iOS -多读单写的demo

• 读写锁
  

//
//  ViewController.m
//  多读单写Demo
//
//  Created by Jason on 2019/3/20.
//  Copyright © 2019 友邦创新资讯. All rights reserved.
//

#import "ViewController.h"
#import <pthread.h>

@interface ViewController ()
@property (nonatomic,assign)pthread_rwlock_t lock;

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    pthread_rwlock_init(&_lock,NULL);
    for (int i = 0; i< 10; i++) {
        dispatch_async(dispatch_get_global_queue(0, 0), ^{
            [self read];
        });
        
        dispatch_async(dispatch_get_global_queue(0, 0), ^{
            [self write];
        });
    }
}

- (void)read {
    pthread_rwlock_rdlock(&_lock);
    NSLog(@"read----");
    pthread_rwlock_unlock(&_lock);
}

- (void)write {
    pthread_rwlock_wrlock(&_lock);
    NSLog(@"write----");
    pthread_rwlock_unlock(&_lock);
}

- (void)dealloc {
    pthread_rwlock_destroy(&_lock);
}
@end

• 栅栏操作

//
//  ViewController.m
//  多读单写Demo
//
//  Created by Jason on 2019/3/20.
//  Copyright © 2019 友邦创新资讯. All rights reserved.
//

#import "ViewController.h"
#import <pthread.h>

@interface ViewController ()
@property (nonatomic,assign)pthread_rwlock_t lock;

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    //必须使用自己创建的并发队列,全局队列没有效果
    dispatch_queue_t queue = dispatch_queue_create("queue", DISPATCH_QUEUE_CONCURRENT);
    for (int i = 0; i < 10; i++) {
        dispatch_async(queue, ^{
            [self read];
        });
        dispatch_async(queue, ^{
            [self read];
        });
        dispatch_barrier_async(queue, ^{
            [self write];
        });
    }
}

- (void)readWrite{
    pthread_rwlock_init(&_lock,NULL);
    for (int i = 0; i< 10; i++) {
        dispatch_async(dispatch_get_global_queue(0, 0), ^{
            [self read];
        });
        
        dispatch_async(dispatch_get_global_queue(0, 0), ^{
            [self write];
        });
    }
    
}

- (void)read {
    pthread_rwlock_rdlock(&_lock);
    NSLog(@"read----");
    sleep(1);
    pthread_rwlock_unlock(&_lock);
}

- (void)write {
    pthread_rwlock_wrlock(&_lock);
    NSLog(@"write----");
    sleep(1);
    pthread_rwlock_unlock(&_lock);
}

- (void)dealloc {
    pthread_rwlock_destroy(&_lock);
}
@end