Function gr_test_approx_dot 

pub unsafe extern "C" fn gr_test_approx_dot(
    R: *mut gr_ctx_struct,
    R_ref: *mut gr_ctx_struct,
    maxlen: slong,
    rel_tol: gr_srcptr,
    state: *mut flint_rand_struct,
    test_flags: c_int,
) -> c_int