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954c1994 GS |
1 | =head1 NAME |
2 | ||
1c846c1f | 3 | perlintern - autogenerated documentation of purely B<internal> |
954c1994 GS |
4 | Perl functions |
5 | ||
6 | =head1 DESCRIPTION | |
d8c40edc | 7 | X<internal Perl functions> X<interpreter functions> |
954c1994 | 8 | |
1c846c1f | 9 | This file is the autogenerated documentation of functions in the |
4375e838 | 10 | Perl interpreter that are documented using Perl's internal documentation |
1c846c1f | 11 | format but are not marked as part of the Perl API. In other words, |
954c1994 GS |
12 | B<they are not for use in extensions>! |
13 | ||
a8586c98 | 14 | |
7dafbf52 DM |
15 | =head1 CV reference counts and CvOUTSIDE |
16 | ||
17 | =over 8 | |
18 | ||
19 | =item CvWEAKOUTSIDE | |
d8c40edc | 20 | X<CvWEAKOUTSIDE> |
7dafbf52 DM |
21 | |
22 | Each CV has a pointer, C<CvOUTSIDE()>, to its lexically enclosing | |
23 | CV (if any). Because pointers to anonymous sub prototypes are | |
24 | stored in C<&> pad slots, it is a possible to get a circular reference, | |
25 | with the parent pointing to the child and vice-versa. To avoid the | |
26 | ensuing memory leak, we do not increment the reference count of the CV | |
27 | pointed to by C<CvOUTSIDE> in the I<one specific instance> that the parent | |
28 | has a C<&> pad slot pointing back to us. In this case, we set the | |
29 | C<CvWEAKOUTSIDE> flag in the child. This allows us to determine under what | |
30 | circumstances we should decrement the refcount of the parent when freeing | |
31 | the child. | |
32 | ||
28a5cf3b | 33 | There is a further complication with non-closure anonymous subs (i.e. those |
7dafbf52 DM |
34 | that do not refer to any lexicals outside that sub). In this case, the |
35 | anonymous prototype is shared rather than being cloned. This has the | |
36 | consequence that the parent may be freed while there are still active | |
37 | children, eg | |
38 | ||
39 | BEGIN { $a = sub { eval '$x' } } | |
40 | ||
41 | In this case, the BEGIN is freed immediately after execution since there | |
42 | are no active references to it: the anon sub prototype has | |
43 | C<CvWEAKOUTSIDE> set since it's not a closure, and $a points to the same | |
44 | CV, so it doesn't contribute to BEGIN's refcount either. When $a is | |
45 | executed, the C<eval '$x'> causes the chain of C<CvOUTSIDE>s to be followed, | |
46 | and the freed BEGIN is accessed. | |
47 | ||
48 | To avoid this, whenever a CV and its associated pad is freed, any | |
49 | C<&> entries in the pad are explicitly removed from the pad, and if the | |
50 | refcount of the pointed-to anon sub is still positive, then that | |
51 | child's C<CvOUTSIDE> is set to point to its grandparent. This will only | |
52 | occur in the single specific case of a non-closure anon prototype | |
53 | having one or more active references (such as C<$a> above). | |
54 | ||
55 | One other thing to consider is that a CV may be merely undefined | |
56 | rather than freed, eg C<undef &foo>. In this case, its refcount may | |
57 | not have reached zero, but we still delete its pad and its C<CvROOT> etc. | |
58 | Since various children may still have their C<CvOUTSIDE> pointing at this | |
59 | undefined CV, we keep its own C<CvOUTSIDE> for the time being, so that | |
60 | the chain of lexical scopes is unbroken. For example, the following | |
61 | should print 123: | |
62 | ||
63 | my $x = 123; | |
64 | sub tmp { sub { eval '$x' } } | |
65 | my $a = tmp(); | |
66 | undef &tmp; | |
67 | print $a->(); | |
68 | ||
69 | bool CvWEAKOUTSIDE(CV *cv) | |
70 | ||
71 | =for hackers | |
72 | Found in file cv.h | |
73 | ||
74 | ||
75 | =back | |
76 | ||
dd2155a4 DM |
77 | =head1 Functions in file pad.h |
78 | ||
79 | ||
80 | =over 8 | |
81 | ||
82 | =item CX_CURPAD_SAVE | |
d8c40edc | 83 | X<CX_CURPAD_SAVE> |
dd2155a4 DM |
84 | |
85 | Save the current pad in the given context block structure. | |
86 | ||
87 | void CX_CURPAD_SAVE(struct context) | |
88 | ||
89 | =for hackers | |
90 | Found in file pad.h | |
91 | ||
92 | =item CX_CURPAD_SV | |
d8c40edc | 93 | X<CX_CURPAD_SV> |
dd2155a4 DM |
94 | |
95 | Access the SV at offset po in the saved current pad in the given | |
96 | context block structure (can be used as an lvalue). | |
97 | ||
f3548bdc | 98 | SV * CX_CURPAD_SV(struct context, PADOFFSET po) |
dd2155a4 DM |
99 | |
100 | =for hackers | |
101 | Found in file pad.h | |
102 | ||
d8c40edc AT |
103 | =item PAD_BASE_SV |
104 | X<PAD_BASE_SV> | |
dd2155a4 DM |
105 | |
106 | Get the value from slot C<po> in the base (DEPTH=1) pad of a padlist | |
107 | ||
d8c40edc | 108 | SV * PAD_BASE_SV(PADLIST padlist, PADOFFSET po) |
dd2155a4 DM |
109 | |
110 | =for hackers | |
111 | Found in file pad.h | |
112 | ||
113 | =item PAD_CLONE_VARS | |
