Re: tied handle in xs

I have no experience working with tied objects in XS, but I imagine it would be similar to whatever the perl core does.

First lookup what op does the same thing you want to do. In this case, read (called pp_read in C and located in mathoms.c). It delegates to pp_sysread in pp_sys.c.

The definition of this op is in the section following PP(pp_sysread)

The section that handles tied handles is:

    if ((PL_op->op_type == OP_READ || PL_op->op_type == OP_SYSREAD)
        && gv && (io = GvIO(gv)) )
    {
        const MAGIC * mg = SvTIED_mg((SV*)io, PERL_MAGIC_tiedscalar);
        if (mg) {
            SV *sv;
            PUSHMARK(MARK-1);
            *MARK = SvTIED_obj((SV*)io, mg);
            ENTER;
            call_method("READ", G_SCALAR);
            LEAVE;
            SPAGAIN;
            sv = POPs;
            SP = ORIGMARK;
            PUSHs(sv);
            RETURN;
        }
    }
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Re^2: tied handle in xs by Anonymous Monk on Oct 03, 2008 at 05:45 UTC
I have no experience working with tied objects in XS, but I imagine it would be similar to whatever the perl core does. There's better ways, perlXStut: EXAMPLE 9 Passing open files to XSes.	[reply]
Re^3: tied handle in xs by plobsing (Friar) on Oct 03, 2008 at 06:44 UTC
I've read that. It suggests using typemaps for PerlIO objects (my first resort). However, looking at the T_IN and T_INOUT typemaps, they both do `$var = IoIFP(sv_2io($arg))`. That apparently isn't working for spacepille. So I looked for other options.	[reply] [d/l]
Re^4: tied handle in xs by Anonymous Monk on Oct 03, 2008 at 07:45 UTC
It should work, so spacepille must be omitting something.	[reply]
Re^2: tied handle in xs by spacepille (Acolyte) on Oct 04, 2008 at 21:05 UTC
big thank you, it works... `IO io = sv_2io( sv ); PerlIO perlio = IoIFP( io ); if( perlio != NULL ) { PerlIO_read( perlio, ... ); } else { const MAGIC mg = SvTIED_mg( (SV ) io, 'q' ); if( mg != NULL ) { sv = SvTIED_obj( (SV *) io, mg ); // call the READ method with sv as object... } else { Perl_croak( aTHX_ "invalid IO handle" ); } }` [download]	[reply] [d/l]