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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 CHECK is a new keyword |
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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<CHECK> are now special. These are queued up during |
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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 | =item Semantics of bareword prototype C<(*)> have changed |
153 | |
154 | Arguments prototyped as C<*> will now be visible within the subroutine |
155 | as either a simple scalar or as a reference to a typeglob. Perl 5.005 |
156 | always coerced simple scalar arguments to a typeglob, which wasn't useful |
157 | in situations where the subroutine must distinguish between a simple |
158 | scalar and a typeglob. See L<perlsub/Prototypes>. |
159 | |
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160 | =back |
161 | |
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162 | =head2 C Source Incompatibilities |
163 | |
164 | =over 4 |
165 | |
166 | =item C<PERL_POLLUTE> |
167 | |
168 | Release 5.005 grandfathered old global symbol names by providing preprocessor |
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169 | macros for extension source compatibility. As of release 5.6, these |
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170 | preprocessor definitions are not available by default. You need to explicitly |
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171 | compile perl with C<-DPERL_POLLUTE> to get these definitions. For |
172 | extensions still using the old symbols, this option can be |
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173 | specified via MakeMaker: |
174 | |
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175 | perl Makefile.PL POLLUTE=1 |
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176 | |
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177 | =item C<PERL_IMPLICIT_CONTEXT> |
178 | |
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179 | PERL_IMPLICIT_CONTEXT is automatically enabled whenever Perl is built |
180 | with one of -Dusethreads, -Dusemultiplicity, or both. It is not |
181 | intended to be enabled by users at this time. |
182 | |
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183 | This new build option provides a set of macros for all API functions |
184 | such that an implicit interpreter/thread context argument is passed to |
185 | every API function. As a result of this, something like C<sv_setsv(foo,bar)> |
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186 | amounts to a macro invocation that actually translates to something like |
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187 | C<Perl_sv_setsv(my_perl,foo,bar)>. While this is generally expected |
188 | to not have any significant source compatibility issues, the difference |
189 | between a macro and a real function call will need to be considered. |
190 | |
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191 | This means that there B<is> a source compatibility issue as a result of |
192 | this if your extensions attempt to use pointers to any of the Perl API |
193 | functions. |
194 | |
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195 | Note that the above issue is not relevant to the default build of |
196 | Perl, whose interfaces continue to match those of prior versions |
197 | (but subject to the other options described here). |
198 | |
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199 | See L<perlguts/"The Perl API"> for detailed information on the |
200 | ramifications of building Perl using this option. |
201 | |
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202 | =item C<PERL_POLLUTE_MALLOC> |
203 | |
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204 | Enabling Perl's malloc in release 5.005 and earlier caused |
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205 | the namespace of system versions of the malloc family of functions to |
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206 | be usurped by the Perl versions, since by default they used the |
207 | same names. |
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208 | |
209 | Besides causing problems on platforms that do not allow these functions to |
210 | be cleanly replaced, this also meant that the system versions could not |
211 | be called in programs that used Perl's malloc. Previous versions of Perl |
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212 | have allowed this behaviour to be suppressed with the HIDEMYMALLOC and |
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213 | EMBEDMYMALLOC preprocessor definitions. |
214 | |
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215 | As of release 5.6, Perl's malloc family of functions have default names |
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216 | distinct from the system versions. You need to explicitly compile perl with |
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217 | C<-DPERL_POLLUTE_MALLOC> to get the older behaviour. HIDEMYMALLOC |
218 | and EMBEDMYMALLOC have no effect, since the behaviour they enabled is now |
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219 | the default. |
220 | |
221 | Note that these functions do B<not> constitute Perl's memory allocation API. |
222 | See L<perlguts/"Memory Allocation"> for further information about that. |
223 | |
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224 | =back |
225 | |
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226 | =head2 Compatible C Source API Changes |
227 | |
228 | =over |
229 | |
230 | =item C<PATCHLEVEL> is now C<PERL_VERSION> |
231 | |
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232 | The cpp macros C<PERL_REVISION>, C<PERL_VERSION>, and C<PERL_SUBVERSION> |
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233 | are now available by default from perl.h, and reflect the base revision, |
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234 | patchlevel, and subversion respectively. C<PERL_REVISION> had no |
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235 | prior equivalent, while C<PERL_VERSION> and C<PERL_SUBVERSION> were |
236 | previously available as C<PATCHLEVEL> and C<SUBVERSION>. |
237 | |
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238 | The new names cause less pollution of the B<cpp> namespace and reflect what |
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239 | the numbers have come to stand for in common practice. For compatibility, |
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240 | the old names are still supported when F<patchlevel.h> is explicitly |
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241 | included (as required before), so there is no source incompatibility |
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242 | from the change. |
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243 | |
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244 | =item Support for C++ exceptions |
245 | |
246 | change#3386, also needs perlguts documentation |
247 | [TODO - Chip Salzenberg <chip@perlsupport.com>] |
248 | |
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249 | =back |
250 | |
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251 | =head2 Binary Incompatibilities |
252 | |
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253 | The default build of this release is binary compatible with the 5.005 |
254 | release or its maintenance versions. |
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255 | |
256 | The usethreads or usemultiplicity builds are B<not> binary compatible |
257 | with the corresponding builds in 5.005. |
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258 | |
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259 | =head1 Installation and Configuration Improvements |
260 | |
261 | =head2 New Configure flags |
262 | |
263 | The following new flags may be enabled on the Configure command line |
264 | by running Configure with C<-Dflag>. |
265 | |
266 | usemultiplicity |
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267 | |
268 | uselongdouble |
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269 | usemorebits |
270 | uselargefiles |
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271 | |
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272 | =head2 -Dusethreads and -Duse64bits now more daring |
273 | |
274 | The Configure options enabling the use of threads and the use of |
275 | 64-bitness are now more daring in the sense that they no more have |
276 | an explicit list of operating systems of known threads/64-bit |
277 | capabilities. In other words: if your operating system has the |
278 | necessary APIs, you should be able just to go ahead and use them. |
279 | See also L<"64-bit support">. |
280 | |
281 | =head2 Long Doubles |
282 | |
283 | Some platforms have "long doubles", floating point numbers of even |
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284 | larger range than ordinary "doubles". To enable using long doubles for |
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285 | Perl's scalars, use -Duselongdouble. |
286 | |
287 | =head2 -Dusemorebits |
288 | |
289 | You can enable both -Duse64bits and -Dlongdouble by -Dusemorebits. |
290 | See also L<"64-bit support">. |
291 | |
292 | =head2 -Duselargefiles |
293 | |
294 | Some platforms support large files, files larger than two gigabytes. |
295 | See L<"Large file support"> for more information. |
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296 | |
297 | =head2 installusrbinperl |
298 | |
299 | You can use "Configure -Uinstallusrbinperl" which causes installperl |
300 | to skip installing perl also as /usr/bin/perl. This is useful if you |
301 | prefer not to modify /usr/bin for some reason or another but harmful |
302 | because many scripts assume to find Perl in /usr/bin/perl. |
303 | |
304 | =head2 SOCKS support |
305 | |
306 | You can use "Configure -Dusesocks" which causes Perl to probe |
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307 | for the SOCKS (v5, not v4) proxy protocol library, |
308 | http://www.socks.nec.com/ |
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309 | |
310 | =head2 C<-A> flag |
311 | |
312 | You can "post-edit" the Configure variables using the Configure C<-A> |
313 | flag. The editing happens immediately after the platform specific |
314 | hints files have been processed but before the actual configuration |
315 | process starts. Run C<Configure -h> to find out the full C<-A> syntax. |
316 | |
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317 | =head2 Enhanced Installation Directories |
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318 | |
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319 | The installation structure has been enriched to improve the support for |
320 | maintaining multiple versions of perl, to provide locations for |
321 | vendor-supplied modules and scripts, and to ease maintenance of |
322 | locally-added modules and scripts. See the section on Installation |
323 | Directories in the INSTALL file for complete details. For most users |
324 | building and installing from source, the defaults should be fine. |
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325 | |
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326 | =head1 Core Changes |
327 | |
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328 | =head2 Unicode and UTF-8 support |
329 | |
330 | Perl can optionally use UTF-8 as its internal representation for character |
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331 | strings. The C<utf8> pragma enables this support in the current lexical |
