code: public function getLoginStartUrl($redirecturl) {
  		$credentials = array(
  			'identifier' => $this->options['consumer_key'],
  			'secret' => $this->options['consumer_secret'],
  			'callback_uri' => $redirecturl
  		);
  
  		$server = new \League\OAuth1\Client\Server\Xing($credentials);
  		
  		$this->temp_credentials = $server->getTemporaryCredentials();
      
  		return $server->getAuthorizationUrl($this->temp_credentials);
  	}
docs: Returns Xing login start auth process
  
  @param string $redirecturl URL where to redirect after login complete