NdisAllocateNetBufferListContext function (ndis/nblapi.h)

Call the NdisAllocateNetBufferListContext function to allocate more context space in the NET_BUFFER_LIST_CONTEXT structure of a

NET_BUFFER_LIST structure.


  [in] NET_BUFFER_LIST *NetBufferList,
  [in] USHORT          ContextSize,
  [in] USHORT          ContextBackFill,
  [in] ULONG           PoolTag


[in] NetBufferList

A pointer to a previously allocated NET_BUFFER_LIST structure.

[in] ContextSize

The amount of context space to allocate in the NET_BUFFER_LIST_CONTEXT structure. This amount must be a multiple of the value defined by MEMORY_ALLOCATION_ALIGNMENT.

[in] ContextBackFill

The amount of memory, in addition to the value of ContextSize, to allocate if NDIS must allocate memory to satisfy the request. This amount must be a multiple of the value defined by MEMORY_ALLOCATION_ALIGNMENT.

[in] PoolTag

A kernel pool tag that NDIS uses to allocate the memory for the NET_BUFFER_LIST_CONTEXT structure, if allocation is required. The tag is a string, delimited by single quotation marks, with up to four characters, usually specified in reversed order. The kernel pool tag helps NDIS to identify the owner of the memory.

Return value

NdisAllocateNetBufferListContext returns one of the following:

Return code Description
NdisAllocateNetBufferListContext successfully allocated context space either by reducing the value of the Offset member of the NET_BUFFER_LIST_CONTEXT structure or by allocating new memory.
NdisAllocateNetBufferListContext failed due to insufficient resources.
NdisAllocateNetBufferListContext failed for reasons other than insufficient resources.


If there is enough unused context space available in the NET_BUFFER_LIST_CONTEXT structure to satisfy the request, NdisAllocateNetBufferListContext simply reduces the value of the Offset member in the NET_BUFFER_LIST_CONTEXT structure. Otherwise, NDIS allocates new memory for context space. You can specify ContextBackFill to allocate extra memory so that the next call to NdisAllocateNetBufferListContext does not have to allocate memory.

Call the NdisFreeNetBufferListContext function to release the context space in the NET_BUFFER_LIST_CONTEXT structure that was allocated with NdisAllocateNetBufferListContext.


Minimum supported client Supported in NDIS 6.0 and later.
Target Platform Universal
Header ndis/nblapi.h (include ndis.h)
Library Ndis.lib
DDI compliance rules Irql_NetBuffer_Function(ndis)

See also