ed while some more
      characters are needed to read the current conversion specification.</li>
</ul>
<ul>
<li>Raise <code class="code"><span class="constructor">Invalid_argument</span></code> if the format string is invalid.</li>
</ul>
<p>Note:</p>

<ul>
<li>as a consequence, scanning a <code class="code">%s</code> conversion never raises exception
    <code class="code"><span class="constructor">End_of_file</span></code>: if the end of input is reached the conversion succeeds and
    simply returns the 