Manual - Section 1: perlapi

NAME

perlapi - autogenerated documentation for the perl public API

DESCRIPTION

This file contains the documentation of the perl public API generated by embed.pl, specifically a listing of functions, macros, flags, and variables that may be used by extension writers. The interfaces of any functions that are not listed here are subject to change without notice. For this reason, blindly using functions listed in proto.h is to be avoided when writing extensions.

Note that all Perl API global variables must be referenced with the

PL_

prefix. Some macros are provided for compatibility with the older, unadorned names, but this support may be disabled in a future release.

The listing is alphabetical, case insensitive.

``Gimme'' Values

GIMME A backward-compatible version of
GIMME_V
which can only return
G_SCALAR
or
G_ARRAY
; in a void context, it returns
G_SCALAR
. Deprecated. Use
GIMME_V
instead.

U32 GIMME

GIMME_V The XSUB-writer’s equivalent to Perl’s
wantarray
. Returns
G_VOID
,
G_SCALAR
or
G_ARRAY
for void, scalar or list context, respectively.

U32 GIMME_V

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

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

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

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

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

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

Array Manipulation Functions

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

int AvFILL(AV* av)

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

void av_clear(AV* ar)

av_create_and_push Push an SV onto the end of the array, creating the array if necessary. A small internal helper function to remove a commonly duplicated idiom.
NOTE: this function is experimental and may change or be removed without notice.

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

av_create_and_unshift_one Unshifts an SV onto the beginning of the array, creating the array if necessary. A small internal helper function to remove a commonly duplicated idiom.
NOTE: this function is experimental and may change or be removed without notice.

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

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

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

av_exists Returns true if the element indexed by
key
has been initialized.
This relies on the fact that uninitialized array elements are set to
&PL_sv_undef
.

bool av_exists(AV* ar, I32 key)

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

void av_extend(AV* ar, I32 key)

av_fetch Returns the SV at the specified index in the array. The
key
is the index. If
lval
is set then the fetch will be part of a store. Check that the return value is non-null before dereferencing it to a
SV*
.
See Understanding the Magic of Tied Hashes and Arrays in perlguts for more information on how to use this function on tied arrays.

SV** av_fetch(AV* ar, I32 key, I32 lval)

av_fill Set the highest index in the array to the given number, equivalent to Perl’s
$#array = $fill;
.
The number of elements in the an array will be
fill + 1
after av_fill() returns. If the array was previously shorter then the additional elements appended are set to
PL_sv_undef
. If the array was longer, then the excess elements are freed.
av_fill(av, -1)
is the same as
av_clear(av)
.

void av_fill(AV* ar, I32 fill)

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

I32 av_len(const AV* ar)

av_make Creates a new AV and populates it with a list of SVs. The SVs are copied into the array, so they may be freed after the call to av_make. The new AV will have a reference count of 1.

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

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

SV* av_pop(AV* ar)

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

void av_push(AV* ar, SV* val)

av_shift Shifts an SV off the beginning of the array.

SV* av_shift(AV* ar)

av_store Stores an SV in an array. The array index is specified as
key
. The return value will be NULL if the operation failed or if the value did not need to be actually stored within the array (as in the case of tied arrays). Otherwise it can be dereferenced to get the original
SV*
. Note that the caller is responsible for suitably incrementing the reference count of
val
before the call, and decrementing it if the function returned NULL.
See Understanding the Magic of Tied Hashes and Arrays in perlguts for more information on how to use this function on tied arrays.

SV** av_store(AV* ar, I32 key, SV* val)

av_undef Undefines the array. Frees the memory used by the array itself.

void av_undef(AV* ar)

av_unshift Unshift the given number of
undef
values onto the beginning of the array. The array will grow automatically to accommodate the addition. You must then use
av_store
to assign values to these new elements.

void av_unshift(AV* ar, I32 num)

get_av Returns the AV of the specified Perl array. If
create
is set and the Perl variable does not exist then it will be created. If
create
is not set and the variable does not exist then NULL is returned.
NOTE: the perl_ form of this function is deprecated.

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

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

AV* newAV()

sortsv Sort an array. Here is an example:

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

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

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

sortsv_flags Sort an array, with various options.

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

Callback Functions

call_argv Performs a callback to the specified Perl sub. See perlcall.
NOTE: the perl_ form of this function is deprecated.

I32 call_argv(const char* sub_name, I32 flags, char** argv)

call_method Performs a callback to the specified Perl method. The blessed object must be on the stack. See perlcall.
NOTE: the perl_ form of this function is deprecated.

I32 call_method(const char* methname, I32 flags)

call_pv Performs a callback to the specified Perl sub. See perlcall.
NOTE: the perl_ form of this function is deprecated.

I32 call_pv(const char* sub_name, I32 flags)

call_sv Performs a callback to the Perl sub whose name is in the SV. See perlcall.
NOTE: the perl_ form of this function is deprecated.

I32 call_sv(SV* sv, I32 flags)

ENTER Opening bracket on a callback. See
LEAVE
and perlcall.

ENTER;

eval_pv Tells Perl to
eval
the given string and return an SV* result.
NOTE: the perl_ form of this function is deprecated.

SV* eval_pv(const char* p, I32 croak_on_error)

eval_sv Tells Perl to
eval
the string in the SV.
NOTE: the perl_ form of this function is deprecated.

I32 eval_sv(SV* sv, I32 flags)

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

FREETMPS;

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

LEAVE;

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

SAVETMPS;

Character classes

isALNUM Returns a boolean indicating whether the C
char
is an ASCII alphanumeric character (including underscore) or digit.

bool isALNUM(char ch)

isALPHA Returns a boolean indicating whether the C
char
is an ASCII alphabetic character.

bool isALPHA(char ch)

isDIGIT Returns a boolean indicating whether the C
char
is an ASCII digit.

bool isDIGIT(char ch)

isLOWER Returns a boolean indicating whether the C
char
is a lowercase character.

bool isLOWER(char ch)

isSPACE Returns a boolean indicating whether the C
char
is whitespace.

bool isSPACE(char ch)

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

bool isUPPER(char ch)

toLOWER Converts the specified character to lowercase.

char toLOWER(char ch)

toUPPER Converts the specified character to uppercase.

char toUPPER(char ch)

Cloning an interpreter

perl_clone Create and return a new interpreter by cloning the current one.
perl_clone takes these flags as parameters:
CLONEf_COPY_STACKS - is used to, well, copy the stacks also, without it we only clone the data and zero the stacks, with it we copy the stacks and the new perl interpreter is ready to run at the exact same point as the previous one. The pseudo-fork code uses COPY_STACKS while the threads->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* interp, UV flags)

CV Manipulation Functions

CvSTASH Returns the stash of the CV.

HV* CvSTASH(CV* cv)

get_cv Uses
strlen
to get the length of
name
, then calls
get_cvn_flags
.
NOTE: the perl_ form of this function is deprecated.

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

get_cvn_flags Returns the CV of the specified Perl subroutine.
flags
are passed to
gv_fetchpvn_flags
. If
GV_ADD
is set and the Perl subroutine does not exist then it will be declared (which has the same effect as saying
sub name;
). If
GV_ADD
is not set and the subroutine does not exist then NULL is returned.
NOTE: the perl_ form of this function is deprecated.

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

Embedding Functions

cv_undef Clear out all the active components of a CV. This can happen either by an explicit
undef &foo
, or by the reference count going to zero. In the former case, we keep the CvOUTSIDE pointer, so that any anonymous children can still follow the full lexical scope chain.

void cv_undef(CV* cv)

load_module Loads the module whose name is pointed to by the string part of name. Note that the actual module name, not its filename, should be given. Eg, Foo::Bar instead of Foo/Bar.pm. flags can be any of PERL_LOADMOD_DENY, PERL_LOADMOD_NOIMPORT, or PERL_LOADMOD_IMPORT_OPS (or 0 for no flags). ver, if specified, provides version semantics similar to
use Foo::Bar VERSION
. The optional trailing SV* arguments can be used to specify arguments to the module’s import() method, similar to
use Foo::Bar VERSION LIST
.

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

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

int nothreadhook()

perl_alloc Allocates a new Perl interpreter. See perlembed.

PerlInterpreter* perl_alloc()

perl_construct Initializes a new Perl interpreter. See perlembed.

void perl_construct(PerlInterpreter* interp)

perl_destruct Shuts down a Perl interpreter. See perlembed.

int perl_destruct(PerlInterpreter* interp)

perl_free Releases a Perl interpreter. See perlembed.

void perl_free(PerlInterpreter* interp)

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

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

perl_run Tells a Perl interpreter to run. See perlembed.

int perl_run(PerlInterpreter* interp)

require_pv Tells Perl to
require
the file named by the string argument. It is analogous to the Perl code
eval "require $file"
. It’s even implemented that way; consider using load_module instead.
NOTE: the perl_ form of this function is deprecated.

void require_pv(const char* pv)

Functions in file dump.c

pv_display
char *pv_display(SV *dsv, const char *pv, STRLEN cur, STRLEN len, STRLEN pvlim, U32 flags)

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
|const STRLEN count|const STRLEN max |STRLEN const *escaped, const U32 flags

Escapes at most the first count chars of pv and puts the results into dsv such that the size of the escaped string will not exceed max chars and will not contain any incomplete escape sequences.
If flags contains PERL_PV_ESCAPE_QUOTE then any double quotes in the string will also be escaped.
Normally the SV will be cleared before the escaped string is prepared, but when PERL_PV_ESCAPE_NOCLEAR is set this will not occur.
If PERL_PV_ESCAPE_UNI is set then the input string is treated as Unicode, if PERL_PV_ESCAPE_UNI_DETECT is set then the input string is scanned using
is_utf8_string()
to determine if it is Unicode.
If PERL_PV_ESCAPE_ALL is set then all input chars will be output using
\x01F1
style escapes, otherwise only chars above 255 will be escaped using this style, other non printable chars will use octal or common escaped patterns like
\n
. If PERL_PV_ESCAPE_NOBACKSLASH then all chars below 255 will be treated as printable and will be output as literals.
If PERL_PV_ESCAPE_FIRSTCHAR is set then only the first char of the string will be escaped, regardles of max. If the string is utf8 and the chars value is >255 then it will be returned as a plain hex sequence. Thus the output will either be a single char, an octal escape sequence, a special escape like
\n
or a 3 or more digit 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.
NOTE: the perl_ form of this function is deprecated.

