perlapi

• NAME
• DESCRIPTION
• "Gimme" Values
• Array Manipulation Functions
• Callback Functions
• Character classes
• Cloning an interpreter
• CV Manipulation Functions
• Embedding Functions
• Functions in file pp_pack.c
• Global Variables
• GV Functions
• Handy Values
• Hash Manipulation Functions
• Magical Functions
• Memory Management
• Miscellaneous Functions
• Numeric functions
• Optree Manipulation Functions
• Pad Data Structures
• Stack Manipulation Macros
• SV Flags
• SV Manipulation Functions
• Unicode Support
• Variables created by xsubpp and xsubpp internal functions
• Warning and Dieing
• AUTHORS
• SEE ALSO

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 context, respectively.

  	U32	GIMME_V

• G_ARRAY

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

• G_DISCARD

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

• G_EVAL

  Used to force a Perl eval wrapper around a 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 initialized.

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

  	bool	av_exists(AV* ar, I32 key)

• av_extend

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

  	void	av_extend(AV* ar, I32 key)

• av_fetch

  Returns the SV at the specified index in the array. The key is the index. If lval is set then the fetch will be part of a store. Check that the return value is non-null before dereferencing 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 algorithm.

  	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 lowercase character.

  	bool	isLOWER(char ch)

• isSPACE

  Returns a boolean indicating whether the C char is whitespace.

  	bool	isSPACE(char ch)

• isUPPER

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

  	bool	isUPPER(char ch)

• toLOWER

  Converts the specified character to lowercase.

  	char	toLOWER(char ch)

• toUPPER

  Converts the specified character to uppercase.

  	char	toUPPER(char ch)

Cloning an interpreter

• perl_clone

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

  perl_clone takes these flags as parameters:

  CLONEf_COPY_STACKS - is used to, well, copy the stacks also, without it we only clone the data and zero the stacks, with it we copy the stacks and the new perl interpreter is ready to run at the exact same point as the previous one. The pseudo-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_table_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 specified, provides version semantics similar to use Foo::Bar VERSION . 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 perlembed.

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

• perl_run

  Tells a Perl interpreter to run. See perlembed.

  	int	perl_run(PerlInterpreter* interp)

• require_pv

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

  NOTE: the perl_ form of this function is 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 number 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: parameters 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-interpreter basis. In a pinch, it can also be used as a symbol table for extensions to share data among each other. It is a good idea to use keys prefixed by the package name of the extension that owns the data.

  	HV*	PL_modglobal

• PL_na

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

  	STRLEN	PL_na

• PL_sv_no

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

  	SV	PL_sv_no

• PL_sv_undef

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

  	SV	PL_sv_undef

• PL_sv_yes

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

  	SV	PL_sv_yes

GV Functions

• GvSV

  Return the SV from the GV.

  	SV*	GvSV(GV* gv)

• gv_fetchmeth

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

  The argument level should be either 0 or -1. If 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 equivalent to calling gv_fetchmethod_autoload with a non-zero autoload parameter.

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

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

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

• gv_fetchmeth_autoload

  Same as gv_fetchmeth(), but looks for autoloaded subroutines too. Returns a glob for the 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 and must be null-terminated. If create is set then the package will be created if it does not already exist. If create is not set and the package does not exist then NULL is returned.

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

• gv_stashpvn

  Returns a pointer to the stash for a specified package. name should be a valid UTF-8 string. The namelen parameter indicates the length of the name , in bytes. If create is set then the package will be created if it does not already exist. If create is not set and the package does not exist then NULL is returned.

  	HV*	gv_stashpvn(const char* name, U32 namelen, 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 temporary mortal SV* if the hash entry contains only a char* key.

  	SV*	HeSVKEY_force(HE* he)

• HeSVKEY_set

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

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

• HeVAL

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

  	SV*	HeVAL(HE* he)

• HvNAME

  Returns the package name of a stash. See 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 without tie magic.

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

  	I32	hv_iterinit(HV* tb)

• hv_iterkey

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

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

• hv_iterkeysv

  Returns the key as an SV* from the current 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. Currently a placeholder is implemented with a value that is &Perl_sv_placeholder . Note that the implementation of placeholders and restricted hashes may change, and the implementation currently is insufficiently abstracted for any change to be tidy.

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

  	HE*	hv_iternext_flags(HV* tb, I32 flags)

• hv_iterval

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

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

• hv_magic

  Adds magic to a hash. See sv_magic .

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

• hv_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 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. Effectively a successful hv_store 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. 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 afterwards.

