Notifier reentrancy is an issue in
asynchronous network programming on the
MacOS (and possibly elsewhere). Your program interacts with the network through a
notifier function that notifies you if certain things have happened -- for instance, if there is
data waiting to be received.
A problem arises if you fail to handle notifications properly -- your notifier function could be
called from within itself.
Reentering the notifier in such a way tends to lead to
infinite loops and other
Very Bad Things.
Mostly, however, it's fun to say '
notifier reentrancy'.