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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 | |
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29 | =head2 Working with SVs |
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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 *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 |
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70 | NULs and not be terminated by a NUL. |
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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, |
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149 | bus error, or just plain weird results. Change the zero to C<&sv_undef> in |
150 | the first line and all will be well. |
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151 | |
152 | To free an SV that you've created, call C<SvREFCNT_dec(SV*)>. Normally this |
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153 | call is not necessary. See the section on L<Mortality>. |
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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 | |
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175 | =head2 Working with AVs |
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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 | |
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182 | The second method both creates the AV and initially populates it with SVs: |
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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 SVs can be destroyed, if so desired. |
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188 | |
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189 | Once the AV has been created, the following operations are possible on AVs: |
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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 | |
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227 | =head2 Working with HVs |
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228 | |
229 | To create an HV, you use the following routine: |
230 | |
231 | HV* newHV(); |
232 | |
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233 | Once the HV has been created, the following operations are possible on HVs: |
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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 | |
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244 | Remember that C<hv_store> and C<hv_fetch> return C<SV**>s and not just |
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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 |
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348 | which class the reference will belong to. See the section on L<Stashes> |
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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 |
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396 | "Identifier <varname> used only once: possible typo" warning. |
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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 XSUBs 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 |
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431 | macros to push IVs, doubles, strings, and SV pointers respectively: |
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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 | |
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451 | These macros automatically adjust the stack for you, if needed. Thus, you |
452 | do not need to call C<EXTEND> to extend the stack. |
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453 | |
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454 | For more information, consult L<perlxs>. |
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455 | |
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456 | =head1 Localizing Changes |
457 | |
458 | Perl has a very handy construction |
459 | |
460 | { |
461 | local $var = 2; |
462 | ... |
463 | } |
464 | |
465 | This construction is I<approximately> equivalent to |
466 | |
467 | { |
468 | my $oldvar = $var; |
469 | $var = 2; |
470 | ... |
471 | $var = $oldvar; |
472 | } |
473 | |
474 | The biggest difference is that the first construction would would |
475 | reinstate the initial value of $var, irrespective of how control exits |
476 | the block: C<goto>, C<return>, C<die>/C<eval> etc. It is a little bit |
477 | more efficient as well. |
478 | |
479 | There is a way to achieve a similar task from C via Perl API: create a |
480 | I<pseudo-block>, and arrange for some changes to be automatically |
481 | undone at the end of it, either explicit, or via a non-local exit (via |
482 | die()). A I<block>-like construct is created by a pair of |
483 | C<ENTER>/C<LEAVE> macros (see L<perlcall/EXAMPLE/"Returning a |
484 | Scalar">). Such a construct may be created specially for some |
485 | important localized task, or an existing one (like boundaries of |
486 | enclosing Perl subroutine/block, or an existing pair for freeing TMPs) |
487 | may be used. (In the second case the overhead of additional |
488 | localization must be almost negligible.) Note that any XSUB is |
489 | automatically enclosed in an C<ENTER>/C<LEAVE> pair. |
490 | |
491 | Inside such a I<pseudo-block> the following service is available: |
492 | |
493 | =over |
494 | |
495 | =item C<SAVEINT(int i)> |
496 | |
497 | =item C<SAVEIV(IV i)> |
498 | |
499 | =item C<SAVEI16(I16 i)> |
500 | |
501 | =item C<SAVEI32(I32 i)> |
502 | |
503 | =item C<SAVELONG(long i)> |
504 | |
505 | These macros arrange things to restore the value of integer variable |
506 | C<i> at the end of enclosing I<pseudo-block>. |
507 | |
508 | =item C<SAVESPTR(p)> |
509 | |
510 | =item C<SAVEPPTR(s)> |
511 | |
512 | These macros arrange things to restore the value of pointers C<s> and |
513 | C<p>. C<p> must be a pointer of a type which survives conversion to |
514 | C<SV*> and back, C<s> should be able to survive conversion to C<char*> |
515 | and back. |
516 | |
517 | =item C<SAVEFREESV(SV *sv)> |
518 | |
519 | The refcount of C<sv> would be decremented at the end of |
520 | I<pseudo-block>. This is similar to C<sv_2mortal>, which should (?) be |
521 | used instead. |
522 | |
523 | =item C<SAVEFREEOP(OP *op)> |
524 | |
525 | The C<OP *> is op_free()ed at the end of I<pseudo-block>. |
526 | |
527 | =item C<SAVEFREEPV(p)> |
528 | |
529 | The chunk of memory which is pointed to by C<p> is Safefree()ed at the |
530 | end of I<pseudo-block>. |
531 | |
532 | =item C<SAVECLEARSV(SV *sv)> |
533 | |
534 | Clears a slot in the current scratchpad which corresponds to C<sv> at |
535 | the end of I<pseudo-block>. |
536 | |
537 | =item C<SAVEDELETE(HV *hv, char *key, I32 length)> |
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538 | |
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539 | The key C<key> of C<hv> is deleted at the end of I<pseudo-block>. The |
540 | string pointed to by C<key> is Safefree()ed. If one has a I<key> in |
541 | short-lived storage, the corresponding string may be reallocated like |
542 | this: |
a0d0e21e |
543 | |
55497cff |
544 | SAVEDELETE(defstash, savepv(tmpbuf), strlen(tmpbuf)); |
d1b91892 |
545 | |
55497cff |
546 | =item C<SAVEDESTRUCTOR(f,p)> |
547 | |
548 | At the end of I<pseudo-block> the function C<f> is called with the |
549 | only argument (of type C<void*>) C<p>. |
550 | |
551 | =item C<SAVESTACK_POS()> |
552 | |
553 | The current offset on the Perl internal stack (cf. C<SP>) is restored |
554 | at the end of I<pseudo-block>. |
555 | |
556 | =back |
557 | |
558 | The following API list contains functions, thus one needs to |
559 | provide pointers to the modifiable data explicitly (either C pointers, |
560 | or Perlish C<GV *>s): |
561 | |
562 | =over |
563 | |
564 | =item C<SV* save_scalar(GV *gv)> |
565 | |
566 | Equivalent to Perl code C<local $gv>. |
567 | |
568 | =item C<AV* save_ary(GV *gv)> |
569 | |
570 | =item C<HV* save_hash(GV *gv)> |
571 | |
572 | Similar to C<save_scalar>, but localize C<@gv> and C<%gv>. |
573 | |
574 | =item C<void save_item(SV *item)> |
575 | |
576 | Duplicates the current value of C<SV>, on the exit from the current |
577 | C<ENTER>/C<LEAVE> I<pseudo-block> will restore the value of C<SV> |
578 | using the stored value. |
579 | |
580 | =item C<void save_list(SV **sarg, I32 maxsarg)> |
581 | |
582 | A variant of C<save_item> which takes multiple arguments via an array |
583 | C<sarg> of C<SV*> of length C<maxsarg>. |
584 | |
585 | =item C<SV* save_svref(SV **sptr)> |
586 | |
587 | Similar to C<save_scalar>, but will reinstate a C<SV *>. |
588 | |
589 | =item C<void save_aptr(AV **aptr)> |
590 | |
591 | =item C<void save_hptr(HV **hptr)> |
592 | |
593 | Similar to C<save_svref>, but localize C<AV *> and C<HV *>. |
594 | |
595 | =item C<void save_nogv(GV *gv)> |
596 | |
597 | Will postpone destruction of a I<stub> glob. |
598 | |
599 | =back |
600 | |
601 | =head1 Mortality |
a0d0e21e |
602 | |
55497cff |
603 | Perl uses an reference count-driven garbage collection mechanism. SV's, |
604 | AV's, or HV's (xV for short in the following) start their life with a |
605 | reference count of 1. If the reference count of an xV ever drops to 0, |
606 | then they will be destroyed and their memory made available for reuse. |
607 | |
608 | This normally doesn't happen at the Perl level unless a variable is |
609 | undef'ed. At the internal level, however, reference counts can be |
