POWER_BROADCAST (Compact 2013)
3/26/2014
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_POWERINFOCHANGE
A member of the POWER_BROADCAST_POWER_INFO structure has changed.
You should not call GetBatteryStatusEx directly. Instead, register with Power Manager for a PBT_POWERINFOCHANGE that contains the same amount of information. The battery driver polls as necessary to extract data from the driver, and then pushes changes to Power Manager with PowerPolicyNotify.
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_BACKLIGHTON
Screen backlight is on.
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.
POWER_STATE_UNATTENDED
Unattended state.
POWER_STATE_USERIDLE
User idle state.
- Length
The byte count of SystemPowerState.
- SystemPowerState
The named system power state Flags.
Remarks
Applications and drivers register for power events with RequestPowerNotifications and unregister with StopPowerNotifications. Power notification events are issued in a POWER_BROADCAST structure, through message queues.
These notifications are multicast messages that are sent only to applications and drivers that have registered to receive the messages.
The POWER_BROADCAST structure has a variable length. The SystemPowerState array is a placeholder for data associated with the message being broadcast and is not always WCHAR data. For example, the PBT_POWERINFOCHANGE message embeds a POWER_BROADCAST_POWER_INFO structure.
Requirements
Header |
pm.h |
See Also
Reference
Power Management Structures
RequestPowerNotifications
StopPowerNotifications