title: creating checkbox/button in opencv
body: <blockquote>
    <p>The error while creating a button in opencv 
    argument of type 'void (Window::)(int, void*)' does not match 'cv::ButtonCallback {aka void (<em>)(int, void</em>)}'</p>
  </blockquote>
  
  <pre><code>class Window{
      void ChecKBox(int state, void* val){
           // do nothing for now
           return;
      }
  public:
      void createCheckbox(){
          cv::createButton(checkboxname, CheckBox, NULL, CV_CHECKBOX, 0);
      }
  };
  
  int main(){
      Window w;
      w.createCheckBox();
  }
  </code></pre>
  
  <p>I can't seem to find the fix to this problem.</p>