思考如下实现以下场景？
上面的场景就是典型的“多读单写”，经常用于文件等数据的读写操作，iOS的实现方案有
#import "ViewController.h" #import <pthread.h> @interface ViewController () @property (assign, nonatomic) pthread_rwlock_t lock; @end @implementation ViewController - (void)viewDidLoad { [super viewDidLoad]; // 初始化锁 pthread_rwlock_init(&_lock, NULL); dispatch_queue_t queue = dispatch_get_global_queue(0, 0); for (int i = 0; i < 10; i++) { dispatch_async(queue, ^{ [self read]; }); dispatch_async(queue, ^{ [self write]; }); } } - (void)read { //读锁 pthread_rwlock_rdlock(&_lock); sleep(1); NSLog(@"%s", __func__); pthread_rwlock_unlock(&_lock); } - (void)write { //写锁 pthread_rwlock_wrlock(&_lock); sleep(1); NSLog(@"%s", __func__); pthread_rwlock_unlock(&_lock); } // pthread_rwlock_destroy 是pthread锁，要销毁 - (void)dealloc { pthread_rwlock_destroy(&_lock); }
这个函数传入的并发队列 必须是自己通过dispatch_queue_create创建的
如果传入的是一个串行队列或者是全局的并发队列，那这个函数便等同于dispatch_async 函数的效果，起不到栅栏的作用
#import "ViewController.h" #import <pthread.h> @interface ViewController () @property (strong, nonatomic) dispatch_queue_t queue; @end @implementation ViewController - (void)viewDidLoad { [super viewDidLoad]; self.queue = dispatch_queue_create("rw_queue", DISPATCH_QUEUE_CONCURRENT); for (int i = 0; i < 10; i++) { dispatch_async(self.queue, ^{ [self read]; }); dispatch_async(self.queue, ^{ [self read]; }); dispatch_async(self.queue, ^{ [self read]; }); dispatch_barrier_async(self.queue, ^{ [self write]; }); } } - (void)read { sleep(1); NSLog(@"read"); } - (void)write { sleep(1); NSLog(@"write"); } @end
上面就是两种常用的iOS 读写安全操作，欢迎指正！！！
原文：https://www.cnblogs.com/guohai-stronger/p/12906137.html