1 /*    sv.h
2  *
3  *    Copyright (C) 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000,
4  *    2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009 by Larry Wall and others
5  *
6  *    You may distribute under the terms of either the GNU General Public
7  *    License or the Artistic License, as specified in the README file.
8  *
9  */
10 
11 #ifdef sv_flags
12 #undef sv_flags		/* Convex has this in <signal.h> for sigvec() */
13 #endif
14 
15 /*
16 =for apidoc_section $SV_flags
17 
18 =for apidoc Ay||svtype
19 An enum of flags for Perl types.  These are found in the file F<sv.h>
20 in the C<svtype> enum.  Test these flags with the C<SvTYPE> macro.
21 
22 The types are:
23 
24     SVt_NULL
25     SVt_IV
26     SVt_NV
27     SVt_RV
28     SVt_PV
29     SVt_PVIV
30     SVt_PVNV
31     SVt_PVMG
32     SVt_INVLIST
33     SVt_REGEXP
34     SVt_PVGV
35     SVt_PVLV
36     SVt_PVAV
37     SVt_PVHV
38     SVt_PVCV
39     SVt_PVFM
40     SVt_PVIO
41 
42 These are most easily explained from the bottom up.
43 
44 C<SVt_PVIO> is for I/O objects, C<SVt_PVFM> for formats, C<SVt_PVCV> for
45 subroutines, C<SVt_PVHV> for hashes and C<SVt_PVAV> for arrays.
46 
47 All the others are scalar types, that is, things that can be bound to a
48 C<$> variable.  For these, the internal types are mostly orthogonal to
49 types in the Perl language.
50 
51 Hence, checking C<< SvTYPE(sv) < SVt_PVAV >> is the best way to see whether
52 something is a scalar.
53 
54 C<SVt_PVGV> represents a typeglob.  If C<!SvFAKE(sv)>, then it is a real,
55 incoercible typeglob.  If C<SvFAKE(sv)>, then it is a scalar to which a
56 typeglob has been assigned.  Assigning to it again will stop it from being
57 a typeglob.  C<SVt_PVLV> represents a scalar that delegates to another scalar
58 behind the scenes.  It is used, e.g., for the return value of C<substr> and
59 for tied hash and array elements.  It can hold any scalar value, including
60 a typeglob.  C<SVt_REGEXP> is for regular
61 expressions.  C<SVt_INVLIST> is for Perl
62 core internal use only.
63 
64 C<SVt_PVMG> represents a "normal" scalar (not a typeglob, regular expression,
65 or delegate).  Since most scalars do not need all the internal fields of a
66 PVMG, we save memory by allocating smaller structs when possible.  All the
67 other types are just simpler forms of C<SVt_PVMG>, with fewer internal fields.
68 C<SVt_NULL> can only hold undef.  C<SVt_IV> can hold undef, an integer, or a
69 reference.  (C<SVt_RV> is an alias for C<SVt_IV>, which exists for backward
70 compatibility.)  C<SVt_NV> can hold any of those or a double.  C<SVt_PV> can only
71 hold C<undef> or a string.  C<SVt_PVIV> is a superset of C<SVt_PV> and C<SVt_IV>.
72 C<SVt_PVNV> is similar.  C<SVt_PVMG> can hold anything C<SVt_PVNV> can hold, but it
73 can, but does not have to, be blessed or magical.
74 
75 =for apidoc AmnU||SVt_NULL
76 Type flag for scalars.  See L</svtype>.
77 
78 =for apidoc AmnU||SVt_IV
79 Type flag for scalars.  See L</svtype>.
80 
81 =for apidoc AmnU||SVt_NV
82 Type flag for scalars.  See L</svtype>.
83 
84 =for apidoc AmnU||SVt_PV
85 Type flag for scalars.  See L</svtype>.
86 
87 =for apidoc AmnU||SVt_PVIV
88 Type flag for scalars.  See L</svtype>.
89 
90 =for apidoc AmnU||SVt_PVNV
91 Type flag for scalars.  See L</svtype>.
92 
93 =for apidoc AmnU||SVt_PVMG
94 Type flag for scalars.  See L</svtype>.
95 
96 =for apidoc CmnU||SVt_INVLIST
97 Type flag for scalars.  See L<perlapi/svtype>.
98 
99 =for apidoc AmnU||SVt_REGEXP
100 Type flag for regular expressions.  See L</svtype>.
101 
102 =for apidoc AmnU||SVt_PVGV
103 Type flag for typeglobs.  See L</svtype>.
104 
105 =for apidoc AmnU||SVt_PVLV
106 Type flag for scalars.  See L</svtype>.
107 
108 =for apidoc AmnU||SVt_PVAV
109 Type flag for arrays.  See L</svtype>.
110 
111 =for apidoc AmnU||SVt_PVHV
112 Type flag for hashes.  See L</svtype>.
113 
114 =for apidoc AmnU||SVt_PVCV
115 Type flag for subroutines.  See L</svtype>.
116 
117 =for apidoc AmnU||SVt_PVFM
118 Type flag for formats.  See L</svtype>.
119 
120 =for apidoc AmnU||SVt_PVIO
121 Type flag for I/O objects.  See L</svtype>.
122 
123 =cut
124 
125   These are ordered so that the simpler types have a lower value; SvUPGRADE
126   doesn't allow you to upgrade from a higher numbered type to a lower numbered
127   one; also there is code that assumes that anything that has as a PV component
128   has a type numbered >= SVt_PV.
129 */
130 
131 
132 typedef enum {
133         SVt_NULL,	/* 0 */
134         /* BIND was here, before INVLIST replaced it.  */
135         SVt_IV,		/* 1 */
136         SVt_NV,		/* 2 */
137         /* RV was here, before it was merged with IV.  */
138         SVt_PV,		/* 3 */
139         SVt_INVLIST,	/* 4, implemented as a PV */
140         SVt_PVIV,	/* 5 */
141         SVt_PVNV,	/* 6 */
142         SVt_PVMG,	/* 7 */
143         SVt_REGEXP,	/* 8 */
144         /* PVBM was here, before BIND replaced it.  */
145         SVt_PVGV,	/* 9 */
146         SVt_PVLV,	/* 10 */
147         SVt_PVAV,	/* 11 */
148         SVt_PVHV,	/* 12 */
149         SVt_PVCV,	/* 13 */
150         SVt_PVFM,	/* 14 */
151         SVt_PVIO,	/* 15 */
152                         /* 16-31: Unused, though one should be reserved for a
153                          * freed sv, if the other 3 bits below the flags ones
154                          * get allocated */
155         SVt_LAST	/* keep last in enum. used to size arrays */
156 } svtype;
157 
158 /* *** any alterations to the SV types above need to be reflected in
159  * SVt_MASK and the various PL_valid_types_* tables.  As of this writing those
160  * tables are in perl.h.  There are also two affected names tables in dump.c,
161  * one in B.xs, and 'bodies_by_type[]' in sv.c.
162  *
163  * The bits that match 0xe0 are CURRENTLY UNUSED
164  * The bits above that are for flags, like SVf_IOK */
165 
166 #define SVt_MASK 0x1f	/* smallest bitmask that covers all types */
167 
168 #ifndef PERL_CORE
169 /* Fast Boyer Moore tables are now stored in magic attached to PVMGs */
170 #  define SVt_PVBM	SVt_PVMG
171 /* Anything wanting to create a reference from clean should ensure that it has
172    a scalar of type SVt_IV now:  */
173 #  define SVt_RV	SVt_IV
174 #endif
175 
176 /* The array of arena roots for SV bodies is indexed by SvTYPE. SVt_NULL doesn't
177  * use a body, so that arena root is re-used for HEs. SVt_IV also doesn't, so
178  * that arena root is used for HVs with struct xpvhv_aux. */
179 #if defined(PERL_IN_HV_C) || defined(PERL_IN_XS_APITEST)
180 #  define HE_ARENA_ROOT_IX      SVt_NULL
181 #endif
182 #if defined(PERL_IN_HV_C) || defined(PERL_IN_SV_C)
183 #  define HVAUX_ARENA_ROOT_IX   SVt_IV
184 #endif
185 #ifdef PERL_IN_SV_C
186 #  define SVt_FIRST SVt_NULL	/* the type of SV that new_SV() in sv.c returns */
187 #endif
188 
189 #define PERL_ARENA_ROOTS_SIZE	(SVt_LAST)
190 
191 /* typedefs to eliminate some typing */
192 typedef struct he HE;
193 typedef struct hek HEK;
194 
195 /* Using C's structural equivalence to help emulate C++ inheritance here... */
196 
197 /* start with 2 sv-head building blocks */
198 #define _SV_HEAD(ptrtype) \
199     ptrtype	sv_any;		/* pointer to body */	\
200     U32		sv_refcnt;	/* how many references to us */	\
201     U32		sv_flags	/* what we are */
202 
203 #if NVSIZE <= IVSIZE
204 #  define _NV_BODYLESS_UNION NV svu_nv;
205 #else
206 #  define _NV_BODYLESS_UNION
207 #endif
208 
209 #define _SV_HEAD_UNION \
210     union {				\
211         char*   svu_pv;		/* pointer to malloced string */	\
212         IV      svu_iv;			\
213         UV      svu_uv;			\
214         _NV_BODYLESS_UNION		\
215         SV*     svu_rv;		/* pointer to another SV */		\
216         SV**    svu_array;		\
217         HE**	svu_hash;		\
218         GP*	svu_gp;			\
219         PerlIO *svu_fp;			\
220     }	sv_u				\
221     _SV_HEAD_DEBUG
222 
223 #ifdef DEBUG_LEAKING_SCALARS
224 #define _SV_HEAD_DEBUG ;\
225     PERL_BITFIELD32 sv_debug_optype:9;	/* the type of OP that allocated us */ \
226     PERL_BITFIELD32 sv_debug_inpad:1;	/* was allocated in a pad for an OP */ \
227     PERL_BITFIELD32 sv_debug_line:16;	/* the line where we were allocated */ \
228     UV		    sv_debug_serial;	/* serial number of sv allocation   */ \
229     char *	    sv_debug_file;	/* the file where we were allocated */ \
230     SV *	    sv_debug_parent	/* what we were cloned from (ithreads)*/
231 #else
232 #define _SV_HEAD_DEBUG
233 #endif
234 
235 struct STRUCT_SV {		/* struct sv { */
236     _SV_HEAD(void*);
237     _SV_HEAD_UNION;
238 };
239 
240 struct gv {
241     _SV_HEAD(XPVGV*);		/* pointer to xpvgv body */
242     _SV_HEAD_UNION;
243 };
244 
245 struct cv {
246     _SV_HEAD(XPVCV*);		/* pointer to xpvcv body */
247     _SV_HEAD_UNION;
248 };
249 
250 struct av {
251     _SV_HEAD(XPVAV*);		/* pointer to xpvav body */
252     _SV_HEAD_UNION;
253 };
254 
255 struct hv {
256     _SV_HEAD(XPVHV*);		/* pointer to xpvhv body */
257     _SV_HEAD_UNION;
258 };
259 
260 struct io {
261     _SV_HEAD(XPVIO*);		/* pointer to xpvio body */
262     _SV_HEAD_UNION;
263 };
264 
265 struct p5rx {
266     _SV_HEAD(struct regexp*);	/* pointer to regexp body */
267     _SV_HEAD_UNION;
268 };
269 
270 struct invlist {
271     _SV_HEAD(XINVLIST*);       /* pointer to xpvinvlist body */
272     _SV_HEAD_UNION;
273 };
274 
275 #undef _SV_HEAD
276 #undef _SV_HEAD_UNION		/* ensure no pollution */
277 
278 /*
279 =for apidoc_section $SV
280 
281 =for apidoc Am|U32|SvREFCNT|SV* sv
282 Returns the value of the object's reference count. Exposed
283 to perl code via Internals::SvREFCNT().
284 
285 =for apidoc SvREFCNT_inc
286 =for apidoc_item SvREFCNT_inc_NN
287 =for apidoc_item SvREFCNT_inc_void
288 =for apidoc_item |void|SvREFCNT_inc_void_NN|SV* sv
289 =for apidoc_item |SV*|SvREFCNT_inc_simple|SV* sv
290 =for apidoc_item |SV*|SvREFCNT_inc_simple_NN|SV* sv
291 =for apidoc_item |void|SvREFCNT_inc_simple_void|SV* sv
292 =for apidoc_item |void|SvREFCNT_inc_simple_void_NN|SV* sv
293 
294 These all increment the reference count of the given SV.
295 The ones without C<void> in their names return the SV.
296 
297 C<SvREFCNT_inc> is the base operation; the rest are optimizations if various
298 input constraints are known to be true; hence, all can be replaced with
299 C<SvREFCNT_inc>.
300 
301 C<SvREFCNT_inc_NN> can only be used if you know C<sv> is not C<NULL>.  Since we
302 don't have to check the NULLness, it's faster and smaller.
303 
304 C<SvREFCNT_inc_void> can only be used if you don't need the
305 return value.  The macro doesn't need to return a meaningful value.
306 
307 C<SvREFCNT_inc_void_NN> can only be used if you both don't need the return
308 value, and you know that C<sv> is not C<NULL>.  The macro doesn't need to
309 return a meaningful value, or check for NULLness, so it's smaller and faster.
310 
311 C<SvREFCNT_inc_simple> can only be used with expressions without side
312 effects.  Since we don't have to store a temporary value, it's faster.
313 
314 C<SvREFCNT_inc_simple_NN> can only be used with expressions without side
315 effects and you know C<sv> is not C<NULL>.  Since we don't have to store a
316 temporary value, nor check for NULLness, it's faster and smaller.
317 
318 C<SvREFCNT_inc_simple_void> can only be used with expressions without side
319 effects and you don't need the return value.
320 
321 C<SvREFCNT_inc_simple_void_NN> can only be used with expressions without side
322 effects, you don't need the return value, and you know C<sv> is not C<NULL>.
323 
324 =for apidoc SvREFCNT_dec
325 =for apidoc_item SvREFCNT_dec_NN
326 
327 These decrement the reference count of the given SV.
328 
329 C<SvREFCNT_dec_NN> may only be used when C<sv> is known to not be C<NULL>.
330 
331 =for apidoc Am|svtype|SvTYPE|SV* sv
332 Returns the type of the SV.  See C<L</svtype>>.
333 
334 =for apidoc Am|void|SvUPGRADE|SV* sv|svtype type
335 Used to upgrade an SV to a more complex form.  Uses C<sv_upgrade> to
336 perform the upgrade if necessary.  See C<L</svtype>>.
337 
338 =cut
339 */
340 
341 #define SvANY(sv)	(sv)->sv_any
342 #define SvFLAGS(sv)	(sv)->sv_flags
343 #define SvREFCNT(sv)	(sv)->sv_refcnt
344 
345 #define SvREFCNT_inc(sv)		Perl_SvREFCNT_inc(MUTABLE_SV(sv))
346 #define SvREFCNT_inc_simple(sv)		SvREFCNT_inc(sv)
347 #define SvREFCNT_inc_NN(sv)		Perl_SvREFCNT_inc_NN(MUTABLE_SV(sv))
348 #define SvREFCNT_inc_void(sv)		Perl_SvREFCNT_inc_void(MUTABLE_SV(sv))
349 
350 /* These guys don't need the curly blocks */
351 #define SvREFCNT_inc_simple_void(sv)	STMT_START { if (sv) SvREFCNT(sv)++; } STMT_END
352 #define SvREFCNT_inc_simple_NN(sv)	(++(SvREFCNT(sv)),MUTABLE_SV(sv))
353 #define SvREFCNT_inc_void_NN(sv)	(void)(++SvREFCNT(MUTABLE_SV(sv)))
354 #define SvREFCNT_inc_simple_void_NN(sv)	(void)(++SvREFCNT(MUTABLE_SV(sv)))
355 
356 #define SvREFCNT_dec(sv)	Perl_SvREFCNT_dec(aTHX_ MUTABLE_SV(sv))
357 #define SvREFCNT_dec_NN(sv)	Perl_SvREFCNT_dec_NN(aTHX_ MUTABLE_SV(sv))
358 
359 #define SVTYPEMASK	0xff
360 #define SvTYPE(sv)	((svtype)((sv)->sv_flags & SVTYPEMASK))
361 
362 /* Sadly there are some parts of the core that have pointers to already-freed
363    SV heads, and rely on being able to tell that they are now free. So mark
364    them all by using a consistent macro.  */
365 #define SvIS_FREED(sv)	UNLIKELY(((sv)->sv_flags == SVTYPEMASK))
366 
367 /* this is defined in this peculiar way to avoid compiler warnings.
368  * See the <20121213131428.GD1842@iabyn.com> thread in p5p */
369 #define SvUPGRADE(sv, mt) \
370     ((void)(SvTYPE(sv) >= (mt) || (sv_upgrade(sv, mt),1)))
371 
372 #define SVf_IOK		0x00000100  /* has valid public integer value */
373 #define SVf_NOK		0x00000200  /* has valid public numeric value */
374 #define SVf_POK		0x00000400  /* has valid public pointer value */
375 #define SVf_ROK		0x00000800  /* has a valid reference pointer */
376 
377 #define SVp_IOK		0x00001000  /* has valid non-public integer value */
378 #define SVp_NOK		0x00002000  /* has valid non-public numeric value */
379 #define SVp_POK		0x00004000  /* has valid non-public pointer value */
380 #define SVp_SCREAM	0x00008000  /* currently unused on plain scalars */
381 #define SVphv_CLONEABLE	SVp_SCREAM  /* PVHV (stashes) clone its objects */
382 #define SVpgv_GP	SVp_SCREAM  /* GV has a valid GP */
383 #define SVprv_PCS_IMPORTED  SVp_SCREAM  /* RV is a proxy for a constant
384                                        subroutine in another package. Set the
385                                        GvIMPORTED_CV_on() if it needs to be
386                                        expanded to a real GV */
387 
388 /* SVf_PROTECT is what SVf_READONLY should have been: i.e. modifying
389  * this SV is completely illegal. However, SVf_READONLY (via
390  * Internals::SvREADONLY()) has come to be seen as a flag that can be
391  * temporarily set and unset by the user to indicate e.g. whether a hash
392  * is "locked". Now, Hash::Util et al only set SVf_READONLY, while core
393  * sets both (SVf_READONLY|SVf_PROTECT) to indicate both to core and user
394  * code that this SV should not be messed with.
