Finalizers etcetera

[Simon Peyton-Jones]

| (a) It was the first mention of MVars that I found in the docs.
| (b) I only really mentioned it because the type sigs are wrong.

Hmm.  That's not very clever.

| Doesn't it block if another thread manages to sneak a putMVar into
| the middle?  Maybe I should read your "Awkward Squad" paper to find
| out if this matters.

Yes it does block if another thread sneaks in a put.  If it matters,
you'd better code up a more robust abstraction (using MVars of course).

S