how recall iir function in filter.h in c code?

hi, everybody

one question is how recall iir function in filter.h in c code? i try to recall it ,but the it seems can't work.

#include <filters.h>
#include "EQ_Iir.h"
#include <math.h>

float pm coeffs[4];
float pm state[4+1];

---

//Caculate the coeffs

//recall iir function

iir (input, output, coeffs, state, 64, i);

can any one provide me one sample for reference?

another question is if the presicion of the iir function in filter.h is same as the iir in Accelerator ot not?they are both work in 40bit mode.

thank you very much.

Ammon