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a0d0e21e LW |
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 | ||
0a753a76 | 11 | =head1 Variables |
12 | ||
5f05dabc | 13 | =head2 Datatypes |
a0d0e21e LW |
14 | |
15 | Perl has three typedefs that handle Perl's three main data types: | |
16 | ||
17 | SV Scalar Value | |
18 | AV Array Value | |
19 | HV Hash Value | |
20 | ||
d1b91892 | 21 | Each typedef has specific routines that manipulate the various data types. |
a0d0e21e LW |
22 | |
23 | =head2 What is an "IV"? | |
24 | ||
5f05dabc | 25 | Perl uses a special typedef IV which is a simple integer type that is |
26 | guaranteed to be large enough to hold a pointer (as well as an integer). | |
a0d0e21e | 27 | |
d1b91892 AD |
28 | Perl also uses two special typedefs, I32 and I16, which will always be at |
29 | least 32-bits and 16-bits long, respectively. | |
a0d0e21e | 30 | |
54310121 | 31 | =head2 Working with SVs |
a0d0e21e LW |
32 | |
33 | An SV can be created and loaded with one command. There are four types of | |
34 | values that can be loaded: an integer value (IV), a double (NV), a string, | |
35 | (PV), and another scalar (SV). | |
36 | ||
9da1e3b5 | 37 | The six routines are: |
a0d0e21e LW |
38 | |
39 | SV* newSViv(IV); | |
40 | SV* newSVnv(double); | |
41 | SV* newSVpv(char*, int); | |
9da1e3b5 | 42 | SV* newSVpvn(char*, int); |
46fc3d4c | 43 | SV* newSVpvf(const char*, ...); |
a0d0e21e LW |
44 | SV* newSVsv(SV*); |
45 | ||
deb3007b | 46 | To change the value of an *already-existing* SV, there are seven routines: |
a0d0e21e LW |
47 | |
48 | void sv_setiv(SV*, IV); | |
deb3007b | 49 | void sv_setuv(SV*, UV); |
a0d0e21e | 50 | void sv_setnv(SV*, double); |
a0d0e21e | 51 | void sv_setpv(SV*, char*); |
46fc3d4c | 52 | void sv_setpvn(SV*, char*, int) |
53 | void sv_setpvf(SV*, const char*, ...); | |
9abd00ed | 54 | void sv_setpvfn(SV*, const char*, STRLEN, va_list *, SV **, I32, bool); |
a0d0e21e LW |
55 | void sv_setsv(SV*, SV*); |
56 | ||
57 | Notice that you can choose to specify the length of the string to be | |
9da1e3b5 MUN |
58 | assigned by using C<sv_setpvn>, C<newSVpvn>, or C<newSVpv>, or you may |
59 | allow Perl to calculate the length by using C<sv_setpv> or by specifying | |
60 | 0 as the second argument to C<newSVpv>. Be warned, though, that Perl will | |
61 | determine the string's length by using C<strlen>, which depends on the | |
9abd00ed GS |
62 | string terminating with a NUL character. |
63 | ||
64 | The arguments of C<sv_setpvf> are processed like C<sprintf>, and the | |
65 | formatted output becomes the value. | |
66 | ||
67 | C<sv_setpvfn> is an analogue of C<vsprintf>, but it allows you to specify | |
68 | either a pointer to a variable argument list or the address and length of | |
69 | an array of SVs. The last argument points to a boolean; on return, if that | |
70 | boolean is true, then locale-specific information has been used to format | |
71 | the string, and the string's contents are therefore untrustworty (see | |
72 | L<perlsec>). This pointer may be NULL if that information is not | |
73 | important. Note that this function requires you to specify the length of | |
74 | the format. | |
75 | ||
9da1e3b5 MUN |
76 | The C<sv_set*()> functions are not generic enough to operate on values |
77 | that have "magic". See L<Magic Virtual Tables> later in this document. | |
a0d0e21e | 78 | |
a3cb178b GS |
79 | All SVs that contain strings should be terminated with a NUL character. |
80 | If it is not NUL-terminated there is a risk of | |
5f05dabc | 81 | core dumps and corruptions from code which passes the string to C |
82 | functions or system calls which expect a NUL-terminated string. | |
83 | Perl's own functions typically add a trailing NUL for this reason. | |
84 | Nevertheless, you should be very careful when you pass a string stored | |
85 | in an SV to a C function or system call. | |
86 | ||
a0d0e21e LW |
87 | To access the actual value that an SV points to, you can use the macros: |
88 | ||
89 | SvIV(SV*) | |
90 | SvNV(SV*) | |
91 | SvPV(SV*, STRLEN len) | |
92 | ||
93 | which will automatically coerce the actual scalar type into an IV, double, | |
94 | or string. | |
95 | ||
96 | In the C<SvPV> macro, the length of the string returned is placed into the | |
97 | variable C<len> (this is a macro, so you do I<not> use C<&len>). If you do not | |
9cde0e7f | 98 | care what the length of the data is, use the global variable C<PL_na>. Remember, |
a0d0e21e | 99 | however, that Perl allows arbitrary strings of data that may both contain |
54310121 | 100 | NULs and might not be terminated by a NUL. |
a0d0e21e | 101 | |
07fa94a1 | 102 | If you want to know if the scalar value is TRUE, you can use: |
a0d0e21e LW |
103 | |
104 | SvTRUE(SV*) | |
105 | ||
106 | Although Perl will automatically grow strings for you, if you need to force | |
107 | Perl to allocate more memory for your SV, you can use the macro | |
108 | ||
109 | SvGROW(SV*, STRLEN newlen) | |
110 | ||
111 | which will determine if more memory needs to be allocated. If so, it will | |
112 | call the function C<sv_grow>. Note that C<SvGROW> can only increase, not | |
5f05dabc | 113 | decrease, the allocated memory of an SV and that it does not automatically |
114 | add a byte for the a trailing NUL (perl's own string functions typically do | |
8ebc5c01 | 115 | C<SvGROW(sv, len + 1)>). |
a0d0e21e LW |
116 | |
117 | If you have an SV and want to know what kind of data Perl thinks is stored | |
118 | in it, you can use the following macros to check the type of SV you have. | |
119 | ||
120 | SvIOK(SV*) | |
121 | SvNOK(SV*) | |
122 | SvPOK(SV*) | |
123 | ||
124 | You can get and set the current length of the string stored in an SV with | |
125 | the following macros: | |
126 | ||
127 | SvCUR(SV*) | |
128 | SvCUR_set(SV*, I32 val) | |
129 | ||
cb1a09d0 AD |
130 | You can also get a pointer to the end of the string stored in the SV |
131 | with the macro: | |
132 | ||
133 | SvEND(SV*) | |
134 | ||
135 | But note that these last three macros are valid only if C<SvPOK()> is true. | |
a0d0e21e | 136 | |
d1b91892 AD |
137 | If you want to append something to the end of string stored in an C<SV*>, |
138 | you can use the following functions: | |
139 | ||
140 | void sv_catpv(SV*, char*); | |
141 | void sv_catpvn(SV*, char*, int); | |
46fc3d4c | 142 | void sv_catpvf(SV*, const char*, ...); |
9abd00ed | 143 | void sv_catpvfn(SV*, const char*, STRLEN, va_list *, SV **, I32, bool); |
d1b91892 AD |
144 | void sv_catsv(SV*, SV*); |
145 | ||
146 | The first function calculates the length of the string to be appended by | |
147 | using C<strlen>. In the second, you specify the length of the string | |
46fc3d4c | 148 | yourself. The third function processes its arguments like C<sprintf> and |
9abd00ed GS |
149 | appends the formatted output. The fourth function works like C<vsprintf>. |
150 | You can specify the address and length of an array of SVs instead of the | |
151 | va_list argument. The fifth function extends the string stored in the first | |
152 | SV with the string stored in the second SV. It also forces the second SV | |
153 | to be interpreted as a string. | |
154 | ||
155 | The C<sv_cat*()> functions are not generic enough to operate on values that | |
156 | have "magic". See L<Magic Virtual Tables> later in this document. | |
d1b91892 | 157 | |
a0d0e21e LW |
158 | If you know the name of a scalar variable, you can get a pointer to its SV |
159 | by using the following: | |
160 | ||
5f05dabc | 161 | SV* perl_get_sv("package::varname", FALSE); |
a0d0e21e LW |
162 | |
163 | This returns NULL if the variable does not exist. | |
164 | ||
d1b91892 | 165 | If you want to know if this variable (or any other SV) is actually C<defined>, |
a0d0e21e LW |
166 | you can call: |
167 | ||
168 | SvOK(SV*) | |
169 | ||
9cde0e7f | 170 | The scalar C<undef> value is stored in an SV instance called C<PL_sv_undef>. Its |
a0d0e21e LW |
171 | address can be used whenever an C<SV*> is needed. |
172 | ||
9cde0e7f GS |
173 | There are also the two values C<PL_sv_yes> and C<PL_sv_no>, which contain Boolean |
174 | TRUE and FALSE values, respectively. Like C<PL_sv_undef>, their addresses can | |
a0d0e21e LW |
175 | be used whenever an C<SV*> is needed. |
176 | ||
9cde0e7f | 177 | Do not be fooled into thinking that C<(SV *) 0> is the same as C<&PL_sv_undef>. |
a0d0e21e LW |
178 | Take this code: |
179 | ||
180 | SV* sv = (SV*) 0; | |
181 | if (I-am-to-return-a-real-value) { | |
182 | sv = sv_2mortal(newSViv(42)); | |
183 | } | |
184 | sv_setsv(ST(0), sv); | |
185 | ||
186 | This code tries to return a new SV (which contains the value 42) if it should | |
04343c6d | 187 | return a real value, or undef otherwise. Instead it has returned a NULL |
a0d0e21e | 188 | pointer which, somewhere down the line, will cause a segmentation violation, |
9cde0e7f | 189 | bus error, or just weird results. Change the zero to C<&PL_sv_undef> in the first |
5f05dabc | 190 | line and all will be well. |
a0d0e21e LW |
191 | |
192 | To free an SV that you've created, call C<SvREFCNT_dec(SV*)>. Normally this | |
3fe9a6f1 | 193 | call is not necessary (see L<Reference Counts and Mortality>). |
a0d0e21e | 194 | |
d1b91892 | 195 | =head2 What's Really Stored in an SV? |
a0d0e21e LW |
196 | |
197 | Recall that the usual method of determining the type of scalar you have is | |
5f05dabc | 198 | to use C<Sv*OK> macros. Because a scalar can be both a number and a string, |
d1b91892 | 199 | usually these macros will always return TRUE and calling the C<Sv*V> |
a0d0e21e LW |
200 | macros will do the appropriate conversion of string to integer/double or |
201 | integer/double to string. | |
202 | ||
203 | If you I<really> need to know if you have an integer, double, or string | |
204 | pointer in an SV, you can use the following three macros instead: | |
205 | ||
206 | SvIOKp(SV*) | |
207 | SvNOKp(SV*) | |
208 | SvPOKp(SV*) | |
209 | ||
210 | These will tell you if you truly have an integer, double, or string pointer | |
d1b91892 | 211 | stored in your SV. The "p" stands for private. |
a0d0e21e | 212 | |
07fa94a1 | 213 | In general, though, it's best to use the C<Sv*V> macros. |
a0d0e21e | 214 | |
54310121 | 215 | =head2 Working with AVs |
a0d0e21e | 216 | |
07fa94a1 JO |
217 | There are two ways to create and load an AV. The first method creates an |
218 | empty AV: | |
a0d0e21e LW |
219 | |
220 | AV* newAV(); | |
221 | ||
54310121 | 222 | The second method both creates the AV and initially populates it with SVs: |
a0d0e21e LW |
223 | |
224 | AV* av_make(I32 num, SV **ptr); | |
225 | ||
5f05dabc | 226 | The second argument points to an array containing C<num> C<SV*>'s. Once the |
54310121 | 227 | AV has been created, the SVs can be destroyed, if so desired. |
a0d0e21e | 228 | |
54310121 | 229 | Once the AV has been created, the following operations are possible on AVs: |
a0d0e21e LW |
230 | |
231 | void av_push(AV*, SV*); | |
232 | SV* av_pop(AV*); | |
233 | SV* av_shift(AV*); | |
234 | void av_unshift(AV*, I32 num); | |
235 | ||
236 | These should be familiar operations, with the exception of C<av_unshift>. | |
237 | This routine adds C<num> elements at the front of the array with the C<undef> | |
238 | value. You must then use C<av_store> (described below) to assign values | |
239 | to these new elements. | |
240 | ||
241 | Here are some other functions: | |
242 | ||
5f05dabc | 243 | I32 av_len(AV*); |
a0d0e21e | 244 | SV** av_fetch(AV*, I32 key, I32 lval); |
a0d0e21e | 245 | SV** av_store(AV*, I32 key, SV* val); |
a0d0e21e | 246 | |
5f05dabc | 247 | The C<av_len> function returns the highest index value in array (just |
248 | like $#array in Perl). If the array is empty, -1 is returned. The | |
249 | C<av_fetch> function returns the value at index C<key>, but if C<lval> | |
250 | is non-zero, then C<av_fetch> will store an undef value at that index. | |
04343c6d GS |
251 | The C<av_store> function stores the value C<val> at index C<key>, and does |
252 | not increment the reference count of C<val>. Thus the caller is responsible | |
253 | for taking care of that, and if C<av_store> returns NULL, the caller will | |
254 | have to decrement the reference count to avoid a memory leak. Note that | |
255 | C<av_fetch> and C<av_store> both return C<SV**>'s, not C<SV*>'s as their | |
256 | return value. | |
d1b91892 | 257 | |
a0d0e21e | 258 | void av_clear(AV*); |
a0d0e21e | 259 | void av_undef(AV*); |
cb1a09d0 | 260 | void av_extend(AV*, I32 key); |
5f05dabc | 261 | |
262 | The C<av_clear> function deletes all the elements in the AV* array, but | |
263 | does not actually delete the array itself. The C<av_undef> function will | |
264 | delete all the elements in the array plus the array itself. The | |
265 | C<av_extend> function extends the array so that it contains C<key> | |
266 | elements. If C<key> is less than the current length of the array, then | |
267 | nothing is done. | |
a0d0e21e LW |
268 | |
269 | If you know the name of an array variable, you can get a pointer to its AV | |
270 | by using the following: | |
271 | ||
5f05dabc | 272 | AV* perl_get_av("package::varname", FALSE); |
a0d0e21e LW |
273 | |
274 | This returns NULL if the variable does not exist. | |
275 | ||
04343c6d GS |
276 | See L<Understanding the Magic of Tied Hashes and Arrays> for more |
277 | information on how to use the array access functions on tied arrays. | |
278 | ||
54310121 | 279 | =head2 Working with HVs |
a0d0e21e LW |
280 | |
281 | To create an HV, you use the following routine: | |
282 | ||
283 | HV* newHV(); | |
284 | ||
54310121 | 285 | Once the HV has been created, the following operations are possible on HVs: |
a0d0e21e LW |
286 | |
287 | SV** hv_store(HV*, char* key, U32 klen, SV* val, U32 hash); | |
288 | SV** hv_fetch(HV*, char* key, U32 klen, I32 lval); | |
289 | ||
5f05dabc | 290 | The C<klen> parameter is the length of the key being passed in (Note that |
291 | you cannot pass 0 in as a value of C<klen> to tell Perl to measure the | |
292 | length of the key). The C<val> argument contains the SV pointer to the | |
54310121 | 293 | scalar being stored, and C<hash> is the precomputed hash value (zero if |
5f05dabc | 294 | you want C<hv_store> to calculate it for you). The C<lval> parameter |
295 | indicates whether this fetch is actually a part of a store operation, in | |
296 | which case a new undefined value will be added to the HV with the supplied | |
297 | key and C<hv_fetch> will return as if the value had already existed. | |
a0d0e21e | 298 | |
5f05dabc | 299 | Remember that C<hv_store> and C<hv_fetch> return C<SV**>'s and not just |
300 | C<SV*>. To access the scalar value, you must first dereference the return | |
301 | value. However, you should check to make sure that the return value is | |
302 | not NULL before dereferencing it. | |
a0d0e21e LW |
303 | |
304 | These two functions check if a hash table entry exists, and deletes it. | |
305 | ||
306 | bool hv_exists(HV*, char* key, U32 klen); | |
d1b91892 | 307 | SV* hv_delete(HV*, char* key, U32 klen, I32 flags); |
a0d0e21e | 308 | |
5f05dabc | 309 | If C<flags> does not include the C<G_DISCARD> flag then C<hv_delete> will |
310 | create and return a mortal copy of the deleted value. | |
311 | ||
a0d0e21e LW |
312 | And more miscellaneous functions: |
313 | ||
314 | void hv_clear(HV*); | |
a0d0e21e | 315 | void hv_undef(HV*); |
5f05dabc | 316 | |
317 | Like their AV counterparts, C<hv_clear> deletes all the entries in the hash | |
318 | table but does not actually delete the hash table. The C<hv_undef> deletes | |
319 | both the entries and the hash table itself. | |
a0d0e21e | 320 | |
d1b91892 AD |
321 | Perl keeps the actual data in linked list of structures with a typedef of HE. |
322 | These contain the actual key and value pointers (plus extra administrative | |
323 | overhead). The key is a string pointer; the value is an C<SV*>. However, | |
324 | once you have an C<HE*>, to get the actual key and value, use the routines | |
325 | specified below. | |
326 | ||
a0d0e21e LW |
327 | I32 hv_iterinit(HV*); |
328 | /* Prepares starting point to traverse hash table */ | |
329 | HE* hv_iternext(HV*); | |
330 | /* Get the next entry, and return a pointer to a | |
331 | structure that has both the key and value */ | |
332 | char* hv_iterkey(HE* entry, I32* retlen); | |
333 | /* Get the key from an HE structure and also return | |
334 | the length of the key string */ | |
cb1a09d0 | 335 | SV* hv_iterval(HV*, HE* entry); |
a0d0e21e LW |
336 | /* Return a SV pointer to the value of the HE |
337 | structure */ | |
cb1a09d0 | 338 | SV* hv_iternextsv(HV*, char** key, I32* retlen); |
d1b91892 AD |
339 | /* This convenience routine combines hv_iternext, |
340 | hv_iterkey, and hv_iterval. The key and retlen | |
341 | arguments are return values for the key and its | |
342 | length. The value is returned in the SV* argument */ | |
a0d0e21e LW |
343 | |
344 | If you know the name of a hash variable, you can get a pointer to its HV | |
345 | by using the following: | |
346 | ||
5f05dabc | 347 | HV* perl_get_hv("package::varname", FALSE); |
a0d0e21e LW |
348 | |
349 | This returns NULL if the variable does not exist. | |
350 | ||
8ebc5c01 | 351 | The hash algorithm is defined in the C<PERL_HASH(hash, key, klen)> macro: |
a0d0e21e LW |
352 | |
353 | i = klen; | |
354 | hash = 0; | |
355 | s = key; | |
356 | while (i--) | |
357 | hash = hash * 33 + *s++; | |
358 | ||
04343c6d GS |
359 | See L<Understanding the Magic of Tied Hashes and Arrays> for more |
360 | information on how to use the hash access functions on tied hashes. | |
361 | ||
1e422769 | 362 | =head2 Hash API Extensions |
363 | ||
364 | Beginning with version 5.004, the following functions are also supported: | |
365 | ||
366 | HE* hv_fetch_ent (HV* tb, SV* key, I32 lval, U32 hash); | |
367 | HE* hv_store_ent (HV* tb, SV* key, SV* val, U32 hash); | |
368 | ||
369 | bool hv_exists_ent (HV* tb, SV* key, U32 hash); | |
370 | SV* hv_delete_ent (HV* tb, SV* key, I32 flags, U32 hash); | |
371 | ||
372 | SV* hv_iterkeysv (HE* entry); | |
373 | ||
374 | Note that these functions take C<SV*> keys, which simplifies writing | |
375 | of extension code that deals with hash structures. These functions | |
376 | also allow passing of C<SV*> keys to C<tie> functions without forcing | |
377 | you to stringify the keys (unlike the previous set of functions). | |
378 | ||
379 | They also return and accept whole hash entries (C<HE*>), making their | |
380 | use more efficient (since the hash number for a particular string | |
381 | doesn't have to be recomputed every time). See L<API LISTING> later in | |
382 | this document for detailed descriptions. | |
383 | ||
384 | The following macros must always be used to access the contents of hash | |
385 | entries. Note that the arguments to these macros must be simple | |