395  */
396 #define SVf_PROTECT	0x00010000  /* very read-only */
397 #define SVs_PADTMP	0x00020000  /* in use as tmp */
398 #define SVs_PADSTALE	0x00040000  /* lexical has gone out of scope;
399                                         only used when !PADTMP */
400 #define SVs_TEMP	0x00080000  /* mortal (implies string is stealable) */
401 #define SVs_OBJECT	0x00100000  /* is "blessed" */
402 #define SVs_GMG		0x00200000  /* has magical get method */
403 #define SVs_SMG		0x00400000  /* has magical set method */
404 #define SVs_RMG		0x00800000  /* has random magical methods */
405 
406 #define SVf_FAKE	0x01000000  /* 0: glob is just a copy
407                                        1: SV head arena wasn't malloc()ed
408                                        2: For PVCV, whether CvUNIQUE(cv)
409                                           refers to an eval or once only
410                                           [CvEVAL(cv), CvSPECIAL(cv)]
411                                        3: HV: informally reserved by DAPM
412                                           for vtables
413                                        4: Together with other flags (or
414                                            lack thereof) indicates a regex,
415                                            including PVLV-as-regex. See
416                                            isREGEXP().
417                                        */
418 #define SVf_OOK		0x02000000  /* has valid offset value. For a PVHV this
419                                        means that a hv_aux struct is present
420                                        after the main array */
421 #define SVf_BREAK	0x04000000  /* refcnt is artificially low - used by
422                                        SVs in final arena cleanup.
423                                        Set in S_regtry on PL_reg_curpm, so that
424                                        perl_destruct will skip it.
425                                        Used for mark and sweep by OP_AASSIGN
426                                        */
427 #define SVf_READONLY	0x08000000  /* may not be modified */
428 
429 
430 
431 
432 #define SVf_THINKFIRST	(SVf_READONLY|SVf_PROTECT|SVf_ROK|SVf_FAKE \
433                         |SVs_RMG|SVf_IsCOW)
434 
435 #define SVf_OK		(SVf_IOK|SVf_NOK|SVf_POK|SVf_ROK| \
436                          SVp_IOK|SVp_NOK|SVp_POK|SVpgv_GP)
437 
438 #define PRIVSHIFT 4	/* (SVp_?OK >> PRIVSHIFT) == SVf_?OK */
439 
440 /* SVf_AMAGIC means that the stash *may* have overload methods. It's
441  * set each time a function is compiled into a stash, and is reset by the
442  * overload code when called for the first time and finds that there are
443  * no overload methods. Note that this used to be set on the object; but
444  * is now only set on stashes.
445  */
446 #define SVf_AMAGIC	0x10000000  /* has magical overloaded methods */
447 #define SVf_IsCOW	0x10000000  /* copy on write (shared hash key if
448                                        SvLEN == 0) */
449 
450 /* Ensure this value does not clash with the GV_ADD* flags in gv.h, or the
451    CV_CKPROTO_* flags in op.c, or the padadd_* flags in pad.h: */
452 #define SVf_UTF8        0x20000000  /* SvPV is UTF-8 encoded
453                                        This is also set on RVs whose overloaded
454                                        stringification is UTF-8. This might
455                                        only happen as a side effect of SvPV() */
456 /* PVHV */
457 #define SVphv_SHAREKEYS 0x20000000  /* PVHV keys live on shared string table */
458 
459 /* PVAV could probably use 0x2000000 without conflict. I assume that PVFM can
460    be UTF-8 encoded, and PVCVs could well have UTF-8 prototypes. PVIOs haven't
461    been restructured, so sometimes get used as string buffers.  */
462 
463 
464 /* Some private flags. */
465 
466 
467 /* scalar SVs with SVp_POK */
468 #define SVppv_STATIC    0x40000000 /* PV is pointer to static const; must be set with SVf_IsCOW */
469 /* PVAV */
470 #define SVpav_REAL	0x40000000  /* free old entries */
471 /* PVHV */
472 #define SVphv_LAZYDEL	0x40000000  /* entry in xhv_eiter must be deleted */
473 
474 /* IV, PVIV, PVNV, PVMG, PVGV and (I assume) PVLV  */
475 #define SVf_IVisUV	0x80000000  /* use XPVUV instead of XPVIV */
476 /* PVAV */
477 #define SVpav_REIFY 	0x80000000  /* can become real */
478 /* PVHV */
479 #define SVphv_HASKFLAGS	0x80000000  /* keys have flag byte after hash */
480 /* RV upwards. However, SVf_ROK and SVp_IOK are exclusive  */
481 #define SVprv_WEAKREF   0x80000000  /* Weak reference */
482 /* pad name vars only */
483 
484 #define _XPV_HEAD							\
485     HV*		xmg_stash;	/* class package */			\
486     union _xmgu	xmg_u;							\
487     STRLEN	xpv_cur;	/* length of svu_pv as a C string */    \
488     union {								\
489         STRLEN	xpvlenu_len; 	/* allocated size */			\
490         struct regexp* xpvlenu_rx; /* regex when SV body is XPVLV */    \
491     } xpv_len_u
492 
493 #define xpv_len	xpv_len_u.xpvlenu_len
494 
495 union _xnvu {
496     NV	    xnv_nv;		/* numeric value, if any */
497     HV *    xgv_stash;
498     line_t  xnv_lines;           /* used internally by S_scan_subst() */
499     bool    xnv_bm_tail;        /* an SvVALID (BM) SV has an implicit "\n" */
500 };
501 
502 union _xivu {
503     IV	    xivu_iv;		/* integer value */
504     UV	    xivu_uv;
505     HEK *   xivu_namehek;	/* xpvlv, xpvgv: GvNAME */
506     bool    xivu_eval_seen;     /* used internally by S_scan_subst() */
507 
508 };
509 
510 union _xmgu {
511     MAGIC*  xmg_magic;		/* linked list of magicalness */
512     STRLEN  xmg_hash_index;	/* used while freeing hash entries */
513 };
514 
515 struct xpv {
516     _XPV_HEAD;
517 };
518 
519 struct xpviv {
520     _XPV_HEAD;
521     union _xivu xiv_u;
522 };
523 
524 #define xiv_iv xiv_u.xivu_iv
525 
526 struct xpvuv {
527     _XPV_HEAD;
528     union _xivu xuv_u;
529 };
530 
531 #define xuv_uv xuv_u.xivu_uv
532 
533 struct xpvnv {
534     _XPV_HEAD;
535     union _xivu xiv_u;
536     union _xnvu xnv_u;
537 };
538 
539 /* This structure must match the beginning of struct xpvhv in hv.h. */
540 struct xpvmg {
541     _XPV_HEAD;
542     union _xivu xiv_u;
543     union _xnvu xnv_u;
544 };
545 
546 struct xpvlv {
547     _XPV_HEAD;
548     union _xivu xiv_u;
549     union _xnvu xnv_u;
550     union {
551         STRLEN	xlvu_targoff;
552         SSize_t xlvu_stargoff;
553     } xlv_targoff_u;
554     STRLEN	xlv_targlen;
555     SV*		xlv_targ;
556     char	xlv_type;	/* k=keys .=pos x=substr v=vec /=join/re
557                                  * y=alem/helem/iter t=tie T=tied HE */
558     char	xlv_flags;	/* 1 = negative offset  2 = negative len
559                                    4 = out of range (vec) */
560 };
561 
562 #define xlv_targoff xlv_targoff_u.xlvu_targoff
563 
564 struct xpvinvlist {
565     _XPV_HEAD;
566     IV          prev_index;     /* caches result of previous invlist_search() */
567     STRLEN	iterator;       /* Stores where we are in iterating */
568     bool	is_offset;	/* The data structure for all inversion lists
569                                    begins with an element for code point U+0000.
570                                    If this bool is set, the actual list contains
571                                    that 0; otherwise, the list actually begins
572                                    with the following element.  Thus to invert
573                                    the list, merely toggle this flag  */
574 };
575 
576 /* This structure works in 2 ways - regular scalar, or GV with GP */
577 
578 struct xpvgv {
579     _XPV_HEAD;
580     union _xivu xiv_u;
581     union _xnvu xnv_u;
582 };
583 
584 typedef U32 cv_flags_t;
585 
586 #define _XPVCV_COMMON								\
587     HV *	xcv_stash;							\
588     union {									\
589         OP *	xcv_start;							\
590         ANY	xcv_xsubany;							\
591     }		xcv_start_u;					    		\
592     union {									\
593         OP *	xcv_root;							\
594         void	(*xcv_xsub) (pTHX_ CV*);					\
595     }		xcv_root_u;							\
596     union {								\
597         GV *	xcv_gv;							\
598         HEK *	xcv_hek;						\
599     }		xcv_gv_u;						\
600     char *	xcv_file;							\
601     union {									\
602         PADLIST *	xcv_padlist;						\
603         void *		xcv_hscxt;						\
604     }		xcv_padlist_u;							\
605     CV *	xcv_outside;							\
606     U32		xcv_outside_seq; /* the COP sequence (at the point of our	\
607                                   * compilation) in the lexically enclosing	\
608                                   * sub */					\
609     cv_flags_t	xcv_flags;						\
610     I32	xcv_depth	/* >= 2 indicates recursive call */
611 
612 /* This structure must match XPVCV in cv.h */
613 
614 struct xpvfm {
615     _XPV_HEAD;
616     _XPVCV_COMMON;
617 };
618 
619 
620 struct xpvio {
621     _XPV_HEAD;
622     union _xivu xiv_u;
623     /* ifp and ofp are normally the same, but sockets need separate streams */
624     PerlIO *	xio_ofp;
625     /* Cray addresses everything by word boundaries (64 bits) and
626      * code and data pointers cannot be mixed (which is exactly what
627      * Perl_filter_add() tries to do with the dirp), hence the
628      *  following union trick (as suggested by Gurusamy Sarathy).
629      * For further information see Geir Johansen's problem report
630      * titled [ID 20000612.002 (#3366)] Perl problem on Cray system
631      * The any pointer (known as IoANY()) will also be a good place
632      * to hang any IO disciplines to.
633      */
634     union {
635         DIR *	xiou_dirp;	/* for opendir, readdir, etc */
636         void *	xiou_any;	/* for alignment */
637     } xio_dirpu;
638     /* IV xio_lines is now in IVX  $. */
639     IV		xio_page;	/* $% */
640     IV		xio_page_len;	/* $= */
641     IV		xio_lines_left;	/* $- */
642     char *	xio_top_name;	/* $^ */
643     GV *	xio_top_gv;	/* $^ */
644     char *	xio_fmt_name;	/* $~ */
645     GV *	xio_fmt_gv;	/* $~ */
646     char *	xio_bottom_name;/* $^B */
647     GV *	xio_bottom_gv;	/* $^B */
648     char	xio_type;
649     U8		xio_flags;
650 };
651 
652 #define xio_dirp	xio_dirpu.xiou_dirp
653 #define xio_any		xio_dirpu.xiou_any
654 
655 #define IOf_ARGV	1	/* this fp iterates over ARGV */
656 #define IOf_START	2	/* check for null ARGV and substitute '-' */
657 #define IOf_FLUSH	4	/* this fp wants a flush after write op */
658 #define IOf_DIDTOP	8	/* just did top of form */
659 #define IOf_UNTAINT	16	/* consider this fp (and its data) "safe" */
660 #define IOf_NOLINE	32	/* slurped a pseudo-line from empty file */
661 #define IOf_FAKE_DIRP	64	/* xio_dirp is fake (source filters kludge)
662                                    Also, when this is set, SvPVX() is valid */
663 
664 /* The following macros define implementation-independent predicates on SVs. */
665 
666 /*
667 =for apidoc Am|U32|SvNIOK|SV* sv
668 Returns a U32 value indicating whether the SV contains a number, integer or
669 double.
670 
671 =for apidoc Am|U32|SvNIOKp|SV* sv
672 Returns a U32 value indicating whether the SV contains a number, integer or
673 double.  Checks the B<private> setting.  Use C<SvNIOK> instead.
674 
675 =for apidoc Am|void|SvNIOK_off|SV* sv
676 Unsets the NV/IV status of an SV.
677 
678 =for apidoc Am|U32|SvOK|SV* sv
679 Returns a U32 value indicating whether the value is defined.  This is
680 only meaningful for scalars.
681 
682 =for apidoc Am|U32|SvIOKp|SV* sv
683 Returns a U32 value indicating whether the SV contains an integer.  Checks
684 the B<private> setting.  Use C<SvIOK> instead.
685 
686 =for apidoc Am|U32|SvNOKp|SV* sv
687 Returns a U32 value indicating whether the SV contains a double.  Checks the
688 B<private> setting.  Use C<SvNOK> instead.
689 
690 =for apidoc Am|U32|SvPOKp|SV* sv
691 Returns a U32 value indicating whether the SV contains a character string.
692 Checks the B<private> setting.  Use C<SvPOK> instead.
693 
694 =for apidoc Am|U32|SvIOK|SV* sv
695 Returns a U32 value indicating whether the SV contains an integer.
696 
697 =for apidoc Am|void|SvIOK_on|SV* sv
698 Tells an SV that it is an integer.
699 
700 =for apidoc Am|void|SvIOK_off|SV* sv
701 Unsets the IV status of an SV.
702 
703 =for apidoc Am|void|SvIOK_only|SV* sv
704 Tells an SV that it is an integer and disables all other C<OK> bits.
705 
706 =for apidoc Am|void|SvIOK_only_UV|SV* sv
707 Tells an SV that it is an unsigned integer and disables all other C<OK> bits.
708 
709 =for apidoc Am|bool|SvIOK_UV|SV* sv
710 Returns a boolean indicating whether the SV contains an integer that must be
711 interpreted as unsigned.  A non-negative integer whose value is within the
712 range of both an IV and a UV may be flagged as either C<SvUOK> or C<SvIOK>.
713 
714 =for apidoc Am|bool|SvUOK|SV* sv
715 Returns a boolean indicating whether the SV contains an integer that must be
716 interpreted as unsigned.  A non-negative integer whose value is within the
717 range of both an IV and a UV may be flagged as either C<SvUOK> or C<SvIOK>.
718 
719 =for apidoc Am|bool|SvIOK_notUV|SV* sv
720 Returns a boolean indicating whether the SV contains a signed integer.
721 
722 =for apidoc Am|U32|SvNOK|SV* sv
723 Returns a U32 value indicating whether the SV contains a double.
724 
725 =for apidoc Am|void|SvNOK_on|SV* sv
726 Tells an SV that it is a double.
727 
728 =for apidoc Am|void|SvNOK_off|SV* sv
729 Unsets the NV status of an SV.
730 
731 =for apidoc Am|void|SvNOK_only|SV* sv
732 Tells an SV that it is a double and disables all other OK bits.
733 
734 =for apidoc Am|U32|SvPOK|SV* sv
735 Returns a U32 value indicating whether the SV contains a character
736 string.
737 
738 =for apidoc Am|void|SvPOK_on|SV* sv
739 Tells an SV that it is a string.
740 
741 =for apidoc Am|void|SvPOK_off|SV* sv
742 Unsets the PV status of an SV.
743 
744 =for apidoc Am|void|SvPOK_only|SV* sv
745 Tells an SV that it is a string and disables all other C<OK> bits.
746 Will also turn off the UTF-8 status.
747 
748 =for apidoc Am|bool|SvVOK|SV* sv
749 Returns a boolean indicating whether the SV contains a v-string.
750 
751 =for apidoc Am|U32|SvOOK|SV* sv
752 Returns a U32 indicating whether the pointer to the string buffer is offset.
753 This hack is used internally to speed up removal of characters from the
754 beginning of a C<L</SvPV>>.  When C<SvOOK> is true, then the start of the
755 allocated string buffer is actually C<SvOOK_offset()> bytes before C<SvPVX>.
756 This offset used to be stored in C<SvIVX>, but is now stored within the spare
757 part of the buffer.
758 
759 =for apidoc Am|U32|SvROK|SV* sv
760 Tests if the SV is an RV.
761 
762 =for apidoc Am|void|SvROK_on|SV* sv
763 Tells an SV that it is an RV.
764 
765 =for apidoc Am|void|SvROK_off|SV* sv
766 Unsets the RV status of an SV.
767 
768 =for apidoc Am|SV*|SvRV|SV* sv
769 Dereferences an RV to return the SV.
770 
771 =for apidoc Am|IV|SvIVX|SV* sv
772 Returns the raw value in the SV's IV slot, without checks or conversions.
773 Only use when you are sure C<SvIOK> is true.  See also C<L</SvIV>>.
774 
775 =for apidoc Am|UV|SvUVX|SV* sv
776 Returns the raw value in the SV's UV slot, without checks or conversions.
777 Only use when you are sure C<SvIOK> is true.  See also C<L</SvUV>>.
778 
779 =for apidoc AmD|UV|SvUVXx|SV* sv
780 This is an unnecessary synonym for L</SvUVX>
781 
782 =for apidoc Am|NV|SvNVX|SV* sv
783 Returns the raw value in the SV's NV slot, without checks or conversions.
784 Only use when you are sure C<SvNOK> is true.  See also C<L</SvNV>>.
785 
786 =for apidoc Am|char*|SvPVX|SV* sv
787 =for apidoc_item |char*|SvPVXx|SV* sv
788 =for apidoc_item |const char*|SvPVX_const|SV* sv
789 =for apidoc_item |char*|SvPVX_mutable|SV* sv
790 
791 These return a pointer to the physical string in the SV.  The SV must contain a
792 string.  Prior to 5.9.3 it is not safe to execute these unless the SV's
793 type >= C<SVt_PV>.
794 
795 These are also used to store the name of an autoloaded subroutine in an XS
796 AUTOLOAD routine.  See L<perlguts/Autoloading with XSUBs>.
797 
798 C<SvPVXx> is identical to C<SvPVX>.
799 
800 C<SvPVX_mutable> is merely a synonym for C<SvPVX>, but its name emphasizes that
801 the string is modifiable by the caller.
