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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_62) |
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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 | |
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12 | This document describes differences between the 5.005 release and this one. |
13 | |
14 | =head1 Incompatible Changes |
15 | |
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16 | =head2 Perl Source Incompatibilities |
17 | |
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18 | Beware that any new warnings that have been added or enhanced old |
19 | warnings are B<not> considered incompatible changes. |
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20 | |
21 | Since all new warnings must be explicitly requested via the C<-w> |
22 | switch or the C<warnings> pragma, it is ultimately the programmer's |
23 | responsibility to ensure that warnings are enabled judiciously. |
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24 | |
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25 | =over 4 |
26 | |
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27 | =item STOP is a new keyword |
28 | |
29 | In addition to C<BEGIN>, C<INIT> and C<END>, subroutines named |
30 | C<STOP> are now special. They are queued up for execution at the |
31 | end of compilation, and cannot be called directly. |
32 | |
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33 | =item Treatment of list slices of undef has changed |
34 | |
35 | When taking a slice of a literal list (as opposed to a slice of |
36 | an array or hash), Perl used to return an empty list if the |
37 | result happened to be composed of all undef values. |
38 | |
39 | The new behavior is to produce an empty list if (and only if) |
40 | the original list was empty. Consider the following example: |
41 | |
42 | @a = (1,undef,undef,2)[2,1,2]; |
43 | |
44 | The old behavior would have resulted in @a having no elements. |
45 | The new behavior ensures it has three undefined elements. |
46 | |
47 | Note in particular that the behavior of slices of the following |
48 | cases remains unchanged: |
49 | |
50 | @a = ()[1,2]; |
51 | @a = (getpwent)[7,0]; |
52 | @a = (anything_returning_empty_list())[2,1,2]; |
53 | @a = @b[2,1,2]; |
54 | @a = @c{'a','b','c'}; |
55 | |
56 | See L<perldata>. |
57 | |
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58 | =item Possibly changed pseudo-random number generator |
59 | |
60 | In 5.005_0x and earlier, perl's rand() function used the C library |
61 | rand(3) function. As of 5.005_52, Configure tests for drand48(), |
62 | random(), and rand() (in that order) and picks the first one it finds. |
63 | Perl programs that depend on reproducing a specific set of pseudo-random |
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64 | numbers will now likely produce different output. You can use |
65 | C<sh Configure -Drandfunc=rand> to obtain the old behavior. |
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66 | |
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67 | =item Hashing function for hash keys has changed |
68 | |
69 | Perl hashes are not order preserving. The apparently random order |
70 | encountered when iterating on the contents of a hash is determined |
71 | by the hashing algorithm used. To improve the distribution of lower |
72 | bits in the hashed value, the algorithm has changed slightly as of |
73 | 5.005_52. When iterating over hashes, this may yield a random order |
74 | that is B<different> from that of previous versions. |
75 | |
76 | =item C<undef> fails on read only values |
77 | |
78 | Using the C<undef> operator on a readonly value (such as $1) has |
79 | the same effect as assigning C<undef> to the readonly value--it |
80 | throws an exception. |
81 | |
82 | =item Close-on-exec bit may be set on pipe() handles |
83 | |
84 | On systems that support a close-on-exec flag on filehandles, the |
85 | flag will be set for any handles created by pipe(), if that is |
86 | warranted by the value of $^F that may be in effect. Earlier |
87 | versions neglected to set the flag for handles created with |
88 | pipe(). See L<perlfunc/pipe> and L<perlvar/$^F>. |
89 | |
90 | =item Writing C<"$$1"> to mean C<"${$}1"> is unsupported |
91 | |
92 | Perl 5.004 deprecated the interpretation of C<$$1> and |
93 | similar within interpolated strings to mean C<$$ . "1">, |
94 | but still allowed it. |
95 | |
96 | In Perl 5.6 and later, C<"$$1"> always means C<"${$1}">. |
97 | |
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98 | =item delete(), values() and C<\(%h)> operate on aliases to values, not copies |
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99 | |
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100 | delete(), each(), values() and hashes in a list context return the actual |
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101 | values in the hash, instead of copies (as they used to in earlier |
102 | versions). Typical idioms for using these constructs copy the |
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103 | returned values, but this can make a significant difference when |
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104 | creating references to the returned values. |
105 | |
106 | Keys in the hash are still returned as copies when iterating on |
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107 | a hash. |
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108 | |
109 | =item vec(EXPR,OFFSET,BITS) enforces powers-of-two BITS |
110 | |
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111 | vec() generates a run-time error if the BITS argument is not |
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112 | a valid power-of-two integer. |
113 | |
114 | =item Text of some diagnostic output has changed |
115 | |
116 | Most references to internal Perl operations in diagnostics |
117 | have been changed to be more descriptive. This may be an |
118 | issue for programs that may incorrectly rely on the exact |
119 | text of diagnostics for proper functioning. |
120 | |
121 | =item C<%@> has been removed |
122 | |
123 | The undocumented special variable C<%@> that used to accumulate |
124 | "background" errors (such as those that happen in DESTROY()) |
125 | has been removed, because it could potentially result in memory |
126 | leaks. |
127 | |
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128 | =item Parenthesized not() behaves like a list operator |
129 | |
130 | The C<not> operator now falls under the "if it looks like a function, |
131 | it behaves like a function" rule. |
132 | |
133 | As a result, the parenthesized form can be used with C<grep> and C<map>. |
134 | The following construct used to be a syntax error before, but it works |
135 | as expected now: |
136 | |
137 | grep not($_), @things; |
138 | |
139 | On the other hand, using C<not> with a literal list slice may not |
140 | work. The following previously allowed construct: |
141 | |
142 | print not (1,2,3)[0]; |
143 | |
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144 | needs to be written with additional parentheses now: |
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145 | |
146 | print not((1,2,3)[0]); |
147 | |
148 | The behavior remains unaffected when C<not> is not followed by parentheses. |
149 | |
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150 | =back |
151 | |
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152 | =head2 C Source Incompatibilities |
153 | |
154 | =over 4 |
155 | |
156 | =item C<PERL_POLLUTE> |
157 | |
158 | Release 5.005 grandfathered old global symbol names by providing preprocessor |
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159 | macros for extension source compatibility. As of release 5.6, these |
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160 | preprocessor definitions are not available by default. You need to explicitly |
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161 | compile perl with C<-DPERL_POLLUTE> to get these definitions. For |
162 | extensions still using the old symbols, this option can be |
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163 | specified via MakeMaker: |
164 | |
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165 | perl Makefile.PL POLLUTE=1 |
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166 | |
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167 | =item C<PERL_IMPLICIT_CONTEXT> |
168 | |
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169 | PERL_IMPLICIT_CONTEXT is automatically enabled whenever Perl is built |
170 | with one of -Dusethreads, -Dusemultiplicity, or both. It is not |
171 | intended to be enabled by users at this time. |
172 | |
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173 | This new build option provides a set of macros for all API functions |
174 | such that an implicit interpreter/thread context argument is passed to |
175 | every API function. As a result of this, something like C<sv_setsv(foo,bar)> |
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176 | amounts to a macro invocation that actually translates to something like |
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177 | C<Perl_sv_setsv(my_perl,foo,bar)>. While this is generally expected |
178 | to not have any significant source compatibility issues, the difference |
179 | between a macro and a real function call will need to be considered. |
180 | |
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181 | This means that there B<is> a source compatibility issue as a result of |
182 | this if your extensions attempt to use pointers to any of the Perl API |
183 | functions. |
184 | |
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185 | Note that the above issue is not relevant to the default build of |
186 | Perl, whose interfaces continue to match those of prior versions |
187 | (but subject to the other options described here). |
188 | |
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189 | See L<perlguts/"The Perl API"> for detailed information on the |
190 | ramifications of building Perl using this option. |
191 | |
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192 | =item C<PERL_POLLUTE_MALLOC> |
193 | |
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194 | Enabling Perl's malloc in release 5.005 and earlier caused |
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195 | the namespace of system versions of the malloc family of functions to |
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196 | be usurped by the Perl versions, since by default they used the |
197 | same names. |
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198 | |
199 | Besides causing problems on platforms that do not allow these functions to |
200 | be cleanly replaced, this also meant that the system versions could not |
201 | be called in programs that used Perl's malloc. Previous versions of Perl |
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202 | have allowed this behaviour to be suppressed with the HIDEMYMALLOC and |
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203 | EMBEDMYMALLOC preprocessor definitions. |
204 | |
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205 | As of release 5.6, Perl's malloc family of functions have default names |
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206 | distinct from the system versions. You need to explicitly compile perl with |
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207 | C<-DPERL_POLLUTE_MALLOC> to get the older behaviour. HIDEMYMALLOC |
208 | and EMBEDMYMALLOC have no effect, since the behaviour they enabled is now |
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209 | the default. |
