What is the difference between Semaphore and SemaphoreSlim in C#?

What is the difference between Semaphore and SemaphoreSlim in C#?

Semaphore is a synchronization primitive that allows a limited number of threads to access a resource, while SemaphoreSlim is a lightweight alternative that is more efficient for scenarios where the wait time is expected to be short.

When should I use Semaphore instead of SemaphoreSlim?

You should use Semaphore when you need to manage access to a resource across multiple processes, as it can work across process boundaries. SemaphoreSlim is best for scenarios within a single process.

Can you give an example of using SemaphoreSlim?

Sure! Here's a simple example: you can create a SemaphoreSlim instance with a count of 2, allowing two threads to enter the critical section at the same time. Use WaitAsync() to wait for access and Release() to signal that a thread is done.

Are there any performance differences between the two?

Yes, SemaphoreSlim is generally faster than Semaphore because it avoids the overhead of kernel transitions, making it more suitable for scenarios with short wait times.