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perlapi




DESCRIPTION

       This file contains the documentation of the perl public
       API generated by embed.pl, specifically a listing of func­
       tions, macros, flags, and variables that may be used by
       extension writers.  The interfaces of any functions that
       are not listed here are subject to change without notice.
       For this reason, blindly using functions listed in proto.h
       is to be avoided when writing extensions.

       Note that all Perl API global variables must be referenced
       with the "PL_" prefix.  Some macros are provided for com­
       patibility with the older, unadorned names, but this sup­
       port may be disabled in a future release.

       The listing is alphabetical, case insensitive.


"Gimme" Values

       GIMME   A backward-compatible version of "GIMME_V" which
               can only return "G_SCALAR" or "G_ARRAY"; in a void
               context, it returns "G_SCALAR".  Deprecated.  Use
               "GIMME_V" instead.

                       U32     GIMME

       GIMME_V The XSUB-writer's equivalent to Perl's "wantar­
               ray".  Returns "G_VOID", "G_SCALAR" or "G_ARRAY"
               for void, scalar or list context, respectively.

                       U32     GIMME_V

       G_ARRAY Used to indicate list context.  See "GIMME_V",
               "GIMME" and perlcall.

       G_DISCARD
               Indicates that arguments returned from a callback
               should be discarded.  See perlcall.

       G_EVAL  Used to force a Perl "eval" wrapper around a call­
               back.  See perlcall.

       G_NOARGS
               Indicates that no arguments are being sent to a
               callback.  See perlcall.

       G_SCALAR
               Used to indicate scalar context.  See "GIMME_V",
               "GIMME", and perlcall.

       G_VOID  Used to indicate void context.  See "GIMME_V" and
               perlcall.

               array.  Returns the deleted element. "flags" is
               currently ignored.

                       SV*     av_delete(AV* ar, I32 key, I32 flags)

       av_exists
               Returns true if the element indexed by "key" has
               been initialized.

               This relies on the fact that uninitialized array
               elements are set to &PL_sv_undef.

                       bool    av_exists(AV* ar, I32 key)

       av_extend
               Pre-extend an array.  The "key" is the index to
               which the array should be extended.

                       void    av_extend(AV* ar, I32 key)

       av_fetch
               Returns the SV at the specified index in the
               array.  The "key" is the index.  If "lval" is set
               then the fetch will be part of a store.  Check
               that the return value is non-null before derefer­
               encing it to a "SV*".

               See "Understanding the Magic of Tied Hashes and
               Arrays" in perlguts for more information on how to
               use this function on tied arrays.

                       SV**    av_fetch(AV* ar, I32 key, I32 lval)

       av_fill Ensure than an array has a given number of ele­
               ments, equivalent to Perl's "$#array = $fill;".

                       void    av_fill(AV* ar, I32 fill)

       av_len  Returns the highest index in the array.  Returns
               -1 if the array is empty.

                       I32     av_len(AV* ar)

       av_make Creates a new AV and populates it with a list of
               SVs.  The SVs are copied into the array, so they
               may be freed after the call to av_make.  The new
               AV will have a reference count of 1.

                       AV*     av_make(I32 size, SV** svp)

       av_pop  Pops an SV off the end of the array.  Returns
               &PL_sv_undef if the array is empty.

       av_store
               Stores an SV in an array.  The array index is
               specified as "key".  The return value will be NULL
               if the operation failed or if the value did not
               need to be actually stored within the array (as in
               the case of tied arrays). Otherwise it can be
               dereferenced to get the original "SV*".  Note that
               the caller is responsible for suitably increment­
               ing the reference count of "val" before the call,
               and decrementing it if the function returned NULL.

               See "Understanding the Magic of Tied Hashes and
               Arrays" in perlguts for more information on how to
               use this function on tied arrays.

                       SV**    av_store(AV* ar, I32 key, SV* val)

       av_undef
               Undefines the array.  Frees the memory used by the
               array itself.

                       void    av_undef(AV* ar)

       av_unshift
               Unshift the given number of "undef" values onto
               the beginning of the array.  The array will grow
               automatically to accommodate the addition.  You
               must then use "av_store" to assign values to these
               new elements.

                       void    av_unshift(AV* ar, I32 num)

       get_av  Returns the AV of the specified Perl array.  If
               "create" is set and the Perl variable does not
               exist then it will be created.  If "create" is not
               set and the variable does not exist then NULL is
               returned.

               NOTE: the perl_ form of this function is depre­
               cated.

                       AV*     get_av(const char* name, I32 create)

       newAV   Creates a new AV.  The reference count is set to
               1.

                       AV*     newAV()

       Nullav  Null AV pointer.

       sortsv  Sort an array. Here is an example:


                       I32     call_argv(const char* sub_name, I32 flags, char** argv)

       call_method
               Performs a callback to the specified Perl method.
               The blessed object must be on the stack.  See
               perlcall.

               NOTE: the perl_ form of this function is depre­
               cated.

                       I32     call_method(const char* methname, I32 flags)

       call_pv Performs a callback to the specified Perl sub.
               See perlcall.

               NOTE: the perl_ form of this function is depre­
               cated.

                       I32     call_pv(const char* sub_name, I32 flags)

       call_sv Performs a callback to the Perl sub whose name is
               in the SV.  See perlcall.

               NOTE: the perl_ form of this function is depre­
               cated.

                       I32     call_sv(SV* sv, I32 flags)

       ENTER   Opening bracket on a callback.  See "LEAVE" and
               perlcall.

                               ENTER;

       eval_pv Tells Perl to "eval" the given string and return
               an SV* result.

               NOTE: the perl_ form of this function is depre­
               cated.

                       SV*     eval_pv(const char* p, I32 croak_on_error)

       eval_sv Tells Perl to "eval" the string in the SV.

               NOTE: the perl_ form of this function is depre­
               cated.

                       I32     eval_sv(SV* sv, I32 flags)

       FREETMPS
               Closing bracket for temporaries on a callback.
               See "SAVETMPS" and perlcall.


Character classes

       isALNUM Returns a boolean indicating whether the C "char"
               is an ASCII alphanumeric character (including
               underscore) or digit.

                       bool    isALNUM(char ch)

       isALPHA Returns a boolean indicating whether the C "char"
               is an ASCII alphabetic character.

                       bool    isALPHA(char ch)

       isDIGIT Returns a boolean indicating whether the C "char"
               is an ASCII digit.

                       bool    isDIGIT(char ch)

       isLOWER Returns a boolean indicating whether the C "char"
               is a lowercase character.

                       bool    isLOWER(char ch)

       isSPACE Returns a boolean indicating whether the C "char"
               is whitespace.

                       bool    isSPACE(char ch)

       isUPPER Returns a boolean indicating whether the C "char"
               is an uppercase character.

                       bool    isUPPER(char ch)

       toLOWER Converts the specified character to lowercase.

                       char    toLOWER(char ch)

       toUPPER Converts the specified character to uppercase.

                       char    toUPPER(char ch)


Cloning an interpreter

       perl_clone
               Create and return a new interpreter by cloning the
               current one.

               perl_clone takes these flags as parameters:

               CLONEf_COPY_STACKS - is used to, well, copy the
               stacks also, without it we only clone the data and
               zero the stacks, with it we copy the stacks and
               the new perl interpreter is ready to run at the
               exact same point as the previous one.  The pseudo-
               code is in threads.xs create

               CLONEf_CLONE_HOST This is a win32 thing, it is
               ignored on unix, it tells perls win32host code
               (which is c++) to clone itself, this is needed on
               win32 if you want to run two threads at the same
               time, if you just want to do some stuff in a sepa­
               rate perl interpreter and then throw it away and
               return to the original one, you don't need to do
               anything.

                       PerlInterpreter*        perl_clone(PerlInterpreter* interp, UV flags)


CV Manipulation Functions

       CvSTASH Returns the stash of the CV.

                       HV*     CvSTASH(CV* cv)

       get_cv  Returns the CV of the specified Perl subroutine.
               If "create" is set and the Perl subroutine does
               not exist then it will be declared (which has the
               same effect as saying "sub name;").  If "create"
               is not set and the subroutine does not exist then
               NULL is returned.

               NOTE: the perl_ form of this function is depre­
               cated.

                       CV*     get_cv(const char* name, I32 create)

       Nullcv  Null CV pointer.


Embedding Functions

       cv_undef
               Clear out all the active components of a CV. This
               can happen either by an explicit "undef &foo", or
               by the reference count going to zero.  In the for­
               mer case, we keep the CvOUTSIDE pointer, so that
               any anonymous children can still follow the full
               lexical scope chain.

                       void    cv_undef(CV* cv)

       load_module
               Loads the module whose name is pointed to by the
               string part of name.  Note that the actual module
               name, not its filename, should be given.  Eg,
               "Foo::Bar" instead of "Foo/Bar.pm".  flags can be
               any of PERL_LOADMOD_DENY, PERL_LOADMOD_NOIMPORT,
               or PERL_LOADMOD_IMPORT_OPS (or 0 for no flags).
               ver, if specified, provides version semantics sim­
               ilar to "use Foo::Bar VERSION".  The optional

                       PerlInterpreter*        perl_alloc()

       perl_construct
               Initializes a new Perl interpreter.  See perlem­
               bed.

                       void    perl_construct(PerlInterpreter* interp)

       perl_destruct
               Shuts down a Perl interpreter.  See perlembed.

                       int     perl_destruct(PerlInterpreter* interp)

       perl_free
               Releases a Perl interpreter.  See perlembed.

                       void    perl_free(PerlInterpreter* interp)

       perl_parse
               Tells a Perl interpreter to parse a Perl script.
               See perlembed.

                       int     perl_parse(PerlInterpreter* interp, XSINIT_t xsinit, int argc, char** argv, char** env)

       perl_run
               Tells a Perl interpreter to run.  See perlembed.

                       int     perl_run(PerlInterpreter* interp)

       require_pv
               Tells Perl to "require" the file named by the
               string argument.  It is analogous to the Perl code
               "eval "require '$file'"".  It's even implemented
               that way; consider using load_module instead.

               NOTE: the perl_ form of this function is depre­
               cated.

                       void    require_pv(const char* pv)


Functions in file pp_pack.c

       packlist
               The engine implementing pack() Perl function.

                       void    packlist(SV *cat, char *pat, char *patend, SV **beglist, SV **endlist)

       pack_cat
               The engine implementing pack() Perl function.
               Note: parameters next_in_list and flags are not
               used. This call should not be used; use packlist
               instead.
                       I32     unpack_str(char *pat, char *patend, char *s, char *strbeg, char *strend, char **new_s, I32 ocnt, U32 flags)


Global Variables

       PL_modglobal
               "PL_modglobal" is a general purpose, interpreter
               global HV for use by extensions that need to keep
               information on a per-interpreter basis.  In a
               pinch, it can also be used as a symbol table for
               extensions to share data among each other.  It is
               a good idea to use keys prefixed by the package
               name of the extension that owns the data.

                       HV*     PL_modglobal

       PL_na   A convenience variable which is typically used
               with "SvPV" when one doesn't care about the length
               of the string.  It is usually more efficient to
               either declare a local variable and use that
               instead or to use the "SvPV_nolen" macro.

                       STRLEN  PL_na

       PL_sv_no
               This is the "false" SV.  See "PL_sv_yes".  Always
               refer to this as &PL_sv_no.

                       SV      PL_sv_no

       PL_sv_undef
               This is the "undef" SV.  Always refer to this as
               &PL_sv_undef.

