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

NAME
       perlapi - autogenerated documentation for the perl public API

DESCRIPTION
       This file contains the documentation of the perl public API generated
       by embed.pl, specifically a listing of functions, macros, flags, and
       variables that may be used by extension writers.	 At the end is a list
       of functions which have yet to be documented.  The interfaces of those
       are subject to change without notice.  Any functions not listed here
       are not part of the public API, and should not be used by extension
       writers at all.	For these reasons, 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.

       Perl was originally written to handle US-ASCII only (that is characters
       whose ordinal numbers are in the range 0 - 127).	 And documentation and
       comments may still use the term ASCII, when sometimes in fact the
       entire range from 0 - 255 is meant.

       Note that Perl can be compiled and run under EBCDIC (See perlebcdic) or
       ASCII.  Most of the documentation (and even comments in the code)
       ignore the EBCDIC possibility.  For almost all purposes the differences
       are transparent.	 As an example, under EBCDIC, instead of UTF-8, UTF-
       EBCDIC is used to encode Unicode strings, and so whenever this
       documentation refers to "utf8" (and variants of that name, including in
       function names), it also (essentially transparently) means
       "UTF-EBCDIC".  But the ordinals of characters differ between ASCII,
       EBCDIC, and the UTF- encodings, and a string encoded in UTF-EBCDIC may
       occupy more bytes than in UTF-8.

       Also, on some EBCDIC machines, functions that are documented as
       operating on US-ASCII (or Basic Latin in Unicode terminology) may in
       fact operate on all 256 characters in the EBCDIC range, not just the
       subset corresponding to US-ASCII.

       The listing below 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. See perlcall for a usage example.

		       U32     GIMME_V

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

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

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

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

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

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

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

		       int     AvFILL(AV* av)

       av_clear
	       Clears an array, making it empty.  Does not free the memory the
	       av uses to store its list of scalars.  If any destructors are
	       triggered as a result, the av itself may be freed when this
	       function returns.

	       Perl equivalent: "@myarray = ();".

		       void    av_clear(AV *av)

       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, makes the
	       element mortal, and returns it.	If "flags" equals "G_DISCARD",
	       the element is freed and null is returned.  Perl equivalent:
	       "my $elem = delete($myarray[$idx]);" for the non-"G_DISCARD"
	       version and a void-context "delete($myarray[$idx]);" for the
	       "G_DISCARD" version.

		       SV*     av_delete(AV *av, 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.

	       Perl equivalent: "exists($myarray[$key])".

		       bool    av_exists(AV *av, I32 key)

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

		       void    av_extend(AV *av, I32 key)

       av_fetch
	       Returns the SV at the specified index in the array.  The "key"
	       is the index.  If lval is true, you are guaranteed to get a
	       real SV back (in case it wasn't real before), which you can
	       then modify.  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.

	       The rough perl equivalent is $myarray[$idx].

		       SV**    av_fetch(AV *av, 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 *av, 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.

	       The Perl equivalent for this is $#myarray.

		       I32     av_len(AV *av)

       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.

	       Perl equivalent: "my @new_array = ($scalar1, $scalar2,
	       $scalar3...);"

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

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

	       Perl equivalent: "pop(@myarray);"

		       SV*     av_pop(AV *av)

       av_push Pushes an SV onto the end of the array.	The array will grow
	       automatically to accommodate the addition.  This takes
	       ownership of one reference count.

	       Perl equivalent: "push @myarray, $elem;".

		       void    av_push(AV *av, SV *val)

       av_shift
	       Shifts an SV off the beginning of the array.  Returns
	       &PL_sv_undef if the array is empty.

	       Perl equivalent: "shift(@myarray);"

		       SV*     av_shift(AV *av)

       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 "SV*" that was stored there (= "val")).

	       Note that the caller is responsible for suitably incrementing
	       the reference count of "val" before the call, and decrementing
	       it if the function returned NULL.

	       Approximate Perl equivalent: "$myarray[$key] = $val;".

	       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 *av, I32 key, SV *val)

       av_undef
	       Undefines the array.  Frees the memory used by the av to store
	       its list of scalars.  If any destructors are triggered as a
	       result, the av itself may be freed.

		       void    av_undef(AV *av)

       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.

	       Perl equivalent: "unshift @myarray, ( (undef) x $n );"

		       void    av_unshift(AV *av, I32 num)

       get_av  Returns the AV of the specified Perl global or package array
	       with the given name (so it won't work on lexical variables).
	       "flags" are passed to "gv_fetchpv". If "GV_ADD" is set and the
	       Perl variable does not exist then it will be created.  If
	       "flags" is zero and the variable does not exist then NULL is
	       returned.

	       Perl equivalent: "@{"$name"}".

	       NOTE: the perl_ form of this function is deprecated.

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

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

	       Perl equivalent: "my @array;".

		       AV*     newAV()

       sortsv  Sort an array. Here is an example:

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

	       Currently this always uses mergesort. See sortsv_flags for a
	       more flexible routine.

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

       sortsv_flags
	       Sort an array, with various options.

		       void    sortsv_flags(SV** array, size_t num_elts,
					    SVCOMPARE_t cmp, U32 flags)

Callback Functions
       call_argv
	       Performs a callback to the specified named and package-scoped
	       Perl subroutine with "argv" (a NULL-terminated array of
	       strings) as arguments. See perlcall.

	       Approximate Perl equivalent: "&{"$sub_name"}(@$argv)".

	       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. It supports the same
	       flags as "call_sv", with the obvious exception of G_EVAL. See
	       perlcall.

	       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 case changing
       toLOWER Converts the specified character to lowercase in the platform's
	       native character set, if possible; otherwise returns the input
	       character itself.

		       char    toLOWER(char ch)

       toUPPER Converts the specified character to uppercase in the platform's
	       native character set, if possible; otherwise returns the input
	       character itself.

		       char    toUPPER(char ch)

Character classes
       There are three variants for all the functions in this section.	The
       base ones operate using the character set of the platform Perl is
       running on.  The ones with an "_A" suffix operate on the ASCII
       character set, and the ones with an "_L1" suffix operate on the full
       Latin1 character set.  All are unaffected by locale and by "use bytes".

       For ASCII platforms, the base function with no suffix and the one with
       the "_A" suffix are identical.  The function with the "_L1" suffix
       imposes the Latin-1 character set onto the platform.  That is, the code
       points that are ASCII are unaffected, since ASCII is a subset of
       Latin-1.	 But the non-ASCII code points are treated as if they are
       Latin-1 characters.  For example, "isSPACE_L1()" will return true when
       called with the code point 0xA0, which is the Latin-1 NO-BREAK SPACE.

       For EBCDIC platforms, the base function with no suffix and the one with
       the "_L1" suffix should be identical, since, as of this writing, the
       EBCDIC code pages that Perl knows about all are equivalent to Latin-1.
       The function that ends in an "_A" suffix will not return true unless
       the specified character also has an ASCII equivalent.

       isALPHA Returns a boolean indicating whether the specified character is
	       an alphabetic character in the platform's native character set.
	       See the top of this section for an explanation of variants
	       "isALPHA_A" and "isALPHA_L1".

		       bool    isALPHA(char ch)

       isASCII Returns a boolean indicating whether the specified character is
	       one of the 128 characters in the ASCII character set.  On non-
	       ASCII platforms, it is if this character corresponds to an
	       ASCII character.	 Variants "isASCII_A()" and "isASCII_L1()" are
	       identical to "isASCII()".

		       bool    isASCII(char ch)

       isDIGIT Returns a boolean indicating whether the specified character is
	       a digit in the platform's native character set.	Variants
	       "isDIGIT_A" and "isDIGIT_L1" are identical to "isDIGIT".

		       bool    isDIGIT(char ch)

       isLOWER Returns a boolean indicating whether the specified character is
	       a lowercase character in the platform's native character set.
	       See the top of this section for an explanation of variants
	       "isLOWER_A" and "isLOWER_L1".

		       bool    isLOWER(char ch)

       isOCTAL Returns a boolean indicating whether the specified character is
	       an octal digit, [0-7] in the platform's native character set.
	       Variants "isOCTAL_A" and "isOCTAL_L1" are identical to
	       "isOCTAL".

		       bool    isOCTAL(char ch)

       isSPACE Returns a boolean indicating whether the specified character is
	       a whitespace character in the platform's native character set.
	       This is the same as what "\s" matches in a regular expression.
	       See the top of this section for an explanation of variants
	       "isSPACE_A" and "isSPACE_L1".

		       bool    isSPACE(char ch)

       isUPPER Returns a boolean indicating whether the specified character is
	       an uppercase character in the platform's native character set.
	       See the top of this section for an explanation of variants
	       "isUPPER_A" and "isUPPER_L1".

		       bool    isUPPER(char ch)

       isWORDCHAR
	       Returns a boolean indicating whether the specified character is
	       a character that is any of: alphabetic, numeric, or an
	       underscore.  This is the same as what "\w" matches in a regular
	       expression.  "isALNUM()" is a synonym provided for backward
	       compatibility.  Note that it does not have the standard C
	       language meaning of alphanumeric, since it matches an
	       underscore and the standard meaning does not.  See the top of
	       this section for an explanation of variants "isWORDCHAR_A" and
	       "isWORDCHAR_L1".

		       bool    isWORDCHAR(char ch)

       isXDIGIT
	       Returns a boolean indicating whether the specified character is
	       a hexadecimal digit, [0-9A-Fa-f].  Variants "isXDIGIT_A()" and
	       "isXDIGIT_L1()" are identical to "isXDIGIT()".

		       bool    isXDIGIT(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
	       separate perl interpreter and then throw it away and return to
	       the original one, you don't need to do anything.

		       PerlInterpreter* perl_clone(
					    PerlInterpreter *proto_perl,
					    UV flags
					)

Compile-time scope hooks
       BhkDISABLE
	       Temporarily disable an entry in this BHK structure, by clearing
	       the appropriate flag. which is a preprocessor token indicating
	       which entry to disable.

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

		       void    BhkDISABLE(BHK *hk, which)

       BhkENABLE
	       Re-enable an entry in this BHK structure, by setting the
	       appropriate flag. which is a preprocessor token indicating
	       which entry to enable.  This will assert (under -DDEBUGGING) if
	       the entry doesn't contain a valid pointer.

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

		       void    BhkENABLE(BHK *hk, which)

       BhkENTRY_set
	       Set an entry in the BHK structure, and set the flags to
	       indicate it is valid. which is a preprocessing token indicating
	       which entry to set.  The type of ptr depends on the entry.

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

		       void    BhkENTRY_set(BHK *hk, which, void *ptr)

       blockhook_register
	       Register a set of hooks to be called when the Perl lexical
	       scope changes at compile time. See "Compile-time scope hooks"
	       in perlguts.

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

	       NOTE: this function must be explicitly called as
	       Perl_blockhook_register with an aTHX_ parameter.

		       void    Perl_blockhook_register(pTHX_ BHK *hk)

COP Hint Hashes
       cophh_2hv
	       Generates and returns a standard Perl hash representing the
	       full set of key/value pairs in the cop hints hash cophh.	 flags
	       is currently unused and must be zero.

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

		       HV *    cophh_2hv(const COPHH *cophh, U32 flags)

       cophh_copy
	       Make and return a complete copy of the cop hints hash cophh.

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

		       COPHH * cophh_copy(COPHH *cophh)

       cophh_delete_pv
	       Like "cophh_delete_pvn", but takes a nul-terminated string
	       instead of a string/length pair.

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

		       COPHH * cophh_delete_pv(const COPHH *cophh,
					       const char *key, U32 hash,
					       U32 flags)

       cophh_delete_pvn
	       Delete a key and its associated value from the cop hints hash
	       cophh, and returns the modified hash.  The returned hash
	       pointer is in general not the same as the hash pointer that was
	       passed in.  The input hash is consumed by the function, and the
	       pointer to it must not be subsequently used.  Use "cophh_copy"
	       if you need both hashes.

	       The key is specified by keypv and keylen.  If flags has the
	       "COPHH_KEY_UTF8" bit set, the key octets are interpreted as
	       UTF-8, otherwise they are interpreted as Latin-1.  hash is a
	       precomputed hash of the key string, or zero if it has not been
	       precomputed.

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

		       COPHH * cophh_delete_pvn(COPHH *cophh,
						const char *keypv,
						STRLEN keylen, U32 hash,
						U32 flags)

       cophh_delete_pvs
	       Like "cophh_delete_pvn", but takes a literal string instead of
	       a string/length pair, and no precomputed hash.

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

		       COPHH * cophh_delete_pvs(const COPHH *cophh,
						const char *key, U32 flags)

       cophh_delete_sv
	       Like "cophh_delete_pvn", but takes a Perl scalar instead of a
	       string/length pair.

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

		       COPHH * cophh_delete_sv(const COPHH *cophh, SV *key,
					       U32 hash, U32 flags)

       cophh_fetch_pv
	       Like "cophh_fetch_pvn", but takes a nul-terminated string
	       instead of a string/length pair.

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

		       SV *    cophh_fetch_pv(const COPHH *cophh,
					      const char *key, U32 hash,
					      U32 flags)

       cophh_fetch_pvn
	       Look up the entry in the cop hints hash cophh with the key
	       specified by keypv and keylen.  If flags has the
	       "COPHH_KEY_UTF8" bit set, the key octets are interpreted as
	       UTF-8, otherwise they are interpreted as Latin-1.  hash is a
	       precomputed hash of the key string, or zero if it has not been
	       precomputed.  Returns a mortal scalar copy of the value
	       associated with the key, or &PL_sv_placeholder if there is no
	       value associated with the key.

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

		       SV *    cophh_fetch_pvn(const COPHH *cophh,
					       const char *keypv,
					       STRLEN keylen, U32 hash,
					       U32 flags)

       cophh_fetch_pvs
	       Like "cophh_fetch_pvn", but takes a literal string instead of a
	       string/length pair, and no precomputed hash.

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

		       SV *    cophh_fetch_pvs(const COPHH *cophh,
					       const char *key, U32 flags)

       cophh_fetch_sv
	       Like "cophh_fetch_pvn", but takes a Perl scalar instead of a
	       string/length pair.

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

		       SV *    cophh_fetch_sv(const COPHH *cophh, SV *key,
					      U32 hash, U32 flags)

       cophh_free
	       Discard the cop hints hash cophh, freeing all resources
	       associated with it.

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

		       void    cophh_free(COPHH *cophh)

       cophh_new_empty
	       Generate and return a fresh cop hints hash containing no
	       entries.

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

		       COPHH * cophh_new_empty()

       cophh_store_pv
	       Like "cophh_store_pvn", but takes a nul-terminated string
	       instead of a string/length pair.

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

		       COPHH * cophh_store_pv(const COPHH *cophh,
					      const char *key, U32 hash,
					      SV *value, U32 flags)

       cophh_store_pvn
	       Stores a value, associated with a key, in the cop hints hash
	       cophh, and returns the modified hash.  The returned hash
	       pointer is in general not the same as the hash pointer that was
	       passed in.  The input hash is consumed by the function, and the
	       pointer to it must not be subsequently used.  Use "cophh_copy"
	       if you need both hashes.

	       The key is specified by keypv and keylen.  If flags has the
	       "COPHH_KEY_UTF8" bit set, the key octets are interpreted as
	       UTF-8, otherwise they are interpreted as Latin-1.  hash is a
	       precomputed hash of the key string, or zero if it has not been
	       precomputed.

	       value is the scalar value to store for this key.	 value is
	       copied by this function, which thus does not take ownership of
	       any reference to it, and later changes to the scalar will not
	       be reflected in the value visible in the cop hints hash.
	       Complex types of scalar will not be stored with referential
	       integrity, but will be coerced to strings.

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

		       COPHH * cophh_store_pvn(COPHH *cophh, const char *keypv,
					       STRLEN keylen, U32 hash,
					       SV *value, U32 flags)

       cophh_store_pvs
	       Like "cophh_store_pvn", but takes a literal string instead of a
	       string/length pair, and no precomputed hash.

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

		       COPHH * cophh_store_pvs(const COPHH *cophh,
					       const char *key, SV *value,
					       U32 flags)

       cophh_store_sv
	       Like "cophh_store_pvn", but takes a Perl scalar instead of a
	       string/length pair.

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

		       COPHH * cophh_store_sv(const COPHH *cophh, SV *key,
					      U32 hash, SV *value, U32 flags)

COP Hint Reading
       cop_hints_2hv
	       Generates and returns a standard Perl hash representing the
	       full set of hint entries in the cop cop.	 flags is currently
	       unused and must be zero.

		       HV *    cop_hints_2hv(const COP *cop, U32 flags)

       cop_hints_fetch_pv
	       Like "cop_hints_fetch_pvn", but takes a nul-terminated string
	       instead of a string/length pair.

		       SV *    cop_hints_fetch_pv(const COP *cop,
						  const char *key, U32 hash,
						  U32 flags)

       cop_hints_fetch_pvn
	       Look up the hint entry in the cop cop with the key specified by
	       keypv and keylen.  If flags has the "COPHH_KEY_UTF8" bit set,
	       the key octets are interpreted as UTF-8, otherwise they are
	       interpreted as Latin-1.	hash is a precomputed hash of the key
	       string, or zero if it has not been precomputed.	Returns a
	       mortal scalar copy of the value associated with the key, or
	       &PL_sv_placeholder if there is no value associated with the
	       key.

		       SV *    cop_hints_fetch_pvn(const COP *cop,
						   const char *keypv,
						   STRLEN keylen, U32 hash,
						   U32 flags)

       cop_hints_fetch_pvs
	       Like "cop_hints_fetch_pvn", but takes a literal string instead
	       of a string/length pair, and no precomputed hash.

		       SV *    cop_hints_fetch_pvs(const COP *cop,
						   const char *key, U32 flags)

       cop_hints_fetch_sv
	       Like "cop_hints_fetch_pvn", but takes a Perl scalar instead of
	       a string/length pair.

		       SV *    cop_hints_fetch_sv(const COP *cop, SV *key,
						  U32 hash, U32 flags)

Custom Operators
       custom_op_register
	       Register a custom op. See "Custom Operators" in perlguts.

	       NOTE: this function must be explicitly called as
	       Perl_custom_op_register with an aTHX_ parameter.

		       void    Perl_custom_op_register(pTHX_
						       Perl_ppaddr_t ppaddr,
						       const XOP *xop)

       custom_op_xop
	       Return the XOP structure for a given custom op. This function
	       should be considered internal to OP_NAME and the other access
	       macros: use them instead.

	       NOTE: this function must be explicitly called as
	       Perl_custom_op_xop with an aTHX_ parameter.

		       const XOP * Perl_custom_op_xop(pTHX_ const OP *o)

       XopDISABLE
	       Temporarily disable a member of the XOP, by clearing the
	       appropriate flag.

		       void    XopDISABLE(XOP *xop, which)

       XopENABLE
	       Reenable a member of the XOP which has been disabled.

		       void    XopENABLE(XOP *xop, which)

       XopENTRY
	       Return a member of the XOP structure. which is a cpp token
	       indicating which entry to return. If the member is not set this
	       will return a default value. The return type depends on which.

			       XopENTRY(XOP *xop, which)

       XopENTRY_set
	       Set a member of the XOP structure. which is a cpp token
	       indicating which entry to set. See "Custom Operators" in
	       perlguts for details about the available members and how they
	       are used.

		       void    XopENTRY_set(XOP *xop, which, value)

       XopFLAGS
	       Return the XOP's flags.

		       U32     XopFLAGS(XOP *xop)

CV Manipulation Functions
       CvSTASH Returns the stash of the CV. A stash is the symbol table hash,
	       containing the package-scoped variables in the package where
	       the subroutine was defined.  For more information, see
	       perlguts.

	       This also has a special use with XS AUTOLOAD subs.  See
	       "Autoloading with XSUBs" in perlguts.

		       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_fetchpvn_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_clone
	       Clone a CV, making a lexical closure.  proto supplies the
	       prototype of the function: its code, pad structure, and other
	       attributes.  The prototype is combined with a capture of outer
	       lexicals to which the code refers, which are taken from the
	       currently-executing instance of the immediately surrounding
	       code.

		       CV *    cv_clone(CV *proto)

       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)

       find_rundefsv
	       Find and return the variable that is named $_ in the lexical
	       scope of the currently-executing function.  This may be a
	       lexical $_, or will otherwise be the global one.

		       SV *    find_rundefsv()

       find_rundefsvoffset
	       Find the position of the lexical $_ in the pad of the
	       currently-executing function.  Returns the offset in the
	       current pad, or "NOT_IN_PAD" if there is no lexical $_ in scope
	       (in which case the global one should be used instead).
	       "find_rundefsv" is likely to be more convenient.

