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1 | =head1 NAME |
2 | |
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3 | perldelta - what's new for perl v5.6 (as of v5.005_61) |
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4 | |
5 | =head1 DESCRIPTION |
6 | |
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7 | This is an unsupported alpha release, meant for intrepid Perl developers |
8 | only. The included sources may not even build correctly on some platforms. |
9 | Subscribing to perl5-porters is the best way to monitor and contribute |
10 | to the progress of development releases (see www.perl.org for info). |
11 | |
ba8251e8 |
12 | This document describes differences between the 5.005 release and this one. |
13 | |
14 | =head1 Incompatible Changes |
15 | |
e02fdbd2 |
16 | =head2 Perl Source Incompatibilities |
17 | |
f29c64d6 |
18 | TODO |
e02fdbd2 |
19 | |
20 | =head2 C Source Incompatibilities |
21 | |
22 | =over 4 |
23 | |
24 | =item C<PERL_POLLUTE> |
25 | |
26 | Release 5.005 grandfathered old global symbol names by providing preprocessor |
87275199 |
27 | macros for extension source compatibility. As of release 5.6, these |
e02fdbd2 |
28 | preprocessor definitions are not available by default. You need to explicitly |
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29 | compile perl with C<-DPERL_POLLUTE> to get these definitions. For |
30 | extensions still using the old symbols, this option can be |
2aea4d40 |
31 | specified via MakeMaker: |
32 | |
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33 | perl Makefile.PL POLLUTE=1 |
e02fdbd2 |
34 | |
f29c64d6 |
35 | =item C<PERL_IMPLICIT_CONTEXT> |
36 | |
37 | This new build option provides a set of macros for all API functions |
38 | such that an implicit interpreter/thread context argument is passed to |
39 | every API function. As a result of this, something like C<sv_setsv(foo,bar)> |
2c2d71f5 |
40 | amounts to a macro invocation that actually translates to something like |
f29c64d6 |
41 | C<Perl_sv_setsv(my_perl,foo,bar)>. While this is generally expected |
42 | to not have any significant source compatibility issues, the difference |
43 | between a macro and a real function call will need to be considered. |
44 | |
2c2d71f5 |
45 | This means that there B<is> a source compatibility issue as a result of |
46 | this if your extensions attempt to use pointers to any of the Perl API |
47 | functions. |
48 | |
f29c64d6 |
49 | Note that the above issue is not relevant to the default build of |
50 | Perl, whose interfaces continue to match those of prior versions |
51 | (but subject to the other options described here). |
52 | |
651a3225 |
53 | PERL_IMPLICIT_CONTEXT is automatically enabled whenever Perl is built |
54 | with one of -Dusethreads, -Dusemultiplicity, or both. |
f29c64d6 |
55 | |
2c2d71f5 |
56 | See L<perlguts/"The Perl API"> for detailed information on the |
57 | ramifications of building Perl using this option. |
58 | |
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59 | =item C<PERL_POLLUTE_MALLOC> |
60 | |
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61 | Enabling Perl's malloc in release 5.005 and earlier caused |
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62 | the namespace of system versions of the malloc family of functions to |
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63 | be usurped by the Perl versions, since by default they used the |
64 | same names. |
86058a2d |
65 | |
66 | Besides causing problems on platforms that do not allow these functions to |
67 | be cleanly replaced, this also meant that the system versions could not |
68 | be called in programs that used Perl's malloc. Previous versions of Perl |
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69 | have allowed this behaviour to be suppressed with the HIDEMYMALLOC and |
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70 | EMBEDMYMALLOC preprocessor definitions. |
71 | |
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72 | As of release 5.6, Perl's malloc family of functions have default names |
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73 | distinct from the system versions. You need to explicitly compile perl with |
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74 | C<-DPERL_POLLUTE_MALLOC> to get the older behaviour. HIDEMYMALLOC |
75 | and EMBEDMYMALLOC have no effect, since the behaviour they enabled is now |
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76 | the default. |
77 | |
78 | Note that these functions do B<not> constitute Perl's memory allocation API. |
