yii framework config file log part

                'log'=>array(
                        'class'=>'CLogRouter',
                        'routes'=>array(/**
                                array(
                                        'class'=>'CFileLogRoute',
                                        'levels'=>'error, warning',
                                ),
                ),),**/
                                // uncomment the following to show log messages on web pages
                                array(
                                        'class'=>'CProfileLogRoute',
                                        'enabled'=> YII_DEBUG,
                                        'showInFireBug'=>true,
                                ),
                                array(
                                        'class'=>'CWebLogRoute',
                                        'enabled'=> YII_DEBUG,
                                        'showInFireBug'=>true,
                                ),
                        ),
                ),