title: PHP json_decode google cloud messaging handle errors
body: <pre><code>{"multicast_id":6500496951237632198,"success":0,"failure":1,"canonical_ids":0,"results":[{"error":"NotRegistered"}]}
  </code></pre>
  
  <p>How to get value "NotRegistered" form this json message.</p>
  
  <p>if print <code>$obj-&gt;failure</code> will get 1.</p>
  
  <p>if print <code>$obj-&gt;results</code> only get Array.</p>