sd_bus_set_connected_signal, sd_bus_get_connected_signal — Control emission of local connection establishment signal on bus connections
#include <systemd/sd-bus.h>
int sd_bus_set_connected_signal( | sd_bus *bus, |
int b); |
int sd_bus_get_connected_signal( | sd_bus *bus); |
sd_bus_set_connected_signal() may be used to control whether a local, synthetic
Connected() signal message shall be generated and enqueued for dispatching when the connection
is fully established. If the b parameter is zero the message is not generated (the default),
otherwise it is generated.
sd_bus_get_connected_signal() may be used to query whether this feature is enabled. It
returns zero if not, positive otherwise.
The Connected() signal message is generated from the
"org.freedesktop.DBus.Local" service and interface, and
"/org/freedesktop/DBus/Local" object path. Use
sd_bus_match_signal_async(3) to
match on this signal.
This message is particularly useful on slow transports where connections take a long time to be established. This is especially the case when sd_bus_set_watch_bind(3) is used. The signal is generated when the sd_bus_is_ready(3) returns positive for the first time.
The Connected() signal corresponds with the Disconnected() signal
that is synthesized locally when the connection is terminated. The latter is generated unconditionally however,
unlike the former which needs to be enabled explicitly before it is generated, with
sd_bus_set_connected_signal().
On success, these functions return 0 or a positive integer. On failure, they return a negative errno-style error code.
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.