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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_64) |
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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 old ones |
19 | that have been enhanced 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 | |
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29 | In addition to C<BEGIN>, C<INIT>, C<END>, C<DESTROY> and C<AUTOLOAD>, |
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30 | subroutines named C<STOP> are now special. These are queued up during |
31 | compilation and behave similar to END blocks, except they are called at |
32 | the end of compilation rather than at the end of execution. They cannot |
33 | be called directly. |
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34 | |
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35 | =item Treatment of list slices of undef has changed |
36 | |
37 | When taking a slice of a literal list (as opposed to a slice of |
38 | an array or hash), Perl used to return an empty list if the |
39 | result happened to be composed of all undef values. |
40 | |
41 | The new behavior is to produce an empty list if (and only if) |
42 | the original list was empty. Consider the following example: |
43 | |
44 | @a = (1,undef,undef,2)[2,1,2]; |
45 | |
46 | The old behavior would have resulted in @a having no elements. |
47 | The new behavior ensures it has three undefined elements. |
48 | |
49 | Note in particular that the behavior of slices of the following |
50 | cases remains unchanged: |
51 | |
52 | @a = ()[1,2]; |
53 | @a = (getpwent)[7,0]; |
54 | @a = (anything_returning_empty_list())[2,1,2]; |
55 | @a = @b[2,1,2]; |
56 | @a = @c{'a','b','c'}; |
57 | |
58 | See L<perldata>. |
59 | |
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60 | =item Possibly changed pseudo-random number generator |
61 | |
62 | In 5.005_0x and earlier, perl's rand() function used the C library |
63 | rand(3) function. As of 5.005_52, Configure tests for drand48(), |
64 | random(), and rand() (in that order) and picks the first one it finds. |
65 | Perl programs that depend on reproducing a specific set of pseudo-random |
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66 | numbers will now likely produce different output. You can use |
67 | C<sh Configure -Drandfunc=rand> to obtain the old behavior. |
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68 | |
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69 | =item Hashing function for hash keys has changed |
70 | |
71 | Perl hashes are not order preserving. The apparently random order |
72 | encountered when iterating on the contents of a hash is determined |
73 | by the hashing algorithm used. To improve the distribution of lower |
74 | bits in the hashed value, the algorithm has changed slightly as of |
75 | 5.005_52. When iterating over hashes, this may yield a random order |
76 | that is B<different> from that of previous versions. |
77 | |
78 | =item C<undef> fails on read only values |
79 | |
80 | Using the C<undef> operator on a readonly value (such as $1) has |
81 | the same effect as assigning C<undef> to the readonly value--it |
82 | throws an exception. |
83 | |
84 | =item Close-on-exec bit may be set on pipe() handles |
85 | |
86 | On systems that support a close-on-exec flag on filehandles, the |
87 | flag will be set for any handles created by pipe(), if that is |
88 | warranted by the value of $^F that may be in effect. Earlier |
89 | versions neglected to set the flag for handles created with |
90 | pipe(). See L<perlfunc/pipe> and L<perlvar/$^F>. |
91 | |
92 | =item Writing C<"$$1"> to mean C<"${$}1"> is unsupported |
93 | |
94 | Perl 5.004 deprecated the interpretation of C<$$1> and |
95 | similar within interpolated strings to mean C<$$ . "1">, |
96 | but still allowed it. |
97 | |
98 | In Perl 5.6 and later, C<"$$1"> always means C<"${$1}">. |
99 | |
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100 | =item delete(), values() and C<\(%h)> operate on aliases to values, not copies |
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101 | |
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102 | delete(), each(), values() and hashes in a list context return the actual |
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103 | values in the hash, instead of copies (as they used to in earlier |
104 | versions). Typical idioms for using these constructs copy the |
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105 | returned values, but this can make a significant difference when |
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106 | creating references to the returned values. |
107 | |
108 | Keys in the hash are still returned as copies when iterating on |
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109 | a hash. |
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110 | |
111 | =item vec(EXPR,OFFSET,BITS) enforces powers-of-two BITS |
112 | |
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113 | vec() generates a run-time error if the BITS argument is not |
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114 | a valid power-of-two integer. |
115 | |
116 | =item Text of some diagnostic output has changed |
117 | |
118 | Most references to internal Perl operations in diagnostics |
119 | have been changed to be more descriptive. This may be an |
120 | issue for programs that may incorrectly rely on the exact |
121 | text of diagnostics for proper functioning. |
122 | |
123 | =item C<%@> has been removed |
124 | |
125 | The undocumented special variable C<%@> that used to accumulate |
126 | "background" errors (such as those that happen in DESTROY()) |
127 | has been removed, because it could potentially result in memory |
128 | leaks. |
129 | |
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130 | =item Parenthesized not() behaves like a list operator |
131 | |
132 | The C<not> operator now falls under the "if it looks like a function, |
133 | it behaves like a function" rule. |
134 | |
135 | As a result, the parenthesized form can be used with C<grep> and C<map>. |
136 | The following construct used to be a syntax error before, but it works |
137 | as expected now: |
138 | |
139 | grep not($_), @things; |
140 | |
141 | On the other hand, using C<not> with a literal list slice may not |
142 | work. The following previously allowed construct: |
143 | |
144 | print not (1,2,3)[0]; |
145 | |
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146 | needs to be written with additional parentheses now: |
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147 | |
148 | print not((1,2,3)[0]); |
149 | |
150 | The behavior remains unaffected when C<not> is not followed by parentheses. |
151 | |
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152 | =back |
153 | |
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154 | =head2 C Source Incompatibilities |
155 | |
156 | =over 4 |
157 | |
158 | =item C<PERL_POLLUTE> |
159 | |
160 | Release 5.005 grandfathered old global symbol names by providing preprocessor |
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161 | macros for extension source compatibility. As of release 5.6, these |
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162 | preprocessor definitions are not available by default. You need to explicitly |
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163 | compile perl with C<-DPERL_POLLUTE> to get these definitions. For |
164 | extensions still using the old symbols, this option can be |
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165 | specified via MakeMaker: |
166 | |
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167 | perl Makefile.PL POLLUTE=1 |
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168 | |
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169 | =item C<PERL_IMPLICIT_CONTEXT> |
170 | |
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171 | PERL_IMPLICIT_CONTEXT is automatically enabled whenever Perl is built |
172 | with one of -Dusethreads, -Dusemultiplicity, or both. It is not |
173 | intended to be enabled by users at this time. |
174 | |
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175 | This new build option provides a set of macros for all API functions |
176 | such that an implicit interpreter/thread context argument is passed to |
177 | every API function. As a result of this, something like C<sv_setsv(foo,bar)> |
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178 | amounts to a macro invocation that actually translates to something like |
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179 | C<Perl_sv_setsv(my_perl,foo,bar)>. While this is generally expected |
180 | to not have any significant source compatibility issues, the difference |
181 | between a macro and a real function call will need to be considered. |
182 | |
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183 | This means that there B<is> a source compatibility issue as a result of |
184 | this if your extensions attempt to use pointers to any of the Perl API |
185 | functions. |
186 | |
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187 | Note that the above issue is not relevant to the default build of |
188 | Perl, whose interfaces continue to match those of prior versions |
189 | (but subject to the other options described here). |
190 | |
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191 | See L<perlguts/"The Perl API"> for detailed information on the |
192 | ramifications of building Perl using this option. |
193 | |
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194 | =item C<PERL_POLLUTE_MALLOC> |
195 | |
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196 | Enabling Perl's malloc in release 5.005 and earlier caused |
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197 | the namespace of system versions of the malloc family of functions to |
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198 | be usurped by the Perl versions, since by default they used the |
199 | same names. |
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200 | |
201 | Besides causing problems on platforms that do not allow these functions to |
202 | be cleanly replaced, this also meant that the system versions could not |
203 | be called in programs that used Perl's malloc. Previous versions of Perl |
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204 | have allowed this behaviour to be suppressed with the HIDEMYMALLOC and |
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205 | EMBEDMYMALLOC preprocessor definitions. |
206 | |
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207 | As of release 5.6, Perl's malloc family of functions have default names |
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208 | distinct from the system versions. You need to explicitly compile perl with |
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209 | C<-DPERL_POLLUTE_MALLOC> to get the older behaviour. HIDEMYMALLOC |
210 | and EMBEDMYMALLOC have no effect, since the behaviour they enabled is now |
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211 | the default. |
212 | |
213 | Note that these functions do B<not> constitute Perl's memory allocation API. |
214 | See L<perlguts/"Memory Allocation"> for further information about that. |
215 | |
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216 | =back |
217 | |
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218 | =head2 Compatible C Source API Changes |
219 | |
220 | =over |
221 | |
222 | =item C<PATCHLEVEL> is now C<PERL_VERSION> |
223 | |
