one class instance
<p>is there a way to prevent the instance of the same class in a PHP script?</p>

<pre><code>$user = new User();


$user2 = new User();  // I want to catch another instance of the user class and throw an exception
</code></pre>

<p>I have tried creating a static variable and manipulating it with a static function:</p>

<pre><code>User::instance()
</code></pre>

<p>but that doesn't stop me from doing:</p>

<pre><code>$user = new User();
</code></pre>
