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4/8/2010

This structure is used to issue power notification events through message queues.

Syntax 

struct {
  DWORD 
Message;
  DWORD 
Flags;
  DWORD 
Length;
  WCHAR 
SystemPowerState[1];
} POWER_BROADCAST, *PPOWER_BROADCAST;

Members

Message

This field defines the event type. Set to one of the events shown in the following table.

Event type Description

PBT_POWERSTATUSCHANGE

Power supply switched to/from AC/DC.

PBT_RESUME

Resume from previous state.

PBT_TRANSITION

System power state transition.
Flags

Use one of the system power flags shown in the following table.

System power flag Description

POWER_STATE_BOOT

Boot state.

POWER_STATE_CRITICAL

Critical off.

POWER_STATE_IDLE

Idle state.

POWER_STATE_ON

On state.

POWER_STATE_OFF

No power, full off.

POWER_STATE_RESET

Reset state.

POWER_STATE_SUSPEND

Suspended state.
Length

The byte count of SystemPowerState.

SystemPowerState

The named system power state Flags.

Remarks

Applications and drivers register for power events with RequestPowerNotificationsand unregister with StopPowerNotifications. Power notification events are issued in a POWER_BROADCASTstructure, through message queues.

These notifications are multicast messages that are sent only to applications and drivers that have registered to receive the messages.

See Also