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332 | scope. See L<utf8> for more information. |
333 | |
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334 | =head2 Interpreter threads |
335 | |
336 | WARNING: This is an experimental feature in a pre-alpha state. Use |
337 | at your own risk. |
338 | |
339 | Perl 5.005_63 introduces the beginnings of support for running multiple |
340 | interpreters concurrently in different threads. In conjunction with |
341 | the perl_clone() API call, which can be used to selectively duplicate |
342 | the state of any given interpreter, it is possible to compile a |
343 | piece of code once in an interpreter, clone that interpreter |
344 | one or more times, and run all the resulting interpreters in distinct |
345 | threads. |
346 | |
347 | On Windows, this feature is used to emulate fork() at the interpreter |
348 | level. See L<perlfork>. |
349 | |
350 | This feature is still in evolution. It is eventually meant to be used |
351 | to selectively clone a subroutine and data reachable from that |
352 | subroutine in a separate interpreter and run the cloned subroutine |
353 | in a separate thread. Since there is no shared data between the |
354 | interpreters, little or no locking will be needed (unless parts of |
355 | the symbol table are explicitly shared). This is obviously intended |
356 | to be an easy-to-use replacement for the existing threads support. |
357 | |
358 | Support for cloning interpreters must currently be manually enabled |
359 | by defining the cpp macro USE_ITHREADS on non-Windows platforms. |
360 | (See win32/Makefile for how to enable it on Windows.) The resulting |
361 | perl executable will be functionally identical to one that was built |
362 | without USE_ITHREADS, but the perl_clone() API call will only be |
363 | available in the former. |
364 | |
365 | USE_ITHREADS enables Perl source code changes that provide a clear |
366 | separation between the op tree and the data it operates with. The |
367 | former is considered immutable, and can therefore be shared between |
368 | an interpreter and all of its clones, while the latter is considered |
369 | local to each interpreter, and is therefore copied for each clone. |
370 | |
371 | Note that building Perl with the -Dusemultiplicity Configure option |
372 | is adequate if you wish to run multiple B<independent> interpreters |
373 | concurrently in different threads. USE_ITHREADS only needs to be |
374 | enabled if you wish to obtain access to perl_clone() and cloned |
375 | interpreters. |
376 | |
377 | [XXX TODO - the Compiler backends may be broken when USE_ITHREADS is |
378 | enabled.] |
379 | |
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380 | =head2 Lexically scoped warning categories |
381 | |
382 | You can now control the granularity of warnings emitted by perl at a finer |
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383 | level using the C<use warnings> pragma. See L<warnings> and L<perllexwarn> |
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384 | for details. |
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385 | |
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386 | =head2 Lvalue subroutines |
387 | |
388 | WARNING: This is an experimental feature. |
389 | |
390 | change#4081 |
391 | [TODO - Ilya Zakharevich <ilya@math.ohio-state.edu>, |
392 | Tuomas Lukka <lukka@fas.harvard.edu>)] |
393 | |
394 | =head2 "our" declarations |
395 | |
396 | An "our" declaration introduces a value that can be best understood |
397 | as a lexically scoped symbolic alias to a global variable in the |
398 | current package. This is mostly useful as an alternative to the |
399 | C<vars> pragma, but also provides the opportunity to introduce |
400 | typing and other attributes for such variables. See L<perlfunc/our>. |
401 | |
402 | =head2 Weak references |
403 | |
404 | WARNING: This is an experimental feature. |
405 | |
406 | change#3385, also need perlguts documentation |
407 | |
408 | [TODO - Tuomas Lukka <lukka@fas.harvard.edu>] |
409 | |
becf2bd3 |
410 | =head2 File globbing implemented internally |
411 | |
412 | WARNING: This is currently an experimental feature. Interfaces and |
413 | implementation are likely to change. |
414 | |
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415 | Perl now uses the File::Glob implementation of the glob() operator |
416 | automatically. This avoids using an external csh process and the |
417 | problems associated with it. |
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418 | |
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419 | =head2 Binary numbers supported |
420 | |
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421 | Binary numbers are now supported as literals, in s?printf formats, and |
422 | C<oct()>: |
423 | |
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424 | $answer = 0b101010; |
425 | printf "The answer is: %b\n", oct("0b101010"); |
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426 | |
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427 | =head2 Some arrows may be omitted in calls through references |
428 | |
429 | Perl now allows the arrow to be omitted in many constructs |
430 | involving subroutine calls through references. For example, |
431 | C<$foo[10]->('foo')> may now be written C<$foo[10]('foo')>. |
432 | This is rather similar to how the arrow may be omitted from |
433 | C<$foo[10]->{'foo'}>. Note however, that the arrow is still |
434 | required for C<foo(10)->('bar')>. |
435 | |
afebc493 |
436 | =head2 exists() is supported on subroutine names |
437 | |
438 | The exists() builtin now works on subroutine names. A subroutine |
439 | is considered to exist if it has been declared (even if implicitly). |
440 | See L<perlfunc/exists> for examples. |
441 | |
01020589 |
442 | =head2 exists() and delete() are supported on array elements |
443 | |
444 | The exists() and delete() builtins now work on simple arrays as well. |
445 | The behavior is similar to that on hash elements. |
446 | |
8ea97a1e |
447 | exists() can be used to check whether an array element has been |
448 | initialized without autovivifying it. If the array is tied, the |
449 | EXISTS() method in the corresponding tied package will be invoked. |
450 | |
451 | delete() may be used to remove an element from the array and return |
452 | it. The array element at that position returns to its unintialized |
453 | state, so that testing for the same element with exists() will return |
454 | false. If the element happens to be the one at the end, the size of |
455 | the array also shrinks by one. If the array is tied, the DELETE() method |
01020589 |
456 | in the corresponding tied package will be invoked. |
457 | |
458 | See L<perlfunc/exists> and L<perlfunc/delete> for examples. |
459 | |
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460 | =head2 syswrite() ease-of-use |
461 | |
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462 | The length argument of C<syswrite()> has become optional. |
463 | |
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464 | =head2 File and directory handles can be autovivified |
a5222a85 |
465 | |
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466 | Similar to how constructs such as C<$x->[0]> autovivify a reference, |
b1a9ed4a |
467 | handle constructors (open(), opendir(), pipe(), socketpair(), sysopen(), |
468 | socket(), and accept()) now autovivify a file or directory handle |
469 | if the handle passed to them is an uninitialized scalar variable. This |
470 | allows the constructs such as C<open(my $fh, ...)> and C<open(local $fh,...)> |
471 | to be used to create filehandles that will conveniently be closed |
472 | automatically when the scope ends, provided there are no other references |
473 | to them. This largely eliminates the need for typeglobs when opening |
474 | filehandles that must be passed around, as in the following example: |
a5222a85 |
475 | |
476 | sub myopen { |
477 | open my $fh, "@_" |
478 | or die "Can't open '@_': $!"; |
479 | return $fh; |
480 | } |
481 | |
482 | { |
483 | my $f = myopen("</etc/motd"); |
484 | print <$f>; |
485 | # $f implicitly closed here |
486 | } |
487 | |
488 | [TODO - this idiom needs more pod penetration] |
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489 | |
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490 | =head2 64-bit support |
491 | |
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492 | All platforms that have 64-bit integers either (a) natively as longs |
493 | or ints (b) via special compiler flags (c) using long long are able to |
494 | use "quads" (64-integers) as follows: |
495 | |
496 | =over 4 |
497 | |
a5222a85 |
498 | =item * |
499 | |
500 | constants (decimal, hexadecimal, octal, binary) in the code |
501 | |
502 | =item * |
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503 | |
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504 | arguments to oct() and hex() |
9c107f78 |
505 | |
a5222a85 |
506 | =item * |
507 | |
508 | arguments to print(), printf() and sprintf() (flag prefixes ll, L, q) |
509 | |
510 | =item * |
9c107f78 |
511 | |
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512 | printed as such |
9c107f78 |
513 | |
a5222a85 |
514 | =item * |
515 | |
516 | pack() and unpack() "q" and "Q" formats |
517 | |
518 | =item * |
519 | |
520 | in basic arithmetics: + - * / % |
521 | |
522 | =item * |
1fad5d67 |
523 | |
a5222a85 |
524 | vec() (but see the below note about bit arithmetics) |
9c107f78 |
525 | |
526 | =back |
527 | |
528 | Note that unless you have the case (a) you will have to configure |
529 | and compile Perl using the -Duse64bits Configure flag. |
530 | |
3175b8cd |
531 | Unfortunately bit arithmetics (&, |, ^, ~, <<, >>) for numbers are not |
532 | 64-bit clean, they are explictly forced to be 32-bit. Bit arithmetics |
533 | for bit vectors (created by vec()) are not limited in their width. |
d0ba1bd2 |
534 | |
2d4389e4 |
535 | Last but not least: note that due to Perl's habit of always using |
d0ba1bd2 |
536 | floating point numbers the quads are still not true integers. |
537 | When quads overflow their limits (0...18_446_744_073_709_551_615 unsigned, |
538 | -9_223_372_036_854_775_808...9_223_372_036_854_775_807 signed), they |
539 | are silently promoted to floating point numbers, after which they will |
540 | start losing precision (their lower digits). |
2d4389e4 |
541 | |
542 | =head2 Large file support |
543 | |
544 | If you have filesystems that support "large files" (files larger than |
aa855319 |
545 | 2 gigabytes), you may now also be able to create and access them from |
249b38c6 |
546 | Perl. You have to use Configure -Duselargefiles. Turning on the |
822ba51d |
547 | large file support turns on also the 64-bit support on many platforms. |
548 | Beware that unless your filesystem also supports "sparse files" seeking |
549 | to umpteen petabytes may be unadvisable. |
2d4389e4 |
550 | |
eed7fde4 |
551 | Note that in addition to requiring a proper file system to do large |
552 | files you may also need to adjust your per-process (or your |
553 | per-system, or per-process-group, or per-user-group) maximum filesize |
554 | limits before running Perl scripts that try to handle large files, |
555 | especially if you intend to write such files. |
556 | |
557 | Finally, in addition to your process/process group maximum filesize |
558 | limits, you may have quota limits on your filesystems that stop you |
559 | (your user id or your user group id) from using large files. |
560 | |
561 | Adjusting your process/user/group/file system/operating system limits |
562 | is outside the scope of Perl core language. For process limits, you |
