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1 | =head1 NAME |
2 | |
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3 | perldelta - what's new for perl5.006 (as of 5.005_54) |
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4 | |
5 | =head1 DESCRIPTION |
6 | |
7 | This document describes differences between the 5.005 release and this one. |
8 | |
9 | =head1 Incompatible Changes |
10 | |
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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 | |
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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 | |
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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 | |
58 | =head2 Binary Incompatibilities |
59 | |
60 | This release is not binary compatible with the 5.005 release and its |
61 | maintenance versions. |
62 | |
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63 | =head1 Core Changes |
64 | |
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65 | =head2 Binary numbers supported |
66 | |
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67 | Binary numbers are now supported as literals, in s?printf formats, and |
68 | C<oct()>: |
69 | |
70 | $answer = 0b101010; |
71 | printf "The answer is: %b\n", oct("0b101010"); |
72 | |
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73 | =head2 syswrite() ease-of-use |
74 | |
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75 | The length argument of C<syswrite()> is now optional. |
76 | |
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77 | =head2 64-bit support |
78 | |
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79 | Better 64-bit support -- but full support still a distant goal. One |
80 | must Configure with -Duse64bits to get Configure to probe for the |
81 | extent of 64-bit support. Depending on the platform (hints file) more |
82 | or less 64-awareness becomes available. As of 5.005_54 at least |
83 | somewhat 64-bit aware platforms are HP-UX 11 or better, Solaris 2.6 or |
84 | better, IRIX 6.2 or better. Naturally 64-bit platforms like Digital |
85 | UNIX and UNICOS also have 64-bit support. |
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86 | |
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87 | =head2 Better syntax checks on parenthesized unary operators |
88 | |
89 | Expressions such as: |
90 | |
91 | print defined(&foo,&bar,&baz); |
92 | print uc("foo","bar","baz"); |
93 | undef($foo,&bar); |
94 | |
95 | used to be accidentally allowed in earlier versions, and produced |
96 | unpredictable behavior. Some of them produced ancillary warnings |
97 | when used in this way, while others silently did the wrong thing. |
98 | |
99 | The parenthesized forms of most unary operators that expect a single |
100 | argument will now ensure that they are not called with more than one |
101 | argument, making the above cases syntax errors. Note that the usual |
102 | behavior of: |
103 | |
104 | print defined &foo, &bar, &baz; |
105 | print uc "foo", "bar", "baz"; |
106 | undef $foo, &bar; |
107 | |
108 | remains unchanged. See L<perlop>. |
109 | |
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110 | =head2 Improved C<qw//> operator |
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111 | |
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112 | The C<qw//> operator is now evaluated at compile time into a true list |
113 | instead of being replaced with a run time call to C<split()>. This |
114 | removes the confusing behavior of C<qw//> in scalar context stemming from |
115 | the older implementation, which inherited the behavior from split(). |
116 | |
117 | Thus: |
118 | |
119 | $foo = ($bar) = qw(a b c); print "$foo|$bar\n"; |
120 | |
121 | now correctly prints "3|a", instead of "2|a". |
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122 | |
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123 | =head2 pack() format 'Z' supported |
124 | |
125 | The new format type 'Z' is useful for packing and unpacking null-terminated |
126 | strings. See L<perlfunc/"pack">. |
127 | |
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128 | =head1 Significant bug fixes |
129 | |
130 | =head2 E<lt>HANDLEE<gt> on empty files |
131 | |
132 | With C<$/> set to C<undef>, slurping an empty file returns a string of |
133 | zero length (instead of C<undef>, as it used to) for the first time the |
134 | HANDLE is read. Subsequent reads yield C<undef>. |
135 | |
136 | This means that the following will append "foo" to an empty file (it used |
137 | to not do anything before): |
138 | |
139 | perl -0777 -pi -e 's/^/foo/' empty_file |
140 | |
141 | Note that the behavior of: |
142 | |
143 | perl -pi -e 's/^/foo/' empty_file |
144 | |
145 | is unchanged (it continues to leave the file empty). |
146 | |
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147 | =head1 Supported Platforms |
148 | |
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149 | =over 4 |
150 | |
151 | =item * |
152 | |
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153 | VM/ESA is now supported. |
154 | |
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155 | =item * |
156 | |
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157 | Siemens BS200 is now supported. |
158 | |
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159 | =item * |
160 | |
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161 | The Mach CThreads (NeXTstep) are now supported by the Thread extension. |
162 | |
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163 | =back |
164 | |
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165 | =head1 New tests |
166 | |
167 | =over 4 |
168 | |
169 | =item op/io_const |
170 | |
171 | IO constants (SEEK_*, _IO*). |
172 | |
173 | =item op/io_dir |
174 | |
175 | Directory-related IO methods (new, read, close, rewind, tied delete). |
176 | |
177 | =item op/io_multihomed |
178 | |
179 | INET sockets with multi-homed hosts. |
180 | |
181 | =item op/io_poll |
182 | |
183 | IO poll(). |
184 | |
185 | =item op/io_unix |
186 | |
187 | UNIX sockets. |
188 | |
