How unique is ManagedThreadID?

For ManagedThreadID, MSDN says:

Gets a unique i开发者_如何学JAVAdentifier for the current managed thread.

In what context does "unique" apply?

Is this unique per process?

Per application domain?

Per machine?

Per .NET runtime? (if I have both MS.NET and Mono running)

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Thread ID is unique per process during a thread's lifecycle. After the thread terminates, its number can be reused.

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Since threads from the ThreadPool also have to honour this property, and there is one ThreadPool per process (as stated in this MSDN article), I would think that the ManagedThreadId is most likely unique per process.