Kqueue is a scalable event notification interface introduced in FreeBSD 4.1 on July 2000, also supported in NetBSD, OpenBSD, DragonFly BSD, and macOS. Kqueue was originally authored in 2000 by Jonathan Lemon, then involved with the FreeBSD Core Team. Kqueue makes it possible for software like nginx to solve the c10k problem. Some other operating systems which traditionally only supported select(2) and poll(2) also currently provide more efficient polling alternatives, such as epoll on Linux and I/O completion ports on Windows and Solaris.