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224 | The cpp macros C<PERL_REVISION>, C<PERL_VERSION>, and C<PERL_SUBVERSION> |
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225 | are now available by default from perl.h, and reflect the base revision, |
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226 | patchlevel, and subversion respectively. C<PERL_REVISION> had no |
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227 | prior equivalent, while C<PERL_VERSION> and C<PERL_SUBVERSION> were |
228 | previously available as C<PATCHLEVEL> and C<SUBVERSION>. |
229 | |
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230 | The new names cause less pollution of the B<cpp> namespace and reflect what |
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231 | the numbers have come to stand for in common practice. For compatibility, |
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232 | the old names are still supported when F<patchlevel.h> is explicitly |
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233 | included (as required before), so there is no source incompatibility |
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234 | from the change. |
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235 | |
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236 | =item Support for C++ exceptions |
237 | |
238 | change#3386, also needs perlguts documentation |
239 | [TODO - Chip Salzenberg <chip@perlsupport.com>] |
240 | |
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241 | =back |
242 | |
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243 | =head2 Binary Incompatibilities |
244 | |
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245 | The default build of this release is binary compatible with the 5.005 |
246 | release or its maintenance versions. |
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247 | |
248 | The usethreads or usemultiplicity builds are B<not> binary compatible |
249 | with the corresponding builds in 5.005. |
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250 | |
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251 | =head1 Installation and Configuration Improvements |
252 | |
253 | =head2 New Configure flags |
254 | |
255 | The following new flags may be enabled on the Configure command line |
256 | by running Configure with C<-Dflag>. |
257 | |
258 | usemultiplicity |
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259 | |
260 | uselongdouble |
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261 | usemorebits |
262 | uselargefiles |
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263 | |
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264 | =head2 -Dusethreads and -Duse64bits now more daring |
265 | |
266 | The Configure options enabling the use of threads and the use of |
267 | 64-bitness are now more daring in the sense that they no more have |
268 | an explicit list of operating systems of known threads/64-bit |
269 | capabilities. In other words: if your operating system has the |
270 | necessary APIs, you should be able just to go ahead and use them. |
271 | See also L<"64-bit support">. |
272 | |
273 | =head2 Long Doubles |
274 | |
275 | Some platforms have "long doubles", floating point numbers of even |
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276 | larger range than ordinary "doubles". To enable using long doubles for |
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277 | Perl's scalars, use -Duselongdouble. |
278 | |
279 | =head2 -Dusemorebits |
280 | |
281 | You can enable both -Duse64bits and -Dlongdouble by -Dusemorebits. |
282 | See also L<"64-bit support">. |
283 | |
284 | =head2 -Duselargefiles |
285 | |
286 | Some platforms support large files, files larger than two gigabytes. |
287 | See L<"Large file support"> for more information. |
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288 | |
289 | =head2 installusrbinperl |
290 | |
291 | You can use "Configure -Uinstallusrbinperl" which causes installperl |
292 | to skip installing perl also as /usr/bin/perl. This is useful if you |
293 | prefer not to modify /usr/bin for some reason or another but harmful |
294 | because many scripts assume to find Perl in /usr/bin/perl. |
295 | |
296 | =head2 SOCKS support |
297 | |
298 | You can use "Configure -Dusesocks" which causes Perl to probe |
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299 | for the SOCKS (v5, not v4) proxy protocol library, |
300 | http://www.socks.nec.com/ |
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301 | |
302 | =head2 C<-A> flag |
303 | |
304 | You can "post-edit" the Configure variables using the Configure C<-A> |
305 | flag. The editing happens immediately after the platform specific |
306 | hints files have been processed but before the actual configuration |
307 | process starts. Run C<Configure -h> to find out the full C<-A> syntax. |
308 | |
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309 | =head2 Enhanced Installation Directories |
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310 | |
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311 | The installation structure has been enriched to improve the support for |
312 | maintaining multiple versions of perl, to provide locations for |
313 | vendor-supplied modules and scripts, and to ease maintenance of |
314 | locally-added modules and scripts. See the section on Installation |
315 | Directories in the INSTALL file for complete details. For most users |
316 | building and installing from source, the defaults should be fine. |
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317 | |
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318 | =head1 Core Changes |
319 | |
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320 | =head2 Unicode and UTF-8 support |
321 | |
322 | Perl can optionally use UTF-8 as its internal representation for character |
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323 | strings. The C<utf8> pragma enables this support in the current lexical |
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324 | scope. See L<utf8> for more information. |
325 | |
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326 | =head2 Interpreter threads |
327 | |
328 | WARNING: This is an experimental feature in a pre-alpha state. Use |
329 | at your own risk. |
330 | |
331 | Perl 5.005_63 introduces the beginnings of support for running multiple |
332 | interpreters concurrently in different threads. In conjunction with |
333 | the perl_clone() API call, which can be used to selectively duplicate |
334 | the state of any given interpreter, it is possible to compile a |
335 | piece of code once in an interpreter, clone that interpreter |
336 | one or more times, and run all the resulting interpreters in distinct |
337 | threads. |
338 | |
339 | On Windows, this feature is used to emulate fork() at the interpreter |
340 | level. See L<perlfork>. |
341 | |
342 | This feature is still in evolution. It is eventually meant to be used |
343 | to selectively clone a subroutine and data reachable from that |
344 | subroutine in a separate interpreter and run the cloned subroutine |
345 | in a separate thread. Since there is no shared data between the |
346 | interpreters, little or no locking will be needed (unless parts of |
347 | the symbol table are explicitly shared). This is obviously intended |
348 | to be an easy-to-use replacement for the existing threads support. |
349 | |
350 | Support for cloning interpreters must currently be manually enabled |
351 | by defining the cpp macro USE_ITHREADS on non-Windows platforms. |
352 | (See win32/Makefile for how to enable it on Windows.) The resulting |
353 | perl executable will be functionally identical to one that was built |
354 | without USE_ITHREADS, but the perl_clone() API call will only be |
355 | available in the former. |
356 | |
357 | USE_ITHREADS enables Perl source code changes that provide a clear |
358 | separation between the op tree and the data it operates with. The |
359 | former is considered immutable, and can therefore be shared between |
360 | an interpreter and all of its clones, while the latter is considered |
361 | local to each interpreter, and is therefore copied for each clone. |
362 | |
363 | Note that building Perl with the -Dusemultiplicity Configure option |
364 | is adequate if you wish to run multiple B<independent> interpreters |
365 | concurrently in different threads. USE_ITHREADS only needs to be |
366 | enabled if you wish to obtain access to perl_clone() and cloned |
367 | interpreters. |
368 | |
369 | [XXX TODO - the Compiler backends may be broken when USE_ITHREADS is |
370 | enabled.] |
371 | |
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372 | =head2 Lexically scoped warning categories |
373 | |
374 | You can now control the granularity of warnings emitted by perl at a finer |
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375 | level using the C<use warnings> pragma. See L<warnings> and L<perllexwarn> |
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376 | for details. |
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377 | |
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378 | =head2 Lvalue subroutines |
379 | |
380 | WARNING: This is an experimental feature. |
381 | |
382 | change#4081 |
383 | [TODO - Ilya Zakharevich <ilya@math.ohio-state.edu>, |
384 | Tuomas Lukka <lukka@fas.harvard.edu>)] |
385 | |
386 | =head2 "our" declarations |
387 | |
388 | An "our" declaration introduces a value that can be best understood |
389 | as a lexically scoped symbolic alias to a global variable in the |
390 | current package. This is mostly useful as an alternative to the |
391 | C<vars> pragma, but also provides the opportunity to introduce |
392 | typing and other attributes for such variables. See L<perlfunc/our>. |
393 | |
394 | =head2 Weak references |
395 | |
396 | WARNING: This is an experimental feature. |
397 | |
398 | change#3385, also need perlguts documentation |
399 | |
400 | [TODO - Tuomas Lukka <lukka@fas.harvard.edu>] |
401 | |
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402 | =head2 File globbing implemented internally |
403 | |
404 | WARNING: This is currently an experimental feature. Interfaces and |
405 | implementation are likely to change. |
406 | |
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407 | Perl now uses the File::Glob implementation of the glob() operator |
408 | automatically. This avoids using an external csh process and the |
409 | problems associated with it. |
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410 | |
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411 | =head2 Binary numbers supported |
412 | |
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413 | Binary numbers are now supported as literals, in s?printf formats, and |
414 | C<oct()>: |
415 | |
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416 | $answer = 0b101010; |
417 | printf "The answer is: %b\n", oct("0b101010"); |
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418 | |
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419 | =head2 Some arrows may be omitted in calls through references |
420 | |
421 | Perl now allows the arrow to be omitted in many constructs |
422 | involving subroutine calls through references. For example, |
423 | C<$foo[10]->('foo')> may now be written C<$foo[10]('foo')>. |
424 | This is rather similar to how the arrow may be omitted from |
425 | C<$foo[10]->{'foo'}>. Note however, that the arrow is still |
426 | required for C<foo(10)->('bar')>. |
427 | |
