# File lib_ctrl/rucy/params.rb, line 340
    def subprocess_user=(new_user)
      case (new_user)
      when Numeric
        if (new_user < 0) then
          raise "not allowed negative number of subprocess user: #{new_user.inspect}"
        end
      when String
        # nothing to do.
      else
        raise "not allowed object type of subprocess user: #{new_user.class}"
      end
      @params['subprocess_user'] = new_user
    end