
2008=item *
2009
77c8cf41 2010Cygwin
f39f21d8 2011
77c8cf41 2012Numerous updates; currently synchronised with Cygwin 1.1.4.
f39f21d8
JH
2013
2014=item *
2015
e1f170bd
JH
2016Previously DYNIX/ptx had problems in its Configure probe for non-blocking I/O.
2017
2018=item *
2019
77c8cf41 2020EPOC
f39f21d8 2021
77c8cf41 2022EPOC update after Perl 5.6.0. See README.epoc.
f39f21d8
JH
2023
2024=item *
2025
77c8cf41 2026FreeBSD 3.*
f39f21d8 2027
77c8cf41 2028Perl now works on post-3.0 FreeBSDs.
f39f21d8
JH
2029
2030=item *
2031
77c8cf41
JH
2032HP-UX
2033
2034README.hpux updated; C<Configure -Duse64bitall> now almost works.
f39f21d8
JH
2035
2036=item *
2037
77c8cf41 2038IRIX
f39f21d8 2039
77c8cf41
JH
2040Numerous compilation flag and hint enhancements; accidental mixing
2041of 32-bit and 64-bit libraries (a doomed attempt) made much harder.
f39f21d8 2042
77c8cf41 2043=item *
f39f21d8 2044
77c8cf41 2045Linux
f39f21d8 2046
e1f170bd
JH
2047=over 8
2048
2049=item *
2050
77c8cf41 2051Long doubles should now work (see INSTALL).
f39f21d8
JH
2052
2053=item *
2054
e1f170bd
JH
2055Linux previously had problems related to sockaddrlen when using
2056accept(), revcfrom() (in Perl: recv()), getpeername(), and getsockname().
2057
2058=back
2059
2060=item *
2061
77c8cf41 2062MacOS Classic
f39f21d8 2063
77c8cf41
JH
2064Compilation of the standard Perl distribution in MacOS Classic should
2065now work if you have the Metrowerks development environment and
2066the missing Mac-specific toolkit bits. Contact the macperl mailing
2067list for details.
f39f21d8
JH
2068
2069=item *
2070
77c8cf41 2071MPE/iX
f39f21d8 2072
77c8cf41 2073MPE/iX update after Perl 5.6.0. See README.mpeix.
f39f21d8
JH
2074
2075=item *
2076
77c8cf41 2077NetBSD/sparc
f39f21d8 2078
77c8cf41 2079Perl now works on NetBSD/sparc.
f39f21d8
JH
2080
2081=item *
2082
77c8cf41 2083OS/2
f39f21d8 2084
77c8cf41 2085Now works with usethreads (see INSTALL).
f39f21d8
JH
2086
2087=item *
2088
77c8cf41 2089Solaris
f39f21d8 2090
77c8cf41 209164-bitness using the Sun Workshop compiler now works.
f39f21d8
JH
2092
2093=item *
2094
77c8cf41 2095Tru64 (aka Digital UNIX, aka DEC OSF/1)
f39f21d8 2096
77c8cf41
JH
2097The operating system version letter now recorded in $Config{osvers}.
2098Allow compiling with gcc (previously explicitly forbidden). Compiling
2099with gcc still not recommended because buggy code results, even with
2100gcc 2.95.2.
f39f21d8
JH
2101
2102=item *
2103
77c8cf41
JH
2104Unicos
2105
2106Fixed various alignment problems that lead into core dumps either
2107during build or later; no longer dies on math errors at runtime;
2108now using full quad integers (64 bits), previously was using
2109only 46 bit integers for speed.
f39f21d8
JH
2110
2111=item *
2112
77c8cf41
JH
2113VMS
2114
2115chdir() now works better despite a CRT bug; now works with MULTIPLICITY
2116(see INSTALL); now works with Perl's malloc.
f39f21d8 2117
00bb525a
CB
2118The tainting of C<%ENV> elements via C<keys> or C<values> was previously
2119unimplemented. It now works as documented.
