EBADF              The socket descriptor is invalid.
    ECONNABORTED       A connection has been aborted.
    EFAULT             The addr argument is not in a writable part of
                       the user address space.
    EINTR              The accept() function was interrupted by a
                       signal before a valid connection arrived.
    EINVAL             The socket is not accepting connections.
    EMFILE             There are too many open file descriptors.
    ENFILE             The maximum number of file descriptors in the
                       system is already open.
    ENETDOWN           TCP/IP Services was not started.
    ENOBUFS            The system has insufficient resources to
                       complete the call.
    ENOMEM             The system was unable to allocate kernel
                       memory.
    ENOTSOCK           The socket descriptor is invalid.
    EOPNOTSUPP         The reference socket is not of type SOCK_
                       STREAM.
    EPROTO             A protocol error occurred.
    EWOULDBLOCK        The socket is marked nonblocking, and no
                       connections are present to be accepted.