Editing Callback (computer programming) (section)

=== Event handling ===

A callback can be used for event handling. Often, consuming code registers a callback for a particular type of event. When that event occurs, the callback is called.

Callbacks are often used to program the [[graphical user interface]] (GUI) of a program that runs in a [[windowing system]]. The application supplies a reference to a custom callback function for the windowing system to call. The windowing system calls this function to notify the application of events like [[computer mouse|mouse]] clicks and [[computer keyboard|key]] presses.