802 
803 C<SvPVX_const> differs in that the return value has been cast so that the
804 compiler will complain if you were to try to modify the contents of the string,
805 (unless you cast away const yourself).
806 
807 =for apidoc Am|STRLEN|SvCUR|SV* sv
808 Returns the length, in bytes, of the PV inside the SV.
809 Note that this may not match Perl's C<length>; for that, use
810 C<sv_len_utf8(sv)>. See C<L</SvLEN>> also.
811 
812 =for apidoc Am|STRLEN|SvLEN|SV* sv
813 Returns the size of the string buffer in the SV, not including any part
814 attributable to C<SvOOK>.  See C<L</SvCUR>>.
815 
816 =for apidoc Am|char*|SvEND|SV* sv
817 Returns a pointer to the spot just after the last character in
818 the string which is in the SV, where there is usually a trailing
819 C<NUL> character (even though Perl scalars do not strictly require it).
820 See C<L</SvCUR>>.  Access the character as C<*(SvEND(sv))>.
821 
822 Warning: If C<SvCUR> is equal to C<SvLEN>, then C<SvEND> points to
823 unallocated memory.
824 
825 =for apidoc Am|HV*|SvSTASH|SV* sv
826 Returns the stash of the SV.
827 
828 =for apidoc Am|void|SvIV_set|SV* sv|IV val
829 Set the value of the IV pointer in sv to val.  It is possible to perform
830 the same function of this macro with an lvalue assignment to C<SvIVX>.
831 With future Perls, however, it will be more efficient to use
832 C<SvIV_set> instead of the lvalue assignment to C<SvIVX>.
833 
834 =for apidoc Am|void|SvNV_set|SV* sv|NV val
835 Set the value of the NV pointer in C<sv> to val.  See C<L</SvIV_set>>.
836 
837 =for apidoc Am|void|SvPV_set|SV* sv|char* val
838 This is probably not what you want to use, you probably wanted
839 L</sv_usepvn_flags> or L</sv_setpvn> or L</sv_setpvs>.
840 
841 Set the value of the PV pointer in C<sv> to the Perl allocated
842 C<NUL>-terminated string C<val>.  See also C<L</SvIV_set>>.
843 
844 Remember to free the previous PV buffer. There are many things to check.
845 Beware that the existing pointer may be involved in copy-on-write or other
846 mischief, so do C<SvOOK_off(sv)> and use C<sv_force_normal> or
847 C<SvPV_force> (or check the C<SvIsCOW> flag) first to make sure this
848 modification is safe. Then finally, if it is not a COW, call
849 C<L</SvPV_free>> to free the previous PV buffer.
850 
851 =for apidoc Am|void|SvUV_set|SV* sv|UV val
852 Set the value of the UV pointer in C<sv> to val.  See C<L</SvIV_set>>.
853 
854 =for apidoc Am|void|SvRV_set|SV* sv|SV* val
855 Set the value of the RV pointer in C<sv> to val.  See C<L</SvIV_set>>.
856 
857 =for apidoc Am|void|SvMAGIC_set|SV* sv|MAGIC* val
858 Set the value of the MAGIC pointer in C<sv> to val.  See C<L</SvIV_set>>.
859 
860 =for apidoc Am|void|SvSTASH_set|SV* sv|HV* val
861 Set the value of the STASH pointer in C<sv> to val.  See C<L</SvIV_set>>.
862 
863 =for apidoc Am|void|SvCUR_set|SV* sv|STRLEN len
864 Sets the current length, in bytes, of the C string which is in the SV.
865 See C<L</SvCUR>> and C<SvIV_set>>.
866 
867 =for apidoc Am|void|SvLEN_set|SV* sv|STRLEN len
868 Set the size of the string buffer for the SV. See C<L</SvLEN>>.
869 
870 =cut
871 */
872 
873 #define SvNIOK(sv)		(SvFLAGS(sv) & (SVf_IOK|SVf_NOK))
874 #define SvNIOKp(sv)		(SvFLAGS(sv) & (SVp_IOK|SVp_NOK))
875 #define SvNIOK_off(sv)		(SvFLAGS(sv) &= ~(SVf_IOK|SVf_NOK| \
876                                                   SVp_IOK|SVp_NOK|SVf_IVisUV))
877 
878 #define assert_not_ROK(sv)	assert_(!SvROK(sv) || !SvRV(sv))
879 #define assert_not_glob(sv)	assert_(!isGV_with_GP(sv))
880 
881 #define SvOK(sv)		(SvFLAGS(sv) & SVf_OK)
882 #define SvOK_off(sv)		(assert_not_ROK(sv) assert_not_glob(sv)	\
883                                  SvFLAGS(sv) &=	~(SVf_OK|		\
884                                                   SVf_IVisUV|SVf_UTF8),	\
885                                                         SvOOK_off(sv))
886 #define SvOK_off_exc_UV(sv)	(assert_not_ROK(sv)			\
887                                  SvFLAGS(sv) &=	~(SVf_OK|		\
888                                                   SVf_UTF8),		\
889                                                         SvOOK_off(sv))
890 
891 #define SvOKp(sv)		(SvFLAGS(sv) & (SVp_IOK|SVp_NOK|SVp_POK))
892 #define SvIOKp(sv)		(SvFLAGS(sv) & SVp_IOK)
893 #define SvIOKp_on(sv)		(assert_not_glob(sv)	\
894                                     SvFLAGS(sv) |= SVp_IOK)
895 #define SvNOKp(sv)		(SvFLAGS(sv) & SVp_NOK)
896 #define SvNOKp_on(sv)		(assert_not_glob(sv) SvFLAGS(sv) |= SVp_NOK)
897 #define SvPOKp(sv)		(SvFLAGS(sv) & SVp_POK)
898 #define SvPOKp_on(sv)		(assert_not_ROK(sv) assert_not_glob(sv)	\
899                                  SvFLAGS(sv) |= SVp_POK)
900 
901 #define SvIOK(sv)		(SvFLAGS(sv) & SVf_IOK)
902 #define SvIOK_on(sv)		(assert_not_glob(sv)	\
903                                     SvFLAGS(sv) |= (SVf_IOK|SVp_IOK))
904 #define SvIOK_off(sv)		(SvFLAGS(sv) &= ~(SVf_IOK|SVp_IOK|SVf_IVisUV))
905 #define SvIOK_only(sv)		(SvOK_off(sv), \
906                                     SvFLAGS(sv) |= (SVf_IOK|SVp_IOK))
907 #define SvIOK_only_UV(sv)	(assert_not_glob(sv) SvOK_off_exc_UV(sv), \
908                                     SvFLAGS(sv) |= (SVf_IOK|SVp_IOK))
909 
910 #define SvIOK_UV(sv)		((SvFLAGS(sv) & (SVf_IOK|SVf_IVisUV))	\
911                                  == (SVf_IOK|SVf_IVisUV))
912 #define SvUOK(sv)		SvIOK_UV(sv)
913 #define SvIOK_notUV(sv)		((SvFLAGS(sv) & (SVf_IOK|SVf_IVisUV))	\
914                                  == SVf_IOK)
915 
916 #define SvIsUV(sv)		(SvFLAGS(sv) & SVf_IVisUV)
917 #define SvIsUV_on(sv)		(SvFLAGS(sv) |= SVf_IVisUV)
918 #define SvIsUV_off(sv)		(SvFLAGS(sv) &= ~SVf_IVisUV)
919 
920 #define SvNOK(sv)		(SvFLAGS(sv) & SVf_NOK)
921 #define SvNOK_on(sv)		(assert_not_glob(sv) \
922                                  SvFLAGS(sv) |= (SVf_NOK|SVp_NOK))
923 #define SvNOK_off(sv)		(SvFLAGS(sv) &= ~(SVf_NOK|SVp_NOK))
924 #define SvNOK_only(sv)		(SvOK_off(sv), \
925                                     SvFLAGS(sv) |= (SVf_NOK|SVp_NOK))
926 
927 /*
928 =for apidoc Am|U32|SvUTF8|SV* sv
929 Returns a U32 value indicating the UTF-8 status of an SV.  If things are set-up
930 properly, this indicates whether or not the SV contains UTF-8 encoded data.
931 You should use this I<after> a call to C<L</SvPV>> or one of its variants, in
932 case any call to string overloading updates the internal flag.
933 
934 If you want to take into account the L<bytes> pragma, use C<L</DO_UTF8>>
935 instead.
936 
937 =for apidoc Am|void|SvUTF8_on|SV *sv
938 Turn on the UTF-8 status of an SV (the data is not changed, just the flag).
939 Do not use frivolously.
940 
941 =for apidoc Am|void|SvUTF8_off|SV *sv
942 Unsets the UTF-8 status of an SV (the data is not changed, just the flag).
943 Do not use frivolously.
944 
945 =for apidoc Am|void|SvPOK_only_UTF8|SV* sv
946 Tells an SV that it is a string and disables all other C<OK> bits,
947 and leaves the UTF-8 status as it was.
948 
949 =cut
950  */
951 
952 /* Ensure the return value of this macro does not clash with the GV_ADD* flags
953 in gv.h: */
954 #define SvUTF8(sv)		(SvFLAGS(sv) & SVf_UTF8)
955 #define SvUTF8_on(sv)		(SvFLAGS(sv) |= (SVf_UTF8))
956 #define SvUTF8_off(sv)		(SvFLAGS(sv) &= ~(SVf_UTF8))
957 
958 #define SvPOK(sv)		(SvFLAGS(sv) & SVf_POK)
959 #define SvPOK_on(sv)		(assert_not_ROK(sv) assert_not_glob(sv)	\
960                                  SvFLAGS(sv) |= (SVf_POK|SVp_POK))
961 #define SvPOK_off(sv)		(SvFLAGS(sv) &= ~(SVf_POK|SVp_POK))
962 #define SvPOK_only(sv)		(assert_not_ROK(sv) assert_not_glob(sv)	\
963                                  SvFLAGS(sv) &= ~(SVf_OK|		\
964                                                   SVf_IVisUV|SVf_UTF8),	\
965                                     SvFLAGS(sv) |= (SVf_POK|SVp_POK))
966 #define SvPOK_only_UTF8(sv)	(assert_not_ROK(sv) assert_not_glob(sv)	\
967                                  SvFLAGS(sv) &= ~(SVf_OK|		\
968                                                   SVf_IVisUV),		\
969                                     SvFLAGS(sv) |= (SVf_POK|SVp_POK))
970 
971 #define SvVOK(sv)		(SvMAGICAL(sv)				\
972                                  && mg_find(sv,PERL_MAGIC_vstring))
973 /*
974 =for apidoc Am|MAGIC*|SvVSTRING_mg|SV * sv
975 
976 Returns the vstring magic, or NULL if none
977 
978 =cut
979 */
980 #define SvVSTRING_mg(sv)	(SvMAGICAL(sv) \
981                                  ? mg_find(sv,PERL_MAGIC_vstring) : NULL)
982 
983 #define SvOOK(sv)		(SvFLAGS(sv) & SVf_OOK)
984 #define SvOOK_on(sv)		(SvFLAGS(sv) |= SVf_OOK)
985 
986 
987 /*
988 =for apidoc Am|void|SvOOK_off|SV * sv
989 
990 Remove any string offset.
991 
992 =cut
993 */
994 
995 #define SvOOK_off(sv)		((void)(SvOOK(sv) && (sv_backoff(sv),0)))
996 
997 #define SvFAKE(sv)		(SvFLAGS(sv) & SVf_FAKE)
998 #define SvFAKE_on(sv)		(SvFLAGS(sv) |= SVf_FAKE)
999 #define SvFAKE_off(sv)		(SvFLAGS(sv) &= ~SVf_FAKE)
1000 
1001 #define SvROK(sv)		(SvFLAGS(sv) & SVf_ROK)
1002 #define SvROK_on(sv)		(SvFLAGS(sv) |= SVf_ROK)
1003 #define SvROK_off(sv)		(SvFLAGS(sv) &= ~(SVf_ROK))
1004 
1005 #define SvMAGICAL(sv)		(SvFLAGS(sv) & (SVs_GMG|SVs_SMG|SVs_RMG))
1006 #define SvMAGICAL_on(sv)	(SvFLAGS(sv) |= (SVs_GMG|SVs_SMG|SVs_RMG))
1007 #define SvMAGICAL_off(sv)	(SvFLAGS(sv) &= ~(SVs_GMG|SVs_SMG|SVs_RMG))
1008 
1009 #define SvGMAGICAL(sv)		(SvFLAGS(sv) & SVs_GMG)
1010 #define SvGMAGICAL_on(sv)	(SvFLAGS(sv) |= SVs_GMG)
1011 #define SvGMAGICAL_off(sv)	(SvFLAGS(sv) &= ~SVs_GMG)
1012 
1013 #define SvSMAGICAL(sv)		(SvFLAGS(sv) & SVs_SMG)
1014 #define SvSMAGICAL_on(sv)	(SvFLAGS(sv) |= SVs_SMG)
1015 #define SvSMAGICAL_off(sv)	(SvFLAGS(sv) &= ~SVs_SMG)
1016 
1017 #define SvRMAGICAL(sv)		(SvFLAGS(sv) & SVs_RMG)
1018 #define SvRMAGICAL_on(sv)	(SvFLAGS(sv) |= SVs_RMG)
1019 #define SvRMAGICAL_off(sv)	(SvFLAGS(sv) &= ~SVs_RMG)
1020 
1021 #define SvAMAGIC(sv)		(SvROK(sv) && SvOBJECT(SvRV(sv)) &&	\
1022                                  HvAMAGIC(SvSTASH(SvRV(sv))))
1023 
1024 /* To be used on the stashes themselves: */
1025 #define HvAMAGIC(hv)		(SvFLAGS(hv) & SVf_AMAGIC)
1026 #define HvAMAGIC_on(hv)		(SvFLAGS(hv) |= SVf_AMAGIC)
1027 #define HvAMAGIC_off(hv)	(SvFLAGS(hv) &=~ SVf_AMAGIC)
1028 
1029 
1030 /* "nog" means "doesn't have get magic" */
1031 #define SvPOK_nog(sv)		((SvFLAGS(sv) & (SVf_POK|SVs_GMG)) == SVf_POK)
1032 #define SvIOK_nog(sv)		((SvFLAGS(sv) & (SVf_IOK|SVs_GMG)) == SVf_IOK)
1033 #define SvUOK_nog(sv)		((SvFLAGS(sv) & (SVf_IOK|SVf_IVisUV|SVs_GMG)) == (SVf_IOK|SVf_IVisUV))
1034 #define SvNOK_nog(sv)		((SvFLAGS(sv) & (SVf_NOK|SVs_GMG)) == SVf_NOK)
1035 #define SvNIOK_nog(sv)		(SvNIOK(sv) && !(SvFLAGS(sv) & SVs_GMG))
1036 
1037 #define SvPOK_nogthink(sv)	((SvFLAGS(sv) & (SVf_POK|SVf_THINKFIRST|SVs_GMG)) == SVf_POK)
1038 #define SvIOK_nogthink(sv)	((SvFLAGS(sv) & (SVf_IOK|SVf_THINKFIRST|SVs_GMG)) == SVf_IOK)
1039 #define SvUOK_nogthink(sv)	((SvFLAGS(sv) & (SVf_IOK|SVf_IVisUV|SVf_THINKFIRST|SVs_GMG)) == (SVf_IOK|SVf_IVisUV))
1040 #define SvNOK_nogthink(sv)	((SvFLAGS(sv) & (SVf_NOK|SVf_THINKFIRST|SVs_GMG)) == SVf_NOK)
1041 #define SvNIOK_nogthink(sv)	(SvNIOK(sv) && !(SvFLAGS(sv) & (SVf_THINKFIRST|SVs_GMG)))
1042 
1043 #define SvPOK_utf8_nog(sv)	((SvFLAGS(sv) & (SVf_POK|SVf_UTF8|SVs_GMG)) == (SVf_POK|SVf_UTF8))
1044 #define SvPOK_utf8_nogthink(sv)	((SvFLAGS(sv) & (SVf_POK|SVf_UTF8|SVf_THINKFIRST|SVs_GMG)) == (SVf_POK|SVf_UTF8))
1045 
1046 #define SvPOK_byte_nog(sv)	((SvFLAGS(sv) & (SVf_POK|SVf_UTF8|SVs_GMG)) == SVf_POK)
1047 #define SvPOK_byte_nogthink(sv)	((SvFLAGS(sv) & (SVf_POK|SVf_UTF8|SVf_THINKFIRST|SVs_GMG)) == SVf_POK)
1048 
1049 #define SvPOK_pure_nogthink(sv) \
1050     ((SvFLAGS(sv) & (SVf_POK|SVf_IOK|SVf_NOK|SVf_ROK|SVpgv_GP|SVf_THINKFIRST|SVs_GMG)) == SVf_POK)
1051 #define SvPOK_utf8_pure_nogthink(sv) \
1052     ((SvFLAGS(sv) & (SVf_POK|SVf_UTF8|SVf_IOK|SVf_NOK|SVf_ROK|SVpgv_GP|SVf_THINKFIRST|SVs_GMG)) == (SVf_POK|SVf_UTF8))
1053 #define SvPOK_byte_pure_nogthink(sv) \
1054     ((SvFLAGS(sv) & (SVf_POK|SVf_UTF8|SVf_IOK|SVf_NOK|SVf_ROK|SVpgv_GP|SVf_THINKFIRST|SVs_GMG)) == SVf_POK)
1055 
1056 /*
1057 =for apidoc Am|bool|SvIsBOOL|SV* sv
1058 
1059 Returns true if the SV is one of the special boolean constants (PL_sv_yes or
1060 PL_sv_no), or is a regular SV whose last assignment stored a copy of one.
1061 
1062 =cut
1063 */
1064 
1065 #define SvIsBOOL(sv)            Perl_sv_isbool(aTHX_ sv)
1066 
1067 /*
1068 =for apidoc Am|U32|SvGAMAGIC|SV* sv
1069 
1070 Returns true if the SV has get magic or
1071 overloading.  If either is true then
1072 the scalar is active data, and has the potential to return a new value every
1073 time it is accessed.  Hence you must be careful to
1074 only read it once per user logical operation and work
1075 with that returned value.  If neither is true then
1076 the scalar's value cannot change unless written to.
