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1 | =head1 NAME |
2 | |
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3 | perldelta - what's new for perl5.004 |
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4 | |
5 | =head1 DESCRIPTION |
6 | |
7 | This document describes differences between the 5.003 release (as |
8 | documented in I<Programming Perl>, second edition--the Camel Book) and |
9 | this one. |
10 | |
11 | =head1 Supported Environments |
12 | |
13 | Perl5.004 builds out of the box on Unix, Plan9, LynxOS, VMS, OS/2, |
14 | QNX, and AmigaOS. |
15 | |
16 | =head1 Core Changes |
17 | |
18 | Most importantly, many bugs were fixed. See the F<Changes> |
19 | file in the distribution for details. |
20 | |
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21 | =head2 Compilation option: Binary compatibility with 5.003 |
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22 | |
23 | There is a new Configure question that asks if you want to maintain |
24 | binary compatibility with Perl 5.003. If you choose binary |
25 | compatibility, you do not have to recompile your extensions, but you |
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26 | might have symbol conflicts if you embed Perl in another application, |
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27 | just as in the 5.003 release. By default, binary compatibility |
28 | is preserved at the expense of symbol table pollution. |
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29 | |
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30 | =head2 $PERL5OPT environment variable |
31 | |
32 | You may now put Perl options in the $PERL5OPT environment variable. |
33 | Unless Perl is running with taint checks, it will interpret this |
34 | variable as if its contents had appeared on a "#!perl" line at the |
35 | beginning of your script, except that hyphens are optional. PERL5OPT |
36 | may only be used to set the following switches: B<-[DIMUdmw]>. |
37 | |
38 | =head2 More precise warnings |
39 | |
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40 | If you removed the B<-w> option from your Perl 5.003 scripts because it |
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41 | made Perl too verbose, we recommend that you try putting it back when |
42 | you upgrade to Perl 5.004. Each new perl version tends to remove some |
43 | undesirable warnings, while adding new warnings that may catch bugs in |
44 | your scripts. |
45 | |
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46 | =head2 Deprecated: Inherited C<AUTOLOAD> for non-methods |
47 | |
48 | Before Perl 5.004, C<AUTOLOAD> functions were looked up as methods |
49 | (using the C<@ISA> hierarchy), even when the function to be autoloaded |
50 | was called as a plain function (e.g. C<Foo::bar()>), not a method |
51 | (e.g. C<Foo->bar()> or C<$obj->bar()>). |
52 | |
53 | Perl 5.005 will use method lookup only for methods' C<AUTOLOAD>s. |
54 | However, there is a significant base of existing code that may be using |
55 | the old behavior. So, as an interim step, Perl 5.004 issues an optional |
56 | warning when a non-method uses an inherited C<AUTOLOAD>. |
57 | |
58 | The simple rule is: Inheritance will not work when autoloading |
59 | non-methods. The simple fix for old code is: In any module that used to |
60 | depend on inheriting C<AUTOLOAD> for non-methods from a base class named |
61 | C<BaseClass>, execute C<*AUTOLOAD = \&BaseClass::AUTOLOAD> during startup. |
62 | |
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63 | =head2 Subroutine arguments created only when they're modified |
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64 | |
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65 | In Perl 5.004, nonexistent array and hash elements used as subroutine |
66 | parameters are brought into existence only if they are actually |
67 | assigned to (via C<@_>). |
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68 | |
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69 | Earlier versions of Perl vary in their handling of such arguments. |
70 | Perl versions 5.002 and 5.003 always brought them into existence. |
71 | Perl versions 5.000, 5.001, and 5.002 brought them into existence only |
72 | if they were not the first argument (which was almost certainly a |
73 | bug). Earlier versions of Perl never brought them into existence. |
74 | |
75 | For example, given this code: |
76 | |
77 | undef @a; undef %a; |
78 | sub show { print $_[0] }; |
79 | sub change { $_[0]++ }; |
80 | show($a[2]); |
81 | change($a{b}); |
82 | |
83 | After this code executes in Perl 5.004, $a{b} exists but $a[2] does |
84 | not. In Perl 5.002 and 5.003, both $a{b} and $a[2] would have existed |
85 | (but $a[2]'s value would have been undefined). |
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86 | |
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87 | =head2 Fixed parsing of $$<digit>, &$<digit>, etc. |
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88 | |
89 | A bug in previous versions of Perl 5.0 prevented proper parsing of |
90 | numeric special variables as symbolic references. That bug has been |
91 | fixed. As a result, the string "$$0" is no longer equivalent to |
92 | C<$$."0">, but rather to C<${$0}>. To get the old behavior, change |
93 | "$$" followed by a digit to "${$}". |
94 | |
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95 | =head2 No resetting of $. on implicit close |
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96 | |
97 | The documentation for Perl 5.0 has always stated that C<$.> is I<not> |
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98 | reset when an already-open file handle is reopened with no intervening |
99 | call to C<close>. Due to a bug, perl versions 5.000 through 5.003 |
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100 | I<did> reset C<$.> under that circumstance; Perl 5.004 does not. |
101 | |
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102 | =head2 C<wantarray> may return undef |
103 | |
104 | The C<wantarray> operator returns true if a subroutine is expected to |
105 | return a list, and false otherwise. In Perl 5.004, C<wantarray> can |
106 | also return the undefined value if a subroutine's return value will |
107 | not be used at all, which allows subroutines to avoid a time-consuming |
108 | calculation of a return value if it isn't going to be used. |
109 | |
110 | =head2 Changes to tainting checks |
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111 | |
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112 | A bug in previous versions may have failed to detect some insecure |
113 | conditions when taint checks are turned on. (Taint checks are used |
114 | in setuid or setgid scripts, or when explicitly turned on with the |
115 | C<-T> invocation option.) Although it's unlikely, this may cause a |
116 | previously-working script to now fail -- which should be construed |
117 | as a blessing, since that indicates a potentially-serious security |
118 | hole was just plugged. |
119 | |
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120 | =head2 New Opcode module and revised Safe module |
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121 | |
122 | A new Opcode module supports the creation, manipulation and |
123 | application of opcode masks. The revised Safe module has a new API |
124 | and is implemented using the new Opcode module. Please read the new |
125 | Opcode and Safe documentation. |
