C API Functions That Can Be Called Only from a DLL or XLL
Applies to: Excel 2013 | Office 2013 | Visual Studio
The C API provides 15 Microsoft Excel callback functions that can only be called by using the Excel4, Excel4v, Excel12, or Excel12v functions (or by one of these functions indirectly using the Framework functions Excel or Excel12f). This means they can only be called from a DLL or XLL.