210 | |
211 | Note that these functions do B<not> constitute Perl's memory allocation API. |
212 | See L<perlguts/"Memory Allocation"> for further information about that. |
213 | |
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214 | =back |
215 | |
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216 | =head2 Compatible C Source API Changes |
217 | |
218 | =over |
219 | |
220 | =item C<PATCHLEVEL> is now C<PERL_VERSION> |
221 | |
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222 | The cpp macros C<PERL_REVISION>, C<PERL_VERSION>, and C<PERL_SUBVERSION> |
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223 | are now available by default from perl.h, and reflect the base revision, |
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224 | patchlevel, and subversion respectively. C<PERL_REVISION> had no |
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225 | prior equivalent, while C<PERL_VERSION> and C<PERL_SUBVERSION> were |
226 | previously available as C<PATCHLEVEL> and C<SUBVERSION>. |
227 | |
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228 | The new names cause less pollution of the B<cpp> namespace and reflect what |
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229 | the numbers have come to stand for in common practice. For compatibility, |
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230 | the old names are still supported when F<patchlevel.h> is explicitly |
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231 | included (as required before), so there is no source incompatibility |
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232 | from the change. |
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233 | |
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234 | =item Support for C++ exceptions |
235 | |
236 | change#3386, also needs perlguts documentation |
237 | [TODO - Chip Salzenberg <chip@perlsupport.com>] |
238 | |
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239 | =back |
240 | |
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241 | =head2 Binary Incompatibilities |
242 | |
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243 | The default build of this release is binary compatible with the 5.005 |
244 | release or its maintenance versions. |
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245 | |
246 | The usethreads or usemultiplicity builds are B<not> binary compatible |
247 | with the corresponding builds in 5.005. |
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248 | |
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249 | =head1 Installation and Configuration Improvements |
250 | |
251 | =head2 New Configure flags |
252 | |
253 | The following new flags may be enabled on the Configure command line |
254 | by running Configure with C<-Dflag>. |
255 | |
256 | usemultiplicity |
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257 | |
258 | uselongdouble |
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259 | usemorebits |
260 | uselargefiles |
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261 | |
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262 | =head2 -Dusethreads and -Duse64bits now more daring |
263 | |
264 | The Configure options enabling the use of threads and the use of |
265 | 64-bitness are now more daring in the sense that they no more have |
266 | an explicit list of operating systems of known threads/64-bit |
267 | capabilities. In other words: if your operating system has the |
268 | necessary APIs, you should be able just to go ahead and use them. |
269 | See also L<"64-bit support">. |
270 | |
271 | =head2 Long Doubles |
272 | |
273 | Some platforms have "long doubles", floating point numbers of even |
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274 | larger range than ordinary "doubles". To enable using long doubles for |
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275 | Perl's scalars, use -Duselongdouble. |
276 | |
277 | =head2 -Dusemorebits |
278 | |
279 | You can enable both -Duse64bits and -Dlongdouble by -Dusemorebits. |
280 | See also L<"64-bit support">. |
281 | |
282 | =head2 -Duselargefiles |
283 | |
284 | Some platforms support large files, files larger than two gigabytes. |
285 | See L<"Large file support"> for more information. |
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286 | |
287 | =head2 installusrbinperl |
288 | |
289 | You can use "Configure -Uinstallusrbinperl" which causes installperl |
290 | to skip installing perl also as /usr/bin/perl. This is useful if you |
291 | prefer not to modify /usr/bin for some reason or another but harmful |
292 | because many scripts assume to find Perl in /usr/bin/perl. |
293 | |
294 | =head2 SOCKS support |
295 | |
296 | You can use "Configure -Dusesocks" which causes Perl to probe |
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297 | for the SOCKS (v5, not v4) proxy protocol library, |
298 | http://www.socks.nec.com/ |
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299 | |
300 | =head2 C<-A> flag |
301 | |
302 | You can "post-edit" the Configure variables using the Configure C<-A> |
303 | flag. The editing happens immediately after the platform specific |
304 | hints files have been processed but before the actual configuration |
305 | process starts. Run C<Configure -h> to find out the full C<-A> syntax. |
306 | |
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307 | =head2 Enhanced Installation Directories |
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308 | |
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309 | The installation structure has been enriched to improve the support for |
310 | maintaining multiple versions of perl, to provide locations for |
311 | vendor-supplied modules and scripts, and to ease maintenance of |
312 | locally-added modules and scripts. See the section on Installation |
313 | Directories in the INSTALL file for complete details. For most users |
314 | building and installing from source, the defaults should be fine. |
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315 | |
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316 | =head1 Core Changes |
317 | |
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318 | =head2 Unicode and UTF-8 support |
319 | |
320 | Perl can optionally use UTF-8 as its internal representation for character |
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321 | strings. The C<utf8> pragma enables this support in the current lexical |
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322 | scope. See L<utf8> for more information. |
323 | |
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324 | =head2 Interpreter threads |
325 | |
326 | WARNING: This is an experimental feature in a pre-alpha state. Use |
327 | at your own risk. |
328 | |
329 | Perl 5.005_63 introduces the beginnings of support for running multiple |
330 | interpreters concurrently in different threads. In conjunction with |
331 | the perl_clone() API call, which can be used to selectively duplicate |
332 | the state of any given interpreter, it is possible to compile a |
333 | piece of code once in an interpreter, clone that interpreter |
334 | one or more times, and run all the resulting interpreters in distinct |
335 | threads. |
336 | |
337 | On Windows, this feature is used to emulate fork() at the interpreter |
338 | level. See L<perlfork>. |
339 | |
340 | This feature is still in evolution. It is eventually meant to be used |
341 | to selectively clone a subroutine and data reachable from that |
342 | subroutine in a separate interpreter and run the cloned subroutine |
343 | in a separate thread. Since there is no shared data between the |
344 | interpreters, little or no locking will be needed (unless parts of |
345 | the symbol table are explicitly shared). This is obviously intended |
346 | to be an easy-to-use replacement for the existing threads support. |
347 | |
348 | Support for cloning interpreters must currently be manually enabled |
349 | by defining the cpp macro USE_ITHREADS on non-Windows platforms. |
350 | (See win32/Makefile for how to enable it on Windows.) The resulting |
351 | perl executable will be functionally identical to one that was built |
352 | without USE_ITHREADS, but the perl_clone() API call will only be |
353 | available in the former. |
354 | |
355 | USE_ITHREADS enables Perl source code changes that provide a clear |
356 | separation between the op tree and the data it operates with. The |
357 | former is considered immutable, and can therefore be shared between |
358 | an interpreter and all of its clones, while the latter is considered |
359 | local to each interpreter, and is therefore copied for each clone. |
360 | |
361 | Note that building Perl with the -Dusemultiplicity Configure option |
362 | is adequate if you wish to run multiple B<independent> interpreters |
363 | concurrently in different threads. USE_ITHREADS only needs to be |
364 | enabled if you wish to obtain access to perl_clone() and cloned |
365 | interpreters. |
366 | |
367 | [XXX TODO - the Compiler backends may be broken when USE_ITHREADS is |
368 | enabled.] |
369 | |
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370 | =head2 Lexically scoped warning categories |
371 | |
372 | You can now control the granularity of warnings emitted by perl at a finer |
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373 | level using the C<use warnings> pragma. See L<warnings> and L<perllexwarn> |
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374 | for details. |
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375 | |
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376 | =head2 Lvalue subroutines |
377 | |
378 | WARNING: This is an experimental feature. |
379 | |
380 | change#4081 |
381 | [TODO - Ilya Zakharevich <ilya@math.ohio-state.edu>, |
382 | Tuomas Lukka <lukka@fas.harvard.edu>)] |
383 | |
384 | =head2 "our" declarations |
385 | |
386 | An "our" declaration introduces a value that can be best understood |
387 | as a lexically scoped symbolic alias to a global variable in the |
388 | current package. This is mostly useful as an alternative to the |
389 | C<vars> pragma, but also provides the opportunity to introduce |
390 | typing and other attributes for such variables. See L<perlfunc/our>. |
391 | |
392 | =head2 Weak references |
393 | |
394 | WARNING: This is an experimental feature. |
395 | |
396 | change#3385, also need perlguts documentation |
397 | |
398 | [TODO - Tuomas Lukka <lukka@fas.harvard.edu>] |
399 | |
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400 | =head2 File globbing implemented internally |
401 | |
402 | WARNING: This is currently an experimental feature. Interfaces and |
403 | implementation are likely to change. |
404 | |
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405 | Perl now uses the File::Glob implementation of the glob() operator |
406 | automatically. This avoids using an external csh process and the |
407 | problems associated with it. |
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408 | |
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409 | =head2 Binary numbers supported |
410 | |
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411 | Binary numbers are now supported as literals, in s?printf formats, and |
412 | C<oct()>: |
413 | |
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414 | $answer = 0b101010; |
415 | printf "The answer is: %b\n", oct("0b101010"); |
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416 | |
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417 | =head2 Some arrows may be omitted in calls through references |
418 | |
