perlapi - Online in the Cloud

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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. Anything not listed here is
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. Again,
those not listed here are not to be used by extension writers, and can be changed or
removed without notice; same with macros. 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 either ASCII or EBCDIC (See perlebcdic).
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.

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_top_index()". Deprecated, use "av_top_index()" instead.

int AvFILL(AV* av)

av_clear
Frees the all the elements of an array, leaving it empty. The XS equivalent of
"@array = ()". See also "av_undef".

Note that it is possible that the actions of a destructor called directly or
indirectly by freeing an element of the array could cause the reference count of
the array itself to be reduced (e.g. by deleting an entry in the symbol table). So
it is a possibility that the AV could have been freed (or even reallocated) on
return from the call unless you hold a reference to it.

void av_clear(AV *av)

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

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.

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

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

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.

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, SSize_t 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 NULL.

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

bool av_exists(AV *av, SSize_t key)

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

void av_extend(AV *av, SSize_t 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, SSize_t 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 array will be "fill + 1" after av_fill() returns.
If the array was previously shorter, then the additional elements appended are set
to NULL. 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, SSize_t fill)

av_len Same as "av_top_index". Note that, unlike what the name implies, it returns the
highest index in the array, so to get the size of the array you need to use
"av_len(av) + 1". This is unlike "sv_len", which returns what you would expect.

SSize_t 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(SSize_t size, SV **strp)

av_pop Removes one SV from the end of the array, reducing its size by one and returning
the SV (transferring control of one reference count) to the caller. 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
Removes one SV from the start of the array, reducing its size by one and returning
the SV (transferring control of one reference count) to the caller. 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, SSize_t key, SV *val)

av_tindex
Same as "av_top_index()".

int av_tindex(AV* av)

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

The Perl equivalent for this is $#myarray.

(A slightly shorter form is "av_tindex".)

SSize_t av_top_index(AV *av)

av_undef
Undefines the array. The XS equivalent of "undef(@array)".

As well as freeing all the elements of the array (like "av_clear()"), this also
frees the memory used by the av to store its list of scalars.

See "av_clear" for a note about the array possibly being invalid on return.

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, SSize_t 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_top_index(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)

"xsubpp" variables and 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

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_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.

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 specified by the SV.

If neither the "G_METHOD" or "G_METHOD_NAMED" flag is supplied, the SV may be any
of a CV, a GV, a reference to a CV, a reference to a GV or "SvPV(sv)" will be used
as the name of the sub to call.

If the "G_METHOD" flag is supplied, the SV may be a reference to a CV or
"SvPV(sv)" will be used as the name of the method to call.

If the "G_METHOD_NAMED" flag is supplied, "SvPV(sv)" will be used as the name of
the method to call.

Some other values are treated specially for internal use and should not be
depended on.

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 in scalar context 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

toFOLD Converts the specified character to foldcase. If the input is anything but an
ASCII uppercase character, that input character itself is returned. Variant
"toFOLD_A" is equivalent. (There is no equivalent "to_FOLD_L1" for the full
Latin1 range, as the full generality of "toFOLD_uni" is needed there.)

U8 toFOLD(U8 ch)

toFOLD_uni
Converts the Unicode code point "cp" to its foldcase version, and stores that in
UTF-8 in "s", and its length in bytes in "lenp". Note that the buffer pointed to
by "s" needs to be at least "UTF8_MAXBYTES_CASE+1" bytes since the foldcase
version may be longer than the original character.

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

UV toFOLD_uni(UV cp, U8* s, STRLEN* lenp)

toFOLD_utf8
Converts the UTF-8 encoded character at "p" to its foldcase version, and stores
that in UTF-8 in "s", and its length in bytes in "lenp". Note that the buffer
pointed to by "s" needs to be at least "UTF8_MAXBYTES_CASE+1" bytes since the
foldcase version may be longer than the original character.

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

The input character at "p" is assumed to be well-formed.

UV toFOLD_utf8(U8* p, U8* s, STRLEN* lenp)

toLOWER Converts the specified character to lowercase. If the input is anything but an
ASCII uppercase character, that input character itself is returned. Variant
"toLOWER_A" is equivalent.

U8 toLOWER(U8 ch)

toLOWER_L1
Converts the specified Latin1 character to lowercase. The results are undefined
if the input doesn't fit in a byte.

U8 toLOWER_L1(U8 ch)

toLOWER_LC
Converts the specified character to lowercase using the current locale's rules, if
possible; otherwise returns the input character itself.

U8 toLOWER_LC(U8 ch)

toLOWER_uni
Converts the Unicode code point "cp" to its lowercase version, and stores that in
UTF-8 in "s", and its length in bytes in "lenp". Note that the buffer pointed to
by "s" needs to be at least "UTF8_MAXBYTES_CASE+1" bytes since the lowercase
version may be longer than the original character.

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

UV toLOWER_uni(UV cp, U8* s, STRLEN* lenp)

toLOWER_utf8
Converts the UTF-8 encoded character at "p" to its lowercase version, and stores
that in UTF-8 in "s", and its length in bytes in "lenp". Note that the buffer
pointed to by "s" needs to be at least "UTF8_MAXBYTES_CASE+1" bytes since the
lowercase version may be longer than the original character.

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

The input character at "p" is assumed to be well-formed.

UV toLOWER_utf8(U8* p, U8* s, STRLEN* lenp)

toTITLE Converts the specified character to titlecase. If the input is anything but an
ASCII lowercase character, that input character itself is returned. Variant
"toTITLE_A" is equivalent. (There is no "toTITLE_L1" for the full Latin1 range,
as the full generality of "toTITLE_uni" is needed there. Titlecase is not a
concept used in locale handling, so there is no functionality for that.)

U8 toTITLE(U8 ch)

toTITLE_uni
Converts the Unicode code point "cp" to its titlecase version, and stores that in
UTF-8 in "s", and its length in bytes in "lenp". Note that the buffer pointed to
by "s" needs to be at least "UTF8_MAXBYTES_CASE+1" bytes since the titlecase
version may be longer than the original character.

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

UV toTITLE_uni(UV cp, U8* s, STRLEN* lenp)

toTITLE_utf8
Converts the UTF-8 encoded character at "p" to its titlecase version, and stores
that in UTF-8 in "s", and its length in bytes in "lenp". Note that the buffer
pointed to by "s" needs to be at least "UTF8_MAXBYTES_CASE+1" bytes since the
titlecase version may be longer than the original character.

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

The input character at "p" is assumed to be well-formed.

UV toTITLE_utf8(U8* p, U8* s, STRLEN* lenp)

toUPPER Converts the specified character to uppercase. If the input is anything but an
ASCII lowercase character, that input character itself is returned. Variant
"toUPPER_A" is equivalent.

U8 toUPPER(U8 ch)

toUPPER_uni
Converts the Unicode code point "cp" to its uppercase version, and stores that in
UTF-8 in "s", and its length in bytes in "lenp". Note that the buffer pointed to
by "s" needs to be at least "UTF8_MAXBYTES_CASE+1" bytes since the uppercase
version may be longer than the original character.

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

UV toUPPER_uni(UV cp, U8* s, STRLEN* lenp)

toUPPER_utf8
Converts the UTF-8 encoded character at "p" to its uppercase version, and stores
that in UTF-8 in "s", and its length in bytes in "lenp". Note that the buffer
pointed to by "s" needs to be at least "UTF8_MAXBYTES_CASE+1" bytes since the
uppercase version may be longer than the original character.

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

The input character at "p" is assumed to be well-formed.

UV toUPPER_utf8(U8* p, U8* s, STRLEN* lenp)

Character classification

This section is about functions (really macros) that classify characters into types, such
as punctuation versus alphabetic, etc. Most of these are analogous to regular expression
character classes. (See "POSIX Character Classes" in perlrecharclass.) There are several
variants for each class. (Not all macros have all variants; each item below lists the
ones valid for it.) None are affected by "use bytes", and only the ones with "LC" in the
name are affected by the current locale.

The base function, e.g., "isALPHA()", takes an octet (either a "char" or a "U8") as input
and returns a boolean as to whether or not the character represented by that octet is (or
on non-ASCII platforms, corresponds to) an ASCII character in the named class based on
platform, Unicode, and Perl rules. If the input is a number that doesn't fit in an octet,
FALSE is returned.

Variant "isFOO_A" (e.g., "isALPHA_A()") is identical to the base function with no suffix
"_A".

Variant "isFOO_L1" imposes the Latin-1 (or EBCDIC equivlalent) 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, "isWORDCHAR_L1()" will return true when called with the code point 0xDF,
which is a word character in both ASCII and EBCDIC (though it represents different
characters in each).

Variant "isFOO_uni" is like the "isFOO_L1" variant, but accepts any UV code point as
input. If the code point is larger than 255, Unicode rules are used to determine if it is
in the character class. For example, "isWORDCHAR_uni(0x100)" returns TRUE, since 0x100 is
LATIN CAPITAL LETTER A WITH MACRON in Unicode, and is a word character.

Variant "isFOO_utf8" is like "isFOO_uni", but the input is a pointer to a (known to be
well-formed) UTF-8 encoded string ("U8*" or "char*"). The classification of just the
first (possibly multi-byte) character in the string is tested.

Variant "isFOO_LC" is like the "isFOO_A" and "isFOO_L1" variants, but the result is based
on the current locale, which is what "LC" in the name stands for. If Perl can determine
that the current locale is a UTF-8 locale, it uses the published Unicode rules; otherwise,
it uses the C library function that gives the named classification. For example,
"isDIGIT_LC()" when not in a UTF-8 locale returns the result of calling "isdigit()".
FALSE is always returned if the input won't fit into an octet. On some platforms where
the C library function is known to be defective, Perl changes its result to follow the
POSIX standard's rules.

