What are the differences between semaphores and mutexes?

What are the differences 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 explain how a semaphore works?

Sure! A semaphore maintains a count that represents the number of available resources. When a thread wants to access a resource, it decrements the count. If the count is zero, the thread must wait until another thread releases a resource and increments the count.

What about the use cases for each?

Mutexes are typically used for protecting shared resources, ensuring that only one thread can access them at a time. Semaphores are used when you want to limit the number of threads that can access a resource simultaneously, like controlling access to a pool of connections.

Are there any performance differences between them?

Yes, mutexes can be more efficient for protecting a single resource since they have less overhead. Semaphores, however, can introduce more complexity and overhead due to their counting mechanism, especially when managing multiple threads.