path

static VALUE
foletypelib_path(VALUE self)
{
    TLIBATTR *pTLibAttr;
    int len = 0;
    HRESULT hr = S_OK; 
    BSTR bstr;
    LCID lcid = cWIN32OLE_lcid;
    VALUE path;
    struct oletypelibdata *ptlib;
    ITypeLib *pTypeLib;

    Data_Get_Struct(self, struct oletypelibdata, ptlib);
    pTypeLib = ptlib->pTypeLib;
    hr = pTypeLib->lpVtbl->GetLibAttr(pTypeLib, &pTLibAttr);
    if (FAILED(hr)) {
        ole_raise(hr, eWIN32OLERuntimeError, "failed to get TLIBATTR information");
    }
    hr = QueryPathOfRegTypeLib(&pTLibAttr->guid, 
                               pTLibAttr->wMajorVerNum,
                               pTLibAttr->wMinorVerNum,
                               lcid,
                               &bstr);
    if (FAILED(hr)) {
        pTypeLib->lpVtbl->ReleaseTLibAttr(pTypeLib, pTLibAttr);
        ole_raise(hr, eWIN32OLERuntimeError, "failed to QueryPathOfRegTypeTypeLib");
    }

    pTypeLib->lpVtbl->ReleaseTLibAttr(pTypeLib, pTLibAttr);
    path = WC2VSTR(bstr);
    return rb_enc_str_new(StringValuePtr(path), strlen(StringValuePtr(path)), cWIN32OLE_enc);
}