386 | variables, since they may get evaluated more than once. See | |
387 | L<API LISTING> later in this document for detailed descriptions of these | |
388 | macros. | |
389 | ||
390 | HePV(HE* he, STRLEN len) | |
391 | HeVAL(HE* he) | |
392 | HeHASH(HE* he) | |
393 | HeSVKEY(HE* he) | |
394 | HeSVKEY_force(HE* he) | |
395 | HeSVKEY_set(HE* he, SV* sv) | |
396 | ||
397 | These two lower level macros are defined, but must only be used when | |
398 | dealing with keys that are not C<SV*>s: | |
399 | ||
400 | HeKEY(HE* he) | |
401 | HeKLEN(HE* he) | |
402 | ||
04343c6d GS |
403 | Note that both C<hv_store> and C<hv_store_ent> do not increment the |
404 | reference count of the stored C<val>, which is the caller's responsibility. | |
405 | If these functions return a NULL value, the caller will usually have to | |
406 | decrement the reference count of C<val> to avoid a memory leak. | |
1e422769 | 407 | |
a0d0e21e LW |
408 | =head2 References |
409 | ||
d1b91892 AD |
410 | References are a special type of scalar that point to other data types |
411 | (including references). | |
a0d0e21e | 412 | |
07fa94a1 | 413 | To create a reference, use either of the following functions: |
a0d0e21e | 414 | |
5f05dabc | 415 | SV* newRV_inc((SV*) thing); |
416 | SV* newRV_noinc((SV*) thing); | |
a0d0e21e | 417 | |
5f05dabc | 418 | The C<thing> argument can be any of an C<SV*>, C<AV*>, or C<HV*>. The |
07fa94a1 JO |
419 | functions are identical except that C<newRV_inc> increments the reference |
420 | count of the C<thing>, while C<newRV_noinc> does not. For historical | |
421 | reasons, C<newRV> is a synonym for C<newRV_inc>. | |
422 | ||
423 | Once you have a reference, you can use the following macro to dereference | |
424 | the reference: | |
a0d0e21e LW |
425 | |
426 | SvRV(SV*) | |
427 | ||
428 | then call the appropriate routines, casting the returned C<SV*> to either an | |
d1b91892 | 429 | C<AV*> or C<HV*>, if required. |
a0d0e21e | 430 | |
d1b91892 | 431 | To determine if an SV is a reference, you can use the following macro: |
a0d0e21e LW |
432 | |
433 | SvROK(SV*) | |
434 | ||
07fa94a1 JO |
435 | To discover what type of value the reference refers to, use the following |
436 | macro and then check the return value. | |
d1b91892 AD |
437 | |
438 | SvTYPE(SvRV(SV*)) | |
439 | ||
440 | The most useful types that will be returned are: | |
441 | ||
442 | SVt_IV Scalar | |
443 | SVt_NV Scalar | |
444 | SVt_PV Scalar | |
5f05dabc | 445 | SVt_RV Scalar |
d1b91892 AD |
446 | SVt_PVAV Array |
447 | SVt_PVHV Hash | |
448 | SVt_PVCV Code | |
5f05dabc | 449 | SVt_PVGV Glob (possible a file handle) |
450 | SVt_PVMG Blessed or Magical Scalar | |
451 | ||
452 | See the sv.h header file for more details. | |
d1b91892 | 453 | |
cb1a09d0 AD |
454 | =head2 Blessed References and Class Objects |
455 | ||
456 | References are also used to support object-oriented programming. In the | |
457 | OO lexicon, an object is simply a reference that has been blessed into a | |
458 | package (or class). Once blessed, the programmer may now use the reference | |
459 | to access the various methods in the class. | |
460 | ||
461 | A reference can be blessed into a package with the following function: | |
462 | ||
463 | SV* sv_bless(SV* sv, HV* stash); | |
464 | ||
465 | The C<sv> argument must be a reference. The C<stash> argument specifies | |
3fe9a6f1 | 466 | which class the reference will belong to. See |
2ae324a7 | 467 | L<Stashes and Globs> for information on converting class names into stashes. |
cb1a09d0 AD |
468 | |
469 | /* Still under construction */ | |
470 | ||
471 | Upgrades rv to reference if not already one. Creates new SV for rv to | |
8ebc5c01 | 472 | point to. If C<classname> is non-null, the SV is blessed into the specified |
473 | class. SV is returned. | |
cb1a09d0 AD |
474 | |
475 | SV* newSVrv(SV* rv, char* classname); | |
476 | ||
8ebc5c01 | 477 | Copies integer or double into an SV whose reference is C<rv>. SV is blessed |
478 | if C<classname> is non-null. | |
cb1a09d0 AD |
479 | |
480 | SV* sv_setref_iv(SV* rv, char* classname, IV iv); | |
481 | SV* sv_setref_nv(SV* rv, char* classname, NV iv); | |
482 | ||
5f05dabc | 483 | Copies the pointer value (I<the address, not the string!>) into an SV whose |
8ebc5c01 | 484 | reference is rv. SV is blessed if C<classname> is non-null. |
cb1a09d0 AD |
485 | |
486 | SV* sv_setref_pv(SV* rv, char* classname, PV iv); | |
487 | ||
8ebc5c01 | 488 | Copies string into an SV whose reference is C<rv>. Set length to 0 to let |
489 | Perl calculate the string length. SV is blessed if C<classname> is non-null. | |
cb1a09d0 AD |
490 | |
491 | SV* sv_setref_pvn(SV* rv, char* classname, PV iv, int length); | |
492 | ||
9abd00ed GS |
493 | Tests whether the SV is blessed into the specified class. It does not |
494 | check inheritance relationships. | |
495 | ||
496 | int sv_isa(SV* sv, char* name); | |
497 | ||
498 | Tests whether the SV is a reference to a blessed object. | |
499 | ||
500 | int sv_isobject(SV* sv); | |
501 | ||
502 | Tests whether the SV is derived from the specified class. SV can be either | |
503 | a reference to a blessed object or a string containing a class name. This | |
504 | is the function implementing the C<UNIVERSAL::isa> functionality. | |
505 | ||
506 | bool sv_derived_from(SV* sv, char* name); | |
507 | ||
508 | To check if you've got an object derived from a specific class you have | |
509 | to write: | |
510 | ||
511 | if (sv_isobject(sv) && sv_derived_from(sv, class)) { ... } | |
cb1a09d0 | 512 | |
5f05dabc | 513 | =head2 Creating New Variables |
cb1a09d0 | 514 | |
5f05dabc | 515 | To create a new Perl variable with an undef value which can be accessed from |
516 | your Perl script, use the following routines, depending on the variable type. | |
cb1a09d0 | 517 | |
5f05dabc | 518 | SV* perl_get_sv("package::varname", TRUE); |
519 | AV* perl_get_av("package::varname", TRUE); | |
520 | HV* perl_get_hv("package::varname", TRUE); | |
cb1a09d0 AD |
521 | |
522 | Notice the use of TRUE as the second parameter. The new variable can now | |
523 | be set, using the routines appropriate to the data type. | |
524 | ||
5f05dabc | 525 | There are additional macros whose values may be bitwise OR'ed with the |
526 | C<TRUE> argument to enable certain extra features. Those bits are: | |
cb1a09d0 | 527 | |
5f05dabc | 528 | GV_ADDMULTI Marks the variable as multiply defined, thus preventing the |
54310121 | 529 | "Name <varname> used only once: possible typo" warning. |
07fa94a1 JO |
530 | GV_ADDWARN Issues the warning "Had to create <varname> unexpectedly" if |
531 | the variable did not exist before the function was called. | |
cb1a09d0 | 532 | |
07fa94a1 JO |
533 | If you do not specify a package name, the variable is created in the current |
534 | package. | |
cb1a09d0 | 535 | |
5f05dabc | 536 | =head2 Reference Counts and Mortality |
a0d0e21e | 537 | |
54310121 | 538 | Perl uses an reference count-driven garbage collection mechanism. SVs, |
539 | AVs, or HVs (xV for short in the following) start their life with a | |
55497cff | 540 | reference count of 1. If the reference count of an xV ever drops to 0, |
07fa94a1 | 541 | then it will be destroyed and its memory made available for reuse. |
55497cff | 542 | |
543 | This normally doesn't happen at the Perl level unless a variable is | |
5f05dabc | 544 | undef'ed or the last variable holding a reference to it is changed or |
545 | overwritten. At the internal level, however, reference counts can be | |
55497cff | 546 | manipulated with the following macros: |
547 | ||
548 | int SvREFCNT(SV* sv); | |
5f05dabc | 549 | SV* SvREFCNT_inc(SV* sv); |
55497cff | 550 | void SvREFCNT_dec(SV* sv); |
551 | ||
552 | However, there is one other function which manipulates the reference | |
07fa94a1 JO |
553 | count of its argument. The C<newRV_inc> function, you will recall, |
554 | creates a reference to the specified argument. As a side effect, | |
555 | it increments the argument's reference count. If this is not what | |
556 | you want, use C<newRV_noinc> instead. | |
557 | ||
558 | For example, imagine you want to return a reference from an XSUB function. | |
559 | Inside the XSUB routine, you create an SV which initially has a reference | |
560 | count of one. Then you call C<newRV_inc>, passing it the just-created SV. | |
5f05dabc | 561 | This returns the reference as a new SV, but the reference count of the |
562 | SV you passed to C<newRV_inc> has been incremented to two. Now you | |
07fa94a1 JO |
563 | return the reference from the XSUB routine and forget about the SV. |
564 | But Perl hasn't! Whenever the returned reference is destroyed, the | |
565 | reference count of the original SV is decreased to one and nothing happens. | |
566 | The SV will hang around without any way to access it until Perl itself | |
567 | terminates. This is a memory leak. | |
5f05dabc | 568 | |
569 | The correct procedure, then, is to use C<newRV_noinc> instead of | |
faed5253 JO |
570 | C<newRV_inc>. Then, if and when the last reference is destroyed, |
571 | the reference count of the SV will go to zero and it will be destroyed, | |
07fa94a1 | 572 | stopping any memory leak. |
55497cff | 573 | |
5f05dabc | 574 | There are some convenience functions available that can help with the |
54310121 | 575 | destruction of xVs. These functions introduce the concept of "mortality". |
07fa94a1 JO |
576 | An xV that is mortal has had its reference count marked to be decremented, |
577 | but not actually decremented, until "a short time later". Generally the | |
578 | term "short time later" means a single Perl statement, such as a call to | |
54310121 | 579 | an XSUB function. The actual determinant for when mortal xVs have their |
07fa94a1 JO |
580 | reference count decremented depends on two macros, SAVETMPS and FREETMPS. |
581 | See L<perlcall> and L<perlxs> for more details on these macros. | |
55497cff | 582 | |
583 | "Mortalization" then is at its simplest a deferred C<SvREFCNT_dec>. | |
584 | However, if you mortalize a variable twice, the reference count will | |
585 | later be decremented twice. | |
586 | ||
587 | You should be careful about creating mortal variables. Strange things | |
588 | can happen if you make the same value mortal within multiple contexts, | |
5f05dabc | 589 | or if you make a variable mortal multiple times. |
a0d0e21e LW |
590 | |
591 | To create a mortal variable, use the functions: | |
592 | ||
593 | SV* sv_newmortal() | |
594 | SV* sv_2mortal(SV*) | |
595 | SV* sv_mortalcopy(SV*) | |
596 | ||
5f05dabc | 597 | The first call creates a mortal SV, the second converts an existing |
598 | SV to a mortal SV (and thus defers a call to C<SvREFCNT_dec>), and the | |
599 | third creates a mortal copy of an existing SV. | |
a0d0e21e | 600 | |
54310121 | 601 | The mortal routines are not just for SVs -- AVs and HVs can be |
faed5253 | 602 | made mortal by passing their address (type-casted to C<SV*>) to the |
07fa94a1 | 603 | C<sv_2mortal> or C<sv_mortalcopy> routines. |
a0d0e21e | 604 | |
5f05dabc | 605 | =head2 Stashes and Globs |
a0d0e21e | 606 | |
aa689395 | 607 | A "stash" is a hash that contains all of the different objects that |
608 | are contained within a package. Each key of the stash is a symbol | |
609 | name (shared by all the different types of objects that have the same | |
610 | name), and each value in the hash table is a GV (Glob Value). This GV | |
611 | in turn contains references to the various objects of that name, | |
612 | including (but not limited to) the following: | |
cb1a09d0 | 613 | |
a0d0e21e LW |
614 | Scalar Value |
615 | Array Value | |
616 | Hash Value | |
a3cb178b | 617 | I/O Handle |
a0d0e21e LW |
618 | Format |
619 | Subroutine | |
620 | ||
9cde0e7f | 621 | There is a single stash called "PL_defstash" that holds the items that exist |
5f05dabc | 622 | in the "main" package. To get at the items in other packages, append the |
623 | string "::" to the package name. The items in the "Foo" package are in | |
9cde0e7f | 624 | the stash "Foo::" in PL_defstash. The items in the "Bar::Baz" package are |
5f05dabc | 625 | in the stash "Baz::" in "Bar::"'s stash. |
a0d0e21e | 626 | |
d1b91892 | 627 | To get the stash pointer for a particular package, use the function: |
a0d0e21e LW |
628 | |
629 | HV* gv_stashpv(char* name, I32 create) | |
630 | HV* gv_stashsv(SV*, I32 create) | |
631 | ||
632 | The first function takes a literal string, the second uses the string stored | |
d1b91892 | 633 | in the SV. Remember that a stash is just a hash table, so you get back an |
cb1a09d0 | 634 | C<HV*>. The C<create> flag will create a new package if it is set. |
a0d0e21e LW |
635 | |
636 | The name that C<gv_stash*v> wants is the name of the package whose symbol table | |
637 | you want. The default package is called C<main>. If you have multiply nested | |
d1b91892 AD |
638 | packages, pass their names to C<gv_stash*v>, separated by C<::> as in the Perl |
639 | language itself. | |
a0d0e21e LW |
640 | |
641 | Alternately, if you have an SV that is a blessed reference, you can find | |
642 | out the stash pointer by using: | |
643 | ||
644 | HV* SvSTASH(SvRV(SV*)); | |
645 | ||
646 | then use the following to get the package name itself: | |
647 | ||
648 | char* HvNAME(HV* stash); | |
649 | ||
5f05dabc | 650 | If you need to bless or re-bless an object you can use the following |
651 | function: | |
a0d0e21e LW |
652 | |
653 | SV* sv_bless(SV*, HV* stash) | |
654 | ||
655 | where the first argument, an C<SV*>, must be a reference, and the second | |
656 | argument is a stash. The returned C<SV*> can now be used in the same way | |
657 | as any other SV. | |
658 | ||
d1b91892 AD |
659 | For more information on references and blessings, consult L<perlref>. |
660 | ||
54310121 | 661 | =head2 Double-Typed SVs |
0a753a76 | 662 | |
663 | Scalar variables normally contain only one type of value, an integer, | |
664 | double, pointer, or reference. Perl will automatically convert the | |
665 | actual scalar data from the stored type into the requested type. | |
666 | ||
667 | Some scalar variables contain more than one type of scalar data. For | |
668 | example, the variable C<$!> contains either the numeric value of C<errno> | |
669 | or its string equivalent from either C<strerror> or C<sys_errlist[]>. | |
670 | ||
671 | To force multiple data values into an SV, you must do two things: use the | |
672 | C<sv_set*v> routines to add the additional scalar type, then set a flag | |
673 | so that Perl will believe it contains more than one type of data. The | |
674 | four macros to set the flags are: | |
675 | ||
676 | SvIOK_on | |
677 | SvNOK_on | |
678 | SvPOK_on | |
679 | SvROK_on | |
680 | ||
681 | The particular macro you must use depends on which C<sv_set*v> routine | |
682 | you called first. This is because every C<sv_set*v> routine turns on | |
683 | only the bit for the particular type of data being set, and turns off | |
684 | all the rest. | |
685 | ||
686 | For example, to create a new Perl variable called "dberror" that contains | |
687 | both the numeric and descriptive string error values, you could use the | |
688 | following code: | |
689 | ||
690 | extern int dberror; | |
691 | extern char *dberror_list; | |
692 | ||
693 | SV* sv = perl_get_sv("dberror", TRUE); | |
694 | sv_setiv(sv, (IV) dberror); | |
695 | sv_setpv(sv, dberror_list[dberror]); | |
696 | SvIOK_on(sv); | |
697 | ||
698 | If the order of C<sv_setiv> and C<sv_setpv> had been reversed, then the | |
699 | macro C<SvPOK_on> would need to be called instead of C<SvIOK_on>. | |
700 | ||
701 | =head2 Magic Variables | |
a0d0e21e | 702 | |
d1b91892 AD |
703 | [This section still under construction. Ignore everything here. Post no |
704 | bills. Everything not permitted is forbidden.] | |
705 | ||
d1b91892 AD |
706 | Any SV may be magical, that is, it has special features that a normal |
707 | SV does not have. These features are stored in the SV structure in a | |
5f05dabc | 708 | linked list of C<struct magic>'s, typedef'ed to C<MAGIC>. |
d1b91892 AD |
709 | |
710 | struct magic { | |
711 | MAGIC* mg_moremagic; | |
712 | MGVTBL* mg_virtual; | |
713 | U16 mg_private; | |
714 | char mg_type; | |
715 | U8 mg_flags; | |
716 | SV* mg_obj; | |
717 | char* mg_ptr; | |
718 | I32 mg_len; | |
719 | }; | |
720 | ||
721 | Note this is current as of patchlevel 0, and could change at any time. | |
722 | ||
723 | =head2 Assigning Magic | |
724 | ||
725 | Perl adds magic to an SV using the sv_magic function: | |
726 | ||
727 | void sv_magic(SV* sv, SV* obj, int how, char* name, I32 namlen); | |
728 | ||
729 | The C<sv> argument is a pointer to the SV that is to acquire a new magical | |
730 | feature. | |
731 | ||
732 | If C<sv> is not already magical, Perl uses the C<SvUPGRADE> macro to | |
733 | set the C<SVt_PVMG> flag for the C<sv>. Perl then continues by adding | |
734 | it to the beginning of the linked list of magical features. Any prior | |
735 | entry of the same type of magic is deleted. Note that this can be | |
5fb8527f | 736 | overridden, and multiple instances of the same type of magic can be |
d1b91892 AD |
737 | associated with an SV. |
738 | ||
54310121 | 739 | The C<name> and C<namlen> arguments are used to associate a string with |
740 | the magic, typically the name of a variable. C<namlen> is stored in the | |
741 | C<mg_len> field and if C<name> is non-null and C<namlen> >= 0 a malloc'd | |
d1b91892 AD |
742 | copy of the name is stored in C<mg_ptr> field. |
743 | ||
744 | The sv_magic function uses C<how> to determine which, if any, predefined | |
745 | "Magic Virtual Table" should be assigned to the C<mg_virtual> field. | |
cb1a09d0 AD |
746 | See the "Magic Virtual Table" section below. The C<how> argument is also |
747 | stored in the C<mg_type> field. | |
d1b91892 AD |
748 | |
749 | The C<obj> argument is stored in the C<mg_obj> field of the C<MAGIC> | |
750 | structure. If it is not the same as the C<sv> argument, the reference | |
751 | count of the C<obj> object is incremented. If it is the same, or if | |
04343c6d | 752 | the C<how> argument is "#", or if it is a NULL pointer, then C<obj> is |
d1b91892 AD |
753 | merely stored, without the reference count being incremented. |
754 | ||
cb1a09d0 AD |
755 | There is also a function to add magic to an C<HV>: |
756 | ||
757 | void hv_magic(HV *hv, GV *gv, int how); | |
758 | ||
759 | This simply calls C<sv_magic> and coerces the C<gv> argument into an C<SV>. | |
760 | ||
761 | To remove the magic from an SV, call the function sv_unmagic: | |
762 | ||
763 | void sv_unmagic(SV *sv, int type); | |
764 | ||
765 | The C<type> argument should be equal to the C<how> value when the C<SV> | |
766 | was initially made magical. | |
767 | ||
d1b91892 AD |
768 | =head2 Magic Virtual Tables |
769 | ||
