# File lib/sqlite3/driver/dl/driver.rb, line 113
    def busy_handler( db, data=nil, &block )
      @busy_handler = block

      unless @busy_handler_callback
        @busy_handler_callback = ::DL.callback( "IPI" ) do |cookie, timeout|
          @busy_handler.call( cookie, timeout ) || 0
        end
      end

      API.sqlite3_busy_handler( db, block&&@busy_handler_callback, data )
    end