Unity raises this event when the Player application is quitting.
Add an event handler to this event to receive a notification that the application is quitting.
Note: This will not fire if the Player is forced to quit or if there is a crash. This event is raised when the quitting process cannot be cancelled.
iOS applications are usually suspended and do not quit. You should tick "Exit on Suspend" in Player settings for iOS builds to cause the game to quit and not suspend, otherwise you may not see this call. If "Exit on Suspend" is not ticked then you will see calls to OnApplicationPause instead.
On Windows Store Apps and Windows Phone 8.1 there's no application quit event, consider using OnApplicationFocus event when focusStatus equals false.
To prevent the player application from quitting look at the Application.wantsToQuit event.
using UnityEngine;
public class PlayerQuitExample { static void Quit() { Debug.Log("Quitting the Player"); }
[RuntimeInitializeOnLoadMethod] static void RunOnStart() { Application.quitting += Quit; } }
See Also: Application.wantsToQuit.