DECnet Out-of-band data

DECnet supports the sending and receiving of out-of-band data via the MSG_OOB flag for recv and send. If a send with the MSG_OOB flag is sent, the recv must be posted with MSG_OOB in order to read the data. To check for the presence of out-of-band data, use select with exceptfds set, or a WSAAsyncSelect with FD_OOB set.

DECnet does not support inline out-of-band data via the setsockopt SO_OOBINLINE flag.