                       SV      PL_sv_undef

       PL_sv_yes
               This is the "true" SV.  See "PL_sv_no".  Always
               refer to this as &PL_sv_yes.

                       SV      PL_sv_yes


GV Functions

       GvSV    Return the SV from the GV.

                       SV*     GvSV(GV* gv)

       gv_fetchmeth
               Returns the glob with the given "name" and a
               defined subroutine or "NULL".  The glob lives in
               the given "stash", or in the stashes accessible
               via @ISA and UNIVERSAL::.

               The argument "level" should be either 0 or -1.  If
                       GV*     gv_fetchmeth(HV* stash, const char* name, STRLEN len, I32 level)

       gv_fetchmethod
               See gv_fetchmethod_autoload.

                       GV*     gv_fetchmethod(HV* stash, const char* name)

       gv_fetchmethod_autoload
               Returns the glob which contains the subroutine to
               call to invoke the method on the "stash".  In fact
               in the presence of autoloading this may be the
               glob for "AUTOLOAD".  In this case the correspond­
               ing variable $AUTOLOAD is already setup.

               The third parameter of "gv_fetchmethod_autoload"
               determines whether AUTOLOAD lookup is performed if
               the given method is not present: non-zero means
               yes, look for AUTOLOAD; zero means no, don't look
               for AUTOLOAD.  Calling "gv_fetchmethod" is equiva­
               lent to calling "gv_fetchmethod_autoload" with a
               non-zero "autoload" parameter.

               These functions grant "SUPER" token as a prefix of
               the method name. Note that if you want to keep the
               returned glob for a long time, you need to check
               for it being "AUTOLOAD", since at the later time
               the call may load a different subroutine due to
               $AUTOLOAD changing its value. Use the glob created
               via a side effect to do this.

               These functions have the same side-effects and as
               "gv_fetchmeth" with "level==0".  "name" should be
               writable if contains ':' or "' ''". The warning
               against passing the GV returned by "gv_fetchmeth"
               to "call_sv" apply equally to these functions.

                       GV*     gv_fetchmethod_autoload(HV* stash, const char* name, I32 autoload)

       gv_fetchmeth_autoload
               Same as gv_fetchmeth(), but looks for autoloaded
               subroutines too.  Returns a glob for the subrou­
               tine.

               For an autoloaded subroutine without a GV, will
               create a GV even if "level < 0".  For an
               autoloaded subroutine without a stub, GvCV() of
               the result may be zero.

                       GV*     gv_fetchmeth_autoload(HV* stash, const char* name, STRLEN len, I32 level)

       gv_stashpv
               Returns a pointer to the stash for a specified


Handy Values

       HEf_SVKEY
               This flag, used in the length slot of hash entries
               and magic structures, specifies the structure con­
               tains an "SV*" pointer where a "char*" pointer is
               to be expected. (For information only--not to be
               used).

       Nullch  Null character pointer.

       Nullsv  Null SV pointer.


Hash Manipulation Functions

       get_hv  Returns the HV of the specified Perl hash.  If
               "create" is set and the Perl variable does not
               exist then it will be created.  If "create" is not
               set and the variable does not exist then NULL is
               returned.

               NOTE: the perl_ form of this function is depre­
               cated.

                       HV*     get_hv(const char* name, I32 create)

       HeHASH  Returns the computed hash stored in the hash
               entry.

                       U32     HeHASH(HE* he)

       HeKEY   Returns the actual pointer stored in the key slot
               of the hash entry. The pointer may be either
               "char*" or "SV*", depending on the value of
               "HeKLEN()".  Can be assigned to.  The "HePV()" or
               "HeSVKEY()" macros are usually preferable for
               finding the value of a key.

                       void*   HeKEY(HE* he)

       HeKLEN  If this is negative, and amounts to "HEf_SVKEY",
               it indicates the entry holds an "SV*" key.  Other­
               wise, holds the actual length of the key.  Can be
               assigned to. The "HePV()" macro is usually prefer­
               able for finding key lengths.

                       STRLEN  HeKLEN(HE* he)

       HePV    Returns the key slot of the hash entry as a
               "char*" value, doing any necessary dereferencing
               of possibly "SV*" keys.  The length of the string
               is placed in "len" (this is a macro, so do not use
               &len).  If you do not care about what the length
                       SV*     HeSVKEY(HE* he)

       HeSVKEY_force
               Returns the key as an "SV*".  Will create and
               return a temporary mortal "SV*" if the hash entry
               contains only a "char*" key.

                       SV*     HeSVKEY_force(HE* he)

       HeSVKEY_set
               Sets the key to a given "SV*", taking care to set
               the appropriate flags to indicate the presence of
               an "SV*" key, and returns the same "SV*".

                       SV*     HeSVKEY_set(HE* he, SV* sv)

       HeVAL   Returns the value slot (type "SV*") stored in the
               hash entry.

                       SV*     HeVAL(HE* he)

       HvNAME  Returns the package name of a stash.  See "SvS­
               TASH", "CvSTASH".

                       char*   HvNAME(HV* stash)

       hv_clear
               Clears a hash, making it empty.

                       void    hv_clear(HV* tb)

       hv_delete
               Deletes a key/value pair in the hash.  The value
               SV is removed from the hash and returned to the
               caller.  The "klen" is the length of the key.  The
               "flags" value will normally be zero; if set to
               G_DISCARD then NULL will be returned.

                       SV*     hv_delete(HV* tb, const char* key, I32 klen, I32 flags)

       hv_delete_ent
               Deletes a key/value pair in the hash.  The value
               SV is removed from the hash and returned to the
               caller.  The "flags" value will normally be zero;
               if set to G_DISCARD then NULL will be returned.
               "hash" can be a valid precomputed hash value, or 0
               to ask for it to be computed.

                       SV*     hv_delete_ent(HV* tb, SV* key, I32 flags, U32 hash)

       hv_exists
               Returns a boolean indicating whether the specified
               key in the hash.  The "klen" is the length of the
               key.  If "lval" is set then the fetch will be part
               of a store.  Check that the return value is non-
               null before dereferencing it to an "SV*".

               See "Understanding the Magic of Tied Hashes and
               Arrays" in perlguts for more information on how to
               use this function on tied hashes.

                       SV**    hv_fetch(HV* tb, const char* key, I32 klen, I32 lval)

       hv_fetch_ent
               Returns the hash entry which corresponds to the
               specified key in the hash.  "hash" must be a valid
               precomputed hash number for the given "key", or 0
               if you want the function to compute it.  IF "lval"
               is set then the fetch will be part of a store.
               Make sure the return value is non-null before
               accessing it.  The return value when "tb" is a
               tied hash is a pointer to a static location, so be
               sure to make a copy of the structure if you need
               to store it somewhere.

               See "Understanding the Magic of Tied Hashes and
               Arrays" in perlguts for more information on how to
               use this function on tied hashes.

                       HE*     hv_fetch_ent(HV* tb, SV* key, I32 lval, U32 hash)

       hv_iterinit
               Prepares a starting point to traverse a hash
               table.  Returns the number of keys in the hash
               (i.e. the same as "HvKEYS(tb)").  The return value
               is currently only meaningful for hashes without
               tie magic.

               NOTE: Before version 5.004_65, "hv_iterinit" used
               to return the number of hash buckets that happen
               to be in use.  If you still need that esoteric
               value, you can get it through the macro
               "HvFILL(tb)".

                       I32     hv_iterinit(HV* tb)

       hv_iterkey
               Returns the key from the current position of the
               hash iterator.  See "hv_iterinit".

                       char*   hv_iterkey(HE* entry, I32* retlen)

       hv_iterkeysv
               Returns the key as an "SV*" from the current posi­
               entry is deleted from the hash with your iterator
               holding the last reference to it.  Your iterator
               is flagged to free the entry on the next call to
               "hv_iternext", so you must not discard your itera­
               tor immediately else the entry will leak - call
               "hv_iternext" to trigger the resource dealloca­
               tion.

                       HE*     hv_iternext(HV* tb)

       hv_iternextsv
               Performs an "hv_iternext", "hv_iterkey", and
               "hv_iterval" in one operation.

                       SV*     hv_iternextsv(HV* hv, char** key, I32* retlen)

       hv_iternext_flags
               Returns entries from a hash iterator.  See
               "hv_iterinit" and "hv_iternext".  The "flags"
               value will normally be zero; if HV_ITERNEXT_WANT­
               PLACEHOLDERS is set the placeholders keys (for
               restricted hashes) will be returned in addition to
               normal keys. By default placeholders are automati­
               cally skipped over.  Currently a placeholder is
               implemented with a value that is &Perl_sv_place­
               holder. Note that the implementation of placehold­
               ers and restricted hashes may change, and the
               implementation currently is insufficiently
               abstracted for any change to be tidy.

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

                       HE*     hv_iternext_flags(HV* tb, I32 flags)

       hv_iterval
               Returns the value from the current position of the
               hash iterator.  See "hv_iterkey".

                       SV*     hv_iterval(HV* tb, HE* entry)

       hv_magic
               Adds magic to a hash.  See "sv_magic".

                       void    hv_magic(HV* hv, GV* gv, int how)

       hv_store
               Stores an SV in a hash.  The hash key is specified
               as "key" and "klen" is the length of the key.  The
               "hash" parameter is the precomputed hash value; if
               it is zero then Perl will compute it.  The return
               value will be NULL if the operation failed or if
               as a call to hv_store_ent, and does not create a
               temporary SV for the key, so if your key data is
               not already in SV form then use hv_store in pref­
               erence to hv_store_ent.

               See "Understanding the Magic of Tied Hashes and
               Arrays" in perlguts for more information on how to
               use this function on tied hashes.

                       SV**    hv_store(HV* tb, const char* key, I32 klen, SV* val, U32 hash)

       hv_store_ent
               Stores "val" in a hash.  The hash key is specified
               as "key".  The "hash" parameter is the precomputed
               hash value; if it is zero then Perl will compute
               it.  The return value is the new hash entry so
               created.  It will be NULL if the operation failed
               or if the value did not need to be actually stored
               within the hash (as in the case of tied hashes).
               Otherwise the contents of the return value can be
               accessed using the "He?" macros described here.
               Note that the caller is responsible for suitably
               incrementing the reference count of "val" before
               the call, and decrementing it if the function
               returned NULL.  Effectively a successful
               hv_store_ent takes ownership of one reference to
               "val".  This is usually what you want; a newly
               created SV has a reference count of one, so if all
               your code does is create SVs then store them in a
               hash, hv_store will own the only reference to the
               new SV, and your code doesn't need to do anything
               further to tidy up.  Note that hv_store_ent only
               reads the "key"; unlike "val" it does not take
               ownership of it, so maintaining the correct refer­
               ence count on "key" is entirely the caller's
               responsibility.  hv_store is not implemented as a
               call to hv_store_ent, and does not create a tempo­
               rary SV for the key, so if your key data is not
               already in SV form then use hv_store in preference
               to hv_store_ent.

               See "Understanding the Magic of Tied Hashes and
               Arrays" in perlguts for more information on how to
               use this function on tied hashes.

                       HE*     hv_store_ent(HV* tb, SV* key, SV* val, U32 hash)

       hv_undef
               Undefines the hash.

                       void    hv_undef(HV* tb)

       mg_copy Copies the magic from one SV to another.  See
               "sv_magic".

                       int     mg_copy(SV* sv, SV* nsv, const char* key, I32 klen)

       mg_find Finds the magic pointer for type matching the SV.
               See "sv_magic".

