C function to convert an NTSTATUS code into a Win32 error code - alternative to RtlNtStatusToDosError()

ntstatuserror.c

#include <windows.h>

/*
 * This is an alternative to the RtlNtStatusToDosError()
 * function in ntdll.dll.  It uses the GetOverlappedResult()
 * function in kernel32.dll to do the conversion.
 */
DWORD
ConvertNtStatusToWin32Error(LONG ntstatus)
{
        DWORD oldError;
        DWORD result;
        DWORD br;
        OVERLAPPED o;
 
        o.Internal = ntstatus;
        o.InternalHigh = 0;
        o.Offset = 0;
        o.OffsetHigh = 0;
        o.hEvent = 0;
        oldError = GetLastError();
        GetOverlappedResult(NULL, &o, &br, FALSE);
        result = GetLastError();
        SetLastError(oldError);
        return result;
}

@sergio-nsk GetOverlappedResult is expected to fail. ConvertNtStatusToWin32Error(0xC0000022L) should return 5, mapping STATUS_ACCESS_DENIED to ERROR_ACCESS_DENIED.

You are right, it is working well now. Don't know what it was recently, always returned 87.