d8c40edc | 114 | X<PAD_CLONE_VARS> |
dd2155a4 DM |
115 | |
116 | |CLONE_PARAMS* param | |
117 | Clone the state variables associated with running and compiling pads. | |
118 | ||
119 | void PAD_CLONE_VARS(PerlInterpreter *proto_perl \) | |
120 | ||
121 | =for hackers | |
122 | Found in file pad.h | |
123 | ||
124 | =item PAD_COMPNAME_FLAGS | |
d8c40edc | 125 | X<PAD_COMPNAME_FLAGS> |
dd2155a4 DM |
126 | |
127 | Return the flags for the current compiling pad name | |
128 | at offset C<po>. Assumes a valid slot entry. | |
129 | ||
130 | U32 PAD_COMPNAME_FLAGS(PADOFFSET po) | |
131 | ||
132 | =for hackers | |
133 | Found in file pad.h | |
134 | ||
135 | =item PAD_COMPNAME_GEN | |
d8c40edc | 136 | X<PAD_COMPNAME_GEN> |
dd2155a4 DM |
137 | |
138 | The generation number of the name at offset C<po> in the current | |
139 | compiling pad (lvalue). Note that C<SvCUR> is hijacked for this purpose. | |
140 | ||
141 | STRLEN PAD_COMPNAME_GEN(PADOFFSET po) | |
142 | ||
143 | =for hackers | |
144 | Found in file pad.h | |
145 | ||
27da23d5 | 146 | =item PAD_COMPNAME_GEN_set |
d8c40edc | 147 | X<PAD_COMPNAME_GEN_set> |
27da23d5 JH |
148 | |
149 | Sets the generation number of the name at offset C<po> in the current | |
150 | ling pad (lvalue) to C<gen>. Note that C<SvCUR_set> is hijacked for this purpose. | |
151 | ||
152 | STRLEN PAD_COMPNAME_GEN_set(PADOFFSET po, int gen) | |
153 | ||
154 | =for hackers | |
155 | Found in file pad.h | |
156 | ||
dd2155a4 | 157 | =item PAD_COMPNAME_OURSTASH |
d8c40edc | 158 | X<PAD_COMPNAME_OURSTASH> |
dd2155a4 DM |
159 | |
160 | Return the stash associated with an C<our> variable. | |
161 | Assumes the slot entry is a valid C<our> lexical. | |
162 | ||
163 | HV * PAD_COMPNAME_OURSTASH(PADOFFSET po) | |
164 | ||
165 | =for hackers | |
166 | Found in file pad.h | |
167 | ||
168 | =item PAD_COMPNAME_PV | |
d8c40edc | 169 | X<PAD_COMPNAME_PV> |
dd2155a4 DM |
170 | |
171 | Return the name of the current compiling pad name | |
172 | at offset C<po>. Assumes a valid slot entry. | |
173 | ||
174 | char * PAD_COMPNAME_PV(PADOFFSET po) | |
175 | ||
176 | =for hackers | |
177 | Found in file pad.h | |
178 | ||
179 | =item PAD_COMPNAME_TYPE | |
d8c40edc | 180 | X<PAD_COMPNAME_TYPE> |
dd2155a4 DM |
181 | |
182 | Return the type (stash) of the current compiling pad name at offset | |
183 | C<po>. Must be a valid name. Returns null if not typed. | |
184 | ||
185 | HV * PAD_COMPNAME_TYPE(PADOFFSET po) | |
186 | ||
187 | =for hackers | |
188 | Found in file pad.h | |
189 | ||
190 | =item PAD_DUP | |
d8c40edc | 191 | X<PAD_DUP> |
dd2155a4 DM |
192 | |
193 | Clone a padlist. | |
194 | ||
195 | void PAD_DUP(PADLIST dstpad, PADLIST srcpad, CLONE_PARAMS* param) | |
196 | ||
197 | =for hackers | |
198 | Found in file pad.h | |
199 | ||
f3548bdc | 200 | =item PAD_RESTORE_LOCAL |
d8c40edc | 201 | X<PAD_RESTORE_LOCAL> |
f3548bdc DM |
202 | |
203 | Restore the old pad saved into the local variable opad by PAD_SAVE_LOCAL() | |
204 | ||
205 | void PAD_RESTORE_LOCAL(PAD *opad) | |
206 | ||
207 | =for hackers | |
208 | Found in file pad.h | |
209 | ||
210 | =item PAD_SAVE_LOCAL | |
d8c40edc | 211 | X<PAD_SAVE_LOCAL> |
f3548bdc DM |
212 | |
213 | Save the current pad to the local variable opad, then make the | |
214 | current pad equal to npad | |
215 | ||
216 | void PAD_SAVE_LOCAL(PAD *opad, PAD *npad) | |
217 | ||
218 | =for hackers | |
219 | Found in file pad.h | |
220 | ||
dd2155a4 | 221 | =item PAD_SAVE_SETNULLPAD |
d8c40edc | 222 | X<PAD_SAVE_SETNULLPAD> |
dd2155a4 DM |
223 | |
224 | Save the current pad then set it to null. | |
225 | ||
226 | void PAD_SAVE_SETNULLPAD() | |
227 | ||
228 | =for hackers | |
229 | Found in file pad.h | |
230 | ||
d8c40edc AT |
231 | =item PAD_SETSV |
232 | X<PAD_SETSV> | |
dd2155a4 DM |
233 | |
234 | Set the slot at offset C<po> in the current pad to C<sv> | |
235 | ||
d8c40edc | 236 | SV * PAD_SETSV(PADOFFSET po, SV* sv) |
dd2155a4 DM |
237 | |
238 | =for hackers | |
239 | Found in file pad.h | |
240 | ||
d8c40edc AT |
241 | =item PAD_SET_CUR |
242 | X<PAD_SET_CUR> | |
dd2155a4 DM |
243 | |
244 | Set the current pad to be pad C<n> in the padlist, saving | |
f54ba1c2 DM |
245 | the previous current pad. NB currently this macro expands to a string too |
246 | long for some compilers, so it's best to replace it with | |
247 | ||
248 | SAVECOMPPAD(); | |
249 | PAD_SET_CUR_NOSAVE(padlist,n); | |
250 | ||
dd2155a4 | 251 | |
d8c40edc | 252 | void PAD_SET_CUR(PADLIST padlist, I32 n) |
dd2155a4 DM |
253 | |
254 | =for hackers | |
255 | Found in file pad.h | |
256 | ||
d8c40edc AT |
257 | =item PAD_SET_CUR_NOSAVE |
258 | X<PAD_SET_CUR_NOSAVE> | |
bf9cdc68 RG |
259 | |
260 | like PAD_SET_CUR, but without the save | |
261 | ||
d8c40edc | 262 | void PAD_SET_CUR_NOSAVE(PADLIST padlist, I32 n) |
