preg_match正则匹配的字符串

$str ='<a href="http://www.a.com/2010/11-15/5.html">4</a>
  <a href="http://www.b.com/2010/11-15/6.html">5</a>
  <a href="http://www.b.com/2010/11-15/1.html">6</a>
  ';

$ymd=date("y")."/".date("m-d");
$b = preg_match_all('/<a href="(.*?)com/'.$ymd.'(.*?)html">(.*?)</a>/',$a,$c,preg_set_order);

ini_set(‘pcre.backtrack_limit’, 999999999);

ini_set(‘pcre.recursion_limit’, 99999);

ini_set(‘memory_limit’, ’64M’);