419 | Perl now allows the arrow to be omitted in many constructs |
420 | involving subroutine calls through references. For example, |
421 | C<$foo[10]->('foo')> may now be written C<$foo[10]('foo')>. |
422 | This is rather similar to how the arrow may be omitted from |
423 | C<$foo[10]->{'foo'}>. Note however, that the arrow is still |
424 | required for C<foo(10)->('bar')>. |
425 | |
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426 | =head2 syswrite() ease-of-use |
427 | |
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428 | The length argument of C<syswrite()> has become optional. |
429 | |
430 | =head2 Filehandles can be autovivified |
431 | |
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432 | Similar to how constructs such as C<$x->[0]> autovivify a reference, |
433 | open() now autovivifies a filehandle if the first argument is an |
434 | uninitialized variable. This allows the constructs C<open(my $fh, ...)> and |
435 | C<open(local $fh,...)> to be used to create filehandles that will |
436 | conveniently be closed automatically when the scope ends, provided there |
437 | are no other references to them. This largely eliminates the need for |
438 | typeglobs when opening filehandles that must be passed around, as in the |
439 | following example: |
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440 | |
441 | sub myopen { |
442 | open my $fh, "@_" |
443 | or die "Can't open '@_': $!"; |
444 | return $fh; |
445 | } |
446 | |
447 | { |
448 | my $f = myopen("</etc/motd"); |
449 | print <$f>; |
450 | # $f implicitly closed here |
451 | } |
452 | |
453 | [TODO - this idiom needs more pod penetration] |
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454 | |
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455 | =head2 64-bit support |
456 | |
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457 | All platforms that have 64-bit integers either (a) natively as longs |
458 | or ints (b) via special compiler flags (c) using long long are able to |
459 | use "quads" (64-integers) as follows: |
460 | |
461 | =over 4 |
462 | |
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463 | =item * |
464 | |
465 | constants (decimal, hexadecimal, octal, binary) in the code |
466 | |
467 | =item * |
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468 | |
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469 | arguments to oct() and hex() |
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470 | |
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471 | =item * |
472 | |
473 | arguments to print(), printf() and sprintf() (flag prefixes ll, L, q) |
474 | |
475 | =item * |
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476 | |
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477 | printed as such |
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478 | |
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479 | =item * |
480 | |
481 | pack() and unpack() "q" and "Q" formats |
482 | |
483 | =item * |
484 | |
485 | in basic arithmetics: + - * / % |
486 | |
487 | =item * |
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488 | |
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489 | vec() (but see the below note about bit arithmetics) |
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490 | |
491 | =back |
492 | |
493 | Note that unless you have the case (a) you will have to configure |
494 | and compile Perl using the -Duse64bits Configure flag. |
495 | |
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496 | Unfortunately bit arithmetics (&, |, ^, ~, <<, >>) for numbers are not |
497 | 64-bit clean, they are explictly forced to be 32-bit. Bit arithmetics |
498 | for bit vectors (created by vec()) are not limited in their width. |
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499 | |
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500 | Last but not least: note that due to Perl's habit of always using |
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501 | floating point numbers the quads are still not true integers. |
502 | When quads overflow their limits (0...18_446_744_073_709_551_615 unsigned, |
503 | -9_223_372_036_854_775_808...9_223_372_036_854_775_807 signed), they |
504 | are silently promoted to floating point numbers, after which they will |
505 | start losing precision (their lower digits). |
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506 | |
507 | =head2 Large file support |
508 | |
509 | If you have filesystems that support "large files" (files larger than |
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510 | 2 gigabytes), you may now also be able to create and access them from |
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511 | Perl. You have to use Configure -Duselargefiles. Turning on the |
512 | large file support turns on also the 64-bit support, for obvious reasons. |
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513 | |
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514 | Note that in addition to requiring a proper file system to do large |
515 | files you may also need to adjust your per-process (or your |
516 | per-system, or per-process-group, or per-user-group) maximum filesize |
517 | limits before running Perl scripts that try to handle large files, |
518 | especially if you intend to write such files. |
519 | |
520 | Finally, in addition to your process/process group maximum filesize |
521 | limits, you may have quota limits on your filesystems that stop you |
522 | (your user id or your user group id) from using large files. |
523 | |
524 | Adjusting your process/user/group/file system/operating system limits |
525 | is outside the scope of Perl core language. For process limits, you |
526 | may try increasing the limits using your shell's limits/limit/ulimit |
527 | command before running Perl. The BSD::Resource extension (not |
528 | included with the standard Perl distribution) may also be of use, it |
529 | offers the getrlimit/setrlimit interface that can be used to adjust |
530 | process resource usage limits, including the maximum filesize limit. |
475d79b5 |
531 | |
aa855319 |
532 | =head2 Long doubles |
533 | |
534 | In some systems you may be able to use long doubles to enhance the |
535 | range of precision of your double precision floating point numbers |
536 | (that is, Perl's numbers). Use Configure -Duselongdouble to enable |
537 | this support (if it is available). |
538 | |
539 | =head2 "more bits" |
540 | |
541 | You can Configure -Dusemorebits to turn on both the 64-bit support |
542 | and the long double support. |
09bef843 |
543 | |
43481408 |
544 | =head2 Enhanced support for sort() subroutines |
545 | |
546 | Perl subroutines with a prototype of C<($$)> and XSUBs in general can |
547 | now be used as sort subroutines. In either case, the two elements to |
af365420 |
548 | be compared are passed as normal parameters in @_. See L<perlfunc/sort>. |
43481408 |
549 | |
550 | For unprototyped sort subroutines, the historical behavior of passing |
551 | the elements to be compared as the global variables $a and $b remains |
552 | unchanged. |
553 | |
62c18ce2 |
554 | =head2 Better syntax checks on parenthesized unary operators |
555 | |
556 | Expressions such as: |
557 | |
14218588 |
558 | print defined(&foo,&bar,&baz); |
559 | print uc("foo","bar","baz"); |
560 | undef($foo,&bar); |
62c18ce2 |
561 | |
7711098a |
562 | used to be accidentally allowed in earlier versions, and produced |
14218588 |
563 | unpredictable behaviour. Some produced ancillary warnings |
564 | when used in this way; others silently did the wrong thing. |
62c18ce2 |
565 | |
566 | The parenthesized forms of most unary operators that expect a single |
14218588 |
567 | argument now ensure that they are not called with more than one |
568 | argument, making the cases shown above syntax errors. The usual |
569 | behaviour of: |
62c18ce2 |
570 | |
14218588 |
571 | print defined &foo, &bar, &baz; |
572 | print uc "foo", "bar", "baz"; |
573 | undef $foo, &bar; |
62c18ce2 |
574 | |
575 | remains unchanged. See L<perlop>. |
576 | |
3e3318e7 |
577 | =head2 POSIX character class syntax [: :] supported |
578 | |
579 | For example to match alphabetic characters use /[[:alpha:]]/. |
580 | See L<perlre> for details. |
581 | |
5a929a98 |
582 | =head2 Improved C<qw//> operator |
8127e0e3 |
583 | |
26ef7447 |
584 | The C<qw//> operator is now evaluated at compile time into a true list |
585 | instead of being replaced with a run time call to C<split()>. This |
14218588 |
586 | removes the confusing misbehaviour of C<qw//> in scalar context, which |
587 | had inherited that behaviour from split(). |
26ef7447 |
588 | |
589 | Thus: |
590 | |
591 | $foo = ($bar) = qw(a b c); print "$foo|$bar\n"; |
592 | |
593 | now correctly prints "3|a", instead of "2|a". |
8127e0e3 |
594 | |
5a929a98 |
595 | =head2 pack() format 'Z' supported |
596 | |
597 | The new format type 'Z' is useful for packing and unpacking null-terminated |
598 | strings. See L<perlfunc/"pack">. |
599 | |
4d0c1c44 |
600 | =head2 pack() format modifier '!' supported |
ee3907e2 |
601 | |
14218588 |
602 | The new format type modifier '!' is useful for packing and unpacking |
ee3907e2 |
603 | native shorts, ints, and longs. See L<perlfunc/"pack">. |
604 | |
f29c64d6 |
605 | =head2 pack() and unpack() support counted strings |
606 | |
a5222a85 |
607 | The template character '/' can be used to specify a counted string |
f29c64d6 |
608 | type to be packed or unpacked. See L<perlfunc/"pack">. |
609 | |
a5222a85 |
610 | =head2 Comments in pack() templates |
611 | |
612 | The '#' character in a template introduces a comment up to |
613 | end of the line. This facilitates documentation of pack() |
614 | templates. |
615 | |
2b92dfce |
616 | =head2 $^X variables may now have names longer than one character |
617 | |
618 | Formerly, $^X was synonymous with ${"\cX"}, but $^XY was a syntax |
619 | error. Now variable names that begin with a control character may be |
620 | arbitrarily long. However, for compatibility reasons, these variables |
621 | I<must> be written with explicit braces, as C<${^XY}> for example. |
14218588 |
622 | C<${^XYZ}> is synonymous with ${"\cXYZ"}. Variable names with more |
2b92dfce |
623 | than one control character, such as C<${^XY^Z}>, are illegal. |
624 | |
14218588 |
625 | The old syntax has not changed. As before, `^X' may be either a |
626 | literal control-X character or the two-character sequence `caret' plus |
627 | `X'. When braces are omitted, the variable name stops after the |
2b92dfce |
628 | control character. Thus C<"$^XYZ"> continues to be synonymous with |
7711098a |
629 | C<$^X . "YZ"> as before. |
2b92dfce |
630 | |
631 | As before, lexical variables may not have names beginning with control |
632 | characters. As before, variables whose names begin with a control |
14218588 |
633 | character are always forced to be in package `main'. All such variables |
634 | are reserved for future extensions, except those that begin with |
09bef843 |
635 | C<^_>, which may be used by user programs and are guaranteed not to |
14218588 |
636 | acquire special meaning in any future version of Perl. |
2b92dfce |
637 | |
09bef843 |
638 | =head2 C<use attrs> implicit in subroutine attributes |
639 | |
640 | Formerly, if you wanted to mark a subroutine as being a method call or |
641 | as requiring an automatic lock() when it is entered, you had to declare |
642 | that with a C<use attrs> pragma in the body of the subroutine. |
643 | That can now be accomplished with a declaration syntax, like this: |
644 | |
645 | sub mymethod : locked, method ; |
646 | ... |
647 | sub mymethod : locked, method { |
648 | ... |
649 | } |
650 | |