Variant "isFOO_LC_uvchr" is like "isFOO_LC", but is defined on any UV. It returns the
same as "isFOO_LC" for input code points less than 256, and returns the hard-coded, not-
affected-by-locale, Unicode results for larger ones.

Variant "isFOO_LC_utf8" is like "isFOO_LC_uvchr", but the input is a pointer to a (known
to be well-formed) UTF-8 encoded string ("U8*" or "char*"). The classification of just
the first (possibly multi-byte) character in the string is tested.

isALPHA Returns a boolean indicating whether the specified character is an alphabetic
character, analogous to "m/[[:alpha:]]/". See the top of this section for an
explanation of variants "isALPHA_A", "isALPHA_L1", "isALPHA_uni", "isALPHA_utf8",
"isALPHA_LC", "isALPHA_LC_uvchr", and "isALPHA_LC_utf8".

bool isALPHA(char ch)

isALPHANUMERIC
Returns a boolean indicating whether the specified character is a either an
alphabetic character or decimal digit, analogous to "m/[[:alnum:]]/". See the top
of this section for an explanation of variants "isALPHANUMERIC_A",
"isALPHANUMERIC_L1", "isALPHANUMERIC_uni", "isALPHANUMERIC_utf8",
"isALPHANUMERIC_LC", "isALPHANUMERIC_LC_uvchr", and "isALPHANUMERIC_LC_utf8".

bool isALPHANUMERIC(char ch)

isASCII Returns a boolean indicating whether the specified character is one of the 128
characters in the ASCII character set, analogous to "m/[[:ascii:]]/". On non-
ASCII platforms, it returns TRUE iff this character corresponds to an ASCII
character. Variants "isASCII_A()" and "isASCII_L1()" are identical to
"isASCII()". See the top of this section for an explanation of variants
"isASCII_uni", "isASCII_utf8", "isASCII_LC", "isASCII_LC_uvchr", and
"isASCII_LC_utf8". Note, however, that some platforms do not have the C library
routine "isascii()". In these cases, the variants whose names contain "LC" are
the same as the corresponding ones without.

Also note, that because all ASCII characters are UTF-8 invariant (meaning they
have the exact same representation (always a single byte) whether encoded in UTF-8
or not), "isASCII" will give the correct results when called with any byte in any
string encoded or not in UTF-8. And similarly "isASCII_utf8" will work properly
on any string encoded or not in UTF-8.

bool isASCII(char ch)

isBLANK Returns a boolean indicating whether the specified character is a character
considered to be a blank, analogous to "m/[[:blank:]]/". See the top of this
section for an explanation of variants "isBLANK_A", "isBLANK_L1", "isBLANK_uni",
"isBLANK_utf8", "isBLANK_LC", "isBLANK_LC_uvchr", and "isBLANK_LC_utf8". Note,
however, that some platforms do not have the C library routine "isblank()". In
these cases, the variants whose names contain "LC" are the same as the
corresponding ones without.

bool isBLANK(char ch)

isCNTRL Returns a boolean indicating whether the specified character is a control
character, analogous to "m/[[:cntrl:]]/". See the top of this section for an
explanation of variants "isCNTRL_A", "isCNTRL_L1", "isCNTRL_uni", "isCNTRL_utf8",
"isCNTRL_LC", "isCNTRL_LC_uvchr", and "isCNTRL_LC_utf8" On EBCDIC platforms, you
almost always want to use the "isCNTRL_L1" variant.

bool isCNTRL(char ch)

isDIGIT Returns a boolean indicating whether the specified character is a digit, analogous
to "m/[[:digit:]]/". Variants "isDIGIT_A" and "isDIGIT_L1" are identical to
"isDIGIT". See the top of this section for an explanation of variants
"isDIGIT_uni", "isDIGIT_utf8", "isDIGIT_LC", "isDIGIT_LC_uvchr", and
"isDIGIT_LC_utf8".

bool isDIGIT(char ch)

isGRAPH Returns a boolean indicating whether the specified character is a graphic
character, analogous to "m/[[:graph:]]/". See the top of this section for an
explanation of variants "isGRAPH_A", "isGRAPH_L1", "isGRAPH_uni", "isGRAPH_utf8",
"isGRAPH_LC", "isGRAPH_LC_uvchr", and "isGRAPH_LC_utf8".

bool isGRAPH(char ch)

isIDCONT
Returns a boolean indicating whether the specified character can be the second or
succeeding character of an identifier. This is very close to, but not quite the
same as the official Unicode property "XID_Continue". The difference is that this
returns true only if the input character also matches "isWORDCHAR". See the top
of this section for an explanation of variants "isIDCONT_A", "isIDCONT_L1",
"isIDCONT_uni", "isIDCONT_utf8", "isIDCONT_LC", "isIDCONT_LC_uvchr", and
"isIDCONT_LC_utf8".

bool isIDCONT(char ch)

isIDFIRST
Returns a boolean indicating whether the specified character can be the first
character of an identifier. This is very close to, but not quite the same as the
official Unicode property "XID_Start". The difference is that this returns true
only if the input character also matches "isWORDCHAR". See the top of this
section for an explanation of variants "isIDFIRST_A", "isIDFIRST_L1",
"isIDFIRST_uni", "isIDFIRST_utf8", "isIDFIRST_LC", "isIDFIRST_LC_uvchr", and
"isIDFIRST_LC_utf8".

bool isIDFIRST(char ch)

isLOWER Returns a boolean indicating whether the specified character is a lowercase
character, analogous to "m/[[:lower:]]/". See the top of this section for an
explanation of variants "isLOWER_A", "isLOWER_L1", "isLOWER_uni", "isLOWER_utf8",
"isLOWER_LC", "isLOWER_LC_uvchr", and "isLOWER_LC_utf8".

bool isLOWER(char ch)

isOCTAL Returns a boolean indicating whether the specified character is an octal digit,
[0-7]. The only two variants are "isOCTAL_A" and "isOCTAL_L1"; each is identical
to "isOCTAL".

bool isOCTAL(char ch)

isPRINT Returns a boolean indicating whether the specified character is a printable
character, analogous to "m/[[:print:]]/". See the top of this section for an
explanation of variants "isPRINT_A", "isPRINT_L1", "isPRINT_uni", "isPRINT_utf8",
"isPRINT_LC", "isPRINT_LC_uvchr", and "isPRINT_LC_utf8".

bool isPRINT(char ch)

isPSXSPC
(short for Posix Space) Starting in 5.18, this is identical in all its forms to
the corresponding "isSPACE()" macros. The locale forms of this macro are
identical to their corresponding "isSPACE()" forms in all Perl releases. In
releases prior to 5.18, the non-locale forms differ from their "isSPACE()" forms
only in that the "isSPACE()" forms don't match a Vertical Tab, and the
"isPSXSPC()" forms do. Otherwise they are identical. Thus this macro is
analogous to what "m/[[:space:]]/" matches in a regular expression. See the top
of this section for an explanation of variants "isPSXSPC_A", "isPSXSPC_L1",
"isPSXSPC_uni", "isPSXSPC_utf8", "isPSXSPC_LC", "isPSXSPC_LC_uvchr", and
"isPSXSPC_LC_utf8".

bool isPSXSPC(char ch)

isPUNCT Returns a boolean indicating whether the specified character is a punctuation
character, analogous to "m/[[:punct:]]/". Note that the definition of what is
punctuation isn't as straightforward as one might desire. See "POSIX Character
Classes" in perlrecharclass for details. See the top of this section for an
explanation of variants "isPUNCT_A", "isPUNCT_L1", "isPUNCT_uni", "isPUNCT_utf8",
"isPUNCT_LC", "isPUNCT_LC_uvchr", and "isPUNCT_LC_utf8".

bool isPUNCT(char ch)

isSPACE Returns a boolean indicating whether the specified character is a whitespace
character. This is analogous to what "m/\s/" matches in a regular expression.
Starting in Perl 5.18 this also matches what "m/[[:space:]]/" does. Prior to
5.18, only the locale forms of this macro (the ones with "LC" in their names)
matched precisely what "m/[[:space:]]/" does. In those releases, the only
difference, in the non-locale variants, was that "isSPACE()" did not match a
vertical tab. (See "isPSXSPC" for a macro that matches a vertical tab in all
releases.) See the top of this section for an explanation of variants
"isSPACE_A", "isSPACE_L1", "isSPACE_uni", "isSPACE_utf8", "isSPACE_LC",
"isSPACE_LC_uvchr", and "isSPACE_LC_utf8".

bool isSPACE(char ch)

isUPPER Returns a boolean indicating whether the specified character is an uppercase
character, analogous to "m/[[:upper:]]/". See the top of this section for an
explanation of variants "isUPPER_A", "isUPPER_L1", "isUPPER_uni", "isUPPER_utf8",
"isUPPER_LC", "isUPPER_LC_uvchr", and "isUPPER_LC_utf8".

bool isUPPER(char ch)

isWORDCHAR
Returns a boolean indicating whether the specified character is a character that
is a word character, analogous to what "m/\w/" and "m/[[:word:]]/" match in a
regular expression. A word character is an alphabetic character, a decimal digit,
a connecting punctuation character (such as an underscore), or a "mark" character
that attaches to one of those (like some sort of accent). "isALNUM()" is a
synonym provided for backward compatibility, even though a word character includes
more than the standard C language meaning of alphanumeric. See the top of this
section for an explanation of variants "isWORDCHAR_A", "isWORDCHAR_L1",
"isWORDCHAR_uni", and "isWORDCHAR_utf8". "isWORDCHAR_LC", "isWORDCHAR_LC_uvchr",
and "isWORDCHAR_LC_utf8" are also as described there, but additionally include the
platform's native underscore.

bool isWORDCHAR(char ch)

isXDIGIT
Returns a boolean indicating whether the specified character is a hexadecimal
digit. In the ASCII range these are "[0-9A-Fa-f]". Variants "isXDIGIT_A()" and
"isXDIGIT_L1()" are identical to "isXDIGIT()". See the top of this section for an
explanation of variants "isXDIGIT_uni", "isXDIGIT_utf8", "isXDIGIT_LC",
"isXDIGIT_LC_uvchr", and "isXDIGIT_LC_utf8".

