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NAME

       perlintern - autogenerated documentation of purely internal            Perl functions

DESCRIPTION

       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!

Compile-time scope hooks

       BhkENTRY
               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 return NULL.
               The type of the return value depends on which entry you ask for.

               NOTE: this function is experimental and may change or be removed without notice.

                       void *  BhkENTRY(BHK *hk, which)

       BhkFLAGS
               Return the BHK's flags.

               NOTE: this function is experimental and may change or be removed without notice.

                       U32     BhkFLAGS(BHK *hk)

       CALL_BLOCK_HOOKS
               Call all the registered block hooks for type which. which is a preprocessing
               token; the type of arg depends on which.

               NOTE: this function is experimental and may change or be removed without notice.

                       void    CALL_BLOCK_HOOKS(which, arg)

CV reference counts and CvOUTSIDE

       CvWEAKOUTSIDE
               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 by "CvOUTSIDE" in the one specific instance that the
               parent has a "&" pad slot pointing back to us. In this case, we set the
               "CvWEAKOUTSIDE" 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, eg

                   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 has "CvWEAKOUTSIDE" 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 $a is executed, the "eval '$x'" causes the chain of
               "CvOUTSIDE"s 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's "CvOUTSIDE" 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, eg "undef &foo". In this case, its refcount may not have reached zero, but
               we still delete its pad and its "CvROOT" etc.  Since various children may still
               have their "CvOUTSIDE" pointing at this undefined CV, we keep its own "CvOUTSIDE"
               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->();

                       bool    CvWEAKOUTSIDE(CV *cv)

Embedding Functions

       cv_clone
               Clone a CV: make a new CV which points to the same code etc, but which has a
               newly-created pad built by copying the prototype pad and capturing any outer
               lexicals.

                       CV*     cv_clone(CV* proto)

       cv_dump dump the contents of a CV

                       void    cv_dump(const CV *cv, const char *title)

       do_dump_pad
               Dump the contents of a padlist

                       void    do_dump_pad(I32 level, PerlIO *file, PADLIST *padlist, int full)

       intro_my
               "Introduce" my variables to visible status.

                       U32     intro_my()

       pad_add_anon
               Add an anon code entry to the current compiling pad

                       PADOFFSET       pad_add_anon(SV* sv, OPCODE op_type)

       pad_add_name
               Create a new name and associated PADMY SV in the current pad; return the offset.
               If "typestash" is valid, the name is for a typed lexical; set the name's stash to
               that value.  If "ourstash" is valid, it's an our lexical, set the name's
               SvOURSTASH to that value

               If fake, it means we're cloning an existing entry

               NOTE: this function is experimental and may change or be removed without notice.

                       PADOFFSET       pad_add_name(const char *name, const STRLEN len, const U32 flags, HV *typestash, HV *ourstash)

       pad_alloc
               Allocate a new my or tmp pad entry. For a my, simply push a null SV onto the end
               of PL_comppad, but for a tmp, scan the pad from PL_padix upwards for a slot which
               has no name and no active value.

                       PADOFFSET       pad_alloc(I32 optype, U32 tmptype)

       pad_block_start
               Update the pad compilation state variables on entry to a new block

                       void    pad_block_start(int full)

       pad_check_dup
               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

                       void    pad_check_dup(SV *name, const U32 flags, const HV *ourstash)

       pad_findlex
               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 current cop_seq to match against. If
               warn is true, print appropriate warnings.  The out_* 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_sv
               is set to the innermost matched namesv or fake namesv; out_flags returns the flags
               normally associated with the IVX field of a fake namesv.

               Note that pad_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
               namesvs in anon protoypes have to store in xlow the index into the parent pad.

                       PADOFFSET       pad_findlex(const char *name, const CV* cv, U32 seq, int warn, SV** out_capture, SV** out_name_sv, int *out_flags)

       pad_fixup_inner_anons
               For any anon CVs in the pad, change CvOUTSIDE of that CV from old_cv to new_cv if
               necessary. Needed when a newly-compiled CV has to be moved to a pre-existing CV
               struct.

                       void    pad_fixup_inner_anons(PADLIST *padlist, CV *old_cv, CV *new_cv)

       pad_free
               Free the SV at offset po in the current pad.

                       void    pad_free(PADOFFSET po)

       pad_leavemy
               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.

                       void    pad_leavemy()

       pad_push
               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.

