OC 线程操作 - GCD快速迭代

最新推荐文章于 2022-01-30 21:10:56 发布

转载最新推荐文章于 2022-01-30 21:10:56 发布 · 47 阅读

CC 4.0 BY-SA版权

原文链接：http://www.cnblogs.com/qingzZ/p/9237408.html

本文详细介绍了使用GCD (Grand Central Dispatch) 进行快速迭代的方法。通过对比主线程操作与GCD的不同表现，展示了如何利用GCD进行高效并发处理。文章通过具体的代码示例解释了dispatch_apply函数的应用场景及其在并发队列中的表现。

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- (void)forDemo{
    //全都是在主线程操作的
    for (NSInteger i = 0; i<10; i++) {
        NSLog(@"--%@", [NSThread currentThread]);
    }
    
    /*
     2018-06-27 11:33:44.226664+0800 5线程操作-GCD-快速迭代[7715:77291] --<NSThread: 0x60800006a9c0>{number = 1, name = main}
     2018-06-27 11:33:44.226845+0800 5线程操作-GCD-快速迭代[7715:77291] --<NSThread: 0x60800006a9c0>{number = 1, name = main}
     2018-06-27 11:33:44.227048+0800 5线程操作-GCD-快速迭代[7715:77291] --<NSThread: 0x60800006a9c0>{number = 1, name = main}
     2018-06-27 11:33:44.227711+0800 5线程操作-GCD-快速迭代[7715:77291] --<NSThread: 0x60800006a9c0>{number = 1, name = main}
     2018-06-27 11:33:44.227796+0800 5线程操作-GCD-快速迭代[7715:77291] --<NSThread: 0x60800006a9c0>{number = 1, name = main}
     2018-06-27 11:33:44.227927+0800 5线程操作-GCD-快速迭代[7715:77291] --<NSThread: 0x60800006a9c0>{number = 1, name = main}
     2018-06-27 11:33:44.227986+0800 5线程操作-GCD-快速迭代[7715:77291] --<NSThread: 0x60800006a9c0>{number = 1, name = main}
     2018-06-27 11:33:44.228046+0800 5线程操作-GCD-快速迭代[7715:77291] --<NSThread: 0x60800006a9c0>{number = 1, name = main}
     2018-06-27 11:33:44.228111+0800 5线程操作-GCD-快速迭代[7715:77291] --<NSThread: 0x60800006a9c0>{number = 1, name = main}
     2018-06-27 11:33:44.228165+0800 5线程操作-GCD-快速迭代[7715:77291] --<NSThread: 0x60800006a9c0>{number = 1, name = main}
     */
}

-(void)GCD_apply{
    
    
    /**
     参数1：size_t iterations 便利次数
     参数1：dispatch_queue_t  _Nonnull queue 队列：只能穿进去并发队列，主队列 会死锁 ，串行队列和for循环一样效果在主队列，
     参数1：<#^(size_t)block#> ^(size_t 索引) {
     
     }
     
      主队列也会参与这个操作， 并发执行
     */
    dispatch_apply(10, dispatch_get_global_queue(0, 0), ^(size_t index) {
        NSLog(@"dispatch_get_global_queue ---- %zd--%@", index,[NSThread currentThread]);
    });
    
    
    dispatch_queue_t queue = dispatch_queue_create("并发", DISPATCH_QUEUE_CONCURRENT);
    dispatch_apply(10, queue, ^(size_t index) {
        NSLog(@"DISPATCH_QUEUE_CONCURRENT ---- %zd--%@", index,[NSThread currentThread]);
    });
    
    /*
     2018-06-27 11:41:46.924361+0800 5线程操作-GCD-快速迭代[7877:85649] 0--<NSThread: 0x608000074ac0>{number = 1, name = main}
     2018-06-27 11:41:46.924467+0800 5线程操作-GCD-快速迭代[7877:85688] 2--<NSThread: 0x60400007de40>{number = 4, name = (null)}
     2018-06-27 11:41:46.924468+0800 5线程操作-GCD-快速迭代[7877:85691] 3--<NSThread: 0x60c000465cc0>{number = 5, name = (null)}
     2018-06-27 11:41:46.924469+0800 5线程操作-GCD-快速迭代[7877:85690] 1--<NSThread: 0x608000265a00>{number = 3, name = (null)}
     2018-06-27 11:41:46.924526+0800 5线程操作-GCD-快速迭代[7877:85649] 4--<NSThread: 0x608000074ac0>{number = 1, name = main}
     2018-06-27 11:41:46.924554+0800 5线程操作-GCD-快速迭代[7877:85688] 5--<NSThread: 0x60400007de40>{number = 4, name = (null)}
     2018-06-27 11:41:46.924568+0800 5线程操作-GCD-快速迭代[7877:85691] 6--<NSThread: 0x60c000465cc0>{number = 5, name = (null)}
     2018-06-27 11:41:46.924602+0800 5线程操作-GCD-快速迭代[7877:85649] 8--<NSThread: 0x608000074ac0>2018-06-27 11:41:46.924639+0800 5线程操作-GCD-快速迭代[7877:85688] 9--<NSThread: 0x60400007de40>{number = 4, name = (null)}
     {number = 1, name = main}
     2018-06-27 11:41:46.924604+0800 5线程操作-GCD-快速迭代[7877:85690] 7--<NSThread: 0x608000265a00>{number = 3, name = (null)}
     */
}