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X11R7.4 - man page for perlapi (x11r4 section 1)

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

NAME
       perlapi - autogenerated documentation for the perl public API

DESCRIPTION
       This file contains the documentation of the perl public API generated by embed.pl, specif-
       ically 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 perl-
	       call.

       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_create_and_push
	       Push an SV onto the end of the array, creating the array if necessary.  A small
	       internal helper function to remove a commonly duplicated idiom.

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

		       void    av_create_and_push(AV **const avp, SV *const val)

       av_create_and_unshift_one
	       Unshifts an SV onto the beginning of the array, creating the array if necessary.
	       A small internal helper function to remove a commonly duplicated idiom.

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

		       SV**    av_create_and_unshift_one(AV **const avp, SV *const val)

       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 Set the highest index in the array to the given number, equivalent to Perl's
	       "$#array = $fill;".

	       The number of elements in the an array will be "fill + 1" after av_fill() returns.
	       If the array was previously shorter then the additional elements appended are set
	       to "PL_sv_undef".  If the array was longer, then the excess elements are freed.
	       "av_fill(av, -1)" is the same as "av_clear(av)".

		       void    av_fill(AV* ar, I32 fill)

       av_len  Returns the highest index in the array.	The number of elements in the array is
	       "av_len(av) + 1".  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. Returns &PL_sv_undef if the array is
	       empty.

		       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 decre-
	       menting 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 vari-
	       able does not exist then it will be created.  If "create" is not set and the vari-
	       able 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, VOL 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 charac-
	       ter (including underscore) or digit.

		       bool    isALNUM(char ch)

       isALPHA Returns a boolean indicating whether the C "char" is an ASCII alphabetic charac-
	       ter.

		       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->create 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 sepa-
	       rate perl interpreter and then throw it away and return to the original one, you
	       don't need to do anything.

		       PerlInterpreter*        perl_clone(PerlInterpreter* interp, UV flags)

CV Manipulation Functions
       CvSTASH Returns the stash of the CV.

		       HV*     CvSTASH(CV* cv)

       get_cv  Uses "strlen" to get the length of "name", then calls "get_cvn_flags".

	       NOTE: the perl_ form of this function is deprecated.

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

       get_cvn_flags
	       Returns the CV of the specified Perl subroutine.  "flags" are passed to "gv_fetch-
	       pvn_flags". If "GV_ADD" is set and the Perl subroutine does not exist then it will
	       be declared (which has the same effect as saying "sub name;").  If "GV_ADD" is not
	       set and the subroutine does not exist then NULL is returned.

	       NOTE: the perl_ form of this function is deprecated.

		       CV*     get_cvn_flags(const char* name, STRLEN len, I32 flags)

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 dump.c
       pv_display
	       Similar to

		 pv_escape(dsv,pv,cur,pvlim,PERL_PV_ESCAPE_QUOTE);

	       except that an additional "\0" will be appended to the string when len > cur and
	       pv[cur] is "\0".

	       Note that the final string may be up to 7 chars longer than pvlim.

		       char*   pv_display(SV *dsv, char *pv, STRLEN cur, STRLEN len, STRLEN pvlim)

       pv_escape
	       Escapes at most the first "count" chars of pv and puts the results into dsv such
	       that the size of the escaped string will not exceed "max" chars and will not con-
	       tain any incomplete escape sequences.

	       If flags contains PERL_PV_ESCAPE_QUOTE then any double quotes in the string will
	       also be escaped.

	       Normally the SV will be cleared before the escaped string is prepared, but when
	       PERL_PV_ESCAPE_NOCLEAR is set this will not occur.

	       If PERL_PV_ESCAPE_UNI is set then the input string is treated as Unicode, if
	       PERL_PV_ESCAPE_UNI_DETECT is set then the input string is scanned using
	       "is_utf8_string()" to determine if it is Unicode.

	       If PERL_PV_ESCAPE_ALL is set then all input chars will be output using "\x01F1"
	       style escapes, otherwise only chars above 255 will be escaped using this style,
	       other non printable chars will use octal or common escaped patterns like "\n". If
	       PERL_PV_ESCAPE_NOBACKSLASH then all chars below 255 will be treated as printable
	       and will be output as literals.

	       If PERL_PV_ESCAPE_FIRSTCHAR is set then only the first char of the string will be
	       escaped, regardles of max. If the string is utf8 and the chars value is >255 then
	       it will be returned as a plain hex sequence. Thus the output will either be a sin-
	       gle char, an octal escape sequence, a special escape like "\n" or a 3 or more
	       digit hex value.

