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1 | =head1 NAME |
2 | |
3 | perlguts - Perl's Internal Functions |
4 | |
5 | =head1 DESCRIPTION |
6 | |
7 | This document attempts to describe some of the internal functions of the |
8 | Perl executable. It is far from complete and probably contains many errors. |
9 | Please refer any questions or comments to the author below. |
10 | |
11 | =head1 Datatypes |
12 | |
13 | Perl has three typedefs that handle Perl's three main data types: |
14 | |
15 | SV Scalar Value |
16 | AV Array Value |
17 | HV Hash Value |
18 | |
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19 | Each typedef has specific routines that manipulate the various data types. |
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20 | |
21 | =head2 What is an "IV"? |
22 | |
23 | Perl uses a special typedef IV which is large enough to hold either an |
24 | integer or a pointer. |
25 | |
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26 | Perl also uses two special typedefs, I32 and I16, which will always be at |
27 | least 32-bits and 16-bits long, respectively. |
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28 | |
29 | =head2 Working with SV's |
30 | |
31 | An SV can be created and loaded with one command. There are four types of |
32 | values that can be loaded: an integer value (IV), a double (NV), a string, |
33 | (PV), and another scalar (SV). |
34 | |
35 | The four routines are: |
36 | |
37 | SV* newSViv(IV); |
38 | SV* newSVnv(double); |
39 | SV* newSVpv(char*, int); |
40 | SV* newSVsv(SV*); |
41 | |
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42 | To change the value of an I<already-existing> SV, there are five routines: |
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43 | |
44 | void sv_setiv(SV*, IV); |
45 | void sv_setnv(SV*, double); |
46 | void sv_setpvn(SV*, char*, int) |
47 | void sv_setpv(SV*, char*); |
48 | void sv_setsv(SV*, SV*); |
49 | |
50 | Notice that you can choose to specify the length of the string to be |
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51 | assigned by using C<sv_setpvn> or C<newSVpv>, or you may allow Perl to |
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52 | calculate the length by using C<sv_setpv> or by specifying 0 as the second |
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53 | argument to C<newSVpv>. Be warned, though, that Perl will determine the |
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54 | string's length by using C<strlen>, which depends on the string terminating |
55 | with a NUL character. |
56 | |
57 | To access the actual value that an SV points to, you can use the macros: |
58 | |
59 | SvIV(SV*) |
60 | SvNV(SV*) |
61 | SvPV(SV*, STRLEN len) |
62 | |
63 | which will automatically coerce the actual scalar type into an IV, double, |
64 | or string. |
65 | |
66 | In the C<SvPV> macro, the length of the string returned is placed into the |
67 | variable C<len> (this is a macro, so you do I<not> use C<&len>). If you do not |
68 | care what the length of the data is, use the global variable C<na>. Remember, |
69 | however, that Perl allows arbitrary strings of data that may both contain |
70 | NUL's and not be terminated by a NUL. |
71 | |
72 | If you simply want to know if the scalar value is TRUE, you can use: |
73 | |
74 | SvTRUE(SV*) |
75 | |
76 | Although Perl will automatically grow strings for you, if you need to force |
77 | Perl to allocate more memory for your SV, you can use the macro |
78 | |
79 | SvGROW(SV*, STRLEN newlen) |
80 | |
81 | which will determine if more memory needs to be allocated. If so, it will |
82 | call the function C<sv_grow>. Note that C<SvGROW> can only increase, not |
83 | decrease, the allocated memory of an SV. |
84 | |
85 | If you have an SV and want to know what kind of data Perl thinks is stored |
86 | in it, you can use the following macros to check the type of SV you have. |
87 | |
88 | SvIOK(SV*) |
89 | SvNOK(SV*) |
90 | SvPOK(SV*) |
91 | |
92 | You can get and set the current length of the string stored in an SV with |
93 | the following macros: |
94 | |
95 | SvCUR(SV*) |
96 | SvCUR_set(SV*, I32 val) |
97 | |
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98 | You can also get a pointer to the end of the string stored in the SV |
99 | with the macro: |
100 | |
101 | SvEND(SV*) |
102 | |
103 | But note that these last three macros are valid only if C<SvPOK()> is true. |
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104 | |
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105 | If you want to append something to the end of string stored in an C<SV*>, |
106 | you can use the following functions: |
107 | |
108 | void sv_catpv(SV*, char*); |
109 | void sv_catpvn(SV*, char*, int); |
110 | void sv_catsv(SV*, SV*); |
111 | |
112 | The first function calculates the length of the string to be appended by |
113 | using C<strlen>. In the second, you specify the length of the string |
114 | yourself. The third function extends the string stored in the first SV |
115 | with the string stored in the second SV. It also forces the second SV to |
116 | be interpreted as a string. |
117 | |
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118 | If you know the name of a scalar variable, you can get a pointer to its SV |
119 | by using the following: |
120 | |
121 | SV* perl_get_sv("varname", FALSE); |
122 | |
123 | This returns NULL if the variable does not exist. |
124 | |
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125 | If you want to know if this variable (or any other SV) is actually C<defined>, |
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126 | you can call: |
127 | |
128 | SvOK(SV*) |
129 | |
130 | The scalar C<undef> value is stored in an SV instance called C<sv_undef>. Its |
131 | address can be used whenever an C<SV*> is needed. |
132 | |
133 | There are also the two values C<sv_yes> and C<sv_no>, which contain Boolean |
134 | TRUE and FALSE values, respectively. Like C<sv_undef>, their addresses can |
135 | be used whenever an C<SV*> is needed. |
136 | |
137 | Do not be fooled into thinking that C<(SV *) 0> is the same as C<&sv_undef>. |
138 | Take this code: |
139 | |
140 | SV* sv = (SV*) 0; |
141 | if (I-am-to-return-a-real-value) { |
142 | sv = sv_2mortal(newSViv(42)); |
143 | } |
144 | sv_setsv(ST(0), sv); |
145 | |
146 | This code tries to return a new SV (which contains the value 42) if it should |
147 | return a real value, or undef otherwise. Instead it has returned a null |
148 | pointer which, somewhere down the line, will cause a segmentation violation, |
149 | or just weird results. Change the zero to C<&sv_undef> in the first line and |
150 | all will be well. |
151 | |
152 | To free an SV that you've created, call C<SvREFCNT_dec(SV*)>. Normally this |
153 | call is not necessary. See the section on B<MORTALITY>. |
154 | |
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155 | =head2 What's Really Stored in an SV? |
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156 | |
157 | Recall that the usual method of determining the type of scalar you have is |
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158 | to use C<Sv*OK> macros. Since a scalar can be both a number and a string, |
159 | usually these macros will always return TRUE and calling the C<Sv*V> |
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160 | macros will do the appropriate conversion of string to integer/double or |
161 | integer/double to string. |
162 | |
163 | If you I<really> need to know if you have an integer, double, or string |
164 | pointer in an SV, you can use the following three macros instead: |
165 | |
166 | SvIOKp(SV*) |
167 | SvNOKp(SV*) |
168 | SvPOKp(SV*) |
169 | |
170 | These will tell you if you truly have an integer, double, or string pointer |
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171 | stored in your SV. The "p" stands for private. |
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172 | |
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173 | In general, though, it's best to just use the C<Sv*V> macros. |
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174 | |
175 | =head2 Working with AV's |
176 | |
177 | There are two ways to create and load an AV. The first method just creates |
178 | an empty AV: |
179 | |
180 | AV* newAV(); |
181 | |
182 | The second method both creates the AV and initially populates it with SV's: |
183 | |
184 | AV* av_make(I32 num, SV **ptr); |
185 | |
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186 | The second argument points to an array containing C<num> C<SV*>'s. Once the |
187 | AV has been created, the SV's can be destroyed, if so desired. |
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188 | |
189 | Once the AV has been created, the following operations are possible on AV's: |
190 | |
191 | void av_push(AV*, SV*); |
192 | SV* av_pop(AV*); |
193 | SV* av_shift(AV*); |
194 | void av_unshift(AV*, I32 num); |
195 | |
196 | These should be familiar operations, with the exception of C<av_unshift>. |
197 | This routine adds C<num> elements at the front of the array with the C<undef> |
198 | value. You must then use C<av_store> (described below) to assign values |
199 | to these new elements. |
200 | |
201 | Here are some other functions: |
202 | |
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203 | I32 av_len(AV*); /* Returns highest index value in array */ |
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204 | |
205 | SV** av_fetch(AV*, I32 key, I32 lval); |
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206 | /* Fetches value at key offset, but it stores an undef value |
207 | at the offset if lval is non-zero */ |
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208 | SV** av_store(AV*, I32 key, SV* val); |
209 | /* Stores val at offset key */ |
210 | |
