RtlMapGenericMask - NtDoc

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

NTSYSAPI
VOID
NTAPI
RtlMapGenericMask(
    _Inout_ PACCESS_MASK AccessMask,
    _In_ PGENERIC_MAPPING GenericMapping
    );

#endif

View code on GitHub

This function is documented in Windows Driver Kit.