What is "event-driven programming"

n. (context programming paradigm English) A programming paradigm where the flow of the program is determined by events.

In computer programming, event-driven programming is a programming paradigm in which the flow of the program is determined by events such as user actions ( mouse clicks, key presses), sensor outputs, or messages from other programs/ threads. Event-driven programming is the dominant paradigm used in graphical user interfaces and other applications (e.g. JavaScript web applications) that are centered on performing certain actions in response to user input.

In an event-driven application, there is generally a main loop that listens for events, and then triggers a callback function when one of those events is detected. In embedded systems the same may be achieved using hardware interrupts instead of a constantly running main loop. Event-driven programs can be written in any programming language, although the task is easier in languages that provide high-level abstractions, such as closures.