t_sndudata(S)             (TLI/XTI) 6 January 1993             t_sndudata(S)


 Name

    t_sndudata - send a data unit

 Syntax


    TLI syntax


    cc . . .  -lnsls


    #include <sys/tiuser.h>

    int t_sndudata (fd, unitdata)
    int fd;
    struct t_unitdata *unitdata;


    XTI syntax


    cc . . .  -lxti


    #include <xti.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 is sent, and unitdata points to a tunitdata structure
    containing the following members:

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

    netbuf is described in netbut(FP).  In unitdata, addr specifies the pro-
    tocol 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 is passed to the trans-
    port provider; tsndudata does not send zero-length data units.

    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 ONONBLOCK
    is set (via topen or fcntl), tsndudata executes in asynchronous mode
    and fails 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 by topen or
    tgetinfo, the provider generates an EPROTO protocol error.  (See TSYSERR
    below.)

 Return value

    The tsndudata function returns 0 on successful completion and -1 on
    failure, and terrno is set to indicate the error.

 Diagnostics

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

    [TBADDATA]        (XTI only.)  Bad data was detected.

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

    [TFLOW]           ONONBLOCK was set, but the flow control mechanism
                      prevented the transport provider from accepting data at
                      this time.

    [TLOOK]           (XTI only.) A datagram error occurred on this transport
                      endpoint.

    [TNOTSUPPORT]     The use of the TCLTS service type is not supported by
                      the underlying transport provider.

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

    [TSYSERR]         A system error occurred during execution of this func-
                      tion.  One possibility is a protocol error and is indi-
                      cated by EPROTO being set in errno.  Another possibil-
                      ity is an I/O error and is indicated by EIO being set
                      in errno.

 See also

    netbuf(FP), trcvudata(S), trcvuderr(S)

 Standards conformance

    tsndudata is conformant with:
    AT&T SVID Issue 2;
    X/Open Portability Guide, Issue 3, 1989;
    and Intel386 Binary Compatibility Specification, Edition 2 (iBCSe2).