The EM_SETOLECALLBACK message gives a rich edit control an IRichEditOleCallback object that the control uses to get OLE-related resources and information from the client.
EM_SETOLECALLBACK
wParam = 0;
lParam = (LPARAM) (IRichEditOleCallback FAR *) lpObj;
Returns a nonzero value if successful or zero otherwise.
Windows NT: Requires version 3.51 or later.
Windows: Requires Windows 95 or later.
Windows CE: Unsupported.
Header: Declared in richedit.h.
Rich Edit Controls Overview, Rich Edit Messages