---
name: "libsystemd"
section: "3"
platform: "linux"
package: "systemd-libs"
version: "262.1-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/libsystemd"
---

# libsystemd(3)

Functions for implementing services and interacting with systemd

## NAME

libsystemd - Functions for implementing services and interacting with systemd

## SYNOPSIS

```
#include <systemd/sd-bus.h>
#include <systemd/sd-daemon.h>
#include <systemd/sd-device.h>
#include <systemd/sd-event.h>
#include <systemd/sd-gpt.h>
#include <systemd/sd-hwdb.h>
#include <systemd/sd-id128.h>
#include <systemd/sd-journal.h>
#include <systemd/sd-json.h>
#include <systemd/sd-login.h>
#include <systemd/sd-messages.h>
#include <systemd/sd-path.h>
#include <systemd/sd-varlink.h>
```

**pkg-config --cflags --libs libsystemd**

## DESCRIPTION

The libsystemd library provides functions that allow interacting with various interfaces provided by the [**systemd**(1)](/systemd/1.md) service manager, as well as various other functions and constants useful for implementing services in general.

See [**sd-bus**(3)](/sd-bus/3.md), [**sd-bus-errors**(3)](/sd-bus-errors/3.md), [**sd-daemon**(3)](/sd-daemon/3.md), [**sd-device**(3)](/sd-device/3.md), [**sd-event**(3)](/sd-event/3.md), [**sd-hwdb**(3)](/sd-hwdb/3.md), [**sd-id128**(3)](/sd-id128/3.md), [**sd-journal**(3)](/sd-journal/3.md), [**sd-json**(3)](/sd-json/3.md), [**sd-login**(3)](/sd-login/3.md), [**sd-path**(3)](/sd-path/3.md), and [**sd-varlink**(3)](/sd-varlink/3.md) for information about different parts of the library interface.

## INTERFACE STABILITY

Strict backwards-compatibility is maintained for the API (application programming interface) and ABI (application binary interface). Symbol versioning is used, with symbols only added and never removed.

## 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.

## SEE ALSO

[**systemd**(1)](/systemd/1.md), [**libudev**(3)](/libudev/3.md), [**pkg-config**(1)](/pkg-config/1.md), **Interface Portability and Stability Promise**\[1\]

## NOTES

- 1\.

  Interface Portability and Stability Promise

  https://systemd.io/PORTABILITY\_AND\_STABILITY/