As we saw earlier in the section on mutexes, there are some issues to keep in mind when using mutexes. Naturally these also apply when using locks and other mechanisms based on mutexes, even if some of these issues are smoothed over by these APIs.
One of the things one may get confused about when first using multithreading APIs is what the actual difference is between the different synchronization types. As we covered earlier in this chapter, mutexes underlie virtually all synchronization mechanisms, merely differing in the way that they use mutexes to implement the provided functionality.
The important thing here is that they are not distinct synchronization mechanisms, but merely specializations of the basic mutex type. Whether one would use a regular mutex, a read/write lock, a semaphore - or even something as esoteric as a reentrant (recursive) mutex or lock - depends fully on the particular problem which one is trying to solve.
For the scheduler, we first encountered...