Function isinstack

depends/lua/src/ldebug.c:547–550

** The subtraction of two potentially unrelated pointers is ** not ISO C, but it should not crash a program; the subsequent ** checks are ISO C and ensure a correct result. */

** checks are ISO C and ensure a correct result.
*/
static int isinstack (CallInfo *ci, const TValue *o) {
  ptrdiff_t i = o - ci->u.l.base;
  return (0 <= i && i < (ci->top - ci->u.l.base) && ci->u.l.base + i == o);
}


/*