COM Method implementation to return an array of strings

COM Return Array of Strings

STDMETHODIMP CMyClass::GetThings(VARIANT* returnThings)
{
  HRESULT hr = S_OK;
  SAFEARRAY FAR* safeArray;
  SAFEARRAYBOUND safeArrayBound;

  if (m_thing != NULL)
  {
    std::set<const char *>::iterator it;
    std::set<const char *> things = m_thing->GetThings();

    // Initialize the bounds of the SafeArray
    safeArrayBound.lLbound = 0;
    safeArrayBound.cElements = things.size();

    safeArray = SafeArrayCreate(
      VT_BSTR,           // Array of BSTR
      1,                 // 1 dimension
      &safeArrayBound);  // Initialize bounds

    LONG i = 0;

    // Add the names to the array
    for (i = 0, it = things.begin(); it != things.end(); it++, i++)
    {
      size_t length = strlen(*it) + 1;
      OLECHAR *oleThing = new OLECHAR[length];

      mbstowcs(oleThing, *it, length);

      hr = SafeArrayPutElement(safeArray, &i, SysAllocString(oleThing));

      delete oleThing;

      // Quit any of the operations fail
      if (FAILED(hr))
        break;
    }

    if (SUCCEEDED(hr))
    {
      returnThings->vt = VT_ARRAY | VT_BSTR;
      returnThings->parray = safeArray;
    }
  }

  return hr;
}