Re: [lwip-users] SNTP

[Bernhard 'Gustl' Bauer]

address@hidden schrieb:
> Bernhard 'Gustl' Bauer wrote:
> > 'sys_timeout()' and 'sys_untimeout()' do not exist, because NO_SYS=1.
> > I'm not sure what to do about this. I don't want to change to NO_SYS=0.
> > I think this configuration is not covered by CVS HEAD so far.
> >    
> I don't think I understand you: which configuration is not covered by 
> CVS HEAD? Anyway, without having sys_timeout() for NO_SYS=1, you have to 
> implement timeouts yourself, it's as simple as that. Just create a 
> function 'sntmp_timeout' and call it at the necessary interval. It's 
> what you have to do for other modules, too, isn't it??

'timers.c' was not included in LWIP 1.3.2 - is this correct? I plan to 
add it to my port.

There is sys_now() needed for this. I don't think it must return system 
time. A ms counter would be ok, wouldn't it.

A problem would be wrap around. It would happen after 49 days (I 
remember win95 crashing after this period). Here a code snippet how I 
would do it:

void
sys_check_timeouts(void)
{
  struct sys_timeo *tmptimeout;
  u32_t diff;
  sys_timeout_handler h;
  void *arg;
  int had_one;
  u32_t now;
#if LWIP_DEBUG_TIMERNAMES
  const char *handler_name;
#endif /* LWIP_DEBUG_TIMERNAMES */

  now = sys_now();
  if (next_timeout) {
    /* @todo: wrap around? */
// --------- new code
    if (now < timeouts_last_time)
      diff = ( 0xFFFFFFFF - timeouts_last_time ) + now + 1 ;
    else
// --------- end of new code
    diff = now - timeouts_last_time;