	       NOTE: the perl_ form of this function is deprecated.

		       PADOFFSET find_rundefsvoffset()

       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 and not NULL, 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".	They must be
	       terminated with a final NULL pointer.  Note that this list can
	       only be omitted when the PERL_LOADMOD_NOIMPORT flag has been
	       used.  Otherwise at least a single NULL pointer to designate
	       the default import list is required.

	       The reference count for each specified "SV*" parameter is
	       decremented.

		       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()

       pad_add_anon
	       Allocates a place in the currently-compiling pad (via
	       "pad_alloc") for an anonymous function that is lexically scoped
	       inside the currently-compiling function.	 The function func is
	       linked into the pad, and its "CvOUTSIDE" link to the outer
	       scope is weakened to avoid a reference loop.

	       optype should be an opcode indicating the type of operation
	       that the pad entry is to support.  This doesn't affect
	       operational semantics, but is used for debugging.

		       PADOFFSET pad_add_anon(CV *func, I32 optype)

       pad_add_name_pv
	       Exactly like "pad_add_name_pvn", but takes a nul-terminated
	       string instead of a string/length pair.

		       PADOFFSET pad_add_name_pv(const char *name, U32 flags,
						 HV *typestash, HV *ourstash)

       pad_add_name_pvn
	       Allocates a place in the currently-compiling pad for a named
	       lexical variable.  Stores the name and other metadata in the
	       name part of the pad, and makes preparations to manage the
	       variable's lexical scoping.  Returns the offset of the
	       allocated pad slot.

	       namepv/namelen specify the variable's name, including leading
	       sigil.  If typestash is non-null, the name is for a typed
	       lexical, and this identifies the type.  If ourstash is non-
	       null, it's a lexical reference to a package variable, and this
	       identifies the package.	The following flags can be OR'ed
	       together:

		   padadd_OUR	       redundantly specifies if it's a package var
		   padadd_STATE	       variable will retain value persistently
		   padadd_NO_DUP_CHECK skip check for lexical shadowing

		       PADOFFSET pad_add_name_pvn(const char *namepv,
						  STRLEN namelen, U32 flags,
						  HV *typestash, HV *ourstash)

       pad_add_name_sv
	       Exactly like "pad_add_name_pvn", but takes the name string in
	       the form of an SV instead of a string/length pair.

		       PADOFFSET pad_add_name_sv(SV *name, U32 flags,
						 HV *typestash, HV *ourstash)

       pad_alloc
	       Allocates a place in the currently-compiling pad, returning the
	       offset of the allocated pad slot.  No name is initially
	       attached to the pad slot.  tmptype is a set of flags indicating
	       the kind of pad entry required, which will be set in the value
	       SV for the allocated pad entry:

		   SVs_PADMY	named lexical variable ("my", "our", "state")
		   SVs_PADTMP	unnamed temporary store

	       optype should be an opcode indicating the type of operation
	       that the pad entry is to support.  This doesn't affect
	       operational semantics, but is used for debugging.

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

		       PADOFFSET pad_alloc(I32 optype, U32 tmptype)

       pad_compname_type
	       Looks up the type of the lexical variable at position po in the
	       currently-compiling pad.	 If the variable is typed, the stash
	       of the class to which it is typed is returned.  If not, "NULL"
	       is returned.

		       HV *    pad_compname_type(PADOFFSET po)

       pad_findmy_pv
	       Exactly like "pad_findmy_pvn", but takes a nul-terminated
	       string instead of a string/length pair.

		       PADOFFSET pad_findmy_pv(const char *name, U32 flags)

       pad_findmy_pvn
	       Given the name of a lexical variable, find its position in the
	       currently-compiling pad.	 namepv/namelen specify the variable's
	       name, including leading sigil.  flags is reserved and must be
	       zero.  If it is not in the current pad but appears in the pad
	       of any lexically enclosing scope, then a pseudo-entry for it is
	       added in the current pad.  Returns the offset in the current
	       pad, or "NOT_IN_PAD" if no such lexical is in scope.

		       PADOFFSET pad_findmy_pvn(const char *namepv,
						STRLEN namelen, U32 flags)

       pad_findmy_sv
	       Exactly like "pad_findmy_pvn", but takes the name string in the
	       form of an SV instead of a string/length pair.

		       PADOFFSET pad_findmy_sv(SV *name, U32 flags)

       pad_setsv
	       Set the value at offset po in the current (compiling or
	       executing) pad.	Use the macro PAD_SETSV() rather than calling
	       this function directly.

		       void    pad_setsv(PADOFFSET po, SV *sv)

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

		       SV *    pad_sv(PADOFFSET po)

       pad_tidy
	       Tidy up a pad at the end of compilation of the code to which it
	       belongs.	 Jobs performed here are: remove most stuff from the
	       pads of anonsub prototypes; give it a @_; mark temporaries as
	       such.  type indicates the kind of subroutine:

		   padtidy_SUB	      ordinary subroutine
		   padtidy_SUBCLONE   prototype for lexical closure
		   padtidy_FORMAT     format

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

		       void    pad_tidy(padtidy_type type)

       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 *my_perl)

       perl_destruct
	       Shuts down a Perl interpreter.  See perlembed.

		       int     perl_destruct(PerlInterpreter *my_perl)

       perl_free
	       Releases a Perl interpreter.  See perlembed.

		       void    perl_free(PerlInterpreter *my_perl)

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

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

       perl_run
	       Tells a Perl interpreter to run.	 See perlembed.

		       int     perl_run(PerlInterpreter *my_perl)

       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, const 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 contain 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 if
	       PERL_PV_ESCAPE_NONASCII is set, only chars above 127 will be
	       escaped using this style; otherwise, only chars above 255 will
	       be so escaped; other non printable chars will use octal or
	       common escaped patterns like "\n". Otherwise, 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, regardless of max. If the output is
	       to be in hex, then it will be returned as a plain hex sequence.
	       Thus the output will either be a single char, an octal escape
	       sequence, a special escape like "\n" or a hex value.

	       If PERL_PV_ESCAPE_RE is set then the escape char used will be a
	       '%' and not a '\\'. This is because regexes very often contain
	       backslashed sequences, whereas '%' is not a particularly common
	       character in patterns.

	       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 ellipses.

	       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_ELLIPSES flag is set and not all
	       characters in string were output then an ellipsis "..." will be
	       appended to the string. Note that this happens 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 ellipses.

	       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
       custom_op_desc
	       Return the description of a given custom op. This was once used
	       by the OP_DESC macro, but is no longer: it has only been kept
	       for compatibility, and should not be used.

		       const char * custom_op_desc(const OP *o)

       custom_op_name
	       Return the name for a given custom op. This was once used by
	       the OP_NAME macro, but is no longer: it has only been kept for
	       compatibility, and should not be used.

		       const char * custom_op_name(const OP *o)

       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, const char *pat,
					const 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 *dsv, SV *ssv)

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

		       void    sv_force_normal(SV *sv)

       sv_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 *lp)

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

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

       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 *lp)

       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(const char *pat, const char *patend,
					  const char *s, const char *strbeg,
					  const char *strend, char **new_s,
					  I32 ocnt, U32 flags)

Functions in file op.c
       op_contextualize
	       Applies a syntactic context to an op tree representing an
	       expression.  o is the op tree, and context must be "G_SCALAR",
	       "G_ARRAY", or "G_VOID" to specify the context to apply.	The
	       modified op tree is returned.

		       OP *    op_contextualize(OP *o, I32 context)

Functions in file perl.h
       PERL_SYS_INIT
	       Provides system-specific tune up of the C runtime environment
	       necessary to run Perl interpreters. This should be called only
	       once, before creating any Perl interpreters.

		       void    PERL_SYS_INIT(int argc, char** argv)

       PERL_SYS_INIT3
	       Provides system-specific tune up of the C runtime environment
	       necessary to run Perl interpreters. This should be called only
	       once, before creating any Perl interpreters.

		       void    PERL_SYS_INIT3(int argc, char** argv,
					      char** env)

       PERL_SYS_TERM
	       Provides system-specific clean up of the C runtime environment
	       after running Perl interpreters. This should be called only
	       once, after freeing any remaining Perl interpreters.

		       void    PERL_SYS_TERM()

Functions in file pp_ctl.c
       caller_cx
	       The XSUB-writer's equivalent of caller(). The returned
	       "PERL_CONTEXT" structure can be interrogated to find all the
	       information returned to Perl by "caller". Note that XSUBs don't
	       get a stack frame, so "caller_cx(0, NULL)" will return
	       information for the immediately-surrounding Perl code.

	       This function skips over the automatic calls to &DB::sub made
	       on the behalf of the debugger. If the stack frame requested was
	       a sub called by "DB::sub", the return value will be the frame
	       for the call to "DB::sub", since that has the correct line
	       number/etc. for the call site. If dbcxp is non-"NULL", it will
	       be set to a pointer to the frame for the sub call itself.

		       const PERL_CONTEXT * caller_cx(
						I32 level,
						const PERL_CONTEXT **dbcxp
					    )

       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, const char *pat,
					const 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(const char *pat,
					    const char *patend, const char *s,
					    const char *strend, U32 flags)

Functions in file pp_sys.c
       setdefout
	       Sets PL_defoutgv, the default file handle for output, to the
	       passed in typeglob. As PL_defoutgv "owns" a reference on its
	       typeglob, the reference count of the passed in typeglob is
	       increased by one, and the reference count of the typeglob that
	       PL_defoutgv points to is decreased by one.

		       void    setdefout(GV* gv)

Functions in file utf8.h
       ibcmp_utf8
	       This is a synonym for (! foldEQ_utf8())

		       I32     ibcmp_utf8(const char *s1, char **pe1, UV l1,
					  bool u1, const char *s2, char **pe2,
					  UV l2, bool u2)

Functions in file util.h
       ibcmp   This is a synonym for (! foldEQ())

		       I32     ibcmp(const char* a, const char* b, I32 len)

       ibcmp_locale
	       This is a synonym for (! foldEQ_locale())

		       I32     ibcmp_locale(const char* a, const char* b,
					    I32 len)

Global Variables
       PL_check
	       Array, indexed by opcode, of functions that will be called for
	       the "check" phase of optree building during compilation of Perl
	       code.  For most (but not all) types of op, once the op has been
	       initially built and populated with child ops it will be
	       filtered through the check function referenced by the
	       appropriate element of this array.  The new op is passed in as
	       the sole argument to the check function, and the check function
	       returns the completed op.  The check function may (as the name
	       suggests) check the op for validity and signal errors.  It may
	       also initialise or modify parts of the ops, or perform more
	       radical surgery such as adding or removing child ops, or even
	       throw the op away and return a different op in its place.

	       This array of function pointers is a convenient place to hook
	       into the compilation process.  An XS module can put its own
	       custom check function in place of any of the standard ones, to
	       influence the compilation of a particular type of op.  However,
	       a custom check function must never fully replace a standard
	       check function (or even a custom check function from another
	       module).	 A module modifying checking must instead wrap the
	       preexisting check function.  A custom check function must be
	       selective about when to apply its custom behaviour.  In the
	       usual case where it decides not to do anything special with an
	       op, it must chain the preexisting op function.  Check functions
	       are thus linked in a chain, with the core's base checker at the
	       end.

	       For thread safety, modules should not write directly to this
	       array.  Instead, use the function "wrap_op_checker".

       PL_keyword_plugin
	       Function pointer, pointing at a function used to handle
	       extended keywords.  The function should be declared as

		       int keyword_plugin_function(pTHX_
			       char *keyword_ptr, STRLEN keyword_len,
			       OP **op_ptr)

	       The function is called from the tokeniser, whenever a possible
	       keyword is seen.	 "keyword_ptr" points at the word in the
	       parser's input buffer, and "keyword_len" gives its length; it
	       is not null-terminated.	The function is expected to examine
	       the word, and possibly other state such as %^H, to decide
	       whether it wants to handle it as an extended keyword.  If it
	       does not, the function should return "KEYWORD_PLUGIN_DECLINE",
	       and the normal parser process will continue.

	       If the function wants to handle the keyword, it first must
	       parse anything following the keyword that is part of the syntax
	       introduced by the keyword.  See "Lexer interface" for details.

	       When a keyword is being handled, the plugin function must build
	       a tree of "OP" structures, representing the code that was
	       parsed.	The root of the tree must be stored in *op_ptr.	 The
	       function then returns a constant indicating the syntactic role
	       of the construct that it has parsed: "KEYWORD_PLUGIN_STMT" if
	       it is a complete statement, or "KEYWORD_PLUGIN_EXPR" if it is
	       an expression.  Note that a statement construct cannot be used
	       inside an expression (except via "do BLOCK" and similar), and
	       an expression is not a complete statement (it requires at least
	       a terminating semicolon).

	       When a keyword is handled, the plugin function may also have
	       (compile-time) side effects.  It may modify "%^H", define
	       functions, and so on.  Typically, if side effects are the main
	       purpose of a handler, it does not wish to generate any ops to
	       be included in the normal compilation.  In this case it is
	       still required to supply an op tree, but it suffices to
	       generate a single null op.

	       That's how the *PL_keyword_plugin function needs to behave
	       overall.	 Conventionally, however, one does not completely
	       replace the existing handler function.  Instead, take a copy of
	       "PL_keyword_plugin" before assigning your own function pointer
	       to it.  Your handler function should look for keywords that it
	       is interested in and handle those.  Where it is not interested,
	       it should call the saved plugin function, passing on the
	       arguments it received.  Thus "PL_keyword_plugin" actually
	       points at a chain of handler functions, all of which have an
	       opportunity to handle keywords, and only the last function in
	       the chain (built into the Perl core) will normally return
	       "KEYWORD_PLUGIN_DECLINE".

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

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 inlining, 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
	       Like "gv_fetchmeth_pvn", but lacks a flags parameter.

		       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" parameter.

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

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

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

       gv_fetchmeth_autoload
	       This is the old form of "gv_fetchmeth_pvn_autoload", which has
	       no flags parameter.

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

       gv_fetchmeth_pv
	       Exactly like "gv_fetchmeth_pvn", but takes a nul-terminated
	       string instead of a string/length pair.

		       GV*     gv_fetchmeth_pv(HV* stash, const char* name,
					       I32 level, U32 flags)

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

	       The argument "level" should be either 0 or -1.  If "level==0",
	       as a side-effect creates a glob with the given "name" in the
	       given "stash" which in the case of success contains an alias
	       for the subroutine, and sets up caching info for this glob.

	       Currently, the only significant value for "flags" is SVf_UTF8.

	       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_pvn(HV* stash, const char* name,
						STRLEN len, I32 level,
						U32 flags)

       gv_fetchmeth_pvn_autoload
	       Same as gv_fetchmeth_pvn(), 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.

	       Currently, the only significant value for "flags" is SVf_UTF8.

		       GV*     gv_fetchmeth_pvn_autoload(HV* stash,
							 const char* name,
							 STRLEN len, I32 level,
							 U32 flags)

       gv_fetchmeth_pv_autoload
	       Exactly like "gv_fetchmeth_pvn_autoload", but takes a nul-
	       terminated string instead of a string/length pair.

		       GV*     gv_fetchmeth_pv_autoload(HV* stash,
							const char* name,
							I32 level, U32 flags)

       gv_fetchmeth_sv
	       Exactly like "gv_fetchmeth_pvn", but takes the name string in
	       the form of an SV instead of a string/length pair.

		       GV*     gv_fetchmeth_sv(HV* stash, SV* namesv,
					       I32 level, U32 flags)

       gv_fetchmeth_sv_autoload
	       Exactly like "gv_fetchmeth_pvn_autoload", but takes the name
	       string in the form of an SV instead of a string/length pair.

		       GV*     gv_fetchmeth_sv_autoload(HV* stash, SV* namesv,
							I32 level, U32 flags)

       gv_init The old form of gv_init_pvn().  It does not work with UTF8
	       strings, as it has no flags parameter.  If the "multi"
	       parameter is set, the GV_ADDMULTI flag will be passed to
	       gv_init_pvn().

		       void    gv_init(GV* gv, HV* stash, const char* name,
				       STRLEN len, int multi)

       gv_init_pv
	       Same as gv_init_pvn(), but takes a nul-terminated string for
	       the name instead of separate char * and length parameters.

		       void    gv_init_pv(GV* gv, HV* stash, const char* name,
					  U32 flags)

       gv_init_pvn
	       Converts a scalar into a typeglob.  This is an incoercible
	       typeglob; assigning a reference to it will assign to one of its
	       slots, instead of overwriting it as happens with typeglobs
	       created by SvSetSV.  Converting any scalar that is SvOK() may
	       produce unpredictable results and is reserved for perl's
	       internal use.

	       "gv" is the scalar to be converted.

	       "stash" is the parent stash/package, if any.

	       "name" and "len" give the name.	The name must be unqualified;
	       that is, it must not include the package name.  If "gv" is a
	       stash element, it is the caller's responsibility to ensure that
	       the name passed to this function matches the name of the
	       element.	 If it does not match, perl's internal bookkeeping
	       will get out of sync.

	       "flags" can be set to SVf_UTF8 if "name" is a UTF8 string, or
	       the return value of SvUTF8(sv).	It can also take the
	       GV_ADDMULTI flag, which means to pretend that the GV has been
	       seen before (i.e., suppress "Used once" warnings).

		       void    gv_init_pvn(GV* gv, HV* stash, const char* name,
					   STRLEN len, U32 flags)

       gv_init_sv
	       Same as gv_init_pvn(), but takes an SV * for the name instead
	       of separate char * and length parameters.  "flags" is currently
	       unused.

		       void    gv_init_sv(GV* gv, HV* stash, SV* namesv,
					  U32 flags)

       gv_stashpv
	       Returns a pointer to the stash for a specified package.	Uses
	       "strlen" to determine 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_fetchpvn_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.

	       (deprecated - use "(AV *)NULL" instead)

       Nullch  Null character pointer. (No longer available when "PERL_CORE"
	       is defined.)

       Nullcv  Null CV pointer.

	       (deprecated - use "(CV *)NULL" instead)

       Nullhv  Null HV pointer.

	       (deprecated - use "(HV *)NULL" instead)

       Nullsv  Null SV pointer. (No longer available when "PERL_CORE" is
	       defined.)

Hash Manipulation Functions
       cop_fetch_label
	       Returns the label attached to a cop.  The flags pointer may be
	       set to "SVf_UTF8" or 0.

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

		       const char * cop_fetch_label(COP *const cop,
						    STRLEN *len, U32 *flags)

       cop_store_label
	       Save a label into a "cop_hints_hash". You need to set flags to
	       "SVf_UTF8" for a utf-8 label.

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

		       void    cop_store_label(COP *const cop,
					       const char *label, STRLEN len,
					       U32 flags)

       get_hv  Returns the HV of the specified Perl hash.  "flags" are passed
	       to "gv_fetchpv". If "GV_ADD" is set and the Perl variable does
	       not exist then it will be created.  If "flags" is zero and the
	       variable does not exist then NULL is returned.

	       NOTE: the perl_ form of this function is deprecated.

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

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

       HeHASH  Returns the computed hash stored in the hash entry.

		       U32     HeHASH(HE* he)

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

		       void*   HeKEY(HE* he)

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

		       STRLEN  HeKLEN(HE* he)

       HePV    Returns the key slot of the hash entry as a "char*" value,
	       doing any necessary dereferencing of possibly "SV*" keys.  The
	       length of the string is placed in "len" (this is a macro, so do
	       not use &len).  If you do not care about what the length of the
	       key is, you may use the global variable "PL_na", though this is
	       rather less efficient than using a local variable.  Remember
	       though, that hash keys in perl are free to contain embedded
	       nulls, so using "strlen()" or similar is not a good way to find
	       the length of hash keys. This is very similar to the "SvPV()"
	       macro described elsewhere in this document. 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 indicate 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)

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

		       SV*     HeVAL(HE* he)

       HvENAME Returns the effective name of a stash, or NULL if there is
	       none. The effective name represents a location in the symbol
	       table where this stash resides. It is updated automatically
	       when packages are aliased or deleted.  A stash that is no
	       longer in the symbol table has no effective name. This name is
	       preferable to "HvNAME" for use in MRO linearisations and isa
	       caches.

		       char*   HvENAME(HV* stash)

       HvENAMELEN
	       Returns the length of the stash's effective name.