                       MAGIC*  mg_find(SV* sv, int type)

       mg_free Free any magic storage used by the SV.  See
               "sv_magic".

                       int     mg_free(SV* sv)

       mg_get  Do magic after a value is retrieved from the SV.
               See "sv_magic".

                       int     mg_get(SV* sv)

       mg_length
               Report on the SV's length.  See "sv_magic".

                       U32     mg_length(SV* sv)

       mg_magical
               Turns on the magical status of an SV.  See
               "sv_magic".

                       void    mg_magical(SV* sv)

       mg_set  Do magic after a value is assigned to the SV.  See
               "sv_magic".

                       int     mg_set(SV* sv)

       SvGETMAGIC
               Invokes "mg_get" on an SV if it has 'get' magic.
               This macro evaluates its argument more than once.

                       void    SvGETMAGIC(SV* sv)

       SvLOCK  Arranges for a mutual exclusion lock to be
               obtained on sv if a suitable module has been
               loaded.

                       void    SvLOCK(SV* sv)

       SvSETMAGIC
               Invokes "mg_set" on an SV if it has 'set' magic.
               This macro evaluates its argument more than once.

       SvSetSV Calls "sv_setsv" if dsv is not the same as ssv.
               May evaluate arguments more than once.

                       void    SvSetSV(SV* dsb, SV* ssv)

       SvSetSV_nosteal
               Calls a non-destructive version of "sv_setsv" if
               dsv is not the same as ssv. May evaluate arguments
               more than once.

                       void    SvSetSV_nosteal(SV* dsv, SV* ssv)

       SvSHARE Arranges for sv to be shared between threads if a
               suitable module has been loaded.

                       void    SvSHARE(SV* sv)


Memory Management

       Copy    The XSUB-writer's interface to the C "memcpy"
               function.  The "src" is the source, "dest" is the
               destination, "nitems" is the number of items, and
               "type" is the type.  May fail on overlapping
               copies.  See also "Move".

                       void    Copy(void* src, void* dest, int nitems, type)

       Move    The XSUB-writer's interface to the C "memmove"
               function.  The "src" is the source, "dest" is the
               destination, "nitems" is the number of items, and
               "type" is the type.  Can do overlapping moves.
               See also "Copy".

                       void    Move(void* src, void* dest, int nitems, type)

       New     The XSUB-writer's interface to the C "malloc"
               function.

                       void    New(int id, void* ptr, int nitems, type)

       Newc    The XSUB-writer's interface to the C "malloc"
               function, with cast.

                       void    Newc(int id, void* ptr, int nitems, type, cast)

       NEWSV   Creates a new SV.  A non-zero "len" parameter
               indicates the number of bytes of preallocated
               string space the SV should have.  An extra byte
               for a tailing NUL is also reserved.  (SvPOK is not
               set for the SV even if string space is allocated.)
               The reference count for the new SV is set to 1.
               "id" is an integer id between 0 and 1299 (used to
               identify leaks).

       Renew   The XSUB-writer's interface to the C "realloc"
               function.

                       void    Renew(void* ptr, int nitems, type)

       Renewc  The XSUB-writer's interface to the C "realloc"
               function, with cast.

                       void    Renewc(void* ptr, int nitems, type, cast)

       Safefree
               The XSUB-writer's interface to the C "free" func­
               tion.

                       void    Safefree(void* ptr)

       savepv  Perl's version of "strdup()". Returns a pointer to
               a newly allocated string which is a duplicate of
               "pv". The size of the string is determined by
               "strlen()". The memory allocated for the new
               string can be freed with the "Safefree()" func­
               tion.

                       char*   savepv(const char* pv)

       savepvn Perl's version of what "strndup()" would be if it
               existed. Returns a pointer to a newly allocated
               string which is a duplicate of the first "len"
               bytes from "pv". The memory allocated for the new
               string can be freed with the "Safefree()" func­
               tion.

                       char*   savepvn(const char* pv, I32 len)

       savesharedpv
               A version of "savepv()" which allocates the dupli­
               cate string in memory which is shared between
               threads.

                       char*   savesharedpv(const char* pv)

       StructCopy
               This is an architecture-independent macro to copy
               one structure to another.

                       void    StructCopy(type src, type dest, type)

       Zero    The XSUB-writer's interface to the C "memzero"
               function.  The "dest" is the destination, "nitems"
               is the number of items, and "type" is the type.

               does not have to be fbm_compiled, but the search
               will not be as fast then.

                       char*   fbm_instr(unsigned char* big, unsigned char* bigend, SV* littlesv, U32 flags)

       form    Takes a sprintf-style format pattern and conven­
               tional (non-SV) arguments and returns the format­
               ted string.

                   (char *) Perl_form(pTHX_ const char* pat, ...)

               can be used any place a string (char *) is
               required:

                   char * s = Perl_form("%d.%d",major,minor);

               Uses a single private buffer so if you want to
               format several strings you must explicitly copy
               the earlier strings away (and free the copies when
               you are done).

                       char*   form(const char* pat, ...)

       getcwd_sv
               Fill the sv with current working directory

                       int     getcwd_sv(SV* sv)

       strEQ   Test two strings to see if they are equal.
               Returns true or false.

                       bool    strEQ(char* s1, char* s2)

       strGE   Test two strings to see if the first, "s1", is
               greater than or equal to the second, "s2".
               Returns true or false.

                       bool    strGE(char* s1, char* s2)

       strGT   Test two strings to see if the first, "s1", is
               greater than the second, "s2".  Returns true or
               false.

                       bool    strGT(char* s1, char* s2)

       strLE   Test two strings to see if the first, "s1", is
               less than or equal to the second, "s2".  Returns
               true or false.

                       bool    strLE(char* s1, char* s2)

       strLT   Test two strings to see if the first, "s1", is

                       bool    strnEQ(char* s1, char* s2, STRLEN len)

       strnNE  Test two strings to see if they are different.
               The "len" parameter indicates the number of bytes
               to compare.  Returns true or false. (A wrapper for
               "strncmp").

                       bool    strnNE(char* s1, char* s2, STRLEN len)

       sv_nolocking
               Dummy routine which "locks" an SV when there is no
               locking module present.  Exists to avoid test for
               a NULL function pointer and because it could
               potentially warn under some level of strict-ness.

                       void    sv_nolocking(SV *)

       sv_nosharing
               Dummy routine which "shares" an SV when there is
               no sharing module present.  Exists to avoid test
               for a NULL function pointer and because it could
               potentially warn under some level of strict-ness.

                       void    sv_nosharing(SV *)

       sv_nounlocking
               Dummy routine which "unlocks" an SV when there is
               no locking module present.  Exists to avoid test
               for a NULL function pointer and because it could
               potentially warn under some level of strict-ness.

                       void    sv_nounlocking(SV *)


Numeric functions

       grok_bin
               converts a string representing a binary number to
               numeric form.

               On entry start and *len give the string to scan,
               *flags gives conversion flags, and result should
               be NULL or a pointer to an NV.  The scan stops at
               the end of the string, or the first invalid char­
               acter.  On return *len is set to the length
               scanned string, and *flags gives output flags.

               If the value is <= UV_MAX it is returned as a UV,
               the output flags are clear, and nothing is written
               to *result. If the value is > UV_MAX "grok_bin"
               returns UV_MAX, sets
               "PERL_SCAN_GREATER_THAN_UV_MAX" in the output
               flags, and writes the value to *result (or the
               On entry start and *len give the string to scan,
               *flags gives conversion flags, and result should
               be NULL or a pointer to an NV.  The scan stops at
               the end of the string, or the first non-hex-digit
               character.  On return *len is set to the length
               scanned string, and *flags gives output flags.

               If the value is <= UV_MAX it is returned as a UV,
               the output flags are clear, and nothing is written
               to *result. If the value is > UV_MAX "grok_hex"
               returns UV_MAX, sets
               "PERL_SCAN_GREATER_THAN_UV_MAX" in the output
               flags, and writes the value to *result (or the
               value is discarded if result is NULL).

               The hex number may optionally be prefixed with
               "0x" or "x" unless "PERL_SCAN_DISALLOW_PREFIX" is
               set in *flags on entry. If "PERL_SCAN_ALLOW_UNDER­
               SCORES" is set in *flags then the hex number may
               use '_' characters to separate digits.

                       UV      grok_hex(char* start, STRLEN* len, I32* flags, NV *result)

       grok_number
               Recognise (or not) a number.  The type of the num­
               ber is returned (0 if unrecognised), otherwise it
               is a bit-ORed combination of IS_NUMBER_IN_UV,
               IS_NUMBER_GREATER_THAN_UV_MAX, IS_NUMBER_NOT_INT,
               IS_NUMBER_NEG, IS_NUMBER_INFINITY, IS_NUMBER_NAN
               (defined in perl.h).

               If the value of the number can fit an in UV, it is
               returned in the *valuep IS_NUMBER_IN_UV will be
               set to indicate that *valuep is valid, IS_NUM­
               BER_IN_UV will never be set unless *valuep is
               valid, but *valuep may have been assigned to dur­
               ing processing even though IS_NUMBER_IN_UV is not
               set on return.  If valuep is NULL, IS_NUMBER_IN_UV
               will be set for the same cases as when valuep is
               non-NULL, but no actual assignment (or SEGV) will
               occur.

               IS_NUMBER_NOT_INT will be set with IS_NUMBER_IN_UV
               if trailing decimals were seen (in which case
               *valuep gives the true value truncated to an inte­
               ger), and IS_NUMBER_NEG if the number is negative
               (in which case *valuep holds the absolute value).
               IS_NUMBER_IN_UV is not set if e notation was used
               or the number is larger than a UV.

                       int     grok_number(const char *pv, STRLEN len, UV *valuep)


       scan_hex
               For backwards compatibility. Use "grok_hex"
               instead.

                       NV      scan_hex(char* start, STRLEN len, STRLEN* retlen)

       scan_oct
               For backwards compatibility. Use "grok_oct"
               instead.

                       NV      scan_oct(char* start, STRLEN len, STRLEN* retlen)


Optree Manipulation Functions

       cv_const_sv
               If "cv" is a constant sub eligible for inlining.
               returns the constant value returned by the sub.
               Otherwise, returns NULL.

               Constant subs can be created with "newCONSTSUB" or
               as described in "Constant Functions" in perlsub.

                       SV*     cv_const_sv(CV* cv)

       newCONSTSUB
               Creates a constant sub equivalent to Perl "sub FOO
               () { 123 }" which is eligible for inlining at com­
               pile-time.

                       CV*     newCONSTSUB(HV* stash, char* name, SV* sv)

       newXS   Used by "xsubpp" to hook up XSUBs as Perl subs.


Pad Data Structures

       pad_sv  Get the value at offset po in the current pad.
               Use macro PAD_SV instead of calling this function
               directly.

                       SV*     pad_sv(PADOFFSET po)


Stack Manipulation Macros

       dMARK   Declare a stack marker variable, "mark", for the
               XSUB.  See "MARK" and "dORIGMARK".

                               dMARK;

       dORIGMARK
               Saves the original stack mark for the XSUB.  See
               "ORIGMARK".

                               dORIGMARK;

       ORIGMARK
               The original stack mark for the XSUB.  See "dORIG­
               MARK".

       POPi    Pops an integer off the stack.

                       IV      POPi

       POPl    Pops a long off the stack.

                       long    POPl

       POPn    Pops a double off the stack.

