iOS GCD使用整理

自己进行一个复习整理

1.最简单的用法

全局并行

dispatch_async(dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{

//code

});

2；

dispatch_queue_t queue = dispatch_queue_create("cstlab.hj", DISPATCH_QUEUE_SERIAL);  //串行

dispatch_queue_t queue = dispatch_queue_create("cstlab.hj", DISPATCH_QUEUE_CONCURRENT); //并行

dispatch_async(queue, ^{ //异步

//code

});

dispatch_sync(queue, ^{ //同步

//code

});

3；延时

dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(1.0 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{

//code

});

4; dispatch group

dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);

dispatch_group_t group = dispatch_group_create();

dispatch_group_async(group, queue, ^{

NSLog(@"block0-%@",[NSThread currentThread]);

});

dispatch_group_async(group, queue, ^{

NSLog(@"block1-%@",[NSThread currentThread]);

});

dispatch_group_notify(group, dispatch_get_main_queue(), ^{

NSLog(@"block3-%@",[NSThread currentThread]);

});

5; dispatch_barrier_async

dispatch_queue_t queue = dispatch_queue_create("cstlab.hj", DISPATCH_QUEUE_CONCURRENT);

dispatch_async(queue, ^{

NSLog(@"1---%@",[NSThread currentThread]);

});

dispatch_async(queue, ^{

NSLog(@"2---%@",[NSThread currentThread]);

});

dispatch_async(queue, ^{

NSLog(@"3---%@",[NSThread currentThread]);

});

dispatch_barrier_async(queue, ^{

NSLog(@"barrier---%@",[NSThread currentThread]);

});

dispatch_async(queue, ^{

NSLog(@"4---%@",[NSThread currentThread]);

});

dispatch_async(queue, ^{

NSLog(@"5---%@",[NSThread currentThread]);

});

6;dispatch_apply,多次执行

dispatch_apply(10, dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^(size_t index) {

NSLog(@"%zu-%@",index,[NSThread currentThread]);

});

7;暂停和恢复

dispatch_suspend(queue);

dispatch_resume(queue);

8; dispatch_semaphore_t

dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);

dispatch_semaphore_t semaphore = dispatch_semaphore_create(1);

NSMutableArray *array = [NSMutableArray array];

for (NSInteger i = 0; i <= 100; i++) {

dispatch_async(queue, ^{

dispatch_semaphore_wait(semaphore, DISPATCH_TIME_FOREVER);

[array addObject:[NSNumber numberWithInteger:i]];

dispatch_semaphore_signal( semaphore);

});

}

9；once

static dispatch_once_t pred;

dispatch_once(&pred, ^{

//code

});

10；还有一个dispatch I/O改天介绍