PERLINTERN(1pm)

NAME
perlintern - autogenerated documentation of purely internal Perl functions

DESCRIPTION
This file is the autogenerated documentation of functions in the Perl interpreter that are documented using Perl's internal documentation format but are not marked as part of the Perl API. In other words, they are not for use in extensions!

It has the same sections as perlapi, though some may be empty.

AV Handling

"AvFILLp"
    If the array "av" is empty, this returns -1; otherwise it returns the maximum value of the indices of all the array elements which are currently defined in "av". It does not handle magic, hence the "p" private indication in its name.

     SSize_t  AvFILLp(AV* av)

Callback Functions
There are only public API items currently in Callback Functions

Casting
There are only public API items currently in Casting

Character case changing
There are only public API items currently in Character case changing

Character classification
There are only public API items currently in Character classification

Compiler and Preprocessor information
There are only public API items currently in Compiler and Preprocessor information

Compiler directives
There are only public API items currently in Compiler directives

Compile-time scope hooks

"BhkENTRY"
    NOTE: "BhkENTRY" is experimental and may change or be removed without notice.

    Return an entry from the BHK structure. "which" is a preprocessor token indicating which entry to return. If the appropriate flag is not set this will return "NULL". The type of the return value depends on which entry you ask for.

     void *  BhkENTRY(BHK *hk, which)

"BhkFLAGS"
    NOTE: "BhkFLAGS" is experimental and may change or be removed without notice.

    Return the BHK's flags.

     U32  BhkFLAGS(BHK *hk)

"CALL_BLOCK_HOOKS"
    NOTE: "CALL_BLOCK_HOOKS" is experimental and may change or be removed without notice.

    Call all the registered block hooks for type "which". "which" is a preprocessing token; the type of "arg" depends on "which".

     void  CALL_BLOCK_HOOKS(which, arg)

Concurrency
There are only public API items currently in Concurrency

COP Hint Hashes
There are only public API items currently in COP Hint Hashes

Custom Operators

"core_prototype"
    This function assigns the prototype of the named core function to "sv", or to a new mortal SV if "sv" is "NULL". It returns the modified "sv", or "NULL" if the core function has no prototype. "code" is a code as returned by "keyword()". It must not be equal to 0.

     SV *  core_prototype(SV *sv, const char *name, const int code,
                          int * const opnum)

CV Handling

"CvWEAKOUTSIDE"
    Each CV has a pointer, "CvOUTSIDE()", to its lexically enclosing CV (if any). Because pointers to anonymous sub prototypes are stored in "&" pad slots, it is a possible to get a circular reference, with the parent pointing to the child and vice-versa. To avoid the ensuing memory leak, we do not increment the reference count of the CV pointed to by "CvOUTSIDE" in the one specific instance that the parent has a "&" pad slot pointing back to us. In this case, we set the "CvWEAKOUTSIDE" flag in the child. This allows us to determine under what circumstances we should decrement the refcount of the parent when freeing the child.

    There is a further complication with non-closure anonymous subs (i.e. those that do not refer to any lexicals outside that sub). In this case, the anonymous prototype is shared rather than being cloned. This has the consequence that the parent may be freed while there are still active children, e.g.,

        BEGIN { $a = sub { eval '$x' } }

    In this case, the BEGIN is freed immediately after execution since there are no active references to it: the anon sub prototype has "CvWEAKOUTSIDE" set since it's not a closure, and $a points to the same CV, so it doesn't contribute to BEGIN's refcount either. When $a is executed, the "eval '$x'" causes the chain of "CvOUTSIDE"s to be followed, and the freed BEGIN is accessed.

    To avoid this, whenever a CV and its associated pad is freed, any "&" entries in the pad are explicitly removed from the pad, and if the refcount of the pointed-to anon sub is still positive, then that child's "CvOUTSIDE" is set to point to its grandparent. This will only occur in the single specific case of a non-closure anon prototype having one or more active references (such as $a above).

    One other thing to consider is that a CV may be merely undefined rather than freed, eg "undef &foo". In this case, its refcount may not have reached zero, but we still delete its pad and its "CvROOT" etc. Since various children may still have their "CvOUTSIDE" pointing at this undefined CV, we keep its own "CvOUTSIDE" for the time being, so that the chain of lexical scopes is unbroken. For example, the following should print 123:

        my $x = 123;
        sub tmp { sub { eval '$x' } }
        my $a = tmp();
        undef &tmp;
        print  $a->();

     bool  CvWEAKOUTSIDE(CV *cv)

"docatch"
    Check for the cases 0 or 3 of cur_env.je_ret, only used inside an eval context.

    0 is used as continue inside eval,

    3 is used for a die caught by an inner eval - continue inner loop

    See cop.h: je_mustcatch, when set at any runlevel to TRUE, means eval ops must establish a local jmpenv to handle exception traps.

     OP*  docatch(Perl_ppaddr_t firstpp)

Debugging

"free_c_backtrace"
    Deallocates a backtrace received from get_c_backtrace.

     void  free_c_backtrace(Perl_c_backtrace* bt)

"get_c_backtrace"
    Collects the backtrace (aka "stacktrace") into a single linear malloced buffer, which the caller must "Perl_free_c_backtrace()".

    Scans the frames back by "depth + skip", then drops the "skip" innermost, returning at most "depth" frames.

     Perl_c_backtrace*  get_c_backtrace(int max_depth, int skip)

"PL_DBsingle"
    When Perl is run in debugging mode, with the -d switch, this SV is a boolean which indicates whether subs are being single-stepped. Single-stepping is automatically turned on after every step. This is the C variable which corresponds to Perl's $DB::single variable. See "PL_DBsub".

    On threaded perls, each thread has an independent copy of this variable; each initialized at creation time with the current value of the creating thread's copy.

     SV *  PL_DBsingle

"PL_DBsub"
    When Perl is run in debugging mode, with the -d switch, this GV contains the SV which holds the name of the sub being debugged. This is the C variable which corresponds to Perl's $DB::sub variable. See "PL_DBsingle".

    On threaded perls, each thread has an independent copy of this variable; each initialized at creation time with the current value of the creating thread's copy.

     GV *  PL_DBsub

"PL_DBtrace"
    Trace variable used when Perl is run in debugging mode, with the -d switch. This is the C variable which corresponds to Perl's $DB::trace variable. See "PL_DBsingle".

    On threaded perls, each thread has an independent copy of this variable; each initialized at creation time with the current value of the creating thread's copy.

     SV *  PL_DBtrace

Display functions
There are only public API items currently in Display functions

Embedding and Interpreter Cloning

"cv_dump"
    dump the contents of a CV

     void  cv_dump(const CV *cv, const char *title)

"cv_forget_slab"
    When a CV has a reference count on its slab ("CvSLABBED"), it is responsible for making sure it is freed. (Hence, no two CVs should ever have a reference count on the same slab.) The CV only needs to reference the slab during compilation. Once it is compiled and "CvROOT" attached, it has finished its job, so it can forget the slab.

     void  cv_forget_slab(CV *cv)

"do_dump_pad"
    Dump the contents of a padlist

     void  do_dump_pad(I32 level, PerlIO *file, PADLIST *padlist,
                       int full)

"pad_alloc_name"
    Allocates a place in the currently-compiling pad (via "pad_alloc" in perlapi) and then stores a name for that entry. "name" is adopted and becomes the name entry; it must already contain the name string. "typestash" and "ourstash" and the "padadd_STATE" flag get added to "name". None of the other processing of "pad_add_name_pvn" in perlapi is done. Returns the offset of the allocated pad slot.

