I seem to understand it. `nested' is seen non-null value in the thread
_that executes the action_. In any other threads, the default null value
will be seen. And in the executing thread, after pending sends are
released, no user code will be executed, so no actions will be dropped.
Best Regards
Hmm, I didn't read the definition of `board-map' carefully. It seems the
second form
(dosync (board-map deref board))
is the best among the three, as it views `board' as a whole. The other two
might have the potential problem of printing incoordinated values of
entries in `board', i.e. the e
gt;>> 3: 5
>>> 4: 6
>>> 5: 7
>>> 6: 8
>>> 7: 9
>>> 8: 10
>>> 9: 11
Meaning the `dosync' form in the thread is retried twice, due to the two
passes of changing of the values in `data'. So using `dosync' to surround
the whol
