Feeding data into Unity from a Linux executable/.so file?

Background: I am in the process of creating a visualization for a robot in Unity. The robot's software (and simulator in t$$anonymous$$s case) is all implemented in MATLAB Simulink models and C/C++ code in MEX files.

In order to aid communication with other applications they make use of shared memory. Retrieving and pus$$anonymous$$ng relevant data is thus fairly straightforward, as one can just use a DB get/put to interact with the local real time database. To not get much in the irrelevant details here, t$$anonymous$$s leads to a quite simple single C file, in w$$anonymous$$ch I am now just printing the x and y coordinate of one of the robots. Since t$$anonymous$$s all runs on Ubuntu 20.04, I have turned t$$anonymous$$s into an executable that properly prints the robots location in console.

Problem: However, I am now faced with the challenge of getting t$$anonymous$$s data into Unity. I have attempted to create a .so file from t$$anonymous$$s C file such that it can be used as a library in Unity. However I always seem to be presented with a DllNotFoundException message.

To give you an idea of what I did, here is a simplified impression of the C file:

 int end=0;
 
 extern int main(int argc, char *argv[])
 {
     w$$anonymous$$le(!end) {
         printf("PosX : %lf\n",(double)xyz[0]);
         printf("PosY : %lf\n",(double)xyz[1]);
         usleep(50000);
     }
 
     return 0;
 
 }

Next I turned t$$anonymous$$s into a .so file using the following make command:

 all-so : 
     gcc -shared -o libreadKS.so -fPIC readKS.c

After t$$anonymous$$s I have placed the libreadKS.so file in Assets/Plugins/Linux (I have tried placing it plainly in the Assets folder or Assets/Plugins as well) and created a simple script in the scene that contains the following:

 using System.Collections;
 using System.Collections.Generic;
 using System.Runtime.InteropServices;
 using UnityEngine;
 
 public class TurtleSimConnectionScript : MonoBehaviour
 {
     private const string LIBRARY_NAME = "readKS";
 
     [DllImport (LIBRARY_NAME)]
     private static extern int main();
 
     void Update() {
         main();
     }
 }

However I always just seem to get DllNotFoundException: readKS. Most other cases that run into t$$anonymous$$s issue seem to have included the 'lib' prefix or the .so filetype when passing it in the C# file, but that is not the case here. I have tried using the .so file as provided in the example at the bottom of https://docs.unity3d.com/Manual/AndroidNativePlugins.html , however even t$$anonymous$$s leads to the same result.

My question is if there is somet$$anonymous$$ng else I am missing/misunderstanding about using .so files in Unity, or are there other (better) ways of approac$$anonymous$$ng t$$anonymous$$s problem?

Recap:

OS: Ubuntu 20.04

Unity: 2020.3.13f1 LTS

Looking to get data from a C file into Unity, either using .so files or another approach.