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a0d0e21e 1/* cv.h
79072805 2 *
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3 * Copyright (C) 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1999, 2000, 2001,
4 * 2002, 2003, 2004, 2005, 2006, 2007, 2008 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
f653aab7 11/* This structure must match the beginning of XPVFM in sv.h */
44a8e56a 12
79072805 13struct xpvcv {
20f4945e 14 _XPV_HEAD;
20f4945e 15 _XPVCV_COMMON;
c4648999 16 I32 xcv_depth; /* >= 2 indicates recursive call */
79072805 17};
748a9306 18
954c1994 19/*
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20=head1 Handy Values
21
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22=for apidoc AmU||Nullcv
23Null CV pointer.
24
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25(deprecated - use C<(CV *)NULL> instead)
26
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27=head1 CV Manipulation Functions
28
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29This section documents functions to manipulate CVs which are code-values,
30or subroutines. For more information, see L<perlguts>.
31
954c1994 32=for apidoc Am|HV*|CvSTASH|CV* cv
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33Returns the stash of the CV. A stash is the symbol table hash, containing
34the package-scoped variables in the package where the subroutine was defined.
35For more information, see L<perlguts>.
954c1994 36
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37This also has a special use with XS AUTOLOAD subs.
38See L<perlguts/Autoloading with XSUBs>.
39
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40=cut
41*/
42
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43#ifndef PERL_CORE
44# define Nullcv Null(CV*)
45#endif
a5f75d66 46
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47#define CvSTASH(sv) (0+((XPVCV*)MUTABLE_PTR(SvANY(sv)))->xcv_stash)
48#define CvSTASH_set(cv,st) Perl_cvstash_set(aTHX_ cv, st)
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49#define CvSTART(sv) ((XPVCV*)MUTABLE_PTR(SvANY(sv)))->xcv_start_u.xcv_start
50#define CvROOT(sv) ((XPVCV*)MUTABLE_PTR(SvANY(sv)))->xcv_root_u.xcv_root
51#define CvXSUB(sv) ((XPVCV*)MUTABLE_PTR(SvANY(sv)))->xcv_root_u.xcv_xsub
52#define CvXSUBANY(sv) ((XPVCV*)MUTABLE_PTR(SvANY(sv)))->xcv_start_u.xcv_xsubany
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53#define CvGV(sv) (0+((XPVCV*)MUTABLE_PTR(SvANY(sv)))->xcv_gv)
54#define CvGV_set(cv,gv) Perl_cvgv_set(aTHX_ cv, gv)
8f629a87 55#define CvFILE(sv) ((XPVCV*)MUTABLE_PTR(SvANY(sv)))->xcv_file
a636914a 56#ifdef USE_ITHREADS
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57# define CvFILE_set_from_cop(sv, cop) \
58 (CvFILE(sv) = savepv(CopFILE(cop)), CvDYNFILE_on(sv))
a636914a 59#else
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60# define CvFILE_set_from_cop(sv, cop) \
61 (CvFILE(sv) = CopFILE(cop), CvDYNFILE_off(sv))
a636914a 62#endif
9ec2a764 63#define CvFILEGV(sv) (gv_fetchfile(CvFILE(sv)))
bb172083 64#if defined(__GNUC__) && !defined(PERL_GCC_BRACE_GROUPS_FORBIDDEN)
8f629a87 65# define CvDEPTH(sv) (*({const CV *const _cvdepth = (const CV *)sv; \
5129b2ca 66 assert(SvTYPE(_cvdepth) == SVt_PVCV); \
c4648999 67 &((XPVCV*)SvANY(_cvdepth))->xcv_depth; \
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68 }))
69#else
c4648999 70# define CvDEPTH(sv) ((XPVCV*)MUTABLE_PTR(SvANY(sv)))->xcv_depth
bb172083 71#endif
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72#define CvPADLIST(sv) ((XPVCV*)MUTABLE_PTR(SvANY(sv)))->xcv_padlist
73#define CvOUTSIDE(sv) ((XPVCV*)MUTABLE_PTR(SvANY(sv)))->xcv_outside
74#define CvFLAGS(sv) ((XPVCV*)MUTABLE_PTR(SvANY(sv)))->xcv_flags
75#define CvOUTSIDE_SEQ(sv) ((XPVCV*)MUTABLE_PTR(SvANY(sv)))->xcv_outside_seq
a5f75d66 76
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77/* These two are sometimes called on non-CVs */
78#define CvPROTO(sv) \
79 ( \
80 SvPOK(sv) \
81 ? SvTYPE(sv) == SVt_PVCV && CvAUTOLOAD(sv) \
82 ? SvEND(sv)+1 : SvPVX_const(sv) \
83 : NULL \
84 )
85#define CvPROTOLEN(sv) \
86 ( \
87 SvPOK(sv) \
88 ? SvTYPE(sv) == SVt_PVCV && CvAUTOLOAD(sv) \