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211 | Take note that C<av_fetch> and C<av_store> return C<SV**>'s, not C<SV*>'s. |
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212 | |
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213 | void av_clear(AV*); |
214 | /* Clear out all elements, but leave the array */ |
215 | void av_undef(AV*); |
216 | /* Undefines the array, removing all elements */ |
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217 | void av_extend(AV*, I32 key); |
218 | /* Extend the array to a total of key elements */ |
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219 | |
220 | If you know the name of an array variable, you can get a pointer to its AV |
221 | by using the following: |
222 | |
223 | AV* perl_get_av("varname", FALSE); |
224 | |
225 | This returns NULL if the variable does not exist. |
226 | |
227 | =head2 Working with HV's |
228 | |
229 | To create an HV, you use the following routine: |
230 | |
231 | HV* newHV(); |
232 | |
233 | Once the HV has been created, the following operations are possible on HV's: |
234 | |
235 | SV** hv_store(HV*, char* key, U32 klen, SV* val, U32 hash); |
236 | SV** hv_fetch(HV*, char* key, U32 klen, I32 lval); |
237 | |
238 | The C<klen> parameter is the length of the key being passed in. The C<val> |
239 | argument contains the SV pointer to the scalar being stored, and C<hash> is |
240 | the pre-computed hash value (zero if you want C<hv_store> to calculate it |
241 | for you). The C<lval> parameter indicates whether this fetch is actually a |
242 | part of a store operation. |
243 | |
244 | Remember that C<hv_store> and C<hv_fetch> return C<SV**>'s and not just |
245 | C<SV*>. In order to access the scalar value, you must first dereference |
246 | the return value. However, you should check to make sure that the return |
247 | value is not NULL before dereferencing it. |
248 | |
249 | These two functions check if a hash table entry exists, and deletes it. |
250 | |
251 | bool hv_exists(HV*, char* key, U32 klen); |
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252 | SV* hv_delete(HV*, char* key, U32 klen, I32 flags); |
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253 | |
254 | And more miscellaneous functions: |
255 | |
256 | void hv_clear(HV*); |
257 | /* Clears all entries in hash table */ |
258 | void hv_undef(HV*); |
259 | /* Undefines the hash table */ |
260 | |
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261 | Perl keeps the actual data in linked list of structures with a typedef of HE. |
262 | These contain the actual key and value pointers (plus extra administrative |
263 | overhead). The key is a string pointer; the value is an C<SV*>. However, |
264 | once you have an C<HE*>, to get the actual key and value, use the routines |
265 | specified below. |
266 | |
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267 | I32 hv_iterinit(HV*); |
268 | /* Prepares starting point to traverse hash table */ |
269 | HE* hv_iternext(HV*); |
270 | /* Get the next entry, and return a pointer to a |
271 | structure that has both the key and value */ |
272 | char* hv_iterkey(HE* entry, I32* retlen); |
273 | /* Get the key from an HE structure and also return |
274 | the length of the key string */ |
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275 | SV* hv_iterval(HV*, HE* entry); |
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276 | /* Return a SV pointer to the value of the HE |
277 | structure */ |
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278 | SV* hv_iternextsv(HV*, char** key, I32* retlen); |
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279 | /* This convenience routine combines hv_iternext, |
280 | hv_iterkey, and hv_iterval. The key and retlen |
281 | arguments are return values for the key and its |
282 | length. The value is returned in the SV* argument */ |
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283 | |
284 | If you know the name of a hash variable, you can get a pointer to its HV |
285 | by using the following: |
286 | |
287 | HV* perl_get_hv("varname", FALSE); |
288 | |
289 | This returns NULL if the variable does not exist. |
290 | |
291 | The hash algorithm, for those who are interested, is: |
292 | |
293 | i = klen; |
294 | hash = 0; |
295 | s = key; |
296 | while (i--) |
297 | hash = hash * 33 + *s++; |
298 | |
299 | =head2 References |
300 | |
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301 | References are a special type of scalar that point to other data types |
302 | (including references). |
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303 | |
304 | To create a reference, use the following command: |
305 | |
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306 | SV* newRV((SV*) thing); |
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307 | |
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308 | The C<thing> argument can be any of an C<SV*>, C<AV*>, or C<HV*>. Once |
309 | you have a reference, you can use the following macro to dereference the |
310 | reference: |
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311 | |
312 | SvRV(SV*) |
313 | |
314 | then call the appropriate routines, casting the returned C<SV*> to either an |
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315 | C<AV*> or C<HV*>, if required. |
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316 | |
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317 | To determine if an SV is a reference, you can use the following macro: |
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318 | |
319 | SvROK(SV*) |
320 | |
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321 | To actually discover what the reference refers to, you must use the following |
322 | macro and then check the value returned. |
323 | |
324 | SvTYPE(SvRV(SV*)) |
325 | |
326 | The most useful types that will be returned are: |
327 | |
328 | SVt_IV Scalar |
329 | SVt_NV Scalar |
330 | SVt_PV Scalar |
331 | SVt_PVAV Array |
332 | SVt_PVHV Hash |
333 | SVt_PVCV Code |
334 | SVt_PVMG Blessed Scalar |
335 | |
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336 | =head2 Blessed References and Class Objects |
337 | |
338 | References are also used to support object-oriented programming. In the |
339 | OO lexicon, an object is simply a reference that has been blessed into a |
340 | package (or class). Once blessed, the programmer may now use the reference |
341 | to access the various methods in the class. |
342 | |
343 | A reference can be blessed into a package with the following function: |
344 | |
345 | SV* sv_bless(SV* sv, HV* stash); |
346 | |
347 | The C<sv> argument must be a reference. The C<stash> argument specifies |
348 | which class the reference will belong to. See the section on L<Stashes> |
349 | for information on converting class names into stashes. |
350 | |
351 | /* Still under construction */ |
352 | |
353 | Upgrades rv to reference if not already one. Creates new SV for rv to |
354 | point to. |
355 | If classname is non-null, the SV is blessed into the specified class. |
356 | SV is returned. |
357 | |
358 | SV* newSVrv(SV* rv, char* classname); |
359 | |
360 | Copies integer or double into an SV whose reference is rv. SV is blessed |
361 | if classname is non-null. |
362 | |
363 | SV* sv_setref_iv(SV* rv, char* classname, IV iv); |
364 | SV* sv_setref_nv(SV* rv, char* classname, NV iv); |
365 | |
366 | Copies pointer (I<not a string!>) into an SV whose reference is rv. |
367 | SV is blessed if classname is non-null. |
368 | |
369 | SV* sv_setref_pv(SV* rv, char* classname, PV iv); |
370 | |
371 | Copies string into an SV whose reference is rv. |
372 | Set length to 0 to let Perl calculate the string length. |
373 | SV is blessed if classname is non-null. |
374 | |
375 | SV* sv_setref_pvn(SV* rv, char* classname, PV iv, int length); |
376 | |
377 | int sv_isa(SV* sv, char* name); |
378 | int sv_isobject(SV* sv); |
379 | |
380 | =head1 Creating New Variables |
381 | |
382 | To create a new Perl variable, which can be accessed from your Perl script, |
383 | use the following routines, depending on the variable type. |
384 | |
385 | SV* perl_get_sv("varname", TRUE); |
386 | AV* perl_get_av("varname", TRUE); |
387 | HV* perl_get_hv("varname", TRUE); |
388 | |
389 | Notice the use of TRUE as the second parameter. The new variable can now |
390 | be set, using the routines appropriate to the data type. |
391 | |
392 | There are additional bits that may be OR'ed with the TRUE argument to enable |
393 | certain extra features. Those bits are: |
394 | |
395 | 0x02 Marks the variable as multiply defined, thus preventing the |
396 | "Indentifier <varname> used only once: possible typo" warning. |
397 | 0x04 Issues a "Had to create <varname> unexpectedly" warning if |
398 | the variable didn't actually exist. This is useful if |
399 | you expected the variable to already exist and want to propagate |
400 | this warning back to the user. |
401 | |
402 | If the C<varname> argument does not contain a package specifier, it is |
403 | created in the current package. |
404 | |
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405 | =head1 XSUB's and the Argument Stack |
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406 | |
407 | The XSUB mechanism is a simple way for Perl programs to access C subroutines. |
408 | An XSUB routine will have a stack that contains the arguments from the Perl |
409 | program, and a way to map from the Perl data structures to a C equivalent. |
410 | |
411 | The stack arguments are accessible through the C<ST(n)> macro, which returns |
412 | the C<n>'th stack argument. Argument 0 is the first argument passed in the |
413 | Perl subroutine call. These arguments are C<SV*>, and can be used anywhere |
414 | an C<SV*> is used. |
415 | |
416 | Most of the time, output from the C routine can be handled through use of |
