 most are used at some arbitrarily-fixed precision, say
      100 decimal digits, like <a href="../../../../../libs/multiprecision/doc/html/index.html" target="_top">Boost.Multiprecision</a>
      <code class="computeroutput"><span class="identifier">cpp_dec_float_100</span></code>.
    </p>
<p>
      <a href="../../../../../libs/multiprecision/doc/html/index.html" target="_top">Boost.Multiprecision</a>
      can operate in both ways, but the most popular choice is likely to be about
      a hundred decimal