OSSpinLock与os_unfair_lock

OSSpinLock

已经被Apple废弃，因为线程安全问题，就不说了。想了解的可以百度搜OSSpinLock安全问题。

os_unfair_lock

API说明

1、OS_UNFAIR_LOCK_INIT ，初始化锁

2、os_unfair_lock_lock ，获得锁

3、os_unfair_lock_unlock ，解锁

下面是自己的理解和例子代码

#import <Foundation/Foundation.h>
@interface NSLockTest : NSObject
- (void)forTest;
@end

#import "NSLockTest.h"
#import <os/lock.h>
@interface NSLockTest()
@end
@implementation NSLockTest
os_unfair_lock theLock ;
- (void)forTest
{
    // 创建信号量
    theLock = OS_UNFAIR_LOCK_INIT;
    NSThread *thread1 = [[NSThread alloc]initWithTarget:self selector:@selector(download1) object:nil];
    [thread1 start];
    NSThread *thread2 = [[NSThread alloc]initWithTarget:self selector:@selector(download2) object:nil];
    [thread2 start];
}
-(void)download1
{
    os_unfair_lock_lock(&theLock);
    NSLog(@"第一个线程同步操作开始");
    sleep(8);
    NSLog(@"第一个线程同步操作结束");
    os_unfair_lock_unlock(&theLock);
}
-(void)download2
{
    os_unfair_lock_lock(&theLock);
    NSLog(@"第二个线程同步操作开始");
    sleep(1);
    NSLog(@"第二个线程同步操作结束");
    os_unfair_lock_unlock(&theLock);
}
@end

注意

os_unfair_lock，apple文档中空空如也。

1、申明，os_unfair_lock theLock ;

2、初始化，theLock = OS_UNFAIR_LOCK_INIT;

3、加锁，os_unfair_lock_lock(&theLock);

4、解锁，os_unfair_lock_unlock(&theLock);

5、思路和其他互斥锁类似。