		       STRLEN  HvENAMELEN(HV *stash)

       HvENAMEUTF8
	       Returns true if the effective name is in UTF8 encoding.

		       unsigned char HvENAMEUTF8(HV *stash)

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

		       char*   HvNAME(HV* stash)

       HvNAMELEN
	       Returns the length of the stash's name.

		       STRLEN  HvNAMELEN(HV *stash)

       HvNAMEUTF8
	       Returns true if the name is in UTF8 encoding.

		       unsigned char HvNAMEUTF8(HV *stash)

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

		       void    hv_assert(HV *hv)

       hv_clear
	       Frees the all the elements of a hash, leaving it empty.	The XS
	       equivalent of "%hash = ()".  See also "hv_undef".

	       If any destructors are triggered as a result, the hv itself may
	       be freed.

		       void    hv_clear(HV *hv)

       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 *hv)

       hv_copy_hints_hv
	       A specialised version of "newHVhv" for copying "%^H".  ohv must
	       be a pointer to a hash (which may have "%^H" magic, but should
	       be generally non-magical), or "NULL" (interpreted as an empty
	       hash).  The content of ohv is copied to a new hash, which has
	       the "%^H"-specific magic added to it.  A pointer to the new
	       hash is returned.

		       HV *    hv_copy_hints_hv(HV *ohv)

       hv_delete
	       Deletes a key/value pair in the hash.  The value's SV is
	       removed from the hash, made mortal, and returned to the caller.
	       The absolute value of "klen" is the length of the key.  If
	       "klen" is negative the key is assumed to be in UTF-8-encoded
	       Unicode.	 The "flags" value will normally be zero; if set to
	       G_DISCARD then NULL will be returned.  NULL will also be
	       returned if the key is not found.

		       SV*     hv_delete(HV *hv, 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, made mortal, and returned to the caller.	The
	       "flags" value will normally be zero; if set to G_DISCARD then
	       NULL will be returned.  NULL will also be returned if the key
	       is not found.  "hash" can be a valid precomputed hash value, or
	       0 to ask for it to be computed.

		       SV*     hv_delete_ent(HV *hv, SV *keysv, I32 flags,
					     U32 hash)

       hv_exists
	       Returns a boolean indicating whether the specified hash key
	       exists.	The absolute value of "klen" is the length of the key.
	       If "klen" is negative the key is assumed to be in UTF-8-encoded
	       Unicode.

		       bool    hv_exists(HV *hv, 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 *hv, SV *keysv, U32 hash)

       hv_fetch
	       Returns the SV which corresponds to the specified key in the
	       hash.  The absolute value of "klen" is the length of the key.
	       If "klen" is negative the key is assumed to be in UTF-8-encoded
	       Unicode.	 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 *hv, 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 "hv" 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 *hv, SV *keysv, I32 lval,
					    U32 hash)

       hv_fill Returns the number of hash buckets that happen to be in use.
	       This function is wrapped by the macro "HvFILL".

	       Previously this value was stored in the HV structure, rather
	       than being calculated on demand.

		       STRLEN  hv_fill(HV const *const hv)

       hv_iterinit
	       Prepares a starting point to traverse a hash table.  Returns
	       the number of keys in the hash (i.e. the same as
	       "HvUSEDKEYS(hv)").  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(hv)".

		       I32     hv_iterinit(HV *hv)

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

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

       hv_iterkeysv
	       Returns the key as an "SV*" from the current position of the
	       hash iterator.  The return value will always be a mortal copy
	       of the key.  Also see "hv_iterinit".

		       SV*     hv_iterkeysv(HE* entry)

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

	       You may call "hv_delete" or "hv_delete_ent" on the hash entry
	       that the iterator currently points to, without losing your
	       place or invalidating your iterator.  Note that in this case
	       the current entry is deleted from the hash with your iterator
	       holding the last reference to it.  Your iterator is flagged to
	       free the entry on the next call to "hv_iternext", so you must
	       not discard your iterator immediately else the entry will leak
	       - call "hv_iternext" to trigger the resource deallocation.

		       HE*     hv_iternext(HV *hv)

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

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

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

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

		       HE*     hv_iternext_flags(HV *hv, I32 flags)

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

		       SV*     hv_iterval(HV *hv, 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
	       the absolute value of "klen" is the length of the key.  If
	       "klen" is negative the key is assumed to be in UTF-8-encoded
	       Unicode.	 The "hash" parameter is the precomputed hash value;
	       if it is zero then Perl will compute it.

	       The return value will be NULL if the operation failed or if the
	       value did not need to be actually stored within the hash (as in
	       the case of tied hashes).  Otherwise it can be dereferenced to
	       get the original "SV*".	Note that the caller is responsible
	       for suitably incrementing the reference count of "val" before
	       the call, and decrementing it if the function returned NULL.
	       Effectively a successful hv_store takes ownership of one
	       reference to "val".  This is usually what you want; a newly
	       created SV has a reference count of one, so if all your code
	       does is create SVs then store them in a hash, hv_store will own
	       the only reference to the new SV, and your code doesn't need to
	       do anything further to tidy up.	hv_store is not implemented as
	       a call to hv_store_ent, and does not create a temporary SV for
	       the key, so if your key data is not already in SV form then use
	       hv_store in preference to hv_store_ent.

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

		       SV**    hv_store(HV *hv, 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 responsible for
	       suitably incrementing the reference count of "val" before the
	       call, and decrementing it if the function returned NULL.
	       Effectively a successful hv_store_ent takes ownership of one
	       reference to "val".  This is usually what you want; a newly
	       created SV has a reference count of one, so if all your code
	       does is create SVs then store them in a hash, hv_store will own
	       the only reference to the new SV, and your code doesn't need to
	       do anything further to tidy up.	Note that hv_store_ent only
	       reads the "key"; unlike "val" it does not take ownership of it,
	       so maintaining the correct reference count on "key" is entirely
	       the caller's responsibility.  hv_store is not implemented as a
	       call to hv_store_ent, and does not create a temporary SV for
	       the key, so if your key data is not already in SV form then use
	       hv_store in preference to hv_store_ent.

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

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

       hv_undef
	       Undefines the hash.  The XS equivalent of "undef(%hash)".

	       As well as freeing all the elements of the hash (like
	       hv_clear()), this also frees any auxiliary data and storage
	       associated with the hash.

	       If any destructors are triggered as a result, the hv itself may
	       be freed.

	       See also "hv_clear".

		       void    hv_undef(HV *hv)

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

		       HV*     newHV()

Hook manipulation
       wrap_op_checker
	       Puts a C function into the chain of check functions for a
	       specified op type.  This is the preferred way to manipulate the
	       "PL_check" array.  opcode specifies which type of op is to be
	       affected.  new_checker is a pointer to the C function that is
	       to be added to that opcode's check chain, and old_checker_p
	       points to the storage location where a pointer to the next
	       function in the chain will be stored.  The value of new_pointer
	       is written into the "PL_check" array, while the value
	       previously stored there is written to *old_checker_p.

	       "PL_check" is global to an entire process, and a module wishing
	       to hook op checking may find itself invoked more than once per
	       process, typically in different threads.	 To handle that
	       situation, this function is idempotent.	The location
	       *old_checker_p must initially (once per process) contain a null
	       pointer.	 A C variable of static duration (declared at file
	       scope, typically also marked "static" to give it internal
	       linkage) will be implicitly initialised appropriately, if it
	       does not have an explicit initialiser.  This function will only
	       actually modify the check chain if it finds *old_checker_p to
	       be null.	 This function is also thread safe on the small scale.
	       It uses appropriate locking to avoid race conditions in
	       accessing "PL_check".

	       When this function is called, the function referenced by
	       new_checker must be ready to be called, except for
	       *old_checker_p being unfilled.  In a threading situation,
	       new_checker may be called immediately, even before this
	       function has returned.  *old_checker_p will always be
	       appropriately set before new_checker is called.	If new_checker
	       decides not to do anything special with an op that it is given
	       (which is the usual case for most uses of op check hooking), it
	       must chain the check function referenced by *old_checker_p.

	       If you want to influence compilation of calls to a specific
	       subroutine, then use "cv_set_call_checker" rather than hooking
	       checking of all "entersub" ops.

		       void    wrap_op_checker(Optype opcode,
					       Perl_check_t new_checker,
					       Perl_check_t *old_checker_p)

Lexer interface
       lex_bufutf8
	       Indicates whether the octets in the lexer buffer
	       ("PL_parser->linestr") should be interpreted as the UTF-8
	       encoding of Unicode characters.	If not, they should be
	       interpreted as Latin-1 characters.  This is analogous to the
	       "SvUTF8" flag for scalars.

	       In UTF-8 mode, it is not guaranteed that the lexer buffer
	       actually contains valid UTF-8.  Lexing code must be robust in
	       the face of invalid encoding.

	       The actual "SvUTF8" flag of the "PL_parser->linestr" scalar is
	       significant, but not the whole story regarding the input
	       character encoding.  Normally, when a file is being read, the
	       scalar contains octets and its "SvUTF8" flag is off, but the
	       octets should be interpreted as UTF-8 if the "use utf8" pragma
	       is in effect.  During a string eval, however, the scalar may
	       have the "SvUTF8" flag on, and in this case its octets should
	       be interpreted as UTF-8 unless the "use bytes" pragma is in
	       effect.	This logic may change in the future; use this function
	       instead of implementing the logic yourself.

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

		       bool    lex_bufutf8()

       lex_discard_to
	       Discards the first part of the "PL_parser->linestr" buffer, up
	       to ptr.	The remaining content of the buffer will be moved, and
	       all pointers into the buffer updated appropriately.  ptr must
	       not be later in the buffer than the position of
	       "PL_parser->bufptr": it is not permitted to discard text that
	       has yet to be lexed.

	       Normally it is not necessarily to do this directly, because it
	       suffices to use the implicit discarding behaviour of
	       "lex_next_chunk" and things based on it.	 However, if a token
	       stretches across multiple lines, and the lexing code has kept
	       multiple lines of text in the buffer for that purpose, then
	       after completion of the token it would be wise to explicitly
	       discard the now-unneeded earlier lines, to avoid future multi-
	       line tokens growing the buffer without bound.

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

		       void    lex_discard_to(char *ptr)

       lex_grow_linestr
	       Reallocates the lexer buffer ("PL_parser->linestr") to
	       accommodate at least len octets (including terminating NUL).
	       Returns a pointer to the reallocated buffer.  This is necessary
	       before making any direct modification of the buffer that would
	       increase its length.  "lex_stuff_pvn" provides a more
	       convenient way to insert text into the buffer.

	       Do not use "SvGROW" or "sv_grow" directly on
	       "PL_parser->linestr"; this function updates all of the lexer's
	       variables that point directly into the buffer.

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

		       char *  lex_grow_linestr(STRLEN len)

       lex_next_chunk
	       Reads in the next chunk of text to be lexed, appending it to
	       "PL_parser->linestr".  This should be called when lexing code
	       has looked to the end of the current chunk and wants to know
	       more.  It is usual, but not necessary, for lexing to have
	       consumed the entirety of the current chunk at this time.

	       If "PL_parser->bufptr" is pointing to the very end of the
	       current chunk (i.e., the current chunk has been entirely
	       consumed), normally the current chunk will be discarded at the
	       same time that the new chunk is read in.	 If flags includes
	       "LEX_KEEP_PREVIOUS", the current chunk will not be discarded.
	       If the current chunk has not been entirely consumed, then it
	       will not be discarded regardless of the flag.

	       Returns true if some new text was added to the buffer, or false
	       if the buffer has reached the end of the input text.

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

		       bool    lex_next_chunk(U32 flags)

       lex_peek_unichar
	       Looks ahead one (Unicode) character in the text currently being
	       lexed.  Returns the codepoint (unsigned integer value) of the
	       next character, or -1 if lexing has reached the end of the
	       input text.  To consume the peeked character, use
	       "lex_read_unichar".

	       If the next character is in (or extends into) the next chunk of
	       input text, the next chunk will be read in.  Normally the
	       current chunk will be discarded at the same time, but if flags
	       includes "LEX_KEEP_PREVIOUS" then the current chunk will not be
	       discarded.

	       If the input is being interpreted as UTF-8 and a UTF-8 encoding
	       error is encountered, an exception is generated.

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

		       I32     lex_peek_unichar(U32 flags)

       lex_read_space
	       Reads optional spaces, in Perl style, in the text currently
	       being lexed.  The spaces may include ordinary whitespace
	       characters and Perl-style comments.  "#line" directives are
	       processed if encountered.  "PL_parser->bufptr" is moved past
	       the spaces, so that it points at a non-space character (or the
	       end of the input text).

	       If spaces extend into the next chunk of input text, the next
	       chunk will be read in.  Normally the current chunk will be
	       discarded at the same time, but if flags includes
	       "LEX_KEEP_PREVIOUS" then the current chunk will not be
	       discarded.

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

		       void    lex_read_space(U32 flags)

       lex_read_to
	       Consume text in the lexer buffer, from "PL_parser->bufptr" up
	       to ptr.	This advances "PL_parser->bufptr" to match ptr,
	       performing the correct bookkeeping whenever a newline character
	       is passed.  This is the normal way to consume lexed text.

	       Interpretation of the buffer's octets can be abstracted out by
	       using the slightly higher-level functions "lex_peek_unichar"
	       and "lex_read_unichar".

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

		       void    lex_read_to(char *ptr)

       lex_read_unichar
	       Reads the next (Unicode) character in the text currently being
	       lexed.  Returns the codepoint (unsigned integer value) of the
	       character read, and moves "PL_parser->bufptr" past the
	       character, or returns -1 if lexing has reached the end of the
	       input text.  To non-destructively examine the next character,
	       use "lex_peek_unichar" instead.

	       If the next character is in (or extends into) the next chunk of
	       input text, the next chunk will be read in.  Normally the
	       current chunk will be discarded at the same time, but if flags
	       includes "LEX_KEEP_PREVIOUS" then the current chunk will not be
	       discarded.

	       If the input is being interpreted as UTF-8 and a UTF-8 encoding
	       error is encountered, an exception is generated.

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

		       I32     lex_read_unichar(U32 flags)

       lex_start
	       Creates and initialises a new lexer/parser state object,
	       supplying a context in which to lex and parse from a new source
	       of Perl code.  A pointer to the new state object is placed in
	       "PL_parser".  An entry is made on the save stack so that upon
	       unwinding the new state object will be destroyed and the former
	       value of "PL_parser" will be restored.  Nothing else need be
	       done to clean up the parsing context.

	       The code to be parsed comes from line and rsfp.	line, if non-
	       null, provides a string (in SV form) containing code to be
	       parsed.	A copy of the string is made, so subsequent
	       modification of line does not affect parsing.  rsfp, if non-
	       null, provides an input stream from which code will be read to
	       be parsed.  If both are non-null, the code in line comes first
	       and must consist of complete lines of input, and rsfp supplies
	       the remainder of the source.

	       The flags parameter is reserved for future use.	Currently it
	       is only used by perl internally, so extensions should always
	       pass zero.

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

		       void    lex_start(SV *line, PerlIO *rsfp, U32 flags)

       lex_stuff_pv
	       Insert characters into the lexer buffer ("PL_parser->linestr"),
	       immediately after the current lexing point
	       ("PL_parser->bufptr"), reallocating the buffer if necessary.
	       This means that lexing code that runs later will see the
	       characters as if they had appeared in the input.	 It is not
	       recommended to do this as part of normal parsing, and most uses
	       of this facility run the risk of the inserted characters being
	       interpreted in an unintended manner.

	       The string to be inserted is represented by octets starting at
	       pv and continuing to the first nul.  These octets are
	       interpreted as either UTF-8 or Latin-1, according to whether
	       the "LEX_STUFF_UTF8" flag is set in flags.  The characters are
	       recoded for the lexer buffer, according to how the buffer is
	       currently being interpreted ("lex_bufutf8").  If it is not
	       convenient to nul-terminate a string to be inserted, the
	       "lex_stuff_pvn" function is more appropriate.

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

		       void    lex_stuff_pv(const char *pv, U32 flags)

       lex_stuff_pvn
	       Insert characters into the lexer buffer ("PL_parser->linestr"),
	       immediately after the current lexing point
	       ("PL_parser->bufptr"), reallocating the buffer if necessary.
	       This means that lexing code that runs later will see the
	       characters as if they had appeared in the input.	 It is not
	       recommended to do this as part of normal parsing, and most uses
	       of this facility run the risk of the inserted characters being
	       interpreted in an unintended manner.

	       The string to be inserted is represented by len octets starting
	       at pv.  These octets are interpreted as either UTF-8 or
	       Latin-1, according to whether the "LEX_STUFF_UTF8" flag is set
	       in flags.  The characters are recoded for the lexer buffer,
	       according to how the buffer is currently being interpreted
	       ("lex_bufutf8").	 If a string to be inserted is available as a
	       Perl scalar, the "lex_stuff_sv" function is more convenient.

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

		       void    lex_stuff_pvn(const char *pv, STRLEN len,
					     U32 flags)

       lex_stuff_pvs
	       Like "lex_stuff_pvn", but takes a literal string instead of a
	       string/length pair.

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

		       void    lex_stuff_pvs(const char *pv, U32 flags)

       lex_stuff_sv
	       Insert characters into the lexer buffer ("PL_parser->linestr"),
	       immediately after the current lexing point
	       ("PL_parser->bufptr"), reallocating the buffer if necessary.
	       This means that lexing code that runs later will see the
	       characters as if they had appeared in the input.	 It is not
	       recommended to do this as part of normal parsing, and most uses
	       of this facility run the risk of the inserted characters being
	       interpreted in an unintended manner.

	       The string to be inserted is the string value of sv.  The
	       characters are recoded for the lexer buffer, according to how
	       the buffer is currently being interpreted ("lex_bufutf8").  If
	       a string to be inserted is not already a Perl scalar, the
	       "lex_stuff_pvn" function avoids the need to construct a scalar.

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

		       void    lex_stuff_sv(SV *sv, U32 flags)

       lex_unstuff
	       Discards text about to be lexed, from "PL_parser->bufptr" up to
	       ptr.  Text following ptr will be moved, and the buffer
	       shortened.  This hides the discarded text from any lexing code
	       that runs later, as if the text had never appeared.

	       This is not the normal way to consume lexed text.  For that,
	       use "lex_read_to".

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

		       void    lex_unstuff(char *ptr)

       parse_arithexpr
	       Parse a Perl arithmetic expression.  This may contain operators
	       of precedence down to the bit shift operators.  The expression
	       must be followed (and thus terminated) either by a comparison
	       or lower-precedence operator or by something that would
	       normally terminate an expression such as semicolon.  If flags
	       includes "PARSE_OPTIONAL" then the expression is optional,
	       otherwise it is mandatory.  It is up to the caller to ensure
	       that the dynamic parser state ("PL_parser" et al) is correctly
	       set to reflect the source of the code to be parsed and the
	       lexical context for the expression.

	       The op tree representing the expression is returned.  If an
	       optional expression is absent, a null pointer is returned,
	       otherwise the pointer will be non-null.

	       If an error occurs in parsing or compilation, in most cases a
	       valid op tree is returned anyway.  The error is reflected in
	       the parser state, normally resulting in a single exception at
	       the top level of parsing which covers all the compilation
	       errors that occurred.  Some compilation errors, however, will
	       throw an exception immediately.

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

		       OP *    parse_arithexpr(U32 flags)

       parse_barestmt
	       Parse a single unadorned Perl statement.	 This may be a normal
	       imperative statement or a declaration that has compile-time
	       effect.	It does not include any label or other affixture.  It
	       is up to the caller to ensure that the dynamic parser state
	       ("PL_parser" et al) is correctly set to reflect the source of
	       the code to be parsed and the lexical context for the
	       statement.

	       The op tree representing the statement is returned.  This may
	       be a null pointer if the statement is null, for example if it
	       was actually a subroutine definition (which has compile-time
	       side effects).  If not null, it will be ops directly
	       implementing the statement, suitable to pass to "newSTATEOP".
	       It will not normally include a "nextstate" or equivalent op
	       (except for those embedded in a scope contained entirely within
	       the statement).

	       If an error occurs in parsing or compilation, in most cases a
	       valid op tree (most likely null) is returned anyway.  The error
	       is reflected in the parser state, normally resulting in a
	       single exception at the top level of parsing which covers all
	       the compilation errors that occurred.  Some compilation errors,
	       however, will throw an exception immediately.

	       The flags parameter is reserved for future use, and must always
	       be zero.

