RtlSecondsSince1970ToTime - NtDoc

Native API online documentation, based on the System Informer (formerly Process Hacker) phnt headers
#ifndef _NTRTL_H

NTSYSAPI
VOID
NTAPI
RtlSecondsSince1970ToTime(
    _In_ ULONG ElapsedSeconds,
    _Out_ PLARGE_INTEGER Time
    );

#endif

View code on GitHub

This function is documented in Windows Driver Kit.