t_sndudata(3N)

NAME
     t_sndudata - send a data unit

SYNOPSIS
     #ifdef _XOPEN_SOURCE
     #include <xti.h>
     #else
     #include <tiuser.h>
     #endif

     int t_sndudata (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(3N).  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, and the sending of zero bytes is not
     supported by the underlying transport provider, t_sndudata will return -1
     with t_errno set to TBADDATA.

     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 or
     O_NONBLOCK 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 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.

     This function resides within both the X/Open compliant libxnet and the
     SVR4 compliant libnsl Network Services libraries.  Network Services
     applications which require X/Open compliance must link-load with -lxnet.
     Network Services applications which require SVR4 compliance must link-
     load with -lnsl.
     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 or O_NONBLOCK 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.

     TOUTSTATE         If _XOPEN_SOURCE is defined and t_sndudata() is issued
                       in the wrong sequence on the transport endpoint
                       referenced by fd, the TOUTSTATE error value is returned
                       within the variable t_errno.

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

     TBADDATA          There are multiple conditions which could cause this
                       t_errno to be generated.  One condition is:  nbytes is
                       zero and sending zero bytes is not supported by the
                       transport provider.  Another condition is: if
                       _XOPEN_SOURCE is defined and a single send was
                       attempted specifying a TSDU greater than that specified
                       by the current values of the TSDU field in the info
                       argument.

SEE ALSO
     intro(3N), fcntl(2), t_alloc(3N), t_open(3N), t_rcvudata(3N),
     t_rcvuderr(3N)

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