610 | manipulated with the following macros: |
611 | |
612 | int SvREFCNT(SV* sv); |
613 | void SvREFCNT_inc(SV* sv); |
614 | void SvREFCNT_dec(SV* sv); |
615 | |
616 | However, there is one other function which manipulates the reference |
617 | count of its argument. The C<newRV> function, as you should recall, |
618 | creates a reference to the specified argument. As a side effect, it |
619 | increments the argument's reference count, which is ok in most |
620 | circumstances. But imagine you want to return a reference from an XS |
621 | function. You create a new SV which initially has a reference count |
622 | of 1. Then you call C<newRV>, passing the just-created SV. This returns |
623 | the reference as a new SV, but the reference count of the SV you passed |
624 | to C<newRV> has been incremented to 2. Now you return the reference and |
625 | forget about the SV. But Perl hasn't! Whenever the returned reference |
626 | is destroyed, the reference count of the original SV is decreased to 1 |
627 | and nothing happens. The SV will hang around without any way to access |
628 | it until Perl itself terminates. This is a memory leak. |
629 | |
630 | The correct procedure, then, is to call C<SvREFCNT_dec> on the SV after |
631 | C<newRV> has returned. Then, if and when the reference is destroyed, |
632 | the reference count of the SV will go to 0 and also be destroyed, stopping |
633 | any memory leak. |
634 | |
635 | There are some convenience functions available that can help with this |
636 | process. These functions introduce the concept of "mortality". An xV |
637 | that is mortal has had its reference count marked to be decremented, |
638 | but not actually decremented, until the "current context" is left. |
639 | Generally the "current context" means a single Perl statement, such as |
640 | a call to an XSUB function. |
641 | |
642 | "Mortalization" then is at its simplest a deferred C<SvREFCNT_dec>. |
643 | However, if you mortalize a variable twice, the reference count will |
644 | later be decremented twice. |
645 | |
646 | You should be careful about creating mortal variables. Strange things |
647 | can happen if you make the same value mortal within multiple contexts, |
648 | or if you make a variable mortal multiple times. Doing the latter can |
649 | cause a variable to become invalid prematurely. |
a0d0e21e |
650 | |
651 | To create a mortal variable, use the functions: |
652 | |
653 | SV* sv_newmortal() |
654 | SV* sv_2mortal(SV*) |
655 | SV* sv_mortalcopy(SV*) |
656 | |
657 | The first call creates a mortal SV, the second converts an existing SV to |
658 | a mortal SV, the third creates a mortal copy of an existing SV. |
659 | |
5fb8527f |
660 | The mortal routines are not just for SVs -- AVs and HVs can be made mortal |
a0d0e21e |
661 | by passing their address (and casting them to C<SV*>) to the C<sv_2mortal> or |
662 | C<sv_mortalcopy> routines. |
663 | |
55497cff |
664 | I<From Ilya:> |
d1b91892 |
665 | Beware that the sv_2mortal() call is eventually equivalent to |
666 | svREFCNT_dec(). A value can happily be mortal in two different contexts, |
667 | and it will be svREFCNT_dec()ed twice, once on exit from these |
668 | contexts. It can also be mortal twice in the same context. This means |
669 | that you should be very careful to make a value mortal exactly as many |
670 | times as it is needed. The value that go to the Perl stack I<should> |
671 | be mortal. |
a0d0e21e |
672 | |
a0d0e21e |
673 | |
cb1a09d0 |
674 | =head1 Stashes |
a0d0e21e |
675 | |
676 | A stash is a hash table (associative array) that contains all of the |
677 | different objects that are contained within a package. Each key of the |
d1b91892 |
678 | stash is a symbol name (shared by all the different types of objects |
679 | that have the same name), and each value in the hash table is called a |
680 | GV (for Glob Value). This GV in turn contains references to the various |
681 | objects of that name, including (but not limited to) the following: |
cb1a09d0 |
682 | |
a0d0e21e |
683 | Scalar Value |
684 | Array Value |
685 | Hash Value |
686 | File Handle |
687 | Directory Handle |
688 | Format |
689 | Subroutine |
690 | |
d1b91892 |
691 | Perl stores various stashes in a separate GV structure (for global |
692 | variable) but represents them with an HV structure. The keys in this |
5fb8527f |
693 | larger GV are the various package names; the values are the C<GV*>s |
d1b91892 |
694 | which are stashes. It may help to think of a stash purely as an HV, |
695 | and that the term "GV" means the global variable hash. |
a0d0e21e |
696 | |
d1b91892 |
697 | To get the stash pointer for a particular package, use the function: |
a0d0e21e |
698 | |
699 | HV* gv_stashpv(char* name, I32 create) |
700 | HV* gv_stashsv(SV*, I32 create) |
701 | |
702 | The first function takes a literal string, the second uses the string stored |
d1b91892 |
703 | in the SV. Remember that a stash is just a hash table, so you get back an |
cb1a09d0 |
704 | C<HV*>. The C<create> flag will create a new package if it is set. |
a0d0e21e |
705 | |
706 | The name that C<gv_stash*v> wants is the name of the package whose symbol table |
707 | you want. The default package is called C<main>. If you have multiply nested |
d1b91892 |
708 | packages, pass their names to C<gv_stash*v>, separated by C<::> as in the Perl |
709 | language itself. |
a0d0e21e |
710 | |
711 | Alternately, if you have an SV that is a blessed reference, you can find |
712 | out the stash pointer by using: |
713 | |
714 | HV* SvSTASH(SvRV(SV*)); |
715 | |
716 | then use the following to get the package name itself: |
717 | |
718 | char* HvNAME(HV* stash); |
719 | |
720 | If you need to return a blessed value to your Perl script, you can use the |
721 | following function: |
722 | |
723 | SV* sv_bless(SV*, HV* stash) |
724 | |
725 | where the first argument, an C<SV*>, must be a reference, and the second |
726 | argument is a stash. The returned C<SV*> can now be used in the same way |
727 | as any other SV. |
728 | |
d1b91892 |
729 | For more information on references and blessings, consult L<perlref>. |
730 | |
a0d0e21e |
731 | =head1 Magic |
732 | |
d1b91892 |
733 | [This section still under construction. Ignore everything here. Post no |
734 | bills. Everything not permitted is forbidden.] |
735 | |
d1b91892 |
736 | Any SV may be magical, that is, it has special features that a normal |
737 | SV does not have. These features are stored in the SV structure in a |
5fb8527f |
738 | linked list of C<struct magic>s, typedef'ed to C<MAGIC>. |
d1b91892 |
739 | |
740 | struct magic { |
741 | MAGIC* mg_moremagic; |
742 | MGVTBL* mg_virtual; |
743 | U16 mg_private; |
744 | char mg_type; |
745 | U8 mg_flags; |
746 | SV* mg_obj; |
747 | char* mg_ptr; |
748 | I32 mg_len; |
749 | }; |
750 | |
751 | Note this is current as of patchlevel 0, and could change at any time. |
752 | |
753 | =head2 Assigning Magic |
754 | |
755 | Perl adds magic to an SV using the sv_magic function: |
756 | |
757 | void sv_magic(SV* sv, SV* obj, int how, char* name, I32 namlen); |
758 | |
759 | The C<sv> argument is a pointer to the SV that is to acquire a new magical |
760 | feature. |
761 | |
762 | If C<sv> is not already magical, Perl uses the C<SvUPGRADE> macro to |
763 | set the C<SVt_PVMG> flag for the C<sv>. Perl then continues by adding |
764 | it to the beginning of the linked list of magical features. Any prior |
765 | entry of the same type of magic is deleted. Note that this can be |
5fb8527f |
766 | overridden, and multiple instances of the same type of magic can be |
d1b91892 |
767 | associated with an SV. |
768 | |
769 | The C<name> and C<namlem> arguments are used to associate a string with |
770 | the magic, typically the name of a variable. C<namlem> is stored in the |
55497cff |
771 | C<mg_len> field and if C<name> is non-null and C<namlem> >= 0 a malloc'd |
d1b91892 |
772 | copy of the name is stored in C<mg_ptr> field. |
773 | |
774 | The sv_magic function uses C<how> to determine which, if any, predefined |
775 | "Magic Virtual Table" should be assigned to the C<mg_virtual> field. |
cb1a09d0 |
776 | See the "Magic Virtual Table" section below. The C<how> argument is also |
777 | stored in the C<mg_type> field. |
d1b91892 |
778 | |
779 | The C<obj> argument is stored in the C<mg_obj> field of the C<MAGIC> |
780 | structure. If it is not the same as the C<sv> argument, the reference |
781 | count of the C<obj> object is incremented. If it is the same, or if |
782 | the C<how> argument is "#", or if it is a null pointer, then C<obj> is |
783 | merely stored, without the reference count being incremented. |
784 | |
cb1a09d0 |
785 | There is also a function to add magic to an C<HV>: |
786 | |
787 | void hv_magic(HV *hv, GV *gv, int how); |
788 | |
789 | This simply calls C<sv_magic> and coerces the C<gv> argument into an C<SV>. |
790 | |
791 | To remove the magic from an SV, call the function sv_unmagic: |
792 | |
793 | void sv_unmagic(SV *sv, int type); |
794 | |
795 | The C<type> argument should be equal to the C<how> value when the C<SV> |
796 | was initially made magical. |
797 | |
d1b91892 |
798 | =head2 Magic Virtual Tables |
799 | |
800 | The C<mg_virtual> field in the C<MAGIC> structure is a pointer to a |
801 | C<MGVTBL>, which is a structure of function pointers and stands for |
802 | "Magic Virtual Table" to handle the various operations that might be |
803 | applied to that variable. |
