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perl @ 27483 fix lib/Pod/Simple/t/corpustest.t to work on VMS ODS-2
[perl5.git] / cv.h
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a0d0e21e 1/* cv.h
79072805 2 *
4bb101f2 3 * Copyright (C) 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1999,
bf53b3a5 4 * 2000, 2001, 2002, 2003, 2004, 2005, 2006, by Larry Wall and others
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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 *
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9 */
10
7c60e434 11/* This structure must the beginning of XPVFM in sv.h */
44a8e56a 12
79072805 13struct xpvcv {
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14 union {
15 NV xnv_nv; /* numeric value, if any */
16 HV * xgv_stash;
17 } xnv_u;
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18 STRLEN xpv_cur; /* length of xp_pv as a C string */
19 STRLEN xpv_len; /* allocated size */
e4305a63 20 union {
bb172083 21 IV xivu_iv;
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22 UV xivu_uv;
23 void * xivu_p1;
bb172083 24 I32 xivu_i32; /* depth, >= 2 indicates recursive call */
69ecfd12 25 HEK * xivu_namehek;
311a25d9 26 } xiv_u;
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27 union {
28 MAGIC* xmg_magic; /* linked list of magicalness */
29 HV* xmg_ourstash; /* Stash for our (when SvPAD_OUR is true) */
30 } xmg_u;
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31 HV* xmg_stash; /* class package */
32
33 HV * xcv_stash;
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34 union {
35 OP * xcv_start;
36 ANY xcv_xsubany;
37 } xcv_start_u;
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38 union {
39 OP * xcv_root;
40 void (*xcv_xsub) (pTHX_ CV*);
41 } xcv_root_u;
8990e307 42 GV * xcv_gv;
57843af0 43 char * xcv_file;
dd2155a4 44 PADLIST * xcv_padlist;
748a9306 45 CV * xcv_outside;
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46 U32 xcv_outside_seq; /* the COP sequence (at the point of our
47 * compilation) in the lexically enclosing
48 * sub */
bb172083 49 cv_flags_t xcv_flags;
79072805 50};
748a9306 51
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52typedef struct {
53 STRLEN xpv_cur; /* length of xp_pv as a C string */
54 STRLEN xpv_len; /* allocated size */
55 union {
56 IV xivu_iv;
57 UV xivu_uv;
58 void * xivu_p1;
59 I32 xivu_i32; /* depth, >= 2 indicates recursive call */
69ecfd12 60 HEK * xivu_namehek;
c84c4652 61 } xiv_u;
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62 union {
63 MAGIC* xmg_magic; /* linked list of magicalness */
64 HV* xmg_ourstash; /* Stash for our (when SvPAD_OUR is true) */
65 } xmg_u;
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66 HV* xmg_stash; /* class package */
67
68 HV * xcv_stash;
69 union {
70 OP * xcv_start;
71 ANY xcv_xsubany;
72 } xcv_start_u;
73 union {
74 OP * xcv_root;
75 void (*xcv_xsub) (pTHX_ CV*);
76 } xcv_root_u;
77 GV * xcv_gv;
78 char * xcv_file;
79 PADLIST * xcv_padlist;
80 CV * xcv_outside;
81 U32 xcv_outside_seq; /* the COP sequence (at the point of our
82 * compilation) in the lexically enclosing
83 * sub */
84 cv_flags_t xcv_flags;
85} xpvcv_allocated;
86
954c1994 87/*
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88=head1 Handy Values
89
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90=for apidoc AmU||Nullcv
91Null CV pointer.
92
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93=head1 CV Manipulation Functions
94
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95=for apidoc Am|HV*|CvSTASH|CV* cv
96Returns the stash of the CV.