79 | See L<perlguts/"Memory Allocation"> for further information about that. |
80 | |
e02fdbd2 |
81 | =item C<PL_na> and C<dTHR> Issues |
82 | |
83 | The C<PL_na> global is now thread local, so a C<dTHR> declaration is needed |
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84 | in the scope in which the global appears. XSUBs should handle this automatically, |
e02fdbd2 |
85 | but if you have used C<PL_na> in support functions, you either need to |
86 | change the C<PL_na> to a local variable (which is recommended), or put in |
87 | a C<dTHR>. |
88 | |
89 | =back |
90 | |
cceca5ed |
91 | =head2 Compatible C Source API Changes |
92 | |
93 | =over |
94 | |
95 | =item C<PATCHLEVEL> is now C<PERL_VERSION> |
96 | |
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97 | The cpp macros C<PERL_REVISION>, C<PERL_VERSION>, and C<PERL_SUBVERSION> |
cceca5ed |
98 | are now available by default from perl.h, and reflect the base revision, |
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99 | patchlevel, and subversion respectively. C<PERL_REVISION> had no |
cceca5ed |
100 | prior equivalent, while C<PERL_VERSION> and C<PERL_SUBVERSION> were |
101 | previously available as C<PATCHLEVEL> and C<SUBVERSION>. |
102 | |
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103 | The new names cause less pollution of the B<cpp> namespace and reflect what |
cceca5ed |
104 | the numbers have come to stand for in common practice. For compatibility, |
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105 | the old names are still supported when F<patchlevel.h> is explicitly |
cceca5ed |
106 | included (as required before), so there is no source incompatibility |
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107 | from the change. |
cceca5ed |
108 | |
109 | =back |
110 | |
e02fdbd2 |
111 | =head2 Binary Incompatibilities |
112 | |
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113 | The default build of this release is binary compatible with the 5.005 |
114 | release or its maintenance versions. |
f29c64d6 |
115 | |
116 | The usethreads or usemultiplicity builds are B<not> binary compatible |
117 | with the corresponding builds in 5.005. |
e02fdbd2 |
118 | |
ba8251e8 |
119 | =head1 Core Changes |
120 | |
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121 | =head2 Unicode and UTF-8 support |
122 | |
123 | Perl can optionally use UTF-8 as its internal representation for character |
124 | strings. The C<use utf8> pragma enables this support in the current lexical |
125 | scope. See L<utf8> for more information. |
126 | |
127 | =head2 Lexically scoped warning categories |
128 | |
129 | You can now control the granularity of warnings emitted by perl at a finer |
4438c4b7 |
130 | level using the C<use warnings> pragma. See L<warnings> and L<perllexwarn> |
0453d815 |
131 | for details. |
9d73390d |
132 | |
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133 | =head2 Binary numbers supported |
134 | |
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135 | Binary numbers are now supported as literals, in s?printf formats, and |
136 | C<oct()>: |
137 | |
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138 | $answer = 0b101010; |
139 | printf "The answer is: %b\n", oct("0b101010"); |
4f19785b |
140 | |
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141 | =head2 syswrite() ease-of-use |
142 | |
6c67e1bb |
143 | The length argument of C<syswrite()> is now optional. |
144 | |
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145 | =head2 64-bit support |
146 | |
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147 | All platforms that have 64-bit integers either (a) natively as longs |
148 | or ints (b) via special compiler flags (c) using long long are able to |
149 | use "quads" (64-integers) as follows: |
150 | |
151 | =over 4 |
152 | |
153 | =item constants in the code |
154 | |
155 | =item arguments to oct() and hex() |
156 | |
157 | =item arguments to print(), printf() and sprintf() |
158 | |
159 | =item pack() and unpack() "q" format |
160 | |
161 | =item in basic arithmetics |
162 | |
c5a0f51a |
163 | =item vec() (but see the below note about bit arithmetics) |
164 | |
9c107f78 |
165 | =back |
166 | |
167 | Note that unless you have the case (a) you will have to configure |
168 | and compile Perl using the -Duse64bits Configure flag. |
169 | |
c5a0f51a |
170 | Unfortunately bit arithmetics (&, |, ^, ~, <<, >>) are not 64-bit clean. |
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171 | |
2d4389e4 |