804 | |
805 | The C<MGVTBL> has five pointers to the following routine types: |
806 | |
807 | int (*svt_get)(SV* sv, MAGIC* mg); |
808 | int (*svt_set)(SV* sv, MAGIC* mg); |
809 | U32 (*svt_len)(SV* sv, MAGIC* mg); |
810 | int (*svt_clear)(SV* sv, MAGIC* mg); |
811 | int (*svt_free)(SV* sv, MAGIC* mg); |
812 | |
813 | This MGVTBL structure is set at compile-time in C<perl.h> and there are |
814 | currently 19 types (or 21 with overloading turned on). These different |
815 | structures contain pointers to various routines that perform additional |
816 | actions depending on which function is being called. |
817 | |
818 | Function pointer Action taken |
819 | ---------------- ------------ |
820 | svt_get Do something after the value of the SV is retrieved. |
821 | svt_set Do something after the SV is assigned a value. |
822 | svt_len Report on the SV's length. |
823 | svt_clear Clear something the SV represents. |
824 | svt_free Free any extra storage associated with the SV. |
825 | |
826 | For instance, the MGVTBL structure called C<vtbl_sv> (which corresponds |
827 | to an C<mg_type> of '\0') contains: |
828 | |
829 | { magic_get, magic_set, magic_len, 0, 0 } |
830 | |
831 | Thus, when an SV is determined to be magical and of type '\0', if a get |
832 | operation is being performed, the routine C<magic_get> is called. All |
833 | the various routines for the various magical types begin with C<magic_>. |
834 | |
835 | The current kinds of Magic Virtual Tables are: |
836 | |
837 | mg_type MGVTBL Type of magicalness |
838 | ------- ------ ------------------- |
839 | \0 vtbl_sv Regexp??? |
840 | A vtbl_amagic Operator Overloading |
841 | a vtbl_amagicelem Operator Overloading |
842 | c 0 Used in Operator Overloading |
843 | B vtbl_bm Boyer-Moore??? |
844 | E vtbl_env %ENV hash |
845 | e vtbl_envelem %ENV hash element |
846 | g vtbl_mglob Regexp /g flag??? |
847 | I vtbl_isa @ISA array |
848 | i vtbl_isaelem @ISA array element |
849 | L 0 (but sets RMAGICAL) Perl Module/Debugger??? |
850 | l vtbl_dbline Debugger? |
851 | P vtbl_pack Tied Array or Hash |
852 | p vtbl_packelem Tied Array or Hash element |
853 | q vtbl_packelem Tied Scalar or Handle |
854 | S vtbl_sig Signal Hash |
855 | s vtbl_sigelem Signal Hash element |
856 | t vtbl_taint Taintedness |
857 | U vtbl_uvar ??? |
858 | v vtbl_vec Vector |
859 | x vtbl_substr Substring??? |
860 | * vtbl_glob GV??? |
861 | # vtbl_arylen Array Length |
862 | . vtbl_pos $. scalar variable |
863 | ~ Reserved for extensions, but multiple extensions may clash |
864 | |
865 | When an upper-case and lower-case letter both exist in the table, then the |
866 | upper-case letter is used to represent some kind of composite type (a list |
867 | or a hash), and the lower-case letter is used to represent an element of |
868 | that composite type. |
869 | |
870 | =head2 Finding Magic |
871 | |
872 | MAGIC* mg_find(SV*, int type); /* Finds the magic pointer of that type */ |
873 | |
874 | This routine returns a pointer to the C<MAGIC> structure stored in the SV. |
875 | If the SV does not have that magical feature, C<NULL> is returned. Also, |
876 | if the SV is not of type SVt_PVMG, Perl may core-dump. |
877 | |
878 | int mg_copy(SV* sv, SV* nsv, char* key, STRLEN klen); |
879 | |
880 | This routine checks to see what types of magic C<sv> has. If the mg_type |
881 | field is an upper-case letter, then the mg_obj is copied to C<nsv>, but |
882 | the mg_type field is changed to be the lower-case letter. |
a0d0e21e |
883 | |
5fb8527f |
884 | =head1 Double-Typed SVs |
a0d0e21e |
885 | |
886 | Scalar variables normally contain only one type of value, an integer, |
887 | double, pointer, or reference. Perl will automatically convert the |
888 | actual scalar data from the stored type into the requested type. |
889 | |
890 | Some scalar variables contain more than one type of scalar data. For |
891 | example, the variable C<$!> contains either the numeric value of C<errno> |
d1b91892 |
892 | or its string equivalent from either C<strerror> or C<sys_errlist[]>. |
a0d0e21e |
893 | |
894 | To force multiple data values into an SV, you must do two things: use the |
895 | C<sv_set*v> routines to add the additional scalar type, then set a flag |
896 | so that Perl will believe it contains more than one type of data. The |
897 | four macros to set the flags are: |
898 | |
899 | SvIOK_on |
900 | SvNOK_on |
901 | SvPOK_on |
902 | SvROK_on |
903 | |
904 | The particular macro you must use depends on which C<sv_set*v> routine |
905 | you called first. This is because every C<sv_set*v> routine turns on |
906 | only the bit for the particular type of data being set, and turns off |
907 | all the rest. |
908 | |
909 | For example, to create a new Perl variable called "dberror" that contains |
910 | both the numeric and descriptive string error values, you could use the |
911 | following code: |
912 | |
913 | extern int dberror; |
914 | extern char *dberror_list; |
915 | |
916 | SV* sv = perl_get_sv("dberror", TRUE); |
917 | sv_setiv(sv, (IV) dberror); |
918 | sv_setpv(sv, dberror_list[dberror]); |
919 | SvIOK_on(sv); |
920 | |
921 | If the order of C<sv_setiv> and C<sv_setpv> had been reversed, then the |
922 | macro C<SvPOK_on> would need to be called instead of C<SvIOK_on>. |
923 | |
924 | =head1 Calling Perl Routines from within C Programs |
925 | |
926 | There are four routines that can be used to call a Perl subroutine from |
927 | within a C program. These four are: |
928 | |
929 | I32 perl_call_sv(SV*, I32); |
930 | I32 perl_call_pv(char*, I32); |
931 | I32 perl_call_method(char*, I32); |
932 | I32 perl_call_argv(char*, I32, register char**); |
933 | |
d1b91892 |
934 | The routine most often used is C<perl_call_sv>. The C<SV*> argument |
935 | contains either the name of the Perl subroutine to be called, or a |
936 | reference to the subroutine. The second argument consists of flags |
937 | that control the context in which the subroutine is called, whether |
938 | or not the subroutine is being passed arguments, how errors should be |
939 | trapped, and how to treat return values. |
a0d0e21e |
940 | |
941 | All four routines return the number of arguments that the subroutine returned |
942 | on the Perl stack. |
943 | |
d1b91892 |
944 | When using any of these routines (except C<perl_call_argv>), the programmer |
945 | must manipulate the Perl stack. These include the following macros and |
946 | functions: |
a0d0e21e |
947 | |
948 | dSP |
949 | PUSHMARK() |
950 | PUTBACK |
951 | SPAGAIN |
952 | ENTER |
953 | SAVETMPS |
954 | FREETMPS |
955 | LEAVE |
956 | XPUSH*() |
cb1a09d0 |
957 | POP*() |
a0d0e21e |
958 | |
959 | For more information, consult L<perlcall>. |
960 | |
961 | =head1 Memory Allocation |
962 | |
d1b91892 |
963 | It is strongly suggested that you use the version of malloc that is distributed |
964 | with Perl. It keeps pools of various sizes of unallocated memory in order to |
965 | more quickly satisfy allocation requests. |
966 | However, on some platforms, it may cause spurious malloc or free errors. |
967 | |
968 | New(x, pointer, number, type); |
969 | Newc(x, pointer, number, type, cast); |
970 | Newz(x, pointer, number, type); |
971 | |
972 | These three macros are used to initially allocate memory. The first argument |
973 | C<x> was a "magic cookie" that was used to keep track of who called the macro, |
974 | to help when debugging memory problems. However, the current code makes no |
975 | use of this feature (Larry has switched to using a run-time memory checker), |
976 | so this argument can be any number. |
977 | |
978 | The second argument C<pointer> will point to the newly allocated memory. |
979 | The third and fourth arguments C<number> and C<type> specify how many of |
980 | the specified type of data structure should be allocated. The argument |
981 | C<type> is passed to C<sizeof>. The final argument to C<Newc>, C<cast>, |
982 | should be used if the C<pointer> argument is different from the C<type> |
983 | argument. |
984 | |
985 | Unlike the C<New> and C<Newc> macros, the C<Newz> macro calls C<memzero> |
986 | to zero out all the newly allocated memory. |
987 | |
988 | Renew(pointer, number, type); |
989 | Renewc(pointer, number, type, cast); |
990 | Safefree(pointer) |
991 | |
992 | These three macros are used to change a memory buffer size or to free a |
993 | piece of memory no longer needed. The arguments to C<Renew> and C<Renewc> |
994 | match those of C<New> and C<Newc> with the exception of not needing the |
995 | "magic cookie" argument. |
996 | |
997 | Move(source, dest, number, type); |
998 | Copy(source, dest, number, type); |
999 | Zero(dest, number, type); |
1000 | |
1001 | These three macros are used to move, copy, or zero out previously allocated |
1002 | memory. The C<source> and C<dest> arguments point to the source and |
1003 | destination starting points. Perl will move, copy, or zero out C<number> |
1004 | instances of the size of the C<type> data structure (using the C<sizeof> |
1005 | function). |
a0d0e21e |
1006 | |
cb1a09d0 |
1007 | =head1 API LISTING |
a0d0e21e |
1008 | |
cb1a09d0 |
1009 | This is a listing of functions, macros, flags, and variables that may be |
1010 | useful to extension writers or that may be found while reading other |
1011 | extensions. |
a0d0e21e |
1012 | |
cb1a09d0 |
1013 | =over 8 |
a0d0e21e |
1014 | |
cb1a09d0 |
1015 | =item AvFILL |
1016 | |
1017 | See C<av_len>. |
1018 | |
1019 | =item av_clear |
