How To Determine Which Version of Excel Wrote a Workbook

   #include <windows.h>
   #include <stdio.h>

   int XLVersionThatWroteFile(char *filename) {
      // Translate filename to Unicode
      WCHAR wcFilename[1024];
      int i = mbstowcs(wcFilename, filename, strlen(filename));
      wcFilename[i] = 0;

      // Open the document as an OLE compound document
      IStorage *pStorage;
      HRESULT hr;
      hr = ::StgOpenStorage(wcFilename, NULL,
                 STGM_READ | STGM_SHARE_EXCLUSIVE, NULL, 0, &pStorage);

      if(FAILED(hr)) return 0;
      // 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)) {
         pStorage->Release();
         return 0;
      }

      // Get rupBuild & rupYear
      short rupBuild, rupYear;
      LARGE_INTEGER off;
      ULARGE_INTEGER newPos;
      off.QuadPart = 8;
      pStream->Seek(off, STREAM_SEEK_SET, &newPos);
      DWORD bytesRead;
      pStream->Read(&rupBuild, 2, &bytesRead);
      pStream->Read(&rupYear, 2, &bytesRead);

      // Let go of the IStorage pointer
      pStorage->Release();

      // Excel 8.0's rupyear = 1996
      if(rupYear == 1996) return 8;
      // Excel 9.0 comes after Excel 8.0...
      if(rupYear > 1996) return 9;
      // Excel 5.0's rupyear < 1994
      if(
         (rupYear < 1994) ||
         // Excel 5.0 & 7.0 have rupYear=1994 for some versions...
         (rupBuild == 2412) || (rupBuild == 3218) || (rupBuild == 3321)
      ) return 5;
      // All that's left is Excel 7.0
      return 7;

   }

   void main(int argc, char **argv) {
      if(argc != 2) {
         printf("Usage: XLVER filename.xls");
      }
      else {
         printf("Excel version = %d", XLVersionThatWroteFile(argv[1]));
      }
   }