The libevent API provides a mechanism to execute a callback function
when a specific event occurs on a file descriptor or after a timeout
has been reached.

libevent is meant to replace the asynchronous event loop found in
event driven network servers. An application just needs to call
event_dispatch() and can then add or remove events dynamically
without having to change the event loop.

Currently, libevent supports kqueue(2) and select(2). Support for
poll(2) and /dev/poll is planned. The internal event mechanism is
completely independent of the exposed event API, and a simple update
of libevent can provide this new functionality without having to
redesign the server applications.

WWW: http://www.monkey.org/~provos/libevent/

- Pete
petef@databits.net