Global Variable


Posted when the app receives a warning from the operating system about low memory availability.


const NSNotificationName UIApplicationDidReceiveMemoryWarningNotification;


This notification does not contain a userInfo dictionary.

See Also

Responding to Environment Changes

- applicationProtectedDataDidBecomeAvailable:

Tells the delegate that protected files are available now.

- applicationProtectedDataWillBecomeUnavailable:

Tells the delegate that the protected files are about to become unavailable.

- applicationDidReceiveMemoryWarning:

Tells the delegate when the app receives a memory warning from the system.

- applicationSignificantTimeChange:

Tells the delegate when there is a significant change in the time.


Posted when the protected files become available for your code to access.


Posted shortly before protected files are locked down and become inaccessible.


Posted when there is a significant change in time, for example, change to a new day (midnight), carrier time update, and change to or from daylight savings time.

Beta Software

This documentation contains preliminary information about an API or technology in development. This information is subject to change, and software implemented according to this documentation should be tested with final operating system software.

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