perlapi



PERLAPI(1)             Perl Programmers Reference Guide             PERLAPI(1)




NAME

       perlapi - autogenerated documentation for the perl public API


DESCRIPTION

       This file contains the documentation of the perl public API generated
       by embed.pl, specifically a listing of functions, 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 compatibility with the
       older, unadorned names, but this support 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 "wantarray".  Returns
               "G_VOID", "G_SCALAR" or "G_ARRAY" for void, scalar or list con-
               text, 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 callback.  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 Manipulation Functions

       AvFILL  Same as "av_len()".  Deprecated, use "av_len()" instead.

                       int     AvFILL(AV* av)

       av_clear
               Clears an array, making it empty.  Does not free the memory
               used by the array itself.

                       void    av_clear(AV* ar)

       av_delete
               Deletes the element indexed by "key" from the array.  Returns
               the deleted element. If "flags" equals "G_DISCARD", the element
               is freed and null is returned.

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

       av_exists
               Returns true if the element indexed by "key" has been initial-
               ized.

               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 deref-
               erencing 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 elements, 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.

                       SV*     av_pop(AV* ar)

       av_push Pushes an SV onto the end of the array.  The array will grow
               automatically to accommodate the addition.

                       void    av_push(AV* ar, SV* val)

       av_shift
               Shifts an SV off the beginning of the array.

                       SV*     av_shift(AV* ar)

       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 incrementing 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 deprecated.

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

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

                       AV*     newAV()

       sortsv  Sort an array. Here is an example:

                   sortsv(AvARRAY(av), av_len(av)+1, Perl_sv_cmp_locale);

               See lib/sort.pm for details about controlling the sorting algo-
               rithm.

                       void    sortsv(SV ** array, size_t num_elts, SVCOMPARE_t cmp)


Callback Functions

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

               NOTE: the perl_ form of this function is deprecated.

                       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 deprecated.

                       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 deprecated.

                       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 deprecated.

                       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 deprecated.

                       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 deprecated.

                       I32     eval_sv(SV* sv, I32 flags)

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

                               FREETMPS;

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

                               LEAVE;

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

                               SAVETMPS;


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 lower-
               case character.

                       bool    isLOWER(char ch)

       isSPACE Returns a boolean indicating whether the C "char" is whites-
               pace.

                       bool    isSPACE(char ch)

       isUPPER Returns a boolean indicating whether the C "char" is an upper-
               case 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-fork
               code uses COPY_STACKS while the threads->new doesn’t.

               CLONEf_KEEP_PTR_TABLE perl_clone keeps a ptr_table with the
               pointer of the old variable as a key and the new variable as a
               value, this allows it to check if something has been cloned and
               not clone it again but rather just use the value and increase
               the refcount. If KEEP_PTR_TABLE is not set then perl_clone will
               kill the ptr_table using the function "ptr_ta-
               ble_free(PL_ptr_table); PL_ptr_table = NULL;", reason to keep
               it around is if you want to dup some of your own variable who
               are outside the graph perl scans, example of this 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 separate 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 deprecated.

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


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 former 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 speci-
               fied, provides version semantics similar to "use Foo::Bar VER-
               SION".  The optional trailing SV* arguments can be used to
               specify arguments to the module’s import() method, similar to
               "use Foo::Bar VERSION LIST".

                       void    load_module(U32 flags, SV* name, SV* ver, ...)

       nothreadhook
               Stub that provides thread hook for perl_destruct when there are
               no threads.

                       int     nothreadhook()

       perl_alloc
               Allocates a new Perl interpreter.  See perlembed.

                       PerlInterpreter*        perl_alloc()

       perl_construct
               Initializes a new Perl interpreter.  See perlembed.

                       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 perlem-
               bed.

                       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 deprecated.

                       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.

                       void    pack_cat(SV *cat, char *pat, char *patend, SV **beglist, SV **endlist, SV ***next_in_list, U32 flags)

       unpackstring
               The engine implementing unpack() Perl function. "unpackstring"
               puts the extracted list items on the stack and returns the num-
               ber of elements.  Issue "PUTBACK" before and "SPAGAIN" after
               the call to this function.

                       I32     unpackstring(char *pat, char *patend, char *s, char *strend, U32 flags)

       unpack_str
               The engine implementing unpack() Perl function. Note: parame-
               ters strbeg, new_s and ocnt are not used. This call should not
               be used, use unpackstring 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-inter-
               preter basis.  In a pinch, it can also be used as a symbol ta-
               ble 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 "level==0",
               as a side-effect creates a glob with the given "name" in the
               given "stash" which in the case of success contains an alias
               for the subroutine, and sets up caching info for this glob.
               Similarly for all the searched stashes.

               This function grants "SUPER" token as a postfix of the stash
               name. The GV returned from "gv_fetchmeth" may be a method cache
               entry, which is not visible to Perl code.  So when calling
               "call_sv", you should not use the GV directly; instead, you
               should use the method’s CV, which can be obtained from the GV
               with the "GvCV" macro.

                       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 corresponding 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_fetch-
               meth" 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 subroutine.

               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 package.  "name"
               should be a valid UTF-8 string.  If "create" is set then the
               package will be created if it does not already exist.  If "cre-
               ate" is not set and the package does not exist then NULL is
               returned.

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

       gv_stashsv
               Returns a pointer to the stash for a specified package, which
               must be a valid UTF-8 string.  See "gv_stashpv".

                       HV*     gv_stashsv(SV* sv, I32 create)


Handy Values

       Nullav  Null AV pointer.

       Nullch  Null character pointer.

       Nullcv  Null CV pointer.

       Nullhv  Null HV 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 deprecated.