     PADOFFSET  pad_alloc_name(PADNAME *name, U32 flags, HV *typestash,
                               HV *ourstash)

"pad_block_start"
    Update the pad compilation state variables on entry to a new block.

     void  pad_block_start(int full)

"pad_check_dup"
    Check for duplicate declarations: report any of:

         * a 'my' in the current scope with the same name;
         * an 'our' (anywhere in the pad) with the same name and the
           same stash as 'ourstash'

    "is_our" indicates that the name to check is an "our" declaration.

     void  pad_check_dup(PADNAME *name, U32 flags, const HV *ourstash)

"pad_findlex"
    Find a named lexical anywhere in a chain of nested pads. Add fake entries in the inner pads if it's found in an outer one.

    Returns the offset in the bottom pad of the lex or the fake lex. "cv" is the CV in which to start the search, and seq is the current "cop_seq" to match against. If "warn" is true, print appropriate warnings. The "out_"* vars return values, and so are pointers to where the returned values should be stored. "out_capture", if non-null, requests that the innermost instance of the lexical is captured; "out_name" is set to the innermost matched pad name or fake pad name; "out_flags" returns the flags normally associated with the "PARENT_FAKELEX_FLAGS" field of a fake pad name.

    Note that "pad_findlex()" is recursive; it recurses up the chain of CVs, then comes back down, adding fake entries as it goes. It has to be this way because fake names in anon prototypes have to store in "xpadn_low" the index into the parent pad.

     PADOFFSET  pad_findlex(const char *namepv, STRLEN namelen,
                            U32 flags, const CV* cv, U32 seq, int warn,
                            SV** out_capture, PADNAME** out_name,
                            int *out_flags)

"pad_fixup_inner_anons"
    For any anon CVs in the pad, change "CvOUTSIDE" of that CV from "old_cv" to "new_cv" if necessary. Needed when a newly-compiled CV has to be moved to a pre-existing CV struct.

     void  pad_fixup_inner_anons(PADLIST *padlist, CV *old_cv,
                                 CV *new_cv)

"pad_free"
    Free the SV at offset po in the current pad.

     void  pad_free(PADOFFSET po)

"pad_leavemy"
    Cleanup at end of scope during compilation: set the max seq number for lexicals in this scope and warn of any lexicals that never got introduced.

     OP *  pad_leavemy()

"padlist_dup"
    Duplicates a pad.

     PADLIST *  padlist_dup(PADLIST *srcpad, CLONE_PARAMS *param)

"padname_dup"
    Duplicates a pad name.

     PADNAME *  padname_dup(PADNAME *src, CLONE_PARAMS *param)

"padnamelist_dup"
    Duplicates a pad name list.

     PADNAMELIST *  padnamelist_dup(PADNAMELIST *srcpad,
                                    CLONE_PARAMS *param)

"pad_push"
    Push a new pad frame onto the padlist, unless there's already a pad at this depth, in which case don't bother creating a new one. Then give the new pad an @_ in slot zero.

     void  pad_push(PADLIST *padlist, int depth)

"pad_reset"
    Mark all the current temporaries for reuse

     void  pad_reset()

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

     void  pad_setsv(PADOFFSET po, SV* sv)

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

     SV*  pad_sv(PADOFFSET po)

"pad_swipe"
    Abandon the tmp in the current pad at offset "po" and replace with a new one.

     void  pad_swipe(PADOFFSET po, bool refadjust)

Errno

"dSAVEDERRNO"
    Declare variables needed to save "errno" and any operating system specific error number.

     void  dSAVEDERRNO

"dSAVE_ERRNO"
    Declare variables needed to save "errno" and any operating system specific error number, and save them for optional later restoration by "RESTORE_ERRNO".

     void  dSAVE_ERRNO

"RESTORE_ERRNO"
    Restore "errno" and any operating system specific error number that was saved by "dSAVE_ERRNO" or "RESTORE_ERRNO".

     void  RESTORE_ERRNO

"SAVE_ERRNO"
    Save "errno" and any operating system specific error number for optional later restoration by "RESTORE_ERRNO". Requires "dSAVEDERRNO" or "dSAVE_ERRNO" in scope.

     void  SAVE_ERRNO

"SETERRNO"
    Set "errno", and on VMS set "vaxc$errno".

     void  SETERRNO(int errcode, int vmserrcode)

Exception Handling (simple) Macros
There are only public API items currently in Exception Handling (simple) Macros

Filesystem configuration values
There are only public API items currently in Filesystem configuration values

Floating point configuration values
There are only public API items currently in Floating point configuration values

Formats
There are only public API items currently in Formats

General Configuration
There are only public API items currently in General Configuration

Global Variables
There are only public API items currently in Global Variables

GV Handling

"gv_stashsvpvn_cached"
    Returns a pointer to the stash for a specified package, possibly cached. Implements both ""gv_stashpvn"" in perlapi and ""gv_stashsv"" in perlapi.

    Requires one of either "namesv" or "namepv" to be non-null.

    If the flag "GV_CACHE_ONLY" is set, return the stash only if found in the cache; see ""gv_stashpvn"" in perlapi for details on the other "flags".

    Note it is strongly preferred for "namesv" to be non-null, for performance reasons.

     HV*  gv_stashsvpvn_cached(SV *namesv, const char* name,
                               U32 namelen, I32 flags)

"gv_try_downgrade"
    NOTE: "gv_try_downgrade" is experimental and may change or be removed without notice.

    If the typeglob "gv" can be expressed more succinctly, by having something other than a real GV in its place in the stash, replace it with the optimised form. Basic requirements for this are that "gv" is a real typeglob, is sufficiently ordinary, and is only referenced from its package. This function is meant to be used when a GV has been looked up in part to see what was there, causing upgrading, but based on what was found it turns out that the real GV isn't required after all.

    If "gv" is a completely empty typeglob, it is deleted from the stash.

    If "gv" is a typeglob containing only a sufficiently-ordinary constant sub, the typeglob is replaced with a scalar-reference placeholder that more compactly represents the same thing.

     void  gv_try_downgrade(GV* gv)

Hook manipulation
There are only public API items currently in Hook manipulation

HV Handling

"hv_ename_add"
    Adds a name to a stash's internal list of effective names. See "hv_ename_delete".

    This is called when a stash is assigned to a new location in the symbol table.

     void  hv_ename_add(HV *hv, const char *name, U32 len, U32 flags)

"hv_ename_delete"
    Removes a name from a stash's internal list of effective names. If this is the name returned by "HvENAME", then another name in the list will take its place ("HvENAME" will use it).

    This is called when a stash is deleted from the symbol table.

     void  hv_ename_delete(HV *hv, const char *name, U32 len,
                           U32 flags)

"refcounted_he_chain_2hv"
    Generates and returns a "HV *" representing the content of a "refcounted_he" chain. "flags" is currently unused and must be zero.

     HV *  refcounted_he_chain_2hv(const struct refcounted_he *c,
                                   U32 flags)

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

     SV *  refcounted_he_fetch_pv(const struct refcounted_he *chain,
                                  const char *key, U32 hash, U32 flags)

"refcounted_he_fetch_pvn"
    Search along a "refcounted_he" chain for an entry with the key specified by "keypv" and "keylen". If "flags" has the "REFCOUNTED_HE_KEY_UTF8" bit set, the key octets are interpreted as UTF-8, otherwise they are interpreted as Latin-1. "hash" is a precomputed hash of the key string, or zero if it has not been precomputed. Returns a mortal scalar representing the value associated with the key, or &PL_sv_placeholder if there is no value associated with the key.