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

		       OP *    parse_barestmt(U32 flags)

       parse_block
	       Parse a single complete Perl code block.	 This consists of an
	       opening brace, a sequence of statements, and a closing brace.
	       The block constitutes a lexical scope, so "my" variables and
	       various compile-time effects can be contained within it.	 It is
	       up to the caller to ensure that the dynamic parser state
	       ("PL_parser" et al) is correctly set to reflect the source of
	       the code to be parsed and the lexical context for the
	       statement.

	       The op tree representing the code block is returned.  This is
	       always a real op, never a null pointer.	It will normally be a
	       "lineseq" list, including "nextstate" or equivalent ops.	 No
	       ops to construct any kind of runtime scope are included by
	       virtue of it being a block.

	       If an error occurs in parsing or compilation, in most cases a
	       valid op tree (most likely null) is returned anyway.  The error
	       is reflected in the parser state, normally resulting in a
	       single exception at the top level of parsing which covers all
	       the compilation errors that occurred.  Some compilation errors,
	       however, will throw an exception immediately.

	       The flags parameter is reserved for future use, and must always
	       be zero.

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

		       OP *    parse_block(U32 flags)

       parse_fullexpr
	       Parse a single complete Perl expression.	 This allows the full
	       expression grammar, including the lowest-precedence operators
	       such as "or".  The expression must be followed (and thus
	       terminated) by a token that an expression would normally be
	       terminated by: end-of-file, closing bracketing punctuation,
	       semicolon, or one of the keywords that signals a postfix
	       expression-statement modifier.  If flags includes
	       "PARSE_OPTIONAL" then the expression is optional, otherwise it
	       is mandatory.  It is up to the caller to ensure that the
	       dynamic parser state ("PL_parser" et al) is correctly set to
	       reflect the source of the code to be parsed and the lexical
	       context for the expression.

	       The op tree representing the expression is returned.  If an
	       optional expression is absent, a null pointer is returned,
	       otherwise the pointer will be non-null.

	       If an error occurs in parsing or compilation, in most cases a
	       valid op tree is returned anyway.  The error is reflected in
	       the parser state, normally resulting in a single exception at
	       the top level of parsing which covers all the compilation
	       errors that occurred.  Some compilation errors, however, will
	       throw an exception immediately.

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

		       OP *    parse_fullexpr(U32 flags)

       parse_fullstmt
	       Parse a single complete Perl statement.	This may be a normal
	       imperative statement or a declaration that has compile-time
	       effect, and may include optional labels.	 It is up to the
	       caller to ensure that the dynamic parser state ("PL_parser" et
	       al) is correctly set to reflect the source of the code to be
	       parsed and the lexical context for the statement.

	       The op tree representing the statement is returned.  This may
	       be a null pointer if the statement is null, for example if it
	       was actually a subroutine definition (which has compile-time
	       side effects).  If not null, it will be the result of a
	       "newSTATEOP" call, normally including a "nextstate" or
	       equivalent op.

	       If an error occurs in parsing or compilation, in most cases a
	       valid op tree (most likely null) is returned anyway.  The error
	       is reflected in the parser state, normally resulting in a
	       single exception at the top level of parsing which covers all
	       the compilation errors that occurred.  Some compilation errors,
	       however, will throw an exception immediately.

	       The flags parameter is reserved for future use, and must always
	       be zero.

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

		       OP *    parse_fullstmt(U32 flags)

       parse_label
	       Parse a single label, possibly optional, of the type that may
	       prefix a Perl statement.	 It is up to the caller to ensure that
	       the dynamic parser state ("PL_parser" et al) is correctly set
	       to reflect the source of the code to be parsed.	If flags
	       includes "PARSE_OPTIONAL" then the label is optional, otherwise
	       it is mandatory.

	       The name of the label is returned in the form of a fresh
	       scalar.	If an optional label is absent, a null pointer is
	       returned.

	       If an error occurs in parsing, which can only occur if the
	       label is mandatory, a valid label is returned anyway.  The
	       error is reflected in the parser state, normally resulting in a
	       single exception at the top level of parsing which covers all
	       the compilation errors that occurred.

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

		       SV *    parse_label(U32 flags)

       parse_listexpr
	       Parse a Perl list expression.  This may contain operators of
	       precedence down to the comma operator.  The expression must be
	       followed (and thus terminated) either by a low-precedence logic
	       operator such as "or" or by something that would normally
	       terminate an expression such as semicolon.  If flags includes
	       "PARSE_OPTIONAL" then the expression is optional, otherwise it
	       is mandatory.  It is up to the caller to ensure that the
	       dynamic parser state ("PL_parser" et al) is correctly set to
	       reflect the source of the code to be parsed and the lexical
	       context for the expression.

	       The op tree representing the expression is returned.  If an
	       optional expression is absent, a null pointer is returned,
	       otherwise the pointer will be non-null.

	       If an error occurs in parsing or compilation, in most cases a
	       valid op tree is returned anyway.  The error is reflected in
	       the parser state, normally resulting in a single exception at
	       the top level of parsing which covers all the compilation
	       errors that occurred.  Some compilation errors, however, will
	       throw an exception immediately.

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

		       OP *    parse_listexpr(U32 flags)

       parse_stmtseq
	       Parse a sequence of zero or more Perl statements.  These may be
	       normal imperative statements, including optional labels, or
	       declarations that have compile-time effect, or any mixture
	       thereof.	 The statement sequence ends when a closing brace or
	       end-of-file is encountered in a place where a new statement
	       could have validly started.  It is up to the caller to ensure
	       that the dynamic parser state ("PL_parser" et al) is correctly
	       set to reflect the source of the code to be parsed and the
	       lexical context for the statements.

	       The op tree representing the statement sequence is returned.
	       This may be a null pointer if the statements were all null, for
	       example if there were no statements or if there were only
	       subroutine definitions (which have compile-time side effects).
	       If not null, it will be a "lineseq" list, normally including
	       "nextstate" or equivalent ops.

	       If an error occurs in parsing or compilation, in most cases a
	       valid op tree is returned anyway.  The error is reflected in
	       the parser state, normally resulting in a single exception at
	       the top level of parsing which covers all the compilation
	       errors that occurred.  Some compilation errors, however, will
	       throw an exception immediately.

	       The flags parameter is reserved for future use, and must always
	       be zero.

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

		       OP *    parse_stmtseq(U32 flags)

       parse_termexpr
	       Parse a Perl term expression.  This may contain operators of
	       precedence down to the assignment operators.  The expression
	       must be followed (and thus terminated) either by a comma or
	       lower-precedence operator or by something that would normally
	       terminate an expression such as semicolon.  If flags includes
	       "PARSE_OPTIONAL" then the expression is optional, otherwise it
	       is mandatory.  It is up to the caller to ensure that the
	       dynamic parser state ("PL_parser" et al) is correctly set to
	       reflect the source of the code to be parsed and the lexical
	       context for the expression.

	       The op tree representing the expression is returned.  If an
	       optional expression is absent, a null pointer is returned,
	       otherwise the pointer will be non-null.

	       If an error occurs in parsing or compilation, in most cases a
	       valid op tree is returned anyway.  The error is reflected in
	       the parser state, normally resulting in a single exception at
	       the top level of parsing which covers all the compilation
	       errors that occurred.  Some compilation errors, however, will
	       throw an exception immediately.

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

		       OP *    parse_termexpr(U32 flags)

       PL_parser
	       Pointer to a structure encapsulating the state of the parsing
	       operation currently in progress.	 The pointer can be locally
	       changed to perform a nested parse without interfering with the
	       state of an outer parse.	 Individual members of "PL_parser"
	       have their own documentation.

       PL_parser->bufend
	       Direct pointer to the end of the chunk of text currently being
	       lexed, the end of the lexer buffer.  This is equal to
	       "SvPVX(PL_parser->linestr) + SvCUR(PL_parser->linestr)".	 A NUL
	       character (zero octet) is always located at the end of the
	       buffer, and does not count as part of the buffer's contents.

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

       PL_parser->bufptr
	       Points to the current position of lexing inside the lexer
	       buffer.	Characters around this point may be freely examined,
	       within the range delimited by "SvPVX("PL_parser->linestr")" and
	       "PL_parser->bufend".  The octets of the buffer may be intended
	       to be interpreted as either UTF-8 or Latin-1, as indicated by
	       "lex_bufutf8".

	       Lexing code (whether in the Perl core or not) moves this
	       pointer past the characters that it consumes.  It is also
	       expected to perform some bookkeeping whenever a newline
	       character is consumed.  This movement can be more conveniently
	       performed by the function "lex_read_to", which handles newlines
	       appropriately.

	       Interpretation of the buffer's octets can be abstracted out by
	       using the slightly higher-level functions "lex_peek_unichar"
	       and "lex_read_unichar".

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

       PL_parser->linestart
	       Points to the start of the current line inside the lexer
	       buffer.	This is useful for indicating at which column an error
	       occurred, and not much else.  This must be updated by any
	       lexing code that consumes a newline; the function "lex_read_to"
	       handles this detail.

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

       PL_parser->linestr
	       Buffer scalar containing the chunk currently under
	       consideration of the text currently being lexed.	 This is
	       always a plain string scalar (for which "SvPOK" is true).  It
	       is not intended to be used as a scalar by normal scalar means;
	       instead refer to the buffer directly by the pointer variables
	       described below.

	       The lexer maintains various "char*" pointers to things in the
	       "PL_parser->linestr" buffer.  If "PL_parser->linestr" is ever
	       reallocated, all of these pointers must be updated.  Don't
	       attempt to do this manually, but rather use "lex_grow_linestr"
	       if you need to reallocate the buffer.

	       The content of the text chunk in the buffer is commonly exactly
	       one complete line of input, up to and including a newline
	       terminator, but there are situations where it is otherwise.
	       The octets of the buffer may be intended to be interpreted as
	       either UTF-8 or Latin-1.	 The function "lex_bufutf8" tells you
	       which.  Do not use the "SvUTF8" flag on this scalar, which may
	       disagree with it.

	       For direct examination of the buffer, the variable
	       "PL_parser->bufend" points to the end of the buffer.  The
	       current lexing position is pointed to by "PL_parser->bufptr".
	       Direct use of these pointers is usually preferable to
	       examination of the scalar through normal scalar means.

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

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(const SV* sv, int type)

       mg_findext
	       Finds the magic pointer of "type" with the given "vtbl" for the
	       "SV".  See "sv_magicext".

		       MAGIC*  mg_findext(const SV* sv, int type,
					  const MGVTBL *vtbl)

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

		       int     mg_free(SV* sv)

       mg_free_type
	       Remove any magic of type how from the SV sv.  See "sv_magic".

		       void    mg_free_type(SV *sv, int how)

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

		       int     mg_get(SV* sv)

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

		       U32     mg_length(SV* sv)

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

		       void    mg_magical(SV* sv)

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

		       int     mg_set(SV* sv)

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

		       void    SvGETMAGIC(SV* sv)

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

		       void    SvLOCK(SV* sv)

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

		       void    SvSETMAGIC(SV* sv)

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

		       void    SvSetMagicSV(SV* dsb, SV* ssv)

       SvSetMagicSV_nosteal
	       Like "SvSetSV_nosteal", but does any set magic required
	       afterwards.

		       void    SvSetMagicSV_nosteal(SV* dsv, SV* ssv)

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

		       void    SvSetSV(SV* dsb, SV* ssv)

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

		       void    SvSetSV_nosteal(SV* dsv, SV* ssv)

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

		       void    SvSHARE(SV* sv)

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

		       void    SvUNLOCK(SV* sv)

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

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

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

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

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

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

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

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

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

	       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
	       perlhacktips).  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)

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

		       char*   savesharedpvs(const char* s)

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

		       char*   savesharedsvpv(SV *sv)

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

		       char*   savesvpv(SV* sv)

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

		       void    StructCopy(type src, type dest, type)

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

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

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

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

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

		       void    fbm_compile(SV* sv, U32 flags)

       fbm_instr
	       Returns the location of the SV in the string delimited by "str"
	       and "strend".  It returns "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* littlestr,
					 U32 flags)

       foldEQ  Returns true if the leading len bytes of the strings s1 and s2
	       are the same case-insensitively; false otherwise.  Uppercase
	       and lowercase ASCII range bytes match themselves and their
	       opposite case counterparts.  Non-cased and non-ASCII range
	       bytes match only themselves.

		       I32     foldEQ(const char* a, const char* b, I32 len)

       foldEQ_locale
	       Returns true if the leading len bytes of the strings s1 and s2
	       are the same case-insensitively in the current locale; false
	       otherwise.

		       I32     foldEQ_locale(const char* a, const char* b,
					     I32 len)

       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)

       mess    Take a sprintf-style format pattern and argument list.  These
	       are used to generate a string message.  If the message does not
	       end with a newline, then it will be extended with some
	       indication of the current location in the code, as described
	       for "mess_sv".

	       Normally, the resulting message is returned in a new mortal SV.
	       During global destruction a single SV may be shared between
	       uses of this function.

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

       mess_sv Expands a message, intended for the user, to include an
	       indication of the current location in the code, if the message
	       does not already appear to be complete.

	       "basemsg" is the initial message or object.  If it is a
	       reference, it will be used as-is and will be the result of this
	       function.  Otherwise it is used as a string, and if it already
	       ends with a newline, it is taken to be complete, and the result
	       of this function will be the same string.  If the message does
	       not end with a newline, then a segment such as "at foo.pl line
	       37" will be appended, and possibly other clauses indicating the
	       current state of execution.  The resulting message will end
	       with a dot and a newline.

	       Normally, the resulting message is returned in a new mortal SV.
	       During global destruction a single SV may be shared between
	       uses of this function.  If "consume" is true, then the function
	       is permitted (but not required) to modify and return "basemsg"
	       instead of allocating a new SV.

		       SV *    mess_sv(SV *basemsg, bool consume)

       my_snprintf
	       The C library "snprintf" functionality, if available and
	       standards-compliant (uses "vsnprintf", actually).  However, 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_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)

       new_version
	       Returns a new version object based on the passed in SV:

		   SV *sv = new_version(SV *ver);

	       Does not alter the passed in ver SV.  See "upg_version" if you
	       want to upgrade the SV.

		       SV*     new_version(SV *ver)

       prescan_version
	       Validate that a given string can be parsed as a version object,
	       but doesn't actually perform the parsing.  Can use either
	       strict or lax validation rules.	Can optionally set a number of
	       hint variables to save the parsing code some time when
	       tokenizing.

		       const char* prescan_version(const char *s, bool strict,
						   const char** errstr,
						   bool *sqv,
						   int *ssaw_decimal,
						   int *swidth, bool *salpha)

       scan_version
	       Returns a pointer to the next character after the parsed
	       version string, as well as upgrading the passed in SV to an RV.

	       Function must be called with an already existing SV like

		   sv = newSV(0);
		   s = scan_version(s, SV *sv, bool qv);

	       Performs some preprocessing to the string to ensure that it has
	       the correct characteristics of a version.  Flags the object if
	       it contains an underscore (which denotes this is an alpha
	       version).  The boolean qv denotes that the version should be
	       interpreted as if it had multiple decimals, even if it doesn't.

		       const char* scan_version(const char *s, SV *rv, bool qv)

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

		       bool    strEQ(char* s1, char* s2)

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

		       bool    strGE(char* s1, char* s2)

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

		       bool    strGT(char* s1, char* s2)

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

		       bool    strLE(char* s1, char* s2)

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

		       bool    strLT(char* s1, char* s2)

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

		       bool    strNE(char* s1, char* s2)

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

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

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

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

       sv_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)

       upg_version
	       In-place upgrade of the supplied SV to a version object.

		   SV *sv = upg_version(SV *sv, bool qv);

	       Returns a pointer to the upgraded SV.  Set the boolean qv if
	       you want to force this SV to be interpreted as an "extended"
	       version.

		       SV*     upg_version(SV *ver, bool qv)

       vcmp    Version object aware cmp.  Both operands must already have been
	       converted into version objects.

		       int     vcmp(SV *lhv, SV *rhv)

       vmess   "pat" and "args" are a sprintf-style format pattern and
	       encapsulated argument list.  These are used to generate a
	       string message.	If the message does not end with a newline,
	       then it will be extended with some indication of the current
	       location in the code, as described for "mess_sv".

	       Normally, the resulting message is returned in a new mortal SV.
	       During global destruction a single SV may be shared between
	       uses of this function.

		       SV *    vmess(const char *pat, va_list *args)

       vnormal Accepts a version object and returns the normalized string
	       representation.	Call like:

		   sv = vnormal(rv);

	       NOTE: you can pass either the object directly or the SV
	       contained within the RV.

	       The SV returned has a refcount of 1.

		       SV*     vnormal(SV *vs)

       vnumify Accepts a version object and returns the normalized floating
	       point representation.  Call like:

		   sv = vnumify(rv);

	       NOTE: you can pass either the object directly or the SV
	       contained within the RV.

	       The SV returned has a refcount of 1.

		       SV*     vnumify(SV *vs)

       vstringify
	       In order to maintain maximum compatibility with earlier
	       versions of Perl, this function will return either the floating
	       point notation or the multiple dotted notation, depending on
	       whether the original version contained 1 or more dots,
	       respectively.

	       The SV returned has a refcount of 1.

		       SV*     vstringify(SV *vs)

       vverify Validates that the SV contains valid internal structure for a
	       version object.	It may be passed either the version object
	       (RV) or the hash itself (HV).  If the structure is valid, it
	       returns the HV.	If the structure is invalid, it returns NULL.

		   SV *hv = vverify(sv);

	       Note that it only confirms the bare minimum structure (so as
	       not to get confused by derived classes which may contain
	       additional hash entries):

		       SV*     vverify(SV *vs)

MRO Functions
       mro_get_linear_isa
	       Returns the mro linearisation for the given stash.  By default,
	       this will be whatever "mro_get_linear_isa_dfs" returns unless
	       some other MRO is in effect for the stash.  The return value is
	       a read-only AV*.

	       You are responsible for "SvREFCNT_inc()" on the return value if
	       you plan to store it anywhere semi-permanently (otherwise it
	       might be deleted out from under you the next time the cache is
	       invalidated).

		       AV*     mro_get_linear_isa(HV* stash)

       mro_method_changed_in
	       Invalidates method caching on any child classes of the given
	       stash, so that they might notice the changes in this one.

	       Ideally, all instances of "PL_sub_generation++" in perl source
	       outside of mro.c should be replaced by calls to this.

	       Perl automatically handles most of the common ways a method
	       might be redefined.  However, there are a few ways you could
	       change a method in a stash without the cache code noticing, in
	       which case you need to call this method afterwards:

	       1) Directly manipulating the stash HV entries from XS code.

	       2) Assigning a reference to a readonly scalar constant into a
	       stash entry in order to create a constant subroutine (like
	       constant.pm does).

	       This same method is available from pure perl via,
	       "mro::method_changed_in(classname)".

		       void    mro_method_changed_in(HV* stash)

       mro_register
	       Registers a custom mro plugin.  See perlmroapi for details.

		       void    mro_register(const struct mro_alg *mro)

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 perlcall.

			       POP_MULTICALL;

       PUSH_MULTICALL
	       Opening bracket for a lightweight callback.  See "LIGHTWEIGHT
	       CALLBACKS" in perlcall.

			       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_UNDERSCORES" is set in *flags then the
	       binary number may use '_' characters to separate digits.

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

       grok_hex
	       converts a string representing a hex number to numeric form.

	       On entry start and *len give the string to scan, *flags gives
	       conversion flags, and result should be NULL or a pointer to an
	       NV.  The scan stops at the end of the string, or the first
	       invalid character.  Unless "PERL_SCAN_SILENT_ILLDIGIT" is set
	       in *flags, encountering an invalid character will also trigger
	       a warning.  On return *len is set to the length of the scanned
	       string, and *flags gives output flags.

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

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

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

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

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

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

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

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

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

       grok_oct
	       converts a string representing an octal number to numeric form.

	       On entry start and *len give the string to scan, *flags gives
	       conversion flags, and result should be NULL or a pointer to an
	       NV.  The scan stops at the end of the string, or the first
	       invalid character.  Unless "PERL_SCAN_SILENT_ILLDIGIT" is set
	       in *flags, encountering an 8 or 9 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(const 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 implementation.  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 'signbit' 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(const char* start, STRLEN len,
					STRLEN* retlen)

       scan_hex
	       For backwards compatibility. Use "grok_hex" instead.

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

       scan_oct
	       For backwards compatibility. Use "grok_oct" instead.

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

Optree construction
       newASSIGNOP
	       Constructs, checks, and returns an assignment op.  left and
	       right supply the parameters of the assignment; they are
	       consumed by this function and become part of the constructed op
	       tree.

