strange bug in gettimeofday function

Lev Bishop lev.bishop@gmail.com
Mon Feb 12 00:50:00 GMT 2007


On 2/11/07, Christopher Faylor wrote:
> On Sun, Feb 11, 2007 at 07:20:14PM +0300, Andrew Makhorin wrote:
> >Hi,
> >
> >I detected a strange bug in the standard function gettimeofday.
> >It *sometimes* reports the time which being expressed as the integer
> >number of milliseconds is *less* than the time obtained *earlier* with
> >the same function.
> >
> >The expression 1000000 * tv.tv_sec + tv.tv_usec is calculated in
> >64-bit arithmetic, so overflow cannot happen. The negative difference
> >in the time values on two successive calls is about 100 milliseconds.
> >
> >cygcheck.out is attached.
>
> In cases like this a simple test case is really required.  If this is
> really true then calling gettimeofday in a loop should be enough to
> demonstrate the problem.

I have a hunch that it will be a good idea to have a look at what the
result of GetSystemTimeAdjustment() is on the machine exhibiting this
behaviour, at the time it exhibits this behaviour.

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