What are the differences between a lock and a semaphore?

What are the differences between a lock and a semaphore?

Locks and semaphores are both synchronization primitives used in concurrent programming, but they serve different purposes. A lock 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 lock?

Sure! You would use a lock when you need to protect a critical section of code that modifies shared data, ensuring that only one thread can execute that section at a time.

And when would I use a semaphore instead?

You would use a semaphore when you want to limit the number of threads that can access a particular resource simultaneously, such as a connection pool where you want to allow a maximum of 5 concurrent connections.

Are there any performance differences between them?

Yes, locks can lead to contention and performance bottlenecks if many threads are trying to acquire the same lock. Semaphores can be more efficient in scenarios where you want to allow multiple threads to proceed, reducing contention.