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ba8251e8 GS |
1 | =head1 NAME |
2 | ||
2bb14304 | 3 | perldelta - what's new for perl5.006 (as of 5.005_56) |
ba8251e8 GS |
4 | |
5 | =head1 DESCRIPTION | |
6 | ||
7 | This document describes differences between the 5.005 release and this one. | |
8 | ||
9 | =head1 Incompatible Changes | |
10 | ||
e02fdbd2 GS |
11 | =head2 Perl Source Incompatibilities |
12 | ||
13 | None known at this time. | |
14 | ||
15 | =head2 C Source Incompatibilities | |
16 | ||
17 | =over 4 | |
18 | ||
19 | =item C<PERL_POLLUTE> | |
20 | ||
21 | Release 5.005 grandfathered old global symbol names by providing preprocessor | |
22 | macros for extension source compatibility. As of release 5.006, these | |
23 | preprocessor definitions are not available by default. You need to explicitly | |
24 | compile perl with C<-DPERL_POLLUTE> in order to get these definitions. | |
25 | ||
86058a2d GS |
26 | =item C<PERL_POLLUTE_MALLOC> |
27 | ||
28 | Enabling the use of Perl's malloc in release 5.005 and earlier caused | |
29 | the namespace of system versions of the malloc family of functions to | |
30 | be usurped by the Perl versions of these functions, since they used the | |
31 | same names by default. | |
32 | ||
33 | Besides causing problems on platforms that do not allow these functions to | |
34 | be cleanly replaced, this also meant that the system versions could not | |
35 | be called in programs that used Perl's malloc. Previous versions of Perl | |
36 | have allowed this behavior to be suppressed with the HIDEMYMALLOC and | |
37 | EMBEDMYMALLOC preprocessor definitions. | |
38 | ||
39 | As of release 5.006, Perl's malloc family of functions have default names | |
40 | distinct from the system versions. You need to explicitly compile perl with | |
41 | C<-DPERL_POLLUTE_MALLOC> in order to get the older behavior. HIDEMYMALLOC | |
42 | and EMBEDMYMALLOC have no effect, since the behavior they enabled is now | |
43 | the default. | |
44 | ||
45 | Note that these functions do B<not> constitute Perl's memory allocation API. | |
46 | See L<perlguts/"Memory Allocation"> for further information about that. | |
47 | ||
e02fdbd2 GS |
48 | =item C<PL_na> and C<dTHR> Issues |
49 | ||
50 | The C<PL_na> global is now thread local, so a C<dTHR> declaration is needed | |
51 | in the scope in which it appears. XSUBs should handle this automatically, | |
52 | but if you have used C<PL_na> in support functions, you either need to | |
53 | change the C<PL_na> to a local variable (which is recommended), or put in | |
54 | a C<dTHR>. | |
55 | ||
56 | =back | |
57 | ||
cceca5ed GS |
58 | =head2 Compatible C Source API Changes |
59 | ||
60 | =over | |
61 | ||
62 | =item C<PATCHLEVEL> is now C<PERL_VERSION> | |
63 | ||
64 | The cpp macros C<PERL_REVISION>, C<PERL_VERSION> and C<PERL_SUBVERSION> | |
65 | are now available by default from perl.h, and reflect the base revision, | |
66 | patchlevel and subversion respectively. C<PERL_REVISION> had no | |
67 | prior equivalent, while C<PERL_VERSION> and C<PERL_SUBVERSION> were | |
68 | previously available as C<PATCHLEVEL> and C<SUBVERSION>. | |
69 | ||
70 | The new names cause less pollution of the cpp namespace, and reflect what | |
71 | the numbers have come to stand for in common practice. For compatibility, | |
72 | the old names are still supported when patchlevel.h is explicitly | |
73 | included (as required before), so there is no source incompatibility | |
74 | due to the change. | |
75 | ||
76 | =back | |
77 | ||
e02fdbd2 GS |
78 | =head2 Binary Incompatibilities |
79 | ||
80 | This release is not binary compatible with the 5.005 release and its | |
81 | maintenance versions. | |
82 | ||
ba8251e8 GS |
83 | =head1 Core Changes |
84 | ||
9d73390d GS |
85 | =head2 Unicode and UTF-8 support |
86 | ||
87 | Perl can optionally use UTF-8 as its internal representation for character | |
88 | strings. The C<use utf8> pragma enables this support in the current lexical | |
