memcmp - compare memory blocks
Standard C Library (libc, -lc)
#include <string.h>
int
memcmp(const void *block1,
const void *block2,
size_t len);
The two memory regions block1 and block2, both of length len, are compared lexicographically.
If block1 sorts before block2, -1 is returned.
If block1 sorts after block2, 1 is returned.
If block1 is the same as block2, 0 is returned.
The sort order used is derived from the natural ordering of the numerical values of (unsigned) characters.