	       Returns a pointer to the escaped text as held by dsv.

		       char*   pv_escape(SV *dsv, char const * const str, const STRLEN count, const STRLEN max, STRLEN * const escaped, const U32 flags)

       pv_pretty
	       Converts a string into something presentable, handling escaping via pv_escape()
	       and supporting quoting and elipses.

	       If the PERL_PV_PRETTY_QUOTE flag is set then the result will be double quoted with
	       any double quotes in the string escaped. Otherwise if the PERL_PV_PRETTY_LTGT flag
	       is set then the result be wrapped in angle brackets.

	       If the PERL_PV_PRETTY_ELIPSES flag is set and not all characters in string were
	       output then an elipses "..." will be appended to the string. Note that this hap-
	       pens AFTER it has been quoted.

	       If start_color is non-null then it will be inserted after the opening quote (if
	       there is one) but before the escaped text. If end_color is non-null then it will
	       be inserted after the escaped text but before any quotes or elipses.

	       Returns a pointer to the prettified text as held by dsv.

		       char*   pv_pretty(SV *dsv, char const * const str, const STRLEN count, const STRLEN max, char const * const start_color, char const * const end_color, const U32 flags)

Functions in file mathoms.c
       gv_fetchmethod
	       See gv_fetchmethod_autoload.

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

       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)

       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_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_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_catpvn_mg
	       Like "sv_catpvn", but also handles 'set' magic.

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

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

		       void    sv_catsv_mg(SV *dstr, SV *sstr)

       sv_force_normal
	       Undo various types of fakery on an SV: if the PV is a shared string, make a pri-
	       vate 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_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_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.

	       "Superseded" by sv_nosharing().

		       void    sv_nolocking(SV *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.

	       "Superseded" by sv_nosharing().

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

       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_usepvn
	       Tells an SV to use "ptr" to find its string value. Implemented by calling
	       "sv_usepvn_flags" with "flags" of 0, hence does not handle 'set' magic. See
	       "sv_usepvn_flags".

		       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_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)

       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)

Functions in file pp_ctl.c
       find_runcv
	       Locate the CV corresponding to the currently executing sub or eval.  If db_seqp is
	       non_null, skip CVs that are in the DB package and populate *db_seqp with the cop
	       sequence number at the point that the DB:: code was entered. (allows debuggers to
	       eval in the scope of the breakpoint rather than in the scope of the debugger
	       itself).

		       CV*     find_runcv(U32 *db_seqp)

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)

       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)

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_const_sv
	       If "gv" is a typeglob whose subroutine entry is a constant sub eligible for inlin-
	       ing, or "gv" is a placeholder reference that would be promoted to such a typeglob,
	       then returns the value returned by the sub.  Otherwise, returns NULL.

		       SV*     gv_const_sv(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 UNIVER-
	       SAL::.

	       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_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" parame-
	       ter.

	       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.	Uses "strlen" to deter-
	       mine the length of "name", then calls "gv_stashpvn()".

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

       gv_stashpvn
	       Returns a pointer to the stash for a specified package.	The "namelen" parameter
	       indicates the length of the "name", in bytes.  "flags" is passed to "gv_fetch-
	       pvn_flags()", so if set to "GV_ADD" then the package will be created if it does
	       not already exist.  If the package does not exist and "flags" is 0 (or any other
	       setting that does not create packages) then NULL is returned.

		       HV*     gv_stashpvn(const char* name, U32 namelen, I32 flags)

       gv_stashpvs
	       Like "gv_stashpvn", but takes a literal string instead of a string/length pair.

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

       gv_stashsv
	       Returns a pointer to the stash for a specified package.	See "gv_stashpvn".

		       HV*     gv_stashsv(SV* sv, I32 flags)

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 vari-
	       able does not exist then it will be created.  If "create" is not set and the vari-
	       able 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 find-
	       ing 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. See also "HeUTF8".

	       If you are using "HePV" to get values to pass to "newSVpvn()" to create a new SV,
	       you should consider using "newSVhek(HeKEY_hek(he))" as it is more efficient.

		       char*   HePV(HE* he, STRLEN len)

       HeSVKEY Returns the key as an "SV*", or "NULL" 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 indi-
	       cate the presence of an "SV*" key, and returns the same "SV*".

