NdisGroupActiveProcessorCount function

The NdisGroupActiveProcessorCount function returns the number of processors that are currently active in a specified group.


ULONG NdisGroupActiveProcessorCount(
  USHORT Group



A USHORT value that identifies a processor group in the local computer system.

Return Value

NdisGroupActiveProcessorCount returns a ULONG value for the number of processors that are active in the group that is specified in the Group parameter. The number of processors is a zero-based value.

If the Group parameter is ALL_PROCESSOR_GROUPS, NdisGroupActiveProcessorCount returns the number of active processors in the local computer.


An NDIS driver might call the NdisGroupActiveProcessorCount function during initialization before it allocates resources.

The processor count that NdisGroupActiveProcessorMask returns can change at runtime on SKUs that support hot-add functionality for CPUs.

Note  NDIS drivers should not use the NdisSystemProcessorCount function to retrieve the number of processors that are currently active. Also, NDIS 6.20 drivers should not use the NdisSystemActiveProcessorCount function because it only returns the processor count and provides the affinity mask as an out parameter, for processor group 0.
To obtain an active affinity mask, call the NdisGroupActiveProcessorMask function.

To obtain the maximum number of processors in a group, call the NdisGroupMaxProcessorCount function.


Minimum supported client Supported in NDIS 6.20 and later.
Target Platform Universal
Header ndis.h (include Ndis.h)
Library Ndis.lib
IRQL Any level

See Also