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

Temporarily disable an entry in this BHK structure, by clearing the appropriate
flag. which is a preprocessor token indicating which entry to disable.

void BhkDISABLE(BHK *hk, which)

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

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.

void BhkENABLE(BHK *hk, which)

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

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.

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

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

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 must be explicitly called as Perl_blockhook_register with an
aTHX_ parameter.

void Perl_blockhook_register(pTHX_ BHK *hk)

COP Hint Hashes

cophh_2hv
NOTE: this function is experimental and may change or be removed without notice.

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.

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

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

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

COPHH * cophh_copy(COPHH *cophh)

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

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

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

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

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.

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

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

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

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

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

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

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

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

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

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

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

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.

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

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

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

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

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

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

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

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

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

void cophh_free(COPHH *cophh)

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

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

COPHH * cophh_new_empty()

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

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

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

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

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.

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

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

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

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

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

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

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 macro should be considered
internal to OP_NAME and the other access macros: use them instead. This macro
does call a function. Prior to 5.19.6, this was implemented as a function.

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. This macro evaluates its arguments more than once. If you
are using "Perl_custom_op_xop" to retreive a "XOP *" from a "OP *", use the more
efficient "XopENTRYCUSTOM" instead.

XopENTRY(XOP *xop, which)

XopENTRYCUSTOM
Exactly like "XopENTRY(XopENTRY(Perl_custom_op_xop(aTHX_ o), which)" but more
efficient. The which parameter is identical to "XopENTRY".

XopENTRYCUSTOM(const OP *o, 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. This macro evaluates its argument more than once.

void XopENTRY_set(XOP *xop, which, value)

XopFLAGS
Return the XOP's flags.

U32 XopFLAGS(XOP *xop)

CV Manipulation Functions

This section documents functions to manipulate CVs which are code-values, or subroutines.
For more information, see perlguts.

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
)

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)

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. (This 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)

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)

Debugging Utilities

dump_all
Dumps the entire optree of the current program starting at "PL_main_root" to
"STDERR". Also dumps the optrees for all visible subroutines in "PL_defstash".

void dump_all()

dump_packsubs
Dumps the optrees for all visible subroutines in "stash".

void dump_packsubs(const HV* stash)

op_dump Dumps the optree starting at OP "o" to "STDERR".

void op_dump(const OP *o)

sv_dump Dumps the contents of an SV to the "STDERR" filehandle.

For an example of its output, see Devel::Peek.

void sv_dump(SV* sv)

Display and Dump functions

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. The number of bytes escaped will be
returned in the STRLEN *escaped parameter if it is not null. When the dsv
parameter is null no escaping actually occurs, but the number of bytes that would
be escaped were it not null will be calculated.

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 UTF-8 if
PERL_PV_ESCAPE_UNI_DETECT is set then the input string is scanned using
"is_utf8_string()" to determine if it is UTF-8.

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 non-ASCII chars
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)

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_name Returns an SV containing the name of the CV, mainly for use in error reporting.
The CV may actually be a GV instead, in which case the returned SV holds the GV's
name. Anything other than a GV or CV is treated as a string already holding the
sub name, but this could change in the future.

An SV may be passed as a second argument. If so, the name will be assigned to it
and it will be returned. Otherwise the returned SV will be a new mortal.

If the flags include CV_NAME_NOTQUAL, then the package name will not be included.
If the first argument is neither a CV nor a GV, this flag is ignored (subject to
change).

SV * cv_name(CV *cv, SV *sv, U32 flags)

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
DEPRECATED! It is planned to remove this function from a future release of Perl.
Do not use it for new code; remove it from existing code.

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()

intro_my
"Introduce" "my" variables to visible status. This is called during parsing at
the end of each statement to make lexical variables visible to subsequent
statements.

U32 intro_my()

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, ...)

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

Creates a new pad name list. "max" is the highest index for which space is
allocated.

PADNAMELIST * newPADNAMELIST(size_t max)

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

Constructs and returns a new pad name. Only use this function for names that
refer to outer lexicals. (See also "newPADNAMEpvn".) outer is the outer pad name
that this one mirrors. The returned pad name has the PADNAMEt_OUTER flag already
set.

PADNAME * newPADNAMEouter(PADNAME *outer)

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

Constructs and returns a new pad name. s must be a UTF8 string. Do not use this
for pad names that point to outer lexicals. See "newPADNAMEouter".

PADNAME * newPADNAMEpvn(const char *s, STRLEN len)

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

int nothreadhook()

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

Fetches the pad name from the given index.

PADNAME * padnamelist_fetch(PADNAMELIST *pnl,
SSize_t key)

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

Stores the pad name (which may be null) at the given index, freeing any existing
pad name in that slot.

PADNAME ** padnamelist_store(PADNAMELIST *pnl,
SSize_t key, PADNAME *val)

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.

One reference count is stolen, so you may need to do "SvREFCNT_inc(func)".

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

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
SVf_READONLY constant shared between recursion levels

"SVf_READONLY" has been supported here only since perl 5.20. To work with earlier
versions as well, use "SVf_READONLY|SVs_PADTMP". "SVf_READONLY" does not cause
the SV in the pad slot to be marked read-only, but simply tells "pad_alloc" that
it will be made read-only (by the caller), or at least should be treated as such.

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_alloc(I32 optype, U32 tmptype)

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

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

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)

Exception Handling (simple) 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.

Global Variables

These variables are global to an entire process. They are shared between all interpreters
and all threads in a process.

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

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".

GV Functions

A GV is a structure which corresponds to to a Perl typeglob, ie *foo. It is a structure
that holds a pointer to a scalar, an array, a hash etc, corresponding to $foo, @foo, %foo.

GVs are usually found as values in stashes (symbol table hashes) where Perl stores its
global variables.

GvAV Return the AV from the GV.

AV* GvAV(GV* gv)

GvCV Return the CV from the GV.

CV* GvCV(GV* gv)

GvHV Return the HV from the GV.

HV* GvHV(GV* gv)

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 as a side effect to do
this.

These functions have the same side-effects as "gv_fetchmeth" with "level==0". The
warning against passing the GV returned by "gv_fetchmeth" to "call_sv" applies
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.

The only significant values for "flags" are GV_SUPER and SVf_UTF8.

GV_SUPER indicates that we want to look up the method in the superclasses of the
"stash".

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.

Flags may be one of:

GV_ADD
SVf_UTF8
GV_NOADD_NOINIT
GV_NOINIT
GV_NOEXPAND
GV_ADDMG

The most important of which are probably GV_ADD and SVf_UTF8.

Note, use of "gv_stashsv" instead of "gv_stashpvn" where possible is strongly
recommended for performance reasons.

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".

Note this interface is strongly preferred over "gv_stashpvn" for performance
reasons.

HV* gv_stashsv(SV* sv, I32 flags)

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)

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

A HV structure represents a Perl hash. It consists mainly of an array of pointers, each
of which points to a linked list of HE structures. The array is indexed by the hash
function of the key, so each linked list represents all the hash entries with the same
hash value. Each HE contains a pointer to the actual value, plus a pointer to a HEK
structure which holds the key and hash value.

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

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

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

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

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

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".

U32 HeUTF8(HE* he)

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

SV *foo= HeVAL(hv);
HeVAL(hv)= sv;

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".

See "av_clear" for a note about the hash possibly being invalid on return.

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. This means that if there is no value in the hash associated with
the given key, then one is created and a pointer to it is returned. The "SV*" it
points to can be assigned to. But always 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 always stored in the HV structure, which created an
overhead on every hash (and pretty much every object) for something that was
rarely used. Now we calculate it on demand the first time that it is needed, and
cache it if that calculation is going to be costly to repeat. The cached value is
updated by insertions and deletions, but (currently) discarded if the hash is
split.

STRLEN hv_fill(HV *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
NOTE: this function is experimental and may change or be removed without notice.

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.

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.

See "av_clear" for a note about the hash possibly being invalid on return.

void hv_undef(HV *hv)

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

HV* newHV()

Hook manipulation

These functions provide convenient and thread-safe means of manipulating hook variables.

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.

The function should be defined like this:

static OP *new_checker(pTHX_ OP *op) { ... }

It is intended to be called in this manner:

new_checker(aTHX_ op)

old_checker_p should be defined like this:

static Perl_check_t 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

This is the lower layer of the Perl parser, managing characters and tokens.

lex_bufutf8
NOTE: this function is experimental and may change or be removed without notice.

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.

bool lex_bufutf8()

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

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.

void lex_discard_to(char *ptr)

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

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.

char * lex_grow_linestr(STRLEN len)

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

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.

bool lex_next_chunk(U32 flags)

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

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.

