NSLock简单应用

 1 #import "AppDelegate.h"
 2
 3 @interface AppDelegate ()
 4
 5 @end
 6
 7 @implementation AppDelegate
 8
 9 -(void)dealloc{
10
11     [_window release];
12     [super dealloc];
13 }
14
15
16 - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
17     self.window = [[UIWindow alloc]initWithFrame:[UIScreen mainScreen].bounds];
18     self.window.backgroundColor = [UIColor blackColor];
19
20     [self.window makeKeyAndVisible];
21
22     [_window release];
23
24     //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
25     NSLock *lk = [[NSLock alloc]init];
26
27     NSThread *thread1 = [[NSThread alloc]initWithTarget:self selector:@selector(therad:) object:lk];
28
29     thread1.name = @"1号窗口";
30
31     [thread1 start];
32
33
34
35     NSThread *therad2 = [[NSThread alloc]initWithTarget:self selector:@selector(therad:) object:lk];
36
37     therad2.name = @"2号窗口" ;
38
39 //    therad2.threadPriority = 0.9 ;
40
41     [therad2 start];
42
43
44
45     NSThread *therad3 = [[NSThread alloc]initWithTarget:self selector:@selector(therad:) object:lk];
46
47     therad3.name = @"3号窗口" ;
48
49     therad3.threadPriority = 1 ;
50
51     [therad3 start];
52
53
54
55
56
57
58     return YES;
59 }
60
61
62 //模拟售票
63 -(void)therad:(id)object{
64
65     NSLock *lk = (NSLock *)object ;
66
67     //票数100张
68     static int number = 100 ;
69
70     while (1) {
71
72         // 加线程锁，提高数据访问的安全性
73         [lk lock];
74
75         number -- ;
76
77         NSLog(@"%@ %d",[[NSThread currentThread]name],number);
78
79           //休眠1秒
80         sleep(1);
81
82         if (number == 0) {
83             break ;
84         }
85
86         [lk unlock] ;
87     }
88
89 }