97
98=cut
99*/
100
79072805 101#define Nullcv Null(CV*)
a5f75d66 102
79072805 103#define CvSTASH(sv) ((XPVCV*)SvANY(sv))->xcv_stash
bf53b3a5 104#define CvSTART(sv) ((XPVCV*)SvANY(sv))->xcv_start_u.xcv_start
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105#define CvROOT(sv) ((XPVCV*)SvANY(sv))->xcv_root_u.xcv_root
106#define CvXSUB(sv) ((XPVCV*)SvANY(sv))->xcv_root_u.xcv_xsub
bf53b3a5 107#define CvXSUBANY(sv) ((XPVCV*)SvANY(sv))->xcv_start_u.xcv_xsubany
8990e307 108#define CvGV(sv) ((XPVCV*)SvANY(sv))->xcv_gv
57843af0 109#define CvFILE(sv) ((XPVCV*)SvANY(sv))->xcv_file
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110#ifdef USE_ITHREADS
111# define CvFILE_set_from_cop(sv, cop) (CvFILE(sv) = savepv(CopFILE(cop)))
112#else
113# define CvFILE_set_from_cop(sv, cop) (CvFILE(sv) = CopFILE(cop))
114#endif
9ec2a764 115#define CvFILEGV(sv) (gv_fetchfile(CvFILE(sv)))
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116#if defined(__GNUC__) && !defined(PERL_GCC_BRACE_GROUPS_FORBIDDEN)
117# define CvDEPTH(sv) (*({const CV *_cv = (CV *)sv; \
118 assert(SvTYPE(_cv) == SVt_PVCV); \
119 &((XPVCV*)SvANY(_cv))->xiv_u.xivu_i32; \
120 }))
121#else
122# define CvDEPTH(sv) ((XPVCV*)SvANY(sv))->xiv_u.xivu_i32
123#endif
79072805 124#define CvPADLIST(sv) ((XPVCV*)SvANY(sv))->xcv_padlist
748a9306 125#define CvOUTSIDE(sv) ((XPVCV*)SvANY(sv))->xcv_outside
a5f75d66 126#define CvFLAGS(sv) ((XPVCV*)SvANY(sv))->xcv_flags
a3985cdc 127#define CvOUTSIDE_SEQ(sv) ((XPVCV*)SvANY(sv))->xcv_outside_seq
a5f75d66 128
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129#define CVf_METHOD 0x0001 /* CV is explicitly marked as a method */
130#define CVf_LOCKED 0x0002 /* CV locks itself or first arg on entry */
131#define CVf_LVALUE 0x0004 /* CV return value can be used as lvalue */
132#define CVf_ASSERTION 0x0008 /* CV called only when asserting */
133
134#define CVf_WEAKOUTSIDE 0x0010 /* CvOUTSIDE isn't ref counted */
135#define CVf_CLONE 0x0020 /* anon CV uses external lexicals */
136#define CVf_CLONED 0x0040 /* a clone of one of those */
137#define CVf_ANON 0x0080 /* CvGV() can't be trusted */
138#define CVf_UNIQUE 0x0100 /* sub is only called once (eg PL_main_cv,
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139 * require, eval). Not to be confused
140 * with the GVf_UNIQUE flag associated
141 * with the :unique attribute */
5b4563c8 142#define CVf_NODEBUG 0x0200 /* no DB::sub indirection for this CV
8ebc5c01 143 (esp. useful for special XSUBs) */
5b4563c8 144#define CVf_CONST 0x0400 /* inlinable sub */
f73ef291 145#define CVf_ISXSUB 0x0800 /* CV is an XSUB, not pure perl. */
7dafbf52 146
d3cea301 147/* This symbol for optimised communication between toke.c and op.c: */
06492da6 148#define CVf_BUILTIN_ATTRS (CVf_METHOD|CVf_LOCKED|CVf_LVALUE|CVf_ASSERTION)
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149
150#define CvCLONE(cv) (CvFLAGS(cv) & CVf_CLONE)
151#define CvCLONE_on(cv) (CvFLAGS(cv) |= CVf_CLONE)
152#define CvCLONE_off(cv) (CvFLAGS(cv) &= ~CVf_CLONE)
153
154#define CvCLONED(cv) (CvFLAGS(cv) & CVf_CLONED)
155#define CvCLONED_on(cv) (CvFLAGS(cv) |= CVf_CLONED)
156#define CvCLONED_off(cv) (CvFLAGS(cv) &= ~CVf_CLONED)
157
158#define CvANON(cv) (CvFLAGS(cv) & CVf_ANON)
159#define CvANON_on(cv) (CvFLAGS(cv) |= CVf_ANON)
160#define CvANON_off(cv) (CvFLAGS(cv) &= ~CVf_ANON)
79072805 161
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162#define CvUNIQUE(cv) (CvFLAGS(cv) & CVf_UNIQUE)
163#define CvUNIQUE_on(cv) (CvFLAGS(cv) |= CVf_UNIQUE)
164#define CvUNIQUE_off(cv) (CvFLAGS(cv) &= ~CVf_UNIQUE)
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165
166#define CvNODEBUG(cv) (CvFLAGS(cv) & CVf_NODEBUG)
167#define CvNODEBUG_on(cv) (CvFLAGS(cv) |= CVf_NODEBUG)
168#define CvNODEBUG_off(cv) (CvFLAGS(cv) &= ~CVf_NODEBUG)
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169
170#define CvMETHOD(cv) (CvFLAGS(cv) & CVf_METHOD)
171#define CvMETHOD_on(cv) (CvFLAGS(cv) |= CVf_METHOD)
172#define CvMETHOD_off(cv) (CvFLAGS(cv) &= ~CVf_METHOD)
173
174#define CvLOCKED(cv) (CvFLAGS(cv) & CVf_LOCKED)
175#define CvLOCKED_on(cv) (CvFLAGS(cv) |= CVf_LOCKED)
176#define CvLOCKED_off(cv) (CvFLAGS(cv) &= ~CVf_LOCKED)
1aff0e91 177
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178#define CvLVALUE(cv) (CvFLAGS(cv) & CVf_LVALUE)
179#define CvLVALUE_on(cv) (CvFLAGS(cv) |= CVf_LVALUE)
