Block based notification

gistfile1.h

NSNotificationCenter *nc = [NSNotificationCenter defaultCenter];
[[UIDevice currentDevice] beginGeneratingDeviceOrientationNotifications];
[nc addObserverForName:UIDeviceOrientationDidChangeNotification object:nil 
queue:[NSOperationQueue mainQueue] usingBlock:^(NSNotification *notif){
	UIDeviceOrientation orientation;
	orientation = [[UIDevice currentDevice] orientation];
	if (UIDeviceOrientationIsPortrait(orientation)) {
		NSLog(@"portrait");
	} else {
		NSLog(@"landscape");
	}
}];