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1 | =head1 NAME |
2 | |
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3 | perldelta - what's new for perl v5.6 (as of v5.005_62) |
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4 | |
5 | =head1 DESCRIPTION |
6 | |
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7 | This is an unsupported alpha release, meant for intrepid Perl developers |
8 | only. The included sources may not even build correctly on some platforms. |
9 | Subscribing to perl5-porters is the best way to monitor and contribute |
10 | to the progress of development releases (see www.perl.org for info). |
11 | |
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12 | This document describes differences between the 5.005 release and this one. |
13 | |
14 | =head1 Incompatible Changes |
15 | |
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16 | =head2 Perl Source Incompatibilities |
17 | |
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18 | Beware that any new warnings that have been added or enhanced old |
19 | warnings are B<not> considered incompatible changes. |
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20 | |
21 | Since all new warnings must be explicitly requested via the C<-w> |
22 | switch or the C<warnings> pragma, it is ultimately the programmer's |
23 | responsibility to ensure that warnings are enabled judiciously. |
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24 | |
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25 | =over 4 |
26 | |
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27 | =item Treatment of list slices of undef has changed |
28 | |
29 | When taking a slice of a literal list (as opposed to a slice of |
30 | an array or hash), Perl used to return an empty list if the |
31 | result happened to be composed of all undef values. |
32 | |
33 | The new behavior is to produce an empty list if (and only if) |
34 | the original list was empty. Consider the following example: |
35 | |
36 | @a = (1,undef,undef,2)[2,1,2]; |
37 | |
38 | The old behavior would have resulted in @a having no elements. |
39 | The new behavior ensures it has three undefined elements. |
40 | |
41 | Note in particular that the behavior of slices of the following |
42 | cases remains unchanged: |
43 | |
44 | @a = ()[1,2]; |
45 | @a = (getpwent)[7,0]; |
46 | @a = (anything_returning_empty_list())[2,1,2]; |
47 | @a = @b[2,1,2]; |
48 | @a = @c{'a','b','c'}; |
49 | |
50 | See L<perldata>. |
51 | |
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52 | =item Possibly changed pseudo-random number generator |
53 | |
54 | In 5.005_0x and earlier, perl's rand() function used the C library |
55 | rand(3) function. As of 5.005_52, Configure tests for drand48(), |
56 | random(), and rand() (in that order) and picks the first one it finds. |
57 | Perl programs that depend on reproducing a specific set of pseudo-random |
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58 | numbers will now likely produce different output. You can use |
59 | C<sh Configure -Drandfunc=rand> to obtain the old behavior. |
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60 | |
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61 | =item Hashing function for hash keys has changed |
62 | |
63 | Perl hashes are not order preserving. The apparently random order |
64 | encountered when iterating on the contents of a hash is determined |
65 | by the hashing algorithm used. To improve the distribution of lower |
66 | bits in the hashed value, the algorithm has changed slightly as of |
67 | 5.005_52. When iterating over hashes, this may yield a random order |
68 | that is B<different> from that of previous versions. |
69 | |
70 | =item C<undef> fails on read only values |
71 | |
72 | Using the C<undef> operator on a readonly value (such as $1) has |
73 | the same effect as assigning C<undef> to the readonly value--it |
74 | throws an exception. |
75 | |
76 | =item Close-on-exec bit may be set on pipe() handles |
77 | |
78 | On systems that support a close-on-exec flag on filehandles, the |
79 | flag will be set for any handles created by pipe(), if that is |
80 | warranted by the value of $^F that may be in effect. Earlier |
81 | versions neglected to set the flag for handles created with |
82 | pipe(). See L<perlfunc/pipe> and L<perlvar/$^F>. |
83 | |
84 | =item Writing C<"$$1"> to mean C<"${$}1"> is unsupported |
85 | |
86 | Perl 5.004 deprecated the interpretation of C<$$1> and |
87 | similar within interpolated strings to mean C<$$ . "1">, |
88 | but still allowed it. |
89 | |
90 | In Perl 5.6 and later, C<"$$1"> always means C<"${$1}">. |
91 | |
92 | =item values(%h) and C<\(%h)> operate on aliases to values, not copies |
93 | |
94 | each(), values() and hashes in a list context return the actual |
95 | values in the hash, instead of copies (as they used to in earlier |
96 | versions). Typical idioms for using these constructs copy the |
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97 | returned values, but this can make a significant difference when |
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98 | creating references to the returned values. |
99 | |
100 | Keys in the hash are still returned as copies when iterating on |
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101 | a hash. |
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102 | |
103 | =item vec(EXPR,OFFSET,BITS) enforces powers-of-two BITS |
104 | |
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105 | vec() generates a run-time error if the BITS argument is not |
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106 | a valid power-of-two integer. |
107 | |
108 | =item Text of some diagnostic output has changed |
109 | |
110 | Most references to internal Perl operations in diagnostics |
111 | have been changed to be more descriptive. This may be an |
112 | issue for programs that may incorrectly rely on the exact |
113 | text of diagnostics for proper functioning. |
114 | |
115 | =item C<%@> has been removed |
116 | |
117 | The undocumented special variable C<%@> that used to accumulate |
118 | "background" errors (such as those that happen in DESTROY()) |
119 | has been removed, because it could potentially result in memory |
120 | leaks. |
121 | |
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122 | =back |
123 | |
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124 | =head2 C Source Incompatibilities |
125 | |
126 | =over 4 |
127 | |
128 | =item C<PERL_POLLUTE> |
129 | |
130 | Release 5.005 grandfathered old global symbol names by providing preprocessor |
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131 | macros for extension source compatibility. As of release 5.6, these |
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132 | preprocessor definitions are not available by default. You need to explicitly |
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133 | compile perl with C<-DPERL_POLLUTE> to get these definitions. For |
134 | extensions still using the old symbols, this option can be |
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135 | specified via MakeMaker: |
136 | |
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137 | perl Makefile.PL POLLUTE=1 |
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138 | |
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139 | =item C<PERL_IMPLICIT_CONTEXT> |
140 | |
141 | This new build option provides a set of macros for all API functions |
142 | such that an implicit interpreter/thread context argument is passed to |
143 | every API function. As a result of this, something like C<sv_setsv(foo,bar)> |
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144 | amounts to a macro invocation that actually translates to something like |
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145 | C<Perl_sv_setsv(my_perl,foo,bar)>. While this is generally expected |
146 | to not have any significant source compatibility issues, the difference |
147 | between a macro and a real function call will need to be considered. |
148 | |
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149 | This means that there B<is> a source compatibility issue as a result of |
150 | this if your extensions attempt to use pointers to any of the Perl API |
151 | functions. |
152 | |
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153 | Note that the above issue is not relevant to the default build of |
154 | Perl, whose interfaces continue to match those of prior versions |
155 | (but subject to the other options described here). |
156 | |
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157 | PERL_IMPLICIT_CONTEXT is automatically enabled whenever Perl is built |
158 | with one of -Dusethreads, -Dusemultiplicity, or both. |
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159 | |
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160 | See L<perlguts/"The Perl API"> for detailed information on the |
161 | ramifications of building Perl using this option. |
162 | |
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163 | =item C<PERL_POLLUTE_MALLOC> |
164 | |
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165 | Enabling Perl's malloc in release 5.005 and earlier caused |
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166 | the namespace of system versions of the malloc family of functions to |
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167 | be usurped by the Perl versions, since by default they used the |
168 | same names. |
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169 | |
170 | Besides causing problems on platforms that do not allow these functions to |
171 | be cleanly replaced, this also meant that the system versions could not |
172 | be called in programs that used Perl's malloc. Previous versions of Perl |
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173 | have allowed this behaviour to be suppressed with the HIDEMYMALLOC and |
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174 | EMBEDMYMALLOC preprocessor definitions. |
175 | |
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176 | As of release 5.6, Perl's malloc family of functions have default names |
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177 | distinct from the system versions. You need to explicitly compile perl with |
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178 | C<-DPERL_POLLUTE_MALLOC> to get the older behaviour. HIDEMYMALLOC |
179 | and EMBEDMYMALLOC have no effect, since the behaviour they enabled is now |
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180 | the default. |
181 | |
182 | Note that these functions do B<not> constitute Perl's memory allocation API. |
183 | See L<perlguts/"Memory Allocation"> for further information about that. |
184 | |
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185 | =back |
186 | |
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187 | =head2 Compatible C Source API Changes |
188 | |
189 | =over |
190 | |
191 | =item C<PATCHLEVEL> is now C<PERL_VERSION> |
192 | |
