C#

[StructLayout(LayoutKind.Sequential)]
public class MY_IMAGE
{

  public int width; // image width
  public int height; // image height
  public int info; // bit-count (1,4,8 bit)
  public IntPtr pbuf; // image buffer
}

[DllImport("scandll.dll")]
private extern static int WScanSelectBuf(MY_IMAGE image_down, MY_IMAGE image_up, int select);

public static int ScanSelectBuf(ref MY_IMAGE image_down, ref MY_IMAGE image_up, int select)
{  
  return WScanSelectBuf(image_down, image_up, select);
}

public static int ScanSelectBuf(MY_IMAGE image_down, MY_IMAGE image_up, int select)
{  
  return WScanSelectBuf(image_down, image_up, select);
}

econner wrote:

So, I do not have acces to fill the buffer with a byte[]. This should be happening from caling the method.

[StructLayout(LayoutKind.Sequential)]
public class MY_IMAGE
{
    public int width;
    public int height;
    public int info;
    public IntPtr pbuf; // image buffer
}


[DllImport("scandll.dll")]
private extern static int WScanSelectBuf(IntPtr image_down, IntPtr image_up, int select);

public static int ScanSelectBuf(MY_IMAGE image_down, MY_IMAGE image_up, int select)
{

    GCHandle image_downHandle = GCHandle.Alloc(image_down, GCHandleType.Pinned);
    GCHandle image_upHandle = GCHandle.Alloc(image_up, GCHandleType.Pinned);

    int ret = WScanSelectBuf(image_downHandle.AddrOfPinnedObject(),
                                  image_upHandle.AddrOfPinnedObject(), select);

//CRASHES HERE WITH ERROR:
//Attempted to read or write protected memory.
//This is often an indication that other memory is corrupt.

    image_downHandle.Free();
    image_upHandle.Free();

    return ret;
}

MY_IMAGE img1 = new MY_IMAGE();
MY_IMAGE img2 = new MY_IMAGE();

int nWidth = 864;
int nHeight = 1000;

img1.width = nWidth;
img1.height = nHeight;
img1.info = 8; // 8bit
//img1.pbuf = new byte[2 *nWidth * nHeight];


img2.width = nWidth;
img2.height = nHeight;
img2.info = 8; // 8bit
//img2.pbuf = new byte[2 * nWidth * nHeight];

//HOW TO DEFINE BYTE[] AND PIN AND THEN ASSIGN TO BUFFER?????

ret = ScanSelectBuf(img1, img2, 0);

MY_IMAGE img1 = new MY_IMAGE();
MY_IMAGE img2 = new MY_IMAGE();

// Initialize the other fields, I mean, width, height and info
// Then create the byte[] arrays
// with the size given by the documentation
byte[] buffer1 = new byte[2*img1.width*img1.height];
byte[] buffer2 = new byte{2*img2.width*img2.height];

// Pin these two arrays in the managed heap
GCHandle bufferHandle1 = GCHandle.Alloc(buffer1, GCHandleType.Pinned);
GCHandle bufferHandle2 = GCHandle.Alloc(buffer2, GCHandleType.Pinned);

// Set the address of the buffers to each pbuf field
img1.pbuf = bufferHandle1.AddrOfPinnedObject();
img2.pbuf = bufferHandle2.AddrOfPinnedObject();

// And now we can make the P/Invoke call
int ret = WScanSelectBuf(img1, img2, select);

// Do not forget to free the handles
bufferHandle1.Free();
bufferHandle2.Free();

// Here you should have the pixel information in the buffer1 and buffer2 arrays

WScanSelectBuf(img1, img2, select)   (MY_IMAGE)
WScanSelectBuf(ref img1, ref img2, select)  (ref of MY_IMAGE)
WScanSelectBuf(img1, img2, select)   (IntPtr)

img1.pbuf = Marshal.UnsafeAddrOfPinnedArrayElement(buffer1, 0);
img2.pbuf = Marshal.UnsafeAddrOfPinnedArrayElement(buffer2, 0);

[DllImport("scandll.dll")]
private extern static int WScanSelectBuf(MY_IMAGE image_down, MY_IMAGE image_up, int select);


public static int ScanSelectBuf(MY_IMAGE image_down, MY_IMAGE image_up, int select)
{
   return WScanSelectBuf(image_down, image_up, select);
}


int nWidth = 100;
int nHeight = 200;

img1.width = nWidth;
img1.height = nHeight;
img1.info = 8; // 8bit

img2.width = nWidth;
img2.height = nHeight;
img2.info = 8; // 8bit

byte[] buffer1 = new byte[2 * img1.width * img1.height];
byte[] buffer2 = new byte[2 * img2.width * img2.height];

           
// Pin these two arrays in the managed heap
GCHandle bufferHandle1 = GCHandle.Alloc(buffer1, GCHandleType.Pinned);
GCHandle bufferHandle2 = GCHandle.Alloc(buffer2, GCHandleType.Pinned);

// Set the address of the buffers to each pbuf field
//img1.pbuf = bufferHandle1.AddrOfPinnedObject();
//img2.pbuf = bufferHandle2.AddrOfPinnedObject();

img1.pbuf = Marshal.UnsafeAddrOfPinnedArrayElement(buffer1, 0);
img2.pbuf = Marshal.UnsafeAddrOfPinnedArrayElement(buffer2, 0);


// And now we can make the P/Invoke call
ret = ScanSelectBuf(img1, img2, 0);

// Do not forget to free the handles
bufferHandle1.Free();
bufferHandle2.Free();

econner wrote:

Any suggestions would be appreciated.