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!

Global Variables
    PL_DBsingle
     When Perl is run in debugging mode, with the -d switch, this SV
     is a boolean which indicates whether subs are being sin-
     gle-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".

      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".

      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".

      SV *  PL_DBtrace

    PL_dowarn
     The C variable which corresponds to Perl's $^W warning vari-
     able.

      bool  PL_dowarn

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

      GV*   PL_last_in_gv

    PL_ofs_sv
     The output field separator - $, in Perl space.

      SV*   PL_ofs_sv

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

      SV*   PL_rs

GV Functions
    is_gv_magical
     Returns "TRUE" if given the name of a magical GV.

     Currently only useful internally when determining if a GV
     should be created even in rvalue contexts.

     "flags" is not used at present but available for future exten-
     sion to allow selecting particular classes of magical variable.

      bool  is_gv_magical(char *name, STRLEN len, U32 flags)

IO Functions
    start_glob
     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. Moving it away shrinks
     pp_hot.c; shrinking pp_hot.c helps speed perl up.

      PerlIO* start_glob(SV* pattern, IO *io)

Pad Data Structures
    CvPADLIST
     CV's can have CvPADLIST(cv) set to point to an AV.

     For these purposes "forms" are a kind-of CV, eval""s are too
     (except they're not callable at will and are always thrown away
     after the eval"" is done executing).

     XSUBs don't have CvPADLIST set - dXSTARG fetches values from
     PL_curpad, but that is really the callers pad (a slot of which
     is allocated by every entersub).

     The CvPADLIST AV has does not have AvREAL set, so REFCNT of
     component items is managed "manual" (mostly in op.c) rather
     than normal av.c rules. The items in the AV are not SVs as for
     a normal AV, but other AVs:

     0'th Entry of the CvPADLIST is an AV which represents the
     "names" or rather the "static type information" for lexicals.

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

     During compilation: "PL_comppad_name" is set the the the names
     AV. "PL_comppad" is set the the frame AV for the frame CvDEPTH
     == 1. "PL_curpad" is set the body of the frame AV (i.e. AvAR-
     RAY(PL_comppad)).

     Itterating over the names AV itterates over all possible pad
     items. Pad slots that are SVs_PADTMP (targets/GVs/constants)
     end up having &PL_sv_undef "names" (see pad_alloc()).

     Only my/our variable (SVs_PADMY/SVs_PADOUR) slots get valid
     names. The rest are op targets/GVs/constants which are stati-
     cally allocated or resolved at compile time. These don't have
     names by which they can be looked up from Perl code at run time
     through eval"" like my/our variables can be. Since they can't
     be looked up by "name" but only by their index allocated at
     compile time (which is usually in PL_op->op_targ), wasting a
     name SV for them doesn't make sense.

     The SVs in the names AV have their PV being the name of the
     variable. NV+1..IV inclusive is a range of cop_seq numbers for
     which the name is valid.  For typed lexicals name SV is
     SVt_PVMG and SvSTASH points at the type.

     If SvFAKE is set on the name SV then slot in the frame AVs are
     a REFCNT'ed references to a lexical from "outside".

     If the 'name' is '&' the the corresponding entry in frame AV is
     a CV representing a possible closure. (SvFAKE and name of '&'
     is not a meaningful combination currently but could become so
     if "my sub foo {}" is implemented.)

      AV *  CvPADLIST(CV *cv)

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". (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 subrou-
     tine

SV Manipulation Functions
    report_uninit
     Print appropriate "Use of uninitialized variable" warning

      void  report_uninit()

    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* ptr, U32 size, 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()

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
   perlguts(1),perlapi(1)