Navigation des compteurs de performances

L’exemple suivant montre comment appeler PdhBrowseCounters pour parcourir les compteurs de performances. L’exemple montre également comment collecter et mettre en forme des données de compteur brutes pour l’affichage.

#include <windows.h>
#include <stdio.h>
#include <conio.h>
#include <pdh.h>
#include <pdhmsg.h>

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

CONST ULONG SAMPLE_INTERVAL_MS    = 1000;
CONST PWSTR BROWSE_DIALOG_CAPTION = L"Select a counter to monitor.";

void wmain(void)
{
    PDH_STATUS Status;
    HQUERY Query = NULL;
    HCOUNTER Counter;
    PDH_FMT_COUNTERVALUE DisplayValue;
    DWORD CounterType;
    SYSTEMTIME SampleTime;
    PDH_BROWSE_DLG_CONFIG BrowseDlgData;
    WCHAR CounterPathBuffer[PDH_MAX_COUNTER_PATH];

    //
    // Create a query.
    //

    Status = PdhOpenQuery(NULL, NULL, &Query);
    if (Status != ERROR_SUCCESS) 
    {
       wprintf(L"\nPdhOpenQuery failed with status 0x%x.", Status);
       goto Cleanup;
    }

    //
    // Initialize the browser dialog window settings.
    //

    ZeroMemory(&CounterPathBuffer, sizeof(CounterPathBuffer));
    ZeroMemory(&BrowseDlgData, sizeof(PDH_BROWSE_DLG_CONFIG));

    BrowseDlgData.bIncludeInstanceIndex = FALSE;
    BrowseDlgData.bSingleCounterPerAdd = TRUE;
    BrowseDlgData.bSingleCounterPerDialog = TRUE;
    BrowseDlgData.bLocalCountersOnly = FALSE;
    BrowseDlgData.bWildCardInstances = TRUE;
    BrowseDlgData.bHideDetailBox = TRUE;
    BrowseDlgData.bInitializePath = FALSE;
    BrowseDlgData.bDisableMachineSelection = FALSE;
    BrowseDlgData.bIncludeCostlyObjects = FALSE;
    BrowseDlgData.bShowObjectBrowser = FALSE;
    BrowseDlgData.hWndOwner = NULL;
    BrowseDlgData.szReturnPathBuffer = CounterPathBuffer;
    BrowseDlgData.cchReturnPathLength = PDH_MAX_COUNTER_PATH;
    BrowseDlgData.pCallBack = NULL;
    BrowseDlgData.dwCallBackArg = 0;
    BrowseDlgData.CallBackStatus = ERROR_SUCCESS;
    BrowseDlgData.dwDefaultDetailLevel = PERF_DETAIL_WIZARD;
    BrowseDlgData.szDialogBoxCaption = BROWSE_DIALOG_CAPTION;

    //
    // Display the counter browser window. The dialog is configured
    // to return a single selection from the counter list.
    //

    Status = PdhBrowseCounters(&BrowseDlgData);

    if (Status != ERROR_SUCCESS) 
    {
        if (Status == PDH_DIALOG_CANCELLED) 
        {
            wprintf(L"\nDialog canceled by user.");
        }
        else 
        {
            wprintf(L"\nPdhBrowseCounters failed with status 0x%x.", Status);
        }
        goto Cleanup;
    } 
    else if (wcslen(CounterPathBuffer) == 0) 
    {
        wprintf(L"\nUser did not select any counter.");
        goto Cleanup;
    }
    else
    {
        wprintf(L"\nCounter selected: %s\n", CounterPathBuffer);
    }

    //
    // Add the selected counter to the query.
    //

    Status = PdhAddCounter(Query, CounterPathBuffer, 0, &Counter);
    if (Status != ERROR_SUCCESS) 
    {
        wprintf(L"\nPdhAddCounter failed with status 0x%x.", Status);
        goto Cleanup;
    }

    //
    // Most counters require two sample values to display a formatted value.
    // PDH stores the current sample value and the previously collected
    // sample value. This call retrieves the first value that will be used
    // by PdhGetFormattedCounterValue in the first iteration of the loop
    // Note that this value is lost if the counter does not require two
    // values to compute a displayable value.
    //

    Status = PdhCollectQueryData(Query);
    if (Status != ERROR_SUCCESS) 
    {
        wprintf(L"\nPdhCollectQueryData failed with 0x%x.\n", Status);
        goto Cleanup;
    }

    //
    // Print counter values until a key is pressed.
    //

    while (!_kbhit()) 
    {
        Sleep(SAMPLE_INTERVAL_MS);

        GetLocalTime(&SampleTime);

        Status = PdhCollectQueryData(Query);
        if (Status != ERROR_SUCCESS) 
        {
            wprintf(L"\nPdhCollectQueryData failed with status 0x%x.", Status);
        }

        wprintf(L"\n\"%2.2d/%2.2d/%4.4d %2.2d:%2.2d:%2.2d.%3.3d\"",
                SampleTime.wMonth,
                SampleTime.wDay,
                SampleTime.wYear,
                SampleTime.wHour,
                SampleTime.wMinute,
                SampleTime.wSecond,
                SampleTime.wMilliseconds);

        //
        // Compute a displayable value for the counter.
        //

        Status = PdhGetFormattedCounterValue(Counter,
                                             PDH_FMT_DOUBLE,
                                             &CounterType,
                                             &DisplayValue);
        if (Status != ERROR_SUCCESS) 
        {
            wprintf(L"\nPdhGetFormattedCounterValue failed with status 0x%x.", Status);
            goto Cleanup;
        }

        wprintf(L",\"%.20g\"", DisplayValue.doubleValue);
    }

Cleanup:

    //
    // Close the query.
    //

    if (Query) 
    {
       PdhCloseQuery(Query);
    }
}