identifier of on_change function is not defined in cv::createButton()

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Hello,

I'ver got a problem with the initalisation of the required function pionter "on_change" in

 createButton(const string& bar_name, ButtonCallback on_change, void* userdata=NULL, int type=CV_PUSH_BUTTON, bool initial_button_state=0 ).

The compiler gives the error that the identifiers is not defined. Although, I initalised it just like the "CallBackFunc" which is working fine.

Does somebody has an idea where the problem is?

Thank you!

This is my code:

void On_click(int state, void *pointer)
{
    printf("Check!");
}


void CallBackFunc(int event, int x, int y, int flags, void* userdata)
{
    if (event == EVENT_LBUTTONDOWN)
    {
        cout << "Left button of the mouse is clicked - position (" << x << ", " << y << ")" << endl;
    }
    else if (event == EVENT_RBUTTONDOWN)
    {
        cout << "Right button of the mouse is clicked - position (" << x << ", " << y << ")" << endl;
    }
    else if (event == EVENT_MBUTTONDOWN)
    {
        cout << "Middle button of the mouse is clicked - position (" << x << ", " << y << ")" << endl;
    }
    else if (event == EVENT_MOUSEMOVE)
    {
        cout << "Mouse move over the window - position (" << x << ", " << y << ")" << endl;

    }
}

int main(int argc, char** argv)
{

    // Read image from file 
    Mat img = imread("lena.tif");

    //if fail to read the image
    if (img.empty())
    {
        cout << "Error loading the image" << endl;
        return -1;
    }
    //Create a window
    namedWindow("My Window", CV_WINDOW_NORMAL);
    char* nameb1 = "button1";
    cv::createButton(nameb1, On_click, nameb1, CV_CHECKBOX, 1);
    //set the callback function for any mouse event
    setMouseCallback("My Window", CallBackFunc, NULL);

    //show the image
    imshow("My Window", img);

    // Wait until user press some key
    waitKey(0);

    return 0;

}