Function ippiRGBToLab_32f_C3R 

pub unsafe extern "C" fn ippiRGBToLab_32f_C3R(
    pSrc: *const Ipp32f,
    srcStep: c_int,
    pDst: *mut Ipp32f,
    dstStep: c_int,
    roiSize: IppiSize,
) -> IppStatus