417 | the RETVAL and OUTPUT directives. However, there are some cases where the |
418 | argument stack is not already long enough to handle all the return values. |
419 | An example is the POSIX tzname() call, which takes no arguments, but returns |
420 | two, the local timezone's standard and summer time abbreviations. |
421 | |
422 | To handle this situation, the PPCODE directive is used and the stack is |
423 | extended using the macro: |
424 | |
425 | EXTEND(sp, num); |
426 | |
427 | where C<sp> is the stack pointer, and C<num> is the number of elements the |
428 | stack should be extended by. |
429 | |
430 | Now that there is room on the stack, values can be pushed on it using the |
431 | macros to push IV's, doubles, strings, and SV pointers respectively: |
432 | |
433 | PUSHi(IV) |
434 | PUSHn(double) |
435 | PUSHp(char*, I32) |
436 | PUSHs(SV*) |
437 | |
438 | And now the Perl program calling C<tzname>, the two values will be assigned |
439 | as in: |
440 | |
441 | ($standard_abbrev, $summer_abbrev) = POSIX::tzname; |
442 | |
443 | An alternate (and possibly simpler) method to pushing values on the stack is |
444 | to use the macros: |
445 | |
446 | XPUSHi(IV) |
447 | XPUSHn(double) |
448 | XPUSHp(char*, I32) |
449 | XPUSHs(SV*) |
450 | |
451 | These macros automatically adjust the stack for you, if needed. |
452 | |
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453 | For more information, consult L<perlxs>. |
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454 | |
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455 | =head1 Mortality |
456 | |
457 | In Perl, values are normally "immortal" -- that is, they are not freed unless |
458 | explicitly done so (via the Perl C<undef> call or other routines in Perl |
459 | itself). |
460 | |
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461 | Add cruft about reference counts. |
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462 | int SvREFCNT(SV* sv); |
463 | void SvREFCNT_inc(SV* sv); |
464 | void SvREFCNT_dec(SV* sv); |
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465 | |
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466 | In the above example with C<tzname>, we needed to create two new SV's to push |
467 | onto the argument stack, that being the two strings. However, we don't want |
468 | these new SV's to stick around forever because they will eventually be |
469 | copied into the SV's that hold the two scalar variables. |
470 | |
471 | An SV (or AV or HV) that is "mortal" acts in all ways as a normal "immortal" |
472 | SV, AV, or HV, but is only valid in the "current context". When the Perl |
473 | interpreter leaves the current context, the mortal SV, AV, or HV is |
474 | automatically freed. Generally the "current context" means a single |
475 | Perl statement. |
476 | |
477 | To create a mortal variable, use the functions: |
478 | |
479 | SV* sv_newmortal() |
480 | SV* sv_2mortal(SV*) |
481 | SV* sv_mortalcopy(SV*) |
482 | |
483 | The first call creates a mortal SV, the second converts an existing SV to |
484 | a mortal SV, the third creates a mortal copy of an existing SV. |
485 | |
486 | The mortal routines are not just for SV's -- AV's and HV's can be made mortal |
487 | by passing their address (and casting them to C<SV*>) to the C<sv_2mortal> or |
488 | C<sv_mortalcopy> routines. |
489 | |
cb1a09d0 |
490 | >From Ilya: |
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491 | Beware that the sv_2mortal() call is eventually equivalent to |
492 | svREFCNT_dec(). A value can happily be mortal in two different contexts, |
493 | and it will be svREFCNT_dec()ed twice, once on exit from these |
494 | contexts. It can also be mortal twice in the same context. This means |
495 | that you should be very careful to make a value mortal exactly as many |
496 | times as it is needed. The value that go to the Perl stack I<should> |
497 | be mortal. |
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498 | |
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499 | You should be careful about creating mortal variables. It is possible for |
500 | strange things to happen should you make the same value mortal within |
501 | multiple contexts. |
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502 | |
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503 | =head1 Stashes |
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504 | |
505 | A stash is a hash table (associative array) that contains all of the |
506 | different objects that are contained within a package. Each key of the |
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507 | stash is a symbol name (shared by all the different types of objects |
508 | that have the same name), and each value in the hash table is called a |
509 | GV (for Glob Value). This GV in turn contains references to the various |
510 | objects of that name, including (but not limited to) the following: |
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511 | |
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512 | Scalar Value |
513 | Array Value |
514 | Hash Value |
515 | File Handle |
516 | Directory Handle |
517 | Format |
518 | Subroutine |
519 | |
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520 | Perl stores various stashes in a separate GV structure (for global |
521 | variable) but represents them with an HV structure. The keys in this |
522 | larger GV are the various package names; the values are the C<GV*>'s |
523 | which are stashes. It may help to think of a stash purely as an HV, |
524 | and that the term "GV" means the global variable hash. |
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525 | |
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526 | To get the stash pointer for a particular package, use the function: |
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527 | |
528 | HV* gv_stashpv(char* name, I32 create) |
529 | HV* gv_stashsv(SV*, I32 create) |
530 | |
531 | The first function takes a literal string, the second uses the string stored |
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532 | in the SV. Remember that a stash is just a hash table, so you get back an |
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533 | C<HV*>. The C<create> flag will create a new package if it is set. |
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534 | |
535 | The name that C<gv_stash*v> wants is the name of the package whose symbol table |
536 | you want. The default package is called C<main>. If you have multiply nested |
d1b91892 |
537 | packages, pass their names to C<gv_stash*v>, separated by C<::> as in the Perl |
538 | language itself. |
a0d0e21e |
539 | |
540 | Alternately, if you have an SV that is a blessed reference, you can find |
541 | out the stash pointer by using: |
542 | |
543 | HV* SvSTASH(SvRV(SV*)); |
544 | |
545 | then use the following to get the package name itself: |
546 | |
547 | char* HvNAME(HV* stash); |
548 | |
549 | If you need to return a blessed value to your Perl script, you can use the |
550 | following function: |
551 | |
552 | SV* sv_bless(SV*, HV* stash) |
553 | |
554 | where the first argument, an C<SV*>, must be a reference, and the second |
555 | argument is a stash. The returned C<SV*> can now be used in the same way |
556 | as any other SV. |
557 | |
d1b91892 |
558 | For more information on references and blessings, consult L<perlref>. |
559 | |
a0d0e21e |
560 | =head1 Magic |
561 | |
d1b91892 |
562 | [This section still under construction. Ignore everything here. Post no |
563 | bills. Everything not permitted is forbidden.] |
564 | |
565 | # Version 6, 1995/1/27 |
566 | |
567 | Any SV may be magical, that is, it has special features that a normal |
568 | SV does not have. These features are stored in the SV structure in a |
569 | linked list of C<struct magic>'s, typedef'ed to C<MAGIC>. |
570 | |
571 | struct magic { |
572 | MAGIC* mg_moremagic; |
573 | MGVTBL* mg_virtual; |
574 | U16 mg_private; |
575 | char mg_type; |
576 | U8 mg_flags; |
577 | SV* mg_obj; |
578 | char* mg_ptr; |
579 | I32 mg_len; |
580 | }; |
581 | |
582 | Note this is current as of patchlevel 0, and could change at any time. |
583 | |
584 | =head2 Assigning Magic |
585 | |
586 | Perl adds magic to an SV using the sv_magic function: |
587 | |
588 | void sv_magic(SV* sv, SV* obj, int how, char* name, I32 namlen); |
589 | |
590 | The C<sv> argument is a pointer to the SV that is to acquire a new magical |
591 | feature. |
592 | |
593 | If C<sv> is not already magical, Perl uses the C<SvUPGRADE> macro to |
594 | set the C<SVt_PVMG> flag for the C<sv>. Perl then continues by adding |
595 | it to the beginning of the linked list of magical features. Any prior |
596 | entry of the same type of magic is deleted. Note that this can be |
597 | overriden, and multiple instances of the same type of magic can be |
598 | associated with an SV. |
599 | |
600 | The C<name> and C<namlem> arguments are used to associate a string with |
601 | the magic, typically the name of a variable. C<namlem> is stored in the |
602 | C<mg_len> field and if C<name> is non-null and C<namlem> >= 0 a malloc'd |
603 | copy of the name is stored in C<mg_ptr> field. |
604 | |
605 | The sv_magic function uses C<how> to determine which, if any, predefined |
606 | "Magic Virtual Table" should be assigned to the C<mg_virtual> field. |
cb1a09d0 |
607 | See the "Magic Virtual Table" section below. The C<how> argument is also |
608 | stored in the C<mg_type> field. |
d1b91892 |
609 | |
610 | The C<obj> argument is stored in the C<mg_obj> field of the C<MAGIC> |
611 | structure. If it is not the same as the C<sv> argument, the reference |
612 | count of the C<obj> object is incremented. If it is the same, or if |
613 | the C<how> argument is "#", or if it is a null pointer, then C<obj> is |