2120
2121The C<waitpid> emulation has been improved. The worst bug (now fixed)
2122was that a pid of -1 would cause a wildcard search of all processes on
2123the system. The most significant enhancement is that we can now
2124usually get the completion status of a terminated process.
2125
2126POSIX-style signals are now emulated much better on VMS versions prior
2127to 7.0.
2128
2129The C<system> function and backticks operator have improved
2130functionality and better error handling.
2131
f39f21d8
JH
2132=item *
2133
77c8cf41 2134Windows
f39f21d8 2135
77c8cf41 2136=over 8
f39f21d8
JH
2137
2138=item *
2139
77c8cf41 2140accept() no longer leaks memory.
f39f21d8
JH
2141
2142=item *
2143
e1f170bd
JH
2144Borland C++ v5.5 is now a supported compiler that can build Perl.
2145However, the generated binaries continue to be incompatible with those
2146generated by the other supported compilers (GCC and Visual C++).
2147
2148=item *
2149
77c8cf41 2150Better chdir() return value for a non-existent directory.
f39f21d8 2151
77c8cf41 2152=item *
f39f21d8 2153
e1f170bd
JH
2154Duping socket handles with open(F, ">&MYSOCK") now works under Windows 9x.
2155
2156=item *
2157
77c8cf41 2158New %ENV entries now propagate to subprocesses.
f39f21d8
JH
2159
2160=item *
2161
44da0e71
JH
2162Current directory entries in %ENV are now correctly propagated to child
2163processes.
2164
2165=item *
2166
77c8cf41
JH
2167$ENV{LIB} now used to search for libs under Visual C.
2168
2169=item *
2170
44da0e71
JH
2171fork() emulation has been improved in various ways, but still continues
2172to be experimental. See L<perlfork> for known bugs and caveats.
e1f170bd
JH
2173
2174=item *
2175
77c8cf41 2176A failed (pseudo)fork now returns undef and sets errno to EAGAIN.
f39f21d8
JH
2177
2178=item *
2179
44da0e71
JH
2180Win32::GetCwd() correctly returns C:\ instead of C: when at the drive root.
2181Other bugs in chdir() and Cwd::cwd() have also been fixed.
2182
2183=item *
2184
e1f170bd
JH
2185HTML files will be installed in c:\perl\html instead of c:\perl\lib\pod\html
2186
2187=item *
2188
2189The makefiles now provide a single switch to bulk-enable all the features
2190enabled in ActiveState ActivePerl (a popular Win32 binary distribution).
2191
2192=item *
2193
77c8cf41 2194Allow REG_EXPAND_SZ keys in the registry.
f39f21d8
JH
2195
2196=item *
2197
77c8cf41 2198Can now send() from all threads, not just the first one.
f39f21d8
JH
2199
2200=item *
2201
77c8cf41 2202Fake signal handling reenabled, bugs and all.
f39f21d8
JH
2203
2204=item *
2205
44da0e71
JH
2206%SIG has been enabled under USE_ITHREADS, but its use is completely
2207unsupported under all configurations.
2208
2209=item *
2210
77c8cf41
JH
2211Less stack reserved per thread so that more threads can run
2212concurrently. (Still 16M per thread.)
f39f21d8
JH
2213
2214=item *
2215
c2e23569 2216C<File::Spec-&gt;tmpdir()> now prefers C:/temp over /tmp
77c8cf41 2217(works better when perl is running as service).
f39f21d8
JH
2218
2219=item *
2220
77c8cf41 2221Better UNC path handling under ithreads.
f39f21d8
JH
2222
2223=item *
2224
44da0e71
JH
2225wait(), waitpid() and backticks now return the correct exit status under
2226Windows 9x.
f39f21d8
JH
2227
2228=item *
2229
77c8cf41 2230winsock handle leak fixed.
f39f21d8
JH
2231
2232=back
2233
77c8cf41 2234=back
f39f21d8 2235
77c8cf41 2236=head1 New or Changed Diagnostics
f39f21d8 2237
ba370e9b
JH
2238=over 4
2239
2240=item *
2241
77c8cf41
JH
2242All regular expression compilation error messages are now hopefully
2243easier to understand both because the error message now comes before
2244the failed regex and because the point of failure is now clearly
ba370e9b
JH
2245marked by a C<E<lt>-- HERE> marker.
