sync 库使用小结

sync 主要用于 golang 中的同步控制。虽然 golang 更推荐 chan 这种通过通信来共享资源的方式，但有时候直接使用 sync 的效果更好，它是chan 方式很好的补充。本文简单介绍一下 sync 的使用方式。

##互斥锁

func TestMutex() {
	var mutex sync.Mutex
	sum := 0
	for i := 0; i < 10; i++ {
		go func(t int) {
			mutex.Lock()
			defer mutex.Unlock()
			sum += t
			fmt.Println(t)
		}(i)
	}
	time.Sleep(time.Second)
	fmt.Printf("Sum: %v\n", sum)
}

##条件变量

func TestCond() {
	cond := sync.NewCond(&sync.Mutex{})
	for i := 0; i < 10; i++ {
		go func(t int) {
			time.Sleep(time.Second)
			cond.L.Lock()
			defer cond.L.Unlock()
			cond.Wait()
			fmt.Println(t)
		}(i)
	}

	time.Sleep(2 * time.Second)
	//cond.Signal()
	cond.Broadcast()
}

##读写锁

func TestRWMutex() {
	var rwMutex sync.RWMutex
	sum := 0
	for i := 0; i < 10; i++ {
		go func(t int) {
			rwMutex.RLock()
			//time.Sleep(time.Second)
			defer rwMutex.RUnlock()
			fmt.Printf("Sum: %v\n", sum)
		}(i)
		go func(t int) {
			rwMutex.Lock()
			defer rwMutex.Unlock()
			sum += t
		}(i)
	}
	time.Sleep(5 * time.Second)
}

##Pool

func TestPool() {
	var pool sync.Pool
	pool.New = func() interface{} { return "Hello" }
	for i := 0; i < 10; i++ {
		s := pool.Get()
		fmt.Println(s)
		pool.Put("World" + strconv.FormatInt(int64(i), 10))
	}
}

##Once

func TestOnce() {
	once := &sync.Once{}
	for i := 0; i < 10; i++ {
		go func(t int) {
			once.Do(func() {
				fmt.Println("Hello Once!")
			})
			fmt.Println("Hello World!")
		}(i)
	}
	time.Sleep(time.Second)
}

##WaitGroup

func TestWaitGroup() {
	var wg sync.WaitGroup
	for i := 0; i < 10; i++ {
		wg.Add(1)
		go func(t int) {
			defer wg.Done()
			fmt.Println(t)
		}(i)
	}
	wg.Wait()
}

来源：CSDN

作者：libing_thinking

链接：https://blog.csdn.net/u013148156/article/details/49893309