NtUnloadKeyEx - NtDoc

#ifndef _NTREGAPI_H

/**
 * Unloads a registry key and optionally signals an event.
 * 
 * @param TargetKey Pointer to the object attributes of the target key.
 * @param Event Optional handle to an event to be signaled.
 * @return NTSTATUS Successful or errant status.
 */
NTSYSCALLAPI
NTSTATUS
NTAPI
NtUnloadKeyEx(
    _In_ POBJECT_ATTRIBUTES TargetKey,
    _In_opt_ HANDLE Event
    );

#endif
View code on GitHub

#ifndef _NTZWAPI_H

NTSYSCALLAPI
NTSTATUS
NTAPI
ZwUnloadKeyEx(
    _In_ POBJECT_ATTRIBUTES TargetKey,
    _In_opt_ HANDLE Event
    );

#endif
View code on GitHub