libev is described as 'full-featured and high-performance event loop that is loosely modelled after libevent, but without its limitations and bugs' and is an app in the Development category. There are three alternatives to libev for Linux, Mac, Windows and C++. The best alternative is libuv, which is both free and Open Source. Other great apps like libev are libevent (Free, Open Source) and Tokio (Free, Open Source).
libuv is a software library that provides asynchronous event notification. libuv supports epoll(4), kqueue(2), Windows IOCP, and Solaris event ports. It is primarily designed for use in Node.js but it is also used by other software projects.
libevent is an asynchronous event notification software 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.
Tokio is an open source library providing an asynchronous, event driven platform for building fast, reliable, and lightweight network applications. It leverages Rust's ownership and concurrency model to ensure thread safety. Tokio is a blazing fast, lightweight and reliable.