Advanced Python Programming

Locks do not lock anything

An additional aspect of locks is the fact that they do not actually lock anything. The only way that a lock object is utilized, with respect to a specific shared resource, is for the threads and processes interacting with that resource to also interact with the lock. In other words, if those threads and processes choose to not check with the lock before accessing and altering the shared resource, the lock object itself cannot stop them from doing so.

In our examples, you have seen that, to implement the acquiring/releasing process of a lock object, the instructions of a thread or process will be wrapped around by a lock context manager; this specification is dependent on the implementation of the thread/process ...