"It's actually a file-level static."
Hmm, does that even work, I wonder... I always thought it had to be associated with a particular (user) thread, typically as an automatic variable (on the stack). How does this interact with any (other) dynamic initialisation? But I defer to the TBB team for this one.
"myThreadCount is 8 and it's there for legacy reasons."
Explicit uses of thread counts have often been counterproductive.