| SD_EVENT_SET_SIGNAL_EXIT(3) | sd_event_set_signal_exit | SD_EVENT_SET_SIGNAL_EXIT(3) |
.SH "NAME" sd_event_set_signal_exit - Automatically leave event
loop on SIGINT and SIGTERM
.SH "SYNOPSIS"
#include <systemd/sd-event.h>
.HP 696u int
sd_event_set_signal_exit(sd_event *event,
int b);
.SH "DESCRIPTION"
.PP sd_event_set_signal_exit() may be used to ensure the event loop
terminates once a SIGINT or SIGTERM signal is received. It is
a convenience wrapper around invocations of sd_event_add_signal(3)
for both signals. The two signals are automatically added to the calling
thread's signal mask (if a program is multi-threaded care should be taken to
either invoke this function before the first thread is started or to
manually block the two signals process-wide first).
.PP If the parameter b is specified as true, the event loop will
terminate on SIGINT and SIGTERM. If specified as false, it
will no longer. When this functionality is turned off the calling thread's
signal mask is restored to match the state before it was turned on, for the
two signals. By default, the two signals are not handled by the event loop,
and Linux' default signal handling for them is in effect.
.PP It is customary for UNIX programs to exit on either of these two signals,
hence it is typically a good idea to enable this functionality for the main
event loop of a program.
.SH "RETURN VALUE"
.PP sd_event_set_signal_exit() returns a positive non-zero value when
the setting was successfully changed. It returns a zero when the specified
setting was already in effect. On failure, it returns a negative errno-style
error code.
.SS "Errors"
.PP Returned errors may indicate the following problems:
.PP -ECHILD
The event loop has been created in a different process, library or module
instance.
Added in version 252.
.RE
.PP -EINVAL
The passed event loop object was invalid.
Added in version 252.
.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_set_signal_exit() was added in version 252.
.SH "SEE ALSO"
.PP systemd(1), sd-event(3), sd_event_new(3),
sd_event_add_signal(3)
| systemd 262.2 |