180#define CvLVALUE_off(cv) (CvFLAGS(cv) &= ~CVf_LVALUE)
181
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182#define CvASSERTION(cv) (CvFLAGS(cv) & CVf_ASSERTION)
183#define CvASSERTION_on(cv) (CvFLAGS(cv) |= CVf_ASSERTION)
184#define CvASSERTION_off(cv) (CvFLAGS(cv) &= ~CVf_ASSERTION)
185
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186#define CvEVAL(cv) (CvUNIQUE(cv) && !SvFAKE(cv))
187#define CvEVAL_on(cv) (CvUNIQUE_on(cv),SvFAKE_off(cv))
188#define CvEVAL_off(cv) CvUNIQUE_off(cv)
189
bec31f9a 190/* BEGIN|CHECK|INIT|END */
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191#define CvSPECIAL(cv) (CvUNIQUE(cv) && SvFAKE(cv))
192#define CvSPECIAL_on(cv) (CvUNIQUE_on(cv),SvFAKE_on(cv))
193#define CvSPECIAL_off(cv) (CvUNIQUE_off(cv),SvFAKE_off(cv))
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194
195#define CvCONST(cv) (CvFLAGS(cv) & CVf_CONST)
196#define CvCONST_on(cv) (CvFLAGS(cv) |= CVf_CONST)
197#define CvCONST_off(cv) (CvFLAGS(cv) &= ~CVf_CONST)
a4f1a029 198
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199#define CvWEAKOUTSIDE(cv) (CvFLAGS(cv) & CVf_WEAKOUTSIDE)
200#define CvWEAKOUTSIDE_on(cv) (CvFLAGS(cv) |= CVf_WEAKOUTSIDE)
201#define CvWEAKOUTSIDE_off(cv) (CvFLAGS(cv) &= ~CVf_WEAKOUTSIDE)
202
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203#define CvISXSUB(cv) (CvFLAGS(cv) & CVf_ISXSUB)
204#define CvISXSUB_on(cv) (CvFLAGS(cv) |= CVf_ISXSUB)
205#define CvISXSUB_off(cv) (CvFLAGS(cv) &= ~CVf_ISXSUB)
206
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207/*
208=head1 CV reference counts and CvOUTSIDE
209
210=for apidoc m|bool|CvWEAKOUTSIDE|CV *cv
211
212Each CV has a pointer, C<CvOUTSIDE()>, to its lexically enclosing
213CV (if any). Because pointers to anonymous sub prototypes are
214stored in C<&> pad slots, it is a possible to get a circular reference,
215with the parent pointing to the child and vice-versa. To avoid the
216ensuing memory leak, we do not increment the reference count of the CV
217pointed to by C<CvOUTSIDE> in the I<one specific instance> that the parent
218has a C<&> pad slot pointing back to us. In this case, we set the
219C<CvWEAKOUTSIDE> flag in the child. This allows us to determine under what
220circumstances we should decrement the refcount of the parent when freeing
221the child.
222
eeb8d49e 223There is a further complication with non-closure anonymous subs (i.e. those
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DM
224that do not refer to any lexicals outside that sub). In this case, the
225anonymous prototype is shared rather than being cloned. This has the
226consequence that the parent may be freed while there are still active
227children, eg
228
229 BEGIN { $a = sub { eval '$x' } }
230
231In this case, the BEGIN is freed immediately after execution since there
232are no active references to it: the anon sub prototype has
233C<CvWEAKOUTSIDE> set since it's not a closure, and $a points to the same
234CV, so it doesn't contribute to BEGIN's refcount either. When $a is
235executed, the C<eval '$x'> causes the chain of C<CvOUTSIDE>s to be followed,
236and the freed BEGIN is accessed.
237
238To avoid this, whenever a CV and its associated pad is freed, any
239C<&> entries in the pad are explicitly removed from the pad, and if the
240refcount of the pointed-to anon sub is still positive, then that
241child's C<CvOUTSIDE> is set to point to its grandparent. This will only
242occur in the single specific case of a non-closure anon prototype
243having one or more active references (such as C<$a> above).
244
245One other thing to consider is that a CV may be merely undefined
246rather than freed, eg C<undef &foo>. In this case, its refcount may
247not have reached zero, but we still delete its pad and its C<CvROOT> etc.
248Since various children may still have their C<CvOUTSIDE> pointing at this
249undefined CV, we keep its own C<CvOUTSIDE> for the time being, so that
250the chain of lexical scopes is unbroken. For example, the following
251should print 123:
252
253 my $x = 123;
254 sub tmp { sub { eval '$x' } }
255 my $a = tmp();
256 undef &tmp;
257 print $a->();
258
259=cut
260*/
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261
262/*
263 * Local variables:
264 * c-indentation-style: bsd
265 * c-basic-offset: 4
266 * indent-tabs-mode: t
267 * End:
268 *
269 * ex: set ts=8 sts=4 sw=4 noet:
270 */