PERLINTERN(1)

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 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".

            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 variable.

            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 extension 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. AvARRAY(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 statically 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 subroutine

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)