 <code class="code">c</code> does not occur in <code class="code">s</code> before position <code class="code">i+1</code>.</li>
<li><code>Invalid_argument</code> if <code class="code">i+1</code> is not a valid position in <code class="code">s</code>.</li>
</ul></li>
</ul>
</div>

<pre><span id="VALrindex_from_opt"><span class="keyword">val</span> rindex_from_opt</span> : <code class="type">string -&gt; int -&gt; char -&gt; int option</code></pre><div class="info ">
<div class="info-desc">
<p><code class="cod