I32 lex_peek_unichar(U32 flags)

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

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.

void lex_read_space(U32 flags)

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

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".

void lex_read_to(char *ptr)

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

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.

I32 lex_read_unichar(U32 flags)

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

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.

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

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

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.

void lex_stuff_pv(const char *pv, U32 flags)

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

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.

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

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

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

void lex_stuff_pvs(const char *pv, U32 flags)

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

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.

void lex_stuff_sv(SV *sv, U32 flags)

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

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".

void lex_unstuff(char *ptr)

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

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.

OP * parse_arithexpr(U32 flags)

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

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.

OP * parse_barestmt(U32 flags)

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

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.

OP * parse_block(U32 flags)

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

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.

OP * parse_fullexpr(U32 flags)

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

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.

OP * parse_fullstmt(U32 flags)

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

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.

SV * parse_label(U32 flags)

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

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.

OP * parse_listexpr(U32 flags)

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

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.

OP * parse_stmtseq(U32 flags)

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

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.

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

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.

PL_parser->bufptr
NOTE: this function is experimental and may change or be removed without notice.

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".

PL_parser->linestart
NOTE: this function is experimental and may change or be removed without notice.

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.

PL_parser->linestr
NOTE: this function is experimental and may change or be removed without notice.

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.

Locale-related functions and macros

DECLARATION_FOR_LC_NUMERIC_MANIPULATION
This macro should be used as a statement. It declares a private variable (whose
name begins with an underscore) that is needed by the other macros in this
section. Failing to include this correctly should lead to a syntax error. For
compatibility with C89 C compilers it should be placed in a block before any
executable statements.

void DECLARATION_FOR_LC_NUMERIC_MANIPULATION

RESTORE_LC_NUMERIC
This is used in conjunction with one of the macros
"STORE_LC_NUMERIC_SET_TO_NEEDED" and "STORE_LC_NUMERIC_FORCE_TO_UNDERLYING"

to properly restore the "LC_NUMERIC" state.

A call to "DECLARATION_FOR_LC_NUMERIC_MANIPULATION" must have been made to declare
at compile time a private variable used by this macro and the two "STORE" ones.
This macro should be called as a single statement, not an expression, but with an
empty argument list, like this:

{
DECLARATION_FOR_LC_NUMERIC_MANIPULATION;
...
RESTORE_LC_NUMERIC();
...
}

void RESTORE_LC_NUMERIC()

STORE_LC_NUMERIC_FORCE_TO_UNDERLYING
This is used by XS code that that is "LC_NUMERIC" locale-aware to force the locale
for category "LC_NUMERIC" to be what perl thinks is the current underlying locale.
(The perl interpreter could be wrong about what the underlying locale actually is
if some C or XS code has called the C library function setlocale(3) behind its
back; calling "sync_locale" before calling this macro will update perl's records.)

A call to "DECLARATION_FOR_LC_NUMERIC_MANIPULATION" must have been made to declare
at compile time a private variable used by this macro. This macro should be
called as a single statement, not an expression, but with an empty argument list,
like this:

{
DECLARATION_FOR_LC_NUMERIC_MANIPULATION;
...
STORE_LC_NUMERIC_FORCE_TO_UNDERLYING();
...
RESTORE_LC_NUMERIC();
...
}

The private variable is used to save the current locale state, so that the
requisite matching call to "RESTORE_LC_NUMERIC" can restore it.

void STORE_LC_NUMERIC_FORCE_TO_UNDERLYING()

STORE_LC_NUMERIC_SET_TO_NEEDED
This is used to help wrap XS or C code that that is "LC_NUMERIC" locale-aware.
This locale category is generally kept set to the C locale by Perl for backwards
compatibility, and because most XS code that reads floating point values can cope
only with the decimal radix character being a dot.

This macro makes sure the current "LC_NUMERIC" state is set properly, to be aware
of locale if the call to the XS or C code from the Perl program is from within the
scope of a "use locale"; or to ignore locale if the call is instead from outside
such scope.

This macro is the start of wrapping the C or XS code; the wrap ending is done by
calling the "RESTORE_LC_NUMERIC" macro after the operation. Otherwise the state
can be changed that will adversely affect other XS code.

A call to "DECLARATION_FOR_LC_NUMERIC_MANIPULATION" must have been made to declare
at compile time a private variable used by this macro. This macro should be
called as a single statement, not an expression, but with an empty argument list,
like this:

{
DECLARATION_FOR_LC_NUMERIC_MANIPULATION;
...
STORE_LC_NUMERIC_SET_TO_NEEDED();
...
RESTORE_LC_NUMERIC();
...
}

void STORE_LC_NUMERIC_SET_TO_NEEDED()

sync_locale
Changing the program's locale should be avoided by XS code. Nevertheless, certain
non-Perl libraries called from XS, such as "Gtk" do so. When this happens, Perl
needs to be told that the locale has changed. Use this function to do so, before
returning to Perl.

void sync_locale()

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. The type of SV must be >=
SVt_PVMG. See "sv_magic".

int mg_get(SV* sv)

mg_length
DEPRECATED! It is planned to remove this function from a future release of Perl.
Do not use it for new code; remove it from existing code.

Reports on the SV's length in bytes, calling length magic if available, but does
not set the UTF8 flag on the sv. It will fall back to 'get' magic if there is no
'length' magic, but with no indication as to whether it called 'get' magic. It
assumes the sv is a PVMG or higher. Use sv_len() instead.

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. For example, this will call
"FETCH" on a tied variable. 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 is necessary after
modifying a scalar, in case it is a magical variable like $| or a tied variable
(it calls "STORE"). 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* dsv, 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. Does not handle 'set' magic on the destination SV.

void SvSetSV(SV* dsv, 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.

Memory obtained by this should ONLY be freed with "Safefree".

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".

Memory obtained by this should ONLY be freed with "Safefree".

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".

Memory obtained by this should ONLY be freed with "Safefree".

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.

Memory obtained by this should ONLY be freed with "Safefree".

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

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

Memory obtained by this should ONLY be freed with "Safefree".

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

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

This should ONLY be used on memory obtained using "Newx" and friends.

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()", which
means it may not contain embedded "NUL" characters and must have a trailing "NUL".
The memory allocated for the new string can be freed with the "Safefree()"
function.

On some platforms, Windows for example, all allocated memory owned by a thread is
deallocated when that thread ends. So if you need that not to happen, you need to
use the shared memory functions, such as "savesharedpv".

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.

On some platforms, Windows for example, all allocated memory owned by a thread is
deallocated when that thread ends. So if you need that not to happen, you need to
use the shared memory functions, such as "savesharedpvn".

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

savepvs Like "savepvn", but takes a literal "NUL"-terminated 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()"

On some platforms, Windows for example, all allocated memory owned by a thread is
deallocated when that thread ends. So if you need that not to happen, you need to
use the shared memory functions, such as "savesharedsvpv".

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

dump_c_backtrace
Dumps the C backtrace to the given fp.

Returns true if a backtrace could be retrieved, false if not.

bool dump_c_backtrace(PerlIO* fp, int max_depth,
int skip)

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 "big" and "bigend". 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)

get_c_backtrace_dump
Returns a SV a dump of |depth| frames of the call stack, skipping the |skip|
innermost ones. depth of 20 is usually enough.

The appended output looks like:

... 1 10e004812:0082 Perl_croak util.c:1716 /usr/bin/perl 2
10df8d6d2:1d72 perl_parse perl.c:3975 /usr/bin/perl ...

The fields are tab-separated. The first column is the depth (zero being the
innermost non-skipped frame). In the hex:offset, the hex is where the program
counter was in S_parse_body, and the :offset (might be missing) tells how much
inside the S_parse_body the program counter was.

The util.c:1716 is the source code file and line number.

The /usr/bin/perl is obvious (hopefully).

Unknowns are "-". Unknowns can happen unfortunately quite easily: if the platform
doesn't support retrieving the information; if the binary is missing the debug
information; if the optimizer has transformed the code by for example inlining.

SV* get_c_backtrace_dump(int max_depth, int skip)

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)

is_safe_syscall
Test that the given "pv" doesn't contain any internal "NUL" characters. If it
does, set "errno" to ENOENT, optionally warn, and return FALSE.

Return TRUE if the name is safe.

Used by the IS_SAFE_SYSCALL() macro.

bool is_safe_syscall(const char *pv, STRLEN len,
const char *what,
const char *op_name)

memEQ Test two buffers (which may contain embedded "NUL" characters, to see if they are
equal. The "len" parameter indicates the number of bytes to compare. Returns
zero if equal, or non-zero if non-equal.

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

memNE Test two buffers (which may contain embedded "NUL" characters, to see if they are
not equal. The "len" parameter indicates the number of bytes to compare. Returns
zero if non-equal, or non-zero if equal.

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

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_strlcat
The C library "strlcat" if available, or a Perl implementation of it. This
operates on C "NUL"-terminated strings.

"my_strlcat()" appends string "src" to the end of "dst". It will append at most
"size - strlen(dst) - 1" characters. It will then "NUL"-terminate, unless "size"
is 0 or the original "dst" string was longer than "size" (in practice this should
not happen as it means that either "size" is incorrect or that "dst" is not a
proper "NUL"-terminated string).

Note that "size" is the full size of the destination buffer and the result is
guaranteed to be "NUL"-terminated if there is room. Note that room for the "NUL"
should be included in "size".