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

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

       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.  Otherwise, holds the actual
               length of the key.  Can be assigned to. The "HePV()" macro is
               usually preferable 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 of the
               key is, you may use the global variable "PL_na", though this is
               rather less efficient than using a local variable.  Remember
               though, that hash keys in perl are free to contain embedded
               nulls, so using "strlen()" or similar is not a good way to find
               the length of hash keys. This is very similar to the "SvPV()"
               macro described elsewhere in this document.

                       char*   HePV(HE* he, STRLEN len)

       HeSVKEY Returns the key as an "SV*", or "Nullsv" if the hash entry does
               not contain an "SV*" key.

                       SV*     HeSVKEY(HE* he)

       HeSVKEY_force
               Returns the key as an "SV*".  Will create and return a tempo-
               rary 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 appropri-
               ate 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 "SvSTASH", "CvSTASH".

                       char*   HvNAME(HV* stash)

       hv_clear
               Clears a hash, making it empty.

                       void    hv_clear(HV* tb)

       hv_clear_placeholders
               Clears any placeholders from a hash.  If a restricted hash has
               any of its keys marked as readonly and the key is subsequently
               deleted, the key is not actually deleted but is marked by
               assigning it a value of &PL_sv_placeholder.  This tags it so it
               will be ignored by future operations such as iterating over the
               hash, but will still allow the hash to have a value reassigned
               to the key at some future point.  This function clears any such
               placeholder keys from the hash.  See Hash::Util::lock_keys()
               for an example of its use.

                       void    hv_clear_placeholders(HV* hb)

       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 hash key
               exists.  The "klen" is the length of the key.

                       bool    hv_exists(HV* tb, const char* key, I32 klen)

       hv_exists_ent
               Returns a boolean indicating whether the specified hash key
               exists. "hash" can be a valid precomputed hash value, or 0 to
               ask for it to be computed.

                       bool    hv_exists_ent(HV* tb, SV* key, U32 hash)

       hv_fetch
               Returns the SV which corresponds to 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 with-
               out 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 position of the
               hash iterator.  The return value will always be a mortal copy
               of the key.  Also see "hv_iterinit".

                       SV*     hv_iterkeysv(HE* entry)

       hv_iternext
               Returns entries from a hash iterator.  See "hv_iterinit".

               You may call "hv_delete" or "hv_delete_ent" on the hash entry
               that the iterator currently points to, without losing your
               place or invalidating your iterator.  Note that in this case
               the current 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 iterator immediately else the entry will leak
               - call "hv_iternext" to trigger the resource deallocation.

                       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_WANTPLACEHOLDERS is set the placeholders keys (for
               restricted hashes) will be returned in addition to normal keys.
               By default placeholders are automatically skipped over.  Cur-
               rently a placeholder is implemented with a value that is
               &Perl_sv_placeholder. Note that the implementation of place-
               holders and restricted hashes may change, and the implementa-
               tion 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 itera-
               tor.  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_scalar
               Evaluates the hash in scalar context and returns the result.
               Handles magic when the hash is tied.

                       SV*     hv_scalar(HV* hv)

       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 the value did not need to be actually stored within the hash
               (as in the case of tied hashes).  Otherwise it can be derefer-
               enced to get the original "SV*".  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 takes owner-
               ship 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.  hv_store is
               not implemented 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 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.

                       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 reference 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 temporary 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)

       newHV   Creates a new HV.  The reference count is set to 1.

                       HV*     newHV()


Magical Functions

       mg_clear
               Clear something magical that the SV represents.  See
               "sv_magic".

                       int     mg_clear(SV* sv)

       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.

                       void    SvSETMAGIC(SV* sv)

       SvSetMagicSV
               Like "SvSetSV", but does any set magic required afterwards.

                       void    SvSetMagicSV(SV* dsb, SV* ssv)

       SvSetMagicSV_nosteal
               Like "SvSetSV_nosteal", but does any set magic required after-
               wards.

                       void    SvSetMagicSV_nosteal(SV* dsv, SV* ssv)

       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 mod-
               ule has been loaded.

                       void    SvSHARE(SV* sv)

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

                       void    SvUNLOCK(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 overlap-
               ping copies.  See also "Move".

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

       CopyD   Like "Copy" but returns dest. Useful for encouraging compilers
               to tail-call optimise.

                       void *  CopyD(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)

       MoveD   Like "Move" but returns dest. Useful for encouraging compilers
               to tail-call optimise.

                       void *  MoveD(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)

       Newz    The XSUB-writer’s interface to the C "malloc" function.  The
               allocated memory is zeroed with "memzero".

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

       Poison  Fill up memory with a pattern (byte 0xAB over and over again)
               that hopefully catches attempts to access uninitialized memory.

                       void    Poison(void* dest, int nitems, type)

       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" function.

                       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()" function.

                       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 dupli-
               cate of the first "len" bytes from "pv". The memory allocated
               for the new string can be freed with the "Safefree()" function.

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

       savesharedpv
               A version of "savepv()" which allocates the duplicate 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.

                       void    Zero(void* dest, int nitems, type)

       ZeroD   Like "Zero" but returns dest. Useful for encouraging compilers
               to tail-call optimise.

                       void *  ZeroD(void* dest, int nitems, type)


Miscellaneous Functions

       fbm_compile
               Analyses the string in order to make fast searches on it using
               fbm_instr() -- the Boyer-Moore algorithm.

                       void    fbm_compile(SV* sv, U32 flags)

       fbm_instr
               Returns the location of the SV in the string delimited by "str"
               and "strend".  It returns "Nullch" if the string can’t be
               found.  The "sv" 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 conventional (non-SV)
               arguments and returns the formatted 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 less than the
               second, "s2".  Returns true or false.

                       bool    strLT(char* s1, char* s2)

       strNE   Test two strings to see if they are different.  Returns true or
               false.

                       bool    strNE(char* s1, char* s2)

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

                       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 mod-
               ule 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 character.  Unless "PERL_SCAN_SILENT_ILLDIGIT" is set
               in *flags, encountering an invalid character will also trigger
               a warning.  On return *len is set to the length of the 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 value is discarded if result is
               NULL).

