What is considered the best practice to handle variables stored in a configuration file?
<p>If I use a configuration file to store for example the sitename, database host, etc.. what is the best practice to handle this?</p>

<ol>
<li><code>$sitename="stackoverflow.com";</code> and then setting global $sitename in functions </li>
<li><code>DEFINE(_SITENAME,"stackoverflow.com")</code></li>
<li><code>function vars(){return array(sitename=&gt;"stackoverflow");}</code></li>
<li>?</li>
</ol>

<p>I would love a technical explanation on why should I pick one instead of the other.</p>

<p>Thank you!</p>
