Libuv

libuv
Stable release	1.51.0[1]  / 25 April 2025; 4 months ago (25 April 2025)
Repository	github.com/libuv/libuv
Written in	C
Operating system	Cross-platform
Platform	Linux, Android, Windows and OS X/Darwin,[2] FreeBSD, OpenBSD
Type	I/O abstraction library
License	MIT
Website	libuv.org

libuv is a multi-platform C library that provides support for asynchronous I/O based on event loops. It supports epoll(4), kqueue(2), Windows IOCP, Solaris event ports and Linux io_uring. It is primarily designed for use in Node.js but it is also used by other software projects.^[3] It was originally an abstraction around libev or Microsoft IOCP, as libev does not support IOCP on Windows. In node-v0.9.0's version of libuv, the dependency on libev was removed.^[4]

From:^[2]

• Full-featured event loop backed by epoll, kqueue, IOCP, event ports
• Asynchronous TCP and UDP sockets
• Asynchronous DNS resolution
• Asynchronous file and file system operations
• File system events
• ANSI escape code controlled TTY
• IPC with socket sharing, using Unix domain sockets or named pipes (Windows)
• Child processes
• Thread pool
• Signal handling
• High resolution clock
• Threading and synchronization primitives

According to libuv developer Ben Noordhuis, the name libuv originally had no specific meaning, but as people kept asking about it, so they made something up. They came up with Unicorn Velociraptor, which became the logo of the library.^[5]

• libevent
• Reactor pattern

• Official website
• libuv on GitHub
• An Introduction to libuv
• libuv API documentation
• libuv design overview