1077 
1078 =cut
1079 */
1080 
1081 #define SvGAMAGIC(sv)           (SvGMAGICAL(sv) || SvAMAGIC(sv))
1082 
1083 #define Gv_AMG(stash) \
1084         (HvNAME(stash) && Gv_AMupdate(stash,FALSE) \
1085             ? 1					    \
1086             : (HvAMAGIC_off(stash), 0))
1087 
1088 #define SvWEAKREF(sv)		((SvFLAGS(sv) & (SVf_ROK|SVprv_WEAKREF)) \
1089                                   == (SVf_ROK|SVprv_WEAKREF))
1090 #define SvWEAKREF_on(sv)	(SvFLAGS(sv) |=  (SVf_ROK|SVprv_WEAKREF))
1091 #define SvWEAKREF_off(sv)	(SvFLAGS(sv) &= ~(SVf_ROK|SVprv_WEAKREF))
1092 
1093 #define SvPCS_IMPORTED(sv)	((SvFLAGS(sv) & (SVf_ROK|SVprv_PCS_IMPORTED)) \
1094                                  == (SVf_ROK|SVprv_PCS_IMPORTED))
1095 #define SvPCS_IMPORTED_on(sv)	(SvFLAGS(sv) |=  (SVf_ROK|SVprv_PCS_IMPORTED))
1096 #define SvPCS_IMPORTED_off(sv)	(SvFLAGS(sv) &= ~(SVf_ROK|SVprv_PCS_IMPORTED))
1097 
1098 /*
1099 =for apidoc m|U32|SvTHINKFIRST|SV *sv
1100 
1101 A quick flag check to see whether an C<sv> should be passed to C<sv_force_normal>
1102 to be "downgraded" before C<SvIVX> or C<SvPVX> can be modified directly.
1103 
1104 For example, if your scalar is a reference and you want to modify the C<SvIVX>
1105 slot, you can't just do C<SvROK_off>, as that will leak the referent.
1106 
1107 This is used internally by various sv-modifying functions, such as
1108 C<sv_setsv>, C<sv_setiv> and C<sv_pvn_force>.
1109 
1110 One case that this does not handle is a gv without SvFAKE set.  After
1111 
1112     if (SvTHINKFIRST(gv)) sv_force_normal(gv);
1113 
1114 it will still be a gv.
1115 
1116 C<SvTHINKFIRST> sometimes produces false positives.  In those cases
1117 C<sv_force_normal> does nothing.
1118 
1119 =cut
1120 */
1121 
1122 #define SvTHINKFIRST(sv)	(SvFLAGS(sv) & SVf_THINKFIRST)
1123 
1124 #define SVs_PADMY		0
1125 #define SvPADMY(sv)		!(SvFLAGS(sv) & SVs_PADTMP)
1126 #ifndef PERL_CORE
1127 # define SvPADMY_on(sv)		SvPADTMP_off(sv)
1128 #endif
1129 
1130 #define SvPADTMP(sv)		(SvFLAGS(sv) & (SVs_PADTMP))
1131 #define SvPADSTALE(sv)		(SvFLAGS(sv) & (SVs_PADSTALE))
1132 
1133 #define SvPADTMP_on(sv)		(SvFLAGS(sv) |= SVs_PADTMP)
1134 #define SvPADTMP_off(sv)	(SvFLAGS(sv) &= ~SVs_PADTMP)
1135 #define SvPADSTALE_on(sv)	Perl_SvPADSTALE_on(MUTABLE_SV(sv))
1136 #define SvPADSTALE_off(sv)	Perl_SvPADSTALE_off(MUTABLE_SV(sv))
1137 
1138 #define SvTEMP(sv)		(SvFLAGS(sv) & SVs_TEMP)
1139 #define SvTEMP_on(sv)		(SvFLAGS(sv) |= SVs_TEMP)
1140 #define SvTEMP_off(sv)		(SvFLAGS(sv) &= ~SVs_TEMP)
1141 
1142 #define SvOBJECT(sv)		(SvFLAGS(sv) & SVs_OBJECT)
1143 #define SvOBJECT_on(sv)		(SvFLAGS(sv) |= SVs_OBJECT)
1144 #define SvOBJECT_off(sv)	(SvFLAGS(sv) &= ~SVs_OBJECT)
1145 
1146 /*
1147 =for apidoc Am|U32|SvREADONLY|SV* sv
1148 Returns true if the argument is readonly, otherwise returns false.
1149 Exposed to perl code via Internals::SvREADONLY().
1150 
1151 =for apidoc Am|U32|SvREADONLY_on|SV* sv
1152 Mark an object as readonly. Exactly what this means depends on the object
1153 type. Exposed to perl code via Internals::SvREADONLY().
1154 
1155 =for apidoc Am|U32|SvREADONLY_off|SV* sv
1156 Mark an object as not-readonly. Exactly what this mean depends on the
1157 object type. Exposed to perl code via Internals::SvREADONLY().
1158 
1159 =cut
1160 */
1161 
1162 #define SvREADONLY(sv)		(SvFLAGS(sv) & (SVf_READONLY|SVf_PROTECT))
1163 #ifdef PERL_CORE
1164 # define SvREADONLY_on(sv)	(SvFLAGS(sv) |= (SVf_READONLY|SVf_PROTECT))
1165 # define SvREADONLY_off(sv)	(SvFLAGS(sv) &=~(SVf_READONLY|SVf_PROTECT))
1166 #else
1167 # define SvREADONLY_on(sv)	(SvFLAGS(sv) |= SVf_READONLY)
1168 # define SvREADONLY_off(sv)	(SvFLAGS(sv) &= ~SVf_READONLY)
1169 #endif
1170 
1171 #define SvSCREAM(sv) ((SvFLAGS(sv) & (SVp_SCREAM|SVp_POK)) == (SVp_SCREAM|SVp_POK))
1172 #define SvSCREAM_on(sv)		(SvFLAGS(sv) |= SVp_SCREAM)
1173 #define SvSCREAM_off(sv)	(SvFLAGS(sv) &= ~SVp_SCREAM)
1174 
1175 #ifndef PERL_CORE
1176 #  define SvCOMPILED(sv)	0
1177 #  define SvCOMPILED_on(sv)
1178 #  define SvCOMPILED_off(sv)
1179 #endif
1180 
1181 
1182 #if defined (DEBUGGING) && defined(PERL_USE_GCC_BRACE_GROUPS)
1183 #  define SvTAIL(sv)	({ const SV *const _svtail = (const SV *)(sv);	\
1184                             assert(SvTYPE(_svtail) != SVt_PVAV);	\
1185                             assert(SvTYPE(_svtail) != SVt_PVHV);	\
1186                             assert(!(SvFLAGS(_svtail) & (SVf_NOK|SVp_NOK))); \
1187                             assert(SvVALID(_svtail));                        \
1188                             ((XPVNV*)SvANY(_svtail))->xnv_u.xnv_bm_tail;     \
1189                         })
1190 #else
1191 #  define SvTAIL(_svtail)  (((XPVNV*)SvANY(_svtail))->xnv_u.xnv_bm_tail)
1192 #endif
1193 
1194 /* Does the SV have a Boyer-Moore table attached as magic?
1195  * 'VALID' is a poor name, but is kept for historical reasons.  */
1196 #define SvVALID(_svvalid) (                                  \
1197                SvPOKp(_svvalid)                              \
1198             && SvSMAGICAL(_svvalid)                          \
1199             && SvMAGIC(_svvalid)                             \
1200             && (SvMAGIC(_svvalid)->mg_type == PERL_MAGIC_bm  \
1201                 || mg_find(_svvalid, PERL_MAGIC_bm))         \
1202         )
1203 
1204 #define SvRVx(sv) SvRV(sv)
1205 
1206 #ifdef PERL_DEBUG_COW
1207 /* Need -0.0 for SvNVX to preserve IEEE FP "negative zero" because
1208    +0.0 + -0.0 => +0.0 but -0.0 + -0.0 => -0.0 */
1209 #  define SvIVX(sv) (0 + ((XPVIV*) SvANY(sv))->xiv_iv)
1210 #  define SvUVX(sv) (0 + ((XPVUV*) SvANY(sv))->xuv_uv)
1211 #  define SvNVX(sv) (-0.0 + ((XPVNV*) SvANY(sv))->xnv_u.xnv_nv)
1212 #  define SvRV(sv) (0 + (sv)->sv_u.svu_rv)
1213 #  define SvRV_const(sv) (0 + (sv)->sv_u.svu_rv)
1214 /* Don't test the core XS code yet.  */
1215 #  if defined (PERL_CORE) && PERL_DEBUG_COW > 1
1216 #    define SvPVX(sv) (0 + (assert_(!SvREADONLY(sv)) (sv)->sv_u.svu_pv))
1217 #  else
1218 #  define SvPVX(sv) SvPVX_mutable(sv)
1219 #  endif
1220 #  define SvCUR(sv) (0 + ((XPV*) SvANY(sv))->xpv_cur)
1221 #  define SvLEN(sv) (0 + ((XPV*) SvANY(sv))->xpv_len)
1222 #  define SvEND(sv) ((sv)->sv_u.svu_pv + ((XPV*)SvANY(sv))->xpv_cur)
1223 
1224 #  define SvMAGIC(sv)	(0 + *(assert_(SvTYPE(sv) >= SVt_PVMG) &((XPVMG*)  SvANY(sv))->xmg_u.xmg_magic))
1225 #  define SvSTASH(sv)	(0 + *(assert_(SvTYPE(sv) >= SVt_PVMG) &((XPVMG*)  SvANY(sv))->xmg_stash))
1226 #else   /* Below is not PERL_DEBUG_COW */
1227 # ifdef PERL_CORE
1228 #  define SvLEN(sv) (0 + ((XPV*) SvANY(sv))->xpv_len)
1229 # else
1230 #  define SvLEN(sv) ((XPV*) SvANY(sv))->xpv_len
1231 # endif
1232 #  define SvEND(sv) ((sv)->sv_u.svu_pv + ((XPV*)SvANY(sv))->xpv_cur)
1233 
1234 #  if defined (DEBUGGING) && defined(PERL_USE_GCC_BRACE_GROUPS)
1235 /* These get expanded inside other macros that already use a variable _sv  */
1236 #    define SvPVX(sv)							\
1237         (*({ SV *const _svpvx = MUTABLE_SV(sv);				\
1238             assert(PL_valid_types_PVX[SvTYPE(_svpvx) & SVt_MASK]);	\
1239             assert(!isGV_with_GP(_svpvx));				\
1240             assert(!(SvTYPE(_svpvx) == SVt_PVIO				\
1241                      && !(IoFLAGS(_svpvx) & IOf_FAKE_DIRP)));		\
1242             &((_svpvx)->sv_u.svu_pv);					\
1243          }))
1244 #   ifdef PERL_CORE
1245 #    define SvCUR(sv)							\
1246         ({ const SV *const _svcur = (const SV *)(sv);			\
1247             assert(PL_valid_types_PVX[SvTYPE(_svcur) & SVt_MASK]);	\
1248             assert(!isGV_with_GP(_svcur));				\
1249             assert(!(SvTYPE(_svcur) == SVt_PVIO				\
1250                      && !(IoFLAGS(_svcur) & IOf_FAKE_DIRP)));		\
1251             (((XPV*) MUTABLE_PTR(SvANY(_svcur)))->xpv_cur);		\
1252          })
1253 #   else
1254 #    define SvCUR(sv)							\
1255         (*({ const SV *const _svcur = (const SV *)(sv);			\
1256             assert(PL_valid_types_PVX[SvTYPE(_svcur) & SVt_MASK]);	\
1257             assert(!isGV_with_GP(_svcur));				\
1258             assert(!(SvTYPE(_svcur) == SVt_PVIO				\
1259                      && !(IoFLAGS(_svcur) & IOf_FAKE_DIRP)));		\
1260             &(((XPV*) MUTABLE_PTR(SvANY(_svcur)))->xpv_cur);		\
1261          }))
1262 #   endif
1263 #    define SvIVX(sv)							\
1264         (*({ const SV *const _svivx = (const SV *)(sv);			\
1265             assert(PL_valid_types_IVX[SvTYPE(_svivx) & SVt_MASK]);	\
1266             assert(!isGV_with_GP(_svivx));				\
1267             &(((XPVIV*) MUTABLE_PTR(SvANY(_svivx)))->xiv_iv);		\
1268          }))
1269 #    define SvUVX(sv)							\
1270         (*({ const SV *const _svuvx = (const SV *)(sv);			\
1271             assert(PL_valid_types_IVX[SvTYPE(_svuvx) & SVt_MASK]);	\
1272             assert(!isGV_with_GP(_svuvx));				\
1273             &(((XPVUV*) MUTABLE_PTR(SvANY(_svuvx)))->xuv_uv);		\
1274          }))
1275 #    define SvNVX(sv)							\
1276         (*({ const SV *const _svnvx = (const SV *)(sv);			\
1277             assert(PL_valid_types_NVX[SvTYPE(_svnvx) & SVt_MASK]);	\
1278             assert(!isGV_with_GP(_svnvx));				\
1279             &(((XPVNV*) MUTABLE_PTR(SvANY(_svnvx)))->xnv_u.xnv_nv);	\
1280          }))
1281 #    define SvRV(sv)							\
1282         (*({ SV *const _svrv = MUTABLE_SV(sv);				\
1283             assert(PL_valid_types_RV[SvTYPE(_svrv) & SVt_MASK]);	\
1284             assert(!isGV_with_GP(_svrv));				\
1285             assert(!(SvTYPE(_svrv) == SVt_PVIO				\
1286                      && !(IoFLAGS(_svrv) & IOf_FAKE_DIRP)));		\
1287             &((_svrv)->sv_u.svu_rv);					\
1288          }))
1289 #    define SvRV_const(sv)						\
1290         ({ const SV *const _svrv = (const SV *)(sv);			\
1291             assert(PL_valid_types_RV[SvTYPE(_svrv) & SVt_MASK]);	\
1292             assert(!isGV_with_GP(_svrv));				\
1293             assert(!(SvTYPE(_svrv) == SVt_PVIO				\
1294                      && !(IoFLAGS(_svrv) & IOf_FAKE_DIRP)));		\
1295             (_svrv)->sv_u.svu_rv;					\
1296          })
1297 #    define SvMAGIC(sv)							\
1298         (*({ const SV *const _svmagic = (const SV *)(sv);		\
1299             assert(SvTYPE(_svmagic) >= SVt_PVMG);			\
1300             &(((XPVMG*) MUTABLE_PTR(SvANY(_svmagic)))->xmg_u.xmg_magic); \
1301           }))
1302 #    define SvSTASH(sv)							\
1303         (*({ const SV *const _svstash = (const SV *)(sv);		\
1304             assert(SvTYPE(_svstash) >= SVt_PVMG);			\
1305             &(((XPVMG*) MUTABLE_PTR(SvANY(_svstash)))->xmg_stash);	\
1306           }))
1307 #  else     /* Below is not DEBUGGING or can't use brace groups */
1308 #    define SvPVX(sv) ((sv)->sv_u.svu_pv)
1309 #    define SvCUR(sv) ((XPV*) SvANY(sv))->xpv_cur
1310 #    define SvIVX(sv) ((XPVIV*) SvANY(sv))->xiv_iv
1311 #    define SvUVX(sv) ((XPVUV*) SvANY(sv))->xuv_uv
1312 #    define SvNVX(sv) ((XPVNV*) SvANY(sv))->xnv_u.xnv_nv
1313 #    define SvRV(sv) ((sv)->sv_u.svu_rv)
1314 #    define SvRV_const(sv) (0 + (sv)->sv_u.svu_rv)
1315 #    define SvMAGIC(sv)	((XPVMG*)  SvANY(sv))->xmg_u.xmg_magic
1316 #    define SvSTASH(sv)	((XPVMG*)  SvANY(sv))->xmg_stash
1317 #  endif
1318 #endif
1319 
1320 #ifndef PERL_POISON
1321 /* Given that these two are new, there can't be any existing code using them
1322  *  as LVALUEs, so prevent that from happening  */
1323 #  define SvPVX_mutable(sv)	(0 + (sv)->sv_u.svu_pv)
1324 #  define SvPVX_const(sv)	((const char*)(0 + (sv)->sv_u.svu_pv))
1325 #else
1326 /* Except for the poison code, which uses & to scribble over the pointer after
1327    free() is called.  */
1328 #  define SvPVX_mutable(sv)	((sv)->sv_u.svu_pv)
1329 #  define SvPVX_const(sv)	((const char*)((sv)->sv_u.svu_pv))
1330 #endif
1331 
1332 #define SvIVXx(sv) SvIVX(sv)
1333 #define SvUVXx(sv) SvUVX(sv)
1334 #define SvNVXx(sv) SvNVX(sv)
1335 #define SvPVXx(sv) SvPVX(sv)
1336 #define SvLENx(sv) SvLEN(sv)
1337 #define SvENDx(sv) ((PL_Sv = (sv)), SvEND(PL_Sv))
1338 
1339 
1340 /* Ask a scalar nicely to try to become an IV, if possible.