172 | Last but not least: note that due to Perl's habit of always using |
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173 | floating point numbers the quads are still not true integers. |
174 | When quads overflow their limits (0...18_446_744_073_709_551_615 unsigned, |
175 | -9_223_372_036_854_775_808...9_223_372_036_854_775_807 signed), they |
176 | are silently promoted to floating point numbers, after which they will |
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177 | start losing precision (their lower digits). |
178 | |
179 | =head2 Large file support |
180 | |
181 | If you have filesystems that support "large files" (files larger than |
182 | 2 gigabytes), you may now also be able to create and access them from Perl. |
183 | |
184 | Note that in addition to requiring a proper file system to do this you |
185 | may also need to adjust your per-process (or even your per-system) |
186 | maximum filesize limits before running Perl scripts that try to handle |
187 | large files, especially if you intend to write such files. |
188 | |
189 | Adjusting your file system/system limits is outside the scope of Perl. |
190 | For process limits, you may try to increase the limits using your |
191 | shell's limit/ulimit command before running Perl. The BSD::Resource |
192 | extension (not included with the standard Perl distribution) may also |
193 | be of use. |
194 | |
195 | (Large file support is also related to 64-bit support, for obvious reasons) |
09bef843 |
196 | |
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197 | =head2 Better syntax checks on parenthesized unary operators |
198 | |
199 | Expressions such as: |
200 | |
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201 | print defined(&foo,&bar,&baz); |
202 | print uc("foo","bar","baz"); |
203 | undef($foo,&bar); |
62c18ce2 |
204 | |
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205 | used to be accidentally allowed in earlier versions, and produced |
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206 | unpredictable behaviour. Some produced ancillary warnings |
207 | when used in this way; others silently did the wrong thing. |
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208 | |
209 | The parenthesized forms of most unary operators that expect a single |
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210 | argument now ensure that they are not called with more than one |
211 | argument, making the cases shown above syntax errors. The usual |
212 | behaviour of: |
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213 | |
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214 | print defined &foo, &bar, &baz; |
215 | print uc "foo", "bar", "baz"; |
216 | undef $foo, &bar; |
62c18ce2 |
217 | |
218 | remains unchanged. See L<perlop>. |
219 | |
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220 | =head2 POSIX character class syntax [: :] supported |
221 | |
222 | For example to match alphabetic characters use /[[:alpha:]]/. |
223 | See L<perlre> for details. |
224 | |
5a929a98 |
225 | =head2 Improved C<qw//> operator |
8127e0e3 |
226 | |
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227 | The C<qw//> operator is now evaluated at compile time into a true list |
228 | instead of being replaced with a run time call to C<split()>. This |
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229 | removes the confusing misbehaviour of C<qw//> in scalar context, which |
230 | had inherited that behaviour from split(). |
26ef7447 |
231 | |
232 | Thus: |
233 | |
234 | $foo = ($bar) = qw(a b c); print "$foo|$bar\n"; |
235 | |
236 | now correctly prints "3|a", instead of "2|a". |
8127e0e3 |
237 | |
5a929a98 |
238 | =head2 pack() format 'Z' supported |
239 | |
240 | The new format type 'Z' is useful for packing and unpacking null-terminated |
241 | strings. See L<perlfunc/"pack">. |
242 | |
4d0c1c44 |
243 | =head2 pack() format modifier '!' supported |
ee3907e2 |
244 | |
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245 | The new format type modifier '!' is useful for packing and unpacking |
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246 | native shorts, ints, and longs. See L<perlfunc/"pack">. |
247 | |
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248 | =head2 pack() and unpack() support counted strings |
249 | |
250 | The template character '#' can be used to specify a counted string |
251 | type to be packed or unpacked. See L<perlfunc/"pack">. |
252 | |
2b92dfce |
253 | =head2 $^X variables may now have names longer than one character |
254 | |
255 | Formerly, $^X was synonymous with ${"\cX"}, but $^XY was a syntax |
