ref: 0c6d4405d1f0232497145a46f3e315b9db20187e
dir: /lib/c/memcmp.c/
#include <string.h>
#undef memcmp
int
memcmp(const void *s1, const void *s2, size_t n)
{
char *s = (char *) s1, *t = (char *) s2;
while (n > 0 && *s == *t)
--n, ++s, ++t;
return n ? (*s - *t) : 0;
}