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

       HeUTF8  Returns whether the "char *" value returned by "HePV" is encoded in UTF-8, doing
	       any necessary dereferencing of possibly "SV*" keys.  The value returned will be 0
	       or non-0, not necessarily 1 (or even a value with any low bits set), so do not
	       blindly assign this to a "bool" variable, as "bool" may be a typedef for "char".

		       char*   HeUTF8(HE* he, STRLEN len)

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

		       SV*     HeVAL(HE* he)

       HvNAME  Returns the package name of a stash, or NULL if "stash" isn't a stash.  See "SvS-
	       TASH", "CvSTASH".

		       char*   HvNAME(HV* stash)

       hv_assert
	       Check that a hash is in an internally consistent state.

		       void    hv_assert(HV* tb)

       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_DIS-
	       CARD 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_fetchs
	       Like "hv_fetch", but takes a literal string instead of a string/length pair.

		       SV**    hv_fetchs(HV* tb, const char* key, 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 itera-
	       tor 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 immedi-
	       ately else the entry will leak - call "hv_iternext" to trigger the resource deal-
	       location.

		       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 place-
	       holder is implemented with a value that is &Perl_sv_placeholder. Note that the
	       implementation of placeholders and restricted hashes may change, and the implemen-
	       tation 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 refer-
	       ence 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 any-
	       thing 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_stores
	       Like "hv_store", but takes a literal string instead of a string/length pair and
	       omits the hash parameter.

		       SV**    hv_stores(HV* tb, const char* key, NULLOK SV* val)

       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 responsi-
	       ble 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 argu-
	       ment 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 argu-
	       ment 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 opti-
	       mise.

		       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 opti-
	       mise.

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

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

	       In 5.9.3, Newx() and friends replace the older New() API, and drops the first
	       parameter, x, a debug aid which allowed callers to identify themselves.	This aid
	       has been superseded by a new build option, PERL_MEM_LOG (see "PERL_MEM_LOG" in
	       perlhack).  The older API is still there for use in XS modules supporting older
	       perls.

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

       Newxc   The XSUB-writer's interface to the C "malloc" function, with cast.  See also
	       "Newx".

		       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".  See also "Newx".

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

       Poison  PoisonWith(0xEF) for catching access to freed memory.

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

       PoisonFree
	       PoisonWith(0xEF) for catching access to freed memory.

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

       PoisonNew
	       PoisonWith(0xAB) for catching access to allocated but uninitialized memory.

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

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

		       void    PoisonWith(void* dest, int nitems, type, U8 byte)

       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",
	       plus a trailing NUL byte. The memory allocated for the new string can be freed
	       with the "Safefree()" function.

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

       savepvs Like "savepvn", but takes a literal string instead of a string/length pair.

		       char*   savepvs(const char* s)

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

		       char*   savesharedpv(const char* pv)

       savesharedpvn
	       A version of "savepvn()" which allocates the duplicate string in memory which is
	       shared between threads. (With the specific difference that a NULL pointer is not
	       acceptable)

		       char*   savesharedpvn(const char *const pv, const STRLEN len)

       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 desti-
	       nation, "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 opti-
	       mise.

		       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 "NULL" 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)

       my_snprintf
	       The C library "snprintf" functionality, if available and standards-compliant (uses
	       "vsnprintf", actually).	However, if the "vsnprintf" is not available, will unfor-
	       tunately use the unsafe "vsprintf" which can overrun the buffer (there is an over-
	       run check, but that may be too late).  Consider using "sv_vcatpvf" instead, or
	       getting "vsnprintf".

		       int     my_snprintf(char *buffer, const Size_t len, const char *format, ...)

       my_sprintf
	       The C library "sprintf", wrapped if necessary, to ensure that it will return the
	       length of the string written to the buffer. Only rare pre-ANSI systems need the
	       wrapper function - usually this is a direct call to "sprintf".

		       int     my_sprintf(char *buffer, const char *pat, ...)

       my_vsnprintf
	       The C library "vsnprintf" if available and standards-compliant.	However, if if
	       the "vsnprintf" is not available, will unfortunately use the unsafe "vsprintf"
	       which can overrun the buffer (there is an overrun check, but that may be too
	       late).  Consider using "sv_vcatpvf" instead, or getting "vsnprintf".

		       int     my_vsnprintf(char *buffer, const Size_t len, const char *format, va_list ap)

