学习GCD 之前,先来了解 GCD 中两个核心概念:任务和队列。 任务:就是执行操作的意思,换句话说就是你在线程中执行的那段代码。在 GCD 中是放在 block 中的。执行任务有两种方式:同步执行(sync)和异步执行(async)。两者的主要区别是:是否等待队列的任务执行结束,以及是否具备开启新线程的能力。 同步执行(sync): ...
GCD 提供了同步执行任务的创建方法dispatch_sync和异步执行任务创建方法dispatch_async。 // 同步执行任务创建方法dispatch_sync(queue, ^{// 这里放同步执行任务代码});// 异步执行任务创建方法dispatch_async(queue, ^{// 这里放异步执行任务代码}); 虽然使用 GCD 只需两步,但是既然我们有两种队列(串行队列/并发...
2018-02-23 20:48:26.316956+0800 YSC-GCD-demo[20188:5059274] 3---<NSThread: 0x600000079d80>{number = 4, name = (null)} 2018-02-23 20:48:28.320660+0800 YSC-GCD-demo[20188:5059273] 4---<NSThread: 0x600000079e00>{number = 3, name = (null)} 2018-02-23 20:48:28.320649+0800 YSC...
/** * 队列组 dispatch_group_enter、dispatch_group_leave */ - (void)groupEnterAndLeave { NSLog(@"currentThread---%@",[NSThread currentThread]); // 打印当前线程 NSLog(@"group---begin"); dispatch_group_t group = dispatch_group_create(); dispatch_queue_t queue = dispatch_get_global_queu...
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After schedulingstreamwith a run loop, its client (set with CFReadStreamSetClient) is notified when various events happen with the stream, such as when it finishes opening, when it has bytes available, and when an error occurs. A stream can be scheduled with multiple run loops and run loop...
Gasket is the structure of a double sealing gasket and has a signal hole. When the medium leaks first, it can be released through the signal port and solve the problem in advance, so as not to cause the mixing of the two medi...
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Prospects for testing the GCDM model (the graviton model of dark energy where G stands for gravitons) and comparison with the ΛCDM model are discussed. Keywords: dark energy; supernova observations; virtual gravitons Citation: Marochnik, L.S.; Usikov, D.A. Dark Energy from Virtual ...
A 48-Year-Old Man With Fever and Abdominal Pain of One Day DurationYu, MaryTadin, DavidConrad, Erich J.Lopez, Fred A.Journal of the Louisiana State Medical Society