ios多线程操作（六）—— GCD全局队列与主队列

dispatch_queue_t q = dispatch_get_global_queue(long identifier, unsigned long flags)

dispatch_queue_t q = dispatch_get_global_queue(0, 0);

 dispatch_queue_t q = dispatch_get_global_queue(0, 0);
    // 2. 异步执行
    for (int i = 0; i < 10; ++i) {
        dispatch_async(q, ^{
            NSLog(@"%@ %d", [NSThread currentThread], i);
        });
    }
    NSLog(@"come here");

// 1. 队列
    dispatch_queue_t q = dispatch_get_global_queue(0, 0);
   
    // 2. 任务
    void (^task)() = ^ {
        dispatch_sync(q, ^{
            NSLog(@"Login %@", [NSThread currentThread]);
        });
        dispatch_async(q, ^{
            NSLog(@"Download A %@", [NSThread currentThread]);
        });
        dispatch_async(q, ^{
            NSLog(@"Download B %@", [NSThread currentThread]);
        });
    };
   
    // 3. 异步执行 task
    dispatch_async(q, task);

 dispatch_queue_t q = dispatch_get_main_queue();

dispatch_queue_t q = dispatch_get_main_queue();
   
    // 2. 异步执行
    for (int i = 0; i < 10; ++i) {
        dispatch_async(q, ^{
            NSLog(@"%@ - %d", [NSThread currentThread], i);
        });
    }
    NSLog(@"线程休眠1s");
    [NSThread sleepForTimeInterval:1.0];
    NSLog(@"come here - %@",[NSThread currentThread]);

// 1.队列
    dispatch_queue_tq = dispatch_get_main_queue();
    NSLog(@"now I'm here");
    // 2. 同步执行
    dispatch_sync(q, ^{
        NSLog(@"%@", [NSThreadcurrentThread]);
    });
    NSLog(@"come here");

 // 全局队列
    dispatch_queue_t q = dispatch_get_global_queue(0, 0);
    // 任务
    void (^task)() = ^ {
        NSLog(@"%@", [NSThread currentThread]);
       // 主队列上执行同步任务
        dispatch_sync(dispatch_get_main_queue(), ^{
            NSLog(@"come here %@", [NSThread currentThread]);
        });
       
        NSLog(@"hahaha %@", [NSThread currentThread]);
    };
   
    // 异步执行任务
    dispatch_async(q, task);
    NSLog(@"now i'm here - %@",[NSThread currentThread]);