Example Code for Updating the Schema Cache

The following C/C++ functions get the DNS name of the schema master (GetSchemaMasterDNSName) and update the schema cache at the schema master (UpdateSchemaMasterCache). To use these functions, call GetSchemaMasterDNSName to get the schema master DNS name, pass the schema master DNS name to UpdateSchemaMasterCache, call CoTaskMemFree on string containing the schema master DNS name.

For more information, see Updating the Schema Cache.

HRESULT UpdateSchemaMasterCache(LPOLESTR szSchemaMasterDNSName)
{
if (!szSchemaMasterDNSName)
   return E_POINTER;
HRESULT hr = E_FAIL;
IADs *pObject = NULL;
VARIANT var;
LPOLESTR szPath = new OLECHAR[MAX_PATH];
wcscpy_s(szPath,L"LDAP://");
wcscat_s(szPath,szSchemaMasterDNSName);
wcscat_s(szPath,L"/rootDSE");
hr = ADsOpenObject(szPath,
         NULL,
         NULL,
         ADS_SECURE_AUTHENTICATION, // Use Secure Authentication.
         IID_IADs,
         (void**)&pObject);
if (SUCCEEDED(hr))
{
  VariantInit(&var);
  var.vt = VT_I4;
  var.lVal = 1L;
  hr = pObject->Put(CComBSTR("schemaUpdateNow"), var);
  if (SUCCEEDED(hr))
  {
    hr = pObject->SetInfo();
    if (SUCCEEDED(hr))
      MessageBox(NULL,L"Updated",L"Extend Schema Wizard",MB_OK|MB_ICONEXCLAMATION);
    else
      MessageBox(NULL,L"Update Failed",L"Extend Schema Wizard",MB_OK|MB_ICONEXCLAMATION);
  }
}
if (pObject)
  pObject->Release();
 
return hr;
}
 
HRESULT GetSchemaMasterDNSName(LPOLESTR *pszSchemaMasterDNSName)
{
if (!pszSchemaMasterDNSName)
   return E_POINTER;
HRESULT hr = E_FAIL;
IADs *pObject = NULL;
IADs *pTempSchema = NULL;
IADs *pNTDS = NULL;
IADs *pServer = NULL;
BSTR bstrParent;
LPOLESTR szPath = new OLECHAR[MAX_PATH];
VARIANT var, varRole,varComputer;
hr = ADsOpenObject(L"LDAP://rootDSE",
         NULL,
         NULL,
         ADS_SECURE_AUTHENTICATION, // Use Secure Authentication.
         IID_IADs,
         (void**)&pObject);
if (SUCCEEDED(hr))
{
  hr = pObject->Get(CComBSTR("schemaNamingContext"), &var);
  if (SUCCEEDED(hr))
  {
    wcscpy_s(szPath,L"LDAP://");
    wcscat_s(szPath,var.bstrVal);
    hr = ADsOpenObject(szPath,
             NULL,
             NULL,
             ADS_SECURE_AUTHENTICATION, // Use Secure Authentication.
             IID_IADs,
             (void**)&pTempSchema);
 
    if (SUCCEEDED(hr))
    {
      // Read the fsmoRoleOwner attribute to see which server is the schema master.
      hr = pTempSchema->Get(CComBSTR("fsmoRoleOwner"), &varRole);
      if (SUCCEEDED(hr))
      {
        // fsmoRoleOwner attribute returns the nTDSDSA object.
        // The parent is the server object.
        // Bind to NTDSDSA object and get the parent object.
        wcscpy_s(szPath,L"LDAP://");
        wcscat_s(szPath,varRole.bstrVal);
        hr = ADsOpenObject(szPath,
             NULL,
             NULL,
             ADS_SECURE_AUTHENTICATION, // Use Secure Authentication.
             IID_IADs,
             (void**)&pNTDS);
        if (SUCCEEDED(hr))
        {
          hr = pNTDS->get_Parent(&bstrParent);
          if (SUCCEEDED(hr))
          {
            // Bind to server object
            // and get the reference to the computer object.
            wcscpy_s(szPath,bstrParent);
            hr = ADsOpenObject(szPath,
               NULL,
               NULL,
               ADS_SECURE_AUTHENTICATION, // Use Secure Authentication.
               IID_IADs,
               (void**)&pServer);
            if (SUCCEEDED(hr))
            {
              // Get the dns name of the server.
              hr = pServer->Get(CCOmBSTR("dNSHostName"), &varComputer);
              if (SUCCEEDED(hr))
              {
                *pszSchemaMasterDNSName = (OLECHAR *)CoTaskMemAlloc (sizeof(OLECHAR)*(wcslen(varComputer.bstrVal)+1));
                if (*pszSchemaMasterDNSName)
                {
                  wcscpy_s(*pszSchemaMasterDNSName, varComputer.bstrVal);
                }
                else
                {
                  hr = E_OUTOFMEMORY;
                }
              }
              VariantClear(&varComputer);
            }
            if (pServer)
              pServer->Release();
          }
          SysFreeString(bstrParent);
        }
        if (pNTDS)
          pNTDS->Release();
      }
      VariantClear(&varRole);
    }
    if (pTempSchema)
      pTempSchema->Release();
  }
  VariantClear(&var);
}
if (pObject)
    pObject->Release();
 
return hr;
}