static int iscleared (global_State *g, const GCObject *o) {
  if (o == NULL) return 0;  /* non-collectable value */
  else if (novariant(o->tt) == LUA_TSTRING) {
    markobject(g, o);  /* strings are 'values', so are never weak */
    return 0;
  }
  else return iswhite(o);
}
Unknown