rsmpi_iovec_t
rsmpi_iovec_t iovec_arr[RSM_MAX_IOVLEN];
rsmpi_iovec_t *iovec;
rsmpi_iovec_t *iovec_start = NULL;
size = sg_io.io_request_count * sizeof (rsmpi_iovec_t);
rsmpi_iovec_t *iovec; /* ptr to array */