Re: [PATCH] selftests: timers: use 'llabs()' over 'abs()'

[Shuah Khan]

On 11/5/21 2:44 PM, Nick Desaulniers wrote:
> On Fri, Nov 5, 2021 at 9:34 AM Anders Roxell <anders.roxell@xxxxxxxxxx> wrote:
> > When building selftests/timers with clang, the compiler warn about the
> > function abs() see below:
> >
> > posix_timers.c:69:6: warning: absolute value function 'abs' given an argument of type 'long long' but has parameter of type 'int' which may cause truncation of value [-Wabsolute-value]
> >          if (abs(diff - DELAY * USECS_PER_SEC) > USECS_PER_SEC / 2) {
> >              ^
> > posix_timers.c:69:6: note: use function 'llabs' instead
> >          if (abs(diff - DELAY * USECS_PER_SEC) > USECS_PER_SEC / 2) {
> >              ^~~
> >              llabs
> >
> > The note indicates what to do, Rework to use the function 'llabs()'.
> >
> > Signed-off-by: Anders Roxell <anders.roxell@xxxxxxxxxx>
>
> Thanks for the patch!
> Reviewed-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
>
> I wonder why tools/testing/selftests/timers/adjtick.c redefines llabs
> when it already includes stdlib.h, and how that doesn't result in some
> kind of compiler diagnostic.

Hmm. The define in /usr/include/stdlib.h is under #ifdef __USE_ISOC99
Maybe be that explains the reason for the definitions in the other two
timers file?

Anders, I would like to understand this before I take this patch. I see
you sent several patches to other tests as well. Would be useful at
least understand why these defines exist.

thanks,
-- Shuah