如何锁定功能？ [关闭]

问题描述：

var mutex sync.Mutex
func main() {
     handle()
    go register()
}

func register(){
   myObject.OnEvent().DoFunc(HandleConnect)
}
func HandleConnect(){
    handle()
}
func handle() bool {

    mutex = sync.Mutex{}
    mutex.Lock()
    defer mutex.Unlock()
    ....some logic.... do login...
    return true
}

I have a HandleConnect that is called many times in my application I want to lock the handle because if there are many calls I want that only one will do the logic of the login When I run it I got an error fatal error: sync: unlock of unlocked mutex

How I can solve it ?

  var Mutex sync.Mutex 
func main（）{
 handle（）
 go register（  ）
} 
 
func register（）{
 myObject.OnEvent（）。DoFunc（HandleConnect）
} 
func HandleConnect（）{
 handle（）
} 
func handle（）bool {
  
互斥锁= sync.Mutex {} 
互斥锁.Lock（）
延迟互斥锁.Unlock（）
 ....一些逻辑......登录... 
返回true 
} 
   code>  pre> 
 
 我有一个在我的应用程序中被多次调用的HandleConnect 
我想锁定该句柄，因为如果有很多调用，我希望只有一个能做到 登录名
当我运行它时，我遇到错误
 致命错误：同步：解锁的互斥锁解锁 strong>  p> 
 
 
如何解决？ p>  
  div>

答

You have a race condition in your code. You're using a global variable (which is fine, as far as it goes), but then you're constantly resetting the mutex variable:

func handle() bool {
    mutex = sync.Mutex{} // Here you are re-initializing the mutex every time
    mutex.Lock()
    defer mutex.Unlock()
    ....some logic.... do login...
    return true
}

Instead, simply don't reset the variable:

func handle() bool {
    mutex.Lock()
    defer mutex.Unlock()
    ....some logic.... do login...
    return true
}

To visualize the problem, imagine you have a single goroutine going through these steps:

Reset the mutex. mutex = sync.Mutex{}
Lock the mutex. mutex.Lock()
Do stuff ...some logic....
Release the lock. defer mutex.Unlock()

All is fine.

But now imagine you have two groutines, A and B simultaneously running:

A resets the mutex: mutex = sync.Mutex{}
A locks the mutex: mutex.Lock()
A Do stuff
B resets the mutex: mutex = sync.Mutex{} NOTE: The mutex is now unlocked for all goroutines, because it's a global variable!!
A Unlock mutex, and crash, because it's already unlocked

如何锁定功能？ [关闭]

相关推荐