[mpiwg-tools] question about MPI_T_EVENT_SET_DROPPED_HANDLER

Raffenetti, Kenneth J. raffenet at mcs.anl.gov
Fri Jan 22 13:56:06 CST 2021


I am working on implementing MPI_T events in MPICH and came across a potential issue. MPI_T_EVENT_SET_DROPPED_HANDLER does not take a user_data argument, but the callback signature and standard text suggest that it should be there.

  The argument user_data is the pointer to user-allocated memory that was passed to the MPI implementation during callback registration.

Am I correct in understanding that user_data is specified for each callback registration? I.e. if a user registers callbacks for different safety levels, those callbacks can be associated with different user_data buffers. If so, it seems the dropped handler registration is missing this functionality.


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