SD_BUS_START
Section: sd_bus_start (3)
Updated:
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NAME
sd_bus_start - Initiate a bus connection to the D-bus broker daemon
SYNOPSIS
#include <systemd/sd-bus.h>
-
int sd_bus_start(sd_bus *bus);
DESCRIPTION
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.
RETURN VALUE
On success, this function returns a non-negative integer. On failure, it returns a negative errno-style error code.
Errors
-EINVAL
-
The input parameter
bus
is
NULL.
-ENOPKG
-
Bus object
bus
could not be resolved.
-EPERM
-
The input parameter
bus
is in a wrong state (sd_bus_start()
may only be called once on a newly-created bus object).
-ECHILD
-
The bus object
bus
was created in a different process.
In addition, other connection-related errors may be returned. See
sd_bus_send(3).
NOTES
These APIs are implemented as a shared library, which can be compiled and linked to with the
libsystemd pkg-config(1)
file.
SEE ALSO
systemd(1),
sd-bus(3),
sd_bus_default(3),
sd_bus_call_async(3)