sd_bus_start — Initiate a bus connection to the D-bus broker daemon
#include <systemd/sd-bus.h>
int sd_bus_start( | sd_bus *bus); |
sd_bus_start() connects an existing bus connection object to the D-Bus
broker daemon, usually
dbus-daemon(1)
or
dbus-broker(1).
The mechanism to use for the connection must be configured before the call to
sd_bus_start(), using one of
sd_bus_set_address(3),
sd_bus_set_fd(3), or
sd_bus_set_exec(3).
sd_bus_start() will open the connection socket or spawn the executable as
needed, and asynchronously start a org.freedesktop.DBus.Hello() call. The
answer to the Hello call will be processed later from
sd_bus_process(3). If
opening of the connection or queuing of the asynchronous call fail, the connection will be closed with
sd_bus_close(3).
In most cases, it is better to use
sd_bus_default_user(3),
sd_bus_default_system(3)
or related calls instead of the more low-level sd_bus_new() and
sd_bus_start(). The higher-level functions not only allocate a bus object but also
start the connection to a well-known bus in a single function call.
On success, this function returns a non-negative integer. On failure, it returns a negative errno-style error code.
In addition, other connection-related errors may be returned. See sd_bus_send(3).
Functions described here are available as a shared
library, which can be compiled against and linked to with the
libsystemd pkg-config(1)
file.
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.
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.