Should I use static fields and interlocked together?

Question

Should I use static fields and interlocked together, in cases when i need to provide thread safety and atomic operations with static fields, Is static fields are atomic by default? For example:

Interlocked.Increment(ref Factory.DefectivePartsCount);

Thanks.

Answer 1

Yes.

The field (assuming Int32) is atomic, not because it's static but because it's 32 bits.

How ever, Factory.DefectivePartsCount += 1 requires a read and a write action on the variable so the whole operation is not thread-safe.

Answer 2

static doesn't guarantee anything in terms of thread-safety. Hence, an increment will still not be atomic even if the variable is static. As such, you will still need to use classic synchronization mechanisms depending on the situation. In your case Interlocked.Increment is fine.