Function fftw_plan_r2r_3d

pub unsafe extern "C" fn fftw_plan_r2r_3d(
    n0: c_int,
    n1: c_int,
    n2: c_int,
    in_: *mut f64,
    out: *mut f64,
    kind0: fftw_r2r_kind,
    kind1: fftw_r2r_kind,
    kind2: fftw_r2r_kind,
    flags: c_uint,
) -> fftw_plan