What are the differences between condition variables and semaphores?

What are the differences between condition variables and semaphores?

Condition variables and semaphores are both synchronization primitives used in concurrent programming, but they serve different purposes. Condition variables are used for signaling between threads, allowing one thread to wait for a condition to be true before continuing. Semaphores, on the other hand, are used to control access to a shared resource by maintaining a count of available resources.

Can you give an example of when to use each?

Sure! Use a condition variable when you have a thread that needs to wait for a specific condition, like a producer waiting for a buffer to have space. Use a semaphore when you want to limit the number of threads accessing a resource, like a pool of database connections.

Are there any performance differences between them?

Yes, condition variables can be more efficient for signaling between threads, as they avoid busy-waiting. Semaphores can introduce overhead due to their counting mechanism, especially if the count is frequently updated.

Which one is easier to implement?

Condition variables are generally easier to implement for simple signaling scenarios, while semaphores can be more complex due to their counting logic. It depends on the specific use case.