126 | |
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127 | =head2 Embedding improvements |
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128 | |
129 | In older versions of Perl it was not possible to create more than one |
130 | Perl interpreter instance inside a single process without leaking like a |
131 | sieve and/or crashing. The bugs that caused this behavior have all been |
132 | fixed. However, you still must take care when embedding Perl in a C |
133 | program. See the updated perlembed manpage for tips on how to manage |
134 | your interpreters. |
135 | |
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136 | =head2 Internal change: FileHandle class based on IO::* classes |
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137 | |
138 | File handles are now stored internally as type IO::Handle. The |
139 | FileHandle module is still supported for backwards compatibility, but |
140 | it is now merely a front end to the IO::* modules -- specifically, |
141 | IO::Handle, IO::Seekable, and IO::File. We suggest, but do not |
142 | require, that you use the IO::* modules in new code. |
143 | |
144 | In harmony with this change, C<*GLOB{FILEHANDLE}> is now a |
145 | backward-compatible synonym for C<*STDOUT{IO}>. |
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146 | |
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147 | =head2 Internal change: PerlIO abstraction interface |
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148 | |
149 | It is now possible to build Perl with AT&T's sfio IO package |
150 | instead of stdio. See L<perlapio> for more details, and |
151 | the F<INSTALL> file for how to use it. |
152 | |
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153 | =head2 New and changed builtin variables |
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154 | |
155 | =over |
156 | |
157 | =item $^E |
158 | |
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159 | Extended error message on some platforms. (Also known as |
160 | $EXTENDED_OS_ERROR if you C<use English>). |
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161 | |
162 | =item $^H |
163 | |
164 | The current set of syntax checks enabled by C<use strict>. See the |
165 | documentation of C<strict> for more details. Not actually new, but |
166 | newly documented. |
167 | Because it is intended for internal use by Perl core components, |
168 | there is no C<use English> long name for this variable. |
169 | |
170 | =item $^M |
171 | |
172 | By default, running out of memory it is not trappable. However, if |
173 | compiled for this, Perl may use the contents of C<$^M> as an emergency |
174 | pool after die()ing with this message. Suppose that your Perl were |
175 | compiled with -DEMERGENCY_SBRK and used Perl's malloc. Then |
176 | |
177 | $^M = 'a' x (1<<16); |
178 | |
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179 | would allocate a 64K buffer for use when in emergency. |
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180 | See the F<INSTALL> file for information on how to enable this option. |
181 | As a disincentive to casual use of this advanced feature, |
182 | there is no C<use English> long name for this variable. |
183 | |
184 | =back |
185 | |
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186 | =head2 New and changed builtin functions |
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187 | |
188 | =over |
189 | |
190 | =item delete on slices |
191 | |
192 | This now works. (e.g. C<delete @ENV{'PATH', 'MANPATH'}>) |
193 | |
194 | =item flock |
195 | |
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196 | is now supported on more platforms, prefers fcntl to lockf when |
197 | emulating, and always flushes before (un)locking. |
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198 | |
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199 | =item printf and sprintf |
200 | |
201 | now support "%i" as a synonym for "%d", and the "h" modifier. |
202 | So "%hi" means "short integer in decimal", and "%ho" means |
203 | "unsigned short integer as octal". |
204 | |
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205 | =item keys as an lvalue |
206 | |
207 | As an lvalue, C<keys> allows you to increase the number of hash buckets |
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208 | allocated for the given hash. This can gain you a measure of efficiency if |
209 | you know the hash is going to get big. (This is similar to pre-extending |
210 | an array by assigning a larger number to $#array.) If you say |
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211 | |
212 | keys %hash = 200; |
213 | |
214 | then C<%hash> will have at least 200 buckets allocated for it. These |
215 | buckets will be retained even if you do C<%hash = ()>; use C<undef |
216 | %hash> if you want to free the storage while C<%hash> is still in scope. |
217 | You can't shrink the number of buckets allocated for the hash using |
218 | C<keys> in this way (but you needn't worry about doing this by accident, |
219 | as trying has no effect). |
220 | |
221 | =item my() in Control Structures |
222 | |
223 | You can now use my() (with or without the parentheses) in the control |
224 | expressions of control structures such as: |
225 | |
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226 | while (defined(my $line = <>)) { |
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227 | $line = lc $line; |
228 | } continue { |
229 | print $line; |
230 | } |
231 | |
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232 | if ((my $answer = <STDIN>) =~ /^y(es)?$/i) { |
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233 | user_agrees(); |
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234 | } elsif ($answer =~ /^n(o)?$/i) { |
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235 | user_disagrees(); |
236 | } else { |
237 | chomp $answer; |
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238 | die "`$answer' is neither `yes' nor `no'"; |
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239 | } |
240 | |
241 | Also, you can declare a foreach loop control variable as lexical by |
242 | preceding it with the word "my". For example, in: |
243 | |
244 | foreach my $i (1, 2, 3) { |
245 | some_function(); |
246 | } |
247 | |
248 | $i is a lexical variable, and the scope of $i extends to the end of |
249 | the loop, but not beyond it. |
250 | |
251 | Note that you still cannot use my() on global punctuation variables |
252 | such as $_ and the like. |
253 | |
254 | =item unpack() and pack() |
255 | |
256 | A new format 'w' represents a BER compressed integer (as defined in |
257 | ASN.1). Its format is a sequence of one or more bytes, each of which |
258 | provides seven bits of the total value, with the most significant |
259 | first. Bit eight of each byte is set, except for the last byte, in |
260 | which bit eight is clear. |
261 | |
262 | =item use VERSION |
263 | |
264 | If the first argument to C<use> is a number, it is treated as a version |
265 | number instead of a module name. If the version of the Perl interpreter |
266 | is less than VERSION, then an error message is printed and Perl exits |
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267 | immediately. Because C<use> occurs at compile time, this check happens |
268 | immediately during the compilation process, unlike C<require VERSION>, |
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269 | which waits until runtime for the check. This is often useful if you |
