MonoBehaviour.OnApplicationPause

function OnApplicationPause (pause : boolean) : void

Description

Sent to all game objects when the player pauses.

OnApplicationPause can be a co-routine, simply use the yield statement in the function.

JavaScript
    var paused: boolean;
function OnGUI() {
// Show a message if the game is paused.
if (paused) {
GUI.Label(new Rect(100, 100, 50, 30), "Game paused");
}
}
function OnApplicationPause(pauseStatus: boolean) {
paused = pauseStatus;
}

using UnityEngine;
using System.Collections;

public class example : MonoBehaviour {
public bool paused;
void OnGUI() {
if (paused)
GUI.Label(new Rect(100, 100, 50, 30), "Game paused");

}
void OnApplicationPause(bool pauseStatus) {
paused = pauseStatus;
}
}

import UnityEngine
import System.Collections

class example(MonoBehaviour):

public paused as bool

def OnGUI():
if paused:
GUI.Label(Rect(100, 100, 50, 30), 'Game paused')

def OnApplicationPause(pauseStatus as bool):
paused = pauseStatus