PIBIO_ENGINE_NOTIFY_POWER_CHANGE_FN callback function (winbio_adapter.h)
Called by the Windows Biometric Framework when the computer is ready to enter a low-power state or when the computer has been awakened from a low-power state. The purpose of this function is to enable the adapter to respond to transitions in the computer power state.
Syntax
PIBIO_ENGINE_NOTIFY_POWER_CHANGE_FN PibioEngineNotifyPowerChangeFn;
HRESULT PibioEngineNotifyPowerChangeFn(
[in, out] PWINBIO_PIPELINE Pipeline,
[in] ULONG PowerEventType
)
{...}
Parameters
[in, out] Pipeline
Pointer to the WINBIO_PIPELINE structure associated with the biometric unit performing the operation.
[in] PowerEventType
Indicates the nature of the change. It can be one of the following values:
- PBT_APMSUSPEND
The system is entering a low-power state.
- PBT_APMRESUMEAUTOMATIC
The system is returning from a low-power state.
- PBT_APMPOWERSTATUSCHANGE
The status of the system's power source is changing (e.g. the system has switched from battery to line power, or the battery is getting low).
Return value
If the function succeeds, it returns S_OK. If the function fails, 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.
Remarks
When it receives a PBT_APMPOWERSTATUSCHANGE event, the adapter should call the Microsoft Win32GetSystemPowerStatus API to determine the new power status.
The biometric framework calls this adapter entry point asynchronously in the context of an arbitrary thread. It is the responsibility of the adapter to synchronize processing of this call with any other work it may be doing.
Requirements
| Requirement | Value |
|---|---|
| Minimum supported client | Windows 8 [desktop apps only] |
| Minimum supported server | Windows Server 2012 [desktop apps only] |
| Target Platform | Windows |
| Header | winbio_adapter.h |