[mpiwg-tools] question about MPI_T_EVENT_SET_DROPPED_HANDLER

[Raffenetti, Kenneth J.]

On 1/25/21, 12:44 PM, "mpiwg-tools on behalf of Raffenetti,	Kenneth J. via mpiwg-tools" <mpiwg-tools-bounces at lists.mpi-forum.org on behalf of mpiwg-tools at lists.mpi-forum.org> wrote:

    On 1/25/21, 11:46 AM, "Marc-André Hermanns" <hermanns at itc.rwth-aachen.de> wrote:
       
        For me (although not explicitly defined in the text) that would imply
        that the dropped callback is only invoked once the library is in a
        state where a callback (and user_data) for the same level is defined
        and could be invoked.
        
        Does this make sense and clarify your concerns? Do you think this need
        more clarification in the text?
        
    I see. Yes, that makes sense for my implementation issue.
    
I may have spoken too soon. I'm looking at pg 763, ln 37 (Handling Dropped Events):

   If an event occurs...[and] no callback function meeting the required callback safety level is registered, the event data may be dropped. To discover such data loss, the user can set a handler function for a specific event-registration handle.

If a callback function meeting the required safety level is not registered, how do I decide which user buffer to provide to the dropped handler?

Ken