Product Documentation

ActivePerl 5.10 Documentation

perlapi - autogenerated documentation for the perl public API

NAME
DESCRIPTION
"Gimme" Values
Array Manipulation Functions
Callback Functions
Character classes
Cloning an interpreter
CV Manipulation Functions
Embedding Functions
Functions in file dump.c
Functions in file mathoms.c
Functions in file pp_ctl.c
Functions in file pp_pack.c
GV Functions
Handy Values
Hash Manipulation Functions
Magical Functions
Memory Management
Miscellaneous Functions
MRO Functions
Multicall Functions
Numeric functions
Optree Manipulation Functions
Pad Data Structures
Per-Interpreter Variables
REGEXP Functions
Simple Exception Handling Macros
Stack Manipulation Macros
SV Flags
SV Manipulation Functions
SV-Body Allocation
Unicode Support
Variables created by xsubpp and xsubpp internal functions
Warning and Dieing
AUTHORS
SEE ALSO

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 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(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 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);

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 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, 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 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 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 the perlguts manpage 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 the perlguts manpage 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 the perlguts manpage 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 the perlguts manpage 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 the perlhack manpage). 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 the perlcall manpage.

                dMULTICALL;

MULTICALL

Make a lightweight callback. See Lightweight Callbacks in the perlcall manpage.

                MULTICALL;

POP_MULTICALL

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

                POP_MULTICALL;

PUSH_MULTICALL

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

                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.

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.

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 the perlsub manpage.

        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 the perlguts manpage.

                dXCPT;

XCPT_CATCH

Introduces a catch block. See Exception Handling in the perlguts manpage.

XCPT_RETHROW

Rethrows a previously caught exception. See Exception Handling in the perlguts manpage.

                XCPT_RETHROW;

XCPT_TRY_END

Ends a try block. See Exception Handling in the perlguts manpage.

XCPT_TRY_START

Starts a try block. See Exception Handling in the perlguts manpage.

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 the perlcall manpage.

        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 the perlcall manpage 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 the perlcall manpage.

                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

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