iOS并发(多线程)

主队列(主线程串行)dispatch_async(dispatch_get_main_queue(), ^{});

全局队列(非主线程并行)dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0),^{});DISPATCH_QUEUE_PRIORITY_HIGHDISPATCH_QUEUE_PRIORITY_DEFAULTDISPATCH_QUEUE_PRIORITY_LOWDISPATCH_QUEUE_PRIORITY_BACKGROUND

自定义队列(非主线程)(串行)dispatch_async(dispatch_queue_create("xxxx",  DISPATCH_QUEUE_SERIAL), ^{});(并行)dispatch_async(dispatch_queue_create("xxxx",  DISPATCH_QUEUE_CONCURRENT), ^{});