| SD_EVENT_EXIT(3) | sd_event_exit | SD_EVENT_EXIT(3) |
.SH "NAME" sd_event_exit, sd_event_get_exit_code - Ask the event
loop to exit
.SH "SYNOPSIS"
#include <systemd/sd-event.h>
.HP 432u int sd_event_exit(sd_event *event,
int code);
.HP 648u int sd_event_get_exit_code(sd_event *event,
int *ret);
.SH "DESCRIPTION"
.PP sd_event_exit() requests the event loop specified in the
event event loop object to exit. The code parameter may be any
integer value and is returned as-is by sd_event_loop(3) after the
last event loop iteration. It may also be queried using
sd_event_get_exit_code(), see below.
.PP When exiting is requested the event loop will stop listening for and
dispatching regular event sources. Instead it will proceed with executing
only event sources registered with sd_event_add_exit(3) in the order
defined by their priority. After all exit event sources have been dispatched
the event loop is terminated.
.PP If sd_event_exit() is invoked a second time while the event loop
is still processing exit event sources, the exit code stored in the event
loop object is updated, but otherwise no further operation is executed.
.PP sd_event_get_exit_code() may be used to query the exit code passed
to an earlier call of sd_event_exit(). The return parameter
ret may be set to NULL, in order to simply check if
sd_event_exit() has been called before (as
sd_event_get_exit_code() fails with -ENODATA if that's not the
case, see below).
.PP While the full positive and negative integer ranges may be used for the
exit code, care should be taken not pick exit codes that conflict with
regular exit codes returned by sd_event_loop(), if these exit codes
shall be distinguishable.
.PP Note that for most event source types passing the callback pointer as
NULL in the respective constructor call (i.e. in
sd_event_add_time(3), sd_event_add_signal(3), ...) has the
effect of sd_event_exit() being invoked once the event source
triggers, with the specified userdata pointer cast to an integer as the exit
code parameter. This is useful to automatically terminate an event loop
after some condition, such as a timeout or reception of SIGTERM or
similar. See the documentation for the respective constructor call for
details.
.SH "RETURN VALUE"
.PP On success, sd_event_exit() and sd_event_get_exit_code()
return 0 or a positive integer. On failure, they return a negative
errno-style error code.
.SS "Errors"
.PP Returned errors may indicate the following problems:
.PP -EINVAL
The event loop object or error code pointer are invalid.
.RE
.PP -ECHILD
The event loop was created in a different process, library or module
instance.
.RE
.PP -ESTALE
The event loop has exited already and all exit handlers are already
processed.
.RE
.PP -ENODATA
Returned by sd_event_get_exit_code() in case the event loop has not
been requested to exit yet.
.RE
.SH "NOTES"
.PP Functions described here are available as a shared library, which can be
compiled against and linked to with the
libsystemd pkg-config(1) file.
.PP All functions listed here are thread-agnostic and only a single thread
may operate on a given object at any given time. Different threads may
access the same object at different times. Multiple independent objects may
be used from different threads in parallel.
.PP 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.
.SH "HISTORY"
.PP sd_event_exit() and sd_event_get_exit_code() were added in
version 229.
.SH "SEE ALSO"
.PP systemd(1), sd-event(3), sd_event_new(3),
sd_event_add_exit(3), sd_event_add_time(3),
sd_event_add_signal(3), sd_event_add_io(3),
sd_event_add_defer(3), sd_event_add_inotify(3)
| systemd 262.2 |