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428 | =head2 syswrite() ease-of-use |
429 | |
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430 | The length argument of C<syswrite()> has become optional. |
431 | |
432 | =head2 Filehandles can be autovivified |
433 | |
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434 | Similar to how constructs such as C<$x->[0]> autovivify a reference, |
435 | open() now autovivifies a filehandle if the first argument is an |
436 | uninitialized variable. This allows the constructs C<open(my $fh, ...)> and |
437 | C<open(local $fh,...)> to be used to create filehandles that will |
438 | conveniently be closed automatically when the scope ends, provided there |
439 | are no other references to them. This largely eliminates the need for |
440 | typeglobs when opening filehandles that must be passed around, as in the |
441 | following example: |
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442 | |
443 | sub myopen { |
444 | open my $fh, "@_" |
445 | or die "Can't open '@_': $!"; |
446 | return $fh; |
447 | } |
448 | |
449 | { |
450 | my $f = myopen("</etc/motd"); |
451 | print <$f>; |
452 | # $f implicitly closed here |
453 | } |
454 | |
455 | [TODO - this idiom needs more pod penetration] |
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456 | |
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457 | =head2 64-bit support |
458 | |
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459 | All platforms that have 64-bit integers either (a) natively as longs |
460 | or ints (b) via special compiler flags (c) using long long are able to |
461 | use "quads" (64-integers) as follows: |
462 | |
463 | =over 4 |
464 | |
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465 | =item * |
466 | |
467 | constants (decimal, hexadecimal, octal, binary) in the code |
468 | |
469 | =item * |
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470 | |
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471 | arguments to oct() and hex() |
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472 | |
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473 | =item * |
474 | |
475 | arguments to print(), printf() and sprintf() (flag prefixes ll, L, q) |
476 | |
477 | =item * |
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478 | |
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479 | printed as such |
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480 | |
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481 | =item * |
482 | |
483 | pack() and unpack() "q" and "Q" formats |
484 | |
485 | =item * |
486 | |
487 | in basic arithmetics: + - * / % |
488 | |
489 | =item * |
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490 | |
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491 | vec() (but see the below note about bit arithmetics) |
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492 | |
493 | =back |
494 | |
495 | Note that unless you have the case (a) you will have to configure |
496 | and compile Perl using the -Duse64bits Configure flag. |
497 | |
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498 | Unfortunately bit arithmetics (&, |, ^, ~, <<, >>) for numbers are not |
499 | 64-bit clean, they are explictly forced to be 32-bit. Bit arithmetics |
500 | for bit vectors (created by vec()) are not limited in their width. |
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501 | |
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502 | Last but not least: note that due to Perl's habit of always using |
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503 | floating point numbers the quads are still not true integers. |
504 | When quads overflow their limits (0...18_446_744_073_709_551_615 unsigned, |
505 | -9_223_372_036_854_775_808...9_223_372_036_854_775_807 signed), they |
506 | are silently promoted to floating point numbers, after which they will |
507 | start losing precision (their lower digits). |
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508 | |
509 | =head2 Large file support |
510 | |
511 | If you have filesystems that support "large files" (files larger than |
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512 | 2 gigabytes), you may now also be able to create and access them from |
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513 | Perl. You have to use Configure -Duselargefiles. Turning on the |
514 | large file support turns on also the 64-bit support, for obvious reasons. |
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515 | |
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516 | Note that in addition to requiring a proper file system to do large |
517 | files you may also need to adjust your per-process (or your |
518 | per-system, or per-process-group, or per-user-group) maximum filesize |
519 | limits before running Perl scripts that try to handle large files, |
520 | especially if you intend to write such files. |
521 | |
522 | Finally, in addition to your process/process group maximum filesize |
523 | limits, you may have quota limits on your filesystems that stop you |
524 | (your user id or your user group id) from using large files. |
525 | |
526 | Adjusting your process/user/group/file system/operating system limits |
527 | is outside the scope of Perl core language. For process limits, you |
528 | may try increasing the limits using your shell's limits/limit/ulimit |
529 | command before running Perl. The BSD::Resource extension (not |
530 | included with the standard Perl distribution) may also be of use, it |
531 | offers the getrlimit/setrlimit interface that can be used to adjust |
532 | process resource usage limits, including the maximum filesize limit. |
475d79b5 |
533 | |
aa855319 |
534 | =head2 Long doubles |
535 | |
536 | In some systems you may be able to use long doubles to enhance the |
537 | range of precision of your double precision floating point numbers |
538 | (that is, Perl's numbers). Use Configure -Duselongdouble to enable |
539 | this support (if it is available). |
540 | |
541 | =head2 "more bits" |
542 | |
543 | You can Configure -Dusemorebits to turn on both the 64-bit support |
544 | and the long double support. |
09bef843 |
545 | |
43481408 |
546 | =head2 Enhanced support for sort() subroutines |
547 | |
548 | Perl subroutines with a prototype of C<($$)> and XSUBs in general can |
549 | now be used as sort subroutines. In either case, the two elements to |
af365420 |
550 | be compared are passed as normal parameters in @_. See L<perlfunc/sort>. |
43481408 |
551 | |
552 | For unprototyped sort subroutines, the historical behavior of passing |
553 | the elements to be compared as the global variables $a and $b remains |
554 | unchanged. |
555 | |
62c18ce2 |
556 | =head2 Better syntax checks on parenthesized unary operators |
557 | |
558 | Expressions such as: |
559 | |
14218588 |
560 | print defined(&foo,&bar,&baz); |
561 | print uc("foo","bar","baz"); |
562 | undef($foo,&bar); |
62c18ce2 |
563 | |
7711098a |
564 | used to be accidentally allowed in earlier versions, and produced |
14218588 |
565 | unpredictable behaviour. Some produced ancillary warnings |
566 | when used in this way; others silently did the wrong thing. |
62c18ce2 |
567 | |
568 | The parenthesized forms of most unary operators that expect a single |
14218588 |
569 | argument now ensure that they are not called with more than one |
570 | argument, making the cases shown above syntax errors. The usual |
571 | behaviour of: |
62c18ce2 |
572 | |
14218588 |
573 | print defined &foo, &bar, &baz; |
574 | print uc "foo", "bar", "baz"; |
575 | undef $foo, &bar; |
62c18ce2 |
576 | |
577 | remains unchanged. See L<perlop>. |
578 | |
3e3318e7 |
579 | =head2 POSIX character class syntax [: :] supported |
580 | |
581 | For example to match alphabetic characters use /[[:alpha:]]/. |
582 | See L<perlre> for details. |
583 | |
5a929a98 |
584 | =head2 Improved C<qw//> operator |
8127e0e3 |
585 | |
26ef7447 |
586 | The C<qw//> operator is now evaluated at compile time into a true list |
587 | instead of being replaced with a run time call to C<split()>. This |
14218588 |
588 | removes the confusing misbehaviour of C<qw//> in scalar context, which |
589 | had inherited that behaviour from split(). |
26ef7447 |
590 | |
591 | Thus: |
592 | |
593 | $foo = ($bar) = qw(a b c); print "$foo|$bar\n"; |
594 | |
595 | now correctly prints "3|a", instead of "2|a". |
8127e0e3 |
596 | |
5a929a98 |
597 | =head2 pack() format 'Z' supported |
598 | |
599 | The new format type 'Z' is useful for packing and unpacking null-terminated |
600 | strings. See L<perlfunc/"pack">. |
601 | |
4d0c1c44 |
602 | =head2 pack() format modifier '!' supported |
ee3907e2 |
603 | |
14218588 |
604 | The new format type modifier '!' is useful for packing and unpacking |
ee3907e2 |
605 | native shorts, ints, and longs. See L<perlfunc/"pack">. |
606 | |
f29c64d6 |
607 | =head2 pack() and unpack() support counted strings |
608 | |
a5222a85 |
609 | The template character '/' can be used to specify a counted string |
f29c64d6 |
610 | type to be packed or unpacked. See L<perlfunc/"pack">. |
611 | |
a5222a85 |
612 | =head2 Comments in pack() templates |
613 | |
614 | The '#' character in a template introduces a comment up to |
615 | end of the line. This facilitates documentation of pack() |
616 | templates. |
617 | |
2b92dfce |
618 | =head2 $^X variables may now have names longer than one character |
619 | |
620 | Formerly, $^X was synonymous with ${"\cX"}, but $^XY was a syntax |
621 | error. Now variable names that begin with a control character may be |
622 | arbitrarily long. However, for compatibility reasons, these variables |
623 | I<must> be written with explicit braces, as C<${^XY}> for example. |
14218588 |
624 | C<${^XYZ}> is synonymous with ${"\cXYZ"}. Variable names with more |
2b92dfce |
625 | than one control character, such as C<${^XY^Z}>, are illegal. |
626 | |
14218588 |
627 | The old syntax has not changed. As before, `^X' may be either a |
628 | literal control-X character or the two-character sequence `caret' plus |
629 | `X'. When braces are omitted, the variable name stops after the |
2b92dfce |
630 | control character. Thus C<"$^XYZ"> continues to be synonymous with |
7711098a |
631 | C<$^X . "YZ"> as before. |
2b92dfce |
632 | |
633 | As before, lexical variables may not have names beginning with control |
634 | characters. As before, variables whose names begin with a control |
14218588 |
635 | character are always forced to be in package `main'. All such variables |
636 | are reserved for future extensions, except those that begin with |
09bef843 |
637 | C<^_>, which may be used by user programs and are guaranteed not to |
14218588 |
638 | acquire special meaning in any future version of Perl. |
2b92dfce |
639 | |
09bef843 |
640 | =head2 C<use attrs> implicit in subroutine attributes |
641 | |
642 | Formerly, if you wanted to mark a subroutine as being a method call or |
643 | as requiring an automatic lock() when it is entered, you had to declare |
644 | that with a C<use attrs> pragma in the body of the subroutine. |
645 | That can now be accomplished with a declaration syntax, like this: |
646 | |
647 | sub mymethod : locked, method ; |
648 | ... |
649 | sub mymethod : locked, method { |
650 | ... |
651 | } |
652 | |
653 | F<AutoSplit.pm> and F<SelfLoader.pm> have been updated to keep the attributes |
654 | with the stubs they provide. See L<attributes>. |
655 | |
a5222a85 |
656 | =head2 Regular expression improvements |
657 | |
658 | change#2827,2373,2372,2365,1813,1800,4112,4158,4215,4301 |
