互斥锁(同步锁):有效的防止因多线程抢夺资源造成的数据安全问题.因为线程等待,需要消耗大量的CPU资源.
线程同步:指线程在同一条线上执行(按顺序的执行任务)
self.tickets = 1000;
self.th1 = [[NSThread alloc]initWithTarget:self selector:@selector(sellTickets:) object:nil];
self.th1.name = @"小丽";
[self.th1 start];
self.th2 = [[NSThread alloc]initWithTarget:self selector:@selector(sellTickets:) object:nil];
self.th2.name = @"校长";
[self.th2 start];
self.th3 = [[NSThread alloc]initWithTarget:self selector:@selector(sellTickets:) object:nil];
self.th3.name = @"小明";
[self.th3 start];
// Do any additional setup after loading the view, typically from a nib.
}
-(void)sellTickets:(id)obj{
while (self.tickets > 0) {
@synchronized (self) {
if (self.tickets >0) {
NSLog(@"%@ 买了一张票,还剩%ld张",[NSThread currentThread].name, --self.tickets );
}else{
NSLog(@"票卖完了");
}
}
}
}
