perlintern - autogenerated documentation of purelyinternal Perl functions
This file is the autogenerated documentation of functions in the Perl interpreter that are documented using Perl's internal documentation format but are not marked as part of the Perl API. In other words,they are not for use in extensions!
NOTE: this function is experimental and may change or be removed without notice.
Return an entry from the BHK structure.which is a preprocessor token indicating which entry to return. If the appropriate flag is not set this will returnNULL. The type of the return value depends on which entry you ask for.
void *BhkENTRY(BHK *hk, which)NOTE: this function is experimental and may change or be removed without notice.
Return the BHK's flags.
U32BhkFLAGS(BHK *hk)NOTE: this function is experimental and may change or be removed without notice.
Call all the registered block hooks for typewhich.which is a preprocessing token; the type ofarg depends onwhich.
voidCALL_BLOCK_HOOKS(which, arg)This function assigns the prototype of the named core function tosv, or to a new mortal SV ifsv isNULL. It returns the modifiedsv, orNULL if the core function has no prototype.code is a code as returned bykeyword(). It must not be equal to 0.
SV *core_prototype(SV *sv, const char *name, const int code, int * const opnum)Check for the cases 0 or 3 of cur_env.je_ret, only used inside an eval context.
0 is used as continue inside eval,
3 is used for a die caught by an inner eval - continue inner loop
Seecop.h: je_mustcatch, when set at any runlevel to TRUE, means eval ops must establish a local jmpenv to handle exception traps.
OP*docatch(Perl_ppaddr_t firstpp)Each CV has a pointer,CvOUTSIDE(), to its lexically enclosing CV (if any). Because pointers to anonymous sub prototypes are stored in& pad slots, it is a possible to get a circular reference, with the parent pointing to the child and vice-versa. To avoid the ensuing memory leak, we do not increment the reference count of the CV pointed to byCvOUTSIDE in theone specific instance that the parent has a& pad slot pointing back to us. In this case, we set theCvWEAKOUTSIDE flag in the child. This allows us to determine under what circumstances we should decrement the refcount of the parent when freeing the child.
There is a further complication with non-closure anonymous subs (i.e. those that do not refer to any lexicals outside that sub). In this case, the anonymous prototype is shared rather than being cloned. This has the consequence that the parent may be freed while there are still active children,e.g.,
BEGIN { $a = sub { eval '$x' } }In this case, the BEGIN is freed immediately after execution since there are no active references to it: the anon sub prototype hasCvWEAKOUTSIDE set since it's not a closure, and $a points to the same CV, so it doesn't contribute to BEGIN's refcount either. When $a is executed, theeval '$x' causes the chain ofCvOUTSIDEs to be followed, and the freed BEGIN is accessed.
To avoid this, whenever a CV and its associated pad is freed, any& entries in the pad are explicitly removed from the pad, and if the refcount of the pointed-to anon sub is still positive, then that child'sCvOUTSIDE is set to point to its grandparent. This will only occur in the single specific case of a non-closure anon prototype having one or more active references (such as$a above).
One other thing to consider is that a CV may be merely undefined rather than freed, egundef &foo. In this case, its refcount may not have reached zero, but we still delete its pad and itsCvROOT etc. Since various children may still have theirCvOUTSIDE pointing at this undefined CV, we keep its ownCvOUTSIDE for the time being, so that the chain of lexical scopes is unbroken. For example, the following should print 123:
my $x = 123; sub tmp { sub { eval '$x' } } my $a = tmp(); undef &tmp; print $a->();boolCvWEAKOUTSIDE(CV *cv)dump the contents of a CV
voidcv_dump(CV *cv, const char *title)When a CV has a reference count on its slab (CvSLABBED), it is responsible for making sure it is freed. (Hence, no two CVs should ever have a reference count on the same slab.) The CV only needs to reference the slab during compilation. Once it is compiled andCvROOT attached, it has finished its job, so it can forget the slab.
voidcv_forget_slab(CV *cv)Dump the contents of a padlist
voiddo_dump_pad(I32 level, PerlIO *file, PADLIST *padlist, int full)Allocates a place in the currently-compiling pad (via"pad_alloc" in perlapi) and then stores a name for that entry.name is adopted and becomes the name entry; it must already contain the name string.typestash andourstash and thepadadd_STATE flag get added toname. None of the other processing of"pad_add_name_pvn" in perlapi is done. Returns the offset of the allocated pad slot.
PADOFFSET pad_alloc_name(PADNAME *name, U32 flags, HV *typestash, HV *ourstash)Update the pad compilation state variables on entry to a new block.
voidpad_block_start(int full)Check for duplicate declarations: report any of:
* a 'my' in the current scope with the same name;* an 'our' (anywhere in the pad) with the same name and the same stash as 'ourstash'is_our indicates that the name to check is an"our" declaration.
voidpad_check_dup(PADNAME *name, U32 flags, const HV *ourstash)Find a named lexical anywhere in a chain of nested pads. Add fake entries in the inner pads if it's found in an outer one.
