or">Invalid_argument</span> <span class="string">"output"</span></code> if <code class="code">pos</code> and <code class="code">len</code> do not
   designate a valid range of <code class="code">buf</code>.<br>
</div>

<pre><span id="VALoutput_substring"><span class="keyword">val</span> output_substring</span> : <code class="type"><a href="Pervasives.html#TYPEout_channel">out_channel</a> -&gt; string -&gt; int -&gt; int -&gt; unit</code></pre><div class="info ">
Same as <code class="code">output</code> but 