You should give an array of config or an ini config file(see Yaf_Config_Ini) path to Yaf_Application::__construct. Yaf will merge the application configurations and user configurations automatically. The application configurations have prefix "yaf." or "application.". If both "yaf." and "application." exist, "application." will be accepted preferentially. array( "directory" => dirname(__FILE__), "dispatcher" => array( "catchException" => 0, ), "view" => array( "ext" => "phtml", ), ), ); $app = new Yaf_Application($configs); ?> ]]> &Name; &Default; &Changelog; application.directory application.ext "php" application.view.ext "phtml" application.modules "index" application.library application.directory . "/library" application.library.directory application.directory . "/library" application.library.namespace "" application.bootstrap application.directory . "/Bootstrap" . application.ext application.baseUri "" application.dispatcher.defaultRoute application.dispatcher.throwException 1 application.dispatcher.catchException 0 application.dispatcher.defaultModule "index" application.dispatcher.defaultController "index" application.dispatcher.defaultAction "index" application.system &ini.descriptions.title; application.directory string The directory of the application, that is the folder which contains the "controllers", "views", "models", "plugins" folders. This config entry is the only one which doesn't has a default value. You should always define it manually. application.ext string The file ext of the PHP script, used in class autoloading( Yaf_Loader). application.view.ext string The file ext of the view template scripts. application.modules string A comma-separated list of the registered modules, used in the route process, especially while there are more than three segments in the PATH_INFO, Yaf need a way to find out whether the first segment is a module name or not. application.library string The local library directory, see Yaf_Loader and yaf.library. After Yaf 2.1.6, this config entry can be an array. The library path will try to use the items setted in application.library.directory application.library.directory string Alias of application.library. Introduced in Yaf 2.1.6 application.library.namespace string A comma-separated prefix of local library namespace. Introduced in Yaf 2.1.6 application.bootstrap string A absolute path of the Bootstrap class script. application.baseUri string Used to remove a fixed prefix of request uri in route process. Take a example, comes a request with request uri "/prefix/controller/action". if you set application.baseUri to "/prefix", then only "/controller/action" will take as the PATH_INFO in route process. In generally, there is no need to set this value. application.dispatcher.throwException bool If it set to On, Yaf will throw an exception while some error occurring. See also Yaf_Dispatcher::throwException. application.dispatcher.catchException bool If it set to On, Yaf will forward to Error controller/Action while there is an unhandled exception. See also Yaf_Dispatcher::catchException. application.dispatcher.defaultRoute string The default Route, if it is not specificed, Static route will be used as default. See: Yaf_Router::addRoute. application.dispatcher.defaultModule string The default module name, see also Yaf_Dispatcher::setDefaultModule. application.dispatcher.defaultController string The default controller name, see also Yaf_Dispatcher::setDefaultController. application.dispatcher.defaultAction string The default action name, see also Yaf_Dispatcher::setDefaultAction. application.system string Set yaf runtime configure in application.ini, like: application.system.lowcase_path only those PHP_INI_ALL configures can be set in this way