2246
2247=item *
f39f21d8 2248
77c8cf41
JH
2249The various "opened only for", "on closed", "never opened" warnings
2250drop the C<main::> prefix for filehandles in the C<main> package,
bea4d472 2251for example C<STDIN> instead of C<main::STDIN>.
f39f21d8 2252
ba370e9b
JH
2253=item *
2254
77c8cf41
JH
2255The "Unrecognized escape" warning has been extended to include C<\8>,
2256C<\9>, and C<\_>. There is no need to escape any of the C<\w> characters.
f39f21d8 2257
ba370e9b 2258=item *
f39f21d8 2259
77c8cf41
JH
2260Two new debugging options have been added: if you have compiled your
2261Perl with debugging, you can use the -DT and -DR options to trace
2262tokenising and to add reference counts to displaying variables,
2263respectively.
f39f21d8
JH
2264
2265=item *
2266
77c8cf41
JH
2267If an attempt to use a (non-blessed) reference as an array index
2268is made, a warning is given.
f39f21d8
JH
2269
2270=item *
2271
77c8cf41
JH
2272C<push @a;> and C<unshift @a;> (with no values to push or unshift)
2273now give a warning. This may be a problem for generated and evaled
2274code.
f39f21d8 2275
ba370e9b
JH
2276=item *
2277
2278If you try to L<perlfunc/pack> a number less than 0 or larger than 255
2279using the C<"C"> format you will get an optional warning. Similarly
2280for the C<"c"> format and a number less than -128 or more than 127.
2281
2282=item *
2283
2284Certain regex modifiers such as C<(?o)> make sense only if applied to
2285the entire regex. You will an optional warning if you try to do otherwise.
2286
2287=item *
2288
c2e23569
JH
2289Using arrays or hashes as references (e.g. C<< %foo-&gt;{bar} >>
2290has been deprecated for a while. Now you will get an optional warning.
ba370e9b 2291
f39f21d8
JH
2292=back
2293
77c8cf41 2294=head1 Changed Internals
f39f21d8
JH
2295
2296=over 4
2297
2298=item *
2299
77c8cf41
JH
2300perlapi.pod (a companion to perlguts) now attempts to document the
2301internal API.
f39f21d8
JH
2302
2303=item *
2304
77c8cf41
JH
2305You can now build a really minimal perl called microperl.
2306Building microperl does not require even running Configure;
2307C<make -f Makefile.micro> should be enough. Beware: microperl makes
2308many assumptions, some of which may be too bold; the resulting
2309executable may crash or otherwise misbehave in wondrous ways.
2310For careful hackers only.
f39f21d8
JH
2311
2312=item *
2313
c2e23569
JH
2314Added rsignal(), whichsig(), do_join(), op_clear, op_null,
2315ptr_table_clear(), ptr_table_free(), sv_setref_uv(), and several UTF-8
2316interfaces to the publicised API. For the full list of the available
2317APIs see L<perlapi>.
f39f21d8
JH
2318
2319=item *
2320
77c8cf41 2321Made possible to propagate customised exceptions via croak()ing.
f39f21d8 2322
77c8cf41 2323=item *
f39f21d8 2324
95f0a2f1
SB
2325Now xsubs can have attributes just like subs. (Well, at least the
2326built-in attributes.)
f39f21d8
JH
2327
2328=item *
2329
77c8cf41
JH
2330dTHR and djSP have been obsoleted; the former removed (because it's
2331a no-op) and the latter replaced with dSP.
f39f21d8
JH
2332
2333=item *
2334
61947107
JH
2335PERL_OBJECT has been completely removed.