Returns the offset in the bottom pad of the lex or the fake lex.cv is the CV in which to start the search, and seq is the currentcop_seq to match against. Ifwarn is true, print appropriate warnings. Theout_* vars return values, and so are pointers to where the returned values should be stored.out_capture, if non-null, requests that the innermost instance of the lexical is captured;out_name is set to the innermost matched pad name or fake pad name;out_flags returns the flags normally associated with thePARENT_FAKELEX_FLAGS field of a fake pad name.
Note thatpad_findlex() is recursive; it recurses up the chain of CVs, then comes back down, adding fake entries as it goes. It has to be this way because fake names in anon protoypes have to store inxpadn_low the index into the parent pad.
PADOFFSET pad_findlex(const char *namepv, STRLEN namelen, U32 flags, const CV* cv, U32 seq, int warn, SV** out_capture, PADNAME** out_name, int *out_flags)For any anon CVs in the pad, changeCvOUTSIDE of that CV fromold_cv tonew_cv if necessary. Needed when a newly-compiled CV has to be moved to a pre-existing CV struct.
voidpad_fixup_inner_anons(PADLIST *padlist, CV *old_cv, CV *new_cv)Free the SV at offset po in the current pad.
voidpad_free(PADOFFSET po)Cleanup at end of scope during compilation: set the max seq number for lexicals in this scope and warn of any lexicals that never got introduced.
voidpad_leavemy()Duplicates a pad.
PADLIST * padlist_dup(PADLIST *srcpad, CLONE_PARAMS *param)Duplicates a pad name.
PADNAME * padname_dup(PADNAME *src, CLONE_PARAMS *param)Duplicates a pad name list.
PADNAMELIST * padnamelist_dup(PADNAMELIST *srcpad, CLONE_PARAMS *param)Push a new pad frame onto the padlist, unless there's already a pad at this depth, in which case don't bother creating a new one. Then give the new pad an@_ in slot zero.
voidpad_push(PADLIST *padlist, int depth)Mark all the current temporaries for reuse
voidpad_reset()Abandon the tmp in the current pad at offsetpo and replace with a new one.
voidpad_swipe(PADOFFSET po, bool refadjust)NOTE: this function is experimental and may change or be removed without notice.
If the typeglobgv can be expressed more succinctly, by having something other than a real GV in its place in the stash, replace it with the optimised form. Basic requirements for this are thatgv is a real typeglob, is sufficiently ordinary, and is only referenced from its package. This function is meant to be used when a GV has been looked up in part to see what was there, causing upgrading, but based on what was found it turns out that the real GV isn't required after all.
Ifgv is a completely empty typeglob, it is deleted from the stash.
Ifgv is a typeglob containing only a sufficiently-ordinary constant sub, the typeglob is replaced with a scalar-reference placeholder that more compactly represents the same thing.
voidgv_try_downgrade(GV* gv)Adds a name to a stash's internal list of effective names. See"hv_ename_delete".
This is called when a stash is assigned to a new location in the symbol table.
voidhv_ename_add(HV *hv, const char *name, U32 len, U32 flags)Removes a name from a stash's internal list of effective names. If this is the name returned byHvENAME, then another name in the list will take its place (HvENAME will use it).
This is called when a stash is deleted from the symbol table.
voidhv_ename_delete(HV *hv, const char *name, U32 len, U32 flags)Generates and returns aHV * representing the content of arefcounted_he chain.flags is currently unused and must be zero.
HV *refcounted_he_chain_2hv( const struct refcounted_he *c, U32 flags)Like"refcounted_he_fetch_pvn", but takes a nul-terminated string instead of a string/length pair.
SV *refcounted_he_fetch_pv( const struct refcounted_he *chain, const char *key, U32 hash, U32 flags)Search along arefcounted_he chain for an entry with the key specified bykeypv andkeylen. Ifflags has theREFCOUNTED_HE_KEY_UTF8 bit set, the key octets are interpreted as UTF-8, otherwise they are interpreted as Latin-1.hash is a precomputed hash of the key string, or zero if it has not been precomputed. Returns a mortal scalar representing the value associated with the key, or&PL_sv_placeholder if there is no value associated with the key.
SV *refcounted_he_fetch_pvn( const struct refcounted_he *chain, const char *keypv, STRLEN keylen, U32 hash, U32 flags)Like"refcounted_he_fetch_pvn", but takes a literal string instead of a string/length pair, and no precomputed hash.
SV *refcounted_he_fetch_pvs( const struct refcounted_he *chain, "literal string" key, U32 flags)Like"refcounted_he_fetch_pvn", but takes a Perl scalar instead of a string/length pair.
