Function mp_rat_decimal_len

pub unsafe extern "C" fn mp_rat_decimal_len(
    r: mp_rat,
    radix: mp_size,
    prec: mp_size,
) -> mp_result

Reports the length in bytes of the buffer needed to convert r using the mp_rat_to_decimal() function with the specified radix and prec. The buffer size estimate may slightly exceed the actual required capacity.