WdfDmaTransactionGetRequest function (wdfdmatransaction.h)
[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) |