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NdisQueryBufferOffset

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This function retrieves the base virtual address of the range specified in a specified buffer descriptor.

VOID NdisQueryBufferOffset(
IN PNDIS_BUFFER Buffer, 
OUT PUINT Offset, 
OUT PUINT Length );

Parameters

  • Buffer
    Pointer to the buffer descriptor.
  • Offset
    Pointer to a caller-supplied variable in which this function returns the 0-based byte offset within the physical page containing the buffer.
  • Length
    Pointer to a caller-supplied variable in which this function returns the size, in bytes, of the given buffer.

Remarks

This function returns the offset within a physical page at which a given buffer begins. Usually, the buffer descriptor is part of a packet chain.

This function runs faster than the NdisQueryBuffer function. NDIS drivers call this function in situations in which they need to constrain packets by certain criteria. For example, this function can be used to determine if a buffer crosses a page boundary, if it is odd-byte aligned, and so on.

A driver that calls this function runs at IRQL <= DISPATCH_LEVEL.

Requirements

Runs on Versions Defined in Include Link to
Windows CE OS 2.0 and later Ndis.h    

Note   This API is part of the complete Windows CE OS package as provided by Microsoft. The functionality of a particular platform is determined by the original equipment manufacturer (OEM) and some devices may not support this API.

See Also

NdisAllocateBuffer, NdisQueryBuffer, NdisUnchainBufferAtBack, NdisUnchainBufferAtFront

 Last updated on Tuesday, July 13, 2004

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