> I don't have a strong feeling about what approach is right here.  One
> thing that would help: Does anyone have an idea how common it is for
> people to use non-string (or even non-ASCII) values in environment
> variables?  I had never heard of anyone using them for binary data
> before.  It seems like asking for trouble, but perhaps I'm missing
> something.

Non-string binary data is asking for trouble (and strings containing
null bytes cannot be represented).

Non-ASCII data almost certainly exists (e.g. people's names and
filenames using international characters).