SV *refcounted_he_fetch_sv( const struct refcounted_he *chain, SV *key, U32 hash, U32 flags)Decrements the reference count of arefcounted_he by one. If the reference count reaches zero the structure's memory is freed, which (recursively) causes a reduction of its parentrefcounted_he's reference count. It is safe to pass a null pointer to this function: no action occurs in this case.
voidrefcounted_he_free(struct refcounted_he *he)Increment the reference count of arefcounted_he. The pointer to therefcounted_he is also returned. It is safe to pass a null pointer to this function: no action occurs and a null pointer is returned.
struct refcounted_he * refcounted_he_inc( struct refcounted_he *he )Like"refcounted_he_new_pvn", but takes a nul-terminated string instead of a string/length pair.
struct refcounted_he * refcounted_he_new_pv( struct refcounted_he *parent, const char *key, U32 hash, SV *value, U32 flags )Creates a newrefcounted_he. This consists of a single key/value pair and a reference to an existingrefcounted_he chain (which may be empty), and thus forms a longer chain. When using the longer chain, the new key/value pair takes precedence over any entry for the same key further along the chain.
The new key is specified bykeypv andkeylen. Ifflags has theREFCOUNTED_HE_KEY_UTF8 bit set, the key octets are interpreted as UTF-8, otherwise they are interpreted as Latin-1.hash is a precomputed hash of the key string, or zero if it has not been precomputed.
value is the scalar value to store for this key.value is copied by this function, which thus does not take ownership of any reference to it, and later changes to the scalar will not be reflected in the value visible in therefcounted_he. Complex types of scalar will not be stored with referential integrity, but will be coerced to strings.value may be either null or&PL_sv_placeholder to indicate that no value is to be associated with the key; this, as with any non-null value, takes precedence over the existence of a value for the key further along the chain.
parent points to the rest of therefcounted_he chain to be attached to the newrefcounted_he. This function takes ownership of one reference toparent, and returns one reference to the newrefcounted_he.
struct refcounted_he * refcounted_he_new_pvn( struct refcounted_he *parent, const char *keypv, STRLEN keylen, U32 hash, SV *value, U32 flags )Like"refcounted_he_new_pvn", but takes a literal string instead of a string/length pair, and no precomputed hash.
struct refcounted_he * refcounted_he_new_pvs( struct refcounted_he *parent, "literal string" key, SV *value, U32 flags )Like"refcounted_he_new_pvn", but takes a Perl scalar instead of a string/length pair.
struct refcounted_he * refcounted_he_new_sv( struct refcounted_he *parent, SV *key, U32 hash, SV *value, U32 flags )NOTE: this function is experimental and may change or be removed without notice.
Function called bydo_readline to spawn a glob (or do the glob inside perl on VMS). This code used to be inline, but now perl usesFile::Glob this glob starter is only used by miniperl during the build process, or when PERL_EXTERNAL_GLOB is defined. Moving it away shrinkspp_hot.c; shrinkingpp_hot.c helps speed perl up.
PerlIO*start_glob(SV *tmpglob, IO *io)NOTE: this function is experimental and may change or be removed without notice.
This function performs syntax checking on a prototype,proto. Ifwarn is true, any illegal characters or mismatched brackets will trigger illegalproto warnings, declaring that they were detected in the prototype forname.
The return value istrue if this is a valid prototype, andfalse if it is not, regardless of whetherwarn wastrue orfalse.
Note thatNULL is a validproto and will always returntrue.
NOTE: the perl_ form of this function is deprecated.
boolvalidate_proto(SV *name, SV *proto, bool warn, bool curstash)Triggered by a delete from%^H, records the key toPL_compiling.cop_hints_hash.
intmagic_clearhint(SV* sv, MAGIC* mg)Triggered by clearing%^H, resetsPL_compiling.cop_hints_hash.
intmagic_clearhints(SV* sv, MAGIC* mg)Invoke a magic method (like FETCH).
sv andmg are the tied thingy and the tie magic.
meth is the name of the method to call.
argc is the number of args (in addition to $self) to pass to the method.
Theflags can be:
G_DISCARD invoke method with G_DISCARD flag and don't return a valueG_UNDEF_FILL fill the stack with argc pointers to PL_sv_undefThe arguments themselves are any values following theflags argument.
Returns the SV (if any) returned by the method, orNULL on failure.
SV*magic_methcall(SV *sv, const MAGIC *mg, SV *meth, U32 flags, U32 argc, ...)Triggered by a store to%^H, records the key/value pair toPL_compiling.cop_hints_hash. It is assumed that hints aren't storing anything that would need a deep copy. Maybe we should warn if we find a reference.
intmagic_sethint(SV* sv, MAGIC* mg)Copy some of the magic from an existing SV to new localized version of that SV. Container magic (e.g.,%ENV,$1,tie) gets copied, value magic doesn't (e.g.,taint,pos).
