C / C++ / MFC

HBITMAP hbmp1 = NULL, hbmp2 = NULL;
BITMAP bmp1, bmp2;
.
.
//load the bitmaps in hbmp1 and hbmp2
.
.
GetObject(hbmp1, sizeof(BITMAP), &bmp1); //get the first bitmap's data
GetObject(hbmp2, sizeof(BITMAP), &bmp2); //get the first bitmap's data

//if they differ in color depth or dimenstions they mismatch
if(bmp1.bmBitsPixel != bmp2.bmBitsPixel ||
	bmp1.bmHeight !=  bmp2.bmHeight || bmp1.bmWidth !=  bmp2.bmWidth)
	return 0;
else
{
        //get the bits of both bitmaps
	LPBYTE data1 = (LPBYTE)bmp1.bmBits,
		data2 = (LPBYTE)bmp2.bmBits;

        //the number of bytes per width
	DWORD bmWidth = bmp1.bmWidth * (bmp1.bmBitsPixel / 8);

	//somthing is wrong with bmWidthBytes member in Win9x and Win2k
        //so it's better to calculate the offset yourself
	DWORD bmWidthBytes = bmWidth + (4 - bmWidth % 4) * bool(bmWidth % 4);

        //number of bytes in data1 and data2
	DWORD bytesize = bmp1.bmHeight * bmWidthBytes;
        //compare the two bitmap's bits
	if(memcmp(data1, data2, bytesize) == 0)
		return 1;
}

GetDIBColorTable() 

  CMainFrame *pFrame = (CMainFrame*)AfxGetMainWnd();
  CChildFrame *pChild = (CChildFrame *) pFrame->GetActiveFrame();

  CRect WndRect;

      //:-D thx Schlaubi
  CWnd* pMDIClientWnd = CWnd::FromHandle(pFrame->m_hWndMDIClient);


  GetClientRect(WndRect);

  CBitmap     bitmap;
  CDC         *dcP;
  CDC         memDC;
  CRect       rect;

  dcP = GetWindowDC();
  memDC.CreateCompatibleDC(dcP);

 bitmap.CreateCompatibleBitmap(dcP,WndRect.right, WndRect.bottom);


 CBitmap *pOldBitmap = memDC.SelectObject(&bitmap);
 memDC.BitBlt(0, 0, WndRect.right,WndRect.bottom, dcP,2 , 2, SRCCOPY);

OpenClipboard();
 EmptyClipboard();

 SetClipboardData(CF_BITMAP, bitmap.GetSafeHandle());

 CloseClipboard();
 memDC.SelectObject(pOldBitmap);

    HBITMAP hbmp1 = (HBITMAP) SignatureBitmap;
    HBITMAP hbmp2 = (HBITMAP) bitmap;
    BITMAP bmp1, bmp2;
  //load the bitmaps in hbmp1 and hbmp2
    GetObject(hbmp1, sizeof(BITMAP), &bmp1);
  //get the first bitmap's data
    GetObject(hbmp2, sizeof(BITMAP), &bmp2);
  //get the first bitmap's data
  //if they differ in color depth or dimenstions they mismatch
    if(bmp1.bmBitsPixel != bmp2.bmBitsPixel ||	bmp1.bmHeight != bmp2.bmHeight || bmp1.bmWidth !=  bmp2.bmWidth)
	AfxMessageBox("prob");
else
{
	//get the bits of both bitmaps	
	LPBYTE data1 = (LPBYTE)bmp1.bmBits,		
		data2 = (LPBYTE)bmp2.bmBits;
	//the number of bytes per width	
	DWORD bmWidth = bmp1.bmWidth * (bmp1.bmBitsPixel / 8);
	//somthing is wrong with bmWidthBytes member in Win9x and Win2k
	//so it's better to calculate the offset yourself
       DWORD bmWidthBytes = bmWidth + (2 - bmWidth % 2) * bool(bmWidth % 2);
	//number of bytes in data1 and data2
	DWORD bytesize = bmp1.bmHeight * bmWidthBytes;
	//compare the two bitmap's bits	
	if(memcmp(data1, data2, bytesize) == 0)
		AfxMessageBox("goooooood");

	bitmap.Detach();
}

CDC         *dcP;
CDC         memDC;
CRect       WndRect;

dcP = GetWindowDC();
GetWindowRect(WndRect); //the window rect is the rect of the whole window
                            //while the client rect is of the client area only

CImage im; //CImage object
    //this is to create a DIB using CImage, the parameters are width, height,
    //color depth
im.Create(WndRect.Width(), WndRect.Height(), 24);
    //CImage::GetDC() return an HDC to the bitmap so you can use it
    //as any other dc
memDC.Attach(im.GetDC()); //attach the HDC into the memDC object
    //blit the window DC
memDC.BitBlt(0, 0, WndRect.right,WndRect.bottom, dcP,2 , 2, SRCCOPY);
memDC.Detach(); //detach the image HDC to prevent its destruction
im.ReleaseDC(); //this is needed for every call to GetDC()
    HBITMAP hbmp = im.Detach(); //you now have handle to DIB ready for use

BITMAP bmp1, bmp2;

GetObject(hbmp, sizeof(hbmp), &bmp1); //get the first bitmap's data
GetObject(hbmp, sizeof(hbmp), &bmp2); //get the first bitmap's data

if(memcmp(&bmp1, &bmp2, sizeof(bmp1) - sizeof(bmp1.bmBits)))
{
    AfxMessageBox("Prob");
}
else
{
    //get the bits of both bitmaps
    LPBYTE data1 = (LPBYTE)bmp1.bmBits,     data2 = (LPBYTE)bmp2.bmBits;
    //the number of bytes per width
    DWORD bmWidth = bmp1.bmWidth * (bmp1.bmBitsPixel / 8);
    //somthing is wrong with bmWidthBytes member in Win9x and Win2k
    //so it's better to calculate the offset yourself
    DWORD bmWidthBytes = bmWidth + (2 - bmWidth % 2) * bool(bmWidth % 2);
    //number of bytes in data1 and data2
    DWORD bytesize = bmp1.bmHeight * bmWidthBytes;
    //compare the two bitmap's bits
    if(memcmp(data1, data2, bytesize) == 0)
        AfxMessageBox("gooooooooooooooood");
}

if(data1 == 0)
   AfxMessageBox("Error in bitmap 1");
if(data2 == 0)
   AfxMessageBox("Error in bitmap 2");