89 | scope. See L<utf8> for more information. | |
90 | ||
91 | =head2 Lexically scoped warning categories | |
92 | ||
93 | You can now control the granularity of warnings emitted by perl at a finer | |
94 | level using the C<use warning> pragma. See L<warning> for details. | |
95 | ||
5fdc711f GS |
96 | =head2 Binary numbers supported |
97 | ||
4f19785b WSI |
98 | Binary numbers are now supported as literals, in s?printf formats, and |
99 | C<oct()>: | |
100 | ||
101 | $answer = 0b101010; | |
102 | printf "The answer is: %b\n", oct("0b101010"); | |
103 | ||
5fdc711f GS |
104 | =head2 syswrite() ease-of-use |
105 | ||
6c67e1bb TC |
106 | The length argument of C<syswrite()> is now optional. |
107 | ||
5fdc711f GS |
108 | =head2 64-bit support |
109 | ||
6c67e1bb TC |
110 | Better 64-bit support -- but full support still a distant goal. One |
111 | must Configure with -Duse64bits to get Configure to probe for the | |
112 | extent of 64-bit support. Depending on the platform (hints file) more | |
113 | or less 64-awareness becomes available. As of 5.005_54 at least | |
114 | somewhat 64-bit aware platforms are HP-UX 11 or better, Solaris 2.6 or | |
115 | better, IRIX 6.2 or better. Naturally 64-bit platforms like Digital | |
116 | UNIX and UNICOS also have 64-bit support. | |
e02fdbd2 | 117 | |
62c18ce2 GS |
118 | =head2 Better syntax checks on parenthesized unary operators |
119 | ||
120 | Expressions such as: | |
121 | ||
122 | print defined(&foo,&bar,&baz); | |
123 | print uc("foo","bar","baz"); | |
124 | undef($foo,&bar); | |
125 | ||
7711098a | 126 | used to be accidentally allowed in earlier versions, and produced |
62c18ce2 GS |
127 | unpredictable behavior. Some of them produced ancillary warnings |
128 | when used in this way, while others silently did the wrong thing. | |
129 | ||
130 | The parenthesized forms of most unary operators that expect a single | |
131 | argument will now ensure that they are not called with more than one | |
132 | argument, making the above cases syntax errors. Note that the usual | |
133 | behavior of: | |
134 | ||
135 | print defined &foo, &bar, &baz; | |
136 | print uc "foo", "bar", "baz"; | |
137 | undef $foo, &bar; | |
138 | ||
139 | remains unchanged. See L<perlop>. | |
140 | ||
5a929a98 | 141 | =head2 Improved C<qw//> operator |
8127e0e3 | 142 | |
26ef7447 GS |
143 | The C<qw//> operator is now evaluated at compile time into a true list |
144 | instead of being replaced with a run time call to C<split()>. This | |
145 | removes the confusing behavior of C<qw//> in scalar context stemming from | |
7711098a | 146 | the older implementation, which inherited the behavior from split(). |
26ef7447 GS |
147 | |
148 | Thus: | |
149 | ||
150 | $foo = ($bar) = qw(a b c); print "$foo|$bar\n"; | |
151 | ||
152 | now correctly prints "3|a", instead of "2|a". | |
8127e0e3 | 153 | |
5a929a98 VU |
154 | =head2 pack() format 'Z' supported |
155 | ||
156 | The new format type 'Z' is useful for packing and unpacking null-terminated | |
157 | strings. See L<perlfunc/"pack">. | |
158 | ||
4d0c1c44 | 159 | =head2 pack() format modifier '!' supported |
ee3907e2 | 160 | |
20783b42 | 161 | The new format type modifer '!' is useful for packing and unpacking |
ee3907e2 JH |
162 | native shorts, ints, and longs. See L<perlfunc/"pack">. |
163 | ||
2b92dfce GS |
164 | =head2 $^X variables may now have names longer than one character |
165 | ||
166 | Formerly, $^X was synonymous with ${"\cX"}, but $^XY was a syntax | |
167 | error. Now variable names that begin with a control character may be | |
168 | arbitrarily long. However, for compatibility reasons, these variables | |
169 | I<must> be written with explicit braces, as C<${^XY}> for example. | |
170 | C<${^XYZ}> is synonymous with ${"\cXYZ"}. Variable names with more | |
171 | than one control character, such as C<${^XY^Z}>, are illegal. | |
172 | ||
173 | The old syntax has not changed. As before, the `^X' may either be a | |
