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 the perlcall manpage.

G_DISCARD

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

G_EVAL

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

G_NOARGS

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

G_SCALAR

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

G_VOID

Used to indicate void context. See GIMME_V and the perlcall manpage.

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 the perlguts manpage for more information on how to use this function on tied arrays.

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

av_fill

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

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

        void    av_fill(AV* ar, I32 fill)

av_len

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

        I32     av_len(AV* ar)

av_make

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

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

av_pop

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

        SV*     av_pop(AV* ar)

av_push

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

        void    av_push(AV* ar, SV* val)

av_shift

Shifts an SV off the beginning of the array.

        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 the perlguts manpage for more information on how to use this function on tied arrays.

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

av_undef

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

        void    av_undef(AV* ar)

av_unshift

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

        void    av_unshift(AV* ar, I32 num)

get_av

Returns the AV of the specified Perl array. If create is set and the Perl variable does not exist then it will be created. If create is not set and the variable does not exist then NULL is returned.

NOTE: the perl_ form of this function is deprecated.

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

newAV

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

        AV*     newAV()

sortsv

Sort an array. Here is an example:

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

See lib/sort.pm for details about controlling the sorting algorithm.

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

Callback Functions

call_argv

Performs a callback to the specified Perl sub. See the perlcall manpage.

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 the perlcall manpage.

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 the perlcall manpage.

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 the perlcall manpage.

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 the perlcall manpage.

                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 the perlcall manpage.

                FREETMPS;

LEAVE

Closing bracket on a callback. See ENTER and the perlcall manpage.

                LEAVE;

SAVETMPS

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

                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 the perlembed manpage.

        PerlInterpreter*        perl_alloc()

perl_construct

Initializes a new Perl interpreter. See the perlembed manpage.

        void    perl_construct(PerlInterpreter* interp)

perl_destruct

Shuts down a Perl interpreter. See the perlembed manpage.

        int     perl_destruct(PerlInterpreter* interp)

perl_free

Releases a Perl interpreter. See the perlembed manpage.

        void    perl_free(PerlInterpreter* interp)

perl_parse

Tells a Perl interpreter to parse a Perl script. See the perlembed manpage.

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

perl_run

Tells a Perl interpreter to run. See the perlembed manpage.

        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, 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.

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 elipses.

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


If the PERL_PV_PRETTY_ELIPSES flag is set and not all characters in
string were output then an elipses C<...> 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 elipses.

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, char *pat, char *patend, SV **beglist, SV **endlist, SV ***next_in_list, U32 flags)

sv_2pvbyte_nolen

Return a pointer to the byte-encoded representation of the SV. May cause the SV to be downgraded from UTF-8 as a side-effect.

Usually accessed via the SvPVbyte_nolen macro.

        char*   sv_2pvbyte_nolen(SV* sv)

sv_2pvutf8_nolen

Return a pointer to the UTF-8-encoded representation of the SV. May cause the SV to be upgraded to UTF-8 as a side-effect.

Usually accessed via the SvPVutf8_nolen macro.

        char*   sv_2pvutf8_nolen(SV* sv)

sv_2pv_nolen

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

sv_catpvn_mg

Like sv_catpvn, but also handles 'set' magic.

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

sv_catsv_mg

Like sv_catsv, but also handles 'set' magic.

        void    sv_catsv_mg(SV *dstr, SV *sstr)

sv_force_normal

Undo various types of fakery on an SV: if the PV is a shared string, make a 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(char *pat, char *patend, char *s, char *strbeg, char *strend, char **new_s, I32 ocnt, U32 flags)

Functions in file pp_pack.c

packlist

The engine implementing pack() Perl function.

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

unpackstring

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

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

Global Variables

PL_modglobal

PL_modglobal is a general purpose, interpreter global HV for use by extensions that need to keep information on a per-interpreter basis. In a pinch, it can also be used as a symbol table for extensions to share data among each other. It is a good idea to use keys prefixed by the package name of the extension that owns the data.

        HV*     PL_modglobal

PL_na

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

        STRLEN  PL_na