                       void    pad_push(PADLIST *padlist, int depth)

       pad_reset
               Mark all the current temporaries for reuse

                       void    pad_reset()

       pad_setsv
               Set the entry at offset po in the current pad to sv.  Use the macro PAD_SETSV()
               rather than calling this function directly.

                       void    pad_setsv(PADOFFSET po, SV* sv)

       pad_swipe
               Abandon the tmp in the current pad at offset po and replace with a new one.

                       void    pad_swipe(PADOFFSET po, bool refadjust)

       pad_tidy
               Tidy up a pad after we've finished compiling it:
                   * remove most stuff from the pads of anonsub prototypes;
                   * give it a @_;
                   * mark tmps as such.

                       void    pad_tidy(padtidy_type type)

Functions in file pad.h

       CX_CURPAD_SAVE
               Save the current pad in the given context block structure.

                       void    CX_CURPAD_SAVE(struct context)

       CX_CURPAD_SV
               Access the SV at offset po 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)

       PAD_BASE_SV
               Get the value from slot "po" in the base (DEPTH=1) pad of a padlist

                       SV *    PAD_BASE_SV(PADLIST padlist, PADOFFSET po)

       PAD_CLONE_VARS
               Clone the state variables associated with running and compiling pads.

                       void    PAD_CLONE_VARS(PerlInterpreter *proto_perl, CLONE_PARAMS* param)

       PAD_COMPNAME_FLAGS
               Return the flags for the current compiling pad name at offset "po". Assumes a
               valid slot entry.

                       U32     PAD_COMPNAME_FLAGS(PADOFFSET po)

       PAD_COMPNAME_GEN
               The generation number of the name at offset "po" in the current compiling pad
               (lvalue). Note that "SvUVX" is hijacked for this purpose.

                       STRLEN  PAD_COMPNAME_GEN(PADOFFSET po)

       PAD_COMPNAME_GEN_set
               Sets the generation number of the name at offset "po" in the current ling pad
               (lvalue) to "gen".  Note that "SvUV_set" is hijacked for this purpose.

                       STRLEN  PAD_COMPNAME_GEN_set(PADOFFSET po, int gen)

       PAD_COMPNAME_OURSTASH
               Return the stash associated with an "our" variable.  Assumes the slot entry is a
               valid "our" lexical.

                       HV *    PAD_COMPNAME_OURSTASH(PADOFFSET po)

       PAD_COMPNAME_PV
               Return the name of the current compiling pad name at offset "po". Assumes a valid
               slot entry.

                       char *  PAD_COMPNAME_PV(PADOFFSET po)

       PAD_COMPNAME_TYPE
               Return the type (stash) of the current compiling pad name at offset "po". Must be
               a valid name. Returns null if not typed.

                       HV *    PAD_COMPNAME_TYPE(PADOFFSET po)

       PAD_DUP Clone a padlist.

                       void    PAD_DUP(PADLIST dstpad, PADLIST srcpad, CLONE_PARAMS* param)

       PAD_RESTORE_LOCAL
               Restore the old pad saved into the local variable opad by PAD_SAVE_LOCAL()

                       void    PAD_RESTORE_LOCAL(PAD *opad)

       PAD_SAVE_LOCAL
               Save the current pad to the local variable opad, then make the current pad equal
               to npad

                       void    PAD_SAVE_LOCAL(PAD *opad, PAD *npad)

       PAD_SAVE_SETNULLPAD
               Save the current pad then set it to null.

                       void    PAD_SAVE_SETNULLPAD()

       PAD_SETSV
               Set the slot at offset "po" in the current pad to "sv"

                       SV *    PAD_SETSV(PADOFFSET po, SV* sv)

       PAD_SET_CUR
               Set the current pad to be pad "n" 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);

                       void    PAD_SET_CUR(PADLIST padlist, I32 n)

       PAD_SET_CUR_NOSAVE
               like PAD_SET_CUR, but without the save

                       void    PAD_SET_CUR_NOSAVE(PADLIST padlist, I32 n)

       PAD_SV  Get the value at offset "po" in the current pad

                       void    PAD_SV(PADOFFSET po)

       PAD_SVl Lightweight and lvalue version of "PAD_SV".  Get or set the value at offset "po"
               in the current pad.  Unlike "PAD_SV", does not print diagnostics with -DX.  For
               internal use only.