174 | literal control-X character or the two character sequence `caret' plus | |
175 | `X'. When the braces are omitted, the variable name stops after the | |
176 | control character. Thus C<"$^XYZ"> continues to be synonymous with | |
7711098a | 177 | C<$^X . "YZ"> as before. |
2b92dfce GS |
178 | |
179 | As before, lexical variables may not have names beginning with control | |
180 | characters. As before, variables whose names begin with a control | |
181 | character are always forced to be in package `main'. These variables | |
182 | are all reserved for future extensions, except the ones that begin | |
183 | with C<^_>, which may be used by user programs and will not acquire a | |
184 | special meaning in any future version of Perl. | |
185 | ||
fbad3eb5 GS |
186 | =head1 Significant bug fixes |
187 | ||
188 | =head2 E<lt>HANDLEE<gt> on empty files | |
189 | ||
190 | With C<$/> set to C<undef>, slurping an empty file returns a string of | |
191 | zero length (instead of C<undef>, as it used to) for the first time the | |
192 | HANDLE is read. Subsequent reads yield C<undef>. | |
193 | ||
194 | This means that the following will append "foo" to an empty file (it used | |
195 | to not do anything before): | |
196 | ||
197 | perl -0777 -pi -e 's/^/foo/' empty_file | |
198 | ||
199 | Note that the behavior of: | |
200 | ||
201 | perl -pi -e 's/^/foo/' empty_file | |
202 | ||
203 | is unchanged (it continues to leave the file empty). | |
204 | ||
0244c3a4 GS |
205 | =head2 C<eval '...'> improvements |
206 | ||
207 | Line numbers (as reflected by caller() and most diagnostics) within | |
208 | C<eval '...'> were often incorrect when here documents were involved. | |
209 | This has been corrected. | |
210 | ||
211 | Lexical lookups for variables appearing in C<eval '...'> within | |
212 | functions that were themselves called within an C<eval '...'> were | |
213 | searching the wrong place for lexicals. They now correctly terminate | |
214 | the lexical search at the subroutine call boundary. | |
215 | ||
216 | Parsing of here documents used to be flawed when they appeared as | |
217 | the replacement expression in C<eval 's/.../.../e'>. This has | |
218 | been fixed. | |
219 | ||
ba8251e8 GS |
220 | =head1 Supported Platforms |
221 | ||
5fdc711f GS |
222 | =over 4 |
223 | ||
224 | =item * | |
225 | ||
6c67e1bb TC |
226 | VM/ESA is now supported. |
227 | ||
5fdc711f GS |
228 | =item * |
229 | ||
ee3907e2 JH |
230 | Siemens BS2000 is now supported under the POSIX Shell. |
231 | ||
232 | =item * | |
233 | ||
2bb14304 JH |
234 | The Mach CThreads (NEXTSTEP, OPENSTEP) are now supported by the Thread |
235 | extension. | |
6c67e1bb | 236 | |
5fdc711f GS |
237 | =item * |
238 | ||
ee3907e2 | 239 | GNU/Hurd is now supported. |
6c67e1bb | 240 | |
00ad96e1 JH |
241 | =item * |
242 | ||
243 | Rhapsody is now supported. | |
244 | ||
5fdc711f GS |
245 | =back |
246 | ||
6c67e1bb TC |
247 | =head1 New tests |
248 | ||
249 | =over 4 | |
250 | ||
251 | =item op/io_const | |
252 | ||
253 | IO constants (SEEK_*, _IO*). | |
254 | ||
255 | =item op/io_dir | |
256 | ||
257 | Directory-related IO methods (new, read, close, rewind, tied delete). | |
258 | ||
259 | =item op/io_multihomed | |
260 | ||
261 | INET sockets with multi-homed hosts. | |
262 | ||
263 | =item op/io_poll | |
264 | ||
265 | IO poll(). | |
266 | ||
267 | =item op/io_unix | |
268 | ||
269 | UNIX sockets. | |
270 | ||
271 | =item op/filetest | |
272 | ||
273 | File test operators. | |
274 | ||
275 | =item op/lex_assign | |
276 | ||
5fdc711f | 277 | Verify operations that access pad objects (lexicals and temporaries). |
6c67e1bb TC |
278 | |
279 | =back | |
e02fdbd2 | 280 | |
ba8251e8 GS |
281 | =head1 Modules and Pragmata |
282 | ||
3e8c4fa0 JH |
283 | =head2 Modules |
284 | ||
b7d8191e JH |
285 | =over 4 |
286 | ||
287 | =item Dumpvalue | |
288 | ||
289 | Added Dumpvalue module provides screen dumps of Perl data. | |
290 | ||