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270 | need to check the current Perl version before C<use>ing library modules |
271 | which have changed in incompatible ways from older versions of Perl. |
272 | (We try not to do this more than we have to.) |
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273 | |
274 | =item use Module VERSION LIST |
275 | |
276 | If the VERSION argument is present between Module and LIST, then the |
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277 | C<use> will call the VERSION method in class Module with the given |
278 | version as an argument. The default VERSION method, inherited from |
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279 | the UNIVERSAL class, croaks if the given version is larger than the |
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280 | value of the variable $Module::VERSION. (Note that there is not a |
281 | comma after VERSION!) |
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282 | |
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283 | This version-checking mechanism is similar to the one currently used |
284 | in the Exporter module, but it is faster and can be used with modules |
285 | that don't use the Exporter. It is the recommended method for new |
286 | code. |
287 | |
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288 | =item prototype(FUNCTION) |
289 | |
290 | Returns the prototype of a function as a string (or C<undef> if the |
291 | function has no prototype). FUNCTION is a reference to or the name of the |
292 | function whose prototype you want to retrieve. |
293 | (Not actually new; just never documented before.) |
294 | |
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295 | =item srand |
296 | |
297 | The default seed for C<srand>, which used to be C<time>, has been changed. |
298 | Now it's a heady mix of difficult-to-predict system-dependent values, |
299 | which should be sufficient for most everyday purposes. |
300 | |
301 | Previous to version 5.004, calling C<rand> without first calling C<srand> |
302 | would yield the same sequence of random numbers on most or all machines. |
303 | Now, when perl sees that you're calling C<rand> and haven't yet called |
304 | C<srand>, it calls C<srand> with the default seed. You should still call |
305 | C<srand> manually if your code might ever be run on a pre-5.004 system, |
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306 | of course, or if you want a seed other than the default. |
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307 | |
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308 | =item $_ as Default |
309 | |
310 | Functions documented in the Camel to default to $_ now in |
311 | fact do, and all those that do are so documented in L<perlfunc>. |
312 | |
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313 | =item C<m//g> does not trigger a pos() reset on failure |
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314 | |
315 | The C<m//g> match iteration construct used to reset the iteration |
316 | when it failed to match (so that the next C<m//g> match would start at |
317 | the beginning of the string). You now have to explicitly do a |
318 | C<pos $str = 0;> to reset the "last match" position, or modify the |
319 | string in some way. This change makes it practical to chain C<m//g> |
320 | matches together in conjunction with ordinary matches using the C<\G> |
321 | zero-width assertion. See L<perlop> and L<perlre>. |
322 | |
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323 | =item C<m//x> ignores whitespace before ?*+{} |
324 | |
325 | The C<m//x> construct has always been intended to ignore all unescaped |
326 | whitespace. However, before Perl 5.004, whitespace had the effect of |
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327 | escaping repeat modifiers like "*" or "?"; for example, C</a *b/x> was |
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328 | (mis)interpreted as C</a\*b/x>. This bug has been fixed in 5.004. |
329 | |
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330 | =item nested C<sub{}> closures work now |
331 | |
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332 | Prior to the 5.004 release, nested anonymous functions didn't work |
333 | right. They do now. |
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334 | |
335 | =item formats work right on changing lexicals |
336 | |
337 | Just like anonymous functions that contain lexical variables |
338 | that change (like a lexical index variable for a C<foreach> loop), |
339 | formats now work properly. For example, this silently failed |
340 | before, and is fine now: |
341 | |
342 | my $i; |
343 | foreach $i ( 1 .. 10 ) { |
344 | format = |
345 | my i is @# |
346 | $i |
347 | . |
348 | write; |
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349 | } |
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350 | |
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351 | =back |
352 | |
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353 | =head2 New builtin methods |
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354 | |
355 | The C<UNIVERSAL> package automatically contains the following methods that |
356 | are inherited by all other classes: |
357 | |
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358 | =over |
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359 | |
360 | =item isa(CLASS) |
361 | |
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362 | C<isa> returns I<true> if its object is blessed into a subclass of C<CLASS> |
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363 | |
364 | C<isa> is also exportable and can be called as a sub with two arguments. This |
365 | allows the ability to check what a reference points to. Example: |
366 | |
367 | use UNIVERSAL qw(isa); |
368 | |
369 | if(isa($ref, 'ARRAY')) { |
370 | ... |
371 | } |
372 | |
373 | =item can(METHOD) |
374 | |
375 | C<can> checks to see if its object has a method called C<METHOD>, |
376 | if it does then a reference to the sub is returned; if it does not then |
377 | I<undef> is returned. |
378 | |
379 | =item VERSION( [NEED] ) |
380 | |
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381 | C<VERSION> returns the version number of the class (package). If the |
382 | NEED argument is given then it will check that the current version (as |
383 | defined by the $VERSION variable in the given package) not less than |
384 | NEED; it will die if this is not the case. This method is normally |
385 | called as a class method. This method is called automatically by the |
386 | C<VERSION> form of C<use>. |
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387 | |
388 | use A 1.2 qw(some imported subs); |
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389 | # implies: |
390 | A->VERSION(1.2); |
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391 | |
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392 | =back |
393 | |
394 | B<NOTE:> C<can> directly uses Perl's internal code for method lookup, and |
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395 | C<isa> uses a very similar method and caching strategy. This may cause |
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396 | strange effects if the Perl code dynamically changes @ISA in any package. |
397 | |
398 | You may add other methods to the UNIVERSAL class via Perl or XS code. |
399 | You do not need to C<use UNIVERSAL> in order to make these methods |