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

pv_pretty
|const STRLEN count|const STRLEN max\ |const char const *start_color| const char const *end_color\ |const U32 flags

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.
NOTE: the perl_ form of this function is deprecated.

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

Functions in file mathoms.c

gv_fetchmethod See gv_fetchmethod_autoload.

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

pack_cat The engine implementing pack() Perl function. Note: parameters next_in_list and flags are not used. This call should not be used; use packlist instead.

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

sv_2pvbyte_nolen Return a pointer to the byte-encoded representation of the SV. May cause the SV to be downgraded from UTF-8 as a side-effect.
Usually accessed via the
SvPVbyte_nolen
macro.

char* sv_2pvbyte_nolen(SV* sv)

sv_2pvutf8_nolen Return a pointer to the UTF-8-encoded representation of the SV. May cause the SV to be upgraded to UTF-8 as a side-effect.
Usually accessed via the
SvPVutf8_nolen
macro.

char* sv_2pvutf8_nolen(SV* sv)

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

sv_catpvn_mg Like
sv_catpvn
, but also handles ’set’ magic.

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

sv_catsv_mg Like
sv_catsv
, but also handles ’set’ magic.

void sv_catsv_mg(SV *dstr, SV *sstr)

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 *len)

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

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

sv_pvutf8 Use the
SvPVutf8_nolen
macro instead

char* sv_pvutf8(SV *sv)

sv_pvutf8n A private implementation of the
SvPVutf8
macro for compilers which can’t cope with complex macro expressions. Always use the macro instead.

char* sv_pvutf8n(SV *sv, STRLEN *len)

sv_taint Taint an SV. Use
SvTAINTED_on
instead. void sv_taint(SV* sv)

sv_unref Unsets the RV status of the SV, and decrements the reference count of whatever was being referenced by the RV. This can almost be thought of as a reversal of
newSVrv
. This is
sv_unref_flags
with the
flag
being zero. See
SvROK_off
.

void sv_unref(SV* sv)

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

void sv_usepvn(SV* sv, char* ptr, STRLEN len)

sv_usepvn_mg Like
sv_usepvn
, but also handles ’set’ magic.

void sv_usepvn_mg(SV *sv, char *ptr, STRLEN len)

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

UV sv_uv(SV* sv)

unpack_str The engine implementing unpack() Perl function. Note: parameters strbeg, new_s and ocnt are not used. This call should not be used, use unpackstring instead.

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

Functions in file pp_ctl.c

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

CV* find_runcv(U32 *db_seqp)

Functions in file pp_pack.c

packlist The engine implementing pack() Perl function.

void packlist(SV *cat, const char *pat, const char *patend, SV **beglist, SV **endlist)

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

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

GV Functions

GvSV Return the SV from the GV.

SV* GvSV(GV* gv)

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

SV* gv_const_sv(GV* gv)

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

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

gv_fetchmethod_autoload Returns the glob which contains the subroutine to call to invoke the method on the
stash
. In fact in the presence of autoloading this may be the glob for AUTOLOAD. In this case the corresponding variable
$AUTOLOAD
is already setup.
The third parameter of
gv_fetchmethod_autoload
determines whether AUTOLOAD lookup is performed if the given method is not present: non-zero means yes, look for AUTOLOAD; zero means no, don’t look for AUTOLOAD. Calling
gv_fetchmethod
is equivalent to calling
gv_fetchmethod_autoload
with a non-zero
autoload
parameter.
These functions grant
"SUPER"
token as a prefix of the method name. Note that if you want to keep the returned glob for a long time, you need to check for it being AUTOLOAD, since at the later time the call may load a different subroutine due to
$AUTOLOAD
changing its value. Use the glob created via a side effect to do this.
These functions have the same side-effects and as
gv_fetchmeth
with
level==0
.
name
should be writable if contains
:
or
. The warning against passing the GV returned by
gv_fetchmeth
to
call_sv
apply equally to these functions.

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

gv_fetchmeth_autoload Same as gv_fetchmeth(), but looks for autoloaded subroutines too. Returns a glob for the subroutine.
For an autoloaded subroutine without a GV, will create a GV even if
level < 0
. For an autoloaded subroutine without a stub, GvCV() of the result may be zero.

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

gv_stashpv Returns a pointer to the stash for a specified package. Uses
strlen
to determine the length of
name
, then calls
gv_stashpvn()
.

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

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

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

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

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

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

HV* gv_stashsv(SV* sv, I32 flags)

Handy Values

Nullav Null AV pointer.

Nullch Null character pointer.

Nullcv Null CV pointer.

Nullhv Null HV pointer.

Nullsv Null SV pointer.

Hash Manipulation Functions

get_hv Returns the HV of the specified Perl hash. If
create
is set and the Perl variable does not exist then it will be created. If
create
is not set and the variable does not exist then NULL is returned.
NOTE: the perl_ form of this function is deprecated.

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

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

HeHASH Returns the computed hash stored in the hash entry.

U32 HeHASH(HE* he)

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

void* HeKEY(HE* he)

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

STRLEN HeKLEN(HE* he)

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

char* HePV(HE* he, STRLEN len)

HeSVKEY Returns the key as an
SV*
, or
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)

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

SV* HeVAL(HE* he)

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

char* HvNAME(HV* stash)

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

void hv_assert(HV* tb)

hv_clear Clears a hash, making it empty.

void hv_clear(HV* tb)

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

void hv_clear_placeholders(HV* hb)

hv_delete Deletes a key/value pair in the hash. The value SV is removed from the hash and returned to the caller. The
klen
is the length of the key. The
flags
value will normally be zero; if set to G_DISCARD then NULL will be returned.

SV* hv_delete(HV* tb, const char* key, I32 klen, I32 flags)

hv_delete_ent Deletes a key/value pair in the hash. The value SV is removed from the hash and returned to the caller. The
flags
value will normally be zero; if set to G_DISCARD then NULL will be returned.
hash
can be a valid precomputed hash value, or 0 to ask for it to be computed.

SV* hv_delete_ent(HV* tb, SV* key, I32 flags, U32 hash)

hv_exists Returns a boolean indicating whether the specified hash key exists. The
klen
is the length of the key.

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

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

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

hv_fetch Returns the SV which corresponds to the specified key in the hash. The
klen
is the length of the key. If
lval
is set then the fetch will be part of a store. Check that the return value is non-null before dereferencing it to an
SV*
.
See Understanding the Magic of Tied Hashes and Arrays in perlguts for more information on how to use this function on tied hashes.

SV** hv_fetch(HV* tb, const char* key, I32 klen, I32 lval)

hv_fetchs Like
hv_fetch
, but takes a literal string instead of a string/length pair.

SV** hv_fetchs(HV* tb, const char* key, I32 lval)

hv_fetch_ent Returns the hash entry which corresponds to the specified key in the hash.
hash
must be a valid precomputed hash number for the given
key
, or 0 if you want the function to compute it. IF
lval
is set then the fetch will be part of a store. Make sure the return value is non-null before accessing it. The return value when
tb
is a tied hash is a pointer to a static location, so be sure to make a copy of the structure if you need to store it somewhere.
See Understanding the Magic of Tied Hashes and Arrays in perlguts for more information on how to use this function on tied hashes.

HE* hv_fetch_ent(HV* tb, SV* key, I32 lval, U32 hash)

hv_iterinit Prepares a starting point to traverse a hash table. Returns the number of keys in the hash (i.e. the same as
HvKEYS(tb)
). The return value is currently only meaningful for hashes without tie magic.
NOTE: Before version 5.004_65,
hv_iterinit
used to return the number of hash buckets that happen to be in use. If you still need that esoteric value, you can get it through the macro
HvFILL(tb)
.

I32 hv_iterinit(HV* tb)

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

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

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

SV* hv_iterkeysv(HE* entry)

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

HE* hv_iternext(HV* tb)

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

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

hv_iternext_flags Returns entries from a hash iterator. See
hv_iterinit
and
hv_iternext
. The
flags
value will normally be zero; if HV_ITERNEXT_WANTPLACEHOLDERS is set the placeholders keys (for restricted hashes) will be returned in addition to normal keys. By default placeholders are automatically skipped over. Currently a placeholder is implemented with a value that is
&Perl_sv_placeholder
. Note that the implementation of placeholders and restricted hashes may change, and the implementation currently is insufficiently abstracted for any change to be tidy.
NOTE: this function is experimental and may change or be removed without notice.

HE* hv_iternext_flags(HV* tb, I32 flags)

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

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

hv_magic Adds magic to a hash. See
sv_magic
.

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

hv_scalar Evaluates the hash in scalar context and returns the result. Handles magic when the hash is tied.

SV* hv_scalar(HV* hv)

hv_store Stores an SV in a hash. The hash key is specified as
key
and
klen
is the length of the key. The
hash
parameter is the precomputed hash value; if it is zero then Perl will compute it. The return value will be NULL if the operation failed or if the value did not need to be actually stored within the hash (as in the case of tied hashes). Otherwise it can be dereferenced to get the original
SV*
. Note that the caller is responsible for suitably incrementing the reference count of
val
before the call, and decrementing it if the function returned NULL. Effectively a successful hv_store takes ownership of one reference to
val
. This is usually what you want; a newly created SV has a reference count of one, so if all your code does is create SVs then store them in a hash, hv_store will own the only reference to the new SV, and your code doesn’t need to do anything further to tidy up. hv_store is not implemented as a call to hv_store_ent, and does not create a temporary SV for the key, so if your key data is not already in SV form then use hv_store in preference to hv_store_ent.
See Understanding the Magic of Tied Hashes and Arrays in perlguts for more information on how to use this function on tied hashes.