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193 | The cpp macros C<PERL_REVISION>, C<PERL_VERSION>, and C<PERL_SUBVERSION> |
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194 | are now available by default from perl.h, and reflect the base revision, |
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195 | patchlevel, and subversion respectively. C<PERL_REVISION> had no |
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196 | prior equivalent, while C<PERL_VERSION> and C<PERL_SUBVERSION> were |
197 | previously available as C<PATCHLEVEL> and C<SUBVERSION>. |
198 | |
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199 | The new names cause less pollution of the B<cpp> namespace and reflect what |
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200 | the numbers have come to stand for in common practice. For compatibility, |
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201 | the old names are still supported when F<patchlevel.h> is explicitly |
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202 | included (as required before), so there is no source incompatibility |
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203 | from the change. |
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204 | |
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205 | =item Support for C++ exceptions |
206 | |
207 | change#3386, also needs perlguts documentation |
208 | [TODO - Chip Salzenberg <chip@perlsupport.com>] |
209 | |
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210 | =back |
211 | |
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212 | =head2 Binary Incompatibilities |
213 | |
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214 | The default build of this release is binary compatible with the 5.005 |
215 | release or its maintenance versions. |
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216 | |
217 | The usethreads or usemultiplicity builds are B<not> binary compatible |
218 | with the corresponding builds in 5.005. |
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219 | |
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220 | =head1 Installation and Configuration Improvements |
221 | |
222 | =head2 New Configure flags |
223 | |
224 | The following new flags may be enabled on the Configure command line |
225 | by running Configure with C<-Dflag>. |
226 | |
227 | usemultiplicity |
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228 | |
229 | uselongdouble |
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230 | usemorebits |
231 | uselargefiles |
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232 | |
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233 | =head2 -Dusethreads and -Duse64bits now more daring |
234 | |
235 | The Configure options enabling the use of threads and the use of |
236 | 64-bitness are now more daring in the sense that they no more have |
237 | an explicit list of operating systems of known threads/64-bit |
238 | capabilities. In other words: if your operating system has the |
239 | necessary APIs, you should be able just to go ahead and use them. |
240 | See also L<"64-bit support">. |
241 | |
242 | =head2 Long Doubles |
243 | |
244 | Some platforms have "long doubles", floating point numbers of even |
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245 | larger range than ordinary "doubles". To enable using long doubles for |
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246 | Perl's scalars, use -Duselongdouble. |
247 | |
248 | =head2 -Dusemorebits |
249 | |
250 | You can enable both -Duse64bits and -Dlongdouble by -Dusemorebits. |
251 | See also L<"64-bit support">. |
252 | |
253 | =head2 -Duselargefiles |
254 | |
255 | Some platforms support large files, files larger than two gigabytes. |
256 | See L<"Large file support"> for more information. |
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257 | |
258 | =head2 installusrbinperl |
259 | |
260 | You can use "Configure -Uinstallusrbinperl" which causes installperl |
261 | to skip installing perl also as /usr/bin/perl. This is useful if you |
262 | prefer not to modify /usr/bin for some reason or another but harmful |
263 | because many scripts assume to find Perl in /usr/bin/perl. |
264 | |
265 | =head2 SOCKS support |
266 | |
267 | You can use "Configure -Dusesocks" which causes Perl to probe |
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268 | for the SOCKS (v5, not v4) proxy protocol library, |
269 | http://www.socks.nec.com/ |
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270 | |
271 | =head2 C<-A> flag |
272 | |
273 | You can "post-edit" the Configure variables using the Configure C<-A> |
274 | flag. The editing happens immediately after the platform specific |
275 | hints files have been processed but before the actual configuration |
276 | process starts. Run C<Configure -h> to find out the full C<-A> syntax. |
277 | |
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278 | =head2 Enhanced Installation Directories |
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279 | |
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280 | The installation structure has been enriched to improve the support for |
281 | maintaining multiple versions of perl, to provide locations for |
282 | vendor-supplied modules and scripts, and to ease maintenance of |
283 | locally-added modules and scripts. See the section on Installation |
284 | Directories in the INSTALL file for complete details. For most users |
285 | building and installing from source, the defaults should be fine. |
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286 | |
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287 | =head1 Core Changes |
288 | |
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289 | =head2 Unicode and UTF-8 support |
290 | |
291 | Perl can optionally use UTF-8 as its internal representation for character |
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292 | strings. The C<utf8> pragma enables this support in the current lexical |
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293 | scope. See L<utf8> for more information. |
294 | |
295 | =head2 Lexically scoped warning categories |
296 | |
297 | You can now control the granularity of warnings emitted by perl at a finer |
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298 | level using the C<use warnings> pragma. See L<warnings> and L<perllexwarn> |
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299 | for details. |
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300 | |
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301 | =head2 Lvalue subroutines |
302 | |
303 | WARNING: This is an experimental feature. |
304 | |
305 | change#4081 |
306 | [TODO - Ilya Zakharevich <ilya@math.ohio-state.edu>, |
307 | Tuomas Lukka <lukka@fas.harvard.edu>)] |
308 | |
309 | =head2 "our" declarations |
310 | |
311 | An "our" declaration introduces a value that can be best understood |
312 | as a lexically scoped symbolic alias to a global variable in the |
313 | current package. This is mostly useful as an alternative to the |
314 | C<vars> pragma, but also provides the opportunity to introduce |
315 | typing and other attributes for such variables. See L<perlfunc/our>. |
316 | |
317 | =head2 Weak references |
318 | |
319 | WARNING: This is an experimental feature. |
320 | |
321 | change#3385, also need perlguts documentation |
322 | |
323 | [TODO - Tuomas Lukka <lukka@fas.harvard.edu>] |
324 | |
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325 | =head2 File globbing implemented internally |
326 | |
327 | WARNING: This is currently an experimental feature. Interfaces and |
328 | implementation are likely to change. |
329 | |
330 | Perl can be compiled with -DPERL_INTERNAL_GLOB to use the File::Glob |
331 | implementation of the glob() operator. This avoids using an external |
332 | csh process and the problems associated with it. |
333 | |
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334 | =head2 Binary numbers supported |
335 | |
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336 | Binary numbers are now supported as literals, in s?printf formats, and |
337 | C<oct()>: |
338 | |
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339 | $answer = 0b101010; |
340 | printf "The answer is: %b\n", oct("0b101010"); |
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341 | |
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342 | =head2 Some arrows may be omitted in calls through references |
343 | |
344 | Perl now allows the arrow to be omitted in many constructs |
345 | involving subroutine calls through references. For example, |
346 | C<$foo[10]->('foo')> may now be written C<$foo[10]('foo')>. |
347 | This is rather similar to how the arrow may be omitted from |
348 | C<$foo[10]->{'foo'}>. Note however, that the arrow is still |
349 | required for C<foo(10)->('bar')>. |
350 | |
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351 | =head2 syswrite() ease-of-use |
352 | |
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353 | The length argument of C<syswrite()> has become optional. |
354 | |
355 | =head2 Filehandles can be autovivified |
356 | |
357 | The construct C<open(my $fh, ...)> can be used to create filehandles |
358 | more easily. The filehandle will be automatically closed at the end |
359 | of the scope of $fh, provided there are no other references to it. This |
360 | largely eliminates the need for typeglobs when opening filehandles |
361 | that must be passed around, as in the following example: |
362 | |
363 | sub myopen { |
364 | open my $fh, "@_" |
365 | or die "Can't open '@_': $!"; |
366 | return $fh; |
367 | } |
368 | |
369 | { |
370 | my $f = myopen("</etc/motd"); |
371 | print <$f>; |
372 | # $f implicitly closed here |
373 | } |
374 | |
375 | [TODO - this idiom needs more pod penetration] |
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376 | |
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377 | =head2 64-bit support |
378 | |
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379 | All platforms that have 64-bit integers either (a) natively as longs |
380 | or ints (b) via special compiler flags (c) using long long are able to |
381 | use "quads" (64-integers) as follows: |
382 | |
383 | =over 4 |
384 | |
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385 | =item * |
386 | |
387 | constants (decimal, hexadecimal, octal, binary) in the code |
388 | |
389 | =item * |
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390 | |
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391 | arguments to oct() and hex() |
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392 | |
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393 | =item * |
394 | |
395 | arguments to print(), printf() and sprintf() (flag prefixes ll, L, q) |
396 | |
397 | =item * |
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398 | |
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399 | printed as such |
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400 | |