1020 | |
1021 | Clears an array, making it empty. |
1022 | |
1023 | void av_clear _((AV* ar)); |
1024 | |
1025 | =item av_extend |
1026 | |
1027 | Pre-extend an array. The C<key> is the index to which the array should be |
1028 | extended. |
1029 | |
1030 | void av_extend _((AV* ar, I32 key)); |
1031 | |
1032 | =item av_fetch |
1033 | |
1034 | Returns the SV at the specified index in the array. The C<key> is the |
1035 | index. If C<lval> is set then the fetch will be part of a store. Check |
1036 | that the return value is non-null before dereferencing it to a C<SV*>. |
1037 | |
1038 | SV** av_fetch _((AV* ar, I32 key, I32 lval)); |
1039 | |
1040 | =item av_len |
1041 | |
1042 | Returns the highest index in the array. Returns -1 if the array is empty. |
1043 | |
1044 | I32 av_len _((AV* ar)); |
1045 | |
1046 | =item av_make |
1047 | |
5fb8527f |
1048 | Creates a new AV and populates it with a list of SVs. The SVs are copied |
1049 | into the array, so they may be freed after the call to av_make. The new AV |
1050 | will have a refcount of 1. |
cb1a09d0 |
1051 | |
1052 | AV* av_make _((I32 size, SV** svp)); |
1053 | |
1054 | =item av_pop |
1055 | |
1056 | Pops an SV off the end of the array. Returns C<&sv_undef> if the array is |
1057 | empty. |
1058 | |
1059 | SV* av_pop _((AV* ar)); |
1060 | |
1061 | =item av_push |
1062 | |
5fb8527f |
1063 | Pushes an SV onto the end of the array. The array will grow automatically |
1064 | to accommodate the addition. |
cb1a09d0 |
1065 | |
1066 | void av_push _((AV* ar, SV* val)); |
1067 | |
1068 | =item av_shift |
1069 | |
1070 | Shifts an SV off the beginning of the array. |
1071 | |
1072 | SV* av_shift _((AV* ar)); |
1073 | |
1074 | =item av_store |
1075 | |
1076 | Stores an SV in an array. The array index is specified as C<key>. The |
1077 | return value will be null if the operation failed, otherwise it can be |
1078 | dereferenced to get the original C<SV*>. |
1079 | |
1080 | SV** av_store _((AV* ar, I32 key, SV* val)); |
1081 | |
1082 | =item av_undef |
1083 | |
1084 | Undefines the array. |
1085 | |
1086 | void av_undef _((AV* ar)); |
1087 | |
1088 | =item av_unshift |
1089 | |
5fb8527f |
1090 | Unshift an SV onto the beginning of the array. The array will grow |
1091 | automatically to accommodate the addition. |
cb1a09d0 |
1092 | |
1093 | void av_unshift _((AV* ar, I32 num)); |
1094 | |
1095 | =item CLASS |
1096 | |
1097 | Variable which is setup by C<xsubpp> to indicate the class name for a C++ XS |
5fb8527f |
1098 | constructor. This is always a C<char*>. See C<THIS> and |
1099 | L<perlxs/"Using XS With C++">. |
cb1a09d0 |
1100 | |
1101 | =item Copy |
1102 | |
1103 | The XSUB-writer's interface to the C C<memcpy> function. The C<s> is the |
1104 | source, C<d> is the destination, C<n> is the number of items, and C<t> is |
1105 | the type. |
1106 | |
1107 | (void) Copy( s, d, n, t ); |
1108 | |
1109 | =item croak |
1110 | |
1111 | This is the XSUB-writer's interface to Perl's C<die> function. Use this |
1112 | function the same way you use the C C<printf> function. See C<warn>. |
1113 | |
1114 | =item CvSTASH |
1115 | |
1116 | Returns the stash of the CV. |
1117 | |
1118 | HV * CvSTASH( SV* sv ) |
1119 | |
1120 | =item DBsingle |
1121 | |
1122 | When Perl is run in debugging mode, with the B<-d> switch, this SV is a |
1123 | boolean which indicates whether subs are being single-stepped. |
5fb8527f |
1124 | Single-stepping is automatically turned on after every step. This is the C |
1125 | variable which corresponds to Perl's $DB::single variable. See C<DBsub>. |
cb1a09d0 |
1126 | |
1127 | =item DBsub |
1128 | |
1129 | When Perl is run in debugging mode, with the B<-d> switch, this GV contains |
5fb8527f |
1130 | the SV which holds the name of the sub being debugged. This is the C |
1131 | variable which corresponds to Perl's $DB::sub variable. See C<DBsingle>. |
cb1a09d0 |
1132 | The sub name can be found by |
1133 | |
1134 | SvPV( GvSV( DBsub ), na ) |
1135 | |
5fb8527f |
1136 | =item DBtrace |
1137 | |
1138 | Trace variable used when Perl is run in debugging mode, with the B<-d> |
1139 | switch. This is the C variable which corresponds to Perl's $DB::trace |
1140 | variable. See C<DBsingle>. |
1141 | |
cb1a09d0 |
1142 | =item dMARK |
1143 | |
5fb8527f |
1144 | Declare a stack marker variable, C<mark>, for the XSUB. See C<MARK> and |
1145 | C<dORIGMARK>. |
cb1a09d0 |
1146 | |
1147 | =item dORIGMARK |
1148 | |
1149 | Saves the original stack mark for the XSUB. See C<ORIGMARK>. |
1150 | |
5fb8527f |
1151 | =item dowarn |
1152 | |
1153 | The C variable which corresponds to Perl's $^W warning variable. |
1154 | |
cb1a09d0 |
1155 | =item dSP |
1156 | |
5fb8527f |
1157 | Declares a stack pointer variable, C<sp>, for the XSUB. See C<SP>. |
cb1a09d0 |
1158 | |
1159 | =item dXSARGS |
1160 | |
1161 | Sets up stack and mark pointers for an XSUB, calling dSP and dMARK. This is |
1162 | usually handled automatically by C<xsubpp>. Declares the C<items> variable |
1163 | to indicate the number of items on the stack. |
1164 | |
5fb8527f |
1165 | =item dXSI32 |
1166 | |
1167 | Sets up the C<ix> variable for an XSUB which has aliases. This is usually |
1168 | handled automatically by C<xsubpp>. |
1169 | |
1170 | =item dXSI32 |
1171 | |
1172 | Sets up the C<ix> variable for an XSUB which has aliases. This is usually |
1173 | handled automatically by C<xsubpp>. |
1174 | |
cb1a09d0 |
1175 | =item ENTER |
1176 | |
1177 | Opening bracket on a callback. See C<LEAVE> and L<perlcall>. |
1178 | |
1179 | ENTER; |
1180 | |
1181 | =item EXTEND |
1182 | |
1183 | Used to extend the argument stack for an XSUB's return values. |
1184 | |
1185 | EXTEND( sp, int x ); |
1186 | |
1187 | =item FREETMPS |
1188 | |
1189 | Closing bracket for temporaries on a callback. See C<SAVETMPS> and |
1190 | L<perlcall>. |
1191 | |
1192 | FREETMPS; |
1193 | |
1194 | =item G_ARRAY |
1195 | |
1196 | Used to indicate array context. See C<GIMME> and L<perlcall>. |
1197 | |
1198 | =item G_DISCARD |
1199 | |
1200 | Indicates that arguments returned from a callback should be discarded. See |
1201 | L<perlcall>. |
1202 | |
1203 | =item G_EVAL |
1204 | |
1205 | Used to force a Perl C<eval> wrapper around a callback. See L<perlcall>. |
1206 | |
1207 | =item GIMME |
1208 | |
1209 | The XSUB-writer's equivalent to Perl's C<wantarray>. Returns C<G_SCALAR> or |
1210 | C<G_ARRAY> for scalar or array context. |
1211 | |
1212 | =item G_NOARGS |
1213 | |
1214 | Indicates that no arguments are being sent to a callback. See L<perlcall>. |
1215 | |
1216 | =item G_SCALAR |
1217 | |
1218 | Used to indicate scalar context. See C<GIMME> and L<perlcall>. |
1219 | |
1220 | =item gv_stashpv |
1221 | |
1222 | Returns a pointer to the stash for a specified package. If C<create> is set |
1223 | then the package will be created if it does not already exist. If C<create> |
1224 | is not set and the package does not exist then NULL is returned. |
1225 | |
1226 | HV* gv_stashpv _((char* name, I32 create)); |
1227 | |
1228 | =item gv_stashsv |
1229 | |
1230 | Returns a pointer to the stash for a specified package. See C<gv_stashpv>. |
1231 | |
1232 | HV* gv_stashsv _((SV* sv, I32 create)); |
1233 | |
1234 | =item GvSV |
1235 | |
1236 | Return the SV from the GV. |
1237 | |
1238 | =item he_free |
1239 | |
1240 | Releases a hash entry from an iterator. See C<hv_iternext>. |
1241 | |
1242 | =item hv_clear |
1243 | |
1244 | Clears a hash, making it empty. |
1245 | |
1246 | void hv_clear _((HV* tb)); |
1247 | |
1248 | =item hv_delete |
1249 | |
1250 | Deletes a key/value pair in the hash. The value SV is removed from the hash |
5fb8527f |
1251 | and returned to the caller. The C<klen> is the length of the key. The |
cb1a09d0 |
1252 | C<flags> value will normally be zero; if set to G_DISCARD then null will be |
1253 | returned. |
1254 | |
1255 | SV* hv_delete _((HV* tb, char* key, U32 klen, I32 flags)); |
1256 | |
1257 | =item hv_exists |
1258 | |
1259 | Returns a boolean indicating whether the specified hash key exists. The |
5fb8527f |
1260 | C<klen> is the length of the key. |
cb1a09d0 |
1261 | |
1262 | bool hv_exists _((HV* tb, char* key, U32 klen)); |
1263 | |
1264 | =item hv_fetch |
1265 | |
1266 | Returns the SV which corresponds to the specified key in the hash. The |
5fb8527f |
1267 | C<klen> is the length of the key. If C<lval> is set then the fetch will be |
cb1a09d0 |
1268 | part of a store. Check that the return value is non-null before |
1269 | dereferencing it to a C<SV*>. |
1270 | |
1271 | SV** hv_fetch _((HV* tb, char* key, U32 klen, I32 lval)); |
1272 | |
1273 | =item hv_iterinit |
1274 | |
1275 | Prepares a starting point to traverse a hash table. |
1276 | |
1277 | I32 hv_iterinit _((HV* tb)); |
1278 | |
1279 | =item hv_iterkey |
1280 | |
1281 | Returns the key from the current position of the hash iterator. See |
1282 | C<hv_iterinit>. |
1283 | |
1284 | char* hv_iterkey _((HE* entry, I32* retlen)); |
1285 | |
1286 | =item hv_iternext |
1287 | |
1288 | Returns entries from a hash iterator. See C<hv_iterinit>. |
1289 | |
1290 | HE* hv_iternext _((HV* tb)); |
1291 | |
1292 | =item hv_iternextsv |
1293 | |
1294 | Performs an C<hv_iternext>, C<hv_iterkey>, and C<hv_iterval> in one |
1295 | operation. |
1296 | |
1297 | SV * hv_iternextsv _((HV* hv, char** key, I32* retlen)); |
1298 | |
1299 | =item hv_iterval |
1300 | |
1301 | Returns the value from the current position of the hash iterator. See |
1302 | C<hv_iterkey>. |
1303 | |
