Hello everyone and thank you by advance for your further help,

I would like to call an external function, coded in C, to calculate the Eigen values of a Matrix of complexes.
The C-function is stored in a directory, "Eigen_Library", constituted as follows:

Eigen_Library:
       -> Eigen_Library_Header.h
       -> Eigen_Library.lib
       -> Eigen_Files:
              -> Eigen_Library_c_File.c
              -> Eigen_Library_cpp_File.cpp      (the C++ function is actually encapsulated into a C function)

The header file contains the following:

#ifndef EXAMPLE_H_INCLUDED
#define EXAMPLE_H_INCLUDED
typedef unsigned int size_t;
extern void fct_tab_c(double *, double *, size_t, size_t);
#ifdef __cplusplus
     extern "C" {
#endif
         void fct_tab(double *,double *, size_t, size_t);
#ifdef __cplusplus
     }
#endif


#endif //
EXAMPLE_H_INCLUDED


To call the function defined in the header file, I define a package, "PersoEigenLibrary", as follows:

encapsulated package PersoEigenLibrary
  import Modelica.ComplexMath.*;
  import Complex;
  import EigenLibrary;

  function Eigen_vectors_extern_function
      "Extern function that gives eigen vectors of complex 3x3 matrices"
    input Real tab[:,:];
    output Real tab_res[size(tab,1),2*size(tab,2)];
    external "C"
    fct_tab_c(tab,tab_res,size(tab_res,1),size(tab_res,2))
      annotation(Include="#include <Eigen_Library_HEADER.h>",Library="Eigen_Library");
    end Eigen_vectors_extern_function;

 
  class testofEigenLibrary
     Real ReA[3,3] = [1,1,2;4,3,2;1,2,4];
     Real ImA[3,3] = [2,2,6;4,5,4;3,2,1];
     Real A[3,6] = [ReA,ImA];
     Real res[3,12];
     algorithm
     res := Eigen_vectors_extern_function(A);
  end testofEigenLibrary;

end PersoEigenLibrary;

Then, I instantiate the class "testofEigenLibrary", defined previously in the package:

class testPersoEigenLibrary
import PersoEigenLibrary.*;
testofEigenLibrary b;
end testPersoEigenLibrary;


My problem is that I get the following messages:





Hence, my questions are the following:
- Where should I store the directory containing my header file,  my C and C++ functions, and their .lib file?
- How should I organize this directory?
- Is my header file correct?
- Do I need to load this directory as a Library? If yes, how?

By advance, thank you for your help.

William