On Wed, Apr 23, 2025 at 05:01:41PM +0200, Thomas Weißschuh wrote:
> This is used in various selftests and will be handy when integrating
> those with nolibc.
>
> Signed-off-by: Thomas Weißschuh <thomas.weisssc...@linutronix.de>
> ---
> tools/include/nolibc/time.h | 7 +++++++
> tools/testing/selftests/nolibc/nolibc-test.c | 1 +
> 2 files changed, 8 insertions(+)
>
> diff --git a/tools/include/nolibc/time.h b/tools/include/nolibc/time.h
> index
> 28a1549adb14e2087fa8fbdb7e9c35e1c3f22c2a..760133c574ece97165e3bba5616a387deaf07aff
> 100644
> --- a/tools/include/nolibc/time.h
> +++ b/tools/include/nolibc/time.h
> @@ -105,6 +105,13 @@ int clock_settime(clockid_t clockid, struct timespec *tp)
> }
>
>
> +static __inline__
> +double difftime(time_t time1, time_t time2)
> +{
> + return time1 - time2;
> +}
Thanks for making me discover difftime(). I've never heard about it, and
seeing it return a double looks totally weird, but that's how it is indeed.
In case time_t would be unsigned, this would return a large unsigned
value. I think it could be more robust to explicitly cast the two
inputs to long:
return (long)time1 - (long)time2;
> diff --git a/tools/testing/selftests/nolibc/nolibc-test.c
> b/tools/testing/selftests/nolibc/nolibc-test.c
> index
> aed71de4b4f3dd1f183c7fc25e5a5cee466600ed..fd8bab42e75157967658690005bc9142360fc135
> 100644
> --- a/tools/testing/selftests/nolibc/nolibc-test.c
> +++ b/tools/testing/selftests/nolibc/nolibc-test.c
> @@ -1423,6 +1423,7 @@ int run_stdlib(int min, int max)
> CASE_TEST(toupper_noop); EXPECT_EQ(1, toupper('A'),
> 'A'); break;
> CASE_TEST(abs); EXPECT_EQ(1, abs(-10), 10);
> break;
> CASE_TEST(abs_noop); EXPECT_EQ(1, abs(10), 10);
> break;
> + CASE_TEST(difftime); EXPECT_EQ(1, difftime(200.,
> 100.), 100.); break;
Then here maybe test it in reverse to make sure the types don't cause trouble:
CASE_TEST(difftime); EXPECT_EQ(1, difftime(100.,
200.), -100.); break;
Willy