770 | The C<mg_virtual> field in the C<MAGIC> structure is a pointer to a | |
771 | C<MGVTBL>, which is a structure of function pointers and stands for | |
772 | "Magic Virtual Table" to handle the various operations that might be | |
773 | applied to that variable. | |
774 | ||
775 | The C<MGVTBL> has five pointers to the following routine types: | |
776 | ||
777 | int (*svt_get)(SV* sv, MAGIC* mg); | |
778 | int (*svt_set)(SV* sv, MAGIC* mg); | |
779 | U32 (*svt_len)(SV* sv, MAGIC* mg); | |
780 | int (*svt_clear)(SV* sv, MAGIC* mg); | |
781 | int (*svt_free)(SV* sv, MAGIC* mg); | |
782 | ||
783 | This MGVTBL structure is set at compile-time in C<perl.h> and there are | |
784 | currently 19 types (or 21 with overloading turned on). These different | |
785 | structures contain pointers to various routines that perform additional | |
786 | actions depending on which function is being called. | |
787 | ||
788 | Function pointer Action taken | |
789 | ---------------- ------------ | |
790 | svt_get Do something after the value of the SV is retrieved. | |
791 | svt_set Do something after the SV is assigned a value. | |
792 | svt_len Report on the SV's length. | |
793 | svt_clear Clear something the SV represents. | |
794 | svt_free Free any extra storage associated with the SV. | |
795 | ||
796 | For instance, the MGVTBL structure called C<vtbl_sv> (which corresponds | |
797 | to an C<mg_type> of '\0') contains: | |
798 | ||
799 | { magic_get, magic_set, magic_len, 0, 0 } | |
800 | ||
801 | Thus, when an SV is determined to be magical and of type '\0', if a get | |
802 | operation is being performed, the routine C<magic_get> is called. All | |
803 | the various routines for the various magical types begin with C<magic_>. | |
804 | ||
805 | The current kinds of Magic Virtual Tables are: | |
806 | ||
bdbeb323 | 807 | mg_type MGVTBL Type of magic |
5f05dabc | 808 | ------- ------ ---------------------------- |
bdbeb323 SM |
809 | \0 vtbl_sv Special scalar variable |
810 | A vtbl_amagic %OVERLOAD hash | |
811 | a vtbl_amagicelem %OVERLOAD hash element | |
812 | c (none) Holds overload table (AMT) on stash | |
813 | B vtbl_bm Boyer-Moore (fast string search) | |
d1b91892 AD |
814 | E vtbl_env %ENV hash |
815 | e vtbl_envelem %ENV hash element | |
bdbeb323 SM |
816 | f vtbl_fm Formline ('compiled' format) |
817 | g vtbl_mglob m//g target / study()ed string | |
d1b91892 AD |
818 | I vtbl_isa @ISA array |
819 | i vtbl_isaelem @ISA array element | |
bdbeb323 SM |
820 | k vtbl_nkeys scalar(keys()) lvalue |
821 | L (none) Debugger %_<filename | |
822 | l vtbl_dbline Debugger %_<filename element | |
44a8e56a | 823 | o vtbl_collxfrm Locale transformation |
bdbeb323 SM |
824 | P vtbl_pack Tied array or hash |
825 | p vtbl_packelem Tied array or hash element | |
826 | q vtbl_packelem Tied scalar or handle | |
827 | S vtbl_sig %SIG hash | |
828 | s vtbl_sigelem %SIG hash element | |
d1b91892 | 829 | t vtbl_taint Taintedness |
bdbeb323 SM |
830 | U vtbl_uvar Available for use by extensions |
831 | v vtbl_vec vec() lvalue | |
832 | x vtbl_substr substr() lvalue | |
833 | y vtbl_defelem Shadow "foreach" iterator variable / | |
834 | smart parameter vivification | |
835 | * vtbl_glob GV (typeglob) | |
836 | # vtbl_arylen Array length ($#ary) | |
837 | . vtbl_pos pos() lvalue | |
838 | ~ (none) Available for use by extensions | |
d1b91892 | 839 | |
68dc0745 | 840 | When an uppercase and lowercase letter both exist in the table, then the |
841 | uppercase letter is used to represent some kind of composite type (a list | |
842 | or a hash), and the lowercase letter is used to represent an element of | |
d1b91892 AD |
843 | that composite type. |
844 | ||
bdbeb323 SM |
845 | The '~' and 'U' magic types are defined specifically for use by |
846 | extensions and will not be used by perl itself. Extensions can use | |
847 | '~' magic to 'attach' private information to variables (typically | |
848 | objects). This is especially useful because there is no way for | |
849 | normal perl code to corrupt this private information (unlike using | |
850 | extra elements of a hash object). | |
851 | ||
852 | Similarly, 'U' magic can be used much like tie() to call a C function | |
853 | any time a scalar's value is used or changed. The C<MAGIC>'s | |
854 | C<mg_ptr> field points to a C<ufuncs> structure: | |
855 | ||
856 | struct ufuncs { | |
857 | I32 (*uf_val)(IV, SV*); | |
858 | I32 (*uf_set)(IV, SV*); | |
859 | IV uf_index; | |
860 | }; | |
861 | ||
862 | When the SV is read from or written to, the C<uf_val> or C<uf_set> | |
863 | function will be called with C<uf_index> as the first arg and a | |
864 | pointer to the SV as the second. | |
5f05dabc | 865 | |
bdbeb323 SM |
866 | Note that because multiple extensions may be using '~' or 'U' magic, |
867 | it is important for extensions to take extra care to avoid conflict. | |
868 | Typically only using the magic on objects blessed into the same class | |
869 | as the extension is sufficient. For '~' magic, it may also be | |
870 | appropriate to add an I32 'signature' at the top of the private data | |
871 | area and check that. | |
5f05dabc | 872 | |
ef50df4b GS |
873 | Also note that the C<sv_set*()> and C<sv_cat*()> functions described |
874 | earlier do B<not> invoke 'set' magic on their targets. This must | |
875 | be done by the user either by calling the C<SvSETMAGIC()> macro after | |
876 | calling these functions, or by using one of the C<sv_set*_mg()> or | |
877 | C<sv_cat*_mg()> functions. Similarly, generic C code must call the | |
878 | C<SvGETMAGIC()> macro to invoke any 'get' magic if they use an SV | |
879 | obtained from external sources in functions that don't handle magic. | |
880 | L<API LISTING> later in this document identifies such functions. | |
189b2af5 GS |
881 | For example, calls to the C<sv_cat*()> functions typically need to be |
882 | followed by C<SvSETMAGIC()>, but they don't need a prior C<SvGETMAGIC()> | |
883 | since their implementation handles 'get' magic. | |
884 | ||
d1b91892 AD |
885 | =head2 Finding Magic |
886 | ||
887 | MAGIC* mg_find(SV*, int type); /* Finds the magic pointer of that type */ | |
888 | ||
889 | This routine returns a pointer to the C<MAGIC> structure stored in the SV. | |
890 | If the SV does not have that magical feature, C<NULL> is returned. Also, | |
54310121 | 891 | if the SV is not of type SVt_PVMG, Perl may core dump. |
d1b91892 AD |
892 | |
893 | int mg_copy(SV* sv, SV* nsv, char* key, STRLEN klen); | |
894 | ||
895 | This routine checks to see what types of magic C<sv> has. If the mg_type | |
68dc0745 | 896 | field is an uppercase letter, then the mg_obj is copied to C<nsv>, but |
897 | the mg_type field is changed to be the lowercase letter. | |
a0d0e21e | 898 | |
04343c6d GS |
899 | =head2 Understanding the Magic of Tied Hashes and Arrays |
900 | ||
901 | Tied hashes and arrays are magical beasts of the 'P' magic type. | |
9edb2b46 GS |
902 | |
903 | WARNING: As of the 5.004 release, proper usage of the array and hash | |
904 | access functions requires understanding a few caveats. Some | |
905 | of these caveats are actually considered bugs in the API, to be fixed | |
906 | in later releases, and are bracketed with [MAYCHANGE] below. If | |
907 | you find yourself actually applying such information in this section, be | |
908 | aware that the behavior may change in the future, umm, without warning. | |
04343c6d GS |
909 | |
910 | The C<av_store> function, when given a tied array argument, merely | |
911 | copies the magic of the array onto the value to be "stored", using | |
912 | C<mg_copy>. It may also return NULL, indicating that the value did not | |
9edb2b46 GS |
913 | actually need to be stored in the array. [MAYCHANGE] After a call to |
914 | C<av_store> on a tied array, the caller will usually need to call | |
915 | C<mg_set(val)> to actually invoke the perl level "STORE" method on the | |
916 | TIEARRAY object. If C<av_store> did return NULL, a call to | |
917 | C<SvREFCNT_dec(val)> will also be usually necessary to avoid a memory | |
918 | leak. [/MAYCHANGE] | |
04343c6d GS |
919 | |
920 | The previous paragraph is applicable verbatim to tied hash access using the | |
921 | C<hv_store> and C<hv_store_ent> functions as well. | |
922 | ||
923 | C<av_fetch> and the corresponding hash functions C<hv_fetch> and | |
924 | C<hv_fetch_ent> actually return an undefined mortal value whose magic | |
925 | has been initialized using C<mg_copy>. Note the value so returned does not | |
9edb2b46 GS |
926 | need to be deallocated, as it is already mortal. [MAYCHANGE] But you will |
927 | need to call C<mg_get()> on the returned value in order to actually invoke | |
928 | the perl level "FETCH" method on the underlying TIE object. Similarly, | |
04343c6d GS |
929 | you may also call C<mg_set()> on the return value after possibly assigning |
930 | a suitable value to it using C<sv_setsv>, which will invoke the "STORE" | |
9edb2b46 | 931 | method on the TIE object. [/MAYCHANGE] |
04343c6d | 932 | |
9edb2b46 | 933 | [MAYCHANGE] |
04343c6d GS |
934 | In other words, the array or hash fetch/store functions don't really |
935 | fetch and store actual values in the case of tied arrays and hashes. They | |
936 | merely call C<mg_copy> to attach magic to the values that were meant to be | |
937 | "stored" or "fetched". Later calls to C<mg_get> and C<mg_set> actually | |
938 | do the job of invoking the TIE methods on the underlying objects. Thus | |
9edb2b46 | 939 | the magic mechanism currently implements a kind of lazy access to arrays |
04343c6d GS |
940 | and hashes. |
941 | ||
942 | Currently (as of perl version 5.004), use of the hash and array access | |
943 | functions requires the user to be aware of whether they are operating on | |
9edb2b46 GS |
944 | "normal" hashes and arrays, or on their tied variants. The API may be |
945 | changed to provide more transparent access to both tied and normal data | |
946 | types in future versions. | |
947 | [/MAYCHANGE] | |
04343c6d GS |
948 | |
949 | You would do well to understand that the TIEARRAY and TIEHASH interfaces | |
950 | are mere sugar to invoke some perl method calls while using the uniform hash | |
951 | and array syntax. The use of this sugar imposes some overhead (typically | |
952 | about two to four extra opcodes per FETCH/STORE operation, in addition to | |
953 | the creation of all the mortal variables required to invoke the methods). | |
954 | This overhead will be comparatively small if the TIE methods are themselves | |
955 | substantial, but if they are only a few statements long, the overhead | |
956 | will not be insignificant. | |
957 | ||
d1c897a1 IZ |
958 | =head2 Localizing changes |
959 | ||
960 | Perl has a very handy construction | |
961 | ||
962 | { | |
963 | local $var = 2; | |
964 | ... | |
965 | } | |
966 | ||
967 | This construction is I<approximately> equivalent to | |
968 | ||
969 | { | |
970 | my $oldvar = $var; | |
971 | $var = 2; | |
972 | ... | |
973 | $var = $oldvar; | |
974 | } | |
975 | ||
976 | The biggest difference is that the first construction would | |
977 | reinstate the initial value of $var, irrespective of how control exits | |
978 | the block: C<goto>, C<return>, C<die>/C<eval> etc. It is a little bit | |
979 | more efficient as well. | |
980 | ||
981 | There is a way to achieve a similar task from C via Perl API: create a | |
982 | I<pseudo-block>, and arrange for some changes to be automatically | |
983 | undone at the end of it, either explicit, or via a non-local exit (via | |
984 | die()). A I<block>-like construct is created by a pair of | |
985 | C<ENTER>/C<LEAVE> macros (see L<perlcall/EXAMPLE/"Returning a | |
986 | Scalar">). Such a construct may be created specially for some | |
987 | important localized task, or an existing one (like boundaries of | |
988 | enclosing Perl subroutine/block, or an existing pair for freeing TMPs) | |
989 | may be used. (In the second case the overhead of additional | |
990 | localization must be almost negligible.) Note that any XSUB is | |
991 | automatically enclosed in an C<ENTER>/C<LEAVE> pair. | |
992 | ||
993 | Inside such a I<pseudo-block> the following service is available: | |
994 | ||
995 | =over | |
996 | ||
997 | =item C<SAVEINT(int i)> | |
998 | ||
999 | =item C<SAVEIV(IV i)> | |
1000 | ||
1001 | =item C<SAVEI32(I32 i)> | |
1002 | ||
1003 | =item C<SAVELONG(long i)> | |
1004 | ||
1005 | These macros arrange things to restore the value of integer variable | |
1006 | C<i> at the end of enclosing I<pseudo-block>. | |
1007 | ||
1008 | =item C<SAVESPTR(s)> | |
1009 | ||
1010 | =item C<SAVEPPTR(p)> | |
1011 | ||
1012 | These macros arrange things to restore the value of pointers C<s> and | |
1013 | C<p>. C<s> must be a pointer of a type which survives conversion to | |
1014 | C<SV*> and back, C<p> should be able to survive conversion to C<char*> | |
1015 | and back. | |
1016 | ||
1017 | =item C<SAVEFREESV(SV *sv)> | |
1018 | ||
1019 | The refcount of C<sv> would be decremented at the end of | |
1020 | I<pseudo-block>. This is similar to C<sv_2mortal>, which should (?) be | |
1021 | used instead. | |
1022 | ||
1023 | =item C<SAVEFREEOP(OP *op)> | |
1024 | ||
1025 | The C<OP *> is op_free()ed at the end of I<pseudo-block>. | |
1026 | ||
1027 | =item C<SAVEFREEPV(p)> | |
1028 | ||
1029 | The chunk of memory which is pointed to by C<p> is Safefree()ed at the | |
1030 | end of I<pseudo-block>. | |
1031 | ||
1032 | =item C<SAVECLEARSV(SV *sv)> | |
1033 | ||
1034 | Clears a slot in the current scratchpad which corresponds to C<sv> at | |
1035 | the end of I<pseudo-block>. | |
1036 | ||
1037 | =item C<SAVEDELETE(HV *hv, char *key, I32 length)> | |
1038 | ||
1039 | The key C<key> of C<hv> is deleted at the end of I<pseudo-block>. The | |
1040 | string pointed to by C<key> is Safefree()ed. If one has a I<key> in | |
1041 | short-lived storage, the corresponding string may be reallocated like | |
1042 | this: | |
1043 | ||
9cde0e7f | 1044 | SAVEDELETE(PL_defstash, savepv(tmpbuf), strlen(tmpbuf)); |
d1c897a1 IZ |
1045 | |
1046 | =item C<SAVEDESTRUCTOR(f,p)> | |
1047 | ||
1048 | At the end of I<pseudo-block> the function C<f> is called with the | |
1049 | only argument (of type C<void*>) C<p>. | |
1050 | ||
1051 | =item C<SAVESTACK_POS()> | |
1052 | ||
1053 | The current offset on the Perl internal stack (cf. C<SP>) is restored | |
1054 | at the end of I<pseudo-block>. | |
1055 | ||
1056 | =back | |
1057 | ||
1058 | The following API list contains functions, thus one needs to | |
1059 | provide pointers to the modifiable data explicitly (either C pointers, | |
1060 | or Perlish C<GV *>s). Where the above macros take C<int>, a similar | |
1061 | function takes C<int *>. | |
1062 | ||
1063 | =over | |
1064 | ||
1065 | =item C<SV* save_scalar(GV *gv)> | |
1066 | ||
1067 | Equivalent to Perl code C<local $gv>. | |
1068 | ||
1069 | =item C<AV* save_ary(GV *gv)> | |
1070 | ||
1071 | =item C<HV* save_hash(GV *gv)> | |
1072 | ||
1073 | Similar to C<save_scalar>, but localize C<@gv> and C<%gv>. | |
1074 | ||
1075 | =item C<void save_item(SV *item)> | |
1076 | ||
1077 | Duplicates the current value of C<SV>, on the exit from the current | |
1078 | C<ENTER>/C<LEAVE> I<pseudo-block> will restore the value of C<SV> | |
1079 | using the stored value. | |
1080 | ||
1081 | =item C<void save_list(SV **sarg, I32 maxsarg)> | |
1082 | ||
1083 | A variant of C<save_item> which takes multiple arguments via an array | |
1084 | C<sarg> of C<SV*> of length C<maxsarg>. | |
1085 | ||
1086 | =item C<SV* save_svref(SV **sptr)> | |
1087 | ||
1088 | Similar to C<save_scalar>, but will reinstate a C<SV *>. | |
1089 | ||
1090 | =item C<void save_aptr(AV **aptr)> | |
1091 | ||
1092 | =item C<void save_hptr(HV **hptr)> | |
1093 | ||
1094 | Similar to C<save_svref>, but localize C<AV *> and C<HV *>. | |
1095 | ||
1096 | =back | |
1097 | ||
1098 | The C<Alias> module implements localization of the basic types within the | |
1099 | I<caller's scope>. People who are interested in how to localize things in | |
1100 | the containing scope should take a look there too. | |
1101 | ||
0a753a76 | 1102 | =head1 Subroutines |
a0d0e21e | 1103 | |
68dc0745 | 1104 | =head2 XSUBs and the Argument Stack |
5f05dabc | 1105 | |
1106 | The XSUB mechanism is a simple way for Perl programs to access C subroutines. | |
1107 | An XSUB routine will have a stack that contains the arguments from the Perl | |
1108 | program, and a way to map from the Perl data structures to a C equivalent. | |
1109 | ||
1110 | The stack arguments are accessible through the C<ST(n)> macro, which returns | |
1111 | the C<n>'th stack argument. Argument 0 is the first argument passed in the | |
1112 | Perl subroutine call. These arguments are C<SV*>, and can be used anywhere | |
1113 | an C<SV*> is used. | |
1114 | ||
1115 | Most of the time, output from the C routine can be handled through use of | |
1116 | the RETVAL and OUTPUT directives. However, there are some cases where the | |
1117 | argument stack is not already long enough to handle all the return values. | |
1118 | An example is the POSIX tzname() call, which takes no arguments, but returns | |
1119 | two, the local time zone's standard and summer time abbreviations. | |
1120 | ||
1121 | To handle this situation, the PPCODE directive is used and the stack is | |
1122 | extended using the macro: | |
1123 | ||
924508f0 | 1124 | EXTEND(SP, num); |
5f05dabc | 1125 | |
924508f0 GS |
1126 | where C<SP> is the macro that represents the local copy of the stack pointer, |
1127 | and C<num> is the number of elements the stack should be extended by. | |
5f05dabc | 1128 | |
1129 | Now that there is room on the stack, values can be pushed on it using the | |
54310121 | 1130 | macros to push IVs, doubles, strings, and SV pointers respectively: |
5f05dabc | 1131 | |
1132 | PUSHi(IV) | |
1133 | PUSHn(double) | |
1134 | PUSHp(char*, I32) | |
1135 | PUSHs(SV*) | |
1136 | ||
1137 | And now the Perl program calling C<tzname>, the two values will be assigned | |
1138 | as in: | |
1139 | ||
1140 | ($standard_abbrev, $summer_abbrev) = POSIX::tzname; | |
1141 | ||
1142 | An alternate (and possibly simpler) method to pushing values on the stack is | |
1143 | to use the macros: | |
1144 | ||
1145 | XPUSHi(IV) | |
1146 | XPUSHn(double) | |
1147 | XPUSHp(char*, I32) | |
1148 | XPUSHs(SV*) | |
1149 | ||
1150 | These macros automatically adjust the stack for you, if needed. Thus, you | |
1151 | do not need to call C<EXTEND> to extend the stack. | |
1152 | ||
1153 | For more information, consult L<perlxs> and L<perlxstut>. | |
1154 | ||
1155 | =head2 Calling Perl Routines from within C Programs | |
a0d0e21e LW |
1156 | |
1157 | There are four routines that can be used to call a Perl subroutine from | |
1158 | within a C program. These four are: | |
1159 | ||
