Byte precision pointer arithmetic in C when sizeof(char) != 1

Question

How can one portably perform pointer arithmetic with single byte precision?

Keep in mind that:

• char is not 1 byte on all platforms

Answer 1

Cast the pointer to a uintptr_t. This will be an unsigned integer that is the size of a pointer. Now do your arithmetic on it, then cast the result back to a pointer of the type you want to dereference.

(Note that intptr_t is signed, which is usually NOT what you want! It's safer to stick to uintptr_t unless you have a good reason not to!)