                       NV      POPn

       POPp    Pops a string off the stack. Deprecated. New code
               should provide a STRLEN n_a and use POPpx.

                       char*   POPp

       POPpbytex
               Pops a string off the stack which must consist of
               bytes i.e. characters < 256.  Requires a variable
               STRLEN n_a in scope.

                       char*   POPpbytex

       POPpx   Pops a string off the stack.  Requires a variable
               STRLEN n_a in scope.

                       char*   POPpx

       POPs    Pops an SV off the stack.

                       SV*     POPs

       PUSHi   Push an integer onto the stack.  The stack must
               have room for this element.  Handles 'set' magic.
               See "XPUSHi".

                       void    PUSHi(IV iv)

       PUSHMARK
               Opening bracket for arguments on a callback.  See
               "PUTBACK" and perlcall.

                               PUSHMARK;

       PUSHn   Push a double onto the stack.  The stack must have
               room for this element.  Handles 'set' magic.  See
               "XPUSHn".
                       void    PUSHs(SV* sv)

       PUSHu   Push an unsigned integer onto the stack.  The
               stack must have room for this element.  See
               "XPUSHu".

                       void    PUSHu(UV uv)

       PUTBACK Closing bracket for XSUB arguments.  This is usu­
               ally handled by "xsubpp".  See "PUSHMARK" and
               perlcall for other uses.

                               PUTBACK;

       SP      Stack pointer.  This is usually handled by
               "xsubpp".  See "dSP" and "SPAGAIN".

       SPAGAIN Refetch the stack pointer.  Used after a callback.
               See perlcall.

                               SPAGAIN;

       XPUSHi  Push an integer onto the stack, extending the
               stack if necessary.  Handles 'set' magic. See
               "PUSHi".

                       void    XPUSHi(IV iv)

       XPUSHn  Push a double onto the stack, extending the stack
               if necessary.  Handles 'set' magic.  See "PUSHn".

                       void    XPUSHn(NV nv)

       XPUSHp  Push a string onto the stack, extending the stack
               if necessary.  The "len" indicates the length of
               the string.  Handles 'set' magic.  See "PUSHp".

                       void    XPUSHp(char* str, STRLEN len)

       XPUSHs  Push an SV onto the stack, extending the stack if
               necessary.  Does not handle 'set' magic.  See
               "PUSHs".

                       void    XPUSHs(SV* sv)

       XPUSHu  Push an unsigned integer onto the stack, extending
               the stack if necessary.  See "PUSHu".

                       void    XPUSHu(UV uv)

       XSRETURN
               Return from XSUB, indicating number of items on
                               XSRETURN_NO;

       XSRETURN_NV
               Return a double from an XSUB immediately.  Uses
               "XST_mNV".

                       void    XSRETURN_NV(NV nv)

       XSRETURN_PV
               Return a copy of a string from an XSUB immedi­
               ately.  Uses "XST_mPV".

                       void    XSRETURN_PV(char* str)

       XSRETURN_UNDEF
               Return &PL_sv_undef from an XSUB immediately.
               Uses "XST_mUNDEF".

                               XSRETURN_UNDEF;

       XSRETURN_UV
               Return an integer from an XSUB immediately.  Uses
               "XST_mUV".

                       void    XSRETURN_UV(IV uv)

       XSRETURN_YES
               Return &PL_sv_yes from an XSUB immediately.  Uses
               "XST_mYES".

                               XSRETURN_YES;

       XST_mIV Place an integer into the specified position "pos"
               on the stack.  The value is stored in a new mortal
               SV.

                       void    XST_mIV(int pos, IV iv)

       XST_mNO Place &PL_sv_no into the specified position "pos"
               on the stack.

                       void    XST_mNO(int pos)

       XST_mNV Place a double into the specified position "pos"
               on the stack.  The value is stored in a new mortal
               SV.

                       void    XST_mNV(int pos, NV nv)

       XST_mPV Place a copy of a string into the specified posi­
               tion "pos" on the stack.  The value is stored in a
               new mortal SV.


SV Flags

       svtype  An enum of flags for Perl types.  These are found
               in the file sv.h in the "svtype" enum.  Test these
               flags with the "SvTYPE" macro.

       SVt_IV  Integer type flag for scalars.  See "svtype".

       SVt_NV  Double type flag for scalars.  See "svtype".

       SVt_PV  Pointer type flag for scalars.  See "svtype".

       SVt_PVAV
               Type flag for arrays.  See "svtype".

       SVt_PVCV
               Type flag for code refs.  See "svtype".

       SVt_PVHV
               Type flag for hashes.  See "svtype".

       SVt_PVMG
               Type flag for blessed scalars.  See "svtype".


SV Manipulation Functions

       get_sv  Returns the SV of the specified Perl scalar.  If
               "create" is set and the Perl variable does not
               exist then it will be created.  If "create" is not
               set and the variable does not exist then NULL is
               returned.

               NOTE: the perl_ form of this function is depre­
               cated.

                       SV*     get_sv(const char* name, I32 create)

       looks_like_number
               Test if the content of an SV looks like a number
               (or is a number).  "Inf" and "Infinity" are
               treated as numbers (so will not issue a non-
               numeric warning), even if your atof() doesn't grok
               them.

                       I32     looks_like_number(SV* sv)

       newRV_inc
               Creates an RV wrapper for an SV.  The reference
               count for the original SV is incremented.

                       SV*     newRV_inc(SV* sv)

       newRV_noinc
                       SV*     newSViv(IV i)

       newSVnv Creates a new SV and copies a floating point value
               into it.  The reference count for the SV is set to
               1.

                       SV*     newSVnv(NV n)

       newSVpv Creates a new SV and copies a string into it.  The
               reference count for the SV is set to 1.  If "len"
               is zero, Perl will compute the length using
               strlen().  For efficiency, consider using
               "newSVpvn" instead.

                       SV*     newSVpv(const char* s, STRLEN len)

       newSVpvf
               Creates a new SV and initializes it with the
               string formatted like "sprintf".

                       SV*     newSVpvf(const char* pat, ...)

       newSVpvn
               Creates a new SV and copies a string into it.  The
               reference count for the SV is set to 1.  Note that
               if "len" is zero, Perl will create a zero length
               string.  You are responsible for ensuring that the
               source string is at least "len" bytes long.

                       SV*     newSVpvn(const char* s, STRLEN len)

       newSVpvn_share
               Creates a new SV with its SvPVX pointing to a
               shared string in the string table. If the string
               does not already exist in the table, it is created
               first.  Turns on READONLY and FAKE.  The string's
               hash is stored in the UV slot of the SV; if the
               "hash" parameter is non-zero, that value is used;
               otherwise the hash is computed.  The idea here is
               that as the string table is used for shared hash
               keys these strings will have SvPVX == HeKEY and
               hash lookup will avoid string compare.

                       SV*     newSVpvn_share(const char* s, I32 len, U32 hash)

       newSVrv Creates a new SV for the RV, "rv", to point to.
               If "rv" is not an RV then it will be upgraded to
               one.  If "classname" is non-null then the new SV
               will be blessed in the specified package.  The new
               SV is returned and its reference count is 1.

                       SV*     newSVrv(SV* rv, const char* classname)

                       STRLEN  SvCUR(SV* sv)

       SvCUR_set
               Set the length of the string which is in the SV.
               See "SvCUR".

                       void    SvCUR_set(SV* sv, STRLEN len)

       SvEND   Returns a pointer to the last character in the
               string which is in the SV.  See "SvCUR".  Access
               the character as *(SvEND(sv)).

                       char*   SvEND(SV* sv)

       SvGROW  Expands the character buffer in the SV so that it
               has room for the indicated number of bytes (remem­
               ber to reserve space for an extra trailing NUL
               character).  Calls "sv_grow" to perform the expan­
               sion if necessary.  Returns a pointer to the char­
               acter buffer.

                       char *  SvGROW(SV* sv, STRLEN len)

       SvIOK   Returns a boolean indicating whether the SV con­
               tains an integer.

                       bool    SvIOK(SV* sv)

       SvIOKp  Returns a boolean indicating whether the SV con­
               tains an integer.  Checks the private setting.
               Use "SvIOK".

                       bool    SvIOKp(SV* sv)

       SvIOK_notUV
               Returns a boolean indicating whether the SV con­
               tains a signed integer.

                       void    SvIOK_notUV(SV* sv)

       SvIOK_off
               Unsets the IV status of an SV.

                       void    SvIOK_off(SV* sv)

       SvIOK_on
               Tells an SV that it is an integer.

                       void    SvIOK_on(SV* sv)

       SvIOK_only

                       void    SvIOK_UV(SV* sv)

       SvIsCOW Returns a boolean indicating whether the SV is
               Copy-On-Write. (either shared hash key scalars, or
               full Copy On Write scalars if 5.9.0 is configured
               for COW)

                       bool    SvIsCOW(SV* sv)

       SvIsCOW_shared_hash
               Returns a boolean indicating whether the SV is
               Copy-On-Write shared hash key scalar.

                       bool    SvIsCOW_shared_hash(SV* sv)

       SvIV    Coerces the given SV to an integer and returns it.
               See  "SvIVx" for a version which guarantees to
               evaluate sv only once.

                       IV      SvIV(SV* sv)

       SvIVX   Returns the raw value in the SV's IV slot, without
               checks or conversions.  Only use when you are sure
               SvIOK is true. See also "SvIV()".

                       IV      SvIVX(SV* sv)

       SvIVx   Coerces the given SV to an integer and returns it.
               Guarantees to evaluate sv only once. Use the more
               efficient "SvIV" otherwise.

                       IV      SvIVx(SV* sv)

       SvLEN   Returns the size of the string buffer in the SV,
               not including any part attributable to "SvOOK".
               See "SvCUR".

                       STRLEN  SvLEN(SV* sv)

       SvNIOK  Returns a boolean indicating whether the SV con­
               tains a number, integer or double.

                       bool    SvNIOK(SV* sv)

       SvNIOKp Returns a boolean indicating whether the SV con­
               tains a number, integer or double.  Checks the
               private setting.  Use "SvNIOK".

                       bool    SvNIOKp(SV* sv)

       SvNIOK_off

       SvNOK_off
               Unsets the NV status of an SV.

                       void    SvNOK_off(SV* sv)

       SvNOK_on
               Tells an SV that it is a double.

                       void    SvNOK_on(SV* sv)

       SvNOK_only
               Tells an SV that it is a double and disables all
               other OK bits.

                       void    SvNOK_only(SV* sv)

       SvNV    Coerce the given SV to a double and return it. See
               "SvNVx" for a version which guarantees to evaluate
               sv only once.

                       NV      SvNV(SV* sv)

       SvNVx   Coerces the given SV to a double and returns it.
               Guarantees to evaluate sv only once. Use the more
               efficient "SvNV" otherwise.

                       NV      SvNVx(SV* sv)

       SvNVX   Returns the raw value in the SV's NV slot, without
               checks or conversions.  Only use when you are sure
               SvNOK is true. See also "SvNV()".

                       NV      SvNVX(SV* sv)

       SvOK    Returns a boolean indicating whether the value is
               an SV.

                       bool    SvOK(SV* sv)

       SvOOK   Returns a boolean indicating whether the SvIVX is
               a valid offset value for the SvPVX.  This hack is
               used internally to speed up removal of characters
               from the beginning of a SvPV.  When SvOOK is true,
               then the start of the allocated string buffer is
               really (SvPVX - SvIVX).

                       bool    SvOOK(SV* sv)

       SvPOK   Returns a boolean indicating whether the SV con­
               tains a character string.