563 | may try increasing the limits using your shell's limits/limit/ulimit |
564 | command before running Perl. The BSD::Resource extension (not |
565 | included with the standard Perl distribution) may also be of use, it |
566 | offers the getrlimit/setrlimit interface that can be used to adjust |
567 | process resource usage limits, including the maximum filesize limit. |
475d79b5 |
568 | |
aa855319 |
569 | =head2 Long doubles |
570 | |
571 | In some systems you may be able to use long doubles to enhance the |
822ba51d |
572 | range and precision of your double precision floating point numbers |
aa855319 |
573 | (that is, Perl's numbers). Use Configure -Duselongdouble to enable |
574 | this support (if it is available). |
575 | |
576 | =head2 "more bits" |
577 | |
822ba51d |
578 | You can "Configure -Dusemorebits" to turn on both the 64-bit support |
aa855319 |
579 | and the long double support. |
09bef843 |
580 | |
43481408 |
581 | =head2 Enhanced support for sort() subroutines |
582 | |
583 | Perl subroutines with a prototype of C<($$)> and XSUBs in general can |
584 | now be used as sort subroutines. In either case, the two elements to |
af365420 |
585 | be compared are passed as normal parameters in @_. See L<perlfunc/sort>. |
43481408 |
586 | |
587 | For unprototyped sort subroutines, the historical behavior of passing |
588 | the elements to be compared as the global variables $a and $b remains |
589 | unchanged. |
590 | |
62c18ce2 |
591 | =head2 Better syntax checks on parenthesized unary operators |
592 | |
593 | Expressions such as: |
594 | |
14218588 |
595 | print defined(&foo,&bar,&baz); |
596 | print uc("foo","bar","baz"); |
597 | undef($foo,&bar); |
62c18ce2 |
598 | |
7711098a |
599 | used to be accidentally allowed in earlier versions, and produced |
14218588 |
600 | unpredictable behaviour. Some produced ancillary warnings |
601 | when used in this way; others silently did the wrong thing. |
62c18ce2 |
602 | |
603 | The parenthesized forms of most unary operators that expect a single |
14218588 |
604 | argument now ensure that they are not called with more than one |
605 | argument, making the cases shown above syntax errors. The usual |
606 | behaviour of: |
62c18ce2 |
607 | |
14218588 |
608 | print defined &foo, &bar, &baz; |
609 | print uc "foo", "bar", "baz"; |
610 | undef $foo, &bar; |
62c18ce2 |
611 | |
612 | remains unchanged. See L<perlop>. |
613 | |
3e3318e7 |
614 | =head2 POSIX character class syntax [: :] supported |
615 | |
616 | For example to match alphabetic characters use /[[:alpha:]]/. |
617 | See L<perlre> for details. |
618 | |
5a929a98 |
619 | =head2 Improved C<qw//> operator |
8127e0e3 |
620 | |
26ef7447 |
621 | The C<qw//> operator is now evaluated at compile time into a true list |
622 | instead of being replaced with a run time call to C<split()>. This |
14218588 |
623 | removes the confusing misbehaviour of C<qw//> in scalar context, which |
624 | had inherited that behaviour from split(). |
26ef7447 |
625 | |
626 | Thus: |
627 | |
628 | $foo = ($bar) = qw(a b c); print "$foo|$bar\n"; |
629 | |
630 | now correctly prints "3|a", instead of "2|a". |
8127e0e3 |
631 | |
5a929a98 |
632 | =head2 pack() format 'Z' supported |
633 | |
634 | The new format type 'Z' is useful for packing and unpacking null-terminated |
635 | strings. See L<perlfunc/"pack">. |
636 | |
4d0c1c44 |
637 | =head2 pack() format modifier '!' supported |
ee3907e2 |
638 | |
14218588 |
639 | The new format type modifier '!' is useful for packing and unpacking |
ee3907e2 |
640 | native shorts, ints, and longs. See L<perlfunc/"pack">. |
641 | |
f29c64d6 |
642 | =head2 pack() and unpack() support counted strings |
643 | |
a5222a85 |
644 | The template character '/' can be used to specify a counted string |
f29c64d6 |
645 | type to be packed or unpacked. See L<perlfunc/"pack">. |
646 | |
a5222a85 |
647 | =head2 Comments in pack() templates |
648 | |
649 | The '#' character in a template introduces a comment up to |
650 | end of the line. This facilitates documentation of pack() |
651 | templates. |
652 | |
2b92dfce |
653 | =head2 $^X variables may now have names longer than one character |
654 | |
655 | Formerly, $^X was synonymous with ${"\cX"}, but $^XY was a syntax |
656 | error. Now variable names that begin with a control character may be |
657 | arbitrarily long. However, for compatibility reasons, these variables |
658 | I<must> be written with explicit braces, as C<${^XY}> for example. |
14218588 |
659 | C<${^XYZ}> is synonymous with ${"\cXYZ"}. Variable names with more |
2b92dfce |
660 | than one control character, such as C<${^XY^Z}>, are illegal. |
661 | |
14218588 |
662 | The old syntax has not changed. As before, `^X' may be either a |
663 | literal control-X character or the two-character sequence `caret' plus |
664 | `X'. When braces are omitted, the variable name stops after the |
2b92dfce |
665 | control character. Thus C<"$^XYZ"> continues to be synonymous with |
7711098a |
666 | C<$^X . "YZ"> as before. |
2b92dfce |
667 | |
668 | As before, lexical variables may not have names beginning with control |
669 | characters. As before, variables whose names begin with a control |
14218588 |
670 | character are always forced to be in package `main'. All such variables |
671 | are reserved for future extensions, except those that begin with |
09bef843 |
672 | C<^_>, which may be used by user programs and are guaranteed not to |
14218588 |
673 | acquire special meaning in any future version of Perl. |
2b92dfce |
674 | |
09bef843 |
675 | =head2 C<use attrs> implicit in subroutine attributes |
676 | |
677 | Formerly, if you wanted to mark a subroutine as being a method call or |
678 | as requiring an automatic lock() when it is entered, you had to declare |
679 | that with a C<use attrs> pragma in the body of the subroutine. |
680 | That can now be accomplished with a declaration syntax, like this: |
681 | |
0120eecf |
682 | sub mymethod : locked method ; |
09bef843 |
683 | ... |
0120eecf |
684 | sub mymethod : locked :method { |
09bef843 |
685 | ... |
686 | } |
687 | |
688 | F<AutoSplit.pm> and F<SelfLoader.pm> have been updated to keep the attributes |
689 | with the stubs they provide. See L<attributes>. |
690 | |
a5222a85 |
691 | =head2 Regular expression improvements |
692 | |
693 | change#2827,2373,2372,2365,1813,1800,4112,4158,4215,4301 |
694 | [TODO - Ilya Zakharevich <ilya@math.ohio-state.edu>] |
695 | |
696 | =head2 Overloading improvements |
697 | |
698 | change#2150 |
699 | [TODO - Ilya Zakharevich <ilya@math.ohio-state.edu>] |
700 | |
701 | =head2 open() with more than two arguments |
702 | |
703 | [TODO - Ilya Zakharevich <ilya@math.ohio-state.edu>] |
704 | |
705 | =head2 Support for interpolating named characters |
706 | |
707 | change#4052 |
708 | [TODO - Ilya Zakharevich <ilya@math.ohio-state.edu>] |
709 | |
08cd8952 |
710 | =head2 Experimental support for user-hooks in @INC |
a5222a85 |
711 | |
712 | [TODO - Ken Fox <kfox@ford.com>] |
713 | |
714 | =head2 C<require> and C<do> may be overridden |
715 | |
716 | C<require> and C<do 'file'> operations may be overridden locally |
717 | by importing subroutines of the same name into the current package |
718 | (or globally by importing them into the CORE::GLOBAL:: namespace). |
719 | Overriding C<require> will also affect C<use>, provided the override |
720 | is visible at compile-time. |
721 | See L<perlsub/"Overriding Built-in Functions">. |
722 | |
723 | =head2 New variable $^C reflects C<-c> switch |
724 | |
08cd8952 |
725 | C<$^C> has a boolean value that reflects whether perl is being run |
a5222a85 |
726 | in compile-only mode (i.e. via the C<-c> switch). Since |
727 | BEGIN blocks are executed under such conditions, this variable |
728 | enables perl code to determine whether actions that make sense |
729 | only during normal running are warranted. See L<perlvar>. |
730 | |
731 | =head2 Optional Y2K warnings |
732 | |
733 | If Perl is built with the cpp macro C<PERL_Y2KWARN> defined, |
734 | it emits optional warnings when concatenating the number 19 |
735 | with another number. |
736 | |
737 | This behavior must be specifically enabled when running Configure. |
738 | See L<INSTALL> and L<README.Y2K>. |
739 | |
fbad3eb5 |
740 | =head1 Significant bug fixes |
741 | |
742 | =head2 E<lt>HANDLEE<gt> on empty files |
743 | |
191f2cf3 |
744 | With C<$/> set to C<undef>, "slurping" an empty file returns a string of |
14218588 |
745 | zero length (instead of C<undef>, as it used to) the first time the |
191f2cf3 |
746 | HANDLE is read after C<$/> is set to C<undef>. Further reads yield |
747 | C<undef>. |
fbad3eb5 |
748 | |
749 | This means that the following will append "foo" to an empty file (it used |
14218588 |
750 | to do nothing): |
fbad3eb5 |
751 | |
752 | perl -0777 -pi -e 's/^/foo/' empty_file |
753 | |
14218588 |
754 | The behaviour of: |
fbad3eb5 |
755 | |
756 | perl -pi -e 's/^/foo/' empty_file |
757 | |
758 | is unchanged (it continues to leave the file empty). |
759 | |
0244c3a4 |
760 | =head2 C<eval '...'> improvements |
761 | |
762 | Line numbers (as reflected by caller() and most diagnostics) within |
763 | C<eval '...'> were often incorrect when here documents were involved. |
764 | This has been corrected. |
765 | |
766 | Lexical lookups for variables appearing in C<eval '...'> within |
767 | functions that were themselves called within an C<eval '...'> were |
14218588 |
768 | searching the wrong place for lexicals. The lexical search now |
769 | correctly ends at the subroutine's block boundary. |
0244c3a4 |
770 | |
771 | Parsing of here documents used to be flawed when they appeared as |
772 | the replacement expression in C<eval 's/.../.../e'>. This has |
773 | been fixed. |
774 | |
a5222a85 |
775 | =head2 All compilation errors are true errors |
776 | |
777 | Some "errors" encountered at compile time were by neccessity |
778 | generated as warnings followed by eventual termination of the |
779 | program. This enabled more such errors to be reported in a |
780 | single run, rather than causing a hard stop at the first error |
781 | that was encountered. |
782 | |
783 | The mechanism for reporting such errors has been reimplemented |
784 | to queue compile-time errors and report them at the end of the |
785 | compilation as true errors rather than as warnings. This fixes |
08cd8952 |
786 | cases where error messages leaked through in the form of warnings |
787 | when code was compiled at run time using C<eval STRING>, and |
788 | also allows such errors to be reliably trapped using __DIE__ hooks. |
a5222a85 |
789 | |
45bc9206 |
790 | =head2 Automatic flushing of output buffers |
791 | |
14218588 |
792 | fork(), exec(), system(), qx//, and pipe open()s now flush buffers |
793 | of all files opened for output when the operation |
794 | was attempted. This mostly eliminates confusing |
45bc9206 |
795 | buffering mishaps suffered by users unaware of how Perl internally |
14218588 |
796 | handles I/O. |
45bc9206 |
797 | |
af8c498a |
798 | =head2 Better diagnostics on meaningless filehandle operations |
799 | |
800 | Constructs such as C<open(E<lt>FHE<gt>)> and C<close(E<lt>FHE<gt>)> |
801 | are compile time errors. Attempting to read from filehandles that |
802 | were opened only for writing will now produce warnings (just as |
803 | writing to read-only filehandles does). |
804 | |
a5222a85 |
805 | =head2 Where possible, buffered data discarded from duped input filehandle |
806 | |
807 | C<open(NEW, "E<lt>&OLD")> now attempts to discard any data that |
808 | was previously read and buffered in C<OLD> before duping the handle. |
809 | On platforms where doing this is allowed, the next read operation |
810 | on C<NEW> will return the same data as the corresponding operation |
