e class="code">x</code>
    and whose sign is that of <code class="code">y</code>.  If <code class="code">x</code> is <code class="code">nan</code>, returns <code class="code">nan</code>.
    If <code class="code">y</code> is <code class="code">nan</code>, returns either <code class="code">x</code> or <code class="code">-.&nbsp;x</code>, but it is not
    specified which.</p>
</div>
</div>

<pre><span id="VALsign_bit"><span class="keyword">val</span> sign_bit</span> : <code class="type">float -&gt; bool</co