NdisMapFile function (ndis.h)

The NdisMapFile function maps an already open file into a caller-accessible buffer if the file is currently unmapped.

Syntax

void NdisMapFile(
  [out] PNDIS_STATUS Status,
  [out] PVOID        *MappedBuffer,
  [in]  NDIS_HANDLE  FileHandle
);

Parameters

[out] Status

A pointer to a caller-supplied variable in which this function returns the status of the mapping operation, which can be one of the following:

NDIS_STATUS_SUCCESS

The caller has exclusive access to the file contents until the NdisUnmapFile function is called.

NDIS_STATUS_ALREADY_MAPPED

The caller cannot access the file contents at this time.

[out] MappedBuffer

A pointer to a caller-supplied variable in which this function returns the base virtual address of the mapped file contents or NULL.

[in] FileHandle

The handle that was returned by a preceding call to the NdisOpenFile function.

Return value

None

Remarks

NdisMapFile associates (maps) a virtual address range with an opened file so the driver can access the file contents. NdisMapFile allows only one mapping of a particular file to be outstanding at any time. Consequently, a successful caller is given exclusive access to the file data until NdisUnmapFile or the NdisCloseFile function is called.

A miniport driver can map and unmap such an open file as necessary, using alternating calls to NdisMapFile and NdisUnmapFile. A call to NdisCloseFile releases the FileHandle and deallocates the buffer containing the file contents.

A miniport driver can call NdisMapFile only during initialization.

Requirements

See also

MiniportInitializeEx

NdisCloseFile

NdisOpenFile

NdisUnmapFile