x struct */
result-&gt;hdr.resetfn   = (arg_resetfn*)resetfn;         /* ptr to resetfn callback */
result-&gt;hdr.scanfn    = (arg_scanfn*)scanfn;           /* ptr to scanfn callback */
result-&gt;hdr.checkfn   = (arg_checkfn*)checkfn;         /* ptr to checkfn callback */
result-&gt;hdr.errorfn   = (arg_errorfn*)errorfn;         /* ptr to errorfn callback */
result-&gt;hdr.priv      = result + 1;                    /* ptr to private data */ </PRE><P STYLE="margin-bottom: 0.51cm">
The custom <I>arg_xxx</I>