Thread: How do you access information from win32_operatingsystem class?

Code:

#include <iostream>
#include <iomanip>
using namespace std;

#ifndef _WIN32_DCOM
#   define _WIN32_DCOM
#endif
#ifndef UNICODE
#   define UNICODE
#endif
#include <Windows.h>

#include <comdef.h>
#include <comutil.h>

#include <Wbemidl.h>
#pragma comment(lib, "wbemuuid.lib")

_COM_SMARTPTR_TYPEDEF(IWbemLocator, __uuidof(IWbemLocator));
_COM_SMARTPTR_TYPEDEF(IWbemServices, __uuidof(IWbemServices));
_COM_SMARTPTR_TYPEDEF(IEnumWbemClassObject, __uuidof(IEnumWbemClassObject));
_COM_SMARTPTR_TYPEDEF(IWbemClassObject, __uuidof(IWbemClassObject));

//------------------------------------------------------------------------------

inline void TESTHR(HRESULT hr) 
{ 
    if (FAILED(hr))
        _com_issue_error(hr);
}//TESTHR

//------------------------------------------------------------------------------

void GetProperty(IWbemClassObjectPtr &obj, const wchar_t *prop_name, 
                 _variant_t &prop_val)
{
    CIMTYPE cim_type;
    TESTHR(obj->Get(prop_name, 0, &prop_val, &cim_type, 0));
}//GetProperty

//------------------------------------------------------------------------------

void PrintProperty(IWbemClassObjectPtr &obj, const wchar_t *prop_name)
{
    _variant_t prop_val;
    GetProperty(obj, prop_name, prop_val);

    wcout << prop_name << L" = ";
    if (prop_val.vt == VT_NULL)
        wcout  << L"NULL" << endl;
    else
    {
        bool bExcept = false;
        try
        {
            wcout << (const wchar_t*)(_bstr_t)prop_val << endl;
        }//try
        catch (_com_error&) {bExcept = true;}
        
        if (!wcout)
            wcout.clear();
        if (bExcept)
            wcout << L"{failed to convert variant of type " 
                  << prop_val.vt << L"}" << endl;
    }//else
}//PrintProperty

//------------------------------------------------------------------------------

void print_OS_info()
{
    try
    {
        IWbemLocatorPtr pLoc;
        TESTHR(CoCreateInstance(CLSID_WbemLocator, 0, CLSCTX_INPROC_SERVER, 
                                IID_IWbemLocator, (void**)&pLoc));
        
        IWbemServicesPtr pSvc;
        TESTHR(pLoc->ConnectServer(_bstr_t(L"ROOT\\CIMV2"), 
                                   0, 0, 0, 0, 0, 0, &pSvc));

        TESTHR(CoSetProxyBlanket(pSvc, RPC_C_AUTHN_WINNT, RPC_C_AUTHZ_NONE, 0,
                                 RPC_C_AUTHN_LEVEL_CALL, 
                                 RPC_C_IMP_LEVEL_IMPERSONATE, 0,EOAC_NONE));

        IEnumWbemClassObjectPtr pObjEnum;
        const long flags = WBEM_FLAG_FORWARD_ONLY | 
                           WBEM_FLAG_RETURN_IMMEDIATELY;
        TESTHR(pSvc->ExecQuery(_bstr_t("WQL"), 
                               _bstr_t("SELECT * FROM Win32_OperatingSystem"),
                               flags, 0, &pObjEnum));

        IWbemClassObjectPtr pOS;
        ULONG returned = 0;
        for (;;)
        {
            TESTHR(pObjEnum->Next(WBEM_INFINITE, 1, &pOS, &returned));
            if (!returned)
                break;

            PrintProperty(pOS, L"Caption");
            PrintProperty(pOS, L"Version");
            PrintProperty(pOS, L"Codeset");
            PrintProperty(pOS, L"CSDVersion");
            PrintProperty(pOS, L"CSName");
            PrintProperty(pOS, L"TotalVisibleMemorySize");
         }//for
    }//try
    catch (_com_error &err)
    {
        cerr << "COM error : " << hex << setw(8) << err.Error() << endl;
        _bstr_t bstrSrc = err.Source();
        wchar_t *src = (wchar_t*)bstrSrc;
        if (src)
            wcout << L", src=[" << src << L"]" << endl;
            
        _bstr_t bstrDesc = err.Description();
        wchar_t *desc = (wchar_t*)bstrDesc;
        if (desc)
            wcout << L", desc=[" << desc << L"]" << endl;

        const wchar_t *errmsg = err.ErrorMessage();
        if (errmsg)
        {
            wcout << L", msg=[" << errmsg << L"]" << endl;
            LocalFree((HLOCAL)errmsg);
        }//if
    }//catch
}//print_PhysicalMedia_info

//------------------------------------------------------------------------------

int main()
{
    CoInitializeEx(0, COINIT_MULTITHREADED);
    TESTHR(CoInitializeSecurity(0, -1, 0, 0, RPC_C_AUTHN_LEVEL_DEFAULT,
                                RPC_C_IMP_LEVEL_IMPERSONATE, 0, 
                                EOAC_NONE, 0));

    print_OS_info();

    CoUninitialize();
    return 0;
}//main

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