1304 | SV* hv_iterval _((HV* tb, HE* entry)); |
1305 | |
1306 | =item hv_magic |
1307 | |
1308 | Adds magic to a hash. See C<sv_magic>. |
1309 | |
1310 | void hv_magic _((HV* hv, GV* gv, int how)); |
1311 | |
1312 | =item HvNAME |
1313 | |
1314 | Returns the package name of a stash. See C<SvSTASH>, C<CvSTASH>. |
1315 | |
1316 | char *HvNAME (HV* stash) |
1317 | |
1318 | =item hv_store |
1319 | |
1320 | Stores an SV in a hash. The hash key is specified as C<key> and C<klen> is |
1321 | the length of the key. The C<hash> parameter is the pre-computed hash |
1322 | value; if it is zero then Perl will compute it. The return value will be |
1323 | null if the operation failed, otherwise it can be dereferenced to get the |
1324 | original C<SV*>. |
1325 | |
1326 | SV** hv_store _((HV* tb, char* key, U32 klen, SV* val, U32 hash)); |
1327 | |
1328 | =item hv_undef |
1329 | |
1330 | Undefines the hash. |
1331 | |
1332 | void hv_undef _((HV* tb)); |
1333 | |
1334 | =item isALNUM |
1335 | |
1336 | Returns a boolean indicating whether the C C<char> is an ascii alphanumeric |
5fb8527f |
1337 | character. |
cb1a09d0 |
1338 | |
1339 | int isALNUM (char c) |
1340 | |
1341 | =item isALPHA |
1342 | |
5fb8527f |
1343 | Returns a boolean indicating whether the C C<char> is an ascii alphabetic |
cb1a09d0 |
1344 | character. |
1345 | |
1346 | int isALPHA (char c) |
1347 | |
1348 | =item isDIGIT |
1349 | |
1350 | Returns a boolean indicating whether the C C<char> is an ascii digit. |
1351 | |
1352 | int isDIGIT (char c) |
1353 | |
1354 | =item isLOWER |
1355 | |
1356 | Returns a boolean indicating whether the C C<char> is a lowercase character. |
1357 | |
1358 | int isLOWER (char c) |
1359 | |
1360 | =item isSPACE |
1361 | |
1362 | Returns a boolean indicating whether the C C<char> is whitespace. |
1363 | |
1364 | int isSPACE (char c) |
1365 | |
1366 | =item isUPPER |
1367 | |
1368 | Returns a boolean indicating whether the C C<char> is an uppercase character. |
1369 | |
1370 | int isUPPER (char c) |
1371 | |
1372 | =item items |
1373 | |
1374 | Variable which is setup by C<xsubpp> to indicate the number of items on the |
5fb8527f |
1375 | stack. See L<perlxs/"Variable-length Parameter Lists">. |
1376 | |
1377 | =item ix |
1378 | |
1379 | Variable which is setup by C<xsubpp> to indicate which of an XSUB's aliases |
1380 | was used to invoke it. See L<perlxs/"The ALIAS: Keyword">. |
cb1a09d0 |
1381 | |
1382 | =item LEAVE |
1383 | |
1384 | Closing bracket on a callback. See C<ENTER> and L<perlcall>. |
1385 | |
1386 | LEAVE; |
1387 | |
1388 | =item MARK |
1389 | |
5fb8527f |
1390 | Stack marker variable for the XSUB. See C<dMARK>. |
cb1a09d0 |
1391 | |
1392 | =item mg_clear |
1393 | |
1394 | Clear something magical that the SV represents. See C<sv_magic>. |
1395 | |
1396 | int mg_clear _((SV* sv)); |
1397 | |
1398 | =item mg_copy |
1399 | |
1400 | Copies the magic from one SV to another. See C<sv_magic>. |
1401 | |
1402 | int mg_copy _((SV *, SV *, char *, STRLEN)); |
1403 | |
1404 | =item mg_find |
1405 | |
1406 | Finds the magic pointer for type matching the SV. See C<sv_magic>. |
1407 | |
1408 | MAGIC* mg_find _((SV* sv, int type)); |
1409 | |
1410 | =item mg_free |
1411 | |
1412 | Free any magic storage used by the SV. See C<sv_magic>. |
1413 | |
1414 | int mg_free _((SV* sv)); |
1415 | |
1416 | =item mg_get |
1417 | |
1418 | Do magic after a value is retrieved from the SV. See C<sv_magic>. |
1419 | |
1420 | int mg_get _((SV* sv)); |
1421 | |
1422 | =item mg_len |
1423 | |
1424 | Report on the SV's length. See C<sv_magic>. |
1425 | |
1426 | U32 mg_len _((SV* sv)); |
1427 | |
1428 | =item mg_magical |
1429 | |
1430 | Turns on the magical status of an SV. See C<sv_magic>. |
1431 | |
1432 | void mg_magical _((SV* sv)); |
1433 | |
1434 | =item mg_set |
1435 | |
1436 | Do magic after a value is assigned to the SV. See C<sv_magic>. |
1437 | |
1438 | int mg_set _((SV* sv)); |
1439 | |
1440 | =item Move |
1441 | |
1442 | The XSUB-writer's interface to the C C<memmove> function. The C<s> is the |
1443 | source, C<d> is the destination, C<n> is the number of items, and C<t> is |
1444 | the type. |
1445 | |
1446 | (void) Move( s, d, n, t ); |
1447 | |
1448 | =item na |
1449 | |
1450 | A variable which may be used with C<SvPV> to tell Perl to calculate the |
1451 | string length. |
1452 | |
1453 | =item New |
1454 | |
1455 | The XSUB-writer's interface to the C C<malloc> function. |
1456 | |
1457 | void * New( x, void *ptr, int size, type ) |
1458 | |
1459 | =item Newc |
1460 | |
1461 | The XSUB-writer's interface to the C C<malloc> function, with cast. |
1462 | |
1463 | void * Newc( x, void *ptr, int size, type, cast ) |
1464 | |
1465 | =item Newz |
1466 | |
1467 | The XSUB-writer's interface to the C C<malloc> function. The allocated |
1468 | memory is zeroed with C<memzero>. |
1469 | |
1470 | void * Newz( x, void *ptr, int size, type ) |
1471 | |
1472 | =item newAV |
1473 | |
1474 | Creates a new AV. The refcount is set to 1. |
1475 | |
1476 | AV* newAV _((void)); |
1477 | |
1478 | =item newHV |
1479 | |
1480 | Creates a new HV. The refcount is set to 1. |
1481 | |
1482 | HV* newHV _((void)); |
1483 | |
1484 | =item newRV |
1485 | |
1486 | Creates an RV wrapper for an SV. The refcount for the original SV is |
1487 | incremented. |
1488 | |
1489 | SV* newRV _((SV* ref)); |
1490 | |
1491 | =item newSV |
1492 | |
1493 | Creates a new SV. The C<len> parameter indicates the number of bytes of |
1494 | pre-allocated string space the SV should have. The refcount for the new SV |
1495 | is set to 1. |
1496 | |
1497 | SV* newSV _((STRLEN len)); |
1498 | |
1499 | =item newSViv |
1500 | |
1501 | Creates a new SV and copies an integer into it. The refcount for the SV is |
1502 | set to 1. |
1503 | |
1504 | SV* newSViv _((IV i)); |
1505 | |
1506 | =item newSVnv |
1507 | |
1508 | Creates a new SV and copies a double into it. The refcount for the SV is |
1509 | set to 1. |
1510 | |
1511 | SV* newSVnv _((NV i)); |
1512 | |
1513 | =item newSVpv |
1514 | |
1515 | Creates a new SV and copies a string into it. The refcount for the SV is |
1516 | set to 1. If C<len> is zero then Perl will compute the length. |
1517 | |
1518 | SV* newSVpv _((char* s, STRLEN len)); |
1519 | |
1520 | =item newSVrv |
1521 | |
1522 | Creates a new SV for the RV, C<rv>, to point to. If C<rv> is not an RV then |
5fb8527f |
1523 | it will be upgraded to one. If C<classname> is non-null then the new SV will |
cb1a09d0 |
1524 | be blessed in the specified package. The new SV is returned and its |
1525 | refcount is 1. |
1526 | |
1527 | SV* newSVrv _((SV* rv, char* classname)); |
1528 | |
1529 | =item newSVsv |
1530 | |
5fb8527f |
1531 | Creates a new SV which is an exact duplicate of the original SV. |
cb1a09d0 |
1532 | |
1533 | SV* newSVsv _((SV* old)); |
1534 | |
1535 | =item newXS |
1536 | |
1537 | Used by C<xsubpp> to hook up XSUBs as Perl subs. |
1538 | |
1539 | =item newXSproto |
1540 | |
1541 | Used by C<xsubpp> to hook up XSUBs as Perl subs. Adds Perl prototypes to |
1542 | the subs. |
1543 | |
1544 | =item Nullav |
1545 | |
1546 | Null AV pointer. |
1547 | |
1548 | =item Nullch |
1549 | |
1550 | Null character pointer. |
1551 | |
1552 | =item Nullcv |
1553 | |
1554 | Null CV pointer. |
1555 | |
1556 | =item Nullhv |
1557 | |
1558 | Null HV pointer. |
1559 | |
1560 | =item Nullsv |
1561 | |
1562 | Null SV pointer. |
1563 | |
1564 | =item ORIGMARK |
1565 | |
1566 | The original stack mark for the XSUB. See C<dORIGMARK>. |
1567 | |
1568 | =item perl_alloc |
1569 | |
1570 | Allocates a new Perl interpreter. See L<perlembed>. |
1571 | |
1572 | =item perl_call_argv |
1573 | |
1574 | Performs a callback to the specified Perl sub. See L<perlcall>. |
1575 | |
1576 | I32 perl_call_argv _((char* subname, I32 flags, char** argv)); |
1577 | |
1578 | =item perl_call_method |
1579 | |
1580 | Performs a callback to the specified Perl method. The blessed object must |
1581 | be on the stack. See L<perlcall>. |
1582 | |
1583 | I32 perl_call_method _((char* methname, I32 flags)); |
1584 | |
1585 | =item perl_call_pv |
1586 | |
1587 | Performs a callback to the specified Perl sub. See L<perlcall>. |
1588 | |
1589 | I32 perl_call_pv _((char* subname, I32 flags)); |
1590 | |
1591 | =item perl_call_sv |
1592 | |
1593 | Performs a callback to the Perl sub whose name is in the SV. See |
1594 | L<perlcall>. |
1595 | |
1596 | I32 perl_call_sv _((SV* sv, I32 flags)); |
1597 | |
1598 | =item perl_construct |
1599 | |
1600 | Initializes a new Perl interpreter. See L<perlembed>. |
1601 | |
1602 | =item perl_destruct |
1603 | |
1604 | Shuts down a Perl interpreter. See L<perlembed>. |
1605 | |
1606 | =item perl_eval_sv |
1607 | |
1608 | Tells Perl to C<eval> the string in the SV. |
1609 | |
1610 | I32 perl_eval_sv _((SV* sv, I32 flags)); |
1611 | |
1612 | =item perl_free |
1613 | |
1614 | Releases a Perl interpreter. See L<perlembed>. |
1615 | |
1616 | =item perl_get_av |
1617 | |
1618 | Returns the AV of the specified Perl array. If C<create> is set and the |
1619 | Perl variable does not exist then it will be created. If C<create> is not |
1620 | set and the variable does not exist then null is returned. |
1621 | |
1622 | AV* perl_get_av _((char* name, I32 create)); |
1623 | |
1624 | =item perl_get_cv |
1625 | |
1626 | Returns the CV of the specified Perl sub. If C<create> is set and the Perl |
1627 | variable does not exist then it will be created. If C<create> is not |
1628 | set and the variable does not exist then null is returned. |