               Tells an SV that it is a string.

                       void    SvPOK_on(SV* sv)

       SvPOK_only
               Tells an SV that it is a string and disables all
               other OK bits.  Will also turn off the UTF-8 sta­
               tus.

                       void    SvPOK_only(SV* sv)

       SvPOK_only_UTF8
               Tells an SV that it is a string and disables all
               other OK bits, and leaves the UTF-8 status as it
               was.

                       void    SvPOK_only_UTF8(SV* sv)

       SvPV    Returns a pointer to the string in the SV, or a
               stringified form of the SV if the SV does not con­
               tain a string.  The SV may cache the stringified
               version becoming "SvPOK".  Handles 'get' magic.
               See also "SvPVx" for a version which guarantees to
               evaluate sv only once.

                       char*   SvPV(SV* sv, STRLEN len)

       SvPVbyte
               Like "SvPV", but converts sv to byte representa­
               tion first if necessary.

                       char*   SvPVbyte(SV* sv, STRLEN len)

       SvPVbytex
               Like "SvPV", but converts sv to byte representa­
               tion first if necessary.  Guarantees to evaluate
               sv only once; use the more efficient "SvPVbyte"
               otherwise.

                       char*   SvPVbytex(SV* sv, STRLEN len)

       SvPVbytex_force
               Like "SvPV_force", but converts sv to byte repre­
               sentation first if necessary.  Guarantees to eval­
               uate sv only once; use the more efficient
               "SvPVbyte_force" otherwise.

                       char*   SvPVbytex_force(SV* sv, STRLEN len)

       SvPVbyte_force
               Like "SvPV_force", but converts sv to byte repre­
               sentation first if necessary.

       SvPVutf8x
               Like "SvPV", but converts sv to utf8 first if nec­
               essary.  Guarantees to evaluate sv only once; use
               the more efficient "SvPVutf8" otherwise.

                       char*   SvPVutf8x(SV* sv, STRLEN len)

       SvPVutf8x_force
               Like "SvPV_force", but converts sv to utf8 first
               if necessary.  Guarantees to evaluate sv only
               once; use the more efficient "SvPVutf8_force" oth­
               erwise.

                       char*   SvPVutf8x_force(SV* sv, STRLEN len)

       SvPVutf8_force
               Like "SvPV_force", but converts sv to utf8 first
               if necessary.

                       char*   SvPVutf8_force(SV* sv, STRLEN len)

       SvPVutf8_nolen
               Like "SvPV_nolen", but converts sv to utf8 first
               if necessary.

                       char*   SvPVutf8_nolen(SV* sv)

       SvPVX   Returns a pointer to the physical string in the
               SV.  The SV must contain a string.

                       char*   SvPVX(SV* sv)

       SvPVx   A version of "SvPV" which guarantees to evaluate
               sv only once.

                       char*   SvPVx(SV* sv, STRLEN len)

       SvPV_force
               Like "SvPV" but will force the SV into containing
               just a string ("SvPOK_only").  You want force if
               you are going to update the "SvPVX" directly.

                       char*   SvPV_force(SV* sv, STRLEN len)

       SvPV_force_nomg
               Like "SvPV" but will force the SV into containing
               just a string ("SvPOK_only").  You want force if
               you are going to update the "SvPVX" directly.
               Doesn't process magic.

                       char*   SvPV_force_nomg(SV* sv, STRLEN len)

       SvREFCNT_dec
               Decrements the reference count of the given SV.

                       void    SvREFCNT_dec(SV* sv)

       SvREFCNT_inc
               Increments the reference count of the given SV.

                       SV*     SvREFCNT_inc(SV* sv)

       SvROK   Tests if the SV is an RV.

                       bool    SvROK(SV* sv)

       SvROK_off
               Unsets the RV status of an SV.

                       void    SvROK_off(SV* sv)

       SvROK_on
               Tells an SV that it is an RV.

                       void    SvROK_on(SV* sv)

       SvRV    Dereferences an RV to return the SV.

                       SV*     SvRV(SV* sv)

       SvSTASH Returns the stash of the SV.

                       HV*     SvSTASH(SV* sv)

       SvTAINT Taints an SV if tainting is enabled.

                       void    SvTAINT(SV* sv)

       SvTAINTED
               Checks to see if an SV is tainted. Returns TRUE if
               it is, FALSE if not.

                       bool    SvTAINTED(SV* sv)

       SvTAINTED_off
               Untaints an SV. Be very careful with this routine,
               as it short-circuits some of Perl's fundamental
               security features. XS module authors should not
               use this function unless they fully understand all
               the implications of unconditionally untainting the
               value. Untainting should be done in the standard
               perl fashion, via a carefully crafted regexp,
               rather than directly untainting variables.


                       svtype  SvTYPE(SV* sv)

       SvUNLOCK
               Releases a mutual exclusion lock on sv if a suit­
               able module has been loaded.

                       void    SvUNLOCK(SV* sv)

       SvUOK   Returns a boolean indicating whether the SV con­
               tains an unsigned integer.

                       void    SvUOK(SV* sv)

       SvUPGRADE
               Used to upgrade an SV to a more complex form.
               Uses "sv_upgrade" to perform the upgrade if neces­
               sary.  See "svtype".

                       void    SvUPGRADE(SV* sv, svtype type)

       SvUTF8  Returns a boolean indicating whether the SV con­
               tains UTF-8 encoded data.

                       void    SvUTF8(SV* sv)

       SvUTF8_off
               Unsets the UTF-8 status of an SV.

                       void    SvUTF8_off(SV *sv)

       SvUTF8_on
               Turn on the UTF-8 status of an SV (the data is not
               changed, just the flag).  Do not use frivolously.

                       void    SvUTF8_on(SV *sv)

       SvUV    Coerces the given SV to an unsigned integer and
               returns it.  See "SvUVx" for a version which guar­
               antees to evaluate sv only once.

                       UV      SvUV(SV* sv)

       SvUVX   Returns the raw value in the SV's UV slot, without
               checks or conversions.  Only use when you are sure
               SvIOK is true. See also "SvUV()".

                       UV      SvUVX(SV* sv)

       SvUVx   Coerces the given SV to an unsigned integer and
               returns it. Guarantees to evaluate sv only once.
               Use the more efficient "SvUV" otherwise.

       sv_2io  Using various gambits, try to get an IO from an
               SV: the IO slot if its a GV; or the recursive
               result if we're an RV; or the IO slot of the sym­
               bol named after the PV if we're a string.

                       IO*     sv_2io(SV* sv)

       sv_2iv  Return the integer value of an SV, doing any nec­
               essary string conversion, magic etc. Normally used
               via the "SvIV(sv)" and "SvIVx(sv)" macros.

                       IV      sv_2iv(SV* sv)

       sv_2mortal
               Marks an existing SV as mortal.  The SV will be
               destroyed "soon", either by an explicit call to
               FREETMPS, or by an implicit call at places such as
               statement boundaries.  See also "sv_newmortal" and
               "sv_mortalcopy".

                       SV*     sv_2mortal(SV* sv)

       sv_2nv  Return the num value of an SV, doing any necessary
               string or integer conversion, magic etc. Normally
               used via the "SvNV(sv)" and "SvNVx(sv)" macros.

                       NV      sv_2nv(SV* sv)

       sv_2pvbyte
               Return a pointer to the byte-encoded representa­
               tion of the SV, and set *lp to its length.  May
               cause the SV to be downgraded from UTF-8 as a
               side-effect.

               Usually accessed via the "SvPVbyte" macro.

                       char*   sv_2pvbyte(SV* sv, STRLEN* lp)

       sv_2pvbyte_nolen
               Return a pointer to the byte-encoded representa­
               tion of the SV.  May cause the SV to be downgraded
               from UTF-8 as a side-effect.

               Usually accessed via the "SvPVbyte_nolen" macro.

                       char*   sv_2pvbyte_nolen(SV* sv)

       sv_2pvutf8
               Return a pointer to the UTF-8-encoded representa­
               tion of the SV, and set *lp to its length.  May
               cause the SV to be upgraded to UTF-8 as a

       sv_2pv_flags
               Returns a pointer to the string value of an SV,
               and sets *lp to its length.  If flags includes
               SV_GMAGIC, does an mg_get() first. Coerces sv to a
               string if necessary.  Normally invoked via the
               "SvPV_flags" macro. "sv_2pv()" and "sv_2pv_nomg"
               usually end up here too.

                       char*   sv_2pv_flags(SV* sv, STRLEN* lp, I32 flags)

       sv_2pv_nolen
               Like "sv_2pv()", but doesn't return the length
               too. You should usually use the macro wrapper
               "SvPV_nolen(sv)" instead.
                    char*     sv_2pv_nolen(SV* sv)

       sv_2uv  Return the unsigned integer value of an SV, doing
               any necessary string conversion, magic etc. Nor­
               mally used via the "SvUV(sv)" and "SvUVx(sv)"
               macros.

                       UV      sv_2uv(SV* sv)

       sv_backoff
               Remove any string offset. You should normally use
               the "SvOOK_off" macro wrapper instead.

                       int     sv_backoff(SV* sv)

       sv_bless
               Blesses an SV into a specified package.  The SV
               must be an RV.  The package must be designated by
               its stash (see "gv_stashpv()").  The reference
               count of the SV is unaffected.

                       SV*     sv_bless(SV* sv, HV* stash)

       sv_catpv
               Concatenates the string onto the end of the string
               which is in the SV.  If the SV has the UTF-8 sta­
               tus set, then the bytes appended should be valid
               UTF-8.  Handles 'get' magic, but not 'set' magic.
               See "sv_catpv_mg".

                       void    sv_catpv(SV* sv, const char* ptr)

       sv_catpvf
               Processes its arguments like "sprintf" and appends
               the formatted output to an SV.  If the appended
               data contains "wide" characters (including, but
               not limited to, SVs with a UTF-8 PV formatted with
               Concatenates the string onto the end of the string
               which is in the SV.  The "len" indicates number of
               bytes to copy.  If the SV has the UTF-8 status
               set, then the bytes appended should be valid
               UTF-8.  Handles 'get' magic, but not 'set' magic.
               See "sv_catpvn_mg".

                       void    sv_catpvn(SV* sv, const char* ptr, STRLEN len)

       sv_catpvn_flags
               Concatenates the string onto the end of the string
               which is in the SV.  The "len" indicates number of
               bytes to copy.  If the SV has the UTF-8 status
               set, then the bytes appended should be valid
               UTF-8.  If "flags" has "SV_GMAGIC" bit set, will
               "mg_get" on "dsv" if appropriate, else not.
               "sv_catpvn" and "sv_catpvn_nomg" are implemented
               in terms of this function.

                       void    sv_catpvn_flags(SV* sv, const char* ptr, STRLEN len, I32 flags)

       sv_catpvn_mg
               Like "sv_catpvn", but also handles 'set' magic.

                       void    sv_catpvn_mg(SV *sv, const char *ptr, STRLEN len)

       sv_catpv_mg
               Like "sv_catpv", but also handles 'set' magic.

                       void    sv_catpv_mg(SV *sv, const char *ptr)

       sv_catsv
               Concatenates the string from SV "ssv" onto the end
               of the string in SV "dsv".  Modifies "dsv" but not
               "ssv".  Handles 'get' magic, but not 'set' magic.
               See "sv_catsv_mg".

                       void    sv_catsv(SV* dsv, SV* ssv)

       sv_catsv_flags
               Concatenates the string from SV "ssv" onto the end
               of the string in SV "dsv".  Modifies "dsv" but not
               "ssv".  If "flags" has "SV_GMAGIC" bit set, will
               "mg_get" on the SVs if appropriate, else not.
               "sv_catsv" and "sv_catsv_nomg" are implemented in
               terms of this function.

                       void    sv_catsv_flags(SV* dsv, SV* ssv, I32 flags)

       sv_catsv_mg
               Like "sv_catsv", but also handles 'set' magic.

