X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=pod%2Fperlintern.pod;h=c9cb5e76985ee3c22438d084500e5724139d5862;hb=351f32542342b92f7303dec0a812c5301714120f;hp=544b87887f9f929bc0adba6455136ab871896044;hpb=bd16a5f0b030a6752676e07b488b3ba891d6e8f7;p=p5sagit%2Fp5-mst-13.2.git diff --git a/pod/perlintern.pod b/pod/perlintern.pod index 544b878..c9cb5e7 100644 --- a/pod/perlintern.pod +++ b/pod/perlintern.pod @@ -10,41 +10,10 @@ Perl interpreter that are documented using Perl's internal documentation format but are not marked as part of the Perl API. In other words, B! -=over 8 - -=item djSP - -Declare Just C. This is actually identical to C, and declares -a local copy of perl's stack pointer, available via the C macro. -See C. (Available for backward source code compatibility with the -old (Perl 5.005) thread model.) - djSP; - -=for hackers -Found in file pp.h - -=item is_gv_magical - -Returns C if given the name of a magical GV. - -Currently only useful internally when determining if a GV should be -created even in rvalue contexts. - -C 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) - -=for hackers -Found in file gv.c - -=item LVRET - -True if this op will be the return value of an lvalue subroutine +=head1 Global Variables -=for hackers -Found in file pp.h +=over 8 =item PL_DBsingle @@ -118,14 +87,34 @@ The input record separator - C<$/> in Perl space. =for hackers Found in file thrdvar.h -=item report_uninit -Print appropriate "Use of uninitialized variable" warning +=back - void report_uninit() +=head1 GV Functions + +=over 8 + +=item is_gv_magical + +Returns C if given the name of a magical GV. + +Currently only useful internally when determining if a GV should be +created even in rvalue contexts. + +C 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) =for hackers -Found in file sv.c +Found in file gv.c + + +=back + +=head1 IO Functions + +=over 8 =item start_glob @@ -139,6 +128,113 @@ Moving it away shrinks pp_hot.c; shrinking pp_hot.c helps speed perl up. =for hackers Found in file doio.c + +=back + +=head1 Pad Data Structures + +=over 8 + +=item 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: +C is set the the the names AV. +C is set the the frame AV for the frame CvDEPTH == 1. +C 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 C is implemented.) + + AV * CvPADLIST(CV *cv) + +=for hackers +Found in file cv.h + + +=back + +=head1 Stack Manipulation Macros + +=over 8 + +=item djSP + +Declare Just C. This is actually identical to C, and declares +a local copy of perl's stack pointer, available via the C macro. +See C. (Available for backward source code compatibility with the +old (Perl 5.005) thread model.) + + djSP; + +=for hackers +Found in file pp.h + +=item LVRET + +True if this op will be the return value of an lvalue subroutine + +=for hackers +Found in file pp.h + + +=back + +=head1 SV Manipulation Functions + +=over 8 + +=item report_uninit + +Print appropriate "Use of uninitialized variable" warning + + void report_uninit() + +=for hackers +Found in file sv.c + =item sv_add_arena Given a chunk of memory, link it to the head of the list of arenas, @@ -179,6 +275,7 @@ heads and bodies within the arenas must already have been freed. =for hackers Found in file sv.c + =back =head1 AUTHORS