I need to match the text '\0' with the same regex that I would match 'a' or 'b'. (a regex for a character constant in C++). I've tried a bunch of different regexes, but haven't gotten a successful one yet. My latest attempt:

```
^['].|\\0[']

```

Most of the other things I've tried have given seg faults, so this is really the closest I've gotten.