RtlGenerate8dot3Name - NtDoc

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

// private
NTSYSAPI
NTSTATUS
NTAPI
RtlGenerate8dot3Name(
    _In_ PUNICODE_STRING Name,
    _In_ BOOLEAN AllowExtendedCharacters,
    _Inout_ PGENERATE_NAME_CONTEXT Context,
    _Inout_ PUNICODE_STRING Name8dot3
    );

#endif

View code on GitHub

This function is documented in Windows Driver Kit.