listen(2)                                                     listen(2)

  listen()

  NAME

    listen() - listen for connections on a socket

  SYNOPSIS

    #include 

    int listen (int s, int backlog)

  DESCRIPTION

    To accept connections, a socket is first created with socket(2), a
    willingness to accept incoming connections and a queue limit for incoming
    connections are specified with listen(2), and then the connections are
    accepted with accept(2). The listen(2) call applies only to sockets of
    type SOCK_STREAM or SOCK_SEQPACKET.

    The backlog parameter defines the maximum length the queue of pending
    connections may grow to. If a connection request arrives with the queue
    full the client may receive an error with an indication of [ECONNREFUSED,]
    or, if the underlying protocol supports retransmission, the request may be
    ignored so that retries may succeed.

  RETURN VALUES

    A 0 return value indicates success; -1 indicates an error.

  ERRORS

    The listen(2) call will fail if:

    [EBADF]
        The argument s is not a valid descriptor.

    [ENOTSOCK]
        The argument s is not a socket.

    [EOPNOTSUPP]
        The socket is not of a type that supports the operation listen(2).

  SEE ALSO

    accept(2)

    connect(2)

    socket(2)

  USAGE NOTES

    The listen function is thread safe.

    The listen function is async-signal safe.