811 | on C<OLD>. Formerly, it would have returned the data from the start |
812 | of the following disk block instead. |
813 | |
820475bd |
814 | =head2 eof() has the same old magic as <> |
815 | |
816 | C<eof()> would return true if no attempt to read from C<E<lt>E<gt>> had |
817 | yet been made. C<eof()> has been changed to have a little magic of its |
818 | own, it now opens the C<E<lt>E<gt>> files. |
819 | |
a5222a85 |
820 | =head2 system(), backticks and pipe open now reflect exec() failure |
821 | |
822 | On Unix and similar platforms, system(), qx() and open(FOO, "cmd |") |
823 | etc., are implemented via fork() and exec(). When the underlying |
824 | exec() fails, earlier versions did not report the error properly, |
825 | since the exec() happened to be in a different process. |
826 | |
827 | The child process now communicates with the parent about the |
437784d6 |
828 | error in launching the external command, which allows these |
a5222a85 |
829 | constructs to return with their usual error value and set $!. |
830 | |
831 | =head2 Implicitly closed filehandles are safer |
832 | |
833 | Sometimes implicitly closed filehandles (as when they are localized, |
834 | and Perl automatically closes them on exiting the scope) could |
835 | inadvertently set $? or $!. This has been corrected. |
836 | |
837 | =head2 C<(\$)> prototype and C<$foo{a}> |
838 | |
839 | An scalar reference prototype now correctly allows a hash or |
840 | array element in that slot. |
841 | |
842 | =head2 Pseudo-hashes work better |
843 | |
844 | Dereferencing some types of reference values in a pseudo-hash, |
845 | such as C<$ph->{foo}[1]>, was accidentally disallowed. This has |
846 | been corrected. |
847 | |
848 | When applied to a pseudo-hash element, exists() now reports whether |
849 | the specified value exists, not merely if the key is valid. |
850 | |
01020589 |
851 | delete() now works on pseudo-hashes. When given a pseudo-hash element |
852 | or slice it deletes the values corresponding to the keys (but not the keys |
853 | themselves). See L<perlref/"Pseudo-hashes: Using an array as a hash">. |
854 | |
a5222a85 |
855 | =head2 C<goto &sub> and AUTOLOAD |
856 | |
08cd8952 |
857 | The C<goto &sub> construct works correctly when C<&sub> happens |
a5222a85 |
858 | to be autoloaded. |
859 | |
860 | =head2 C<-bareword> allowed under C<use integer> |
861 | |
862 | The autoquoting of barewords preceded by C<-> did not work |
863 | in prior versions when the C<integer> pragma was enabled. |
864 | This has been fixed. |
865 | |
866 | =head2 Boolean assignment operators are legal lvalues |
867 | |
868 | Constructs such as C<($a ||= 2) += 1> are now allowed. |
869 | |
870 | =head2 C<sort $coderef @foo> allowed |
871 | |
872 | sort() did not accept a subroutine reference as the comparison |
08cd8952 |
873 | function in earlier versions. This is now permitted. |
a5222a85 |
874 | |
875 | =head2 Failures in DESTROY() |
876 | |
877 | When code in a destructor threw an exception, it went unnoticed |
878 | in earlier versions of Perl, unless someone happened to be |
879 | looking in $@ just after the point the destructor happened to |
880 | run. Such failures are now visible as warnings when warnings are |
881 | enabled. |
882 | |
883 | =head2 Locale bugs fixed |
54195c32 |
884 | |
437784d6 |
885 | printf() and sprintf() previously reset the numeric locale |
67d3893f |
886 | back to the default "C" locale. This has been fixed. |
887 | |
888 | Numbers formatted according to the local numeric locale |
889 | (such as using a decimal comma instead of a decimal dot) caused |
890 | "isn't numeric" warnings, even while the operations accessing |
891 | those numbers produced correct results. The warnings are gone. |
54195c32 |
892 | |
a5222a85 |
893 | =head2 Memory leaks |
894 | |
895 | The C<eval 'return sub {...}'> construct could sometimes leak |
896 | memory. This has been fixed. |
897 | |
898 | Operations that aren't filehandle constructors used to leak memory |
899 | when used on invalid filehandles. This has been fixed. |
900 | |
901 | Constructs that modified C<@_> could fail to deallocate values |
902 | in C<@_> and thus leak memory. This has been corrected. |
903 | |
904 | =head2 Spurious subroutine stubs after failed subroutine calls |
905 | |
906 | Perl could sometimes create empty subroutine stubs when a |
907 | subroutine was not found in the package. Such cases stopped |
908 | later method lookups from progressing into base packages. |
909 | This has been corrected. |
910 | |
911 | =head2 Consistent numeric conversions |
912 | |
913 | change#3378,3318 |
914 | [TODO - Ilya Zakharevich <ilya@math.ohio-state.edu>] |
915 | |
916 | =head2 Taint failures under C<-U> |
917 | |
918 | When running in unsafe mode, taint violations could sometimes |
919 | cause silent failures. This has been fixed. |
920 | |
921 | =head2 END blocks and the C<-c> switch |
922 | |
923 | Prior versions used to run BEGIN B<and> END blocks when Perl was |
924 | run in compile-only mode. Since this is typically not the expected |
08cd8952 |
925 | behavior, END blocks are not executed anymore when the C<-c> switch |
a5222a85 |
926 | is used. |
927 | |
7d30b5c4 |
928 | See L<CHECK blocks> for how to run things when the compile phase ends. |
a5222a85 |
929 | |
930 | =head2 Potential to leak DATA filehandles |
931 | |
932 | Using the C<__DATA__> token creates an implicit filehandle to |
933 | the file that contains the token. It is the program's |
934 | responsibility to close it when it is done reading from it. |
935 | |
936 | This caveat is now better explained in the documentation. |
937 | See L<perldata>. |
938 | |
939 | =head2 Diagnostics follow STDERR |
940 | |
941 | Diagnostic output now goes to whichever file the C<STDERR> handle |
942 | is pointing at, instead of always going to the underlying C runtime |
943 | library's C<stderr>. |
944 | |
945 | =head2 Other fixes for better diagnostics |
946 | |
437784d6 |
947 | Line numbers are no longer suppressed (under most likely circumstances) |
a5222a85 |
948 | during the global destruction phase. |
949 | |
950 | Diagnostics emitted from code running in threads other than the main |
951 | thread are now accompanied by the thread ID. |
952 | |
953 | Embedded null characters in diagnostics now actually show up. They |
954 | used to truncate the message in prior versions. |
955 | |
956 | $foo::a and $foo::b are now exempt from "possible typo" warnings only |
957 | if sort() is encountered in package foo. |
958 | |
501fbaef |
959 | Unrecognized alphabetic escapes encountered when parsing quote |
a5222a85 |
960 | constructs now generate a warning, since they may take on new |
961 | semantics in later versions of Perl. |
962 | |
963 | =head1 Performance enhancements |
964 | |
965 | =head2 Simple sort() using { $a <=> $b } and the like are optimized |
966 | |
08cd8952 |
967 | Many common sort() operations using a simple inlined block are now |
a5222a85 |
968 | optimized for faster performance. |
969 | |
970 | =head2 Optimized assignments to lexical variables |
971 | |
972 | Certain operations in the RHS of assignment statements have been |
973 | optimized to directly set the lexical variable on the LHS, |
974 | eliminating redundant copying overheads. |
975 | |
976 | =head2 Method lookups optimized |
977 | |
978 | [TODO - Chip Salzenberg <chip@perlsupport.com>] |
979 | |
980 | =head2 Faster mechanism to invoke XSUBs |
981 | |
982 | change#4044,4125 |
983 | [TODO - Ilya Zakharevich <ilya@math.ohio-state.edu>] |
984 | |
985 | =head2 Perl_malloc() improvements |
986 | |
987 | change#4237 |
988 | [TODO - Ilya Zakharevich <ilya@math.ohio-state.edu>] |
989 | |
990 | =head2 Faster subroutine calls |
991 | |
992 | Minor changes in how subroutine calls are handled internally |
993 | provide marginal improvements in performance. |
994 | |
995 | =head1 Platform specific changes |
996 | |
997 | =head2 Additional supported platforms |
ba8251e8 |
998 | |
5fdc711f |
999 | =over 4 |
1000 | |
1001 | =item * |
1002 | |
6c67e1bb |
1003 | VM/ESA is now supported. |
1004 | |
5fdc711f |
1005 | =item * |
1006 | |
ee3907e2 |
1007 | Siemens BS2000 is now supported under the POSIX Shell. |
1008 | |
1009 | =item * |
1010 | |
2bb14304 |
1011 | The Mach CThreads (NEXTSTEP, OPENSTEP) are now supported by the Thread |
1012 | extension. |
6c67e1bb |
1013 | |
5fdc711f |
1014 | =item * |
1015 | |
ee3907e2 |
1016 | GNU/Hurd is now supported. |
6c67e1bb |
1017 | |
00ad96e1 |
1018 | =item * |
1019 | |
1020 | Rhapsody is now supported. |
1021 | |
27806c82 |
1022 | =item * |
1023 | |
1024 | EPOC is is now supported (on Psion 5). |
1025 | |
5fdc711f |
1026 | =back |
1027 | |
a5222a85 |
1028 | =head2 DOS |
1029 | |
d524f05e |
1030 | =over 4 |
1031 | |
1032 | =item * |
1033 | |
1034 | Perl now works with djgpp 2.02 (and 2.03 alpha). |
1035 | |
1036 | =item * |
1037 | |
1038 | Environment variable names are not converted to uppercase any more. |
1039 | |
1040 | =item * |
1041 | |
1042 | Wrong exit code from backticks now fixed. |
1043 | |
1044 | =item * |
1045 | |
1046 | This port is still using its own builtin globbing. |
1047 | |
1048 | =back |
a5222a85 |
1049 | |
1050 | =head2 OS/2 |
1051 | |
1052 | [TODO - Ilya Zakharevich <ilya@math.ohio-state.edu>] |
1053 | |
1054 | =head2 VMS |
1055 | |
1056 | [TODO - Charles Bailey <bailey@newman.upenn.edu>] |
1057 | |
1058 | =head2 Win32 |
1059 | |
1060 | Site library searches failed to look for ".../site/5.XXX/lib" |
1061 | if ".../site/5.XXXYY/lib" wasn't found. This has been corrected. |
1062 | |
1063 | When given a pathname that consists only of a drivename, such |
1064 | as C<A:>, opendir() and stat() now use the current working |
1065 | directory for the drive rather than the drive root. |
1066 | |
1067 | The builtin XSUB functions in the Win32:: namespace are |
1068 | documented. See L<Win32>. |
1069 | |
1070 | $^X now contains the full path name of the running executable. |
1071 | |
1072 | A Win32::GetLongPathName() function is provided to complement |
1073 | Win32::GetFullPathName() and Win32::GetShortPathName(). See L<Win32>. |
1074 | |
1075 | POSIX::uname() is supported. |
1076 | |
1077 | system(1,...) now returns true process IDs rather than process |
1078 | handles. kill() accepts any real process id, rather than strictly |
1079 | return values from system(1,...). |
1080 | |
1081 | The C<Shell> module is supported. |
1082 | |
883d36a6 |
1083 | Rudimentary support for building under command.com in Windows 95 |
1084 | has been added. |
1085 | |
c39cd008 |
1086 | Scripts are read in binary mode by default to allow ByteLoader (and |
1087 | the filter mechanism in general) to work properly. For compatibility, |
53129d29 |
1088 | the DATA filehandle will be set to text mode if a carriage return is |
1089 | detected at the end of the line containing the __END__ or __DATA__ |
1090 | token; if not, the DATA filehandle will be left open in binary mode. |
1091 | Earlier versions always opened the DATA filehandle in text mode. |
c39cd008 |
1092 | |
a5222a85 |
1093 | [TODO - GSAR] |
1094 | |
6c67e1bb |
1095 | =head1 New tests |
1096 | |
1097 | =over 4 |
1098 | |
09bef843 |
1099 | =item lib/attrs |
1100 | |
1101 | Compatibility tests for C<sub : attrs> vs the older C<use attrs>. |
1102 | |
1103 | =item lib/io_const |
6c67e1bb |
1104 | |
1105 | IO constants (SEEK_*, _IO*). |
14218588 |
1106 | |
09bef843 |
1107 | =item lib/io_dir |
6c67e1bb |
1108 | |
1109 | Directory-related IO methods (new, read, close, rewind, tied delete). |
1110 | |
09bef843 |
1111 | =item lib/io_multihomed |
6c67e1bb |
1112 | |
1113 | INET sockets with multi-homed hosts. |
1114 | |
09bef843 |
1115 | =item lib/io_poll |
6c67e1bb |
1116 | |
1117 | IO poll(). |
1118 | |
09bef843 |
