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;
        }
    }

[download]

In reply to Re: tied handle in xs by plobsing
in thread tied handle in xs by spacepille

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.