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401 | =item * |
402 | |
403 | pack() and unpack() "q" and "Q" formats |
404 | |
405 | =item * |
406 | |
407 | in basic arithmetics: + - * / % |
408 | |
409 | =item * |
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410 | |
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411 | vec() (but see the below note about bit arithmetics) |
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412 | |
413 | =back |
414 | |
415 | Note that unless you have the case (a) you will have to configure |
416 | and compile Perl using the -Duse64bits Configure flag. |
417 | |
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418 | Unfortunately bit arithmetics (&, |, ^, ~, <<, >>) for numbers are not |
419 | 64-bit clean, they are explictly forced to be 32-bit. Bit arithmetics |
420 | for bit vectors (created by vec()) are not limited in their width. |
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421 | |
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422 | Last but not least: note that due to Perl's habit of always using |
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423 | floating point numbers the quads are still not true integers. |
424 | When quads overflow their limits (0...18_446_744_073_709_551_615 unsigned, |
425 | -9_223_372_036_854_775_808...9_223_372_036_854_775_807 signed), they |
426 | are silently promoted to floating point numbers, after which they will |
427 | start losing precision (their lower digits). |
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428 | |
429 | =head2 Large file support |
430 | |
431 | If you have filesystems that support "large files" (files larger than |
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432 | 2 gigabytes), you may now also be able to create and access them from |
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433 | Perl. You have to use Configure -Duselargefiles. Turning on the |
434 | large file support turns on also the 64-bit support, for obvious reasons. |
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435 | |
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436 | Note that in addition to requiring a proper file system to do large |
437 | files you may also need to adjust your per-process (or your |
438 | per-system, or per-process-group, or per-user-group) maximum filesize |
439 | limits before running Perl scripts that try to handle large files, |
440 | especially if you intend to write such files. |
441 | |
442 | Finally, in addition to your process/process group maximum filesize |
443 | limits, you may have quota limits on your filesystems that stop you |
444 | (your user id or your user group id) from using large files. |
445 | |
446 | Adjusting your process/user/group/file system/operating system limits |
447 | is outside the scope of Perl core language. For process limits, you |
448 | may try increasing the limits using your shell's limits/limit/ulimit |
449 | command before running Perl. The BSD::Resource extension (not |
450 | included with the standard Perl distribution) may also be of use, it |
451 | offers the getrlimit/setrlimit interface that can be used to adjust |
452 | process resource usage limits, including the maximum filesize limit. |
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453 | |
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454 | =head2 Long doubles |
455 | |
456 | In some systems you may be able to use long doubles to enhance the |
457 | range of precision of your double precision floating point numbers |
458 | (that is, Perl's numbers). Use Configure -Duselongdouble to enable |
459 | this support (if it is available). |
460 | |
461 | =head2 "more bits" |
462 | |
463 | You can Configure -Dusemorebits to turn on both the 64-bit support |
464 | and the long double support. |
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465 | |
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466 | =head2 Better syntax checks on parenthesized unary operators |
467 | |
468 | Expressions such as: |
469 | |
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470 | print defined(&foo,&bar,&baz); |
471 | print uc("foo","bar","baz"); |
472 | undef($foo,&bar); |
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473 | |
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474 | used to be accidentally allowed in earlier versions, and produced |
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475 | unpredictable behaviour. Some produced ancillary warnings |
476 | when used in this way; others silently did the wrong thing. |
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477 | |
478 | The parenthesized forms of most unary operators that expect a single |
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479 | argument now ensure that they are not called with more than one |
480 | argument, making the cases shown above syntax errors. The usual |
481 | behaviour of: |
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482 | |
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483 | print defined &foo, &bar, &baz; |
484 | print uc "foo", "bar", "baz"; |
485 | undef $foo, &bar; |
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486 | |
487 | remains unchanged. See L<perlop>. |
488 | |
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489 | =head2 POSIX character class syntax [: :] supported |
490 | |
491 | For example to match alphabetic characters use /[[:alpha:]]/. |
492 | See L<perlre> for details. |
493 | |
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494 | =head2 Improved C<qw//> operator |
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495 | |
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496 | The C<qw//> operator is now evaluated at compile time into a true list |
497 | instead of being replaced with a run time call to C<split()>. This |
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498 | removes the confusing misbehaviour of C<qw//> in scalar context, which |
499 | had inherited that behaviour from split(). |
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500 | |
501 | Thus: |
502 | |
503 | $foo = ($bar) = qw(a b c); print "$foo|$bar\n"; |
504 | |
505 | now correctly prints "3|a", instead of "2|a". |
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506 | |
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507 | =head2 pack() format 'Z' supported |
508 | |
509 | The new format type 'Z' is useful for packing and unpacking null-terminated |
510 | strings. See L<perlfunc/"pack">. |
511 | |
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512 | =head2 pack() format modifier '!' supported |
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513 | |
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514 | The new format type modifier '!' is useful for packing and unpacking |
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515 | native shorts, ints, and longs. See L<perlfunc/"pack">. |
516 | |
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517 | =head2 pack() and unpack() support counted strings |
518 | |
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519 | The template character '/' can be used to specify a counted string |
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520 | type to be packed or unpacked. See L<perlfunc/"pack">. |
521 | |
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522 | =head2 Comments in pack() templates |
523 | |
524 | The '#' character in a template introduces a comment up to |
525 | end of the line. This facilitates documentation of pack() |
526 | templates. |
527 | |
2b92dfce |
528 | =head2 $^X variables may now have names longer than one character |
529 | |
530 | Formerly, $^X was synonymous with ${"\cX"}, but $^XY was a syntax |
531 | error. Now variable names that begin with a control character may be |
532 | arbitrarily long. However, for compatibility reasons, these variables |
533 | I<must> be written with explicit braces, as C<${^XY}> for example. |
14218588 |
534 | C<${^XYZ}> is synonymous with ${"\cXYZ"}. Variable names with more |
2b92dfce |
535 | than one control character, such as C<${^XY^Z}>, are illegal. |
536 | |
14218588 |
537 | The old syntax has not changed. As before, `^X' may be either a |
538 | literal control-X character or the two-character sequence `caret' plus |
539 | `X'. When braces are omitted, the variable name stops after the |
2b92dfce |
540 | control character. Thus C<"$^XYZ"> continues to be synonymous with |
7711098a |
541 | C<$^X . "YZ"> as before. |
2b92dfce |
542 | |
543 | As before, lexical variables may not have names beginning with control |
544 | characters. As before, variables whose names begin with a control |
14218588 |
545 | character are always forced to be in package `main'. All such variables |
546 | are reserved for future extensions, except those that begin with |
09bef843 |
547 | C<^_>, which may be used by user programs and are guaranteed not to |
14218588 |
548 | acquire special meaning in any future version of Perl. |
2b92dfce |
549 | |
09bef843 |
550 | =head2 C<use attrs> implicit in subroutine attributes |
551 | |
552 | Formerly, if you wanted to mark a subroutine as being a method call or |
553 | as requiring an automatic lock() when it is entered, you had to declare |
554 | that with a C<use attrs> pragma in the body of the subroutine. |
555 | That can now be accomplished with a declaration syntax, like this: |
556 | |
557 | sub mymethod : locked, method ; |
558 | ... |
559 | sub mymethod : locked, method { |
560 | ... |
561 | } |
562 | |
563 | F<AutoSplit.pm> and F<SelfLoader.pm> have been updated to keep the attributes |
564 | with the stubs they provide. See L<attributes>. |
565 | |
a5222a85 |
566 | =head2 Regular expression improvements |
567 | |
568 | change#2827,2373,2372,2365,1813,1800,4112,4158,4215,4301 |
569 | [TODO - Ilya Zakharevich <ilya@math.ohio-state.edu>] |
570 | |
571 | =head2 Overloading improvements |
572 | |
573 | change#2150 |
574 | [TODO - Ilya Zakharevich <ilya@math.ohio-state.edu>] |
575 | |
576 | =head2 open() with more than two arguments |
577 | |
578 | [TODO - Ilya Zakharevich <ilya@math.ohio-state.edu>] |
579 | |
580 | =head2 Support for interpolating named characters |
581 | |
582 | change#4052 |
583 | [TODO - Ilya Zakharevich <ilya@math.ohio-state.edu>] |
584 | |
08cd8952 |
585 | =head2 Experimental support for user-hooks in @INC |
a5222a85 |
586 | |
587 | [TODO - Ken Fox <kfox@ford.com>] |
588 | |
589 | =head2 C<require> and C<do> may be overridden |
590 | |
591 | C<require> and C<do 'file'> operations may be overridden locally |
592 | by importing subroutines of the same name into the current package |
593 | (or globally by importing them into the CORE::GLOBAL:: namespace). |
594 | Overriding C<require> will also affect C<use>, provided the override |
595 | is visible at compile-time. |
596 | See L<perlsub/"Overriding Built-in Functions">. |
597 | |
598 | =head2 New variable $^C reflects C<-c> switch |
599 | |
08cd8952 |
600 | C<$^C> has a boolean value that reflects whether perl is being run |
a5222a85 |