                       SV *    PAD_SVl(PADOFFSET po)

       SAVECLEARSV
               Clear the pointed to pad value on scope exit. (i.e. the runtime action of 'my')

                       void    SAVECLEARSV(SV **svp)

       SAVECOMPPAD
               save PL_comppad and PL_curpad

                       void    SAVECOMPPAD()

       SAVEPADSV
               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)

Functions in file pp_ctl.c

       docatch 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

               See cop.h: je_mustcatch, when set at any runlevel to TRUE, means eval ops must
               establish a local jmpenv to handle exception traps.

                       OP*     docatch(OP *o)

GV Functions

       gv_try_downgrade
               If the typeglob "gv" 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 that "gv" 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.

               If "gv" is a completely empty typeglob, it is deleted from the stash.

               If "gv" 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.

               NOTE: this function is experimental and may change or be removed without notice.

                       void    gv_try_downgrade(GV* gv)

       is_gv_magical_sv
               Returns "TRUE" if given the name of a magical GV.

               Currently only useful internally when determining if a GV should be created even
               in rvalue contexts.

               "flags" is not used at present but available for future extension to allow
               selecting particular classes of magical variable.

               Currently assumes that "name" is NUL terminated (as well as len being valid).
               This assumption is met by all callers within the perl core, which all pass
               pointers returned by SvPV.

                       bool    is_gv_magical_sv(SV *const name_sv, U32 flags)

Hash Manipulation Functions

       hv_ename_add
               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.

                       void    hv_ename_add(HV *hv, const char *name, U32 len, U32 flags)

       hv_ename_delete
               Removes a name from a stash's internal list of effective names. If this is the
               name returned by "HvENAME", 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.

                       void    hv_ename_delete(HV *hv, const char *name, U32 len, U32 flags)

       refcounted_he_chain_2hv
               Generates and returns a "HV *" representing the content of a "refcounted_he"
               chain.  flags is currently unused and must be zero.

                       HV *    refcounted_he_chain_2hv(const struct refcounted_he *c, U32 flags)

       refcounted_he_fetch_pv
               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)

       refcounted_he_fetch_pvn
               Search along a "refcounted_he" chain for an entry with the key specified by keypv
               and keylen.  If flags has the "REFCOUNTED_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)

       refcounted_he_fetch_pvs
               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, const char *key, U32 flags)

       refcounted_he_fetch_sv
               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)

       refcounted_he_free
               Decrements the reference count of a "refcounted_he" by one.  If the reference
               count reaches zero the structure's memory is freed, which (recursively) causes a
               reduction of its parent "refcounted_he"'s reference count.  It is safe to pass a
               null pointer to this function: no action occurs in this case.

                       void    refcounted_he_free(struct refcounted_he *he)

       refcounted_he_inc
               Increment the reference count of a "refcounted_he".  The pointer to the
               "refcounted_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)

       refcounted_he_new_pv
               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)

       refcounted_he_new_pvn
               Creates a new "refcounted_he".  This consists of a single key/value pair and a
               reference to an existing "refcounted_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 by keypv and keylen.  If flags has the
               "REFCOUNTED_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 the
               "refcounted_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 the "refcounted_he" chain to be attached to the new
               "refcounted_he".  This function takes ownership of one reference to parent, and
               returns one reference to the new "refcounted_he".

                       struct refcounted_he *  refcounted_he_new_pvn(struct refcounted_he *parent, const char *keypv, STRLEN keylen, U32 hash, SV *value, U32 flags)

       refcounted_he_new_pvs
               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, const char *key, SV *value, U32 flags)

       refcounted_he_new_sv
               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)

IO Functions

       start_glob
               Function called by "do_readline" to spawn a glob (or do the glob inside perl on
               VMS). This code used to be inline, but now perl uses "File::Glob" this glob
               starter is only used by miniperl during the build process.  Moving it away shrinks
               pp_hot.c; shrinking pp_hot.c helps speed perl up.

               NOTE: this function is experimental and may change or be removed without notice.

                       PerlIO* start_glob(SV *tmpglob, IO *io)

Magical Functions

       magic_clearhint
               Triggered by a delete from %^H, records the key to "PL_compiling.cop_hints_hash".

                       int     magic_clearhint(SV* sv, MAGIC* mg)

       magic_clearhints
               Triggered by clearing %^H, resets "PL_compiling.cop_hints_hash".

                       int     magic_clearhints(SV* sv, MAGIC* mg)

       magic_methcall
               Invoke a magic method (like FETCH).

