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AVCSTRM_CLOSE

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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 If AVCSTRM_CLOSE returns successfully, this value is no longer valid.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.

See Also

AVC_STREAM_REQUEST_BLOCK

INIT_AVCSTRM_HEADER

IRP_MJ_INTERNAL_DEVICE_CONTROL

IOCTL_AVCSTRM_CLASS

AVCSTRM_FUNCTION