Conference azur::mcc

4708.0. "questions on the event collector and example code" by OSAP02::MERMEL () Wed Mar 17 1993 15:15

    I am modifying the event collector code in the examples to support a
    program calling a function to send a message to the evc, and have
    noticed that the  MCC_EVC_API_DNA.c module assigns a channel with  a
    mailbox, then reads the mailbox, but does nothing with the information. 
    Looking at the DECnet manual it talks that the mailbox can provide
    added information abount network operations.  I am curious as to the
    intent of reading from the mailbox, but never looking at the data read.
    
    Also, we would like to keep the network link up at all times, instead
    or reconnecting.  But when we attempt to send another message, we get
    a SYSTEM-F-LINKABORT, which I am guessing means that the mcc_evc_sink
    only accepts one message, than shuts the link down.
    
    One other question is what is happening with the event time, that the
    code determines, then in mcc_evc_write_rpt, is says is "out for now" 
    (the e9s_evc_def.h does not even declare an event_time type).
    
    As we are coding our API to be as efficient as possible, is there
    documentation of the event collector outside the examples.  The buffer
    sent commented in mcc_evc_write_rpt is fairly clear,
    but it just seems that knowing
    more about the evc may help us.
                                      
    
    Thanks,
     
     	Adam Mermel                          

    Well, after reading the decnet networking manual, I verified at least
    that the mailbox read should be checking for a confirm.  However, the 
    read is not by descriptor, but in a special message format (page 8-28)
    of network manual.  The code attempts to pass a descriptor into read
    the mailbox message, which (I believe is incorrect).  What bothers me
    more is that we could be overwriting structures since we are passing
    the wrong thing into the mailbox read.
    
    Has anyone else looked through this code and found other problems?
    
    (btw I am running the SSB V1.3
    
    Thanks,
    	Adam Mermel
     

    hi Adam,
    
    The collector is basically using transparent communication.  i believe
    that the mailbox was included for possible shift to non-transparent
    communication.
    
    Yes, you're right - it looks like the argument to receive the mailbox
    message is incorrect, but it shouldn't cause any problems.
    
    At this time, the sink will accept only one message at a time.  i don't
    know the history behind this decision, but it has been brought to our
    attention that being able to maintain the link is desired.
    
    The event_time argument is not yet implemented.  It is set on the sink
    side as the time the event was received.  
    
    Hope this helps.
    
    -s