C / C++ / MFC

The Portmon GUI is responsible for identifying serial and parallel ports. It does so by enumerating the serial ports that are configured under HKEY_LOCAL_MACHINE\Hardware\DeviceMap\SerialComm and the parallel ports defined under HKEY_LOCAL_MACHINE\Hardware\DeviceMap\Parallel Ports. These keys contain the mappings between serial and parallel port device names and the Win32-accessible names. 

When you select a port to monitor, Portmon sends a request to its device driver that includes the NT name (e.g. \device\serial0) that you are interested in. The driver uses standard filtering APIs to attach its own filter device object to the target device object. First, it uses ZwCreateFile to open the target device. Then it translates the handle it receives back from ZwCreateFile to a device object pointer. After creating its own filter device object that matches the characteristics of the target, the driver calls IoAttachDeviceByPointer to establish the filter. From that point on the Portmon driver will see all requests aimed at the target device. A complete source code example of filtering is demonstrated by our Filemon file system monitor.

Portmon has built-in knowledge of all standard serial and parallel port IOCTLs, which are the primary way that applications and drivers configure and read status information from ports. The IOCTLs are defined in the DDK file \ddk\src\comm\inc\ntddser.h and \ddk\src\comm\inc\ntddpar.h, and some are documented in the DDK. 

CMyProgressDialog dlg;
dlg.Create();
// lengthy processing here
for(whatever)
  dlg.UpdateStatus(currentstatus);

void OnMenuItem()
{

hrGlass.SetCursor = 'hourglass';

LengthyOperation();

hrGlass.SetCursor = 'normal'

}

void OnMenuItem()
{  
  CWaitCursor wait;
  LengthyOperation();
}