1629 | |
1630 | CV* perl_get_cv _((char* name, I32 create)); |
1631 | |
1632 | =item perl_get_hv |
1633 | |
1634 | Returns the HV of the specified Perl hash. If C<create> is set and the Perl |
1635 | variable does not exist then it will be created. If C<create> is not |
1636 | set and the variable does not exist then null is returned. |
1637 | |
1638 | HV* perl_get_hv _((char* name, I32 create)); |
1639 | |
1640 | =item perl_get_sv |
1641 | |
1642 | Returns the SV of the specified Perl scalar. If C<create> is set and the |
1643 | Perl variable does not exist then it will be created. If C<create> is not |
1644 | set and the variable does not exist then null is returned. |
1645 | |
1646 | SV* perl_get_sv _((char* name, I32 create)); |
1647 | |
1648 | =item perl_parse |
1649 | |
1650 | Tells a Perl interpreter to parse a Perl script. See L<perlembed>. |
1651 | |
1652 | =item perl_require_pv |
1653 | |
1654 | Tells Perl to C<require> a module. |
1655 | |
1656 | void perl_require_pv _((char* pv)); |
1657 | |
1658 | =item perl_run |
1659 | |
1660 | Tells a Perl interpreter to run. See L<perlembed>. |
1661 | |
1662 | =item POPi |
1663 | |
1664 | Pops an integer off the stack. |
1665 | |
1666 | int POPi(); |
1667 | |
1668 | =item POPl |
1669 | |
1670 | Pops a long off the stack. |
1671 | |
1672 | long POPl(); |
1673 | |
1674 | =item POPp |
1675 | |
1676 | Pops a string off the stack. |
1677 | |
1678 | char * POPp(); |
1679 | |
1680 | =item POPn |
1681 | |
1682 | Pops a double off the stack. |
1683 | |
1684 | double POPn(); |
1685 | |
1686 | =item POPs |
1687 | |
1688 | Pops an SV off the stack. |
1689 | |
1690 | SV* POPs(); |
1691 | |
1692 | =item PUSHMARK |
1693 | |
1694 | Opening bracket for arguments on a callback. See C<PUTBACK> and L<perlcall>. |
1695 | |
1696 | PUSHMARK(p) |
1697 | |
1698 | =item PUSHi |
1699 | |
1700 | Push an integer onto the stack. The stack must have room for this element. |
1701 | See C<XPUSHi>. |
1702 | |
1703 | PUSHi(int d) |
1704 | |
1705 | =item PUSHn |
1706 | |
1707 | Push a double onto the stack. The stack must have room for this element. |
1708 | See C<XPUSHn>. |
1709 | |
1710 | PUSHn(double d) |
1711 | |
1712 | =item PUSHp |
1713 | |
1714 | Push a string onto the stack. The stack must have room for this element. |
1715 | The C<len> indicates the length of the string. See C<XPUSHp>. |
1716 | |
1717 | PUSHp(char *c, int len ) |
1718 | |
1719 | =item PUSHs |
1720 | |
1721 | Push an SV onto the stack. The stack must have room for this element. See |
1722 | C<XPUSHs>. |
1723 | |
1724 | PUSHs(sv) |
1725 | |
1726 | =item PUTBACK |
1727 | |
1728 | Closing bracket for XSUB arguments. This is usually handled by C<xsubpp>. |
1729 | See C<PUSHMARK> and L<perlcall> for other uses. |
1730 | |
1731 | PUTBACK; |
1732 | |
1733 | =item Renew |
1734 | |
1735 | The XSUB-writer's interface to the C C<realloc> function. |
1736 | |
1737 | void * Renew( void *ptr, int size, type ) |
1738 | |
1739 | =item Renewc |
1740 | |
1741 | The XSUB-writer's interface to the C C<realloc> function, with cast. |
1742 | |
1743 | void * Renewc( void *ptr, int size, type, cast ) |
1744 | |
1745 | =item RETVAL |
1746 | |
1747 | Variable which is setup by C<xsubpp> to hold the return value for an XSUB. |
5fb8527f |
1748 | This is always the proper type for the XSUB. |
1749 | See L<perlxs/"The RETVAL Variable">. |
cb1a09d0 |
1750 | |
1751 | =item safefree |
1752 | |
1753 | The XSUB-writer's interface to the C C<free> function. |
1754 | |
1755 | =item safemalloc |
1756 | |
1757 | The XSUB-writer's interface to the C C<malloc> function. |
1758 | |
1759 | =item saferealloc |
1760 | |
1761 | The XSUB-writer's interface to the C C<realloc> function. |
1762 | |
1763 | =item savepv |
1764 | |
1765 | Copy a string to a safe spot. This does not use an SV. |
1766 | |
1767 | char* savepv _((char* sv)); |
1768 | |
1769 | =item savepvn |
1770 | |
1771 | Copy a string to a safe spot. The C<len> indicates number of bytes to |
1772 | copy. This does not use an SV. |
1773 | |
1774 | char* savepvn _((char* sv, I32 len)); |
1775 | |
1776 | =item SAVETMPS |
1777 | |
1778 | Opening bracket for temporaries on a callback. See C<FREETMPS> and |
1779 | L<perlcall>. |
1780 | |
1781 | SAVETMPS; |
1782 | |
1783 | =item SP |
1784 | |
1785 | Stack pointer. This is usually handled by C<xsubpp>. See C<dSP> and |
1786 | C<SPAGAIN>. |
1787 | |
1788 | =item SPAGAIN |
1789 | |
1790 | Refetch the stack pointer. Used after a callback. See L<perlcall>. |
1791 | |
1792 | SPAGAIN; |
1793 | |
1794 | =item ST |
1795 | |
1796 | Used to access elements on the XSUB's stack. |
1797 | |
1798 | SV* ST(int x) |
1799 | |
1800 | =item strEQ |
1801 | |
1802 | Test two strings to see if they are equal. Returns true or false. |
1803 | |
1804 | int strEQ( char *s1, char *s2 ) |
1805 | |
1806 | =item strGE |
1807 | |
1808 | Test two strings to see if the first, C<s1>, is greater than or equal to the |
1809 | second, C<s2>. Returns true or false. |
1810 | |
1811 | int strGE( char *s1, char *s2 ) |
1812 | |
1813 | =item strGT |
1814 | |
1815 | Test two strings to see if the first, C<s1>, is greater than the second, |
1816 | C<s2>. Returns true or false. |
1817 | |
1818 | int strGT( char *s1, char *s2 ) |
1819 | |
1820 | =item strLE |
1821 | |
1822 | Test two strings to see if the first, C<s1>, is less than or equal to the |
1823 | second, C<s2>. Returns true or false. |
1824 | |
1825 | int strLE( char *s1, char *s2 ) |
1826 | |
1827 | =item strLT |
1828 | |
1829 | Test two strings to see if the first, C<s1>, is less than the second, |
1830 | C<s2>. Returns true or false. |
1831 | |
1832 | int strLT( char *s1, char *s2 ) |
1833 | |
1834 | =item strNE |
1835 | |
1836 | Test two strings to see if they are different. Returns true or false. |
1837 | |
1838 | int strNE( char *s1, char *s2 ) |
1839 | |
1840 | =item strnEQ |
1841 | |
1842 | Test two strings to see if they are equal. The C<len> parameter indicates |
1843 | the number of bytes to compare. Returns true or false. |
1844 | |
1845 | int strnEQ( char *s1, char *s2 ) |
1846 | |
1847 | =item strnNE |
1848 | |
1849 | Test two strings to see if they are different. The C<len> parameter |
1850 | indicates the number of bytes to compare. Returns true or false. |
1851 | |
1852 | int strnNE( char *s1, char *s2, int len ) |
1853 | |
1854 | =item sv_2mortal |
1855 | |
1856 | Marks an SV as mortal. The SV will be destroyed when the current context |
1857 | ends. |
1858 | |
1859 | SV* sv_2mortal _((SV* sv)); |
1860 | |
1861 | =item sv_bless |
1862 | |
1863 | Blesses an SV into a specified package. The SV must be an RV. The package |
1864 | must be designated by its stash (see C<gv_stashpv()>). The refcount of the |
1865 | SV is unaffected. |
1866 | |
1867 | SV* sv_bless _((SV* sv, HV* stash)); |
1868 | |
1869 | =item sv_catpv |
1870 | |
1871 | Concatenates the string onto the end of the string which is in the SV. |
1872 | |
1873 | void sv_catpv _((SV* sv, char* ptr)); |
1874 | |
1875 | =item sv_catpvn |
1876 | |
1877 | Concatenates the string onto the end of the string which is in the SV. The |
1878 | C<len> indicates number of bytes to copy. |
1879 | |
1880 | void sv_catpvn _((SV* sv, char* ptr, STRLEN len)); |
1881 | |
1882 | =item sv_catsv |
1883 | |
5fb8527f |
1884 | Concatenates the string from SV C<ssv> onto the end of the string in SV |
cb1a09d0 |
1885 | C<dsv>. |
1886 | |
1887 | void sv_catsv _((SV* dsv, SV* ssv)); |
1888 | |
5fb8527f |
1889 | =item sv_cmp |
1890 | |
1891 | Compares the strings in two SVs. Returns -1, 0, or 1 indicating whether the |
1892 | string in C<sv1> is less than, equal to, or greater than the string in |
1893 | C<sv2>. |
1894 | |
1895 | I32 sv_cmp _((SV* sv1, SV* sv2)); |
1896 | |
1897 | =item sv_cmp |
1898 | |
1899 | Compares the strings in two SVs. Returns -1, 0, or 1 indicating whether the |
1900 | string in C<sv1> is less than, equal to, or greater than the string in |
1901 | C<sv2>. |
1902 | |
1903 | I32 sv_cmp _((SV* sv1, SV* sv2)); |
1904 | |
cb1a09d0 |
1905 | =item SvCUR |
1906 | |
1907 | Returns the length of the string which is in the SV. See C<SvLEN>. |
1908 | |
1909 | int SvCUR (SV* sv) |
1910 | |
1911 | =item SvCUR_set |
1912 | |
1913 | Set the length of the string which is in the SV. See C<SvCUR>. |
1914 | |
1915 | SvCUR_set (SV* sv, int val ) |
1916 | |
5fb8527f |
1917 | =item sv_dec |
1918 | |
1919 | Autodecrement of the value in the SV. |
1920 | |
1921 | void sv_dec _((SV* sv)); |
1922 | |
1923 | =item sv_dec |
1924 | |
1925 | Autodecrement of the value in the SV. |
1926 | |
1927 | void sv_dec _((SV* sv)); |
1928 | |
cb1a09d0 |
1929 | =item SvEND |
1930 | |
1931 | Returns a pointer to the last character in the string which is in the SV. |
1932 | See C<SvCUR>. Access the character as |
1933 | |
1934 | *SvEND(sv) |
1935 | |
5fb8527f |
1936 | =item sv_eq |
1937 | |
1938 | Returns a boolean indicating whether the strings in the two SVs are |
1939 | identical. |
1940 | |
1941 | I32 sv_eq _((SV* sv1, SV* sv2)); |
1942 | |
cb1a09d0 |
1943 | =item SvGROW |
1944 | |
5fb8527f |
1945 | Expands the character buffer in the SV. Calls C<sv_grow> to perform the |
1946 | expansion if necessary. Returns a pointer to the character buffer. |
cb1a09d0 |
1947 | |
1948 | char * SvGROW( SV* sv, int len ) |
1949 | |
5fb8527f |
1950 | =item sv_grow |
1951 | |
1952 | Expands the character buffer in the SV. This will use C<sv_unref> and will |
1953 | upgrade the SV to C<SVt_PV>. Returns a pointer to the character buffer. |