bf9cdc68 RG |
263 | |
264 | =for hackers | |
265 | Found in file pad.h | |
266 | ||
d8c40edc AT |
267 | =item PAD_SV |
268 | X<PAD_SV> | |
dd2155a4 DM |
269 | |
270 | Get the value at offset C<po> in the current pad | |
271 | ||
d8c40edc | 272 | void PAD_SV(PADOFFSET po) |
dd2155a4 DM |
273 | |
274 | =for hackers | |
275 | Found in file pad.h | |
276 | ||
d8c40edc AT |
277 | =item PAD_SVl |
278 | X<PAD_SVl> | |
dd2155a4 DM |
279 | |
280 | Lightweight and lvalue version of C<PAD_SV>. | |
281 | Get or set the value at offset C<po> in the current pad. | |
282 | Unlike C<PAD_SV>, does not print diagnostics with -DX. | |
283 | For internal use only. | |
284 | ||
d8c40edc | 285 | SV * PAD_SVl(PADOFFSET po) |
dd2155a4 DM |
286 | |
287 | =for hackers | |
288 | Found in file pad.h | |
289 | ||
d8c40edc AT |
290 | =item SAVECLEARSV |
291 | X<SAVECLEARSV> | |
dd2155a4 | 292 | |
28a5cf3b | 293 | Clear the pointed to pad value on scope exit. (i.e. the runtime action of 'my') |
dd2155a4 | 294 | |
d8c40edc | 295 | void SAVECLEARSV(SV **svp) |
dd2155a4 DM |
296 | |
297 | =for hackers | |
298 | Found in file pad.h | |
299 | ||
300 | =item SAVECOMPPAD | |
d8c40edc | 301 | X<SAVECOMPPAD> |
dd2155a4 DM |
302 | |
303 | save PL_comppad and PL_curpad | |
304 | ||
dd2155a4 | 305 | |
dd2155a4 DM |
306 | |
307 | ||
308 | ||
f3548bdc | 309 | void SAVECOMPPAD() |
dd2155a4 DM |
310 | |
311 | =for hackers | |
312 | Found in file pad.h | |
313 | ||
d8c40edc AT |
314 | =item SAVEPADSV |
315 | X<SAVEPADSV> | |
dd2155a4 DM |
316 | |
317 | Save a pad slot (used to restore after an iteration) | |
318 | ||
f3548bdc | 319 | XXX DAPM it would make more sense to make the arg a PADOFFSET |
d8c40edc | 320 | void SAVEPADSV(PADOFFSET po) |
dd2155a4 DM |
321 | |
322 | =for hackers | |
323 | Found in file pad.h | |
324 | ||
325 | ||
326 | =back | |
327 | ||
a3985cdc DM |
328 | =head1 Functions in file pp_ctl.c |
329 | ||
330 | ||
331 | =over 8 | |
332 | ||
333 | =item find_runcv | |
d8c40edc | 334 | X<find_runcv> |
a3985cdc DM |
335 | |
336 | Locate the CV corresponding to the currently executing sub or eval. | |
d819b83a DM |
337 | If db_seqp is non_null, skip CVs that are in the DB package and populate |
338 | *db_seqp with the cop sequence number at the point that the DB:: code was | |
339 | entered. (allows debuggers to eval in the scope of the breakpoint rather | |
324092c6 | 340 | than in the scope of the debugger itself). |
a3985cdc | 341 | |
d819b83a | 342 | CV* find_runcv(U32 *db_seqp) |
a3985cdc DM |
343 | |
344 | =for hackers | |
345 | Found in file pp_ctl.c | |
346 | ||
347 | ||
348 | =back | |
349 | ||
a4f1a029 | 350 | =head1 Global Variables |
78f9721b | 351 | |
a4f1a029 | 352 | =over 8 |
78f9721b | 353 | |
2eb25c99 | 354 | =item PL_DBsingle |
d8c40edc | 355 | X<PL_DBsingle> |
2eb25c99 JH |
356 | |
357 | When Perl is run in debugging mode, with the B<-d> switch, this SV is a | |
358 | boolean which indicates whether subs are being single-stepped. | |
359 | Single-stepping is automatically turned on after every step. This is the C | |
360 | variable which corresponds to Perl's $DB::single variable. See | |
361 | C<PL_DBsub>. | |
362 | ||
363 | SV * PL_DBsingle | |
364 | ||
365 | =for hackers | |
366 | Found in file intrpvar.h | |
367 | ||
368 | =item PL_DBsub | |
d8c40edc | 369 | X<PL_DBsub> |
2eb25c99 JH |
370 | |
371 | When Perl is run in debugging mode, with the B<-d> switch, this GV contains | |
372 | the SV which holds the name of the sub being debugged. This is the C | |
373 | variable which corresponds to Perl's $DB::sub variable. See | |
374 | C<PL_DBsingle>. | |
375 | ||
376 | GV * PL_DBsub | |
377 | ||
378 | =for hackers | |
379 | Found in file intrpvar.h | |
380 | ||
381 | =item PL_DBtrace | |
d8c40edc | 382 | X<PL_DBtrace> |
2eb25c99 JH |
383 | |
384 | Trace variable used when Perl is run in debugging mode, with the B<-d> | |
385 | switch. This is the C variable which corresponds to Perl's $DB::trace | |
386 | variable. See C<PL_DBsingle>. | |
387 | ||
388 | SV * PL_DBtrace | |
389 | ||
390 | =for hackers | |
391 | Found in file intrpvar.h | |
392 | ||
393 | =item PL_dowarn | |
d8c40edc | 394 | X<PL_dowarn> |
2eb25c99 JH |
395 | |
396 | The C variable which corresponds to Perl's $^W warning variable. | |
397 | ||
398 | bool PL_dowarn | |
399 | ||
400 | =for hackers | |
401 | Found in file intrpvar.h | |
402 | ||
403 | =item PL_last_in_gv | |
d8c40edc | 404 | X<PL_last_in_gv> |
2eb25c99 JH |
405 | |
406 | The GV which was last used for a filehandle input operation. (C<< <FH> >>) | |
407 | ||
408 | GV* PL_last_in_gv | |
409 | ||
410 | =for hackers | |
411 | Found in file thrdvar.h | |
412 | ||
413 | =item PL_ofs_sv | |
d8c40edc | 414 | X<PL_ofs_sv> |
2eb25c99 JH |
415 | |
416 | The output field separator - C<$,> in Perl space. | |
417 | ||
