In the description of MPI_COMM_FREE we presently give the following advise to implementors.

A reference-count mechanism may be used: the reference count is
incremented by each call to \func{MPI\_COMM\_DUP}, and decremented by
each call to \func{MPI\_COMM\_FREE}. The object is ultimately
deallocated when the count reaches zero.

I do not think it can ever be valid to implement MPI_COMM_DUP by simply returning a new handle for an existing communicator object while bumping its reference count because the output communicator must have a different context than the original. Assuming I have not missed something, it seems this advise is nonsense.

Is removing this the kind of change that should go on the MPI 2.2 list? I will be surprised if anyone offers a rationale for keeping the advise but I am also not quite comfortable that it fits within the "clean up" rules for MPI 2.1 at this late stage.

Thoughts?

Dick



Dick Treumann - MPI Team/TCEM
IBM Systems & Technology Group
Dept 0lva / MS P963 -- 2455 South Road -- Poughkeepsie, NY 12601
Tele (845) 433-7846 Fax (845) 433-8363