How to get the CPU Usage of other applications? Thanks

From:

linuxfedora@yahoo.com.hk

Newsgroups:

comp.lang.c++

Date:

Mon, 14 Jul 2008 18:21:44 -0700 (PDT)

Message-ID:

<9157be20-f83f-446f-959e-932a660f6b4a@k37g2000hsf.googlegroups.com>

Language: C++, tool: Borland C++ Builder 4.0

I have tried to search in the Internet, and found that i can use WMI,
here is an example from Internet:
  private void timer1_Tick(object sender, System.EventArgs e)
  {
   ManagementObjectSearcher search = new
ManagementObjectSearcher("Select * from
Win32_PerfRawData_PerfOS_Processor where Name='0' ");
   foreach(ManagementObject info in search.Get())
   {
    decimal PercentProcessorTime=0;
    ulong u_newCPU = (ulong)info["PercentProcessorTime"];
    ulong u_newNano = (ulong)info["TimeStamp_Sys100NS"];
    decimal d_newCPU = Convert.ToDecimal(u_newCPU);
    decimal d_newNano = Convert.ToDecimal(u_newNano);
    decimal d_oldCPU = Convert.ToDecimal(u_oldCPU);
    decimal d_oldNano = Convert.ToDecimal(u_oldNano);

    PercentProcessorTime =
     (1 - ((d_newCPU-d_oldCPU)/(d_newNano - d_oldNano)))*100m;

    u_oldCPU = u_newCPU;
    u_oldNano = u_newNano;

    this.Text = PercentProcessorTime.ToString("N"); //=CF=D4=CA=BE=B5=BD=
=B4=B0=CC=E5=B1=EA=CC=E2=C0=B8
   }
  }

but i am writing Borland C++ Builder program, so i wrote:

GetWmiInfo(Memo1->Lines, "select * from
win32_PerfFormattedData_PerfProc_Process where name = 'explorer");

void GetWmiInfo(TStrings *lpList, WideString wsClass)
{

  IWbemLocator *pWbemLocator = NULL;
  if(CoCreateInstance(CLSID_WbemAdministrativeLocator, NULL,
CLSCTX_INPROC_SERVER|CLSCTX_LOCAL_SERVER, IID_IUnknown,
(void**)&pWbemLocator) == S_OK)
   {
     IWbemServices *pWbemServices = NULL;
     WideString wsNamespace = (L"root\\cimv2");
     if(pWbemLocator->ConnectServer(wsNamespace, NULL, NULL, NULL, 0,
NULL, NULL, &pWbemServices) == S_OK)
      {
        IEnumWbemClassObject *pEnumClassObject = NULL;
        WideString wsWQL=L"WQL", wsQuery= wsClass;//
WideString(L"Select * from ")+wsClass;
        if(pWbemServices->ExecQuery(wsWQL, wsQuery,
WBEM_FLAG_RETURN_IMMEDIATELY,NULL, &pEnumClassObject) == S_OK)
         {
           IWbemClassObject *pClassObject = NULL;
           ULONG uCount = 1, uReturned;
           if(pEnumClassObject->Reset() == S_OK)
            {
              int iEnumIdx = 0;
              while(pEnumClassObject->Next(WBEM_INFINITE, uCount,
&pClassObject, &uReturned) == S_OK)
               {
                 lpList->Add("---------------- ["+IntToStr(iEnumIdx)
+"] -----------------");

                 SAFEARRAY *pvNames = NULL;
                 if(pClassObject->GetNames(NULL, WBEM_FLAG_ALWAYS |
WBEM_MASK_CONDITION_ORIGIN, NULL, &pvNames) == S_OK)
                  {
                    long vbl, vbu;
                    SafeArrayGetLBound(pvNames, 1, &vbl);
                    SafeArrayGetUBound(pvNames, 1, &vbu);
                    for(long idx=vbl; idx<=vbu; idx++)
                    {
                       long aidx = idx;
                       wchar_t *wsName = 0;
                       VARIANT vValue;
                       VariantInit(&vValue);
                       SafeArrayGetElement(pvNames, &aidx, &wsName);

                       BSTR bs = SysAllocString(wsName);
                       HRESULT hRes = pClassObject->Get(bs, 0,
&vValue, NULL, 0);
                       SysFreeString(bs);

                       if(hRes == S_OK)
                       {
                          AnsiString s;
                          Variant v = *(Variant*)&vValue;
                          if(v.IsArray())
                          {
                             for(int i=v.ArrayLowBound();
i<=v.ArrayHighBound(); i++)
                              {
                                Variant a = v.GetElement(i);
                                if(!s.IsEmpty())
                                  s+=", ";
                                s+=VarToStr(a);
                              }
                           }
                          else
                           {
                             s = VarToStr(v);
                           }
                          lpList->Add(AnsiString(wsName)+"="+s);
                        }

                       VariantClear(&vValue);
                       SysFreeString(wsName);
                     }
                  }
                 if(pvNames)SafeArrayDestroy(pvNames);
                 iEnumIdx++;
               }
            }
           if(pClassObject)pClassObject->Release();
         }
        if(pEnumClassObject)pEnumClassObject->Release();
      }
     if(pWbemServices)pWbemServices->Release();
   }
  if(pWbemLocator)pWbemLocator->Release();
}

But i found that the value TimeStamp_Sys100NS i get is NULL, so i
cannot make a calculation like the example one, can anyone tell me why?
Thanks!!