/span> : <code class="type">string -&gt; string</code></pre><div class="info ">
<div class="info-desc">
<p>Return the value associated to a variable in the process
   environment. Raise <code class="code"><span class="constructor">Not_found</span></code> if the variable is unbound.</p>
</div>
</div>

<pre><span id="VALgetenv_opt"><span class="keyword">val</span> getenv_opt</span> : <code class="type">string -&gt; string option</code></pre><div class="info ">
<div class="info-desc">
<p>Return the value assoc