Trying to clip the cursor to my window isn't working?

I'm trying to make the windows cursor stay inside my window. I'm using freeglut and C++ Everything is working great so far, except for the part where I try to use ClipCursor to keep the cursor locked in my window, it moves freely like the command wasn't even called. It worked fine in a project I have that doesn't use glut at all, but I wanted to try glut out.

Here's the code that's relevant:

 int main(int argc, char* argv[])
 {
      glutInit(&argc, argv);
      glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGBA);
      glutInitWindowSize(WIDTH,HEIGHT);
      glutInitWindowPosition(50,50);
      glutCreateWindow("Indie Game开发者_StackOverflow中文版 01");
      glewInit();
      GLenum err = glewInit();
      if(GLEW_OK != err) {
         cout << "glewInit failed, aborting." << endl;
         exit(1);
      }
      cout << "Status: Using GLEW " << glewGetString(GLEW_VERSION) << endl;
      cout << "OpenGL version " << glGetString(GL_VERSION) << " supported" << endl;

      HWND hwnd;
      hwnd = FindWindow("GLUT","Indie Game 01");
      RECT r;
      GetWindowRect(hwnd,&r);
      ClipCursor(&r);

      init();
      glutDisplayFunc(display);
      glutMouseFunc(mouse);
      glutKeyboardFunc(keyboard);
      glutReshapeFunc(reshape);

      glutMainLoop();
      return 0;
 }

I don't get why the ClipCursor isn't working :/ any help is greatly appreciated!

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FindWindow must be failing. Try passing 0 as the first parameter.