Hi Weiji, I tried “IoRegisterDeviceInterface()” with MSVAD. Its not working for me. The following method will help you. In DriverEntry First call PcInitializeAdapterDriver Then assign your dispatch routines In AddDevice IoCreateDevice IoCreateSymbolicLink In Application Open the handle by CreateFile() Regards Vargheese _____ From: wdmaudiodev-bounce@xxxxxxxxxxxxx [mailto:wdmaudiodev-bounce@freelists. org] On Behalf Of Weiji Zheng Sent: Thursday, July 20, 2006 10:19 AM To: wdmaudiodev@xxxxxxxxxxxxx Subject: [wdmaudiodev] for help in implementation virtual audio driver Hi I am developing one project, that is, PCM data is transfered into MSVAD by usr mode, and MSVAD then put these PCM data into another application based on DirectSound, such as Skype, that means MSVAD will be open simultaneously both the applications. Actaully, I encounter the same question as following: 1. how can I get the handle of the MSVAD(Simple)? 2. I tried to use IoRegisterDeviceInterface() in AddDevice() of MSVAD(Simple), and then in my user mode application I use SetupDiGetDeviceInterfaceDetail() and CreateFile() to get the handle of the MSVAD device. It seems that I can get the handle of the MSVAD(Simple), but the Graph Edit con not find any device about MSVAD, Do you have any idea about this? Maybe the implementation in IRP_MAJOR_CREATE is one key. //dispatch function extern "C" NTSTATUS PCP_Create ( IN PDEVICE_OBJECT pDeviceObject, IN PIRP pIrp ) { PIO_STACK_LOCATION IrpStack = IoGetCurrentIrpStackLocation(pIrp); //PDEVICE_EXTENSION pDevExt = (PDEVICE_EXTENSION)pDeviceObject->DeviceExtension; NTSTATUS ntStatus = STATUS_SUCCESS; DPF(D_TERSE, ("[enter PCP_Create]")); DbgPrint("the Flags is 0x%x\n", pIrp->Flags); DbgPrint("the RequestorMode is 0x%x\n", pIrp->RequestorMode); if(pIrp->RequestorMode == 0x1) //my own application {// Complete successfully pIrp->IoStatus.Status = STATUS_SUCCESS; pIrp->IoStatus.Information = 0; IoCompleteRequest(pIrp, IO_NO_INCREMENT); return STATUS_SUCCESS; } else //Graph Edit { // // Pass the IRPs on to PortCls // ntStatus = PcDispatchIrp( pDeviceObject, pIrp ); if(NT_SUCCESS(ntStatus)) DbgPrint("success to open device\n"); else DbgPrint("fail to open device\n"); return ntStatus; } } But when I run own application(not Graph Edit), the system crash! so would you please give me some advice. thanks for any help. best regards --weiji zheng _____ <http://cn.mail.yahoo.com/> 雅虎免费邮箱-3.5G容量,20M附件