	       If optype is "OP_ANDASSIGN", "OP_ORASSIGN", or "OP_DORASSIGN",
	       then a suitable conditional optree is constructed.  If optype
	       is the opcode of a binary operator, such as "OP_BIT_OR", then
	       an op is constructed that performs the binary operation and
	       assigns the result to the left argument.	 Either way, if optype
	       is non-zero then flags has no effect.

	       If optype is zero, then a plain scalar or list assignment is
	       constructed.  Which type of assignment it is is automatically
	       determined.  flags gives the eight bits of "op_flags", except
	       that "OPf_KIDS" will be set automatically, and, shifted up
	       eight bits, the eight bits of "op_private", except that the bit
	       with value 1 or 2 is automatically set as required.

		       OP *    newASSIGNOP(I32 flags, OP *left, I32 optype,
					   OP *right)

       newBINOP
	       Constructs, checks, and returns an op of any binary type.  type
	       is the opcode.  flags gives the eight bits of "op_flags",
	       except that "OPf_KIDS" will be set automatically, and, shifted
	       up eight bits, the eight bits of "op_private", except that the
	       bit with value 1 or 2 is automatically set as required.	first
	       and last supply up to two ops to be the direct children of the
	       binary op; they are consumed by this function and become part
	       of the constructed op tree.

		       OP *    newBINOP(I32 type, I32 flags, OP *first,
					OP *last)

       newCONDOP
	       Constructs, checks, and returns a conditional-expression
	       ("cond_expr") op.  flags gives the eight bits of "op_flags",
	       except that "OPf_KIDS" will be set automatically, and, shifted
	       up eight bits, the eight bits of "op_private", except that the
	       bit with value 1 is automatically set.  first supplies the
	       expression selecting between the two branches, and trueop and
	       falseop supply the branches; they are consumed by this function
	       and become part of the constructed op tree.

		       OP *    newCONDOP(I32 flags, OP *first, OP *trueop,
					 OP *falseop)

       newFOROP
	       Constructs, checks, and returns an op tree expressing a
	       "foreach" loop (iteration through a list of values).  This is a
	       heavyweight loop, with structure that allows exiting the loop
	       by "last" and suchlike.

	       sv optionally supplies the variable that will be aliased to
	       each item in turn; if null, it defaults to $_ (either lexical
	       or global).  expr supplies the list of values to iterate over.
	       block supplies the main body of the loop, and cont optionally
	       supplies a "continue" block that operates as a second half of
	       the body.  All of these optree inputs are consumed by this
	       function and become part of the constructed op tree.

	       flags gives the eight bits of "op_flags" for the "leaveloop" op
	       and, shifted up eight bits, the eight bits of "op_private" for
	       the "leaveloop" op, except that (in both cases) some bits will
	       be set automatically.

		       OP *    newFOROP(I32 flags, OP *sv, OP *expr, OP *block,
					OP *cont)

       newGIVENOP
	       Constructs, checks, and returns an op tree expressing a "given"
	       block.  cond supplies the expression that will be locally
	       assigned to a lexical variable, and block supplies the body of
	       the "given" construct; they are consumed by this function and
	       become part of the constructed op tree.	defsv_off is the pad
	       offset of the scalar lexical variable that will be affected.

		       OP *    newGIVENOP(OP *cond, OP *block,
					  PADOFFSET defsv_off)

       newGVOP Constructs, checks, and returns an op of any type that involves
	       an embedded reference to a GV.  type is the opcode.  flags
	       gives the eight bits of "op_flags".  gv identifies the GV that
	       the op should reference; calling this function does not
	       transfer ownership of any reference to it.

		       OP *    newGVOP(I32 type, I32 flags, GV *gv)

       newLISTOP
	       Constructs, checks, and returns an op of any list type.	type
	       is the opcode.  flags gives the eight bits of "op_flags",
	       except that "OPf_KIDS" will be set automatically if required.
	       first and last supply up to two ops to be direct children of
	       the list op; they are consumed by this function and become part
	       of the constructed op tree.

		       OP *    newLISTOP(I32 type, I32 flags, OP *first,
					 OP *last)

       newLOGOP
	       Constructs, checks, and returns a logical (flow control) op.
	       type is the opcode.  flags gives the eight bits of "op_flags",
	       except that "OPf_KIDS" will be set automatically, and, shifted
	       up eight bits, the eight bits of "op_private", except that the
	       bit with value 1 is automatically set.  first supplies the
	       expression controlling the flow, and other supplies the side
	       (alternate) chain of ops; they are consumed by this function
	       and become part of the constructed op tree.

		       OP *    newLOGOP(I32 type, I32 flags, OP *first,
					OP *other)

       newLOOPEX
	       Constructs, checks, and returns a loop-exiting op (such as
	       "goto" or "last").  type is the opcode.	label supplies the
	       parameter determining the target of the op; it is consumed by
	       this function and become part of the constructed op tree.

		       OP *    newLOOPEX(I32 type, OP *label)

       newLOOPOP
	       Constructs, checks, and returns an op tree expressing a loop.
	       This is only a loop in the control flow through the op tree; it
	       does not have the heavyweight loop structure that allows
	       exiting the loop by "last" and suchlike.	 flags gives the eight
	       bits of "op_flags" for the top-level op, except that some bits
	       will be set automatically as required.  expr supplies the
	       expression controlling loop iteration, and block supplies the
	       body of the loop; they are consumed by this function and become
	       part of the constructed op tree.	 debuggable is currently
	       unused and should always be 1.

		       OP *    newLOOPOP(I32 flags, I32 debuggable, OP *expr,
					 OP *block)

       newNULLLIST
	       Constructs, checks, and returns a new "stub" op, which
	       represents an empty list expression.

		       OP *    newNULLLIST()

       newOP   Constructs, checks, and returns an op of any base type (any
	       type that has no extra fields).	type is the opcode.  flags
	       gives the eight bits of "op_flags", and, shifted up eight bits,
	       the eight bits of "op_private".

		       OP *    newOP(I32 type, I32 flags)

       newPADOP
	       Constructs, checks, and returns an op of any type that involves
	       a reference to a pad element.  type is the opcode.  flags gives
	       the eight bits of "op_flags".  A pad slot is automatically
	       allocated, and is populated with sv; this function takes
	       ownership of one reference to it.

	       This function only exists if Perl has been compiled to use
	       ithreads.

		       OP *    newPADOP(I32 type, I32 flags, SV *sv)

       newPMOP Constructs, checks, and returns an op of any pattern matching
	       type.  type is the opcode.  flags gives the eight bits of
	       "op_flags" and, shifted up eight bits, the eight bits of
	       "op_private".

		       OP *    newPMOP(I32 type, I32 flags)

       newPVOP Constructs, checks, and returns an op of any type that involves
	       an embedded C-level pointer (PV).  type is the opcode.  flags
	       gives the eight bits of "op_flags".  pv supplies the C-level
	       pointer, which must have been allocated using
	       "PerlMemShared_malloc"; the memory will be freed when the op is
	       destroyed.

		       OP *    newPVOP(I32 type, I32 flags, char *pv)

       newRANGE
	       Constructs and returns a "range" op, with subordinate "flip"
	       and "flop" ops.	flags gives the eight bits of "op_flags" for
	       the "flip" op and, shifted up eight bits, the eight bits of
	       "op_private" for both the "flip" and "range" ops, except that
	       the bit with value 1 is automatically set.  left and right
	       supply the expressions controlling the endpoints of the range;
	       they are consumed by this function and become part of the
	       constructed op tree.

		       OP *    newRANGE(I32 flags, OP *left, OP *right)

       newSLICEOP
	       Constructs, checks, and returns an "lslice" (list slice) op.
	       flags gives the eight bits of "op_flags", except that
	       "OPf_KIDS" will be set automatically, and, shifted up eight
	       bits, the eight bits of "op_private", except that the bit with
	       value 1 or 2 is automatically set as required.  listval and
	       subscript supply the parameters of the slice; they are consumed
	       by this function and become part of the constructed op tree.

		       OP *    newSLICEOP(I32 flags, OP *subscript,
					  OP *listval)

       newSTATEOP
	       Constructs a state op (COP).  The state op is normally a
	       "nextstate" op, but will be a "dbstate" op if debugging is
	       enabled for currently-compiled code.  The state op is populated
	       from "PL_curcop" (or "PL_compiling").  If label is non-null, it
	       supplies the name of a label to attach to the state op; this
	       function takes ownership of the memory pointed at by label, and
	       will free it.  flags gives the eight bits of "op_flags" for the
	       state op.

	       If o is null, the state op is returned.	Otherwise the state op
	       is combined with o into a "lineseq" list op, which is returned.
	       o is consumed by this function and becomes part of the returned
	       op tree.

		       OP *    newSTATEOP(I32 flags, char *label, OP *o)

       newSVOP Constructs, checks, and returns an op of any type that involves
	       an embedded SV.	type is the opcode.  flags gives the eight
	       bits of "op_flags".  sv gives the SV to embed in the op; this
	       function takes ownership of one reference to it.

		       OP *    newSVOP(I32 type, I32 flags, SV *sv)

       newUNOP Constructs, checks, and returns an op of any unary type.	 type
	       is the opcode.  flags gives the eight bits of "op_flags",
	       except that "OPf_KIDS" will be set automatically if required,
	       and, shifted up eight bits, the eight bits of "op_private",
	       except that the bit with value 1 is automatically set.  first
	       supplies an optional op to be the direct child of the unary op;
	       it is consumed by this function and become part of the
	       constructed op tree.

		       OP *    newUNOP(I32 type, I32 flags, OP *first)

       newWHENOP
	       Constructs, checks, and returns an op tree expressing a "when"
	       block.  cond supplies the test expression, and block supplies
	       the block that will be executed if the test evaluates to true;
	       they are consumed by this function and become part of the
	       constructed op tree.  cond will be interpreted DWIMically,
	       often as a comparison against $_, and may be null to generate a
	       "default" block.

		       OP *    newWHENOP(OP *cond, OP *block)

       newWHILEOP
	       Constructs, checks, and returns an op tree expressing a "while"
	       loop.  This is a heavyweight loop, with structure that allows
	       exiting the loop by "last" and suchlike.

	       loop is an optional preconstructed "enterloop" op to use in the
	       loop; if it is null then a suitable op will be constructed
	       automatically.  expr supplies the loop's controlling
	       expression.  block supplies the main body of the loop, and cont
	       optionally supplies a "continue" block that operates as a
	       second half of the body.	 All of these optree inputs are
	       consumed by this function and become part of the constructed op
	       tree.

	       flags gives the eight bits of "op_flags" for the "leaveloop" op
	       and, shifted up eight bits, the eight bits of "op_private" for
	       the "leaveloop" op, except that (in both cases) some bits will
	       be set automatically.  debuggable is currently unused and
	       should always be 1.  has_my can be supplied as true to force
	       the loop body to be enclosed in its own scope.

		       OP *    newWHILEOP(I32 flags, I32 debuggable,
					  LOOP *loop, OP *expr, OP *block,
					  OP *cont, I32 has_my)

Optree Manipulation Functions
       ck_entersub_args_list
	       Performs the default fixup of the arguments part of an
	       "entersub" op tree.  This consists of applying list context to
	       each of the argument ops.  This is the standard treatment used
	       on a call marked with "&", or a method call, or a call through
	       a subroutine reference, or any other call where the callee
	       can't be identified at compile time, or a call where the callee
	       has no prototype.

		       OP *    ck_entersub_args_list(OP *entersubop)

       ck_entersub_args_proto
	       Performs the fixup of the arguments part of an "entersub" op
	       tree based on a subroutine prototype.  This makes various
	       modifications to the argument ops, from applying context up to
	       inserting "refgen" ops, and checking the number and syntactic
	       types of arguments, as directed by the prototype.  This is the
	       standard treatment used on a subroutine call, not marked with
	       "&", where the callee can be identified at compile time and has
	       a prototype.

	       protosv supplies the subroutine prototype to be applied to the
	       call.  It may be a normal defined scalar, of which the string
	       value will be used.  Alternatively, for convenience, it may be
	       a subroutine object (a "CV*" that has been cast to "SV*") which
	       has a prototype.	 The prototype supplied, in whichever form,
	       does not need to match the actual callee referenced by the op
	       tree.

	       If the argument ops disagree with the prototype, for example by
	       having an unacceptable number of arguments, a valid op tree is
	       returned anyway.	 The error is reflected in the parser state,
	       normally resulting in a single exception at the top level of
	       parsing which covers all the compilation errors that occurred.
	       In the error message, the callee is referred to by the name
	       defined by the namegv parameter.

		       OP *    ck_entersub_args_proto(OP *entersubop,
						      GV *namegv, SV *protosv)

       ck_entersub_args_proto_or_list
	       Performs the fixup of the arguments part of an "entersub" op
	       tree either based on a subroutine prototype or using default
	       list-context processing.	 This is the standard treatment used
	       on a subroutine call, not marked with "&", where the callee can
	       be identified at compile time.

	       protosv supplies the subroutine prototype to be applied to the
	       call, or indicates that there is no prototype.  It may be a
	       normal scalar, in which case if it is defined then the string
	       value will be used as a prototype, and if it is undefined then
	       there is no prototype.  Alternatively, for convenience, it may
	       be a subroutine object (a "CV*" that has been cast to "SV*"),
	       of which the prototype will be used if it has one.  The
	       prototype (or lack thereof) supplied, in whichever form, does
	       not need to match the actual callee referenced by the op tree.

	       If the argument ops disagree with the prototype, for example by
	       having an unacceptable number of arguments, a valid op tree is
	       returned anyway.	 The error is reflected in the parser state,
	       normally resulting in a single exception at the top level of
	       parsing which covers all the compilation errors that occurred.
	       In the error message, the callee is referred to by the name
	       defined by the namegv parameter.

		       OP *    ck_entersub_args_proto_or_list(OP *entersubop,
							      GV *namegv,
							      SV *protosv)

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

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

		       SV*     cv_const_sv(const CV *const cv)

       cv_get_call_checker
	       Retrieves the function that will be used to fix up a call to
	       cv.  Specifically, the function is applied to an "entersub" op
	       tree for a subroutine call, not marked with "&", where the
	       callee can be identified at compile time as cv.

	       The C-level function pointer is returned in *ckfun_p, and an SV
	       argument for it is returned in *ckobj_p.	 The function is
	       intended to be called in this manner:

		   entersubop = (*ckfun_p)(aTHX_ entersubop, namegv, (*ckobj_p));

	       In this call, entersubop is a pointer to the "entersub" op,
	       which may be replaced by the check function, and namegv is a GV
	       supplying the name that should be used by the check function to
	       refer to the callee of the "entersub" op if it needs to emit
	       any diagnostics.	 It is permitted to apply the check function
	       in non-standard situations, such as to a call to a different
	       subroutine or to a method call.

	       By default, the function is
	       Perl_ck_entersub_args_proto_or_list, and the SV parameter is cv
	       itself.	This implements standard prototype processing.	It can
	       be changed, for a particular subroutine, by
	       "cv_set_call_checker".

		       void    cv_get_call_checker(CV *cv,
						   Perl_call_checker *ckfun_p,
						   SV **ckobj_p)

       cv_set_call_checker
	       Sets the function that will be used to fix up a call to cv.
	       Specifically, the function is applied to an "entersub" op tree
	       for a subroutine call, not marked with "&", where the callee
	       can be identified at compile time as cv.

	       The C-level function pointer is supplied in ckfun, and an SV
	       argument for it is supplied in ckobj.  The function is intended
	       to be called in this manner:

		   entersubop = ckfun(aTHX_ entersubop, namegv, ckobj);

	       In this call, entersubop is a pointer to the "entersub" op,
	       which may be replaced by the check function, and namegv is a GV
	       supplying the name that should be used by the check function to
	       refer to the callee of the "entersub" op if it needs to emit
	       any diagnostics.	 It is permitted to apply the check function
	       in non-standard situations, such as to a call to a different
	       subroutine or to a method call.

	       The current setting for a particular CV can be retrieved by
	       "cv_get_call_checker".

		       void    cv_set_call_checker(CV *cv,
						   Perl_call_checker ckfun,
						   SV *ckobj)

       LINKLIST
	       Given the root of an optree, link the tree in execution order
	       using the "op_next" pointers and return the first op executed.
	       If this has already been done, it will not be redone, and
	       "o->op_next" will be returned. If "o->op_next" is not already
	       set, o should be at least an "UNOP".

		       OP*     LINKLIST(OP *o)

       newCONSTSUB
	       See "newCONSTSUB_flags".

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

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

	       Currently, the only useful value for "flags" is SVf_UTF8.

	       Passing NULL for SV creates a constant sub equivalent to "sub
	       BAR () {}", which won't be called if used as a destructor, but
	       will suppress the overhead of a call to "AUTOLOAD".  (This
	       form, however, isn't eligible for inlining at compile time.)

		       CV*     newCONSTSUB_flags(HV* stash, const char* name,
						 STRLEN len, U32 flags, SV* sv)

       newXS   Used by "xsubpp" to hook up XSUBs as Perl subs.	filename needs
	       to be static storage, as it is used directly as CvFILE(),
	       without a copy being made.

       op_append_elem
	       Append an item to the list of ops contained directly within a
	       list-type op, returning the lengthened list.  first is the
	       list-type op, and last is the op to append to the list.	optype
	       specifies the intended opcode for the list.  If first is not
	       already a list of the right type, it will be upgraded into one.
	       If either first or last is null, the other is returned
	       unchanged.

		       OP *    op_append_elem(I32 optype, OP *first, OP *last)

       op_append_list
	       Concatenate the lists of ops contained directly within two
	       list-type ops, returning the combined list.  first and last are
	       the list-type ops to concatenate.  optype specifies the
	       intended opcode for the list.  If either first or last is not
	       already a list of the right type, it will be upgraded into one.
	       If either first or last is null, the other is returned
	       unchanged.

		       OP *    op_append_list(I32 optype, OP *first, OP *last)

       OP_CLASS
	       Return the class of the provided OP: that is, which of the *OP
	       structures it uses. For core ops this currently gets the
	       information out of PL_opargs, which does not always accurately
	       reflect the type used.  For custom ops the type is returned
	       from the registration, and it is up to the registree to ensure
	       it is accurate. The value returned will be one of the OA_*
	       constants from op.h.

		       U32     OP_CLASS(OP *o)

       OP_DESC Return a short description of the provided OP.

		       const char * OP_DESC(OP *o)

       op_linklist
	       This function is the implementation of the "LINKLIST" macro. It
	       should not be called directly.

		       OP*     op_linklist(OP *o)

       op_lvalue
	       Propagate lvalue ("modifiable") context to an op and its
	       children.  type represents the context type, roughly based on
	       the type of op that would do the modifying, although "local()"
	       is represented by OP_NULL, because it has no op type of its own
	       (it is signalled by a flag on the lvalue op).

	       This function detects things that can't be modified, such as
	       "$x+1", and generates errors for them. For example, "$x+1 = 2"
	       would cause it to be called with an op of type OP_ADD and a
	       "type" argument of OP_SASSIGN.

	       It also flags things that need to behave specially in an lvalue
	       context, such as "$$x = 5" which might have to vivify a
	       reference in $x.

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

		       OP *    op_lvalue(OP *o, I32 type)

       OP_NAME Return the name of the provided OP. For core ops this looks up
	       the name from the op_type; for custom ops from the op_ppaddr.

		       const char * OP_NAME(OP *o)

       op_prepend_elem
	       Prepend an item to the list of ops contained directly within a
	       list-type op, returning the lengthened list.  first is the op
	       to prepend to the list, and last is the list-type op.  optype
	       specifies the intended opcode for the list.  If last is not
	       already a list of the right type, it will be upgraded into one.
	       If either first or last is null, the other is returned
	       unchanged.

		       OP *    op_prepend_elem(I32 optype, OP *first, OP *last)

       op_scope
	       Wraps up an op tree with some additional ops so that at runtime
	       a dynamic scope will be created.	 The original ops run in the
	       new dynamic scope, and then, provided that they exit normally,
	       the scope will be unwound.  The additional ops used to create
	       and unwind the dynamic scope will normally be an
	       "enter"/"leave" pair, but a "scope" op may be used instead if
	       the ops are simple enough to not need the full dynamic scope
	       structure.

