Manpages - sd_bus_start.3
Table of Contents
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)