1160 | I32 perl_call_sv(SV*, I32); | |
1161 | I32 perl_call_pv(char*, I32); | |
1162 | I32 perl_call_method(char*, I32); | |
1163 | I32 perl_call_argv(char*, I32, register char**); | |
1164 | ||
d1b91892 AD |
1165 | The routine most often used is C<perl_call_sv>. The C<SV*> argument |
1166 | contains either the name of the Perl subroutine to be called, or a | |
1167 | reference to the subroutine. The second argument consists of flags | |
1168 | that control the context in which the subroutine is called, whether | |
1169 | or not the subroutine is being passed arguments, how errors should be | |
1170 | trapped, and how to treat return values. | |
a0d0e21e LW |
1171 | |
1172 | All four routines return the number of arguments that the subroutine returned | |
1173 | on the Perl stack. | |
1174 | ||
d1b91892 AD |
1175 | When using any of these routines (except C<perl_call_argv>), the programmer |
1176 | must manipulate the Perl stack. These include the following macros and | |
1177 | functions: | |
a0d0e21e LW |
1178 | |
1179 | dSP | |
924508f0 | 1180 | SP |
a0d0e21e LW |
1181 | PUSHMARK() |
1182 | PUTBACK | |
1183 | SPAGAIN | |
1184 | ENTER | |
1185 | SAVETMPS | |
1186 | FREETMPS | |
1187 | LEAVE | |
1188 | XPUSH*() | |
cb1a09d0 | 1189 | POP*() |
a0d0e21e | 1190 | |
5f05dabc | 1191 | For a detailed description of calling conventions from C to Perl, |
1192 | consult L<perlcall>. | |
a0d0e21e | 1193 | |
5f05dabc | 1194 | =head2 Memory Allocation |
a0d0e21e | 1195 | |
5f05dabc | 1196 | It is suggested that you use the version of malloc that is distributed |
1197 | with Perl. It keeps pools of various sizes of unallocated memory in | |
07fa94a1 JO |
1198 | order to satisfy allocation requests more quickly. However, on some |
1199 | platforms, it may cause spurious malloc or free errors. | |
d1b91892 AD |
1200 | |
1201 | New(x, pointer, number, type); | |
1202 | Newc(x, pointer, number, type, cast); | |
1203 | Newz(x, pointer, number, type); | |
1204 | ||
07fa94a1 | 1205 | These three macros are used to initially allocate memory. |
5f05dabc | 1206 | |
1207 | The first argument C<x> was a "magic cookie" that was used to keep track | |
1208 | of who called the macro, to help when debugging memory problems. However, | |
07fa94a1 JO |
1209 | the current code makes no use of this feature (most Perl developers now |
1210 | use run-time memory checkers), so this argument can be any number. | |
5f05dabc | 1211 | |
1212 | The second argument C<pointer> should be the name of a variable that will | |
1213 | point to the newly allocated memory. | |
d1b91892 | 1214 | |
d1b91892 AD |
1215 | The third and fourth arguments C<number> and C<type> specify how many of |
1216 | the specified type of data structure should be allocated. The argument | |
1217 | C<type> is passed to C<sizeof>. The final argument to C<Newc>, C<cast>, | |
1218 | should be used if the C<pointer> argument is different from the C<type> | |
1219 | argument. | |
1220 | ||
1221 | Unlike the C<New> and C<Newc> macros, the C<Newz> macro calls C<memzero> | |
1222 | to zero out all the newly allocated memory. | |
1223 | ||
1224 | Renew(pointer, number, type); | |
1225 | Renewc(pointer, number, type, cast); | |
1226 | Safefree(pointer) | |
1227 | ||
1228 | These three macros are used to change a memory buffer size or to free a | |
1229 | piece of memory no longer needed. The arguments to C<Renew> and C<Renewc> | |
1230 | match those of C<New> and C<Newc> with the exception of not needing the | |
1231 | "magic cookie" argument. | |
1232 | ||
1233 | Move(source, dest, number, type); | |
1234 | Copy(source, dest, number, type); | |
1235 | Zero(dest, number, type); | |
1236 | ||
1237 | These three macros are used to move, copy, or zero out previously allocated | |
1238 | memory. The C<source> and C<dest> arguments point to the source and | |
1239 | destination starting points. Perl will move, copy, or zero out C<number> | |
1240 | instances of the size of the C<type> data structure (using the C<sizeof> | |
1241 | function). | |
a0d0e21e | 1242 | |
5f05dabc | 1243 | =head2 PerlIO |
ce3d39e2 | 1244 | |
5f05dabc | 1245 | The most recent development releases of Perl has been experimenting with |
1246 | removing Perl's dependency on the "normal" standard I/O suite and allowing | |
1247 | other stdio implementations to be used. This involves creating a new | |
1248 | abstraction layer that then calls whichever implementation of stdio Perl | |
68dc0745 | 1249 | was compiled with. All XSUBs should now use the functions in the PerlIO |
5f05dabc | 1250 | abstraction layer and not make any assumptions about what kind of stdio |
1251 | is being used. | |
1252 | ||
1253 | For a complete description of the PerlIO abstraction, consult L<perlapio>. | |
1254 | ||
8ebc5c01 | 1255 | =head2 Putting a C value on Perl stack |
ce3d39e2 IZ |
1256 | |
1257 | A lot of opcodes (this is an elementary operation in the internal perl | |
1258 | stack machine) put an SV* on the stack. However, as an optimization | |
1259 | the corresponding SV is (usually) not recreated each time. The opcodes | |
1260 | reuse specially assigned SVs (I<target>s) which are (as a corollary) | |
1261 | not constantly freed/created. | |
1262 | ||
0a753a76 | 1263 | Each of the targets is created only once (but see |
ce3d39e2 IZ |
1264 | L<Scratchpads and recursion> below), and when an opcode needs to put |
1265 | an integer, a double, or a string on stack, it just sets the | |
1266 | corresponding parts of its I<target> and puts the I<target> on stack. | |
1267 | ||
1268 | The macro to put this target on stack is C<PUSHTARG>, and it is | |
1269 | directly used in some opcodes, as well as indirectly in zillions of | |
1270 | others, which use it via C<(X)PUSH[pni]>. | |
1271 | ||
8ebc5c01 | 1272 | =head2 Scratchpads |
ce3d39e2 | 1273 | |
54310121 | 1274 | The question remains on when the SVs which are I<target>s for opcodes |
5f05dabc | 1275 | are created. The answer is that they are created when the current unit -- |
1276 | a subroutine or a file (for opcodes for statements outside of | |
1277 | subroutines) -- is compiled. During this time a special anonymous Perl | |
ce3d39e2 IZ |
1278 | array is created, which is called a scratchpad for the current |
1279 | unit. | |
1280 | ||
54310121 | 1281 | A scratchpad keeps SVs which are lexicals for the current unit and are |
ce3d39e2 IZ |
1282 | targets for opcodes. One can deduce that an SV lives on a scratchpad |
1283 | by looking on its flags: lexicals have C<SVs_PADMY> set, and | |
1284 | I<target>s have C<SVs_PADTMP> set. | |
1285 | ||
54310121 | 1286 | The correspondence between OPs and I<target>s is not 1-to-1. Different |
1287 | OPs in the compile tree of the unit can use the same target, if this | |
ce3d39e2 IZ |
1288 | would not conflict with the expected life of the temporary. |
1289 | ||
2ae324a7 | 1290 | =head2 Scratchpads and recursion |
ce3d39e2 IZ |
1291 | |
1292 | In fact it is not 100% true that a compiled unit contains a pointer to | |
1293 | the scratchpad AV. In fact it contains a pointer to an AV of | |
1294 | (initially) one element, and this element is the scratchpad AV. Why do | |
1295 | we need an extra level of indirection? | |
1296 | ||
1297 | The answer is B<recursion>, and maybe (sometime soon) B<threads>. Both | |
1298 | these can create several execution pointers going into the same | |
1299 | subroutine. For the subroutine-child not write over the temporaries | |
1300 | for the subroutine-parent (lifespan of which covers the call to the | |
1301 | child), the parent and the child should have different | |
1302 | scratchpads. (I<And> the lexicals should be separate anyway!) | |
1303 | ||
5f05dabc | 1304 | So each subroutine is born with an array of scratchpads (of length 1). |
1305 | On each entry to the subroutine it is checked that the current | |
ce3d39e2 IZ |
1306 | depth of the recursion is not more than the length of this array, and |
1307 | if it is, new scratchpad is created and pushed into the array. | |
1308 | ||
1309 | The I<target>s on this scratchpad are C<undef>s, but they are already | |
1310 | marked with correct flags. | |
1311 | ||
0a753a76 | 1312 | =head1 Compiled code |
1313 | ||
1314 | =head2 Code tree | |
1315 | ||
1316 | Here we describe the internal form your code is converted to by | |
1317 | Perl. Start with a simple example: | |
1318 | ||
1319 | $a = $b + $c; | |
1320 | ||
1321 | This is converted to a tree similar to this one: | |
1322 | ||
1323 | assign-to | |
1324 | / \ | |
1325 | + $a | |
1326 | / \ | |
1327 | $b $c | |
1328 | ||
7b8d334a | 1329 | (but slightly more complicated). This tree reflects the way Perl |
0a753a76 | 1330 | parsed your code, but has nothing to do with the execution order. |
1331 | There is an additional "thread" going through the nodes of the tree | |
1332 | which shows the order of execution of the nodes. In our simplified | |
1333 | example above it looks like: | |
1334 | ||
1335 | $b ---> $c ---> + ---> $a ---> assign-to | |
1336 | ||
1337 | But with the actual compile tree for C<$a = $b + $c> it is different: | |
1338 | some nodes I<optimized away>. As a corollary, though the actual tree | |
1339 | contains more nodes than our simplified example, the execution order | |
1340 | is the same as in our example. | |
1341 | ||
1342 | =head2 Examining the tree | |
1343 | ||
1344 | If you have your perl compiled for debugging (usually done with C<-D | |
1345 | optimize=-g> on C<Configure> command line), you may examine the | |
1346 | compiled tree by specifying C<-Dx> on the Perl command line. The | |
1347 | output takes several lines per node, and for C<$b+$c> it looks like | |
1348 | this: | |
1349 | ||
1350 | 5 TYPE = add ===> 6 | |
1351 | TARG = 1 | |
1352 | FLAGS = (SCALAR,KIDS) | |
1353 | { | |
1354 | TYPE = null ===> (4) | |
1355 | (was rv2sv) | |
1356 | FLAGS = (SCALAR,KIDS) | |
1357 | { | |
1358 | 3 TYPE = gvsv ===> 4 | |
1359 | FLAGS = (SCALAR) | |
1360 | GV = main::b | |
1361 | } | |
1362 | } | |
1363 | { | |
1364 | TYPE = null ===> (5) | |
1365 | (was rv2sv) | |
1366 | FLAGS = (SCALAR,KIDS) | |
1367 | { | |
1368 | 4 TYPE = gvsv ===> 5 | |
1369 | FLAGS = (SCALAR) | |
1370 | GV = main::c | |
1371 | } | |
1372 | } | |
1373 | ||
1374 | This tree has 5 nodes (one per C<TYPE> specifier), only 3 of them are | |
1375 | not optimized away (one per number in the left column). The immediate | |
1376 | children of the given node correspond to C<{}> pairs on the same level | |
1377 | of indentation, thus this listing corresponds to the tree: | |
1378 | ||
1379 | add | |
1380 | / \ | |
1381 | null null | |
1382 | | | | |
1383 | gvsv gvsv | |
1384 | ||
1385 | The execution order is indicated by C<===E<gt>> marks, thus it is C<3 | |
1386 | 4 5 6> (node C<6> is not included into above listing), i.e., | |
1387 | C<gvsv gvsv add whatever>. | |
1388 | ||
1389 | =head2 Compile pass 1: check routines | |
1390 | ||
1391 | The tree is created by the I<pseudo-compiler> while yacc code feeds it | |
1392 | the constructions it recognizes. Since yacc works bottom-up, so does | |
1393 | the first pass of perl compilation. | |
1394 | ||
1395 | What makes this pass interesting for perl developers is that some | |
1396 | optimization may be performed on this pass. This is optimization by | |
1397 | so-called I<check routines>. The correspondence between node names | |
1398 | and corresponding check routines is described in F<opcode.pl> (do not | |
1399 | forget to run C<make regen_headers> if you modify this file). | |
1400 | ||
1401 | A check routine is called when the node is fully constructed except | |
7b8d334a | 1402 | for the execution-order thread. Since at this time there are no |
0a753a76 | 1403 | back-links to the currently constructed node, one can do most any |
1404 | operation to the top-level node, including freeing it and/or creating | |
1405 | new nodes above/below it. | |
1406 | ||
1407 | The check routine returns the node which should be inserted into the | |
1408 | tree (if the top-level node was not modified, check routine returns | |
1409 | its argument). | |
1410 | ||
1411 | By convention, check routines have names C<ck_*>. They are usually | |
1412 | called from C<new*OP> subroutines (or C<convert>) (which in turn are | |
1413 | called from F<perly.y>). | |
1414 | ||
1415 | =head2 Compile pass 1a: constant folding | |
1416 | ||
1417 | Immediately after the check routine is called the returned node is | |
1418 | checked for being compile-time executable. If it is (the value is | |
1419 | judged to be constant) it is immediately executed, and a I<constant> | |
1420 | node with the "return value" of the corresponding subtree is | |
1421 | substituted instead. The subtree is deleted. | |
1422 | ||
1423 | If constant folding was not performed, the execution-order thread is | |
1424 | created. | |
1425 | ||
1426 | =head2 Compile pass 2: context propagation | |
1427 | ||
1428 | When a context for a part of compile tree is known, it is propagated | |
a3cb178b | 1429 | down through the tree. At this time the context can have 5 values |
0a753a76 | 1430 | (instead of 2 for runtime context): void, boolean, scalar, list, and |
1431 | lvalue. In contrast with the pass 1 this pass is processed from top | |
1432 | to bottom: a node's context determines the context for its children. | |
1433 | ||
1434 | Additional context-dependent optimizations are performed at this time. | |
1435 | Since at this moment the compile tree contains back-references (via | |
1436 | "thread" pointers), nodes cannot be free()d now. To allow | |
1437 | optimized-away nodes at this stage, such nodes are null()ified instead | |
1438 | of free()ing (i.e. their type is changed to OP_NULL). | |
1439 | ||
1440 | =head2 Compile pass 3: peephole optimization | |
1441 | ||
1442 | After the compile tree for a subroutine (or for an C<eval> or a file) | |
1443 | is created, an additional pass over the code is performed. This pass | |
1444 | is neither top-down or bottom-up, but in the execution order (with | |
7b8d334a | 1445 | additional complications for conditionals). These optimizations are |
0a753a76 | 1446 | done in the subroutine peep(). Optimizations performed at this stage |
1447 | are subject to the same restrictions as in the pass 2. | |
1448 | ||
1449 | =head1 API LISTING | |
a0d0e21e | 1450 | |
cb1a09d0 AD |
1451 | This is a listing of functions, macros, flags, and variables that may be |
1452 | useful to extension writers or that may be found while reading other | |
1453 | extensions. | |
9cde0e7f GS |
1454 | |
1455 | Note that all Perl API global variables must be referenced with the C<PL_> | |
1456 | prefix. Some macros are provided for compatibility with the older, | |
1457 | unadorned names, but this support will be removed in a future release. | |
1458 | ||
1459 | It is strongly recommended that all Perl API functions that don't begin | |
1460 | with C<perl> be referenced with an explicit C<Perl_> prefix. | |
1461 | ||
e89caa19 GA |
1462 | The sort order of the listing is case insensitive, with any |
1463 | occurrences of '_' ignored for the the purpose of sorting. | |
a0d0e21e | 1464 | |
cb1a09d0 | 1465 | =over 8 |
a0d0e21e | 1466 | |
cb1a09d0 AD |
1467 | =item av_clear |
1468 | ||
0146554f GA |
1469 | Clears an array, making it empty. Does not free the memory used by the |
1470 | array itself. | |
cb1a09d0 | 1471 | |
ef50df4b | 1472 | void av_clear (AV* ar) |
cb1a09d0 AD |
1473 | |
1474 | =item av_extend | |
1475 | ||
1476 | Pre-extend an array. The C<key> is the index to which the array should be | |
1477 | extended. | |
1478 | ||
ef50df4b | 1479 | void av_extend (AV* ar, I32 key) |
cb1a09d0 AD |
1480 | |
1481 | =item av_fetch | |
1482 | ||
1483 | Returns the SV at the specified index in the array. The C<key> is the | |
1484 | index. If C<lval> is set then the fetch will be part of a store. Check | |
1485 | that the return value is non-null before dereferencing it to a C<SV*>. | |
1486 | ||
04343c6d GS |
1487 | See L<Understanding the Magic of Tied Hashes and Arrays> for more |
1488 | information on how to use this function on tied arrays. | |
1489 | ||
ef50df4b | 1490 | SV** av_fetch (AV* ar, I32 key, I32 lval) |
cb1a09d0 | 1491 | |
e89caa19 GA |
1492 | =item AvFILL |
1493 | ||
95906810 | 1494 | Same as C<av_len()>. Deprecated, use C<av_len()> instead. |
e89caa19 | 1495 | |
cb1a09d0 AD |
1496 | =item av_len |
1497 | ||
1498 | Returns the highest index in the array. Returns -1 if the array is empty. | |
1499 | ||
ef50df4b | 1500 | I32 av_len (AV* ar) |
cb1a09d0 AD |
1501 | |
1502 | =item av_make | |
1503 | ||
5fb8527f | 1504 | Creates a new AV and populates it with a list of SVs. The SVs are copied |
1505 | into the array, so they may be freed after the call to av_make. The new AV | |
5f05dabc | 1506 | will have a reference count of 1. |
cb1a09d0 | 1507 | |
ef50df4b | 1508 | AV* av_make (I32 size, SV** svp) |
cb1a09d0 AD |
1509 | |
1510 | =item av_pop | |
1511 | ||
9cde0e7f | 1512 | Pops an SV off the end of the array. Returns C<&PL_sv_undef> if the array is |
cb1a09d0 AD |
1513 | empty. |
1514 | ||
ef50df4b | 1515 | SV* av_pop (AV* ar) |
cb1a09d0 AD |
1516 | |
1517 | =item av_push | |
1518 | ||
5fb8527f | 1519 | Pushes an SV onto the end of the array. The array will grow automatically |
1520 | to accommodate the addition. | |
cb1a09d0 | 1521 | |
ef50df4b | 1522 | void av_push (AV* ar, SV* val) |
cb1a09d0 AD |
1523 | |
1524 | =item av_shift | |
1525 | ||
1526 | Shifts an SV off the beginning of the array. | |
1527 | ||
ef50df4b | 1528 | SV* av_shift (AV* ar) |
cb1a09d0 AD |
1529 | |
1530 | =item av_store | |
1531 | ||
1532 | Stores an SV in an array. The array index is specified as C<key>. The | |
04343c6d GS |
1533 | return value will be NULL if the operation failed or if the value did not |
1534 | need to be actually stored within the array (as in the case of tied arrays). | |
1535 | Otherwise it can be dereferenced to get the original C<SV*>. Note that the | |
1536 | caller is responsible for suitably incrementing the reference count of C<val> | |
1537 | before the call, and decrementing it if the function returned NULL. | |
1538 | ||
1539 | See L<Understanding the Magic of Tied Hashes and Arrays> for more | |
1540 | information on how to use this function on tied arrays. | |
cb1a09d0 | 1541 | |
ef50df4b | 1542 | SV** av_store (AV* ar, I32 key, SV* val) |
cb1a09d0 AD |
1543 | |
1544 | =item av_undef | |
1545 | ||
0146554f | 1546 | Undefines the array. Frees the memory used by the array itself. |
cb1a09d0 | 1547 | |
ef50df4b | 1548 | void av_undef (AV* ar) |
cb1a09d0 AD |
1549 | |
1550 | =item av_unshift | |
1551 | ||
0146554f GA |
1552 | Unshift the given number of C<undef> values onto the beginning of the |
1553 | array. The array will grow automatically to accommodate the addition. | |
1554 | You must then use C<av_store> to assign values to these new elements. | |
