comedi_sv_measure man page
comedi_sv_measure — slowly-varying inputs
int comedi_sv_measure (comedi_sv_t * sv, double * data);
The function comedi_sv_measure() uses the slowly varying Comedi structure sv to measure a slowly varying signal. If sucessful, the result (in physical units) is stored in the location pointed to by data, and the number of samples is returned. On error, -1 is returned.