Question

If I would want to operate on pointers which point to one byte should I use void* or char*, because I heard that

sizeof(char)

isn’t always 1 byte, and what about void*? If I do

void *p
++p

will it point everywhere one byte further?

Answer 1

In C pointer arithmetic is not defined for void pointers. Pointer arithmetic is intrinsically tied to the size of the pointed type. And for void * the size of the pointed type is unknown.

To see how pointer arithmetic works for different objects, try this:

int obj[5];
int *ip = obj;
char *cp = (char *)obj;

ip++;
cp++;

printf("%p\n%p\n", ip, cp);

However, if the compiler does support it, pointer arithmetic on void pointers works the same as on char pointers.