1119 | =item lib/io_unix |
6c67e1bb |
1120 | |
1121 | UNIX sockets. |
1122 | |
09bef843 |
1123 | =item op/attrs |
1124 | |
1125 | Regression tests for C<my ($x,@y,%z) : attrs> and <sub : attrs>. |
1126 | |
6c67e1bb |
1127 | =item op/filetest |
1128 | |
1129 | File test operators. |
1130 | |
1131 | =item op/lex_assign |
1132 | |
5fdc711f |
1133 | Verify operations that access pad objects (lexicals and temporaries). |
6c67e1bb |
1134 | |
afebc493 |
1135 | =item op/exists_sub |
1136 | |
1137 | Verify C<exists &sub> operations. |
1138 | |
6c67e1bb |
1139 | =back |
e02fdbd2 |
1140 | |
ba8251e8 |
1141 | =head1 Modules and Pragmata |
1142 | |
3e8c4fa0 |
1143 | =head2 Modules |
1144 | |
b7d8191e |
1145 | =over 4 |
1146 | |
09bef843 |
1147 | =item attributes |
1148 | |
1149 | While used internally by Perl as a pragma, this module also |
1150 | provides a way to fetch subroutine and variable attributes. |
1151 | See L<attributes>. |
1152 | |
a5222a85 |
1153 | =item B |
1154 | |
501fbaef |
1155 | The Perl Compiler suite has been extensively reworked for this |
1156 | release. |
1157 | |
a5222a85 |
1158 | [TODO - Vishal Bhatia <vishal@gol.com>, |
1159 | Nick Ing-Simmons <nick@ni-s.u-net.com>] |
1160 | |
f29c64d6 |
1161 | =item ByteLoader |
1162 | |
a5222a85 |
1163 | The ByteLoader is a dedicated extension to generate and run |
f29c64d6 |
1164 | Perl bytecode. See L<ByteLoader>. |
1165 | |
a5222a85 |
1166 | =item constant |
1167 | |
83763826 |
1168 | References can now be used. |
1169 | |
1170 | The new version also allows a leading underscore in constant names, but |
1171 | disallows a double leading underscore (as in "__LINE__"). Some other names |
1172 | are disallowed or warned against, including BEGIN, END, etc. Some names |
1173 | which were forced into main:: used to fail silently in some cases; now they're |
1174 | fatal (outside of main::) and an optional warning (inside of main::). |
1175 | The ability to detect whether a constant had been set with a given name has |
1176 | been added. |
1177 | |
1178 | See L<constant>. |
a5222a85 |
1179 | |
1180 | =item charnames |
1181 | |
1182 | change#4052 |
1183 | [TODO - Ilya Zakharevich <ilya@math.ohio-state.edu>] |
1184 | |
1185 | =item Data::Dumper |
1186 | |
1187 | A C<Maxdepth> setting can be specified to avoid venturing |
73b437c8 |
1188 | too deeply into deep data structures. See L<Data::Dumper>. |
a5222a85 |
1189 | |
1190 | Dumping C<qr//> objects works correctly. |
1191 | |
1192 | =item DB |
1193 | |
1194 | C<DB> is an experimental module that exposes a clean abstraction |
1195 | to Perl's debugging API. |
1196 | |
1197 | =item DB_File |
1198 | |
0536e0eb |
1199 | DB_File can now be built with Berkeley DB versions 1, 2 or 3. |
1200 | See C<ext/DB_File/Changes>. |
a5222a85 |
1201 | |
f29c64d6 |
1202 | =item Devel::DProf |
1203 | |
9e107c59 |
1204 | Devel::DProf, a Perl source code profiler has been added. See |
1205 | L<Devel::DProf> and L<dprofpp>. |
f29c64d6 |
1206 | |
b7d8191e |
1207 | =item Dumpvalue |
1208 | |
437784d6 |
1209 | The Dumpvalue module provides screen dumps of Perl data. |
b7d8191e |
1210 | |
1211 | =item Benchmark |
1212 | |
54e82ce5 |
1213 | Overall, Benchmark results exhibit lower average error and better timing |
1214 | accuracy. |
1215 | |
868cb350 |
1216 | You can now run tests for I<n> seconds instead of guessing the right |
14218588 |
1217 | number of tests to run: e.g. timethese(-5, ...) will run each |
1218 | code for at least 5 CPU seconds. Zero as the "number of repetitions" |
155776c0 |
1219 | means "for at least 3 CPU seconds". The output format has also |
14218588 |
1220 | changed. For example: |
155776c0 |
1221 | |
54e82ce5 |
1222 | use Benchmark;$x=3;timethese(-5,{a=>sub{$x*$x},b=>sub{$x**2}}) |
155776c0 |
1223 | |
1224 | will now output something like this: |
1225 | |
54e82ce5 |
1226 | Benchmark: running a, b, each for at least 5 CPU seconds... |
1227 | a: 5 wallclock secs ( 5.77 usr + 0.00 sys = 5.77 CPU) @ 200551.91/s (n=1156516) |
1228 | b: 4 wallclock secs ( 5.00 usr + 0.02 sys = 5.02 CPU) @ 159605.18/s (n=800686) |
155776c0 |
1229 | |
1230 | New features: "each for at least N CPU seconds...", "wallclock secs", |
1231 | and the "@ operations/CPU second (n=operations)". |
b7d8191e |
1232 | |
54e82ce5 |
1233 | timethese() now returns a reference to a hash of Benchmark objects containing |
1234 | the test results, keyed on the names of the tests. |
1235 | |
1236 | timethis() now returns the iterations field in the Benchmark result object |
1237 | instead of 0. |
1238 | |
1239 | timethese(), timethis(), and the new cmpthese() (see below) can also take |
1240 | a format specifier of 'none' to suppress output. |
1241 | |
1242 | A new function countit() is just like timeit() except that it takes a |
1243 | TIME instead of a COUNT. |
1244 | |
1245 | A new function cmpthese() prints a chart comparing the results of each test |
1246 | returned from a timethese() call. For each possible pair of tests, the |
1247 | percentage speed difference (iters/sec or seconds/iter) is shown. |
1248 | |
1249 | For other details, see L<Benchmark>. |
a5222a85 |
1250 | |
f505c983 |
1251 | =item Devel::Peek |
1252 | |
1253 | The Devel::Peek module provides access to the internal representation |
14218588 |
1254 | of Perl variables and data. It is a data debugging tool for the XS programmer. |
f505c983 |
1255 | |
a5222a85 |
1256 | =item ExtUtils::MakeMaker |
1257 | |
1258 | change#4135, also needs docs in module pod |
1259 | [TODO - Ilya Zakharevich <ilya@math.ohio-state.edu>] |
1260 | |
b7d8191e |
1261 | =item Fcntl |
1262 | |
1263 | More Fcntl constants added: F_SETLK64, F_SETLKW64, O_LARGEFILE for |
822ba51d |
1264 | large file (more than 4GB) access Note that the O_LARGEFILE is |
1265 | automatically/transparently added to sysopen() flags if large file |
1266 | support has been configured), Free/Net/OpenBSD locking behaviour flags |
1267 | F_FLOCK, F_POSIX, Linux F_SHLCK, and O_ACCMODE: the combined mask of |
1268 | O_RDONLY, O_WRONLY, and O_RDWR. Also SEEK_SET, SEEK_CUR, and SEEK_END |
1269 | added for one-stop shopping of the seek/sysseek constants. |
b7d8191e |
1270 | |
a5222a85 |
1271 | =item File::Compare |
1272 | |
1273 | A compare_text() function has been added, which allows custom |
1274 | comparison functions. See L<File::Compare>. |
1275 | |
1276 | =item File::Find |
1277 | |
1278 | File::Find now works correctly when the wanted() function is either |
1279 | autoloaded or is a symbolic reference. |
1280 | |
08cd8952 |
1281 | A bug that caused File::Find to lose track of the working directory |
a5222a85 |
1282 | when pruning top-level directories has been fixed. |
1283 | |
81793b90 |
1284 | File::Find now also supports several other options to control its |
1285 | behavior. It can follow symbolic links if the C<follow> option is |
1286 | specified. Enabling the C<no_chdir> option will make File::Find skip |
1287 | changing the current directory when walking directories. The C<untaint> |
1288 | flag can be useful when running with taint checks enabled. |
1289 | |
1290 | See L<File::Find>. |
1291 | |
becf2bd3 |
1292 | =item File::Glob |
1293 | |
52bb0670 |
1294 | This extension implements BSD-style file globbing. By default, |
1295 | it will also be used for the internal implementation of the glob() |
1296 | operator. See L<File::Glob>. |
becf2bd3 |
1297 | |
f505c983 |
1298 | =item File::Spec |
1299 | |
1300 | New methods have been added to the File::Spec module: devnull() returns |
19799a22 |
1301 | the name of the null device (/dev/null on Unix) and tmpdir() the name of |
14218588 |
1302 | the temp directory (normally /tmp on Unix). There are now also methods |
f505c983 |
1303 | to convert between absolute and relative filenames: abs2rel() and |
14218588 |
1304 | rel2abs(). For compatibility with operating systems that specify volume |
1305 | names in file paths, the splitpath(), splitdir(), and catdir() methods |
f505c983 |
1306 | have been added. |
1307 | |
1308 | =item File::Spec::Functions |
1309 | |
1310 | The new File::Spec::Functions modules provides a function interface |
14218588 |
1311 | to the File::Spec module. Allows shorthand |
f505c983 |
1312 | |
14218588 |
1313 | $fullname = catfile($dir1, $dir2, $file); |
f505c983 |
1314 | |
1315 | instead of |
1316 | |
14218588 |
1317 | $fullname = File::Spec->catfile($dir1, $dir2, $file); |
f505c983 |
1318 | |
a5222a85 |
1319 | =item Getopt::Long |
1320 | |
c6edd1b7 |
1321 | Getopt::Long licensing has changed to allow the Perl Artistic License |
1322 | as well as the GPL. It used to be GPL only, which got in the way of |
1323 | non-GPL applications that wanted to use Getopt::Long. |
1324 | |
1325 | Getopt::Long encourages the use of Pod::Usage to produce help |
1326 | messages. For example: |
1327 | |
1328 | use Getopt::Long; |
1329 | use Pod::Usage; |
1330 | my $man = 0; |
1331 | my $help = 0; |
1332 | GetOptions('help|?' => \$help, man => \$man) or pod2usage(2); |
1333 | pod2usage(1) if $help; |
1334 | pod2usage(-exitstatus => 0, -verbose => 2) if $man; |
1335 | |
1336 | __END__ |
1337 | |
1338 | =head1 NAME |
1339 | |
1340 | sample - Using GetOpt::Long and Pod::Usage |
1341 | |
1342 | =head1 SYNOPSIS |
1343 | |
1344 | sample [options] [file ...] |
1345 | |
1346 | Options: |
1347 | -help brief help message |
1348 | -man full documentation |
1349 | |
1350 | =head1 OPTIONS |
1351 | |
1352 | =over 8 |
1353 | |
1354 | =item B<-help> |
1355 | |
1356 | Print a brief help message and exits. |
1357 | |
1358 | =item B<-man> |
1359 | |
1360 | Prints the manual page and exits. |
1361 | |
1362 | =back |
1363 | |
1364 | =head1 DESCRIPTION |
1365 | |
1366 | B<This program> will read the given input file(s) and do someting |
1367 | useful with the contents thereof. |
1368 | |
1369 | =cut |
1370 | |
1371 | See L<Pod::Usage> for details. |
1372 | |
1373 | A bug that prevented the non-option call-back E<lt>E<gt> from being |
1374 | specified as the first argument has been fixed. |
1375 | |
1376 | To specify the characters E<lt> and E<gt> as option starters, use |
1377 | E<gt>E<lt>. Note, however, that changing option starters is strongly |
1378 | deprecated. |
a5222a85 |
1379 | |
1380 | =item IO |
1381 | |
1382 | write() and syswrite() will now accept a single-argument |
1383 | form of the call, for consistency with Perl's syswrite(). |
1384 | |
1385 | You can now create a TCP-based IO::Socket::INET without forcing |
1386 | a connect attempt. This allows you to configure its options |
1387 | (like making it non-blocking) and then call connect() manually. |
1388 | |
1389 | A bug that prevented the IO::Socket::protocol() accessor |
1390 | from ever returning the correct value has been corrected. |
1391 | |
1392 | =item JPL |
1393 | |
1394 | Java Perl Lingo is now distributed with Perl. See jpl/README |
1395 | for more information. |
1396 | |
883d36a6 |
1397 | =item lib |
1398 | |
1399 | C<use lib> now weeds out any trailing duplicate entries. |
1400 | C<no lib> removes all named entries. |
1401 | |
e16b8f49 |
1402 | =item Math::BigInt |
1403 | |
437784d6 |
1404 | The bitwise operations C<E<lt>E<lt>>, C<E<gt>E<gt>>, C<&>, C<|>, |
e16b8f49 |
1405 | and C<~> are now supported on bigints. |
1406 | |
b7d8191e |
1407 | =item Math::Complex |
7711098a |
1408 | |
14218588 |
1409 | The accessor methods Re, Im, arg, abs, rho, and theta can now also |
868cb350 |
1410 | act as mutators (accessor $z->Re(), mutator $z->Re(3)). |
b7d8191e |
1411 | |
1412 | =item Math::Trig |
1413 | |
14218588 |
1414 | A little bit of radial trigonometry (cylindrical and spherical), |
1415 | radial coordinate conversions, and the great circle distance were added. |
b7d8191e |
1416 | |
a5222a85 |
1417 | =item Pod::Parser |
1418 | |
1419 | [TODO - Brad Appleton <bradapp@enteract.com>] |
