d rotates is accepted, but that alone does <em>not</em> cause
a cdata number output.

</ul>

<h3 id="cdata_comp">Comparisons of cdata objects</h3>
<ul>

<li><b>Pointer comparison</b>: two compatible cdata pointers/arrays
can be compared. The result is the same as an unsigned comparison of
their addresses. <tt>nil</tt> is treated like a <tt>NULL</tt> pointer,
which is compatible with any other pointer type.</li>

<li><b>64&nbsp;bit integer comparison</b>: two cdata numbers, or a
cdata number and a Lua number