What basic MPI datatype one should use in MPI functions for variables of MPI_Offset type? For example, MPI_Offset offsets[nprocs]; MPI_Allreduce(MPI_IN_PLACE, offsets, nprocs, MPI_???, MPI_MAX, MPI_COMM_WORLD); Will there be a new base type, MPI_OFFSET (all capitals)? Wei-keng