189 | =item op/filetest |
190 | |
191 | File test operators. |
192 | |
193 | =item op/lex_assign |
194 | |
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195 | Verify operations that access pad objects (lexicals and temporaries). |
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196 | |
197 | =back |
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198 | |
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199 | =head1 Modules and Pragmata |
200 | |
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201 | =head2 Modules |
202 | |
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203 | =over 4 |
204 | |
205 | =item Dumpvalue |
206 | |
207 | Added Dumpvalue module provides screen dumps of Perl data. |
208 | |
209 | =item Benchmark |
210 | |
211 | You can now run tests for I<x> seconds instead of guessing the right |
212 | number of tests to run. |
213 | |
214 | =item Fcntl |
215 | |
216 | More Fcntl constants added: F_SETLK64, F_SETLKW64, O_LARGEFILE for |
217 | large (more than 4G) file access (the 64-bit support is not yet |
218 | working, though, so no need to get overly excited), Free/Net/OpenBSD |
219 | locking behaviour flags F_FLOCK, F_POSIX, Linux F_SHLCK, and |
220 | O_ACCMODE: the mask of O_RDONLY, O_WRONLY, and O_RDWR. |
221 | |
222 | =item Math::Complex |
223 | |
224 | The accessors methods Re, Im, arg, abs, rho, theta, methods can |
225 | ($z->Re()) now also act as mutators ($z->Re(3)). |
226 | |
227 | =item Math::Trig |
228 | |
229 | A little bit of radial trigonometry (cylindrical and spherical) added, |
230 | for example the great circle distance. |
231 | |
232 | =back |
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233 | |
234 | =head2 Pragmata |
235 | |
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236 | Lexical warnings pragma, "use warning;", to control optional warnings. |
237 | |
238 | Filetest pragma, to control the behaviour of filetests (C<-r> C<-w> ...). |
239 | Currently only one subpragma implemented, "use filetest 'access';", |
240 | that enables the use of access(2) or equivalent to check the |
241 | permissions instead of using stat(2) as usual. This matters |
242 | in filesystems where there are ACLs (access control lists), the |
243 | stat(2) might lie, while access(2) knows better. |
244 | |
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245 | =head1 Utility Changes |
246 | |
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247 | =head2 New Modules |
248 | |
249 | =over |
250 | |
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251 | Todo. |
252 | |
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253 | =back |
254 | |
255 | =head2 Changes in existing modules |
256 | |
257 | =over |
258 | |
259 | =item Exporter |
260 | |
261 | Exporter::expand() takes an import list and returns the expanded |
262 | list of names. |
263 | |
264 | =back |
265 | |
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266 | =head1 Documentation Changes |
267 | |
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268 | =over 4 |
269 | |
270 | =item perlopentut.pod |
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271 | |
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272 | A tutorial on using open() effectively. |
273 | |
274 | =item perlreftut.pod |
275 | |
276 | A tutorial that introduces the essentials of references. |
277 | |
278 | =back |
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279 | |
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280 | =head1 New Diagnostics |
281 | |
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282 | =item /%s/: Unrecognized escape \\%c passed through |
283 | |
284 | (W) You used a backslash-character combination which is not recognized |
285 | by Perl. This combination appears in an interpolated variable or a |
286 | C<'>-delimited regular expression. |
287 | |
288 | =item Unrecognized escape \\%c passed through |
289 | |
290 | (W) You used a backslash-character combination which is not recognized |
291 | by Perl. |
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292 | |
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293 | =item Missing command in piped open |
294 | |
295 | (W) You used the C<open(FH, "| command")> or C<open(FH, "command |")> |
296 | construction, but the command was missing or blank. |
297 | |
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298 | =head1 Obsolete Diagnostics |
299 | |
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300 | Todo. |
301 | |
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302 | =head1 Configuration Changes |
303 | |
304 | You can use "Configure -Uinstallusrbinperl" which causes installperl |
305 | to skip installing perl also as /usr/bin/perl. This is useful if you |
306 | prefer not to modify /usr/bin for some reason or another but harmful |
307 | because many scripts assume to find Perl in /usr/bin/perl. |
308 | |
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309 | =head1 BUGS |
310 | |
311 | If you find what you think is a bug, you might check the headers of |
312 | recently posted articles in the comp.lang.perl.misc newsgroup. |
313 | There may also be information at http://www.perl.com/perl/, the Perl |
314 | Home Page. |
315 | |
316 | If you believe you have an unreported bug, please run the B<perlbug> |
317 | program included with your release. Make sure you trim your bug down |
318 | to a tiny but sufficient test case. Your bug report, along with the |
319 | output of C<perl -V>, will be sent off to <F<perlbug@perl.com>> to be |
320 | analysed by the Perl porting team. |
321 | |
322 | =head1 SEE ALSO |
323 | |
324 | The F<Changes> file for exhaustive details on what changed. |
325 | |
326 | The F<INSTALL> file for how to build Perl. |
327 | |
328 | The F<README> file for general stuff. |
329 | |
330 | The F<Artistic> and F<Copying> files for copyright information. |
331 | |
332 | =head1 HISTORY |
333 | |
334 | Written by Gurusamy Sarathy <F<gsar@umich.edu>>, with many contributions |
335 | from The Perl Porters. |
336 | |
337 | Send omissions or corrections to <F<perlbug@perl.com>>. |
338 | |
339 | =cut |