Direct Access Transport Library Functions
                                         datevdmodifycno(3DAT)



NAME
     datevdmodifycno - change the associated CNO for the Event
     Dispatcher

SYNOPSIS
     cc [ flag... ] file... -ldat [ library... ]
     #include 

     DATRETURN
         datevdmodifycno (
         IN    DATEVDHANDLE    evdhandle,
         IN    DATCNOHANDLE    cnohandle
         )


PARAMETERS
     evdhandle    Handle  for   an   instance   of   the   Event
                   Dispatcher.


     cnohandle    Handle for a CNO. The value of DATNULHANDLE
                   specifies no CNO.


DESCRIPTION
     The datevdmodifycno() function changes the associated CNO
     for the Event Dispatcher.


     A Consumer can specify  the  value  of  DATHANDLENUL  for
     cnohandle  to  associate  not CNO with the Event Dispatcher
     instance.


     Upon completion of the datevdmodifycno()  operation,  the
     passed  IN  new  CNO  is  used  for notification. During the
     operation, an event arrival can be delivered to the  old  or
     new  CNO.  If  Notification  is  generated  by  EVD,  it  is
     delivered to the new or old CNO.


     If the EVD is enabled at the  time  datevdmodifycno()  is
     called, the Consumer must be prepared to collect a notifica-
     tion event on the EVD's old CNO as  well  as  the  new  one.
     Checking  immediately  prior to calling datevdmodifycno()
     is not adequate. A notification could  have  been  generated
     after  the  prior  check  and  before  the completion of the
     change.






SunOS 5.11          Last change: 16 Jul 2004                    1






Direct Access Transport Library Functions
                                         datevdmodifycno(3DAT)



     The Consumer can avoid  the  risk  of  missed  notifications
     either  by temporarily disabling the EVD, or by checking the
     prior CNO after invoking this operation.  The  Consumer  can
     disable EVD before a datevdmodifycno() call and enable it
     afterwards. This ensures that any notifications from the EVD
     are delivered to the new CNO only.


     If this function is used to disassociate a CNO from the EVD,
     events  arriving on this EVD might cause waiters on that CNO
     to awaken after  returning  from  this  routine  because  of
     unblocking  a  CNO  waiter already "in progress" at the time
     this routine is called. If this  is  the  case,  the  events
     causing  that  unblocking are present on the EVD upon return
     from the datevdmodifycno() call and can  be  dequeued  at
     that time

RETURN VALUES
     DATSUCES           The operation was successful.


     DATINVALIDHANDLE    Invalid DAT handle.


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



     
           ATRIBUTE TYPE               ATRIBUTE VALUE       
    
     Interface Stability          Standard: uDAPL, 1.1, 1.2   
    
     MT-Level                     Unsafe                      
    


SEE ALSO
     libdat(3LIB), attributes(5)













SunOS 5.11          Last change: 16 Jul 2004                    2






Direct Access Transport Library Functions
                                         datevdmodifycno(3DAT)






















































SunOS 5.11          Last change: 16 Jul 2004                    3