---
name: "sd_bus_get_connected_signal"
section: "3"
platform: "linux"
package: "libsystemd-dev"
version: "257.13-1~deb13u1"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/sd_bus_set_connected_signal"
---

# sd\_bus\_get\_connected\_signal(3)

Control emission of local connection establishment signal on bus connections

Part of [sd\_bus\_set\_connected\_signal(3)](/sd_bus_set_connected_signal/3.md).

## NAME

sd\_bus\_set\_connected\_signal, sd\_bus\_get\_connected\_signal - Control emission of local connection establishment signal on bus connections

## SYNOPSIS

```
#include <systemd/sd-bus.h>
```

**int sd\_bus\_set\_connected\_signal(sd\_bus \****bus***, int** *b***);**

**int sd\_bus\_get\_connected\_signal(sd\_bus \****bus***);**

## DESCRIPTION

**sd\_bus\_set\_connected\_signal()** may be used to control whether a local, synthetic **Connected()** signal message shall be generated and enqueued for dispatching when the connection is fully established. If the *b* parameter is zero the message is not generated (the default), otherwise it is generated.

**sd\_bus\_get\_connected\_signal()** may be used to query whether this feature is enabled. It returns zero if not, positive otherwise.

The **Connected()** signal message is generated from the "org.freedesktop.DBus.Local" service and interface, and "/org/freedesktop/DBus/Local" object path. Use [**sd\_bus\_match\_signal\_async**(3)](/sd_bus_match_signal_async/3.md) to match on this signal.

This message is particularly useful on slow transports where connections take a long time to be established. This is especially the case when [**sd\_bus\_set\_watch\_bind**(3)](/sd_bus_set_watch_bind/3.md) is used. The signal is generated when the [**sd\_bus\_is\_ready**(3)](/sd_bus_is_ready/3.md) returns positive for the first time.

The **Connected()** signal corresponds with the **Disconnected()** signal that is synthesized locally when the connection is terminated. The latter is generated unconditionally however, unlike the former which needs to be enabled explicitly before it is generated, with **sd\_bus\_set\_connected\_signal()**.

## RETURN VALUE

On success, these functions return 0 or a positive integer. On failure, they return a negative errno-style error code.

### Errors

Returned errors may indicate the following problems:

**-ECHILD**

The bus connection has been created in a different process, library or module instance.

## NOTES

Functions described here are available as a shared library, which can be compiled against and linked to with the **libsystemd** [**pkg-config**(1)](/pkg-config/1.md) file.

The code described here uses [**getenv**(3)](/getenv/3.md), which is declared to be not multi-thread-safe. This means that the code calling the functions described here must not call [**setenv**(3)](/setenv/3.md) 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\_set\_connected\_signal()** and **sd\_bus\_get\_connected\_signal()** were added in version 237.

## SEE ALSO

[**systemd**(1)](/systemd/1.md), [**sd-bus**(3)](/sd-bus/3.md), [**sd\_bus\_match\_signal\_async**(3)](/sd_bus_match_signal_async/3.md), [**sd\_bus\_set\_watch\_bind**(3)](/sd_bus_set_watch_bind/3.md), [**sd\_bus\_is\_ready**(3)](/sd_bus_is_ready/3.md)