Default alert view in maps in iphone

I am new to iphone development.I am creating a map application.I want to display the alert "asking for load the current location".To do that should i call a alert method or can i invoke the inbuilt method(if available).And if the ipod touch cannot determine the location it should 开发者_如何转开发display an alert"your location cannot be determined".For this purpose also is there a default alert or i should create an alert.I have added map and core location frameworks.Please help me out.Please guide me.Thanks.

These alerts will appear automatically when the program attempts to use CoreLocation or failed to determine the location.

You don't take action when they click ok. Your program will just start receiving location messages from core location. However if the click Deny then Core Location will throw an error and you must catch that and understand that you won't be getting location data from them.