651 | F<AutoSplit.pm> and F<SelfLoader.pm> have been updated to keep the attributes |
652 | with the stubs they provide. See L<attributes>. |
653 | |
a5222a85 |
654 | =head2 Regular expression improvements |
655 | |
656 | change#2827,2373,2372,2365,1813,1800,4112,4158,4215,4301 |
657 | [TODO - Ilya Zakharevich <ilya@math.ohio-state.edu>] |
658 | |
659 | =head2 Overloading improvements |
660 | |
661 | change#2150 |
662 | [TODO - Ilya Zakharevich <ilya@math.ohio-state.edu>] |
663 | |
664 | =head2 open() with more than two arguments |
665 | |
666 | [TODO - Ilya Zakharevich <ilya@math.ohio-state.edu>] |
667 | |
668 | =head2 Support for interpolating named characters |
669 | |
670 | change#4052 |
671 | [TODO - Ilya Zakharevich <ilya@math.ohio-state.edu>] |
672 | |
08cd8952 |
673 | =head2 Experimental support for user-hooks in @INC |
a5222a85 |
674 | |
675 | [TODO - Ken Fox <kfox@ford.com>] |
676 | |
677 | =head2 C<require> and C<do> may be overridden |
678 | |
679 | C<require> and C<do 'file'> operations may be overridden locally |
680 | by importing subroutines of the same name into the current package |
681 | (or globally by importing them into the CORE::GLOBAL:: namespace). |
682 | Overriding C<require> will also affect C<use>, provided the override |
683 | is visible at compile-time. |
684 | See L<perlsub/"Overriding Built-in Functions">. |
685 | |
686 | =head2 New variable $^C reflects C<-c> switch |
687 | |
08cd8952 |
688 | C<$^C> has a boolean value that reflects whether perl is being run |
a5222a85 |
689 | in compile-only mode (i.e. via the C<-c> switch). Since |
690 | BEGIN blocks are executed under such conditions, this variable |
691 | enables perl code to determine whether actions that make sense |
692 | only during normal running are warranted. See L<perlvar>. |
693 | |
4f25aa18 |
694 | =head2 STOP blocks |
695 | |
696 | Arbitrary code can be queued for execution when Perl has finished |
697 | parsing the program (i.e. when the compile phase ends) using STOP |
698 | blocks. These behave similar to END blocks, except for being |
699 | called at the end of compilation rather than at the end of execution. |
700 | |
a5222a85 |
701 | =head2 Optional Y2K warnings |
702 | |
703 | If Perl is built with the cpp macro C<PERL_Y2KWARN> defined, |
704 | it emits optional warnings when concatenating the number 19 |
705 | with another number. |
706 | |
707 | This behavior must be specifically enabled when running Configure. |
708 | See L<INSTALL> and L<README.Y2K>. |
709 | |
fbad3eb5 |
710 | =head1 Significant bug fixes |
711 | |
712 | =head2 E<lt>HANDLEE<gt> on empty files |
713 | |
714 | With C<$/> set to C<undef>, slurping an empty file returns a string of |
14218588 |
715 | zero length (instead of C<undef>, as it used to) the first time the |
716 | HANDLE is read. Further reads yield C<undef>. |
fbad3eb5 |
717 | |
718 | This means that the following will append "foo" to an empty file (it used |
14218588 |
719 | to do nothing): |
fbad3eb5 |
720 | |
721 | perl -0777 -pi -e 's/^/foo/' empty_file |
722 | |
14218588 |
723 | The behaviour of: |
fbad3eb5 |
724 | |
725 | perl -pi -e 's/^/foo/' empty_file |
726 | |
727 | is unchanged (it continues to leave the file empty). |
728 | |
0244c3a4 |
729 | =head2 C<eval '...'> improvements |
730 | |
731 | Line numbers (as reflected by caller() and most diagnostics) within |
732 | C<eval '...'> were often incorrect when here documents were involved. |
733 | This has been corrected. |
734 | |
735 | Lexical lookups for variables appearing in C<eval '...'> within |
736 | functions that were themselves called within an C<eval '...'> were |
14218588 |
737 | searching the wrong place for lexicals. The lexical search now |
738 | correctly ends at the subroutine's block boundary. |
0244c3a4 |
739 | |
740 | Parsing of here documents used to be flawed when they appeared as |
741 | the replacement expression in C<eval 's/.../.../e'>. This has |
742 | been fixed. |
743 | |
a5222a85 |
744 | =head2 All compilation errors are true errors |
745 | |
746 | Some "errors" encountered at compile time were by neccessity |
747 | generated as warnings followed by eventual termination of the |
748 | program. This enabled more such errors to be reported in a |
749 | single run, rather than causing a hard stop at the first error |
750 | that was encountered. |
751 | |
752 | The mechanism for reporting such errors has been reimplemented |
753 | to queue compile-time errors and report them at the end of the |
754 | compilation as true errors rather than as warnings. This fixes |
08cd8952 |
755 | cases where error messages leaked through in the form of warnings |
756 | when code was compiled at run time using C<eval STRING>, and |
757 | also allows such errors to be reliably trapped using __DIE__ hooks. |
a5222a85 |
758 | |
45bc9206 |
759 | =head2 Automatic flushing of output buffers |
760 | |
14218588 |
761 | fork(), exec(), system(), qx//, and pipe open()s now flush buffers |
762 | of all files opened for output when the operation |
763 | was attempted. This mostly eliminates confusing |
45bc9206 |
764 | buffering mishaps suffered by users unaware of how Perl internally |
14218588 |
765 | handles I/O. |
45bc9206 |
766 | |
af8c498a |
767 | =head2 Better diagnostics on meaningless filehandle operations |
768 | |
769 | Constructs such as C<open(E<lt>FHE<gt>)> and C<close(E<lt>FHE<gt>)> |
770 | are compile time errors. Attempting to read from filehandles that |
771 | were opened only for writing will now produce warnings (just as |
772 | writing to read-only filehandles does). |
773 | |
a5222a85 |
774 | =head2 Where possible, buffered data discarded from duped input filehandle |
775 | |
776 | C<open(NEW, "E<lt>&OLD")> now attempts to discard any data that |
777 | was previously read and buffered in C<OLD> before duping the handle. |
778 | On platforms where doing this is allowed, the next read operation |
779 | on C<NEW> will return the same data as the corresponding operation |
780 | on C<OLD>. Formerly, it would have returned the data from the start |
781 | of the following disk block instead. |
782 | |
783 | =head2 system(), backticks and pipe open now reflect exec() failure |
784 | |
785 | On Unix and similar platforms, system(), qx() and open(FOO, "cmd |") |
786 | etc., are implemented via fork() and exec(). When the underlying |
787 | exec() fails, earlier versions did not report the error properly, |
788 | since the exec() happened to be in a different process. |
789 | |
790 | The child process now communicates with the parent about the |
437784d6 |
791 | error in launching the external command, which allows these |
a5222a85 |
792 | constructs to return with their usual error value and set $!. |
793 | |
794 | =head2 Implicitly closed filehandles are safer |
795 | |
796 | Sometimes implicitly closed filehandles (as when they are localized, |
797 | and Perl automatically closes them on exiting the scope) could |
798 | inadvertently set $? or $!. This has been corrected. |
799 | |
800 | =head2 C<(\$)> prototype and C<$foo{a}> |
801 | |
802 | An scalar reference prototype now correctly allows a hash or |
803 | array element in that slot. |
804 | |
805 | =head2 Pseudo-hashes work better |
806 | |
807 | Dereferencing some types of reference values in a pseudo-hash, |
808 | such as C<$ph->{foo}[1]>, was accidentally disallowed. This has |
809 | been corrected. |
810 | |
811 | When applied to a pseudo-hash element, exists() now reports whether |
812 | the specified value exists, not merely if the key is valid. |
813 | |
814 | =head2 C<goto &sub> and AUTOLOAD |
815 | |
08cd8952 |
816 | The C<goto &sub> construct works correctly when C<&sub> happens |
a5222a85 |
817 | to be autoloaded. |
818 | |
819 | =head2 C<-bareword> allowed under C<use integer> |
820 | |
821 | The autoquoting of barewords preceded by C<-> did not work |
822 | in prior versions when the C<integer> pragma was enabled. |
823 | This has been fixed. |
824 | |
825 | =head2 Boolean assignment operators are legal lvalues |
826 | |
827 | Constructs such as C<($a ||= 2) += 1> are now allowed. |
828 | |
829 | =head2 C<sort $coderef @foo> allowed |
830 | |
831 | sort() did not accept a subroutine reference as the comparison |
08cd8952 |
832 | function in earlier versions. This is now permitted. |
a5222a85 |
833 | |
834 | =head2 Failures in DESTROY() |
835 | |
836 | When code in a destructor threw an exception, it went unnoticed |
837 | in earlier versions of Perl, unless someone happened to be |
838 | looking in $@ just after the point the destructor happened to |
839 | run. Such failures are now visible as warnings when warnings are |
840 | enabled. |
841 | |
842 | =head2 Locale bugs fixed |
54195c32 |
843 | |
437784d6 |
844 | printf() and sprintf() previously reset the numeric locale |
67d3893f |
845 | back to the default "C" locale. This has been fixed. |
846 | |
847 | Numbers formatted according to the local numeric locale |
848 | (such as using a decimal comma instead of a decimal dot) caused |
849 | "isn't numeric" warnings, even while the operations accessing |
850 | those numbers produced correct results. The warnings are gone. |
54195c32 |
851 | |
a5222a85 |
852 | =head2 Memory leaks |
853 | |
854 | The C<eval 'return sub {...}'> construct could sometimes leak |
855 | memory. This has been fixed. |
856 | |
857 | Operations that aren't filehandle constructors used to leak memory |
858 | when used on invalid filehandles. This has been fixed. |
859 | |
860 | Constructs that modified C<@_> could fail to deallocate values |
861 | in C<@_> and thus leak memory. This has been corrected. |
862 | |
863 | =head2 Spurious subroutine stubs after failed subroutine calls |
864 | |
865 | Perl could sometimes create empty subroutine stubs when a |
866 | subroutine was not found in the package. Such cases stopped |
867 | later method lookups from progressing into base packages. |
868 | This has been corrected. |
869 | |
870 | =head2 Consistent numeric conversions |
871 | |
872 | change#3378,3318 |
873 | [TODO - Ilya Zakharevich <ilya@math.ohio-state.edu>] |
874 | |
875 | =head2 Taint failures under C<-U> |
876 | |
877 | When running in unsafe mode, taint violations could sometimes |
878 | cause silent failures. This has been fixed. |
879 | |
880 | =head2 END blocks and the C<-c> switch |
881 | |
882 | Prior versions used to run BEGIN B<and> END blocks when Perl was |
883 | run in compile-only mode. Since this is typically not the expected |
08cd8952 |
884 | behavior, END blocks are not executed anymore when the C<-c> switch |
a5222a85 |
885 | is used. |
886 | |
4f25aa18 |
887 | See L<STOP blocks> for how to run things when the compile phase ends. |
a5222a85 |
888 | |
889 | =head2 Potential to leak DATA filehandles |
890 | |
891 | Using the C<__DATA__> token creates an implicit filehandle to |
892 | the file that contains the token. It is the program's |
893 | responsibility to close it when it is done reading from it. |
894 | |
895 | This caveat is now better explained in the documentation. |
896 | See L<perldata>. |
897 | |
898 | =head2 Diagnostics follow STDERR |
899 | |
900 | Diagnostic output now goes to whichever file the C<STDERR> handle |
901 | is pointing at, instead of always going to the underlying C runtime |
902 | library's C<stderr>. |
903 | |
904 | =head2 Other fixes for better diagnostics |
905 | |
437784d6 |
906 | Line numbers are no longer suppressed (under most likely circumstances) |
a5222a85 |
907 | during the global destruction phase. |
908 | |
909 | Diagnostics emitted from code running in threads other than the main |
910 | thread are now accompanied by the thread ID. |
911 | |
912 | Embedded null characters in diagnostics now actually show up. They |
913 | used to truncate the message in prior versions. |
