Re: [gpsd-dev] Bug found in unix_to_iso8601()

[Gary E. Miller]

Yo Peter!

On Thu, 08 Nov 2018 21:43:38 +0000 (GMT)
Peter Liu <address@hidden> wrote:

> I found this bug but I will not be able to submit patches any time
> soon.

Bug reports are good. 

> Could someone please take a quick look at the following in gpsutil.c?
> There should be a trivial fix.
> 
>     (void)snprintf(fractstr, sizeof(fractstr), "%.3f", fractional);
> 
> 
> If the fractional part is 0.9995 or larger, it is rounded up and
> tractstr returns "1.000". It is not ".999".

I thought snprintf("%f") truncated, not rounded up.

> The end result is that with fixtime=1541766896.999512,
> unix_to_iso8601() produces "2018-11-09T12:34:56.000Z" instead of
> "2018-11-09T12:34:57.000Z". We lost one whole second.

You have seen this?  If so, can you provide that as a test case?

I'll add a test case for this right now.

RGDS
GARY
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Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
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