The following constants are used in SetThreadPriority to set the base priority level of a thread.
THREAD_PRIORITY_LOWEST
THREAD_PRIORITY_BELOW_NORMAL
THREAD_PRIORITY_NORMAL
THREAD_PRIORITY_ABOVE_NORMAL
THREAD_PRIORITY_HIGHEST
The same values are returned by GetThreadPriority, in addition to the following error value.
THREAD_PRIORITY_ERROR_RETURN