               * sv and mg 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;
                      the args themselves are any values following the argc argument.  * flags:
                   G_DISCARD:     invoke method with G_DISCARD flag and don't return a value
                   G_UNDEF_FILL:  fill the stack with argc pointers to PL_sv_undef.

               Returns the SV (if any) returned by the method, or NULL on failure.

                       SV*     magic_methcall(SV *sv, const MAGIC *mg, const char *meth, U32 flags, U32 argc, ...)

       magic_sethint
               Triggered by a store to %^H, records the key/value pair to
               "PL_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.

                       int     magic_sethint(SV* sv, MAGIC* mg)

       mg_localize
               Copy some of the magic from an existing SV to new localized version of that SV.
               Container magic (eg %ENV, $1, tie) gets copied, value magic doesn't (eg taint,
               pos).

               If setmagic 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.

                       void    mg_localize(SV* sv, SV* nsv, bool setmagic)

MRO Functions

       mro_get_linear_isa_dfs
               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 for "SvREFCNT_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)

       mro_isa_changed_in
               Takes the necessary steps (cache invalidations, mostly) when the @ISA of the given
               package has changed.  Invoked by the "setisa" magic, should not need to invoke
               directly.

                       void    mro_isa_changed_in(HV* stash)

       mro_package_moved
               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 that "oldstash" 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 in "stash".

               It also sets the effective names ("HvENAME") on all the stashes as appropriate.

               If the "gv" is present and is not in the symbol table, then this function simply
               returns. This checked will be skipped if "flags & 1".

                       void    mro_package_moved(HV * const stash, HV * const oldstash, const GV * const gv, U32 flags)

Pad Data Structures

       CvPADLIST
               CV's can have CvPADLIST(cv) set to point to an AV.

               For these purposes "forms" are a kind-of CV, eval""s are too (except they're not
               callable at will and are always thrown away after the eval"" is done executing).
               Require'd files are simply evals without any outer lexical scope.

               XSUBs don't have CvPADLIST set - dXSTARG fetches values from PL_curpad, but that
               is really the callers pad (a slot of which is allocated by every entersub).

               The CvPADLIST AV has does not have AvREAL set, so REFCNT of component items is
               managed "manual" (mostly in pad.c) rather than normal av.c rules.  The items in
               the AV are not SVs as for a normal AV, but other AVs:

               0'th Entry of the CvPADLIST is an AV which represents the "names" or rather the
               "static type information" for lexicals.

               The CvDEPTH'th entry of CvPADLIST AV is an AV which is the stack frame at that
               depth of recursion into the CV.  The 0'th slot of a frame AV is an AV which is @_.
               other entries are storage for variables and op targets.

               During compilation: "PL_comppad_name" is set to the names AV.  "PL_comppad" is set
               to the frame AV for the frame CvDEPTH == 1.  "PL_curpad" is set to the body of the
               frame AV (i.e. AvARRAY(PL_comppad)).

               During execution, "PL_comppad" and "PL_curpad" refer to the live frame of the
               currently executing sub.

               Iterating over the names AV iterates over all possible pad items. Pad slots that
               are SVs_PADTMP (targets/GVs/constants) end up having &PL_sv_undef "names" (see
               pad_alloc()).

               Only my/our variable (SVs_PADMY/SVs_PADOUR) slots get valid names.  The rest are
               op targets/GVs/constants which are statically allocated or resolved at compile
               time.  These don't have names by which they can be looked up from Perl code at run
               time through eval"" like my/our variables can be.  Since they can't be looked up
               by "name" but only by their index allocated at compile time (which is usually in
               PL_op->op_targ), wasting a name SV for them doesn't make sense.

               The SVs in the names AV have their PV being the name of the variable.
               xlow+1..xhigh inclusive in the NV union is a range of cop_seq numbers for which
               the name is valid (accessed through the macros COP_SEQ_RANGE_LOW and _HIGH).
               During compilation, these fields may hold the special value PERL_PADSEQ_INTRO to
               indicate various stages:

                  COP_SEQ_RANGE_LOW        _HIGH
                  -----------------        -----
                  PERL_PADSEQ_INTRO            0   variable not yet introduced:   { my ($x
                  valid-seq#   PERL_PADSEQ_INTRO   variable in scope:             { my ($x)
                  valid-seq#          valid-seq#   compilation of scope complete: { my ($x) }

               For typed lexicals name SV is SVt_PVMG and SvSTASH points at the type.  For "our"
               lexicals, the type is also SVt_PVMG, with the SvOURSTASH slot pointing at the
               stash of the associated global (so that duplicate "our" declarations in the same
               package can be detected).  SvUVX is sometimes hijacked to store the generation
               number during compilation.

