The third argument to GetQueuedCompletionStatus is a pointer to a uintptr, not a uint32. Users of this functions have therefore been corrupting their memory every time they used it. Either that memory corruption was silent (dangerous), or their programs didn't work so they chose a different API to use.

I intend to submit CLs fixing the function signature. This could perturb compatibility. But either nobody used these functions because they were broken or there's a lingering security issue, so I think it may be justified.

CC @bradfitz @alexbrainman @FiloSottile