Application Power Management
The Power Manager is responsible for managing device power as defined in system power state registry entries.
The following table shows the power management APIs.
| Function | Description |
|---|---|
| GetDevicePower | Returns a device power state. |
| GetSystemPowerState | Returns the current system power state in effect. |
| GetSystemPowerStatusEx2 | Retrieves battery status information. |
| ReleasePowerRequirement | Informs the Power Manager to release a power requirement set by SetPowerRequirement. |
| RequestPowerNotifications | Allows applications and drivers to register for power notification events. |
| SetDevicePower | Sets device power state on a device. |
| SetPowerRequirement | Notifies the Power Manager that an application has a specific device power requirement. This function prevents the system from placing the named device into the default system state while the requirement is outstanding. |
| SetSystemPowerState | Sets the system power state to the requested value. Depending on the StateFlags parameter, the function either sets the state immediately or requests permission from all applications and device drivers before doing so. |
| StopPowerNotifications | Allows applications and drivers to stop receiving power notification events. |
Microsoft discourages application developers from calling SetDevicePower in their applications because it overrides the Power Manager algorithms for managing device power. Application developers should also not call SetSystemPowerState in their applications except to suspend the system, if the Power Manager is actively managing system power state transitions.
See Also
Power Management | How to Add Power Management to a Device Driver
Last updated on Tuesday, May 18, 2004
© 1992-2003 Microsoft Corporation. All rights reserved.