An asynchronous event notification library (core) 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. Currently, libevent supports /dev/poll, kqueue(2), event ports, select(2), poll(2) and epoll(4). The libevent_core library includes event loops, timers, buffer code, and various small compatibility functions. If you're writing software that only uses libevent's event loop, you should link against only the libevent_core library.