kqueue(2) on macOS
The text 4712183febaf, as OS X 10.10.2, OS X 10.10.1, OS X 10.10, OS X 10.9.5, OS X 10.9.4, OS X 10.9.3, OS X 10.9.2, OS X 10.9.1, OS X 10.9 shipped it.
kernel event notification mechanism
The text 4712183febaf, as OS X 10.10.2, OS X 10.10.1, OS X 10.10, OS X 10.9.5, OS X 10.9.4, OS X 10.9.3, OS X 10.9.2, OS X 10.9.1, OS X 10.9 shipped it.
kernel event notification mechanism