2336
2337=item *
2338
ba370e9b
JH
2339The MAGIC constants (e.g. C<'P'>) have been macrofied
2340(e.g. C<PERL_MAGIC_TIED>) for better source code readability
2341and maintainability.
2342
2343=item *
2344
2345The regex compiler now maintains a structure that identifies nodes in
2346the compiled bytecode with the corresponding syntactic features of the
2347original regex expression. The information is attached to the new
2348C<offsets> member of the C<struct regexp>. See L<perldebguts> for more
2349complete information.
2350
2351=item *
2352
2353The C code has been made much more C<gcc -Wall> clean. Some warning
2354messages still remain in some platforms, so if you are compiling with
2355gcc you may see some warnings about dubious practices. The warnings
2356are being worked on.
2357
2358=item *
2359
2360F<perly.c>, F<sv.c>, and F<sv.h> have now been extensively commented.
2361
2362=item *
2363
61947107
JH
2364Documentation on how to use the Perl source repository has been added
2365to F<Porting/repository.pod>.
f39f21d8 2366
888aee59
JH
2367=item *
2368
c2e23569 2369There are now several profiling make targets.
888aee59 2370
77c8cf41 2371=back
f39f21d8 2372
77c8cf41 2373=head1 Security Vulnerability Closed
f39f21d8 2374
77c8cf41 2375(This change was already made in 5.7.0 but bears repeating here.)
f39f21d8 2376
77c8cf41
JH
2377A potential security vulnerability in the optional suidperl component
2378of Perl was identified in August 2000. suidperl is neither built nor
2379installed by default. As of November 2001 the only known vulnerable
2380platform is Linux, most likely all Linux distributions. CERT and
2381various vendors and distributors have been alerted about the vulnerability.
2382See http://www.cpan.org/src/5.0/sperl-2000-08-05/sperl-2000-08-05.txt
2383for more information.
f39f21d8 2384
77c8cf41
JH
2385The problem was caused by Perl trying to report a suspected security
2386exploit attempt using an external program, /bin/mail. On Linux
2387platforms the /bin/mail program had an undocumented feature which
2388when combined with suidperl gave access to a root shell, resulting in
2389a serious compromise instead of reporting the exploit attempt. If you
2390don't have /bin/mail, or if you have 'safe setuid scripts', or if
2391suidperl is not installed, you are safe.
f39f21d8 2392
77c8cf41
JH
2393The exploit attempt reporting feature has been completely removed from
2394Perl 5.8.0 (and the maintenance release 5.6.1, and it was removed also
2395from all the Perl 5.7 releases), so that particular vulnerability
2396isn't there anymore. However, further security vulnerabilities are,
ba370e9b
JH
2397unfortunately, always possible. The suidperl functionality is most
2398probably going to be removed in Perl 5.10. In any case, suidperl
2399should only be used by security experts who know exactly what they are
2400doing and why they are using suidperl instead of some other solution
2401such as sudo (see http://www.courtesan.com/sudo/).
77c8cf41
JH
2402
2403=head1 New Tests
2404
76663d67
JH
2405Several new tests have been added, especially for the F<lib>
2406subsection. There are now about 34 000 individual tests (spread over
2407about 530 test scripts), in the regression suite (5.6.1 has about
240811700 tests, in 258 test scripts) Many of the new tests are introduced
2409by the new modules, but still in general Perl is now more thoroughly
2410tested.
2411
2412Because of the large number of tests, running the regression suite
2413will take considerably longer time than it used to: expect the suite
2414to take up to 4-5 times longer to run than in perl 5.6. In a really
2415fast machine you can hope to finish the suite in about 5 minutes
2416(wallclock time).
77c8cf41
JH
2417
2418The tests are now reported in a different order than in earlier Perls.
