register int c1, c2, l = 0;  while (*s1 && *s2 && l < n) { c1 = tolower (*s1); c2 = tolower (*s2); if (c1 != c2) return (c1 - c2); s1++; s2++; l++; }
register int c1, c2, l = 0;  while (*s1 && *s2 && l < n) { c1 = tolower (*s1); c2 = tolower (*s2); if (c1 != c2) return (c1 - c2); s1++; s2++; l++; } if (l == n)
int strncasecmp (char *s1, char *s2, size_t n){    register int c1, c2, l = 0;    while (*s1 && *s2 && l < n)    {      c1 = tolower (*s1);      c2 = tolower (*s2);      if (c1 != c2)	return (c1 - c2);      s1++;      s2++;      l++;    }    return (int) (0);}