c++ - WMI SoftwareLicensingProduct class doesn't show Partial Product Key for MS Office on some systems ( Windows 10) -

using wmi softwarelicensingproduct class fetching partial product key / license key microsoft product. compatible windows vista , above. still not able retrieve key ms office on few windows10 system, rest of systems, working expected.

code :

int _tmain(int argc, _tchar* argv[]) {

 hresult hres;  // initialize com. hres =  coinitializeex(0, coinit_multithreaded);  if (failed(hres)) {     cout << "failed initialize com library. "          << "error code = 0x"          << hex << hres << endl;     return 1;              // program has failed. }  // initialize  hres =  coinitializesecurity(     null,          -1,      // com negotiates service                       null,    // authentication services     null,    // reserved     rpc_c_authn_level_default,    // authentication     rpc_c_imp_level_impersonate,  // impersonation     null,             // authentication info      eoac_none,        // additional capabilities     null              // reserved     );   if (failed(hres)) {     cout << "failed initialize security. "          << "error code = 0x"          << hex << hres << endl;     couninitialize();     return 1;          // program has failed. }  // obtain initial locator windows management // on particular host computer. iwbemlocator *ploc = 0;  hres = cocreateinstance(     clsid_wbemlocator,                  0,      clsctx_inproc_server,      iid_iwbemlocator, (lpvoid *) &ploc);  if (failed(hres)) {     cout << "failed create iwbemlocator object. "         << "error code = 0x"         << hex << hres << endl;     couninitialize();     return 1;       // program has failed. }  iwbemservices *psvc = 0;  // connect root\cimv2 namespace // current user , obtain pointer psvc // make iwbemservices calls.  hres = ploc->connectserver(      _bstr_t(l"root\\cimv2"), // wmi namespace     null,                    // user name     null,                    // user password     0,                       // locale     null,                    // security flags                      0,                       // authority            0,                       // context object     &psvc                    // iwbemservices proxy     );                                if (failed(hres)) {     cout << "could not connect. error code = 0x"          << hex << hres << endl;     ploc->release();          couninitialize();     return 1;                // program has failed. }  cout << "connected root\\cimv2 wmi namespace" << endl;  // set iwbemservices proxy impersonation // of user (client) occurs. hres = cosetproxyblanket(     psvc,                         // proxy set    rpc_c_authn_winnt,            // authentication service    rpc_c_authz_none,             // authorization service    null,                         // server principal name    rpc_c_authn_level_call,       // authentication level    rpc_c_imp_level_impersonate,  // impersonation level    null,                         // client identity     eoac_none                     // proxy capabilities      );  if (failed(hres)) {     cout << "could not set proxy blanket. error code = 0x"           << hex << hres << endl;     psvc->release();     ploc->release();          couninitialize();     return 1;               // program has failed. }   // use iwbemservices pointer make requests of wmi.  // make requests here:  // example, query running processes ienumwbemclassobject* penumerator = null;   hres = psvc->execquery(     bstr_t("wql"),      bstr_t("select * softwarelicensingproduct"),     wbem_flag_forward_only | wbem_flag_return_immediately,      null,     &penumerator);   if (failed(hres)) {     cout << "query processes failed. "          << "error code = 0x"           << hex << hres << endl;     psvc->release();     ploc->release();          couninitialize();     return 1;               // program has failed. } else {      iwbemclassobject *pclsobj;     ulong ureturn = 0;      while (penumerator)     {         hres = penumerator->next(wbem_infinite, 1,              &pclsobj, &ureturn);          if(0 == ureturn)         {             break;         }          variant vtprop;          // value of name property         hres = pclsobj->get(l"name", 0, &vtprop, 0, 0);         wcout << "process name : " << vtprop.bstrval << " ";         variantclear(&vtprop);           variant vtprop1;          // value of partialproductkey property         hres = pclsobj->get(l"partialproductkey", 0, &vtprop1, 0, 0);         if (vt_null != vtprop1.vt)             wcout << ": " << vtprop1.bstrval << endl;         else             wcout<<endl;         variantclear(&vtprop1);     }  } getch(); // cleanup // ========  psvc->release(); ploc->release();      couninitialize();  return 0;   // program completed. 

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