t_sync(3)                                                     t_sync(3)

  t_sync()

  NAME

    t_sync - synchronise transport library

  SYNOPSIS

    #include 

    int t_sync(
        int fd)

  DESCRIPTION

    The t_sync(3) function has only one parameter.

    Parameters     Before call     After call

    fd             x               /

    For the transport endpoint specified by fd, t_sync(3) synchronises the
    data structures managed by the transport library with information from the
    underlying transport provider. In doing so, it can convert an
    uninitialised file descriptor (obtained using open(2), dup(2) or as a
    result of a fork(2) and exec(2) ) to an initialised transport endpoint,
    assuming that the file descriptor referenced a transport endpoint, by
    updating and allocating the necessary library data structures. This
    function also allows two cooperating processes to synchronise their
    interaction with a transport provider.

    For example, if a process forks a new process and issues an exec(2), the
    new process must issue a t_sync(3) to build the private library data
    structure associated with a transport endpoint and to synchronise the data
    structure with the relevant provider information.

    It is important to remember that the transport provider treats all users
    of a transport endpoint as a single user. If multiple processes are using
    the same endpoint, they should coordinate their activities so as not to
    violate the state of the transport endpoint. The function t_sync(3)
    returns the current state of the transport endpoint to the user, thereby
    enabling the user to verify the state before taking further action. This
    coordination is only valid among cooperating processes; it is possible
    that a process or an incoming event could change the endpoint's state
    after a t_sync(3) is issued.

    If the transport endpoint is undergoing a state transition when t_sync(3)
    is called, the function will fail.

  VALID STATES

    ALL - apart from T_UNINIT

  ERRORS

    On failure, t_errno is set to one of the following:

    [TBADF]
        The specified file descriptor does not refer to a transport endpoint.
        This error may be returned when the fd has been previously closed or
        an erroneous number may have been passed to the call.

    [TPROTO]
        This error indicates that a communication problem has been detected
        between XTI and the transport provider for which there is no other
        suitable XTI error (t_errno).

    [TSTATECHNG]
        The transport endpoint is undergoing a state change.

    [TSYSERR]
        A system error has occurred during execution of this function.

  RETURN VALUE

    On successful completion, the state of the transport endpoint is returned.
    Otherwise, a value of -1 is returned and t_errno is set to indicate an
    error. The state returned is one of the following:

    T_UNBND
        Unbound.

    T_IDLE
        Idle.

    T_OUTCON
        Outgoing connection pending.

    T_INCON
        Incoming connection pending.

    T_DATAXFER
        Data transfer.

    T_OUTREL
        Outgoing orderly release (waiting for an orderly release indication).

    T_INREL
        Incoming orderly release (waiting for an orderly release request).

  SEE ALSO

    dup(2)

    exec(2)

    fork(2)

    open(2)

  USAGE NOTES

    The t_sync function is not thread safe.

    The t_sync function is not async-signal safe.