At present, only libevent, libev, and Boost ASIO are commonly used in the market. The most famous in the industry should be ACE, but it is a heavyweight online library.

Libevent is a network library written in C language. The official support is a linux-like operating system, and the latest version adds support for windows IOCP. In terms of cross-platform, it is mainly supported by select model.

Boost ASIO is an asynchronous IO library, which encapsulates the common operations of socket and simplifies the program development based on Socket. Support cross-platform.

Libev is written in C language and only supports libraries of linux system. The usage method is similar to libevent, but it is very concise and has the least code. Cross-platform support is not good, if you only need to run under linux, it is still possible.

ACE is a large middleware product, with about 200,000 lines of code, which is too grand. A bunch of design patterns are built layer by layer. It depends on the situation when you use it, and on which level you use it. Support cross-platform.