RtlUpcaseUnicodeStringToCountedOemString - NtDoc

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

#ifndef _NTRTL_H

NTSYSAPI
NTSTATUS
NTAPI
RtlUpcaseUnicodeStringToCountedOemString(
    _Inout_ POEM_STRING DestinationString,
    _In_ PUNICODE_STRING SourceString,
    _In_ BOOLEAN AllocateDestinationString
    );

#endif
View code on GitHub

This function is documented in Windows Driver Kit.

Edit description on GitHub