I don't have anything useful to add I'm afraid. I posted mainly to point out that the extended error is to be expected (and accommodated) with non-blocking handles; and that the logic of your test code shouldn't require non-blocking socket.
With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'
Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
"Science is about questioning the status quo. Questioning authority".
In the absence of evidence, opinion is indistinguishable from prejudice.
In reply to Re^3: Error - A non-blocking socket operation could not be completed immediately.