c - pthreads mutex vs semaphore

Question

What is the difference between semaphores and mutex provided by pthread library ?

Answer 1

semaphores have a synchronized counter and mutex's are just binary (true / false).

A semaphore is often used as a definitive mechanism for answering how many elements of a resource are in use -- e.g., an object that represents n worker threads might use a semaphore to count how many worker threads are available.

Truth is you can represent a semaphore by an INT that is synchronized by a mutex.