SYSTEM_POWER_STATE enumeration (wdm.h)

  • Article

The SYSTEM_POWER_STATE enumeration type is used to indicate a system power state.

Syntax

typedef enum _SYSTEM_POWER_STATE {
  PowerSystemUnspecified,
  PowerSystemWorking,
  PowerSystemSleeping1,
  PowerSystemSleeping2,
  PowerSystemSleeping3,
  PowerSystemHibernate,
  PowerSystemShutdown,
  PowerSystemMaximum
} SYSTEM_POWER_STATE, *PSYSTEM_POWER_STATE;

Constants

 
PowerSystemUnspecified
Indicates an unspecified system power state.
PowerSystemWorking
Indicates maximum system power, which corresponds to system working state S0.
PowerSystemSleeping1
Indicates a system sleeping state less than PowerSystemWorking and greater than PowerSystemSleeping2, which corresponds to system power state S1.
PowerSystemSleeping2
Indicates a system sleeping state less than PowerSystemSleeping1 and greater than PowerSystemSleeping3, which corresponds to system power state S2.
PowerSystemSleeping3
Indicates a system sleeping state less than PowerSystemSleeping2 and greater than PowerSystemHibernate, which corresponds to system power state S3.
PowerSystemHibernate
Indicates the lowest-powered sleeping state, which corresponds to system power state S4.
PowerSystemShutdown
Indicates the system is turned off, which corresponds to system shutdown state S5.
PowerSystemMaximum
The number of system power state values for this enumeration type that represents actual power states. This value is the number of elements in the DeviceState member of the DEVICE_CAPABILITIES structure for a device. The other system power state values are less than this value.

Remarks

A power state indicates the level of power consumption—and thus the extent of computing activity—by the system or by a single device. The power manager sets the power state of the system as a whole, where the system power state is indicated by one of the values of the SYSTEM_POWER_STATE enumeration type. Device drivers set the power state of their individual devices, where the device power state is indicated by one of the values of the DEVICE_POWER_STATE enumeration type.

For more information about system power states, see Handling System Power State Requests and for more information about device power states, see Managing Power for Individual Devices.

For more information about power management in general, see Introduction to Power Management.

Requirements

Requirement Value
Header wdm.h (include Wdm.h, Ntddk.h, Ntifs.h, Ntpoapi.h)

See also

DEVICE_POWER_STATE