SV** hv_store(HV* tb, const char* key, I32 klen, SV* val, U32 hash)

hv_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* tb, SV* key, SV* val, U32 hash)

hv_undef Undefines the hash.

void hv_undef(HV* tb)

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

HV* newHV()

Magical Functions

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

int mg_clear(SV* sv)

mg_copy Copies the magic from one SV to another. See
sv_magic
.

int mg_copy(SV* sv, SV* nsv, const char* key, I32 klen)

mg_find Finds the magic pointer for type matching the SV. See
sv_magic
.

MAGIC* mg_find(const SV* sv, int type)

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

int mg_free(SV* sv)

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

int mg_get(SV* sv)

mg_length Report on the SV’s length. See
sv_magic
.

U32 mg_length(SV* sv)

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

void mg_magical(SV* sv)

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

int mg_set(SV* sv)

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

void SvGETMAGIC(SV* sv)

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

void SvLOCK(SV* sv)

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

void SvSETMAGIC(SV* sv)

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

void SvSetMagicSV(SV* dsb, SV* ssv)

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

void SvSetMagicSV_nosteal(SV* dsv, SV* ssv)

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

void SvSetSV(SV* dsb, SV* ssv)

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

void SvSetSV_nosteal(SV* dsv, SV* ssv)

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

void SvSHARE(SV* sv)

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

void SvUNLOCK(SV* sv)

Memory Management

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

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

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

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

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

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

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

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

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

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

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

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

Newxz The XSUB-writer’s interface to the C
malloc
function. The allocated memory is zeroed with
memzero
. See also
Newx
.

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

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

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

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

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

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

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

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

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

Renew The XSUB-writer’s interface to the C
realloc
function.

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

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

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

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

void Safefree(void* ptr)

savepv Perl’s version of
strdup()
. Returns a pointer to a newly allocated string which is a duplicate of
pv
. The size of the string is determined by
strlen()
. The memory allocated for the new string can be freed with the
Safefree()
function.

char* savepv(const char* pv)

savepvn Perl’s version of what
strndup()
would be if it existed. Returns a pointer to a newly allocated string which is a duplicate of the first
len
bytes from
pv
, plus a trailing NUL byte. The memory allocated for the new string can be freed with the
Safefree()
function.

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

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

char* savepvs(const char* s)

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

char* savesharedpv(const char* pv)

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

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

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

char* savesvpv(SV* sv)

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

void StructCopy(type src, type dest, type)

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

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

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

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

Miscellaneous Functions

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

void fbm_compile(SV* sv, U32 flags)

fbm_instr Returns the location of the SV in the string delimited by
str
and
strend
. It returns
NULL
if the string can’t be found. The
sv
does not have to be fbm_compiled, but the search will not be as fast then.

char* fbm_instr(unsigned char* big, unsigned char* bigend, SV* littlesv, U32 flags)

form Takes a sprintf-style format pattern and conventional (non-SV) arguments and returns the formatted string.

(char *) Perl_form(pTHX_ const char* pat, ...)

can be used any place a string (char *) is required:

char * s = Perl_form("%d.%d",major,minor);

Uses a single private buffer so if you want to format several strings you must explicitly copy the earlier strings away (and free the copies when you are done).

char* form(const char* pat, ...)

getcwd_sv Fill the sv with current working directory

int getcwd_sv(SV* sv)

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

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

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

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

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

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

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

SV *sv = new_version(SV *ver);

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

SV* new_version(SV *ver)

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 *vstr, SV *sv, bool qv)

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

bool strEQ(char* s1, char* s2)

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

bool strGE(char* s1, char* s2)

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

bool strGT(char* s1, char* s2)

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

bool strLE(char* s1, char* s2)

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

bool strLT(char* s1, char* s2)

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

bool strNE(char* s1, char* s2)

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

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

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

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

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

bool sv_destroyable(SV *sv)

sv_nosharing Dummy routine which shares an SV when there is no sharing module present. Or locks it. Or unlocks it. In other words, ignores its single SV argument. Exists to avoid test for a NULL function pointer and because it could potentially warn under some level of strict-ness.

void sv_nosharing(SV *sv)

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

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

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

SV* upg_version(SV *ver, bool qv)

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

int vcmp(SV *lvs, SV *rvs)

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.

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.

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

SV* vstringify(SV *vs)

vverify Validates that the SV contains a valid version object.

bool vverify(SV *vobj);

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

bool vverify(SV *vs)

MRO Functions

mro_get_linear_isa Returns either
mro_get_linear_isa_c3
or
mro_get_linear_isa_dfs
for the given stash, dependant upon which MRO is in effect for that 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)

Multicall Functions

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

dMULTICALL;

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

MULTICALL;

POP_MULTICALL Closing bracket for a lightweight callback. See Lightweight Callbacks in perlcall.

POP_MULTICALL;

PUSH_MULTICALL Opening bracket for a lightweight callback. See Lightweight Callbacks in perlcall.

PUSH_MULTICALL;

Numeric functions

grok_bin converts a string representing a binary number to numeric form.
On entry start and *len give the string to scan, *flags gives conversion flags, and result should be NULL or a pointer to an NV. The scan stops at the end of the string, or the first invalid character. Unless
PERL_SCAN_SILENT_ILLDIGIT
is set in *flags, encountering an invalid character will also trigger a warning. On return *len is set to the length of the scanned string, and *flags gives output flags.
If the value is <=
UV_MAX
it is returned as a UV, the output flags are clear, and nothing is written to *result. If the value is > UV_MAX
grok_bin
returns UV_MAX, sets
PERL_SCAN_GREATER_THAN_UV_MAX
in the output flags, and writes the value to *result (or the value is discarded if result is NULL).
The binary number may optionally be prefixed with 0b or b unless
PERL_SCAN_DISALLOW_PREFIX
is set in *flags on entry. If
PERL_SCAN_ALLOW_UNDERSCORES
is set in *flags then the binary number may use ’_’ characters to separate digits.

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

grok_hex converts a string representing a hex number to numeric form.
On entry start and *len give the string to scan, *flags gives conversion flags, and result should be NULL or a pointer to an NV. The scan stops at the end of the string, or the first invalid character. Unless
PERL_SCAN_SILENT_ILLDIGIT
is set in *flags, encountering an invalid character will also trigger a warning. On return *len is set to the length of the scanned string, and *flags gives output flags.
If the value is <= UV_MAX it is returned as a UV, the output flags are clear, and nothing is written to *result. If the value is > UV_MAX
grok_hex
returns UV_MAX, sets
PERL_SCAN_GREATER_THAN_UV_MAX
in the output flags, and writes the value to *result (or the value is discarded if result is NULL).
The hex number may optionally be prefixed with 0x or x unless
PERL_SCAN_DISALLOW_PREFIX
is set in *flags on entry. If
PERL_SCAN_ALLOW_UNDERSCORES
is set in *flags then the hex number may use ’_’ characters to separate digits.

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

grok_number Recognise (or not) a number. The type of the number is returned (0 if unrecognised), otherwise it is a bit-ORed combination of IS_NUMBER_IN_UV, IS_NUMBER_GREATER_THAN_UV_MAX, IS_NUMBER_NOT_INT, IS_NUMBER_NEG, IS_NUMBER_INFINITY, IS_NUMBER_NAN (defined in perl.h).
If the value of the number can fit an in UV, it is returned in the *valuep IS_NUMBER_IN_UV will be set to indicate that *valuep is valid, IS_NUMBER_IN_UV will never be set unless *valuep is valid, but *valuep may have been assigned to during processing even though IS_NUMBER_IN_UV is not set on return. If valuep is NULL, IS_NUMBER_IN_UV will be set for the same cases as when valuep is non-NULL, but no actual assignment (or SEGV) will occur.
IS_NUMBER_NOT_INT will be set with IS_NUMBER_IN_UV if trailing decimals were seen (in which case *valuep gives the true value truncated to an integer), and IS_NUMBER_NEG if the number is negative (in which case *valuep holds the absolute value). IS_NUMBER_IN_UV is not set if e notation was used or the number is larger than a UV.

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

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

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

grok_oct converts a string representing an octal number to numeric form.
On entry start and *len give the string to scan, *flags gives conversion flags, and result should be NULL or a pointer to an NV. The scan stops at the end of the string, or the first invalid character. Unless
PERL_SCAN_SILENT_ILLDIGIT
is set in *flags, encountering an invalid character will also trigger a warning. On return *len is set to the length of the scanned string, and *flags gives output flags.
If the value is <= UV_MAX it is returned as a UV, the output flags are clear, and nothing is written to *result. If the value is > UV_MAX
grok_oct
returns UV_MAX, sets
PERL_SCAN_GREATER_THAN_UV_MAX
in the output flags, and writes the value to *result (or the value is discarded if result is NULL).
If
PERL_SCAN_ALLOW_UNDERSCORES
is set in *flags then the octal number may use ’_’ characters to separate digits.

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

Perl_signbit Return a non-zero integer if the sign bit on an NV is set, and 0 if it is not.
If Configure detects this system has a signbit() that will work with our NVs, then we just use it via the #define in perl.h. Otherwise, fall back on this implementation. As a first pass, this gets everything right except -0.0. Alas, catching -0.0 is the main use for this function, so this is not too helpful yet. Still, at least we have the scaffolding in place to support other systems, should that prove useful.
Configure notes: This function is called ’Perl_signbit’ instead of a plain ’signbit’ because it is easy to imagine a system having a signbit() function or macro that doesn’t happen to work with our particular choice of NVs. We shouldn’t just re-#define signbit as Perl_signbit and expect the standard system headers to be happy. Also, this is a no-context function (no pTHX_) because Perl_signbit() is usually re-#defined in perl.h as a simple macro call to the system’s signbit(). Users should just always call Perl_signbit().
NOTE: this function is experimental and may change or be removed without notice.

int Perl_signbit(NV f)

scan_bin For backwards compatibility. Use
grok_bin
instead.

