EADDRINUSE         Configuration problem. There are insufficient
                       ports available for the attempted connection.
                       The inet subsystem attribute ipport_
                       userreserved should be increased.
    EADDRNOTAVAIL      The specified address is not available from
                       the local machine.
    EAFNOSUPPORT       The addresses in the specified address family
                       cannot be used with this socket.
    EALREADY           A connection request is already in progress
                       for the specified socket.
    EBADF              The socket descriptor is invalid.
    ECONNREFUSED       The attempt to connect was rejected.
    EFAULT             The name argument is not a valid part of the
                       user address space.
    EHOSTUNREACH       The specified host is not reachable.
    EINPROGRESS        O_NONBLOCK is set for the file descriptor
                       for the socket, and the connection cannot be
                       immediately established; the connection will
                       be established asynchronously.
    EINTR              The connect() function was interrupted by a
                       signal while waiting for the connection to be
                       established. Once established, the connection
                       may continue asynchronously.
    EINVAL             The value of the namelen argument is invalid
                       for the specified address family, or the sa_
                       family member in the socket address structure
                       is invalid for the protocol.
    EISCONN            The socket is already connected.
    ELOOP              Too many symbolic links were encountered in
                       translating the file specification in the
                       address.
    ENETDOWN           The local network connection is not
                       operational.
    ENETUNREACH        No route to the network or host is present.
    ENOBUFS            The system has insufficient resources to
                       complete the call.
    ENOTSOCK           The socket descriptor is invalid.
    EOPNOTSUPP         The socket is listening and cannot be
                       connected.
    EPROTOTYPE         The specified address has a different type
                       than the socket bound to the specified peer
                       address.
    ETIMEDOUT          The connection request timed out without
                       establishing a connection.
    EWOULDBLOCK        The socket is nonblocking, and the connection
                       cannot be completed immediately. It is
                       possible to use the select() function to
                       select the socket for writing.