不使用CI的时候，我们可以使用 error_reporting(E_ALL); error_reporting(0); 这类的代码来控制报错级别。当然也可以在类中使用这些语句，不过CI自己已经有控制报错级别的机制在里面了。
也许你不会经常打开index.php，但是修改就在这个文件里面：
/*
*---------------------------------------------------------------
* APPLICATION ENVIRONMENT
*---------------------------------------------------------------
*
* You can load different configurations depending on your
* current environment. Setting the environment also influences
* things like logging and error reporting.
*
* This can be set to anything, but default usage is:
*
* development
* testing
* production
*
* NOTE: If you change these, also change the error_reporting() code below
*
*/
define('ENVIRONMENT', 'development');
/*
*---------------------------------------------------------------
* ERROR REPORTING
*---------------------------------------------------------------
*
* Different environments will require different levels of error reporting.
* By default development will show errors but testing and live will hide them.
*/
if (defined('ENVIRONMENT'))
{
switch (ENVIRONMENT)
{
case 'development':
error_reporting(E_ALL);
break;
case 'testing':
case 'production':
error_reporting(0);
break;
default:
exit('The application environment is not set correctly.');
}
}
ENVIRONMENT 就是来控制报错级别的，默认的有三个选项，development testing production，由上面的switch语句控制。代码已经很清楚了，可以根据自己的需求进行相应更改。
