void SetWindowText( const char FAR* lpString );
lpString
Points to a CString or null-terminated string.
Sets the caption title (if one exists) to the specified text. If the CWnd is a control, the SetWindowText member function sets the text within the control instead of within the caption. This function sends a WM_SETTEXT message to CWnd.
CWnd::GetWindowText, ::SetWindowText