cb1a09d0 | 1555 | |
ef50df4b | 1556 | void av_unshift (AV* ar, I32 num) |
cb1a09d0 AD |
1557 | |
1558 | =item CLASS | |
1559 | ||
1560 | Variable which is setup by C<xsubpp> to indicate the class name for a C++ XS | |
5fb8527f | 1561 | constructor. This is always a C<char*>. See C<THIS> and |
1562 | L<perlxs/"Using XS With C++">. | |
cb1a09d0 AD |
1563 | |
1564 | =item Copy | |
1565 | ||
1566 | The XSUB-writer's interface to the C C<memcpy> function. The C<s> is the | |
1567 | source, C<d> is the destination, C<n> is the number of items, and C<t> is | |
0146554f | 1568 | the type. May fail on overlapping copies. See also C<Move>. |
cb1a09d0 | 1569 | |
e89caa19 | 1570 | void Copy( s, d, n, t ) |
cb1a09d0 AD |
1571 | |
1572 | =item croak | |
1573 | ||
1574 | This is the XSUB-writer's interface to Perl's C<die> function. Use this | |
1575 | function the same way you use the C C<printf> function. See C<warn>. | |
1576 | ||
1577 | =item CvSTASH | |
1578 | ||
1579 | Returns the stash of the CV. | |
1580 | ||
e89caa19 | 1581 | HV* CvSTASH( SV* sv ) |
cb1a09d0 | 1582 | |
9cde0e7f | 1583 | =item PL_DBsingle |
cb1a09d0 AD |
1584 | |
1585 | When Perl is run in debugging mode, with the B<-d> switch, this SV is a | |
1586 | boolean which indicates whether subs are being single-stepped. | |
5fb8527f | 1587 | Single-stepping is automatically turned on after every step. This is the C |
9cde0e7f | 1588 | variable which corresponds to Perl's $DB::single variable. See C<PL_DBsub>. |
cb1a09d0 | 1589 | |
9cde0e7f | 1590 | =item PL_DBsub |
cb1a09d0 AD |
1591 | |
1592 | When Perl is run in debugging mode, with the B<-d> switch, this GV contains | |
5fb8527f | 1593 | the SV which holds the name of the sub being debugged. This is the C |
9cde0e7f | 1594 | variable which corresponds to Perl's $DB::sub variable. See C<PL_DBsingle>. |
cb1a09d0 AD |
1595 | The sub name can be found by |
1596 | ||
9cde0e7f | 1597 | SvPV( GvSV( PL_DBsub ), PL_na ) |
cb1a09d0 | 1598 | |
9cde0e7f | 1599 | =item PL_DBtrace |
5fb8527f | 1600 | |
1601 | Trace variable used when Perl is run in debugging mode, with the B<-d> | |
1602 | switch. This is the C variable which corresponds to Perl's $DB::trace | |
9cde0e7f | 1603 | variable. See C<PL_DBsingle>. |
5fb8527f | 1604 | |
cb1a09d0 AD |
1605 | =item dMARK |
1606 | ||
5fb8527f | 1607 | Declare a stack marker variable, C<mark>, for the XSUB. See C<MARK> and |
1608 | C<dORIGMARK>. | |
cb1a09d0 AD |
1609 | |
1610 | =item dORIGMARK | |
1611 | ||
1612 | Saves the original stack mark for the XSUB. See C<ORIGMARK>. | |
1613 | ||
9cde0e7f | 1614 | =item PL_dowarn |
5fb8527f | 1615 | |
1616 | The C variable which corresponds to Perl's $^W warning variable. | |
1617 | ||
cb1a09d0 AD |
1618 | =item dSP |
1619 | ||
924508f0 GS |
1620 | Declares a local copy of perl's stack pointer for the XSUB, available via |
1621 | the C<SP> macro. See C<SP>. | |
cb1a09d0 AD |
1622 | |
1623 | =item dXSARGS | |
1624 | ||
1625 | Sets up stack and mark pointers for an XSUB, calling dSP and dMARK. This is | |
1626 | usually handled automatically by C<xsubpp>. Declares the C<items> variable | |
1627 | to indicate the number of items on the stack. | |
1628 | ||
5fb8527f | 1629 | =item dXSI32 |
1630 | ||
1631 | Sets up the C<ix> variable for an XSUB which has aliases. This is usually | |
1632 | handled automatically by C<xsubpp>. | |
1633 | ||
491527d0 GS |
1634 | =item do_binmode |
1635 | ||
1636 | Switches filehandle to binmode. C<iotype> is what C<IoTYPE(io)> would | |
1637 | contain. | |
1638 | ||
1639 | do_binmode(fp, iotype, TRUE); | |
1640 | ||
cb1a09d0 AD |
1641 | =item ENTER |
1642 | ||
1643 | Opening bracket on a callback. See C<LEAVE> and L<perlcall>. | |
1644 | ||
1645 | ENTER; | |
1646 | ||
1647 | =item EXTEND | |
1648 | ||
1649 | Used to extend the argument stack for an XSUB's return values. | |
1650 | ||
ef50df4b | 1651 | EXTEND( sp, int x ) |
cb1a09d0 | 1652 | |
e89caa19 GA |
1653 | =item fbm_compile |
1654 | ||
1655 | Analyses the string in order to make fast searches on it using fbm_instr() -- | |
1656 | the Boyer-Moore algorithm. | |
1657 | ||
411d5715 | 1658 | void fbm_compile(SV* sv, U32 flags) |
e89caa19 GA |
1659 | |
1660 | =item fbm_instr | |
1661 | ||
1662 | Returns the location of the SV in the string delimited by C<str> and | |
1663 | C<strend>. It returns C<Nullch> if the string can't be found. The | |
1664 | C<sv> does not have to be fbm_compiled, but the search will not be as | |
1665 | fast then. | |
1666 | ||
411d5715 | 1667 | char* fbm_instr(char *str, char *strend, SV *sv, U32 flags) |
e89caa19 | 1668 | |
cb1a09d0 AD |
1669 | =item FREETMPS |
1670 | ||
1671 | Closing bracket for temporaries on a callback. See C<SAVETMPS> and | |
1672 | L<perlcall>. | |
1673 | ||
1674 | FREETMPS; | |
1675 | ||
1676 | =item G_ARRAY | |
1677 | ||
54310121 | 1678 | Used to indicate array context. See C<GIMME_V>, C<GIMME> and L<perlcall>. |
cb1a09d0 AD |
1679 | |
1680 | =item G_DISCARD | |
1681 | ||
1682 | Indicates that arguments returned from a callback should be discarded. See | |
1683 | L<perlcall>. | |
1684 | ||
1685 | =item G_EVAL | |
1686 | ||
1687 | Used to force a Perl C<eval> wrapper around a callback. See L<perlcall>. | |
1688 | ||
1689 | =item GIMME | |
1690 | ||
54310121 | 1691 | A backward-compatible version of C<GIMME_V> which can only return |
1692 | C<G_SCALAR> or C<G_ARRAY>; in a void context, it returns C<G_SCALAR>. | |
1693 | ||
1694 | =item GIMME_V | |
1695 | ||
1696 | The XSUB-writer's equivalent to Perl's C<wantarray>. Returns | |
1697 | C<G_VOID>, C<G_SCALAR> or C<G_ARRAY> for void, scalar or array | |
1698 | context, respectively. | |
cb1a09d0 AD |
1699 | |
1700 | =item G_NOARGS | |
1701 | ||
1702 | Indicates that no arguments are being sent to a callback. See L<perlcall>. | |
1703 | ||
1704 | =item G_SCALAR | |
1705 | ||
54310121 | 1706 | Used to indicate scalar context. See C<GIMME_V>, C<GIMME>, and L<perlcall>. |
1707 | ||
faed5253 JO |
1708 | =item gv_fetchmeth |
1709 | ||
1710 | Returns the glob with the given C<name> and a defined subroutine or | |
9607fc9c | 1711 | C<NULL>. The glob lives in the given C<stash>, or in the stashes |
f86cebdf | 1712 | accessible via @ISA and @UNIVERSAL. |
faed5253 | 1713 | |
9607fc9c | 1714 | The argument C<level> should be either 0 or -1. If C<level==0>, as a |
0a753a76 | 1715 | side-effect creates a glob with the given C<name> in the given |
1716 | C<stash> which in the case of success contains an alias for the | |
1717 | subroutine, and sets up caching info for this glob. Similarly for all | |
1718 | the searched stashes. | |
1719 | ||
9607fc9c | 1720 | This function grants C<"SUPER"> token as a postfix of the stash name. |
1721 | ||
0a753a76 | 1722 | The GV returned from C<gv_fetchmeth> may be a method cache entry, |
1723 | which is not visible to Perl code. So when calling C<perl_call_sv>, | |
1724 | you should not use the GV directly; instead, you should use the | |
1725 | method's CV, which can be obtained from the GV with the C<GvCV> macro. | |
faed5253 | 1726 | |
ef50df4b | 1727 | GV* gv_fetchmeth (HV* stash, char* name, STRLEN len, I32 level) |
faed5253 JO |
1728 | |
1729 | =item gv_fetchmethod | |
1730 | ||
dc848c6f | 1731 | =item gv_fetchmethod_autoload |
1732 | ||
faed5253 | 1733 | Returns the glob which contains the subroutine to call to invoke the |
dc848c6f | 1734 | method on the C<stash>. In fact in the presense of autoloading this may |
1735 | be the glob for "AUTOLOAD". In this case the corresponding variable | |
faed5253 JO |
1736 | $AUTOLOAD is already setup. |
1737 | ||
dc848c6f | 1738 | The third parameter of C<gv_fetchmethod_autoload> determines whether AUTOLOAD |
1739 | lookup is performed if the given method is not present: non-zero means | |
1740 | yes, look for AUTOLOAD; zero means no, don't look for AUTOLOAD. Calling | |
1741 | C<gv_fetchmethod> is equivalent to calling C<gv_fetchmethod_autoload> with a | |
1742 | non-zero C<autoload> parameter. | |
1743 | ||
1744 | These functions grant C<"SUPER"> token as a prefix of the method name. | |
1745 | ||
1746 | Note that if you want to keep the returned glob for a long time, you | |
1747 | need to check for it being "AUTOLOAD", since at the later time the call | |
faed5253 JO |
1748 | may load a different subroutine due to $AUTOLOAD changing its value. |
1749 | Use the glob created via a side effect to do this. | |
1750 | ||
dc848c6f | 1751 | These functions have the same side-effects and as C<gv_fetchmeth> with |
1752 | C<level==0>. C<name> should be writable if contains C<':'> or C<'\''>. | |
0a753a76 | 1753 | The warning against passing the GV returned by C<gv_fetchmeth> to |
dc848c6f | 1754 | C<perl_call_sv> apply equally to these functions. |
faed5253 | 1755 | |
ef50df4b GS |
1756 | GV* gv_fetchmethod (HV* stash, char* name) |
1757 | GV* gv_fetchmethod_autoload (HV* stash, char* name, I32 autoload) | |
faed5253 | 1758 | |
e89caa19 GA |
1759 | =item G_VOID |
1760 | ||
1761 | Used to indicate void context. See C<GIMME_V> and L<perlcall>. | |
1762 | ||
cb1a09d0 AD |
1763 | =item gv_stashpv |
1764 | ||
1765 | Returns a pointer to the stash for a specified package. If C<create> is set | |
1766 | then the package will be created if it does not already exist. If C<create> | |
1767 | is not set and the package does not exist then NULL is returned. | |
1768 | ||
ef50df4b | 1769 | HV* gv_stashpv (char* name, I32 create) |
cb1a09d0 AD |
1770 | |
1771 | =item gv_stashsv | |
1772 | ||
1773 | Returns a pointer to the stash for a specified package. See C<gv_stashpv>. | |
1774 | ||
ef50df4b | 1775 | HV* gv_stashsv (SV* sv, I32 create) |
cb1a09d0 | 1776 | |
e5581bf4 | 1777 | =item GvSV |
cb1a09d0 | 1778 | |
e5581bf4 | 1779 | Return the SV from the GV. |
44a8e56a | 1780 | |
1e422769 | 1781 | =item HEf_SVKEY |
1782 | ||
1783 | This flag, used in the length slot of hash entries and magic | |
1784 | structures, specifies the structure contains a C<SV*> pointer where a | |
1785 | C<char*> pointer is to be expected. (For information only--not to be used). | |
1786 | ||
1e422769 | 1787 | =item HeHASH |
1788 | ||
e89caa19 | 1789 | Returns the computed hash stored in the hash entry. |
1e422769 | 1790 | |
e89caa19 | 1791 | U32 HeHASH(HE* he) |
1e422769 | 1792 | |
1793 | =item HeKEY | |
1794 | ||
1795 | Returns the actual pointer stored in the key slot of the hash entry. | |
1796 | The pointer may be either C<char*> or C<SV*>, depending on the value of | |
1797 | C<HeKLEN()>. Can be assigned to. The C<HePV()> or C<HeSVKEY()> macros | |
1798 | are usually preferable for finding the value of a key. | |
1799 | ||
e89caa19 | 1800 | char* HeKEY(HE* he) |
1e422769 | 1801 | |
1802 | =item HeKLEN | |
1803 | ||
1804 | If this is negative, and amounts to C<HEf_SVKEY>, it indicates the entry | |
1805 | holds an C<SV*> key. Otherwise, holds the actual length of the key. | |
1806 | Can be assigned to. The C<HePV()> macro is usually preferable for finding | |
1807 | key lengths. | |
1808 | ||
e89caa19 | 1809 | int HeKLEN(HE* he) |
1e422769 | 1810 | |
1811 | =item HePV | |
1812 | ||
1813 | Returns the key slot of the hash entry as a C<char*> value, doing any | |
1814 | necessary dereferencing of possibly C<SV*> keys. The length of | |
1815 | the string is placed in C<len> (this is a macro, so do I<not> use | |
1816 | C<&len>). If you do not care about what the length of the key is, | |
9cde0e7f | 1817 | you may use the global variable C<PL_na>. Remember though, that hash |
1e422769 | 1818 | keys in perl are free to contain embedded nulls, so using C<strlen()> |
1819 | or similar is not a good way to find the length of hash keys. | |
1820 | This is very similar to the C<SvPV()> macro described elsewhere in | |
1821 | this document. | |
1822 | ||
e89caa19 | 1823 | char* HePV(HE* he, STRLEN len) |
1e422769 | 1824 | |
1825 | =item HeSVKEY | |
1826 | ||
1827 | Returns the key as an C<SV*>, or C<Nullsv> if the hash entry | |
1828 | does not contain an C<SV*> key. | |
1829 | ||
1830 | HeSVKEY(HE* he) | |
1831 | ||
1832 | =item HeSVKEY_force | |
1833 | ||
1834 | Returns the key as an C<SV*>. Will create and return a temporary | |
1835 | mortal C<SV*> if the hash entry contains only a C<char*> key. | |
1836 | ||
1837 | HeSVKEY_force(HE* he) | |
1838 | ||
1839 | =item HeSVKEY_set | |
1840 | ||
1841 | Sets the key to a given C<SV*>, taking care to set the appropriate flags | |
1842 | to indicate the presence of an C<SV*> key, and returns the same C<SV*>. | |
1843 | ||
1844 | HeSVKEY_set(HE* he, SV* sv) | |
1845 | ||
1846 | =item HeVAL | |
1847 | ||
1848 | Returns the value slot (type C<SV*>) stored in the hash entry. | |
1849 | ||
1850 | HeVAL(HE* he) | |
1851 | ||
cb1a09d0 AD |
1852 | =item hv_clear |
1853 | ||
1854 | Clears a hash, making it empty. | |
1855 | ||
ef50df4b | 1856 | void hv_clear (HV* tb) |
cb1a09d0 | 1857 | |
68dc0745 | 1858 | =item hv_delayfree_ent |
1859 | ||
1860 | Releases a hash entry, such as while iterating though the hash, but | |
1861 | delays actual freeing of key and value until the end of the current | |
1862 | statement (or thereabouts) with C<sv_2mortal>. See C<hv_iternext> | |
1863 | and C<hv_free_ent>. | |
1864 | ||
ef50df4b | 1865 | void hv_delayfree_ent (HV* hv, HE* entry) |
68dc0745 | 1866 | |
cb1a09d0 AD |
1867 | =item hv_delete |
1868 | ||
1869 | Deletes a key/value pair in the hash. The value SV is removed from the hash | |
5fb8527f | 1870 | and returned to the caller. The C<klen> is the length of the key. The |
04343c6d | 1871 | C<flags> value will normally be zero; if set to G_DISCARD then NULL will be |
cb1a09d0 AD |
1872 | returned. |
1873 | ||
ef50df4b | 1874 | SV* hv_delete (HV* tb, char* key, U32 klen, I32 flags) |
cb1a09d0 | 1875 | |
1e422769 | 1876 | =item hv_delete_ent |
1877 | ||
1878 | Deletes a key/value pair in the hash. The value SV is removed from the hash | |
1879 | and returned to the caller. The C<flags> value will normally be zero; if set | |
04343c6d | 1880 | to G_DISCARD then NULL will be returned. C<hash> can be a valid precomputed |
1e422769 | 1881 | hash value, or 0 to ask for it to be computed. |
1882 | ||
ef50df4b | 1883 | SV* hv_delete_ent (HV* tb, SV* key, I32 flags, U32 hash) |
1e422769 | 1884 | |
cb1a09d0 AD |
1885 | =item hv_exists |
1886 | ||
1887 | Returns a boolean indicating whether the specified hash key exists. The | |
5fb8527f | 1888 | C<klen> is the length of the key. |
cb1a09d0 | 1889 | |
ef50df4b | 1890 | bool hv_exists (HV* tb, char* key, U32 klen) |
cb1a09d0 | 1891 | |
1e422769 | 1892 | =item hv_exists_ent |
1893 | ||
1894 | Returns a boolean indicating whether the specified hash key exists. C<hash> | |
54310121 | 1895 | can be a valid precomputed hash value, or 0 to ask for it to be computed. |
1e422769 | 1896 | |
ef50df4b | 1897 | bool hv_exists_ent (HV* tb, SV* key, U32 hash) |
1e422769 | 1898 | |
cb1a09d0 AD |
1899 | =item hv_fetch |
1900 | ||
1901 | Returns the SV which corresponds to the specified key in the hash. The | |
5fb8527f | 1902 | C<klen> is the length of the key. If C<lval> is set then the fetch will be |
cb1a09d0 AD |
1903 | part of a store. Check that the return value is non-null before |
1904 | dereferencing it to a C<SV*>. | |
1905 | ||
04343c6d GS |
1906 | See L<Understanding the Magic of Tied Hashes and Arrays> for more |
1907 | information on how to use this function on tied hashes. | |
1908 | ||
ef50df4b | 1909 | SV** hv_fetch (HV* tb, char* key, U32 klen, I32 lval) |
cb1a09d0 | 1910 | |
1e422769 | 1911 | =item hv_fetch_ent |
1912 | ||
1913 | Returns the hash entry which corresponds to the specified key in the hash. | |
54310121 | 1914 | C<hash> must be a valid precomputed hash number for the given C<key>, or |
1e422769 | 1915 | 0 if you want the function to compute it. IF C<lval> is set then the |
1916 | fetch will be part of a store. Make sure the return value is non-null | |
1917 | before accessing it. The return value when C<tb> is a tied hash | |
1918 | is a pointer to a static location, so be sure to make a copy of the | |
1919 | structure if you need to store it somewhere. | |
1920 | ||
04343c6d GS |
1921 | See L<Understanding the Magic of Tied Hashes and Arrays> for more |
1922 | information on how to use this function on tied hashes. | |
1923 | ||
ef50df4b | 1924 | HE* hv_fetch_ent (HV* tb, SV* key, I32 lval, U32 hash) |
1e422769 | 1925 | |
68dc0745 | 1926 | =item hv_free_ent |
1927 | ||
1928 | Releases a hash entry, such as while iterating though the hash. See | |
1929 | C<hv_iternext> and C<hv_delayfree_ent>. | |
1930 | ||
ef50df4b | 1931 | void hv_free_ent (HV* hv, HE* entry) |
68dc0745 | 1932 | |
cb1a09d0 AD |
1933 | =item hv_iterinit |
1934 | ||
1935 | Prepares a starting point to traverse a hash table. | |
1936 | ||
ef50df4b | 1937 | I32 hv_iterinit (HV* tb) |
cb1a09d0 | 1938 | |
c6601927 SI |
1939 | Returns the number of keys in the hash (i.e. the same as C<HvKEYS(tb)>). |
1940 | The return value is currently only meaningful for hashes without tie | |
1941 | magic. | |
1942 | ||
1943 | NOTE: Before version 5.004_65, C<hv_iterinit> used to return the number | |
1944 | of hash buckets that happen to be in use. If you still need that | |
1945 | esoteric value, you can get it through the macro C<HvFILL(tb)>. | |
fb73857a | 1946 | |
cb1a09d0 AD |
1947 | =item hv_iterkey |
1948 | ||
1949 | Returns the key from the current position of the hash iterator. See | |
1950 | C<hv_iterinit>. | |
1951 | ||
ef50df4b | 1952 | char* hv_iterkey (HE* entry, I32* retlen) |
cb1a09d0 | 1953 | |
1e422769 | 1954 | =item hv_iterkeysv |
3fe9a6f1 | 1955 | |
1e422769 | 1956 | Returns the key as an C<SV*> from the current position of the hash |
1957 | iterator. The return value will always be a mortal copy of the | |
1958 | key. Also see C<hv_iterinit>. | |
1959 | ||
ef50df4b | 1960 | SV* hv_iterkeysv (HE* entry) |
1e422769 | 1961 | |
cb1a09d0 AD |
1962 | =item hv_iternext |
1963 | ||
1964 | Returns entries from a hash iterator. See C<hv_iterinit>. | |
1965 | ||
ef50df4b | 1966 | HE* hv_iternext (HV* tb) |
cb1a09d0 AD |
1967 | |
1968 | =item hv_iternextsv | |
1969 | ||
1970 | Performs an C<hv_iternext>, C<hv_iterkey>, and C<hv_iterval> in one | |
1971 | operation. | |
1972 | ||
e89caa19 | 1973 | SV* hv_iternextsv (HV* hv, char** key, I32* retlen) |
cb1a09d0 AD |
1974 | |
1975 | =item hv_iterval | |
1976 | ||
1977 | Returns the value from the current position of the hash iterator. See | |
1978 | C<hv_iterkey>. | |
1979 | ||
ef50df4b | 1980 | SV* hv_iterval (HV* tb, HE* entry) |
cb1a09d0 AD |
1981 | |
1982 | =item hv_magic | |
1983 | ||
1984 | Adds magic to a hash. See C<sv_magic>. | |
1985 | ||
ef50df4b | 1986 | void hv_magic (HV* hv, GV* gv, int how) |
cb1a09d0 AD |
1987 | |
1988 | =item HvNAME | |
1989 | ||
1990 | Returns the package name of a stash. See C<SvSTASH>, C<CvSTASH>. | |
1991 | ||
e89caa19 | 1992 | char* HvNAME (HV* stash) |
