NtSaveMergedKeys - NtDoc

#ifndef _NTREGAPI_H

/**
 * Merges two registry keys and saves the result to a file.
 * 
 * @param HighPrecedenceKeyHandle Handle to the high precedence registry key.
 * @param LowPrecedenceKeyHandle Handle to the low precedence registry key.
 * @param FileHandle Handle to the file where the merged key will be saved.
 * @return NTSTATUS Successful or errant status.
 */
NTSYSCALLAPI
NTSTATUS
NTAPI
NtSaveMergedKeys(
    _In_ HANDLE HighPrecedenceKeyHandle,
    _In_ HANDLE LowPrecedenceKeyHandle,
    _In_ HANDLE FileHandle
    );

#endif
View code on GitHub

#ifndef _NTZWAPI_H

NTSYSCALLAPI
NTSTATUS
NTAPI
ZwSaveMergedKeys(
    _In_ HANDLE HighPrecedenceKeyHandle,
    _In_ HANDLE LowPrecedenceKeyHandle,
    _In_ HANDLE FileHandle
    );

#endif
View code on GitHub