       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 sec-
	       ond, "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 num-
	       ber 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_destroyable
	       Dummy routine which reports that object can be destroyed when there is no sharing
	       module present.	It ignores its single SV argument, and returns 'true'.	Exists to
	       avoid test for a NULL function pointer and because it could potentially warn under
	       some level of strict-ness.

		       bool    sv_destroyable(SV *sv)

       sv_nosharing
	       Dummy routine which "shares" an SV when there is no sharing module present.  Or
	       "locks" it. Or "unlocks" it. In other words, ignores its single SV argument.
	       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)

Multicall Functions
       dMULTICALL
	       Declare local variables for a multicall. See "Lightweight Callbacks" in perlcall.

			       dMULTICALL;

       MULTICALL
	       Make a lightweight callback. See "Lightweight Callbacks" in perlcall.

			       MULTICALL;

       POP_MULTICALL
	       Closing bracket for a lightweight callback.  See "Lightweight Callbacks" in perl-
	       call.

			       POP_MULTICALL;

       PUSH_MULTICALL
	       Opening bracket for a lightweight callback.  See "Lightweight Callbacks" in perl-
	       call.

			       PUSH_MULTICALL;

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_UNDER-
	       SCORES" 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_DIS-
	       ALLOW_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 unrecog-
	       nised), otherwise it is a bit-ORed combination of IS_NUMBER_IN_UV, IS_NUM-
	       BER_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_NUM-
	       BER_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_NUM-
	       BER_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)

       Perl_signbit
	       Return a non-zero integer if the sign bit on an NV is set, and 0 if it is not.

	       If Configure detects this system has a signbit() that will work with our NVs, then
	       we just use it via the #define in perl.h.  Otherwise, fall back on this implemen-
	       tation.	As a first pass, this gets everything right except -0.0.  Alas, catching
	       -0.0 is the main use for this function, so this is not too helpful yet.	Still, at
	       least we have the scaffolding in place to support other systems, should that prove
	       useful.

	       Configure notes:  This function is called 'Perl_signbit' instead of a plain 'sign-
	       bit' because it is easy to imagine a system having a signbit() function or macro
	       that doesn't happen to work with our particular choice of NVs.  We shouldn't just
	       re-#define signbit as Perl_signbit and expect the standard system headers to be
	       happy.  Also, this is a no-context function (no pTHX_) because Perl_signbit() is
	       usually re-#defined in perl.h as a simple macro call to the system's signbit().
	       Users should just always call Perl_signbit().

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

		       int     Perl_signbit(NV f)

       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 Func-
	       tions" 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.	filename needs to be static stor-
	       age, as it is used directly as CvFILE(), without a copy being made.

Pad Data Structures
       pad_sv  Get the value at offset po in the current pad.  Use macro PAD_SV instead of call-
	       ing this function directly.

		       SV*     pad_sv(PADOFFSET po)

Simple Exception Handling Macros
       dXCPT   Set up necessary local variables for exception handling.  See "Exception Handling"
	       in perlguts.

			       dXCPT;

       XCPT_CATCH
	       Introduces a catch block.  See "Exception Handling" in perlguts.

       XCPT_RETHROW
	       Rethrows a previously caught exception.	See "Exception Handling" in perlguts.

			       XCPT_RETHROW;

       XCPT_TRY_END
	       Ends a try block.  See "Exception Handling" in perlguts.

       XCPT_TRY_START
	       Starts a try block.  See "Exception Handling" in perlguts.

Stack Manipulation Macros
       dMARK   Declare a stack marker variable, "mark", for the XSUB.  See "MARK" and "dORIG-
	       MARK".

			       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, guaran-
	       tees 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.  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.  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.  Does not use "TARG".	See also "PUSHp",
	       "mXPUSHp" and "XPUSHp".

		       void    mPUSHp(char* str, STRLEN len)

       mPUSHs  Push an SV onto the stack and mortalizes the SV.  The stack must have room for
	       this element.  Does not use "TARG".  See also "PUSHs" and "mXPUSHs".

		       void    mPUSHs(SV* sv)

       mPUSHu  Push an unsigned integer onto the stack.  The stack must have room for this ele-
	       ment.  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.  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.	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" indi-
	       cates the length of the string.	Does not use "TARG".  See also "XPUSHp", "mPUSHp"
	       and "PUSHp".

		       void    mXPUSHp(char* str, STRLEN len)

       mXPUSHs Push an SV onto the stack, extending the stack if necessary and mortalizes the SV.
	       Does not use "TARG".  See also "XPUSHs" and "mPUSHs".

