clarification requested

Linda Stanberry (linda@k2.llnl.gov)
Mon, 14 Apr 1997 11:42:25 -0700 (PDT)

For the query_fn for generalized requests, the spec states that the
status provided to this function is the one provided to MPI in the
call to MPI_{WAIT|TEST}{...} or MPI_GET_STATUS. Should the latter
be MPI_GET_ELEMENTS? While I can clearly see the role that the
query_fn plays for harvesting the status of a GR via MPI_WAIT or
MPI_TEST, I am perplexed as to how the query_fn should be used after this
status is harvested. That is, I think of the query_fn being associated
with the request object and not a status object. Can someone explain
the motivation for this?

Also, I am wondering about the statement that the query_fn can be called
several times for the same request; if the request in nonpersistent, isn't
the request freed after MPI_WAIT or a successful MPI_TEST, implying that
the query_fn could be called only once?

Thanks,

Linda