[foreign-jextract] Different behavior between C and Java program

[Thomas Stüfe]

>From looking at your debug output, I guess it's a locale issue. The '.' is
not recognized as a decimal point, so unit[0]='.' and unit[1]='0'.

Cheers, Thomas

On Sat, Feb 27, 2021 at 11:57 AM Filip Krakowski <krakowski at hhu.de> wrote:

> Hi,
>
> I stumbled upon a weird behavior I haven't seen before. I use jextract
> to generate bindings for ucx (https://github.com/openucx/ucx) and
> implement an object oriented wrapper for it. While running some examples
> on our machines, I noticed that ucx doesn't seem to detect our
> InfiniBand hardware when called from Java. On the other hand, a C
> program using the same functions in the same order is working as
> expected. I opened an issue at the ucx repository showing the source
> files, my setup and what I did to get these results
> (https://github.com/openucx/ucx/issues/6406).
>
> I pinpointed this issue to a call to sscanf which doesn't parse the
> input correctly when called from Java
> (https://github.com/openucx/ucx/issues/6406#issuecomment-787050535).
> Since I am not entirely sure that this is caused by ucx, I would like to
> ask if anyone did experience something similar in the past and knows how
> to troubleshoot this problem. I can't really think of a reason why the
> code suddenly behaves differently when called from Java.
>
> Best regards
> Filip
>