914 | |
915 | $foo::a and $foo::b are now exempt from "possible typo" warnings only |
916 | if sort() is encountered in package foo. |
917 | |
501fbaef |
918 | Unrecognized alphabetic escapes encountered when parsing quote |
a5222a85 |
919 | constructs now generate a warning, since they may take on new |
920 | semantics in later versions of Perl. |
921 | |
922 | =head1 Performance enhancements |
923 | |
924 | =head2 Simple sort() using { $a <=> $b } and the like are optimized |
925 | |
08cd8952 |
926 | Many common sort() operations using a simple inlined block are now |
a5222a85 |
927 | optimized for faster performance. |
928 | |
929 | =head2 Optimized assignments to lexical variables |
930 | |
931 | Certain operations in the RHS of assignment statements have been |
932 | optimized to directly set the lexical variable on the LHS, |
933 | eliminating redundant copying overheads. |
934 | |
935 | =head2 Method lookups optimized |
936 | |
937 | [TODO - Chip Salzenberg <chip@perlsupport.com>] |
938 | |
939 | =head2 Faster mechanism to invoke XSUBs |
940 | |
941 | change#4044,4125 |
942 | [TODO - Ilya Zakharevich <ilya@math.ohio-state.edu>] |
943 | |
944 | =head2 Perl_malloc() improvements |
945 | |
946 | change#4237 |
947 | [TODO - Ilya Zakharevich <ilya@math.ohio-state.edu>] |
948 | |
949 | =head2 Faster subroutine calls |
950 | |
951 | Minor changes in how subroutine calls are handled internally |
952 | provide marginal improvements in performance. |
953 | |
954 | =head1 Platform specific changes |
955 | |
956 | =head2 Additional supported platforms |
ba8251e8 |
957 | |
5fdc711f |
958 | =over 4 |
959 | |
960 | =item * |
961 | |
6c67e1bb |
962 | VM/ESA is now supported. |
963 | |
5fdc711f |
964 | =item * |
965 | |
ee3907e2 |
966 | Siemens BS2000 is now supported under the POSIX Shell. |
967 | |
968 | =item * |
969 | |
2bb14304 |
970 | The Mach CThreads (NEXTSTEP, OPENSTEP) are now supported by the Thread |
971 | extension. |
6c67e1bb |
972 | |
5fdc711f |
973 | =item * |
974 | |
ee3907e2 |
975 | GNU/Hurd is now supported. |
6c67e1bb |
976 | |
00ad96e1 |
977 | =item * |
978 | |
979 | Rhapsody is now supported. |
980 | |
27806c82 |
981 | =item * |
982 | |
983 | EPOC is is now supported (on Psion 5). |
984 | |
5fdc711f |
985 | =back |
986 | |
a5222a85 |
987 | =head2 DOS |
988 | |
d524f05e |
989 | =over 4 |
990 | |
991 | =item * |
992 | |
993 | Perl now works with djgpp 2.02 (and 2.03 alpha). |
994 | |
995 | =item * |
996 | |
997 | Environment variable names are not converted to uppercase any more. |
998 | |
999 | =item * |
1000 | |
1001 | Wrong exit code from backticks now fixed. |
1002 | |
1003 | =item * |
1004 | |
1005 | This port is still using its own builtin globbing. |
1006 | |
1007 | =back |
a5222a85 |
1008 | |
1009 | =head2 OS/2 |
1010 | |
1011 | [TODO - Ilya Zakharevich <ilya@math.ohio-state.edu>] |
1012 | |
1013 | =head2 VMS |
1014 | |
1015 | [TODO - Charles Bailey <bailey@newman.upenn.edu>] |
1016 | |
1017 | =head2 Win32 |
1018 | |
1019 | Site library searches failed to look for ".../site/5.XXX/lib" |
1020 | if ".../site/5.XXXYY/lib" wasn't found. This has been corrected. |
1021 | |
1022 | When given a pathname that consists only of a drivename, such |
1023 | as C<A:>, opendir() and stat() now use the current working |
1024 | directory for the drive rather than the drive root. |
1025 | |
1026 | The builtin XSUB functions in the Win32:: namespace are |
1027 | documented. See L<Win32>. |
1028 | |
1029 | $^X now contains the full path name of the running executable. |
1030 | |
1031 | A Win32::GetLongPathName() function is provided to complement |
1032 | Win32::GetFullPathName() and Win32::GetShortPathName(). See L<Win32>. |
1033 | |
1034 | POSIX::uname() is supported. |
1035 | |
1036 | system(1,...) now returns true process IDs rather than process |
1037 | handles. kill() accepts any real process id, rather than strictly |
1038 | return values from system(1,...). |
1039 | |
1040 | The C<Shell> module is supported. |
1041 | |
883d36a6 |
1042 | Rudimentary support for building under command.com in Windows 95 |
1043 | has been added. |
1044 | |
a5222a85 |
1045 | [TODO - GSAR] |
1046 | |
6c67e1bb |
1047 | =head1 New tests |
1048 | |
1049 | =over 4 |
1050 | |
09bef843 |
1051 | =item lib/attrs |
1052 | |
1053 | Compatibility tests for C<sub : attrs> vs the older C<use attrs>. |
1054 | |
1055 | =item lib/io_const |
6c67e1bb |
1056 | |
1057 | IO constants (SEEK_*, _IO*). |
14218588 |
1058 | |
09bef843 |
1059 | =item lib/io_dir |
6c67e1bb |
1060 | |
1061 | Directory-related IO methods (new, read, close, rewind, tied delete). |
1062 | |
09bef843 |
1063 | =item lib/io_multihomed |
6c67e1bb |
1064 | |
1065 | INET sockets with multi-homed hosts. |
1066 | |
09bef843 |
1067 | =item lib/io_poll |
6c67e1bb |
1068 | |
1069 | IO poll(). |
1070 | |
09bef843 |
1071 | =item lib/io_unix |
6c67e1bb |
1072 | |
1073 | UNIX sockets. |
1074 | |
09bef843 |
1075 | =item op/attrs |
1076 | |
1077 | Regression tests for C<my ($x,@y,%z) : attrs> and <sub : attrs>. |
1078 | |
6c67e1bb |
1079 | =item op/filetest |
1080 | |
1081 | File test operators. |
1082 | |
1083 | =item op/lex_assign |
1084 | |
5fdc711f |
1085 | Verify operations that access pad objects (lexicals and temporaries). |
6c67e1bb |
1086 | |
1087 | =back |
e02fdbd2 |
1088 | |
ba8251e8 |
1089 | =head1 Modules and Pragmata |
1090 | |
3e8c4fa0 |
1091 | =head2 Modules |
1092 | |
b7d8191e |
1093 | =over 4 |
1094 | |
09bef843 |
1095 | =item attributes |
1096 | |
1097 | While used internally by Perl as a pragma, this module also |
1098 | provides a way to fetch subroutine and variable attributes. |
1099 | See L<attributes>. |
1100 | |
a5222a85 |
1101 | =item B |
1102 | |
501fbaef |
1103 | The Perl Compiler suite has been extensively reworked for this |
1104 | release. |
1105 | |
a5222a85 |
1106 | [TODO - Vishal Bhatia <vishal@gol.com>, |
1107 | Nick Ing-Simmons <nick@ni-s.u-net.com>] |
1108 | |
f29c64d6 |
1109 | =item ByteLoader |
1110 | |
a5222a85 |
1111 | The ByteLoader is a dedicated extension to generate and run |
f29c64d6 |
1112 | Perl bytecode. See L<ByteLoader>. |
1113 | |
a5222a85 |
1114 | =item constant |
1115 | |
1116 | References can now be used. See L<constant>. |
1117 | |
1118 | =item charnames |
1119 | |
1120 | change#4052 |
1121 | [TODO - Ilya Zakharevich <ilya@math.ohio-state.edu>] |
1122 | |
1123 | =item Data::Dumper |
1124 | |
1125 | A C<Maxdepth> setting can be specified to avoid venturing |
73b437c8 |
1126 | too deeply into deep data structures. See L<Data::Dumper>. |
a5222a85 |
1127 | |
1128 | Dumping C<qr//> objects works correctly. |
1129 | |
1130 | =item DB |
1131 | |
1132 | C<DB> is an experimental module that exposes a clean abstraction |
1133 | to Perl's debugging API. |
1134 | |
1135 | =item DB_File |
1136 | |
1137 | [TODO - Paul Marquess <paul.marquess@bt.com>] |
1138 | |
f29c64d6 |
1139 | =item Devel::DProf |
1140 | |
9e107c59 |
1141 | Devel::DProf, a Perl source code profiler has been added. See |
1142 | L<Devel::DProf> and L<dprofpp>. |
f29c64d6 |
1143 | |
b7d8191e |
1144 | =item Dumpvalue |
1145 | |
437784d6 |
1146 | The Dumpvalue module provides screen dumps of Perl data. |
b7d8191e |
1147 | |
1148 | =item Benchmark |
1149 | |
54e82ce5 |
1150 | Overall, Benchmark results exhibit lower average error and better timing |
1151 | accuracy. |
1152 | |
868cb350 |
1153 | You can now run tests for I<n> seconds instead of guessing the right |
14218588 |
1154 | number of tests to run: e.g. timethese(-5, ...) will run each |
1155 | code for at least 5 CPU seconds. Zero as the "number of repetitions" |
155776c0 |
1156 | means "for at least 3 CPU seconds". The output format has also |
14218588 |
1157 | changed. For example: |
155776c0 |
1158 | |
54e82ce5 |
1159 | use Benchmark;$x=3;timethese(-5,{a=>sub{$x*$x},b=>sub{$x**2}}) |
155776c0 |
1160 | |
1161 | will now output something like this: |
1162 | |
54e82ce5 |
1163 | Benchmark: running a, b, each for at least 5 CPU seconds... |
1164 | a: 5 wallclock secs ( 5.77 usr + 0.00 sys = 5.77 CPU) @ 200551.91/s (n=1156516) |
1165 | b: 4 wallclock secs ( 5.00 usr + 0.02 sys = 5.02 CPU) @ 159605.18/s (n=800686) |
155776c0 |
1166 | |
1167 | New features: "each for at least N CPU seconds...", "wallclock secs", |
1168 | and the "@ operations/CPU second (n=operations)". |
b7d8191e |
1169 | |
54e82ce5 |
1170 | timethese() now returns a reference to a hash of Benchmark objects containing |
1171 | the test results, keyed on the names of the tests. |
1172 | |
1173 | timethis() now returns the iterations field in the Benchmark result object |
1174 | instead of 0. |
1175 | |
1176 | timethese(), timethis(), and the new cmpthese() (see below) can also take |
1177 | a format specifier of 'none' to suppress output. |
1178 | |
1179 | A new function countit() is just like timeit() except that it takes a |
1180 | TIME instead of a COUNT. |
1181 | |
1182 | A new function cmpthese() prints a chart comparing the results of each test |
1183 | returned from a timethese() call. For each possible pair of tests, the |
1184 | percentage speed difference (iters/sec or seconds/iter) is shown. |
1185 | |
1186 | For other details, see L<Benchmark>. |
a5222a85 |
1187 | |
f505c983 |
1188 | =item Devel::Peek |
1189 | |
1190 | The Devel::Peek module provides access to the internal representation |
14218588 |
1191 | of Perl variables and data. It is a data debugging tool for the XS programmer. |
f505c983 |
1192 | |
a5222a85 |
1193 | =item ExtUtils::MakeMaker |
1194 | |
1195 | change#4135, also needs docs in module pod |
1196 | [TODO - Ilya Zakharevich <ilya@math.ohio-state.edu>] |
1197 | |
b7d8191e |
1198 | =item Fcntl |
1199 | |
1200 | More Fcntl constants added: F_SETLK64, F_SETLKW64, O_LARGEFILE for |
14218588 |
1201 | large (more than 4G) file access (64-bit support is not yet |
b7d8191e |
1202 | working, though, so no need to get overly excited), Free/Net/OpenBSD |
1203 | locking behaviour flags F_FLOCK, F_POSIX, Linux F_SHLCK, and |
1204 | O_ACCMODE: the mask of O_RDONLY, O_WRONLY, and O_RDWR. |
1205 | |
a5222a85 |
1206 | =item File::Compare |
1207 | |
1208 | A compare_text() function has been added, which allows custom |
1209 | comparison functions. See L<File::Compare>. |
1210 | |
1211 | =item File::Find |
1212 | |
1213 | File::Find now works correctly when the wanted() function is either |
1214 | autoloaded or is a symbolic reference. |
1215 | |
08cd8952 |
1216 | A bug that caused File::Find to lose track of the working directory |
a5222a85 |
1217 | when pruning top-level directories has been fixed. |
1218 | |
81793b90 |
1219 | File::Find now also supports several other options to control its |
1220 | behavior. It can follow symbolic links if the C<follow> option is |
1221 | specified. Enabling the C<no_chdir> option will make File::Find skip |
1222 | changing the current directory when walking directories. The C<untaint> |
1223 | flag can be useful when running with taint checks enabled. |
1224 | |
1225 | See L<File::Find>. |
1226 | |
becf2bd3 |
1227 | =item File::Glob |
1228 | |
52bb0670 |
1229 | This extension implements BSD-style file globbing. By default, |
1230 | it will also be used for the internal implementation of the glob() |
1231 | operator. See L<File::Glob>. |
becf2bd3 |
1232 | |
f505c983 |
1233 | =item File::Spec |
1234 | |
1235 | New methods have been added to the File::Spec module: devnull() returns |
19799a22 |
1236 | the name of the null device (/dev/null on Unix) and tmpdir() the name of |
14218588 |
1237 | the temp directory (normally /tmp on Unix). There are now also methods |
f505c983 |
1238 | to convert between absolute and relative filenames: abs2rel() and |
14218588 |
1239 | rel2abs(). For compatibility with operating systems that specify volume |
