That bug was caused by the TLS slots pointer being uninitialized in the newly created Boost fiber, not a change in Windows API. TLS pre-dates boost::context, th

That bug was caused by the TLS slots pointer being uninitialized in the newly created Boost fiber, not a change in Windows API. TLS pre-dates boost::context, the field had existed since the very first commit. I already said "MS would rather you not", obviously, otherwise they would have documented the TIB. The fact remains that tons of production systems rely on officially-unofficial elements of NT's architecture and this is one such element that is heavily relied on by everyone who uses boost stackful coroutines. Hyrum's Law in action.