What is the difference between using a semaphore and a mutex for thread synchronization?

Mutex (mutual exclusion) is a synchronization primitive that provides exclusive access to a resource: only one thread can own the mutex at a time.

Semaphore is a more general primitive that allows limiting the number of threads that can access a resource simultaneously. The semaphore's value is a count of permits.

Main differences:

• Mutex is a semaphore with a maximum value of 1.
• Mutex provides mutual exclusion, semaphore limits parallelism.

Example:

• Mutex is used to protect a critical section so that only one thread executes it.
• Semaphore can be used to limit the number of threads working with a connection pool (for example, a maximum of 5).

Thus, mutex is a special case of semaphore with a single permit.