1240 | names in file paths, the splitpath(), splitdir(), and catdir() methods |
f505c983 |
1241 | have been added. |
1242 | |
1243 | =item File::Spec::Functions |
1244 | |
1245 | The new File::Spec::Functions modules provides a function interface |
14218588 |
1246 | to the File::Spec module. Allows shorthand |
f505c983 |
1247 | |
14218588 |
1248 | $fullname = catfile($dir1, $dir2, $file); |
f505c983 |
1249 | |
1250 | instead of |
1251 | |
14218588 |
1252 | $fullname = File::Spec->catfile($dir1, $dir2, $file); |
f505c983 |
1253 | |
a5222a85 |
1254 | =item Getopt::Long |
1255 | |
c6edd1b7 |
1256 | Getopt::Long licensing has changed to allow the Perl Artistic License |
1257 | as well as the GPL. It used to be GPL only, which got in the way of |
1258 | non-GPL applications that wanted to use Getopt::Long. |
1259 | |
1260 | Getopt::Long encourages the use of Pod::Usage to produce help |
1261 | messages. For example: |
1262 | |
1263 | use Getopt::Long; |
1264 | use Pod::Usage; |
1265 | my $man = 0; |
1266 | my $help = 0; |
1267 | GetOptions('help|?' => \$help, man => \$man) or pod2usage(2); |
1268 | pod2usage(1) if $help; |
1269 | pod2usage(-exitstatus => 0, -verbose => 2) if $man; |
1270 | |
1271 | __END__ |
1272 | |
1273 | =head1 NAME |
1274 | |
1275 | sample - Using GetOpt::Long and Pod::Usage |
1276 | |
1277 | =head1 SYNOPSIS |
1278 | |
1279 | sample [options] [file ...] |
1280 | |
1281 | Options: |
1282 | -help brief help message |
1283 | -man full documentation |
1284 | |
1285 | =head1 OPTIONS |
1286 | |
1287 | =over 8 |
1288 | |
1289 | =item B<-help> |
1290 | |
1291 | Print a brief help message and exits. |
1292 | |
1293 | =item B<-man> |
1294 | |
1295 | Prints the manual page and exits. |
1296 | |
1297 | =back |
1298 | |
1299 | =head1 DESCRIPTION |
1300 | |
1301 | B<This program> will read the given input file(s) and do someting |
1302 | useful with the contents thereof. |
1303 | |
1304 | =cut |
1305 | |
1306 | See L<Pod::Usage> for details. |
1307 | |
1308 | A bug that prevented the non-option call-back E<lt>E<gt> from being |
1309 | specified as the first argument has been fixed. |
1310 | |
1311 | To specify the characters E<lt> and E<gt> as option starters, use |
1312 | E<gt>E<lt>. Note, however, that changing option starters is strongly |
1313 | deprecated. |
a5222a85 |
1314 | |
1315 | =item IO |
1316 | |
1317 | write() and syswrite() will now accept a single-argument |
1318 | form of the call, for consistency with Perl's syswrite(). |
1319 | |
1320 | You can now create a TCP-based IO::Socket::INET without forcing |
1321 | a connect attempt. This allows you to configure its options |
1322 | (like making it non-blocking) and then call connect() manually. |
1323 | |
1324 | A bug that prevented the IO::Socket::protocol() accessor |
1325 | from ever returning the correct value has been corrected. |
1326 | |
1327 | =item JPL |
1328 | |
1329 | Java Perl Lingo is now distributed with Perl. See jpl/README |
1330 | for more information. |
1331 | |
883d36a6 |
1332 | =item lib |
1333 | |
1334 | C<use lib> now weeds out any trailing duplicate entries. |
1335 | C<no lib> removes all named entries. |
1336 | |
e16b8f49 |
1337 | =item Math::BigInt |
1338 | |
437784d6 |
1339 | The bitwise operations C<E<lt>E<lt>>, C<E<gt>E<gt>>, C<&>, C<|>, |
e16b8f49 |
1340 | and C<~> are now supported on bigints. |
1341 | |
b7d8191e |
1342 | =item Math::Complex |
7711098a |
1343 | |
14218588 |
1344 | The accessor methods Re, Im, arg, abs, rho, and theta can now also |
868cb350 |
1345 | act as mutators (accessor $z->Re(), mutator $z->Re(3)). |
b7d8191e |
1346 | |
1347 | =item Math::Trig |
1348 | |
14218588 |
1349 | A little bit of radial trigonometry (cylindrical and spherical), |
1350 | radial coordinate conversions, and the great circle distance were added. |
b7d8191e |
1351 | |
a5222a85 |
1352 | =item Pod::Parser |
1353 | |
1354 | [TODO - Brad Appleton <bradapp@enteract.com>] |
1355 | |
1356 | =item Pod::Text and Pod::Man |
1357 | |
1358 | [TODO - Russ Allbery <rra@stanford.edu>] |
1359 | |
f4b9d880 |
1360 | =item SDBM_File |
1361 | |
1362 | An EXISTS method has been added to this module (and sdbm_exists() has |
1363 | been added to the underlying sdbm library), so one can now call exists |
14218588 |
1364 | on an SDBM_File tied hash and get the correct result, rather than a |
f4b9d880 |
1365 | runtime error. |
1366 | |
a5222a85 |
1367 | A bug that may have caused data loss when more than one disk block |
1368 | happens to be read from the database in a single FETCH() has been |
1369 | fixed. |
1370 | |
06ef4121 |
1371 | =item Time::Local |
1372 | |
1373 | The timelocal() and timegm() functions used to silently return bogus |
437784d6 |
1374 | results when the date fell outside the machine's integer range. They |
a5222a85 |
1375 | now consistently croak() if the date falls in an unsupported range. |
06ef4121 |
1376 | |
8fe0a5c4 |
1377 | =item Win32 |
1378 | |
1379 | The error return value in list context has been changed for all functions |
14218588 |
1380 | that return a list of values. Previously these functions returned a list |
1381 | with a single element C<undef> if an error occurred. Now these functions |
1382 | return the empty list in these situations. This applies to the following |
8fe0a5c4 |
1383 | functions: |
1384 | |
14218588 |
1385 | Win32::FsType |
1386 | Win32::GetOSVersion |
8fe0a5c4 |
1387 | |
1388 | The remaining functions are unchanged and continue to return C<undef> on |
1389 | error even in list context. |
1390 | |
1391 | The Win32::SetLastError(ERROR) function has been added as a complement |
1392 | to the Win32::GetLastError() function. |
1393 | |
1394 | The new Win32::GetFullPathName(FILENAME) returns the full absolute |
14218588 |
1395 | pathname for FILENAME in scalar context. In list context it returns |
1396 | a two-element list containing the fully qualified directory name and |
501fbaef |
1397 | the filename. See L<Win32>. |
8fe0a5c4 |
1398 | |
9fe6733a |
1399 | =item DBM Filters |
1400 | |
1401 | A new feature called "DBM Filters" has been added to all the |
14218588 |
1402 | DBM modules--DB_File, GDBM_File, NDBM_File, ODBM_File, and SDBM_File. |
1403 | DBM Filters add four new methods to each DBM module: |
9fe6733a |
1404 | |
1405 | filter_store_key |
1406 | filter_store_value |
1407 | filter_fetch_key |
1408 | filter_fetch_value |
1409 | |
14218588 |
1410 | These can be used to filter key-value pairs before the pairs are |
9fe6733a |
1411 | written to the database or just after they are read from the database. |
1412 | See L<perldbmfilter> for further information. |
1413 | |
b7d8191e |
1414 | =back |
3e8c4fa0 |
1415 | |
1416 | =head2 Pragmata |
1417 | |
437784d6 |
1418 | C<use attrs> is now obsolete, and is only provided for |
09bef843 |
1419 | backward-compatibility. It's been replaced by the C<sub : attributes> |
1420 | syntax. See L<perlsub/"Subroutine Attributes"> and L<attributes>. |
1421 | |
14218588 |
1422 | C<use utf8> to enable UTF-8 and Unicode support. |
43165c05 |
1423 | |
1424 | C<use caller 'encoding'> allows modules to inherit pragmatic attributes |
1425 | from the caller's context. C<encoding> is currently the only supported |
1426 | attribute. |
9d73390d |
1427 | |
4438c4b7 |
1428 | Lexical warnings pragma, C<use warnings;>, to control optional warnings. |
a5222a85 |
1429 | See L<perllexwarn>. |
6c67e1bb |
1430 | |
67d3893f |
1431 | C<use filetest> to control the behaviour of filetests (C<-r> C<-w> |
1432 | ...). Currently only one subpragma implemented, "use filetest |
1433 | 'access';", that uses access(2) or equivalent to check permissions |
1434 | instead of using stat(2) as usual. This matters in filesystems |
1435 | where there are ACLs (access control lists): the stat(2) might lie, |
1436 | but access(2) knows better. |
6c67e1bb |
1437 | |
ba8251e8 |
1438 | =head1 Utility Changes |
1439 | |
a5222a85 |
1440 | =head2 h2ph |
1441 | |
1442 | [TODO - Kurt Starsinic <kstar@chapin.edu>] |
1443 | |
1444 | =head2 perlcc |
1445 | |
1446 | C<perlcc> now supports the C and Bytecode backends. By default, |
1447 | it generates output from the simple C backend rather than the |
1448 | optimized C backend. |
1449 | |
1450 | Support for non-Unix platforms has been improved. |
1451 | |
1452 | =head2 h2xs |
1453 | |
1454 | change#4232 |
1455 | [TODO - Ilya Zakharevich <ilya@math.ohio-state.edu>] |
e02fdbd2 |
1456 | |
ba8251e8 |
1457 | =head1 Documentation Changes |
1458 | |
5fdc711f |
1459 | =over 4 |
1460 | |
883d36a6 |
1461 | =item perlcompile.pod |
1462 | |
1463 | An introduction to using the Perl Compiler suite. |
1464 | |
c7c04614 |
1465 | =item perlfilter.pod |
1466 | |
1467 | An introduction to writing Perl source filters. |
1468 | |
883d36a6 |
1469 | =item perlhack.pod |
1470 | |
1471 | Some guidelines for hacking the Perl source code. |
1472 | |
5fdc711f |
1473 | =item perlopentut.pod |
f8284313 |
1474 | |
5fdc711f |
1475 | A tutorial on using open() effectively. |
1476 | |
1477 | =item perlreftut.pod |
1478 | |
1479 | A tutorial that introduces the essentials of references. |
1480 | |
14218588 |
1481 | =item perltootc.pod |
1482 | |
1483 | A tutorial on managing class data for object modules. |
1484 | |
5fdc711f |
1485 | =back |
e02fdbd2 |
1486 | |
73b437c8 |
1487 | =head1 New or Changed Diagnostics |
ba8251e8 |
1488 | |
a99ba403 |
1489 | =over 4 |
1490 | |
09bef843 |
1491 | =item "my sub" not yet implemented |
1492 | |
1493 | (F) Lexically scoped subroutines are not yet implemented. Don't try that |
1494 | yet. |
1495 | |
a99ba403 |
1496 | =item '!' allowed only after types %s |
1497 | |
1498 | (F) The '!' is allowed in pack() and unpack() only after certain types. |
1499 | See L<perlfunc/pack>. |
1500 | |
1501 | =item / cannot take a count |
1502 | |
1503 | (F) You had an unpack template indicating a counted-length string, |
1504 | but you have also specified an explicit size for the string. |
1505 | See L<perlfunc/pack>. |
1506 | |
1507 | =item / must be followed by a, A or Z |
1508 | |
1509 | (F) You had an unpack template indicating a counted-length string, |
1510 | which must be followed by one of the letters a, A or Z |
1511 | to indicate what sort of string is to be unpacked. |
1512 | See L<perlfunc/pack>. |
1513 | |
1514 | =item / must be followed by a*, A* or Z* |
1515 | |
437784d6 |
1516 | (F) You had a pack template indicating a counted-length string, |
a99ba403 |
1517 | Currently the only things that can have their length counted are a*, A* or Z*. |
1518 | See L<perlfunc/pack>. |
1519 | |
1520 | =item / must follow a numeric type |
1521 | |
1522 | (F) You had an unpack template that contained a '#', |
1523 | but this did not follow some numeric unpack specification. |
1524 | See L<perlfunc/pack>. |
1525 | |
a99ba403 |
1526 | =item /%s/: Unrecognized escape \\%c passed through |
1527 | |
1528 | (W) You used a backslash-character combination which is not recognized |
1529 | by Perl. This combination appears in an interpolated variable or a |
1028017a |
1530 | C<'>-delimited regular expression. The character was understood literally. |
1531 | |
1532 | =item /%s/: Unrecognized escape \\%c in character class passed through |
1533 | |
1534 | (W) You used a backslash-character combination which is not recognized |
1535 | by Perl inside character classes. The character was understood literally. |
a99ba403 |
1536 | |
1537 | =item /%s/ should probably be written as "%s" |
1538 | |
1539 | (W) You have used a pattern where Perl expected to find a string, |
437784d6 |
1540 | as in the first argument to C<join>. Perl will treat the true |
a99ba403 |
1541 | or false result of matching the pattern against $_ as the string, |
1542 | which is probably not what you had in mind. |
