eval(phpcode) 

<"beautiful";
$time = "winter";
 
$str = 'This is a $string $time morning!';
echo $str. "<br />";
 
eval("\$str = \"$str\";");
echo $str;
"background-color: #ccffcc">具体代码片段如下：



if ( ! isset($active_record) OR $active_record == TRUE)
 {
 require_once(BASEPATH.'database/DB_active_rec.php');
 
 if ( ! class_exists('CI_DB'))
 {
  eval('class CI_DB extends CI_DB_active_record { }');
 }
 }
 else
 {
 if ( ! class_exists('CI_DB'))
 {
  eval('class CI_DB extends CI_DB_driver { }');
 }
 }
 
 require_once(BASEPATH.'database/drivers/'.$params['dbdriver'].'/'.$params['dbdriver'].'_driver.php');
 
 // Instantiate the DB adapter
 $driver = 'CI_DB_'.$params['dbdriver'].'_driver';
 $DB = new $driver($params);


以上这篇浅谈PHP eval()函数定义和用法就是小编分享给大家的全部内容了，希望能给大家一个参考，也希望大家多多支持。