1420 | |
1421 | =item Pod::Text and Pod::Man |
1422 | |
1423 | [TODO - Russ Allbery <rra@stanford.edu>] |
1424 | |
f4b9d880 |
1425 | =item SDBM_File |
1426 | |
1427 | An EXISTS method has been added to this module (and sdbm_exists() has |
1428 | been added to the underlying sdbm library), so one can now call exists |
14218588 |
1429 | on an SDBM_File tied hash and get the correct result, rather than a |
f4b9d880 |
1430 | runtime error. |
1431 | |
a5222a85 |
1432 | A bug that may have caused data loss when more than one disk block |
1433 | happens to be read from the database in a single FETCH() has been |
1434 | fixed. |
1435 | |
06ef4121 |
1436 | =item Time::Local |
1437 | |
1438 | The timelocal() and timegm() functions used to silently return bogus |
437784d6 |
1439 | results when the date fell outside the machine's integer range. They |
a5222a85 |
1440 | now consistently croak() if the date falls in an unsupported range. |
06ef4121 |
1441 | |
8fe0a5c4 |
1442 | =item Win32 |
1443 | |
1444 | The error return value in list context has been changed for all functions |
14218588 |
1445 | that return a list of values. Previously these functions returned a list |
1446 | with a single element C<undef> if an error occurred. Now these functions |
1447 | return the empty list in these situations. This applies to the following |
8fe0a5c4 |
1448 | functions: |
1449 | |
14218588 |
1450 | Win32::FsType |
1451 | Win32::GetOSVersion |
8fe0a5c4 |
1452 | |
1453 | The remaining functions are unchanged and continue to return C<undef> on |
1454 | error even in list context. |
1455 | |
1456 | The Win32::SetLastError(ERROR) function has been added as a complement |
1457 | to the Win32::GetLastError() function. |
1458 | |
1459 | The new Win32::GetFullPathName(FILENAME) returns the full absolute |
14218588 |
1460 | pathname for FILENAME in scalar context. In list context it returns |
1461 | a two-element list containing the fully qualified directory name and |
501fbaef |
1462 | the filename. See L<Win32>. |
8fe0a5c4 |
1463 | |
9fe6733a |
1464 | =item DBM Filters |
1465 | |
1466 | A new feature called "DBM Filters" has been added to all the |
14218588 |
1467 | DBM modules--DB_File, GDBM_File, NDBM_File, ODBM_File, and SDBM_File. |
1468 | DBM Filters add four new methods to each DBM module: |
9fe6733a |
1469 | |
1470 | filter_store_key |
1471 | filter_store_value |
1472 | filter_fetch_key |
1473 | filter_fetch_value |
1474 | |
14218588 |
1475 | These can be used to filter key-value pairs before the pairs are |
9fe6733a |
1476 | written to the database or just after they are read from the database. |
1477 | See L<perldbmfilter> for further information. |
1478 | |
b7d8191e |
1479 | =back |
3e8c4fa0 |
1480 | |
1481 | =head2 Pragmata |
1482 | |
437784d6 |
1483 | C<use attrs> is now obsolete, and is only provided for |
09bef843 |
1484 | backward-compatibility. It's been replaced by the C<sub : attributes> |
1485 | syntax. See L<perlsub/"Subroutine Attributes"> and L<attributes>. |
1486 | |
14218588 |
1487 | C<use utf8> to enable UTF-8 and Unicode support. |
43165c05 |
1488 | |
1489 | C<use caller 'encoding'> allows modules to inherit pragmatic attributes |
1490 | from the caller's context. C<encoding> is currently the only supported |
1491 | attribute. |
9d73390d |
1492 | |
4438c4b7 |
1493 | Lexical warnings pragma, C<use warnings;>, to control optional warnings. |
a5222a85 |
1494 | See L<perllexwarn>. |
6c67e1bb |
1495 | |
67d3893f |
1496 | C<use filetest> to control the behaviour of filetests (C<-r> C<-w> |
1497 | ...). Currently only one subpragma implemented, "use filetest |
1498 | 'access';", that uses access(2) or equivalent to check permissions |
1499 | instead of using stat(2) as usual. This matters in filesystems |
1500 | where there are ACLs (access control lists): the stat(2) might lie, |
1501 | but access(2) knows better. |
6c67e1bb |
1502 | |
ba8251e8 |
1503 | =head1 Utility Changes |
1504 | |
a5222a85 |
1505 | =head2 h2ph |
1506 | |
1507 | [TODO - Kurt Starsinic <kstar@chapin.edu>] |
1508 | |
1509 | =head2 perlcc |
1510 | |
1511 | C<perlcc> now supports the C and Bytecode backends. By default, |
1512 | it generates output from the simple C backend rather than the |
1513 | optimized C backend. |
1514 | |
1515 | Support for non-Unix platforms has been improved. |
1516 | |
1517 | =head2 h2xs |
1518 | |
1519 | change#4232 |
1520 | [TODO - Ilya Zakharevich <ilya@math.ohio-state.edu>] |
e02fdbd2 |
1521 | |
ba8251e8 |
1522 | =head1 Documentation Changes |
1523 | |
5fdc711f |
1524 | =over 4 |
1525 | |
883d36a6 |
1526 | =item perlcompile.pod |
1527 | |
1528 | An introduction to using the Perl Compiler suite. |
1529 | |
c7c04614 |
1530 | =item perlfilter.pod |
1531 | |
1532 | An introduction to writing Perl source filters. |
1533 | |
883d36a6 |
1534 | =item perlhack.pod |
1535 | |
1536 | Some guidelines for hacking the Perl source code. |
1537 | |
5fdc711f |
1538 | =item perlopentut.pod |
f8284313 |
1539 | |
5fdc711f |
1540 | A tutorial on using open() effectively. |
1541 | |
1542 | =item perlreftut.pod |
1543 | |
1544 | A tutorial that introduces the essentials of references. |
1545 | |
14218588 |
1546 | =item perltootc.pod |
1547 | |
1548 | A tutorial on managing class data for object modules. |
1549 | |
5fdc711f |
1550 | =back |
e02fdbd2 |
1551 | |
73b437c8 |
1552 | =head1 New or Changed Diagnostics |
ba8251e8 |
1553 | |
a99ba403 |
1554 | =over 4 |
1555 | |
56e90b21 |
1556 | =item "%s" variable %s masks earlier declaration in same %s |
1557 | |
1558 | (W) A "my" or "our" variable has been redeclared in the current scope or statement, |
1559 | effectively eliminating all access to the previous instance. This is almost |
1560 | always a typographical error. Note that the earlier variable will still exist |
1561 | until the end of the scope or until all closure referents to it are |
1562 | destroyed. |
1563 | |
33633739 |
1564 | =item "my sub" not yet implemented |
1565 | |
1566 | (F) Lexically scoped subroutines are not yet implemented. Don't try that |
1567 | yet. |
1568 | |
1569 | =item "our" variable %s redeclared |
1570 | |
1571 | (W) You seem to have already declared the same global once before in the |
1572 | current lexical scope. |
1573 | |
a99ba403 |
1574 | =item '!' allowed only after types %s |
1575 | |
1576 | (F) The '!' is allowed in pack() and unpack() only after certain types. |
1577 | See L<perlfunc/pack>. |
1578 | |
1579 | =item / cannot take a count |
1580 | |
1581 | (F) You had an unpack template indicating a counted-length string, |
1582 | but you have also specified an explicit size for the string. |
1583 | See L<perlfunc/pack>. |
1584 | |
1585 | =item / must be followed by a, A or Z |
1586 | |
1587 | (F) You had an unpack template indicating a counted-length string, |
1588 | which must be followed by one of the letters a, A or Z |
1589 | to indicate what sort of string is to be unpacked. |
1590 | See L<perlfunc/pack>. |
1591 | |
1592 | =item / must be followed by a*, A* or Z* |
1593 | |
437784d6 |
1594 | (F) You had a pack template indicating a counted-length string, |
a99ba403 |
1595 | Currently the only things that can have their length counted are a*, A* or Z*. |
1596 | See L<perlfunc/pack>. |
1597 | |
1598 | =item / must follow a numeric type |
1599 | |
1600 | (F) You had an unpack template that contained a '#', |
1601 | but this did not follow some numeric unpack specification. |
1602 | See L<perlfunc/pack>. |
1603 | |
a99ba403 |
1604 | =item /%s/: Unrecognized escape \\%c passed through |
1605 | |
1606 | (W) You used a backslash-character combination which is not recognized |
1607 | by Perl. This combination appears in an interpolated variable or a |
1028017a |
1608 | C<'>-delimited regular expression. The character was understood literally. |
1609 | |
1610 | =item /%s/: Unrecognized escape \\%c in character class passed through |
1611 | |
1612 | (W) You used a backslash-character combination which is not recognized |
1613 | by Perl inside character classes. The character was understood literally. |
a99ba403 |
1614 | |
1615 | =item /%s/ should probably be written as "%s" |
1616 | |
1617 | (W) You have used a pattern where Perl expected to find a string, |
437784d6 |
1618 | as in the first argument to C<join>. Perl will treat the true |
a99ba403 |
1619 | or false result of matching the pattern against $_ as the string, |
1620 | which is probably not what you had in mind. |
1621 | |
1622 | =item %s() called too early to check prototype |
1623 | |
1624 | (W) You've called a function that has a prototype before the parser saw a |
1625 | definition or declaration for it, and Perl could not check that the call |
1626 | conforms to the prototype. You need to either add an early prototype |
1627 | declaration for the subroutine in question, or move the subroutine |
1628 | definition ahead of the call to get proper prototype checking. Alternatively, |
1629 | if you are certain that you're calling the function correctly, you may put |
1630 | an ampersand before the name to avoid the warning. See L<perlsub>. |
1631 | |
56e90b21 |
1632 | =item %s argument is not a HASH or ARRAY element |
1633 | |
1634 | (F) The argument to exists() must be a hash or array element, such as: |
1635 | |
1636 | $foo{$bar} |
1637 | $ref->[12]->["susie"] |
1638 | |
1639 | =item %s argument is not a HASH or ARRAY element or slice |
1640 | |
1641 | (F) The argument to delete() must be either a hash or array element, such as: |
1642 | |
1643 | $foo{$bar} |
1644 | $ref->[12]->["susie"] |
1645 | |
1646 | or a hash or array slice, such as: |
1647 | |
1648 | @foo[$bar, $baz, $xyzzy] |
1649 | @{$ref->[12]}{"susie", "queue"} |
1650 | |
afebc493 |
1651 | =item %s argument is not a subroutine name |
1652 | |
1653 | (F) The argument to exists() for C<exists &sub> must be a subroutine |
1654 | name, and not a subroutine call. C<exists &sub()> will generate this error. |
1655 | |
09bef843 |
1656 | =item %s package attribute may clash with future reserved word: %s |
1657 | |
1658 | (W) A lowercase attribute name was used that had a package-specific handler. |
1659 | That name might have a meaning to Perl itself some day, even though it |
1660 | doesn't yet. Perhaps you should use a mixed-case attribute name, instead. |
1661 | See L<attributes>. |
1662 | |
a99ba403 |
1663 | =item (in cleanup) %s |
6b121555 |
1664 | |
a99ba403 |
1665 | (W) This prefix usually indicates that a DESTROY() method raised |
1666 | the indicated exception. Since destructors are usually called by |
1667 | the system at arbitrary points during execution, and often a vast |
1668 | number of times, the warning is issued only once for any number |
1669 | of failures that would otherwise result in the same message being |
1670 | repeated. |
1671 | |
1672 | Failure of user callbacks dispatched using the C<G_KEEPERR> flag |
1673 | could also result in this warning. See L<perlcall/G_KEEPERR>. |
1674 | |
1675 | =item <> should be quotes |
1676 | |
1677 | (F) You wrote C<require E<lt>fileE<gt>> when you should have written |
1678 | C<require 'file'>. |
1679 | |
1680 | =item Attempt to join self |
1681 | |
1682 | (F) You tried to join a thread from within itself, which is an |
1683 | impossible task. You may be joining the wrong thread, or you may |
1684 | need to move the join() to some other thread. |
1685 | |
1686 | =item Bad evalled substitution pattern |
1687 | |
1688 | (F) You've used the /e switch to evaluate the replacement for a |
1689 | substitution, but perl found a syntax error in the code to evaluate, |
1690 | most likely an unexpected right brace '}'. |
1691 | |
1692 | =item Bad realloc() ignored |
1693 | |
1694 | (S) An internal routine called realloc() on something that had never been |