               The binary number may optionally be prefixed with "0b" or "b"
               unless "PERL_SCAN_DISALLOW_PREFIX" is set in *flags on entry.
               If "PERL_SCAN_ALLOW_UNDERSCORES" is set in *flags then the
               binary number may use ’_’ characters to separate digits.

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

       grok_hex
               converts a string representing a hex 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 character.  Unless "PERL_SCAN_SILENT_ILLDIGIT" is set
               in *flags, encountering an invalid character will also trigger
               a warning.  On return *len is set to the length of the 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_UNDERSCORES" 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 number is
               returned (0 if unrecognised), otherwise it is a bit-ORed combi-
               nation of IS_NUMBER_IN_UV, IS_NUMBER_GREATER_THAN_UV_MAX,
               IS_NUMBER_NOT_INT, IS_NUMBER_NEG, IS_NUMBER_INFINITY, IS_NUM-
               BER_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 *val-
               uep is valid, IS_NUMBER_IN_UV will never be set unless *valuep
               is valid, but *valuep may have been assigned to during process-
               ing even though IS_NUMBER_IN_UV is not set on return.  If val-
               uep 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 integer), 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)

       grok_numeric_radix
               Scan and skip for a numeric decimal separator (radix).

                       bool    grok_numeric_radix(const char **sp, const char *send)

       grok_oct
               converts a string representing an octal 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 character.  Unless "PERL_SCAN_SILENT_ILLDIGIT" is set
               in *flags, encountering an invalid character will also trigger
               a warning.  On return *len is set to the length of the 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_oct" 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).

               If "PERL_SCAN_ALLOW_UNDERSCORES" is set in *flags then the
               octal number may use ’_’ characters to separate digits.

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

       scan_bin
               For backwards compatibility. Use "grok_bin" instead.

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

       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 compile-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;

       dSP     Declares a local copy of perl’s stack pointer for the XSUB,
               available via the "SP" macro.  See "SP".

                               dSP;

       EXTEND  Used to extend the argument stack for an XSUB’s return values.
               Once used, guarantees that there is room for at least "nitems"
               to be pushed onto the stack.

                       void    EXTEND(SP, int nitems)

       MARK    Stack marker variable for the XSUB.  See "dMARK".

       mPUSHi  Push an integer onto the stack.  The stack must have room for
               this element.  Handles ’set’ magic.  Does not use "TARG".  See
               also "PUSHi", "mXPUSHi" and "XPUSHi".

                       void    mPUSHi(IV iv)

       mPUSHn  Push a double onto the stack.  The stack must have room for
               this element.  Handles ’set’ magic.  Does not use "TARG".  See
               also "PUSHn", "mXPUSHn" and "XPUSHn".

                       void    mPUSHn(NV nv)

       mPUSHp  Push a string onto the stack.  The stack must have room for
               this element.  The "len" indicates the length of the string.
               Handles ’set’ magic.  Does not use "TARG".  See also "PUSHp",
               "mXPUSHp" and "XPUSHp".

                       void    mPUSHp(char* str, STRLEN len)

       mPUSHu  Push an unsigned integer onto the stack.  The stack must have
               room for this element.  Handles ’set’ magic.  Does not use
               "TARG".  See also "PUSHu", "mXPUSHu" and "XPUSHu".

                       void    mPUSHu(UV uv)

       mXPUSHi Push an integer onto the stack, extending the stack if neces-
               sary.  Handles ’set’ magic.  Does not use "TARG".  See also
               "XPUSHi", "mPUSHi" and "PUSHi".

                       void    mXPUSHi(IV iv)

       mXPUSHn Push a double onto the stack, extending the stack if necessary.
               Handles ’set’ magic.  Does not use "TARG".  See also "XPUSHn",
               "mPUSHn" and "PUSHn".

                       void    mXPUSHn(NV nv)

       mXPUSHp Push a string onto the stack, extending the stack if necessary.
               The "len" indicates the length of the string.  Handles ’set’
               magic.  Does not use "TARG".  See also "XPUSHp", "mPUSHp" and
               "PUSHp".

                       void    mXPUSHp(char* str, STRLEN len)

       mXPUSHu Push an unsigned integer onto the stack, extending the stack if
               necessary.  Handles ’set’ magic.  Does not use "TARG".  See
               also "XPUSHu", "mPUSHu" and "PUSHu".

                       void    mXPUSHu(UV uv)

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

       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 pro-
               vide 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.  Uses "TARG", so "dTARGET"
               or "dXSTARG" should be called to declare it.  Do not call mul-
               tiple "TARG"-oriented macros to return lists from XSUB’s - see
               "mPUSHi" instead.  See also "XPUSHi" and "mXPUSHi".

                       void    PUSHi(IV iv)

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

                       void    PUSHMARK(SP)

       PUSHmortal
               Push a new mortal SV onto the stack.  The stack must have room
               for this element.  Does not handle ’set’ magic.  Does not use
               "TARG".  See also "PUSHs", "XPUSHmortal" and "XPUSHs".

                       void    PUSHmortal()

