Stefan, sorry for ignoring your earlier reply. I somehow missed the question at the end.

I believe that users of the Python module are *not* expected to make use of the WANT_READ, WANT_WRITE flags. Firstly because the documentation (of Python's ssl module) doesn't say anything about that, and secondly because the code that's necessary to handle these flags is a prime example for complexity that is imposed by the C API that should be hidden to Python users.

That said, could you give a more specific reference to the O'Relly book (and maybe even page or chapter)? At the moment it's a little hard for me to follow the rest of your message. 

Essentially, if I'm trying to write to a non-blocking, Python SSL socket, I would expect that this either succeeds or raises SSL_WANT_WRITE/READ. Not having read the book, it seems to me this is the only information that's useful to a Python caller. In what situation would you need the more exact state that your C example tracks?