t_look(3)						     Library Functions Manual							 t_look(3)

NAME

       t_look() - look at the current event on a transport endpoint

SYNOPSIS

DESCRIPTION

       The  function  returns the current event on the transport endpoint specified by fd.  This function enables a transport provider to notify a
       transport user of an asynchronous event when the user is calling functions 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 endpoint periodically for asynchronous events.

   Valid States
       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 transparent to the user.

   Fork Safety
       is not fork-safe.

RETURN VALUE

       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 again.

       T_GOEXDATA	  (XTI only) flow control restrictions on expedited data flow have been lifted.  Expedited data may be sent again.

ERRORS

       On failure, is set to one of the following:

       [TBADF]		The specified identifier does not refer to a transport endpoint.

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

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

SEE ALSO

       t_open(3), t_snd(3), t_sndudata(3), thread_safety(5).

STANDARDS CONFORMANCE

																	 t_look(3)