x SuSE Linux 13.1-RELEASE x
x SuSE Linux 13.1-RELEASEx
SD_EVENT_RUN(3) sd_event_run SD_EVENT_RUN(3)
NAME
sd_event_run, sd_event_loop - Run an event loop
SYNOPSIS
#include <systemd/sd-event.h>
int sd_event_run(sd_event *event, uint64_t usec);
int sd_event_loop(sd_event *event);
DESCRIPTION
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_exit(3).
The event loop object event is created with sd_event_new(3). Events
sources to wait for and their handlers may be registered with
sd_event_add_io(3), sd_event_add_time(3), sd_event_add_signal(3),
sd_event_add_child(3), sd_event_add_defer(3), sd_event_add_post(3) and
sd_event_add_exit(3).
For low-level control of event loop execution, use sd_event_prepare(3),
sd_event_wait(3) and sd_event_dispatch(3) which are wrapped by
sd_event_run(). Along with sd_event_get_fd(3), these functions allow
integration of an sd-event(3) event loop into foreign event loop
implementations.
RETURN VALUE
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().
Errors
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_prepare(3) 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.
NOTES
Functions described here are available as a shared library, which can
be compiled against and linked to with the libsystemd pkg-config(1)
file.
The code described here uses getenv(3), which is declared to be not
multi-thread-safe. This means that the code calling the functions
described here must not call setenv(3) from a parallel thread. It is
recommended to only do calls to setenv() from an early phase of the
program when no other threads have been started.
SEE ALSO
systemd(1), sd-event(3), sd_event_new(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_exit(3),
sd_event_get_fd(3), sd_event_wait(3), GLib Main Event Loop[1]
NOTES
1. GLib Main Event Loop
https://developer.gnome.org/glib/unstable/glib-The-Main-Event-Loop.html
systemd 254 SD_EVENT_RUN(3)
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