IODC_IO_READ
if ((ret = (*ctiodc)(ctdev.pz_hpa, IODC_IO_READ, ctdev.pz_spa,
IODC_IO_READ, pzdev->pz_spa, pzdev->pz_layers,
IODC_IO_READ, pzdev->pz_spa, pzdev->pz_layers,
(rw == F_READ? IODC_IO_READ: IODC_IO_WRITE),