RtlULongPtrSub - NtDoc

#ifndef _NTINTSAFE_H_INCLUDED_
#if WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_APP | WINAPI_PARTITION_SYSTEM | WINAPI_PARTITION_GAMES)
//
// ULONG_PTR subtraction
//
#ifdef _WIN64

#define RtlULongPtrSub RtlULongLongSub

#endif
#endif
#endif
View code on GitHub

#ifndef _NTINTSAFE_H_INCLUDED_
#if WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_APP | WINAPI_PARTITION_SYSTEM | WINAPI_PARTITION_GAMES)
//
// ULONG_PTR subtraction
//
#ifdef _WIN64
// ...
#else

_Must_inspect_result_
__inline
NTSTATUS
RtlULongPtrSub(
    _In_ ULONG_PTR ulMinuend,
    _In_ ULONG_PTR ulSubtrahend,
    _Out_ _Deref_out_range_(==, ulMinuend - ulSubtrahend) ULONG_PTR* pulResult)
{
    NTSTATUS status;

    if (ulMinuend >= ulSubtrahend)
    {
        *pulResult = (ulMinuend - ulSubtrahend);
        status = STATUS_SUCCESS;
    }
    else
    {
        *pulResult = ULONG_PTR_ERROR;
        status = STATUS_INTEGER_OVERFLOW;
    }
    
    return status;
}

#endif
#endif
#endif
View code on GitHub