Size_t my_strlcat(char *dst, const char *src,
Size_t size)

my_strlcpy
The C library "strlcpy" if available, or a Perl implementation of it. This
operates on C "NUL"-terminated strings.

"my_strlcpy()" copies up to "size - 1" characters from the string "src" to "dst",
"NUL"-terminating the result if "size" is not 0.

Size_t my_strlcpy(char *dst, const char *src,
Size_t size)

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)

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()

quadmath_format_needed
quadmath_format_needed() returns true if the format string seems to contain at
least one non-Q-prefixed %[efgaEFGA] format specifier, or returns false otherwise.

The format specifier detection is not complete printf-syntax detection, but it
should catch most common cases.

If true is returned, those arguments should in theory be processed with
quadmath_snprintf(), but in case there is more than one such format specifier (see
"quadmath_format_single"), and if there is anything else beyond that one (even
just a single byte), they cannot be processed because quadmath_snprintf() is very
strict, accepting only one format spec, and nothing else. In this case, the code
should probably fail.

bool quadmath_format_needed(const char* format)

quadmath_format_single
quadmath_snprintf() is very strict about its format string and will fail,
returning -1, if the format is invalid. It acccepts exactly one format spec.

quadmath_format_single() checks that the intended single spec looks sane: begins
with "%", has only one "%", ends with "[efgaEFGA]", and has "Q" before it. This
is not a full "printf syntax check", just the basics.

Returns the format if it is valid, NULL if not.

quadmath_format_single() can and will actually patch in the missing "Q", if
necessary. In this case it will return the modified copy of the format, which the
caller will need to free.

See also "quadmath_format_needed".

const char* quadmath_format_single(const char* format)

READ_XDIGIT
Returns the value of an ASCII-range hex digit and advances the string pointer.
Behaviour is only well defined when isXDIGIT(*str) is true.

U8 READ_XDIGIT(char str*)

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)

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)

MRO Functions

These functions are related to the method resolution order of perl classes

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_p 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_infnan
Helper for grok_number(), accepts various ways of spelling "infinity" or "not a
number", and returns one of the following flag combinations:

IS_NUMBER_INFINITE
IS_NUMBER_NAN
IS_NUMBER_INFINITE | IS_NUMBER_NEG
IS_NUMBER_NAN | IS_NUMBER_NEG
0

possibly |-ed with IS_NUMBER_TRAILING.

If an infinity or a not-a-number is recognized, the *sp will point to one byte
past the end of the recognized string. If the recognition fails, zero is
returned, and the *sp will not move.

int grok_infnan(const char** sp, const char *send)

grok_number
Identical to grok_number_flags() with flags set to zero.

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

grok_number_flags
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 in a 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.

"flags" allows only "PERL_SCAN_TRAILING", which allows for trailing non-numeric
text on an otherwise successful grok, setting "IS_NUMBER_TRAILING" on the result.

int grok_number_flags(const char *pv, STRLEN len,
UV *valuep, U32 flags)

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)

isinfnan
Perl_isinfnan() is utility function that returns true if the NV argument is either
an infinity or a NaN, false otherwise. To test in more detail, use Perl_isinf()
and Perl_isnan().

This is also the logical inverse of Perl_isfinite().

bool isinfnan(NV nv)

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

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. The main use of this function is catching -0.0.

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().

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)

Obsolete backwards compatibility functions

Some of these are also deprecated. You can exclude these from your compiled Perl by
adding this option to Configure: "-Accflags='-DNO_MATHOMS'"

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)

is_utf8_char
DEPRECATED! It is planned to remove this function from a future release of Perl.
Do not use it for new code; remove it from existing code.

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 "isUTF8_CHAR" instead.

STRLEN is_utf8_char(const U8 *s)

is_utf8_char_buf
This is identical to the macro "isUTF8_CHAR".

STRLEN is_utf8_char_buf(const U8 *buf,
const U8 *buf_end)

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)

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)

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)

utf8_to_uvchr
DEPRECATED! It is planned to remove this function from a future release of Perl.
Do not use it for new code; remove it from existing code.

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_uvchr" for details on when the
REPLACEMENT CHARACTER is returned.

UV utf8_to_uvchr(const U8 *s, STRLEN *retlen)

utf8_to_uvuni
DEPRECATED! It is planned to remove this function from a future release of Perl.
Do not use it for new code; remove it from existing code.

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.

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 one reason
why this function is deprecated. The other is that only in extremely limited
circumstances should the Unicode versus native code point be of any interest to
you. See "utf8_to_uvuni_buf" for alternatives.

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_uvchr" for details on
when the REPLACEMENT CHARACTER is returned.

UV utf8_to_uvuni(const U8 *s, 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)

newDEFSVOP
Constructs and returns an op to access $_, either as a lexical variable (if
declared as "my $_") in the current scope, or the global $_.

OP * newDEFSVOP()

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. If it is 0, the global $_
will be used.

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.

For most list operators, the check function expects all the kid ops to be present
already, so calling "newLISTOP(OP_JOIN, ...)" (e.g.) is not appropriate. What you
want to do in that case is create an op of type OP_LIST, append more children to
it, and then call "op_convert_list". See "op_convert_list" for more information.

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 becomes 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)

newMETHOP
Constructs, checks, and returns an op of method type with a method name evaluated
at runtime. 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.
dynamic_meth supplies an op which evaluates method name; it is consumed by this
function and become part of the constructed op tree. Supported optypes:
OP_METHOD.

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

newMETHOP_named
Constructs, checks, and returns an op of method type with a constant method name.
type is the opcode. flags gives the eight bits of "op_flags", and, shifted up
eight bits, the eight bits of "op_private". const_meth supplies a constant method
name; it must be a shared COW string. Supported optypes: OP_METHOD_NAMED.

OP * newMETHOP_named(I32 type, I32 flags,
SV *const_meth)

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)

newUNOP_AUX
Similar to "newUNOP", but creates an UNOP_AUX struct instead, with op_aux
initialised to aux

OP* newUNOP_AUX(I32 type, I32 flags, OP* first,
UNOP_AUX_item *aux)

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

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

Available only under threaded builds, this function allocates an entry in
"PL_stashpad" for the stash passed to it.

PADOFFSET alloccopstash(HV *hv)

block_end
Handles compile-time scope exit. floor is the savestack index returned by
"block_start", and seq is the body of the block. Returns the block, possibly
modified.

OP * block_end(I32 floor, OP *seq)

block_start
Handles compile-time scope entry. Arranges for hints to be restored on block exit
and also handles pad sequence numbers to make lexical variables scope right.
Returns a savestack index for use with "block_end".

int block_start(int full)

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
The original form of "cv_set_call_checker_flags", which passes it the
"CALL_CHECKER_REQUIRE_GV" flag for backward-compatibility.

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

cv_set_call_checker_flags
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 should be defined like this:

STATIC OP * ckfun(pTHX_ OP *op, GV *namegv, SV *ckobj)

It 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 supplies 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.

namegv may not actually be a GV. For efficiency, perl may pass a CV or other SV
instead. Whatever is passed can be used as the first argument to "cv_name". You
can force perl to pass a GV by including "CALL_CHECKER_REQUIRE_GV" in the flags.

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

void cv_set_call_checker_flags(
CV *cv, Perl_call_checker ckfun, SV *ckobj,
U32 flags
)

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.

The newly created subroutine takes ownership of a reference to the passed in SV.

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.

OpHAS_SIBLING
Returns true if o has a sibling

bool OpHAS_SIBLING(OP *o)

OpLASTSIB_set
Marks o as having no further siblings. On "PERL_OP_PARENT" builds, marks o as
having the specified parent. See also "OpMORESIB_set" and "OpMAYBESIB_set". For a
higher-level interface, see "op_sibling_splice".

void OpLASTSIB_set(OP *o, OP *parent)

OpMAYBESIB_set
Conditionally does "OpMORESIB_set" or "OpLASTSIB_set" depending on whether sib is
non-null. For a higher-level interface, see "op_sibling_splice".

void OpMAYBESIB_set(OP *o, OP *sib, OP *parent)

OpMORESIB_set
Sets the sibling of o to the non-zero value sib. See also "OpLASTSIB_set" and
"OpMAYBESIB_set". For a higher-level interface, see "op_sibling_splice".

void OpMORESIB_set(OP *o, OP *sib)

OpSIBLING
Returns the sibling of o, or NULL if there is no sibling

OP* OpSIBLING(OP *o)

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_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)

op_convert_list
Converts o into a list op if it is not one already, and then converts it into the
specified type, calling its check function, allocating a target if it needs one,
and folding constants.

A list-type op is usually constructed one kid at a time via "newLISTOP",
"op_prepend_elem" and "op_append_elem". Then finally it is passed to
"op_convert_list" to make it the right type.

OP * op_convert_list(I32 type, I32 flags, OP *o)

OP_DESC Return a short description of the provided OP.

const char * OP_DESC(OP *o)

op_free Free an op. Only use this when an op is no longer linked to from any optree.

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

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.

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_null Neutralizes an op when it is no longer needed, but is still linked to from other
ops.

void op_null(OP *o)

op_parent
Returns the parent OP of o, if it has a parent. Returns NULL otherwise. This
function is only available on perls built with "-DPERL_OP_PARENT".

OP* op_parent(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
NOTE: this function is experimental and may change or be removed without notice.

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.

