Very true, also `array_size` should be `size_t` (though that wouldn't solve the issue).

```c
bool msgpack_rpc_array_result(char **result, msgpack_object *req, msgpack_packer *res) {
  size_t array_size;
  for (array_size = 0; *(ptr + array_size) != NULL; array_size++) continue;

  // ...
}
```