       PUSHn   Push a double onto the stack.  The stack must have room for
               this element.  Handles ’set’ magic.  Uses "TARG", so "dTARGET"
               or "dXSTARG" should be called to declare it.  Do not call mul-
               tiple "TARG"-oriented macros to return lists from XSUB’s - see
               "mPUSHn" instead.  See also "XPUSHn" and "mXPUSHn".

                       void    PUSHn(NV nv)

       PUSHp   Push a string onto the stack.  The stack must have room for
               this element.  The "len" indicates the length of the string.
               Handles ’set’ magic.  Uses "TARG", so "dTARGET" or "dXSTARG"
               should be called to declare it.  Do not call multiple
               "TARG"-oriented macros to return lists from XSUB’s - see
               "mPUSHp" instead.  See also "XPUSHp" and "mXPUSHp".

                       void    PUSHp(char* str, STRLEN len)

       PUSHs   Push an SV onto the stack.  The stack must have room for this
               element.  Does not handle ’set’ magic.  Does not use "TARG".
               See also "PUSHmortal", "XPUSHs" and "XPUSHmortal".

                       void    PUSHs(SV* sv)

       PUSHu   Push an unsigned integer onto the stack.  The stack must have
               room for this element.  Handles ’set’ magic.  Uses "TARG", so
               "dTARGET" or "dXSTARG" should be called to declare it.  Do not
               call multiple "TARG"-oriented macros to return lists from
               XSUB’s - see "mPUSHu" instead.  See also "XPUSHu" and
               "mXPUSHu".

                       void    PUSHu(UV uv)

       PUTBACK Closing bracket for XSUB arguments.  This is usually 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 perl-
               call.

                               SPAGAIN;

       XPUSHi  Push an integer onto the stack, extending the stack if neces-
               sary.  Handles ’set’ magic.  Uses "TARG", so "dTARGET" or "dXS-
               TARG" should be called to declare it.  Do not call multiple
               "TARG"-oriented macros to return lists from XSUB’s - see
               "mXPUSHi" instead.  See also "PUSHi" and "mPUSHi".

                       void    XPUSHi(IV iv)

       XPUSHmortal
               Push a new mortal SV onto the stack, extending the stack if
               necessary.  Does not handle ’set’ magic.  Does not use "TARG".
               See also "XPUSHs", "PUSHmortal" and "PUSHs".

                       void    XPUSHmortal()

       XPUSHn  Push a double onto the stack, extending the stack if necessary.
               Handles ’set’ magic.  Uses "TARG", so "dTARGET" or "dXSTARG"
               should be called to declare it.  Do not call multiple
               "TARG"-oriented macros to return lists from XSUB’s - see
               "mXPUSHn" instead.  See also "PUSHn" and "mPUSHn".

                       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.  Uses "TARG", so "dTARGET" or "dXSTARG" should be called
               to declare it.  Do not call multiple "TARG"-oriented macros to
               return lists from XSUB’s - see "mXPUSHp" instead.  See also
               "PUSHp" and "mPUSHp".

                       void    XPUSHp(char* str, STRLEN len)

       XPUSHs  Push an SV onto the stack, extending the stack if necessary.
               Does not handle ’set’ magic.  Does not use "TARG".  See also
               "XPUSHmortal", "PUSHs" and "PUSHmortal".

                       void    XPUSHs(SV* sv)

       XPUSHu  Push an unsigned integer onto the stack, extending the stack if
               necessary.  Handles ’set’ magic.  Uses "TARG", so "dTARGET" or
               "dXSTARG" should be called to declare it.  Do not call multiple
               "TARG"-oriented macros to return lists from XSUB’s - see
               "mXPUSHu" instead.  See also "PUSHu" and "mPUSHu".

                       void    XPUSHu(UV uv)

       XSRETURN
               Return from XSUB, indicating number of items on the stack.
               This is usually handled by "xsubpp".

                       void    XSRETURN(int nitems)

       XSRETURN_EMPTY
               Return an empty list from an XSUB immediately.

                               XSRETURN_EMPTY;

       XSRETURN_IV
               Return an integer from an XSUB immediately.  Uses "XST_mIV".

                       void    XSRETURN_IV(IV iv)

       XSRETURN_NO
               Return &PL_sv_no from an XSUB immediately.  Uses "XST_mNO".

                               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 immediately.  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 position "pos" on
               the stack.  The value is stored in a new mortal SV.

                       void    XST_mPV(int pos, char* str)

       XST_mUNDEF
               Place &PL_sv_undef into the specified position "pos" on the
               stack.

                       void    XST_mUNDEF(int pos)

       XST_mYES
               Place &PL_sv_yes into the specified position "pos" on the
               stack.

                       void    XST_mYES(int pos)


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 cre-
               ated.  If "create" is not set and the variable does not exist
               then NULL is returned.

               NOTE: the perl_ form of this function is deprecated.

                       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 num-
               ber).  "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
               Creates an RV wrapper for an SV.  The reference count for the
               original SV is not incremented.

                       SV*     newRV_noinc(SV *sv)

       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 allo-
               cated.)  The reference count for the new SV is set to 1.  "id"
               is an integer id between 0 and 1299 (used to identify leaks).

                       SV*     NEWSV(int id, STRLEN len)

       newSV   Create a new null SV, or if len > 0, create a new empty SVt_PV
               type SV with an initial PV allocation of len+1. Normally
               accessed via the "NEWSV" macro.

                       SV*     newSV(STRLEN len)

       newSViv Creates a new SV and copies an integer into it.  The reference
               count for the SV is set to 1.

                       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 com-
               pute 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.
               If the "s" argument is NULL the new SV will be undefined.

