Hands-On Parallel Programming with C# 8 and .NET Core 3

Lock, mutex, and semaphore

Lock and mutex are locking constructs that allow only one thread to access a protected resource. Lock is a shortcut implementation that uses another higher-level synchronization class called Monitor.

Semaphore is a locking construct that allows a specified number of threads to access a protected resource. Lock can only synchronize access inside a process, but if we need to access a system-level resource or shared memory, we need to actually synchronize access across multiple processes. A mutex allows us to synchronize access to resources across processes by providing a kernel-level lock.

The following table provides a comparison of the capabilities of these constructs:

As we can see, Lock and Mutex only allow single-thread ...