Objective-c and Xcode strange behavior

Question

In xcode 4.3.1, target iPad 5.1 simulator

• create a single view app

• use ARC, don't use Storyboard

• in ViewController.h

   #import <UIKit/UIKit.h> @interface ViewController : UIViewController { NSObject *anObject; NSObject *anotherObject; } -(void) makeObjects; @end 

• in ViewController.m add

   -(void) makeObjects{ anObject = [[NSObject alloc] init]; anotherObject = [[NSObject alloc] init]; int a = 1; } 

• in AppDelegate.m add a line

   - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions: (NSDictionary *)launchOptions { self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]]; // Override point for customization after application launch. self.viewController = [[ViewController alloc] initWithNibName:@"ViewController" bundle:nil]; self.window.rootViewController = self.viewController; [self.viewController makeObjects]; // ADD THIS LINE <-------- [self.window makeKeyAndVisible]; return YES; } 

• in ViewController.m, set a breakpoint at

   anObject = [[NSObject alloc] init]; 

• run

• step over breakpoint
• anObject = 0x00000000, anotherObject is set!

Answer 1

Are you using the LLDB debugger? Currently it doesn't give you correct values on iVars in the simulator. Switch back to GDB and you'll find the correct values reported. I discovered this behavior here: UIViewController subclass can't assign instance variable .

And yes, I reported a bug. I got a response back from Apple stating it is a known issue.