(PECL event >= 1.2.6-beta)
EventDnsBase::setSearchNdots — Set the 'ndots' parameter for searches
$ndots
   ): bool
   Set the
   'ndots'
   parameter for searches. Sets the number of dots which, when found in a
   name, causes the first query to be without any search domain.
  
ndots
    The number of dots.
   成功时返回 true, 或者在失败时返回 false。