291 | =item Benchmark | |
292 | ||
868cb350 | 293 | You can now run tests for I<n> seconds instead of guessing the right |
155776c0 JH |
294 | number of tests to run: e.g. timethese(-5, ...) will run each of the |
295 | codes for at least 5 CPU seconds. Zero as the "number of repetitions" | |
296 | means "for at least 3 CPU seconds". The output format has also | |
297 | changed. For example: | |
298 | ||
299 | use Benchmark;$x=3;timethese(-5,{a=>sub{$x*$x},b=>sub{$x**2}}) | |
300 | ||
301 | will now output something like this: | |
302 | ||
303 | Benchmark: running a, b, each for at least 5 CPU seconds... | |
304 | a: 5 wallclock secs ( 5.77 usr + 0.00 sys = 5.77 CPU) @ 200551.91/s (n=1156516) | |
305 | b: 4 wallclock secs ( 5.00 usr + 0.02 sys = 5.02 CPU) @ 159605.18/s (n=800686) | |
306 | ||
307 | New features: "each for at least N CPU seconds...", "wallclock secs", | |
308 | and the "@ operations/CPU second (n=operations)". | |
b7d8191e | 309 | |
f505c983 GS |
310 | =item Devel::Peek |
311 | ||
312 | The Devel::Peek module provides access to the internal representation | |
313 | of Perl variables. It is a data debugging tool for the XS programmer. | |
314 | ||
b7d8191e JH |
315 | =item Fcntl |
316 | ||
317 | More Fcntl constants added: F_SETLK64, F_SETLKW64, O_LARGEFILE for | |
318 | large (more than 4G) file access (the 64-bit support is not yet | |
319 | working, though, so no need to get overly excited), Free/Net/OpenBSD | |
320 | locking behaviour flags F_FLOCK, F_POSIX, Linux F_SHLCK, and | |
321 | O_ACCMODE: the mask of O_RDONLY, O_WRONLY, and O_RDWR. | |
322 | ||
f505c983 GS |
323 | =item File::Spec |
324 | ||
325 | New methods have been added to the File::Spec module: devnull() returns | |
326 | the name of the null device (/dev/null on UNIX) and tmpdir() the name of | |
327 | the temp directory (normally /tmp on UNIX). There are now also methods | |
328 | to convert between absolute and relative filenames: abs2rel() and | |
329 | rel2abs(). For compatibility with operating systems that specify volume | |
330 | names in file paths, the splitpath(), splitdir() and catdir() methods | |
331 | have been added. | |
332 | ||
333 | =item File::Spec::Functions | |
334 | ||
335 | The new File::Spec::Functions modules provides a function interface | |
336 | to the File::Spec module. Allows shorthand | |
337 | ||
338 | $fullname = catfile($dir1, $dir2, $file); | |
339 | ||
340 | instead of | |
341 | ||
342 | $fullname = File::Spec->catfile($dir1, $dir2, $file); | |
343 | ||
b7d8191e | 344 | =item Math::Complex |
7711098a | 345 | |
868cb350 JH |
346 | The accessor methods Re, Im, arg, abs, rho, and theta, can now also |
347 | act as mutators (accessor $z->Re(), mutator $z->Re(3)). | |
b7d8191e JH |
348 | |
349 | =item Math::Trig | |
350 | ||
351 | A little bit of radial trigonometry (cylindrical and spherical) added, | |
868cb350 | 352 | radial coordinate conversions and the great circle distance. |
b7d8191e | 353 | |
06ef4121 PC |
354 | =item Time::Local |
355 | ||
356 | The timelocal() and timegm() functions used to silently return bogus | |
357 | results when the date exceeded the machine's integer range. They | |
358 | consistently croak() if the date falls in an unsupported range. | |
359 | ||
8fe0a5c4 JD |
360 | =item Win32 |
361 | ||
362 | The error return value in list context has been changed for all functions | |
363 | that return a list of values. Previously these functions returned a list | |
364 | with a single element C<undef> in case an error occurred. Now these functions | |
365 | return the empty list in these situations. This applies to the following | |
366 | functions: | |
367 | ||
368 | Win32::FsType | |
369 | Win32::GetOSVersion | |
370 | ||
371 | The remaining functions are unchanged and continue to return C<undef> on | |
372 | error even in list context. | |
373 | ||
374 | The Win32::SetLastError(ERROR) function has been added as a complement | |
375 | to the Win32::GetLastError() function. | |
