php判断是否引入某文件

 1 /* 判断是否引入了公共文件demo.php */
 2 $include_files = get_included_files();
 3 $include_files_exist = 0 ;
 4 foreach($include_files as $include_files_val){
 5     if(strpos($include_files_val,‘demo.php‘) !== false ){
 6         $include_files_exist = 1;
 7     }
 8 }
 9 if($include_files_exist != 1){
10     include_once(‘demo.php‘);
11 }

get_included_files();

strpos()

include_once();