cb1a09d0 AD |
1993 | |
1994 | =item hv_store | |
1995 | ||
1996 | Stores an SV in a hash. The hash key is specified as C<key> and C<klen> is | |
54310121 | 1997 | the length of the key. The C<hash> parameter is the precomputed hash |
cb1a09d0 | 1998 | value; if it is zero then Perl will compute it. The return value will be |
04343c6d GS |
1999 | NULL if the operation failed or if the value did not need to be actually |
2000 | stored within the hash (as in the case of tied hashes). Otherwise it can | |
2001 | be dereferenced to get the original C<SV*>. Note that the caller is | |
2002 | responsible for suitably incrementing the reference count of C<val> | |
2003 | before the call, and decrementing it if the function returned NULL. | |
2004 | ||
2005 | See L<Understanding the Magic of Tied Hashes and Arrays> for more | |
2006 | information on how to use this function on tied hashes. | |
cb1a09d0 | 2007 | |
ef50df4b | 2008 | SV** hv_store (HV* tb, char* key, U32 klen, SV* val, U32 hash) |
cb1a09d0 | 2009 | |
1e422769 | 2010 | =item hv_store_ent |
2011 | ||
2012 | Stores C<val> in a hash. The hash key is specified as C<key>. The C<hash> | |
54310121 | 2013 | parameter is the precomputed hash value; if it is zero then Perl will |
1e422769 | 2014 | compute it. The return value is the new hash entry so created. It will be |
04343c6d GS |
2015 | NULL if the operation failed or if the value did not need to be actually |
2016 | stored within the hash (as in the case of tied hashes). Otherwise the | |
2017 | contents of the return value can be accessed using the C<He???> macros | |
2018 | described here. Note that the caller is responsible for suitably | |
2019 | incrementing the reference count of C<val> before the call, and decrementing | |
2020 | it if the function returned NULL. | |
2021 | ||
2022 | See L<Understanding the Magic of Tied Hashes and Arrays> for more | |
2023 | information on how to use this function on tied hashes. | |
1e422769 | 2024 | |
ef50df4b | 2025 | HE* hv_store_ent (HV* tb, SV* key, SV* val, U32 hash) |
1e422769 | 2026 | |
cb1a09d0 AD |
2027 | =item hv_undef |
2028 | ||
2029 | Undefines the hash. | |
2030 | ||
ef50df4b | 2031 | void hv_undef (HV* tb) |
cb1a09d0 AD |
2032 | |
2033 | =item isALNUM | |
2034 | ||
2035 | Returns a boolean indicating whether the C C<char> is an ascii alphanumeric | |
5f05dabc | 2036 | character or digit. |
cb1a09d0 | 2037 | |
e89caa19 | 2038 | int isALNUM (char c) |
cb1a09d0 AD |
2039 | |
2040 | =item isALPHA | |
2041 | ||
5fb8527f | 2042 | Returns a boolean indicating whether the C C<char> is an ascii alphabetic |
cb1a09d0 AD |
2043 | character. |
2044 | ||
e89caa19 | 2045 | int isALPHA (char c) |
cb1a09d0 AD |
2046 | |
2047 | =item isDIGIT | |
2048 | ||
2049 | Returns a boolean indicating whether the C C<char> is an ascii digit. | |
2050 | ||
e89caa19 | 2051 | int isDIGIT (char c) |
cb1a09d0 AD |
2052 | |
2053 | =item isLOWER | |
2054 | ||
2055 | Returns a boolean indicating whether the C C<char> is a lowercase character. | |
2056 | ||
e89caa19 | 2057 | int isLOWER (char c) |
cb1a09d0 AD |
2058 | |
2059 | =item isSPACE | |
2060 | ||
2061 | Returns a boolean indicating whether the C C<char> is whitespace. | |
2062 | ||
e89caa19 | 2063 | int isSPACE (char c) |
cb1a09d0 AD |
2064 | |
2065 | =item isUPPER | |
2066 | ||
2067 | Returns a boolean indicating whether the C C<char> is an uppercase character. | |
2068 | ||
e89caa19 | 2069 | int isUPPER (char c) |
cb1a09d0 AD |
2070 | |
2071 | =item items | |
2072 | ||
2073 | Variable which is setup by C<xsubpp> to indicate the number of items on the | |
5fb8527f | 2074 | stack. See L<perlxs/"Variable-length Parameter Lists">. |
2075 | ||
2076 | =item ix | |
2077 | ||
2078 | Variable which is setup by C<xsubpp> to indicate which of an XSUB's aliases | |
2079 | was used to invoke it. See L<perlxs/"The ALIAS: Keyword">. | |
cb1a09d0 AD |
2080 | |
2081 | =item LEAVE | |
2082 | ||
2083 | Closing bracket on a callback. See C<ENTER> and L<perlcall>. | |
2084 | ||
2085 | LEAVE; | |
2086 | ||
e89caa19 GA |
2087 | =item looks_like_number |
2088 | ||
2089 | Test if an the content of an SV looks like a number (or is a number). | |
2090 | ||
2091 | int looks_like_number(SV*) | |
2092 | ||
2093 | ||
cb1a09d0 AD |
2094 | =item MARK |
2095 | ||
5fb8527f | 2096 | Stack marker variable for the XSUB. See C<dMARK>. |
cb1a09d0 AD |
2097 | |
2098 | =item mg_clear | |
2099 | ||
2100 | Clear something magical that the SV represents. See C<sv_magic>. | |
2101 | ||
ef50df4b | 2102 | int mg_clear (SV* sv) |
cb1a09d0 AD |
2103 | |
2104 | =item mg_copy | |
2105 | ||
2106 | Copies the magic from one SV to another. See C<sv_magic>. | |
2107 | ||
ef50df4b | 2108 | int mg_copy (SV *, SV *, char *, STRLEN) |
cb1a09d0 AD |
2109 | |
2110 | =item mg_find | |
2111 | ||
2112 | Finds the magic pointer for type matching the SV. See C<sv_magic>. | |
2113 | ||
ef50df4b | 2114 | MAGIC* mg_find (SV* sv, int type) |
cb1a09d0 AD |
2115 | |
2116 | =item mg_free | |
2117 | ||
2118 | Free any magic storage used by the SV. See C<sv_magic>. | |
2119 | ||
ef50df4b | 2120 | int mg_free (SV* sv) |
cb1a09d0 AD |
2121 | |
2122 | =item mg_get | |
2123 | ||
2124 | Do magic after a value is retrieved from the SV. See C<sv_magic>. | |
2125 | ||
ef50df4b | 2126 | int mg_get (SV* sv) |
cb1a09d0 AD |
2127 | |
2128 | =item mg_len | |
2129 | ||
2130 | Report on the SV's length. See C<sv_magic>. | |
2131 | ||
ef50df4b | 2132 | U32 mg_len (SV* sv) |
cb1a09d0 AD |
2133 | |
2134 | =item mg_magical | |
2135 | ||
2136 | Turns on the magical status of an SV. See C<sv_magic>. | |
2137 | ||
ef50df4b | 2138 | void mg_magical (SV* sv) |
cb1a09d0 AD |
2139 | |
2140 | =item mg_set | |
2141 | ||
2142 | Do magic after a value is assigned to the SV. See C<sv_magic>. | |
2143 | ||
ef50df4b | 2144 | int mg_set (SV* sv) |
cb1a09d0 AD |
2145 | |
2146 | =item Move | |
2147 | ||
2148 | The XSUB-writer's interface to the C C<memmove> function. The C<s> is the | |
2149 | source, C<d> is the destination, C<n> is the number of items, and C<t> is | |
0146554f | 2150 | the type. Can do overlapping moves. See also C<Copy>. |
cb1a09d0 | 2151 | |
e89caa19 | 2152 | void Move( s, d, n, t ) |
cb1a09d0 | 2153 | |
9cde0e7f | 2154 | =item PL_na |
cb1a09d0 AD |
2155 | |
2156 | A variable which may be used with C<SvPV> to tell Perl to calculate the | |
2157 | string length. | |
2158 | ||
2159 | =item New | |
2160 | ||
2161 | The XSUB-writer's interface to the C C<malloc> function. | |
2162 | ||
e89caa19 | 2163 | void* New( x, void *ptr, int size, type ) |
cb1a09d0 AD |
2164 | |
2165 | =item newAV | |
2166 | ||
5f05dabc | 2167 | Creates a new AV. The reference count is set to 1. |
cb1a09d0 | 2168 | |
ef50df4b | 2169 | AV* newAV (void) |
cb1a09d0 | 2170 | |
e89caa19 GA |
2171 | =item Newc |
2172 | ||
2173 | The XSUB-writer's interface to the C C<malloc> function, with cast. | |
2174 | ||
2175 | void* Newc( x, void *ptr, int size, type, cast ) | |
2176 | ||
5476c433 JD |
2177 | =item newCONSTSUB |
2178 | ||
2179 | Creates a constant sub equivalent to Perl C<sub FOO () { 123 }> | |
2180 | which is eligible for inlining at compile-time. | |
2181 | ||
2182 | void newCONSTSUB(HV* stash, char* name, SV* sv) | |
2183 | ||
cb1a09d0 AD |
2184 | =item newHV |
2185 | ||
5f05dabc | 2186 | Creates a new HV. The reference count is set to 1. |
cb1a09d0 | 2187 | |
ef50df4b | 2188 | HV* newHV (void) |
cb1a09d0 | 2189 | |
5f05dabc | 2190 | =item newRV_inc |
cb1a09d0 | 2191 | |
5f05dabc | 2192 | Creates an RV wrapper for an SV. The reference count for the original SV is |
cb1a09d0 AD |
2193 | incremented. |
2194 | ||
ef50df4b | 2195 | SV* newRV_inc (SV* ref) |
5f05dabc | 2196 | |
2197 | For historical reasons, "newRV" is a synonym for "newRV_inc". | |
2198 | ||
2199 | =item newRV_noinc | |
2200 | ||
2201 | Creates an RV wrapper for an SV. The reference count for the original | |
2202 | SV is B<not> incremented. | |
2203 | ||
ef50df4b | 2204 | SV* newRV_noinc (SV* ref) |
cb1a09d0 | 2205 | |
8c52afec | 2206 | =item NEWSV |
cb1a09d0 | 2207 | |
e89caa19 GA |
2208 | Creates a new SV. A non-zero C<len> parameter indicates the number of |
2209 | bytes of preallocated string space the SV should have. An extra byte | |
2210 | for a tailing NUL is also reserved. (SvPOK is not set for the SV even | |
2211 | if string space is allocated.) The reference count for the new SV is | |
2212 | set to 1. C<id> is an integer id between 0 and 1299 (used to identify | |
2213 | leaks). | |
cb1a09d0 | 2214 | |
ef50df4b | 2215 | SV* NEWSV (int id, STRLEN len) |
cb1a09d0 AD |
2216 | |
2217 | =item newSViv | |
2218 | ||
07fa94a1 JO |
2219 | Creates a new SV and copies an integer into it. The reference count for the |
2220 | SV is set to 1. | |
cb1a09d0 | 2221 | |
ef50df4b | 2222 | SV* newSViv (IV i) |
cb1a09d0 AD |
2223 | |
2224 | =item newSVnv | |
2225 | ||
07fa94a1 JO |
2226 | Creates a new SV and copies a double into it. The reference count for the |
2227 | SV is set to 1. | |
cb1a09d0 | 2228 | |
ef50df4b | 2229 | SV* newSVnv (NV i) |
cb1a09d0 AD |
2230 | |
2231 | =item newSVpv | |
2232 | ||
07fa94a1 JO |
2233 | Creates a new SV and copies a string into it. The reference count for the |
2234 | SV is set to 1. If C<len> is zero then Perl will compute the length. | |
cb1a09d0 | 2235 | |
ef50df4b | 2236 | SV* newSVpv (char* s, STRLEN len) |
cb1a09d0 | 2237 | |
e89caa19 GA |
2238 | =item newSVpvf |
2239 | ||
2240 | Creates a new SV an initialize it with the string formatted like | |
2241 | C<sprintf>. | |
2242 | ||
2243 | SV* newSVpvf(const char* pat, ...); | |
2244 | ||
9da1e3b5 MUN |
2245 | =item newSVpvn |
2246 | ||
2247 | Creates a new SV and copies a string into it. The reference count for the | |
2248 | SV is set to 1. If C<len> is zero then Perl will create a zero length | |
2249 | string. | |
2250 | ||
ef50df4b | 2251 | SV* newSVpvn (char* s, STRLEN len) |
9da1e3b5 | 2252 | |
cb1a09d0 AD |
2253 | =item newSVrv |
2254 | ||
2255 | Creates a new SV for the RV, C<rv>, to point to. If C<rv> is not an RV then | |
5fb8527f | 2256 | it will be upgraded to one. If C<classname> is non-null then the new SV will |
cb1a09d0 | 2257 | be blessed in the specified package. The new SV is returned and its |
5f05dabc | 2258 | reference count is 1. |
8ebc5c01 | 2259 | |
ef50df4b | 2260 | SV* newSVrv (SV* rv, char* classname) |
cb1a09d0 AD |
2261 | |
2262 | =item newSVsv | |
2263 | ||
5fb8527f | 2264 | Creates a new SV which is an exact duplicate of the original SV. |
cb1a09d0 | 2265 | |
ef50df4b | 2266 | SV* newSVsv (SV* old) |
cb1a09d0 AD |
2267 | |
2268 | =item newXS | |
2269 | ||
2270 | Used by C<xsubpp> to hook up XSUBs as Perl subs. | |
2271 | ||
2272 | =item newXSproto | |
2273 | ||
2274 | Used by C<xsubpp> to hook up XSUBs as Perl subs. Adds Perl prototypes to | |
2275 | the subs. | |
2276 | ||
e89caa19 GA |
2277 | =item Newz |
2278 | ||
2279 | The XSUB-writer's interface to the C C<malloc> function. The allocated | |
2280 | memory is zeroed with C<memzero>. | |
2281 | ||
2282 | void* Newz( x, void *ptr, int size, type ) | |
2283 | ||
cb1a09d0 AD |
2284 | =item Nullav |
2285 | ||
2286 | Null AV pointer. | |
2287 | ||
2288 | =item Nullch | |
2289 | ||
2290 | Null character pointer. | |
2291 | ||
2292 | =item Nullcv | |
2293 | ||
2294 | Null CV pointer. | |
2295 | ||
2296 | =item Nullhv | |
2297 | ||
2298 | Null HV pointer. | |
2299 | ||
2300 | =item Nullsv | |
2301 | ||
2302 | Null SV pointer. | |
2303 | ||
2304 | =item ORIGMARK | |
2305 | ||
2306 | The original stack mark for the XSUB. See C<dORIGMARK>. | |
2307 | ||
2308 | =item perl_alloc | |
2309 | ||
2310 | Allocates a new Perl interpreter. See L<perlembed>. | |
2311 | ||
2312 | =item perl_call_argv | |
2313 | ||
2314 | Performs a callback to the specified Perl sub. See L<perlcall>. | |
2315 | ||
ef50df4b | 2316 | I32 perl_call_argv (char* subname, I32 flags, char** argv) |
cb1a09d0 AD |
2317 | |
2318 | =item perl_call_method | |
2319 | ||
2320 | Performs a callback to the specified Perl method. The blessed object must | |
2321 | be on the stack. See L<perlcall>. | |
2322 | ||
ef50df4b | 2323 | I32 perl_call_method (char* methname, I32 flags) |
cb1a09d0 AD |
2324 | |
2325 | =item perl_call_pv | |
2326 | ||
2327 | Performs a callback to the specified Perl sub. See L<perlcall>. | |
2328 | ||
ef50df4b | 2329 | I32 perl_call_pv (char* subname, I32 flags) |
cb1a09d0 AD |
2330 | |
2331 | =item perl_call_sv | |
2332 | ||
2333 | Performs a callback to the Perl sub whose name is in the SV. See | |
2334 | L<perlcall>. | |
2335 | ||
ef50df4b | 2336 | I32 perl_call_sv (SV* sv, I32 flags) |
cb1a09d0 AD |
2337 | |
2338 | =item perl_construct | |
2339 | ||
2340 | Initializes a new Perl interpreter. See L<perlembed>. | |
2341 | ||
2342 | =item perl_destruct | |
2343 | ||
2344 | Shuts down a Perl interpreter. See L<perlembed>. | |
2345 | ||
2346 | =item perl_eval_sv | |
2347 | ||
2348 | Tells Perl to C<eval> the string in the SV. | |
2349 | ||
ef50df4b | 2350 | I32 perl_eval_sv (SV* sv, I32 flags) |
cb1a09d0 | 2351 | |
137443ea | 2352 | =item perl_eval_pv |
2353 | ||
2354 | Tells Perl to C<eval> the given string and return an SV* result. | |
2355 | ||
ef50df4b | 2356 | SV* perl_eval_pv (char* p, I32 croak_on_error) |
137443ea | 2357 | |
cb1a09d0 AD |
2358 | =item perl_free |
2359 | ||
2360 | Releases a Perl interpreter. See L<perlembed>. | |
2361 | ||
2362 | =item perl_get_av | |
2363 | ||
2364 | Returns the AV of the specified Perl array. If C<create> is set and the | |
2365 | Perl variable does not exist then it will be created. If C<create> is not | |
04343c6d | 2366 | set and the variable does not exist then NULL is returned. |
cb1a09d0 | 2367 | |
ef50df4b | 2368 | AV* perl_get_av (char* name, I32 create) |
cb1a09d0 AD |
2369 | |
2370 | =item perl_get_cv | |
2371 | ||
2372 | Returns the CV of the specified Perl sub. If C<create> is set and the Perl | |
2373 | variable does not exist then it will be created. If C<create> is not | |
04343c6d | 2374 | set and the variable does not exist then NULL is returned. |
cb1a09d0 | 2375 | |
ef50df4b | 2376 | CV* perl_get_cv (char* name, I32 create) |
cb1a09d0 AD |
2377 | |
2378 | =item perl_get_hv | |
2379 | ||
2380 | Returns the HV of the specified Perl hash. If C<create> is set and the Perl | |
2381 | variable does not exist then it will be created. If C<create> is not | |
04343c6d | 2382 | set and the variable does not exist then NULL is returned. |
cb1a09d0 | 2383 | |
ef50df4b | 2384 | HV* perl_get_hv (char* name, I32 create) |
cb1a09d0 AD |
2385 | |
2386 | =item perl_get_sv | |
2387 | ||
2388 | Returns the SV of the specified Perl scalar. If C<create> is set and the | |
2389 | Perl variable does not exist then it will be created. If C<create> is not | |
04343c6d | 2390 | set and the variable does not exist then NULL is returned. |
cb1a09d0 | 2391 | |
ef50df4b | 2392 | SV* perl_get_sv (char* name, I32 create) |
cb1a09d0 AD |
2393 | |
2394 | =item perl_parse | |
2395 | ||
2396 | Tells a Perl interpreter to parse a Perl script. See L<perlembed>. | |
2397 | ||
2398 | =item perl_require_pv | |
2399 | ||
2400 | Tells Perl to C<require> a module. | |
2401 | ||
ef50df4b | 2402 | void perl_require_pv (char* pv) |
cb1a09d0 AD |
2403 | |
2404 | =item perl_run | |
2405 | ||
2406 | Tells a Perl interpreter to run. See L<perlembed>. | |
2407 | ||
2408 | =item POPi | |
2409 | ||
2410 | Pops an integer off the stack. | |
2411 | ||
e89caa19 | 2412 | int POPi() |
cb1a09d0 AD |
2413 | |
2414 | =item POPl | |
2415 | ||
2416 | Pops a long off the stack. | |
2417 | ||
e89caa19 | 2418 | long POPl() |
cb1a09d0 AD |
2419 | |
2420 | =item POPp | |
2421 | ||
2422 | Pops a string off the stack. | |
2423 | ||
e89caa19 | 2424 | char* POPp() |
cb1a09d0 AD |
2425 | |
2426 | =item POPn | |
2427 | ||
2428 | Pops a double off the stack. | |
2429 | ||
e89caa19 | 2430 | double POPn() |
cb1a09d0 AD |
2431 | |
2432 | =item POPs | |
2433 | ||
2434 | Pops an SV off the stack. | |
2435 | ||
e89caa19 | 2436 | SV* POPs() |
cb1a09d0 AD |
2437 | |
2438 | =item PUSHMARK | |
2439 | ||
2440 | Opening bracket for arguments on a callback. See C<PUTBACK> and L<perlcall>. | |
2441 | ||
2442 | PUSHMARK(p) | |
2443 | ||
2444 | =item PUSHi | |
2445 | ||
2446 | Push an integer onto the stack. The stack must have room for this element. | |
189b2af5 | 2447 | Handles 'set' magic. See C<XPUSHi>. |
cb1a09d0 | 2448 | |
e89caa19 | 2449 | void PUSHi(int d) |
cb1a09d0 AD |
2450 | |
2451 | =item PUSHn | |
2452 | ||
2453 | Push a double onto the stack. The stack must have room for this element. | |
189b2af5 | 2454 | Handles 'set' magic. See C<XPUSHn>. |
cb1a09d0 | 2455 | |
e89caa19 | 2456 | void PUSHn(double d) |
cb1a09d0 AD |
2457 | |
2458 | =item PUSHp | |
2459 | ||
2460 | Push a string onto the stack. The stack must have room for this element. | |
189b2af5 GS |
2461 | The C<len> indicates the length of the string. Handles 'set' magic. See |
2462 | C<XPUSHp>. | |
cb1a09d0 | 2463 | |
e89caa19 | 2464 | void PUSHp(char *c, int len ) |
cb1a09d0 AD |
2465 | |
2466 | =item PUSHs | |
2467 | ||
189b2af5 GS |
2468 | Push an SV onto the stack. The stack must have room for this element. Does |
2469 | not handle 'set' magic. See C<XPUSHs>. | |
cb1a09d0 | 2470 | |
e89caa19 GA |
2471 | void PUSHs(sv) |
2472 | ||
2473 | =item PUSHu | |
2474 | ||
2475 | Push an unsigned integer onto the stack. The stack must have room for | |
2476 | this element. See C<XPUSHu>. | |
2477 | ||
2478 | void PUSHu(unsigned int d) | |
2479 | ||
cb1a09d0 AD |
2480 | |
2481 | =item PUTBACK | |
2482 | ||
2483 | Closing bracket for XSUB arguments. This is usually handled by C<xsubpp>. | |
2484 | See C<PUSHMARK> and L<perlcall> for other uses. | |
2485 | ||
2486 | PUTBACK; | |
2487 | ||
2488 | =item Renew | |
2489 | ||
2490 | The XSUB-writer's interface to the C C<realloc> function. | |
2491 | ||
e89caa19 | 2492 | void* Renew( void *ptr, int size, type ) |
cb1a09d0 AD |
2493 | |
2494 | =item Renewc | |
2495 | ||
2496 | The XSUB-writer's interface to the C C<realloc> function, with cast. | |
2497 | ||
e89caa19 | 2498 | void* Renewc( void *ptr, int size, type, cast ) |
cb1a09d0 AD |
2499 | |
2500 | =item RETVAL | |
2501 | ||
2502 | Variable which is setup by C<xsubpp> to hold the return value for an XSUB. | |
5fb8527f | 2503 | This is always the proper type for the XSUB. |
2504 | See L<perlxs/"The RETVAL Variable">. | |
cb1a09d0 AD |
2505 | |
2506 | =item safefree | |
2507 | ||
2508 | The XSUB-writer's interface to the C C<free> function. | |
2509 | ||
2510 | =item safemalloc | |
2511 | ||
2512 | The XSUB-writer's interface to the C C<malloc> function. | |
2513 | ||
2514 | =item saferealloc | |
2515 | ||
2516 | The XSUB-writer's interface to the C C<realloc> function. | |
2517 | ||
2518 | =item savepv | |
2519 | ||
2520 | Copy a string to a safe spot. This does not use an SV. | |
2521 | ||
ef50df4b | 2522 | char* savepv (char* sv) |