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

scan_hex For backwards compatibility. Use
grok_hex
instead.

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

scan_oct For backwards compatibility. Use
grok_oct
instead.

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

Optree Manipulation Functions

cv_const_sv If
cv
is a constant sub eligible for inlining. returns the constant value returned by the sub. Otherwise, returns NULL.
Constant subs can be created with
newCONSTSUB
or as described in Constant Functions in perlsub.

SV* cv_const_sv(CV* cv)

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

CV* newCONSTSUB(HV* stash, const char* name, 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.

Pad Data Structures

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

SV* pad_sv(PADOFFSET po)

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_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) && (tmpsv = (SV*)SvRV(sv)) && SvTYPE(tmpsv) == SVt_PVMG && (tmpmg = mg_find(tmpsv, PERL_MAGIC_qr))) { return (REGEXP *)tmpmg->mg_obj; }

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

REGEXP * SvRX(SV *sv)

SvRXOK Returns a boolean indicating whether the SV contains qr magic (PERL_MAGIC_qr).
If you want to do something with the REGEXP* later use SvRX instead and check for NULL.

bool SvRXOK(SV* sv)

Simple Exception Handling Macros

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

dXCPT;

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

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

XCPT_RETHROW;

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

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

Stack Manipulation Macros

dMARK Declare a stack marker variable,
mark
, for the XSUB. See
MARK
and
dORIGMARK
.

dMARK;

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

dORIGMARK;

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

dSP;

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

void EXTEND(SP, int nitems)

MARK Stack marker variable for the XSUB. See
dMARK
.

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

void mPUSHi(IV iv)

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

void mPUSHn(NV nv)

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

void mPUSHp(char* str, STRLEN len)

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

void mPUSHu(UV uv)

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

void mXPUSHi(IV iv)

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

void mXPUSHn(NV nv)

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

void mXPUSHp(char* str, STRLEN len)

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

void mXPUSHu(UV uv)

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

POPi Pops an integer off the stack.

IV POPi

POPl Pops a long off the stack.

long POPl

POPn Pops a double off the stack.

NV POPn

POPp Pops a string off the stack. Deprecated. New code should use POPpx.

char* POPp

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

char* POPpbytex

POPpx Pops a string off the stack.

char* POPpx

POPs Pops an SV off the stack.

SV* POPs

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

void PUSHi(IV iv)

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

void PUSHMARK(SP)

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

void PUSHmortal()

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

void PUSHn(NV nv)

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

void PUSHp(char* str, STRLEN len)

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

void PUSHs(SV* sv)

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

void PUSHu(UV uv)

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

PUTBACK;

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

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

SPAGAIN;

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

void XPUSHi(IV iv)

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

void XPUSHmortal()

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

void XPUSHn(NV nv)

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

void XPUSHp(char* str, STRLEN len)

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

void XPUSHs(SV* sv)

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

void XPUSHu(UV uv)

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

void XSRETURN(int nitems)

XSRETURN_EMPTY Return an empty list from an XSUB immediately.

XSRETURN_EMPTY;

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

void XSRETURN_IV(IV iv)

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

XSRETURN_NO;

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

void XSRETURN_NV(NV nv)

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

void XSRETURN_PV(char* str)

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

XSRETURN_UNDEF;

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

void XSRETURN_UV(IV uv)

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

XSRETURN_YES;

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

void XST_mIV(int pos, IV iv)

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

void XST_mNO(int pos)

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

void XST_mNV(int pos, NV nv)

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

void XST_mPV(int pos, char* str)

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

void XST_mUNDEF(int pos)

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

void XST_mYES(int pos)

SV Flags

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

SVt_IV Integer type flag for scalars. See
svtype
.

SVt_NV Double type flag for scalars. See
svtype
.

SVt_PV Pointer type flag for scalars. See
svtype
.

SVt_PVAV Type flag for arrays. See
svtype
.

SVt_PVCV Type flag for code refs. See
svtype
.

SVt_PVHV Type flag for hashes. See
svtype
.

SVt_PVMG Type flag for blessed scalars. See
svtype
.

SV Manipulation Functions

get_sv Returns the SV of the specified Perl scalar. If
create
is set and the Perl variable does not exist then it will be created. If
create
is not set and the variable does not exist then NULL is returned.
NOTE: the perl_ form of this function is deprecated.

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

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

SV* newRV_inc(SV* sv)

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

STRLEN SvCUR(SV* sv)

SvCUR_set Set the current length of the string which is in the SV. See
SvCUR
and
SvIV_set
.

void SvCUR_set(SV* sv, STRLEN len)

SvEND Returns a pointer to the last character in the string which is in the SV. See
SvCUR
. Access the character as *(SvEND(sv)).

char* SvEND(SV* sv)

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.

char* SvGAMAGIC(SV* sv)

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

char * SvGROW(SV* sv, STRLEN len)

SvIOK Returns a U32 value indicating whether the SV contains an integer.

U32 SvIOK(SV* sv)

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

U32 SvIOKp(SV* sv)

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

bool SvIOK_notUV(SV* sv)

SvIOK_off Unsets the IV status of an SV.

void SvIOK_off(SV* sv)

SvIOK_on Tells an SV that it is an integer.

void SvIOK_on(SV* sv)

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

void SvIOK_only(SV* sv)

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

void SvIOK_only_UV(SV* sv)

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

bool SvIOK_UV(SV* sv)

SvIsCOW Returns a boolean indicating whether the SV is Copy-On-Write. (either shared hash key scalars, or full Copy On Write scalars if 5.9.0 is configured for COW)

bool SvIsCOW(SV* sv)

SvIsCOW_shared_hash Returns a boolean indicating whether the SV is Copy-On-Write shared hash key scalar.

bool SvIsCOW_shared_hash(SV* sv)

SvIV Coerces the given SV to an integer and returns it. See
SvIVx
for a version which guarantees to evaluate sv only once.

IV SvIV(SV* sv)

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

IV SvIVX(SV* sv)

SvIVx Coerces the given SV to an integer and returns it. Guarantees to evaluate
sv
only once. Only use this if
sv
is an expression with side effects, otherwise use the more efficient
SvIV
.

IV SvIVx(SV* sv)

SvIV_nomg Like
SvIV
but doesn’t process magic.

IV SvIV_nomg(SV* sv)

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

void SvIV_set(SV* sv, IV val)

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

STRLEN SvLEN(SV* sv)

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

void SvLEN_set(SV* sv, STRLEN len)

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

void SvMAGIC_set(SV* sv, MAGIC* val)

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

U32 SvNIOK(SV* sv)

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

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
.

U32 SvNOKp(SV* sv)

SvNOK_off Unsets the NV status of an SV.

void SvNOK_off(SV* sv)

SvNOK_on Tells an SV that it is a double.

void SvNOK_on(SV* sv)

SvNOK_only Tells an SV that it is a double and disables all other OK bits.

void SvNOK_only(SV* sv)

SvNV Coerce the given SV to a double and return it. See
SvNVx
for a version which guarantees to evaluate sv only once.

NV SvNV(SV* sv)

SvNVX Returns the raw value in the SV’s NV slot, without checks or conversions. Only use when you are sure SvNOK is true. See also
SvNV()
.

NV SvNVX(SV* sv)

SvNVx Coerces the given SV to a double and returns it. Guarantees to evaluate
sv
only once. Only use this if
sv
is an expression with side effects, otherwise use the more efficient
SvNV
.

NV SvNVx(SV* sv)

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

void SvNV_set(SV* sv, NV val)

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

U32 SvOK(SV* sv)

SvOOK Returns a U32 indicating whether the SvIVX is a valid offset value for the SvPVX. This hack is used internally to speed up removal of characters from the beginning of a SvPV. When SvOOK is true, then the start of the allocated string buffer is really (SvPVX - SvIVX).

U32 SvOOK(SV* sv)

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

U32 SvPOK(SV* sv)

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

U32 SvPOKp(SV* sv)

SvPOK_off Unsets the PV status of an SV.

void SvPOK_off(SV* sv)

SvPOK_on Tells an SV that it is a string.

void SvPOK_on(SV* sv)

SvPOK_only Tells an SV that it is a string and disables all other OK bits. Will also turn off the UTF-8 status.

void SvPOK_only(SV* sv)

SvPOK_only_UTF8 Tells an SV that it is a string and disables all other OK bits, and leaves the UTF-8 status as it was.

void SvPOK_only_UTF8(SV* sv)

SvPV Returns a pointer to the string in the SV, or a stringified form of the SV if the SV does not contain a string. The SV may cache the stringified version becoming
SvPOK
. Handles ’get’ magic. See also
SvPVx
for a version which guarantees to evaluate sv only once.

char* SvPV(SV* sv, STRLEN len)

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

char* SvPVbyte(SV* sv, STRLEN len)

SvPVbytex Like
SvPV
, but converts sv to byte representation first if necessary. Guarantees to evaluate sv only once; use the more efficient
SvPVbyte
otherwise.

char* SvPVbytex(SV* sv, STRLEN len)

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

char* SvPVbytex_force(SV* sv, STRLEN len)

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

char* SvPVbyte_force(SV* sv, STRLEN len)

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

char* SvPVbyte_nolen(SV* sv)

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

char* SvPVutf8(SV* sv, STRLEN len)

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

char* SvPVutf8x(SV* sv, STRLEN len)

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

char* SvPVutf8x_force(SV* sv, STRLEN len)

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

char* SvPVutf8_force(SV* sv, STRLEN len)

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

char* SvPVutf8_nolen(SV* sv)

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

char* SvPVX(SV* sv)

SvPVx A version of
SvPV
which guarantees to evaluate
sv
only once. Only use this if
sv
is an expression with side effects, otherwise use the more efficient
SvPVX
.

char* SvPVx(SV* sv, STRLEN len)

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

char* SvPV_force(SV* sv, STRLEN len)

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

char* SvPV_force_nomg(SV* sv, STRLEN len)

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

char* SvPV_nolen(SV* sv)

SvPV_nomg Like
SvPV
but doesn’t process magic.

char* SvPV_nomg(SV* sv, STRLEN len)

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

void SvPV_set(SV* sv, char* val)

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

U32 SvREFCNT(SV* sv)

SvREFCNT_dec Decrements the reference count of the given SV.

void SvREFCNT_dec(SV* sv)

SvREFCNT_inc Increments the reference count of the given SV.
All of the following SvREFCNT_inc* macros are optimized versions of SvREFCNT_inc, and can be replaced with SvREFCNT_inc.

