[ILUG] [OT] C time_elapsed function

[Padraig Brady]

Liam Bedford wrote:

> On Tue, Nov 06, 2001 at 06:09:50PM +0000, Padraig Brady came forth with:
> 
>>Treanor, Ciaran wrote:
>>
>>
>>>>Note time() and gettimeofday() both return seconds since 1970,
>>>>and hence won't do as the value returned isn't guaranteed to
>>>>monotonically increase (as the system date can change).
>>>>
>>>>
>>>There ain't nothing you can do about that.
>>>
>>>Have you looked at /proc/uptime ? It gives the time in seconds
>>>since the last boot.
>>>
>>>Ciaran T.
>>>
>>I could use this but:
>>1. It wraps after 472 days
>>2. It's linux specific
>>
>>
> steal the code from top or uptime? It seems to work for them across a lot of
> machines (probably with lots of special cases though).
> 
> Use the source Luke <g>
> 
> L.

 From procps:

int uptime(double *uptime_secs, double *idle_secs) {
     double up=0, idle=0;

     FILE_TO_BUF(UPTIME_FILE,uptime_fd);
     if (sscanf(buf, "%lf %lf", &up, &idle) < 2) {
	fprintf(stderr, "bad data in " UPTIME_FILE "\n");
	return 0;
     }
     SET_IF_DESIRED(uptime_secs, up);
     SET_IF_DESIRED(idle_secs, idle);
     return up;	/* assume never be zero seconds in practice */
}

I.E. no use. ah well,

Padraig.