		       void    mXPUSHs(SV* sv)

       mXPUSHu Push an unsigned integer onto the stack, extending the stack if necessary.  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.  Han-
	       dles '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 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 ele-
	       ment.  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
	       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" indi-
	       cates 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 "PUSHmor-
	       tal".

		       void    XPUSHs(SV* sv)

       XPUSHu  Push an unsigned integer onto the stack, extending the stack if necessary.  Han-
	       dles '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 han-
	       dled 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)

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

		       SV*     newRV_inc(SV* sv)

       newSVpvn_utf8
	       Creates a new SV and copies a string into it.  If utf8 is true, calls "SvUTF8_on"
	       on the new SV.  Implemented as a wrapper around "newSVpvn_flags".

		       SV*     newSVpvn_utf8(NULLOK const char* s, STRLEN len, U32 utf8)

       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 num-
	       ber 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 U32 value indicating whether the SV contains an integer.

		       U32     SvIOK(SV* sv)

       SvIOKp  Returns a U32 value indicating whether the SV contains an integer.  Checks the
	       private setting.  Use "SvIOK".

		       U32     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. Only use this if "sv" is an expression with side effects, otherwise use
	       the more efficient "SvIV".

		       IV      SvIVx(SV* sv)

       SvIV_nomg
	       Like "SvIV" but doesn't process magic.

		       IV      SvIV_nomg(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 assign-
	       ment to "SvIVX".

		       void    SvIV_set(SV* sv, IV val)

       SvLEN   Returns the size of the string buffer in the SV, not including any part attribut-
	       able 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 U32 value indicating whether the SV contains a number, integer or dou-
	       ble.

		       U32     SvNIOK(SV* sv)

       SvNIOKp Returns a U32 value indicating whether the SV contains a number, integer or dou-
	       ble.  Checks the private setting.  Use "SvNIOK".

		       U32     SvNIOKp(SV* sv)

       SvNIOK_off
	       Unsets the NV/IV status of an SV.

		       void    SvNIOK_off(SV* sv)

       SvNOK   Returns a U32 value indicating whether the SV contains a double.

		       U32     SvNOK(SV* sv)

       SvNOKp  Returns a U32 value indicating whether the SV contains a double.  Checks the pri-
	       vate setting.  Use "SvNOK".

		       U32     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. Only use this if "sv" is an expression with side effects, otherwise use the
	       more efficient "SvNV".

		       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 U32 value indicating whether the value is an SV. It also tells whether
	       the value is defined or not.

		       U32     SvOK(SV* sv)

       SvOOK   Returns a U32 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).

		       U32     SvOOK(SV* sv)

       SvPOK   Returns a U32 value indicating whether the SV contains a character string.

		       U32     SvPOK(SV* sv)

       SvPOKp  Returns a U32 value indicating whether the SV contains a character string.  Checks
	       the private setting.  Use "SvPOK".

		       U32     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.	Guaran-
	       tees 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" oth-
	       erwise.

		       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.  Only use this if
	       "sv" is an expression with side effects, otherwise use the more efficient "SvPVX".

		       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_nomg
	       Like "SvPV" but doesn't process magic.

		       char*   SvPV_nomg(SV* sv, STRLEN len)

       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.

	       All of the following SvREFCNT_inc* macros are optimized versions of SvREFCNT_inc,
	       and can be replaced with SvREFCNT_inc.

		       SV*     SvREFCNT_inc(SV* sv)

       SvREFCNT_inc_NN
	       Same as SvREFCNT_inc, but can only be used if you know sv is not NULL.  Since we
	       don't have to check the NULLness, it's faster and smaller.

		       SV*     SvREFCNT_inc_NN(SV* sv)

       SvREFCNT_inc_simple
	       Same as SvREFCNT_inc, but can only be used with expressions without side effects.
	       Since we don't have to store a temporary value, it's faster.

		       SV*     SvREFCNT_inc_simple(SV* sv)

       SvREFCNT_inc_simple_NN
	       Same as SvREFCNT_inc_simple, but can only be used if you know sv is not NULL.
	       Since we don't have to check the NULLness, it's faster and smaller.