cb1a09d0 AD |
2523 | |
2524 | =item savepvn | |
2525 | ||
2526 | Copy a string to a safe spot. The C<len> indicates number of bytes to | |
2527 | copy. This does not use an SV. | |
2528 | ||
ef50df4b | 2529 | char* savepvn (char* sv, I32 len) |
cb1a09d0 AD |
2530 | |
2531 | =item SAVETMPS | |
2532 | ||
2533 | Opening bracket for temporaries on a callback. See C<FREETMPS> and | |
2534 | L<perlcall>. | |
2535 | ||
2536 | SAVETMPS; | |
2537 | ||
2538 | =item SP | |
2539 | ||
2540 | Stack pointer. This is usually handled by C<xsubpp>. See C<dSP> and | |
2541 | C<SPAGAIN>. | |
2542 | ||
2543 | =item SPAGAIN | |
2544 | ||
54310121 | 2545 | Refetch the stack pointer. Used after a callback. See L<perlcall>. |
cb1a09d0 AD |
2546 | |
2547 | SPAGAIN; | |
2548 | ||
2549 | =item ST | |
2550 | ||
2551 | Used to access elements on the XSUB's stack. | |
2552 | ||
e89caa19 | 2553 | SV* ST(int x) |
cb1a09d0 AD |
2554 | |
2555 | =item strEQ | |
2556 | ||
2557 | Test two strings to see if they are equal. Returns true or false. | |
2558 | ||
e89caa19 | 2559 | int strEQ( char *s1, char *s2 ) |
cb1a09d0 AD |
2560 | |
2561 | =item strGE | |
2562 | ||
2563 | Test two strings to see if the first, C<s1>, is greater than or equal to the | |
2564 | second, C<s2>. Returns true or false. | |
2565 | ||
e89caa19 | 2566 | int strGE( char *s1, char *s2 ) |
cb1a09d0 AD |
2567 | |
2568 | =item strGT | |
2569 | ||
2570 | Test two strings to see if the first, C<s1>, is greater than the second, | |
2571 | C<s2>. Returns true or false. | |
2572 | ||
e89caa19 | 2573 | int strGT( char *s1, char *s2 ) |
cb1a09d0 AD |
2574 | |
2575 | =item strLE | |
2576 | ||
2577 | Test two strings to see if the first, C<s1>, is less than or equal to the | |
2578 | second, C<s2>. Returns true or false. | |
2579 | ||
e89caa19 | 2580 | int strLE( char *s1, char *s2 ) |
cb1a09d0 AD |
2581 | |
2582 | =item strLT | |
2583 | ||
2584 | Test two strings to see if the first, C<s1>, is less than the second, | |
2585 | C<s2>. Returns true or false. | |
2586 | ||
e89caa19 | 2587 | int strLT( char *s1, char *s2 ) |
cb1a09d0 AD |
2588 | |
2589 | =item strNE | |
2590 | ||
2591 | Test two strings to see if they are different. Returns true or false. | |
2592 | ||
e89caa19 | 2593 | int strNE( char *s1, char *s2 ) |
cb1a09d0 AD |
2594 | |
2595 | =item strnEQ | |
2596 | ||
2597 | Test two strings to see if they are equal. The C<len> parameter indicates | |
2598 | the number of bytes to compare. Returns true or false. | |
2599 | ||
e89caa19 | 2600 | int strnEQ( char *s1, char *s2 ) |
cb1a09d0 AD |
2601 | |
2602 | =item strnNE | |
2603 | ||
2604 | Test two strings to see if they are different. The C<len> parameter | |
2605 | indicates the number of bytes to compare. Returns true or false. | |
2606 | ||
e89caa19 | 2607 | int strnNE( char *s1, char *s2, int len ) |
cb1a09d0 AD |
2608 | |
2609 | =item sv_2mortal | |
2610 | ||
2611 | Marks an SV as mortal. The SV will be destroyed when the current context | |
2612 | ends. | |
2613 | ||
ef50df4b | 2614 | SV* sv_2mortal (SV* sv) |
cb1a09d0 AD |
2615 | |
2616 | =item sv_bless | |
2617 | ||
2618 | Blesses an SV into a specified package. The SV must be an RV. The package | |
07fa94a1 JO |
2619 | must be designated by its stash (see C<gv_stashpv()>). The reference count |
2620 | of the SV is unaffected. | |
cb1a09d0 | 2621 | |
ef50df4b | 2622 | SV* sv_bless (SV* sv, HV* stash) |
cb1a09d0 | 2623 | |
ef50df4b | 2624 | =item sv_catpv |
189b2af5 | 2625 | |
ef50df4b GS |
2626 | Concatenates the string onto the end of the string which is in the SV. |
2627 | Handles 'get' magic, but not 'set' magic. See C<sv_catpv_mg>. | |
189b2af5 | 2628 | |
ef50df4b | 2629 | void sv_catpv (SV* sv, char* ptr) |
189b2af5 | 2630 | |
ef50df4b | 2631 | =item sv_catpv_mg |
cb1a09d0 | 2632 | |
ef50df4b | 2633 | Like C<sv_catpv>, but also handles 'set' magic. |
cb1a09d0 | 2634 | |
ef50df4b | 2635 | void sv_catpvn (SV* sv, char* ptr) |
cb1a09d0 AD |
2636 | |
2637 | =item sv_catpvn | |
2638 | ||
2639 | Concatenates the string onto the end of the string which is in the SV. The | |
189b2af5 | 2640 | C<len> indicates number of bytes to copy. Handles 'get' magic, but not |
ef50df4b | 2641 | 'set' magic. See C<sv_catpvn_mg>. |
cb1a09d0 | 2642 | |
ef50df4b GS |
2643 | void sv_catpvn (SV* sv, char* ptr, STRLEN len) |
2644 | ||
2645 | =item sv_catpvn_mg | |
2646 | ||
2647 | Like C<sv_catpvn>, but also handles 'set' magic. | |
2648 | ||
2649 | void sv_catpvn_mg (SV* sv, char* ptr, STRLEN len) | |
cb1a09d0 | 2650 | |
46fc3d4c | 2651 | =item sv_catpvf |
2652 | ||
2653 | Processes its arguments like C<sprintf> and appends the formatted output | |
189b2af5 GS |
2654 | to an SV. Handles 'get' magic, but not 'set' magic. C<SvSETMAGIC()> must |
2655 | typically be called after calling this function to handle 'set' magic. | |
46fc3d4c | 2656 | |
ef50df4b GS |
2657 | void sv_catpvf (SV* sv, const char* pat, ...) |
2658 | ||
2659 | =item sv_catpvf_mg | |
2660 | ||
2661 | Like C<sv_catpvf>, but also handles 'set' magic. | |
2662 | ||
2663 | void sv_catpvf_mg (SV* sv, const char* pat, ...) | |
46fc3d4c | 2664 | |
cb1a09d0 AD |
2665 | =item sv_catsv |
2666 | ||
5fb8527f | 2667 | Concatenates the string from SV C<ssv> onto the end of the string in SV |
ef50df4b GS |
2668 | C<dsv>. Handles 'get' magic, but not 'set' magic. See C<sv_catsv_mg>. |
2669 | ||
2670 | void sv_catsv (SV* dsv, SV* ssv) | |
2671 | ||
2672 | =item sv_catsv_mg | |
cb1a09d0 | 2673 | |
ef50df4b GS |
2674 | Like C<sv_catsv>, but also handles 'set' magic. |
2675 | ||
2676 | void sv_catsv_mg (SV* dsv, SV* ssv) | |
cb1a09d0 | 2677 | |
e89caa19 GA |
2678 | =item sv_chop |
2679 | ||
2680 | Efficient removal of characters from the beginning of the string | |
2681 | buffer. SvPOK(sv) must be true and the C<ptr> must be a pointer to | |
2682 | somewhere inside the string buffer. The C<ptr> becomes the first | |
2683 | character of the adjusted string. | |
2684 | ||
2685 | void sv_chop(SV* sv, char *ptr) | |
2686 | ||
2687 | ||
5fb8527f | 2688 | =item sv_cmp |
2689 | ||
2690 | Compares the strings in two SVs. Returns -1, 0, or 1 indicating whether the | |
2691 | string in C<sv1> is less than, equal to, or greater than the string in | |
2692 | C<sv2>. | |
2693 | ||
ef50df4b | 2694 | I32 sv_cmp (SV* sv1, SV* sv2) |
5fb8527f | 2695 | |
cb1a09d0 AD |
2696 | =item SvCUR |
2697 | ||
2698 | Returns the length of the string which is in the SV. See C<SvLEN>. | |
2699 | ||
e89caa19 | 2700 | int SvCUR (SV* sv) |
cb1a09d0 AD |
2701 | |
2702 | =item SvCUR_set | |
2703 | ||
2704 | Set the length of the string which is in the SV. See C<SvCUR>. | |
2705 | ||
e89caa19 | 2706 | void SvCUR_set (SV* sv, int val ) |
cb1a09d0 | 2707 | |
5fb8527f | 2708 | =item sv_dec |
2709 | ||
5f05dabc | 2710 | Auto-decrement of the value in the SV. |
5fb8527f | 2711 | |
ef50df4b | 2712 | void sv_dec (SV* sv) |
5fb8527f | 2713 | |
e89caa19 GA |
2714 | =item sv_derived_from |
2715 | ||
2716 | Returns a boolean indicating whether the SV is a subclass of the | |
2717 | specified class. | |
2718 | ||
2719 | int sv_derived_from(SV* sv, char* class) | |
2720 | ||
9abd00ed GS |
2721 | =item sv_derived_from |
2722 | ||
2723 | Returns a boolean indicating whether the SV is derived from the specified | |
2724 | class. This is the function that implements C<UNIVERSAL::isa>. It works | |
2725 | for class names as well as for objects. | |
2726 | ||
2727 | bool sv_derived_from _((SV* sv, char* name)); | |
2728 | ||
cb1a09d0 AD |
2729 | =item SvEND |
2730 | ||
2731 | Returns a pointer to the last character in the string which is in the SV. | |
2732 | See C<SvCUR>. Access the character as | |
2733 | ||
e89caa19 | 2734 | char* SvEND(sv) |
cb1a09d0 | 2735 | |
5fb8527f | 2736 | =item sv_eq |
2737 | ||
2738 | Returns a boolean indicating whether the strings in the two SVs are | |
2739 | identical. | |
2740 | ||
ef50df4b | 2741 | I32 sv_eq (SV* sv1, SV* sv2) |
5fb8527f | 2742 | |
189b2af5 GS |
2743 | =item SvGETMAGIC |
2744 | ||
2745 | Invokes C<mg_get> on an SV if it has 'get' magic. This macro evaluates | |
2746 | its argument more than once. | |
2747 | ||
2748 | void SvGETMAGIC( SV *sv ) | |
2749 | ||
cb1a09d0 AD |
2750 | =item SvGROW |
2751 | ||
e89caa19 GA |
2752 | Expands the character buffer in the SV so that it has room for the |
2753 | indicated number of bytes (remember to reserve space for an extra | |
2754 | trailing NUL character). Calls C<sv_grow> to perform the expansion if | |
2755 | necessary. Returns a pointer to the character buffer. | |
cb1a09d0 | 2756 | |
e89caa19 | 2757 | char* SvGROW( SV* sv, int len ) |
cb1a09d0 | 2758 | |
5fb8527f | 2759 | =item sv_grow |
2760 | ||
2761 | Expands the character buffer in the SV. This will use C<sv_unref> and will | |
2762 | upgrade the SV to C<SVt_PV>. Returns a pointer to the character buffer. | |
2763 | Use C<SvGROW>. | |
2764 | ||
2765 | =item sv_inc | |
2766 | ||
07fa94a1 | 2767 | Auto-increment of the value in the SV. |
5fb8527f | 2768 | |
ef50df4b | 2769 | void sv_inc (SV* sv) |
5fb8527f | 2770 | |
e89caa19 GA |
2771 | =item sv_insert |
2772 | ||
2773 | Inserts a string at the specified offset/length within the SV. | |
2774 | Similar to the Perl substr() function. | |
2775 | ||
2776 | void sv_insert(SV *sv, STRLEN offset, STRLEN len, | |
2777 | char *str, STRLEN strlen) | |
2778 | ||
cb1a09d0 AD |
2779 | =item SvIOK |
2780 | ||
2781 | Returns a boolean indicating whether the SV contains an integer. | |
2782 | ||
e89caa19 | 2783 | int SvIOK (SV* SV) |
cb1a09d0 AD |
2784 | |
2785 | =item SvIOK_off | |
2786 | ||
2787 | Unsets the IV status of an SV. | |
2788 | ||
e89caa19 | 2789 | void SvIOK_off (SV* sv) |
cb1a09d0 AD |
2790 | |
2791 | =item SvIOK_on | |
2792 | ||
2793 | Tells an SV that it is an integer. | |
2794 | ||
e89caa19 | 2795 | void SvIOK_on (SV* sv) |
cb1a09d0 | 2796 | |
5fb8527f | 2797 | =item SvIOK_only |
2798 | ||
2799 | Tells an SV that it is an integer and disables all other OK bits. | |
2800 | ||
e89caa19 | 2801 | void SvIOK_only (SV* sv) |
5fb8527f | 2802 | |
cb1a09d0 AD |
2803 | =item SvIOKp |
2804 | ||
2805 | Returns a boolean indicating whether the SV contains an integer. Checks the | |
2806 | B<private> setting. Use C<SvIOK>. | |
2807 | ||
e89caa19 | 2808 | int SvIOKp (SV* SV) |
cb1a09d0 AD |
2809 | |
2810 | =item sv_isa | |
2811 | ||
2812 | Returns a boolean indicating whether the SV is blessed into the specified | |
9abd00ed | 2813 | class. This does not check for subtypes; use C<sv_derived_from> to verify |
cb1a09d0 AD |
2814 | an inheritance relationship. |
2815 | ||
ef50df4b | 2816 | int sv_isa (SV* sv, char* name) |
cb1a09d0 | 2817 | |
cb1a09d0 AD |
2818 | =item sv_isobject |
2819 | ||
2820 | Returns a boolean indicating whether the SV is an RV pointing to a blessed | |
2821 | object. If the SV is not an RV, or if the object is not blessed, then this | |
2822 | will return false. | |
2823 | ||
ef50df4b | 2824 | int sv_isobject (SV* sv) |
cb1a09d0 | 2825 | |
e89caa19 GA |
2826 | =item SvIV |
2827 | ||
2828 | Returns the integer which is in the SV. | |
2829 | ||
9abd00ed | 2830 | int SvIV (SV* sv) |
a59f3522 | 2831 | |
cb1a09d0 AD |
2832 | =item SvIVX |
2833 | ||
2834 | Returns the integer which is stored in the SV. | |
2835 | ||
e89caa19 | 2836 | int SvIVX (SV* sv) |
cb1a09d0 AD |
2837 | |
2838 | =item SvLEN | |
2839 | ||
2840 | Returns the size of the string buffer in the SV. See C<SvCUR>. | |
2841 | ||
e89caa19 | 2842 | int SvLEN (SV* sv) |
cb1a09d0 | 2843 | |
5fb8527f | 2844 | =item sv_len |
2845 | ||
2846 | Returns the length of the string in the SV. Use C<SvCUR>. | |
2847 | ||
ef50df4b | 2848 | STRLEN sv_len (SV* sv) |
5fb8527f | 2849 | |
cb1a09d0 AD |
2850 | =item sv_magic |
2851 | ||
2852 | Adds magic to an SV. | |
2853 | ||
ef50df4b | 2854 | void sv_magic (SV* sv, SV* obj, int how, char* name, I32 namlen) |
cb1a09d0 AD |
2855 | |
2856 | =item sv_mortalcopy | |
2857 | ||
2858 | Creates a new SV which is a copy of the original SV. The new SV is marked | |
5f05dabc | 2859 | as mortal. |
cb1a09d0 | 2860 | |
ef50df4b | 2861 | SV* sv_mortalcopy (SV* oldsv) |
cb1a09d0 | 2862 | |
cb1a09d0 AD |
2863 | =item sv_newmortal |
2864 | ||
5f05dabc | 2865 | Creates a new SV which is mortal. The reference count of the SV is set to 1. |
cb1a09d0 | 2866 | |
ef50df4b | 2867 | SV* sv_newmortal (void) |
cb1a09d0 | 2868 | |
cb1a09d0 AD |
2869 | =item SvNIOK |
2870 | ||
2871 | Returns a boolean indicating whether the SV contains a number, integer or | |
2872 | double. | |
2873 | ||
e89caa19 | 2874 | int SvNIOK (SV* SV) |
cb1a09d0 AD |
2875 | |
2876 | =item SvNIOK_off | |
2877 | ||
2878 | Unsets the NV/IV status of an SV. | |
2879 | ||
e89caa19 | 2880 | void SvNIOK_off (SV* sv) |
cb1a09d0 AD |
2881 | |
2882 | =item SvNIOKp | |
2883 | ||
2884 | Returns a boolean indicating whether the SV contains a number, integer or | |
2885 | double. Checks the B<private> setting. Use C<SvNIOK>. | |
2886 | ||
e89caa19 GA |
2887 | int SvNIOKp (SV* SV) |
2888 | ||
9cde0e7f | 2889 | =item PL_sv_no |
e89caa19 | 2890 | |
9cde0e7f | 2891 | This is the C<false> SV. See C<PL_sv_yes>. Always refer to this as C<&PL_sv_no>. |
cb1a09d0 AD |
2892 | |
2893 | =item SvNOK | |
2894 | ||
2895 | Returns a boolean indicating whether the SV contains a double. | |
2896 | ||
e89caa19 | 2897 | int SvNOK (SV* SV) |
cb1a09d0 AD |
2898 | |
2899 | =item SvNOK_off | |
2900 | ||
2901 | Unsets the NV status of an SV. | |
2902 | ||
e89caa19 | 2903 | void SvNOK_off (SV* sv) |
cb1a09d0 AD |
2904 | |
2905 | =item SvNOK_on | |
2906 | ||
2907 | Tells an SV that it is a double. | |
2908 | ||
e89caa19 | 2909 | void SvNOK_on (SV* sv) |
cb1a09d0 | 2910 | |
5fb8527f | 2911 | =item SvNOK_only |
2912 | ||
2913 | Tells an SV that it is a double and disables all other OK bits. | |
2914 | ||
e89caa19 | 2915 | void SvNOK_only (SV* sv) |
5fb8527f | 2916 | |
cb1a09d0 AD |
2917 | =item SvNOKp |
2918 | ||
2919 | Returns a boolean indicating whether the SV contains a double. Checks the | |
2920 | B<private> setting. Use C<SvNOK>. | |
2921 | ||
e89caa19 | 2922 | int SvNOKp (SV* SV) |
cb1a09d0 AD |
2923 | |
2924 | =item SvNV | |
2925 | ||
2926 | Returns the double which is stored in the SV. | |
2927 | ||
e89caa19 | 2928 | double SvNV (SV* sv) |
cb1a09d0 AD |
2929 | |
2930 | =item SvNVX | |
2931 | ||
2932 | Returns the double which is stored in the SV. | |
2933 | ||
e89caa19 GA |
2934 | double SvNVX (SV* sv) |
2935 | ||
2936 | =item SvOK | |
2937 | ||
2938 | Returns a boolean indicating whether the value is an SV. | |
2939 | ||
2940 | int SvOK (SV* sv) | |
2941 | ||
2942 | =item SvOOK | |
2943 | ||
2944 | Returns a boolean indicating whether the SvIVX is a valid offset value | |
2945 | for the SvPVX. This hack is used internally to speed up removal of | |
2946 | characters from the beginning of a SvPV. When SvOOK is true, then the | |
2947 | start of the allocated string buffer is really (SvPVX - SvIVX). | |
2948 | ||
9cde0e7f | 2949 | int SvOOK(SV* sv) |
cb1a09d0 AD |
2950 | |
2951 | =item SvPOK | |
2952 | ||
2953 | Returns a boolean indicating whether the SV contains a character string. | |
2954 | ||
e89caa19 | 2955 | int SvPOK (SV* SV) |
cb1a09d0 AD |
2956 | |
2957 | =item SvPOK_off | |
2958 | ||
2959 | Unsets the PV status of an SV. | |
2960 | ||
e89caa19 | 2961 | void SvPOK_off (SV* sv) |
cb1a09d0 AD |
2962 | |
2963 | =item SvPOK_on | |
2964 | ||
2965 | Tells an SV that it is a string. | |
2966 | ||
e89caa19 | 2967 | void SvPOK_on (SV* sv) |
cb1a09d0 | 2968 | |
5fb8527f | 2969 | =item SvPOK_only |
2970 | ||
2971 | Tells an SV that it is a string and disables all other OK bits. | |
2972 | ||
e89caa19 | 2973 | void SvPOK_only (SV* sv) |
5fb8527f | 2974 | |
cb1a09d0 AD |
2975 | =item SvPOKp |
2976 | ||
2977 | Returns a boolean indicating whether the SV contains a character string. | |
2978 | Checks the B<private> setting. Use C<SvPOK>. | |
2979 | ||
e89caa19 | 2980 | int SvPOKp (SV* SV) |
cb1a09d0 AD |
2981 | |
2982 | =item SvPV | |
2983 | ||
2984 | Returns a pointer to the string in the SV, or a stringified form of the SV | |
9cde0e7f | 2985 | if the SV does not contain a string. If C<len> is C<PL_na> then Perl will |
189b2af5 | 2986 | handle the length on its own. Handles 'get' magic. |
cb1a09d0 | 2987 | |
e89caa19 GA |
2988 | char* SvPV (SV* sv, int len ) |
2989 | ||
2990 | =item SvPV_force | |
2991 | ||
2992 | Like <SvPV> but will force the SV into becoming a string (SvPOK). You | |
2993 | want force if you are going to update the SvPVX directly. | |
2994 | ||
2995 | char* SvPV_force(SV* sv, int len) | |
2996 | ||
cb1a09d0 AD |
2997 | |
2998 | =item SvPVX | |
2999 | ||
3000 | Returns a pointer to the string in the SV. The SV must contain a string. | |
3001 | ||
e89caa19 | 3002 | char* SvPVX (SV* sv) |
cb1a09d0 AD |
3003 | |
3004 | =item SvREFCNT | |
3005 | ||
5f05dabc | 3006 | Returns the value of the object's reference count. |
cb1a09d0 | 3007 | |
e89caa19 | 3008 | int SvREFCNT (SV* sv) |
cb1a09d0 AD |
3009 | |
3010 | =item SvREFCNT_dec | |
3011 | ||
5f05dabc | 3012 | Decrements the reference count of the given SV. |
cb1a09d0 | 3013 | |
e89caa19 | 3014 | void SvREFCNT_dec (SV* sv) |
cb1a09d0 AD |
3015 | |
3016 | =item SvREFCNT_inc | |
3017 | ||
5f05dabc | 3018 | Increments the reference count of the given SV. |
cb1a09d0 | 3019 | |
e89caa19 | 3020 | void SvREFCNT_inc (SV* sv) |
cb1a09d0 AD |
3021 | |
3022 | =item SvROK | |
3023 | ||
3024 | Tests if the SV is an RV. | |
3025 | ||
e89caa19 | 3026 | int SvROK (SV* sv) |
cb1a09d0 AD |
3027 | |
3028 | =item SvROK_off | |
3029 | ||
3030 | Unsets the RV status of an SV. | |
3031 | ||
e89caa19 | 3032 | void SvROK_off (SV* sv) |
cb1a09d0 AD |
3033 | |
3034 | =item SvROK_on | |
3035 | ||
3036 | Tells an SV that it is an RV. | |
3037 | ||
e89caa19 | 3038 | void SvROK_on (SV* sv) |
cb1a09d0 AD |
3039 | |
3040 | =item SvRV | |
3041 | ||
3042 | Dereferences an RV to return the SV. | |
3043 | ||
ef50df4b | 3044 | SV* SvRV (SV* sv) |
cb1a09d0 | 3045 | |
189b2af5 GS |
3046 | =item SvSETMAGIC |
3047 | ||
3048 | Invokes C<mg_set> on an SV if it has 'set' magic. This macro evaluates | |
3049 | its argument more than once. | |
3050 | ||
3051 | void SvSETMAGIC( SV *sv ) | |
3052 | ||
ef50df4b | 3053 | =item sv_setiv |
189b2af5 | 3054 | |
ef50df4b GS |
3055 | Copies an integer into the given SV. Does not handle 'set' magic. |
3056 | See C<sv_setiv_mg>. | |
189b2af5 | 3057 | |
ef50df4b | 3058 | void sv_setiv (SV* sv, IV num) |
189b2af5 | 3059 | |
ef50df4b | 3060 | =item sv_setiv_mg |
189b2af5 | 3061 | |
ef50df4b | 3062 | Like C<sv_setiv>, but also handles 'set' magic. |
189b2af5 | 3063 | |
ef50df4b | 3064 | void sv_setiv_mg (SV* sv, IV num) |
189b2af5 | 3065 | |
ef50df4b | 3066 | =item sv_setnv |
189b2af5 | 3067 | |
ef50df4b GS |
3068 | Copies a double into the given SV. Does not handle 'set' magic. |
3069 | See C<sv_setnv_mg>. | |
189b2af5 | 3070 | |
