BSTRからC文字列への変換

VC COM 
  // BSTR to C String

  BSTR bstrStart;

  bstrStart = GetBSTR();

  TCHAR szFinal[255];

  // direct conversion from BSTR to LPCTSTR only works
  // in Unicode
  _stprintf(szFinal, _T("%s"), (LPCTSTR)bstrStart);
  AfxMessageBox(szFinal);

  _bstr_t bstrIntermediate(bstrStart);    // convert to
                                          // _bstr_t
  CString strFinal;

  // you have to go through _bstr_t to have it work in ANSI
  // and Unicode
  _stprintf(szFinal, _T("%s"), (LPCTSTR)bstrIntermediate);

  // Or, using MFC

  strFinal.Format(_T("%s"), (LPCTSTR)bstrIntermediate);

  AfxMessageBox(strFinal);

ネタ元