php中变量引用&不可与global共同使用

class Ci {

	private static $instance = NULL;
        public $name = ‘hello‘;
        public $load = null;

        public function __construct()
        {
        	self::$instance = &$this;
        	$this->load = new Load;
        	mlog(self::$instance, __LINE__);
			//other code ....
			$this->name = ‘my name‘;
        }	

	public static function &getInstance()
	{
		return self::$instance;
	}
    }

    class My extends Ci{

        public function __construct()
        {
		parent::__construct();
		$this->model = new Model;
        }
    }
    class Model {

	public function __construct() 
	{
		$this->name = _get(); // null
		mlog("success, and model->name = {$this->name}", __LINE__);
	}
　　}
　　class Load {

	public $name = ‘I am Load class‘;

	public function getName() 
	{
		return $this->name;
	}
　　}

    $CI =& get_instance();
    // mlog($CI->name); //hello
    // mlog($CI->load->getName()); //I am Load class
    mlog($CI, __LINE__);
　　$CI = new My;
　　mlog($CI, __LINE__);
	

　　function _get() 
　　{
	//call static variables
	global $CI; //non-boject
	//return $CI->load->name(); // 500
	return $CI->name; //notice
　　}

　　function &get_instance()
　　{
	return Ci::getInstance();
　　}

　　function mlog($content, $line = __LINE__,$display = true)
　　{
	$next_line = "<br />";
	if (php_sapi_name() === ‘cli‘) {
	　　$init = ‘‘;
	　　$next_line = "\n";
	} 
	if ($display) {
	　　echo $init;
	　　echo "in line: $line" . $next_line;
	　　print_r($content);
	　　echo $next_line;
	}
　　}

<?php
    $CI =& get_instance();

    function demo() 
    {
         global $CI;
         //return $CI->mehton;          //notice
         //return $CI->class->method;//500   
    }