TSNDUDATA(3N-SVR4) RISC/os Reference Manual  TSNDUDATA(3N-SVR4)



NAME
     t_sndudata - send a data unit

SYNOPSIS
     #include <tiuser.h>

     int tsndudata (int fd, struct tunitdata *unitdata);

DESCRIPTION
     This function is used in connectionless mode to send a data
     unit to another transport user.  fd identifies the local
     transport endpoint through which data will be sent, and
     unitdata points to a t_unitdata structure containing the
     following members:

          struct netbuf addr;
          struct netbuf opt;
          struct netbuf udata;

     netbuf is described in intro(3).  In unitdata, addr speci-
     fies the protocol address of the destination user, opt iden-
     tifies protocol-specific options that the user wants associ-
     ated with this request, and udata specifies the user data to
     be sent.  The user may choose not to specify what protocol
     options are associated with the transfer by setting the len
     field of opt to zero.  In this case, the provider may use
     default options.

     If the len field of udata is zero, and the sending of zero
     bytes is not supported by the underlying transport provider,
     tsndudata will return -1 with t_errno set to TBADDATA.

     By default, tsndudata operates in synchronous mode and may
     wait if flow control restrictions prevent the data from
     being accepted by the local transport provider at the time
     the call is made.  However, if O_NDELAY or O_NONBLOCK is set
     (via t_open or fcntl), tsndudata will execute in asynchro-
     nous mode and will fail under such conditions.

     If tsndudata is issued from an invalid state, or if the
     amount of data specified in udata exceeds the TSDU size as
     returned in the tsdu field of the info argument of t_open or
     t_getinfo, the provider will generate an EPROTO protocol
     error.  (See TSYSERR below.)  If the state is invalid, this
     error may not occur until a subsequent reference is made to
     the transport endpoint.

     On failure, t_errno may be set to one of the following:

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




                        Printed 11/19/92                   Page 1

TSNDUDATA(3N-SVR4) RISC/os Reference Manual  TSNDUDATA(3N-SVR4)



     [TFLOW]           O_NDELAY or O_NONBLOCK was set, but the
                       flow control mechanism prevented the tran-
                       sport provider from accepting data at this
                       time.

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

     [TSYSERR]         A system error has occurred during execu-
                       tion of this function.

     [TBADDATA]        nbytes is zero and sending zero bytes is
                       not supported by the transport provider.

SEE ALSO
     intro(3), t_rcvudata(3N), t_rcvuderr(3N).

DIAGNOSTICS
     tsndudata returns 0 on successful completion and -1 on
     failure t_errno is set to indicate the error.



































 Page 2                 Printed 11/19/92