                       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)

       newSVsv Creates a new SV which is an exact duplicate of the original
               SV.  (Uses "sv_setsv").

                       SV*     newSVsv(SV* old)

       newSVuv Creates a new SV and copies an unsigned integer into it.  The
               reference count for the SV is set to 1.

                       SV*     newSVuv(UV u)

       SvCUR   Returns the length of the string which is in the SV.  See
               "SvLEN".

                       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 (remember to reserve space for an
               extra trailing NUL character).  Calls "sv_grow" to perform the
               expansion if necessary.  Returns a pointer to the character
               buffer.

                       char *  SvGROW(SV* sv, STRLEN len)

       SvIOK   Returns a boolean indicating whether the SV contains an inte-
               ger.

                       bool    SvIOK(SV* sv)

       SvIOKp  Returns a boolean indicating whether the SV contains an inte-
               ger.  Checks the private setting.  Use "SvIOK".

                       bool    SvIOKp(SV* sv)

       SvIOK_notUV
               Returns a boolean indicating whether the SV contains a signed
               integer.

                       bool    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
               Tells an SV that it is an integer and disables all other OK
               bits.

                       void    SvIOK_only(SV* sv)

       SvIOK_only_UV
               Tells and SV that it is an unsigned integer and disables all
               other OK bits.

                       void    SvIOK_only_UV(SV* sv)

       SvIOK_UV
               Returns a boolean indicating whether the SV contains an
               unsigned integer.

                       bool    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   Coerces the given SV to an integer and returns it. Guarantees
               to evaluate sv only once. Use the more efficient "SvIV" other-
               wise.

                       IV      SvIVx(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)

       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 contains a number,
               integer or double.

                       bool    SvNIOK(SV* sv)

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

                       bool    SvNIOKp(SV* sv)

       SvNIOK_off
               Unsets the NV/IV status of an SV.

                       void    SvNIOK_off(SV* sv)

       SvNOK   Returns a boolean indicating whether the SV contains a double.

                       bool    SvNOK(SV* sv)

       SvNOKp  Returns a boolean indicating whether the SV contains a double.
               Checks the private setting.  Use "SvNOK".

                       bool    SvNOKp(SV* sv)

       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. It
               also tells whether the value is defined or not.

                       bool    SvOK(SV* sv)

       SvOOK   Returns a boolean indicating whether the SvIVX is a valid off-
               set 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 contains a charac-
               ter string.

                       bool    SvPOK(SV* sv)

       SvPOKp  Returns a boolean indicating whether the SV contains a charac-
               ter string.  Checks the private setting.  Use "SvPOK".

                       bool    SvPOKp(SV* sv)

       SvPOK_off
               Unsets the PV status of an SV.

                       void    SvPOK_off(SV* sv)

       SvPOK_on
               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 status.

                       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 contain a string.  The SV may
               cache the stringified version becoming "SvPOK".  Handles ’get’
               magic. See also "SvPVx" for a version which guarantees to eval-
               uate sv only once.

                       char*   SvPV(SV* sv, STRLEN len)

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

                       char*   SvPVbyte(SV* sv, STRLEN len)

       SvPVbytex
               Like "SvPV", but converts sv to byte representation 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 representation first
               if necessary.  Guarantees to evaluate 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 representation first
               if necessary.

                       char*   SvPVbyte_force(SV* sv, STRLEN len)

       SvPVbyte_nolen
               Like "SvPV_nolen", but converts sv to byte representation first
               if necessary.

                       char*   SvPVbyte_nolen(SV* sv)

       SvPVutf8
               Like "SvPV", but converts sv to utf8 first if necessary.

                       char*   SvPVutf8(SV* sv, STRLEN len)

       SvPVutf8x
               Like "SvPV", but converts sv to utf8 first if necessary.  Guar-
               antees 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" otherwise.

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

                       char*   SvPVx(SV* sv, STRLEN len)

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

                       char*   SvPVX(SV* sv)

       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)

       SvPV_nolen
               Returns a pointer to the string in the SV, or a stringified
               form of the SV if the SV does not contain a string.  The SV may
               cache the stringified form becoming "SvPOK".  Handles ’get’
               magic.

                       char*   SvPV_nolen(SV* sv)

       SvREFCNT
               Returns the value of the object’s reference count.

                       U32     SvREFCNT(SV* sv)

       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 mod-
               ule 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 fash-
               ion, via a carefully crafted regexp, rather than directly
               untainting variables.

                       void    SvTAINTED_off(SV* sv)

       SvTAINTED_on
               Marks an SV as tainted if tainting is enabled.

                       void    SvTAINTED_on(SV* sv)

       SvTRUE  Returns a boolean indicating whether Perl would evaluate the SV
               as true or false, defined or undefined.  Does not handle ’get’
               magic.

                       bool    SvTRUE(SV* sv)

       SvTYPE  Returns the type of the SV.  See "svtype".

                       svtype  SvTYPE(SV* sv)

       SvUOK   Returns a boolean indicating whether the SV contains 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 necessary.  See
               "svtype".

                       void    SvUPGRADE(SV* sv, svtype type)

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

                       bool    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 guarantees to evaluate sv only
               once.

                       UV      SvUV(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.

                       UV      SvUVx(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)

       sv_2bool
               This function is only called on magical items, and is only used
               by sv_true() or its macro equivalent.

                       bool    sv_2bool(SV* sv)

       sv_2cv  Using various gambits, try to get a CV from an SV; in addition,
               try if possible to set *st and *gvp to the stash and GV
               associated with it.

