https://learn.microsoft.com/en-us/windows-hardware/drivers/ddi/ntifs/nf-ntifs-rtlupcaseunicodetooemn
RtlUpcaseUnicodeToOemN function (ntifs.h) - Windows drivers | Microsoft Learn
The RtlUpcaseUnicodeToOemN routine translates a given Unicode string into an uppercase OEM string, using the current system OEM code page.
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