SV* SvREFCNT_inc(SV* sv)

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

SV* SvREFCNT_inc_NN(SV* sv)

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

SV* SvREFCNT_inc_simple(SV* sv)

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

SV* SvREFCNT_inc_simple_NN(SV* sv)

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

void SvREFCNT_inc_simple_void(SV* sv)

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

void SvREFCNT_inc_simple_void_NN(SV* sv)

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

void SvREFCNT_inc_void(SV* sv)

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

void SvREFCNT_inc_void_NN(SV* sv)

SvROK Tests if the SV is an RV.

U32 SvROK(SV* sv)

SvROK_off Unsets the RV status of an SV.

void SvROK_off(SV* sv)

SvROK_on Tells an SV that it is an RV.

void SvROK_on(SV* sv)

SvRV Dereferences an RV to return the SV.

SV* SvRV(SV* sv)

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

void SvRV_set(SV* sv, SV* val)

SvSTASH Returns the stash of the SV.

HV* SvSTASH(SV* sv)

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

void SvSTASH_set(SV* sv, HV* val)

SvTAINT Taints an SV if tainting is enabled.

void SvTAINT(SV* sv)

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

bool SvTAINTED(SV* sv)

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

void SvTAINTED_off(SV* sv)

SvTAINTED_on Marks an SV as tainted if tainting is enabled.

void SvTAINTED_on(SV* sv)

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

bool SvTRUE(SV* sv)

SvTYPE Returns the type of the SV. See
svtype
.

svtype SvTYPE(SV* sv)

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

bool SvUOK(SV* sv)

SvUPGRADE Used to upgrade an SV to a more complex form. Uses
sv_upgrade
to perform the upgrade if necessary. See
svtype
.

void SvUPGRADE(SV* sv, svtype type)

SvUTF8 Returns a U32 value indicating whether the SV contains UTF-8 encoded data. Call this after SvPV() in case any call to string overloading updates the internal flag.

U32 SvUTF8(SV* sv)

SvUTF8_off Unsets the UTF-8 status of an SV.

void SvUTF8_off(SV *sv)

SvUTF8_on Turn on the UTF-8 status of an SV (the data is not changed, just the flag). Do not use frivolously.

void SvUTF8_on(SV *sv)

SvUV Coerces the given SV to an unsigned integer and returns it. See
SvUVx
for a version which guarantees to evaluate sv only once.

UV SvUV(SV* sv)

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

UV SvUVX(SV* sv)

SvUVx Coerces the given SV to an unsigned integer and returns it. Guarantees to
sv
only once. Only use this if
sv
is an expression with side effects, otherwise use the more efficient
SvUV
.

UV SvUVx(SV* sv)

SvUV_nomg Like
SvUV
but doesn’t process magic.

UV SvUV_nomg(SV* sv)

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

void SvUV_set(SV* sv, UV val)

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_catsv_nomg Like
sv_catsv
but doesn’t process magic.

void sv_catsv_nomg(SV* dsv, SV* ssv)

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

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

sv_does 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, const char* name)

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

void sv_report_used()

sv_setsv_nomg Like
sv_setsv
but doesn’t process magic.

void sv_setsv_nomg(SV* dsv, SV* ssv)

SV-Body Allocation

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

I32 looks_like_number(SV* sv)

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

SV* newRV_noinc(SV* sv)

newSV Creates a new SV. A non-zero
len
parameter indicates the number of bytes of preallocated string space the SV should have. An extra byte for a trailing NUL is also reserved. (SvPOK is not set for the SV even if string space is allocated.) The reference count for the new SV is set to 1.
In 5.9.3, newSV() replaces the older NEWSV() API, and drops the first parameter, x, a debug aid which allowed callers to identify themselves. This aid has been superseded by a new build option, PERL_MEM_LOG (see PERL_MEM_LOG in perlhack). The older API is still there for use in XS modules supporting older perls.

SV* newSV(STRLEN len)

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

SV* newSVhek(const HEK *hek)

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

SV* newSViv(IV i)

newSVnv Creates a new SV and copies a floating point value into it. The reference count for the SV is set to 1.

SV* newSVnv(NV n)

newSVpv Creates a new SV and copies a string into it. The reference count for the SV is set to 1. If
len
is zero, Perl will compute the length using strlen(). For efficiency, consider using
newSVpvn
instead.

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

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

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

newSVpvn Creates a new SV and copies a string into it. The reference count for the SV is set to 1. Note that if
len
is zero, Perl will create a zero length string. You are responsible for ensuring that the source string is at least
len
bytes long. If the
s
argument is NULL the new SV will be undefined.

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

newSVpvn_share Creates a new SV with its SvPVX_const pointing to a shared string in the string table. If the string does not already exist in the table, it is created first. Turns on READONLY and FAKE. If the
hash
parameter is non-zero, that value is used; otherwise the hash is computed. The string’s hash can be later be retrieved from the SV with the
SvSHARED_HASH()
macro. The idea here is that as the string table is used for shared hash keys these strings will have SvPVX_const == HeKEY and hash lookup will avoid string compare.

SV* newSVpvn_share(const char* s, I32 len, U32 hash)

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

SV* newSVpvs(const char* s)

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

SV* newSVpvs_share(const char* s)

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

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

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

SV* newSVsv(SV* old)

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

SV* newSVuv(UV u)

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

SV* newSV_type(svtype type)

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

bool sv_2bool(SV* sv)

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

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

sv_2io Using various gambits, try to get an IO from an SV: the IO slot if its a GV; or the recursive result if we’re an RV; or the IO slot of the symbol named after the PV if we’re a string.

IO* sv_2io(SV* sv)

sv_2iv_flags Return the integer value of an SV, doing any necessary string conversion. If flags includes SV_GMAGIC, does an mg_get() first. Normally used via the
SvIV(sv)
and
SvIVx(sv)
macros.

IV sv_2iv_flags(SV* sv, I32 flags)

sv_2mortal Marks an existing SV as mortal. The SV will be destroyed soon, either by an explicit call to FREETMPS, or by an implicit call at places such as statement boundaries. SvTEMP() is turned on which means that the SV’s string buffer can be stolen if this SV is copied. See also
sv_newmortal
and
sv_mortalcopy
.

SV* sv_2mortal(SV* sv)

sv_2nv Return the num value of an SV, doing any necessary string or integer conversion, magic etc. Normally used via the
SvNV(sv)
and
SvNVx(sv)
macros.

NV sv_2nv(SV* sv)

sv_2pvbyte Return a pointer to the byte-encoded representation of the SV, and set *lp to its length. May cause the SV to be downgraded from UTF-8 as a side-effect.
Usually accessed via the
SvPVbyte
macro.

char* sv_2pvbyte(SV* sv, STRLEN* lp)

sv_2pvutf8 Return a pointer to the UTF-8-encoded representation of the SV, and set *lp to its length. May cause the SV to be upgraded to UTF-8 as a side-effect.
Usually accessed via the
SvPVutf8
macro.

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

sv_2pv_flags Returns a pointer to the string value of an SV, and sets *lp to its length. If flags includes SV_GMAGIC, does an mg_get() first. Coerces sv to a string if necessary. Normally invoked via the
SvPV_flags
macro.
sv_2pv()
and
sv_2pv_nomg
usually end up here too.

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

sv_2uv_flags Return the unsigned integer value of an SV, doing any necessary string conversion. If flags includes SV_GMAGIC, does an mg_get() first. Normally used via the
SvUV(sv)
and
SvUVx(sv)
macros.

UV sv_2uv_flags(SV* sv, I32 flags)

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

int sv_backoff(SV* sv)

sv_bless Blesses an SV into a specified package. The SV must be an RV. The package must be designated by its stash (see
gv_stashpv()
). The reference count of the SV is unaffected.

SV* sv_bless(SV* sv, HV* stash)

sv_catpv Concatenates the string onto the end of the string which is in the SV. If the SV has the UTF-8 status set, then the bytes appended should be valid UTF-8. Handles ’get’ magic, but not ’set’ magic. See
sv_catpv_mg
.

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

sv_catpvf Processes its arguments like
sprintf
and appends the formatted output to an SV. If the appended data contains wide characters (including, but not limited to, SVs with a UTF-8 PV formatted with
%s
, and characters >255 formatted with
%c
), the original SV might get upgraded to UTF-8. Handles ’get’ magic, but not ’set’ magic. See
sv_catpvf_mg
. If the original SV was UTF-8, the pattern should be valid UTF-8; if the original SV was bytes, the pattern should be too.

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

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

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

sv_catpvn Concatenates the string onto the end of the string which is in the SV. The
len
indicates number of bytes to copy. If the SV has the UTF-8 status set, then the bytes appended should be valid UTF-8. Handles ’get’ magic, but not ’set’ magic. See
sv_catpvn_mg
.

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

sv_catpvn_flags Concatenates the string onto the end of the string which is in the SV. The
len
indicates number of bytes to copy. If the SV has the UTF-8 status set, then the bytes appended should be valid UTF-8. If
flags
has
SV_GMAGIC
bit set, will
mg_get
on
dsv
if appropriate, else not.
sv_catpvn
and
sv_catpvn_nomg
are implemented in terms of this function.

