dispatch_barrier_async函数的作用

最新推荐文章于 2025-04-13 11:09:43 发布

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最新推荐文章于 2025-04-13 11:09:43 发布

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原文链接：http://www.cnblogs.com/xwoder/p/6017886.html

版权

代码：

dispatch_queue_t queue = dispatch_queue_create("queue", DISPATCH_QUEUE_CONCURRENT);

dispatch_async(queue, ^{
    NSLog(@"Before Barrier Block - 1");
});
dispatch_async(queue, ^{
    NSLog(@"Before Barrier Block - 2");
});
dispatch_async(queue, ^{
    NSLog(@"Before Barrier Block - 3");
});
dispatch_async(queue, ^{
    NSLog(@"Before Barrier Block - 4");
});
dispatch_async(queue, ^{
    NSLog(@"Before Barrier Block - 5");
});

dispatch_barrier_async(queue, ^{
    NSLog(@"Barrier Block");
});

dispatch_async(queue, ^{
    NSLog(@"After Barrier Block - 1");
});
dispatch_async(queue, ^{
    NSLog(@"After Barrier Block - 2");
});
dispatch_async(queue, ^{
    NSLog(@"After Barrier Block - 3");
});
dispatch_async(queue, ^{
    NSLog(@"After Barrier Block - 4");
});
dispatch_async(queue, ^{
    NSLog(@"After Barrier Block - 5");
});

可能的输出：

Before Barrier Block - 1
Before Barrier Block - 2
Before Barrier Block - 3
Before Barrier Block - 5
Before Barrier Block - 4
Barrier Block
After Barrier Block - 1
After Barrier Block - 3
After Barrier Block - 2
After Barrier Block - 5
After Barrier Block - 4

备注：

dispatch_barrier_async用于在同一个并发队列中，同步多个并发操作

转载于:https://www.cnblogs.com/xwoder/p/6017886.html