418 | SV* PL_ofs_sv | |
419 | ||
420 | =for hackers | |
421 | Found in file thrdvar.h | |
422 | ||
423 | =item PL_rs | |
d8c40edc | 424 | X<PL_rs> |
2eb25c99 JH |
425 | |
426 | The input record separator - C<$/> in Perl space. | |
427 | ||
428 | SV* PL_rs | |
429 | ||
430 | =for hackers | |
431 | Found in file thrdvar.h | |
432 | ||
645c22ef | 433 | |
a4f1a029 | 434 | =back |
645c22ef | 435 | |
a4f1a029 NIS |
436 | =head1 GV Functions |
437 | ||
438 | =over 8 | |
439 | ||
440 | =item is_gv_magical | |
d8c40edc | 441 | X<is_gv_magical> |
a4f1a029 NIS |
442 | |
443 | Returns C<TRUE> if given the name of a magical GV. | |
444 | ||
445 | Currently only useful internally when determining if a GV should be | |
446 | created even in rvalue contexts. | |
447 | ||
448 | C<flags> is not used at present but available for future extension to | |
449 | allow selecting particular classes of magical variable. | |
450 | ||
766f8916 MHM |
451 | Currently assumes that C<name> is NUL terminated (as well as len being valid). |
452 | This assumption is met by all callers within the perl core, which all pass | |
453 | pointers returned by SvPV. | |
454 | ||
7fc63493 AL |
455 | bool is_gv_magical(const char *name, STRLEN len, U32 flags) |
456 | ||
457 | =for hackers | |
458 | Found in file gv.c | |
459 | ||
460 | =item is_gv_magical_sv | |
d8c40edc | 461 | X<is_gv_magical_sv> |
7fc63493 AL |
462 | |
463 | Returns C<TRUE> if given the name of a magical GV. Calls is_gv_magical. | |
464 | ||
465 | bool is_gv_magical_sv(SV *name, U32 flags) | |
645c22ef DM |
466 | |
467 | =for hackers | |
a4f1a029 NIS |
468 | Found in file gv.c |
469 | ||
470 | ||
471 | =back | |
472 | ||
b3ca2e83 NC |
473 | =head1 Hash Manipulation Functions |
474 | ||
475 | =over 8 | |
476 | ||
477 | =item refcounted_he_chain_2hv | |
478 | X<refcounted_he_chain_2hv> | |
479 | ||
480 | Generates an returns a C<HV *> by walking up the tree starting at the passed | |
481 | in C<struct refcounted_he *>. | |
482 | ||
483 | HV * refcounted_he_chain_2hv(const struct refcounted_he *c) | |
484 | ||
485 | =for hackers | |
486 | Found in file hv.c | |
487 | ||
a24d89c9 NC |
488 | =item refcounted_he_copy |
489 | X<refcounted_he_copy> | |
490 | ||
491 | Copies a chain of C<struct refcounted_he *>. Used by C<pp_entereval>. | |
492 | ||
493 | struct refcounted_he * refcounted_he_copy(const struct refcounted_he *he) | |
494 | ||
495 | =for hackers | |
496 | Found in file hv.c | |
497 | ||
b3ca2e83 NC |
498 | =item refcounted_he_dup |
499 | X<refcounted_he_dup> | |
500 | ||
501 | Duplicates the C<struct refcounted_he *> for a new thread. | |
502 | ||
503 | struct refcounted_he * refcounted_he_dup(const struct refcounted_he *const he, CLONE_PARAMS* param) | |
504 | ||
505 | =for hackers | |
506 | Found in file hv.c | |
507 | ||
508 | =item refcounted_he_free | |
509 | X<refcounted_he_free> | |
510 | ||
511 | Decrements the reference count of the passed in C<struct refcounted_he *> | |
512 | by one. If the reference count reaches zero the structure's memory is freed, | |
513 | and C<refcounted_he_free> iterates onto the parent node. | |
514 | ||
515 | void refcounted_he_free(struct refcounted_he *he) | |
516 | ||
517 | =for hackers | |
518 | Found in file hv.c | |
519 | ||
520 | =item refcounted_he_new | |
521 | X<refcounted_he_new> | |
522 | ||
523 | Creates a new C<struct refcounted_he>. Assumes ownership of one reference | |
524 | to I<value>. As S<key> is copied into a shared hash key, all references remain | |
525 | the property of the caller. The C<struct refcounted_he> is returned with a | |
526 | reference count of 1. | |
527 | ||
b46c265e | 528 | struct refcounted_he * refcounted_he_new(struct refcounted_he *const parent, SV *const key, SV *const value) |
b3ca2e83 NC |
529 | |
530 | =for hackers | |
531 | Found in file hv.c | |
532 | ||
533 | ||
534 | =back | |
535 | ||
a4f1a029 NIS |
536 | =head1 IO Functions |
537 | ||
538 | =over 8 | |
645c22ef | 539 | |
a8586c98 | 540 | =item start_glob |
d8c40edc | 541 | X<start_glob> |
a8586c98 JH |
542 | |
543 | Function called by C<do_readline> to spawn a glob (or do the glob inside | |
544 | perl on VMS). This code used to be inline, but now perl uses C<File::Glob> | |
bd16a5f0 | 545 | this glob starter is only used by miniperl during the build process. |
a8586c98 JH |
546 | Moving it away shrinks pp_hot.c; shrinking pp_hot.c helps speed perl up. |
547 | ||
548 | PerlIO* start_glob(SV* pattern, IO *io) | |
549 | ||
550 | =for hackers | |
551 | Found in file doio.c | |
552 | ||
a4f1a029 NIS |
553 | |
554 | =back | |
555 | ||
0cbee0a4 DM |
556 | =head1 Magical Functions |
557 | ||
558 | =over 8 | |
559 | ||
b3ca2e83 NC |
560 | =item magic_sethint |
561 | X<magic_sethint> | |
562 | ||
563 | Triggered by a delete from %^H, records the key to C<PL_compiling.cop_hints>. | |
