RequestPowerNotifications

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4/8/2010

This function enables applications and drivers to register for power notification events.

Syntax

HANDLE RequestPowerNotifications(
  HANDLE hMsgQ,
  DWORD Flags
);

hMsgQ
[in] Handle to the application message queue created with CreateMsgQueue. CreateMsgQueue requires a pointer to a MSGQUEUEOPTIONS structure. Set the cbMaxMessage parameter of the MSGQUEUEOTPIONS structure to sizeof(POWER_BROADCAST) + (MAX_PATH * sizeof TCHAR).

Flags
[in] Set to the logical OR of the desired PBT_XXX notifications, or to POWER_NOTIFY_ALL to receive all notifications.

The following table shows the notifications.

Notification	Description
PBT_POWERINFOCHANGE	Broadcast specifying that a battery power status field has changed. This notification has an associated POWER_BROADCAST_POWER_INFO structure.
PBT_POWERSTATUSCHANGE	Broadcast specifying that the power supply has switched either from AC to DC or from DC to AC.
PBT_RESUME	Broadcast notifying that the system is resuming and specifies the previous state.
PBT_TRANSITION	Broadcast specifying the system power state transition.

Nonzero indicates success. Zero indicates failure. To get extended error information, call GetLastError.

Power notification events are issued in a POWER_BROADCAST structure through message queues.