400 | available to your program. This is necessary only if you wish to |
401 | have C<isa> available as a plain subroutine in the current package. |
402 | |
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403 | =head2 TIEHANDLE now supported |
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404 | |
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405 | See L<perltie> for other kinds of tie()s. |
406 | |
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407 | =over |
408 | |
409 | =item TIEHANDLE classname, LIST |
410 | |
411 | This is the constructor for the class. That means it is expected to |
412 | return an object of some sort. The reference can be used to |
413 | hold some internal information. |
414 | |
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415 | sub TIEHANDLE { |
416 | print "<shout>\n"; |
417 | my $i; |
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418 | return bless \$i, shift; |
419 | } |
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420 | |
421 | =item PRINT this, LIST |
422 | |
423 | This method will be triggered every time the tied handle is printed to. |
424 | Beyond its self reference it also expects the list that was passed to |
425 | the print function. |
426 | |
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427 | sub PRINT { |
428 | $r = shift; |
429 | $$r++; |
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430 | return print join( $, => map {uc} @_), $\; |
431 | } |
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432 | |
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433 | =item READ this LIST |
434 | |
435 | This method will be called when the handle is read from via the C<read> |
436 | or C<sysread> functions. |
437 | |
438 | sub READ { |
439 | $r = shift; |
440 | my($buf,$len,$offset) = @_; |
441 | print "READ called, \$buf=$buf, \$len=$len, \$offset=$offset"; |
442 | } |
443 | |
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444 | =item READLINE this |
445 | |
446 | This method will be called when the handle is read from. The method |
447 | should return undef when there is no more data. |
448 | |
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449 | sub READLINE { |
450 | $r = shift; |
451 | return "PRINT called $$r times\n" |
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452 | } |
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453 | |
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454 | =item GETC this |
455 | |
456 | This method will be called when the C<getc> function is called. |
457 | |
458 | sub GETC { print "Don't GETC, Get Perl"; return "a"; } |
459 | |
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460 | =item DESTROY this |
461 | |
462 | As with the other types of ties, this method will be called when the |
463 | tied handle is about to be destroyed. This is useful for debugging and |
464 | possibly for cleaning up. |
465 | |
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466 | sub DESTROY { |
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467 | print "</shout>\n"; |
468 | } |
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469 | |
470 | =back |
471 | |
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472 | =head2 Malloc enhancements |
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473 | |
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474 | Four new compilation flags are recognized by malloc.c. (They have no |
475 | effect if perl is compiled with system malloc().) |
476 | |
477 | =over |
478 | |
479 | =item -DDEBUGGING_MSTATS |
480 | |
481 | If perl is compiled with C<DEBUGGING_MSTATS> defined, you can print |
482 | memory statistics at runtime by running Perl thusly: |
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483 | |
484 | env PERL_DEBUG_MSTATS=2 perl your_script_here |
485 | |
486 | The value of 2 means to print statistics after compilation and on |
487 | exit; with a value of 1, the statistics ares printed only on exit. |
488 | (If you want the statistics at an arbitrary time, you'll need to |
489 | install the optional module Devel::Peek.) |
490 | |
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491 | =item -DEMERGENCY_SBRK |
492 | |
493 | If this macro is defined, running out of memory need not be a fatal |
494 | error: a memory pool can allocated by assigning to the special |
495 | variable C<$^M>. See L<"$^M">. |
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496 | |
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497 | =item -DPACK_MALLOC |
498 | |
499 | Perl memory allocation is by bucket with sizes close to powers of two. |
500 | Because of these malloc overhead may be big, especially for data of |
501 | size exactly a power of two. If C<PACK_MALLOC> is defined, perl uses |
502 | a slightly different algorithm for small allocations (up to 64 bytes |
503 | long), which makes it possible to have overhead down to 1 byte for |
504 | allocations which are powers of two (and appear quite often). |
505 | |
506 | Expected memory savings (with 8-byte alignment in C<alignbytes>) is |
507 | about 20% for typical Perl usage. Expected slowdown due to additional |
508 | malloc overhead is in fractions of a percent (hard to measure, because |
509 | of the effect of saved memory on speed). |
510 | |
511 | =item -DTWO_POT_OPTIMIZE |
512 | |
513 | Similarly to C<PACK_MALLOC>, this macro improves allocations of data |
514 | with size close to a power of two; but this works for big allocations |
515 | (starting with 16K by default). Such allocations are typical for big |
516 | hashes and special-purpose scripts, especially image processing. |
517 | |
518 | On recent systems, the fact that perl requires 2M from system for 1M |
519 | allocation will not affect speed of execution, since the tail of such |
520 | a chunk is not going to be touched (and thus will not require real |
521 | memory). However, it may result in a premature out-of-memory error. |
522 | So if you will be manipulating very large blocks with sizes close to |
523 | powers of two, it would be wise to define this macro. |
524 | |
525 | Expected saving of memory is 0-100% (100% in applications which |
526 | require most memory in such 2**n chunks); expected slowdown is |
527 | negligible. |
528 | |
529 | =back |
530 | |
54310121 |
531 | =head2 Miscellaneous efficiency enhancements |
774d564b |
532 | |
533 | Functions that have an empty prototype and that do nothing but return |
534 | a fixed value are now inlined (e.g. C<sub PI () { 3.14159 }>). |
535 | |
aa689395 |
536 | Each unique hash key is only allocated once, no matter how many hashes |
537 | have an entry with that key. So even if you have 100 copies of the |
68dc0745 |
538 | same hash, the hash keys never have to be reallocated. |
aa689395 |
539 | |
5f05dabc |
540 | =head1 Pragmata |
541 | |
54310121 |
542 | Six new pragmatic modules exist: |
5f05dabc |
543 | |
544 | =over |
545 | |
54310121 |
546 | =item use autouse MODULE => qw(sub1 sub2 sub3) |
547 | |
548 | Defers C<require MODULE> until someone calls one of the specified |
549 | subroutines (which must be exported by MODULE). This pragma should be |
550 | used with caution, and only when necessary. |
551 | |
5f05dabc |
552 | =item use blib |
553 | |
774d564b |
554 | =item use blib 'dir' |
555 | |
5f05dabc |
556 | Looks for MakeMaker-like I<'blib'> directory structure starting in |
557 | I<dir> (or current directory) and working back up to five levels of |