564 | ||
565 | int magic_sethint(SV* sv, MAGIC* mg) | |
566 | ||
567 | =for hackers | |
568 | Found in file mg.c | |
569 | ||
0cbee0a4 | 570 | =item mg_localize |
d8c40edc | 571 | X<mg_localize> |
0cbee0a4 DM |
572 | |
573 | Copy some of the magic from an existing SV to new localized version of | |
574 | that SV. Container magic (eg %ENV, $1, tie) gets copied, value magic | |
575 | doesn't (eg taint, pos). | |
576 | ||
577 | void mg_localize(SV* sv, SV* nsv) | |
578 | ||
579 | =for hackers | |
580 | Found in file mg.c | |
581 | ||
582 | ||
583 | =back | |
584 | ||
a4f1a029 NIS |
585 | =head1 Pad Data Structures |
586 | ||
587 | =over 8 | |
588 | ||
589 | =item CvPADLIST | |
d8c40edc | 590 | X<CvPADLIST> |
a4f1a029 NIS |
591 | |
592 | CV's can have CvPADLIST(cv) set to point to an AV. | |
593 | ||
594 | For these purposes "forms" are a kind-of CV, eval""s are too (except they're | |
595 | not callable at will and are always thrown away after the eval"" is done | |
b5c19bd7 DM |
596 | executing). Require'd files are simply evals without any outer lexical |
597 | scope. | |
a4f1a029 NIS |
598 | |
599 | XSUBs don't have CvPADLIST set - dXSTARG fetches values from PL_curpad, | |
600 | but that is really the callers pad (a slot of which is allocated by | |
601 | every entersub). | |
602 | ||
603 | The CvPADLIST AV has does not have AvREAL set, so REFCNT of component items | |
f3548bdc | 604 | is managed "manual" (mostly in pad.c) rather than normal av.c rules. |
a4f1a029 NIS |
605 | The items in the AV are not SVs as for a normal AV, but other AVs: |
606 | ||
607 | 0'th Entry of the CvPADLIST is an AV which represents the "names" or rather | |
608 | the "static type information" for lexicals. | |
609 | ||
610 | The CvDEPTH'th entry of CvPADLIST AV is an AV which is the stack frame at that | |
611 | depth of recursion into the CV. | |
612 | The 0'th slot of a frame AV is an AV which is @_. | |
613 | other entries are storage for variables and op targets. | |
614 | ||
615 | During compilation: | |
a6d05634 TM |
616 | C<PL_comppad_name> is set to the names AV. |
617 | C<PL_comppad> is set to the frame AV for the frame CvDEPTH == 1. | |
618 | C<PL_curpad> is set to the body of the frame AV (i.e. AvARRAY(PL_comppad)). | |
a4f1a029 | 619 | |
f3548bdc DM |
620 | During execution, C<PL_comppad> and C<PL_curpad> refer to the live |
621 | frame of the currently executing sub. | |
622 | ||
623 | Iterating over the names AV iterates over all possible pad | |
a4f1a029 NIS |
624 | items. Pad slots that are SVs_PADTMP (targets/GVs/constants) end up having |
625 | &PL_sv_undef "names" (see pad_alloc()). | |
626 | ||
627 | Only my/our variable (SVs_PADMY/SVs_PADOUR) slots get valid names. | |
628 | The rest are op targets/GVs/constants which are statically allocated | |
629 | or resolved at compile time. These don't have names by which they | |
630 | can be looked up from Perl code at run time through eval"" like | |
631 | my/our variables can be. Since they can't be looked up by "name" | |
632 | but only by their index allocated at compile time (which is usually | |
633 | in PL_op->op_targ), wasting a name SV for them doesn't make sense. | |
634 | ||
635 | The SVs in the names AV have their PV being the name of the variable. | |
dd2155a4 DM |
636 | NV+1..IV inclusive is a range of cop_seq numbers for which the name is |
637 | valid. For typed lexicals name SV is SVt_PVMG and SvSTASH points at the | |
b37c2d43 AL |
638 | type. For C<our> lexicals, the type is also SVt_PVGV, with the MAGIC slot |
639 | pointing at the stash of the associated global (so that duplicate C<our> | |
640 | declarations in the same package can be detected). SvCUR is sometimes | |
641 | hijacked to store the generation number during compilation. | |
a4f1a029 | 642 | |
b5c19bd7 DM |
643 | If SvFAKE is set on the name SV, then that slot in the frame AV is |
644 | a REFCNT'ed reference to a lexical from "outside". In this case, | |
645 | the name SV does not use NVX and IVX to store a cop_seq range, since it is | |
646 | in scope throughout. Instead IVX stores some flags containing info about | |
647 | the real lexical (is it declared in an anon, and is it capable of being | |
648 | instantiated multiple times?), and for fake ANONs, NVX contains the index | |
649 | within the parent's pad where the lexical's value is stored, to make | |
650 | cloning quicker. | |
a4f1a029 | 651 | |
a6d05634 | 652 | If the 'name' is '&' the corresponding entry in frame AV |
a4f1a029 NIS |
653 | is a CV representing a possible closure. |
654 | (SvFAKE and name of '&' is not a meaningful combination currently but could | |
655 | become so if C<my sub foo {}> is implemented.) | |
656 | ||
5c3943b6 RGS |
657 | Note that formats are treated as anon subs, and are cloned each time |