256 | error. Now variable names that begin with a control character may be |
257 | arbitrarily long. However, for compatibility reasons, these variables |
258 | I<must> be written with explicit braces, as C<${^XY}> for example. |
14218588 |
259 | C<${^XYZ}> is synonymous with ${"\cXYZ"}. Variable names with more |
2b92dfce |
260 | than one control character, such as C<${^XY^Z}>, are illegal. |
261 | |
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262 | The old syntax has not changed. As before, `^X' may be either a |
263 | literal control-X character or the two-character sequence `caret' plus |
264 | `X'. When braces are omitted, the variable name stops after the |
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265 | control character. Thus C<"$^XYZ"> continues to be synonymous with |
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266 | C<$^X . "YZ"> as before. |
2b92dfce |
267 | |
268 | As before, lexical variables may not have names beginning with control |
269 | characters. As before, variables whose names begin with a control |
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270 | character are always forced to be in package `main'. All such variables |
271 | are reserved for future extensions, except those that begin with |
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272 | C<^_>, which may be used by user programs and are guaranteed not to |
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273 | acquire special meaning in any future version of Perl. |
2b92dfce |
274 | |
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275 | =head2 C<use attrs> implicit in subroutine attributes |
276 | |
277 | Formerly, if you wanted to mark a subroutine as being a method call or |
278 | as requiring an automatic lock() when it is entered, you had to declare |
279 | that with a C<use attrs> pragma in the body of the subroutine. |
280 | That can now be accomplished with a declaration syntax, like this: |
281 | |
282 | sub mymethod : locked, method ; |
283 | ... |
284 | sub mymethod : locked, method { |
285 | ... |
286 | } |
287 | |
288 | F<AutoSplit.pm> and F<SelfLoader.pm> have been updated to keep the attributes |
289 | with the stubs they provide. See L<attributes>. |
290 | |
fbad3eb5 |
291 | =head1 Significant bug fixes |
292 | |
293 | =head2 E<lt>HANDLEE<gt> on empty files |
294 | |
295 | With C<$/> set to C<undef>, slurping an empty file returns a string of |
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296 | zero length (instead of C<undef>, as it used to) the first time the |
297 | HANDLE is read. Further reads yield C<undef>. |
fbad3eb5 |
298 | |
299 | This means that the following will append "foo" to an empty file (it used |
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300 | to do nothing): |
fbad3eb5 |
301 | |
302 | perl -0777 -pi -e 's/^/foo/' empty_file |
303 | |
14218588 |
304 | The behaviour of: |
fbad3eb5 |
305 | |
306 | perl -pi -e 's/^/foo/' empty_file |
307 | |
308 | is unchanged (it continues to leave the file empty). |
309 | |
0244c3a4 |
310 | =head2 C<eval '...'> improvements |
311 | |
312 | Line numbers (as reflected by caller() and most diagnostics) within |
313 | C<eval '...'> were often incorrect when here documents were involved. |
314 | This has been corrected. |
315 | |
316 | Lexical lookups for variables appearing in C<eval '...'> within |
317 | functions that were themselves called within an C<eval '...'> were |
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318 | searching the wrong place for lexicals. The lexical search now |
319 | correctly ends at the subroutine's block boundary. |
0244c3a4 |
320 | |
321 | Parsing of here documents used to be flawed when they appeared as |
322 | the replacement expression in C<eval 's/.../.../e'>. This has |
323 | been fixed. |
324 | |
45bc9206 |
325 | =head2 Automatic flushing of output buffers |
326 | |
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327 | fork(), exec(), system(), qx//, and pipe open()s now flush buffers |
328 | of all files opened for output when the operation |
329 | was attempted. This mostly eliminates confusing |
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330 | buffering mishaps suffered by users unaware of how Perl internally |
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331 | handles I/O. |
45bc9206 |
332 | |
af8c498a |
333 | =head2 Better diagnostics on meaningless filehandle operations |
334 | |
335 | Constructs such as C<open(E<lt>FHE<gt>)> and C<close(E<lt>FHE<gt>)> |