OP * op_scope(OP *o)

op_sibling_splice
A general function for editing the structure of an existing chain of op_sibling
nodes. By analogy with the perl-level splice() function, allows you to delete
zero or more sequential nodes, replacing them with zero or more different nodes.
Performs the necessary op_first/op_last housekeeping on the parent node and
op_sibling manipulation on the children. The last deleted node will be marked as
as the last node by updating the op_sibling/op_sibparent or op_moresib field as
appropriate.

Note that op_next is not manipulated, and nodes are not freed; that is the
responsibility of the caller. It also won't create a new list op for an empty
list etc; use higher-level functions like op_append_elem() for that.

parent is the parent node of the sibling chain. It may passed as NULL if the
splicing doesn't affect the first or last op in the chain.

start is the node preceding the first node to be spliced. Node(s) following it
will be deleted, and ops will be inserted after it. If it is NULL, the first node
onwards is deleted, and nodes are inserted at the beginning.

del_count is the number of nodes to delete. If zero, no nodes are deleted. If -1
or greater than or equal to the number of remaining kids, all remaining kids are
deleted.

insert is the first of a chain of nodes to be inserted in place of the nodes. If
NULL, no nodes are inserted.

The head of the chain of deleted ops is returned, or NULL if no ops were deleted.

For example:

action before after returns
------ ----- ----- -------

P P
splice(P, A, 2, X-Y-Z) | | B-C
A-B-C-D A-X-Y-Z-D

P P
splice(P, NULL, 1, X-Y) | | A
A-B-C-D X-Y-B-C-D

P P
splice(P, NULL, 3, NULL) | | A-B-C
A-B-C-D D

P P
splice(P, B, 0, X-Y) | | NULL
A-B-C-D A-B-X-Y-C-D

For lower-level direct manipulation of "op_sibparent" and "op_moresib", see
"OpMORESIB_set", "OpLASTSIB_set", "OpMAYBESIB_set".

OP* op_sibling_splice(OP *parent, OP *start,
int del_count, OP* insert)

OP_TYPE_IS
Returns true if the given OP is not a NULL pointer and if it is of the given type.

The negation of this macro, "OP_TYPE_ISNT" is also available as well as
"OP_TYPE_IS_NN" and "OP_TYPE_ISNT_NN" which elide the NULL pointer check.

bool OP_TYPE_IS(OP *o, Optype type)

OP_TYPE_IS_OR_WAS
Returns true if the given OP is not a NULL pointer and if it is of the given type
or used to be before being replaced by an OP of type OP_NULL.

The negation of this macro, "OP_TYPE_ISNT_AND_WASNT" is also available as well as
"OP_TYPE_IS_OR_WAS_NN" and "OP_TYPE_ISNT_AND_WASNT_NN" which elide the NULL
pointer check.

bool OP_TYPE_IS_OR_WAS(OP *o, Optype type)

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)

Pack and Unpack

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 the unpack() Perl function.

Using the template pat..patend, this function unpacks the string s..strend into a
number of mortal SVs, which it pushes onto the perl argument (@_) stack (so you
will need to issue a "PUTBACK" before and "SPAGAIN" after the call to this
function). It returns the number of pushed elements.

The strend and patend pointers should point to the byte following the last
character of each string.

Although this function returns its values on the perl argument stack, it doesn't
take any parameters from that stack (and thus in particular there's no need to do
a PUSHMARK before calling it, unlike "call_pv" for example).

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

Pad Data Structures

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

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

For these purposes "formats" 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 do not have a CvPADLIST. dXSTARG fetches values from PL_curpad, but that is
really the callers pad (a slot of which is allocated by every entersub). Do not
get or set CvPADLIST if a CV is an XSUB (as determined by "CvISXSUB()"), CvPADLIST
slot is reused for a different internal purpose in XSUBs.

The PADLIST has a C array where pads are stored.

The 0th entry of the PADLIST is a PADNAMELIST which represents the "names" or
rather the "static type information" for lexicals. The individual elements of a
PADNAMELIST are PADNAMEs. Future refactorings might stop the PADNAMELIST from
being stored in the PADLIST's array, so don't rely on it. See "PadlistNAMES".

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

Iterating over the PADNAMELIST iterates over all possible pad items. Pad slots
for targets (SVs_PADTMP) and GVs end up having &PL_padname_undef "names", while
slots for constants have &PL_padname_const "names" (see pad_alloc()). That
&PL_padname_undef and &PL_padname_const are used is an implementation detail
subject to change. To test for them, use "!PadnamePV(name)" and "PadnamePV(name)
&& !PadnameLEN(name)", respectively.

Only my/our variable 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"" the
way 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 pad names in the PADNAMELIST have their PV holding the name of the variable.
The COP_SEQ_RANGE_LOW and _HIGH fields form a range (low+1..high inclusive) of
cop_seq numbers for which the name is valid. 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 PadnameTYPE points at the type stash. For "our" lexicals,
PadnameOURSTASH points at the stash of the associated global (so that duplicate
"our" declarations in the same package can be detected). PadnameGEN is sometimes
used to store the generation number during compilation.

If PadnameOUTER is set on the pad name, then that slot in the frame AV is a
REFCNT'ed reference to a lexical from "outside". Such entries are sometimes
referred to as 'fake'. In this case, the name does not use 'low' and 'high' to
store a cop_seq range, since it is in scope throughout. Instead 'high' 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, 'low'
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 the PAD is a CV representing a
possible closure.

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', but this
internal state is stored in a separate pad entry.

PADLIST * CvPADLIST(CV *cv)

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

The C array of pad entries.

SV ** PadARRAY(PAD pad)

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

The C array of a padlist, containing the pads. Only subscript it with numbers >=
1, as the 0th entry is not guaranteed to remain usable.

PAD ** PadlistARRAY(PADLIST padlist)

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

The index of the last allocated space in the padlist. Note that the last pad may
be in an earlier slot. Any entries following it will be NULL in that case.

SSize_t PadlistMAX(PADLIST padlist)

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

The names associated with pad entries.

PADNAMELIST * PadlistNAMES(PADLIST padlist)

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

The C array of pad names.

PADNAME ** PadlistNAMESARRAY(PADLIST padlist)

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

The index of the last pad name.

SSize_t PadlistNAMESMAX(PADLIST padlist)

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

The reference count of the padlist. Currently this is always 1.

U32 PadlistREFCNT(PADLIST padlist)

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

The index of the last pad entry.

SSize_t PadMAX(PAD pad)

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

The length of the name.

STRLEN PadnameLEN(PADNAME pn)

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

The C array of pad names.

PADNAME ** PadnamelistARRAY(PADNAMELIST pnl)

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

The index of the last pad name.

SSize_t PadnamelistMAX(PADNAMELIST pnl)

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

The reference count of the pad name list.

SSize_t PadnamelistREFCNT(PADNAMELIST pnl)

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

Lowers the reference count of the pad name list.

void PadnamelistREFCNT_dec(PADNAMELIST pnl)

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

The name stored in the pad name struct. This returns NULL for a target slot.

char * PadnamePV(PADNAME pn)

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

The reference count of the pad name.

SSize_t PadnameREFCNT(PADNAME pn)

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

Lowers the reference count of the pad name.

void PadnameREFCNT_dec(PADNAME pn)

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

Returns the pad name as a mortal SV.

SV * PadnameSV(PADNAME pn)

PadnameUTF8
NOTE: this function is experimental and may change or be removed without notice.

Whether PadnamePV is in UTF8. Currently, this is always true.

bool PadnameUTF8(PADNAME pn)

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

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.

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

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

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

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

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)

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, SSize_t 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.

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. Identical to POPp. There are two names for
historical reasons.

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.

The types are:

SVt_NULL
SVt_IV
SVt_NV
SVt_RV
SVt_PV
SVt_PVIV
SVt_PVNV
SVt_PVMG
SVt_INVLIST
SVt_REGEXP
SVt_PVGV
SVt_PVLV
SVt_PVAV
SVt_PVHV
SVt_PVCV
SVt_PVFM
SVt_PVIO

These are most easily explained from the bottom up.

SVt_PVIO is for I/O objects, SVt_PVFM for formats, SVt_PVCV for subroutines,
SVt_PVHV for hashes and SVt_PVAV for arrays.

All the others are scalar types, that is, things that can be bound to a "$"
variable. For these, the internal types are mostly orthogonal to types in the
Perl language.

Hence, checking "SvTYPE(sv) < SVt_PVAV" is the best way to see whether something
is a scalar.

SVt_PVGV represents a typeglob. If !SvFAKE(sv), then it is a real, incoercible
typeglob. If SvFAKE(sv), then it is a scalar to which a typeglob has been
assigned. Assigning to it again will stop it from being a typeglob. SVt_PVLV
represents a scalar that delegates to another scalar behind the scenes. It is
used, e.g., for the return value of "substr" and for tied hash and array elements.
It can hold any scalar value, including a typeglob. SVt_REGEXP is for regular
expressions. SVt_INVLIST is for Perl core internal use only.

SVt_PVMG represents a "normal" scalar (not a typeglob, regular expression, or
delegate). Since most scalars do not need all the internal fields of a PVMG, we
save memory by allocating smaller structs when possible. All the other types are
just simpler forms of SVt_PVMG, with fewer internal fields.
SVt_NULL can only hold undef. SVt_IV can hold undef, an integer, or a reference.
(SVt_RV is an alias for SVt_IV, which exists for backward compatibility.) SVt_NV
can hold any of those or a double. SVt_PV can only hold undef or a string.
SVt_PVIV is a superset of SVt_PV and SVt_IV. SVt_PVNV is similar. SVt_PVMG can
hold anything SVt_PVNV can hold, but it can, but does not have to, be blessed or
magical.

