Your problem is that pointer arithmetic is dependent on the size of what the
pointer is pointing to:

int myArray[12];
int * test = &myArray[0];
test++;

the ++ operation moves the pointer not 1 byte, but sizeof(*test) bytes so
thaty it points to myArray[1];
void * does not have a type, so the compiler does not know what it should do
when + and - are applied. It does not point to anything that can be used for
size.

the solution is to cast to so what you mean it to be.
If you really want to do pointer aritmetic on a byte by byte basis, you have
to cast your pointer to char *.