1341    Not guaranteed to stay returning void */
1342 /* Macro won't actually call sv_2iv if already IOK */
1343 #define SvIV_please(sv) \
1344         STMT_START {if (!SvIOKp(sv) && (SvFLAGS(sv) & (SVf_NOK|SVf_POK))) \
1345                 (void) SvIV(sv); } STMT_END
1346 #define SvIV_please_nomg(sv) \
1347         (!(SvFLAGS(sv) & (SVf_IOK|SVp_IOK)) && (SvFLAGS(sv) & (SVf_NOK|SVf_POK)) \
1348             ? (sv_2iv_flags(sv, 0), SvIOK(sv))	  \
1349             : SvIOK(sv))
1350 #define SvIV_set(sv, val) \
1351         STMT_START { \
1352                 assert(PL_valid_types_IV_set[SvTYPE(sv) & SVt_MASK]);	\
1353                 assert(!isGV_with_GP(sv));		\
1354                 (((XPVIV*)  SvANY(sv))->xiv_iv = (val)); } STMT_END
1355 #define SvNV_set(sv, val) \
1356         STMT_START { \
1357                 assert(PL_valid_types_NV_set[SvTYPE(sv) & SVt_MASK]);	\
1358                 assert(!isGV_with_GP(sv));		\
1359                 (((XPVNV*)SvANY(sv))->xnv_u.xnv_nv = (val)); } STMT_END
1360 #define SvPV_set(sv, val) \
1361         STMT_START { \
1362                 assert(PL_valid_types_PVX[SvTYPE(sv) & SVt_MASK]);	\
1363                 assert(!isGV_with_GP(sv));		\
1364                 assert(!(SvTYPE(sv) == SVt_PVIO		\
1365                      && !(IoFLAGS(sv) & IOf_FAKE_DIRP))); \
1366                 ((sv)->sv_u.svu_pv = (val)); } STMT_END
1367 #define SvUV_set(sv, val) \
1368         STMT_START { \
1369                 assert(PL_valid_types_IV_set[SvTYPE(sv) & SVt_MASK]);	\
1370                 assert(!isGV_with_GP(sv));		\
1371                 (((XPVUV*)SvANY(sv))->xuv_uv = (val)); } STMT_END
1372 #define SvRV_set(sv, val) \
1373         STMT_START { \
1374                 assert(PL_valid_types_RV[SvTYPE(sv) & SVt_MASK]);	\
1375                 assert(!isGV_with_GP(sv));		\
1376                 assert(!(SvTYPE(sv) == SVt_PVIO		\
1377                      && !(IoFLAGS(sv) & IOf_FAKE_DIRP))); \
1378                 ((sv)->sv_u.svu_rv = (val)); } STMT_END
1379 #define SvMAGIC_set(sv, val) \
1380         STMT_START { assert(SvTYPE(sv) >= SVt_PVMG); \
1381                 (((XPVMG*)SvANY(sv))->xmg_u.xmg_magic = (val)); } STMT_END
1382 #define SvSTASH_set(sv, val) \
1383         STMT_START { assert(SvTYPE(sv) >= SVt_PVMG); \
1384                 (((XPVMG*)  SvANY(sv))->xmg_stash = (val)); } STMT_END
1385 #define SvCUR_set(sv, val) \
1386         STMT_START { \
1387                 assert(PL_valid_types_PVX[SvTYPE(sv) & SVt_MASK]);	\
1388                 assert(!isGV_with_GP(sv));		\
1389                 assert(!(SvTYPE(sv) == SVt_PVIO		\
1390                      && !(IoFLAGS(sv) & IOf_FAKE_DIRP))); \
1391                 (((XPV*)  SvANY(sv))->xpv_cur = (val)); } STMT_END
1392 #define SvLEN_set(sv, val) \
1393         STMT_START { \
1394                 assert(PL_valid_types_PVX[SvTYPE(sv) & SVt_MASK]);	\
1395                 assert(!isGV_with_GP(sv));	\
1396                 assert(!(SvTYPE(sv) == SVt_PVIO		\
1397                      && !(IoFLAGS(sv) & IOf_FAKE_DIRP))); \
1398                 (((XPV*)  SvANY(sv))->xpv_len = (val)); } STMT_END
1399 #define SvEND_set(sv, val) \
1400         STMT_START { assert(SvTYPE(sv) >= SVt_PV); \
1401                 SvCUR_set(sv, (val) - SvPVX(sv)); } STMT_END
1402 
1403 /*
1404 =for apidoc Am|void|SvPV_renew|SV* sv|STRLEN len
1405 Low level micro optimization of C<L</SvGROW>>.  It is generally better to use
1406 C<SvGROW> instead.  This is because C<SvPV_renew> ignores potential issues that
1407 C<SvGROW> handles.  C<sv> needs to have a real C<PV> that is unencombered by
1408 things like COW.  Using C<SV_CHECK_THINKFIRST> or
1409 C<SV_CHECK_THINKFIRST_COW_DROP> before calling this should clean it up, but
1410 why not just use C<SvGROW> if you're not sure about the provenance?
1411 
1412 =cut
1413 */
1414 #define SvPV_renew(sv,n) \
1415         STMT_START { SvLEN_set(sv, n); \
1416                 SvPV_set((sv), (MEM_WRAP_CHECK_(n,char)			\
1417                                 (char*)saferealloc((Malloc_t)SvPVX(sv), \
1418                                                    (MEM_SIZE)((n)))));  \
1419                  } STMT_END
1420 
1421 #define SvPV_shrink_to_cur(sv) STMT_START { \
1422                    const STRLEN _lEnGtH = SvCUR(sv) + 1; \
1423                    SvPV_renew(sv, _lEnGtH); \
1424                  } STMT_END
1425 
1426 /*
1427 =for apidoc Am|void|SvPV_free|SV * sv
1428 
1429 Frees the PV buffer in C<sv>, leaving things in a precarious state, so should
1430 only be used as part of a larger operation
1431 
1432 =cut
1433 */
1434 #define SvPV_free(sv)							\
1435     STMT_START {							\
1436                      assert(SvTYPE(sv) >= SVt_PV);			\
1437                      if (SvLEN(sv)) {					\
1438                          assert(!SvROK(sv));				\
1439                          if(UNLIKELY(SvOOK(sv))) {			\
1440                              STRLEN zok; 				\
1441                              SvOOK_offset(sv, zok);			\
1442                              SvPV_set(sv, SvPVX_mutable(sv) - zok);	\
1443                              SvFLAGS(sv) &= ~SVf_OOK;			\
1444                          }						\
1445                          Safefree(SvPVX(sv));				\
1446                      }							\
1447                  } STMT_END
1448 
1449 #ifdef PERL_CORE
1450 /* Code that crops up in three places to take a scalar and ready it to hold
1451    a reference */
1452 #  define prepare_SV_for_RV(sv)						\
1453     STMT_START {							\
1454                     if (SvTYPE(sv) < SVt_PV && SvTYPE(sv) != SVt_IV)	\
1455                         sv_upgrade(sv, SVt_IV);				\
1456                     else if (SvTYPE(sv) >= SVt_PV) {			\
1457                         SvPV_free(sv);					\
1458                         SvLEN_set(sv, 0);				\
1459                         SvCUR_set(sv, 0);				\
1460                     }							\
1461                  } STMT_END
1462 #endif
1463 
1464 #ifndef PERL_CORE
1465 #  define BmFLAGS(sv)		(SvTAIL(sv) ? FBMcf_TAIL : 0)
1466 #endif
1467 
1468 #if defined (DEBUGGING) && defined(PERL_USE_GCC_BRACE_GROUPS)
1469 #  define BmUSEFUL(sv)							\
1470         (*({ SV *const _bmuseful = MUTABLE_SV(sv);			\
1471             assert(SvTYPE(_bmuseful) >= SVt_PVIV);			\
1472             assert(SvVALID(_bmuseful));					\
1473             assert(!SvIOK(_bmuseful));					\
1474             &(((XPVIV*) SvANY(_bmuseful))->xiv_u.xivu_iv);              \
1475          }))
1476 #else
1477 #  define BmUSEFUL(sv)          ((XPVIV*) SvANY(sv))->xiv_u.xivu_iv
1478 
1479 #endif
1480 
1481 #ifndef PERL_CORE
1482 # define BmRARE(sv)	0
1483 # define BmPREVIOUS(sv)	0
1484 #endif
1485 
1486 #define FmLINES(sv)	((XPVIV*)  SvANY(sv))->xiv_iv
1487 
1488 #define LvTYPE(sv)	((XPVLV*)  SvANY(sv))->xlv_type
1489 #define LvTARG(sv)	((XPVLV*)  SvANY(sv))->xlv_targ
1490 #define LvTARGOFF(sv)	((XPVLV*)  SvANY(sv))->xlv_targoff
1491 #define LvSTARGOFF(sv)	((XPVLV*)  SvANY(sv))->xlv_targoff_u.xlvu_stargoff
1492 #define LvTARGLEN(sv)	((XPVLV*)  SvANY(sv))->xlv_targlen
1493 #define LvFLAGS(sv)	((XPVLV*)  SvANY(sv))->xlv_flags
1494 
1495 #define LVf_NEG_OFF      0x1
1496 #define LVf_NEG_LEN      0x2
1497 #define LVf_OUT_OF_RANGE 0x4
1498 
1499 #define IoIFP(sv)	(sv)->sv_u.svu_fp
1500 #define IoOFP(sv)	((XPVIO*)  SvANY(sv))->xio_ofp
1501 #define IoDIRP(sv)	((XPVIO*)  SvANY(sv))->xio_dirp
1502 #define IoANY(sv)	((XPVIO*)  SvANY(sv))->xio_any
1503 #define IoLINES(sv)	((XPVIO*)  SvANY(sv))->xiv_u.xivu_iv
1504 #define IoPAGE(sv)	((XPVIO*)  SvANY(sv))->xio_page
1505 #define IoPAGE_LEN(sv)	((XPVIO*)  SvANY(sv))->xio_page_len
1506 #define IoLINES_LEFT(sv)((XPVIO*)  SvANY(sv))->xio_lines_left
1507 #define IoTOP_NAME(sv)	((XPVIO*)  SvANY(sv))->xio_top_name
1508 #define IoTOP_GV(sv)	((XPVIO*)  SvANY(sv))->xio_top_gv
1509 #define IoFMT_NAME(sv)	((XPVIO*)  SvANY(sv))->xio_fmt_name
1510 #define IoFMT_GV(sv)	((XPVIO*)  SvANY(sv))->xio_fmt_gv
1511 #define IoBOTTOM_NAME(sv)((XPVIO*) SvANY(sv))->xio_bottom_name
1512 #define IoBOTTOM_GV(sv)	((XPVIO*)  SvANY(sv))->xio_bottom_gv
1513 #define IoTYPE(sv)	((XPVIO*)  SvANY(sv))->xio_type
1514 #define IoFLAGS(sv)	((XPVIO*)  SvANY(sv))->xio_flags
1515 
1516 /* IoTYPE(sv) is a single character telling the type of I/O connection. */
1517 #define IoTYPE_RDONLY		'<'
1518 #define IoTYPE_WRONLY		'>'
1519 #define IoTYPE_RDWR		'+'
1520 #define IoTYPE_APPEND 		'a'
1521 #define IoTYPE_PIPE		'|'
1522 #define IoTYPE_STD		'-'	/* stdin or stdout */
1523 #define IoTYPE_SOCKET		's'
1524 #define IoTYPE_CLOSED		' '
1525 #define IoTYPE_IMPLICIT		'I'	/* stdin or stdout or stderr */
1526 #define IoTYPE_NUMERIC		'#'	/* fdopen */
1527 
1528 /*
1529 =for apidoc Am|bool|SvTAINTED|SV* sv
1530 Checks to see if an SV is tainted.  Returns TRUE if it is, FALSE if
1531 not.
1532 
1533 =for apidoc Am|void|SvTAINTED_on|SV* sv
1534 Marks an SV as tainted if tainting is enabled.
1535 
1536 =for apidoc Am|void|SvTAINTED_off|SV* sv
1537 Untaints an SV.  Be I<very> careful with this routine, as it short-circuits
1538 some of Perl's fundamental security features.  XS module authors should not
1539 use this function unless they fully understand all the implications of
1540 unconditionally untainting the value.  Untainting should be done in the
1541 standard perl fashion, via a carefully crafted regexp, rather than directly
1542 untainting variables.
1543 
1544 =for apidoc Am|void|SvTAINT|SV* sv
1545 Taints an SV if tainting is enabled, and if some input to the current
1546 expression is tainted--usually a variable, but possibly also implicit
1547 inputs such as locale settings.  C<SvTAINT> propagates that taintedness to
1548 the outputs of an expression in a pessimistic fashion; i.e., without paying
1549 attention to precisely which outputs are influenced by which inputs.
1550 
1551 =cut
1552 */
1553 
1554 #define sv_taint(sv)	  sv_magic((sv), NULL, PERL_MAGIC_taint, NULL, 0)
1555 
1556 #ifdef NO_TAINT_SUPPORT
1557 #   define SvTAINTED(sv) 0
1558 #else
1559 #   define SvTAINTED(sv)	  (SvMAGICAL(sv) && sv_tainted(sv))
1560 #endif
1561 #define SvTAINTED_on(sv)  STMT_START{ if(UNLIKELY(TAINTING_get)){sv_taint(sv);}   }STMT_END
1562 #define SvTAINTED_off(sv) STMT_START{ if(UNLIKELY(TAINTING_get)){sv_untaint(sv);} }STMT_END
1563 
1564 #define SvTAINT(sv)			\
1565     STMT_START {			\
1566         assert(TAINTING_get || !TAINT_get); \
1567         if (UNLIKELY(TAINT_get))	\
1568             SvTAINTED_on(sv);	        \
1569     } STMT_END
1570 
1571 /*
1572 =for apidoc Am|char*|SvPV_force|SV* sv|STRLEN len
1573 =for apidoc_item ||SvPV_force_nolen|SV* sv
1574 =for apidoc_item ||SvPVx_force|SV* sv|STRLEN len
1575 =for apidoc_item ||SvPV_force_nomg|SV* sv|STRLEN len
1576 =for apidoc_item ||SvPV_force_nomg_nolen|SV * sv
1577 =for apidoc_item ||SvPV_force_mutable|SV * sv|STRLEN len
1578 =for apidoc_item ||SvPV_force_flags|SV * sv|STRLEN len|U32 flags
1579 =for apidoc_item ||SvPV_force_flags_nolen|SV * sv|U32 flags
1580 =for apidoc_item ||SvPV_force_flags_mutable|SV * sv|STRLEN len|U32 flags
1581 =for apidoc_item ||SvPVbyte_force
1582 =for apidoc_item ||SvPVbytex_force
1583 =for apidoc_item ||SvPVutf8_force
1584 =for apidoc_item ||SvPVutf8x_force
1585 
1586 These are like C<L</SvPV>>, returning the string in the SV, but will force the
1587 SV into containing a string (C<L</SvPOK>>), and only a string
1588 (C<L</SvPOK_only>>), by hook or by crook.  You need to use one of these
1589 C<force> routines if you are going to update the C<L</SvPVX>> directly.
1590 
1591 Note that coercing an arbitrary scalar into a plain PV will potentially
1592 strip useful data from it.  For example if the SV was C<SvROK>, then the
1593 referent will have its reference count decremented, and the SV itself may
1594 be converted to an C<SvPOK> scalar with a string buffer containing a value
1595 such as C<"ARRAY(0x1234)">.
1596 
1597 The differences between the forms are:
1598 
1599 The forms with C<flags> in their names allow you to use the C<flags> parameter
1600 to specify to perform 'get' magic (by setting the C<SV_GMAGIC> flag) or to skip
1601 'get' magic (by clearing it).  The other forms do perform 'get' magic, except
1602 for the ones with C<nomg> in their names, which skip 'get' magic.
1603 
1604 The forms that take a C<len> parameter will set that variable to the byte
1605 length of the resultant string (these are macros, so don't use C<&len>).
1606 
1607 The forms with C<nolen> in their names indicate they don't have a C<len>
1608 parameter.  They should be used only when it is known that the PV is a C
1609 string, terminated by a NUL byte, and without intermediate NUL characters; or
1610 when you don't care about its length.
1611 
1612 The forms with C<mutable> in their names are effectively the same as those without,
1613 but the name emphasizes that the string is modifiable by the caller, which it is
1614 in all the forms.
1615 
1616 C<SvPVutf8_force> is like C<SvPV_force>, but converts C<sv> to UTF-8 first if
1617 not already UTF-8.
1618 
1619 C<SvPVutf8x_force> is like C<SvPVutf8_force>, but guarantees to evaluate C<sv>
1620 only once; use the more efficient C<SvPVutf8_force> otherwise.
1621 
1622 C<SvPVbyte_force> is like C<SvPV_force>, but converts C<sv> to byte
1623 representation first if currently encoded as UTF-8.  If the SV cannot be
1624 downgraded from UTF-8, this croaks.
1625 
1626 C<SvPVbytex_force> is like C<SvPVbyte_force>, but guarantees to evaluate C<sv>
1627 only once; use the more efficient C<SvPVbyte_force> otherwise.
1628 
1629 =for apidoc Am|char*|SvPV|SV* sv|STRLEN len
1630 =for apidoc_item |char*|SvPVx|SV* sv|STRLEN len
1631 =for apidoc_item |char*|SvPV_nomg|SV* sv|STRLEN len
1632 =for apidoc_item |char*|SvPV_nolen|SV* sv
1633 =for apidoc_item |char*|SvPVx_nolen|SV* sv
1634 =for apidoc_item |char*|SvPV_nomg_nolen|SV* sv
1635 =for apidoc_item |char*|SvPV_mutable|SV* sv|STRLEN len
1636 =for apidoc_item |const char*|SvPV_const|SV* sv|STRLEN len
1637 =for apidoc_item |const char*|SvPVx_const|SV* sv|STRLEN len
1638 =for apidoc_item |const char*|SvPV_nolen_const|SV* sv
1639 =for apidoc_item |const char*|SvPVx_nolen_const|SV* sv
1640 =for apidoc_item |const char*|SvPV_nomg_const|SV* sv|STRLEN len
1641 =for apidoc_item |const char*|SvPV_nomg_const_nolen|SV* sv
1642 =for apidoc_item |char *|SvPV_flags|SV * sv|STRLEN len|U32 flags
1643 =for apidoc_item |const char *|SvPV_flags_const|SV * sv|STRLEN len|U32 flags
1644 =for apidoc_item |char *|SvPV_flags_mutable|SV * sv|STRLEN len|U32 flags
1645 =for apidoc_item |char*|SvPVbyte|SV* sv|STRLEN len
1646 =for apidoc_item |char*|SvPVbyte_nomg|SV* sv|STRLEN len
1647 =for apidoc_item |char*|SvPVbyte_nolen|SV* sv
1648 =for apidoc_item |char*|SvPVbytex_nolen|SV* sv
1649 =for apidoc_item |char*|SvPVbytex|SV* sv|STRLEN len
1650 =for apidoc_item |char*|SvPVbyte_or_null|SV* sv|STRLEN len
1651 =for apidoc_item |char*|SvPVbyte_or_null_nomg|SV* sv|STRLEN len
1652 =for apidoc_item |char*|SvPVutf8|SV* sv|STRLEN len
1653 =for apidoc_item |char*|SvPVutf8x|SV* sv|STRLEN len
1654 =for apidoc_item |char*|SvPVutf8_nomg|SV* sv|STRLEN len
1655 =for apidoc_item |char*|SvPVutf8_nolen|SV* sv
1656 =for apidoc_item |char*|SvPVutf8_or_null|SV* sv|STRLEN len
1657 =for apidoc_item |char*|SvPVutf8_or_null_nomg|SV* sv|STRLEN len
1658 
1659 All these return a pointer to the string in C<sv>, or a stringified form of
1660 C<sv> if it does not contain a string.  The SV may cache the stringified
1661 version becoming C<SvPOK>.
