t_rcvudata(3xti)														  t_rcvudata(3xti)

Name
       t_rcvudata - receive a data unit

Syntax
       #include <xti.h>

       int t_rcvudata(fd, unitdata, flags)
       int fd;
       struct t_unitdata *unitdata;
       int *flags:

Arguments
       fd	 Identifies the local transport endpoint through which data is received.

       unitdata  Holds	information  associated with the received data unit. The unitdata argument points to a t_unitdata structure containing the
		 following members:
		 struct netbuf addr;
		 struct netbuf opt;
		 struct netbuf udata

		 On return from this call, the members have the following meanings:

		 addr	     Specifies the protocol address of the sending unit.

		 opt	     Identifies protocol-specific options that were associated with this data unit.

		 udata	     Specifies the user data that was received.

		 flags	     Set on return to indicate that the complete data unit was not received.

Description
       This function is used in connectionless mode to receive a data unit from another transport user.

       By default, operates in synchronous mode waits for a data unit to arrive if none is currently available. However, if O_NONBLOCK is  set	by
       means of or udata executes in asynchronous mode and fails if no data units are available.

       The maxlen field of addr, opt, and udata must be set before issuing this function to indicate the maximum size of the buffer for each.

       If the buffer defined in the udata field of unitdata is not large enough to hold the current data unit, the buffer fills and T_MORE sets in
       flags on return to indicate that another should be issued to retrieve the rest of the data unit.  Subsequent  calls  return  zero  for  the
       length of the address and options until the full data unit has been received.

       --------------------------------------------------
       Parameters		Before Call   After Call
       --------------------------------------------------
       fd			x	      /
       unitdata->addr.maxlen	x	      /
       unitdata->addr.len	/	      x
       unitdata->addr.buf	x	      (x)
       unitdata->opt.maxlen	x	      /
       unitdata->opt.len	/	      x
       unitdata->opt.buf	x	      (x)
       unitdata->udata.maxlen	x	      /
       unitdata->udata.len	/	      x
       unitdata->udata.buf	x	      (x)
       flags			/	      x
       --------------------------------------------------

Return Values
       Upon successful completion, a value of 0 is returned. On failure,  a value of -1 is returned, and t_errno is set to indicate the error.

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

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

       [TOUTSTATE]	   The function was issued in the wrong sequence on the transport endpoint referenced by fd.

       [TNODATA]	   O_NONBLOCK was set, but no data units are currently available from the transport provider.

       [TBUFOVFLW]	   The	number of bytes allocated for the incoming protocol address or options is not sufficient to store the information.
			   The unit data information to be returned in unitdata is discarded.

       [TLOOK]		   An asynchronous event has occurred on the transport endpoint and requires immediate attention.

       [TNOTSUPPORT]	   This function is not supported by the underlying transport provider.

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

See Also
       fcntl(2), t_alloc(3xti), t_open(3xti), t_rcvuderr(3xti), t_sndudata(3xti)

																  t_rcvudata(3xti)