现象：

A PHP Error was encountered

Severity: Notice

Message: Only variable references should be returned by reference

Filename: core/Common.php

Line Number: 257

参考了下面链接

https://www.jb51.net/article/69548.htm

http://blog.itpub.net/15498/viewspace-2134612/

原代码：

return $_config[0] =& $config;

修改后:

$_config[0] =& $config;return $_config[0];