We're waiting after the connect() is issued for a certain delay (2 seconds in this case). During the delay, a connect signal can occur, or the wait can time out. At the end of the timeout, the code checks the exception mask to see if an exception occurred, or if the socket indicates write status.

Last night I discovered that EINPROGRESS on Linux will always eventually mean that the socket becomes writable -- an exception will never be set. You then have to check getsockopt(sock, SOL_SOCKET, SO_ERROR, &buf, &size) to see if a failed connection error was set. Really strange.