acted (and
corresponding bits appended) until any of the following occurs:<br />

<ul>
<li> <tt>n</tt> bits are stored into the bitset;</li>
<li> end-of-file, or an error, occurs on the input sequence;</li>
<li> the next available input character isn't a bitset digit</li>
</ul>
<br /> If no exception caused the function to exit then <tt>is.width(0)</tt> is
     called, regardless of how many characters were actually extracted. The
     sentry object k is destroyed.
<br />
<br />If the function extracts no c