SVt_INVLIST
Type flag for scalars. See "svtype".

SVt_IV Type flag for scalars. See "svtype".

SVt_NULL
Type flag for scalars. See "svtype".

SVt_NV Type flag for scalars. See "svtype".

SVt_PV Type flag for scalars. See "svtype".

SVt_PVAV
Type flag for arrays. See "svtype".

SVt_PVCV
Type flag for subroutines. See "svtype".

SVt_PVFM
Type flag for formats. See "svtype".

SVt_PVGV
Type flag for typeglobs. See "svtype".

SVt_PVHV
Type flag for hashes. See "svtype".

SVt_PVIO
Type flag for I/O objects. See "svtype".

SVt_PVIV
Type flag for scalars. See "svtype".

SVt_PVLV
Type flag for scalars. See "svtype".

SVt_PVMG
Type flag for scalars. See "svtype".

SVt_PVNV
Type flag for scalars. See "svtype".

SVt_REGEXP
Type flag for regular expressions. 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)

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

Creates a new SV containing the pad name.

SV* newSVpadname(PADNAME *pn)

newSVpvn_utf8
Creates a new SV and copies a string (which may contain "NUL" ("\0") characters)
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 "NUL" character (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. SV must be of type >= SVt_PV. One alternative is to call
"sv_grow" if you are not sure of the type of SV.

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 an 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 integer that must be
interpreted as unsigned. A non-negative integer whose value is within the range
of both an IV and a UV may be be flagged as either SvUOK or SVIOK.

bool SvIOK_UV(SV* sv)

SvIsCOW Returns a U32 value 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).

U32 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. The "len" variable will be set to the length of
the string (this is a macro, so don't use &len). See also "SvPVx" for a version
which guarantees to evaluate sv only once.

Note that there is no guarantee that the return value of "SvPV()" is equal to
"SvPVX(sv)", or that "SvPVX(sv)" contains valid data, or that successive calls to
"SvPV(sv)" will return the same pointer value each time. This is due to the way
that things like overloading and Copy-On-Write are handled. In these cases, the
return value may point to a temporary buffer or similar. If you absolutely need
the SvPVX field to be valid (for example, if you intend to write to it), then see
"SvPV_force".

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.
Prior to 5.9.3 it is not safe to execute this macro unless the SV's type >=
SVt_PV.

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 a string ("SvPOK"), and only a
string ("SvPOK_only"), by hook or by crook. You need force if you are going to
update the "SvPVX" directly. Processes get magic.

Note that coercing an arbitrary scalar into a plain PV will potentially strip
useful data from it. For example if the SV was "SvROK", then the referent will
have its reference count decremented, and the SV itself may be converted to an
"SvPOK" scalar with a string buffer containing a value such as "ARRAY(0x1234)".

char* SvPV_force(SV* sv, STRLEN len)

SvPV_force_nomg
Like "SvPV_force", but doesn't process get magic.

char* SvPV_force_nomg(SV* sv, STRLEN len)

SvPV_nolen
Like "SvPV" but doesn't set a length variable.

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
This is probably not what you want to use, you probably wanted "sv_usepvn_flags"
or "sv_setpvn" or "sv_setpvs".

Set the value of the PV pointer in "sv" to the Perl allocated "NUL"-terminated
string "val". See also "SvIV_set".

Remember to free the previous PV buffer. There are many things to check. Beware
that the existing pointer may be involved in copy-on-write or other mischief, so
do "SvOOK_off(sv)" and use "sv_force_normal" or "SvPV_force" (or check the SvIsCOW
flag) first to make sure this modification is safe. Then finally, if it is not a
COW, call "SvPV_free" to free the previous PV buffer.

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. sv may be NULL.

void SvREFCNT_dec(SV* sv)

SvREFCNT_dec_NN
Same as SvREFCNT_dec, 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.

void SvREFCNT_dec_NN(SV* sv)

SvREFCNT_inc
Increments the reference count of the given SV, returning the 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 integer that must be
interpreted as unsigned. A non-negative integer whose value is within the range
of both an IV and a UV may be be flagged as either SvUOK or SVIOK.

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. You
should use this after a call to SvPV() or one of its variants, in case any call to
string overloading updates the internal flag.

If you want to take into account the bytes pragma, use "DO_UTF8" instead.

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
evaluate "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 tmpRef)

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 (which may contain "NUL" ("\0") characters)
into it. The reference count for the SV is set to 1. If "len" is zero, Perl will
compute the length using strlen(), (which means if you use this option, that "s"
can't have embedded "NUL" characters and has to have a terminating "NUL" byte).

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 string 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 (which may contain "NUL" ("\0") characters)
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 the SvIsCOW flag (or READONLY and FAKE in 5.16 and earlier). 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 "NUL"-terminated string instead of a
string/length pair.

SV* newSVpvs(const char* s)

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

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

newSVpvs_share
Like "newSVpvn_share", but takes a literal "NUL"-terminated 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 existing 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. The reference count 1 is owned by "rv".

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 *sv, 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 "NUL"-terminated 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.

By default, the string appended is assumed to be valid UTF-8 if the SV has the
UTF-8 status set, and a string of bytes otherwise. One can force the appended
string to be interpreted as UTF-8 by supplying the "SV_CATUTF8" flag, and as bytes
by supplying the "SV_CATBYTES" flag; the SV or the string appended will be
upgraded to UTF-8 if necessary.

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 "NUL"-terminated 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 "NUL"-terminated 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". If
"ssv" is null, does nothing; otherwise modifies only "dsv". Handles 'get' magic
on both SVs, but no 'set' magic. See "sv_catsv_mg" and "sv_catsv_nomg".

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". If
"ssv" is null, does nothing; otherwise modifies only "dsv". If "flags" include
"SV_GMAGIC" bit set, will call "mg_get" on both SVs if appropriate. If "flags"
include "SV_SMAGIC", "mg_set" will be called on the modified SV afterward, if
appropriate. "sv_catsv", "sv_catsv_nomg", and "sv_catsv_mg" 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), or at least SvPOKp(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". On return, only SvPOK(sv) and SvPOKp(sv)
among the OK flags will be true.

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_flags
Implementation of sv_copypv and sv_copypv_nomg. Calls get magic iff flags include
SV_GMAGIC.

void sv_copypv_flags(SV *const dsv, SV *const ssv,
const I32 flags)

sv_copypv_nomg
Like sv_copypv, but doesn't invoke get magic first.

void sv_copypv_nomg(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, where fakery means "more than" a string: 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 this is a vstring,
drop the vstring magic. 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.

This function is expected to be used to signal to perl that this SV is about to be
written to, and any extra book-keeping needs to be taken care of. Hence, it
croaks on read-only values.

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. If "append" is not 0, the line is appended to the SV
instead of overwriting it. "append" should be set to the byte offset that the
appended string should start at in the SV (typically, "SvCUR(sv)" is a suitable
choice).

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

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

If the sv is the target of a weak reference then it returns the back references
structure associated with the sv; otherwise return NULL.

When returning a non-null result the type of the return is relevant. If it is an
AV then the elements of the AV are the weak reference RVs which point at this
item. If it is any other type then the item itself is the weak reference.

See also Perl_sv_add_backref(), Perl_sv_del_backref(), Perl_sv_kill_backrefs()

SV* sv_get_backrefs(SV *const sv)

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 and
sets the UTF8 flag appropriately. 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.

Use "sv_pos_b2u_flags" in preference, which correctly handles strings longer than
2Gb.

void sv_pos_b2u(SV *const sv, I32 *const offsetp)

sv_pos_b2u_flags
Converts the offset from a count of bytes from the start of the string, to a count
of the equivalent number of UTF-8 chars. Handles type coercion. flags is passed
to "SvPV_flags", and usually should be "SV_GMAGIC|SV_CONST_RETURN" to handle
magic.

STRLEN sv_pos_b2u_flags(SV *const sv,
STRLEN const offset, U32 flags)

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 offset 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 terminated with a "NUL" character.
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 (possibly containing embedded "NUL" characters) 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 on destination SV.
Calls 'get' magic on source SV. 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 "SV_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 Newx. It must be the start of a
Newx-ed block of memory, and not a pointer to the middle of it (beware of OOK and
copy-on-write), and not be from a non-Newx memory allocator like "malloc". The
string length, "len", must be supplied. By default this function will "Renew"
(i.e. realloc, 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
NOTE: this function is experimental and may change or be removed without notice.

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.

bool sv_utf8_decode(SV *const sv)

sv_utf8_downgrade
NOTE: this function is experimental and may change or be removed without notice.

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 a general purpose Unicode to byte encoding interface: use the Encode
extension for that.

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 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.

If "flags" has SV_FORCE_UTF8_UPGRADE set, this function assumes that the PV will
expand when converted to UTF-8, and skips the extra work of checking for that.
Typically this flag is used by a routine that has already parsed the string and
found such characters, and passes this information on so that the work doesn't
have to be repeated.

Returns the number of bytes in the converted string.

This is not 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_flags_grow
Like sv_utf8_upgrade_flags, but has an additional parameter "extra", which is the
number of unused bytes the string of 'sv' is guaranteed to have free after it upon
return. This allows the caller to reserve extra space that it intends to fill, to
avoid extra grows.

"sv_utf8_upgrade", "sv_utf8_upgrade_nomg", and "sv_utf8_upgrade_flags" are
implemented in terms of this function.

Returns the number of bytes in the converted string (not including the spares).