Ifsetmagic is false then no set magic will be called on the new (empty) SV. This typically means that assignment will soon follow (e.g.'local $x = $y'), and that will handle the magic.
voidmg_localize(SV* sv, SV* nsv, bool setmagic)Deallocates a backtrace received from get_c_bracktrace.
voidfree_c_backtrace(Perl_c_backtrace* bt)Collects the backtrace (aka "stacktrace") into a single linear malloced buffer, which the callermustPerl_free_c_backtrace().
Scans the frames back bydepth + skip, then drops theskip innermost, returning at mostdepth frames.
Perl_c_backtrace* get_c_backtrace(int max_depth, int skip)Returns the Depth-First Search linearization of@ISA the given stash. The return value is a read-only AV*.level should be 0 (it is used internally in this function's recursion).
You are responsible forSvREFCNT_inc() on the return value if you plan to store it anywhere semi-permanently (otherwise it might be deleted out from under you the next time the cache is invalidated).
AV*mro_get_linear_isa_dfs(HV* stash, U32 level)Takes the necessary steps (cache invalidations, mostly) when the@ISA of the given package has changed. Invoked by thesetisa magic, should not need to invoke directly.
voidmro_isa_changed_in(HV* stash)Call this function to signal to a stash that it has been assigned to another spot in the stash hierarchy.stash is the stash that has been assigned.oldstash is the stash it replaces, if any.gv is the glob that is actually being assigned to.
This can also be called with a null first argument to indicate thatoldstash has been deleted.
This function invalidates isa caches on the old stash, on all subpackages nested inside it, and on the subclasses of all those, including non-existent packages that have corresponding entries instash.
It also sets the effective names (HvENAME) on all the stashes as appropriate.
If thegv is present and is not in the symbol table, then this function simply returns. This checked will be skipped ifflags & 1.
voidmro_package_moved(HV * const stash, HV * const oldstash, const GV * const gv, U32 flags)parse a string, looking for a decimal unsigned integer.
On entry,pv points to the beginning of the string;valptr points to a UV that will receive the converted value, if found;endptr is either NULL or points to a variable that points to one byte beyond the point inpv that this routine should examine. Ifendptr is NULL,pv is assumed to be NUL-terminated.
Returns FALSE ifpv doesn't represent a valid unsigned integer value (with no leading zeros). Otherwise it returns TRUE, and sets*valptr to that value.
If you constrain the portion ofpv that is looked at by this function (by passing a non-NULLendptr), and if the intial bytes of that portion form a valid value, it will return TRUE, setting*endptr to the byte following the final digit of the value. But if there is no constraint at what's looked at, all ofpv must be valid in order for TRUE to be returned.
The only characters this accepts are the decimal digits '0'..'9'.
As opposed toatoi(3) orstrtol(3),grok_atoUV does NOT allow optional leading whitespace, nor negative inputs. If such features are required, the calling code needs to explicitly implement those.
Note that this function returns FALSE for inputs that would overflow a UV, or have leading zeros. Thus a single0 is accepted, but not00 nor01,002,etc.
Background:atoi has severe problems with illegal inputs, it cannot be used for incremental parsing, and therefore should be avoidedatoi andstrtol are also affected by locale settings, which can also be seen as a bug (global state controlled by user environment).
boolgrok_atoUV(const char* pv, UV* valptr, const char** endptr)This function finalizes the optree. Should be called directly after the complete optree is built. It does some additional checking which can't be done in the normalck_xxx functions and makes the tree thread-safe.
voidfinalize_optree(OP* o)Construct a Perl subroutine, also performing some surrounding jobs.
This function is expected to be called in a Perl compilation context, and some aspects of the subroutine are taken from global variables associated with compilation. In particular,PL_compcv represents the subroutine that is currently being compiled. It must be non-null when this function is called, and some aspects of the subroutine being constructed are taken from it. The constructed subroutine may actually be a reuse of thePL_compcv object, but will not necessarily be so.
Ifblock is null then the subroutine will have no body, and for the time being it will be an error to call it. This represents a forward subroutine declaration such assub foo ($$);. Ifblock is non-null then it provides the Perl code of the subroutine body, which will be executed when the subroutine is called. This body includes any argument unwrapping code resulting from a subroutine signature or similar. The pad use of the code must correspond to the pad attached toPL_compcv. The code is not expected to include aleavesub orleavesublv op; this function will add such an op.block is consumed by this function and will become part of the constructed subroutine.
proto specifies the subroutine's prototype, unless one is supplied as an attribute (see below). Ifproto is null, then the subroutine will not have a prototype. Ifproto is non-null, it must point to aconst op whose value is a string, and the subroutine will have that string as its prototype. If a prototype is supplied as an attribute, the attribute takes precedence overproto, but in that caseproto should preferably be null. In any case,proto is consumed by this function.
attrs supplies attributes to be applied the subroutine. A handful of attributes take effect by built-in means, being applied toPL_compcv immediately when seen. Other attributes are collected up and attached to the subroutine by this route.attrs may be null to supply no attributes, or point to aconst op for a single attribute, or point to alist op whose children apart from thepushmark areconst ops for one or more attributes. Eachconst op must be a string, giving the attribute name optionally followed by parenthesised arguments, in the manner in which attributes appear in Perl source. The attributes will be applied to the sub by this function.attrs is consumed by this function.
