... comedi_data_write -- write single sample to channel . ... int comedi_data_write (comedi_t * device, unsigned int subdevice, unsigned int channel, unsigned int range, unsigned int aref, lsampl_t data); . Writes a single sample on the channel that is specified by the Comedi device device, the subdevice subdevice, and the channel channel. If appropriate, the device is configured to use range specification range and analog reference type aref. ... On sucess, comedi_data_write() returns 0. ...