int comedi_sv_init (comedi_sv_t * sv, comedi_t * device, unsigned int subdevice, unsigned int channel);
The function comedi_sv_init() initializes the slow varying Comedi structure sv to use the device device, the analog input subdevice subdevice, and the channel channel. The slow varying Comedi structure is used by comedi_sv_measure() to accurately measure an analog input by averaging over many samples. The default number of samples is 100. This function returns 0 on success, -1 on error.