Ifo_is_gv is false ando is null, then the subroutine will be anonymous. Ifo_is_gv is false ando is non-null, theno must point to aconst op, which will be consumed by this function, and its string value supplies a name for the subroutine. The name may be qualified or unqualified, and if it is unqualified then a default stash will be selected in some manner. Ifo_is_gv is true, theno doesn't point to anOP at all, but is instead a cast pointer to aGV by which the subroutine will be named.
If there is already a subroutine of the specified name, then the new sub will either replace the existing one in the glob or be merged with the existing one. A warning may be generated about redefinition.
If the subroutine has one of a few special names, such asBEGIN orEND, then it will be claimed by the appropriate queue for automatic running of phase-related subroutines. In this case the relevant glob will be left not containing any subroutine, even if it did contain one before. In the case ofBEGIN, the subroutine will be executed and the reference to it disposed of before this function returns.
The function returns a pointer to the constructed subroutine. If the sub is anonymous then ownership of one counted reference to the subroutine is transferred to the caller. If the sub is named then the caller does not get ownership of a reference. In most such cases, where the sub has a non-phase name, the sub will be alive at the point it is returned by virtue of being contained in the glob that names it. A phase-named subroutine will usually be alive by virtue of the reference owned by the phase's automatic run queue. But aBEGIN subroutine, having already been executed, will quite likely have been destroyed already by the time this function returns, making it erroneous for the caller to make any use of the returned pointer. It is the caller's responsibility to ensure that it knows which of these situations applies.
CV *newATTRSUB_x(I32 floor, OP *o, OP *proto, OP *attrs, OP *block, bool o_is_gv)Construct an XS subroutine, also performing some surrounding jobs.
The subroutine will have the entry pointsubaddr. It will have the prototype specified by the nul-terminated stringproto, or no prototype ifproto is null. The prototype string is copied; the caller can mutate the supplied string afterwards. Iffilename is non-null, it must be a nul-terminated filename, and the subroutine will have itsCvFILE set accordingly. By defaultCvFILE is set to point directly to the supplied string, which must be static. Ifflags has theXS_DYNAMIC_FILENAME bit set, then a copy of the string will be taken instead.
Other aspects of the subroutine will be left in their default state. If anything else needs to be done to the subroutine for it to function correctly, it is the caller's responsibility to do that after this function has constructed it. However, beware of the subroutine potentially being destroyed before this function returns, as described below.
Ifname is null then the subroutine will be anonymous, with itsCvGV referring to an__ANON__ glob. Ifname is non-null then the subroutine will be named accordingly, referenced by the appropriate glob.name is a string of lengthlen bytes giving a sigilless symbol name, in UTF-8 ifflags has theSVf_UTF8 bit set and in Latin-1 otherwise. The name may be either qualified or unqualified, with the stash defaulting in the same manner as forgv_fetchpvn_flags.flags may contain flag bits understood bygv_fetchpvn_flags with the same meaning as they have there, such asGV_ADDWARN. The symbol is always added to the stash if necessary, withGV_ADDMULTI semantics.
If there is already a subroutine of the specified name, then the new sub will replace the existing one in the glob. A warning may be generated about the redefinition. If the old subroutine wasCvCONST then the decision about whether to warn is influenced by an expectation about whether the new subroutine will become a constant of similar value. That expectation is determined byconst_svp. (Note that the call to this function doesn't make the new subroutineCvCONST in any case; that is left to the caller.) Ifconst_svp is null then it indicates that the new subroutine will not become a constant. Ifconst_svp is non-null then it indicates that the new subroutine will become a constant, and it points to anSV* that provides the constant value that the subroutine will have.
If the subroutine has one of a few special names, such asBEGIN orEND, then it will be claimed by the appropriate queue for automatic running of phase-related subroutines. In this case the relevant glob will be left not containing any subroutine, even if it did contain one before. In the case ofBEGIN, the subroutine will be executed and the reference to it disposed of before this function returns, and also before its prototype is set. If aBEGIN subroutine would not be sufficiently constructed by this function to be ready for execution then the caller must prevent this happening by giving the subroutine a different name.
The function returns a pointer to the constructed subroutine. If the sub is anonymous then ownership of one counted reference to the subroutine is transferred to the caller. If the sub is named then the caller does not get ownership of a reference. In most such cases, where the sub has a non-phase name, the sub will be alive at the point it is returned by virtue of being contained in the glob that names it. A phase-named subroutine will usually be alive by virtue of the reference owned by the phase's automatic run queue. But aBEGIN subroutine, having already been executed, will quite likely have been destroyed already by the time this function returns, making it erroneous for the caller to make any use of the returned pointer. It is the caller's responsibility to ensure that it knows which of these situations applies.
