SetSystemPowerState (Windows CE 5.0)

Article
09/14/2012

This function sets the system power state to the requested value.

DWORD SetSystemPowerState(LPCWSTR psState,DWORD StateFlags,DWORD Options);

Parameters

psState
[in] Names the desired system state to enter. If this parameter is not NULL then the StateFlags parameter is ignored.

StateFlags
[in] Optional. If the psState parameter is NULL then names the system power state using the POWER_STATE_XXX flags defined in Pm.h.

The following table shows the various Power_State_XXX flags.

Flag	Description
POWER_STATE_ON	On state
POWER_STATE_OFF	Off state
POWER_STATE_CRITICAL	Critical state
POWER_STATE_BOOT	Boot state
POWER_STATE_IDLE	Idle state
POWER_STATE_SUSPEND	Suspend state
POWER_STATE_RESET	Reset state

Options
[in] Uses the optional POWER_FORCE flag to indicate that the state transfer is urgent. The interpretation of this flag is platform dependent.

Return Values

ERROR_SUCCESS
System power state has been set successfully.
Win32 error code
System power state was not set.

Remarks

If the requested power state transition causes the system to suspend, this function returns only after system operation resumes and related PBT_RESUME messages have been broadcast in the POWER_BROADCAST structure. Some platforms may restrict which system power states can be set by applications.

System power states define maximum device power levels for all power-manageable devices in the system. If a device is already at or below the maximum power level mandated by the new system power state, the device power state will not be updated.

If a system call explicitly puts the device into an idle state, to activate the device when an application calls SetSystemPowerState(POWER_STATE_SUSPEND), an appropriate wake source event must be implemented on the target device. For more information, see Power Management Wake Sources.

Windows Mobile Remarks

The POWER_STATE_IDLE flag for the StateFlags parameter is set to Screen off for Windows Mobile-based devices. In additon, the StateFlags parameter can also be set to the POWER_STATE_USERIDLE state for Windows Mobile-based devices

The Options parameter can be set to POWER_DUMPDW to generate a Watson error report.

Requirements

OS Versions: Windows CE .NET 4.0 and later.
Header: Pm.h.
Link Library: Coredll.lib.

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