558 | parent directories. |
559 | |
560 | Intended for use on command line with B<-M> option as a way of testing |
561 | arbitrary scripts against an uninstalled version of a package. |
562 | |
54310121 |
563 | =item use constant NAME => VALUE |
564 | |
565 | Provides a convenient interface for creating compile-time constants, |
566 | See L<perlsub/"Constant Functions">. |
567 | |
5f05dabc |
568 | =item use locale |
569 | |
570 | Tells the compiler to enable (or disable) the use of POSIX locales for |
54310121 |
571 | builtin operations. |
5f05dabc |
572 | |
573 | When C<use locale> is in effect, the current LC_CTYPE locale is used |
574 | for regular expressions and case mapping; LC_COLLATE for string |
575 | ordering; and LC_NUMERIC for numeric formating in printf and sprintf |
576 | (but B<not> in print). LC_NUMERIC is always used in write, since |
577 | lexical scoping of formats is problematic at best. |
578 | |
579 | Each C<use locale> or C<no locale> affects statements to the end of |
580 | the enclosing BLOCK or, if not inside a BLOCK, to the end of the |
581 | current file. Locales can be switched and queried with |
582 | POSIX::setlocale(). |
583 | |
584 | See L<perllocale> for more information. |
585 | |
586 | =item use ops |
587 | |
7cfe7857 |
588 | Disable unsafe opcodes, or any named opcodes, when compiling Perl code. |
5f05dabc |
589 | |
ff0cee69 |
590 | =item use vmsish |
591 | |
592 | Enable VMS-specific language features. Currently, there are three |
aa689395 |
593 | VMS-specific features available: 'status', which makes C<$?> and |
ff0cee69 |
594 | C<system> return genuine VMS status values instead of emulating POSIX; |
595 | 'exit', which makes C<exit> take a genuine VMS status value instead of |
596 | assuming that C<exit 1> is an error; and 'time', which makes all times |
597 | relative to the local time zone, in the VMS tradition. |
598 | |
5f05dabc |
599 | =back |
600 | |
601 | =head1 Modules |
602 | |
54310121 |
603 | =head2 Installation directories |
f86702cc |
604 | |
605 | The I<installperl> script now places the Perl source files for |
606 | extensions in the architecture-specific library directory, which is |
607 | where the shared libraries for extensions have always been. This |
608 | change is intended to allow administrators to keep the Perl 5.004 |
609 | library directory unchanged from a previous version, without running |
610 | the risk of binary incompatibility between extensions' Perl source and |
611 | shared libraries. |
612 | |
54310121 |
613 | =head2 Module information summary |
5f05dabc |
614 | |
774d564b |
615 | Brand new modules, arranged by topic rather than strictly |
616 | alphabetically: |
617 | |
618 | CPAN interface to Comprehensive Perl Archive Network |
619 | CPAN::FirstTime create a CPAN configuration file |
620 | CPAN::Nox run CPAN while avoiding compiled extensions |
5f05dabc |
621 | |
622 | IO.pm Top-level interface to IO::* classes |
623 | IO/File.pm IO::File extension Perl module |
624 | IO/Handle.pm IO::Handle extension Perl module |
625 | IO/Pipe.pm IO::Pipe extension Perl module |
626 | IO/Seekable.pm IO::Seekable extension Perl module |
627 | IO/Select.pm IO::Select extension Perl module |
628 | IO/Socket.pm IO::Socket extension Perl module |
629 | |
630 | Opcode.pm Disable named opcodes when compiling Perl code |
631 | |
632 | ExtUtils/Embed.pm Utilities for embedding Perl in C programs |
633 | ExtUtils/testlib.pm Fixes up @INC to use just-built extension |
634 | |
5f05dabc |
635 | FindBin.pm Find path of currently executing program |
636 | |
637 | Class/Template.pm Structure/member template builder |
638 | File/stat.pm Object-oriented wrapper around CORE::stat |
639 | Net/hostent.pm Object-oriented wrapper around CORE::gethost* |
640 | Net/netent.pm Object-oriented wrapper around CORE::getnet* |
641 | Net/protoent.pm Object-oriented wrapper around CORE::getproto* |
642 | Net/servent.pm Object-oriented wrapper around CORE::getserv* |
643 | Time/gmtime.pm Object-oriented wrapper around CORE::gmtime |
644 | Time/localtime.pm Object-oriented wrapper around CORE::localtime |
645 | Time/tm.pm Perl implementation of "struct tm" for {gm,local}time |
646 | User/grent.pm Object-oriented wrapper around CORE::getgr* |
647 | User/pwent.pm Object-oriented wrapper around CORE::getpw* |
648 | |
774d564b |
649 | Tie/RefHash.pm Base class for tied hashes with references as keys |
7a4c00b4 |
650 | |
5f05dabc |
651 | UNIVERSAL.pm Base class for *ALL* classes |
652 | |
54310121 |
653 | =head2 Fcntl |
654 | |
655 | New constants in the existing Fcntl modules are now supported, |
656 | provided that your operating system happens to support them: |
657 | |
658 | F_GETOWN F_SETOWN |
659 | O_ASYNC O_DEFER O_DSYNC O_FSYNC O_SYNC |
660 | O_EXLOCK O_SHLOCK |
661 | |
662 | These constants are intended for use with the Perl operators sysopen() |
663 | and fcntl() and the basic database modules like SDBM_File. For the |
664 | exact meaning of these and other Fcntl constants please refer to your |
665 | operating system's documentation for fcntl() and open(). |
666 | |
667 | In addition, the Fcntl module now provides these constants for use |
668 | with the Perl operator flock(): |
669 | |
670 | LOCK_SH LOCK_EX LOCK_NB LOCK_UN |
671 | |
672 | These constants are defined in all environments (because where there is |
673 | no flock() system call, Perl emulates it). However, for historical |
674 | reasons, these constants are not exported unless they are explicitly |
675 | requested with the ":flock" tag (e.g. C<use Fcntl ':flock'>). |
676 | |
5f05dabc |
677 | =head2 IO |
678 | |
679 | The IO module provides a simple mechanism to load all of the IO modules at one |
680 | go. Currently this includes: |
681 | |
682 | IO::Handle |
683 | IO::Seekable |
684 | IO::File |
685 | IO::Pipe |
686 | IO::Socket |
687 | |
688 | For more information on any of these modules, please see its |
689 | respective documentation. |
690 | |
691 | =head2 Math::Complex |
692 | |
693 | The Math::Complex module has been totally rewritten, and now supports |
694 | more operations. These are overloaded: |
695 | |
696 | + - * / ** <=> neg ~ abs sqrt exp log sin cos atan2 "" (stringify) |
697 | |
698 | And these functions are now exported: |
699 | |
700 | pi i Re Im arg |
701 | log10 logn cbrt root |
702 | tan cotan asin acos atan acotan |
703 | sinh cosh tanh cotanh asinh acosh atanh acotanh |
704 | cplx cplxe |
705 | |
5aabfad6 |
706 | =head2 Math::Trig |
707 | |
708 | This module provides a simpler interface to parts of Math::Complex for |
709 | those who need trigonometric functions only for real numbers. |
710 | |
0a753a76 |
711 | =head2 DB_File |
712 | |
713 | There have been quite a few changes made to DB_File. Here are a few of |
714 | the highlights: |
715 | |
716 | =over |
717 | |
718 | =item * |
719 | |
720 | Fixed a handful of bugs. |
721 | |
722 | =item * |
723 | |
724 | By public demand, added support for the standard hash function exists(). |
725 | |
726 | =item * |
727 | |
728 | Made it compatible with Berkeley DB 1.86. |
729 | |
730 | =item * |
731 | |
732 | Made negative subscripts work with RECNO interface. |
733 | |
734 | =item * |
735 | |
736 | Changed the default flags from O_RDWR to O_CREAT|O_RDWR and the default |
737 | mode from 0640 to 0666. |
738 | |
739 | =item * |
740 | |
741 | Made DB_File automatically import the open() constants (O_RDWR, |
742 | O_CREAT etc.) from Fcntl, if available. |
743 | |
744 | =item * |
745 | |
746 | Updated documentation. |