1543 | |
1544 | =item %s() called too early to check prototype |
1545 | |
1546 | (W) You've called a function that has a prototype before the parser saw a |
1547 | definition or declaration for it, and Perl could not check that the call |
1548 | conforms to the prototype. You need to either add an early prototype |
1549 | declaration for the subroutine in question, or move the subroutine |
1550 | definition ahead of the call to get proper prototype checking. Alternatively, |
1551 | if you are certain that you're calling the function correctly, you may put |
1552 | an ampersand before the name to avoid the warning. See L<perlsub>. |
1553 | |
09bef843 |
1554 | =item %s package attribute may clash with future reserved word: %s |
1555 | |
1556 | (W) A lowercase attribute name was used that had a package-specific handler. |
1557 | That name might have a meaning to Perl itself some day, even though it |
1558 | doesn't yet. Perhaps you should use a mixed-case attribute name, instead. |
1559 | See L<attributes>. |
1560 | |
a99ba403 |
1561 | =item (in cleanup) %s |
6b121555 |
1562 | |
a99ba403 |
1563 | (W) This prefix usually indicates that a DESTROY() method raised |
1564 | the indicated exception. Since destructors are usually called by |
1565 | the system at arbitrary points during execution, and often a vast |
1566 | number of times, the warning is issued only once for any number |
1567 | of failures that would otherwise result in the same message being |
1568 | repeated. |
1569 | |
1570 | Failure of user callbacks dispatched using the C<G_KEEPERR> flag |
1571 | could also result in this warning. See L<perlcall/G_KEEPERR>. |
1572 | |
1573 | =item <> should be quotes |
1574 | |
1575 | (F) You wrote C<require E<lt>fileE<gt>> when you should have written |
1576 | C<require 'file'>. |
1577 | |
1578 | =item Attempt to join self |
1579 | |
1580 | (F) You tried to join a thread from within itself, which is an |
1581 | impossible task. You may be joining the wrong thread, or you may |
1582 | need to move the join() to some other thread. |
1583 | |
1584 | =item Bad evalled substitution pattern |
1585 | |
1586 | (F) You've used the /e switch to evaluate the replacement for a |
1587 | substitution, but perl found a syntax error in the code to evaluate, |
1588 | most likely an unexpected right brace '}'. |
1589 | |
1590 | =item Bad realloc() ignored |
1591 | |
1592 | (S) An internal routine called realloc() on something that had never been |
1593 | malloc()ed in the first place. Mandatory, but can be disabled by |
1594 | setting environment variable C<PERL_BADFREE> to 1. |
1595 | |
1596 | =item Binary number > 0b11111111111111111111111111111111 non-portable |
1597 | |
1598 | (W) The binary number you specified is larger than 2**32-1 |
1599 | (4294967295) and therefore non-portable between systems. See |
1600 | L<perlport> for more on portability concerns. |
1601 | |
1602 | =item Bit vector size > 32 non-portable |
1603 | |
1604 | (W) Using bit vector sizes larger than 32 is non-portable. |
1605 | |
1606 | =item Buffer overflow in prime_env_iter: %s |
1607 | |
1608 | (W) A warning peculiar to VMS. While Perl was preparing to iterate over |
1609 | %ENV, it encountered a logical name or symbol definition which was too long, |
1610 | so it was truncated to the string shown. |
1611 | |
1612 | =item Can't check filesystem of script "%s" |
1613 | |
1614 | (P) For some reason you can't check the filesystem of the script for nosuid. |
1615 | |
0b5b802d |
1616 | =item Can't ignore signal CHLD, forcing to default |
1617 | |
1618 | (W) Perl has detected that it is being run with the SIGCHLD signal |
1619 | (sometimes known as SIGCLD) disabled. Since disabling this signal |
1620 | will interfere with proper determination of exit status of child |
1621 | processes, Perl has reset the signal to its default value. |
1622 | This situation typically indicates that the parent program under |
1623 | which Perl may be running (e.g. cron) is being very careless. |
1624 | |
a99ba403 |
1625 | =item Can't modify non-lvalue subroutine call |
1626 | |
437784d6 |
1627 | (F) Subroutines meant to be used in lvalue context should be declared as |
1628 | such, see L<perlsub/"Lvalue subroutines">. |
a99ba403 |
1629 | |
1630 | =item Can't read CRTL environ |
1631 | |
1632 | (S) A warning peculiar to VMS. Perl tried to read an element of %ENV |
1633 | from the CRTL's internal environment array and discovered the array was |
1634 | missing. You need to figure out where your CRTL misplaced its environ |
1635 | or define F<PERL_ENV_TABLES> (see L<perlvms>) so that environ is not searched. |
1636 | |
1637 | =item Can't remove %s: %s, skipping file |
1638 | |
1639 | (S) You requested an inplace edit without creating a backup file. Perl |
1640 | was unable to remove the original file to replace it with the modified |
1641 | file. The file was left unmodified. |
1642 | |
1643 | =item Can't return %s from lvalue subroutine |
1644 | |
1645 | (F) Perl detected an attempt to return illegal lvalues (such |
1646 | as temporary or readonly values) from a subroutine used as an lvalue. |
1647 | This is not allowed. |
1648 | |
1649 | =item Can't weaken a nonreference |
1650 | |
1651 | (F) You attempted to weaken something that was not a reference. Only |
1652 | references can be weakened. |
1653 | |
1654 | =item Character class [:%s:] unknown |
1655 | |
1656 | (F) The class in the character class [: :] syntax is unknown. |
437784d6 |
1657 | See L<perlre>. |
a99ba403 |
1658 | |
1659 | =item Character class syntax [%s] belongs inside character classes |
1660 | |
1661 | (W) The character class constructs [: :], [= =], and [. .] go |
1662 | I<inside> character classes, the [] are part of the construct, |
437784d6 |
1663 | for example: /[012[:alpha:]345]/. Note that [= =] and [. .] |
1664 | are not currently implemented; they are simply placeholders for |
1665 | future extensions. |
a99ba403 |
1666 | |
1667 | =item Constant is not %s reference |
1668 | |
1669 | (F) A constant value (perhaps declared using the C<use constant> pragma) |
1670 | is being dereferenced, but it amounts to the wrong type of reference. The |
1671 | message indicates the type of reference that was expected. This usually |
1672 | indicates a syntax error in dereferencing the constant value. |
1673 | See L<perlsub/"Constant Functions"> and L<constant>. |
1674 | |
1675 | =item constant(%s): %%^H is not localized |
1676 | |
1677 | (F) When setting compile-time-lexicalized hash %^H one should set the |
1678 | corresponding bit of $^H as well. |
1679 | |
1680 | =item constant(%s): %s |
1681 | |
1682 | (F) Compile-time-substitutions (such as overloaded constants and |
1683 | character names) were not correctly set up. |
1684 | |
1685 | =item defined(@array) is deprecated |
1686 | |
1687 | (D) defined() is not usually useful on arrays because it checks for an |
1688 | undefined I<scalar> value. If you want to see if the array is empty, |
1689 | just use C<if (@array) { # not empty }> for example. |
1690 | |
1691 | =item defined(%hash) is deprecated |
1692 | |
1693 | (D) defined() is not usually useful on hashes because it checks for an |
1694 | undefined I<scalar> value. If you want to see if the hash is empty, |
1695 | just use C<if (%hash) { # not empty }> for example. |
1696 | |
1697 | =item Did not produce a valid header |
1698 | |
1699 | See Server error. |
1700 | |
1701 | =item Document contains no data |
1702 | |
1703 | See Server error. |
1704 | |
1705 | =item entering effective %s failed |
1706 | |
1707 | (F) While under the C<use filetest> pragma, switching the real and |
1708 | effective uids or gids failed. |
6b121555 |
1709 | |
73b437c8 |
1710 | =item false [] range "%s" in regexp |
1711 | |
1712 | (W) A character class range must start and end at a literal character, not |
1713 | another character class like C<\d> or C<[:alpha:]>. The "-" in your false |
1714 | range is interpreted as a literal "-". Consider quoting the "-", "\-". |
1715 | See L<perlre>. |
1716 | |
af8c498a |
1717 | =item Filehandle %s opened only for output |
6b121555 |
1718 | |
af8c498a |
1719 | (W) You tried to read from a filehandle opened only for writing. If you |
437784d6 |
1720 | intended it to be a read/write filehandle, you needed to open it with |
af8c498a |
1721 | "+E<lt>" or "+E<gt>" or "+E<gt>E<gt>" instead of with "E<lt>" or nothing. If |
1722 | you intended only to read from the file, use "E<lt>". See |
1723 | L<perlfunc/open>. |
e02fdbd2 |
1724 | |
a99ba403 |
1725 | =item Hexadecimal number > 0xffffffff non-portable |
1726 | |
1727 | (W) The hexadecimal number you specified is larger than 2**32-1 |
1728 | (4294967295) and therefore non-portable between systems. See |
1729 | L<perlport> for more on portability concerns. |
1730 | |
1731 | =item Ill-formed CRTL environ value "%s" |
1732 | |
1733 | (W) A warning peculiar to VMS. Perl tried to read the CRTL's internal |
1734 | environ array, and encountered an element without the C<=> delimiter |
1735 | used to spearate keys from values. The element is ignored. |
1736 | |
1737 | =item Ill-formed message in prime_env_iter: |%s| |
1738 | |
1739 | (W) A warning peculiar to VMS. Perl tried to read a logical name |
1740 | or CLI symbol definition when preparing to iterate over %ENV, and |
1741 | didn't see the expected delimiter between key and value, so the |
1742 | line was ignored. |
1743 | |
1744 | =item Illegal binary digit %s |
1745 | |
437784d6 |
1746 | (F) You used a digit other than 0 or 1 in a binary number. |
a99ba403 |
1747 | |
1748 | =item Illegal binary digit %s ignored |
1749 | |
1750 | (W) You may have tried to use a digit other than 0 or 1 in a binary number. |
1751 | Interpretation of the binary number stopped before the offending digit. |
1752 | |
1753 | =item Illegal number of bits in vec |
1754 | |
1755 | (F) The number of bits in vec() (the third argument) must be a power of |
1756 | two from 1 to 32 (or 64, if your platform supports that). |
1757 | |
1758 | =item Integer overflow in %s number |
1759 | |
1760 | (W) The hexadecimal, octal or binary number you have specified either |
c6edd1b7 |
1761 | as a literal or as an argument to hex() or oct() is too big for your |
a99ba403 |
1762 | architecture, and has been converted to a floating point number. On a |
1763 | 32-bit architecture the largest hexadecimal, octal or binary number |
1764 | representable without overflow is 0xFFFFFFFF, 037777777777, or |
1765 | 0b11111111111111111111111111111111 respectively. Note that Perl |
1766 | transparently promotes all numbers to a floating point representation |
1767 | internally--subject to loss of precision errors in subsequent |
1768 | operations. |
1769 | |
09bef843 |
1770 | =item Invalid %s attribute: %s |
1771 | |
1772 | The indicated attribute for a subroutine or variable was not recognized |
1773 | by Perl or by a user-supplied handler. See L<attributes>. |
1774 | |
1775 | =item Invalid %s attributes: %s |
1776 | |
1777 | The indicated attributes for a subroutine or variable were not recognized |
1778 | by Perl or by a user-supplied handler. See L<attributes>. |
1779 | |
73b437c8 |
1780 | =item invalid [] range "%s" in regexp |
1781 | |
1782 | The offending range is now explicitly displayed. |
1783 | |
09bef843 |
1784 | =item Invalid separator character %s in attribute list |
1785 | |
1786 | (F) Something other than a comma or whitespace was seen between the |
1787 | elements of an attribute list. If the previous attribute |
1788 | had a parenthesised parameter list, perhaps that list was terminated |
1789 | too soon. See L<attributes>. |
1790 | |
a99ba403 |
1791 | =item Invalid separator character %s in subroutine attribute list |
1792 | |