601 | in compile-only mode (i.e. via the C<-c> switch). Since |
602 | BEGIN blocks are executed under such conditions, this variable |
603 | enables perl code to determine whether actions that make sense |
604 | only during normal running are warranted. See L<perlvar>. |
605 | |
606 | =head2 Optional Y2K warnings |
607 | |
608 | If Perl is built with the cpp macro C<PERL_Y2KWARN> defined, |
609 | it emits optional warnings when concatenating the number 19 |
610 | with another number. |
611 | |
612 | This behavior must be specifically enabled when running Configure. |
613 | See L<INSTALL> and L<README.Y2K>. |
614 | |
fbad3eb5 |
615 | =head1 Significant bug fixes |
616 | |
617 | =head2 E<lt>HANDLEE<gt> on empty files |
618 | |
619 | With C<$/> set to C<undef>, slurping an empty file returns a string of |
14218588 |
620 | zero length (instead of C<undef>, as it used to) the first time the |
621 | HANDLE is read. Further reads yield C<undef>. |
fbad3eb5 |
622 | |
623 | This means that the following will append "foo" to an empty file (it used |
14218588 |
624 | to do nothing): |
fbad3eb5 |
625 | |
626 | perl -0777 -pi -e 's/^/foo/' empty_file |
627 | |
14218588 |
628 | The behaviour of: |
fbad3eb5 |
629 | |
630 | perl -pi -e 's/^/foo/' empty_file |
631 | |
632 | is unchanged (it continues to leave the file empty). |
633 | |
0244c3a4 |
634 | =head2 C<eval '...'> improvements |
635 | |
636 | Line numbers (as reflected by caller() and most diagnostics) within |
637 | C<eval '...'> were often incorrect when here documents were involved. |
638 | This has been corrected. |
639 | |
640 | Lexical lookups for variables appearing in C<eval '...'> within |
641 | functions that were themselves called within an C<eval '...'> were |
14218588 |
642 | searching the wrong place for lexicals. The lexical search now |
643 | correctly ends at the subroutine's block boundary. |
0244c3a4 |
644 | |
645 | Parsing of here documents used to be flawed when they appeared as |
646 | the replacement expression in C<eval 's/.../.../e'>. This has |
647 | been fixed. |
648 | |
a5222a85 |
649 | =head2 All compilation errors are true errors |
650 | |
651 | Some "errors" encountered at compile time were by neccessity |
652 | generated as warnings followed by eventual termination of the |
653 | program. This enabled more such errors to be reported in a |
654 | single run, rather than causing a hard stop at the first error |
655 | that was encountered. |
656 | |
657 | The mechanism for reporting such errors has been reimplemented |
658 | to queue compile-time errors and report them at the end of the |
659 | compilation as true errors rather than as warnings. This fixes |
08cd8952 |
660 | cases where error messages leaked through in the form of warnings |
661 | when code was compiled at run time using C<eval STRING>, and |
662 | also allows such errors to be reliably trapped using __DIE__ hooks. |
a5222a85 |
663 | |
45bc9206 |
664 | =head2 Automatic flushing of output buffers |
665 | |
14218588 |
666 | fork(), exec(), system(), qx//, and pipe open()s now flush buffers |
667 | of all files opened for output when the operation |
668 | was attempted. This mostly eliminates confusing |
45bc9206 |
669 | buffering mishaps suffered by users unaware of how Perl internally |
14218588 |
670 | handles I/O. |
45bc9206 |
671 | |
af8c498a |
672 | =head2 Better diagnostics on meaningless filehandle operations |
673 | |
674 | Constructs such as C<open(E<lt>FHE<gt>)> and C<close(E<lt>FHE<gt>)> |
675 | are compile time errors. Attempting to read from filehandles that |
676 | were opened only for writing will now produce warnings (just as |
677 | writing to read-only filehandles does). |
678 | |
a5222a85 |
679 | =head2 Where possible, buffered data discarded from duped input filehandle |
680 | |
681 | C<open(NEW, "E<lt>&OLD")> now attempts to discard any data that |
682 | was previously read and buffered in C<OLD> before duping the handle. |
683 | On platforms where doing this is allowed, the next read operation |
684 | on C<NEW> will return the same data as the corresponding operation |
685 | on C<OLD>. Formerly, it would have returned the data from the start |
686 | of the following disk block instead. |
687 | |
688 | =head2 system(), backticks and pipe open now reflect exec() failure |
689 | |
690 | On Unix and similar platforms, system(), qx() and open(FOO, "cmd |") |
691 | etc., are implemented via fork() and exec(). When the underlying |
692 | exec() fails, earlier versions did not report the error properly, |
693 | since the exec() happened to be in a different process. |
694 | |
695 | The child process now communicates with the parent about the |
437784d6 |
696 | error in launching the external command, which allows these |
a5222a85 |
697 | constructs to return with their usual error value and set $!. |
698 | |
699 | =head2 Implicitly closed filehandles are safer |
700 | |
701 | Sometimes implicitly closed filehandles (as when they are localized, |
702 | and Perl automatically closes them on exiting the scope) could |
703 | inadvertently set $? or $!. This has been corrected. |
704 | |
705 | =head2 C<(\$)> prototype and C<$foo{a}> |
706 | |
707 | An scalar reference prototype now correctly allows a hash or |
708 | array element in that slot. |
709 | |
710 | =head2 Pseudo-hashes work better |
711 | |
712 | Dereferencing some types of reference values in a pseudo-hash, |
713 | such as C<$ph->{foo}[1]>, was accidentally disallowed. This has |
714 | been corrected. |
715 | |
716 | When applied to a pseudo-hash element, exists() now reports whether |
717 | the specified value exists, not merely if the key is valid. |
718 | |
719 | =head2 C<goto &sub> and AUTOLOAD |
720 | |
08cd8952 |
721 | The C<goto &sub> construct works correctly when C<&sub> happens |
a5222a85 |
722 | to be autoloaded. |
723 | |
724 | =head2 C<-bareword> allowed under C<use integer> |
725 | |
726 | The autoquoting of barewords preceded by C<-> did not work |
727 | in prior versions when the C<integer> pragma was enabled. |
728 | This has been fixed. |
729 | |
730 | =head2 Boolean assignment operators are legal lvalues |
731 | |
732 | Constructs such as C<($a ||= 2) += 1> are now allowed. |
733 | |
734 | =head2 C<sort $coderef @foo> allowed |
735 | |
736 | sort() did not accept a subroutine reference as the comparison |
08cd8952 |
737 | function in earlier versions. This is now permitted. |
a5222a85 |
738 | |
739 | =head2 Failures in DESTROY() |
740 | |
741 | When code in a destructor threw an exception, it went unnoticed |
742 | in earlier versions of Perl, unless someone happened to be |
743 | looking in $@ just after the point the destructor happened to |
744 | run. Such failures are now visible as warnings when warnings are |
745 | enabled. |
746 | |
747 | =head2 Locale bugs fixed |
54195c32 |
748 | |
437784d6 |
749 | printf() and sprintf() previously reset the numeric locale |
67d3893f |
750 | back to the default "C" locale. This has been fixed. |
751 | |
752 | Numbers formatted according to the local numeric locale |
753 | (such as using a decimal comma instead of a decimal dot) caused |
754 | "isn't numeric" warnings, even while the operations accessing |
755 | those numbers produced correct results. The warnings are gone. |
54195c32 |
756 | |
a5222a85 |
757 | =head2 Memory leaks |
758 | |
759 | The C<eval 'return sub {...}'> construct could sometimes leak |
760 | memory. This has been fixed. |
761 | |
762 | Operations that aren't filehandle constructors used to leak memory |
763 | when used on invalid filehandles. This has been fixed. |
764 | |
765 | Constructs that modified C<@_> could fail to deallocate values |
766 | in C<@_> and thus leak memory. This has been corrected. |
767 | |
768 | =head2 Spurious subroutine stubs after failed subroutine calls |
769 | |
770 | Perl could sometimes create empty subroutine stubs when a |
771 | subroutine was not found in the package. Such cases stopped |
772 | later method lookups from progressing into base packages. |
773 | This has been corrected. |
774 | |
775 | =head2 Consistent numeric conversions |
776 | |
777 | change#3378,3318 |
778 | [TODO - Ilya Zakharevich <ilya@math.ohio-state.edu>] |
779 | |
780 | =head2 Taint failures under C<-U> |
781 | |
782 | When running in unsafe mode, taint violations could sometimes |
783 | cause silent failures. This has been fixed. |
784 | |
785 | =head2 END blocks and the C<-c> switch |
786 | |
787 | Prior versions used to run BEGIN B<and> END blocks when Perl was |
788 | run in compile-only mode. Since this is typically not the expected |
08cd8952 |
789 | behavior, END blocks are not executed anymore when the C<-c> switch |
a5222a85 |
790 | is used. |
791 | |
792 | Note that something resembling the previous behavior can still be |
f5daac4a |
793 | obtained by putting C<BEGIN { $^C = 0; exit; }> at the very end of |
a5222a85 |
794 | the top level source file. |
795 | |
796 | =head2 Potential to leak DATA filehandles |
797 | |
798 | Using the C<__DATA__> token creates an implicit filehandle to |
799 | the file that contains the token. It is the program's |
800 | responsibility to close it when it is done reading from it. |
801 | |
802 | This caveat is now better explained in the documentation. |
803 | See L<perldata>. |
804 | |
805 | =head2 Diagnostics follow STDERR |
806 | |
807 | Diagnostic output now goes to whichever file the C<STDERR> handle |
808 | is pointing at, instead of always going to the underlying C runtime |
809 | library's C<stderr>. |
810 | |
811 | =head2 Other fixes for better diagnostics |
812 | |
437784d6 |
813 | Line numbers are no longer suppressed (under most likely circumstances) |
a5222a85 |
814 | during the global destruction phase. |
815 | |
816 | Diagnostics emitted from code running in threads other than the main |
817 | thread are now accompanied by the thread ID. |
818 | |
819 | Embedded null characters in diagnostics now actually show up. They |
820 | used to truncate the message in prior versions. |
821 | |
822 | $foo::a and $foo::b are now exempt from "possible typo" warnings only |
823 | if sort() is encountered in package foo. |
824 | |
501fbaef |
825 | Unrecognized alphabetic escapes encountered when parsing quote |
a5222a85 |
826 | constructs now generate a warning, since they may take on new |
827 | semantics in later versions of Perl. |
828 | |
829 | =head1 Performance enhancements |
830 | |
831 | =head2 Simple sort() using { $a <=> $b } and the like are optimized |
832 | |
08cd8952 |
833 | Many common sort() operations using a simple inlined block are now |
a5222a85 |
834 | optimized for faster performance. |
835 | |
836 | =head2 Optimized assignments to lexical variables |
837 | |
838 | Certain operations in the RHS of assignment statements have been |
839 | optimized to directly set the lexical variable on the LHS, |
840 | eliminating redundant copying overheads. |
841 | |
842 | =head2 Method lookups optimized |
843 | |
844 | [TODO - Chip Salzenberg <chip@perlsupport.com>] |
845 | |
846 | =head2 Faster mechanism to invoke XSUBs |
847 | |
848 | change#4044,4125 |