               If SvFAKE is set on the name SV, then that slot in the frame AV is a REFCNT'ed
               reference to a lexical from "outside". In this case, the name SV does not use xlow
               and xhigh to store a cop_seq range, since it is in scope throughout. Instead xhigh
               stores some flags containing info about the real lexical (is it declared in an
               anon, and is it capable of being instantiated multiple times?), and for fake
               ANONs, xlow contains the index within the parent's pad where the lexical's value
               is stored, to make cloning quicker.

               If the 'name' is '&' the corresponding entry in frame AV is a CV representing a
               possible closure.  (SvFAKE and name of '&' is not a meaningful combination
               currently but could become so if "my sub foo {}" is implemented.)

               Note that formats are treated as anon subs, and are cloned each time write is
               called (if necessary).

               The flag SVs_PADSTALE is cleared on lexicals each time the my() is executed, and
               set on scope exit. This allows the 'Variable $x is not available' warning to be
               generated in evals, such as

                   { my $x = 1; sub f { eval '$x'} } f();

               For state vars, SVs_PADSTALE is overloaded to mean 'not yet initialised'

                       AV *    CvPADLIST(CV *cv)

       pad_new Create a new compiling padlist, saving and updating the various global vars at the
               same time as creating the pad itself. The following flags can be OR'ed together:

                   padnew_CLONE        this pad is for a cloned CV
                   padnew_SAVE         save old globals
                   padnew_SAVESUB      also save extra stuff for start of sub

                       PADLIST*        pad_new(int flags)

Per-Interpreter Variables

       PL_DBsingle
               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_DBsingle

       PL_DBsub
               When 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_DBsub

       PL_DBtrace
               Trace 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_DBtrace

       PL_dowarn
               The C variable which corresponds to Perl's $^W warning variable.

                       bool    PL_dowarn

       PL_last_in_gv
               The GV which was last used for a filehandle input operation. ("<FH>")

                       GV*     PL_last_in_gv

       PL_ofsgv
               The glob containing the output field separator - "*," in Perl space.

                       GV*     PL_ofsgv

       PL_rs   The input record separator - $/ in Perl space.

                       SV*     PL_rs

Stack Manipulation Macros

       djSP    Declare Just "SP". This is actually identical to "dSP", and declares a local copy
               of perl's stack pointer, available via the "SP" macro.  See "SP".  (Available for
               backward source code compatibility with the old (Perl 5.005) thread model.)

                               djSP;

       LVRET   True if this op will be the return value of an lvalue subroutine

SV Manipulation Functions

       sv_add_arena
               Given a chunk of memory, link it to the head of the list of arenas, and split it
               into a list of free SVs.

                       void    sv_add_arena(char *const ptr, const U32 size, const U32 flags)

       sv_clean_all
               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.

                       I32     sv_clean_all()

       sv_clean_objs
               Attempt to destroy all objects not yet freed

                       void    sv_clean_objs()

       sv_free_arenas
               Deallocate the memory used by all arenas. Note that all the individual SV heads
               and bodies within the arenas must already have been freed.

                       void    sv_free_arenas()

SV-Body Allocation

       sv_2num Return an SV with the numeric value of the source SV, doing any necessary
               reference or overload conversion.  You must use the "SvNUM(sv)" macro to access
               this function.

               NOTE: this function is experimental and may change or be removed without notice.

                       SV*     sv_2num(SV *const sv)

Unicode Support

       find_uninit_var
               Find the name of the undefined variable (if any) that caused the operator o to
               issue a "Use of uninitialized value" warning.  If match is true, only return a
               name if it's value matches uninit_sv.  So roughly speaking, if a unary operator
               (such as OP_COS) generates a warning, then following the direct child of the op
               may yield an OP_PADSV or OP_GV that gives the name of the undefined variable. On
               the other hand, with OP_ADD there are two branches to follow, so we only print the
               variable name if we get an exact match.