2419(This happens because the test scripts from under t/lib have been moved
2420to be closer to the library/extension they are testing.)
2421
f39f21d8
JH
2422=head1 Known Problems
2423
f39f21d8
JH
2424=head2 AIX
2425
2426=over 4
2427
2428=item *
2429
2430In AIX 4.2 Perl extensions that use C++ functions that use statics
2431may have problems in that the statics are not getting initialized.
2432In newer AIX releases this has been solved by linking Perl with
2433the libC_r library, but unfortunately in AIX 4.2 the said library
2434has an obscure bug where the various functions related to time
2435(such as time() and gettimeofday()) return broken values, and
2436therefore in AIX 4.2 Perl is not linked against the libC_r.
2437
2438=item *
2439
2440vac 5.0.0.0 May Produce Buggy Code For Perl
2441
2442The AIX C compiler vac version 5.0.0.0 may produce buggy code,
2443resulting in few random tests failing, but when the failing tests
2444are run by hand, they succeed. We suggest upgrading to at least
2445vac version 5.0.1.0, that has been known to compile Perl correctly.
2446"lslpp -L|grep vac.C" will tell you the vac version.
2447
2448=back
2449
2450=head2 Amiga Perl Invoking Mystery
2451
2452One cannot call Perl using the C<volume:> syntax, that is, C<perl -v>
057b7f2b 2453works, but for example C<bin:perl -v> doesn't. The exact reason isn't
f39f21d8
JH
2454known but the current suspect is the F<ixemul> library.
2455
2456=head2 lib/ftmp-security tests warn 'system possibly insecure'
2457
2458Don't panic. Read INSTALL 'make test' section instead.
2459
2460=head2 Cygwin intermittent failures of lib/Memoize/t/expire_file 11 and 12
2461
2462The subtests 11 and 12 sometimes fail and sometimes work.
2463
2464=head2 HP-UX lib/io_multihomed Fails When LP64-Configured
2465
2466The lib/io_multihomed test may hang in HP-UX if Perl has been
2467configured to be 64-bit. Because other 64-bit platforms do not hang in
2468this test, HP-UX is suspect. All other tests pass in 64-bit HP-UX. The
2469test attempts to create and connect to "multihomed" sockets (sockets
2470which have multiple IP addresses).
2471
2472=head2 HP-UX lib/posix Subtest 9 Fails When LP64-Configured
2473
2474If perl is configured with -Duse64bitall, the successful result of the
2475subtest 10 of lib/posix may arrive before the successful result of the
2476subtest 9, which confuses the test harness so much that it thinks the
2477subtest 9 failed.
2478
2479=head2 Linux With Sfio Fails op/misc Test 48
2480
2481No known fix.
2482
a0aae13b
JH
2483=head2 Mac OS X
2484
2485The following tests are known to fail:
2486
2487 Failed Test Stat Wstat Total Fail Failed List of Failed
2488 -------------------------------------------------------------------------
2489 ../ext/DB_File/t/db-btree.t 0 11 ?? ?? % ??
2490 ../ext/DB_File/t/db-recno.t 149 3 2.01% 61 63 65
2491 ../ext/POSIX/t/posix.t 31 1 3.23% 10
2492 ../lib/warnings.t 450 1 0.22% 316
2493
f39f21d8
JH
2494=head2 OS/390
2495
2496OS/390 has rather many test failures but the situation is actually
2497better than it was in 5.6.0, it's just that so many new modules and
2498tests have been added.
