GdkEvent

GdkEvent is a core data structure in the GDK (GIMP Drawing Kit) library used by GTK applications to represent a single event from the windowing system. It serves as a generic container for all kinds of input and window events that can occur while an application runs, such as keyboard input, mouse actions, and window changes. Each event type is identified by a type field, and the event-specific information is stored in a union of per-event structures.

Common event types include key presses and releases (GdkEventKey), button presses and releases (GdkEventButton), pointer motion (GdkEventMotion), scrolling (GdkEventScroll), window configure events for size and position changes (GdkEventConfigure), enter/leave and focus events, expose or paint requests (GdkEventExpose), and client or window state notifications. The exact fields available depend on the event type.

In GTK applications, event handlers receive a pointer to GdkEvent and typically use a switch on event->type to determine how to process the event, then access the appropriate fields via the corresponding event structure (for example, event->key for GdkEventKey, event->button for GdkEventButton). Many events are dispatched through widget signals such as button-press-event or key-press-event, but low-level handlers may observe GdkEvent pointers directly.

GdkEvent objects are owned by the GDK event system. They are valid for the duration of the callback and should not be freed by the application; if persistence is required, data should be copied into the application’s own structures.

Platform coverage: GDK abstracts over X11, Wayland, and other backends, providing a unified event API to GTK applications.