Function gmp_mpfr_sys::mpfr::mpfr_can_round

pub unsafe extern fn mpfr_can_round(b: *const __mpfr_struct,
                                    err: mpfr_exp_t,
                                    rnd1: mpfr_rnd_t,
                                    rnd2: mpfr_rnd_t,
                                    prec: mpfr_prec_t)
                                    -> c_int