               The name is returned as a mortal SV.

               Assumes that PL_op is the op that originally triggered the error, and that
               PL_comppad/PL_curpad points to the currently executing pad.

               NOTE: this function is experimental and may change or be removed without notice.

                       SV*     find_uninit_var(const OP *const obase, const SV *const uninit_sv, bool top)

       report_uninit
               Print appropriate "Use of uninitialized variable" warning

                       void    report_uninit(const SV *uninit_sv)

Undocumented functions

       The following functions have been flagged as part of the public API, but are currently
       undocumented. Use them at your own risk, as the interfaces are subject to change.

       If you use one of them, you may wish to consider creating and submitting documentation for
       it. If your patch is accepted, this will indicate that the interface is stable (unless it
       is explicitly marked otherwise).

       F0convert
       Slab_to_rw
       _append_range_to_invlist
       _new_invlist
       _swash_inversion_hash
       _swash_to_invlist
       add_alternate
       add_cp_to_invlist
       add_data
       add_range_to_invlist
       add_utf16_textfilter
       addmad
       allocmy
       amagic_cmp
       amagic_cmp_locale
       amagic_i_ncmp
       amagic_ncmp
       anonymise_cv_maybe
       ao
       append_madprops
       apply
       apply_attrs
       apply_attrs_my
       assert_uft8_cache_coherent
       av_reify
       bad_type
       bind_match
       block_end
       block_start
       boot_core_PerlIO
       boot_core_UNIVERSAL
       boot_core_mro
       bytes_to_uni
       cando
       check_type_and_open
       check_uni
       check_utf8_print
       checkcomma
       checkposixcc
       ckwarn_common
       cl_and
       cl_anything
       cl_init
       cl_is_anything
       cl_or
       clear_placeholders
       closest_cop
       convert
       cop_free
       cr_textfilter
       create_eval_scope
       curmad
       curse
       cv_ckproto_len
       cvgv_set
       cvstash_set
       deb_curcv
       deb_stack_all
       deb_stack_n
       debprof
       debug_start_match
       del_sv
       delete_eval_scope
       deprecate_commaless_var_list
       destroy_matcher
       die_unwind
       div128
       do_aexec
       do_aexec5
       do_chomp
       do_delete_local
       do_eof
       do_exec
       do_exec3
       do_execfree
       do_ipcctl
       do_ipcget
       do_msgrcv
       do_msgsnd
       do_oddball
       do_op_xmldump
       do_pmop_xmldump
       do_print
       do_readline
       do_seek
       do_semop
       do_shmio
       do_smartmatch
       do_sysseek
       do_tell
       do_trans
       do_trans_complex
       do_trans_complex_utf8
       do_trans_count
       do_trans_count_utf8
       do_trans_simple
       do_trans_simple_utf8
       do_vecget
       do_vecset
       do_vop
       doeval
       dofile
       dofindlabel
       doform
       dooneliner
       doopen_pm
       doparseform
       dopoptoeval
       dopoptogiven
       dopoptolabel
       dopoptoloop
       dopoptosub_at
       dopoptowhen
       dump_all_perl
       dump_exec_pos
       dump_packsubs_perl
       dump_sub_perl
       dump_sv_child
       dump_trie
       dump_trie_interim_list
       dump_trie_interim_table
       dumpuntil
       dup_attrlist
       emulate_cop_io
       exec_failed
       expect_number
       feature_is_enabled
       filter_gets
       find_and_forget_pmops
       find_array_subscript
       find_beginning
       find_byclass
       find_hash_subscript
       find_in_my_stash
       find_script
       first_symbol
       fold_constants
       forbid_setid
       force_ident
       force_list
       force_next
       force_strict_version
       force_version
       force_word
       forget_pmop
       free_tied_hv_pool
       gen_constant_list
       get_aux_mg
       get_db_sub
       get_debug_opts
       get_hash_seed
       get_no_modify
       get_num
       get_opargs
       get_re_arg
       getenv_len
       glob_2number
       glob_assign_glob
       glob_assign_ref
       grok_bslash_c
       grok_bslash_o
       group_end
       gv_ename
       gv_get_super_pkg