336 | are compile time errors. Attempting to read from filehandles that |
337 | were opened only for writing will now produce warnings (just as |
338 | writing to read-only filehandles does). |
339 | |
54195c32 |
340 | =head2 Buffered data discarded from input filehandle when dup'ed. |
341 | |
342 | C<open(NEW, "E<lt>&OLD")> now discards any data that was previously |
343 | read and buffered in C<OLD>. The next read operation on C<NEW> will |
344 | return the same data as the corresponding operation on C<OLD>. |
345 | Formerly, it would have returned the data from the start of the |
346 | following disk block instead. |
347 | |
ba8251e8 |
348 | =head1 Supported Platforms |
349 | |
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350 | =over 4 |
351 | |
352 | =item * |
353 | |
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354 | VM/ESA is now supported. |
355 | |
5fdc711f |
356 | =item * |
357 | |
ee3907e2 |
358 | Siemens BS2000 is now supported under the POSIX Shell. |
359 | |
360 | =item * |
361 | |
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362 | The Mach CThreads (NEXTSTEP, OPENSTEP) are now supported by the Thread |
363 | extension. |
6c67e1bb |
364 | |
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365 | =item * |
366 | |
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367 | GNU/Hurd is now supported. |
6c67e1bb |
368 | |
00ad96e1 |
369 | =item * |
370 | |
371 | Rhapsody is now supported. |
372 | |
27806c82 |
373 | =item * |
374 | |
375 | EPOC is is now supported (on Psion 5). |
376 | |
5fdc711f |
377 | =back |
378 | |
6c67e1bb |
379 | =head1 New tests |
380 | |
381 | =over 4 |
382 | |
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383 | =item lib/attrs |
384 | |
385 | Compatibility tests for C<sub : attrs> vs the older C<use attrs>. |
386 | |
387 | =item lib/io_const |
6c67e1bb |
388 | |
389 | IO constants (SEEK_*, _IO*). |
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390 | |
09bef843 |
391 | =item lib/io_dir |
6c67e1bb |
392 | |
393 | Directory-related IO methods (new, read, close, rewind, tied delete). |
394 | |
09bef843 |
395 | =item lib/io_multihomed |
6c67e1bb |
396 | |
397 | INET sockets with multi-homed hosts. |
398 | |
09bef843 |
399 | =item lib/io_poll |
6c67e1bb |
400 | |
401 | IO poll(). |
402 | |
09bef843 |
403 | =item lib/io_unix |
6c67e1bb |
404 | |
405 | UNIX sockets. |
406 | |
09bef843 |
407 | =item op/attrs |
408 | |
409 | Regression tests for C<my ($x,@y,%z) : attrs> and <sub : attrs>. |
410 | |
6c67e1bb |
411 | =item op/filetest |
412 | |
413 | File test operators. |
414 | |
415 | =item op/lex_assign |
416 | |
5fdc711f |
417 | Verify operations that access pad objects (lexicals and temporaries). |
6c67e1bb |
418 | |
419 | =back |
e02fdbd2 |
420 | |
ba8251e8 |
421 | =head1 Modules and Pragmata |
422 | |
3e8c4fa0 |
423 | =head2 Modules |
424 | |
b7d8191e |
425 | =over 4 |
426 | |
09bef843 |
427 | =item attributes |
428 | |
429 | While used internally by Perl as a pragma, this module also |
430 | provides a way to fetch subroutine and variable attributes. |
431 | See L<attributes>. |
432 | |
f29c64d6 |
433 | =item ByteLoader |
434 | |
435 | The ByteLoader is a dedication extension to generate and run |
436 | Perl bytecode. See L<ByteLoader>. |
437 | |
438 | =item B |
439 | |
440 | The Perl Compiler suite has been extensively reworked for this |
441 | release. |
442 | |
443 | =item Devel::DProf |
444 | |
445 | Devel::DProf, a Perl source code profiler has been added. |
446 | |
b7d8191e |
447 | =item Dumpvalue |
448 | |
449 | Added Dumpvalue module provides screen dumps of Perl data. |
450 | |
451 | =item Benchmark |
452 | |
868cb350 |
453 | You can now run tests for I<n> seconds instead of guessing the right |
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454 | number of tests to run: e.g. timethese(-5, ...) will run each |
455 | code for at least 5 CPU seconds. Zero as the "number of repetitions" |
155776c0 |
456 | means "for at least 3 CPU seconds". The output format has also |
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457 | changed. For example: |
155776c0 |
458 | |
459 | use Benchmark;$x=3;timethese(-5,{a=>sub{$x*$x},b=>sub{$x**2}}) |
460 | |
461 | will now output something like this: |
462 | |
463 | Benchmark: running a, b, each for at least 5 CPU seconds... |
464 | a: 5 wallclock secs ( 5.77 usr + 0.00 sys = 5.77 CPU) @ 200551.91/s (n=1156516) |
465 | b: 4 wallclock secs ( 5.00 usr + 0.02 sys = 5.02 CPU) @ 159605.18/s (n=800686) |
466 | |
467 | New features: "each for at least N CPU seconds...", "wallclock secs", |
