f="#options"><i>options</i></a> <b>")"</b> <i>extended-regexp</i>
     |   <b>"(?"</b> <a href="#options"><i>options</i></a> <b>":"</b> <i>extended-regexp</i> <b>")"</b>
</pre>
</td></tr>
</table>
<p>
An atom is either an ERE enclosed in parenthesis, a bracket
expression, a <tt>.</tt> (period), an assertion, or a literal.
</p>

<p>
The dot (<tt>.</tt>) matches any single character.
If the <code>REG_NEWLINE</code> compilation flag (see <a
href="api.html">API manual</a>) is specified, the newline
character is