static void
iter_<%=c_func%>(na_loop_t *const lp)
{
    size_t   i;
    char    *p1, *p2;
    ssize_t  s1, s2;
    double   x, y;
    <%=struct%> *w = (<%=struct%>*)(lp->opt_ptr);
    <% c_args = get(:postpose) ? "x,y,w" : "w,x,y" %>

    INIT_COUNTER(lp, i);
    INIT_PTR(lp, 0, p1, s1);
    INIT_PTR(lp, 1, p2, s2);

    for (; i--;) {
        GET_DATA_STRIDE(p1,s1,double,x);
        GET_DATA_STRIDE(p2,s2,double,y);
        <%=func_name%>(<%=c_args%>);
    }
}

/*
  @overload <%=name%>(<%=args[1..2].map{|a| a[1]}.join(",")%>)
  @param  [DFloat]   <%=args[1][1]%>
  @param  [DFloat]   <%=args[2][1]%>
  @return [<%=class_name%>]  self

  <%= description %>
*/
static VALUE
<%=c_func(2)%>(VALUE self, VALUE v1, VALUE v2)
{
    <%=struct%> *w;
    ndfunc_arg_in_t ain[2] = {{cDF,0},{cDF,0}};
    ndfunc_t ndf = {iter_<%=c_func%>, STRIDE_LOOP, 2,0, ain,0};

    TypedData_Get_Struct(self, <%=struct%>, &<%=data_type_var%>, w);

    na_ndloop3(&ndf, w, 2, v1, v2);
    return self;
}