CV *newXS_len_flags(const char *name, STRLEN len, XSUBADDR_t subaddr, const char *const filename, const char *const proto, SV **const_svp, U32 flags)This function applies some optimisations to the optree in top-down order. It is called before the peephole optimizer, which processes ops in execution order. Note that finalize_optree() also does a top-down scan, but is called *after* the peephole optimizer.
voidoptimize_optree(OP* o)Return the next op in a depth-first traversal of the op tree, returning NULL when the traversal is complete.
The initial call must supply the root of the tree as both top and o.
For now it's static, but it may be exposed to the API in the future.
traverse_op_tree;Save the current pad in the given context block structure.
voidCX_CURPAD_SAVE(struct context)Access the SV at offsetpo in the saved current pad in the given context block structure (can be used as an lvalue).
SV *CX_CURPAD_SV(struct context, PADOFFSET po)Get the value from slotpo in the base (DEPTH=1) pad of a padlist
SV *PAD_BASE_SV(PADLIST padlist, PADOFFSET po)Clone the state variables associated with running and compiling pads.
voidPAD_CLONE_VARS(PerlInterpreter *proto_perl, CLONE_PARAMS* param)Return the flags for the current compiling pad name at offsetpo. Assumes a valid slot entry.
U32PAD_COMPNAME_FLAGS(PADOFFSET po)The generation number of the name at offsetpo in the current compiling pad (lvalue).
STRLENPAD_COMPNAME_GEN(PADOFFSET po)Sets the generation number of the name at offsetpo in the current ling pad (lvalue) togen. STRLEN PAD_COMPNAME_GEN_set(PADOFFSET po, int gen)
Return the stash associated with anour variable. Assumes the slot entry is a validour lexical.
HV *PAD_COMPNAME_OURSTASH(PADOFFSET po)Return the name of the current compiling pad name at offsetpo. Assumes a valid slot entry.
char *PAD_COMPNAME_PV(PADOFFSET po)Return the type (stash) of the current compiling pad name at offsetpo. Must be a valid name. Returns null if not typed.
HV *PAD_COMPNAME_TYPE(PADOFFSET po)Whether this is an "our" variable.
boolPadnameIsOUR(PADNAME pn)Whether this is a "state" variable.
boolPadnameIsSTATE(PADNAME pn)The stash in which this "our" variable was declared.
HV *PadnameOURSTASH()Whether this entry belongs to an outer pad. Entries for which this is true are often referred to as 'fake'.
boolPadnameOUTER(PADNAME pn)The stash associated with a typed lexical. This returns the%Foo:: hash formy Foo $bar.
HV *PadnameTYPE(PADNAME pn)Restore the old pad saved into the local variableopad byPAD_SAVE_LOCAL()
voidPAD_RESTORE_LOCAL(PAD *opad)Save the current pad to the local variableopad, then make the current pad equal tonpad
voidPAD_SAVE_LOCAL(PAD *opad, PAD *npad)Save the current pad then set it to null.
voidPAD_SAVE_SETNULLPAD()Set the slot at offsetpo in the current pad tosv
SV *PAD_SETSV(PADOFFSET po, SV* sv)Set the current pad to be padn in the padlist, saving the previous current pad. NB currently this macro expands to a string too long for some compilers, so it's best to replace it with
SAVECOMPPAD(); PAD_SET_CUR_NOSAVE(padlist,n);voidPAD_SET_CUR(PADLIST padlist, I32 n)like PAD_SET_CUR, but without the save
voidPAD_SET_CUR_NOSAVE(PADLIST padlist, I32 n)Get the value at offsetpo in the current pad
SV *PAD_SV(PADOFFSET po)Lightweight and lvalue version ofPAD_SV. Get or set the value at offsetpo in the current pad. UnlikePAD_SV, does not print diagnostics with -DX. For internal use only.
SV *PAD_SVl(PADOFFSET po)Clear the pointed to pad value on scope exit. (i.e. the runtime action ofmy)
voidSAVECLEARSV(SV **svp)savePL_comppad andPL_curpad
voidSAVECOMPPAD()Save a pad slot (used to restore after an iteration)
XXX DAPM it would make more sense to make the arg a PADOFFSET void SAVEPADSV(PADOFFSET po)
When Perl is run in debugging mode, with the-d switch, this SV is a boolean which indicates whether subs are being single-stepped. Single-stepping is automatically turned on after every step. This is the C variable which corresponds to Perl's $DB::single variable. See"PL_DBsub".