1662 
1663 This is a very basic and common operation, so there are lots of slightly
1664 different versions of it.
1665 
1666 Note that there is no guarantee that the return value of C<SvPV(sv)>, for
1667 example, is equal to C<SvPVX(sv)>, or that C<SvPVX(sv)> contains valid data, or
1668 that successive calls to C<SvPV(sv)> (or another of these forms) will return
1669 the same pointer value each time.  This is due to the way that things like
1670 overloading and Copy-On-Write are handled.  In these cases, the return value
1671 may point to a temporary buffer or similar.  If you absolutely need the
1672 C<SvPVX> field to be valid (for example, if you intend to write to it), then
1673 see C<L</SvPV_force>>.
1674 
1675 The differences between the forms are:
1676 
1677 The forms with neither C<byte> nor C<utf8> in their names (e.g., C<SvPV> or
1678 C<SvPV_nolen>) can expose the SV's internal string buffer. If
1679 that buffer consists entirely of bytes 0-255 and includes any bytes above
1680 127, then you B<MUST> consult C<SvUTF8> to determine the actual code points
1681 the string is meant to contain. Generally speaking, it is probably safer to
1682 prefer C<SvPVbyte>, C<SvPVutf8>, and the like. See
1683 L<perlguts/How do I pass a Perl string to a C library?> for more details.
1684 
1685 The forms with C<flags> in their names allow you to use the C<flags> parameter
1686 to specify to process 'get' magic (by setting the C<SV_GMAGIC> flag) or to skip
1687 'get' magic (by clearing it).  The other forms process 'get' magic, except for
1688 the ones with C<nomg> in their names, which skip 'get' magic.
1689 
1690 The forms that take a C<len> parameter will set that variable to the byte
1691 length of the resultant string (these are macros, so don't use C<&len>).
1692 
1693 The forms with C<nolen> in their names indicate they don't have a C<len>
1694 parameter.  They should be used only when it is known that the PV is a C
1695 string, terminated by a NUL byte, and without intermediate NUL characters; or
1696 when you don't care about its length.
1697 
1698 The forms with C<const> in their names return S<C<const char *>> so that the
1699 compiler will hopefully complain if you were to try to modify the contents of
1700 the string (unless you cast away const yourself).
1701 
1702 The other forms return a mutable pointer so that the string is modifiable by
1703 the caller; this is emphasized for the ones with C<mutable> in their names.
1704 
1705 The forms whose name ends in C<x> are the same as the corresponding form
1706 without the C<x>, but the C<x> form is guaranteed to evaluate C<sv> exactly
1707 once, with a slight loss of efficiency.  Use this if C<sv> is an expression
1708 with side effects.
1709 
1710 C<SvPVutf8> is like C<SvPV>, but converts C<sv> to UTF-8 first if not already
1711 UTF-8.  Similiarly, the other forms with C<utf8> in their names correspond to
1712 their respective forms without.
1713 
1714 C<SvPVutf8_or_null> and C<SvPVutf8_or_null_nomg> don't have corresponding
1715 non-C<utf8> forms.  Instead they are like C<SvPVutf8_nomg>, but when C<sv> is
1716 undef, they return C<NULL>.
1717 
1718 C<SvPVbyte> is like C<SvPV>, but converts C<sv> to byte representation first if
1719 currently encoded as UTF-8.  If C<sv> cannot be downgraded from UTF-8, it
1720 croaks.  Similiarly, the other forms with C<byte> in their names correspond to
1721 their respective forms without.
1722 
1723 C<SvPVbyte_or_null> doesn't have a corresponding non-C<byte> form.  Instead it
1724 is like C<SvPVbyte>, but when C<sv> is undef, it returns C<NULL>.
1725 
1726 =for apidoc Am|IV|SvIV|SV* sv
1727 =for apidoc_item SvIVx
1728 =for apidoc_item SvIV_nomg
1729 
1730 These coerce the given SV to IV and return it.  The returned value in many
1731 circumstances will get stored in C<sv>'s IV slot, but not in all cases.  (Use
1732 C<L</sv_setiv>> to make sure it does).
1733 
1734 C<SvIVx> is different from the others in that it is guaranteed to evaluate
1735 C<sv> exactly once; the others may evaluate it multiple times.  Only use this
1736 form if C<sv> is an expression with side effects, otherwise use the more
1737 efficient C<SvIV>.
1738 
1739 C<SvIV_nomg> is the same as C<SvIV>, but does not perform 'get' magic.
1740 
1741 =for apidoc Am|NV|SvNV|SV* sv
1742 =for apidoc_item SvNVx
1743 =for apidoc_item SvNV_nomg
1744 
1745 These coerce the given SV to NV and return it.  The returned value in many
1746 circumstances will get stored in C<sv>'s NV slot, but not in all cases.  (Use
1747 C<L</sv_setnv>> to make sure it does).
1748 
1749 C<SvNVx> is different from the others in that it is guaranteed to evaluate
1750 C<sv> exactly once; the others may evaluate it multiple times.  Only use this
1751 form if C<sv> is an expression with side effects, otherwise use the more
1752 efficient C<SvNV>.
1753 
1754 C<SvNV_nomg> is the same as C<SvNV>, but does not perform 'get' magic.
1755 
1756 =for apidoc Am|UV|SvUV|SV* sv
1757 =for apidoc_item SvUVx
1758 =for apidoc_item SvUV_nomg
1759 
1760 These coerce the given SV to UV and return it.  The returned value in many
1761 circumstances will get stored in C<sv>'s UV slot, but not in all cases.  (Use
1762 C<L</sv_setuv>> to make sure it does).
1763 
1764 C<SvUVx> is different from the others in that it is guaranteed to evaluate
1765 C<sv> exactly once; the others may evaluate it multiple times.  Only use this
1766 form if C<sv> is an expression with side effects, otherwise use the more
1767 efficient C<SvUV>.
1768 
1769 C<SvUV_nomg> is the same as C<SvUV>, but does not perform 'get' magic.
1770 
1771 =for apidoc SvTRUE
1772 =for apidoc_item SvTRUEx
1773 =for apidoc_item SvTRUE_nomg
1774 =for apidoc_item SvTRUE_NN
1775 =for apidoc_item SvTRUE_nomg_NN
1776 
1777 These return a boolean indicating whether Perl would evaluate the SV as true or
1778 false.  See C<L</SvOK>> for a defined/undefined test.
1779 
1780 As of Perl 5.32, all are guaranteed to evaluate C<sv> only once.  Prior to that
1781 release, only C<SvTRUEx> guaranteed single evaluation; now C<SvTRUEx> is
1782 identical to C<SvTRUE>.
1783 
1784 C<SvTRUE_nomg> and C<TRUE_nomg_NN> do not perform 'get' magic; the others do
1785 unless the scalar is already C<SvPOK>, C<SvIOK>, or C<SvNOK> (the public, not
1786 the private flags).
1787 
1788 C<SvTRUE_NN> is like C<L</SvTRUE>>, but C<sv> is assumed to be
1789 non-null (NN).  If there is a possibility that it is NULL, use plain
1790 C<SvTRUE>.
1791 
1792 C<SvTRUE_nomg_NN> is like C<L</SvTRUE_nomg>>, but C<sv> is assumed to be
1793 non-null (NN).  If there is a possibility that it is NULL, use plain
1794 C<SvTRUE_nomg>.
1795 
1796 =for apidoc Am|char*|SvPVutf8_force|SV* sv|STRLEN len
1797 Like C<SvPV_force>, but converts C<sv> to UTF-8 first if necessary.
1798 
1799 =for apidoc Am|char*|SvPVutf8|SV* sv|STRLEN len
1800 Like C<SvPV>, but converts C<sv> to UTF-8 first if necessary.
1801 
1802 =for apidoc Am|char*|SvPVutf8_nomg|SV* sv|STRLEN len
1803 Like C<SvPVutf8>, but does not process get magic.
1804 
1805 =for apidoc Am|char*|SvPVutf8_or_null|SV* sv|STRLEN len
1806 Like C<SvPVutf8>, but when C<sv> is undef, returns C<NULL>.
1807 
1808 =for apidoc Am|char*|SvPVutf8_or_null_nomg|SV* sv|STRLEN len
1809 Like C<SvPVutf8_or_null>, but does not process get magic.
1810 
1811 =for apidoc Am|char*|SvPVutf8_nolen|SV* sv
1812 Like C<SvPV_nolen>, but converts C<sv> to UTF-8 first if necessary.
1813 
1814 =for apidoc Am|char*|SvPVbyte_force|SV* sv|STRLEN len
1815 Like C<SvPV_force>, but converts C<sv> to byte representation first if
1816 necessary.  If the SV cannot be downgraded from UTF-8, this croaks.
1817 
1818 =for apidoc Am|char*|SvPVbyte|SV* sv|STRLEN len
1819 Like C<SvPV>, but converts C<sv> to byte representation first if necessary.  If
1820 the SV cannot be downgraded from UTF-8, this croaks.
1821 
1822 =for apidoc Am|char*|SvPVbyte_nomg|SV* sv|STRLEN len
1823 Like C<SvPVbyte>, but does not process get magic.
1824 
1825 =for apidoc Am|char*|SvPVbyte_or_null|SV* sv|STRLEN len
1826 Like C<SvPVbyte>, but when C<sv> is undef, returns C<NULL>.
1827 
1828 =for apidoc Am|char*|SvPVbyte_or_null_nomg|SV* sv|STRLEN len
1829 Like C<SvPVbyte_or_null>, but does not process get magic.
1830 
1831 =for apidoc Am|char*|SvPVbyte_nolen|SV* sv
1832 Like C<SvPV_nolen>, but converts C<sv> to byte representation first if
1833 necessary.  If the SV cannot be downgraded from UTF-8, this croaks.
1834 
1835 =for apidoc Am|U32|SvIsCOW|SV* sv
1836 Returns a U32 value indicating whether the SV is Copy-On-Write (either shared
1837 hash key scalars, or full Copy On Write scalars if 5.9.0 is configured for
1838 COW).
1839 
1840 =for apidoc Am|bool|SvIsCOW_shared_hash|SV* sv
1841 Returns a boolean indicating whether the SV is Copy-On-Write shared hash key
1842 scalar.
1843 
1844 =cut
1845 */
1846 
1847 /* Let us hope that bitmaps for UV and IV are the same */
1848 #define SvIV(sv) (SvIOK_nog(sv) ? SvIVX(sv) : sv_2iv(sv))
1849 #define SvUV(sv) (SvUOK_nog(sv) ? SvUVX(sv) : sv_2uv(sv))
1850 #define SvNV(sv) (SvNOK_nog(sv) ? SvNVX(sv) : sv_2nv(sv))
1851 
1852 #define SvIV_nomg(sv) (SvIOK(sv) ? SvIVX(sv) : sv_2iv_flags(sv, 0))
1853 #define SvUV_nomg(sv) (SvUOK(sv) ? SvUVX(sv) : sv_2uv_flags(sv, 0))
1854 #define SvNV_nomg(sv) (SvNOK(sv) ? SvNVX(sv) : sv_2nv_flags(sv, 0))
1855 
1856 /* ----*/
1857 
1858 #define SvPV(sv, len)         SvPV_flags(sv, len, SV_GMAGIC)
1859 #define SvPV_const(sv, len)   SvPV_flags_const(sv, len, SV_GMAGIC)
1860 #define SvPV_mutable(sv, len) SvPV_flags_mutable(sv, len, SV_GMAGIC)
1861 
1862 #define SvPV_flags(sv, len, flags) \
1863     (SvPOK_nog(sv) \
1864      ? ((len = SvCUR(sv)), SvPVX(sv)) : sv_2pv_flags(sv, &len, flags))
1865 #define SvPV_flags_const(sv, len, flags) \
1866     (SvPOK_nog(sv) \
1867      ? ((len = SvCUR(sv)), SvPVX_const(sv)) : \
1868      (const char*) sv_2pv_flags(sv, &len, (flags|SV_CONST_RETURN)))
1869 #define SvPV_flags_const_nolen(sv, flags) \
1870     (SvPOK_nog(sv) \
1871      ? SvPVX_const(sv) : \
1872      (const char*) sv_2pv_flags(sv, 0, (flags|SV_CONST_RETURN)))
1873 #define SvPV_flags_mutable(sv, len, flags) \
1874     (SvPOK_nog(sv) \
1875      ? ((len = SvCUR(sv)), SvPVX_mutable(sv)) : \
1876      sv_2pv_flags(sv, &len, (flags|SV_MUTABLE_RETURN)))
1877 
1878 #define SvPV_force(sv, len) SvPV_force_flags(sv, len, SV_GMAGIC)
1879 #define SvPV_force_nolen(sv) SvPV_force_flags_nolen(sv, SV_GMAGIC)
1880 #define SvPV_force_mutable(sv, len) SvPV_force_flags_mutable(sv, len, SV_GMAGIC)
1881 
1882 #define SvPV_force_nomg(sv, len) SvPV_force_flags(sv, len, 0)
1883 #define SvPV_force_nomg_nolen(sv) SvPV_force_flags_nolen(sv, 0)
1884 
1885 #define SvPV_force_flags(sv, len, flags) \
1886     (SvPOK_pure_nogthink(sv) \
1887      ? ((len = SvCUR(sv)), SvPVX(sv)) : sv_pvn_force_flags(sv, &len, flags))
1888 
1889 #define SvPV_force_flags_nolen(sv, flags) \
1890     (SvPOK_pure_nogthink(sv) \
1891      ? SvPVX(sv) : sv_pvn_force_flags(sv, 0, flags))
1892 
1893 #define SvPV_force_flags_mutable(sv, len, flags) \
1894     (SvPOK_pure_nogthink(sv) \
1895      ? ((len = SvCUR(sv)), SvPVX_mutable(sv)) \
1896      : sv_pvn_force_flags(sv, &len, flags|SV_MUTABLE_RETURN))
1897 
1898 #define SvPV_nolen(sv) \
1899     (SvPOK_nog(sv) \
1900      ? SvPVX(sv) : sv_2pv_flags(sv, 0, SV_GMAGIC))
1901 
1902 /* "_nomg" in these defines means no mg_get() */
1903 #define SvPV_nomg_nolen(sv) \
1904     (SvPOK_nog(sv) \
1905      ? SvPVX(sv) : sv_2pv_flags(sv, 0, 0))
1906 
1907 #define SvPV_nolen_const(sv) \
1908     (SvPOK_nog(sv) \
1909      ? SvPVX_const(sv) : sv_2pv_flags(sv, 0, SV_GMAGIC|SV_CONST_RETURN))
1910 
1911 #define SvPV_nomg(sv, len) SvPV_flags(sv, len, 0)
1912 #define SvPV_nomg_const(sv, len) SvPV_flags_const(sv, len, 0)
1913 #define SvPV_nomg_const_nolen(sv) SvPV_flags_const_nolen(sv, 0)
1914 
1915 /* ----*/
1916 
1917 #define SvPVutf8(sv, len) \
1918     (SvPOK_utf8_nog(sv) \
1919      ? ((len = SvCUR(sv)), SvPVX(sv)) : sv_2pvutf8(sv, &len))
1920 
1921 #define SvPVutf8_or_null(sv, len) \
1922     (SvPOK_utf8_nog(sv) \
1923      ? ((len = SvCUR(sv)), SvPVX(sv)) : (SvGETMAGIC(sv), SvOK(sv)) \
1924      ? sv_2pvutf8_flags(sv, &len, 0) : ((len = 0), NULL))
1925 
1926 #define SvPVutf8_nomg(sv, len) \
1927     (SvPOK_utf8_nog(sv) \
1928      ? ((len = SvCUR(sv)), SvPVX(sv)) : sv_2pvutf8_flags(sv, &len, 0))
1929 
1930 #define SvPVutf8_or_null_nomg(sv, len) \
1931     (SvPOK_utf8_nog(sv) \
1932      ? ((len = SvCUR(sv)), SvPVX(sv)) : SvOK(sv) \
1933      ? sv_2pvutf8_flags(sv, &len, 0) : ((len = 0), NULL))
1934 
1935 #define SvPVutf8_force(sv, len) \
1936     (SvPOK_utf8_pure_nogthink(sv) \
1937      ? ((len = SvCUR(sv)), SvPVX(sv)) : sv_pvutf8n_force(sv, &len))
1938 
1939 #define SvPVutf8_nolen(sv) \
1940     (SvPOK_utf8_nog(sv) \
