RtlRandom - NtDoc

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

_Ret_range_(<=, MAXLONG)
NTSYSAPI
ULONG
NTAPI
RtlRandom(
    _Inout_ PULONG Seed
    );

#endif

View code on GitHub
/*
 * RTL forward symbol typedefs
 *
 * This file is part of System Informer.
 */
#ifndef _NTRTL_FWD_H
// begin_forwarders
#ifndef PHNT_INLINE_NAME_FORWARDERS

#define RtlRandom RtlRandomEx

#endif
// end_forwarders
#endif

View code on GitHub

This function is documented in Windows Driver Kit.