89 ? SvLEN(sv)-SvCUR(sv)-2 \
90 : SvCUR(sv) \
91 : 0 \
92 )
93
5b4563c8 94#define CVf_METHOD 0x0001 /* CV is explicitly marked as a method */
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95#define CVf_LVALUE 0x0002 /* CV return value can be used as lvalue */
96#define CVf_CONST 0x0004 /* inlinable sub */
97#define CVf_ISXSUB 0x0008 /* CV is an XSUB, not pure perl. */
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98
99#define CVf_WEAKOUTSIDE 0x0010 /* CvOUTSIDE isn't ref counted */
100#define CVf_CLONE 0x0020 /* anon CV uses external lexicals */
101#define CVf_CLONED 0x0040 /* a clone of one of those */
cfc1e951 102#define CVf_ANON 0x0080 /* CV is not pointed to by a GV */
5b4563c8 103#define CVf_UNIQUE 0x0100 /* sub is only called once (eg PL_main_cv,
1108974d 104 * require, eval). */
5b4563c8 105#define CVf_NODEBUG 0x0200 /* no DB::sub indirection for this CV
8ebc5c01 106 (esp. useful for special XSUBs) */
cfc1e951 107#define CVf_CVGV_RC 0x0400 /* CvGV is reference counted */
bad4ae38 108#define CVf_DYNFILE 0x1000 /* The filename isn't static */
8fa6a409 109#define CVf_AUTOLOAD 0x2000 /* SvPVX contains AUTOLOADed sub name */
a0d2bbd5 110#define CVf_HASEVAL 0x4000 /* contains string eval */
7dafbf52 111
d3cea301 112/* This symbol for optimised communication between toke.c and op.c: */
e95ab0c0 113#define CVf_BUILTIN_ATTRS (CVf_METHOD|CVf_LVALUE)
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114
115#define CvCLONE(cv) (CvFLAGS(cv) & CVf_CLONE)
116#define CvCLONE_on(cv) (CvFLAGS(cv) |= CVf_CLONE)
117#define CvCLONE_off(cv) (CvFLAGS(cv) &= ~CVf_CLONE)
118
119#define CvCLONED(cv) (CvFLAGS(cv) & CVf_CLONED)
120#define CvCLONED_on(cv) (CvFLAGS(cv) |= CVf_CLONED)
121#define CvCLONED_off(cv) (CvFLAGS(cv) &= ~CVf_CLONED)
122
123#define CvANON(cv) (CvFLAGS(cv) & CVf_ANON)
124#define CvANON_on(cv) (CvFLAGS(cv) |= CVf_ANON)
125#define CvANON_off(cv) (CvFLAGS(cv) &= ~CVf_ANON)
79072805 126
a2278b6a 127/* CvEVAL or CvSPECIAL */
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128#define CvUNIQUE(cv) (CvFLAGS(cv) & CVf_UNIQUE)
129#define CvUNIQUE_on(cv) (CvFLAGS(cv) |= CVf_UNIQUE)
130#define CvUNIQUE_off(cv) (CvFLAGS(cv) &= ~CVf_UNIQUE)
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131
132#define CvNODEBUG(cv) (CvFLAGS(cv) & CVf_NODEBUG)
133#define CvNODEBUG_on(cv) (CvFLAGS(cv) |= CVf_NODEBUG)
134#define CvNODEBUG_off(cv) (CvFLAGS(cv) &= ~CVf_NODEBUG)
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135
136#define CvMETHOD(cv) (CvFLAGS(cv) & CVf_METHOD)
137#define CvMETHOD_on(cv) (CvFLAGS(cv) |= CVf_METHOD)
138#define CvMETHOD_off(cv) (CvFLAGS(cv) &= ~CVf_METHOD)
139
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140#define CvLVALUE(cv) (CvFLAGS(cv) & CVf_LVALUE)
141#define CvLVALUE_on(cv) (CvFLAGS(cv) |= CVf_LVALUE)
142#define CvLVALUE_off(cv) (CvFLAGS(cv) &= ~CVf_LVALUE)
143
a2278b6a 144/* eval or PL_main_cv */
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145#define CvEVAL(cv) (CvUNIQUE(cv) && !SvFAKE(cv))
146#define CvEVAL_on(cv) (CvUNIQUE_on(cv),SvFAKE_off(cv))
147#define CvEVAL_off(cv) CvUNIQUE_off(cv)
148
3c10abe3 149/* BEGIN|CHECK|INIT|UNITCHECK|END */
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150#define CvSPECIAL(cv) (CvUNIQUE(cv) && SvFAKE(cv))
151#define CvSPECIAL_on(cv) (CvUNIQUE_on(cv),SvFAKE_on(cv))
152#define CvSPECIAL_off(cv) (CvUNIQUE_off(cv),SvFAKE_off(cv))
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153
154#define CvCONST(cv) (CvFLAGS(cv) & CVf_CONST)
155#define CvCONST_on(cv) (CvFLAGS(cv) |= CVf_CONST)
156#define CvCONST_off(cv) (CvFLAGS(cv) &= ~CVf_CONST)
a4f1a029 157
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158#define CvWEAKOUTSIDE(cv) (CvFLAGS(cv) & CVf_WEAKOUTSIDE)
159#define CvWEAKOUTSIDE_on(cv) (CvFLAGS(cv) |= CVf_WEAKOUTSIDE)
160#define CvWEAKOUTSIDE_off(cv) (CvFLAGS(cv) &= ~CVf_WEAKOUTSIDE)
161
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162#define CvISXSUB(cv) (CvFLAGS(cv) & CVf_ISXSUB)
163#define CvISXSUB_on(cv) (CvFLAGS(cv) |= CVf_ISXSUB)
164#define CvISXSUB_off(cv) (CvFLAGS(cv) &= ~CVf_ISXSUB)
165