747 | |
748 | =back |
749 | |
750 | Refer to the HISTORY section in DB_File.pm for a complete list of |
751 | changes. Everything after DB_File 1.01 has been added since 5.003. |
752 | |
753 | =head2 Net::Ping |
754 | |
755 | Major rewrite - support added for both udp echo and real icmp pings. |
756 | |
54310121 |
757 | =head2 Object-oriented overrides for builtin operators |
5f05dabc |
758 | |
54310121 |
759 | Many of the Perl builtins returning lists now have |
5f05dabc |
760 | object-oriented overrides. These are: |
761 | |
762 | File::stat |
763 | Net::hostent |
764 | Net::netent |
765 | Net::protoent |
766 | Net::servent |
767 | Time::gmtime |
768 | Time::localtime |
769 | User::grent |
770 | User::pwent |
771 | |
772 | For example, you can now say |
773 | |
774 | use File::stat; |
775 | use User::pwent; |
776 | $his = (stat($filename)->st_uid == pwent($whoever)->pw_uid); |
777 | |
774d564b |
778 | =head1 Utility Changes |
5f05dabc |
779 | |
774d564b |
780 | =head2 xsubpp |
5f05dabc |
781 | |
0a753a76 |
782 | =over |
783 | |
774d564b |
784 | =item C<void> XSUBs now default to returning nothing |
785 | |
786 | Due to a documentation/implementation bug in previous versions of |
787 | Perl, XSUBs with a return type of C<void> have actually been |
788 | returning one value. Usually that value was the GV for the XSUB, |
789 | but sometimes it was some already freed or reused value, which would |
790 | sometimes lead to program failure. |
791 | |
792 | In Perl 5.004, if an XSUB is declared as returning C<void>, it |
793 | actually returns no value, i.e. an empty list (though there is a |
794 | backward-compatibility exception; see below). If your XSUB really |
795 | does return an SV, you should give it a return type of C<SV *>. |
796 | |
797 | For backward compatibility, I<xsubpp> tries to guess whether a |
798 | C<void> XSUB is really C<void> or if it wants to return an C<SV *>. |
799 | It does so by examining the text of the XSUB: if I<xsubpp> finds |
800 | what looks like an assignment to C<ST(0)>, it assumes that the |
801 | XSUB's return type is really C<SV *>. |
5f05dabc |
802 | |
0a753a76 |
803 | =back |
804 | |
805 | =head1 C Language API Changes |
806 | |
807 | =over |
808 | |
809 | =item C<gv_fetchmethod> and C<perl_call_sv> |
810 | |
811 | The C<gv_fetchmethod> function finds a method for an object, just like |
812 | in Perl 5.003. The GV it returns may be a method cache entry. |
813 | However, in Perl 5.004, method cache entries are not visible to users; |
814 | therefore, they can no longer be passed directly to C<perl_call_sv>. |
815 | Instead, you should use the C<GvCV> macro on the GV to extract its CV, |
816 | and pass the CV to C<perl_call_sv>. |
817 | |
818 | The most likely symptom of passing the result of C<gv_fetchmethod> to |
819 | C<perl_call_sv> is Perl's producing an "Undefined subroutine called" |
820 | error on the I<second> call to a given method (since there is no cache |
821 | on the first call). |
822 | |
1e422769 |
823 | =item Extended API for manipulating hashes |
824 | |
825 | Internal handling of hash keys has changed. The old hashtable API is |
826 | still fully supported, and will likely remain so. The additions to the |
827 | API allow passing keys as C<SV*>s, so that C<tied> hashes can be given |
54310121 |
828 | real scalars as keys rather than plain strings (nontied hashes still |
1e422769 |
829 | can only use strings as keys). New extensions must use the new hash |
830 | access functions and macros if they wish to use C<SV*> keys. These |
831 | additions also make it feasible to manipulate C<HE*>s (hash entries), |
832 | which can be more efficient. See L<perlguts> for details. |
833 | |
0a753a76 |
834 | =back |
835 | |
5f05dabc |
836 | =head1 Documentation Changes |
837 | |
838 | Many of the base and library pods were updated. These |
839 | new pods are included in section 1: |
840 | |
0a753a76 |
841 | =over |
5f05dabc |
842 | |
774d564b |
843 | =item L<perldelta> |
5f05dabc |
844 | |
71be2cbc |
845 | This document. |
5f05dabc |
846 | |
71be2cbc |
847 | =item L<perllocale> |
5f05dabc |
848 | |
71be2cbc |
849 | Locale support (internationalization and localization). |
5f05dabc |
850 | |
851 | =item L<perltoot> |
852 | |
853 | Tutorial on Perl OO programming. |
854 | |
71be2cbc |
855 | =item L<perlapio> |
856 | |
857 | Perl internal IO abstraction interface. |
858 | |
5f05dabc |
859 | =item L<perldebug> |
860 | |
861 | Although not new, this has been massively updated. |
862 | |
863 | =item L<perlsec> |
864 | |
865 | Although not new, this has been massively updated. |
866 | |
867 | =back |
868 | |
869 | =head1 New Diagnostics |
870 | |
871 | Several new conditions will trigger warnings that were |
872 | silent before. Some only affect certain platforms. |
2ae324a7 |
873 | The following new warnings and errors outline these. |
774d564b |
874 | These messages are classified as follows (listed in |
875 | increasing order of desperation): |
876 | |
877 | (W) A warning (optional). |
878 | (D) A deprecation (optional). |
879 | (S) A severe warning (mandatory). |
880 | (F) A fatal error (trappable). |
881 | (P) An internal error you should never see (trappable). |
54310121 |
882 | (X) A very fatal error (nontrappable). |
774d564b |
883 | (A) An alien error message (not generated by Perl). |
5f05dabc |
884 | |
0a753a76 |
885 | =over |
5f05dabc |
886 | |
887 | =item "my" variable %s masks earlier declaration in same scope |
888 | |
889 | (S) A lexical variable has been redeclared in the same scope, effectively |
890 | eliminating all access to the previous instance. This is almost always |
891 | a typographical error. Note that the earlier variable will still exist |
892 | until the end of the scope or until all closure referents to it are |
893 | destroyed. |
894 | |
774d564b |
895 | =item %s argument is not a HASH element or slice |
896 | |
897 | (F) The argument to delete() must be either a hash element, such as |
898 | |
899 | $foo{$bar} |
900 | $ref->[12]->{"susie"} |
901 | |
902 | or a hash slice, such as |
903 | |
904 | @foo{$bar, $baz, $xyzzy} |
905 | @{$ref->[12]}{"susie", "queue"} |
906 | |
5f05dabc |
907 | =item Allocation too large: %lx |
908 | |
54310121 |
909 | (X) You can't allocate more than 64K on an MS-DOS machine. |
5f05dabc |
910 | |
911 | =item Allocation too large |
912 | |
913 | (F) You can't allocate more than 2^31+"small amount" bytes. |
914 | |
54310121 |
915 | =item Applying %s to %s will act on scalar(%s) |
916 | |
917 | (W) The pattern match (//), substitution (s///), and translation (tr///) |
918 | operators work on scalar values. If you apply one of them to an array |
919 | or a hash, it will convert the array or hash to a scalar value -- the |
920 | length of an array, or the population info of a hash -- and then work on |
921 | that scalar value. This is probably not what you meant to do. See |
922 | L<perlfunc/grep> and L<perlfunc/map> for alternatives. |
923 | |
924 | =item Attempt to free nonexistent shared string |
5f05dabc |
925 | |
926 | (P) Perl maintains a reference counted internal table of strings to |
927 | optimize the storage and access of hash keys and other strings. This |
928 | indicates someone tried to decrement the reference count of a string |
929 | that can no longer be found in the table. |
930 | |
931 | =item Attempt to use reference as lvalue in substr |
932 | |
933 | (W) You supplied a reference as the first argument to substr() used |
934 | as an lvalue, which is pretty strange. Perhaps you forgot to |