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

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

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

sv_catpv_mg Like
sv_catpv
, but also handles ’set’ magic.

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

sv_catsv Concatenates the string from SV
ssv
onto the end of the string in SV
dsv
. Modifies
dsv
but not
ssv
. Handles ’get’ magic, but not ’set’ magic. See
sv_catsv_mg
.

void sv_catsv(SV* dsv, SV* ssv)

sv_catsv_flags Concatenates the string from SV
ssv
onto the end of the string in SV
dsv
. Modifies
dsv
but not
ssv
. If
flags
has
SV_GMAGIC
bit set, will
mg_get
on the SVs if appropriate, else not.
sv_catsv
and
sv_catsv_nomg
are implemented in terms of this function.

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

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

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

sv_clear Clear an SV: call any destructors, free up any memory used by the body, and free the body itself. The SV’s head is not freed, although its type is set to all 1’s so that it won’t inadvertently be assumed to be live during global destruction etc. This function should only be called when REFCNT is zero. Most of the time you’ll want to call
sv_free()
(or its macro wrapper
SvREFCNT_dec
) instead.

void sv_clear(SV* sv)

sv_cmp Compares the strings in two SVs. Returns -1, 0, or 1 indicating whether the string in
sv1
is less than, equal to, or greater than the string in
sv2
. Is UTF-8 and ’use bytes’ aware, handles get magic, and will coerce its args to strings if necessary. See also
sv_cmp_locale
.

I32 sv_cmp(SV* sv1, SV* sv2)

sv_cmp_locale Compares the strings in two SVs in a locale-aware manner. Is UTF-8 and ’use bytes’ aware, handles get magic, and will coerce its args to strings if necessary. See also
sv_cmp_locale
. See also
sv_cmp
.

I32 sv_cmp_locale(SV* sv1, SV* sv2)

sv_collxfrm Add Collate Transform magic to an SV if it doesn’t already have it.
Any scalar variable may carry PERL_MAGIC_collxfrm magic that contains the scalar data of the variable, but transformed to such a format that a normal memory comparison can be used to compare the data according to the locale settings.

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

sv_copypv Copies a stringified representation of the source SV into the destination SV. Automatically performs any necessary mg_get and coercion of numeric values into strings. Guaranteed to preserve UTF8 flag even from overloaded objects. Similar in nature to sv_2pv[_flags] but operates directly on an SV instead of just the string. Mostly uses sv_2pv_flags to do its work, except when that would lose the UTF-8’ness of the PV.

void sv_copypv(SV* dsv, SV* ssv)

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

void sv_dec(SV* sv)

sv_eq Returns a boolean indicating whether the strings in the two SVs are identical. Is UTF-8 and ’use bytes’ aware, handles get magic, and will coerce its args to strings if necessary.

I32 sv_eq(SV* sv1, SV* sv2)

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

void sv_force_normal_flags(SV *sv, U32 flags)

sv_free Decrement an SV’s reference count, and if it drops to zero, call
sv_clear
to invoke destructors and free up any memory used by the body; finally, deallocate the SV’s head itself. Normally called via a wrapper macro
SvREFCNT_dec
.

void sv_free(SV* sv)

sv_gets Get a line from the filehandle and store it into the SV, optionally appending to the currently-stored string.

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

sv_grow Expands the character buffer in the SV. If necessary, uses
sv_unref
and upgrades the SV to
SVt_PV
. Returns a pointer to the character buffer. Use the
SvGROW
wrapper instead.

char* sv_grow(SV* sv, STRLEN newlen)

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

void sv_inc(SV* sv)

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

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

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

int sv_isa(SV* sv, const char* name)

sv_isobject Returns a boolean indicating whether the SV is an RV pointing to a blessed object. If the SV is not an RV, or if the object is not blessed, then this will return false.

int sv_isobject(SV* sv)

sv_len Returns the length of the string in the SV. Handles magic and type coercion. See also
SvCUR
, which gives raw access to the xpv_cur slot.

STRLEN sv_len(SV* sv)

sv_len_utf8 Returns the number of characters in the string in an SV, counting wide UTF-8 bytes as a single character. Handles magic and type coercion.

STRLEN sv_len_utf8(SV* sv)

sv_magic Adds magic to an SV. First upgrades
sv
to type
SVt_PVMG
if necessary, then adds a new magic item of type
how
to the head of the magic list.
See
sv_magicext
(which
sv_magic
now calls) for a description of the handling of the
name
and
namlen
arguments.
You need to use
sv_magicext
to add magic to SvREADONLY SVs and also to add more than one instance of the same ’how’.

void sv_magic(SV* sv, SV* obj, int how, const char* name, I32 namlen)

sv_magicext Adds magic to an SV, upgrading it if necessary. Applies the supplied vtable and returns a pointer to the magic added.
Note that
sv_magicext
will allow things that
sv_magic
will not. In particular, you can add magic to SvREADONLY SVs, and add more than one instance of the same ’how’.
If
namlen
is greater than zero then a
savepvn
copy of
name
is stored, if
namlen
is zero then
name
is stored as-is and - as another special case - if
(name && namlen == HEf_SVKEY)
then
name
is assumed to contain an
SV*
and is stored as-is with its REFCNT incremented.
(This is now used as a subroutine by
sv_magic
.)

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

sv_mortalcopy Creates a new SV which is a copy of the original SV (using
sv_setsv
). The new SV is marked as mortal. It will be destroyed soon, either by an explicit call to FREETMPS, or by an implicit call at places such as statement boundaries. See also
sv_newmortal
and
sv_2mortal
.

SV* sv_mortalcopy(SV* oldsv)

sv_newmortal Creates a new null SV which is mortal. The reference count of the SV is set to 1. It will be destroyed soon, either by an explicit call to FREETMPS, or by an implicit call at places such as statement boundaries. See also
sv_mortalcopy
and
sv_2mortal
.

SV* sv_newmortal()

sv_newref Increment an SV’s reference count. Use the
SvREFCNT_inc()
wrapper instead.

SV* sv_newref(SV* sv)

sv_pos_b2u Converts the value pointed to by offsetp from a count of bytes from the start of the string, to a count of the equivalent number of UTF-8 chars. Handles magic and type coercion.

void sv_pos_b2u(SV* sv, I32* offsetp)

sv_pos_u2b Converts the value pointed to by offsetp from a count of UTF-8 chars from the start of the string, to a count of the equivalent number of bytes; if lenp is non-zero, it does the same to lenp, but this time starting from the offset, rather than from the start of the string. Handles magic and type coercion.

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

sv_pvbyten_force The backend for the
SvPVbytex_force
macro. Always use the macro instead.

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

sv_pvn_force Get a sensible string out of the SV somehow. A private implementation of the
SvPV_force
macro for compilers which can’t cope with complex macro expressions. Always use the macro instead.

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

sv_pvn_force_flags Get a sensible string out of the SV somehow. If
flags
has
SV_GMAGIC
bit set, will
mg_get
on
sv
if appropriate, else not.
sv_pvn_force
and
sv_pvn_force_nomg
are implemented in terms of this function. You normally want to use the various wrapper macros instead: see
SvPV_force
and
SvPV_force_nomg

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

sv_pvutf8n_force The backend for the
SvPVutf8x_force
macro. Always use the macro instead.

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

sv_reftype Returns a string describing what the SV is a reference to.

const char* sv_reftype(const SV* sv, int ob)

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

void sv_replace(SV* sv, SV* nsv)

sv_reset Underlying implementation for the
reset
Perl function. Note that the perl-level function is vaguely deprecated.

void sv_reset(const char* s, HV* stash)

sv_rvweaken Weaken a reference: set the
SvWEAKREF
flag on this RV; give the referred-to SV
PERL_MAGIC_backref
magic if it hasn’t already; and push a back-reference to this RV onto the array of backreferences associated with that magic. If the RV is magical, set magic will be called after the RV is cleared.

SV* sv_rvweaken(SV *sv)

sv_setiv Copies an integer into the given SV, upgrading first if necessary. Does not handle ’set’ magic. See also
sv_setiv_mg
.

void sv_setiv(SV* sv, IV num)

sv_setiv_mg Like
sv_setiv
, but also handles ’set’ magic.

void sv_setiv_mg(SV *sv, IV i)

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

void sv_setnv(SV* sv, NV num)

sv_setnv_mg Like
sv_setnv
, but also handles ’set’ magic.

void sv_setnv_mg(SV *sv, NV num)

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

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

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

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

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

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

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

void sv_setpviv(SV* sv, IV num)

sv_setpviv_mg Like
sv_setpviv
, but also handles ’set’ magic.

void sv_setpviv_mg(SV *sv, IV iv)

sv_setpvn Copies a string into an SV. The
len
parameter indicates the number of bytes to be copied. If the
ptr
argument is NULL the SV will become undefined. Does not handle ’set’ magic. See
sv_setpvn_mg
.

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

sv_setpvn_mg Like
sv_setpvn
, but also handles ’set’ magic.

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

sv_setpvs Like
sv_setpvn
, but takes a literal string instead of a string/length pair.

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

sv_setpv_mg Like
sv_setpv
, but also handles ’set’ magic.

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

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

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

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

SV* sv_setref_nv(SV* rv, const char* classname, NV nv)

sv_setref_pv Copies a pointer into a new SV, optionally blessing the SV. The
rv
argument will be upgraded to an RV. That RV will be modified to point to the new SV. If the
pv
argument is NULL then
PL_sv_undef
will be placed into the SV. The
classname
argument indicates the package for the blessing. Set
classname
to
NULL
to avoid the blessing. The new SV will have a reference count of 1, and the RV will be returned.
Do not use with other Perl types such as HV, AV, SV, CV, because those objects will become corrupted by the pointer copy process.
Note that
sv_setref_pvn
copies the string while this copies the pointer.

