characters (or all the characters still available,
    if fewer than 8 characters are available in the input).</p>

<p>Notes:</p>

<ul>
<li>as mentioned above, a <code class="code">%s</code> conversion always succeeds, even if there is
      nothing to read in the input: in this case, it simply returns <code class="code"><span class="string">""</span></code>.</li>
</ul>
<ul>
<li>in addition to the relevant digits, <code class="code"><span class="string">'_'</span></code> characters may appear
    inside num