Track the abnormal calling process in php

     try{
        	$CI =& get_instance();
        	$ct = $CI->$key ;
        	throw new  Exception($key);
        } catch (Exception $E) {
        	echo $E->getTraceAsString();
        }
		
		

The above introduces the calling process of tracking exceptions in PHP, including aspects of the process. I hope it will be helpful to friends who are interested in PHP tutorials.