***************
*** 253,259 ****
  
  /**************************************** main() ********************/
  
- void main(int argc, char* argv[])
  {
    /****************************************/
    /*   Initialize GLUT and create window  */
--- 253,259 ----
  
  /**************************************** main() ********************/
  
+ int main(int argc, char* argv[])
  {
    /****************************************/
    /*   Initialize GLUT and create window  */
***************
*** 371,375 ****
    /**** Regular GLUT main loop ****/
    
    glutMainLoop();
  }
  
--- 371,376 ----
    /**** Regular GLUT main loop ****/
    
    glutMainLoop();
+   return 0;
  }