     SV *  refcounted_he_fetch_pvn(const struct refcounted_he *chain,
                                   const char *keypv, STRLEN keylen,
                                   U32 hash, U32 flags)

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

     SV *  refcounted_he_fetch_pvs(const struct refcounted_he *chain,
                                   "key", U32 flags)

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

     SV *  refcounted_he_fetch_sv(const struct refcounted_he *chain,
                                  SV *key, U32 hash, U32 flags)

"refcounted_he_free"
    Decrements the reference count of a "refcounted_he" by one. If the reference count reaches zero the structure's memory is freed, which (recursively) causes a reduction of its parent "refcounted_he"'s reference count. It is safe to pass a null pointer to this function: no action occurs in this case.

     void  refcounted_he_free(struct refcounted_he *he)

"refcounted_he_inc"
    Increment the reference count of a "refcounted_he". The pointer to the "refcounted_he" is also returned. It is safe to pass a null pointer to this function: no action occurs and a null pointer is returned.

     struct refcounted_he *  refcounted_he_inc(
                                              struct refcounted_he *he)

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

     struct refcounted_he *  refcounted_he_new_pv(
                                          struct refcounted_he *parent,
                                          const char *key, U32 hash,
                                          SV *value, U32 flags)

"refcounted_he_new_pvn"
    Creates a new "refcounted_he". This consists of a single key/value pair and a reference to an existing "refcounted_he" chain (which may be empty), and thus forms a longer chain. When using the longer chain, the new key/value pair takes precedence over any entry for the same key further along the chain.

    The new key is specified by "keypv" and "keylen". If "flags" has the "REFCOUNTED_HE_KEY_UTF8" bit set, the key octets are interpreted as UTF-8, otherwise they are interpreted as Latin-1. "hash" is a precomputed hash of the key string, or zero if it has not been precomputed.

    "value" is the scalar value to store for this key. "value" is copied by this function, which thus does not take ownership of any reference to it, and later changes to the scalar will not be reflected in the value visible in the "refcounted_he". Complex types of scalar will not be stored with referential integrity, but will be coerced to strings. "value" may be either null or &PL_sv_placeholder to indicate that no value is to be associated with the key; this, as with any non-null value, takes precedence over the existence of a value for the key further along the chain.

    "parent" points to the rest of the "refcounted_he" chain to be attached to the new "refcounted_he". This function takes ownership of one reference to "parent", and returns one reference to the new "refcounted_he".

     struct refcounted_he *  refcounted_he_new_pvn(
                                          struct refcounted_he *parent,
                                          const char *keypv,
                                          STRLEN keylen, U32 hash,
                                          SV *value, U32 flags)

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

     struct refcounted_he *  refcounted_he_new_pvs(
                                          struct refcounted_he *parent,
                                          "key", SV *value, U32 flags)

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

     struct refcounted_he *  refcounted_he_new_sv(
                                          struct refcounted_he *parent,
                                          SV *key, U32 hash, SV *value,
                                          U32 flags)

Input/Output

"PL_last_in_gv"
    The GV which was last used for a filehandle input operation. ("<FH>")

    On threaded perls, each thread has an independent copy of this variable; each initialized at creation time with the current value of the creating thread's copy.

     GV*  PL_last_in_gv

"PL_ofsgv"
    The glob containing the output field separator - "*," in Perl space.

    On threaded perls, each thread has an independent copy of this variable; each initialized at creation time with the current value of the creating thread's copy.

     GV*  PL_ofsgv

"PL_rs"
    The input record separator - $/ in Perl space.

    On threaded perls, each thread has an independent copy of this variable; each initialized at creation time with the current value of the creating thread's copy.

     SV*  PL_rs

"start_glob"
    NOTE: "start_glob" is experimental and may change or be removed without notice.

    Function called by "do_readline" to spawn a glob (or do the glob inside perl on VMS). This code used to be inline, but now perl uses "File::Glob" this glob starter is only used by miniperl during the build process, or when PERL_EXTERNAL_GLOB is defined. Moving it away shrinks pp_hot.c; shrinking pp_hot.c helps speed perl up.

    NOTE: "start_glob" must be explicitly called as "Perl_start_glob" with an "aTHX_" parameter.

     PerlIO*  Perl_start_glob(pTHX_ SV *tmpglob, IO *io)

Integer configuration values
There are only public API items currently in Integer configuration values

Lexer interface

"validate_proto"
    NOTE: "validate_proto" is experimental and may change or be removed without notice.

    This function performs syntax checking on a prototype, "proto". If "warn" is true, any illegal characters or mismatched brackets will trigger illegalproto warnings, declaring that they were detected in the prototype for "name".

    The return value is "true" if this is a valid prototype, and "false" if it is not, regardless of whether "warn" was "true" or "false".

    Note that "NULL" is a valid "proto" and will always return "true".

     bool  validate_proto(SV *name, SV *proto, bool warn,
                          bool curstash)

Locales
There are only public API items currently in Locales

Magic

"magic_clearhint"
    Triggered by a delete from "%^H", records the key to "PL_compiling.cop_hints_hash".

     int  magic_clearhint(SV* sv, MAGIC* mg)

"magic_clearhints"
    Triggered by clearing "%^H", resets "PL_compiling.cop_hints_hash".

     int  magic_clearhints(SV* sv, MAGIC* mg)

"magic_methcall"
    Invoke a magic method (like FETCH).

    "sv" and "mg" are the tied thingy and the tie magic.

    "meth" is the name of the method to call.

    "argc" is the number of args (in addition to $self) to pass to the method.

    The "flags" can be:

        G_DISCARD     invoke method with G_DISCARD flag and don't
                      return a value
        G_UNDEF_FILL  fill the stack with argc pointers to
                      PL_sv_undef

    The arguments themselves are any values following the "flags" argument.

    Returns the SV (if any) returned by the method, or "NULL" on failure.

    NOTE: "magic_methcall" must be explicitly called as "Perl_magic_methcall" with an "aTHX_" parameter.

     SV*  Perl_magic_methcall(pTHX_ SV *sv, const MAGIC *mg, SV *meth,
                              U32 flags, U32 argc, ...)

"magic_sethint"
    Triggered by a store to "%^H", records the key/value pair to "PL_compiling.cop_hints_hash". It is assumed that hints aren't storing anything that would need a deep copy. Maybe we should warn if we find a reference.

     int  magic_sethint(SV* sv, MAGIC* mg)

"mg_localize"
    Copy some of the magic from an existing SV to new localized version of that SV. Container magic (e.g., %ENV, $1, "tie") gets copied, value magic doesn't (e.g., "taint", "pos").

    If "setmagic" is false then no set magic will be called on the new (empty) SV. This typically means that assignment will soon follow (e.g. 'local $x = $y'), and that will handle the magic.

     void  mg_localize(SV* sv, SV* nsv, bool setmagic)

Memory Management
There are only public API items currently in Memory Management

MRO

"mro_get_linear_isa_dfs"
    Returns the Depth-First Search linearization of @ISA the given stash. The return value is a read-only AV*. "level" should be 0 (it is used internally in this function's recursion).

    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_dfs(HV* stash, U32 level)

"mro_isa_changed_in"
    Takes the necessary steps (cache invalidations, mostly) when the @ISA of the given package has changed. Invoked by the "setisa" magic, should not need to invoke directly.

     void  mro_isa_changed_in(HV* stash)

"mro_package_moved"
    Call this function to signal to a stash that it has been assigned to another spot in the stash hierarchy. "stash" is the stash that has been assigned. "oldstash" is the stash it replaces, if any. "gv" is the glob that is actually being assigned to.

