WinBioMonitorPresence function (winbio.h)

Article
02/22/2024

Turns on the face-recognition or iris-monitoring mechanism for the specified biometric unit. Starting with Windows 10, build 1607, this function is available to use with a mobile image.

Syntax

HRESULT WinBioMonitorPresence(
  [in] WINBIO_SESSION_HANDLE SessionHandle,
  [in] WINBIO_UNIT_ID        UnitId
);

Parameters

[in] SessionHandle

An asynchronous handle for the biometric session that you obtained by calling the WinBioAsyncOpenSession function with the PoolType parameter set to WINBIO_POOL_SYSTEM.

[in] UnitId

The identifier of the biometric unit for which you want to turn on the face-recognition or iris-monitoring mechanism.

Return value

If the function parameters are acceptable, it returns S_OK. If the function parameters are not acceptable, it returns an HRESULT value that indicates the error.
Possible values include, but are not limited to, those in the following table. For a list of common error codes, see Common HRESULT Values.

Return code	Description
E_HANDLE	The session handle is not valid.
E_INVALIDARG	The UnitId parameter cannot equal zero.
WINBIO_E_INCORRECT_SESSION_TYPE	The session handle does not correspond to an asynchronous biometric session.

The actual success or failure of the operation itself is returned to the your notification function in a WINBIO_ASYNC_RESULT structure.

Remarks

A single biometric session can have only one active presence monitor at any point in time.

After you successfully call WinBioMonitorPresence, your notification function receives notifications in the form of a WINBIO_ASYNC_RESULT structure with an Operation member equal to WINBIO_OPERATION_MONITOR_PRESENCE. You should then examine the Parameters.MonitorPresence member of the WINBIO_ASYNC_RESULT structure for more information.

To stop receiving notifications, call either WinBioCancel or WinBioCloseSession with the original asynchronous handle value.

Requirements

Requirement	Value
Minimum supported client	Windows 10 [desktop apps only]
Minimum supported server	Windows Server 2016 [desktop apps only]
Target Platform	Windows
Header	winbio.h
Library	Winbio.lib
DLL	Winbio.dll