mutex 互斥量

有用参考：http://blog.csdn.net/yl2isoft/article/details/46003467

摘抄记录：
using System.Threading;

class Example
{
// 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 newThread = new Thread(new ThreadStart(ThreadProc));
newThread.Name = String.Format("Thread{0}", i + 1);
newThread.Start();
}

// The main thread exits, but the application continues to
// run until all foreground threads have exited.
}

private static void ThreadProc()
{
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, and do not enter if the request times out.
Console.WriteLine("{0} is requesting the mutex", Thread.CurrentThread.Name);
if (mut.WaitOne(1000)) {
Console.WriteLine("{0} has entered the protected area",
Thread.CurrentThread.Name);

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

// Simulate some work.
Thread.Sleep(5000);

Console.WriteLine("{0} is leaving the protected area",
Thread.CurrentThread.Name);

// Release the Mutex.
mut.ReleaseMutex();
Console.WriteLine("{0} has released the mutex",
Thread.CurrentThread.Name);
}
else {
Console.WriteLine("{0} will not acquire the mutex",
Thread.CurrentThread.Name);
}
}
}