659 | [TODO - Ilya Zakharevich <ilya@math.ohio-state.edu>] |
660 | |
661 | =head2 Overloading improvements |
662 | |
663 | change#2150 |
664 | [TODO - Ilya Zakharevich <ilya@math.ohio-state.edu>] |
665 | |
666 | =head2 open() with more than two arguments |
667 | |
668 | [TODO - Ilya Zakharevich <ilya@math.ohio-state.edu>] |
669 | |
670 | =head2 Support for interpolating named characters |
671 | |
672 | change#4052 |
673 | [TODO - Ilya Zakharevich <ilya@math.ohio-state.edu>] |
674 | |
08cd8952 |
675 | =head2 Experimental support for user-hooks in @INC |
a5222a85 |
676 | |
677 | [TODO - Ken Fox <kfox@ford.com>] |
678 | |
679 | =head2 C<require> and C<do> may be overridden |
680 | |
681 | C<require> and C<do 'file'> operations may be overridden locally |
682 | by importing subroutines of the same name into the current package |
683 | (or globally by importing them into the CORE::GLOBAL:: namespace). |
684 | Overriding C<require> will also affect C<use>, provided the override |
685 | is visible at compile-time. |
686 | See L<perlsub/"Overriding Built-in Functions">. |
687 | |
688 | =head2 New variable $^C reflects C<-c> switch |
689 | |
08cd8952 |
690 | C<$^C> has a boolean value that reflects whether perl is being run |
a5222a85 |
691 | in compile-only mode (i.e. via the C<-c> switch). Since |
692 | BEGIN blocks are executed under such conditions, this variable |
693 | enables perl code to determine whether actions that make sense |
694 | only during normal running are warranted. See L<perlvar>. |
695 | |
696 | =head2 Optional Y2K warnings |
697 | |
698 | If Perl is built with the cpp macro C<PERL_Y2KWARN> defined, |
699 | it emits optional warnings when concatenating the number 19 |
700 | with another number. |
701 | |
702 | This behavior must be specifically enabled when running Configure. |
703 | See L<INSTALL> and L<README.Y2K>. |
704 | |
fbad3eb5 |
705 | =head1 Significant bug fixes |
706 | |
707 | =head2 E<lt>HANDLEE<gt> on empty files |
708 | |
709 | With C<$/> set to C<undef>, slurping an empty file returns a string of |
14218588 |
710 | zero length (instead of C<undef>, as it used to) the first time the |
711 | HANDLE is read. Further reads yield C<undef>. |
fbad3eb5 |
712 | |
713 | This means that the following will append "foo" to an empty file (it used |
14218588 |
714 | to do nothing): |
fbad3eb5 |
715 | |
716 | perl -0777 -pi -e 's/^/foo/' empty_file |
717 | |
14218588 |
718 | The behaviour of: |
fbad3eb5 |
719 | |
720 | perl -pi -e 's/^/foo/' empty_file |
721 | |
722 | is unchanged (it continues to leave the file empty). |
723 | |
0244c3a4 |
724 | =head2 C<eval '...'> improvements |
725 | |
726 | Line numbers (as reflected by caller() and most diagnostics) within |
727 | C<eval '...'> were often incorrect when here documents were involved. |
728 | This has been corrected. |
729 | |
730 | Lexical lookups for variables appearing in C<eval '...'> within |
731 | functions that were themselves called within an C<eval '...'> were |
14218588 |
732 | searching the wrong place for lexicals. The lexical search now |
733 | correctly ends at the subroutine's block boundary. |
0244c3a4 |
734 | |
735 | Parsing of here documents used to be flawed when they appeared as |
736 | the replacement expression in C<eval 's/.../.../e'>. This has |
737 | been fixed. |
738 | |
a5222a85 |
739 | =head2 All compilation errors are true errors |
740 | |
741 | Some "errors" encountered at compile time were by neccessity |
742 | generated as warnings followed by eventual termination of the |
743 | program. This enabled more such errors to be reported in a |
744 | single run, rather than causing a hard stop at the first error |
745 | that was encountered. |
746 | |
747 | The mechanism for reporting such errors has been reimplemented |
748 | to queue compile-time errors and report them at the end of the |
749 | compilation as true errors rather than as warnings. This fixes |
08cd8952 |
750 | cases where error messages leaked through in the form of warnings |
751 | when code was compiled at run time using C<eval STRING>, and |
752 | also allows such errors to be reliably trapped using __DIE__ hooks. |
a5222a85 |
753 | |
45bc9206 |
754 | =head2 Automatic flushing of output buffers |
755 | |
14218588 |
756 | fork(), exec(), system(), qx//, and pipe open()s now flush buffers |
757 | of all files opened for output when the operation |
758 | was attempted. This mostly eliminates confusing |
45bc9206 |
759 | buffering mishaps suffered by users unaware of how Perl internally |
14218588 |
760 | handles I/O. |
45bc9206 |
761 | |
af8c498a |
762 | =head2 Better diagnostics on meaningless filehandle operations |
763 | |
764 | Constructs such as C<open(E<lt>FHE<gt>)> and C<close(E<lt>FHE<gt>)> |
765 | are compile time errors. Attempting to read from filehandles that |
766 | were opened only for writing will now produce warnings (just as |
767 | writing to read-only filehandles does). |
768 | |
a5222a85 |
769 | =head2 Where possible, buffered data discarded from duped input filehandle |
770 | |
771 | C<open(NEW, "E<lt>&OLD")> now attempts to discard any data that |
772 | was previously read and buffered in C<OLD> before duping the handle. |
773 | On platforms where doing this is allowed, the next read operation |
774 | on C<NEW> will return the same data as the corresponding operation |
775 | on C<OLD>. Formerly, it would have returned the data from the start |
776 | of the following disk block instead. |
777 | |
778 | =head2 system(), backticks and pipe open now reflect exec() failure |
779 | |
780 | On Unix and similar platforms, system(), qx() and open(FOO, "cmd |") |
781 | etc., are implemented via fork() and exec(). When the underlying |
782 | exec() fails, earlier versions did not report the error properly, |
783 | since the exec() happened to be in a different process. |
784 | |
785 | The child process now communicates with the parent about the |
437784d6 |
786 | error in launching the external command, which allows these |
a5222a85 |
787 | constructs to return with their usual error value and set $!. |
788 | |
789 | =head2 Implicitly closed filehandles are safer |
790 | |
791 | Sometimes implicitly closed filehandles (as when they are localized, |
792 | and Perl automatically closes them on exiting the scope) could |
793 | inadvertently set $? or $!. This has been corrected. |
794 | |
795 | =head2 C<(\$)> prototype and C<$foo{a}> |
796 | |
797 | An scalar reference prototype now correctly allows a hash or |
798 | array element in that slot. |
799 | |
800 | =head2 Pseudo-hashes work better |
801 | |
802 | Dereferencing some types of reference values in a pseudo-hash, |
803 | such as C<$ph->{foo}[1]>, was accidentally disallowed. This has |
804 | been corrected. |
805 | |
806 | When applied to a pseudo-hash element, exists() now reports whether |
807 | the specified value exists, not merely if the key is valid. |
808 | |
809 | =head2 C<goto &sub> and AUTOLOAD |
810 | |
08cd8952 |
811 | The C<goto &sub> construct works correctly when C<&sub> happens |
a5222a85 |
812 | to be autoloaded. |
813 | |
814 | =head2 C<-bareword> allowed under C<use integer> |
815 | |
816 | The autoquoting of barewords preceded by C<-> did not work |
817 | in prior versions when the C<integer> pragma was enabled. |
818 | This has been fixed. |
819 | |
820 | =head2 Boolean assignment operators are legal lvalues |
821 | |
822 | Constructs such as C<($a ||= 2) += 1> are now allowed. |
823 | |
824 | =head2 C<sort $coderef @foo> allowed |
825 | |
826 | sort() did not accept a subroutine reference as the comparison |
08cd8952 |
827 | function in earlier versions. This is now permitted. |
a5222a85 |
828 | |
829 | =head2 Failures in DESTROY() |
830 | |
831 | When code in a destructor threw an exception, it went unnoticed |
832 | in earlier versions of Perl, unless someone happened to be |
833 | looking in $@ just after the point the destructor happened to |
834 | run. Such failures are now visible as warnings when warnings are |
835 | enabled. |
836 | |
837 | =head2 Locale bugs fixed |
54195c32 |
838 | |
437784d6 |
839 | printf() and sprintf() previously reset the numeric locale |
67d3893f |
840 | back to the default "C" locale. This has been fixed. |
841 | |
842 | Numbers formatted according to the local numeric locale |
843 | (such as using a decimal comma instead of a decimal dot) caused |
844 | "isn't numeric" warnings, even while the operations accessing |
845 | those numbers produced correct results. The warnings are gone. |
54195c32 |
846 | |
a5222a85 |
847 | =head2 Memory leaks |
848 | |
849 | The C<eval 'return sub {...}'> construct could sometimes leak |
850 | memory. This has been fixed. |
851 | |
852 | Operations that aren't filehandle constructors used to leak memory |
853 | when used on invalid filehandles. This has been fixed. |
854 | |
855 | Constructs that modified C<@_> could fail to deallocate values |
856 | in C<@_> and thus leak memory. This has been corrected. |
857 | |
858 | =head2 Spurious subroutine stubs after failed subroutine calls |
859 | |
860 | Perl could sometimes create empty subroutine stubs when a |
861 | subroutine was not found in the package. Such cases stopped |
862 | later method lookups from progressing into base packages. |
863 | This has been corrected. |
864 | |
865 | =head2 Consistent numeric conversions |
866 | |
867 | change#3378,3318 |
868 | [TODO - Ilya Zakharevich <ilya@math.ohio-state.edu>] |
869 | |
870 | =head2 Taint failures under C<-U> |
871 | |
872 | When running in unsafe mode, taint violations could sometimes |
873 | cause silent failures. This has been fixed. |
874 | |
875 | =head2 END blocks and the C<-c> switch |
876 | |
877 | Prior versions used to run BEGIN B<and> END blocks when Perl was |
878 | run in compile-only mode. Since this is typically not the expected |
08cd8952 |
879 | behavior, END blocks are not executed anymore when the C<-c> switch |
a5222a85 |
880 | is used. |
881 | |
4f25aa18 |
882 | See L<STOP blocks> for how to run things when the compile phase ends. |
a5222a85 |
883 | |
884 | =head2 Potential to leak DATA filehandles |
885 | |
886 | Using the C<__DATA__> token creates an implicit filehandle to |
887 | the file that contains the token. It is the program's |
888 | responsibility to close it when it is done reading from it. |
889 | |
890 | This caveat is now better explained in the documentation. |
891 | See L<perldata>. |
892 | |
893 | =head2 Diagnostics follow STDERR |
894 | |
895 | Diagnostic output now goes to whichever file the C<STDERR> handle |
896 | is pointing at, instead of always going to the underlying C runtime |
897 | library's C<stderr>. |
898 | |
899 | =head2 Other fixes for better diagnostics |
900 | |
437784d6 |
901 | Line numbers are no longer suppressed (under most likely circumstances) |
a5222a85 |
902 | during the global destruction phase. |
903 | |
904 | Diagnostics emitted from code running in threads other than the main |
905 | thread are now accompanied by the thread ID. |
906 | |
907 | Embedded null characters in diagnostics now actually show up. They |
908 | used to truncate the message in prior versions. |
909 | |
910 | $foo::a and $foo::b are now exempt from "possible typo" warnings only |
911 | if sort() is encountered in package foo. |
912 | |
501fbaef |
913 | Unrecognized alphabetic escapes encountered when parsing quote |
a5222a85 |
914 | constructs now generate a warning, since they may take on new |
915 | semantics in later versions of Perl. |
916 | |
917 | =head1 Performance enhancements |
918 | |
919 | =head2 Simple sort() using { $a <=> $b } and the like are optimized |
