如果在三个不同的队列中调用dispatch_sync,有什么区别吗? NSLog(@"this execute in main thread") // via [NSThread isMainThread]
2.
dispatch_sync(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGHisMainThrea
我需要从一个NSData ()块中提取一个dispatch_sync项。dataForFile:(NSString *)fileName { // ... having problem with 'data' var within dispatch_syncdispatch_sync(serialQueue, ^{ if