614 | merely stored, without the reference count being incremented. |
615 | |
cb1a09d0 |
616 | There is also a function to add magic to an C<HV>: |
617 | |
618 | void hv_magic(HV *hv, GV *gv, int how); |
619 | |
620 | This simply calls C<sv_magic> and coerces the C<gv> argument into an C<SV>. |
621 | |
622 | To remove the magic from an SV, call the function sv_unmagic: |
623 | |
624 | void sv_unmagic(SV *sv, int type); |
625 | |
626 | The C<type> argument should be equal to the C<how> value when the C<SV> |
627 | was initially made magical. |
628 | |
d1b91892 |
629 | =head2 Magic Virtual Tables |
630 | |
631 | The C<mg_virtual> field in the C<MAGIC> structure is a pointer to a |
632 | C<MGVTBL>, which is a structure of function pointers and stands for |
633 | "Magic Virtual Table" to handle the various operations that might be |
634 | applied to that variable. |
635 | |
636 | The C<MGVTBL> has five pointers to the following routine types: |
637 | |
638 | int (*svt_get)(SV* sv, MAGIC* mg); |
639 | int (*svt_set)(SV* sv, MAGIC* mg); |
640 | U32 (*svt_len)(SV* sv, MAGIC* mg); |
641 | int (*svt_clear)(SV* sv, MAGIC* mg); |
642 | int (*svt_free)(SV* sv, MAGIC* mg); |
643 | |
644 | This MGVTBL structure is set at compile-time in C<perl.h> and there are |
645 | currently 19 types (or 21 with overloading turned on). These different |
646 | structures contain pointers to various routines that perform additional |
647 | actions depending on which function is being called. |
648 | |
649 | Function pointer Action taken |
650 | ---------------- ------------ |
651 | svt_get Do something after the value of the SV is retrieved. |
652 | svt_set Do something after the SV is assigned a value. |
653 | svt_len Report on the SV's length. |
654 | svt_clear Clear something the SV represents. |
655 | svt_free Free any extra storage associated with the SV. |
656 | |
657 | For instance, the MGVTBL structure called C<vtbl_sv> (which corresponds |
658 | to an C<mg_type> of '\0') contains: |
659 | |
660 | { magic_get, magic_set, magic_len, 0, 0 } |
661 | |
662 | Thus, when an SV is determined to be magical and of type '\0', if a get |
663 | operation is being performed, the routine C<magic_get> is called. All |
664 | the various routines for the various magical types begin with C<magic_>. |
665 | |
666 | The current kinds of Magic Virtual Tables are: |
667 | |
668 | mg_type MGVTBL Type of magicalness |
669 | ------- ------ ------------------- |
670 | \0 vtbl_sv Regexp??? |
671 | A vtbl_amagic Operator Overloading |
672 | a vtbl_amagicelem Operator Overloading |
673 | c 0 Used in Operator Overloading |
674 | B vtbl_bm Boyer-Moore??? |
675 | E vtbl_env %ENV hash |
676 | e vtbl_envelem %ENV hash element |
677 | g vtbl_mglob Regexp /g flag??? |
678 | I vtbl_isa @ISA array |
679 | i vtbl_isaelem @ISA array element |
680 | L 0 (but sets RMAGICAL) Perl Module/Debugger??? |
681 | l vtbl_dbline Debugger? |
682 | P vtbl_pack Tied Array or Hash |
683 | p vtbl_packelem Tied Array or Hash element |
684 | q vtbl_packelem Tied Scalar or Handle |
685 | S vtbl_sig Signal Hash |
686 | s vtbl_sigelem Signal Hash element |
687 | t vtbl_taint Taintedness |
688 | U vtbl_uvar ??? |
689 | v vtbl_vec Vector |
690 | x vtbl_substr Substring??? |
691 | * vtbl_glob GV??? |
692 | # vtbl_arylen Array Length |
693 | . vtbl_pos $. scalar variable |
694 | ~ Reserved for extensions, but multiple extensions may clash |
695 | |
696 | When an upper-case and lower-case letter both exist in the table, then the |
697 | upper-case letter is used to represent some kind of composite type (a list |
698 | or a hash), and the lower-case letter is used to represent an element of |
699 | that composite type. |
700 | |
701 | =head2 Finding Magic |
702 | |
703 | MAGIC* mg_find(SV*, int type); /* Finds the magic pointer of that type */ |
704 | |
705 | This routine returns a pointer to the C<MAGIC> structure stored in the SV. |
706 | If the SV does not have that magical feature, C<NULL> is returned. Also, |
707 | if the SV is not of type SVt_PVMG, Perl may core-dump. |
708 | |
709 | int mg_copy(SV* sv, SV* nsv, char* key, STRLEN klen); |
710 | |
711 | This routine checks to see what types of magic C<sv> has. If the mg_type |
712 | field is an upper-case letter, then the mg_obj is copied to C<nsv>, but |
713 | the mg_type field is changed to be the lower-case letter. |
a0d0e21e |
714 | |
715 | =head1 Double-Typed SV's |
716 | |
717 | Scalar variables normally contain only one type of value, an integer, |
718 | double, pointer, or reference. Perl will automatically convert the |
719 | actual scalar data from the stored type into the requested type. |
720 | |
721 | Some scalar variables contain more than one type of scalar data. For |
722 | example, the variable C<$!> contains either the numeric value of C<errno> |
d1b91892 |
723 | or its string equivalent from either C<strerror> or C<sys_errlist[]>. |
a0d0e21e |
724 | |
725 | To force multiple data values into an SV, you must do two things: use the |
726 | C<sv_set*v> routines to add the additional scalar type, then set a flag |
727 | so that Perl will believe it contains more than one type of data. The |
728 | four macros to set the flags are: |
729 | |
730 | SvIOK_on |
731 | SvNOK_on |
732 | SvPOK_on |
733 | SvROK_on |
734 | |
735 | The particular macro you must use depends on which C<sv_set*v> routine |
736 | you called first. This is because every C<sv_set*v> routine turns on |
737 | only the bit for the particular type of data being set, and turns off |
738 | all the rest. |
739 | |
740 | For example, to create a new Perl variable called "dberror" that contains |
741 | both the numeric and descriptive string error values, you could use the |
742 | following code: |
743 | |
744 | extern int dberror; |
745 | extern char *dberror_list; |
746 | |
747 | SV* sv = perl_get_sv("dberror", TRUE); |
748 | sv_setiv(sv, (IV) dberror); |
749 | sv_setpv(sv, dberror_list[dberror]); |
750 | SvIOK_on(sv); |
751 | |
752 | If the order of C<sv_setiv> and C<sv_setpv> had been reversed, then the |
753 | macro C<SvPOK_on> would need to be called instead of C<SvIOK_on>. |
754 | |
755 | =head1 Calling Perl Routines from within C Programs |
756 | |
757 | There are four routines that can be used to call a Perl subroutine from |
758 | within a C program. These four are: |
759 | |
760 | I32 perl_call_sv(SV*, I32); |
761 | I32 perl_call_pv(char*, I32); |
762 | I32 perl_call_method(char*, I32); |
763 | I32 perl_call_argv(char*, I32, register char**); |
764 | |
d1b91892 |
765 | The routine most often used is C<perl_call_sv>. The C<SV*> argument |
766 | contains either the name of the Perl subroutine to be called, or a |
767 | reference to the subroutine. The second argument consists of flags |
768 | that control the context in which the subroutine is called, whether |
769 | or not the subroutine is being passed arguments, how errors should be |
770 | trapped, and how to treat return values. |
a0d0e21e |
771 | |
772 | All four routines return the number of arguments that the subroutine returned |
773 | on the Perl stack. |
774 | |
d1b91892 |
775 | When using any of these routines (except C<perl_call_argv>), the programmer |
776 | must manipulate the Perl stack. These include the following macros and |
777 | functions: |
a0d0e21e |
778 | |
779 | dSP |
780 | PUSHMARK() |
781 | PUTBACK |
782 | SPAGAIN |
783 | ENTER |
784 | SAVETMPS |
785 | FREETMPS |
786 | LEAVE |
787 | XPUSH*() |
cb1a09d0 |
788 | POP*() |
a0d0e21e |
789 | |
790 | For more information, consult L<perlcall>. |
791 | |
792 | =head1 Memory Allocation |
793 | |
d1b91892 |
794 | It is strongly suggested that you use the version of malloc that is distributed |
795 | with Perl. It keeps pools of various sizes of unallocated memory in order to |
796 | more quickly satisfy allocation requests. |
797 | However, on some platforms, it may cause spurious malloc or free errors. |
798 | |
799 | New(x, pointer, number, type); |
800 | Newc(x, pointer, number, type, cast); |
801 | Newz(x, pointer, number, type); |
802 | |
803 | These three macros are used to initially allocate memory. The first argument |
804 | C<x> was a "magic cookie" that was used to keep track of who called the macro, |
805 | to help when debugging memory problems. However, the current code makes no |
806 | use of this feature (Larry has switched to using a run-time memory checker), |
807 | so this argument can be any number. |
808 | |
809 | The second argument C<pointer> will point to the newly allocated memory. |
810 | The third and fourth arguments C<number> and C<type> specify how many of |
811 | the specified type of data structure should be allocated. The argument |
812 | C<type> is passed to C<sizeof>. The final argument to C<Newc>, C<cast>, |
813 | should be used if the C<pointer> argument is different from the C<type> |
814 | argument. |
815 | |
816 | Unlike the C<New> and C<Newc> macros, the C<Newz> macro calls C<memzero> |
817 | to zero out all the newly allocated memory. |
818 | |
819 | Renew(pointer, number, type); |
820 | Renewc(pointer, number, type, cast); |
821 | Safefree(pointer) |
822 | |
823 | These three macros are used to change a memory buffer size or to free a |
824 | piece of memory no longer needed. The arguments to C<Renew> and C<Renewc> |
825 | match those of C<New> and C<Newc> with the exception of not needing the |
826 | "magic cookie" argument. |
827 | |
828 | Move(source, dest, number, type); |
829 | Copy(source, dest, number, type); |
830 | Zero(dest, number, type); |
831 | |
832 | These three macros are used to move, copy, or zero out previously allocated |
833 | memory. The C<source> and C<dest> arguments point to the source and |
834 | destination starting points. Perl will move, copy, or zero out C<number> |
835 | instances of the size of the C<type> data structure (using the C<sizeof> |
