Deep understanding Net (2) kernel mode 2 Kernel mode construct semaphone

In depth understanding of .Net The construction mode of thread synchronization in （ Two ） Kernel mode construction

Preface

Kernel-mode Constructs Generally translated as kernel mode construction ,
Constructs It is both a noun and a verb , But the translation for construction feels a bit like a verb , I think it's better to translate it into a noun , After all s Of , It means multiple , Verbs obviously can't express more than one , Such as kernel mode constructs , Kernel mode constructs .

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Environmental statement
IDE：Visual Studio 2022
OS：Win10
.NET：.Net4.6.1

One 、 What is the semaphore ？

What is the semaphore ？ I remember when the teacher said "yes" 0,1 To control thread blocking and unblocking is a semaphore . This is the most basic understanding of semaphores , Semaphores are atomic and controlled by the system kernel int Variable , by 0 Blocking threads when , Greater than 0 Remove the obstruction when you need to .

Two 、 Code writing

1. Write a Semaphone Lock of

The code is as follows （ Example ）：

  public class SemaphoreTest
    {
    

        public void TestStart() 
        {
    
        
            Console.WriteLine(" SemaphoreTest TestStart Start !");
            IntObj intObj = new IntObj();
      
            for (Int32 i = 0; i < 10; i++)
            {
    
            
                new TaskFactory().StartNew(() =>
                {
    
                    AddCount(intObj);
                    AddCount_SemaphoreLock(intObj);
                });
            }
            Console.WriteLine(" SemaphoreTest TestStart END !");
        }
        
        public void AddCount(IntObj intObj)
        {
      

            intObj.num_Norml++;
            WriteLineThread(intObj);
            Thread.Sleep(500);
        }
        SemaphoreLock tLock = new SemaphoreLock(1);

        public void AddCount_SemaphoreLock(IntObj intObj)
        {
    
            tLock.Enter();

            intObj.num_Lock++;
            WriteLineThread_SemaphoreLock(intObj);
            Thread.Sleep(500);
            tLock.Leave();
            tLock.Leave();
        }
        public void WriteLineThread(IntObj intObj )
        {
    
            Thread.Sleep(200);
            ConsoleColor currentForeColor = Console.ForegroundColor;
            Console.ForegroundColor = ConsoleColor.Red;
            Console.WriteLine($"num_Norml :{
       intObj.num_Norml},{
      Thread.CurrentThread.ManagedThreadId}");
            Console.ForegroundColor = currentForeColor;
            Thread.Sleep(200);
        }

        public void WriteLineThread_SemaphoreLock(IntObj intObj)
        {
    
            Thread.Sleep(200);
            ConsoleColor currentForeColor = Console.ForegroundColor;
            Console.ForegroundColor = ConsoleColor.Green;
            Console.WriteLine($"num_Lock:{
       intObj.num_Lock},{
      Thread.CurrentThread.ManagedThreadId}");
            Console.ForegroundColor = currentForeColor;
            Thread.Sleep(200);
        }

    }     

2. test Semaphone Lock effect

The code is as follows （ Example ）：

       public class SemaphoreTest
    {
    

        public void TestStart() 
        {
    
        
            Console.WriteLine(" SemaphoreTest TestStart Start !");
            IntObj intObj = new IntObj();
      
            for (Int32 i = 0; i < 10; i++)
            {
    
            
                new TaskFactory().StartNew(() =>
                {
    
                    AddCount(intObj);
                    AddCount_EventLock(intObj);
                });
            }
            Console.WriteLine(" SemaphoreTest TestStart END !");
        }
        
        public void AddCount(IntObj intObj)
        {
      

            intObj.num_Norml++;
            WriteLineThread(intObj);
            Thread.Sleep(500);
        }
        SemaphoreLock tLock = new SemaphoreLock(10);  
        public void AddCount_EventLock(IntObj intObj)
        {
    
            tLock.Enter();

            intObj.num_Lock++;
            WriteLineThread_EventLock(intObj);
            Thread.Sleep(500);

            tLock.Leave();
        }
        public void WriteLineThread(IntObj intObj )
        {
    
            Thread.Sleep(200);
            ConsoleColor currentForeColor = Console.ForegroundColor;
            Console.ForegroundColor = ConsoleColor.Red;
            Console.WriteLine($"num_Norml :{
       intObj.num_Norml},{
      Thread.CurrentThread.ManagedThreadId}");
            Console.ForegroundColor = currentForeColor;
            Thread.Sleep(200);
        }

        public void WriteLineThread_EventLock(IntObj intObj)
        {
    
            Thread.Sleep(200);
            ConsoleColor currentForeColor = Console.ForegroundColor;
            Console.ForegroundColor = ConsoleColor.Green;
            Console.WriteLine($"num_Lock:{
       intObj.num_Lock},{
      Thread.CurrentThread.ManagedThreadId}");
            Console.ForegroundColor = currentForeColor;
            Thread.Sleep(200);
        }

    }

The effect is as follows
When the semaphore lock is initialized, the maximum is allowed 10 Thread effects

When the semaphore lock is initialized, the maximum is allowed 1 Thread effects

The result at this point is the same as AutoResetEvent Event lock has the same effect

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summary

It can be seen that , When the maximum number of threads 1 When , Semaphores and AutoResetEvent The effect of the event is the same . However, if the semaphore is released multiple times, it may occur SemaphoreFullException It's abnormal .
When the maximum number of threads is greater than 1 When , It will be possible to have multiple threads simultaneously variable . In that case ？