title: Cannot store memcache key
body: <p>I need <code>memcache</code> for store specific configuration keys. I've integrate <code>memcache</code> inside my <code>Settings</code> class, this class is instatiated each time that a request is performed. Infact, in my own framework, all requests are shunt from <code>index.php</code>. So:</p>
  
  <pre><code>index.php -&gt; autoloader (new Settings, new Model, new Controller, etc...) -&gt; logic
  </code></pre>
  
  <p>the <code>Settings</code> class is like this:</p>
  
  <pre><code>include 'config.php'; //contains the `$config` array
  
  class Settings
  {
      private $_config = array();
      private static $_memcache = null;
  
      function __construct()
      {
         self::$_memcache = new Memcache();
         self::$_memcache-&gt;connect('localhost', 11211); //take in the php doc example
  
        $this-&gt;_config = $config;
  
        foreach($config as $item =&gt; $value)
        {
           self::$_memcache-&gt;add($item, $value);
        }
     }
  
     public static function set($name, $value)
     {
        self::$_memcache-&gt;set($name, $value);
     }
  
     public static function get($name)
     {
        return self::$_memcache-&gt;get($name);
     }
  }
  </code></pre>
  
  <p>How you can see I use the <code>method</code> add, in the doc I've read that return false when a key is already setted. The value to set in memcache are taken from my <code>$config</code> array that is included by <code>config.php</code> file.</p>
  
  <p>I also have two method <code>set</code> that should set a specific key, and <code>get</code> that should return a key.</p>
  
  <p>The problem's that each time that this script is executed I get <code>true</code> when I <code>var_dump(self::$_memcache-&gt;add($item, $value));</code>.</p>
  
  <p>I use <code>self</code> for use static method of settings. What am I doing wrong? </p>