DriverProc İşlevi Oluşturma

Bir DriverProc işlevini, pencere yordamı oluştururken yaptığınız gibi çok benzer bir şekilde oluşturursunuz. İşlev, switch ifadesinden oluşur ve her durum, verilen bir sürücü mesajını işler ve başarı veya başarısızlığı belirten bir değer döndürür. DriverProc işlevi aşağıdaki forma sahiptir:

LONG DriverProc(DWORD dwDriverId, HDRVR hdrvr, UINT msg, 
    LONG lParam1, LONG lParam2)
{
    DWORD dwRes = 0L;

    switch (msg) {
    case DRV_LOAD:
    // Sent when the driver is loaded. This is always   
    // the first message received by a driver. 
        dwRes = 1L;  // returns 0L to fail
        break;

    case DRV_FREE:
    // Sent when the driver is about to be discarded.
    // This is the last message a driver receives
    // before it is freed.
        dwRes = 1L;  // return value ignored
        break;

    case DRV_OPEN:
    // Sent when the driver is opened.
        dwRes = 1L;  // returns 0L to fail
        break;       // value subsequently used
                     // for dwDriverId.

    case DRV_CLOSE:
    // Sent when the driver is closed. Drivers are
    // unloaded when the open count reaches zero.
        dwRes = 1L;  // returns 0L to fail
        break;

    case DRV_ENABLE:
    // Sent when the driver is loaded or reloaded and
    // when Windows is enabled. Install interrupt
    // handlers and initialize hardware. Expect the
    // driver to be in memory only between the enable
    // and disable messages.
        dwRes = 1L;  // return value ignored
        break;

    case DRV_DISABLE:
    // Sent before the driver is freed or when Windows
    // is disabled. Remove interrupt handlers and place
    // hardware in an inactive state.
        dwRes = 1L;  // return value ignored
        break;

    case DRV_INSTALL:
    // Sent when the driver is installed.
        dwRes = DRVCNF_OK;  // Can also return 
        break;              // DRVCNF_CANCEL
                            // and DRV_RESTART

    case DRV_REMOVE:
    // Sent when the driver is removed.
        dwRes = 1L;  // return value ignored
        break;

    case DRV_QUERYCONFIGURE:
    // Sent to determine if the driver can be
    // configured.
        dwRes = 0L;  // Zero indicates configuration
        break;       // NOT supported

    case DRV_CONFIGURE:
    // Sent to display the configuration
    // dialog box for the driver.
        dwRes = DRVCNF_OK;  // Can also return
        break;              // DRVCNF_CANCEL
                            // and DRVCNF_RESTART

    default:
    // Process any other messages.
        return DefDriverProc (dwDriverId, hdrvr, 
            msg, lParam1, lParam2);

    }
    return dwRes;
}