de>.
    Raise <code class="code"><span class="constructor">Not_found</span></code> if <code class="code">c</code> does not occur in <code class="code">s</code> after position <code class="code">i</code>.</p>
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<pre><span id="VALindex_from_opt"><span class="keyword">val</span> index_from_opt</span> : <code class="type">bytes -&gt; int -&gt; char -&gt; int option</code></pre><div class="info ">
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<p><code class="code">index_from&nbsp;_opts&nbsp;i&nbsp;c</code> returns the i