Using the SemaphoreSlim construct

This recipe will show how to SemaphoreSlim is a lightweight version of Semaphore; it limits the number of threads that can access a resource concurrently.

Getting ready

To step through this recipe, you will need Visual Studio 2012. There are no other prerequisites. The source code for this recipe could be found at BookSamples\Chapter2\Recipe3.

How to do it...

To understand limiting a multithreaded access to a resource with the help of the SemaphoreSlim construct, perform the following steps:

1. Start Visual Studio 2012. Create a new C# Console Application project.

2. In the Program.cs file add the following using directives:

   using System;
   using System.Threading;

3. Below the Main method, add the following code snippet:

   static SemaphoreSlim _semaphore = new SemaphoreSlim(4);

   static void AccessDatabase(string name, int seconds)
   {
     Console.WriteLine("{0} waits to access a database", name);
     _semaphore.Wait();
     Console.WriteLine("{0} was granted an access to a database",name...