920 | |
08cd8952 |
921 | Many common sort() operations using a simple inlined block are now |
a5222a85 |
922 | optimized for faster performance. |
923 | |
924 | =head2 Optimized assignments to lexical variables |
925 | |
926 | Certain operations in the RHS of assignment statements have been |
927 | optimized to directly set the lexical variable on the LHS, |
928 | eliminating redundant copying overheads. |
929 | |
930 | =head2 Method lookups optimized |
931 | |
932 | [TODO - Chip Salzenberg <chip@perlsupport.com>] |
933 | |
934 | =head2 Faster mechanism to invoke XSUBs |
935 | |
936 | change#4044,4125 |
937 | [TODO - Ilya Zakharevich <ilya@math.ohio-state.edu>] |
938 | |
939 | =head2 Perl_malloc() improvements |
940 | |
941 | change#4237 |
942 | [TODO - Ilya Zakharevich <ilya@math.ohio-state.edu>] |
943 | |
944 | =head2 Faster subroutine calls |
945 | |
946 | Minor changes in how subroutine calls are handled internally |
947 | provide marginal improvements in performance. |
948 | |
949 | =head1 Platform specific changes |
950 | |
951 | =head2 Additional supported platforms |
ba8251e8 |
952 | |
5fdc711f |
953 | =over 4 |
954 | |
955 | =item * |
956 | |
6c67e1bb |
957 | VM/ESA is now supported. |
958 | |
5fdc711f |
959 | =item * |
960 | |
ee3907e2 |
961 | Siemens BS2000 is now supported under the POSIX Shell. |
962 | |
963 | =item * |
964 | |
2bb14304 |
965 | The Mach CThreads (NEXTSTEP, OPENSTEP) are now supported by the Thread |
966 | extension. |
6c67e1bb |
967 | |
5fdc711f |
968 | =item * |
969 | |
ee3907e2 |
970 | GNU/Hurd is now supported. |
6c67e1bb |
971 | |
00ad96e1 |
972 | =item * |
973 | |
974 | Rhapsody is now supported. |
975 | |
27806c82 |
976 | =item * |
977 | |
978 | EPOC is is now supported (on Psion 5). |
979 | |
5fdc711f |
980 | =back |
981 | |
a5222a85 |
982 | =head2 DOS |
983 | |
d524f05e |
984 | =over 4 |
985 | |
986 | =item * |
987 | |
988 | Perl now works with djgpp 2.02 (and 2.03 alpha). |
989 | |
990 | =item * |
991 | |
992 | Environment variable names are not converted to uppercase any more. |
993 | |
994 | =item * |
995 | |
996 | Wrong exit code from backticks now fixed. |
997 | |
998 | =item * |
999 | |
1000 | This port is still using its own builtin globbing. |
1001 | |
1002 | =back |
a5222a85 |
1003 | |
1004 | =head2 OS/2 |
1005 | |
1006 | [TODO - Ilya Zakharevich <ilya@math.ohio-state.edu>] |
1007 | |
1008 | =head2 VMS |
1009 | |
1010 | [TODO - Charles Bailey <bailey@newman.upenn.edu>] |
1011 | |
1012 | =head2 Win32 |
1013 | |
1014 | Site library searches failed to look for ".../site/5.XXX/lib" |
1015 | if ".../site/5.XXXYY/lib" wasn't found. This has been corrected. |
1016 | |
1017 | When given a pathname that consists only of a drivename, such |
1018 | as C<A:>, opendir() and stat() now use the current working |
1019 | directory for the drive rather than the drive root. |
1020 | |
1021 | The builtin XSUB functions in the Win32:: namespace are |
1022 | documented. See L<Win32>. |
1023 | |
1024 | $^X now contains the full path name of the running executable. |
1025 | |
1026 | A Win32::GetLongPathName() function is provided to complement |
1027 | Win32::GetFullPathName() and Win32::GetShortPathName(). See L<Win32>. |
1028 | |
1029 | POSIX::uname() is supported. |
1030 | |
1031 | system(1,...) now returns true process IDs rather than process |
1032 | handles. kill() accepts any real process id, rather than strictly |
1033 | return values from system(1,...). |
1034 | |
1035 | The C<Shell> module is supported. |
1036 | |
883d36a6 |
1037 | Rudimentary support for building under command.com in Windows 95 |
1038 | has been added. |
1039 | |
a5222a85 |
1040 | [TODO - GSAR] |
1041 | |
6c67e1bb |
1042 | =head1 New tests |
1043 | |
1044 | =over 4 |
1045 | |
09bef843 |
1046 | =item lib/attrs |
1047 | |
1048 | Compatibility tests for C<sub : attrs> vs the older C<use attrs>. |
1049 | |
1050 | =item lib/io_const |
6c67e1bb |
1051 | |
1052 | IO constants (SEEK_*, _IO*). |
14218588 |
1053 | |
09bef843 |
1054 | =item lib/io_dir |
6c67e1bb |
1055 | |
1056 | Directory-related IO methods (new, read, close, rewind, tied delete). |
1057 | |
09bef843 |
1058 | =item lib/io_multihomed |
6c67e1bb |
1059 | |
1060 | INET sockets with multi-homed hosts. |
1061 | |
09bef843 |
1062 | =item lib/io_poll |
6c67e1bb |
1063 | |
1064 | IO poll(). |
1065 | |
09bef843 |
1066 | =item lib/io_unix |
6c67e1bb |
1067 | |
1068 | UNIX sockets. |
1069 | |
09bef843 |
1070 | =item op/attrs |
1071 | |
1072 | Regression tests for C<my ($x,@y,%z) : attrs> and <sub : attrs>. |
1073 | |
6c67e1bb |
1074 | =item op/filetest |
1075 | |
1076 | File test operators. |
1077 | |
1078 | =item op/lex_assign |
1079 | |
5fdc711f |
1080 | Verify operations that access pad objects (lexicals and temporaries). |
6c67e1bb |
1081 | |
1082 | =back |
e02fdbd2 |
1083 | |
ba8251e8 |
1084 | =head1 Modules and Pragmata |
1085 | |
3e8c4fa0 |
1086 | =head2 Modules |
1087 | |
b7d8191e |
1088 | =over 4 |
1089 | |
09bef843 |
1090 | =item attributes |
1091 | |
1092 | While used internally by Perl as a pragma, this module also |
1093 | provides a way to fetch subroutine and variable attributes. |
1094 | See L<attributes>. |
1095 | |
a5222a85 |
1096 | =item B |
1097 | |
501fbaef |
1098 | The Perl Compiler suite has been extensively reworked for this |
1099 | release. |
1100 | |
a5222a85 |
1101 | [TODO - Vishal Bhatia <vishal@gol.com>, |
1102 | Nick Ing-Simmons <nick@ni-s.u-net.com>] |
1103 | |
f29c64d6 |
1104 | =item ByteLoader |
1105 | |
a5222a85 |
1106 | The ByteLoader is a dedicated extension to generate and run |
f29c64d6 |
1107 | Perl bytecode. See L<ByteLoader>. |
1108 | |
a5222a85 |
1109 | =item constant |
1110 | |
1111 | References can now be used. See L<constant>. |
1112 | |
1113 | =item charnames |
1114 | |
1115 | change#4052 |
1116 | [TODO - Ilya Zakharevich <ilya@math.ohio-state.edu>] |
1117 | |
1118 | =item Data::Dumper |
1119 | |
1120 | A C<Maxdepth> setting can be specified to avoid venturing |
73b437c8 |
1121 | too deeply into deep data structures. See L<Data::Dumper>. |
a5222a85 |
1122 | |
1123 | Dumping C<qr//> objects works correctly. |
1124 | |
1125 | =item DB |
1126 | |
1127 | C<DB> is an experimental module that exposes a clean abstraction |
1128 | to Perl's debugging API. |
1129 | |
1130 | =item DB_File |
1131 | |
0536e0eb |
1132 | DB_File can now be built with Berkeley DB versions 1, 2 or 3. |
1133 | See C<ext/DB_File/Changes>. |
a5222a85 |
1134 | |
f29c64d6 |
1135 | =item Devel::DProf |
1136 | |
9e107c59 |
1137 | Devel::DProf, a Perl source code profiler has been added. See |
1138 | L<Devel::DProf> and L<dprofpp>. |
f29c64d6 |
1139 | |
b7d8191e |
1140 | =item Dumpvalue |
1141 | |
437784d6 |
1142 | The Dumpvalue module provides screen dumps of Perl data. |
b7d8191e |
1143 | |
1144 | =item Benchmark |
1145 | |
54e82ce5 |
1146 | Overall, Benchmark results exhibit lower average error and better timing |
1147 | accuracy. |
1148 | |
868cb350 |
1149 | You can now run tests for I<n> seconds instead of guessing the right |
14218588 |
1150 | number of tests to run: e.g. timethese(-5, ...) will run each |
1151 | code for at least 5 CPU seconds. Zero as the "number of repetitions" |
155776c0 |
1152 | means "for at least 3 CPU seconds". The output format has also |
14218588 |
1153 | changed. For example: |
155776c0 |
1154 | |
54e82ce5 |
1155 | use Benchmark;$x=3;timethese(-5,{a=>sub{$x*$x},b=>sub{$x**2}}) |
155776c0 |
1156 | |
1157 | will now output something like this: |
1158 | |
54e82ce5 |
1159 | Benchmark: running a, b, each for at least 5 CPU seconds... |
1160 | a: 5 wallclock secs ( 5.77 usr + 0.00 sys = 5.77 CPU) @ 200551.91/s (n=1156516) |
1161 | b: 4 wallclock secs ( 5.00 usr + 0.02 sys = 5.02 CPU) @ 159605.18/s (n=800686) |
155776c0 |
1162 | |
1163 | New features: "each for at least N CPU seconds...", "wallclock secs", |
1164 | and the "@ operations/CPU second (n=operations)". |
b7d8191e |
1165 | |
54e82ce5 |
1166 | timethese() now returns a reference to a hash of Benchmark objects containing |
1167 | the test results, keyed on the names of the tests. |
1168 | |
1169 | timethis() now returns the iterations field in the Benchmark result object |
1170 | instead of 0. |
1171 | |
1172 | timethese(), timethis(), and the new cmpthese() (see below) can also take |
1173 | a format specifier of 'none' to suppress output. |
1174 | |
1175 | A new function countit() is just like timeit() except that it takes a |
1176 | TIME instead of a COUNT. |
1177 | |
1178 | A new function cmpthese() prints a chart comparing the results of each test |
1179 | returned from a timethese() call. For each possible pair of tests, the |
1180 | percentage speed difference (iters/sec or seconds/iter) is shown. |
1181 | |
1182 | For other details, see L<Benchmark>. |
a5222a85 |
1183 | |
f505c983 |
1184 | =item Devel::Peek |
1185 | |
1186 | The Devel::Peek module provides access to the internal representation |
14218588 |
1187 | of Perl variables and data. It is a data debugging tool for the XS programmer. |
f505c983 |
1188 | |
a5222a85 |
1189 | =item ExtUtils::MakeMaker |
1190 | |
1191 | change#4135, also needs docs in module pod |
1192 | [TODO - Ilya Zakharevich <ilya@math.ohio-state.edu>] |
1193 | |
b7d8191e |
1194 | =item Fcntl |
1195 | |
1196 | More Fcntl constants added: F_SETLK64, F_SETLKW64, O_LARGEFILE for |
14218588 |
1197 | large (more than 4G) file access (64-bit support is not yet |
b7d8191e |
1198 | working, though, so no need to get overly excited), Free/Net/OpenBSD |
1199 | locking behaviour flags F_FLOCK, F_POSIX, Linux F_SHLCK, and |
1200 | O_ACCMODE: the mask of O_RDONLY, O_WRONLY, and O_RDWR. |
1201 | |
a5222a85 |
1202 | =item File::Compare |
1203 | |
1204 | A compare_text() function has been added, which allows custom |
1205 | comparison functions. See L<File::Compare>. |
1206 | |
1207 | =item File::Find |
1208 | |
1209 | File::Find now works correctly when the wanted() function is either |
1210 | autoloaded or is a symbolic reference. |
1211 | |
08cd8952 |
1212 | A bug that caused File::Find to lose track of the working directory |
a5222a85 |
1213 | when pruning top-level directories has been fixed. |
1214 | |
81793b90 |
1215 | File::Find now also supports several other options to control its |
1216 | behavior. It can follow symbolic links if the C<follow> option is |
1217 | specified. Enabling the C<no_chdir> option will make File::Find skip |
1218 | changing the current directory when walking directories. The C<untaint> |
1219 | flag can be useful when running with taint checks enabled. |
1220 | |
1221 | See L<File::Find>. |
1222 | |
becf2bd3 |
1223 | =item File::Glob |
1224 | |
52bb0670 |
1225 | This extension implements BSD-style file globbing. By default, |
1226 | it will also be used for the internal implementation of the glob() |
1227 | operator. See L<File::Glob>. |
becf2bd3 |
1228 | |
f505c983 |
1229 | =item File::Spec |
1230 | |
1231 | New methods have been added to the File::Spec module: devnull() returns |
19799a22 |
1232 | the name of the null device (/dev/null on Unix) and tmpdir() the name of |
14218588 |
1233 | the temp directory (normally /tmp on Unix). There are now also methods |
f505c983 |
1234 | to convert between absolute and relative filenames: abs2rel() and |
14218588 |
1235 | rel2abs(). For compatibility with operating systems that specify volume |
1236 | names in file paths, the splitpath(), splitdir(), and catdir() methods |
f505c983 |
1237 | have been added. |
1238 | |
1239 | =item File::Spec::Functions |
1240 | |
1241 | The new File::Spec::Functions modules provides a function interface |
14218588 |
1242 | to the File::Spec module. Allows shorthand |