    This can also be called with a null first argument to indicate that "oldstash" has been deleted.

    This function invalidates isa caches on the old stash, on all subpackages nested inside it, and on the subclasses of all those, including non-existent packages that have corresponding entries in "stash".

    It also sets the effective names ("HvENAME") on all the stashes as appropriate.

    If the "gv" is present and is not in the symbol table, then this function simply returns. This checked will be skipped if "flags & 1".

     void  mro_package_moved(HV * const stash, HV * const oldstash,
                             const GV * const gv, U32 flags)

Multicall Functions
There are only public API items currently in Multicall Functions

Numeric Functions

"grok_atoUV"
    parse a string, looking for a decimal unsigned integer.

    On entry, "pv" points to the beginning of the string; "valptr" points to a UV that will receive the converted value, if found; "endptr" is either NULL or points to a variable that points to one byte beyond the point in "pv" that this routine should examine. If "endptr" is NULL, "pv" is assumed to be NUL-terminated.

    Returns FALSE if "pv" doesn't represent a valid unsigned integer value (with no leading zeros). Otherwise it returns TRUE, and sets *valptr to that value.

    If you constrain the portion of "pv" that is looked at by this function (by passing a non-NULL "endptr"), and if the intial bytes of that portion form a valid value, it will return TRUE, setting *endptr to the byte following the final digit of the value. But if there is no constraint at what's looked at, all of "pv" must be valid in order for TRUE to be returned. *endptr is unchanged from its value on input if FALSE is returned;

    The only characters this accepts are the decimal digits '0'..'9'.

    As opposed to atoi(3) or strtol(3), "grok_atoUV" does NOT allow optional leading whitespace, nor negative inputs. If such features are required, the calling code needs to explicitly implement those.

    Note that this function returns FALSE for inputs that would overflow a UV, or have leading zeros. Thus a single 0 is accepted, but not 00 nor 01, 002, etc.

    Background: "atoi" has severe problems with illegal inputs, it cannot be used for incremental parsing, and therefore should be avoided "atoi" and "strtol" are also affected by locale settings, which can also be seen as a bug (global state controlled by user environment).

     bool  grok_atoUV(const char* pv, UV* valptr, const char** endptr)

"isinfnansv"
    Checks whether the argument would be either an infinity or "NaN" when used as a number, but is careful not to trigger non-numeric or uninitialized warnings. it assumes the caller has done "SvGETMAGIC(sv)" already.

     bool  isinfnansv(SV *sv)

Optree construction
There are only public API items currently in Optree construction

Optree Manipulation Functions

"finalize_optree"
    This function finalizes the optree. Should be called directly after the complete optree is built. It does some additional checking which can't be done in the normal "ck_"xxx functions and makes the tree thread-safe.

     void  finalize_optree(OP* o)

"newATTRSUB_x"
    Construct a Perl subroutine, also performing some surrounding jobs.

    This function is expected to be called in a Perl compilation context, and some aspects of the subroutine are taken from global variables associated with compilation. In particular, "PL_compcv" represents the subroutine that is currently being compiled. It must be non-null when this function is called, and some aspects of the subroutine being constructed are taken from it. The constructed subroutine may actually be a reuse of the "PL_compcv" object, but will not necessarily be so.

    If "block" is null then the subroutine will have no body, and for the time being it will be an error to call it. This represents a forward subroutine declaration such as "sub foo ($$);". If "block" is non-null then it provides the Perl code of the subroutine body, which will be executed when the subroutine is called. This body includes any argument unwrapping code resulting from a subroutine signature or similar. The pad use of the code must correspond to the pad attached to "PL_compcv". The code is not expected to include a "leavesub" or "leavesublv" op; this function will add such an op. "block" is consumed by this function and will become part of the constructed subroutine.

    "proto" specifies the subroutine's prototype, unless one is supplied as an attribute (see below). If "proto" is null, then the subroutine will not have a prototype. If "proto" is non-null, it must point to a "const" op whose value is a string, and the subroutine will have that string as its prototype. If a prototype is supplied as an attribute, the attribute takes precedence over "proto", but in that case "proto" should preferably be null. In any case, "proto" is consumed by this function.

    "attrs" supplies attributes to be applied the subroutine. A handful of attributes take effect by built-in means, being applied to "PL_compcv" immediately when seen. Other attributes are collected up and attached to the subroutine by this route. "attrs" may be null to supply no attributes, or point to a "const" op for a single attribute, or point to a "list" op whose children apart from the "pushmark" are "const" ops for one or more attributes. Each "const" op must be a string, giving the attribute name optionally followed by parenthesised arguments, in the manner in which attributes appear in Perl source. The attributes will be applied to the sub by this function. "attrs" is consumed by this function.

    If "o_is_gv" is false and "o" is null, then the subroutine will be anonymous. If "o_is_gv" is false and "o" is non-null, then "o" must point to a "const" OP, which will be consumed by this function, and its string value supplies a name for the subroutine. The name may be qualified or unqualified, and if it is unqualified then a default stash will be selected in some manner. If "o_is_gv" is true, then "o" doesn't point to an "OP" at all, but is instead a cast pointer to a "GV" by which the subroutine will be named.

    If there is already a subroutine of the specified name, then the new sub will either replace the existing one in the glob or be merged with the existing one. A warning may be generated about redefinition.

    If the subroutine has one of a few special names, such as "BEGIN" or "END", then it will be claimed by the appropriate queue for automatic running of phase-related subroutines. In this case the relevant glob will be left not containing any subroutine, even if it did contain one before. In the case of "BEGIN", the subroutine will be executed and the reference to it disposed of before this function returns.

    The function returns a pointer to the constructed subroutine. If the sub is anonymous then ownership of one counted reference to the subroutine is transferred to the caller. If the sub is named then the caller does not get ownership of a reference. In most such cases, where the sub has a non-phase name, the sub will be alive at the point it is returned by virtue of being contained in the glob that names it. A phase-named subroutine will usually be alive by virtue of the reference owned by the phase's automatic run queue. But a "BEGIN" subroutine, having already been executed, will quite likely have been destroyed already by the time this function returns, making it erroneous for the caller to make any use of the returned pointer. It is the caller's responsibility to ensure that it knows which of these situations applies.

     CV*  newATTRSUB_x(I32 floor, OP *o, OP *proto, OP *attrs,
                       OP *block, bool o_is_gv)

"newXS_len_flags"
    Construct an XS subroutine, also performing some surrounding jobs.

    The subroutine will have the entry point "subaddr". It will have the prototype specified by the nul-terminated string "proto", or no prototype if "proto" is null. The prototype string is copied; the caller can mutate the supplied string afterwards. If "filename" is non-null, it must be a nul-terminated filename, and the subroutine will have its "CvFILE" set accordingly. By default "CvFILE" is set to point directly to the supplied string, which must be static. If "flags" has the "XS_DYNAMIC_FILENAME" bit set, then a copy of the string will be taken instead.

    Other aspects of the subroutine will be left in their default state. If anything else needs to be done to the subroutine for it to function correctly, it is the caller's responsibility to do that after this function has constructed it. However, beware of the subroutine potentially being destroyed before this function returns, as described below.

    If "name" is null then the subroutine will be anonymous, with its "CvGV" referring to an "__ANON__" glob. If "name" is non-null then the subroutine will be named accordingly, referenced by the appropriate glob. "name" is a string of length "len" bytes giving a sigilless symbol name, in UTF-8 if "flags" has the "SVf_UTF8" bit set and in Latin-1 otherwise. The name may be either qualified or unqualified, with the stash defaulting in the same manner as for "gv_fetchpvn_flags". "flags" may contain flag bits understood by "gv_fetchpvn_flags" with the same meaning as they have there, such as "GV_ADDWARN". The symbol is always added to the stash if necessary, with "GV_ADDMULTI" semantics.

