#include <string.h>

int strncmp(const char* _l, const char* _r, size_t n) {
  const unsigned char *l = (void *)_l, *r = (void *)_r;
  if (!n--)
    return 0;
  for (; *l && *r && n && *l == *r; l++, r++, n--)
    ;
  return *l - *r;
}