935 | dereference it first. See L<perlfunc/substr>. |
936 | |
774d564b |
937 | =item Can't use bareword ("%s") as %s ref while "strict refs" in use |
938 | |
939 | (F) Only hard references are allowed by "strict refs". Symbolic references |
940 | are disallowed. See L<perlref>. |
941 | |
54310121 |
942 | =item Cannot resolve method `%s' overloading `%s' in package `%s' |
943 | |
944 | (P) Internal error trying to resolve overloading specified by a method |
945 | name (as opposed to a subroutine reference). |
946 | |
774d564b |
947 | =item Constant subroutine %s redefined |
948 | |
949 | (S) You redefined a subroutine which had previously been eligible for |
dc848c6f |
950 | inlining. See L<perlsub/"Constant Functions"> for commentary and |
54310121 |
951 | workarounds. |
952 | |
953 | =item Constant subroutine %s undefined |
954 | |
955 | (S) You undefined a subroutine which had previously been eligible for |
774d564b |
956 | inlining. See L<perlsub/"Constant Functions"> for commentary and |
957 | workarounds. |
958 | |
54310121 |
959 | =item Copy method did not return a reference |
960 | |
961 | (F) The method which overloads "=" is buggy. See L<overload/Copy Constructor>. |
962 | |
774d564b |
963 | =item Died |
964 | |
965 | (F) You passed die() an empty string (the equivalent of C<die "">) or |
966 | you called it with no args and both C<$@> and C<$_> were empty. |
967 | |
54310121 |
968 | =item Exiting pseudo-block via %s |
969 | |
970 | (W) You are exiting a rather special block construct (like a sort block or |
971 | subroutine) by unconventional means, such as a goto, or a loop control |
972 | statement. See L<perlfunc/sort>. |
973 | |
974 | =item Illegal character %s (carriage return) |
975 | |
976 | (F) A carriage return character was found in the input. This is an |
977 | error, and not a warning, because carriage return characters can break |
978 | multi-line strings, including here documents (e.g., C<print E<lt>E<lt>EOF;>). |
979 | |
980 | =item Illegal switch in PERL5OPT: %s |
981 | |
982 | (X) The PERL5OPT environment variable may only be used to set the |
983 | following switches: B<-[DIMUdmw]>. |
984 | |
5f05dabc |
985 | =item Integer overflow in hex number |
986 | |
987 | (S) The literal hex number you have specified is too big for your |
988 | architecture. On a 32-bit architecture the largest hex literal is |
989 | 0xFFFFFFFF. |
990 | |
991 | =item Integer overflow in octal number |
992 | |
993 | (S) The literal octal number you have specified is too big for your |
994 | architecture. On a 32-bit architecture the largest octal literal is |
995 | 037777777777. |
996 | |
774d564b |
997 | =item Name "%s::%s" used only once: possible typo |
998 | |
999 | (W) Typographical errors often show up as unique variable names. |
1000 | If you had a good reason for having a unique name, then just mention |
1001 | it again somehow to suppress the message (the C<use vars> pragma is |
1002 | provided for just this purpose). |
1003 | |
5f05dabc |
1004 | =item Null picture in formline |
1005 | |
1006 | (F) The first argument to formline must be a valid format picture |
1007 | specification. It was found to be empty, which probably means you |
1008 | supplied it an uninitialized value. See L<perlform>. |
1009 | |
1010 | =item Offset outside string |
1011 | |
1012 | (F) You tried to do a read/write/send/recv operation with an offset |
1013 | pointing outside the buffer. This is difficult to imagine. |
1014 | The sole exception to this is that C<sysread()>ing past the buffer |
1015 | will extend the buffer and zero pad the new area. |
1016 | |
1017 | =item Out of memory! |
1018 | |
1019 | (X|F) The malloc() function returned 0, indicating there was insufficient |
1020 | remaining memory (or virtual memory) to satisfy the request. |
1021 | |
1022 | The request was judged to be small, so the possibility to trap it |
1023 | depends on the way Perl was compiled. By default it is not trappable. |
1024 | However, if compiled for this, Perl may use the contents of C<$^M> as |
1025 | an emergency pool after die()ing with this message. In this case the |
1026 | error is trappable I<once>. |
1027 | |
1028 | =item Out of memory during request for %s |
1029 | |
1030 | (F) The malloc() function returned 0, indicating there was insufficient |
1031 | remaining memory (or virtual memory) to satisfy the request. However, |
1032 | the request was judged large enough (compile-time default is 64K), so |
1033 | a possibility to shut down by trapping this error is granted. |
1034 | |
1035 | =item Possible attempt to put comments in qw() list |
1036 | |
774d564b |
1037 | (W) qw() lists contain items separated by whitespace; as with literal |
1038 | strings, comment characters are not ignored, but are instead treated |
1039 | as literal data. (You may have used different delimiters than the |
1040 | exclamation marks parentheses shown here; braces are also frequently |
1041 | used.) |
1042 | |
1043 | You probably wrote something like this: |
5f05dabc |
1044 | |
2ae324a7 |
1045 | @list = qw( |
774d564b |
1046 | a # a comment |
5f05dabc |
1047 | b # another comment |
774d564b |
1048 | ); |
5f05dabc |
1049 | |
1050 | when you should have written this: |
1051 | |
774d564b |
1052 | @list = qw( |
2ae324a7 |
1053 | a |
5f05dabc |
1054 | b |
774d564b |
1055 | ); |
1056 | |
1057 | If you really want comments, build your list the |
1058 | old-fashioned way, with quotes and commas: |
1059 | |
1060 | @list = ( |
1061 | 'a', # a comment |
1062 | 'b', # another comment |
1063 | ); |
5f05dabc |
1064 | |
1065 | =item Possible attempt to separate words with commas |
1066 | |
774d564b |
1067 | (W) qw() lists contain items separated by whitespace; therefore commas |
1068 | aren't needed to separate the items. (You may have used different |
1069 | delimiters than the parentheses shown here; braces are also frequently |
1070 | used.) |
5f05dabc |
1071 | |
2ae324a7 |
1072 | You probably wrote something like this: |
5f05dabc |
1073 | |
774d564b |
1074 | qw! a, b, c !; |
1075 | |
1076 | which puts literal commas into some of the list items. Write it without |
1077 | commas if you don't want them to appear in your data: |
1078 | |
1079 | qw! a b c !; |
5f05dabc |
1080 | |
774d564b |
1081 | =item Scalar value @%s{%s} better written as $%s{%s} |
1082 | |
1083 | (W) You've used a hash slice (indicated by @) to select a single element of |
1084 | a hash. Generally it's better to ask for a scalar value (indicated by $). |
1085 | The difference is that C<$foo{&bar}> always behaves like a scalar, both when |
1086 | assigning to it and when evaluating its argument, while C<@foo{&bar}> behaves |
1087 | like a list when you assign to it, and provides a list context to its |
1088 | subscript, which can do weird things if you're expecting only one subscript. |
5f05dabc |
1089 | |
54310121 |
1090 | =item Stub found while resolving method `%s' overloading `%s' in package `%s' |
1091 | |
1092 | (P) Overloading resolution over @ISA tree may be broken by importing stubs. |
1093 | Stubs should never be implicitely created, but explicit calls to C<can> |
1094 | may break this. |
1095 | |
1096 | =item Too late for "B<-T>" option |
1097 | |
1098 | (X) The #! line (or local equivalent) in a Perl script contains the |
1099 | B<-T> option, but Perl was not invoked with B<-T> in its argument |
1100 | list. This is an error because, by the time Perl discovers a B<-T> in |