       gv_init_sv
       gv_magicalize_isa
       gv_magicalize_overload
       hfreeentries
       hsplit
       hv_auxinit
       hv_backreferences_p
       hv_delete_common
       hv_kill_backrefs
       hv_magic_check
       hv_notallowed
       hv_undef_flags
       incline
       incpush
       incpush_if_exists
       incpush_use_sep
       ingroup
       init_argv_symbols
       init_dbargs
       init_debugger
       init_ids
       init_interp
       init_main_stash
       init_perllib
       init_postdump_symbols
       init_predump_symbols
       intuit_method
       intuit_more
       invert
       invlist_array
       invlist_destroy
       invlist_extend
       invlist_intersection
       invlist_len
       invlist_max
       invlist_set_len
       invlist_set_max
       invlist_trim
       invlist_union
       invoke_exception_hook
       io_close
       is_an_int
       is_handle_constructor
       is_inplace_av
       is_list_assignment
       is_utf8_X_L
       is_utf8_X_LV
       is_utf8_X_LVT
       is_utf8_X_LV_LVT_V
       is_utf8_X_T
       is_utf8_X_V
       is_utf8_X_begin
       is_utf8_X_extend
       is_utf8_X_non_hangul
       is_utf8_X_prepend
       is_utf8_char_slow
       is_utf8_common
       isa_lookup
       jmaybe
       join_exact
       keyword
       keyword_plugin_standard
       list
       listkids
       localize
       looks_like_bool
       lop
       mad_free
       madlex
       madparse
       magic_clear_all_env
       magic_clearenv
       magic_clearisa
       magic_clearpack
       magic_clearsig
       magic_existspack
       magic_freearylen_p
       magic_freeovrld
       magic_get
       magic_getarylen
       magic_getdefelem
       magic_getnkeys
       magic_getpack
       magic_getpos
       magic_getsig
       magic_getsubstr
       magic_gettaint
       magic_getuvar
       magic_getvec
       magic_killbackrefs
       magic_len
       magic_methcall1
       magic_methpack
       magic_nextpack
       magic_regdata_cnt
       magic_regdatum_get
       magic_regdatum_set
       magic_scalarpack
       magic_set
       magic_set_all_env
       magic_setamagic
       magic_setarylen
       magic_setcollxfrm
       magic_setdbline
       magic_setdefelem
       magic_setenv
       magic_setisa
       magic_setmglob
       magic_setnkeys
       magic_setpack
       magic_setpos
       magic_setregexp
       magic_setsig
       magic_setsubstr
       magic_settaint
       magic_setutf8
       magic_setuvar
       magic_setvec
       magic_sizepack
       magic_wipepack
       make_matcher
       make_trie
       make_trie_failtable
       malloc_good_size
       malloced_size
       matcher_matches_sv
       measure_struct
       mem_collxfrm
       mem_log_common
       mess_alloc
       method_common
       missingterm
       mod
       mode_from_discipline
       modkids
       more_bodies
       more_sv
       mro_clean_isarev
       mro_gather_and_rename
       mro_meta_dup
       mro_meta_init
       mul128
       mulexp10
       munge_qwlist_to_paren_list
       my_attrs
       my_betoh16
       my_betoh32
       my_betoh64
       my_betohi
       my_betohl
       my_betohs
       my_clearenv
       my_exit_jump
       my_htobe16
       my_htobe32
       my_htobe64
       my_htobei
       my_htobel
       my_htobes
       my_htole16
       my_htole32
       my_htole64
       my_htolei
       my_htolel
       my_htoles
       my_kid
       my_letoh16
       my_letoh32
       my_letoh64
       my_letohi
       my_letohl
       my_letohs
       my_lstat_flags
       my_stat_flags
       my_swabn
       my_unexec
       need_utf8
       newDEFSVOP
       newGIVWHENOP
       newGP
       newMADPROP
       newMADsv
       newTOKEN
       new_constant
       new_he
       new_logop
       new_warnings_bitfield
       next_symbol
       nextargv
       nextchar
       no_bareword_allowed
       no_fh_allowed
       no_op
       not_a_number
       nuke_stacks
       num_overflow
       oopsAV
       oopsHV
       op_clear
       op_const_sv
       op_getmad
       op_getmad_weak
       op_refcnt_dec
       op_refcnt_inc
       op_xmldump
       open_script
       opt_scalarhv
       pack_rec
       package
       package_version
       pad_add_name_sv
       pad_compname_type
       pad_peg