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

		       OP *    op_scope(OP *o)

       rv2cv_op_cv
	       Examines an op, which is expected to identify a subroutine at
	       runtime, and attempts to determine at compile time which
	       subroutine it identifies.  This is normally used during Perl
	       compilation to determine whether a prototype can be applied to
	       a function call.	 cvop is the op being considered, normally an
	       "rv2cv" op.  A pointer to the identified subroutine is
	       returned, if it could be determined statically, and a null
	       pointer is returned if it was not possible to determine
	       statically.

	       Currently, the subroutine can be identified statically if the
	       RV that the "rv2cv" is to operate on is provided by a suitable
	       "gv" or "const" op.  A "gv" op is suitable if the GV's CV slot
	       is populated.  A "const" op is suitable if the constant value
	       must be an RV pointing to a CV.	Details of this process may
	       change in future versions of Perl.  If the "rv2cv" op has the
	       "OPpENTERSUB_AMPER" flag set then no attempt is made to
	       identify the subroutine statically: this flag is used to
	       suppress compile-time magic on a subroutine call, forcing it to
	       use default runtime behaviour.

	       If flags has the bit "RV2CVOPCV_MARK_EARLY" set, then the
	       handling of a GV reference is modified.	If a GV was examined
	       and its CV slot was found to be empty, then the "gv" op has the
	       "OPpEARLY_CV" flag set.	If the op is not optimised away, and
	       the CV slot is later populated with a subroutine having a
	       prototype, that flag eventually triggers the warning "called
	       too early to check prototype".

	       If flags has the bit "RV2CVOPCV_RETURN_NAME_GV" set, then
	       instead of returning a pointer to the subroutine it returns a
	       pointer to the GV giving the most appropriate name for the
	       subroutine in this context.  Normally this is just the "CvGV"
	       of the subroutine, but for an anonymous ("CvANON") subroutine
	       that is referenced through a GV it will be the referencing GV.
	       The resulting "GV*" is cast to "CV*" to be returned.  A null
	       pointer is returned as usual if there is no statically-
	       determinable subroutine.

		       CV *    rv2cv_op_cv(OP *cvop, U32 flags)

Pad Data Structures
       CvPADLIST
	       CV's can have CvPADLIST(cv) set to point to an AV.  This is the
	       CV's scratchpad, which stores lexical variables and opcode
	       temporary and per-thread values.

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

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

	       The CvPADLIST AV has the REFCNT of its component items managed
	       "manually" (mostly in pad.c) rather than by normal av.c rules.
	       So we turn off AvREAL just before freeing it, to let av.c know
	       not to touch the entries.  The items in the AV are not SVs as
	       for a normal AV, but other AVs:

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

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

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

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

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

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

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

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

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

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

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

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

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

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

		       PADLIST * CvPADLIST(CV *cv)

       pad_add_name_pvs
	       Exactly like "pad_add_name_pvn", but takes a literal string
	       instead of a string/length pair.

		       PADOFFSET pad_add_name_pvs(const char *name, U32 flags,
						  HV *typestash, HV *ourstash)

       pad_findmy_pvs
	       Exactly like "pad_findmy_pvn", but takes a literal string
	       instead of a string/length pair.

		       PADOFFSET pad_findmy_pvs(const char *name, U32 flags)

       pad_new Create a new padlist, updating the global variables for the
	       currently-compiling padlist to point to the new padlist.	 The
	       following flags can be OR'ed together:

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

		       PADLIST * pad_new(int flags)

       PL_comppad
	       During compilation, this points to the array containing the
	       values part of the pad for the currently-compiling code.	 (At
	       runtime a CV may have many such value arrays; at compile time
	       just one is constructed.)  At runtime, this points to the array
	       containing the currently-relevant values for the pad for the
	       currently-executing code.

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

       PL_comppad_name
	       During compilation, this points to the array containing the
	       names part of the pad for the currently-compiling code.

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

       PL_curpad
	       Points directly to the body of the "PL_comppad" array.  (I.e.,
	       this is "AvARRAY(PL_comppad)".)

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

Per-Interpreter 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_opfreehook
	       When non-"NULL", the function pointed by this variable will be
	       called each time an OP is freed with the corresponding OP as
	       the argument.  This allows extensions to free any extra
	       attribute they have locally attached to an OP.  It is also
	       assured to first fire for the parent OP and then for its kids.

	       When you replace this variable, it is considered a good
	       practice to store the possibly previously installed hook and
	       that you recall it inside your own.

		       Perl_ophook_t   PL_opfreehook

       PL_peepp
	       Pointer to the per-subroutine peephole optimiser.  This is a
	       function that gets called at the end of compilation of a Perl
	       subroutine (or equivalently independent piece of Perl code) to
	       perform fixups of some ops and to perform small-scale
	       optimisations.  The function is called once for each subroutine
	       that is compiled, and is passed, as sole parameter, a pointer
	       to the op that is the entry point to the subroutine.  It
	       modifies the op tree in place.

	       The peephole optimiser should never be completely replaced.
	       Rather, add code to it by wrapping the existing optimiser.  The
	       basic way to do this can be seen in "Compile pass 3: peephole
	       optimization" in perlguts.  If the new code wishes to operate
	       on ops throughout the subroutine's structure, rather than just
	       at the top level, it is likely to be more convenient to wrap
	       the "PL_rpeepp" hook.

		       peep_t  PL_peepp

       PL_rpeepp
	       Pointer to the recursive peephole optimiser.  This is a
	       function that gets called at the end of compilation of a Perl
	       subroutine (or equivalently independent piece of Perl code) to
	       perform fixups of some ops and to perform small-scale
	       optimisations.  The function is called once for each chain of
	       ops linked through their "op_next" fields; it is recursively
	       called to handle each side chain.  It is passed, as sole
	       parameter, a pointer to the op that is at the head of the
	       chain.  It modifies the op tree in place.

	       The peephole optimiser should never be completely replaced.
	       Rather, add code to it by wrapping the existing optimiser.  The
	       basic way to do this can be seen in "Compile pass 3: peephole
	       optimization" in perlguts.  If the new code wishes to operate
	       only on ops at a subroutine's top level, rather than throughout
	       the structure, it is likely to be more convenient to wrap the
	       "PL_peepp" hook.

		       peep_t  PL_rpeepp

       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

REGEXP Functions
       SvRX    Convenience macro to get the REGEXP from a SV. This is
	       approximately equivalent to the following snippet:

		   if (SvMAGICAL(sv))
		       mg_get(sv);
		   if (SvROK(sv))
		       sv = MUTABLE_SV(SvRV(sv));
		   if (SvTYPE(sv) == SVt_REGEXP)
		       return (REGEXP*) sv;

	       NULL will be returned if a REGEXP* is not found.

		       REGEXP * SvRX(SV *sv)

       SvRXOK  Returns a boolean indicating whether the SV (or the one it
	       references) is a REGEXP.

	       If you want to do something with the REGEXP* later use SvRX
	       instead and check for NULL.

		       bool    SvRXOK(SV* sv)

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 "dORIGMARK".

			       dMARK;

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

			       dORIGMARK;

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

			       dSP;

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

		       void    EXTEND(SP, int nitems)

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

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

		       void    PUSHi(IV iv)

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

		       void    PUSHMARK(SP)

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

		       void    PUSHmortal()

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

		       void    PUSHn(NV nv)

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

		       void    PUSHp(char* str, STRLEN len)

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

		       void    PUSHs(SV* sv)

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

		       void    PUSHu(UV uv)

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

			       PUTBACK;

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

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

			       SPAGAIN;

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

		       void    XPUSHi(IV iv)

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

		       void    XPUSHmortal()

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

		       void    XPUSHn(NV nv)

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

		       void    XPUSHp(char* str, STRLEN len)

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

		       void    XPUSHs(SV* sv)

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

		       void    XPUSHu(UV uv)

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

		       void    XSRETURN(int nitems)

       XSRETURN_EMPTY
	       Return an empty list from an XSUB immediately.

			       XSRETURN_EMPTY;

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

		       void    XSRETURN_IV(IV iv)

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

			       XSRETURN_NO;

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

		       void    XSRETURN_NV(NV nv)

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

		       void    XSRETURN_PV(char* str)

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

			       XSRETURN_UNDEF;

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

		       void    XSRETURN_UV(IV uv)

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

			       XSRETURN_YES;

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

		       void    XST_mIV(int pos, IV iv)

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

		       void    XST_mNO(int pos)

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

		       void    XST_mNV(int pos, NV nv)

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

		       void    XST_mPV(int pos, char* str)

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

		       void    XST_mUNDEF(int pos)

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

		       void    XST_mYES(int pos)

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

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

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

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

       SVt_PVAV
	       Type flag for arrays.  See "svtype".

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

       SVt_PVHV
	       Type flag for hashes.  See "svtype".

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

SV Manipulation Functions
       boolSV  Returns a true SV if "b" is a true value, or a false SV if "b"
	       is 0.

	       See also "PL_sv_yes" and "PL_sv_no".

		       SV *    boolSV(bool b)

       croak_xs_usage
	       A specialised variant of "croak()" for emitting the usage
	       message for xsubs

		   croak_xs_usage(cv, "eee_yow");

	       works out the package name and subroutine name from "cv", and
	       then calls "croak()". Hence if "cv" is &ouch::awk, it would
	       call "croak" as:

		   Perl_croak(aTHX_ "Usage: %"SVf"::%"SVf"(%s)", "ouch" "awk", "eee_yow");

		       void    croak_xs_usage(const CV *const cv,
					      const char *const params)

       get_sv  Returns the SV of the specified Perl scalar.  "flags" are
	       passed to "gv_fetchpv". If "GV_ADD" is set and the Perl
	       variable does not exist then it will be created.	 If "flags" is
	       zero 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 flags)

       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 spot just after the last character in
	       the string which is in the SV, where there is usually a
	       trailing null (even though Perl scalars do not strictly require
	       it).  See "SvCUR".  Access the character as *(SvEND(sv)).

	       Warning: If "SvCUR" is equal to "SvLEN", then "SvEND" points to
	       unallocated memory.

		       char*   SvEND(SV* sv)

       SvGAMAGIC
	       Returns true if the SV has get magic or overloading.  If either
	       is true then the scalar is active data, and has the potential
	       to return a new value every time it is accessed.	 Hence you
	       must be careful to only read it once per user logical operation
	       and work with that returned value.  If neither is true then the
	       scalar's value cannot change unless written to.

		       U32     SvGAMAGIC(SV* sv)

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

		       char *  SvGROW(SV* sv, STRLEN len)

       SvIOK   Returns a 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" instead.

		       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
	       assignment to "SvIVX".

		       void    SvIV_set(SV* sv, IV val)

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

		       STRLEN  SvLEN(SV* sv)

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

		       void    SvLEN_set(SV* sv, STRLEN len)

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

		       void    SvMAGIC_set(SV* sv, MAGIC* val)

       SvNIOK  Returns a U32 value indicating whether the SV contains a
	       number, integer or double.

		       U32     SvNIOK(SV* sv)

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

		       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 private setting.  Use "SvNOK" instead.

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

		       NV      SvNV_nomg(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 defined.
	       This is only meaningful for scalars.

		       U32     SvOK(SV* sv)

       SvOOK   Returns a U32 indicating whether the pointer to the string
	       buffer is offset.  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
	       actually "SvOOK_offset()" bytes before SvPVX.  This offset used
	       to be stored in SvIVX, but is now stored within the spare part
	       of the buffer.

		       U32     SvOOK(SV* sv)

       SvOOK_offset
	       Reads into len the offset from SvPVX back to the true start of
	       the allocated buffer, which will be non-zero if "sv_chop" has
	       been used to efficiently remove characters from start of the
	       buffer.	Implemented as a macro, which takes the address of
	       len, which must be of type "STRLEN".  Evaluates sv more than
	       once.  Sets len to 0 if "SvOOK(sv)" is false.

		       void    SvOOK_offset(NN SV*sv, STRLEN len)

       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"
	       instead.

		       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.  Guarantees to evaluate sv only once; use the more
	       efficient "SvPVbyte" otherwise.

		       char*   SvPVbytex(SV* sv, STRLEN len)

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

		       char*   SvPVbytex_force(SV* sv, STRLEN len)

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

		       char*   SvPVbyte_force(SV* sv, STRLEN len)

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

		       char*   SvPVbyte_nolen(SV* sv)

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

		       char*   SvPVutf8(SV* sv, STRLEN len)

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

		       char*   SvPVutf8x(SV* sv, STRLEN len)

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

		       char*   SvPVutf8x_force(SV* sv, STRLEN len)

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

		       char*   SvPVutf8_force(SV* sv, STRLEN len)

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

		       char*   SvPVutf8_nolen(SV* sv)

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

	       This is also used to store the name of an autoloaded subroutine
	       in an XS AUTOLOAD routine.  See "Autoloading with XSUBs" in
	       perlguts.

		       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 "SvPV".

		       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_nomg_nolen
	       Like "SvPV_nolen" but doesn't process magic.

		       char*   SvPV_nomg_nolen(SV* sv)

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

		       void    SvPV_set(SV* sv, char* val)

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

		       U32     SvREFCNT(SV* sv)

       SvREFCNT_dec
	       Decrements the reference count of the given SV.

		       void    SvREFCNT_dec(SV* sv)

       SvREFCNT_inc
	       Increments the reference count of the given SV.

	       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, and if some input to the
	       current expression is tainted--usually a variable, but possibly
	       also implicit inputs such as locale settings.  "SvTAINT"
	       propagates that taintedness to the outputs of an expression in
	       a pessimistic fashion; i.e., without paying attention to
	       precisely which outputs are influenced by which inputs.

		       void    SvTAINT(SV* sv)

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

		       bool    SvTAINTED(SV* sv)

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

		       void    SvTAINTED_off(SV* sv)

       SvTAINTED_on
	       Marks an SV as tainted if tainting is enabled.

		       void    SvTAINTED_on(SV* sv)

       SvTRUE  Returns a boolean indicating whether Perl would evaluate the SV
	       as true or false.  See SvOK() for a defined/undefined test.
	       Handles 'get' magic unless the scalar is already SvPOK, SvIOK
	       or SvNOK (the public, not the private flags).

		       bool    SvTRUE(SV* sv)

       SvTRUE_nomg
	       Returns a boolean indicating whether Perl would evaluate the SV
	       as true or false.  See SvOK() for a defined/undefined test.
	       Does not handle 'get' magic.

		       bool    SvTRUE_nomg(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 the UTF-8 status of an SV.  If
	       things are set-up properly, this indicates whether or not 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 (the data is not changed, just
	       the flag).  Do not use frivolously.

		       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)

       SvVOK   Returns a boolean indicating whether the SV contains a
	       v-string.

		       bool    SvVOK(SV* sv)

       sv_catpvn_nomg
	       Like "sv_catpvn" but doesn't process magic.

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

       sv_catpv_nomg
	       Like "sv_catpv" but doesn't process magic.

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

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

		       void    sv_catsv_nomg(SV* dsv, SV* ssv)

       sv_derived_from
	       Exactly like "sv_derived_from_pv", but doesn't take a "flags"
	       parameter.

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

       sv_derived_from_pv
	       Exactly like "sv_derived_from_pvn", but takes a nul-terminated
	       string instead of a string/length pair.

		       bool    sv_derived_from_pv(SV* sv,
						  const char *const name,
						  U32 flags)

       sv_derived_from_pvn
	       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.

	       Currently, the only significant value for "flags" is SVf_UTF8.

		       bool    sv_derived_from_pvn(SV* sv,
						   const char *const name,
						   const STRLEN len, U32 flags)

       sv_derived_from_sv
	       Exactly like "sv_derived_from_pvn", but takes the name string
	       in the form of an SV instead of a string/length pair.

		       bool    sv_derived_from_sv(SV* sv, SV *namesv,
						  U32 flags)

       sv_does Like "sv_does_pv", but doesn't take a "flags" parameter.

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

       sv_does_pv
	       Like "sv_does_sv", but takes a nul-terminated string instead of
	       an SV.

		       bool    sv_does_pv(SV* sv, const char *const name,
					  U32 flags)

       sv_does_pvn
	       Like "sv_does_sv", but takes a string/length pair instead of an
	       SV.

		       bool    sv_does_pvn(SV* sv, const char *const name,
					   const STRLEN len, U32 flags)

       sv_does_sv
	       Returns a boolean indicating whether the SV performs a
	       specific, named role.  The SV can be a Perl object or the name
	       of a Perl class.

		       bool    sv_does_sv(SV* sv, SV* namesv, U32 flags)

       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_utf8_upgrade_nomg
	       Like sv_utf8_upgrade, but doesn't do magic on "sv".

		       STRLEN  sv_utf8_upgrade_nomg(NN SV *sv)

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.  Get-magic is ignored.

		       I32     looks_like_number(SV *const sv)

       newRV_noinc
	       Creates an RV wrapper for an SV.	 The reference count for the
	       original SV is not incremented.

		       SV*     newRV_noinc(SV *const 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
	       perlhacktips).  The older API is still there for use in XS
	       modules supporting older perls.

		       SV*     newSV(const 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 *const hek)

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

		       SV*     newSViv(const 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(const 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 *const s, const STRLEN len)

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

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

       newSVpvn
	       Creates a new SV and copies a buffer into it, which may contain
	       NUL characters ("\0") and other binary data.  The reference
	       count for the SV is set to 1.  Note that if "len" is zero, Perl
	       will create a zero length (Perl) string.	 You are responsible
	       for ensuring that the source buffer is at least "len" bytes
	       long.  If the "buffer" argument is NULL the new SV will be
	       undefined.

		       SV*     newSVpvn(const char *const s, const 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 "sv_2mortal()" is
	       called on the result before returning.  If "SVf_UTF8" is set,
	       "s" is considered to be in UTF-8 and the "SVf_UTF8" flag 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 *const s,
					      const STRLEN len,
					      const 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 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)

       newSVpv_share
	       Like "newSVpvn_share", but takes a nul-terminated string
	       instead of a string/length pair.

		       SV*     newSVpv_share(const char* s, U32 hash)

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

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

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

		       SV*     newSVsv(SV *const 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(const 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(const svtype type)

       sv_2bool
	       This macro is only used by sv_true() or its macro equivalent,
	       and only if the latter's argument is neither SvPOK, SvIOK nor
	       SvNOK.  It calls sv_2bool_flags with the SV_GMAGIC flag.

		       bool    sv_2bool(SV *const sv)

       sv_2bool_flags
	       This function is only used by sv_true() and friends,  and only
	       if the latter's argument is neither SvPOK, SvIOK nor SvNOK.  If
	       the flags contain SV_GMAGIC, then it does an mg_get() first.

		       bool    sv_2bool_flags(SV *const sv, const I32 flags)

       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
	       gv_fetchsv.

		       CV*     sv_2cv(SV* sv, HV **const st, GV **const gvp,
				      const 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.

	       'Get' magic is ignored on the sv passed in, but will be called
	       on "SvRV(sv)" if sv is an RV.

		       IO*     sv_2io(SV *const 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 *const sv, const 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 *const sv)

       sv_2nv_flags
	       Return the num value of an SV, doing any necessary string or
	       integer conversion.  If flags includes SV_GMAGIC, does an
	       mg_get() first.	Normally used via the "SvNV(sv)" and
	       "SvNVx(sv)" macros.

		       NV      sv_2nv_flags(SV *const sv, const I32 flags)

       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 *const 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 *const 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 necessary.  Normally invoked
	       via the "SvPV_flags" macro.  "sv_2pv()" and "sv_2pv_nomg"
	       usually end up here too.

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

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

		       int     sv_backoff(SV *const 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 *const sv, HV *const 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 *const 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 *const sv, const char *const pat,
					 ...)

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

		       void    sv_catpvf_mg(SV *const sv,
					    const char *const 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 *dsv, const char *sstr, 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 the "SV_SMAGIC" bit set, will
	       "mg_set" on "dsv" afterwards if appropriate.  "sv_catpvn" and
	       "sv_catpvn_nomg" are implemented in terms of this function.

		       void    sv_catpvn_flags(SV *const dstr,
					       const char *sstr,
					       const STRLEN len,
					       const 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_catpvs_flags
	       Like "sv_catpvn_flags", but takes a literal string instead of a
	       string/length pair.

		       void    sv_catpvs_flags(SV* sv, const char* s,
					       I32 flags)

       sv_catpvs_mg
	       Like "sv_catpvn_mg", but takes a literal string instead of a
	       string/length pair.

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

       sv_catpvs_nomg
	       Like "sv_catpvn_nomg", but takes a literal string instead of a
	       string/length pair.