658 | write is called (if necessary). | |
659 | ||
2814eb74 PJ |
660 | The flag SVf_PADSTALE is cleared on lexicals each time the my() is executed, |
661 | and set on scope exit. This allows the 'Variable $x is not available' warning | |
662 | to be generated in evals, such as | |
663 | ||
664 | { my $x = 1; sub f { eval '$x'} } f(); | |
665 | ||
a4f1a029 NIS |
666 | AV * CvPADLIST(CV *cv) |
667 | ||
668 | =for hackers | |
dd2155a4 DM |
669 | Found in file pad.c |
670 | ||
671 | =item cv_clone | |
d8c40edc | 672 | X<cv_clone> |
dd2155a4 DM |
673 | |
674 | Clone a CV: make a new CV which points to the same code etc, but which | |
ad63d80f | 675 | has a newly-created pad built by copying the prototype pad and capturing |
dd2155a4 DM |
676 | any outer lexicals. |
677 | ||
678 | CV* cv_clone(CV* proto) | |
679 | ||
680 | =for hackers | |
681 | Found in file pad.c | |
682 | ||
683 | =item cv_dump | |
d8c40edc | 684 | X<cv_dump> |
dd2155a4 DM |
685 | |
686 | dump the contents of a CV | |
687 | ||
e1ec3a88 | 688 | void cv_dump(const CV *cv, const char *title) |
dd2155a4 DM |
689 | |
690 | =for hackers | |
691 | Found in file pad.c | |
692 | ||
693 | =item do_dump_pad | |
d8c40edc | 694 | X<do_dump_pad> |
dd2155a4 DM |
695 | |
696 | Dump the contents of a padlist | |
697 | ||
698 | void do_dump_pad(I32 level, PerlIO *file, PADLIST *padlist, int full) | |
699 | ||
700 | =for hackers | |
701 | Found in file pad.c | |
702 | ||
703 | =item intro_my | |
d8c40edc | 704 | X<intro_my> |
dd2155a4 DM |
705 | |
706 | "Introduce" my variables to visible status. | |
707 | ||
708 | U32 intro_my() | |
709 | ||
710 | =for hackers | |
711 | Found in file pad.c | |
712 | ||
713 | =item pad_add_anon | |
d8c40edc | 714 | X<pad_add_anon> |
dd2155a4 DM |
715 | |
716 | Add an anon code entry to the current compiling pad | |
717 | ||
718 | PADOFFSET pad_add_anon(SV* sv, OPCODE op_type) | |
719 | ||
720 | =for hackers | |
721 | Found in file pad.c | |
722 | ||
723 | =item pad_add_name | |
d8c40edc | 724 | X<pad_add_name> |
dd2155a4 | 725 | |
b5c19bd7 DM |
726 | Create a new name and associated PADMY SV in the current pad; return the |
727 | offset. | |
dd2155a4 DM |
728 | If C<typestash> is valid, the name is for a typed lexical; set the |
729 | name's stash to that value. | |
730 | If C<ourstash> is valid, it's an our lexical, set the name's | |
b37c2d43 | 731 | OURSTASH to that value |
dd2155a4 | 732 | |
dd2155a4 DM |
733 | If fake, it means we're cloning an existing entry |
734 | ||
e1ec3a88 | 735 | PADOFFSET pad_add_name(const char *name, HV* typestash, HV* ourstash, bool clone) |
dd2155a4 DM |
736 | |
737 | =for hackers | |
738 | Found in file pad.c | |
739 | ||
740 | =item pad_alloc | |
d8c40edc | 741 | X<pad_alloc> |
dd2155a4 DM |
742 | |
743 | Allocate a new my or tmp pad entry. For a my, simply push a null SV onto | |
744 | the end of PL_comppad, but for a tmp, scan the pad from PL_padix upwards | |
324092c6 | 745 | for a slot which has no name and no active value. |
dd2155a4 DM |
746 | |
747 | PADOFFSET pad_alloc(I32 optype, U32 tmptype) | |
748 | ||
749 | =for hackers | |
750 | Found in file pad.c | |
751 | ||
752 | =item pad_block_start | |
d8c40edc | 753 | X<pad_block_start> |
dd2155a4 DM |
754 | |
755 | Update the pad compilation state variables on entry to a new block | |
756 | ||
757 | void pad_block_start(int full) | |
758 | ||
759 | =for hackers | |
760 | Found in file pad.c | |
761 | ||
762 | =item pad_check_dup | |
d8c40edc | 763 | X<pad_check_dup> |
dd2155a4 DM |
764 | |
765 | Check for duplicate declarations: report any of: | |
766 | * a my in the current scope with the same name; | |
767 | * an our (anywhere in the pad) with the same name and the same stash | |
768 | as C<ourstash> | |
769 | C<is_our> indicates that the name to check is an 'our' declaration | |
770 | ||
e1ec3a88 | 771 | void pad_check_dup(const char* name, bool is_our, const HV* ourstash) |
dd2155a4 DM |
772 | |
773 | =for hackers | |
774 | Found in file pad.c | |
775 | ||
776 | =item pad_findlex | |
d8c40edc | 777 | X<pad_findlex> |
dd2155a4 DM |
778 | |
779 | Find a named lexical anywhere in a chain of nested pads. Add fake entries | |
b5c19bd7 DM |
780 | in the inner pads if it's found in an outer one. |
781 | ||
782 | Returns the offset in the bottom pad of the lex or the fake lex. | |
783 | cv is the CV in which to start the search, and seq is the current cop_seq | |
784 | to match against. If warn is true, print appropriate warnings. The out_* | |
785 | vars return values, and so are pointers to where the returned values | |
786 | should be stored. out_capture, if non-null, requests that the innermost | |
787 | instance of the lexical is captured; out_name_sv is set to the innermost | |
