WdfDmaTransactionGetRequest function (wdfdmatransaction.h)

Article
04/18/2022

[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

[in] DmaTransaction

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

Requirement	Value
Target Platform	Universal
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(kmdf), KmdfIrql(kmdf), KmdfIrql2(kmdf), KmdfIrqlExplicit(kmdf)