849 | [TODO - Ilya Zakharevich <ilya@math.ohio-state.edu>] |
850 | |
851 | =head2 Perl_malloc() improvements |
852 | |
853 | change#4237 |
854 | [TODO - Ilya Zakharevich <ilya@math.ohio-state.edu>] |
855 | |
856 | =head2 Faster subroutine calls |
857 | |
858 | Minor changes in how subroutine calls are handled internally |
859 | provide marginal improvements in performance. |
860 | |
861 | =head1 Platform specific changes |
862 | |
863 | =head2 Additional supported platforms |
ba8251e8 |
864 | |
5fdc711f |
865 | =over 4 |
866 | |
867 | =item * |
868 | |
6c67e1bb |
869 | VM/ESA is now supported. |
870 | |
5fdc711f |
871 | =item * |
872 | |
ee3907e2 |
873 | Siemens BS2000 is now supported under the POSIX Shell. |
874 | |
875 | =item * |
876 | |
2bb14304 |
877 | The Mach CThreads (NEXTSTEP, OPENSTEP) are now supported by the Thread |
878 | extension. |
6c67e1bb |
879 | |
5fdc711f |
880 | =item * |
881 | |
ee3907e2 |
882 | GNU/Hurd is now supported. |
6c67e1bb |
883 | |
00ad96e1 |
884 | =item * |
885 | |
886 | Rhapsody is now supported. |
887 | |
27806c82 |
888 | =item * |
889 | |
890 | EPOC is is now supported (on Psion 5). |
891 | |
5fdc711f |
892 | =back |
893 | |
a5222a85 |
894 | =head2 DOS |
895 | |
896 | [TODO - Laszlo Molnar <laszlo.molnar@eth.ericsson.se>] |
897 | |
898 | =head2 OS/2 |
899 | |
900 | [TODO - Ilya Zakharevich <ilya@math.ohio-state.edu>] |
901 | |
902 | =head2 VMS |
903 | |
904 | [TODO - Charles Bailey <bailey@newman.upenn.edu>] |
905 | |
906 | =head2 Win32 |
907 | |
908 | Site library searches failed to look for ".../site/5.XXX/lib" |
909 | if ".../site/5.XXXYY/lib" wasn't found. This has been corrected. |
910 | |
911 | When given a pathname that consists only of a drivename, such |
912 | as C<A:>, opendir() and stat() now use the current working |
913 | directory for the drive rather than the drive root. |
914 | |
915 | The builtin XSUB functions in the Win32:: namespace are |
916 | documented. See L<Win32>. |
917 | |
918 | $^X now contains the full path name of the running executable. |
919 | |
920 | A Win32::GetLongPathName() function is provided to complement |
921 | Win32::GetFullPathName() and Win32::GetShortPathName(). See L<Win32>. |
922 | |
923 | POSIX::uname() is supported. |
924 | |
925 | system(1,...) now returns true process IDs rather than process |
926 | handles. kill() accepts any real process id, rather than strictly |
927 | return values from system(1,...). |
928 | |
929 | The C<Shell> module is supported. |
930 | |
883d36a6 |
931 | Rudimentary support for building under command.com in Windows 95 |
932 | has been added. |
933 | |
a5222a85 |
934 | [TODO - GSAR] |
935 | |
6c67e1bb |
936 | =head1 New tests |
937 | |
938 | =over 4 |
939 | |
09bef843 |
940 | =item lib/attrs |
941 | |
942 | Compatibility tests for C<sub : attrs> vs the older C<use attrs>. |
943 | |
944 | =item lib/io_const |
6c67e1bb |
945 | |
946 | IO constants (SEEK_*, _IO*). |
14218588 |
947 | |
09bef843 |
948 | =item lib/io_dir |
6c67e1bb |
949 | |
950 | Directory-related IO methods (new, read, close, rewind, tied delete). |
951 | |
09bef843 |
952 | =item lib/io_multihomed |
6c67e1bb |
953 | |
954 | INET sockets with multi-homed hosts. |
955 | |
09bef843 |
956 | =item lib/io_poll |
6c67e1bb |
957 | |
958 | IO poll(). |
959 | |
09bef843 |
960 | =item lib/io_unix |
6c67e1bb |
961 | |
962 | UNIX sockets. |
963 | |
09bef843 |
964 | =item op/attrs |
965 | |
966 | Regression tests for C<my ($x,@y,%z) : attrs> and <sub : attrs>. |
967 | |
6c67e1bb |
968 | =item op/filetest |
969 | |
970 | File test operators. |
971 | |
972 | =item op/lex_assign |
973 | |
5fdc711f |
974 | Verify operations that access pad objects (lexicals and temporaries). |
6c67e1bb |
975 | |
976 | =back |
e02fdbd2 |
977 | |
ba8251e8 |
978 | =head1 Modules and Pragmata |
979 | |
3e8c4fa0 |
980 | =head2 Modules |
981 | |
b7d8191e |
982 | =over 4 |
983 | |
09bef843 |
984 | =item attributes |
985 | |
986 | While used internally by Perl as a pragma, this module also |
987 | provides a way to fetch subroutine and variable attributes. |
988 | See L<attributes>. |
989 | |
a5222a85 |
990 | =item B |
991 | |
501fbaef |
992 | The Perl Compiler suite has been extensively reworked for this |
993 | release. |
994 | |
a5222a85 |
995 | [TODO - Vishal Bhatia <vishal@gol.com>, |
996 | Nick Ing-Simmons <nick@ni-s.u-net.com>] |
997 | |
f29c64d6 |
998 | =item ByteLoader |
999 | |
a5222a85 |
1000 | The ByteLoader is a dedicated extension to generate and run |
f29c64d6 |
1001 | Perl bytecode. See L<ByteLoader>. |
1002 | |
a5222a85 |
1003 | =item constant |
1004 | |
1005 | References can now be used. See L<constant>. |
1006 | |
1007 | =item charnames |
1008 | |
1009 | change#4052 |
1010 | [TODO - Ilya Zakharevich <ilya@math.ohio-state.edu>] |
1011 | |
1012 | =item Data::Dumper |
1013 | |
1014 | A C<Maxdepth> setting can be specified to avoid venturing |
73b437c8 |
1015 | too deeply into deep data structures. See L<Data::Dumper>. |
a5222a85 |
1016 | |
1017 | Dumping C<qr//> objects works correctly. |
1018 | |
1019 | =item DB |
1020 | |
1021 | C<DB> is an experimental module that exposes a clean abstraction |
1022 | to Perl's debugging API. |
1023 | |
1024 | =item DB_File |
1025 | |
1026 | [TODO - Paul Marquess <paul.marquess@bt.com>] |
1027 | |
f29c64d6 |
1028 | =item Devel::DProf |
1029 | |
9e107c59 |
1030 | Devel::DProf, a Perl source code profiler has been added. See |
1031 | L<Devel::DProf> and L<dprofpp>. |
f29c64d6 |
1032 | |
b7d8191e |
1033 | =item Dumpvalue |
1034 | |
437784d6 |
1035 | The Dumpvalue module provides screen dumps of Perl data. |
b7d8191e |
1036 | |
1037 | =item Benchmark |
1038 | |
54e82ce5 |
1039 | Overall, Benchmark results exhibit lower average error and better timing |
1040 | accuracy. |
1041 | |
868cb350 |
1042 | You can now run tests for I<n> seconds instead of guessing the right |
14218588 |
1043 | number of tests to run: e.g. timethese(-5, ...) will run each |
1044 | code for at least 5 CPU seconds. Zero as the "number of repetitions" |
155776c0 |
1045 | means "for at least 3 CPU seconds". The output format has also |
14218588 |
1046 | changed. For example: |
155776c0 |
1047 | |
54e82ce5 |
1048 | use Benchmark;$x=3;timethese(-5,{a=>sub{$x*$x},b=>sub{$x**2}}) |
155776c0 |
1049 | |
1050 | will now output something like this: |
1051 | |
54e82ce5 |
1052 | Benchmark: running a, b, each for at least 5 CPU seconds... |
1053 | a: 5 wallclock secs ( 5.77 usr + 0.00 sys = 5.77 CPU) @ 200551.91/s (n=1156516) |
1054 | b: 4 wallclock secs ( 5.00 usr + 0.02 sys = 5.02 CPU) @ 159605.18/s (n=800686) |
155776c0 |
1055 | |
1056 | New features: "each for at least N CPU seconds...", "wallclock secs", |
1057 | and the "@ operations/CPU second (n=operations)". |
b7d8191e |
1058 | |
54e82ce5 |
1059 | timethese() now returns a reference to a hash of Benchmark objects containing |
1060 | the test results, keyed on the names of the tests. |
1061 | |
1062 | timethis() now returns the iterations field in the Benchmark result object |
1063 | instead of 0. |
1064 | |
1065 | timethese(), timethis(), and the new cmpthese() (see below) can also take |
1066 | a format specifier of 'none' to suppress output. |
1067 | |
1068 | A new function countit() is just like timeit() except that it takes a |
1069 | TIME instead of a COUNT. |
1070 | |
1071 | A new function cmpthese() prints a chart comparing the results of each test |
1072 | returned from a timethese() call. For each possible pair of tests, the |
1073 | percentage speed difference (iters/sec or seconds/iter) is shown. |
1074 | |
1075 | For other details, see L<Benchmark>. |
a5222a85 |
1076 | |
f505c983 |
1077 | =item Devel::Peek |
1078 | |
1079 | The Devel::Peek module provides access to the internal representation |
14218588 |
1080 | of Perl variables and data. It is a data debugging tool for the XS programmer. |
f505c983 |
1081 | |
a5222a85 |
1082 | =item ExtUtils::MakeMaker |
1083 | |
1084 | change#4135, also needs docs in module pod |
1085 | [TODO - Ilya Zakharevich <ilya@math.ohio-state.edu>] |
1086 | |
b7d8191e |
1087 | =item Fcntl |
1088 | |
1089 | More Fcntl constants added: F_SETLK64, F_SETLKW64, O_LARGEFILE for |
14218588 |
1090 | large (more than 4G) file access (64-bit support is not yet |
b7d8191e |
1091 | working, though, so no need to get overly excited), Free/Net/OpenBSD |
1092 | locking behaviour flags F_FLOCK, F_POSIX, Linux F_SHLCK, and |
1093 | O_ACCMODE: the mask of O_RDONLY, O_WRONLY, and O_RDWR. |
1094 | |
a5222a85 |
1095 | =item File::Compare |
1096 | |
1097 | A compare_text() function has been added, which allows custom |
1098 | comparison functions. See L<File::Compare>. |
1099 | |
1100 | =item File::Find |
1101 | |
1102 | File::Find now works correctly when the wanted() function is either |
1103 | autoloaded or is a symbolic reference. |
1104 | |
08cd8952 |
1105 | A bug that caused File::Find to lose track of the working directory |
a5222a85 |
1106 | when pruning top-level directories has been fixed. |
1107 | |
becf2bd3 |
1108 | =item File::Glob |
1109 | |
1110 | This extension implements BSD-style file globbing. It will also be |
1111 | used for the internal implementation of the glob() operator if |
1112 | Perl was compiled with -DPERL_INTERNAL_GLOB. See L<File::Glob>. |
1113 | |
f505c983 |
1114 | =item File::Spec |
1115 | |
1116 | New methods have been added to the File::Spec module: devnull() returns |
19799a22 |
1117 | the name of the null device (/dev/null on Unix) and tmpdir() the name of |
14218588 |
1118 | the temp directory (normally /tmp on Unix). There are now also methods |
f505c983 |
1119 | to convert between absolute and relative filenames: abs2rel() and |
14218588 |
1120 | rel2abs(). For compatibility with operating systems that specify volume |
1121 | names in file paths, the splitpath(), splitdir(), and catdir() methods |
f505c983 |
1122 | have been added. |
1123 | |
1124 | =item File::Spec::Functions |
1125 | |
1126 | The new File::Spec::Functions modules provides a function interface |
14218588 |
1127 | to the File::Spec module. Allows shorthand |
f505c983 |
1128 | |
14218588 |
1129 | $fullname = catfile($dir1, $dir2, $file); |
f505c983 |
1130 | |
1131 | instead of |
1132 | |
14218588 |
1133 | $fullname = File::Spec->catfile($dir1, $dir2, $file); |
f505c983 |
1134 | |
a5222a85 |
1135 | =item Getopt::Long |
1136 | |
c6edd1b7 |
1137 | Getopt::Long licensing has changed to allow the Perl Artistic License |
1138 | as well as the GPL. It used to be GPL only, which got in the way of |
1139 | non-GPL applications that wanted to use Getopt::Long. |
1140 | |
1141 | Getopt::Long encourages the use of Pod::Usage to produce help |
1142 | messages. For example: |
1143 | |
1144 | use Getopt::Long; |
1145 | use Pod::Usage; |
1146 | my $man = 0; |
1147 | my $help = 0; |
1148 | GetOptions('help|?' => \$help, man => \$man) or pod2usage(2); |
1149 | pod2usage(1) if $help; |
1150 | pod2usage(-exitstatus => 0, -verbose => 2) if $man; |
1151 | |
1152 | __END__ |
1153 | |
1154 | =head1 NAME |
1155 | |
1156 | sample - Using GetOpt::Long and Pod::Usage |
1157 | |
1158 | =head1 SYNOPSIS |
