Hi folks, The standard defines MPI_ERR_UNSUPPORTED_DATAREP as an I/O error class, with the meaning "Unsupported datarep passed to MPI_FILE_SET_VIEW". However, datareps are also passed as input to MPI_PACK_EXTERNAL and MPI_UNPACK_EXTERNAL. Shouldn't these functions use the same error class for unsupported datareps, rather than MPI_ERR_ARG? Can we update the description of MPI_ERR_UNSUPPORTED_DATAREP (page 551, line 10) to also include MPI_PACK_EXTERNAL and MPI_UNPACK_EXTERNAL as a ticket-0 item for MPI 3.1, or will this need to happen in a later version? Thanks, -Fab