sd_bus_start − Initiate a bus connection to the D−bus broker daemon
#include <elogind/sd−bus.h>
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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.
−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).
These APIs are implemented as a shared library, which can be compiled and linked to with the libelogind pkg-config(1) file.
elogind(8), sd-bus(3), sd_bus_default(3), sd_bus_call_async(3)