1159 | |
1160 | sample [options] [file ...] |
1161 | |
1162 | Options: |
1163 | -help brief help message |
1164 | -man full documentation |
1165 | |
1166 | =head1 OPTIONS |
1167 | |
1168 | =over 8 |
1169 | |
1170 | =item B<-help> |
1171 | |
1172 | Print a brief help message and exits. |
1173 | |
1174 | =item B<-man> |
1175 | |
1176 | Prints the manual page and exits. |
1177 | |
1178 | =back |
1179 | |
1180 | =head1 DESCRIPTION |
1181 | |
1182 | B<This program> will read the given input file(s) and do someting |
1183 | useful with the contents thereof. |
1184 | |
1185 | =cut |
1186 | |
1187 | See L<Pod::Usage> for details. |
1188 | |
1189 | A bug that prevented the non-option call-back E<lt>E<gt> from being |
1190 | specified as the first argument has been fixed. |
1191 | |
1192 | To specify the characters E<lt> and E<gt> as option starters, use |
1193 | E<gt>E<lt>. Note, however, that changing option starters is strongly |
1194 | deprecated. |
a5222a85 |
1195 | |
1196 | =item IO |
1197 | |
1198 | write() and syswrite() will now accept a single-argument |
1199 | form of the call, for consistency with Perl's syswrite(). |
1200 | |
1201 | You can now create a TCP-based IO::Socket::INET without forcing |
1202 | a connect attempt. This allows you to configure its options |
1203 | (like making it non-blocking) and then call connect() manually. |
1204 | |
1205 | A bug that prevented the IO::Socket::protocol() accessor |
1206 | from ever returning the correct value has been corrected. |
1207 | |
1208 | =item JPL |
1209 | |
1210 | Java Perl Lingo is now distributed with Perl. See jpl/README |
1211 | for more information. |
1212 | |
883d36a6 |
1213 | =item lib |
1214 | |
1215 | C<use lib> now weeds out any trailing duplicate entries. |
1216 | C<no lib> removes all named entries. |
1217 | |
e16b8f49 |
1218 | =item Math::BigInt |
1219 | |
437784d6 |
1220 | The bitwise operations C<E<lt>E<lt>>, C<E<gt>E<gt>>, C<&>, C<|>, |
e16b8f49 |
1221 | and C<~> are now supported on bigints. |
1222 | |
b7d8191e |
1223 | =item Math::Complex |
7711098a |
1224 | |
14218588 |
1225 | The accessor methods Re, Im, arg, abs, rho, and theta can now also |
868cb350 |
1226 | act as mutators (accessor $z->Re(), mutator $z->Re(3)). |
b7d8191e |
1227 | |
1228 | =item Math::Trig |
1229 | |
14218588 |
1230 | A little bit of radial trigonometry (cylindrical and spherical), |
1231 | radial coordinate conversions, and the great circle distance were added. |
b7d8191e |
1232 | |
a5222a85 |
1233 | =item Pod::Parser |
1234 | |
1235 | [TODO - Brad Appleton <bradapp@enteract.com>] |
1236 | |
1237 | =item Pod::Text and Pod::Man |
1238 | |
1239 | [TODO - Russ Allbery <rra@stanford.edu>] |
1240 | |
f4b9d880 |
1241 | =item SDBM_File |
1242 | |
1243 | An EXISTS method has been added to this module (and sdbm_exists() has |
1244 | been added to the underlying sdbm library), so one can now call exists |
14218588 |
1245 | on an SDBM_File tied hash and get the correct result, rather than a |
f4b9d880 |
1246 | runtime error. |
1247 | |
a5222a85 |
1248 | A bug that may have caused data loss when more than one disk block |
1249 | happens to be read from the database in a single FETCH() has been |
1250 | fixed. |
1251 | |
06ef4121 |
1252 | =item Time::Local |
1253 | |
1254 | The timelocal() and timegm() functions used to silently return bogus |
437784d6 |
1255 | results when the date fell outside the machine's integer range. They |
a5222a85 |
1256 | now consistently croak() if the date falls in an unsupported range. |
06ef4121 |
1257 | |
8fe0a5c4 |
1258 | =item Win32 |
1259 | |
1260 | The error return value in list context has been changed for all functions |
14218588 |
1261 | that return a list of values. Previously these functions returned a list |
1262 | with a single element C<undef> if an error occurred. Now these functions |
1263 | return the empty list in these situations. This applies to the following |
8fe0a5c4 |
1264 | functions: |
1265 | |
14218588 |
1266 | Win32::FsType |
1267 | Win32::GetOSVersion |
8fe0a5c4 |
1268 | |
1269 | The remaining functions are unchanged and continue to return C<undef> on |
1270 | error even in list context. |
1271 | |
1272 | The Win32::SetLastError(ERROR) function has been added as a complement |
1273 | to the Win32::GetLastError() function. |
1274 | |
1275 | The new Win32::GetFullPathName(FILENAME) returns the full absolute |
14218588 |
1276 | pathname for FILENAME in scalar context. In list context it returns |
1277 | a two-element list containing the fully qualified directory name and |
501fbaef |
1278 | the filename. See L<Win32>. |
8fe0a5c4 |
1279 | |
9fe6733a |
1280 | =item DBM Filters |
1281 | |
1282 | A new feature called "DBM Filters" has been added to all the |
14218588 |
1283 | DBM modules--DB_File, GDBM_File, NDBM_File, ODBM_File, and SDBM_File. |
1284 | DBM Filters add four new methods to each DBM module: |
9fe6733a |
1285 | |
1286 | filter_store_key |
1287 | filter_store_value |
1288 | filter_fetch_key |
1289 | filter_fetch_value |
1290 | |
14218588 |
1291 | These can be used to filter key-value pairs before the pairs are |
9fe6733a |
1292 | written to the database or just after they are read from the database. |
1293 | See L<perldbmfilter> for further information. |
1294 | |
b7d8191e |
1295 | =back |
3e8c4fa0 |
1296 | |
1297 | =head2 Pragmata |
1298 | |
437784d6 |
1299 | C<use attrs> is now obsolete, and is only provided for |
09bef843 |
1300 | backward-compatibility. It's been replaced by the C<sub : attributes> |
1301 | syntax. See L<perlsub/"Subroutine Attributes"> and L<attributes>. |
1302 | |
14218588 |
1303 | C<use utf8> to enable UTF-8 and Unicode support. |
43165c05 |
1304 | |
1305 | C<use caller 'encoding'> allows modules to inherit pragmatic attributes |
1306 | from the caller's context. C<encoding> is currently the only supported |
1307 | attribute. |
9d73390d |
1308 | |
4438c4b7 |
1309 | Lexical warnings pragma, C<use warnings;>, to control optional warnings. |
a5222a85 |
1310 | See L<perllexwarn>. |
6c67e1bb |
1311 | |
67d3893f |
1312 | C<use filetest> to control the behaviour of filetests (C<-r> C<-w> |
1313 | ...). Currently only one subpragma implemented, "use filetest |
1314 | 'access';", that uses access(2) or equivalent to check permissions |
1315 | instead of using stat(2) as usual. This matters in filesystems |
1316 | where there are ACLs (access control lists): the stat(2) might lie, |
1317 | but access(2) knows better. |
6c67e1bb |
1318 | |
ba8251e8 |
1319 | =head1 Utility Changes |
1320 | |
a5222a85 |
1321 | =head2 h2ph |
1322 | |
1323 | [TODO - Kurt Starsinic <kstar@chapin.edu>] |
1324 | |
1325 | =head2 perlcc |
1326 | |
1327 | C<perlcc> now supports the C and Bytecode backends. By default, |
1328 | it generates output from the simple C backend rather than the |
1329 | optimized C backend. |
1330 | |
1331 | Support for non-Unix platforms has been improved. |
1332 | |
1333 | =head2 h2xs |
1334 | |
1335 | change#4232 |
1336 | [TODO - Ilya Zakharevich <ilya@math.ohio-state.edu>] |
e02fdbd2 |
1337 | |
ba8251e8 |
1338 | =head1 Documentation Changes |
1339 | |
5fdc711f |
1340 | =over 4 |
1341 | |
883d36a6 |
1342 | =item perlcompile.pod |
1343 | |
1344 | An introduction to using the Perl Compiler suite. |
1345 | |
c7c04614 |
1346 | =item perlfilter.pod |
1347 | |
1348 | An introduction to writing Perl source filters. |
1349 | |
883d36a6 |
1350 | =item perlhack.pod |
1351 | |
1352 | Some guidelines for hacking the Perl source code. |
1353 | |
5fdc711f |
1354 | =item perlopentut.pod |
f8284313 |
1355 | |
5fdc711f |
1356 | A tutorial on using open() effectively. |
1357 | |
1358 | =item perlreftut.pod |
1359 | |
1360 | A tutorial that introduces the essentials of references. |
1361 | |
14218588 |
1362 | =item perltootc.pod |
1363 | |
1364 | A tutorial on managing class data for object modules. |
1365 | |
5fdc711f |
1366 | =back |
e02fdbd2 |
1367 | |
73b437c8 |
1368 | =head1 New or Changed Diagnostics |
ba8251e8 |
1369 | |
a99ba403 |
1370 | =over 4 |
1371 | |
09bef843 |
1372 | =item "my sub" not yet implemented |
1373 | |
1374 | (F) Lexically scoped subroutines are not yet implemented. Don't try that |
1375 | yet. |
1376 | |
a99ba403 |
1377 | =item '!' allowed only after types %s |
1378 | |
1379 | (F) The '!' is allowed in pack() and unpack() only after certain types. |
1380 | See L<perlfunc/pack>. |
1381 | |
1382 | =item / cannot take a count |
1383 | |
1384 | (F) You had an unpack template indicating a counted-length string, |
1385 | but you have also specified an explicit size for the string. |
1386 | See L<perlfunc/pack>. |
1387 | |
1388 | =item / must be followed by a, A or Z |
1389 | |
1390 | (F) You had an unpack template indicating a counted-length string, |
1391 | which must be followed by one of the letters a, A or Z |
1392 | to indicate what sort of string is to be unpacked. |
1393 | See L<perlfunc/pack>. |
1394 | |
1395 | =item / must be followed by a*, A* or Z* |
1396 | |
437784d6 |
1397 | (F) You had a pack template indicating a counted-length string, |
a99ba403 |
1398 | Currently the only things that can have their length counted are a*, A* or Z*. |
1399 | See L<perlfunc/pack>. |
1400 | |
1401 | =item / must follow a numeric type |
1402 | |
1403 | (F) You had an unpack template that contained a '#', |
1404 | but this did not follow some numeric unpack specification. |
1405 | See L<perlfunc/pack>. |
1406 | |
1407 | =item Repeat count in pack overflows |
1408 | |
1409 | (F) You can't specify a repeat count so large that it overflows |
1410 | your signed integers. See L<perlfunc/pack>. |
1411 | |
1412 | =item Repeat count in unpack overflows |
1413 | |
1414 | (F) You can't specify a repeat count so large that it overflows |
1415 | your signed integers. See L<perlfunc/unpack>. |
1416 | |
1417 | =item /%s/: Unrecognized escape \\%c passed through |
1418 | |
1419 | (W) You used a backslash-character combination which is not recognized |
1420 | by Perl. This combination appears in an interpolated variable or a |
1028017a |
1421 | C<'>-delimited regular expression. The character was understood literally. |
1422 | |
1423 | =item /%s/: Unrecognized escape \\%c in character class passed through |
1424 | |
1425 | (W) You used a backslash-character combination which is not recognized |
1426 | by Perl inside character classes. The character was understood literally. |
a99ba403 |
1427 | |
1428 | =item /%s/ should probably be written as "%s" |
1429 | |
1430 | (W) You have used a pattern where Perl expected to find a string, |
437784d6 |
1431 | as in the first argument to C<join>. Perl will treat the true |
a99ba403 |
1432 | or false result of matching the pattern against $_ as the string, |
1433 | which is probably not what you had in mind. |
1434 | |
1435 | =item %s() called too early to check prototype |
1436 | |
1437 | (W) You've called a function that has a prototype before the parser saw a |
1438 | definition or declaration for it, and Perl could not check that the call |
1439 | conforms to the prototype. You need to either add an early prototype |