1954 | Use C<SvGROW>. |
1955 | |
1956 | =item sv_inc |
1957 | |
1958 | Autoincrement of the value in the SV. |
1959 | |
1960 | void sv_inc _((SV* sv)); |
1961 | |
cb1a09d0 |
1962 | =item SvIOK |
1963 | |
1964 | Returns a boolean indicating whether the SV contains an integer. |
1965 | |
1966 | int SvIOK (SV* SV) |
1967 | |
1968 | =item SvIOK_off |
1969 | |
1970 | Unsets the IV status of an SV. |
1971 | |
1972 | SvIOK_off (SV* sv) |
1973 | |
1974 | =item SvIOK_on |
1975 | |
1976 | Tells an SV that it is an integer. |
1977 | |
1978 | SvIOK_on (SV* sv) |
1979 | |
5fb8527f |
1980 | =item SvIOK_only |
1981 | |
1982 | Tells an SV that it is an integer and disables all other OK bits. |
1983 | |
1984 | SvIOK_on (SV* sv) |
1985 | |
1986 | =item SvIOK_only |
1987 | |
1988 | Tells an SV that it is an integer and disables all other OK bits. |
1989 | |
1990 | SvIOK_on (SV* sv) |
1991 | |
cb1a09d0 |
1992 | =item SvIOKp |
1993 | |
1994 | Returns a boolean indicating whether the SV contains an integer. Checks the |
1995 | B<private> setting. Use C<SvIOK>. |
1996 | |
1997 | int SvIOKp (SV* SV) |
1998 | |
1999 | =item sv_isa |
2000 | |
2001 | Returns a boolean indicating whether the SV is blessed into the specified |
2002 | class. This does not know how to check for subtype, so it doesn't work in |
2003 | an inheritance relationship. |
2004 | |
2005 | int sv_isa _((SV* sv, char* name)); |
2006 | |
2007 | =item SvIV |
2008 | |
2009 | Returns the integer which is in the SV. |
2010 | |
2011 | int SvIV (SV* sv) |
2012 | |
2013 | =item sv_isobject |
2014 | |
2015 | Returns a boolean indicating whether the SV is an RV pointing to a blessed |
2016 | object. If the SV is not an RV, or if the object is not blessed, then this |
2017 | will return false. |
2018 | |
2019 | int sv_isobject _((SV* sv)); |
2020 | |
2021 | =item SvIVX |
2022 | |
2023 | Returns the integer which is stored in the SV. |
2024 | |
2025 | int SvIVX (SV* sv); |
2026 | |
2027 | =item SvLEN |
2028 | |
2029 | Returns the size of the string buffer in the SV. See C<SvCUR>. |
2030 | |
2031 | int SvLEN (SV* sv) |
2032 | |
5fb8527f |
2033 | =item sv_len |
2034 | |
2035 | Returns the length of the string in the SV. Use C<SvCUR>. |
2036 | |
2037 | STRLEN sv_len _((SV* sv)); |
2038 | |
2039 | =item sv_len |
2040 | |
2041 | Returns the length of the string in the SV. Use C<SvCUR>. |
2042 | |
2043 | STRLEN sv_len _((SV* sv)); |
2044 | |
cb1a09d0 |
2045 | =item sv_magic |
2046 | |
2047 | Adds magic to an SV. |
2048 | |
2049 | void sv_magic _((SV* sv, SV* obj, int how, char* name, I32 namlen)); |
2050 | |
2051 | =item sv_mortalcopy |
2052 | |
2053 | Creates a new SV which is a copy of the original SV. The new SV is marked |
2054 | as mortal. |
2055 | |
2056 | SV* sv_mortalcopy _((SV* oldsv)); |
2057 | |
2058 | =item SvOK |
2059 | |
2060 | Returns a boolean indicating whether the value is an SV. |
2061 | |
2062 | int SvOK (SV* sv) |
2063 | |
2064 | =item sv_newmortal |
2065 | |
2066 | Creates a new SV which is mortal. The refcount of the SV is set to 1. |
2067 | |
2068 | SV* sv_newmortal _((void)); |
2069 | |
2070 | =item sv_no |
2071 | |
2072 | This is the C<false> SV. See C<sv_yes>. Always refer to this as C<&sv_no>. |
2073 | |
2074 | =item SvNIOK |
2075 | |
2076 | Returns a boolean indicating whether the SV contains a number, integer or |
2077 | double. |
2078 | |
2079 | int SvNIOK (SV* SV) |
2080 | |
2081 | =item SvNIOK_off |
2082 | |
2083 | Unsets the NV/IV status of an SV. |
2084 | |
2085 | SvNIOK_off (SV* sv) |
2086 | |
2087 | =item SvNIOKp |
2088 | |
2089 | Returns a boolean indicating whether the SV contains a number, integer or |
2090 | double. Checks the B<private> setting. Use C<SvNIOK>. |
2091 | |
2092 | int SvNIOKp (SV* SV) |
2093 | |
2094 | =item SvNOK |
2095 | |
2096 | Returns a boolean indicating whether the SV contains a double. |
2097 | |
2098 | int SvNOK (SV* SV) |
2099 | |
2100 | =item SvNOK_off |
2101 | |
2102 | Unsets the NV status of an SV. |
2103 | |
2104 | SvNOK_off (SV* sv) |
2105 | |
2106 | =item SvNOK_on |
2107 | |
2108 | Tells an SV that it is a double. |
2109 | |
2110 | SvNOK_on (SV* sv) |
2111 | |
5fb8527f |
2112 | =item SvNOK_only |
2113 | |
2114 | Tells an SV that it is a double and disables all other OK bits. |
2115 | |
2116 | SvNOK_on (SV* sv) |
2117 | |
2118 | =item SvNOK_only |
2119 | |
2120 | Tells an SV that it is a double and disables all other OK bits. |
2121 | |
2122 | SvNOK_on (SV* sv) |
2123 | |
cb1a09d0 |
2124 | =item SvNOKp |
2125 | |
2126 | Returns a boolean indicating whether the SV contains a double. Checks the |
2127 | B<private> setting. Use C<SvNOK>. |
2128 | |
2129 | int SvNOKp (SV* SV) |
2130 | |
2131 | =item SvNV |
2132 | |
2133 | Returns the double which is stored in the SV. |
2134 | |
2135 | double SvNV (SV* sv); |
2136 | |
2137 | =item SvNVX |
2138 | |
2139 | Returns the double which is stored in the SV. |
2140 | |
2141 | double SvNVX (SV* sv); |
2142 | |
2143 | =item SvPOK |
2144 | |
2145 | Returns a boolean indicating whether the SV contains a character string. |
2146 | |
2147 | int SvPOK (SV* SV) |
2148 | |
2149 | =item SvPOK_off |
2150 | |
2151 | Unsets the PV status of an SV. |
2152 | |
2153 | SvPOK_off (SV* sv) |
2154 | |
2155 | =item SvPOK_on |
2156 | |
2157 | Tells an SV that it is a string. |
2158 | |
2159 | SvPOK_on (SV* sv) |
2160 | |
5fb8527f |
2161 | =item SvPOK_only |
2162 | |
2163 | Tells an SV that it is a string and disables all other OK bits. |
2164 | |
2165 | SvPOK_on (SV* sv) |
2166 | |
2167 | =item SvPOK_only |
2168 | |
2169 | Tells an SV that it is a string and disables all other OK bits. |
2170 | |
2171 | SvPOK_on (SV* sv) |
2172 | |
cb1a09d0 |
2173 | =item SvPOKp |
2174 | |
2175 | Returns a boolean indicating whether the SV contains a character string. |
2176 | Checks the B<private> setting. Use C<SvPOK>. |
2177 | |
2178 | int SvPOKp (SV* SV) |
2179 | |
2180 | =item SvPV |
2181 | |
2182 | Returns a pointer to the string in the SV, or a stringified form of the SV |
2183 | if the SV does not contain a string. If C<len> is C<na> then Perl will |
2184 | handle the length on its own. |
2185 | |
2186 | char * SvPV (SV* sv, int len ) |
2187 | |
2188 | =item SvPVX |
2189 | |
2190 | Returns a pointer to the string in the SV. The SV must contain a string. |
2191 | |
2192 | char * SvPVX (SV* sv) |
2193 | |
2194 | =item SvREFCNT |
2195 | |
2196 | Returns the value of the object's refcount. |
2197 | |
2198 | int SvREFCNT (SV* sv); |
2199 | |
2200 | =item SvREFCNT_dec |
2201 | |
2202 | Decrements the refcount of the given SV. |
2203 | |
2204 | void SvREFCNT_dec (SV* sv) |
2205 | |
2206 | =item SvREFCNT_inc |
2207 | |
2208 | Increments the refcount of the given SV. |
2209 | |
2210 | void SvREFCNT_inc (SV* sv) |
2211 | |
2212 | =item SvROK |
2213 | |
2214 | Tests if the SV is an RV. |
2215 | |
2216 | int SvROK (SV* sv) |
2217 | |
2218 | =item SvROK_off |
2219 | |
2220 | Unsets the RV status of an SV. |
2221 | |
2222 | SvROK_off (SV* sv) |
2223 | |
2224 | =item SvROK_on |
2225 | |
2226 | Tells an SV that it is an RV. |
2227 | |
2228 | SvROK_on (SV* sv) |
2229 | |
2230 | =item SvRV |
2231 | |
2232 | Dereferences an RV to return the SV. |
2233 | |
2234 | SV* SvRV (SV* sv); |
2235 | |
2236 | =item sv_setiv |
2237 | |
2238 | Copies an integer into the given SV. |
2239 | |
2240 | void sv_setiv _((SV* sv, IV num)); |
2241 | |
2242 | =item sv_setnv |
2243 | |
2244 | Copies a double into the given SV. |
2245 | |
2246 | void sv_setnv _((SV* sv, double num)); |
2247 | |
2248 | =item sv_setpv |
2249 | |
2250 | Copies a string into an SV. The string must be null-terminated. |
2251 | |
2252 | void sv_setpv _((SV* sv, char* ptr)); |
2253 | |
2254 | =item sv_setpvn |
2255 | |
2256 | Copies a string into an SV. The C<len> parameter indicates the number of |
2257 | bytes to be copied. |
2258 | |
2259 | void sv_setpvn _((SV* sv, char* ptr, STRLEN len)); |
2260 | |
2261 | =item sv_setref_iv |
2262 | |
5fb8527f |
2263 | Copies an integer into a new SV, optionally blessing the SV. The C<rv> |
2264 | argument will be upgraded to an RV. That RV will be modified to point to |
2265 | the new SV. The C<classname> argument indicates the package for the |
2266 | blessing. Set C<classname> to C<Nullch> to avoid the blessing. The new SV |
2267 | will be returned and will have a refcount of 1. |
cb1a09d0 |
2268 | |
2269 | SV* sv_setref_iv _((SV *rv, char *classname, IV iv)); |
2270 | |
2271 | =item sv_setref_nv |
2272 | |
5fb8527f |
2273 | Copies a double into a new SV, optionally blessing the SV. The C<rv> |
2274 | argument will be upgraded to an RV. That RV will be modified to point to |
2275 | the new SV. The C<classname> argument indicates the package for the |
2276 | blessing. Set C<classname> to C<Nullch> to avoid the blessing. The new SV |
2277 | will be returned and will have a refcount of 1. |
cb1a09d0 |
2278 | |
2279 | SV* sv_setref_nv _((SV *rv, char *classname, double nv)); |
2280 | |
2281 | =item sv_setref_pv |
2282 | |
5fb8527f |
2283 | Copies a pointer into a new SV, optionally blessing the SV. The C<rv> |
2284 | argument will be upgraded to an RV. That RV will be modified to point to |
2285 | the new SV. If the C<pv> argument is NULL then C<sv_undef> will be placed |
2286 | into the SV. The C<classname> argument indicates the package for the |
2287 | blessing. Set C<classname> to C<Nullch> to avoid the blessing. The new SV |
2288 | will be returned and will have a refcount of 1. |
cb1a09d0 |
2289 | |
