dispatch_get_global_queue set flags = 1 , 崩溃

Question

- (void)viewDidLoad {
    [super viewDidLoad];

    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 1), ^{ 
        [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(listenNotification:) name:@"aysNofitication" object:nil];
    });
}

当我设置标志 1 时，代码会崩溃。

崩溃是：线程 1：EXC_BAD_ACCESS（代码=1，地址=0x50）

Answer 1

正如 Sermandurai Subbiah 所说，对于 dispatch_get_global_queue 的标志参数，您不应该使用 0 以外的任何其他内容。 The documentation for dispatch_get_global_queue 清楚地警告我们：

Flags that are reserved for future use. Always specify 0 for this parameter.

dispatch_get_global_queue set flags = 1 , 崩溃

dispatch_get_global_queue set flags = 1 , the crash

grand-central-dispatch

exc-bad-access