# File lib/daemons/pidfile.rb, line 34
    def self.find_files(dir, progname, delete = false, pid_delimiter = nil)
      files = Dir[File.join(dir, "#{progname}#{pid_delimiter || DEFAULT_PID_DELIMITER}*.pid")]
      files = Dir[File.join(dir, "#{progname}.pid")] if files.size == 0

      files.delete_if { |f| not (File.file?(f) and File.readable?(f)) }
      if delete
        files.delete_if do |f|
          pid = File.open(f) { |h| h.read }.to_i
          rsl =  !Pid.running?(pid)
          if rsl
            begin; File.unlink(f); rescue ::Exception; end
            yield(pid, f) if block_given?
          end
          rsl
        end
      end

      files
    end