                       CV*     sv_2cv(SV* sv, HV** st, GV** gvp, I32 lref)

       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 symbol 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 necessary 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.  SvTEMP()
               is turned on which means that the SV’s string buffer can be
               "stolen" if this SV is copied. 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 representation 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 representation 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 representation of the SV,
               and set *lp to its length.  May cause the SV to be upgraded to
               UTF-8 as a side-effect.

               Usually accessed via the "SvPVutf8" macro.

                       char*   sv_2pvutf8(SV* sv, STRLEN* lp)

       sv_2pvutf8_nolen
               Return a pointer to the UTF-8-encoded representation of the SV.
               May cause the SV to be upgraded to UTF-8 as a side-effect.

               Usually accessed via the "SvPVutf8_nolen" macro.

                       char*   sv_2pvutf8_nolen(SV* sv)

       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" usu-
               ally 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. Normally 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 status 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 format-
               ted output to an SV.  If the appended data contains "wide"
               characters (including, but not limited to, SVs with a UTF-8 PV
               formatted with %s, and characters >255 formatted with %c), the
               original SV might get upgraded to UTF-8.  Handles ’get’ magic,
               but not ’set’ magic.  See "sv_catpvf_mg".

                       void    sv_catpvf(SV* sv, const char* pat, ...)

       sv_catpvf_mg
               Like "sv_catpvf", but also handles ’set’ magic.

                       void    sv_catpvf_mg(SV *sv, const char* pat, ...)

       sv_catpvn
               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_cat-
               pvn_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_catpvn_nomg
               Like "sv_catpvn" but doesn’t process magic.

                       void    sv_catpvn_nomg(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 appropri-
               ate, 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.

                       void    sv_catsv_mg(SV *dstr, SV *sstr)

       sv_catsv_nomg
               Like "sv_catsv" but doesn’t process magic.

                       void    sv_catsv_nomg(SV* dsv, SV* ssv)

       sv_chop Efficient removal of characters from the beginning of the
               string buffer.  SvPOK(sv) must be true and the "ptr" must be a
               pointer to somewhere inside the string buffer.  The "ptr"
               becomes the first character of the adjusted string. Uses the
               "OOK hack".  Beware: after this function returns, "ptr" and
               SvPVX(sv) may no longer refer to the same chunk of data.

                       void    sv_chop(SV* sv, char* ptr)

       sv_clear
               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 inadver-
               tently 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 wrap-
               per "SvREFCNT_dec") instead.

                       void    sv_clear(SV* sv)

       sv_cmp  Compares the strings in two SVs.  Returns -1, 0, or 1 indicat-
               ing 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 necessary.  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 variable, but transformed to
               such a format that a normal 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 performs 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.

                       void    sv_copypv(SV* dsv, SV* ssv)

       sv_dec  Auto-decrement of the value in the SV, doing string to numeric
               conversion if necessary. Handles ’get’ magic.

                       void    sv_dec(SV* sv)

       sv_derived_from
               Returns a boolean indicating whether the SV is derived from the
               specified class.  This is the function that implements "UNIVER-
               SAL::isa".  It works for class names as well as for objects.

                       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_nor-
               mal_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_normal"
               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 necessary, 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.

                       void    sv_inc(SV* sv)

       sv_insert
               Inserts a string at the specified offset/length within the SV.
               Similar to the Perl substr() function.

                       void    sv_insert(SV* bigsv, STRLEN offset, STRLEN len, char* little, STRLEN littlelen)

       sv_isa  Returns a boolean indicating whether the SV is blessed into the
               specified class.  This does not check for subtypes; use
               "sv_derived_from" to verify an inheritance relationship.

                       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. Handles 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, count-
               ing wide UTF-8 bytes as a single character. 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.

               See "sv_magicext" (which "sv_magic" now calls) for a descrip-
               tion of the handling of the "name" and "namlen" arguments.

                       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 a 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
               add more than one instance of the same ’how’.

               If "namlen" is greater than zero then a "savepvn" copy of
               "name" is stored, if "namlen" is zero then "name" is stored as-
               is and - as another special case - if "(name && namlen ==
               HEf_SVKEY)" then "name" is assumed to contain an "SV*" and is
               stored as-is with its REFCNT incremented.

               (This is now used as a subroutine by "sv_magic".)

                       MAGIC * sv_magicext(SV* sv, SV* obj, int how, MGVTBL *vtbl, const char* name, I32 namlen        )

       sv_mortalcopy
               Creates a new SV which is a copy of the original SV (using
               "sv_setsv").  The new SV is marked as mortal. 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_newmortal" and "sv_2mortal".

                       SV*     sv_mortalcopy(SV* oldsv)

       sv_newmortal
               Creates a new null SV which is mortal.  The reference 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 "SvREFCNT_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 num-
               ber 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 equiva-
               lent 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_pvbyten
               A private implementation of the "SvPVbyte" macro for compilers
               which can’t cope with complex macro expressions. Always use the
               macro instead.

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

       sv_pvbyten_force
               A private implementation of the "SvPVbytex_force" macro for
               compilers which can’t cope with complex macro expressions.
               Always use the macro instead.

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

       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 imple-
               mentation 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 various
               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 com-
               pilers 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 reference to.

                       char*   sv_reftype(SV* sv, int ob)

       sv_replace
               Make the first argument a copy of the second, then delete the
               original.  The target SV physically takes over ownership of the
               body of the source SV and inherits its flags; however, the tar-
               get keeps any magic it owns, and any magic in the source is
               discarded.  Note that this is a rather specialist SV copying
               operation; most of the time you’ll want to use "sv_setsv" or
               one of its many macro front-ends.

                       void    sv_replace(SV* sv, SV* nsv)

       sv_report_used
               Dump the contents of all SVs not yet freed. (Debugging aid).