               Clear an SV: call any destructors, free up any
               memory used by the body, and free the body itself.
               The SV's head is not freed, although its type is
               set to all 1's so that it won't inadvertently be
               assumed to be live during global destruction etc.
               This function should only be called when REFCNT is
               zero. Most of the time you'll want to call
               "sv_free()" (or its macro wrapper "SvREFCNT_dec")
               instead.

                       void    sv_clear(SV* sv)

       sv_cmp  Compares the strings in two SVs.  Returns -1, 0,
               or 1 indicating whether the string in "sv1" is
               less than, equal to, or greater than the string in
               "sv2". Is UTF-8 and 'use bytes' aware, handles get
               magic, and will coerce its args to strings if nec­
               essary.  See also "sv_cmp_locale".

                       I32     sv_cmp(SV* sv1, SV* sv2)

       sv_cmp_locale
               Compares the strings in two SVs in a locale-aware
               manner. Is UTF-8 and 'use bytes' aware, handles
               get magic, and will coerce its args to strings if
               necessary.  See also "sv_cmp_locale".  See also
               "sv_cmp".

                       I32     sv_cmp_locale(SV* sv1, SV* sv2)

       sv_collxfrm
               Add Collate Transform magic to an SV if it doesn't
               already have it.

               Any scalar variable may carry PERL_MAGIC_collxfrm
               magic that contains the scalar data of the vari­
               able, but transformed to such a format that a nor­
               mal memory comparison can be used to compare the
               data according to the locale settings.

                       char*   sv_collxfrm(SV* sv, STRLEN* nxp)

       sv_copypv
               Copies a stringified representation of the source
               SV into the destination SV.  Automatically per­
               forms any necessary mg_get and coercion of numeric
               values into strings.  Guaranteed to preserve UTF-8
               flag even from overloaded objects.  Similar in
               nature to sv_2pv[_flags] but operates directly on
               an SV instead of just the string.  Mostly uses
               sv_2pv_flags to do its work, except when that
               would lose the UTF-8'ness of the PV.

                       bool    sv_derived_from(SV* sv, const char* name)

       sv_eq   Returns a boolean indicating whether the strings
               in the two SVs are identical. Is UTF-8 and 'use
               bytes' aware, handles get magic, and will coerce
               its args to strings if necessary.

                       I32     sv_eq(SV* sv1, SV* sv2)

       sv_force_normal
               Undo various types of fakery on an SV: if the PV
               is a shared string, make a private copy; if we're
               a ref, stop refing; if we're a glob, downgrade to
               an xpvmg. See also "sv_force_normal_flags".

                       void    sv_force_normal(SV *sv)

       sv_force_normal_flags
               Undo various types of fakery on an SV: if the PV
               is a shared string, make a private copy; if we're
               a ref, stop refing; if we're a glob, downgrade to
               an xpvmg. The "flags" parameter gets passed to
               "sv_unref_flags()" when unrefing. "sv_force_nor­
               mal" calls this function with flags set to 0.

                       void    sv_force_normal_flags(SV *sv, U32 flags)

       sv_free Decrement an SV's reference count, and if it drops
               to zero, call "sv_clear" to invoke destructors and
               free up any memory used by the body; finally,
               deallocate the SV's head itself.  Normally called
               via a wrapper macro "SvREFCNT_dec".

                       void    sv_free(SV* sv)

       sv_gets Get a line from the filehandle and store it into
               the SV, optionally appending to the currently-
               stored string.

                       char*   sv_gets(SV* sv, PerlIO* fp, I32 append)

       sv_grow Expands the character buffer in the SV.  If neces­
               sary, uses "sv_unref" and upgrades the SV to
               "SVt_PV".  Returns a pointer to the character
               buffer.  Use the "SvGROW" wrapper instead.

                       char*   sv_grow(SV* sv, STRLEN newlen)

       sv_inc  Auto-increment of the value in the SV, doing
               string to numeric conversion if necessary. Handles
               'get' magic.

                       int     sv_isa(SV* sv, const char* name)

       sv_isobject
               Returns a boolean indicating whether the SV is an
               RV pointing to a blessed object.  If the SV is not
               an RV, or if the object is not blessed, then this
               will return false.

                       int     sv_isobject(SV* sv)

       sv_iv   A private implementation of the "SvIVx" macro for
               compilers which can't cope with complex macro
               expressions. Always use the macro instead.

                       IV      sv_iv(SV* sv)

       sv_len  Returns the length of the string in the SV. Han­
               dles magic and type coercion.  See also "SvCUR",
               which gives raw access to the xpv_cur slot.

                       STRLEN  sv_len(SV* sv)

       sv_len_utf8
               Returns the number of characters in the string in
               an SV, counting wide UTF-8 bytes as a single char­
               acter. Handles magic and type coercion.

                       STRLEN  sv_len_utf8(SV* sv)

       sv_magic
               Adds magic to an SV. First upgrades "sv" to type
               "SVt_PVMG" if necessary, then adds a new magic
               item of type "how" to the head of the magic list.

                       void    sv_magic(SV* sv, SV* obj, int how, const char* name, I32 namlen)

       sv_magicext
               Adds magic to an SV, upgrading it if necessary.
               Applies the supplied vtable and returns pointer to
               the magic added.

               Note that sv_magicext will allow things that
               sv_magic will not.  In particular you can add
               magic to SvREADONLY SVs and and more than one
               instance of the same 'how'

               I "namelen" is greater then zero then a savepvn()
               copy of "name" is stored, if "namelen" is zero
               then "name" is stored as-is and - as another spe­
               cial case - if "(name && namelen == HEf_SVKEY)"
               then "name" is assumed to contain an "SV*" and has
                       SV*     sv_mortalcopy(SV* oldsv)

       sv_newmortal
               Creates a new null SV which is mortal.  The refer­
               ence count of the SV is set to 1. It will be
               destroyed "soon", either by an explicit call to
               FREETMPS, or by an implicit call at places such as
               statement boundaries.  See also "sv_mortalcopy"
               and "sv_2mortal".

                       SV*     sv_newmortal()

       sv_newref
               Increment an SV's reference count. Use the "SvRE­
               FCNT_inc()" wrapper instead.

                       SV*     sv_newref(SV* sv)

       sv_nv   A private implementation of the "SvNVx" macro for
               compilers which can't cope with complex macro
               expressions. Always use the macro instead.

                       NV      sv_nv(SV* sv)

       sv_pos_b2u
               Converts the value pointed to by offsetp from a
               count of bytes from the start of the string, to a
               count of the equivalent number of UTF-8 chars.
               Handles magic and type coercion.

                       void    sv_pos_b2u(SV* sv, I32* offsetp)

       sv_pos_u2b
               Converts the value pointed to by offsetp from a
               count of UTF-8 chars from the start of the string,
               to a count of the equivalent number of bytes; if
               lenp is non-zero, it does the same to lenp, but
               this time starting from the offset, rather than
               from the start of the string. Handles magic and
               type coercion.

                       void    sv_pos_u2b(SV* sv, I32* offsetp, I32* lenp)

       sv_pv   Use the "SvPV_nolen" macro instead

                       char*   sv_pv(SV *sv)

       sv_pvbyte
               Use "SvPVbyte_nolen" instead.

                       char*   sv_pvbyte(SV *sv)

       sv_pvn  A private implementation of the "SvPV" macro for
               compilers which can't cope with complex macro
               expressions. Always use the macro instead.

                       char*   sv_pvn(SV *sv, STRLEN *len)

       sv_pvn_force
               Get a sensible string out of the SV somehow.  A
               private implementation of the "SvPV_force" macro
               for compilers which can't cope with complex macro
               expressions. Always use the macro instead.

                       char*   sv_pvn_force(SV* sv, STRLEN* lp)

       sv_pvn_force_flags
               Get a sensible string out of the SV somehow.  If
               "flags" has "SV_GMAGIC" bit set, will "mg_get" on
               "sv" if appropriate, else not. "sv_pvn_force" and
               "sv_pvn_force_nomg" are implemented in terms of
               this function.  You normally want to use the vari­
               ous wrapper macros instead: see "SvPV_force" and
               "SvPV_force_nomg"

                       char*   sv_pvn_force_flags(SV* sv, STRLEN* lp, I32 flags)

       sv_pvutf8
               Use the "SvPVutf8_nolen" macro instead

                       char*   sv_pvutf8(SV *sv)

       sv_pvutf8n
               A private implementation of the "SvPVutf8" macro
               for compilers which can't cope with complex macro
               expressions. Always use the macro instead.

                       char*   sv_pvutf8n(SV *sv, STRLEN *len)

       sv_pvutf8n_force
               A private implementation of the "SvPVutf8_force"
               macro for compilers which can't cope with complex
               macro expressions. Always use the macro instead.

                       char*   sv_pvutf8n_force(SV* sv, STRLEN* lp)

       sv_reftype
               Returns a string describing what the SV is a ref­
               erence to.

                       char*   sv_reftype(SV* sv, int ob)

       sv_replace
               Make the first argument a copy of the second, then

                       void    sv_report_used()

       sv_reset
               Underlying implementation for the "reset" Perl
               function.  Note that the perl-level function is
               vaguely deprecated.

                       void    sv_reset(char* s, HV* stash)

       sv_rvweaken
               Weaken a reference: set the "SvWEAKREF" flag on
               this RV; give the referred-to SV "PERL_MAGIC_back­
               ref" magic if it hasn't already; and push a back-
               reference to this RV onto the array of backrefer­
               ences associated with that magic.

                       SV*     sv_rvweaken(SV *sv)

       sv_setiv
               Copies an integer into the given SV, upgrading
               first if necessary.  Does not handle 'set' magic.
               See also "sv_setiv_mg".

                       void    sv_setiv(SV* sv, IV num)

       sv_setiv_mg
               Like "sv_setiv", but also handles 'set' magic.

                       void    sv_setiv_mg(SV *sv, IV i)

       sv_setnv
               Copies a double into the given SV, upgrading first
               if necessary.  Does not handle 'set' magic.  See
               also "sv_setnv_mg".

                       void    sv_setnv(SV* sv, NV num)

       sv_setnv_mg
               Like "sv_setnv", but also handles 'set' magic.

                       void    sv_setnv_mg(SV *sv, NV num)

       sv_setpv
               Copies a string into an SV.  The string must be
               null-terminated.  Does not handle 'set' magic.
               See "sv_setpv_mg".

                       void    sv_setpv(SV* sv, const char* ptr)

       sv_setpvf
               Processes its arguments like "sprintf" and sets an

                       void    sv_setpviv(SV* sv, IV num)

       sv_setpviv_mg
               Like "sv_setpviv", but also handles 'set' magic.

                       void    sv_setpviv_mg(SV *sv, IV iv)

       sv_setpvn
               Copies a string into an SV.  The "len" parameter
               indicates the number of bytes to be copied.  Does
               not handle 'set' magic.  See "sv_setpvn_mg".

                       void    sv_setpvn(SV* sv, const char* ptr, STRLEN len)

       sv_setpvn_mg
               Like "sv_setpvn", but also handles 'set' magic.

                       void    sv_setpvn_mg(SV *sv, const char *ptr, STRLEN len)

       sv_setpv_mg
               Like "sv_setpv", but also handles 'set' magic.

                       void    sv_setpv_mg(SV *sv, const char *ptr)

       sv_setref_iv
               Copies an integer into a new SV, optionally bless­
               ing the SV.  The "rv" argument will be upgraded to
               an RV.  That RV will be modified to point to the
               new SV.  The "classname" argument indicates the
               package for the blessing.  Set "classname" to
               "Nullch" to avoid the blessing.  The new SV will
               have a reference count of 1, and the RV will be
               returned.