468 | and the "@ operations/CPU second (n=operations)". |
b7d8191e |
469 | |
f505c983 |
470 | =item Devel::Peek |
471 | |
472 | The Devel::Peek module provides access to the internal representation |
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473 | of Perl variables and data. It is a data debugging tool for the XS programmer. |
f505c983 |
474 | |
b7d8191e |
475 | =item Fcntl |
476 | |
477 | More Fcntl constants added: F_SETLK64, F_SETLKW64, O_LARGEFILE for |
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478 | large (more than 4G) file access (64-bit support is not yet |
b7d8191e |
479 | working, though, so no need to get overly excited), Free/Net/OpenBSD |
480 | locking behaviour flags F_FLOCK, F_POSIX, Linux F_SHLCK, and |
481 | O_ACCMODE: the mask of O_RDONLY, O_WRONLY, and O_RDWR. |
482 | |
f505c983 |
483 | =item File::Spec |
484 | |
485 | New methods have been added to the File::Spec module: devnull() returns |
19799a22 |
486 | the name of the null device (/dev/null on Unix) and tmpdir() the name of |
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487 | the temp directory (normally /tmp on Unix). There are now also methods |
f505c983 |
488 | to convert between absolute and relative filenames: abs2rel() and |
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489 | rel2abs(). For compatibility with operating systems that specify volume |
490 | names in file paths, the splitpath(), splitdir(), and catdir() methods |
f505c983 |
491 | have been added. |
492 | |
493 | =item File::Spec::Functions |
494 | |
495 | The new File::Spec::Functions modules provides a function interface |
14218588 |
496 | to the File::Spec module. Allows shorthand |
f505c983 |
497 | |
14218588 |
498 | $fullname = catfile($dir1, $dir2, $file); |
f505c983 |
499 | |
500 | instead of |
501 | |
14218588 |
502 | $fullname = File::Spec->catfile($dir1, $dir2, $file); |
f505c983 |
503 | |
e16b8f49 |
504 | =item Math::BigInt |
505 | |
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506 | The logical operations C<E<lt>E<lt>>, C<E<gt>E<gt>>, C<&>, C<|>, |
e16b8f49 |
507 | and C<~> are now supported on bigints. |
508 | |
b7d8191e |
509 | =item Math::Complex |
7711098a |
510 | |
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511 | The accessor methods Re, Im, arg, abs, rho, and theta can now also |
868cb350 |
512 | act as mutators (accessor $z->Re(), mutator $z->Re(3)). |
b7d8191e |
513 | |
514 | =item Math::Trig |
515 | |
14218588 |
516 | A little bit of radial trigonometry (cylindrical and spherical), |
517 | radial coordinate conversions, and the great circle distance were added. |
b7d8191e |
518 | |
f4b9d880 |
519 | =item SDBM_File |
520 | |
521 | An EXISTS method has been added to this module (and sdbm_exists() has |
522 | been added to the underlying sdbm library), so one can now call exists |
14218588 |
523 | on an SDBM_File tied hash and get the correct result, rather than a |
f4b9d880 |
524 | runtime error. |
525 | |
06ef4121 |
526 | =item Time::Local |
527 | |
528 | The timelocal() and timegm() functions used to silently return bogus |
529 | results when the date exceeded the machine's integer range. They |
14218588 |
530 | now consistently croak() if the date falls in an unsupported range. |
06ef4121 |
531 | |
8fe0a5c4 |
532 | =item Win32 |
533 | |
534 | The error return value in list context has been changed for all functions |
14218588 |
535 | that return a list of values. Previously these functions returned a list |
536 | with a single element C<undef> if an error occurred. Now these functions |
537 | return the empty list in these situations. This applies to the following |
8fe0a5c4 |
538 | functions: |
539 | |
14218588 |
540 | Win32::FsType |
541 | Win32::GetOSVersion |
8fe0a5c4 |
542 | |
543 | The remaining functions are unchanged and continue to return C<undef> on |
544 | error even in list context. |
545 | |
546 | The Win32::SetLastError(ERROR) function has been added as a complement |
547 | to the Win32::GetLastError() function. |
548 | |
549 | The new Win32::GetFullPathName(FILENAME) returns the full absolute |
14218588 |
550 | pathname for FILENAME in scalar context. In list context it returns |
551 | a two-element list containing the fully qualified directory name and |
8fe0a5c4 |
552 | the filename. |
553 | |
9fe6733a |
554 | =item DBM Filters |
555 | |
556 | A new feature called "DBM Filters" has been added to all the |
14218588 |
557 | DBM modules--DB_File, GDBM_File, NDBM_File, ODBM_File, and SDBM_File. |
558 | DBM Filters add four new methods to each DBM module: |
9fe6733a |