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166#define CvCVGV_RC(cv) (CvFLAGS(cv) & CVf_CVGV_RC)
167#define CvCVGV_RC_on(cv) (CvFLAGS(cv) |= CVf_CVGV_RC)
168#define CvCVGV_RC_off(cv) (CvFLAGS(cv) &= ~CVf_CVGV_RC)
169
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170#define CvDYNFILE(cv) (CvFLAGS(cv) & CVf_DYNFILE)
171#define CvDYNFILE_on(cv) (CvFLAGS(cv) |= CVf_DYNFILE)
172#define CvDYNFILE_off(cv) (CvFLAGS(cv) &= ~CVf_DYNFILE)
173
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174#define CvAUTOLOAD(cv) (CvFLAGS(cv) & CVf_AUTOLOAD)
175#define CvAUTOLOAD_on(cv) (CvFLAGS(cv) |= CVf_AUTOLOAD)
176#define CvAUTOLOAD_off(cv) (CvFLAGS(cv) &= ~CVf_AUTOLOAD)
177
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178#define CvHASEVAL(cv) (CvFLAGS(cv) & CVf_HASEVAL)
179#define CvHASEVAL_on(cv) (CvFLAGS(cv) |= CVf_HASEVAL)
180#define CvHASEVAL_off(cv) (CvFLAGS(cv) &= ~CVf_HASEVAL)
181
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182/* Flags for newXS_flags */
183#define XS_DYNAMIC_FILENAME 0x01 /* The filename isn't static */
184
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185/*
186=head1 CV reference counts and CvOUTSIDE
187
188=for apidoc m|bool|CvWEAKOUTSIDE|CV *cv
189
190Each CV has a pointer, C<CvOUTSIDE()>, to its lexically enclosing
191CV (if any). Because pointers to anonymous sub prototypes are
192stored in C<&> pad slots, it is a possible to get a circular reference,
193with the parent pointing to the child and vice-versa. To avoid the
194ensuing memory leak, we do not increment the reference count of the CV
195pointed to by C<CvOUTSIDE> in the I<one specific instance> that the parent
196has a C<&> pad slot pointing back to us. In this case, we set the
197C<CvWEAKOUTSIDE> flag in the child. This allows us to determine under what
198circumstances we should decrement the refcount of the parent when freeing
199the child.
200
eeb8d49e 201There is a further complication with non-closure anonymous subs (i.e. those
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202that do not refer to any lexicals outside that sub). In this case, the
203anonymous prototype is shared rather than being cloned. This has the
204consequence that the parent may be freed while there are still active
205children, eg
206
207 BEGIN { $a = sub { eval '$x' } }
208
209In this case, the BEGIN is freed immediately after execution since there
210are no active references to it: the anon sub prototype has
211C<CvWEAKOUTSIDE> set since it's not a closure, and $a points to the same
212CV, so it doesn't contribute to BEGIN's refcount either. When $a is
213executed, the C<eval '$x'> causes the chain of C<CvOUTSIDE>s to be followed,
214and the freed BEGIN is accessed.
215
216To avoid this, whenever a CV and its associated pad is freed, any
217C<&> entries in the pad are explicitly removed from the pad, and if the
218refcount of the pointed-to anon sub is still positive, then that
219child's C<CvOUTSIDE> is set to point to its grandparent. This will only
220occur in the single specific case of a non-closure anon prototype
221having one or more active references (such as C<$a> above).
222
223One other thing to consider is that a CV may be merely undefined
224rather than freed, eg C<undef &foo>. In this case, its refcount may
225not have reached zero, but we still delete its pad and its C<CvROOT> etc.
226Since various children may still have their C<CvOUTSIDE> pointing at this
227undefined CV, we keep its own C<CvOUTSIDE> for the time being, so that
228the chain of lexical scopes is unbroken. For example, the following
229should print 123:
230
231 my $x = 123;
232 sub tmp { sub { eval '$x' } }
233 my $a = tmp();
234 undef &tmp;
235 print $a->();
236
237=cut
238*/
102d3b8a 239
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240typedef OP *(*Perl_call_checker)(pTHX_ OP *, GV *, SV *);
241
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242/*
243 * Local variables:
244 * c-indentation-style: bsd
245 * c-basic-offset: 4
14d04a33 246 * indent-tabs-mode: nil
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247 * End:
248 *
14d04a33 249 * ex: set ts=8 sts=4 sw=4 et:
102d3b8a 250 */