788 | matched namesv or fake namesv; out_flags returns the flags normally | |
789 | associated with the IVX field of a fake namesv. | |
790 | ||
791 | Note that pad_findlex() is recursive; it recurses up the chain of CVs, | |
792 | then comes back down, adding fake entries as it goes. It has to be this way | |
793 | because fake namesvs in anon protoypes have to store in NVX the index into | |
794 | the parent pad. | |
795 | ||
e1ec3a88 | 796 | PADOFFSET pad_findlex(const char *name, const CV* cv, U32 seq, int warn, SV** out_capture, SV** out_name_sv, int *out_flags) |
dd2155a4 DM |
797 | |
798 | =for hackers | |
799 | Found in file pad.c | |
800 | ||
801 | =item pad_findmy | |
d8c40edc | 802 | X<pad_findmy> |
dd2155a4 | 803 | |
ad63d80f | 804 | Given a lexical name, try to find its offset, first in the current pad, |
dd2155a4 | 805 | or failing that, in the pads of any lexically enclosing subs (including |
ad63d80f JP |
806 | the complications introduced by eval). If the name is found in an outer pad, |
807 | then a fake entry is added to the current pad. | |
dd2155a4 DM |
808 | Returns the offset in the current pad, or NOT_IN_PAD on failure. |
809 | ||
e1ec3a88 | 810 | PADOFFSET pad_findmy(const char* name) |
dd2155a4 DM |
811 | |
812 | =for hackers | |
813 | Found in file pad.c | |
814 | ||
815 | =item pad_fixup_inner_anons | |
d8c40edc | 816 | X<pad_fixup_inner_anons> |
dd2155a4 DM |
817 | |
818 | For any anon CVs in the pad, change CvOUTSIDE of that CV from | |
7dafbf52 DM |
819 | old_cv to new_cv if necessary. Needed when a newly-compiled CV has to be |
820 | moved to a pre-existing CV struct. | |
dd2155a4 DM |
821 | |
822 | void pad_fixup_inner_anons(PADLIST *padlist, CV *old_cv, CV *new_cv) | |
823 | ||
824 | =for hackers | |
825 | Found in file pad.c | |
826 | ||
827 | =item pad_free | |
d8c40edc | 828 | X<pad_free> |
dd2155a4 | 829 | |
d7f8936a | 830 | Free the SV at offset po in the current pad. |
dd2155a4 DM |
831 | |
832 | void pad_free(PADOFFSET po) | |
833 | ||
834 | =for hackers | |
835 | Found in file pad.c | |
836 | ||
837 | =item pad_leavemy | |
d8c40edc | 838 | X<pad_leavemy> |
dd2155a4 DM |
839 | |
840 | Cleanup at end of scope during compilation: set the max seq number for | |
841 | lexicals in this scope and warn of any lexicals that never got introduced. | |
842 | ||
843 | void pad_leavemy() | |
844 | ||
845 | =for hackers | |
846 | Found in file pad.c | |
847 | ||
848 | =item pad_new | |
d8c40edc | 849 | X<pad_new> |
dd2155a4 | 850 | |
ad63d80f | 851 | Create a new compiling padlist, saving and updating the various global |
dd2155a4 DM |
852 | vars at the same time as creating the pad itself. The following flags |
853 | can be OR'ed together: | |
854 | ||
855 | padnew_CLONE this pad is for a cloned CV | |
856 | padnew_SAVE save old globals | |
857 | padnew_SAVESUB also save extra stuff for start of sub | |
858 | ||
c7c737cb | 859 | PADLIST* pad_new(int flags) |
dd2155a4 DM |
860 | |
861 | =for hackers | |
862 | Found in file pad.c | |
863 | ||
864 | =item pad_push | |
d8c40edc | 865 | X<pad_push> |
dd2155a4 DM |
866 | |
867 | Push a new pad frame onto the padlist, unless there's already a pad at | |
26019298 AL |
868 | this depth, in which case don't bother creating a new one. Then give |
869 | the new pad an @_ in slot zero. | |
dd2155a4 | 870 | |
26019298 | 871 | void pad_push(PADLIST *padlist, int depth) |
dd2155a4 DM |
872 | |
873 | =for hackers | |
874 | Found in file pad.c | |
875 | ||
876 | =item pad_reset | |
d8c40edc | 877 | X<pad_reset> |
dd2155a4 DM |
878 | |
879 | Mark all the current temporaries for reuse | |
880 | ||
881 | void pad_reset() | |
882 | ||
883 | =for hackers | |
884 | Found in file pad.c | |
885 | ||
886 | =item pad_setsv | |
d8c40edc | 887 | X<pad_setsv> |
dd2155a4 DM |
888 | |
889 | Set the entry at offset po in the current pad to sv. | |
890 | Use the macro PAD_SETSV() rather than calling this function directly. | |
891 | ||
892 | void pad_setsv(PADOFFSET po, SV* sv) | |
893 | ||
894 | =for hackers | |
895 | Found in file pad.c | |
896 | ||
897 | =item pad_swipe | |
d8c40edc | 898 | X<pad_swipe> |
dd2155a4 DM |
899 | |
900 | Abandon the tmp in the current pad at offset po and replace with a | |
901 | new one. | |
902 | ||
903 | void pad_swipe(PADOFFSET po, bool refadjust) | |
904 | ||
905 | =for hackers | |
906 | Found in file pad.c | |
907 | ||
908 | =item pad_tidy | |
d8c40edc | 909 | X<pad_tidy> |
dd2155a4 DM |
910 | |
911 | Tidy up a pad after we've finished compiling it: | |
912 | * remove most stuff from the pads of anonsub prototypes; | |
913 | * give it a @_; | |
914 | * mark tmps as such. | |
915 | ||
916 | void pad_tidy(padtidy_type type) | |
917 | ||
918 | =for hackers | |
919 | Found in file pad.c | |
920 | ||
921 | =item pad_undef | |
d8c40edc | 922 | X<pad_undef> |