  	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 module 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 overlapping 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)

• Newx

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

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

• Newxc

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

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

• Newxz

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

  In 5.9.3, we removed the 1st parameter, a debug aid, from the api. It was used to uniquely identify each usage of these allocation functions, but was deemed unnecessary with the availability of better memory tracking tools, valgrind for example.

  	void	Newxz(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 duplicate 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)

• savesvpv

  A version of savepv() /savepvn() which gets the string to duplicate from the passed in SV using SvPV()

  	char*	savesvpv(SV* sv)

• 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 module present. Exists to avoid test for a NULL function pointer and because it could potentially warn under some level of strict-ness.

  	void	sv_nolocking(SV *)

• sv_nosharing

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

  	void	sv_nosharing(SV *)

• sv_nounlocking

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

  	void	sv_nounlocking(SV *)

Numeric functions

• grok_bin

  converts a string representing a binary number to numeric form.

  On entry start and *len give the string to scan, *flags gives conversion flags, and result should be NULL or a pointer to an NV. The scan stops at the end of the string, or the first invalid 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 combination of IS_NUMBER_IN_UV, IS_NUMBER_GREATER_THAN_UV_MAX, IS_NUMBER_NOT_INT, IS_NUMBER_NEG, IS_NUMBER_INFINITY, IS_NUMBER_NAN (defined in perl.h).

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

  IS_NUMBER_NOT_INT will be set with IS_NUMBER_IN_UV if trailing decimals were seen (in which case *valuep gives the true value truncated to an 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_p, 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 necessary. 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 use POPpx.

  	char*	POPp

• POPpbytex

  Pops a string off the stack which must consist of bytes i.e. characters < 256.

  	char*	POPpbytex

• POPpx

  Pops a string off the stack.

  	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 multiple 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 multiple 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 perlcall.

  		SPAGAIN;

• XPUSHi

  Push an 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 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 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.

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

• looks_like_number

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

  	I32	looks_like_number(SV* sv)

• newRV_inc

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

  	SV*	newRV_inc(SV* sv)

• newRV_noinc

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

  	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)

• newSVhek

  Creates a new SV from the hash key structure. It will generate scalars that point to the shared string table where possible. Returns a new (undefined) SV if the hek is NULL.

  	SV*	newSVhek(const HEK *hek)

• 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 compute the length using strlen(). For efficiency, consider using newSVpvn instead.

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

• newSVpvf

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

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

• newSVpvn

  Creates a new SV and copies a string into it. The reference count for the SV is set to 1. Note that if len is zero, Perl will create a zero length string. You are responsible for ensuring that the source string is at least len bytes long. 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_const 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_const == 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 current length of the string which is in the SV. See SvCUR and SvIV_set .

  	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 integer.

  	bool	SvIOK(SV* sv)

• SvIOKp

  Returns a boolean indicating whether the SV contains an integer. 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

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

  	IV	SvIVX(SV* sv)

• SvIVx

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

  	IV	SvIVx(SV* sv)

• SvIV_set

  Set the value of the IV pointer in sv to val. It is possible to perform the same function of this macro with an lvalue assignment to SvIVX . With future Perls, however, it will be more efficient to use SvIV_set instead of the lvalue assignment to SvIVX .

  	void	SvIV_set(SV* sv, IV val)

• SvLEN

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

  	STRLEN	SvLEN(SV* sv)

• SvLEN_set

  Set the actual length of the string which is in the SV. See SvIV_set .

  	void	SvLEN_set(SV* sv, STRLEN len)

• SvMAGIC_set

  Set the value of the MAGIC pointer in sv to val. See SvIV_set .

  	void	SvMAGIC_set(SV* sv, MAGIC* val)

• 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

  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)

• 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)

• SvNV_set

  Set the value of the NV pointer in sv to val. See SvIV_set .

  	void	SvNV_set(SV* sv, NV val)

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

  	bool	SvOOK(SV* sv)

• SvPOK

  Returns a boolean indicating whether the SV contains a character string.

  	bool	SvPOK(SV* sv)

• SvPOKp

  Returns a boolean indicating whether the SV contains a character 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 evaluate 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. Guarantees to evaluate sv only once; use the more efficient SvPVutf8 otherwise.

  	char*	SvPVutf8x(SV* sv, STRLEN len)

• SvPVutf8x_force

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

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

  	char*	SvPVX(SV* sv)

• SvPVx

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

  	char*	SvPVx(SV* sv, STRLEN len)

• SvPV_force

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

  	char*	SvPV_force(SV* sv, STRLEN len)

• SvPV_force_nomg

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

  	char*	SvPV_force_nomg(SV* sv, STRLEN len)

• 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)

• SvPV_set

  Set the value of the PV pointer in sv to val. See SvIV_set .

  	void	SvPV_set(SV* sv, char* val)

• 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)

• SvRV_set

  Set the value of the RV pointer in sv to val. See SvIV_set .

  	void	SvRV_set(SV* sv, SV* val)

• SvSTASH

  Returns the stash of the SV.