1793 | (F) Something other than a comma or whitespace was seen between the |
1794 | elements of a subroutine attribute list. If the previous attribute |
1795 | had a parenthesised parameter list, perhaps that list was terminated |
1796 | too soon. |
1797 | |
1798 | =item leaving effective %s failed |
1799 | |
1800 | (F) While under the C<use filetest> pragma, switching the real and |
1801 | effective uids or gids failed. |
1802 | |
1803 | =item Lvalue subs returning %s not implemented yet |
1804 | |
1805 | (F) Due to limitations in the current implementation, array and hash |
1806 | values cannot be returned in subroutines used in lvalue context. |
1807 | See L<perlsub/"Lvalue subroutines">. |
1808 | |
1809 | =item Method %s not permitted |
1810 | |
1811 | See Server error. |
1812 | |
1813 | =item Missing %sbrace%s on \N{} |
1814 | |
1815 | (F) Wrong syntax of character name literal C<\N{charname}> within |
1816 | double-quotish context. |
1817 | |
06eaf0bc |
1818 | =item Missing command in piped open |
1819 | |
1820 | (W) You used the C<open(FH, "| command")> or C<open(FH, "command |")> |
1821 | construction, but the command was missing or blank. |
1822 | |
09bef843 |
1823 | =item Missing name in "my sub" |
1824 | |
1825 | (F) The reserved syntax for lexically scoped subroutines requires that they |
1826 | have a name with which they can be found. |
1827 | |
a99ba403 |
1828 | =item no UTC offset information; assuming local time is UTC |
1829 | |
1830 | (S) A warning peculiar to VMS. Perl was unable to find the local |
1831 | timezone offset, so it's assuming that local system time is equivalent |
1832 | to UTC. If it's not, define the logical name F<SYS$TIMEZONE_DIFFERENTIAL> |
1833 | to translate to the number of seconds which need to be added to UTC to |
1834 | get local time. |
1835 | |
1836 | =item Octal number > 037777777777 non-portable |
1837 | |
1838 | (W) The octal number you specified is larger than 2**32-1 (4294967295) |
1839 | and therefore non-portable between systems. See L<perlport> for more |
1840 | on portability concerns. |
1841 | |
1842 | See also L<perlport> for writing portable code. |
1843 | |
1844 | =item panic: del_backref |
1845 | |
1846 | (P) Failed an internal consistency check while trying to reset a weak |
1847 | reference. |
1848 | |
1849 | =item panic: kid popen errno read |
1850 | |
1851 | (F) forked child returned an incomprehensible message about its errno. |
1852 | |
1853 | =item panic: magic_killbackrefs |
1854 | |
1855 | (P) Failed an internal consistency check while trying to reset all weak |
1856 | references to an object. |
1857 | |
1858 | =item Possible Y2K bug: %s |
1859 | |
1860 | (W) You are concatenating the number 19 with another number, which |
1861 | could be a potential Year 2000 problem. |
1862 | |
1863 | =item Premature end of script headers |
1864 | |
1865 | See Server error. |
1866 | |
0b5b802d |
1867 | =item Repeat count in pack overflows |
1868 | |
1869 | (F) You can't specify a repeat count so large that it overflows |
1870 | your signed integers. See L<perlfunc/pack>. |
1871 | |
1872 | =item Repeat count in unpack overflows |
1873 | |
1874 | (F) You can't specify a repeat count so large that it overflows |
1875 | your signed integers. See L<perlfunc/unpack>. |
1876 | |
a99ba403 |
1877 | =item realloc() of freed memory ignored |
1878 | |
1879 | (S) An internal routine called realloc() on something that had already |
1880 | been freed. |
1881 | |
1882 | =item Reference is already weak |
1883 | |
1884 | (W) You have attempted to weaken a reference that is already weak. |
1885 | Doing so has no effect. |
1886 | |
1887 | =item setpgrp can't take arguments |
1888 | |
1889 | (F) Your system has the setpgrp() from BSD 4.2, which takes no arguments, |
1890 | unlike POSIX setpgid(), which takes a process ID and process group ID. |
1891 | |
1892 | =item Strange *+?{} on zero-length expression |
1893 | |
1894 | (W) You applied a regular expression quantifier in a place where it |
1895 | makes no sense, such as on a zero-width assertion. |
1896 | Try putting the quantifier inside the assertion instead. For example, |
1897 | the way to match "abc" provided that it is followed by three |
1898 | repetitions of "xyz" is C</abc(?=(?:xyz){3})/>, not C</abc(?=xyz){3}/>. |
1899 | |
1900 | =item switching effective %s is not implemented |
1901 | |
1902 | (F) While under the C<use filetest> pragma, we cannot switch the |
1903 | real and effective uids or gids. |
1904 | |
437784d6 |
1905 | =item This Perl can't reset CRTL environ elements (%s) |
a99ba403 |
1906 | |
1907 | =item This Perl can't set CRTL environ elements (%s=%s) |
1908 | |
1909 | (W) Warnings peculiar to VMS. You tried to change or delete an element |
1910 | of the CRTL's internal environ array, but your copy of Perl wasn't |
1911 | built with a CRTL that contained the setenv() function. You'll need to |
1912 | rebuild Perl with a CRTL that does, or redefine F<PERL_ENV_TABLES> (see |
1913 | L<perlvms>) so that the environ array isn't the target of the change to |
1914 | %ENV which produced the warning. |
1915 | |
1916 | =item Unknown open() mode '%s' |
1917 | |
437784d6 |
1918 | (F) The second argument of 3-argument open() is not among the list |
1919 | of valid modes: C<L<lt>>, C<L<gt>>, C<E<gt>E<gt>>, C<+L<lt>>, |
1920 | C<+L<gt>>, C<+E<gt>E<gt>>, C<-|>, C<|->. |
a99ba403 |
1921 | |
1922 | =item Unknown process %x sent message to prime_env_iter: %s |
1923 | |
1924 | (P) An error peculiar to VMS. Perl was reading values for %ENV before |
1925 | iterating over it, and someone else stuck a message in the stream of |
1926 | data Perl expected. Someone's very confused, or perhaps trying to |
1927 | subvert Perl's population of %ENV for nefarious purposes. |
1928 | |
af8c498a |
1929 | =item Unrecognized escape \\%c passed through |
1930 | |
1931 | (W) You used a backslash-character combination which is not recognized |
1028017a |
1932 | by Perl. The character was understood literally. |
af8c498a |
1933 | |
09bef843 |
1934 | =item Unterminated attribute parameter in attribute list |
1935 | |
1936 | (F) The lexer saw an opening (left) parenthesis character while parsing an |
1937 | attribute list, but the matching closing (right) parenthesis |
1938 | character was not found. You may need to add (or remove) a backslash |
1939 | character to get your parentheses to balance. See L<attributes>. |
1940 | |
1941 | =item Unterminated attribute list |
1942 | |
1943 | (F) The lexer found something other than a simple identifier at the start |
1944 | of an attribute, and it wasn't a semicolon or the start of a |
1945 | block. Perhaps you terminated the parameter list of the previous attribute |
1946 | too soon. See L<attributes>. |
1947 | |
09bef843 |
1948 | =item Unterminated attribute parameter in subroutine attribute list |
1949 | |
1950 | (F) The lexer saw an opening (left) parenthesis character while parsing a |
1951 | subroutine attribute list, but the matching closing (right) parenthesis |
1952 | character was not found. You may need to add (or remove) a backslash |
1953 | character to get your parentheses to balance. |
1954 | |
1955 | =item Unterminated subroutine attribute list |
1956 | |
1957 | (F) The lexer found something other than a simple identifier at the start |
1958 | of a subroutine attribute, and it wasn't a semicolon or the start of a |
1959 | block. Perhaps you terminated the parameter list of the previous attribute |
1960 | too soon. |
1961 | |
a99ba403 |
1962 | =item Value of CLI symbol "%s" too long |
eb6e2d6f |
1963 | |
a99ba403 |
1964 | (W) A warning peculiar to VMS. Perl tried to read the value of an %ENV |
1965 | element from a CLI symbol table, and found a resultant string longer |
1966 | than 1024 characters. The return value has been truncated to 1024 |
1967 | characters. |
eb6e2d6f |
1968 | |
a99ba403 |
1969 | =item Version number must be a constant number |
ba8251e8 |
1970 | |
a99ba403 |
1971 | (P) The attempt to translate a C<use Module n.n LIST> statement into |
1972 | its equivalent C<BEGIN> block found an internal inconsistency with |
1973 | the version number. |
1974 | |
1975 | =back |
27806c82 |
1976 | |
a5222a85 |
1977 | =head1 Obsolete Diagnostics |
3175b8cd |
1978 | |
a99ba403 |
1979 | =over 4 |
1980 | |
1981 | =item Character class syntax [: :] is reserved for future extensions |
1982 | |
1983 | (W) Within regular expression character classes ([]) the syntax beginning |
1984 | with "[:" and ending with ":]" is reserved for future extensions. |
1985 | If you need to represent those character sequences inside a regular |
1986 | expression character class, just quote the square brackets with the |
1987 | backslash: "\[:" and ":\]". |
1988 | |
1989 | =item Ill-formed logical name |%s| in prime_env_iter |
1990 | |
1991 | (W) A warning peculiar to VMS. A logical name was encountered when preparing |
1992 | to iterate over %ENV which violates the syntactic rules governing logical |
1993 | names. Because it cannot be translated normally, it is skipped, and will not |
1994 | appear in %ENV. This may be a benign occurrence, as some software packages |
1995 | might directly modify logical name tables and introduce nonstandard names, |
1996 | or it may indicate that a logical name table has been corrupted. |
1997 | |
1998 | =item regexp too big |
1999 | |
2000 | (F) The current implementation of regular expressions uses shorts as |
2001 | address offsets within a string. Unfortunately this means that if |
2002 | the regular expression compiles to longer than 32767, it'll blow up. |
2003 | Usually when you want a regular expression this big, there is a better |
2004 | way to do it with multiple statements. See L<perlre>. |
2005 | |
2006 | =item Use of "$$<digit>" to mean "${$}<digit>" is deprecated |
2007 | |
2008 | (D) Perl versions before 5.004 misinterpreted any type marker followed |
2009 | by "$" and a digit. For example, "$$0" was incorrectly taken to mean |
2010 | "${$}0" instead of "${$0}". This bug is (mostly) fixed in Perl 5.004. |
2011 | |
2012 | However, the developers of Perl 5.004 could not fix this bug completely, |
2013 | because at least two widely-used modules depend on the old meaning of |
2014 | "$$0" in a string. So Perl 5.004 still interprets "$$<digit>" in the |
2015 | old (broken) way inside strings; but it generates this message as a |
2016 | warning. And in Perl 5.005, this special treatment will cease. |
2017 | |
2018 | =back |
3175b8cd |
2019 | |
ba8251e8 |
2020 | =head1 BUGS |
2021 | |
437784d6 |
2022 | If you find what you think is a bug, you might check the |
14218588 |
2023 | articles recently posted to the comp.lang.perl.misc newsgroup. |
ba8251e8 |
2024 | There may also be information at http://www.perl.com/perl/, the Perl |
2025 | Home Page. |
2026 | |
2027 | If you believe you have an unreported bug, please run the B<perlbug> |
14218588 |
2028 | program included with your release. Make sure to trim your bug down |
ba8251e8 |
2029 | to a tiny but sufficient test case. Your bug report, along with the |
14218588 |
2030 | output of C<perl -V>, will be sent off to perlbug@perl.com to be |
ba8251e8 |
2031 | analysed by the Perl porting team. |
2032 | |
2033 | =head1 SEE ALSO |
2034 | |
2035 | The F<Changes> file for exhaustive details on what changed. |
2036 | |
2037 | The F<INSTALL> file for how to build Perl. |
2038 | |
2039 | The F<README> file for general stuff. |
2040 | |
2041 | The F<Artistic> and F<Copying> files for copyright information. |
2042 | |
2043 | =head1 HISTORY |
2044 | |
a5222a85 |
2045 | Written by Gurusamy Sarathy <F<gsar@activestate.com>>, with many |
2046 | contributions from The Perl Porters. |
ba8251e8 |
2047 | |
2048 | Send omissions or corrections to <F<perlbug@perl.com>>. |
2049 | |
2050 | =cut |