836 | function). |
a0d0e21e |
837 | |
cb1a09d0 |
838 | =head1 API LISTING |
a0d0e21e |
839 | |
cb1a09d0 |
840 | This is a listing of functions, macros, flags, and variables that may be |
841 | useful to extension writers or that may be found while reading other |
842 | extensions. |
a0d0e21e |
843 | |
cb1a09d0 |
844 | =over 8 |
a0d0e21e |
845 | |
cb1a09d0 |
846 | =item AvFILL |
847 | |
848 | See C<av_len>. |
849 | |
850 | =item av_clear |
851 | |
852 | Clears an array, making it empty. |
853 | |
854 | void av_clear _((AV* ar)); |
855 | |
856 | =item av_extend |
857 | |
858 | Pre-extend an array. The C<key> is the index to which the array should be |
859 | extended. |
860 | |
861 | void av_extend _((AV* ar, I32 key)); |
862 | |
863 | =item av_fetch |
864 | |
865 | Returns the SV at the specified index in the array. The C<key> is the |
866 | index. If C<lval> is set then the fetch will be part of a store. Check |
867 | that the return value is non-null before dereferencing it to a C<SV*>. |
868 | |
869 | SV** av_fetch _((AV* ar, I32 key, I32 lval)); |
870 | |
871 | =item av_len |
872 | |
873 | Returns the highest index in the array. Returns -1 if the array is empty. |
874 | |
875 | I32 av_len _((AV* ar)); |
876 | |
877 | =item av_make |
878 | |
879 | Creats a new AV and populates it with a list of SVs. The SVs are copied |
880 | into the array, so they may be freed after the call to av_make. |
881 | |
882 | AV* av_make _((I32 size, SV** svp)); |
883 | |
884 | =item av_pop |
885 | |
886 | Pops an SV off the end of the array. Returns C<&sv_undef> if the array is |
887 | empty. |
888 | |
889 | SV* av_pop _((AV* ar)); |
890 | |
891 | =item av_push |
892 | |
893 | Pushes an SV onto the end of the array. |
894 | |
895 | void av_push _((AV* ar, SV* val)); |
896 | |
897 | =item av_shift |
898 | |
899 | Shifts an SV off the beginning of the array. |
900 | |
901 | SV* av_shift _((AV* ar)); |
902 | |
903 | =item av_store |
904 | |
905 | Stores an SV in an array. The array index is specified as C<key>. The |
906 | return value will be null if the operation failed, otherwise it can be |
907 | dereferenced to get the original C<SV*>. |
908 | |
909 | SV** av_store _((AV* ar, I32 key, SV* val)); |
910 | |
911 | =item av_undef |
912 | |
913 | Undefines the array. |
914 | |
915 | void av_undef _((AV* ar)); |
916 | |
917 | =item av_unshift |
918 | |
919 | Unshift an SV onto the beginning of the array. |
920 | |
921 | void av_unshift _((AV* ar, I32 num)); |
922 | |
923 | =item CLASS |
924 | |
925 | Variable which is setup by C<xsubpp> to indicate the class name for a C++ XS |
926 | constructor. This is always a C<char*>. See C<THIS> and L<perlxs>. |
927 | |
928 | =item Copy |
929 | |
930 | The XSUB-writer's interface to the C C<memcpy> function. The C<s> is the |
931 | source, C<d> is the destination, C<n> is the number of items, and C<t> is |
932 | the type. |
933 | |
934 | (void) Copy( s, d, n, t ); |
935 | |
936 | =item croak |
937 | |
938 | This is the XSUB-writer's interface to Perl's C<die> function. Use this |
939 | function the same way you use the C C<printf> function. See C<warn>. |
940 | |
941 | =item CvSTASH |
942 | |
943 | Returns the stash of the CV. |
944 | |
945 | HV * CvSTASH( SV* sv ) |
946 | |
947 | =item DBsingle |
948 | |
949 | When Perl is run in debugging mode, with the B<-d> switch, this SV is a |
950 | boolean which indicates whether subs are being single-stepped. |
951 | Single-stepping is automatically turned on after every step. See C<DBsub>. |
952 | |
953 | =item DBsub |
954 | |
955 | When Perl is run in debugging mode, with the B<-d> switch, this GV contains |
956 | the SV which holds the name of the sub being debugged. See C<DBsingle>. |
957 | The sub name can be found by |
958 | |
959 | SvPV( GvSV( DBsub ), na ) |
960 | |
961 | =item dMARK |
962 | |
963 | Declare a stack marker for the XSUB. See C<MARK> and C<dORIGMARK>. |
964 | |
965 | =item dORIGMARK |
966 | |
967 | Saves the original stack mark for the XSUB. See C<ORIGMARK>. |
968 | |
969 | =item dSP |
970 | |
971 | Declares a stack pointer for the XSUB. See C<SP>. |
972 | |
973 | =item dXSARGS |
974 | |
975 | Sets up stack and mark pointers for an XSUB, calling dSP and dMARK. This is |
976 | usually handled automatically by C<xsubpp>. Declares the C<items> variable |
977 | to indicate the number of items on the stack. |
978 | |
979 | =item ENTER |
980 | |
981 | Opening bracket on a callback. See C<LEAVE> and L<perlcall>. |
982 | |
983 | ENTER; |
984 | |
985 | =item EXTEND |
986 | |
987 | Used to extend the argument stack for an XSUB's return values. |
988 | |
989 | EXTEND( sp, int x ); |
990 | |
991 | =item FREETMPS |
992 | |
993 | Closing bracket for temporaries on a callback. See C<SAVETMPS> and |
994 | L<perlcall>. |
995 | |
996 | FREETMPS; |
997 | |
998 | =item G_ARRAY |
999 | |
1000 | Used to indicate array context. See C<GIMME> and L<perlcall>. |
1001 | |
1002 | =item G_DISCARD |
1003 | |
1004 | Indicates that arguments returned from a callback should be discarded. See |
1005 | L<perlcall>. |
1006 | |
1007 | =item G_EVAL |
1008 | |
1009 | Used to force a Perl C<eval> wrapper around a callback. See L<perlcall>. |
1010 | |
1011 | =item GIMME |
1012 | |
1013 | The XSUB-writer's equivalent to Perl's C<wantarray>. Returns C<G_SCALAR> or |
1014 | C<G_ARRAY> for scalar or array context. |
1015 | |
1016 | =item G_NOARGS |
1017 | |
1018 | Indicates that no arguments are being sent to a callback. See L<perlcall>. |
1019 | |
1020 | =item G_SCALAR |
1021 | |
1022 | Used to indicate scalar context. See C<GIMME> and L<perlcall>. |
1023 | |
1024 | =item gv_stashpv |
1025 | |
1026 | Returns a pointer to the stash for a specified package. If C<create> is set |
1027 | then the package will be created if it does not already exist. If C<create> |
1028 | is not set and the package does not exist then NULL is returned. |
1029 | |
1030 | HV* gv_stashpv _((char* name, I32 create)); |
1031 | |
1032 | =item gv_stashsv |
1033 | |
1034 | Returns a pointer to the stash for a specified package. See C<gv_stashpv>. |
1035 | |
1036 | HV* gv_stashsv _((SV* sv, I32 create)); |
1037 | |
1038 | =item GvSV |
1039 | |
1040 | Return the SV from the GV. |
1041 | |
1042 | =item he_free |
1043 | |
1044 | Releases a hash entry from an iterator. See C<hv_iternext>. |
1045 | |
1046 | =item hv_clear |
1047 | |
1048 | Clears a hash, making it empty. |
1049 | |
1050 | void hv_clear _((HV* tb)); |
1051 | |
1052 | =item hv_delete |
1053 | |
1054 | Deletes a key/value pair in the hash. The value SV is removed from the hash |
1055 | and returned to the caller. The C<lken> is the length of the key. The |
1056 | C<flags> value will normally be zero; if set to G_DISCARD then null will be |
1057 | returned. |
1058 | |
1059 | SV* hv_delete _((HV* tb, char* key, U32 klen, I32 flags)); |
1060 | |
1061 | =item hv_exists |
1062 | |
1063 | Returns a boolean indicating whether the specified hash key exists. The |
1064 | C<lken> is the length of the key. |
1065 | |
1066 | bool hv_exists _((HV* tb, char* key, U32 klen)); |
1067 | |
1068 | =item hv_fetch |
1069 | |
1070 | Returns the SV which corresponds to the specified key in the hash. The |
1071 | C<lken> is the length of the key. If C<lval> is set then the fetch will be |
1072 | part of a store. Check that the return value is non-null before |
1073 | dereferencing it to a C<SV*>. |
1074 | |
1075 | SV** hv_fetch _((HV* tb, char* key, U32 klen, I32 lval)); |
1076 | |
1077 | =item hv_iterinit |
1078 | |
1079 | Prepares a starting point to traverse a hash table. |
1080 | |
1081 | I32 hv_iterinit _((HV* tb)); |
1082 | |
1083 | =item hv_iterkey |
1084 | |
1085 | Returns the key from the current position of the hash iterator. See |
1086 | C<hv_iterinit>. |
1087 | |
1088 | char* hv_iterkey _((HE* entry, I32* retlen)); |
1089 | |
1090 | =item hv_iternext |
1091 | |
1092 | Returns entries from a hash iterator. See C<hv_iterinit>. |
1093 | |
1094 | HE* hv_iternext _((HV* tb)); |
1095 | |
1096 | =item hv_iternextsv |
1097 | |
1098 | Performs an C<hv_iternext>, C<hv_iterkey>, and C<hv_iterval> in one |
1099 | operation. |
1100 | |
1101 | SV * hv_iternextsv _((HV* hv, char** key, I32* retlen)); |
1102 | |
1103 | =item hv_iterval |
1104 | |
1105 | Returns the value from the current position of the hash iterator. See |
1106 | C<hv_iterkey>. |
1107 | |
1108 | SV* hv_iterval _((HV* tb, HE* entry)); |
1109 | |
1110 | =item hv_magic |
1111 | |
1112 | Adds magic to a hash. See C<sv_magic>. |
1113 | |
1114 | void hv_magic _((HV* hv, GV* gv, int how)); |
1115 | |
1116 | =item HvNAME |
1117 | |
1118 | Returns the package name of a stash. See C<SvSTASH>, C<CvSTASH>. |
1119 | |
1120 | char *HvNAME (HV* stash) |
1121 | |
1122 | =item hv_store |
1123 | |
1124 | Stores an SV in a hash. The hash key is specified as C<key> and C<klen> is |
1125 | the length of the key. The C<hash> parameter is the pre-computed hash |
1126 | value; if it is zero then Perl will compute it. The return value will be |
1127 | null if the operation failed, otherwise it can be dereferenced to get the |
1128 | original C<SV*>. |
1129 | |
1130 | SV** hv_store _((HV* tb, char* key, U32 klen, SV* val, U32 hash)); |
1131 | |
1132 | =item hv_undef |
1133 | |
1134 | Undefines the hash. |
1135 | |
1136 | void hv_undef _((HV* tb)); |
1137 | |
1138 | =item isALNUM |
1139 | |
1140 | Returns a boolean indicating whether the C C<char> is an ascii alphanumeric |
1141 | character or digit. |
1142 | |
1143 | int isALNUM (char c) |
1144 | |
1145 | =item isALPHA |
1146 | |
1147 | Returns a boolean indicating whether the C C<char> is an ascii alphanumeric |
1148 | character. |
1149 | |
1150 | int isALPHA (char c) |
1151 | |
1152 | =item isDIGIT |
1153 | |
1154 | Returns a boolean indicating whether the C C<char> is an ascii digit. |
1155 | |
1156 | int isDIGIT (char c) |
1157 | |