1695 | malloc()ed in the first place. Mandatory, but can be disabled by |
1696 | setting environment variable C<PERL_BADFREE> to 1. |
1697 | |
1698 | =item Binary number > 0b11111111111111111111111111111111 non-portable |
1699 | |
1700 | (W) The binary number you specified is larger than 2**32-1 |
1701 | (4294967295) and therefore non-portable between systems. See |
1702 | L<perlport> for more on portability concerns. |
1703 | |
1704 | =item Bit vector size > 32 non-portable |
1705 | |
1706 | (W) Using bit vector sizes larger than 32 is non-portable. |
1707 | |
1708 | =item Buffer overflow in prime_env_iter: %s |
1709 | |
1710 | (W) A warning peculiar to VMS. While Perl was preparing to iterate over |
1711 | %ENV, it encountered a logical name or symbol definition which was too long, |
1712 | so it was truncated to the string shown. |
1713 | |
1714 | =item Can't check filesystem of script "%s" |
1715 | |
1716 | (P) For some reason you can't check the filesystem of the script for nosuid. |
1717 | |
56e90b21 |
1718 | =item Can't declare class for non-scalar %s in "%s" |
1719 | |
1720 | (S) Currently, only scalar variables can declared with a specific class |
1721 | qualifier in a "my" or "our" declaration. The semantics may be extended |
1722 | for other types of variables in future. |
1723 | |
1724 | =item Can't declare %s in "%s" |
1725 | |
1726 | (F) Only scalar, array, and hash variables may be declared as "my" or |
1727 | "our" variables. They must have ordinary identifiers as names. |
1728 | |
0b5b802d |
1729 | =item Can't ignore signal CHLD, forcing to default |
1730 | |
1731 | (W) Perl has detected that it is being run with the SIGCHLD signal |
1732 | (sometimes known as SIGCLD) disabled. Since disabling this signal |
1733 | will interfere with proper determination of exit status of child |
1734 | processes, Perl has reset the signal to its default value. |
1735 | This situation typically indicates that the parent program under |
1736 | which Perl may be running (e.g. cron) is being very careless. |
1737 | |
a99ba403 |
1738 | =item Can't modify non-lvalue subroutine call |
1739 | |
437784d6 |
1740 | (F) Subroutines meant to be used in lvalue context should be declared as |
1741 | such, see L<perlsub/"Lvalue subroutines">. |
a99ba403 |
1742 | |
1743 | =item Can't read CRTL environ |
1744 | |
1745 | (S) A warning peculiar to VMS. Perl tried to read an element of %ENV |
1746 | from the CRTL's internal environment array and discovered the array was |
1747 | missing. You need to figure out where your CRTL misplaced its environ |
1748 | or define F<PERL_ENV_TABLES> (see L<perlvms>) so that environ is not searched. |
1749 | |
1750 | =item Can't remove %s: %s, skipping file |
1751 | |
1752 | (S) You requested an inplace edit without creating a backup file. Perl |
1753 | was unable to remove the original file to replace it with the modified |
1754 | file. The file was left unmodified. |
1755 | |
1756 | =item Can't return %s from lvalue subroutine |
1757 | |
1758 | (F) Perl detected an attempt to return illegal lvalues (such |
1759 | as temporary or readonly values) from a subroutine used as an lvalue. |
1760 | This is not allowed. |
1761 | |
1762 | =item Can't weaken a nonreference |
1763 | |
1764 | (F) You attempted to weaken something that was not a reference. Only |
1765 | references can be weakened. |
1766 | |
1767 | =item Character class [:%s:] unknown |
1768 | |
1769 | (F) The class in the character class [: :] syntax is unknown. |
437784d6 |
1770 | See L<perlre>. |
a99ba403 |
1771 | |
1772 | =item Character class syntax [%s] belongs inside character classes |
1773 | |
1774 | (W) The character class constructs [: :], [= =], and [. .] go |
1775 | I<inside> character classes, the [] are part of the construct, |
437784d6 |
1776 | for example: /[012[:alpha:]345]/. Note that [= =] and [. .] |
1777 | are not currently implemented; they are simply placeholders for |
1778 | future extensions. |
a99ba403 |
1779 | |
1780 | =item Constant is not %s reference |
1781 | |
1782 | (F) A constant value (perhaps declared using the C<use constant> pragma) |
1783 | is being dereferenced, but it amounts to the wrong type of reference. The |
1784 | message indicates the type of reference that was expected. This usually |
1785 | indicates a syntax error in dereferencing the constant value. |
1786 | See L<perlsub/"Constant Functions"> and L<constant>. |
1787 | |
1788 | =item constant(%s): %%^H is not localized |
1789 | |
1790 | (F) When setting compile-time-lexicalized hash %^H one should set the |
1791 | corresponding bit of $^H as well. |
1792 | |
1793 | =item constant(%s): %s |
1794 | |
1795 | (F) Compile-time-substitutions (such as overloaded constants and |
1796 | character names) were not correctly set up. |
1797 | |
1798 | =item defined(@array) is deprecated |
1799 | |
1800 | (D) defined() is not usually useful on arrays because it checks for an |
1801 | undefined I<scalar> value. If you want to see if the array is empty, |
1802 | just use C<if (@array) { # not empty }> for example. |
1803 | |
1804 | =item defined(%hash) is deprecated |
1805 | |
1806 | (D) defined() is not usually useful on hashes because it checks for an |
1807 | undefined I<scalar> value. If you want to see if the hash is empty, |
1808 | just use C<if (%hash) { # not empty }> for example. |
1809 | |
1810 | =item Did not produce a valid header |
1811 | |
1812 | See Server error. |
1813 | |
33633739 |
1814 | =item Did you mean "local" instead of "our"? |
1815 | |
1816 | (W) Remember that "our" does not localize the declared global variable. |
1817 | You have declared it again in the same lexical scope, which seems superfluous. |
1818 | |
a99ba403 |
1819 | =item Document contains no data |
1820 | |
1821 | See Server error. |
1822 | |
1823 | =item entering effective %s failed |
1824 | |
1825 | (F) While under the C<use filetest> pragma, switching the real and |
1826 | effective uids or gids failed. |
6b121555 |
1827 | |
73b437c8 |
1828 | =item false [] range "%s" in regexp |
1829 | |
1830 | (W) A character class range must start and end at a literal character, not |
1831 | another character class like C<\d> or C<[:alpha:]>. The "-" in your false |
1832 | range is interpreted as a literal "-". Consider quoting the "-", "\-". |
1833 | See L<perlre>. |
1834 | |
af8c498a |
1835 | =item Filehandle %s opened only for output |
6b121555 |
1836 | |
af8c498a |
1837 | (W) You tried to read from a filehandle opened only for writing. If you |
437784d6 |
1838 | intended it to be a read/write filehandle, you needed to open it with |
af8c498a |
1839 | "+E<lt>" or "+E<gt>" or "+E<gt>E<gt>" instead of with "E<lt>" or nothing. If |
1840 | you intended only to read from the file, use "E<lt>". See |
1841 | L<perlfunc/open>. |
e02fdbd2 |
1842 | |
56e90b21 |
1843 | =item flock() on closed filehandle %s |
1844 | |
1845 | (W) The filehandle you're attempting to flock() got itself closed some |
1846 | time before now. Check your logic flow. flock() operates on filehandles. |
1847 | Are you attempting to call flock() on a dirhandle by the same name? |
1848 | |
1849 | =item Global symbol "%s" requires explicit package name |
1850 | |
1851 | (F) You've said "use strict vars", which indicates that all variables |
1852 | must either be lexically scoped (using "my"), declared beforehand using |
1853 | "our", or explicitly qualified to say which package the global variable |
1854 | is in (using "::"). |
1855 | |
a99ba403 |
1856 | =item Hexadecimal number > 0xffffffff non-portable |
1857 | |
1858 | (W) The hexadecimal number you specified is larger than 2**32-1 |
1859 | (4294967295) and therefore non-portable between systems. See |
1860 | L<perlport> for more on portability concerns. |
1861 | |
1862 | =item Ill-formed CRTL environ value "%s" |
1863 | |
1864 | (W) A warning peculiar to VMS. Perl tried to read the CRTL's internal |
1865 | environ array, and encountered an element without the C<=> delimiter |
1866 | used to spearate keys from values. The element is ignored. |
1867 | |
1868 | =item Ill-formed message in prime_env_iter: |%s| |
1869 | |
1870 | (W) A warning peculiar to VMS. Perl tried to read a logical name |
1871 | or CLI symbol definition when preparing to iterate over %ENV, and |
1872 | didn't see the expected delimiter between key and value, so the |
1873 | line was ignored. |
1874 | |
1875 | =item Illegal binary digit %s |
1876 | |
437784d6 |
1877 | (F) You used a digit other than 0 or 1 in a binary number. |
a99ba403 |
1878 | |
1879 | =item Illegal binary digit %s ignored |
1880 | |
1881 | (W) You may have tried to use a digit other than 0 or 1 in a binary number. |
1882 | Interpretation of the binary number stopped before the offending digit. |
1883 | |
1884 | =item Illegal number of bits in vec |
1885 | |
1886 | (F) The number of bits in vec() (the third argument) must be a power of |
1887 | two from 1 to 32 (or 64, if your platform supports that). |
1888 | |
1889 | =item Integer overflow in %s number |
1890 | |
1891 | (W) The hexadecimal, octal or binary number you have specified either |
c6edd1b7 |
1892 | as a literal or as an argument to hex() or oct() is too big for your |
a99ba403 |
1893 | architecture, and has been converted to a floating point number. On a |
1894 | 32-bit architecture the largest hexadecimal, octal or binary number |
1895 | representable without overflow is 0xFFFFFFFF, 037777777777, or |
1896 | 0b11111111111111111111111111111111 respectively. Note that Perl |
1897 | transparently promotes all numbers to a floating point representation |
1898 | internally--subject to loss of precision errors in subsequent |
1899 | operations. |
1900 | |
09bef843 |
1901 | =item Invalid %s attribute: %s |
1902 | |
1903 | The indicated attribute for a subroutine or variable was not recognized |
1904 | by Perl or by a user-supplied handler. See L<attributes>. |
1905 | |
1906 | =item Invalid %s attributes: %s |
1907 | |
1908 | The indicated attributes for a subroutine or variable were not recognized |
1909 | by Perl or by a user-supplied handler. See L<attributes>. |
1910 | |
73b437c8 |
1911 | =item invalid [] range "%s" in regexp |
1912 | |
1913 | The offending range is now explicitly displayed. |
1914 | |
09bef843 |
1915 | =item Invalid separator character %s in attribute list |
1916 | |
0120eecf |
1917 | (F) Something other than a colon or whitespace was seen between the |
09bef843 |
1918 | elements of an attribute list. If the previous attribute |
1919 | had a parenthesised parameter list, perhaps that list was terminated |
1920 | too soon. See L<attributes>. |
1921 | |
a99ba403 |
1922 | =item Invalid separator character %s in subroutine attribute list |
1923 | |
0120eecf |
1924 | (F) Something other than a colon or whitespace was seen between the |
a99ba403 |
1925 | elements of a subroutine attribute list. If the previous attribute |
1926 | had a parenthesised parameter list, perhaps that list was terminated |
1927 | too soon. |
1928 | |
1929 | =item leaving effective %s failed |
1930 | |
1931 | (F) While under the C<use filetest> pragma, switching the real and |
1932 | effective uids or gids failed. |
1933 | |
1934 | =item Lvalue subs returning %s not implemented yet |
1935 | |
1936 | (F) Due to limitations in the current implementation, array and hash |
1937 | values cannot be returned in subroutines used in lvalue context. |
1938 | See L<perlsub/"Lvalue subroutines">. |
1939 | |
1940 | =item Method %s not permitted |
1941 | |
1942 | See Server error. |
1943 | |
1944 | =item Missing %sbrace%s on \N{} |
1945 | |
1946 | (F) Wrong syntax of character name literal C<\N{charname}> within |
1947 | double-quotish context. |
1948 | |
06eaf0bc |
1949 | =item Missing command in piped open |
1950 | |