                       SV*     sv_setref_iv(SV* rv, const char* classname, IV iv)

       sv_setref_nv
               Copies a double into a new SV, optionally blessing
               the SV.  The "rv" argument will be upgraded to an
               RV.  That RV will be modified to point to the new
               SV.  The "classname" argument indicates the pack­
               age for the blessing.  Set "classname" to "Nullch"
               to avoid the blessing.  The new SV will have a
               reference count of 1, and the RV will be returned.

                       SV*     sv_setref_nv(SV* rv, const char* classname, NV nv)

       sv_setref_pv
               Copies a pointer into a new SV, optionally bless­
               ing the SV.  The "rv" argument will be upgraded to
               an RV.  That RV will be modified to point to the
                       SV*     sv_setref_pv(SV* rv, const char* classname, void* pv)

       sv_setref_pvn
               Copies a string into a new SV, optionally blessing
               the SV.  The length of the string must be speci­
               fied with "n".  The "rv" argument will be upgraded
               to an RV.  That RV will be modified to point to
               the new SV.  The "classname" argument indicates
               the package for the blessing.  Set "classname" to
               "Nullch" to avoid the blessing.  The new SV will
               have a reference count of 1, and the RV will be
               returned.

               Note that "sv_setref_pv" copies the pointer while
               this copies the string.

                       SV*     sv_setref_pvn(SV* rv, const char* classname, char* pv, STRLEN n)

       sv_setref_uv
               Copies an unsigned integer into a new SV, option­
               ally blessing the SV.  The "rv" argument will be
               upgraded to an RV.  That RV will be modified to
               point to the new SV.  The "classname" argument
               indicates the package for the blessing.  Set
               "classname" to "Nullch" to avoid the blessing.
               The new SV will have a reference count of 1, and
               the RV will be returned.

                       SV*     sv_setref_uv(SV* rv, const char* classname, UV uv)

       sv_setsv
               Copies the contents of the source SV "ssv" into
               the destination SV "dsv".  The source SV may be
               destroyed if it is mortal, so don't use this func­
               tion if the source SV needs to be reused. Does not
               handle 'set' magic.  Loosely speaking, it performs
               a copy-by-value, obliterating any previous content
               of the destination.

               You probably want to use one of the assortment of
               wrappers, such as "SvSetSV", "SvSetSV_nosteal",
               "SvSetMagicSV" and "SvSetMagicSV_nosteal".

                       void    sv_setsv(SV* dsv, SV* ssv)

       sv_setsv_flags
               Copies the contents of the source SV "ssv" into
               the destination SV "dsv".  The source SV may be
               destroyed if it is mortal, so don't use this func­
               tion if the source SV needs to be reused. Does not
               handle 'set' magic.  Loosely speaking, it performs
               a copy-by-value, obliterating any previous content
                       void    sv_setsv_flags(SV* dsv, SV* ssv, I32 flags)

       sv_setsv_mg
               Like "sv_setsv", but also handles 'set' magic.

                       void    sv_setsv_mg(SV *dstr, SV *sstr)

       sv_setuv
               Copies an unsigned integer into the given SV,
               upgrading first if necessary.  Does not handle
               'set' magic.  See also "sv_setuv_mg".

                       void    sv_setuv(SV* sv, UV num)

       sv_setuv_mg
               Like "sv_setuv", but also handles 'set' magic.

                       void    sv_setuv_mg(SV *sv, UV u)

       sv_taint
               Taint an SV. Use "SvTAINTED_on" instead.
                    void sv_taint(SV* sv)

       sv_tainted
               Test an SV for taintedness. Use "SvTAINTED"
               instead.       bool sv_tainted(SV* sv)

       sv_true Returns true if the SV has a true value by Perl's
               rules.  Use the "SvTRUE" macro instead, which may
               call "sv_true()" or may instead use an in-line
               version.

                       I32     sv_true(SV *sv)

       sv_unmagic
               Removes all magic of type "type" from an SV.

                       int     sv_unmagic(SV* sv, int type)

       sv_unref
               Unsets the RV status of the SV, and decrements the
               reference count of whatever was being referenced
               by the RV.  This can almost be thought of as a
               reversal of "newSVrv".  This is "sv_unref_flags"
               with the "flag" being zero.  See "SvROK_off".

                       void    sv_unref(SV* sv)

       sv_unref_flags
               Unsets the RV status of the SV, and decrements the
               reference count of whatever was being referenced
               by the RV.  This can almost be thought of as a
               Upgrade an SV to a more complex form.  Generally
               adds a new body type to the SV, then copies across
               as much information as possible from the old body.
               You generally want to use the "SvUPGRADE" macro
               wrapper. See also "svtype".

                       bool    sv_upgrade(SV* sv, U32 mt)

       sv_usepvn
               Tells an SV to use "ptr" to find its string value.
               Normally the string is stored inside the SV but
               sv_usepvn allows the SV to use an outside string.
               The "ptr" should point to memory that was allo­
               cated by "malloc".  The string length, "len", must
               be supplied.  This function will realloc the mem­
               ory pointed to by "ptr", so that pointer should
               not be freed or used by the programmer after giv­
               ing it to sv_usepvn.  Does not handle 'set' magic.
               See "sv_usepvn_mg".

                       void    sv_usepvn(SV* sv, char* ptr, STRLEN len)

       sv_usepvn_mg
               Like "sv_usepvn", but also handles 'set' magic.

                       void    sv_usepvn_mg(SV *sv, char *ptr, STRLEN len)

       sv_utf8_decode
               Convert the octets in the PV from UTF-8 to chars.
               Scan for validity and then turn off SvUTF8 if
               needed so that we see characters. Used as a build­
               ing block for decode_utf8 in Encode.xs

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

                       bool    sv_utf8_decode(SV *sv)

       sv_utf8_downgrade
               Attempt to convert the PV of an SV from
               UTF-8-encoded to byte encoding.  This may not be
               possible if the PV contains non-byte encoding
               characters; if this is the case, either returns
               false or, if "fail_ok" is not true, croaks.

               This is not as a general purpose Unicode to byte
               encoding interface: use the Encode extension for
               that.

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

               ity checks even if all the bytes have hibit clear.

               This is not as a general purpose byte encoding to
               Unicode interface: use the Encode extension for
               that.

                       STRLEN  sv_utf8_upgrade(SV *sv)

       sv_utf8_upgrade_flags
               Convert the PV of an SV to its UTF-8-encoded form.
               Forces the SV to string form if it is not already.
               Always sets the SvUTF8 flag to avoid future valid­
               ity checks even if all the bytes have hibit clear.
               If "flags" has "SV_GMAGIC" bit set, will "mg_get"
               on "sv" if appropriate, else not.
               "sv_utf8_upgrade" and "sv_utf8_upgrade_nomg" are
               implemented in terms of this function.

               This is not as a general purpose byte encoding to
               Unicode interface: use the Encode extension for
               that.

                       STRLEN  sv_utf8_upgrade_flags(SV *sv, I32 flags)

       sv_uv   A private implementation of the "SvUVx" macro for
               compilers which can't cope with complex macro
               expressions. Always use the macro instead.

                       UV      sv_uv(SV* sv)

       sv_vcatpvfn
               Processes its arguments like "vsprintf" and
               appends the formatted output to an SV.  Uses an
               array of SVs if the C style variable argument list
               is missing (NULL).  When running with taint checks
               enabled, indicates via "maybe_tainted" if results
               are untrustworthy (often due to the use of
               locales).

               Usually used via one of its frontends "sv_catpvf"
               and "sv_catpvf_mg".

                       void    sv_vcatpvfn(SV* sv, const char* pat, STRLEN patlen, va_list* args, SV** svargs, I32 svmax, bool *maybe_tainted)

       sv_vsetpvfn
               Works like "vcatpvfn" but copies the text into the
               SV instead of appending it.

               Usually used via one of its frontends "sv_setpvf"
               and "sv_setpvf_mg".

                       void    sv_vsetpvfn(SV* sv, const char* pat, STRLEN patlen, va_list* args, SV** svargs, I32 svmax, bool *maybe_tainted)

                       U8*     bytes_from_utf8(U8 *s, STRLEN *len, bool *is_utf8)

       bytes_to_utf8
               Converts a string "s" of length "len" from ASCII
               into UTF-8 encoding.  Returns a pointer to the
               newly-created string, and sets "len" to reflect
               the new length.

               If you want to convert to UTF-8 from other encod­
               ings than ASCII, see sv_recode_to_utf8().

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

                       U8*     bytes_to_utf8(U8 *s, STRLEN *len)

       ibcmp_utf8
               Return true if the strings s1 and s2 differ
               case-insensitively, false if not (if they are
               equal case-insensitively).  If u1 is true, the
               string s1 is assumed to be in UTF-8-encoded Uni­
               code.  If u2 is true, the string s2 is assumed to
               be in UTF-8-encoded Unicode.  If u1 or u2 are
               false, the respective string is assumed to be in
               native 8-bit encoding.

               If the pe1 and pe2 are non-NULL, the scanning
               pointers will be copied in there (they will point
               at the beginning of the next character).  If the
               pointers behind pe1 or pe2 are non-NULL, they are
               the end pointers beyond which scanning will not
               continue under any circustances.  If the byte
               lengths l1 and l2 are non-zero, s1+l1 and s2+l2
               will be used as goal end pointers that will also
               stop the scan, and which qualify towards defining
               a successful match: all the scans that define an
               explicit length must reach their goal pointers for
               a match to succeed).

               For case-insensitiveness, the "casefolding" of
               Unicode is used instead of upper/lowercasing both
               the characters, see http://www.unicode.org/uni­
               code/reports/tr21/ (Case Mappings).

                       I32     ibcmp_utf8(const char* a, char **pe1, UV l1, bool u1, const char* b, char **pe2, UV l2, bool u2)

       is_utf8_char
               Tests if some arbitrary number of bytes begins in
               a valid UTF-8 character.  Note that an INVARIANT
               (i.e. ASCII) character is a valid UTF-8 character.
               The actual number of bytes in the UTF-8 character

       is_utf8_string_loc
               Like is_ut8_string but store the location of the
               failure in the last argument.

                       bool    is_utf8_string_loc(U8 *s, STRLEN len, U8 **p)

       pv_uni_display
               Build to the scalar dsv a displayable version of
               the string spv, length len, the displayable ver­
               sion being at most pvlim bytes long (if longer,
               the rest is truncated and "..." will be appended).

               The flags argument can have UNI_DISPLAY_ISPRINT
               set to display isPRINT()able characters as them­
               selves, UNI_DISPLAY_BACKSLASH to display the
               \\[nrfta\\] as the backslashed versions (like
               '\n') (UNI_DISPLAY_BACKSLASH is preferred over
               UNI_DISPLAY_ISPRINT for \\).  UNI_DISPLAY_QQ (and
               its alias UNI_DISPLAY_REGEX) have both UNI_DIS­
               PLAY_BACKSLASH and UNI_DISPLAY_ISPRINT turned on.

