cmd_name($num)

return cmd

pack_req_command($key, $arg)

return request string

pack_res_command($cmd, $arg)

return response string

read_res_packet($sock, $err_ref, $timeout)

return undef on closed socket or malformed packet

read_text_status($sock, $err_ref)

send_req($sock, $reqref)

wait_for_readability($fileno, $timeout)

given a file descriptor number and a timeout,

wait for that descriptor to become readable

return 0 or 1 on if it did or not