EBADF The socket descriptor is invalid. ECONNRESET A connection was forcibly closed by a peer. EFAULT The message argument is not in a readable or writable part of user address space. EINTR This function was interrupted by a signal before any data was available. EINVAL The MSG_OOB flag is set, and no out-of-band data is available. The value of the msg_iovlen member of the msghdr structure is less than or equal to zero or is greater than IOV_MAX. ENOBUFS The system has insufficient resources to complete the call. ENOMEM The system did not have sufficient memory to fulfill the request. ENOTCONN A receive is attempted on a connection- oriented socket that is not connected. ENOTSOCK The socket descriptor is invalid. EOPNOTSUPP The specified flags are not supported for this socket type. EWOULDBLOCK The socket is marked nonblocking, and no data is ready to be received.