T_SNDUDATA(3N)                       SysV                       T_SNDUDATA(3N)



NAME
     t_sndudata - send a data unit

SYNOPSIS
     #include <tiuser.h>

     int t_sndudata(fd, unitdata)
     int fd;
     struct t_unitdata *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 specifies the
     protocol address of the destination user, opt identifies protocol-
     specific options that the user wants associated 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, no data unit will be passed to the
     transport provider; t_sndudata will not send zero-length data units.

     By default, t_sndudata 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 is
     set (via t_open or fcntl), t_sndudata will execute in asynchronous mode
     and will fail under such conditions.

     If t_sndudata is issued from an invalid state, or if the amount of data
     specified in udata exceeds the TSDU size as returned by t_open or
     t_getinfo, the provider will generate an EPROTO protocol error.  (See
     TSYSERR below.)

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

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

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

     [TFLOW]           O_NDELAY was set, but the flow control mechanism
                       prevented the transport 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 execution of this
                       function.

SEE ALSO
     intro(3), t_rcvudata(3N), t_rcvuderr(3N)
     Programming with the SysV Transport Interface