Public Types¶

typedef int(* wl_event_loop_fd_func_t) (int fd, uint32_t mask, void *data)
typedef int(* wl_event_loop_timer_func_t) (void *data)
typedef int(* wl_event_loop_signal_func_t) (int signal_number, void *data)
typedef void(* wl_event_loop_idle_func_t) (void *data)

Public Member Functions¶

struct wl_event_source * wl_event_loop_add_fd (struct wl_event_loop *loop, int fd, uint32_t mask, wl_event_loop_fd_func_t func, void *data)
int wl_event_source_fd_update (struct wl_event_source *source, uint32_t mask)
struct wl_event_source * wl_event_loop_add_timer (struct wl_event_loop *loop, wl_event_loop_timer_func_t func, void *data)
int wl_event_source_timer_update (struct wl_event_source *source, int ms_delay)
struct wl_event_source * wl_event_loop_add_signal (struct wl_event_loop *loop, int signal_number, wl_event_loop_signal_func_t func, void *data)
struct wl_event_source * wl_event_loop_add_idle (struct wl_event_loop *loop, wl_event_loop_idle_func_t func, void *data)
void wl_event_source_check (struct wl_event_source *source)
int wl_event_source_remove (struct wl_event_source *source)

typedef int(* wl_event_loop_fd_func_t) (int fd, uint32_t mask, void *data)¶

File descriptor dispatch function type

Functions of this type are used as callbacks for file descriptor events.

Parameters

Returns

See also

typedef void(* wl_event_loop_idle_func_t) (void *data)¶

Idle task function type

Functions of this type are used as callbacks before blocking in wl_event_loop_dispatch().

Parameters

See also

typedef int(* wl_event_loop_signal_func_t) (int signal_number, void *data)¶

Signal dispatch function type

Functions of this type are used as callbacks for (POSIX) signals.

Parameters

Returns

See also

typedef int(* wl_event_loop_timer_func_t) (void *data)¶

Timer dispatch function type

Functions of this type are used as callbacks for timer expiry.

Parameters

Returns

See also

struct wl_event_source * wl_event_loop_add_fd (struct wl_event_loop * loop, int fd, uint32_t mask, wl_event_loop_fd_func_t func, void * data)¶

Create a file descriptor event source

Parameters

Returns

The given file descriptor is initially watched for the events given in mask. This can be changed as needed with wl_event_source_fd_update().

If it is possible that program execution causes the file descriptor to be read while leaving the data in a buffer without actually processing it, it may be necessary to register the file descriptor source to be re-checked, see wl_event_source_check(). This will ensure that the dispatch function gets called even if the file descriptor is not readable or writable anymore. This is especially useful with IPC libraries that automatically buffer incoming data, possibly as a side-effect of other operations.

See also

struct wl_event_source * wl_event_loop_add_idle (struct wl_event_loop * loop, wl_event_loop_idle_func_t func, void * data)¶

Create an idle task

Parameters

Returns

Idle tasks are dispatched before wl_event_loop_dispatch() goes to sleep. See wl_event_loop_dispatch() for more details.

Idle tasks fire once, and are automatically destroyed right after the callback function has been called.

An idle task can be cancelled before the callback has been called by wl_event_source_remove(). Calling wl_event_source_remove() after or from within the callback results in undefined behaviour.

See also

struct wl_event_source * wl_event_loop_add_signal (struct wl_event_loop * loop, int signal_number, wl_event_loop_signal_func_t func, void * data)¶

Create a POSIX signal event source

Parameters

Returns

This function blocks the normal delivery of the given signal in the calling thread, and creates a 'watch' for it. Signal delivery no longer happens asynchronously, but by wl_event_loop_dispatch() calling the dispatch callback function func.

It is the caller's responsibility to ensure that all other threads have also blocked the signal.

See also

struct wl_event_source * wl_event_loop_add_timer (struct wl_event_loop * loop, wl_event_loop_timer_func_t func, void * data)¶

Create a timer event source

Parameters

Returns

The timer is initially disarmed. It needs to be armed with a call to wl_event_source_timer_update() before it can trigger a dispatch call.

See also

void wl_event_source_check (struct wl_event_source * source)¶

Mark event source to be re-checked

Parameters

This function permanently marks the event source to be re-checked after the normal dispatch of sources in wl_event_loop_dispatch(). Re-checking will keep iterating over all such event sources until the dispatch function for them all returns zero.

Re-checking is used on sources that may become ready to dispatch as a side-effect of dispatching themselves or other event sources, including idle sources. Re-checking ensures all the incoming events have been fully drained before wl_event_loop_dispatch() returns.

int wl_event_source_fd_update (struct wl_event_source * source, uint32_t mask)¶

Update a file descriptor source's event mask

Parameters

Returns

This changes which events, readable and/or writable, cause the dispatch callback to be called on.

File descriptors are usually writable to begin with, so they do not need to be polled for writable until a write actually fails. When a write fails, the event mask can be changed to poll for readable and writable, delivering a dispatch callback when it is possible to write more. Once all data has been written, the mask can be changed to poll only for readable to avoid busy-looping on dispatch.

See also

int wl_event_source_remove (struct wl_event_source * source)¶

Remove an event source from its event loop

Parameters

Returns

The event source is removed from the event loop it was created for, and is effectively destroyed. This invalidates source . The dispatch function of the source will no longer be called through this source.

int wl_event_source_timer_update (struct wl_event_source * source, int ms_delay)¶

Arm or disarm a timer

Parameters

Returns

If the timeout is zero, the timer is disarmed.

If the timeout is non-zero, the timer is set to expire after the given timeout in milliseconds. When the timer expires, the dispatch function set with wl_event_loop_add_timer() is called once from wl_event_loop_dispatch(). If another dispatch is desired after another expiry, wl_event_source_timer_update() needs to be called again.