559 | |
560 | filter_store_key |
561 | filter_store_value |
562 | filter_fetch_key |
563 | filter_fetch_value |
564 | |
14218588 |
565 | These can be used to filter key-value pairs before the pairs are |
9fe6733a |
566 | written to the database or just after they are read from the database. |
567 | See L<perldbmfilter> for further information. |
568 | |
b7d8191e |
569 | =back |
3e8c4fa0 |
570 | |
571 | =head2 Pragmata |
572 | |
09bef843 |
573 | C<use attrs> is now obsolescent, and is only provided for |
574 | backward-compatibility. It's been replaced by the C<sub : attributes> |
575 | syntax. See L<perlsub/"Subroutine Attributes"> and L<attributes>. |
576 | |
14218588 |
577 | C<use utf8> to enable UTF-8 and Unicode support. |
43165c05 |
578 | |
579 | C<use caller 'encoding'> allows modules to inherit pragmatic attributes |
580 | from the caller's context. C<encoding> is currently the only supported |
581 | attribute. |
9d73390d |
582 | |
4438c4b7 |
583 | Lexical warnings pragma, C<use warnings;>, to control optional warnings. |
6c67e1bb |
584 | |
14218588 |
585 | C<use filetest> to control the behaviour of filetests (C<-r> C<-w> ...). |
6c67e1bb |
586 | Currently only one subpragma implemented, "use filetest 'access';", |
14218588 |
587 | that enables the use of access(2) or equivalent to check |
6c67e1bb |
588 | permissions instead of using stat(2) as usual. This matters |
14218588 |
589 | in filesystems where there are ACLs (access control lists): the |
590 | stat(2) might lie, but access(2) knows better. |
6c67e1bb |
591 | |
ba8251e8 |
592 | =head1 Utility Changes |
593 | |
e02fdbd2 |
594 | Todo. |
595 | |
ba8251e8 |
596 | =head1 Documentation Changes |
597 | |
5fdc711f |
598 | =over 4 |
599 | |
600 | =item perlopentut.pod |
f8284313 |
601 | |
5fdc711f |
602 | A tutorial on using open() effectively. |
603 | |
604 | =item perlreftut.pod |
605 | |
606 | A tutorial that introduces the essentials of references. |
607 | |
14218588 |
608 | =item perltootc.pod |
609 | |
610 | A tutorial on managing class data for object modules. |
611 | |
5fdc711f |
612 | =back |
e02fdbd2 |
613 | |
ba8251e8 |
614 | =head1 New Diagnostics |
615 | |
09bef843 |
616 | =item "my sub" not yet implemented |
617 | |
618 | (F) Lexically scoped subroutines are not yet implemented. Don't try that |
619 | yet. |
620 | |
621 | =item %s package attribute may clash with future reserved word: %s |
622 | |
623 | (W) A lowercase attribute name was used that had a package-specific handler. |
624 | That name might have a meaning to Perl itself some day, even though it |
625 | doesn't yet. Perhaps you should use a mixed-case attribute name, instead. |
626 | See L<attributes>. |
627 | |
6b121555 |
628 | =item /%s/: Unrecognized escape \\%c passed through |
629 | |
630 | (W) You used a backslash-character combination which is not recognized |
7711098a |
631 | by Perl. This combination appears in an interpolated variable or a |
6b121555 |
632 | C<'>-delimited regular expression. |
633 | |
af8c498a |
634 | =item Filehandle %s opened only for output |
6b121555 |
635 | |
af8c498a |
636 | (W) You tried to read from a filehandle opened only for writing. If you |
637 | intended it to be a read-write filehandle, you needed to open it with |
638 | "+E<lt>" or "+E<gt>" or "+E<gt>E<gt>" instead of with "E<lt>" or nothing. If |
639 | you intended only to read from the file, use "E<lt>". See |
640 | L<perlfunc/open>. |
e02fdbd2 |
641 | |
09bef843 |
642 | =item Invalid %s attribute: %s |
643 | |
644 | The indicated attribute for a subroutine or variable was not recognized |
645 | by Perl or by a user-supplied handler. See L<attributes>. |
646 | |
647 | =item Invalid %s attributes: %s |
648 | |
649 | The indicated attributes for a subroutine or variable were not recognized |
650 | by Perl or by a user-supplied handler. See L<attributes>. |
651 | |
652 | =item Invalid separator character %s in attribute list |
653 | |
654 | (F) Something other than a comma or whitespace was seen between the |
655 | elements of an attribute list. If the previous attribute |
656 | had a parenthesised parameter list, perhaps that list was terminated |
657 | too soon. See L<attributes>. |
658 | |
06eaf0bc |
659 | =item Missing command in piped open |
660 | |
661 | (W) You used the C<open(FH, "| command")> or C<open(FH, "command |")> |
662 | construction, but the command was missing or blank. |
663 | |
09bef843 |
664 | =item Missing name in "my sub" |
665 | |
666 | (F) The reserved syntax for lexically scoped subroutines requires that they |
667 | have a name with which they can be found. |
