error handling

When the display_errors is Off, and the output of the page comes all in the end, or when you're using some template engine or some output buffer function (ob_start()), no output is displayed to the screen! I would like to tell a message to the use in case of failure of the scripy, without giving the information of the kind of error it is. Display a message like: the application has caused an error! the webmaster has been notified by email. And the precise error in the error log, like: Parse error in line .... file .... Is there anythig to do it without setting up a custom error log? thanks Mattia