wl_signal(3)                        Wayland                       wl_signal(3)

NAME
       wl_signal - A source of a type of observable event.


SYNOPSIS
       #include <wayland-server-core.h>

   Public Member Functions
       void wl_signal_emit_mutable (struct wl_signal *signal, void *data)

   Static Public Member Functions
       static void wl_signal_init (struct wl_signal *signal)
       static void wl_signal_add (struct wl_signal *signal, struct wl_listener
           *listener)
       static struct wl_listener * wl_signal_get (struct wl_signal *signal,
           wl_notify_func_t notify)
       static void wl_signal_emit (struct wl_signal *signal, void *data)

   Data Fields
       struct wl_list listener_list

Detailed Description
       A source of a type of observable event.

       Signals are recognized points where significant events can be observed.
       Compositors as well as the server can provide signals. Observers are
       wl_listener's that are added through wl_signal_add. Signals are emitted
       using wl_signal_emit, which will invoke all listeners until that
       listener is removed by wl_list_remove() (or whenever the signal is
       destroyed).

       See also
           wl_listener for more information on using wl_signal

Member Function Documentation
   static void wl_signal_add (struct wl_signal * signal, struct wl_listener *
       listener) [inline],  [static]
       Add the specified listener to this signal.

       Parameters
           signal The signal that will emit events to the listener
           listener The listener to add

   static void wl_signal_emit (struct wl_signal * signal, void * data)
       [inline],  [static]
       Emits this signal, notifying all registered listeners.

       Parameters
           signal The signal object that will emit the signal
           data The data that will be emitted with the signal

   void wl_signal_emit_mutable (struct wl_signal * signal, void * data)
       Emits this signal, notifying all registered listeners.

       A safer version of wl_signal_emit() which can gracefully handle
       additions and deletions of any signal listener from within listener
       notification callbacks.

       Listeners deleted during a signal emission and which have not already
       been notified at the time of deletion are not notified by that
       emission.

       Listeners added (or readded) during signal emission are ignored by that
       emission.

       Note that repurposing a listener without explicitly removing it and
       readding it is not supported and can lead to unexpected behavior.

       Parameters
           signal The signal object that will emit the signal
           data The data that will be emitted with the signal

       Since
           1.20.90

   static struct wl_listener * wl_signal_get (struct wl_signal * signal,
       wl_notify_func_t notify) [inline],  [static]
       Gets the listener struct for the specified callback.

       Parameters
           signal The signal that contains the specified listener
           notify The listener that is the target of this search

       Returns
           the list item that corresponds to the specified listener, or NULL
           if none was found

   static void wl_signal_init (struct wl_signal * signal) [inline],  [static]
       Initialize a new wl_signal for use.

       Parameters
           signal The signal that will be initialized

Field Documentation
   struct wl_list wl_signal::listener_list

Author
       Generated automatically by Doxygen for Wayland from the source code.

Version 1.22.0                  Thu Apr 6 2023                    wl_signal(3)