668 | |
af8c498a |
669 | =item Unrecognized escape \\%c passed through |
670 | |
671 | (W) You used a backslash-character combination which is not recognized |
672 | by Perl. |
673 | |
09bef843 |
674 | =item Unterminated attribute parameter in attribute list |
675 | |
676 | (F) The lexer saw an opening (left) parenthesis character while parsing an |
677 | attribute list, but the matching closing (right) parenthesis |
678 | character was not found. You may need to add (or remove) a backslash |
679 | character to get your parentheses to balance. See L<attributes>. |
680 | |
681 | =item Unterminated attribute list |
682 | |
683 | (F) The lexer found something other than a simple identifier at the start |
684 | of an attribute, and it wasn't a semicolon or the start of a |
685 | block. Perhaps you terminated the parameter list of the previous attribute |
686 | too soon. See L<attributes>. |
687 | |
f10b0346 |
688 | =item defined(@array) is deprecated |
69794302 |
689 | |
690 | (D) defined() is not usually useful on arrays because it checks for an |
691 | undefined I<scalar> value. If you want to see if the array is empty, |
692 | just use C<if (@array) { # not empty }> for example. |
693 | |
f10b0346 |
694 | =item defined(%hash) is deprecated |
69794302 |
695 | |
696 | (D) defined() is not usually useful on hashes because it checks for an |
697 | undefined I<scalar> value. If you want to see if the hash is empty, |
698 | just use C<if (%hash) { # not empty }> for example. |
699 | |
09bef843 |
700 | =item Invalid separator character %s in subroutine attribute list |
701 | |
702 | (F) Something other than a comma or whitespace was seen between the |
703 | elements of a subroutine attribute list. If the previous attribute |
704 | had a parenthesised parameter list, perhaps that list was terminated |
705 | too soon. |
706 | |
707 | =item Unterminated attribute parameter in subroutine attribute list |
708 | |
709 | (F) The lexer saw an opening (left) parenthesis character while parsing a |
710 | subroutine attribute list, but the matching closing (right) parenthesis |
711 | character was not found. You may need to add (or remove) a backslash |
712 | character to get your parentheses to balance. |
713 | |
714 | =item Unterminated subroutine attribute list |
715 | |
716 | (F) The lexer found something other than a simple identifier at the start |
717 | of a subroutine attribute, and it wasn't a semicolon or the start of a |
718 | block. Perhaps you terminated the parameter list of the previous attribute |
719 | too soon. |
720 | |
ba8251e8 |
721 | =head1 Obsolete Diagnostics |
722 | |
e02fdbd2 |
723 | Todo. |
724 | |
04d420f9 |
725 | =head1 Configuration Changes |
726 | |
27806c82 |
727 | =head2 installusrbinperl |
728 | |
04d420f9 |
729 | You can use "Configure -Uinstallusrbinperl" which causes installperl |
730 | to skip installing perl also as /usr/bin/perl. This is useful if you |
731 | prefer not to modify /usr/bin for some reason or another but harmful |
732 | because many scripts assume to find Perl in /usr/bin/perl. |
733 | |
27806c82 |
734 | =head2 SOCKS support |
555834d1 |
735 | |
27806c82 |
736 | You can use "Configure -Dusesocks" which causes Perl to probe |
737 | for the SOCKS proxy protocol library, http://www.socks.nec.com/ |
04d420f9 |
738 | |
ba8251e8 |
739 | =head1 BUGS |
740 | |
741 | If you find what you think is a bug, you might check the headers of |
14218588 |
742 | articles recently posted to the comp.lang.perl.misc newsgroup. |
ba8251e8 |
743 | There may also be information at http://www.perl.com/perl/, the Perl |
744 | Home Page. |
745 | |
746 | If you believe you have an unreported bug, please run the B<perlbug> |
14218588 |
747 | program included with your release. Make sure to trim your bug down |
ba8251e8 |
748 | to a tiny but sufficient test case. Your bug report, along with the |
14218588 |
749 | output of C<perl -V>, will be sent off to perlbug@perl.com to be |
ba8251e8 |
750 | analysed by the Perl porting team. |
751 | |
752 | =head1 SEE ALSO |
753 | |
754 | The F<Changes> file for exhaustive details on what changed. |
755 | |
756 | The F<INSTALL> file for how to build Perl. |
757 | |
758 | The F<README> file for general stuff. |
759 | |
760 | The F<Artistic> and F<Copying> files for copyright information. |
761 | |
762 | =head1 HISTORY |
763 | |
764 | Written by Gurusamy Sarathy <F<gsar@umich.edu>>, with many contributions |
765 | from The Perl Porters. |
766 | |
767 | Send omissions or corrections to <F<perlbug@perl.com>>. |
768 | |
769 | =cut |