Substract 2 datetimes
<p>I need to substract 2 datetimes, I tried a lot of things but nothing seems to work:</p>

<pre><code>$startime = $historial-&gt;getStarttime(); //Datetime
$endtime  = $historial-&gt;getEndtime();   //Datetime
$mytime = $endtime - $startime;
</code></pre>

<p>I also tried with <code>strtotime()</code>, <code>date()</code>...</p>

<p>Any help or clue?</p>