2499
2500 Failed Test Stat Wstat Total Fail Failed List of Failed
2501 -----------------------------------------------------------------------------
2502 ../ext/B/Deparse.t 14 1 7.14% 14
2503 ../ext/B/Showlex.t 1 1 100.00% 1
2504 ../ext/Encode/Encode/Tcl.t 610 13 2.13% 592 594 596 598
2505 600 602 604-610
2506 ../ext/IO/lib/IO/t/io_unix.t 113 28928 5 3 60.00% 3-5
2507 ../ext/POSIX/POSIX.t 29 1 3.45% 14
2508 ../ext/Storable/t/lock.t 255 65280 5 3 60.00% 3-5
2509 ../lib/locale.t 129 33024 117 19 16.24% 99-117
2510 ../lib/warnings.t 434 1 0.23% 75
2511 ../lib/ExtUtils.t 27 1 3.70% 25
2512 ../lib/Math/BigInt/t/bigintpm.t 1190 1 0.08% 1145
2513 ../lib/Unicode/UCD.t 81 48 59.26% 1-16 49-64 66-81
2514 ../lib/User/pwent.t 9 1 11.11% 4
2515 op/pat.t 660 6 0.91% 242-243 424-425
2516 626-627
2517 op/split.t 0 9 ?? ?? % ??
2518 op/taint.t 174 3 1.72% 156 162 168
2519 op/tr.t 70 3 4.29% 50 58-59
2520 Failed 16/422 test scripts, 96.21% okay. 105/23251 subtests failed, 99.55% okay.
2521
2522=head2 op/sprintf tests 129 and 130
2523
2524The op/sprintf tests 129 and 130 are known to fail on some platforms.
2525Examples include any platform using sfio, and Compaq/Tandem's NonStop-UX.
2526The failing platforms do not comply with the ANSI C Standard, line
252719ff on page 134 of ANSI X3.159 1989 to be exact. (They produce
2528something other than "1" and "-1" when formatting 0.6 and -0.6 using
2529the printf format "%.0f", most often they produce "0" and "-0".)
2530
2531=head2 Failure of Thread tests
2532
fedd8cf1
JH
2533B<Note that support for 5.005-style threading remains experimental
2534and practically unsupported.>
f39f21d8
JH
2535
2536The following tests are known to fail due to fundamental problems in
2537the 5.005 threading implementation. These are not new failures--Perl
25385.005_0x has the same bugs, but didn't have these tests.
2539
fedd8cf1
JH
2540 ext/List/Util/t/first 2
2541 lib/autouse 4
2542 ext/Thread/thr5005 19-20
2543
2544These failures are unlikely to get fixed.
f39f21d8
JH
2545
2546=head2 UNICOS
2547
2548=over 4
2549
2550=item *
2551
2552ext/POSIX/sigaction subtests 6 and 13 may fail.
2553
2554=item *
2555
2556lib/ExtUtils may spuriously claim that subtest 28 failed,
2557which is interesting since the test only has 27 tests.
2558
2559=item *
2560
2561Numerous numerical test failures
2562
2563 op/numconvert 209,210,217,218
2564 op/override 7
2565 ext/Time/HiRes/HiRes 9
2566 lib/Math/BigInt/t/bigintpm 1145
2567 lib/Math/Trig 25
2568
2569These tests fail because of yet unresolved floating point inaccuracies.
2570
2571=back
2572
2573=head2 UTS
2574
2575There are a few known test failures, see L<perluts>.
2576
2577=head2 VMS
2578
00bb525a 2579There is one known test failure with a default configuration:
7207e29d 2580
aecce728 2581 [.run]switches..........................FAILED on test 1
7207e29d 2582
f39f21d8
JH
2583=head2 Win32
2584
2585In multi-CPU boxes there are some problems with the I/O buffering:
2586some output may appear twice.
2587
2588=head2 Localising a Tied Variable Leaks Memory
2589
2590 use Tie::Hash;
2591 tie my %tie_hash => 'Tie::StdHash';
2592
2593 ...
2594
2595 local($tie_hash{Foo}) = 1; # leaks
2596
2597Code like the above is known to leak memory every time the local()
2598is executed.
2599
aecce728
JH
2600=head2 Localising Tied Arrays and Hashes Is Broken
2601
2602 local %tied_array;
2603
2604doesn't work as one would expect: the old value is restored
2605incorrectly.
