C caller function block does not work right with unsigned integer variables

Hello,

I've been trying to implement a simple C-code into simulink, which bitshfits 2 integers and then puts them into a variable.

The code worked fine with on my visual studio compiler but here on simulink it always outputs a 0 no matter how I change the input. My first guess is that Simulink might not like the data types I'm using in my C model

The model, aswell as the C-code and the header file are in the same directory, ofcourse.

Here I created the same function but with malab code. It worked pretty well but I would have liked to know how I should go on about making the C code work.

Are there any alternatives to fix my problem?

I appreciate every hint.