1101 | a script, it's too late to properly taint everything from the |
1102 | environment. So Perl gives up. |
1103 | |
5f05dabc |
1104 | =item untie attempted while %d inner references still exist |
1105 | |
1106 | (W) A copy of the object returned from C<tie> (or C<tied>) was still |
1107 | valid when C<untie> was called. |
1108 | |
54310121 |
1109 | =item Unrecognized character %s |
1110 | |
1111 | (F) The Perl parser has no idea what to do with the specified character |
1112 | in your Perl script (or eval). Perhaps you tried to run a compressed |
1113 | script, a binary program, or a directory as a Perl program. |
1114 | |
1115 | =item Unsupported function fork |
1116 | |
1117 | (F) Your version of executable does not support forking. |
1118 | |
1119 | Note that under some systems, like OS/2, there may be different flavors of |
1120 | Perl executables, some of which may support fork, some not. Try changing |
1121 | the name you call Perl by to C<perl_>, C<perl__>, and so on. |
1122 | |
1123 | =item Value of %s can be "0"; test with defined() |
774d564b |
1124 | |
54310121 |
1125 | (W) In a conditional expression, you used <HANDLE>, <*> (glob), C<each()>, |
1126 | or C<readdir()> as a boolean value. Each of these constructs can return a |
1127 | value of "0"; that would make the conditional expression false, which is |
1128 | probably not what you intended. When using these constructs in conditional |
1129 | expressions, test their values with the C<defined> operator. |
774d564b |
1130 | |
1131 | =item Variable "%s" may be unavailable |
1132 | |
1133 | (W) An inner (nested) I<anonymous> subroutine is inside a I<named> |
1134 | subroutine, and outside that is another subroutine; and the anonymous |
1135 | (innermost) subroutine is referencing a lexical variable defined in |
1136 | the outermost subroutine. For example: |
1137 | |
1138 | sub outermost { my $a; sub middle { sub { $a } } } |
1139 | |
1140 | If the anonymous subroutine is called or referenced (directly or |
1141 | indirectly) from the outermost subroutine, it will share the variable |
1142 | as you would expect. But if the anonymous subroutine is called or |
1143 | referenced when the outermost subroutine is not active, it will see |
1144 | the value of the shared variable as it was before and during the |
1145 | *first* call to the outermost subroutine, which is probably not what |
1146 | you want. |
1147 | |
1148 | In these circumstances, it is usually best to make the middle |
1149 | subroutine anonymous, using the C<sub {}> syntax. Perl has specific |
1150 | support for shared variables in nested anonymous subroutines; a named |
1151 | subroutine in between interferes with this feature. |
1152 | |
1153 | =item Variable "%s" will not stay shared |
1154 | |
1155 | (W) An inner (nested) I<named> subroutine is referencing a lexical |
1156 | variable defined in an outer subroutine. |
1157 | |
1158 | When the inner subroutine is called, it will probably see the value of |
1159 | the outer subroutine's variable as it was before and during the |
1160 | *first* call to the outer subroutine; in this case, after the first |
1161 | call to the outer subroutine is complete, the inner and outer |
1162 | subroutines will no longer share a common value for the variable. In |
1163 | other words, the variable will no longer be shared. |
1164 | |
1165 | Furthermore, if the outer subroutine is anonymous and references a |
1166 | lexical variable outside itself, then the outer and inner subroutines |
1167 | will I<never> share the given variable. |
1168 | |
1169 | This problem can usually be solved by making the inner subroutine |
1170 | anonymous, using the C<sub {}> syntax. When inner anonymous subs that |
1171 | reference variables in outer subroutines are called or referenced, |
54310121 |
1172 | they are automatically rebound to the current values of such |
774d564b |
1173 | variables. |
1174 | |
1175 | =item Warning: something's wrong |
1176 | |
1177 | (W) You passed warn() an empty string (the equivalent of C<warn "">) or |
1178 | you called it with no args and C<$_> was empty. |
1179 | |
54310121 |
1180 | =item Ill-formed logical name |%s| in prime_env_iter |
1181 | |
1182 | (W) A warning peculiar to VMS. A logical name was encountered when preparing |
1183 | to iterate over %ENV which violates the syntactic rules governing logical |
1184 | names. Since it cannot be translated normally, it is skipped, and will not |
1185 | appear in %ENV. This may be a benign occurrence, as some software packages |
1186 | might directly modify logical name tables and introduce nonstandard names, |
1187 | or it may indicate that a logical name table has been corrupted. |
1188 | |
774d564b |
1189 | =item Got an error from DosAllocMem |
5f05dabc |
1190 | |
774d564b |
1191 | (P) An error peculiar to OS/2. Most probably you're using an obsolete |
1192 | version of Perl, and this should not happen anyway. |
5f05dabc |
1193 | |
1194 | =item Malformed PERLLIB_PREFIX |
1195 | |
dc848c6f |
1196 | (F) An error peculiar to OS/2. PERLLIB_PREFIX should be of the form |
5f05dabc |
1197 | |
1198 | prefix1;prefix2 |
1199 | |
1200 | or |
1201 | |
1202 | prefix1 prefix2 |
1203 | |
dc848c6f |
1204 | with nonempty prefix1 and prefix2. If C<prefix1> is indeed a prefix |
1205 | of a builtin library search path, prefix2 is substituted. The error |
1206 | may appear if components are not found, or are too long. See |
1207 | "PERLLIB_PREFIX" in F<README.os2>. |
5f05dabc |
1208 | |
1209 | =item PERL_SH_DIR too long |
1210 | |
1211 | (F) An error peculiar to OS/2. PERL_SH_DIR is the directory to find the |
dc848c6f |
1212 | C<sh>-shell in. See "PERL_SH_DIR" in F<README.os2>. |
5f05dabc |
1213 | |
1214 | =item Process terminated by SIG%s |
1215 | |
1216 | (W) This is a standard message issued by OS/2 applications, while *nix |
dc848c6f |
1217 | applications die in silence. It is considered a feature of the OS/2 |
1218 | port. One can easily disable this by appropriate sighandlers, see |
1219 | L<perlipc/"Signals">. See also "Process terminated by SIGTERM/SIGINT" |
1220 | in F<README.os2>. |
5f05dabc |
1221 | |
1222 | =back |
1223 | |
1224 | =head1 BUGS |
1225 | |
774d564b |
1226 | If you find what you think is a bug, you might check the headers of |
1227 | recently posted articles in the comp.lang.perl.misc newsgroup. |
1228 | There may also be information at http://www.perl.com/perl/, the Perl |
1229 | Home Page. |
5f05dabc |
1230 | |
1231 | If you believe you have an unreported bug, please run the B<perlbug> |
9607fc9c |
1232 | program included with your release. Make sure you trim your bug down |
1233 | to a tiny but sufficient test case. Your bug report, along with the |
1234 | output of C<perl -V>, will be sent off to <F<perlbug@perl.com>> to be |
1235 | analysed by the Perl porting team. |
5f05dabc |
1236 | |
1237 | =head1 SEE ALSO |
1238 | |
1239 | The F<Changes> file for exhaustive details on what changed. |
1240 | |
1241 | The F<INSTALL> file for how to build Perl. This file has been |
1242 | significantly updated for 5.004, so even veteran users should |
1243 | look through it. |
1244 | |
1245 | The F<README> file for general stuff. |
1246 | |
1247 | The F<Copying> file for copyright information. |
1248 | |
1249 | =head1 HISTORY |
1250 | |
1251 | Constructed by Tom Christiansen, grabbing material with permission |
1252 | from innumerable contributors, with kibitzing by more than a few Perl |
1253 | porters. |
1254 | |
2ae324a7 |
1255 | Last update: Sat Mar 8 19:51:26 EST 1997 |