Hi everyone,
this is my first post on this forum! I'm a Modelica newbie, so please forgive me if I hit a very simple issue.
Basically, I tried to compile a simple DLL using mingw64 on my Windows 10 machine, then I created this very basic model:

model test_dll

  function my_sum

      input Real a;

      input Real b;

      output Real result;

    external "C" annotation(Library="libtest_om");

  end my_sum;

  

  Real result;

  parameter Real a = 1;

  parameter Real b = 2;

equation 

  result = my_sum(a, b);

end test_dll;

It calls the my_sum external function from the libtest_om.dll library. The content of the library is just the function my_sum:

double my_sum(double a, double b)

{

    double res;

    res = a + b;

    return res;

}

And the DLL itself is located in the path <workdir>/Resources/Library folder.
When I launch the simulation like this, it builds ok, but it fails at startup:


Now, after several failed attempts, I tried to follow the examples of the Modelica Guide, and I tried to put my dll in the <workdir> path. I modified the model as follows:

model test_dll

  function my_sum

      input Real a;

      input Real b;

      output Real result;

    external "C" annotation(Library="libtest_om", LibraryDirectory="modelica://test_dll");

  end my_sum;

  

  Real result;

  parameter Real a = 1;

  parameter Real b = 2;

equation 

  result = my_sum(a, b);

end test_dll;

and now it works fine!


So, the question is: do you know if there is something that I'm missing when trying to link my external function in a directory that is different from the working directory?

Thank you