определите функцию обратного вызова для очистки ресурсов (define the callback function for resource cleanup)
Имя (Name)
sd_event_source_set_destroy_callback,
sd_event_source_get_destroy_callback, sd_event_destroy_t - Define
the callback function for resource cleanup
Синопсис (Synopsis)
#include <systemd/sd-event.h>
typedef int (*sd_event_destroy_t)(void *userdata);
int sd_event_source_set_destroy_callback(sd_event_source *source,
sd_event_destroy_t callback);
int sd_event_source_get_destroy_callback(sd_event_source *source,
sd_event_destroy_t *callback);
Описание (Description)
sd_event_source_set_destroy_callback() sets callback as the
callback function to be called right before the event source
object source is deallocated. The userdata pointer from the event
source object will be passed as the userdata parameter. This
pointer can be set by an argument to the constructor functions,
see sd_event_add_io(3), or directly, see
sd_event_source_set_userdata(3). This callback function is called
even if userdata is NULL. Note that this callback is invoked at a
time where the event source object itself is already invalidated,
and executing operations or taking new references to the event
source object is not permissible.
sd_event_source_get_destroy_callback() returns the current
callback for source in the callback parameter.
Возвращаемое значение (Return value)
On success, sd_event_source_set_destroy_callback() returns 0 or a
positive integer. On failure, it returns a negative errno-style
error code.
sd_event_source_get_destroy_callback() returns positive if the
destroy callback function is set, 0 if not. On failure, returns a
negative errno-style error code.
Errors
Returned errors may indicate the following problems:
-EINVAL
The source parameter is NULL.
Примечание (Note)
These APIs are implemented as a shared library, which can be
compiled and linked to with the libsystemd pkg-config(1) file.
Смотри также (See also)
systemd(1), sd-event(3), sd_event_add_io(3),
sd_event_add_time(3), sd_event_add_signal(3),
sd_event_add_child(3), sd_event_add_inotify(3),
sd_event_add_defer(3), sd_event_source_set_userdata(3)
