HOWTO: Determine the Version of a Microsoft Excel Workbook

• Microsoft Visual C++, 32-bit Editions, version 5.0
• Microsoft Excel 97 for Windows
• Microsoft Excel for Windows 95, versions 7.0, 7.0a
• Microsoft Excel for Windows, versions 5.0, 5.0a, 5.0c

SUMMARY

This article demonstrates how to determine the version of a Microsoft Excel Workbook (.xls).

MORE INFORMATION

Microsoft Excel saves data using structured storage. In particular, it creates a data stream called "Workbook" (previously just "Book") where it saves the contents starting with a BOF (beginning of file) record. This record contains useful attributes of the workbook, as well as the version. The following Microsoft Visual C++ code demonstrates how to open the file, read it, and return the version number based on the BOF.

1. Create a new "Win32 Console Application" in Microsoft Developer Studio.

2. Add a C++ Source File (.cpp) to the project and add the following code to the source file:

         #include <windows.h>
         #include <iostream.h>   // My additions
   
         // BOF record from Microsoft Excel
         typedef struct _xlbof
         {
            char bofMarker; // Should be 0x09
   
            char vers;  // Version indicator for biff2, biff3, and biff4
                        // = 0x00 -> Biff2
                        // = 0x02 -> Biff3
                        // = 0x04 -> Biff4
                        // = 0x08 -> Biff5/Biff7/Biff8
   
            char skip[2]; // Unspecified
   
            short int vers2;  // Version number
                              // 0x0500 -> Biff5/Biff7
                              // 0x0600 -> Biff8
   
            short int dt;     // Substream type (not used in this example)
   
            short int rupBuild;  // Internal build identifier
            short int rupYear;   // Internal Build year
         } XLBOF;
   
   
         //* XLVersionFromFile() ******************************************
         //* Returns
         //*        n for BiffN
         //*   i.e. 8 for Biff8 (Microsoft Excel 97)
         //*
         //*        Negative if an error occurs
         //****************************************************************
   
         int XLVersionFromFile(char *filename) {
            // Translate filename to Unicode
            WCHAR wcFilename[1024];
            int i = mbstowcs(wcFilename, filename, strlen(filename));
            wcFilename[i] = 0;
   
            IStorage *pStorage;
            HRESULT hr;
            XLBOF xlbof;
   
            // Open the document as an OLE compound document
            hr = ::StgOpenStorage(wcFilename, NULL,
                       STGM_READ | STGM_SHARE_EXCLUSIVE, NULL, 0, &pStorage);
   
            if(!FAILED(hr)) {
               // Open the data-stream where Microsoft Excel stores the data
               IStream *pStream;
               hr = pStorage->OpenStream(L"Workbook", NULL,
                       STGM_READ | STGM_SHARE_EXCLUSIVE, 0, &pStream);
   
               // If "Workbook" does not exist, try "Book"
               if(FAILED(hr)) {
                  hr = pStorage->OpenStream(L"Book", NULL,
                       STGM_READ | STGM_SHARE_EXCLUSIVE, 0, &pStream);
               }
               if(!FAILED(hr)) {
                  // Read the relevant BOF information
                  DWORD dwCount; // bytes read
                  pStream->Read(&xlbof, sizeof(XLBOF), &dwCount);
   
                  // Let go of the IStream pointer
                  pStream->Release();
               }
               else return -2;
   
               // Let go of the IStorage pointer
               pStorage->Release();
             }
             else return -1;
   
             // Determine which version to return
             if(xlbof.vers != 0x08) return (xlbof.vers + 4) / 2;
             else {
                switch(xlbof.vers2) {
                  case 0x0500:  // Either Biff5 or Biff7
                     // Biff7's rupYear is at least 1994
                     if(xlbof.rupYear < 1994) return 5;
   
                     // Check for specific builds of Microsoft Excel 5
                     switch(xlbof.rupBuild) {
                        case 2412: // XL5a
                        case 3218: // XL5c
                        case 3321: // NT XL5
                           return 5;
                        default:
                           return 7;
                     }
   
                case 0x0600:  return 8;
                }
             }
   
             // Version not recognized. Perhaps there is a newer version.
             return -3;
         }
   
         void main()
         {
            int iretVal = 0;
            iretVal = XLVersionFromFile("C:\\Test.xls");
                                        //Adapt the filename to your example
            cout << "The Excel Version is " << iretVal << "\n\n\r";
            return;
         }
   
   

3. In the main()function, you may need to modify the path and filename of the Microsoft Excel workbook in the following line of code:

         iretVal = XLVersionFromFile("C:\\Test.xls");
   

REFERENCES

Microsoft Visual C++ Help, version 5.0; search on “structured storage”

Microsoft Developer’s Network (MSDN); search on “structured storage”, “Microsoft Excel file format”, BOF”, “beginning of file”

Microsoft Excel 97 Developer's Kit (ISBN: 1-57231-498-2); search on “Microsoft Excel file format”, BOF”, “beginning of file”