ReadDmaCounter routine

The ReadDmaCounter routine returns the number of bytes remaining to be transferred during the current subordinate DMA operation.

Syntax


ULONG ReadDmaCounter(
  _In_ PDMA_ADAPTER DmaAdapter
);

Parameters

DmaAdapter [in]

Pointer to the adapter object previously returned by IoGetDmaAdapter representing the system DMA controller channel currently in use.

Return value

ReadDmaCounter returns the number of bytes remaining to be transferred in the current DMA operation.

Remarks

ReadDmaCounter is not a system routine that can be called directly by name. This routine is callable only by pointer from the address returned in a DMA_OPERATIONS structure. Drivers obtain the address of this routine by calling IoGetDmaAdapter.

ReadDmaCounter can be called only by drivers of subordinate DMA devices. Usually, the caller is the driver of a subordinate device that uses a system DMA controller's autoinitialize mode.

Requirements

Target platform

Desktop

Version

Available starting with Windows 2000.

Header

Wdm.h (include Wdm.h, Ntddk.h, or Ntifs.h)

IRQL

<= DISPATCH_LEVEL

DDI compliance rules

IrqlDispatch

See also

DMA_ADAPTER
AllocateCommonBuffer
IoGetDmaAdapter
FlushAdapterBuffers
MapTransfer

 

 

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