Location service disabled message default not showing in iPhone

In my app the CLLocationManager is used to get the current user location. If the GPS is disabled by the user, then I'm expecting the default alert from apple aski开发者_C百科ng to turn on the GPS services and giving an option to navigate to the settings page.

I'm not getting this alert even for the for the first time I launch the app.

Once the default GPS unavailable alert is shown then it will be showed for that app only after a certain period of time. I'm not sure about that time interval.