1941      ? SvPVX(sv) : sv_2pvutf8(sv, 0))
1942 
1943 /* ----*/
1944 
1945 #define SvPVbyte(sv, len) \
1946     (SvPOK_byte_nog(sv) \
1947      ? ((len = SvCUR(sv)), SvPVX(sv)) : sv_2pvbyte(sv, &len))
1948 
1949 #define SvPVbyte_or_null(sv, len) \
1950     (SvPOK_byte_nog(sv) \
1951      ? ((len = SvCUR(sv)), SvPVX(sv)) : (SvGETMAGIC(sv), SvOK(sv)) \
1952      ? sv_2pvbyte_flags(sv, &len, 0) : ((len = 0), NULL))
1953 
1954 #define SvPVbyte_nomg(sv, len) \
1955     (SvPOK_byte_nog(sv) \
1956      ? ((len = SvCUR(sv)), SvPVX(sv)) : sv_2pvbyte_flags(sv, &len, 0))
1957 
1958 #define SvPVbyte_or_null_nomg(sv, len) \
1959     (SvPOK_utf8_nog(sv) \
1960      ? ((len = SvCUR(sv)), SvPVX(sv)) : SvOK(sv) \
1961      ? sv_2pvbyte_flags(sv, &len, 0) : ((len = 0), NULL))
1962 
1963 #define SvPVbyte_force(sv, len) \
1964     (SvPOK_byte_pure_nogthink(sv) \
1965      ? ((len = SvCUR(sv)), SvPVX(sv)) : sv_pvbyten_force(sv, &len))
1966 
1967 #define SvPVbyte_nolen(sv) \
1968     (SvPOK_byte_nog(sv) \
1969      ? SvPVX(sv) : sv_2pvbyte(sv, 0))
1970 
1971 
1972 /* define FOOx(): idempotent versions of FOO(). If possible, use a local
1973  * var to evaluate the arg once; failing that, use a global if possible;
1974  * failing that, call a function to do the work
1975  */
1976 
1977 #define SvPVx_force(sv, len) sv_pvn_force(sv, &len)
1978 #define SvPVutf8x_force(sv, len) sv_pvutf8n_force(sv, &len)
1979 #define SvPVbytex_force(sv, len) sv_pvbyten_force(sv, &len)
1980 
1981 #define SvTRUEx(sv)        SvTRUE(sv)
1982 #define SvTRUEx_nomg(sv)   SvTRUE_nomg(sv)
1983 #define SvTRUE_nomg_NN(sv) SvTRUE_common(sv, TRUE)
1984 
1985 #if defined(PERL_USE_GCC_BRACE_GROUPS)
1986 
1987 #  define SvIVx(sv) ({SV *_sv = MUTABLE_SV(sv); SvIV(_sv); })
1988 #  define SvUVx(sv) ({SV *_sv = MUTABLE_SV(sv); SvUV(_sv); })
1989 #  define SvNVx(sv) ({SV *_sv = MUTABLE_SV(sv); SvNV(_sv); })
1990 #  define SvPVx(sv, len) ({SV *_sv = (sv); SvPV(_sv, len); })
1991 #  define SvPVx_const(sv, len) ({SV *_sv = (sv); SvPV_const(_sv, len); })
1992 #  define SvPVx_nolen(sv) ({SV *_sv = (sv); SvPV_nolen(_sv); })
1993 #  define SvPVx_nolen_const(sv) ({SV *_sv = (sv); SvPV_nolen_const(_sv); })
1994 #  define SvPVutf8x(sv, len) ({SV *_sv = (sv); SvPVutf8(_sv, len); })
1995 #  define SvPVbytex(sv, len) ({SV *_sv = (sv); SvPVbyte(_sv, len); })
1996 #  define SvPVbytex_nolen(sv) ({SV *_sv = (sv); SvPVbyte_nolen(_sv); })
1997 
1998 #else /* __GNUC__ */
1999 
2000 /* These inlined macros use globals, which will require a thread
2001  * declaration in user code, so we avoid them under threads */
2002 
2003 #  define SvIVx(sv) ((PL_Sv = (sv)), SvIV(PL_Sv))
2004 #  define SvUVx(sv) ((PL_Sv = (sv)), SvUV(PL_Sv))
2005 #  define SvNVx(sv) ((PL_Sv = (sv)), SvNV(PL_Sv))
2006 #  define SvPVx(sv, len) ((PL_Sv = (sv)), SvPV(PL_Sv, len))
2007 #  define SvPVx_const(sv, len) ((PL_Sv = (sv)), SvPV_const(PL_Sv, len))
2008 #  define SvPVx_nolen(sv) ((PL_Sv = (sv)), SvPV_nolen(PL_Sv))
2009 #  define SvPVx_nolen_const(sv) ((PL_Sv = (sv)), SvPV_nolen_const(PL_Sv))
2010 #  define SvPVutf8x(sv, len) ((PL_Sv = (sv)), SvPVutf8(PL_Sv, len))
2011 #  define SvPVbytex(sv, len) ((PL_Sv = (sv)), SvPVbyte(PL_Sv, len))
2012 #  define SvPVbytex_nolen(sv) ((PL_Sv = (sv)), SvPVbyte_nolen(PL_Sv))
2013 #endif /* __GNU__ */
2014 
2015 #define SvPVXtrue(sv)	(					\
2016     ((XPV*)SvANY((sv))) 					\
2017      && (							\
2018         ((XPV*)SvANY((sv)))->xpv_cur > 1			\
2019         || (							\
2020             ((XPV*)SvANY((sv)))->xpv_cur			\
2021             && *(sv)->sv_u.svu_pv != '0'				\
2022         )							\
2023     )								\
2024 )
2025 
2026 #define SvIsCOW(sv)              (SvFLAGS(sv) & SVf_IsCOW)
2027 #define SvIsCOW_on(sv)           (SvFLAGS(sv) |= SVf_IsCOW)
2028 #define SvIsCOW_off(sv)          (SvFLAGS(sv) &= ~(SVf_IsCOW|SVppv_STATIC))
2029 #define SvIsCOW_shared_hash(sv)  ((SvFLAGS(sv) & (SVf_IsCOW|SVppv_STATIC)) == (SVf_IsCOW) && SvLEN(sv) == 0)
2030 #define SvIsCOW_static(sv)       ((SvFLAGS(sv) & (SVf_IsCOW|SVppv_STATIC)) == (SVf_IsCOW|SVppv_STATIC))
2031 
2032 #define SvSHARED_HEK_FROM_PV(pvx) \
2033         ((struct hek*)(pvx - STRUCT_OFFSET(struct hek, hek_key)))
2034 /*
2035 =for apidoc Am|struct hek*|SvSHARED_HASH|SV * sv
2036 Returns the hash for C<sv> created by C<L</newSVpvn_share>>.
2037 
2038 =cut
2039 */
2040 #define SvSHARED_HASH(sv) (0 + SvSHARED_HEK_FROM_PV(SvPVX_const(sv))->hek_hash)
2041 
2042 /* flag values for sv_*_flags functions */
2043 #define SV_UTF8_NO_ENCODING	0       /* No longer used */
2044 
2045 /*
2046 =for apidoc AmnhD||SV_UTF8_NO_ENCODING
2047 
2048 =cut
2049 */
2050 
2051 #define SV_IMMEDIATE_UNREF	1
2052 #define SV_GMAGIC		2
2053 #define SV_COW_DROP_PV		4
2054 #define SV_NOSTEAL		16
2055 #define SV_CONST_RETURN		32
2056 #define SV_MUTABLE_RETURN	64
2057 #define SV_SMAGIC		128
2058 #define SV_HAS_TRAILING_NUL	256
2059 #define SV_COW_SHARED_HASH_KEYS	512
2060 /* This one is only enabled for PERL_OLD_COPY_ON_WRITE */
2061 /* XXX This flag actually enabled for any COW.  But it appears not to do
2062        anything.  Can we just remove it?  Or will it serve some future
2063        purpose.  */
2064 #define SV_COW_OTHER_PVS	1024
2065 /* Make sv_2pv_flags return NULL if something is undefined.  */
2066 #define SV_UNDEF_RETURNS_NULL	2048
2067 /* Tell sv_utf8_upgrade() to not check to see if an upgrade is really needed.
2068  * This is used when the caller has already determined it is, and avoids
2069  * redundant work */
2070 #define SV_FORCE_UTF8_UPGRADE	4096
2071 /* if (after resolving magic etc), the SV is found to be overloaded,
2072  * don't call the overload magic, just return as-is */
2073 #define SV_SKIP_OVERLOAD	8192
2074 #define SV_CATBYTES		16384
2075 #define SV_CATUTF8		32768
2076 
2077 /* The core is safe for this COW optimisation. XS code on CPAN may not be.
2078    So only default to doing the COW setup if we're in the core.
2079  */
2080 #ifdef PERL_CORE
2081 #  ifndef SV_DO_COW_SVSETSV
2082 #    define SV_DO_COW_SVSETSV	SV_COW_SHARED_HASH_KEYS|SV_COW_OTHER_PVS
2083 #  endif
2084 #endif
2085 
2086 #ifndef SV_DO_COW_SVSETSV
2087 #  define SV_DO_COW_SVSETSV	0
2088 #endif
2089 
2090 
2091 #define sv_unref(sv)    	sv_unref_flags(sv, 0)
2092 #define sv_force_normal(sv)	sv_force_normal_flags(sv, 0)
2093 #define sv_usepvn(sv, p, l)	sv_usepvn_flags(sv, p, l, 0)
2094 #define sv_usepvn_mg(sv, p, l)	sv_usepvn_flags(sv, p, l, SV_SMAGIC)
2095 
2096 /* We are about to replace the SV's current value. So if it's copy on write
2097    we need to normalise it. Use the SV_COW_DROP_PV flag hint to say that
2098    the value is about to get thrown away, so drop the PV rather than go to
2099    the effort of making a read-write copy only for it to get immediately
2100    discarded.  */
2101 
2102 #define SV_CHECK_THINKFIRST_COW_DROP(sv) if (SvTHINKFIRST(sv)) \
2103                                     sv_force_normal_flags(sv, SV_COW_DROP_PV)
2104 
2105 #ifdef PERL_COPY_ON_WRITE
2106 #   define SvCANCOW(sv)					    \
2107         (SvIsCOW(sv)					     \
2108          ? SvLEN(sv) ? CowREFCNT(sv) != SV_COW_REFCNT_MAX : 1 \
2109          : (SvFLAGS(sv) & CAN_COW_MASK) == CAN_COW_FLAGS       \
2110                             && SvCUR(sv)+1 < SvLEN(sv))
2111    /* Note: To allow 256 COW "copies", a refcnt of 0 means 1. */
2112 #   define CowREFCNT(sv)	(*(U8 *)(SvPVX(sv)+SvLEN(sv)-1))
2113 #   define SV_COW_REFCNT_MAX	nBIT_UMAX(sizeof(U8) * CHARBITS)
2114 #   define CAN_COW_MASK	(SVf_POK|SVf_ROK|SVp_POK|SVf_FAKE| \
2115                          SVf_OOK|SVf_BREAK|SVf_READONLY|SVf_PROTECT)
2116 #endif
2117 
2118 #define CAN_COW_FLAGS	(SVp_POK|SVf_POK)
2119 
2120 #define SV_CHECK_THINKFIRST(sv) if (SvTHINKFIRST(sv)) \
2121                                     sv_force_normal_flags(sv, 0)
2122 
2123 
2124 /* all these 'functions' are now just macros */
2125 
2126 #define sv_pv(sv) SvPV_nolen(sv)
2127 #define sv_pvutf8(sv) SvPVutf8_nolen(sv)
2128 #define sv_pvbyte(sv) SvPVbyte_nolen(sv)
2129 
2130 #define sv_pvn_force_nomg(sv, lp) sv_pvn_force_flags(sv, lp, 0)
2131 #define sv_utf8_upgrade_flags(sv, flags) sv_utf8_upgrade_flags_grow(sv, flags, 0)
2132 #define sv_utf8_upgrade_nomg(sv) sv_utf8_upgrade_flags(sv, 0)
2133 #define sv_utf8_downgrade(sv, fail_ok) sv_utf8_downgrade_flags(sv, fail_ok, SV_GMAGIC)
2134 #define sv_utf8_downgrade_nomg(sv, fail_ok) sv_utf8_downgrade_flags(sv, fail_ok, 0)
2135 #define sv_catpvn_nomg(dsv, sstr, slen) sv_catpvn_flags(dsv, sstr, slen, 0)
2136 #define sv_catpv_nomg(dsv, sstr) sv_catpv_flags(dsv, sstr, 0)
2137 #define sv_setsv(dsv, ssv) \
2138         sv_setsv_flags(dsv, ssv, SV_GMAGIC|SV_DO_COW_SVSETSV)
2139 #define sv_setsv_nomg(dsv, ssv) sv_setsv_flags(dsv, ssv, SV_DO_COW_SVSETSV)
2140 #define sv_catsv(dsv, ssv) sv_catsv_flags(dsv, ssv, SV_GMAGIC)
2141 #define sv_catsv_nomg(dsv, ssv) sv_catsv_flags(dsv, ssv, 0)
2142 #define sv_catsv_mg(dsv, ssv) sv_catsv_flags(dsv, ssv, SV_GMAGIC|SV_SMAGIC)
2143 #define sv_catpvn(dsv, sstr, slen) sv_catpvn_flags(dsv, sstr, slen, SV_GMAGIC)
2144 #define sv_catpvn_mg(dsv, sstr, slen) sv_catpvn_flags(dsv, sstr, slen, SV_GMAGIC|SV_SMAGIC);
2145 #define sv_copypv(dsv, ssv) sv_copypv_flags(dsv, ssv, SV_GMAGIC)
2146 #define sv_copypv_nomg(dsv, ssv) sv_copypv_flags(dsv, ssv, 0)
2147 #define sv_2pv(sv, lp) sv_2pv_flags(sv, lp, SV_GMAGIC)
2148 #define sv_2pv_nolen(sv) sv_2pv(sv, 0)
2149 #define sv_2pvbyte(sv, lp) sv_2pvbyte_flags(sv, lp, SV_GMAGIC)
2150 #define sv_2pvbyte_nolen(sv) sv_2pvbyte(sv, 0)
2151 #define sv_2pvutf8(sv, lp) sv_2pvutf8_flags(sv, lp, SV_GMAGIC)
2152 #define sv_2pvutf8_nolen(sv) sv_2pvutf8(sv, 0)
2153 #define sv_2pv_nomg(sv, lp) sv_2pv_flags(sv, lp, 0)
2154 #define sv_pvn_force(sv, lp) sv_pvn_force_flags(sv, lp, SV_GMAGIC)
2155 #define sv_utf8_upgrade(sv) sv_utf8_upgrade_flags(sv, SV_GMAGIC)
2156 #define sv_2iv(sv) sv_2iv_flags(sv, SV_GMAGIC)
2157 #define sv_2uv(sv) sv_2uv_flags(sv, SV_GMAGIC)
2158 #define sv_2nv(sv) sv_2nv_flags(sv, SV_GMAGIC)
2159 #define sv_eq(sv1, sv2) sv_eq_flags(sv1, sv2, SV_GMAGIC)
2160 #define sv_cmp(sv1, sv2) sv_cmp_flags(sv1, sv2, SV_GMAGIC)
2161 #define sv_cmp_locale(sv1, sv2) sv_cmp_locale_flags(sv1, sv2, SV_GMAGIC)
2162 #define sv_collxfrm(sv, nxp) sv_collxfrm_flags(sv, nxp, SV_GMAGIC)
2163 #define sv_2bool(sv) sv_2bool_flags(sv, SV_GMAGIC)
2164 #define sv_2bool_nomg(sv) sv_2bool_flags(sv, 0)
2165 #define sv_insert(bigstr, offset, len, little, littlelen)		\
2166         Perl_sv_insert_flags(aTHX_ (bigstr),(offset), (len), (little),	\
2167                              (littlelen), SV_GMAGIC)
2168 #define sv_mortalcopy(sv) \
2169         Perl_sv_mortalcopy_flags(aTHX_ sv, SV_GMAGIC|SV_DO_COW_SVSETSV)
2170 #define sv_cathek(sv,hek)					    \
2171         STMT_START {						     \
2172             HEK * const bmxk = hek;				      \
2173             sv_catpvn_flags(sv, HEK_KEY(bmxk), HEK_LEN(bmxk),	       \
2174                             HEK_UTF8(bmxk) ? SV_CATUTF8 : SV_CATBYTES); \
2175         } STMT_END
2176 
2177 /* Should be named SvCatPVN_utf8_upgrade? */
2178 #define sv_catpvn_nomg_utf8_upgrade(dsv, sstr, slen, nsv)	\
2179         STMT_START {					\
2180             if (!(nsv))					\
2181                 nsv = newSVpvn_flags(sstr, slen, SVs_TEMP);	\
2182             else					\
2183                 sv_setpvn(nsv, sstr, slen);		\
2184             SvUTF8_off(nsv);				\
2185             sv_utf8_upgrade(nsv);			\
2186             sv_catsv_nomg(dsv, nsv);			\
2187         } STMT_END
2188 #define sv_catpvn_nomg_maybeutf8(dsv, sstr, slen, is_utf8) \
2189         sv_catpvn_flags(dsv, sstr, slen, (is_utf8)?SV_CATUTF8:SV_CATBYTES)
2190 
2191 #if defined(PERL_CORE) || defined(PERL_EXT)
2192 # define sv_or_pv_len_utf8(sv, pv, bytelen)	      \
2193     (SvGAMAGIC(sv)				       \
2194         ? utf8_length((U8 *)(pv), (U8 *)(pv)+(bytelen))	\
2195         : sv_len_utf8(sv))
2196 #endif
2197 
2198 /*
2199 =for apidoc newRV
2200 =for apidoc_item ||newRV_inc|
2201 
2202 These are identical.  They create an RV wrapper for an SV.  The reference count
2203 for the original SV is incremented.
2204 
2205 =cut
2206 */
2207 
2208 #define newRV_inc(sv)	newRV(sv)
2209 
2210 /* the following macros update any magic values this C<sv> is associated with */
2211 
2212 /*
2213 =for apidoc_section $SV
2214 
2215 =for apidoc Am|void|SvGETMAGIC|SV* sv
2216 Invokes C<L</mg_get>> on an SV if it has 'get' magic.  For example, this
2217 will call C<FETCH> on a tied variable.  This macro evaluates its
2218 argument more than once.
2219 
2220 =for apidoc Am|void|SvSETMAGIC|SV* sv
2221 Invokes C<L</mg_set>> on an SV if it has 'set' magic.  This is necessary
2222 after modifying a scalar, in case it is a magical variable like C<$|>
2223 or a tied variable (it calls C<STORE>).  This macro evaluates its
2224 argument more than once.
