EngineAdapterNotifyPowerChange callback function
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.
HRESULT WINAPI EngineAdapterNotifyPowerChange( _Inout_ PWINBIO_PIPELINE Pipeline, _In_ ULONG PowerEventType );
- Pipeline [in, out]
Pointer to the WINBIO_PIPELINE structure associated with the biometric unit performing the operation.
- PowerEventType [in]
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).)
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.
- E_POINTER (The Pipeline argument was NULL.)
- E_INVALIDARG (The PowerEventType argument was not one of the values listed in the table.)
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.
Minimum supported client
|Windows 8 [desktop apps only]|
Minimum supported server
|Windows Server 2012 [desktop apps only]|