reference.
</p>
<p>
The pre-defined operations are always tried first before deferring to a
metamethod or index table (if any) for the corresponding ctype (except
for <tt>__new</tt>). An error is raised if the metamethod lookup or
index table lookup fails.
</p>

<h3 id="cdata_array">Indexing a cdata object</h3>
<ul>

<li><b>Indexing a pointer/array</b>: a cdata pointer/array can be
indexed by a cdata number or a Lua number. The element address is
computed as the base address plus the number value multiplied