C / C++ / MFC

When a file is opened with the "a" or "a+" access type, all write 
operations occur at the end of the file. The file pointer can be 
repositioned using fseek or rewind but is always moved back to the end of 
the file before any write operation is carried out. Thus, existing data 
cannot be overwritten.

When the "r+", "w+", or "a+" access type is specified, both reading and 
writing are allowed (the file is said to be open for "update"). However,
 when you switch between reading and writing, there must be an intervening 
fflush, fsetpos, fseek, or rewind operation. The current position can be 
specified for the fsetpos or fseek operation, if desired.

"r+"

Opens for both reading and writing. (The file must exist.)

"w+"

Opens an empty file for both reading and writing. If the given file exists, its contents are destroyed.

Mark Salsbery wrote:

You'll have to remove all uses of MFC classes

Mark Salsbery wrote:

The OP stated "by getting a rid of any reference to MFC" so I answered accordingly.

   // In the class definition
   CImageList m_dialogToolbarImageList;
...
   // In constructor...(substitute an appropriate background/transparent COLORREF)
   CBitmap bitmap;
   bitmap.LoadBitmap(IDB_BITMAP4);
   m_dialogToolbarImageList.Create(16, 15, ILC_COLOR24|ILC_MASK, 3, 1);
   m_dialogToolbarImageList.Add(&bitmap, RGB(0x00,0xFF,0x00));
...
   // In OnCreate or OnInitDialog
   m_dialogToolbar.Create(this);
   m_dialogToolbar.GetToolBarCtrl().SetImageList(&m_dialogToolbarImageList);
   m_dialogToolbar.SetSizes(CSize(23,21), CSize(16,15));
   m_dialogToolbar.SetButtons(toolBarButtons,3);

levelboy wrote:

even if the bmp is 24 bit, it shows it, but in 16 colors