1158 | =item isLOWER |
1159 | |
1160 | Returns a boolean indicating whether the C C<char> is a lowercase character. |
1161 | |
1162 | int isLOWER (char c) |
1163 | |
1164 | =item isSPACE |
1165 | |
1166 | Returns a boolean indicating whether the C C<char> is whitespace. |
1167 | |
1168 | int isSPACE (char c) |
1169 | |
1170 | =item isUPPER |
1171 | |
1172 | Returns a boolean indicating whether the C C<char> is an uppercase character. |
1173 | |
1174 | int isUPPER (char c) |
1175 | |
1176 | =item items |
1177 | |
1178 | Variable which is setup by C<xsubpp> to indicate the number of items on the |
1179 | stack. See L<perlxs>. |
1180 | |
1181 | =item LEAVE |
1182 | |
1183 | Closing bracket on a callback. See C<ENTER> and L<perlcall>. |
1184 | |
1185 | LEAVE; |
1186 | |
1187 | =item MARK |
1188 | |
1189 | Stack marker for the XSUB. See C<dMARK>. |
1190 | |
1191 | =item mg_clear |
1192 | |
1193 | Clear something magical that the SV represents. See C<sv_magic>. |
1194 | |
1195 | int mg_clear _((SV* sv)); |
1196 | |
1197 | =item mg_copy |
1198 | |
1199 | Copies the magic from one SV to another. See C<sv_magic>. |
1200 | |
1201 | int mg_copy _((SV *, SV *, char *, STRLEN)); |
1202 | |
1203 | =item mg_find |
1204 | |
1205 | Finds the magic pointer for type matching the SV. See C<sv_magic>. |
1206 | |
1207 | MAGIC* mg_find _((SV* sv, int type)); |
1208 | |
1209 | =item mg_free |
1210 | |
1211 | Free any magic storage used by the SV. See C<sv_magic>. |
1212 | |
1213 | int mg_free _((SV* sv)); |
1214 | |
1215 | =item mg_get |
1216 | |
1217 | Do magic after a value is retrieved from the SV. See C<sv_magic>. |
1218 | |
1219 | int mg_get _((SV* sv)); |
1220 | |
1221 | =item mg_len |
1222 | |
1223 | Report on the SV's length. See C<sv_magic>. |
1224 | |
1225 | U32 mg_len _((SV* sv)); |
1226 | |
1227 | =item mg_magical |
1228 | |
1229 | Turns on the magical status of an SV. See C<sv_magic>. |
1230 | |
1231 | void mg_magical _((SV* sv)); |
1232 | |
1233 | =item mg_set |
1234 | |
1235 | Do magic after a value is assigned to the SV. See C<sv_magic>. |
1236 | |
1237 | int mg_set _((SV* sv)); |
1238 | |
1239 | =item Move |
1240 | |
1241 | The XSUB-writer's interface to the C C<memmove> function. The C<s> is the |
1242 | source, C<d> is the destination, C<n> is the number of items, and C<t> is |
1243 | the type. |
1244 | |
1245 | (void) Move( s, d, n, t ); |
1246 | |
1247 | =item na |
1248 | |
1249 | A variable which may be used with C<SvPV> to tell Perl to calculate the |
1250 | string length. |
1251 | |
1252 | =item New |
1253 | |
1254 | The XSUB-writer's interface to the C C<malloc> function. |
1255 | |
1256 | void * New( x, void *ptr, int size, type ) |
1257 | |
1258 | =item Newc |
1259 | |
1260 | The XSUB-writer's interface to the C C<malloc> function, with cast. |
1261 | |
1262 | void * Newc( x, void *ptr, int size, type, cast ) |
1263 | |
1264 | =item Newz |
1265 | |
1266 | The XSUB-writer's interface to the C C<malloc> function. The allocated |
1267 | memory is zeroed with C<memzero>. |
1268 | |
1269 | void * Newz( x, void *ptr, int size, type ) |
1270 | |
1271 | =item newAV |
1272 | |
1273 | Creates a new AV. The refcount is set to 1. |
1274 | |
1275 | AV* newAV _((void)); |
1276 | |
1277 | =item newHV |
1278 | |
1279 | Creates a new HV. The refcount is set to 1. |
1280 | |
1281 | HV* newHV _((void)); |
1282 | |
1283 | =item newRV |
1284 | |
1285 | Creates an RV wrapper for an SV. The refcount for the original SV is |
1286 | incremented. |
1287 | |
1288 | SV* newRV _((SV* ref)); |
1289 | |
1290 | =item newSV |
1291 | |
1292 | Creates a new SV. The C<len> parameter indicates the number of bytes of |
1293 | pre-allocated string space the SV should have. The refcount for the new SV |
1294 | is set to 1. |
1295 | |
1296 | SV* newSV _((STRLEN len)); |
1297 | |
1298 | =item newSViv |
1299 | |
1300 | Creates a new SV and copies an integer into it. The refcount for the SV is |
1301 | set to 1. |
1302 | |
1303 | SV* newSViv _((IV i)); |
1304 | |
1305 | =item newSVnv |
1306 | |
1307 | Creates a new SV and copies a double into it. The refcount for the SV is |
1308 | set to 1. |
1309 | |
1310 | SV* newSVnv _((NV i)); |
1311 | |
1312 | =item newSVpv |
1313 | |
1314 | Creates a new SV and copies a string into it. The refcount for the SV is |
1315 | set to 1. If C<len> is zero then Perl will compute the length. |
1316 | |
1317 | SV* newSVpv _((char* s, STRLEN len)); |
1318 | |
1319 | =item newSVrv |
1320 | |
1321 | Creates a new SV for the RV, C<rv>, to point to. If C<rv> is not an RV then |
1322 | it will be upgraded one. If C<classname> is non-null then the new SV will |
1323 | be blessed in the specified package. The new SV is returned and its |
1324 | refcount is 1. |
1325 | |
1326 | SV* newSVrv _((SV* rv, char* classname)); |
1327 | |
1328 | =item newSVsv |
1329 | |
1330 | Creates a new SV which is an exact duplicate of the orignal SV. |
1331 | |
1332 | SV* newSVsv _((SV* old)); |
1333 | |
1334 | =item newXS |
1335 | |
1336 | Used by C<xsubpp> to hook up XSUBs as Perl subs. |
1337 | |
1338 | =item newXSproto |
1339 | |
1340 | Used by C<xsubpp> to hook up XSUBs as Perl subs. Adds Perl prototypes to |
1341 | the subs. |
1342 | |
1343 | =item Nullav |
1344 | |
1345 | Null AV pointer. |
1346 | |
1347 | =item Nullch |
1348 | |
1349 | Null character pointer. |
1350 | |
1351 | =item Nullcv |
1352 | |
1353 | Null CV pointer. |
1354 | |
1355 | =item Nullhv |
1356 | |
1357 | Null HV pointer. |
1358 | |
1359 | =item Nullsv |
1360 | |
1361 | Null SV pointer. |
1362 | |
1363 | =item ORIGMARK |
1364 | |
1365 | The original stack mark for the XSUB. See C<dORIGMARK>. |
1366 | |
1367 | =item perl_alloc |
1368 | |
1369 | Allocates a new Perl interpreter. See L<perlembed>. |
1370 | |
1371 | =item perl_call_argv |
1372 | |
1373 | Performs a callback to the specified Perl sub. See L<perlcall>. |
1374 | |
1375 | I32 perl_call_argv _((char* subname, I32 flags, char** argv)); |
1376 | |
1377 | =item perl_call_method |
1378 | |
1379 | Performs a callback to the specified Perl method. The blessed object must |
1380 | be on the stack. See L<perlcall>. |
1381 | |
1382 | I32 perl_call_method _((char* methname, I32 flags)); |
1383 | |
1384 | =item perl_call_pv |
1385 | |
1386 | Performs a callback to the specified Perl sub. See L<perlcall>. |
1387 | |
1388 | I32 perl_call_pv _((char* subname, I32 flags)); |
1389 | |
1390 | =item perl_call_sv |
1391 | |
1392 | Performs a callback to the Perl sub whose name is in the SV. See |
1393 | L<perlcall>. |
1394 | |
1395 | I32 perl_call_sv _((SV* sv, I32 flags)); |
1396 | |
1397 | =item perl_construct |
1398 | |
1399 | Initializes a new Perl interpreter. See L<perlembed>. |
1400 | |
1401 | =item perl_destruct |
1402 | |
1403 | Shuts down a Perl interpreter. See L<perlembed>. |
1404 | |
1405 | =item perl_eval_sv |
1406 | |
1407 | Tells Perl to C<eval> the string in the SV. |
1408 | |
1409 | I32 perl_eval_sv _((SV* sv, I32 flags)); |
1410 | |
1411 | =item perl_free |
1412 | |
1413 | Releases a Perl interpreter. See L<perlembed>. |
1414 | |
1415 | =item perl_get_av |
1416 | |
1417 | Returns the AV of the specified Perl array. If C<create> is set and the |
1418 | Perl variable does not exist then it will be created. If C<create> is not |
1419 | set and the variable does not exist then null is returned. |
1420 | |
1421 | AV* perl_get_av _((char* name, I32 create)); |
1422 | |
1423 | =item perl_get_cv |
1424 | |
1425 | Returns the CV of the specified Perl sub. If C<create> is set and the Perl |
1426 | variable does not exist then it will be created. If C<create> is not |
1427 | set and the variable does not exist then null is returned. |
1428 | |
1429 | CV* perl_get_cv _((char* name, I32 create)); |
1430 | |
1431 | =item perl_get_hv |
1432 | |
1433 | Returns the HV of the specified Perl hash. If C<create> is set and the Perl |
1434 | variable does not exist then it will be created. If C<create> is not |
1435 | set and the variable does not exist then null is returned. |
1436 | |
1437 | HV* perl_get_hv _((char* name, I32 create)); |
1438 | |
1439 | =item perl_get_sv |
1440 | |
1441 | Returns the SV of the specified Perl scalar. If C<create> is set and the |
1442 | Perl variable does not exist then it will be created. If C<create> is not |
1443 | set and the variable does not exist then null is returned. |
1444 | |
1445 | SV* perl_get_sv _((char* name, I32 create)); |
1446 | |
1447 | =item perl_parse |
1448 | |
1449 | Tells a Perl interpreter to parse a Perl script. See L<perlembed>. |
1450 | |
1451 | =item perl_require_pv |
1452 | |
1453 | Tells Perl to C<require> a module. |
1454 | |
1455 | void perl_require_pv _((char* pv)); |
1456 | |
1457 | =item perl_run |
1458 | |
1459 | Tells a Perl interpreter to run. See L<perlembed>. |
1460 | |
1461 | =item POPi |
1462 | |
1463 | Pops an integer off the stack. |
1464 | |
1465 | int POPi(); |
1466 | |
1467 | =item POPl |
1468 | |
1469 | Pops a long off the stack. |
1470 | |
1471 | long POPl(); |
1472 | |
1473 | =item POPp |
1474 | |
1475 | Pops a string off the stack. |
1476 | |
1477 | char * POPp(); |
1478 | |
1479 | =item POPn |
1480 | |
1481 | Pops a double off the stack. |
1482 | |
1483 | double POPn(); |
1484 | |
1485 | =item POPs |
1486 | |
1487 | Pops an SV off the stack. |
1488 | |
1489 | SV* POPs(); |
1490 | |
1491 | =item PUSHMARK |
1492 | |
1493 | Opening bracket for arguments on a callback. See C<PUTBACK> and L<perlcall>. |
1494 | |
1495 | PUSHMARK(p) |
1496 | |
1497 | =item PUSHi |
1498 | |
1499 | Push an integer onto the stack. The stack must have room for this element. |
1500 | See C<XPUSHi>. |
1501 | |
1502 | PUSHi(int d) |
1503 | |
1504 | =item PUSHn |
1505 | |
1506 | Push a double onto the stack. The stack must have room for this element. |
1507 | See C<XPUSHn>. |
1508 | |
1509 | PUSHn(double d) |
1510 | |
1511 | =item PUSHp |
1512 | |