    If there is already a subroutine of the specified name, then the new sub will replace the existing one in the glob. A warning may be generated about the redefinition. If the old subroutine was "CvCONST" then the decision about whether to warn is influenced by an expectation about whether the new subroutine will become a constant of similar value. That expectation is determined by "const_svp". (Note that the call to this function doesn't make the new subroutine "CvCONST" in any case; that is left to the caller.) If "const_svp" is null then it indicates that the new subroutine will not become a constant. If "const_svp" is non-null then it indicates that the new subroutine will become a constant, and it points to an "SV*" that provides the constant value that the subroutine will have.

    If the subroutine has one of a few special names, such as "BEGIN" or "END", then it will be claimed by the appropriate queue for automatic running of phase-related subroutines. In this case the relevant glob will be left not containing any subroutine, even if it did contain one before. In the case of "BEGIN", the subroutine will be executed and the reference to it disposed of before this function returns, and also before its prototype is set. If a "BEGIN" subroutine would not be sufficiently constructed by this function to be ready for execution then the caller must prevent this happening by giving the subroutine a different name.

    The function returns a pointer to the constructed subroutine. If the sub is anonymous then ownership of one counted reference to the subroutine is transferred to the caller. If the sub is named then the caller does not get ownership of a reference. In most such cases, where the sub has a non-phase name, the sub will be alive at the point it is returned by virtue of being contained in the glob that names it. A phase-named subroutine will usually be alive by virtue of the reference owned by the phase's automatic run queue. But a "BEGIN" subroutine, having already been executed, will quite likely have been destroyed already by the time this function returns, making it erroneous for the caller to make any use of the returned pointer. It is the caller's responsibility to ensure that it knows which of these situations applies.

     CV *  newXS_len_flags(const char *name, STRLEN len,
                           XSUBADDR_t subaddr,
                           const char *const filename,
                           const char *const proto, SV **const_svp,
                           U32 flags)

"optimize_optree"
    This function applies some optimisations to the optree in top-down order. It is called before the peephole optimizer, which processes ops in execution order. Note that finalize_optree() also does a top-down scan, but is called *after* the peephole optimizer.

     void  optimize_optree(OP* o)

"traverse_op_tree"
    Return the next op in a depth-first traversal of the op tree, returning NULL when the traversal is complete.

    The initial call must supply the root of the tree as both top and o.

    For now it's static, but it may be exposed to the API in the future.

     OP*  traverse_op_tree(OP* top, OP* o)

Pack and Unpack
There are only public API items currently in Pack and Unpack

Pad Data Structures

"CX_CURPAD_SAVE"
    Save the current pad in the given context block structure.

     void  CX_CURPAD_SAVE(struct context)

"CX_CURPAD_SV"
    Access the SV at offset "po" in the saved current pad in the given context block structure (can be used as an lvalue).

     SV *  CX_CURPAD_SV(struct context, PADOFFSET po)

"PAD_BASE_SV"
    Get the value from slot "po" in the base (DEPTH=1) pad of a padlist

     SV *  PAD_BASE_SV(PADLIST padlist, PADOFFSET po)

"PAD_CLONE_VARS"
    Clone the state variables associated with running and compiling pads.

     void  PAD_CLONE_VARS(PerlInterpreter *proto_perl,
                          CLONE_PARAMS* param)

"PAD_COMPNAME_FLAGS"
    Return the flags for the current compiling pad name at offset "po". Assumes a valid slot entry.

     U32  PAD_COMPNAME_FLAGS(PADOFFSET po)

"PAD_COMPNAME_GEN"
    The generation number of the name at offset "po" in the current compiling pad (lvalue).

     STRLEN  PAD_COMPNAME_GEN(PADOFFSET po)

"PAD_COMPNAME_GEN_set"
    Sets the generation number of the name at offset "po" in the current ling pad (lvalue) to "gen".

     STRLEN  PAD_COMPNAME_GEN_set(PADOFFSET po, int gen)

"PAD_COMPNAME_OURSTASH"
    Return the stash associated with an "our" variable. Assumes the slot entry is a valid "our" lexical.

     HV *  PAD_COMPNAME_OURSTASH(PADOFFSET po)

"PAD_COMPNAME_PV"
    Return the name of the current compiling pad name at offset "po". Assumes a valid slot entry.

     char *  PAD_COMPNAME_PV(PADOFFSET po)

"PAD_COMPNAME_TYPE"
    Return the type (stash) of the current compiling pad name at offset "po". Must be a valid name. Returns null if not typed.

     HV *  PAD_COMPNAME_TYPE(PADOFFSET po)

"PadnameIsOUR"
    Whether this is an "our" variable.

     bool  PadnameIsOUR(PADNAME * pn)

"PadnameIsSTATE"
    Whether this is a "state" variable.

     bool  PadnameIsSTATE(PADNAME * pn)

"PadnameOURSTASH"
    The stash in which this "our" variable was declared.

     HV *  PadnameOURSTASH(PADNAME * pn)

"PadnameOUTER"
    Whether this entry belongs to an outer pad. Entries for which this is true are often referred to as 'fake'.

     bool  PadnameOUTER(PADNAME * pn)

"PadnameTYPE"
    The stash associated with a typed lexical. This returns the %Foo:: hash for "my Foo $bar".

     HV *  PadnameTYPE(PADNAME * pn)

"PAD_RESTORE_LOCAL"
    Restore the old pad saved into the local variable "opad" by "PAD_SAVE_LOCAL()"

     void  PAD_RESTORE_LOCAL(PAD *opad)

"PAD_SAVE_LOCAL"
    Save the current pad to the local variable "opad", then make the current pad equal to "npad"

     void  PAD_SAVE_LOCAL(PAD *opad, PAD *npad)

"PAD_SAVE_SETNULLPAD"
    Save the current pad then set it to null.

     void  PAD_SAVE_SETNULLPAD()

"PAD_SETSV"
    Set the slot at offset "po" in the current pad to "sv"

     SV *  PAD_SETSV(PADOFFSET po, SV* sv)

"PAD_SET_CUR"
    Set the current pad to be pad "n" in the padlist, saving the previous current pad. NB currently this macro expands to a string too long for some compilers, so it's best to replace it with

        SAVECOMPPAD();
        PAD_SET_CUR_NOSAVE(padlist,n);

     void  PAD_SET_CUR(PADLIST padlist, I32 n)

"PAD_SET_CUR_NOSAVE"
    like PAD_SET_CUR, but without the save

     void  PAD_SET_CUR_NOSAVE(PADLIST padlist, I32 n)

"PAD_SV"
    Get the value at offset "po" in the current pad

     SV *  PAD_SV(PADOFFSET po)

"PAD_SVl"
    Lightweight and lvalue version of "PAD_SV". Get or set the value at offset "po" in the current pad. Unlike "PAD_SV", does not print diagnostics with -DX. For internal use only.

