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PoSetSystemState routine

Drivers call the PoSetSystemState routine to indicate that the system is active.

Syntax


VOID PoSetSystemState(
  _In_  EXECUTION_STATE Flags
);

Parameters

Flags [in]

Indicates the system activity, as specified by a bitwise OR of one or more of the following values:

ES_SYSTEM_REQUIRED

The system is not idle, regardless of apparent load.

ES_DISPLAY_REQUIRED

Use of the display is required.

ES_USER_PRESENT

A user is present.

Return value

None

Remarks

A driver calls PoSetSystemState to set flags indicating that system activity is occurring. Unlike PoRegisterSystemState, this routine does not allow the driver to set a persistent busy state.

The Flags parameter specifies the type of activity occurring. Drivers can specify any combination of the flags.

Drivers can set the system busy state to request that the system avoid leaving of the working state while driver activity is occurring. Note, however, that under some circumstances (such as a critically low battery) the power manager may override this request and put the system to sleep anyway.

Requirements

Version

Available starting with Windows 2000.

Header

Wdm.h (include Wdm.h, Ntddk.h, or Ntifs.h)

Library

Ntoskrnl.lib

IRQL

<=DISPATCH_LEVEL

See also

PoRegisterSystemState
PoUnregisterSystemState

 

 

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