f505c983 |
1243 | |
14218588 |
1244 | $fullname = catfile($dir1, $dir2, $file); |
f505c983 |
1245 | |
1246 | instead of |
1247 | |
14218588 |
1248 | $fullname = File::Spec->catfile($dir1, $dir2, $file); |
f505c983 |
1249 | |
a5222a85 |
1250 | =item Getopt::Long |
1251 | |
c6edd1b7 |
1252 | Getopt::Long licensing has changed to allow the Perl Artistic License |
1253 | as well as the GPL. It used to be GPL only, which got in the way of |
1254 | non-GPL applications that wanted to use Getopt::Long. |
1255 | |
1256 | Getopt::Long encourages the use of Pod::Usage to produce help |
1257 | messages. For example: |
1258 | |
1259 | use Getopt::Long; |
1260 | use Pod::Usage; |
1261 | my $man = 0; |
1262 | my $help = 0; |
1263 | GetOptions('help|?' => \$help, man => \$man) or pod2usage(2); |
1264 | pod2usage(1) if $help; |
1265 | pod2usage(-exitstatus => 0, -verbose => 2) if $man; |
1266 | |
1267 | __END__ |
1268 | |
1269 | =head1 NAME |
1270 | |
1271 | sample - Using GetOpt::Long and Pod::Usage |
1272 | |
1273 | =head1 SYNOPSIS |
1274 | |
1275 | sample [options] [file ...] |
1276 | |
1277 | Options: |
1278 | -help brief help message |
1279 | -man full documentation |
1280 | |
1281 | =head1 OPTIONS |
1282 | |
1283 | =over 8 |
1284 | |
1285 | =item B<-help> |
1286 | |
1287 | Print a brief help message and exits. |
1288 | |
1289 | =item B<-man> |
1290 | |
1291 | Prints the manual page and exits. |
1292 | |
1293 | =back |
1294 | |
1295 | =head1 DESCRIPTION |
1296 | |
1297 | B<This program> will read the given input file(s) and do someting |
1298 | useful with the contents thereof. |
1299 | |
1300 | =cut |
1301 | |
1302 | See L<Pod::Usage> for details. |
1303 | |
1304 | A bug that prevented the non-option call-back E<lt>E<gt> from being |
1305 | specified as the first argument has been fixed. |
1306 | |
1307 | To specify the characters E<lt> and E<gt> as option starters, use |
1308 | E<gt>E<lt>. Note, however, that changing option starters is strongly |
1309 | deprecated. |
a5222a85 |
1310 | |
1311 | =item IO |
1312 | |
1313 | write() and syswrite() will now accept a single-argument |
1314 | form of the call, for consistency with Perl's syswrite(). |
1315 | |
1316 | You can now create a TCP-based IO::Socket::INET without forcing |
1317 | a connect attempt. This allows you to configure its options |
1318 | (like making it non-blocking) and then call connect() manually. |
1319 | |
1320 | A bug that prevented the IO::Socket::protocol() accessor |
1321 | from ever returning the correct value has been corrected. |
1322 | |
1323 | =item JPL |
1324 | |
1325 | Java Perl Lingo is now distributed with Perl. See jpl/README |
1326 | for more information. |
1327 | |
883d36a6 |
1328 | =item lib |
1329 | |
1330 | C<use lib> now weeds out any trailing duplicate entries. |
1331 | C<no lib> removes all named entries. |
1332 | |
e16b8f49 |
1333 | =item Math::BigInt |
1334 | |
437784d6 |
1335 | The bitwise operations C<E<lt>E<lt>>, C<E<gt>E<gt>>, C<&>, C<|>, |
e16b8f49 |
1336 | and C<~> are now supported on bigints. |
1337 | |
b7d8191e |
1338 | =item Math::Complex |
7711098a |
1339 | |
14218588 |
1340 | The accessor methods Re, Im, arg, abs, rho, and theta can now also |
868cb350 |
1341 | act as mutators (accessor $z->Re(), mutator $z->Re(3)). |
b7d8191e |
1342 | |
1343 | =item Math::Trig |
1344 | |
14218588 |
1345 | A little bit of radial trigonometry (cylindrical and spherical), |
1346 | radial coordinate conversions, and the great circle distance were added. |
b7d8191e |
1347 | |
a5222a85 |
1348 | =item Pod::Parser |
1349 | |
1350 | [TODO - Brad Appleton <bradapp@enteract.com>] |
1351 | |
1352 | =item Pod::Text and Pod::Man |
1353 | |
1354 | [TODO - Russ Allbery <rra@stanford.edu>] |
1355 | |
f4b9d880 |
1356 | =item SDBM_File |
1357 | |
1358 | An EXISTS method has been added to this module (and sdbm_exists() has |
1359 | been added to the underlying sdbm library), so one can now call exists |
14218588 |
1360 | on an SDBM_File tied hash and get the correct result, rather than a |
f4b9d880 |
1361 | runtime error. |
1362 | |
a5222a85 |
1363 | A bug that may have caused data loss when more than one disk block |
1364 | happens to be read from the database in a single FETCH() has been |
1365 | fixed. |
1366 | |
06ef4121 |
1367 | =item Time::Local |
1368 | |
1369 | The timelocal() and timegm() functions used to silently return bogus |
437784d6 |
1370 | results when the date fell outside the machine's integer range. They |
a5222a85 |
1371 | now consistently croak() if the date falls in an unsupported range. |
06ef4121 |
1372 | |
8fe0a5c4 |
1373 | =item Win32 |
1374 | |
1375 | The error return value in list context has been changed for all functions |
14218588 |
1376 | that return a list of values. Previously these functions returned a list |
1377 | with a single element C<undef> if an error occurred. Now these functions |
1378 | return the empty list in these situations. This applies to the following |
8fe0a5c4 |
1379 | functions: |
1380 | |
14218588 |
1381 | Win32::FsType |
1382 | Win32::GetOSVersion |
8fe0a5c4 |
1383 | |
1384 | The remaining functions are unchanged and continue to return C<undef> on |
1385 | error even in list context. |
1386 | |
1387 | The Win32::SetLastError(ERROR) function has been added as a complement |
1388 | to the Win32::GetLastError() function. |
1389 | |
1390 | The new Win32::GetFullPathName(FILENAME) returns the full absolute |
14218588 |
1391 | pathname for FILENAME in scalar context. In list context it returns |
1392 | a two-element list containing the fully qualified directory name and |
501fbaef |
1393 | the filename. See L<Win32>. |
8fe0a5c4 |
1394 | |
9fe6733a |
1395 | =item DBM Filters |
1396 | |
1397 | A new feature called "DBM Filters" has been added to all the |
14218588 |
1398 | DBM modules--DB_File, GDBM_File, NDBM_File, ODBM_File, and SDBM_File. |
1399 | DBM Filters add four new methods to each DBM module: |
9fe6733a |
1400 | |
1401 | filter_store_key |
1402 | filter_store_value |
1403 | filter_fetch_key |
1404 | filter_fetch_value |
1405 | |
14218588 |
1406 | These can be used to filter key-value pairs before the pairs are |
9fe6733a |
1407 | written to the database or just after they are read from the database. |
1408 | See L<perldbmfilter> for further information. |
1409 | |
b7d8191e |
1410 | =back |
3e8c4fa0 |
1411 | |
1412 | =head2 Pragmata |
1413 | |
437784d6 |
1414 | C<use attrs> is now obsolete, and is only provided for |
09bef843 |
1415 | backward-compatibility. It's been replaced by the C<sub : attributes> |
1416 | syntax. See L<perlsub/"Subroutine Attributes"> and L<attributes>. |
1417 | |
14218588 |
1418 | C<use utf8> to enable UTF-8 and Unicode support. |
43165c05 |
1419 | |
1420 | C<use caller 'encoding'> allows modules to inherit pragmatic attributes |
1421 | from the caller's context. C<encoding> is currently the only supported |
1422 | attribute. |
9d73390d |
1423 | |
4438c4b7 |
1424 | Lexical warnings pragma, C<use warnings;>, to control optional warnings. |
a5222a85 |
1425 | See L<perllexwarn>. |
6c67e1bb |
1426 | |
67d3893f |
1427 | C<use filetest> to control the behaviour of filetests (C<-r> C<-w> |
1428 | ...). Currently only one subpragma implemented, "use filetest |
1429 | 'access';", that uses access(2) or equivalent to check permissions |
1430 | instead of using stat(2) as usual. This matters in filesystems |
1431 | where there are ACLs (access control lists): the stat(2) might lie, |
1432 | but access(2) knows better. |
6c67e1bb |
1433 | |
ba8251e8 |
1434 | =head1 Utility Changes |
1435 | |
a5222a85 |
1436 | =head2 h2ph |
1437 | |
1438 | [TODO - Kurt Starsinic <kstar@chapin.edu>] |
1439 | |
1440 | =head2 perlcc |
1441 | |
1442 | C<perlcc> now supports the C and Bytecode backends. By default, |
1443 | it generates output from the simple C backend rather than the |
1444 | optimized C backend. |
1445 | |
1446 | Support for non-Unix platforms has been improved. |
1447 | |
1448 | =head2 h2xs |
1449 | |
1450 | change#4232 |
1451 | [TODO - Ilya Zakharevich <ilya@math.ohio-state.edu>] |
e02fdbd2 |
1452 | |
ba8251e8 |
1453 | =head1 Documentation Changes |
1454 | |
5fdc711f |
1455 | =over 4 |
1456 | |
883d36a6 |
1457 | =item perlcompile.pod |
1458 | |
1459 | An introduction to using the Perl Compiler suite. |
1460 | |
c7c04614 |
1461 | =item perlfilter.pod |
1462 | |
1463 | An introduction to writing Perl source filters. |
1464 | |
883d36a6 |
1465 | =item perlhack.pod |
1466 | |
1467 | Some guidelines for hacking the Perl source code. |
1468 | |
5fdc711f |
1469 | =item perlopentut.pod |
f8284313 |
1470 | |
5fdc711f |
1471 | A tutorial on using open() effectively. |
1472 | |
1473 | =item perlreftut.pod |
1474 | |
1475 | A tutorial that introduces the essentials of references. |
1476 | |
14218588 |
1477 | =item perltootc.pod |
1478 | |
1479 | A tutorial on managing class data for object modules. |
1480 | |
5fdc711f |
1481 | =back |
e02fdbd2 |
1482 | |
73b437c8 |
1483 | =head1 New or Changed Diagnostics |
ba8251e8 |
1484 | |
a99ba403 |
1485 | =over 4 |
1486 | |
09bef843 |
1487 | =item "my sub" not yet implemented |
1488 | |
1489 | (F) Lexically scoped subroutines are not yet implemented. Don't try that |
1490 | yet. |
1491 | |
a99ba403 |
1492 | =item '!' allowed only after types %s |
1493 | |
1494 | (F) The '!' is allowed in pack() and unpack() only after certain types. |
1495 | See L<perlfunc/pack>. |
1496 | |
1497 | =item / cannot take a count |
1498 | |
1499 | (F) You had an unpack template indicating a counted-length string, |
1500 | but you have also specified an explicit size for the string. |
1501 | See L<perlfunc/pack>. |
1502 | |
1503 | =item / must be followed by a, A or Z |
1504 | |
1505 | (F) You had an unpack template indicating a counted-length string, |
1506 | which must be followed by one of the letters a, A or Z |
1507 | to indicate what sort of string is to be unpacked. |
1508 | See L<perlfunc/pack>. |
1509 | |
1510 | =item / must be followed by a*, A* or Z* |
1511 | |
437784d6 |
1512 | (F) You had a pack template indicating a counted-length string, |
a99ba403 |
1513 | Currently the only things that can have their length counted are a*, A* or Z*. |
1514 | See L<perlfunc/pack>. |
1515 | |
1516 | =item / must follow a numeric type |
1517 | |
1518 | (F) You had an unpack template that contained a '#', |
1519 | but this did not follow some numeric unpack specification. |
1520 | See L<perlfunc/pack>. |
1521 | |
a99ba403 |
1522 | =item /%s/: Unrecognized escape \\%c passed through |
1523 | |
1524 | (W) You used a backslash-character combination which is not recognized |
1525 | by Perl. This combination appears in an interpolated variable or a |
1028017a |
1526 | C<'>-delimited regular expression. The character was understood literally. |
1527 | |
1528 | =item /%s/: Unrecognized escape \\%c in character class passed through |
1529 | |
1530 | (W) You used a backslash-character combination which is not recognized |
1531 | by Perl inside character classes. The character was understood literally. |
a99ba403 |
1532 | |
1533 | =item /%s/ should probably be written as "%s" |
1534 | |
1535 | (W) You have used a pattern where Perl expected to find a string, |
437784d6 |
1536 | as in the first argument to C<join>. Perl will treat the true |
a99ba403 |
1537 | or false result of matching the pattern against $_ as the string, |
1538 | which is probably not what you had in mind. |
1539 | |
1540 | =item %s() called too early to check prototype |
1541 | |
1542 | (W) You've called a function that has a prototype before the parser saw a |
1543 | definition or declaration for it, and Perl could not check that the call |
