FwpsPendClassify0 function (fwpsk.h)

A callout's classifyFn function calls FwpsPendClassify0 to pend the current classify request. After the request is pended, the callout driver must complete the processing of the classify request asynchronously by calling FwpsCompleteClassify0.

Note  FwpsPendClassify0 is a specific version of FwpsPendClassify. See WFP Version-Independent Names and Targeting Specific Versions of Windows for more information.


NTSTATUS FwpsPendClassify0(
  UINT64             classifyHandle,
  UINT64             filterId,
  UINT32             flags,
  FWPS_CLASSIFY_OUT0 *classifyOut



[in] The classification handle that identifies the callout driver's processing at the current layer. This handle is obtained by calling FwpsAcquireClassifyHandle0.


[in] The value of the FilterId member of the classifyFn function's filter parameter. For more information about the FilterId member, see FWPS_FILTER1.


[in] Reserved for future use. Set to zero.


[in, out] Set to the classifyOut parameter of the callout driver's classifyFn function. The classifyOut parameter of classifyFn is listed as an output parameter in the header, but it contains enough information on input to be useful to the engine when passed to FwpsPendClassify.

Return value

The FwpsPendClassify0 function returns one of the following NTSTATUS codes.

Return code Description
The classify request was successfully pended.
The engine does not allow asynchronous classification at the layer from which the call was made.
Other status codes
An error occurred.


FwpsPendClassify0 puts the classification of the indicated event in a pended state. A callout driver typically pends classification so that more processing can be done outside the scope of the classifyFn callout function. The callout driver can then pass the classification handle and any other pertinent data about the indication to a function with less impact on performance than the driver callout functions. When processing is complete, the callout must call FwpsCompleteClassify0 to remove the pended state. At the time of the call to FwpsCompleteClassify, the callout driver must return a filled-out FWPS_CLASSIFY_OUT0 structure just as it would in an inline classification.

FwpsPendClassify0 increments the reference count for the classification handle passed in the classifyHandle parameter. After the callout driver calls this function, it can call FwpsReleaseClassifyHandle0 to release the local instance. When FwpsCompleteClassify0 is called, the reference to the handle will be decremented automatically.


Minimum supported client Available starting with Windows 7.
Target Platform Universal
Header fwpsk.h (include Fwpsk.h)
Library Fwpkclnt.lib

See also