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

       sv_catpv_flags
	       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.	If "flags" has the "SV_SMAGIC"
	       bit set, will "mg_set" on the modified SV if appropriate.

		       void    sv_catpv_flags(SV *dstr, const char *sstr,
					      const I32 flags)

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

		       void    sv_catpv_mg(SV *const sv, const char *const 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 *dstr, SV *sstr)

       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 "ssv", if
	       appropriate, before reading it.	If the "flags" contain
	       "SV_SMAGIC", "mg_set" will be called on the modified SV
	       afterward, if appropriate.  "sv_catsv" and "sv_catsv_nomg" are
	       implemented in terms of this function.

		       void    sv_catsv_flags(SV *const dsv, SV *const ssv,
					      const 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.

	       The unfortunate similarity of this function's name to that of
	       Perl's "chop" operator is strictly coincidental.	 This function
	       works from the left; "chop" works from the right.

		       void    sv_chop(SV *const sv, const char *const 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 *const orig_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 *const sv1, SV *const sv2)

       sv_cmp_flags
	       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 and will coerce its args to strings if necessary.	If the
	       flags include SV_GMAGIC, it handles get magic.  See also
	       "sv_cmp_locale_flags".

		       I32     sv_cmp_flags(SV *const sv1, SV *const sv2,
					    const U32 flags)

       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 *const sv1, SV *const sv2)

       sv_cmp_locale_flags
	       Compares the strings in two SVs in a locale-aware manner.  Is
	       UTF-8 and 'use bytes' aware and will coerce its args to strings
	       if necessary.  If the flags contain SV_GMAGIC, it handles get
	       magic.  See also "sv_cmp_flags".

		       I32     sv_cmp_locale_flags(SV *const sv1,
						   SV *const sv2,
						   const U32 flags)

       sv_collxfrm
	       This calls "sv_collxfrm_flags" with the SV_GMAGIC flag.	See
	       "sv_collxfrm_flags".

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

       sv_collxfrm_flags
	       Add Collate Transform magic to an SV if it doesn't already have
	       it.  If the flags contain SV_GMAGIC, it handles get-magic.

	       Any scalar variable may carry PERL_MAGIC_collxfrm magic that
	       contains the scalar data of the variable, but transformed to
	       such a format that a normal memory comparison can be used to
	       compare the data according to the locale settings.

		       char*   sv_collxfrm_flags(SV *const sv,
						 STRLEN *const nxp,
						 I32 const flags)

       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 *const dsv, SV *const ssv)

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

		       void    sv_dec(SV *const sv)

       sv_dec_nomg
	       Auto-decrement of the value in the SV, doing string to numeric
	       conversion if necessary.	 Handles operator overloading.	Skips
	       handling 'get' magic.

		       void    sv_dec_nomg(SV *const 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_eq_flags
	       Returns a boolean indicating whether the strings in the two SVs
	       are identical.  Is UTF-8 and 'use bytes' aware and coerces its
	       args to strings if necessary.  If the flags include SV_GMAGIC,
	       it handles get-magic, too.

		       I32     sv_eq_flags(SV* sv1, SV* sv2, const U32 flags)

       sv_force_normal_flags
	       Undo various types of fakery on an SV: if the PV is a shared
	       string, make a private copy; if we're a ref, stop refing; if
	       we're a glob, downgrade to an xpvmg; if we're a copy-on-write
	       scalar, this is the on-write time when we do the copy, and is
	       also used locally.  If "SV_COW_DROP_PV" is set then a copy-on-
	       write scalar drops its PV buffer (if any) and becomes SvPOK_off
	       rather than making a copy.  (Used where this scalar is about to
	       be set to some other value.)  In addition, the "flags"
	       parameter gets passed to "sv_unref_flags()" when unreffing.
	       "sv_force_normal" calls this function with flags set to 0.

		       void    sv_force_normal_flags(SV *const sv,
						     const 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 *const 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 *const sv, PerlIO *const 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 *const sv, STRLEN newlen)

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

		       void    sv_inc(SV *const sv)

       sv_inc_nomg
	       Auto-increment of the value in the SV, doing string to numeric
	       conversion if necessary.	 Handles operator overloading.	Skips
	       handling 'get' magic.

		       void    sv_inc_nomg(SV *const sv)

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

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

       sv_insert_flags
	       Same as "sv_insert", but the extra "flags" are passed to the
	       "SvPV_force_flags" that applies to "bigstr".

		       void    sv_insert_flags(SV *const bigstr,
					       const STRLEN offset,
					       const STRLEN len,
					       const char *const little,
					       const STRLEN littlelen,
					       const U32 flags)

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

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

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

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

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

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

	       Use "sv_pos_u2b_flags" in preference, which correctly handles
	       strings longer than 2Gb.

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

       sv_pos_u2b_flags
	       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 type coercion.
	       flags is passed to "SvPV_flags", and usually should be
	       "SV_GMAGIC|SV_CONST_RETURN" to handle magic.

		       STRLEN  sv_pos_u2b_flags(SV *const sv, STRLEN uoffset,
						STRLEN *const lenp, U32 flags)

       sv_pvbyten_force
	       The backend for the "SvPVbytex_force" macro.  Always use the
	       macro instead.

		       char*   sv_pvbyten_force(SV *const sv, STRLEN *const 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 *const sv,
						  STRLEN *const lp,
						  const I32 flags)

       sv_pvutf8n_force
	       The backend for the "SvPVutf8x_force" macro.  Always use the
	       macro instead.

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

       sv_reftype
	       Returns a string describing what the SV is a reference to.

		       const char* sv_reftype(const SV *const sv, const int ob)

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

		       void    sv_replace(SV *const sv, SV *const nsv)

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

		       void    sv_reset(const char* s, HV *const 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.  If the RV is
	       magical, set magic will be called after the RV is cleared.

		       SV*     sv_rvweaken(SV *const sv)

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

		       void    sv_setiv(SV *const sv, const IV num)

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

		       void    sv_setiv_mg(SV *const sv, const 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 *const sv, const NV num)

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

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

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

		       void    sv_setpvf_mg(SV *const sv,
					    const char *const 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 *const sv, const IV num)

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

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

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

		       void    sv_setpvn_mg(SV *const sv,
					    const char *const ptr,
					    const 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_setpvs_mg
	       Like "sv_setpvn_mg", but takes a literal string instead of a
	       string/length pair.

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

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

		       void    sv_setpv_mg(SV *const sv, const char *const 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 *const rv,
					    const char *const classname,
					    const 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 *const rv,
					    const char *const classname,
					    const 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 *const rv,
					    const char *const classname,
					    void *const pv)

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

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

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

       sv_setref_pvs
	       Like "sv_setref_pvn", but takes a literal string instead of a
	       string/length pair.

		       SV *    sv_setref_pvs(const char* s)

       sv_setref_uv
	       Copies an unsigned integer into a new SV, optionally blessing
	       the SV.	The "rv" argument will be upgraded to an RV.  That RV
	       will be modified to point to the new SV.	 The "classname"
	       argument indicates the package for the blessing.	 Set
	       "classname" to "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 *const rv,
					    const char *const classname,
					    const 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 *dstr, SV *sstr)

       sv_setsv_flags
	       Copies the contents of the source SV "ssv" into the destination
	       SV "dsv".  The source SV may be destroyed if it is mortal, so
	       don't use this function if the source SV needs to be reused.
	       Does not handle 'set' magic.  Loosely speaking, it performs a
	       copy-by-value, obliterating any previous content of the
	       destination.  If the "flags" parameter has the "SV_GMAGIC" bit
	       set, will "mg_get" on "ssv" if appropriate, else not.  If the
	       "flags" parameter has the "NOSTEAL" bit set then the buffers of
	       temps will not be stolen.  <sv_setsv> and "sv_setsv_nomg" are
	       implemented in terms of this function.

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

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

		       void    sv_setsv_flags(SV *dstr, SV *sstr,
					      const I32 flags)

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

		       void    sv_setsv_mg(SV *const dstr, SV *const 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 *const sv, const UV num)

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

		       void    sv_setuv_mg(SV *const sv, const UV u)

       sv_tainted
	       Test an SV for taintedness.  Use "SvTAINTED" instead.

		       bool    sv_tainted(SV *const 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 *const sv)

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

		       int     sv_unmagic(SV *const sv, const int type)

       sv_unmagicext
	       Removes all magic of type "type" with the specified "vtbl" from
	       an SV.

		       int     sv_unmagicext(SV *const sv, const int type,
					     MGVTBL *vtbl)

       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 *const ref, const U32 flags)

       sv_untaint
	       Untaint an SV.  Use "SvTAINTED_off" instead.

		       void    sv_untaint(SV *const 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.  It croaks if the SV is already in
	       a more complex form than requested.  You generally want to use
	       the "SvUPGRADE" macro wrapper, which checks the type before
	       calling "sv_upgrade", and hence does not croak.	See also
	       "svtype".

		       void    sv_upgrade(SV *const sv, svtype new_type)

       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".	It must be the start of a
	       mallocked block of memory, and not a pointer to the middle of
	       it.  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_TRAILING_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 *const sv, char* ptr,
					       const STRLEN len,
					       const 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 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 *const sv)

       sv_utf8_downgrade
	       Attempts to convert the PV of an SV from characters to bytes.
	       If the PV contains a character that cannot fit in a 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 *const sv,
						 const 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 *const 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.	Will "mg_get" on "sv"
	       if appropriate.	Always sets the SvUTF8 flag to avoid future
	       validity checks even if the whole string is the same in UTF-8
	       as not.	Returns the number of bytes in the converted string

	       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 are
	       invariant in UTF-8.  If "flags" has "SV_GMAGIC" bit set, will
	       "mg_get" on "sv" if appropriate, else not.  Returns the number
	       of bytes in the converted string "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 *const sv,
						     const I32 flags)

       sv_utf8_upgrade_nomg
	       Like sv_utf8_upgrade, but doesn't do magic on "sv".

		       STRLEN  sv_utf8_upgrade_nomg(SV *sv)

       sv_vcatpvf
	       Processes its arguments like "vsprintf" and appends the
	       formatted output to an SV.  Does not handle 'set' magic.	 See
	       "sv_vcatpvf_mg".

	       Usually used via its frontend "sv_catpvf".

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

	       Usually used via one of its frontends "sv_vcatpvf" and
	       "sv_vcatpvf_mg".

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

Unicode Support
       bytes_cmp_utf8
	       Compares the sequence of characters (stored as octets) in "b",
	       "blen" with the sequence of characters (stored as UTF-8) in
	       "u", "ulen". Returns 0 if they are equal, -1 or -2 if the first
	       string is less than the second string, +1 or +2 if the first
	       string is greater than the second string.

	       -1 or +1 is returned if the shorter string was identical to the
	       start of the longer string. -2 or +2 is returned if the was a
	       difference between characters within the strings.

		       int     bytes_cmp_utf8(const U8 *b, STRLEN blen,
					      const U8 *u, STRLEN ulen)

       bytes_from_utf8
	       Converts a string "s" of length "len" from UTF-8 into native
	       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 consisted entirely of characters that are
	       invariant in utf8 (i.e., US-ASCII on non-EBCDIC machines).

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

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

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

	       A NUL character will be written after the end of the string.

	       If you want to convert to UTF-8 from encodings other than the
	       native (Latin1 or EBCDIC), see "sv_recode_to_utf8"().

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

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

       foldEQ_utf8
	       Returns true if the leading portions of the strings "s1" and
	       "s2" (either or both of which may be in UTF-8) are the same
	       case-insensitively; false otherwise.  How far into the strings
	       to compare is determined by other input parameters.

	       If "u1" is true, the string "s1" is assumed to be in
	       UTF-8-encoded Unicode; otherwise it is assumed to be in native
	       8-bit encoding.	Correspondingly for "u2" with respect to "s2".

	       If the byte length "l1" is non-zero, it says how far into "s1"
	       to check for fold equality.  In other words, "s1"+"l1" will be
	       used as a goal to reach.	 The scan will not be considered to be
	       a match unless the goal is reached, and scanning won't continue
	       past that goal.	Correspondingly for "l2" with respect to "s2".

	       If "pe1" is non-NULL and the pointer it points to is not NULL,
	       that pointer is considered an end pointer beyond which scanning
	       of "s1" will not continue under any circumstances.  This means
	       that if both "l1" and "pe1" are specified, and "pe1" is less
	       than "s1"+"l1", the match will never be successful because it
	       can never get as far as its goal (and in fact is asserted
	       against).  Correspondingly for "pe2" with respect to "s2".

	       At least one of "s1" and "s2" must have a goal (at least one of
	       "l1" and "l2" must be non-zero), and if both do, both have to
	       be reached for a successful match.   Also, if the fold of a
	       character is multiple characters, all of them must be matched
	       (see tr21 reference below for 'folding').

	       Upon a successful match, if "pe1" is non-NULL, it will be set
	       to point to the beginning of the next character of "s1" beyond
	       what was matched.  Correspondingly for "pe2" and "s2".

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

		       I32     foldEQ_utf8(const char *s1, char **pe1, UV l1,
					   bool u1, const char *s2, char **pe2,
					   UV l2, bool u2)

       is_ascii_string
	       Returns true if the first "len" bytes of the string "s" are the
	       same whether or not the string is encoded in UTF-8 (or UTF-
	       EBCDIC on EBCDIC machines).  That is, if they are invariant.
	       On ASCII-ish machines, only ASCII characters fit this
	       definition, hence the function's name.

	       If "len" is 0, it will be calculated using strlen(s).

	       See also "is_utf8_string"(), "is_utf8_string_loclen"(), and
	       "is_utf8_string_loc"().

		       bool    is_ascii_string(const U8 *s, STRLEN len)

       is_utf8_char
	       DEPRECATED!

	       Tests if some arbitrary number of bytes begins in a valid UTF-8
	       character.  Note that an INVARIANT (i.e. ASCII on non-EBCDIC
	       machines) 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.

	       This function is deprecated due to the possibility that
	       malformed input could cause reading beyond the end of the input
	       buffer.	Use "is_utf8_char_buf" instead.

		       STRLEN  is_utf8_char(const U8 *s)

       is_utf8_char_buf
	       Returns the number of bytes that comprise the first UTF-8
	       encoded character in buffer "buf".  "buf_end" should point to
	       one position beyond the end of the buffer.  0 is returned if
	       "buf" does not point to a complete, valid UTF-8 encoded
	       character.

	       Note that an INVARIANT character (i.e. ASCII on non-EBCDIC
	       machines) is a valid UTF-8 character.

		       STRLEN  is_utf8_char_buf(const U8 *buf,
						const U8 *buf_end)

       is_utf8_string
	       Returns true if the first "len" bytes of string "s" form a
	       valid UTF-8 string, false otherwise.  If "len" is 0, it will be
	       calculated using strlen(s) (which means if you use this option,
	       that "s" has to have a terminating NUL byte).  Note that all
	       characters being ASCII constitute 'a valid UTF-8 string'.

	       See also "is_ascii_string"(), "is_utf8_string_loclen"(), and
	       "is_utf8_string_loc"().

		       bool    is_utf8_string(const 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(const U8 *s, STRLEN len,
						  const U8 **p)

       is_utf8_string_loclen
	       Like "is_utf8_string"() but stores the location of the failure
	       (in the case of "utf8ness failure") or the location "s"+"len"
	       (in the case of "utf8ness success") in the "ep", and the number
	       of UTF-8 encoded characters in the "el".

	       See also "is_utf8_string_loc"() and "is_utf8_string"().

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

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

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

	       The pointer to the PV of the "dsv" is returned.

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

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

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

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

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

	       If the sv already is UTF-8 (or if it is not POK), or if the
	       encoding is not a reference, nothing is done to the sv.	If the
	       encoding is not an "Encode::XS" Encoding object, bad things
	       will happen.  (See lib/encoding.pm and Encode.)

	       The PV of the sv is returned.

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

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

	       The "flags" argument is as in "pv_uni_display"().

	       The pointer to the PV of the "dsv" is returned.

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

       to_utf8_case
	       The "p" contains the pointer to the UTF-8 string encoding the
	       character that is being converted.  This routine assumes that
	       the character at "p" is well-formed.

	       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 in
	       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(const U8 *p, U8* ustrp,
					    STRLEN *lenp, SV **swashp,
					    const char *normal,
					    const 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.)

	       The character at "p" is assumed by this routine to be well-
	       formed.

		       UV      to_utf8_fold(const 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.)

	       The character at "p" is assumed by this routine to be well-
	       formed.

		       UV      to_utf8_lower(const 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.)

	       The character at "p" is assumed by this routine to be well-
	       formed.

		       UV      to_utf8_title(const 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.)

	       The character at "p" is assumed by this routine to be well-
	       formed.

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

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

	       "length" and "flags" are the same as "utf8n_to_uvuni"().

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

       utf8n_to_uvuni
	       Bottom level UTF-8 decode routine.  Returns the code point
	       value of the first character in the string "s", which is
	       assumed to be in UTF-8 (or UTF-EBCDIC) encoding, and no longer
	       than "curlen" bytes; *retlen (if "retlen" isn't NULL) will be
	       set to the length, in bytes, of that character.

	       The value of "flags" determines the behavior when "s" does not
	       point to a well-formed UTF-8 character.	If "flags" is 0, when
	       a malformation is found, zero is returned and *retlen is set so
	       that ("s" + *retlen) is the next possible position in "s" that
	       could begin a non-malformed character.  Also, if UTF-8 warnings
	       haven't been lexically disabled, a warning is raised.

	       Various ALLOW flags can be set in "flags" to allow (and not
	       warn on) individual types of malformations, such as the
	       sequence being overlong (that is, when there is a shorter
	       sequence that can express the same code point; overlong
	       sequences are expressly forbidden in the UTF-8 standard due to
	       potential security issues).  Another malformation example is
	       the first byte of a character not being a legal first byte.
	       See utf8.h for the list of such flags.  For allowed 0 length
	       strings, this function returns 0; for allowed overlong
	       sequences, the computed code point is returned; for all other
	       allowed malformations, the Unicode REPLACEMENT CHARACTER is
	       returned, as these have no determinable reasonable value.

	       The UTF8_CHECK_ONLY flag overrides the behavior when a non-
	       allowed (by other flags) malformation is found.	If this flag
	       is set, the routine assumes that the caller will raise a
	       warning, and this function will silently just set "retlen" to
	       "-1" and return zero.

	       Certain code points are considered problematic.	These are
	       Unicode surrogates, Unicode non-characters, and code points
	       above the Unicode maximum of 0x10FFFF.  By default these are
	       considered regular code points, but certain situations warrant
	       special handling for them.  If "flags" contains
	       UTF8_DISALLOW_ILLEGAL_INTERCHANGE, all three classes are
	       treated as malformations and handled as such.  The flags
	       UTF8_DISALLOW_SURROGATE, UTF8_DISALLOW_NONCHAR, and
	       UTF8_DISALLOW_SUPER (meaning above the legal Unicode maximum)
	       can be set to disallow these categories individually.

	       The flags UTF8_WARN_ILLEGAL_INTERCHANGE, UTF8_WARN_SURROGATE,
	       UTF8_WARN_NONCHAR, and UTF8_WARN_SUPER will cause warning
	       messages to be raised for their respective categories, but
	       otherwise the code points are considered valid (not
	       malformations).	To get a category to both be treated as a
	       malformation and raise a warning, specify both the WARN and
	       DISALLOW flags.	(But note that warnings are not raised if
	       lexically disabled nor if UTF8_CHECK_ONLY is also specified.)

	       Very large code points (above 0x7FFF_FFFF) are considered more
	       problematic than the others that are above the Unicode legal
	       maximum.	 There are several reasons: they requre at least 32
	       bits to represent them on ASCII platforms, are not
	       representable at all on EBCDIC platforms, and the original
	       UTF-8 specification never went above this number (the current
	       0x10FFFF limit was imposed later).  (The smaller ones, those
	       that fit into 32 bits, are representable by a UV on ASCII
	       platforms, but not by an IV, which means that the number of
	       operations that can be performed on them is quite restricted.)
	       The UTF-8 encoding on ASCII platforms for these large code
	       points begins with a byte containing 0xFE or 0xFF.  The
	       UTF8_DISALLOW_FE_FF flag will cause them to be treated as
	       malformations, while allowing smaller above-Unicode code
	       points.	(Of course UTF8_DISALLOW_SUPER will treat all above-
	       Unicode code points, including these, as malformations.)
	       Similarly, UTF8_WARN_FE_FF acts just like the other WARN flags,
	       but applies just to these code points.

	       All other code points corresponding to Unicode characters,
	       including private use and those yet to be assigned, are never
	       considered malformed and never warn.