  	HV*	SvSTASH(SV* sv)

• SvSTASH_set

  Set the value of the STASH pointer in sv to val. See SvIV_set .

  	void	SvSTASH_set(SV* sv, STASH* val)

• SvTAINT

  Taints an SV if tainting is enabled.

  	void	SvTAINT(SV* sv)

• SvTAINTED

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

  	bool	SvTAINTED(SV* sv)

• SvTAINTED_off

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

  	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

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

  	UV	SvUVX(SV* sv)

• SvUVx

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

  	UV	SvUVx(SV* sv)

• SvUV_set

  Set the value of the UV pointer in sv to val. See SvIV_set .

  	void	SvUV_set(SV* sv, UV val)

• 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 usually end up here too.

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

• sv_2pv_nolen

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

• sv_2uv

  Return the unsigned integer value of an SV, doing any necessary string conversion, magic etc. 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 formatted output to an SV. If the appended data contains "wide" characters (including, but not limited to, SVs with a UTF-8 PV formatted with %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 . If the original SV was UTF-8, the pattern should be valid UTF-8; if the original SV was bytes, the pattern should be too.

  	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_catpvn_nomg are implemented in terms of this function.

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

• sv_catpvn_mg

  Like sv_catpvn , but also handles 'set' magic.

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

• sv_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 appropriate, else not. sv_catsv and sv_catsv_nomg are implemented in terms of this function.

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

• sv_catsv_mg

  Like sv_catsv , but also handles 'set' magic.

  	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_const(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 inadvertently be assumed to be live during global destruction etc. This function should only be called when REFCNT is zero. Most of the time you'll want to call sv_free() (or its macro wrapper SvREFCNT_dec ) instead.

  	void	sv_clear(SV* sv)

• sv_cmp

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

  	void	sv_force_normal(SV *sv)

• sv_force_normal_flags

  Undo various types of fakery on an SV: if the PV is a shared string, make a private copy; if we're a ref, stop refing; if we're a glob, downgrade to an xpvmg. The flags parameter gets passed to sv_unref_flags() when unrefing. sv_force_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, counting 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 description of the handling of the name and namlen arguments.

  You need to use sv_magicext to add magic to SvREADONLY SVs and also to add more than one instance of the same 'how'.

  	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 number of UTF-8 chars. Handles magic and type coercion.

  	void	sv_pos_b2u(SV* sv, I32* offsetp)

• sv_pos_u2b

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

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

• sv_pv

  Use the SvPV_nolen macro instead

  	char*	sv_pv(SV *sv)

• sv_pvbyte

  Use SvPVbyte_nolen instead.

  	char*	sv_pvbyte(SV *sv)

• sv_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 implementation of the SvPV_force macro for compilers which can't cope with complex macro expressions. Always use the macro instead.

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

• sv_pvn_force_flags

  Get a sensible string out of the SV somehow. If flags has SV_GMAGIC bit set, will mg_get on sv if appropriate, else not. sv_pvn_force and sv_pvn_force_nomg are implemented in terms of this function. You normally want to use the 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 compilers which can't cope with complex macro expressions. Always use the macro instead.

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

• sv_reftype

  Returns a string describing what the SV is a 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 target 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 necessary. Does not handle 'set' magic. See also sv_setiv_mg .

  	void	sv_setiv(SV* sv, IV num)

• sv_setiv_mg

  Like sv_setiv , but also handles 'set' magic.

  	void	sv_setiv_mg(SV *sv, IV i)

• sv_setnv

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

  	void	sv_setnv(SV* sv, NV num)

• sv_setnv_mg

  Like sv_setnv , but also handles 'set' magic.

  	void	sv_setnv_mg(SV *sv, NV num)

• sv_setpv

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

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

• sv_setpvf

  Works like sv_catpvf but copies the text into the SV instead of appending it. Does not handle 'set' magic. See sv_setpvf_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 reference count of 1, and the RV will be returned.

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

• sv_setref_nv

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

  	SV*	sv_setref_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 classname 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 argument indicates the package for the blessing. Set classname to Nullch to avoid the blessing. The new SV will have a reference count of 1, and the RV will be returned.

