#include <comedilib.h>
comedi_range * comedi_get_range (comedi_t * device, unsigned int subdevice, unsigned int channel, unsigned int range);
The function comedi_get_range() returns a pointer to a comedi_range structure that contains information that can be used to convert sample values to or from physical units. The pointer is valid until the Comedi device device is closed. If there is an error, NULL is returned.