RtlUShortSub - NtDoc

#ifndef _NTINTSAFE_H_INCLUDED_
#if WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_APP | WINAPI_PARTITION_SYSTEM | WINAPI_PARTITION_GAMES)

//
// USHORT subtraction
//
_Must_inspect_result_
__inline
NTSTATUS
RtlUShortSub(
    _In_ USHORT usMinuend,
    _In_ USHORT usSubtrahend,
    _Out_ _Deref_out_range_(==, usMinuend - usSubtrahend) USHORT* pusResult)
{
    NTSTATUS status;

    if (usMinuend >= usSubtrahend)
    {
        *pusResult = (USHORT)(usMinuend - usSubtrahend);
        status = STATUS_SUCCESS;
    }
    else
    {
        *pusResult = USHORT_ERROR;
        status = STATUS_INTEGER_OVERFLOW;
    }
    
    return status;
}

#endif
#endif
View code on GitHub