PIBIO_ENGINE_QUERY_INDEX_VECTOR_SIZE_FN callback function (winbio_adapter.h)
Called by the Windows Biometric Framework to retrieve the size of the index vector used by the engine adapter.
Syntax
PIBIO_ENGINE_QUERY_INDEX_VECTOR_SIZE_FN PibioEngineQueryIndexVectorSizeFn;
HRESULT PibioEngineQueryIndexVectorSizeFn(
[in, out] PWINBIO_PIPELINE Pipeline,
[out] PSIZE_T IndexElementCount
)
{...}
Parameters
[in, out] Pipeline
Pointer to a WINBIO_PIPELINE structure associated with the biometric unit performing the operation.
[out] IndexElementCount
Address of a variable that receives the number of array elements in the index vector.
Return value
If the function succeeds, it returns S_OK. If the function fails, it must return one of the following HRESULT values to indicate the error.
Return code | Description |
---|---|
|
A mandatory pointer parameter is NULL. |
Remarks
The index vector is used by the engine adapter to index the available biometric templates.
Examples
The following pseudocode shows one possible implementation of this function. The example does not compile. You must adapt it to suit your purpose.
///////////////////////////////////////////////////////////////////////////////
//
// EngineAdapterQueryIndexVectorSize
//
// Purpose:
// Called by the Windows Biometric Framework to retrieve the size of
// the index vector used by the engine adapter.
//
// Parameters:
// Pipeline - Pointer to a WINBIO_PIPELINE structure associated
// with the biometric unit performing the operation.
// IndexElementCount - Address of a variable that receives the number of
// elements in the index vector.
//
static HRESULT
WINAPI
EngineAdapterQueryIndexVectorSize(
__inout PWINBIO_PIPELINE Pipeline,
__out PSIZE_T IndexElementCount
)
{
HRESULT hr = S_OK;
// Verify that pointer arguments are not NULL.
if (!ARGUMENT_PRESENT(Pipeline) ||
!ARGUMENT_PRESENT(IndexElementCount))
{
hr = E_POINTER;
goto cleanup;
}
// Specify the number of index vector elements supported by your adapter. This can
// be any positive value or zero. Return zero if your adapter does not support placing
// templates into buckets. That is, return zero if your adapter does not support index
// vectors.
*IndexElementCount = NUMBER_OF_TEMPLATE_BINS;
cleanup:
return hr;
}
Requirements
Requirement | Value |
---|---|
Minimum supported client | Windows 7 [desktop apps only] |
Minimum supported server | Windows Server 2008 R2 [desktop apps only] |
Target Platform | Windows |
Header | winbio_adapter.h (include Winbio_adapter.h) |
See also
Feedback
https://aka.ms/ContentUserFeedback.
Coming soon: Throughout 2024 we will be phasing out GitHub Issues as the feedback mechanism for content and replacing it with a new feedback system. For more information see:Submit and view feedback for