     SV *  PAD_SVl(PADOFFSET po)

"SAVECLEARSV"
    Clear the pointed to pad value on scope exit. (i.e. the runtime action of "my")

     void  SAVECLEARSV(SV **svp)

"SAVECOMPPAD"
    save "PL_comppad" and "PL_curpad"

     void  SAVECOMPPAD()

"SAVEPADSV"
    Save a pad slot (used to restore after an iteration)

     void  SAVEPADSV(PADOFFSET po)

Password and Group access
There are only public API items currently in Password and Group access

Paths to system commands
There are only public API items currently in Paths to system commands

Prototype information
There are only public API items currently in Prototype information

REGEXP Functions
There are only public API items currently in REGEXP Functions

Signals
There are only public API items currently in Signals

Site configuration
There are only public API items currently in Site configuration

Sockets configuration values
There are only public API items currently in Sockets configuration values

Source Filters
There are only public API items currently in Source Filters

Stack Manipulation Macros

"djSP"
    Declare Just "SP". This is actually identical to "dSP", and declares a local copy of perl's stack pointer, available via the "SP" macro. See ""SP" in perlapi". (Available for backward source code compatibility with the old (Perl 5.005) thread model.)

       djSP();

"LVRET"
    True if this op will be the return value of an lvalue subroutine

String Handling

"delimcpy_no_escape"
    Copy a source buffer to a destination buffer, stopping at (but not including) the first occurrence in the source of the delimiter byte, "delim". The source is the bytes between "from" and "from_end" - 1. Similarly, the dest is "to" up to "to_end".

    The number of bytes copied is written to *retlen.

    Returns the position of "delim" in the "from" buffer, but if there is no such occurrence before "from_end", then "from_end" is returned, and the entire buffer "from" .. "from_end" - 1 is copied.

    If there is room in the destination available after the copy, an extra terminating safety "NUL" byte is appended (not included in the returned length).

    The error case is if the destination buffer is not large enough to accommodate everything that should be copied. In this situation, a value larger than "to_end" - "to" is written to *retlen, and as much of the source as fits will be written to the destination. Not having room for the safety "NUL" is not considered an error.

     char*  delimcpy_no_escape(char* to, const char* to_end,
                               const char* from, const char* from_end,
                               const int delim, I32* retlen)

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

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

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

     bool  quadmath_format_needed(const char* format)

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

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

    Returns true if it is valid, false if not.

    See also "quadmath_format_needed".

     bool  quadmath_format_valid(const char* format)

SV Flags

"SVt_INVLIST"
    Type flag for scalars. See "svtype" in perlapi.

SV Handling

"PL_Sv"
    A scratch pad SV for whatever temporary use you need. Chiefly used as a fallback by macros on platforms where "PERL_USE_GCC_BRACE_GROUPS" in perlapi> is unavailable, and which would otherwise evaluate their SV parameter more than once.

       PL_Sv

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

     bool  sv_2bool(SV *const sv)

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

     bool  sv_2bool_flags(SV *sv, I32 flags)

"sv_2num"
    NOTE: "sv_2num" is experimental and may change or be removed without notice.

    Return an SV with the numeric value of the source SV, doing any necessary reference or overload conversion. The caller is expected to have handled get-magic already.

     SV*  sv_2num(SV *const sv)

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

     char*  sv_2pv_flags(SV *const sv, STRLEN *const lp,
                         const U32 flags)

"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_add_arena"
    Given a chunk of memory, link it to the head of the list of arenas, and split it into a list of free SVs.

     void  sv_add_arena(char *const ptr, const U32 size,
                        const U32 flags)

"sv_clean_all"
    Decrement the refcnt of each remaining SV, possibly triggering a cleanup. This function may have to be called multiple times to free SVs which are in complex self-referential hierarchies.

     I32  sv_clean_all()

"sv_clean_objs"
    Attempt to destroy all objects not yet freed.

     void  sv_clean_objs()

"sv_free_arenas"
    Deallocate the memory used by all arenas. Note that all the individual SV heads and bodies within the arenas must already have been freed.

     void  sv_free_arenas()

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

     char*  sv_grow(SV *const sv, STRLEN newlen)

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

    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_newref"
    Increment an SV's reference count. Use the "SvREFCNT_inc()" wrapper instead.

     SV*  sv_newref(SV *const sv)

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

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

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

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

"sv_pvbyten_force"
    The backend for the "SvPVbytex_force" macro. Always use the macro instead. If the SV cannot be downgraded from UTF-8, this croaks.

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

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

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

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

"sv_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_pvutf8"
    Use the "SvPVutf8_nolen" macro instead

     char*  sv_pvutf8(SV *sv)

"sv_pvutf8n"
    "DEPRECATED!" It is planned to remove "sv_pvutf8n" from a future release of Perl. Do not use it for new code; remove it from existing code.

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

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

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

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

"sv_taint"
    Taint an SV. Use "SvTAINTED_on" instead.

     void  sv_taint(SV* sv)

"sv_tainted"
    Test an SV for taintedness. Use "SvTAINTED" instead.

     bool  sv_tainted(SV *const sv)

"SvTHINKFIRST"
    A quick flag check to see whether an "sv" should be passed to "sv_force_normal" to be "downgraded" before "SvIVX" or "SvPVX" can be modified directly.

    For example, if your scalar is a reference and you want to modify the "SvIVX" slot, you can't just do "SvROK_off", as that will leak the referent.

    This is used internally by various sv-modifying functions, such as "sv_setsv", "sv_setiv" and "sv_pvn_force".

    One case that this does not handle is a gv without SvFAKE set. After

        if (SvTHINKFIRST(gv)) sv_force_normal(gv);

    it will still be a gv.

    "SvTHINKFIRST" sometimes produces false positives. In those cases "sv_force_normal" does nothing.

     U32  SvTHINKFIRST(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 *const sv)

"sv_untaint"
    Untaint an SV. Use "SvTAINTED_off" instead.

     void  sv_untaint(SV *const sv)

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

    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)

Time
There are only public API items currently in Time

Typedef names
There are only public API items currently in Typedef names

Unicode Support

"bytes_from_utf8_loc"
    NOTE: "bytes_from_utf8_loc" is experimental and may change or be removed without notice.

    Like ""bytes_from_utf8" in perlapi()", but takes an extra parameter, a pointer to where to store the location of the first character in "s" that cannot be converted to non-UTF8.

    If that parameter is "NULL", this function behaves identically to "bytes_from_utf8".

    Otherwise if *is_utf8p is 0 on input, the function behaves identically to "bytes_from_utf8", except it also sets *first_non_downgradable to "NULL".

    Otherwise, the function returns a newly created "NUL"-terminated string containing the non-UTF8 equivalent of the convertible first portion of "s". *lenp is set to its length, not including the terminating "NUL". If the entire input string was converted, *is_utf8p is set to a FALSE value, and *first_non_downgradable is set to "NULL".

    Otherwise, *first_non_downgradable is set to point to the first byte of the first character in the original string that wasn't converted. *is_utf8p is unchanged. Note that the new string may have length 0.

    Another way to look at it is, if *first_non_downgradable is non-"NULL" and *is_utf8p is TRUE, this function starts at the beginning of "s" and converts as many characters in it as possible stopping at the first one it finds that can't be converted to non-UTF-8. *first_non_downgradable is set to point to that. The function returns the portion that could be converted in a newly created "NUL"-terminated string, and *lenp is set to its length, not including the terminating "NUL". If the very first character in the original could not be converted, *lenp will be 0, and the new string will contain just a single "NUL". If the entire input string was converted, *is_utf8p is set to FALSE and *first_non_downgradable is set to "NULL".

    Upon successful return, the number of variants in the converted portion of the string can be computed by having saved the value of *lenp before the call, and subtracting the after-call value of *lenp from it.

     U8*  bytes_from_utf8_loc(const U8 *s, STRLEN *lenp,
                              bool *is_utf8p,
                              const U8 ** first_unconverted)

"find_uninit_var"
    NOTE: "find_uninit_var" is experimental and may change or be removed without notice.

