C#: Do I need to lock a static class when accessing from separate threads?

Question

I have a static class with a few methods that just take in a byte array, parses it, and returns a structure. I need to call these methods from many separate threads. Do I need a lock() or some kind of thread-safety within the methods? I can't get my head around it.

Answer 1

If your method is reentrant you don't need any locks.

In general, you need locks whenever multiple threads access a shared resource. When the method just calculates something from its arguments without accessing any shared resource, there is nothing to lock.

Answer 2

Yes, the lock prevents multiple threads accessing the same data at the same time, which would lead to inconsistent / unpredictable behaviour usually.

Answer 3

If your methods have shared resource then you need synchronize access to it. It your case there is no shared resource and therefore no need to lock anything.