1440 | declaration for the subroutine in question, or move the subroutine |
1441 | definition ahead of the call to get proper prototype checking. Alternatively, |
1442 | if you are certain that you're calling the function correctly, you may put |
1443 | an ampersand before the name to avoid the warning. See L<perlsub>. |
1444 | |
09bef843 |
1445 | =item %s package attribute may clash with future reserved word: %s |
1446 | |
1447 | (W) A lowercase attribute name was used that had a package-specific handler. |
1448 | That name might have a meaning to Perl itself some day, even though it |
1449 | doesn't yet. Perhaps you should use a mixed-case attribute name, instead. |
1450 | See L<attributes>. |
1451 | |
a99ba403 |
1452 | =item (in cleanup) %s |
6b121555 |
1453 | |
a99ba403 |
1454 | (W) This prefix usually indicates that a DESTROY() method raised |
1455 | the indicated exception. Since destructors are usually called by |
1456 | the system at arbitrary points during execution, and often a vast |
1457 | number of times, the warning is issued only once for any number |
1458 | of failures that would otherwise result in the same message being |
1459 | repeated. |
1460 | |
1461 | Failure of user callbacks dispatched using the C<G_KEEPERR> flag |
1462 | could also result in this warning. See L<perlcall/G_KEEPERR>. |
1463 | |
1464 | =item <> should be quotes |
1465 | |
1466 | (F) You wrote C<require E<lt>fileE<gt>> when you should have written |
1467 | C<require 'file'>. |
1468 | |
1469 | =item Attempt to join self |
1470 | |
1471 | (F) You tried to join a thread from within itself, which is an |
1472 | impossible task. You may be joining the wrong thread, or you may |
1473 | need to move the join() to some other thread. |
1474 | |
1475 | =item Bad evalled substitution pattern |
1476 | |
1477 | (F) You've used the /e switch to evaluate the replacement for a |
1478 | substitution, but perl found a syntax error in the code to evaluate, |
1479 | most likely an unexpected right brace '}'. |
1480 | |
1481 | =item Bad realloc() ignored |
1482 | |
1483 | (S) An internal routine called realloc() on something that had never been |
1484 | malloc()ed in the first place. Mandatory, but can be disabled by |
1485 | setting environment variable C<PERL_BADFREE> to 1. |
1486 | |
1487 | =item Binary number > 0b11111111111111111111111111111111 non-portable |
1488 | |
1489 | (W) The binary number you specified is larger than 2**32-1 |
1490 | (4294967295) and therefore non-portable between systems. See |
1491 | L<perlport> for more on portability concerns. |
1492 | |
1493 | =item Bit vector size > 32 non-portable |
1494 | |
1495 | (W) Using bit vector sizes larger than 32 is non-portable. |
1496 | |
1497 | =item Buffer overflow in prime_env_iter: %s |
1498 | |
1499 | (W) A warning peculiar to VMS. While Perl was preparing to iterate over |
1500 | %ENV, it encountered a logical name or symbol definition which was too long, |
1501 | so it was truncated to the string shown. |
1502 | |
1503 | =item Can't check filesystem of script "%s" |
1504 | |
1505 | (P) For some reason you can't check the filesystem of the script for nosuid. |
1506 | |
1507 | =item Can't modify non-lvalue subroutine call |
1508 | |
437784d6 |
1509 | (F) Subroutines meant to be used in lvalue context should be declared as |
1510 | such, see L<perlsub/"Lvalue subroutines">. |
a99ba403 |
1511 | |
1512 | =item Can't read CRTL environ |
1513 | |
1514 | (S) A warning peculiar to VMS. Perl tried to read an element of %ENV |
1515 | from the CRTL's internal environment array and discovered the array was |
1516 | missing. You need to figure out where your CRTL misplaced its environ |
1517 | or define F<PERL_ENV_TABLES> (see L<perlvms>) so that environ is not searched. |
1518 | |
1519 | =item Can't remove %s: %s, skipping file |
1520 | |
1521 | (S) You requested an inplace edit without creating a backup file. Perl |
1522 | was unable to remove the original file to replace it with the modified |
1523 | file. The file was left unmodified. |
1524 | |
1525 | =item Can't return %s from lvalue subroutine |
1526 | |
1527 | (F) Perl detected an attempt to return illegal lvalues (such |
1528 | as temporary or readonly values) from a subroutine used as an lvalue. |
1529 | This is not allowed. |
1530 | |
1531 | =item Can't weaken a nonreference |
1532 | |
1533 | (F) You attempted to weaken something that was not a reference. Only |
1534 | references can be weakened. |
1535 | |
1536 | =item Character class [:%s:] unknown |
1537 | |
1538 | (F) The class in the character class [: :] syntax is unknown. |
437784d6 |
1539 | See L<perlre>. |
a99ba403 |
1540 | |
1541 | =item Character class syntax [%s] belongs inside character classes |
1542 | |
1543 | (W) The character class constructs [: :], [= =], and [. .] go |
1544 | I<inside> character classes, the [] are part of the construct, |
437784d6 |
1545 | for example: /[012[:alpha:]345]/. Note that [= =] and [. .] |
1546 | are not currently implemented; they are simply placeholders for |
1547 | future extensions. |
a99ba403 |
1548 | |
1549 | =item Constant is not %s reference |
1550 | |
1551 | (F) A constant value (perhaps declared using the C<use constant> pragma) |
1552 | is being dereferenced, but it amounts to the wrong type of reference. The |
1553 | message indicates the type of reference that was expected. This usually |
1554 | indicates a syntax error in dereferencing the constant value. |
1555 | See L<perlsub/"Constant Functions"> and L<constant>. |
1556 | |
1557 | =item constant(%s): %%^H is not localized |
1558 | |
1559 | (F) When setting compile-time-lexicalized hash %^H one should set the |
1560 | corresponding bit of $^H as well. |
1561 | |
1562 | =item constant(%s): %s |
1563 | |
1564 | (F) Compile-time-substitutions (such as overloaded constants and |
1565 | character names) were not correctly set up. |
1566 | |
1567 | =item defined(@array) is deprecated |
1568 | |
1569 | (D) defined() is not usually useful on arrays because it checks for an |
1570 | undefined I<scalar> value. If you want to see if the array is empty, |
1571 | just use C<if (@array) { # not empty }> for example. |
1572 | |
1573 | =item defined(%hash) is deprecated |
1574 | |
1575 | (D) defined() is not usually useful on hashes because it checks for an |
1576 | undefined I<scalar> value. If you want to see if the hash is empty, |
1577 | just use C<if (%hash) { # not empty }> for example. |
1578 | |
1579 | =item Did not produce a valid header |
1580 | |
1581 | See Server error. |
1582 | |
1583 | =item Document contains no data |
1584 | |
1585 | See Server error. |
1586 | |
1587 | =item entering effective %s failed |
1588 | |
1589 | (F) While under the C<use filetest> pragma, switching the real and |
1590 | effective uids or gids failed. |
6b121555 |
1591 | |
73b437c8 |
1592 | =item false [] range "%s" in regexp |
1593 | |
1594 | (W) A character class range must start and end at a literal character, not |
1595 | another character class like C<\d> or C<[:alpha:]>. The "-" in your false |
1596 | range is interpreted as a literal "-". Consider quoting the "-", "\-". |
1597 | See L<perlre>. |
1598 | |
af8c498a |
1599 | =item Filehandle %s opened only for output |
6b121555 |
1600 | |
af8c498a |
1601 | (W) You tried to read from a filehandle opened only for writing. If you |
437784d6 |
1602 | intended it to be a read/write filehandle, you needed to open it with |
af8c498a |
1603 | "+E<lt>" or "+E<gt>" or "+E<gt>E<gt>" instead of with "E<lt>" or nothing. If |
1604 | you intended only to read from the file, use "E<lt>". See |
1605 | L<perlfunc/open>. |
e02fdbd2 |
1606 | |
a99ba403 |
1607 | =item Hexadecimal number > 0xffffffff non-portable |
1608 | |
1609 | (W) The hexadecimal number you specified is larger than 2**32-1 |
1610 | (4294967295) and therefore non-portable between systems. See |
1611 | L<perlport> for more on portability concerns. |
1612 | |
1613 | =item Ill-formed CRTL environ value "%s" |
1614 | |
1615 | (W) A warning peculiar to VMS. Perl tried to read the CRTL's internal |
1616 | environ array, and encountered an element without the C<=> delimiter |
1617 | used to spearate keys from values. The element is ignored. |
1618 | |
1619 | =item Ill-formed message in prime_env_iter: |%s| |
1620 | |
1621 | (W) A warning peculiar to VMS. Perl tried to read a logical name |
1622 | or CLI symbol definition when preparing to iterate over %ENV, and |
1623 | didn't see the expected delimiter between key and value, so the |
1624 | line was ignored. |
1625 | |
1626 | =item Illegal binary digit %s |
1627 | |
437784d6 |
1628 | (F) You used a digit other than 0 or 1 in a binary number. |
a99ba403 |
1629 | |
1630 | =item Illegal binary digit %s ignored |
1631 | |
1632 | (W) You may have tried to use a digit other than 0 or 1 in a binary number. |
1633 | Interpretation of the binary number stopped before the offending digit. |
1634 | |
1635 | =item Illegal number of bits in vec |
1636 | |
1637 | (F) The number of bits in vec() (the third argument) must be a power of |
1638 | two from 1 to 32 (or 64, if your platform supports that). |
1639 | |
1640 | =item Integer overflow in %s number |
1641 | |
1642 | (W) The hexadecimal, octal or binary number you have specified either |
c6edd1b7 |
1643 | as a literal or as an argument to hex() or oct() is too big for your |
a99ba403 |
1644 | architecture, and has been converted to a floating point number. On a |
1645 | 32-bit architecture the largest hexadecimal, octal or binary number |
1646 | representable without overflow is 0xFFFFFFFF, 037777777777, or |
1647 | 0b11111111111111111111111111111111 respectively. Note that Perl |
1648 | transparently promotes all numbers to a floating point representation |
1649 | internally--subject to loss of precision errors in subsequent |
1650 | operations. |
1651 | |
09bef843 |
1652 | =item Invalid %s attribute: %s |
1653 | |
1654 | The indicated attribute for a subroutine or variable was not recognized |
1655 | by Perl or by a user-supplied handler. See L<attributes>. |
1656 | |
1657 | =item Invalid %s attributes: %s |
1658 | |
1659 | The indicated attributes for a subroutine or variable were not recognized |
1660 | by Perl or by a user-supplied handler. See L<attributes>. |
1661 | |
73b437c8 |
1662 | =item invalid [] range "%s" in regexp |
1663 | |
1664 | The offending range is now explicitly displayed. |
1665 | |
09bef843 |
1666 | =item Invalid separator character %s in attribute list |
1667 | |
1668 | (F) Something other than a comma or whitespace was seen between the |
1669 | elements of an attribute list. If the previous attribute |
1670 | had a parenthesised parameter list, perhaps that list was terminated |
1671 | too soon. See L<attributes>. |
1672 | |
a99ba403 |
1673 | =item Invalid separator character %s in subroutine attribute list |
1674 | |
1675 | (F) Something other than a comma or whitespace was seen between the |
1676 | elements of a subroutine attribute list. If the previous attribute |
1677 | had a parenthesised parameter list, perhaps that list was terminated |
1678 | too soon. |
1679 | |
