t_look(3)t_look(3)NAMEt_look() - look at the current event on a transport endpoint
The function returns the current event on the transport endpoint speci‐
fied by fd. This function enables a transport provider to notify a
transport user of an asynchronous event when the user is calling func‐
tions in synchronous mode. Certain events require immediate notifica‐
tion of the user and are indicated by a specific error, [TLOOK], on the
current or next function to be executed.
This function also enables a transport user to poll a transport end‐
point periodically for asynchronous events.
All - apart from
XTI Internet Protocol-specific Information
As soon as a segment with the TCP urgent pointer set enters the TCP
receive buffer, the event is indicated. remains set until all data up
to the byte pointed to by the TCP urgent pointer has been received. If
the urgent pointer is updated, and the user has not yet received the
byte previously pointed to by the urgent pointer, the update is trans‐
parent to the user.
is not fork-safe.
Upon success, returns a value that indicates which of the following
allowable events has occurred, or returns zero if no event exists. One
of the following events is returned:
T_LISTEN connection indication received.
T_CONNECT connect confirmation received.
T_DATA normal data received.
T_ERROR (TLI ONLY) fatal error occurred.
T_EXDATA expedited data received.
T_DISCONNECT disconnect received.
T_UDERR datagram error indication.
T_ORDREL orderly release indication.
T_GODATA (XTI only) flow control restrictions on normal data
flow have been lifted. Normal data may be sent
T_GOEXDATA (XTI only) flow control restrictions on expedited
data flow have been lifted. Expedited data may be
On failure, is set to one of the following:
[TBADF] The specified identifier does not refer to a transport
[TSYSERR] A system error has occurred during execution of this
[TPROTO] (XTI only) This error indicates that a communication
problem has been detected between XTI and the trans‐
port provider for which there is no suitable XTI (
SEE ALSOt_open(3), t_snd(3), t_sndudata(3), thread_safety(5).