s2n_negotiate: might need more info in 'more'. (non-blocking mode).

[samrushing]

A non-blocking caller of s2n_negotiate has no way to know whether the socket needs to read or write.
Currently, I think any caller has no choice but to spin calls to s2n_negotiate (though it might reasonably assume that it needs to block on read).

If the value of 'more' was an enum, with WANT_READ or WANT_WRITE, the surrounding event-driven engine will know which event to wait for.

[colmmacc]

That makes sense. It should be very easy to change to something like:

enum {S2N_NOT_BLOCKED, S2N_BLOCKED_ON_READ, S2N_BLOCKED_ON_WRITE }

it raises the question though, should we change the name of the "more" parameter to "blocked" to be more indicative of what it's for?

[samrushing]

BTW Colm, I got my non-blocking sample code working with this. Thanks!
https://github.com/samrushing/coroplusplus/blob/master/coro_s2n.h

[colmmacc]

Nice!