Writing Performance Data to a Log File - c++

Question

I'm trying to use one of the windows examples to have some CPU data. When I try to debug the below code I receive the message "The command line must include a valid log file name" I am using MS Visual studio 2013 and I am intrested in Total Processor time%.
Pls advise.
More details about the code:
http://msdn.microsoft.com/en-us/library/windows/desktop/aa373228(v=vs.85).aspx
The Code:
#include <windows.h>
#include <stdio.h>
#include <pdh.h>
#include <pdhmsg.h>
#pragma comment(lib, "pdh.lib")
CONST PWSTR COUNTER_PATH = L"\\Processor(0)\\% Processor Time";
CONST ULONG SAMPLE_INTERVAL_MS = 1000;
void DisplayCommandLineHelp(void)
{
wprintf(L"The command line must include a valid log file name.\n");
}
void wmain(int argc, WCHAR **argv)
{
HQUERY hQuery = NULL;
HLOG hLog = NULL;
PDH_STATUS pdhStatus;
DWORD dwLogType = PDH_LOG_TYPE_CSV;
HCOUNTER hCounter;
DWORD dwCount;
if (argc != 2)
{
DisplayCommandLineHelp();
goto cleanup;
}
// Open a query object.
pdhStatus = PdhOpenQuery(NULL, 0, &hQuery);
if (pdhStatus != ERROR_SUCCESS)
{
wprintf(L"PdhOpenQuery failed with 0x%x\n", pdhStatus);
goto cleanup;
}
// Add one counter that will provide the data.
pdhStatus = PdhAddCounter(hQuery,
COUNTER_PATH,
0,
&hCounter);
if (pdhStatus != ERROR_SUCCESS)
{
wprintf(L"PdhAddCounter failed with 0x%x\n", pdhStatus);
goto cleanup;
}
// Open the log file for write access.
pdhStatus = PdhOpenLog(argv[1],
PDH_LOG_WRITE_ACCESS | PDH_LOG_CREATE_ALWAYS,
&dwLogType,
hQuery,
0,
NULL,
&hLog);
if (pdhStatus != ERROR_SUCCESS)
{
wprintf(L"PdhOpenLog failed with 0x%x\n", pdhStatus);
goto cleanup;
}
// Write 10 records to the log file.
for (dwCount = 0; dwCount < 10; dwCount++)
{
wprintf(L"Writing record %d\n", dwCount);
pdhStatus = PdhUpdateLog(hLog, NULL);
if (ERROR_SUCCESS != pdhStatus)
{
wprintf(L"PdhUpdateLog failed with 0x%x\n", pdhStatus);
goto cleanup;
}
// Wait one second between samples for a counter update.
Sleep(SAMPLE_INTERVAL_MS);
}
cleanup:
// Close the log file.
if (hLog)
PdhCloseLog(hLog, 0);
// Close the query object.
if (hQuery)
PdhCloseQuery(hQuery);
}

Answer 1

if (argc != 2)
{
DisplayCommandLineHelp();
goto cleanup;
}
This is your answer right here. You need to set your project up to pass a filename to the program when it runs.
argc counts how many command-line arguments your program has received. It always gets at least one, the name of the program itself. But this program needs a second one, the name of the logfile to write to.