 an error.
Even incompatible pointers can be compared for equality by address. Any
other incompatible comparison (also with non-cdata objects) treats the
two sides as unequal.</li>

</ul>

<h3 id="cdata_key">cdata objects as table keys</h3>
<p>
Lua tables may be indexed by cdata objects, but this doesn't provide
any useful semantics &mdash; <b>cdata objects are unsuitable as table
keys!</b>
</p>
<p>
A cdata object is treated like any other garbage-collected object and
is hashed and compared by its address f