systemd sd_event_run 3 sd_event_run sd_event_loop Run an event loop #include <systemd/sd-event.h> int sd_event_run sd_event *event uint64_t usec int sd_event_loop sd_event *event sd_event_run() may be used to run a single iteration of the event loop specified in the event parameter. The function waits until an event to process is available, and dispatches the registered handler for it. The usec parameter specifies the maximum time (in microseconds) to wait for an event. Use (uint64_t) -1 to specify an infinite timeout. sd_event_loop() invokes sd_event_run() in a loop, thus implementing the actual event loop. The call returns as soon as exiting was requested using sd_event_exit3. The event loop object event is created with sd_event_new3. Events sources to wait for and their handlers may be registered with sd_event_add_io3, sd_event_add_time3, sd_event_add_signal3, sd_event_add_child3, sd_event_add_defer3, sd_event_add_post3 and sd_event_add_exit3. For low-level control of event loop execution, use sd_event_prepare3, sd_event_wait3 and sd_event_dispatch3 which are wrapped by sd_event_run(). Along with sd_event_get_fd3, these functions allow integration of an sd-event3 event loop into foreign event loop implementations. On failure, these functions return a negative errno-style error code. sd_event_run() returns a positive, non-zero integer if an event source was dispatched, and zero when the specified timeout hit before an event source has seen any event, and hence no event source was dispatched. sd_event_loop() returns the exit code specified when invoking sd_event_exit(). Returned errors may indicate the following problems: -EINVAL The event parameter is invalid or NULL. -EBUSY The event loop object is not in the right state (see sd_event_prepare3 for an explanation of possible states). -ESTALE The event loop is already terminated. -ECHILD The event loop has been created in a different process, library or module instance. Other errors are possible, too. sd_event_run() and sd_event_loop() were added in version 220. systemd1, sd-event3, sd_event_new3, sd_event_add_io3, sd_event_add_time3, sd_event_add_signal3, sd_event_add_child3, sd_event_add_inotify3, sd_event_add_defer3, sd_event_exit3, sd_event_get_fd3, sd_event_wait3, GLib Main Event Loop