[SR-Users] Computing a time difference when handling a stateless SIP request

Chaigneau, Nicolas nicolas.chaigneau at capgemini.com
Fri Sep 25 17:34:30 CEST 2020

> > 
> > --snip 
> > I would like to compute a time difference (with microseconds
> > precision) when handling a stateless SIP request.
> > --snip
> Welcome!
> Take a look at:
> https://www.kamailio.org/wiki/cookbooks/5.4.x/pseudovariables#timeval
> You can get down to the microsecond level.


Looking at src\modules\pv\pv_time.c, it seems TV functions just use "gettimeofday".
I was looking for a time difference based on a monotonically increasing clock (to avoid possible NTP drifting imprecision).

I've looked at the "benchmark" module which seems to do something like that, but I don't think I can use it for what I need...

Anyhow, I have another question. Using the TV I've come up with the following.
This works, except that I don't know how to convert an int to a string padded with zeroes (e.g. 51 => "051").
Is there a transformation that allows to do that?

	$var(start_time) = $TV(Sn); # allows to cache $TV(s) and $TV(u)


	$var(end_time) = $TV(Sn);
	$var(end_s) = $TV(sn);
	$var(end_us) = $TV(un);
	$var(diff_us) = $var(end_us) - $TV(u) + (1000000 * ($var(end_s) - $TV(s)));

	# convert this to ms (integer part) and us (fractional part)
	$var(diff_ms) = $var(diff_us) / 1000;
	$var(diff_us_f) = $var(diff_us) - (1000 * $var(diff_ms));

	$var(diff_ms_us) = $var(diff_ms) + "." + $var(diff_us_f); # need to format on 3 digits... can we do the equivalent of sprintf("%03u") somehow ?

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