                       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_backref" magic if it hasn’t
               already; and push a back-reference to this RV onto the array of
               backreferences associated with that magic.

                       SV*     sv_rvweaken(SV *sv)

       sv_setiv
               Copies an integer into the given SV, upgrading first if neces-
               sary.  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 neces-
               sary.  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-termi-
               nated.  Does not handle ’set’ magic.  See "sv_setpv_mg".

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

       sv_setpvf
               Works like "sv_catpvf" but copies the text into the SV instead
               of appending it.  Does not handle ’set’ magic.  See "sv_set-
               pvf_mg".

                       void    sv_setpvf(SV* sv, const char* pat, ...)

       sv_setpvf_mg
               Like "sv_setpvf", but also handles ’set’ magic.

                       void    sv_setpvf_mg(SV *sv, const char* pat, ...)

       sv_setpviv
               Copies an integer into the given SV, also updating its string
               value.  Does not handle ’set’ magic.  See "sv_setpviv_mg".

                       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.  If the "ptr" argument is NULL
               the SV will become undefined.  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 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 refer-
               ence 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 modi-
               fied to point to the new SV.  The "classname" argument indi-
               cates the package for the blessing.  Set "classname" to
               "Nullch" to avoid the blessing.  The new SV will have a refer-
               ence 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 blessing the SV.
               The "rv" argument will be upgraded to an RV.  That RV will be
               modified to point to the new SV.  If the "pv" argument is NULL
               then "PL_sv_undef" will be placed into the SV.  The "classname"
               argument indicates the package for the blessing.  Set "class-
               name" to "Nullch" to avoid the blessing.  The new SV will have
               a reference count of 1, and the RV will be returned.

               Do not use with other Perl types such as HV, AV, SV, CV,
               because those objects will become corrupted by the pointer copy
               process.

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

                       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 specified 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, 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" argu-
               ment indicates the package for the blessing.  Set "classname"
               to "Nullch" to avoid the blessing.  The new SV will have a ref-
               erence 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 function 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 desti-
               nation.

               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 function 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 desti-
               nation.  If the "flags" parameter has the "SV_GMAGIC" bit set,
               will "mg_get" on "ssv" if appropriate, else not. If the "flags"
               parameter has the "NOSTEAL" bit set then the buffers of temps
               will not be stolen. <sv_setsv> and "sv_setsv_nomg" are imple-
               mented in terms of this function.

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

               This is the primary function for copying scalars, and most
               other copy-ish functions and macros use this underneath.

                       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_setsv_nomg
               Like "sv_setsv" but doesn’t process magic.

                       void    sv_setsv_nomg(SV* dsv, SV* ssv)

       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 reversal of "newSVrv".  The "cflags"
               argument can contain "SV_IMMEDIATE_UNREF" to force the refer-
               ence count to be decremented (otherwise the decrementing is
               conditional on the reference count being different from one or
               the reference being a readonly SV).  See "SvROK_off".

                       void    sv_unref_flags(SV* sv, U32 flags)

       sv_untaint
               Untaint an SV. Use "SvTAINTED_off" instead.
                    void sv_untaint(SV* sv)

       sv_upgrade
               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 allocated by "malloc".  The string length, "len", must
               be supplied.  This function will realloc the memory pointed to
               by "ptr", so that pointer should not be freed or used by the
               programmer after giving 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
               If the PV of the SV is an octet sequence in UTF-8 and contains
               a multiple-byte character, the "SvUTF8" flag is turned on so
               that it looks like a character. If the PV contains only single-
               byte characters, the "SvUTF8" flag stays being off.  Scans PV
               for validity and returns false if the PV is invalid UTF-8.

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

                       bool    sv_utf8_decode(SV *sv)

       sv_utf8_downgrade
               Attempts to convert the PV of an SV from characters to bytes.
               If the PV contains a character beyond byte, this conversion
               will fail; in this 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.

                       bool    sv_utf8_downgrade(SV *sv, bool fail_ok)

       sv_utf8_encode
               Converts the PV of an SV to UTF-8, but then turns the "SvUTF8"
               flag off so that it looks like octets again.

                       void    sv_utf8_encode(SV *sv)

       sv_utf8_upgrade
               Converts 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 validity 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
               Converts 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 validity 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 func-
               tion.

               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_vcatpvf
               Processes its arguments like "vsprintf" and appends the format-
               ted output to an SV.  Does not handle ’set’ magic.  See
               "sv_vcatpvf_mg".

               Usually used via its frontend "sv_catpvf".

                       void    sv_vcatpvf(SV* sv, const char* pat, va_list* args)

       sv_vcatpvfn
               Processes its arguments like "vsprintf" and appends the format-
               ted output to an SV.  Uses an array of SVs if the C style vari-
               able 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_vcatpvf" and
               "sv_vcatpvf_mg".

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

       sv_vcatpvf_mg
               Like "sv_vcatpvf", but also handles ’set’ magic.

               Usually used via its frontend "sv_catpvf_mg".

                       void    sv_vcatpvf_mg(SV* sv, const char* pat, va_list* args)

       sv_vsetpvf
               Works like "sv_vcatpvf" but copies the text into the SV instead
               of appending it.  Does not handle ’set’ magic.  See "sv_vset-
               pvf_mg".

               Usually used via its frontend "sv_setpvf".

                       void    sv_vsetpvf(SV* sv, const char* pat, va_list* args)

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

               Usually used via one of its frontends "sv_vsetpvf" and
               "sv_vsetpvf_mg".

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

       sv_vsetpvf_mg
               Like "sv_vsetpvf", but also handles ’set’ magic.

