Man page - sd_bus_start(3)

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Manual

SD_BUS_START

NAME
SYNOPSIS
DESCRIPTION
RETURN VALUE
Errors
NOTES
HISTORY
SEE ALSO

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 .

Added in version 246.

-ENOPKG

Bus object bus could not be resolved.

Added in version 246.

-EPERM

The input parameter bus is in a wrong state ( sd_bus_start() may only be called once on a newly-created bus object).

Added in version 246.

-ECHILD

The bus object bus was created in a different process.

Added in version 246.

In addition, other connection-related errors may be returned. See sd_bus_send (3).

NOTES

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.

HISTORY

sd_bus_start() was added in version 246.

SEE ALSO

systemd (1), sd-bus (3), sd_bus_default (3), sd_bus_call_async (3)