#ifndef _NTPOAPI_H

/**
 * The NtGetDevicePowerState routine retrieves the current power state of the specified device.
 *
 * \param Device A handle to an object on the device, such as a file or socket, or a handle to the device itself.
 * \param State A pointer to the variable that receives the power state.
 * \return Successful or errant status.
 * \remarks An application can use NtGetDevicePowerState to determine whether a device is in the working state or a low-power state.
 * If the device is in a low-power state, accessing the device may cause it to either queue or fail any I/O requests, or transition the device into the working state.
 * The exact behavior depends on the implementation of the device.
 */
NTSYSCALLAPI
NTSTATUS
NTAPI
NtGetDevicePowerState(
    _In_ HANDLE Device,
    _Out_ PDEVICE_POWER_STATE State
    );

#endif
View code on GitHub

#ifndef _NTZWAPI_H

NTSYSCALLAPI
NTSTATUS
NTAPI
ZwGetDevicePowerState(
    _In_ HANDLE Device,
    _Out_ PDEVICE_POWER_STATE State
    );

#endif
View code on GitHub