1544 | conforms to the prototype. You need to either add an early prototype |
1545 | declaration for the subroutine in question, or move the subroutine |
1546 | definition ahead of the call to get proper prototype checking. Alternatively, |
1547 | if you are certain that you're calling the function correctly, you may put |
1548 | an ampersand before the name to avoid the warning. See L<perlsub>. |
1549 | |
09bef843 |
1550 | =item %s package attribute may clash with future reserved word: %s |
1551 | |
1552 | (W) A lowercase attribute name was used that had a package-specific handler. |
1553 | That name might have a meaning to Perl itself some day, even though it |
1554 | doesn't yet. Perhaps you should use a mixed-case attribute name, instead. |
1555 | See L<attributes>. |
1556 | |
a99ba403 |
1557 | =item (in cleanup) %s |
6b121555 |
1558 | |
a99ba403 |
1559 | (W) This prefix usually indicates that a DESTROY() method raised |
1560 | the indicated exception. Since destructors are usually called by |
1561 | the system at arbitrary points during execution, and often a vast |
1562 | number of times, the warning is issued only once for any number |
1563 | of failures that would otherwise result in the same message being |
1564 | repeated. |
1565 | |
1566 | Failure of user callbacks dispatched using the C<G_KEEPERR> flag |
1567 | could also result in this warning. See L<perlcall/G_KEEPERR>. |
1568 | |
1569 | =item <> should be quotes |
1570 | |
1571 | (F) You wrote C<require E<lt>fileE<gt>> when you should have written |
1572 | C<require 'file'>. |
1573 | |
1574 | =item Attempt to join self |
1575 | |
1576 | (F) You tried to join a thread from within itself, which is an |
1577 | impossible task. You may be joining the wrong thread, or you may |
1578 | need to move the join() to some other thread. |
1579 | |
1580 | =item Bad evalled substitution pattern |
1581 | |
1582 | (F) You've used the /e switch to evaluate the replacement for a |
1583 | substitution, but perl found a syntax error in the code to evaluate, |
1584 | most likely an unexpected right brace '}'. |
1585 | |
1586 | =item Bad realloc() ignored |
1587 | |
1588 | (S) An internal routine called realloc() on something that had never been |
1589 | malloc()ed in the first place. Mandatory, but can be disabled by |
1590 | setting environment variable C<PERL_BADFREE> to 1. |
1591 | |
1592 | =item Binary number > 0b11111111111111111111111111111111 non-portable |
1593 | |
1594 | (W) The binary number you specified is larger than 2**32-1 |
1595 | (4294967295) and therefore non-portable between systems. See |
1596 | L<perlport> for more on portability concerns. |
1597 | |
1598 | =item Bit vector size > 32 non-portable |
1599 | |
1600 | (W) Using bit vector sizes larger than 32 is non-portable. |
1601 | |
1602 | =item Buffer overflow in prime_env_iter: %s |
1603 | |
1604 | (W) A warning peculiar to VMS. While Perl was preparing to iterate over |
1605 | %ENV, it encountered a logical name or symbol definition which was too long, |
1606 | so it was truncated to the string shown. |
1607 | |
1608 | =item Can't check filesystem of script "%s" |
1609 | |
1610 | (P) For some reason you can't check the filesystem of the script for nosuid. |
1611 | |
0b5b802d |
1612 | =item Can't ignore signal CHLD, forcing to default |
1613 | |
1614 | (W) Perl has detected that it is being run with the SIGCHLD signal |
1615 | (sometimes known as SIGCLD) disabled. Since disabling this signal |
1616 | will interfere with proper determination of exit status of child |
1617 | processes, Perl has reset the signal to its default value. |
1618 | This situation typically indicates that the parent program under |
1619 | which Perl may be running (e.g. cron) is being very careless. |
1620 | |
a99ba403 |
1621 | =item Can't modify non-lvalue subroutine call |
1622 | |
437784d6 |
1623 | (F) Subroutines meant to be used in lvalue context should be declared as |
1624 | such, see L<perlsub/"Lvalue subroutines">. |
a99ba403 |
1625 | |
1626 | =item Can't read CRTL environ |
1627 | |
1628 | (S) A warning peculiar to VMS. Perl tried to read an element of %ENV |
1629 | from the CRTL's internal environment array and discovered the array was |
1630 | missing. You need to figure out where your CRTL misplaced its environ |
1631 | or define F<PERL_ENV_TABLES> (see L<perlvms>) so that environ is not searched. |
1632 | |
1633 | =item Can't remove %s: %s, skipping file |
1634 | |
1635 | (S) You requested an inplace edit without creating a backup file. Perl |
1636 | was unable to remove the original file to replace it with the modified |
1637 | file. The file was left unmodified. |
1638 | |
1639 | =item Can't return %s from lvalue subroutine |
1640 | |
1641 | (F) Perl detected an attempt to return illegal lvalues (such |
1642 | as temporary or readonly values) from a subroutine used as an lvalue. |
1643 | This is not allowed. |
1644 | |
1645 | =item Can't weaken a nonreference |
1646 | |
1647 | (F) You attempted to weaken something that was not a reference. Only |
1648 | references can be weakened. |
1649 | |
1650 | =item Character class [:%s:] unknown |
1651 | |
1652 | (F) The class in the character class [: :] syntax is unknown. |
437784d6 |
1653 | See L<perlre>. |
a99ba403 |
1654 | |
1655 | =item Character class syntax [%s] belongs inside character classes |
1656 | |
1657 | (W) The character class constructs [: :], [= =], and [. .] go |
1658 | I<inside> character classes, the [] are part of the construct, |
437784d6 |
1659 | for example: /[012[:alpha:]345]/. Note that [= =] and [. .] |
1660 | are not currently implemented; they are simply placeholders for |
1661 | future extensions. |
a99ba403 |
1662 | |
1663 | =item Constant is not %s reference |
1664 | |
1665 | (F) A constant value (perhaps declared using the C<use constant> pragma) |
1666 | is being dereferenced, but it amounts to the wrong type of reference. The |
1667 | message indicates the type of reference that was expected. This usually |
1668 | indicates a syntax error in dereferencing the constant value. |
1669 | See L<perlsub/"Constant Functions"> and L<constant>. |
1670 | |
1671 | =item constant(%s): %%^H is not localized |
1672 | |
1673 | (F) When setting compile-time-lexicalized hash %^H one should set the |
1674 | corresponding bit of $^H as well. |
1675 | |
1676 | =item constant(%s): %s |
1677 | |
1678 | (F) Compile-time-substitutions (such as overloaded constants and |
1679 | character names) were not correctly set up. |
1680 | |
1681 | =item defined(@array) is deprecated |
1682 | |
1683 | (D) defined() is not usually useful on arrays because it checks for an |
1684 | undefined I<scalar> value. If you want to see if the array is empty, |
1685 | just use C<if (@array) { # not empty }> for example. |
1686 | |
1687 | =item defined(%hash) is deprecated |
1688 | |
1689 | (D) defined() is not usually useful on hashes because it checks for an |
1690 | undefined I<scalar> value. If you want to see if the hash is empty, |
1691 | just use C<if (%hash) { # not empty }> for example. |
1692 | |
1693 | =item Did not produce a valid header |
1694 | |
1695 | See Server error. |
1696 | |
1697 | =item Document contains no data |
1698 | |
1699 | See Server error. |
1700 | |
1701 | =item entering effective %s failed |
1702 | |
1703 | (F) While under the C<use filetest> pragma, switching the real and |
1704 | effective uids or gids failed. |
6b121555 |
1705 | |
73b437c8 |
1706 | =item false [] range "%s" in regexp |
1707 | |
1708 | (W) A character class range must start and end at a literal character, not |
1709 | another character class like C<\d> or C<[:alpha:]>. The "-" in your false |
1710 | range is interpreted as a literal "-". Consider quoting the "-", "\-". |
1711 | See L<perlre>. |
1712 | |
af8c498a |
1713 | =item Filehandle %s opened only for output |
6b121555 |
1714 | |
af8c498a |
1715 | (W) You tried to read from a filehandle opened only for writing. If you |
437784d6 |
1716 | intended it to be a read/write filehandle, you needed to open it with |
af8c498a |
1717 | "+E<lt>" or "+E<gt>" or "+E<gt>E<gt>" instead of with "E<lt>" or nothing. If |
1718 | you intended only to read from the file, use "E<lt>". See |
1719 | L<perlfunc/open>. |
e02fdbd2 |
1720 | |
a99ba403 |
1721 | =item Hexadecimal number > 0xffffffff non-portable |
1722 | |
1723 | (W) The hexadecimal number you specified is larger than 2**32-1 |
1724 | (4294967295) and therefore non-portable between systems. See |
1725 | L<perlport> for more on portability concerns. |
1726 | |
1727 | =item Ill-formed CRTL environ value "%s" |
1728 | |
1729 | (W) A warning peculiar to VMS. Perl tried to read the CRTL's internal |
1730 | environ array, and encountered an element without the C<=> delimiter |
1731 | used to spearate keys from values. The element is ignored. |
1732 | |
1733 | =item Ill-formed message in prime_env_iter: |%s| |
1734 | |
1735 | (W) A warning peculiar to VMS. Perl tried to read a logical name |
1736 | or CLI symbol definition when preparing to iterate over %ENV, and |
1737 | didn't see the expected delimiter between key and value, so the |
1738 | line was ignored. |
1739 | |
1740 | =item Illegal binary digit %s |
1741 | |
437784d6 |
1742 | (F) You used a digit other than 0 or 1 in a binary number. |
a99ba403 |
1743 | |
1744 | =item Illegal binary digit %s ignored |
1745 | |
1746 | (W) You may have tried to use a digit other than 0 or 1 in a binary number. |
1747 | Interpretation of the binary number stopped before the offending digit. |
1748 | |
1749 | =item Illegal number of bits in vec |
1750 | |
1751 | (F) The number of bits in vec() (the third argument) must be a power of |
1752 | two from 1 to 32 (or 64, if your platform supports that). |
1753 | |
1754 | =item Integer overflow in %s number |
1755 | |
1756 | (W) The hexadecimal, octal or binary number you have specified either |
c6edd1b7 |
1757 | as a literal or as an argument to hex() or oct() is too big for your |
a99ba403 |
1758 | architecture, and has been converted to a floating point number. On a |
1759 | 32-bit architecture the largest hexadecimal, octal or binary number |
1760 | representable without overflow is 0xFFFFFFFF, 037777777777, or |
1761 | 0b11111111111111111111111111111111 respectively. Note that Perl |
1762 | transparently promotes all numbers to a floating point representation |
1763 | internally--subject to loss of precision errors in subsequent |
1764 | operations. |
1765 | |
09bef843 |
1766 | =item Invalid %s attribute: %s |
1767 | |
1768 | The indicated attribute for a subroutine or variable was not recognized |
1769 | by Perl or by a user-supplied handler. See L<attributes>. |
1770 | |
1771 | =item Invalid %s attributes: %s |
1772 | |
1773 | The indicated attributes for a subroutine or variable were not recognized |
1774 | by Perl or by a user-supplied handler. See L<attributes>. |
1775 | |
73b437c8 |
1776 | =item invalid [] range "%s" in regexp |
1777 | |
1778 | The offending range is now explicitly displayed. |
1779 | |
09bef843 |
1780 | =item Invalid separator character %s in attribute list |
1781 | |
1782 | (F) Something other than a comma or whitespace was seen between the |
1783 | elements of an attribute list. If the previous attribute |
1784 | had a parenthesised parameter list, perhaps that list was terminated |
1785 | too soon. See L<attributes>. |
1786 | |
a99ba403 |
1787 | =item Invalid separator character %s in subroutine attribute list |
1788 | |
1789 | (F) Something other than a comma or whitespace was seen between the |
1790 | elements of a subroutine attribute list. If the previous attribute |