    Find the name of the undefined variable (if any) that caused the operator to issue a "Use of uninitialized value" warning. If match is true, only return a name if its value matches "uninit_sv". So roughly speaking, if a unary operator (such as "OP_COS") generates a warning, then following the direct child of the op may yield an "OP_PADSV" or "OP_GV" that gives the name of the undefined variable. On the other hand, with "OP_ADD" there are two branches to follow, so we only print the variable name if we get an exact match. "desc_p" points to a string pointer holding the description of the op. This may be updated if needed.

    The name is returned as a mortal SV.

    Assumes that "PL_op" is the OP that originally triggered the error, and that "PL_comppad"/"PL_curpad" points to the currently executing pad.

     SV*  find_uninit_var(const OP *const obase,
                          const SV *const uninit_sv, bool match,
                          const char **desc_p)

"isSCRIPT_RUN"
    Returns a bool as to whether or not the sequence of bytes from "s" up to but not including "send" form a "script run". "utf8_target" is TRUE iff the sequence starting at "s" is to be treated as UTF-8. To be precise, except for two degenerate cases given below, this function returns TRUE iff all code points in it come from any combination of three "scripts" given by the Unicode "Script Extensions" property: Common, Inherited, and possibly one other. Additionally all decimal digits must come from the same consecutive sequence of 10.

    For example, if all the characters in the sequence are Greek, or Common, or Inherited, this function will return TRUE, provided any decimal digits in it are from the same block of digits in Common. (These are the ASCII digits "0".."9" and additionally a block for full width forms of these, and several others used in mathematical notation.) For scripts (unlike Greek) that have their own digits defined this will accept either digits from that set or from one of the Common digit sets, but not a combination of the two. Some scripts, such as Arabic, have more than one set of digits. All digits must come from the same set for this function to return TRUE.

    *ret_script, if "ret_script" is not NULL, will on return of TRUE contain the script found, using the "SCX_enum" typedef. Its value will be "SCX_INVALID" if the function returns FALSE.

    If the sequence is empty, TRUE is returned, but *ret_script (if asked for) will be "SCX_INVALID".

    If the sequence contains a single code point which is unassigned to a character in the version of Unicode being used, the function will return TRUE, and the script will be "SCX_Unknown". Any other combination of unassigned code points in the input sequence will result in the function treating the input as not being a script run.

    The returned script will be "SCX_Inherited" iff all the code points in it are from the Inherited script.

    Otherwise, the returned script will be "SCX_Common" iff all the code points in it are from the Inherited or Common scripts.

     bool  isSCRIPT_RUN(const U8 *s, const U8 *send,
                        const bool utf8_target)

"is_utf8_non_invariant_string"
    Returns TRUE if "is_utf8_invariant_string" in perlapi returns FALSE for the first "len" bytes of the string "s", but they are, nonetheless, legal Perl-extended UTF-8; otherwise returns FALSE.

    A TRUE return means that at least one code point represented by the sequence either is a wide character not representable as a single byte, or the representation differs depending on whether the sequence is encoded in UTF-8 or not.

    See also ""is_utf8_invariant_string" in perlapi", ""is_utf8_string" in perlapi"

     bool  is_utf8_non_invariant_string(const U8* const s, STRLEN len)

"report_uninit"
    Print appropriate "Use of uninitialized variable" warning.

     void  report_uninit(const SV *uninit_sv)

"utf8n_to_uvuni"
    "DEPRECATED!" It is planned to remove "utf8n_to_uvuni" from a future release of Perl. Do not use it for new code; remove it from existing code.

    Instead use "utf8_to_uvchr_buf" in perlapi, or rarely, "utf8n_to_uvchr" in perlapi.

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

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

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

    Returns the Unicode code point of the first character in the string "s" which is assumed to be in UTF-8 encoding; "retlen" will be set to the length, in bytes, of that character.

    Some, but not all, UTF-8 malformations are detected, and in fact, some malformed input could cause reading beyond the end of the input buffer, which is one reason why this function is deprecated. The other is that only in extremely limited circumstances should the Unicode versus native code point be of any interest to you. See "utf8_to_uvuni_buf" for alternatives.

    If "s" points to one of the detected malformations, and UTF8 warnings are enabled, zero is returned and *retlen is set (if "retlen" doesn't point to NULL) to -1. If those warnings are off, the computed value if well-defined (or the Unicode REPLACEMENT CHARACTER, if not) is silently returned, and *retlen is set (if "retlen" isn't NULL) so that ("s" + *retlen) is the next possible position in "s" that could begin a non-malformed character. See "utf8n_to_uvchr" in perlapi for details on when the REPLACEMENT CHARACTER is returned.

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

"utf8_to_uvuni_buf"
    "DEPRECATED!" It is planned to remove "utf8_to_uvuni_buf" from a future release of Perl. Do not use it for new code; remove it from existing code.

    Only in very rare circumstances should code need to be dealing in Unicode (as opposed to native) code points. In those few cases, use "NATIVE_TO_UNI(utf8_to_uvchr_buf(...))" instead. If you are not absolutely sure this is one of those cases, then assume it isn't and use plain "utf8_to_uvchr_buf" instead.

    Returns the Unicode (not-native) code point of the first character in the string "s" which is assumed to be in UTF-8 encoding; "send" points to 1 beyond the end of "s". "retlen" will be set to the length, in bytes, of that character.

    If "s" does not point to a well-formed UTF-8 character and UTF8 warnings are enabled, zero is returned and *retlen is set (if "retlen" isn't NULL) to -1. If those warnings are off, the computed value if well-defined (or the Unicode REPLACEMENT CHARACTER, if not) is silently returned, and *retlen is set (if "retlen" isn't NULL) so that ("s" + *retlen) is the next possible position in "s" that could begin a non-malformed character. See "utf8n_to_uvchr" in perlapi for details on when the REPLACEMENT CHARACTER is returned.

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

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

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

    For details, see the description for "uvchr_to_utf8_flags" in perlapi.

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

"uvuni_to_utf8_flags"
    "DEPRECATED!" It is planned to remove "uvuni_to_utf8_flags" from a future release of Perl. Do not use it for new code; remove it from existing code.

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

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

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

"valid_utf8_to_uvchr"
    Like ""utf8_to_uvchr_buf" in perlapi", but should only be called when it is known that the next character in the input UTF-8 string "s" is well-formed (e.g., it passes ""isUTF8_CHAR" in perlapi". Surrogates, non-character code points, and non-Unicode code points are allowed.

     UV  valid_utf8_to_uvchr(const U8 *s, STRLEN *retlen)

"variant_under_utf8_count"
    This function looks at the sequence of bytes between "s" and "e", which are assumed to be encoded in ASCII/Latin1, and returns how many of them would change should the string be translated into UTF-8. Due to the nature of UTF-8, each of these would occupy two bytes instead of the single one in the input string. Thus, this function returns the precise number of bytes the string would expand by when translated to UTF-8.

    Unlike most of the other functions that have "utf8" in their name, the input to this function is NOT a UTF-8-encoded string. The function name is slightly odd to emphasize this.

    This function is internal to Perl because khw thinks that any XS code that would want this is probably operating too close to the internals. Presenting a valid use case could change that.

    See also ""is_utf8_invariant_string" in perlapi" and ""is_utf8_invariant_string_loc" in perlapi",

     Size_t  variant_under_utf8_count(const U8* const s,
                                      const U8* const e)

Utility Functions
There are only public API items currently in Utility Functions

Versioning
There are only public API items currently in Versioning

Warning and Dieing

"PL_dowarn"
    The C variable that roughly corresponds to Perl's $^W warning variable. However, $^W is treated as a boolean, whereas "PL_dowarn" is a collection of flag bits.