dd2155a4 DM |
923 | |
924 | Free the padlist associated with a CV. | |
925 | If parts of it happen to be current, we null the relevant | |
926 | PL_*pad* global vars so that we don't have any dangling references left. | |
927 | We also repoint the CvOUTSIDE of any about-to-be-orphaned | |
a3985cdc | 928 | inner subs to the outer of this cv. |
dd2155a4 | 929 | |
7dafbf52 DM |
930 | (This function should really be called pad_free, but the name was already |
931 | taken) | |
932 | ||
a3985cdc | 933 | void pad_undef(CV* cv) |
dd2155a4 DM |
934 | |
935 | =for hackers | |
936 | Found in file pad.c | |
a4f1a029 NIS |
937 | |
938 | ||
939 | =back | |
940 | ||
941 | =head1 Stack Manipulation Macros | |
942 | ||
943 | =over 8 | |
944 | ||
945 | =item djSP | |
d8c40edc | 946 | X<djSP> |
a4f1a029 NIS |
947 | |
948 | Declare Just C<SP>. This is actually identical to C<dSP>, and declares | |
949 | a local copy of perl's stack pointer, available via the C<SP> macro. | |
950 | See C<SP>. (Available for backward source code compatibility with the | |
951 | old (Perl 5.005) thread model.) | |
952 | ||
953 | djSP; | |
954 | ||
955 | =for hackers | |
956 | Found in file pp.h | |
957 | ||
958 | =item LVRET | |
d8c40edc | 959 | X<LVRET> |
a4f1a029 NIS |
960 | |
961 | True if this op will be the return value of an lvalue subroutine | |
962 | ||
963 | =for hackers | |
964 | Found in file pp.h | |
965 | ||
966 | ||
967 | =back | |
968 | ||
969 | =head1 SV Manipulation Functions | |
970 | ||
971 | =over 8 | |
972 | ||
645c22ef | 973 | =item sv_add_arena |
d8c40edc | 974 | X<sv_add_arena> |
645c22ef DM |
975 | |
976 | Given a chunk of memory, link it to the head of the list of arenas, | |
977 | and split it into a list of free SVs. | |
978 | ||
979 | void sv_add_arena(char* ptr, U32 size, U32 flags) | |
980 | ||
981 | =for hackers | |
982 | Found in file sv.c | |
983 | ||
984 | =item sv_clean_all | |
d8c40edc | 985 | X<sv_clean_all> |
645c22ef DM |
986 | |
987 | Decrement the refcnt of each remaining SV, possibly triggering a | |
988 | cleanup. This function may have to be called multiple times to free | |
8fb26106 | 989 | SVs which are in complex self-referential hierarchies. |
645c22ef DM |
990 | |
991 | I32 sv_clean_all() | |
992 | ||
993 | =for hackers | |
994 | Found in file sv.c | |
995 | ||
996 | =item sv_clean_objs | |
d8c40edc | 997 | X<sv_clean_objs> |
645c22ef DM |
998 | |
999 | Attempt to destroy all objects not yet freed | |
1000 | ||
1001 | void sv_clean_objs() | |
1002 | ||
1003 | =for hackers | |
1004 | Found in file sv.c | |
1005 | ||
1006 | =item sv_free_arenas | |
d8c40edc | 1007 | X<sv_free_arenas> |
645c22ef DM |
1008 | |
1009 | Deallocate the memory used by all arenas. Note that all the individual SV | |
1010 | heads and bodies within the arenas must already have been freed. | |
1011 | ||
1012 | void sv_free_arenas() | |
1013 | ||
1014 | =for hackers | |
1015 | Found in file sv.c | |
1016 | ||
a4f1a029 | 1017 | |
954c1994 GS |
1018 | =back |
1019 | ||
979f2922 TS |
1020 | =head1 Unicode Support |
1021 | ||
1022 | =over 8 | |
1023 | ||
1024 | =item find_uninit_var | |
1025 | X<find_uninit_var> | |
1026 | ||
1027 | Find the name of the undefined variable (if any) that caused the operator o | |
1028 | to issue a "Use of uninitialized value" warning. | |
1029 | If match is true, only return a name if it's value matches uninit_sv. | |
1030 | So roughly speaking, if a unary operator (such as OP_COS) generates a | |
1031 | warning, then following the direct child of the op may yield an | |
1032 | OP_PADSV or OP_GV that gives the name of the undefined variable. On the | |
1033 | other hand, with OP_ADD there are two branches to follow, so we only print | |
1034 | the variable name if we get an exact match. | |
1035 | ||
1036 | The name is returned as a mortal SV. | |
1037 | ||
1038 | Assumes that PL_op is the op that originally triggered the error, and that | |
1039 | PL_comppad/PL_curpad points to the currently executing pad. | |
1040 | ||
1041 | SV* find_uninit_var(OP* obase, SV* uninit_sv, bool top) | |
1042 | ||
1043 | =for hackers | |
1044 | Found in file sv.c | |
1045 | ||
1046 | =item report_uninit | |
1047 | X<report_uninit> | |
1048 | ||
1049 | Print appropriate "Use of uninitialized variable" warning | |
1050 | ||
1051 | void report_uninit(SV* uninit_sv) | |
1052 | ||
1053 | =for hackers | |
1054 | Found in file sv.c | |
1055 | ||
1056 | ||
1057 | =back | |
1058 | ||
954c1994 GS |
1059 | =head1 AUTHORS |
1060 | ||
1c846c1f NIS |
1061 | The autodocumentation system was originally added to the Perl core by |
1062 | Benjamin Stuhl. Documentation is by whoever was kind enough to | |
954c1994 GS |
1063 | document their functions. |
1064 | ||
1065 | =head1 SEE ALSO | |
1066 | ||
1067 | perlguts(1), perlapi(1) | |
1068 |