sd_get_seats

Index · Directives systemd 234

## Name

sd_get_seats, sd_get_sessions, sd_get_uids, sd_get_machine_names — Determine available seats, sessions, logged in users and virtual machines/containers

## Synopsis

    #include <systemd/sd-login.h>

`int sd_get_seats(` | char ***seats`)`;

`int sd_get_sessions(` | char ***sessions`)`;

`int sd_get_uids(` | uid_t **users`)`;

`int sd_get_machine_names(` | char ***machines`)`;

## Description

`sd_get_seats()` may be used to determine all currently available local seats. Returns the number of seat identifiers and if the input pointer is non-NULL, a `NULL`-terminated array of seat identifiers is stored at the address. The returned array and all strings it references need to be freed with the libc free(3) call after use. Note that instead of an empty array `NULL` may be returned and should be considered equivalent to an empty array.

Similarly, `sd_get_sessions()` may be used to determine all current login sessions.

Similarly, `sd_get_uids()` may be used to determine all Unix users who currently have login sessions.

Similarly, `sd_get_machine_names()` may be used to determine all current virtual machines and containers on the system.

Note that the returned lists are not sorted and in an undefined order.

## Return Value

On success, `sd_get_seats()`, `sd_get_sessions()`, `sd_get_uids()` and `sd_get_machine_names()` return the number of entries in the arrays. On failure, these calls return a negative errno-style error code.

## Errors

Returned errors may indicate the following problems:

`-ENOMEM`

  Memory allocation failed.

## Notes

The `sd_get_seats()`, `sd_get_sessions()`, `sd_get_uids()` and `sd_get_machine_names()` interfaces are available as a shared library, which can be compiled and linked to with the `libsystemd` pkg-config(1) file.

## See Also

systemd(1), sd-login(3), sd_session_get_seat(3)