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WdfDmaTransactionGetRequest method

[Applies to KMDF only]

The WdfDmaTransactionGetRequest method retrieves a handle to the framework request object that is associated with a specified DMA transaction.

Syntax


WDFREQUEST WdfDmaTransactionGetRequest(
  [in]  WDFDMATRANSACTION DmaTransaction
);

Parameters

DmaTransaction [in]

A handle to a DMA transaction object that the driver obtained from a previous call to WdfDmaTransactionCreate.

Return value

WdfDmaTransactionGetRequest returns a handle to the framework request object that is associated with the DMA transaction that the DmaTransaction parameter specified.

A bug check occurs if the driver supplies an invalid object handle.

Remarks

A driver can call WdfDmaTransactionGetRequest only for DMA transactions that the driver created by calling WdfDmaTransactionInitializeUsingRequest. If a driver calls WdfDmaTransactionGetRequest for a DMA transaction that it created by calling WdfDmaTransactionInitialize, WdfDmaTransactionGetRequest returns NULL.

For more information about completing DMA transfers, see Completing a DMA Transfer.

Examples

The following code example obtains a handle to the framework request object that is associated with a specified DMA transaction.


WDFREQUEST  request;

request = WdfDmaTransactionGetRequest(dmaTransaction);

Requirements

Minimum KMDF version

1.0

Header

Wdfdmatransaction.h (include Wdf.h)

Library

Wdf01000.sys (see Framework Library Versioning.)

IRQL

<=DISPATCH_LEVEL

DDI compliance rules

DriverCreate, KmdfIrql, KmdfIrql2

See also

WdfDmaTransactionCreate
WdfDmaTransactionInitialize
WdfDmaTransactionInitializeUsingRequest

 

 

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