AVCSTRM_CLOSE
The AVCSTRM_CLOSE function code closes the specified stream and frees any resources allocated in AVCSTRM_OPEN.
I/O Status Block
If successful, avcstrm.sys sets Irp->IoStatus.Status to STATUS_SUCCESS.
Possible error return values include:
| Error Status | Description |
|---|---|
| STATUS_DEVICE_REMOVED | The device corresponding to the AVCSTRM_READ operation no longer exists. |
| STATUS_CANCELLED | The request was unable to be completed. |
| STATUS_INVALID_PARAMETER | A parameter specified in the IRP is incorrect, |
| STATUS_INSUFFICIENT_RESOURCES | There were not sufficient system resources to complete the request. |
| STATUS_PENDING | The request has been received but requires further processing. The I/O completion routine will handle the final response. |
AVC_STREAM_REQUEST_BLOCK Input
SizeOfThisBlock, Version and Function
Use the INIT_AVCSTRM_HEADER macro to initialize these members. Pass AVCSTRM_CLOSE in the Request argument of the macro.
AVCStreamContext
Specifies the stream context (handle) of the stream to close. If AVCSTRM_CLOSE returns successfully, this value is no longer valid.
The following is an example of how to specify the stream to close:
pAVCStrmReq = &pStrmExt->AVCStrmReq;
RtlZeroMemory(pAVCStrmReq, sizeof(AVC_STREAM_REQUEST_BLOCK));
INIT_AVCSTRM_HEADER(pAVCStrmReq, AVCSTRM_CLOSE);
pAVCStrmReq->AVCStreamContext = pStrmExt->AVCStreamContext;
Status =
AVCStrmReqSubmitIrpSynch (
pDevExt->pBusDeviceObject,
pStrmExt->pIrpReq,
pAVCStrmReq
);
A subunit driver must first allocate an IRP and an AVC_STREAM_REQUEST_BLOCK structure.
Next, it should use the INIT_AVCSTRM_HEADER macro to initialize the AVC_STREAM_REQUEST_BLOCK structure, passing AVCSTRM_CLOSE as the Request argument to the macro.
Next, the subunit driver sets the AVCStreamContext member to the stream to close.
To send this request, a subunit submits an IRP_MJ_INTERNAL_DEVICE_CONTROL IRP with the IoControlCode member of the IRP set to IOCTL_AVCSTRM_CLASS and the Argument1 member of the IRP set to the AVC_STREAM_REQUEST_BLOCK structure that describes the close operation to take place.
A subunit driver can expect this command to complete synchronously. The result returns immediately without pending operation in avcstrm.sys.
This function code must be called at IRQL = PASSIVE_LEVEL.
Comments
This function uses the AVCStreamContext member of the CommandData union in the AVC_STREAM_REQUEST_BLOCK structure as shown below.
typedef struct _AVC_STREAM_REQUEST_BLOCK {
ULONG SizeOfThisBlock;
ULONG Version;
AVCSTRM_FUNCTION Function;
.
.
PVOID AVCStreamContext;
.
.
} AVC_STREAM_REQUEST_BLOCK, *PAVC_STREAM_REQUEST_BLOCK;
Requirements
Headers: Declared in avcstrm.h. Include avcstrm.h.