Do semaphores prevent instruction reordering?

Question

I was looking for an awaitable equivalent of lock statements in C#. Some people suggest using a binary SemaphoreSlim in the following way:

await         


        

Answer 1

SemaphoreSlim, and pretty much all of the other synchronization constructs, are built using a Monitor (or other types that are built on top of a Monitor) internally, which is exactly how a lock is implemented, giving you the same guarantees.