iOS两个线程间嵌套发送同步消息的demo

// // AppDelegate.h // Sync // // Created by liuhx on 13-2-28. // Copyright (c) 2013年 liuhx. All rights reserved. // #import <UIKit/UIKit.h> @class ViewController; @interface AppDelegate : UIResponder <UIApplicationDelegate> @property (strong, nonatomic) UIWindow *window; @property (strong, nonatomic) ViewController *viewController; @end