What is the difference between semaphores and mutexes?

What is the difference between semaphores and mutexes?

Semaphores and mutexes are both synchronization primitives used in concurrent programming, but they serve different purposes. A mutex is a lock that allows only one thread to access a resource at a time, while a semaphore can allow multiple threads to access a resource, up to a specified limit.

Can you give me an example of when to use a semaphore?

Sure! You would use a semaphore when you want to limit the number of threads that can access a particular resource, like a pool of database connections. For instance, if you have 5 connections available, you can use a semaphore initialized to 5 to control access.

What about mutexes? When should I use them?

You should use a mutex when you need to ensure that only one thread can access a critical section of code or a shared resource at a time. This prevents race conditions and ensures data integrity.

Are there any performance differences between using semaphores and mutexes?

Yes, there can be performance differences. Mutexes are generally faster for locking and unlocking since they are simpler, while semaphores can introduce more overhead due to their counting mechanism and the need to manage multiple threads.