1951 | (W) You used the C<open(FH, "| command")> or C<open(FH, "command |")> |
1952 | construction, but the command was missing or blank. |
1953 | |
09bef843 |
1954 | =item Missing name in "my sub" |
1955 | |
1956 | (F) The reserved syntax for lexically scoped subroutines requires that they |
1957 | have a name with which they can be found. |
1958 | |
56e90b21 |
1959 | =item No %s specified for -%c |
1960 | |
1961 | (F) The indicated command line switch needs a mandatory argument, but |
1962 | you haven't specified one. |
1963 | |
1964 | =item No package name allowed for variable %s in "our" |
1965 | |
1966 | (F) Fully qualified variable names are not allowed in "our" declarations, |
1967 | because that doesn't make much sense under existing semantics. Such |
1968 | syntax is reserved for future extensions. |
1969 | |
1970 | =item No space allowed after -%c |
1971 | |
1972 | (F) The argument to the indicated command line switch must follow immediately |
1973 | after the switch, without intervening spaces. |
1974 | |
a99ba403 |
1975 | =item no UTC offset information; assuming local time is UTC |
1976 | |
1977 | (S) A warning peculiar to VMS. Perl was unable to find the local |
1978 | timezone offset, so it's assuming that local system time is equivalent |
1979 | to UTC. If it's not, define the logical name F<SYS$TIMEZONE_DIFFERENTIAL> |
1980 | to translate to the number of seconds which need to be added to UTC to |
1981 | get local time. |
1982 | |
1983 | =item Octal number > 037777777777 non-portable |
1984 | |
1985 | (W) The octal number you specified is larger than 2**32-1 (4294967295) |
1986 | and therefore non-portable between systems. See L<perlport> for more |
1987 | on portability concerns. |
1988 | |
1989 | See also L<perlport> for writing portable code. |
1990 | |
1991 | =item panic: del_backref |
1992 | |
1993 | (P) Failed an internal consistency check while trying to reset a weak |
1994 | reference. |
1995 | |
1996 | =item panic: kid popen errno read |
1997 | |
1998 | (F) forked child returned an incomprehensible message about its errno. |
1999 | |
2000 | =item panic: magic_killbackrefs |
2001 | |
2002 | (P) Failed an internal consistency check while trying to reset all weak |
2003 | references to an object. |
2004 | |
56e90b21 |
2005 | =item Parentheses missing around "%s" list |
2006 | |
2007 | (W) You said something like |
2008 | |
2009 | my $foo, $bar = @_; |
2010 | |
2011 | when you meant |
2012 | |
2013 | my ($foo, $bar) = @_; |
2014 | |
2015 | Remember that "my", "our" and "local" bind closer than comma. |
2016 | |
a99ba403 |
2017 | =item Possible Y2K bug: %s |
2018 | |
2019 | (W) You are concatenating the number 19 with another number, which |
2020 | could be a potential Year 2000 problem. |
2021 | |
2022 | =item Premature end of script headers |
2023 | |
2024 | See Server error. |
2025 | |
0b5b802d |
2026 | =item Repeat count in pack overflows |
2027 | |
2028 | (F) You can't specify a repeat count so large that it overflows |
2029 | your signed integers. See L<perlfunc/pack>. |
2030 | |
2031 | =item Repeat count in unpack overflows |
2032 | |
2033 | (F) You can't specify a repeat count so large that it overflows |
2034 | your signed integers. See L<perlfunc/unpack>. |
2035 | |
a99ba403 |
2036 | =item realloc() of freed memory ignored |
2037 | |
2038 | (S) An internal routine called realloc() on something that had already |
2039 | been freed. |
2040 | |
2041 | =item Reference is already weak |
2042 | |
2043 | (W) You have attempted to weaken a reference that is already weak. |
2044 | Doing so has no effect. |
2045 | |
2046 | =item setpgrp can't take arguments |
2047 | |
2048 | (F) Your system has the setpgrp() from BSD 4.2, which takes no arguments, |
2049 | unlike POSIX setpgid(), which takes a process ID and process group ID. |
2050 | |
2051 | =item Strange *+?{} on zero-length expression |
2052 | |
2053 | (W) You applied a regular expression quantifier in a place where it |
2054 | makes no sense, such as on a zero-width assertion. |
2055 | Try putting the quantifier inside the assertion instead. For example, |
2056 | the way to match "abc" provided that it is followed by three |
2057 | repetitions of "xyz" is C</abc(?=(?:xyz){3})/>, not C</abc(?=xyz){3}/>. |
2058 | |
2059 | =item switching effective %s is not implemented |
2060 | |
2061 | (F) While under the C<use filetest> pragma, we cannot switch the |
2062 | real and effective uids or gids. |
2063 | |
437784d6 |
2064 | =item This Perl can't reset CRTL environ elements (%s) |
a99ba403 |
2065 | |
2066 | =item This Perl can't set CRTL environ elements (%s=%s) |
2067 | |
2068 | (W) Warnings peculiar to VMS. You tried to change or delete an element |
2069 | of the CRTL's internal environ array, but your copy of Perl wasn't |
2070 | built with a CRTL that contained the setenv() function. You'll need to |
2071 | rebuild Perl with a CRTL that does, or redefine F<PERL_ENV_TABLES> (see |
2072 | L<perlvms>) so that the environ array isn't the target of the change to |
2073 | %ENV which produced the warning. |
2074 | |
2075 | =item Unknown open() mode '%s' |
2076 | |
437784d6 |
2077 | (F) The second argument of 3-argument open() is not among the list |
2078 | of valid modes: C<L<lt>>, C<L<gt>>, C<E<gt>E<gt>>, C<+L<lt>>, |
2079 | C<+L<gt>>, C<+E<gt>E<gt>>, C<-|>, C<|->. |
a99ba403 |
2080 | |
2081 | =item Unknown process %x sent message to prime_env_iter: %s |
2082 | |
2083 | (P) An error peculiar to VMS. Perl was reading values for %ENV before |
2084 | iterating over it, and someone else stuck a message in the stream of |
2085 | data Perl expected. Someone's very confused, or perhaps trying to |
2086 | subvert Perl's population of %ENV for nefarious purposes. |
2087 | |
af8c498a |
2088 | =item Unrecognized escape \\%c passed through |
2089 | |
2090 | (W) You used a backslash-character combination which is not recognized |
1028017a |
2091 | by Perl. The character was understood literally. |
af8c498a |
2092 | |
09bef843 |
2093 | =item Unterminated attribute parameter in attribute list |
2094 | |
2095 | (F) The lexer saw an opening (left) parenthesis character while parsing an |
2096 | attribute list, but the matching closing (right) parenthesis |
2097 | character was not found. You may need to add (or remove) a backslash |
2098 | character to get your parentheses to balance. See L<attributes>. |
2099 | |
2100 | =item Unterminated attribute list |
2101 | |
2102 | (F) The lexer found something other than a simple identifier at the start |
2103 | of an attribute, and it wasn't a semicolon or the start of a |
2104 | block. Perhaps you terminated the parameter list of the previous attribute |
2105 | too soon. See L<attributes>. |
2106 | |
09bef843 |
2107 | =item Unterminated attribute parameter in subroutine attribute list |
2108 | |
2109 | (F) The lexer saw an opening (left) parenthesis character while parsing a |
2110 | subroutine attribute list, but the matching closing (right) parenthesis |
2111 | character was not found. You may need to add (or remove) a backslash |
2112 | character to get your parentheses to balance. |
2113 | |
2114 | =item Unterminated subroutine attribute list |
2115 | |
2116 | (F) The lexer found something other than a simple identifier at the start |
2117 | of a subroutine attribute, and it wasn't a semicolon or the start of a |
2118 | block. Perhaps you terminated the parameter list of the previous attribute |
2119 | too soon. |
2120 | |
a99ba403 |
2121 | =item Value of CLI symbol "%s" too long |
eb6e2d6f |
2122 | |
a99ba403 |
2123 | (W) A warning peculiar to VMS. Perl tried to read the value of an %ENV |
2124 | element from a CLI symbol table, and found a resultant string longer |
2125 | than 1024 characters. The return value has been truncated to 1024 |
2126 | characters. |
eb6e2d6f |
2127 | |
a99ba403 |
2128 | =item Version number must be a constant number |
ba8251e8 |
2129 | |
a99ba403 |
2130 | (P) The attempt to translate a C<use Module n.n LIST> statement into |
2131 | its equivalent C<BEGIN> block found an internal inconsistency with |
2132 | the version number. |
2133 | |
2134 | =back |
27806c82 |
2135 | |
a5222a85 |
2136 | =head1 Obsolete Diagnostics |
3175b8cd |
2137 | |
a99ba403 |
2138 | =over 4 |
2139 | |
2140 | =item Character class syntax [: :] is reserved for future extensions |
2141 | |
2142 | (W) Within regular expression character classes ([]) the syntax beginning |
2143 | with "[:" and ending with ":]" is reserved for future extensions. |
2144 | If you need to represent those character sequences inside a regular |
2145 | expression character class, just quote the square brackets with the |
2146 | backslash: "\[:" and ":\]". |
2147 | |
2148 | =item Ill-formed logical name |%s| in prime_env_iter |
2149 | |
2150 | (W) A warning peculiar to VMS. A logical name was encountered when preparing |
2151 | to iterate over %ENV which violates the syntactic rules governing logical |
2152 | names. Because it cannot be translated normally, it is skipped, and will not |
2153 | appear in %ENV. This may be a benign occurrence, as some software packages |
2154 | might directly modify logical name tables and introduce nonstandard names, |
2155 | or it may indicate that a logical name table has been corrupted. |
2156 | |
2157 | =item regexp too big |
2158 | |
2159 | (F) The current implementation of regular expressions uses shorts as |
2160 | address offsets within a string. Unfortunately this means that if |
2161 | the regular expression compiles to longer than 32767, it'll blow up. |
2162 | Usually when you want a regular expression this big, there is a better |
2163 | way to do it with multiple statements. See L<perlre>. |
2164 | |
2165 | =item Use of "$$<digit>" to mean "${$}<digit>" is deprecated |
2166 | |
2167 | (D) Perl versions before 5.004 misinterpreted any type marker followed |
2168 | by "$" and a digit. For example, "$$0" was incorrectly taken to mean |
2169 | "${$}0" instead of "${$0}". This bug is (mostly) fixed in Perl 5.004. |
2170 | |
2171 | However, the developers of Perl 5.004 could not fix this bug completely, |
2172 | because at least two widely-used modules depend on the old meaning of |
2173 | "$$0" in a string. So Perl 5.004 still interprets "$$<digit>" in the |
2174 | old (broken) way inside strings; but it generates this message as a |
2175 | warning. And in Perl 5.005, this special treatment will cease. |
2176 | |
2177 | =back |
3175b8cd |
2178 | |
ba8251e8 |
2179 | =head1 BUGS |
2180 | |
437784d6 |
2181 | If you find what you think is a bug, you might check the |
14218588 |
2182 | articles recently posted to the comp.lang.perl.misc newsgroup. |
ba8251e8 |
2183 | There may also be information at http://www.perl.com/perl/, the Perl |
2184 | Home Page. |
2185 | |
2186 | If you believe you have an unreported bug, please run the B<perlbug> |
14218588 |
2187 | program included with your release. Make sure to trim your bug down |
ba8251e8 |
2188 | to a tiny but sufficient test case. Your bug report, along with the |
14218588 |
2189 | output of C<perl -V>, will be sent off to perlbug@perl.com to be |
ba8251e8 |
2190 | analysed by the Perl porting team. |
2191 | |
2192 | =head1 SEE ALSO |
2193 | |
2194 | The F<Changes> file for exhaustive details on what changed. |
2195 | |
2196 | The F<INSTALL> file for how to build Perl. |
2197 | |
2198 | The F<README> file for general stuff. |
2199 | |
2200 | The F<Artistic> and F<Copying> files for copyright information. |
2201 | |
2202 | =head1 HISTORY |
2203 | |
a5222a85 |
2204 | Written by Gurusamy Sarathy <F<gsar@activestate.com>>, with many |
2205 | contributions from The Perl Porters. |
ba8251e8 |
2206 | |
2207 | Send omissions or corrections to <F<perlbug@perl.com>>. |
2208 | |
2209 | =cut |