               Usually used via its frontend "sv_setpvf_mg".

                       void    sv_vsetpvf_mg(SV* sv, const char* pat, va_list* args)


Unicode Support

       bytes_from_utf8
               Converts a string "s" of length "len" from UTF-8 into byte
               encoding.  Unlike <utf8_to_bytes> but like "bytes_to_utf8",
               returns a pointer to the newly-created string, and updates
               "len" to contain the new length.  Returns the original string
               if no conversion occurs, "len" is unchanged. Do nothing if
               "is_utf8" points to 0. Sets "is_utf8" to 0 if "s" is converted
               or contains all 7bit characters.

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

                       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 encodings 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 Unicode.
               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 con-
               tinue under any circumstances.  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 defin-
               ing 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/unicode/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 will be returned if it is valid, otherwise 0.

                       STRLEN  is_utf8_char(U8 *p)

       is_utf8_string
               Returns true if first "len" bytes of the given string form a
               valid UTF-8 string, false otherwise.  Note that ’a valid UTF-8
               string’ does not mean ’a string that contains code points above
               0x7F encoded in UTF-8’ because a valid ASCII string is a valid
               UTF-8 string.

                       bool    is_utf8_string(U8 *s, STRLEN len)

       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 version 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 themselves, UNI_DISPLAY_BACKSLASH
               to display the \\[nrfta\\] as the backslashed versions (like
               ’\n’) (UNI_DISPLAY_BACKSLASH is preferred over UNI_DIS-
               PLAY_ISPRINT for \\).  UNI_DISPLAY_QQ (and its alias UNI_DIS-
               PLAY_REGEX) have both UNI_DISPLAY_BACKSLASH and UNI_DIS-
               PLAY_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 decod-
               ing 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 happen.  (See lib/encoding.pm and Encode).

               The PV of the sv is returned.

                       char*   sv_recode_to_utf8(SV* sv, SV *encoding)

       sv_uni_display
               Build to the scalar dsv a displayable version of the scalar sv,
               the displayable version being at most pvlim bytes long (if
               longer, the rest is truncated and "..." will be appended).

               The flags argument is as in pv_uni_display().

               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/uni-
               core/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 ver-
               sion 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 characters).

               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 ver-
               sion 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 characters).

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

                       UV      to_utf8_lower(U8 *p, U8* ustrp, STRLEN *lenp)

       to_utf8_title
               Convert the UTF-8 encoded character at p to its titlecase ver-
               sion 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 titlecase version may be
               longer than the original character (up to two characters).

               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 ver-
               sion 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 characters).

               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 charac-
               ter.

               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 charac-
               ter.

               If "s" does not point to a well-formed UTF-8 character, 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 malformations will be given,
               "retlen" will be set to the expected length of the UTF-8 char-
               acter in bytes, and zero will be returned.

               The "flags" can also contain various flags to allow deviations
               from the strict UTF-8 encoding (see utf8.h).

               Most code should use utf8_to_uvchr() rather than call this
               directly.

                       UV      utf8n_to_uvuni(U8 *s, STRLEN curlen, STRLEN* retlen, U32 flags)

       utf8_distance
               Returns the number of UTF-8 characters between the UTF-8 point-
               ers "a" and "b".

               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 char-
               acters.  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 origi-
               nal string, and updates len to contain the new length.  Returns
               zero on failure, 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 charac-
               ter.

               If "s" does not point to a well-formed UTF-8 character, zero is
               returned and retlen is set, if possible, to -1.

                       UV      utf8_to_uvchr(U8 *s, STRLEN* retlen)

       utf8_to_uvuni
               Returns the Unicode code point 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.

               This function should only be used when returned UV is consid-
               ered an index into the Unicode semantic tables (e.g. swashes).

               If "s" does not point to a well-formed UTF-8 character, zero is
               returned and retlen is set, if possible, to -1.

                       UV      utf8_to_uvuni(U8 *s, STRLEN* retlen)

       uvchr_to_utf8
               Adds the UTF-8 representation of the Native codepoint "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 codepoint "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", "XSprePUSH" 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".

                       char*   CLASS

       dAX     Sets up the "ax" variable.  This is usually handled automati-
               cally by "xsubpp" by calling "dXSARGS".

                               dAX;

       dITEMS  Sets up the "items" variable.  This is usually handled automat-
               ically by "xsubpp" by calling "dXSARGS".

                               dITEMS;

       dXSARGS Sets up stack and mark pointers for an XSUB, calling 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 "Variable-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 pro-
               totypes 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 Variable" 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".

       XS_VERSION
               The version identifier for an XS module.  This is usually han-
               dled automatically by "ExtUtils::MakeMaker".  See "XS_VER-
               SION_BOOTCHECK".

       XS_VERSION_BOOTCHECK
               Macro to verify that a PM module’s $VERSION variable matches
               the XS module’s "XS_VERSION" variable.  This is usually handled
               automatically by "xsubpp".  See "The VERSIONCHECK: Keyword" in
               perlxs.

                               XS_VERSION_BOOTCHECK;


Warning and Dieing

       croak   This is the XSUB-writer’s interface to Perl’s "die" function.
               Normally call this function the same way you call the C
               "printf" function.  Calling "croak" returns control directly to
               Perl, sidestepping the normal C order of execution. 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.
               Call this function the same way you call the C "printf" func-
               tion.  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, Malcolm Beattie,
       Andreas Koenig, Paul Hudson, Ilya Zakharevich, Paul Marquess, Neil Bow-
       ers, 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 v5.8.6                       2004-11-05                        PERLAPI(1)

Man(1) output converted with man2html