Why's PHP complaining about my register_shutdown_function()?
<p>I try to register a shutdown function to log an fatal error. Nice stuff, if it would work for my class...</p>

<p>Inside a method I do this:</p>

<pre><code>register_shutdown_function(array($this, 'handleFatalError'));
</code></pre>

<p>handleFatalError is not static, and it's public:</p>

<pre><code>public function handleFatalErrors() {
    if(is_null($e = error_get_last()) === false) {
        //mail('your.email@example.com', 'Error from auto_prepend', print_r($e, true));
    }
}
</code></pre>

<p>PHP says:</p>

<blockquote>
  <p>Warning: register_shutdown_function()
  [function.register-shutdown-function]:
  Invalid shutdown callback
  'ErrorManager::handleFatalError'
  passed in  ...</p>
</blockquote>

<p>Why's that an invalid callback?</p>
