How do I use SemaphoreSlim in C#?

How do I use SemaphoreSlim in C#?

SemaphoreSlim is a lightweight semaphore that can be used to control access to a resource in a concurrent environment. You can create an instance of SemaphoreSlim by specifying the initial count and the maximum count.

Can you show me a code example?

Sure! Here's a simple example:

using System;
using System.Threading;

class Program
{
    static SemaphoreSlim semaphore = new SemaphoreSlim(2); // Allow 2 concurrent threads

    static void Main()
    {
        for (int i = 0; i < 5; i++)
        {
            Thread thread = new Thread(AccessResource);
            thread.Start(i);
        }
    }

    static void AccessResource(object id)
    {
        Console.WriteLine($"Thread {id} is waiting to access the resource.");
        semaphore.Wait(); // Wait to enter
        try
        {
            Console.WriteLine($"Thread {id} has entered the resource.");
            Thread.Sleep(2000); // Simulate work
        }
        finally
        {
            Console.WriteLine($"Thread {id} is leaving the resource.");
            semaphore.Release(); // Release the semaphore
        }
    }
}

What happens if I don't release the semaphore?

If you don't release the semaphore, other threads will be blocked and unable to enter the critical section, which can lead to a deadlock situation if all threads are waiting indefinitely.