How to use Mat::forEach position parameter?

edit

I want to know the pixel id of the Mat element using cv::Mat::forEach position parameter. I read the documentation here and tried the following code!

Code:

typedef cv::Point_<uchar> Pixel;
struct Operator {
    void operator ()(Pixel &pixel, const int * position) const 
    {           
        cout << format("[%d,%d]= %d \n",position[0],position[1],(int)pixel.x);      
    }
};

int main( int argc, char* argv[])
{    
    Mat mTest(Size(3, 2), CV_8UC1,Scalar(0));   
    randn(mTest,Scalar(125),Scalar(125));

    cout<< format (" Size : %d , %d \n",mTest.rows,mTest.cols);

    for (int Rows = 0; Rows < mTest.rows; Rows++)
    {
        for (int Cols = 0; Cols < mTest.cols; Cols++)
        {
            cout << format("[%d,%d]= %d \t",Rows,Cols,mTest.at<uchar>(Rows,Cols));
        }
        cout << "\n";
    }
    cout << "\n\n";

    mTest.forEach<Pixel>(Operator());

    waitKey();

    return 0;
}

Output:

 Size : 2 , 3
[0,0]= 125      [0,1]= 145      [0,2]= 37
[1,0]= 71       [1,1]= 255      [1,2]= 90


[0,0]= 125
[1,0]= 71
[0,1]= 37
[0,2]= 255
[1,1]= 90
[1,2]= 0
Press any key to continue . . .

As you can see there is a mismatch in the Actual Pixel ID and the Position parameter ID! So how to use the position parameter correctly?

Note: I've just noted that there is a different method described in the documentation

i.e forEachWithPosition but it is not available now?