ef50df4b | 3071 | void sv_setnv (SV* sv, double num) |
189b2af5 | 3072 | |
ef50df4b | 3073 | =item sv_setnv_mg |
189b2af5 | 3074 | |
ef50df4b | 3075 | Like C<sv_setnv>, but also handles 'set' magic. |
189b2af5 | 3076 | |
ef50df4b | 3077 | void sv_setnv_mg (SV* sv, double num) |
189b2af5 | 3078 | |
ef50df4b | 3079 | =item sv_setpv |
189b2af5 | 3080 | |
ef50df4b GS |
3081 | Copies a string into an SV. The string must be null-terminated. |
3082 | Does not handle 'set' magic. See C<sv_setpv_mg>. | |
189b2af5 | 3083 | |
ef50df4b | 3084 | void sv_setpv (SV* sv, char* ptr) |
189b2af5 | 3085 | |
ef50df4b | 3086 | =item sv_setpv_mg |
189b2af5 | 3087 | |
ef50df4b | 3088 | Like C<sv_setpv>, but also handles 'set' magic. |
189b2af5 | 3089 | |
ef50df4b | 3090 | void sv_setpv_mg (SV* sv, char* ptr) |
189b2af5 | 3091 | |
ef50df4b | 3092 | =item sv_setpviv |
cb1a09d0 | 3093 | |
ef50df4b GS |
3094 | Copies an integer into the given SV, also updating its string value. |
3095 | Does not handle 'set' magic. See C<sv_setpviv_mg>. | |
cb1a09d0 | 3096 | |
ef50df4b | 3097 | void sv_setpviv (SV* sv, IV num) |
cb1a09d0 | 3098 | |
ef50df4b | 3099 | =item sv_setpviv_mg |
cb1a09d0 | 3100 | |
ef50df4b | 3101 | Like C<sv_setpviv>, but also handles 'set' magic. |
cb1a09d0 | 3102 | |
ef50df4b | 3103 | void sv_setpviv_mg (SV* sv, IV num) |
cb1a09d0 | 3104 | |
ef50df4b | 3105 | =item sv_setpvn |
cb1a09d0 | 3106 | |
ef50df4b GS |
3107 | Copies a string into an SV. The C<len> parameter indicates the number of |
3108 | bytes to be copied. Does not handle 'set' magic. See C<sv_setpvn_mg>. | |
cb1a09d0 | 3109 | |
ef50df4b | 3110 | void sv_setpvn (SV* sv, char* ptr, STRLEN len) |
cb1a09d0 | 3111 | |
ef50df4b | 3112 | =item sv_setpvn_mg |
189b2af5 | 3113 | |
ef50df4b | 3114 | Like C<sv_setpvn>, but also handles 'set' magic. |
189b2af5 | 3115 | |
ef50df4b | 3116 | void sv_setpvn_mg (SV* sv, char* ptr, STRLEN len) |
189b2af5 | 3117 | |
ef50df4b | 3118 | =item sv_setpvf |
cb1a09d0 | 3119 | |
ef50df4b GS |
3120 | Processes its arguments like C<sprintf> and sets an SV to the formatted |
3121 | output. Does not handle 'set' magic. See C<sv_setpvf_mg>. | |
cb1a09d0 | 3122 | |
ef50df4b | 3123 | void sv_setpvf (SV* sv, const char* pat, ...) |
cb1a09d0 | 3124 | |
ef50df4b | 3125 | =item sv_setpvf_mg |
46fc3d4c | 3126 | |
ef50df4b | 3127 | Like C<sv_setpvf>, but also handles 'set' magic. |
46fc3d4c | 3128 | |
ef50df4b | 3129 | void sv_setpvf_mg (SV* sv, const char* pat, ...) |
46fc3d4c | 3130 | |
cb1a09d0 AD |
3131 | =item sv_setref_iv |
3132 | ||
5fb8527f | 3133 | Copies an integer into a new SV, optionally blessing the SV. The C<rv> |
3134 | argument will be upgraded to an RV. That RV will be modified to point to | |
3135 | the new SV. The C<classname> argument indicates the package for the | |
3136 | blessing. Set C<classname> to C<Nullch> to avoid the blessing. The new SV | |
5f05dabc | 3137 | will be returned and will have a reference count of 1. |
cb1a09d0 | 3138 | |
ef50df4b | 3139 | SV* sv_setref_iv (SV *rv, char *classname, IV iv) |
cb1a09d0 AD |
3140 | |
3141 | =item sv_setref_nv | |
3142 | ||
5fb8527f | 3143 | Copies a double into a new SV, optionally blessing the SV. The C<rv> |
3144 | argument will be upgraded to an RV. That RV will be modified to point to | |
3145 | the new SV. The C<classname> argument indicates the package for the | |
3146 | blessing. Set C<classname> to C<Nullch> to avoid the blessing. The new SV | |
5f05dabc | 3147 | will be returned and will have a reference count of 1. |
cb1a09d0 | 3148 | |
ef50df4b | 3149 | SV* sv_setref_nv (SV *rv, char *classname, double nv) |
cb1a09d0 AD |
3150 | |
3151 | =item sv_setref_pv | |
3152 | ||
5fb8527f | 3153 | Copies a pointer into a new SV, optionally blessing the SV. The C<rv> |
3154 | argument will be upgraded to an RV. That RV will be modified to point to | |
9cde0e7f | 3155 | the new SV. If the C<pv> argument is NULL then C<PL_sv_undef> will be placed |
5fb8527f | 3156 | into the SV. The C<classname> argument indicates the package for the |
3157 | blessing. Set C<classname> to C<Nullch> to avoid the blessing. The new SV | |
5f05dabc | 3158 | will be returned and will have a reference count of 1. |
cb1a09d0 | 3159 | |
ef50df4b | 3160 | SV* sv_setref_pv (SV *rv, char *classname, void* pv) |
cb1a09d0 AD |
3161 | |
3162 | Do not use with integral Perl types such as HV, AV, SV, CV, because those | |
3163 | objects will become corrupted by the pointer copy process. | |
3164 | ||
3165 | Note that C<sv_setref_pvn> copies the string while this copies the pointer. | |
3166 | ||
3167 | =item sv_setref_pvn | |
3168 | ||
5fb8527f | 3169 | Copies a string into a new SV, optionally blessing the SV. The length of the |
3170 | string must be specified with C<n>. The C<rv> argument will be upgraded to | |
3171 | an RV. That RV will be modified to point to the new SV. The C<classname> | |
cb1a09d0 AD |
3172 | argument indicates the package for the blessing. Set C<classname> to |
3173 | C<Nullch> to avoid the blessing. The new SV will be returned and will have | |
5f05dabc | 3174 | a reference count of 1. |
cb1a09d0 | 3175 | |
ef50df4b | 3176 | SV* sv_setref_pvn (SV *rv, char *classname, char* pv, I32 n) |
cb1a09d0 AD |
3177 | |
3178 | Note that C<sv_setref_pv> copies the pointer while this copies the string. | |
3179 | ||
189b2af5 GS |
3180 | =item SvSetSV |
3181 | ||
3182 | Calls C<sv_setsv> if dsv is not the same as ssv. May evaluate arguments | |
3183 | more than once. | |
3184 | ||
3185 | void SvSetSV (SV* dsv, SV* ssv) | |
3186 | ||
3187 | =item SvSetSV_nosteal | |
3188 | ||
3189 | Calls a non-destructive version of C<sv_setsv> if dsv is not the same as ssv. | |
3190 | May evaluate arguments more than once. | |
3191 | ||
3192 | void SvSetSV_nosteal (SV* dsv, SV* ssv) | |
3193 | ||
cb1a09d0 AD |
3194 | =item sv_setsv |
3195 | ||
3196 | Copies the contents of the source SV C<ssv> into the destination SV C<dsv>. | |
189b2af5 | 3197 | The source SV may be destroyed if it is mortal. Does not handle 'set' magic. |
ef50df4b GS |
3198 | See the macro forms C<SvSetSV>, C<SvSetSV_nosteal> and C<sv_setsv_mg>. |
3199 | ||
3200 | void sv_setsv (SV* dsv, SV* ssv) | |
3201 | ||
3202 | =item sv_setsv_mg | |
3203 | ||
3204 | Like C<sv_setsv>, but also handles 'set' magic. | |
cb1a09d0 | 3205 | |
ef50df4b | 3206 | void sv_setsv_mg (SV* dsv, SV* ssv) |
cb1a09d0 | 3207 | |
189b2af5 GS |
3208 | =item sv_setuv |
3209 | ||
3210 | Copies an unsigned integer into the given SV. Does not handle 'set' magic. | |
ef50df4b | 3211 | See C<sv_setuv_mg>. |
189b2af5 | 3212 | |
ef50df4b GS |
3213 | void sv_setuv (SV* sv, UV num) |
3214 | ||
3215 | =item sv_setuv_mg | |
3216 | ||
3217 | Like C<sv_setuv>, but also handles 'set' magic. | |
3218 | ||
3219 | void sv_setuv_mg (SV* sv, UV num) | |
189b2af5 | 3220 | |
cb1a09d0 AD |
3221 | =item SvSTASH |
3222 | ||
3223 | Returns the stash of the SV. | |
3224 | ||
e89caa19 GA |
3225 | HV* SvSTASH (SV* sv) |
3226 | ||
3227 | =item SvTAINT | |
3228 | ||
3229 | Taints an SV if tainting is enabled | |
3230 | ||
3231 | void SvTAINT (SV* sv) | |
3232 | ||
3233 | =item SvTAINTED | |
3234 | ||
3235 | Checks to see if an SV is tainted. Returns TRUE if it is, FALSE if not. | |
3236 | ||
3237 | int SvTAINTED (SV* sv) | |
3238 | ||
3239 | =item SvTAINTED_off | |
3240 | ||
3241 | Untaints an SV. Be I<very> careful with this routine, as it short-circuits | |
3242 | some of Perl's fundamental security features. XS module authors should | |
3243 | not use this function unless they fully understand all the implications | |
3244 | of unconditionally untainting the value. Untainting should be done in | |
3245 | the standard perl fashion, via a carefully crafted regexp, rather than | |
3246 | directly untainting variables. | |
3247 | ||
3248 | void SvTAINTED_off (SV* sv) | |
3249 | ||
3250 | =item SvTAINTED_on | |
3251 | ||
3252 | Marks an SV as tainted. | |
3253 | ||
3254 | void SvTAINTED_on (SV* sv) | |
cb1a09d0 AD |
3255 | |
3256 | =item SVt_IV | |
3257 | ||
3258 | Integer type flag for scalars. See C<svtype>. | |
3259 | ||
3260 | =item SVt_PV | |
3261 | ||
3262 | Pointer type flag for scalars. See C<svtype>. | |
3263 | ||
3264 | =item SVt_PVAV | |
3265 | ||
3266 | Type flag for arrays. See C<svtype>. | |
3267 | ||
3268 | =item SVt_PVCV | |
3269 | ||
3270 | Type flag for code refs. See C<svtype>. | |
3271 | ||
3272 | =item SVt_PVHV | |
3273 | ||
3274 | Type flag for hashes. See C<svtype>. | |
3275 | ||
3276 | =item SVt_PVMG | |
3277 | ||
3278 | Type flag for blessed scalars. See C<svtype>. | |
3279 | ||
3280 | =item SVt_NV | |
3281 | ||
3282 | Double type flag for scalars. See C<svtype>. | |
3283 | ||
3284 | =item SvTRUE | |
3285 | ||
3286 | Returns a boolean indicating whether Perl would evaluate the SV as true or | |
189b2af5 | 3287 | false, defined or undefined. Does not handle 'get' magic. |
cb1a09d0 | 3288 | |
e89caa19 | 3289 | int SvTRUE (SV* sv) |
cb1a09d0 AD |
3290 | |
3291 | =item SvTYPE | |
3292 | ||
3293 | Returns the type of the SV. See C<svtype>. | |
3294 | ||
3295 | svtype SvTYPE (SV* sv) | |
3296 | ||
3297 | =item svtype | |
3298 | ||
3299 | An enum of flags for Perl types. These are found in the file B<sv.h> in the | |
3300 | C<svtype> enum. Test these flags with the C<SvTYPE> macro. | |
3301 | ||
9cde0e7f | 3302 | =item PL_sv_undef |
cb1a09d0 | 3303 | |
9cde0e7f | 3304 | This is the C<undef> SV. Always refer to this as C<&PL_sv_undef>. |
cb1a09d0 | 3305 | |
5fb8527f | 3306 | =item sv_unref |
3307 | ||
07fa94a1 JO |
3308 | Unsets the RV status of the SV, and decrements the reference count of |
3309 | whatever was being referenced by the RV. This can almost be thought of | |
3310 | as a reversal of C<newSVrv>. See C<SvROK_off>. | |
5fb8527f | 3311 | |
ef50df4b | 3312 | void sv_unref (SV* sv) |
189b2af5 | 3313 | |
e89caa19 GA |
3314 | =item SvUPGRADE |
3315 | ||
3316 | Used to upgrade an SV to a more complex form. Uses C<sv_upgrade> to perform | |
3317 | the upgrade if necessary. See C<svtype>. | |
3318 | ||
3319 | bool SvUPGRADE (SV* sv, svtype mt) | |
3320 | ||
3321 | =item sv_upgrade | |
3322 | ||
3323 | Upgrade an SV to a more complex form. Use C<SvUPGRADE>. See C<svtype>. | |
3324 | ||
cb1a09d0 AD |
3325 | =item sv_usepvn |
3326 | ||
3327 | Tells an SV to use C<ptr> to find its string value. Normally the string is | |
5fb8527f | 3328 | stored inside the SV but sv_usepvn allows the SV to use an outside string. |
3329 | The C<ptr> should point to memory that was allocated by C<malloc>. The | |
cb1a09d0 AD |
3330 | string length, C<len>, must be supplied. This function will realloc the |
3331 | memory pointed to by C<ptr>, so that pointer should not be freed or used by | |
189b2af5 | 3332 | the programmer after giving it to sv_usepvn. Does not handle 'set' magic. |
ef50df4b GS |
3333 | See C<sv_usepvn_mg>. |
3334 | ||
3335 | void sv_usepvn (SV* sv, char* ptr, STRLEN len) | |
3336 | ||
3337 | =item sv_usepvn_mg | |
3338 | ||
3339 | Like C<sv_usepvn>, but also handles 'set' magic. | |
cb1a09d0 | 3340 | |
ef50df4b | 3341 | void sv_usepvn_mg (SV* sv, char* ptr, STRLEN len) |
cb1a09d0 | 3342 | |
9abd00ed GS |
3343 | =item sv_vcatpvfn(sv, pat, patlen, args, svargs, svmax, used_locale) |
3344 | ||
3345 | Processes its arguments like C<vsprintf> and appends the formatted output | |
3346 | to an SV. Uses an array of SVs if the C style variable argument list is | |
3347 | missing (NULL). Indicates if locale information has been used for formatting. | |
3348 | ||
3349 | void sv_catpvfn _((SV* sv, const char* pat, STRLEN patlen, | |
3350 | va_list *args, SV **svargs, I32 svmax, | |
3351 | bool *used_locale)); | |
3352 | ||
3353 | =item sv_vsetpvfn(sv, pat, patlen, args, svargs, svmax, used_locale) | |
3354 | ||
3355 | Works like C<vcatpvfn> but copies the text into the SV instead of | |
3356 | appending it. | |
3357 | ||
3358 | void sv_setpvfn _((SV* sv, const char* pat, STRLEN patlen, | |
3359 | va_list *args, SV **svargs, I32 svmax, | |
3360 | bool *used_locale)); | |
3361 | ||
e89caa19 GA |
3362 | =item SvUV |
3363 | ||
3364 | Returns the unsigned integer which is in the SV. | |
3365 | ||
3366 | UV SvUV(SV* sv) | |
3367 | ||
3368 | =item SvUVX | |
3369 | ||
3370 | Returns the unsigned integer which is stored in the SV. | |
3371 | ||
3372 | UV SvUVX(SV* sv) | |
3373 | ||
9cde0e7f | 3374 | =item PL_sv_yes |
cb1a09d0 | 3375 | |
9cde0e7f | 3376 | This is the C<true> SV. See C<PL_sv_no>. Always refer to this as C<&PL_sv_yes>. |
cb1a09d0 AD |
3377 | |
3378 | =item THIS | |
3379 | ||
3380 | Variable which is setup by C<xsubpp> to designate the object in a C++ XSUB. | |
3381 | This is always the proper type for the C++ object. See C<CLASS> and | |
5fb8527f | 3382 | L<perlxs/"Using XS With C++">. |
cb1a09d0 AD |
3383 | |
3384 | =item toLOWER | |
3385 | ||
3386 | Converts the specified character to lowercase. | |
3387 | ||
e89caa19 | 3388 | int toLOWER (char c) |
cb1a09d0 AD |
3389 | |
3390 | =item toUPPER | |
3391 | ||
3392 | Converts the specified character to uppercase. | |
3393 | ||
e89caa19 | 3394 | int toUPPER (char c) |
cb1a09d0 AD |
3395 | |
3396 | =item warn | |
3397 | ||
3398 | This is the XSUB-writer's interface to Perl's C<warn> function. Use this | |
3399 | function the same way you use the C C<printf> function. See C<croak()>. | |
3400 | ||
3401 | =item XPUSHi | |
3402 | ||
189b2af5 GS |
3403 | Push an integer onto the stack, extending the stack if necessary. Handles |
3404 | 'set' magic. See C<PUSHi>. | |
cb1a09d0 AD |
3405 | |
3406 | XPUSHi(int d) | |
3407 | ||
3408 | =item XPUSHn | |
3409 | ||
189b2af5 GS |
3410 | Push a double onto the stack, extending the stack if necessary. Handles 'set' |
3411 | magic. See C<PUSHn>. | |
cb1a09d0 AD |
3412 | |
3413 | XPUSHn(double d) | |
3414 | ||
3415 | =item XPUSHp | |
3416 | ||
3417 | Push a string onto the stack, extending the stack if necessary. The C<len> | |
189b2af5 | 3418 | indicates the length of the string. Handles 'set' magic. See C<PUSHp>. |
cb1a09d0 AD |
3419 | |
3420 | XPUSHp(char *c, int len) | |
3421 | ||
3422 | =item XPUSHs | |
3423 | ||
189b2af5 GS |
3424 | Push an SV onto the stack, extending the stack if necessary. Does not |
3425 | handle 'set' magic. See C<PUSHs>. | |
cb1a09d0 AD |
3426 | |
3427 | XPUSHs(sv) | |
3428 | ||
e89caa19 GA |
3429 | =item XPUSHu |
3430 | ||
3431 | Push an unsigned integer onto the stack, extending the stack if | |
3432 | necessary. See C<PUSHu>. | |
3433 | ||
5fb8527f | 3434 | =item XS |
3435 | ||
3436 | Macro to declare an XSUB and its C parameter list. This is handled by | |
3437 | C<xsubpp>. | |
3438 | ||
cb1a09d0 AD |
3439 | =item XSRETURN |
3440 | ||
3441 | Return from XSUB, indicating number of items on the stack. This is usually | |
3442 | handled by C<xsubpp>. | |
3443 | ||
ef50df4b | 3444 | XSRETURN(int x) |
cb1a09d0 AD |
3445 | |
3446 | =item XSRETURN_EMPTY | |
3447 | ||
5fb8527f | 3448 | Return an empty list from an XSUB immediately. |
cb1a09d0 AD |
3449 | |
3450 | XSRETURN_EMPTY; | |
3451 | ||
5fb8527f | 3452 | =item XSRETURN_IV |
3453 | ||
3454 | Return an integer from an XSUB immediately. Uses C<XST_mIV>. | |
3455 | ||
ef50df4b | 3456 | XSRETURN_IV(IV v) |
5fb8527f | 3457 | |
cb1a09d0 AD |
3458 | =item XSRETURN_NO |
3459 | ||
9cde0e7f | 3460 | Return C<&PL_sv_no> from an XSUB immediately. Uses C<XST_mNO>. |
cb1a09d0 AD |
3461 | |
3462 | XSRETURN_NO; | |
3463 | ||
5fb8527f | 3464 | =item XSRETURN_NV |
3465 | ||
3466 | Return an double from an XSUB immediately. Uses C<XST_mNV>. | |
3467 | ||
ef50df4b | 3468 | XSRETURN_NV(NV v) |
5fb8527f | 3469 | |
3470 | =item XSRETURN_PV | |
3471 | ||
3472 | Return a copy of a string from an XSUB immediately. Uses C<XST_mPV>. | |
3473 | ||
ef50df4b | 3474 | XSRETURN_PV(char *v) |
5fb8527f | 3475 | |
cb1a09d0 AD |
3476 | =item XSRETURN_UNDEF |
3477 | ||
9cde0e7f | 3478 | Return C<&PL_sv_undef> from an XSUB immediately. Uses C<XST_mUNDEF>. |
cb1a09d0 AD |
3479 | |
3480 | XSRETURN_UNDEF; | |
3481 | ||
3482 | =item XSRETURN_YES | |
3483 | ||
9cde0e7f | 3484 | Return C<&PL_sv_yes> from an XSUB immediately. Uses C<XST_mYES>. |
cb1a09d0 AD |
3485 | |
3486 | XSRETURN_YES; | |
3487 | ||
5fb8527f | 3488 | =item XST_mIV |
3489 | ||
3490 | Place an integer into the specified position C<i> on the stack. The value is | |
3491 | stored in a new mortal SV. | |
3492 | ||
ef50df4b | 3493 | XST_mIV( int i, IV v ) |
5fb8527f | 3494 | |
3495 | =item XST_mNV | |
3496 | ||
3497 | Place a double into the specified position C<i> on the stack. The value is | |
3498 | stored in a new mortal SV. | |
3499 | ||
ef50df4b | 3500 | XST_mNV( int i, NV v ) |
5fb8527f | 3501 | |
3502 | =item XST_mNO | |
3503 | ||
9cde0e7f | 3504 | Place C<&PL_sv_no> into the specified position C<i> on the stack. |
5fb8527f | 3505 | |
ef50df4b | 3506 | XST_mNO( int i ) |
5fb8527f | 3507 | |
3508 | =item XST_mPV | |
3509 | ||
3510 | Place a copy of a string into the specified position C<i> on the stack. The | |
3511 | value is stored in a new mortal SV. | |
3512 | ||
ef50df4b | 3513 | XST_mPV( int i, char *v ) |
5fb8527f | 3514 | |
3515 | =item XST_mUNDEF | |
3516 | ||
9cde0e7f | 3517 | Place C<&PL_sv_undef> into the specified position C<i> on the stack. |
5fb8527f | 3518 | |
ef50df4b | 3519 | XST_mUNDEF( int i ) |
5fb8527f | 3520 | |
3521 | =item XST_mYES | |
3522 | ||
9cde0e7f | 3523 | Place C<&PL_sv_yes> into the specified position C<i> on the stack. |
5fb8527f | 3524 | |
ef50df4b | 3525 | XST_mYES( int i ) |
5fb8527f | 3526 | |
3527 | =item XS_VERSION | |
3528 | ||
3529 | The version identifier for an XS module. This is usually handled | |
3530 | automatically by C<ExtUtils::MakeMaker>. See C<XS_VERSION_BOOTCHECK>. | |
3531 | ||
3532 | =item XS_VERSION_BOOTCHECK | |
3533 | ||
3534 | Macro to verify that a PM module's $VERSION variable matches the XS module's | |
3535 | C<XS_VERSION> variable. This is usually handled automatically by | |
3536 | C<xsubpp>. See L<perlxs/"The VERSIONCHECK: Keyword">. | |
3537 | ||
cb1a09d0 AD |
3538 | =item Zero |
3539 | ||
3540 | The XSUB-writer's interface to the C C<memzero> function. The C<d> is the | |
3541 | destination, C<n> is the number of items, and C<t> is the type. | |
3542 | ||
e89caa19 | 3543 | void Zero( d, n, t ) |
cb1a09d0 AD |
3544 | |
3545 | =back | |
3546 | ||
9cecd9f2 | 3547 | =head1 AUTHORS |
cb1a09d0 | 3548 | |
9cecd9f2 GA |
3549 | Until May 1997, this document was maintained by Jeff Okamoto |
3550 | <okamoto@corp.hp.com>. It is now maintained as part of Perl itself. | |
cb1a09d0 AD |
3551 | |
3552 | With lots of help and suggestions from Dean Roehrich, Malcolm Beattie, | |
3553 | Andreas Koenig, Paul Hudson, Ilya Zakharevich, Paul Marquess, Neil | |
189b2af5 GS |
3554 | Bowers, Matthew Green, Tim Bunce, Spider Boardman, Ulrich Pfeifer, |
3555 | Stephen McCamant, and Gurusamy Sarathy. | |
cb1a09d0 | 3556 | |
9cecd9f2 | 3557 | API Listing originally by Dean Roehrich <roehrich@cray.com>. |