2606
f39f21d8
JH
2607=head2 Self-tying of Arrays and Hashes Is Forbidden
2608
2609Self-tying of arrays and hashes is broken in rather deep and
2610hard-to-fix ways. As a stop-gap measure to avoid people from getting
2611frustrated at the mysterious results (core dumps, most often) it is
2612for now forbidden (you will get a fatal error even from an attempt).
2613
f39f21d8
JH
2614=head2 Building Extensions Can Fail Because Of Largefiles
2615
2616Some extensions like mod_perl are known to have issues with
2617`largefiles', a change brought by Perl 5.6.0 in which file offsets
2618default to 64 bits wide, where supported. Modules may fail to compile
2619at all or compile and work incorrectly. Currently there is no good
2620solution for the problem, but Configure now provides appropriate
2621non-largefile ccflags, ldflags, libswanted, and libs in the %Config
2622hash (e.g., $Config{ccflags_nolargefiles}) so the extensions that are
2623having problems can try configuring themselves without the
2624largefileness. This is admittedly not a clean solution, and the
2625solution may not even work at all. One potential failure is whether
2626one can (or, if one can, whether it's a good idea) link together at
2627all binaries with different ideas about file offsets, all this is
2628platform-dependent.
2629
aecce728
JH
2630=head2 Unicode Support on EBCDIC Still Spotty
2631
2632Though mostly working, Unicode support still has problem spots on
2633EBCDIC platforms. One such known spot are the C<\p{}> and C<\P{}>
2634regular expression constructs for code points less than 256: the
2635pP are testing for Unicode code points, not knowing about EBCDIC.
2636
f39f21d8
JH
2637=head2 The Compiler Suite Is Still Experimental
2638
44da0e71
JH
2639The compiler suite is slowly getting better but it continues to be
2640highly experimental. Use in production environments is discouraged.
f39f21d8 2641
c4f1ce08 2642=head2 The Long Double Support Is Still Experimental
f39f21d8
JH
2643
2644The ability to configure Perl's numbers to use "long doubles",
2645floating point numbers of hopefully better accuracy, is still
2646experimental. The implementations of long doubles are not yet
2647widespread and the existing implementations are not quite mature
2648or standardised, therefore trying to support them is a rare
2649and moving target. The gain of more precision may also be offset
2650by slowdown in computations (more bits to move around, and the
2651operations are more likely to be executed by less optimised
2652libraries).
33a87e58 2653
c4f1ce08
JH
2654=head2 Seen In Perl 5.7 But Gone Now
2655
c4f1ce08
JH
2656C<Time::Piece> (previously known as C<Time::Object>) was removed
2657because it was felt that it didn't have enough value in it to be a
2658core module. It is still a useful module, though, and is available
2659from the CPAN.
2660
cc0fca54
GS
2661=head1 Reporting Bugs
2662
d4ad863d
JH
2663If you find what you think is a bug, you might check the articles
2664recently posted to the comp.lang.perl.misc newsgroup and the perl
2665bug database at http://bugs.perl.org. There may also be
06a5f41f 2666information at http://www.perl.com/, the Perl Home Page.
cc0fca54
GS
2667
2668If you believe you have an unreported bug, please run the B<perlbug>
2669program included with your release. Be sure to trim your bug down
2670to a tiny but sufficient test case. Your bug report, along with the
d4ad863d 2671output of C<perl -V>, will be sent off to perlbug@perl.org to be
cc0fca54
GS
2672analysed by the Perl porting team.
2673
2674=head1 SEE ALSO
2675
2676The F<Changes> file for exhaustive details on what changed.
2677
2678The F<INSTALL> file for how to build Perl.
2679
2680The F<README> file for general stuff.
2681
2682The F<Artistic> and F<Copying> files for copyright information.
2683
2684=head1 HISTORY
2685
d468ca04 2686Written by Jarkko Hietaniemi <F<jhi@iki.fi>>.
cc0fca54
GS
2687
2688=cut