操作系统实验二

操作一：在C#中用Mutex类实现线程的互斥

1.创建新C#项目，并将代码“Mutex_C#示例原代码.txt”复制到源文件中。

2.编写一个程序段（在“// Place code to access non-reentrant resources here.”下），

用于完成从0—30的递增并显示。

3.分别观察启用与不启用互斥体输出结果的差异。

4.采用互斥体的结果：

图一：线程互斥

图二：线程交叉

图三：杀死线程

进程被杀死之后：

线程同步：

此次试验所用的代码：

// This example shows how a Mutex is used to synchronize access // to a protected resource. Unlike Monitor, Mutex can be used with // WaitHandle.WaitAll and WaitAny, and can be passed across

// AppDomain boundaries.

using System;

using System.Threading;

class Test

{

// Create a new Mutex. The creating thread does not own the

// Mutex.

private static Mutex mut = new Mutex();

private const int numIterations = 1;

private const int numThreads = 3;

static void Main()

{

// Create the threads that will use the protected resource.

for (int i = 0; i < numThreads; i++)

{

Thread myThread = new Thread(new ThreadStart(MyThreadProc));

= String.Format("Thread{0}", i + 1);

myThread.Start();

}

Console.Read();

// The main thread exits, but the application continues to

// run until all foreground threads have exited.

}

private static void MyThreadProc()

{

for (int i = 0; i < numIterations; i++)

{

UseResource();

}

}

// This method represents a resource that must be synchronized

// so that only one thread at a time can enter.

private static void UseResource()

{

// Wait until it is safe to enter.

//mut.WaitOne();

Console.WriteLine("{0} has entered the protected area",

);

// Place code to access non-reentrant resources here.

// Simulate some work.

////int num = 0;

////while(true){

//// ++num;

//// if (num > 30) {

//// break;

//// }

//// Console.Write(num + " ");

//// Thread.Sleep(500);

////}

int num = 67;

char c;

while (true)

{

++num;

if(num>100){

break;

}

c = (char)num;

Console.Write(c + " ");

Thread.Sleep(300);

}

Console.Write("\n");

Console.WriteLine("{0} is leaving the protected area\r\n", );

// Release the Mutex.

//注释之后会产生进程交互

//mut.ReleaseMutex();

}

}