NI_GPCT_SUBDEV
s = &dev->subdevices[NI_GPCT_SUBDEV(counter_index)];
s = &dev->subdevices[NI_GPCT_SUBDEV(i)];
dev->subdevices[NI_GPCT_SUBDEV(0)].buf_change = &pcimio_gpct0_change;
dev->subdevices[NI_GPCT_SUBDEV(1)].buf_change = &pcimio_gpct1_change;