catenates s1 and s2 (<code class="code">s1&nbsp;^&nbsp;s2</code>).</p>
</div>
<ul class="info-attributes">
<li><b>Since</b> 4.13.0</li>
<li><b>Raises</b> <code>Invalid_argument</code> if the result is longer than
    <a href="Sys.html#VALmax_string_length"><code class="code"><span class="constructor">Sys</span>.max_string_length</code></a> bytes.</li>
</ul>
</div>
<h2 id="predicates">Predicates and comparisons</h2>
<pre><span id="VALequal"><span class="keyword">val</span> equal</span> : <code class="type"><