1513 | Push a string onto the stack. The stack must have room for this element. |
1514 | The C<len> indicates the length of the string. See C<XPUSHp>. |
1515 | |
1516 | PUSHp(char *c, int len ) |
1517 | |
1518 | =item PUSHs |
1519 | |
1520 | Push an SV onto the stack. The stack must have room for this element. See |
1521 | C<XPUSHs>. |
1522 | |
1523 | PUSHs(sv) |
1524 | |
1525 | =item PUTBACK |
1526 | |
1527 | Closing bracket for XSUB arguments. This is usually handled by C<xsubpp>. |
1528 | See C<PUSHMARK> and L<perlcall> for other uses. |
1529 | |
1530 | PUTBACK; |
1531 | |
1532 | =item Renew |
1533 | |
1534 | The XSUB-writer's interface to the C C<realloc> function. |
1535 | |
1536 | void * Renew( void *ptr, int size, type ) |
1537 | |
1538 | =item Renewc |
1539 | |
1540 | The XSUB-writer's interface to the C C<realloc> function, with cast. |
1541 | |
1542 | void * Renewc( void *ptr, int size, type, cast ) |
1543 | |
1544 | =item RETVAL |
1545 | |
1546 | Variable which is setup by C<xsubpp> to hold the return value for an XSUB. |
1547 | This is always the proper type for the XSUB. See L<perlxs>. |
1548 | |
1549 | =item safefree |
1550 | |
1551 | The XSUB-writer's interface to the C C<free> function. |
1552 | |
1553 | =item safemalloc |
1554 | |
1555 | The XSUB-writer's interface to the C C<malloc> function. |
1556 | |
1557 | =item saferealloc |
1558 | |
1559 | The XSUB-writer's interface to the C C<realloc> function. |
1560 | |
1561 | =item savepv |
1562 | |
1563 | Copy a string to a safe spot. This does not use an SV. |
1564 | |
1565 | char* savepv _((char* sv)); |
1566 | |
1567 | =item savepvn |
1568 | |
1569 | Copy a string to a safe spot. The C<len> indicates number of bytes to |
1570 | copy. This does not use an SV. |
1571 | |
1572 | char* savepvn _((char* sv, I32 len)); |
1573 | |
1574 | =item SAVETMPS |
1575 | |
1576 | Opening bracket for temporaries on a callback. See C<FREETMPS> and |
1577 | L<perlcall>. |
1578 | |
1579 | SAVETMPS; |
1580 | |
1581 | =item SP |
1582 | |
1583 | Stack pointer. This is usually handled by C<xsubpp>. See C<dSP> and |
1584 | C<SPAGAIN>. |
1585 | |
1586 | =item SPAGAIN |
1587 | |
1588 | Refetch the stack pointer. Used after a callback. See L<perlcall>. |
1589 | |
1590 | SPAGAIN; |
1591 | |
1592 | =item ST |
1593 | |
1594 | Used to access elements on the XSUB's stack. |
1595 | |
1596 | SV* ST(int x) |
1597 | |
1598 | =item strEQ |
1599 | |
1600 | Test two strings to see if they are equal. Returns true or false. |
1601 | |
1602 | int strEQ( char *s1, char *s2 ) |
1603 | |
1604 | =item strGE |
1605 | |
1606 | Test two strings to see if the first, C<s1>, is greater than or equal to the |
1607 | second, C<s2>. Returns true or false. |
1608 | |
1609 | int strGE( char *s1, char *s2 ) |
1610 | |
1611 | =item strGT |
1612 | |
1613 | Test two strings to see if the first, C<s1>, is greater than the second, |
1614 | C<s2>. Returns true or false. |
1615 | |
1616 | int strGT( char *s1, char *s2 ) |
1617 | |
1618 | =item strLE |
1619 | |
1620 | Test two strings to see if the first, C<s1>, is less than or equal to the |
1621 | second, C<s2>. Returns true or false. |
1622 | |
1623 | int strLE( char *s1, char *s2 ) |
1624 | |
1625 | =item strLT |
1626 | |
1627 | Test two strings to see if the first, C<s1>, is less than the second, |
1628 | C<s2>. Returns true or false. |
1629 | |
1630 | int strLT( char *s1, char *s2 ) |
1631 | |
1632 | =item strNE |
1633 | |
1634 | Test two strings to see if they are different. Returns true or false. |
1635 | |
1636 | int strNE( char *s1, char *s2 ) |
1637 | |
1638 | =item strnEQ |
1639 | |
1640 | Test two strings to see if they are equal. The C<len> parameter indicates |
1641 | the number of bytes to compare. Returns true or false. |
1642 | |
1643 | int strnEQ( char *s1, char *s2 ) |
1644 | |
1645 | =item strnNE |
1646 | |
1647 | Test two strings to see if they are different. The C<len> parameter |
1648 | indicates the number of bytes to compare. Returns true or false. |
1649 | |
1650 | int strnNE( char *s1, char *s2, int len ) |
1651 | |
1652 | =item sv_2mortal |
1653 | |
1654 | Marks an SV as mortal. The SV will be destroyed when the current context |
1655 | ends. |
1656 | |
1657 | SV* sv_2mortal _((SV* sv)); |
1658 | |
1659 | =item sv_bless |
1660 | |
1661 | Blesses an SV into a specified package. The SV must be an RV. The package |
1662 | must be designated by its stash (see C<gv_stashpv()>). The refcount of the |
1663 | SV is unaffected. |
1664 | |
1665 | SV* sv_bless _((SV* sv, HV* stash)); |
1666 | |
1667 | =item sv_catpv |
1668 | |
1669 | Concatenates the string onto the end of the string which is in the SV. |
1670 | |
1671 | void sv_catpv _((SV* sv, char* ptr)); |
1672 | |
1673 | =item sv_catpvn |
1674 | |
1675 | Concatenates the string onto the end of the string which is in the SV. The |
1676 | C<len> indicates number of bytes to copy. |
1677 | |
1678 | void sv_catpvn _((SV* sv, char* ptr, STRLEN len)); |
1679 | |
1680 | =item sv_catsv |
1681 | |
1682 | Concatentates the string from SV C<ssv> onto the end of the string in SV |
1683 | C<dsv>. |
1684 | |
1685 | void sv_catsv _((SV* dsv, SV* ssv)); |
1686 | |
1687 | =item SvCUR |
1688 | |
1689 | Returns the length of the string which is in the SV. See C<SvLEN>. |
1690 | |
1691 | int SvCUR (SV* sv) |
1692 | |
1693 | =item SvCUR_set |
1694 | |
1695 | Set the length of the string which is in the SV. See C<SvCUR>. |
1696 | |
1697 | SvCUR_set (SV* sv, int val ) |
1698 | |
1699 | =item SvEND |
1700 | |
1701 | Returns a pointer to the last character in the string which is in the SV. |
1702 | See C<SvCUR>. Access the character as |
1703 | |
1704 | *SvEND(sv) |
1705 | |
1706 | =item SvGROW |
1707 | |
1708 | Expands the character buffer in the SV. |
1709 | |
1710 | char * SvGROW( SV* sv, int len ) |
1711 | |
1712 | =item SvIOK |
1713 | |
1714 | Returns a boolean indicating whether the SV contains an integer. |
1715 | |
1716 | int SvIOK (SV* SV) |
1717 | |
1718 | =item SvIOK_off |
1719 | |
1720 | Unsets the IV status of an SV. |
1721 | |
1722 | SvIOK_off (SV* sv) |
1723 | |
1724 | =item SvIOK_on |
1725 | |
1726 | Tells an SV that it is an integer. |
1727 | |
1728 | SvIOK_on (SV* sv) |
1729 | |
1730 | =item SvIOKp |
1731 | |
1732 | Returns a boolean indicating whether the SV contains an integer. Checks the |
1733 | B<private> setting. Use C<SvIOK>. |
1734 | |
1735 | int SvIOKp (SV* SV) |
1736 | |
1737 | =item sv_isa |
1738 | |
1739 | Returns a boolean indicating whether the SV is blessed into the specified |
1740 | class. This does not know how to check for subtype, so it doesn't work in |
1741 | an inheritance relationship. |
1742 | |
1743 | int sv_isa _((SV* sv, char* name)); |
1744 | |
1745 | =item SvIV |
1746 | |
1747 | Returns the integer which is in the SV. |
1748 | |
1749 | int SvIV (SV* sv) |
1750 | |
1751 | =item sv_isobject |
1752 | |
1753 | Returns a boolean indicating whether the SV is an RV pointing to a blessed |
1754 | object. If the SV is not an RV, or if the object is not blessed, then this |
1755 | will return false. |
1756 | |
1757 | int sv_isobject _((SV* sv)); |
1758 | |
1759 | =item SvIVX |
1760 | |
1761 | Returns the integer which is stored in the SV. |
1762 | |
1763 | int SvIVX (SV* sv); |
1764 | |
1765 | =item SvLEN |
1766 | |
1767 | Returns the size of the string buffer in the SV. See C<SvCUR>. |
1768 | |
1769 | int SvLEN (SV* sv) |
1770 | |
1771 | =item sv_magic |
1772 | |
1773 | Adds magic to an SV. |
1774 | |
1775 | void sv_magic _((SV* sv, SV* obj, int how, char* name, I32 namlen)); |
1776 | |
1777 | =item sv_mortalcopy |
1778 | |
1779 | Creates a new SV which is a copy of the original SV. The new SV is marked |
1780 | as mortal. |
1781 | |
1782 | SV* sv_mortalcopy _((SV* oldsv)); |
1783 | |
1784 | =item SvOK |
1785 | |
1786 | Returns a boolean indicating whether the value is an SV. |
1787 | |
1788 | int SvOK (SV* sv) |
1789 | |
1790 | =item sv_newmortal |
1791 | |
1792 | Creates a new SV which is mortal. The refcount of the SV is set to 1. |
1793 | |
1794 | SV* sv_newmortal _((void)); |
1795 | |
1796 | =item sv_no |
1797 | |
1798 | This is the C<false> SV. See C<sv_yes>. Always refer to this as C<&sv_no>. |
1799 | |
1800 | =item SvNIOK |
1801 | |
1802 | Returns a boolean indicating whether the SV contains a number, integer or |
1803 | double. |
1804 | |
1805 | int SvNIOK (SV* SV) |
1806 | |
1807 | =item SvNIOK_off |
1808 | |
1809 | Unsets the NV/IV status of an SV. |
1810 | |
1811 | SvNIOK_off (SV* sv) |
1812 | |
1813 | =item SvNIOKp |
1814 | |
1815 | Returns a boolean indicating whether the SV contains a number, integer or |
1816 | double. Checks the B<private> setting. Use C<SvNIOK>. |
1817 | |
1818 | int SvNIOKp (SV* SV) |
1819 | |
1820 | =item SvNOK |
1821 | |
1822 | Returns a boolean indicating whether the SV contains a double. |
1823 | |
1824 | int SvNOK (SV* SV) |
1825 | |
1826 | =item SvNOK_off |
1827 | |
1828 | Unsets the NV status of an SV. |
1829 | |
1830 | SvNOK_off (SV* sv) |
1831 | |
1832 | =item SvNOK_on |
1833 | |
1834 | Tells an SV that it is a double. |
1835 | |
1836 | SvNOK_on (SV* sv) |
1837 | |
1838 | =item SvNOKp |
1839 | |
1840 | Returns a boolean indicating whether the SV contains a double. Checks the |
1841 | B<private> setting. Use C<SvNOK>. |
1842 | |
1843 | int SvNOKp (SV* SV) |
1844 | |
1845 | =item SvNV |
1846 | |
1847 | Returns the double which is stored in the SV. |
1848 | |
1849 | double SvNV (SV* sv); |
1850 | |
1851 | =item SvNVX |
1852 | |
1853 | Returns the double which is stored in the SV. |
1854 | |
1855 | double SvNVX (SV* sv); |
1856 | |
1857 | =item SvPOK |
1858 | |
1859 | Returns a boolean indicating whether the SV contains a character string. |
1860 | |
1861 | int SvPOK (SV* SV) |
1862 | |
1863 | =item SvPOK_off |
1864 | |
1865 | Unsets the PV status of an SV. |
1866 | |
1867 | SvPOK_off (SV* sv) |
1868 | |
