You can call into the kernel just fine in Windows. The fact you use a function call wrapper instead of a raw syscall is not really relevant.
Most Windows NT kernel functions take a buffer to use rather than allocating their own memory. Even many Win32 functions don't allocate (although there you have to be much more careful).
Most Windows NT kernel functions take a buffer to use rather than allocating their own memory. Even many Win32 functions don't allocate (although there you have to be much more careful).