Attempted to read or write protected memory. This is often an indication that other memory is corrupt. in C++ Dll

Question

i have a problem in code. When i compile program so it write "AccessViolationException was unhandle" "Attempted to read or write protected memory. This is often an indication that other memory is corrupt."

C# code:

    [DllImport(@"DLLmedian.dll")]
    public static extern SCIOX_bitmap median(SCIOX_bitmap image, int size);

    private void button2_Click(object sender, EventArgs e)
    {

        string url = @"img.png";
        pictureBox1.Load(url);
        SCIOX_bitmap a;

        a.height = pictureBox1.Height;
        a.width = pictureBox1.Width;
        var source = new BitmapImage(new System.Uri(url));
        int b = source.Format.BitsPerPixel;
        a.color_depth = (4 * b) * b;
        a.points = pictureBox1.Handle;
        a = median(a, 8);      

    }

    public struct SCIOX_bitmap
    {
        public int width;
        public int height;
        public int color_depth;
        public IntPtr points;
    };

C++ code:

SCIOX_bitmap __stdcall median(SCIOX_bitmap image, int size)
{   
    SCIOX_bitmap finMap;            
    finMap.width = image.width;
    finMap.height = image.height;
    finMap.color_depth = image.color_depth;
    finMap.points = new int[finMap.height*finMap.width];

    int *valArr = new int[size*size]


    for(int i=0; i<image.width; i++)
        for(int j=0; j<image.height; j++)
        {
            for(int k=0,n=0; k<size; k++)
                for(int l=0; l<size; l++,n++)
                      valArr[n] = image.points[((i-size/2+k+image.width)%image.width)*image.height + (j-size/2+l+image.height)%image.height];
                                     **//AccessViolationException was unhandle**
            mysort(valArr, size*size);  
            if(size*size%2 == 1)
                finMap.points[i*finMap.height + j] = valArr[size*size/2];
            else                    
                finMap.points[i*finMap.height + j] = (valArr[size*size/2-1] + valArr[size*size/2]) / 2;
        }

        return finMap;
}

   struct SCIOX_bitmap{
        int width;
        int height;
        int color_depth;
        int* points;
    };

Anybody help me please ?

Sorry I forgot SCIOX_bitmap is struct. SCIOX_bitmap is also in c++ code

public struct SCIOX_bitmap
    {
        public int width;
        public int height;
        public int color_depth;
        public IntPtr points;
    };

What is SCIOX_Bitmap? Are you obeying the Rule of Three when it comes to the dynamic memory stored within it? — The Forest And The Trees, Feb 21 '14 at 10:09

score 0 · Answer 1 · edited May 23 '17 at 10:31

It appears to be that you're accessing the Handle of a PictureBox class as if it were a handle to the Image. That isn't correct, the Handle property is a handle to the Control.

If you want to get a Handle to the Image itself, you'll need to convert it to a Bitmap and then use GetHBitmap()

Bitmap bitmap = new Bitmap(pictureBox1.Image);
a.points = bitmap.GetHBitmap();

Additionally, I would recommend that you look into the Rule of Three for your C++ code, as you're going to leak the memory declared for the points buffer on each call to median.

Attempted to read or write protected memory. This is often an indication that other memory is corrupt. in C++ Dll

1 Answers1