systemd Developer Tom Gundersen teg@jklm.no sd_event_run 3 sd_event_run sd_event_loop Run the libsystemd event loop #include <systemd/sd-event.h> int sd_event_run sd_event *event uint64_t timeout int sd_event_loop sd_event *event sd_event_run() can be used to run one iteration of the event loop of libsystemd. This function waits until an event to process is available, and dispatches a handler for it. The timeout parameter specifices the maximum time (in microseconds) to wait. (uint64_t) -1 may be used to specify an infinite timeout. sd_event_loop runs sd_event_wait in a loop with a timeout of infinity. This makes it suitable for the main event loop of a program. The event loop object event is created with sd_event_new. Events to wait for and their handlers can be registered with sd_event_add_time, sd_event_add_child, sd_event_add_signal, sd_event_add_defer, sd_event_add_exit, and sd_event_add_post. For more fine-grained control, sd_event_prepare, sd_event_wait, and sd_event_dispatch may be used. Along with sd_event_get_fd, those functions make it possible to integrate the libsystemd loop inside of another event loop. On success, these functions return 0 or a positive integer. On failure, they return a negative errno-style error code. sd_event_run returns 0 if the event loop is finished, and a positive value if it can be continued. Returned errors may indicate the following problems: -EINVAL The event parameter is 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. Other errors are possible, too. sd_event_run() and sd_event_loop() are available as a shared library, which can be compiled and linked to with the libsystemd pkg-config1 file. systemd1, sd_event_new3, sd_event_wait3, sd_event_add_io3, sd_event_add_time3, sd_event_add_signal3, sd_event_add_defer3, sd_event_add_exit3, sd_event_add_post3, GLib Main Event Loop.