RtlConvertLongToLuid - NtDoc

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

FORCEINLINE
LUID
NTAPI_INLINE
RtlConvertLongToLuid(
    _In_ LONG Long
    )
{
    LUID tempLuid;

    tempLuid.LowPart = Long;
    tempLuid.HighPart = 0;

    return tempLuid;
}

#endif

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This function is documented in Windows Driver Kit.

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