NAME

DESCRIPTION

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. (C<< <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

SEE ALSO