n the above example, <tt>v</tt> is a name that's used for the object.  However,
underneath the covers, there's a pointer to a raw C structure.  This can be obtained
by looking at the <tt>-this</tt> attribute.  For example:
</p>

<div class="code">
<pre>
% puts [v cget -this]
_88e31408_p_Vector
</pre>
</div>

<p>
Further details about the relationship between the Tcl and the underlying C structure
are covered a little later.
</p>

<p>
<tt>const</tt> members of a structure are read-only. Data members
can also