SV* sv_setref_pv(SV* rv, const char* classname, void* pv)

sv_setref_pvn Copies a string into a new SV, optionally blessing the SV. The length of the string must be specified with
n
. The
rv
argument will be upgraded to an RV. That RV will be modified to point to the new SV. The
classname
argument 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* rv, const char* classname, const char* pv, STRLEN n)

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

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

sv_setsv Copies the contents of the source SV
ssv
into the destination SV
dsv
. The source SV may be destroyed if it is mortal, so don’t use this function if the source SV needs to be reused. Does not handle ’set’ magic. Loosely speaking, it performs a copy-by-value, obliterating any previous content of the destination.
You probably want to use one of the assortment of wrappers, such as
SvSetSV
,
SvSetSV_nosteal
,
SvSetMagicSV
and
SvSetMagicSV_nosteal
.

void sv_setsv(SV* dsv, SV* ssv)

sv_setsv_flags Copies the contents of the source SV
ssv
into the destination SV
dsv
. The source SV may be destroyed if it is mortal, so don’t use this function if the source SV needs to be reused. Does not handle ’set’ magic. Loosely speaking, it performs a copy-by-value, obliterating any previous content of the destination. If the
flags
parameter has the
SV_GMAGIC
bit set, will
mg_get
on
ssv
if appropriate, else not. If the
flags
parameter has the
NOSTEAL
bit set then the buffers of temps will not be stolen. <sv_setsv> and
sv_setsv_nomg
are implemented in terms of this function.
You probably want to use one of the assortment of wrappers, such as
SvSetSV
,
SvSetSV_nosteal
,
SvSetMagicSV
and
SvSetMagicSV_nosteal
.
This is the primary function for copying scalars, and most other copy-ish functions and macros use this underneath.

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

sv_setsv_mg Like
sv_setsv
, but also handles ’set’ magic.

void sv_setsv_mg(SV *dstr, SV *sstr)

sv_setuv Copies an unsigned integer into the given SV, upgrading first if necessary. Does not handle ’set’ magic. See also
sv_setuv_mg
.

void sv_setuv(SV* sv, UV num)

sv_setuv_mg Like
sv_setuv
, but also handles ’set’ magic.

void sv_setuv_mg(SV *sv, UV u)

sv_tainted Test an SV for taintedness. Use
SvTAINTED
instead. bool sv_tainted(SV* sv)

sv_true Returns true if the SV has a true value by Perl’s rules. Use the
SvTRUE
macro instead, which may call
sv_true()
or may instead use an in-line version.

I32 sv_true(SV *sv)

sv_unmagic Removes all magic of type
type
from an SV.

int sv_unmagic(SV* sv, int type)

sv_unref_flags Unsets the RV status of the SV, and decrements the reference count of whatever was being referenced by the RV. This can almost be thought of as a reversal of
newSVrv
. The
cflags
argument can contain
SV_IMMEDIATE_UNREF
to force the reference count to be decremented (otherwise the decrementing is conditional on the reference count being different from one or the reference being a readonly SV). See
SvROK_off
.

void sv_unref_flags(SV* sv, U32 flags)

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

sv_upgrade Upgrade an SV to a more complex form. Generally adds a new body type to the SV, then copies across as much information as possible from the old body. You generally want to use the
SvUPGRADE
macro wrapper. See also
svtype
.

void sv_upgrade(SV* sv, svtype new_type)

sv_usepvn_flags Tells an SV to use
ptr
to find its string value. Normally the string is stored inside the SV but sv_usepvn allows the SV to use an outside string. The
ptr
should point to memory that was allocated by
malloc
. The string length,
len
, must be supplied. By default this function will realloc (i.e. move) the memory pointed to by
ptr
, so that pointer should not be freed or used by the programmer after giving it to sv_usepvn, and neither should any pointers from behind that pointer (e.g. ptr + 1) be used.
If
flags
& SV_SMAGIC is true, will call SvSETMAGIC. If
flags
& SV_HAS_TRAILING_NUL is true, then
ptr[len]
must be NUL, and the realloc will be skipped. (i.e. the buffer is actually at least 1 byte longer than
len
, and already meets the requirements for storing in
SvPVX
)

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

sv_utf8_decode If the PV of the SV is an octet sequence in UTF-8 and contains a multiple-byte character, the
SvUTF8
flag is turned on so that it looks like a character. If the PV contains only single-byte characters, the
SvUTF8
flag stays being off. Scans PV for validity and returns false if the PV is invalid UTF-8.
NOTE: this function is experimental and may change or be removed without notice.

bool sv_utf8_decode(SV *sv)

sv_utf8_downgrade Attempts to convert the PV of an SV from characters to bytes. If the PV contains a character beyond byte, this conversion will fail; in this case, either returns false or, if
fail_ok
is not true, croaks.
This is not as a general purpose Unicode to byte encoding interface: use the Encode extension for that.
NOTE: this function is experimental and may change or be removed without notice.

bool sv_utf8_downgrade(SV *sv, bool fail_ok)

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

void sv_utf8_encode(SV *sv)

sv_utf8_upgrade Converts the PV of an SV to its UTF-8-encoded form. Forces the SV to string form if it is not already. Always sets the SvUTF8 flag to avoid future validity checks even if all the bytes have hibit clear.
This is not as a general purpose byte encoding to Unicode interface: use the Encode extension for that.

STRLEN sv_utf8_upgrade(SV *sv)

sv_utf8_upgrade_flags Converts the PV of an SV to its UTF-8-encoded form. Forces the SV to string form if it is not already. Always sets the SvUTF8 flag to avoid future validity checks even if all the bytes have hibit clear. If
flags
has
SV_GMAGIC
bit set, will
mg_get
on
sv
if appropriate, else not.
sv_utf8_upgrade
and
sv_utf8_upgrade_nomg
are implemented in terms of this function.
This is not as a general purpose byte encoding to Unicode interface: use the Encode extension for that.

STRLEN sv_utf8_upgrade_flags(SV *sv, I32 flags)

sv_vcatpvf Processes its arguments like
vsprintf
and appends the formatted output to an SV. Does not handle ’set’ magic. See
sv_vcatpvf_mg
.
Usually used via its frontend
sv_catpvf
.

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

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

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

sv_vcatpvf_mg Like
sv_vcatpvf
, but also handles ’set’ magic.
Usually used via its frontend
sv_catpvf_mg
.

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

sv_vsetpvf Works like
sv_vcatpvf
but copies the text into the SV instead of appending it. Does not handle ’set’ magic. See
sv_vsetpvf_mg
.
Usually used via its frontend
sv_setpvf
.

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

sv_vsetpvfn Works like
sv_vcatpvfn
but copies the text into the SV instead of appending it.
Usually used via one of its frontends
sv_vsetpvf
and
sv_vsetpvf_mg
.

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

sv_vsetpvf_mg Like
sv_vsetpvf
, but also handles ’set’ magic.
Usually used via its frontend
sv_setpvf_mg
.

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

Unicode Support

bytes_from_utf8 Converts a string
s
of length
len
from UTF-8 into byte encoding. Unlike
utf8_to_bytes
but like
bytes_to_utf8
, returns a pointer to the newly-created string, and updates
len
to contain the new length. Returns the original string if no conversion occurs,
len
is unchanged. Do nothing if
is_utf8
points to 0. Sets
is_utf8
to 0 if
s
is converted or contains all 7bit characters.
NOTE: this function is experimental and may change or be removed without notice.

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

bytes_to_utf8 Converts a string
s
of length
len
from ASCII into UTF-8 encoding. Returns a pointer to the newly-created string, and sets
len
to reflect the new length.
If you want to convert to UTF-8 from other encodings than ASCII, see sv_recode_to_utf8().
NOTE: this function is experimental and may change or be removed without notice.

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

ibcmp_utf8 Return true if the strings s1 and s2 differ case-insensitively, false if not (if they are equal case-insensitively). If u1 is true, the string s1 is assumed to be in UTF-8-encoded Unicode. If u2 is true, the string s2 is assumed to be in UTF-8-encoded Unicode. If u1 or u2 are false, the respective string is assumed to be in native 8-bit encoding.
If the pe1 and pe2 are non-NULL, the scanning pointers will be copied in there (they will point at the beginning of the next character). If the pointers behind pe1 or pe2 are non-NULL, they are the end pointers beyond which scanning will not continue under any circumstances. If the byte lengths l1 and l2 are non-zero, s1+l1 and s2+l2 will be used as goal end pointers that will also stop the scan, and which qualify towards defining a successful match: all the scans that define an explicit length must reach their goal pointers for a match to succeed).
For case-insensitiveness, the casefolding of Unicode is used instead of upper/lowercasing both the characters, see http://www.unicode.org/unicode/reports/tr21/ (Case Mappings).

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

is_utf8_char Tests if some arbitrary number of bytes begins in a valid UTF-8 character. Note that an INVARIANT (i.e. ASCII) character is a valid UTF-8 character. The actual number of bytes in the UTF-8 character will be returned if it is valid, otherwise 0.

STRLEN is_utf8_char(const U8 *p)

is_utf8_string Returns true if first
len
bytes of the given string form a valid UTF-8 string, false otherwise. Note that ’a valid UTF-8 string’ does not mean ’a string that contains code points above 0x7F encoded in UTF-8’ because a valid ASCII string is a valid UTF-8 string.
See also is_utf8_string_loclen() and is_utf8_string_loc().

bool is_utf8_string(const U8 *s, STRLEN len)

is_utf8_string_loc Like is_utf8_string() but stores the location of the failure (in the case of utf8ness failure) or the location s+len (in the case of utf8ness success) in the
ep
.
See also is_utf8_string_loclen() and is_utf8_string().

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

is_utf8_string_loclen Like is_utf8_string() but stores the location of the failure (in the case of utf8ness failure) or the location s+len (in the case of utf8ness success) in the
ep
, and the number of UTF-8 encoded characters in the
el
.
See also is_utf8_string_loc() and is_utf8_string().

