Networking Services Library Functions            trcvuderr(3NSL)



NAME
     trcvuderr - receive a unit data error indication

SYNOPSIS
     #include 



     int trcvuderr(int fd, struct tuderr *uderr);


DESCRIPTION
     This routine is part of the  XTI  interfaces  which  evolved
     from the TLI interfaces. XTI represents the future evolution
     of these interfaces. However, TLI interfaces  are  supported
     for  compatibility.  When  using  a TLI routine that has the
     same name as an XTI routine, the  tiuser.h header file  must
     be  used.   Refer  to  the   TLI COMPATIBILITY section for a
     description of differences between the two interfaces.


     This function is  used  in  connectionless-mode  to  receive
     information  concerning  an  error on a previously sent data
     unit, and should only be issued following a unit data  error
     indication.  It  informs the transport user that a data unit
     with a specific destination  address  and  protocol  options
     produced  an  error.  The  argument  fd identifies the local
     transport endpoint through which the error  report  will  be
     received, and uderr points to a tuderr structure containing
     the following members:

       struct netbuf addr;
       struct netbuf opt;
       tscalart error;



     The maxlen field of addr and opt must be set before  calling
     this function to indicate the maximum size of the buffer for
     each. If this field is set to zero for   addr  or   opt,  no
     information is returned in the  buf field of this parameter.


     On return from this call, the addr structure  specifies  the
     destination protocol address of the erroneous data unit, the
     opt structure identifies options that were  associated  with
     the  data  unit,  and  error  specifies a protocol-dependent
     error code.


     If the user does not care to identify  the  data  unit  that
     produced  an  error, uderr may be set to a null pointer, and



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Networking Services Library Functions            trcvuderr(3NSL)



     trcvuderr() will simply clear the error indication  without
     reporting any information to the user.

RETURN VALUES
     Upon successful completion, a value of  0 is returned.  Oth-
     erwise,  a  value  of   -1 is returned and terrno is set to
     indicate an error.

VALID STATES
     TIDLE.

ERORS
     On failure, terrno is set to one of the following:

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


     TBUFOVFLW      The number of bytes allocated for the  incom-
                    ing  protocol  address or options (maxlen) is
                    greater than 0 but not  sufficient  to  store
                    the information. The unit data error informa-
                    tion to be returned in  uderr  will  be  dis-
                    carded.


     TNOTSUPORT    This function is not supported by the  under-
                    lying transport provider.


     TNOUDER       No  unit  data  error  indication   currently
                    exists on the specified transport endpoint.


     TOUTSTATE      The communications endpoint referenced by  fd
                    is  not  in one of the states in which a call
                    to this function is valid.


     TPROTO         This error  indicates  that  a  communication
                    problem has been detected between XTI and the
                    transport provider  for  which  there  is  no
                    other suitable XTI error (terrno).


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


TLI COMPATIBILITY
     The XTI and TLI interface definitions have common names  but
     use   different  header  files.  This,  and  other  semantic



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Networking Services Library Functions            trcvuderr(3NSL)



     differences between the two interfaces are described in  the
     subsections below.

  Interface Header
     The XTI interfaces use the header file,  xti.h.  TLI  inter-
     faces  should  not  use  this  header.   They should use the
     header:
       #include 

  Error Description Values
     The terrno values TPROTO and TOUTSTATE can be  set  by  the
     XTI interface but not by the TLI interface.


     A terrno value that this routine can return under different
     circumstances  than its XTI counterpart is TBUFOVFLW. It can
     be returned even when the maxlen field of the  corresponding
     buffer has been set to zero.

  Option Buffers
     The format of the options in an opt buffer  is  dictated  by
     the  transport  provider.  Unlike the XTI interface, the TLI
     interface does not fix the buffer format.

ATRIBUTES
     See attributes(5)  for descriptions of the following  attri-
     butes:



     
           ATRIBUTE TYPE               ATRIBUTE VALUE       
    
     MT Level                     Safe                        
    


SEE ALSO
     trcvudata(3NSL), tsndudata(3NSL), attributes(5)
















SunOS 5.11           Last change: 7 May 1998                    3