An event notification library

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. Furthermore, libevent also support callbacks due to signals or regular timeouts. Currently, libevent supports /dev/poll, kqueue(2), event ports, POSIX select(2), Windows select(), poll(2), and epoll(4). Libevent additionally provides a sophisticated framework for buffered network IO, with support for sockets, filters, rate-limiting, SSL, zero-copy file transmission, and IOCP. Libevent includes support for several useful protocols, including DNS, HTTP, and a minimal RPC framework.