		       SV*     SvREFCNT_inc_simple_NN(SV* sv)

       SvREFCNT_inc_simple_void
	       Same as SvREFCNT_inc_simple, but can only be used if you don't need the return
	       value.  The macro doesn't need to return a meaningful value.

		       void    SvREFCNT_inc_simple_void(SV* sv)

       SvREFCNT_inc_simple_void_NN
	       Same as SvREFCNT_inc, but can only be used if you don't need the return value, and
	       you know that sv is not NULL.  The macro doesn't need to return a meaningful
	       value, or check for NULLness, so it's smaller and faster.

		       void    SvREFCNT_inc_simple_void_NN(SV* sv)

       SvREFCNT_inc_void
	       Same as SvREFCNT_inc, but can only be used if you don't need the return value.
	       The macro doesn't need to return a meaningful value.

		       void    SvREFCNT_inc_void(SV* sv)

       SvREFCNT_inc_void_NN
	       Same as SvREFCNT_inc, but can only be used if you don't need the return value, and
	       you know that sv is not NULL.  The macro doesn't need to return a meaningful
	       value, or check for NULLness, so it's smaller and faster.

		       void    SvREFCNT_inc_void_NN(SV* sv)

       SvROK   Tests if the SV is an RV.

		       U32     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, HV* 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 func-
	       tion unless they fully understand all the implications of unconditionally untaint-
	       ing the value. Untainting should be done in the standard perl fashion, via a care-
	       fully 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.

		       bool    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 U32 value indicating whether the SV contains UTF-8 encoded data.  Call
	       this after SvPV() in case any call to string overloading updates the internal
	       flag.

		       U32     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 "sv"
	       only once. Only use this if "sv" is an expression with side effects, otherwise use
	       the more efficient "SvUV".

		       UV      SvUVx(SV* sv)

       SvUV_nomg
	       Like "SvUV" but doesn't process magic.

		       UV      SvUV_nomg(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_catpvn_nomg
	       Like "sv_catpvn" but doesn't process magic.

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

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

		       void    sv_catsv_nomg(SV* dsv, SV* ssv)

       sv_derived_from
	       Returns a boolean indicating whether the SV is derived from the specified class at
	       the C level.  To check derivation at the Perl level, call "isa()" as a normal Perl
	       method.

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

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

		       void    sv_report_used()

       sv_setsv_nomg
	       Like "sv_setsv" but doesn't process magic.

		       void    sv_setsv_nomg(SV* dsv, SV* ssv)

SV-Body Allocation
       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_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 trailing 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.

	       In 5.9.3, newSV() replaces the older NEWSV() API, and drops the first parameter,
	       x, a debug aid which allowed callers to identify themselves.  This aid has been
	       superseded by a new build option, PERL_MEM_LOG (see "PERL_MEM_LOG" in perlhack).
	       The older API is still there for use in XS modules supporting older perls.

		       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_flags
	       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.  Currently the only flag
	       bits accepted are "SVf_UTF8" and "SVs_TEMP".  If "SVs_TEMP" is set, then "sv2mor-
	       tal()" is called on the result before returning. If "SVf_UTF8" is set, then it
	       will be set on the new SV.  "newSVpvn_utf8()" is a convenience wrapper for this
	       function, defined as

		   #define newSVpvn_utf8(s, len, u)		       \
		       newSVpvn_flags((s), (len), (u) ? SVf_UTF8 : 0)

		       SV*     newSVpvn_flags(const char* s, STRLEN len, U32 flags)

       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. If the "hash" parameter is non-zero, that value is
	       used; otherwise the hash is computed. The string's hash can be later be retrieved
	       from the SV with the "SvSHARED_HASH()" macro. 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)

       newSVpvs
	       Like "newSVpvn", but takes a literal string instead of a string/length pair.

		       SV*     newSVpvs(const char* s)

       newSVpvs_flags
	       Like "newSVpvn_flags", but takes a literal string instead of a string/length pair.

		       SV*     newSVpvs_flags(const char* s, U32 flags)

       newSVpvs_share
	       Like "newSVpvn_share", but takes a literal string instead of a string/length pair
	       and omits the hash parameter.

		       SV*     newSVpvs_share(const char* s)

       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)

       newSV_type
	       Creates a new SV, of the type specified.  The reference count for the new SV is
	       set to 1.

		       SV*     newSV_type(svtype type)

       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.  The flags in "lref" are
	       passed to sv_fetchsv.

		       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_flags
	       Return the integer value of an SV, doing any necessary string conversion.  If
	       flags includes SV_GMAGIC, does an mg_get() first.  Normally used via the
	       "SvIV(sv)" and "SvIVx(sv)" macros.

