第3月第19天 cxx_destruct dispatch_get_main_queue()死锁

1.

http://blog.jobbole.com/65028/

2.

- (void)viewDidLoad {
    [super viewDidLoad];

    NSLog(@"");
    dispatch_sync(dispatch_get_main_queue(), ^{
        NSLog(@"");
    });
    NSLog(@"");
}

答案：输出1之后程序死锁

http://blog.sunnyxx.com/2014/03/06/ios_exam_0_key/