1680 | =item leaving effective %s failed |
1681 | |
1682 | (F) While under the C<use filetest> pragma, switching the real and |
1683 | effective uids or gids failed. |
1684 | |
1685 | =item Lvalue subs returning %s not implemented yet |
1686 | |
1687 | (F) Due to limitations in the current implementation, array and hash |
1688 | values cannot be returned in subroutines used in lvalue context. |
1689 | See L<perlsub/"Lvalue subroutines">. |
1690 | |
1691 | =item Method %s not permitted |
1692 | |
1693 | See Server error. |
1694 | |
1695 | =item Missing %sbrace%s on \N{} |
1696 | |
1697 | (F) Wrong syntax of character name literal C<\N{charname}> within |
1698 | double-quotish context. |
1699 | |
06eaf0bc |
1700 | =item Missing command in piped open |
1701 | |
1702 | (W) You used the C<open(FH, "| command")> or C<open(FH, "command |")> |
1703 | construction, but the command was missing or blank. |
1704 | |
09bef843 |
1705 | =item Missing name in "my sub" |
1706 | |
1707 | (F) The reserved syntax for lexically scoped subroutines requires that they |
1708 | have a name with which they can be found. |
1709 | |
a99ba403 |
1710 | =item no UTC offset information; assuming local time is UTC |
1711 | |
1712 | (S) A warning peculiar to VMS. Perl was unable to find the local |
1713 | timezone offset, so it's assuming that local system time is equivalent |
1714 | to UTC. If it's not, define the logical name F<SYS$TIMEZONE_DIFFERENTIAL> |
1715 | to translate to the number of seconds which need to be added to UTC to |
1716 | get local time. |
1717 | |
1718 | =item Octal number > 037777777777 non-portable |
1719 | |
1720 | (W) The octal number you specified is larger than 2**32-1 (4294967295) |
1721 | and therefore non-portable between systems. See L<perlport> for more |
1722 | on portability concerns. |
1723 | |
1724 | See also L<perlport> for writing portable code. |
1725 | |
1726 | =item panic: del_backref |
1727 | |
1728 | (P) Failed an internal consistency check while trying to reset a weak |
1729 | reference. |
1730 | |
1731 | =item panic: kid popen errno read |
1732 | |
1733 | (F) forked child returned an incomprehensible message about its errno. |
1734 | |
1735 | =item panic: magic_killbackrefs |
1736 | |
1737 | (P) Failed an internal consistency check while trying to reset all weak |
1738 | references to an object. |
1739 | |
1740 | =item Possible Y2K bug: %s |
1741 | |
1742 | (W) You are concatenating the number 19 with another number, which |
1743 | could be a potential Year 2000 problem. |
1744 | |
1745 | =item Premature end of script headers |
1746 | |
1747 | See Server error. |
1748 | |
1749 | =item realloc() of freed memory ignored |
1750 | |
1751 | (S) An internal routine called realloc() on something that had already |
1752 | been freed. |
1753 | |
1754 | =item Reference is already weak |
1755 | |
1756 | (W) You have attempted to weaken a reference that is already weak. |
1757 | Doing so has no effect. |
1758 | |
1759 | =item setpgrp can't take arguments |
1760 | |
1761 | (F) Your system has the setpgrp() from BSD 4.2, which takes no arguments, |
1762 | unlike POSIX setpgid(), which takes a process ID and process group ID. |
1763 | |
1764 | =item Strange *+?{} on zero-length expression |
1765 | |
1766 | (W) You applied a regular expression quantifier in a place where it |
1767 | makes no sense, such as on a zero-width assertion. |
1768 | Try putting the quantifier inside the assertion instead. For example, |
1769 | the way to match "abc" provided that it is followed by three |
1770 | repetitions of "xyz" is C</abc(?=(?:xyz){3})/>, not C</abc(?=xyz){3}/>. |
1771 | |
1772 | =item switching effective %s is not implemented |
1773 | |
1774 | (F) While under the C<use filetest> pragma, we cannot switch the |
1775 | real and effective uids or gids. |
1776 | |
437784d6 |
1777 | =item This Perl can't reset CRTL environ elements (%s) |
a99ba403 |
1778 | |
1779 | =item This Perl can't set CRTL environ elements (%s=%s) |
1780 | |
1781 | (W) Warnings peculiar to VMS. You tried to change or delete an element |
1782 | of the CRTL's internal environ array, but your copy of Perl wasn't |
1783 | built with a CRTL that contained the setenv() function. You'll need to |
1784 | rebuild Perl with a CRTL that does, or redefine F<PERL_ENV_TABLES> (see |
1785 | L<perlvms>) so that the environ array isn't the target of the change to |
1786 | %ENV which produced the warning. |
1787 | |
1788 | =item Unknown open() mode '%s' |
1789 | |
437784d6 |
1790 | (F) The second argument of 3-argument open() is not among the list |
1791 | of valid modes: C<L<lt>>, C<L<gt>>, C<E<gt>E<gt>>, C<+L<lt>>, |
1792 | C<+L<gt>>, C<+E<gt>E<gt>>, C<-|>, C<|->. |
a99ba403 |
1793 | |
1794 | =item Unknown process %x sent message to prime_env_iter: %s |
1795 | |
1796 | (P) An error peculiar to VMS. Perl was reading values for %ENV before |
1797 | iterating over it, and someone else stuck a message in the stream of |
1798 | data Perl expected. Someone's very confused, or perhaps trying to |
1799 | subvert Perl's population of %ENV for nefarious purposes. |
1800 | |
af8c498a |
1801 | =item Unrecognized escape \\%c passed through |
1802 | |
1803 | (W) You used a backslash-character combination which is not recognized |
1028017a |
1804 | by Perl. The character was understood literally. |
af8c498a |
1805 | |
09bef843 |
1806 | =item Unterminated attribute parameter in attribute list |
1807 | |
1808 | (F) The lexer saw an opening (left) parenthesis character while parsing an |
1809 | attribute list, but the matching closing (right) parenthesis |
1810 | character was not found. You may need to add (or remove) a backslash |
1811 | character to get your parentheses to balance. See L<attributes>. |
1812 | |
1813 | =item Unterminated attribute list |
1814 | |
1815 | (F) The lexer found something other than a simple identifier at the start |
1816 | of an attribute, and it wasn't a semicolon or the start of a |
1817 | block. Perhaps you terminated the parameter list of the previous attribute |
1818 | too soon. See L<attributes>. |
1819 | |
09bef843 |
1820 | =item Unterminated attribute parameter in subroutine attribute list |
1821 | |
1822 | (F) The lexer saw an opening (left) parenthesis character while parsing a |
1823 | subroutine attribute list, but the matching closing (right) parenthesis |
1824 | character was not found. You may need to add (or remove) a backslash |
1825 | character to get your parentheses to balance. |
1826 | |
1827 | =item Unterminated subroutine attribute list |
1828 | |
1829 | (F) The lexer found something other than a simple identifier at the start |
1830 | of a subroutine attribute, and it wasn't a semicolon or the start of a |
1831 | block. Perhaps you terminated the parameter list of the previous attribute |
1832 | too soon. |
1833 | |
a99ba403 |
1834 | =item Value of CLI symbol "%s" too long |
eb6e2d6f |
1835 | |
a99ba403 |
1836 | (W) A warning peculiar to VMS. Perl tried to read the value of an %ENV |
1837 | element from a CLI symbol table, and found a resultant string longer |
1838 | than 1024 characters. The return value has been truncated to 1024 |
1839 | characters. |
eb6e2d6f |
1840 | |
a99ba403 |
1841 | =item Version number must be a constant number |
ba8251e8 |
1842 | |
a99ba403 |
1843 | (P) The attempt to translate a C<use Module n.n LIST> statement into |
1844 | its equivalent C<BEGIN> block found an internal inconsistency with |
1845 | the version number. |
1846 | |
1847 | =back |
27806c82 |
1848 | |
a5222a85 |
1849 | =head1 Obsolete Diagnostics |
3175b8cd |
1850 | |
a99ba403 |
1851 | =over 4 |
1852 | |
1853 | =item Character class syntax [: :] is reserved for future extensions |
1854 | |
1855 | (W) Within regular expression character classes ([]) the syntax beginning |
1856 | with "[:" and ending with ":]" is reserved for future extensions. |
1857 | If you need to represent those character sequences inside a regular |
1858 | expression character class, just quote the square brackets with the |
1859 | backslash: "\[:" and ":\]". |
1860 | |
1861 | =item Ill-formed logical name |%s| in prime_env_iter |
1862 | |
1863 | (W) A warning peculiar to VMS. A logical name was encountered when preparing |
1864 | to iterate over %ENV which violates the syntactic rules governing logical |
1865 | names. Because it cannot be translated normally, it is skipped, and will not |
1866 | appear in %ENV. This may be a benign occurrence, as some software packages |
1867 | might directly modify logical name tables and introduce nonstandard names, |
1868 | or it may indicate that a logical name table has been corrupted. |
1869 | |
1870 | =item regexp too big |
1871 | |
1872 | (F) The current implementation of regular expressions uses shorts as |
1873 | address offsets within a string. Unfortunately this means that if |
1874 | the regular expression compiles to longer than 32767, it'll blow up. |
1875 | Usually when you want a regular expression this big, there is a better |
1876 | way to do it with multiple statements. See L<perlre>. |
1877 | |
1878 | =item Use of "$$<digit>" to mean "${$}<digit>" is deprecated |
1879 | |
1880 | (D) Perl versions before 5.004 misinterpreted any type marker followed |
1881 | by "$" and a digit. For example, "$$0" was incorrectly taken to mean |
1882 | "${$}0" instead of "${$0}". This bug is (mostly) fixed in Perl 5.004. |
1883 | |
1884 | However, the developers of Perl 5.004 could not fix this bug completely, |
1885 | because at least two widely-used modules depend on the old meaning of |
1886 | "$$0" in a string. So Perl 5.004 still interprets "$$<digit>" in the |
1887 | old (broken) way inside strings; but it generates this message as a |
1888 | warning. And in Perl 5.005, this special treatment will cease. |
1889 | |
1890 | =back |
3175b8cd |
1891 | |
ba8251e8 |
1892 | =head1 BUGS |
1893 | |
437784d6 |
1894 | If you find what you think is a bug, you might check the |
14218588 |
1895 | articles recently posted to the comp.lang.perl.misc newsgroup. |
ba8251e8 |
1896 | There may also be information at http://www.perl.com/perl/, the Perl |
1897 | Home Page. |
1898 | |
1899 | If you believe you have an unreported bug, please run the B<perlbug> |
14218588 |
1900 | program included with your release. Make sure to trim your bug down |
ba8251e8 |
1901 | to a tiny but sufficient test case. Your bug report, along with the |
14218588 |
1902 | output of C<perl -V>, will be sent off to perlbug@perl.com to be |
ba8251e8 |
1903 | analysed by the Perl porting team. |
1904 | |
1905 | =head1 SEE ALSO |
1906 | |
1907 | The F<Changes> file for exhaustive details on what changed. |
1908 | |
1909 | The F<INSTALL> file for how to build Perl. |
1910 | |
1911 | The F<README> file for general stuff. |
1912 | |
1913 | The F<Artistic> and F<Copying> files for copyright information. |
1914 | |
1915 | =head1 HISTORY |
1916 | |
a5222a85 |
1917 | Written by Gurusamy Sarathy <F<gsar@activestate.com>>, with many |
1918 | contributions from The Perl Porters. |
ba8251e8 |
1919 | |
1920 | Send omissions or corrections to <F<perlbug@perl.com>>. |
1921 | |
1922 | =cut |