		       IV      sv_2iv_flags(SV* sv, I32 flags)

       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_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_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 neces-
	       sary.  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_2uv_flags
	       Return the unsigned integer value of an SV, doing any necessary string conversion.
	       If flags includes SV_GMAGIC, does an mg_get() first.  Normally used via the
	       "SvUV(sv)" and "SvUVx(sv)" macros.

		       UV      sv_2uv_flags(SV* sv, I32 flags)

       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_catpvs
	       Like "sv_catpvn", but takes a literal string instead of a string/length pair.

		       void    sv_catpvs(SV* sv, const char* s)

       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 imple-
	       mented in terms of this function.

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

       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".

		       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 com-
	       parison 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 UTF8 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 nec-
	       essary. Handles 'get' magic.

		       void    sv_dec(SV* sv)

       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_flags
	       Undo various types of fakery on an SV: if the PV is a shared string, make a pri-
	       vate 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 nec-
	       essary. 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_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 particu-
	       lar, 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_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_pvbyten_force
	       The backend for the "SvPVbytex_force" macro. Always use the macro instead.

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

       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_pvutf8n_force
	       The backend for the "SvPVutf8x_force" macro. 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 tar-
	       get 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_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 han-
	       dle '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_setpvs
	       Like "sv_setpvn", but takes a literal string instead of a string/length pair.

		       void    sv_setpvs(SV* sv, const char* s)

       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
	       "NULL" 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
	       "NULL" 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
	       "NULL" 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 indi-
	       cates the package for the blessing.  Set "classname" to "NULL" to avoid the bless-
	       ing.  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 "class-
	       name" to "NULL" 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 imple-
	       mented in terms of this function.

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

	       This is the primary function for copying scalars, and most other copy-ish func-
	       tions 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_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_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_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 gener-
	       ally want to use the "SvUPGRADE" macro wrapper. See also "svtype".

		       bool    sv_upgrade(SV* sv, U32 mt)

       sv_usepvn_flags
	       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.  By default this function will realloc (i.e. move) the memory
	       pointed to by "ptr", so that pointer should not be freed or used by the programmer
	       after giving it to sv_usepvn, and neither should any pointers from "behind" that
	       pointer (e.g. ptr + 1) be used.

	       If "flags" & SV_SMAGIC is true, will call SvSETMAGIC. If "flags" & SV_HAS_TRAIL-
	       ING_NUL is true, then "ptr[len]" must be NUL, and the realloc will be skipped.
	       (i.e. the buffer is actually at least 1 byte longer than "len", and already meets
	       the requirements for storing in "SvPVX")

		       void    sv_usepvn_flags(SV* sv, char* ptr, STRLEN len, U32 flags)

       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_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/uni-
	       code/reports/tr21/ (Case Mappings).

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

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

	       The flags argument can have UNI_DISPLAY_ISPRINT set to display isPRINT()able char-
	       acters as themselves, UNI_DISPLAY_BACKSLASH to display the \\[nrfta\\] as the
	       backslashed versions (like '\n') (UNI_DISPLAY_BACKSLASH is preferred over UNI_DIS-
	       PLAY_ISPRINT for \\).  UNI_DISPLAY_QQ (and its alias UNI_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 ref-
	       erence, nothing is done to the sv.  If the encoding is not an "Encode::XS" Encod-
	       ing 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 SWASHNEW, 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
	       flags

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

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

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

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

	       If "s" does not point to a well-formed UTF-8 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 buf-
	       fer.

		       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 charac-
	       ter 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.

	       If you need a copy of the string, see "bytes_from_utf8".

	       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 con-
	       structor.  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 han-
	       dled automatically by "xsubpp" by calling "dXSARGS".

			       dAXMARK;

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

			       dITEMS;

       dUNDERBAR
	       Sets up the "padoff_du" variable for an XSUB that wishes to use "UNDERBAR".

			       dUNDERBAR;

       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

       UNDERBAR
	       The SV* corresponding to the $_ variable. Works even if there is a lexical $_ in
	       scope. (Lexical $_ is available in perl 5.9.2 and later)

       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
	       "NULL" to croak():

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

		       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, Spi-
       der Boardman, Ulrich Pfeifer, Stephen McCamant, and Gurusamy Sarathy.

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

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

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

perl v5.8.9				    2007-11-17				       PERLAPI(1)


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