nginx环境下CodeIgniter会出现一些问题！
1、数据库驱动连接失败!
出现如下问题：
A PHP Error was encountered Severity: Warning Message: mysqli::real_connect(): (HY000/2002): No such file or directory Filename: mysqli/mysqli_driver.php
解决方法：
这个问题是php.ini配置的问题。
默认以下配置为空,将以下三个选项设置成你mysql.sock对应的目录就可以解决了。（以下配置为mac下）
mysql.default_socket = /tmp/mysql.sock
pdo_mysql.default_socket= /tmp/mysql.sock
mysqli.default_socket =/tmp/mysql.sock
2、出现Only variable references should be returned by reference报错
A PHP Error was encountered
Severity: Notice
Message: Only variable references should be returned by reference
Filename: core/Common.php
Line Number: 257
解决方法：
原代码：
return $_config[0] =& $config;
修改后:
$_config[0] =& $config;
return $_config[0];
3、session报错
A PHP Error was encountered
Severity: Warning
Message: mkdir(): Invalid path
Filename: drivers/Session_files_driver.php
Line Number: 117
解决方法：
以ci 3.0为例：
将config配置文件中 将sess_save_path改为如下
$config['sess_save_path'] = FCPATH.'public/sess_save_path';