DOKK / manpages / debian 11 / libwayland-doc / wl_listener.3.en
wl_listener(3) Wayland wl_listener(3)

wl_listener - A single listener for Wayland signals.

#include <wayland-server-core.h>


struct wl_list link
wl_notify_func_t notify

A single listener for Wayland signals.

wl_listener provides the means to listen for wl_signal notifications. Many Wayland objects use wl_listener for notification of significant events like object destruction.

Clients should create wl_listener objects manually and can register them as listeners to signals using wl_signal_add, assuming the signal is directly accessible. For opaque structs like wl_event_loop, adding a listener should be done through provided accessor methods. A listener can only listen to one signal at a time.

struct wl_listener your_listener;
your_listener.notify = your_callback_method;
// Direct access
wl_signal_add(&some_object->destroy_signal, &your_listener);
// Accessor access
wl_event_loop *loop = ...;
wl_event_loop_add_destroy_listener(loop, &your_listener);

If the listener is part of a larger struct, wl_container_of can be used to retrieve a pointer to it:

void your_listener(struct wl_listener *listener, void *data)
{

struct your_data *data;
your_data = wl_container_of(listener, data, your_member_name); }

If you need to remove a listener from a signal, use wl_list_remove().

wl_list_remove(&your_listener.link);

See also

wl_signal

wl_notify_func_t wl_listener::notify

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Mon Aug 31 2020 Version 1.18.0