In Microsoft Excel 5.0, all functionality in the XLM language was mirrored in the VBA language. Since the C API is based directly upon XLM, this meant that all functionality in Excel 5.0 was also available from the C API. This continued to be the case with Microsoft Excel 95. Starting with Microsoft Excel 97, however, there is quite a bit of functionality that is not exposed to XLM and consequently the C API. If you need access to some of this functionality from your C code, you will need to use the OLE Automation interface. This trend will continue as new versions of Microsoft Excel are released.