NSLock简单应用

#import "AppDelegate.h"

@interface AppDelegate ()

@end

@implementation AppDelegate

-(void)dealloc{
    
    [_window release];
    [super dealloc];
}


- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    self.window = [[UIWindow alloc]initWithFrame:[UIScreen mainScreen].bounds];
    self.window.backgroundColor = [UIColor blackColor];
    
    [self.window makeKeyAndVisible];
    
    [_window release];
    
    //线程互斥  线程没有自己独立的栈堆空间，都是使用进程内部的内存空间，所以有可能多个线程同时访问同一块内存，这时就会出问题，针对多线程访问共享资源是就会采用线程互斥方式，加线程锁
    NSLock *lk = [[NSLock alloc]init];
    
    NSThread *thread1 = [[NSThread alloc]initWithTarget:self selector:@selector(therad:) object:lk];
    
    thread1.name = @"1号窗口";
    
    [thread1 start];
    
    
    
    NSThread *therad2 = [[NSThread alloc]initWithTarget:self selector:@selector(therad:) object:lk];
    
    therad2.name = @"2号窗口" ;
    
//    therad2.threadPriority = 0.9 ;
    
    [therad2 start];
    
    
    
    NSThread *therad3 = [[NSThread alloc]initWithTarget:self selector:@selector(therad:) object:lk];
    
    therad3.name = @"3号窗口" ;
    
    therad3.threadPriority = 1 ;
    
    [therad3 start];
    
    
    
    
    
    
    return YES;
}


//模拟售票
-(void)therad:(id)object{
    
    NSLock *lk = (NSLock *)object ;
    
    //票数100张
    static int number = 100 ;
    
    while (1) {
        
        // 加线程锁，提高数据访问的安全性
        [lk lock];
        
        number -- ;
        
        NSLog(@"%@ %d",[[NSThread currentThread]name],number);
        
          //休眠1秒
        sleep(1);
        
        if (number == 0) {
            break ;
        }
        
        [lk unlock] ;
    }
    
}