t_rcvudata(3N)                 DG/UX 5.4R3.00                 t_rcvudata(3N)


NAME
       trcvudata - receive a data unit

SYNOPSIS
       #include <tiuser.h>

       int trcvudata (int fd, struct tunitdata *unitdata, int *flags);

DESCRIPTION
       This function is used in connectionless mode to receive a data unit
       from another transport user.  fd identifies the local transport
       endpoint through which data will be received, unitdata holds
       information associated with the received data unit, and flags is set
       on return to indicate that the complete data unit was not received.
       unitdata points to a tunitdata structure containing the following
       members:

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

       The maxlen [see netbuf in intro(3)] field of addr, opt, and udata
       must be set before issuing this function to indicate the maximum size
       of the buffer for each.

       On return from this call, addr specifies the protocol address of the
       sending user, opt identifies protocol-specific options that were
       associated with this data unit, and udata specifies the user data
       that was received.

       By default, trcvudata operates in synchronous mode and will wait for
       a data unit to arrive if none is currently available.  However, if
       ONDELAY or ONONBLOCK is set (via topen or fcntl), trcvudata will
       execute in asynchronous mode and will fail if no data units are
       available.

       If the buffer defined in the udata field of unitdata is not large
       enough to hold the current data unit, the buffer will be filled and
       TMORE will be set in flags on return to indicate that another
       trcvudata should be issued to retrieve the rest of the data unit.
       Subsequent trcvudata call(s) will return zero for the length of the
       address and options until the full data unit has been received.

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

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

       [TNODATA]           ONDELAY or ONONBLOCK 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



Licensed material--property of copyright holder(s)                         1

t_rcvudata(3N)                 DG/UX 5.4R3.00                 t_rcvudata(3N)


                           store the information.  The unit data information
                           to be returned in unitdata will be discarded.

       [TLOOK]             An asynchronous event has occurred on this
                           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
       intro(3), trcvuderr(3N), tsndudata(3N).
       UNIX System V Network Programmer's Guide.

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





































Licensed material--property of copyright holder(s)                         2