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

• sv_setsv

  Copies the contents of the source SV ssv into the destination SV dsv . The source SV may be destroyed if it is mortal, so don't use this 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 destination.

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

  	void	sv_setsv(SV* dsv, SV* ssv)

• sv_setsv_flags

  Copies the contents of the source SV ssv into the destination SV dsv . The source SV may be destroyed if it is mortal, so don't use this 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 destination. 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 implemented 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 reference 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 function.

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

  	STRLEN	sv_utf8_upgrade_flags(SV *sv, I32 flags)

• sv_uv

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

  	UV	sv_uv(SV* sv)

• sv_vcatpvf

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

  XXX Except that it maybe_tainted is never assigned to.

  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_vsetpvf_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 continue 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 defining a successful match: all the scans that define an explicit length must reach their goal pointers for a match to succeed).

  For case-insensitiveness, the "casefolding" of Unicode is used instead of upper/lowercasing both the characters, see http://www.unicode.org/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.

  See also is_utf8_string_loclen() and is_utf8_string_loc().

  	bool	is_utf8_string(U8 *s, STRLEN len)

• is_utf8_string_loc

  Like is_utf8_string() but stores the location of the failure (in the case of "utf8ness failure") or the location s+len (in the case of "utf8ness success") in the ep .

  See also is_utf8_string_loclen() and is_utf8_string().

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

• is_utf8_string_loclen

  Like is_utf8_string() but stores the location of the failure (in the case of "utf8ness failure") or the location s+len (in the case of "utf8ness success") in the ep , and the number of UTF-8 encoded characters in the el .

  See also is_utf8_string_loc() and is_utf8_string().

  	bool	is_utf8_string_loclen(const U8 *s, STRLEN len, const U8 **ep, STRLEN *el)

• 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_DISPLAY_ISPRINT for \\). UNI_DISPLAY_QQ (and its alias UNI_DISPLAY_REGEX) have both UNI_DISPLAY_BACKSLASH and UNI_DISPLAY_ISPRINT turned on.

  The pointer to the PV of the dsv is returned.

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

• sv_cat_decode

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

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

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

• sv_recode_to_utf8

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

  If the sv already is UTF-8 (or if it is not POK), or if the encoding is not a reference, nothing is done to the sv. If the encoding is not an Encode::XS Encoding object, bad things will 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/unicore/To/Foo.pl, and loaded by SWASHGET, using lib/utf8_heavy.pl. The special (usually, but not always, a multicharacter mapping), is tried first.

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

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

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

• to_utf8_fold

  Convert the UTF-8 encoded character at p to its foldcase version and store that in UTF-8 in ustrp and its length in bytes in lenp. Note that the ustrp needs to be at least UTF8_MAXBYTES_CASE+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 version and store that in UTF-8 in ustrp and its length in bytes in lenp. Note that the ustrp needs to be at least UTF8_MAXBYTES_CASE+1 bytes since the lowercase version may be longer than the original character.

  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 version and store that in UTF-8 in ustrp and its length in bytes in lenp. Note that the ustrp needs to be at least UTF8_MAXBYTES_CASE+1 bytes since the titlecase version may be longer than the original character.

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

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

• to_utf8_upper

  Convert the UTF-8 encoded character at p to its uppercase version and store that in UTF-8 in ustrp and its length in bytes in lenp. Note that the ustrp needs to be at least UTF8_MAXBYTES_CASE+1 bytes since the uppercase version may be longer than the original character.

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

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

• utf8n_to_uvchr

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

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

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

• utf8n_to_uvuni

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

  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 character 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 pointers 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 characters. Stops at e (inclusive). If e < s or if the scan would end up past e , croaks.

  	STRLEN	utf8_length(U8* s, U8 *e)

• utf8_to_bytes

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

  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 considered 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_MAXBYTES+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_MAXBYTES+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 automatically by xsubpp by calling dXSARGS .

  		dAX;

• dAXMARK

  Sets up the ax variable and stack marker variable mark . This is usually handled automatically by xsubpp by calling dXSARGS .

  		dAXMARK;

• dITEMS

  Sets up the items variable. This is usually handled automatically 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 prototypes to the subs.

• RETVAL

  Variable which is setup by xsubpp to hold the return value for an XSUB. This is always the proper type for the XSUB. See The RETVAL 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 handled automatically by ExtUtils::MakeMaker . See XS_VERSION_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 function. See croak .

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

AUTHORS

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

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

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

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

SEE ALSO

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