               The pointer to the PV of the dsv is returned.

                       char*   pv_uni_display(SV *dsv, U8 *spv, STRLEN len, STRLEN pvlim, UV flags)

       sv_cat_decode
               The encoding is assumed to be an Encode object,
               the PV of the ssv is assumed to be octets in that
               encoding and decoding the input starts from the
               position which (PV + *offset) pointed to.  The dsv
               will be concatenated the decoded UTF-8 string from
               ssv.  Decoding will terminate when the string tstr
               appears in decoding output or the input ends on
               the PV of the ssv. The value which the offset
               points will be modified to the last input position
               on the ssv.

               Returns TRUE if the terminator was found, else
               returns FALSE.

                       bool    sv_cat_decode(SV* dsv, SV *encoding, SV *ssv, int *offset, char* tstr, int tlen)

       sv_recode_to_utf8
               The encoding is assumed to be an Encode object, on
               entry the PV of the sv is assumed to be octets in
               that encoding, and the sv will be converted into
               Unicode (and UTF-8).

               If the sv already is UTF-8 (or if it is not POK),
               or if the encoding is not a reference, nothing is
               done to the sv.  If the encoding is not an
               "Encode::XS" Encoding object, bad things will hap­
               The pointer to the PV of the dsv is returned.

                       char*   sv_uni_display(SV *dsv, SV *ssv, STRLEN pvlim, UV flags)

       to_utf8_case
               The "p" contains the pointer to the UTF-8 string
               encoding the character that is being converted.

               The "ustrp" is a pointer to the character buffer
               to put the conversion result to.  The "lenp" is a
               pointer to the length of the result.

               The "swashp" is a pointer to the swash to use.

               Both the special and normal mappings are stored
               lib/unicore/To/Foo.pl, and loaded by SWASHGET,
               using lib/utf8_heavy.pl.  The special (usually,
               but not always, a multicharacter mapping), is
               tried first.

               The "special" is a string like
               "utf8::ToSpecLower", which means the hash
               %utf8::ToSpecLower.  The access to the hash is
               through Perl_to_utf8_case().

               The "normal" is a string like "ToLower" which
               means the swash %utf8::ToLower.

                       UV      to_utf8_case(U8 *p, U8* ustrp, STRLEN *lenp, SV **swash, char *normal, char *special)

       to_utf8_fold
               Convert the UTF-8 encoded character at p to its
               foldcase version and store that in UTF-8 in ustrp
               and its length in bytes in lenp.  Note that the
               ustrp needs to be at least UTF8_MAXLEN_FOLD+1
               bytes since the foldcase version may be longer
               than the original character (up to three charac­
               ters).

               The first character of the foldcased version is
               returned (but note, as explained above, that there
               may be more.)

                       UV      to_utf8_fold(U8 *p, U8* ustrp, STRLEN *lenp)

       to_utf8_lower
               Convert the UTF-8 encoded character at p to its
               lowercase version and store that in UTF-8 in ustrp
               and its length in bytes in lenp.  Note that the
               ustrp needs to be at least UTF8_MAXLEN_UCLC+1
               bytes since the lowercase version may be longer
               than the original character (up to two charac­
               than the original character (up to two charac­
               ters).

               The first character of the titlecased version is
               returned (but note, as explained above, that there
               may be more.)

                       UV      to_utf8_title(U8 *p, U8* ustrp, STRLEN *lenp)

       to_utf8_upper
               Convert the UTF-8 encoded character at p to its
               uppercase version and store that in UTF-8 in ustrp
               and its length in bytes in lenp.  Note that the
               ustrp needs to be at least UTF8_MAXLEN_UCLC+1
               bytes since the uppercase version may be longer
               than the original character (up to two charac­
               ters).

               The first character of the uppercased version is
               returned (but note, as explained above, that there
               may be more.)

                       UV      to_utf8_upper(U8 *p, U8* ustrp, STRLEN *lenp)

       utf8n_to_uvchr
               Returns the native character value of the first
               character in the string "s" which is assumed to be
               in UTF-8 encoding; "retlen" will be set to the
               length, in bytes, of that character.

               Allows length and flags to be passed to low level
               routine.

                       UV      utf8n_to_uvchr(U8 *s, STRLEN curlen, STRLEN* retlen, U32 flags)

       utf8n_to_uvuni
               Bottom level UTF-8 decode routine.  Returns the
               unicode code point value of the first character in
               the string "s" which is assumed to be in UTF-8
               encoding and no longer than "curlen"; "retlen"
               will be set to the length, in bytes, of that char­
               acter.

               If "s" does not point to a well-formed UTF-8 char­
               acter, the behaviour is dependent on the value of
               "flags": if it contains UTF8_CHECK_ONLY, it is
               assumed that the caller will raise a warning, and
               this function will silently just set "retlen" to
               "-1" and return zero.  If the "flags" does not
               contain UTF8_CHECK_ONLY, warnings about malforma­
               tions will be given, "retlen" will be set to the
               expected length of the UTF-8 character in bytes,

               WARNING: use only if you *know* that the pointers
               point inside the same UTF-8 buffer.

                       IV      utf8_distance(U8 *a, U8 *b)

       utf8_hop
               Return the UTF-8 pointer "s" displaced by "off"
               characters, either forward or backward.

               WARNING: do not use the following unless you
               *know* "off" is within the UTF-8 data pointed to
               by "s" *and* that on entry "s" is aligned on the
               first byte of character or just after the last
               byte of a character.

                       U8*     utf8_hop(U8 *s, I32 off)

       utf8_length
               Return the length of the UTF-8 char encoded string
               "s" in characters.  Stops at "e" (inclusive).  If
               "e < s" or if the scan would end up past "e",
               croaks.

                       STRLEN  utf8_length(U8* s, U8 *e)

       utf8_to_bytes
               Converts a string "s" of length "len" from UTF-8
               into byte encoding.  Unlike "bytes_to_utf8", this
               over-writes the original string, and updates len
               to contain the new length.  Returns zero on fail­
               ure, setting "len" to -1.

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

                       U8*     utf8_to_bytes(U8 *s, STRLEN *len)

       utf8_to_uvchr
               Returns the native character value of the first
               character in the string "s" which is assumed to be
               in UTF-8 encoding; "retlen" will be set to the
               length, in bytes, of that character.

               If "s" does not point to a well-formed UTF-8 char­
               acter, zero is returned and retlen is set, if pos­
               sible, to -1.

                       UV      utf8_to_uvchr(U8 *s, STRLEN* retlen)

       utf8_to_uvuni
               Returns the Unicode code point of the first char­

       uvchr_to_utf8
               Adds the UTF-8 representation of the Native code­
               point "uv" to the end of the string "d"; "d"
               should be have at least "UTF8_MAXLEN+1" free bytes
               available. The return value is the pointer to the
               byte after the end of the new character. In other
               words,

                   d = uvchr_to_utf8(d, uv);

               is the recommended wide native character-aware way
               of saying

                   *(d++) = uv;

                       U8*     uvchr_to_utf8(U8 *d, UV uv)

       uvuni_to_utf8_flags
               Adds the UTF-8 representation of the Unicode code­
               point "uv" to the end of the string "d"; "d"
               should be have at least "UTF8_MAXLEN+1" free bytes
               available. The return value is the pointer to the
               byte after the end of the new character. In other
               words,

                   d = uvuni_to_utf8_flags(d, uv, flags);

               or, in most cases,

                   d = uvuni_to_utf8(d, uv);

               (which is equivalent to)

                   d = uvuni_to_utf8_flags(d, uv, 0);

               is the recommended Unicode-aware way of saying

                   *(d++) = uv;

                       U8*     uvuni_to_utf8_flags(U8 *d, UV uv, UV flags)


Variables created by "xsubpp" and "xsubpp" internal functions

       ax      Variable which is setup by "xsubpp" to indicate
               the stack base offset, used by the "ST", "XSpre­
               PUSH" and "XSRETURN" macros.  The "dMARK" macro
               must be called prior to setup the "MARK" variable.

                       I32     ax

       CLASS   Variable which is setup by "xsubpp" to indicate
               the class name for a C++ XS constructor.  This is
               always a "char*".  See "THIS".

       dXSARGS Sets up stack and mark pointers for an XSUB, call­
               ing dSP and dMARK.  Sets up the "ax" and "items"
               variables by calling "dAX" and "dITEMS".  This is
               usually handled automatically by "xsubpp".

                               dXSARGS;

       dXSI32  Sets up the "ix" variable for an XSUB which has
               aliases.  This is usually handled automatically by
               "xsubpp".

                               dXSI32;

       items   Variable which is setup by "xsubpp" to indicate
               the number of items on the stack.  See "Vari­
               able-length Parameter Lists" in perlxs.

                       I32     items

       ix      Variable which is setup by "xsubpp" to indicate
               which of an XSUB's aliases was used to invoke it.
               See "The ALIAS: Keyword" in perlxs.

                       I32     ix

       newXSproto
               Used by "xsubpp" to hook up XSUBs as Perl subs.
               Adds Perl prototypes to the subs.

       RETVAL  Variable which is setup by "xsubpp" to hold the
               return value for an XSUB. This is always the
               proper type for the XSUB. See "The RETVAL Vari­
               able" in perlxs.

                       (whatever)      RETVAL

       ST      Used to access elements on the XSUB's stack.

                       SV*     ST(int ix)

       THIS    Variable which is setup by "xsubpp" to designate
               the object in a C++ XSUB.  This is always the
               proper type for the C++ object.  See "CLASS" and
               "Using XS With C++" in perlxs.

                       (whatever)      THIS

       XS      Macro to declare an XSUB and its C parameter list.
               This is handled by "xsubpp".

       XSRETURN_EMPTY
               "xsubpp".  See "The VERSIONCHECK: Keyword" in per­
               lxs.

                               XS_VERSION_BOOTCHECK;


Warning and Dieing

       croak   This is the XSUB-writer's interface to Perl's
               "die" function.  Normally use this function the
               same way you use the C "printf" function.  See
               "warn".

               If you want to throw an exception object, assign
               the object to $@ and then pass "Nullch" to
               croak():

                  errsv = get_sv("@", TRUE);
                  sv_setsv(errsv, exception_object);
                  croak(Nullch);

                       void    croak(const char* pat, ...)

       warn    This is the XSUB-writer's interface to Perl's
               "warn" function.  Use this function the same way
               you use the C "printf" function.  See "croak".

                       void    warn(const char* pat, ...)


AUTHORS

       Until May 1997, this document was maintained by Jeff
       Okamoto <okamoto@corp.hp.com>.  It is now maintained as
       part of Perl itself.

       With lots of help and suggestions from Dean Roehrich, Mal­
       colm Beattie, Andreas Koenig, Paul Hudson, Ilya Zakhare­
       vich, Paul Marquess, Neil Bowers, Matthew Green, Tim
       Bunce, Spider Boardman, Ulrich Pfeifer, Stephen McCamant,
       and Gurusamy Sarathy.

       API Listing originally by Dean Roehrich
       <roehrich@cray.com>.

       Updated to be autogenerated from comments in the source by
       Benjamin Stuhl.


SEE ALSO

       perlguts(1), perlxs(1), perlxstut(1), perlintern(1)

perl v5.8.1                 2003-09-02                 PERLAPI(1)

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