i am trying to build an app using c# to make the GUI and c++ to do the job especially the openGl functions ,however i build the dll and i tried to use a normal function and it works
but when i create another fucntions that summon another function who use glut instruction when i run the code i get this error ,here is the c# code:

  public class Program
    {
        public const string CppFunctions = @"......DebugProject2.dll";
        [DllImport(CppFunctions, CallingConvention = CallingConvention.Cdecl)]
        public static extern void nS();
#pragma warning restore CS0626 // Method, operator, or accessor is marked external and has no attributes on it
        [STAThread]
        static void Main()
        {
            nS();
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);
            Application.Run(new Form1());
            

        }
    }

and the c++ code:

#include <GL/glut.h>

#define func _declspec(dllexport)

void draw() {
    glClearColor(1, 1, 1, 0);
    glClear(GL_COLOR_BUFFER_BIT);
    glFlush();
}

void sheet() {
    glutInit(0, NULL);
    glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB);
    glutInitWindowPosition(80, 80);
    glutInitWindowSize(640, 480);
    glutCreateWindow("program");
    gluOrtho2D(0, 640, 0, 480);
    glutDisplayFunc(draw);
    glutMainLoop();
}
extern "C" {    
    func void nS() {
        sheet();
    }
}

when i run it it jumps to glut.h and show an arow on:

static void APIENTRY glutInit_ATEXIT_HACK(int *argcp, char **argv) { __glutInitWithExit(argcp, argv, exit); }

i know that there is opentk i just fell like i am way stronger in c++ opengl than anything else that the reason why i don’t want to switch to opentk