NtSetSystemPowerState - NtDoc

#ifndef _NTPOAPI_H

NTSYSCALLAPI
NTSTATUS
NTAPI
NtSetSystemPowerState(
    _In_ POWER_ACTION SystemAction,
    _In_ SYSTEM_POWER_STATE LightestSystemState,
    _In_ ULONG Flags // POWER_ACTION_* flags
    );

#endif
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#ifndef _NTZWAPI_H

NTSYSCALLAPI
NTSTATUS
NTAPI
ZwSetSystemPowerState(
    _In_ POWER_ACTION SystemAction,
    _In_ SYSTEM_POWER_STATE LightestSystemState,
    _In_ ULONG Flags // POWER_ACTION_* flags
    );

#endif
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