1869 | =item SvPOK_on |
1870 | |
1871 | Tells an SV that it is a string. |
1872 | |
1873 | SvPOK_on (SV* sv) |
1874 | |
1875 | =item SvPOKp |
1876 | |
1877 | Returns a boolean indicating whether the SV contains a character string. |
1878 | Checks the B<private> setting. Use C<SvPOK>. |
1879 | |
1880 | int SvPOKp (SV* SV) |
1881 | |
1882 | =item SvPV |
1883 | |
1884 | Returns a pointer to the string in the SV, or a stringified form of the SV |
1885 | if the SV does not contain a string. If C<len> is C<na> then Perl will |
1886 | handle the length on its own. |
1887 | |
1888 | char * SvPV (SV* sv, int len ) |
1889 | |
1890 | =item SvPVX |
1891 | |
1892 | Returns a pointer to the string in the SV. The SV must contain a string. |
1893 | |
1894 | char * SvPVX (SV* sv) |
1895 | |
1896 | =item SvREFCNT |
1897 | |
1898 | Returns the value of the object's refcount. |
1899 | |
1900 | int SvREFCNT (SV* sv); |
1901 | |
1902 | =item SvREFCNT_dec |
1903 | |
1904 | Decrements the refcount of the given SV. |
1905 | |
1906 | void SvREFCNT_dec (SV* sv) |
1907 | |
1908 | =item SvREFCNT_inc |
1909 | |
1910 | Increments the refcount of the given SV. |
1911 | |
1912 | void SvREFCNT_inc (SV* sv) |
1913 | |
1914 | =item SvROK |
1915 | |
1916 | Tests if the SV is an RV. |
1917 | |
1918 | int SvROK (SV* sv) |
1919 | |
1920 | =item SvROK_off |
1921 | |
1922 | Unsets the RV status of an SV. |
1923 | |
1924 | SvROK_off (SV* sv) |
1925 | |
1926 | =item SvROK_on |
1927 | |
1928 | Tells an SV that it is an RV. |
1929 | |
1930 | SvROK_on (SV* sv) |
1931 | |
1932 | =item SvRV |
1933 | |
1934 | Dereferences an RV to return the SV. |
1935 | |
1936 | SV* SvRV (SV* sv); |
1937 | |
1938 | =item sv_setiv |
1939 | |
1940 | Copies an integer into the given SV. |
1941 | |
1942 | void sv_setiv _((SV* sv, IV num)); |
1943 | |
1944 | =item sv_setnv |
1945 | |
1946 | Copies a double into the given SV. |
1947 | |
1948 | void sv_setnv _((SV* sv, double num)); |
1949 | |
1950 | =item sv_setpv |
1951 | |
1952 | Copies a string into an SV. The string must be null-terminated. |
1953 | |
1954 | void sv_setpv _((SV* sv, char* ptr)); |
1955 | |
1956 | =item sv_setpvn |
1957 | |
1958 | Copies a string into an SV. The C<len> parameter indicates the number of |
1959 | bytes to be copied. |
1960 | |
1961 | void sv_setpvn _((SV* sv, char* ptr, STRLEN len)); |
1962 | |
1963 | =item sv_setref_iv |
1964 | |
1965 | Copies an integer into an SV, optionally blessing the SV. The SV must be an |
1966 | RV. The C<classname> argument indicates the package for the blessing. Set |
1967 | C<classname> to C<Nullch> to avoid the blessing. The new SV will be |
1968 | returned and will have a refcount of 1. |
1969 | |
1970 | SV* sv_setref_iv _((SV *rv, char *classname, IV iv)); |
1971 | |
1972 | =item sv_setref_nv |
1973 | |
1974 | Copies a double into an SV, optionally blessing the SV. The SV must be an |
1975 | RV. The C<classname> argument indicates the package for the blessing. Set |
1976 | C<classname> to C<Nullch> to avoid the blessing. The new SV will be |
1977 | returned and will have a refcount of 1. |
1978 | |
1979 | SV* sv_setref_nv _((SV *rv, char *classname, double nv)); |
1980 | |
1981 | =item sv_setref_pv |
1982 | |
1983 | Copies a pointer into an SV, optionally blessing the SV. The SV must be an |
1984 | RV. If the C<pv> argument is NULL then C<sv_undef> will be placed into the |
1985 | SV. The C<classname> argument indicates the package for the blessing. Set |
1986 | C<classname> to C<Nullch> to avoid the blessing. The new SV will be |
1987 | returned and will have a refcount of 1. |
1988 | |
1989 | SV* sv_setref_pv _((SV *rv, char *classname, void* pv)); |
1990 | |
1991 | Do not use with integral Perl types such as HV, AV, SV, CV, because those |
1992 | objects will become corrupted by the pointer copy process. |
1993 | |
1994 | Note that C<sv_setref_pvn> copies the string while this copies the pointer. |
1995 | |
1996 | =item sv_setref_pvn |
1997 | |
1998 | Copies a string into an SV, optionally blessing the SV. The lenth of the |
1999 | string must be specified with C<n>. The SV must be an RV. The C<classname> |
2000 | argument indicates the package for the blessing. Set C<classname> to |
2001 | C<Nullch> to avoid the blessing. The new SV will be returned and will have |
2002 | a refcount of 1. |
2003 | |
2004 | SV* sv_setref_pvn _((SV *rv, char *classname, char* pv, I32 n)); |
2005 | |
2006 | Note that C<sv_setref_pv> copies the pointer while this copies the string. |
2007 | |
2008 | =item sv_setsv |
2009 | |
2010 | Copies the contents of the source SV C<ssv> into the destination SV C<dsv>. |
1faa3dee |
2011 | (B<NOTE:> If C<ssv> has the C<SVs_TEMP> bit set, C<sv_setsv> may simply steal |
2012 | the string from C<ssv> and give it to C<dsv>, leaving C<ssv> empty. |
2013 | Caveat caller.) |
cb1a09d0 |
2014 | |
2015 | void sv_setsv _((SV* dsv, SV* ssv)); |
2016 | |
2017 | =item SvSTASH |
2018 | |
2019 | Returns the stash of the SV. |
2020 | |
2021 | HV * SvSTASH (SV* sv) |
2022 | |
2023 | =item SVt_IV |
2024 | |
2025 | Integer type flag for scalars. See C<svtype>. |
2026 | |
2027 | =item SVt_PV |
2028 | |
2029 | Pointer type flag for scalars. See C<svtype>. |
2030 | |
2031 | =item SVt_PVAV |
2032 | |
2033 | Type flag for arrays. See C<svtype>. |
2034 | |
2035 | =item SVt_PVCV |
2036 | |
2037 | Type flag for code refs. See C<svtype>. |
2038 | |
2039 | =item SVt_PVHV |
2040 | |
2041 | Type flag for hashes. See C<svtype>. |
2042 | |
2043 | =item SVt_PVMG |
2044 | |
2045 | Type flag for blessed scalars. See C<svtype>. |
2046 | |
2047 | =item SVt_NV |
2048 | |
2049 | Double type flag for scalars. See C<svtype>. |
2050 | |
2051 | =item SvTRUE |
2052 | |
2053 | Returns a boolean indicating whether Perl would evaluate the SV as true or |
2054 | false, defined or undefined. |
2055 | |
2056 | int SvTRUE (SV* sv) |
2057 | |
2058 | =item SvTYPE |
2059 | |
2060 | Returns the type of the SV. See C<svtype>. |
2061 | |
2062 | svtype SvTYPE (SV* sv) |
2063 | |
2064 | =item svtype |
2065 | |
2066 | An enum of flags for Perl types. These are found in the file B<sv.h> in the |
2067 | C<svtype> enum. Test these flags with the C<SvTYPE> macro. |
2068 | |
2069 | =item SvUPGRADE |
2070 | |
2071 | Used to upgrade an SV to a more complex form. See C<svtype>. |
2072 | |
2073 | =item sv_undef |
2074 | |
2075 | This is the C<undef> SV. Always refer to this as C<&sv_undef>. |
2076 | |
2077 | =item sv_usepvn |
2078 | |
2079 | Tells an SV to use C<ptr> to find its string value. Normally the string is |
2080 | stored inside the SV; this allows the SV to use an outside string. The |
2081 | string length, C<len>, must be supplied. This function will realloc the |
2082 | memory pointed to by C<ptr>, so that pointer should not be freed or used by |
2083 | the programmer after giving it to sv_usepvn. |
2084 | |
2085 | void sv_usepvn _((SV* sv, char* ptr, STRLEN len)); |
2086 | |
2087 | =item sv_yes |
2088 | |
2089 | This is the C<true> SV. See C<sv_no>. Always refer to this as C<&sv_yes>. |
2090 | |
2091 | =item THIS |
2092 | |
2093 | Variable which is setup by C<xsubpp> to designate the object in a C++ XSUB. |
2094 | This is always the proper type for the C++ object. See C<CLASS> and |
2095 | L<perlxs>. |
2096 | |
2097 | =item toLOWER |
2098 | |
2099 | Converts the specified character to lowercase. |
2100 | |
2101 | int toLOWER (char c) |
2102 | |
2103 | =item toUPPER |
2104 | |
2105 | Converts the specified character to uppercase. |
2106 | |
2107 | int toUPPER (char c) |
2108 | |
2109 | =item warn |
2110 | |
2111 | This is the XSUB-writer's interface to Perl's C<warn> function. Use this |
2112 | function the same way you use the C C<printf> function. See C<croak()>. |
2113 | |
2114 | =item XPUSHi |
2115 | |
2116 | Push an integer onto the stack, extending the stack if necessary. See |
2117 | C<PUSHi>. |
2118 | |
2119 | XPUSHi(int d) |
2120 | |
2121 | =item XPUSHn |
2122 | |
2123 | Push a double onto the stack, extending the stack if necessary. See |
2124 | C<PUSHn>. |
2125 | |
2126 | XPUSHn(double d) |
2127 | |
2128 | =item XPUSHp |
2129 | |
2130 | Push a string onto the stack, extending the stack if necessary. The C<len> |
2131 | indicates the length of the string. See C<PUSHp>. |
2132 | |
2133 | XPUSHp(char *c, int len) |
2134 | |
2135 | =item XPUSHs |
2136 | |
2137 | Push an SV onto the stack, extending the stack if necessary. See C<PUSHs>. |
2138 | |
2139 | XPUSHs(sv) |
2140 | |
2141 | =item XSRETURN |
2142 | |
2143 | Return from XSUB, indicating number of items on the stack. This is usually |
2144 | handled by C<xsubpp>. |
2145 | |
2146 | XSRETURN(x); |
2147 | |
2148 | =item XSRETURN_EMPTY |
2149 | |
2150 | Return from an XSUB immediately. |
2151 | |
2152 | XSRETURN_EMPTY; |
2153 | |
2154 | =item XSRETURN_NO |
2155 | |
2156 | Return C<false> from an XSUB immediately. |
2157 | |
2158 | XSRETURN_NO; |
2159 | |
2160 | =item XSRETURN_UNDEF |
2161 | |
2162 | Return C<undef> from an XSUB immediately. |
2163 | |
2164 | XSRETURN_UNDEF; |
2165 | |
2166 | =item XSRETURN_YES |
2167 | |
2168 | Return C<true> from an XSUB immediately. |
2169 | |
2170 | XSRETURN_YES; |
2171 | |
2172 | =item Zero |
2173 | |
2174 | The XSUB-writer's interface to the C C<memzero> function. The C<d> is the |
2175 | destination, C<n> is the number of items, and C<t> is the type. |
2176 | |
2177 | (void) Zero( d, n, t ); |
2178 | |
2179 | =back |
2180 | |
2181 | =head1 AUTHOR |
2182 | |
2183 | Jeff Okamoto <okamoto@corp.hp.com> |
2184 | |
2185 | With lots of help and suggestions from Dean Roehrich, Malcolm Beattie, |
2186 | Andreas Koenig, Paul Hudson, Ilya Zakharevich, Paul Marquess, Neil |
2187 | Bowers, Matthew Green, Tim Bunce, and Spider Boardman. |
2188 | |
2189 | API Listing by Dean Roehrich <roehrich@cray.com>. |
2190 | |
2191 | =head1 DATE |
2192 | |
2193 | Version 20: 1995/12/14 |
a0d0e21e |
2194 | |