2225 
2226 =for apidoc Am|void|SvSetSV|SV* dsv|SV* ssv
2227 =for apidoc_item SvSetMagicSV
2228 =for apidoc_item SvSetSV_nosteal
2229 =for apidoc_item SvSetMagicSV_nosteal
2230 
2231 if C<dsv> is the same as C<ssv>, these do nothing.  Otherwise they all call
2232 some form of C<L</sv_setsv>>.  They may evaluate their arguments more than
2233 once.
2234 
2235 The only differences are:
2236 
2237 C<SvSetMagicSV> and C<SvSetMagicSV_nosteal> perform any required 'set' magic
2238 afterwards on the destination SV; C<SvSetSV> and C<SvSetSV_nosteal> do not.
2239 
2240 C<SvSetSV_nosteal> C<SvSetMagicSV_nosteal> call a non-destructive version of
2241 C<sv_setsv>.
2242 
2243 =for apidoc Am|void|SvSHARE|SV* sv
2244 Arranges for C<sv> to be shared between threads if a suitable module
2245 has been loaded.
2246 
2247 =for apidoc Am|void|SvLOCK|SV* sv
2248 Arranges for a mutual exclusion lock to be obtained on C<sv> if a suitable module
2249 has been loaded.
2250 
2251 =for apidoc Am|void|SvUNLOCK|SV* sv
2252 Releases a mutual exclusion lock on C<sv> if a suitable module
2253 has been loaded.
2254 
2255 =for apidoc_section $SV
2256 
2257 =for apidoc Am|char *|SvGROW|SV* sv|STRLEN len
2258 Expands the character buffer in the SV so that it has room for the
2259 indicated number of bytes (remember to reserve space for an extra trailing
2260 C<NUL> character).  Calls C<sv_grow> to perform the expansion if necessary.
2261 Returns a pointer to the character
2262 buffer.  SV must be of type >= C<SVt_PV>.  One
2263 alternative is to call C<sv_grow> if you are not sure of the type of SV.
2264 
2265 You might mistakenly think that C<len> is the number of bytes to add to the
2266 existing size, but instead it is the total size C<sv> should be.
2267 
2268 =for apidoc Am|char *|SvPVCLEAR|SV* sv
2269 Ensures that sv is a SVt_PV and that its SvCUR is 0, and that it is
2270 properly null terminated. Equivalent to sv_setpvs(""), but more efficient.
2271 
2272 =cut
2273 */
2274 
2275 #define SvPVCLEAR(sv) sv_setpv_bufsize(sv,0,0)
2276 #define SvSHARE(sv) PL_sharehook(aTHX_ sv)
2277 #define SvLOCK(sv) PL_lockhook(aTHX_ sv)
2278 #define SvUNLOCK(sv) PL_unlockhook(aTHX_ sv)
2279 #define SvDESTROYABLE(sv) PL_destroyhook(aTHX_ sv)
2280 
2281 #define SvGETMAGIC(x) ((void)(UNLIKELY(SvGMAGICAL(x)) && mg_get(x)))
2282 #define SvSETMAGIC(x) STMT_START { if (UNLIKELY(SvSMAGICAL(x))) mg_set(x); } STMT_END
2283 
2284 #define SvSetSV_and(dst,src,finally) \
2285         STMT_START {					\
2286             if (LIKELY((dst) != (src))) {		\
2287                 sv_setsv(dst, src);			\
2288                 finally;				\
2289             }						\
2290         } STMT_END
2291 #define SvSetSV_nosteal_and(dst,src,finally) \
2292         STMT_START {					\
2293             if (LIKELY((dst) != (src))) {			\
2294                 sv_setsv_flags(dst, src, SV_GMAGIC | SV_NOSTEAL | SV_DO_COW_SVSETSV);	\
2295                 finally;				\
2296             }						\
2297         } STMT_END
2298 
2299 #define SvSetSV(dst,src) \
2300                 SvSetSV_and(dst,src,/*nothing*/;)
2301 #define SvSetSV_nosteal(dst,src) \
2302                 SvSetSV_nosteal_and(dst,src,/*nothing*/;)
2303 
2304 #define SvSetMagicSV(dst,src) \
2305                 SvSetSV_and(dst,src,SvSETMAGIC(dst))
2306 #define SvSetMagicSV_nosteal(dst,src) \
2307                 SvSetSV_nosteal_and(dst,src,SvSETMAGIC(dst))
2308 
2309 
2310 #if !defined(SKIP_DEBUGGING)
2311 #define SvPEEK(sv) sv_peek(sv)
2312 #else
2313 #define SvPEEK(sv) ""
2314 #endif
2315 
2316 /* Is this a per-interpreter immortal SV (rather than global)?
2317  * These should either occupy adjacent entries in the interpreter struct
2318  * (MULTIPLICITY) or adjacent elements of PL_sv_immortals[] otherwise.
2319  * The unsigned (Size_t) cast avoids the need for a second < 0 condition.
2320  */
2321 #define SvIMMORTAL_INTERP(sv) ((Size_t)((sv) - &PL_sv_yes) < 4)
2322 
2323 /* Does this immortal have a true value? Currently only PL_sv_yes does. */
2324 #define SvIMMORTAL_TRUE(sv)   ((sv) == &PL_sv_yes)
2325 
2326 /* the SvREADONLY() test is to quickly reject most SVs */
2327 #define SvIMMORTAL(sv) \
2328                 (  SvREADONLY(sv) \
2329                 && (SvIMMORTAL_INTERP(sv) || (sv) == &PL_sv_placeholder))
2330 
2331 #ifdef DEBUGGING
2332    /* exercise the immortal resurrection code in sv_free2() */
2333 #  define SvREFCNT_IMMORTAL 1000
2334 #else
2335 #  define SvREFCNT_IMMORTAL ((~(U32)0)/2)
2336 #endif
2337 
2338 /*
2339 =for apidoc Am|SV *|boolSV|bool b
2340 
2341 Returns a true SV if C<b> is a true value, or a false SV if C<b> is 0.
2342 
2343 See also C<L</PL_sv_yes>> and C<L</PL_sv_no>>.
2344 
2345 =cut
2346 */
2347 
2348 #define boolSV(b) ((b) ? &PL_sv_yes : &PL_sv_no)
2349 
2350 /*
2351 =for apidoc Am|void|sv_setbool|SV *sv|bool b
2352 =for apidoc_item |void|sv_setbool_mg|SV *sv|bool b
2353 
2354 These set an SV to a true or false boolean value, upgrading first if necessary.
2355 
2356 They differ only in that C<sv_setbool_mg> handles 'set' magic; C<sv_setbool>
2357 does not.
2358 
2359 =cut
2360 */
2361 
2362 #define sv_setbool(sv, b)     sv_setsv(sv, boolSV(b))
2363 #define sv_setbool_mg(sv, b)  sv_setsv_mg(sv, boolSV(b))
2364 
2365 #define isGV(sv) (SvTYPE(sv) == SVt_PVGV)
2366 /* If I give every macro argument a different name, then there won't be bugs
2367    where nested macros get confused. Been there, done that.  */
2368 /*
2369 =for apidoc Am|bool|isGV_with_GP|SV * sv
2370 Returns a boolean as to whether or not C<sv> is a GV with a pointer to a GP
2371 (glob pointer).
2372 
2373 =cut
2374 */
2375 #define isGV_with_GP(pwadak) \
2376         (((SvFLAGS(pwadak) & (SVp_POK|SVpgv_GP)) == SVpgv_GP)	\
2377         && (SvTYPE(pwadak) == SVt_PVGV || SvTYPE(pwadak) == SVt_PVLV))
2378 #define isGV_with_GP_on(sv)	STMT_START {			       \
2379         assert (SvTYPE(sv) == SVt_PVGV || SvTYPE(sv) == SVt_PVLV); \
2380         assert (!SvPOKp(sv));					       \
2381         assert (!SvIOKp(sv));					       \
2382         (SvFLAGS(sv) |= SVpgv_GP);				       \
2383     } STMT_END
2384 #define isGV_with_GP_off(sv)	STMT_START {			       \
2385         assert (SvTYPE(sv) == SVt_PVGV || SvTYPE(sv) == SVt_PVLV); \
2386         assert (!SvPOKp(sv));					       \
2387         assert (!SvIOKp(sv));					       \
2388         (SvFLAGS(sv) &= ~SVpgv_GP);				       \
2389     } STMT_END
2390 #ifdef PERL_CORE
2391 # define isGV_or_RVCV(kadawp) \
2392     (isGV(kadawp) || (SvROK(kadawp) && SvTYPE(SvRV(kadawp)) == SVt_PVCV))
2393 #endif
2394 #define isREGEXP(sv) \
2395     (SvTYPE(sv) == SVt_REGEXP				      \
2396      || (SvFLAGS(sv) & (SVTYPEMASK|SVpgv_GP|SVf_FAKE))        \
2397          == (SVt_PVLV|SVf_FAKE))
2398 
2399 
2400 #ifdef PERL_ANY_COW
2401 # define SvGROW(sv,len) \
2402         (SvIsCOW(sv) || SvLEN(sv) < (len) ? sv_grow(sv,len) : SvPVX(sv))
2403 #else
2404 # define SvGROW(sv,len) (SvLEN(sv) < (len) ? sv_grow(sv,len) : SvPVX(sv))
2405 #endif
2406 #define SvGROW_mutable(sv,len) \
2407     (SvLEN(sv) < (len) ? sv_grow(sv,len) : SvPVX_mutable(sv))
2408 #define Sv_Grow sv_grow
2409 
2410 #define CLONEf_COPY_STACKS 1
2411 #define CLONEf_KEEP_PTR_TABLE 2
2412 #define CLONEf_CLONE_HOST 4
2413 #define CLONEf_JOIN_IN 8
2414 
2415 struct clone_params {
2416   AV* stashes;
2417   UV  flags;
2418   PerlInterpreter *proto_perl;
2419   PerlInterpreter *new_perl;
2420   AV *unreferenced;
2421 };
2422 
2423 /* SV_NOSTEAL prevents TEMP buffers being, well, stolen, and saves games
2424    with SvTEMP_off and SvTEMP_on round a call to sv_setsv.  */
2425 #define newSVsv(sv) newSVsv_flags((sv), SV_GMAGIC|SV_NOSTEAL)
2426 #define newSVsv_nomg(sv) newSVsv_flags((sv), SV_NOSTEAL)
2427 
2428 /*
2429 =for apidoc Am|SV*|newSVpvn_utf8|const char* s|STRLEN len|U32 utf8
2430 
2431 Creates a new SV and copies a string (which may contain C<NUL> (C<\0>)
2432 characters) into it.  If C<utf8> is true, calls
2433 C<SvUTF8_on> on the new SV.  Implemented as a wrapper around C<newSVpvn_flags>.
2434 
2435 =cut
2436 */
2437 
2438 #define newSVpvn_utf8(s, len, u) newSVpvn_flags((s), (len), (u) ? SVf_UTF8 : 0)
2439 
2440 /*
2441 =for apidoc Amx|SV*|newSVpadname|PADNAME *pn
2442 
2443 Creates a new SV containing the pad name.
2444 
2445 =cut
2446 */
2447 
2448 #define newSVpadname(pn) newSVpvn_utf8(PadnamePV(pn), PadnameLEN(pn), TRUE)
2449 
2450 /*
2451 =for apidoc Am|void|SvOOK_offset|SV*sv|STRLEN len
2452 
2453 Reads into C<len> the offset from C<SvPVX> back to the true start of the
2454 allocated buffer, which will be non-zero if C<sv_chop> has been used to
2455 efficiently remove characters from start of the buffer.  Implemented as a
2456 macro, which takes the address of C<len>, which must be of type C<STRLEN>.
2457 Evaluates C<sv> more than once.  Sets C<len> to 0 if C<SvOOK(sv)> is false.
2458 
2459 =cut
2460 */
2461 
2462 #ifdef DEBUGGING
2463 /* Does the bot know something I don't?
2464 10:28 <@Nicholas> metabatman
2465 10:28 <+meta> Nicholas: crash
2466 */
2467 #  define SvOOK_offset(sv, offset) STMT_START {				\
2468         STATIC_ASSERT_STMT(sizeof(offset) == sizeof(STRLEN));		\
2469         if (SvOOK(sv)) {						\
2470             const U8 *_crash = (U8*)SvPVX_const(sv);			\
2471             (offset) = *--_crash;					\
2472             if (!(offset)) {						\
2473                 _crash -= sizeof(STRLEN);				\
2474                 Copy(_crash, (U8 *)&(offset), sizeof(STRLEN), U8);	\
2475             }								\
2476             {								\
2477                 /* Validate the preceding buffer's sentinels to		\
2478                    verify that no-one is using it.  */			\
2479                 const U8 *const _bonk = (U8*)SvPVX_const(sv) - (offset);\
2480                 while (_crash > _bonk) {				\
2481                     --_crash;						\
2482                     assert (*_crash == (U8)PTR2UV(_crash));		\
2483                 }							\
2484             }								\
2485         } else {							\
2486             (offset) = 0;						\
2487         }								\
2488     } STMT_END
2489 #else
2490     /* This is the same code, but avoids using any temporary variables:  */
2491 #  define SvOOK_offset(sv, offset) STMT_START {				\
2492         STATIC_ASSERT_STMT(sizeof(offset) == sizeof(STRLEN));		\
2493         if (SvOOK(sv)) {						\
2494             (offset) = ((U8*)SvPVX_const(sv))[-1];			\
2495             if (!(offset)) {						\
2496                 Copy(SvPVX_const(sv) - 1 - sizeof(STRLEN),		\
2497                      (U8*)&(offset), sizeof(STRLEN), U8);		\
2498             }								\
2499         } else {							\
2500             (offset) = 0;						\
2501         }								\
2502     } STMT_END
2503 #endif
2504 
2505 #define newIO()	MUTABLE_IO(newSV_type(SVt_PVIO))
2506 
2507 #if defined(PERL_CORE) || defined(PERL_EXT)
2508 
2509 #  define SV_CONST(name) \
2510         PL_sv_consts[SV_CONST_##name] \
2511                 ? PL_sv_consts[SV_CONST_##name] \
2512                 : (PL_sv_consts[SV_CONST_##name] = newSVpv_share(#name, 0))
2513 
2514 #  define SV_CONST_TIESCALAR 0
2515 #  define SV_CONST_TIEARRAY 1
2516 #  define SV_CONST_TIEHASH 2
2517 #  define SV_CONST_TIEHANDLE 3
2518 
2519 #  define SV_CONST_FETCH 4
2520 #  define SV_CONST_FETCHSIZE 5
2521 #  define SV_CONST_STORE 6
2522 #  define SV_CONST_STORESIZE 7
2523 #  define SV_CONST_EXISTS 8
2524 
2525 #  define SV_CONST_PUSH 9
2526 #  define SV_CONST_POP 10
2527 #  define SV_CONST_SHIFT 11
2528 #  define SV_CONST_UNSHIFT 12
2529 #  define SV_CONST_SPLICE 13
2530 #  define SV_CONST_EXTEND 14
2531 
2532 #  define SV_CONST_FIRSTKEY 15
2533 #  define SV_CONST_NEXTKEY 16
2534 #  define SV_CONST_SCALAR 17
2535 
2536 #  define SV_CONST_OPEN 18
2537 #  define SV_CONST_WRITE 19
2538 #  define SV_CONST_PRINT 20
2539 #  define SV_CONST_PRINTF 21
2540 #  define SV_CONST_READ 22
2541 #  define SV_CONST_READLINE 23
2542 #  define SV_CONST_GETC 24
2543 #  define SV_CONST_SEEK 25
2544 #  define SV_CONST_TELL 26
2545 #  define SV_CONST_EOF 27
2546 #  define SV_CONST_BINMODE 28
2547 #  define SV_CONST_FILENO 29
2548 #  define SV_CONST_CLOSE 30
2549 
2550 #  define SV_CONST_DELETE 31
2551 #  define SV_CONST_CLEAR 32
2552 #  define SV_CONST_UNTIE 33
2553 #  define SV_CONST_DESTROY 34
2554 #endif
2555 
2556 #define SV_CONSTS_COUNT 35
2557 
2558 /*
2559  * Bodyless IVs and NVs!
2560  *
2561  * Since 5.9.2, we can avoid allocating a body for SVt_IV-type SVs.
2562  * Since the larger IV-holding variants of SVs store their integer
2563  * values in their respective bodies, the family of SvIV() accessor
2564  * macros would  naively have to branch on the SV type to find the
2565  * integer value either in the HEAD or BODY. In order to avoid this
2566  * expensive branch, a clever soul has deployed a great hack:
2567  * We set up the SvANY pointer such that instead of pointing to a
2568  * real body, it points into the memory before the location of the
2569  * head. We compute this pointer such that the location of
2570  * the integer member of the hypothetical body struct happens to
2571  * be the same as the location of the integer member of the bodyless
2572  * SV head. This now means that the SvIV() family of accessors can
2573  * always read from the (hypothetical or real) body via SvANY.
2574  *
2575  * Since the 5.21 dev series, we employ the same trick for NVs
2576  * if the architecture can support it (NVSIZE <= IVSIZE).
2577  */
2578 
2579 /* The following two macros compute the necessary offsets for the above
2580  * trick and store them in SvANY for SvIV() (and friends) to use. */
2581 
2582 #ifdef PERL_CORE
2583 #  define SET_SVANY_FOR_BODYLESS_IV(sv) \
2584         SvANY(sv) =   (XPVIV*)((char*)&(sv->sv_u.svu_iv) \
2585                     - STRUCT_OFFSET(XPVIV, xiv_iv))
2586 
2587 #  define SET_SVANY_FOR_BODYLESS_NV(sv) \
2588         SvANY(sv) =   (XPVNV*)((char*)&(sv->sv_u.svu_nv) \
2589                     - STRUCT_OFFSET(XPVNV, xnv_u.xnv_nv))
2590 #endif
2591 
2592 /*
2593  * ex: set ts=8 sts=4 sw=4 et:
2594  */
2595