4. mem... functions
The mem... functions are meant for manipulating objects as character arrays.The intent is an interface to efficient routines which can be implemented using low-level machine instructions.
The pointer arguments are `void *' so they can accept any pointer type.
However, you can not use a void pointer to point to anything.
Therefore, these functions must use local `char *' variables initialized with their `void *' arguments, e.g.
int memcmp (const void *v1, const void *v2, size_t size)
{
const unsigned char *p1 = v1;
const unsigned char *p2 = v2;
... use p1 and p2 to access the elements of v1 and v2 ...
}