Should memchr work with invalid data size?

[H.J. Lu]

"main memchr" says

The  memchr()  function  scans  the  initial n bytes of the memory area
pointed to by s for the first instance of c.

But test-memchr.c has

      if (pos < len)
        {
          size_t r = random ();
          if ((r & 31) == 0)
            len = ~(uintptr_t) (p + align) - ((r >> 5) & 31);
          result = (CHAR *) (p + pos + align);
        }

which sets len to some random value, like 18446603336355475958.
Should memchr work with it?


-- 
H.J.