376 | ||
377 | The new Win32::GetFullPathName(FILENAME) returns the full absolute | |
378 | pathname for FILENAME in scalar context. In list context it returns | |
379 | a two element list containing the fully qualified directory name and | |
380 | the filename. | |
381 | ||
b7d8191e | 382 | =back |
3e8c4fa0 JH |
383 | |
384 | =head2 Pragmata | |
385 | ||
9d73390d GS |
386 | C<use utf8;>, to enable UTF-8 and Unicode support. |
387 | ||
388 | Lexical warnings pragma, C<use warning;>, to control optional warnings. | |
6c67e1bb | 389 | |
9d73390d | 390 | C<use filetest;>, to control the behaviour of filetests (C<-r> C<-w> ...). |
6c67e1bb TC |
391 | Currently only one subpragma implemented, "use filetest 'access';", |
392 | that enables the use of access(2) or equivalent to check the | |
393 | permissions instead of using stat(2) as usual. This matters | |
394 | in filesystems where there are ACLs (access control lists), the | |
395 | stat(2) might lie, while access(2) knows better. | |
396 | ||
ba8251e8 GS |
397 | =head1 Utility Changes |
398 | ||
e02fdbd2 GS |
399 | Todo. |
400 | ||
ba8251e8 GS |
401 | =head1 Documentation Changes |
402 | ||
5fdc711f GS |
403 | =over 4 |
404 | ||
405 | =item perlopentut.pod | |
f8284313 | 406 | |
5fdc711f GS |
407 | A tutorial on using open() effectively. |
408 | ||
409 | =item perlreftut.pod | |
410 | ||
411 | A tutorial that introduces the essentials of references. | |
412 | ||
413 | =back | |
e02fdbd2 | 414 | |
ba8251e8 GS |
415 | =head1 New Diagnostics |
416 | ||
6b121555 JH |
417 | =item /%s/: Unrecognized escape \\%c passed through |
418 | ||
419 | (W) You used a backslash-character combination which is not recognized | |
7711098a | 420 | by Perl. This combination appears in an interpolated variable or a |
6b121555 JH |
421 | C<'>-delimited regular expression. |
422 | ||
423 | =item Unrecognized escape \\%c passed through | |
424 | ||
425 | (W) You used a backslash-character combination which is not recognized | |
426 | by Perl. | |
e02fdbd2 | 427 | |
06eaf0bc GS |
428 | =item Missing command in piped open |
429 | ||
430 | (W) You used the C<open(FH, "| command")> or C<open(FH, "command |")> | |
431 | construction, but the command was missing or blank. | |
432 | ||
ba8251e8 GS |
433 | =head1 Obsolete Diagnostics |
434 | ||
e02fdbd2 GS |
435 | Todo. |
436 | ||
04d420f9 JH |
437 | =head1 Configuration Changes |
438 | ||
439 | You can use "Configure -Uinstallusrbinperl" which causes installperl | |
440 | to skip installing perl also as /usr/bin/perl. This is useful if you | |
441 | prefer not to modify /usr/bin for some reason or another but harmful | |
442 | because many scripts assume to find Perl in /usr/bin/perl. | |
443 | ||
ba8251e8 GS |
444 | =head1 BUGS |
445 | ||
446 | If you find what you think is a bug, you might check the headers of | |
447 | recently posted articles in the comp.lang.perl.misc newsgroup. | |
448 | There may also be information at http://www.perl.com/perl/, the Perl | |
449 | Home Page. | |
450 | ||
451 | If you believe you have an unreported bug, please run the B<perlbug> | |
452 | program included with your release. Make sure you trim your bug down | |
453 | to a tiny but sufficient test case. Your bug report, along with the | |
454 | output of C<perl -V>, will be sent off to <F<perlbug@perl.com>> to be | |
455 | analysed by the Perl porting team. | |
456 | ||
457 | =head1 SEE ALSO | |
458 | ||
459 | The F<Changes> file for exhaustive details on what changed. | |
460 | ||
461 | The F<INSTALL> file for how to build Perl. | |
462 | ||
463 | The F<README> file for general stuff. | |
464 | ||
465 | The F<Artistic> and F<Copying> files for copyright information. | |
466 | ||
467 | =head1 HISTORY | |
468 | ||
469 | Written by Gurusamy Sarathy <F<gsar@umich.edu>>, with many contributions | |
470 | from The Perl Porters. | |
471 | ||
472 | Send omissions or corrections to <F<perlbug@perl.com>>. | |
473 | ||
474 | =cut |