[uClibc] clock() for long-running process

[Joakim Tjernlund]

> > 
> > I see, but using CPU time for measuring elapsed time is not very accurate, is it?
> 
> We're talking about usage of clock() like
> 
>   start = clock();
>   < do some work >
>   elapsed = clock() - start;
> 
> where the programmer _is_ attempting to measure cpu time.

ohh, sorry. My bad.

> 
> > I can only find two way to measure elapsed time in Linux, the return
> > value from times()(needs scaling) or gettimeofday(). gettimeofday() has
> > the disadvantage that it may change time between polls.
> 
> If you're trying to measure elapsed wall clock time on linux and you need
> only second accuracy, you can use the difference in system uptime.
> 
>   #include <sys/sysinfo.h>
> 
>   /* Return system uptime in seconds. */
> 
>   long uptime(void)
>   {
>     struct sysinfo info;
> 
>     sysinfo(&info);
> 
>     return info.uptime;
>   }

OK, thanks. Hmm, why is info.uptime a long instead of an unsigned long? What happens when
info.uptime reaches negative values? I would guess that uptime just keeps counting until
it wraps to 0?

 Jocke