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

pv_uni_display Build to the scalar dsv a displayable version of the string spv, length len, the displayable version being at most pvlim bytes long (if longer, the rest is truncated and ... will be appended).
The flags argument can have UNI_DISPLAY_ISPRINT set to display isPRINT()able characters as themselves, UNI_DISPLAY_BACKSLASH to display the \\[nrfta\\] as the backslashed versions (like ’\n’) (UNI_DISPLAY_BACKSLASH is preferred over UNI_DISPLAY_ISPRINT for \\). UNI_DISPLAY_QQ (and its alias UNI_DISPLAY_REGEX) have both UNI_DISPLAY_BACKSLASH and UNI_DISPLAY_ISPRINT turned on.
The pointer to the PV of the dsv is returned.

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

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

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

sv_recode_to_utf8 The encoding is assumed to be an Encode object, on entry the PV of the sv is assumed to be octets in that encoding, and the sv will be converted into Unicode (and UTF-8).
If the sv already is UTF-8 (or if it is not POK), or if the encoding is not a reference, nothing is done to the sv. If the encoding is not an
Encode::XS
Encoding object, bad things will happen. (See lib/encoding.pm and Encode).
The PV of the sv is returned.

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

sv_uni_display Build to the scalar dsv a displayable version of the scalar sv, the displayable version being at most pvlim bytes long (if longer, the rest is truncated and ... will be appended).
The flags argument is as in pv_uni_display().
The pointer to the PV of the dsv is returned.

char* sv_uni_display(SV *dsv, SV *ssv, STRLEN pvlim, UV flags)

to_utf8_case The p contains the pointer to the UTF-8 string encoding the character that is being converted.
The ustrp is a pointer to the character buffer to put the conversion result to. The lenp is a pointer to the length of the result.
The swashp is a pointer to the swash to use.
Both the special and normal mappings are stored lib/unicore/To/Foo.pl, and loaded by SWASHNEW, using lib/utf8_heavy.pl. The special (usually, but not always, a multicharacter mapping), is tried first.
The special is a string like utf8::ToSpecLower, which means the hash
%utf8::ToSpecLower
. The access to the hash is through Perl_to_utf8_case().
The normal is a string like ToLower which means the swash
%utf8::ToLower
.

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

to_utf8_fold Convert the UTF-8 encoded character at p to its foldcase version and store that in UTF-8 in ustrp and its length in bytes in lenp. Note that the ustrp needs to be at least UTF8_MAXBYTES_CASE+1 bytes since the foldcase version may be longer than the original character (up to three characters).
The first character of the foldcased version is returned (but note, as explained above, that there may be more.)

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

to_utf8_lower Convert the UTF-8 encoded character at p to its lowercase version and store that in UTF-8 in ustrp and its length in bytes in lenp. Note that the ustrp needs to be at least UTF8_MAXBYTES_CASE+1 bytes since the lowercase version may be longer than the original character.
The first character of the lowercased version is returned (but note, as explained above, that there may be more.)

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

to_utf8_title Convert the UTF-8 encoded character at p to its titlecase version and store that in UTF-8 in ustrp and its length in bytes in lenp. Note that the ustrp needs to be at least UTF8_MAXBYTES_CASE+1 bytes since the titlecase version may be longer than the original character.
The first character of the titlecased version is returned (but note, as explained above, that there may be more.)

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

to_utf8_upper Convert the UTF-8 encoded character at p to its uppercase version and store that in UTF-8 in ustrp and its length in bytes in lenp. Note that the ustrp needs to be at least UTF8_MAXBYTES_CASE+1 bytes since the uppercase version may be longer than the original character.
The first character of the uppercased version is returned (but note, as explained above, that there may be more.)

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

utf8n_to_uvchr flags
Returns the native character value of the first character in the string
s
which is assumed to be in UTF-8 encoding;
retlen
will be set to the length, in bytes, of that character.
Allows length and flags to be passed to low level routine.

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

utf8n_to_uvuni Bottom level UTF-8 decode routine. Returns the Unicode code point value of the first character in the string
s
which is assumed to be in UTF-8 encoding and no longer than
curlen
;
retlen
will be set to the length, in bytes, of that character.
If
s
does not point to a well-formed UTF-8 character, the behaviour is dependent on the value of
flags
: if it contains UTF8_CHECK_ONLY, it is assumed that the caller will raise a warning, and this function will silently just set
retlen
to
-1
and return zero. If the
flags
does not contain UTF8_CHECK_ONLY, warnings about malformations will be given,
retlen
will be set to the expected length of the UTF-8 character in bytes, and zero will be returned.
The
flags
can also contain various flags to allow deviations from the strict UTF-8 encoding (see utf8.h).
Most code should use utf8_to_uvchr() rather than call this directly.

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

utf8_distance Returns the number of UTF-8 characters between the UTF-8 pointers
a
and
b
.
WARNING: use only if you *know* that the pointers point inside the same UTF-8 buffer.

IV utf8_distance(const U8 *a, const U8 *b)

utf8_hop Return the UTF-8 pointer
s
displaced by
off
characters, either forward or backward.
WARNING: do not use the following unless you *know*
off
is within the UTF-8 data pointed to by
s
*and* that on entry
s
is aligned on the first byte of character or just after the last byte of a character.

U8* utf8_hop(const U8 *s, I32 off)

utf8_length Return the length of the UTF-8 char encoded string
s
in characters. Stops at
e
(inclusive). If
e < s
or if the scan would end up past
e
, croaks.

STRLEN utf8_length(const U8* s, const U8 *e)

utf8_to_bytes Converts a string
s
of length
len
from UTF-8 into byte encoding. Unlike
bytes_to_utf8
, this over-writes the original string, and updates len to contain the new length. Returns zero on failure, setting
len
to -1.
If you need a copy of the string, see
bytes_from_utf8
.
NOTE: this function is experimental and may change or be removed without notice.

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

utf8_to_uvchr Returns the native character value of the first character in the string
s
which is assumed to be in UTF-8 encoding;
retlen
will be set to the length, in bytes, of that character.
If
s
does not point to a well-formed UTF-8 character, zero is returned and retlen is set, if possible, to -1.

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

utf8_to_uvuni Returns the Unicode code point of the first character in the string
s
which is assumed to be in UTF-8 encoding;
retlen
will be set to the length, in bytes, of that character.
This function should only be used when returned UV is considered an index into the Unicode semantic tables (e.g. swashes).
If
s
does not point to a well-formed UTF-8 character, zero is returned and retlen is set, if possible, to -1.

UV utf8_to_uvuni(const U8 *s, STRLEN *retlen)

uvchr_to_utf8 Adds the UTF-8 representation of the Native codepoint
uv
to the end of the string
d
;
d
should be have at least
UTF8_MAXBYTES+1
free bytes available. The return value is the pointer to the byte after the end of the new character. In other words,

d = uvchr_to_utf8(d, uv);

is the recommended wide native character-aware way of saying

*(d++) = uv; U8* uvchr_to_utf8(U8 *d, UV uv)

uvuni_to_utf8_flags Adds the UTF-8 representation of the Unicode codepoint
uv
to the end of the string
d
;
d
should be have at least
UTF8_MAXBYTES+1
free bytes available. The return value is the pointer to the byte after the end of the new character. In other words,

d = uvuni_to_utf8_flags(d, uv, flags);

or, in most cases,

d = uvuni_to_utf8(d, uv);

(which is equivalent to)

d = uvuni_to_utf8_flags(d, uv, 0);

is the recommended Unicode-aware way of saying

*(d++) = uv; U8* uvuni_to_utf8_flags(U8 *d, UV uv, UV flags)

Variables created by \f(CWxsubpp\fP and \f(CWxsubpp\fP 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 the
padoff_du
variable for an XSUB that wishes to use
UNDERBAR
.

dUNDERBAR;

dXSARGS Sets up stack and mark pointers for an XSUB, calling dSP and dMARK. Sets up the
ax
and
items
variables by calling
dAX
and
dITEMS
. This is usually handled automatically by
xsubpp
.

dXSARGS;

dXSI32 Sets up the
ix
variable for an XSUB which has aliases. This is usually handled automatically by
xsubpp
.

dXSI32;

items Variable which is setup by
xsubpp
to indicate the number of items on the stack. See Variable-length Parameter Lists in perlxs.

I32 items

ix Variable which is setup by
xsubpp
to indicate which of an XSUB’s aliases was used to invoke it. See The ALIAS: Keyword in perlxs.

I32 ix

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

RETVAL Variable which is setup by
xsubpp
to hold the return value for an XSUB. This is always the proper type for the XSUB. See The RETVAL Variable in perlxs.

(whatever) RETVAL

ST Used to access elements on the XSUB’s stack.

SV* ST(int ix)

THIS Variable which is setup by
xsubpp
to designate the object in a C++ XSUB. This is always the proper type for the C++ object. See
CLASS
and Using XS With C++ in perlxs.

(whatever) THIS

UNDERBAR The SV* corresponding to the
$_
variable. Works even if there is a lexical
$_
in scope.

XS Macro to declare an XSUB and its C parameter list. This is handled by
xsubpp
.

XS_VERSION The version identifier for an XS module. This is usually handled automatically by
ExtUtils::MakeMaker
. See
XS_VERSION_BOOTCHECK
.

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

XS_VERSION_BOOTCHECK;

Warning and Dieing

croak This is the XSUB-writer’s interface to Perl’s
die
function. Normally call this function the same way you call the C
printf
function. Calling
croak
returns control directly to Perl, sidestepping the normal C order of execution. See
warn
.
If you want to throw an exception object, assign the object to
$@
and then pass
NULL
to croak():

errsv = get_sv("@", TRUE); sv_setsv(errsv, exception_object); croak(NULL); void croak(const char* pat, ...)

warn This is the XSUB-writer’s interface to Perl’s
warn
function. Call this function the same way you call the C
printf
function. See
croak
.

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

AUTHORS

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

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

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

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