NDIS_BUFFER_TO_SPAN_PAGES (Windows CE 5.0)

项目
09/14/2012

This macro determines how many physical pages of memory are being used to back a specified buffer.

ULONG NDIS_BUFFER_TO_SPAN_PAGES(PNDIS_BUFFER _Buffer);

Parameters

_Buffer
Specifies the buffer descriptor mapping the buffer.

Return Values

The return value is the Windows CE version, which is always 1.

Remarks

This macro is used by DMA drivers to determine how many physical discontiguities exist in a specified virtual buffer.

The NDIS_BUFFER_TO_SPAN_PAGES macro is defined as follows.

#define NDIS_BUFFER_TO_SPAN_PAGES(_Buffer)                  \
    (MmGetMdlByteCount(_Buffer)==0 ?                        \
                1 :                                         \
                (COMPUTE_PAGES_SPANNED(                     \
                        MmGetMdlVirtualAddress(_Buffer),    \
                        MmGetMdlByteCount(_Buffer))))

Requirements

OS Versions: Windows CE .NET 4.0 and later.
Header: Ndis.h.

See Also

NDIS_BUFFER | NdisAllocateBuffer | NdisFreeBuffer | NdisBufferVirtualAddress | Subordinate DMA Network Adapters

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