WMI Query Help

[mbaranski]

I've got the following code, that does not work. I get an invalid query error, does anyone know why?

Thanks,
M.

#define _WIN32_DCOM
#include <iostream>
using namespace std;
#include <comdef.h>
#include <Wbemidl.h>

# pragma comment(lib, "wbemuuid.lib")

int main(int argc, char **argv)
{
HRESULT hres;
VARIANT v;

// Initialize COM.
hres = CoInitializeEx(0, COINIT_MULTITHREADED);
if (FAILED(hres))
{
cout << "Failed to 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 to initialize security. "
<< "Error code = 0x"
<< hex << hres << endl;
CoUninitialize();
return 1; // Program has failed.
}

// Obtain the initial locator to Windows Management
// on a particular host computer.
IWbemLocator *pLoc = 0;

hres = CoCreateInstance(
CLSID_WbemLocator,
0,
CLSCTX_INPROC_SERVER,
IID_IWbemLocator, (LPVOID *) &pLoc);

if (FAILED(hres))
{
cout << "Failed to create IWbemLocator object. "
<< "Error code = 0x"
<< hex << hres << endl;
CoUninitialize();
return 1; // Program has failed.
}

IWbemServices *pSvc = 0;

// Connect to the root\cimv2 namespace with the
// current user and obtain pointer pSvc
// to 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 to ROOT\\CIMV2 WMI namespace" << endl;

// Set the IWbemServices proxy so that impersonation
// of the user (client) occurs.
hres = CoSetProxyBlanket(

pSvc, // the proxy to 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 the IWbemServices pointer to make requests of WMI.
// Make requests here:

// For example, query for print queues that
// have more than 10 jobs
IEnumWbemClassObject* pEnumerator = NULL;
hres = pSvc->ExecQuery(
bstr_t("WQL"),
bstr_t("SELECT * Win32_UserAccount"),
//"Where Name <> '_Total'"),
WBEM_FLAG_FORWARD_ONLY | WBEM_FLAG_RETURN_IMMEDIATELY,
NULL,
&pEnumerator);

if (FAILED(hres))
{
cout << "Query for print queues failed. "
<< "Error code = 0x"
<< hex << hres << endl;
pSvc->Release();
pLoc->Release();
CoUninitialize();
return 1; // Program has failed.
}
else
{
do
{
IWbemClassObject* pInstance = NULL;
ULONG dwCount = NULL;

hres = pEnumerator->Next(
WBEM_INFINITE,
1,
&pInstance,
&dwCount);

if(SUCCEEDED (hres))
{
cout << "Looping, got [" << dwCount << "] instance(s), pointer is [" << pInstance << "]" << endl;
BSTR strClassProp = SysAllocString(L"__CLASS");
hres = pInstance->Get(strClassProp, 0, &v, 0, 0);
SysFreeString(strClassProp);

// check the HRESULT to see if the action succeeded.

if (SUCCEEDED(hres) && (V_VT(&v) == VT_BSTR))
{
wprintf(L"The class name is %s\n.", V_BSTR(&v));
}
else
{
wprintf(L"Error in getting specified object\n");
return 1;
}
}
else
{
IErrorInfo *eInfo;
GetErrorInfo(0, &eInfo);
BSTR bSTRErrDesc = SysAllocString(L"__CLASS");;
eInfo->GetHelpFile(&bSTRErrDesc);
cout << "Error with fetch: [" << hres << "]" << "[" << bSTRErrDesc << "]" << endl;
return 1;
}
VariantClear(&v);
} while (hres == WBEM_S_NO_ERROR);
}

// Cleanup
// ========

pSvc->Release();
pLoc->Release();
CoUninitialize();

return 0; // Program successfully completed.
}

 

[mbaranski]

OK, DUH, the select syntax is wrong.

It should be:

bstr_t("SELECT * FROM Win32_UserAccount")

and it works fine.