1791 | had a parenthesised parameter list, perhaps that list was terminated |
1792 | too soon. |
1793 | |
1794 | =item leaving effective %s failed |
1795 | |
1796 | (F) While under the C<use filetest> pragma, switching the real and |
1797 | effective uids or gids failed. |
1798 | |
1799 | =item Lvalue subs returning %s not implemented yet |
1800 | |
1801 | (F) Due to limitations in the current implementation, array and hash |
1802 | values cannot be returned in subroutines used in lvalue context. |
1803 | See L<perlsub/"Lvalue subroutines">. |
1804 | |
1805 | =item Method %s not permitted |
1806 | |
1807 | See Server error. |
1808 | |
1809 | =item Missing %sbrace%s on \N{} |
1810 | |
1811 | (F) Wrong syntax of character name literal C<\N{charname}> within |
1812 | double-quotish context. |
1813 | |
06eaf0bc |
1814 | =item Missing command in piped open |
1815 | |
1816 | (W) You used the C<open(FH, "| command")> or C<open(FH, "command |")> |
1817 | construction, but the command was missing or blank. |
1818 | |
09bef843 |
1819 | =item Missing name in "my sub" |
1820 | |
1821 | (F) The reserved syntax for lexically scoped subroutines requires that they |
1822 | have a name with which they can be found. |
1823 | |
a99ba403 |
1824 | =item no UTC offset information; assuming local time is UTC |
1825 | |
1826 | (S) A warning peculiar to VMS. Perl was unable to find the local |
1827 | timezone offset, so it's assuming that local system time is equivalent |
1828 | to UTC. If it's not, define the logical name F<SYS$TIMEZONE_DIFFERENTIAL> |
1829 | to translate to the number of seconds which need to be added to UTC to |
1830 | get local time. |
1831 | |
1832 | =item Octal number > 037777777777 non-portable |
1833 | |
1834 | (W) The octal number you specified is larger than 2**32-1 (4294967295) |
1835 | and therefore non-portable between systems. See L<perlport> for more |
1836 | on portability concerns. |
1837 | |
1838 | See also L<perlport> for writing portable code. |
1839 | |
1840 | =item panic: del_backref |
1841 | |
1842 | (P) Failed an internal consistency check while trying to reset a weak |
1843 | reference. |
1844 | |
1845 | =item panic: kid popen errno read |
1846 | |
1847 | (F) forked child returned an incomprehensible message about its errno. |
1848 | |
1849 | =item panic: magic_killbackrefs |
1850 | |
1851 | (P) Failed an internal consistency check while trying to reset all weak |
1852 | references to an object. |
1853 | |
1854 | =item Possible Y2K bug: %s |
1855 | |
1856 | (W) You are concatenating the number 19 with another number, which |
1857 | could be a potential Year 2000 problem. |
1858 | |
1859 | =item Premature end of script headers |
1860 | |
1861 | See Server error. |
1862 | |
0b5b802d |
1863 | =item Repeat count in pack overflows |
1864 | |
1865 | (F) You can't specify a repeat count so large that it overflows |
1866 | your signed integers. See L<perlfunc/pack>. |
1867 | |
1868 | =item Repeat count in unpack overflows |
1869 | |
1870 | (F) You can't specify a repeat count so large that it overflows |
1871 | your signed integers. See L<perlfunc/unpack>. |
1872 | |
a99ba403 |
1873 | =item realloc() of freed memory ignored |
1874 | |
1875 | (S) An internal routine called realloc() on something that had already |
1876 | been freed. |
1877 | |
1878 | =item Reference is already weak |
1879 | |
1880 | (W) You have attempted to weaken a reference that is already weak. |
1881 | Doing so has no effect. |
1882 | |
1883 | =item setpgrp can't take arguments |
1884 | |
1885 | (F) Your system has the setpgrp() from BSD 4.2, which takes no arguments, |
1886 | unlike POSIX setpgid(), which takes a process ID and process group ID. |
1887 | |
1888 | =item Strange *+?{} on zero-length expression |
1889 | |
1890 | (W) You applied a regular expression quantifier in a place where it |
1891 | makes no sense, such as on a zero-width assertion. |
1892 | Try putting the quantifier inside the assertion instead. For example, |
1893 | the way to match "abc" provided that it is followed by three |
1894 | repetitions of "xyz" is C</abc(?=(?:xyz){3})/>, not C</abc(?=xyz){3}/>. |
1895 | |
1896 | =item switching effective %s is not implemented |
1897 | |
1898 | (F) While under the C<use filetest> pragma, we cannot switch the |
1899 | real and effective uids or gids. |
1900 | |
437784d6 |
1901 | =item This Perl can't reset CRTL environ elements (%s) |
a99ba403 |
1902 | |
1903 | =item This Perl can't set CRTL environ elements (%s=%s) |
1904 | |
1905 | (W) Warnings peculiar to VMS. You tried to change or delete an element |
1906 | of the CRTL's internal environ array, but your copy of Perl wasn't |
1907 | built with a CRTL that contained the setenv() function. You'll need to |
1908 | rebuild Perl with a CRTL that does, or redefine F<PERL_ENV_TABLES> (see |
1909 | L<perlvms>) so that the environ array isn't the target of the change to |
1910 | %ENV which produced the warning. |
1911 | |
1912 | =item Unknown open() mode '%s' |
1913 | |
437784d6 |
1914 | (F) The second argument of 3-argument open() is not among the list |
1915 | of valid modes: C<L<lt>>, C<L<gt>>, C<E<gt>E<gt>>, C<+L<lt>>, |
1916 | C<+L<gt>>, C<+E<gt>E<gt>>, C<-|>, C<|->. |
a99ba403 |
1917 | |
1918 | =item Unknown process %x sent message to prime_env_iter: %s |
1919 | |
1920 | (P) An error peculiar to VMS. Perl was reading values for %ENV before |
1921 | iterating over it, and someone else stuck a message in the stream of |
1922 | data Perl expected. Someone's very confused, or perhaps trying to |
1923 | subvert Perl's population of %ENV for nefarious purposes. |
1924 | |
af8c498a |
1925 | =item Unrecognized escape \\%c passed through |
1926 | |
1927 | (W) You used a backslash-character combination which is not recognized |
1028017a |
1928 | by Perl. The character was understood literally. |
af8c498a |
1929 | |
09bef843 |
1930 | =item Unterminated attribute parameter in attribute list |
1931 | |
1932 | (F) The lexer saw an opening (left) parenthesis character while parsing an |
1933 | attribute list, but the matching closing (right) parenthesis |
1934 | character was not found. You may need to add (or remove) a backslash |
1935 | character to get your parentheses to balance. See L<attributes>. |
1936 | |
1937 | =item Unterminated attribute list |
1938 | |
1939 | (F) The lexer found something other than a simple identifier at the start |
1940 | of an attribute, and it wasn't a semicolon or the start of a |
1941 | block. Perhaps you terminated the parameter list of the previous attribute |
1942 | too soon. See L<attributes>. |
1943 | |
09bef843 |
1944 | =item Unterminated attribute parameter in subroutine attribute list |
1945 | |
1946 | (F) The lexer saw an opening (left) parenthesis character while parsing a |
1947 | subroutine attribute list, but the matching closing (right) parenthesis |
1948 | character was not found. You may need to add (or remove) a backslash |
1949 | character to get your parentheses to balance. |
1950 | |
1951 | =item Unterminated subroutine attribute list |
1952 | |
1953 | (F) The lexer found something other than a simple identifier at the start |
1954 | of a subroutine attribute, and it wasn't a semicolon or the start of a |
1955 | block. Perhaps you terminated the parameter list of the previous attribute |
1956 | too soon. |
1957 | |
a99ba403 |
1958 | =item Value of CLI symbol "%s" too long |
eb6e2d6f |
1959 | |
a99ba403 |
1960 | (W) A warning peculiar to VMS. Perl tried to read the value of an %ENV |
1961 | element from a CLI symbol table, and found a resultant string longer |
1962 | than 1024 characters. The return value has been truncated to 1024 |
1963 | characters. |
eb6e2d6f |
1964 | |
a99ba403 |
1965 | =item Version number must be a constant number |
ba8251e8 |
1966 | |
a99ba403 |
1967 | (P) The attempt to translate a C<use Module n.n LIST> statement into |
1968 | its equivalent C<BEGIN> block found an internal inconsistency with |
1969 | the version number. |
1970 | |
1971 | =back |
27806c82 |
1972 | |
a5222a85 |
1973 | =head1 Obsolete Diagnostics |
3175b8cd |
1974 | |
a99ba403 |
1975 | =over 4 |
1976 | |
1977 | =item Character class syntax [: :] is reserved for future extensions |
1978 | |
1979 | (W) Within regular expression character classes ([]) the syntax beginning |
1980 | with "[:" and ending with ":]" is reserved for future extensions. |
1981 | If you need to represent those character sequences inside a regular |
1982 | expression character class, just quote the square brackets with the |
1983 | backslash: "\[:" and ":\]". |
1984 | |
1985 | =item Ill-formed logical name |%s| in prime_env_iter |
1986 | |
1987 | (W) A warning peculiar to VMS. A logical name was encountered when preparing |
1988 | to iterate over %ENV which violates the syntactic rules governing logical |
1989 | names. Because it cannot be translated normally, it is skipped, and will not |
1990 | appear in %ENV. This may be a benign occurrence, as some software packages |
1991 | might directly modify logical name tables and introduce nonstandard names, |
1992 | or it may indicate that a logical name table has been corrupted. |
1993 | |
1994 | =item regexp too big |
1995 | |
1996 | (F) The current implementation of regular expressions uses shorts as |
1997 | address offsets within a string. Unfortunately this means that if |
1998 | the regular expression compiles to longer than 32767, it'll blow up. |
1999 | Usually when you want a regular expression this big, there is a better |
2000 | way to do it with multiple statements. See L<perlre>. |
2001 | |
2002 | =item Use of "$$<digit>" to mean "${$}<digit>" is deprecated |
2003 | |
2004 | (D) Perl versions before 5.004 misinterpreted any type marker followed |
2005 | by "$" and a digit. For example, "$$0" was incorrectly taken to mean |
2006 | "${$}0" instead of "${$0}". This bug is (mostly) fixed in Perl 5.004. |
2007 | |
2008 | However, the developers of Perl 5.004 could not fix this bug completely, |
2009 | because at least two widely-used modules depend on the old meaning of |
2010 | "$$0" in a string. So Perl 5.004 still interprets "$$<digit>" in the |
2011 | old (broken) way inside strings; but it generates this message as a |
2012 | warning. And in Perl 5.005, this special treatment will cease. |
2013 | |
2014 | =back |
3175b8cd |
2015 | |
ba8251e8 |
2016 | =head1 BUGS |
2017 | |
437784d6 |
2018 | If you find what you think is a bug, you might check the |
14218588 |
2019 | articles recently posted to the comp.lang.perl.misc newsgroup. |
ba8251e8 |
2020 | There may also be information at http://www.perl.com/perl/, the Perl |
2021 | Home Page. |
2022 | |
2023 | If you believe you have an unreported bug, please run the B<perlbug> |
14218588 |
2024 | program included with your release. Make sure to trim your bug down |
ba8251e8 |
2025 | to a tiny but sufficient test case. Your bug report, along with the |
14218588 |
2026 | output of C<perl -V>, will be sent off to perlbug@perl.com to be |
ba8251e8 |
2027 | analysed by the Perl porting team. |
2028 | |
2029 | =head1 SEE ALSO |
2030 | |
2031 | The F<Changes> file for exhaustive details on what changed. |
2032 | |
2033 | The F<INSTALL> file for how to build Perl. |
2034 | |
2035 | The F<README> file for general stuff. |
2036 | |
2037 | The F<Artistic> and F<Copying> files for copyright information. |
2038 | |
2039 | =head1 HISTORY |
2040 | |
a5222a85 |
2041 | Written by Gurusamy Sarathy <F<gsar@activestate.com>>, with many |
2042 | contributions from The Perl Porters. |
ba8251e8 |
2043 | |
2044 | Send omissions or corrections to <F<perlbug@perl.com>>. |
2045 | |
2046 | =cut |