2290 | SV* sv_setref_pv _((SV *rv, char *classname, void* pv)); |
2291 | |
2292 | Do not use with integral Perl types such as HV, AV, SV, CV, because those |
2293 | objects will become corrupted by the pointer copy process. |
2294 | |
2295 | Note that C<sv_setref_pvn> copies the string while this copies the pointer. |
2296 | |
2297 | =item sv_setref_pvn |
2298 | |
5fb8527f |
2299 | Copies a string into a new SV, optionally blessing the SV. The length of the |
2300 | string must be specified with C<n>. The C<rv> argument will be upgraded to |
2301 | an RV. That RV will be modified to point to the new SV. The C<classname> |
cb1a09d0 |
2302 | argument indicates the package for the blessing. Set C<classname> to |
2303 | C<Nullch> to avoid the blessing. The new SV will be returned and will have |
2304 | a refcount of 1. |
2305 | |
2306 | SV* sv_setref_pvn _((SV *rv, char *classname, char* pv, I32 n)); |
2307 | |
2308 | Note that C<sv_setref_pv> copies the pointer while this copies the string. |
2309 | |
2310 | =item sv_setsv |
2311 | |
2312 | Copies the contents of the source SV C<ssv> into the destination SV C<dsv>. |
5fb8527f |
2313 | The source SV may be destroyed if it is mortal. |
cb1a09d0 |
2314 | |
2315 | void sv_setsv _((SV* dsv, SV* ssv)); |
2316 | |
2317 | =item SvSTASH |
2318 | |
2319 | Returns the stash of the SV. |
2320 | |
2321 | HV * SvSTASH (SV* sv) |
2322 | |
2323 | =item SVt_IV |
2324 | |
2325 | Integer type flag for scalars. See C<svtype>. |
2326 | |
2327 | =item SVt_PV |
2328 | |
2329 | Pointer type flag for scalars. See C<svtype>. |
2330 | |
2331 | =item SVt_PVAV |
2332 | |
2333 | Type flag for arrays. See C<svtype>. |
2334 | |
2335 | =item SVt_PVCV |
2336 | |
2337 | Type flag for code refs. See C<svtype>. |
2338 | |
2339 | =item SVt_PVHV |
2340 | |
2341 | Type flag for hashes. See C<svtype>. |
2342 | |
2343 | =item SVt_PVMG |
2344 | |
2345 | Type flag for blessed scalars. See C<svtype>. |
2346 | |
2347 | =item SVt_NV |
2348 | |
2349 | Double type flag for scalars. See C<svtype>. |
2350 | |
2351 | =item SvTRUE |
2352 | |
2353 | Returns a boolean indicating whether Perl would evaluate the SV as true or |
2354 | false, defined or undefined. |
2355 | |
2356 | int SvTRUE (SV* sv) |
2357 | |
2358 | =item SvTYPE |
2359 | |
2360 | Returns the type of the SV. See C<svtype>. |
2361 | |
2362 | svtype SvTYPE (SV* sv) |
2363 | |
2364 | =item svtype |
2365 | |
2366 | An enum of flags for Perl types. These are found in the file B<sv.h> in the |
2367 | C<svtype> enum. Test these flags with the C<SvTYPE> macro. |
2368 | |
2369 | =item SvUPGRADE |
2370 | |
5fb8527f |
2371 | Used to upgrade an SV to a more complex form. Uses C<sv_upgrade> to perform |
2372 | the upgrade if necessary. See C<svtype>. |
2373 | |
2374 | bool SvUPGRADE _((SV* sv, svtype mt)); |
2375 | |
2376 | =item sv_upgrade |
2377 | |
2378 | Upgrade an SV to a more complex form. Use C<SvUPGRADE>. See C<svtype>. |
cb1a09d0 |
2379 | |
2380 | =item sv_undef |
2381 | |
2382 | This is the C<undef> SV. Always refer to this as C<&sv_undef>. |
2383 | |
5fb8527f |
2384 | =item sv_unref |
2385 | |
2386 | Unsets the RV status of the SV, and decrements the refcount of whatever was |
2387 | being referenced by the RV. This can almost be thought of as a reversal of |
2388 | C<newSVrv>. See C<SvROK_off>. |
2389 | |
2390 | void sv_unref _((SV* sv)); |
2391 | |
cb1a09d0 |
2392 | =item sv_usepvn |
2393 | |
2394 | Tells an SV to use C<ptr> to find its string value. Normally the string is |
5fb8527f |
2395 | stored inside the SV but sv_usepvn allows the SV to use an outside string. |
2396 | The C<ptr> should point to memory that was allocated by C<malloc>. The |
cb1a09d0 |
2397 | string length, C<len>, must be supplied. This function will realloc the |
2398 | memory pointed to by C<ptr>, so that pointer should not be freed or used by |
2399 | the programmer after giving it to sv_usepvn. |
2400 | |
2401 | void sv_usepvn _((SV* sv, char* ptr, STRLEN len)); |
2402 | |
2403 | =item sv_yes |
2404 | |
2405 | This is the C<true> SV. See C<sv_no>. Always refer to this as C<&sv_yes>. |
2406 | |
2407 | =item THIS |
2408 | |
2409 | Variable which is setup by C<xsubpp> to designate the object in a C++ XSUB. |
2410 | This is always the proper type for the C++ object. See C<CLASS> and |
5fb8527f |
2411 | L<perlxs/"Using XS With C++">. |
cb1a09d0 |
2412 | |
2413 | =item toLOWER |
2414 | |
2415 | Converts the specified character to lowercase. |
2416 | |
2417 | int toLOWER (char c) |
2418 | |
2419 | =item toUPPER |
2420 | |
2421 | Converts the specified character to uppercase. |
2422 | |
2423 | int toUPPER (char c) |
2424 | |
2425 | =item warn |
2426 | |
2427 | This is the XSUB-writer's interface to Perl's C<warn> function. Use this |
2428 | function the same way you use the C C<printf> function. See C<croak()>. |
2429 | |
2430 | =item XPUSHi |
2431 | |
2432 | Push an integer onto the stack, extending the stack if necessary. See |
2433 | C<PUSHi>. |
2434 | |
2435 | XPUSHi(int d) |
2436 | |
2437 | =item XPUSHn |
2438 | |
2439 | Push a double onto the stack, extending the stack if necessary. See |
2440 | C<PUSHn>. |
2441 | |
2442 | XPUSHn(double d) |
2443 | |
2444 | =item XPUSHp |
2445 | |
2446 | Push a string onto the stack, extending the stack if necessary. The C<len> |
2447 | indicates the length of the string. See C<PUSHp>. |
2448 | |
2449 | XPUSHp(char *c, int len) |
2450 | |
2451 | =item XPUSHs |
2452 | |
2453 | Push an SV onto the stack, extending the stack if necessary. See C<PUSHs>. |
2454 | |
2455 | XPUSHs(sv) |
2456 | |
5fb8527f |
2457 | =item XS |
2458 | |
2459 | Macro to declare an XSUB and its C parameter list. This is handled by |
2460 | C<xsubpp>. |
2461 | |
cb1a09d0 |
2462 | =item XSRETURN |
2463 | |
2464 | Return from XSUB, indicating number of items on the stack. This is usually |
2465 | handled by C<xsubpp>. |
2466 | |
5fb8527f |
2467 | XSRETURN(int x); |
cb1a09d0 |
2468 | |
2469 | =item XSRETURN_EMPTY |
2470 | |
5fb8527f |
2471 | Return an empty list from an XSUB immediately. |
cb1a09d0 |
2472 | |
2473 | XSRETURN_EMPTY; |
2474 | |
5fb8527f |
2475 | =item XSRETURN_IV |
2476 | |
2477 | Return an integer from an XSUB immediately. Uses C<XST_mIV>. |
2478 | |
2479 | XSRETURN_IV(IV v); |
2480 | |
cb1a09d0 |
2481 | =item XSRETURN_NO |
2482 | |
5fb8527f |
2483 | Return C<&sv_no> from an XSUB immediately. Uses C<XST_mNO>. |
cb1a09d0 |
2484 | |
2485 | XSRETURN_NO; |
2486 | |
5fb8527f |
2487 | =item XSRETURN_NV |
2488 | |
2489 | Return an double from an XSUB immediately. Uses C<XST_mNV>. |
2490 | |
2491 | XSRETURN_NV(NV v); |
2492 | |
2493 | =item XSRETURN_PV |
2494 | |
2495 | Return a copy of a string from an XSUB immediately. Uses C<XST_mPV>. |
2496 | |
2497 | XSRETURN_PV(char *v); |
2498 | |
cb1a09d0 |
2499 | =item XSRETURN_UNDEF |
2500 | |
5fb8527f |
2501 | Return C<&sv_undef> from an XSUB immediately. Uses C<XST_mUNDEF>. |
cb1a09d0 |
2502 | |
2503 | XSRETURN_UNDEF; |
2504 | |
2505 | =item XSRETURN_YES |
2506 | |
5fb8527f |
2507 | Return C<&sv_yes> from an XSUB immediately. Uses C<XST_mYES>. |
cb1a09d0 |
2508 | |
2509 | XSRETURN_YES; |
2510 | |
5fb8527f |
2511 | =item XST_mIV |
2512 | |
2513 | Place an integer into the specified position C<i> on the stack. The value is |
2514 | stored in a new mortal SV. |
2515 | |
2516 | XST_mIV( int i, IV v ); |
2517 | |
2518 | =item XST_mNV |
2519 | |
2520 | Place a double into the specified position C<i> on the stack. The value is |
2521 | stored in a new mortal SV. |
2522 | |
2523 | XST_mNV( int i, NV v ); |
2524 | |
2525 | =item XST_mNO |
2526 | |
2527 | Place C<&sv_no> into the specified position C<i> on the stack. |
2528 | |
2529 | XST_mNO( int i ); |
2530 | |
2531 | =item XST_mPV |
2532 | |
2533 | Place a copy of a string into the specified position C<i> on the stack. The |
2534 | value is stored in a new mortal SV. |
2535 | |
2536 | XST_mPV( int i, char *v ); |
2537 | |
2538 | =item XST_mUNDEF |
2539 | |
2540 | Place C<&sv_undef> into the specified position C<i> on the stack. |
2541 | |
2542 | XST_mUNDEF( int i ); |
2543 | |
2544 | =item XST_mYES |
2545 | |
2546 | Place C<&sv_yes> into the specified position C<i> on the stack. |
2547 | |
2548 | XST_mYES( int i ); |
2549 | |
2550 | =item XS_VERSION |
2551 | |
2552 | The version identifier for an XS module. This is usually handled |
2553 | automatically by C<ExtUtils::MakeMaker>. See C<XS_VERSION_BOOTCHECK>. |
2554 | |
2555 | =item XS_VERSION_BOOTCHECK |
2556 | |
2557 | Macro to verify that a PM module's $VERSION variable matches the XS module's |
2558 | C<XS_VERSION> variable. This is usually handled automatically by |
2559 | C<xsubpp>. See L<perlxs/"The VERSIONCHECK: Keyword">. |
2560 | |
cb1a09d0 |
2561 | =item Zero |
2562 | |
2563 | The XSUB-writer's interface to the C C<memzero> function. The C<d> is the |
2564 | destination, C<n> is the number of items, and C<t> is the type. |
2565 | |
2566 | (void) Zero( d, n, t ); |
2567 | |
2568 | =back |
2569 | |
2570 | =head1 AUTHOR |
2571 | |
55497cff |
2572 | Jeff Okamoto <okamoto@corp.hp.com> |
cb1a09d0 |
2573 | |
2574 | With lots of help and suggestions from Dean Roehrich, Malcolm Beattie, |
2575 | Andreas Koenig, Paul Hudson, Ilya Zakharevich, Paul Marquess, Neil |
55497cff |
2576 | Bowers, Matthew Green, Tim Bunce, Spider Boardman, and Ulrich Pfeifer. |
cb1a09d0 |
2577 | |
55497cff |
2578 | API Listing by Dean Roehrich <roehrich@cray.com>. |
cb1a09d0 |
2579 | |
2580 | =head1 DATE |
2581 | |
55497cff |
2582 | Version 23.1: 1996/10/19 |