高手帮我看下这个代码,请帮忙注释下,谢谢!
<!-- Code highlighting produced by Actipro CodeHighlighter (freeware) http://www.CodeHighlighter.com/ --> //获取记录的总笔数 public function num_rows($results) { //$results参数是select_query($sql)的返回结果 if(!is_bool($results)) { //**********这个地方看不懂,为什么用is_bool()取反判断,这样有什么用? $num = mysql_num_rows($results); $this->write_log("获取的记录条数为".$num); return $num; } else { return 0; } }