    On threaded perls, each thread has an independent copy of this variable; each initialized at creation time with the current value of the creating thread's copy.

     U8  PL_dowarn

XS
There are only public API items currently in XS

Undocumented elements
The following functions are currently undocumented. If you use one of them, you may wish to consider creating and submitting documentation for it.

 abort_execution
 add_cp_to_invlist
 _add_range_to_invlist
 alloc_LOGOP
 allocmy
 amagic_cmp
 amagic_cmp_desc
 amagic_cmp_locale
 amagic_cmp_locale_desc
 amagic_is_enabled
 amagic_i_ncmp
 amagic_i_ncmp_desc
 amagic_ncmp
 amagic_ncmp_desc
 append_utf8_from_native_byte
 apply
 ASCII_TO_NEED
 av_arylen_p
 av_extend_guts
 av_iter_p
 av_nonelem
 av_reify
 bind_match
 boot_core_mro
 boot_core_PerlIO
 boot_core_UNIVERSAL
 _byte_dump_string
 cando
 cast_i32
 cast_iv
 cast_ulong
 cast_uv
 check_utf8_print
 ck_anoncode
 ck_backtick
 ck_bitop
 ck_cmp
 ck_concat
 ck_defined
 ck_delete
 ck_each
 ck_entersub_args_core
 ck_eof
 ck_eval
 ck_exec
 ck_exists
 ck_ftst
 ck_fun
 ck_glob
 ck_grep
 ck_index
 ck_isa
 ck_join
 ck_length
 ck_lfun
 ck_listiob
 ck_match
 ck_method
 ck_null
 ck_open
 ck_prototype
 ck_readline
 ck_refassign
 ck_repeat
 ck_require
 ck_return
 ck_rfun
 ck_rvconst
 ck_sassign
 ck_select
 ck_shift
 ck_smartmatch
 ck_sort
 ck_spair
 ck_split
 ck_stringify
 ck_subr
 ck_substr
 ck_svconst
 ck_tell
 ck_trunc
 ck_trycatch
 ckwarn
 ckwarn_d
 closest_cop
 cmpchain_extend
 cmpchain_finish
 cmpchain_start
 cmp_desc
 cmp_locale_desc
 cntrl_to_mnemonic
 coresub_op
 create_eval_scope
 croak_caller
 croak_memory_wrap
 croak_no_mem
 croak_popstack
 csighandler
 csighandler1
 csighandler3
 current_re_engine
 custom_op_get_field
 cv_ckproto_len_flags
 cv_clone_into
 cv_const_sv_or_av
 cvgv_from_hek
 cvgv_set
 cvstash_set
 cv_undef_flags
 cx_dump
 cx_dup
 cxinc
 cx_popblock
 cx_popeval
 cx_popformat
 cx_popgiven
 cx_poploop
 cx_popsub
 cx_popsub_args
 cx_popsub_common
 cx_popwhen
 cx_pushblock
 cx_pusheval
 cx_pushformat
 cx_pushgiven
 cx_pushloop_for
 cx_pushloop_plain
 cx_pushsub
 cx_pushtry
 cx_pushwhen
 cx_topblock
 deb_stack_all
 defelem_target
 delete_eval_scope
 despatch_signals
 die_unwind
 do_aexec
 do_aexec5
 do_eof
 does_utf8_overflow
 do_exec
 do_exec3
 dofile
 do_gvgv_dump
 do_gv_dump
 do_hv_dump
 doing_taint
 do_ipcctl
 do_ipcget
 do_magic_dump
 do_msgrcv
 do_msgsnd
 do_ncmp
 do_open6
 do_open_raw
 do_op_dump
 do_pmop_dump
 do_print
 do_readline
 do_seek
 do_semop
 do_shmio
 do_sv_dump
 do_sysseek
 do_tell
 do_trans
 do_uniprop_match
 do_vecget
 do_vecset
 do_vop
 drand48_init_r
 drand48_r
 dtrace_probe_call
 dtrace_probe_load
 dtrace_probe_op
 dtrace_probe_phase
 dump_all_perl
 dump_indent
 dump_packsubs_perl
 dump_sub_perl
 dump_sv_child
 dump_vindent
 dup_warnings
 emulate_cop_io
 find_first_differing_byte_pos
 find_lexical_cv
 find_runcv_where
 find_script
 foldEQ_latin1
 foldEQ_latin1_s2_folded
 foldEQ_utf8_flags
 _force_out_malformed_utf8_message
 form_alien_digit_msg
 form_cp_too_large_msg
 free_tied_hv_pool
 free_tmps
 get_and_check_backslash_N_name
 get_db_sub
 get_debug_opts
 get_deprecated_property_msg
 getenv_len
 get_hash_seed
 get_invlist_iter_addr
 get_invlist_offset_addr
 get_invlist_previous_index_addr
 get_no_modify
 get_opargs
 get_prop_definition
 get_prop_values
 get_regclass_nonbitmap_data
 get_regex_charset_name
 get_re_arg
 get_re_gclass_nonbitmap_data
 gimme_V
 grok_bin_oct_hex
 grok_bslash_c
 grok_bslash_o
 grok_bslash_x
 gv_check
 gv_fetchmeth_internal
 gv_override
 gv_setref
 gv_stashpvn_internal
 hfree_next_entry
 hv_backreferences_p
 hv_common
 hv_common_key_len
 hv_kill_backrefs
 hv_placeholders_p
 hv_pushkv
 hv_undef_flags
 init_argv_symbols
 init_constants
 init_dbargs
 init_debugger
 init_i18nl10n
 init_i18nl14n
 init_named_cv
 init_uniprops
 _inverse_folds
 invert
 invlist_array
 invlist_clear
 invlist_clone
 invlist_contents
 _invlistEQ
 invlist_extend
 invlist_highest
 invlist_is_iterating
 invlist_iterfinish
 invlist_iterinit
 invlist_iternext
 invlist_lowest
 invlist_max
 invlist_previous_index
 invlist_set_len
 invlist_set_previous_index
 invlist_trim
 _invlist_array_init
 _invlist_contains_cp
 _invlist_dump
 _invlist_intersection
 _invlist_intersection_maybe_complement_2nd
 _invlist_invert
 _invlist_len
 _invlist_search
 _invlist_subtract
 _invlist_union
 _invlist_union_maybe_complement_2nd
 invmap_dump
 io_close
 isFF_OVERLONG
 is_grapheme
 is_invlist
 is_utf8_char_helper
 is_utf8_common
 is_utf8_overlong_given_start_byte_ok
 _is_cur_LC_category_utf8
 _is_in_locale_category
 _is_uni_FOO
 _is_uni_perl_idcont
 _is_uni_perl_idstart
 _is_utf8_FOO
 _is_utf8_perl_idcont
 _is_utf8_perl_idstart
 jmaybe
 keyword
 keyword_plugin_standard
 list
 load_charnames
 localize
 lossless_NV_to_IV
 magic_cleararylen_p
 magic_clearenv
 magic_clearisa
 magic_clearpack
 magic_clearsig
 magic_clear_all_env
 magic_copycallchecker
 magic_existspack

AUTHORS
The autodocumentation system was originally added to the Perl core by Benjamin Stuhl. Documentation is by whoever was kind enough to document their functions.

SEE ALSO
config.h, perlapi, perlapio, perlcall, perlclib, perlfilter, perlguts, perlinterp, perliol, perlmroapi, perlreguts, perlxs