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sd_get_seats(3) — Linux manual page

SD_GET_SEATS(3)                sd_get_seatsSD_GET_SEATS(3)

NAME        top

       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        top

#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        top

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, aNULL-terminated array of seat       identifiers is stored at the address. The returned array and all       strings it references need to be freed with the libcfree(3) call       after use. Note that instead of an empty arrayNULLmay 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        top

       On success,sd_get_seats(),sd_get_sessions(),sd_get_uids()andsd_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        top

       Functions described here are available as a shared library, which       can be compiled against and linked to with thelibsystemd pkg-config(1) file.       The code described here usesgetenv(3), which is declared to be       not multi-thread-safe. This means that the code calling the       functions described here must not callsetenv(3) from a parallel       thread. It is recommended to only do calls tosetenv()from an       early phase of the program when no other threads have been       started.

HISTORY        top

sd_get_machine_names()was added in version 203.

SEE ALSO        top

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

COLOPHON        top

       This page is part of thesystemd (systemd system and service       manager) project.  Information about the project can be found at       ⟨http://www.freedesktop.org/wiki/Software/systemd⟩.  If you have a       bug report for this manual page, see       ⟨http://www.freedesktop.org/wiki/Software/systemd/#bugreports⟩.       This page was obtained from the project's upstream Git repository       ⟨https://github.com/systemd/systemd.git⟩ on 2025-08-11.  (At that       time, the date of the most recent commit that was found in the       repository was 2025-08-11.)  If you discover any rendering       problems in this HTML version of the page, or you believe there is       a better or more up-to-date source for the page, or you have       corrections or improvements to the information in this COLOPHON       (which isnot part of the original manual page), send a mail to       man-pages@man7.orgsystemd 258~rc2SD_GET_SEATS(3)

Pages that refer to this page:procps_misc(3), sd-login(3), sd_login_monitor_new(3), systemd.directives(7), systemd.index(7)

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