Threads share memory, and there's only one stack, so I would say the answer to your question is yes. I think you might run into problems with the static variable, but not the member variable. Threads all share the same program stack, but they keep track of what variables on the stack are theirs. So if you have 10 threads of the same function that all create a local variable 'x', there will be 10 'x' variables on the stack.

But as I said, I only think you'll run into problems with a static variable. It's very possible that you might not.