STRLEN sv_utf8_upgrade_flags_grow(SV *const sv,
const I32 flags,
STRLEN extra)

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
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_vcatpvfn_flags
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).

If called as "sv_vcatpvfn" or flags include "SV_GMAGIC", calls get magic.

Usually used via one of its frontends "sv_vcatpvf" and "sv_vcatpvf_mg".

void sv_vcatpvfn_flags(SV *const sv,
const char *const pat,
const STRLEN patlen,
va_list *const args,
SV **const svargs,
const I32 svmax,
bool *const maybe_tainted,
const U32 flags)

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

"Unicode Support" in perlguts has an introduction to this API.

See also "Character classification", and "Character case changing". Various functions
outside this section also work specially with Unicode. Search for the string "utf8" in
this document.

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

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).

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

bytes_to_utf8
NOTE: this function is experimental and may change or be removed without notice.

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"().

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

DO_UTF8 Returns a bool giving whether or not the PV in "sv" is to be treated as being
encoded in UTF-8.

You should use this after a call to "SvPV()" or one of its variants, in case any
call to string overloading updates the internal UTF-8 encoding flag.

bool DO_UTF8(SV* sv)

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 to the position 1 byte past the maximum point in "s1"
beyond which scanning will not continue under any circumstances. (This routine
assumes that UTF-8 encoded input strings are not malformed; malformed input can
cause it to read past "pe1"). 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)

isUTF8_CHAR
Returns the number of bytes beginning at "s" which form a legal UTF-8 (or UTF-
EBCDIC) encoded character, looking no further than "e - s" bytes into "s".
Returns 0 if the sequence starting at "s" through "e - 1" is not well-formed UTF-8

Note that an INVARIANT character (i.e. ASCII on non-EBCDIC machines) is a valid
UTF-8 character.

STRLEN isUTF8_CHAR(const U8 *s, const U8 *e)

is_ascii_string
This is a misleadingly-named synonym for "is_invariant_string". On ASCII-ish
platforms, the name isn't misleading: the ASCII-range characters are exactly the
UTF-8 invariants. But EBCDIC machines have more invariants than just the ASCII
characters, so "is_invariant_string" is preferred.

bool is_ascii_string(const U8 *s, STRLEN len)

is_invariant_string
Returns true iff the first "len" bytes of the string "s" are the same regardless
of the UTF-8 encoding of the string (or UTF-EBCDIC encoding on EBCDIC machines).
That is, if they are UTF-8 invariant. On ASCII-ish machines, all the ASCII
characters and only the ASCII characters fit this definition. On EBCDIC machines,
the ASCII-range characters are invariant, but so also are the C1 controls and
"\c?" (which isn't in the ASCII range on EBCDIC).

If "len" is 0, it will be calculated using strlen(s), (which means if you use this
option, that "s" can't have embedded "NUL" characters and has to have a
terminating "NUL" byte).

See also "is_utf8_string"(), "is_utf8_string_loclen"(), and
"is_utf8_string_loc"().

bool is_invariant_string(const U8 *s, STRLEN len)

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" can't have embedded "NUL" characters and
has to have a terminating "NUL" byte). Note that all characters being ASCII
constitute 'a valid UTF-8 string'.

See also "is_invariant_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 **ep)

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.

See also "sv_uni_display".

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
"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.

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

"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. "special" (usually, but not always,
a multicharacter mapping), is tried first.

"special" is a string, normally "NULL" or "". "NULL" means to not use any special
mappings; "" means to use the special mappings. Values other than these two are
treated as the name of the hash containing the special mappings, like
"utf8::ToSpecLower".

"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
Instead use "toFOLD_utf8".

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

to_utf8_lower
Instead use "toLOWER_utf8".

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

to_utf8_title
Instead use "toTITLE_utf8".

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

to_utf8_upper
Instead use "toUPPER_utf8".

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

utf8n_to_uvchr
THIS FUNCTION SHOULD BE USED IN ONLY VERY SPECIALIZED CIRCUMSTANCES. Most code
should use "utf8_to_uvchr_buf"() rather than call this directly.

Bottom level UTF-8 decode routine. Returns the native 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" (cast to "STRLEN") and return zero.

Note that this API requires disambiguation between successful decoding a "NUL"
character, and an error return (unless the UTF8_CHECK_ONLY flag is set), as in
both cases, 0 is returned. To disambiguate, upon a zero return, see if the first
byte of "s" is 0 as well. If so, the input was a "NUL"; if not, the input had an
error.

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.

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

utf8n_to_uvuni
Instead use "utf8_to_uvchr_buf", or rarely, "utf8n_to_uvchr".

This function was useful for code that wanted to handle both EBCDIC and ASCII
platforms with Unicode properties, but starting in Perl v5.20, the distinctions
between the platforms have mostly been made invisible to most code, so this
function is quite unlikely to be what you want. If you do need this precise
functionality, use instead "NATIVE_TO_UNI(utf8_to_uvchr_buf(...))" or
"NATIVE_TO_UNI(utf8n_to_uvchr(...))".

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

UTF8SKIP
returns the number of bytes in the UTF-8 encoded character whose first (perhaps
only) byte is pointed to by "s".

STRLEN UTF8SKIP(char* s)

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

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".

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

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_uvchr" 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_buf
DEPRECATED! It is planned to remove this function from a future release of Perl.
Do not use it for new code; remove it from existing code.

Only in very rare circumstances should code need to be dealing in Unicode (as
opposed to native) code points. In those few cases, use
"NATIVE_TO_UNI(utf8_to_uvchr_buf(...))" instead.

Returns the Unicode (not-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_uvchr" for details on
when the REPLACEMENT CHARACTER is returned.

UV utf8_to_uvuni_buf(const U8 *s, const U8 *send,
STRLEN *retlen)

UVCHR_SKIP
returns the number of bytes required to represent the code point "cp" when encoded
as UTF-8. "cp" is a native (ASCII or EBCDIC) code point if less than 255; a
Unicode code point otherwise.

STRLEN UVCHR_SKIP(UV cp)

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 "UVCHR_SKIP(uv)+1" (up to "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;

This function accepts any UV as input. To forbid or warn on non-Unicode code
points, or those that may be problematic, see "uvchr_to_utf8_flags".

U8* uvchr_to_utf8(U8 *d, UV uv)

uvchr_to_utf8_flags
Adds the UTF-8 representation of the native code point "uv" to the end of the
string "d"; "d" should have at least "UVCHR_SKIP(uv)+1" (up to "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_flags(d, uv, flags);

or, in most cases,

d = uvchr_to_utf8_flags(d, uv, 0);

This is the 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 affect how the
function handles a Unicode non-character. And likewise, the UNICODE_WARN_SUPER
and UNICODE_DISALLOW_SUPER flags affect the handling of 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* uvchr_to_utf8_flags(U8 *d, UV uv, UV flags)

uvoffuni_to_utf8_flags
THIS FUNCTION SHOULD BE USED IN ONLY VERY SPECIALIZED CIRCUMSTANCES. Instead,
Almost all code should use "uvchr_to_utf8" or "uvchr_to_utf8_flags".

This function is like them, but the input is a strict Unicode (as opposed to
native) code point. Only in very rare circumstances should code not be using the
native code point.

For details, see the description for "uvchr_to_utf8_flags".

U8* uvoffuni_to_utf8_flags(U8 *d, UV uv, UV flags)

uvuni_to_utf8_flags
Instead you almost certainly want to use "uvchr_to_utf8" or "uvchr_to_utf8_flags".

This function is a deprecated synonym for "uvoffuni_to_utf8_flags", which itself,
while not deprecated, should be used only in isolated circumstances. These
functions were useful for code that wanted to handle both EBCDIC and ASCII
platforms with Unicode properties, but starting in Perl v5.20, the distinctions
between the platforms have mostly been made invisible to most code, so this
function is quite unlikely to be what you want.

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

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

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

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_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;

Versioning

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)

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)

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)

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.
Functions that are not listed in this document are not intended for public use, and should
NOT be used under any circumstances.

If you use one of the undocumented functions below, 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
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_memory_wrap
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_eval
dump_form
dump_indent
dump_mstats
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_set
hv_rand_set
hv_riter_p
hv_riter_set
ibcmp_utf8
init_global_struct
init_stacks
init_tm
instr
is_lvalue_sub
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_lstat
my_memcmp
my_memset
my_pclose
my_popen
my_popen_list
my_setenv
my_socketpair
my_stat
my_strftime
newANONATTRSUB
newANONHASH
newANONLIST
newANONSUB
newATTRSUB
newAVREF
newCVREF
newFORM
newGVREF
newGVgen
newGVgen_flags
newHVREF
newHVhv
newIO
newMYSUB
newPROG
newRV
newSUB
newSVREF
newSVpvf_nocontext
new_stackinfo
ninstr
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_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
seed
set_context
set_numeric_local
set_numeric_radix
set_numeric_standard
share_hek
si_dup
ss_dup
stack_grow
start_subparse
str_to_version
sv_2iv
sv_2pv
sv_2uv
sv_catpvf_mg_nocontext
sv_catpvf_nocontext
sv_dup
sv_dup_inc
sv_peek
sv_pvn_nomg
sv_setpvf_mg_nocontext
sv_setpvf_nocontext
swash_fetch
swash_init
sys_init
sys_init3
sys_intern_clear
sys_intern_dup
sys_intern_init
sys_term
taint_env
taint_proper
unlnk
unsharepvn
utf16_to_utf8
utf16_to_utf8_reversed
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 <[email protected]>. 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 <[email protected]>.

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

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