       padlist_dup
       parse_body
       parse_unicode_opts
       parser_free
       path_is_absolute
       peep
       pending_Slabs_to_ro
       pidgone
       pm_description
       pmop_xmldump
       pmruntime
       pmtrans
       populate_isa
       prepend_madprops
       printbuf
       process_special_blocks
       ptr_table_find
       put_byte
       qerror
       qsortsvu
       re_croak2
       readpipe_override
       ref_array_or_hash
       refcounted_he_value
       refkids
       refto
       reg
       reg_check_named_buff_matched
       reg_named_buff
       reg_named_buff_iter
       reg_namedseq
       reg_node
       reg_numbered_buff_fetch
       reg_numbered_buff_length
       reg_numbered_buff_store
       reg_qr_package
       reg_recode
       reg_scan_name
       reg_skipcomment
       reg_temp_copy
       reganode
       regatom
       regbranch
       regclass
       regcppop
       regcppush
       regcurly
       regdump_extflags
       reghop3
       reghop4
       reghopmaybe3
       reginclass
       reginsert
       regmatch
       regpiece
       regpposixcc
       regprop
       regrepeat
       regtail
       regtail_study
       regtry
       reguni
       regwhite
       report_evil_fh
       report_wrongway_fh
       require_tie_mod
       restore_magic
       rpeep
       rsignal_restore
       rsignal_save
       run_body
       run_user_filter
       rxres_free
       rxres_restore
       rxres_save
       same_dirent
       save_hek_flags
       save_lines
       save_magic
       save_pushptri32ptr
       save_scalar_at
       sawparens
       scalar
       scalar_mod_type
       scalarboolean
       scalarkids
       scalarseq
       scalarvoid
       scan_commit
       scan_const
       scan_formline
       scan_heredoc
       scan_ident
       scan_inputsymbol
       scan_pat
       scan_str
       scan_subst
       scan_trans
       scan_word
       search_const
       sequence
       sequence_num
       sequence_tail
       set_regclass_bit
       set_regclass_bit_fold
       share_hek_flags
       sighandler
       simplify_sort
       skipspace
       skipspace0
       skipspace1
       skipspace2
       softref2xv
       sortcv
       sortcv_stacked
       sortcv_xsub
       space_join_names_mortal
       start_force
       stdize_locale
       store_cop_label
       strip_return
       study_chunk
       sub_crush_depth
       sublex_done
       sublex_push
       sublex_start
       sv_2iuv_common
       sv_2iuv_non_preserve
       sv_add_backref
       sv_catxmlpv
       sv_catxmlpvn
       sv_catxmlsv
       sv_compile_2op_is_broken
       sv_del_backref
       sv_dup_common
       sv_dup_inc_multiple
       sv_exp_grow
       sv_free2
       sv_i_ncmp
       sv_kill_backrefs
       sv_ncmp
       sv_pos_b2u_midway
       sv_pos_u2b_cached
       sv_pos_u2b_forwards
       sv_pos_u2b_midway
       sv_release_COW
       sv_setsv_cow
       sv_unglob
       sv_xmlpeek
       swallow_bom
       swash_get
       tied_method
       to_byte_substr
       to_utf8_substr
       token_free
       token_getmad
       tokenize_use
       tokeq
       tokereport
       too_few_arguments
       too_many_arguments
       try_amagic_bin
       try_amagic_un
       uiv_2buf
       unpack_rec
       unreferenced_to_tmp_stack
       unshare_hek
       unshare_hek_or_pvn
       unwind_handler_stack
       update_debugger_info
       usage
       utf16_textfilter
       utf8_mg_len_cache_update
       utf8_mg_pos_cache_update
       utilize
       validate_suid
       varname
       visit
       vivify_defelem
       vivify_ref
       wait4pid
       watch
       with_queued_errors
       write_no_mem
       write_to_stderr
       xmldump_all
       xmldump_all_perl
       xmldump_attr
       xmldump_eval
       xmldump_form
       xmldump_indent
       xmldump_packsubs
       xmldump_packsubs_perl
       xmldump_sub
       xmldump_sub_perl
       xmldump_vindent
       xs_apiversion_bootcheck
       xs_version_bootcheck
       yyerror
       yylex
       yyparse
       yyunlex
       yywarn

AUTHORS

       The autodocumentation system was originally added to the Perl core by Benjamin Stuhl.
       Documentation is by whoever was kind enough to document their functions.

SEE ALSO

       perlguts, perlapi