63.4. The epoll API

Like the I/O multiplexing system calls and signal-driven I/O, the Linux epoll (event poll) API is used to monitor multiple file descriptors to see if they are ready for I/O. The primary advantages of the epoll API are the following:

• The performance of epoll scales much better than select() and poll() when monitoring large numbers of file descriptors.

• The epoll API permits either level-triggered or edge-triggered notification. By contrast, select() and poll() provide only level-triggered notification, and signal-driven I/O provides only edge-triggered notification.