SV *PL_DBsingleWhen Perl is run in debugging mode, with the-d switch, this GV contains the SV which holds the name of the sub being debugged. This is the C variable which corresponds to Perl's $DB::sub variable. See"PL_DBsingle".
GV *PL_DBsubTrace variable used when Perl is run in debugging mode, with the-d switch. This is the C variable which corresponds to Perl's $DB::trace variable. See"PL_DBsingle".
SV *PL_DBtraceThe C variable that roughly corresponds to Perl's$^W warning variable. However,$^W is treated as a boolean, whereasPL_dowarn is a collection of flag bits.
U8PL_dowarnThe GV which was last used for a filehandle input operation. (<FH>)
GV*PL_last_in_gvThe glob containing the output field separator -*, in Perl space.
GV*PL_ofsgvThe input record separator -$/ in Perl space.
SV*PL_rsDeclare JustSP. This is actually identical todSP, and declares a local copy of perl's stack pointer, available via theSP macro. See"SP" in perlapi. (Available for backward source code compatibility with the old (Perl 5.005) thread model.)
djSP;True if this op will be the return value of an lvalue subroutine
An SV (or AV, HV, etc.) is allocated in two parts: the head (struct sv, av, hv...) contains type and reference count information, and for many types, a pointer to the body (struct xrv, xpv, xpviv...), which contains fields specific to each type. Some types store all they need in the head, so don't have a body.
In all but the most memory-paranoid configurations (ex: PURIFY), heads and bodies are allocated out of arenas, which by default are approximately 4K chunks of memory parcelled up into N heads or bodies. Sv-bodies are allocated by their sv-type, guaranteeing size consistency needed to allocate safely from arrays.
For SV-heads, the first slot in each arena is reserved, and holds a link to the next arena, some flags, and a note of the number of slots. Snaked through each arena chain is a linked list of free items; when this becomes empty, an extra arena is allocated and divided up into N items which are threaded into the free list.
SV-bodies are similar, but they use arena-sets by default, which separate the link and info from the arena itself, and reclaim the 1st slot in the arena. SV-bodies are further described later.
The following global variables are associated with arenas:
PL_sv_arenaroot pointer to list of SV arenasPL_sv_root pointer to list of free SV structuresPL_body_arenas head of linked-list of body arenasPL_body_roots[] array of pointers to list of free bodies of svtype arrays are indexed by the svtype neededA few special SV heads are not allocated from an arena, but are instead directly created in the interpreter structure, eg PL_sv_undef. The size of arenas can be changed from the default by setting PERL_ARENA_SIZE appropriately at compile time.
The SV arena serves the secondary purpose of allowing still-live SVs to be located and destroyed during final cleanup.
At the lowest level, the macros new_SV() and del_SV() grab and free an SV head. (If debugging with -DD, del_SV() calls the function S_del_sv() to return the SV to the free list with error checking.) new_SV() calls more_sv() / sv_add_arena() to add an extra arena if the free list is empty. SVs in the free list have their SvTYPE field set to all ones.
At the time of very final cleanup, sv_free_arenas() is called from perl_destruct() to physically free all the arenas allocated since the start of the interpreter.
The function visit() scans the SV arenas list, and calls a specified function for each SV it finds which is still live - ie which has an SvTYPE other than all 1's, and a non-zero SvREFCNT. visit() is used by the following functions (specified as [function that calls visit()] / [function called by visit() for each SV]):
sv_report_used() / do_report_used()dump all remaining SVs (debugging aid) sv_clean_objs() / do_clean_objs(),do_clean_named_objs(), do_clean_named_io_objs(),do_curse()Attempt to free all objects pointed to by RVs,try to do the same for all objects indir-ectly referenced by typeglobs too, andthen do a final sweep, cursing anyobjects that remain. Called once fromperl_destruct(), prior to calling sv_clean_all()below. sv_clean_all() / do_clean_all()SvREFCNT_dec(sv) each remaining SV, possiblytriggering an sv_free(). It also sets theSVf_BREAK flag on the SV to indicate that therefcnt has been artificially lowered, and thusstopping sv_free() from giving spurious warningsabout SVs which unexpectedly have a refcntof zero. called repeatedly from perl_destruct()until there are no SVs left.NOTE: this function is experimental and may change or be removed without notice.
Return an SV with the numeric value of the source SV, doing any necessary reference or overload conversion. The caller is expected to have handled get-magic already.
SV*sv_2num(SV *const sv)Given a chunk of memory, link it to the head of the list of arenas, and split it into a list of free SVs.
voidsv_add_arena(char *const ptr, const U32 size, const U32 flags)Decrement the refcnt of each remaining SV, possibly triggering a cleanup. This function may have to be called multiple times to free SVs which are in complex self-referential hierarchies.
I32sv_clean_all()Attempt to destroy all objects not yet freed.
voidsv_clean_objs()Deallocate the memory used by all arenas. Note that all the individual SV heads and bodies within the arenas must already have been freed.
voidsv_free_arenas()A quick flag check to see whether ansv should be passed tosv_force_normal to be "downgraded" beforeSvIVX orSvPVX can be modified directly.