	       Most code should use "utf8_to_uvchr_buf"() rather than call
	       this directly.

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

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

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

		       IV      utf8_distance(const U8 *a, const U8 *b)

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

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

		       U8*     utf8_hop(const 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(const U8* s, const U8 *e)

       utf8_to_bytes
	       Converts a string "s" of length "len" from UTF-8 into native
	       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
	       DEPRECATED!

	       Returns the native 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.

	       Some, but not all, UTF-8 malformations are detected, and in
	       fact, some malformed input could cause reading beyond the end
	       of the input buffer, which is why this function is deprecated.
	       Use "utf8_to_uvchr_buf" instead.

	       If "s" points to one of the detected malformations, and UTF8
	       warnings are enabled, zero is returned and *retlen is set (if
	       "retlen" isn't NULL) to -1.  If those warnings are off, the
	       computed value if well-defined (or the Unicode REPLACEMENT
	       CHARACTER, if not) is silently returned, and *retlen is set (if
	       "retlen" isn't NULL) so that ("s" + *retlen) is the next
	       possible position in "s" that could begin a non-malformed
	       character.  See "utf8n_to_uvuni" for details on when the
	       REPLACEMENT CHARACTER is returned.

		       UV      utf8_to_uvchr(const U8 *s, STRLEN *retlen)

       utf8_to_uvchr_buf
	       Returns the native code point of the first character in the
	       string "s" which is assumed to be in UTF-8 encoding; "send"
	       points to 1 beyond the end of "s".  *retlen will be set to the
	       length, in bytes, of that character.

	       If "s" does not point to a well-formed UTF-8 character and UTF8
	       warnings are enabled, zero is returned and *retlen is set (if
	       "retlen" isn't NULL) to -1.  If those warnings are off, the
	       computed value if well-defined (or the Unicode REPLACEMENT
	       CHARACTER, if not) is silently returned, and *retlen is set (if
	       "retlen" isn't NULL) so that ("s" + *retlen) is the next
	       possible position in "s" that could begin a non-malformed
	       character.  See "utf8n_to_uvuni" for details on when the
	       REPLACEMENT CHARACTER is returned.

		       UV      utf8_to_uvchr_buf(const U8 *s, const U8 *send,
						 STRLEN *retlen)

       utf8_to_uvuni
	       DEPRECATED!

	       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 the returned UV is
	       considered an index into the Unicode semantic tables (e.g.
	       swashes).

	       Some, but not all, UTF-8 malformations are detected, and in
	       fact, some malformed input could cause reading beyond the end
	       of the input buffer, which is why this function is deprecated.
	       Use "utf8_to_uvuni_buf" instead.

	       If "s" points to one of the detected malformations, and UTF8
	       warnings are enabled, zero is returned and *retlen is set (if
	       "retlen" doesn't point to NULL) to -1.  If those warnings are
	       off, the computed value if well-defined (or the Unicode
	       REPLACEMENT CHARACTER, if not) is silently returned, and
	       *retlen is set (if "retlen" isn't NULL) so that ("s" + *retlen)
	       is the next possible position in "s" that could begin a non-
	       malformed character.  See "utf8n_to_uvuni" for details on when
	       the REPLACEMENT CHARACTER is returned.

		       UV      utf8_to_uvuni(const U8 *s, STRLEN *retlen)

       utf8_to_uvuni_buf
	       Returns the Unicode code point of the first character in the
	       string "s" which is assumed to be in UTF-8 encoding; "send"
	       points to 1 beyond the end of "s".  "retlen" will be set to the
	       length, in bytes, of that character.

	       This function should only be used when the 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 and UTF8
	       warnings are enabled, zero is returned and *retlen is set (if
	       "retlen" isn't NULL) to -1.  If those warnings are off, the
	       computed value if well-defined (or the Unicode REPLACEMENT
	       CHARACTER, if not) is silently returned, and *retlen is set (if
	       "retlen" isn't NULL) so that ("s" + *retlen) is the next
	       possible position in "s" that could begin a non-malformed
	       character.  See "utf8n_to_uvuni" for details on when the
	       REPLACEMENT CHARACTER is returned.

		       UV      utf8_to_uvuni_buf(const U8 *s, const U8 *send,
						 STRLEN *retlen)

       uvchr_to_utf8
	       Adds the UTF-8 representation of the Native code point "uv" to
	       the end of the string "d"; "d" should 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 code point "uv" to the end
	       of the string "d"; "d" should 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);

	       This is the recommended Unicode-aware way of saying

		   *(d++) = uv;

	       This function will convert to UTF-8 (and not warn) even code
	       points that aren't legal Unicode or are problematic, unless
	       "flags" contains one or more of the following flags:

	       If "uv" is a Unicode surrogate code point and
	       UNICODE_WARN_SURROGATE is set, the function will raise a
	       warning, provided UTF8 warnings are enabled.  If instead
	       UNICODE_DISALLOW_SURROGATE is set, the function will fail and
	       return NULL.  If both flags are set, the function will both
	       warn and return NULL.

	       The UNICODE_WARN_NONCHAR and UNICODE_DISALLOW_NONCHAR flags
	       correspondingly affect how the function handles a Unicode non-
	       character.  And, likewise for the UNICODE_WARN_SUPER and
	       UNICODE_DISALLOW_SUPER flags, and code points that are above
	       the Unicode maximum of 0x10FFFF.	 Code points above 0x7FFF_FFFF
	       (which are even less portable) can be warned and/or disallowed
	       even if other above-Unicode code points are accepted by the
	       UNICODE_WARN_FE_FF and UNICODE_DISALLOW_FE_FF flags.

	       And finally, the flag UNICODE_WARN_ILLEGAL_INTERCHANGE selects
	       all four of the above WARN flags; and
	       UNICODE_DISALLOW_ILLEGAL_INTERCHANGE selects all four DISALLOW
	       flags.

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

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

		       I32     ax

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

		       char*   CLASS

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

			       dAX;

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

			       dAXMARK;

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

			       dITEMS;

       dUNDERBAR
	       Sets up any variable needed by the "UNDERBAR" macro. It used to
	       define "padoff_du", but it is currently a noop. However, it is
	       strongly advised to still use it for ensuring past and future
	       compatibility.

			       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.

       XS      Macro to declare an XSUB and its C parameter list.  This is
	       handled by "xsubpp". It is the same as using the more explicit
	       XS_EXTERNAL macro.

       XS_APIVERSION_BOOTCHECK
	       Macro to verify that the perl api version an XS module has been
	       compiled against matches the api version of the perl
	       interpreter it's being loaded into.

			       XS_APIVERSION_BOOTCHECK;

       XS_EXTERNAL
	       Macro to declare an XSUB and its C parameter list explicitly
	       exporting the symbols.

       XS_INTERNAL
	       Macro to declare an XSUB and its C parameter list without
	       exporting the symbols.  This is handled by "xsubpp" and
	       generally preferable over exporting the XSUB symbols
	       unnecessarily.

       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 an XS interface to Perl's "die" function.

	       Take a sprintf-style format pattern and argument list.  These
	       are used to generate a string message.  If the message does not
	       end with a newline, then it will be extended with some
	       indication of the current location in the code, as described
	       for "mess_sv".

	       The error message will be used as an exception, by default
	       returning control to the nearest enclosing "eval", but subject
	       to modification by a $SIG{__DIE__} handler.  In any case, the
	       "croak" function never returns normally.

	       For historical reasons, if "pat" is null then the contents of
	       "ERRSV" ($@) will be used as an error message or object instead
	       of building an error message from arguments.  If you want to
	       throw a non-string object, or build an error message in an SV
	       yourself, it is preferable to use the "croak_sv" function,
	       which does not involve clobbering "ERRSV".

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

       croak_no_modify
	       Exactly equivalent to "Perl_croak(aTHX_ "%s", PL_no_modify)",
	       but generates terser object code than using "Perl_croak". Less
	       code used on exception code paths reduces CPU cache pressure.

		       void    croak_no_modify()

       croak_sv
	       This is an XS interface to Perl's "die" function.

	       "baseex" is the error message or object.	 If it is a reference,
	       it will be used as-is.  Otherwise it is used as a string, and
	       if it does not end with a newline then it will be extended with
	       some indication of the current location in the code, as
	       described for "mess_sv".

	       The error message or object will be used as an exception, by
	       default returning control to the nearest enclosing "eval", but
	       subject to modification by a $SIG{__DIE__} handler.  In any
	       case, the "croak_sv" function never returns normally.

	       To die with a simple string message, the "croak" function may
	       be more convenient.

		       void    croak_sv(SV *baseex)

       die     Behaves the same as "croak", except for the return type.	 It
	       should be used only where the "OP *" return type is required.
	       The function never actually returns.

		       OP *    die(const char *pat, ...)

       die_sv  Behaves the same as "croak_sv", except for the return type.  It
	       should be used only where the "OP *" return type is required.
	       The function never actually returns.

		       OP *    die_sv(SV *baseex)

       vcroak  This is an XS interface to Perl's "die" function.

	       "pat" and "args" are a sprintf-style format pattern and
	       encapsulated argument list.  These are used to generate a
	       string message.	If the message does not end with a newline,
	       then it will be extended with some indication of the current
	       location in the code, as described for "mess_sv".

	       The error message will be used as an exception, by default
	       returning control to the nearest enclosing "eval", but subject
	       to modification by a $SIG{__DIE__} handler.  In any case, the
	       "croak" function never returns normally.

	       For historical reasons, if "pat" is null then the contents of
	       "ERRSV" ($@) will be used as an error message or object instead
	       of building an error message from arguments.  If you want to
	       throw a non-string object, or build an error message in an SV
	       yourself, it is preferable to use the "croak_sv" function,
	       which does not involve clobbering "ERRSV".

		       void    vcroak(const char *pat, va_list *args)

       vwarn   This is an XS interface to Perl's "warn" function.

	       "pat" and "args" are a sprintf-style format pattern and
	       encapsulated argument list.  These are used to generate a
	       string message.	If the message does not end with a newline,
	       then it will be extended with some indication of the current
	       location in the code, as described for "mess_sv".

	       The error message or object will by default be written to
	       standard error, but this is subject to modification by a
	       $SIG{__WARN__} handler.

	       Unlike with "vcroak", "pat" is not permitted to be null.

		       void    vwarn(const char *pat, va_list *args)

       warn    This is an XS interface to Perl's "warn" function.

	       Take a sprintf-style format pattern and argument list.  These
	       are used to generate a string message.  If the message does not
	       end with a newline, then it will be extended with some
	       indication of the current location in the code, as described
	       for "mess_sv".

	       The error message or object will by default be written to
	       standard error, but this is subject to modification by a
	       $SIG{__WARN__} handler.

	       Unlike with "croak", "pat" is not permitted to be null.

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

       warn_sv This is an XS interface to Perl's "warn" function.

	       "baseex" is the error message or object.	 If it is a reference,
	       it will be used as-is.  Otherwise it is used as a string, and
	       if it does not end with a newline then it will be extended with
	       some indication of the current location in the code, as
	       described for "mess_sv".

	       The error message or object will by default be written to
	       standard error, but this is subject to modification by a
	       $SIG{__WARN__} handler.

	       To warn with a simple string message, the "warn" function may
	       be more convenient.

		       void    warn_sv(SV *baseex)

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

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

       GetVars
       Gv_AMupdate
       PerlIO_clearerr
       PerlIO_close
       PerlIO_context_layers
       PerlIO_eof
       PerlIO_error
       PerlIO_fileno
       PerlIO_fill
       PerlIO_flush
       PerlIO_get_base
       PerlIO_get_bufsiz
       PerlIO_get_cnt
       PerlIO_get_ptr
       PerlIO_read
       PerlIO_seek
       PerlIO_set_cnt
       PerlIO_set_ptrcnt
       PerlIO_setlinebuf
       PerlIO_stderr
       PerlIO_stdin
       PerlIO_stdout
       PerlIO_tell
       PerlIO_unread
       PerlIO_write
       Slab_Alloc
       Slab_Free
       _is_utf8_quotemeta
       amagic_call
       amagic_deref_call
       any_dup
       atfork_lock
       atfork_unlock
       av_arylen_p
       av_iter_p
       block_gimme
       call_atexit
       call_list
       calloc
       cast_i32
       cast_iv
       cast_ulong
       cast_uv
       ck_warner
       ck_warner_d
       ckwarn
       ckwarn_d
       clone_params_del
       clone_params_new
       croak_nocontext
       csighandler
       cx_dump
       cx_dup
       cxinc
       deb
       deb_nocontext
       debop
       debprofdump
       debstack
       debstackptrs
       delimcpy
       despatch_signals
       die_nocontext
       dirp_dup
       do_aspawn
       do_binmode
       do_close
       do_gv_dump
       do_gvgv_dump
       do_hv_dump
       do_join
       do_magic_dump
       do_op_dump
       do_open
       do_open9
       do_openn
       do_pmop_dump
       do_spawn
       do_spawn_nowait
       do_sprintf
       do_sv_dump
       doing_taint
       doref
       dounwind
       dowantarray
       dump_all
       dump_eval
       dump_fds
       dump_form
       dump_indent
       dump_mstats
       dump_packsubs
       dump_sub
       dump_vindent
       filter_add
       filter_del
       filter_read
       foldEQ_latin1
       form_nocontext
       fp_dup
       fprintf_nocontext
       free_global_struct
       free_tmps
       get_context
       get_mstats
       get_op_descs
       get_op_names
       get_ppaddr
       get_vtbl
       gp_dup
       gp_free
       gp_ref
       gv_AVadd
       gv_HVadd
       gv_IOadd
       gv_SVadd
       gv_add_by_type
       gv_autoload4
       gv_autoload_pv
       gv_autoload_pvn
       gv_autoload_sv
       gv_check
       gv_dump
       gv_efullname
       gv_efullname3
       gv_efullname4
       gv_fetchfile
       gv_fetchfile_flags
       gv_fetchpv
       gv_fetchpvn_flags
       gv_fetchsv
       gv_fullname
       gv_fullname3
       gv_fullname4
       gv_handler
       gv_name_set
       he_dup
       hek_dup
       hv_common
       hv_common_key_len
       hv_delayfree_ent
       hv_eiter_p
       hv_eiter_set
       hv_free_ent
       hv_ksplit
       hv_name_set
       hv_placeholders_get
       hv_placeholders_p
       hv_placeholders_set
       hv_riter_p
       hv_riter_set
       init_global_struct
       init_i18nl10n
       init_i18nl14n
       init_stacks
       init_tm
       instr
       is_lvalue_sub
       is_uni_alnum
       is_uni_alnum_lc
       is_uni_alpha
       is_uni_alpha_lc
       is_uni_ascii
       is_uni_ascii_lc
       is_uni_cntrl
       is_uni_cntrl_lc
       is_uni_digit
       is_uni_digit_lc
       is_uni_graph
       is_uni_graph_lc
       is_uni_idfirst
       is_uni_idfirst_lc
       is_uni_lower
       is_uni_lower_lc
       is_uni_print
       is_uni_print_lc
       is_uni_punct
       is_uni_punct_lc
       is_uni_space
       is_uni_space_lc
       is_uni_upper
       is_uni_upper_lc
       is_uni_xdigit
       is_uni_xdigit_lc
       is_utf8_alnum
       is_utf8_alpha
       is_utf8_ascii
       is_utf8_cntrl
       is_utf8_digit
       is_utf8_graph
       is_utf8_idcont
       is_utf8_idfirst
       is_utf8_lower
       is_utf8_mark
       is_utf8_perl_space
       is_utf8_perl_word
       is_utf8_posix_digit
       is_utf8_print
       is_utf8_punct
       is_utf8_space
       is_utf8_upper
       is_utf8_xdigit
       is_utf8_xidcont
       is_utf8_xidfirst
       leave_scope
       load_module_nocontext
       magic_dump
       malloc
       markstack_grow
       mess_nocontext
       mfree
       mg_dup
       mg_size
       mini_mktime
       moreswitches
       mro_get_from_name
       mro_get_private_data
       mro_set_mro
       mro_set_private_data
       my_atof
       my_atof2
       my_bcopy
       my_bzero
       my_chsize
       my_cxt_index
       my_cxt_init
       my_dirfd
       my_exit
       my_failure_exit
       my_fflush_all
       my_fork
       my_htonl
       my_lstat
       my_memcmp
       my_memset
       my_ntohl
       my_pclose
       my_popen
       my_popen_list
       my_setenv
       my_socketpair
       my_stat
       my_strftime
       my_strlcat
       my_strlcpy
       my_swap
       newANONATTRSUB
       newANONHASH
       newANONLIST
       newANONSUB
       newATTRSUB
       newAVREF
       newCVREF
       newFORM
       newGVREF
       newGVgen
       newGVgen_flags
       newHVREF
       newHVhv
       newIO
       newMYSUB
       newPROG
       newRV
       newSUB
       newSVREF
       newSVpvf_nocontext
       new_collate
       new_ctype
       new_numeric
       new_stackinfo
       ninstr
       op_dump
       op_free
       op_null
       op_refcnt_lock
       op_refcnt_unlock
       parser_dup
       perl_alloc_using
       perl_clone_using
       pmop_dump
       pop_scope
       pregcomp
       pregexec
       pregfree
       pregfree2
       printf_nocontext
       ptr_table_clear
       ptr_table_fetch
       ptr_table_free
       ptr_table_new
       ptr_table_split
       ptr_table_store
       push_scope
       re_compile
       re_dup_guts
       re_intuit_start
       re_intuit_string
       realloc
       reentrant_free
       reentrant_init
       reentrant_retry
       reentrant_size
       ref
       reg_named_buff_all
       reg_named_buff_exists
       reg_named_buff_fetch
       reg_named_buff_firstkey
       reg_named_buff_nextkey
       reg_named_buff_scalar
       regclass_swash
       regdump
       regdupe_internal
       regexec_flags
       regfree_internal
       reginitcolors
       regnext
       repeatcpy
       rninstr
       rsignal
       rsignal_state
       runops_debug
       runops_standard
       rvpv_dup
       safesyscalloc
       safesysfree
       safesysmalloc
       safesysrealloc
       save_I16
       save_I32
       save_I8
       save_adelete
       save_aelem
       save_aelem_flags
       save_alloc
       save_aptr
       save_ary
       save_bool
       save_clearsv
       save_delete
       save_destructor
       save_destructor_x
       save_freeop
       save_freepv
       save_freesv
       save_generic_pvref
       save_generic_svref
       save_gp
       save_hash
       save_hdelete
       save_helem
       save_helem_flags
       save_hints
       save_hptr
       save_int
       save_item
       save_iv
       save_list
       save_long
       save_mortalizesv
       save_nogv
       save_op
       save_padsv_and_mortalize
       save_pptr
       save_pushi32ptr
       save_pushptr
       save_pushptrptr
       save_re_context
       save_scalar
       save_set_svflags
       save_shared_pvref
       save_sptr
       save_svref
       save_vptr
       savestack_grow
       savestack_grow_cnt
       scan_num
       scan_vstring
       screaminstr
       seed
       set_context
       set_numeric_local
       set_numeric_radix
       set_numeric_standard
       share_hek
       si_dup
       ss_dup
       stack_grow
       start_subparse
       stashpv_hvname_match
       str_to_version
       sv_2iv
       sv_2pv
       sv_2uv
       sv_catpvf_mg_nocontext
       sv_catpvf_nocontext
       sv_compile_2op
       sv_dump
       sv_dup
       sv_dup_inc
       sv_peek
       sv_pvn_nomg
       sv_setpvf_mg_nocontext
       sv_setpvf_nocontext
       sv_utf8_upgrade_flags_grow
       swash_fetch
       swash_init
       sys_init
       sys_init3
       sys_intern_clear
       sys_intern_dup
       sys_intern_init
       sys_term
       taint_env
       taint_proper
       tmps_grow
       to_uni_fold
       to_uni_lower
       to_uni_lower_lc
       to_uni_title
       to_uni_title_lc
       to_uni_upper
       to_uni_upper_lc
       unlnk
       unsharepvn
       utf16_to_utf8
       utf16_to_utf8_reversed
       uvchr_to_utf8_flags
       uvuni_to_utf8
       vdeb
       vform
       vload_module
       vnewSVpvf
       vwarner
       warn_nocontext
       warner
       warner_nocontext
       whichsig
       whichsig_pv
       whichsig_pvn
       whichsig_sv

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

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

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

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

SEE ALSO
       perlguts, perlxs, perlxstut, perlintern

perl v5.16.3			  2014-03-16			    PERLAPI(1)
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