condition holds when the scan begins.</li>
<li><code class="code"><span class="constructor">S</span></code>: reads a delimited string argument (delimiters and special
      escaped characters follow the lexical conventions of OCaml).</li>
<li><code class="code">c</code>: reads a single character. To test the current input character
      without reading it, specify a null field width, i.e. use
      specification <code class="code">%0c</code>. Raise <code class="code"><span class="constructor">Invalid_argum