For example, if your scalar is a reference and you want to modify theSvIVX slot, you can't just doSvROK_off, as that will leak the referent.
This is used internally by various sv-modifying functions, such assv_setsv,sv_setiv andsv_pvn_force.
One case that this does not handle is a gv without SvFAKE set. After
if (SvTHINKFIRST(gv)) sv_force_normal(gv);it will still be a gv.
SvTHINKFIRST sometimes produces false positives. In those casessv_force_normal does nothing.
U32SvTHINKFIRST(SV *sv)NOTE: this function is experimental and may change or be removed without notice.
Find the name of the undefined variable (if any) that caused the operator to issue a "Use of uninitialized value" warning. If match is true, only return a name if its value matchesuninit_sv. So roughly speaking, if a unary operator (such asOP_COS) generates a warning, then following the direct child of the op may yield anOP_PADSV orOP_GV that gives the name of the undefined variable. On the other hand, withOP_ADD there are two branches to follow, so we only print the variable name if we get an exact match.desc_p points to a string pointer holding the description of the op. This may be updated if needed.
The name is returned as a mortal SV.
Assumes thatPL_op is the OP that originally triggered the error, and thatPL_comppad/PL_curpad points to the currently executing pad.
SV*find_uninit_var(const OP *const obase, const SV *const uninit_sv, bool match, const char **desc_p)Returns a bool as to whether or not the sequence of bytes froms up to but not includingsend form a "script run".utf8_target is TRUE iff the sequence starting ats is to be treated as UTF-8. To be precise, except for two degenerate cases given below, this function returns TRUE iff all code points in it come from any combination of three "scripts" given by the Unicode "Script Extensions" property: Common, Inherited, and possibly one other. Additionally all decimal digits must come from the same consecutive sequence of 10.
For example, if all the characters in the sequence are Greek, or Common, or Inherited, this function will return TRUE, provided any decimal digits in it are from the same block of digits in Common. (These are the ASCII digits "0".."9" and additionally a block for full width forms of these, and several others used in mathematical notation.) For scripts (unlike Greek) that have their own digits defined this will accept either digits from that set or from one of the Common digit sets, but not a combination of the two. Some scripts, such as Arabic, have more than one set of digits. All digits must come from the same set for this function to return TRUE.
*ret_script, ifret_script is not NULL, will on return of TRUE contain the script found, using theSCX_enum typedef. Its value will beSCX_INVALID if the function returns FALSE.
If the sequence is empty, TRUE is returned, but*ret_script (if asked for) will beSCX_INVALID.
If the sequence contains a single code point which is unassigned to a character in the version of Unicode being used, the function will return TRUE, and the script will beSCX_Unknown. Any other combination of unassigned code points in the input sequence will result in the function treating the input as not being a script run.
The returned script will beSCX_Inherited iff all the code points in it are from the Inherited script.
Otherwise, the returned script will beSCX_Common iff all the code points in it are from the Inherited or Common scripts.
boolisSCRIPT_RUN(const U8 *s, const U8 *send, const bool utf8_target)Returns TRUE if"is_utf8_invariant_string" in perlapi returns FALSE for the firstlen bytes of the strings, but they are, nonetheless, legal Perl-extended UTF-8; otherwise returns FALSE.
A TRUE return means that at least one code point represented by the sequence either is a wide character not representable as a single byte, or the representation differs depending on whether the sequence is encoded in UTF-8 or not.
See also"is_utf8_invariant_string" in perlapi,"is_utf8_string" in perlapi
boolis_utf8_non_invariant_string(const U8* const s, STRLEN len)Print appropriate "Use of uninitialized variable" warning.
voidreport_uninit(const SV *uninit_sv)This function looks at the sequence of bytes betweens ande, which are assumed to be encoded in ASCII/Latin1, and returns how many of them would change should the string be translated into UTF-8. Due to the nature of UTF-8, each of these would occupy two bytes instead of the single one in the input string. Thus, this function returns the precise number of bytes the string would expand by when translated to UTF-8.
Unlike most of the other functions that haveutf8 in their name, the input to this function is NOT a UTF-8-encoded string. The function name is slightlyodd to emphasize this.
This function is internal to Perl because khw thinks that any XS code that would want this is probably operating too close to the internals. Presenting a valid use case could change that.
See also"is_utf8_invariant_string" in perlapi and"is_utf8_invariant_string_loc" in perlapi,
Size_tvariant_under_utf8_count(const U8* const s, const U8* const e)The following functions are currently undocumented. If you use one of them, you may wish to consider creating and submitting documentation for it.
The autodocumentation system was originally added to the Perl core by Benjamin Stuhl. Documentation is by whoever was kind enough to document their functions.
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